Semiconductor Die Singulation via Laser Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for singulating semiconductor die from a wafer, such as scribing or laser scribing, are inefficient, leading to non-uniform separation, high equipment costs, and reduced manufacturing throughput due to wide scribe lines and lengthy processing times.
Innovation Solution
A method involving the formation of narrow singulation openings through a semiconductor wafer using a combination of etching processes, including a fluorine-based anisotropic reactive ion etch and the Bosch process, to achieve precise and uniform separation of die, with the aid of reduced thickness conductor regions for efficient die singulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If diamond cutting wheel scribing is used to singulate die, then die can be separated from wafer, but scribe line width is large (150 microns) consuming excessive wafer area
Solution Approach 1:
The patent replaces the mechanical diamond cutting wheel system with a laser-based system. The laser beam focuses energy to ablate material along the scribe line, achieving precise singulation without the mechanical contact and wide kerf of diamond wheels. This substitution enables narrow scribe lines that conserve wafer area while maintaining singulation precision.
2Manufacturing precision
If diamond cutting wheel scribing is used to singulate die, then die can be separated from wafer, but processing time exceeds one hour reducing manufacturing throughput
Solution Approach 1:
The patent replaces the mechanical diamond cutting wheel system with a laser-based system. The laser beam focuses energy to ablate material along the scribe line, achieving precise singulation without the mechanical contact and wide kerf of diamond wheels. This substitution enables narrow scribe lines that conserve wafer area while maintaining singulation precision.
Solution Approach 2:
The patent employs periodic pulsed laser action to singulate die. By using short laser pulses with appropriate duty cycles, the system achieves efficient material removal while allowing thermal diffusion between pulses, preventing excessive heat accumulation. This periodic action reduces processing time compared to continuous mechanical scribing while maintaining singulation quality.
3Productivity
If laser scribing is used to singulate die, then processing time is reduced, but separation uniformity is poor and equipment cost increases
Solution Approach 1:
The patent optimizes laser parameters including pulse duration, pulse frequency, power level, and scanning speed to achieve uniform singulation. By carefully controlling these parameters, the system maintains consistent energy delivery along the scribe line, ensuring uniform material removal and consistent die separation. This parameter optimization resolves the issue of non-uniform separation while preserving the speed advantage of laser processing.
Solution Approach 2:
The patent implements feedback control mechanisms to monitor and adjust laser parameters during singulation. By measuring actual cutting depth, temperature, or other process variables in real-time and adjusting laser power or pulse characteristics accordingly, the system maintains uniform separation quality throughout the wafer processing, preventing the non-uniformity problems associated with uncontrolled laser scribing.
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 allows for faster and more uniform singulation of semiconductor die, increasing the number of die per wafer, reducing processing time, and minimizing equipment costs by using a precise etching process to form narrow singulation lines.
Implementation Method 1
a fluorine-based anisotropic reactive ion etch
Implementation Method 2
the Bosch process
Data Source
AI summary
In one embodiment, a method of singulating semiconductor die from a semiconductor wafer includes forming a material on a surface of a semiconductor wafer and reducing a thickness of portions of the material. Preferably, the thickness of the material is reduced near where singulation openings are to be formed in the semiconductor wafer.