Probe card and preparation method thereof

Abstract

The invention provides a probe card and a preparation method, the probe card comprises a structural assembly and a high-speed signal transmission assembly, the structural assembly comprises a PCB, a space conversion substrate, a guide plate and a plurality of probes, the guide plate is provided with a high-speed guide hole, and the hole wall and the peripheral surface of the high-speed guide hole are metalized to form a metal coating; the high-speed signal transmission assembly comprises a flexible circuit board and a coaxial cable, one end of the flexible circuit board is connected with the metal coating, the other end of the flexible circuit board is connected with the PCB through the coaxial cable to form a high-speed signal transmission channel, and the conventional probe is connected with the PCB through the space conversion substrate. According to the invention, traditional long-path wiring is avoided, high-speed signal loss and delay are reduced, high-speed and conventional channels are distinguished, and test performance and structural compatibility are considered; the preparation method is simple and controllable in process.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor testing, in particular to a probe card and a preparation method thereof. BACKGROUND

[0002] As a key interface instrument between chip and tester, the performance of probe card directly affects the precision, efficiency and reliability of chip testing. A typical probe card usually includes a PCB board 11 (printed circuit board), a space conversion substrate 12 and a probe head 13, as shown in FIG. 1. The probe head 13 comprises an upper guide plate 131, a lower guide plate 132 and a plurality of probes 133. In operation, the tester end of the probe card 13 is connected with the pin of the tester, and the wafer end contacts the wafer test points through the probes, so as to realize the electrical performance detection of the chip by the tester. Figure 1

[0003] As shown in FIG. 2, the part of the probe 133 between the upper guide plate 131 and the lower guide plate 132 is a probe bending section. The bending section produces an elastic effect similar to a spring through its bending deformation, so as to ensure that the probe and the wafer test point form stable and good contact. In order to ensure that the probe bending section has sufficient bending elasticity, the existing technology usually adopts necking (for example, the left probe in FIG. 3) or hollow (for example, the right probe in FIG. 4) design in this area. However, although this structure design can meet the elastic requirement, it causes impedance discontinuity in the signal transmission process due to the sudden change of the cross section of the probe, which significantly increases the signal transmission loss. Figure 2 Figure 2 Figure 2 With the iteration and upgrading of semiconductor technology, the integration of chips is continuously improved, and there are a few channels in some chips that require signal transmission rate. The corresponding probe needs to have high-speed signal transmission capability. However, the signal transmission path of the existing probe card needs to pass through the long-distance transmission path of the probe bending section, the internal wiring of the space conversion substrate and the internal wiring of the PCB in sequence before reaching the tester. The excessively long transmission path itself will aggravate the signal loss, and the impedance discontinuity problem of the above-mentioned probe bending section will make the signal loss increase significantly during the transmission process, and the signal transmission rate cannot meet the high-speed transmission requirement.

[0004] Therefore, how to solve the above-mentioned problems existing in the prior art has become the research and solution of the present application.

[0005] The purpose of the present application is to provide a probe card and a preparation method thereof to solve the above-mentioned problems. SUMMARY

[0006] The purpose of the present application is to provide a probe card and a preparation method thereof to solve the above-mentioned problems.

[0007] ​​​To achieve the above objectives, a first aspect of the present invention provides a probe card, one side of which is used to connect to a testing machine, and the other side is used to contact the test point of the device under test. The probe card includes a structural component and a high-speed signal transmission component.

[0008] The structural components include a PCB board, a space conversion substrate, a guide plate, and multiple probes. One side of the PCB board is connected to a testing machine, and the other side is connected to the space conversion substrate via internal wiring. The space conversion substrate is located on the side of the PCB board facing away from the testing machine. The guide plates are arranged parallel to each other on the side of the space conversion substrate facing away from the testing machine, and multiple guide holes are formed on the guide plates. The probes pass through the corresponding guide holes and are connected to the PCB board via the space conversion substrate. The probes maintain sliding contact with the hole walls of the guide holes.

