Showing papers on "Active surface published in 1994"

Method for reclaiming substrate from semiconductor wafers

Abstract: A method of reclaiming a substrate wafer and a reclaimed substrate wafer. A semiconductor wafer having external layers from previous processing is reclaimed by etching the external layers and cup-wheel grinding an active surface of the wafer to remove semiconductor components such as diffused regions. Either the active surface or the backside of the wafer is then polished to a mirror finish to provide a highly crystalline surface. The cup-wheel grinding produces a pinwheel surface roughness pattern and is accomplished by grinding the wafer with a cup-shaped grinding wheel having an axis of rotation parallel to but offset from an axis of rotation of the wafer. Preferably, the rim of the cup-shaped grinding wheel always passes over the axis of rotation of the wafer.

Flip chip semiconductor device with dual purpose metallized ground conductor

Abstract: Semiconductor device for the microwave frequency ranges includes a semiconductor element of the "flip chip" type which comprises a semiconductor substrate having an active surface with at least one integrated circuit, a plurality of metal input-output pads and a circuit of transmission lines of the coplanar type having conductor strips and ground metallizations disposed on the active surface. A circuit of transmission lines of the microstrip type with conductor strips disposed on a surface opposed to the active surface and whose ground metallizations are formed by the ground metallization of the active surface. A base plate comprising an insulating substrate having a front surface with a plurality of metal input-output pads and ground metallizations patterned so as to be in electrical contact with the ground metallizations of the active surface of the semiconductor element when the latter is bonded to the base plate. The active surface of the semiconductor element is bonded to the front surface of the base plate with the corresponding input-output pads in electrical contact with one another.

Apparatus for producing rubber mixtures

Abstract: An apparatus for producing rubber mixtures, including a ram kneader for the master batch, and disposed therebelow a ram-less kneader that operates in a batch process and to which the master batch is supplied without intermediate storage thereof. To rapidly cool the master batch in the ram-less kneader and to be able to reliably and rapidly carry out the finish mixing process, only a portion of the active surface of the rotor of the ram-less kneader is provided with a surface wear protection layer. This layer is preferably provided only in the region of the active edges of the raised portions of the rotor, while the remaining portion of the active surface is free of such a wear protection layer.

Monitoring of multiple-electrode gas sensors

Abstract: A gas sensor, suitable for use under non-steady state conditions, has a gas-sensitive resistor (18) with pairs (N, W) of electrodes which either have different spacings between the electrodes of a pair, or comprise a pair at the active surface and further pairs buried in the resistor at different distances from the active surface. The sensor can be used in place of a sensor array, and is coupled to means for processing the resistance signals to detect and/or measure at least one target gas. The sensor is self-diagnostic, and factors such as relative humidity and ambient oxygen, that can otherwise affect the readings, can be compensated for without the aid of additional sensors for that purpose. An operating line or surface ((a), (b)) is defined for the expected behaviour of the sensor, and the resistance signals from the electrode pairs are processed so as to give information which is then related to the operating line or surface, so as to reveal, in terms of error indications, any malfunction of the sensor and/or the presence of specific constituents of the gas mixture.

Cored battery plates for lead/acid batteries

Abstract: Methods for fabricating cored structures are provided. The cored structures may particularly find usefulness as cored battery plates for use in lead/acid batteries. A pre-formed core element is provided, and on its surfaces there is placed a thin layer of an active surface material. That active surface material is one which may enter into a chemical or electrochemical process when in use and in the presence of an electrolyte or other agent which will promote such chemical or electrochemical process. In the case of lead/acid batteries, the active surface is lead or lead oxide. The core element is generally one which does not bond with the active surface material, but will if the active surface material is ion bombarded or neutral atom embedded into the surface of the core, and where the amount of bombardment or embedment is determined by controlling the accelerator voltage. A typical cored battery plate for lead/acid batteries will have titanium or other low resistivity metal, with titanium at its outer surface in any event, and with lead having been ion implanted onto the surface of the titanium until such time as an essentially pure lead surface is attained. Further lead may be placed using other methods until sufficient lead is present as to form the active lead surface. The lead may be subsequently oxidized.

