Abstract: On production of a component, two primary pieces must often be fixed together to give one piece. In order to achieve the above, it is important that the two primary pieces are oriented in a particular manner during the fixing process, which provides some difficulties. According to the invention, a plug body is fixed to the component by a mounting, whereby the position of the plug body relative to the component remains unchanged during a fixing process.

Abstract: Methods and associated apparatus are disclosed for use in mounting particles on and de-mounting particles from a substrate having an array of tacky and non-tacky areas. The particles can be either electrically conducting or electrically non-conducting. Selection of electrically conducting particles is preferred. The substrate having an array of tacky and non-tacky areas can either be electrically non-conducting (e.g., a dielectric substrate) or electrically-conducting. The methods involve use of first and second electrode plates with the substrate therebetween, the plates having applied thereto a direct current potential, which potential in preferred embodiments is reversed in polarity for a number N of cycles. Methods and articles are disclosed using an electrically conductive surface adjacent the tacky and non-tacky areas to minimize static buildup on the particles and tacky and non-tacky areas.

Abstract: In order to apply solder material (20) to a workpiece (1), compressed gas is guided through a bore hole (5) of a capillary (3). A pressure sensor (13) situated in the bore hole (5) measures the dynamic pressure of the compressed gas. As soon as the tip (12) of the capillary approaches the workpiece (1), the dynamic pressure increases and is used as a measure for the distance between the tip (12) of the capillary (3) and the workpiece (1), enabling the feed motion of the capillary to be controlled.

Abstract: Methods for placing conductive spheres on prefluxed bond pads of a substrate using a stencil plate with a pattern of through-holes positioned over the bond pads. Conductive spheres are placed in the through-holes by a moving feed mechanism and the spheres drop through the through-holes onto the bond pads. In one embodiment, the feed mechanism is a sphere hopper which crosses the entire through-hole pattern. In another embodiment, a shuttle plate fed spheres from a reservoir and reversibly moves about one-half of the pitch, moving from a non-discharge position to a discharge position.

Abstract: A brazing filler metal sheet is prepared. The brazing filler metal sheet includes a brazing filler metal layer, a sticking material layer, and a released paper. The brazing filler metal layer includes a brazing filler metal. A coating material layer is laminated on the brazing filler metal layer. The coating material layer includes a mixture of coating material particles and a binder. As the coating material particles, MCrAlY particles and abrasive particles are used. The coating material layer is then dried, and the brazing filler metal sheet is cut (step S4), and adhered to a rotor blade. The rotor blade is heated, to melt the brazing filler metal. The brazing filler metal diffuses due to the heat treatment holding process. A solidified layer is then formed by cooling. This solidified layer is subjected to blasting to allow the cubic boron nitride particles to protrude.

Abstract: A method of manufacturing a heat dissipating device, the method includes steps: a) affording a heat pipe, a solid solder bar and a heat sink, wherein the heat sink includes a base defining a groove at a side thereof; b) placing the solder bar and the heat pipe, in turn, into the groove of the heat sink; c) heating to melt the solder bar and simultaneously pressing the heat pipe to have an outer surface of the heat pipe coplanar with said side where the groove is defined; and d) cooling to achieve the heat dissipating device wherein the solder bar is evenly distributed between the heat pipe and the base.

Abstract: A method and structure are provided for implementing a column attach coupled noise suppressor for a solder column structure of the type used to join a substrate to a circuit card. The electrical noise suppressor structure includes a plurality of elongated through openings that are arranged in a predefined pattern. The elongated through openings have electrically conductive sidewalls and are electrically connected together. The predefined pattern of the elongated, electrically conductive through openings corresponds to a layout of solder columns. The solder columns are attached at one end to either a substrate or a circuit card and are inserted through the elongated through openings of the electrical noise suppressor structure, spaced apart from the electrically conductive sidewalls. Then the solder columns are attached at the other end to the other one of the substrate or circuit card.

