JPH0514903U - Foreign matter inspection device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a foreign matter inspection device which has a simple configuration and control and can reliably perform an inspection without being affected by stray light even when the pellicle frame has a circular shape. [Structure] Near the slit 10, a slit 10 is formed by a heart cam 21 that rotates in response to a change in the scanning position of the laser light L.
A slit mask member 13 which is linearly displaced in the longitudinal direction is provided so that the effective light transmission length of the slit 10 is adjusted.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is mainly applied to a reticle or mask used for printing a circuit pattern on a semiconductor wafer in a LSI manufacturing process, or a product wafer on which a circuit pattern is formed, and a surface of an inspection target substrate such as a liquid crystal substrate. In addition, the present invention relates to a foreign matter inspection device capable of specifying whether or not a foreign matter is attached and the size and place of the foreign matter.

[0002]

[Prior Art]

 FIG. 4 shows a main part configuration of a conventional foreign matter inspection apparatus. In this figure, reference numeral 1 is a substrate to be inspected on which a circuit pattern (not shown) is drawn on a surface, which is on an inspection stage (not shown). It is placed horizontally, and the pellicle frame 2 is provided on the surface thereof. The inspection stage 1 is designed so as to be slidable in the arrow X direction and the arrow Y direction orthogonal thereto in the drawing.

Reference numeral 3 denotes an incident optical system for irradiating the surface of the substrate 1 to be inspected with the laser light L while scanning it linearly in the direction of the arrow X. For example, the laser light L having a constant deflection angle is emitted. A He-Ne laser oscillator 4, a beam expander 5, for example, a galvanometer mirror, and an optical scanning mirror 6 that rotates in the direction of arrow UV to scan the laser light L, and a condenser lens 7 and the like. The laser beam L from the laser oscillator 4 is configured to irradiate the substrate 1 to be inspected from a diagonally upper direction at a predetermined angle within a predetermined range in the X direction while performing reciprocal linear scanning as shown by a double-headed arrow. .

Reference numeral 8 denotes a detection optical system for detecting the reflected and scattered light R from the irradiation surface of the laser light L radiated to the inspection target substrate 1, which is arranged diagonally above both sides of the inspection target substrate 1 in the X direction. Each of these detection optical systems 8 includes a condenser lens 9, a slit member 11 having an elongated slit 10 for limiting incident light with respect to reflected scattered light, and a photodetector 12 including, for example, a photomultiplier tube. Consists of.

In the foreign matter inspection apparatus thus configured, the laser beam L from the laser oscillator 4 is moved obliquely upward from the inspection target substrate 1 by a predetermined angle while the inspection stage is linearly moved in the arrow Y direction. In addition, irradiation is performed while reciprocating linearly scanning within a predetermined range in the X direction, and the reflected scattered light R from the surface of the inspection target substrate 1 at that time is made incident on the photodetector 12. When a foreign substance is present on the surface of the reciprocating inspection target substrate 1, the laser light L radiated on the surface of the inspection target substrate 1 is randomly scattered in all directions by the foreign substance, and the reflected scattered light R is radiated to the side. The presence of the foreign matter on the surface of the inspection target substrate 1 can be detected by the detection by the photodetector 12 located on one side.

[0006]

[Problems to be solved by the device]

 However, the above-described conventional foreign matter inspection apparatus has the following drawbacks. That is, the detection optical system 8 is configured by adopting a means of providing a slit member 11 having a slit 10 for the reflected scattered light R in front of the photodetector 12 in order to reduce the influence of stray light. However, it was not always possible to reliably eliminate the effects of stray light with such a fixed slit method.

The sizes of the inspection target substrate 1 and the pellicle frame 2 formed on the surface of the inspection target substrate 1 are various, and depending on the sizes of the inspection target substrate 1 and the pellicle frame 2, an example is shown in FIG. As described above, the projection image of the slit 10 sometimes overlaps with the pellicle frame 2. In such a case, the reflected and scattered light R from the pellicle frame 2 enters the detection optical system 8 as stray light and is erroneously detected as the presence of foreign matter.

In other words, in the foreign matter inspection device having the above-described conventional configuration, a portion near the pellicle frame 2 is greatly affected by stray light and thus has a limit in foreign matter detection performance, and accordingly, a foreign matter detectable area is also limited. (Specifically, it was possible to inspect only the area 2 to 3 mm away from the pellicle frame 2).

As a means for solving such a problem, for example, as disclosed in Japanese Patent Application Laid-Open No. 1-129144, a rotary slit is provided immediately before or after a slit member, and the rotary slit is provided at a scanning position of a laser beam. It has been proposed that the slit of the slit member can be further appropriately restricted by rotationally displacing it according to the change of

However, the device disclosed in this publication has a drawback that the mechanism for rotating the rotary slit is complicated and the control system thereof is complicated.

The present invention has been made in consideration of the above matters, and its purpose is to be simple in configuration and control, and even if the pellicle frame is circular, it is not affected by stray light. It is to provide a foreign matter inspection device capable of surely inspecting.

[0012]

[Means for Solving the Problems]

 In order to achieve the above object, the foreign matter inspection apparatus according to the present invention is provided with a slit mask member near the slit, which is linearly displaced in the longitudinal direction of the slit by a heart cam that rotates according to a change in the scanning position of laser light. , The slit's effective light transmission length is adjusted.

