Hard Mask Line-End Extensions for Reduced Feature Gaps
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Solution Overview
Problem
As semiconductor integrated circuit (IC) feature sizes decrease, the spacing between adjacent features is constrained by the limits of photolithographic and cutting processes, making it difficult to achieve minimal gaps between patterned features without additional mask processes.
Innovation Solution
The method involves forming line-end extensions in a hard mask layer using directed ion beams, where the patterned photoresist blocks some ions from reaching these extensions, altering their physical properties to facilitate selective etching and allowing for self-aligned patterning of features with reduced gaps between them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithographic masks and cut processes are used to reduce feature size and spacing, then manufacturing precision is improved, but device complexity increases due to the need for multiple masks and processes
Solution Approach 1:
Line-end extensions are formed in the hard mask layer before the main patterning process. This preliminary formation of extensions at the ends of mask lines allows subsequent etching to automatically create features with reduced spacing without requiring additional mask processes, thus resolving the contradiction between precision and complexity
Solution Approach 2:
The line-end extensions self-align with the photoresist pattern during etching. The extensions automatically position themselves at the correct locations based on the photoresist geometry, eliminating the need for separate alignment and positioning steps that would increase process complexity while maintaining manufacturing precision
2Manufacturing precision
If additional cut layers or mask processes are used to reduce gaps between features, then manufacturing precision is improved, but productivity decreases due to increased process steps
Solution Approach 1:
The formation of line-end extensions and the main feature patterning are merged into a single etching process. The line-end extensions and the main mask pattern are etched simultaneously in one step, eliminating the need for separate cut layers or additional mask processes, thus improving productivity while achieving gap reduction
Solution Approach 2:
The line-end extensions serve multiple functions: they define the precise location for feature formation, self-align during etching, and enable gap reduction all within a single process step. This multi-functionality eliminates the need for dedicated additional processes, thereby maintaining productivity while improving manufacturing precision
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
This approach enables a significant reduction in the gap between patterned features, increasing feature density without the need for additional cut layers or mask processes, thereby enhancing manufacturing efficiency and reducing costs.
Implementation Method 1
the patterned photoresist blocks some ions from reaching these extensions, altering their physical properties to facilitate selective etching
Data Source
AI summary
Methods of forming line-end extensions and devices having line-end extensions are provided. In some embodiments, a method includes forming a patterned photoresist on a first region of a hard mask layer. A line-end extension region is formed in the hard mask layer. The line-end extension region extends laterally outward from an end of the first region of the hard mask layer. The line-end extension region may be formed by changing a physical property of the hard mask layer at the line-end extension region.