Laser reflow method

Abstract

Improve the defect rate of laser reflow equipment. [Solution] The laser reflow apparatus of the present invention is characterized in that it comprises a laser pressure head module that pressurizes a bonding object consisting of a plurality of electronic components arranged on a substrate with a translucent pressure member and bonds the electronic components to the substrate by irradiating a laser beam through the pressure member, and a bonding object transport module that transports the bonding object carried in from one side of the laser pressure head module so that the bonding object can be subjected to reflow processing by the laser pressure head module and then transported to the other side.

Description

Technical Field

[0001] The present invention relates to a laser reflow apparatus and a laser reflow method. More specifically, the present invention relates to a laser reflow apparatus that simultaneously bonds and pressurizes electronic components by irradiating a laser while pressing a plurality of electronic components arranged on a substrate with a light-transmitting pressing member, and a laser reflow method using this apparatus.

Background Art

[0002] In industrial laser processing, an application field with micron (μm)-level accuracy is micro laser processing, which is widely used in the semiconductor industry, display industry, printed circuit board (PCB) industry, smartphone industry, etc. Memory chips used in all electronic devices have seen the development of technology to minimize the circuit interval in order to achieve integration density, performance, and ultra-high-speed communication speed. However, currently, the technology of simply reducing the circuit line width and the interval between line widths cannot reach the required level, and the memory chips have been improved to the level of vertical stacking. The stacking technology up to 128 layers has already been developed by TSMC, and the technology of stacking up to 72 layers has been applied to mass production by Samsung Electronics, SK Hynix, etc.

[0003] In addition, the research and development of technologies for mounting memory chips, microprocessor chips, graphic processor chips, wireless processor chips, sensor processor chips, etc. in one package is in full swing, and a considerable level of technology has already been put into practical use.

[0004] However, in the process of developing the aforementioned technology, since more electrons have to be involved in the signal processing process inside the ultra-high speed / ultra-high capacity semiconductor chip, the power consumption increases, and the problem of cooling treatment for heat generation is raised. Furthermore, in order to achieve the requirements of ultra-high speed signal processing and ultra-high frequency signal processing for more signals, a technical problem is raised that a large amount of electrical signals must be transmitted at ultra-high speed. Also, the number of signal lines has to increase, and the signal interface lines outside the semiconductor chip can no longer be processed in the one-dimensional lead wire method. Instead, the ball grid array (BGA) method (Fan-In BGA) or the method called Fan-in Wafer-Level-Package (FIWLP), which processes two-dimensionally at the bottom of the semiconductor chip, and the method of placing a signal layout redistribution layer under the ultra-fine BGA layer at the bottom of the chip and providing a secondary fine BGA layer below it (referred to as Fan-out BGA or Fan-out Wafer-Level-Package (F0WLP) or Fan-out Panel-Level-Package (FOPLP)) are applied.

[0005] In recent years, in the case of semiconductor chips, products with a thickness of 200 μm or less, including an EMC (Epoxy-Mold Compound) layer, have emerged. In order to attach such a micron-level ultra-hard thin semiconductor chip with a thickness of only a few hundred microns to an ultra-hard thin PCB, when applying a mass reflow (MR) process such as a thermal reflow oven technology, which is a conventional surface mounting technology (SMT) standard process, the semiconductor chip is exposed to an air temperature environment of 100 to 300 degrees (°C) for several hundred seconds. Therefore, various forms of soldering bonding failures may occur, such as chip-boundary warpage, PCB-boundary warpage, and random-bonding failure by thermal shock due to the difference in the coefficient of thermal expansion (CTE).

[0006] Therefore, recently, looking at the configuration of a laser reflow device that has been in the spotlight, in a method of bonding by irradiating a laser while pressing a bonding object (semiconductor chip or integrated circuit IC) with a laser head module for several seconds, bonding is performed by irradiating a laser in the form of a surface light source corresponding to the size of the semiconductor chip or integrated circuit (IC).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

[0008] Regarding such a laser reflow apparatus with a pressurization method, referring to Patent Document 1, while irradiating the back surface of a flip chip with a laser to heat the flip chip, a configuration of a flip chip heating and pressing module for pressing the flip chip onto a carrier substrate is disclosed.

[0009] However, the conventional laser reflow apparatus with a pressurization method disclosed in Patent Document 1 is separated into means for sucking a chip and moving it to a bonding position, and means for heating the back surface of the chip via a laser and pressing the chip onto a carrier substrate. Therefore, when bonding a plurality of semiconductor chips such as a semiconductor strip, since it is necessary to repeat the operation of irradiating a laser while pressing one semiconductor chip by the number of semiconductor chips, there is a problem that the working time increases.

[0010] On the other hand, referring to Patent Document 2, the laser reflow apparatus configuration described in the patent states that bonding processing is possible in a manner where the laser head conveys horizontally while the pressurization head presses a plurality of flip chips simultaneously and irradiates each flip chip with a laser one by one in sequence, or a single laser head irradiates a plurality of flip chips with a laser simultaneously.

[0011] However, according to the conventional laser reflow apparatus configuration of Patent Document 2 described above, since a single laser source is used, it is difficult to irradiate a uniform laser beam because the laser beam enters a plurality of flip chips arranged on a substrate at a plurality of angles. Therefore, it is expected that there will be many technical difficulties in uniformly performing reflow processing on a plurality of flip chips without defects.

[0012] Therefore, in the conventional laser reflow apparatuses disclosed in Patent Documents 1 and 2, while the overall working time is prolonged by sequentially pressurizing and irradiating a single flip chip one by one, even when irradiating a single laser beam onto a plurality of flip chips horizontally arranged in various substrate sizes for a plurality of processes, it is virtually difficult for uniform thermal energy to be transmitted to each flip chip. Therefore, in order to improve the bonding failure rate, a great deal of research and development and effort are required.

Summary of the Invention

Problems to be Solved by the Invention

[0013] Therefore, the present invention has been invented to solve the above problems. The present invention is configured such that the size of the pressurization and laser light projection area processed at one time can be easily adjusted by replacing the translucent pressurizing member so as to correspond to the sizes of various substrates. Therefore, an object of the present invention is to provide a laser pressurizing head module for a laser reflow apparatus that enables mass processing of a plurality of electronic components simultaneously by pressurization and laser reflow, while significantly improving the failure rate.

[0014] Another object of the present invention is to provide a laser pressurizing head module for a laser reflow apparatus that enables mass processing by irradiating a homogenized laser beam while simultaneously pressurizing a plurality of electronic components, and significantly improves the failure rate.

[0015] Furthermore, the present invention is configured such that the pressure can be set and adjusted independently for each edge portion of a plate-shaped holder unit to which a translucent pressurizing member is attached so as to correspond to the sizes of various substrates. Therefore, an object of the present invention is to provide a laser pressurizing head module for a laser reflow apparatus that enables mass processing by simultaneously pressurizing a plurality of electronic components and irradiating them with a laser beam, and performing a reflow process at one time, while significantly improving the failure rate.

[0016] The present invention is configured such that, regardless of the size of a bonding object on which a plurality of electronic components are seated on a substrate, a conveyor system can carry the bonding object into and out of a reflow processing area at one time, and the bonding object is gradually preheated to a predetermined temperature during conveyance for loading, so that a stable temperature rise up to the solder melting temperature is achieved without defects during laser reflow processing. Therefore, an object of the present invention is to provide a laser reflow apparatus that can perform a large amount of processing by simultaneously applying pressure to and irradiating a plurality of electronic components with a laser beam for reflow processing at one time, while significantly improving the defect rate.

[0017] The present invention is configured to immediately detect and compensate for temperature imbalance between the substrate and electronic components constituting the bonding object by precisely monitoring, with a plurality of temperature sensing sensors, the area where multi-laser beams are superposed and irradiated, thereby preventing bonding defects of specific electronic components. As a result, an object of the present invention is to provide a multi-laser module for a laser reflow apparatus that can perform a large amount of processing by simultaneously applying pressure to and irradiating a plurality of electronic components with a laser beam for reflow processing at one time, while significantly improving the bonding defect rate due to temperature imbalance.

[0018] The present invention adjusts the arrangement shape of the electronic components located below the translucent pressing member before pressing so that it is positioned at the center of the pressing surface of the translucent pressing member, so that the pressure transmitted to the electronic components during pressing by the translucent pressing member is evenly applied without being biased to one side. Therefore, an object of the present invention is to provide a laser reflow method for a laser reflow apparatus that can perform a large amount of processing by simultaneously applying pressure to and irradiating a plurality of electronic components with a laser beam for reflow processing at one time, while significantly improving the defect rate.

