Wafer Chuck Protrusions for Static Discharge in Semiconductor Cleaning
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Solution Overview
Problem
During semiconductor wafer cleaning, particularly after CMP and resist removal, abnormal discharge occurs due to static electricity generated in chemical solutions containing electrolytes like sulfuric acid, which can irreversibly damage the wafer, especially when insulating films are present, as existing measures such as conductive pipes and grounding fail to effectively prevent charging.
Innovation Solution
The method involves bringing the chemical solution into contact with wafer chucks prior to application, allowing static electricity to be discharged through the chucks, which are designed with protrusions and a conductive plating film for efficient discharge, preventing damage during the cleaning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical solution is supplied directly to the wafer for cleaning, then cleaning effectiveness is improved, but static electricity discharge damages the wafer
Solution Approach 1:
The chemical solution is made to contact the wafer chucks before contacting the wafer surface. The wafer chucks are equipped with conductive plating films that discharge static electricity from the chemical solution, preventing abnormal discharge when the solution reaches the wafer. This preliminary discharge action eliminates the harmful static electricity before it can damage the wafer.
Solution Approach 2:
The wafer chucks with conductive plating films serve as an intermediary between the chemical solution supply system and the wafer. This intermediary component provides a controlled path for static electricity discharge, allowing the chemical solution to be safely introduced to the wafer area without direct harmful contact between charged solution and sensitive wafer elements.
2Object-affected harmful factors
If conductive pipes and grounding are used to prevent charging, then static electricity discharge is reduced, but abnormal discharge still occurs when insulating films are present
Solution Approach 1:
Instead of attempting to ground the entire chemical solution supply system, the invention applies conductive plating films locally to specific contact points on the wafer chucks where the chemical solution first contacts the system. This localized conductive treatment at the critical interface provides effective static discharge without requiring comprehensive grounding of all supply components.
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 effectively suppresses abnormal discharge and wafer damage by ensuring static electricity is discharged before the chemical solution reaches the wafer, maintaining the integrity of semiconductor devices during cleaning.
Implementation Method 1
bringing the chemical solution into contact with wafer chucks prior to application, allowing static electricity to be discharged through the chucks
Implementation Method 2
a chemical solution (SPM) stored in a chemical solution tank is subjected to friction with inner walls of pipes to be charged on a way to be sent to a cleaning nozzle through the pipes
Data Source
AI summary
Suppressed is damage of a semiconductor wafer due to charging of a cleaning liquid used in a single wafer type wafer cleaning step.A chemical solution discharged from a tip of a cleaning nozzle is brought into contact with protrusions of wafer chucks to thereby let static electricity of the chemical solution go to the wafer chucks, and subsequently, the cleaning nozzle is moved above the wafer to supply the chemical solution onto a top surface of the wafer, thereby suppressing abnormal discharge (damage) of the wafer due to charging of the chemical solution.