JPH01101644A - Detection of prober waveform - Google Patents

Abstract

PURPOSE:To improve the reliability of a probe test by investigating an input waveform by bringing a predetermined probe into contact with an electrode of a particular shape pattern provided on a wafer stage side or a wafer stage and then applying an input signal to the probe. CONSTITUTION:An electrode of a particular shape pattern, for example, a cross shaped pattern 11 is provided on a wafer stage 8 side or a wafer stage 8. A predetermined probe 6 is brought into contact with the electrode and supplied with an input signal, for investigation of a signal waveform. In other words, the electrode of the particular shape pattern with which the one probe 6 among many probes 6 can make contact is provided, with which the predetermined probe is brought into contact, for investigation of the signal waveform. Hereby, it is possible to check on any abnormal signal waveform which might occur on the whole signal transmission path up to the top probe, thereby improving the reliability of the test.

Description

[Detailed Description of the Invention] [Summary] Regarding the improvement of the prober waveform detection method, the purpose is to check the deformation of the signal waveform that occurs in the signal transmission path up to the probe at the tip. The device is characterized in that an electrode having a special-shaped pattern (for example, a cross-shaped pattern) is provided on the top, a predetermined probe is brought into contact with the electrode, and an input signal is applied to the probe to examine the input waveform.

[Industrial application field] The present invention relates to an improved waveform detection method for a prober.

Conventionally, in semiconductor devices such as ICs, a large number of elements are provided on a semiconductor wafer, and before dividing this into individual chips, a probe is brought into contact with the semiconductor wafer.
The quality of the electrical characteristics of these elements is determined, and this is called a wafer probe test.

This is because if a probe test is performed in advance on a wafer, the man-hours for assembling a defective chip into a package and the materials used for the package can be saved.After such a probe test, semiconductor device products are almost 100% reliable. Yields close to . It is desired that such a wafer probe test, that is, a wafer test, be as reliable as possible.

[Problems to be solved by the prior art and the invention] Figure 4 shows a cross-sectional outline of the probe/test head of a prober (probe test device), where 1 is a test driver, 2 is
is a performance port.

3 is a contact ring, 4 is an insert ring.

5 is a probe card, 6 is a probe, 7 is a wafer, 8
9 is a wafer stage, and 9 is a prober body. Of these, the wafer stage 8 has the function of vacuum chuffing and holding the wafer 7 and being movable in both the X and 7 directions. In addition, a specific probe card 5 is created for each type of probe card, and the number of probes installed on the card may be as small as that for civil engineering, or as many as 100 or more. The spacing (equal to the spacing between electrode pads on the wafer) is on the order of several hundred μm. At the beginning of the test, probe 6 was applied to wafer 7.
When aligning the electrode bands, the wafer stage 8 is observed using a microscope through the viewing window 10 in the center, and the wafer stage 8 is moved using a manual function to align it to the required electrode band.

However, in order to maintain the reliability of probe tests, it is necessary to check (detect) whether the probes (not shown) including the test head are operating correctly and whether normal test signals are being applied to the wafer. Therefore, the prober is checked regularly. The conventional detection method involves bringing a stylus P into contact with the performance pad 2 (see FIG. 4), and examining the input signal waveform by projecting it on an oscilloscope or the like. For example, the input signal waveforms are shown in Figures 5(a) to (C). Figure 5(a) is a normal waveform, and the upper part of the figure is a defective noise-superimposed waveform with noise. Figure (C) shows a defective delay waveform with a time lag, and there are other defective waveforms such as distorted waveforms. When these defective waveforms are observed, the signal transmission path from performance port 2 to probe 6 Adjustments or repairs have been made.

The reason why this conventional method uses a stylus in contact with the performance port for detection is that the structure from the performance port to the probe at the tip is minute and complex.
This is because it is extremely difficult to make contact with the oscilloscope's stylus.

However, with this method, it is possible to check the signal waveform of the circuit section that runs from the calculation control unit (not shown) that drives the test driver, passes through the test driver, and goes to the performance port, but the It is not possible to check for abnormalities in the applied waveform that occur during this time. This causes a decrease in the reliability of the probe test.

The present invention solves these problems and proposes a prober waveform detection method aimed at checking the deformation of the applied waveform that occurs in the signal transmission path up to the probe.

