Plasma Etching Recess Width Control via Substrate Cooling
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Solution Overview
Problem
Existing etching methods for silicon-containing films struggle to precisely control the width of recesses formed during plasma etching, leading to inconsistent results due to limitations in adjusting the adhesion of by-products containing silicon and nitrogen on the side walls.
Innovation Solution
The method involves adjusting the temperature of the substrate support to −20° C. or lower and controlling the flow rate of nitrogen-containing gases to manage the adhesion of by-products on the side walls, allowing for precise control of the recess width by optimizing etching parameters such as temperature and gas flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma etching is used for silicon-containing films, then etching can be performed, but the width of the recess cannot be precisely controlled due to inconsistent adhesion of by-products on side walls
Solution Approach 1:
The invention changes the substrate temperature parameter to -20°C or lower, which fundamentally alters the adhesion behavior of silicon-nitrogen by-products on the side walls. This temperature parameter change enables precise control of the recess width by regulating the degree of by-product adhesion, thereby resolving the inconsistency in etching process results.
2Manufacturing precision
If substrate temperature is lowered to -20°C or lower, then by-product adhesion on side walls is enhanced, but process complexity increases due to temperature control requirements
Solution Approach 1:
By establishing a specific temperature threshold of -20°C or lower, the invention creates a clear parameter boundary that achieves the desired by-product adhesion effect. This quantified parameter change simplifies the control strategy compared to attempting to fine-tune adhesion through multiple variables, making the temperature control system more manageable despite the low temperature requirement.
3Manufacturing precision
If nitrogen-containing gas flow rate is adjusted, then by-product adhesion amount changes, but process optimization becomes more complex
Solution Approach 1:
The invention identifies the nitrogen-containing gas flow rate as a key controllable parameter that directly influences by-product adhesion amount. By establishing a quantitative relationship between flow rate and adhesion amount, the invention transforms a complex optimization problem into a more manageable parameter adjustment task, where precise recess width control can be achieved through systematic flow rate optimization.
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 the formation of recesses with desired widths, enhancing the precision and reliability of the plasma etching process for silicon-containing films, as demonstrated by correlations between etching parameters and recess dimensions.
Implementation Method 1
etching the silicon-containing film by using plasma generated from the processing gas
Implementation Method 2
adjusting a temperature of the substrate support to −20° C. or lower
Data Source
AI summary
An etching method includes: (a) providing a substrate including a silicon-containing film on a substrate support; (b) adjusting a temperature of the substrate support to −20° C. or lower; (c) supplying a processing gas including a nitrogen-containing gas, into the chamber; (d) etching the silicon-containing film by using plasma generated from the processing gas. A recess is formed by etching the silicon-containing film, and a by-product containing silicon and nitrogen adheres to a side wall of the recess. The etching method further includes (e) setting at least one etching parameter of the temperature of the substrate support and the flow rate of the nitrogen-containing gas included in the processing gas, to adjust the width of the bottom of the recess according to an adhesion amount of the by-product, before (b).