&lt;title&gt;Novel surface imaging masking technique for high-aspect-ratio dry etching applications&lt;/title&gt;

Calabrese, Gary S.; Abali, Livingstone N.; Bohland, John F.; Pavelchek, Edward K.; Sricharoenchaikit, Prasit; Vizvary, Gerald; Bobbio, Stephen M.; Smith, P.

doi:10.1117/12.46401

Cited by 3 publications

(4 citation statements)

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“…Nickel is known to have superior etch resistance to Cu because the nickel halide species formed during plasma etching are much less volatile than those of copper. Etching studies have indicated that thin electroless Ni films exhibit etch selectivity of over 300:1 for photoresist (11). We have found a 400 A electroless Ni layer to be essentially unaffected during a 3.5 min RIE under conditions that yield an etch rate of 100/~/min for S i Q etch rate and 1000/~Jmin for poly-Si.…”

Section: Pattern Transfermentioning

confidence: 92%

“…For example, a crystal with a higher carbon content than another crystal may show less thermal history effects. Because carbon enhances oxygen precipitation (11). Whether or not the thermal history will show in the wafers after a heat cycle also depends on the initial interstitial oxygen content, [ It has been proposed by Shimura (13) and shown by Fraundorf et al (5) that the thermal history effect can be erased to a large extent by a high temperature treatment, 1320~ h. In this paper, it will be shown that a very short high temperature rapid thermal preannealing process (RTP), 1200~ min in argon, can reduce the thermal history effect of a subsequent two-step heat treatment by lowering the seed-end precipitation to the same level as the tang-end precipitation.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…During 02 plasma etching, the silylated regions are converted to an SiO2-1ike material that serves as the actual etch barrier. In another process (11), a DNQ-novolak photoresist is exposed, then * Electrochemical Society Active Member. treated with a colloidal catalyst.…”

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confidence: 99%

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Deep Ultraviolet Lithography of Monolayer Films with Selective Electroless Metallization

Calvert

Chen

Dulcey

et al. 1992

J. Electrochem. Soc.

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A top surface imaging approach for the fabrication of submicron features on solid substrates has been developed. A monolayer film is exposed to patterned deep ultraviolet radiation, then selectively metallized using electroless deposition such that a thin metal layer (200-400 A) is deposited only in the unexposed areas. The film/metal assembly is a highly effective mask for reactive ion etching which can subsequently be stripped from the substrate after feature definition. Features with 0.3 t~m line width in polysilicon and working transistor test structures have been produced using this process.In considering the characteristics of an ideal imaging process for optical lithography, numerous factors must be taken into account (1). The well-known Rayleigh criterion [1] states that the minimum resolution or feature width (W) is directly proportional to the exposure wave length (X), a material specific k factor, and inversely proportional to the numerical aperture (NA) of the lensOptical lithography is progressing from g-line (436 nm) to i-line (365 nm) to deep UV (248 nm and 193 nm) exposure tools in order to meet the continuing demand for greater circuit density, which requires smaller feature sizes. A second measure of lithographic performance, the modulation transfer function (MTF), is maximized as both wavelength and imaging layer thickness decrease. However, the depth of focus (DOF) is also directly proportional to wavelength, as given in Eq.[2]Short wavelength sources and high NA lenses which are desirable for fine feature printing can result in DOFs that are too small to produce a focussed image in a typical 1.0-1.5 i~m thick photoresist.There are additional difficulties with changing to shorter wavelength. Many photoresists are highly absorbing below about 250 nm. Alternate resins have been developed based on a limited class of materials that have sufficient transparency in the deep ultraviolet (UV). In addition, standing wave effects are particularly serious with deep UV lithography because of the higher reflectivity of silicon at these wavelengths. The use of antireflection coatings to solve this problem adds to the complexity of the lithographic processing (2).In the above analysis, the laws of optical physics lead to the conclusion that optimal performance will be obtained by the use of short wavelength irradiation and ultra-thin imaging layers. With a deep UV sensitive top surface imaging (TSI) process, resolution and MTF are maximized. If the layer is sufficiently thin, resist transparency is not a problem and standing waves can not be supported. DOF is also not an issue, except that a planarizing layer is required for printing over topography.The photoresist systems currently under the most active investigation are the DNQ-novolaks (3), chemically amplified resists (4, 5), and silicon containing polymer systems (6, 7). With the latter, photooxidation throughout at least several hundred Angstroms of the resist produces an oxidized silicon material that is resistant to certain plasmas for pattern trans...

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Section: Pattern Transfermentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Deep Ultraviolet Lithography of Monolayer Films with Selective Electroless Metallization

Calvert

Chen

Dulcey

et al. 1992

J. Electrochem. Soc.

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Resist Alternatives for Sub-0.35-μm Lithography Using Highly Attenuated Radiation

Kunz¹,

Hartney²,

Rothschild³

1992

Soft-X-Ray Projection Lithography

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Traditional optical lithography uses semitransparent single-layer resists where the exposing radiation produces a latent image throughout the thickness of the resist, and an isotropic liquid-based development step is used to create the desired resist profile. However, resolution of 0.25-μm or better, which is required for 256 Mbit DRAM chips and beyond, cannot be obtained with conventional photolithographic technology (250-400 nm wavelength). Shorter wavelengths are required, such as 193-nm (DUV-193), soft-X- ray (10-50 nm) or hard-X-ray (1-2 nm) radiation. Unfortunately, between the wavelengths of 10 and 220 nm few materials are semitransparent For example, at 193 nm novolac resins commonly used at longer wavelengths have an absorption depth of only 40 nm, and at the 13-nm wavelength it is 400 nm. New resist processes capable of accommodating a latent image confined to the near-surface region must therefore be developed. The lithographic process must now include an additional processing step, namely pattern transfer into the bulk of the resist. This step must be highly anisotropic so that the pattern in the surface layer is faithfully reproduced at the resist-substrate interface. These general considerations were outlined already in 1984 by Taylor et al.[1]. They apply also to other forms of strongly absorbed radiation such as ion beams. (For instance, a 30 keV Ga+ beam has a projected range of only 34 nm in photoresist.) Today, surface imaging processes have been demonstrated not only for soft X-ray projection (SXP) [2] and deep ultraviolet (DUV) lithographies [3], but are being considered for manufacturing processes at optical wavelengths as well [4]. In this paper we review some of the recent developments in the areas of surface imaging and multilayer resists, with emphasis on application to 193-nm lithography. It should be noted, however, that some of the reviewed resist concepts may be applicable to SXP lithography as well.

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X-Ray Fluorescence Determination of Low Metal Concentration in Surface Masking Layers on Organic Polymers

Hutton

Taylor

1991

MRS Proc.

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A highly sensitive x-ray fluorescence (XRF) technique has been developed for the determination of low metal concentrations in the etch resistant layer of surface-imaged photoresists. The samples may be analyzed quickly and the method is applicable to a wide variety of surfaceimaging processes. For each metal of interest the XRF spectrometer is easily calibrated using polymer films containing known concentrations of a metal-containing reagent. Examples of the application of this technique to the analysis of Ti, Si and Zr-containing films are described.

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<title>Novel surface imaging masking technique for high-aspect-ratio dry etching applications</title>

Cited by 3 publications

References 0 publications

Deep Ultraviolet Lithography of Monolayer Films with Selective Electroless Metallization

Deep Ultraviolet Lithography of Monolayer Films with Selective Electroless Metallization

Resist Alternatives for Sub-0.35-μm Lithography Using Highly Attenuated Radiation

X-Ray Fluorescence Determination of Low Metal Concentration in Surface Masking Layers on Organic Polymers

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