Wafer Division via Laser Deteriorated Layer and Tape Expansion
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Solution Overview
Problem
Current methods for dividing semiconductor or optical device wafers, such as using a dicer or laser processing, face challenges with high hardness substrates like sapphire, leading to reduced productivity and chip damage during transportation due to contact between adjacent chips.
Innovation Solution
A method involving the formation of a deteriorated layer along dividing lines using a pulse laser beam, followed by affixing the wafer to a support tape with an adhesive layer, expanding the tape to create space between chips, and maintaining this space with external stimuli to prevent chip contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a dicer with a cutting blade is used to divide the wafer, then the wafer can be divided into individual chips, but the blade thickness requires dividing lines to have a width of about 50 μm, reducing productivity
Solution Approach 1:
The patent replaces the mechanical cutting blade system with a laser processing system. The laser beam forms deteriorated layers along the dividing lines without requiring physical contact, eliminating the need for thick blades and enabling much narrower dividing lines (e.g., 10 μm or less), thereby significantly improving productivity while maintaining precise chip separation.
Solution Approach 2:
The patent changes the physical state and properties of the material along the dividing lines by forming deteriorated layers through laser processing. This parameter change allows the wafer to be divided along precise lines with minimal width, as the deteriorated layers provide sufficient weakening for separation without requiring wide dividing lines.
2Productivity
If a support tape is expanded to give tensile force to the wafer for division, then the wafer can be divided into individual chips, but the expanded support tape shrinks when tensile force is released, causing chips to come into contact and get damaged
Solution Approach 1:
The patent applies preliminary anti-action by forming deteriorated layers along the dividing lines before expanding the support tape. These pre-formed deteriorated layers ensure that when the tape expands and then shrinks, the chips separate cleanly along the weakened lines without contacting each other, preventing damage during transportation.
Solution Approach 2:
The patent introduces deteriorated layers as an intermediary element between the support tape expansion force and the chip structure. These deteriorated layers act as a mediator that allows the tape to provide sufficient tensile force for division while preventing direct contact and damage between adjacent chips during tape shrinkage.
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 method effectively divides wafers into individual chips while maintaining a predetermined space between them, preventing damage during transportation by ensuring the chips do not come into contact.
Implementation Method 1
applying a pulse laser beam capable of passing through the workpiece with its focusing point set to the inside of the area to be divided
Implementation Method 2
continuously form a deteriorated layer in the inside of the workpiece along the dividing lines
Implementation Method 3
affixing the wafer to a support tape with an adhesive layer
Implementation Method 4
expanding the tape to create space between chips
Data Source
AI summary
A method of dividing a wafer having a plurality of dividing lines formed on the front surface in a lattice pattern and function elements formed in a plurality of areas sectioned by the plurality of dividing lines into individual chips, along the dividing lines, the method comprising the steps of forming a deteriorated layer by applying a laser beam capable of passing through the wafer along the dividing lines; expanding the support tape affixed to the wafer to divide the wafer into individual chips along the dividing lines where the deteriorated layer has been formed and to form a space between adjacent chips; and applying an external stimulus to an area, to which the wafer is affixed, of the support tape in the above state to cure the adhesive layer to maintain the space between adjacent chips.