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CN-224216199-U - MEMS pressure chip for isolating packaging stress

CN224216199UCN 224216199 UCN224216199 UCN 224216199UCN-224216199-U

Abstract

The utility model discloses an MEMS pressure chip for isolating packaging stress, which comprises a tube shell, wherein an adhesive is fixed at the top end of the tube shell, a silicon support is fixed at the top end of the adhesive, gauge pressure holes are arranged between two groups of tube shells, an upper end expansion joint is arranged at the top end of the interior of the silicon support, a lower end expansion joint is arranged at the bottom end of the interior of the silicon support, and a chip body is arranged at the top end of the silicon support. According to the utility model, the packaging stress is isolated by designing a brand-new support structure on the chip, and meanwhile, the glass support is changed into monocrystalline silicon which is easier to process and consistent with the chip in property, so that the influence of the packaging stress on the sensor is thoroughly eliminated. The thermal expansion stress relief structure is designed to accommodate material expansion and contraction due to temperature changes, preventing overstress and potential damage. These structures typically utilize expansion joints or other design features that allow the material to move freely without constraint, thereby relieving stresses.

Inventors

  • GUAN WEI
  • ZHOU XUAN
  • LI PENGLU

Assignees

  • 武汉中航传感技术有限责任公司

Dates

Publication Date
20260508
Application Date
20250718

Claims (5)

  1. 1. A MEMS pressure die for isolating package stress, comprising: Two groups of tube shells (2) which are symmetrically distributed, and gauge pressure holes (4) are formed between the two groups of tube shells; The silicon support (1) is fixed at the top end of the tube shell (2) through an adhesive (6); A chip body (7) mounted on the top end of the silicon support (1); The upper end expansion joint (3) is arranged at the top end inside the silicon support (1), is square in shape and is matched with the back cavity of the chip body (7); The lower end expansion joint (5) is arranged at the bottom end inside the silicon support (1) and distributed in a ring shape; Wherein, the upper end expansion joint (3) and the lower end expansion joint (5) form a thermal expansion stress release structure.
  2. 2. The MEMS pressure chip for isolating packaging stress as claimed in claim 1, wherein the two sets of tube shells (2) are symmetrically distributed about the central axis of the silicon support (1).
  3. 3. The MEMS pressure chip for isolating packaging stress according to claim 1, wherein the lower expansion joint (5) is a single ring-shaped groove, and the ring-shaped circle center is positioned at the geometric center of the silicon support (1).
  4. 4. The MEMS pressure chip for isolating packaging stress as claimed in claim 1, wherein the square outline of the upper end expansion joint (3) is coincident with the projection outline of the back cavity of the chip body (7).
  5. 5. The MEMS pressure chip for isolating packaging stress according to claim 1, wherein the annular design of the lower expansion joint (5) is that any point on the joint surface of the silicon support (1) and the tube shell (2) is met, and the connecting line pointing to the annular center coincides with the normal direction from the point to the annular outline.

Description

MEMS pressure chip for isolating packaging stress Technical Field The utility model relates to the technical field of MEMS pressure chips, in particular to an MEMS pressure chip for isolating packaging stress. Background The structure and packaging of conventional piezoresistive pressure sensors are mature and fixed, the back of the chip is usually a flat glass support, and then the chip is bonded to a stainless steel tube base using silicone or epoxy. Due to the different coefficients of thermal expansion of the adhesive and the chip, thermal stress mismatch will cause drift in the sensor output when temperature changes. In addition, the adhesive absorbs moisture from the environment causing localized expansion, further increasing the package stress. Thus reducing or eliminating the effects of unpredictable package stresses caused by the adhesive is a problem that piezoresistive pressure sensors need to address in packaging. Current research and practice show that adhesives with smaller young's modulus and smaller thermal expansion coefficient can effectively reduce the packaging stress, but cannot completely avoid the generation of the packaging stress. The stress isolation structure is designed on the pressure chip, so that the packaging stress caused by chip bonding can be avoided. At present, the packaging stress is reduced mainly by selecting an adhesive (chip adhesive) with better performance. However, in the field of micro-pressure measurement, reduced package stress still has a large impact on sensor performance. We have therefore proposed a MEMS pressure chip that isolates package stress to ameliorate the above problems. Disclosure of utility model The utility model aims to provide a MEMS pressure chip for isolating packaging stress, which is used for solving the problem that the packaging stress affects the performance of a sensor in the background technology. In order to achieve the above purpose, the utility model provides a MEMS pressure chip for isolating packaging stress, comprising: Two sets of tube shells which are symmetrically distributed, wherein gauge pressure holes are formed between the two sets of tube shells; the silicon support is fixed at the top end of the tube shell through an adhesive; The chip body is arranged at the top end of the silicon support; The upper end expansion joint is arranged at the top end inside the silicon support, is square in shape and is matched with the back cavity of the chip body; the lower end expansion joint is arranged at the bottom end inside the silicon support and distributed in a ring shape; Wherein, upper end expansion joint and lower extreme expansion joint constitute thermal expansion stress relief structure. As a preferred solution, the two sets of shells are symmetrically distributed about the central axis of the silicon support. As a preferable technical scheme, the expansion joint at the lower end is a single-ring groove, and the ring center of the circle is positioned at the geometric center of the silicon support. As a preferable technical scheme, the square outline of the expansion joint at the upper end is coincident with the projection outline of the back cavity of the chip body. As a preferable technical scheme, the annular design of the expansion joint at the lower end meets the requirement that any point on the joint surface of the silicon support and the pipe shell is coincident with the normal direction from the point to the annular outline by the connecting line pointing to the annular center. Compared with the prior art, the utility model has the beneficial effects that the packaging stress is isolated by designing a brand new support structure on the chip, and meanwhile, the glass support is changed into monocrystalline silicon which is easier to process and consistent with the chip in property, so that the influence of the packaging stress on the sensor is thoroughly eliminated. The thermal expansion stress relief structure is designed to accommodate material expansion and contraction due to temperature changes, preventing overstress and potential damage. These structures typically utilize expansion joints or other design features that allow the material to move freely without constraint, thereby relieving stresses. Drawings FIG. 1 is a schematic elevational view of the present utility model; FIG. 2 is a schematic diagram of a gauge pressure hole in cross-section in elevation in accordance with the present utility model; FIG. 3 is a schematic diagram of the front cross-sectional structure of the expansion joint at the lower end of the utility model; fig. 4 is a schematic diagram of a front view of a chip according to the present utility model. In the figure, 1, a silicon support, 2, a tube shell, 3, an upper end expansion joint, 4, a gauge pressure hole, 5, a lower end expansion joint, 6, an adhesive and 7, a chip body. Detailed Description The following description of the embodiments of the present utility model will be made