Showing papers on "Isotropic etching published in 1973"

Selective Area Metallization by Electron-Beam Controlled Direct Metallic Deposition

Abstract: Direct metallic deposition exploits the advantages of electron-beam exposure for the production of fine structures and avoids the use of resists and chemical etching. The process involves the electron-induced decomposition of metallic compounds in areas precisely defined by an electron probe. In principle, the resistivity of the deposits formed by direct metallic deposition can be controlled by regulating the amount of molecular dissociation which takes place. To date, in experiments with silver chloride, deposits with submicron dimensions have been obtained. Typical sheet-resistance values of the deposits range from 10 to 1000 Ω/square for exposures varied from 3×10−2 to 5×10−3 C/cm2. A Monte Carlo simulation of electron scattering in thin films on a supporting substrate has shown that the minimum deposit dimensions which can be expected from the process vary directly with film thickness and inversely with accelerating voltage. Experimental evidence is in agreement with the theoretical predictions.

A new etching technique for damage track detectors

Abstract: The etching reagents rapidly diffuse in the fine channels produced in insulators by the passage of the charged particles. Conductive channels are thus produced, which penetrate the insulating foils. By applying H.V. square or sirusoidal waveforms through the irradiated insulator, the currents and treeing phenomena produced in the conductive paths increase the preferential chemical etching of the tracks. This type of etching enables us to enlarge the damage tracks at will and in some cases to increase the sensitivity of damage track registration. Furthermore the damage trails produced by heavy ions provide a successful tool to study treeing mechanisms on electrical insulators.

Differential etching of ion-implanted garnet

Abstract: A new technique for generating precise surface structures in single‐crystal garnet materials is described. The crystals are ion implanted in localized areas using photoresist as an implantation mask. The photoresist is removed and the crystals are etched in phosphoric acid. The damaged volumes produced by the ion implantation etch at a substantially greater rate than the undamaged material, thereby producing surface structures. Groove depth can be precisely defined and reproduced by controlling the implantation parameters: ion species, energy, and dose. Undercutting is minimal and etching conditions are not stringent. The method is superior to both standard chemical etching and ion milling. The process has been characterized for H, He, and Ne implantations. It is shown that the temperature dependence of the etching rates for damaged and undamaged material is the same. The increase in etching rate is proportional to the damage concentration. The etching rate profiles are therefore synonymous with the damage profiles produced by the implantation. Etching rates more than three orders of magnitude greater than that of undamaged material have been observed. The etching rates for the three elements used correlate fairly well with the theoretical nuclear stopping power, and the groove depths obtained correlate with the theoretical ion ranges. This method has been used to produce serrated edge grooves which serve as rails for magnetic bubble propagation in conductor‐groove bubble propagation circuits.

Chemical etching of {1 1 1} and {1 0 0} surfaces of InP

Abstract: The effects of a number of chemical etches on the III–V semiconductor InP were studied, using {1 0 0} and {1 1 1}-type faces. The (1 1 1) and (¯1¯1¯1) faces were found to behave differently, and this was attributed to the polarity of the zinc-blende lattice. Curves showing etching rate as a function of penetration were plotted, and it is noted that they demonstrate an enhanced etching rate close to the surface. This is attributed to the damaged surface layer associated with the cutting of a crystal slice. Photographs were taken at various stages of the etching using both the optical and scanning electron microscopes. Both etch pits and etch hillocks were observed. The shapes of the pits are compared to those described in previously published work, and possible reasons for these shapes are discussed. The conditions necessary for the production of an etch hillock are described and it is shown that the measured etching rates are consistent with hillock formation in the case of the 1 HCl∶1HNO3 etch. The mechanisms of dissolution are discussed and it is suggested that both activation control of the dissolution process and diffusion control were observed in the work.

