Membrane probe card structure and method for balancing elastic coefficient differences between probes
By setting a balanced elastic coefficient structure on the signal metal layer and the ground metal layer of the thin-film probe card, the problem of inconsistent contact force caused by the difference in probe elastic coefficient is solved, and the uniformity of probe contact force and the stability of test signal are achieved.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- MAXONE SEMICON CO LTD
- Filing Date
- 2025-08-15
- Publication Date
- 2026-07-30
AI Technical Summary
In existing thin-film probe cards, the difference in elastic coefficients between signal probes and ground probes leads to inconsistent contact forces, resulting in problems such as uneven needle marks and unstable signals during testing.
By setting a balanced elastic coefficient structure on the signal metal layer and the ground metal layer, including opening a slot in the conductive plane or adjusting the wire width, the difference between the elastic coefficient of each ground probe and the signal probe is controlled within ±0.5K1, thereby reducing the elastic coefficient difference.
It achieves consistent probe contact force, avoids problems of probe marks being too shallow or too deep, reduces the risk of pad damage or bumping, and improves the stability of test signals and probe lifespan.
Smart Images
Figure CN2025115008_30072026_PF_FP_ABST
Abstract
Description
A thin-film probe card structure and method for balancing the difference in elastic coefficient between needles Technical Field
[0001] This invention relates to the field of semiconductor detection probe card technology, and in particular to a thin-film probe card structure that balances the difference in elastic coefficient between probes. Background Technology
[0002] In recent years, with the development and popularization of 5G and big data technologies, the operating frequency of semiconductor devices has been continuously increasing. High-frequency wafer-level testing has gradually become an indispensable part of chip production. Thin-film probe cards adopt an integrated molding process, directly fabricating probes and signal lines on a thin film, which greatly reduces parasitic problems in the probe card testing process, shortens the signal transmission path, reduces impedance discontinuities, and has excellent signal integrity. It is widely used in RF wafer testing.
[0003] During the test, the first probe is usually used as the zero point when it makes contact with the wafer to create a pin mark or electrical continuity. Based on this, a Z-axis stroke needs to be applied to ensure that each probe can make stable and reliable contact with the solder pad or bump under test to complete the test.
[0004] As shown in Figure 1, the thin film typically contains two metal layers: a signal metal layer 11 and a ground metal layer 12. The signal metal layer 11 consists of a signal line 111 and a ground plane. The signal line 111 is a cantilevered wire structure, electrically connected to the signal probe 3, and insulated from the ground plane or other signal lines. The ground plane is a metal plane, electrically connected to the ground probe 2, with a cutout corresponding to the signal line position. The ground plane is electrically connected to the ground metal layer 12 through a via 4. In this structure, the metal areas of the signal layer corresponding to the signal probe 3 and the ground probe 2 differ, leading to inconsistent elastic coefficients of the probes. Under the same test stroke, problems such as insufficient contact force of the signal probe, shallow needle marks, and unstable signals often occur. Testing requires methods such as increasing the test OD or increasing the elastic force, which can lead to risks such as pad damage or bumps, uneven needle marks, needle mark misses, and reduced lifespan. Summary of the Invention
[0005] The purpose of this invention is to provide a thin-film probe card structure that balances the differences in elastic coefficients between probes, thereby improving the consistency of contact performance.
[0006] To achieve the above objectives, the product technical solution adopted by the present invention is: a thin film probe card structure for balancing the difference in elastic coefficient between probes, comprising a support providing an active surface, a thin film covering the active surface, a signal metal layer and a ground metal layer separated in the thickness direction inside the thin film, and ground probes and signal probes protruding from the surface of the thin film; a first wire corresponding to the signal probe is divided on the signal metal layer, and the signal probe is electrically connected to its corresponding first wire; the ground probe is electrically connected to the ground metal layer through a balanced elastic coefficient structure, so that the elastic coefficient at each ground probe tends to be close to the elastic coefficient at the signal probe.
