Diffusion Bonded Electrostatic Clamp for Wafer Stability
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Solution Overview
Problem
Conventional electrostatic clamps for holding semiconductor wafers face challenges in achieving high geometric and thermal stability, precision, and durability due to limitations in manufacturing methods and materials, such as adhesive bonding, anodic bonding, and sintering, which result in limited accuracy, wear resistance, and increased production costs.
Innovation Solution
An electrostatic holding apparatus with a multilayer base body and electrode device using a diffusion bond connection between electrically insulating base body plates and conductive electrode layers, allowing for high electrical conductivity and thermal stability, and enabling precise and durable electrostatic clamping of semiconductor wafers at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive bonding is used to join base body plates, then the manufacturing process is simple, but the geometric stability and precision are limited
Solution Approach 1:
The patent replaces mechanical adhesive bonding with diffusion bonding, a process that uses thermal and pressure fields to create atomic-level connections between base body plates. This substitution eliminates the need for adhesives and achieves superior geometric stability through direct material diffusion at the interface, resolving the contradiction between manufacturing simplicity and geometric precision.
Solution Approach 2:
The patent employs diffusion bonding parameters (temperature, pressure, time) to transform the joining process. By controlling these parameters, the base body plates achieve intimate contact and atomic diffusion at the interface, creating a joint with superior geometric stability compared to adhesive bonding, while maintaining a relatively simple process flow.
2Ease of manufacture
If conventional bonding methods are used, then production costs are reduced, but thermal stability above 350°C is not achieved
Solution Approach 1:
The patent utilizes diffusion bonding parameters (temperature range, pressure, holding time) to create joints that maintain integrity at elevated temperatures. The diffusion-bonded interface exhibits superior thermal stability above 350°C compared to adhesive bonding, while the process remains cost-effective by eliminating adhesive materials and simplifying the bonding procedure.
Solution Approach 2:
The patent creates a composite structure through diffusion bonding where the joined base body plates form an integrated thermally stable assembly. The diffusion-bonded interface acts as a seamless transition zone that maintains thermal performance, enabling the electrostatic clamp to operate stably at high temperatures without the thermal limitations of adhesive bonding.
3Temperature
If multi-layer base body plates are used for thermal stability, then thermal conductivity improves, but manufacturing complexity increases
Solution Approach 1:
The patent divides the base body into multiple plates with different material properties optimized for specific functions (e.g., thermal conductivity, mechanical strength, electrostatic performance). Each plate can be manufactured and pre-characterized separately, then joined via diffusion bonding to create the complete multi-functional base body, balancing thermal performance with manageable manufacturing complexity.
4Manufacturing precision
If high positioning accuracy is achieved through precision manufacturing, then wafer positioning improves, but production costs increase
Solution Approach 1:
The patent replaces complex precision mechanical assembly with diffusion bonding, which inherently creates precise, repeatable joints through atomic-level material diffusion. This substitution achieves high positioning accuracy for wafer handling without the escalating costs associated with ultra-precision mechanical manufacturing and assembly, as diffusion bonding provides consistent geometric stability at scale.
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 provides a geometrically, mechanically, and thermally stable electrostatic holding apparatus that maintains high precision and durability, simplifying manufacturing and reducing production costs while tolerating elevated temperatures, thus overcoming the limitations of conventional techniques.
Implementation Method 1
The base body comprises at least two electrically insulating base body plates, which are connected to one another over a surface by a joint connection, in particular by a diffusion bond connection
Implementation Method 2
When an electrical voltage is applied to the electrode layers, a component lying on the base body is attracted and held in position due to Coulomb's law
Data Source
AI summary
A holding apparatus, which is adapted for electrostatically holding a component, in particular a wafer, comprises an electrically insulating base body, which comprises a first pair of base body plates, which are connected to one another in a planar manner via a joint connection, and an electrode device with at least one electrode layer, which is arranged to generate an electrostatic holding force and extends parallel to the extension of the base body plates along the joining connection, wherein the joining connection comprises a diffusion bond connection, wherein the at least one electrode layer is connected in a planar manner to the respectively adjacent base body plate, and the at least one electrode layer has a contact section, which is arranged for electrically contacting the at least one electrode layer. Methods for manufacturing the holding apparatus are also described.