[0019] The present invention aims to provide a laser reflow method for a laser reflow apparatus that can perform reflow processing on a large number of electronic components at one time without bonding defects by sequentially controlling the processes of applying pressure and irradiating with a laser beam according to preset conditions for a plurality of electronic components, while significantly improving the defect rate.

Means for Solving the Problem

[0020] To achieve the above object, the present invention pressurizes a bonding object composed of a plurality of electronic components arranged on a substrate with a light-transmissive pressing member, and irradiates a laser beam through the pressing member to bond the electronic components to the substrate, a laser pressurizing head module; and a bonding object transfer module for transferring the bonding object to carry it in from one side of the laser pressurizing head module, pass it through the reflow process of the laser pressurizing head module, and carry it out to the other side.

[0021] Further, the laser pressurizing head module includes a holder unit for detachably attaching the light-transmissive pressing member; and a probe unit provided above the holder unit for inspecting the flatness of the pressing member mounted on the holder unit.

[0022] Further, the laser beam is a square laser beam homogenized by a beam shaper.

[0023] Further, the laser beam is superimposed and irradiated from two or more laser modules.

[0024] Further, the holder unit includes a lower plate plate having a through hole formed in the central portion so that the light-transmissive pressing member can be fitted, locked, and seated.

[0025] Further, the light-transmissive pressing member can be realized by any one of quartz, sapphire, fused silica glass, or diamond.

[0026] Further, the holder unit further includes a mask plate that is coupled to the upper part of the lower plate with a light-transmitting pressing member seated thereon, and has a vent hole formed in the central part thereof so that a laser beam passes therethrough.

[0027] Further, the through hole of the mask plate has a rectangular shape having an area equal to or larger than the pressing surface of the light-transmitting pressing member.

[0028] Further, the bottom surface of the lower plate has a shape in which the left and right edge portions are gently rounded.

[0029] Further, flatness adjusting means for adjusting the flatness of the light-transmitting pressing member by finely moving the edge of the lower plate in the vertical direction is further provided at each edge portion of the lower plate.

[0030] Further, the flatness adjusting means includes press brackets provided at each edge portion of the light-transmitting pressing member and the holder unit, and a vertical driving unit provided on one side of the press bracket and configured to convey the press bracket vertically in response to the driving of a motor.

[0031] Further, the vertical driving unit includes a ball screw and a motor for vertically conveying the press bracket, and a guide member for guiding the linear motion of the press bracket.

[0032] Further, the probe unit includes a probe for measuring flatness by piercing at least one or more points on the upper surface of the light-transmitting pressing member, a moving means for horizontally or vertically moving the probe, and a probe bracket for fixing the probe and the moving means.

[0033] Further, the probe probes by piercing four or more points including the edge points of the square on the upper surface of the light-transmitting pressing member.

[0034] Further, a protective film is further provided below the translucent pressing member to prevent gas (fumes) generated during laser bonding from adhering to the bottom surface of the translucent pressing member.

[0035] Further, the protective film can be realized by polytetrafluoroethylene resin (PTFE) or perfluoroalkoxy resin (PFA).

[0036] Further, the protective film is supplied by a reel-to-reel type protective film conveying unit that conveys the protective film wound in a roll shape while unwinding it to one side.

[0037] Further, the translucent pressing member includes a base material having a generally square panel shape as a whole, and a pressing surface that is formed to protrude from the bottom surface of the base material and is formed in a planar shape so that the bottom surface corresponds to a plurality of electronic components.

[0038] Further, between the base material and the pressing surface, at least one or more stepped portions that are recessed inward so that the area of the pressing surface is narrower than the area of the base material are further provided.

[0039] Further, a laser light blocking layer is formed on the side surface of the base material, the bottom surface, and the side surface of the stepped portion.

[0040] Further, the pressing surface is divided into two or more parts by grid grooves having a certain depth.

[0041] Further, a laser light blocking layer is further formed on the inner surface and the bottom surface of the grid grooves.

[0042] Further, the laser light blocking layer is composed of one or two or more composite layers among an Inconel coating layer, a diffuse reflection processing layer, or an HR (High Reflection) coating layer.

[0043] Further, the pressing surface has a square shape.

[0044] Furthermore, the edges on both sides of the pressing surface are chamfered or rounded.

[0045] In addition, an elastic damper layer is further provided on the pressing surface.

[0046] Also, the elastic damper layer can be realized with a silicon material.

[0047] The laser pressing head module includes a rectangular holder unit for detachably mounting a light-transmissive pressing member, and a pressure balancer that initializes the self-weights of the holder unit and the light-transmissive pressing member to the zero point by pressing the self-weights of the holder unit and the light-transmissive pressing member in the opposite direction while supporting the lower ends of the edges of the holder unit. and further includes a press unit that is provided in a non-contact state above each edge of the holder unit and presses each edge of the holder unit with a set pressure independently.

[0048] Also, the pressure balancer is composed of an air cylinder.

[0049] Also, the pressure balancer is composed of an elastic spring.

[0050] And the press unit is arranged separately, one for each edge, so as to press each edge of the holder unit with a set pressure independently.

[0051] Also, the press unit includes a press bracket that non-contactly grips each edge portion of the holder unit, and a pressing cylinder that is attached to the upper end of the press bracket and presses the holder unit downward by a set pressure for each.

[0052] Also, a precision pneumatic cylinder that can finely set and adjust the pressing force in kgf units is adopted for the pressing cylinder.

[0053] And, the pressure cylinder is further provided with a pressure sensing sensor for measuring the pressure during pressurization and constantly feeding back the pressure.

[0054] Also, above the holder unit, an ionizer unit for cleaning the upper surface of the light-transmissive pressurizing member from dust adsorption by static electricity is further provided.

[0055] Also, the bonding object transfer module includes an input conveyor on which a bonding object composed of a plurality of electronic components arranged on a substrate seats for being carried in, vacuum chucking means for vacuum-adsorbing and fixing the bonding object supplied from the input conveyor, and an output conveyor on which the bonding object after the laser reflow process seats for being carried out.

[0056] Furthermore, the input and output conveyors include a conveyor frame, a pair of wire track means provided on both sides at the upper part of the conveyor frame, and horizontal transfer means provided on one side of the conveyor frame for linearly moving the conveyor frame in the horizontal direction.

[0057] Also, on one side of the conveyor frame of the input and output conveyors, width adjustment means is further provided so that the width of the conveyor frame can be expanded or reduced to accommodate bonding objects of different sizes.

[0058] And, the conveyor frame of the input conveyor is further provided with a preheating stage for preheating the bonding object to a predetermined temperature.

[0059] Also, on one side of the vacuum chucking means, a vision unit for monitoring the presence or absence of normal loading of the bonding object is further provided.

[0060] Further, a picker unit for transporting each bonding object is further provided in the section between the input and output conveyors and the vacuum chucking means.

[0061] The picker unit further includes a vacuum suction pad on a flat plate and a vertical drive unit for vertically transporting the vacuum suction pad.

[0062] The vacuum chucking means further includes a porous suction plate for adsorbing and fixing the bonding object, and a horizontal transport means for reciprocally moving the porous suction plate and the heating block from the input area of the bonding object through the laser reflow processing area to the output area.

[0063] The porous suction plate is divided into a rectangular central suction plate for adsorbing the central portion of the bottom surface of the bonding object, and an edge suction plate disposed so as to surround the periphery of the central suction plate for adsorbing the bottom edge portion of the bonding object.

[0064] Further, suction holes for adsorbing the bottom edge portion of the bonding object are further formed in the edge suction plate.

[0065] The edge suction plate is made of an aluminum material.

[0066] A heating block is further provided below the porous suction plate.

[0067] The laser pressurization head module includes a multi-laser module that superimposes and irradiates a plurality of laser beams on the bonding object in a state of being divided from each other, and a temperature sensing sensor provided in the area between the multi-laser modules for sensing the temperatures of a plurality of points of the bonding object by irradiating the beam through a light-transmissive pressurizing member.

[0068] Further, the multi-laser module is composed of a pair of multi-laser modules facing each other.

[0069] Further, the temperature sensing sensor is composed of a single infrared temperature sensing sensor, and the single infrared temperature sensing sensor sequentially irradiates infrared rays on a plurality of points of the bonding object.

