Conductive Chuck for Wafer Static Charge Dissipation
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Solution Overview
Problem
Semiconductor wafers experience unwanted static charge buildup during processing, even in the absence of physical contact with the chuck, due to electrostatic induction from the insulating chuck cover, which can lead to contamination and damage.
Innovation Solution
The chuck is designed with an outer surface and cover made of electrically conductive material, including conductive pathways using helical springs and conductive strips to ground, ensuring that the wafer is not in contact with the chuck body and providing a conductive path from the pin assemblies to ground, while the chuck cover is made of conductive material to prevent static charge accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the chuck cover is made of insulating material, then the wafer can be held without direct contact, but static charge buildup occurs on the wafer surface
Solution Approach 1:
The patent introduces an electrically conductive layer as an intermediary between the insulating chuck cover and the wafer. This conductive layer acts as a mediator that prevents static charge buildup on the wafer surface while maintaining the non-contact holding capability provided by the insulating cover structure.
Solution Approach 2:
The chuck is designed with a composite structure combining insulating material (chuck cover) and conductive material (conductive layer). This composite design allows the insulating portion to provide non-contact support while the conductive portion prevents static charge accumulation, resolving the contradiction between these two requirements.
2Reliability
If conductive pins are used to provide a conductive path to ground, then static charge can be dissipated, but physical contact between wafer and chuck is required
Solution Approach 1:
The conductive layer serves as an intermediary that enables static charge dissipation without requiring direct physical contact between the wafer and the conductive pins. The conductive layer extends the conductive path to the wafer surface while maintaining the non-contact holding advantage.
3Reliability
If the chuck body is made entirely of conductive material, then static charge can be grounded, but the wafer may come into direct contact with the conductive surface
Solution Approach 1:
The chuck is designed as a composite structure with an insulating outer cover and an inner conductive body. The insulating cover prevents direct contact between the wafer and the conductive body, while the conductive body provides the grounding path for static charge dissipation through its connection to ground.
Solution Approach 2:
The patent separates the functions of contact prevention and charge dissipation into different spatial dimensions. The insulating cover operates at the outer surface dimension to prevent contact, while the conductive body operates at the internal structure dimension to provide grounding, allowing both functions to coexist without interference.
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 solution effectively prevents static charge buildup on the wafer by grounding the conductive pathways, reducing the risk of electrostatic discharge and contamination, even when the wafer is not in direct contact with the chuck.
Implementation Method 1
The outer surface comprises a first electrically conductive material and the chuck body further comprises a first conductive pathway for grounding the first conductive material
Implementation Method 2
the first conductive pathway comprises at least one conductive helical spring contacting at one end a conductive element mounted on the cover and contacting at another end a conductive element mounted on the chuck base body
Implementation Method 3
Semiconductor wafers experience unwanted static charge buildup during processing, even in the absence of physical contact with the chuck, due to electrostatic induction from the insulating chuck cover
Data Source
AI summary
Apparatus for processing wafer-shaped articles comprises a chuck adapted to hold a wafer-shaped article of a predetermined diameter during a processing operation to be performed on the wafer-shaped article. The chuck comprises a chuck body having an outer surface that faces a wafer-shaped article when positioned on the chuck. The outer surface comprises a first electrically conductive material and the chuck body further comprises a first conductive pathway between the first conductive material and ground.