Injector Substrate Gap Control in Spatial ALD
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Solution Overview
Problem
As process chambers increase in size to accommodate larger substrates, controlling the gap between the injector assembly and the substrate during spatial atomic layer deposition becomes increasingly difficult, requiring methods and apparatus to maintain a tightly controlled gap between 0.1 and 2 mm for proper precursor separation.
Innovation Solution
The solution involves a processing chamber design with a gas distribution assembly and a susceptor assembly, where actuators with bearings are used to adjust the gap by applying pressure or creating fluid bearings to maintain the desired gap distance, with sensors and feedback circuits ensuring precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the process chamber size increases to accommodate larger substrates, then the substrate processing capacity is improved, but the gap control between the injector assembly and substrate deteriorates
Solution Approach 1:
The gap control system is segmented into multiple independent actuators distributed around the chamber perimeter, each controlling a specific region. This allows localized adjustment of the injector-substrate gap even as the overall chamber size increases, maintaining precision across larger substrate areas.
Solution Approach 2:
The system transitions from a static gap configuration to a dynamic one where actuators continuously adjust the injector assembly position. This dynamic control enables the system to maintain the required 0.1-2mm gap precision regardless of chamber or substrate size variations.
2Device complexity
If mechanical bearings are used to apply pressure for gap control, then the control mechanism is simple and robust, but friction and wear affect long-term precision
Solution Approach 1:
Traditional mechanical contact bearings are replaced with fluid bearings that use gas or liquid pressure to support and position the injector assembly. This substitution eliminates solid-to-solid friction and wear, maintaining gap control precision over extended operational periods while keeping the control mechanism relatively simple.
Solution Approach 2:
The system employs pneumatic or hydraulic actuators with fluid bearing interfaces to apply controlled pressure for gap maintenance. The fluid medium provides smooth, wear-free contact that preserves positioning accuracy while allowing simple pressure-based control.
3Manufacturing precision
If non-contact fluid bearings are used instead of mechanical bearings, then friction and wear are eliminated, but the system complexity and cost increase
Solution Approach 1:
The fluid bearing system is designed to be self-regulating, where the fluid pressure automatically adjusts to maintain the optimal gap. The system uses the process gases already present in the chamber to create the fluid bearing, eliminating the need for separate lubrication or cooling systems and reducing overall complexity.
Solution Approach 2:
The fluid bearing mechanism serves multiple functions: it provides frictionless support, enables precise positioning, and acts as a sealing interface. By combining these functions into a single system, the patent reduces overall device complexity despite using advanced non-contact bearing technology.
4Manufacturing precision
If multiple actuators are distributed around the chamber to improve gap control, then the gap uniformity is improved, but the device complexity increases
Solution Approach 1:
The actuator system is divided into multiple segmented units distributed around the chamber perimeter. Each actuator independently controls a specific angular sector, allowing localized gap adjustment. This segmentation enables uniform gap control across the entire substrate surface while keeping each individual actuator relatively simple.
Solution Approach 2:
Rather than using a single complex actuator, the system employs multiple simpler actuators that collectively provide the required control. This distributed approach achieves better gap uniformity through partial actions from multiple sources, with the total complexity remaining manageable due to the modularity of each unit.
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 effectively maintains a consistent gap between 0.1 and 2 mm, ensuring proper precursor separation and process control, even with larger substrates, enhancing the efficiency and accuracy of spatial atomic layer deposition.
Implementation Method 1
Upwardly directed force is provided to the susceptor assembly using at least one actuator positioned below the susceptor assembly to lift the susceptor assembly toward a gas distribution assembly
Implementation Method 2
the bearing is a non-contact fluid type bearing in which only a fluid makes contact with the bottom surface of the susceptor assembly
Implementation Method 3
One or more embodiments further comprise a sensor to measure the contact pressure between the susceptor assembly and the gas distribution assembly
Implementation Method 4
the heating assembly comprises a plurality of lamps directing radiant energy toward the bottom surface of the susceptor assembly
Implementation Method 5
the flow of gas creates a fluid bearing to push the wafer toward the gas distribution assembly
Data Source
AI summary
Described are apparatus and methods for processing a semiconductor wafer in which the gap between the wafer surface and the gas distribution assembly remains uniform and of known thickness. The wafer is positioned within a susceptor assembly and the assembly is lifted toward the gas distribution assembly using actuators. The wafer can be lifted toward the gas distribution assembly by creating a fluid bearing below and/or above the wafer.