Electrostatic Chuck Joining Layer for Thermal Stress and Heat Transfer
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Solution Overview
Problem
Existing electrostatic chucks face challenges in managing thermal stress on dielectric substrates during semiconductor processing, where temperature changes between the dielectric substrate and the base plate induce significant thermal stress, potentially damaging the substrate, and the selection of a joining layer material is critical to balance thermal stress reduction with heat-transfer performance.
Innovation Solution
The electrostatic chuck incorporates a joining layer with a thickness (T) and Young's modulus (E) relationship expressed as E≤0.04×T−0.04, utilizing a silicone adhesive to minimize thermal stress, and features a through hole with a diameter ≤0.2 mm to prevent dielectric breakdown, ensuring the joining layer's thickness is ≤100 μm to maintain effective heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the joining layer is made thicker, then thermal stress on the dielectric substrate is reduced, but heat-transfer performance deteriorates
Solution Approach 1:
The patent applies parameter changes by establishing a specific mathematical relationship between the thickness and Young's modulus of the joining layer (E≤0.04×T−0.04). This allows simultaneous optimization of both thermal stress reduction and heat-transfer performance by adjusting these parameters within defined ranges, rather than simply increasing thickness alone.
Solution Approach 2:
The patent employs composite material selection by specifying that the joining layer must have both appropriate thickness and Young's modulus characteristics, potentially using materials like silicone adhesives that can achieve the required mechanical properties while maintaining thermal conductivity for effective heat transfer.
2Stress or pressure
If the Young's modulus of the joining layer is reduced, then thermal stress on the dielectric substrate is reduced, but heat-transfer performance deteriorates
Solution Approach 1:
The patent applies parameter changes by establishing a specific mathematical relationship between the thickness and Young's modulus of the joining layer (E≤0.04×T−0.04). This allows simultaneous optimization of both thermal stress reduction and heat-transfer performance by adjusting these parameters within defined ranges, rather than simply increasing thickness alone.
3Reliability
If the through hole diameter is reduced to prevent dielectric breakdown, then electrical insulation is improved, but thermal stress concentration increases
Solution Approach 1:
The patent applies parameter changes by specifying that the through hole diameter should be 0.2 mm or smaller. This parameter optimization balances electrical insulation requirements with thermal stress management, preventing dielectric breakdown while controlling stress concentration through appropriate hole sizing.
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 thermal stress on the dielectric substrate, preventing damage while maintaining necessary heat-transfer performance, even with a thinner joining layer and smaller through hole diameter, ensuring the substrate is securely held and processed without thermal damage.
Implementation Method 1
A large thermal stress is applied to the dielectric substrate due to the temperature change in respective sections, a temperature difference between the dielectric substrate and the base plate
Implementation Method 2
the Young's modulus of the joining layer at −100° C. is E (MPa), a condition expressed as E≤0.04×T−0.04 is satisfied
Implementation Method 3
When voltage is applied to the attracting electrode, an electrostatic force is generated and a substrate placed on the dielectric substrate is attracted and held
Implementation Method 4
since a low-temperature refrigerant is supplied to the base plate, a temperature of the base plate may drop to −60° C. or to an even lower temperature than −60° C.
Data Source
AI summary
An electrostatic chuck 10 includes: a dielectric substrate 100; a base plate 200 formed of a metal material; and a joining layer 300 which is provided between the dielectric substrate 100 and the base plate 200. When a thickness of the joining layer 300 is T (μm) and a Young's modulus of the joining layer 300 at −100° C. is E (MPa), a condition expressed as E≤0.04×T−0.04 is satisfied.