WO2009125896A1

WO2009125896A1 - Wafer testing apparatus and processing equipment having the same

Info

Publication number: WO2009125896A1
Application number: PCT/KR2008/002795
Authority: WO
Inventors: Soon-Jong Lee; Bong-Joo Woo
Original assignee: Semisysco Co Ltd
Current assignee: Semisysco Co Ltd
Priority date: 2008-04-08
Filing date: 2008-05-19
Publication date: 2009-10-15
Anticipated expiration: 2010-10-08
Also published as: CN101990706A; KR101060712B1; TW200943447A; TWI388021B; KR20090107400A

Abstract

The present invention provides a wafer testing apparatus. The wafer testing apparatus includes a wafer transferring part which transfers a wafer along a transfer path, and is placed near an edge of the wafer to be transferred, inspects whether a crack or a particle exists in the edge of the wafer, and distinguishes between the crack and the particle. There is provided an inspector for taking out the wafer to another transfer path if there exists the crack or the particle. Further, the present invention provides processing equipment having the wafer testing apparatus, which can inspect qualities of a wafer to be introduced into a series of processes and determine whether to introduce or take out the wafer into or from a processing chamber or the next series of processes according to results from inspecting the qualities.

Description

WAFER TESTING APPARATUS AND PROCESSING EQUIPMENT HAVING THE SAME

Technical Field

[1] The present invention relates to processing equipment, and more particularly to a wafer testing apparatus, which can inspect qualities of a wafer to be introduced into a series of processes and determine whether to introduce or take out the wafer into or from a processing chamber or the next series of processes according to results from inspecting the qualities, and processing equipment having the same. Background Art

[2] In general, a thin film transistor liquid crystal display includes a lower glass substrate on which a thin film transistor is formed, an upper glass substrate on which a color filter is formed, and liquid crystal interposed between the lower glass substrate and the upper glass substrate.

[3] Such a glass substrate for forming the thin film transistor and the color filter thereon is damaged at an edge thereof while undergoing a series of process, and accordingly if the glass substrate having the damaged edge or the like is being carried to the next process or is introduced into a processing chamber, there is a problem that it may be broken in the chamber or in a certain space on the way to the next process.

[4] Conventionally, there is a problem that restoration thereof is very time-consuming.

[5] Further, a vision inspection is conventionally performed for inspecting a state of the substrate.

[6] In the case that the damaged edge or the like, e.g., a crack of the glass substrate, is observed through only the vision inspection, there is a problem that foreign materials such as particles on the substrate, which can be cleaned in the next cleaning process, are excessively detected.

[7] Also, in the case where broken glass or the particles from the outside or the inside are attached to a top surface of the glass substrate, the broken glass or the like may damage equipment used in the following processes.

[8] For the above-described reasons, there are problems that a running time of the equipment is prolonged and costs of maintaining and repairing the equipment increase.

[9] Accordingly, general qualities of the glass substrate are conventionally inspected before applying processes using plasma, such as deposition, etching, sputtering, etc. to the glass substrate in the processing chamber.

[10] However, the conventional inspection to the surface of the glass substrate uses the vision inspection. Therefore, the crack and the particle are not strictly distinguished from each other. Further, there is a problem that many vision cameras are needed for inspecting metal or broken glass on the surface of the glass substrate.

[11] Since the crack and the particle on the substrate are not distinguished from each other, even particles that can be sufficiently cleaned are conventionally detected. Thus, the detection is not correctly performed.

[12] Accordingly, development of various technologies has recently been required so that it is possible to determine whether there exist cracks or particles on the top surface and the edge of the glass substrate and to distinguish them from each other before introducing the glass substrate into the processing chamber where a series of processes is performed or into the next process. Disclosure of Invention Technical Problem

[13] The present invention is conceived to solve the problems as described above, and an object of the present invention is to provide a wafer testing apparatus, which can inspect qualities (existence of a crack or a particle) of a wafer to be introduced into a series of processes and determine whether to introduce or take out the wafer into or from a processing chamber or the next series of processes according to results from inspecting the qualities, and processing equipment having the same.

[14] Another object of the present invention is to provide a wafer testing apparatus, which can easily inspect an edge of a substrate as an improved integrating body is placed near the edge of the substrate and a laser is emitted to an edge part of the substrate so as to detect light quantity of the laser passed through the substrate by the integrating body, and processing equipment having the same.

[15] Still another object of the present invention is to provide a wafer testing apparatus, which can inspect quality of an inside or a top surface of a wafer by emitting a line beam along a lengthwise direction or the top surface of the substrate, and processing equipment having the same. Technical Solution

[16] According to an aspect of the present invention, a wafer testing apparatus may include: a wafer transferring part which transfers a wafer along a transfer path; and an inspector which is placed near an edge of the wafer to be transferred, inspects whether a crack or a particle exists in the edge of the wafer, and distinguishes between the crack and the particle.

[17] The inspector may include a first inspector and a second inspector, the first inspector including a first laser generator placed below the edge of the wafer and emitting a laser, a first inspecting module placed above the edge of the wafer and determining whether the crack or the particle exists in the edge of the wafer and distinguishing between the crack and the particle by detecting quantity of the laser passing through the edge of the substrate, incident to and exiting from an opposite side, and a photographing module photographing an outer surface of the wafer, and the second inspector including a second laser generator placed at a lateral side of the wafer to be transferred and emitting a laser along a lengthwise direction of the wafer, a vertically- movable cylinder connected to the second laser generator and vertically moving an illumination position of the laser to a certain position, and a second inspecting module placed above the wafer and detecting the laser scattered from the wafer.

[18] The inspector may include a transferring unit, the transferring unit being electrically connected to the first and second inspecting modules and taking out the wafer toward another transfer path when the crack exists in the wafer or when the second inspecting module detects the laser.

[19] The first inspecting module may be an integrating body that includes a body including a light incident part, a light exit part opposite to the light incident part, and a diffused- light exit part placed between the light incident part and the light exit part and allowing the light incident to the light incident part to be diffused and exit, and forming a predetermined inner space, a first optical detector provided in the diffused- light exit part and detecting the quantity of the diffused-light, a second optical detector provided in the light exit part and detecting the quantity of the light incident to the light incident part and exiting through the light exit part, and a monitoring module electrically connected to the first and second optical detectors and determining whether the crack or the particle exists and distinguishing between the crack and the particle on the basis of the detected light quantity, and the photographing module may include a light source placed in one side of the wafer and illuminating the wafer, and a camera placed in the other side of the wafer and photographing the outer surface of the wafer.

