Nitride Semiconductor UV LED Base with Fluororesin Solder Resist
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Solution Overview
Problem
The degradation of silicone resin and epoxy resin-based solder resist materials under high energy ultraviolet light leads to short-circuits in nitride semiconductor ultraviolet light-emitting elements, particularly due to metal atom migration, which compromises the reliability and efficiency of ultraviolet light-emitting devices.
Innovation Solution
A base with insulating material and gold or platinum group metal films, where the exposed surfaces are covered with a fluororesin film to prevent solder material adherence and migration, ensuring high ultraviolet resistance and reducing the likelihood of short-circuits between metal wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silicone resin or epoxy resin-based solder resist materials are used to prevent short-circuits, then ease of manufacture is improved, but reliability deteriorates under high energy ultraviolet light due to material degradation and metal atom migration
Solution Approach 1:
The patent changes the material parameter from conventional silicone or epoxy resin to fluororesin, which has superior ultraviolet resistance. This parameter change resolves the contradiction by maintaining ease of manufacture through similar application processes while dramatically improving reliability under high energy ultraviolet light exposure, preventing both material degradation and metal atom migration.
Solution Approach 2:
The patent employs fluororesin as a specialized composite material that combines ultraviolet resistance with solder resist functionality. This composite material approach allows the solder resist layer to simultaneously withstand high energy ultraviolet light and prevent short-circuits, resolving the contradiction between conventional material ease of manufacture and ultraviolet-induced reliability failures.
2Device complexity
If conventional solder resist materials are used, then manufacturing process simplicity is improved, but object-generated harmful factors worsen due to metal atom migration causing short-circuits
Solution Approach 1:
The patent changes the chemical composition parameter of the solder resist material to fluororesin, which fundamentally alters the material's interaction with ultraviolet light and metal atoms. This parameter change maintains device complexity at an acceptable level while eliminating the harmful effect of metal atom migration that occurs with conventional materials under ultraviolet exposure.
Solution Approach 2:
The patent converts the potential harm of ultraviolet light exposure into a beneficial effect by using fluororesin that is specifically designed to resist ultraviolet degradation. The material's ultraviolet resistance property, which might seem like an over-specification, actually prevents the harmful metal atom migration, turning a potential failure mode into a reliability advantage.
3Reliability
If fluororesin film is applied to cover exposed surfaces, then reliability is improved by preventing solder material migration, but device complexity increases
Solution Approach 1:
The patent applies fluororesin that serves multiple functions simultaneously: it acts as a solder resist material preventing short-circuits, provides ultraviolet resistance against high energy light degradation, and maintains ease of manufacture through standard coating processes. This multi-functionality resolves the contradiction by achieving improved reliability without proportionally increasing device complexity.
Solution Approach 2:
The patent changes the material parameter to fluororesin with specific properties including ultraviolet resistance and solder resist functionality. This parameter change enables a single material to perform multiple protective functions, improving reliability while keeping the overall device structure and manufacturing process relatively simple.
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 solution effectively prevents short-circuits and maintains high reliability of ultraviolet light-emitting devices by using fluororesin films to inhibit solder material migration and adherence, even under high energy ultraviolet exposure.
Implementation Method 1
the exposed surfaces are covered with a fluororesin film to prevent solder material adherence and migration
Implementation Method 2
A base with insulating material and gold or platinum group metal films, where the exposed surfaces are covered with a fluororesin film to prevent solder material adherence and migration, ensuring high ultraviolet resistance
Data Source
AI summary
To prevent degradation of electrical characteristics caused by a resin filled between electrodes in an ultraviolet light-emitting operation, the present invention provides a base 10 that comprises an insulating base material 11 and two or more metal films 12 and 13 that are formed on one side of the insulating base material 11 and electrically separated from each other. The two or more metal films are formed to include an upper surface and a side wall surface that are covered by gold or a platinum group metal, to be capable of mounting thereon one or more nitride semiconductor light-emitting elements and the like, and to have, as a whole, a predetermined planar view shape including two or more electrode pads. On the one side of the base material 11, along a boundary line between an exposed surface of the base material 11 that is not covered by the metal film 12, 13 and a side wall surface of the metal film 12, 13, at least a first part of the exposed surface of the base material 11 continuous with the boundary line that is sandwiched between two adjacent electrode pads and the side wall surfaces of the metal films 12 and 13 that oppose to each other with the first part interposed therebetween are covered by a fluororesin film 16, and a part of an upper surface of the metal film 12, 13 that composes at least the electrode pad is not covered by the fluororesin film 16.