String Selection Line Stud Structure to Prevent Line Penetration
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Solution Overview
Problem
The issue of potential penetration or punching through the string selection line during the formation of the memory gate contact and/or the selection line stud in three-dimensional nonvolatile memory devices is addressed.
Innovation Solution
The semiconductor device incorporates a selection line stud made of the same material as the string selection line, with specific materials such as polysilicon used for the string selection line and tungsten for the memory gate contact, ensuring distinct materials for different components to prevent penetration issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the string selection line and memory gate contact are formed using the same material and process, then manufacturing complexity is reduced, but the string selection line may be penetrated during memory gate contact formation
Solution Approach 1:
The patent applies local quality by using different materials for different components: polysilicon for the string selection line and tungsten for the memory gate contact. This material differentiation ensures that each component has properties optimized for its specific function while preventing the string selection line from being penetrated during memory gate contact formation.
2Reliability
If the string selection line is made with a different material than the memory gate contact, then penetration is prevented, but manufacturing process complexity increases
Solution Approach 1:
The patent changes material parameters to resolve the contradiction. By selecting polysilicon for the string selection line and tungsten for the memory gate contact, the patent exploits differences in material properties (etch selectivity, mechanical strength) to prevent penetration while managing manufacturing complexity through controlled deposition processes.
Data Source
AI summary
A semiconductor device includes; a memory stack disposed on a substrate and including a lower gate electrode, an upper gate stack including a string selection line, a vertically extending memory gate contact disposed on the lower gate electrode, and a vertically extending selection line stud disposed on the string selection line. The string selection line includes a material different from that of the lower gate electrode, and the selection line stud includes a material different from that of the memory gate contact.