Electrostatic Chuck Trenches to Prevent Backside Gas Hole Blockage
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Solution Overview
Problem
The erosion of mesas on electrostatic chucks in substrate processing equipment leads to blockage of backside cooling gas holes, resulting in non-uniform cooling and process shifts during substrate processing.
Innovation Solution
The design incorporates a substrate support with an electrostatic chuck featuring mesas and trenches, where backside gas openings extend through the chuck and terminate within the trenches, preventing blockage and maintaining uniform cooling even as mesas erode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If mesas are used to separate substrate from ESC surface, then backside cooling gas distribution is improved, but mesa erosion occurs over time causing cooling hole blockage
Solution Approach 1:
The invention introduces trenches as a new dimensional feature extending downward from the ESC upper surface. These trenches create additional vertical space below the mesa level, allowing cooling gas openings to terminate within the trench region rather than at the mesa tip. This dimensional change separates the cooling gas flow path from the eroding mesa surface, preventing blockage while maintaining effective substrate cooling through the trenches.
2Manufacturing precision
If mesas extend upward from ESC surface, then substrate positioning is improved, but friction and chemical exposure cause mesa erosion
Solution Approach 1:
The invention segments the substrate support function into distinct regions: mesas for substrate positioning and contact, and trenches for cooling gas flow. By separating these functions spatially, the mesas can maintain their positioning function while the trenches protect the cooling infrastructure from erosion. The trenches act as protected channels that are not directly exposed to substrate friction and chemical environment.
3Temperature
If cooling gas openings extend through ESC, then substrate cooling is achieved, but erosion causes non-uniform gas distribution
Solution Approach 1:
The invention performs preliminary action by creating trenches before the erosion problem becomes critical. The trenches are pre-formed structures that anticipate future mesa erosion. By establishing these protective channels in advance, the system ensures that even as mesas erode over time, the cooling gas openings remain unblocked and gas distribution uniformity is maintained throughout the ESC lifetime.
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 design extends the lifetime of the electrostatic chuck by ensuring consistent backside cooling and preventing process shifts due to erosion, maintaining uniform gas distribution and substrate cooling.
Implementation Method 1
Electrostatic chucking forces are generated by charge separation induced in the substrate by the ESC, wherein oppositely charged electrodes are disposed in the ESC, thereby securing the substrate to a substrate support surface of the substrate support.
Implementation Method 2
The mesas separate a back side of the substrate from the upper surface of the ESC so that backside cooling gas may be delivered to the substrate.
Data Source
AI summary
Embodiments of substrate supports for use in process chambers are provided herein. In some embodiments, a substrate support includes: an electrostatic chuck (ESC) having an upper surface and a plurality of mesas extending upward from the upper surface and a plurality of trenches extending downward from the upper surface and into the ESC, wherein the ESC includes a plurality of backside gas openings extending through the ESC and terminating within at least some of the plurality of trenches; and one or more chucking electrodes disposed in the ESC.