Selective Hardmask Capping for Precise Plasma Pattern Transfer
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Solution Overview
Problem
During semiconductor fabrication, plasma etching operations often result in rounded corners for small island or short line structures due to undesired etching of the hardmask, leading to non-ideal pattern transfer to the target layer.
Innovation Solution
A method involving the formation of a hardmask cap on the patterned hardmask during plasma etching operations, using a selective source gas that includes a halogen gas, to minimize hardmask etching and achieve more precise patterning transfer by forming a protective cap on the hardmask, thereby reducing corner rounding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma etching operations are performed on the target layer using the patterned hardmask, then the target layer is removed to transfer the pattern, but the hardmask is undesirably etched causing corner rounding
Solution Approach 1:
A protective cap is formed on the patterned hardmask before plasma etching operations. This preliminary protective layer prevents the hardmask from being etched during the plasma etching process, thereby maintaining the sharp corners and precise critical dimensions of the hardmask pattern while still allowing the target layer to be removed and patterned underneath.
2Productivity
If conventional plasma etching is used to remove the target layer, then the pattern is transferred, but corner rounding occurs on small island and short line structures
Solution Approach 1:
The protective cap acts as an intermediary layer between the plasma etching environment and the hardmask. This intermediate protective layer absorbs the harmful plasma effects that would otherwise directly attack the hardmask corners, allowing efficient pattern transfer to occur while preserving the sharp corner geometry of small island and short line structures.
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 enables nearly ideal pattern transfer with minimal corner rounding, maintaining the critical dimensions of the hardmask and ensuring precise patterning of small island and short line structures in semiconductor devices.
Implementation Method 1
performing plasma fabrication operations in parallel on the patterned hardmask and underlying target layer in a plasma etching chamber using a plasma etch gas and a selective source gas, wherein the plasma operations include forming a protective cap on the patterned hardmask
Implementation Method 2
performing plasma fabrication operations in parallel on the patterned hardmask and underlying target layer in a plasma etching chamber using a plasma etch gas
Data Source
AI summary
Disclosed is a method of manufacturing a semiconductor device. The method includes forming a patterned hardmask over an underlying target layer on a substrate; and performing plasma fabrication operations in parallel on the patterned hardmask and underlying target layer in a plasma etching chamber using a plasma etch gas and a selective source gas. The plasma operations include forming a protective cap on the patterned hardmask; and removing portions of the underlying layer that are not covered by the patterned hardmask. In various embodiments, the selective source gas includes a chemical compound that includes a halogen gas that can be dissociated into a metal and a halogen, and the plasma operations include dissociating the metal and the halogen in the selective source gas and forming a protective cap on the patterned hardmask using the metal that has been dissociated.