Staircase etch control in forming three-dimensional memory device

US10522474B2 · kind B2 · utility

Assignee

• YANGTZE MEMORY TECHNOLOGIES CO., LTD. · CN

Inventors

• Zhenyu Lu · Hubei, CN
• Lidong Song · Hubei, CN
• Yongna Li · Hubei, CN
• Feng Pan · Kunshan, CN
• Xiaowang Dai · Hubei, CN
• Dan Liu · Beijing, CN
• Steve Weiyi Yang · Hubei, CN
• Simon Shi-Ning Yang · Portland, US

Key dates

• Filing date: Jul 26, 2018
• Grant date: Dec 31, 2019
• Expiry date: Jul 26, 2038

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10B43/50
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

Embodiments of three-dimensional (3D) memory devices and methods for controlling a photoresist (PR) trimming rate in the formation of the 3D memory devices are disclosed. In an example, 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.