A probe station needle mark detection method

Abstract

The present invention relates to the field of semiconductor technology. Specifically, a probe station needle mark detection method is provided, which enables wafer movement, image processing, and data storage of the probe station to be performed simultaneously by establishing a motion thread and an image thread to work in parallel. The needle mark detection method provided by the present invention can monitor the stability of test accuracy during wafer testing to ensure the test yield, and can also monitor the use of the needle card, whether there is any needle abnormality, etc.; and adopts a dual-thread mode to perform motion and image data processing simultaneously, greatly improving the detection efficiency.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to a method for detecting needle marks on a probe station. Background Art

[0002] The traditional method for detecting needle marks is to first move to the position of the first image to be detected, perform image data processing on all chip solder joints (pads) in the current image and give the result, and then continue to perform image data processing after the next movement. When using this method of alternating movement and image processing, when the number of pads to be inspected is very large, the detection is very time-consuming, the efficiency is low, and a large amount of test time will be occupied. Summary of the Invention

[0003] In view of the above problems, the present invention proposes a method for detecting needle marks on a probe station, which adopts a dual-thread mode to simultaneously perform movement and image data processing, greatly improving the detection efficiency.

[0004] The present invention provides a method for detecting needle marks on a probe station, which enables the wafer movement, image processing, and data storage of the probe station to be carried out simultaneously by establishing a movement thread and an image thread to work in parallel.

[0005] Preferably, the needle mark detection steps include:

[0006] S1: Calculate the number of detection regions n according to the die size and the camera field of view size;

[0007] S2: Calculate the coordinates (X i , Y i ) of each detection region according to the coordinates of the current die and the number of regions n;

[0008] S3: Start the movement thread and the image thread to work simultaneously.

[0009] Preferably, the movement thread moves the platform carrying the wafer to the specified position.

[0010] Preferably, when the movement thread detects the point (X i , Y i ), it immediately runs the program of whether i is greater than n:

[0011] When i < n, continue to execute i = i + 1 to make the movement thread move to the point (X i+1 , Y i+1 );

[0012] When i > n, the movement thread ends its work.

[0013] Preferably, the movement thread moves the region to be detected under the camera, and the movement time for each time is t mi (i = 0, 1,..., n).

[0014] Preferably, the image thread detects images through a camera, obtains and saves needle mark detection data of chip solder joints on the wafer to be tested.

[0015] Preferably, the processing time of each image thread is: t ci (i=0, 1,…, n).

[0016] Preferably, the time for the motion thread and the image thread to work simultaneously is: max(∑t mi ,∑t ci ), (i=0, 1,…, n).

[0017] The present invention can achieve the following beneficial effects:

[0018] (1) The multi-threaded probe mark detection method proposed in this paper adopts the parallel method of motion and image processing to improve the detection efficiency. Especially when the number of pads to be inspected is very large, it can greatly shorten the probe mark detection time and improve the test efficiency.

[0019] (2) This method can also be applied to other functions of the probe station to shorten the probe station test time and improve the probe station test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a detection procedure diagram of a probe station needle mark detection method of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0022] A probe station needle mark detection method provided by the present invention will be described in detail below with reference to embodiments.

[0023] The invention provides a probe station needle mark detection method, which enables wafer movement, image processing and data storage of the probe station to be performed simultaneously by establishing a motion thread and an image thread to work in parallel.

[0024] In one embodiment of the present invention, when performing probe station needle mark detection, two threads are established, the first thread is responsible for moving the carrier platform, and the second thread is responsible for image processing. The two threads are started at the same time. When the motion thread captures the first image, the image thread simultaneously performs processing of the acquired image; while the image thread is processing, the motion thread performs a second image capture, and so on, implementing parallel work of the two threads.

[0025] Figure 1It is a program diagram of a method for detecting needle marks on a probe station according to the present invention.

