JPH0638439B2 - Semiconductor device testing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] A reverse cover chip in which only pads are exposed and the other is covered with an insulating film is provided with a reverse cover chip in which only the pads are covered with an insulating film and the other is exposed. This is a test method in which the displacement of the probe is detected by the cover chip.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe test method among semiconductor device test methods.

2. Description of the Related Art Conventionally, in a semiconductor device such as an IC, a large number of elements are formed on a semiconductor wafer, and a probe (probe) is brought into contact with each other before dividing this into individual chips to determine whether the electrical characteristics of these elements are good or bad. , Which is called a wafer probe test.

This is because if a probe test is performed in advance in a wafer state, the man-hours for incorporating the defective chip into the package and the material for the package are saved. A yield close to is obtained.

Therefore, the probe test is an extremely important process, and it must be tested with great care so that the quality of the IC is not damaged.

[Prior Art] FIG. 3 is a schematic sectional view of a head portion of a probe test, in which 1 is a wafer, 2 is a probe card, 3 is a movable stage, and 4 is a test station including accessory parts. The probe card 2 is provided with a large number of probes (several tens to hundreds of tens of probes), and the probe card 2 is replaced depending on the type of IC. When replacing the probe card, the test station 4 is lifted by the arm. Further, the wafer is automatically moved together with the movable stage 3 and the chips are sequentially tested. At that time, a cavity is provided in the central portion of the test station 4 so that it can be monitored by a microscope (not shown) from above. Has been.

Next, FIG. 4 shows a plan view of one chip (normal chip) in the test wafer, and FIG.
In the overall plan view, 11 is an aluminum (A1) pad for connecting a bonding wire, and 12 is a cover insulating film (covering insulating film) made of a silicon dioxide (SiO ₂ ) film.
Is. Although only 16 pads 11 are shown in the figure, several tens to several hundreds of pads corresponding to several tens to hundreds of tens of probes are actually provided.

FIG. 4B shows a plan view of one pad 11 portion in the chip, and an aluminum wiring 13 connected to the pad 11 is provided below the SiO ₂ film 12. Further, the aluminum film 14 is widely patterned around the pad in the pad 11 portion, and the aluminum film in the peripheral portion is replaced with the SiO ₂ film.
12 is in a covered state. The size of such a pad is, for example, about 100 μm square.

Thus, the test wafer provided with a large number of such chips is sent at high speed by the movable stage, and the chips are tested one after another.

[Problems to be Solved by the Invention] However, in such a probe test, the contact position of the probe was displaced, the cover insulating film was touched and damaged, and further, the aluminum film around the lower pad was contacted. When the test is performed in the state, the test is completed without any trouble. However, the contacting cover insulating film is damaged, and a crack runs from there, so that it cannot serve as a cover film. This damage is extremely serious because impurity ions in the air enter the inside of the wafer and contaminate the wafer, resulting in deterioration of IC quality, reliability, or yield.

Therefore, at present, damage and cracks in the cover insulating film are detected by visual inspection, but this requires a lot of man-hours and time, and the wafer with the damaged cover insulating film is removed. , Will reduce the yield.

The present invention proposes a test method that eliminates such drawbacks.

[Means for Solving Problems] The purpose is to expose only the pad for wire connection,
One or a plurality of chips in which other parts are covered with an insulating film, and only the pads are covered with the insulating film to expose other parts at a desired chip position of a semiconductor wafer arranged in an array. The reverse cover chip is provided, and the probe is brought into contact with the reverse cover chip in the probe test of the semiconductor wafer to detect the displacement of the probe, thereby achieving the semiconductor device test method.

[Operation] That is, a chip provided with a reverse cover is provided in a required chip, and the reverse cover chip is subjected to a probe test at an appropriate time during the initial test and other tests to detect the displacement of the probe. Then, if there is a displacement, the probe position is corrected.

Then, the positional deviation of the probe is detected without relying on the visual inspection, and the cover insulating film of the required chip is not damaged.