[0070] Further, the single infrared temperature sensing sensor sequentially irradiates infrared rays on a plurality of points in the periphery and the central portion within the region where a plurality of laser beams are superposed and irradiated.

[0071] Further, the temperature sensing sensor is composed of a plurality of infrared temperature sensing sensors, and the plurality of infrared temperature sensing sensors simultaneously irradiate infrared rays on a plurality of points of the bonding object.

[0072] In addition, the plurality of infrared temperature sensing sensors simultaneously irradiate infrared rays on a plurality of points in the periphery and the central portion within the region where a plurality of laser beams are superposed and irradiated.

[0073] Furthermore, the multi-laser module further includes a beam profiler for measuring the output and intensity of each laser beam.

[0074] Also, in a laser reflow method of a laser reflow apparatus for bonding electronic components to a substrate by pressing a bonding object having a plurality of electronic components arranged on a rectangular substrate with a light-transmissive pressing member and irradiating a laser beam through the pressing member, a) before the light-transmissive pressing member presses the bonding object, a step of the vision unit photographing the shape in which electronic components are arranged in a predetermined range located directly below the pressing surface of the light-transmissive pressing member; b) a step of determining that the shape in which the photographed electronic components are arranged is positioned corresponding to the pressing surface; c) when it is determined that the electronic components are positioned corresponding to the pressing surface, a step of moving the light-transmissive pressing member downward to press the bonding object and irradiating the bonding object with a laser beam through the light-transmissive pressing member; d) a step of stopping the irradiation of the laser beam and moving the light-transmissive pressing member upward to release the pressing state; and e) a step of horizontally transporting the light-transmissive pressing member above electronic components in a predetermined range to be reflowed next time.

[0075] Also, in step b), b1) a step of determining whether the electronic components are symmetrically positioned on the left and right with respect to the center line of the pressing surface of the light-transmissive pressing member when the shape in which the photographed electronic components are arranged is viewed from the side; and b2) when the shape in which the photographed electronic components are arranged is symmetrically positioned on the left and right with respect to the center line of the pressing surface of the light-transmissive pressing member, it is determined that they are positioned corresponding to the pressing surface, and when they are not positioned corresponding to the pressing surface, a step of adjusting the horizontal position of the light-transmissive pressing member so that the shape in which the electronic components are arranged is symmetrically positioned on the left and right with respect to the center line of the pressing surface of the light-transmissive pressing member.

[0076] In addition, the laser beam is superimposed and irradiated from two or more laser modules.

[0077] Furthermore, the laser modules are arranged symmetrically with respect to each other, and the laser beams have the same beam irradiation angle.

[0078] Also, laser beams are simultaneously irradiated from each of the laser modules.

[0079] In addition, laser beams are sequentially irradiated from each of the laser modules.

[0080] Also, before the step c), a step of preheating the bonding object at the lower part is further provided.

[0081] Also, in the step of preheating the bonding object at the lower part, the surface temperature of the bonding object is maintained below 200°C.

[0082] Also, in the step c), by irradiating the bonding object with a laser beam through the light-transmitting pressing member, the surface temperature of the bonding object is heated to 200°C or higher.

[0083] Also, in a laser reflow method of a laser reflow apparatus for bonding electronic components to a substrate by pressing a bonding object in which a plurality of electronic components are arranged on a rectangular substrate with a light-transmitting pressing member and irradiating the laser beam through the pressing member, a) a step of moving the pressing surface of the light-transmitting pressing member downward and bringing it into contact with the bonding object without applying a pressing force; b) a step of irradiating the bonding object with a laser beam through the light-transmitting pressing member; and c) a step of releasing the irradiation of the laser beam and moving the light-transmitting pressing member upward are provided.

[0084] Also, after the step a), a step of fixing the vertical movement of the light-transmitting pressing member is further provided.

[0085] Also, after the step a), a predetermined constant pressure is applied to the light-transmitting pressing member, and after the step b), a step of not fixing the vertical movement of the light-transmitting pressing member is further provided.

[0086] In addition, after the step a), the vertical movement of the light-transmitting pressing member is fixed, and after the step b), a step of applying a predetermined constant pressure to the light-transmitting pressing member is further provided.

[0087] Further, after the step a), the vertical movement of the light-transmitting pressing member is fixed, and after the step b), a stage where the vertical movement of the light-transmitting pressing member is not fixed is further provided.

[0088] Also, in the step b), laser beams are superimposed and irradiated from two or more laser modules.

[0089] Also, laser beams are simultaneously irradiated from each of the laser modules.

[0090] Also, laser beams are sequentially irradiated from each of the laser modules.

[0091] Further, a step of preheating the bonding object at the lower part before the step b) is further provided.

[0092] Also, in the step of preheating the bonding object at the lower part, the surface temperature of the bonding object is maintained below 200°C.

Advantages of the Invention

[0093] The present invention described above can simultaneously hold and press a plurality of electronic components and irradiate a uniform laser beam to transmit equal thermal energy to the plurality of electronic components, and has the effect of significantly improving productivity by a large-scale laser reflow process.

[0094] Also, since the mask plate and the light-transmitting pressing member can be replaced so as to be compatible with the size of the substrate and the arrangement shape of the electronic components, the defect rate is significantly reduced by uniformly performing the reflow process on all various substrates.

[0095] Also, the problem that the peripheral part of the substrate of the electronic component is thermally damaged by the laser beam leaking out at the edge of the Quartz constituting the pressing member, accelerating the deterioration of the substrate and the components, can be prevented, so that the defect rate is significantly reduced.

[0096] In addition, by configuring the pressure applied to each edge portion of the holder unit to which the light-transmitting pressing member is attached to be independently set and adjusted, the defect rate caused by insufficient pressure acting on a plurality of electronic components arranged on the substrate or by applying excessive pressure is significantly improved.

[0097] In addition, there is an effect that a bonding object with a certain area on which a plurality of electronic components are seated on the substrate can be stably carried in and out of the laser reflow processing area at once.

[0098] In addition, by monitoring the temperature imbalance in the overlapping irradiation area of the multi-laser beam and immediately detecting and repairing it, the bonding defect rate is significantly improved.

[0099] In addition, the position of the light-transmitting pressing member is adjusted so that the electronic component is not pressed down due to tilting to one side and the pressure is not evenly distributed, thereby significantly improving the defect rate caused by uneven pressure acting on a plurality of electronic components arranged on the substrate.

[0100] In addition, by precisely controlling the pressing by the light-transmitting pressing member and the laser beam irradiation by the laser module in sequence according to the set reference values, various bonding defects such as poor solder contact and overflow caused by insufficient pressing force or excessive pressure acting on a plurality of electronic components arranged on the substrate are significantly improved.

Brief Description of the Drawings

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MODE FOR CARRYING OUT THE INVENTION

[0131] The terms used in this specification are merely used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly has a different meaning. In this specification, terms such as "comprising", "having", or "providing" specify the existence of the features, numbers, steps, operations, components, parts, or combinations thereof described in this specification, and it should be understood that the existence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof is not precluded in advance.

[0132] Unless otherwise defined in this specification, all terms used in this specification, including technical and scientific terms, shall represent the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains.

[0133] Terms defined as in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted as having an ideal and overly formal meaning unless clearly defined in this specification.

[0134]

[0135] Hereinafter, with reference to the accompanying FIGS. 1 and 2, the laser reflow apparatus according to the present invention will be specifically described as follows.

[0136] FIG. 1 is an exemplary diagram showing the overall configuration of the laser reflow apparatus according to the present invention, and FIG. 2 is a block configuration diagram of FIG. 1.

[0137] As shown in FIGS. 1 and 2, the laser pressurizing head module 300 of the laser reflow apparatus according to the present invention includes at least one or more multi-laser modules 310 and 320 that irradiate a bonding object 11 being conveyed while being supported on a porous substance or a stage 111 having vacuum holes and having a structure capable of applying heat to the lower part thereof with a laser in a surface light source form, a light-transmitting pressurizing member 100 that is separately installed independently of the laser modules 310 and 320 and transmits a laser in a surface light source form, and a protective film 200 that protects the light-transmitting pressurizing member 100 from contamination.

[0138] First, the plurality of multi-laser modules 310 and 320 convert a laser generated by a laser oscillator and transmitted through an optical fiber into a surface light source and irradiate the bonding object 11. The laser modules 310 and 320 can be realized by including a beam shaper (see FIG. 5) that converts a laser in a spot form into a surface light source form, and an optical unit (see FIGS. 5 to 9) in which a plurality of lens modules are mounted in a lens barrel at appropriate intervals so that the surface light source emitted from the beam shaper irradiates an irradiation region of the bonding object (11).

