JPH01211935A - Probing device for wafer - Google Patents

Abstract

PURPOSE:To measure the pellets on wafers efficiently by a method wherein only the pellets on several sample wafers are measured to set up assumed defective distribution regions so that the measurement of larger regions out of acceptable and defective pellets may be skipped over. CONSTITUTION:Within the title probing device 2, when multiple semiconductor pellets on multiple wafers 1 to be tested are successively probed to test the electric characteristics, if a pellet is disclosed to be defective, the pellet is marked with a defective mark. Besides, a mapping memory 8 storing the defective frequency distribution region of the pellets corresponding to the wafer shape as well as an assumed region setting up control circuit 12 setting up the assumed defective distribution regions by binary coding said regions in the region with the frequency exceeding specified value and the other region with the other frequencies are provided. Furthermore, a pellet measurement skip control circuit 13 making the defective marks only without performing the measurement process when the pellet positions of wafers 1 to be tested in the same lot to be measured after setting up the assumed defective distribution region are contained in the assumed defective distribution is provided. Through these procedures, the pellet can be measured efficiently even if the pellet yield of semiconductor wafers is unfavorable.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a wafer probing apparatus.

[Conventional technology]

With the remarkable development of ICs in recent years, IC testers that determine whether pellets are good or bad, and probing equipment that uses probes to measure pellets in wafers, are required to be more sophisticated and expensive. It has become.

On the other hand, in response to the demand for lower prices for ICs themselves, ICI
There has been an increasing demand for improvements in measurement technology, such as shortening the measurement time per piece, simultaneous measurement of multiple pieces, and shortening the machine index.

Conventional probing equipment includes a handling mechanism for simultaneously measuring the electrical characteristics of one or more pellets on a wafer, and an electrical characteristics testing and evaluation device (hereinafter referred to as IC).
It was a device that received a defect signal from a tester (called a tester) and added a defect mark to each pellet on the wafer using a certain method.

[Problem to be solved by the invention]

The above-mentioned wafer probing equipment basically tests the electrical characteristics of all pellets, so in the case of wafer rods that have a poor yield, such as wafer pellets during the IC development stage, it is difficult to measure them. There were problems such as it took an unnecessarily long time, and feedback of purchasing data to the previous process was delayed, thereby delaying IC development.

Furthermore, if a large number of probing devices are installed as a measure against low yield, the pellet yield of IC will generally improve at the mass production stage, so there is a problem that a large number of specialized probing devices will become redundant equipment.

SUMMARY OF THE INVENTION An object of the present invention is to provide a wafer blowing apparatus that can efficiently measure semiconductor wafers even when the pellet yield is poor.

[Means to solve the problem]

The wafer probing apparatus of the present invention sequentially bombards a plurality of semiconductor pellets on a plurality of wafers to test electrical characteristics, and if the pellets are defective, a defective mark is added to the pellets. In the blowing device, a mapping memory unit stores a failure frequency distribution area of pellets of a sample number of the tested wafer in correspondence with the wafer shape; an estimated area setting control circuit that binarizes the estimated failure distribution area to set an estimated failure distribution area, and a position of a pellet of the same rod to the tested wafer to be measured after setting the estimated failure distribution area is within the estimated failure distribution area. In this case, the measuring area control section is provided with a pellet measurement skip control circuit that only adds the defect mark without performing measurement.

〔Example〕

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

FIG. 1 is a block diagram of one embodiment of the present invention.

The wafer blowing device 2 has a glove 9a that is applied to the pellet on the wafer under test l, and a pellet measurement section 9 that is connected to the IC tester section 3, and controls the transportation, recognition, stage control, etc. of the wafer under test l. a glober control section 7 to perform
The measurement area control section 15 which receives the defective signal SF 1 and whose output end outputs a skip signal Ssx is provided.

The measurement area control section 15 includes an estimation area setting circuit 12 that receives the defect signal SF and sets an estimation area of pellet defects, and a mapping memory section 8 that stores the distribution area data SD.
and a measurement skip control circuit 13 which inputs a prober control signal Sc and a map signal Sns and outputs a measurement skip signal Ssx.

Next, a procedure for measuring pellets using a wafer blowing device will be described.

