Vertical probe card focusing system
By introducing a focusing probe into the vertical probe card, the problem of inaccurate positioning of the CCD image alignment device is solved, enabling precise alignment of wafer inspection and avoiding the need for a reduction in the size of the probe tip.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-02
- Publication Date
- 2026-03-10
AI Technical Summary
In the existing technology, as the precision of wafer fabrication processes improves, the tip size of the test probe is reduced to less than 10µm, which makes it impossible for the CCD image alignment device to accurately position the image, resulting in abnormal interpretation results.
Design a vertical probe card focusing system, which includes a test probe and a focusing probe. The focusing probe has a tip size greater than 10µm and is used to assist the positioning of the CCD image alignment device. The tip of the test probe does not contact the wafer.
This technology enables the CCD image alignment device to accurately locate the position of the test probe, avoiding the need to reduce the size of the probe tip due to the improvement of wafer manufacturing process precision, and ensuring detection accuracy.
Smart Images
Figure CN223985689U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a probe card used for electrical testing in wafer fabrication processes, and more particularly to a focusing system for a test bench using a vertical probe card. Background Technology
[0002] After wafer fabrication, an electronic testing system is used to test the circuitry within the wafer. This process filters out defective products, reducing the number of defective products in the subsequent packaging process and thus minimizing production cost waste. A probe card is mounted on the wafer testing machine, which serves as the electronic testing system, and acts as the electrical connection between the system and the wafer under test. The probe card has multiple probes that contact the pads or bumps on the wafer to further test the circuitry within it.
[0003] The vertical probe card has a probe holder installed in the middle of the circuit board and multiple downward-extending test probes for contacting the wafer. Before testing the wafer, a CCD (Charged Coupled Device) image alignment device is used to detect the position of the tip of each test probe. Then, based on the detection results, the wafer under test is moved to a predetermined position below the vertical probe card, and then the wafer under test is moved toward the vertical probe card so that the test probes of the vertical probe card contact the corresponding pads or bumps on the wafer under test, so as to further test the circuit in the wafer under test.
[0004] When the aforementioned CCD image alignment device is in operation, it uses an LED (Light Emitting Diode) as a light source to illuminate the tip of the test probe, forming a bright spot on the surface of the tip. The CCD determines the position of each test probe by reading the size of the bright spot on the tip surface. In terms of the current sensing capability of CCDs, in order for the CCD to focus accurately, the diameter of the tip of each test probe must be greater than 10µm (micrometer).
[0005] However, as the precision of wafer fabrication processes continues to improve, the tip size of the test probes used to contact the wafers also needs to be reduced to less than 10µm. This will result in the bright spot size formed on the tip surface of the test probe being too small, causing the CCD to be unable to detect the tip and thus displaying abnormal machine focusing results. Utility Model Content
[0006] In view of the problems existing in the prior art, the purpose of this utility model is to provide a focusing system specifically for vertical probe cards, which can be used to assist in determining the position of probes used to test wafer circuits.
[0007] To achieve the aforementioned objectives, the present invention provides a vertical probe card focusing system, comprising a circuit board and a probe holder, wherein the probe holder is mounted below the circuit board, and multiple test probes and multiple focusing probes are mounted on the probe holder, wherein:
[0008] The test probes are arranged at intervals in the probe holder, and the tips of the test probes protrude from the bottom surface of the probe holder.
[0009] The focusing probes are interspersed among the test probes, and the tip of each focusing probe protrudes from the bottom surface of the probe holder. The length of the tip of each focusing probe protruding from the bottom surface of the probe holder is shorter than the length of the tip of each test probe protruding from the bottom surface of the probe holder.
[0010] In the vertical probe card focusing system, the end face size of the tip of each focusing probe can be larger than the end face size of the tip of each test probe.
[0011] In the vertical probe card focusing system described above, the diameter of the end face of the tip of each focusing probe can be greater than 10µm (micrometer).
[0012] With the design described above, the CCD (Charged Coupled Device) image alignment device can detect the position of the focusing probe and then calculate the position of the surrounding test probes. The focusing probe will not contact the wafer under test during wafer inspection. Therefore, the end face of the tip of the focusing probe can be maintained within the error range of the size that the CCD image alignment device can detect, without shrinking as the precision of the wafer manufacturing process increases. Attached Figure Description
[0013] Figure 1 This is a side view of the present invention.
[0014] Figure 2 This is a side view of the probe holder of this utility model.
[0015] Figure 3 This is a side view of the present invention in use, wherein positioning is performed using a CCD image alignment device.
