Electrostatic Chuck Electrode Thickness and Inductor Filtering
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Solution Overview
Problem
Existing electrostatic chucks used in high temperature/high power Physical Vapor Deposition (PVD) processes face issues such as overheating, substrate backside arcing, and process variations due to high RF current and unshielded wiring.
Innovation Solution
The electrostatic chuck design includes thicker embedded electrodes to reduce current density, a high temperature inductor proximate to the DC voltage sensing circuit to filter high frequency currents, and high temperature coaxial cables for repeatable and efficient RF applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If existing electrostatic chucks are used for high power PVD processes, then high temperature and high power operation is achieved, but overheating occurs when RF current in the electrodes gets too high
Solution Approach 1:
The patent changes the physical parameter of electrode thickness from conventional thin electrodes to thick electrodes (with thickness of about 3 to about 5 times the calculated skin depth). This parameter change allows the electrodes to handle high RF current densities without overheating, as the increased thickness provides greater thermal mass and reduced current density, enabling high power operation while preventing overheating.
2Use of energy by moving object
If high frequency RF power is used, then RF receiver efficiency is improved, but substrate backside arcing occurs to the DC voltage sensing circuit
Solution Approach 1:
The patent introduces an inductor as an intermediary component between the substrate and the DC voltage sensing circuit (center-tap circuit). This inductor acts as a mediator that blocks high frequency RF currents from reaching the sensing circuit while allowing DC voltage measurement to proceed. The inductor effectively decouples the harmful RF arcing from the sensitive DC sensing circuit, enabling high frequency RF operation without substrate backside arcing.
3Device complexity
If unshielded wiring is used to provide power to heaters and electrodes, then device complexity is reduced, but process variations occur
Solution Approach 1:
The patent employs coaxial cables with shielding as a protective shell structure for RF power transmission. The coaxial cable's outer conductor acts as a shield that contains the RF electromagnetic fields, preventing interference with other chamber components and ensuring stable power delivery. This shielding approach eliminates process variations caused by unshielded wiring while maintaining a relatively simple implementation through standard coaxial cable components.
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 design prevents overheating, reduces backside arcing, and ensures repeatable performance and higher efficiency in high temperature/high power RF applications by managing current flow and impedance.
Implementation Method 1
an inductor disposed in the body and proximate the support surface of the body, wherein the inductor is electrically coupled to DC voltage sensing circuit, and wherein the inductor is configured to filter high frequency current flow in order to accurately measure DC potential on the substrate
Implementation Method 2
Existing electrostatic chucks (ESC) currently used for high temperature/high power Physical Vapor Deposition (PVD) applications have limitations when used with RF power. Those limitations may include, but are not limited to, 1) ESC overheating when the RF current in the electrodes gets too high during high power processes
Implementation Method 3
a body having a support surface coupled to the second surface of the puck to support the puck, wherein a thickness of each of the one or more chucking electrodes is about 3 to about 5 times a calculated skin depth of the one or more chucking electrodes
Data Source
AI summary
An electrostatic chuck includes a puck having a support surface to support a substrate when disposed thereon and an opposing second surface, wherein one or more chucking electrodes are embedded in the puck, a body having a support surface coupled to the second surface of the puck to support the puck, a DC voltage sensing circuit disposed on support surface of the puck, and an inductor disposed in the body and proximate the support surface of the body, wherein the inductor is electrically coupled to DC voltage sensing circuit, and wherein the inductor is configured to filter high frequency current flow in order to accurately measure DC potential on the substrate.