MEMS vertical probe card
By electroplating a circuit layer on the surface of the guide plate of the MEMS vertical probe card and adjusting the gap distance, the impedance adjustment problem in the high-density probe area was solved, which improved the electrical performance of high-speed signals and increased the test coverage, simplified the manufacturing process and reduced the cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- MAXONE SEMICON CO LTD
- Filing Date
- 2025-03-03
- Publication Date
- 2026-04-28
AI Technical Summary
Existing MEMS vertical probe cards are difficult to effectively adjust impedance in high-density probe areas, have complex structures and are prone to failure, affecting test coverage and assembly difficulty.
A circuit layer is electroplated on the surface of the probe card's guide plate, and the impedance is controlled by adjusting the gap between the circuit layer and the high-speed probe. Combined with the conductor filling and the electrical connection of the ground probe, the probe impedance can be precisely adjusted.
It improves the feasibility and coverage of high-speed wafer testing, simplifies the manufacturing process, and reduces costs.
Smart Images
Figure CN224176604U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of semiconductor chip testing technology, and in particular to a microelectromechanical system (MEMS) probe card. Background Technology
[0002] A probe card is an interface between the chip under test (DUT) and the testing machine in wafer testing. It is primarily used to perform preliminary measurements of the chip's electrical performance before chip slab packaging, and to screen out defective chips before proceeding with the subsequent packaging process. Therefore, it is a key tool for chip functional verification testing and industrialization testing.
[0003] With the development of Micro-Electro-Mechanical Systems (MEMS) technology, the industry's most advanced manufacturing processes have reached 3nm, and chip design scale is becoming increasingly larger. Some complex SoCs have achieved on-chip integration of up to 10 billion transistors. As chip complexity increases, the number of internal modules and manufacturing processes become more advanced, leading to a greater variety of failure modes. Therefore, the importance of effectively and completely testing the entire chip during the design process is growing. Furthermore, with the development of advanced packaging, back-end packaging costs are rising, placing increasingly higher demands on CP (Content Delivery) test coverage. Currently, CP test probe cards for SoCs can only support testing requirements of <10Gbps. There is an urgent need to develop high-speed MEMS probe cards.
[0004] Structurally, probe cards can be divided into two types: vertical probe cards, named for the perpendicularity of the probe to the substrate. A vertical probe card generally consists of three parts: a printed circuit board (PCB), a Space Transformer (MLO, MLC, or WST), and a probe head. The probe head of the vertical probe card comprises a first guide plate, a pad, a second guide plate, and the probe itself. The first and second guide plates are made of ceramic and are spaced apart. Holes are drilled in these plates using laser or mechanical drilling methods, and the probe is inserted into these holes.
[0005] To meet the testing requirements of high-speed transmission of the chip under test, the impedance of the probe needs to be adjusted. A representative structure can be found in utility model patent CN 111239449B, which discloses a solution where a flexible carrier board is added to the upper guide plate unit. A circuit layer is provided on this flexible carrier board, and an impedance adjustment component is connected to this circuit layer. The probe is electrically coupled to the impedance adjustment component through the circuit layer on the flexible carrier board, thus adjusting the probe's impedance. The impedance adjustment component described in this patent is exemplified as a capacitor assembly. While the solution disclosed in this patent can theoretically achieve control and adjustment of the probe impedance, the following problems still exist in practical applications:
[0006] 1. When the probe area is too large, there is no space to arrange the impedance adjustment component. The probe card is a precision component. If the guide plate area is too large, warping may occur, affecting the levelness of the guide plate. If there is warping, the assembly of the flexible carrier plate is basically impossible. Similarly, if the carrier plate area is controlled, there is not enough remaining space to arrange the impedance adjustment component when the probe area is large.
[0007] 2. The structure is too complex and difficult to implement. The structure requires the addition of a flexible carrier plate located between the upper and lower guide plate units. The probe card is a precision component. Based on different requirements, the typical probe spacing is 80~100um, and the smallest probe spacing can be about 50um. The dense probe planting area will increase the assembly difficulty. The addition of a flexible carrier plate will greatly increase the difficulty of probe matching and alignment and the process of inserting the probe into the probe hole.
[0008] 3. The impedance adjustment function is prone to failure. This device relies on the flexible carrier plate being partially separated from the guide plate when the probe is compressed. Since any processed part has processing deviations, when the probe is compressed, there may be matching problems caused by the probe size deviation, which may prevent the flexible carrier plate from being effectively separated. Summary of the Invention
[0009] The purpose of this invention is to provide a MEMS vertical probe card to achieve probe impedance control at low cost.