Two‐dimensional distributed‐feedback lasers and their applications

Abstract: We report the operation of two‐dimensional distributed‐feedback (DFB) lasers in which periodic thickness variations exist in two orthogonal directions in the plane of the film By using photoresist and chemical etching, two‐dimensional gratings with periods of 0635 and 434 μm are formed on fused silica substrates For the gain medium, a polyurethane film doped with rhodamine 6G is used Emission characteristics and potential applications of two‐dimensional DFB lasers are discussed

Process for preparing semiconductor

Abstract: A semiconductor is prepared by continuously etching at least two types of silicon compound membranes such as silicon dioxide (SiO2), silicon nitride (Si3N4) or a polycrystalline silicon membrane which are formed on a silicon substrate. A freon gas plasma is used for etching so that the two types of silicon compound membranes are continuously etched in a sloped form without any undercutting, as occurs in conventional chemical solution etching.

Elimination of undercut in an anodically active metal during chemical etching

Abstract: The preparation of a discrete and well-defined pattern of metal or alloy of uniform thickness and composition of magnetic properties by plating the alloy or metal onto a conductive surface which contains narrow photoresist frames outlining the outer edges of the pattern.

Grain Surface Etching Features of Some Heavy Minerals

Abstract: Study of heavy minerals from Upper Cretaceous-Paleocene sandstones of Alberta reveals that imbricate wedge markings, previously successfully reproduced artificially on garnet, are a common feature of naturally etched garnet, sphene and staurolite. Hacksaw terminations are exhibited by naturally etched sphene, staurolite, hornblende, epidote and clinozoisite. Detailed examination of these etch features with the scanning electron microscope has yielded the following information on hornblende and garnet: Etching and eventual removal of hornblende grains by intrastratal solution begins with the smoothing of the cleavage surfaces and simultaneous etching of the grain terminations. Differential removal of cleavage plates at the terminations results in the hacksawed appearance. Cleavage plates retreating away from the terminations are eventually removed exposing deeper cleavage plates; if the etching process continues the grain will evntually disappear. Garnet etching and removal proceeds by solution sculpture of imbricate wedge markings. With further etching the grain is reduced to a skeletal form. Calcite replacement appears to be an important factor in the removal of many heavy minerals, especially garnet. Fragile, hacksawed hornblende grains of this study are interpreted to be the result of intrastratal solution. Although it is possible that a large volume of heavy mineral grains in a sandstone may be completely dissolved by chemical etching, it is doubtful that intrastratal solutions have compositions which are regionally consistent and pervasive enough to uniformly dissolve an entire heavy mineral population.

Silicon dioxide etch rate control by controlled additions of p' 2'o' 5 'and b' 2'o' 3'hooker; colin edwin lambert<tomes; derek william

Abstract: A method of making an integrated circuit in which controlled chemical etching of silicon dioxide layers is achieved by the controlled addition of both phosphorus pentoxide and boron trioxide to the silicon dioxide layers. For a faster rate of etch, the percentage of phosphorus pentoxide is increased and for a slower rate of etch the percentage of boron trioxide is increased.

Method of etching a pattern in a silicon nitride layer

Abstract: Etching of a pattern in a silicon nitride layer provided on a substrate, in which the etching bath consists of a dilute aqueous solution of hydrofluoric acid and phosphoric acid, in which ammonium fluoride is dissolved in a high concentration. Application in the manufacture of semiconductor devices.

Chemical etchant for palladium

Abstract: A process is described for the fabrication of devices in which thin films of palladium are etched by a chemical procedure. This chemical procedure involves first oxidation of the palladium metal to palladium ions and then complexing of the palladium ion and dissolution in the etching solution. Dichromate ion is used as the oxidizing agent and chloride ion as the complexing agent. This chemical etching solution yields patterns of high resolution with high reliability.

Method for fabricating minute openings in insulating layers during the formation of integrated circuits

Abstract: A method in the fabrication of integrated circuits for forming small openings through electrically insulative passivating layers on semiconductor surfaces. First and second layers of different insulative material are formed on the semiconductor surface. Then, a first slot extending through the second or top layer is formed by chemical etching through an etch-resistant mask with an etchant which selectively etches the material in the top layer. The top layer is then covered with a photoresist mask having a second slot which crosses the first slot, and the structure is subjected to chemical etching through the photoresist mask with an etchant that selectively etches the material in the first or bottom layer to, thereby, form a small opening through this bottom layer which is defined by the intersecting portions of the first and second slots.

