Showing papers on "Anodic bonding published in 1983"

Anodic bonding of imperfect surfaces

Abstract: The intimate surface contact necessary for anodic bonding of a metal to a glass is examined in terms of the electrostatic forces which promote this contact and surface imperfections which prevent this contact. Surface imperfections that are considered include foreign particles, isolated hillocks, and periodic curved and angular surfaces. With curved and angular surfaces, a critical voltage exists that causes spontaneous mating of the surfaces by elastic or plastic deformation. Below this voltage, intimate surface contact is achieved by viscous flow. For isolated hillocks and foreign particles, surface conformation generally occurs by viscous flow because of large stress concentrations at these imperfections. The resulting time required for intimate surface contact is a very sensitive function of the imperfection size.

Solid state metal-ceramic bonding of platinum to alumina

Abstract: The formation and resulting mechanical strength of solid state metal-ceramic reaction bonds of alumina to platinum are investigated in terms of the effects of three main parameters — bonding temperature, time at temperature and contact pressure. Also the effect of the subsequent operating temperature on the bond strength is examined. An optimum bonding regime can be devised to create platinum-alumina bonds of optimum strength and durability, suitable for use in practical bonding applications.

Apparatus for thermo bonding surfaces

Abstract: Apparatus and method for bonding surfaces together. A laser beam is applied to the opening in a bonding tip. The bonding tip includes a central cavity forming a black body tapered from the opening to a second tip end. The heated tip end is applied to the fuseable surfaces in either a thermocompression or thermosonic bonding operation.

Semiconductor device with an improved bonding section

Abstract: A semiconductor device with a bonding section comprising a semiconductor substrate (11), a silicon layer (23) formed on the semiconductor substrate with a first insulating layer (20) interposed therebetween, and a bonding pad (25) formed on the silicon layer with a second insulating layer (24) interposed therebetween. The silicon layer is substantially the same size as the bonding pad. When a lead line (26) is bonded to the bonding pad, the silicon layer lessens the stress caused by the bonding.

Method of bonding a poly (vinylidene fluoride) solid to a solid substrate

Abstract: The invention deals with a method of bonding a poly(vinylidene fluoride) solid to a variety of solid substrates, in an application typically using the piezoelectric properties of the material The bonding method entails surface preparation of the poly(vinylidene fluoride) by a variety of steps including activation of the surface by plasma etching to cause the surface to wet the adhesive used in the bonding process The bonding method produces bonds of increased strength and having good electrical properties

Structured Copper: A Pliable High Conductance Material for Bonding to Silicon Power Devices

Abstract: The large difference in thermal expansion between silicon and the high conductivity metals is a major problem to be solved in the packaging of high power silicon devices. One solution is by the use of structured copper which is made of many separate copper wires and can he directly attached to silicon without introducing large stresses. Methods of preparing structured copper are presented along with some examples of its application.

Improved Glass-to-Metal Sealing Through Furnace Atmosphere Composition Control

Abstract: The ability is demonstrated to produce consistently an intergranular oxide layer between 2 µm and 10 µm depth on Kovar alloy using a humidified hydrogen nitrogen furnace atmosphere. Oxidizing the Kovar to a 2-10-µm intergranular depth promotes strong chemical/mechanical bonding between the metal and the borosilicate glass typically used in the production of matched glass-to-metal seals. Furnace dew point, hydrogen concentration, residence time, and decarburization pretreatment were studied to determine their effect on oxide formation. A reproducibility study was performed to demonstrate the high consistency and repeatability of the system in an actual production environment. Bubble formation in the glass after sealing is discussed and is shown to be a result of overoxidation. All three steps of matched sealing (decarburiziug, oxidizing, and sealing) are studied with emphasis on control of the oxidizing step.

Bonding of metallic glass to crystalline metal

Abstract: A method of bonding a first thin crystalline metal to a second thin metal ch as metallic glass is disclosed. Initially, the metallic glass is coated with a thin thermal barrier layer. Next, the first metal is heated to a temperature sufficient for diffusion bonding. Finally, the metallic glass is maintained at ambient temperature as the metallic glass is diffusion bonded to the crystalline metal. The thermal barrier layer prevents the metallic glass from reaching a phase transition temperature during the diffusion bonding. Consequently, a composite product having a base layer of crystalline metal and an outer layer of metallic glass is produced. Preferably, the diffusion bonding is produced by evacuated roll-bonding and the coating is attached to the metallic glass by electroplating. A plurality of metallic glass layers and crystalline metal layers can be bonded together to produce a sandwiched composite product.

