Electronic Package Underfill Using Gas-Driven Capillary Penetration
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Solution Overview
Problem
Existing underfill methods face challenges in improving penetration force to minimize void creation and shorten filling time, particularly in advanced packaging technologies like Chiplet and 2.5D/3D ICs with refined bump integration, leading to defects and contamination issues.
Innovation Solution
A method involving controlled application of a filler using a dispenser and gas discharger to manage filler penetration, including temperature adjustment, ultrasound, and electrohydrodynamic techniques to enhance capillary flow and reduce viscosity, combined with gas pressurization to improve penetration force and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filler is excessively applied to prevent void creation, then void formation is reduced, but the top surface of the device becomes contaminated due to overflow
Solution Approach 1:
The patent replaces the conventional mechanical dispensing system with an electrohydrodynamic (EHD) system that uses electric fields to control filler flow. The EHD dispenser generates electric field-induced fluid motion to precisely deliver filler into the capillary gap, eliminating the need for excessive mechanical application and preventing overflow contamination while ensuring complete void-free filling.
Solution Approach 2:
The patent changes the physical parameters of filler application by controlling electric field strength, voltage, and pulse duration in the EHD system. By adjusting these electrical parameters, the filler flow rate and penetration depth are precisely controlled to match the capillary gap dimensions exactly, preventing both void formation and surface contamination from overflow.
2Productivity
If conventional underfill methods are used, then the process is simple, but filling time is excessive and penetration force is insufficient
Solution Approach 1:
The patent replaces conventional mechanical or capillary-only filling systems with an electrohydrodynamic system that uses electric fields to actively drive filler penetration. This substitution dramatically increases filling speed and penetration force, reducing filling time from minutes to seconds, while the added electrical control components represent manageable complexity for achieving superior filling performance.
3Productivity
If the pitch of the bump is reduced for higher integration density, then device integration is improved, but underfill penetration becomes more difficult
Solution Approach 1:
The patent uses electrohydrodynamic actuation to replace mechanical pressure or passive capillary action, enabling precise control of filler flow at micro-scale dimensions. The electric field can be localized and modulated to match the reduced bump pitch, delivering filler with micron-level precision into narrower capillary gaps, thereby maintaining manufacturing precision even as integration density increases.
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 minimizes void creation and shortens underfill filling time by enhancing filler penetration and reducing viscosity, ensuring consistent quality and miniaturization in semiconductor devices.
Implementation Method 1
a step of discharging a gas towards the filler applied to the side surface of the electronic device using a gas discharger in order to pressurize the filler in a capillary flow direction
Implementation Method 2
a step of transferring heat so that a dispenser for discharging a filler maintains a constant temperature
Implementation Method 3
a filler is charged according to the principle of electrowetting, and then applied between a substrate and a microelectronic device, and then an electric field is applied, so that the wettability of the filler is controlled by the electric force acting on the filler
Data Source
AI summary
The present disclosure relates to a method of electronic devices packaging underfill, the method of electronic devices packaging underfill according to the present disclosure includes a step of loading a substrate, where an electronic device is stacked, on a stage; a step of transferring heat so that the substrate maintains a constant temperature; a step of transferring heat so that a dispenser that discharges a filler maintains a constant temperature; a step of applying a liquid filler for underfilling to a side surface of the electronic device using the dispenser; and a step of discharging a gas towards the filler applied to the side surface of the electronic device using a gas discharger in order to pressurize the filler in a capillary flow direction.