Semiconductor Storage Device Dummy Insulation Plug Etch Stop
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Solution Overview
Problem
Existing semiconductor storage devices with three-dimensionally arranged memory cells face challenges in maintaining operational reliability due to issues with contact plug formation and the potential for overetching, which can lead to defects and reduced reliability.
Innovation Solution
The semiconductor storage device incorporates a dummy insulation plug as an etch stop during the formation of contact plugs, preventing overetching and ensuring accurate connection to the intended word line, while also forming support columns to prevent structural collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact plugs are formed without a dummy insulation plug as etch stop, then manufacturing process is simpler, but overetching occurs causing defects and reduced reliability
Solution Approach 1:
A dummy insulation plug is introduced as an intermediary element between the contact plug and the word line. This dummy plug serves as an etch stop during contact plug formation, preventing the etching process from penetrating through the word line and causing overetching defects. The dummy plug is filled with insulating material to maintain electrical isolation while providing mechanical support during manufacturing.
2Productivity
If word lines are made thinner to increase stacking, then more word lines can be stacked, but contact plug formation becomes difficult and overetching risk increases
Solution Approach 1:
The dummy insulation plug is formed in advance before contact plug formation, creating a pre-established etch stop structure. This preliminary action ensures that when contact plugs are subsequently formed, the etching process automatically stops at the dummy plug interface, preventing penetration through the thin word line structures and ensuring precise contact plug positioning even in high-density stacked configurations.
3Reliability
If no support columns are formed, then manufacturing process is simpler, but structural collapse occurs reducing reliability
Solution Approach 1:
The support structure is segmented into multiple support columns distributed across the substrate, with each column positioned at critical locations to prevent local structural collapse. These support columns are formed from the same insulating material as the dummy plugs and are integrated into the existing manufacturing process, providing distributed structural reinforcement without requiring a separate complex support system.
Data Source
AI summary
A semiconductor storage device includes a substrate having a surface, a first conductive layer 25 disposed on a substrate and extending in an X direction parallel to the surface of the substrate; a second conductive layer 25 that disposed on the first conductive layer 25 and extending in the X direction; an insulation plug 30 disposed on the substrate, extends in a Z direction intersecting with the X direction, and intersects with the first conductive layer 25; and a contact plug CC disposed on the first insulation plug 30, extends in the Z direction, and intersects with the second conductive layer 25.