A laser reflow method includes preparing a workpiece including a board and semiconductor chips each having one or more bumps formed on one surface thereof, the semiconductor chips being placed on the board with the bumps interposed therebetween. An inclination detection step captures an image of one semiconductor chip and detects an inclination of the semiconductor chip within the captured image. A laser beam irradiation step irradiates each semiconductor chip with a laser beam from another surface side opposite to the one surface to reflow the bumps formed within an irradiated range of the workpiece. A phase pattern displayed by a spatial light modulator is rotated in such a manner as to agree with the inclination of the detected semiconductor chip, to thereby rotate an irradiation range of the laser beam within an irradiated surface of the workpiece, before the semiconductor chips are irradiated with the laser beam.

A laser beam applying apparatus has a laser beam applying unit including a laser beam source for emitting the laser beam, a spatial light modulator for modulating the laser beam, according to phase patterns, and emitting the modulated laser beam, and a beam focusing assembly for focusing the laser beam modulated by the spatial light modulator and applying the focused laser beam to a plate-shaped workpiece. The laser beam applying apparatus also has a controller including a phase pattern storage section for storing a plurality of phase patterns representing respective different positions in a plane of the plate-shaped workpiece where the laser beam is applied when the phase patterns are displayed on the spatial light modulator, and a phase pattern control section for switching to predetermined phase patterns among the phase patterns stored in the phase pattern storage section as the phase patterns displayed on the spatial light modulator.

Bulk copper solder is highly desired as a solder compound because it is very electrically conductive and has a high melting point relative to other solders. A composition for a copper solder includes copper(II) oxide powder in the range of 37-53% by mass, silicon carbide (SiC) powder in the range of 8-14% by mass, and a flux in the range of 35%-53% by mass. Energy in the form of microwave energy can be applied to the copper solder to convert the Cu(II)O to Cu, for a Cu product conversion of >93%.

Bulk copper solder is highly desired as a solder compound because it is very electrically conductive and has a high melting point relative to other solders. A composition for a copper solder includes copper(II) oxide powder in the range of 37-53% by mass, silicon carbide (SiC) powder in the range of 8-14% by mass, and a flux in the range of 35%-53% by mass. Energy in the form of microwave energy can be applied to the copper solder to convert the Cu(II)O to Cu, for a Cu product conversion of >93%.

A method for providing a welded joint includes: providing a first metal sheet having a first melting point; providing a second metal sheet having a second melting point, the second melting point being lower than the first melting point; providing a weld material; and joining the first metal sheet and the second metal sheet together by means of the weld material, thus defining a first joining interface between the first metal sheet and the weld material and a second joining interface between the second metal sheet and the weld material. The joining includes heating the second metal sheet at the second joining interface to a temperature higher than the second melting point, but lower than the first melting point.

A method for butt laser welding two metal sheets includes providing a first metal sheet and a second metal sheet and butt welding the metal sheets along a direction of welding. The butt welding step includes simultaneously generating a first front keyhole in the first metal sheet, generating a second front keyhole in the second metal sheet, and generating a back keyhole in the first and second metal sheets. The first and second front laser beams and the back laser beam are configured in such a manner that at each moment in time, a solid phase region and/or a liquid phase region of the metal sheets remains between the first front keyhole and the back keyhole and between the second front keyhole and the back keyhole.

Disclosed are a laser bonding apparatus and a laser bonding method capable of bonding an electronic component to a three-dimensional structure having a regular or irregular shape in a curved portion such as an automobile tail lamp or a headlamp. The laser bonding apparatus and method for a three-dimensional structure may prevent misalignment and poor bonding of the electronic component with respect to the three-dimensional structure.

A method of making an amalgamation preform includes providing a particle-liquid mixture containing a plurality of types of solid particles and a liquid base metal. The plurality of types of solid particles at least includes reactive particles, reactable with the base metal, and non-reactive magnetic particles. A magnetic field is applied to the particle-liquid mixture to magnetically disperse the plurality of types of solid particles in the liquid base metal to form a particle-liquid dispersion without substantially inducing a reaction between the reactive particles and the liquid base metal. A playdough-like amalgamation preform is prepared based on the particle-liquid dispersion without solidifying the liquid base metal.

A bonding apparatus provided with a gas supplying unit for causing an inert gas to be sprayed from a spray aperture provided adjacent to a holding section of the bonding head. The spray aperture is provided so as to surround the holding section of the bonding head, in which a portion of the slits is a wide slit set to a higher jet flow rate of the inert gas than narrow slits of another portion, and the inert gas sprayed from the wide slit and the narrow slits forms an air curtain that surrounds the bonding portion between the semiconductor chip and the substrate. The inert gas sprayed from the wide slit forms a flow that passes between the semiconductor chip and the substrate.

A radiative heat collective bonder or gangbonder for packaging a semiconductor die stack is provided. The bonder generally includes a shroud positioned at least partially around the die stack and a radiative heat source positioned inward of the shroud and configured to emit a radiative heat flux in a direction away from the shroud. The bonder may further include a bondhead configured to contact the backside of the topmost die in the die stack and optionally include another bondhead configured to contact a substrate beneath the die stack. The radiative heat source may be configured to direct the radiative heat flux to at least a portion of the die stack to reduce a vertical temperature gradient in the die stack. One or both of the bondheads may be configured to concurrently direct a conductive heat flux into the die stack.