Plasma Processing Apparatus Gas Supply Segmentation
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Solution Overview
Problem
Plasma processing apparatuses with a post-mix structure face issues with inert gases acting as additive gases during etching, leading to decreased mask selectivity and increased Line Edge Roughness (LER) due to the inert gases supplied through the aminosilane gas supply pipe during Atomic Layer Deposition (ALD) and etching processes.
Innovation Solution
A plasma processing apparatus with a second gas supply part that directs precursor gases to an exhaust space, preventing them from reacting with process gases converted to plasma, and using a baffle plate to shield plasma in the process space, ensuring that inert gases do not act as additive gases during etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a post-mix structure is used to supply aminosilane based gas separately from other process gases, then the aminosilane based gas can be supplied without reacting with other process gases in the pipe, but inert gas supplied through the same pipe acts as an additive gas during etching, causing decreased mask selectivity and increased Line Edge Roughness
Solution Approach 1:
The gas supply system is divided into two separate paths: one for aminosilane based gas and another for other process gases. This segmentation prevents the inert gas supplied during ALD from mixing with the etching plasma, thereby eliminating the harmful additive effect while maintaining the benefits of the post-mix structure for preventing reaction product deposition.
Solution Approach 2:
A dedicated inert gas supply path acts as an intermediary system that separates the ALD process gas supply from the etching process gas supply. This intermediary structure allows inert gas to be supplied during ALD without it becoming an unwanted additive during subsequent etching processes, thus resolving the contradiction between reliable gas supply and precise etching.
2Ease of operation
If other process gas is supplied without aminosilane based gas, then the aminosilane based gas supply pipe is unused, but the other process gas flows into the aminosilane based gas supply pipe, requiring additional inert gas supply to prevent contamination
Solution Approach 1:
The gas supply system is segmented into independent channels, allowing each gas type to be controlled separately. This segmentation enables flexible operation where each gas supply path can be independently activated or deactivated, eliminating the need for complex cross-contamination prevention mechanisms while maintaining operational flexibility.
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 configuration prevents the inert gases from interfering with the etching process, maintaining mask selectivity and reducing LER, thereby achieving preferable etching shapes.
Implementation Method 1
a radio frequency power source that converts the first gas to plasma
Implementation Method 2
a shield part that blocks the first gas converted to plasma
Data Source
AI summary
A plasma processing apparatus includes a process chamber, and a pedestal provided in the process chamber and configured to hold a substrate. The plasma processing apparatus includes a first gas supply part configured to be able to supply a first gas from a location facing the pedestal, and a radio frequency power source configured to convert the first gas to plasma. A shield part to block the first gas converted to plasma is provided around the pedestal. The plasma processing apparatus further includes an evacuation part configured to evacuate the process chamber through the shield part, and a second gas supply part configured to be able to supply a second gas to a space between the shield part and the evacuation part.