[0013]

[Action]

 With a heart cam that rotates in response to changes in the scanning position of the laser light emitted from the laser oscillator, the slit mask member can be linearly displaced in the longitudinal direction of the slit to determine the effective light transmission length of the slit. It is possible to adjust the light irradiation position according to the excess or deficiency. Furthermore, since a heart cam that converts circular motion into linear motion is used, it is possible to reliably prevent the effect of stray light even if the pellicle frame is circular, thus significantly improving the foreign matter detection performance. Moreover, it is possible to reliably inspect an area very close to the pellicle frame without being affected by stray light.

[0014]

Embodiment An embodiment of the present invention will be described below with reference to the drawings. In the following description, the same symbols as those shown in FIGS. 4 and 5 indicate the same items.

FIG. 1 shows a foreign matter inspection apparatus according to one embodiment. In this figure, 13 is a slit mask member provided near the slit 10. The configuration around the slit mask member 13 and the slit 10 will be described with reference to FIG.

As shown in FIG. 2, the slit member 11 in which the slit 10 is formed is fixed to a fixed base 14 in which an elongated opening (not shown) corresponding to the slit 10 is formed. A guide member 15 provided along the longitudinal direction of the slit 10 and a slide member 16 guided by the guide member 15 are provided on the surface of the fixed base 14 on the slit member 11 side. Reference numeral 17 denotes a roller as a cam follower corresponding to a heart cam 21 described later, which is pivotally attached to the slide member 16.

The slit mask member 13 is held on the rear end side (lower side) by a rod-shaped mounting member 18, which is established on the side of the slide member 16, and together with the slide member 16, the slit mask member 13 moves in the vertical direction (indicated by a double-headed arrow). It can slide linearly in the direction shown). Reference numeral 19 is a spring for constantly pressing and urging the slit mask member 13 against the surface of the slit member 11. Reference numeral 20 is a bearing that holds the tip side (upper side) of the slit mask member 13 so that a slight gap is created between the slit mask member 13 and the surface of the slit member 11.

Next, a mechanism for vertically shifting the slide member 16 (and hence the slit mask member 13) will be described. Reference numeral 21 is a heart-shaped cam in plan view, and one end of this heart cam 21 is It is held by a bearing 22 provided on the fixed base 14, and the other end is fixed to a horizontal shaft 24 held by another bearing 23. A pulley 25 is fixed to the horizontal shaft 24, and is driven by a driving belt 26 such as a timing belt so that the pulley 25 is rotated according to a change in the scanning position of the laser light.

The slit mask member 13 having the above-described configuration is provided in each of the two detection optical systems 8. Then, when the heart cam 21 rotates in response to the change of the scanning position of the laser light L emitted from the laser oscillator 4, the slit mask member 13 moves in the longitudinal direction of the slit 10 as shown in FIG. Is linearly displaced to adjust the effective light transmission length of the slit 10 in correspondence with the irradiation position of the laser light. Therefore, the reflected and scattered light R ′ from the outside of the pellicle frame 2 is prevented from entering the photodetector 12 by the slit mask member 13 as shown by a virtual line, and the influence of stray light is surely blocked. .

In particular, in the present invention, since the heart cam 21 that converts a circular motion into a linear motion is used, even if the pellicle frame 2 has a circular shape, it is possible to reliably prevent the influence of stray light. The foreign matter detection performance can be significantly enhanced, and a region very close to the pellicle frame 2 can be reliably inspected without being affected by stray light.

[0021]

[Effect of the device]

 As described above, according to the present invention, it is possible to reliably prevent stray light from an unnecessary portion other than the irradiation position of laser light from reaching the photodetector. Compared to this, it has far superior foreign matter detection performance, and even with a circular pellicle frame, it is possible to reliably inspect a wider area very close to it without being affected by stray light. In addition, a practical effect is achieved in that the mechanism for driving the slit mask member and the control method are simple.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a main part configuration of a foreign matter inspection device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration near a slit and a slit mask member.

FIG. 3 is an operation explanatory diagram.

FIG. 4 is a diagram schematically showing a main part configuration of a conventional foreign matter inspection device.

FIG. 5 is a diagram for explaining a problem in the detection optical system.

[Explanation of symbols]

1 ... Inspected substrate, 10 ... Slit, 12 ... Photodetector, 13 ...
Slit mask member, 21 ... Heart cam, L ... Laser light,
R ... Reflected scattered light.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H01L 21/66 J 7013-4M

Claims (1)

[Scope of utility model registration request] 1. A photodetector which irradiates a surface of a substrate to be inspected with laser light having a constant deflection angle while scanning, and reflects and scatters light from the surface of the substrate to be inspected at that time through an elongated slit. In the foreign matter inspection device configured to inspect foreign matter on the surface of the substrate to be inspected based on the detection result of the reflected scattered light by the photodetector, in the vicinity of the slit, the scanning position of the laser light. A slit mask member that is linearly displaced in the longitudinal direction of the slit by a heart cam that rotates according to the change of
A foreign matter inspection apparatus characterized in that the effective light transmission length of the slit is adjusted.