Characterization of patterned low-k film delamination during CMP for the 32nm node Cu/ultra low-k (k=1.6-1.8) integration

Yoo, Beom-Keun; Kondo, Shinya; Tokitoh, S.; Namiki, A.; Misawa, K.; Inukai, K.; Ohashi, N.; Kobayashi, Nozomu

doi:10.1109/iitc.2004.1345761

Cited by 4 publications

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“…It is reported that introduction of these porous low-k films in LSI fabrication brings difficulties and complexities due to their porous structure. [1][2][3][4][5][6][7][8][9][10][11][12] For example, delamination is reported to occur when copper on porous low-k dielectric is polished by chemical mechanical polishing ͑CMP͒. [6][7][8][9][10] Moreover, increase of dielectric constant is found when porous low-k dielectric is patterned by a dry etching process.…”

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confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12] For example, delamination is reported to occur when copper on porous low-k dielectric is polished by chemical mechanical polishing ͑CMP͒. [6][7][8][9][10] Moreover, increase of dielectric constant is found when porous low-k dielectric is patterned by a dry etching process. 11,12 Alternative nonporous polymer fluorocarbon is considered an indispensable ultralow-k dielectric to avoid such complexity for LSI fabrication.…”

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confidence: 99%

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Effect of Additives in Organic Acid Solutions for Post-CMP Cleaning on Polymer Low-k Fluorocarbon

Nemoto

Teramoto

et al. 2009

J. Electrochem. Soc.

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The appropriate post-chemical mechanical polishing ͑CMP͒ cleaning solution for an advanced nonporous polymer, ultralow-k fluorocarbon film is proposed. While decrease in fluorine content measured by high-resolution X-ray photoelectron spectroscopy and increase in dielectric constant were observed after additives cleaning with oxalic acid, no significant change of fluorine content and dielectric constant were found after citric acid with different additives and acids without additives cleanings. This reveals that additives play an important role in degradation of the fluorocarbon film. An appropriate selection of additives is important to clean the fluorocarbon film in post-CMP cleaning in advanced large-scale integrated generations. To complete successful integration of the post-CMP cleaning on new dielectric materials such as nonporous low-k fluorocarbon film, an appropriate solution and additives should be carefully selected to avoid electrical degradation in subsequent process.As technology node progresses, low-k dielectrics have been developed to reduce resistance-capacitance delay in large-scale integrated ͑LSI͒ circuits. Porous materials are being implemented as an ultralow-k dielectric for advanced LSI devices. It is reported that introduction of these porous low-k films in LSI fabrication brings difficulties and complexities due to their porous structure. 1-12 For example, delamination is reported to occur when copper on porous low-k dielectric is polished by chemical mechanical polishing ͑CMP͒. 6-10 Moreover, increase of dielectric constant is found when porous low-k dielectric is patterned by a dry etching process. 11,12 Alternative nonporous polymer fluorocarbon is considered an indispensable ultralow-k dielectric to avoid such complexity for LSI fabrication. [13][14][15] Microwave excited plasma using the radial line slot antenna with a dual-shower-plate structure reactor was developed to achieve a very low electron temperature ͑around 1-2 eV͒. [13][14][15][16][17][18] In this new reactor, the deposited gases are supplied by a lower shower plate inserted in the diffusion plasma region. 13,15 The fluorocarbon film formed using the new reactor indicates not only a low dielectric constant but also low leakage current density, sufficient mechanical strength, strong adhesion, and good surface smoothness. 15 Therefore, the nonporous fluorocarbon film is proposed as the foreground ultralow-k film in advanced LSI devices. Although the fluorocarbon film is expected to be stable for its structural advantage, a damageless process is anticipated to avoid dielectric constants change in subsequent process steps. A low-damage physical vapor deposition process was applied to reduce damage on the fluorocarbon. 19 The CMP and post-CMP processes are also of concern with regard to damage.In the cleaning process for devices of the 100 nm node and beyond, an ultraclean surface must be achieved without using strong chemical or mechanical forces. 20 A key solution to prevent contaminant redeposition is to make the best use o...