[0007] In the above scheme, the equalization elastic coefficient structure includes a first conductive plane segmented on the signal metal layer. The grounding probe is electrically connected to the first conductive plane, and one or more drain slots are formed around each grounding probe on the first conductive plane. The first conductive plane (113) is electrically connected to the ground metal layer. Further, the drain slots are arranged on the first conductive plane, making the first conductive plane have a grid-like structure. Specifically, the shape and number of the drain slots are not limited.
[0008] In the above scheme, the equalization elastic coefficient structure includes a second conductor segmented on the signal metal layer, and the grounding probe is electrically connected to its corresponding second conductor; the second conductor is electrically connected to the ground metal layer.
[0009] In the above scheme, the balanced elastic coefficient structure includes a second conductive plane segmented on the grounding metal layer. The grounding probe is electrically connected to the second conductive plane, and one or more drainage grooves are formed around the vias of each grounding probe on the second conductive plane. Furthermore, the drainage grooves are arranged on the second conductive plane, making the second conductive plane have a grid-like structure.
[0010] In the above scheme, the balanced elastic coefficient structure includes a third conductor segmented on the grounding metal layer, and the grounding probe is electrically connected to its corresponding third conductor.
[0011] In the above scheme, it is preferable that the leakage groove is an arc-shaped groove surrounding the grounding probe.
[0012] In the above scheme, the separation area between the conductors on the signal metal layer and the ground metal layer, as well as the leakage groove, are all filled with thin film material (PI material).
[0013] In the above scheme, the via refers to one or more conductors distributed between the signal metal layer and the ground metal layer, used to realize the electrical connection of the signal.
[0014] To achieve the above objectives, the present invention employs the following technical solution: a method for balancing the difference in elastic coefficients between probes in a thin-film probe card structure. This method utilizes the aforementioned structural technical solution and controls the area and proportion of the metal layer connected to each ground probe. The difference δ between the elastic coefficient K1 of each ground probe and the elastic coefficient K2 of the signal probe is within ±0.5K1. Here, K1 is the elastic coefficient at the ground probe, with units of g / μm, and K2 is the elastic coefficient at the signal probe, with units of g / μm.
[0015] In the above scheme, when the grounding probes and signal probes are distributed in an array, the proportion of the void area around the probes located inside the array is set to be greater than the proportion of the void area around the probes outside the array.
[0016] This invention proposes a thin-film probe card structure and method for balancing the difference in elastic coefficient between probes. It designs specific structures for the signal metal layer and the ground metal layer. By controlling the area and proportion of the metal layer connected to each ground probe, the difference in elastic coefficient between the ground probe and the signal probe is reduced. This effectively reduces the test stroke required from the first probe to the last probe contact, resulting in more consistent probe marks during testing. It avoids problems such as excessively deep, shallow, or missing local probe marks, reducing the risk of wafer damage and test signal loss. The invention is highly feasible in terms of manufacturing process and does not increase additional cost or difficulty. Attached Figure Description
[0017] Figure 1 is a schematic cross-sectional view of a prior art thin film;
[0018] Figure 2 is a schematic diagram showing the relative positions of the existing signal probe, ground probe, and signal metal layer;
[0019] Figure 3 is a schematic diagram showing the relative positions of the signal probe, the ground probe, and the signal metal layer in Embodiment 1 of the present invention.
[0020] Figure 4 is a schematic diagram showing the relative positions of the signal probe, the ground probe, and the signal metal layer in Embodiment 2 of the present invention.
[0021] Figure 5 is a schematic diagram showing the relative positions of the signal probe, the ground probe, and the signal metal layer in Embodiment 3 of the present invention.
[0022] Figure 6 is a schematic diagram showing the relative positions of the signal probe, the ground probe, and the signal metal layer in Embodiment 4 of the present invention.