Method for manufacturing thin plate glass

Abstract: A method of manufacturing a thin plate glass by chemical etching, wherein a chemical etching solution is sprayed from a sprayer onto the surface of a thick plate glass held substantially in a vertical position, and said thick plate glass and said sprayer are caused to make a relative movement during the operation of spray, whereby the etching solution is sprayed substantially uniformly to the surface of the thick plate glass.

Method for producing a synthetic resin substrate

Abstract: A synthetic resin substrate having a roughened surface suitable for obtaining a high adhesion with film deposited thereon can be obtained by lamintating an aluminum foil which has been subjected to electrolytic etching and a synthetic resin substrate so that the etched surface of the aluminum foil contacts the resin substrate, combining them under heat and pressure and then removing the aluminum foil by chemical etching.

Silicon nitride on silicon oxide coatings for semiconductor devices

Abstract: A method of manufacturing a semiconductor device wherein a silicon nitride film covers the exposed surfaces of an oxide film and the exposed major surface of a semiconductor body, and wherein holes are formed by chemical etching only in the portion of said silicon nitride film directly contacting said major surface, thereby obtaining precise etching of the insulating covering.

Method of manufacturing etched structures in substrates by ion etching

Abstract: Etching masks for ion etching which consist of a material which has an etching velocity which is independent of the angle of incidence of the etching ion beam are of advantage in particular when etching deep structures ( > 1 Mu m) in a substrate of a material having an etching velocity which depends on the angle of incidence of the ion beam. Material of the etching mask: titanium.

Method of manufacturing semiconductor device with nitride oxide double layer film

Abstract: A method of manufacturing a semiconductor device wherein a silicon nitride film covers the exposed surfaces of an oxide film and the exposed major surface of a semiconductor body, and wherein holes are formed by chemical etching only in the portion of said silicon nitride film directly contacting said major surface, thereby obtaining precise etching of the insulating covering.

Method of manufacturing semiconductor devices

Abstract: A method of manufacturing semiconductor devices comprises the steps of covering the surface of a semiconductor substrate with an insulating film, leaving a designated surface portion uncovered and exposed A silica glass film containing an impurity is formed on top of the insulating film and on the said surface portion Thereafter, the substrate is heated to diffuse the impurity from the glass film into the semiconductor substrate, forming a transmuted layer whose saturated concentration is lower than the concentration of the impurity contained in the glass film and which transmuted layer has an etching rate lower than that of the glass film After the etching step the glass film is removed from the transmuted layer and from said surface portion by chemical etching

Method of etching a semiconductor element

Abstract: Gas etching method in which an etching gas generated through reaction of HC1 and HNO3 is applied onto a semiconductor substrate while maintaining the temperature of the substrate at a relatively low temperature above the boiling point of water. This etching method is particularly effective for the compound semiconductor such as GaP, GaAs, GaAsP and the like.

A Spectroscopic Monitor for Sputter-Etching Processes

Abstract: Sputter-etching is a convenient technique for metal pattern generation on complex integrated circuits. It is particularly advantageous for multimetal systems because it completely eliminates the possibility of undercutting of the lower metal layers as can occur with chemical etching. A real-time monitoring system has been developed for monitoring the sputter-etching process when it is used for metal pattern generation with a beam lead metallization system consisting of titanium, platinum (or palladium), and gold. The intensity of the uv atomic radiation emitted by sputter-etched atoms which are excited in the sputtering discharge is monitored. The system has been used with both triode and diode types of sputter-etching systems and can reliably be used to tell when a given metal layer has been completely removed. A detailed description of the monitoring system and its performance is given.

