Underfill Dispensing Pulse Control for Stable Fillet Width

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Solution Overview

Problem

In the underfilling process for semiconductor packaging, existing methods face challenges in maintaining a consistent ejection amount and shape of liquid material due to changes in viscosity, leading to inadequate filling and irregular fillet formation, especially when applying the material along complex shapes or corners, which requires adjusting the dispenser speed and can result in mechanical burdens and vibrations.

Innovation Solution

A method that adjusts the number of ejection and pause pulses in ejection cycles to correct the ejection amount without changing the frequency, allowing for stable application patterns across varying shapes and penetration speeds, using a control unit to manage the ejection device's operation and ensure consistent application without altering the moving speed or length of the application pattern.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the dispenser speed is adjusted to maintain consistent ejection amount along complex shapes or corners, then the application precision is improved, but the mechanical burden and vibrations increase

Engineering Contradiction:
Improveapplication precisionVSAvoidmechanical burden
Core Design Contradiction:
Manufacturing precisionVSForce

Solution Approach 1:

The application pattern is divided into multiple segments (first application region, second application region, third application region) with different ejection cycle configurations. Each segment can be independently optimized for its specific geometric requirements, allowing precise material application along complex shapes and corners without requiring speed adjustments that would increase mechanical burden.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between different ejection cycle types (first, second, third ejection cycles) based on the current application region. This dynamic adaptation allows the ejection parameters to be optimized for each specific region's requirements, maintaining application precision while avoiding the need to change overall dispenser speed.

Inventive Principle:
Principle #15Dynamics

2Quantity of substance

If the number of ejection pulses is increased to compensate for viscosity change, then the ejection amount is improved, but the application pattern consistency deteriorates

Engineering Contradiction:
Improveejection amountVSAvoidapplication pattern consistency
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

Different ejection cycles with different numbers of ejection pulses are assigned to different application regions based on local requirements. The first ejection cycle uses a first number of ejection pulses for the first application region, the second ejection cycle uses a second number for the second region, and the third ejection cycle uses a third number for the third region. This local optimization ensures each region receives the appropriate material quantity while maintaining overall pattern consistency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system changes the number of ejection pulses parameter in different ejection cycles to compensate for viscosity changes and ensure consistent material application. By adjusting this parameter locally in different regions rather than globally, the system maintains application pattern consistency while achieving the required ejection amount.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If the ejection frequency is changed to control ejection amount, then the material application quantity is improved, but the application speed stability deteriorates

Engineering Contradiction:
Improveejection amountVSAvoidapplication speed stability
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The system uses periodic ejection cycles with different numbers of ejection pulses (first, second, third ejection cycles) to control material application quantity. Each ejection cycle is a periodic sequence that can be repeated, allowing precise control of ejection amount through the number of pulses in each cycle while maintaining stable application speed through consistent cycle timing.

Inventive Principle:
Principle #19Periodic action

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 enables precise control over the ejection amount, maintaining a constant fillet width and reducing mechanical burdens, allowing for accurate and efficient application of liquid material across different shapes and speeds, improving the stability and accuracy of the underfilling process.

Implementation Method 1

filling the resin into a gap between the semiconductor chip and the substrate by utilizing a capillary action

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2444164B1Method for applying liquid material, and apparatus and program for same
Publication Date: 2016.07.13 MUSASHI ENG INC
  • EP2444164B1 patent drawingFigure 1
  • EP2444164B1 patent drawingFigure 2
  • EP2444164B1 patent drawingFigure 3(a)~3(c)

AI summary

Provided are a method for filling a liquid material, and an apparatus and a program for the same, which make it possible, without changing a moving speed of an ejection device, to correct a change in ejection amount and to stabilize an application shape. Disclosed are: a method for filling a liquid material into a gap between a substrate and a work by using the capillary action; and an apparatus and a program for the same. The method comprises the steps of: generating an application pattern consisting of a plurality of application areas continuous to one another; assigning a plurality of ejection cycles, each obtained by combining the number of ejection pulses and the number of pause pulses at a predetermined ratio therebetween, to each of the application areas; and measuring an ejection amount at correction intervals and calculating a correction amount for the ejection amount. The method further comprises at least any one of the steps of: adjusting the numbers of ejection pulses and the numbers of pause pulses, which are included in the application pattern, based on the calculated correction amount; and adjusting the length of any application area continuous to at least one application area without changing ejection amounts per unit time in the respective application areas.