[20] The first inspecting module may be an optical system that includes a lens placed in the vicinity of the wafer and condensing the laser, and a photodiode placed in the vicinity of the lens and detecting the quantity of the laser.

[21] The body may have a cylindrical shape.

[22] The second inspecting module may be placed above the wafer and include a plurality of photodiodes.

[23] The second inspecting module may be an integrating body that includes a body including a light incident part, a light exit part opposite to the light incident part, and a diffused-light exit part placed between the light incident part and the light exit part and allowing the light incident to the light incident part to be diffused and exit, and forming a predetermined inner space, a first optical detector provided in the diffused-light exit part and detecting the quantity of the diffused-light, a second optical detector provided in the light exit part and detecting the quantity of the light incident to the light incident part and exiting through the light exit part, and a monitoring module electrically connected to the first and second optical detectors and determining whether the crack or the particle exists and distinguishing between the crack and the particle on the basis of the detected light quantity.

[24] The inner space may include a first space having a predetermined length and formed in parallel, and second spaces placed at opposite sides of the first space, having a hemispherical shape and communicating with the first space, and the first and second spaces may communicate with the light incident part and the light exit part.

[25] The light incident part and the light exit part may each include a hole having the same length and linearly formed along the lengthwise direction of the body, and the diffused- light exit part may include a plurality of through holes nonlinearly formed along the lengthwise direction of the body.

[26] The body may include a detachable body to be fitted to the inner space, the detachable body including a third space having a predetermined length and formed in parallel; fourth spaces provided at opposite sides of the third space, having a hemispherical shape and communicating with the third space; and an auxiliary light incident part and an auxiliary light exit part through which the third and fourth spaces communicate with the light incident part and the light exit part.

[27] The first optical detector and the second optical detector may include photodiodes.

[28] The monitoring module may include: a controller installed in the body, electrically connected to the first and second optical detectors, determining whether the detected quantity of the light is within a reference light quantity range, determining whether the detected quantity of the diffused-light is within a reference diffused- light quantity range, determining whether the crack or the particle exists, and distinguishing between the crack and the particle; and a display installed in the body, electrically connected to the controller, visually displaying the reference light quantity range preset for the detected quantity of the light, visually displaying whether the detected quantity of the light is within the reference light quantity range, visually displaying the reference diffused-light quantity range preset for the detected quantity of the diffused-light, and visually displaying whether the detected quantity of the diffused-light is within the reference diffused-light quantity range, wherein the reference light quantity range includes a first reference light quantity range for distinguishing the crack, and a second reference light quantity range for distinguishing the particle, and wherein the reference diffused-light quantity range includes a first reference diffused-light quantity range for distinguishing the crack, and a second reference diffused-light quantity range for distinguishing the particle.

[29] According to another aspect of the present invention, processing equipment having a wafer testing apparatus may include: a chamber internally formed with a transfer path for a wafer; a wafer transferring part placed close to the chamber and transferring the wafer to the chamber along the transfer path; and a wafer testing apparatus including an inspector which is placed near an edge of the wafer to be transferred, inspects whether a crack or a particle exists in the edge of the wafer, distinguishes between the crack and the particle, and takes out the wafer along another transfer path.

[30] The inspector may include a first inspector and a second inspector, the first inspector including a first laser generator placed below the edge of the wafer and emitting a laser, a first inspecting module placed above the edge of the wafer and determining whether the crack or the particle exists in the edge of the wafer and distinguishing between the crack and the particle by detecting quantity of the laser passing through the edge of the substrate, incident to and exiting from an opposite side, and a photographing module photographing an outer surface of the wafer, and the second inspector including a second laser generator placed at a lateral side of the wafer to be transferred and emitting a laser along a lengthwise direction of the wafer, a vertically- movable cylinder connected to the second laser generator and vertically moving an illumination position of the laser to a certain position, and a second inspecting module placed above the wafer and detecting the laser scattered from the wafer.

[31] The inspector may include a transferring unit, the transferring unit being electrically connected to the first and second inspecting modules and taking out the wafer toward another transfer path when the crack exists in the wafer or when the second inspecting module detects the laser.

[32] The first inspecting module may be an integrating body that includes a body including a light incident part, a light exit part opposite to the light incident part, and a diffused- light exit part placed between the light incident part and the light exit part and allowing the light incident to the light incident part to be diffused and exit, and forming a predetermined inner space, a first optical detector provided in the diffused- light exit part and detecting the quantity of the diffused-light, a second optical detector provided in the light exit part and detecting the quantity of the light incident to the light incident part and exiting through the light exit part, and a monitoring module electrically connected to the first and second optical detectors and determining whether the crack or the particle exists and distinguishing between the crack and the particle on the basis of the detected light quantity, and the photographing module may include a light source placed in one side of the wafer and illuminating the wafer, and a camera placed in the other side of the wafer and photographing the outer surface of the wafer.

[33] The first inspecting module may be an optical system that includes a lens placed in the vicinity of the wafer and condensing the laser, and a photodiode placed in the vicinity of the lens and detecting the quantity of the laser.

[34] The body may have a cylindrical shape. [35] The second inspecting module may be placed above the wafer and include a plurality of photodiodes.

[36] The second inspecting module may be an integrating body that includes a body including a light incident part, a light exit part opposite to the light incident part, and a diffused- light exit part placed between the light incident part and the light exit part and allowing the light incident to the light incident part to be diffused and exit, and forming a predetermined inner space, a first optical detector provided in the diffused- light exit part and detecting the quantity of the diffused-light, a second optical detector provided in the light exit part and detecting the quantity of the light incident to the light incident part and exiting through the light exit part, and a monitoring module electrically connected to the first and second optical detectors and determining whether the crack or the particle exists and distinguishing between the crack and the particle on the basis of the detected light quantity.

[37] The inner space may include a first space having a predetermined length and formed in parallel, and second spaces placed at opposite sides of the first space, having a hemispherical shape and communicating with the first space, and the first and second spaces may communicate with the light incident part and the light exit part.

[38] The light incident part and the light exit part may each include a hole having the same length and linearly formed along the lengthwise direction of the body, and the diffused-light exit part may include a plurality of through holes nonlinearly formed along the lengthwise direction of the body.

[39] The body may include a detachable body to be fitted to the inner space, the detachable body including a third space having a predetermined length and formed in parallel; fourth spaces provided at opposite sides of the third space, having a hemispherical shape and communicating with the third space; and an auxiliary light incident part and an auxiliary light exit part through which the third and fourth spaces communicate with the light incident part and the light exit part.

