Bidirectional Indexing Heads for Precise Substrate Gap Control
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Solution Overview
Problem
In modern semiconductor processes, the inability to adjust the gap between a substrate and a pedestal in a processing chamber is a significant drawback, particularly in optimizing chamber conditions for creating nanosized structures in plasma-enhanced chemical vapor deposition (PECVD).
Innovation Solution
A bidirectional indexing apparatus with a rotatable plate and camming pins is used to adjust the gap between a substrate and a pedestal, allowing for precise control of the substrate's height and orientation through a sequence of camming pin actuations, driven by hydraulic linear pistons and controlled by a controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed pedestal structure is used in the substrate processing chamber, then the device complexity is reduced and manufacturing is easier, but the ability to adjust the gap between substrate and pedestal is lost, which limits optimization of chamber conditions for nanosized structure creation
Solution Approach 1:
The pedestal structure is transformed from a fixed static configuration to a dynamic adjustable system. The indexing apparatus enables the pedestal to change its position and orientation dynamically, allowing gap adjustment between substrate and pedestal while maintaining structural integrity through controlled mechanical movement.
Solution Approach 2:
The indexing apparatus is divided into multiple independent indexing heads, each capable of individual or coordinated operation. This segmentation allows precise control of gap adjustment through distributed actuation points, reducing the complexity burden on any single component while achieving overall system adaptability.
2Manufacturing precision
If multiple camming pins are used to achieve precise bidirectional indexing, then the manufacturing precision and control accuracy are improved, but the device complexity and number of components increase
Solution Approach 1:
Multiple camming pins are integrated into a coordinated system where they work together on a shared rotatable plate. The pins are positioned at specific angular intervals and can be actuated in sequence or simultaneously, merging their individual indexing actions into a unified precise bidirectional rotation mechanism that reduces overall system complexity.
Solution Approach 2:
The rotatable plate serves as an intermediary element that translates the linear actuation of multiple camming pins into rotational indexing motion. This mediator component allows the camming pins to operate independently while achieving coordinated precise control, reducing the complexity of direct multi-point actuation.
3Ease of operation
If hydraulic linear pistons are used to actuate camming pins in sequence, then the ease of operation and automation are improved, but the use of energy and system complexity increase
Solution Approach 1:
Hydraulic linear pistons are employed to actuate the camming pins, providing controlled linear motion that translates into precise rotational indexing. The hydraulic system enables automated operation with controlled energy delivery, allowing sequence actuation of multiple pins while managing energy consumption through fluid power efficiency.
Solution Approach 2:
The camming pins are actuated in a sequential periodic manner rather than simultaneously, with each pin operating in turn during a complete indexing cycle. This periodic actuation pattern reduces peak energy demands on the hydraulic system while maintaining automated control and precise indexing accuracy.
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
Enables precise adjustment of the gap and orientation of the substrate, enhancing the ability to optimize chamber conditions for nanosized structure formation in PECVD processes.
Implementation Method 1
Each of the profiled pockets may include a profiled surface that acts as a camming surface, or cam
Implementation Method 2
The rotating plate of each indexing head in the indexing apparatus may act on a threaded screw or other device to impart movement to a substrate supported on a pedestal
Implementation Method 3
the camming pins are actuated by a fluid pressure difference (for example, by one or more hydraulic linear pistons controlled by a controller)
Data Source
AI summary
In an example embodiment, a bidirectional indexing apparatus includes a plurality of bidirectional indexing heads that can operate independently of each other or in concert to adjust a gap between a substrate and a pedestal in a substrate processing chamber. In some embodiments, a bidirectional indexing head comprises a base; a rotatable plate rotatable relative to the base, the rotatable plate including a plurality of profiled pockets each defining a camming surface therein; and a plurality of camming pins, each disposed to act on the camming surface of a respective profiled pocket to move the rotatable plate in a first or second rotatable direction when actuated.