Sacrificial Coating for Gas Distributor Decontamination
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Solution Overview
Problem
The buildup of group III nitride deposits on gas distributors in deposition chambers leads to contamination and reduced efficiency in the production of semiconductor devices, as these deposits can flake off and adhere to substrates, compromising the quality and yield of devices like LEDs and laser diodes.
Innovation Solution
A method involving the formation of a sacrificial coating on the gas distributor, followed by exposure to an activated halogen-containing gas to etch away the deposits, and subsequent heat treatment to convert and remove the deposits as volatile species, ensuring effective cleaning and preventing re-deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a sacrificial coating is applied to the gas distributor, then the uniformity and quality of semiconductor films is improved by preventing particle dislodgement, but the device complexity increases due to additional coating and cleaning steps
Solution Approach 1:
A sacrificial coating (such as silicon nitride or aluminum nitride) is applied to the gas distributor surface before deposition begins. This preliminary action creates a controlled interface that prevents direct contact between deposits and the gas distributor, eliminating particle dislodgement and ensuring consistent film quality throughout the deposition process.
Solution Approach 2:
The sacrificial coating is designed to be easily removable through in-situ cleaning processes using halogen-containing gases. Rather than requiring complex mechanical cleaning or replacement of the gas distributor, the coating serves its protective function and is then discarded through chemical etching, simplifying the overall maintenance process while maintaining high film quality.
2Reliability
If in-situ cleaning with halogen-containing gas is performed, then contamination risk is reduced and chamber longevity is increased, but loss of substance occurs due to etching of the sacrificial coating
Solution Approach 1:
The sacrificial coating is intentionally designed to be consumed during the cleaning process. Halogen-containing gases (such as chlorine or bromine) chemically etch the coating material, converting it into volatile halide compounds that are pumped away. This controlled discarding of the coating achieves thorough cleaning of the gas distributor surface while the loss of coating material is acceptable given its relatively low cost and the benefits of contamination prevention.
Solution Approach 2:
The cleaning process utilizes specific parameters of halogen-containing gases (reactivity, volatility of resulting halides) to achieve selective etching. By controlling temperature, pressure, and gas flow rates, the process removes the sacrificial coating and any deposited materials efficiently while minimizing damage to the underlying gas distributor substrate.
3Stability of the object's composition
If the gas distributor is kept at low temperature to avoid gas decomposition, then gas stability is maintained, but deposits build up on the gas distributor over time
Solution Approach 1:
The sacrificial coating is applied to the gas distributor surface before deposition begins. This preliminary protective layer acts as a barrier that prevents reaction products from directly depositing on the gas distributor, allowing the gas distributor to remain at low temperature for gas stability while the coating accumulates controlled deposits that can be easily removed later.
Solution Approach 2:
The sacrificial coating serves as an intermediary layer between the reaction zone and the gas distributor. It absorbs the brunt of deposit formation, preventing direct contamination of the gas distributor. The coating material is selected to be more reactive toward deposit materials than the gas distributor substrate, ensuring that deposits form preferentially on the coating rather than on the expensive gas distributor 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
This approach significantly reduces contamination by efficiently removing deposits, maintaining chamber cleanliness, and enhancing the uniformity of precursor mixing, thereby improving the quality and longevity of semiconductor devices.
Implementation Method 1
exposing the group III nitride deposits and the sacrificial coating to an activated halogen containing gas, and etching the sacrificial coating and the group III nitride deposits
Implementation Method 2
reacting the halogen containing gas with the group III nitride deposits to form volatile species
Implementation Method 3
exposing the gas distributor to an active nitrogen containing gas
Data Source
AI summary
A method and apparatus for removing deposition products from internal surfaces of a processing chamber, and for preventing or slowing growth of such deposition products. A halogen containing gas is provided to the chamber to etch away deposition products. A halogen scavenging gas is provided to the chamber to remove any residual halogen. The halogen scavenging gas is generally activated by exposure to electromagnetic energy, either inside the processing chamber by thermal energy, or in a remote chamber by electric field, UV, or microwave. A deposition precursor may be added to the halogen scavenging gas to form a deposition resistant film on the internal surfaces of the chamber. Additionally, or alternately, a deposition resistant film may be formed by sputtering a deposition resistant metal onto internal components of the processing chamber in a PVD process.