JPS6157701B2 - - Google Patents

Description

Detailed Description of the Invention The present invention allows light to be incident on the reference cut surface of a single crystal wafer, and the reflected light is used to align the crystal orientation of the single crystal wafer with the direction of scribing, thereby easily and accurately scribing the wafer. This invention relates to a single-crystal wafer scribing device that enables wafer scribing.

Generally, a wafer scribing device is a device that divides a wafer into a large number of chips (pellets), and is used when dividing a single crystal wafer such as a semiconductor crystal or a piezoelectric dielectric crystal used as a material for a surface acoustic wave filter substrate into chips. First, the crystal orientation of the single-crystal wafer is determined by cleavage or X-ray diffraction, etc., and a reference plane is obtained by cutting it with a cutter. A scribe cut is visually measured at the intersection of this reference plane and the surface of the single-crystal wafer. according to the cutting direction of the tar,
I'm scribing. Therefore, it is difficult to accurately determine the direction of scribing, and when scribing a single crystal wafer with cleavability,
There is an inconvenience that the scribe is deviated from the cleavage direction. Furthermore, in order to improve accuracy, it is necessary to cut off the reference surface considerably, which wastes the sample and is uneconomical.

This invention takes into account the above-mentioned conventional problems and makes it possible to easily and accurately match the crystal orientation of a single crystal wafer with the scribing direction. Next, one embodiment of this invention will be described. This will be explained in detail with reference to the accompanying drawings.

In the figure, 1 is an apparatus main body, and 2 is a wafer holding stand rotatably mounted on the apparatus main body 1, and a large number of fine holes are provided in the upper surface of the central part for holding the wafer. 3 is a single crystal wafer held on the wafer holder 2; for example, a semiconductor single crystal wafer such as Ge or Si, or a piezoelectric dielectric single crystal wafer such as LiNbO ₃ as a substrate material of a surface acoustic wave filter. be. 4 is a reference cut surface obtained by cutting the single crystal wafer 3 by cleaving or the like; 5 is a scribe cutter installed vertically above the single crystal wafer 3; and 6 is a halogen for making light incident on the reference cut surface 4. A light source consisting of a lamp or an Ar laser light source; 7 is a slit that restricts and passes the light from the light source 6; 8 is an incident hole 9 for the light from the slit 7;
This cover is provided near the wafer holding table 2 and facing the center of rotation of the holding table 2, and is made of, for example, semi-cylindrical aluminum whose inner surface is painted black to prevent scattered light. 10 is a half mirror that reflects the light from the incident hole 9 and directs it parallel to the upper surface of the wafer holder 2 toward the center of rotation of the holder 2 so as to be incident on the reference cut surface 4 of the single-crystal wafer 3;
Reference numerals 11 and 12 are two photodetectors placed opposite each other at a predetermined interval on both sides of the reflected light from the half mirror 10 near the opening of the cover 8 on the side of the holding table 2;
For example, a phototransistor. Reference numeral 13 denotes a slit provided on the opposite side of the half mirror from the holding base 2 to limit and pass reflected light from the reference cut surface 4;
Reference numeral 4 denotes a phototransistor, a photomultiplier tube, etc., which is provided on the opposite side of the slit 13 from the half mirror 10 and located between the two photodetectors 11 and 12, that is, on the extension of the optical path of the reflected light from the half mirror 10. High-sensitivity photodetector, 15 is a display meter connected to high-sensitivity photodetector 14, 16 is both photodetector 1
17 is a motor such as a pulse motor that rotates the wafer holding table 2; and 18 is a rotating operation section for the wafer holding table 2, which is made of, for example, a screw.
The direction of scribing by the scribe cutter 5 is perpendicular to the direction of incidence of the reflected light from the half mirror 10.

Next, the operation of the embodiment will be explained.
First, a single crystal wafer 3 is placed on the wafer holder 2, and by driving an exhaust device (not shown) provided at the bottom of the wafer holder 2, a large number of fine particles on the wafer holder 2 are removed. The single crystal wafer 3 is sucked into a predetermined position on the wafer holding table 2 through the hole, and is held by the scribe cutter 5 so that it can be scribed.

