Test pattern monitoring method for MEMS probe card manufacturing process
By integrating dedicated test patterns onto a photomask, the problem of difficulty in quantifying process parameters during MEMS probe card manufacturing is solved, enabling real-time quality control and data-driven optimization of the process, thereby improving yield and reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-03-31
AI Technical Summary
Existing technologies lack effective online monitoring methods, which makes it impossible to quantify the status of process parameters in a timely and accurate manner during the manufacturing process of MEMS probe cards. This leads to a decrease in yield and reliability risks. Furthermore, process adjustments rely on experience, making it difficult to achieve precise data-driven optimization.
Multiple specialized test patterns are integrated on the mask to simultaneously form the functional structure and physical test structure of the MEMS probe. By measuring these test patterns, process quality parameter data are obtained and compared with preset thresholds to achieve process status evaluation and feedback adjustment.
It enables quantitative measurement of key indicators such as film thickness, contact resistance, interconnect performance, device basic parameters and defect density, ensuring improved product yield, MEMS probe reliability and assembly bonding yield.
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Figure CN121762894A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of probe card technology, and more specifically to a test pattern monitoring method for MEMS probe card manufacturing process. Background Technology
[0002] In semiconductor testing, MEMS probe cards are critical precision interface devices connecting the testing equipment and the chip, with the MEMS probe (MEMS-Pin) at their core. The fabrication of MEMS-Pins typically involves complex processes such as the deposition, patterning, etching, and electroplating of multiple thin films (e.g., oxide, nitride, and metal layers). Process fluctuations during manufacturing (e.g., uneven film thickness, abnormal contact resistance, defects) directly lead to performance degradation of the MEMS-Pin, reduced yield, and reliability risks in the final assembly and bonding.
[0003] Currently, the design of photomasks for MEMS-Pin manufacturing typically only includes patterns that form the probe's functional structure, lacking dedicated test patterns for online monitoring of process quality. Existing technologies limit the application of test patterns to simple tasks; however, the actual state of process parameters (such as uniformity within and between wafers, and the quality of inter-layer metal contact) cannot be quantitatively assessed in a timely and accurate manner. This lack of effective testing leads to many defective products being discovered only during final electrical testing or yield statistics, resulting in a large number of scraps and making it difficult to trace and pinpoint the root cause. Due to the lack of effective in-situ testing methods, process adjustments rely on experience, hindering data-driven precision optimization and severely limiting the improvement of MEMS probe card manufacturing yield and reliability. Summary of the Invention
[0004] To address the problem of ineffective testing in existing technologies, the present invention aims to provide a test pattern monitoring method for MEMS probe card manufacturing processes that enables effective testing.
[0005] To address the above problems, the present invention provides the following technical solution: A method for monitoring test patterns in MEMS probe card manufacturing processes, comprising: S1. Provide at least one mask, on which test patterns for MEMS probe fabrication are integrated; S2. Using the mask, perform a patterning manufacturing process for MEMS probes on the wafer, simultaneously forming the functional structure of the MEMS probes and the physical test structure corresponding to the test pattern distributed in the non-core area of the wafer; S3. After completing one or more preset key process layers, the physical test structure is measured to obtain parameter data reflecting the corresponding process quality; S4. Compare and analyze the parameter data with the preset process specification thresholds to obtain the process status evaluation results; S5. Based on the process status evaluation results, the manufacturing process parameters or procedures of the MEMS probe are adjusted accordingly.
[0006] In some embodiments, in step S1, the test pattern includes at least one of the following types: Test patterns of process parameters used to test the thickness of oxide films, metal thin films, or metal layers; Contact chain test patterns used to evaluate the quality of contact holes or through holes; Interconnect test patterns used to test the electrical properties of metal interconnect structures; Device performance test patterns used to test the properties of MEMS metals; Defect density test pattern used to test random defects in the process.
[0007] In some embodiments, the process parameter test pattern is a block test pattern; In step S3, the thickness of the metal thin film or the metal layer is measured by measuring the resistance of the process parameter test pattern, and the thickness of the oxide film is measured directly on the process parameter test pattern.
[0008] In some embodiments, the contact chain test pattern is a long chain structure formed by connecting multiple contact holes or through holes in series with metal wires. In step S3, the etching integrity, metal filling quality, and contact resistance of the contact hole are evaluated by measuring the resistance value of the contact chain test pattern.
