Laser Module Subcarrier Recess Structure to Prevent Light Blocking
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Solution Overview
Problem
In laser diode elements, the melted AuSn solder can block laser light by sticking out and forming a structure that obstructs the irradiation surface, hindering the desired optical path for the laser light.
Innovation Solution
A subcarrier design with a recessed portion on its wafer portion, where a eutectic layer is formed, allowing the AuSn solder to solidify within the recessed area, preventing it from obstructing the laser light path and ensuring the solder does not stick to the optical semiconductor element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If melted AuSn solder is used to bond the chip to the sub-mount, then bonding strength is improved, but the solder may stick out and block laser light
Solution Approach 1:
The subcarrier is designed with a recessed portion at the specific location where the eutectic layer is formed, creating a localized containment structure. This recessed portion has specific dimensional parameters (depth of 10 μm or more, width and length dimensions) that are optimized to contain the molten solder while maintaining bonding strength. The local structural modification allows the solder to be confined to the recessed area, preventing it from protruding onto the laser irradiation surface while still achieving strong bonding between the chip and sub-mount.
2Ease of manufacture
If the eutectic layer is formed on the subcarrier surface, then bonding is achieved, but the melted solder may obstruct the optical path
Solution Approach 1:
The recessed portion is pre-formed on the subcarrier before the eutectic layer bonding process. This preliminary structural preparation ensures that when the AuSn solder is melted during bonding, it will naturally flow into and be contained within the recessed portion. The recessed portion acts as a pre-designed containment structure that guides the molten solder to the appropriate location, preventing it from obstructing the optical path while maintaining ease of manufacture through a standardized bonding process.
3Device complexity
If the chip is bonded directly to the sub-mount surface, then assembly is simplified, but laser light may be blocked by the bonding material
Solution Approach 1:
Instead of modifying the entire subcarrier structure or creating complex multi-layer bonding structures, the invention introduces a localized recessed portion only at the specific location where the eutectic layer is formed. This minimal local modification maintains the overall simplicity of the assembly structure while effectively solving the laser light blocking problem. The recessed portion is integrated into the subcarrier design, requiring no additional assembly steps or complex structures.
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 design effectively prevents the blocking of laser light by the AuSn solder, ensuring reliable laser light transmission and improving the functionality of the laser module, particularly in compact devices like XR glasses.
Implementation Method 1
a eutectic layer that is formed on the first metal layer... if the melted AuSn solder sticks out on an irradiation surface of the laser diode element, laser light is blocked by the structure of melted AuSn
Data Source
AI summary
What is provided is a subcarrier and a laser module in which, when an optical semiconductor element is formed on the subcarrier, blocking of an irradiation surface of the optical semiconductor element by a structure formed by melting is curbed.This subcarrier is a subcarrier for a laser module including a wafer portion that is constituted of a base and a protective layer formed on a surface of the base, a first metal layer that is formed on the protective layer, a eutectic layer that is formed on the first metal layer, and a second metal layer that is formed on the eutectic layer. The wafer portion has a recessed portion formed in a region overlapping the eutectic layer in a width direction, that is, a region on an outward side of the first metal layer in a longitudinal direction.