JPH10144579A - Producing method of semiconductor device, identification code assignment method which is used in the method, and equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To assign different identification codes to each wafer and further to each pellet parts. SOLUTION: An identification code assignment equipment 10 consists of the following; a liquid crystal mask 13 capable of changing a pattern 25 transmitting a light, a controller 14 which changes and controls the pattern 25 of the mask 13 to a desired pattern, and an irradiating equipment 11 which casts a light on a wafer 1 by penetrating the liquid crystal mask 13. After the liquid crystal mask 13 is made to optically face pellet parts 4 of a wafer 1, a light is casted penetrating the liquid crystal mask 13, and identification codes 5 are assigned. After that, the identification codes 5 are read with an identification code reader, and processing data and inspection data are stored in a storage device, corresponding to the identification codes 5. The stored data can be retrieved with the identification codes 5 when failure analysis or the like is necessary. Thereby desired identification codes can be assigned to each pellet part of a wafer by changing the pattern of the liquid crystal mask, so that failure analysis precision or the like can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device production technique, and more particularly, to a semiconductor device manufacturing process, which is effective when used in a so-called pre-process for manufacturing a semiconductor device on a semiconductor wafer (hereinafter, referred to as a wafer). About things.

[0002]

2. Description of the Related Art In a so-called pre-process in a manufacturing process of a semiconductor device, a lot code and a wafer code are attached in advance as identification codes for identifying individual wafers for each wafer, and each lot code and wafer code are assigned to each lot code and wafer code. Adopting a semiconductor device production method that improves production management, product characteristic analysis, failure analysis, foreign matter analysis, yield, etc. by managing wafer production management data and data such as measured values related to electrical characteristics in response Have been.

In a conventional method of manufacturing a semiconductor device of this type, a lot code and a wafer code, which are identification codes of a wafer, are transferred to each wafer simultaneously with the transfer of the semiconductor device by using a photomask for transferring the semiconductor device to the wafer. Is attached.

[0004] Japanese Patent Application Laid-Open No. 6-29167 discloses an example of a technique for attaching an identification code to a wafer.

[0005]

However, in the conventional method of manufacturing a semiconductor device, a photomask corresponding to the number of wafers is required to attach different wafer codes to each wafer, so that the production cost is greatly increased. There is a problem. Also, there is a problem that it is practically difficult to attach a pellet identification code (hereinafter referred to as a pellet code) for identifying different pellet portions in one wafer for the same reason.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an identification code attaching technique capable of attaching a different identification code to each wafer or even within a wafer.

Another object of the present invention is to provide a semiconductor device production technique using the identification coding technique.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0009]

The outline of a typical invention among the inventions disclosed in the present application is as follows.

That is, after a liquid crystal mask capable of controlling a pattern for transmitting light is optically opposed to a portion to be identified on the surface of the semiconductor wafer, light is transmitted through the liquid crystal mask to the portion to be identified. And is provided with an identification code.

According to the above-described means, a desired identification code can be attached to each of the identification code attaching portions of the semiconductor wafer by changing the pattern of the liquid crystal mask. Therefore, it is possible to manage data such as production management data for each semiconductor wafer and data such as measured values relating to electrical characteristics in accordance with each identification code, so that production management, product characteristic analysis, failure analysis, foreign substance analysis, yield, etc. Can be greatly improved.

[0012]

FIG. 1 is a perspective view showing an identification code attaching apparatus according to an embodiment of the present invention. FIGS. 2A and 2B are enlarged partial sectional views showing an identification code attaching method. FIGS. 3A and 3B are plan views of a wafer, and FIG. 3B is a plan view of an identification code pattern. FIG. 4 is a schematic view showing a method for producing a semiconductor device according to one embodiment of the present invention, and FIG. 5 is a process chart showing a method for producing a semiconductor device according to one embodiment of the present invention. FIG. 6 is a schematic diagram showing an identification code reading device used in the method of manufacturing a semiconductor device according to one embodiment of the present invention. FIG. 7 is a perspective view showing a foreign matter inspection apparatus as one embodiment of the processing apparatus.

