Method for aligning gap wafer by aiming at probe station

Abstract

The invention belongs to the technical field of semiconductor manufacturing and testing, particularly relates to a method for testing a notch wafer for a probe station, and aims to solve the problems that when an additional notch or edge breakage exists at the edge of the wafer, a sensor may mistakenly recognize that two or more Notch ports exist, so that equipment cannot determine the correct crystal orientation, and the wafer cannot be detected. A high-density shading device is used for shading a notch in the edge of a wafer, so that a sensor cannot detect an abnormal outline, equipment is ensured to only identify a real Notch port, and smooth execution of full-automatic testing is realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor manufacturing and testing, and particularly relates to a method for testing a wafer with a notch by a probe station. BACKGROUND

[0002] In the process of manufacturing a 12-inch wafer, due to the complexity of the previous process and the large number of process steps, the edge of the wafer is prone to physical damage such as edge collapse and notch. Such damage will cause the equipment alignment system to misidentify multiple Notch openings (a small V-shaped or U-shaped notch on the edge of the wafer) during the subsequent testing process, especially when using a UF3000 probe station for automatic testing, thereby triggering an alignment alarm and interrupting the testing process, which seriously affects the production efficiency and yield.

[0003] The alignment principle of the UF3000 probe station is as follows: the sensor detects the profile of the wafer edge and the position of the Notch opening (or flat edge), calculates the center of the wafer and the crystal direction, and when there is an additional notch or edge collapse on the wafer edge, the sensor may misidentify the presence of two or more Notch openings, causing the equipment to be unable to determine the correct crystal direction, triggering an alarm and stopping the test.

[0004] Currently, common methods for dealing with such problems include manual intervention, equipment parameter adjustment, or wafer scrapping, which not only have low efficiency, but also increase production costs and time loss. Therefore, there is an urgent need for a simple, reliable and non-invasive method for the normal automatic testing of notched wafers. SUMMARY

[0005] To solve the above technical problems, the present application provides a method for aligning a notched wafer by a probe station.

[0006] A method for aligning a notched wafer by a probe station, comprising the following steps: S1, checking the edge of the wafer to identify abnormal notches; S2, selecting a high-density light-shielding device, precisely fitting it to the surface of the notch after adapting to the shape and size of the notch, ensuring complete coverage of the notch area and not blocking the effective chip area and the real Notch opening; S3, sending the processed wafer into the probe station for edge scanning and Notch positioning; S4, the sensor can only identify the Notch opening that is not blocked, thereby correctly calculating the center of the wafer and the crystal direction, completing automatic alignment and performing testing.

[0007] Technical effects: The present application uses high-density light shielding device to shield the wafer edge notch, so that the sensor cannot detect abnormal profile, thereby ensuring that the equipment only identifies the real Notch port, and realizing the smooth execution of full-automatic test. The UF3000 probe station alignment failure problem caused by wafer edge collapse and notch is effectively solved; the operation is simple and fast, and the equipment hardware or software parameters do not need to be modified; the position is flexible, does not occupy the effective area of the chip, and does not affect the electrical test; the automatic test efficiency is greatly improved, the wafer scrap and production interruption time are reduced; it is suitable for mass production environment, and has good popularization and economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 It is a schematic diagram of the whole implementation process of the present application. DETAILED DESCRIPTION

[0009] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application.

[0010] The present embodiment proposes a method for probe station alignment of a wafer with a notch, comprising the following steps: The robot takes the wafer out of the transfer box and places it on a rotating platform with an edge sensor and a Notch port sensor, checks the wafer edge, and identifies the abnormal notch formed due to edge collapse or damage; A high-density light shielding device is selected, which is precisely fitted on the notch surface after being adapted to the shape and size of the notch, to ensure that the notch area is completely covered and the effective chip area and the real Notch port are not blocked; The processed wafer is sent to the probe station by the robot, and when the platform rotates, the edge sensor emits a light beam and receives the reflected signal to perform edge scanning and Notch positioning; Since the notch is covered by the light shielding tape, the light beam cannot penetrate or produce abnormal reflection, and the sensor can only identify the Notch port that is not blocked, so as to correctly calculate the wafer center and crystal direction, complete automatic alignment and perform test.

[0011] Further, the high-density light shielding device is a high-density light shielding tape (such as black opaque polyester tape) cut into an appropriate shape and closely fitted on the notch to ensure that the edges of the tape are flatly fitted on the wafer surface without bubbles or lifting.

[0012] Further, the high-density light shielding device is a solidifiable light shielding coating, which uses a light-curable or heat-curable light shielding material (such as UV-curable ink or heat-curable light shielding glue) to coat the notch, and forms a firm opaque layer after curing.

[0013] All aspects of this invention not described in detail herein are well-known to those skilled in the art. The above description only illustrates certain exemplary embodiments of the invention. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of this invention.

Claims

1. A method for aligning a probe station with a notched wafer, characterized in that, Includes the following steps: S1. Inspect the wafer edges to identify abnormal gaps; S2. A high-density light-shielding device is selected and precisely fitted to the surface of the notch after being adapted to the shape and size of the notch, ensuring complete coverage of the notch area without obstructing the effective chip area and the real Notch port. S3. Send the processed wafer into the probe station for edge scanning and Notch positioning; S4. The sensor can only identify unobstructed notch ports, thereby correctly calculating the wafer center and crystal orientation, completing automatic alignment and performing tests.

2. The method for aligning a probe station with a notched wafer according to claim 1, characterized in that, The high-density light-shielding device is a high-density light-shielding tape, which is cut into an appropriate shape and tightly fitted to the notch to ensure that the edge of the tape is flat and fitted to the wafer surface without bubbles or lifting.

3. The method for aligning a probe station with a notched wafer according to claim 1, characterized in that, The high-density light-shielding device is a curable light-shielding coating. The notch is coated with a light-curing or heat-curing light-shielding material, and after curing, it forms a strong opaque layer.

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