Then, the light emitted from the light source 6 passes through the slit 7 and the entrance hole 9 of the cover 8 to the half mirror 10.
The light reflected by the half mirror 10 is incident on the reference cut surface 4 of the single crystal wafer 3. Here, when the single crystal wafer 3 is placed on the wafer holding table 2 mentioned above, it is set by visual measurement so that the reference cut surface 4 is almost parallel to the direction in which the scribe cutter 5 scribes, but the broken line As shown in FIG. The light is reflected by the reference cut surface 4, and this reflected light is irradiated onto a photodetector 11 or 12 and detected. Then, a detection signal is output from the photodetector 11 or 12 that receives the light, and the control circuit 16 is operated, the motor 17 is driven, and the wafer holding table 2 is rotated. This rotation of the motor 17 in the forward or reverse direction is caused by the rotation of the motor 17
This continues until there is no more detection signal from the reference cut surface 4, and the reflected light from the reference cut surface 4 is guided between the two photodetectors 11 and 12.

Further, in order to accurately align the crystal orientation of the single crystal wafer 3 with the direction of the scribe, the wafer holding table 2 is rotated by the rotation operation unit 18, and the reflected light passing between both the photodetectors 11 and 12 is reflected from the half mirror. Adjustment is made so that the light passes through 10 and enters the high-sensitivity photodetector 14 through the slit 13, and fine adjustment is made using the meter 15 so that the amount of light incident on the high-sensitivity photodetector 14 is maximized. Therefore, the reference cut plane 4 of the single crystal wafer 3 and the direction of scribing by the scribe cutter 5 exactly match.

As described above, the present invention includes a rotatable wafer holder that holds a single crystal wafer, and a reference cut plane of the single crystal wafer held on the wafer holder that is parallel to the upper surface of the wafer holder. a light source that inputs light directed toward the rotation center of the wafer holding table; and two light detection paths that are arranged on both sides of the light input path and receive reflected light from the reference cut surface of the single crystal wafer; a motor controlled by the photodetector that receives the light to rotate the wafer holder and guide the reflected light between the photodetectors; and a high-sensitivity photodetector provided between the photodetectors. A single crystal wafer scribing apparatus is characterized in that the single crystal wafer scribing apparatus further comprises: a rotating operation section for the wafer holder that guides the reflected light to the center of the high-sensitivity photodetector.

Therefore, according to the present invention, the reflected light of the light incident on the reference cut surface of the single crystal wafer from the light source is controlled by the two photodetectors to control the rotation of the wafer holder, and the rotation operation section to control the wafer holder. By finely adjusting the rotation of the wafer, the single crystal wafer can be accurately positioned by guiding it to the center of the highly sensitive photodetector, and regardless of the size of the single crystal wafer, the single crystal wafer Even if the position is slightly shifted from the center of rotation on the holding table, accurate positioning can always be achieved, and it can be easily and accurately positioned without using complicated means such as X-ray diffraction as in the past. The crystal orientation of a single crystal wafer can be aligned with the scribing direction.

[Brief explanation of the drawing]

The drawing is a configuration diagram of one embodiment of the single crystal wafer scribing apparatus of the present invention. 2... Wafer holding stand, 3... Single crystal wafer, 4
...Reference cutting surface, 5...Scribe cutter, 6...
Light source, 11, 12...photodetector, 14...high sensitivity photodetector, 17...motor, 18...rotation operation unit.

Claims (1)

[Claims] 1. A rotatable wafer holder that holds a single crystal wafer, and a reference cut plane of the single crystal wafer held on the wafer holder, parallel to the top surface of the wafer holder and at the center of rotation of the wafer holder. Controlled by a light source that inputs directed light, two photodetectors that are placed on both sides of the light incident path and that receive reflected light from the reference cut surface of the single crystal wafer, and the photodetector that receives the light. a motor that rotates the wafer holding table and guides the reflected light between the two photodetectors; a high-sensitivity photodetector provided between the two photodetectors; A single-crystal wafer scribing apparatus comprising: a rotating operation section for guiding the wafer holder to the center of a photodetector.