Electrostatic Chuck Adhesive-Free Spray Coating Design
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Solution Overview
Problem
Conventional electrostatic chucks face issues with low thermal conductivity due to adhesives, plasma exposure, and limited design freedom due to thick wiring configurations and thermal expansion coefficient differences, which affect temperature control and structural integrity during semiconductor processing.
Innovation Solution
An electrostatic chuck design that eliminates adhesives by using spray-coated insulating layers, thermally sprayed electrodes, and conductive paste-formed heaters, allowing for lower volume resistivity and increased design flexibility, with a manufacturing method involving screen printing, ink-jet, or dispenser methods for precise heater and electrode formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is used to bond sintered member to metallic substrate, then bonding is achieved, but thermal conductivity decreases and response during temperature descending becomes extremely low
Solution Approach 1:
The invention removes the adhesive layer from the structure by directly bonding the sintered ceramic member to the metallic substrate through sintering process. This extraction of the adhesive component eliminates the thermal conductivity barrier while maintaining bonding strength through direct ceramic-metal sintering bonds.
Solution Approach 2:
The invention creates a composite structure where the sintered ceramic member and metallic substrate are directly bonded without adhesive, forming a integrated composite component. This direct bonding approach maintains the thermal conductivity pathway from the ceramic through to the metal substrate, solving the thermal insulation problem caused by adhesive layers.
2Reliability
If heater wiring configuration is made thicker and wider to decrease resistivity, then volume resistivity decreases, but ceramic layer becomes thicker and risk of breakage or peeling-off increases
Solution Approach 1:
The invention changes the electrical conductivity parameter by using sintered ceramic materials with inherently lower volume resistivity compared to conventionally sprayed ceramic coatings. This material parameter change allows for thinner wiring configurations that maintain electrical conductivity without compromising structural integrity or requiring excessive ceramic thickness.
3Reliability
If wiring configuration is made wider to decrease resistivity, then electrical conductivity improves, but space for forming cooling gas hole or pusher pin hole is restricted
Solution Approach 1:
The invention utilizes sintered ceramic materials with improved electrical conductivity parameters, allowing for more flexible wiring design. The lower volume resistivity of the sintered material enables thinner and more efficiently routed wiring paths that maintain electrical performance while preserving design freedom for cooling gas holes and pusher pin holes.
4Ease of manufacture
If adhesive is used for bonding, then assembly is simplified, but adhesive is consumed by plasma exposure and thermal conductivity is lost
Solution Approach 1:
The invention extracts and removes the adhesive component from the assembly, replacing it with direct sintered bonds between the ceramic member and metallic substrate. This eliminates the adhesive consumption issue during plasma exposure and maintains continuous thermal conductivity pathways throughout the structure.
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 enhances temperature control accuracy, increases design freedom, and prevents structural issues like cracking or peeling, while maintaining high thermal conductivity and plasma resistance.
Implementation Method 1
an insulating layer of a spray coating which is formed on a surface at a wafer holding side of the substrate part
Implementation Method 2
an electrode part which is formed by thermal spraying a spray material or applying a conductive paste on a surface at the wafer holding side of one or more insulating layers
Implementation Method 3
a heater part of an electric conductor which is formed by applying a conductive paste on a surface at the wafer holding side of one or more insulating layers
Implementation Method 4
a wafer is adsorbed and held through coulomb force generated by applying DC voltage to the electrode
Data Source
AI summary
An electrostatic chuck and a manufacturing method are disclosed in which drawbacks of using an adhesive are not existent and a freedom degree of design is high. The electrostatic chuck includes a substrate part constituting a main chuck body, a first insulating layer of a spray coating formed to the surface of the substrate part, a heater part of an electric conductor formed by applying a conductive paste to the surface of the first insulating layer, a second insulating layer of a spray coating formed to the surface of the first insulating layer so as to cover the heater part, an electrode part formed by thermal spraying to the surface of the second insulating layer and a dielectric layer of a spray coating formed to the surface of the second layer so as to cover the electrode part and lowers a volume resistivity without using an adhesive.