Electrostatic Chuck Heater Niobium Diffusion Barrier
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Solution Overview
Problem
Conventional coulomb-type electrostatic chucks with heaters have insufficient chucking and de-chucking response due to low volume resistivity in the dielectric layer and niobium diffusion into the supporting member, leading to reduced thermal uniformity and processing efficiency in semiconductor manufacturing.
Innovation Solution
An electrostatic chuck with a base composed of an alumina sintered body, a dielectric layer with low carbon content, and a niobium-based resistance heating element formed into a coil, embedded within a supporting member with controlled carbon content to prevent niobium diffusion and enhance thermal uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dielectric layer is used between the electrode and substrate holding surface, then insulation is provided, but the volume resistivity is small which results in insufficient chucking and de-chucking response
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric layer by strictly controlling carbon content to not more than 100 ppm. This parameter change increases the volume resistivity from conventional low values to above 1×10^16 Ω·cm, thereby improving both insulation performance and electrostatic response speed simultaneously
2Power
If niobium is used as the main component of the resistance heating element, then desired heating performance is achieved, but niobium diffuses into the supporting member causing resistance changes and thermal non-uniformity
Solution Approach 1:
The patent introduces carbon as an intermediary substance in the supporting member (0.03-0.25 wt%) that acts as a diffusion barrier. This intermediary layer prevents niobium atoms from migrating into the supporting member while allowing the heating element to maintain its desired heating performance through resistive heating
Solution Approach 2:
The supporting member is designed as a composite material combining alumina with controlled carbon content (0.03-0.25 wt%). This composite structure provides both mechanical support and chemical barrier functions, preventing niobium diffusion while maintaining thermal properties for uniform heating
3Ease of manufacture
If the resistance heating element is made as a thin film by screen printing, then manufacturing is simplified, but heating efficiency and thermal uniformity are reduced
Solution Approach 1:
The patent transforms the flat thin-film heating element into a three-dimensional coil structure. This curvature change enables volumetric heat generation and three-dimensional heat radiation, significantly improving heating efficiency and thermal uniformity across the substrate holding surface
Solution Approach 2:
The heating element transitions from a two-dimensional thin film to a three-dimensional coil structure. This dimensional change allows heat to be generated and distributed throughout the volume of the supporting member, achieving superior thermal uniformity and heating efficiency
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 solution improves chucking and de-chucking response, maintains desired resistance values, ensures thermal uniformity, and extends the electrostatic chuck's lifespan by preventing niobium diffusion and enhancing heating efficiency.
Implementation Method 1
a resistance heating element embedded in a lower part of the base... another part between the electrode and the lower surface of the base is formed as a supporting member
Implementation Method 2
a coulomb-type electrostatic chuck with a heater... an electrode embedded in an upper part of the base; and a dielectric layer between the electrode and an upper surface of the base
Implementation Method 3
The supporting member has a carbon content of 0.03 to 0.25 wt %. Moreover, the resistance heating element is formed into a coil and mainly composed of niobium... niobium as a main component of the resistance heating element is prevented from diffusing into the supporting member
Implementation Method 4
the resistance heating element is formed into a coil and radiates heat three-dimensionally. Accordingly, the resistance heating element can transmit heat to the substrate holding surface more efficiently
Data Source
AI summary
An electrostatic chuck with a heater including: a base which is composed of a sintered body containing alumina, an electrode disposed in an upper part of the base, and a resistance heating element embedded in a lower part of the base. The base includes a dielectric layer between the electrode and an upper surface of the base and a supporting member between the electrode and a lower surface of the base. The dielectric layer has a carbon content of not more than 100 ppm, and the supporting member has a carbon content of 0.03 to 0.25 wt %. Moreover, the resistance heating element is formed into a coil and mainly composed of niobium.