JPH02218108A - Marking wafer and mark detection - Google Patents

Abstract

PURPOSE:To improve the productivity by displaying required coded information marks on the peripheral face of a wafer. CONSTITUTION:If the peripheral face of a water is made to be a display region for the identification marks of the wafer 10, the whole surface of the wafer 10 can be used as a device pattern forming face. Code information consisting of bars or lines can indicate much information in a small region and can be detected quickly without misreading by reading with an apparatus. Therefore, required coded information marks consisting of bars or lines are displayed on the peripheral surface of the water 10. Thereby wafers and semiconductor devices can be efficiently produced to improve the productivity.

Description

[Detailed Description of the Invention] [Summary] Regarding a marking wafer and a mark detection method for identifying multiple types of wafers, the present invention relates to a marking wafer and a mark detection method for identifying multiple types of wafers. For the purpose of improving efficiency and productivity, coded information marks are displayed on the peripheral edge of the wafer.

Further, the coded required information mark on the marking wafer is detected by at least a light source that irradiates the required information mark, and a photodetector that detects reflected light emitted from the light source and reflected on the peripheral edge surface of the acid wafer. do.

[Industrial application field]

The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a marking wafer and a mark detection method in which identification code information is displayed on the peripheral end surface of the wafer and the code information is detected to improve production efficiency and productivity.

[Conventional technology]

Generally, in semiconductor devices, multiple device patterns formed on a wafer of a predetermined size are individually cut and used as circuit patterns for the semiconductor device, but because there are many types of circuit patterns, multiple types of device patterns are wafers need to be identified by type.

FIG. 3 is a diagram illustrating a conventional wafer identification method.

In the figure, the wafer 2 placed on the X-Y stage 1 so that the device pattern forming surface is exposed is moved by the X-Y stage 2 operated by a signal from a control device (not shown). It is possible to move in the direction.

3 is a signal from a control device (not shown) and is
This is a laser marker that intermittently emits a laser beam L in synchronization with the stage 2, and can freely display a dot pattern such as a single number, a symbol, etc. on the acid wafer according to a command from the control device.

Therefore, normally, a parallel region A close to the oriented flat 2a of the wafer 2 is set as an identification symbol writing region, and a laser beam from the laser marker 3 is intermittently irradiated into the region A, for example, on the wafer 2. Identification symbols such as material loft numbers and wafer numbers are engraved.

In addition, in other methods that do not use such a device, the above-mentioned area A
In some cases, identification symbols similar to those described above may be handwritten using, for example, a diamond marking pen.

Therefore, these recorded material loft numbers, wafer numbers, etc. are visually identified.

However, in such a conventional method, (1) the marking area A occupies a part of the device pattern forming surface of the wafer, resulting in a reduction in the device pattern forming area and a decrease in production efficiency.

(2) Since the engraving area A cannot be wide enough, the recorded contents are limited, and there are more opportunities to refer to and collate other records during the process, which requires extra man-hours.

■It takes time to engrave, and misreading by visual inspection is likely to occur.

■In the case of the marking method using a diamond pen, the yield of device manufacturing decreases due to dust generation.

There are drawbacks such as.

In particular, as manufacturing specifications become more complex due to higher integration of device patterns and larger diameter wafers, solutions to the above-mentioned drawbacks are strongly desired.

[Problem to be solved by the invention]

Conventional wafer identification methods have the problem of not being able to efficiently produce wafers and, by extension, semiconductor devices, making it difficult to expect improvements in productivity.

[Means to solve the problem]

The above-mentioned problem is solved by a marking wafer in which coded required information marks are displayed on the peripheral end surface of the wafer.

Further, the marking wafer is configured to detect the coded required information mark on the marking wafer using at least a light source that irradiates the required information mark and a photodetector that detects reflected light emitted from the light source and reflected on the peripheral edge surface of the wafer. The problem is solved by the mark detection method of

[For production]

If the peripheral end surface of the wafer is used as a display area for the identification symbol of the wafer, the entire surface of the acid wafer can be used as a device pattern forming surface.

On the other hand, code information consisting of lines, dots, etc. can display a lot of information in a small area, and by reading the information with a device, the code information can be detected quickly without misreading.

In the present invention, a coded required information mark made of cotton, dots, etc. is displayed on the peripheral end surface of the wafer, and the coded required information mark is further provided with a light source that illuminates at least the required information mark. A photodetector detects reflected light emitted from the light source and reflected by the peripheral end surface of the acid wafer.

Therefore, it is possible to display a large amount of required information on the wafer/λ without reducing the device pattern formation area on the wafer, and to detect the required information more reliably and easily, making it possible to efficiently produce wafers and, in turn, semiconductor devices. As a result, productivity can be improved.

〔Example〕

FIG. 1 is a diagram illustrating a marking wafer 1 according to the present invention, and FIG. 2 is a diagram illustrating an example of a mark detection method.

In FIG. 1, (1) shows the method of forming the marking wafer 1, and (2) shows the completed wafer A.

In Figures (1) and (2), 10 is, for example, a wafer with a diameter of 6 inches and a thickness of 0.6 to 0.8 mm, and is intermittently rotated by a predetermined angle by a signal from a control unit (not shown). The acid wafer 10 is vacuum chucked onto the upper flat surface 11a of a holder 11 which rotates about an axis S so that the center C of the acid wafer 10 coincides with the rotation axis S. Note that llb in the figure is acid wafer 1.
This is a suction hole for suctioning 0, and its end 11c is connected to a vacuum pump (not shown).