[40] The first optical detector and the second optical detector may include photodiodes.

[41] The monitoring module may include: a controller installed in the body, electrically connected to the first and second optical detectors, determining whether the detected quantity of the light is within a reference light quantity range, determining whether the detected quantity of the diffused-light is within a reference diffused-light quantity range, determining whether the crack or the particle exists, and distinguishing between the crack and the particle; and a display installed in the body, electrically connected to the controller, visually displaying the reference light quantity range preset for the detected quantity of the light, visually displaying whether the detected quantity of the light is within the reference light quantity range, visually displaying the reference diffused-light quantity range preset for the detected quantity of the diffused-light, and visually displaying whether the detected quantity of the diffused-light is within the reference diffused-light quantity range, wherein the reference light quantity range includes a first reference light quantity range for distinguishing the crack, and a second reference light quantity range for distinguishing the particle, and wherein the reference diffused-light quantity range includes a first reference diffused-light quantity range for distinguishing the crack, and a second reference diffused-light quantity range for distinguishing the particle.

Advantageous Effects

[42] The present invention is effective in inspecting qualities (existence of a crack or a particle) of a wafer to be introduced into a series of processes and determining whether to introduce or take out the wafer into or from a processing chamber or the next series of processes according to results from inspecting the qualities [43] Also, the present invention is effective in easily inspecting an edge of a substrate as an improved integrating body is placed near the edge of the substrate and a laser is emitted to an edge part of the substrate so as to detect light quantity of the laser passed through the substrate by the integrating body. [44] Further, the present invention is effective in inspecting quality of an inside or a top surface of a wafer by emitting a line beam along a lengthwise direction or the top surface of the substrate.

Brief Description of the Drawings [45] FIG. 1 illustrates processing equipment having a wafer testing apparatus according to an embodiment of the present invention. [46] FIG. 2 illustrates processing equipment having a wafer testing apparatus according to another embodiment of the present invention. [47] FIG. 3 illustrates processing equipment having a wafer testing apparatus according to a third embodiment of the present invention. [48] FIG. 4 is a plan view illustrating a layout of an inspector and a conveyer-type wafer carrier in the wafer testing apparatus according to an embodiment of the present invention. [49] FIG. 5 illustrates a wafer testing apparatus according to an embodiment of the present invention.

[50] FIG. 6 shows a different layout of an integrating body in FIG. 5.

[51] FIG. 7 illustrates a wafer testing apparatus according to another embodiment of the present invention.

[52] FIG. 8 shows a different layout of an optical system in FIG. 7.

[53] FIG. 9 shows a second inspector in FIG. 5.

[54] FIG. 10 illustrates an operation of the second inspector of FIG. 9. [55] FIG. 11 is a bottom view of a photodiode structure according to an embodiment of the present invention.

[56] FIG. 12 illustrates another operation of the second inspector of FIG. 9.

[57] FIG. 13 is a perspective view of an integrating body according to an embodiment of the present invention.

[58] FIG. 14 is a cross-sectional view taken along line I-I of FIG. 13.

[59] FIG. 15 is a cross-sectional view showing another example of an inner space of the integrating body of FIG. 13.

[60] FIG. 16 is a block diagram of a monitoring module of FIG. 13.

[61] FIG. 17 is a perspective view of an integrating body according to another embodiment of the present invention.

[62] FIG. 18 is a cross-sectional view of the integrating body of FIG. 17.

[63] FIG. 19 is a block diagram of a monitoring module of FIG. 17.

[64] FIG. 20 is a cross-sectional view showing another example of an integrating body according to a third embodiment of the present invention.

[65] ** Reference Numerals of Main Elements**

[66] PC: processing chamber

[67] A: wafer testing apparatus

[68] 500: wafer transferring part

[69] 600: inspector

[70] 610: first inspector

[71] 611: first laser generator

[72] 100: integrating body

[73] 620: second inspector

[74] 622: vertically-movable cylinder

[75] 623: photodiode structure

Best Mode for Carrying Out the Invention

[76] Below, a wafer testing apparatus and processing equipment according to embodiments of the present invention will be described with reference to accompanying drawings.

[77] FIG. 1 illustrates processing equipment having a wafer testing apparatus according to an embodiment of the present invention.

[78] A wafer testing apparatus A according to an embodiment of the present invention includes a wafer transferring unit 500 to transfer a wafer 10 along a transfer path a; and an inspector 600 that is placed near an edge of the wafer 10, inspects where a crack and a particle exist in the edge of the wafer 10, and takes out the wafer 10 toward another transfer path c when the crack or the particle exists. [79] As shown in FIG. 1, the wafer testing apparatus A with this configuration is provided in the vicinity of a processing chamber PC where a series of processes is performed. The wafer 10 may be introduced into the processing chamber PC along the transfer path a.

[80] FIG. 2 illustrates processing equipment having a wafer testing apparatus according to another embodiment of the present invention.

[81] As shown in FIG. 2, the wafer testing apparatus A with the foregoing configuration is placed in the vicinity of a carrier 20 loaded after or before performing the series of processes. The wafer 10 may be introduced into the carrier 20 along the transfer path a.

[82] FIG. 3 illustrates processing equipment having a wafer testing apparatus according to a third embodiment of the present invention.

[83] Referring to FIG. 3, a transfer chamber TC is provided in the center, and a plurality of processing chambers PCl, PC2, PC3 and PC4 are placed around the transfer chamber TC. The processing chambers PCl, PC2, PC3 and PC4 communicate with the transfer chamber TC through a gate valve GV.

[84] Further, a transfer robot RB is installed inside the transfer chamber TC so as to pick up the wafer 10 such as a glass substrate and introduce or take out the wafer into or from the plurality of processing chambers PCl, PC2, PC3 and PC4 in sequence.

[85] Also, the transfer chamber TC connects with at least one load lock chamber LLCl,

LLC2. The load lock chamber LLCl, LLC2 serves as a space where the wafer 10 to be transferred is on standby before being transferred to the transfer chamber TC.

[86] Meanwhile, the load lock chamber LLCl, LLC2 is connected to and communicates with the wafer testing apparatus A. The wafer testing apparatus A forms the transfer path a through which the wafer 10 is transferred to the load lock chamber LLCl, LLC2.

[87] Therefore, the wafer 10 may be introduced into the load lock chamber LLCl, LLC2 along the transfer path a. Further, the wafer testing apparatus A forms another transfer path c through which the wafer is taken out toward a predetermined position.

