Dual-Axis Laser Bonding for Uniform Solder Bump Heating
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Solution Overview
Problem
The increasing demand for flip-chip type substrates in semiconductor fabrication poses challenges in minimizing bonding defects during the laser bonding process of semiconductor chips, as existing methods struggle to uniformly heat solder bumps across multiple chips.
Innovation Solution
A laser bonding apparatus with a stage, a laser device, and dual rotation supports that allow the laser device to rotate in both azimuthal and polar angles, ensuring uniform heating of solder bumps on the sidewalls of semiconductor chips, minimizing defects by controlling the inclination and direction of the laser beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a stationary laser device is used to heat solder bumps, then the device structure is simple, but the heating uniformity across multiple semiconductor chips is poor
Solution Approach 1:
The laser device is made rotatable through a rotation support mechanism that enables azimuthal rotation, allowing the laser beam to dynamically adjust its irradiation angle and position on the semiconductor chips. This dynamic positioning capability enables uniform heating across multiple chips by sequentially irradiating different regions, resolving the contradiction between heating uniformity and device complexity.
2Reliability
If the laser beam irradiates only the top surface of semiconductor chips, then the device structure is simple, but bonding defects occur due to irregular melting of solder bumps
Solution Approach 1:
The rotation support enables the laser device to change irradiation angles dynamically, allowing the laser beam to irradiate not only the top surface but also the sidewalls of the semiconductor chips. This multi-angle irradiation ensures uniform melting of solder bumps, preventing bonding defects and improving reliability without requiring complex multi-device configurations.
3Manufacturing precision
If multiple laser devices are used to heat multiple semiconductor chips simultaneously, then heating uniformity improves, but the device complexity and cost increase
Solution Approach 1:
A single laser device is made multi-functional through the rotation support mechanism, enabling it to irradiate multiple semiconductor chips at different positions and angles sequentially. This single device performs the function that would otherwise require multiple stationary laser devices, achieving heating uniformity across multiple chips while reducing device complexity and cost.
Solution Approach 2:
The rotatable laser device dynamically repositions itself to irradiate different chips and regions, replacing the need for multiple simultaneous laser devices. The dynamic motion allows one device to cover the work area that would require multiple devices, achieving the same heating uniformity effect with reduced system complexity.
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 apparatus effectively prevents or minimizes bonding defects by uniformly heating solder bumps across multiple semiconductor chips, ensuring reliable chip-to-substrate bonding without irregular melting, thus enhancing the quality of the bonding process.
Implementation Method 1
a laser device on the stage, the laser device configured to irradiate a laser beam onto the substrate
Implementation Method 2
The solder bumps may be melted with radiation heat from the laser or Joule's heat from electric power to thereby bond the semiconductor chip to the substrate
Implementation Method 3
a first rotation support outside of the stage, the first rotation support configured to drive the laser device to rotate in an azimuthal angle direction; and a second rotation support configured to support the laser device and configured to drive the laser device to rotate in a polar angle direction intersecting the azimuthal angle direction
Data Source
AI summary
Disclosed are laser bonding apparatuses and methods, The laser bonding apparatus comprises a stage configured to receive a substrate, a laser device that may be disposed on the stage and is configured to irradiate a laser beam onto the substrate, a first rotation support disposed outside of the stage and is configured to drivee the laser device to rotate in an azimuthal angle direction, and a second rotation support configured to support the laser device and configured to drive the laser device to rotate in a polar angle direction intersecting the azimuthal angle direction.