JPH10163301A - Alignment apparatus for transparent wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for carrying out the alignment of a transparent wafer by detecting an orientation flat or a notch in a non-contact manner. SOLUTION: The edge part of the lower surface (the surface on which a pattern is not formed) of a transparent wafer 10 held by a pre-chuck 22 is irradiated at a polarization angle with a polarized light from a light emitting part 60. Thus, the polarized light irradiating the lower surface of the transparent wafer 10 is totally reflected to be received by a photodetector 70. If the amount of the light detected by the photodetector 70 is reduced when the transparent wafer is rotated by the pre-chuck 22, the orientation flat or the notch of the transparent wafer 10 is positioned at the part irradiated by the polarized light at that time, so that the orientation flat or the notch can be detected by this reduction of the amount of light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for aligning a transparent wafer, and more particularly to a transparent wafer for aligning a transparent wafer such as glass on which a pattern is recorded in a desired angular direction by detecting an orientation flat or a notch. Related to an alignment apparatus.

[0002]

2. Description of the Related Art Conventionally, a flat orientation flat (orientation flat) or notch notch is formed on a semiconductor wafer to indicate a crystal orientation. In a prober for testing the electrical characteristics of an electronic circuit die such as an IC or an LSI formed on a semiconductor wafer, the orientation direction of the semiconductor wafer is detected by the orientation flat and the notch, and the angle direction is pre-aligned in a predetermined direction. . Note that in the prober, positioning the semiconductor wafer at an approximate angle before placing the semiconductor wafer on the inspection stage is called pre-alignment.

Conventionally, there are several types of pre-alignment methods. At present, an edge portion of a semiconductor wafer is irradiated with a narrow rectangular light beam, the semiconductor wafer is rotated, and the amount of transmitted light is reduced. In general, the pre-alignment is performed by utilizing the change due to the orientation flat or the notch which is a part of the edge portion.

[0004]

However, in the case of a wafer having an opaque member such as a semiconductor wafer, pre-alignment can be performed by the above-described method. However, in the case of a transparent wafer whose material is a transparent member such as glass, an orientation flat is used. The change in the amount of transmitted light due to the pattern and the notch is small, especially when a pattern is formed on the surface of the transparent wafer, the change in the amount of light due to the presence or absence of this pattern greatly affects, and it is difficult to detect the orientation flat and the notch with the above method. It is.

For this reason, a method called mechanical pre-alignment in which a roller is pressed against the edge of a transparent wafer to rotate the transparent wafer and detect an orientation flat or a notch based on a change in the position of the roller is also conceivable. There is a problem such as damaging the device. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a transparent wafer alignment apparatus that performs alignment of a transparent wafer by reliably detecting an orientation flat or a notch in a non-contact manner.

[0006]

In order to achieve the above object, the present invention detects an orientation flat or notch formed in a transparent wafer and performs alignment of the transparent wafer based on the position of the orientation flat or notch. In the alignment device, a driving unit for rotating the transparent wafer,
A polarization illuminating unit that irradiates polarized light from a direction in which an incident angle with respect to the surface of the transparent wafer is a polarization angle to a position where the orientation flat or the notch of the transparent wafer that is rotated by the driving unit passes; Receiving means for detecting the polarized light reflected by the transparent wafer, orientation flat detecting means for detecting an orientation flat or notch of the transparent wafer based on the amount of polarized light detected by the light receiving means, and detection of the orientation flat detection means Control means for driving the driving means based on the result and aligning the transparent wafer in a predetermined direction.

According to the present invention, the transparent wafer is rotated by irradiating polarized light from the direction in which the incident angle becomes the polarization angle so that the orifice or the notch of the rotating transparent wafer passes through the transparent wafer surface so as to be totally reflected on the surface of the transparent wafer. Then, the reflected light reflected by the transparent wafer is detected. Then, the orientation flat or the notch is detected based on the detected light quantity of the reflected light, and the alignment of the transparent wafer is performed based on the detection result.

Alternatively, in the alignment apparatus, a driving unit for rotating the transparent wafer, and an incident angle with respect to a surface of the transparent wafer at a position where an orientation flat or a notch of the transparent wafer rotated by the driving unit passes. Polarized light illuminating means for irradiating polarized light from an angle direction, light receiving means for detecting the polarized light radiated by the polarized light illuminating means in a direction transmitting the transparent wafer, and a light amount of the polarized light detected by the light receiving means. An orientation flat detecting unit for detecting an orientation flat or a notch of the transparent wafer; and a control unit for driving the driving unit based on a detection result of the orientation flat detection unit to align the transparent wafer in a predetermined direction. It is characterized by:

According to the present invention, the transparent wafer is rotated by irradiating polarized light from the direction in which the incident angle becomes a polarization angle so that the orifice or the notch of the rotating transparent wafer passes through so that the light is totally reflected on the surface of the transparent wafer. While transmitting, the transmitted light transmitted through the position of the transparent wafer is detected. Then, the orientation flat or the notch is detected based on the detected light quantity of the reflected light, and the alignment of the transparent wafer is performed based on the detection result.

