Composite substrate for femtosecond laser processing probe and preparation method thereof
By using a composite substrate design, hollow cavities and phase change materials are employed to alleviate thermal stress, thus solving the problems of thermal stress concentration and debris adhesion in femtosecond laser processing probes. This improves processing accuracy and yield, and simplifies the fabrication process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- MAXONE SEMICON CO LTD
- Filing Date
- 2026-03-27
- Publication Date
- 2026-05-19
AI Technical Summary
The substrate of existing femtosecond laser processing probes is prone to thermal stress concentration and debris adhesion during processing, which leads to damage to structural integrity and reduced accuracy. Existing optimization solutions have limited effectiveness and increase equipment complexity.
The composite substrate design includes a base layer, a hollow cavity, and a functional filling layer. The hollow cavity serves as a channel for airflow debris removal and plasma suction, while the functional filling layer is a phase change material. The combination of a three-dimensional mesh structure and the thermal expansion regulation of the phase change material alleviates thermal stress and removes debris.
It effectively reduces the risk of microcracks and interface delamination, improves debris removal efficiency, increases processing accuracy and yield, simplifies the preparation process, and is compatible with femtosecond laser processing systems.
Smart Images
Figure CN122058058A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of femtosecond laser processing probe technology, and in particular to a composite substrate for femtosecond laser processing probes and its preparation method. Background Technology
[0002] In the field of high-precision probe manufacturing, femtosecond lasers, with their unique advantages of ultra-short pulse width, extremely high peak power, and minimal heat-affected zone, have become the core method for processing high-hardness, brittle, and heat-sensitive probe materials such as diamond, silicon carbide, and titanium nitride. The substrate, as a key load-bearing component in femtosecond laser probe processing, directly affects the absorption of laser energy, the release of thermal stress during processing, the efficiency of removing debris generated by laser ablation, and the quality of probe release and transfer after processing. It is a crucial factor determining probe processing accuracy and yield.
[0003] In existing technologies, the substrates used for femtosecond laser processing probes are mostly rigid, solid structures made of a single material. Although femtosecond laser processing is defined as "cold processing," the extremely high energy density in certain areas during the process still creates an instantaneous thermal gradient at the interface between the probe material and the substrate. Because the thermal expansion coefficients of the rigid substrate and the probe material are difficult to match, thermal stress concentration easily occurs at the interface, leading to interface delamination, microcracks, and even cracking of the probe itself, severely compromising the probe's structural integrity. Simultaneously, nanoscale particles and molten material generated by laser ablation easily adhere to the substrate surface or microstructure gaps, making complete removal difficult. This not only causes secondary contamination of the probe but also easily forms a recast layer on the probe surface, significantly reducing the probe's processing accuracy and performance.
[0004] Currently, most of the improvement solutions for the above problems are single-dimensional optimizations, such as alleviating thermal stress by improving the thermal conductivity of the substrate, or collecting debris by adding an external chip collection device to the processing equipment. The improvement effect of such optimization solutions is limited, and the external chip collection device will increase the structural complexity of the processing equipment and increase the processing cost, which cannot meet the needs of large-scale and batch processing of high-precision probes. Summary of the Invention
[0005] This invention provides a composite substrate for femtosecond laser processing probes and a method for preparing the same, in order to solve the aforementioned technical problems.
[0006] To address the aforementioned technical problems, this invention provides a composite substrate for a femtosecond laser processing probe, comprising a base layer, a hollow cavity, and an optional functional filling layer; the hollow cavity is a three-dimensional mesh-like hollow structure disposed within the base layer, which constitutes an airflow chip removal and plasma suction channel; the functional filling layer is made of a phase change material, and the functional filling layer is selectively filled within the hollow cavity.
[0007] Preferably, the phase change material is a low-melting-point alloy or an organic phase change material.
[0008] Preferably, the low-melting-point alloy is a bismuth-tin alloy, and the organic phase change material is polyethylene glycol.
[0009] Preferably, the substrate is made of one of silicon wafers, ceramics, or metal composite materials.
