Wafer Dicing with Planarized Grooves for Damage-Free Separation
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Solution Overview
Problem
In wafer dicing methods using laser processing, the surrounding area of the broken wafer is often damaged due to melting, affecting semiconductor devices, and existing methods struggle to precisely separate devices without causing damage.
Innovation Solution
A wafer dicing method involving the formation of internal cracks by radiating a laser beam along planarized grooves in the scribe lane area, using multiple laser devices for groove formation and planarization, allowing for precise separation of semiconductor devices without damaging surrounding areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a laser beam is used to break the wafer by heating and melting, then the wafer can be separated into individual devices, but the surrounding area is also melted causing damage to semiconductor devices
Solution Approach 1:
The dicing process is divided into multiple stages: first forming grooves partially through the wafer, then planarizing the lower surfaces, and finally forming internal cracks along the grooves. This segmentation allows precise control of the breaking process, separating the wafer only where needed while protecting surrounding devices
Solution Approach 2:
Grooves are formed in advance along the scribe lanes before the actual breaking process. These pre-formed grooves serve as guides for where the internal cracks will propagate, ensuring that the wafer breaks only at the intended locations and not damaging adjacent semiconductor devices
2Object-affected harmful factors
If stealth dicing is used to induce internal cracks by focusing laser beam inside the wafer, then device damage is reduced, but the process complexity increases
Solution Approach 1:
The complex stealth dicing process is broken down into distinct sequential steps: groove formation, planarization of lower surfaces, and internal crack formation. Each step uses optimized laser parameters specific to that operation, making the overall complex process more controllable and repeatable
Solution Approach 2:
The grooves act as intermediaries that facilitate the stealth dicing process. They provide pre-defined pathways that guide the internal cracks, reducing the complexity of directly focusing laser beams to induce cracks without any structural guidance
3Manufacturing precision
If multiple laser devices are used for groove formation and planarization, then separation precision is improved, but the manufacturing process becomes more complex
Solution Approach 1:
Multiple laser devices with different functionalities are integrated into a single dicing system. One laser device forms grooves while another planarizes surfaces, and both operations are performed in sequence on the same wafer, reducing the need for separate equipment and simplifying the overall manufacturing flow
Solution Approach 2:
The groove formation and planarization processes are combined into a single integrated workflow using multiple laser devices. The grooves formed by the first laser device are immediately planarized by the second laser device, creating a coordinated multi-step process that achieves high precision without requiring separate manufacturing stages
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 enhances the reliability of wafer dicing by minimizing damage to semiconductor devices and improving the precision of separation, enabling efficient manufacturing of semiconductor devices with reduced defects.
Implementation Method 1
a laser processing process includes a patterning process for forming a pattern on a surface of a workpiece, a process of modifying a property of a workpiece, such as wafer annealing, a molding process for changing a shape of a workpiece through heating and melting
Implementation Method 2
a stealth dicing process may be used to induce internal cracks by focusing a laser beam on the inside of the wafer
Data Source
AI summary
A wafer dicing method includes preparing a wafer having a plurality of device formation areas and a scribe lane area defining the plurality of device formation areas, forming a plurality of semiconductor devices in the plurality of device formation areas of the wafer, forming, in the scribe lane area, a plurality of first grooves partially passing through at least a portion of the wafer in a vertical direction, forming a plurality of second grooves by planarizing lower surfaces of the plurality of first grooves, forming one or more internal cracks in the wafer by radiating a laser beam along lower surfaces of the plurality of second grooves, and separating the plurality of semiconductor devices from each other along the one or more internal cracks.