Abstract: A flux composition for brazing of an aluminum material which can feed a proper amount of flux to an area to be joined at the time of brazing and at the same time can improve working environment, and a method for brazing of an aluminum material. The method comprises: coating an aluminum material to be joined with a flux composition comprising 0.5 to 25 parts by weight of a polymeric compound having a number average molecular weight of 50000 to 5000000 and comprising repeating alkylene oxide units, 5 to 30 parts by weight of a fluoride flux, and water added in such an amount as will provide a total amount of the composition of 100 parts by weight; heating the coated area to remove water; heating the coated area to decompose and remove the polymeric compound; and then conducting heating for brazing.

Abstract: A flux formulation without a surfactant is available for use in the assembly of electronic circuit boards as a no-clean formulation. The formulation includes a flux solution having a fluxing agent consisting essentially of one or more weak organic acids and a solvent consisting essentially of water. The flux solution serves to transport the fluxing agent before deposition thereof upon a soldering site for reliability improvement engendered by a lack of hygroscopic residue and for avoidance of environmental degradation engendered by a lack of volatile organic chemicals (VOC's). The method includes the steps of heating the flux solution and dispersing it as a fine spray.

Abstract: A scale formation-inhibitory agent used in a welding treatment comprises a polymer selected from the group consisting of polymers having oxygen atoms in the main chain and polymers capable of being thermally depolymerized. The scale formation-inhibitory agent can inhibit the formation of scale on the surface of a metal part to be welded during a welding treatment.

Abstract: A method of mounting an integrated circuit having a plurality of leads on a printed circuit board (PCB), by: removing foreign substances on the PCB; spreading a flux on lead patterns formed on the PCB; aligning the leads of the integrated circuit on the lead patterns on the PCB on which the flux is spread; soldering the leads and lead patterns by covering the part of a semiconductor chip of the aligned integrated circuit using a holding block and radiating an optical beam onto the whole surface thereof; and cooling the holding block and PCB which has been soldered, which prevents shorts and a poor contact generated by an earlier method. As the quality of soldering is enhanced and the lead is not pressured when soldering, the confidence of the integrated circuit after mounting is also enhanced. Moreover, by soldering all of the leads at one time, the operational time can be reduced.

Abstract: An improved method of coating the welded seam of a metal tube comprising heating the weld area only of the metal tube to a first temperature which is less than the melting temperature of the protective metal coating, applying the protective metal coating over the seam and heating the entire tube preferably with a full body induction coil to a second temperature which is at least equal to the difference between the first temperature and the melting temperature of the metal coating, such that the temperature of the seam area is heated to a temperature equal to or greater than the melting temperature of the metal coating, whereby the metal coating firmly adheres to the welded seam.

Abstract: The forming oil degreasing step and flux coating step are reversed as part of a basic fluxed heat exchanger brazing process. This allows the fluxed parts to be thermally degreased concurrently with the braze oven workpiece preheat process, eliminating a separate degrease step and apparatus entirely. Surprisingly, and contrary to all teaching as to electrostatic dry power coating, powdered flux was found to electrostatically bond to an oily surface as well as, or even better than, an oil free surface.

Abstract: The invention relates to a method for dry cleaning or dry fluxing metallic surfaces before, during, or after a reflow soldering operation. The metallic surfaces that are dry cleaned or dry fluxed include (1) the metallic substrate on which an at least partially metallic, electronic component is to be mounted, (2) the solder paste, and (3) the metallic portions of the electronic component. The method comprises treating the metallic surface with a gaseous treatment atmosphere comprising unstable or excited gaseous species, and is substantially free of electrically charged species.

Abstract: A method and system for introducing flux onto at least one surface of a solder pump achieve their objects as follows. A solder pump nozzle is submerged into a flux reservoir. In response to such submersion, the flux in the reservoir is actively introduced into the solder pump nozzle. In one embodiment, the active introduction is achieved by creating a negative pressure in a solder pump nozzle such that flux fills a vacated volume. The created negative pressure is produced by moving a solder column, contained within the solder pump nozzle, under the influence of an applied electric current and an applied magnetic field.

Abstract: A method for aluminum brazing, in which the addition of a solder is no longer necessary. For this purpose a flux is used which contains 6 to 50 wt-% of potassium fluorosilicate and 50 to 94 wt-% of potassium fluoroaluminate. The flux can be used, for example, in the form of an aqueous suspension or paste.

