Substrate Support Mesa Depth Layout for Temperature Uniformity
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Solution Overview
Problem
Existing substrate processing systems face challenges in achieving uniform temperature distribution across substrates during high-power etch processes, leading to temperature variations of 5-20° C. due to non-uniform plasma and cooling patterns.
Innovation Solution
The method involves determining a temperature distribution pattern across the substrate or support plate, using this pattern to determine the number and patterns of masks to apply to the support plate, and performing machining processes to create mesas and recessed areas that compensate for temperature non-uniformities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional substrate support with uniform geometry is used, then the structure is simple and easy to manufacture, but temperature distribution across the substrate becomes non-uniform (5-20°C variation)
Solution Approach 1:
The substrate support employs varying mesa depths across different radial positions to create localized thermal characteristics. Inner mesas have different depths than outer mesas, allowing each region to compensate for local temperature non-uniformities. This local quality variation enables temperature uniformity across the substrate without requiring a completely different support structure.
Solution Approach 2:
The invention changes the geometric parameter of mesa depth radially across the substrate support. By varying the depth parameter from inner to outer regions, the thermal mass and heat dissipation characteristics are adjusted locally. This parameter change allows compensation for temperature variations while maintaining a relatively simple overall structure that can be manufactured using standard techniques.
2Temperature
If multiple machining processes are performed to create varying mesa depths, then temperature uniformity is improved, but manufacturing complexity and time increase
Solution Approach 1:
Masks are applied to the substrate support before machining to pre-determine which areas require material removal. This preliminary action allows the varying mesa depths to be created in a systematic manner, reducing the number of iterative machining steps needed. The masks guide the machining process to achieve the desired depth profile more efficiently.
Solution Approach 2:
The substrate support fabrication is divided into discrete machining steps, with each step removing material to a specific depth in designated areas. By segmenting the machining process into controlled stages with mask guidance, the complex varying depth profile is achieved through manageable steps rather than a single complex operation, improving manufacturability.
3Manufacturing precision
If masks are applied to control machining areas, then precise mesa geometry is achieved, but the manufacturing process becomes more complex
Solution Approach 1:
Masks serve as intermediary elements that simplify the machining process by defining protected areas. Rather than attempting to control material removal through complex machining path programming, the masks physically block access to areas that should not be machined. This intermediary approach achieves precise mesa geometry with relatively simple machining operations.
Solution Approach 2:
The mask patterns are designed to copy or replicate the desired final mesa geometry. By creating masks that match the target depth profile, the machining process automatically produces the correct geometry without requiring complex real-time control. The masks act as physical templates that guide the material removal process.
Data Source
AI summary
A method is provided and includes: determining a temperature distribution pattern across a substrate or a support plate of a substrate support; determining, based on the temperature distribution pattern, a number of masks to apply to a top surface of the support plate, where the number of masks is greater than or equal to two; and determining patterns of the masks based on the temperature distribution pattern; and applying the masks over the top surface. The method further includes: performing a first machining process to remove a portion of the support plate unprotected by the masks to form first mesas and first recessed areas between the first mesas; removing a first mask from the support plate; performing a second machining process to form second recessed areas and at least one of second mesas or a first seal band area; and removing a second mask from the support plate.