Dual Plasma Spacer Etch for Symmetric Profiles
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Solution Overview
Problem
In semiconductor processing, self-aligned multiple patterning techniques face challenges such as residual spacer material causing micro-masking effects, oxide loss leading to uneven patterns, and asymmetric spacer top profiles due to capacitively coupled plasmas, which affect accurate pattern transfer and ion deflection in later process steps.
Innovation Solution
A method involving a spacer treatment process using a capacitively coupled plasma with H-containing chemistry followed by a spacer etch process with neutral radicals generated from a remote inductively coupled plasma, optimizing pressure and bias power to achieve symmetric and rounded spacer profiles, reducing residues and improving pattern transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a capacitively coupled plasma is used for spacer etching, then the etching process can be performed, but asymmetric spacer top profiles are generated which affect accurate pattern transfer
Solution Approach 1:
The patent changes the plasma generation mode from capacitively coupled to inductively coupled plasma, and adjusts pressure parameters (20-100 mTorr range) to achieve symmetric spacer profiles while maintaining etching effectiveness for accurate pattern transfer
Solution Approach 2:
The patent replaces the capacitively coupled plasma system with an inductively coupled plasma system, substituting the electromagnetic field generation mechanism to eliminate asymmetric profile formation while preserving the etching function
2Reliability
If conventional plasma etching is used, then spacer material can be removed, but residual spacer material causes micro-m masking effects
Solution Approach 1:
The patent optimizes pressure (20-100 mTorr) and power parameters to achieve complete spacer material removal without residues, eliminating micro-masking effects and ensuring reliable pattern transfer
Solution Approach 2:
The patent uses neutral radicals from inductively coupled plasma to create a more effective etching action that completely removes spacer material, preventing the formation of residual material that would cause micro-masking in subsequent steps
3Manufacturing precision
If oxide loss occurs during spacer processing, then spacer etching can proceed, but uneven patterns are generated affecting precision
Solution Approach 1:
The patent controls pressure (20-100 mTorr) and uses inductively coupled plasma to achieve selective spacer etching without oxide loss, maintaining pattern uniformity and precision
Solution Approach 2:
The patent converts the potential harm of oxide loss into a benefit by using neutral radicals from inductively coupled plasma that provide selective etching of spacer material while preserving the underlying oxide layer, ensuring uniform pattern 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
The method achieves good anisotropy and reduced residues in self-aligned multiple patterning, resulting in more accurate and uniform spacer profiles, which enhances pattern transfer and reduces ion deflection in subsequent process steps.
Implementation Method 1
performing a spacer treatment process to expose the workpiece to species generated from a first process gas in a first plasma
Implementation Method 2
performing a spacer etch process to expose the workpiece to neutral radicals generated from a second process gas in a second plasma
Data Source
AI summary
Systems and methods for processing a workpiece are provided. In one example, a method includes placing a workpiece on a workpiece support in a processing chamber. The method includes performing a spacer treatment process to expose the workpiece to species generated from a first process gas in a first plasma to perform a spacer treatment process on a spacer layer on the workpiece. The first plasma can be generated in the processing chamber. After performing the spacer treatment process, the method can include performing a spacer etch process to expose the workpiece to neutral radicals generated from a second process gas in a second plasma to etch at least a portion of the spacer layer on the workpiece. The second plasma can be generated in a plasma chamber that is remote from the processing chamber.