Methods of hierarchical control for a segmented active mirror

Abstract: The PAMELA segmented optical surface concept uses the cellular automata paradigm to build up an active surface of individually controlled elements that maintain edge-match by relying on electronically sensed nearest neighbor edge-to-edge errors. The segments are controlled in tilt directly from a wavefront sensor (e.g., of the Hartmann-Schack type) in a separate parallel loop. The approach obviates the matrix operations needed in a typical multiple-input, multiple- out (MIMO) servo control system. In this manner, the segmented optical system is extensible to arbitrary aperture diameter by gradually building up the active surface using identical elements. This paper addresses methods to improve the real-time adaptive control of such a surface using hierarchical control architectures.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Analysis of liquid solutions

Abstract: Low concentrations of target species in liquid solutions are analysed using a simple, disposable, electrode sensor element (1) in the form of a flat strip (10) of insulating substrate material with one or more flat electrodes (12) printed on it. The electrode is overlaid with an insulating layer (14) which as a through aperture (16) exposing an active surface (18) of the working electrode (12). The area of the active surface is precisely known. In use, the electrode is vibrated in a plane normal to the plane of the substrate. In preferred arrangements this vibration is intermittent. The sensor, vibrated at a known frequency, produces a stable and repeatable current signal representing concentration of the solution. Any reagents necessary are incorporated in the disposable sensor element as supplied, in a further coating (20) which dissolves when the sensor element is immersed in the solution. Such a coating can also be used to prevent contamination of the active surface (18) before use. The sensor elements may be made in a form in which the electrode working surfaces are exposed only when the element is broken off a larger body, which may be a continuous tape or strip.

Apparatus and method for transmission of high voltage direct current

Abstract: The invention relates to an electrode (1) for use as one pole when transmitting high voltage direct current in the ground and/or in water. The electrode (1) is arranged to be positioned in one borehole (10), and comprises a current lead-in means (2), and a structure (3) in conductive contact with the current lead-in (2), which structure (3) is provided with an active surface (3) of an electrochemically active coating (4). The structure (3) is preferably a pleated or corrugated structure, for achieving an enlarged active surface. The invention relates also to a process for the transmission of high voltage direct current by using a cable and a pair of electrode arrangements, whereby each arrangement consists of one or several electrodes, and whereby one electrode arrangement functions as anode and the other arrangement as cathode. The electrodes are submerged in their respective borehole, made at end points of a distance over which current is to be transmitted, down to a layer in the earth having good conductive properties, and leading the current in said layer and in the cable.

Chip mounting method, chip mounting structure, and electro-optical device and electronic printing device using it

Abstract: PURPOSE:To prevent the contact and crosstalk of a chip to an active surface by electrically connecting the surface electrode of the chip to a wiring electrode formed on an insulating base through a specified photoresist layer. CONSTITUTION:A photoresist layer 14 containing a conductive particle 13 is patterned only in the position of the connecting pad of a wiring electrode 12 on a base 11, and the surface electrode 16 of a chip 15 is connected to the photoresist layer 14. The base 11 and the chip 15 may be mutually fixed through an adhesive. According to such a constitution, no material is present between the surface electrodes 16 even if the pitch between the surface electrodes 16 is small. In this case, the photoresist containing the conductive particle means a one which can be patterned by photolithography and is obtained by dispersing the conductive particle in an ultraviolet ray hardening type resin which is thermally or optically hardened after patterning, and the kind of ultraviolet ray hardening resins is never particularly limited as long as they have such a property.

Scaling and Active Surface of Fractal Membranes

Abstract: We study the properties of a Laplacian potential around an irregular object of finite surface resistance. This describes the concentration in a problem of diffusion towards an irregular membrane of finite permeability. We show that using a simple fractal generator one can approximately predict the localization of the active zones of a fractal membrane of infinite permeability. When the the permeability of the membrane is finite there exists a crossover length L c : In pores of size smaller than L c the flux is homogeneously distributed. In pores of size larger than L c the same behavior as in the case of infinite permeability is observed, namely the flux concentrates at the entrance of the pore. From this consideration one can predict the active surface localization in the case of finite permeability. We then show that a coarse-graining procedure, which maps the problem of finite permeability into that of infinite permeability, permits to obtain the dependence of the resistance and of the active surface on the surface and bulk properties. Finally, we show that the fractal geometry can be the most efficient for a membrane that has to work under very variable conditions.

