JPH01214133A - Marking of semiconductor wafer - Google Patents

Abstract

PURPOSE:To relieve any chip, which has once been regarded as being bad by recording, without directly making the surface of a bad chip, the location of the bad chip on another medium, and utilizing the record upon removing thereafter the bad chip. CONSTITUTION:A water 1 to be tested is placed on a stage 7, and a measuring probe 3 is applied to each step each time the stage 7 is moved for electrical testing. Thereupon, a recording plate 4 is placed on a stage 8 which is made movable in the same manner as the stage 7. A position on the recording plate, which location corresponds to a chip in testing, is made to be located under a marker 2 at all times. When a tested chip is bad, the recording plate 4 is marked by the marker 2 with a mark indicative of that fact. The position of the bad chip is sent to a later process using the recording plate 4 as a medium, and the bad chip is removed on the basis of the information recorded on the recording plate 4. According to the marking method, a chip, which has once been decided bad, can be retrieved if it is good as it is re-tested.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides a method for testing semiconductor chips in a wafer state.
This invention relates to a method for recording defective chips.

[Conventional technology]

After testing semiconductor chips in the wafer state, marks are placed on defective chips, the wafer is separated into individual chips, and the chips with the defective marks (defective dots) are removed before assembly. be removed. As shown in FIG. 3, defective chips have defective dots, and the dots are created by scratching the surface of the chip with a needle or burning the surface with a laser.

[Problem that the invention seeks to solve]

Conventionally, the method of indicating defective chips (dotting method) is to scratch the surface of the chip with a needle or burn it with a laser, making the chip completely defective (damaging).
I plan to remove it later.

In this case, the product becomes completely defective, resulting in the following problems. During the test, the test equipment may malfunction during the test.
If the test conditions or method were unstable, what should have been a good product was marked as defective, marked as defective, and even if the defect was discovered and the test was attempted again, the chip could not be salvaged. I can't take medicine.

Means for Solving Problem C] Instead of the conventional method of directly marking the surface of a defective chip, the method of the present invention records the location of the defective chip on another medium, and when removing the defective chip later, the method records the location of the defective chip on another medium. The records shall be used for this purpose.

〔Example〕

Next, the present invention will be explained using the drawings.

FIG. 1 shows a recording plate for recording the position of a defective chip, and on the recording plate there is drawn a wafer, which is an object to be tested, and a figure of the same size and shape as the chip on the wafer. These do not have to be exactly the same size as long as the positional relationship of the chips can be understood.

In this method, a defective mark is placed on the recording plate at a position corresponding to the defective chip, and the defective chip itself is not marked.

FIG. 2 is a conceptual diagram of a test system in a wafer state. Here, the wafer to be tested is placed on a stage 7, and each time the stage 7 moves, the measurement probe 3 is applied to each chip to perform an electrical test.

At this time, the recording plate 4 is placed on the stage 8, but the stage 8 is made to move in the same way as the stage 7.
The location on the recording board corresponding to the chip under test is always located below marker 2.

If the chip tested there is defective, marker 2
Simply put a mark on the recording plate to indicate that it is defective.

In this way, the location of the defective chip is marked on the recording plate. The location of the defective chip is sent to a subsequent process using this recording plate as a medium, and after the wafer is cut into chips, the defective chip can be removed based on the information on this recording plate.

In the embodiments described above, a recording plate was used as a medium, and defective chips were recorded using hardware called a recording plate, but as a second embodiment, a method using software will be described.

In FIG. 2, a storage device is connected to the test device. Here, the location of the defective chip may be stored in the storage medium of the storage device. Position information to subsequent processes is sent by this storage medium. A magnetic disk can be used as an example of a storage medium.

〔Effect of the invention〕

As explained above, the present invention does not directly impact the defective chip and does not damage the chip, so even if some defect is found after the test, the cause of the defect is removed and then
Even if the product is found to be defective, it can be retested and if found to be good, it can be salvaged.

Another effect is that when trying to automatically remove defective chips after separating them into chips, the conventional method of automatically recognizing and removing needle marks and laser damage marks on the chips requires a recognition device. However, the method of the present invention can be achieved with a simple recognition device (recognizing marks on a recording board), and the method using a storage device does not require the recognition device itself. First, defective chips are selected by software.

[Brief explanation of the drawing]

FIG. 1 is for recording the position of a defective chip, which is used in the method of the present invention, and the shapes of the wafer and chips are drawn so that the positional relationship of the chips on the wafer to be measured can be recorded. Here, 1-... Defective recording plate, 2... Wafer chip figure, 3... Defective mark, 2nd
The figure is a conceptual diagram of a test system for realizing this method. Here, 1... wafer to be measured, 2...-
・Defective marker, 3-...Test probe, 4-
...Defective recording board, 5...Testing device, 6-.
... Marker control unit, 7 ... Wafer stage, 8 ... Defective recording plate stage, 9 ...
...Storage device, FIG. 3 is a diagram of a wafer with defective dots by the conventional method. Here, 1... wafer, 2...
・Chip on wafer, 3...Chip with defective dots. Agent Patent Attorney Oto Uchihara

Claims (1)

[Claims] A marking method characterized in that when a semiconductor chip on a semiconductor wafer is defective, it is recorded on another medium instead of directly marking the defective point on the chip.