Chemical fabrication of overhanging ledges and reflection gratings for surface wave devices

Abstract: A method is described of etching structures into α quartz and LiNbO 3 , two materials widely used in surface wave devices and which heretofore have not been found suitable for use with chemical etching techniques, in which concentrated HF acid at a predetermined temperature is used as an etchant, and the formation of overhanging ledges accomplished through a specific crystal orientation. Steps are shown which avoid the problems associated with suitable masking of the surface, which problems were encountered in the prior art, a primary step being one of a mechanical-chemical polishing to assure that the resist mask adheres to the surface properly.

Surface-roughening by electron-beam, plus etching - improves ahesion of molybdenum coatings and light-metal bearing lubrication

Abstract: The roughening of metal surfaces by irradiation with an electron-beam, followed by chemical etching. The electron beam produces a suitable network or honeycomb, and the energy-density and intensity controls the depth of localised melting, structural alteration and/or oxidn. the metal parts are then chemically etched so that the surface is selectively attacked, esp. at the oxidised points. By varying the energy of the electron beam and the type of etchant, any desired surface-roughness can be obtd. with this process it is possible to spray molybdenum onto a layer of hard-chromium or onto copper and its alloys. A metal surface can be roughened to improve lubrication e.g. on a light-metal bearing surface, where the electron-beam simultaneously hardens the surface, thus eliminating chatter-marks.

Mechanism of condensation. I. Direct determination of coefficients for condensation of molecular beams of sodium chloride on oriented single crystals of NaCl

Abstract: Coefficients for condensation of a composite beam of NaCl(g) and Na2Cl2(g) on the 100 face of oriented single crystals of sodium chloride have been measured over a range of crystal temperature from 185–700°K, over a range of 50 in dislocation density at the crystal surface, as a function of molecular beam flux, as a function of deposition time, and as a function of the angle of impingement between the molecular beam and the crystal surface. In one set of experiments a thin layer of silicone oil was spread over the surface of the crystal prior to molecular beam deposition. Crystal surfaces have been studied by chemical etching and microscopic examination. It is concluded that dislocations at the surface of the oriented crystal serve as intrinsic nucleation sites for molecules in a two dimensional, mobile adsorbed surface state. The density of molecules in the mobile surface state depends on the flux of the molecular beam. At sufficiently low crystal surface temperature, centers of nucleation are generated ...

Electrolytic anticompromise apparatus

Abstract: Microelectric devices and circuits, such as are found in semiconductor and hybrid microelectronics, are rendered unrecognizable and are destructed by means of an electrochemical reaction comprising an electrochemical or chemical etching and/or de-plating process.

The cleaning of magnetic ion pumps by chemical etching

Abstract: A chemical etching method is described to improve the speed and ultimate vacuum of sputter ion pumps. The entire pump is immersed in strong acid solution in order to avoid the difficult and unnecessary task of disassembly recommended by the manufacturers.

Dislocation etchant for beryllium oxide

Abstract: A hydrochloric acid chemical etchant for BeO was refined and evaluated. The etchant, when used for 20 min at 120°C on chemically polished surfaces, produces distinctive pits at dislocations intersecting the (0001) and (101) surfaces. Correspondence of etch pits and dislocations was inferred by comparing the enlargement of pits with etching time and the constancy of pit density with continued etching. On {1010} surfaces, the etchant is not sensitive to sites of defect emergence and hence leaves a relatively flat, featureless surface. The etch rates and activation energies are given for {0001}, {1010}, and {101} surfaces. The reaction mechanism is discussed.

The use of gas-discharge etching for the study of the structure of polymer mixtures☆

Abstract: Using polymer mixtures with different chemical properties a study was made of the relations which govern etching of polymer mixtures in the plasma of a high frequency oxygen discharge. It was shown that phases of the dispersed system, on reacting with the plasma of the oxygen discharge, behave independently. It was established that information concerning rates of etching of polymers being available and determining by electron microscopy whether a certain part of the etched surface is projections or hollows, the polymer compositions can be subjected to phase analysis.