[0026] As Figure 1 shown, the needle mark detection steps include:

[0027] S1: Calculate the number of detection areas n according to the die size and the camera field of view size;

[0028] S2: Calculate the coordinates (X i , Y i ) of each detection area according to the coordinates of the current die and the number of areas n;

[0029] S3: Start two threads to work simultaneously.

[0030] Before starting the threads, calculate the number of detection areas n according to the die size and the camera field of view size; then calculate the coordinates of each detection area according to the coordinates of the current die and the number of areas n, and then start the motion thread and the image processing thread.

[0031] In an embodiment of the present invention, calculate the number of detection areas n according to the die size and the camera field of view size. The calculation method is as follows: Assume that the camera field of view size is 0.6mm × 0.6mm. To avoid the pads to be recognized moving to the edge of the field of view and affecting the recognition, the effective field of view size is set to 0.5mm × 0.5mm; the size of a die is 4mm × 4mm, then the number of detection areas required to recognize all the pads in the die is 64; if there are no pads to be detected in this area, this area will be deleted.

[0032] In the present invention, die refers to a chip, and pad refers to a solder joint on the chip.

[0033] The motion thread moves sequentially according to the coordinates of each calculated detection area, and the image thread also performs image processing sequentially according to the images captured by the motion thread.

[0034] In an embodiment of the present invention, the motion thread is only responsible for moving the platform carrying the wafer and moving each detection area under the camera. When the motion thread detects the point (X i , Y i ), it immediately runs the program of whether i is greater than n:

[0035] When i < n, continue to execute i = i + 1 to make the motion thread move to the point (X i+1 , Y i+1 );

[0036] When i > n, the motion thread ends its work. The time of each movement is recorded as t mi(i=0, 1, ..., n); After each detection area moves under the camera, in the image processing thread, the image of the current detection area is obtained through the camera, and then processed to obtain and save the needle mark detection data of all pads in the current detection area. The image processing time for each time is recorded as t ci (i=0,1,…,n), since the two threads in the present invention work simultaneously, the working time is reduced from the original ∑t mi +∑t ci becomes max(∑t mi ,∑t ci )(i=0,1,…,n), which greatly shortens the detection time.

[0037] The probe station needle mark detection method provided by the present invention can monitor the test accuracy stability during the wafer test process to ensure the test yield, and can also monitor the use of the needle card to see if there are any needle abnormalities. In addition, the dual-thread mode is adopted to perform motion and image data processing at the same time, which greatly improves the detection efficiency.

[0038] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0039] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

[0040] The above specific implementations of the present invention do not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A probe station needle mark detection method, characterized in that: By establishing motion threads and image threads to work in parallel, the wafer movement, image processing, and data storage of the probe station can be performed simultaneously; The needle mark detection method comprises: S1: Calculate the number of detection areas n based on the die size and camera field of view size; S2: Calculate the coordinates of each detection area (X i , Y i ); S3: Start the motion thread and the image thread to work simultaneously; the motion thread moves the wafer-carrying platform to move the wafer to the specified position; the image thread detects the image through the camera, obtains the needle mark detection data of the chip solder joints on all the wafers to be tested and saves it; when the motion thread captures the first image, the image thread simultaneously processes the acquired image, and while the image thread is processing, the motion thread captures the second image, and so on, the two threads work in parallel; the motion thread moves the area to be tested under the camera, and the movement time of each time is t mi (i=0, 1, ..., n), the processing time of each image thread is: t ci (i=0, 1, ..., n), the time for the motion thread and the image thread to work simultaneously is: max(∑t mi ,∑t ci ), (i=0, 1,…, n).

2. The probe station needle mark detection method according to claim 1, characterized in that: The motion thread detects (X i , Y i ) point, then immediately run the program to see if i is greater than n: When i < n, continue to execute i = i + 1 to move the motion thread to the point (X i+1 , Y i+1 ); When i>n, the motion thread finishes its work.

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