US 12,302,555 B2
Method for forming bit line contact structure and semiconductor structure
Xiayu Shi, Hefei (CN)
Assigned to CHANGXIN MEMORY TECHNOLOGIES, INC., Hefei (CN)
Filed by CHANGXIN MEMORY TECHNOLOGIES, INC., Hefei (CN)
Filed on Feb. 21, 2022, as Appl. No. 17/676,283.
Application 17/676,283 is a continuation of application No. PCT/CN2021/108202, filed on Jul. 23, 2021.
Claims priority of application No. 202110005940.X (CN), filed on Jan. 5, 2021.
Prior Publication US 2022/0216217 A1, Jul. 7, 2022
Int. Cl. H10B 12/00 (2023.01)
CPC H10B 12/485 (2023.02) [H10B 12/315 (2023.02); H10B 12/34 (2023.02)] 13 Claims
OG exemplary drawing
 
1. A method for forming a bit line contact structure, comprising:
successively disposing a first mask layer, a second mask layer, and a photoresist on a surface of a substrate, on which a plurality of word lines and a protection layer are provided, and patterning the photoresist to obtain a patterned photoresist;
successively etching the second mask layer and the first mask layer by utilizing the patterned photoresist, so as to form a first opening penetrating the first mask layer and the second mask layer;
disposing a sacrificial layer on a surface of the second mask layer, wherein the sacrificial layer covers sidewalls and a bottom wall of the first opening, so as to form a second opening having an opening width smaller than that of the first opening;
etching a surface of the protection layer to form a third opening corresponding to the second opening by utilizing the second opening, and meanwhile removing the sacrificial layer to expose the first opening; and
etching through the protection layer by utilizing the first opening and the third opening to form a bit line contact hole at the surface of the substrate, wherein the bit line contact hole is configured to form a bit line contact structure, and the bit line contact hole comprises a first hole portion and a second hole portion, the first hole portion opens at the surface of the protection layer, a hole diameter of the second hole portion is smaller than that of the first hole portion, and the second hole portion opens at a bottom wall of the first hole portion.