Laminate Processing Method for Image Sensor Chips
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Solution Overview
Problem
Existing methods for dividing laminates with a glass substrate into image sensor chips often result in degradation due to chipping or dust contamination, affecting the quality of CMOS and CCD image sensor chips.
Innovation Solution
A laminate processing method involving a cut groove forming step using a cutting blade, a division start point forming step with a laser beam, and a water-soluble resin filling and removing process to prevent chipping and dust contamination, ensuring high-quality chip division.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a dicing apparatus with a cutting blade is used to divide the laminate, then the laminate can be divided into individual chips, but chipping occurs in the outer periphery of the image sensor chip on the wafer side
Solution Approach 1:
The patent segments the cutting process into two distinct stages: first forming cut grooves in the glass substrate using a cutting blade, then forming division start points in the wafer using laser irradiation. This segmentation allows each cutting method to operate in its optimal domain, preventing chipping while maintaining efficiency
Solution Approach 2:
The patent introduces water-soluble resin as an intermediary substance that fills the cut grooves and division start points. This resin acts as a buffer during the cutting process, preventing direct contact between the cutting blade and the chip edges, thereby eliminating chipping while allowing the cutting operation to proceed
2Manufacturing precision
If laser beam is used to form a modified layer in the wafer, then the laminate can be divided with the modified layer as a division start point, but dust is dropped from the modified layer causing quality degradation
Solution Approach 1:
The patent converts the harmful dust generated by laser-induced modified layer into a beneficial process feature. The water-soluble resin fills the dust-containing division start points, and the dust is subsequently removed together with the resin through water washing, transforming a contamination problem into a controlled removal process
Solution Approach 2:
The patent extracts the dust contamination problem from the cutting process by using water-soluble resin to encapsulate the dust in the division start points. The resin-dust mixture is then easily removed through water washing, separating the dust removal task from the main cutting operation
3Ease of manufacture
If the glass substrate is cut from the glass side, then the cut groove can be formed reaching the adhesive layer, but the wafer surface may be damaged during subsequent processing
Solution Approach 1:
The patent performs preliminary action by forming cut grooves in the glass substrate before performing laser irradiation on the wafer. This sequence ensures that the glass substrate provides structural support during laser processing, preventing wafer damage while enabling efficient groove formation
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 method effectively prevents chipping and dust-related degradation, maintaining the quality of image sensor chips by using a glass substrate with a transparent adhesive layer and a controlled division process.
Implementation Method 1
positioning a focal point of a laser beam having a transmission wavelength to the wafer inside a region of the wafer corresponding to each of the division lines from a back surface of the wafer, applying the laser beam thereto, continuously forming a modified layer inside the wafer
Data Source
AI summary
A laminate processing method includes a water-soluble resin filling step of filling a water-soluble resin in a division groove formed in a dividing step, a modified layer removing step of positioning a cutting blade in the division groove formed in a back surface of a wafer to cut the division groove in a state in which the water-soluble resin is solidified or half-solidified, thereby removing a modified layer, and a water-soluble resin removing step of supplying cleaning water from the back surface of the wafer with a state in which an expandable tape is expanded being maintained, thereby removing the water-soluble resin being filled in a cut groove and the division groove.