JP2964522B2 - Semiconductor wafer, method of manufacturing the same, and method of selecting semiconductor chips - Google Patents

Description

The present invention relates to a semiconductor wafer and a method for manufacturing the same.

[Conventional technology]

2. Description of the Related Art Conventionally, in a semiconductor device manufacturing process, the same type or a plurality of types of semiconductor chips are simultaneously manufactured on the same semiconductor wafer. A plurality of semiconductor chips manufactured on the same semiconductor wafer are tested in a wafer state, and as a result of pass / fail judgment, a mark such as a mechanical scratch or ink is attached to a defective product, and in a subsequent process, Good products were extracted and used with reference to this mark.

[Problems to be Solved by the Invention] Semiconductor chips of the same type are manufactured without particular distinction on the above-mentioned conventional semiconductor wafer, and chips determined to be non-defective are collectively used as non-defectives without discrimination. It had been. However, if you want to use the chip in a high frequency band such as microwaves, or if you want to use the chip more effectively by distinguishing the chip application based on the value of the mutual conductance or the drain / source saturation current in the chip, By managing and using the withstand voltage value of, the inspection results for individual semiconductor chips, especially when using those with high withstand voltage under more severe use conditions,
Even if it is necessary to record the history of handling clearly, or if it is necessary to judge various characteristics comprehensively and use them in order from the better one, chips are distinguished individually in the conventional semiconductor wafer. This has not been practically possible. In the test of GaAs semiconductor wafers with excellent high-frequency characteristics, if a method of scratching defective products with a mechanical scratch (scratch marker) is performed, the scratch may be generated when the test is divided into individual chips (scribed). As a result, the non-defective chips also have the disadvantage that the chips are broken and broken. In addition, the method of scratching with a laser (laser marker) is based on the problem that arsenic in a GaAs substrate is harmful to the human body, and gold, which is generally used as a wiring material on a GaAs semiconductor wafer, is formed into a ball shape. There was a problem of flying and smearing other chips or the needle used for the test.

An object of the present invention is to provide a semiconductor wafer and a method for manufacturing the same, which can easily distinguish individual semiconductor chips formed in the same wafer.

[Means for solving the problem]

The semiconductor wafer of the present invention is a semiconductor wafer in which a plurality of types of semiconductor chips are formed on the same substrate, and a plurality of types of semiconductor chips each having a first mark which can be individually recognized. And a second mark is provided on each of the semiconductor chips so that a plurality of types of semiconductor chips can be recognized for each type.

Alternatively, in order to manufacture the semiconductor wafer, an identification mark is provided on a mask that exposes the entire wafer at a time among masks used in a wafer manufacturing process.

Alternatively, a desired chip is selected using the relationship between the inspection data and the identification mark.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a plan view of a semiconductor wafer for explaining one embodiment of the present invention. As shown in FIG. 1, a semiconductor chip 2 is formed on a semiconductor wafer 1. In this embodiment, each semiconductor chip 2 is provided with a semiconductor chip identification pattern 30 for distinguishing the type of semiconductor chip and a mark of a reference number pattern 20 for distinguishing each chip.

The formation of the semiconductor chip identification pattern 30 and the reference number pattern 20 can be easily transferred onto the semiconductor wafer by forming the reference number pattern and the like on a mask that exposes the semiconductor wafer at one time. .
It is also possible to use a mask dedicated to the formation of the verification number pattern 20. Furthermore, if masks with different reference numbers for the same number of semiconductor wafers manufactured in the same lot are prepared, it becomes possible to manage not only the same wafer but also all semiconductor chips in the same lot individually.

FIG. 2 is a partially enlarged view of FIG. As shown in the figure, a reference number pattern 20 is formed on a protection film or a passivation film provided on each semiconductor chip 2.

