Thin film probe card structure and method for balancing elastic coefficient difference between probes

Abstract

The invention relates to a thin film probe card structure and method for balancing elastic coefficient difference between probes. The thin film probe card structure comprises a support body, a thin film (1), a signal metal layer (11), a grounding metal layer (12), a grounding probe (2) and a signal probe (3), wherein the support body is provided with an acting surface; the thin film (1) covers the acting surface; the signal metal layer (11) is divided into first wires (111) corresponding to the signal probes (3), and the signal probes (3) are electrically connected with the corresponding first wires (111). The device is characterized in that the grounding probes (2) are electrically connected with the grounding metal layer (12) through an elastic coefficient balancing structure, so that the elastic coefficient of each grounding probe (2) tends to approach the elastic coefficient of the signal probe (3).

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor detection probe cards, and in particular to a thin film probe card structure for balancing the difference in elastic coefficients between needles. Background Art

[0002] In recent years, with the development and popularization of 5G and big data technologies, the operating frequency of semiconductor devices has continued to increase, and high-frequency wafer-level testing has gradually become an indispensable part of chip production. The thin film probe card adopts an integrated molding process to directly make the probe and signal line on a thin film, which greatly reduces the parasitic problems in the needle card test process, shortens the signal transmission path, reduces the impedance discontinuity, has excellent signal integrity, and is widely used in RF wafer testing.

[0003] During the test, the point where the first probe contacts the wafer to produce a needle mark or electrical conduction is usually taken as the zero point. On this basis, a Z-direction stroke needs to be applied to ensure that each probe can stably and reliably contact the tested pad or bump to complete the test.

[0004] like Figure 1 As shown, in general, the film is provided with two metal structures, a signal metal layer 11 and a ground metal layer 12; the signal metal layer 11 is composed of a signal line 111 and a ground plane: the signal line 111 is a cantilever line structure, electrically connected to the signal probe 3, and separated and insulated from the ground plane or other signal lines; the ground plane is a metal plane, electrically connected to the ground probe 2, and the corresponding signal line position is hollowed out. The ground plane is electrically connected to the ground metal layer 12 through the via 4. In this structure, there is a difference in the metal area of ​​the signal layer corresponding to the signal probe 3 and the ground probe 2, which leads to inconsistent elastic coefficients of the probes. When the same test stroke is applied, there are often problems such as insufficient contact force of the signal probe, too shallow needle marks, unstable signals, etc., and it is necessary to test by increasing the test OD or increasing the elastic force, which brings risks such as crushing the PAD or bump, uneven needle marks, needle mark misses, and reduced life. Summary of the invention

[0005] The object of the present invention is to provide a thin film probe card structure to balance the difference in elastic coefficients between probes, thereby improving the consistency of contact performance.

[0006] In order to achieve the above-mentioned purpose, the product technical solution adopted by the present invention is: a thin film probe card structure for balancing the difference in elastic coefficients between needles, including a support body providing an active surface, a thin film covering the active surface, a signal metal layer and a grounding metal layer separated and arranged in the thickness direction inside the thin film, and a grounding probe and a signal probe 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 the corresponding first wire; the grounding probe is electrically connected to the grounding metal layer through a balanced elastic coefficient structure so that the elastic coefficient at each grounding probe tends to be close to the elastic coefficient at the signal probe.

[0007] In the above scheme, the balanced elastic coefficient structure includes a first conductive plane separated on the signal metal layer, the ground probe is electrically connected to the first conductive plane, and one or more leakage slots are opened around each ground probe on the first conductive plane; the first conductive plane (113) is electrically connected to the ground metal layer. Further, the leakage slots are arranged on the first conductive plane, so that the first conductive plane has a grid structure. Specifically, the shape and number of the leakage slots are not limited.

[0008] In the above solution, the balanced elastic coefficient structure includes a second wire separated from the signal metal layer, the ground probe is electrically connected to the second wire corresponding to the ground probe, and the second wire is electrically connected to the ground metal layer.

[0009] In the above solution, the balanced elastic coefficient structure includes a second conductive plane separated on the ground metal layer, the ground probe is electrically connected to the second conductive plane, and one or more drain grooves are opened around the via holes of each ground probe on the second conductive plane. Further, the drain grooves are arranged on the second conductive plane, so that the second conductive plane has a grid structure.

[0010] In the above solution, the balanced elastic coefficient structure includes a third wire separated from the ground metal layer, and the ground probe is electrically connected to the corresponding third wire.

[0011] In the above solution, it is also preferred that the leakage groove is an arc-shaped groove surrounding the grounding probe.

[0012] In the above solution, the separation area between the wires on the signal metal layer and the ground metal layer and the drain groove are all filled with a thin film material (PI material).

