Ring Pattern Layer for 3D Memory Alignment and Etch Control
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Solution Overview
Problem
The challenge in increasing the data capacity of three-dimensional semiconductor devices lies in forming a single vertical hole that completely passes through a vertically long stack with an increased number of stacked layers, which is difficult due to alignment issues and process defects when using a combination of upper and lower vertical holes.
Innovation Solution
A semiconductor device with a ring pattern layer disposed between two stacks, where the ring pattern layer comprises a plurality of ring patterns surrounding each pillar-structure, facilitating the formation of pillar-structures by aligning upper and lower holes effectively and preventing fin-type groove formation during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single vertical hole is formed to completely pass through a vertically long stack with increased number of stacked layers, then the data capacity of the semiconductor device is improved, but the manufacturing precision deteriorates due to alignment issues and process defects
Solution Approach 1:
The patent divides the single vertical hole formation process into multiple segments: first holes are formed in the lower stack, then second holes are formed in the upper stack. The ring pattern acts as an intermediary structure that connects these segments. This segmentation allows each hole formation process to be optimized independently while maintaining overall alignment, thus resolving the contradiction between achieving complete vertical penetration and maintaining manufacturing precision.
Solution Approach 2:
The ring pattern serves as an intermediary structure between the first and second stacks. It provides a reference structure that facilitates precise alignment of the first and second holes. The ring pattern is formed after the first holes and before the second holes, acting as a mediator that enables accurate positioning of the upper holes relative to the lower holes, thereby maintaining manufacturing precision while enabling complete vertical hole formation.
2Ease of manufacture
If a combination of upper and lower vertical holes is used to pass through a vertically long stack, then the formation of complete vertical holes is achieved, but process defects increase due to alignment problems
Solution Approach 1:
The ring pattern is formed as a preliminary action before forming the second holes. This preliminary structure provides a physical reference that guides the formation of the second holes, ensuring they align with the first holes. By preparing this intermediary structure in advance, the patent eliminates alignment problems that would otherwise cause process defects, thus improving reliability while maintaining ease of manufacture.
3Productivity
If the vertically long stack is completely passed through by a combination of upper and lower vertical holes, then the integration density is improved, but fin-type groove formation occurs during etching
Solution Approach 1:
The ring pattern acts as an intermediary etch-stop layer during the etching process. When etching the second holes, the ring pattern prevents the etchant from penetrating too deeply into the lower stack, thereby preventing fin-type groove formation. This intermediary structure allows complete vertical hole formation for high integration density while simultaneously preventing the harmful fin-type groove defect.
Data Source
AI summary
A semiconductor device includes a first stack including a plurality of alternating layers of first interlayer insulating layers and first conductive patterns; a second stack including a plurality of alternating layers of second conductive patterns and second interlayer insulating layers, the second stack being positioned above the first stack; a plurality of pillar-structures each pillar structure passing through the first and second stacks; and a ring pattern layer disposed between the first and second stacks, the ring pattern layer comprising a plurality of ring patterns, each ring pattern surrounding each pillar-structure.