[0010] Preferably, the metal composite plate is an aluminum-copper composite substrate, wherein the base layer of the aluminum-copper composite substrate is aluminum and the upper surface is composite with a copper plate.
[0011] The present invention also provides a method for preparing a composite substrate for a femtosecond laser processing probe as described above, comprising the following steps:
[0012] Step 1: Select a substrate material and use photolithography, deep reactive ion etching, or laser engraving to prepare a mold with a groove structure on the substrate.
[0013] Step 2: Deposit a sacrificial layer on the inner wall of the groove structure, fill the outer side of the sacrificial layer with silicon nitride or silicon dioxide using chemical vapor deposition to form an intermediate layer, and remove the sacrificial layer by wet etching to obtain a three-dimensional mesh hollow structure with horizontal connectivity, forming the hollow cavity;
[0014] Step 3: Based on the characteristics of the probe material processed by femtosecond laser, selectively fill the hollow cavity with phase change material to form the functional filling layer;
[0015] Step 4: Polish the prepared substrate to obtain the composite substrate.
[0016] Preferably, in step 1, when the substrate is a silicon wafer, the mold with the groove structure is prepared by photolithography combined with deep reactive ion etching.
[0017] Preferably, in step 1, when the substrate is ceramic, the mold with the groove structure is prepared by 3D printing or laser engraving.
[0018] Preferably, in step 1, when the base layer is a metal composite plate, the mold with the groove structure is prepared by laser engraving process.
[0019] Preferably, in step 2, the sacrificial layer is one of silicon dioxide, polyethylene oxide, aryltriazine polymer, or gel precursor.
[0020] Compared with the prior art, the composite substrate for femtosecond laser processing probes and its preparation method provided by the present invention have the following advantages:
[0021] 1. This invention utilizes the hollow cavity to form its own airflow chip removal and plasma suction channels, which can quickly remove the chips and plasma generated during processing, improving the chip removal efficiency by 90% and avoiding secondary pollution and recast layer formation from the source.
[0022] 2. The hollow cavity in this invention adopts a three-dimensional mesh-connected structure, and its sidewalls have the ability to undergo small elastic deformation, which can effectively absorb the thermal expansion stress between the probe material and the substrate. Combined with the adjustment effect of the phase change material on the coefficient of thermal expansion, the probability of microcracks and interface delamination is greatly reduced.
[0023] 3. The preparation method provided by the present invention simplifies the preparation steps by combining the sacrificial layer with the substrate layer. The hollow cavity can avoid serious damage to the back of the material caused by laser reflection after penetration. The preparation process is compatible with the femtosecond laser processing system and does not require additional equipment. Attached Figure Description
[0024] Figure 1 This is a three-dimensional structural diagram of a composite substrate for a femtosecond laser processing probe according to a specific embodiment of the present invention;
[0025] Figure 2 and Figure 3 These are schematic diagrams illustrating two application methods of a femtosecond laser processing probe according to a specific embodiment of the present invention.
[0026] In the diagram: 01-probe, 10-substrate, 20-hollow cavity. 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 present invention provides a composite substrate for femtosecond laser processing probes and a method for preparing the same, such as... Figure 1 As shown, the system includes a substrate 10, a hollow cavity 20, and an optional functional filling layer (not shown). The hollow cavity 20 is a three-dimensional mesh-like hollow structure located inside the substrate 10. It forms an airflow chip removal and plasma suction channel, which can quickly remove nanoscale debris and plasma generated by laser processing, thus avoiding secondary pollution and recast layer formation at the source. At the same time, the sidewalls of the three-dimensional mesh-like hollow structure have micro-elastic deformation capabilities, which can effectively absorb thermal expansion stress. The functional filling layer is made of a phase change material and is selectively filled in the hollow cavity 20. It can adjust the thermal expansion coefficient between the substrate and the probe according to the probe material characteristics, further alleviating thermal stress concentration and reducing the risk of microcracks and interface delamination.
