MEMS vertical probe card
By electroplating the circuit layer on the guide plate of the MEMS probe card and adjusting the probe gap distance, the problem of difficulty in impedance adjustment of existing probe cards under high-speed tests is solved, and efficient high-speed signal testing and improved test coverage are achieved.
Patent Information
- Application Number
- CN202510239598.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-03
- Publication Date
- 2025-04-18
AI Technical Summary
Existing MEMS probe cards are difficult to achieve effective impedance adjustment under the requirements of high-speed testing, resulting in complex structure, difficult assembly and easy failure of impedance adjustment functions.
By electroplating the circuit layer on the first and second guides and setting the gap distance A next to the high-speed probe, the gap distance is adjusted to control the impedance of the probe.
It has achieved the improvement of electrical performance of high-speed signals, improved the high-speed test achievability and test coverage of wafer tests, and has low production cost and high practical value.
Smart Images
Figure CN119846280A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor chip testing, and in particular to a micro-electromechanical system (MEMS) probe card. Background Art
[0002] The probe card is the interface between the chip under test and the tester in wafer test. It is mainly used to make preliminary measurements of the chip electrical performance before chip segmentation and packaging, and to screen out defective chips before subsequent packaging. Therefore, it is a key tool for chip function verification testing and industrial testing.
[0003] With the development of micro-electro-mechanical system (MEMS) technology, the industry's most advanced manufacturing process has entered 3nm, and the scale of chip design is getting larger and larger. The on-chip integration of some complex SOCs has reached the level of 10 billion transistors. As the complexity of chips increases, there are more and more modules inside the chip, and the manufacturing process is becoming more and more advanced. The corresponding failure modes are increasing, and how to fully and effectively test the entire chip has become more and more important in the design process. With the development of advanced packaging, the cost of back-end packaging is getting higher and higher, and the CP test coverage rate has also been put forward. Higher and higher requirements are also put forward. At present, the CP test probe card for SOC can only support the test requirements of <10Gbps. Now it is urgent to develop a high-speed MEMS probe card.
[0004] There are two types of probe cards, one is a vertical probe card, which is named because the probe needle is perpendicular to the substrate. A vertical probe card is generally composed of the following three parts: a printed circuit board (PCB), a Space Transformer (MLO or MLC or WST) and a Probe Head. The probe head of the vertical probe card is composed of a first guide plate, a pad, a second guide plate and a probe, wherein the first guide plate and the second guide plate are ceramic structures and are set apart, and holes are drilled on them using laser or mechanical drilling methods, and the probes are inserted into the holes.
[0005] In order to meet the test requirements of high-speed transmission of the chip to be tested, it is necessary to adjust the impedance of the probe. For a representative structure, please refer to the utility model patent CN 111239449B. The solution disclosed in it is: add a flexible carrier plate in the upper guide plate unit, set a circuit layer on the flexible carrier plate, and connect an impedance adjustment member to the circuit layer, so that the probe is electrically coupled to the impedance adjustment member through the circuit layer on the flexible carrier plate, that is, the impedance of the probe is adjusted by the impedance adjustment member. The impedance adjustment member described in the patent is exemplified as a capacitor component. The solution disclosed in the patent can theoretically realize the control and adjustment of the probe impedance, but there are still the following problems in practical applications: 1. When the probe area is too large, there is no space to arrange the impedance adjuster. The probe card is a precision component. If the guide plate area is too large, it will be warped and affect the levelness of the guide plate. In the case of warping, the assembly of the flexible carrier is basically impossible. Similarly, if the carrier area is controlled, when the probe area is large, there will not be enough remaining space to arrange the impedance adjuster. 2. The structure is too complex and difficult to implement. The structure requires the addition of a flexible carrier plate, which is located between the upper and lower guide plate units. The probe card is a structural precision component. Based on different requirements, the typical probe spacing is 80~100um, and the minimum probe spacing can be around 50um. The dense probe implantation area will increase the difficulty of assembly. The additional 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 pinhole; 3. The impedance adjustment function is prone to failure. The device relies on the partial separation of the flexible carrier from the guide plate when the probe is compressed. Since any processed parts have processing deviations, there may be matching problems caused by the probe size deviation when the probe is compressed, resulting in the inability to effectively separate the flexible carrier. Summary of the invention
[0006] The object of the present invention is to provide a MEMS vertical probe card to achieve control of probe impedance at low cost.
