JPS6024031A - Semiconductor wafer prober - Google Patents

Abstract

PURPOSE:To enable to automatically inspect the addition of defective marks to defective chips by a method wherein the result of quality judgement of each wafer chip is stored to a wafer map, and the defective mark is recognized by a recognition device. CONSTITUTION:The electric characteristics of a wafer chip are measured by contact of a probe card needle with a chip pad on the wafer positioned at a fixed position. The quality is judged from the measured result of electrical characteristics obtained. Then, the defective mark is added to the wafer chip judged as defective by a defective signal from a tester. Thereafter, the shape of defective marks added to this wafer is recognized by the recognition device, and the measured result of wafer chips in the wafer is stored as the wafer map. Next, the shape of defective marks recognized by the device is compared with that measured; it is judged as a defective wafer chip in the case of agreement. Finally, the omission of defective mark puncing to the defective wafer chips is discovered from the stored result in the wafer map, and then a defective mark is added again to this chip.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor wafer measuring device used in a semiconductor wafer manufacturing process, and particularly to a semiconductor wafer prober.

Conventional semiconductor wafer chips are usually formed on several hundred sides on one wafer at the same time, and are individually separated after measurement. Of the divided chips, only good chips are taken out and packaged to complete an integrated circuit (IC) product.

To explain this in more detail, in the process of measuring the electrical characteristics of chips within a wafer, an input signal is sent to the chip from a device called a tester, which determines whether the chip is good or bad. It receives the output signal and judges the output signal to determine whether the chip is a good product or a defective product.

Normally, the above input/output signals are sent from the tester or sent to the tester by a stylus (hereinafter referred to as probe card needle) placed on the probe card to match the position of the electrode (hereinafter referred to as pad) provided on the chip. sent. The tester receives a signal from the chip and determines whether it is a good product or a defective product, and if it is a defective product, sends a defect signal to the semiconductor wafer prober. A semiconductor wafer prober operates a device called an inker (marker) that marks the surface of a chip according to the above-mentioned defect signal, and adds a mark to the surface of a defective wafer chip.

Conventionally, such an inker has one or more needles provided in the center of a semiconductor wafer prober. In this case, the tester adds a mark to the surface of a chip judged to be defective in two ways: firstly, it is done immediately after measuring a single chip, and secondly, the tester adds a mark to the surface of a chip judged to be defective. (hereinafter referred to as mapping) 1. , and store it in a storage area (hereinafter referred to as wahammap),
When all the chips have been measured, chips that are determined to be defective may be marked again at another location.

The mechanism of the inker mentioned above is: (1) A type in which ink is attached to the chip surface using a needle.

There are two types: (1) which damages the chip surface by hitting it with a hard needle, and (2) which melts the chip surface by irradiating the chip surface with laser light.

In any of the above three types of marks, when the inker hits the needle toward the chip during marking, one of the functions of the semiconductor wafer prober is that current passes through it and it becomes an electromagnet. The operation of the inker when energized can be understood. However, since it is not confirmed whether the mark has actually been added or not, if the inker is activated when the ink runs out in (2), the mark may not have been added. As a result, even a defective chip is judged to be a good chip. In addition, regarding the long mold type (■) in which the chip surface is damaged by hitting it with a hard needle,
When the tip of the needle breaks and cannot reach the wafer chip, a defective chip is similarly judged to be a good chip. The same is true for the method (2) in which the chip surface is irradiated with laser light to melt the chip surface, and there are cases where the laser light is not emitted due to damage to the tip of the chip. Therefore, even a defective chip is judged to be good.

In order to solve these problems, the purpose of the present invention is to automatically recognize and confirm whether or not the defective wafer chip is marked with a defective mark by an inker when the tester determines that the defective wafer chip is a defective wafer chip. An object of the present invention is to provide a semiconductor wafer prober that can perform the following steps.

One embodiment of the present invention will be described below with reference to the drawings.
1 is a block diagram showing an outline of the semiconductor wafer prober of the present invention, FIG. 2 is a plan view showing the surface of a semiconductor wafer, and FIG. 3 is a wafer map diagram.