[88] FIG. 4 is a plan view illustrating a layout of an inspector and a conveyer-type wafer carrier in the wafer testing apparatus according to an embodiment of the present invention. FIGS. 5 and 6 illustrate a wafer testing apparatus according to an embodiment of the present invention.

[89] Below, the wafer testing apparatus according to an embodiment of the present invention shown in FIGS. 1, 2 and 3 will be described with reference to FIGS. 4 through 6.

[90] As shown in FIG. 5, the wafer testing apparatus A includes the wafer transferring part 500 to transfer the wafer 10 to the processing chamber PC in FIG. 1, the carrier 20 in FIG. 2 or the load lock chamber LLCl, LLC2 in FIG. 3 along the transfer path a; and the inspector 600 that is placed near an edge of the wafer 10, inspects where a crack or a particle exists in the edge of the wafer 10, distinguishes the crack from the particle, and takes out the wafer 10 toward another transfer path c when the crack exists. [91] Referring to FIGS. 4 and 5, the wafer transferring part 500 is type of a conveyer by way of example. [92] The wafer transferring part 500 includes a conveyer 511 on which the wafer 10 is put and carried, and rollers 512 which move the conveyer 511 along the transfer path a. [93] Alternatively, the wafer transferring part 500 may be achieved by a different device as long as it can transfer the wafer 10 along the transfer path a. [94] According to an aspect of the invention, the inspector 600 may include a first inspector 610 and a second inspector 620. [95] Alternatively, each inspector 600 may include the first inspector 610 or the second inspector 620 individually. [96] Further, the inspector 600 may include a transferring unit 640. Here, the transferring unit 640 may be a kind of transferring device such as a robot arm or a gripper, which can pick up the wafer 10 and take it out along another transfer path c. [97] In detail, configurations of the inspector 600 are as follows.

[98] As shown in FIG. 4, the first inspector 610 is placed in the vicinity of the edge of the wafer 10. Further, the second inspector 620 is placed at a lateral side or over the transfer path a of the wafer 10. [99] FIG. 5 illustrates the wafer testing apparatus according to an embodiment of the present invention. FIG. 6 shows a different layout of an integrating body in FIG. 5. [100] Referring to FIG. 5, the first inspector 610 includes a first laser generator 611 placed below the edge of the wafer 10 and emitting a laser and a first inspecting module, and a photographing module 612. [101] The first inspecting module be placed above the edge of the wafer 10, receiving the incident laser passed through the edge of the wafer 10. Thus, light quantity of the laser that exits toward a side corresponding to an incident position is detected, so that it is possible to determine whether the crack or the particle exists in the edge of the wafer

10 and to distinguish the crack and the particle from each other. [102] The photographing module 612 may be placed above or below the wafer 10, and include a light source 612a illuminating one side of the wafer 10, and a camera 612b photographing one side of the wafer 10 illuminated by the light source 612a. [103] For example, the light source 612a may be placed below the wafer 10, and the camera 612b may be placed above the wafer 10. [104] Alternatively, referring to FIG. 6, the first laser generator 611 may be placed above the edge of the wafer 10, and the first inspecting module may be placed below the edge of the wafer 10.

[105] Here, the first inspecting module shown in FIGS. 5 and 6 is an integrating body having a cylindrical shape. Alternatively, the first inspecting module may be an integrating sphere.

[106] The integrating body is placed below the edge of the wafer 10, and detects the light quantity of the laser that passes through the edge of the wafer 10, is incident thereto and exits toward the side corresponding to the incident position, thereby determining whether the crack or the particle exists in the edge of the wafer 10 and distinguishing the crack and the particle from each other.

[107] Configurations of the integrating body and the integrating sphere will be described below.

[108] FIG. 7 illustrates a wafer testing apparatus according to another embodiment of the present invention, and FIG. 8 shows a different layout of an optical system in FIG. 7.

[109] Referring to FIGS. 7 and 8, the first inspecting module may be an optical system 700 that includes a condenser lens 710 to condense the laser, and a photodiode 720 placed in the vicinity of the condenser lens 710 so as to be disposed on the condensing path and detecting the light quantity of the condensed laser.

[110] The first inspecting module may be placed above the wafer 10 as shown in FIG. 7, or below the wafer 10 as shown in FIG. 8.

[I l l] FIG. 9 shows the second inspector in FIG. 5. FIG. 10 illustrates an operation of the second inspector of FIG. 9. FIG. 11 is a bottom view of a photodiode structure according to an embodiment of the present invention. FIG. 12 illustrates another operation of the second inspector of FIG. 9.

[112] Referring to FIG. 9, the second inspector 620 includes a second laser generator placed at a lateral side of the wafer 10 to be transferred and emitting a laser along a lengthwise direction of the wafer 10, and a vertically-movable cylinder 622 connected to the second laser generator 621 and vertically moving an illuminating position of the laser to a predetermined position, and a second inspecting module placed over the wafer 10 and detecting the laser scattered by the wafer 10.

[113] The second inspecting module may be a photodiode structure 623.

[114] Referring to FIGS. 9 and 11, the photodiode structure 623 includes a supporting rod 623a forming a predetermined length along a direction transverse to a moving direction of the wafer 10, and a plurality of photodiodes 623b placed below the supporting rod 623a.

[115] The photodiodes 623b each have a circular shape and are arranged zigzag. There may be no space between the photodiodes 623b.

[116] Meanwhile, the transferring unit 640 may be a gripper placed at the lateral side of the wafer 10, and the integrating body and the photodiode structure 623 may be elec- trically connected to each other. Thus, when the crack or the particle exists in the edge of the wafer 10 or when the photodiode structure 623 detects the laser, the transferring unit 640 receives driving power from the outside and takes out the wafer 10 to a certain position along another transfer path c.

[117] The second inspecting module may employ the above-mentioned integrating body that can detect the laser scattered by the crack or the particle in the wafer 10.

[118] The first and second inspectors 610 and 620 and the transferring unit 640 are electrically connected to a main controller 650.

[119] Below, configurations of the integrating body employed as the first inspecting module of the first inspector 610 and the second inspecting module of the second inspector 620 will be described in detail.

[120] FIG. 13 is a perspective view of an integrating body according to an embodiment of the present invention. FIG. 14 is a cross-sectional view taken along line I-I of FIG. 13. FIG. 15 is a cross-sectional view showing another example of an inner space of the integrating body of FIG. 13. FIG. 16 is a block diagram of a monitoring module of FIG. 13.

