Process for verifying a hermetic seal and semiconductor device therefor
US6074891A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 16, 1998 |
| Grant date | Jun 13, 2000 |
| Priority date | — |
| Expiry date | Jun 16, 2018 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB81B2207/097
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and device for verifying whether a cavity (16) enclosing a micromachined sensing structure (14) between a pair of wafers (10, 12) is hermetically sealed by detecting the presence of moisture within the cavity (16). The method entails forming a bare, unpassivated PN junction diode (20) in a semiconductor substrate, preferably a device wafer (10) with the sensing structure (14). The device wafer (10) is then bonded to a capping wafer (12) to enclose the PN junction diode (20) and micromachine (14) within a cavity (16) defined by and between the wafers (10, 12). The reverse diode characteristics of the PN junction diode (20) are then determined by causing a reverse current to flow through the diode (20). For this purpose, either a known voltage is applied across the diode (20) and the reverse leakage current measured, or a known reverse current is forced across the diode (20) and the voltage measured. The unpassivated junction diode (20) exhibits unstable current/voltage readings if sufficient moisture is present within the cavity (16), thereby indicating whether or not the cavity (16) is hermetically sealed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.