Showerhead Electrode Interface with Conductive Gasket and Particle Seal
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Solution Overview
Problem
In semiconductor processing, plasma etching chambers face challenges with component durability and cleanliness due to exposure to plasma, etchant gases, and thermal cycling, requiring materials that can withstand multiple wafer cycles while minimizing particle generation and maintaining functionality.
Innovation Solution
A showerhead electrode assembly with a thermally and electrically conductive gasket interface, bounded by a particle mitigating seal, enhances thermal conduction and electrical conductivity between the thermal control plate and the showerhead electrode, reducing galling and particle generation, and maintaining consistent temperature across the electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional showerhead electrode assemblies are used in plasma processing chambers, then components can be mounted and operated, but thermal non-uniformity develops and galling occurs between mating surfaces due to thermal cycling
Solution Approach 1:
The showerhead electrode assembly is divided into multiple segments including a showerhead electrode, backing plate, and thermal control plate that can be independently attached and removed. This segmentation allows each component to be optimized for its specific function while maintaining overall thermal uniformity and preventing galling at interfaces.
Solution Approach 2:
A particle mitigating seal is installed between the thermal control plate and backing plate before thermal cycling begins. This seal prevents direct metal-to-metal contact that would cause galling during thermal expansion and contraction, cushioning the interfaces against harmful mechanical stresses before they occur.
2Productivity
If components are exposed to plasma and etchant gases for multiple wafer cycles, then productivity increases, but particle generation occurs and cleanliness deteriorates
Solution Approach 1:
The particle mitigating seal extracts and contains particles at the interface between the thermal control plate and backing plate, preventing them from contaminating the plasma processing chamber. This allows the assembly to withstand multiple wafer cycles without generating harmful particles that would affect wafer cleanliness.
Solution Approach 2:
The assembly uses composite construction with a thermally conductive gasket material between the thermal control plate and backing plate. This composite structure provides both thermal uniformity across the showerhead electrode and particle mitigation, enabling sustained productivity without contamination.
3Use of energy by moving object
If thermal control is implemented through direct contact between plates, then heat transfer is efficient, but galling occurs between mating surfaces
Solution Approach 1:
A thermally conductive gasket serves as an intermediary between the thermal control plate and backing plate. This gasket maintains efficient thermal conduction while preventing direct metal-to-metal contact that would cause galling during thermal cycling, thus resolving the contradiction between heat transfer efficiency and surface protection.
Solution Approach 2:
The interface between plates is modified by introducing a gasket material that changes the thermal and mechanical parameters of the contact region. This allows maintained thermal conductivity while reducing mechanical adhesion and friction that lead to galling, enabling efficient heat transfer without surface degradation.
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 effectively reduces temperature non-uniformity, minimizes particle generation, and extends the lifespan of components by enhancing thermal transfer and preventing galling, leading to improved process yields and cleanliness in semiconductor processing.
Implementation Method 1
enhanced thermal conduction through the thermally and electrically conductive gasket portion of the interface members
Implementation Method 2
the interface member comprises a thermally and electrically conductive gasket portion
Implementation Method 3
a particle mitigating seal portion bounded on a periphery by a particle mitigating seal portion
Implementation Method 4
etching a semiconductor substrate in the plasma etching chamber by applying RF power to the showerhead electrode and energizing the process gas into a plasma state
Implementation Method 5
the temperature of the showerhead electrode is controlled by the thermal control plate via enhanced thermal conduction
Data Source
AI summary
Showerhead electrode assemblies are disclosed, which include a showerhead electrode adapted to be mounted in an interior of a vacuum chamber; an optional backing plate attached to the showerhead electrode; a thermal control plate attached to the backing plate or to the showerhead electrode at multiple contact regions across the backing plate; and at least one interface member separating the backing plate and the thermal control plate, or the thermal control plate and showerhead electrode, at the contact regions, the interface member having a thermally and electrically conductive gasket portion and a particle mitigating seal portion. Methods of processing semiconductor substrates using the showerhead electrode assemblies are also disclosed.