A collapsible ring-shaped sealed gas cavity structure with micro support columns

Abstract

The application discloses a kind of anti-collapse annular sealed gas cavity structures with micro support column, belong to airtight packaging technical field.The structure is evenly arranged with micro insulation support column in the radial section of annular sealed gas cavity in equilateral triangle or square array, support column diameter is 10~20 μm, interval is 200~500 μm, and is integrally etched into shape with the same silicon-based wafer as annular gas cavity.The application can effectively resist 0.1~2.0MPa internal and external pressure difference, avoid gas cavity deformation and collapse, while gas circulation resistance is small, and there is no obvious additional wind resistance;Homogeneous material design is adopted, the thermal expansion coefficient is matched, the long-term reliability is high, the process is simple, and is suitable for three-dimensional stacked chip heat dissipation, power semiconductor packaging, MEMS device and other various scenes.

Description

Technical Field

[0001] This invention belongs to the field of chip hermetically sealed packaging and MEMS device vacuum packaging technology. Specifically, it relates to an annular sealed gas cavity structure with built-in micro insulating support pillars, which can resist atmospheric pressure and high pressure difference and prevent gas cavity deformation and collapse. It is suitable for three-dimensional stacked chip gas heat dissipation packaging, power semiconductor hermetically sealed packaging, micro sensor gas cavity and other scenarios. Background Technology

[0002] With the development of semiconductor and MEMS technologies, annular sealed gas cavities are widely used in gas heat dissipation, vacuum packaging, and gas sensing. Existing annular sealed gas cavities generally employ thin-walled cavity structures, and the pressure difference between the external atmospheric pressure and the internal gas pressure can easily cause the cavity to collapse inward.

[0003] Simulation results show that under 1 standard atmosphere, the maximum deformation of the central region of a traditional unsupported annular gas cavity can reach more than 50 μm, resulting in a reduction of more than 30% in the cross-sectional area of ​​the gas channel. This can lead to a 40% decrease in heat dissipation efficiency in gas heat dissipation scenarios and performance drift or even failure in vacuum packaging scenarios. During long-term use, repeated temperature cycles will exacerbate the deformation, eventually causing fatal problems such as channel blockage and seal failure, which cannot meet the long-term reliability requirements of more than 10 years. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an anti-collapse annular sealed gas cavity structure with micro support columns. By integrally etching micro insulating support columns inside the gas cavity, the structural strength of the gas cavity is greatly improved without affecting gas circulation, thus solving the problems of easy collapse and poor reliability of traditional gas cavities.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows.

[0006] A collapse-resistant annular sealed air cavity structure with micro-support columns includes an annular sealed air cavity. Within the radial cross-section of the annular sealed air cavity, a plurality of micro-insulating support columns are uniformly arranged in an equilateral triangular or square array. The axis of the support columns is perpendicular to the upper and lower bottom surfaces of the air cavity, with a diameter of 10-20 μm and a center-to-center distance of 200-500 μm between adjacent support columns. The micro-insulating support columns and the annular sealed air cavity are integrally etched and formed using the same silicon-based wafer, and can withstand an internal and external pressure difference of 0.1-2.0 MPa. Beneficial effects

[0007] Significantly improved resistance to collapse: Under a high pressure difference of 1.5MPa, the maximum deformation of the air cavity of the structure of this invention is ≤2μm, which is far lower than the 50μm of the traditional unsupported structure, thus completely solving the problems of air cavity collapse and channel blockage.

[0008] No significant loss of gas flow: By optimizing the diameter and spacing parameters of the support columns, the gas circulation pressure loss is ≤5Pa, which is less than 3% different from that of the unsupported air chamber. There is no additional wind resistance and it does not affect the overall performance of the system.

[0009] High long-term reliability: The support pillars are made of single-crystal silicon material that is the same as the silicon-based wafer body. The coefficient of thermal expansion is perfectly matched. After 1,000 temperature cycles of -40℃ to 125℃, the sealing leakage rate has not changed significantly, and the structure has not cracked or collapsed.

[0010] Simple process and low cost: The support column and air cavity are etched together in one piece, without the need for additional assembly steps. It is perfectly adapted to wafer-level mass production and reduces manufacturing costs by more than 20%.

[0011] High versatility: It can be independently applied to all scenarios that require annular sealed gas cavities, including but not limited to gas heat dissipation of three-dimensional stacked chips, gas sealing of power modules, MEMS vacuum sensors, microfluidic chips, etc. Attached Figure Description

[0012] Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 is a partial enlarged view of the micro insulating support column, showing the equilateral triangular array arrangement structure; Explanation of reference numerals: 1 - annular sealed air cavity; 3 - micro insulating support column; 4 - vertical microporous heat-conducting array. Detailed Implementation

[0013] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0014] Example 1 (Low-pressure scenario, applicable to working pressure of 0.1~0.5MPa) The anti-collapse annular sealing gas cavity structure with micro support columns provided in this embodiment has an internal height of 50 μm and a radial width of 50 μm. Micro insulating support columns (3) are uniformly arranged in a square array inside. The support columns have a diameter of 10 μm, a center-to-center distance of 500 μm between adjacent support columns, and a height equal to the internal height of the gas cavity. The support columns are made of single-crystal silicon material, which is homogeneous with the silicon-based wafer body and is integrally etched and formed with the annular sealing gas cavity (1). The annular sealing gas cavity (1) is sealed at the wafer level using an anodic bonding process. The bonding ring width is 50 μm, and the sealing leakage rate is ≤10⁻¹¹ mbar・L / s.