Accordingly, even when a pattern is formed on the surface of the transparent wafer (a surface different from the surface to be irradiated with polarized light), the pattern is not irradiated with polarized light, so that it is affected by the presence or absence of the pattern. The orientation flat or the notch can be easily detected by non-contact without any contact, and alignment of the transparent wafer can be performed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a transparent wafer alignment apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a top view of a prober to which a transparent wafer alignment device according to the present invention is applied. As shown in FIG. 1, the prober is a transparent wafer 10
, A pre-alignment unit 14 for pre-alignment of the transparent wafer 10, and an inspection unit 1 for inspecting a pattern formed on the transparent wafer 10
And 6.

The cassette 12 stores the transparent wafers 10 before and after inspection. The transparent wafer 10 before inspection is pulled out from the cassette 12 to the pre-alignment unit 14 by the arm 18 of the pre-alignment unit 14 described later, and the transparent wafer 10 after inspection is stored in the cassette 12. Pre-alignment unit 1
Reference numeral 4 denotes an arm 18, a turntable 20, a pre-chuck 22, and a sensor 24 for detecting an orientation flat.
Is rotated by the turntable 20. The arm 18 is capable of holding the transparent wafer 10 and moving in the front-back direction, and switches the moving direction between the direction of the cassette 12 and the direction of the inspection unit 16 by the rotation of the turntable 20. Therefore, the arm 18 is connected to the turntable 20.
Of the transparent wafer 10 from the cassette 12, the pre-alignment unit 14 to the cassette 12, and the pre-alignment unit 14 to the inspection unit 1 depending on the rotation angle of
6. It can be transported from the inspection unit 16 to the pre-alignment unit 14.

The pre-chuck 22 attracts the transparent wafer 40 drawn out of the cassette 12 by the arm 18 to rotate the transparent wafer 10 and makes the transparent wafer 10 transparent with reference to the position of the orientation flat detected by an orientation flat detection sensor 24 described later. The wafer 10 is aligned in a predetermined direction (pre-alignment). The orientation flat detection sensor 24 irradiates the edge of the transparent wafer 10 sucked and held by the pre-chuck 22 with a light beam, and detects the light beam reflected by the transparent wafer 10. The orientation flat of the transparent wafer 10 is detected by detecting a change in the amount of light reflected from the transparent wafer 10 while rotating the transparent wafer 10 by the pre-chuck 22. The details of the orientation flat detection sensor 24 will be described later.

The transparent wafer 10 pre-aligned by the pre-chuck 22 and the orientation flat detection sensor 24 is turned 90 ° by the turntable 20 and is transferred by the arm 18 onto the inspection stage 26 of the inspection section 16. Next, the orientation flat detection sensor 24 will be described. 2 and 3 are a side view and a top view, respectively, showing the configuration of the orientation flat detection sensor 24.
As shown in these figures, the orientation flat detection sensor 24
Is the transparent wafer 1 sucked and held by the pre-chuck 22
A light emitting unit 60 for irradiating a light beam from the lower surface direction (a surface on which a pattern is formed is an upper surface and no pattern is formed on a lower surface) at an edge portion of 0, and a light beam reflected by the transparent wafer 10 Light receiving element 70 for receiving light
It is composed of

The light emitting section 60 includes an LED 62 as a light emitting element.
, A collimator lens 64, a slit 66, and a polarizing filter 68. The light output from the LED 62 is collimated by a collimator lens 64, and a part of the collimated light is cut off by a slit 66 to form a narrow rectangular light beam. Then, this light beam passes through the polarization filter 68 and becomes polarized light. The polarized luminous flux generated by the light emitting unit 60 in this manner is applied to the edge portion of the transparent wafer 10 (the position where the orientation flat passes when the transparent wafer 10 rotates) at a polarization angle (Brewster angle). . Here, the polarization filter 68
Since it is installed in a direction that generates linearly polarized light (s-polarized light) having a vibration plane in a plane perpendicular to the incident surface of the transparent wafer 10, the light beam incident on the surface (lower surface) of the transparent wafer 10 Total reflection at the surface. Thereby, ideally, there is no light beam transmitted on the upper surface of the transparent wafer 10, and the light beam is not reflected by the pattern formed on the upper surface of the transparent wafer 10.

The light receiving element 70 receives the light beam emitted from the light emitting section 60 and reflected on the surface of the transparent wafer 10 as described above, and outputs an electric signal corresponding to the received light amount. The electric signal output from the light receiving element 70 is monitored by a control unit (not shown). According to the orientation flat detection sensor 24 configured as described above, when the light emitting unit 60 illuminates the edge portion of the transparent wafer 10 other than the orientation flat 10A with the light beam, the light receiving element 70 causes the entire surface of the transparent wafer 10 to be illuminated. The reflected light beam is received. That is,
In this case, a certain amount of light is received. On the other hand, when the transparent wafer 10 is rotated by the pre-chuck 22 and the orientation flat 10A of the transparent wafer 10 is located at a position where the light beam emitted from the light emitting unit 60 is irradiated, most of the light beam is The light passes upward through the portion of the orientation flat 10A. Thereby, the light amount of the light beam received by the light receiving element 70 at this time decreases. Therefore, the control unit controls the light receiving element 7 of the orientation flat detection sensor 24.
When the signal level output from 0 is lower than a predetermined value, the orientation flat 10A of the transparent wafer 10 is detected.

