Semiconductor Chip Side Face Modified Layers for Strength and Adhesion
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Solution Overview
Problem
The existing dicing technique for semiconductor wafers, which uses a laser beam to cut and modify the crystals, results in improved adhesiveness and impurity gettering but reduces the mechanical strength of semiconductor chips, leading to potential defects and issues with package resin adhesion and impurity ingress.
Innovation Solution
A semiconductor device with a four-layer structure on its side faces, comprising first and second modified layers formed by the dicing laser and cleavage faces, which balances mechanical strength with impurity gettering and adhesiveness by strategically placing energy-absorbing films and insulation layers to manage crystal defects and impurity entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a modified layer is formed on the side faces of semiconductor chips by laser beam dicing, then adhesiveness with package resin and impurity gettering effect are improved, but the strength of the semiconductor chip is decreased
Solution Approach 1:
The patent applies local quality by creating different types of modified layers at different locations on the side face. The first modified layer (formed deeper) provides impurity gettering, while the second modified layer (formed shallower) provides adhesiveness enhancement. This spatial differentiation of layer properties allows simultaneous achievement of multiple functions without compromising chip strength uniformly across the entire side face.
Solution Approach 2:
The patent segments the modified layer into two distinct layers with different characteristics and functions. The first modified layer is formed at a deeper position with different crystal defect density compared to the second modified layer at a shallower position. This segmentation allows each layer to be optimized for its specific function while collectively solving the contradiction between adhesiveness and strength.
2Object-affected harmful factors
If a modified layer is formed on the side faces of semiconductor chips by laser beam dicing, then impurity gettering effect is improved, but the strength of the semiconductor chip is decreased
Solution Approach 1:
The patent uses local quality by positioning the first modified layer deeper in the substrate where it can effectively trap impurities entering from the side face. The second modified layer is positioned shallower to maintain structural integrity. This localized functional assignment allows impurity gettering without uniform weakening of the chip structure.
Solution Approach 2:
The patent segments the side face structure into multiple layers with different depths and properties. The first modified layer at greater depth serves as the primary impurity barrier, while the second modified layer closer to the surface maintains mechanical strength. This segmentation enables targeted impurity prevention without compromising overall chip strength.
3Productivity
If laser beam is emitted to modify crystals in the dicing area, then the semiconductor wafer is split into pieces, but the mechanical strength of resulting chips is reduced
Solution Approach 1:
The patent applies local quality by controlling the laser beam to create modified layers at specific depth positions during the dicing process. The first modified layer is formed at a deeper position to facilitate wafer splitting, while the second modified layer is formed at a shallower position to preserve chip strength. This localized control of modification depth allows efficient dicing without excessive strength reduction.
Solution Approach 2:
The patent segments the laser modification process into two distinct stages or layers. The first modification occurs at greater depth to enable effective wafer separation, while the second modification occurs at shallower depth to maintain structural integrity. This segmented approach to laser processing achieves both high dicing productivity and acceptable chip strength.
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 structure maintains mechanical strength while enhancing adhesiveness with package resin and restricting impurity ingress, thereby reducing defects and improving the reliability of semiconductor chips.
Implementation Method 1
a semiconductor wafer is cut into pieces of semiconductor chips by emitting a laser beam to a dicing area of the semiconductor wafer. In the dicing technique, crystals inside the semiconductor wafer are modified by the laser beam
Implementation Method 2
crystals inside the semiconductor wafer are modified by the laser beam and then, from the modified portions, the semiconductor wafer is split into the pieces of the semiconductor chips
Implementation Method 3
An energy absorbing film is provided on the first face, to absorb optical energy to generate heat
Implementation Method 4
On the side faces of each semiconductor chip manufactured in the above way, a modified layer by means of the laser beam improves adhesiveness with a package resin
Implementation Method 5
a modified layer by means of the laser beam improves adhesiveness with a package resin and also improves an impurity gettering effect
Data Source
AI summary
A semiconductor device is provided with a semiconductor substrate. A semiconductor element is provided on a first face of the semiconductor substrate. An energy absorbing film is provided on the first face, to absorb optical energy to generate heat. A first insulation film is provided on the semiconductor element and on the energy absorbing film. A second insulation film is provided on a second face of the semiconductor substrate, the second face being opposite to the first face. A first modified layer is provided on a side face of the semiconductor substrate, the side face being located between an outer edge of the first face and an outer edge of the second face. A second modified layer is provided on the side face between the energy absorbing film and the first modified layer. A cleavage face is provided on the side face between the first and second modified layers.