Hybrid Bonding Structure for Low-Temperature Semiconductor Packaging
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Solution Overview
Problem
Highly integrated and thin semiconductor packages face damage due to temperature-related stresses during soldering processes, as existing SAC-based solders have a high melting point, leading to tensile and compressive stresses that can cause substrate bending and stretching.
Innovation Solution
A hybrid bonding structure using a solder ball and solder paste with ceramic particles, such as CeO2, that have a specific composition and surface treatment, allowing for low-temperature bonding with improved mechanical properties like modulus of elasticity and thermal expansion, reducing brittleness and defect rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If SAC-based solder is used for bonding, then bonding strength is achieved, but substrate bending and stretching occur due to high melting point and temperature-related stresses
Solution Approach 1:
The patent changes the material parameters by replacing SAC-based solder with low-melting-point glass particles. The glass particles have a melting point of 400°C or lower, significantly reducing the bonding temperature compared to traditional SAC solder. This parameter change resolves the contradiction by achieving bonding strength through glass transition and softening rather than high-temperature melting, thereby preventing substrate bending and stretching.
Solution Approach 2:
The patent uses composite materials by combining glass particles with specific compositional ratios (SiO2: 30-70 wt%, B2O3: 10-40 wt%, Al2O3: 5-20 wt%, and other oxides). This composite approach allows the bonding material to achieve both low melting point and adequate bonding strength, resolving the contradiction between reduced temperature and maintained bonding integrity.
2Strength
If high melting point solder is used, then bonding strength is achieved, but thermal deformation and damage occur in highly integrated and thin semiconductor packages
Solution Approach 1:
The patent changes the thermal parameters by using glass particles with melting point of 400°C or lower, reducing the bonding temperature from the typical 200-230°C range of SAC solder to a lower temperature process. This parameter change directly addresses the thermal deformation issue in thin semiconductor packages while maintaining bonding strength through glass transition and softening mechanisms.
Solution Approach 2:
The patent employs glass particles that undergo irreversible softening and bonding at low temperatures, effectively serving as a single-use bonding material that prevents thermal damage. The glass particles are designed to soften and bond elements together without requiring high-temperature processing that would cause thermal deformation in sensitive semiconductor packages.
3Temperature
If low-temperature bonding is implemented, then thermal deformation is reduced, but bonding strength and reliability may be compromised
Solution Approach 1:
The patent uses composite glass particle materials with optimized compositional ratios to achieve both low melting point and adequate bonding strength. The specific composition (SiO2: 30-70 wt%, B2O3: 10-40 wt%, Al2O3: 5-20 wt%, and other oxides) enables the glass particles to soften and bond elements effectively at low temperatures while maintaining sufficient bonding strength and reliability.
Solution Approach 2:
The patent changes the physical parameters of the bonding material by using glass particles with controlled particle size (5-50 μm) and specific melting points (400°C or lower). These parameter changes enable the material to achieve adequate bonding strength at low temperatures through glass transition and softening, rather than requiring high-temperature melting as in traditional soldering.
4Ease of manufacture
If traditional soldering materials are used, then bonding is achieved, but brittleness and defect rates increase in thin semiconductor packages
Solution Approach 1:
The patent changes the material parameters by replacing traditional soldering materials with glass particles having specific compositional ratios and particle sizes. This parameter change reduces brittleness and defect rates in thin semiconductor packages while maintaining ease of manufacture through a simplified low-temperature bonding process that eliminates the need for complex high-temperature soldering operations.
Solution Approach 2:
The patent uses composite glass particle materials with optimized compositions to reduce brittleness and defect rates. The specific combination of oxides (SiO2, B2O3, Al2O3, and others) creates a bonding material that is less brittle and more reliable in thin semiconductor packages, while the low-temperature processing further reduces defect formation.
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 hybrid bonding structure effectively bonds semiconductor devices at low temperatures, reducing thermal deformation and improving mechanical strength, thus minimizing defects and enhancing the reliability of semiconductor packages.
Implementation Method 1
The solder paste may include solder particles, the solder particles including at least one of In, Zn, SnBiAg alloy, or SnBi alloy, a flux, and ceramic particles
Implementation Method 2
A hybrid bonding structure may include a solder ball and a solder paste bonded to the solder ball
Implementation Method 3
The hybrid bonding structure may have a coefficient of thermal expansion in a range of about 14 μm/(m·K) to about 40 μm/(m·K)
Data Source
AI summary
A hybrid bonding structure and a semiconductor including the hybrid bonding structure are provided. The hybrid bonding structure includes a solder ball and a solder paste bonded to the solder ball. The solder paste may include solder particles including at least one of In, Zn, SnBiAg alloy, or SnBi alloy, and ceramic particles. The solder paste may include a flux. The solder particles may include Sn(42.0 wt %)-Ag(0.4 wt %)-Bi(57.5−X) wt %, and the ceramic particles include CeO2(X) wt %, where 0.05≤X≤0.1.