Method for determining height of insulating material in shallow trench

Abstract

The invention provides a method for determining the height of an insulating material in a shallow trench. The method comprises the following steps: providing shallow trench isolation structures with different insulating material heights; simulating mechanical pressure stress of the insulating material in the shallow trench generated to a semiconductor substrate when the insulating material is in different heights; and selecting the height of the corresponding insulating material in the shallow trench as an optimal value when the mechanical pressure stress is minimum. The method selects the optimal height of the insulating material to ensure the optimal depression degree on the edge of the shallow trench and minimum generated leakage current.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for determining the height of an insulating material in a shallow trench. Background technique [0002] As the size of integrated circuits decreases, the devices that make up the circuits must be placed more densely to fit the limited space available on the chip. Since current research is devoted to increasing the density of active devices per unit area of ​​a semiconductor substrate, effective insulating isolation between circuits becomes more important. [0003] Shallow trench isolation (STI) technology has many process and electrical isolation advantages, including reducing the area occupied by the wafer surface while increasing the integration of devices, maintaining surface flatness and reducing channel width erosion. However, while the device size continues to shrink, the need to control the mechanical stress between devices is a key point to ensure high pe...

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Problems solved by technology

[0009] In the process of forming the shallow trench isolation structure in the prior art, after the insulating material in the shallow trench is planarized by chemical mechanical polishing, it is not possible to determine the appropriate height of the insulating material. When the height is too low, it will cause the edge of the shallow trench If the depression is too large, it will easily lead to leakage current; if the height is too high, the mechanical compressive stress generated by the insulating material and lining oxide layer in the shallow trench will increase on the semiconductor substrate, and leakage current will also occur; Electrical performance of increasingly smaller semiconductor devices is adversely affected

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