JPS6399541A - Semiconductor wafer prober apparatus - Google Patents

Abstract

PURPOSE:To establish a highly reliable prober inspecting process, by providing a means for picking up the image of a wafer, in which ink is attached on defective products, with a TV camera, and providing a means, which compares the measured value with a standard wafer value, judges good products when the values agree with each other and counts the results. CONSTITUTION:A wafer 5, whose electric performances have been measured, is accurately positioned and mounted on a measuring stage 4. Light from a light source is converged through a convergent lens 8 in a TV camera 3, which is provided so as to face the wafer. The light is projected on the wafer 5 and the image of the reflected light is picked up with the ITV camera. The image is converted into an electric signal, and the image output is stored in a memory. The stored image data of the wafer 5 to be measured are compared with the image data, which are taken out of a chip that is not marked before the measurement and are not memorized beforehand. When the image data of the wafer to be measured do not agree with the reference data, a chip corresponding to the disagreed place, i.e., the inked chip, also disagrees. Therefore the chip is judged to be the inked chip 1a. The agreed chip is judged to be a chip without ink 1b. Then the results are counted. Thus the highly reliable wafer inspection can be carried out.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) This invention relates to a semiconductor wafer prober device (prior art) A prober device such as a semiconductor wafer prober is disclosed in Japanese Patent Laid-Open No.
This method is well known from Japanese Patent No. 9-35441, and various electrical performances are measured by bringing a semiconductor chip formed on a semiconductor wafer placed on a measurement stage into contact with a probe card, and defective chips are inked with a marker such as an inker. This marks the chip as defective. Normally, a tester or prober device has a function to count the number of non-defective chips based on the test results, but if an inking error causes ink to splatter on a chip that has been determined to be non-defective in the test result, or ink adheres to the chip, or the ink In some cases, due to a mistake, ink may not be applied to chips with defective inspection results. To prevent such mistakes, after the wafer measurement is completed, the operator uses a magnifying glass to view the chips, counts the number of chips that have not been inked using a manual counter, and checks the test results with the tester or prober device. The team was working to find malfunctions in marking devices such as inkers by comparing the number of good chips based on the number of chips.

(Problem to be Solved by the Invention) As mentioned above, counting chips with no ink attached relies on the eyes of experts who have acquired the detection ability after a long period of practice. There was a request to automate the counting of chips that have not been done yet.

This invention was made to solve the above points,
By making the counting of chips without ink adhering an automatic process, it is possible to shorten the time it takes to discover marker malfunctions, improve reliability, and reduce the number of chips between processes without conveying the incorrect number of non-defective products to subsequent processes. The present invention provides a semiconductor wafer prober device that eliminates unnecessary troubles.

[Structure of the invention]

(Means for Solving the Problem) The present invention provides a means for imaging a wafer with ink attached to a defective product based on inspection results of a large number of regularly formed chips, and a means for imaging a wafer with ink attached to a defective product based on inspection results of a large number of regularly formed chips, and A semiconductor wafer prober device is provided, comprising means for comparing the standard wafer values stored in memory, and determining that the wafer is non-defective when they match, and then force-pounding the wafer.

(Function) A means of imaging a wafer with ink attached to a defective product based on the inspection results of a large number of regularly formed chips with a TV camera, and comparing the output of the TV camera and the standard wafer value stored in advance. By providing a means for determining and counting a non-defective product when the results match, it is possible to significantly shorten the counting time when no ink is attached, leading to the establishment of a highly reliable prober inspection process.

(Embodiment) Next, an embodiment of the semiconductor wafer prober device of the present invention will be described with reference to the drawings. The feature of this embodiment is that a defective semiconductor chip (1a) was found by inspection using a wafer prober.
), and the wafer with the ink (2b) that was scattered due to an inking mistake, is imaged with an ITV camera ■, and the number of chips (1b) to which no ink is attached is counted. be.