[0029] In some embodiments, the phase change material is a low-melting-point alloy or an organic phase change material, which can undergo a solid-liquid phase change within the processing temperature range, effectively buffering thermal shock and adapting to the thermal expansion characteristics of different probe materials.
[0030] In some embodiments, the low-melting-point alloy is a bismuth-tin alloy, and the organic phase change material is polyethylene glycol. Both have stable phase change temperatures and good thermal conductivity, which can accurately match the processing requirements of high heat-sensitive probe materials such as diamond and silicon carbide.
[0031] In some embodiments, the substrate 10 is made of one of silicon wafers, ceramics, or metal composite materials, which can be flexibly selected according to the processing scenario, taking into account both structural strength and processing compatibility.
[0032] In some embodiments, the metal composite plate is an aluminum-copper composite substrate, wherein the base layer of the aluminum-copper composite substrate is aluminum and the upper surface is composite with a copper plate, which not only ensures the overall rigidity of the substrate, but also improves the local heat conduction efficiency and accelerates the diffusion of processing heat.
[0033] The present invention also provides a method for preparing a composite substrate for a femtosecond laser processing probe as described above, comprising the following steps:
[0034] Step 1: Select the substrate 10 material and use photolithography, deep reactive ion etching or laser engraving to prepare a mold with a groove structure on the substrate 10. This step can precisely control the groove size, laying the foundation for the subsequent molding of the hollow cavity 20. Different materials are adapted to specific processes to ensure molding accuracy.
[0035] Step 2: A sacrificial layer is deposited on the inner wall of the groove structure. A chemical vapor deposition (CVD) process is used to fill silicon nitride or silicon dioxide on the outside of the sacrificial layer to form an intermediate layer. The sacrificial layer is removed by wet etching to obtain a three-dimensional mesh hollow structure with horizontal connections, forming the hollow cavity 20. This process can achieve high-precision hollow structure forming, avoid laser penetration causing damage to the back of the material, and the material of the intermediate layer can improve the structural stability and service life of the hollow cavity 20.
[0036] Step 3: Based on the material properties of the probe 01 processed by femtosecond laser, a phase change material is selectively filled into the hollow cavity 20 to form the functional filling layer. The filling ratio can be flexibly adjusted to achieve precise matching of the thermal expansion coefficient and maximize the release of thermal stress.
[0037] Step 4: Polish the prepared substrate to obtain the composite substrate. This improves the surface flatness of the substrate, ensures the positioning accuracy and fit during probe processing, and further improves the probe processing yield. Specifically, when processing probe 01 using this composite substrate structure, the following can be used: Figure 2The method involves the probe traversing multiple hollow cavities 20; alternatively, it can be used... Figure 3 In this manner, the probe 01 is located between two hollow cavities 20, which can achieve the functions of thermal stress release and debris discharge.
[0038] In some embodiments, in step 1, when the substrate 10 is a silicon wafer, the mold with the groove structure can be prepared by photolithography combined with deep reactive ion etching (DRIE) process, which can achieve groove forming with submicron precision and meet the needs of high-precision probe processing.
[0039] In some embodiments, in step 1, when the base layer 10 is ceramic, the mold with the groove structure can be prepared by 3D printing or laser engraving, which can flexibly customize complex groove shapes to adapt to the processing scenarios of irregular probes.
[0040] In some embodiments, in step 1, when the base layer 10 is a metal composite plate, the mold with the groove structure is prepared by laser engraving process, which can efficiently realize the hollow forming of metal material, taking into account both production efficiency and structural accuracy.
[0041] In some embodiments, in step 2, the sacrificial layer is one of silicon oxide, polyethylene oxide, aryltriazine polymer or gel precursor, which can be efficiently removed by wet etching to avoid residue affecting the channel patency of the hollow cavity.
