Asia Pacific Microsystems, Inc.

Ricktek Technology Corporation

Hung-Dar Wang

Shih-Chin Gong

Chung-Yang Tseng

Pei-Cheng Huang

Chang-Chih Lin

Ruey-Shing Huang

Reuy-shing Huang

Tong-An Lee

Kuo-Chung Chan

A driving circuit for a sound outputting apparatus includes a H-bridge and a charge pump established by six switches for driving two types of loudspeakers, respectively. The six switches include two common switches to be configured in the H-bridge and the charge pump, thereby reducing the costs and circuit area of the driving circuit.

Driving circuit for a sound outputting apparatus

A method of maintaining photolithographic precision alignment for a wafer after being bonded, wherein two cavities are formed at the rear surface of a top wafer at the position corresponding to alignment marks made on a bottom wafer. The depth of both cavities is deeper than that of a final membrane structure. The top wafer is then bonded to the bottom wafer which already has alignment marks and a microstructure. This bonded wafer is annealed to intensify its bonding strength. After that, a thinning process is applied until the thickness of the top wafer is reduced to thinner than the cavity depth such that the alignment marks are emerged in the top wafer cavities thereby serving as alignment marks for any exposure equipment.

Method of maintaining photolithographic precision alignment after wafer bonding process

A measurement method for the thinned thickness of the silicon wafer, wherein thickness inspection patterns are fabricated onto the silicon wafer substrate by anisotropic etching, and then the wafer is polished with a polisher; thus a wafer with desired thickness can be obtained after the polish is proceeded; the thickness of the upper wafer is determined by the said inspection patterns, then the wafer is sorted by thickness; thus it can be applied to the MEMS micromachined devices that in need of the wafer with such precise thickness.

Fabrication process for bonded wafer precision layer thickness control and its non-destructive measurement method

The present invention relates to a silicon pressure sensor that in need of three strips of piezoresistors on each side and the manufacturing method thereof; wherein, the impurity concentration of the piezoresistors are about 10cmin order to reduce the influence of temperature; the lead between the piezoresistors (namely the internal connection lead) is a highly-doping interconnect (about 10cm) fabricated along the direction with minimum piezoresistance coefficient; with regard to the connection circuit for connecting the piezoresistors with the external Wheatstone bridge circuit (namely the external connection circuit), of which one end near the inner side of the membrane is also fabricated along the direction with minimum piezoresistance coefficient, and another end of the lead near the edge of the membrane is a interconnect that is perpendicular to the diaphragm, and is connected out to the external circuit; with this structure, the four resistors of the Whetstone bridge are balanced and symmetrized, thus the zero offset caused by the variations in resistance of the bridge can be reduced in order to simplify the signal-processing circuit.

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Kaohsiung, Taiwan

Hung-Dar Wang