Abstract: A method and structures are provided for implementing an impedance-controlled coupled noise suppressor for a differential interface solder column array used to join a substrate to a circuit card. The impedance-controlled coupled noise suppressor structure includes a plurality of elongated through openings that are arranged in a predefined pattern with one or more of the through openings receiving a differential signal pair of solder columns. The elongated through openings have electrically conductive sidewalls and are electrically connected together. The predefined pattern of the elongated, electrically conductive through openings corresponds to a layout of solder columns. The solder columns are attached at opposite ends to a substrate and a circuit card. An electrical connection is provided between the impedance-controlled coupled noise suppressor structure and an image return current path of the circuit card.

Abstract: A method for forming a tool 10 and a tool 10 which is comprised of several selectively coupled sectional members, such as members 12, 16, which are placed upon a heat resistant surface 20. A sealing material 24, such as copper in a solid molecular state, is placed around the periphery of the tool 10. The copper in a solid molecular state 24, the heat resistant surface 20, and the tool 10 are placed within a heat source which transforms the copper in a solid molecular state 24 into liquid which flows within the gaps, such as gap 41 and within knife edges 26, 28 which exists within the tool 10. After the copper 24 cools, the cooper 24 reinforces and strengthens the tool 10.

Abstract: There is provided a mask for use in printing solder on a plurality of terminals formed on a substrate so as to correspond to a plurality of terminals of an IC package. The mask has openings through which the solder is applied, and the openings are larger than the terminals. Although a wiring line adjacent to the terminals may be covered with the solder, a reflow process causes the solder to be divided into a first portion and a second portion, thus preventing short-circuits between the wiring line and the terminals.

Abstract: Methods and apparatuses for bonding solder balls to bond pads are described. In one embodiment, portions of a plurality of solder balls are placed within a frame and in registered alignment with individual bond pads over a substrate. While the ball portions are within the frame, the balls are exposed to bonding conditions effective to bond the balls with their associated bond pads. In another embodiment, a frame is provided having a plurality of holes sized to receive individual solder balls. Individual balls are delivered into the holes from over the frame. The balls are placed into registered alignment with a plurality of individual bond pads over a substrate while the balls are in the holes. The balls are bonded with the individual associated bond pads. In another embodiment, a frame is provided having a hole. A solder ball is provided having an outer surface.

Abstract: A method for metallurgically joining a tube to a member. A tube having a flange is obtained, and a member is obtained. A welding/brazing electrode wheel is obtained having an axis of rotation and having a rim. The tube and the member are positioned with the flange contacting the member directly and/or indirectly through an intervening welding/brazing joining material. The rim of the electrode wheel is positioned in direct contact with the flange. A resistance welding/brazing current path is created through the flange and the member using at least the electrode wheel creating a seam weld/braze zone which includes at least some of the flange and at least some of the member. During the current path creation step, the electrode wheel is rotated about the axis of rotation.

Abstract: A ribbon of color A metal is combined with a thin layer of soldering alloy, bent and soldered to form a tube, it is then filled with a core of color B metal. The compound is then drawn and/or laminated until it is transformed into a long ribbon or into a wire, externally of color A and internally of color B. The filled ribbon or wire is wrapped like a solenoid around a deformable support, like a metal mesh and stamped into the desired shape. The resulting two faced element is then ground in order to remove, all along a strip and following a line or in dots, the superficial part of color A until the core of color B is revealed. The bi-colored long element is then treated like a single body and allows the realization of precious bi-colored ornamental items.

Abstract: Reactive foils and their uses are provided as localized heat sources useful, for example, in ignition, joining and propulsion. An improved reactive foil is preferably a freestanding multilayered foil structure made up of alternating layers selected from materials that will react with one another in an exothermic and self-propagating reaction. Upon reacting, this foil supplies highly localized heat energy that may be applied, for example, to joining layers, or directly to bulk materials that are to be joined. This foil heat-source allows rapid bonding to occur at room temperature in virtually any environment (e.g., air, vacuum, water, etc.). If a joining material is used, the foil reaction will supply enough heat to melt or soften the joining material, which upon cooling will form a strong bond, joining two or more bulk materials.

