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CN-116989933-B - MEMS pressure sensor oil filling core suitable for high-pressure small molecular medium

CN116989933BCN 116989933 BCN116989933 BCN 116989933BCN-116989933-B

Abstract

The invention belongs to the field of pressure sensors, in particular to an MEMS pressure sensor oil filling core suitable for high-pressure small molecular media, the pressure-sensitive ceramic consists of a compression ring, a corrugated diaphragm, a core base, sealing steel balls, silicone oil, a ceramic seat, a pressure chip, a lead wire and other parts which are positioned in a sealing cavity formed by the corrugated diaphragm and the core base. The invention aims at the defects of the traditional MEMS pressure sensor oil filling core body, improves the design from the multi-position structure process, solves the problems of small molecular medium infiltration, lead fracture failure, high-pressure connection sealing and the like, and is particularly suitable for the accurate measurement of the pressure of high-pressure small molecular medium.

Inventors

  • FENG YINGHENG
  • ZHANG JINHAO
  • WANG LU
  • XIANG LU
  • LIU QIANG
  • CHEN FENG

Assignees

  • 中电科芯片技术(集团)有限公司

Dates

Publication Date
20260505
Application Date
20230801

Claims (6)

  1. 1. The MEMS pressure sensor oil filling core suitable for the high-pressure small molecular medium is characterized by comprising a compression ring (1), a corrugated diaphragm (2), a core base (3), a sealing steel ball (4), silicone oil (5), a ceramic seat (6), a pressure chip (7) and a lead (8), wherein the silicone oil (5), the ceramic seat (6), the pressure chip (7) and the lead are positioned in a sealing cavity formed by the corrugated diaphragm (2) and the core base (3); The top of the core base (3) is provided with a cavity, the pressure ring (1) presses the corrugated diaphragm (2) at the upper end of the cavity at the top of the core base (3), and the pressure ring (1), the corrugated diaphragm (2) and the core base (3) are sealed by laser welding, so that a sealing cavity is formed between the corrugated diaphragm (2) and the core base (3); The bottom of the cavity of the core base (3) is provided with a plurality of through holes and an oil filling hole from the bottom of the core base (3), pins are sintered in the through holes through glass, the oil filling hole is of a counter bore structure, and after silicone oil (5) is injected, the silicone oil is pre-pressed in the counter bore structure through a sealing steel ball (4) and then subjected to laser welding sealing; The ceramic base (6) is of a circular ring structure and is fixed at the bottom of a cavity of the core base (3) through structural adhesive, a boss (63) is arranged on the front surface of the ceramic base (6), a plurality of through holes and an oil filling hole are formed in the front surface of the ceramic base (6), the sizes and positions of the plurality of through holes and the oil filling hole which are formed in the core base (3) correspond to those of the plurality of through holes and the oil filling hole which are formed in the core base (3), a plurality of cup-shaped adhesive filling holes (61) are formed in the boss (63) and are adjacent to the plurality of through holes which are formed in the front surface of the ceramic base (6), and a plurality of adhesive flow holes (62) are formed in the bottom of the plurality of cup-shaped adhesive filling holes (61); the ceramic die is characterized in that a circular or rectangular sinking table is arranged at the center of the bottom of the cavity of the core base (3), the pressure chip (7) is placed in a circular ring structure of the ceramic base (6) and fixed in the sinking table at the center of the bottom of the cavity of the core base (3) through chip adhesive, the lead (8) spans a cup-shaped glue injection hole (61) on the boss (63) to connect an electrode on the pressure chip (7) with a pin in a through hole of the core base (3), and the lead (8) is fixed by injecting structural adhesive into the cup-shaped glue injection hole (61).
  2. 2. The MEMS pressure sensor oil filling core suitable for high-pressure small molecular media according to claim 1, wherein the two sides of the corrugated diaphragm (2) are subjected to gold plating treatment, and the thickness of single-sided gold plating is 2um.
  3. 3. MEMS pressure sensor oil filling core suitable for high pressure small molecule media according to claim 1 characterized in that the core base (3) profile has connecting threads and flange features.
  4. 4. The MEMS pressure sensor oil filling core suitable for the high-pressure small molecular medium according to claim 1, wherein the deposition table of the center of the bottom of the cavity of the core base (3) is slightly larger than the bonding area of the pressure chip (7), and the depth of the deposition table is 0.1-0.2 mm.
  5. 5. The MEMS pressure sensor oil filling core suitable for high-pressure small molecular medium according to claim 1, wherein a bottom sinking table (64) is arranged on the back surface of the ceramic base (6), and the structural adhesive injected into the front cup-shaped adhesive injection hole (61) flows into the bottom sinking table (64) through the adhesive flow hole (62) to form an i-shaped bonding structure with the structural adhesive of the fixed ceramic base (6).
  6. 6. The MEMS pressure sensor oil filling core suitable for the high-pressure small molecular medium according to claim 1, wherein the MEMS pressure sensor oil filling core is in threaded connection with the MEMS pressure sensor body structure, and after the pressure ring (1) is subjected to primary sealing by red copper gasket prepressing, the flange surface of the MEMS pressure sensor oil filling core and the MEMS pressure sensor body are subjected to secondary sealing by laser welding, so that a stable sealing connection structure is formed.