[0009] At least one of the plurality of guide holes is a high-speed guide hole, and the surface of the hole wall of the high-speed guide hole and the guide plate portion connected thereto is formed with a metal plating layer by a metallization process.

[0010] The high-speed signal transmission component includes a flexible circuit board and a coaxial cable; one end of the flexible circuit board is connected to the metal plating around the high-speed guide hole, and the other end is connected to the PCB board via the coaxial cable.

[0011] The probe inside the high-speed guide hole contacts and engages with the metal plating on the hole wall, and is then connected to the PCB board via the flexible circuit board and coaxial cable to form a high-speed signal transmission channel; other probes are connected to the PCB board through a space conversion substrate to form a conventional signal transmission channel.

[0012] In a further technical solution, at least two guide plates are provided, each guide plate is arranged parallel to each other at intervals, and a guide hole is opened at a corresponding position on each guide plate, and the probe passes vertically through the guide hole on each guide plate.

[0013] In a further technical solution, the high-speed guide hole is located on the part of the guide plate closest to the part under test.

[0014] In a further technical solution, multiple high-speed guide holes are provided and located on the same guide plate.

[0015] In a further technical solution, the distance between the metal plating layers corresponding to adjacent high-speed guide holes is not less than 0.5 mm.

[0016] In a further technical solution, the guide plate is made of ceramic insulating material, and the metal plating layer is prepared by coating, photolithography and electroplating processes.

[0017] In a further technical solution, the coaxial cable is wrapped with a metal shielding layer.

[0018] In a further technical solution, the probe card structure assembly also includes a reinforcing structure, which is mounted on the PCB board on the side opposite to the probe and is used to reinforce the overall structure of the probe card.

[0019] According to a second aspect of the present invention, a method for preparing a probe card is provided, comprising the following steps:

[0020] Step 1: Provide PCB board, space conversion substrate, guide plate, multiple probes, flexible circuit board and coaxial cable;

[0021] Step 2: Open multiple guide holes on the guide plate, select at least one guide hole as a high-speed guide hole, and perform a metallization process on the hole wall of the high-speed guide hole and the surface of the guide plate connected to it to form a metal plating layer.

[0022] Step 3: Place the space conversion substrate on the side of the PCB board away from the test machine, and connect the side of the PCB board away from the test machine to the space conversion substrate through internal traces.

[0023] Step 4: Place the guide plates parallel to each other on the side of the space conversion substrate away from the testing machine to complete the basic assembly of the structural components;

[0024] Step 5: Pass multiple probes through the corresponding guide holes on the guide plate and connect them to the space conversion substrate, and the probes in the high-speed guide holes form a sliding contact with the metal plating on the hole wall;

[0025] Step 6: Connect one end of the flexible circuit board to the metal plating around the high-speed guide hole, and connect the other end of the flexible circuit board to the PCB board via a coaxial cable to form a high-speed signal transmission channel.

[0026] Step 7: Complete the assembly and fixation of each component to obtain the probe card.

[0027] In a further technical solution, prior to step 6, the process includes impedance matching of the flexible circuit board.

[0028] The probe card and its preparation method provided in this application have the following technical advantages:

[0029] The probe card of this invention incorporates a high-speed signal transmission component, metallizing the walls and surrounding area of ​​the high-speed guide hole. This allows the high-speed probe to be directly connected to the PCB board via a metal plating layer, a flexible circuit board, and a coaxial cable, avoiding the long path transmission of traditional probes through spatial conversion substrate traces. This effectively reduces transmission loss and delay of high-speed signals. Furthermore, the combination of the flexible circuit board and coaxial cable further ensures the integrity of high-speed signal transmission, meeting the requirements of high-speed chip testing.

