Wafer Support Recess Gate Prevents Sputtering Arcing
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Solution Overview
Problem
Conventional sputtering apparatuses experience arcing between the deposition ring and cover ring, leading to contamination, reduced film thickness, and non-uniformity of the deposited barrier layer due to sputtered material deposition, which affects the efficiency of ion bombardment and film uniformity.
Innovation Solution
A wafer supporting device with a deposition ring having a recess and a cover ring with a corresponding gate that engages without contact, preventing sputtered material from depositing between the rings, thus eliminating arcing and enhancing film adhesion and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the deposition ring and cover ring are positioned close to each other to reduce deposition area, then deposition reduction is improved, but arcing occurs between the rings
Solution Approach 1:
An insulating layer is introduced between the deposition ring and cover ring to prevent arcing while maintaining their close positioning. This intermediary layer allows the rings to remain near each other for deposition control while blocking the electrical discharge path that causes arcing.
2Manufacturing precision
If the negative bias voltage is increased to improve ion bombardment efficiency, then film uniformity is improved, but arcing occurs more frequently
Solution Approach 1:
The insulating layer acts as a mediator that allows higher negative bias voltages to be applied without causing arcing. By preventing direct electrical contact between components, the system can operate at higher voltages needed for improved ion bombardment and film uniformity.
Solution Approach 2:
The introduction of the insulating layer changes the electrical parameters of the system, allowing the negative bias voltage to be increased beyond the previous arcing threshold while maintaining stable operation.
3Area of stationary object
If the deposition ring is made larger to cover more area, then pedestal protection is improved, but deposition on the ring increases
Solution Approach 1:
The harmful deposition accumulation is extracted or prevented by the insulating layer, which blocks the path of sputtered material from reaching the deposition ring while allowing the ring to maintain its large protective area.
4Loss of substance
If the cover ring is positioned closer to the deposition ring to reduce sputtered material deposition, then deposition control is improved, but arcing is caused
Solution Approach 1:
The insulating layer serves as a mediator that enables the cover ring to be positioned close to the deposition ring for better deposition control while preventing the harmful arcing effect through electrical isolation.
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
Prevents arcing, improves film thickness and uniformity, and reduces contamination, resulting in better sputtering results and ion bombardment efficiency for high uniformity requirements like Ta or TaN barrier layers.
Implementation Method 1
a pedestal such as an electrostatic chuck (E-chuck) 22 for attracting the wafer 30 with a direct current voltage
Implementation Method 2
a sputtering apparatus 10 comprises a chamber 12, a metal target 14 positioned in a top portion of the chamber 12
Implementation Method 3
a negative bias voltage is applied to the wafer 30 for attracting positive ions to attack a surface of the wafer 30. The attack causes a momentum transfer and makes the deposited molecules rearranged
Data Source
AI summary
A wafer supporting device of a sputter apparatus includes a pedestal positioned in a sputtering chamber and used to load a wafer for sputtering, a deposition ring having a recess positioned on a peripheral portion of the pedestal, and a cover ring positioned on the pedestal and the deposition ring. The cover ring has a gate corresponding to the recess.