The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 15, 2002
Filed:
Jan. 05, 2001
Wen H. Ko, Cleveland Heights, OH (US);
Qiang Wang, San Jose, CA (US);
Other;
Abstract
Manufacturing all-silicon force sensors, such as capacitive pressure sensors ( ) that have long term stability and good linear sensitivity, and can be built into of a pneumatic tire. The sensors include buried electrical feedthrough ( ) to provide an electrical connection into a sealed silicon cavity ( ). The buried feedthrough consists of a conductor ( ) in a shallow groove ( ) in a substrate ( ), communicating between the sensing cavity ( ) and an external contact area ( ). The sensor designs also feature a method for forming a silicon-to-silicon fusion bond (SFB) wherein at least one of the two surfaces ( ) to be has a tough silicon surface unsuitable for good SFB joints because it was bonded heavily boron-doped by means of diffusion. The method of this invention includes preparing each doped surface ( ) for SFB by polishing the surface with a Chemical-Mechanical Polishing (CMP) process. The sensor designs can also include optional reference capacitors ( ) on the same chip ( ) as the sensing capacitor ( ). The reference capacitors ( ) are insensitive to pressure (force), but respond to ambient temperature changes in the same way as the sensing capacitor. Suitable external interface circuits can utilize the reference capacitors ( ) to pull out the majority of ambient temperature effects.