Wafer Grounding Contact Control for Stable Imaging
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Solution Overview
Problem
Current wafer grounding methods, such as penetration and electrical zapping, face challenges including damage to the backside film, contamination, and inefficiency in establishing a stable electrical connection, particularly with varying substrate types and thickened backside films, which affects imaging quality and equipment longevity.
Innovation Solution
The implementation of a system that dynamically adjusts grounding signal characteristics and contact locations using sensors and actuators, including a vibrator to improve contact and reduce contamination, and a pin-impact method for thickened films, to establish a reliable electrical connection while minimizing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If penetration method or electrical zapping is used to establish electrical connection, then electrical connection is achieved, but backside film is damaged and contamination occurs
Solution Approach 1:
A grounding pin with a flat contact surface is introduced as an intermediary between the electrical connection system and the wafer backside film. The pin establishes electrical connection through controlled contact pressure and vibration rather than penetration or high-voltage zapping, thereby avoiding damage to the backside film while maintaining reliable electrical connection.
Solution Approach 2:
Vibration is applied to the grounding pin during contact with the wafer backside film. This vibration helps to clean the contact surface, improve electrical contact quality, and establish stable connection without requiring penetration or high-voltage discharge, thus preventing backside film damage and contamination.
2Reliability
If conventional grounding methods are used, then electrical connection is established, but grounding pin lifetime is reduced due to repeated contact and wear
Solution Approach 1:
The conventional mechanical penetration method is replaced with a non-penetrating contact method. The grounding pin makes surface contact with the backside film rather than penetrating it, significantly reducing mechanical wear on the pin and extending its operational lifetime while maintaining reliable electrical connection.
3Device complexity
If fixed grounding location is used, then system is simple, but imaging quality deteriorates due to electrical potential variations
Solution Approach 1:
The grounding system is made dynamic by allowing the grounding pin to be repositioned to different locations on the wafer backside film. This dynamic adjustment capability enables optimization of electrical connection quality for different wafer types and imaging requirements, improving imaging quality without significantly increasing system complexity.
4Loss of time
If standard electrical zapping is used, then connection is established quickly, but contamination occurs and equipment longevity is reduced
Solution Approach 1:
Instead of using high-voltage electrical zapping that causes contamination, the invention uses mechanical vibration and controlled contact pressure to establish electrical connection. This approach converts the potentially harmful electrical discharge into a benign mechanical contact process, eliminating contamination while maintaining fast connection establishment.
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 enhances the success rate of wafer grounding, reduces contamination, prolongs grounding pin lifetime, and adapts to different substrate types, ensuring stable imaging and improved equipment performance.
Implementation Method 1
vibrating at least one of the grounding pin or the wafer
Implementation Method 2
establishing an electrical connection between the grounding pin and the wafer
Implementation Method 3
causing a grounding pin to penetrate through the coating on the wafer by impact
Data Source
AI summary
Systems and methods for wafer grounding and wafer grounding location adjustment are disclosed. A first method may include receiving a first value of an electric characteristic associated with the wafer being grounded by an electric signal; determining a first control parameter using at least the first value; and controlling a characteristic of the electric signal using the first control parameter and the first value. A second method for adjusting a grounding location for a wafer may include terminating an electric connection between the wafer and at least one grounding pin in contact the wafer; adjusting a relative position between the wafer and the grounding pin; and restoring the electric connection between the grounding pin and the wafer. A third method may include causing a grounding pin to penetrate through a coating on the wafer by impact; and establishing an electrical connection between the grounding pin and the wafer.