Pre-clean Chamber Plasma Cleaning for TiSix-EPI Interface
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Solution Overview
Problem
In semiconductor manufacturing, residual oxygen and fluorine gases in the pre-clean and degas chamber can contaminate the TiSix-EPI interface, leading to increased resistance and defects, thereby reducing yield.
Innovation Solution
A chamber cleaning process involving a three-step plasma treatment using an oxygen/argon mixture followed by an inert gas, such as argon, to remove residual oxygen and improve the TiSix-EPI interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-clean process is performed in a plasma vapor deposition chamber, then water molecules, hydrocarbons, and particles are removed from the substrate, but residual oxygen and fluorine gases contaminate the TiSix-EPI interface
Solution Approach 1:
The patent applies preliminary action by performing a pre-clean process before the main deposition process to remove contaminants from the substrate. This preliminary cleaning step prepares the substrate for subsequent processing while managing the introduction of residual gases through controlled chamber cleaning sequences.
Solution Approach 2:
The patent uses an inert atmosphere approach by introducing argon gas into the chamber to displace and remove residual oxygen and fluorine gases. The argon serves as an inert gas that creates a cleaner environment, allowing the harmful residual gases to be evacuated from the chamber before the TiSix-EPI deposition process.
2Manufacturing precision
If residual oxygen remains in the chamber after pre-clean, then the TiSix-EPI interface is contaminated, but complete gas removal requires additional cleaning steps
Solution Approach 1:
The patent applies parameter changes by varying the gas composition and pressure parameters during the cleaning process. The system transitions from a pre-clean state to a post-clean state by changing gas flow rates, pressure levels, and gas composition (introducing argon), thereby achieving complete gas removal through controlled parameter adjustments rather than fixed procedural steps.
Solution Approach 2:
The patent uses argon gas as an intermediary substance to facilitate the removal of residual oxygen and fluorine. The argon acts as a mediator that displaces the harmful residual gases from the chamber environment, enabling their subsequent evacuation and achieving clean interface formation without requiring complex direct removal mechanisms.
3Reliability
If multiple cleaning steps are implemented to remove residual gases, then oxygen and fluorine contamination is reduced, but process time increases
Solution Approach 1:
The patent applies continuity of useful action by integrating the chamber cleaning process into the continuous deposition workflow. The cleaning steps are performed sequentially without interrupting the overall manufacturing flow, and the argon gas introduction is timed to coincide with or immediately follow the pre-clean process, ensuring continuous productive action while achieving complete gas removal.
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 proposed solution effectively reduces residual oxygen contamination, improving the TiSix-EPI interface and enhancing semiconductor device production by reducing defects and increasing yield.
Implementation Method 1
cleaning the process chamber using a first gas of oxygen and an inert gas; generating plasma in the process chamber using the first gas
Implementation Method 2
generating plasma in the process chamber using the second gas; cleaning the process chamber using the second gas
Data Source
AI summary
A system and method for cleaning a preclean process chamber in between wafer processing. The internal pressure of the preclean process chamber is reduced to a first pressure and a first gas that consists of oxygen and an inert or noble gas, is introduced into the chamber. Plasma is generated within the preclean process chamber using the first gas at the first pressure. Internal pressure is then reduced to a second pressure, less than the first, and the first gas is continued into the chamber. Plasma is then generated using the first gas at the second pressure. Thereafter, a second gas, consisting of an oxygen-free inert or noble gas, is introduced into the chamber at the second pressure, following which plasma is generated within the chamber using only the second gas.