In the method of manufacturing a semiconductor device according to the present embodiment, as shown in FIG. 3A, a first main surface 2 of a wafer 1 as a work is regularly arranged corresponding to an orientation flat 3. Each of the pellet parts 4 formed in the above is provided with an identification code 5 encoded by a combination of English characters and numerals. The identification code 5 includes a lot identification code (hereinafter, referred to as a lot code) 6 indicating the lot number of the wafer 1, a wafer identification code (hereinafter, referred to as a wafer code) 7 indicating each wafer number in the lot. A pellet identification code (hereinafter, referred to as a pellet code) 8 indicating the number of each pellet portion in the wafer. The identification code 5 is formed by drawing an alphanumeric character and a number having an uneven structure using an identification code attaching device described later, and can be optically read by an identification code reading device described later. I have.

Here, in the so-called pre-process in the manufacturing process of the semiconductor device, each of the pellet portions 4 is manufactured by dividing a plurality of semiconductor devices as products into the first main surface 2 of the wafer 1 regularly and horizontally. In the wafer 1 as a work, each product part of the work is substantially formed. Therefore, the pellet code 8 can serve as a product identification code.

The identification code attaching device 1 shown in FIG.
Reference numeral 0 denotes an irradiation device 11 for irradiating a light beam capable of exposing the photoresist, and an irradiation direction of the irradiation device 11 is an optical system 12 including a mirror and various lenses.
The liquid crystal mask 13 is arranged via the. The liquid crystal mask 13 is configured using a liquid crystal panel, and is configured to be able to electrically control and change the pattern through which light is transmitted. The liquid crystal mask 13 has a controller 14
Are electrically connected, and the controller 14 is configured to change a pattern through which light is transmitted by controlling a voltage applied to the liquid crystal.

A half mirror 15 is disposed on the optically opposite side of the liquid crystal mask 13 from the irradiation device 11. A screen 16 is arranged on the reflection side of the half mirror 15, and the screen 16 is configured so that the pattern of the liquid crystal mask 13 can be observed. A reduction lens 18 is disposed on the transmission side of the half mirror 15 via a mirror 17. The reduction lens 18 is configured to reduce the pattern of the liquid crystal mask 13 and project the pattern on the surface of the wafer 1. Although not shown, the identification code attaching device 10 is configured so that the projection position of the reduction lens 18 on the wafer 1 can be sequentially changed.

The identification code attaching device 10 according to the above configuration
An identification code attaching method according to an embodiment of the present invention will be described with reference to FIGS. 1, 2 and 3. FIG.

The identification code attaching device 1 shown in FIG.
FIG. 2 shows the wafer 1 to which the identification code 5 is assigned by “0”.
As shown in (a), a photoresist 22 is applied on the wiring metal film 21. A wiring pattern exposure portion 23 exposed in the wiring pattern exposure step is formed on the photoresist 22, and a metal wiring 24 is formed based on the wiring pattern exposure portion 23 as described later.

As shown in FIG. 1, when a predetermined pellet portion 4 of the wafer 1 is opposed to the projection position of the reduction lens 18, light from the irradiation device 11 is transmitted through the liquid crystal mask 13 and By being irradiated as shown in (b), the identification code pattern 25 formed on the liquid crystal mask 13 is transferred to the photoresist 22. The identification code pattern 25 includes a transmission part 25a for transmitting light and a light shielding part 25b for shielding light. The light transmitted through the transmission part 25a forms an identification code pattern photosensitive part 29 in the photoresist 22. For the sake of convenience, in FIG. 2B, the identification code pattern 25 of the liquid crystal mask 13 is shown at the same magnification as the identification code pattern photosensitive portion 29. It is larger than the photosensitive section 29.

Before the light is irradiated, an identification code pattern 25 corresponding to the identification code 5 to be attached to the pellet portion 4 to be irradiated with the light is applied to the liquid crystal mask 13 by the controller 14, for example, as shown in FIG. It is formed as shown in FIG. The identification code pattern 25 shown in FIG. 3B corresponds to the lot code pattern 26, the wafer code pattern 27, and the pellet code pattern 2 corresponding to the identification code 5 shown in FIG.
8 is provided. For example, the pellet code pattern 28 of the identification code pattern 25 is sequentially changed for each pellet part 4 under the control of the controller 14.

After the identification code pattern photosensitive portion 29 with the identification code pattern 25 is formed on all necessary pellet portions 4, the wafer 1 is subjected to a developing process and an etching process. After the development process and the etching process, the metal wiring 24 and the identification code 5 are formed on the wafer 1 by the wiring metal film 21 as shown in FIG.

Next, a method of manufacturing a semiconductor device according to an embodiment of the present invention using a wafer to which an identification code is attached by the above-described identification code attaching method will be described.

