JP2002280276A - Semiconductor device and its marking method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more quickly conduct close examination on the cause of a defective product by securing the traceability of a semiconductor device, without increasing the cost. SOLUTION: Each semiconductor chip included in a manufactured semiconductor wafer is tested and the information on nondefective chips is encoded. Then the encoded information is marked on the surfaces of the nondefective chips, by using an ink containing a pigment which hardly transmits X rays by means of an ink-jet device, etc. The encoded information marked on the nondefective semiconductor chips includes at least wafer numbers, indicating the number of the semiconductor wafer, chip IDs indicating the positions of the chips in the wafer, and electrical characteristics of the chips.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device in which information on the semiconductor device is coded and marked on a semiconductor device such as a semiconductor wafer or a semiconductor chip, and a marking method therefor.

[0002]

2. Description of the Related Art Conventionally, a semiconductor device used in an expensive device such as a large computer or a supercomputer is given a unique ID (identifier), so that its traceability is ensured, and a defect of a product is ensured. When it occurs, it is used to identify the cause of the defect or to improve the manufacturing problems. On the other hand, an ID is not generally given to a semiconductor device used in an inexpensive device such as a personal computer due to cost and the like.

In a semiconductor device, a probe test is performed on individual semiconductor chips in a state of a manufactured semiconductor wafer, and a defective semiconductor chip is marked with ink, then diced, and is not marked. A good semiconductor chip is assembled. The semiconductor device is stamped with a wafer lot number, and the semiconductor maker can know from which wafer lot the wafer was manufactured based on the wafer lot number.

However, in the method of marking a defective semiconductor chip, there are only two pieces of information of a non-defective product and a defective product. It is not possible to know if it is a characteristic. Therefore, when a defect occurs in the reliability test or the market, the information such as the wafer number, the position in the wafer, and the electrical characteristics of the defective product is not known, so that the defect analysis and the feedback to the manufacturing process can be quickly performed. There was no problem.

On the other hand, after dicing, a method for identifying information such as a wafer number, a position in a wafer, and electrical characteristics of a semiconductor chip for each semiconductor chip is disclosed in, for example, JP-A-7-50233. JP, JP-A-7-307257, JP-A-2000-252176
As disclosed in Japanese Unexamined Patent Publication No.
There have been methods of cutting a fuse with a laser or directly marking the surface of each semiconductor chip.

However, in this method, a space (area) for fuse or laser marking is required, and the chip area is increased, which is disadvantageous in cost.

Similarly, as a method for identifying information such as a wafer number, a position in a wafer, and electrical characteristics of a semiconductor chip for each semiconductor chip after dicing, for example, Japanese Patent Laid-Open No. 7-335510, JP 7
As disclosed in Japanese Unexamined Patent Publication (Kokai) No. 235617/1993, each of a semiconductor wafer, a semiconductor chip and a package
There is also a method in which the semiconductor chip in the package can be verified by giving the D to which semiconductor chip of which semiconductor wafer.

However, in this method, it is necessary to save all the data of the ID of the IC package. In the case of a product to be mass-produced, individual stamping and storage and management of the data increase the cost. The disadvantage was that it was only suitable for expensive products.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art, secure the traceability of a semiconductor device without increasing the cost, and promptly investigate the cause of a product failure. And a marking method therefor.

[0010]

In order to achieve the above object, the present invention provides a probe test for each semiconductor chip included in a manufactured semiconductor wafer to identify good semiconductor chips and defective semiconductor chips. Discriminating, measuring the electrical characteristics of each of the non-defective semiconductor chips, using a marker device such as an inkjet device, using an ink containing a pigment that is difficult to transmit X-rays, the surface of each non-defective semiconductor chip or It is an object of the present invention to provide a marking method for a semiconductor device and a marked semiconductor device, characterized in that information on the semiconductor chip is coded and marked on a back surface.

Here, the information on the semiconductor chip includes at least a wafer number indicating the number of the semiconductor wafer, a chip ID indicating a position of the semiconductor chip in the semiconductor wafer, and an electrical characteristic of the semiconductor chip. It is preferred to include.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a semiconductor device according to the present invention and a marking method thereof will be described in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 is a flow chart of an embodiment showing each step of a marking method for a semiconductor device according to the present invention.
As shown in the flowchart, in the method for marking a semiconductor device according to the present invention, first, each semiconductor chip included in the manufactured semiconductor wafer is subjected to a probe test (S1), and the electrical characteristics of each good semiconductor chip are determined. Is measured (S2), and a good semiconductor chip and a defective semiconductor chip are determined (S3).