[0016] Figure 4This is a side view of the present invention in use, in which the wafer to be tested is moved to a predetermined position. Detailed Implementation
[0017] The following, in conjunction with the accompanying drawings and preferred embodiments of the present invention, further illustrates the technical means employed by the present invention to achieve its intended purpose.
[0018] See Figure 1 As shown, the vertical probe card focusing system of this utility model includes a circuit board 10 and a probe holder 20. The circuit board 10 is provided with test circuits for testing the electrical characteristics of the wafer.
[0019] See also Figure 1 and Figure 2 As shown, the probe holder 20 is installed below the circuit board 10, with the two opposite sides of the probe holder 20 being a top surface 201 and a bottom surface 202, respectively. The top surface 201 faces the circuit board 10, and the probe holder 20 is equipped with multiple test probes 21 and multiple focusing probes 22.
[0020] The test probes 21 are arranged at intervals in the probe holder 20. Each test probe 21 is electrically connected to the test circuit provided on the circuit board 10 via an electrode part 30. The tip of the test probe 21 protrudes from the bottom surface 202 of the probe holder 20.
[0021] See also Figure 2 As shown, the focusing probes 21 are interleaved between the test probes 21. The tip of each focusing probe 22 protrudes from the bottom surface 202 of the probe holder 20. The focusing probe 22 is only used for alignment and does not need to be electrically connected to the electrode portion 30 and the circuit board 10. The length D2 of the tip of each focusing probe 22 protruding from the bottom surface 202 of the probe holder 20 is shorter than the length D1 of the tip of each test probe 21 protruding from the bottom surface 202 of the probe holder 20. Therefore, when the test probe 21 contacts the pads or bumps on the wafer under test for wafer inspection, the focusing probe 22 will not contact the pads or bumps on the wafer under test; furthermore, the end face 221 of the tip of each focusing probe 22 is larger than the end face 211 of the tip of each test probe 21. Specifically, the diameter of the end face 221 of the tip of each focusing probe 22 is greater than 10µm (micrometer).
[0022] See further Figure 3As shown, before testing a wafer using the vertical probe card with a focusing system of this invention, a CCD (Charged Coupled Device) image alignment device 40 can be moved to the underside of the vertical probe card. The CCD image alignment device 40 has a CCD 42 and an LED (Light Emitting Diode) 43 on a pair of alignment stages 41. The light emitted by the LED 43 can form a bright spot on the end face 221 of the tip of the focusing probe 22, so that the CCD 42 can detect the position of the focusing probe 22 and thereby calculate the position of the test probe 21 located around the focusing probe 22.
[0023] See further Figure 4 As shown, the CCD image alignment device 40 is then removed, and the test stage 52 with the wafer 51 under test is moved to a predetermined position below the vertical probe card according to the position of the test probe 21 measured above. This ensures that each test probe 21 can be accurately aligned with the corresponding pad or bump on the wafer 51 under test. Then, the vertical probe card can be moved toward the wafer 51 under test, so that the test probe 21 contacts the corresponding pad or bump on the wafer 51 under test, and further tests are performed on the circuitry in the wafer 51 under test.
[0024] The advantage of the vertical probe card focusing system of this utility model is that, since the focusing probe 22 is only used to align the CCD image alignment device 40, it will not come into contact with the wafer under test 51 during wafer inspection. Therefore, the end face 221 of the tip of the focusing probe 22 can be maintained within the dimensional error range that the CCD image alignment device 40 can detect, without shrinking as the precision of the wafer manufacturing process increases. This ensures that the CCD image alignment device 40 can correctly measure the position of the test probes 21 around the focusing probe 22.
[0025] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any simple modifications, equivalent changes and alterations made by any person skilled in the art to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model's technical solution shall still fall within the scope of the present utility model's technical solution.
Claims
1. A vertical probe card focusing system, characterized by, A circuit substrate and a probe socket are included, the probe socket is installed below the circuit substrate, a plurality of test probes and a plurality of focus probes are installed on the probe socket, wherein: The test probes are arranged in the probe socket at intervals, the needle tip of the test probe protrudes out of the bottom surface of the probe socket; The focus probes are arranged between the test probes, the needle tip of each focus probe protrudes out of the bottom surface of the probe socket, the length of the needle tip of each focus probe protruding out of the bottom surface of the probe socket is shorter than the length of the needle tip of each test probe protruding out of the bottom surface of the probe socket.
2. The vertical probe card focus system of claim 1, wherein, The end surface size of the needle tip of each focus probe is greater than the end surface size of the needle tip of each test probe.
3. The vertical probe card focusing system of claim 2, wherein, The diameter of the end surface of the needle tip of each focus probe is greater than 10 µm.