Resist Pitch Splitting for High Density Patterning
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Solution Overview
Problem
Current semiconductor manufacturing techniques, such as quadruple patterning and self-aligned quadruple patterning, face challenges in achieving high pattern density and structural integrity due to spatial limitations, cost, and complexity, particularly in maintaining aspect ratios and throughput without using extreme ultraviolet lithography.
Innovation Solution
A method that performs pitch splitting at the resist level without hard mandrels, using a substrate with a patterned resist layer and underlying layers like silicon anti-reflective coating and silicon oxynitride, followed by conformal spacer deposition and reactive ion etch processes to create and transfer spacer patterns, achieving high pattern density and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional quadruple patterning or self-aligned quadruple patterning is used to achieve smaller critical dimensions, then the critical dimension can be reduced below photolithographic capabilities, but the process complexity increases with multiple deposition and etch steps, and the number of tools required increases
Solution Approach 1:
The patent extracts and eliminates the hard mandrel layer from the conventional SAQP process. By performing pitch splitting directly at the resist level without requiring hard mandrels for spacer formation, the process removes unnecessary deposition and etch steps, reducing overall process complexity while maintaining the ability to achieve sub-photolithographic critical dimensions
Solution Approach 2:
The patent inverts the conventional approach by transferring the high-density pattern at the very end of the integration scheme rather than at the beginning. This reversal allows pitch splitting to occur at the resist level first, followed by spacer formation and final pattern transfer, simplifying the process flow and reducing the number of required tools
2Manufacturing precision
If self-aligned quadruple patterning is used to achieve high pattern density, then the critical dimension can be reduced, but the structural integrity of the structures may not hold up in further processing
Solution Approach 1:
The patent applies preliminary resist hardening processing before spacer deposition to maintain square top pattern retention. This preliminary action strengthens the resist structures early in the process, ensuring they have sufficient structural integrity to withstand subsequent processing steps while enabling high pattern density through pitch splitting at the resist level
3Manufacturing precision
If additional layers are deposited and selectively etched in SAQP to achieve required critical dimensions, then the critical dimension can be reduced, but the cost and processing time increase
Solution Approach 1:
The patent merges the pitch splitting function with the resist patterning step by performing pitch splitting directly at the resist level. This consolidation eliminates the need for separate hard mandrel deposition and etch steps, reducing both processing time and cost while maintaining the ability to achieve the required critical dimensions through subsequent spacer formation
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 allows for increased pattern density and structural integrity, reducing the number of tools and steps, minimizing cost and setup time, and improving patterning uniformity, pulldown, slimming, and line width roughness, while avoiding the use of hard mandrels.
Implementation Method 1
performing a first conformal spacer deposition using an atomic layer deposition technique with an oxide, the deposition creating a first conformal layer above the patterned resist layer
Implementation Method 2
performing a spacer first reactive ion etch (RIE) process and a first pull process on the first conformal layer, the first RIE process and a first pull process creating a first spacer pattern
Data Source
AI summary
Provided is a method for increasing pattern density of a structure using an integration scheme and perform pitch splitting at the resist level without the use of hard mandrels, the method comprising: providing a substrate having a patterned resist layer and an underlying layer comprising a silicon anti-reflective coating layer, an amorphous layer, and a target layer; performing a resist hardening process; performing a first conformal spacer deposition using an atomic layer deposition technique with an oxide, performing a spacer first reactive ion etch process and a first pull process on the first conformal layer, performing a second conformal spacer deposition using titanium oxide; performing a second spacer RIE process and a second pull process, generating a second spacer pattern; and transferring the second spacer pattern into the target layer, wherein targets include patterning uniformity, pulldown of structures, slimming of structures, aspect ratio of structures, and line width roughness.