Lead Frame Packaging Structure to Prevent PCB Cracking
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Solution Overview
Problem
Current circuit board packaging methods using plastic packaging materials are prone to cracking, leading to low safety and reliability due to the direct plastic packaging of printed circuit boards and subsequent conductive pin connections.
Innovation Solution
A lead frame packaging method involving a hollow bezel with integrally formed first and second pin parts and connecting ribs, where the circuit board is first aligned and electrically connected to the pins using a conductive agent before being plastically packaged, enhancing connection fastness and safety by cutting the pins from the lead frame after packaging, thereby improving the reliability of the electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the printed circuit board is directly plastically packaged by being covered with a plastic packaging material, then the packaging process is simple, but the plastic packaging material and the printed circuit board are prone to be cracked, causing a failure in the plastic packaging of the power circuit
Solution Approach 1:
The patent introduces a lead frame as an intermediary component between the printed circuit board and the plastic packaging material. The lead frame includes a base island with reinforcing ribs and pin groove support ribs that provide structural support during packaging. This mediator prevents direct contact between the plastic material and the circuit board, eliminating the cracking problem while maintaining packaging simplicity.
Solution Approach 2:
The lead frame is prepared in advance with reinforcing ribs and pin groove support ribs that provide preemptive structural reinforcement. These features are designed beforehand to cushion and distribute stresses during the packaging process, preventing cracks before they occur in both the plastic packaging material and the printed circuit board.
2Device complexity
If the printed circuit board is directly plastically packaged, then the packaging structure is simple, but safety and reliability are relatively low due to cracking
Solution Approach 1:
The lead frame serves as a mediator structure that improves reliability without significantly increasing overall device complexity. The base island with reinforcing ribs and pin groove support ribs provides necessary structural support, while the modular design keeps the added complexity manageable.
Solution Approach 2:
The packaging structure is segmented into distinct functional components: the lead frame with base island, reinforcing ribs, and pin groove support ribs; the printed circuit board; and the plastic packaging material. This segmentation allows each component to perform its specific function optimally, improving overall reliability while maintaining reasonable complexity.
3Ease of manufacture
If pins are connected to conductive pads after plastic packaging by grinding and connecting, then the connection process is simple, but the connection fastness is insufficient leading to potential failures
Solution Approach 1:
The pins are pre-positioned on the lead frame base island before plastic packaging occurs. The pin groove support ribs provide preliminary support and alignment, ensuring proper positioning and strong connection fastness from the outset, rather than attempting to establish connections after packaging is complete.
Solution Approach 2:
The pin groove support ribs provide beforehand cushioning and support for the pins during the packaging process. This preemptive support ensures strong connection fastness is maintained throughout packaging and operation, preventing connection failures while keeping the overall process relatively simple.
Data Source
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AI summary
This application provides a packaging solution, such as a lead frame for circuit board packaging, a packaged integrated circuit board, a power chip, and a circuit board packaging method, to improve safety and reliability of the packaged circuit board. The lead frame includes a plurality of frame units disposed in parallel in a first direction. The frame unit includes a hollow bezel, and a plurality of pins and connecting ribs that are disposed in the bezel. Each pin includes a first pin part and a second pin part that extend in a second direction and are integrally formed. The first pin part is disposed in the bezel, the first pin part is configured to electrically connect to a circuit board, and the second pin part is connected and fastened to the bezel. The second direction is perpendicular to the first direction. The connecting ribs are connected among the plurality of pins and the bezel.