A method for optimizing the surface morphology of MEMS probes

Abstract

This invention relates to a method for optimizing the surface morphology of a MEMS probe, comprising the following steps: Step 1: Constructing a structural drawing of the MEMS probe and determining its external dimensions; Step 2: Obtaining a pre-formed MEMS probe; Step 3: Using a picosecond laser to perform in-situ surface morphology optimization on the MEMS probe obtained in Step 2. Based on the size of the slag on the surface of the MEMS probe and the actual thickness of the MEMS probe, an adaptive local fixed-point slag removal mode or a global uniform removal mode is selected. The surface of the MEMS probe is uniformly removed using a parallel scanning method to obtain a MEMS probe with a smooth surface. This invention matches differentiated laser processing parameters to different processing conditions, accurately removing slag and spherical recast layers generated by cold ablation, eliminating the need for subsequent processing such as mechanical polishing and chemical etching. This effectively avoids stress deformation and chemical impurity contamination, improves the surface smoothness and electrical contact performance of the MEMS probe, exhibits good process stability, and is suitable for large-scale precision manufacturing of MEMS probes.

Description

Technical Field

[0001] This invention relates to the field of MEMS probe manufacturing technology, and in particular to a method for optimizing the surface morphology of a MEMS probe. Background Technology

[0002] MEMS probes are widely used in wafer testing, chip electrical testing, and other scenarios. Their tip morphology and surface flatness directly determine contact reliability and elastic deformation performance. Traditional MEMS probe manufacturing often employs ion etching and deep silicon etching processes, which have significant limitations in processing hard and brittle materials and high aspect ratio probe structures.

[0003] Ultrafast lasers, with their advantages of non-contact processing, small heat-affected zone, and no thermal deformation from cold ablation, have gradually replaced traditional etching as the mainstream solution for MEMS probe forming and processing. However, after laser cold ablation, the molten material is prone to forming a spherical recast layer at the probe edge under the action of surface tension, and residual slag remains on the surface, which seriously affects the dimensional accuracy and contact performance of the probe.

[0004] Existing methods for optimizing probe surface morphology mainly involve mechanical polishing or chemical etching. Mechanical polishing has poor removal accuracy and insufficient process stability, and it is easy to introduce structural stress that leads to probe tip deformation. Chemical etching is prone to corroding non-target areas of the probe and introducing impurities, which can interfere with subsequent coating, packaging and other processes. Summary of the Invention

[0005] This invention provides a method for optimizing the surface morphology of a MEMS probe to solve the above-mentioned technical problems.

[0006] To address the aforementioned technical problems, this invention provides a method for optimizing the surface morphology of a MEMS probe, comprising the following steps:

[0007] Step 1: Construct a structural drawing of the MEMS probe and determine its external dimensions;

[0008] Step 2: Obtain a preliminary MEMS probe;

[0009] Step 3: The MEMS probe obtained in Step 2 is subjected to in-situ surface morphology optimization using a picosecond laser. Based on the size of the slag on the surface of the MEMS probe and the actual thickness of the MEMS probe, the local fixed-point slag removal mode or the overall uniform slag removal mode is adaptively selected. The surface of the MEMS probe is uniformly slag removed in a parallel scanning manner to obtain a MEMS probe with a smooth surface.

[0010] Preferably, step 2 uses picosecond laser processing to obtain a pre-formed MEMS probe.

[0011] Preferably, step 3 further includes adjusting the processing parameters of the picosecond laser, which include at least energy density, repetition frequency, spot diameter, scanning speed, and number of scans.

[0012] Preferably, the processing parameters of the picosecond laser are: laser power 0.1W to 1.5W, repetition frequency 200kHz to 1000kHz, spot diameter 5 to 30μm, number of scans 2 to 10, and scanning speed 50 to 3000mm / s.

[0013] Preferably, the localized fixed-point slag removal mode is suitable for working conditions where the slag size is 0.5 to 4 μm.

[0014] Preferably, the processing parameters in the local fixed-point slag removal mode are: scanning speed 1000-3000 mm / s, laser power 0.4-0.8 W, and scanning spacing 0.2-2 μm.

[0015] Preferably, the overall uniform depletion mode is suitable for situations where the thickness of the MEMS probe is greater than a preset thickness.

[0016] Preferably, the processing parameters in the overall uniform removal mode are: scanning speed 50-3000 mm / s, laser power 0.1-0.8 W, and scanning spacing 1-4 μm.