In the semiconductor wafer prober of the present invention, a semiconductor wafer, which is an object to be measured, is placed on a mounting table and fixed by vacuum suction. This mounting table is automatically operated by a drive mechanism that moves in the horizontal X- and Y-axis directions and in the vertical Y-axis direction. The probe card needle is brought into contact with the top pad of the chip on the wafer positioned at a predetermined position, and measurement is performed. This probe card needle has a measuring mechanism that connects to a tester and measures whether the wafer is good or bad. This tester measures individual wafer chips through a mechanism such as the positioning of a semiconductor wafer prober, and has a judgment function that determines whether the wafer chips are good or bad based on the results of measuring the electrical characteristics of the obtained wafer chips. .

The result of the tester measurement determined in this way is marked with a defective mark by the defective signal from the tester.
It is displayed on the wafer by a marking mechanism. after that,
The recognition device recognizes the shape of the defect mark on the wafer as a whole (=l), and the measurement results of the wafer chips within this wafer are stored as a wafer map. Of course, each individual mechanism itself can be a known one.

In the semiconductor wafer prober of this invention.

(The X-axis and Y# force direction address signals in the D drive mechanism and the good/bad signals in the chip measurement results by the tester are stored in a control mechanism called a wafer map as measurement information that associates each chip with an address.) As shown in Fig. 2, the defective chip 8 on the wafer is displayed by the defective signal of the tester and mapped to addresses in the X-axis and Y-axis directions.■ Information stored in the wafer map above. Based on this, an inker is operated on the surface of the defective wafer chip within the wafer to add a mark.Up to this step, conventional techniques are used.

Note that if the added defective mark is recognized by a recognition device, the information from the recognition may be mistaken for dust, so first, wafer probing memorizes the shape of the defective mark in advance and uses it as a basic defective mark. It is called. This basic defective mark is compared with the added defective mark, and if the shape is along the basic defective mark, it is a defective wafer chip that corresponds to the measurement result by the tester, and a defective mark has been added to the surface of the wafer chip. Things become clear. In addition, this defective mark is automatically recognized after the chips in the wafer are measured using a semiconductor wafer prober, and there is a process in which only good wafer chips are assembled. Therefore, it is extremely useful to automatically recognize the size of defective marks in the wafer probing process.

If the measurement result indicated by the wafer map is a defective wafer chip and the recognition device does not recognize a defective mark, a defective mark is added to the surface of the defective wafer chip again by the defective signal. Thereafter, the defective mark is recognized by the recognition device again, and as a result, the defective mark is recognized.

In addition, if the above-mentioned inability to recognize continues several times, for example, if a function is installed to notify the operator, the operator can always check that only defective wafer chips have been marked with defective chips by filling ink. Then, the entire process of the semiconductor wafer prober is completed.

This invention is configured as described above.

A defective mark is added to all defective wafer chips except for good semiconductor wafer chips, and since the defective mark is used as a guide when sorting wafer chips, the quality of semiconductor wafer chips is highly reliable. product is obtained. It is also very effective in automation.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing an embodiment of a semiconductor wafer prober of the present invention, FIG. 2 is a plan view showing an example of a defective wafer chip on the wafer surface, and FIG. 3 is a schematic diagram for explaining a wafer happe. It is. /09. Semiconductor wafer 810. Defective wafer chip 1st
Figure 2 Figure 3

Claims (1)

[Claims] 1. A semiconductor device in which electrical characteristics are measured by bringing a probe card needle into contact with wafer chips placed on a wafer, and defective marks are added to the surface of defective wafer chips based on the measurement results. The wafer prober maps the results of measuring whether each wafer chip on the wafer is good or not and stores it in the wafer map, and the recognition device recognizes the defect mark actually added to the defective wafer chip and stores it in the wafer map. By comparing the information detected by the recognition device with the information recognized by the recognition device, a defective mark is found on the defective wafer chip, and the defective mark is again attached to the defective wafer chip to confirm the defective mark. A semiconductor wafer prober featuring: