Non-Contact ESC Charge Scanning for In-Situ Wafer ESD Control
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Solution Overview
Problem
In the semiconductor manufacturing industry, there is a challenge with charge accumulation on electrostatic chucks (ESCs) affecting the stability of semiconductor wafers and increasing issues with electrostatic discharge (ESD) due to the reduction of line widths, necessitating improved electrostatic charge control and measurement techniques.
Innovation Solution
An electrostatic measurement system with a non-contact probe and support structure that allows for automated scanning of ESCs and other targets, enabling precise measurement of electrostatic charges without disrupting the wafer's position, using a controller and user interface for pre-programmed patterns and manual adjustments, and incorporating a probe maneuvering mechanism for x-y and z-axis movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ESC charging methods are used, then wafer grip force is achieved, but charge accumulation occurs affecting placement stability
Solution Approach 1:
The patent replaces contact-based measurement methods with a non-contact electrostatic probe system. The probe measures surface charge density through electrostatic field interaction without physical contact, eliminating mechanical interference while monitoring charge accumulation that affects wafer placement stability
Solution Approach 2:
The electrostatic probe acts as an intermediary between the charged ESC surface and the measurement system. It detects charge accumulation through field interaction, allowing monitoring of the harmful charge buildup without directly contacting or disrupting the ESC-wafer system
2Reliability
If ESD detection and analysis are performed, then electrostatic control is improved, but processing time increases
Solution Approach 1:
The measurement system enables continuous or frequent monitoring of electrostatic charges on ESCs and wafers during processing operations. The rapid non-contact measurement capability allows charge detection to be performed continuously without interrupting the manufacturing flow, maintaining electrostatic control while minimizing time loss
Solution Approach 2:
The system provides self-service electrostatic monitoring where the measurement process itself does not require external intervention or complex setup. The automated probe system performs measurements independently, reducing operational overhead and time expenditure while maintaining continuous electrostatic control
3Measurement precision
If wafer inspection is performed, then charge detection accuracy is improved, but measurement speed decreases
Solution Approach 1:
The patent employs non-contact electrostatic field measurement instead of mechanical scanning or contact-based detection. This allows rapid measurement of charge distribution across the wafer surface without physical contact, achieving both high measurement precision for charge detection and high productivity through fast scanning capabilities
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
Enables rapid and precise measurement of electrostatic charges on ESCs and wafers, reducing processing delays and improving ESD control, allowing for in-situ measurements without removing the target from its working environment, and generating electrostatic charge maps efficiently.
Implementation Method 1
surface charge density measurements may be performed by an electrostatic probe without physical contact with a target surface
Implementation Method 2
The measurement of the surface charge on the ESC using a specifically designed system with an electrostatic probe may be an approach for detecting such charge accumulation
Data Source
AI summary
The present disclosure is directed to an electrostatic charge measurement tool and dedicated system having a probe configured to scan the surface of a target, and methods for taking the electrostatic charge measurements. In an aspect, the probe is a non-contact electrostatic probe that may be moveable across the surface of the target and be adjustable in its height from the surface of the target. In another aspect, the target is an electrostatic chuck or semiconductor wafer. In a further aspect, the electrostatic charge measurement system may perform insitu measurement of targets without removing them from their working environment.