Etch Stop Layer Pattern for Semiconductor Alignment
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Solution Overview
Problem
Highly integrated semiconductor devices face challenges in aligning features such as bit lines and semiconductor patterns, leading to potential operational failures and reduced manufacturing process margins due to misalignment during the formation of contact plugs and bit lines.
Innovation Solution
The method involves alternately forming insulating interlayers and sacrificial layers on a substrate, creating etch stop layers and grooves to form gate structures, and using spacer-shaped etch stop layers to prevent damage to insulating interlayers during the formation of bit line contacts and contact plugs, ensuring accurate alignment and preventing operational failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a high degree of integration is achieved by stacking memory cells vertically, then device density and capacity are improved, but alignment precision between features (bit line and semiconductor pattern) deteriorates
Solution Approach 1:
An etch stop layer pattern is introduced as an intermediary element between the insulating interlayer and the underlying structures. This patterned layer serves as a reference marker that facilitates precise alignment during subsequent etching processes for forming contact holes, thereby resolving the alignment precision issue while maintaining high device density
Solution Approach 2:
The etch stop layer pattern is formed in advance before the critical alignment steps. By pre-establishing this reference pattern, the methodology enables subsequent processes to align accurately to it, preventing misalignment issues before they occur during contact hole formation
2Manufacturing precision
If misalignment occurs during formation of contact plugs and bit lines, then manufacturing process margin is reduced, but device reliability deteriorates
Solution Approach 1:
The etch stop layer pattern acts as a mediator that decouples the alignment requirements from the final contact hole positioning. Even if slight misalignment occurs, the patterned etch stop layer provides a stable reference that prevents complete misalignment, thereby maintaining both process margin and device reliability
Solution Approach 2:
The etch stop layer pattern provides a cushioning effect against alignment errors. By having this intermediate reference layer in place, the process can absorb certain degrees of misalignment without causing catastrophic failures, thus cushioning the impact on device reliability
Data Source
AI summary
A semiconductor device includes a semiconductor pattern on a substrate, gate structures on sidewalls of the semiconductor pattern, the gate structures being spaced apart from one another, insulating interlayers among the gate structures, wherein an uppermost insulating interlayer is lower than an upper face of the semiconductor pattern, a common source line contacting the substrate and protruding above the uppermost insulating interlayer, an etch stop layer pattern on the semiconductor pattern and on the common source line wherein the common source line protrudes above the uppermost insulating interlayer, an additional insulating interlayer on the uppermost insulating interlayer, and contact plugs extending through the additional insulating interlayer so as to make contact with the semiconductor pattern and the common source line, respectively.