Reference numeral 12 in the figure is a laser marker whose optical axis is directed toward the center C of the wafer 10 on a plane that divides the thickness of the wafer 10 into 1 minute. The holder 1 synchronizes with the intermittent rotation.
1 is stopped, a laser beam L having a diameter of 0.2 to 0.4 mm is emitted.

Here, a method for forming a marking wafer will be explained.

First, hold the wafer 10 so that its center C is at the holder 1 as described above.
The upper flat surface of the holder 11 is aligned with the rotation axis S of the holder 11! While the holder 11 is vacuum chucked on the holder 11, a control section (not shown) is operated to stop the holder 11 at a predetermined position in the rotational direction.

In this case, the predetermined position in the rotation direction can be set with the orientation flat of the wafer 10 as a reference.

For example, in FIG. 2, the angle φ is from the end p0 of the orientation flat 10a of the wafer 10. The position rotated by the rotation direction is defined as the predetermined position in the rotation direction.

Therefore, when the laser beam L is emitted from the laser marker 12, the laser beam L hits 11 points on the wafer 10 by 0.2
The 95 points with approximately the same diameter, that is, 0.2 to 0.4++a+, are marked with the surface roughened by irradiation with a diameter of ~0.41. Thereafter, points pz+pi are similarly marked while rotating the holder 11 by a predetermined angle.

The numbers p1 to p written here are, for example, heading codes common to all wafers.

Therefore, a coded required information mark unique to each wafer is recorded using the above 93 points as a base point.

For example, 24 points located at an angle of φ1 from 95 points are "A",
The ps point at an angle of φ from the 94th point is ``1'', the 95th point at an angle of φ2 from the 92nd point is ``2 II'', the 11 points at an angle of φ3 from the 96th point are 3''r from the Pt point to an angle of φ4 If you set each of the 96 points in ``4'' in advance, A1234 can be obtained using the dot code from p4 to plI above.
” was inscribed.

Note that the four points from p to p+□, located at a position rotated by an angle φ from the 98 point in the figure, represent ending codes corresponding to the above heading code, and are applied to each wafer. This is common.

Therefore, the above heading code and ending
By associating the angle φ between each dot in the area between the codes with numbers or symbols, etc.
0 can be formed.

In Fig. 2 showing the method of detecting the marking wafer, 1
0 is a waeno\ with a dot code engraved on it, and it is fixed at a predetermined position on the holder 11, as in the case of FIG.

Reference numeral 15 in the figure indicates a light source for irradiating the code dots inscribed on the peripheral end surface of the wafer IO, and the light 2 emitted from the light source 15 has a diameter (0, 2 - 0. A beam having a diameter approximately equal to 4 mm) is arranged so as to irradiate a point P on a line dividing the thickness of the peripheral end surface of the wafer by one.

On the other hand, a light intensity detector 16 for detecting reflected light is arranged near the wafer circumferential surface on the reflected optical axis of the light beam l from the irradiation point P on the wafer circumferential end surface, and furthermore, a light intensity detector 16 is arranged to detect the reflected light. For example, a microcomputer 17 equipped with a display section 17a is connected to the device 16.

Here, the wafer is set at the reference position by rotating the holder 11 so that the 98 points in the figure coincide with the above-mentioned point P, and while the light beam i is emitted from the light source 15, the holder 11
is rotated, for example, in the R direction shown in the figure at a constant speed.

In this case, the point P irradiated by the light beam l is the code dot (
P+ -phi), the surface of the code dot portion is roughened, so the light beam l is diffusely reflected and the amount of light incident on the light intensity detector 16 is reduced;
When the point is not on the code dot, the light beam l enters the light intensity detector 16 with almost the same amount of light.

Therefore, since the amount of reflected light incident on the light intensity detector 16 changes in accordance with the dot code, this change in the amount of light is detected by the microcomputer 1 connected to the light intensity detector 16.
7, the code can be converted and the result can be displayed on the display section 17a.

The microcomputer 17 is configured such that the code conversion function starts operating when the heading code shown in Figure (1) is detected, and the code conversion function stops when the ending code shown in Figure (1) is detected. By doing so, when the wafer on the holder 11 is replaced, only the required code information can be converted and displayed.

According to experimental results, it has been confirmed that code information can be reliably read when the rotational angular velocity ω of the holder is about 1 rotation/second and the minimum value of the angle φ between the code dots is about 3 degrees.

〔Effect of the invention〕

As described above, by carrying out the present invention, it is possible to provide a marking wafer and a mark detection method that are efficient and have high productivity without reducing the device pattern forming area.

Although the present invention has been explained in the case of a dot cord, instead of the dot cord, a cord with a width of 0.2~
The same effect can be obtained by marking a bar or the like with a length of 0.3 m+* and a length of about 173 times the wafer thickness.

respectively.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating a marking wafer according to the present invention, FIG. 2 is a diagram illustrating an example of a mark detection method, and FIG. 3 is a diagram illustrating a conventional wafer identification method. In the figure, 10 is the wafer, 10a is oriente → John flat, surface 11 is the holder, lla is the upper flat part, 11b
is the suction hole, llc is the end, 12 is the laser marker, 15 is the light source, 16 is the light intensity detector, 17 is the micro combiator, 17a is the display section, 4 for Kibomei, 4 for Romaro, 8 for explanation, Suzudan mark Diagram showing Yum's threat 9ε

Claims (2)

[Claims] (1) A marking wafer characterized by displaying coded required information marks on the peripheral edge surface of the wafer. (2) Detecting the coded required information mark on the marking wafer using at least a light source that irradiates the required information mark and a photodetector that detects reflected light emitted from the light source and reflected on the peripheral edge surface of the wafer. A marking wafer mark detection method characterized by the following.