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|1. (WO2018161865) STAIRCASE ETCH CONTROL IN FORMING THREE-DIMENSIONAL MEMORY DEVICE|
|Applicants:||YANGTZE MEMORY TECHNOLOGIES CO., LTD.
YANG, Steve, Weiyi
YANG, Simon, Shi-Ning
|Title:||STAIRCASE ETCH CONTROL IN FORMING THREE-DIMENSIONAL MEMORY DEVICE|
Three-dimensional (3D) memory devices and methods for controlling a photoresist (PR) trimming rate in the formation of the 3D memory devices are disclosed. A method includes forming a dielectric stack over a substrate, measuring a first distance between the first trimming mark and the PR layer along a first direction, and trimming the PR layer along the first direction. The method also includes etching the dielectric stack using the trimmed PR layer as an etch mask to form a staircase, forming a second trimming mark using the first trimming mark as an etch mask, measuring a second distance between the second trimming mark and the trimmed PR layer, comparing the first distance with the second distance to determine a difference between an actual PR trimming rate and an estimated PR trimming rate, and adjusting PR trimming parameters based on the difference.