Chip-on-Submount Structure With Distortion Suppression Layer

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The challenge in manufacturing a semiconductor laser chip is to reduce size without causing output power reduction and to prevent distortions that can occur in the chip, which can lead to the destabilization of the radial shape of laser light emitted from the semiconductor laser.

Innovation Solution

A chip-on-submount structure is designed with a broad area type chip that includes an active layer and a current injection stripe, a distortion suppression layer made of metal, a submount with a substrate and electrode layer, and a solder layer interposed between the distortion suppression layer and the electrode layer, where the distortion suppression layer includes a reaction layer and an unreacted layer with a thickness of not less than 1.4 µm.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the width of the chip is decreased to reduce chip size and manufacturing cost, then chip size is reduced, but the degree of difficulty in manufacturing chip-on-submount structure increases and distortion occurs in the chip

Engineering Contradiction:
Improvechip sizeVSAvoidmanufacturing difficulty
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

A distortion suppression layer is introduced as an intermediary component between the chip and submount. This layer, made of metal with appropriate thickness, acts as a mediator that absorbs and distributes mechanical stress during the chip-on-submount manufacturing process, thereby reducing manufacturing difficulty and preventing chip distortion even when chip width is reduced.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The distortion suppression layer is constructed as a composite structure with multiple layers having different material properties. This composite design allows the structure to simultaneously provide mechanical support, stress distribution, and thermal management functions, enabling reduced chip size while maintaining manufacturability.

Inventive Principle:
Principle #40Composite materials

2Volume of moving object

If the width of the chip is decreased to reduce chip size, then chip size is reduced, but distortion occurs in the chip leading to destabilization of laser light radial shape

Engineering Contradiction:
Improvechip sizeVSAvoidlaser light radial shape stability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The distortion suppression layer serves as a protective intermediary that isolates the chip from mechanical stresses during mounting and operation. This layer prevents distortion of the chip structure, thereby maintaining the stability of the laser light radial shape even when chip dimensions are reduced.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The distortion suppression layer is designed with sufficient thickness beforehand to cushion and absorb mechanical stresses that would otherwise cause chip distortion. This pre-engineered cushioning capability ensures that the chip maintains its structural integrity and laser beam quality under various operating conditions.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Power

If the current injection stripe width is increased to achieve high output power, then output power exceeds 10 W, but chip size increases

Engineering Contradiction:
Improveoutput powerVSAvoidchip size
Core Design Contradiction:
PowerVSVolume of moving object

Solution Approach 1:

The invention optimizes the parameters of the distortion suppression layer, including its thickness and material composition, to enable the use of wider current injection stripes for high power output while maintaining compact chip dimensions. The layer's mechanical properties are specifically tuned to support high-power current injection without causing chip distortion.

Inventive Principle:
Principle #35Parameter changes

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 structure effectively suppresses distortions in the semiconductor laser chip, ensuring stable emission of laser light, thereby enhancing the stability of the radial shape of laser light emitted.

Implementation Method 1

a configuration is employed in which the distortion suppression layer includes a reaction layer, in which a component of the solder layer is diffused, and an unreacted layer, in which the component of the solder layer is not diffused

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP4668504A1Chip-on-submount structure
Publication Date: 2025.12.24 FUJIKURA LTD
  • EP4668504A1 patent drawingFigure 1
  • EP4668504A1 patent drawingFigure 2
  • EP4668504A1 patent drawingFigure 3(a)~3(b)

AI summary

Provided is a chip-on-submount structure that is capable of suppressing distortions which can occur in a chip of a semiconductor laser. A chip-on-submount structure (1) includes: a chip (10) that includes a current injection stripe (161) which injects a current into an active layer (13); a distortion suppression layer (20) that covers the current injection stripe (161) and that is made of a metal; a submount (40) that includes an electrode layer (electrode pattern 42); and a solder layer (30) that is interposed between the distortion suppression layer (20) and the electrode layer (electrode pattern 42). In the distortion suppression layer (20), an unreacted layer (201) in which a component of the solder layer (30) is not diffused has a thickness of not less than 1.4 µm.