When the orientation flat 10A is detected in this manner, the transparent wafer 1 at the time when the orientation flat 10A is detected.
The pre-chuck 22 is rotated based on the angle direction of 0 (or the pre-chuck 2 is detected when the orientation flat 10A is detected).
Stop the rotation of 2) and align the transparent wafer 10 in the desired angular direction. In the above embodiment, the transparent wafer 10 is irradiated with polarized light at a polarization angle to the transparent wafer 1.
This polarized light is totally reflected on the surface (lower surface) of the transparent wafer 10.
This is preferable because the amount of reflected light does not depend on the presence or absence of the pattern formed on the substrate. For example, when the transparent wafer 10 is irradiated with non-polarized light, a part of the light passes through the lower surface of the transparent wafer 10. If the transmitted light irradiates the pattern formed on the upper surface, the light is reflected by the pattern and detected by the light receiving element. Therefore, the change in the amount of reflected light detected by the light receiving element is confused with the presence or absence of the pattern with the orientation flat 10A, and it is difficult to detect the change in the amount of reflected light due to the orientation flat.

In the above embodiment, the reflected light amount of the light beam irradiated on the transparent wafer 10 is detected, but the transmitted light amount may be detected. That is, when the transmitted light amount is detected, except for the orientation flat 10A,
The transmitted light of the light beam emitted from the light emitting unit is not detected, and the transmitted light amount of the light beam emitted from the light emitting unit is detected only in the portion of the orientation flat 10A.

Further, in the above embodiment, the case where the orientation flat 10A formed on the transparent wafer 10 is detected has been described. However, even in the case of the notch, it can be detected by the same sensor. In the above embodiment, an example in which the present invention is applied to a prober has been described. However, the present invention can be applied to any apparatus that performs alignment using an orientation flat or a notch on a transparent wafer.

[0020]

As described above, according to the transparent wafer alignment apparatus according to the present invention, the transparent wafer is irradiated with polarized light at a polarization angle and totally reflected on the surface of the transparent wafer. Since the orientation flat or notch of the transparent wafer is detected based on the change in the amount of light, even if a pattern is formed on the surface of the transparent wafer (a surface different from the surface irradiated with polarized light), it is surely not affected by this pattern. Then, the orientation flat or the notch of the transparent wafer can be detected, and the alignment of the transparent wafer can be performed based on this.

[Brief description of the drawings]

FIG. 1 is a top view showing the configuration of a prober to which a transparent wafer alignment apparatus according to the present invention is applied.

FIG. 2 is a side view illustrating a configuration of an orientation flat detection sensor.

FIG. 3 is a top view illustrating a configuration of an orientation flat detection sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Transparent wafer 14 ... Pre-alignment part 16 ... Inspection part 18 ... Arm 20 ... Turntable 22 ... Plane mirror 24 ... Sensor for orientation flat detection 60 ... Light emitting part 62 ... LED 64 ... Collimator lens 66 ... Slit 68 ... Polarizing filter 70 ... Light receiving element

Claims (2)

[Claims] 1. An alignment apparatus for detecting an orientation flat or a notch formed on a transparent wafer and performing alignment of the transparent wafer based on a position of the orientation flat or the notch, wherein: a driving unit for rotating the transparent wafer; A polarization illuminating unit that irradiates polarized light from a direction in which an incident angle becomes a polarization angle with respect to the surface of the transparent wafer at a position where the orientation flat or the notch of the transparent wafer that is rotated by the driving unit passes, and is radiated by the polarization illuminating unit. Light receiving means for detecting the polarized light reflected by the transparent wafer; orientation flat detecting means for detecting an orientation flat or notch of the transparent wafer based on the amount of polarized light detected by the light receiving means; and a detection result of the orientation flat detection means Driving the driving means based on Alignment device of transparent wafers, characterized in that it comprises a control means for aligning the direction. 2. An alignment apparatus for detecting an orientation flat or a notch formed on a transparent wafer and performing alignment of the transparent wafer based on a position of the orientation flat or the notch, wherein a driving unit for rotating the transparent wafer; A polarization illuminating unit that irradiates polarized light from a direction in which an incident angle becomes a polarization angle with respect to the surface of the transparent wafer at a position where the orientation flat or the notch of the transparent wafer that is rotated by the driving unit passes, and is radiated by the polarization illuminating unit. Light receiving means for detecting the polarized light in a direction transmitting the transparent wafer; orientation flat detecting means for detecting an orientation flat or notch of the transparent wafer based on the amount of polarized light detected by the light receiving means; detection of the orientation flat detection means The driving means is driven based on the result, and the transparent wafer is moved to a predetermined direction. Alignment apparatus of the transparent wafer, comprising and a control means for aligning the.