Abstract: A tool for soldering pin-in-hole electronic circuit components includes a tool plate with a set of via holes corresponding to the holes of a circuit board on which a circuit component is soldered. The board is aligned with the tool plate and hot gas is supplied through the set of plate vias to reflow solder in the board holes. The tool is particularly suitable for use in removing and replacing pinned circuit components. Use of particular gases (e.g., nitrogen) allows soldering to be carried out without the use of flux. Advantages of the tool are that it prevents burning the circuit board and/or unintentionally reflowing other circuit components mounted on the board (by directing hot gas only substantially onto the circuit board's solder-containing holes).

Abstract: A method for thermocompression bonding structures together including structures having different coefficients of thermal expansion, for example, thermocompression bonding optical diode arrays or other semiconductor structures to silicon substrates to form electronic or optoelectronic devices. The method includes aligning and contacting the structures to be interconnected, thermocompressing the structures via their contact pad elements at a bonding temperature, establishing an encapsulation temperature, applying an encapsulant material between the bonded structures, and curing the encapsulant material at the encapsulation temperature. Conventional bonding processes, which treat encapsulation as a separate step apart from bonding processes, melt the bonded assembly together and include at least one thermal cycle in which the bonded assembly is cooled to room temperature and then is re-heated to the encapsulation temperature before applying the encapsulant material.

Abstract: A flux formulation without a surfactant is used in the assembly of electronic circuit boards as a no-clean formulation. The formulation includes a flux solution having a fluxing agent consisting essentially of one or more weak organic acids and a solvent consisting essentially of water. The flux solution serves to transport the fluxing agent before deposition thereof upon a soldering site for reliability improvement engendered by a lack of hygroscopic residue and for avoidance of environmental degradation engendered by a lack of volatile organic chemicals (VOC's). The method comprises the step of heating the flux solution and dispersing it as a fine spray.

Abstract: In a heat exchanger having a plurality of tubes 2 alternately laminated with fins 3, header pipes 4 connected to and in communication with both ends of the laminated tubes, inlet and outlet connectors 8 connected to the header pipes to supply and receive a heat exchanging medium to and from an external equipment, and the heat exchanging medium meanders a plurality of times between the inlet and outlet connectors; a groove 15 is formed in one of the inlet and outlet connectors 8, on the rim of the piping connecting face of the connector having its piping connecting face 11 facing downward with respect to the vertical line during brazing, so as to prevent the flux from entering into the inside of the piping connecting face from the outside of the piping connecting face.

Abstract: A method for soldering is disclosed wherein parts to be soldered are passed sequentially into and out of a flux and a solder bath. The flux cleans the parts of surface debris, such as oxides, before the parts are immersed in the solder.

Abstract: A flux composition for use together with solder preforms, which comprises rosin, N-unsubstituted or N-substituted 2-pyrrolidone, and optionally a high boiling point ester solvent with a content of N-unsubstituted or N-substituted 2-pyrrolidone being 3-50% by weight and a content of the ester solvent being not greater than 30% by weight.

Abstract: A process of transferring a flux on electrodes of a semiconductor chip, a film carrier, or a substrate, the process comprising: using a transfer apparatus including a transfer baseplate having protrusions corresponding to said electrodes; dipping the tips of the protrusions of the transfer baseplate in a flux bath to cause the flux to stick to the tips; then aligning the protrusions of the transfer baseplate with the electrodes; and transferring the stuck flux onto the electrodes from the tips.

Abstract: A method of soldering used in fabricating an electronic circuit device employs an organic material supplied to at least one of the connecting members to be bonded. The connecting members are positioned in an oxidizing atmosphere, and heated in a nonoxidizing atmosphere to remove oxide and/or contamination layers present on the surface of presoldered portions or metallized bonding portions. By this method, fluxless soldering is performed, positional shifts are reduced, and high reliability of the soldering connections with reduction in residues after reflow are obtained.

Abstract: The invention provides a soldering flux for mounting circuit substrates, which is free from any organic solvent attributable to air pollution and dispenses with any washing step. The soldering flux is obtained by dissolving a rosin modified by an unsaturated organic acid according to the Diels-Alder reaction in an aqueous solvent. A volatile basic agent may further be contained in the flux.