Description

MEMS pressure sensor oil filling core suitable for high-pressure small molecular medium Technical Field The invention belongs to the field of pressure sensors, and particularly relates to an MEMS pressure sensor oil filling core suitable for a high-pressure small molecular medium. Background MEMS (Micro-Electro-MECHANICAL SYSTEM, micro-electromechanical system) pressure sensors are widely applied to the fields of aerospace, petrochemical industry, industrial control, instruments and meters and the like, and can convert external pressure signals into electric signals so as to realize accurate measurement of external pressure. MEMS pressure sensors generally consist of a structural housing, a pressure core, which is the core sensing unit of the MEMS pressure sensor, and a signal processing circuit. The oil-filled isolation package is a common package form of the MEMS pressure sensor, and the MEMS pressure chip is not directly contacted with external measuring media when the package is adopted, is insensitive to the physical and chemical properties of the measuring media, and is therefore commonly used for pressure measurement in severe environments. The pressure core products on the market at present are rich in variety and more in style, basically meet the domestic market demands, but most of the range coverage ranges of the pressure cores are between 0MPa and 40MPa, and domestic researches on high-pressure cores above 40MPa are less. In the fields of aerospace and the like, pressure measurement is required to be carried out on small molecular gases such as hydrogen (H2), helium (He) and the like in a high-pressure environment, and as the gases can easily permeate through a corrugated membrane and are mixed with silicone oil, the volume expansion of the silicone oil generates redundant stress to reduce the output signal precision of a pressure core body, so that the application of the MEMS pressure sensor in the environment is influenced. Meanwhile, the pressure sensor applied to the aerospace field needs to be subjected to severe environment tests such as high-frequency vibration, high-speed impact and the like. Because the two ends of the lead are fixed by the bonding process only in the conventional pressure core body, the bonded lead is arched and soaked in silicone oil, and certain stress exists, so that the risk of fracture and bonding failure exists in high-frequency vibration and high-speed impact environments. Disclosure of Invention In order to solve the problems in the prior art, the invention provides an MEMS pressure sensor oil filling core suitable for a high-pressure small molecular medium, which comprises a compression ring (1), a corrugated membrane (2), a core base (3), a sealing steel ball (4), and silicone oil (5), a ceramic base (6), a pressure chip (7) and a lead (8) which are positioned in a sealing cavity formed by the corrugated membrane (2) and the core base (3); The top of the core base (3) is provided with a cavity, the pressure ring (1) presses the corrugated diaphragm (2) at the upper end of the cavity at the top of the core base (3), and the pressure ring (1), the corrugated diaphragm (2) and the core base (3) are sealed by laser welding, so that a sealing cavity is formed between the corrugated diaphragm (2) and the core base (3); The bottom of the cavity of the core base (3) is provided with a plurality of through holes and an oil filling hole from the bottom of the core base (3), pins are sintered in the through holes through glass, the oil filling hole is of a counter bore structure, and after silicone oil (5) is injected, the silicone oil is pre-pressed in the counter bore structure through a sealing steel ball (4) and then subjected to laser welding sealing; The ceramic base (6) is of a circular ring structure and is fixed at the bottom of a cavity of the core base (3) through structural adhesive, a boss (63), a plurality of through holes and an oil injection hole are formed in the front of the ceramic base (6), the plurality of through holes and the oil injection hole which are formed in the front of the ceramic base (6) correspond to the plurality of through holes and the oil injection hole which are formed in the core base (3) in size and position, a plurality of cup-shaped adhesive injection holes (61) are formed in the boss (63) and are adjacent to the plurality of through holes which are formed in the front of the ceramic base (6), and a plurality of adhesive flow holes (62) are formed in the bottom of the cup-shaped adhesive injection holes (61); the ceramic die is characterized in that a circular or rectangular sinking table is arranged at the center of the bottom of the cavity of the core base (3), the pressure chip (7) is placed in a circular ring structure of the ceramic base (6) and fixed in the sinking table at the center of the bottom of the cavity of the core base (3) through chip adhesive, the lead (8) spans a cup-shaped glue injection hole (61) on the bos