Enhanced dielectric-constant reliability of low-k porous organosilicate glass (k--2.3) for 45-nm-generation cu interconnects

AbstractWe present here a method for fabrication of air-gaps between Cu-interconnects to achieve low intralevel dielectric constant, using a sacrificial polymer as a ‘place holder’. IC compatible metallization and CMP processes were used in a single damascene process. The air-gap occupies the entire intralevel volume between the copper lines with fully densified SiO2 as the planer interlevel dielectric. The width of the air-gaps was 286 nm and the width of the copper lines was 650 nm. The effective intralevel dielectric constant was calculated to be 2.19. The thickness of the interlevel SiO2 and copper lines were 1100 nm and 700 nm, respectively. Further reduction in the value of intralevel dielectric constant is possible by optimization of the geometry of the metal/air-gap structure, and by use of a low k interlevel dielectric material.In this method of forming air-gaps, the layer of sacrificial polymer was spin-coated onto the substrate and formed into the desired pattern using an oxide or metal mask and reactive-ion-etching. The intralevel Cu trench is then inlaid using a damascene process. After the CMP of copper, interlevel SiO2 is deposited by plasma-CVD. Finally, the polymer place-holder is thermally decomposed with the decomposition products permeating through the interlevel dielectric material. The major advantages of this method over other reported methods of formation of air-gaps are excellent control over the geometry of the air-gaps; no protrusion of air-gaps into the interlevel dielectric; no deposition of SiO2 over the side-walls, and no degradation of the interlevel dielectric during the formation of air-gap.

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Plasma Enhanced Chemical Vapor Deposition of Porous Organosilicate Glass ILD Films With k ≤ 2.4.

MRS Proceedings ◽

10.1557/proc-766-e7.4 ◽

2003 ◽

Vol 766 ◽

Cited By ~ 9

Author(s):

Raymond N. Vrtis ◽

Mark L. O'Neill ◽

Jean L. Vincent ◽

Aaron S. Lukas ◽

Brian K. Peterson ◽

...

Keyword(s):

Dielectric Constant ◽

Chemical Vapor Deposition ◽

Mechanical Strength ◽

Thermal Annealing ◽

Vapor Deposition ◽

Chemical Vapor ◽

Organosilicate Glass

AbstractWe report on our work to develop a process for depositing nanoporous organosilicate (OSG) films via plasma enhanced chemical vapor deposition (PECVD). This approach entails codepositing an OSG material with a plasma polymerizable hydrocarbon, followed by thermal annealing of the material to remove the porogen, leaving an OSG matrix with nano-sized voids. The dielectric constant of the final film is controlled by varying the ratio of porogen precursor to OSG precursor in the delivery gas. Because of the need to maintain the mechanical strength of the final material, diethoxymethylsilane (DEMS) is utilized as the OSG precursor. Utilizing this route we are able to deposit films with a dielectric constant of 2.55 to 2.20 and hardness of 0.7 to 0.3 GPa, respectively.

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Structire, Properties, and Process Characteristics of Low-K Materials Prepared by PECVD

MRS Proceedings ◽

10.1557/proc-565-255 ◽

1999 ◽

Vol 565 ◽

Author(s):

Y. Shimogaki ◽

S. W. Lim ◽

E. G. Loh ◽

Y. Nakano ◽

K. Tada ◽

...

Keyword(s):

Growth Rate ◽

Dielectric Constant ◽

Gas Flow ◽

Structural Changes ◽

Silicon Oxide ◽

Reactive Species ◽

Low Dielectric Constant ◽

Low Dielectric ◽

Step Coverage ◽

Low K

AbstractLow dielectric constant F-doped silicon oxide films (SiO:F) can be prepared by adding fluorine source, like as CF4 to the conventional PECVD processes. We could obtain SiO:F films with dielectric constant as low as 2.6 from the reaction mixture of SiH4/N2 O/CF4. The structural changes of the oxides were sensitively detected by Raman spectroscopy. The three-fold ring and network structure of the silicon oxides were selectively decreased by adding fluorine into the film. These structural changes contribute to the decrease ionic polarization of the film, but it was not the major factor for the low dielectric constant. The addition of fluorine was very effective to eliminate the Si-OH in the film and the disappearance of the Si-OH was the key factor to obtain low dielectric constant. A kinetic analysis of the process was also performed to investigate the reaction mechanism. We focused on the effect of gas flow rate, i.e. the residence time of the precursors in the reactor, on growth rate and step coverage of SiO:F films. It revealed that there exists two species to form SiO:F films. One is the reactive species which contributes to increase the growth rate and the other one is the less reactive species which contributes to have uniform step coverage. The same approach was made on the PECVD process to produce low-k C:F films from C2F4, and we found ionic species is the main precursor to form C:F films.

