Cypress Semiconductor Corporation

Arya Bhattacherjee

Ritu Shrivastava

Thurman John Rodgers

William Koutny

Alp Malazgirt

Bala Padmakumar

A method of manufacturing an integrated circuit having a multilayer structure where the method includes the steps of depositing a thin layer of low temperature oxide (LTO) on top of conductors and then spinning and curing a thin layer of spin-on-glass to planarize the surface of the device. This structure is then plasma etched to remove the spin-on-glass and a portion of the LTO at approximately the same rate. The structure is then dipped in a mild potassium hydroxide solution to completely remove the SOG material, even from the crevices and gaps which are present on the surface. This enables the device to be manufactured free of any organic substances from the SOG in the body of the structure. A passivation layer can now be deposited to protect the underlying circuitry from ionic contamination, water vapor penetration and handling.

Process for improved planarization of the passivation layers for

A process for minimizing bird's beak in local oxidation of silicon which is compatible with high density (VLSI) semiconductor devices is disclosed. A pad oxide is nitridized using rapid thermal nitridization, which works quickly with minimal thermal cycling of the wafer. A silicon nitride film is then deposited over the nitridized oxide. Both films are exposed to dry plasma etching which gives more consistent results than wet methods. The field oxide is then grown and finally the masking films of the nitridized oxide and silicon nitride are removed, whereby field oxides are grown with minimal bird's beak, and minimal damage to the wafer with a small number of steps. The pad oxide may be grown in the same rapid thermal annealer used for the rapid thermal nitridization. Both cycles (pad oxide growth and nitridization of the pad oxide) can be integrated to 'one' cycle and performed sequentially in the same rapid thermal annealer to increase throughput and improve device quality.

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Fremont, CA, United States of America

Arya Bhattacherjee