Edge Ring Bias and Temperature Control for Uniform Plasma Etching
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Solution Overview
Problem
Plasma-assisted etching processes in semiconductor manufacturing often result in undesirable processing variations at the substrate edge due to electrical and thermal discontinuities between the substrate and the edge ring, leading to non-uniform etched profiles and reduced device yield.
Innovation Solution
A substrate support assembly with independent thermal and electrical biasing of the edge ring, allowing for fine control of the plasma sheath and neutral species concentration near the substrate edge, comprising a first and second base plate with cooling channels, a substrate support, and a biasing ring with an embedded edge ring biasing electrode, enabling precise temperature and voltage control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If an edge ring is added to protect the dielectric material from erosion, then the durability of the substrate support assembly is improved, but electrical and thermal discontinuities are introduced causing processing result variation
Solution Approach 1:
The patent applies local quality by providing independent temperature control and electrical biasing specifically for the edge ring region. The edge ring is equipped with separate heating elements and cooling channels, allowing its temperature to be independently adjusted from the substrate support. Additionally, an edge ring biasing electrode provides localized electrical control. This enables the edge ring to have different thermal and electrical properties tailored to compensate for edge effects while maintaining uniform processing results across the substrate.
2Manufacturing precision
If independent temperature control of the edge ring is implemented, then processing result variation is reduced, but device complexity increases
Solution Approach 1:
The patent merges the temperature control functions by integrating heating elements and cooling channels into the existing substrate support assembly structure. The edge ring shares the same base plate and cooling channel infrastructure as the substrate support, allowing both regions to be controlled through a unified thermal management system. This integration reduces the need for separate external control systems and minimizes overall device complexity.
Solution Approach 2:
The base plate serves multiple functions: it provides structural support for both the substrate support and edge ring, contains cooling channels for thermal management of both regions, and houses heating elements for temperature control. This multi-functionality reduces the number of separate components needed and simplifies the overall assembly while enabling independent temperature control of the edge ring.
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 solution effectively tunes the plasma sheath and chemical reactions at the substrate edge, reducing processing variations and improving the uniformity of etched profiles, thereby enhancing device yield and processing precision.
Implementation Method 1
The first and second base plates each have one or more respective first and second cooling channels disposed therein
Implementation Method 2
heating a substrate support of a substrate support assembly to a first temperature, heating an edge ring circumscribing the substrate support to a second temperature
Implementation Method 3
a plasma is formed there above. Ions from the plasma are then accelerated towards the substrate
Implementation Method 4
Ions from the plasma are then accelerated towards the substrate, and openings formed in a mask layer disposed thereon to etch openings
Implementation Method 5
an edge ring biasing electrode embedded in the dielectric material of the biasing ring... biasing the edge ring using a second bias voltage
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.