[0139] The laser modules 310 and 320 can move up or down along the z-axis, move left and right along the x-axis, or move along the y-axis for alignment with the bonding object 11.

[0140] The laser pressurizing head module 300 of the laser reflow apparatus according to the present invention forms the light-transmissive pressurizing member 100 that pressurizes the bonding object 11 and the laser modules 310 and 320 that irradiate the bonding object 11 with a surface light source form of laser separately from each other. After moving the laser modules 310 and 320 to a plurality of irradiation positions of the bonding object 11 in a state where the bonding object 11 is pushed down by the light-transmissive pressurizing member 100 and then driving them, it is possible to shorten the tact time for one bonding object 11 and speed up the bonding operation for the entire plurality of bonding objects 11.

[0141] At this time, the light-transmissive pressurizing member 100 is transported to the working position or the standby position by a light-transmissive pressurizing member transport unit (not shown) in a predetermined form. As an example, the light-transmissive pressurizing member transport unit can lower or raise the light-transmissive pressurizing member 100, move it left and right, and then lower or raise it.

[0142] Although not shown in the drawings, the laser pressurizing head module 300 of the laser reflow apparatus according to the present invention further includes a control unit (not shown) that controls the operation of the light-transmissive pressurizing member transport unit using data input from a pressure sensing sensor (not shown) and a height sensor (not shown).

[0143] The pressure sensing sensor and the height sensor can be provided on the light-transmissive pressurizing member 100, the light-transmissive pressurizing member transport unit, and the stage 111 that supports the bonding object. For example, the control unit can receive data from the pressure sensing sensor and control the light-transmissive pressurizing member transport unit so that the pressure reaches the target value, and can also receive data from the height sensor and control the light-transmissive pressurizing member transport unit so that the height reaches the target value.

[0144] Further, a support part (not shown) supports the light-transmissive pressure member conveying part (not shown) movably. In one example, the support part can be implemented by a pair of gantries extending alongside the stage 111, and should be interpreted as including a configuration that supports the light-transmissive pressure member conveying part movably in the x-axis, y-axis, or z-axis.

[0145] The laser pressurizing head module 300 of the laser reflow apparatus according to the present invention can be realized by including one or more actuators that apply pressure to the light-transmissive pressure member 100, at least one pressure sensing sensor that senses the pressure exerted on the light-transmissive pressure member 100, and one or more height sensors that detect the height of the light-transmissive pressure member. The pressure sensing sensor can be realized by at least one load cell as an example, and the height sensor can be realized by a linear encoder.

[0146] When adjusting the pressure applied to the bonding object through the pressure sensing sensor in the case of a large area, it is possible to control so that the same pressure is transmitted to the bonding object through a plurality of actuators and a plurality of pressure sensing sensors, and also to confirm the height position value at the moment when the bonding object is bonded through one or more height sensors, or to provide technical data for finding a more accurate bonding height value, and to execute a function that can control the accurate height when performing a process that must maintain a certain height interval.

[0147] Further, the light-transmissive pressure member 100 can be realized as a base material that transmits the laser output from the laser modules 310 and 320. The base material of the light-transmissive pressure member 100 can be realized by any beam-transmissive material.

[0148] The base material of the light-transmitting pressure member 100 can be realized by, for example, any one of quartz, sapphire, fused silica glass, or diamond. However, the physical properties of the light-transmitting pressure member realized with a quartz material are different from those of the light-transmitting pressure member realized with sapphire. For example, when irradiating with a 980 nm laser, the transmittance of the light-transmitting pressure member realized with a quartz material is 85% - 99%, and the temperature measured on the bonding object is 100°C. On the other hand, the transmittance of the light-transmitting pressure member realized with sapphire is 80% - 90%, and the temperature measured on the bonding object is 60°C.

[0149] In other words, from the viewpoints of light transmittance and heat loss required for bonding, quartz exhibits better performance than sapphire. However, when the present applicant inventor repeatedly tested the light-transmitting pressure member 100 while developing a laser reflow apparatus, it was found that the light-transmitting pressure member 100 realized with a quartz material had problems such as cracks occurring or combustion occurring on the bottom surface during laser bonding, resulting in poor bonding quality. This was analyzed to be that the gas generated during laser bonding adhered to the bottom surface of the light-transmitting pressure member 100, and the laser heat source concentrated on the part where the gas adhered, increasing the thermal stress.

[0150] To prevent damage to the light-transmitting pressure member 100 realized with a quartz material and improve durability, a thin film coating layer can be formed on the bottom surface of the light-transmitting pressure member realized with a quartz material. The thin film coating layer formed on the bottom surface of the light-transmitting pressure member 100 can be implemented with a dielectric coating, which is a normal optical coating, or a SiC coating, or a metal material coating.

[0151] As shown in FIG. 1, the laser pressurization head module 300 of the laser reflow apparatus according to the present invention includes, below the translucent pressurization member 100, a protective film 200 that prevents the gas (fumes) generated during laser bonding from adhering to the bottom surface of the translucent pressurization member 100, and a protective film conveyance unit 210 that conveys the protective film 200.

[0152] The protective film conveyance unit 210 can be realized by a reel-to-reel method that conveys the protective film 200 wound in a roll shape to one side while unwinding it. The protective film 200 is an example, and it is preferably realized with a material having a maximum use temperature of 300 degrees Celsius or higher and a continuous maximum use temperature of 260 degrees Celsius or higher, and excellent heat resistance. For example, the protective film 200 can be made of polytetrafluoroethylene resin (usually also called Teflon resin; polytetrafluoroethylene, PTFE) or perfluoroalkoxy resin. Perfluoroalkoxy resin (Per Fluroro Alkylvinvether copolymer; PFA) is a product that improves the heat resistance of fluorinated ethylene propylene resin, and its continuous maximum use temperature is recorded at the same 260 degrees Celsius as that of polytetrafluoroethylene resin, and it is a high-functional resin.

[0153]

[0154] FIG. 3 is a conceptual diagram of a single laser module according to an embodiment of the laser reflow apparatus according to the present invention, and FIG. 4 is a conceptual diagram of a multi-laser module according to another embodiment of the laser reflow apparatus according to the present invention.

[0155] Referring to FIG. 3, the present invention includes a single laser module 310 according to an embodiment, and thereby irradiates a single laser beam onto a PCB (Printed Circuit Board) substrate. According to an embodiment, the PCB substrate can be a flexible circuit board (Flexible PCB).

[0156] At this time, referring to FIG. 3, the laser beam irradiated by the first laser module 310 is irradiated onto the substrate in a state where it is deformed into a square beam shape with the intensity of the laser beam homogenized.

[0157] On the other hand, referring to FIG. 4, a multi-laser module according to another embodiment of the present invention is composed of, for example, a first laser module 310 and a second laser module 320. At the position where the electronic component of the bonding object 11 is attached, a superimposed laser beam homogenized by irradiating in a state where the first and second laser modules are overlapped is irradiated.

[0158] In FIG. 4, it is shown that the first laser beam is square and the second laser beam is circular, but both laser beams may be square. Also, the first and second laser beams may be irradiated simultaneously, or the second laser beam may be sequentially irradiated after preheating the bonding object 11 with the first laser beam.

[0159]

[0160] FIG. 5 is a configuration diagram of a multi-laser module according to another embodiment of the laser reflow apparatus according to the present invention.

[0161] In FIG. 5, each laser module 310, 320,... 330 includes a laser oscillator 311, 321, 331 provided with a cooling device 316, 326, 336, a beam shaper 312, 322, 332, an optical lens module 313, 323, 333, a drive device 314, 324, 334, a control device 315, 325, 335, and a power supply unit 317, 327, 337.

[0162] Hereinafter, except when necessary, in order to avoid redundant description, among the laser modules having the same configuration, the description will be centered on the first laser module 310.

[0163] The laser oscillator 311 generates a laser beam having a wavelength and output power within a predetermined range. As an example, the laser oscillator can be a diode laser (LD) having a wavelength of 750 nm to 1200 nm, or 1400 nm to 1600 nm, or 1800 nm to 2200 nm, or 2500 nm to 3200 nm, or a rare-earth-doped fiber laser, or a rare-earth-doped crystal laser. Alternatively, it can be implemented including a medium for emitting Alexandrite laser light having a wavelength of 755 nm, or a medium for emitting Nd:YAG laser light having a wavelength of 1064 nm or 1320 nm.

