Hybrid Laser-Plasma Wafer Dicing for Precision Separation
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Solution Overview
Problem
Current methods for dicing semiconductor wafers, such as scribing and sawing, often result in chipping, cracking, and waste of wafer real estate due to jagged separation lines and the need for additional spacing between dice, while plasma dicing faces limitations like high costs and production issues with metals like copper.
Innovation Solution
A hybrid method combining adaptive optics-controlled laser scribing and plasma etching, where a mask is patterned with a laser to expose regions between integrated circuits, allowing for precise and smooth separation of dice with reduced kerf width variation and improved sidewall smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If scribing or sawing is used to dice semiconductor wafers, then the wafer can be separated into individual dice, but chipping and cracking occur along the severed edges and additional spacing is required between dice
Solution Approach 1:
The patent replaces mechanical scribing and sawing systems with a laser-based system. The laser beam precisely ablates material along the street regions to create separation channels between dice, eliminating mechanical contact that causes chipping and cracking. The laser system uses controlled energy delivery to achieve clean separation without the need for additional spacing between dice.
Solution Approach 2:
The patent employs controlled laser parameters including pulse duration, power, and scanning speed to optimize the dicing process. By adjusting these parameters, the laser achieves precise material removal with minimal heat affected zone, producing clean edges without chipping or cracking while maximizing wafer utilization.
2Productivity
If sawing is used to dice semiconductor wafers, then thick wafers can be separated, but the blade thickness and required spacing waste significant wafer real estate
Solution Approach 1:
The patent replaces the mechanical saw blade with a laser beam for material removal. This substitution eliminates the physical blade thickness constraint and enables much narrower kerf widths. The laser can precisely define the separation path with minimal material removal, significantly increasing the number of dice that can be produced from each wafer.
Solution Approach 2:
The laser dicing process uses periodic pulsed energy delivery to remove material along the street regions. This periodic action allows precise control over the kerf width and depth, enabling thin but complete separation channels that maximize wafer real estate utilization while accommodating thick wafers.
3Manufacturing precision
If plasma dicing is used to separate integrated circuits, then separation can be achieved, but the process faces high costs and production issues with metals like copper
Solution Approach 1:
The patent replaces plasma-based dicing with a laser-based system. The laser directly ablates materials including metals like copper without the complexity and cost associated with plasma generation and control. This substitution simplifies the manufacturing process while maintaining precise separation capabilities and eliminating production issues with metallic interconnects.
Solution Approach 2:
The laser system uses a disposable or easily replaceable optical path rather than expensive plasma generation equipment. The laser beam can be precisely controlled and adjusted without complex plasma chemistry management, reducing both capital equipment costs and operational complexity while achieving the same separation precision.
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 enables precise and clean separation of semiconductor wafers with reduced chipping and cracking, optimizing die strength and wafer utilization, while minimizing the need for additional spacing, thus enhancing productivity and cosmetic quality.
Implementation Method 1
The mask is then patterned with an adaptive optics-controlled laser scribing process to provide a patterned mask with gaps, exposing regions of the semiconductor wafer between the integrated circuits
Implementation Method 2
The semiconductor wafer is then plasma etched through the gaps in the patterned mask to singulate the integrated circuits
Data Source
AI summary
Methods of dicing semiconductor wafers, each wafer having a plurality of integrated circuits, are described. In an example, a method of dicing a semiconductor wafer having a plurality of integrated circuits involves forming a mask above the semiconductor wafer, the mask composed of a layer covering and protecting the integrated circuits. The mask is then patterned with an adaptive optics-controlled laser scribing process to provide a patterned mask with gaps, exposing regions of the semiconductor wafer between the integrated circuits. The semiconductor wafer is then plasma etched through the gaps in the patterned mask to singulate the integrated circuits.