3DIC Package Warpage Control via Underfill Curing Pressure
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Solution Overview
Problem
The packaging of integrated circuits faces issues with warpage due to thermal expansion differences between silicon dies and package substrates, leading to irregular joints and reduced yield, as organic materials used in substrates warp during reflow processes.
Innovation Solution
A method involving a jig system with through-openings for vacuuming or air blowing during underfill curing to apply corrective forces, flattening the substrates and reducing warpage, using a combination of vacuuming for positive warpage and air blowing for negative warpage, with optional blockers to control the force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic materials are used as dielectric materials in package substrates, then ease of lamination is improved, but warpage occurs during reflow due to elevated temperatures
Solution Approach 1:
The patent applies parameter changes by modifying the physical state and pressure conditions during the underfill curing process. Specifically, it uses vacuuming to remove air pockets and apply negative pressure, or air blowing to apply positive pressure, thereby changing the pressure parameter to counteract thermal warpage and achieve substrate flattening without altering the organic dielectric material composition
Solution Approach 2:
The patent implements preliminary action by performing vacuuming or air blowing during the underfill curing process before the substrate cools down. This timing is critical because it addresses the warpage while the substrate is still warm and pliable, allowing the applied pressure to effectively flatten the substrate before thermal contraction occurs
2Shape
If vacuuming or air blowing is applied during underfill curing to flatten substrates, then warpage is reduced, but device complexity increases
Solution Approach 1:
The patent uses an intermediary approach by introducing a curing environment (vacuum chamber or controlled atmosphere) that mediates between the thermal warpage force and the substrate. The vacuum or air flow acts as an intermediary force that transmits pressure uniformly across the substrate surface during curing, simplifying the control mechanism compared to direct mechanical pressing
Solution Approach 2:
The patent applies pneumatic principles by using vacuuming (negative pressure) or air blowing (positive pressure) to flatten substrates during underfill curing. This replaces complex mechanical pressing systems with simpler pneumatic control, where pressure can be easily adjusted and applied uniformly across large substrate areas through flexible membranes or direct gas flow
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
The method effectively reduces warpage in both package substrates and components, resulting in improved packaging yield by ensuring substrates remain flat post-curing, thereby enhancing the bonding process.
Implementation Method 1
vacuuming for positive warpage
Implementation Method 2
a force is applied to flatten the first package component. The force is applied by performing an action selected from the group consisting essentially of vacuuming and air blowing
Implementation Method 3
air blowing for negative warpage
Implementation Method 4
a force is applied to flatten the first package component. The force is applied by performing an action selected from the group consisting essentially of vacuuming and air blowing
Implementation Method 5
The underfill is cured
Data Source
AI summary
A method includes dispensing an underfill between a first package component and a second package component, wherein the first package component is placed on a lower jig, and the second package component is over and bonded to the first package component. A through-opening is in the lower jig and under the first package component. The underfill is cured, wherein during the step of curing the underfill, a force is applied to flatten the first package component. The force is applied by performing an action selected from the group consisting of vacuuming and air blowing through the through-opening.