Liquid Ejection Pulse Control for Uniform Underfill Fillets
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Solution Overview
Problem
Existing methods for underfilling in semiconductor packaging face challenges in maintaining uniform ejection of liquid resin due to viscosity changes and varying bump densities, leading to non-uniform fillet formation and inefficiencies in processing time and throughput.
Innovation Solution
The method adjusts the ratio of ejection pulses to pause pulses in each application region, maintaining a constant relative speed and ejection rate, allowing for precise control of the ejection amount and pattern flexibility, even with different bump arrangements and corner configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the ejection amount is increased to compensate for viscosity increase over time, then the application amount becomes excessive in regions with high bump density, but if the ejection amount is decreased to match high bump density regions, then the application amount becomes insufficient in regions with low bump density
Solution Approach 1:
The patent applies local quality by dividing the application region into multiple regions with different ejection amounts based on bump density. The control unit sets a first ejection amount for a first region with high bump density and a second ejection amount (larger than the first) for a second region with low bump density, ensuring uniform fillet formation across regions with varying bump densities
Solution Approach 2:
The patent implements dynamics by making the ejection amount adjustable and variable according to the specific application region. The ejection device can dynamically change the ejection amount based on real-time control signals from the control unit, allowing adaptation to different bump density conditions without physical reconfiguration
2Quantity of substance
If the moving speed of the ejection device is reduced to increase ejection amount, then the application amount increases, but the processing time increases and throughput decreases
Solution Approach 1:
The patent changes the parameter of ejection amount independently from moving speed. Instead of reducing moving speed to increase ejection amount, the system directly controls the ejection amount parameter through the ejection device's control unit, allowing ejection amount adjustment without affecting processing speed or throughput
3Reliability
If the ejection amount is increased to ensure sufficient filling in low bump density regions, then the fillet shape becomes non-uniform with excessive material in high bump density regions
Solution Approach 1:
The patent ensures sufficient filling and uniform fillet shape by applying local quality - different ejection amounts are set for different regions. The control unit determines the bump density for each region and sets appropriate ejection amounts, ensuring that each region receives the precise amount of liquid material needed for uniform fillet formation without excessive or insufficient material
4Ease of manufacture
If a fixed ejection pattern is used for all regions, then the application process is simple, but the application amount cannot be adjusted for different bump densities
Solution Approach 1:
The patent implements dynamics by making the ejection pattern adjustable and adaptive. The control unit can dynamically determine application regions based on bump density and set different ejection amounts for different regions, allowing precise application amount control while maintaining operational simplicity through automated control
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 stabilizes the fillet shape and maintains constant throughput by adjusting pulse ratios without altering the relative speed or pattern length, ensuring accurate and uniform application of the liquid material.
Implementation Method 1
filling, based on a capillary action, a liquid material ejected from an ejection device into a gap between a substrate and a workpiece placed on the substrate
Data Source
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AI summary
[Object] An application method, an application device, and a program are provided in which change of an ejection amount is corrected with high accuracy, and a shape of an applied liquid material or a fillet shape can be stabilized. [Solution] A liquid material application method for filling, based on a capillary action, a liquid material ejected from an ejection device, the application method comprising a step of preparing an application pattern made up of a plurality of continuous application regions, a step of preparing a plurality of cycles and allocating the cycles to the application regions, the cycles each including one ejection pulse combined with a plurality of pause pulses at a predetermined ratio, a step of performing application to the application regions with the cycles allocated respectively to the application regions, a correction amount calculation step of measuring an ejection amount at timing of a correction period that is set in advance, and calculating a correction amount of the ejection amount, and a step of adjusting a ratio of the pause pulses to one ejection pulse for one or more cycles based on the correction amount calculated in the correction amount calculation step, wherein a length of the pause pulse is set to be sufficiently shorter than a length of the ejection pulse. An application device and a program are provided which carry out the application method.