The wafer prober carries the wafer cassette containing wafers into the cassette storage section, takes out the wafers one by one from the storage section, and transports them onto the measurement stage (a). After the transported wafer 0 is aligned with the orientation flat or the like as a reference, the measurement stage automatically soft lands on the probe card from below, and the inspection is automatically started. The measurement is configured to measure the electrical performance of a large number of chips formed on wafer 0, and to perform an inking operation in which defective products are coated with ink (■) using a marker (for example, an inker (0). After the measurement is completed, the probe The card is moved away from above the wafer, and a TV camera is set above the wafer for the good product counting process.In order to execute these automatic processes, it is necessary to perform a teaching operation prior to the continuous process. This operation is performed by the operator while checking the pad position of wafer 0 using the TV camera (3).

Accurately position and place the wafer 0 whose electrical performance has been measured on the measurement stage (a), and place the TV camera (3
) The light from the light source installed next to the converging lens (8
) to irradiate the wafer 0, the reflected light is imaged by a TV camera, for example, an ITV camera, and converted into an electrical signal (Figure 1 (A)) The image output is stored in a memory (Figure 1 (B) ). Image information of the memorized wafer to be measured ■ and pre-memorized image information (reference data) taken with an unmarked chip before measurement (Fig. 1)
C)) (Figure 1 (D)). This comparison compares the chips that are being formed on the wafer (C) one by one, and all chips are compared, and the points where the compared reference data and the image data of the wafer under test do not match (
The chip corresponding to FIG.
), and the chip that matches (Fig. 1 (F)) is determined to be a chip with no ink (1b) and is counted (
Figure 1 (G)). The counted number of chips (1b) to which no ink is attached is displayed on a display (1o) installed in the prober. Of course, chips that match the reference data are determined and displayed as chips without marks. At this time, based on the inspection results during the measurement, a wafer map created in the storage memory inside the prober device stores which chips are found to be good and which chips are defective. If the maps of the chip with the mark (usually the inspection result is defective) and the chip without the mark (the inspection result is normally good) recognized by this wafer map and the ITV camera are the same, there was no marking error. Since this can be determined, highly reliable wafer inspection becomes possible by eliminating the need for operators to count unmarked chips and collate the number of chips with good inspection results. In the above embodiment, an example was explained in which the number of chips without ink is counted. However, if ink is scattered during inking work on defective chips and ink adheres to good chips, the number of chips that are not marked with ink may be counted. By storing the characteristics of the pattern in memory in advance, it is possible to select and judge the corresponding chips that have been adhered to by the scattered ink.In other words, it is possible to selectively judge chips that have been determined to be good by inspection but have ink adhering to them and have marks. It can be fixed.

This accuracy can be automated and brought close to the operator's accuracy by storing all ink patterns for which the operator has corrected and determined that the scattered ink is good quality as pseudo ink patterns in the reference data. Area is also a big factor in the difference between scattered ink and normal mark ink.
The predetermined shape is also a major factor, and having the density is also a major factor. A mark of normality is generally one in which the above elements are relatively consistent. This can be easily determined by pattern recognition.

Further, in the above embodiment, chips to which ink is not adhered are counted, but it is also possible to count chips to which ink is adhered. However, ink is also applied to chips at the edge of the wafer that are not completely configured as circuits, and the configuration of the chips at the edge differs from wafer to wafer, so the number of chips at the edge with ink is Since each wafer is different, counting the number of chips with ink attached will not be very effective.

〔Effect of the invention〕

As described above, according to the present invention, by automating the operation of detecting and counting the presence of marks on chips formed on a wafer, it is possible to shorten the time required to count non-defective products, and the reliability is comparable to that of a wafer prober. It has the effect of leading to improvement.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a block diagram for explaining one embodiment of the present invention, FIG. 2 is a diagram of a wafer on which the chips of FIG. 1 are formed, and FIG. 3 is a diagram of the wafer shown in FIG. 1. FIG. 2 is a diagram of a wafer prober. la Defective chip 1b Chip with no ink attached 2...Ink 3...TV camera 5...Wafer
6... Inker 8... Lens

Claims (2)

[Claims] (1) A means of imaging a wafer with ink attached to a defective product based on the inspection results of a large number of regularly formed chips with a TV camera, and comparing the output of the TV camera and the standard wafer value stored in advance. 1. A semiconductor wafer prober device, comprising: means for determining and counting a non-defective product if they match. (2) The semiconductor wafer prober device according to claim 1, wherein the chips to which ink has been applied include chips to which ink has been erroneously adhered.