[0023] Figure 7 is a schematic diagram showing the relative positions of the signal probe, the ground probe, and the signal metal layer in Embodiment 5 of the present invention.
[0024] Figure 8 is a schematic diagram showing the relative positions of the signal probe, ground probe, and signal metal layer in Embodiment 6 of the present invention;
[0025] Figure 9 is a schematic diagram of the grounding metal layer corresponding to Figure 8;
[0026] Figure 10 is a schematic diagram showing the relative positions of the signal probe, the ground probe, and the signal metal layer in Embodiment 7 of the present invention.
[0027] Figure 11 is a schematic diagram of the grounding metal layer corresponding to Figure 10.
[0028] In the attached diagrams above:
[0029] 1. Thin film; 11. Signal metal layer; 111. First conductor; 112. Second conductor; 113. First conductive plane; 114. Third conductor; 12. Ground metal layer; 121. Second conductive plane;
[0030] 2. Grounding probe;
[0031] 3. Signal probe;
[0032] 4. Via;
[0033] 5. Leakage channel;
[0034] 6. Clearance groove. Detailed Implementation
[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments:
[0036] Example 1, see Figures 1 and 3:
[0037] A thin-film probe card structure for balancing the difference in elastic coefficient between probes includes a support body providing an active surface, a thin film 1 covering the active surface, a signal metal layer 11 and a ground metal layer 12 separated in the thickness direction inside the thin film 1, and a ground probe 2 and a signal probe 3 protruding from the surface of the thin film.
[0038] The cross-section of the thin film 1 is shown in Figure 1. It has a signal metal layer 11 and a ground metal layer 12 inside, and the signal metal layer 11 is closer to the ground probe 2 and the signal probe 3 than the ground metal layer 12.
[0039] Referring to Figure 3, the signal metal layer 11 is segmented to form first conductors 111 corresponding to signal probes 3. The signal probes 3 are electrically connected to their corresponding first conductors 111. The ground probes 2 are electrically connected to the ground metal layer 12 via a balanced elastic coefficient structure. The balanced elastic coefficient structure includes a first conductive plane 113 segmented on the signal metal layer 11. The ground probes 2 are electrically connected to the first conductive plane 113, and one or more slots 5 are formed around each ground probe 2 on the first conductive plane 113. In other words, the signal metal layer 11 is segmented into first conductors 111 and a first conductive plane 113.
[0040] In practice, the first conductor 111 corresponds to the signal probe 3. When there are multiple signal probes, there must also be multiple first conductors 111. The first conductive plane 113 usually only needs one. If there are multiple grounding probes 2, the multiple grounding probes 2 are also distributed and electrically connected on the first conductive plane 113. The example in the figure is a single grounding probe 2.
[0041] In practice, the number and relative positions of the grounding probe 2 and the signal probe 3 can be designed according to the actual situation of the chip under test.
[0042] Specifically, as shown in Figure 3, multiple perforated slots 5 are arranged on the first conductive plane 113, making the first conductive plane 113 have a grid-like structure. Furthermore, the first conductive plane 113 is electrically connected to the ground metal layer 12 via vias 4. Preferably, the vias 4 are located around the periphery of the first conductive plane 113. The vias 4 are conductors connecting the signal metal layer 11 and the ground metal layer 12, used to achieve electrical signal connection.
[0043] By adjusting the size and shape of the perforated slots 5, the elastic coefficient at each grounding probe 2 is made to approach the elastic coefficient at the signal probe 3. Specifically, the difference δ between the elastic coefficient K1 of each grounding probe 2 and the elastic coefficient K2 of the signal probe 3 is within ±0.5K1. Here, K1 is the elastic coefficient at the grounding probe, with units of g / μm, and K2 is the elastic coefficient at the signal probe, with units of g / μm.
[0044] In practice, the elastic coefficient K1 of each grounding probe 2 and the elastic coefficient K2 of each signal probe 3 can be measured using a pin card analyzer such as PrecisionWoRx VX4.
