	US 12,237,367 B2
	Semiconductor structures and methods for forming the same
Junchao Zhang, Hefei (CN); and Cheng Yeh Hsu, Hefei (CN)
Assigned to CHANGXIN MEMORY TECHNOLOGIES, INC., Hefei (CN)
Appl. No. 17/593,034
Filed by CHANGXIN MEMORY TECHNOLOGIES, INC., Hefei (CN)
PCT Filed Apr. 12, 2021, PCT No. PCT/CN2021/086465 § 371(c)(1), (2) Date Sep. 5, 2021, PCT Pub. No. WO2021/204291, PCT Pub. Date Oct. 14, 2021.
Claims priority of application No. 202010279732.4 (CN), filed on Apr. 10, 2020.
Prior Publication US 2022/0310782 A1, Sep. 29, 2022
Int. Cl. H01L 29/06 (2006.01); H01L 21/762 (2006.01); H01L 21/8234 (2006.01)

CPC H01L 29/0649 (2013.01) [H01L 21/76224 (2013.01); H01L 21/823481 (2013.01)]

8 Claims

1. A method for forming a semiconductor structure, comprising:

providing a semiconductor substrate, a surface of the semiconductor substrate having a plurality of active areas and shallow trench isolation areas arranged in a first direction;

etching the active areas and the shallow trench isolation areas in a direction perpendicular to the first direction to form first recesses and second recesses;

covering surfaces of the first recesses and the second recesses with an adhesive layer and a metal layer;

removing the metal layer covering the surfaces of the first recesses and the second recesses by a chemical mechanical polishing process to form recesses from which the adhesive layer is exposed;

pre-etching selectively the adhesive layer exposed from second recesses in the shallow trench isolation areas in the direction perpendicular to the first direction, a depth of the pre-etching the adhesive layer being defined as H0; and

secondarily etching the metal layer and the adhesive layer in the direction perpendicular to the first direction to form contact holes, depths of the adhesive layer in the contact holes being defined as H2, the H0 being less than the H2;

wherein an upper surface of the adhesive layer in the contact holes is deeper than an upper surface of the adhesive layer in the first recesses.