Abstract: The invention is a method of bonding a ceramic part to a metal part by heating a component assembly comprised of the metal part, the ceramic part, and a compatible interlayer material such as titanium-nickel alloy placed between the two parts and heated at a temperature that is greater than the eutectic temperature of the interlayer material, where alloys, intermetallics or solid solution formed between the metal part and the metal interlayer material, but that is less than the melting point of either the ceramic part or the metal part. The component assembly is held in intimate contact at temperature in a non-reactive atmosphere for a sufficient time to develop a hermetic and strong bond between the ceramic part and the metal part. The bonded component assembly is optionally treated with acid to remove unwanted materials, to assure a biocompatible component assembly for implantation in living tissue.

Abstract: A method for producing diffusion bonds between components formed of tungsten heavy alloy (WHA) uses aid material to accelerate diffusion across the joint surfaces. The aid material consists of an alloy of palladium (Pd) with one or more of the secondary elements of nickel (Ni), iron (Fe), or cobalt (Co). The secondary elements are selected to correspond to the secondary elements present in the components. The diffusion bonding is carried out by placing diffusion aid material between the joint surfaces of adjacent components, applying a pressure across the joint surfaces, and processing the assembly through a thermal profile. Structures of WHA with complex shapes, interior volumes and/or large sizes can be formed. The joint properties are equal to or superior to those of the parent material of the components.

Abstract: The disclosure is a plural process to perform a solder ball attaching process that corresponds to the final of a ball grid array package manufacturing process. For example, flux and solder balls are exactly attached on solder ball pads of base frames on which base tapes having a number of land pattern groups are adhered. In the above state, the base frames are inserted into an adjacent reflow device to make the solder balls be attached on the solder ball pads. After the flux of the solder ball pad, on which the solder ball is attached, is removed, the base frames are stored in containers. To perform the base frame storing process in a very small space, the transfer course of the base frames is in the form of loop.

Abstract: A solder bump structure includes a contact pad, an intermediate layer located over the contact pad, a solder bump located over the intermediate layer, and at least one metal projection extending upwardly from a surface of the intermediate layer and embedded within the solder bump. Any crack in the solder bump will tend to propagate horizontally through the bump material, and in this case, the metal projections act as obstacles to crack propagation. These obstacles have the effect of increasing the crack resistance, and further lengthen the propagation path of any crack as it travels through the solder bump material, thus decreasing the likelihood device failure.

Abstract: A method for joining a tube to a member. A tube having a flange is obtained, and a member is obtained. The tube and the member are positioned with the flange contacting the member either directly or indirectly through an intervening joining material. The tube and/or the member are locally heated proximate the contact of the flange and the member without substantially heating the tube and/or the member apart from proximate the contact of the flange and the member. In one example, the local heating is welding, with or without a filler material, such as resistance welding, laser-beam welding or electron-beam welding. In another example, the local heating is brazing. In an additional example, a curable adhesive joining material is placed on the flange and/or the member, wherein the adhesive is located between and directly contacts the flange and the member, and wherein the local heating cures the adhesive.

Abstract: A method for metallurgically joining a tube to a member. A tube having a flange is obtained, and a member is obtained. The tube and the member are positioned with the flange contacting the member directly and/or indirectly through an intervening welding/brazing joining material. The flange and/or the member is segmented and their contact is a segmented contact at spaced-apart contact areas between the flange and the member. A resistance welding/brazing current path is created,through the tube and the member at a first contact area creating a first weld/braze zone which includes at least some of the flange and at least some of the member. Then, a resistance welding/brazing current path is created through the tube and the member at a different second contact area creating a second weld/braze zone which includes at least some of the flange and at least some of the member.

