Additive Solder and Copper Interconnect Formation
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Solution Overview
Problem
Current techniques for forming solder bumps on integrated circuits are expensive and complex, especially for varied geometries, and forming copper traces often involve wasteful subtractive processes, leading to high costs, particularly in low-volume production.
Innovation Solution
The use of aerosol jet printing, inkjet printing, binder printing, and powder laser sintering techniques to deposit and form solder and copper interconnect structures, which are simpler, more flexible, and reduce material waste, allowing for the creation of taller bumps and varied sizes with fewer tools and lower residue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional plating, paste printing, and ball placement techniques are used to form solder bumps, then solder bumps can be formed on IC substrates, but the process becomes expensive and complex especially for varied geometries
Solution Approach 1:
The patent inverts the traditional approach by using additive manufacturing (aerosol jet printing) instead of subtractive or assembly-based methods. Rather than placing pre-formed balls or applying paste that requires complex reflow, the system directly deposits and forms solder bumps in a single additive process, simplifying the overall manufacturing complexity while maintaining reliability
Solution Approach 2:
The aerosol jet printing system serves multiple functions: it deposits solder material, forms varied geometries, and creates different bump sizes all through a single unified process. This multi-functional approach eliminates the need for separate tools and processes for different bump configurations, reducing overall process complexity
2Manufacturing precision
If subtractive processes are used to form copper traces, then conductive traces can be created, but material is wasted resulting in high costs particularly for low volume production
Solution Approach 1:
The patent applies additive manufacturing (aerosol jet printing) to form copper traces instead of using traditional subtractive etching processes. This inversion allows material to be deposited only where needed, eliminating the widespread material removal and waste associated with subtractive methods, thereby reducing copper material waste while maintaining trace formation precision
Solution Approach 2:
The system changes the manufacturing parameter from subtractive to additive processing. By using controlled material deposition with adjustable parameters (deposit amount, pattern, geometry), the process achieves precise copper trace formation without the inherent material waste of etching and subtraction methods
3Ease of manufacture
If screen printing is used to form conductive traces, then the process is simplified, but yield and conductivity issues arise compared to sputter seed and plated traces
Solution Approach 1:
The patent replaces screen printing (a mechanical stencil-based process) with aerosol jet printing (a controlled deposition process). This substitution eliminates the resolution limits and material waste of screen printing while achieving better conductivity control and yield through precise material placement and composition control
Solution Approach 2:
The system changes the deposition mechanism from screen printing to aerosol jet printing, allowing control over material composition, particle size, and deposition parameters. This enables optimization of both simplicity and reliability by adjusting parameters such as ink formulation, deposition rate, and curing conditions to achieve high conductivity
4Adaptability or versatility
If traditional solder bumping techniques are used, then solder bumps can be formed, but different geometries require different tools and processes increasing complexity
Solution Approach 1:
The aerosol jet printing system is designed as a universal tool that can form various bump geometries and sizes through software control and parameter adjustment. A single system handles all bump types by modifying deposition parameters, eliminating the need for multiple specialized tools and processes for different geometries
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
These methods reduce production costs, improve flexibility in producing different bump sizes, and enhance the quality of solder and copper interconnects, achieving higher throughput and potentially lower costs while minimizing residue and material usage.
Implementation Method 1
depositing a solderable material on the IC substrate using an aerosol jet printing system
Implementation Method 2
aerosol jet printing system including a chamber configured to form an aerosol including the solderable material and a print head configured to propel the aerosol to the substrate surface
Implementation Method 3
The print head may be positioned about three millimeters to five millimeters from a surface of the work piece upon which the solderable material is deposited. In some embodiments, the print head may be configured to heat the deposited solderable material to a reflow temperature to form one or more solder bumps on the work piece
Implementation Method 4
depositing a solderable material on the IC substrate using a powder laser sintering system
Implementation Method 5
powder laser sintering system
Data Source
AI summary
Embodiments of the present disclosure are directed toward formation of solder and copper interconnect structures and associated techniques and configurations. In one embodiment, a method includes providing an integrated circuit (IC) substrate and depositing a solderable material on the IC substrate using an ink deposition process, a binder printing system, or a powder laser sintering system. In another embodiment, a method includes providing an integrated circuit (IC) substrate and depositing a copper powder on the IC substrate using an additive process to form a copper interconnect structure. Other embodiments may be described and/or claimed.