[0013] In the above solution, the via refers to one or more conductors distributed between the signal metal layer and the ground metal layer, which are used to achieve electrical connection of the signal.

[0014] To achieve the above-mentioned purpose, the method and technical scheme adopted by the present invention is: a method for balancing the difference in elastic coefficients between needles applied to a thin film probe card structure, adopting the above-mentioned structural technical scheme, and by controlling the area and proportion of the metal layer connected to each grounding probe, the elastic coefficient difference δ between the elastic coefficient K1 of each grounding probe and the elastic coefficient K2 of the signal probe is within the range of ±0.5K1; wherein 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.

[0015] In the above solution, when the ground probes and the signal probes are arranged in an array, the leakage area ratio around the probes located inside the array is set to be greater than the leakage area ratio around the probes outside the array.

[0016] The present invention proposes a thin film probe card structure and method for balancing the difference in elastic coefficients between needles, designs the specific structures of the signal metal layer and the grounding metal layer, reduces the difference in elastic coefficients between the grounding probes and the signal probes by controlling the area and proportion of the metal layer connected to each grounding probe, and effectively reduces the test stroke required for contact from the first needle to the last needle, making the needle marks of the probes more consistent during the test process, avoiding problems such as local needle marks being too deep, too shallow or missing, reducing the risk of wafer damage and test signal loss, and having strong process feasibility without adding additional cost and difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of a cross-section of a thin film in the prior art; Figure 2 A schematic diagram of the relative positions of a signal probe, a ground probe and a signal metal layer in the prior art; Figure 3 Schematic diagram of the relative positions of a signal probe, a ground probe and a signal metal layer according to a first embodiment of the present invention; Figure 4 Schematic diagram of the relative positions of the signal probe, the ground probe and the signal metal layer according to the second embodiment of the present invention; Figure 5 Schematic diagram of the relative positions of the signal probe, the ground probe and the signal metal layer according to the third embodiment of the present invention; Figure 6 Schematic diagram of the relative positions of the signal probe, the ground probe and the signal metal layer according to the fourth embodiment of the present invention; Figure 7 Schematic diagram of the relative positions of the signal probe, the ground probe and the signal metal layer according to the fifth embodiment of the present invention; Figure 8 Schematic diagram of the relative positions of the signal probe, the ground probe and the signal metal layer according to the sixth embodiment of the present invention; Fig. 9 For Figure 8Schematic diagram of the corresponding ground metal layer; Fig.10 Schematic diagram of the relative positions of the signal probe, the ground probe and the signal metal layer according to the seventh embodiment of the present invention; Fig.11 For Fig.10 Schematic diagram of the corresponding ground metal layer.

[0018] In the above attached figure: 1. Film; 11. Signal metal layer; 111. First conductor; 112. Second conductor; 113. First conductive plane; 114. Third conductive plane; 12. Ground metal layer; 121. Second conductive plane; 2. Ground probe; 3. Signal probe; 4. Vias; 5. Leakage slot; 6. Avoidance groove. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Example 1, see Figure 1 and Figure 3 As shown: A thin film probe card structure for balancing the difference in elastic coefficients between needles 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 and arranged 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.

[0020] The cross section of the film 1 is as follows Figure 1 As shown, a signal metal layer 11 and a ground metal layer 12 are provided inside the device, and the signal metal layer 11 is closer to the ground probe 2 and the signal probe 3 than the ground metal layer 12 .

[0021] See also Figure 3 As shown, the signal metal layer 11 is divided into a first wire 111 corresponding to the signal probe 3, the signal probe 3 is electrically connected to the corresponding first wire 111, and the ground probe 2 is electrically connected to the ground metal layer 12 through a balanced elastic coefficient structure. The balanced elastic coefficient structure includes a first conductive plane 113 divided on the signal metal layer 11, the ground probe 2 is electrically connected to the first conductive plane 113, and one or more drain grooves 5 are opened around each ground probe 2 on the first conductive plane 113. In other words, the signal metal layer 11 is divided into the first conductive wire 111 and the first conductive plane 113.

[0022] In practice, the first conductor 111 corresponds to the signal probe 3. When there are multiple signal probes, there also need to be multiple first conductors 111. Usually, only one first-layer conductive plane 113 is required. 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 shows only one grounding probe 2.

[0023] In practice, the number and relative positions of the ground probes 2 and the signal probes 3 can be designed according to the actual conditions of the chip under test.

[0024] Specifically, Figure 3 As shown, a plurality of drain slots 5 are arranged on the first conductive plane 113, so that the first conductive plane 113 has a grid structure. In addition, the first conductive plane 113 is electrically connected to the ground metal layer 12 through the via 4. Specifically, the via 4 is preferably arranged at a peripheral position of the first conductive plane 113. The via 4 refers to a conductor connected between the signal metal layer 11 and the ground metal layer 12, and is used to realize signal electrical connection.