Abstract: A method of brazing stainless steel components to form a complex shape such as an impeller. The method includes the steps of providing the stainless steel components shaped and formed from a selected stainless steel alloy; providing a brazing alloy having a selected composition and compatibility with stainless steel; heating the stainless steel components and brazing alloy for a controlled time to a liquidus temperature to effect brazing; cooling the stainless steel components and brazing alloy to a quench temperature substantially lower than the liquidus temperature of the brazing alloy to provide a tensile strength of greater than about 20 Ksi in the brazing alloy; and quenching the assembly from the quench temperature to a temperature of less than about 400° F. in a given time to provide a brazed assembly free of distortion and cracks with desired mechanical properties in the stainless steel components by virtue of the thermal treatment.

Abstract: A solder deposition method according to the present invention comprises the steps of: (1) providing a solder slab; (2) providing a complementary means having a plurality of through holes; (3) providing a circuit element, which is composed of an insulating body and a plurality of embedded conducting terminals; (4) placing the circuit element under the complementary means and the solder slab above the complementary means, and injecting a plurality of solder bits taken from the solder slab by a punching device through the complementary means into the solder-retaining units of the conducting terminals. This method is advantageous in the simplicity of soldering instrumentation and process, which significantly reduces production costs.

Abstract: A method of providing turbulation on the inner surface of a passage hole (e.g., a turbine cooling hole) is described. The turbulation is first applied to a substrate which can eventually be inserted into the passage hole. The substrate is often a bar or tube, formed of a sacrificial material. After the turbulation is applied to the substrate, the substrate is inserted into the passage hole. The turbulation material is then fused to the inner surface, using a conventional heating technique. The sacrificial substrate can then be removed from the hole by various techniques. Related articles are also described.

Abstract: A solder ball attachment system for manufacturing an integrated circuit or the like is disclosed. The solder ball attachment system includes a flux station to apply flux onto a substrate and a solder ball placement station to place solder balls onto the flux on the substrate. The solder ball attachment system further includes a conveyor assembly to move the substrate between the flux station and the solder ball placement station.

Abstract: The invention provides a magnetic head capable of positively preventing electrostatic breakdown of an MR magnetic head device, and a method of manufacturing the magnetic head. A circuit board comprises at least a pair of leads for constructing a circuit, lands connected respectively to the leads, and solder bumps formed respectively on the lands. The solder bumps are arranged in an adjacent relationship and, when the solder bumps are crushed, peripheral portions of the solder bumps are pressed or spread so as to overlap with each other. The magnetic head includes the circuit board.

Abstract: A lead free solder hierarchy for use in the second level solder connection of electronic components such as joining an electronic module to a circuit board. An off-eutectic solder concentration of SnCu or SnAg is used for the module side connection. This off-eutectic solder contains sufficient intermetallics to provide the module side connection with a robust second level assembly and rework process. The off-eutectic composition provides an inter-metallic phase structure in the module side fillet during assembly. The inter-metallic phase structure eliminates problems of tilt and collapse during second level assembly and aids in rework by providing a more cohesive joint allowing removal of the columns from the board without simultaneous removal from the module.

Abstract: A new type of suspension circuit electrical bonding pad for electrically and mechanically connecting the magnetic recording head is described. The new type of bonding pad will serve as the joint material as well as the joint interface. Thus, there is no need to apply the conductive material in between the bonding pads and the magnetic recording head terminals, consequently reducing the process leading time and simplifying the magnetic recording head assembly process.

Abstract: A process and apparatus for manufacturing Solid Solder Deposit-Printed Circuit Board (SSD-PCB) by melting dry solder powder previously deposited on a pocketed-PCB 20. The process and apparatus utilize as heat source an electrically heated conveyor wire mesh 76 instead of a reflow oven. This invention, unlike the prior art for producing SSD-PCB, can readily utilize dry solder powder in conjunction with flux layers 116 separately deposited on top of the conveyor wire mesh 76 thereby excluding the use of solder paste and associated paste printing equipment. Specifically the invention reduces the manufacturing cost because: shortens manufacturing time, reduces manufacturing energy consumption and requires less manufacturing equipment than prior art.

