Electrostatic Chuck Preheat and Rounded Supports for Backside Protection
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Solution Overview
Problem
Electrostatic chucks cause backside puncture and scratch damage to semiconductor substrates during processing due to electrostatic forces and thermal expansion, leading to lithographic defects and reduced production yield.
Innovation Solution
A substrate support with rounded edge features and a temperature control device, combined with a preheat treatment using inert gases in a plasma or process gas environment, to minimize substrate backside damage by reducing friction and thermal expansion during electrostatic chucking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrostatic forces are applied to hold the substrate against the electrostatic chuck, then substrate holding stability is improved, but backside puncture damage increases
Solution Approach 1:
The substrate support features are formed with rounded edges instead of sharp edges. This curvature distributes the electrostatic pressure over a larger area and eliminates stress concentration points, thereby preventing substrate puncture damage while maintaining holding stability
Solution Approach 2:
The substrate support features have different geometries at different locations - the rounded edges at the periphery and the supporting surface in the center. This local variation in geometry optimizes both the holding force distribution and the prevention of edge-related puncture damage
2Temperature
If high processing temperatures are applied, then processing capability is improved, but thermal expansion causing substrate sliding increases
Solution Approach 1:
Rounded edges on the substrate support features reduce friction during substrate thermal expansion and sliding, minimizing scratch damage while allowing the substrate to be held at high processing temperatures
Solution Approach 2:
The substrate support features are pre-formed with rounded edges before the substrate is placed, creating a low-friction surface that prevents scratch damage during subsequent thermal expansion and sliding movements
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 solution significantly reduces backside damage by up to 80% and improves lithography process yield, addressing the cost burden of lithographic operations in integrated circuit manufacturing.
Implementation Method 1
thermal expansion of the substrate during high processing temperatures can result in sliding of the backside of the substrate along the electrostatic chuck
Implementation Method 2
the backside of a substrate, such as a semiconductor substrate, is held to the face of the electrostatic chuck by electrostatic forces that are generated from one or more electrodes embedded in the electrostatic chuck
Implementation Method 3
The plasma preheat treatment includes flowing one or more inert gases into a process volume at a flow rate between about 1000 sccm and about 3000 sccm, generating a plasma from the inert gases, and maintaining the plasma in the process volume for a residence time between about 10 seconds and about 200 seconds
Data Source
AI summary
Embodiments of the present disclosure generally relate to apparatus and methods for reducing substrate backside damage during semiconductor device processing. In one implementation, a method of chucking a substrate in a substrate process chamber includes exposing the substrate to a plasma preheat treatment prior to applying a chucking voltage to a substrate support. In one implementation, a substrate support is provided and includes a body having an electrode and thermal control device disposed therein. A plurality of substrate supporting features are formed on an upper surface of the body, each of the substrate supporting features having a substrate supporting surface and a rounded edge.