[0017] Preferably, the wavelength of the picosecond laser is 355nm.

[0018] Preferably, the thickness of a single uniform removal is 1–10 μm.

[0019] Compared with existing technologies, the MEMS probe surface morphology optimization method provided by this invention has the following advantages:

[0020] 1. This invention matches different laser processing parameters for different processing conditions, which can accurately remove the slag and spherical recast layer generated by laser cold ablation. It does not require subsequent treatments such as mechanical polishing and chemical etching. It can avoid tip deformation caused by mechanical stress and impurity contamination caused by chemical agents, and improve the surface flatness and electrical contact performance of MEMS probes. It has excellent process stability and is suitable for large-scale precision manufacturing.

[0021] 2. This invention can complete surface defect repair using only laser, simplifying the process flow and reducing process complexity and production costs; moreover, laser non-contact processing combined with specific process parameters results in good processing consistency and high batch repeatability of products.

[0022] 3. The morphology optimization process can be carried out in situ with the probe laser forming process, and is compatible with existing laser processing production lines without the need for additional equipment and auxiliary materials. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the laser optimization route in Embodiment 1 of the present invention;

[0024] Figure 2 This is a schematic diagram of the laser optimization route in Embodiment 2 of the present invention.

[0025] Figure 1 In the middle: 11-MEMS probe, 12-slag / recasting layer, 13-scanning optical path;

[0026] Figure 2 In the middle: 21-MEMS probe, 22-slag / recasting layer, 23-scanning optical path. Detailed Implementation

[0027] To illustrate the technical solutions of the invention in more detail, specific embodiments are listed below to demonstrate the technical effects; it should be emphasized that these embodiments are used to illustrate the invention and not to limit the scope of the invention.

[0028] The MEMS probe surface morphology optimization method provided by this invention includes the following steps:

[0029] Step 1: Construct a structural drawing (such as a 3D drawing) of the MEMS probe and determine the external dimensions of the MEMS probe;

[0030] Step 2: Obtain a preliminary MEMS probe;

[0031] Step 3: The MEMS probe obtained in Step 2 is subjected to in-situ surface morphology optimization using a picosecond laser. Based on the size of the slag on the surface of the MEMS probe and the actual thickness of the MEMS probe, the local fixed-point slag removal mode or the overall uniform slag removal mode is adaptively selected. The surface of the MEMS probe is uniformly slag removed in a parallel scanning manner to obtain a MEMS probe with a smooth surface.

[0032] This invention employs a dual-mode, on-demand switching method to precisely remove slag and recast layers without the need for polishing or chemical corrosion. This avoids mechanical stress deformation and chemical impurity contamination, and improves the surface smoothness and contact conductivity of the probe.

[0033] In some embodiments, step 2 uses picosecond laser processing to obtain a pre-formed MEMS probe. In this way, the forming and subsequent morphology trimming share the same set of laser equipment, which is compatible with existing laser production lines and does not require additional equipment and auxiliary materials, thus reducing equipment investment costs.

[0034] In some embodiments, step 3 further includes adjusting the processing parameters of the picosecond laser. The processing parameters include at least energy density, repetition frequency, spot diameter, scanning speed, and number of scans. By adjusting the multi-dimensional parameters, different defect conditions can be adapted to improve the process adjustability and processing applicability.

[0035] In some embodiments, the processing parameters of the picosecond laser are: laser power 0.1W to 1.5W, repetition frequency 200kHz to 1000kHz, spot diameter 5 to 30μm, number of scans 2 to 10, and scanning speed 50 to 3000mm / s, resulting in high product processing stability and good repeatability.

[0036] In some embodiments, the wavelength of the picosecond laser is 355nm, resulting in a small heat-affected zone, which avoids thermal deformation of the probe substrate and further ensures processing accuracy.

[0037] In some embodiments, the thickness of a single uniform removal is 1 to 10 μm, and the removal thickness is controllable to prevent over-cutting damage to the probe substrate size and ensure the finished product size qualification rate.

[0038] Example 1

[0039] In some embodiments, the localized fixed-point slag removal mode is suitable for working conditions where the molten slag size is 0.5–4 μm. In this embodiment, please refer to the relevant documentation. Figure 1 The slag size is 3μm, so there is no need to remove the substrate of MEMS probe 11 over a large area. Only a small area (special location) of slag / recast layer 12 needs to be processed.