[0164] The beam shaper 312 converts a laser in the form of a spot generated by the laser oscillator and passing through the optical fiber into the form of an area beam having a flat top. The beam shaper 312 can include a square light pipe, a diffractive optical element (DOE), or a micro-lens array (MLA).

[0165] The optical lens module 313 adjusts the shape and size of the laser beam converted into the area beam form by the beam shaper and irradiates the electronic components mounted on the PCB substrate or the irradiation region. The optical lens module combines a plurality of lenses to form an optical system, and the specific configuration of such an optical system will be specifically described later with reference to FIGS. 6 to 9.

[0166] The driving device 314 moves the distance and position of the laser module with respect to the irradiation surface, and the control device 315 controls the driving device 314 to adjust the beam shape, beam area size, beam clarity, and beam irradiation angle when the laser beam reaches the irradiation surface. In addition to the driving device 314, the control device 315 can also integrally control the operations of each part of the laser module 310.

[0167] On the other hand, the laser output adjustment unit 370 controls the amount of power supplied to each laser module from the power supply units 317, 327, and 337 corresponding to the laser modules 310, 320, and 330 according to a program received via the user interface or a preset program. The laser output adjustment unit 370 receives component-by-component, region-by-region, or overall reflow state information on the irradiation surface from one or more camera modules 350 and controls each power supply unit 317, 327, 337 based on this information. Alternatively, it is also possible to transmit the control information from the laser output adjustment unit 370 to the control devices 315, 325, and 335 of the laser modules 310, 320, and 330, and for each control device 315, 325, and 335 to provide a feedback signal for controlling the corresponding power supply unit 317. Also, different from FIG. 6, it is possible to distribute power to each laser module via one power supply unit, and in this case, the laser output adjustment unit 370 must control the power supply unit.

[0168] When implementing the laser superposition mode, the laser output adjustment unit 370 controls each laser module and the power supply units 317, 327, and 337 so that the laser beams from each laser module 310, 320, and 330 have the required beam shape, beam area size, beam clarity, and beam irradiation angle. The laser superposition mode is applicable not only when preheating the area around the debonding target position using the first laser module 310 and further heating a narrower reflow target area using the second laser module 320, but also when appropriately distributing an additional heating function among the first, second, and third laser modules 310, 320,... 330 from the preheating function to control each laser module to have the required temperature profile.

[0169] On the other hand, when distributing one laser light source and inputting it to each laser module, the laser output adjustment unit 370 can be provided with a function of simultaneously adjusting the output and phase of each distributed laser beam. In such a case, the phase can be controlled so as to induce destructive interference between the laser beams, significantly improving the beam flatness, thereby further improving the energy efficiency.

[0170] On the other hand, when realizing the multi-position simultaneous processing mode, the laser output adjustment unit 370 controls one or more of the beam shape, beam area size, beam sharpness, beam irradiation angle, and beam wavelength of each laser beam so that part or all of the laser beams from each laser module are different. Also in that case, when distributing one laser light source and inputting it to each laser module, the laser output adjustment unit 370 may be provided with a function of simultaneously adjusting the output and phase of each distributed laser beam.

[0171] With this function, by adjusting the size and output of the laser beam, it is possible to perform or remove the bonding between the electronic component and the substrate within the irradiation surface. In particular, when removing a damaged electronic component on the substrate, as the area of the laser beam is minimized to the corresponding electronic component region, the heat from the laser beam applied to other adjacent normal electronic components existing on the substrate can be minimized. Therefore, it is possible to remove only the damaged electronic component to be removed.

[0172] On the one hand, when a laser beam having different wavelengths is emitted for each of a plurality of laser modules, the laser modules are well absorbed by a plurality of material layers (e.g., EMC layer, silicon layer, solder layer) included in the electronic component. It can be composed of individual laser modules having wavelengths. Therefore, the laser debonding apparatus according to the present invention selectively raises the temperature of the electronic component and the temperature of an intermediate bonding material such as solder, which is a connection material between the printed circuit board and the electronic component electrode, to be different, and performs an optimized bonding (Attathing or Bonding) or (Detaching or Debonding) process. Specifically, all the energy of each laser beam is absorbed by the solder layer through both the EMC mold layer and the silicon layer of the electronic component, or the laser beam does not pass through the EMC mold layer and heats the surface of the electronic component, and heat is conducted to the bonding portion below the electronic component.

[0173] On the other hand, using the above functions, after a certain area of the substrate including the reflow target electronic component area and its periphery is preheated to a predetermined preheating temperature by at least one first laser beam, the temperature of the reflow target electronic component area is selectively heated to the reflow temperature at which the solder melts by at least one second laser beam. By utilizing such a selective heating effect, the present invention can also be used as, for example, a rework apparatus for efficiently removing an electronic component from a substrate.

[0174]

[0175] FIGS. 6 to 9 are configuration diagrams of a laser optical system applicable to a single laser beam or a multi-laser module of the laser reflow apparatus of the present invention.

[0176] FIG. 6 shows an optical system with the simplest structure applicable to the present invention. When the laser beam emitted from the beam transmission optical fiber 410 is focused through the convex lens 420 and enters the beam shaper 430, the beam shaper 430 converts the spot-shaped laser beam into a flat-top surface light source A1. The square laser beam A1 output from the beam shaper 430 is expanded to a desired size through the concave lens 440 and irradiates the imaging surface S with the expanded surface light source A2.

[0177]

[0178] FIG. 7 is a configuration diagram of a laser optical system according to another embodiment of the present invention.

[0179] The surface light source B1 from the beam shaper 430 is expanded to a predetermined size through the concave lens 440 and becomes a surface light source B2 that irradiates the first imaging surface S1. When it is desired to further expand this surface light source B2 for use, the boundary of the edge of the surface light source B2 may become less distinct due to additional expansion. Therefore, in order to obtain irradiation light with a clear edge even on the second imaging surface S2 for the final irradiation surface, a mask 450 is provided on the first imaging surface S1 to trim the edge.

[0180] The surface light source that has passed through the mask 450 is adjusted to be reduced (or expanded) to a desired size while passing through the zoom lens module 460 composed of a combination of one or more convex lenses and concave lenses, and forms a square irradiation light B3 on the second imaging surface S2 where electronic components are arranged.

[0181]

[0182] It is a configuration diagram of a laser optical system according to another embodiment of the present invention.

[0183] After the square surface light source C1 from the beam shaper 430 is enlarged to a predetermined size through the concave lens 440, it is enlarged (or reduced) C2, for example, in the x-axis direction while passing through at least a pair of cylindrical lenses 470, and is reduced (or enlarged), for example, in the y-axis direction while passing through at least a pair of cylindrical lenses 480 again, and is converted into a rectangular surface light source C3.

[0184] Here, the cylindrical lens is in a form obtained by cutting a cylindrical shape in the longitudinal direction, and has a function of enlarging or reducing the laser beam according to the form in which each lens is arranged in the vertical direction, and adjusts the laser beam in the x-axis or y-axis direction according to the form in which the lenses on the surface where the cylindrical lens is arranged are arranged in the x and y-axis directions.

[0185] Subsequently, the surface light source C3 is enlarged (or reduced) to a desired size while passing through the zoom lens module 460 composed of a combination of one or more convex lenses and concave lenses, and forms a rectangular irradiation light C4 on the second imaging surface S2 where the electronic components are arranged.

[0186]

[0187] It is a configuration diagram of a laser optical system according to another embodiment of the present invention.

[0188] It can be understood that the optical system of FIG. 9 is a configuration in which a mask is applied to the optical system of FIG. 8 to trim the edge of the laser beam, and a final surface light source D5 having a sharper edge can be obtained compared to the case of FIG. 8.

[0189]

[0190] FIG. 10 is a perspective view of a main part schematically showing the holder unit configuration of the laser pressurizing head module of the present invention.

[0191] Referring to FIG. 10, the holder unit 500 according to the present invention is divided into a lower plate 510 into which the lower part of the flat plate-shaped light-transmitting pressure member 100 is fitted and seated, and a mask plate 520 that fits and engages with the upper part of the light-transmitting pressure member 100.