In this embodiment, the identification code reader shown in FIG. 6 is used. An identification code reader is provided for each processing device. FIG. 7 shows a foreign matter inspection device as an example of a processing device provided with an identification code reading device. Here, the identification code reading device shown in FIG. 6 and the foreign matter inspection device shown in FIG. 7 will be described.

The foreign substance inspection device 51 includes a machine frame 52 and a controller 56. On the machine frame 52, a loading station 53 and an unloading station 54, a robot (not shown) as a transfer device,
An identification code reader 30 is provided.
The loading station 53 is disposed at a position on one side of a central portion on the machine frame 52. The unloading station 54 is arranged on one side of the machine frame 52 side by side with the loading station 53. The wafer 1 provided with the identification code is supplied to the foreign matter inspection device 51 in a state of being stored in the cassette 57. Incidentally, each cassette 57 has a large number of holding grooves (slots) arranged in many stages (usually 25 stages), and wafers 1 are stored in the holding grooves.
Are inserted, a plurality of (typically, one lot) wafers 1 are stored in a regularly aligned state.

The robot operates the arm controlled by the controller 56 to take out one wafer 1 from the actual cassette 57 in the loading station 53 by a grip and transport it to the identification code reading device 30. It is configured to be transported from the reading device 30 to the processing chamber 55 of the foreign matter inspection device 51 and the unloading station 54.

The identification code reading device 30 is disposed at a substantially central position in a rear portion on the machine frame 52. The identification code reader 30 is provided with a recognition stage 31. Above the recognition stage 31, a lens barrel 32 and a television camera 35 as an image capturing device are supported by a stand (not shown). A light source 34 is provided in the lens barrel 32.
Are optically connected via an optical fiber 33, and light from a light source 34 is adjusted by a lens barrel 32 through the optical fiber 33 toward the recognition stage 31 so as to be irradiated. The television camera 35 is configured to sequentially capture each identification code 5 of the illuminated wafer 1 on the recognition stage 31.

An identification code recognition device 36 is electrically connected to the television camera 35 via a cable 36a. The identification code recognition device 36 is composed of an image processing device or the like, and is capable of recognizing the identification code 5 attached to the wafer 1 based on an imaging signal from the television camera 35. A monitor 37 is connected to the identification code recognizing device 36 so that the monitor 37 monitors the shooting situation of the television camera 35. A data processing device 40 constructed from a computer or the like is connected to the identification code recognizing device 36 by communication engineering, and the data processing device 40 executes data processing described later.

A memory 41 is connected to the data processing device 40 by communication engineering. The memory 41 stores data relating to processing conditions for the wafer and data of processing results.
History data corresponding to the pellet code 8 is stored based on various processing condition data and various processing result data for each processing apparatus that performs a predetermined processing on the wafer 1. A file is created. An example of the history data file stored in the memory 41 for the foreign substance inspection device 51 is as shown in Table 1 below. Here, Table 1 shows the pellet code 8, processing (inspection) condition data and processing (inspection).
And the result data.

[0029]

As described above, a plurality of wafers 1 to which the identification code 5 has been attached are stored in the cassette 57.
It is supplied to the loading station 53 of the foreign substance inspection device 51. One wafer 1 supplied to the loading station 53 is paid out from the cassette 57 and set on the recognition stage 31 of the identification code reader 30. The identification code 5 of the wafer 1 set on the recognition stage 31 is read by the identification code reading device 30. Here, the identification code reading operation of the identification code reading device 30 will be described.

In the recognition stage 31, the wafer 1 is supported horizontally, as shown in FIG.
It faces the lens barrel 32 and the television camera 35 of the identification code reader 30. When the wafer 1 is directly opposed to the television camera 35, the identification code recognition device 36 performs the operation of reading the identification code 5. The read identification code 5
Is transmitted to the data processing device 40 connected to the identification code recognition device 36, and the processing condition code is collated for each pellet code 8.

After the identification code 5 is read, the wafer 1 as a work is transferred to a processing chamber 55 by a robot and set on an XY table (not shown) as an inspection stage. Subsequently, the foreign substance inspection device 51 performs the foreign substance inspection processing according to the set processing conditions. The inspection result of the foreign substance inspection device 51 is transmitted to the memory 41, stored corresponding to the pellet code 8 in each identification code 5, and the history data file shown in Table 1 is created.

