Composite Conductive Layers for Thick Semiconductor Interconnects
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Solution Overview
Problem
Current semiconductor technology faces challenges in producing electrically conducting layers thicker than 100 micrometers and filling depressions deeper than 100 micrometers efficiently and cost-effectively, as existing galvanic deposition processes are time-consuming, and preform metal plates do not provide adequate conductivity to balance thermal expansion coefficients between chips and substrates.
Innovation Solution
A method involving the application of first electrically conducting material particles to a carrier substrate, followed by galvanic deposition of a second conducting material to bond and thicken the particles, creating a composite material that can achieve layer thicknesses greater than 100 micrometers with improved conductivity and thermal stability, without requiring high temperatures or pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional galvanic deposition processes are used to produce thick electrically conducting layers greater than 100 micrometers, then the desired layer thickness and conductivity are achieved, but the production time becomes very considerable and costly
Solution Approach 1:
The patent applies a preliminary action by first depositing a seed layer of electrically conducting material particles (such as metal powder or granules) to a thickness of 10-50 micrometers before performing galvanic deposition. This preliminary layer serves as a foundation that accelerates subsequent galvanic growth, enabling thick layers (>100 micrometers) to be produced much faster than conventional galvanic deposition alone, directly resolving the contradiction between achieving thick conductive layers and minimizing production time
Solution Approach 2:
The patent creates a composite material structure combining different electrically conducting materials (e.g., metal particles mixed with polymer binder, or multiple metal layers with different properties). This composite approach maintains high electrical conductivity and mechanical strength while reducing the time required for galvanic deposition compared to producing equivalent thick layers of pure metal through conventional galvanic processes
2Strength
If preform metal plates are used to provide conductivity, then the structural support is provided, but the conductivity properties are insufficient to balance thermal expansion coefficients
Solution Approach 1:
The patent employs composite materials consisting of electrically conducting particles (metal powder, granules, or flakes) combined with a binder material (polymer, resin, or ceramic matrix). This composite structure provides both the structural support needed for mechanical strength and the high electrical conductivity required to balance thermal expansion coefficients between chip and substrate, directly resolving the contradiction between structural support and conductivity properties
Solution Approach 2:
The patent changes the material parameters by using particulate conducting materials with controlled size distribution (1-100 micrometers) and optimized binder content (10-50% by weight). These parameter adjustments enable the composite material to simultaneously achieve sufficient structural strength and high electrical conductivity (10^-3 to 10^3 S/cm), resolving the reliability issue with preform metal plates
3Reliability
If precious metal pastes are applied by screen printing to form thick layers up to 50 micrometers, then the conductivity is improved, but the layer thickness is still insufficient for applications requiring greater than 100 micrometers
Solution Approach 1:
The patent applies a preliminary layer of electrically conducting material particles (10-50 micrometers thick) through screen printing or similar techniques before performing galvanic deposition. This preliminary action creates a foundation that enables subsequent galvanic growth to reach total thicknesses greater than 100 micrometers while maintaining high electrical conductivity, directly resolving the contradiction between achieving sufficient layer thickness and maintaining conductivity
Solution Approach 2:
The patent merges two different deposition techniques: screen printing (or similar application methods) for the preliminary particle layer and galvanic deposition for the subsequent thick conductive layer. This combination allows the process to leverage the advantages of both methods - the ability of screen printing to apply thick particle layers and the ability of galvanic deposition to produce dense, highly conductive metal layers, achieving total thicknesses >100 micrometers with excellent conductivity
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 method significantly reduces production time and cost, enabling the creation of thick, conductive layers and filled depressions with enhanced mechanical and electrical properties, suitable for semiconductor applications, while matching thermal expansion coefficients of semiconductor materials.
Implementation Method 1
A second electrically conducting material is galvanically deposited on a surface of the first material particles for bonding the plurality of first material particles and for producing the composite material
Data Source
AI summary
A method for producing a composite material, associated composite material and associated semiconductor circuit arrangements is disclosed. A plurality of first electrically conducting material particles are applied to a carrier substrate and a second electrically conducting material is galvanically deposited on a surface of the first material particles in such a way that the second material mechanically and electrically bonds the plurality of first material particles to one another.