[0040] In this embodiment, the processing parameters in the local fixed-point slag removal mode are: scanning speed 1000~3000mm / s, laser power 0.4~0.8W, scanning spacing 0.2~2μm, scanning along the longitudinal scanning optical path 13. This set of narrow-domain parameters accurately aligns with the local waste slag, and the fixed-point removal is done without unnecessary cutting, preserving the original structural accuracy of the MEMS probe 11 to the greatest extent.

[0041] Example 2

[0042] In some embodiments, the overall uniform removal mode is suitable for situations where the MEMS probe thickness is greater than a preset thickness, such as... Figure 2 As shown, for the case where the thickness of the MEMS probe 21 is too large, a transverse scanning optical path 23 with full distribution can be used to scan the entire surface of the MEMS probe 21 uniformly to obtain a suitable probe thickness. At the same time, the slag / recast layer 22 on the surface is removed, and the overall thickness specification of the probe is unified, resulting in strong product size uniformity.

[0043] In this embodiment, the processing parameters in the overall uniform removal mode are: scanning speed 50-3000 mm / s, laser power 0.1-0.8 W, scanning spacing 1-4 μm. The full-domain scanning parameters achieve uniform surface removal, resulting in uniform surface roughness of the MEMS probe 21 and optimizing subsequent electrical contact performance.

[0044] In summary, this invention utilizes two optimization modes—flexible switching between slag size and probe thickness—along with graded laser processing parameters, to achieve in-situ morphology trimming using picosecond lasers. This eliminates the need for mechanical polishing and chemical etching processes, avoiding stress deformation and impurity contamination issues. Furthermore, it allows for continuous production with the preceding probe laser forming process, simplifying the manufacturing process, reducing production costs, and providing excellent processing consistency, which is beneficial for the mass production of precision MEMS probes.

[0045] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for optimizing the surface morphology of a MEMS probe, characterized in that, Includes the following steps: Step 1: Construct a structural drawing of the MEMS probe and determine its external dimensions; Step 2: Obtain a preliminary MEMS probe; Step 3: The MEMS probe obtained in Step 2 is subjected to in-situ surface morphology optimization using a picosecond laser. Based on the size of the slag on the surface of the MEMS probe and the actual thickness of the MEMS probe, the local fixed-point slag removal mode or the overall uniform slag removal mode is adaptively selected. The surface of the MEMS probe is uniformly slag removed in a parallel scanning manner to obtain a MEMS probe with a smooth surface.

2. The MEMS probe surface morphology optimization method as described in claim 1, characterized in that, Step 2 uses picosecond laser processing to obtain a preliminary MEMS probe.

3. The MEMS probe surface morphology optimization method as described in claim 2, characterized in that, Step 3 also includes adjusting the processing parameters of the picosecond laser, which include at least energy density, repetition frequency, spot diameter, scanning speed, and number of scans.

4. The MEMS probe surface morphology optimization method as described in claim 3, characterized in that, The processing parameters of the picosecond laser are: laser power 0.1W to 1.5W, repetition frequency 200kHz to 1000kHz, spot diameter 5 to 30μm, number of scans 2 to 10, and scanning speed 50 to 3000mm / s.

5. The MEMS probe surface morphology optimization method as described in claim 4, characterized in that, The localized fixed-point slag removal mode is suitable for working conditions where the slag size is 0.5 to 4 μm.

6. The MEMS probe surface morphology optimization method as described in claim 5, characterized in that, The processing parameters under the local fixed-point slag removal mode are: scanning speed 1000~3000mm / s, laser power 0.4~0.8W, and scanning spacing 0.2~2μm.

7. The MEMS probe surface morphology optimization method as described in claim 4, characterized in that, The overall uniform de-masking mode is suitable for situations where the thickness of the MEMS probe is greater than the preset thickness.

8. The MEMS probe surface morphology optimization method as described in claim 7, characterized in that, The processing parameters under the overall uniform removal mode are: scanning speed 50-3000 mm / s, laser power 0.1-0.8 W, and scanning spacing 1-4 μm.

9. The MEMS probe surface morphology optimization method as described in claim 1, characterized in that, The wavelength of the picosecond laser is 355nm.

10. The MEMS probe surface morphology optimization method as described in claim 1, characterized in that, The thickness of a single uniform removal is 1–10 μm.

Images