A method for assembling components includes assembling a first component including solder bumps with a second component including connectors. The assembly of the components is preceded by pre-treating the first and second components wherein the solder bumps are contacted with a pre-treatment liquid configured to at least partially remove an oxide layer initially present on the solder. The pre-treatment liquid is an aqueous solution containing carboxylic acids or polycarboxylic acids. The assembly of the components is carried out after the pre-treatment in the absence of liquid or gas flux.

A method for curing solder paste on a thermally fragile substrate is disclosed. An optically reflective layer and an optically absorptive layer are printed on a thermally fragile substrate. Multiple conductive traces are selectively deposited on the optically reflective layer and on the optically absorptive layer. Solder paste is then applied on selective locations that are corresponding to locations of the optically absorptive layer. After a component has been placed on the solder paste, the substrate is irradiated from one side with uniform pulsed light. The optically absorptive layer absorbs the pulsed light and becomes heated, and the heat is subsequently transferred to the solder paste and the component via thermal conduction in order to heat and melt the solder paste.

A flux unit includes a flux supply device configured to eject flux to a storage tray, an ejection port configured to eject the flux, and an ejection port moving device configured to move the ejection port in the radial direction of the storage tray. By this, the flux is ejected in a wide range in the radial direction of the storage tray. Also, the storage tray is rotated by a tray rotation device. Thus, the film thickness of the flux ejected in the wide range of the storage tray is adjusted by a squeegee all at once. Thus, the time required for adjusting the film thickness of the flux can be reduced.

Methods for refurbishing a circuitry device are disclosed. The methods described herein include applying a first flux to solder contacts connecting a first member of a circuitry device to a second member of the circuitry device; performing a first setting process on the circuitry device with the first flux; applying a second flux to the solder contacts of the circuitry device; performing a second setting process on the circuitry device; and reflowing the solder contacts.

The flux according to the present invention includes a fatty acid amide; a first solvent having a temperature, at which its mass measured by thermogravimetry at a nitrogen flow rate of 0.2 to 0.3 L per minute and a temperature increase rate of 10 C. per minute becomes zero, of from 180 C. to lower than 260 C.; and a second solvent having a temperature, at which its mass measured by thermogravimetry at a nitrogen flow rate of 0.2 to 0.3 L per minute and a temperature increase rate of 10 C. per minute becomes zero, of from 100 C. to lower than 220 C. The flux has a content of the first solvent that is lower than a content of the second solvent. The flux does not include reducing agents for reduction removal of surface oxide films of solder, and does not include activators for improving reducibility.

A method for curing solder paste on a thermally fragile substrate is disclosed. An optically reflective layer and an optically absorptive layer are printed on a thermally fragile substrate. Multiple conductive traces are selectively deposited on the optically reflective layer and on the optically absorptive layer. Solder paste is then applied on selective locations that are corresponding to locations of the optically absorptive layer. After a component has been placed on the solder paste, the substrate is irradiated from one side with uniform pulsed light. The optically absorptive layer absorbs the pulsed light and becomes heated, and the heat is subsequently transferred to the solder paste and the component via thermal conduction in order to heat and melt the solder paste.

There is provided the use of at least one ionic liquid as a soldering/brazing flux. There is also provided a method of soldering a metal comprising applying a solder/braze comprising a flux to a surface of the metal and heating said metal to a desired soldering/brazing temperature, wherein the soldering/brazing flux comprises one or more ionic liquids.

The object of the present invention is to provide a flux composition and a solder paste composition in which scattering of flux is suppressed.

A flux composition comprising an anti-scattering agent represented by formula (1) below,

##STR00001##

wherein Z is optionally substituted alkylene, R.sup.1 and R.sup.2 are each independently optionally substituted alkyl, optionally substituted aralkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted cycloalkyl, or optionally substituted heterocycloalkyl, R.sup.3 and R.sup.4 are each independently optionally substituted alkyl.

An ejector for jetting droplets of viscous media onto a substrate is disclosed. The ejector comprises a jetting nozzle having a nozzle space and a nozzle outlet, and an impacting device for impacting a volume of the viscous medium in the nozzle space such that droplets of viscous medium is jetted from the nozzle space through the nozzle outlet towards the substrate. The ejector also comprise a sensor arrangement arranged after the jetting nozzle in the jetting direction, wherein the sensor arrangement is adapted to detect a jetted droplet of viscous medium passing thereby.

A mounting substrate manufacturing method for soldering a terminal of an electronic component to a land 2 of a substrate 1 includes: a paste disposing step of disposing a solder paste on the land 2; a melting and solidifying step of melting and solidifying the solder paste, to form a precoated area 3 coated with solder, on the land 2; a breaking step of breaking a residue covering a surface of the precoated area 3 by pressing a tool 432, 442 against the precoated area 3; a flux disposing step of disposing a flux F on the precoated area 3; a component placement step of placing an electronic component on the substrate 1, with the terminal of the electronic component aligned with the precoated area 3; and a reflow step of heating the substrate 1 to melt the precoated area 3, to solder the terminal to the land 2. This can provide a mounting substrate manufacturing method that can reduce the occurrence of soldering defects.