FIGS. 2(a) to (C) are states of the mapping memory section corresponding to the initial failure frequency distribution area after sample testing and the estimated failure distribution area of wafer rods for explaining the operation of the blocks in FIG. 1. It is a diagram.

First, a sampling test is performed on three wafers in order to set an estimated failure distribution area for a wafer loft consisting of a plurality of wafers to be tested.

The properr control signal Sc sequentially outputs the carrier signal S T I recognition signal SN and the stage control signal Ss, and the wafer to be tested is set in the pellet measuring section 9, and the probe 9a is applied to the specified pellet.

If the constant circuit 11 is determined to be defective in accordance with the standard value,
The defective signal Sv is supplied to the defective mark generation circuit 14 and the measurement area control section 15.

The defective mark signal SM drives the defective mark generator, adds some defective mark to the pellet concerned, and then moves on to measuring the next pellet in sequence.゛At the same time, the defective signal SF is sent through the estimation area setting circuit 12 (G in Fig. 2)
As shown in FIG. 3, the number of defects "1" is stored in the corresponding pellet position on the mapping memory section 8 which has a wafer area whose initial state is set to "0" as a non-defective product.

Three wafers are sampled, measured, and the cumulative defect count (θ
~3) is memorized.

As shown in FIG. 2(b), the wafer area W1 is
It is divided into a non-defective pellet area of 0'' and a defective frequency distribution area A of 1 to 3''.

Next, in advance, the defective frequency “l” or less is classified as a non-defective product “0”, and 12”
The process of binarizing the above into defective "l" is performed by the estimation area setting circuit 12, and as shown in FIG. Make a mapping memo for area W2.

According to the sample test, if the area of the estimated defective distribution area B in the wafer area W2 is 50% or more, if the position of the pellet to be measured corresponds to the estimated defective area B, the pellet to be measured is skipped without being measured and declared defective. Add marks and proceed to measuring the next pellet.

Further, at the position of the non-defective product corresponding to outside the B area, the pellet to be measured is measured, and only when there is a defective signal SF from the work C tester section 3, a defective mark is added, and the process proceeds to the next pellet.

Therefore, the measurement of most of the pellets in the tested quafer, which have a high probability of being defective, is skipped, and the
Since only the pellets corresponding to the non-defective area of the 0% upper memo area are measured, the test efficiency is improved by about twice.

The above example shows a case where the number of non-defective areas is small, but conversely, if there are more non-defective areas than defective areas, the non-defective areas of this wafer rod are not measured and are skipped. Only the corresponding pellets within the distribution area B are measured, and only when there is a defective signal SP, a defective mark is added and the process proceeds to the next pellet.

Every time the wafer rod changes, the estimated defective distribution area is set using the sample wafer described above.

〔Effect of the invention〕

As explained above, the present invention measures only the pellets on several sample wafers, sets the estimated defect distribution area, skips the measurement of areas with large areas among good and defective, and then measures the pellets on subsequent wafers. By greatly increasing the efficiency of pellet measurement, it is possible to expect early improvement in quality and promotion of IC development, which is a significant effect.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2(a)
-(C) are state diagrams of the mapping memory section corresponding to the initial failure frequency distribution area after the sample test and the estimated failure distribution area of the wafer date for explaining the operation of the block in FIG. 1. l... Wafer under test, 2... Wafer 8 Probing device, 3... IC tester section, 8
...Mapping memory section, 9...Bellet measurement section, 9a...Glove, 11...
... Good/bad judgment circuit, 12... Good frequency distribution area, B... Estimated defective distribution area. Agent Patent Attorney Otoyo Uchihara Illustrator

Claims (1)

[Claims] In a wafer probing apparatus that sequentially applies a probe to a plurality of semiconductor pellets on a plurality of wafers to be tested to perform an electrical characteristic test and adds a defective mark to the pellet if the pellet is defective, the sample of the wafer to be tested is a mapping memory unit that stores a defective frequency distribution area of the number of pellets corresponding to the wafer shape; and an estimated defective distribution area is set by binarizing the defective frequency distribution area into a predetermined frequency or higher and other frequencies. an estimated area setting control circuit, and if the position of the pellet of the test wafer of the same rod to be measured after setting the estimated failure distribution area is within the estimated failure distribution area, only the addition of the failure mark is performed without measuring; A wafer probing apparatus characterized by having a measurement area control section provided with a pellet measurement skip control circuit.