[Examples] Hereinafter, examples will be described in detail with reference to the drawings.

FIG. 1 is a plan view of an inverse cover chip according to the present invention, in which 21 is an insulating pad covered with a SiO ₂ film, and 22 is a conductive region where an aluminum film is exposed.

A plan view of a wafer provided with such reverse cover chips is shown in FIG. 2. In this example, four reverse cover chips 20 are provided in the wafer, and the other chips are ordinary chips.
Is 10. Such a reverse cover chip 20 is a normal chip
Can be formed at the same time as 10. That is, a normal chip
Reverse cover chip, deposited simultaneously with 10 aluminum films
In No. 20, the aluminum film is left as it is without forming a wiring pattern. Next, a cover film made of a SiO ₂ film is attached at the same time as the normal chip 10
When opening the pad 11 of 10, the SiO _{2 of the} reverse cover chip 20
The film is also patterned at the same time.

A plan view of a wafer provided with a plurality of reverse cover chips formed in this way is shown in FIG. Attach this to the probe test head as shown in FIG.
The probe is brought into contact with the reverse cover chip 20. At this time, the conductive region 22 where the aluminum film of the reverse cover chip 20 is exposed
Is kept at the same potential as the stage through the wafer substrate.
It is possible to keep the wafer substrate and the aluminum film in contact with each other by the treatment before depositing the aluminum film on the entire surface.

Then, when the probe is brought into contact with the probe, if the position of the probe is normal, all the pads are insulating pads, so that it is output that the measurement is impossible. That way, the normal tip
Start 10 tests. On the other hand, if the position of the probe is misaligned, it is output from that pad as being short-circuited with the stage. At that time, the position of the probe is readjusted, and the probe is brought into contact with the reverse cover chip 20 again to detect the possibility of the position. Since the recent probe test apparatus can arbitrarily specify the measuring chip, such a check is always possible.

Thus, when performing a probe test on one wafer,
The probe position is detected by contacting the reverse cover chip 20 every predetermined number of chips. Alternatively, first, the probe positions are detected by the four reverse cover chips 20 in one wafer. Alternatively, when the accuracy of the probe may be a little poor, the reverse cover chip 20 detects the probe position for every 3 to 4 wafers.

On the contrary, when the accuracy of the probe is extremely high, the area of the insulating pad 21 is slightly smaller than the area of the pad 11 instead of the insulating pad 21 of the reverse cover chip 20 having the same area as the pad 11 of the normal chip 10. I'll do it. For example, 10μ both vertically and horizontally
m Provide a smaller insulating pad. Then, the positional accuracy of the probe can be further improved.

According to such a test method of the present invention, there is no need for the conventional probe displacement inspection (inspection for damage or crack of the cover insulating film) by visual inspection, and the reliability of the test is improved.

[Effects of the Invention] Therefore, as is apparent from the above description, according to the present invention, it is possible to eliminate the visual inspection for damage or cracks in the cover insulating film, and to improve the reliability of the test and the test yield. It is a great effect that can be improved.

[Brief description of drawings]

 FIG. 1 is a plan view of a reverse cover chip relating to the present invention, FIG. 2 is a plan view of a wafer according to the present invention, FIG. 3 is a schematic sectional view of a probe test head, and FIG. 4 is a normal chip plane. It is a figure. In the figure, 10 is a normal chip, 11 is a pad, 12 is a cover insulating film, 13 and 14 are aluminum wirings and films under the insulating film, 20 is a reverse cover chip, 21 is an insulating pad, and 22 is a conductive area. There is.

Claims (1)

[Claims] 1. Exposing only a pad for wire connection,
One or a plurality of chips in which other parts are covered with an insulating film, and only the pads are covered with the insulating film to expose other parts at a desired chip position of a semiconductor wafer arranged in an array. The reverse cover chip is provided, and the probe is brought into contact with the reverse cover chip in the probe test of the semiconductor wafer to detect the displacement of the probe, and the semiconductor device testing method.