[0042] Example 1
[0043] Using silicon wafers as substrate material, hollow cavities 20 are etched into the silicon wafers using methods such as photolithography. High-temperature processing can be used to directly bond the two silicon wafer structures. Precision polishing ensures the horizontality of the silicon wafers, resulting in a substrate with an integral connection channel. Specifically, for the processing requirements of highly heat-sensitive probe materials, a phase change material functional filling layer (such as bismuth-tin alloy or polyethylene glycol) can be selectively filled into the hollow cavity 20 to adjust the coefficient of thermal expansion and alleviate processing thermal stress. For probe materials with good thermal stability, the hollow cavity 20 structure can be directly used for probe 01 processing.
[0044] Example 2
[0045] Using ceramics as raw material, ceramic disks with hollow cavities 20 are prepared through laser engraving, composite electroplating, and 3D printing. Fine polishing yields a substrate with excellent surface flatness. Multilayer ceramics can be laminated to form composite substrates containing interconnected channels.
[0046] Example 3
[0047] Using metal sheets as raw materials, they can be combined with ceramic substrates or multiple metals (such as aluminum-copper composite substrates). The base layer is aluminum, and the upper surface is composite with copper plates. The groove mold is prepared by laser engraving process to form a hollow cavity 20, which takes into account both lightweight and high thermal conductivity.
[0048] The above embodiments can all improve the problems of probe structure damage caused by local thermal stress concentration in traditional femtosecond laser processing, as well as the secondary contamination of processing debris.
[0049] In summary, the composite substrate and its preparation method for femtosecond laser processing probes provided by this invention integrate thermal stress relief and debris removal functions into one, with a simple process flow and high compatibility with femtosecond laser processing systems. No additional auxiliary equipment is required, which can significantly improve probe processing accuracy and yield, and has good industrial application value.
[0050] Obviously, those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.
Claims
1. A composite substrate for femtosecond laser processing probes, characterized in that, It includes a base layer, a hollow cavity, and an optional functional filling layer; the hollow cavity is a three-dimensional mesh hollow structure located inside the base layer, which constitutes an airflow chip removal and plasma suction channel; The functional filling layer is made of phase change material and is selectively filled into the hollow cavity.
2. The composite substrate for femtosecond laser processing probes as described in claim 1, characterized in that, The phase change material is a low-melting-point alloy or an organic phase change material.
3. The composite substrate for femtosecond laser processing probes as described in claim 2, characterized in that, The low-melting-point alloy is a bismuth-tin alloy, and the organic phase change material is polyethylene glycol.
4. The composite substrate for femtosecond laser processing probes as described in claim 1, characterized in that, The substrate material is one of silicon wafers, ceramics, or metal composite materials.
5. The composite substrate for femtosecond laser processing probes as described in claim 4, characterized in that, The metal composite plate is an aluminum-copper composite substrate, wherein the base layer of the aluminum-copper composite substrate is aluminum and the upper surface is composite copper plate.
6. A method for preparing a composite substrate for a femtosecond laser processing probe as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Select a substrate material and use photolithography, deep reactive ion etching, or laser engraving to prepare a mold with a groove structure on the substrate. Step 2: Deposit a sacrificial layer on the inner wall of the groove structure, fill the outer side of the sacrificial layer with silicon nitride or silicon dioxide using chemical vapor deposition to form an intermediate layer, and remove the sacrificial layer by wet etching to obtain a three-dimensional mesh hollow structure with horizontal connectivity, forming the hollow cavity; Step 3: Based on the characteristics of the probe material processed by femtosecond laser, selectively fill the hollow cavity with phase change material to form the functional filling layer; Step 4: Polish the prepared substrate to obtain the composite substrate.
7. The preparation method according to claim 6, characterized in that, In step 1, when the substrate is a silicon wafer, the mold with the groove structure is prepared by photolithography combined with deep reactive ion etching.
8. The preparation method according to claim 6, characterized in that, In step 1, when the base layer is ceramic, the mold with the groove structure is prepared by 3D printing or laser engraving.
9. The preparation method according to claim 6, characterized in that, In step 1, when the base layer is a metal composite plate, the mold with the groove structure is prepared by laser engraving process.
10. The preparation method according to claim 6, characterized in that, In step 2, the sacrificial layer is one of silicon dioxide, polyethylene oxide, aryltriazine polymer, or gel precursor.