[0045] In use, the signal probe 3 is electrically connected to the first wire 111 to receive electrical signals, while the ground probe 2 is grounded through the first conductive plane 113, the via 4, and the ground metal layer 12.
[0046] Example 2, see Figures 1 and 4:
[0047] A thin-film probe card structure for balancing the difference in elastic coefficient between probes includes a support body providing an active surface, a thin film 1 covering the active surface, a signal metal layer 11 and a ground metal layer 12 separated in the thickness direction inside the thin film 1, and a ground probe 2 and a signal probe 3 protruding from the surface of the thin film. The difference from Embodiment 1 is that the perforated grooves 5 are multiple distributed around the ground probe 2, and the vias 4 are arranged in an array.
[0048] The rest is the same as in Example 1, and will not be repeated here.
[0049] Example 3, see Figures 1 and 5:
[0050] A thin-film probe card structure for balancing the difference in elastic coefficient between probes includes a support body providing an active surface, a thin film 1 covering the active surface, a signal metal layer 11 and a ground metal layer 12 separated in the thickness direction inside the thin film 1, and a ground probe 2 and a signal probe 3 protruding from the surface of the thin film. The difference from Embodiment 1 is that the perforated groove 5 is an arc-shaped groove surrounding the ground probe 2, and the vias 4 are arranged in an array.
[0051] The rest is the same as in Example 1, and will not be repeated here.
[0052] Example 4, see Figures 1 and 6:
[0053] A thin-film probe card structure for balancing the difference in elastic coefficient between probes includes a support body providing an active surface, a thin film 1 covering the active surface, a signal metal layer 11 and a ground metal layer 12 separated in the thickness direction inside the thin film 1, and ground probes 2 and signal probes 3 protruding from the surface of the thin film. The difference from Embodiment 1 is that the perforated groove 5 is a straight groove provided on both sides of the ground probe 2, and the through holes 4 are arranged in an array. Specifically, there are three ground probes 2.
[0054] The rest is the same as in Example 1, and will not be repeated here.
[0055] Example 5, see Figures 1 and 7:
[0056] A thin-film probe card structure for balancing the difference in elastic coefficient between probes includes a support providing an active surface, a thin film 1 covering the active surface, a signal metal layer 11 and a ground metal layer 12 separated in the thickness direction inside the thin film 1, and a ground probe 2 and a signal probe 3 protruding from the surface of the thin film. The difference from Embodiment 1 is that the structure for balancing the elastic coefficient includes a second conductor 112 segmented on the signal metal layer 11, and the ground probe 2 is electrically connected to its corresponding second conductor 112; the second conductor 112 is electrically connected to the ground metal layer 12 through a via 4.
[0057] In use, the signal probe 3 is electrically connected to the first wire 111 to receive electrical signals, while the ground probe 2 is grounded through the second wire 112, the via 4, and the grounding metal layer 12.
[0058] The rest is the same as in Example 1, and will not be repeated here.
[0059] Example 6, see Figures 1, 8 and 9:
[0060] A thin-film probe card structure for balancing the difference in elastic coefficient between probes includes a support providing an active surface, a thin film 1 covering the active surface, a signal metal layer 11 and a ground metal layer 12 separated in the thickness direction inside the thin film 1, and a ground probe 2 and a signal probe 3 protruding from the surface of the thin film. The difference from Embodiment 1 is that the structure for balancing the elastic coefficient includes a third conductor 114 (see Figure 9) segmented on the ground metal layer 12, and the ground probe 2 is electrically connected to its corresponding third conductor 114 through a via 4 (refer to Figures 8 and 9).
[0061] That is, the third conductor 114 is disposed on the ground metal layer 12, and the first conductor 111 is disposed on the signal metal layer 11.
