JPH02278809A - Semiconductor wafer - Google Patents

Abstract

PURPOSE:To prevent an effective area of a chip from being reduced by identification marks and to decipher the identification marks after various treatments in a production process have been repeated by a method wherein the identification marks corresponding to items such as a type name, a lot number, a water number and the like of a semiconductor wafer are put on a side face of the semiconductor water. CONSTITUTION:An orientation flat part 2a which has been cut along a chord is formed in one part of a side face 2 of a semiconductor wafer 1. Identification marks 3 corresponding to at least one or more items such as a type name, a lot number, a wafer number and the like are put on the orientation flat part 2a. Thereby, a circuit element and the like are not formed on the side face of the wafer; a process to treat the side face of the wafer is not executed. Accordingly, it is possible to prevent an effective area of a chip from being reduced by the identification marks; it is possible to decipher the identification marks after various treatments in a production process have been repeated.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a technology that is effective when applied to semiconductor wafers, and is applicable to semiconductor wafers that require a product name, lot number, wafer number, etc. It is related to effective technology.

[Prior Art] In process control and failure analysis of semiconductor products, product names, lot numbers, wafer numbers, etc. are required as data for history analysis.

Semiconductor wafers with product names, lot numbers, etc. are described in, for example, Utility Model Publication No. 1982-5633.

In this semiconductor wafer, an identification code corresponding to a product name, lot number, etc. is displayed on the periphery of the front or back surface of the wafer using alphanumeric characters, letters, bar codes, or the like. These identification codes are engraved, printed, or handwritten using ink, laser processing, resist pattern processing, etc., and can be read visually or automatically.

[Problems to be Solved by the Invention] However, the above semiconductor wafer has the following problems.

That is, there is a problem in that the printed identification code disappears due to repeated etching processes in the semiconductor processing process, back grinding processes to maintain a constant thickness, and becomes illegible. In addition, even if this printed, engraved, or handwritten identification code is lucky enough to remain intact, when it is coated with aluminum vapor deposition, the remaining identification code becomes completely invisible and becomes illegible. Therefore, there is a problem that an identification code must be added again.

Furthermore, if this identification code is provided, circuit elements and the like cannot be formed in the area, so there is a problem that the effective surface area of the chip is reduced.

The present invention has been devised in view of the above problems, and it is possible to prevent the effective chip area from being reduced due to identification codes such as product names, lot numbers, wafer numbers, etc.

It is an object of the present invention to provide a semiconductor wafer whose identification code can be read after various treatments in the manufacturing process have been repeated.

[Means for Solving the Problems] Representative inventions disclosed in this application will be summarized as follows.

In other words, the product name and lot number of the semiconductor wafer.

An identification code corresponding to at least one item such as a wafer number is attached to the side surface of the semiconductor wafer.

[Operation] According to the above-described means, an identification code corresponding to at least one item such as the product name, lot number, wafer number, etc. of the semiconductor wafer is attached to the side surface of the semiconductor wafer. Since no circuit elements are formed on the wafer, and there is no process for processing the side surfaces of the wafer, it is possible to prevent the effective area of the chip from being reduced due to the identification code, and to prevent the identification code from being reduced after various processes are repeated in the manufacturing process. The above objective of making it possible to read the text will be achieved.

〔Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a front view of an embodiment of a semiconductor wafer according to the present invention, and FIG. 2 shows a top view of the semiconductor wafer shown in FIG.

In FIGS. 1 and 2, reference numeral 1 indicates a semiconductor wafer, and in this embodiment, a 5-inch wafer (about 42.5 mm in diameter and about 0.55 mm in thickness) is used. This semiconductor wafer 1 has a disk shape, and an orientation flat portion (hereinafter simply referred to as an orientation flat portion) 2a cut out along a chord is formed in a part of a side surface 2 of the semiconductor wafer 1.

Here, in the semiconductor wafer 1 of this embodiment.

An identification code 3 corresponding to the product name, lot number, and wafer number is attached to this orientation flat portion 2a.

This identification code 3 is formed of unevenness, as shown in an enlarged view in FIG.

This identification code 3 encodes the product name, lot number, and wafer number by keeping the cutting depth constant and changing the width of the unevenness.
It is attached in accordance with the S barcode standard and can be automatically read. However, this identification code 3 is JIS
It does not have to be attached according to the bar code standard, but it is sufficient if it is attached with a certain regularity, that is, it is possible to replace it with alphanumeric characters, characters, etc.

Note that the blacked-out portions of the identification code 3 in FIG. 1 are the four portions shaded by the convex portions.

As described above, in this embodiment, since the identification code 3 is attached to the orientation flat portion 2a forming a part of the side surface 2 of the semiconductor wafer 1, no circuit elements or the like are formed on the orientation flat portion 2a. This effect makes it possible to prevent the chip effective area from decreasing due to the identification code 3.

The above-mentioned identification code 3 is attached immediately after purchasing a commercially available crystalline semiconductor wafer 1 by laser processing using a device called a laser marker, grinding processing using a diamond cutter, resist processing using a device called a titler, etc. The depth of this cut is approximately 100 to 200 μm, which can be automatically read (the method will be described later) (it is thought that it is possible to do it at several tens of μm), and the depth of this cut is approximately 100 to 200 μm (the method is described later). The value is within a range that does not cause support when performing the initial direction adjustment (brief alignment) or positioning of the well-known orientation flat portion 2a.