Abstract: In a brazing method, a flux-mixed liquid is prepared by mixing a brazing flux with a quick-drying oil. The flux-mixed liquid, when it is spread to an aluminum or aluminum alloy work, fixes the brazing flux to the work by a quick-drying character of the quick-drying oil within a short time. Also, in the brazing method, the flux-mixed liquid is prepared by mixing the brazing flux with an aqueous solution in which a solid lubricant is melted in water. The solid lubricant melts in water at or above a prescribed temperature, and forms a film when the temperature is below the prescribed temperature. The flux-mixed liquid, when it is spread to the work, immediately forms the film due to a drop in temperature below the prescribed temperature and fixes the brazing flux to the work by the film within a short time.

Abstract: Multiple I/O pads are arranged in a pattern on a surface of an integrated circuit package, and an obstruction in the package prevents a planer solder flux mask from lying flat on the surface around the I/O pads. Such an obstruction can, for example, be a lid in the package which projects above the I/O pads, or it can be an encapsulant which covers a chip in the package and projects above the I/O pads. Despite the presence of the obstruction, solder flux is dispensed on the I/O pads of the integrated circuit package by the steps of --a) providing a pin block that has a base from which multiple pins project, and the ends of the pins match the pattern of the I/O pads; b) coating the ends of the pins with a solder flux; and, c) transferring a portion of the solder flux from the ends of the pins to the I/O pads by temporarily touching the coated ends of the pins against the I/O pads.

Abstract: An open-air brazing method for manufacturing an assembly including at least one aluminum based tube having an internal surface and an external surface, applying an Aluminum Association 4XXX aluminum based filler material to at least a portion of the external surface of the tube, disposing at least one aluminum based component adjacent the filler material, and applying a modified aluminum brazing flux to a joint between the at least one tube and the at least one component to form a precursor assembly, said brazing flux comprising cesium fluoride, lithium fluoride, or their mixture added into a potassium fluoaluminate flux in an amount of at least about 1% by weight of the modified flux. The method further comprises joining the at least one tube and at least one component together in an open-air brazing furnace whereby the temperature is raised from about 450.degree. C. to about 600.degree. C. in about 15 to 20 seconds.

Abstract: A process for preparing a solder bump can be prepared by the following procedure. The chip package was cleaned with an alkali or acid solution followed by Zn displacement (zincating)in a displacement solution which comprises NaOH, Z.sub.n o, potassium sodium tartrate and sodium nitrate. After zinc displacement the chip package was performed the electroless Ni--Cu--P deposit in the strong reducing solution which contains NaH.sub.2 PO.sub.2. The chip package deposited with Ni--Cu--P was then dipped into an organic solution as flux which is a mixture of the stearic acid and glutamic acid. Finally, dip soldering of the Ni--Cu--P deposited chip packages in a molten solder bath at a temperature 40.degree..about.80.degree. C. higher than the melting point of the corresponding Pb--Sn alloy.

Abstract: The invention provides a solder preform coated with a predetermined thickness of parylene which physically and chemically protects the preform, as well as a provides a unique optical interference coating which reflects at characteristic frequencies. When predetermined thicknesses of parylene are selected, the parylene coating provides an interference coating which causes the solder preforms to appear green, or gold, or blue in color. The parylene coating, which is otherwise colorless and transparent thus enables solder preforms to be visually distinguishable by alloy type (or customer) by the use of colors, or blends of colors. The invention further provides an effective method of visually verifying the reflow status of a solder preform during manufacturing by examining the color of the solder preform after heating.

Abstract: A method of joining an electronic component (10) provided with contact surfaces (12) to a substrate (11) comprising contact surfaces (14) via contact metal coatings (16, 17) formed between the contact surfaces and made of a solderable or weldable joining material (15), the electronic component and the substrate being pressed together and heated, and during the joining operation a layer (18) of a medium (19) containing a polyalcohol is disposed at least between the joining material (15) and the contact surfaces (12) of the electronic component (10) or the substrate (11).

Abstract: Brazing fluxes comprising a combination of a fluoroaluminate complex and selected metal fluorosilicates, including their method of manufacture and use, are disclosed.

Abstract: A heat exchanger assembly includes at least one tube having an internal surface and an external surface, a composition cladding having at least lithium and magnesium applied to either one of the internal surface and external surface of the tube, and at least one component disposed adjacent the composition cladding, whereby the tube and component are joined together during a controlled atmosphere brazing process.