When a predetermined foreign substance inspection is completed for the wafer 1 carried into the processing chamber 55 of the foreign substance inspection apparatus 51, the wafer 1 is carried out of the processing chamber 55 and stored in the empty cassette 57 of the unloading station 54. The next wafer 1 whose identification code 5 has been read by the identification code reading device 30 is carried into the processing chamber 55 of the foreign matter inspection device 51. Incidentally, the identification code reading operation for the next wafer 1 can be simultaneously performed during the foreign substance inspection operation for the previous wafer 1.

By repeating the above operations, the foreign substance inspection apparatus 51 sequentially performs the foreign substance inspection, which is an example of the semiconductor device production processing, on each wafer 1 as a work.

For the sake of convenience, the description is omitted, but in the same manner as in the above-described operation of the foreign matter inspection device 51, the history data shown in Table 1 above is collated with the same pellet code in the processing device of each process. Files are created sequentially.

The history data file created as described above is used for analyzing the characteristics of the pellet portion 4 of the wafer 1,
It is used as appropriate for failure analysis and foreign matter analysis. In this case, since the history data is organized in the history data file for each of the pellets 4 of each of the wafers 1, the analysis of each of the pellets 4 becomes possible, and the accuracy of the analysis is extremely enhanced. .

Further, the data processing unit 40, based on the data transmitted from each identification code reading device when each wafer 1 passes through each process, processes the progress of the process, the date and time of completion of the process, and the data file relating to the change of the production plan. (Not shown). In this case, since the data is organized in each pellet section 4 of each wafer 1 in this data file, production control of each pellet section 4 of the wafer 1 becomes possible, and the precision of the management is extremely enhanced. Become.

Thereafter, in a so-called post-process in the production process of the semiconductor device, the wafer 1 is diced for each of the pellet portions 4 and then assembled and packaged for each of the pellets, and an electrical characteristic test is performed. Will be shipped to the market.

If a failure is found in the pellet after packaging, the identification code 5 attached to the failed pellet is read by the identification code reader, and the cause of the failure of the pellet is analyzed. . In this case, since the history data is stored in the history data file of the memory 41 for each wafer 1 and for each pellet portion 4, it is possible to perform failure analysis for each pellet, and the accuracy of failure cause analysis is high. It will be greatly enhanced.

According to the above embodiment, the following effects can be obtained. By using a liquid crystal mask capable of controlling a pattern for transmitting light, the identification code is attached to the wafer, so that the contents of the identification code can be sequentially changed by changing the pattern of the liquid crystal mask. Therefore, a different pellet code can be assigned to each pellet portion.

As described above, a history data file such as wafer production management data, processing condition data, and inspection result data can be created corresponding to each pellet code in the same wafer. The accuracy of production management, characteristic analysis, failure analysis, and foreign substance analysis can be greatly improved, and the yield and production efficiency of the semiconductor device production method can be greatly improved.

If a failure is found in the pellet after packaging, by reading the identification code attached to the failed pellet, it is possible to analyze the cause of the failure of the pellet and the like. Since history data is organized in the history data file for each wafer and for each pellet, failure analysis can be performed for each pellet, and high analysis accuracy can be achieved.

Although the invention made by the inventor has been specifically described based on the embodiment, the invention is not limited to the embodiment, and various modifications can be made without departing from the gist of the invention. Needless to say.

For example, the identification code is not limited to the configuration using alphabetic characters or numbers, but may be configured using a barcode, a pericode, or the like.

In the above description, the case where the invention made by the present inventor is mainly applied to the foreign matter inspection technology which is the background of the application has been described. However, the present invention is not limited to this. Can be applied generally.

[0046]

The effects obtained by typical aspects of the invention disclosed in the present application will be briefly described as follows.

The identification code is attached to the wafer by using a liquid crystal mask capable of controlling a pattern through which light is transmitted. By changing the pattern of the liquid crystal mask, the contents of the identification code are sequentially changed. Since it is possible to go, a different pellet code can be assigned to each pellet portion.

Since a data file such as wafer production management data, processing condition data, and inspection result data can be created corresponding to each pellet code in the same wafer, production management and characteristics in a semiconductor device production method can be achieved. The accuracy of analysis, failure analysis, and foreign matter analysis can be greatly improved, and the yield, production efficiency, and the like of a semiconductor device production method can be greatly improved.

If a failure is found in the pellet after packaging, by reading the identification code attached to the failed pellet, it is possible to analyze the cause of the failure of the pellet, etc. Since the history data is arranged in the data file for each wafer and for each pellet portion, failure analysis for each pellet can be performed, and high analysis accuracy can be achieved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an identification code attaching device according to an embodiment of the present invention.

