Laser-Assisted Bonding Beam Alignment for Thin Die Protection
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Solution Overview
Problem
Current methods for die-beam alignment in laser-assisted bonding are prone to human error and lack a defined metric for quantitative evaluation, leading to potential misalignment and damage to thin semiconductor dies and interconnect layers during the reflow process.
Innovation Solution
A method using cameras and computer algorithms to generate calibration equations for precise alignment of the laser beam with respect to the semiconductor die, ensuring accurate positioning and rotation, thereby improving the alignment process beyond visual inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual inspection by human technician is used for die-beam alignment, then the alignment process is simple and quick, but the alignment precision is low and prone to human error
Solution Approach 1:
The patent replaces the mechanical/visual inspection system with an optical measurement system. Cameras capture images of the die and beam positions, and computer algorithms automatically calculate alignment metrics, substituting human visual inspection with an automated optical-mechanical system that provides quantitative measurement.
Solution Approach 2:
The patent creates optical copies (images) of the physical die and laser beam positions using cameras. These image copies are then processed by computer algorithms to determine alignment, allowing measurement without direct physical contact and enabling automated analysis of position and orientation.
2Reliability
If human visual inspection is used for alignment, then no complex equipment is needed, but the reliability of alignment is low due to lack of defined metrics
Solution Approach 1:
The patent implements feedback by capturing actual alignment data through cameras, comparing it against target positions, and using computer algorithms to calculate quantitative alignment metrics. This feedback loop enables automated determination of whether alignment meets specified criteria, replacing subjective human judgment with objective measured feedback.
Solution Approach 2:
The alignment system performs self-service by automatically capturing images, processing them through algorithms, calculating alignment metrics, and determining alignment status without requiring human intervention. The system serves itself by providing complete automated measurement and evaluation.
3Productivity
If misalignment occurs in laser-assisted bonding, then the process is faster than reflow oven, but thin die and interconnect layers are damaged
Solution Approach 1:
The patent performs preliminary alignment measurement and verification before the laser-assisted bonding process. By using cameras to capture positions and computer algorithms to calculate alignment metrics in advance, the system ensures proper alignment is established before thermal energy is applied, preventing damage to thin structures.
Solution Approach 2:
The patent replaces manual visual alignment with an automated optical measurement and calculation system. Cameras and computer algorithms automatically determine alignment status, eliminating human error and ensuring consistent, accurate alignment that protects thin die and interconnect layers during the high-speed bonding process.
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 ensures precise alignment of the laser beam with the semiconductor die, reducing manufacturing defects and maintaining thermal energy within desired areas, enhancing the reliability and efficiency of the laser-assisted bonding process.
Implementation Method 1
LAB uses a laser to apply energy directly to the back side of the die being mounted, which is converted to thermal energy to reflow solder bumps on the front side of the die
Implementation Method 2
energy directly to the back side of the die being mounted, which is converted to thermal energy
Implementation Method 3
The assembly is heated in an oven to reflow the solder bumps and thereby attach the semiconductor die to the substrate
Data Source
AI summary
A method of making a semiconductor device involves the steps of disposing a first semiconductor die over a substrate and disposing a beam homogenizer over the first semiconductor die. A beam from the beam homogenizer impacts the first semiconductor die. The method further includes the steps of determining a positional offset of the beam relative to the first semiconductor die in a number of pixels, using a first calibration equation to convert the number of pixels into a distance in millimeters, and moving the beam homogenizer the distance in millimeters to align the beam and first semiconductor die.