Abstract: A method of brazing is described, the method comprising the steps of applying a layer of particles of an aluminum alloy filler material said particles having a coating of a flux-type material selected from the group comprising a compound of potassium fluoride and aluminum fluoride together, or other inorganic flux-type material, to at least one of said articles such that said particles are retained at or adjacent at least a part of the joint between said articles; heating to cause the flux-type material and said aluminum alloy filler material to melt and form a brazed joint.

Abstract: An absorber head picks up a plurality of soldering balls from a container, and is shifted horizontally toward a substrate. In the midway of this shift movement, the absorber head is stopped just above a flux storage and then lowered to soak the soldering ball in the flux stored in the flux storage, thereby applying each soldering ball with an adequate amount of flux. Thereafter, the absorber head is again shifted horizontally until it reaches the substrate. Then, the absorber head lowers the soldering ball applied with flux, so that each soldering ball is mounted on a corresponding electrode provided on the substrate. If any soldering balls are left in the flux storage due to failure of the pickup operation by the absorber head, such soldering balls are surely collected in a groove by wiping movement of a squeegee which is associated with the flux storage.

Abstract: A hot air circulation apparatus and method for wave soldering machines which heats air from a high-pressure air source and directs it at the flux applied to a printed circuit board. The heated and pressurized air also circulates air within the wave soldering machine to force the moisture out. A plurality of hot air knives are mounted adjacent heaters within the wave soldering machine and are coupled to the pressurized air source. The hot air knives include a hollow metal cylindrical member which conducts heat from the heater, and contain a plurality of orifices which increase the pressure of the air and direct the air at the flux.

Abstract: A solution (20) is dispensed onto bond pads (18) on a substrate (14). An integrated circuit component (12) that includes solder bumps (16) formed on component bond pads (30) is superposed onto the substrate (14) such that the solder bumps (16) rest against the bond pads (18). The solution (20) includes an anhydride compound that acts as a fluxing agent. The subassembly (11) is heated to a temperature sufficient to bond the solder bumps (16) to the bond pads (18) to form solder bump interconnections (26). During the bonding process, the fluxing agent substantially vaporizes and leaves virtually no residue on the substrate (14) to allow the component (12) to be effectively underfilled with a polymeric encapsulant (24).

Abstract: An absorber head 10 picks up a plurality of soldering balls 1 from a container 2, and is shifted horizontally toward a substrate 31. In the midway of this shift movement, the absorber head 10 is stopped just above a flux storage 32 and then lowered to soak the soldering ball 1 in the flux 34 stored in the flux storage 32, thereby applying each soldering ball 1 with an adequate amount of flux. Thereafter, the absorber head 10 is again shifted horizontally until it reaches the substrate 31. Then, the absorber head 10 lowers the soldering ball 1 applied with flux, so that each soldering ball 1 is mounted on a corresponding electrode 31a provided on the substrate 31. If any soldering balls 1 are left in the flux storage 32 due to failure of the pickup operation by the absorber head 10, such soldering balls 1 are surely collected in a groove 36 by a wiping movement of a squeegee 37 which is associated with the flux storage 32.

Abstract: A liquid flux using water instead of a volatile organic compound as the liquid carrier is used in a wave soldering process. Undesirable formation of solder balls, solder bridges and solder webbing is prevented by using an air knife to direct a vigorous jet of gas at the dielectric substrate in the preheating section.

Abstract: A method for depositing a tacking agent (18) onto a circuit-carrying substrate (e.g., a printed circuit board) (22) such that a regulated volume is simultaneously deposited at multiple substrate sites (24). A first input pressure, P1, introduced through a bladder inlet (12), is supplied to a compliant bladder (14) which is in contact with a plurality of transfer pins (16). The compliant bladder imparts a substantially equal force to each of the transfer pins. The pins are then dipped into a thin film of tacking agent and removed. Subsequently, the first input pressure, P1, is adjusted to a second input pressure, P2, sufficient to force the pins to a uniform maximum extension. Finally, the second input pressure, P2, is adjusted to a third input pressure, P3, which imparts a predetermined uniform force on each of the pins, and the pins are brought in contact with the printed circuit substrate deposition sites.