[0192] Further, square through holes 510a and 520a are formed in the central portions of the lower plate 510 and the mask plate 520, respectively. Since the light-transmitting pressure member 100 is fitted and seated on the lower plate 510, at this time, it can be understood that the bottom surface 102 of the pressure member 100 is exposed downward through the through hole 510a of the lower plate 510.

[0193] On the other hand, in the above state, when the mask plate 520 is fitted and coupled to the upper surface of the light-transmitting pressure member 100, the mounting is completed with the central portion of the upper surface of the light-transmitting pressure member 100 exposed upward through the through hole 520a of the mask plate 520.

[0194]

[0195] FIG. 11 is a cross-sectional view of a main part schematically showing the configuration and operating state of the holder unit of the laser pressure head module of the present invention.

[0196] Referring to FIG. 11, when the light-transmitting pressure member is irradiated with laser light by the multi-beam laser modules 310 and 320 located above in a state where it is mounted between the lower plate and the mask plate, it is understandable that the laser beam is transmitted downward through the through hole 520a of the mask plate 520 and the light-transmitting pressure member 100.

[0197] At this time, the left and right side edges of the bottom surface of the lower plate 510 have a gently rounded shape. This is because when the protective film 200 located below the light-transmitting pressure member is pushed down while the light-transmitting pressure member 100 moves downward, the rounded edges of the lower plate 510 prevent the protective film 200 from being torn or damaged.

[0198] Further, as described above, the protective film 200 is pulled and wound by the protective film conveying units 210 disposed on both the left and right sides of the protective film 200. At this time, since the left and right edge portions of the bottom surface of the lower plate 510 are gently rounded, the protective film 200 can be fed without being damaged by the edges.

[0199] As described above, the light-transmissive pressing member 100 is irradiated with laser beams by the multi-laser modules 310 and 320 positioned above while pressing a plurality of electronic components disposed on the substrate, which is the bonding object 11, at a constant depth simultaneously. Thereby, the laser reflow process proceeds while the solder located below the electronic components of the bonding object 11 is melted by the laser beams.

[0200] As a result, the laser beams overlap each other to form a homogenized laser beam, and it can be understood that uniform thermal energy is transmitted through the through holes 520a of the mask plate 520 and the through holes 520a of the light-transmissive pressing member 100 and the lower plate 510 to the solder located below the electronic components of the bonding object (11).

[0201] At this time, when the overlapping laser beams are irradiated on the substrate portion around the electronic components, the peripheral substrate portion may be damaged by the thermal energy of the laser beams. Therefore, it is necessary to limit the irradiation only to the electronic components of the bonding object 11. For this purpose, in order to accurately perform the pressing and laser reflow processes only on the electronic components of the bonding object 11, it is desirable to design the area of the square through hole 520a of the mask plate 520 and the area of the pressing surface 102 of the light-transmissive pressing member 100 in consideration of the laser beam transmission path, overlapping area, etc.

[0202]

[0203] FIG. 12 is a perspective view of a main part schematically showing the configuration and operating state of the probe unit of the laser pressing head module of the present invention.

[0204] The main feature of the present invention is that the mask plate 520 and the translucent pressing member 100 are configured to be replaceable so as to accommodate various substrate sizes. Therefore, depending on whether to process substrates of different sizes or according to the shape and area where electronic components are arranged on the substrate, the translucent pressing member 100 and the mask plate 520 can be configured to be replaceable with different ones. In this case, the operator will select and replace an appropriate size from the pre-prepared translucent pressing member 100 and mask plate 520 having pressing surfaces of various different sizes as needed, and then measure the flatness by piercing and probing the edge portion of the upper surface of the translucent pressing member 100 through the bar probe unit 600 shown in FIG. 12.

[0205] The probe unit 600 is composed of a needle-shaped probe 610, a probe transport unit 620 for horizontally or vertically transporting the probe, and a probe bracket 630 for supporting the probe and the transport unit.

[0206] Therefore, in order to process substrates of different sizes, when the operator replaces the translucent pressing member 100 and the mask plate 520 of other sizes, the probe 610 is transported in the horizontal or vertical direction, and as an example, by sequentially piercing and probing at least 4 points (indicated by X) on the edge portion of the upper surface of the translucent pressing member (100), the flatness of the translucent pressing member 100 can be measured.

[0207]

[0208] FIG. 13 is a side view schematically showing the vertical transport unit configuration and operating state of a laser pressing head module according to an embodiment of the present invention.

[0209] Next, referring to FIG. 13, the configuration and operating state of the vertical transport unit of the laser pressing head module are as follows.

[0210] According to one embodiment of the vertical transfer unit configuration, there are provided press brackets 720 provided at four edge portions of each of the light-transmissive pressure member 100 and the holder unit 500, a pressure cylinder 730 provided above the press brackets, and a vertical drive unit that applies a driving force to the press brackets 720 in the vertical direction. That is, as an example, it can be composed of a ball screw 750, a motor 760, and a guide member 770 for guiding the linear motion of the press bracket 720.

[0211] Therefore, before the bonding object 11 composed of the substrate and the electronic component is loaded below the light-transmissive pressure member 100, the light-transmissive pressure member 100 and the holder unit 500 are transported upward by driving the motor 760 of the vertical transfer unit. After the bonding object 11 is loaded, the light-transmissive pressure member 100 and the holder unit 500 are transported downward again by driving the motor 760 and wait for pressurization. Then, by the operation of the pressure cylinder 730, the light-transmissive pressure member 100 presses the bonding object 11 vacuum-adsorbed on the electrostatic chuck 940.

[0212] On the other hand, since a heating block 942 for preheating the bonding object 11 to a constant temperature is provided below the electrostatic chuck 940, while the bonding object 11 is seated on the electrostatic chuck 940 and being transported for laser reflow processing, the bonding object 11 is continuously preheated. For example, the temperature for preheating the bonding object 11 can be set to less than 200°C, and it is desirable to set the temperature to such an extent that no thermal damage is caused to the substrate or the like by the preheating.

[0213] On the other hand, as shown in FIG. 12, when the probe unit 600 measures the flatness of the light-transmissive pressure member 100 and determines that the light-transmissive pressure member 100 is inclined to either side, that is, when it is not flat, the vertical transfer unit is finely driven to transport the holder unit 500 upward or downward, thereby adjusting the flatness of the light-transmissive pressure member 100.

[0214] More specifically, as a result of measuring the flatness of the light-transmissive pressing member 100 by the probe unit 600, when it is determined that one of the four edges on the upper surface of the light-transmissive pressing member 100 is inclined to one side with respect to the other edges and is located at a low point, as an example, the motor 760 of the edge portion located at the lower point operates to finely lift the edge of the holder unit 500 upward, thereby adjusting the overall flatness of the light-transmissive pressing member 100.

[0215] At this time, for the motor 760, for example, by installing an absolute encoder, the absolute position value of each edge portion of the holder unit 500 can always be maintained regardless of the power state, and it is desirable to automate the flatness adjustment process of the above-described light-transmissive pressing member (100) according to the control unit setting.

[0216]

[0217] FIG. 14 is a perspective view of a main part schematically showing the vertical transfer unit configuration and operating state of a laser pressing head module according to another embodiment of the present invention, and FIG. 15 is a side cross-sectional view of the main part of FIG. 14.

[0218] Hereinafter, referring to the above drawings, the detailed configuration of the laser pressing head module of the present invention and the operating relationship by pressing and laser beam irradiation will be described in more detail with reference to one embodiment as follows.

[0219] Referring to the drawings, the pressing head of the present invention includes a light-transmissive pressing member 100 for transmitting a laser beam irradiated from laser sources 310 and 320 while pressing an electronic component, which is a bonding object 11. At this time, the light-transmissive pressing member 100 is mounted in a state of being replaceably fitted into a through hole formed in the central portion of the plate-shaped holder unit 500.

[0220] The holder unit 500 can be formed to have a circular or polygonal shape (see FIGS. 16a and 16b). Hereinafter, in FIGS. 14 and 15, it will be described assuming that it has an octagonal shape.

[0221] According to an embodiment of the present invention, press units 700 are respectively condensed at the thin points P1, P2, and P3 around the grid lines of the octagonal holder unit 500. When the points where the press units are condensed are connected by an imaginary line L at that time, a triangle is formed.

[0222] At this time, the virtual triangle connecting the detailed points of the holder unit 500 can form an equilateral triangle, and it is desirable that the centroid G of the virtual triangle coincides with the centroid G of the light-transmitting pressing member 100.

