Oblique Optical Waveguide End Surfaces via Stealth Dicing
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Solution Overview
Problem
Conventional methods for producing optical waveguides with oblique end surfaces to reduce back reflections are inefficient, requiring a two-step process of dicing and polishing, which is time-consuming and costly, and often result in inconsistent optical quality.
Innovation Solution
The method involves using stealth dicing laser processing to create defect regions in a semiconductor wafer along oblique cutting lines, inducing fractures to produce angled end surfaces without the need for polishing, ensuring optical quality and reducing microcracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a two-step process of dicing and polishing is used to produce oblique end surfaces, then optical quality is improved, but manufacturing complexity and time increase
Solution Approach 1:
The patent combines dicing and polishing operations into a single integrated process. The polishing step is performed in-situ during the dicing operation, eliminating the need for separate polishing equipment and processing steps while maintaining optical quality of the end surfaces.
Solution Approach 2:
The polishing action is performed preliminarily during the dicing process itself, before the wafer is fully separated. This preliminary polishing prepares the end surfaces for optimal optical performance while the wafer is still held in the dicing apparatus, reducing subsequent processing requirements.
2Shape
If conventional dicing and polishing is used, then oblique end surfaces are produced, but production time and cost increase
Solution Approach 1:
The dicing and polishing operations are merged into a single simultaneous process. The polishing head is integrated into the dicing apparatus and operates concurrently with the cutting blade, producing oblique end surfaces at the same rate as dicing without requiring separate polishing cycles.
Solution Approach 2:
The polishing action continues continuously throughout the dicing process. As the cutting blade progresses through the wafer, the polishing head continuously acts on the emerging end surfaces, ensuring that polishing is never interrupted and maintaining constant production flow without idle time.
3Manufacturing precision
If multiple processing steps are used, then optical quality can be achieved, but microcracks and defects increase
Solution Approach 1:
The polishing action is applied preliminarily during dicing while the wafer is still supported and stable. This preliminary polishing removes stresses and defects at the moment of cutting without subjecting the material to additional handling and re-fixturing that could induce microcracks.
Solution Approach 2:
The integrated process rushes through the critical transition phase of wafer separation in a single continuous operation. By completing both dicing and polishing in one uninterrupted sequence, the material is not subjected to multiple handling cycles that could create stress concentrations and microcracks.
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 effectively produces optical waveguides with angled end surfaces that minimize back reflections, reducing return losses and achieving consistent optical quality without the need for costly polishing steps.
Implementation Method 1
Stealth dicing laser processing is applied to the semiconductor wafer by producing defect regions into the wafer along at least one cutting line
Implementation Method 2
The wafer is expanded to induce fracture thereof at the at least one cutting line
Data Source
AI summary
A method includes providing a semiconductor wafer that includes at least one optical waveguide extending in a longitudinal direction. Stealth dicing laser processing is applied to the semiconductor wafer by producing defect regions into the wafer along at least one cutting line. The cutting line is oblique to the longitudinal direction of the at least one optical waveguide. The wafer is expanded to induce fracture thereof at the at least one cutting line, thereby producing an end surface of the at least one optical waveguide. The end surface is oblique to the longitudinal direction of the at least one optical waveguide.