Calvin K Choi

US Patent:

20110101525, May 5, 2011

Filed:

Oct 30, 2009

Appl. No.:

12/610148

Inventors:

Deva Pattanayak - Saratoga CA, US
King Owyang - Atherton CA, US
Mohammed Kasem - Santa Clara CA, US
Kyle Terrill - Santa Clara CA, US
Reuven Katraro - Rishon Lezion, IL
Kuo-In Chen - Los Altos CA, US
Calvin Choi - San Jose CA, US
Qufei Chen - San Jose CA, US
Ronald Wong - Millbrae CA, US
Kam Hong Lui - Santa Clara CA, US
Robert Xu - Fremont CA, US

Assignee:

VISHAY-SILICONIX - Santa Clara CA

International Classification:

H01L 23/48
H01L 23/488
H01L 21/768

US Classification:

257738, 257763, 438615, 257213, 257E21575, 257E23011, 257E23023

Abstract:

A semiconductor device (e.g., a flip chip) includes a substrate layer that is separated from a drain contact by an intervening layer. Trench-like feed-through elements that pass through the intervening layer are used to electrically connect the drain contact and the substrate layer when the device is operated.

US Patent:

54867720, Jan 23, 1996

Filed:

Jun 30, 1994

Appl. No.:

8/268755

Inventors:

Fwu-Iuan Hshieh - Saratoga CA
Calvin K. Choi - San Jose CA
William H. Cook - Fremont CA
Lih-Ying Ching - Cupertino CA
Mike F. Chang - Cupertino CA

Assignee:

Siliconix Incorporation - Santa Clara CA

International Classification:

G01R 3126

US Classification:

324769

Abstract:

The present invention detects defects near the gate/trench-surface interface of trench transistors. Defects near this interface which cause long term reliability problems generally also result in charges being trapped near the interface. In accordance with one embodiment of the present invention, a negative voltage is applied to the gate of the trench transistor with its drain grounded and its source floating. A leakage current flowing between the gate and drain is measured as a function of the voltage applied to the gate. A transistor whose gate-drain leakage current exceeds a predetermined value at a specified gate voltage is deemed to be defective. In another embodiment of the present invention, the gate-drain leakage current is measured as described above and monitored over time. Charge accumulated near the gate-drain interface due to defects in the interface results in the gate-drain leakage current taking a longer period of time to fall off to its steady state value. Accordingly, if the leakage current of a particular trench transistor does not fall off to a predetermined value within a predetermined amount of time, the transistor is deemed to be defective.

US Patent:

55857361, Dec 17, 1996

Filed:

Nov 29, 1994

Appl. No.:

8/346037

Inventors:

Fwu-Iuan Hshieh - Saratoga CA
Calvin Choi - Pleasanton CA

International Classification:

G01R 3102

US Classification:

324754

Abstract:

A contact probe for semiconductor in-line process monitoring or device measurement is disclosed in this invention which uses gallium, indium or any low-melting and low-vapor pressure electrically conductive alloy as a contact probing material. The probe can be used to directly measure mobile ion density without requiring the formation of aluminum dots on the semiconductor wafers. The safety issues caused by high temperature operation are also eliminated. The time requirement for process-equipment qualification is significantly reduced because the preparation time for aluminum dot formation is now eliminated. In comparison to the mercury probes, since in this invention, the contact is formed at high temperature thus leading to better contacts between the probe and the wafer, which in turn resulting in higher measurement accuracy. Furthermore, the conventional pin slip problem during elevated temperature stress is eliminated by the use of the contact probe of this invention. The device disclosed in this invention includes a metal tube or cylinder surrounded by heating element.