[121] The integrating body improved according to an embodiment of the present invention is as follows.

[122] Referring to FIG. 13, the integrating body according to an embodiment of the present invention includes a body 100 and a first optical detector 300.

[123] The body 100 includes a light incident part 110 to which light such as a laser is incident, a light exit part 120 provided at a side corresponding to the light incident part 110, and a diffused- light exit part 130 provided between the light incident part 110 and the light exit part 120 and allowing the light incident to the light incident part 110 and diffused to exit. Further, the body 100 has a predetermined inner space.

[124] The light incident part 110 and the light exit part 120 are achieved by holes each having a predetermined length along a longitudinal direction of the body 100.

[125] The body 100 has a cylindrical shape. The inner space of the body 100 is exposed through the light incident part 110.

[126] Here, the inner space of the body 100 may have a cylindrical shape as shown in FIG. 13. Alternatively, as shown in FIG. 14, the inner space of the body 100 may have a first space Sl having a cylindrical shape and second spaces S2 each having a hemispherical shape and positioned at opposite sides of the first space Sl, in which the first space S 1 communicates with the second spaces S2.

[127] The diffused-light exit part 130 includes a plurality of through holes nonlinearly arranged along the longitudinal direction of the body 100, each hole having a circular or elliptical shape. Alternatively, each hole may have a polygonal shape. The diffused- light exit part 130 communicates with the inner space of the body 100. Through the diffused light exiting part 130, the light incident to the light incident part 110 and diffused through the inner space of the body 100 exits.

[128] According to an embodiment of the present invention, the first optical detector 300 is provided in the diffused- light exit part 130, and detects the quantity of light that is incident to the light incident part 110, is diffused through the inner space of the body 100 and exits through the diffused- light exit part 130.

[129] The first optical detector 300 is electrically connected to a monitoring module 400.

[130] Referring to FIG. 16, the monitoring module 400 includes a controller 410 electrically connected to the first optical detector 300, and a display 420 electrically connected to the controller 410.

[131] The controller 410 is installed in the body 100 as being electrically connected to an optical detector 200, and determines whether the detected light quantity is within a preset reference light quantity range.

[132] Here, the reference light quantity range includes a first reference light quantity range for distinguishing the crack, and a second reference light quantity range for distinguishing the particle.

[133] The display 420 is installed in the body 100 and electrically connected to the controller 410, so that it can visually display the reference light quantity range for presetting the light quantity and visually display whether the detected light quantity is within the preset reference light quantity.

[134] FIG. 17 is a perspective view of an integrating body according to another embodiment of the present invention. FIG. 18 is a cross-sectional view of the integrating body of FIG. 17. FIG. 19 is a block diagram of a monitoring module of FIG. 17.

[135] Referring to FIG. 17, the integrating body according to another embodiment of the present invention includes a body 100, a first optical detector 300 and a second optical detector 200.

[136] Here, the first optical detector 300 is the same as that described above, and the second optical detector 200 detects the light quantity of light that is incident to the light incident part 110 and exits from the inside of the body 100 to the light exit part 120.

[137] The first and second optical detectors 300 and 200 may be each achieved by a photodiode. The photodiode serves for transforming optical energy into electrical energy, thereby detecting the quantity of the light.

[138] The first and second optical detectors 300 and 200 are connected to the monitoring module 400.

[139] In more detail, the integrating body shown in FIG. 17 includes a body 100 that has the light incident part 110, the light exit part 120 provided at a side corresponding to the light incident part 110, and the diffused- light exit part 130 provided between the light incident part 110 and the light exit part 120 and allowing the light incident to the light incident part 110 and diffused to exit, and forms a predetermined inner space; a detachable body 150 that has a third space S3 fitted to the inner space of the body 100 in parallel and having a predetermined length, and a fourth space S4 provided at opposite sides of the third space S3, having a hemispherical shape and communicating with the third space S3, an auxiliary light incident part 111, an auxiliary light exit part 121 and an auxiliary diffused-light exit part 131 so that the third and fourth spaces S3 and S4 communicate with the light incident part 110 and the light exit part 120; the second optical detector 200 that detects the quantity of the light incident to the light incident part 110 and exiting to the light exit part 120; and the first optical detector 300 that is provided in the diffused-light exit part 130 and detects the quantity of the diffused exit light.

[140] Here, the first optical detector 300 and the second optical detector 200 include the photodiodes. The second optical detector 200 is substantially the same as that of FIG. 12. In the case of the first optical detector 300, the photodiode is fitted to the circular or elliptical through hole of the diffused-light exit part 130.

[141] Referring to FIG. 19, the first and second optical detector 300 and 200 are electrically connected to the monitoring module 400.

[142] The monitoring module 400 further includes a selector 430 for selectively switching the first and second optical detectors 300 and 200.

[143] Thus, the first and second optical detectors 300 and 200 are electrically connected to the selector 430, and the selector 430 is electrically connected to the controller 410. Further, the controller 410 is electrically connected to the display 420.

[144] The controller 410 and the display 420 are provided on an outer circumference of the body 100.

[145] Referring to FIG. 18, the detachable body 150 includes a third space S3 fitted to the inner space of the body 100 in parallel and having a predetermined length, and a fourth space S4 provided at opposite sides of the third space S3, having a hemispherical shape and communicating with the third space S3, an auxiliary light incident part 111 and an auxiliary light exit part 121 so that the third and fourth spaces S3 and S4 communicate with the light incident part 110 and the light exit part 120.

[146] Here, a cap body 101 shaped like a cap is provided at one side of the body 100 and screw-coupled to the one side of the body 100.

[147] The body 100 and the cap body 101 each have a cylindrical inner space.

[148] In addition, a guide projection (not shown) may be formed on an inner wall of the body 100, and a guide hole (not shown) may be formed on an outer circumference of the detachable body 150 and gliding on the guide projection.

[149] FIG. 20 is a cross-sectional view showing another example of an integrating body according to a third embodiment of the present invention. [150] In the meantime, the foregoing integrating body has a cylindrical shape corresponding to the body 100 shaped like a cylinder having a predetermined length.

[151] Alternatively, the integrating body employed as the first inspecting module for the first inspector 610 may have the integrating sphere as shown in FIG. 19.

[152] The integrating sphere includes a spherical body 102 forming a predetermined inner space, a light incident part 111 formed at one side of the body 102, a light exit part 121 formed at the other side of the body 102 corresponding to the light incident part 111, and a diffused- light exit part 131 formed in the body 102 between the light incident part 111 and the light exit part 121.

