Showing papers on "Anodic bonding published in 1980"

Method and apparatus for thermo-compression diffusion bonding

Abstract: A method which utilizes thermo-compression diffusion bonding to attach a metal foil to structured copper. The different rate of expansion of metal press members with temperature creates a force which squeezes the foil and copper together to achieve a bond when the press and the parts to be joined are heated to an elevated temperature. Because of the high pressure achieved by the press, diffusion bonding occurs at a low enough temperature to avoid problems associated with use of the liquid phase of any of the metals undergoing bonding.

Hermetic glass sealing by electrostatic bonding

Abstract: Electrostatic bonding is a field assisted sealing technique with general applicability to joining glass to conductors, semiconductors and insulators. The process requires high temperature to produce ionic conductivity within the glass. Once the glass is conductive, the application of a high voltage (negative to the glass) across the sample produces a depletion layer at the interface between the pieces being joined. Mobile positive alkali ions move away from the interface, leaving oxygen ions to bond chemically to the other member of the pair. Process requirements are temperature between 400 and 600°C and voltage between 500 and 1500 volts. Bonding current varies widely with glasses, temperature and time, but typical values are on the order of 1 mA/cm 2 . The properties of the bond formed by this technique are that it will form a hermetic seal between the pieces being joined and that the bond strength exceeds that of the two materials being sealed.

Parameters in solid-state bonding of metals to oxide materials and the adherence of bonds

Abstract: Temperature, pressure and time are parameters in the solid-state bonding of metals to oxide materials. The role of these parameters in the bonding of metals with low melting point to glass and ceramic and their interrelationship is experimentally investigated in relation to the adherence of the bonds. The influence of the surface structure and the unevenness of the bonding surfaces is also considered.

Metal-composite bonding

Abstract: A method of bonding a graphite fiber reinforced glass matrix composite to a metal structure comprising depositing a layer of eutectic alloy metal component to the bond surfaces of the metal and composite followed by placing the thus treated bond surfaces of the metal and composite together with a layer of eutectic alloy containing such metal therebetween. The metal-bond-composite is then heated to melt the alloy and bond the composite to the metal. Articles formed by such a process are also described. The method has particular utility in bonding cooling channel containing metal bases to graphite-glass composite laser mirrors.

Electrostatic bonding using externally applied pressure

Abstract: A method and apparatus for electrostatic bonding of a layered structure having at least one glass stratum by heating the layered structure to a temperature above the annealing point of the glass stratum, by applying a predetermined pressure and voltage potential across the layered structure while the layered structure is maintained at an elevated temperature. Application of pressure across the heated layered structure permits electrostatic bonding of non-complemental surfaces to form a laminated structure.

Surface texturing of fluoropolymers

Abstract: This invention is concerned with providing improved surface texturing for adhesive bonding, metal bonding, substrate plating, decal substrate preparation, and biomedical implant applications. The invention is particularly concerned with epoxy bonding to polymers that typically exhibit low adhesion and bonding metals to a desired thickness to a polymer substrate. The surface 12 to be bonded is first dusted in a controlled fashion to produce a disbursed layer of fine mesh particles 14 which serve as masks. The surface texture is produced by impinging gas ions on the masked surface. The textured surface takes the form of pillars or cones. The bonding material, such as a liquid epoxy, flows between the pillars which results in a bond having increased strength. For bonding metals a thin film of metal is vapor or sputter deposited onto the textured surface. Electroplating or electroless plating is then used to increase the metal thickness to the desired amount.

Magnetic transducer head and method of manufacturing the same

Abstract: A magnetic transducer head employing magnetic alloys as a core material and a method of manufacturing the same are disclosed A pair of core blocks made of magnetic alloys are bonded together by a glass to form an effective gap therebetween A thin metal layer is formed on the surface of the core blocks which results in a transition layer of the metal accompanied with oxide of the metal between the core block and the glass upon heat treatment for glass bonding to strengthen the bonding

Method for diffusion bonding workpieces and article fabricated by same

Abstract: A diffusion bonding method for assembling members formed from a liquid phase system material into a monolythic structure free of flaws and distortion. Member blanks are first formed from the material as by compacting or the like and then sintered to have their full density and hardness characteristics. Following sintering, any special surface or internal features are machined into the blanks to define the members. The members are also provided with bonding surfaces adapted to be placed in mating engagement with each other. The members are placed in an assembled relationship with the bonding surfaces engaging each other to define a bonding zone. In some cases, it may also be desirable to place a weight on the assembled members to continuously urge the bonding surfaces toward engagement. In the actual bonding step, the members are heated in a vacuum environment to a temperature intermediate the melting temperatures of the material low and high melting phase components. During such heating, the liquid phase system material of the two members coalesce across the boundary zone to effect an integral joint or bond.

Method of constructing layered glass display panels

Abstract: Method is disclosed for applying sealing glass to glass surfaces intermediate multiple layers, etching channels through the sealing glass and partially into a glass layer, and bonding to the glass layers together to form a unitary glass display panel

Thermo-compression bonding a semiconductor to strain buffer

Abstract: A diffusion bonding press (10) and method are provided for thermocompression diffusion bonding structured copper strain buffers (55, 65) directly to one or each of the two major opposed surfaces (70a, 70b) of a substrateless semiconductor device wafer (70) having a first metal coating (94, 96) of titanium, chromium or nickel and a layer (98, 100) of copper, silver or gold. The expensive tungsten or molybdenum support plate conventionally employed to provide structural integrity to the relatively fragile semiconductor device wafer is thus eliminated. The wafer may have a passivated beveled outer edge surface (70c) prior to bonding. A selected portion of each structured copper strain buffer is diffusion bonded to the semiconductor device wafer while subjecting the wafer only to substantially compressive force, thus avoiding wafer fracture during the bonding process. The structured copper strain buffers may further have lateral extents no greater than the lateral extent of the respective semiconductor device wafer surface in contact therewith, allowing the beveled surface to be cleaned and passivated after attachment of the strain buffers to the wafer via diffusion bonding. When only one buffer (55 or 65) is bonded to the wafer, a rigid member, such as quartz, may be interposed between the plate of the press and the noncoated surface of the wafer.

Glass/ferrite interactions and corrosion of gap glasses in recording heads

Abstract: Certain glass compositions in common use as gap spacers in ferrite recording head sliders have been shown to interact with air at 75% R.H. The reaction proceeds at 20°C and the corrosion products appear within a few days. The products vary from shape-less lumps to long single-crystal whiskers. In the presence of 300 ppb each of SO 2 and NO 2 the products are more voluminous. While the products are more prominent at the interface between glass and ferrite, they also appear on polished bulk glass specimens in total absence of a ferrite. The effect has been traced to the diffusion of lead, barium or lanthanum to the glass-air surface where the ions react with the atmosphere. An interaction between glass and ferrite was observed to occur during glass bonding. This interaction was indicated by the appearance of prominant grain boundaries in the ferrite at the ferrite/glass interface. Transgranular grain etching was also found. It is believed that interdiffusion of glass and ferrite components occurs and that this contributes to the mobility of the metal ions in the glass.