Semiconductor Laser Ridge Structure for Solder Short-Circuit Prevention

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Solution Overview

Problem

The existing semiconductor laser elements with multi-emitter types face challenges in preventing electrical short-circuits due to solder flow during mounting, while also incurring increased manufacturing costs from shaping processes for forming concave portions in electrically-conductive layers.

Innovation Solution

A semiconductor laser element design featuring semiconductor layers with a ridge portion, an insulating film with openings, and an electrically-conductive layer connected through these openings, along with a sidewall structure to retain solder spread within non-light emitting regions, thereby preventing electrical short-circuits and reducing manufacturing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the number of light-emitting spots is increased in a multi-emitter type semiconductor laser element, then the power and performance are improved, but the interval between light-emitting spots becomes narrower, causing solder to flow out and contact adjacent light-emitting spots or electrodes during mounting

Engineering Contradiction:

Improveoutput powerVSAvoidelectrical insulation

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent divides the bonding structure into multiple segments: the electrically-conductive layer is segmented into a first portion (in the concave portion) and a second portion (on the light-emitting spot), and the bonding pad is segmented into a first bonding pad and a second bonding pad. This segmentation allows the solder to be contained in the concave portion while maintaining electrical connection through the segmented conductive layer, preventing solder from flowing to adjacent light-emitting spots.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary structure - the concave portion in the electrically-conductive layer - that acts as a mediator between the bonding pad and the light-emitting spot. This concave portion receives and contains the solder, preventing it from flowing out to contact adjacent light-emitting spots or electrodes, while still allowing the electrically-conductive layer to provide electrical connection.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a concave portion is formed in the electrically-conductive layer to prevent solder flow, then electrical short-circuiting is prevented, but the manufacturing cost increases due to additional shaping processes

Engineering Contradiction:

Improveelectrical insulationVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by forming the concave portion in the electrically-conductive layer before the mounting process. This pre-formed concave structure is designed to receive and contain the solder during bonding, eliminating the need for additional shaping processes after the electrically-conductive layer is formed, thereby reducing manufacturing complexity and cost.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent merges the solder containment function with the existing electrically-conductive layer structure. Instead of adding a separate component or performing additional shaping processes, the concave portion is integrated into the electrically-conductive layer itself, combining the electrical conduction and solder containment functions in a single structure.

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

The proposed solution effectively prevents inter-element electrical short-circuits by containing solder spread within non-light emitting regions and reduces manufacturing costs by eliminating the need for complex shaping processes.

Implementation Method 1

a concave portion is formed in the electrically-conductive layer to thereby create a space for storing a solder layer formed on the surface of a sub-mount electrode

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Implementation Method 2

since the sidewall can retain the spreading of the solder within the vicinity of a non-light emitting region

Methodology Applied

Scientific EffectPhysical barrier: Physical Containment

Data Source

PatentUS12308607B2Semiconductor laser element, method for manufacturing same, and semiconductor laser device

Publication Date: 2025.05.20 MITSUBISHI ELECTRIC CORP

AI summary

Provided here are: semiconductor layers comprised of an n-type cladding layer formed on a surface of an n-type GaAs substrate, active layers formed on surfaces of the n-type cladding layer, p-type cladding layers formed on surfaces of the active layers, and p-type contact layers formed on surfaces of the p-type cladding layers, the p-type cladding layers and the p-type contact layers being formed to have a ridges; insulating films covering surfaces of the semiconductor layers but having openings on surfaces of the p-type contact layer; and conductive layers connected to the p-type contact layers through the openings, the conductive layers being formed on surfaces of the insulating films to cover planar portions provided in the semiconductor layers adjacently to the ridges; wherein, together with the conductive layers, convex sidewalls are provided to be placed over portions of the planar portions at their sides nearer to the ridges.