Semiconductor Wafer Dicing with Laser-Induced Crack Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mechanical dicing of semiconductor substrates using sawing blades often results in broken diced surfaces, leading to faults in semiconductor chips.
Innovation Solution
A method involving laser dicing with a metal shield layer on the semiconductor substrate to control crack propagation, using a modified layer formed by laser irradiation and polishing to separate integrated circuit regions into chips, with a metal shield layer preventing laser leakage and scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical dicing using a sawing blade is used, then the dicing process can be performed, but the diced surface of the semiconductor chips may break causing faults
Solution Approach 1:
The patent replaces the mechanical dicing system (sawing blade) with a laser-based dicing system. The laser beam forms a modified layer inside the semiconductor substrate through optical energy, which then propagates cracks to separate the substrate without mechanical contact. This substitution eliminates the mechanical stress that causes diced surface breakage while maintaining effective separation of integrated circuit regions.
Solution Approach 2:
The patent introduces a metal shield layer as an intermediary component between the laser source and the integrated circuit regions. This shield layer absorbs or blocks excess laser energy, preventing direct laser impact on the integrated circuits while allowing the laser to form the modified layer in the dicing region. The intermediary shield enables laser dicing to proceed without causing faults in the semiconductor chips.
2Reliability
If laser dicing is used to avoid mechanical contact, then chip fault rate decreases, but laser leakage and scattering may cause faults in integrated circuits
Solution Approach 1:
The metal shield layer serves as a protective intermediary positioned between the laser beam and the integrated circuit regions. It selectively blocks laser energy from reaching the integrated circuits while allowing the laser to create the modified layer in the dicing region. This intermediary structure resolves the contradiction by enabling laser dicing benefits while preventing laser-induced damage to sensitive components.
Solution Approach 2:
The metal shield layer is strategically positioned only in specific regions - covering the integrated circuit regions while leaving the dicing regions accessible to laser irradiation. This localized placement creates different functional zones: the shielded areas protect integrated circuits from laser harm, while the exposed dicing regions allow modified layer formation. This spatial differentiation of protection enables simultaneous achievement of fault reduction and laser safety.
3Object-affected harmful factors
If a metal shield layer is added to protect integrated circuits, then laser-induced faults are prevented, but device complexity increases
Solution Approach 1:
The metal shield layer performs multiple functions simultaneously: it shields integrated circuit regions from laser damage, defines dicing region boundaries, and may serve as an electrical ground or signal reference layer. By consolidating these functions into a single component, the patent minimizes the increase in device complexity while achieving comprehensive laser protection and process definition.
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
Reduces faults in semiconductor chips and improves electrical characteristics and production efficiency by controlling crack propagation and minimizing laser impact on integrated circuits.
Implementation Method 1
forming a modified layer by irradiating laser to an inside of the semiconductor substrate along the dicing region
Implementation Method 2
a metal shield layer provided on the active surface across at least a portion of the adjacent integrated circuit regions and the dicing region
Data Source
AI summary
There is provided a method of dicing a semiconductor wafer, which includes providing a semiconductor substrate having a plurality of integrated circuit regions on an active surface of the semiconductor substrate, a dicing regions provided between adjacent integrated circuit regions of the plurality of integrated circuit regions, and a metal shield layer provided on the active surface across at least a portion of the adjacent integrated circuit regions and the dicing region, forming a modified layer by irradiating laser to an inside of the semiconductor substrate along the dicing region, propagating a crack from the modified layer in a direction perpendicular to a major-axial direction of the metal shield layer by polishing an inactive surface opposing the active surface of the semiconductor substrate and forming semiconductor chips by separating the adjacent integrated circuit regions, respectively, based on the crack propagating from the modified layer.