Silver Paste Composition for Low-Pressure Large-Area Die Bonding
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Solution Overview
Problem
Wide bandgap semiconductor devices require interconnection materials suitable for large-area bonding to meet high heat dissipation needs, but existing silver sintering technologies require increased sintering temperatures and pressures, which complicate processes, damage chips, and increase costs.
Innovation Solution
A silver paste prepared using a silver-ammonia complex and an aldehyde-containing organic solvent, with specific molar ratios, allows for large-area packaging and interconnection of wide-bandgap semiconductor devices under low sintering pressure (0-1 MPa) and low temperature (200-300°C).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sintering temperature and pressure are increased to achieve large-area bonding, then bonding strength is improved, but process complexity increases and chip damage risk increases
Solution Approach 1:
The patent changes the chemical composition parameters of the silver paste by incorporating organic additives (carboxylic acid and its derivatives) that modify the sintering behavior. This allows achieving adequate bonding strength at lower temperatures and pressures, thereby reducing process complexity and equipment requirements while maintaining connection reliability.
Solution Approach 2:
The organic additives (carboxylic acid and derivatives) act as intermediary substances that facilitate the sintering process. These additives lower the sintering temperature by forming intermediate compounds or modifying the melting behavior of silver particles, enabling large-area bonding without requiring high temperatures and pressures, thus simplifying the overall process.
2Strength
If sintering temperature and pressure are increased to achieve large-area bonding, then bonding strength is improved, but chip damage increases
Solution Approach 1:
The patent modifies the chemical composition of the silver paste by adding carboxylic acid and its derivatives, which change the sintering characteristics. This enables achieving sufficient bonding strength at reduced temperatures and pressures, thereby minimizing thermal and mechanical stress on chips and preventing chip damage during the sintering process.
Solution Approach 2:
The carboxylic acid additives serve as intermediary substances that mediate the bonding process. They facilitate particle bonding at lower temperatures through chemical interactions, reducing the need for high-energy sintering conditions that could damage sensitive wide bandgap semiconductor chips.
3Strength
If sintering temperature and pressure are increased to achieve large-area bonding, then bonding strength is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the chemical formulation of the silver paste by incorporating carboxylic acid and its derivatives as cost-effective additives. This modification enables the sintering process to proceed at lower temperatures and pressures, reducing energy consumption and equipment requirements, thereby lowering manufacturing costs while maintaining adequate bonding strength for large-area applications.
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 silver paste achieves well-bonded, uniform, and compacted connection interfaces with shear strength up to 35 MPa, enabling reliable large-area packaging and interconnection of electronic devices without damaging chips or increasing costs.
Implementation Method 1
the aldehyde-containing organic solvent and the silver-ammonia complex undergo a silver mirror reaction, which is conducive to promoting decomposition of the silver paste
Implementation Method 2
the aldehyde-containing organic solvent has a strong reducing property and realizes decomposition through self-oxidation
Implementation Method 3
large-area (≥30×30 cm2) packaging and interconnection of a wide-bandgap semiconductor device can be well achieved under a low sintering pressure (0-1 MPa) at a low sintering temperature (200-300° C.)
Data Source
AI summary
The present disclosure relates to silver paste, and a preparation method and a use thereof, which belong to the field of device packaging technology. The silver paste of the present disclosure is prepared by a silver-ammonia complex and an aldehyde-containing organic solvent, wherein a molar ratio of the silver-ammonia complex to the aldehyde-containing organic solvent is in a range of from 1:1 to 1:5; the silver-ammonia complex is prepared by a silver β-ketocarboxylate and an amino-containing organic solvent; and a molar ratio of the silver β-ketocarboxylate to the amino-containing organic solvent is in a range of from 1:1 to 1:5. The silver paste of the present disclosure can achieve large-area (≥30×30 cm2) packaging and interconnection of a wide-bandgap semiconductor device within 300° C. under a low pressure (≤1 MPa) or without pressures.