ALD Susceptor Gap Control via Camera and Capacitance Sensors
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving tight control over the gap between the wafer and deposition source in atomic layer deposition (ALD) processes, particularly for large wafers and varying temperatures, which affects uniformity and throughput, leading to increased costs due to low deposition rates and complex maintenance requirements.
Innovation Solution
A deposition apparatus comprising a gas distribution assembly, a susceptor assembly, and cameras with a controller to accurately measure and adjust the gap between the susceptor and gas distribution assembly, using capacitance sensors and feedback circuits to ensure precise control and uniformity across the wafer surface, and temperature monitoring for thermal adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ALD process is used to achieve superior step coverage and conformal deposition, then manufacturing precision is improved, but productivity deteriorates due to low deposition rate requiring 10-200 minutes per chamber
Solution Approach 1:
The system divides the deposition process into multiple parallel chambers, each capable of independent ALD processing. By segmenting the workload across multiple chambers that can operate simultaneously, the system maintains the high precision ALD process while increasing overall throughput and reducing the time required to process batches of substrates.
2Productivity
If batch processing is used to increase throughput by processing multiple substrates simultaneously, then productivity is improved, but manufacturing precision deteriorates due to difficulty in controlling gap uniformity across large wafers
Solution Approach 1:
The system incorporates sensors and control mechanisms that continuously monitor the gap between the susceptor and deposition source during batch processing. Real-time feedback allows the system to detect and correct gap non-uniformities across large wafers, maintaining manufacturing precision while enabling batch processing of multiple substrates simultaneously.
Solution Approach 2:
The system employs dynamic adjustment mechanisms that can modify the gap distance between the susceptor and deposition source during the deposition process. This dynamic control allows the system to compensate for variations in wafer size and position, maintaining uniform deposition across all substrates in the batch while maximizing throughput.
3Manufacturing precision
If tight control of gap distance is implemented to meet composition and thickness uniformity requirements, then manufacturing precision is improved, but device complexity increases due to need for precise monitoring and adjustment mechanisms
Solution Approach 1:
The system incorporates self-adjusting mechanisms that automatically maintain the optimal gap distance between the susceptor and deposition source. Through self-service features such as automatic positioning and real-time compensation, the system achieves tight gap control and uniform deposition without requiring complex external monitoring and adjustment mechanisms, thereby reducing overall system complexity.
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 solution enables precise control of the gap and temperature, enhancing deposition uniformity and throughput, reducing costs by optimizing the processing efficiency and maintaining the quality of semiconductor devices.
Implementation Method 1
A camera has a field of view including the edge of the susceptor assembly
Implementation Method 2
A plurality of capacitance sensors are positioned on the front surface of the gas distribution assembly directed toward the top surface of the susceptor assembly. Each of the capacitance sensors provides an electrical signal which is proportional to the distance of the top surface of the susceptor assembly to the capacitance sensor
Data Source
AI summary
Apparatus and methods of measuring and controlling the gap between a susceptor assembly and a gas distribution assembly are described. Apparatus and methods for positional control and temperature control for wafer transfer purposes are also described.