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Electromigration failure mode concerning negative resistance shift of Cu interconnects buried in porous low-k dielectric

Applied Physics Letters ◽

10.1063/1.4976738 ◽

2017 ◽

Vol 110 (8) ◽

pp. 083502 ◽

Cited By ~ 2

Author(s):

Hui Zheng ◽

Binfeng Yin ◽

Hewei Yu ◽

Leigang Chen ◽

Lin Gao ◽

...

Keyword(s):

Failure Mode ◽

Negative Resistance ◽

Cu Interconnects ◽

Low K

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The characterization and preparation of porous low dielectric films using various cyclodextrins as template materials

MRS Proceedings ◽

10.1557/proc-766-e8.10 ◽

2003 ◽

Vol 766 ◽

Cited By ~ 7

Author(s):

Jin-Heong Yim ◽

Jung-Bae Kim ◽

Hyun-Dam Jeong ◽

Yi-Yeoul Lyu ◽

Sang Kook Mah ◽

...

Keyword(s):

Thin Film ◽

Mechanical Properties ◽

Dielectric Constant ◽

Pore Structure ◽

Pore Diameter ◽

Dielectric Films ◽

Low Dielectric Constant ◽

Cyclodextrin Derivatives ◽

Low Dielectric ◽

Low K

AbstractPorous low dielectric films containing nano pores (∼20Å) with low dielectric constant (<2.2), have been prepared by using various kinds of cyclodextrin derivatives as porogenic materials. The pore structure such as pore size and interconnectivity can be controlled by changing functional groups of the cyclodextrin derivatives. We found that mechanical properties of porous low-k thin film prepared with mCSSQ (modified cyclic silsesquioxane) precursor and cyclodextrin derivatives were correlated with the pore interconnection length. The longer the interconnection length of nanopores in the thin film, the worse the mechanical properties of the thin film (such as hardness and modulus) even though the pore diameter of the films were microporous (∼2nm).

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Impact of low-k dielectrics and barrier metals on TDDB lifetime of Cu interconnects

2001 IEEE International Reliability Physics Symposium Proceedings. 39th Annual (Cat. No.00CH37167) ◽

10.1109/relphy.2001.922927 ◽

2002 ◽

Cited By ~ 12

Author(s):

J. Noguchi ◽

T. Saito ◽

N. Ohashi ◽

H. Ashihara ◽

H. Maruyama ◽

...

Keyword(s):

Cu Interconnects ◽

Low K

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Sol–gel deposited xerogel, aerogel and porogen based porous low-k thin films: A comparative investigation

International Journal of Modern Physics B ◽

10.1142/s0217979221400191 ◽

2021 ◽

pp. 2140019

Author(s):

Swati Gupta ◽

Anil Gaikwad ◽

Ashok Mahajan ◽

Lin Hongxiao ◽

He Zhewei

Keyword(s):

Dielectric Constant ◽

Sol Gel ◽

Comparative Investigation ◽

Crosstalk Noise ◽

Nanoelectronic Devices ◽

Low Dielectric ◽

Interconnect Delay ◽

Xerogel Films ◽

Low K ◽

Porosity Percentage

Low dielectric constant (Low-[Formula: see text]) films are used as inter layer dielectric (ILD) in nanoelectronic devices to reduce interconnect delay, crosstalk noise and power consumption. Tailoring capability of porous low-[Formula: see text] films attracted more attention. Present work investigates comparative study of xerogel, aerogel and porogen based porous low-[Formula: see text] films. Deposition of SiO2 and incorporation of less polar bonds in film matrix is confirmed using Fourier Transform Infra-Red Spectroscopy (FTIR). Refractive indices (RI) of xerogel, aerogel and porogen based low-[Formula: see text] films observed to be as low as 1.25, 1.19 and 1.14, respectively. Higher porosity percentage of 69.46% is observed for porogen-based films while for shrinked xerogel films, it is lowered to 45.47%. Porous structure of low-[Formula: see text] films has been validated by using Field Emission Scanning Electron Microscopy (FE-SEM). The pore diameters of porogen based annealed samples were in the range of 3.53–25.50 nm. The dielectric constant ([Formula: see text]) obtained from RI for xerogel, aerogel and porogen based films are 2.58, 2.20 and 1.88, respectively.

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