Solder Bump Intermetallic Uniformity for Void-Resistant Packaging
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Solution Overview
Problem
Existing semiconductor devices face issues with void destruction due to variations in the thickness of intermetallic compounds at the electrode interfaces, leading to microvoid generation and reduced reliability under high-temperature conditions.
Innovation Solution
The semiconductor device is designed with a solder composition that includes Sn as a main component and controls the variation in thickness of the bonding portion, an intermetallic compound, to less than 2 micrometers, and optimizes the composition by limiting Bi content to less than 3.0 wt% and incorporating Sb content of 3.0 wt% or more, thereby suppressing void destruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder joints are used to connect BGA electrodes to circuit board electrodes, then electrical connection and mechanical bonding are achieved, but void destruction and microvoid generation occur under high-temperature conditions, reducing reliability
Solution Approach 1:
The invention changes the chemical composition parameters of the solder joint by specifying precise ranges for Cu (0.6-1.2 mass%), Ag (3.0-4.0 mass%), and Bi (0.0-1.0 mass%), along with In content based on Cu content. These parameter adjustments optimize the intermetallic compound formation to suppress void destruction while maintaining bonding reliability under thermal cycling conditions.
Solution Approach 2:
The invention uses a composite solder material system containing multiple elements (Sn, Cu, Ag, Bi, In) that work synergistically. The specific composition creates a complex intermetallic compound structure (Cu6Sn5, Ag3Sn, Bi2Te3, InSn) that resists void destruction better than conventional single-element or simple alloy solders.
2Area of stationary object
If area array type packaging with solder bumps is used for size reduction and high density, then mounting area is reduced and transmission speed is improved, but the solder joints become more susceptible to void destruction under thermal stress
Solution Approach 1:
The invention adjusts the solder composition parameters to create intermetallic compounds with optimized thickness and uniformity. The specific Cu (0.6-1.2 mass%) and Ag (3.0-4.0 mass%) content ranges control the growth rate and distribution of intermetallic compounds, ensuring sufficient bonding strength for high-density mounting while resisting void destruction under thermal cycling.
Solution Approach 2:
The invention preemptively addresses void destruction by designing a solder composition that forms protective intermetallic compound layers before thermal stress occurs. The Bi and In elements create phases (Bi2Te3, InSn) that act as cushioning layers, preventing void coalescence and destruction during subsequent temperature cycling in high-density mounting applications.
3Strength
If intermetallic compound bonding portions are formed at electrode interfaces, then strong bonding is achieved, but variation in thickness of the bonding portion causes non-uniform stress distribution and microvoid generation
Solution Approach 1:
The invention precisely controls the composition parameters to regulate intermetallic compound formation kinetics. The Cu content (0.6-1.2 mass%) controls Cu6Sn5 formation rate, Ag content (3.0-4.0 mass%) controls Ag3Sn distribution, and Bi/In content regulates additional phase formation. This parameter optimization ensures uniform thickness across the bonding portion while maintaining strong 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
This configuration effectively suppresses void destruction and microvoid generation, enhancing the reliability and lifespan of the solder bumps under temperature cycling conditions.
Implementation Method 1
a solder that connects the electronic component and the board... the solder has a bonding portion that is an intermetallic compound at an interface with each of the first electrode and the second electrode
Implementation Method 2
the solder has a bonding portion that is an intermetallic compound at an interface with each of the first electrode and the second electrode
Data Source
AI summary
A semiconductor device includes an electronic component and a board that are disposed opposite to each other in a first direction, and a solder that connects the electronic component and the board, in which the electronic component includes a first electrode on a surface facing the board, the board includes a second electrode on a surface facing the electronic component, the solder has a bonding portion that is an intermetallic compound at an interface with each of the electronic component and the board, the solder contains Sn as a main component, and a variation in thickness of the bonding portion in the first direction is less than 2 micrometers.