Optical Thermal Treatment in IC Packages to Limit Warpage
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Solution Overview
Problem
High-temperature thermally based processes in semiconductor package manufacturing cause stress due to differential expansion of components, leading to issues like warpage and unintended solder reflow.
Innovation Solution
Localized optical thermal treatment using a light absorption material that rapidly increases in temperature when exposed to pulsed light, allowing for selective heating of specific areas within the semiconductor package while keeping other components at lower temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If high-temperature thermal processes are used for copper annealing, material cure, and solder reflow, then these manufacturing processes can be completed, but package stress and warpage occur due to differential expansion of components
Solution Approach 1:
The patent applies local quality by using light absorption material selectively positioned at specific locations within the semiconductor package that require thermal treatment. When exposed to pulsed light, only these localized areas generate heat for processes like solder reflow or material cure, while other components remain at lower temperatures. This selective localized heating eliminates differential thermal expansion across the entire package, preventing warpage and stress while completing necessary manufacturing processes.
2Temperature
If entire package heating is applied for thermal processing, then uniform temperature distribution is achieved, but different components expand at different rates causing internal stresses
Solution Approach 1:
The patent segments the thermal treatment process by dividing the package into zones: heated zones containing light absorption material that converts optical energy to thermal energy, and unheated zones where sensitive components remain at ambient or lower temperatures. This segmentation is achieved by strategically placing light absorption material only where thermal processing is needed, allowing uniform temperature distribution within targeted areas without inducing internal stresses from differential expansion across the entire package.
3Ease of manufacture
If conventional thermal processing is used, then manufacturing processes can be completed, but sensitive components may be damaged due to high temperatures
Solution Approach 1:
The patent introduces light absorption material as an intermediary substance that mediates the thermal processing function. This material absorbs pulsed optical energy and converts it to localized heat, acting as a buffer between the energy source and sensitive components. The intermediary light absorption material enables complete manufacturing processes (solder reflow, material cure, copper annealing) while protecting sensitive components from direct exposure to high temperatures, as heat is generated only at specific locations away from temperature-sensitive areas.
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 enables reliable thermal processing at lower temperatures, reducing stress and damage to sensitive components, thereby increasing the reliability and operational life of semiconductor packages.
Implementation Method 1
light absorption material which can be a dielectric material and to rapidly increase in temperature in response to being provided with a pulsed light
Implementation Method 2
The localized heating occurs by applying a pulsed light to a light absorption material, which can be a dielectric material. In turn, the light absorption material rapidly increases in temperature
Data Source
AI summary
Methods and apparatus for optical thermal treatment in semiconductor packages are disclosed. A disclosed example integrated circuit (IC) package includes a dielectric substrate, an interconnect associated with the dielectric substrate, and light absorption material proximate or surrounding the interconnect, the light absorption material to increase in temperature in response to being exposed to a pulsed light for thermal treatment corresponding to the IC package.