[0025] By adjusting the size and arrangement shape of the leakage groove 5, the elastic coefficient at each grounding probe 2 tends to be close to 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 the range of ±0.5K1; wherein 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.

[0026] In practice, the elastic coefficient K1 of each ground probe 2 and the elastic coefficient K2 of each signal probe 3 can be measured using a needle card analyzer such as PrecisionWoRx VX4.

[0027] When in use, the signal probe 3 is electrically connected to the first conductive wire 111 to receive an electrical signal, and the grounding probe 2 is grounded via the first conductive plane 113 , the via 4 , and the grounding metal layer 12 .

[0028] Example 2, see Figure 1 and Figure 4 As shown: A thin film probe card structure for balancing the difference in elastic coefficients between needles 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 and arranged 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 structure is different from the first embodiment in that: the leakage grooves 5 are multiple and distributed around the ground probe 2, and the vias 4 are arranged in an array.

[0029] The rest is the same as in the first embodiment and will not be described again here.

[0030] Example 3, see Figure 1 and Figure 5 As shown: A thin film probe card structure for balancing the difference in elastic coefficients between needles 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 and arranged 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 structure is different from the first embodiment in that the leakage groove 5 is an arc groove surrounding the ground probe 2, and the vias 4 are arranged in an array.

[0031] The rest is the same as in the first embodiment and will not be described again here.

[0032] Example 4, see Figure 1 and Figure 6 As shown: A thin film probe card structure for balancing the difference in elastic coefficients between needles, comprising 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 and arranged 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 the first embodiment is that: the leakage groove 5 is a linear groove arranged on both sides of the ground probe 2, and the vias 4 are arranged in an array, and the number of the ground probes 2 is specifically three.

[0033] The rest is the same as in the first embodiment and will not be described again here.

[0034] Example 5, see Figure 1 and Figure 7 As shown: A thin film probe card structure for balancing the difference in elastic coefficients between needles 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 and arranged 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 the first embodiment is that: the balanced elastic coefficient structure includes a second wire 112 divided on the signal metal layer 11, the ground probe 2 is electrically connected to the corresponding second wire 112; the second wire 112 is electrically connected to the ground metal layer 12 through a via 4.

[0035] When in use, the signal probe 3 is electrically connected to the first wire 111 to receive an electrical signal, and the grounding probe 2 is grounded via the second wire 112 , the via 4 , and the grounding metal layer 12 .

[0036] The rest is the same as in the first embodiment and will not be described again here.

[0037] Example 6, see Figure 1 , Figure 8 and Fig. 9 As shown: A thin film probe card structure for balancing the difference in elastic coefficients between needles, comprising 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 and arranged 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 the first embodiment is that the structure for balancing the elastic coefficients includes a third wire 114 (see Fig. 9 As shown), the ground probe 2 is electrically connected to its corresponding third wire 114 through the via 4 (combined with Figure 8 and Fig. 9 ).

[0038] That is, the third conductive line 114 is disposed on the ground metal layer 12 , and the first conductive line 111 is disposed on the signal metal layer 11 .

[0039] Furthermore, the signal metal layer 11 is provided with an escape groove 6 at a position corresponding to the ground probe 2 , so that the ground probe 2 is completely separated from the signal metal layer 11 , and the ground metal layer 12 directly provides the main elasticity thereof.

[0040] When in use, the signal probe 3 is electrically connected to the first wire 111 to receive an electrical signal, and the grounding probe 2 passes through the hole and the third wire 114 to be grounded.

[0041] The rest is the same as in the first embodiment and will not be described in detail here. The same effect as in the first embodiment can be achieved.

[0042] Embodiment 7, see Figure 1 , Fig.10 and Fig.11 As shown: A thin film probe card structure for balancing the difference in elastic coefficients between needles, comprising 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 and arranged 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 the first embodiment is that the balanced elastic coefficient structure includes a second conductive plane 121 (see Fig.11 ), the ground probe 2 is electrically connected to the second conductive plane 121 through the via 4 (combined with Fig.10 and Fig.11 ), and a plurality of drain slots 5 are provided around the via holes of each ground probe 2 on the second conductive plane 121. Specifically, the drain slots 5 are arranged on the second conductive plane 121, so that the second conductive plane 121 has a grid structure. Fig.11 .

[0043] Furthermore, the signal metal layer 11 is provided with an escape groove 6 at a position corresponding to the ground probe 2 , so that the ground probe 2 is completely separated from the signal metal layer 11 , and the ground metal layer 12 directly provides the main elasticity thereof.

