Toroidal Plasma Source Azimuthal Apertures for Wafer Uniformity
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Solution Overview
Problem
As semiconductor wafer sizes increase and feature sizes decrease, achieving spatially uniform plasma processing becomes increasingly challenging, requiring significant improvements in processing uniformity to effectively etch, clean, or deposit materials on wafers.
Innovation Solution
The design of a toroidal plasma source with a plasma generation block and magnetic elements that induce an electric field to generate plasma, distributing plasma products through multiple azimuthally distributed output apertures, ensuring a circular and spatially uniform pattern for plasma processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wafer sizes increase and feature sizes decrease, then more integrated circuits can be harvested per wafer, but processing uniformity deteriorates
Solution Approach 1:
The plasma source is divided into multiple independent plasma generation blocks, each with its own plasma cavity and output apertures. This segmentation allows each block to independently generate and distribute plasma products, improving overall uniformity across the large wafer surface while maintaining high productivity
Solution Approach 2:
Each plasma generation block is designed with specific local characteristics including azimuthally distributed output apertures and strategically positioned magnetic elements. This local quality optimization ensures uniform plasma distribution from each block, which collectively achieves processing uniformity across the entire large wafer surface
2Ease of operation
If plasma is generated using conventional sources, then plasma processing can be performed, but recombination and wall effects increase
Solution Approach 1:
The plasma generation blocks are positioned in a three-dimensional configuration above the wafer, with plasma products distributed through vertical and radial pathways. This dimensional arrangement minimizes plasma travel distance and reduces interactions with chamber walls, thereby decreasing recombination and wall effects while maintaining plasma processing capability
Solution Approach 2:
The design extracts plasma products directly from the plasma cavity through multiple output apertures in the plasma generation block, delivering them directly to the wafer surface. This extraction approach minimizes plasma residence time in the chamber, reducing recombination and wall interactions
3Ease of operation
If conventional plasma sources are used, then plasma can be generated, but sputtering damage occurs
Solution Approach 1:
The plasma generation blocks operate at optimized pressure and power parameters that reduce ion energy while maintaining plasma density. This parameter optimization allows plasma generation to proceed effectively while minimizing ion-induced sputtering damage to the wafer and chamber components
4Device complexity
If plasma products are distributed through single or few apertures, then device complexity is reduced, but spatial uniformity deteriorates
Solution Approach 1:
Each plasma generation block is segmented into multiple plasma cavities, and each cavity has multiple output apertures distributed azimuthally around the toroidal axis. This segmentation creates numerous plasma product delivery points that collectively provide spatially uniform coverage across the wafer surface
Solution Approach 2:
The plasma cavities are designed with toroidal geometry, and output apertures are distributed azimuthally around the toroidal axis. This curved, symmetric arrangement ensures uniform plasma product distribution in all radial directions, achieving spatial uniformity without requiring an excessive number of apertures
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 approach minimizes recombination and wall effects, reduces sputtering damage, and enables high-pressure plasma generation with uniform plasma distribution across a wide area, enhancing processing uniformity and equipment longevity.
Implementation Method 1
A magnetic element at least partially surrounds the plasma generation block at one azimuthal location with respect to the toroidal axis, such that a magnetic flux within the magnetic element induces a corresponding electric field into the plasma cavity to generate a plasma from one or more source gases
Implementation Method 2
The plasma generation block supplies the plasma products through a plurality of output apertures defined by the plasma generation block on the first axial side
Data Source
AI summary
An apparatus for supplying plasma products includes a plasma generation block that defines a toroidal plasma cavity therein. The plasma cavity is substantially symmetric about a toroidal axis, and the toroidal axis defines a first and second axial side of the plasma generation block. A magnetic element at least partially surrounds the plasma generation block at one azimuthal location with respect to the toroidal axis, such that a magnetic flux within the magnetic element induces a corresponding electric field into the plasma cavity to generate a plasma from one or more source gases, the plasma forming plasma products. The plasma generation block supplies the plasma products through a plurality of output apertures defined by the plasma generation block on the first axial side.