Abstract: Methods and associated apparatus are disclosed for use in mounting particles on and de-mounting particles from a substrate having an array of tacky and non-tacky areas. The particles can be either electrically conducting or electrically non-conducting. Selection of electrically conducting particles is preferred. The substrate having an array of tacky and non-tacky areas can either be electrically non-conducting (e.g., a dielectric substrate) or electrically-conducting. The methods involve use of first and second electrode plates with the substrate therebetween, the plates having applied thereto a direct current potential, which potential in preferred embodiments is reversed in polarity for a number N of cycles. Methods and articles are disclosed using an electrically conductive surface adjacent the tacky and non-tacky areas to minimize static buildup on the particles and tacky and non-tacky areas.

Abstract: In the conventional bump forming method that can be applied to a semiconductor device in which a large number of bumps are required to be formed, there are various limitations on the material of which the bumps are made, due to enough cubic volume of bumps and to small scattering of the bump height. According to the invention, solder balls and a tool having a large number of through-holes are used, and under the condition that the through-holes of the tool are aligned with the pads of the semiconductor device, the solder balls are charged into the through-holes, pressed to be fixed on the pads, and then reflowed to form bumps.

Abstract: Methods and apparatuses for bonding solder balls to bond pads are described. In one embodiment, portions of a plurality of solder balls are placed within a frame and in registered alignment with individual bond pads over a substrate. While the ball portions are within the frame, the balls are exposed. In another embodiment, a frame is provided having a plurality of holes sized to receive individual solder balls. Individual balls are delivered into the holes from over the frame. The balls are placed into registered alignment with a plurality of individual bond pads over a substrate while the balls are in the holes. The balls are bonded with the individual associated bond pads.

Abstract: Objects of the present invention are to provide a laminated heat resistant alloy plate has a large area, and to provide a manufacturing method therefor. The laminated heat resistant alloy plate according to the present invention is obtained by brazing a Ni alloy plate having plural striae formed thereon at a predetermined interval and a plate which is made of a material the same as or different from that of the Ni alloy plate with a sheet of Ni solder which is amorphous and does not contain organic binder.

Abstract: A solder bump fabrication method is disclosed. First, a printed circuit board, having a plurality of devices, is provided. A material is formed on the printed circuit board, and it is disposed between pins of the devices to prevent the devices from short-circuiting due to the solder bumps. Then, the solder bumps are formed on the pins of the devices so that the devices are fixed on the printed circuit board. The printed circuit board is passed through an infrared oven to melt the solder bumps. The material separates the solder bumps attached to the pins of the devices so that the devices are prevented from short-circuiting.

Abstract: A method of attaching solder balls to a BGA package using a ball pickup tool. An array of solder balls is formed on a first substrate for interconnecting with conductive sites on another substrate. The ball pickup tool picks up balls with a vacuum suction from a fluidized ball reservoir and utilizes a puff of gas to release the solder ball(s) carried thereon to conductive sites of a substrate for bonding thereto. In another embodiment, the bond pads of a substrate are coated with a flux or adhesive and lowered into a fluidized ball reservoir for direct attachment of solder balls.

Abstract: Lead-free solder alloys based on a Sn—Ag—Mg system are disclosed. The alloy compositions have a melting temperature close to 183° C. and a similar surface tension to that of Sn—Pb solder, and can thus be a readily substituted for conventional Sn—Pb solders. P may be added to the alloy compositions to reduce its tendency of oxidation.

Abstract: Systems and methods for forming a seal between members of an assembly are disclosed. In one embodiment, a seal is formed between a first member and a second member by establishing within the members a bounded volume and creating within the bounded volume a pressure differential with respect to the ambient pressure outside the bounded volume. The pressure differential results in a uniformly applied clamping force to the members thereby creating a reliable seal. A sealing member (such as solder, epoxy, or other sealant) is positioned between the first and second members and the resulting assembly is mechanically positioned such that heat can then be applied to melt the solder. Concurrently, the pressure differential is created which allows the externally applied mechanical positioning to be relaxed while the members are being sealed together. This system and method can be used to create hermetic seals.

