Silicon Layer Feature Etching with Bias-Controlled Plasma
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Solution Overview
Problem
Conventional semiconductor fabrication processes for forming high aspect ratio features in silicon containing layers lack sufficient control over feature dimensions, resulting in non-uniform profiles and microloading issues.
Innovation Solution
A method involving exposure to a first plasma formed from chlorine or bromine containing gases with bias power, followed by exposure to a second plasma formed from oxygen or nitrogen containing gases without bias power, to etch and oxidize/nitride the features, ensuring uniformity and improved control over feature profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polymer forming gas (e.g., CF4) with pulsed bias power is used, then the etching process can be performed, but sufficient control over feature dimensions is not achieved resulting in non-uniform feature profiles
Solution Approach 1:
The etching process is segmented into two distinct plasma exposure steps: first a chlorine-containing plasma with bias power for controlled etching, then an oxygen-containing plasma without bias power for oxidation. This segmentation allows independent optimization of each step's parameters to achieve both dimension control and profile uniformity
Solution Approach 2:
The invention changes multiple parameters simultaneously: switches from fluorine-based to chlorine-based process gas, implements alternating bias power application, and transitions between different gas chemistries (chlorine-containing then oxygen-containing). These parameter changes collectively improve feature dimension control and profile uniformity
2Length of moving object
If high aspect ratio features are formed using conventional processes, then the features can be created, but microloading issues and non-uniform profiles occur due to insufficient dimension control
Solution Approach 1:
The oxidation step using oxygen-containing plasma without bias power is performed as a preliminary action to protect the etched feature walls before subsequent processing. This preliminary oxidation prevents microloading effects and ensures uniform profiles in high aspect ratio features by stabilizing the feature geometry early in the process sequence
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 method enhances control over feature profiles and dimensions, particularly for high aspect ratio features, reducing lateral etching and microloading, and is suitable for sub-20 nm device node applications.
Implementation Method 1
exposing the substrate to a first plasma formed from a first process gas while providing a bias power to the substrate support, wherein the first process gas comprises one or more of a chlorine-containing gas or a bromine containing gas
Implementation Method 2
exposing the substrate to a second plasma formed from a second process gas while no bias power is provided to the substrate support, wherein the second process gas comprises one or more of an oxygen-containing gas or nitrogen gas
Data Source
AI summary
Embodiments of methods for forming features in a silicon containing layer of a substrate disposed on a substrate support are provided herein. In some embodiments, a method for forming features in a silicon containing layer of a substrate disposed on a substrate support in a processing volume of a process chamber includes: exposing the substrate to a first plasma formed from a first process gas while providing a bias power to the substrate support, wherein the first process gas comprises one or more of a chlorine-containing gas or a bromine containing gas; and exposing the substrate to a second plasma formed from a second process gas while no bias power is provided to the substrate support, wherein the second process gas comprises one or more of an oxygen-containing gas or nitrogen gas, and wherein a source power provided to form the first plasma and the second plasma is continuously provided.