Lead Frame Columnar Electrode Plating for Solder Connection
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Solution Overview
Problem
The existing manufacturing methods for lead frames result in inefficient production due to excessive etching time and inadequate contact area between terminal portions and solder, leading to poor connection strength with mount boards.
Innovation Solution
A lead frame design featuring columnar electrodes with a metal plating layer on the lower surface and side surfaces, which reduces etching time and enhances solder contact by forming the metal plating layer on both surfaces of the electrodes, thereby improving connection strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the copper plate is wet-etched from the lower surface side to separate the die pad portion and terminal portions, then the terminal portions are individually separated, but the etching amount is large which extends processing time and reduces production efficiency
Solution Approach 1:
A metal plating layer is formed on the lower surface and side surfaces of the electrode before the wet-etching process. This preliminary plating action creates a protective mask that enables selective etching, allowing the copper plate to be separated into individual terminal portions without requiring excessive etching depth, thereby reducing processing time while maintaining separation precision
Solution Approach 2:
The metal plating layer serves as an intermediary substance between the etching solution and the copper electrode. It acts as a protective barrier that prevents the etching solution from attacking the copper, enabling precise control over the etching process and allowing for shorter etching times while achieving the required separation
2Area of stationary object
If the pitch between adjacent terminal portions is narrowed to reduce the area of lower surfaces, then the area of each terminal portion is reduced, but the contact area with solder becomes smaller which reduces connection strength
Solution Approach 1:
The metal plating layer extends onto the side surfaces of the columnar electrodes, utilizing the vertical dimension to increase the solder contact area. This dimensional extension allows the terminal portions to maintain narrow pitch while compensating for reduced lower surface area through additional side surface contact, thereby preserving connection strength
Solution Approach 2:
The metal plating layer is selectively applied to specific regions - the lower surface and side surfaces of the electrodes - creating areas with different properties. The side surface plating provides enhanced local contact zones for solder attachment, compensating for the reduced overall terminal area and maintaining connection strength despite narrow pitch
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 proposed solution reduces etching time, increases contact area between terminal portions and solder, and enhances the reliability of electronic component devices by improving connection strength with mount boards.
Implementation Method 1
a metal plating layer, wherein the metal plating layer is formed on a lower surface of the electrode and a portion of a side surface of the electrode
Data Source
AI summary
An electronic component device, includes: a lead frame including a terminal portion, the terminal portion including a columnar electrode and a metal plating layer, wherein the metal plating layer is formed on a lower surface of the electrode and a portion of a side surface of the electrode; an electronic component mounted on the lead frame to be electrically connected to the terminal portion; and a sealing resin that seals the lead frame and the electronic component, wherein another portion of the side surface of the electrode is embedded in the sealing resin and the metal plating layer is exposed from the sealing resin.