Stopper Layer Layout for Misalignment-Tolerant Bit Line Contacts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices face challenges in maintaining reliability due to misalignment issues during the manufacturing process, particularly with bit line contact plugs, which can lead to short circuits with the stopper layer, affecting data storage capacity and device performance.
Innovation Solution
Incorporating a stopper layer with etch selectivity and a specific structural arrangement, including a protrusion on the word line separation structure, to prevent short circuits and enhance manufacturing precision, even in cases of misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bit line contact plugs are formed without a stopper layer, then manufacturing process is simpler, but short circuits occur between bit line contact plugs and the upper stack
Solution Approach 1:
A stopper layer is introduced as an intermediary component between the bit line contact plugs and the upper stack. This stopper layer includes a first insulating material and serves as a physical barrier that prevents direct contact between the bit line contact plugs and the upper stack, thereby eliminating short circuit risks while maintaining manufacturing feasibility.
Solution Approach 2:
The stopper layer is designed as a sacrificial or temporary structure that fulfills its protective function during operation and can be removed or is left as part of the final structure. The upper mold layer includes a second insulating material having etch selectivity with respect to the stopper layer, allowing the stopper layer to be selectively removed when needed without affecting other components.
2Manufacturing precision
If the inner side surface of the stopper layer is aligned with the inner side surface of the upper stack, then manufacturing alignment is easier, but misalignment causes short circuits
Solution Approach 1:
The stopper layer is designed with an inner side surface that is offset from the inner side surface of the upper stack, creating a preliminary protective barrier before any misalignment can occur. This offset design proactively prevents potential short circuits by ensuring that even if manufacturing misalignment occurs, the bit line contact plugs will not contact the upper stack through the offset stopper layer.
Solution Approach 2:
The stopper layer provides localized protection specifically at the interface where bit line contact plugs meet the upper stack structure. The offset design creates a localized safety zone that addresses the specific misalignment risk without requiring overall structural changes, maintaining manufacturing precision while enhancing reliability.
3Device complexity
If no offset is provided between stopper layer and upper stack, then device structure is simpler, but misalignment during manufacturing leads to short circuits
Solution Approach 1:
The offset design of the stopper layer serves as a preliminary protective measure that anticipates and prevents manufacturing misalignment issues. By creating an offset before assembly, the design builds in alignment tolerance without significantly increasing overall device complexity, as the offset is integrated into the stopper layer geometry rather than requiring separate alignment mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents short circuits and enhances the reliability of semiconductor devices by ensuring accurate alignment and contact between bit line contact plugs and the stopper layer, thereby improving data storage capacity and device performance.
Implementation Method 1
an upper mold layer on the stopper layer, the upper mold layer including a second insulating material having etch selectivity with respect to the stopper layer
Data Source
AI summary
A semiconductor device including a peripheral circuit layer on a substrate; a lower stack and upper stack on the substrate; a stopper layer on the upper stack and including an insulating material; an upper mold layer on the stopper layer; a cell channel structure extending through the layers, a side surface of the cell channel structure contacting the stopper layer; first and second capping layers; a word line separation structure including a protrusion protruding toward the stopper layer; and a bit line contact plug connected to the cell channel structure, wherein an inner side surface of the stopper layer is offset from an inner side surface of the upper stack, and in contact with the word line separation structure.