Probe replacement method of cantilever probe card

Abstract

The invention belongs to the technical field of MEMS cantilever probe cards, and particularly relates to a probe replacement method of a cantilever probe card. The method comprises the steps that a clamping jaw clamps a probe body from the back of a probe, heating laser irradiates the clamping position of the clamping jaw from the upper portion of the clamping jaw to the inclined lower portion, laser spots are located in the area where the two clamping jaws are located, and soldering tin is preset on the welding face of a normal probe body used for replacement. The technical scheme provided by the invention has the following technical advantages: 1) the split type clamping jaw is adopted, so that the processing difficulty and cost are reduced; (2) the heating position of a laser spot is changed, the problem of thermal deformation of a probe arm is avoided, the position of a clamping jaw is matched with the laser spot, and the influence of laser on an adjacent probe is shielded to the maximum extent; and (3) the tin-containing probes are used for welding, so that the problems that tin cannot be supplemented due to the small distance between the adjacent probes after the probes are desoldered, and the tin amount is insufficient when the probes are planted are solved, the welding spot strength is improved, and the welding strength and the electrical stability of the maintenance position are improved.

Description

Technical Field

[0001] This invention belongs to the field of MEMS cantilever probe card technology, specifically relating to a probe replacement method for a cantilever probe card. Background Technology

[0002] MEMS cantilever probe cards (hereinafter referred to as probe cards) are core components of semiconductor chip testing. Their main function is to establish an electrical connection between the chip and the testing equipment during the wafer testing stage of chip manufacturing, so as to achieve accurate detection of the chip's electrical performance and function, screen out qualified chips, and reduce subsequent packaging costs.

[0003] A single probe card often uses 30,000 to 100,000 probes. Damage to any one probe can render the entire probe card unusable, resulting in huge losses. Therefore, there is an urgent need for stable and efficient probe repair methods to reduce the scrap rate of probe cards and improve the manufacturing yield and service life of probe cards.

[0004] Currently, when a probe in the probe card is damaged, the replacement procedure is as follows: the clamp holds the damaged probe, desolders it, and then removes it from the substrate. Next, the clamp holds the normal probe to be replaced and moves it to the pad position for soldering. Finally, the clamp is removed to complete the replacement.

[0005] Chinese patent CN221658475U discloses a gripper for MEMS probe welding, which is used for probe welding during the production process, such as... Figure 1 As shown, a cantilever probe generally includes a probe body 11 for soldering pads and support, a probe tip 12 facing the wafer side, and a cantilever 13 connecting the probe body 11 and the probe tip 12. During production, the grippers hold the probe body 11 from top to bottom, and the laser can heat the probe from the side in the horizontal direction. However, this method is not suitable for maintenance conditions where probes are present on both sides, as explained below.

[0006] The probe cards that have already been manufactured have a probe-to-probe gap of <100µm. During desoldering and resoldering, the clamps used in the probe card manufacturing process are employed. Due to space constraints, interference with adjacent probes occurs. Therefore, the clamp thickness needs to be adjusted to allow for smooth insertion between probes. To ensure stable clamping from top to bottom, the clamping depth needs to be increased, reaching at least half the probe height. Furthermore, due to the presence of adjacent probes, current technology uses lasers to vertically irradiate the probe cantilever from top to bottom, melting the solder paste through probe heat conduction. This results in significant thermal damage to the probe arms, and the laser spot also radiates to adjacent probes, causing unnecessary damage. Finally, due to the limited space, desoldered probes cannot be re-soldered, leading to insufficient solder strength in resoldered probes. Summary of the Invention

[0007] This invention provides a probe replacement method for a cantilever probe card to solve the above-mentioned technical problems.

[0008] To solve the above-mentioned technical problems, the present invention provides a probe replacement method for a cantilever probe card, which includes grippers holding the probe body from behind the probe, and a heating laser irradiating the gripper holding position from above the grippers at an angle downward. The laser spot is located in the area where the two grippers are located, and the welding surface of the normal probe body to be replaced is pre-soldered with solder.

[0009] The gripper holds the needle body from behind, and the laser irradiates the same area. In this way, the laser is blocked by the gripper and will not affect adjacent probes. The lower rear of the needle body is closer to the solder. Therefore, compared with the existing technology of irradiating the cantilever, directly irradiating the lower rear of the needle body from the upper oblique angle has a higher heat transfer efficiency and will not cause thermal damage to the needle arm.

[0010] Optionally, the angle between the laser projection angle and the horizontal plane is 20° to 80°.

[0011] Optionally, the gripper includes a left side portion and a right side portion that can move towards each other. The left side portion includes a left gripper arm and a left gripping part detachably connected to the left gripper arm. The right side portion includes a right gripper arm and a right gripping part detachably connected to the right gripper arm.