[153] As described above, the first optical detector 300 may be installed in the diffused- light exit part 131, or both the second and first optical detectors 200 and 300 may be installed in the optical incident part 111 and the diffused-light exit part 131, respectively.

[154] In addition, the first optical detector 300 and the second optical detector 200 may be electrically connected to the controller 410 as shown in FIGS. 15 and 18. Further, the controller 410 is electrically connected to the main controller 650.

[155] Meanwhile, processing equipment having the wafer testing apparatus with the foregoing configuration operates as follows.

[156] The wafer 10 shown in FIGS. 1, 2 and 3 is transferred by the wafer transferring part 500 such as a roller to the inside of the wafer testing apparatus A along the transfer path a.

[157] Referring to FIGS. 4 and 6, the wafer 10 transferred along the transfer path a is inspected by the inspector 600. Here, the inspector 600 inspects whether the crack or the particle exists in the edge part, the inside and the top surface of the wafer 10 and distinguishes the crack and the particle from each other. Also, an outer state of the wafer 10 may be checked visually.

[158] First, a process of inspecting the edge part of the wafer 10 with the first inspector 610 will be described.

[159] Referring to FIG. 5, the transferring unit 640 transfers the wafer 10 to a certain position.

[160] Then, the first laser generator 611 emits the laser from bottom to top of the wafer 10. In FIG. 6, the first laser generator 611 emits the laser from below to the bottom of the wafer.

[161] The laser passed through the wafer 10 is incident to the light incident part 110 of the integrating body.

[162] In other words, the laser is incident from the light incident part 110 to the inner space of the body 100 while forming a travelling path.

[163] Then, the light reaches the light exit part 120 opposite to the light incident part 110 along the travelling path.

[164] Thus, the first and second optical detectors 300 and 200 with the plurality of pho- todiodes arranged in parallel with the light exit part 120 are capable of detecting the quantity of the light. Then, the first and second optical detectors 300 and 200 send the detected quantity of the light to the controller 410.

[165] The controller 410 determines whether the detected quantity of the light is within the preset reference light quantity range.

[166] When the quantity of the light is detected, the controller 410 determines that the crack or the particle exists in the wafer 10.

[167] Further, the controller 410 determines that the crack exists when the detected quantity of the light is within the reference light quantity range, particularly, within the first reference light quantity range. On the other hand, when the detected quantity is within the second reference light quantity range, the controller 410 determines that the particle exists. Then, the controller 410 sends determination results to the main controller 650.

[168] Also, an electrical signal is sent to the display 420 so that the reference light quantity range can be visually displayed and it can be visually displayed whether the detected light quantity is within the preset reference light quantity range.

[169] Accordingly, it can be visually and easily recognized through the display 420 whether the quantity of the light, incident to the light incident part 110 and exiting from the light exit part 120, detected by the optical detector 200, is within the reference light quantity range.

[170] Meanwhile, if the light incident to the light incident part 110 is diffused in the inner space of the body 100, the diffused light exits through the diffused- light exit part 130 provided in the body 100.

[171] At this time, the light diffused inside the body 100 is reflected from the inner wall of the second space S2 having the hemispherical shape, and thus easily guided toward the diffused- light exit part 130.

[172] In addition, the photographing module 612 photographs the top surface of the wafer 10.

[173] For example, the light source 612a illuminates the bottom of the wafer 10. Then, the camera 612b placed above the wafer 10 photographs the illuminated top surface of the wafer 10, and sends information about a photographed image to the main controller 650.

[174] Accordingly, the main controller 650 may store the information about the photographed image for visually checking a state of the top surface of the wafer 10.

[175] In the meantime, operations of another integrating body employed in the first inspector 610 will be described below. [176] The quantity of the laser incident to the light incident part 110 and travelling is detected by the second optical detector 200 provided in the light exit part 120.

[177] Further, the quantity of the light diffused in the inner space of the body 100 or the detachable body 150 is detected by the first optical detector 300 provided in the diffused- light exit part 130.

[178] At this time, the selector 430 electrically connects the controller 410 with at least one of the second optical detector 200 and the first optical detector 300.

[179] If both the second optical detector 200 and the first optical detector 300 are connected to the controller 410, the second optical detector 200 and the first optical detector 300 may send the quantity of the light and the quantity of the diffused-light to the controller 410, respectively.

[180] Then, the controller 410 determines whether the detected quantity of the light is within the reference light quantity range, and determines whether the detected quantity of the diffused light is within a reference diffused-light quantity range.

[181] In the case that the detected quantity of the diffused light is within the reference diffused-light quantity range, particularly when the detected quantity of the diffused light is within the first reference light quantity range, the controller 410 determines that the crack exists. On the other hand, when the detected quantity of the diffused light is within the second reference light quantity range, the controller 410 determines that the particle exists.

[182] Further, the controller 410 visually displays the detected quantity of the light, the preset reference light quantity range, the detected quantity of the diffused light, and the preset reference diffused-light quantity range. Also, the controller 410 displays whether the detected quantity of the light is within the preset reference light quantity range, and whether the detected quantity of the diffused light is within the preset reference diffused-light quantity range.

[183] Accordingly, when the quantity of the light detected by the second optical detector 200 is beyond the reference light quantity range or when the quantity of the diffused light is beyond the reference diffused-light quantity range, it is regarded that the crack or the particle exists in the edge of the wafer 10. Here, the method of distinguishing the crack and the particle from each other is the same with that described above, and thus repetitive descriptions will be omitted.

[184] Through the display 420, it can be visually and easily recognized whether the quantity of the light, incident to the light incident part 110 and exiting from the light exit part 120, detected by the optical detector 200, is within the reference light quantity range and whether the quantity of the diffused-light is within the reference diffused- light quantity range.

[185] As mentioned above, if the crack or the particle exists in the wafer 10, the controller 410 sends an electrical signal to the main controller 650, and controls the transferring unit 640 to pick up the wafer 10 and takes it out along another transfer path c as shown in FIGS. 1 through 3.

[186] On the other hand, if the detected quantity of the light is within the reference light quantity range of if the detected quantity of the diffused-light is within the reference diffused- light quantity range, the controller 410 determines that there is no crack or particle in the edge of the wafer 10, so that the wafer 10 is introduced into the processing chamber PC of FIG. 1, a carrier 20 of FIG. 2 and the load lock chamber LLCl, LLC2 of FIG. 3 along the transfer path a. Accordingly, the wafer 10 is introduced into the transfer chamber TC and the plurality of processing chambers PCl, , PC4, thereby undergoing the series of processes.