[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a MEMS vertical probe card, comprising a probe card head, the probe card head comprising a first guide plate, a second guide plate and a probe; the first guide plate and the second guide plate are arranged at a distance, through holes are provided on the first guide plate and the second guide plate, and the probe passes through the through holes of the first guide plate and the second guide plate; the probe comprises a grounding probe and a signal probe; at least one of the signal probes is used as a high-speed probe; The surfaces opposite to each other of the first guide plate and the second guide plate are defined as inner surfaces, and the surfaces opposite to each other are defined as outer surfaces; at least one of 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 is plated with a circuit layer, and the circuit layer has a grounding area for grounding, and the grounding area extends to the side of the high-speed probe, leaving a gap distance between the high-speed probe and the high-speed probe for determining impedance, and adjusting the gap distance can adjust the impedance of the high-speed probe.
[0008] 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 side surface of the first guide plate facing the second guide plate is defined as the inner surface, and the other side surface opposite to it is the outer surface; similarly, the side surface of the second guide plate facing the first guide plate is defined as the inner surface, and the other side surface opposite to it is the outer surface.
[0009] In the above solution, a hole is drilled on the grounding area next to the high-speed probe, and a conductor is filled or electroplated in the hole.
[0010] In the above solution, the grounding region extends an in-hole electroplating layer into the through hole of the grounding probe, and the in-hole electroplating layer contacts the grounding probe in the hole to form an electrical connection, that is, the grounding region is grounded through the grounding probe.
[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 all plated with the circuit layer, so that both ends of the high-speed probe have impedance control.
[0012] In the above scheme, the first guide plate and the second layer plate are fixedly separated and arranged up and down by a hollow structure in the middle, that is, the first guide plate is an upper guide plate, and the second guide plate is a lower guide plate. Further, according to the length and structure of the probe, the upper guide plate is set to be a single layer or a multi-layer structure, and the lower layer plate is also set to be a single layer or a multi-layer structure.
[0013] In the above solution, the electrical property of the circuit layer is GND, which is used as a reference for impedance control. The gap distance A between the circuit layer and the probe can be simulated and determined using electrical performance simulation tool software.
[0014] The present invention has the following advantages: The present invention improves the electrical performance of high-speed signals by controlling and adjusting the gap distance A between the grounding area on the circuit layer and the high-speed probe, thereby improving the feasibility of high-speed testing of wafer tests and improving the test coverage. In addition, the present invention is very convenient to manufacture and implement, and only one step of electroplating process is added to the existing conventional manufacturing process of the first guide plate and the second guide plate to complete the manufacturing of the circuit layer, which is not costly and has great practical value. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 is a cross-sectional schematic diagram of a probe card head according to an embodiment of the present invention; Figure 2 It 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, in which only the needle implantation areas of the first guide plate and the second guide plate are intercepted, and the pad is not shown; Figure 3 for Figure 2 A partial enlarged schematic diagram of the outer surface of the first guide plate.
[0016] In the above figure: 1. probe card head; 11. first guide plate; 12. second guide plate; 13. pad; 14. probe; 141. ground probe; 142. signal probe; 1421. high-speed probe; 15. circuit layer; 151. ground area; 1511. conductor; A. gap distance. DETAILED DESCRIPTION
[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: For example, see Figure 1-3 As shown, A MEMS vertical probe card comprises a printed circuit board, a space transformer and a probe card head 1.
[0018] 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 arranged at a distance, and through holes are provided on the first guide plate 11 and the second guide plate 12, and the probe passes through the through holes of the first guide plate 11 and the second guide plate 12.
[0019] See also Figure 2 As shown, the probe includes a ground probe 141 and a signal probe 142; at least one of the signal probes 142 is used as a high-speed probe 1421. The number and arrangement of the specific ground probes 141 and signal probes 142 need to be selected according to the different chips to be tested, so the specific number and arrangement structure are not limited. The specific number of signal probes 142 used as high-speed probes also needs to be adjusted and determined according to actual needs. Figure 2 Two signal probes are used as high-speed probes.
