Semiconductor Pattern Formation via Sacrificial Boundary Layer
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Solution Overview
Problem
The double patterning technique in semiconductor manufacturing is complex and costly, with challenges in accurately aligning exposure processes and forming microscopic patterns, leading to increased manufacturing costs and potential misalignment issues.
Innovation Solution
A pattern forming method that eliminates the second exposure process by using a first photoresist pattern, a selectively removable boundary layer, and a second mask material layer to form a void between the patterns, followed by a trimming process to achieve the desired pattern widths, simplifying the process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If double patterning is performed with two exposure processes, then finer pattern gaps can be formed, but the process becomes complicated and manufacturing cost increases
Solution Approach 1:
The patent segments the patterning process into distinct stages: first forming a mandrel pattern, then creating a sacrificial layer, followed by forming a second pattern layer. This segmentation allows each stage to be optimized independently, achieving fine pattern gaps without requiring complex double exposure alignment processes.
Solution Approach 2:
The patent introduces a sacrificial layer as an intermediary element between the mandrel pattern and the final pattern. This sacrificial layer enables the formation of fine gaps through selective removal, avoiding the need for precise double exposure alignment while achieving the desired pattern fineness.
2Manufacturing precision
If double patterning is performed with two exposure processes, then finer pattern gaps can be formed, but manufacturing cost increases
Solution Approach 1:
By segmenting the patterning into sequential steps using different materials (mandrel, sacrificial layer, second pattern layer), the process avoids costly double exposure alignment while achieving fine pattern gaps through standard lithography and selective etching processes.
Solution Approach 2:
The sacrificial layer acts as a temporary, disposable element that enables fine pattern formation but is subsequently removed. This approach uses inexpensive temporary materials to achieve precision that would otherwise require expensive double exposure processes.
3Manufacturing precision
If double patterning is performed, then finer pattern gaps can be formed, but alignment accuracy becomes difficult to maintain
Solution Approach 1:
The sacrificial layer serves as a physical intermediary that defines the gap position and size through its thickness and pattern geometry, eliminating the need for alignment between two exposure processes. The final pattern alignment is determined by the sacrificial layer dimensions rather than by aligning two separate exposures.
Solution Approach 2:
The mandrel pattern and sacrificial layer are formed in advance with precise dimensions before the final pattern is created. This preliminary structuring establishes the gap geometry independently of subsequent alignment operations, ensuring consistent pattern fineness without alignment errors.
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 method allows for accurate formation of microscopic patterns without a second exposure process, simplifying the manufacturing process and reducing semiconductor device production costs while maintaining pattern precision.
Implementation Method 1
a first pattern forming process for forming a first pattern by patterning a first mask material layer made of a photoresist
Implementation Method 2
a boundary layer etching process for forming a second pattern made of the second mask material layer by etching and removing the boundary layer and forming a void between the sidewall portions of the first pattern and the second mask material layer
Data Source
AI summary
Provided is a pattern forming method for forming a pattern serving as a mask, which includes: a process for forming a first pattern 105 made of a photoresist; a process for forming a boundary layer 106 at sidewall portions and top portions of the first pattern 105; a process for forming a second mask material layer 107 to cover a surface of the boundary layer 106; a process for removing a part of the second mask material layer 107 to expose top portions of the boundary layer 106; a process for forming a second pattern made of the second mask material layer 107 by etching and removing the boundary layer 106; and a trimming process for reducing a width of the first pattern 105 and a width of the second pattern to predetermined widths.