Polyceramic E-Chuck Design for Reduced Capacitance and Arcing
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Solution Overview
Problem
Existing electrostatic chucks in semiconductor manufacturing have prolonged charging and discharging periods, electrical bridging issues, and arcing problems, which hinder faster throughput and increase contamination risks.
Innovation Solution
A three-layer electrostatic chuck design with a top dielectric layer of high dielectric constant, an intermediate conductive layer, and a bottom polymer dielectric layer, optimized for reduced capacitance and arcing prevention, using materials like ceramic and polymer combinations with specific resistivity and dielectric constant ranges, and featuring mesa structures and anti-arc coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a metal base is used in the chuck construction, then the chuck can provide a heat sink and structural support, but electrical bridging or arcing occurs that results in leakage between electrodes and the base
Solution Approach 1:
The patent introduces a dielectric layer as an intermediary between the metal base and the electrostatic electrodes. This dielectric layer serves as a mediator that allows thermal contact with the metal heat sink while preventing electrical arcing and leakage, thus resolving the contradiction between heat dissipation and electrical isolation.
Solution Approach 2:
The chuck construction uses composite materials combining metal (for heat sinking and structural support) with dielectric materials (for electrical isolation). This composite structure enables simultaneous achievement of thermal management and electrical insulation, resolving the contradiction between heat sink capability and arcing prevention.
2Reliability
If the chuck uses conventional multilayer ceramic design, then the chuck can hold electrostatic charge, but charging and discharging periods are prolonged up to 10 seconds or longer
Solution Approach 1:
The patent changes the dielectric parameters by selecting materials with optimized dielectric constants and loss tangents. By carefully selecting dielectric materials with appropriate electrical properties, the charging and discharging time constants are reduced while maintaining sufficient electrostatic charge holding capability for wafer clamping.
Solution Approach 2:
The patent applies different dielectric materials with different properties to different regions or layers of the chuck structure. This allows optimization of charge holding in some regions while reducing charging time in others, resolving the contradiction between charge retention and charging speed.
3Use of energy by moving object
If the chuck uses lower dielectric constant materials, then the capacitive load on semiconductor tools is reduced, but the electrostatic charge holding capability may be compromised
Solution Approach 1:
The patent uses composite dielectric structures combining materials with different dielectric constants. This allows the overall chuck to have reduced capacitive load while specific layers maintain sufficient charge holding capability through higher dielectric constant materials positioned where needed.
Solution Approach 2:
The patent optimizes the dielectric parameters by selecting materials and thicknesses that achieve the desired balance between capacitive load and charge holding. By adjusting dielectric constant and layer thickness parameters, the system achieves reduced capacitive burden on tools while maintaining adequate electrostatic clamping force.
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 design reduces capacitive load, minimizes arcing, and enhances manufacturing efficiency with faster wafer clamping and release times, while maintaining electrostatic charge without significant eddy current losses, thus improving semiconductor processing.
Implementation Method 1
The chuck comprises a top dielectric layer... and a bottom dielectric layer... The chuck further comprises an intermediate layer having a resistivity of from about 1.5E-8 ohm.m to about 1 ohm.m
Implementation Method 2
The chuck further comprises an intermediate layer having a resistivity of from about 1.5E-8 ohm.m to about 1 ohm.m
Data Source
AI summary
The present invention discloses an electrostatic chuck for clamping work substrates, said chuck comprising three layers, where the dielectric constant of included non-conductive layers is selected to provide overall lower capacitance to the chuck. In the chuck assembly of the present invention, the top dielectric layer that is in contact with a substrate, such as, a wafer, has a dielectric constant that is preferably greater than about 5, with a resistivity that is preferably greater than about 1E6 ohm.m, whereas the bottom dielectric layer has a dielectric constant that is preferably less than about 5 and a resistivity that is preferably greater than about 1E10 ohm.m. The intermediate layer preferably has a conductive layer where the resistivity is less than about 1 ohm.m.