[0044] When in use, the signal probe 3 is electrically connected to the first conductive wire 111 to receive an electrical signal, and the grounding probe 2 passes through the hole 4 and the second conductive plane 121 to be grounded.

[0045] The rest is the same as in the first embodiment and will not be described in detail here. The same effect as in the first embodiment can be achieved.

[0046] Example 8, see Figure 1 , Figure 3 As shown: A method for balancing the difference in elastic coefficients between needles applied to a thin film probe card structure, using the thin film probe card structure of one of embodiments 1 to 7, and then controlling the area and proportion of the metal layer connected to each grounding probe 2 so 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 the range of ±0.5K1; wherein 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.

[0047] Regarding "by controlling the area and proportion of the metal layer connected to each ground probe 2", the specific measures are: for the structures of the above-mentioned embodiments five and six, the wire widths of the second wire 112 and the third wire 114 are adjusted, and for the structures of embodiments one to four and seven, the area size of the leakage groove 5 is adjusted. By increasing or decreasing the area of ​​the leakage groove 5, the area proportion of the metal connected to the ground probe 2 can be changed accordingly.

[0048] Specifically, when the ground probes 2 and the signal probes 3 are arranged in an array, the proportion of the empty area around the probes located inside the array is set to be greater than the proportion of the empty area around the probes outside the array.

[0049] In practice, the elastic coefficient K1 of each ground probe 2 and the elastic coefficient K2 of the signal probe 3 can be measured using a pin card analyzer such as PrecisionWoRx VX4.

[0050] The above embodiments are only the best examples, and the actual embodiments include the following changes: In practice, according to actual needs, the signal metal layer 11 and the grounding metal layer 12 in the film 1 can be inverted, that is, the grounding metal layer 12 is arranged closer to the grounding 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 and then be electrically connected to the signal metal layer 11 on the rear side, while the grounding probe 2 can be directly in contact with the grounding metal layer 12 and electrically connected, but it can also achieve the same effect as the above-mentioned embodiment.

[0051] The embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A thin film probe card structure for balancing the difference in elastic coefficients between needles, comprising 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 and arranged 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 separated on the signal metal layer (11), and the signal probe (3) is electrically connected to the corresponding first wire (111); the characteristics are: The grounding probe (2) is electrically connected to the grounding metal layer (12) via 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 coefficients between needles according to claim 1, characterized in that: The balanced elastic coefficient structure comprises a first conductive plane (113) separated on a signal metal layer (11), the ground probe (2) being electrically connected to the first conductive plane (113), and one or more leakage slots (5) being provided around each ground probe (2) on the first conductive plane (113); the first conductive plane (113) being electrically connected to a ground metal layer (12).

3. The thin film probe card structure for balancing the difference in elastic coefficients between needles according to claim 2, characterized in that: The drain grooves (5) are arranged on the first conductive plane (113), so that the first conductive plane (113) presents a grid-like structure.

4. The thin film probe card structure for balancing the difference in elastic coefficients between needles according to claim 1, characterized in that: The balanced elastic coefficient structure comprises a second wire (112) segmented from a signal metal layer (11), the grounding probe (2) being electrically connected to its corresponding second wire (112); and the second wire (112) being electrically connected to the grounding metal layer (12).

5. The thin film probe card structure for balancing the difference in elastic coefficients between needles according to claim 1, characterized in that: The balanced elastic coefficient structure comprises a second conductive plane (121) segmented on a ground metal layer (12), the ground probe (2) being electrically connected to the second conductive plane (121), and one or more leakage slots (5) being provided around the via holes of each ground probe (2) on the second conductive plane (121).

6. The thin film probe card structure for balancing the difference in elastic coefficients between needles according to claim 5, characterized in that: The drain grooves (5) are arranged on the second conductive plane (121), so that the second conductive plane (121) presents a grid-like structure.

7. The thin film probe card structure for balancing the difference in elastic coefficients between needles according to claim 1, characterized in that: The balanced elastic coefficient structure comprises a third wire (114) separated from a ground metal layer (12), and the ground probe (2) is electrically connected to the corresponding third wire (114).

8. The thin film probe card structure for balancing the difference in elastic coefficients 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 the range of ±0.5K1; wherein 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 equalizing the difference in elastic coefficient between needles applied to a thin film probe card structure, characterized in that: A thin film probe card structure according to any one of claims 1 to 7 is adopted, and by controlling the area and proportion of the metal layer connected to each grounding probe (2), 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 the range of ±0.5K1; wherein 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.

10. The method for balancing the difference in elastic coefficients between needles applied to a thin film probe card structure according to claim 1, characterized in that: When the ground probes (2) and the signal probes (3) are arranged in an array, the proportion of the empty space around the probes located inside the array is set to be greater than the proportion of the empty space around the probes outside the array.

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