Hybrid Interconnects for High-Temperature Semiconductor Assembly
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Solution Overview
Problem
Current 3D assembly techniques for semiconductors face challenges such as high costs, temperature requirements, and reliability issues due to the need for specific metal layers and the difficulty in compensating for height differences between components, particularly in flip chip and stud bump technologies.
Innovation Solution
The development of hybrid electrical and mechanical interconnects using intermediate metal interconnect elements combined with sintered joints from metal microparticles or nanoparticles, allowing for temperature resistance and height compensation through varying numbers and sizes of interconnect elements and joints, which can be fabricated at low pressures and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder bump technique is used for flip chip assembly, then electrical and mechanical contact is ensured, but the melting point requirement limits temperature resistance and additional metal layers increase cost and complexity
Solution Approach 1:
The patent changes the material parameter by replacing traditional solder bumps with intermediate interconnect elements made of high-melting-point metals (tungsten, molybdenum, tantalum, niobium, or rhenium). These materials have melting points above 300°C, enabling the assembly to withstand high temperatures without the limitations of solder melting points.
Solution Approach 2:
The invention creates a composite interconnect structure combining intermediate interconnect elements (high-melting-point metal) with sintered metal joints (silver, gold, or copper paste). This composite approach provides both mechanical strength from the intermediate element and electrical conductivity from the sintered joint, while eliminating solder melting point constraints.
2Adaptability or versatility
If stud bump technology is used, then integration is improved, but the need for specific metal layers and high pressure increases manufacturing complexity and cost
Solution Approach 1:
The intermediate interconnect elements serve multiple functions: they provide mechanical support, electrical conductivity, and height compensation. The sintered metal joints similarly provide both electrical connection and mechanical bonding, eliminating the need for separate specialized layers required by traditional stud bump technology.
Solution Approach 2:
The patent extracts and eliminates the requirement for specific metal layers (such as nickel and copper underlayers) by using intermediate interconnect elements that can be directly formed on various pad metallizations. This simplifies the manufacturing process by removing complex metallization sequence requirements.
3Reliability
If traditional interconnect methods are used, then electrical connection is achieved, but height differences of several μm or tens of μm cannot be compensated
Solution Approach 1:
The intermediate interconnect elements can be formed with varying heights to dynamically adapt to different pad height differences. The sintered metal joints also provide flexible height adjustment capability, allowing the assembly to compensate for height variations of several micrometers to tens of micrometers between components.
4Reliability
If soldering method is applied, then electrical contact is made, but risk of short circuit increases when distances between electrodes are small
Solution Approach 1:
The sintered metal joints use a paste formulation that sinteres to form solid, stable connections. This process creates well-defined interconnect structures that prevent solder bridging and short circuits, even when electrode distances are small, eliminating the harmful effect of short circuit risk associated with traditional soldering.
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 solution enables reliable, high-conductivity interconnects that operate above 300°C with low pressure and temperature, compensates for height differences, and reduces the risk of short circuits, while being compatible with various metal finishings and encapsulating materials.
Implementation Method 1
at least one sintered joint of metal microparticles or nanoparticles stacked with said first intermediate metal interconnect element
Data Source
AI summary
An assembly includes at least one first element comprising at least one first electrical bonding pad; at least one second element comprising at least one second electrical bonding pad; electrical and mechanical interconnect means, wherein the electrical and mechanical interconnect means comprise at least: at least one first intermediate metal interconnect element, on the surface of at least the first electrical bonding pad; at least one sintered joint of metal microparticles or nanoparticles stacked with the first intermediate metal interconnect element; the melting point of the first intermediate metal interconnect element being greater than the sintering temperature of the metal microparticles or nanoparticles. A method for fabricating an assembly is also provided.