Semiconductor Device Sidewall Image Transfer for Dense Patterning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional single patterning processes face limitations in creating smaller, more densely packed features in semiconductor devices due to overlay accuracy and resolution challenges, necessitating the development of improved methods for forming tiny elements in semiconductor substrates.
Innovation Solution
A multiple patterning process utilizing sidewall image transfer (SIT) and double patterning techniques to form intertwined patterns with a reduced number of photomasks, allowing for the creation of finer structures with a compact layout through crossed photomask patterns and corresponding pattern formation in the target layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If single patterning process is used, then the process is simple and cost-effective, but the feature size and density are limited by overlay accuracy and resolution
Solution Approach 1:
The patterning process is divided into multiple sequential steps: first forming initial patterns, then forming sidewalls on these patterns, and finally transferring the sidewall patterns to create the final dense structure. This segmentation allows each step to work within achievable precision limits while the combination achieves higher overall density
Solution Approach 2:
The method performs preliminary pattern formation using conventional lithography to create mandrels, then uses these mandrels as templates to guide subsequent sidewall formation and pattern transfer. This preliminary action enables the final high-density pattern to be achieved through controlled material deposition and removal rather than direct patterning
2Area of moving object
If feature sizes are decreased to increase device density, then more devices can be packed, but overlay accuracy and resolution become insufficient
Solution Approach 1:
Sidewalls are introduced as an intermediary structure that bridges the gap between the lithographically-defined mandrels and the final target pattern. The sidewalls, formed by conformal deposition, provide precise dimensional control through thickness control rather than relying on lithographic resolution, enabling sub-lithographic feature sizes
Solution Approach 2:
The method replaces direct optical patterning (which is limited by diffraction and overlay accuracy) with a mechanical/depositional approach where sidewalls are formed by conformal film deposition. This substitution uses deposition thickness control, which has superior precision compared to lithographic overlay control at small dimensions
3Manufacturing precision
If multiple patterning processes are used to achieve smaller features, then feature density improves, but the number of photomasks and process steps increases
Solution Approach 1:
The method merges the pattern definition function and the pattern transfer function into a single integrated process flow. The sidewall formation step simultaneously creates the pattern definition and serves as the template for subsequent etching, eliminating the need for separate photomask steps that would otherwise be required
Data Source
AI summary
A semiconductor device and a method of forming the same, the semiconductor device includes a substrate and a material layer. The substrate has a first region, and the material layer is disposed on the substrate. The material layer includes plural of first patterns and plural of second patterns arranged in an array, and two third patterns. The first patterns are disposed within the first region, the second patterns are disposed at two opposite outer sides of the first region, and the third patterns are disposed at another two opposite outer sides of the first region, wherein each of the third patterns partially merges each of a part of the first patterns and each of a part of the second patterns.