Electrostatic Chuck with Planarized Resin Sheet
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Solution Overview
Problem
Conventional methods for thinning semiconductor wafers face challenges such as cracking and thickness variations, particularly when using support wafers with resin bonding, and electrostatic holding devices with surface waviness limit their applicability in micro-photolithography and grinding processes.
Innovation Solution
An electrostatic attachment chuck with a substrate and a synthetic resin sheet having a planarized and ground surface, where electrodes are disposed within the resin sheet, allowing for precise holding and easy release of semiconductor wafers, reducing thickness variations and enabling high-accuracy thinning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a support wafer with resin bonding is used to hold the semiconductor wafer, then the risk of cracking can be reduced, but thickness variations and poor flatness occur
Solution Approach 1:
The patent replaces the mechanical resin bonding system with an electrostatic holding system. The electrostatic attachment chuck uses electrostatic forces to hold the semiconductor wafer without physical contact through resin, thereby eliminating the thickness variations and flatness issues caused by resin while maintaining crack prevention through controlled electrostatic attraction.
Solution Approach 2:
The patent changes the holding mechanism from mechanical (resin bonding) to electrostatic (electric field-based). By controlling electrical parameters such as voltage applied to the electrodes, the system achieves reliable wafer holding without the physical interference that causes thickness variations, enabling both crack prevention and thickness uniformity.
2Ease of manufacture
If an electrostatic holding device with surface waviness is used, then direct joining is possible, but the device cannot be used in micro-photolithography and grinding processes
Solution Approach 1:
The patent divides the electrostatic holding device into two distinct functional parts: a substrate that provides mechanical support and a separate synthetic resin sheet that provides the electrostatic holding function. This segmentation allows the resin sheet to be independently processed to achieve high surface flatness through planarization and grinding, while the substrate maintains the electrostatic electrode structure.
Solution Approach 2:
The patent applies different properties to different parts of the device: the substrate is designed for electrostatic function with embedded electrodes, while the synthetic resin sheet is specifically engineered for surface quality with planarized and ground surfaces. This local quality differentiation enables the holding surface to meet the stringent flatness requirements for micro-photolithography and grinding processes.
3Strength
If resin bonding is used to join support wafer to semiconductor wafer, then holding strength is provided, but thickness variations occur
Solution Approach 1:
The patent replaces the resin bonding mechanical system with an electrostatic field-based holding system. The electrostatic attachment chuck generates holding force through electrical attraction between electrodes and the semiconductor wafer, eliminating the need for physical resin bonding that causes thickness variations, while maintaining adequate holding strength through controlled electrostatic forces.
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 electrostatic attachment chuck achieves reduced thickness variations, improved yield, and enhanced device performance by providing a flat, high-accuracy holding surface for semiconductor wafers, suitable for advanced microfabrication and ultra-thinning applications.
Implementation Method 1
an electrostatic holding device which holds a semiconductor wafer using an electrostatic force (Coulomb force)
Data Source
AI summary
An electrostatic attachment chuck includes: a substrate; a synthetic resin sheet joined to one main surface of the substrate; and at least a pair of electrodes disposed in the synthetic resin sheet. The synthetic resin sheet includes a planarized and ground surface serving as a surface on which a semiconductor wafer is abutted.