Corrosion-proof pressure transducer

• US 6,584,853 B2
• Filed: 10/12/2001
• Issued: 07/01/2003
• Est. Priority Date: 10/12/2001
• Status: Expired due to Term

• Current Assignee: Kavlico Corporation (Sensata Technologies Holding Plc)
• Original Assignee: Kavlico Corporation (Sensata Technologies Holding Plc)
• Inventors: Park, Kyong M., Nassar, Marcos A.
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): FERGUSON SAMRETH, MARISSA LIANA
• Application Number:
  US09/977,931
• Publication Number:
  US 20030070489A1
• Time in Patent Office: 627 Days
• Field of Search: 737/54, 731/16, 731/17, 731/172, 731/173, 731/181, 257/254, 257/257, 361/283, 123/568.16, 123/676, 602/77, 602/88, 701/101
• US Class Current: 73/754
• CPC Class Codes: G01L 19/147 Details about the mounting of the sensor to support or covering means
• CPC Class Codes: G01M 15/106 using pressure sensors
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

A corrosion proof pressure transducer for measuring exhaust gas pressure includes a chip with a semiconductive diaphragm, electronics, and conductive pads thereon; with leads sonically bonded to the pads. To preclude degradation of the transducer by internal combustion engine exhaust gases, the chip may have (1) a thin glass passivation layer, (2) a vacuum deposited polymeric coating and (3) a layer of gel, thereon.

Claims

1. A corrosion proof pressure transducer system comprising:

an automobile having an exhaust system;

a pressure transducer mounted to sense the pressure in said exhaust system;

said pressure transducer including a chip having a semiconductive diaphragm and conductive pads thereon;

electrical circuitry mounted on said chip coupled to diaphragm, and said conductive pads;

wires sonically bonded to said conductive pads;

said chip having a glass passivation coating thereon;

said glass passivation coating being in intimate contact with the upper surface of said chip and the circuitry on said chip;

a vacuum deposited polymeric dielectric coating extending over the glass coated chip including the conductive pads; and

sealing the upper surface thereof; and

a layer of gel material overlying said chip;

whereby possible pin holes in the glass coating or cracks in the conductive pads are sealed against the corrosive exhaust gases of said exhaust system.

2. A system as defined in claim 1 wherein said gel material extends over said chip and said polymeric coating.

3. A system as defined in claim 1 wherein another vacuum formed polymeric coating overlies said layer of gel material.

4. A corrosion proof pressure transducer system comprising:

an automobile having an exhaust system;

a pressure transducer mounted to sense the pressure in said exhaust system;

said pressure transducer including a chip having a semiconductive diaphragm and conductive pads thereon;

wires sonically bonded to said conductive pads;

said chip having a glass passivation coating thereon;

said glass passivation coating being in intimate contact with the upper surface of said chip and the circuitry on said chip; and

a sealing dielectric coating extending over the glass coated chip including the conductive pads; and

sealing the upper surface thereof;

whereby possible pin holes in the glass coating or cracks in the conductive pads are sealed against the corrosive exhaust gases of said exhaust system.

5. A system as defined in claim 4 further comprising gel material extending over said chip.

6. A system as defined in claim 4 further comprising electronic components mounted on said chip.

7. A corrosion proof pressure transducer system comprising:

a pressure transducer including a chip having a semiconductive diaphragm and conductive pads thereon;

gel material extending over said chip;

wires sonically bonded to said conductive pads;

said chip having a glass passivation coating thereon;

said glass passivation coating being in intimate contact with the upper surface of said chip and the circuitry on said chip;

a vacuum deposited polymeric dielectric coating extending over the glass coated chip including the conductive pads; and

sealing the upper surface thereof;

whereby possible pin holes in the glass coating or cracks in the conductive pads are sealed against adverse environmental conditions.

8. A corrosion proof pressure transducer system comprising:

said pressure transducer including a chip having a flexible diaphragm and conductive pads thereon;

electrical circuitry mounted on said chip coupled to diaphragm and said conductive pads;

wires bonded to said conductive pads;

a sealing polymeric dielectric coating extending over the chip including the conductive pads; and

sealing the upper surface thereof; and

an additional protective layer overlying said chip;

whereby said chip is sealed against adverse environmental conditions.

9. A system as defined in claim 8 wherein gel material extends over said chip and said polymeric coating.

10. A system as defined in claim 8 wherein a vacuum formed polymeric coating overlies said layer of gel material.

11. A system as defined in claim 8 wherein said chip is coated with a very thin glass passivation coating;

said glass passivation coating being in intimate contact with the upper surface of said chip and the circuitry on said chip.

12. A system as defined in claim 8 wherein said system includes a layer of gel overlying said chip.

13. A system as defined in claim 8 wherein said diaphragm is formed of semiconductive material.