Wafer Singulation Using Multiple Laser Grooves and Controlled Sawing
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Solution Overview
Problem
The increasing complexity of integrated circuit packages, which include multiple device dies and different technologies, poses challenges in efficient singulation processes, particularly in removing dielectric layers without penetrating the semiconductor substrate during sawing.
Innovation Solution
A method involving multiple narrow laser grooving processes with overlapping paths, followed by wide blade sawing, to create combined grooves that allow precise removal of dielectric layers without cutting through the semiconductor substrate, ensuring accurate separation of packages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wide blade sawing is used to remove dielectric layers, then the removal efficiency is improved, but the risk of penetrating the semiconductor substrate increases
Solution Approach 1:
The singulation process is divided into multiple sequential steps: first performing narrow laser grooving to create initial grooves, then performing wide blade sawing to remove dielectric layers, and finally performing additional narrow laser grooving to complete the separation. This segmentation allows each step to be optimized independently, enabling efficient dielectric removal while maintaining precise substrate penetration control through the use of multiple narrower grooves rather than a single wide cut.
2Manufacturing precision
If multiple narrow laser grooving processes are performed, then the precision of dielectric layer removal is improved, but the processing time increases
Solution Approach 1:
Multiple narrow laser grooving processes are merged with wide blade sawing operations in an alternating sequence. The narrow laser grooves are used to create precise separation paths, while the wide blade sawing efficiently removes dielectric layers between adjacent grooves. This combination allows the process to achieve the precision of multiple narrow grooves while using the faster wide blade sawing for the bulk material removal, thereby reducing total processing time.
3Reliability
If overlapping laser grooving paths are used, then the completeness of dielectric layer removal is improved, but the complexity of the process increases
Solution Approach 1:
The first set of narrow laser grooves is performed as a preliminary action to create initial separation paths and define the boundaries of dielectric layers to be removed. Subsequent wide blade sawing operations then efficiently remove the dielectric material between these pre-defined grooves. This preliminary grooving action simplifies the overall process by establishing clear boundaries before bulk removal, reducing the complexity compared to attempting complete removal in a single step.
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 approach enhances the accuracy and control of the singulation process, preventing damage to dielectric layers and ensuring the sawing process stops at the appropriate depth, thereby improving the efficiency and reliability of package separation.
Implementation Method 1
performing a first plurality of laser grooving processes on a scribe line of a substrate to form a first combined groove; performing a second plurality of laser grooving processes on the scribe line of the substrate to form a second combined groove
Implementation Method 2
performing a first sawing process on the scribe line of the substrate, wherein the first sawing process is performed in a part of the scribe line between the first combined groove and the second combined groove; performing a second sawing process to saw through the substrate in the scribe line
Data Source
AI summary
A method includes performing a first plurality of laser grooving processes on a scribe line of a wafer to form a first combined groove, and performing a second plurality of laser grooving processes on the scribe line of the wafer to form a second combined groove. A first sawing process is performed on the scribe line of the wafer. The first sawing process is performed in a part of the scribe line between the first combined groove and the second combined groove. A second sawing process is performed to saw through the wafer in the scribe line. The second sawing process separates a first device die and a second device die on opposing sides of the scribe line from each other.