[187] Next, operations of the second inspector 620 according to an embodiment of the present invention will be described below.

[188] Referring to FIGS. 5 and 6, the main controller 650 sends a signal to a driver 660 and the driver 660 adjusts a vertical position of the vertically-movable cylinder 622, thereby changing a setting position of the second laser generator 621.

[189] At the setting position, the laser emitted as a line beam from the second laser generator 621 travels along the top surface of the wafer 10 or penetrates the wafer 10 along the lengthwise direction.

[190] FIG. 10 shows the former case in which the laser travelling along the top surface of the wafer 10 is scattered and reflected by the particle existing on the top surface and then detected by the photodiode structure 623 as the second inspecting module placed above the wafer 10. Thus, the photodiode structure 623 detects a predetermined quantity of light.

[191] In this case, the photodiodes 623b of the photodiode structure 623 send the electrical signal to the main controller 650, and the main controller 650 drives the transferring unit 640 to take out the wafer 10 to the outside along another transfer path c.

[192] FIG. 12 shows the latter case in which the laser passing through the wafer 10 along the lengthwise direction of the wafer 10 is diffused and reflected by a foreign material formed in the wafer 10 and then detected by the photodiodes 623b placed above the wafer 10.

[193] In this case, the photodiodes 623b send the electrical signal to the main controller 650, and the main controller 650 drives the transferring unit 640 to take out the wafer 10 to the outside along another transfer path c.

[194] In the case where the cylindrical integrating body is used as the second inspecting module, if the light scattered from the wafer 10 is detected by the first optical detector 300 of the diffused-light exit part 130 and the second optical detector 200 of the light exit part 120, the controller 410 determines that the crack or the particle exists in the wafer 10, thereby taking the wafer 10 out as described above. Here, the method of distinguishing the crack and the particle from each other is the same with that as described above.

Claims

[1] A wafer testing apparatus comprising: a wafer transferring part which transfers a wafer along a transfer path; and an inspector which is placed near an edge of the wafer to be transferred, inspects whether a crack or a particle exists in the edge of the wafer, and distinguishes between the crack and the particle.

[2] The wafer testing apparatus according to claim 1, wherein the inspector comprises a first inspector and a second inspector, the first inspector comprising a first laser generator placed below the edge of the wafer and emitting a laser, a first inspecting module placed above the edge of the wafer and determining whether the crack or the particle exists in the edge of the wafer and distinguishing between the crack and the particle by detecting quantity of the laser passing through the edge of the substrate, incident to and exiting from an opposite side, and a photographing module photographing an outer surface of the wafer, and the second inspector comprising a second laser generator placed at a lateral side of the wafer to be transferred and emitting a laser along a lengthwise direction of the wafer, a vertically-movable cylinder connected to the second laser generator and vertically moving an illumination position of the laser to a certain position, and a second inspecting module placed above the wafer and detecting the laser scattered from the wafer.

[3] The wafer testing apparatus according to claim 2, wherein the inspector comprises a transferring unit, the transferring unit being electrically connected to the first and second inspecting modules and taking out the wafer toward another transfer path when the crack exists in the wafer or when the second inspecting module detects the laser.

[4] The wafer testing apparatus according to claim 2, wherein the first inspecting module is an integrating body that comprises a body comprising a light incident part, a light exit part opposite to the light incident part, and a diffused-light exit part placed between the light incident part and the light exit part and allowing the light incident to the light incident part to be diffused and exit, and forming a predetermined inner space, a first optical detector provided in the diffused-light exit part and detecting the quantity of the diffused-light, a second optical detector provided in the light exit part and detecting the quantity of the light incident to the light incident part and exiting through the light exit part, and a monitoring module electrically connected to the first and second optical detectors and determining whether the crack or the particle exists and distinguishing between the crack and the particle on the basis of the detected light quantity, and the photographing module comprises a light source placed in one side of the wafer and illuminating the wafer, and a camera placed in the other side of the wafer and photographing the outer surface of the wafer.

[5] The wafer testing apparatus according to claim 2, wherein the first inspecting module is an optical system that comprises a lens placed in the vicinity of the wafer and condensing the laser, and a photodiode placed in the vicinity of the lens and detecting the quantity of the laser.

[6] The wafer testing apparatus according to claim 4, wherein the body has a cylindrical shape.

[7] The wafer testing apparatus according to claim 2, wherein the second inspecting module is placed above the wafer and comprises a plurality of photodiodes.

[8] The wafer testing apparatus according to claim 2, wherein the second inspecting module is an integrating body that comprises a body comprising a light incident part, a light exit part opposite to the light incident part, and a diffused-light exit part placed between the light incident part and the light exit part and allowing the light incident to the light incident part to be diffused and exit, and forming a predetermined inner space, a first optical detector provided in the diffused-light exit part and detecting the quantity of the diffused-light, a second optical detector provided in the light exit part and detecting the quantity of the light incident to the light incident part and exiting through the light exit part, and a monitoring module electrically connected to the first and second optical detectors and determining whether the crack or the particle exists and distinguishing between the crack and the particle on the basis of the detected light quantity.

[9] The wafer testing apparatus according to claim 4, wherein the inner space comprises a first space having a predetermined length and formed in parallel, and second spaces placed at opposite sides of the first space, having a hemispherical shape and communicating with the first space, and the first and second spaces communicate with the light incident part and the light exit part.

[10] The wafer testing apparatus according to claim 4, wherein the light incident part and the light exit part each comprise a hole having the same length and linearly formed along the lengthwise direction of the body, and the diffused-light exit part comprises a plurality of through holes nonlinearly formed along the lengthwise direction of the body.

[11] The wafer testing apparatus according to claim 4, wherein the body comprises a detachable body to be fitted to the inner space, the detachable body comprising a third space having a predetermined length and formed in parallel; fourth spaces provided at opposite sides of the third space, having a hemi-spherical shape and communicating with the third space; and an auxiliary light incident part and an auxiliary light exit part through which the third and fourth spaces communicate with the light incident part and the light exit part.

[12] The wafer testing apparatus according to claim 4, wherein the first optical detector and the second optical detector comprise photodiodes.

