摘要:

This article describes a near-field photolithographic method that uses an elastomeric phase mask in conformal contact with photoresist. The method is capable of generating∼90 nmlines in commercially available photoresist, using broadband, incoherent light with wavelengths between 330 and 460 nm. Transfer of these patterns into silicon dioxide and gold demonstrates the integrity of the patterned resist.

ISSN:1071-1023    

DOI:10.1116/1.589836

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

Linewidth fluctuation of resist patterns is a serious problem in fabricating nanodevices when lithographic resolution is improved to the nanometer scale. As a resist material for reducing linewidth fluctuations, we evaluate hydrogen silsesquioxane (HSQ) with a three-dimensional framework from the standpoints of resist patterning and its ability to reduce linewidth fluctuation. Infrared analyses indicate that SiH bonds in HSQ are broken by electron-beam irradiation, and consequently, the crosslinking required for negative tone patterning is generated. By applying a TMAH developer suitable for the dissolution of the siloxane bonds in HSQ, we improve contrast and reduce the thickness loss of the lightly exposed resist area. In addition, the HSQ resist has relatively high sensitivity for resist materials without any reactive groups. The etching durability sacrificed for the attainment of high sensitivity is improved by oxygen plasma treatment. No damage, such as pattern-shape deformation after the oxygen plasma treatment, is observed. Linewidth fluctuation due to edge roughness of resist patterns results from aggregates in the resist polymer. Aggregates in HSQ are small owing to its three-dimensional framework. In addition, the excellent development property of HSQ avoids any influence from polymer aggregates on development. Consequently, linewidth fluctuation can be reduced to less than 2 nm. This leads to a decrease in the variation of gate capacitance in single-electron transistors.

ISSN:1071-1023    

DOI:10.1116/1.589837

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

We report on the fabrication of metallic nanostructures in the sub-100 nm region by means of electron-beam lithography with metal colloids. A thin organometallic film consisting of surfactant stabilized Pd-colloids(⩽3 nm) is directly patterned by electron-beam irradiation. Non-exposed colloids are easily removed by rinsing the sample with appropriate dissolvers. The metallic character of the nanostructures is checked by resistance measurements. We find the morphology and the resistance behavior of the present nanostructured Pd-colloids to be similar to those of granular thin Pd/C films. Accordingly, the metal content of the nanostructures fabricated with Pd-colloids can be estimated.

ISSN:1071-1023    

DOI:10.1116/1.589838

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

The effort discussed here addresses the use of shorter incident wavelengths for characterizing sub-0.1 μm linewidths and the corresponding influence on scatterometry measurement sensitivity to linewidth variations. A sensitivity metric, based on the variance statistic, was developed using well-characterized, large-pitch (0.80 μm) photoresist grating structures on Si illuminated at 633 and 442 nm. The same metric was applied to short-pitch (0.20 μm), etched gratings on InP, with the result that appreciable scatterometry sensitivity was measured, even at the 633 nm incident wavelength. Modeling was used to estimate scatterometry sensitivity at three wavelengths for photoresist critical dimensions of 100 and 70 nm on Si. A significant increase in sensitivity was not found until the incident wavelength was reduced to 325 nm. We are presently investigating techniques to improve measurement sensitivity for short-pitch structures using the 633 nm incident wavelength.

ISSN:1071-1023    

DOI:10.1116/1.589840

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

This article describes a moiré technique for determining distortions in soft lithography. We use the technique to investigate distortions when soft lithography is performed in a variety of configurations; a method is identified for limiting maximum distortions to less than 1μm over areas∼1 cm2. We also suggest an approach for actively controlling these distortions, and we demonstrate in a simple way its feasibility.

