臺灣博碩士論文加值系統

隨著整合型超大積體電路的密度增加，多層金屬導線間介電層的製作技術已經越來越重要。而在先進的邏輯元件裡，金屬層中的介電層已經增加到四到五層。二氧化矽通常被用來當作兩金屬導線間的材料。又因為氟氧化矽具有低介電常數的優點，因此被採用作為兩金屬導線間的材料。此種材料雖然具有低介電常數的優點，但水氣的吸收是主要的缺點。因此，我們採用退火來去除在氟氧化矽層的水氣。我們因此可以氧化層的電性和得到一個穩定且介電常數低的氧化膜。
在本篇論文的目的主要是探討利用液相沉積法成長的氟氧化矽，經過退火後的化學性和電性。退火溫度在250度和450度之間，化性和電性能夠被良好的控制。由實驗得知，在40度下成長，加入氨水反應，最後在350度下退火的液相沉積法氟氧化矽可以得到最佳的電性。介電常數可以低至3.2，在1.5 MV/cm下的漏電流密度可以降低到1×10-7 A/cm2。本研究的結果顯示，用液相沉積法加入氨水成長的氟氧化矽，經過退火的處理後，可以做為在兩金屬導線間介電層的材料。

With increasing integration density of very large scale integrated (VLSI) devices, multilevel metallization technology is becoming more important than it used to be. In advanced logic devices, the interlayer dielectrics have increased to four or five layers. Silicon oxide films are used as interlayer film. One candidate for making interlayer film with a low dielectric constant is F-doped Silicon oxide (SiOF). Such films have a low dielectric constant and that moisture absorption is the main drawback in using this material. For this reason, we intend to dehydrate the SiOF films by thermal annealing treatment. It could improve the electrical properties of oxide films and obtain a reliable film with lower dielectric constant.
This is our purpose in this paper to explore the electrical and chemical properties of LPD-SiOF films with annealing treatment. The chemical and electrical properties can be controlled well within 250 ~ 450 ℃ annealing treatment. The LPD-SiOF film deposited at 40 ℃ with 0.8 M NH4OH incorporation and 350 ℃ annealing treatment obtain the best electrical results. The dielectric constant can drop to about 3.2, and the leakage current density can be improved to about 1×10-7 A/cm2 under 1.5 MV/cm. Results of this study demonstrate that the SiOF films prepared by LPD with NH4OH incorporation followed by annealing treatment is suitable for IMD application.

CONTENTS I
LIST OF FIGURES IV
ABSTRACT VI

Chapter 1 Introduction 1
1-1 Background of Fluorinated Silicon Dioxide 1
1-2 Motivation of SiOF with Annealing Treatment 2
1-3 Background of TD-LPD-SiOF 3
1-4 Mechanisms of LPD-SiOF 3
1-5 Advantages of LPD 4

Chapter 2 MOS Theory 6
2-1 Charges and Traps in Oxide Film 6
2-2 Effective Oxide Charge and Interface Trap Charge Effects 6
2-3 Extraction of Interface Trap Properties from the Capacitance 8
2-4 High Frequency Capacitance Method 9
2-4 Measurement of Interface Trap Density 9

Chapter 3 Experiments 10
3-1 Liquid Phase Deposition System 10
3-2 Deposition Procedures 11
3-2-1 Si Wafer Cleaning Procedures 11
3-2-2 Preparation of Deposition Solution 11
3-2-3 Film Growth 12
3-3 Annealing Treatment 13
3-4 Fabrication of MOS Structure 13
3-5 Characteristics 14
3-5-1 Physical and Chemical Properties 14
3-5-2 Electrical Properties 14

Chapter 4 Results and Discussion 16
4-1 Physical Properties of LPD-SiOF Film 16
4-1-1 Deposition of LPD-SiOF Film 16
4-1-2 SEM View of LPD-SiOF Film 16
4-2 Chemical properties of LPD-SiOF Film 17
4-2-1 Analysis of XPS Spectra 17
4-2-2 AES Survey Scan and Depth Profile 18
4-2-3 Analysis of FTIR Spectra 18
4-2-4 Increment of F Content in LPD-SiOF Film 21
4-3 Model of Chemical Reaction for Deposition Mechanism 22
4-4 Model of Annealed LPD-SiOF Mechanism 23
4-5 Electrical Properties of LPD-SiOF Film 24
4-5-1 The C-V Characteristics for LPD-SiOF Film Annealed at Various Temperature 24
4-5-2 The J-E Characteristics for LPD-SiOF Film Annealed at Various Temperature 25
4-5-3 Dielectric Constant Relationship of LPD-SiOF Film with Annealing Treatment 26
4-5-4 Interface Trap Density Relationship of LPD-SiOF Film with Annealing Treatment 26
4-5-5 Summary 27

Chapter 5 Conclusions 29

REFERENCES 31~36
FIGURES 37~66

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