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 adherence, leading to quality issues in the 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, a modified layer removing step with water-soluble resin, and a dividing step using an expandable tape to prevent dust adherence and chipping, ensuring clean separation of image sensor chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a dicing apparatus 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 causing quality degradation
Solution Approach 1:
The division process is segmented into multiple stages: first forming cut grooves in the glass substrate, then forming division start points in the wafer, and finally expanding the tape to complete separation. This staged approach prevents chipping by preparing the structure progressively rather than applying force all at once.
Solution Approach 2:
Cut grooves are formed in the glass substrate before the actual division, and division start points are created in the wafer beforehand. These preliminary actions prepare the laminate structure to divide cleanly when the tape is expanded, preventing chipping during the final separation.
2Productivity
If a laser beam is used to form a modified layer in the wafer, then the laminate can be divided, but dust drops from the modified layer and adheres to the image sensor chip causing quality degradation
Solution Approach 1:
The modified layer, which is the source of dust contamination, is completely removed from the wafer after serving its purpose as a division start point. This extraction eliminates the harmful dust source while maintaining the beneficial division capability.
Solution Approach 2:
The modified layer is discarded after use as a division start point. The cutting blade removes and discards this layer, which has completed its function, thereby eliminating the source of dust contamination that would otherwise adhere to the image sensor chips.
3Ease of manufacture
If the glass substrate is cut from the glass side, then cut grooves can be formed, but the structure becomes unstable during subsequent processing
Solution Approach 1:
The expandable tape acts as an intermediary supporting structure. After cut grooves are formed, the tape is attached to the laminate and expanded to provide stable support during subsequent processing steps, preventing instability while allowing the cut grooves to be properly formed.
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 degradation by removing dust and chipping, maintaining the quality of image sensor chips during the 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
Implementation Method 2
cutting while supplying cutting water into which a water-soluble resin is mixed from the wafer side of the laminate, thereby removing the modified layer formed inside the wafer
Implementation Method 3
expanding the expandable tape, and dividing the laminate into individual image sensor chips
Data Source
AI summary
A laminate processing method includes a modified layer removing step of positioning a cutting blade to the region of the wafer corresponding to each of the division lines and cutting while supplying cutting water into which a water-soluble resin is mixed from the wafer side of the laminate, thereby removing the modified layer formed inside the wafer, a dividing step of, after the modified layer removing step is carried out, expanding the expandable tape, and dividing the laminate into individual image sensor chips, and a cleaning step of supplying cleaning water from the back surface of the wafer with a state in which the expandable tape is expanded being maintained, thereby cleaning the laminate.