[0062] Furthermore, the signal metal layer 11 is provided with a clearance groove 6 at the position corresponding to the grounding probe 2, so that the grounding probe 2 is completely separated from the signal metal layer 11, and its main elasticity is directly provided by the grounding metal layer 12.
[0063] In use, the signal probe 3 is electrically connected to the first wire 111 to receive an electrical signal, while the ground probe 2 is grounded through a hole and the third wire 114.
[0064] Everything else is the same as in Example 1, and will not be repeated here. It can achieve the same effect as Example 1.
[0065] Example 7, see Figures 1, 10 and 11:
[0066] A thin-film probe card structure for balancing the difference in elastic coefficient between probes includes a support body providing an active surface, a thin film 1 covering the active surface, a signal metal layer 11 and a ground metal layer 12 separated in the thickness direction inside the thin film 1, and ground probes 2 and signal probes 3 protruding from the surface of the thin film. The difference from Embodiment 1 is that the structure for balancing elastic coefficient includes a second conductive plane 121 (see Figure 11) divided on the ground metal layer 12. The ground probes 2 are electrically connected to the second conductive plane 121 through vias 4 (referencing Figures 10 and 11). In addition, multiple drainage grooves 5 are formed around the vias of each ground probe 2 on the second conductive plane 121. Specifically, the drainage grooves 5 are arranged on the second conductive plane 121, making the second conductive plane 121 have a grid-like structure, as shown in Figure 11.
[0067] Furthermore, the signal metal layer 11 is provided with a clearance groove 6 at the position corresponding to the grounding probe 2, so that the grounding probe 2 is completely separated from the signal metal layer 11, and its main elasticity is directly provided by the grounding metal layer 12.
[0068] In use, the signal probe 3 is electrically connected to the first wire 111 to receive the electrical signal, and the grounding probe 2 passes through the hole 4 and the second conductive plane 121 to be grounded.
[0069] Everything else is the same as in Example 1, and will not be repeated here. It can achieve the same effect as Example 1.
[0070] Example 8, see Figures 1 and 3:
[0071] A method for balancing the difference in elastic coefficients between probes in a thin-film probe card structure is provided. The method employs a thin-film probe card structure from one of Examples 1 to 7. By controlling the area and proportion of the metal layer connected to each ground probe 2, the difference δ between the elastic coefficient K1 of each ground probe 2 and the elastic coefficient K2 of the signal probe 3 is made to be within the range of ±0.5K1. Here, K1 is the elastic coefficient at the ground probe, with units of g / μm, and K2 is the elastic coefficient at the signal probe, with units of g / μm.
[0072] The specific measures for "controlling the area and proportion of the metal layer connected to each grounding probe 2" are as follows: For the structures of Embodiments 5 and 6 above, it means adjusting the wire width of the second wire 112 and the third wire 114. For the structures of Embodiments 1 to 4 and Embodiment 7, it means adjusting the area of the slot 5. By increasing or decreasing the area of the slot 5, the area proportion of the metal connected to the grounding probe 2 can be changed accordingly.
[0073] Specifically, when the grounding probe 2 and the signal probe 3 are distributed in an array, the proportion of the void area around the probe located inside the array is set to be greater than the proportion of the void area around the probe located outside the array.
[0074] In practice, the elastic coefficient K1 of each grounding probe 2 and the elastic coefficient K2 of the signal probe 3 can be measured using a pin card analyzer such as PrecisionWoRx VX4.
[0075] The above embodiments are merely best examples, and the following variations are also included in practice:
[0076] In practice, depending on actual needs, the signal metal layer 11 and the ground metal layer 12 in the thin film 1 can be inverted, that is, the ground metal layer 12 is set closer to the ground probe 2 and the signal probe 3 than the signal metal layer 11. In this way, the signal probe 3 needs to pass through the via 4 to be electrically connected to the signal metal layer 11 located on the back side, while the ground probe 2 can be directly contacted and electrically connected to the ground metal layer 12. However, the same effect as the above embodiment can be achieved.
