Semiconductor Wafer Dicing with Laser-Modified Layers
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Solution Overview
Problem
Conventional semiconductor wafer dicing techniques, such as blade dicing, result in chipping due to stress at the interface between different physical properties, which affects the quality and characteristics of semiconductor elements, especially as design rules become finer and more complex.
Innovation Solution
A semiconductor wafer with modified layers formed by laser radiation on both sides of the dicing area and near the semiconductor elements, which are displaced from each other, to minimize the formation of new interfaces and reduce stress during cutting, thereby preventing chipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If blade dicing is used to divide semiconductor elements, then productivity is improved, but chipping occurs on the cut surfaces due to stress at interfaces between materials with different physical properties
Solution Approach 1:
A modified layer is formed in advance in the dicing area through laser radiation or ion implantation before the actual dicing process. This preliminary modification creates a layer with different mechanical properties that prevents stress concentration and chipping during subsequent blade dicing operations.
Solution Approach 2:
The physical and mechanical parameters of the dicing area are changed by forming a modified layer with altered crystallinity, density, or hardness through laser radiation or ion implantation. This parameter change allows the dicing area to withstand cutting stresses without generating chipping that would affect the semiconductor elements.
2Object-affected harmful factors
If the width of the dicing area is increased to provide clearance for chipping, then chipping is contained, but the area occupied by semiconductor elements is reduced
Solution Approach 1:
By modifying the physical parameters of the dicing area through laser radiation or ion implantation, the modified layer absorbs cutting stresses and contains chipping within itself. This allows the dicing area width to be minimized while still preventing chipping from reaching the semiconductor elements, thereby maximizing the effective area.
3Object-affected harmful factors
If plasma or ion implantation is used to form a modified layer on the dicing area, then chipping is suppressed, but new interfaces with different physical properties are created which may become new stress points
Solution Approach 1:
The modified layer is formed with controlled parameters such as depth, density, and crystallinity through laser radiation or ion implantation. By optimizing these parameters, the modified layer provides chipping suppression while minimizing the creation of additional stress-prone interfaces. The modification is confined to the dicing area and does not extend into the semiconductor element effective areas.
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 solution effectively suppresses chipping during dicing and assembly of semiconductor chips by reducing stress at the machining point, improving the quality of machining and preventing chipping from progressing into the semiconductor elements.
Implementation Method 1
forming at least a modified layer at least partially in the semiconductor substrate in the dicing area and near the semiconductor elements
Data Source
AI summary
A modified layer 5 and an altered layer 8 are formed outside a dicing point of a dicing area 3. Thus without forming another interface between different physical properties on the dicing point, it is possible to prevent chipping from progressing along a crystal orientation from an interface between a semiconductor element 2 and a semiconductor substrate 1 and from a surface of the semiconductor element during dicing, thereby suppressing the development of chipping to the semiconductor element.