Showing papers on "Anodic bonding published in 1978"

Enhancing Ultrasonic Bond Development

Abstract: To enhance ultrasonic bond development, an improved understanding is needed of the processes taking place at the bond interface. This work is designed to determine the role that bonding parameters play in contributing to bond development. Of particular concern are the effects created by the machine variables, i.e., load, power, and time. Silicon was selected as a bond surface for aluminum wire bonds. The brittle nature of silicon provides a permanent record of the bonding history. With both the crystal orientation and defects of the silicon well characterized prior to bonding, features such as the location of residual bonding strains in the silicon were determined. The pattern of partially bonded material exposed by peeling underdeveloped bonds simulates a torus (or doughnut) with an unbonded central region. Features of aluminum wire bonds to aluminum, glass, beryllium, and silicon were compared to show that a common mechanism exists independent of the bond surface material. The ability to bond to silicon varies with wire composition. For example, both Al-0.5% Mg and pure Al wires bond readily, while Al-l% Si wire does not. Two modes of material flow characterize interfacial behavior. Ultrasonic energy promotes a material softening which, in conjunction with the applied load, results in a gross flow to expose fresh material for bonding. In the second stage of material flow, a wave form is propagated through the wire to the periphery of the wire-silicon interface. This wave form is observed as a periodic cutting action into the silicon perpendicular to the pulsing direction. A fine ball-like formation in the grooves of the wave region at the bond zone was a feature common to the different bonding surfaces. The wavelength and wave amplitude vary linearly with the applied power as does the tip-to-tip displacement of the wedge. The groove spacings are of the same magnitude as the wedge displacement. For constant power and time, increased load increases the size of the central bond region that does not experience the wave action. For constant load and power, the width of the wave affected periphery increases toward the center of the bond with time. The method of thermally induced stacking faults by steam oxidation was used to characterize the residual bond strains in the silicon. Faulting was found in the peripheral region of the bond where the wave action was operable. This faulting correlated to stresses generated in the pulsing direction and not to the directions of gross material flow. Reliable bonding depends upon a proper control of the gross and wave flow processes by optimizing material properties as well as machine variables. A model has been developed to qualitatively relate the influence of these variables and the manner in which a change in one parameter affects the response of the remaining variables.

Analysis of the oxide/semiconductor interface using Auger and ESCA as applied to InP and GaAs

Abstract: This paper compares the Auger and ESCA techniques used to characterize the interfaces of thermally grown and anodic oxides of InP and GaAs. In the anodic oxide of GaAs, the Ga–O bonding extends deeper into the GaAs than the As–O bonding. In the anodic oxide of InP, both the P–O and In–O bonding penetrate to the same depth. The anodic oxide–GaAs interface changes with electrolyte. There is elemental P at the interface of the thermal oxide on InP, but it was not possible to prove or disprove the existence of elemental As at the anodic oxide/GaAs interface. It was found that the ESCA technique provided much needed bonding information which greatly facilitates characterizing the interface. It appears essential that both composition and bonding be determined.

Bioglass coated metal substrate

Abstract: A prosthesis for cement-free bonding to bone comprising a metal substrate coated with a biologically active glass or glass-ceramic of uniform composition and thermal coefficient of expansion and free of flaws resulting from thermo-mechanical stresses, the glass coating being bonded to the metal substrate by ion diffusion of the interface wherein the thermal coefficients of expansion of the metal substrate and the glass or glass-ceramic coating are substantially different.

Method of bonding microelectronic chips

Abstract: Disclosed is a method of bonding microelectronic chips to bonding surfaces utilizing thin, soft bonding material preforms. The bonding material, such as indium, is formed on a carrier strip. A portion of the material is transferred from the strip by bringing it in contact with the bonding surface and supplying pressure to the strip. The chip may then be bonded to the coated surface.

