Backside Passivation for Substrate Outgassing
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Solution Overview
Problem
High-temperature wafer processing in RTP chambers faces issues with backside outgassing and sublimation, leading to contamination of chamber components and frequent recalibration or hardware replacement due to unaddressed sublimates or volatilized film components.
Innovation Solution
A backside passivation system using an elongate substrate support with a plasma source to form a passivating film, such as a nitride or oxide layer, on the backside of the substrate, preventing outgassing and sublimation by creating a cavity for plasma generation and applying it to the substrate without affecting the front side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the backside of the substrate is left unprotected during high-temperature processing, then the processing can proceed without additional steps, but outgassing and sublimation occur causing contamination of chamber components and chamber drift
Solution Approach 1:
The substrate processing is segmented into separate front-side and backside treatments. The backside passivation is performed as a distinct step using plasma exposure before front-side processing, isolating the protective function from the main processing sequence and preventing contamination without disrupting the primary manufacturing flow.
Solution Approach 2:
The backside passivation layer is formed in advance before the substrate enters the rapid thermal processing chamber. This preliminary plasma treatment creates a protective barrier that prevents outgassing and sublimation during subsequent high-temperature processing, eliminating the need for chamber cleaning or recalibration.
2Reliability
If a passivation layer is formed on the backside of the substrate, then outgassing and sublimation are prevented, but additional processing steps and time are required
Solution Approach 1:
The backside passivation step is merged with the existing substrate handling workflow. The plasma treatment is performed in a dedicated chamber using standard substrate supports and handling protocols, allowing the passivation to be integrated into the overall processing sequence without requiring separate handling or additional equipment.
3Manufacturing precision
If the substrate is heated for front-side processing, then the desired processing results are achieved, but backside materials outgas or sublime causing contamination
Solution Approach 1:
A protective passivation layer is applied to the backside of the substrate before high-temperature processing. This preliminary protective action counteracts the harmful outgassing and sublimation effects that would otherwise occur during front-side processing, allowing the substrate to be heated to required temperatures without contaminating chamber components.
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
Effectively mitigates sublimation and outgassing, reducing the need for frequent recalibration and hardware replacement by forming a protective passivation layer on the backside of the substrate, allowing continuous processing without chamber drift.
Implementation Method 1
a plasma source to form a passivation film on the back side of the substrate
Implementation Method 2
depositing a passivating film on the back side of the substrate by exposing the back side of the substrate to one or more of a reactive gas or a plasma
Data Source
AI summary
Provided apparatus and methods for back side passivation of a substrate. The systems comprise an elongate support with an open top surface forming a support ring so that when a substrate is on the support ring, a cavity is formed within the elongate support. A plasma generator is coupled to the cavity to generate a plasma within the cavity to deposit a passivation film on the back side of the substrate.