[13] The wafer testing apparatus according to claim 4 or 8, wherein the monitoring module comprises: a controller installed in the body, electrically connected to the first and second optical detectors, determining whether the detected quantity of the light is within a reference light quantity range, determining whether the detected quantity of the diffused-light is within a reference diffused-light quantity range, determining whether the crack or the particle exists, and distinguishing between the crack and the particle; and a display installed in the body, electrically connected to the controller, visually displaying the reference light quantity range preset for the detected quantity of the light, visually displaying whether the detected quantity of the light is within the reference light quantity range, visually displaying the reference diffused-light quantity range preset for the detected quantity of the diffused-light, and visually displaying whether the detected quantity of the diffused-light is within the reference diffused-light quantity range, wherein the reference light quantity range comprises a first reference light quantity range for distinguishing the crack, and a second reference light quantity range for distinguishing the particle, and wherein the reference diffused-light quantity range comprises a first reference diffused-light quantity range for distinguishing the crack, and a second reference diffused-light quantity range for distinguishing the particle.

[14] Processing equipment having a wafer testing apparatus, comprising: a chamber internally formed with a transfer path for a wafer; a wafer transferring part placed close to the chamber and transferring the wafer to the chamber along the transfer path; and a wafer testing apparatus comprising an inspector which is placed near an edge of the wafer to be transferred, inspects whether a crack or a particle exists in the edge of the wafer, distinguishes between the crack and the particle, and takes out the wafer along another transfer path.

[15] The processing equipment according to claim 14, wherein the inspector comprises a first inspector and a second inspector, the first inspector comprising a first laser generator placed below the edge of the wafer and emitting a laser, a first inspecting module placed above the edge of the wafer and determining whether the crack or the particle exists in the edge of the wafer and distinguishing between the crack and the particle by detecting quantity of the laser passing through the edge of the substrate, incident to and exiting from an opposite side, and a photographing module photographing an outer surface of the wafer, and the second inspector comprising a second laser generator placed at a lateral side of the wafer to be transferred and emitting a laser along a lengthwise direction of the wafer, a vertically-movable cylinder connected to the second laser generator and vertically moving an illumination position of the laser to a certain position, and a second inspecting module placed above the wafer and detecting the laser scattered from the wafer.

[16] The processing equipment according to claim 15, wherein the inspector comprises a transferring unit, the transferring unit being electrically connected to the first and second inspecting modules and taking out the wafer toward another transfer path when the crack exists in the wafer or when the second inspecting module detects the laser.

[17] The processing equipment according to claim 15, wherein the first inspecting module is an integrating body that comprises a body comprising a light incident part, a light exit part opposite to the light incident part, and a diffused-light exit part placed between the light incident part and the light exit part and allowing the light incident to the light incident part to be diffused and exit, and forming a predetermined inner space, a first optical detector provided in the diffused-light exit part and detecting the quantity of the diffused-light, a second optical detector provided in the light exit part and detecting the quantity of the light incident to the light incident part and exiting through the light exit part, and a monitoring module electrically connected to the first and second optical detectors and determining whether the crack or the particle exists and distinguishing between the crack and the particle on the basis of the detected light quantity, and the photographing module comprises a light source placed in one side of the wafer and illuminating the wafer, and a camera placed in the other side of the wafer and photographing the outer surface of the wafer.

[18] The processing equipment according to claim 15, wherein the first inspecting module is an optical system that comprises a lens placed in the vicinity of the wafer and condensing the laser, and a photodiode placed in the vicinity of the lens and detecting the quantity of the laser.

[19] The processing equipment according to claim 17, wherein the body has a cylindrical shape.

[20] The processing equipment according to claim 15, wherein the second inspecting module is a photodiode structure that comprises a supporting rod provided above the wafer and having a predetermined length along a direction transverse to a moving direction of the wafer, and a plurality of photodiodes placed below the supporting rod and facing a top surface of the wafer, and the photodiodes each have a circular shape and are arranged in a zigzag pattern.

[21] The processing equipment according to claim 15, wherein the second inspecting module is an integrating body that comprises a body comprising a light incident part, a light exit part opposite to the light incident part, and a diffused-light exit part placed between the light incident part and the light exit part and allowing the light incident to the light incident part to be diffused and exit, and forming a predetermined inner space, a first optical detector provided in the diffused-light exit part and detecting the quantity of the diffused-light, a second optical detector provided in the light exit part and detecting the quantity of the light incident to the light incident part and exiting through the light exit part, and a monitoring module electrically connected to the first and second optical detectors and determining whether the crack or the particle exists and distinguishing between the crack and the particle on the basis of the detected light quantity.

[22] The processing equipment according to claim 17, wherein the inner space comprises a first space having a predetermined length and formed in parallel, and second spaces placed at opposite sides of the first space, having a hemispherical shape and communicating with the first space, and the first and second spaces communicate with the light incident part and the light exit part.

[23] The processing equipment according to claim 17, wherein the light incident part and the light exit part each comprise a hole having the same length and linearly formed along the lengthwise direction of the body, and the diffused-light exit part comprises a plurality of through holes nonlinearly formed along the lengthwise direction of the body.

[24] The processing equipment according to claim 17, wherein the body comprises a detachable body to be fitted to the inner space, the detachable body comprising a third space having a predetermined length and formed in parallel; fourth spaces provided at opposite sides of the third space, having a hemi-spherical shape and communicating with the third space; and an auxiliary light incident part and an auxiliary light exit part through which the third and fourth spaces communicate with the light incident part and the light exit part.

[25] The processing equipment according to claim 17, wherein the first optical detector and the second optical detector comprise photodiodes.

[26] The processing equipment according to claim 17 or 21, wherein the monitoring module comprises: a controller installed in the body, electrically connected to the first and second optical detectors, determining whether the detected quantity of the light is within a reference light quantity range, determining whether the detected quantity of the diffused-light is within a reference diffused-light quantity range, determining whether the crack or the particle exists, and distinguishing between the crack and the particle; and a display installed in the body, electrically connected to the controller, visually displaying the reference light quantity range preset for the detected quantity of the light, visually displaying whether the detected quantity of the light is within the reference light quantity range, visually displaying the reference diffused-light quantity range preset for the detected quantity of the diffused-light, and visually displaying whether the detected quantity of the diffused-light is within the reference diffused-light quantity range, wherein the reference light quantity range comprises a first reference light quantity range for distinguishing the crack, and a second reference light quantity range for distinguishing the particle, and wherein the reference diffused-light quantity range comprises a first reference diffused-light quantity range for distinguishing the crack, and a second reference diffused-light quantity range for distinguishing the particle.