Ag3Sn Intermetallic Bonding Layer for Semiconductor Packages
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Solution Overview
Problem
Current semiconductor device packages face challenges with low re-melting temperature of bonding layers, high pressure damage during manufacturing, and poor thermal conductivity, leading to reliability and heat dissipation issues, as well as increased costs and complexity in manufacturing.
Innovation Solution
A semiconductor device package is developed with a bonding layer composed primarily of Ag3Sn, formed through a pressure-less process using a mixed paste of sinterable metal particles and solder material, which reacts to create an intermetallic compound with a high re-melting temperature and improved thermal conductivity, reducing the need for high-pressure application and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a relatively high pressure process is used in forming the bonding layer, then bonding strength is improved, but the power device and substrate may be damaged due to applied pressure, causing increase of failure rate and deterioration of reliability
Solution Approach 1:
The patent replaces the conventional high-pressure mechanical bonding process with a pressure-less sintering process. The bonding layer is formed by sintering metal particles at elevated temperatures without applying high pressure, thereby achieving strong bonding while avoiding damage to the power device and substrate.
Solution Approach 2:
The patent changes the bonding process parameters from high pressure and moderate temperature to pressure-less conditions with elevated temperature sintering. This parameter transformation allows the formation of a dense, strong bonding layer without the harmful effects of high pressure on the device and substrate.
2Ease of manufacture
If the re-melting temperature of bonding layer is relatively low, then ease of manufacture is improved, but thermo-mechanical reliability and long-time reliability are deteriorated and restrictions on use temperature occur
Solution Approach 1:
The patent employs a composite bonding layer consisting of metal particles (such as Cu, Ag, Al) and solder material. This composite structure combines the advantages of both materials: the metal particles provide high strength and high re-melting temperature, while the solder material facilitates bonding at moderate temperatures, thereby achieving both ease of manufacture and high thermo-mechanical reliability.
Solution Approach 2:
The patent changes the re-melting temperature parameter of the bonding layer by using materials with higher melting points (such as Cu-Sn, Ag-Sn intermetallic compounds) while maintaining manufacturability through controlled sintering processes that occur at temperatures below the re-melting point of the bonding layer.
3Quantity of substance
If the thermal conductivity of bonding layer is relatively low, then cost is reduced, but it is difficult to secure desired heat dissipation characteristics
Solution Approach 1:
The patent uses a composite bonding layer with metal particles (such as Cu, Ag) that have high thermal conductivity combined with solder material. This composite structure provides excellent heat dissipation characteristics while controlling material costs through optimized composition ratios and selection of cost-effective metal particles.
Solution Approach 2:
The patent optimizes the thermal conductivity parameter of the bonding layer by adjusting the composition, particle size distribution, and density of metal particles within the bonding layer, thereby achieving desired heat dissipation characteristics without excessive material cost.
4Ease of manufacture
If the bonding layer includes pores or cavities, then ease of manufacture is improved, but these may act as crack initiation site or crack propagation path, causing deterioration of long-time reliability
Solution Approach 1:
The patent replaces the conventional pressure-based bonding method with a pressure-less sintering process that uses elevated temperature to densify the bonding layer. This substitution eliminates the formation of pores and cavities that would otherwise be created or exacerbated by high-pressure mechanical bonding, thereby improving long-time reliability by preventing crack initiation and propagation.
Solution Approach 2:
The patent utilizes the phase transition of the solder material from solid to liquid and back to solid during the sintering process to fill voids and pores, creating a dense bonding layer structure that is free from defects that could serve as crack initiation sites.
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 solution provides semiconductor device packages with enhanced strength, reliability, and thermal conductivity, while simplifying the manufacturing process and reducing costs by eliminating the need for high-pressure processes and using a high-re-melting temperature bonding layer, thus improving long-time and thermo-mechanical reliability.
Implementation Method 1
heating the mixed paste is performed to sinter the metal particles
Implementation Method 2
form an intermetallic compound by reaction between the metal particles and the solder material
Data Source
AI summary
Semiconductor device packages and methods of manufacturing the semiconductor device packages are provided. A semiconductor device package may include a bonding layer between a substrate and a semiconductor chip, and the bonding layer may include an intermetallic compound. The intermetallic compound may be a compound of metal and solder material. The intermetallic compound may include Ag3Sn. A method of manufacturing the semiconductor device package may include forming a bonding layer, which bonds a semiconductor chip to a substrate, by using a mixed paste including metal particles and a solder material. The bonding layer may be formed by forming an intermetallic compound, which is formed by heating the mixed paste to react the metal particles with the solder material.