摘要:

A focused ion beam of gallium was used to implant films of baked photoresist, spin‐on glass (SOG) and the bilayer combination of spin‐on glass on baked photoresist. Plasma etch conditions were found which gave substantial differences between the implanted and nonimplanted SOG so that the SOG acted as a negative resist. The implanted SOG in the SOG‐photoresist bilayer was patterned and then used as an etch mask during O2reactive ion etching of the photoresist. In this manner, rectangular profile structures of height 2.0 μm and width 0.4 μm were formed where the line width variation along the patterned line is a small fraction of the line width. This bilayer system is shown to be suitable for use in optical trilayer patterning. A new processing sequence for microstructure fabrication is proposed (called dual processing) whereby the bilayer structure is used sequentially in both focused ion beam implantation and trilayer processing (electron beam or optical) to achieve fine features of less than 0.5 μm size within prescribed regions that can be micrometer size.

ISSN:1071-1023    

DOI:10.1116/1.583074

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

This paper reports a reactive ion etching (RIE) technique using a Cl2–Ar gas mixture for anisotropic microprocessing of GaAs and AlGaAs materials and its fundamental characteristics aimed to applications to monolithic integration of optical devices. This technique allows one to realize very fine as well as deep processing perpendicular to the wafer surface with smooth side walls, independent of the crystallographic orientation of these semiconductor materials. The etching rate was found to be controllable over a wide range by suitably adjusting the gas composition and the total gas pressure in this gas mixture. We experimentally obtained the optimum condition for smooth and perpendicular etching for both the materials at the total gas pressure of 2 Pa (1.5×10−2Torr) with the gas flow ratio of Cl2 : Ar=1 : 5. Under this condition the etching rate ratio of GaAs to SiO2was demonstrated more than 70. The surface damage introduced by this RIE was confirmed to be comparable at least to the case of the wet chemical etching through the measurement of photoluminescence intensities from GaAs samples.

ISSN:1071-1023    

DOI:10.1116/1.583076

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

Although dedication of plasma etching equipment strictly to a single process is becoming a common practice in IC labs, a large number of older plasma systems (especially the barrel type) were designed and are still used for multiple processes such as thin film etching in CF4based plasma and photoresist striping in pure oxygen plasma. An investigation of a cross contamination effect is reported here. Silicon wafers coated with aluminum and exposed to a simulated oxygen plasma resist strip process were analyzed using Auger electron spectroscopy and x‐ray photoelectron spectroscopy. Relatively large amounts of carbon and fluorine were found to be present on the wafer surfaces. Wafers exposed to wet chemical treatments were analyzed for comparison. The C and F contamination is believed to be due to redeposition of a fluorocarbon compound on the wafer surface originating from the chamber walls, etc. ESCA examination of the samples resulted in similar observations but the chemical identification of the contamination could not be made.

ISSN:1071-1023    

DOI:10.1116/1.583077

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

Gas phase and surface phenomena responsible for etching polyimide in O2–CF4rf plasmas have been investigated. The dependence of the etch rate of polyimide on the relative concentrations of these two gases was compared with data from optical emission spectra, mass spectra, and x‐ray photoelectron spectroscopy (XPS). The increase in O atom number density in the plasma with addition of CF4to O2certainly increases etch rates over those achieved in pure oxygen plasmas. However, etch rates do not track identically with atomic oxygen emission intensities. Etch rates are enhanced through the reaction of fluorine in the polyimide surface layer while fluorine present in excess inhibits etching through competition with oxygen atoms, resulting in the formation of CF2type bonding at the surface. Removal of the resulting passivation is most efficiently accomplished by exposure of the polyimide to a plasma with higher oxygen concentration, probably due to the presence of ions. The position of the maximum in etch rate distribution with respect to CF4concentration depends on an optimum ratio of O to F atoms in the plasma.

ISSN:1071-1023    

DOI:10.1116/1.583078

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

This paper presents the development of a new trench fabrication technique for silicon substrate utilizing undercutting and selective etching. The technique comprises (1) first aluminum film deposition and its etching with controlled undercut, (2) second aluminum film deposition, (3) second film liftoff, and (4) silicon substrate selective and anisotropic etching using the first and second films as etching masks. There are two predominant features of this technique. First, trench width is controlled by the first film undercutting. Second, highly selective and anisotropic etching of the silicon substrate is obtained employing the aluminum films as etching masks in configuration with planar plasma etching using CCl2F2gas. Under optimum conditions, trenches of approximately 0.12 μm in width and 0.6 μm in depth are successfully fabricated.

ISSN:1071-1023    

DOI:10.1116/1.583079

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

This paper evaluates personnel exposure to hazardous chemical compounds during the operation and maintenance of a plasma aluminum etcher. Since chemical exposure occurs mainly through inhalation and skin contact, breathing zone samples and chemical residues from the reactor and cold trap were analyzed. Data were collected during normal operation, cleaning. and routine maintenance. The results indicate that the concentration of volatile compounds in the worker breathing zone were at least an order of magnitude lower than recommended limits. Carbon tetrachloride was detected while recharging a reservoir. The concentration of 0.88 ppm was below the maximum recommended 8 h average concentration of 5 ppm. The chemical residue from the cold trap contained a suspected carcinogen: 1,1,2‐trichloro‐1,3‐butadiene (2.0% of sample). Hexachlorobutadiene, which is structurally similar to 1,1,2‐trichloro‐1,3‐butadiene, is a strongly suspected carcinogen with a threshold limit value of 0.02 ppm.

ISSN:1071-1023    

DOI:10.1116/1.583080

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

Two effects are observed in the etching of films of PMMA or polycarbonate by laser radiation of 193 or 249 nm wavelength, when the aspect ratio of the etched hole exceeds unity. The first is an optical effect which results in the edges of the etched area being ablated more slowly than the center. The second effect causes the etch depth per pulse to decrease with increasing depth. This effect is attributed to the partial absorption of the later part of the laser beam by material ablated from the surface.

ISSN:1071-1023    

DOI:10.1116/1.583081

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

A new method for obtaining transmission electron microscope (TEM) cross sections is presented which combines electron beam lithography, optical lithography, and reactive ion etching. The technique uses an electron beam to position and define a line pattern in a desired area. With the aid of a highly selective mask the pattern is transferred into the substrate with reactive ion etching. Uniform features 0.1 μm thick, 0.4 μm high, and 10 μm long have been fabricated for cross sectional viewing in TEM.

ISSN:1071-1023    

DOI:10.1116/1.583082

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

ISSN:1071-1023    

DOI:10.1116/1.583083

出版商:American Vacuum Society    

年代:1985

数据来源: AIP

摘要:

A simple technique for eliminating hillocks in integrated circuit metallization is reported. In this technique, the aluminium film, after deposition on an oxidized silicon wafer and sintering, is stripped off in orthophosphoric acid. The wafer is thoroughly cleaned in DI water and no HF is used. This treatment forms an A12O3+Si dipole layer on the oxide surface and makes it aluminiumphilic. Further aluminization and sintering generate the adherant composite layers of Al,Al2O3+Si on oxide surface and thereby eliminate hillocks.

ISSN:1071-1023    

DOI:10.1116/1.583084

出版商:American Vacuum Society    

年代:1985

数据来源: AIP