[Means for solving the problem] The purpose is to provide an electrode having a special shaped pattern (for example, a cross-shaped pattern) on the side of the wafer stage or on the wafer stage, and to contact the electrode with a predetermined probe. This is achieved by a prober waveform detection method that applies an input signal to the probe and examines the signal waveform.

[Operation] That is, in the present invention, an electrode having a special pattern that can be contacted by only one probe out of a large number of probes is provided, and a predetermined probe is brought into contact with the electrode to examine the signal waveform.

This allows you to check for abnormalities in the signal waveform that occur along the entire signal transmission path up to the probe at the tip.
Improves test reliability.

[Example] Hereinafter, embodiments will be described in detail with reference to the drawings.

1(a) and 1(b) are block diagrams of the waveform detection method according to the present invention, FIG. 1(a) is a cross-sectional schematic diagram, and FIG. The same parts are given the same symbols, except that 11 is a cross-shaped pattern, 12 is a pattern stage, and 13 is a derivation line. The cross-shaped pattern 11 has a shape that can be contacted by only one probe, and is arranged on the pattern stage 12 and positioned at the same height as the wafer 7 in order to make good contact with the probe. The pattern stage 12 is configured to move integrally with the wafer stage 8. Further, the lead wire 13 is covered with a shield wire to avoid the influence of noise, and is led out to the outside of the blow-type body 9 and connected to an oscilloscope (not shown). .

Then, the wafer stage 8 and pattern stage 12 are manually moved while observing with a microscope through the viewing window 10, and a predetermined probe is aligned and brought into contact with the cross-shaped pattern.Next, the signal waveform is input and the signal waveform is input. Check the shape.

Figures 2 (a) to (d) show a state in which a specified probe is in contact with a cross-shaped pattern, and when the distance between the probes is 500 μm, the line width of the cross is about 300 μm, and the cross pattern is Use lines vertically, horizontally, and horizontally. FIG. 2 shows the view seen through the viewing window 10 with a microscope. FIG. 2(a) shows the probe in contact with the lower probe, FIG. C) is a diagram in which the probe is in contact with the left probe, and (d) is a diagram in which it is in contact with the right probe, with 6' being the contact probe.

The next figure 3 is a plan view of the wafer stage part in another arrangement example, in which a cross-shaped pattern 11 is arranged on the wafer stage 8, and this cross-shaped pattern 11 is fixed and does not touch the wafer surface. Check the signal waveform in the same way as above with the pattern surface located at the same height.
It is possible.

Note that such a pattern 11 can be created, for example, by applying insulating photoresist to the conductor surface, opening a window in the shape of a cross using a photo process, and then plating with gold to bury the cross-shaped portion to flatten the surface. Create with.

Further, this pattern is not limited to a cross shape, and other shapes such as a cross star pattern may be created and used.

According to the waveform detection method as described above, it is possible to check the signal waveform that has passed through all the signal transmission paths, and the probe test can be made highly reliable.

[Effects of the Invention] As is clear from the above description, according to the present invention, the signal waveform input from the prober to the wafer is sufficiently checked, the reliability of the probe test is improved, and the quality of the IC is improved by two yields. This contributes to improvement.

[Brief explanation of the drawing]

1(a) and 1(b) are block diagrams of the waveform detection method according to the present invention, FIG. 2 is a diagram showing the contact state of the cross-shaped pattern, and FIG.
The figure is a plan view of a wafer stage portion in another arrangement example, FIG. 4 is a diagram showing a cross-sectional outline of a probe test head, and FIGS. 5(a) to (C) are diagrams showing input waveforms. In the figure, 1 is a test driver, 2 is a performance port, 3 is a contact ring, 4 is an insert ring, 5 is a probe card, 6 is a probe, 7 is a wafer,
8 is a wafer stage, 9 is a prober body, 1
0 is a viewing window, 11 is a cross-shaped pattern, 12 is a pattern stage, and 13 is a derived line palm shape C'7'
-> I11 construction ＾ fire started ° ε ne 70 Fig. 2

Claims (2)

[Claims] (1) An electrode with a specially shaped pattern is provided on the side of the wafer stage or on the wafer stage, a predetermined probe is brought into contact with the electrode, and an input signal is applied to the probe to examine the input waveform. Prober waveform detection method. (2) The prober waveform detection method according to claim 1, wherein the special-shaped pattern is a cross-shaped pattern.