Anodic bonding of gallium arsenide to glass

Abstract: We describe a modified anodic bonding technique for hermetic sealing between GaAs and glass, the modification being called for by the formation of a nonadherent oxide layer during the bonding process. We show that this can be avoided by prebaking the glass and performing the bonding operation in a reducing atmosphere. With this technique, strong, hermetic seals can be produced. Parameter dependence has been studied theoretically by solving the continuity equation for a one‐dimensional model of the experimental situation. Experimentally, the bonds were evaluated with a number of methods, giving support for a model consisting of a high‐field, sodium‐depleted zone in the interface region during bond formation. The described technique is of particular interest for optoelectronic devices requiring transparent and hermetic seals.

Glass-bonded magnetic head having diffusion barriers

Abstract: A magnetic head (32) includes a magnet core (30) of ferrite and a layer of a bonding material (28) consisting of glass in the gap-forming area of the magnet core (38). In order to ensure that the ferrite is not attacked by the glass during the bonding process and that the temperature adjustment during the bonding process is not too critical, double layer diffusion barriers are provided between the layer of bonding material (28) and the core parts (10), (10'), respectively. Each barrier is formed by a layer of silicon nitride (26) on the side of the bonding layer (28) and a layer of silicon oxide (24) on the side of the core.

Glass-bonded magnetic head and method of manufacturing same

Abstract: A magnetic head (32) having a magnet core (30) of ferrite and a layer of a bonding material (28) consisting of glass in the gap-forming area of the magnet core (38). In order to ensure that in the one hand the ferrite be not attacked by the glass during the bonding process and that on the other hand the temperature adjustment during the bonding process is not too critical, double layer diffusion barriers are provided between the layer of bonding material (28) and the core parts (10) and (10'), respectively, which barriers are formed by a layer of silicon nitride (26) on the side of the bonding layer (28) and a layer of silicon oxide (24) on the side of the core parts (10) and (10'), respectively.

Magnetic head and its manufacture

Abstract: PURPOSE:To easily obtain an excellent magnetic head having no influences of bonding agents in a short time, by installing thin glass plates or glass layers to the gap part of cores made of a metallic magnetic material and by directly uniting the glass plates and the cores with each other without using any bonding agents. CONSTITUTION:Cores 2 and 2 made of a metallic magnetic material, such as permalloy, sendust, etc., and thin glass plates 5 and 5 are directly united with each other in such a way that the glass plates 5 and 5 are put between the cores 2 and 2 and an electric current is passed through them by using the cores 2 and 2 as anodes and by connecting the glass plates 6 and 6 to a cathode of a power source while they are heated by a heater or in a furnace. It is also possible that a glass layer of SiO2, etc., is vacuum evaporated on the gap forming surface of the cores 2 and 2 instead of the thin glass plates, and then, both the cores are united with each other by the above mentioned anodic bonding method. In this way a magnetic head is manufactured without using any resin-made bonding agents, and thus, problems of adhesion of resin together with magnetic powder on tape, etc., and deformation of the gap part are eliminated.

Sealing glasses for electrochemical, electrical, electronic, and optical applications and production of seals between such glasses and base glasses.

Abstract: A sealing glass capable of forming strong, non-porous seals with glasses containing at least 10% by weight of an alkali metal oxide such as are used in the fabrication of the glass membranes utilized in sodium-sulfur and potassium-sulfur batteries consists essentially, expressed in mole percent on the oxide basis as calculated from the batch, of about 3-30% R2O and 60-95% B2O3, wherein R2O consists of at least one alkali metal oxide selected from the group of K2O, Rb2O, and Cs2O, the sum of R2O + B2O3 constituting at least 70 mole percent of the total composition, suitable for sealing to a base glass containing at least 10% by weight of an alkali metal oxide having a smaller alkali metal than an alkali metal oxide in said sealing glass, said sealing glass having a softening point below the annealing point of the glass to be sealed and a coefficient of thermal expansion closely compatible with that of the base glass. In the sealing glasses Al2O3 may be substituted for up to one-half the B2O3 content on a molar basis. Exchange of large alkali metal ions from the sealing glass for the smaller alkali metal ions of the membrane glass may take place.