[0009] In some embodiments, the interconnect test pattern is a structure of at least one intersecting or parallel metal interconnects; In step S3, the resistance, capacitance, and resistance change rate of the interconnect test pattern are detected to evaluate the electrical performance of the MEMS probe.
[0010] In some embodiments, the device performance test pattern is a spring structure pattern with metal thin film properties; In step S3, the electrical connection reliability and mechanical elasticity of the MEMS probe are evaluated by measuring the resistance or mechanical performance parameters of the device performance test pattern.
[0011] In some embodiments, the defect density test pattern is a serpentine structure, a comb-shaped structure, or a combination of both. In step S3, an electrical test is performed on the defect density test pattern to detect open circuit or short circuit defects, and the random defect density caused by the process is calculated based on the pattern area and the number of defects.
[0012] In some embodiments, in step S2, the test pattern is configured to form at least five test locations on the wafer, the test locations being located in the center, top, bottom, left, and right regions of the wafer, respectively.
[0013] In some embodiments, the non-core region on the wafer includes a dicing groove or the edge region of the wafer.
[0014] In some embodiments, in step S1, the design rules for the test pattern are exactly the same as the design rules for the MEMS probe functional structure.
[0015] The beneficial effects of this invention are: by integrating a variety of dedicated test patterns into the mask, key indicators such as film thickness, contact resistance, interconnect performance, basic device parameters and defect density can be quantitatively measured during the MEMS probe manufacturing process, thereby achieving quality control of each process layer in the manufacturing process, ensuring product yield, and ultimately improving the reliability of MEMS probes and their assembly bonding yield. Attached Figure Description
[0016] Figure 1 This is a flowchart of a test pattern monitoring method for a MEMS probe card manufacturing process according to the present invention; Figure 2 This is a schematic diagram of the structure of the test pattern of the process parameters in the test pattern monitoring method of the MEMS probe card manufacturing process of the present invention; Figure 3 This is a schematic diagram of the contact chain test pattern in the test pattern monitoring method for MEMS probe card manufacturing process according to the present invention. Figure 4 This is a schematic diagram of the interconnect test pattern structure of a test pattern monitoring method for MEMS probe card manufacturing process according to the present invention; Figure 5 This is a schematic diagram of the device performance test pattern of the test pattern monitoring method for MEMS probe card manufacturing process according to the present invention; Figure 6 This is a schematic diagram of the defect density test pattern of a test pattern monitoring method for MEMS probe card manufacturing process according to the present invention.
[0017] Figure label: 1. Process parameter test pattern; 2. Contact chain test pattern; 3. Interconnect test pattern; 4. Device performance test pattern; 5. Defect density test pattern. Detailed Implementation
[0018] 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 some embodiments of this application, and not all 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.
[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.
[0020] For ease of description of the first, second, and third directions in the embodiments of this application, the first direction is the left-right direction in the figures, the second direction is the front-back direction in the figures, and the third direction is the up-down direction in the figures. The x-axis arrow direction is referred to as the "right" direction, the y-axis arrow direction as the "up" direction, and the z-axis arrow direction as the "back" direction, but these are not the sole limitations in the actual application of this application.
[0021] like Figure 1 As shown, this embodiment provides a test pattern monitoring method for MEMS probe card manufacturing process, which includes: S1. Provide at least one mask, on which test patterns for MEMS probe fabrication are integrated; S2. Using a mask, perform a patterned manufacturing process for MEMS probes on a wafer, simultaneously forming the functional structure of the MEMS probes and the physical test structure corresponding to the test patterns distributed in the non-core area of the wafer. S3. After completing one or more preset key process layers, measure the physical test structure to obtain parameter data reflecting the corresponding process quality; S4. Compare and analyze the parameter data with the preset process specification thresholds to obtain the process status evaluation results; S5. Based on the process status assessment results, adjust the manufacturing process parameters or procedures of the MEMS probes according to feedback.
[0022] like Figure 1As shown, this embodiment provides a photolithographic mask with test patterns for manufacturing MEMS probe cards, which includes at least one mask; the pattern area of the mask includes a functional pattern area and a test pattern area; the functional pattern area is used to form functional patterns on the wafer; at least one set of test patterns is disposed in the test pattern area; the design rules of the test patterns are matched with the design rules of the functional pattern area.
[0023] Specifically, a mask is designed and provided, and according to the MEMS-Pin process flow (e.g., including bottom oxide deposition, first metal layer patterning, dielectric layer deposition and via etching, second metal layer (spring layer) electroplating and patterning, etc.), when designing the mask for patterning each layer, dedicated test patterns are designed and integrated simultaneously, and these patterns are concentrated in the area corresponding to the wafer dicing slot.
