摘要:

A new step‐and‐repeat x‐ray exposure system has been developed to establish practical submicron x‐ray lithography. Penumbra and run‐out error have been determined on the basis of resolution consideration and alignment accuracy analysis. The fundamental system parameters have been derived for constructing an efficient and accurate exposure system. To realize such a system, certain new technologies have been developed. (1) A high power Si–Kα x‐ray source brings a large x‐ray flux onto the wafer through a silicon nitride mask membrane. (2) The optical mark and gap detection method is connected to a precise alignment mechanism placed on anx–ytable designed for wafer stepping. (3) This construction ensures atmospheric environment exposure. (4) The exposure system operation is fully automatic thanks to microprocessors. A 0.5 μm pattern has been accurately replicated, and a ±0.15 μm alignment accuracy has been achieved using this exposure system.

ISSN:0734-211X    

DOI:10.1116/1.582942

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

In order to fabricate submicrometer‐channel‐length MOSFET’s using x‐ray lithography, a novel mask fabrication technique was developed. The mask enabled PMMA lines with widths of 100, 160, 250, 270, and 5000 nm to be exposed simultaneously on the same substrate. The mask consists of a polyimide membrane with narrow absorber lines on the front side (facing the substrate) and coarse absorber patterns on the back side (facing the x‐ray source). The narrow absorber lines are formed by oblique shadowing of gold onto sidewalls of rectangular mesas molded on the polyimide from wells anisotropically etched in (110)Si. As a result, exposed lines are straight, controlled in width to ∼10%, and have very small edge ripple. Source and drain pattern areas are formed in gold on the back surface of the membrane by conventional photolithography and ion beam etching. PMMA lines exposed with the x‐ray mask were used for channel masking during source–drain ion implantation. Operating MOSFET’s were fabricated with minimum channel length estimated to be 75 nm.

ISSN:0734-211X    

DOI:10.1116/1.582943

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

Thin films of amorphous phosphorus decaselenide (P4Se10) have been explored for lithographic applications. Depending on the substrate temperature during plasma etching in CF4gas, either positive or negative resist behavior is observed. The effects of substrate temperature and exposure time on etching characteristics are discussed. Contrast values of 2.5 and 2.9 for positive and negative resist, respectively, have been obtained.

ISSN:0734-211X    

DOI:10.1116/1.582944

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

Pattern profiles achieved in composite resists of a polymer and a bisazide compound tend to be rectangular, in spite of electron backscattering from substrates. This phenomenon is explained by the bisazide concentration dependence of the composite resist sensitivity to electron beam and the depth profile of bisazide distribution in a polymer film. An optimum amount of bisazide compound, needed to obtain the highest sensitization, exists. It does not depend on molecular weight, but on the kind of polymers used. An excessive amount of bisazide compound incorporation is found to reduce sensitivity. Bisazide compounds distribute to a great extent in the vicinity of a substrate during a prebaking process. These factors reduce the backscattering problem taking place in electron beam lithography to obtain resist patterns with vertical walls.

ISSN:0734-211X    

DOI:10.1116/1.582945

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

Two optical probes, utilizing laser‐induced biacetyl phosphorescence recorded by an image‐intensified solid state camera, have been developed and used to characterize velocity fields in a low pressure chamber (similar to a plasma‐enhanced CVD reactor). The method has been demonstrated at pressures as low as 0.5 Torr; measurements at lower pressures should be possible. Reactor flow velocity fields influence gas residence times and deposition rates. The method discussed in this paper can be used to investigate these effects.

ISSN:0734-211X    

DOI:10.1116/1.582946

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

Silicon oxide films formed using two different chemical vapor deposition (CVD) techniques have been characterized by selected etching properties, both in dry (plasma) etching and in wet (chemical) etching. Dry etching was accomplished using CHF3+O2in a reactive ion etching (RIE) system. The films investigated are undoped silicon oxide, phosphorus‐doped silicon oxide at 4 mol % P2O5, and phosphorus‐doped silicon oxide at 9.5 mol % P2O5. The effects of densification, i.e., thermal treatments carried out at 900 °C in an inert atmosphere (N2) and at 920 °C in steam, are discussed in detail. A decrease in etch rate is observed and considered to be an indication of the structural changes that lead to less porous and more stable films.

ISSN:0734-211X    

DOI:10.1116/1.582947

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

The effect of CF4+O2plasma on GaAs is studied using Auger electron spectroscopy and x‐ray photoelectron spectroscopy. AES sputtering profiles and the chemical shift in the Ga 3dphotoelectron peak indicate the Ga2O3‐rich oxide formation on the GaAs surface through exposure to CF4+O2plasma. The increase in the Schottky diode ideality factornand the decrease in GaAs MESFET transconductancegmas functions of plasma exposure time are explained with this oxide formation. The GaAs MESFETI–Vcharacteristics are improved by removing the Ga2O3‐rich oxide layer with chemical treatment.

ISSN:0734-211X    

DOI:10.1116/1.582948

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

Basic chemical processes in a CF4/O2plasma during etching of silicon nitride have been investigated using mass spectrometry. Samples of the discharge are extracted through a quartz capillary and the resulting variations in species abundance at a nitride/oxide interface yield information on etch reaction pathways. Mechanisms of F and CF2attack and SiF4, N2, NO, and CN product formation are proposed. The experimental data are suitable for application in mass spectrometric endpoint detection.

ISSN:0734-211X    

DOI:10.1116/1.582949

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

Silicon dioxide patterns having vertical sidewalls have been obtained without pattern width loss by reactive ion etching in CF4. The polymerization effect, caused by fluorine deficiency in the plasma, is found to influence not only the morphology of the etched resist surface but also the SiO2etching profiles. The polymerization is greatly reduced by depressing the temperature rise during etching. A temperature‐controlled cathode and a heat sink material are used for this purpose. The polymerization is further reduced by increasing flow rate, by increasing pressure and by decreasing power density. The SiO2patterns having vertical sidewalls are obtained under the no‐polymerization etching conditions. These SiO2patterns have been successfully applied to ion‐implantation masks for 16 Mbit bubble devices.

ISSN:0734-211X    

DOI:10.1116/1.582950

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

The vapor of the organic halide, ethylene dibromide (EDB), was used for InPinsituetching. The etching process was carried out in a low pressure (≂50 Pa) flowing system. A two‐zone resistance‐heated furnace was employed such that EDB molecules were decomposed to yield a more reactive form of bromine in the high temperature zone, whereas the substrate was placed in the low temperature zone to avoid thermal degradation of the InP. Surfaces as specular as before etching were obtained by using this technique. The process was studied for substrate temperatures between 120 and 540 °C and for hot zone temperatures between 600 and 900 °C. The etch rate varied between 0.002 and 1.0 μm/min depending on the furnace temperature and the EDB flow rate.

ISSN:0734-211X    

DOI:10.1116/1.582951

出版商:American Vacuum Society    

年代:1985

数据来源: AIP