Low- k Dielectric Film Patterning by X-Ray Lithography

2005

SPIE Proceedings

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Characteristics of photosensitive low-k methylsilsesquioxane (MSQ) were investigated by use of electron-beam lithography. Photosensitive low-k MSQ makes it possible to realize via and trench patterns for Cu damascene technology in the ultra-large-scale-integrated (ULSI) circuit multilevel interconnect integration without dryetching processes. In this paper the dependences of exposure dose, humidification treatment and development method on critical dimension were investigated. It is found that longer humidification treatment resulted in the lower critical exposure dose, while the feature sizes were enlarged. The feature sizes had a linear correlation with exposure dose. Then reduction of the critical exposure dose minimizes the feature sizes. The development with ultrasonic wave was developed to reduce the critical exposure dose for 100 nm line and space pattern with the aspect ratio 3.3.

Section: Introductionmentioning

confidence: 99%

Photosensitive porous low-k interlayer dielectric film

2005

SPIE Proceedings

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“…It is necessary to reduce the total process cost so that photosensitive porous low-k dielectric films should be developed. Feasibility study of photosensitive non-porous low-k methylsilsesquioxane (MSQ) were carried out by using ultra-violet, KrF excimer laser, electron beam and SOR X-ray lithographies [1][2][3]. In this paper, a novel photosensitive porous MSQ film was developed and its characteristics were investigated.…”

Section: Introductionmentioning

confidence: 99%

A Novel Photosensitive Porous Low-k Interlayer Dielectric Film

Sakamoto

2004

Jpn. J. Appl. Phys.

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We derive expressions for the Ricci curvature tensor and scalar in terms of intrinsic torsion classes of half-flat manifolds by exploiting the relationship between halfflat manifolds and non-compact G 2 holonomy manifolds. Our expressions are tested for Iwasawa and more general nilpotent manifolds. We also derive expressions, in the language of Calabi-Yau moduli spaces, for the torsion classes and the Ricci curvature of the particular half-flat manifolds that arise naturally via mirror symmetry in flux compactifications. Using these expressions we then derive a constraint on the Kähler moduli space of type II string theories on these half-flat manifolds.

“…Then the lithography of photosensitive low-k MSQ was examined by using an ultraviolet light, KrF excimer laser, electron beam, and silicon-onruby ͑SOR͒ X-ray. [3][4][5] In these lithographies via and trench patterns were formed directly in the MSZ film without using dry etching, however the tapered shape of exposed patterns was formed. At the same time in the KrF lithography, the standing waves between the substrate and the MSZ surface caused the nonflat sidewalls in the trench patterns.…”

mentioning

confidence: 99%

Characterization of Photosensitive Low-k Films Using Electron-Beam Lithography

2005

J. Electrochem. Soc.

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Characteristics of photosensitive low-k methylsilsesquioxane ͑MSQ͒ were investigated by the use of electron-beam lithography. Photosensitive low-k MSQ makes it possible to realize via and trench structures for Cu damascene technology without dry etching processes in the multilevel interconnect integration of ultralarge scale-integrated circuits. In this paper the dependences of critical dimensions of developed patterns on exposure dose and hold time after exposure were investigated. Consequently the aspect ratio of the developed trench structure of 3.9 and the minimal feature size of 90 nm were achieved.According to the scaling rule 1 for miniaturization of the ultralarge-scale integrated circuits ͑ULSI͒, the interconnect feature sizes of lines and spaces should be reduced. The increase of interconnect resistance-capacitance ͑RC͒ delay occur as the reverse effect due to the scaling down. Therefore, the interconnect technologies with low-resistance metal wire and low-dielectric constant ͑low-k͒ interlayer film are needed for ULSI. Furthermore, the application of low-k dielectric to the interlayer dielectric film can reduce power consumption of ULSIs.Methylsilsesquioxane ͑MSQ͒ has been developed as a low dielectric constant material; k = 2.7. 2,3 Methylsilsesquiazane ͑MSZ͒ is a precursor component of MSQ as shown in Fig. 1. When the photoacid generator ͑PAG͒ molecule is added to MSZ, it acquires photosensitivity. The photosensitive MSZ precursor has sensitivity to not only ultraviolet light, but also to an electron beam ͑EB͒. Then the lithography of photosensitive low-k MSQ was examined by using an ultraviolet light, KrF excimer laser, electron beam, and silicon-onruby ͑SOR͒ X-ray. [3][4][5] In these lithographies via and trench patterns were formed directly in the MSZ film without using dry etching, however the tapered shape of exposed patterns was formed. At the same time in the KrF lithography, the standing waves between the substrate and the MSZ surface caused the nonflat sidewalls in the trench patterns. 4 Thus improvement of the exposed pattern was required.The dry etch-less process eliminates the resist coating and ashing, so that it can reduce process steps. Furthermore, the reliability issues such as void formation in the film due to dry etching and ashing 6 can be eliminated. At the same time disuse of the hardmask and etch-stop layer enables us to reduce the effective dielectric constant of the multilevel interconnect interlayer. ExperimentalE-beam exposure experiments of photosensitive low-k films were carried out using triazine radical TAZ-100 PAG ͑Midori Kagaku͒ as shown in Fig. 2a. The possible chemical reaction for TAZ-100 in photosensitive MSZ is shown in Fig. 2b. 7 The photosensitive MSZ precursor was spin-coated to a thickness of 350 nm on 2 in. Si͑100͒ wafers at 2000 rpm for 20 s. It was prebaked at 90°C for 1 min. The humidification of the film was carried out after the EB lithography in the posthumidification process. The EB lithography was performed by use of an Hitachi HL-700 electron-beam s...