JPH0584669B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is an electrical property test for devices such as transistors or semiconductor integrated circuits fabricated in a semiconductor wafer, and is used to detect defects attached to devices that are rejected. The present invention relates to a method of detecting a passing mark.

BACKGROUND TECHNOLOGY A large number of semiconductor devices fabricated in a semiconductor wafer through a predetermined manufacturing process are individually electrically inspected using a probing device 1' and an electrical characteristic testing device, etc., as shown in the process flow chart shown in FIG. The electrical characteristics are inspected, and a reject mark 3 is placed by the inker 5 on the elements that do not meet certain characteristic conditions.After the electrical characteristics test of a predetermined number of sheets is completed, a reject mark is placed on the elements of appropriate size. A method is adopted in which an operator visually inspects the material using a microscope to see if it has been properly inspected.

In this method, first, a wafer cassette containing a large number of semiconductor wafers is set in the loading station 16 of the probing apparatus 1'. The semiconductor wafers are automatically sent one by one from this wafer cassette to the measurement stage 4.
Here, the electrical characteristics of a large number of semiconductor elements fabricated within the semiconductor wafer are individually tested. An ink mark (dot) is placed on a semiconductor element determined to have failed in this test by an inker 5 to indicate that it is defective.

The semiconductor wafer, on which the electrical characteristics of all the manufactured semiconductor elements have been tested, is sent to the unloader station 17 and stored in a wafer cassette set there. Such inspections proceed one after another, and when a predetermined number of semiconductor wafers have been stored, the wafer cassette is carried by an operator as shown by arrow B to a mark inspection process.

In the mark inspection step 18, the semiconductor wafers are taken out one by one from the wafer cassette, and visually inspected by an operator using a microscope to see if the rejection mark has been placed in an appropriate size. In this mark inspection, the semiconductor wafers on which the size of the rejection mark is properly marked are stored in the wafer cassette again and transported to the next process as shown by arrow C. However, if the size of the rejection mark is If it is determined that the mark size is inappropriate, the operator checks the inker of the probing device that tested the electrical characteristics of the semiconductor wafer, and adjusts the mark size to an appropriate mark size.

Problems to be Solved by the Invention Conventionally, the inspection of rejection marks attached to defective semiconductor devices has been done in batches as described above, which has the disadvantage that the inspection results are slow to be known and the response is delayed. There was an inconvenience that judgments tended to vary depending on each inspector.

Means for Solving the Problems The mark detection method of the present invention uses a photoelectric sensor to automatically detect a rejection mark attached to the surface of a defective semiconductor element. This problem is solved by photoelectrically detecting and automatically determining whether or not the mark has been placed in an appropriate size.

Effect: According to the mark detection method of the present invention, a rejection mark attached to the surface of a defective element among semiconductor elements fabricated in a semiconductor wafer is photoelectrically detected, and the size of the mark is compared with a reference mark size. Since it is judged based on the photoelectric signal level whether or not a mark of an appropriate size has been placed, quick and stable inspection can be performed.

Embodiment The mark detection method of the present invention will be explained with reference to FIGS. 1 to 4.

FIG. 1 is a diagram showing an outline of the work process of mark detection according to this embodiment.

FIG. 2 is a diagram showing the mark detection section, and shows the X-Y
A wafer mounting table 13 for mounting a semiconductor wafer whose electrical characteristics are to be tested is mounted on the table 14, and the X-Y table 14 is driven, and the individual semiconductor elements are sequentially moved to predetermined measurement positions.

The tip of the probe contactor 12 is arranged so as to match the external lead electrode butt provided on each semiconductor element and attached to the probe card board 11, and the other end of the probe contactor 12 is used for testing electrical characteristics. Connected to circuits and measuring instruments.

An inker 5 that marks a semiconductor element with a failure as a result of an electrical characteristic test includes an ink tank 8 having a nozzle 7 having an inner diameter of less than 1 mm at its tip, a needle 9 having a smaller diameter than the hole diameter of the nozzle 7, and It is composed of a solenoid 10 that operates the needle 9 in response to a defective signal from the electrical characteristic tester, and the ink tank 8 contains ink that marks a semiconductor element with defective electrical characteristics as a failure mark. is filled. Red is often used for ink for ease of identification in later processes, and after marking, it is generally heated in a drying oven 19 at approximately 120°C for 30 minutes to dry it and then baked onto the semiconductor wafer. It is true.

The solenoid 10 is activated by a defective signal from the electrical characteristic tester, and the needle 9 attached to the plunger of the solenoid 10 is lowered to deposit ink at a predetermined position on the defective semiconductor element, thereby marking a rejection mark. Attach.

The photoelectric sensor 6 detects a semiconductor element at a distance from the position of the inker 5 that is an integral multiple (n) of the semiconductor element dimension (P) formed in the semiconductor wafer 2 (twice in this embodiment). It is attached to detect the reflected light 15 on the surface, and the inker 5
It is detected whether or not the rejection mark 3 attached by is of an appropriate size.