ISSN:1071-1023    

DOI:10.1116/1.589841

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

A new type of photomask was fabricated by casting a prepolymer of a transparent, elastomeric polymer (polydimethylsiloxane, PDMS) against a Si(100) master whose surface has been patterned with V-shaped trenches or pyramidal pits using anisotropic etching. The PDMS replica, when placed in contact with a film of photoresist and illuminated, acts as a photomask. The sidewalls of the trenches and pits in the silicon master meet with the plateaus in dihedral angles of 54°; as a result, the PDMS replica selectively blocks the incident light in regions where it has sloping features by total internal reflection, and acts as a reflective contact mask for photolithography. The feasibility of this new type of photomask has been demonstrated by the fabrication of micropatterns in photoresist (and in an underlying silicon substrate) with smaller feature sizes and higher complexities than those present on the original chrome mask used in patterning the silicon master. The patterns produced using these elastomeric photomasks can be changed by varying the pressure applied in contacting them.

ISSN:1071-1023    

DOI:10.1116/1.589842

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

An electrostatic lens, operated in accel–decel mode, is presented. The lens has advantage of low chromatic aberration, which is about2/3the amount produced by a conventional einzel lens operated in decel mode. The lens has two pieces of electrodes built in to accelerate and decelerate the beam. The decelerating electrode works as a main lens, while the accelerating electrode enhances the beam energy, reducing the aberration. Calculations for the accel–decel lens provideCcof 22 mm andfof 10 mm with working distance of 5 mm. The lens is suitable for producing a fine beam with a smaller spot size and with energy of over a few tens of kiloelectron volts. When the lens is applied to a 30 keV focused ion beam with 1 pA current, the spot size is estimated as 4.8 nm in diameter on a target with the above working distance.

ISSN:1071-1023    

DOI:10.1116/1.589762

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

A mathematical model for sputtering a shape or cavity with an arbitrary cross-sectional profile has been developed for focused ion beam milling. The ion beam is assumed to have a Gaussian intensity distribution and a submicron width. The model solves for ion beam dwell times on a pixel grid which yields the desired feature depth as a function of the pixel(x,y)coordinate. The solution is unique and accounts for the ion beam flux contribution at any point from all other pixels in the address matrix. A semiempirical sputter yield treatment allows for a very wide range of ion beam/solid combinations and for yield variations with ion energy and angle of incidence. Solutions have been obtained for parabolic surfaces of revolution, a parabolic trench (with a plane of symmetry) and a hemispherical pit. Either a square or a circular pixel matrix was used for the parabolic shapes. Correspondence between the predictions of the model and experimental 20 keVGa+sputtering of a parabolic cross-section trench in Si(100) was within the limits of the accuracy of the experimental control.

ISSN:1071-1023    

DOI:10.1116/1.589763

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

We have performed a theoretical investigation of two-dimensional effects in melting and arsenic gas immersion laser doping of unpatterned silicon under patterned excimer-laser exposure. For pattern sizes below a few microns, the melt depths depend on the pattern size, rendering processing of narrow and wide features with the same laser fluence difficult. For wide exposed areas, molten regions are significantly narrower than the exposed widths, particularly for lower fluences. For deep submicron unexposed spaces, the melt may encroach into unexposed areas, potentially melting through them for higher fluences. Raising concerns regarding the processing of unpatterned wafers, these results indicate that structures on patterned wafers should be exploited to control thermal diffusion effects.

ISSN:1071-1023    

DOI:10.1116/1.589764

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

Poly(vinylidene fluoride-co-trifluoroethylene) [P(VDF/TrFE), VDF 75 mol %] ultrathin films of 10 nm thickness were prepared on gold coated silicon wafer substrates by a spin-coating method and their aggregation states were investigated by Fourier transform infrared reflection absorption spectroscopic measurement. It was found that P(VDF/TrFE) formed a ferroelectric phase even in a confined state such as an ultrathin film. The electric field was locally imposed on the ultrathin film through a gold coated cantilever tip. The change of dipole moment orientation of P(VDF/TrFE) was evaluated by measuring surface potential change, performed by scanning Maxwell stress microscopy (SMM). The SMM images revealed that the local dipole moment orientation of P(VDF/TrFE) in ultrathin films could be changed by an application of electric field through an atomic force microscope tip.

ISSN:1071-1023    

DOI:10.1116/1.589765

出版商:American Vacuum Society    

年代:1998

数据来源: AIP