Abstract: A circuitized substrate and a method of making the circuitized substrate is provided. The circuitized substrate includes a substrate having a conductive pad thereon. A first layer of solder enhancing material is positioned on the conductive pad, the first layer of solder enhancing material includes a first region and a second region positioned relative to the first region. A solder member is positioned on the first region of the first layer of solder enhancing material. A second layer of solder enhancing material is positioned on the solder member and on a portion of the second region of the first layer of solder enhancing material. The circuitized substrate may be used in the fabrication of an electronic package.

Abstract: There is provided a mask for use in printing solder on a plurality of terminals formed on a substrate so as to correspond to a plurality of terminals of an IC package. The mask has openings through which the solder is applied, and the openings are larger than the terminals. Although a wiring line adjacent to the terminals may be covered with the solder, a reflow process causes the solder to be divided into a first portion and a second portion, thus preventing short-circuits between the wiring line and the terminals.

Abstract: A method and apparatus for soldering terminal ends of an antenna embedded in a plastic smart card to contact terminals of an IC module disposed on the card are shown. The enamel coated antenna terminal ends are pre-coated with solder with a heater having horizontal opening with melted solder retained therein. The solder pre-coated terminal ends are maintained in a secured contact with the terminal contacts of the IC module by heating coils mounted at a free front end of two pivotal elongated cantilever arms. A piece of predetermined amount of solder is dropped into the cavity of each heating coil, and the heating coils are actuated with a low electrical current to generate a concentrated intense heat to meld the piece of solder to form secure permanent solder joints between the terminal ends of the antenna to the contact terminals of the IC module.

Abstract: A method of forming a meltable material at a joint between telescopingly engaged male and female elements, with the female element having a joint surface that surrounds a joint surface of the male element. The method includes the steps of: placing a ring of the meltable material around one of the male and female elements at a first location spaced from the joint; heating the male and female elements at the joint to a temperature at which the meltable material melts; sliding the ring of meltable material from the first location to a second location; with the ring of meltable material at the second location and the male and female elements of the joint at a temperature at which the meltable material melts, causing the meltable material to flow between the male and female joint surfaces; and cooling the male and female elements at the joint to solidify the meltable material between the male and female joint surfaces.

Abstract: A solder ball attracting mask which is mounted on a suction apparatus for sucking a plurality of solder balls under vacuum so as to place the solder balls on electrodes of an electronic component and formed with a plurality of through-holes for attracting the solder balls thereto, with the solder ball attracting mask having a principal face engageable with the solder balls and a rear face engageable with the suction apparatus such that the through-holes extend through the solder ball attracting mask from the principal face to the rear face, the through-holes each including a funnellike attraction area for attracting the solder ball thereto, which reduces its diameter gradually from the principal face towards the rear face up to a suction port and a suction hole which has a diameter larger than that of the suction port and extends from the suction port to the rear face to define a suction space.

Abstract: A backing plate of Ti for supporting a Ti sputtering target is formed of at least two components welded together. The backing plate is welded by interposing a Cu or Zr foil or powder between faces to be welded, and then heating the assembly to a reaction temperature high enough to melt one of the Ti and Cu or Zr to produce a liquid phase. The heating temperature is retained for a time long enough to permit diffusion of the Cu or Zr into the Ti to produce a liquid phase diffusion weld. By permitting diffusion to occur, a separate metallic compound is not produced at the welding face. In effect welding is accomplished without producing a welding face, whereby no interface exists in the finished weld. The resulting weld has a strength substantially equal to the strength of the Ti material, and very good welding qualities.

