Wafer Dicing via Laser Modified Regions and Strong Adhesive Tape
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Solution Overview
Problem
Conventional wafer processing methods are complex and result in defective chips due to contamination and inefficient chip quality, requiring re-attachment of tapes and weak adhesiveness leading to chip fracture and contamination issues during the dicing process.
Innovation Solution
A wafer processing method involving a back grinding tape with a strong adhesive layer attached to the front surface, where modified regions are formed using a laser beam, and the wafer is divided by applying a load from the back surface along the cut line, allowing for simplified processing and contamination removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional protective tape is attached to the front surface of the wafer during back-grinding, then the front surface is protected, but the tape exhibits weak adhesiveness causing chip fracture and contamination during dicing
Solution Approach 1:
The patent changes the adhesive parameter by using a tape with strong adhesiveness instead of conventional weak adhesive tape. This allows the tape to firmly hold the wafer during dicing operations, preventing chip fracture and contamination while maintaining protective function throughout the process.
Solution Approach 2:
The tape is designed to serve multiple functions: protecting the front surface during back-grinding, maintaining wafer integrity during dicing, and preventing contamination. The strong adhesive property enables the tape to perform all these functions simultaneously without requiring re-attachment or replacement.
2Ease of manufacture
If the protective tape is peeled off after back-grinding, then the process is simplified, but re-attachment is required for dicing increasing complexity
Solution Approach 1:
The tape is designed to serve multiple functions: protecting the front surface during back-grinding, maintaining wafer integrity during dicing, and preventing contamination. The strong adhesive property enables the tape to perform all these functions simultaneously without requiring re-attachment or replacement.
Solution Approach 2:
The tape is attached beforehand to the front surface and remains in place throughout both back-grinding and dicing operations. This preliminary attachment eliminates the need for re-attachment operations, simplifying the overall manufacturing process while ensuring continuous protection and stability.
3Productivity
If a break bar is pressed against the wafer from the back surface during dicing, then the wafer is divided along cut lines, but contamination adheres to the wafer causing defective chips
Solution Approach 1:
The strongly adhesive tape acts as an intermediary between the wafer and the external environment during dicing. It captures and holds contamination particles that would otherwise adhere to the wafer surface, preventing defective chips while allowing efficient dicing operations to proceed.
4Productivity
If conventional dicing methods are used after back-grinding, then the wafer can be divided, but the process becomes complex and chip quality is unstable
Solution Approach 1:
The tape is designed to serve multiple functions: protecting the front surface during back-grinding, maintaining wafer integrity during dicing, and preventing contamination. The strong adhesive property enables the tape to perform all these functions simultaneously without requiring re-attachment or replacement.
Solution Approach 2:
The strongly adhesive tape acts as an intermediary between the wafer and the external environment during dicing. It captures and holds contamination particles that would otherwise adhere to the wafer surface, preventing defective chips while allowing efficient dicing operations to proceed.
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 simplifies the wafer processing and ensures stable chip quality by adhering contamination to the tape and preventing abrupt chip inclination, thus eliminating defects from residual contamination.
Implementation Method 1
applying a laser beam from a back surface of the wafer along a cut line to form modified regions inside the wafer
Implementation Method 2
a tape attaching step of attaching a back grinding tape to a front surface of a wafer
Data Source
AI summary
To provide a wafer processing method which can simplify the wafer processing process and efficiently obtain chips of stable quality. A wafer processing method includes: a tape attaching step of attaching a back grinding tape to the front surface of a wafer; a modified region forming step of applying a laser beam from the back surface of the wafer along a cut line to form modified regions inside the wafer; a back surface processing step of processing the back surface of the wafer having the modified regions to reduce a thickness of the wafer; and a dividing step of, in a state in which the back grinding tape is attached to the front surface of the wafer, applying a load to the cut line from the back surface of the wafer to divide the wafer along the cut line and obtain individual chips.