United Microelectronics Corp.

Feng-Mou Chen

Po-Wen Su

Chun-Mao Chiou

Shyan-Liang Chou

Tsung-Min Kuo

A semiconductor structure includes a substrate, a gate electrode disposed on the substrate, wherein the gate electrode has a first top surface. Agate dielectric layer is disposed between the substrate and the gate electrode. A silicon carbon nitride spacer surrounds the gate electrode, wherein the silicon carbon nitride spacer has a second top surface not higher than the first top surface. A silicon oxide spacer surrounds the silicon carbon nitride spacer.

Semiconductor structure having trimming spacers

A method of trimming spacers includes etching a silicon oxide spacer when forming an outmost spacer, so that a silicon carbon nitride spacer contacting the gate electrode exposes an area. The exposure area of the silicon carbon nitride spacer can then be partly removed by phosphate acid. At the end of the semiconductor process, at least part of the top surface of the silicon carbon nitride spacer will be lower than the top surface of a gate electrode.

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Tainan, Taiwan

Feng-Mou Chen