Design and Control of Piezostack Based Jetting Dispenser for Semiconductor Electronic Packaging :Doctor of philosophy - Major: Machanical

工學博士學位論文

Design and Control of Piezostack Based Jetting

Dispenser for Semiconductor Electronic Packaging

2009年 2月

仁荷大學校 大學院

機械工學科

Nguyen Quoc Hung

工學博士學位論文

Design and Control of Piezostack Based Jetting

Dispenser for Semiconductor Electronic Packaging

2009年 2月

指導敎授 崔 承 福

이 論文을 博士學位 論文으로 提出함

仁荷大學校 大學院

機械工學科(固體 및 生産工學專攻)

Nguyen Quoc Hung

Design and Control of Piezostack Based Jetting

Dispenser for Semiconductor Electronic Packaging

by

Nguyen Quoc Hung

A THESIS

Submitted to the faculty of

INHA UNIVERSITY

in partial fulfillment of the requirements

for the degree of

DOCTOR OF PHILOSOPHY

Mechanical Engineering

February 2009

This thesis submitted for the application of

The degree of

DOCTOR OF PHILOSOPHY

February 2009

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-i￾ABSTRACT

Fluid dispensing is a method by which fluid materials such as epoxy, adhesive,

encapsulant and hydrogel are delivered in a precisely controlled manner. In recent

years, jetting dispensers have been widely used in many applications, especially in the

semiconductor packaging technology such as dam-fill and underfill processes in

integrated circuit (IC) encapsulation to protect an IC chip from external environment

and prevent its break away. Generally, present jetting dispensers are driven by

conventional actuating mechanism such as pneumatics, hydraulics, servo motors etc.

The primary limitation of these actuating mechanisms is slow time response, which

limits operating frequency of the dispensing system. Therefore, conventional jetting

dispensers can not provide very small dispensing dot size while dispensing flow rate is

still kept at high value. However, modern semiconductor packaging processes become

increasingly dense and chip size is smaller and smaller, which require a more

advanced jetting dispenser to dispense nanoliter-volume of adhesives at high flow rate.

The main contribution of this work is to develop a new jetting dispenser that can

provide high flow rate and small dot sizes in order to meet the requirements in modern

semiconductor packaging technology. In order to achieve this goal, a high frequency

actuator should be employed and piezoelectric actuator is a potential candidate. As is

well known, the piezoelectric actuator is one of smart materials which can offer large

force, fast response and high operating frequency. However, the primary limitation of

the piezoelectric material is its small strain. For dispensing of high viscosity fluid such

as adhesive in semiconductor packaging process, the output displacement of the

piezoelectric actuator must be magnified to a certain value (  0.5mm). Several

magnification mechanisms such as hydraulic magnification, flexible beam and

resonant mechanism are considered in this study. Consequently, this research work

focus on design, modeling and control of jetting dispenser driven by piezoelectric

actuator via a magnification mechanism. In order to accurate model dynamic

behaviors of dispensing fluid, a new approach for modeling unsteady adhesive fluid

flow is proposed and employed