Laser-Based Transparent Material Processing
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Solution Overview
Problem
Current mechanical methods for cutting optically transparent materials, such as those used in the microelectronics industry, generate significant debris and can cause thinner wafers to shatter, leading to increased costs and contamination issues.
Innovation Solution
The use of temporally and spatially overlapping nanosecond and ultrashort pulse laser sources to achieve high-speed and high-quality processing of transparent materials, including drilling, cutting, and micromachining, by delivering pulse pairs along a common propagation direction, which results in increased depthwise material modification and improved machining quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical dicing saw is used to cut thin transparent wafers, then cutting can be performed, but the wafers tend to shatter and significant debris is generated
Solution Approach 1:
The patent replaces the mechanical dicing saw system with a laser-based processing system. The laser beam interacts with the material through optical fields rather than mechanical contact, eliminating the generation of mechanical debris and preventing wafer shattering by using controlled laser-induced modifications instead of mechanical cutting forces.
Solution Approach 2:
The patent employs ultrashort pulse laser parameters (pulse duration in the femtosecond to picosecond range, high peak power, specific repetition rates) to achieve clean material modification without thermal damage. By carefully controlling laser parameters such as pulse width, energy density, and scanning speed, the process achieves precise cutting without generating debris or causing wafer failure.
2Productivity
If mechanical dicing saw is used for cutting, then material can be separated, but process cost increases due to debris management
Solution Approach 1:
The laser-based system eliminates the need for mechanical debris collection and management infrastructure. The non-contact nature of laser processing means no chips or swarf are generated that would require vacuum systems, conveyors, or manual removal, thereby reducing equipment complexity and operational costs while maintaining high cutting speeds.
3Manufacturing precision
If laser processing is used to achieve high machining quality, then edge quality improves, but processing speed may be limited
Solution Approach 1:
The patent uses pulsed laser operation with specific repetition rates (e.g., 100 kHz to 1 MHz) to deliver energy in controlled bursts. This periodic action allows the material to cool between pulses, preventing heat accumulation and maintaining edge quality, while the high repetition rate ensures rapid processing by delivering many pulses per second along the cut path.
Solution Approach 2:
The ultrashort pulses deliver energy so rapidly that the material response is immediate and localized, preventing heat diffusion to surrounding areas before the pulse sequence completes. This preliminary, ultra-fast energy deposition ensures clean edges are formed from the start of processing rather than requiring slow, cautious parameter adjustment.
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 method allows for precise and efficient processing of transparent materials with reduced heat accumulation effects, enabling the formation of fine pitch holes and trenches without significant damage, while maintaining high throughput and edge quality.
Implementation Method 1
temporally and spatially overlapping a series of nanosecond pulses from a nanosecond pulse (NS) laser source with a series of ultrashort pulses from an ultrashort pulse (USP) laser source can result in both substantially more depthwise material modification
Implementation Method 2
processing a material can include (but is not limited to) micromachining the material, forming kerfs or trenches in or on the material, physically modifying the material
Data Source
AI summary
In certain embodiments a method and system for laser-based material processing of a material is disclosed. In at least one preferred implementation temporally overlapping pulse series are generated with separate pulsed laser sources, for example nanosecond (NS) and ultrashort pulse (USP) sources (NS-USP). Pulses are delivered to the material as a series of spatially and temporally overlapping pulse pairs. The material can, but need not, be a transparent material. In some applications of transparent material processing, it was found the combination of pulses both substantially more material modification and high machining quality than obtainable with either individual pulse series taken alone. Other micromachining methods and arrangement are disclosed for formation of fine features on or within a substrate. Such methods and arrangements may generally be applied with a NS-USP combination, or with other sources.