Abstract: A dispensing apparatus for applying a pulsed thin stream of flux to a surface such as a printed circuit board. The stream of flux is pulsed at a high rate to apply a thin layer of flux on the surface. The dispensing head consists of multiple orifices for applying the flux to the board. The streams of flux are angularly disposed and a pan is positioned for capturing flux which passes by the board. The board is conveyed by the dispensing head. Controls are incorporated for board sensing and identification, application width selection, precise pressure control, fluid flow monitoring and system safety conditions.

Abstract: A new flux composition, as well as corresponding methods for soldering electronic components to printed circuit boards, is disclosed. The new flux composition includes pimelic acid and two organic solvents. Significantly, the new flux composition leaves essentially no ionic residues at the completion of the soldering processes used to mount electronic components onto printed circuit boards.

Abstract: A solder reflow convection furnace employing flux collection and heating to minimize flux and solvent build up and gas densification to reduce input gas flow is disclosed. As solder melts in the furnace, an effluent of vaporized flux is driven off and can condense on cooler components. To minimize such condensation, the gas is directed through a cooling system in which the flux condenses, and the cooled, cleaned gas is directed into the furnace's product cooling section. In another embodiment, in which the gas in the furnace is recirculated, a cooling coil is located upstream of the recirculating gas mover to heat the primary gas. The vaporized flux condenses on the cooling coil, which can be readily removed and replaced. In another aspect of the invention, when the furnace employs a gas amplifier, the recirculating gas is cooled prior to reentry into the heating chamber, which increases its density and removes flux by condensation.

Abstract: An arrangement of applying flux in solid, liquid or gaseous form directly to the solder wave avoids prefluxing of printed circuit boards or other elements to be soldered or solder wetted. The process for wave soldering an element comprises the steps of forming a solder wave above a solder reservoir, applying a flux directly to the solder wave separately from a shield gas delivery means to blanket the solder wave, and conveying the element through at least a portion of the solder wave. The process is applicable to wave soldering under a shroud wherein a gas shield is supplied by diffusers under the shroud, the flux being applied by at least one gas applicator directly to the solder wave.

Abstract: A novel flux is provided for use in the low-temperature brazing aluminum materials of varied compositions, the flux being composed of a KCl--NaCl--BaCl.sub.2 base and 0.5-5.0 wt. % of LiF and/or 1.0-10.0 wt. % of ZnCl.sub.2 added to the base. A method of flux brazing a low-melting aluminum material is also provided, and the method is carried out by applying such a novel flux as well as a low-melting brazing agent to the aluminum material portions to be adjoined. The brazing agent is composed of an Al--Si--Zn alloy which contains 3-12% by weight of Si and 15-70% by weight of Zn.

Abstract: Low residue water-based soldering flux, and process and system for using the same. The flux includes a mixture of succinic, glutaric and adipic acid in water, and optionally a wetting agent. The flux is applied to a surface to be soldered. The flux is dried. The surface is soldered. The flux is applied at an application station, dried at a drying station and soldered at a soldering station.

Abstract: A method of applying a tacking agent to a printed circuit board. The printed circuit board (10) has a number of solder pads (12), and each solder pad is preclad with a layer of solder (14) between 0.02 and 0.3 mm thick. A plastic film (16) is temporarily adhered to the printed circuit board by a pressure sensitive adhesive. The plastic film has a number of apertures (22) that correspond to the solder pads, and is positioned so that the apertures in the film expose the solder coated pads. There is a breakaway tab (20) on the plastic film that is used to peel the film from the printed circuit board in a later operation. The film is roller coated with a high viscosity tacking agent (30) so that a layer of the tacking agent is applied to the exposed interconnect pads. The plastic film is then peeled cleanly away from the printed circuit board using the breakaway tab, leaving the tacking agent only on the solder pads.

Abstract: Fluxing and soldering terminals on a printed circuit board by an in-line process in which flux concentration is determined at specific locations laterally of the passline. At each of the positions infrared light is passed through a wall of flux which is being directed at the board. The infrared light becomes partly absorbed by materials in the flux and the unabsorbed light which passes through the wall of flux is used to generate signals corresponding to the different wavelengths of unabsorbed light at each of the locations. This enables a determination to be made of the flux concentration at each location. The signals are preferably used to effect a change in the flow rate of flux at any specific location so as to control the amount of flux deposited upon the board. Particularly useful for "no-clean" flux applications.

