Method of forming integrated circuit structure

Abstract

A method of forming an integrated circuit structure includes providing a semiconductor substrate; forming a first isolation region in the semiconductor substrate; after the step of forming the first isolation region, forming a metal-oxide-semiconductor (MOS) device at a surface of the semiconductor substrate, wherein the step of forming the MOS device comprises forming a source / drain region; and after the step of forming the MOS device, forming a second isolation region in the semiconductor substrate.

Description

technical field [0001] The present invention relates to integrated circuits, and more particularly to the formation of isolation structures used to separate integrated circuits. Background technique [0002] Integrated circuits are formed on the surface of semiconductor substrates, primarily silicon substrates. The semiconductor elements are isolated from each other by an isolation structure close to the surface of the substrate. The isolation structure includes field oxides and shallow trench isolation (STI). [0003] Field oxide regions are often formed using local oxidation of silicon (LOCOS). A typical process includes blanket forming a mask layer on the substrate, and then patterning the mask layer to expose a portion of the underlying silicon substrate. Next, thermal oxidation is performed in an oxygen-containing atmosphere to oxidize the exposed portion of the silicon substrate. Next, the mask layer is removed. [0004] As the size of integrated circuits shrinks,...

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Problems solved by technology

This makes the shallow trench insulated 8 2 more prone to holes

This causes STI 8 2 The stress induced in the gate length direction changes unfavorably

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