Capacitor Mounting Structure Using Cu Solder to Suppress Ni-Sn Alloy Growth
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Solution Overview
Problem
The alloy formed by the Ni component in the external electrode and the Sn component in the solder grows thick due to high heat, leading to a decrease in bonding strength between the electronic component and the substrate, which is brittle and hard.
Innovation Solution
Incorporating Cu particles into the solder, which are distributed between the external electrode and the land, preventing the growth of the Ni-Sn alloy and maintaining bonding strength by ensuring the solder thickness under the product electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the Ni-Sn alloy is allowed to grow thick due to high heat exposure, then the bonding area increases, but the bonding strength decreases because the alloy becomes hard and brittle
Solution Approach 1:
The patent changes the chemical composition parameters of the solder by adding Cu particles (0.01-10 wt%). This compositional modification alters the alloying behavior during heating, preventing excessive Ni-Sn alloy layer growth while maintaining adequate bonding area, thus resolving the contradiction between bonding area and bonding strength
Solution Approach 2:
The patent creates a composite solder material consisting of Sn-based solder matrix with dispersed Cu particles. This composite structure modifies the intermetallic compound formation characteristics, suppressing the growth of brittle Ni-Sn alloy layers while preserving bonding effectiveness, thereby simultaneously achieving adequate bonding area and high bonding strength
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 Cu particles effectively suppress the growth of the brittle Ni-Sn alloy, enhancing bonding reliability and maintaining the integrity of the electronic component to the substrate.
Implementation Method 1
The solder contains particles including Cu, and has a portion protruding outward with respect to an outer edge of the electronic component when viewed in a direction orthogonal to the substrate, and the particles are located between the external electrode and the land and in the protruding portion
Data Source
AI summary
In the mounting structure of an electronic component, an alloy having a Ni component included in each external electrode and the land of the substrate and a Sn component included in the solder is generated in the production process. A mounting structure of an electronic component includes a substrate having a land, a capacitor component having a first external electrode stacked on an outer surface of a base body, and a solder including Sn. At least one of the first external electrode and the land contains Ni. The first external electrode is bonded to the land with the solder. The solder contains the Cu-containing particles, and has a portion protruding outward with respect to the outer edge of the capacitor component when viewed from a direction orthogonal to the substrate. The particles are located between the first external electrode and the land and in the protruding portion.