Vacuum Chamber Particle Ejection Using Ion Neutralization and Nitrogen
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Solution Overview
Problem
Foreign matter attached to the inner walls of vacuum sample chambers or load-lock chambers in semiconductor inspection and measurement apparatuses can lead to a decrease in semiconductor device yield, as existing technologies do not effectively address the discharge of foreign matter from these chamber surfaces.
Innovation Solution
A vacuum processing apparatus is designed with a transport unit, a vacuum sample chamber, a preliminary exhaust chamber, a static charge eliminator, a nitrogen supply line, and a vacuum pump, along with a computer system to control these components. This apparatus executes charge elimination in foreign matter attached to the inner walls, introduces nitrogen to the chambers, and evacuates them to effectively discharge foreign matter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If foreign matter is discharged from the inner wall of vacuum chambers using existing methods (particle charger and electric field), then foreign matter floating in the chamber can be prevented, but foreign matter already attached to the inner wall cannot be removed
Solution Approach 1:
Instead of using positive ions to repel foreign matter (conventional method), the invention uses negative ions to attract and remove positively charged foreign matter attached to the inner wall. This reverse approach enables removal of adhered foreign matter while maintaining prevention of new attachment
Solution Approach 2:
The invention changes the polarity parameter of the ion source from positive to negative, and adjusts the ion generation conditions to create a controlled negative ion environment that selectively removes foreign matter without affecting the wafer processing
2Reliability
If nitrogen is supplied to the vacuum chamber to discharge foreign matter, then foreign matter can be removed from inner walls, but the vacuum state is temporarily disrupted
Solution Approach 1:
The foreign matter removal operation is performed in advance during the vacuum establishment phase, before the wafer is transferred to the vacuum chamber. This preliminary cleaning action eliminates the need for separate cleaning cycles that would disrupt production timing
Solution Approach 2:
Nitrogen gas is used as an intermediary medium to transport and remove foreign matter from the inner wall. The nitrogen flows through the chamber, carrying detached foreign matter out through the exhaust system without requiring direct mechanical contact
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 described solution reduces foreign matter attached to the inner walls of vacuum sample chambers or load-lock chambers, thereby minimizing the risk of foreign matter attachment to wafers and enhancing the yield of semiconductor devices.
Implementation Method 1
a static charge eliminator configured to eliminate charge in foreign matter attached to an inner wall of at least one of the preliminary exhaust chamber or the vacuum sample chamber
Implementation Method 2
a vacuum pump configured to evacuate the preliminary exhaust chamber and the vacuum sample chamber
Data Source
AI summary
The present invention reduces the foreign matter that has stuck to the inner wall of a vacuum sample chamber 5 or a load lock chamber 4. A vacuum processing device 5 comprises a conveyance robot 3, the vacuum sample chamber 5, the load lock chamber 4, a neutralization device 23 for neutralizing the foreign matter having stuck to the inner wall of the load lock chamber 4 and/or the vacuum sample chamber 5, a valve 22 for dry nitrogen introduction to supply nitrogen to the load lock chamber 4 and the vacuum sample chamber 5, pumps 15 and 17 for exhausting the load lock chamber 4 and the vacuum sample chamber 5, and a control device 10. The control device 10 controls the conveyance robot 3, the neutralization device 23, the pumps 15 and 17, and the valve 22 for dry nitrogen introduction, thereby neutralizing the foreign matter having stuck to the inner wall of the load lock chamber 4 and/or the vacuum sample chamber 5, as well as performing air exhaustion of and nitrogen supply to the load lock chamber 4 and the vacuum sample chamber 5.