Atmospheric Plasma Chip Bonding for Oxide-Free Interconnects
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Solution Overview
Problem
The formation of oxides on metal bumps and bonding pads hinders secure bonding in semiconductor devices, which is a challenge in three-dimensional integration processes such as flip-chip bonding, leading to unreliable electrical connections.
Innovation Solution
A system is employed to expose the semiconductor devices to a controlled plasma environment to remove oxides from metal bumps and bonding pads before bonding, using a plasma generation device within an enclosure maintained at atmospheric pressure with low oxygen concentration, followed by thermal compression bonding to form secure connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional flux-based bonding methods are used, then oxide removal can be achieved, but process complexity and contamination risk increase
Solution Approach 1:
The patent replaces the chemical flux-based oxide removal process with a plasma-based physical/chemical process. The plasma generation device creates a controlled plasma environment that removes oxides from metal bumps and bonding pads through ion bombardment and chemical reactions, eliminating the need for flux application, baking, and cleaning steps while achieving reliable bonding connections
Solution Approach 2:
The patent extracts and removes the harmful oxide layer from the bonding surfaces using plasma treatment before bonding occurs. The plasma environment selectively removes oxides from metal surfaces through oxidative reactions and physical sputtering, leaving clean metal surfaces ready for direct bonding without requiring additional flux materials
2Strength
If oxide removal is performed to ensure secure bonding, then bonding strength improves, but process time and temperature requirements increase
Solution Approach 1:
The patent performs oxide removal as a preliminary step before bonding by exposing the metal bumps and bonding pads to a controlled plasma environment. This pre-treatment cleans the surfaces in advance, ensuring that when bonding occurs, the metal surfaces are already clean and ready for immediate strong bonding without requiring extended process times
Solution Approach 2:
The patent changes the physical and chemical parameters of the bonding environment by introducing a plasma state with controlled temperature, pressure, and composition. The plasma provides localized high-energy conditions for oxide removal while maintaining overall process temperature control, enabling rapid oxide removal followed by efficient bonding at controlled temperatures
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 method effectively removes oxides, ensuring robust and reliable electrical connections between semiconductor chips and substrates, enhancing the integrity of three-dimensional semiconductor devices.
Implementation Method 1
a plasma generation device configured to supply a plasma to the chip or the substrate
Implementation Method 2
The formation of oxides on metal bumps and bonding pads hinders secure bonding
Implementation Method 3
followed by thermal compression bonding to form secure connections
Data Source
AI summary
A disclosed system is configured to bond a chip to a substrate and includes a chip processing subsystem that is configured to receive the chip and to expose the chip to a first plasma, and a substrate processing subsystem that is configured to receive the substrate and to expose the substrate to a second plasma. The system further includes a bonding subsystem that is configured to align the chip with the substrate, to force the chip and the substrate into direct mechanical contact with one another by application of a compressive force, and to apply heat to at least one of the chip or the substrate. Application of the compressive force and the heat thereby bonds the chip to the substrate. The first and second plasmas may include H2/N2, H2/Ar, H2/He, NH3/N2, NH3/Ar, or NH3/He and the chip and substrate may be maintained in a low oxygen environment.