Wafer Gettering Sink Layer via Laser Deterioration
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Solution Overview
Problem
The grinding distortion layer formed on semiconductor wafers during thickness reduction compromises the deflective strength and gettering sink effect, leading to reduced device functionality when removed through polishing or etching.
Innovation Solution
A method involving a grinding distortion layer removal step followed by a gettering sink effect layer formation using a laser beam with a permeable wavelength, creating a deteriorated layer inside the substrate to maintain the gettering sink effect while stabilizing the deflective strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the grinding distortion layer is removed by polishing or etching after the rear surface is ground, then the deflective strength of each chip becomes stable, but the gettering sink effect of the grinding distortion layer is lost and the function of each device is lowered
Solution Approach 1:
The invention extracts the harmful grinding distortion layer from the rear surface through polishing or etching to improve deflective strength, while simultaneously creating a new gettering sink effect layer through laser processing to replace the lost gettering function. This separation of functions resolves the contradiction between strength stability and gettering effect retention.
Solution Approach 2:
The laser-induced deteriorated layer acts as an intermediary structure that provides the gettering sink effect without requiring the original grinding distortion layer. This intermediary layer enables the system to achieve both stable deflective strength (through removal of the harmful layer) and retained gettering function (through the new laser-created layer).
2Length of moving object
If the thickness of the semiconductor wafer is reduced to 100 μm or less by grinding, then the size and weight of each semiconductor chip is reduced, but the grinding distortion layer greatly reduces the deflective strength of the semiconductor chips
Solution Approach 1:
The invention extracts and removes the harmful grinding distortion layer through polishing or etching after thinning the wafer to 100 μm or less. This removal eliminates the source of strength reduction while preserving the benefits of reduced wafer thickness and weight.
Solution Approach 2:
The invention performs preliminary removal of the grinding distortion layer through polishing or etching before final chip division. This preliminary action prevents the distortion layer from compromising chip strength while maintaining the reduced thickness achieved through grinding.
3Reliability
If a laser beam is applied to form a gettering sink effect layer, then the gettering sink effect is maintained, but additional processing steps are required
Solution Approach 1:
The invention replaces traditional mechanical or chemical methods of creating gettering layers with laser beam processing. The laser provides a non-contact, precise, and controllable method to create the deteriorated layer that serves as the gettering sink effect layer, maintaining reliability while offering process flexibility.
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 stabilizes the deflective strength of semiconductor chips and maintains the gettering sink effect, ensuring the functionality of devices by forming a deteriorated layer within the chips that acts as a gettering sink effect layer.
Implementation Method 1
applying a laser beam of a wavelength having permeability for the substrate of the wafer which has undergone the grinding distortion layer removing step, with its focal point set to the inside of the substrate to form a deteriorated layer in the inside of the substrate
Data Source
AI summary
A water processing method for providing a gettering sink effect to a wafer having a plurality of streets which are formed in a lattice pattern on the front surface of a substrate and devices which are formed in a plurality of areas sectioned by the plurality of streets, comprising the steps of removing distortion produced on the rear surface of the substrate of the wafer whose rear surface of the substrate has been ground to a predetermined thickness; forming a gettering sink effect layer by applying a laser beam of a wavelength having permeability for the substrate of the wafer which has undergone the distortion removing step, with its focal point set to the inside of the substrate to form a deteriorated layer in the inside of the substrate; and dividing the wafer which has undergone the gettering sink effect layer forming step, into individual chips along the streets.