Chip-on-Wafer Bonding Surface Activation for Residue-Free Interfaces
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Solution Overview
Problem
Conventional methods for bonding chips with solder bumps onto a wafer using non-conductive resin result in resin residue at the bond interface, leading to reduced electroconductivity and mechanical strength due to the difficulty in removing the residue post-bonding.
Innovation Solution
A method involving surface activating treatment of chip and substrate metal regions with particles of predetermined kinetic energy, followed by hydrophilizing treatment with water, to create a clean bond interface without resin residue, enhancing electroconductivity and mechanical strength through precise contact and heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If non-conductive resin is used for chip bonding, then mechanical strength is improved, but electroconductivity at the bond interface deteriorates due to resin residue
Solution Approach 1:
The invention extracts and removes the harmful resin residue from the bond interface through a dedicated cleaning process using organic solvent and ultrasonic vibration, separating the bonding function from the contaminating effect, thereby restoring electroconductivity while preserving mechanical strength
Solution Approach 2:
The invention performs preliminary cleaning of the bond interface before final bonding occurs, using organic solvent application and ultrasonic treatment to prevent resin residue from compromising electroconductivity, rather than attempting remediation after bonding is complete
2Productivity
If packaging density is increased, then productivity is improved, but manufacturing precision deteriorates due to difficulty in removing flux residues from minute structures
Solution Approach 1:
The invention replaces manual or conventional mechanical cleaning methods with ultrasonic vibration technology, which uses high-frequency mechanical waves to dislodge flux residues from minute structures without requiring direct physical contact, thereby maintaining cleaning effectiveness as packaging density increases
Solution Approach 2:
The invention changes the physical parameters of the cleaning process by introducing ultrasonic frequency vibrations and controlling organic solvent properties, enabling effective removal of flux residues from increasingly minute bond structures as packaging density increases
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 method enables efficient bonding of chips onto a wafer with improved electroconductivity and mechanical strength, allowing for high packaging density and reliable electronic connections while avoiding resin residue issues.
Implementation Method 1
causing particles having a predetermined kinetic energy to collide with at least the metal region(s) of the chip-side-bond-surface to subject the metal region(s) to surface activating treatment
Implementation Method 2
causing water to adhere onto the metal region(s) to subject the metal region(s) to hydrophilizing treatment
Implementation Method 3
heating the resultant structure which includes the substrate and the chips fitted onto the substrate
Data Source
AI summary
[Problem] Provided is a technique for bonding chips efficiently onto a wafer to establish an electrical connection and raise mechanical strength between the chips and the wafer or between the chips that are chips laminated onto each other in the state that resin and other undesired residues do not remain on a bond interface therebetween.[Solution] A method for bonding plural chips each having a chip-side-bond-surface having metal regions to a substrate having plural bond portions has the step (S1) of subjecting the metal regions of the chip-side-bond-surface to surface activating treatment and hydrophilizing treatment; the step (S2) of subjecting the bond portions of the substrate to surface activating treatment and hydrophilizing treatment; the step (S3) of fitting the chips subjected to the surface activating treatment and the hydrophilizing treatment onto the corresponding bond portions of the substrate subjected to the surface activating treatment and the hydrophilizing treatment to bring the metal regions of the chips into contact with the bond portions of the substrate; and the step (S4) of heating the resultant structure, which includes the substrate, and the chips fitted onto the substrate.