Semiconductor Laser Device Bonding via Solder Ball Alignment
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Solution Overview
Problem
Existing methods for bonding a light-transmissive member and a package in semiconductor device manufacturing face challenges in achieving high alignment accuracy, particularly when performed in a vacuum chamber, as moisture or gas can remain on the surfaces, leading to misalignment and reduced bonding precision.
Innovation Solution
A method involving the formation of solder balls on the package or light-transmissive member, pre-securing by aligning and softening the solder balls, and then reducing pressure to inject sealing gas before heating and pressing to melt the solder balls, ensuring high alignment accuracy without the need for a vacuum chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If bonding is performed in a vacuum chamber, then moisture and gas are removed from surfaces, but alignment accuracy deteriorates due to difficulty in bonding with high precision in vacuum environment
Solution Approach 1:
The patent applies preliminary action by forming solder balls on the bonding surface before the bonding process. These pre-formed solder balls serve as alignment references and bonding mediators, allowing the light-transmissive member to be accurately positioned and bonded to the package without requiring vacuum chamber conditions. This preliminary preparation enables high alignment accuracy while avoiding the harmful effects of moisture and gas.
2Manufacturing precision
If bonding is performed in substituted gas instead of vacuum, then alignment accuracy improves, but moisture and gas remain on the surface
Solution Approach 1:
The patent applies parameter changes by utilizing the melting and solidification properties of solder material. The bonding process involves heating to melt the solder balls, allowing them to flow and form strong bonds, then cooling to solidify them. This phase change enables effective bonding in a substituted gas environment without requiring vacuum conditions, while the solder itself displaces the harmful moisture and gas at the bonding interface.
3Strength
If solder balls are formed closely, then bonding strength improves, but air passage for pressure reduction and gas injection is blocked
Solution Approach 1:
The patent applies local quality by creating non-uniform spacing of solder balls. Some regions have closely spaced solder balls to provide strong bonding, while other regions have sparsely spaced or larger spaced solder balls to maintain air passages. This local variation in solder ball distribution allows simultaneous achievement of high bonding strength in critical areas and adequate gas flow paths in other areas, resolving the contradiction between bonding strength and productivity.
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 allows for the precise bonding of light-transmissive and package components with high alignment accuracy, reducing the risk of misalignment and moisture-related issues, while enabling hermetic sealing of semiconductor devices at a lower cost compared to traditional vacuum-based methods.
Implementation Method 1
heating and pressing the light-transmissive member and the package, to melt the solder balls and bond the light-transmissive member and the package
Implementation Method 2
a bonding step of reducing a pressure in the recess via the air passage, and thereafter, in the state in which a gas for sealing is injected
Data Source
AI summary
A semiconductor laser device includes: a package includes a recess and an upper surface that has an outer peripheral surface and a bonding surface positioned between the recess and the outer peripheral surface, the bonding surface having inner corners on the recess side and outer corners on the outer peripheral surface side; at least one semiconductor laser element disposed in the recess of the package; and a light-transmissive member bonded to the bonding surface of the package. The radius of curvature of inner corners is greater than the radius of curvature of outer corners.