Laser-Assisted Die Bonding With Spatial Heating Control
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Solution Overview
Problem
Existing systems for laser bonding 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 laser assisted bonding system that controls laser irradiation spatially and temporally, using a beam filter to adjust laser beam intensity based on heat path density, and a spot size changer to vary beam size during the bonding process, ensuring uniform heating and reducing warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional laser bonding is used, then bonding speed is maintained, but uniform heating is not achieved causing die warping and connection failures
Solution Approach 1:
The patent applies local quality by varying laser beam intensity across different regions of the semiconductor die based on heat path density. Areas with higher heat path density receive lower laser intensity, while areas with lower heat path density receive higher intensity, achieving uniform temperature distribution and preventing die warping while maintaining bonding reliability
Solution Approach 2:
The patent changes laser beam parameters (intensity distribution and spot size) dynamically during the bonding process. By adjusting these parameters based on real-time temperature feedback and heat path density mapping, the system achieves uniform heating without causing die warping or connection failures
2Temperature
If uniform laser intensity is applied, then processing is simple, but heat accumulation in high heat path density areas causes overheating and bonding defects
Solution Approach 1:
The patent implements feedback control by monitoring temperature distribution during laser bonding and adjusting laser beam intensity accordingly. Temperature sensors detect hot spots in high heat path density areas, and the control system dynamically reduces laser intensity in those regions, preventing overheating while maintaining uniform temperature distribution
Solution Approach 2:
The patent performs preliminary mapping of heat path density across the semiconductor die before bonding begins. This pre-characterization data is used to pre-calculate the optimal laser intensity distribution pattern, allowing the system to compensate for uneven heat accumulation before it occurs during the actual bonding process
3Productivity
If high laser power is used for fast bonding, then productivity increases, but die warping and mechanical connection failures occur
Solution Approach 1:
The patent uses pulsed laser bonding with periodically modulated beam intensity. Instead of continuous high power application, the laser delivers controlled pulses with optimized duty cycle, allowing heat to distribute uniformly between pulses while maintaining high overall bonding speed. This periodic action prevents thermal runaway and die warping that would occur with sustained high power
Solution Approach 2:
The patent employs dynamic laser power adjustment during the bonding process. The system continuously monitors bonding progress and die temperature, dynamically modifying laser power levels to maintain optimal bonding conditions. This dynamic control enables fast bonding speeds while preventing excessive heat accumulation that would cause warping or connection failures
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 system enhances bonding reliability by preventing die tilting and warping, improving mechanical and electrical connections, and increasing device quality and manufacturability.
Implementation Method 1
a laser beam irradiating a semiconductor die
Implementation Method 2
a beam filter in the laser beam path to filter a wavelength of the laser beam
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.