ALD Shower Head Pressure Control for Faster Film Deposition
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Solution Overview
Problem
Existing atomic layer deposition (ALD) methods face challenges in shortening the cycle time for film formation on a substrate, particularly in single wafer type film forming apparatuses, due to the time required to increase and decrease chamber pressure, which affects productivity.
Innovation Solution
The film forming apparatus incorporates a high-speed valve system for controlling gas flow and pressure in the chamber, including a pressure control gas supply and a direct gas exhaust connection to the shower head, to optimize the timing of gas supply and exhaust operations, thereby reducing cycle time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional pressure control methods are used in ALD, then film deposition quality is maintained, but cycle time is extended due to slow pressure increase and decrease
Solution Approach 1:
The gas supply system is segmented into multiple independent pathways: a first gas supply pipe with first valve for chamber pressure control, and a second gas supply pipe with second valve for shower head pressure control. This segmentation allows independent optimization of each pressure control pathway, enabling faster cycle times while maintaining film quality.
Solution Approach 2:
The system dynamically adjusts pressure in different regions (chamber and shower head) independently through separate valve control. The shower head pressure can be rapidly increased and decreased without affecting chamber pressure, enabling dynamic optimization of the deposition cycle and reducing overall cycle time.
2Loss of time
If high-speed valve system is implemented, then cycle time is reduced, but device complexity increases
Solution Approach 1:
The gas supply system is divided into separate modular units: chamber gas supply (first pipe, first valve) and shower head gas supply (second pipe, second valve). This modular segmentation makes the complex system easier to control and maintain, as each unit can be independently optimized and troubleshooted.
Solution Approach 2:
The separate valve and pipe system serves multiple functions: it controls chamber pressure, controls shower head pressure, enables rapid gas flow switching, and maintains film deposition quality. This multi-functionality justifies the added complexity by delivering multiple benefits simultaneously.
3Loss of time
If pressure control is optimized for speed, then cycle time decreases, but film deposition uniformity may be compromised
Solution Approach 1:
The system dynamically controls pressure in the shower head independently from the chamber, allowing rapid pressure changes that optimize gas flow and residence time. This dynamic control ensures uniform film deposition even during fast cycle transitions, maintaining manufacturing precision while reducing cycle time.
Solution Approach 2:
Different regions of the system (chamber vs. shower head) are given different pressure control characteristics optimized for their specific functions. The shower head receives aggressive pressure control for speed, while the chamber maintains stable pressure for quality, achieving both fast cycling and uniform deposition.
Data Source
AI summary
A film forming apparatus of embodiments includes: a chamber including a sidewall; a shower head provided in an upper part of the chamber; a holder provided in the chamber holding a substrate; a first gas supply pipe supplying a first gas to the shower head; a first valve provided in the first gas supply pipe; at least one gas supply portion provided in a region of the chamber other than the shower head; a second gas supply pipe supplying a second gas to the at least one gas supply portion; a second valve provided in the second gas supply pipe; a gas exhaust pipe exhausting a gas from the chamber; and an exhaust device connected to the gas exhaust pipe.