[0030] Furthermore, by distinguishing between high-speed signal transmission channels and conventional signal transmission channels, this invention not only addresses the low-loss transmission problem of a few high-speed probes but also retains the traditional connection method of conventional probes. Under the premise of ensuring high-speed testing performance, it does not require excessive modification to the overall structure of the probe card, thus having a wider range of applications. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of an existing probe card;

[0032] Figure 2 This is a schematic diagram of the probe bending section structure of an existing probe card;

[0033] Figure 3 This is a schematic diagram of the probe card provided in an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram showing the contact and engagement between the probe inside the high-speed guide hole and the metal plating on the hole wall in an embodiment of the present invention;

[0035] In the above figures: 11-PCB board; 12-space conversion substrate; 13-probe head; 131-upper guide plate; 132-lower guide plate; 133-probe; 31-PCB board; 32-space conversion substrate; 33-probe head; 331-upper guide plate; 332-lower guide plate; 333-probe; 34-reinforcing structure; 4-high-speed guide hole; 41-hole wall; 42-metal plating; 5-flexible circuit board; 6-coaxial cable. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0037] The terms "first," "second," etc., used in this article do not specifically refer to order or sequence, nor are they intended to limit this case; they are merely used to distinguish components or operations described using the same technical terms.

[0038] The terms "connection" or "positioning" as used in this article can refer to two or more components or devices making direct physical contact with each other, or making indirect physical contact with each other, or to two or more components or devices operating or moving with each other.

[0039] The terms “include,” “including,” and “have” used in this article are all open-ended, meaning they include but are not limited to.

[0040] The terms “front,” “back,” “up,” “down,” “left,” and “right” used in this article are directional terms. In this case, they are only used to describe the positional relationship between the structures and are not intended to limit the specific direction of the protection scheme or its actual implementation.

[0041] Figure 3 This is a schematic diagram of the probe card provided in an embodiment of the present invention. See also... Figure 3 This application provides a probe card, one side of which is used to connect to a test machine, and the other side is used to contact the test points of the device under test (e.g., a wafer). The probe card mainly includes structural components and high-speed signal transmission components.

[0042] The structural components include a PCB board 31, a space conversion substrate 32, a guide plate, and multiple probes 333. The PCB board 31 extends the dense contact points of the probes 333 to the scale of the testing machine, enabling connection to the testing machine. One side of the PCB board 31 connects to the testing machine, while the other side is electrically connected to the space conversion substrate 32 via internal traces, providing a basic path for signal transmission. The space conversion substrate 32 is fixedly mounted on the side of the PCB board 31 facing away from the testing machine, serving as both a signal converter and structural support.

[0043] The guide plate is arranged parallel to each other on the side of the space conversion substrate 32 away from the test machine. The guide plate has multiple guide holes for accommodating and limiting the probes 333. The multiple probes 333 pass through the guide holes one by one and are connected to the PCB board 31 via the space conversion substrate 32. The probes 333 maintain sliding contact with the hole wall of the guide hole to ensure that the probes 333 have a certain elastic deformation space to adapt to the contact requirements of the test piece.

[0044] Of the aforementioned guide holes, at least one is a high-speed guide hole 4, such as... Figure 4As shown, the hole wall 41 of the high-speed guide hole 4 and the surface of the guide plate connected thereto are metallized to form a metal plating layer 42, providing a reliable electrical connection carrier for high-speed signal transfer. The range of the metal plating layer 42 can be set as needed, for example, within a radius of 2 mm around the high-speed guide hole 4 on the upper and lower surfaces of the guide plate. When the high-speed guide hole 4 is close to the side of the guide plate, the metal plating layer 42 can also be applied to the side of the guide plate near the high-speed guide hole 4.

[0045] The high-speed signal transmission component includes a flexible circuit board 5 (FPC) and a coaxial cable 6; one end of the flexible circuit board 5 is connected to the metal plating layer 42 around the high-speed guide hole 4 by soldering, and the other end is connected to the PCB board 31 via the coaxial cable 6.

