摘要:

Parameters which influence the etching of polyimide (PI) downstream of an O2–CF4–Ar microwave (MW) plasma were studied. Of particular importance is the influence of the ratio of atomic number densities O/F in the plasma and the gas flow velocity, which caused an almost linear increase in the etch rate within the investigated limits of the experiment. No measurable etching of PI was found downstream of an O2–Ar plasma, although the presence of oxygen atoms in the vicinity of the substrate was verified by the chemiluminescent reaction with NO. Similar to previously reported radio frequency plasma studies, a fluorinated layer at the surface of (PI) was formed by exposure of the substrate downstream of a fluorine‐rich O2–CF4–Ar MW plasma. Changing the plasma composition to the optimum etching conditions (an oxygen‐rich plasma of about 20% CF4) removed the fluorinated layer after a period of time. Etching then proceeded with an oxygenated layer at the surface. The reported experiments confirmed that the formation of a fluorinated layer, the removal of this layer, and the formation of an oxygenated one was caused only by the interaction of neutrals, without the influence of ion bombardment.

ISSN:1071-1023    

DOI:10.1116/1.584054

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

The effects of sample temperature and reactant flow rate on aluminum etching in BBr3and BBr3/Br2mixtures were investigated in a parallel‐plate plasma etcher. Etch samples were bonded to the electrode with conductive epoxy to promote thermal equilibrium. Results indicated that the reaction was gas phase controlled between 30 and 140 °C; above 140 °C, the gas phase limitation may be due to reactant adsorption while a product desorption limitation may exist below 30 °C. Transport limitations were encountered at reactant flow rates below 10 sccm.

ISSN:1071-1023    

DOI:10.1116/1.584055

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

The characteristics of a CCl2F2:He reactive ion etch are reported for use in selectively etching GaAs/AlGaAs heterostructures. The etch is performed at a pressure of 150 mTorr, with rf power of 0.5 W/cm2. Both He and CCl2F2flow rates are controlled to 10 sccm, with measured dc self‐bias of typically 125 V. The etch rate for GaAs is 1.8 μm/min, while the AlGaAs etch rate depends on the Al mole fractionxwith measured values of 150 Å/min atx=0.28 and 45 Å/min atx=0.5. The selectivity is 120 atx=0.28 and 420 atx=0.5. The etch shows an anisotropy between the 〈011〉 and the 〈011̄〉 directions. Measurements of the plasma impedance are reported as a function of pressure, power, and gas flow rate. From these measurements, the dc bias can be computed and is shown to give good agreement with the measured values. The plasma conditions are sensitive to the previous history of the chamber, but by preconditioning the chamber, the etch is readily reproduced.

ISSN:1071-1023    

DOI:10.1116/1.584056

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

The resist performance of polymethacrylonitrile (PMCN) was tested with respect to applications in x‐ray lithography by irradiating the polymer with x rays (λ: 0.2–1.5 nm) generated by the electron storage ring BESSY. Both radiation sensitivity and contrast were greatly improved by soaking the irradiated polymer films with a very weak solvent (e.g., diethylketone) prior to development. Fine structure features of 0.3 μm (lines and spaces) were obtained at exposure doses of about 200 mJ/cm2using a mixture of cyclohexanone,o‐xylene, and water (weight ratio 65:34:1) as developer. PMCN performed quite satisfactorily in anisotropically operating etch resistance tests using a CHF3/O2plasma. The ratio of etch rates for PMCN and SiO2was determined asRPMCN/RSiO2<0.8. The resist performance of PMCN was independent of the initial molecular mass and the initial molecular mass distribution of the polymer in the rangeM=1×105–2×106.

ISSN:1071-1023    

DOI:10.1116/1.584057

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

A new portable conformable masking (PCM) using excimer laser lithography has been developed. This method is characterized by the combination of poly(dimethylglutarimide) and the water‐soluble contrast enhanced material developed here and the use of KrF excimer laser exposure. Using this lithography, we obtained good resist pattern profiles and submicron region resolution by a very simple process.

ISSN:1071-1023    

DOI:10.1116/1.584058

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

ISSN:1071-1023    

DOI:10.1116/1.584059

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

ISSN:1071-1023    

DOI:10.1116/1.584060

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

X‐ray lithography with wavelengths between 0.2 and 5 nm provides both high‐structural resolution as good as 0.1 μm and a wide scope of advantages for the application in circuit production. Examples for this better process performance compared to optical techniques are: lower particle and dust sensitivity, applicability of simple single‐layer resist technique, high depth of focus without any influence of substrate material and chip topography, and presumably, the highest throughput of all lithography methods which are able to go into the submicron range. However, the introduction of x‐ray lithography into the semiconductor production means a revolutionary change of production technology. This begins with a completely different mask technology which makes, for example, the classical separation of mask substrate fabrication from pattern generation by different manufacturers very problematical and ends with the necessity to introduce x‐ray lithography in relatively large production capacity units consisting of a larger number of x‐ray steppers. The latter is caused by the fact that a storage ring—even in the smallest version, e.g., COSY (Kompakt Speicherring für Synchrotronstrahlung)—has to supply up to 10 x‐ray steppers with light in order to clearly beat the optical techniques with respect to throughput and lower cost level. To prove such statements in pilot production lines, the necessary tools and components for x‐ray lithography are already or will be available for the first time on a commercial basis in the very near future. Especially steppers, sources, and resists with satisfying specifications have been announced by a growing number of vendors. The most critical problem at present is the mask technology and the tools for defect elimination. However, with the existing technologies, the requirements for 0.5‐μm‐design rules will be met very soon on a pilot scale.

ISSN:1071-1023    

DOI:10.1116/1.584026

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

Advances in nanolithography using electron‐beam techniques have allowed a great variety of quantum devices to be fabricated and tested. The critical dimensions governing the design of these devices will be discussed. Fabrication and experimental results of several such devices for studies will be reported. These include structures aiming at the observation of the electrostatic Aharonov–Bohm effect and nonlocal oscillations, superconducting weak links, and devices for the investigation of quantum scattering effects.

ISSN:1071-1023    

DOI:10.1116/1.584027

出版商:American Vacuum Society    

年代:1988

数据来源: AIP

摘要:

Conducting wires of widths down to 0.1 μm have been fabricated in modulation‐doped GaAs/AlGaAs material using SiCl4reactive ion etching with a negative resist mask. The resist used was high‐resolution negative (HNR) and its applicability to microstructure fabrication is discussed. A novel dry etch for GaAs, CH4/H2reactive ion etching, produces low damage and shows much promise for wire fabrication.

ISSN:1071-1023    

DOI:10.1116/1.584028

出版商:American Vacuum Society    

年代:1988

数据来源: AIP