[0020] See also Figure 1-Figure 3As shown, the surfaces opposite to each other of 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 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 is electroplated with a circuit layer 15, and the circuit layer 15 has a grounding area 151 for grounding, and the grounding area 151 extends to the side of the high-speed probe 1421, and a gap distance A for determining impedance is left between the grounding area 151 and the high-speed probe 1421, and the impedance of the high-speed probe 142 can be adjusted by adjusting the gap distance A.
[0021] See also Figure 3 As shown, a hole is punched on the grounding area 151 next to the high-speed probe 141 , and a conductor 1511 is filled or electroplated in the hole to increase the area of the conductor close to the high-speed probe 141 .
[0022] The grounding region 151 extends an in-hole electroplating layer into the through hole of the grounding probe 141, and the in-hole electroplating layer contacts the grounding probe 141 in the hole to form an electrical connection, that is, the grounding region 151 is grounded through the grounding probe 141. This is one way of grounding the grounding region, and of course the grounding region 151 can also extend to the edge of the guide plate to be grounded by other wires.
[0023] like Figure 1 and Figure 2 As shown, the first guide plate 11 and the second layer plate 12 are fixedly separated and arranged up and down by the pad 13, that is, the first guide plate 11 is an upper guide plate, and the second guide plate 12 is a lower guide plate. The pad 13 is a hollow structure for fixing the first guide plate 11 and the second guide plate 12. In practice, other hollow structures can also be used.
[0024] Specifically, according to the length and structure of the probe, the upper guide plate can be set to a single-layer structure or a multi-layer structure, and the lower plate can also be set to a single-layer or multi-layer structure.
[0025] In this embodiment, it is preferred 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.
[0026] This embodiment can control the impedance of the signal probe by controlling 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, thereby improving the feasibility of high-speed wafer testing and improving test coverage.
[0027] Moreover, the manufacturing is very convenient. It is only necessary to add a step of electroplating process to the conventional manufacturing process of the first guide plate 11 and the second guide plate 12 to complete the manufacturing of the circuit layer. The manufacturing method is as follows: A. Processing the conventional first guide plate 11 and the second guide plate 12; B. Determine the structure of the circuit layer 15 (mainly determine the gap distance A) by matching the simulation signal, and use the electroplating process to achieve coverage of the grounding area 151; C. Assemble the probes and complete the production of the probe card head.
[0028] The implementation cost of this embodiment is not high and is very practical.
[0029] The above 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 changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.
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 arranged at a distance from each other, through holes are provided on the first guide plate (11) and the second guide plate (12), and the probe is arranged 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) is used as a high-speed probe (1421); the characteristics are: The surfaces opposite to each other of 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 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) is electroplated with a circuit layer (15), the circuit layer (15) having a grounding area (151) for grounding, the grounding area (151) extending to the side of the high-speed probe (1421), leaving a gap distance (A) between the grounding area (151) and the high-speed probe (1421) for determining impedance, and the impedance of the high-speed probe (142) can be adjusted by adjusting the gap distance (A).
2. The MEMS vertical probe card according to claim 1, characterized in that: A hole is punched on the grounding area (151) next to the high-speed probe (141), 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 region (151) extends an in-hole electroplating layer into the through hole of the grounding probe (141), and the in-hole electroplating layer contacts the grounding probe (141) in the hole to form an electrical connection, that is, the grounding region (151) is grounded via 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 both ends of the high-speed probe (1421) have impedance control.
5. The MEMS vertical probe card according to any one of claims 1 to 3, characterized in that: The first guide plate and the second layer plate are fixedly separated and arranged up and down by a hollow structure in the middle, that is, the first guide plate is an upper guide plate, and the second guide plate is a lower guide plate.
6. The MEMS vertical probe card according to claim 5, characterized in that: According to the length and structure of the probe, the upper guide plate is configured to be a single layer or a multi-layer structure, and the lower plate is also configured to be a single layer or a multi-layer structure.