[0024] Specifically, after completing the key process of electroplating and patterning the second metal layer, the wafer is subjected to process testing of the test pattern, measuring the resistance of the standard square pattern at five locations, calculating the thickness and uniformity of the second metal layer; measuring the contact chain resistance at five locations; measuring the resistance value of the spring structure pattern; and conducting continuity and insulation tests on the serpentine and comb-shaped structures.
[0025] Specifically, actions are taken based on the assessment report to intervene and control the original process results and provide feedback adjustments.
[0026] Scenario 1: If the thickness of the second metal layer in the edge area of the wafer is found to be generally lower than that in the center area, it is determined that the electroplating solution is unevenly distributed. The information is fed back to the electroplating equipment, and the layout is adjusted in the next batch of production to improve uniformity.
[0027] Scenario 2: If the contact chain resistance of all wafers in a certain batch is too high, it is determined that the cleaning after the through-hole etching is incomplete or the alloying process is insufficient. Feedback information is sent to the cleaning or heat treatment process to optimize the cleaning formula or increase the alloying temperature or time.
[0028] Scenario 3: If a comb-shaped structure is frequently tested only at a specific location, it may correspond to a local problem in the lithography machine or coating machine, triggering preventative maintenance for that specific equipment.
[0029] Through the closed-loop process described above, we can not only monitor the process quality of each batch of products in real time, but also continuously accumulate data to drive the manufacturing process to iteratively optimize towards a more stable, uniform, and efficient direction, ultimately achieving a step-by-step improvement in the yield and reliability of MEMS probe card products.
[0030] Optionally, a new step S2.5 is added between steps S2 and S3. This step involves introducing electronic monitoring equipment to scan and analyze the physical test structure, obtain its shape parameters, and then re-determine them. This ensures that the shape and size of the physical test structure are consistent with the shape and size of the test pattern.
[0031] Optionally, step S4 further includes: inputting current and historical parameter data and corresponding final product yield data into a pre-trained machine learning model; using the model output to predict the yield of the current batch of products, or to provide root cause diagnosis and adjustment suggestions for process anomalies. The massive multi-dimensional test data (film thickness, resistance, capacitance, defect maps, etc.) generated by this method is correlated with the final MEMS probe yield and performance database, and intelligent analysis is achieved using machine learning algorithms.
[0032] Optionally, in this embodiment, the photomask further includes: a photomask frame disposed outside the photomask; the photomask includes a photomask strip, and a connecting layer is disposed on the photomask strip; a protective layer is disposed on the connecting layer, which can adhere the protective layer to the photomask strip, preventing the protective layer from detaching. The protective layer can prevent the photomask from being damaged by impact during long-term use, thus improving the reliability of the photomask.
[0033] Optionally, in this embodiment, the mask also includes: an isolation component disposed on the mask, which is used to isolate two stacked masks. The isolation component includes cylindrical metal positioning posts disposed at the four corners of the bottom surface of the mask, and positioning holes disposed on the top surface of the mask and adapted to the positioning posts; grip handles for holding are provided on the left and right side walls of the mask. When the mask is idle, due to the isolation component and grip handles, when handling the mask, the personnel can directly hold the grip handles to align and place the mask on another mask and limit its position, which is beneficial for storage and improves the reliability of protecting the mask.
[0034] like Figure 2-6 As shown, in this embodiment, in step S1, the test pattern includes at least one of the following types: Test pattern 1 for process parameters used to test the thickness of oxide films, metal thin films or metal layers; Contact chain test pattern 2 used to evaluate the quality of contact holes or through holes; Interconnect test pattern 3, used to test the electrical performance of metal interconnect structures; Device performance test graph 4 used to test the properties of MEMS metals; Defect density test graph 5, used to test random defects in the process.
[0035] In this embodiment, the process parameter test pattern 1 is a block test pattern; In step S3, the thickness of the metal thin film or metal layer is measured by resistance testing of process parameter test pattern 1, and the thickness of the oxide film is measured directly on process parameter test pattern 1.
[0036] like Figure 2 As shown in Figure 1, the process parameter test pattern is as follows: A standard square pattern is designed for subsequent measurement of the resistance of the square pattern of the second metal layer (such as a nickel alloy). The thickness is then accurately calculated using the resistance test data. Simultaneously, a corresponding square pattern is also designed in the oxide layer region for ellipsometer measurement of the film thickness.
