Process Chamber Lid Backside Pumping for Uniform ALD Deposition
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in achieving uniform deposition of films on high aspect ratio features due to reactive gases becoming trapped between the lid plate and showerhead, leading to non-uniformity and step coverage issues.
Innovation Solution
A process chamber lid assembly with a gas dispersion channel and a gas distribution plate featuring a contoured bottom surface and apertures, along with a pumping channel and backside pumping capability, to enhance gas flow uniformity and efficiently remove residual gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a funnel lid with multiple injectors is used to distribute precursor gases, then gas distribution uniformity is improved, but reactive gases become trapped between the lid plate and showerhead causing non-uniform deposition
Solution Approach 1:
The patent extracts the harmful trapped reactive gases from the chamber by introducing a pumping channel that communicates with the space between the lid plate and showerhead. This allows the harmful gases to be removed through a dedicated pathway, preventing them from causing non-uniform deposition while preserving the beneficial gas distribution structure.
Solution Approach 2:
The pumping channel acts as an intermediary structure that mediates between the gas distribution system and the vacuum system. It provides a controlled pathway for removing trapped reactive gases without disrupting the precursor gas distribution through the funnel lid and injectors, thus resolving the conflict between gas distribution and gas removal.
2Manufacturing precision
If sequential pulses of reactant gases are introduced for ALD processing, then monolayer formation is achieved, but residual reactants cause gas phase reactions and non-uniform deposition
Solution Approach 1:
The patent implements continuous pumping action during the ALD process to continuously remove residual reactant gases from the chamber. This continuous removal prevents the accumulation of excess reactants that would otherwise lead to gas phase reactions, while allowing the sequential pulse process to continue uninterrupted for monolayer formation.
Solution Approach 2:
The pumping channel extracts residual reactant gases from the chamber between pulses of the first and second reactant gases. This extraction prevents the harmful gas phase reactions that would occur if excess reactants remained in the chamber, while preserving the beneficial sequential pulse structure for controlled monolayer deposition.
3Productivity
If the lid plate and showerhead are positioned close together for efficient gas delivery, then gas distribution is improved, but reactive gases become trapped causing deposition non-uniformity
Solution Approach 1:
The pumping channel serves as an intermediary structure that enables the lid plate and showerhead to be positioned close together for efficient gas delivery while simultaneously providing a pathway to remove trapped reactive gases. This mediator structure resolves the conflict between close positioning for efficiency and gas removal for uniformity.
Solution Approach 2:
The pumping channel extracts trapped reactive gases from the narrow space between the closely positioned lid plate and showerhead. This allows the components to be positioned close together for efficient gas delivery without suffering from the harmful effect of trapped gases causing non-uniform deposition.
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 solution provides improved uniformity of film deposition and step coverage on substrate surfaces, effectively addressing non-uniformity and residual gas issues.
Implementation Method 1
backside pumping capability to enhance gas flow uniformity and efficiently remove residual gases
Implementation Method 2
gas dispersion channel that extends along a central axis of the housing... gas distribution plate... configured to form a pumping channel between the gas distribution plate and the lid plate
Data Source
AI summary
Process chamber lid assemblies and process chambers comprising same are described. The lid assembly has a housing with a gas dispersion channel in fluid communication with a lid plate. A contoured bottom surface of the lid plate defines a gap to a top surface of a gas distribution plate. A pumping channel is formed between an upper outer peripheral contour of the gas distribution plate and the lid plate.