FIGS. 2A and 2B show an identification code attaching method, wherein FIG. 2A is an enlarged sectional view before an identification code is attached, FIG. It is an expanded sectional view after a code is attached.

FIG. 3 also shows an identification code attaching method,
(A) is a plan view showing a wafer, and (b) is a plan view of an identification code pattern.

FIG. 4 is a schematic view illustrating a method for producing a semiconductor device according to an embodiment of the present invention.

FIG. 5 is a process drawing similarly.

FIG. 6 is a schematic diagram showing a code reader used in a method of manufacturing a semiconductor device according to an embodiment of the present invention.

FIG. 7 is a perspective view showing a foreign matter inspection apparatus as one embodiment of the processing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wafer, 2 ... 1st main surface, 3 ... Orientation flat, 4 ... Pellet part, 5 ... Identification code, 6 ... Lot identification code (lot code) which displays a lot number, 7
... Wafer identification code (wafer code) for displaying wafer number, 8 ... Pellet identification code (pellet code) for displaying pellet number, 10 ... Identification code attaching device, 11
... irradiation device, 12 ... optical system, 13 ... liquid crystal mask, 14 ...
Controller, 15: half mirror, 16: screen, 17: mirror, 18: reduction lens, 21: wiring metal film, 22: photoresist, 23: wiring pattern photosensitive part,
24 ... metal wiring, 25 ... identification code pattern, 25a ...
Transmissive part, 25b ... light shielding part, 26 ... lot code pattern, 27 ... wafer code pattern, 28 ... pellet code pattern, 29 ... identification code pattern photosensitive part, 30 ...
Identification code reader, 31: recognition stage, 32: lens barrel, 33: optical fiber, 34: light source, 35: television camera, 36: identification code recognition device, 36a: cable, 3
7 monitor, 40 data processing device, 41 memory
51: foreign matter inspection device, 52: machine frame, 53: loading station, 54: unloading station,
55: processing chamber, 56: controller, 57: cassette.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kaoru Takehisa 3-1-1, Sachimachi, Hitachi-City, Ibaraki Prefecture Inside the Hitachi Works, Hitachi, Ltd. (72) Inventor Hiroshi Sadohara 5-Chome, Josuihoncho, Kodaira-shi, Tokyo No. 20 No. 1 Semiconductor Division, Hitachi, Ltd.

Claims (9)

[Claims] An identification code for identifying a semiconductor wafer is provided on a surface of a semiconductor wafer on which a semiconductor device is formed,
A method for producing a semiconductor device, comprising: an identification code attaching step provided by a liquid crystal mask capable of controlling a light transmitting pattern; and an identification code reading step for reading the identification code. 2. The semiconductor device according to claim 1, wherein the identification code includes a pellet identification code formed on a pellet portion corresponding to each semiconductor device to be formed on the semiconductor wafer. The production method of the semiconductor device according to the above. 3. The method according to claim 1, wherein a history of the semiconductor wafer to which the identification code is attached is stored in correspondence with the identification code. 4. The pellet identification code is read after the semiconductor wafer is divided into each pellet portion,
4. The method according to claim 3, wherein the history corresponding to the pellet identification code is searched. 5. The semiconductor device according to claim 1, wherein the identification code is printed on the surface of the semiconductor wafer by the liquid crystal mask, applied by a lithography process, and read by optical means. 5. The method for producing a semiconductor device according to 1, 2, 3, or 4. 6. An identification code attaching method used in the method of manufacturing a semiconductor device according to claim 1, wherein the liquid crystal mask is optically opposed to the identification attached portion on the surface of the semiconductor wafer. Thereafter, light is transmitted through the liquid crystal mask and illuminated to the identification code attaching portion, and an identification code is attached thereto. 7. The identification code attaching method according to claim 6, wherein a pattern of the liquid crystal mask is changed to a desired pattern for each of the identification code attaching portions. 8. An identification code attaching device used in the method of manufacturing a semiconductor device according to claim 1, wherein the liquid crystal mask is optically opposed to an identification target attaching portion on a surface of the semiconductor wafer. An identification code attaching apparatus, characterized in that light is transmitted through the liquid crystal mask and illuminated on the identified code attaching section, so that an identification code is attached. 9. A liquid crystal mask capable of changing a pattern for transmitting light, a controller for changing and controlling a pattern of the liquid crystal mask to a desired pattern, and an irradiation for transmitting light to the semiconductor wafer through the liquid crystal mask. 9. The identification code attaching device according to claim 8, comprising a device.