[0037] In this embodiment, the contact chain test pattern 2 is a long chain structure formed by connecting multiple contact holes or through holes in series with metal wires; In step S3, the etching integrity, metal filling quality, and contact resistance of the contact hole are evaluated by measuring the resistance value of the contact chain test pattern 2.
[0038] like Figure 3 As shown in Figure 2, the contact chain test pattern involves designing a long chain composed of thousands (preferably 5000) of contact holes or vias connected in series via metal wires. The resistance of the entire chain is measured using a metal bridge Rs test. Since the vias connect to the underlying metal layer, the resistance, connectivity, and process quality of each contact hole or via in the wafer can be evaluated. If the holes are not completely etched or poorly filled, the chain resistance will be abnormally high, allowing for the detection of anomalies, data acquisition, and data analysis.
[0039] like Figure 4 As shown, in this embodiment, the interconnect test pattern 3 is a structure of at least one interconnected or parallel metal interconnect.
[0040] like Figure 4 As shown, in this embodiment, the interconnect test pattern is at least one of the following: swastika shape, back shape, interdigitated shape, or parallel plate structure.
[0041] In step S3, the resistance, capacitance, and resistance change rate of the interconnect test pattern 3 are tested to evaluate the electrical performance of the MEMS probe.
[0042] like Figure 4 As shown in Figure 3, the interconnect test pattern includes: designing a set of "swastika" or "return" shaped metal interconnect structures to measure the sheet resistance and line resistance of the metal layer; designing a set of "interdigitated" or "parallel plate" metal interconnect structures to measure the intralayer capacitance and interlayer capacitance; and designing a long and narrow metal interconnect structure with a large current to evaluate the electromigration reliability of the metal interconnect structure and to evaluate the quality and thickness uniformity of the dielectric layer.
[0043] This embodiment also provides a testing method, contact resistance testing: In the MEMS process, the connection and stacking process between thin films (oxide film, nitride film, etc.) and metal films (Au, Cu, Ni, Ti, etc.) is mainly formed. The relevant process parameters are tested by special patterns (process parameter requirements, designing relevant non-layer metal film stacking patterns).
[0044] like Figure 5 As shown, in this embodiment, device performance test pattern 4 is a spring structure pattern with metal thin film properties; The electrical connection reliability and mechanical resilience of the MEMS probe are evaluated by measuring the resistance or mechanical performance parameters of the device performance test pattern 4.
[0045] Device performance test pattern 4: Design several spring structure patterns with metal thin film properties of different widths. By measuring the resistance value and swing amplitude of the spring structure pattern, evaluate the electrical connection reliability and mechanical elasticity of the MEMS probe to see if it meets the core indicators. Apply this to the subsequent process of MEMS probe, such as electroplating.
[0046] like Figure 6 As shown, in this embodiment, the defect density test pattern 5 is a serpentine structure, a comb-shaped structure, or a combination of both. Electrical tests are performed on defect density test pattern 5 to detect open or short circuit defects, and the random defect density caused by the process is calculated based on the pattern area and the number of defects.
[0047] Defect density test pattern 5: Serpentine structure: a very long and tortuous metal line; Comb structure: two sets of intersecting "comb"-shaped metal lines; Combined structure: a combination of serpentine and comb structures; Defects (such as oxide film, nitride film, metal film damage, surface roughness, electrical shock damage, etc.) can be detected by defect testing instruments (with optical or electronic scanning graphic comparison function).
[0048] Principle: By measuring the open or short circuits between these structures (through the misalignment between the upper and lower membrane structures and the corresponding superposition specifications, if the specifications are exceeded, it is considered a defect), and by identifying and summarizing the defects graphically, the density of the unit defect particles that cause the failure can be calculated.
[0049] In this embodiment, in step S2, the test pattern is configured to form at least five test positions on the wafer, and the test positions are respectively located in the center, top, bottom, left and right regions of the wafer.
[0050] Through the above steps, the test patterns and functional patterns will be formed simultaneously on the wafer. When photolithography, etching or electroplating is performed using a mask, the functional patterns of the MEMS probe and various test patterns located in the dicing groove are manufactured simultaneously. These test patterns are copied to five positions on the wafer: center, top, bottom, left and right. By laying out test patterns at multiple points, the process uniformity within and between wafers can be effectively monitored and evaluated, providing direct data support for the optimization and stability control of the process window.