[0012] In order to be successfully inserted into the gap between the probes, the thickness of the top of the clamping part needs to be very thin, which makes it easy to be damaged and deformed. Even a small amount of damage or deformation can directly lead to insufficient clamping force or affect the adjacent normal probes. With the split design, it is simple and convenient to replace once damaged, and only a small part needs to be replaced, which also reduces the processing difficulty and the cost of use.

[0013] Optionally, the left clamping part and the right clamping part are mirror images of each other. The left clamping part includes a connecting part that is fixedly connected to the claw arm at one end, a wedge-shaped head extending from the other end of the connecting part, and a clamping piece disposed on the top of the wedge-shaped head. The clamping piece is inserted between the probes, and as the left claw arm and the right claw arm close, the two opposing clamping pieces clamp the probes.

[0014] Optionally, the left clamping part and the right clamping part are made of tungsten carbide.

[0015] Because of the split design, the clamping part can be made of materials with high heat resistance and strength, thus improving its service life.

[0016] Optionally, the bottom edge of the clamping plate is more than 100 micrometers away from the bottom of the probe, and the bottom edge of the laser spot on the probe is more than 100 micrometers away from the bottom of the probe.

[0017] Optionally, the laser is a rectangular spot with a width H of 60-100 micrometers illuminating the probe.

[0018] Optionally, the laser beam irradiates the probe at a height of 200 micrometers.

[0019] Optionally, the thickness d of the single-sided clamping piece is greater than (HT) / 2, where T is the thickness of the probe body.

[0020] Optionally, the thickness of the clamping piece is 40-70 micrometers.

[0021] Optionally, the thickness of the probe is 25-40 micrometers.

[0022] Optionally, the method for obtaining the normal probe that is replaced by the preset solder is as follows: the normal probe is soldered onto the pad of the probe substrate, and then the normal probe is heated and desoldered from the pad by laser. At this time, some solder will remain on the soldering surface of the normal probe, which is the preset solder.

[0023] The technical solution proposed in this invention has the following technical advantages:

[0024] 1) The use of split grippers reduces processing difficulty and cost;

[0025] 2) By changing the heating position of the laser spot, the problem of heat deformation of the needle arm is avoided. The position of the gripper is matched with the laser spot to maximize the shielding of the laser's influence on adjacent probes.

[0026] 3) Using soldered probes solves the problem of insufficient solder when re-inserting probes after desoldering due to the small spacing between adjacent probes, thus improving the strength of the solder joint and increasing the soldering strength and electrical stability of the repair location. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the cantilever probe structure in the background art;

[0028] Figure 2 This is a schematic diagram of the process route for a specific embodiment of the probe replacement method of the cantilever probe card described in this invention.

[0029] Figure 3 This is a schematic diagram of a specific embodiment of the gripper described in this invention;

[0030] Figure 4 This is a schematic diagram of a specific embodiment of the left clamping part and the right clamping part of the present invention;

[0031] Figure 5 This is a schematic diagram of a specific embodiment of the gripper holding the needle body and the laser projection angle described in this invention;

[0032] Figure 6 This is a schematic diagram of a specific embodiment of the clamping plate used to shield the laser spot according to the present invention.

[0033] As shown in the figure:

[0034] 11-Needle body, 12-Needle tip, 13-Cantilever;

[0035] 20-gripper, 21-left side portion, 211-left claw arm, 212-left gripping part, 2121-connecting part, 2122-wedge head, 2123-gripping plate, 221-right gripping part;

[0036] 30 - Probe to be replaced, 40 - Laser, 41 - Laser spot, 50 - Solder, 60 - Pad, 70 - Probe removal substrate, 80 - Replacement probe. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0038] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation and positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] like Figure 2 As shown, the probe replacement method of the cantilever probe card has the following process route: S1: The gripper 20 holds the probe 30 to be replaced, and then the laser 40 heats the solder 50 to desolder it.

[0041] S2: Remove the probe 30 to be replaced, exposing the pad 60 with residual solder 50;

[0042] S3: The gripper 20 moves to the probe extraction substrate 70, clamps the replacement probe 80, and the laser 40 heats and desolders it.

[0043] S4: Remove the replacement probe 80 from the probe substrate 70, at which point some solder 50 will remain on its soldering surface;

[0044] S5: The gripper 20 holds the replacement probe 80 removed in step S4 and moves it to the position of the desoldered pad 60. The laser 40 heats the pad, and the replacement probe 80 is soldered onto the pad 60, completing the probe replacement.

