Taiwan Semiconductor Manufacturing Comp. Ltd.

Dean E Lin

Cheng-Yu Chu

Chih Ming Chen

Yi-Jing Chu

Jenq-Dong Sheu

Chien K Chou

A metal code process for a read-only memory (ROM) combines the alignment dip back process (to reduce the polyoxide thickness over the gate electrode and to protect the field oxide) with a double charge implant approach to provide the function of a depletion mode ROM cell. The alignment dip back process also avoids leakage current problems. A stable depletion mode device character is achieved by implant step energies greater than 150 keV.

Alignment dip back oxide and code implant through poly to approach the depletion mode device character

The invention provides a vacuum pencil having an abutment pin which limits the distance the tip of the vacuum pencil can extend past the edge of a wafer thus reducing scratches on the device sides of adjacent wafers. The vacuum pencil has a relatively flat tip connected to a body. The tip has a flat top side for engaging a wafer. The top side of the tip has channels for delivering a vacuum to seal against the wafer against the tip. The top side of the tip also has an pin mounted between the channels and the body. A passage for delivering a vacuum runs through the body and the channel is connected to the channel in the tip. The pin can be a pentagon shaped pin which is about 1 mm high.

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Hsin-Chu, Taiwan

Dean E Lin