[0223] The reason for designing the three-axis coupling points P1, P2, and P3 around the edge of the holder unit 500 is that when two press units are shrink-coupled to connect the axis coupling points P1, P2, and P3, it is stable. Since a triangular structure cannot be formed (that is, when connecting two points, a line segment is formed and an area cannot be formed), that is, while minimizing the number of condensation points that require flatness control, in order to form a stable axis coupling point of the virtual triangle, three axis coupling points P1, P2, and P3 are accurately and symmetrically configured on the holder unit 500.

[0224]

[0225] On the other hand, referring to FIG. 15, the press unit 700 includes a press bracket 720 having a certain height and shape, a pressure cylinder 730 that is mounted on the upper end of the press bracket and presses the holder unit 500 downward by a set pressure, and a bearing joint 780 whose one end is coupled to the cylinder rod 731 of the pressure cylinder 730 and whose other end is rotatably coupled to one of the detailed axis coupling points P1, P2, and P3 of the holder unit 500. At this time, the pressure cylinder can employ a precision pneumatic cylinder (hereinafter, a positive hole cylinder) that can finely set and adjust the pressing force in kgf units.

[0226] At this time, a pressure sensing sensor 740 is further provided at the end of the cylinder rod 731 of each pressurizing cylinder 730.

[0227] The pressure sensing sensor 740 can be realized as a load cell as an example. When the cylinder rod of each pressurizing cylinder 730 is pulled out to pressurize each shaft coupling point of the holder unit 500, it constantly measures it, checks whether a pressure equal to or higher than the appropriate pressure is applied, and plays a role of feeding this back to a control unit (not shown).

[0228] On the other hand, a joint fastening part 510 is further provided at each of the three shaft engagement points of the holder unit 500, and each joint fastening part 510 is rotatably coupled to a bearing joint 780 by a pivot hinge.

[0229] Therefore, depending on whether the cylinder rod 731 of the pressurizing cylinder 730 is retracted or pulled out, the bearing joint 780 pivotally hinged to the end of the cylinder rod 731 also moves vertically together, and thereby the joint fastening part 510 and the holder unit 500 rotatably coupled to the bearing joint 780 also move together.

[0230] Therefore, by adjusting the pulling-out lengths of the cylinder rods 731 of the respective pressurizing cylinders 730 to be different, the holder unit 500 can be tilt-driven, and thereby the pressing force can also be precisely adjusted by adjusting the contact height of the holder unit 500.

[0231] Also, the end of the joint fastening part 510 is locked by a stopper 790 provided at the lower end of the press bracket 720 and is in a seated state. Thereby, the self-weight of the holder unit 500 acting downward is offset by crossing the stopper 790, and it plays a role of maintaining flatness when vertically transporting the holder unit 500.

[0232] On one side of the press bracket 720, a vertical conveyance unit for moving the press bracket up and down in the vertical direction is further provided.

[0233] According to an embodiment of the vertical conveyance unit configuration below, it can be composed of press brackets 720 respectively provided at three shaft engagement points of the light-transmitting pressure member 100 and the holder unit 500, a pressure cylinder 730 provided at the upper part of the press bracket, a ball screw 750 and a motor 760 for driving the press bracket 720 in the vertical direction, and a guide member 770 for guiding the linear motion of the press bracket 720.

[0234] With the above configuration, when the holder unit 500 moves downward, the light-transmitting pressure member 100 mounted on the holder unit 500 also moves downward together, and it is understandable that the electronic component 11 located below it is pushed down and pressurized.

[0235] Also, since the flatness of the holder unit 500 may be distorted by vibrations generated during the progress of the reflow process or vibrations during the replacement of the light-transmitting pressure member 100, it is desirable to set the flatness by initializing to the zero point after replacing the light-transmitting pressure member 100 at a certain cycle.

[0236]

[0237] FIG. 16a is a partial plan view showing the holder unit of the laser pressure head module according to the present invention formed in an octagon according to an embodiment.

[0238] First, the shape of the holder unit according to the present invention may be polygonal, and may basically be a triangular shape connecting three shaft coupling points P1, P2, and P3. More specifically, for geometric symmetry, it can be formed into an equilateral triangle by making the lengths of the virtual lines connecting each of the three shaft coupling points P1, P2, and P3 to the central centroid G equal.

[0239] Also, in Fig. 16a, since a square translucent pressing member must be seated and accommodated inside the polygonal holder unit, an embodiment is shown in which the shape of the holder unit is octagonal so as to provide a larger area than the translucent pressing member and thus sufficiently accommodate the square translucent pressing member.

[0240] Therefore, the holder unit of the present invention is not limited to the octagonal shape shown in Fig. 16a, and can be realized in various polygonal shapes such as a triangle, a quadrilateral, or an octagon that can planar ly provide a virtual triangle connecting three shaft coupling points P1, P2, and P3.

[0241]

[0242] On the other hand, Fig. 16b is a plan view of a main part of the holder unit of the laser pressing head module according to the present invention formed in a circular shape according to another embodiment.

[0243] Also, the shape of the holder unit of the present invention may be polygonal or may be formed in a circular shape according to other embodiments.

[0244] Therefore, even if the holder unit is formed in a circular shape as shown in Fig. 16(b), the lengths of the virtual lines connecting each of the three shaft coupling points P1, P2, and P3 around the edge of the holder unit to the central centroid G are equal ly formed, so that the holder unit becomes geometrically symmetric, and each shaft coupling point can be precisely pressed and controlled while maintaining a high flatness using only the minimum three shaft coupling points P1, P2, and P3.

[0245]

[0246] Therefore, as described above, the pressing head of the present invention irradiates the translucent laser beam while simultaneously pressing and pressurizing a plurality of electronic components 11 using a translucent pressing member 100 having a certain area, so that reflow processing can be performed at once. Compared with the conventional method of raising a small translucent pressing member for each electronic component and pressurizing it by its own weight, the accuracy and productivity are significantly improved.

[0247] In addition, the pressurizing cylinder 730 adopts a positive hole cylinder that can precisely adjust the pressure in Kgf units, so that the pressure can be precisely adjusted. Accordingly, the operator can adjust the set pressure of the pressurizing cylinder 730 differently according to various variable factors such as the bending state of the FPCB substrate, and thus the pressure balance applied to the electronic component 11 disposed below the large-area light-transmissive pressurizing member 100 of the present invention can be easily adjusted compared with the prior art.

[0248] On the other hand, when a pressure higher than the set pressure is applied, different from the pressure set for each of the pressurizing cylinders 730, at this time, the pressure sensor 740 coupled to the end of the cylinder rod 731 of the pressurizing cylinder 730 senses this and feeds it back to a control unit (not shown).

[0249] Therefore, when a pressure above a certain level is sensed, the control unit performs an auto balance process of adjusting to the set pressure value, or generates an alarm so that the operator can easily manually adjust the set pressure of each of the pressurizing cylinders 730 as needed.

[0250]

[0251] Also, although not shown in FIGS. 14 to 16a and 16b, the holder unit 500, the light-transmissive pressurizing member 100, and the press unit 700 can be installed on the light-transmissive pressurizing member conveying unit 140 and the support unit 150 seen in FIG. 2 earlier. The light-transmissive pressurizing member conveying unit 140 can be realized as being vertically conveyable in the vertical direction by vertical conveying means (for example, a motor and a ball screw device) as an example, and the support unit 150 can be realized by a gantry device as an example.

[0252] Therefore, when the electronic component and the substrate, which are the bonding objects 11, are loaded, the holder unit 500, the translucent pressing member 100, and the press unit 700 are vertically conveyed upward so that the bonding object 11 can be loaded to a position directly below the translucent pressing member 100. After the bonding object 100 is loaded to a position directly below the pressing member 100, as the holder unit 500, the translucent pressing member 100, and the press unit 700 are vertically conveyed downward again to a position close to the bonding object 11, they are positioned in an atmospheric state for pressing.

[0253]

[0254] It is a principal - part perspective view showing the translucent pressing member of the laser - pressure head module according to the present invention. (a) illustrates the shape of the translucent pressing member having a single pressing surface according to one embodiment, and (b) illustrates another embodiment. As an example, it illustrates the shape of the translucent pressing member having a pressing surface divided so as to correspond to each electronic component.

[0255] Next, looking at the structure of the translucent pressing member 100 according to an embodiment of the present invention with reference to FIGS. 17a and 17b, as shown in FIG. 17a, the translucent pressing member 100 of the present invention is a square - plate - shaped base material 101. It has a structure in which a pressing surface 102 with a certain area protrudes upward. The area of the pressing surface 102 is desirably designed to correspond to the processing area of the bonding object 11 in consideration of the area of the bonding object 11 to be subjected to laser reflow processing at a time by a certain area.

