Method of forming crack free gap fill

摘要

Techniques disclosed herein may achieve crack free filling of structures. A flowable film may substantially fill gaps in a structure and extend over a base in an open area adjacent to the structure. The top surface of the flowable film in the open area may slope down and may be lower than top surfaces of the structure. A capping layer having compressive stress may be formed over the flowable film. The bottom surface of the capping layer in the open area adjacent to the structure is lower than the top surfaces of the lines and may be formed on the downward slope of the flowable film. The flowable film is cured after forming the capping layer, which increases tensile stress of the flowable film. The compressive stress of the capping layer counteracts the tensile stress of the flowable film, which may prevent a crack from forming in the base.

主权项

1. A method of forming features in a semiconductor device, the method comprising:
forming a structure having a pattern of lines and gaps over a base that extends in a horizontal direction, the lines having top surfaces, the structure is adjacent to an open area over the base, wherein the forming a structure having a pattern of lines and gaps includes forming a memory cell of a 3D memory array; forming a flowable film to substantially fill the gaps in the structure and over the base in the open area adjacent to the structure, the flowable film having a top surface in the open area that is lower than the top surfaces of the lines; forming a dielectric film over the flowable film, the dielectric film having compressive stress in the horizontal direction in the open area, the dielectric film having a bottom surface in the open area adjacent to the structure that is lower than the top surfaces of the lines; and curing the flowable film after forming the dielectric film, the curing increases tensile stress of the flowable film in the horizontal direction in the open area, the compressive stress of the dielectric film in the horizontal direction in the open area counteracts the tensile stress of the flowable film in the horizontal direction in the open area.