臺灣博碩士論文加值系統

In part, the rapid developments in semiconductor technology is due to the advances in the field of contamination control. Purging of wafer carriers, called front opening unified pods (FOUP,) using inert gases is one of the arsenals in fab contamination control. With FOUP purging, the risk of wafer defect formation due to particulates, oxygen, moisture, and airborne molecular contaminants (AMCs) are substantially mitigated, and as such, has contributed significantly to yield improvement. Over the past decade, there have been significant developments in FOUP purge technology. However, being a niche area, its progress has been rather slow but steady. To help encourage the research in FOUP purge technology, this study will mainly focus on conducting a comprehensive review of past and recent works on FOUP purging. A contribution of this study is in helping identify potential areas of improvement in FOUP purge technology. Although not a part of FOUP purge technology, the application of gas curtains is also included in the review. Gas curtains, particularly the modern laminar air curtain, has proved itself to be a great complementary device to FOUP purging. Furthermore, this study takes a closer look on the phenomenon of moisture invasion during FOUP purging at open-door condition. Experiments were performed to investigate a recently observed behavior of moisture invasion during purging at high purge flow rate. The study culminates in discussions of proposed solutions and potential subjects for further investigation.

In part, the rapid developments in semiconductor technology is due to the advances in the field of contamination control. Purging of wafer carriers, called front opening unified pods (FOUP,) using inert gases is one of the arsenals in fab contamination control. With FOUP purging, the risk of wafer defect formation due to particulates, oxygen, moisture, and airborne molecular contaminants (AMCs) are substantially mitigated, and as such, has contributed significantly to yield improvement. Over the past decade, there have been significant developments in FOUP purge technology. However, being a niche area, its progress has been rather slow but steady. To help encourage the research in FOUP purge technology, this study will mainly focus on conducting a comprehensive review of past and recent works on FOUP purging. A contribution of this study is in helping identify potential areas of improvement in FOUP purge technology. Although not a part of FOUP purge technology, the application of gas curtains is also included in the review. Gas curtains, particularly the modern laminar air curtain, has proved itself to be a great complementary device to FOUP purging. Furthermore, this study takes a closer look on the phenomenon of moisture invasion during FOUP purging at open-door condition. Experiments were performed to investigate a recently observed behavior of moisture invasion during purging at high purge flow rate. The study culminates in discussions of proposed solutions and potential subjects for further investigation.

Table of Contents
ABSTRACT i
Acknowledgement iii
List of Tables vi
List of Figures vii
Chapter 1 - Introduction 1
1.1 Background of the Study 1
1.2 Objectives of the Study 3
1.3 Significances of the Study 3
1.4 Scopes and Limitations of the Study 4
Chapter 2 - Strategy for Literature Review 5
2.1 Selection of Relevant Studies 5
2.2 Organization of Chapters 5
Chapter 3 - Review of Literature 6
3.1 Contaminant Removal by Purge Gas 6
3.2 Advances in FOUP Purging 12
3.3 Application of Gas Curtain 17
3.4 Limitations of Purging 23
3.5 Effectiveness of High Purge Rate 27
Chapter 4 - Flow Visualization of Moisture Invasion 35
4.1 Methodology 35
4.2 Experiment Set-up 35
4.2.1 Cleanroom 35
4.2.2 Equipment Front End Module 36
4.2.3 Front Opening Unified Pod 39
4.2.4 Clean Dry Air Generation System 39
4.2.5 Flow Visualization Set-up 41
4.3 Equipment 42
4.3.1 Digital Camera 42
4.3.2 Camera Lens 43
4.3.3 Laser Light Sheet Generator 43
4.3.4 Smoke Generator 44
4.3.5 Smoke Distributor 45
4.3.6 Design of Experiment 46
4.4 Results 46
4.4.1 Effect of Increasing Purge Flow Rate 46
4.4.2 Comparison with Previous Data 49
4.5 Discussion 52
Chapter 5 - Recommendations 55
5.1 Optimization of Purge and Air Curtain Flow Rates 55
5.2 Use of Single Panel-type Diffuser 57
5.3 Application of Nitrogen EFEM 57
5.4 Modification of Load Port Interface 58
Chapter 6 - Conclusion 60
References 61

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