Non-periodic Circuit Pattern Formation Using Etching Selectivity
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Solution Overview
Problem
Conventional pattern forming methods, such as the Pitch-Splitting Process and Spacer Double Patterning Process, struggle to create non-periodic circuit patterns with features smaller than the resolution limit of exposure apparatuses, lacking precision in forming such patterns.
Innovation Solution
The method involves forming multiple layers of line patterns with different etching characteristics, selectively removing portions, and using mask layers to achieve high precision in creating non-periodic patterns by utilizing the differences in etching characteristics between these patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional pattern forming methods (Pitch-Splitting Process or Spacer Double Patterning Process) are used, then periodic circuit patterns with pitch below resolution limit can be formed, but non-periodic portions cannot be formed with high precision
Solution Approach 1:
The pattern formation process is divided into multiple sequential steps: first forming line patterns at a relaxed pitch, then selectively removing portions, and finally forming spacer patterns. This segmentation allows different regions (periodic and non-periodic) to be formed using different mechanisms, achieving high precision for non-periodic portions that cannot be directly formed by single exposure
Solution Approach 2:
Line patterns are formed in advance at a pitch that is within the resolution capability of the exposure apparatus. These preliminary line patterns serve as templates for subsequent selective removal and spacer formation, enabling the final non-periodic pattern to achieve precision beyond the exposure apparatus resolution limit
2Manufacturing precision
If exposure apparatus resolution limit is used as the basis for pattern formation, then direct patterning is simple, but features smaller than resolution limit cannot be formed
Solution Approach 1:
Spacer materials are deposited as an intermediary layer between the exposure apparatus capability and the final desired pattern. The spacers are formed by conformal deposition on the line patterns and then anisotropically etched, allowing the final pattern dimensions to be determined by the spacer thickness rather than the exposure resolution, thus achieving features smaller than the resolution limit
Solution Approach 2:
The pattern formation transitions from a two-dimensional exposure process to a three-dimensional spacer deposition and etching process. By utilizing the vertical dimension for spacer deposition and then performing directional etching, the method achieves horizontal pattern dimensions that are controlled by vertical spacer thickness, effectively bypassing the exposure apparatus resolution limit
Data Source
AI summary
A device manufacturing method includes forming, in a first layer, first line patterns of which longitudinal direction is a first direction; and forming, in a second layer above the first layer, second line patterns of which longitudinal direction is a second direction crossing the first direction, and third line patterns of which longitudinal direction is the second direction and having a etching characteristic different from an etching characteristic of the second line patterns. At least one edge portion of each of the second line patterns and at least one edge portion of each of the third line patterns are adjacent. As viewed from above the second layer, the adjacent at least one edge portions of one of the second and third line patterns are positioned between two adjacent line patterns of the first line pattern.