Embodiments of the present disclosure include method for sequentially mounting multiple semiconductor devices onto a substrate having a composite metal structure on both the semiconductor devices and the substrate for improved process tolerance and reduced device distances without thermal interference. The mounting process causes “selective” intermixing between the metal layers on the devices and the substrate and increases the melting point of the resulting alloy materials.

A method of furnace-less brazing of a substrate is provided. The method includes providing a substrate having a brazing region thereon; disposing braze precursor material containing a nickel powder, an aluminum powder, and a platinum group metal powder on the brazing region; and initiating an exothermic reaction of the braze precursor material such that the exothermic reaction produces a braze material that reaches a braze temperature above the liquidus temperature for the braze material. A braze precursor material is also provided.

A lead-free, antimony-free tin solder which is reliable at high temperatures and comprises from 3.5 to 4.5 wt.% of silver, 2.5 to 4 wt.% of bismuth, 0.3 to 0.8 wt.% of copper, 0.03 to 1 wt.% nickel, 0.005 to 1 wt.% germanium, and a balance of tin, together with any unavoidable impurities.

An inspection method includes applying a laser beam to a semiconductor chip to reflow a bump disposed on a surface of the semiconductor chip and included in an irradiation range of the workpiece, the laser beam being applied from an opposite surface of the semiconductor chip, capturing an image of the irradiation range with use of a thermal camera while the laser beam is applied to the semiconductor chip, and acquiring temperature information regarding the semiconductor chip from the captured image, storing in advance reference temperature information that represents temperature information obtained when the semiconductor chip and the board have normally been bonded to each other by the laser beam applied thereto, and determining whether or not the semiconductor chip and the board have normally been bonded to each other by the laser beam applied thereto, on the basis of the reference temperature information and the temperature information.

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.

A system for detecting machining errors for a laser machining system for machining a workpiece includes: a detection unit for detecting image data and height data of a machined workpiece surface; and a computing unit. The computing unit is designed to generate an input tensor based on the detected image data and height data and to determine an output tensor on the basis of the input tensor using a transfer function. The output tensor contains information on a machining error.

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.