Semiconductor Memory Device Staircase Terrace Positioning
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Solution Overview
Problem
In stacked semiconductor memory devices, the positions of terraces formed during patterning often shift from their design positions, leading to manufacturing challenges and potential performance issues.
Innovation Solution
Incorporating a mark member made of a different material, such as silicon oxide, which is exposed at the surface and used as a reference to precisely measure the position of the end edges and terraces, allowing for accurate detection and alignment during the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the end portion of the stacked body is patterned into a staircase configuration, then contacts can be connected to electrode films, but the positions of terraces shift from design positions
Solution Approach 1:
A mark member is introduced as an intermediary reference object between the staircase configuration and the measurement system. This mark member provides a stable, identifiable reference that mediates the positioning process, allowing terrace positions to be accurately determined despite the complexity of the staircase structure.
Solution Approach 2:
The mark member creates a reference copy or surrogate for the intended design position. By measuring the position of the mark member rather than directly measuring the terrace, the system obtains an accurate representation of positional information without being affected by the measurement difficulties of the staircase configuration itself.
2Manufacturing precision
If a mark member is added for precise measurement, then terrace position accuracy improves, but device complexity increases
Solution Approach 1:
The mark member is formed in advance during the manufacturing process, specifically in the same step as the insulating film formation. This preliminary action ensures the reference is available before measurement occurs, eliminating the need for post-assembly reference addition and reducing overall process complexity.
Solution Approach 2:
The mark member serves multiple functions: it provides a reference for position measurement, acts as a structural element during manufacturing, and can be integrated with existing insulating films. This multi-functionality reduces the need for separate dedicated reference structures, thereby limiting the increase in device complexity.
3Ease of manufacture
If traditional measurement methods are used, then manufacturing process is simple, but measurement precision is insufficient
Solution Approach 1:
The patent replaces direct physical measurement of the staircase structure with an optical or imaging-based measurement of the mark member. This substitution enables higher measurement precision while keeping the manufacturing process simple, as the mark member can be measured using standard imaging techniques rather than complex mechanical measurement systems.
Data Source
AI summary
A semiconductor memory device includes a first member spreading along a first direction and a second direction, a stacked body provided on a third-direction side when viewed from the first member, and a second member provided inside the first member and exposed at a surface of the first member on the third-direction side. A configuration of an end portion in the first direction of the stacked body is a staircase configuration having terraces formed every conductive film. The second member is made from a material different from a material of the first member. The second member is totally disposed in a region opposing a total length of an end edge of the stacked body on the first-direction side, and not disposed in an outer region of the stacked body on the second-direction side.