[0046] The probe 333 inside the high-speed guide hole 4 contacts and engages with the metal plating layer 42 of the hole wall 41, and is then connected to the PCB board 31 via the flexible circuit board 5 and the coaxial cable 6 in sequence to form a high-speed signal transmission channel; the remaining conventional probes 333 are connected to the PCB board 31 through the space conversion substrate 32 to form a conventional signal transmission channel, realizing the partitioned transmission of high-speed and conventional signals.

[0047] This embodiment sets up a high-speed signal transmission component and metallizes the hole wall 41 and surrounding area of ​​the high-speed guide hole 4, so that the high-speed probe 333 is directly connected to the PCB board 31 via the metal plating layer 42, the flexible circuit board 5 and the coaxial cable 6. This effectively avoids the long path routing that needs to pass through the space conversion substrate 32 in the traditional solution, greatly shortens the transmission distance of the high-speed signal, and significantly reduces signal transmission loss and delay. At the same time, since the flexible circuit board 5 and the coaxial cable 6 can easily achieve impedance continuity, the loss can be extremely low.

[0048] By distinguishing between high-speed signal channels and conventional signal channels, the traditional connection method of conventional probe 333 is retained while ensuring the low-loss transmission performance of a few high-speed probe 333s. This eliminates the need for excessive modifications to the overall structure of the probe 333 card, effectively adapting to the testing scenarios of different types of chips and improving the versatility of the probe 333 card.

[0049] In addition, the metal plating layer 42 on the guide plate cleverly solves the technical problem that the insulating guide plate cannot achieve a reliable electrical connection with the high-speed probe 333 and the flexible circuit board 5, ensuring the continuity and stability of the high-speed signal transmission path and further guaranteeing the accuracy of high-speed testing.

[0050] In this embodiment, two guide plates are provided, including an upper guide plate 331 and a lower guide plate 332. The upper guide plate 331, the lower guide plate 332, and the probe 333 together form the probe head 33. In other possible embodiments, more guide plates may be provided according to actual testing requirements. The upper guide plate 331 and the lower guide plate 332 are arranged parallel to each other vertically, and each guide plate has a corresponding guide hole. The probe 333 passes vertically through the corresponding guide hole on each guide plate. The design of the upper and lower guide plates 332 can limit the probe 333 at multiple points, effectively restricting the radial displacement of the probe 333 and ensuring stable contact between the probe 333 and the test point of the device under test. At the same time, the probe 333 section between the guide plates can bend and deform, thereby ensuring that the end of the probe 333 can always maintain good contact with the wafer waiting to be tested during the testing process, improving the reliability of the test.

[0051] In this embodiment, the high-speed guide hole 4 is located on the guide plate closest to the part under test, i.e. Figure 3 The lower guide plate 332 is arranged in this way. This arrangement allows the high-speed signal transmission path to avoid the bent section of the probe 333, thus avoiding the impedance discontinuity problem caused by the bent structure of the probe 333 and reducing signal transmission loss. At the same time, it can minimize the signal transmission path of the high-speed probe 333 from contact with the test piece to the metal plating layer 42, reduce signal attenuation on the probe 333, and further improve the integrity of high-speed signal transmission.

[0052] More preferably, the guide hole located at the edge of the lower guide plate 332 can be selected as the high-speed guide hole 4. This position facilitates the welding of the flexible circuit board 5 and the metal plating layer 42, effectively reducing the assembly difficulty.

[0053] Multiple high-speed guide holes 4 can be set according to the actual needs of the high-speed test channel, and multiple high-speed guide holes 4 can all be located on the same guide plate, for example, all set on the lower guide plate 332. With this setting, only the guide plate needs to be metallized, and there is no need to process all guide plates, which effectively simplifies the processing technology and reduces production costs.

[0054] To prevent short circuits between the metal plating layers 42 of adjacent high-speed channels and to avoid signal crosstalk, the distance between the metal plating layers 42 corresponding to adjacent high-speed guide holes 4 is not less than 0.5 mm, ensuring that each high-speed signal transmission channel works independently.