[0077] The embodiments described are merely illustrative of the technical concept and features of the present invention, intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.
Claims
1. A thin-film probe card structure for balancing the difference in elastic coefficient between probes, comprising a support providing an active surface, a thin film (1) covering the active surface, a signal metal layer (11) and a ground metal layer (12) separated in the thickness direction inside the thin film (1), and a ground probe (2) and a signal probe (3) protruding from the surface of the thin film; a first wire (111) corresponding to the signal probe (3) is segmented on the signal metal layer (11), and the signal probe (3) is electrically connected to its corresponding first wire (111); characterized in that: The grounding probe (2) is electrically connected to the grounding metal layer (12) through a balanced elastic coefficient structure, so that the elastic coefficient at each grounding probe (2) tends to be close to the elastic coefficient at the signal probe (3).
2. The thin-film probe card structure for balancing the difference in elastic coefficient between needles according to claim 1, characterized in that: The equal elastic coefficient structure includes a first conductive plane (113) divided on the signal metal layer (11), the grounding probe (2) is electrically connected to the first conductive plane (113), and one or more leakage slots (5) are opened around each grounding probe (2) on the first conductive plane (113); the first conductive plane (113) is electrically connected to the grounding metal layer (12).
3. The thin-film probe card structure for balancing the difference in elastic coefficient between needles according to claim 2, characterized in that: The vent groove (5) is arranged on the first conductive plane (113), so that the first conductive plane (113) has a grid structure.
4. The thin-film probe card structure for balancing the difference in elastic coefficient between needles according to claim 1, characterized in that: The equal elastic coefficient structure includes a second conductor (112) segmented on the signal metal layer (11), and the ground probe (2) is electrically connected to its corresponding second conductor (112); the second conductor (112) is electrically connected to the ground metal layer (12).
5. The thin-film probe card structure for balancing the difference in elastic coefficient between needles according to claim 1, characterized in that: The balanced elastic coefficient structure includes a second conductive plane (121) divided on the ground metal layer (12), the ground probe (2) is electrically connected to the second conductive plane (121), and one or more leakage grooves (5) are opened around the vias of each ground probe (2) on the second conductive plane (121).
6. The thin-film probe card structure for balancing the difference in elastic coefficient between needles according to claim 5, characterized in that: The vent groove (5) is arranged on the second conductive plane (121), so that the second conductive plane (121) has a grid structure.
7. The thin-film probe card structure for balancing the difference in elastic coefficient between needles according to claim 1, characterized in that: The balanced elastic coefficient structure includes a third conductor (114) segmented on the ground metal layer (12), and the ground probe (2) is electrically connected to its corresponding third conductor (114).
8. The thin-film probe card structure for balancing the difference in elastic coefficient between needles according to claim 1, characterized in that: The difference δ between the elastic coefficient K1 of each grounding probe (2) and the elastic coefficient K2 of the signal probe (3) is within ±0.5K1; where K1 is the elastic coefficient at the grounding probe, and its unit is g / μm, and K2 is the elastic coefficient at the signal probe, and its unit is g / μm.
9. A method for balancing the difference in elastic coefficients between probes in a thin-film probe card structure, characterized in that: Using the thin-film probe card structure of any one of claims 1-7, by controlling the area and proportion of the metal layer connected to each ground probe (2), the difference δ between the elastic coefficient K1 of each ground probe (2) and the elastic coefficient K2 of the signal probe (3) is within the range of ±0.5K1; wherein, K1 is the elastic coefficient at the ground probe, and its unit is g / μm, and K2 is the elastic coefficient at the signal probe, and its unit is g / μm.
10. The method for balancing the difference in elastic coefficients between probes applied to a thin-film probe card structure according to claim 1, characterized in that: When the grounding probe (2) and the signal probe (3) are distributed in an array, the proportion of the empty area around the probe located inside the array is set to be greater than the proportion of the empty area around the probe outside the array.