Edge Ring Bias and Temperature Control for Etch Edge Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Plasma-assisted etching processes in semiconductor manufacturing result in undesirable processing result variation at the edge of the substrate due to electrical and thermal discontinuities between the substrate and the edge ring, leading to non-uniformity in etched profiles and affecting device yield.
Innovation Solution
A substrate support assembly with independent biasing and temperature control of an edge ring and substrate support, using dielectric materials and embedded electrodes, allows for fine tuning of plasma sheath shape and reactive species concentration near the substrate edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an edge ring is used to protect the substrate support from plasma erosion, then the substrate support is protected, but electrical and thermal discontinuities cause non-uniform processing results at the substrate edge
Solution Approach 1:
A biasing ring made of dielectric material is introduced as an intermediary component between the substrate support and the edge ring. This biasing ring serves as a mediator that provides both thermal isolation and electrical coupling capabilities, allowing independent biasing of the edge ring to control plasma sheath shape and eliminate processing non-uniformities while maintaining the protective function of the edge ring
Solution Approach 2:
The patent applies parameter changes by independently controlling the electrical bias voltage applied to the edge ring through the embedded biasing electrode. By adjusting the bias voltage parameter, the plasma sheath shape and reactive species concentration at the substrate edge can be controlled to achieve uniform processing results while maintaining the edge ring's protective function
2Stability of the object's composition
If the edge ring is thermally coupled to the substrate support, then structural stability is improved, but thermal discontinuities cause processing variation at the substrate edge
Solution Approach 1:
The biasing ring is designed with localized thermal properties - it provides thermal isolation at the interface between the substrate support and edge ring where discontinuity causes problems, while allowing controlled thermal coupling in other regions. This local differentiation of thermal quality enables simultaneous achievement of structural stability and processing uniformity
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
Enhances processing result uniformity by controlling plasma sheath shape and reactive species concentration, reducing edge-to-center non-uniformities and improving device yield.
Implementation Method 1
a first base plate and a second base plate circumscribing the first base plate. The first and second base plates each have one or more respective first and second cooling channels disposed therein
Implementation Method 2
cooling channels disposed therein
Implementation Method 3
The substrate support and the biasing ring are each formed of a dielectric material. The substrate support assembly further includes an edge ring biasing electrode embedded in the dielectric material of the biasing ring
Implementation Method 4
flowing a processing gas into the processing volume, igniting and maintaining a plasma of the processing gas
Implementation Method 5
Ions from the plasma are then accelerated towards the substrate, and openings formed in a mask layer disposed thereon to etch openings corresponding to the mask layer openings in the material layer disposed beneath the mask surface
Implementation Method 6
an edge ring biasing electrode embedded in the dielectric material of the biasing ring and an edge ring disposed on the biasing ring
Data Source
AI summary
Embodiments described herein provide methods and apparatus used to control a processing result profile proximate to a circumferential edge of a substrate during the plasma-assisted processing thereof. In one embodiment, a substrate support assembly features a first base plate and a second base plate circumscribing the first base plate. The first and second base plates each have one or more respective first and second cooling disposed therein. The substrate support assembly further features a substrate support disposed on and thermally coupled to the first base plate, and a biasing ring disposed on and thermally coupled to the second base plate. Here, the substrate support and the biasing ring are each formed of a dielectric material. The substrate support assembly further includes an edge ring biasing electrode embedded in the dielectric material of the biasing ring and an edge ring disposed on the biasing ring.