Induction Coil Assembly Reducing Sputtering in Reaction Chambers
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Solution Overview
Problem
In semiconductor manufacturing, existing RF induction coupled plasma (ICP) systems experience high capacitive coupling between the induction coil ends and the dielectric window, leading to sputtering pollution and affected process results due to the strong capacitive coupling causing a high-voltage sheath at the lower surface of the dielectric window.
Innovation Solution
The induction coil assembly is designed with a configuration where the vertical distances between the power input and ground ends of the induction coil and the dielectric window are increased, reducing capacitive coupling while maintaining sufficient RF magnetic field coupling strength by using a three-dimensional spiral structure with varying spiral radii and lengths of coil segments, ensuring the power input end is closer to the dielectric window and the ground end is farther, thus minimizing sputtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the induction coil ends are positioned closer to the dielectric window to improve RF magnetic field coupling, then the plasma ignition is improved, but the capacitive coupling increases causing sputtering pollution
Solution Approach 1:
The patent transitions from a planar coil configuration to a three-dimensional spiral coil structure. This dimensional change allows the coil to achieve both strong RF magnetic field coupling (through optimized spiral geometry and positioning) and reduced capacitive coupling (through increased vertical distance from the dielectric window), thereby resolving the contradiction between plasma ignition reliability and sputtering prevention
Solution Approach 2:
The patent applies different spatial characteristics to different parts of the coil structure. The spiral configuration creates local variations in distance from the dielectric window, with the coil body positioned at optimal distances for both magnetic field coupling and capacitive coupling reduction. This local optimization of spatial positioning resolves the contradiction between the two opposing requirements
2Object-affected harmful factors
If the vertical distance between the induction coil ends and the dielectric window is increased to reduce capacitive coupling, then sputtering is reduced, but the RF magnetic field coupling strength decreases
Solution Approach 1:
By moving from a two-dimensional planar coil to a three-dimensional spiral coil, the patent creates multiple spatial zones with different vertical distances from the dielectric window. This allows the coil to maintain adequate coupling strength through its overall three-dimensional structure while positioning specific segments at distances that minimize capacitive coupling and sputtering
Solution Approach 2:
The spiral coil structure naturally segments the coil into multiple turns and spatial zones. This segmentation allows different portions of the coil to serve different functions: some portions optimized for magnetic field coupling while others are positioned to minimize capacitive coupling, thereby resolving the contradiction between coupling strength and sputtering reduction
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 configuration effectively reduces sputtering on the dielectric window, improves process results by minimizing capacitive coupling, and ensures the normal ignition of plasma by maintaining the required RF magnetic field coupling strength.
Implementation Method 1
an RF current flowing in an induction coil may excite an RF magnetic field in space, and generate an angular electric field in the plasma by Faraday electromagnetic induction to heat electrons to generate a high-density plasma
Implementation Method 2
a dielectric window 3 at the top of the chamber and a planar coil 2 arranged above the dielectric window 3
Implementation Method 3
the power input end A and the series capacitor terminal B form a strong capacitive coupling with the ground, which may result in the formation of a high-voltage sheath at the lower surface of the dielectric window 3
Implementation Method 4
This high-voltage sheath may cause the lower surface of the dielectric window 3 to be sputtered, which generates sputter pollution and affects process results
Data Source
AI summary
The present disclosure provides an induction coil assembly and a reaction chamber. The induction coil assembly includes an induction coil arranged over a dielectric window of the reaction chamber. Two ends of the induction coil include a power input end and a ground end, respectively. A vertical spacing between the two ends of the induction coil and the dielectric window is greater than a vertical spacing between a portion between the two ends of the induction coil and the dielectric window. The induction coil and the reaction chamber provided by the present disclosure may reduce the capacitive coupling of the two ends of the induction coil by ensuring that the coupling strength of an RF magnetic field satisfies the requirement to reduce sputtering on the dielectric window and improve process results.