3D IC Soldering With On-Chip Heat Sources
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Solution Overview
Problem
The manufacturing process of 3D integrated circuits faces challenges in ensuring adequate electrical connections and bonding between components, leading to complex processes and high scrap rates due to faulty components and connections, which are not detected until after soldering.
Innovation Solution
A method that involves pre-soldering testing and burn-in testing using temporary connections, with on-chip heat sources to manage temperature and minimize warping, allowing only functional components to be soldered and maintaining alignment through pressure differentials and thermal monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional soldering processes are used for 3D integrated circuits, then manufacturing complexity is reduced, but scrap rate increases due to undetected faulty components and connections
Solution Approach 1:
The patent performs burn-in testing and electrical connectivity tests before soldering using temporary connections. This preliminary action identifies faulty components and connections early, allowing them to be replaced before permanent soldering, thereby increasing yield without requiring fundamentally complex manufacturing processes.
Solution Approach 2:
The patent uses temporary connections as intermediaries during testing and burn-in procedures. These temporary connections allow electrical testing to be performed before permanent soldering, enabling detection of faulty components without requiring complex integrated testing equipment in the final assembly.
2Manufacturing precision
If uniform heating is applied during soldering, then process simplicity is maintained, but warping increases affecting alignment
Solution Approach 1:
The patent implements location-dependent heating profiles where different regions of the 3D integrated circuit receive different amounts of heat. This local quality approach prevents warping by compensating for thermal expansion differences in various regions, maintaining alignment precision without requiring overly complex heating equipment.
Solution Approach 2:
The patent changes heating parameters (temperature, duration, distribution) based on location within the 3D integrated circuit. By adjusting these parameters locally, the process achieves precise alignment while managing warping, balancing manufacturing precision with process complexity.
3Reliability
If all components are soldered without prior testing, then productivity is maximized, but scrap rate increases due to faulty components
Solution Approach 1:
The patent performs burn-in testing and electrical connectivity tests before soldering using temporary connections. This preliminary action identifies faulty components early in the process, allowing replacement before permanent soldering. While this adds steps, it prevents rework of soldered assemblies and improves overall functional connection reliability.
Solution Approach 2:
The patent allows the process to skip ahead to soldering only for components that pass preliminary testing. Functional components proceed directly to soldering, while faulty ones are identified and replaced. This selective approach maintains productivity by avoiding unnecessary testing of already-functional components while ensuring reliability.
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 approach increases yield by ensuring only functional components are soldered, reduces warping, and maintains alignment during testing and soldering, thereby improving the reliability and efficiency of the 3D integrated circuit manufacturing process.
Implementation Method 1
activating a first on-chip heat source to reflow a first portion of the plurality of solder bumps
Implementation Method 2
the first local-hot-zone has a temperature that is equal to or higher than the melting temperature of the solder
Implementation Method 3
minimize warping
Data Source
AI summary
A method for soldering three-dimensional integrated circuits is provided. A three-dimensional integrated circuit is heated to a base temperature, wherein the base temperature is lower than the melting point of a solder, and wherein the three-dimensional integrated circuit includes a plurality of solder bumps. A first on-chip heat source reflows a first portion of the plurality of solder bumps that is within a first local-hot-zone. A second on-chip heat source reflows a second portion of the plurality of solder bumps that is within a second local-hot-zone.