Taiwan Semiconductor Manufacturing Comp. Ltd.

Ching Lang Yen

Ling-Sung Wang

Kuo Hui Chang

Chao-Tzung Tsai

Shing Lee

Methods are provided for making retrograde trench isolation structures with improved electrical insulation properties. One method comprises the steps of: forming a retrograde trench in a silicon substrate, and forming a layer of silicon oxide on the walls of the trench by thermal oxidation, such that the trench is sealed and a space is formed within the layer of silicon oxide. The space can contain a vacuum or any of a variety of gases depending upon conditions of the thermal oxidation step. Retrograde trench isolation structures containing a space are also provided.

Retrograde trench isolation structures

A method of improving the yield and performance of IC devices fabricated on a semiconductor wafer is disclosed. The method includes fabricating via plugs in via openings provided in an intermetal dielectric (IMD) layer on a wafer, subjecting the wafer to CMP to isolate the via plugs, immersing and soaking the wafer in deionized (DI) water, and drying the wafer using isopropyl alcohol, typically in a Marangoni-type dryer. The Marangoni IPA drying step prevents the formation of static electricity on the wafer, and thus, prevents the adherence of small charged particles to the wafer. As a result, the yield of IC devices fabricated on the wafer, as well as the performance of the devices, is enhanced.

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Hsinchu, Taiwan

Ching Lang Yen