MEMS elastic probe and MEMS elastic probe card for collaborative test before co-packaging

Abstract

The invention discloses an MEMS (Micro Electro Mechanical System) elastic probe for a collaborative test before co-packaging, which has electrical conductivity on the whole and comprises an elastic main body and a salient point arranged at the upper end of the elastic main body, and when the salient points are pressed, the elastic main body can adaptively and elastically deform. The invention aims to provide the interposer MEMS spring probe for the HBM test, which has the advantages of stable connection signal and lossless and detachable connection.

Description

Technical Field

[0001] The present invention belongs to the technical field of chip testing equipment, and in particular relates to a MEMS elastic probe used for collaborative testing of 2.5D or 3D co-sealed chips such as HBM and GPU before co-sealing, and an elastic probe card including the MEMS elastic probe. Background Art

[0002] Advanced Packaging (AP), also known as high-density packaging, significantly improves chip performance by reducing I / O spacing and interconnect length, increasing I / O density. Compared with traditional packaging, advanced packaging has higher memory bandwidth, better energy efficiency, stronger performance and thinner chip thickness, and can achieve multi-chip integration, heterogeneous integration and high-speed interconnection between chips. Bump, RDL (rewiring layer), TSV (through silicon via) and HybridBonding are the core technologies supporting advanced packaging.

[0003] Back-end testing is the final inspection step after semiconductor packaging, which verifies the electrical performance and reliability of the chip after physical packaging to ensure that the product meets factory standards.

[0004] The HBM (High Bandwidth Memory) test is divided into two stages: standalone test and co-test with GPU / CPU, corresponding to different manufacturing nodes and targets respectively.

[0005] In the independent test of HBM particles, only HBM itself is tested, and its synergistic performance with GPU / CPU cannot be evaluated, so it is difficult to simulate the real application environment. The test results only reflect the independent performance of HBM, not its final performance after being co-sealed with GPU / CPU. In the traditional co-test (Co-Test with GPU / CPU) stage, HBM is usually physically integrated with GPU / CPU through Interposer, and the specific packaging form depends on the technical route (such as 2.5D silicon interposer or 3D hybrid bonding). At this time, the chip has been packaged. If problems are found in the performance or quality of HBM or GPU / CPU, no modifications can be made to the packaged chip. Therefore, if the co-test fails, it will result in joint losses of HBM, GPU and Interposer (the cost of a single module exceeds $10k), which highlights the necessity of strict pre-initiated independent testing.

[0006] Figure 1 The traditional 2.5D packaging structure is shown. Figure 2This is the basic structure of a common co-packaged chip with HBM particles 12 and GPU / CPU particles 13. Multiple chips under test 1 achieve horizontal communication between the chips under test through the plug-in layer 14, and at the same time achieve vertical communication between the chips under test and the packaging substrate through the plug-in layer.

[0007] As Figure 1 , 2 shown, the microbumps on the plug-in layer are used for flip-chip soldering of the chips, welding the chips under test (such as HBM particles 12, GPU / CPU particles 13, etc.) to the plug-in layer 14, and welding the plug-in layer 14 to the packaging substrate 15 to ensure the reliability of electrical signal transmission. Once the bumps between the chips under test 1 and the plug-in layer 14 are welded, it is difficult to remove the chips under test, otherwise it may cause permanent physical damage to the chips under test, the plug-in layer or other layers. Therefore, this method is only applicable to final packaging, rather than temporary testing before packaging. Summary of the Invention

[0008] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide an interposer MEMS spring probe for HBM testing with stable connection signals and non-destructive detachable connection.

[0009] The solution of this application provides a MEMS elastic probe for co-testing before co-packaging, which is conductive as a whole and includes: an elastic main body and bumps arranged at the upper end of the elastic main body; when the bumps are pressed, the elastic main body can adaptively elastically deform.

[0010] The elastic main body is one or more of a bending-type elastic component, a compression / tension-type elastic component, or a composite deformation-type elastic component.

[0011] The elastic main body is a bending-type elastic component, including multiple groups of stepped and misaligned stacked metal reed pieces. While adjacent reed pieces form a height difference in the vertical direction, they maintain a preset interval or are staggered in the horizontal direction.

[0012] The reed pieces are straight reed pieces or arc-shaped reed pieces.

[0013] The elastic main body is a helical spring structure in the compression / tension-type elastic component.

[0014] The bumps are hemispherical, or needle-shaped with multi-sided edges, or conical.

[0015] A MEMS elastic probe card for co-testing before co-packaging includes an interposer and the MEMS elastic probe described above; the interposer includes a plurality of electrical connection points respectively arranged on the upper and lower end faces, and vertical electrical channels and / or horizontal electrical channels connecting two or more electrical connection points; the MEMS elastic probe is arranged on the upper end face of the interposer, and its lower end is connected to at least one electrical connection point.

