Laser Diode Alignment Using 3D Edge Marks for EAMR Heads
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Solution Overview
Problem
Conventional methods for aligning substrates in EAMR disk drives, particularly those with edge-emitting lasers, face challenges due to the difficulty in using two-dimensional alignment marks on the edge of the substrate, making precise alignment difficult and inefficient.
Innovation Solution
The method involves forming alignment marks on the surface of the substrate that extend through portions where edges will form, allowing for alignment using marks visible from the edge for the laser diode and marks on the side edge for the waveguide, facilitating precise alignment through photolithographic processes and etching techniques, and using these marks to align the laser diode with the waveguide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional two-dimensional alignment marks are used on the edge of the substrate for edge-emitting laser alignment, then the alignment process can be performed, but the manufacturing precision and ease of manufacture deteriorate due to difficulty in fabricating and using such marks
Solution Approach 1:
The patent transitions from conventional two-dimensional alignment marks to three-dimensional alignment marks that extend through portions of the substrate thickness. These 3D marks are formed by etching grooves or depositing material that creates visible features on the edge surface of the substrate, enabling precise alignment in the third dimension while maintaining ease of manufacture through standard photolithographic and etching processes.
2Reliability
If the laser diode substrate is oriented perpendicular to the conventional configuration to position the emission edge closest to the slider, then the optical coupling may be improved, but the alignment difficulty increases significantly
Solution Approach 1:
The patent introduces alignment marks as intermediary features that mediate between the laser diode emission edge and the waveguide input. These marks serve as reference points that simplify the alignment process by providing visible, easily detectable features that guide the positioning process, thereby reducing the overall complexity of aligning the substrates in the perpendicular orientation.
Data Source
AI summary
A method and system align a laser diode on a first substrate to a waveguide on a second substrate. The first substrate includes an edge and a first surface adjoining the edge. The laser diode has an emission exit on the edge. The second substrate includes a back side and a side edge. The waveguide has a waveguide input on the back side and directs light along the side edge. A first alignment mark set on the first substrate is aligned to a second alignment mark set on the second substrate. The first alignment mark set corresponds to the emission exit, is formed on the first surface and is visible from the edge. The second alignment mark set corresponds to the waveguide input, is formed on the side edge, and is visible from the back side. The first substrate's edge is affixed to the second substrate's back side.