[0055] In this embodiment, the guide plate is made of ceramic insulating material, specifically silicon nitride (Si3N4). This material has excellent insulation properties, high temperature resistance and structural stability, which can effectively prevent short circuits between adjacent probes 333 and ensure that the guide plate is not easily deformed during the test.

[0056] The metal coating 42 is prepared by coating, photolithography and electroplating processes. At present, the metallization technology of the guide plate is relatively mature. Metal lines can be precisely grown at specific positions of the guide plate by coating, photolithography and electroplating. The processing accuracy can reach the micron level or even the submicron level, which can meet the high-precision connection requirements of high-speed signal transmission.

[0057] A common metallization process for a guide plate includes: depositing a PVD seed layer on the hole wall and surrounding surface of the high-speed guide hole on the guide plate, followed by coating with adhesive, photolithography to prepare the adhesive film, electroplating with metal, stripping off the adhesive, and finally etching away the excess seed layer to obtain the desired metal coating 42.

[0058] In addition, the coaxial cable 6 in this embodiment is wrapped with a metal shielding layer, which can effectively isolate external electromagnetic interference, prevent high-speed signals from being distorted during transmission, ensure the integrity and stability of high-speed signal transmission, and reduce transmission loss.

[0059] In a further technical solution, the probe 333 card structure assembly also includes a reinforcing structure. This reinforcing structure is mounted on the side of the PCB board 31 away from the probe 333 to reinforce the overall structure of the probe 333 card, effectively suppressing the deformation of the probe 333 card and ensuring that the probe 333 card can still work stably even under heavy loads, thereby improving the stability and reliability of the test.

[0060] This application also provides a method for preparing the above-mentioned probe card. This method is simple and controllable, and suitable for mass production. Specifically, it includes the following steps:

[0061] Step 1: Provide the required components such as PCB board 31, space conversion substrate 32, guide plate, multiple probes 333, flexible circuit board 5 and coaxial cable 6;

[0062] Step 2: Open multiple guide holes on the guide plate. Select at least one guide hole as the high-speed guide hole 4 according to the high-speed test requirements. Perform metallization process on the hole wall 41 of the high-speed guide hole 4 and the surface of the guide plate connected to it (e.g., the surface of the guide plate within 2mm around the high-speed guide hole 4) to form a metal plating layer 42.

[0063] Step 3: Fix the space conversion substrate 32 on the side of the PCB board 31 away from the test machine, so that the side of the PCB board 31 away from the test machine can be reliably electrically connected to the space conversion substrate 32 through internal wiring.

[0064] Step 4: Fix the guide plates parallel and spaced on the side of the space conversion base plate 32 away from the test machine to complete the basic assembly of the structural components;

[0065] Step 5: Pass multiple probes 333 through the guide holes on the guide plate, and connect and fix the probes 333 to the space conversion substrate 32, and ensure that the probes 333 in the high-speed guide hole 4 form a reliable sliding contact with the metal plating layer 42 of the hole wall 41.

[0066] Step 6: Connect and fix one end of the flexible circuit board 5 to the metal plating layer 42 around the high-speed guide hole 4, and connect and fix the other end of the flexible circuit board 5 to the PCB board 31 via the coaxial cable 6 to form a high-speed signal transmission channel.

[0067] Step 7: Complete the assembly and fixation of each component, check the reliability of each connection part, and ensure that there are no looseness, poor contact or other problems, and finally obtain the probe card.

[0068] In a further technical solution, prior to step 6 above, an impedance matching process is performed on the flexible circuit board. This impedance matching process can be achieved by adjusting parameters such as the line width, line spacing, and dielectric thickness of the flexible circuit board, so that the characteristic impedance of the flexible circuit board matches the requirements of high-speed signal transmission, effectively reducing reflection loss of high-speed signals during transmission on the flexible circuit board, and further improving signal transmission efficiency.