Subsequently, an ink jet device (a printing device employing an ink jet printing method) is applied to the surface or the back surface of each non-defective semiconductor chip by using an ink containing a pigment which hardly transmits X-rays. Information about the chip is coded and marked (S4). Thereafter, the semiconductor wafer is diced to separate individual semiconductor chips (S5), and each good semiconductor chip is assembled to obtain an assembled semiconductor device (S6).

The ink is not particularly limited as long as it contains a pigment that does not readily transmit X-rays. Preferred examples include inks containing barium-based and lead-based pigments. The information on the semiconductor chip may include any information, but at least a wafer number indicating the number of the semiconductor wafer, a chip ID (identifier) indicating the position of the semiconductor chip in the semiconductor wafer, and a semiconductor. Preferably, the electrical properties of the chip are included.

In the case where a defective semiconductor chip is marked as in the conventional method of marking a semiconductor device, the semiconductor chip determined to be defective in step S3 cannot be retested. In contrast,
According to the method of the present invention, even if the semiconductor chip is determined to be defective in step S3, the defective semiconductor chip is not marked in step S4. Is also possible (S7).

Hereinafter, the coding of information related to the semiconductor chip will be described.

FIG. 2 is a conceptual diagram of an embodiment of coding of information on a semiconductor chip. FIG. 7A shows an example of a carla code. A square is divided into four areas in a cross-shaped manner, and 16 areas from 0 to 15 are determined depending on whether or not ink is applied to each area. Express the state of the individual.
For example, assuming that the upper right, lower right, lower left, and upper left regions in the figure represent 1, 2, 4, and 8, respectively, the Karla code shown in FIG. , 4,8,
15 is represented.

Also, by using a plurality of Karla codes in combination, for example, 256
Each of the three states can express 4096 states. Therefore, with three or four Karla codes, information on a semiconductor chip, such as the aforementioned wafer number,
It is possible to encode and represent the information of the chip ID. Further, electrical characteristics of the semiconductor chip such as AC (alternating current) characteristics and DC (direct current) characteristics can be encoded and represented.

Although an example of coding information related to a semiconductor chip has been described, the present invention is not limited to this, and information about a semiconductor chip may be coded in any manner.

The semiconductor device manufactured by applying the method of the present invention can be obtained by irradiating the semiconductor device with X-rays and observing the semiconductor device even after assembling the semiconductor chip, so that the coded and marked wafer number, chip ID, Information such as electrical characteristics can be read nondestructively. In addition, there are advantages that the chip area does not increase, that no individual ID is imprinted on the semiconductor device, and that data management of the chip ID is unnecessary, and that information on the semiconductor device is added to the semiconductor device at low cost. be able to.

As described above, the semiconductor device manufactured by applying the method of the present invention has a wafer number,
D. Since various information including electrical characteristics can be added, when a defect occurs in a reliability test or a market, the characteristics of the semiconductor device (what position of which semiconductor wafer, It is possible to immediately know non-destructively the electrical characteristics, etc., and to provide quick feedback to the manufacturing process.

The semiconductor device and the marking method of the present invention are basically as described above. As described above, the semiconductor device of the present invention and the marking method thereof have been described in detail. However, the present invention is not limited to the above embodiments, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.

[0024]

As described in detail above, the semiconductor device and the marking method of the present invention test each semiconductor chip included in the manufactured semiconductor wafer and obtain an ink containing a pigment which is difficult to transmit X-rays. The information on the semiconductor chip is coded and marked on the surface of a non-defective semiconductor chip by an ink-jet apparatus using the method described above. As a result, according to the semiconductor device and the marking method of the present invention, there is no increase in cost due to an increase in chip area, addition of an individual seal to an IC package, maintenance and management of a database, and nondestructive chip traceability of the semiconductor device. And it is possible to provide quick feedback to the semiconductor device manufacturing process.

[Brief description of the drawings]

FIG. 1 is a flowchart of one embodiment showing each step of a marking method for a semiconductor device of the present invention.

FIGS. 2A and 2B are conceptual diagrams of an embodiment of coding of information on a semiconductor chip.

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Claims (2)

[Claims] 1. A semiconductor wafer included in a semiconductor wafer is subjected to a probe test to determine a non-defective semiconductor chip and a defective semiconductor chip. A marking method for a semiconductor device, wherein information on the semiconductor chip is coded and marked on a front surface or a back surface of the non-defective semiconductor chip. 2. A semiconductor device, characterized in that information on the semiconductor chip is coded and marked on an upper surface or a lower surface of the semiconductor chip by using an ink containing a pigment that hardly transmits X-rays.