Method for low temperature bonding of silicon and silicon on sapphire and spinel to nickel and nickel steel and apparatus using such _a bonding technique

Abstract: A method for low temperature bonding of silicon and silicon on sapphire and spinel to nickel and nickel steel using a layered structure with an aluminum interface between the nickel or nickel steel and the silicon. The bonding is achieved in a reducing atmosphere using a temperature of 640 to 650 degrees C. with a pressure of 100 to 150 psi on the layered structure for a period of approximately five minutes with a subsequent cooling to avoid strains in the bond. An example of the transducer apparatus utilizing such a bonding technique includes a nickel steel housing and a silicon on spinel transducer wafer having a silicon peripheral pad with an aluminum layer bonding the silicon pad to the nickel steel housing. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to bonding techniques. More specifically, the present invention is directed to a method for bonding silicon to nickel and a transducer apparatus utilizing such a bonding technique. 2. Description of the Prior Art The development of transducers such as those shown in U.S. Pat. Nos. 3,230,763 and 3,537,319 has led to a composite structure using silicon on sapphire (SOS). The sapphire with a silicon epitaxial layer grown on it may be used for pressure transducers and provides, in effect, strain sensitive resistors. The strain sensitive elements are shaped on the sapphire wafer by a suitable etching process with the resulting wafer being cut into a desired configuration by a diamond saw. A recent development has taken advantage of an improved stress transmission characteristic which is produced by having the composite transducer structure utilize silicon on spinel. Such a structure results in a superior transducer while retaining its electrical insulating characteristics. The production of such silicon on sapphire and silicon on spinel is a well-known technique and is discussed in the Journal of Crystal Growth (1971) in an article by G. W. Cullen on pages 107 to 125 entitled "The preparation and Properties of Chemically Vapor Deposited Silicon on Sapphire and Spinel." In both of these structures the composite end product must be ultimately bonded to a metal support or transducer housing in order to produce a viable transducer. The poor wettability of spinel and sapphire by many metals is well-known and offers a serious problem to the bonding of these materials to metals as well as to ceramics and glasses. One prior art attempt to bond sapphire to metal involved the growing of multiple metallic layers on one or both of the elements and then fusing them together at relatively high temperatures. However, the high temperatures involved can damage the strain elements deposited on the sapphire. On the other hand, the bonding of silicon on spinel to metal remains a problem which has limited the use of the corresponding composite transducer in a useful product. SUMMARY OF THE INVENTION An object of the present invention is to produce a method for bonding silicon to nickel. Another of the present invention is to produce an improved transducer apparatus utilizing a novel method of bonding of silicon to nickel. In accomplishing these and other objects, there has been provided, in accordance with the present invention, a low temperature bonding method for bonding silicon to nickel by introducing therebetween a layer of aluminum and subjecting the layered structure to a pressure of 100 to 150 psi at a temperature of 640 to 650 degrees C. for a period of approximately five minutes in a reducing atmosphere. An example of a transducer apparatus utilizing such a bonding technique includes a nickel steel housing and a silicon on spinel transducer wafer having silicon peripheral pads with an aluminum layer bonding the silicon pads to the nickel steel housing.

Method of applying contacts to a silicon wafer and product formed thereby

Abstract: Metal contacts are deposited on a clean surface of a silicon wafer by coating the wafer with a glass during diffusion to form a junction inwardly of the surface, applying a photoresist layer to the glass, phtographing and developing a pattern for the contacts on the photoresist layer, etching out underlying portions of the glass layer, depositing the metal contacts in the voids so created, and then removing the entirety of the photoresist and glass layers.

Process for bonding an improved metallic support member to glass surfaces

Abstract: The invention disclosed provides a new improved metallic support member and process for bonding the metallic support member to a glass surface by means of an intermediate vitreous coating.

Radiation sources and process

Abstract: The invention relates to radiation sources comprising a substrate having an electrically-conductive non-radioactive metal surface, a layer of a metal radioactive isotope of the Scandium group, which in addition to scandium, yttrium, lanthanum and actinium, includes all the lanthanide and actinide series of elements, with the actinide series usually being preferred because of the nature of the radioactive isotopes therein, particularly americium-241, curium-244, plutonium-238, californium-252 and promethium-147, and a non-radioactive bonding metal codeposited on the surface by electroplating the isotope and bonding metal from an electrolytic solution, the isotope being present in the layer in minor amount as compared to the bonding metal, and with or without a non-radioactive protective metal coating covering the isotype and bonding metal on the surface, the coating being sufficiently thin to permit radiation to pass through the coating. The invention also relates to a process for providing radiation sources comprising codepositing a layer of the metal radioactive isotope with a non-radioactive bonding metal from an electrolytic solution in which the isotope is present in minor molar amount as compared to the bonding metal such that the codeposited layer contains a minor molar amount of the isotope compared to the bonding metal by electroplating on an electrically-conductive non-radioactive metal surface of a cathode substrate, and with or without depositing a non-radioactive protective metal coating over the isotope and bonding metal on The surface, the coating being sufficiently thin to permit radiation to pass through the coating.

