Ceramic Heated Substrate Support for Uniform Wafer Temperature
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Solution Overview
Problem
Existing substrate support assemblies in semiconductor manufacturing face challenges in achieving uniform temperature control due to chamber asymmetries and non-homogeneous construction, leading to non-uniform heat transfer and processing results, particularly affecting etch rates and critical dimension uniformity.
Innovation Solution
A substrate support assembly with a ceramic electrostatic chuck, embedded heaters, and a metal cooling base, combined with a thermally insulating layer and controlled heat transfer fluid, enables precise temperature uniformity across the substrate surface, allowing for both lateral and azimuthal uniformity and selective etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional substrate support assemblies are used, then the structure is simple and easy to manufacture, but temperature uniformity across the substrate surface deteriorates due to chamber asymmetries and non-homogeneous construction
Solution Approach 1:
The substrate support assembly is divided into distinct functional segments: a ceramic chuck body for electrical insulation and substrate support, embedded heating elements for temperature control, and a separate cooling base. This segmentation allows each component to be optimized for its specific function while working together to achieve uniform temperature distribution across the substrate surface.
Solution Approach 2:
The assembly utilizes composite construction by combining ceramic material for the chuck body with metallic heating elements and a cooling base. The ceramic provides electrical insulation and thermal stability, while the metallic components provide controlled heat transfer. This composite approach enables precise temperature uniformity that cannot be achieved with single-material constructions.
2Manufacturing precision
If electrostatic chuck with non-homogeneous construction is used, then chucking functionality is achieved, but heat transfer uniformity deteriorates due to gas holes, lift pin holes, and offset electrodes
Solution Approach 1:
The ceramic chuck body incorporates locally optimized features including gas holes and lift pin holes positioned at specific locations to maintain chucking functionality. The heating elements are embedded within the ceramic matrix to provide uniform heat distribution through the thickness of the chuck, compensating for the non-uniform heat transfer paths created by the gas holes and lift pin holes.
Solution Approach 2:
The ceramic chuck body acts as an intermediary between the heating elements and the substrate. It distributes heat uniformly across its top surface despite the presence of gas holes and lift pin holes, thereby decoupling the chucking functionality requirements from the heat transfer uniformity requirements. The ceramic material's thermal properties enable it to smooth out local variations and provide uniform temperature at the substrate interface.
3Manufacturing precision
If conventional heating schemes are used, then heating capability is provided, but temperature control precision deteriorates due to lateral and azimuthal non-uniformity
Solution Approach 1:
The heating system incorporates dynamically controllable heating elements with independently adjustable power levels. This allows the system to actively compensate for lateral and azimuthal non-uniformities by adjusting the heating power in different regions, achieving precise temperature control and uniformity across the substrate surface despite the complex geometry of the chuck body.
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
The assembly achieves temperature uniformity within 1°C across the substrate, enhancing etch rate control and critical dimension consistency, compensating for chamber non-uniformities and improving processing outcomes.
Implementation Method 1
At least a first heater is disposed on the bottom surface outside the body
Implementation Method 2
The body made from ceramic
Implementation Method 3
a cooling base having a body made from a metal. The cooling body having an upper cooling body surface and a lower cooling body surface wherein the upper cooling body surface has a flatness of less than about 10 microns
Data Source
AI summary
Implementations described herein provide a substrate support assembly which enables temperature uniformity across a workpiece surface. In one embodiment, a substrate support assembly is provided that includes a body. The body made from ceramic. The body having a workpiece support surface and a mounting surface. The workpiece support surface and the bonding chuck body surface having a flatness of less than 10 microns. A first heater is disposed on the bottom surface outside the body. A bonding layer is disposed over the first heater, wherein the bonding layer is electrically insulating and a cooling base having a body made from a metal. The cooling body having an upper cooling body surface and a lower cooling body surface wherein the upper cooling body surface is less than about 10 microns flat.