[0010] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a MEMS vertical probe card, comprising a probe card head, the probe card head including a first guide plate, a second guide plate, and probes; the first guide plate and the second guide plate are spaced apart, and through holes are formed on the first guide plate and the second guide plate, the probes passing through the through holes of the first guide plate and the second guide plate; the probes include grounding probes and signal probes; at least one of the signal probes is a high-speed probe; the surfaces of the first guide plate and the second guide plate facing each other are defined as inner surfaces, and their opposite surfaces are defined as outer surfaces; at least one of the four surfaces of the first guide plate, the first guide plate, the second guide plate, and the second guide plate has a circuit layer electroplated on it, the circuit layer having a grounding area extending to the side of the high-speed probe, with a gap distance between it and the high-speed probe for determining impedance, the impedance of the high-speed probe can be adjusted by adjusting the gap distance.
[0011] In the above scheme, "the outer surface of the first guide plate, the inner surface of the first guide plate, the outer surface of the second guide plate, and the inner surface of the second guide plate" are explained as follows: the surface of the first guide plate facing the second guide plate is defined as the inner surface, and the opposite surface is the outer surface; similarly, the surface of the second guide plate facing the first guide plate is defined as the inner surface, and the opposite surface is the outer surface.
[0012] In the above scheme, a hole is drilled next to the high-speed probe on the ground surface of the grounding area, and a conductor is filled or electroplated in the hole.
[0013] In the above scheme, the grounding area extends into the through hole of the grounding probe with an inner electroplated layer. The inner electroplated layer contacts the grounding probe inside the hole to form an electrical connection, that is, the grounding area is grounded through the grounding probe.
[0014] In the above scheme, the circuit layer is electroplated on the outer surface of the first guide plate, the inner surface of the first guide plate, the outer surface of the second guide plate, and the inner surface of the second guide plate, so that the two ends of the high-speed probe are impedance controlled.
[0015] In the above scheme, the first guide plate and the second guide plate are fixedly separated by a hollowed-out structural component, i.e., the first guide plate is the upper guide plate and the second guide plate is the lower guide plate. Furthermore, depending on the probe length and structure, the upper guide plate can be configured as a single layer or multiple layers, and the lower guide plate can also be configured as a single layer or multiple layers.
[0016] In the above scheme, the electrical property of the line layer is GND, which is used as a reference for impedance control. The gap distance A between the line layer and the probe can be determined by simulation using electrical performance simulation software.
[0017] This utility model has the following advantages:
[0018] This invention improves the electrical performance of high-speed signals by controlling and adjusting the gap distance A between the ground plane and the high-speed probe on the circuit layer, thereby enhancing the feasibility of high-speed wafer testing and increasing test coverage. Furthermore, this invention is very easy to manufacture; it only requires adding an electroplating process to the existing conventional first and second guide plate manufacturing processes to complete the circuit layer fabrication. The cost is not high, making it highly practical. Attached Figure Description
[0019] Figure 1 This is a cross-sectional schematic diagram of the probe card head according to an embodiment of the present utility model;
[0020] Figure 2 This is a partial three-dimensional schematic diagram of the needle implantation area of the probe card head according to an embodiment of the present invention. Only the needle implantation areas of the first guide plate and the second guide plate are shown in the figure, and the pad is not shown.
[0021] Figure 3 for Figure 2 A magnified schematic diagram of a portion of the outer surface of the first guide plate.
[0022] In the above figure: 1. Probe card head; 11. First guide plate; 12. Second guide plate; 13. Pad; 14. Probe; 141. Grounding probe; 142. Signal probe; 1421. High-speed probe; 15. Line layer; 151. Grounding area; 1511. Conductor; A. Gap distance. Detailed Implementation
[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments:
[0024] See the example. Figure 1-3 As shown:
[0025] A MEMS vertical probe card includes a printed circuit board, a space converter, and a probe card head 1.
[0026] like Figure 1 As shown, the probe card head 1 includes a first guide plate 11, a second guide plate 12, a pad 13, and a probe 14. The first guide plate 11 and the second guide plate 12 are spaced apart, and through holes are formed on the first guide plate 11 and the second guide plate 12. The probe passes through the through holes of the first guide plate 11 and the second guide plate 12.
[0027] See Figure 2As shown, the probes include a ground probe 141 and a signal probe 142; at least one of the signal probes 142 serves as a high-speed probe 1421. The specific number and arrangement of the ground probes 141 and signal probes 142 need to be selected according to the different chips under test, therefore the specific number and arrangement are not limited. The specific number of signal probes 142 that serve as high-speed probes also needs to be adjusted and determined according to actual requirements. Figure 2 The example uses two signal probes as high-speed probes.
[0028] See Figures 1-3 As shown, the surfaces of the first guide plate (11) and the second guide plate (12) facing each other are defined as inner surfaces, and their opposite surfaces are defined as outer surfaces. At least one of the four surfaces of the first guide plate 11, the first guide plate 11, the second guide plate 12, and the second guide plate 12 is plated with a circuit layer 15. The circuit layer 15 has a grounding area 151 that extends to the side of the high-speed probe 1421. A gap distance A is left between the high-speed probe 1421 and the high-speed probe 1421 to determine the impedance. Adjusting the gap distance A can adjust the impedance of the high-speed probe 1421.