[0051] In this embodiment, when the mask is used for wafer exposure, the test pattern is set in the non-core functional area of the wafer.
[0052] In this embodiment, the non-core area on the wafer includes dicing grooves or the edge area of the wafer.
[0053] In this embodiment, in step S1, the design rules for the test pattern are exactly the same as the design rules for the functional structure of the MEMS probe.
[0054] In summary, this invention provides a test pattern monitoring method for MEMS probe card manufacturing process. By integrating multiple dedicated test patterns into the mask, key indicators such as film thickness, contact resistance, interconnect performance, basic device parameters, and defect density can be quantitatively measured during MEMS probe manufacturing. This yields parameter data that reflects process quality. By comparing and analyzing the data, a process status evaluation structure can be obtained, thereby enabling feedback adjustment of the process progress. This achieves quality control of each process layer in the manufacturing process, ensures product yield, and ultimately improves the reliability of MEMS probes and their assembly bonding yield.
[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.
Claims
1. A method for monitoring test patterns in the manufacturing process of a MEMS probe card, characterized in that, include: S1. Provide at least one mask, on which test patterns for MEMS probe fabrication are integrated; S2. Using the mask, perform a patterning manufacturing process for MEMS probes on the wafer, simultaneously forming the functional structure of the MEMS probes and the physical test structure corresponding to the test pattern distributed in the non-core area of the wafer; S3. After completing one or more preset key process layers, the physical test structure is measured to obtain parameter data reflecting the corresponding process quality; S4. Compare and analyze the parameter data with the preset process specification thresholds to obtain the process status evaluation results; S5. Based on the process status evaluation results, the manufacturing process parameters or procedures of the MEMS probe are adjusted accordingly.
2. The test pattern monitoring method for MEMS probe card manufacturing process according to claim 1, characterized in that: In step S1, the test pattern includes at least one of the following types: Test patterns of process parameters used to test the thickness of oxide films, metal thin films, or metal layers; Contact chain test patterns used to evaluate the quality of contact holes or through holes; Interconnect test patterns used to test the electrical properties of metal interconnect structures; Device performance test patterns used to test the properties of MEMS metals; Defect density test pattern used to test random defects in the process.
3. The test pattern monitoring method for MEMS probe card manufacturing process according to claim 2, characterized in that: The process parameter test pattern is a block test pattern; In step S3, the thickness of the metal thin film or the metal layer is measured by measuring the resistance of the process parameter test pattern, and the thickness of the oxide film is measured directly on the process parameter test pattern.
4. The test pattern monitoring method for MEMS probe card manufacturing process according to claim 2, characterized in that: The contact chain test pattern is a long chain structure formed by multiple contact holes or through holes connected in series by metal wires. In step S3, the etching integrity, metal filling quality, and contact resistance of the contact hole are evaluated by measuring the resistance value of the contact chain test pattern.
5. The test pattern monitoring method for MEMS probe card manufacturing process according to claim 2, characterized in that: The interconnect test pattern is a structure of at least one intersecting or parallel metal interconnect. In step S3, the resistance, capacitance, and resistance change rate of the interconnect test pattern are detected to evaluate the electrical performance of the MEMS probe.
6. The test pattern monitoring method for MEMS probe card manufacturing process according to claim 2, characterized in that: The device performance test pattern is a spring structure pattern with metal thin film properties; In step S3, the electrical connection reliability and mechanical elasticity of the MEMS probe are evaluated by measuring the resistance or mechanical performance parameters of the device performance test pattern.
7. The test pattern monitoring method for MEMS probe card manufacturing process according to claim 2, characterized in that: The defect density test pattern is a serpentine structure, a comb-shaped structure, or a combination of both. In step S3, an electrical test is performed on the defect density test pattern to detect open circuit or short circuit defects, and the random defect density caused by the process is calculated based on the pattern area and the number of defects.
8. The test pattern monitoring method for MEMS probe card manufacturing process according to claim 1, characterized in that: In step S2, the test pattern is configured to form at least five test positions on the wafer, the test positions being located in the center, top, bottom, left, and right regions of the wafer, respectively.
9. The test pattern monitoring method for MEMS probe card manufacturing process according to claim 1, characterized in that: The non-core region on the wafer includes dicing grooves or the edge region of the wafer.
10. The test pattern monitoring method for MEMS probe card manufacturing process according to claim 8 or 9, characterized in that: In step S1, the design rules for the test pattern are exactly the same as the design rules for the MEMS probe functional structure.