JPH01171236A - Prober apparatus - Google Patents

Abstract

PURPOSE:To ensure contact between a plurality of probes and a wafer to be tested, by giving suttle supersonic vibration to the wafer to be tested, detecting the vibration by means of pickups mounted on the probes and obtaining a logical product of a plurality of outputs detected by the probes by means of an AND circuit. CONSTITUTION:A supersonic oscillator 4 is actuated and a supersonic vibrator 3 is excited to give suttle supersonic vibration to a wafer to be tested 1. A pair of probes 5, 6 are put close to pads on the wafer 1. When the probe 5 is contacted with the wafer 1, the supersonic vibration of the wafer 1 is transmitted to the probes 5, 6. The supersonic vibration is converted into electrical signals by supersonic pickups 7, 8, and amplified so that detecting circuits 9, 10 detect supersonic vibration on the probes. Logical product of the outputs from the detecting circuits 9 and 10 is obtained by an AND circuit 11. Output from the AND circuit 11 is obtained when both the probes 5 and 6 are contacted with the wafer 1. Accordingly, nondefective wafers 1 can be selected correctly by operating a measuring device only when output is obtained from the AND circuit 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an LSI testing device, and more particularly to a P/W test, that is, a prober device used for testing a semiconductor wafer.

[Conventional technology]

Generally, LSI (Large 5cale In
A large number of LSI chips are formed on a semiconductor wafer in the manufacturing process (tegration), and the wafer is first sorted to be non-defective before it is cut. This P/W test (Probing by Wefer
), the chip under test is connected to the LSI tester using a probe.

That is, this was done by electrically connecting the LSI tester and the chip under test by placing the probe of the prober on the human output pad of the LSI chip.

[Problem that the invention seeks to solve]

By the way, in the conventional blower device mentioned above, P
/W Before performing the test, the stage on which the semiconductor wafer to be tested is placed is first positioned. This stage is
A dummy wafer that is movable both horizontally and vertically and has the same thickness as the wafer under test is used to determine the vertical position where the probe reliably contacts the wafer under test.

In this positioning operation, contact between the dummy wafer and the probe is confirmed by the presence or absence of electrical continuity between the probe and the dummy wafer. In an actual P/W test, a wafer to be tested is placed on a stage, and the stage is moved to a predetermined position according to the above-described procedure to set up a probe. .

At this time, contact between the wafer and the probe cannot be directly confirmed. Therefore, in the conventional P/W test, even if there is no abnormality in the wafer, the test may fail due to poor contact of the probe.

Such a risk increases as the number of pins on an LSI increases. Furthermore, it is difficult to determine the cause of a test failure due to poor contact of the probe, and the P/W test requires a large amount of time.

SUMMARY OF THE INVENTION An object of the present invention has been made in view of the above-mentioned drawbacks of the conventional art, and it is an object of the present invention to provide a prober device that can ensure the contact between a wafer under test and a probe, and can detect only defects in a semiconductor wafer. It is in.

[Means for solving problems]

The blower device according to the present invention includes a stage that is movable horizontally and vertically and that fixes a semiconductor wafer under test, an ultrasonic vibrator attached to this stage, an ultrasonic oscillator that excites the same, and a probe. , an ultrasonic pickup attached to the probe, a detection circuit that amplifies the output signal from the pickup and detects the ultrasonic signal, and an AND circuit that performs the logical product of the output signals of the plurality of detection circuits. to ensure that the wafer is in contact with each probe. Therefore, failure of the test due to poor contact of the probe can be prevented.

〔Example〕

An embodiment of the present invention will be described below with reference to the accompanying drawings.

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

In the figure, the blower device includes a stage 2 on which a wafer under test 1 is placed, an ultrasonic vibrator 3 that vibrates the stage 2, an ultrasonic oscillator 4 that excites the ultrasonic vibrator 3, and a probe. 5.6, an ultrasonic pickup 8.9 attached to each probe, detection circuits 9 and 10 connected to the ultrasonic pickup, and an AND which is one of the logical quantities connected to the detection circuit. It is composed of a circuit 11 and the like. Further, the probes 7 and 8 are connected to a measuring device or an IC tester (not shown) to measure the characteristics of the LSI chip. On the other hand, the AND circuit 11 is connected to a measuring device or an IC tester (not shown), and detects whether all the probes are in proper contact with the wafer under test 1, and generates a signal only when the probes are in proper contact with the wafer under test 1. .

Next, the procedure for using the prober device of this embodiment will be explained. First, the wafer 1 to be tested is fixed to the stage 2 with a clamp (not shown) with the stage 2 positioned lower than the height of the tip of the probe 5.6. In this state, the ultrasonic oscillator 4 is activated and the ultrasonic vibrator 3 is excited to apply subtle ultrasonic vibrations to the wafer 1 under test. Next, the stage 2 is moved upward, and the two probes 5 and 6 are brought close to the pads of the wafer 1 to be tested that have been positioned in advance. When the wafer under test 1 and the probe 5 come into contact here, the ultrasonic vibrations of the wafer under test 1 are transmitted to the probes 5 and 6. This ultrasonic vibration is caused by the probe 5
．． The signal is converted into an electric signal by an ultrasonic pickup 7.8 mounted on the probe 6, and then amplified, and the presence or absence of ultrasonic vibration of the probe is determined by detection circuits 9 and 10.

The presence of ultrasonic vibration means that the probe is on the wafer under test 1.
This means that it is in contact with. In this embodiment, the AND circuit 11 generates the logical product of the detection circuit 9 and the detection circuit 10, and the output from the AND circuit 11 is not produced until both the probe 5 and the probe 6 come into contact with the wafer under test 1. (can be given.

Therefore, by operating the measuring device only when there is an output from the AND circuit 11, it is possible to accurately select non-defective wafers I to be tested.

Although the above embodiments have been described with reference to the case where there are two probes, the present invention is not limited to this and may include a plurality of probes, specifically 10 or more probes.

〔Effect of the invention〕

As explained in detail above, the blower device of the present invention applies minute ultrasonic vibrations to the wafer under test, detects this using an ultrasonic pickup attached to a probe, and detects the ultrasonic vibrations obtained from a plurality of probes. By calculating the logical product of a plurality of detection outputs using an AND circuit, contact between the plurality of probes and the wafer under test can be ensured. Therefore, wafer inspection can be performed efficiently. Furthermore, even if the wafer is normal, the test will not fail due to poor contact with the probe.

[Brief explanation of the drawing]

The figure is an equipment configuration diagram of a prober device showing an embodiment of the present invention. 1... Wafer under test, 2... Stage, 3... Ultrasonic transducer, 4... Ultrasonic oscillator, 5.6... ...Probe, 7.8...Ultrasonic pickup, 9.10...
...Detection circuit, 11...AND circuit

Claims (1)

[Claims] A stage that is movable horizontally and vertically and fixedly places a semiconductor wafer under test, an ultrasonic transducer attached to this stage, an ultrasonic oscillator that excites this ultrasonic transducer, and a stage that is in contact with the semiconductor wafer. a plurality of probes, an ultrasonic pickup attached to these probes, a detection circuit that amplifies the signal detected by the ultrasonic pickup and detects the ultrasonic signal, and a plurality of detection circuits. A prober device comprising a logic circuit that obtains an AND of output signals.