Wafer Division Using Softenable Adhesive Tape for Debris Control
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Solution Overview
Problem
The existing laser processing method for wafer division generates breaking debris on the side surfaces of device chips, which can degrade the quality of the devices and cause issues in subsequent steps like bonding and packaging.
Innovation Solution
A wafer dividing method that involves applying a laser beam with a transmission wavelength to form modified layers inside the wafer, using an adhesive tape with a softenable adhesive layer to catch debris by expanding and heating the tape after division, preventing debris from depositing on the device surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If an adhesive tape is attached to the wafer and expanded to divide the wafer, then breaking debris are caught by the adhesive layer, but the process complexity increases
Solution Approach 1:
The adhesive tape combines multiple functions into a single component: it serves as both the force transmission medium for wafer division and the debris collection mechanism. The base sheet transmits expansion force while the adhesive layer captures debris, eliminating the need for separate debris collection systems and reducing overall process complexity despite the added tape component.
2Object-generated harmful factors
If the adhesive layer is softened by heating to catch debris, then the debris adhesion is improved, but the processing time increases
Solution Approach 1:
The adhesive layer is pre-heated before the wafer division process to ensure optimal adhesion properties are in place beforehand. This preliminary heating action allows the adhesive to be ready to capture debris immediately when breaking occurs during expansion, eliminating the need for post-division heating and reducing total processing time.
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
Prevents degradation of device quality by effectively catching debris between device chips, eliminating the risk of trouble in subsequent processing steps.
Implementation Method 1
applying a laser beam having a transmission wavelength to the wafer along the division lines in the condition where the focal point of the laser beam is set inside the wafer, thereby forming a plurality of modified layers inside the wafer along the division lines
Implementation Method 2
heating the adhesive tape to thereby soften the adhesive layer of the adhesive tape and make the softened adhesive layer enter the space between any adjacent ones of the device chips
Implementation Method 3
making the softened adhesive layer enter the space between any adjacent ones of the device chips obtained by the dividing step, thereby catching debris generated in the dividing step to the adhesive layer by adhesion
Data Source
AI summary
A wafer dividing method including a step of applying a laser beam to a wafer along division lines with the focal point of the laser beam set inside the wafer, thereby forming modified layers inside the wafer along the division lines; a step of attaching an adhesive tape to the wafer, the adhesive tape having a base sheet and an adhesive layer; a dividing step of applying an external force to the wafer by expanding the adhesive tape, thereby dividing the wafer along the division lines to obtain a plurality of device chips; and a debris catching step of heating the adhesive tape to thereby soften the adhesive layer such that it enters the space between any adjacent ones of the device chips obtained by the dividing step, thereby catching debris generated on the side surface of each device chip in the dividing step to the adhesive layer by adhesion.