Capacitive air-fuel ratio sensor

Abstract: A new mechanism for determining the stoichiometric air-fuel ratio (A.F) of the concentrations of oxidizing and reducing species in a gas phase is presented. The mechanism, which appears suitable for use in the automotive application, is the reversible change in the work function of Pt (by as much as 0.7V). This change occurs at elevated temperatures when the Pt is alternately exposed to dilute mixtures of oxidizing (oxygen) and reducing (hydrocarbons and related molecules ) species that are rich or lean of their stoichiometric ratio. The change can be electrically monitored by the Kelvin vibrating capacitor method or other capacitive techniques. The sensitivity to A/f is verified by comparing the Kelvin signal with that of a ZrO2 electrochemical A/F sensor whose working Pt electrode is simultaneuosly the active surface in the Kelvin measurement. With the observation that O2 pumping to or from the active Pt surface with the ZrO2 cell ran also significantly affect the work function, the possibility exists for developing an extended-range A/F sensor using this mechanism.

Integrated circuit package without carrier

Abstract: PURPOSE: To perform the bonding of an integrated-circuit die to a substrate without the requirement for a carrier. CONSTITUTION: An integrated-circuit die 10 has a facing active surface 20 and inactive surface and side surfaces 26. The material of an electric insulating layer 22 is formed on the inactive side surfaces. A metal mask 24 is formed so as to cover the active surface and the covered side surfaces. The metal mask includes slots 28, 30, 32 and 34 extending onto the side surfaces and the active surface. The arrays of the slots correspond to the arrays of input/output contact pads 12, 14, 16 and 18. The metal is sputtered in the slots. Thereafter, the mask 24 is removed. An L-type conducting trace is provided along the active surface and the side surfaces from the contact pads. An assembly can be provided on the substrate on the inactive surface and the L-type trace bonded to the contact pads 12-18 on the substrate. This assembly allows inspections at a die level.

Monolithtic semiconductor device for generating surface skimming laser

Abstract: PURPOSE: To easily select wavelength output from several different values by providing a set of epitaxial layers, including at least two active region layers adjusted to a wavelength different from a low-clad layer on a common substrate. CONSTITUTION: For a semiconductor main body 10, a thick low waveguide layer or clad layer 12 and thin layers 13-15 for respectively constituting one of the three active regions of a surface-skimming laser are continuously grown on a P-type or a semi-insulation substrate 11 by an MOCVD process, for instance. Then, the active layer 15 which is closest to an active surface 16 is provided with a shortest band gap and is raised by a longest wavelength, the band gaps and raising wavelengths of the remaining two layers 14 and 13 are selected, so as to gradually increase and respectively decrease as a distance from the active surface 16 gradually is increased towards a substrate 11. From this structure, a single-surface skimming laser, a dual-surface skimming laser or a three-beam radiation surface-skimming laser is assembled.

Internal closed magnetic circuit type anisotropic magnet

Abstract: PURPOSE:To contrive to increase a surface magnetic field peak value and the arrival length of lines of magnetic force on the active surface of a magnet by a method wherein the direction of orientation of the axes of easy magnetization of magnetic powder particles in an orientation region is orientated in an orientation, which passes through the interior of the magnet from the peripheral edge part of the region and is again focussed in the central part of the region. CONSTITUTION:The orientation region of one or two magnetic powder particles or more is provided on an active surface consisting of a plane or a curved surface. The direction of orientation of the axes of easy magnetization of the magnetic powder particles in this orientation region is orientated in such a way as to return along a continuous line, which passes through the interior of a magnet from the peripheral edge part of the region and turns again to the center part of the region. As a result, such an aspect as if the axes of easy magnetization are arranged along the pattern of the annual rings on the section rectangular to the active surface is shown in this region. Accordingly, the distribution of lines of magnetic force subsequent to magnetization also coincides with the axes of easy magnetization and a wasteful radiation of the lines of magnetic force to the outside is completely eliminated. Thereby, the surface magnetic field peak value and the arrival length of the lines of magnetic force on the active surface of the magnet can be remarkably improved.

Active Surface of γ-Al2O3-Supported Co3O4.

Abstract: Samples of Co3O4 deposited on two types of γ-Al2O3 with different textures are investigated. A kinetic method employing reduction by hydrogen is used to provide a differential determination of the transition metal oxide surface, and magnetic and XPS measurements are also employed. It is found that, depending on the concentration of the impregnating solution, the value of the surface area of supported Co3O4 passes through a maximum. The concentration at which a maximum surface area of the active phase should be expected has been calculated, and a good correlation has been found with the experimental value. It is established that the differences in the support texture characteristics such as specific surface area, pore volume, and pore size distribution affect the active phase distribution on the support surface, and hence the interaction between the active phase and the support. It is concluded that the amount of the Co3O4 phase formed and its surface area depend not only on the impregnating solution concentration and the preparation temperature but also on the support texture.