耐熱合金Inco.713CのTLP Bondingに関する研究

Abstract: Structure and mechanical properties of heat resistant superalloy Inoc. 713C joint bonded by TLP (transient liquid phase) method being a new diffusion bonding process have been investigated fundamen-tally. Bonding was carried out by using insert metal (Ni-15Cr-3.5B) in a vacuum induction furnace, following by subsequent post heat treatment in order to promote homogenization in compositions. The following results were obtained.1. With increasing the bonding temperature and time, the structure at the bonded interface was improved and became similar to that of the base metal. On the other hand, when bonding was achieved in relatively low pressure, grain coarsening occurred near the bonded interface, on the contrary, the bonded interface made in the high pressure seemed to remain' as grain boundary.2. In bonding for about an hour, the constitution of the bonded interface considerably resembled that of the base metal.3. Solidification time of insert metal estimated from diffusion state of boron was approximately agreed with the result of structure observation.4. By selecting the suitable bonding conditions, tensile strength was easily equivalent to the base metal and also fairly good results about the creep strength were obtained though scattering somewhat.

Strain measuring unit

Abstract: PURPOSE: To increase the dielectric strength between the gauge and the strain body, by bonding the glass with the gauge by anodic bonding and performing bonding with use of eutectic alloy caused between the gauge and the strain body, in bonding the semiconductor strain gauge with the metal strain body. CONSTITUTION: The resistor body 22 is formed in the semiconductor strain gauge chip 21 with diffusion or ion injection, and it is covered with the oxide film 22. Further, opening is made at a given region of the film 23, and the electrodes 24 and 25 to flow current to the resistor body from external are attached, and the metal fine wires 26 and 27 connected to the external electrodes are formed. At the rear side of the chip 21 with this constitution, the glass 28 with anodic bonding having very closer coefficient as the line expansion coefficient of the chip 21 is coated, and this is bonded to the metal strain body 20 via the eutectic alloy layer 29 such as Au-Si and Au-Sn bonded with it. Thus, even with the unevenness due to processing on the surface of the strain body 20, total contact is made possible and no dielectric strength is lowered. COPYRIGHT: (C)1979,JPO&Japio

Method of making flexible carrier tape for semiconductor integrated circuit

Abstract: PURPOSE: To accurately perforate sproket holes, by tentatively coating a prescribed bonding agent as a film on a flexible insulating film and removing unnecessary parts of the coated bonding agent. CONSTITUTION: A bonding agent 2 containing at least 3% by weight of inorganic powder is shaped as a film and tentatively coated on a flexible insulating film 1. Unnecessary parts of the bonding agent layer 2 are thereafter removed. It is easy to exfoliate the unnecessary part the prescribed bonding agent 2 from the film 1. The main constituent of the bonding agent is a polymerized nylon-denatured epoxy resin, a phenolbutyralic bonding agent or the like. Silica, alumina or the like is used as an in-organic material for the bonding agent. Since the bonding agent is coated, sprocket holes can be accurately perforated. Because the bonding agent has a good flatness and is not fluidized when heated, automatic smooth conveyance can be performed. COPYRIGHT: (C)1980,JPO&Japio

Method of fusion bonding non-elastomeric thermoplastic elements with a block structure elastomeric bonding element interposed at the bonding interface

Abstract: OF THE DISCLOSURE A solid block elastomeric bonding element is interposed between the surfaces of non-elastomeric thermoplastic elements to be joined by a fusion bond. The heat necessary for fusion bonding is obtained for optimum results by the incorporation of heat generating particles in the elastomeric bonding element. The particles are indirectly heatable by a high frequency alternating magnetic field or other suitable field for heating the fusion bonding element to a fusion tempera-ture suitable for producing bonding of the non-elastomeric elements. A copolyester block elastomer bonding element is particularly useful for bonding polycarbonate, polyvinyl chloride or polyvinylidene chloride elements to each other, and a copolymer block elastomer is particularly useful for bonding polypropylene and high density polyethylene elements to each other.