Argon-Free Dechucking Plasma for Low-k Wafer Protection
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Solution Overview
Problem
The challenge in semiconductor manufacturing is the sticking of substrates to electrostatic chucks due to residual electrical charges, which can cause damage and disrupt the processing flow, as existing plasma dechucking methods often result in feature damage on wafers.
Innovation Solution
A method using an argon-free plasma dechucking process that forms a low vacuum ultraviolet emission intensity plasma from gases like nitrogen, hydrogen, or tetrafluoromethane to safely dissipate residual charges on the substrate, minimizing damage to the wafer features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional plasma dechucking methods are used to remove residual charges, then substrate sticking is reduced, but feature damage on wafers occurs
Solution Approach 1:
The patent changes the chemical composition parameter of the dechucking gas from conventional argon-based plasma to an argon-free plasma (using gases like nitrogen, hydrogen, or tetrafluoromethane). This parameter change modifies the plasma's emission characteristics to reduce vacuum ultraviolet intensity, thereby preventing feature damage while maintaining effective charge dissipation for substrate release
Solution Approach 2:
The patent employs a composite approach by combining specific gases (nitrogen, hydrogen, or tetrafluoromethane) to create a dechucking plasma mixture that achieves both effective charge removal and reduced damaging radiation. The composite gas mixture produces a plasma with modified emission properties that are less harmful to wafer features compared to conventional argon plasma
2Object-affected harmful factors
If argon-free dechucking gas is used to form plasma, then feature damage is minimized, but the process complexity increases
Solution Approach 1:
The patent uses conventional, readily available gases (nitrogen, hydrogen, or tetrafluoromethane) that can be easily stored and delivered using existing infrastructure. These gases replace the need for specialized argon-based plasma systems, simplifying the overall system while achieving the desired low-damage dechucking effect
3Reliability
If dechucking plasma is formed to dissipate residual charge, then substrate release is achieved, but processing time increases
Solution Approach 1:
The patent maintains continuous plasma generation during the dechucking process, ensuring uninterrupted charge dissipation. The argon-free plasma formulation allows for efficient electron mobility and charge neutralization, maintaining fast substrate release rates without requiring extended processing times or additional process steps
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 reduces substrate sticking and damage during dechucking, allowing for efficient and reliable handling of wafers, thereby enhancing processing efficiency and maintaining feature integrity.
Implementation Method 1
A dechucking plasma is formed from the dechucking gas. The dechucking plasma is stopped. In another manifestation of the invention a method of dechucking a wafer, on which a silicon oxide based low-k is formed, held onto an electrostatic chuck by an electrostatic charge is provided. The electrostatic clamping voltage is removed.
Implementation Method 2
The low-k dielectric layer is etched.
Data Source
AI summary
A method of dechucking a wafer, with a low-k dielectric layer, held onto an electrostatic chuck by an electrostatic charge in a plasma chamber is provided. The electrostatic clamping voltage is removed. An essentially argon free dechucking gas is provided into the plasma chamber. A dechucking plasma is formed from the dechucking gas in the plasma chamber. The dechucking plasma is stopped.