Electrostatic Clamping Patterns for Insulating Optical Substrates
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Solution Overview
Problem
Existing electrostatic clamping techniques are ineffective for electrically insulating substrates such as glass or amorphous silicon wafers, as they lack a conductive surface for electrostatic attraction.
Innovation Solution
The method involves applying electrically conductive material in the form of rings, lines, or grids on the surface of electrically insulating substrates, allowing for electrostatic clamping to an electrostatic chuck during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrostatic clamping is used on electrically insulating substrates, then the substrate can be held during processing, but the insulating substrate cannot be effectively clamped because it lacks a conductive surface for electrostatic attraction
Solution Approach 1:
The conductive layer is segmented into discrete patterns (rings, lines, or grids) rather than a continuous coating. These segmented conductive elements are strategically positioned on the insulating substrate to provide electrostatic attraction points while maintaining the overall insulating properties of the substrate.
Solution Approach 2:
The substrate is transformed from uniformly insulating to having localized conductive regions. The conductive material is applied only in specific areas (where clamping is needed) rather than covering the entire substrate, creating local conductive quality on an otherwise insulating surface.
2Reliability
If conductive material is applied to the insulating substrate, then electrostatic clamping becomes effective, but the substrate structure becomes more complex
Solution Approach 1:
The conductive material pattern serves multiple functions simultaneously: it provides the necessary electrostatic clamping surface, defines optical apertures for laser processing, creates field stops to control plasma distribution, and can form eye-safety circuits. This multi-functionality reduces overall system complexity despite adding conductive material.
Solution Approach 2:
The conductive clamping pattern is merged with existing optical and processing features on the substrate. The same conductive rings, lines, or grids that enable electrostatic clamping also serve as optical apertures, field stops, or eye-safety circuits, combining multiple functions into a single structural element.
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 approach enables effective electrostatic clamping and processing of electrically insulating substrates, facilitating techniques like lithography, ion implantation, and film deposition.
Implementation Method 1
A substrate and an electrostatic chuck are attracted to each other via an electrostatic force
Data Source
AI summary
In an example implementation, an apparatus includes an electrically insulating substrate, optical elements in or on the substrate, and electrically conductive material on a surface of the substrate and laterally surrounding at least some of the optical elements. The electrically conductive material facilitates clamping of the electrically insulating substrate to an electrostatic chuck.