Double Exposure Lithography Pattern Formation
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Solution Overview
Problem
Semiconductor manufacturing faces challenges in maintaining desired critical dimensions during lithography patterning due to pattern collapse and CD degradation, especially with high aspect ratio features and double patterning techniques, which also increase manufacturing costs and introduce issues like profile scum and round corners.
Innovation Solution
A method for lithography patterning involving the formation of multiple layers with specific materials and etching processes, including a patterned resist layer and top and middle layers, which allows for double exposure and single etch, reducing CD variation and manufacturing costs, and utilizing a top layer with enhanced etching resistance and a cross-linking polymer to maintain pattern integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If double patterning techniques are utilized to achieve smaller feature sizes, then resolution is improved, but manufacturing cost increases and additional defects are introduced
Solution Approach 1:
The patent merges the etching of middle and top layers into a single etching step by forming a combined mask structure. The resist layer and middle layer are etched simultaneously using one etching process, eliminating the need for separate etching steps that would increase manufacturing complexity and cost while maintaining the resolution benefits of double patterning.
Solution Approach 2:
The mask structure serves multiple functions: it acts as both the pattern definition layer and the etching mask for both the middle and top layers. This multi-functional approach reduces the number of separate processing steps required, thereby reducing manufacturing cost while achieving the desired high resolution through double patterning.
2Manufacturing precision
If double patterning techniques are utilized to achieve smaller feature sizes, then resolution is improved, but manufacturing complexity increases
Solution Approach 1:
The patent combines multiple etching operations into a single etching step by creating a integrated mask structure. This merging of operations simplifies the overall process flow, reducing the number of process steps from what would traditionally be required for double patterning, thereby reducing manufacturing complexity while maintaining high resolution.
3Ease of manufacture
If conventional etching is used on high aspect ratio features, then manufacturing is simpler, but pattern collapse and CD degradation occur
Solution Approach 1:
The patent performs preliminary strengthening of the mask structure by forming a cross-linked polymer layer before etching. This preliminary action reinforces the mask, enabling it to withstand the etching process without collapsing, thereby maintaining critical dimension precision while using a relatively simple etching process.
Solution Approach 2:
The mask structure is formed as a composite material system combining resist, middle layer, and cross-linked polymer. This composite structure provides both the simplicity of conventional processing and the enhanced mechanical strength needed to prevent pattern collapse during etching of high aspect ratio features, maintaining CD precision.
4Manufacturing precision
If resist layer is made thinner to achieve smaller features, then resolution is improved, but pattern collapse increases
Solution Approach 1:
The patent creates a composite mask structure where a cross-linked polymer layer is integrated with the resist and middle layer. This composite construction provides enhanced mechanical strength and stability to the overall mask structure, allowing the use of thinner resist layers for high resolution while preventing pattern collapse through the reinforcing polymer network.
Solution Approach 2:
The cross-linked polymer layer is formed in advance before the etching process, providing preliminary structural reinforcement to the mask. This preliminary strengthening action enables the thin resist layer to maintain its pattern integrity throughout the subsequent etching process, preventing collapse while achieving the desired small feature size.
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 effectively minimizes CD variation, reduces manufacturing costs, and enhances the resolution of semiconductor features by using a double patterning process with etching techniques that maintain pattern integrity and reduce defects such as profile scum and round corners.
Implementation Method 1
a top layer with enhanced etching resistance and a cross-linking polymer to maintain pattern integrity
Data Source
AI summary
Various lithography methods are disclosed. An exemplary lithography method includes forming a first patterned silicon-containing organic polymer layer over a substrate by removing a first patterned resist layer, wherein the first patterned silicon-containing organic polymer layer includes a first opening having a first dimension and a second opening having the first dimension, the first opening and the second opening exposing the substrate; forming a second patterned silicon-containing organic polymer layer over the substrate by removing a second patterned resist layer, wherein a portion of the patterned second silicon-containing organic polymer layer combines with a portion of the first patterned silicon-containing organic polymer layer to reduce the first dimension of the second opening to a second dimension; and etching the substrate exposed by the first opening having the first dimension and the second opening having the second dimension.