Leadframe Carrier Encapsulation for Dense Optoelectronic Packaging
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Solution Overview
Problem
Existing optoelectronic semiconductor devices face challenges with mechanical stability, corrosion, and miniaturization due to exposed copper and thick lead frame structures, as well as limitations in precision and cost-effectiveness of alternative carriers like printed circuit boards and ceramic-based substrates.
Innovation Solution
The use of leadframe-based carriers without interconnection bars, featuring a potting body that encapsulates lead frame parts and metallizations, allowing for miniaturization and increased corrosion protection, and enabling high-density surface-mounting with flip chips and precise pad spacings below 100 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional lead frame structures with interconnection bars are used, then mechanical stability is provided, but device size increases and miniaturization is limited
Solution Approach 1:
The patent removes the interconnection bars from the lead frame structure, extracting the problematic element that prevented miniaturization while maintaining the essential carrier functions through the potting body and simplified lead frame design
Solution Approach 2:
The patent employs a potting body that encapsulates the semiconductor chip and lead frame parts, creating a compact, integrated structure that provides mechanical support without requiring thick interconnection bars, enabling device thickness reduction
2Reliability
If exposed copper structures are used in lead frames, then electrical conductivity is achieved, but corrosion and electromigration risks increase
Solution Approach 1:
The patent uses the potting body to encapsulate and protect the copper lead frame parts, converting the harmful exposure of copper to air (which causes corrosion and electromigration) into a beneficial protected state where the copper is isolated from environmental factors
Solution Approach 2:
The potting body creates an inert, protected environment around the copper lead frame structures, isolating them from oxygen and moisture that would otherwise cause corrosion and electromigration, effectively creating a protective atmosphere
3Manufacturing precision
If thick lead frame structures are used, then mechanical support is provided, but precision pad spacings below 100 μm cannot be achieved
Solution Approach 1:
The patent segments the lead frame into separate, thin parts that are individually positioned and encapsulated by the potting body, allowing for precise pad spacings to be achieved without requiring a single thick lead frame structure
Solution Approach 2:
The patent uses thin lead frame parts combined with a potting body to provide the necessary mechanical support, replacing the need for thick lead frame structures and enabling high-precision pad spacings below 100 μm
4Ease of manufacture
If alternative carriers like printed circuit boards or ceramic substrates are used, then mechanical stability is achieved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent employs a simplified lead frame structure with potting body that is more cost-effective than expensive ceramic substrates or printed circuit boards, achieving the necessary mechanical stability through clever design rather than expensive materials
Solution Approach 2:
The patent creates a composite structure combining the lead frame (metal) with the potting body (polymer or epoxy), achieving mechanical stability through material combination rather than relying on expensive single-material solutions like ceramic substrates
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 enhances mechanical stability, reduces corrosion and electromigration risks, and enables high-density packaging with improved miniaturization and corrosion protection, facilitating the use of optoelectronic semiconductor devices in applications like automotive and consumer electronics.
Implementation Method 1
The semiconductor layer sequence comprises at least one active region, which is arranged to generate radiation by means of electroluminescence during operation of the light-emitting diode chip
Data Source
AI summary
In an embodiment an optoelectronic semiconductor device includes an optoelectronic semiconductor chip configured to generate radiation and attached to a mounting side of a carrier and an encapsulation body at least partially transparent to the radiation, wherein the carrier is composed of a plurality of separate, metallic lead frame parts and of a potting body, the potting body holding the lead frame parts together, wherein the lead frame parts project beyond the potting body at the mounting side, wherein an attachment side of the carrier is opposite the mounting side so that the mounting side is further away from the attachment side than sides of the potting body facing away from the attachment side, wherein, as seen in a plan view of the attachment side, the potting body projects over the lead frame parts on all sides.