[0069] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes 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 probe card, wherein one side of the probe card is used for connection to a testing machine, and the other side is used for contacting a test point on a workpiece under test, characterized in that, The probe card includes structural components and high-speed signal transmission components; The structural components include a PCB board, a space conversion substrate, a guide plate, and multiple probes. One side of the PCB board is connected to a testing machine, and the other side is connected to the space conversion substrate via internal wiring. The space conversion substrate is located on the side of the PCB board facing away from the testing machine. The guide plates are arranged parallel to each other on the side of the space conversion substrate facing away from the testing machine, and multiple guide holes are formed on the guide plates. The probes pass through the corresponding guide holes and are connected to the PCB board via the space conversion substrate. The probes maintain sliding contact with the hole walls of the guide holes. At least one of the plurality of guide holes is a high-speed guide hole, and the surface of the hole wall of the high-speed guide hole and the guide plate portion connected thereto is formed with a metal plating layer by a metallization process. The high-speed signal transmission component includes a flexible circuit board and a coaxial cable; one end of the flexible circuit board is connected to the metal plating around the high-speed guide hole, and the other end is connected to the PCB board via the coaxial cable. The probe inside the high-speed guide hole makes sliding contact with the metal plating on the hole wall, and then connects to the PCB board via the flexible circuit board and coaxial cable to form a high-speed signal transmission channel. Other probes are connected to the PCB board via a space conversion substrate, forming a conventional signal transmission channel.

2. The probe card according to claim 1, characterized in that, The guide plate is provided in at least two pieces, and each guide plate is arranged parallel to each other at intervals. Each guide plate has a guide hole at a corresponding position, and the probe passes vertically through the guide hole on each guide plate.

3. The probe card according to claim 2, characterized in that, The high-speed guide hole is located on the guide plate closest to the part under test.

4. The probe card according to claim 3, characterized in that, The high-speed guide holes are provided in multiple locations and are located on the same guide plate.

5. The probe card according to claim 4, characterized in that, The distance between the metal plating layers corresponding to adjacent high-speed guide holes is not less than 0.5 mm.

6. The probe card according to claim 1, characterized in that, The guide plate is made of ceramic insulating material, and the metal plating layer is prepared by coating, photolithography and electroplating processes.

7. The probe card according to claim 1, characterized in that, The coaxial cable is wrapped with a metal shielding layer.

8. The probe card according to claim 1, characterized in that, The probe card structure assembly also includes a reinforcement structure, which is mounted on the side of the PCB board away from the probe and is used to reinforce the overall structure of the probe card.

9. A method for preparing a probe card as described in claim 1, characterized in that, Includes the following steps: Step 1: Provide PCB board, space conversion substrate, guide plate, multiple probes, flexible circuit board and coaxial cable; Step 2: Open multiple guide holes on the guide plate, select at least one guide hole as a high-speed guide hole, and perform a metallization process on the hole wall of the high-speed guide hole and the surface of the guide plate connected to it to form a metal plating layer. Step 3: Place the space conversion substrate on the side of the PCB board away from the test machine, and connect the side of the PCB board away from the test machine to the space conversion substrate through internal traces. Step 4: Place the guide plates parallel to each other on the side of the space conversion substrate away from the testing machine to complete the basic assembly of the structural components; Step 5: Pass multiple probes through the corresponding guide holes on the guide plate and connect them to the space conversion substrate, and the probes in the high-speed guide holes form a sliding contact with the metal plating on the hole wall; Step 6: Connect one end of the flexible circuit board to the metal plating around the high-speed guide hole, and connect the other end of the flexible circuit board to the PCB board via a coaxial cable to form a high-speed signal transmission channel. Step 7: Complete the assembly and fixation of each component to obtain the probe card.

10. The preparation method according to claim 9, characterized in that, Before step 6, the process also includes impedance matching of the flexible circuit board.

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