With such a configuration, it is easy to individually distinguish semiconductor chips of the same type such as those having a semiconductor chip identification pattern A as shown in FIGS. 1 and 2. Therefore, for example, in a semiconductor device used at a high frequency such as a microwave band where a difference between individual low-frequency characteristics affects the overall characteristics of the semiconductor device, since individual chips can be identified, the low-frequency characteristics can be easily determined. Characteristics can be matched. Further, it becomes possible to manage the mutual conductance of the field effect transistor in the chip, the value of the drain / source saturation current of each chip, and to select and use a higher withstand voltage.

FIG. 3 is a plan view of a semiconductor chip for explaining another embodiment of the present invention. As shown in the drawing, in this embodiment, since the reference number pattern 20 is formed on the semiconductor material portion 3, there is an advantage that the area of a region that can be used for forming a circuit in the semiconductor chip 2 is increased. In this embodiment, in addition to forming the reference number pattern 20 on the semiconductor material itself,
It is also possible to form the reference number pattern 20 by leaving a protective film, a passivation film, a conductor layer, polyimide, and the like in an appropriate shape on the semiconductor material portion 3.

In recent manufacture of semiconductor wafers having fine patterns, a method (stepper) of repeating partial exposure of a semiconductor wafer is used. On the other hand, in order to electrically connect the semiconductor chips, the protective film or passivation film 4 on the terminal electrode 10 must be removed. The exposure mask used at this time is a method of exposing the entire wafer at once because the pattern to be exposed is not fine and the marks used for identification are made thick for easy viewing (for example, using a contact mask. Exposure) can be used. As an example of the manufacturing method, there is a method in which a mask used for opening the protective film or the passivation film is used as a contact mask as described above and a mark that can individually identify each chip is used. According to this method, there is also a feature that the mark attached to the chip is located at the uppermost layer, so that it is easy to see.

Since each of the chips has an identifiable mark as described above, it is possible to realize a method of comprehensively judging test data and selecting a chip after dividing the chip individually.

In both of the embodiments described above, the mark such as the collation number pattern is represented by characters. However, the present invention is not limited to this, and may be an appropriate symbol or a combination of characters and symbols.

〔The invention's effect〕

As described above, the present invention easily distinguishes individual semiconductor chips formed in the same wafer by providing a reference number pattern on each semiconductor chip so that semiconductor chips of the same type can be individually distinguished. Therefore, detailed characteristics of individual semiconductor chips can be managed.

Because each chip has a distinguishable mark,
After chip division performed after a chip test, test data is comprehensively determined, and a better chip can be used preferentially. Further, in the case of a GaAs semiconductor wafer that is mechanically fragile, there is also an effect that a scratch on the chip surface that causes chip breakage and chipping including non-defective chips during chip division can be avoided.

[Brief description of the drawings]

FIG. 1 is a plan view of a semiconductor wafer for explaining one embodiment of the present invention, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a semiconductor for explaining another embodiment of the present invention. It is a top view of a chip. DESCRIPTION OF SYMBOLS 1 ... Semiconductor wafer, 2 ... Semiconductor chip, 3 ... Semiconductor material part, 4 ... Protective film or passivation film, 20 ...
... verification number pattern, 30 ... semiconductor chip identification pattern.

Claims (3)

(57) [Claims] 1. A semiconductor wafer on which a plurality of types of semiconductor chips are formed on the same substrate, wherein said plurality of types of semiconductor chips each have a first mark which can be individually recognized. And a second mark provided on each of the semiconductor chips so that the plurality of types of semiconductor chips can be recognized for each type. 2. A method for manufacturing a semiconductor wafer according to claim 1, wherein a mark for recognizing each semiconductor chip is provided in a mask for opening an electrode portion of the chip, and the semiconductor wafer is manufactured using the mask. . 3. The method according to claim 1, wherein test data of the semiconductor wafer is comprehensively determined, and a chip having better characteristics is preferentially selected and used by using a mark for recognizing each semiconductor chip. Item 4. The method for selecting a semiconductor chip according to Item 1.