Recess Gas Treatment Using Process Gas Pressure Equalization
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Solution Overview
Problem
Existing gas treatment methods struggle to achieve uniform treatment at both the top and bottom portions of substrates with high aspect ratio recesses, leading to top-bottom loading issues during etching processes, where the etching amount is smaller at the bottom portion compared to the top portion.
Innovation Solution
The method involves using the process gas, such as HF and NH3, as part of the pressure adjustment gas to increase pressure inside the chamber, ensuring uniform gas treatment by supplying these gases during the pressure adjustment step, which also initiates the etching reaction, thereby ensuring consistent etching across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pressure adjustment is performed using inert gas only, then the etching reaction is delayed until the etching step, but this causes non-uniform etching at top and bottom portions of high aspect ratio recesses
Solution Approach 1:
The patent merges the pressure adjustment step and etching step by supplying process gas (HF and/or NH3) during pressure adjustment, so that both pressure equalization and etching reaction occur simultaneously. This eliminates the need for separate gas supply control sequences and achieves uniform etching at top and bottom portions of high aspect ratio recesses.
Solution Approach 2:
The patent performs preliminary etching action during the pressure adjustment step by supplying process gas before the dedicated etching step. This preliminary action ensures that etching begins uniformly across the substrate surface, including hard-to-reach bottom portions of high aspect ratio recesses, before the main etching phase.
2Manufacturing precision
If process gas is supplied during pressure adjustment, then etching reaction starts earlier improving uniformity, but this requires precise control of pressure and gas flow
Solution Approach 1:
The patent changes the parameters of pressure adjustment by transitioning from supplying only inert gas to supplying process gas (HF and/or NH3) during pressure adjustment. This parameter change enables the etching reaction to occur during pressure equalization, improving uniformity while the control system manages the additional complexity through automated parameter coordination.
3Ease of operation
If separate pressure adjustment and etching steps are used, then process control is simplified, but etching uniformity at top and bottom of recesses deteriorates
Solution Approach 1:
The patent combines two previously separate steps (pressure adjustment and etching) into a single integrated process where process gas is supplied during pressure adjustment. This merging eliminates the interface problem between steps and ensures continuous, uniform etching from top to bottom of high aspect ratio recesses.
Solution Approach 2:
The patent ensures continuity of the etching action by maintaining process gas supply throughout the pressure adjustment period. This continuous action prevents interruption of the etching reaction, ensuring uniform material removal across the substrate surface without the non-uniformity that occurs when etching starts after pressure adjustment completes.
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 allows for uniform etching at both the top and bottom portions of the recess, reducing top-bottom loading and enhancing the control over the etching process by integrating the pressure adjustment and etching steps, resulting in improved etching uniformity and controllability.
Implementation Method 1
performing the gas treatment on a side wall of the recess of the substrate by causing a treatment reaction by a process gas in the chamber
Implementation Method 2
adjusting a pressure inside the chamber to a predetermined pressure by supplying a pressure adjustment gas into the chamber in an evacuated state to increase the pressure inside the chamber
Data Source
AI summary
A gas treatment method of performing a gas treatment on a substrate having a recess includes: disposing the substrate having the recess in a chamber; adjusting a pressure inside the chamber to a predetermined pressure by supplying a pressure adjustment gas into the chamber in an evacuated state to increase the pressure inside the chamber; and subsequently, performing the gas treatment on a side wall of the recess of the substrate by causing a treatment reaction by a process gas in the chamber, wherein the process gas causing the treatment reaction is used as at least a part of the pressure adjustment gas in the adjusting the pressure.