Abstract: A laser diode bar, solder preform and heat sink are assembled prior to reflowing the solder in a manner to prevent molten solder from being drawn by capillary action over the light emitting end of the diode bar. A recessed pin 30 locates the ends of the laser bar and solder preform with respect to an edge of the heat sink so that the laser bar and solder preform overhang the heat sink edge by respective amounts. When molten, the solder will not be drawn by capillary action to obscure the light emitting end of the laser diode bar.

Abstract: A highly heat-resistant laminated component for a fusion reactor has at least of a plasma-facing area made of tungsten or a tungsten alloy, a heat-dissipating area of copper or a copper alloy with a mean grain size of more than 100 &mgr;m, and an interlayer of a refractory metal-copper-composite. The refractory metal-copper-composite has a macroscopically uniform copper and refractory-metal concentration progression and a refractory metal concentration of between 10 vol. % and 40 vol. % over its entire thickness.

Abstract: A process and apparatus for forming fusible solder material mounted on a substrate with the use of a tool having a treatment surface with selected shape. The solder material is heated sufficiently to cause fusing after which the tool is moved such that the treatment surface enters the fused material. The material is allowed to cool to permit re-solidification, after which the treatment surface is withdrawn from the solder, leaving the imprinted shape. The treatment surface is made of material that is not wettable by the solder.

Abstract: In a method of soldering the surfaces of a component (11) to a substrate (12), a solder preform (15) is located in the gap between the surfaces. The solder is heated and an over pressure applied to move the surfaces together whilst the solder is molten. Abutments (17) between the surfaces limit the spacing between them. A trapped void (18) is decreased in volume as the pressure is applied. The method is particularly applicable to monolithic microwave integrated circuits (MMIC) and reduces void areas in joints.

Abstract: A connecting method of a wheel rim of a bicycle includes the following steps: forming a wheel rim, inserting an inner connecting member between two abutment ends of the wheel rim, connecting the two abutment ends, heating, packing, permeating, and returning. Thus, the structural strength of the wheel rim is enhanced, thereby increasing the lifetime of the wheel rim. In addition, the connecting seam of the two abutment ends will not form a protruding rough bur, so that it is unnecessary to perform a secondary working process to grind the surface of the connecting seam of the two abutment ends, thereby simplifying the working process of the wheel rim, and thereby decreasing costs of fabrication.

Abstract: Method for controlling the deposition of solder on a base metal or substrate is disclosed. The method comprises applying an attaching flux and finishing flux to a substrate, placing a preform thereon and subjecting the same to reflow conditions. The finishing flux is applied to solubilize the normally insoluble corrosive residues that would occur when the attaching flux is subjected to reflow conditions with the preform and substrate. Alternatively, the attaching flux may be applied to the preform and substrate before undergoing reverse reflow conditions and then the finishing flux is applied to the solder deposit and substrate and the same subjected to second reflow conditions. After each method, the residues left from the attaching flux which are solubilized by the finishing flux, are cleaned by washing with a typical solvent.

Abstract: The object of this invention is to employ a solder alloy comprising tin/lead/silver in order to provide a wider solidification range and achieve balance between the surface tensions of both side of a small leadless component. The expanded solidification range slows the melting and wetting time so as to balance the surface tension of the molten solder, and in turn reduces the tombstoning frequency. The preferred Ag concentration is 0.2-0.5% in weight, the more preferred Ag concentration is 0.3-0.4% in weight. For reflow soldering of small leadless components, the pastes made with the alloy compositions of Sn62.6Pb37Ag0.4 and Sn63Pb36.6Ag0.4 results in improvements in tombstoning.

Abstract: The interfacial joint area of a target/backing plate assembly is sealed so as to inhibit the migration of air and/or water vapor that may be present or trapped along the interfacial surfaces. A pool or bead of molten solder is placed along the interfacial joint and moved continuously around the full 360° circumference of the assembly so as to cover and seal the boundary area. The solder is melted, preferably, by e-beam welding in a vacuum or the like.