Triangular Metal-Plated Bond Area for Leadframe Solder Creepage
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Solution Overview
Problem
In semiconductor die packaging, the placement of a metal-plated bond area on a leadframe poses a challenge as it needs to be close to the semiconductor die for minimal size increase, but its proximity can interfere with the die attach process and lead to solder creepage issues.
Innovation Solution
A semiconductor package design featuring a leadframe with a carrier section where the semiconductor die is solder-bonded, and a metal-plated bond area with a substantially triangular shape is provided on the carrier section, using a different metal than the leadframe, and an electrical conductor is connected to the die pad and bonded to this area, with optional obstacles for solder creepage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the metal-plated bond area is placed close to the semiconductor die to minimize leadframe size increase, then the leadframe size is kept small, but it may interfere with the die attach process and cause solder creepage issues
Solution Approach 1:
The patent applies local quality by providing a metal-plated bond area with a specific metal coating (different from the leadframe base metal) only in the localized region where bonding is required, rather than plating the entire leadframe. This localized metal plating (e.g., with solder wetting enhancement) improves bonding reliability at the specific location without requiring the entire leadframe to be larger or fully plated, thus resolving the contradiction between minimizing leadframe size and ensuring reliable die attach.
2Area of stationary object
If the metal-plated bond area is placed close to the semiconductor die, then the leadframe size increase is minimized, but solder creepage may occur during the die attach process
Solution Approach 1:
The patent applies local quality by providing a metal-plated bond area with a specific metal coating (different from the leadframe base metal) only in the localized region where bonding is required, rather than plating the entire leadframe. This localized metal plating (e.g., with solder wetting enhancement) improves bonding reliability at the specific location without requiring the entire leadframe to be larger or fully plated, thus resolving the contradiction between minimizing leadframe size and ensuring reliable die attach.
3Reliability
If a metal-plated bond area is provided on the carrier section, then reliable bonding is achieved, but the size of the leadframe increases
Solution Approach 1:
The patent applies local quality by providing a metal-plated bond area with a specific metal coating (different from the leadframe base metal) only in the localized region where bonding is required, rather than plating the entire leadframe. This localized metal plating (e.g., with solder wetting enhancement) improves bonding reliability at the specific location without requiring the entire leadframe to be larger or fully plated, thus resolving the contradiction between minimizing leadframe size and ensuring reliable die attach.
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 design minimizes the size increase of the leadframe while reducing interference with the die attach process, effectively managing solder creepage and ensuring reliable bonding, thus enhancing the electrical and thermal performance of the semiconductor device.
Implementation Method 1
A leadframe comprises a carrier section on which the semiconductor die is mounted, wherein the semiconductor die is solder-bonded to the carrier section
Implementation Method 2
An electrical conductor is connected to the die pad and bonded to the metal-plated bond area
Data Source
Figure 1~3
Figure 4A~5
Figure 6~8
AI summary
A semiconductor package comprises a semiconductor die having a first surface and a second surface opposite the first surface. A die pad is disposed at the first surface of the semiconductor die. A leadframe comprises a carrier section on which the semiconductor die is mounted, wherein the semiconductor die is solder-bonded to the carrier section with the second surface facing the carrier section. A metal-plated bond area is provided on the carrier section of the leadframe, wherein a metal of the metal-plated bond area is different from a metal of the leadframe. An electrical conductor is connected to the die pad and bonded to the metal-plated bond area. The metal-pated bond area has a substantially triangular shape.