Semiconductor Singulation via Laser Grooving and Stealth Dicing
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Solution Overview
Problem
Conventional mechanical dicing in semiconductor fabrication is inefficient, leading to wastage of silicon area and defects, while alternative methods like chemical etching and laser processes have limitations such as slow etching, inability to remove metal layers, and high residual stresses.
Innovation Solution
A method involving laser grooving to form narrow dicing channels, followed by stealth laser dicing and tape expansion to singulate semiconductor devices, which reduces silicon wastage and minimizes defects by using a combination of front side laser ablation and back side stealth dicing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical separation is used for singulation, then the separation process is simple and direct, but silicon area is wasted and production efficiency is reduced
Solution Approach 1:
The singulation process is divided into multiple stages: first forming grooves through the metallization layer, then creating a dicing layer through the substrate, and finally separating the dies along these pre-formed paths. This segmentation allows for more precise control over the separation process, reducing wasted silicon area while maintaining process simplicity
Solution Approach 2:
The invention introduces vertical dimensionality by forming grooves and dicing layers at different depths through the substrate. The groove is formed through the metallization layer while the dicing layer is formed through the substrate from the opposite side, creating a three-dimensional separation structure that maximizes silicon utilization
2Ease of manufacture
If conventional chemical etching or laser processes are used, then metal layers can be removed, but the etching speed is slow or residual stresses are high
Solution Approach 1:
The invention combines two different approaches: mechanical grooving through the metallization layer and laser-based dicing layer formation through the substrate. This hybrid approach leverages the speed of mechanical processes for metal removal while using laser precision for the final separation, avoiding the slow etching speeds and residual stresses of conventional single-method approaches
Solution Approach 2:
The invention replaces conventional chemical etching processes with a combination of mechanical grooving and laser-induced dicing layer formation. The laser process creates a dicing layer through the substrate without the slow etching rates and residual stress issues associated with chemical etching, while the mechanical grooving efficiently removes metallization material
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 effectively reduces silicon wastage, minimizes defects, and optimizes chip production efficiency by using laser grooving to create precise dicing channels and stealth dicing to avoid surface damage, enabling more efficient separation of semiconductor dies.
Implementation Method 1
forming a groove through a metallization layer disposed over a substrate using a first laser process
Implementation Method 2
forming a dicing layer under the groove within the substrate using a second laser process
Implementation Method 3
A crack is formed through the dicing layer to the groove by generating a tensile stress in the substrate
Data Source
AI summary
In one embodiment, a method of forming a semiconductor device comprises forming a groove on and/or over a first side of a substrate. A dicing layer is formed from a second side of the substrate using a laser process. The second side is opposite the first side. The dicing layer is disposed under the groove within the substrate. The substrate is singulated through the dicing layer.