[0045] like Figure 3 and 4 As shown, the gripper 20 includes a left side portion 21 and a right side portion (not shown) that can move towards each other. The left side portion 21 includes a left gripper arm 211 and a left clamping part 212 detachably connected to the left gripper arm 211. The right side portion includes a right gripper arm and a right clamping part 221 detachably connected to the right gripper arm. The left gripper arm 211 and the right gripper arm are functional components that drive the front working area portion (left clamping part 212 and right clamping part 221) to open and close, serving the functions of motion transmission and strength support. In this embodiment, the detachable connection is achieved through fasteners.

[0046] See also Figure 4 The left clamping part 212 and the right clamping part 221 are mirror images. Taking the left clamping part 212 as an example, it includes a connecting part 2121 that is fixedly connected to the claw arm at one end, a wedge-shaped head 2122 that extends from the other end of the connecting part 2121, and a clamping piece 2123 disposed on the top of the wedge-shaped head 2122. The clamping piece 2123 is inserted between the probes. As the left claw arm 211 and the right claw arm 222 close, the two opposing clamping pieces 2123 clamp the probes. The materials of the left clamping part 212 and the right clamping part 222 are tungsten carbide.

[0047] like Figure 5 As shown, the gripper 20 clamps the needle body 11 from behind the probe. The heating laser 40 irradiates the clamping position of the clamping plate 2123 from above the gripper 20 at an angle downward. In this embodiment, the angle between the laser projection angle and the horizontal plane is about 60°. The laser spot of the laser 40 is located in the area where the two clamping plates 2123 are located. The height h between the bottom edge of the clamping plate 2123 and the bottom of the probe is about 100 micrometers. In this embodiment, the edge of the laser spot 41 irradiated on the probe is higher than the bottom edge of the clamping plate 2123. The height of the laser irradiation on the probe is 200 micrometers.

[0048] like Figure 6 As shown, the laser is a rectangular spot, and the width H of the laser beam on the probe is 80 micrometers. The thickness d of the clamping piece 2123 is 55 micrometers, and the thickness T of the needle body 11 is 28 micrometers. Therefore, the thickness d of the clamping piece 2123 is greater than (HT) / 2.

[0049] The probe replaced in this embodiment may be due to a faulty probe, or it may be a probe with specific performance required.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for replacing probes on a cantilever probe card, characterized in that, The device includes grippers that hold the probe body from behind, and a heating laser that shines from above the grippers at an angle downwards onto the gripper holding position. The laser spot is located within the area where the two grippers are located, and the welding surface of the normal probe body used for replacement is pre-soldered with solder.

2. The probe replacement method for the cantilever probe card according to claim 1, characterized in that, The gripper includes a left side portion and a right side portion that can move towards each other. The left side portion includes a left gripper arm and a left gripping part that is detachably connected to the left gripper arm. The right side portion includes a right gripper arm and a right gripping part that is detachably connected to the right gripper arm.

3. The probe replacement method for the cantilever probe card according to claim 2, characterized in that, The left and right clamping parts are mirror images of each other. The left clamping part includes a connecting part that is fixedly connected to the claw arm at one end, a wedge-shaped head extending from the other end of the connecting part, and a clamping plate disposed on the top of the wedge-shaped head. The clamping plate is inserted between the probes. As the left and right claw arms close, the two opposing clamping plates clamp the probes.

4. The probe replacement method for the cantilever probe card according to claim 3, characterized in that, The bottom edge of the clamping plate is more than 100 micrometers away from the bottom of the probe, and the bottom edge of the laser spot on the probe is more than 100 micrometers away from the bottom of the probe.

5. The probe replacement method for the cantilever probe card according to claim 3, characterized in that, The thickness d of the single-sided clamping plate is greater than (HT) / 2, where H is the width of the laser irradiation on the probe and T is the thickness of the probe body.

6. The probe replacement method for the cantilever probe card according to claim 2, characterized in that, The left and right clamping parts are made of tungsten carbide.

7. The probe replacement method for the cantilever probe card according to claim 1, characterized in that, The laser is a rectangular spot, and the width H of the spot on the probe is 60-100 micrometers.

8. The probe replacement method for the cantilever probe card according to claim 7, characterized in that, The thickness of the probe needle body is 25-40 micrometers.

9. The probe replacement method for the cantilever probe card according to claim 1, characterized in that, The angle between the laser projection angle and the horizontal plane is 20°~80°.

10. The probe replacement method for the cantilever probe card according to claim 1, characterized in that, The method for obtaining the normal probe that is to replace the preset solder is as follows: the normal probe is soldered onto the pad of the probe substrate, and then the normal probe is heated and desoldered from the pad by laser. At this time, some solder will remain on the soldering surface of the normal probe, which is the preset solder.

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