[0016] The improvements of the present application bring the following advantages: The MEMS elastic probe and the elastic probe card for pre - co - packaging collaborative testing provided by the embodiments of the present application are convenient to use. Only by aligning and pressing the chip to be tested onto the spring probe can a temporary connection be established, and the connection signal is stable. After the test is completed, only by withdrawing the pressure on the chip to be tested can the chip to be tested be removed without damage, and the test is convenient and low - cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Shows a traditional 2.5D packaging structure;

[0018] Figure 2 Is the basic structure of a common co - packaged chip of HBM and GPU / CPU;

[0019] Figure 3 Is a schematic cross - sectional structure diagram of the interposer of the MEMS elastic probe card according to the embodiment of the present application;

[0020] Figure 4 Is a schematic three - dimensional structure diagram of a MEMS elastic probe card for pre - co - packaging collaborative testing according to the embodiment of the present application;

[0021] Figure 5 Is a schematic side - view structure diagram of a MEMS elastic probe card for pre - co - packaging collaborative testing according to the embodiment of the present application;

[0022] Figure 6 Is a schematic three - dimensional structure diagram of a MEMS elastic probe for pre - co - packaging collaborative testing according to the embodiment of the present application;

[0023] Figure 7 Is a schematic diagram of the usage state of a MEMS elastic probe card for pre - co - packaging collaborative testing according to the embodiment of the present application;

[0024] Figure 8 Is another schematic diagram of the usage state of a MEMS elastic probe card for pre - co - packaging collaborative testing according to the embodiment of the present application;

[0025] Figure 9 Is another schematic diagram of the usage state of a MEMS elastic probe card for pre - co - packaging collaborative testing according to the embodiment of the present application;

[0026] Among them, chip to be tested - 1; HBM particle - 12; GPU / CPU particle - 13; plug - in layer - 14; packaging substrate - 15; interposer - 2; electrical connection point - 21; vertical electrical channel - 22; horizontal electrical channel - 23; MEMS elastic probe - 3; elastic main body - 31; bump - 32; reed - 33. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0028] As described above, the characteristics of the bumps on the plug-in layer (the connection can only be a permanent connection and cannot be disconnected without damage) make it crucial in "temporary" tests such as SLT, ATE, or probe stations whether the device under test (DUT), such as GPU / CPU, HBM particles, GDDR particles, can establish a good and temporary electrical signal connection with the PCB of the tester: the electrical signal must be stably connected, and the connection method needs to be temporary and non-destructive.

[0029] Please refer to Figure 3-9 , an MEMS elastic probe card for co-packaging pre-cooperative testing according to an embodiment of the present application includes an interposer 2 and MEMS elastic probes 3 disposed on the upper end face of the interposer 2.

[0030] The interposer 2 includes a plurality of electrical connection points 21 respectively disposed on the upper and lower end faces, and vertical electrical channels 22 and / or horizontal electrical channels 23 connecting two or more electrical connection points 21. Communication between chips is carried out through the horizontal electrical channel 23, and communication between the chip and the packaging substrate 15 is carried out through the vertical electrical channel 22.

[0031] The entire MEMS elastic probe 3 has conductivity, including an elastic body 31 and a bump 32 disposed on the upper end of the elastic body 31; when the bump 32 is pressed, the elastic body 31 can adaptively elastically deform.

[0032] MEMS, Micro-Electro-Mechanical System.

[0033] In the present application, the interposer 2 is at the bottom and the MEMS elastic probe 3 is at the top.

[0034] The MEMS elastic probe 3 and the MEMS elastic probe card provided by the embodiment of the present application are convenient to use. Only need to align and press the chip to be tested 1 onto the elastic probe to establish a temporary connection, and the connection signal is stable; after the test is completed, only need to withdraw the pressure on the chip to be tested 1, and the chip to be tested 1 can be removed without damage, and the test is convenient and the cost is low.

[0035] The usage method and technical principle of this embodiment are as follows: As Figure 7-9As shown, the MEMS elastic probe card 3 is set on the packaging substrate 15 and connected and communicates with the packaging substrate 15 through the electrical connection points 21 on its lower end surface to ensure good electrical signals for the connection. Then, the chip under test 1 is pressed onto the MEMS elastic probes 3 at the upper end of the MEMS elastic probe card 3 and temporarily connected and communicates with the chip under test 1 through the bumps 32 provided thereon to ensure good electrical signals for the connection. Since the elastic body 31 can adaptively elastically deform when the bump 32 is pressed, the interaction between the pressure and the resilience ensures that the bump 32 can closely fit the chip under test 1, ensuring good electrical signals for the connection between the two, and yet the chip under test 1 can be removed without damage after the test.

[0036] The elastic body 31 is one or more of a bending-type elastic component, a compression / tension-type elastic component, or a composite deformation-type elastic component.

[0037] The bending-type elastic component can include leaf springs, cantilever beams, elastic hinges, etc.; the compression / tension-type elastic component can include disc springs, bellows, elastic gaskets, etc.; the composite deformation-type elastic component can include grid springs, porous elastomers, etc. In addition, the elastic component can also be any other structure that can adaptively elastically deform when the bump 32 is pressed.

