隨著半導體技術的進步，元件的尺寸不斷的縮小，而入深次微米的領域中。為了增加積體電路的性能，降低導線的線寬和增加金屬導線層的數目，便成為超大型積體電路技術所需採用的方式。然而電子訊號在金屬導線間傳遞所造成的延遲，變成半導體元件速度受限的主要原因。為了降低訊號傳遞的時間延遲，使用低介電常數材料作為導線間的絕緣層，便可降低導線間的電容值，使元件在速度方面的性能提高，並且可以降低功率的消耗(power dissipation)及雜訊干擾(cross-talk noise)。在眾多的低介電常數材料中，多孔性的二氧化矽(porous silica)薄膜，是其中極具發展潛力的一種材料。在本論文中，將對二氧化矽薄膜的物性、熱穩定性及電性進行探討。除此之外，在經過氧電漿的過程中會影響到材料的特性，我們也提供一些方法來改善氧電漿所帶來的問題。另外，我們使用碳氟氣體電漿對多孔隙二氧化矽薄膜進行蝕刻研究。

As IC technology moves into the deep submicrometer regime in high performance ULSI circuits, it is required to decrease the metal pitch and to increase the number of metal layers for interconnect to accommodate the increased packing density and functional complexity. But the signal propagation delay in the interconnect becomes an appreciable fraction of the total time delay. Use of low dielectric constant material (low-k) as the intermetal dielectric (IMD) results in low inter-line capacitance and therefore high performance in speed, low power dissipation, and low cross-talk noise. During various low dielectric materials, porous silica film is one of the possible candidates with an inherent low dielectric constant. In this thesis, the intrinsic properties such as fundamental physical, electrical, thermal stability of the spin on glass (SOG) have been investigated. We also study the properties of the SOG film with various plasma and treatments. An inherent low dielectric constant of 1.9 is achieved for high porosity of the porous silica film and the leakage current density keep at a level of ~10-9 A/cm2 at 1MV/cm electric field strength. After O2 plasma treatment, the Si-C and C-H bonds of the film are almost eliminated, thus the dielectric constant and leakage current are rapid increase than that of those untreated films. We find that H2 plasma can passivate the porous silica surface so that the leakage current can be kept at acceptable range, however, the dielectric constant increase slightly.
Moreover, the etching issues were also investigated in this study. The mask undercutting on sidewall was observed due to the spontaneous reaction between the porous silca film and fluorocarnbon plasma. Therefore, H2 plasma treatment was provided to suppress this phenomenon.
In this study, the intrinsic properties such as fundamental physical, electrical, and thermal properties of the porous silica have been investigated. The compatibility of the porous silica with integration processes also has been studied comprehensively. We have proposed H2 plasma treatments to improve the dielectric properties of porous silica after photoresist removal. Material and electrical analyses were used to interpret these improvements.

Chapter 1 Introduction
1.1 General background ……….…………..…..……..1
1.2 Motivation and Material options……...………......4
1.3 Organization of This Thesis……….….…….….…5

Chapter 2 Characteristics of Ultra Low Dielectric
Constant Porous Silica Spin-on Glass
2-1 Introduction………………………………………….7
2-2 Experimental Procedure……...………….………...8
2-3 Results and Discussion……….....……………..….9
2-3.1 Intrinsic Film Properties………………… 9
2-3.2 O2 plasma effect…………………………11
2-4 Summary…………………………………...…12

Chapter 3 Improvement of PR Stripping Characteristic on Porous film
3-1 Introduction…………….……………………………14
3-2 Experimental...……………………….……………..16
3-3 Results and Discussion…………………..………..19
3-3.1 H2 Plasma Treatment……..……………..19
3-3.2 NH3 Plasma Treatment…….....………....20
3-3.3 O2 Plasma Treatment……...……….…...21
3-3.4 H2 Plasma Treatment Followed by O2 Pla-
-sma Treatment………………………….. 22
3-4 Conclusion and Summary….…………………..…23

Chapter 4 Plasma Etching of Porous Silica
4-1 Introduction…………………………………………25
4-2 Experiment……………………………...…………..27
4-3 Results and Discussion.. ……...………………….28


Chapter 5 Conclusions and Suggestions for Future Work
5-1 Conclusions……………………………………..….31
5-2 Future Work……………………………………...…33

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