Interferometric Waveguide Grating Coupling for HAMR Laser Bonding

Solution Overview

Problem

Conventional heat-assisted magnetic recording (HAMR) disk drives face challenges in the laser bonding process, which is time-consuming and prone to alignment issues, affecting throughput and yield in the fabrication of HAMR transducers.

Innovation Solution

The use of a tapered interferometric waveguide with a coupling grating and a near-field transducer that employs surface plasmons to focus light onto the recording medium, allowing for wafer-level bonding of the laser to the slider, thereby simplifying alignment and improving fabrication efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional laser bonding is used to bond the laser to the back of the slider, then the laser can be bonded to the slider, but the bonding process takes a significant amount of time and has alignment issues between the laser and waveguide entrance

Engineering Contradiction:

Improvebonding reliabilityVSAvoidfabrication throughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The waveguide is pre-formed with an optimized entrance geometry and positioning features that enable automatic alignment during bonding. The waveguide entrance is designed with specific dimensional tolerances and spatial relationships to the laser mounting structure, allowing the laser to be bonded without time-consuming manual alignment procedures.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

An alignment mark or positioning feature is introduced as an intermediary element between the laser mounting structure and the waveguide entrance. This intermediary feature enables automatic optical alignment during the bonding process, eliminating manual alignment operations and improving both reliability and productivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If conventional laser bonding is used, then the laser can be bonded to the slider, but alignment issues between the laser and waveguide entrance occur

Engineering Contradiction:

Improvebonding reliabilityVSAvoidalignment precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The waveguide is pre-formed with an optimized entrance geometry and positioning features that enable automatic alignment during bonding. The waveguide entrance is designed with specific dimensional tolerances and spatial relationships to the laser mounting structure, allowing the laser to be bonded without time-consuming manual alignment procedures.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

An alignment mark or positioning feature is introduced as an intermediary element between the laser mounting structure and the waveguide entrance. This intermediary feature enables automatic optical alignment during the bonding process, eliminating manual alignment operations and improving both reliability and productivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If the laser is bonded to a different substrate first, then the laser can be mounted, but the bonding process becomes more complex and time-consuming

Engineering Contradiction:

Improvemounting easeVSAvoidfabrication complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The laser mounting structure is merged with the slider substrate, eliminating the need for a separate intermediate substrate. The laser is mounted directly to the slider using a simplified bonding process that integrates mounting and bonding operations, reducing fabrication complexity while maintaining ease of manufacture.

Inventive Principle:

Principle #5Merging (Combining)

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 fabrication throughput and yield of HAMR transducers by allowing looser alignment tolerances and enabling the use of different geometries, leading to improved performance and stability of the HAMR disk drive.

Implementation Method 1

The waveguide 40 is butt-coupled to the laser 20

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

The NFT 32 utilizes resonances in surface plasmons to couple light into the media 12 at a spot size smaller than the optical diffraction limit

Methodology Applied

Scientific EffectSurface plasmons:

Implementation Method 3

The NFT 32 utilizes resonances in surface plasmons

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 4

tapered interferometric waveguide

Methodology Applied

Scientific EffectInterference: Interference

Data Source

PatentUS8923102B1Optical grating coupling for interferometric waveguides in heat assisted magnetic recording heads

Publication Date: 2014.12.30 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

A heat-assisted magnetic recording (HAMR) transducer is coupled with a laser for providing energy and has an air-bearing surface (ABS) configured to reside in proximity to a media during use. The HAMR transducer includes a write pole, at least one coil, a waveguide optically coupled with the laser and a grating. The write pole is configured to write to a region of the media. The coil(s) energize the write pole. The waveguide includes arms that have an optical path difference. The grating is optically coupled with the laser. The waveguide is optically coupled with the grating and receives light from the grating.