3A and 3B are diagrams for explaining the method of detecting the size of the rejection mark 3 by the photoelectric sensor 6, A shows a non-defective semiconductor element formed in the semiconductor wafer 2, and the rejection mark by the inker 5 is shown. Since there is no mark attached, the reflectance of the surface is high, and therefore the amount of reflected light becomes maximum as shown in FIG. 3b. B to D indicate semiconductor elements formed in a semiconductor wafer that have poor electrical characteristics and are marked with a rejection mark 3 by the inker 5, and B indicates the size of the rejection mark 3. is the appropriate size, and the amount of reflected light on the surface is small as shown in FIG. 3b.

C indicates that the size of the rejection mark 3 is too large, and the amount of reflected light on the surface of the semiconductor element becomes extremely small as shown in FIG. 3B. Such an excessively large mark may contaminate the surface of an adjacent non-defective semiconductor element due to ink scattering or the like.

2) The size of the rejection mark 3 is too small, and the amount of reflected light becomes very large as shown in FIG.

Such marks that are too small make it difficult to judge the quality of the semiconductor device in the subsequent die mounting operation.

Therefore, the amount of reflected light (output of the photoelectric sensor) in the range from to (the size of the reject mark 3 is too small) and from to to the range from to (the size of the reject mark 3 is too large) in Figure 3b is calculated as follows: A determination device (not shown) connected to the photoelectric sensor 6 performs detection and determination, and determines whether or not the size of the rejection mark 3 is appropriately placed.

FIG. 4 is a diagram illustrating an element in which the electrical characteristics of each semiconductor element formed in the semiconductor wafer 2 and the size of a rejection mark are sequentially inspected.
The electrical property test is carried out sequentially from A-c to E-d and E-e, and a failure mark 3 is placed on the defective semiconductor element using an inker.The electrical property test progresses sequentially to H-c. When the position is moved, the photoelectric sensor 6 for detecting the rejection mark is located on I-c, and the photoelectric sensor 6 is moved in parallel with the electrical characteristic inspection of H-c.
detects the amount of light reflected from the surface of the semiconductor element E-c. For example, since a rejection mark 3a is attached to the surface of the semiconductor element at the position A-c, the amount of reflected light that enters the photoelectric sensor 6 is reduced, and the output of the photoelectric sensor 6 becomes small.

When the electrical characteristic test is located at H-e, the photoelectric sensor 6 detects the semiconductor element E and a reject mark 3b is attached, so the amount of reflected light is reduced, but the size of the reject mark 3b is too large. Therefore, the amount of reflected light that enters the photoelectric sensor 6 becomes minimal, and the output of the photoelectric sensor 6 also becomes minimal.

When the electrical characteristic test is at Need-d, the photoelectric sensor 6 detects the amount of reflected light of Low-d, but since the rejection mark 3c is too small, the output of the photoelectric sensor 6 becomes rather large.

In this way, by inspecting the electrical characteristics of each semiconductor element formed within a semiconductor wafer and simultaneously detecting the difference in the amount of light reflected from the surface of each semiconductor element that enters the photoelectric sensor, defective semiconductor elements can be detected. The size of the rejection marks placed on the semiconductor wafer is sequentially inspected, and when a predetermined number of improperly sized marks are found on one semiconductor wafer, the probe inspection is stopped, an alarm is issued, and the operator is notified. .

Effects of the Invention As described above, in the mark detection method of the present invention, a rejection mark attached to a defective semiconductor element is detected by a photoelectric sensor in parallel with the electrical characteristic inspection of each semiconductor element formed in a semiconductor wafer. Because it detects markings, there is no need for a worker to inspect marks as in the past, which improves work efficiency and improves work efficiency.
This has the effect of allowing the size of the rejection mark to be quickly determined after marking.

[Brief explanation of the drawing]

Fig. 1 is a process flow diagram outlining the working process of the mark detection method of the present invention, Fig. 2 is a side view of the apparatus showing the mark detection section, and Fig. 3 is a state showing the method for detecting the size of a reject mark. FIG. 4 is a plan state diagram showing the process of detecting a reject mark, and FIG. 5 is a process flow chart showing an outline of the process of a conventional mark detection method. 1...Probing device, 4...Measurement stage, 5
...Inker, 6...Photoelectric sensor.

Claims (1)

[Claims] 1 A probing device sequentially inspects the electrical characteristics of a large number of semiconductor elements fabricated on a semiconductor wafer, and an inker marks the semiconductor elements determined to be defective with a rejection mark. A wafer mark detection method characterized in that the rejection mark is detected by a photoelectric sensor at a position separated from the inker. 2. The X direction is an integer multiple of the X direction dimension of the one semiconductor element, and the Y direction is the Y direction possible dimension of the one semiconductor element from the rejection mark formation position where the rejection mark is detected by the inker. 2. The wafer mark detection method according to claim 1, wherein the detection is performed using a photoelectric sensor at positions spaced apart by an integral multiple of .