A computer controlled apparatus is disclosed for performing a series of laser machining operations on a work piece in an environment comprised of a non-reactive gas with respect to the material of which the work piece is made. The computer controlled apparatus includes a machining chamber for receiving the work piece and means in the form of a pump for directing the non-reactive gas into the machining chamber at a controlled, selected rate. A laser beam is generated by a laser and is focused into a beam along a path to the work piece. An assembly is provided for selectively moving the machining chamber and its work piece therein through a sequence of steps, whereby the relative position between the work piece and the laser beam is changed such that a series of lasing operations and, in particular, welds may be effected on a sequence of selected sites of the work piece. A computer is programmed to control the rate at which the non-reactive gas is introduced into the machining chamber, as well as to the machining sites of the work piece, whereby the selectively moving assembly may be controlled to dispose the work piece to effect the series of welding operations.

Laser machining system

Apparatus for annealing semiconductor wafers includes a support for receiving the wafers and resistive heaters for heating the wafers by thermal conduction through the support or by convection. A high intensity arc lamp scans the heated wafers thereby raising the temperature sufficiently for heat treating. The process is simple, rapid, efficient, and does not create damaging thermal stresses in the wafers. The high temperature and short time treatment enables material properties unobtainable with conventional thermal processes.

Method and means for heat treating semiconductor material using high intensity CW lamps

A soldering method wherein a high-energy beam such as a laser beam is projected onto different lead terminal arrays of electronic components, the beam being projected in a scanning manner a plurality of times two-dimensionally and continuously is described. The invention further relates to a soldering apparatus comprising a mechanism for holding an electronic component by the tip thereof, a rotary drive mechanism (27) which turns the electronic component holding mechanism so that the position of the electronic component in the rotational direction is brought into agreement with a practical mounting position on the circuit board, holding unit-drive mechanisms (21, 22, 25) that move the electronic component-holding mechanism three-dimensionally, beam radiation mechanisms (41, 42) for irradiating the surface of the circuit board with high energy, beam radiation angle change mechanisms (53, 54) for changing the radiation angle of the high-energy beam emitted from the beam radiation mechanisms relative to the circuit board, and a beam scanning controller (47) which controls the beam radiation angle change mechanisms such that the high-energy beam scans a predetermined lead terminal array of the electronic components mounted on the circuit board a predetermined number of times. Using this apparatus, the soldering is effected under conditions where the temperature rise near the lead terminals and the temperature distribution are made uniform.

Method for soldering electronic component

The melting of solder in a reflow soldering operation is detected by examining the rate of change of the solder temperature whereby detecting a change in a surface reflectance characteristic of the solder which occurs upon melting.

Non-contact detection of liquefaction in meltable materials

An atmospheric pressure gaseous flux-assisted laser reflow soldering system provides a means of finely controlled soldering while eliminating post-soldering cleanup with environmentally damaging cleaning agents.

Atmospheric pressure gaseous-flux-assisted laser reflow soldering

Defective chips are removed from a substrate package. The package is cleaned. Replacement chips with solder bearing elements are replaced in the position(s) of the defective chip(s). Silicon chips are less damaged by heating with light wavelengths substantially shorter than infrared radiation, when the radiation is directed upon the upper chip surface and the lower chip surface carries circuitry and solder balls. Radiation is absorbed by the upper chip surface and converted there directly to heat, protecting the circuitry below. An argon-ion laser beam confined to a given chip is directed upon the upper surface of the chip to be soldered in place. A thin laser beam can be scanned under computer control across a chip to heat the areas of a chip above solder balls. Automatic temperature control of the chip can be provided by a heat detector or chip condition detector and a program controller in a feedback loop controlling laser power.

System for chip joining by short wavelength radiation

Le dispositif et le procede permettant de fixer une microplaquette (14) sur un module (12) a l'aide de billes de soudure (15) utilisent une chambre (10) remplie d'une atmosphere inerte percee d'une fenetre transparente (16) a travers laquelle on fait tomber sur la surface superieure de la microplaquette une radiation (31) d'un faisceau laser (29). The device and the method for fixing a chip (14) on a module (12) with the aid of solder balls (15) using a chamber (10) filled with an inert atmosphere pierced with a transparent window (16 ) through which is dropped on the top surface of the chip radiation (31) of a laser beam (29). Le laser est choisi de telle facon que, pour la longueur d'onde de la radiation, la surface de la microplaquette soit pratiquement opaque. The laser is selected such that for the wavelength of the radiation, the surface of the chip is substantially opaque. La longueur d'onde de la radiation se situe dans l'infra-rouge. The wavelength of the radiation is in the infrared. Son intensite est reglee a l'aide d'un detecteur (36) connecte a un systeme de regulation programme (38) agissant sur le laser (26). Its intensity is adjusted by means of a detector (36) connected to a programmed control system (38) acting on the laser (26). Ce dispositif permet d'eviter les dommages thermiques aux microplaquettes et peut etre utilise pour la fixation de microplaquettes remplacant des microplaquettes defectueuses. This device helps prevent thermal damage to the chips and can be used for attaching chips replacing defective chips.

Swie-In Tan

Papers

System for chip joining by short wavelength radiation

Method and device for fixing chips by energy beams

Device for packaging chip