[0015] This embodiment is applicable to scenarios such as MEMS microsensor gas chambers and low-pressure gas packaging.

[0016] Example 2 (Medium pressure scenario, applicable to working pressure of 0.5~1.0MPa, preferred solution) The difference between this embodiment and Embodiment 1 is that: the internal height of the annular sealed gas cavity (1) is 100μm and the radial width is 80μm; the micro insulating support columns (3) are arranged in an equilateral triangular array with a diameter of 15μm, the center-to-center distance between adjacent support columns is 300μm, and the cross-section is a regular hexagon; the gold-gold hot-press bonding process is adopted, the bonding temperature is 280℃, the pressure is 5MPa, the bonding time is 5 minutes, and the bonding ring width is 100μm; the annular sealed gas cavity (1) and the vertical micro-hole heat conduction array (4) are etched and formed by the same silicon-based wafer, and together they form a connected gas flow channel.

[0017] This embodiment is applicable to gas heat dissipation packaging of three-dimensional stacked chips. It can be integrally etched and formed with the vertical micro-hole thermal array (4) to jointly form a gas heat dissipation circuit.

[0018] Example 3 (High-pressure scenario, applicable to working pressure of 1.0~2.0MPa) The difference between this embodiment and embodiment 1 is that: the internal height of the annular sealing gas cavity (1) is 200μm and the radial width is 1000μm; the micro insulating support columns (3) are arranged in an equilateral triangle array with a diameter of 20μm and a center-to-center distance of 200μm between adjacent support columns; the glass slurry sealing process is adopted and the bonding ring width is 150μm.

[0019] This embodiment is applicable to scenarios such as hermetically sealed packaging of high-power semiconductor modules and high-pressure gas cooling systems.

Claims

1. A collapse-resistant annular sealed air cavity structure with micro-support columns, characterized in that, The system includes an annular sealed air cavity (1), in which a plurality of miniature insulating support columns (3) are uniformly arranged in an equilateral triangle or square array within the radial cross section of the annular sealed air cavity (1). The axis of the miniature insulating support column (3) is perpendicular to the upper and lower bottom surfaces of the annular sealed air cavity (1), and its diameter is 10~20μm. The center-to-center distance between adjacent support columns is 200~500μm. The miniature insulating support column (3) and the annular sealed air cavity (1) are integrally etched and formed using the same silicon-based wafer to resist the internal and external pressure difference of 0.1~2.0MPa and prevent the air cavity from deforming and collapsing.

2. The anti-collapse annular sealed air cavity structure with micro-support columns according to claim 1, characterized in that, The internal height of the annular sealed air cavity (1) is 50~200μm, and the radial width is 50~1000μm.

3. The anti-collapse annular sealed air cavity structure with micro-support columns according to claim 1, characterized in that, The micro insulating support column (3) is made of single-crystal silicon material and is homogeneous with the silicon-based wafer body.

4. The anti-collapse annular sealed air cavity structure with micro-support columns according to claim 1, characterized in that, The height of the miniature insulating support column (3) is equal to the internal height of the annular sealed air cavity (1), and its upper and lower ends are integrally connected to the upper and lower walls of the annular sealed air cavity (1), respectively.

5. The anti-collapse annular sealed air cavity structure with micro-support columns according to claim 1, characterized in that, The cross-section of the miniature insulating support column (3) is circular, hexagonal, or square, with hexagonal being the preferred shape.

6. The anti-collapse annular sealed air cavity structure with micro-support columns according to claim 1, characterized in that, The array arrangement of the micro insulating support pillars (3) does not obstruct the gas circulation flow in the annular sealed gas cavity (1). Under the commonly used working flow rate of 1~5m / s for chip gas heat dissipation, the gas circulation pressure loss is ≤5Pa.

7. The anti-collapse annular sealed air cavity structure with micro-support columns according to claim 1, characterized in that, The annular sealing gas cavity (1) adopts a wafer-level single-ring sealing process with a sealing leakage rate of ≤10⁻¹¹mbar・L / s.

8. The anti-collapse annular sealed air cavity structure with micro-support columns according to claim 1, characterized in that, The wafer-level single-ring seal employs gold-gold hot-press bonding, anodic bonding, eutectic bonding, or glass slurry sealing processes, with a bonding ring width of 50~150μm.

9. The anti-collapse annular sealed air cavity structure with micro-support columns according to claim 1, characterized in that, The annular sealed gas cavity (1) and the vertical micro-hole heat conduction array (4) are integrally etched and formed on the same silicon-based wafer, together forming a connected gas flow channel.

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