[0029] See Figure 3 As shown, a hole is drilled next to the high-speed probe 1421 on the contact area 151, and a conductor 1511 is filled or electroplated in the hole to increase the area of the conductor close to the high-speed probe 1421.
[0030] The grounding area 151 extends into the through-hole of the grounding probe 141, forming an internal electroplated layer. This internal electroplated layer contacts the grounding probe 141 inside the hole, thus forming an electrical connection. That is, the grounding area 151 is grounded through the grounding probe 141. This is one method of grounding the grounding area. Of course, the grounding area 151 can also extend to the edge of the guide plate and be grounded by other wires.
[0031] like Figure 1 and Figure 2 As shown, the first guide plate 11 and the second layer plate 12 are fixedly separated by a pad 13, that is, the first guide plate 11 is the upper guide plate and the second guide plate 12 is the lower guide plate. The pad 13 is a type of hollow structure that fixes the first guide plate 11 and the second guide plate 12. In practice, other types of hollow structures can also be used.
[0032] Specifically, depending on the probe length and structure, the upper guide plate can be set as a single-layer structure or a multi-layer structure, and the lower guide plate can also be set as a single-layer or multi-layer structure.
[0033] In this embodiment, it is preferable to electroplate the circuit layer 15 on the outer surface of the first guide plate 11, the inner surface of the first guide plate 11, the outer surface of the second guide plate 12, and the inner surface of the second guide plate 12, so that both ends of the high-speed probe 1421 have impedance control.
[0034] This embodiment achieves impedance control of the signal probe by controlling and adjusting the distance between the ground area 151 on the circuit layer 15 and the high-speed probe 1421, thereby improving the electrical performance of the high-speed signal, enhancing the feasibility of high-speed wafer testing, and increasing test coverage.
[0035] Furthermore, the manufacturing process is very convenient. It only requires adding an electroplating process to the existing conventional manufacturing processes of the first guide plate 11 and the second guide plate 12 to complete the circuit layer fabrication. The manufacturing method is as follows:
[0036] A. Machining the conventional first guide plate 11 and second guide plate 12;
[0037] B. Determine the structure of line layer 15 by matching simulated signals (mainly determining the gap distance A), and use electroplating process to achieve coverage of the grounding area 151;
[0038] C. Assemble the probes to complete the fabrication of the probe card head.
[0039] This embodiment is inexpensive to implement and has great practical value.
[0040] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.
Claims
1. A MEMS vertical probe card, comprising a probe card head (1), the probe card head (1) comprising a first guide plate (11), a second guide plate (12), and a probe (14); the first guide plate (11) and the second guide plate (12) are disposed apart, and through holes are formed on the first guide plate (11) and the second guide plate (12), the probe being disposed through the through holes of the first guide plate (11) and the second guide plate (12); the probe comprises a grounding probe (141) and a signal probe (142); at least one of the signal probes (142) serves as a high-speed probe (1421); characterized in that: The surfaces opposite to the first guide plate (11) and the second guide plate (12) are defined as inner surfaces, and the surfaces opposite to each other are defined as outer surfaces. At least one of the four surfaces of the first guide plate (11), the first guide plate (11), the second guide plate (12), and the second guide plate (12) is plated with a circuit layer (15). The circuit layer (15) has a grounding area (151) that extends to the side of the high-speed probe (1421) and is separated from the high-speed probe (1421) by a gap distance (A) for determining the impedance. Adjusting the gap distance (A) can adjust the impedance of the high-speed probe (1421).
2. The MEMS vertical probe card according to claim 1, characterized in that: A hole is drilled next to the high-speed probe (1421) on the grounding area (151), and a conductor (1511) is filled or electroplated in the hole.
3. The MEMS vertical probe card according to claim 1, characterized in that: The grounding area (151) extends into the through hole of the grounding probe (141) with an inner electroplated layer. The inner electroplated layer contacts the grounding probe (141) in the hole to form an electrical connection, that is, the grounding area (151) is grounded through the grounding probe (141).
4. The MEMS vertical probe card according to claim 1, characterized in that: The circuit layer (15) is electroplated on the outer surface of the first guide plate (11), the inner surface of the first guide plate (11), the outer surface of the second guide plate (12), and the inner surface of the second guide plate (12), so that the two ends of the high-speed probe (1421) are impedance controlled.
5. The MEMS vertical probe card according to any one of claims 1-3, characterized in that: The first guide plate and the second layer plate are fixedly separated by a hollowed-out structural component, that is, the first guide plate is the upper guide plate and the second guide plate is the lower guide plate.
6. The MEMS vertical probe card according to claim 5, characterized in that: Depending on the probe length and structure, the upper guide plate is configured as a single layer or multiple layers, and the lower guide plate is also configured as a single layer or multiple layers.