Laser-Assisted Die Bonding Using Beam Filters to Prevent Warping
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Solution Overview
Problem
Current systems and methods for laser bonding of semiconductor die to a substrate are inadequate, leading to potential connection or device failures due to uneven heating and warping of the semiconductor die.
Innovation Solution
A system and method that control and enhance laser irradiation of semiconductor die spatially and temporally, using a beam filter to customize laser beam intensity for different regions, and a beam homogenizer to convert Gaussian beams into flat-top beams, ensuring uniform heating and reducing warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional laser bonding is used to bond semiconductor die to substrate, then bonding speed can be maintained, but uneven heating and warping occur leading to connection or device failures
Solution Approach 1:
The patent applies local quality by using a beam filter with spatially varying optical properties to create non-uniform laser beam intensity distribution. Different regions of the semiconductor die receive different laser energy densities, with higher energy to regions that require more heating and lower energy to regions that would overheat, thereby achieving uniform overall heating and preventing warping while maintaining bonding reliability
Solution Approach 2:
The patent changes the spatial distribution parameter of laser beam intensity by introducing a beam filter with specific optical absorption characteristics. The filter modifies the Gaussian beam profile to create a customized intensity distribution pattern that compensates for thermal conduction effects and achieves uniform heating across the die surface, resolving the contradiction between bonding speed and heating uniformity
2Use of energy by moving object
If Gaussian laser beam is used for bonding, then laser energy can be concentrated, but non-uniform heating and die warping are caused
Solution Approach 1:
The beam filter creates local quality variations in the laser beam by having different optical absorption coefficients at different spatial locations. This results in a customized intensity distribution where energy concentration is optimized for each region of the die, preventing overheating in some areas while ensuring sufficient heating in others, thereby maintaining die flatness while improving energy utilization
Solution Approach 2:
The patent converts the inherently non-uniform Gaussian beam profile, which is typically considered a disadvantage, into a beneficial customized intensity distribution. By strategically designing the beam filter to complement the Gaussian profile, the system transforms the concentrated center energy into a controlled spatial distribution that achieves uniform heating and prevents warping
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 solution prevents or reduces tilting and warping of semiconductor die, improving the reliability and quality of the bonding process by ensuring uniform heating and consistent interconnection structure formation.
Implementation Method 1
a beam homogenizer to convert Gaussian beams into flat-top beams
Implementation Method 2
irradiating the semiconductor die with a laser beam
Implementation Method 3
A laser beam absorbing layer may be formed on the semiconductor die
Data Source
AI summary
A system and method for laser assisted bonding of semiconductor die. As non-limiting examples, various aspects of this disclosure provide systems and methods that enhance or control laser irradiation of a semiconductor die, for example spatially and/or temporally, to improve bonding of the semiconductor die to a substrate.