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Effect of Additives in Organic Acid Solutions for Post-CMP Cleaning on Polymer Low-k Fluorocarbon

Nemoto

Teramoto

et al. 2009

J. Electrochem. Soc.

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“…Major problems are delamination caused by chemical mechanical planarization and drastic change in the dielectric due to pore-induced damage occurring in the wet cleaning and ashing processes. Since porous SiOCH occupies a lot of space in a film, it is fragile and readily absorbs any solutions or gases [1][2][3][4][5]. Moreover, Cu atoms easily diffuse into the SiOCH through pores.…”

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confidence: 99%

Large-radius neutral beam enhanced chemical vapor deposition process for non-porous ultra-low-k SiOCH

2014

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Pores in ultra-low-k carbon-doped silicon oxide (SiOCH) film have been a serious problem because they produce fragile film strength, with the film incurring damage from integration and diffusion of Cu atoms in thermal annealing. To address this problem, we developed a practical large-radius neutral beam enhanced CVD process to precisely control the film structure so as to eliminate any pores in the film. We used the process with dimethoxy-tetramethyl-disiloxane (DMOTMDS) as a precursor to form a SiOCH film on an 8-inch Si wafer and obtained a non-porous film having an ultra-low k-value of 2.2 with sufficient modulus (>10 GPa). Analyzing the film structure by experimental and theoretical techniques showed that symmetric polymethylsilaxane (PMS) chains were grown and cross-linked to each other in the film. This particular film did not incur any damage from acid or alkali solution or oxygen plasma. Furthermore, the dense film almost completely resisted Cu diffusion into it during thermal annealing.

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“…To meet the demands for high-speed operation and low-power consumption in ultralarge scale integrated circuits, ultralow-k (ULK) dielectric is increasingly required in Cu interconnects. 1 Degradation of the electrical and mechanical properties of the low-k dielectric film needs to be avoided for ULK dielectric integration during Cu damascene fabrication. [2][3][4] The chemical mechanical planarization (CMP) technique has been emerging as an indispensable processing technique to level out topographical steps created on an interconnect structure.…”

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“…14 In particular, ULK film with pores is reported to be so fragile that it is becoming difficult in post-CMP cleaning to achieve a great enough particle removal ability without generating defects or degradation of electrical properties. 1,3,4 The authors have reported effects of various cleaning solutions on the shear force of post Cu CMP cleaning. 12 In that report, These reveal that the contact of the brush with the wafer and fluid flow both play an important role in the shear force, and tribological and hydrodynamic studies are considered to be necessary to clarify the mechanism of shear force generation.…”

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Tribological Study of Brush Scrubbing in Post-Chemical Mechanical Planarization Cleaning in Non-porous Ultralow-k Dielectric∕Cu Interconnects

Nemoto

Teramoto

et al. 2011

J. Electrochem. Soc.

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Damage reduction during planarization is strongly required to avoid scratch generation and variation of electrical properties of low-k dielectrics that can lead to yield loss in an integrated circuit after implementation of an ultralow-k dielectric in Cu damascene interconnects. Three brush scrubbing conditions were found to realize high shear force for good particle removal. Having analyzed contact characteristics on an advanced non-porous ultralow-k dielectric fluorocarbon, brush scrubbing at a high rotation rate with a low down pressure is proposed to satisfy both sufficient particle removal efficiency and damage reduction during post chemical mechanical planarization cleaning. Tribological effects of down pressure and brush rotation rate on scratch and electrical properties of the ultralow-k fluorocarbon film are explored. To reduce the damage generated by the brush scrubbing process on the ultralow-k dielectric, it is important to make use of the effect of fluid flow by increasing the brush rotation rate at a low down pressure in advanced Cu interconnects in future.

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Characterization of patterned low-k film delamination during CMP for the 32nm node Cu/ultra low-k (k=1.6-1.8) integration

Cited by 4 publications

References 0 publications

Effect of Additives in Organic Acid Solutions for Post-CMP Cleaning on Polymer Low-k Fluorocarbon

Effect of Additives in Organic Acid Solutions for Post-CMP Cleaning on Polymer Low-k Fluorocarbon

Large-radius neutral beam enhanced chemical vapor deposition process for non-porous ultra-low-k SiOCH

Tribological Study of Brush Scrubbing in Post-Chemical Mechanical Planarization Cleaning in Non-porous Ultralow-k Dielectric∕Cu Interconnects

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