[0038] As Figure 6 shown, the bending-type elastic component includes multiple groups of stepped and misaligned stacked metal reed pieces 33. While adjacent reed pieces form a height difference in the vertical direction, they maintain a preset interval or are staggered in the horizontal direction.

[0039] Specifically, each layer of reed pieces is connected in series in a head-to-tail hinged manner (the head of the second layer is fixedly connected to the tail of the first layer, the head of the third layer is fixedly connected to the tail of the second layer, and so on), and a non-contact elastic buffer zone is reserved between adjacent reed pieces - through lateral misalignment layout or longitudinal gap design, ensuring that each reed piece can independently generate a progressive bending deformation when vertically pressed, while avoiding interlayer friction loss. The length of the reed piece decreases with the gradient of the layer height. Combining with the deformation redundancy space formed by the gap, the pressure is decomposed step by step along the layers, realizing the linear regulation of the stress-strain curve. This structure significantly improves the freedom degree of elastic deformation and the energy absorption efficiency through the gap buffer and misalignment synergistic effect, while the high yield strength characteristic of the metal material effectively inhibits the accumulation of plastic deformation.

[0040] The reed piece can be a straight reed piece or an arc-shaped reed piece.

[0041] The compression / tension-type elastic component can be a helical spring structure.

[0042] The material of the MEMS elastic probe 3 can be common MEMS probe materials, such as beryllium copper, brass or stainless steel, or carbon materials, or conductive materials coated with nickel-gold plating, etc. It has excellent electrical signal and chemical stability and is not easily oxidized. These MEMS elastic probes 3 can be processed by traditional surface micromachining methods such as photolithography-etching, or bulk micromachining, or LIGA technology (lithography, electroplating, injection molding), or SOI (silicon-on-insulator) technology.

[0043] The MEMS elastic probe 3 can be directly grown at the required position on the interposer 2, or its lower end can be permanently welded to the corresponding bumps 32 on the upper surface of the interposer 2. The upper surface of the interposer 2 contains these MEMS elastic probes 3, and vertical TSV conductive wires (vertical electrical channels 22 and horizontal electrical channels 23) are included in the middle to connect the bumps 32 and MEMS elastic probes 3 on its upper and lower surfaces and other chips 1 to be measured arranged horizontally.

[0044] The HBM can be a chip particle to be measured, while the GPU / CPU can be a non-chip particle to be measured;

[0045] The GPU / CPU can be a chip particle to be measured, while the HBM can be a non-chip particle to be measured;

[0046] One or several HBMs can be chip particles to be measured, while the remaining HBM particles and GPU / CPUs can be non-chip particles to be measured;

[0047] One or several GPU / CPUs can be chip particles to be measured, while the remaining GPU / CPUs and HBM particles can be non-chip particles to be measured;

[0048] One or several GPU / CPUs mixed with one or several HBMs can all be chip particles to be measured, while the remaining GPU / CPUs, HBM particles or other types of particles can be non-chip particles to be measured;

[0049] The HBM and GPU / CPU can both be chip particles to be measured, or there are no other chip particles as non-chip particles to be measured;

[0050] The chip particles listed above are not limited to common chip particles such as HBM / GDDR / GPU / CPU / XPU / GPO / CPO, etc.

[0051] As described above, it is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A MEMS elastic probe for collaborative testing before co-sealing, characterized in that: The whole body is conductive, and comprises an elastic body and a convex point arranged on the upper end of the elastic body; when the convex point is pressed, the elastic body can adaptively deform elastically.

2. The MEMS elastic probe according to claim 1, characterized in that: The elastic body is one or more of a bending type elastic component, a compression / tension type elastic component or a compound deformation type elastic component.

3. The MEMS elastic probe according to claim 2, characterized in that: The elastic body is a curved elastic component, comprising a plurality of groups of metal springs stacked in a stepped staggered manner. Adjacent springs form a layer height difference in the vertical direction while maintaining a preset interval or staggered distribution in the horizontal direction.

4. The MEMS elastic probe according to claim 3, characterized in that: The reed is a straight reed or an arc-shaped reed.

5. The MEMS elastic probe according to claim 2, characterized in that: The elastic body is a helical spring structure in a compression / tension type elastic component.

6. The MEMS elastic probe according to claim 1, characterized in that: The convex point is in a hemispherical shape, a polygonal needle shape, or a conical shape.

7. A MEMS elastic probe card for collaborative testing before co-sealing, characterized in that: It comprises an interposer and the MEMS elastic probe according to any one of claims 1 to 6; the interposer comprises a plurality of electrical connection points respectively arranged on the upper and lower end surfaces, and a vertical electrical channel and / or a horizontal electrical channel connecting two or more electrical connection points; the MEMS elastic probe is arranged on the upper end surface of the interposer, and its lower end is connected to at least one electrical connection point.

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