Fin Structure Etching With an Intermediary Layer for Loading Effects
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Solution Overview
Problem
The semiconductor industry faces challenges in maintaining uniform fin widths across different pattern densities due to etching variations during the fabrication of fin field effect transistors (finFETs), leading to loading effects that affect device performance.
Innovation Solution
The implementation of an etch-adjusting layer between the substrate and patterned patterning layers, combined with selective precursor use in plasma etching processes, to retard downward etching and enhance lateral etching, resulting in uniform fin structures across regions of varying pattern density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used without etch-adjusting layers, then the fabrication process is simpler and faster, but fin widths become non-uniform across different pattern densities due to loading effects
Solution Approach 1:
An etch-adjusting layer is introduced as an intermediary between the mandrel layer and the substrate. This layer mediates the etching process by providing a controlled interface that compensates for loading effects, enabling uniform fin width formation across both dense and isolated regions without requiring complex etching parameter adjustments
Solution Approach 2:
The etch-adjusting layer is formed in advance before the fin etching process. This preliminary action pre-compensates for the expected loading effects during etching, allowing the subsequent etching process to produce uniform fin widths without needing complex real-time adjustments
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 ensures that fin structures are formed with uniform lateral dimensions, mitigating loading effects and enhancing device performance by maintaining consistent etching profiles in both dense and isolated regions.
Implementation Method 1
performing a first etching process on the upper patterning layer to form a patterned upper patterning layer
Implementation Method 2
performing a second etching process on the lower patterning layer to form a patterned lower patterning layer
Data Source
AI summary
The present disclosure relates to a method for forming a semiconductor structure includes depositing a dielectric layer on a substrate and depositing a patterning layer on the dielectric layer. The method also includes performing a first etching process on the patterning layer to form a first region including a first plurality of blocks at a first pattern density and a second region including a second plurality of blocks at a second pattern density that is lower than the first pattern density. The method also includes performing a second etching process on the second plurality of blocks to decrease a width of each block of the second plurality of blocks and etching the dielectric layer and the substrate using the first and second pluralities of blocks to form a plurality of fin structures.