Plasma Gas Oxide Removal in Thermocompression Bonding
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Solution Overview
Problem
Thermocompression bonding processes require the removal of oxide layers, which is typically achieved using fluxes, leading to increased costs, environmental impact, and inefficiencies due to the need for flux application and deflux processes.
Innovation Solution
The use of a localized reducing plasma gas to remove metal oxides prior to bonding, eliminating the need for fluxes and reducing the number of processing steps, thereby minimizing re-oxidation risks and equipment requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fluxes are used to remove oxide layers during thermocompression bonding, then oxide removal is achieved, but manufacturing costs increase and environmental impact worsens
Solution Approach 1:
The patent extracts and eliminates the flux application step from the thermocompression bonding process by using plasma gas to directly remove oxide layers. This removes the harmful substance (flux) and its associated costs while maintaining oxide removal effectiveness.
Solution Approach 2:
The patent changes the chemical environment from using liquid flux to using plasma gas (such as hydrogen plasma). This parameter change in the reactive species used for oxide removal eliminates the need for flux application and deflux processes, reducing manufacturing costs and environmental impact.
2Manufacturing precision
If fluxes are used to remove oxide layers, then oxide removal is achieved, but the number of processing steps increases
Solution Approach 1:
The patent removes the deflux processing step from the workflow by using plasma gas instead of liquid flux. Since plasma gas does not leave residues like liquid flux does, the separate deflux process becomes unnecessary, streamlining the overall process.
Solution Approach 2:
The patent combines the oxide removal function into the plasma treatment step itself, which is already part of the bonding process preparation. This merges what would otherwise be separate steps (flux application, oxide removal, deflux) into a more integrated process flow.
3Manufacturing precision
If fluxes are used for oxide removal, then oxide layers are removed, but re-oxidation risk increases
Solution Approach 1:
The patent uses plasma gas (such as hydrogen or inert gas plasma) to create a controlled atmospheric environment during oxide removal. This plasma environment prevents re-oxidation by maintaining reducing or inert conditions throughout the process, unlike liquid flux which requires subsequent protective handling.
Solution Approach 2:
The patent replaces the liquid flux chemical system with a plasma gas system. This substitution eliminates the need for liquid handling and associated contamination risks, while the plasma environment inherently protects against re-oxidation through its reactive species and atmospheric control.
4Manufacturing precision
If fluxes are used to remove oxide layers, then oxide removal is achieved, but equipment requirements and complexity increase
Solution Approach 1:
The patent eliminates the need for flux dispensing equipment and deflux processing equipment by using plasma gas. This extraction of the liquid flux system removes associated equipment complexity while maintaining oxide removal capability through plasma treatment.
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 significantly reduces manufacturing costs, conserves resources, and enhances throughput by directly removing oxide layers with high reactivity, resulting in a more efficient and cost-effective bonding process.
Implementation Method 1
The plasma gas can remove metal oxides from components prior to bonding
Implementation Method 2
a localized reducing plasma gas to remove metal oxides prior to bonding
Implementation Method 3
Two metals, e.g. gold (Au)-gold (Au), are brought into atomic contact applying force and heat simultaneously. The diffusion requires atomic contact between the surfaces due to the atomic motion.
Implementation Method 4
applying force and heat simultaneously
Implementation Method 5
applying force and heat simultaneously
Data Source
AI summary
Described herein are devices and techniques for thermocompression bonding. A device can include a housing, a platform, and a plasma jet. The housing can define a chamber. The platform can be located within the chamber and can be proximate a thermocompression chip bonder. The plasma jet can be located proximate the platform. The plasma jet can be movable about the platform. The plasma jet can include a nozzle arranged to direct a plasma gas onto the platform. Also described are other embodiments for thermocompression bonding.