Series Diode Package Using Modified Lead Frame
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current electronics packaging methods for high voltage power rectifiers are complex and costly, requiring multiple components and steps, which hinder performance and increase device size, while seeking to minimize manufacturing costs and complexity.
Innovation Solution
A modified lead frame with grooves or raised bosses is used to mount semiconductor diodes in series, eliminating the need for ceramic isolation boards and wire bonding, utilizing the lead frame's conductivity for electrical connection, and optionally using passivation layers to isolate non-active areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic isolation board and wire bonding are used to connect two diodes in series, then electrical isolation and connection are achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent removes the ceramic isolation board from the package structure, replacing it with a plastic encapsulant that provides both mechanical support and electrical isolation. This extraction of the ceramic component simplifies manufacturing while maintaining the necessary electrical isolation between the two diodes in series connection.
Solution Approach 2:
The plastic encapsulant serves multiple functions: it provides mechanical support for the diodes, acts as an electrical insulator between the diodes, and enables series connection through its conductive adhesive material. This multi-functional approach replaces the traditional separate ceramic isolation board and wire bonding structure.
2Reliability
If ceramic isolation board is used for series connection, then electrical isolation is provided, but manufacturing cost increases
Solution Approach 1:
The patent replaces the expensive ceramic isolation board with a cost-effective plastic encapsulant containing conductive adhesive material. This substitution significantly reduces material costs while maintaining the electrical isolation function, making the series connection approach economically viable for mass production.
Solution Approach 2:
The plastic encapsulant is formulated as a composite material combining plastic matrix with conductive adhesive particles. This composite structure provides both the electrical insulation properties of plastic and the conductive pathways needed for series connection, achieving performance at lower cost than traditional ceramic solutions.
3Reliability
If traditional series connection method is used, then electrical connection is achieved, but device size increases
Solution Approach 1:
The patent merges the electrical connection function with the structural encapsulant by incorporating conductive adhesive material directly into the plastic encapsulant. This integration eliminates the need for separate wire bonding and ceramic isolation board, reducing the overall package volume while maintaining reliable series connection between diodes.
Solution Approach 2:
The conductive adhesive material is nested within the plastic encapsulant matrix, creating a hierarchical structure where the conductive particles are embedded in the insulating plastic. This nested configuration enables electrical connection pathways to be formed within the encapsulant itself, minimizing the space required for series connection.
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 reduces manufacturing complexity and cost, enhances electrical performance, and miniaturizes devices by simplifying the assembly process and eliminating unnecessary components, thereby improving switching speed and power dissipation.
Implementation Method 1
The lead frame includes a die paddle to which one or more die is/are attached or mounted and leads which serve as the means for external electrical connection
Implementation Method 2
The lead frame includes a die paddle to which one or more die is/are attached or mounted and leads which serve as the means for external electrical connection. All parts of lead frame 30 are made of highly electrically conductive material.
Implementation Method 3
A modified lead frame with grooves or raised bosses is used to mount semiconductor diodes in series
Implementation Method 4
optionally using passivation layers to isolate non-active areas
Data Source
AI summary
An apparatus and method for a two semiconductor device package where the semiconductor devices are connected in electrical series. The first device is mounted P-side down on an electrically conductive substrate. Non-active area on the P side is isolated from the electrically conductive substrate. The second device is mounted P-side up at a spaced apart location on the substrate. Opposite sides of each are electrically connected to leads to complete the series connection of the two devices. A method of manufacturing such a package includes providing an electrically conductive lead frame, mounting one device P-side up and flipping the other device and mounting it P-side down on the lead frame with non-active area of the P side isolated from the lead frame, and connecting the other side of each device to separate leads. Isolation of the non-active area of the P side of the device can be through modification of the substrate or lead frame surface by grooves or raised portions. Alternatively, it can be by adding an electrically isolating coating on the non-active area of the P-side of a semiconductor device to allow it to be mounted P side down on an electrically conductive substrate or mounting location without modification to the substrate or lead frame.