Abstract: Fluxing and soldering terminals on a printed circuit board in an in-line process in which a wall of flux is directed against a surface of the board which moves in inclined manner as it passes through a fluxing station and towards a soldering station. The process controls flux application to decrease the amount of flux applied from the leading end to the trailing end of the board, the board inclination resulting in flow of flux to redistribute it towards providing a constant flux thickness for the soldering step. Particularly useful for processes involving "no-clean" flux application where residual flux after soldering is to be avoided because of potential electrical problems.

Abstract: A non-toxic, non-corrosive liquid soldering flux consists essentially of a solution of citric acid in water. This unique flux produces solder joints of high metallic luster and excellent quality. Disposal presents no health hazards, and clean-up of flux residues is accomplished using only water.

Abstract: An improved flux composition is provided which is formulated for use in the brazing of aluminum alloy components, such as in the assembly of brazed heat exchanger units used in automotive applications. The flux composition is in a concentrated form, permitting its selective application to the joint surfaces of a heat exchanger's subcomponents, and contains a flux material which consists essentially of potassium tetrafluoroaluminate, a carrier system such as a glycerol-ethylene glycol system, a binder, and a liquid medium such as water. Most preferably, the potassium tetrafluoroaluminate constitutes at least about 96 percent of the flux material, and the binder is xanthan which substantially prevents the flux composition from separating during storage. The flux composition does not contain potassium aluminum fluoride.

Abstract: A flux formulation for use in the assembly of electronic circuit boards having components to be joined by soldering. The formulation comprises a medium which acts as a carrier and solvent for the fluxing agent, which includes in a preferred embodiment supercritical carbon dioxide. The formulation also includes a fluxing agent, being at least partially soluble in the supercritical carbon dioxide which serves to transport the fluxing agent before deposition thereof upon a soldering site. The supercritical fluid is delivered through a nozzle to the circuit board, the supercritical condition being maintained until the supercritical fluid is discharged from the nozzle. The fluxing agent at least partially loses its solubility in the fluid thereupon and is transported to the board by a stream of carbon dioxide gas. Also disclosed is a method for delivering a flux formulation to the electronic circuit board.

Abstract: A no-VOC or low-VOC no-clean flux formulation for use in the assembly of electronic circuit boards having a conformal coating. The formulation comprises a solvent, a water-soluble weak organic acid, a halide-free, non-ionic surfactant, and a biocidal co-solvent. The formulation is compatible with the conformal coating, permits no or low VOC emissions into the environment, and eliminates post-soldering cleaning steps.

Abstract: A soldering process for use with solder clad printed circuit boards (10) uses a pin transfer means to apply a tacking agent to the substrate. An array of pins (24) is dipped into a film of tacking agent (22). The pins are removed from the tacking agent (26) carrying with them a predetermined amount of tacking agent. The pins are then contacted (27) to the printed circuit board and removed (28). During this process, a predetermined amount of tacking agent is deposited at selective locations on the printed circuit board. A component is placed (30) on the printed circuit board in the tacking agent and the circuit board and component are heated (40) in order to reflow the solder and effect the solder joint between the component and the board.

Abstract: A hot air circulation apparatus and method for wave soldering machines which heats air from a high-pressure air source and directs it at the flux applied to a printed circuit board. The heated and pressurized air also circulates air within the wave soldering machine to force the moisture out. A plurality of hot air knives are mounted adjacent heaters within the wave soldering machine and are coupled to the pressurized air source. The hot air knives include a hollow metal cylindrical member which conducts heat from the heater, and contain a plurality of orifices which increase the pressure of the air and direct the air at the flux.

Abstract: Apparatus and methods for a system and process for applying a flux coating to a circuit board by pulsing an airless spray gun on and off to achieve excellent circuit board through-hole penetration and uniform film thickness. An overspray collection system is provided which reduces overspray and increases material utilization and transfer efficiency. A gun positioning mechanism, which can be automated, accurately locates the gun relative to the circuit board.

Abstract: An apparatus and process prepares surfaces on components, boards and the like for assembly and solder joining. Oxides and other coatings can be removed from surfaces to be soldered without having to solder coat surfaces prior to joining. A polymer and an activator combination is applied to the surfaces, the polymer being thermally de-polymerizable and the combination removing oxides from the surfaces. The surfaces are heated after application of the polymer and activator to de-polymerize the polymer. Solder is then applied to solder join the surfaces.