Method of making transducer

• US 4,293,373 A
• Filed: 02/26/1980
• Issued: 10/06/1981
• Est. Priority Date: 05/30/1978
• Status: Expired due to Term

• Current Assignee: International Standard Electric Corporation (ITT, Inc.)
• Original Assignee: International Standard Electric Corporation (ITT, Inc.)
• Inventors: Greenwood, John C.
• Primary Examiner(s): Powell, William A.
• Application Number:
  US06/124,781
• Time in Patent Office: 588 Days
• Field of Search: 156/628, 156/647, 156/648, 156/649, 156/651, 156/657, 156/662, 156/650, 156/659.1, 156/654, 148/1.5, 148/187, 29/580, 29/594, 29/595, 29/602 A, 29/610 SG, 338/2, 338/4, 338/47, 74/704, 74/726, 74/754, 252/79.1
• US Class Current: 438/53
• CPC Class Codes: G01L 9/0019 of a semiconductive element
• CPC Class Codes: G01L 9/0042 Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively
• CPC Class Codes: H01L 29/84 controllable by variation of applied mechanical force, e.g. of pressure
• CPC Class Codes: Y10S 438/928 Front and rear surface processing

Abstract

A silicon transducer including a silicon frame with one or more lands extending from a diaphragm or the like. The lands are interconnected by two thin strips formed integrally with the lands. The strips are essentially the transducer. The transducer is constructed by etching a boron doped wafer with a mixture of catechol, ethylene diamine and water.

Claims

1. The method of making a silicon pressure transducer, said method comprising the steps of:

selectively boron doping both faces of a silicon wafer;

etching one face of said wafer to define a cavity within a frame forming a closed loop and two lands spaced from each other and from said frame, said diaphragm connecting said lands; and

selectively etching the other face of said wafer opposite said groove so as to define a silicon diaphragm to which both of said lands are fixed, said etching steps leaving at least two filaments having a first pair of adjacent ends fixed to one land and a second pair of adjacent ends fixed to the other land in a plane spaced from said diaphragm.

2. A process as claimed in claim 1, in which said selective etching is effected with a mixture of catechol, ethylene diamine and water.