United Microelectronics Corp.

Jin-sheng Yang

Tzung-Han Lee

Kun-Chi Lin

Pei-Lin Kuo

Huo-Tieh Lu

A method of forming a strain-causing layer for MOS transistors is provided, which is applied to a substrate having a plurality of gate structures of the MOS transistors thereon. A non-conformal stressed film that is thicker on the gate structures than between the gate structures is formed over the substrate. The non-conformal stressed film is then etched, without an etching mask thereon, to remove portions thereof between the gate structures and disconnect the stressed film between the gate structures. At least one extra stressed film may be further formed over the substrate, wherein each extra stressed film has the same type of stress as the above stressed film and is connected or disconnected between the gate structures.

Method of forming strain-causing layer for MOS transistors and process for fabricating strained MOS transistors

A fabrication method for an ultra-small opening is described, wherein a first photoresist layer is formed on a substrate. Exposure and development processes are further conducted to transfer the desired pattern with a small opening from the mask layer onto the surface of the first photoresist layer. A plasma treatment is then conducted on the first photoresist layer, followed by coating a second photoresist layer on the first photoresist layer.

Method for fabricating an ultra small opening

A method of defining a mask pattern for a photoresist layer in semiconductor fabrication. The method coats a photoresist layer containing an additive on a dielectric layer. The photoresist layer has an opening formed therein. The additive is 2,2&prime;-azo-bis-isobutyronitride (AIBN) or phenyl-azo-triphenylmethane. The photoresist layer is exposed and developed. Then, a hard baking step is performed. A UV curing or a hot curing step is performed on the photoresist layer. As a result, the additive in the photoresist layer reacts to form nitrogen (N ) gas. Nitrogen gas makes the photoresist layer expand. The opening is decreased by the expansion of the photoresist layer. The dielectric layer is etched according to the expanded photoresist layer so that a via or a trench, which is smaller than a conventional one, is formed.

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Hsinchu, Taiwan

Jin-sheng Yang