Ultrasonic transducer, ultrasonic probe and method for fabricating the same
US7667374B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 23, 2007 |
| Grant date | Feb 23, 2010 |
| Priority date | — |
| Expiry date | Jan 23, 2027 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB06B1/0292
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
In an ultrasonic transducer including a gap between an upper electrode and a lower electrode on a silicon substrate, it is made possible to reduce or adjust warpage of an above-gap membrane vibrated by electrostatic actuation due to internal stress. A fourth insulating film and a fifth insulating film of films positioned above the gap which is a cavity required for transmitting and receiving ultrasonic are respectively a silicon oxide film for compression stress and a silicon nitride film for tensile stress. Therefore, compression stress and tensile stress cancel each other, so that warpage of the above-gap membrane is reduced. An amount of warpage can be adjusted by adjusting a film thickness of the fourth insulating film and a film thickness of the fifth insulating film.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.