The semiconductor wafer 1 with the identification code 3 attached thereto is first put into processing steps such as diffusion and photoresist which will be performed later.

In this processing step, the initial alignment (pre-alignment) of the orientation flat portion 2a described above is first performed. Since this initial direction alignment is performed by bringing rollers rotating in opposite directions into contact with the orientation flat portion 2a, the cut depth of the identification code 3 is the same as the above-mentioned 100 to Approximately 200 μm is considered appropriate.

After this processing step is completed, the semiconductor wafer 1 is
It is put into an inspection process, an aluminum coating process, and a probe inspection (pass/fail determination) process. In the above processing steps and these steps, the screen 2 of the semiconductor wafer 1 (of course including the orientation flat portion 2a) is not processed at all, so even after the various processing in each of the above processes is repeated, the identification remains. It is possible to read code 3.

Automatic reading of this identification code 3 is very easy as it is a reading of irregularities, and can be easily done using a well-known device that uses a photodetector to read the reflected light from laser scanning, or a device that reads the reflected light all at once using a line sensor. It looks like this.

The automatic reading device is placed in advance at a position opposite to the position of the orientation flat part 2a that is determined by initial orientation alignment etc. (the position of the orientation flat part 2a is determined in any of the above steps). When the semiconductor wafer 1 is sent in, the identification code 3 can be automatically read.

In this way, in this embodiment, the orientation flat portion 2a marked with the identification code 3 can be automatically positioned, and the automatic reading device with a simple configuration can be fixedly arranged. identification code 3 that can be easily read by this automatic reading device.
Since it is now possible to automatically read wafers, it is possible to promote the automation of production lines, and it is also possible to provide automatic reading equipment at low cost. Automation of wafer processing (wafer processing) is also being promoted, and efforts are being made to improve management and failure analysis through wafer-by-wafer tracking.

In the above embodiment, all the identification codes corresponding to the product name, lot number, and wafer number are attached to the side surface of the semiconductor wafer 1, but there is no need to attach unnecessary identification codes; in short, the wafer product name .

At least one or more 2B such as lot number, wafer number, etc.
It is sufficient if an identification code corresponding to the term is attached.

Incidentally, in future process control and defect analysis, it will be necessary to compare data from historical analysis for each wafer, so it is considered necessary to at least attach an identification code corresponding to the wafer number. .

According to the semiconductor wafer configured in this way, the following effects can be obtained.

That is, the product name and lot number of the semiconductor wafer 1.

An identification code corresponding to at least one item such as a wafer number is attached to the orientation flat portion 2 forming the side surface of the semiconductor wafer l.
Since the orientation flat portion 2a forming the side surface of the wafer 1 is not formed with circuit elements, etc.
Since there is no process for machining the orientation flat portion 2a forming the side surface of the chip, it is possible to prevent the chip effective area from decreasing due to the identification code 3, and to make it possible to read the identification code 3 after repeating various processes in the manufacturing process. become.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, in the above embodiment, the identification code 3 is attached to the orientation flat portion 2a that forms a part of the side surface 2 of the semiconductor wafer 1, but the side surface 2 that is not the orientation flat portion 2a is also provided with circuit elements and the like. First, since no processing is performed, it is also possible to attach the identification code 3 to this portion of the side surface 2.

Further, in the above embodiment, the identification code 3 is made of uneven notches, but the identification code may be an alphanumeric character, a bar code, engraved with ink, laser processing, resist pattern processing, etc., or printed or handwritten. It is also possible to read these identification codes visually rather than automatically.

Further, in the above embodiment, an identification code corresponding to the product name, lot number, and wafer number is attached, but it is of course possible to attach the product name, lot number, and wafer number themselves as they are.

It goes without saying that this embodiment can be similarly applied to a square plate-shaped gallium-arsenide wafer used in laser diodes and the like.

[Effects of the Invention] The effects obtained by typical inventions disclosed in Hyohara are briefly explained below.

In other words, the product name and lot number of the semiconductor wafer.

Since an identification code corresponding to at least one item such as a wafer number is attached to the side surface of the semiconductor wafer, circuit elements etc. are not formed on the side surface of the wafer, and the process of processing the side surface of the wafer is simplified. This prevents the effective area of the chip from decreasing due to the identification code, and
This makes it possible to read the identification code after repeating various processes in the manufacturing process.

[Brief explanation of drawings]

FIG. 1 is a front view of an embodiment of a semiconductor wafer according to the present invention, FIG. 2 is a top view of FIG. 1, and FIG. 3 is an enlarged perspective view of an orientation flat portion. 1...Semiconductor wafer, 2...Semiconductor wafer side surface, 3...Identification code.

Claims (1)

[Scope of Claims] 1. A semiconductor wafer, characterized in that an identification code corresponding to at least one item such as the product name, lot number, wafer number, etc. of the semiconductor wafer is attached to the side surface of the semiconductor wafer. 2. The semiconductor wafer according to claim 1, wherein the identification code is attached to an orientation flat portion of the semiconductor wafer. 3. The semiconductor wafer according to claim 1 or 2, wherein the identification code is an automatically readable concavo-convex code.