Integrated Gas and Coil Assembly for Inductively Coupled Plasma Reactors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional inductively coupled plasma reactors face challenges in achieving uniform gas delivery due to electromagnetic interference from RF coils, leading to process skews and non-uniform substrate processing, especially at smaller critical dimensions.
Innovation Solution
An integrated gas and coil assembly with a grounded isolator between inner and outer RF coils, and reciprocal gas channels in the isolator, allows for symmetric gas injection into multiple zones, minimizing electromagnetic interference and enabling independent control of plasma zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single center gas line is used to deliver feedstock gas, then gas delivery is simple and symmetric, but electromagnetic coupling from RF coils induces voltage in the metal gas line causing non-uniform substrate processing
Solution Approach 1:
The single center gas line is segmented into multiple zone-specific gas lines (inner zone gas line and outer zone gas line), each delivering gas to different radial zones of the substrate. This segmentation prevents electromagnetic coupling from affecting a single centralized gas delivery path and allows independent control of gas flow to different zones, thereby maintaining processing uniformity while managing complexity.
Solution Approach 2:
A grounded isolator is introduced as an intermediary component between the RF coils and the gas lines. This isolator acts as a shield that prevents electromagnetic coupling from the RF coils from inducing voltage in the metal gas lines, thereby eliminating the source of non-uniform substrate processing while preserving the simplicity of metal gas line construction.
2Manufacturing precision
If a round hollow metal disc is used instead of a single gas line, then electromagnetic coupling is reduced, but the metal disc shields the RF field and inhibits plasma production
Solution Approach 1:
Instead of using a large continuous metal disc that would shield the RF field, the gas delivery system is segmented into multiple thin metal gas lines (inner zone gas line and outer zone gas line). These segmented metal structures have minimal cross-sectional area, allowing RF fields to pass through effectively while still providing gas delivery and resisting electromagnetic coupling through their distributed, narrow geometry.
Solution Approach 2:
The gas delivery system transitions from a uniform large-area metal disc to localized narrow metal gas lines positioned specifically where gas delivery is needed. This localizes the metal structures to minimal necessary areas, reducing their overall electromagnetic shielding effect on the RF field while maintaining gas delivery functionality and resistance to electromagnetic coupling at critical locations.
3Device complexity
If gas is injected only at the center of the reactor, then the system is simple, but process skew and non-uniformity increase at smaller critical dimensions
Solution Approach 1:
The single center gas injection point is segmented into multiple gas injection locations distributed across different zones (inner zone and outer zone). Each zone has its own gas line and injection points, enabling independent control of gas flow to different radial regions of the substrate. This segmentation allows precise control of plasma properties across the substrate surface, maintaining critical dimension uniformity while managing system complexity.
Solution Approach 2:
The gas injection system transitions from a single-point (0D) center injection to a distributed multi-point (2D) injection pattern across the substrate surface. This dimensional expansion allows gas to be delivered to multiple zones simultaneously, enabling control of plasma uniformity across the substrate area and addressing process skew issues at smaller critical dimensions.
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 ensures uniform gas distribution and minimizes process skews, allowing for better control of plasma properties and substrate processing, particularly at smaller critical dimensions.
Implementation Method 1
inductively coupled plasma reactor
Implementation Method 2
an RF shield disposed between the first and second RF field generator wherein the RF shield extends from the lower surface and past the upper surface
Data Source
AI summary
Implementations described herein inject feedstock gases into multiple zones of an inductively coupled plasma processing reactor with minimal or no effect on process skew. In one embodiment, an integrated gas and coil assembly is provided that includes an upper surface and a lower surface, a first RF field applicator coil bounded at the upper surface and the lower surface, a second RF field applicator coil circumscribed by the first RF field applicator coil and bounded at the upper surface and the lower surface and an RF shield disposed between the first and second RF field generator wherein the RF shield extends from the lower surface and past the upper surface. The RF shield may have at least one gas channel disposed therethrough.