Electrostatic Chuck Surface Dielectric Layer for High-Temperature Stability
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Solution Overview
Problem
Existing electrostatic chucks face challenges in high-temperature applications due to the failure of high-temperature adhesives above 250 °C, which affects the reliability of electrostatic clamping and temperature control in semiconductor processing.
Innovation Solution
An electrostatic chuck design featuring a ceramic structural element with a surface dielectric layer comprising amorphous alumina, aluminum oxynitride, and silicon oxide or silicon oxynitride layers, which provides enhanced dielectric strength and stability up to 750 °C, enabling effective electrostatic clamping and temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-temperature adhesives are used to bond the electrode onto the ceramic body, then the electrode can be securely attached, but the adhesive fails when temperatures exceed about 250 °C
Solution Approach 1:
The patent removes the adhesive layer from the electrode bonding process entirely. Instead of using adhesive to bond the electrode to the ceramic body, the electrode is directly embedded into recesses formed in the ceramic body during the ceramic firing process, eliminating the reliability issue of adhesive failure at high temperatures
Solution Approach 2:
The patent combines the electrode attachment process with the ceramic body formation process. The electrode is embedded into the ceramic body during the same firing cycle used to sinter the ceramic, merging two separate processes (ceramic formation and electrode attachment) into one integrated process, thereby eliminating the need for separate adhesive bonding
2Strength
If a thick surface dielectric layer is used to provide adequate insulation and electrostatic clamping, then the dielectric strength is improved, but the chucking force and temperature control efficiency decrease
Solution Approach 1:
The patent employs a composite surface dielectric layer structure consisting of multiple materials with different properties. The layer includes a first dielectric material (such as aluminum oxynitride or silicon oxynitride) providing high dielectric strength, and a second dielectric material (such as silicon oxide) with different thermal and mechanical properties. This composite structure optimizes both dielectric strength and chucking force by combining the advantages of different materials
Solution Approach 2:
The patent creates different regions within the surface dielectric layer with different thicknesses and material compositions. The dielectric layer is designed with varying local properties to optimize performance: thicker regions provide insulation where needed, while thinner regions maintain electrostatic field strength for effective chucking. The composite materials are strategically positioned to provide local optimization of both dielectric strength and mechanical properties
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 enables reliable high-temperature processing of semiconductor substrates by maintaining electrostatic clamping and temperature control capabilities, even at extreme temperatures, thereby improving the performance and durability of the electrostatic chuck.
Implementation Method 1
a surface dielectric layer disposed over the at least one electrode, the surface dielectric layer activated by a voltage in the electrode to form an electric charge to electrostatically clamp a substrate to the electrostatic chuck
Implementation Method 2
The insulator layer of amorphous alumina is deposited by atomic layer deposition over the at least one electrode
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
An electrostatic chuck includes a ceramic structural element, at least one electrode disposed on the ceramic structural element, and a surface dielectric layer disposed over the at least one electrode, the surface layer activated by a voltage in the electrode to form an electric charge to electrostatically clamp a substrate to the electrostatic chuck. The surface dielectric layer comprises: (i) an insulator layer of amorphous alumina, of a thickness of less than about 5 microns, disposed over the at least one electrode; and (ii) a stack of dielectric layers disposed over the insulator layer. The stack of dielectric layers includes: (a) at least one dielectric layer including aluminum oxynitride; and (b) at least one dielectric layer including at least one of silicon oxide and silicon oxynitride.