[0256] At that time, the area of the pressing surface 102 is formed to be narrower than the area of the base material 101 and has at least one or more stepped portions 101a around the pressing surface 102. Further, on the side surface of the base material 101, the bottom surface, and the side surface of the stepped portion 101a except for the pressing surface 102, a laser - light blocking layer 103 and a shadow display are further formed to prevent the light beam of the laser light.

[0257] On the one hand, referring to FIG. 17b, looking at the structure of the translucent pressing member 100 according to another embodiment of the laser pressing head module of the present invention, in FIG. 17a seen previously, a single pressing surface 102 was formed, but in FIG. 17b, in order to contact and press each of the plurality of electronic components included in the bonding object 11, the pressing surface 102 has a structure divided into a grid so as to correspond to the area of each electronic component. For this reason, in the structure as shown in FIG. 17b, it is necessary to design and process the pressing surface 102 so as to accurately correspond to the occupied area of each electronic component to be subjected to laser reflow processing.

[0258] Also in this case, as shown in FIG. 17b, a laser light blocking layer 103 (shadow indication) is further formed on the side surface of the base material 101 other than the plurality of pressing surfaces 102 divided into a grid, the bottom surface and the side surface of the stepped portion 101a.

[0259] The laser light blocking layer 103 can generally be formed of various forms of special coating layers that absorb or reflect light. For example, it can be implemented as one or a composite layer of two or more of an Inconel coating layer that absorbs laser beams, a diffuse reflection processing layer in the form of frosted glass, or an HR (High Reflection) coating layer that reflects laser beams. By coating the laser light blocking layer 103, the laser beam is accurately irradiated only to the electronic components of the bonding object 11 through the pressing surface 102 of the translucent pressing member 100, so that thermal damage to the substrate and damage caused thereby due to the laser beam being irradiated to the adjacent printed circuit board (PCB) portion around the electronic components are prevented.

[0260]

[0261] FIG. 18 is an operating state diagram showing a state in which the translucent pressing member according to the present invention is mounted on the pressing head, and FIG. 19 is an enlarged view of the main part of FIG. 18.

[0262] Referring to FIGS. 18 and 19, as described above, the translucent pressing member 100 of the present invention has a structure in which a pressing surface 102 having an area smaller than the area of the base material protrudes from the bottom surface of the rectangular base material 101. At this time, at least one stepped portion 131a is formed between the base material 101 and the pressing surface 102. As shown in FIG. 15, the stepped portion 101a is used for attaching the translucent pressing member 100 to the holder unit 500 of the reflow device.

[0263] On the other hand, a silicon damper layer 104 can be further formed on the pressing surface 102. Generally, electronic components arranged on a printed circuit board (PCB) constituting the bonding object 11 are not completely flat due to the characteristics of the ductile circuit board and have their own flexure. As a result, it can be understood that each electronic component is arranged at different heights rather than at the same height on the horizontal line along the curved surface of the ductile circuit board.

[0264] At this time, when the pressing surface 102 of the translucent pressing member 100 presses the electronic components located at different heights on the curved surface of the ductile circuit board for the bonding process, the electronic components located at relatively high positions receive a greater pressing force than the electronic components located at low positions. As a result, the solder located below the electronic components at high positions may not be properly reflowed due to excessive pressing force, which may cause bonding failure.

[0265] Therefore, by further forming a silicon damper layer 104, which is a translucent elastic body according to an embodiment of the present invention, on the pressing surface 102, even if an excessive pressing force acts on the electronic components located above, the silicon damper layer 104 performs a damping function of absorbing a certain amount of the excessive pressing force.

[0266] On the one hand, when the translucent pressing member 100 presses an electronic component, a laser beam is irradiated from the first or second laser module 310, 320 located above the translucent pressing member 100. The laser beam is irradiated onto the electronic component through the translucent pressing member 100, and thermal energy for reflow is transmitted.

[0267] Referring to FIG. 19, when a laser beam is irradiated through the translucent pressing member 100, since the laser light blocking layer 103 (shadow indication) is formed on the side surface of the base material 101, the bottom surface and the side surface of the stepped portion 101a, as a result, the laser beam is blocked so as not to leak to all other portions except the pressing surface 102.

[0268] Also, for uniform laser reflow processing, in the present invention, the shape and the protruding height of the pressing surface 102 are also presented as the main considerations in the design of the translucent pressing member 100. For example, as shown in FIG. 17a, when the pressing surface 102 is not formed in a square structure but is formed in a rectangular structure, since the side surface area of the long side is larger than that of the short side of the rectangle, it can be predicted that the thermal energy by the laser beam on the long side is lost faster.

[0269] When such a deterioration phenomenon occurs, since the thermal energy is not uniformly transmitted to the plurality of electronic components pressed in a state of being disposed below the pressing surface 102, the possibility of bonding failure of the electronic components at a position lower or higher than the appropriate bonding temperature is greater. According to a desirable embodiment, by designing the bottom surface shape of the pressing surface 102 into a square structure, heat dissipation through the side surface of the pressing surface 102 becomes uniform in the vertical and horizontal directions.

[0270] Also, even when the protruding height h of the side surface of the pressing surface 102 is formed too high, since there is a possibility that a large amount of heat dissipation through the side surface of the stepped portion 101a may occur, it is most desirable to minimize the protruding height h of the pressing surface 102 or the depth of the lattice groove 102a recessed between the divided pressing surfaces 102 within several millimeters.

[0271]

[0272] On the one hand, FIGS. 20a to 20c are schematic views showing various embodiments of the light-transmissive pressing member according to the present invention. FIG. 20a shows the case where the pressing surface edge is not processed, FIG. 20b shows the case where the pressing surface edge is chamfered, and FIG. 20c shows the case where the pressing surface edge is rounded.

[0273] Referring to the attached FIGS. 20a, b, and c, it has been described that a protective film 200 is provided below the light-transmissive pressing member 100 of the present invention as shown in FIG. 2 above to prevent the adsorption of gases (fumes). At that time, when the light-transmissive pressing member 100 is moved downward as shown in FIG. 20a to press the bonding object 11, the protective film 200 is also pressed together with the light-transmissive pressing member 100, and it is understandable that the protective film 200 is in contact with the edges on both sides of the pressing surface 132 at that time.

[0274] However, as described above, it can be predicted that when the protective film 200 repeatedly contacts both edges of the pressing surface 102, eventually, problems such as the protective film 200 being torn or damaged will occur.

[0275] Therefore, in order to prevent this blockage, as shown in FIG. 20b, both ends of the pressing surface 102 are chamfered, or as shown in FIG. 20c. By rounding both ends in this way, additional considerations are presented during the design of the light-transmissive pressing member 100.

[0276]

[0277] Hereinafter, FIG. 21 is a cross-sectional view of a main part schematically showing the overall device configuration of the laser pressing head module according to an embodiment of FIG. 13, FIG. 22 is a plan view of the main part of FIG. 21, and FIG. 23 is an enlarged perspective view of the pressing unit of the laser pressing head module according to an embodiment of FIG. 13.

[0278] Hereinafter, with reference to the above drawings, the detailed configuration of the laser pressurization head module of the present invention and the operating relationship by pressurization and laser beam irradiation will be described in more detail according to an embodiment as follows.

[0279] First, referring to FIGS. 21 and 22, the pressurization head of the present invention is provided with a light-transmissive pressurization member 100 for transmitting the laser beam irradiated from the laser sources 310 and 320 while pressing the electronic component 11, which is an object to be bonded. At this time, the light-transmissive pressurization member 100 is mounted in a state of being inserted into a through hole formed in the center of the plate-shaped holder unit 500. Thereby, when the holder unit 500 is moved downward, the light-transmissive pressurization member 100 mounted on the holder unit can also move downward together and pressurize the electronic component 11 located thereunder.

[0280] In addition, press units 700 are arranged adjacent to each edge portion of the holder unit 500 in a non-contact state. First, the lower part of the holder unit 500 is supported by a pressure balancer 710, and the pressure balancer 710 is a buffer that pressurizes and cancels out the self-weights of the light-transmissive pressurization member 100 and the holder unit 500 in the opposite direction. As a component that plays a role, as an example, it can be implemented by an air cylinder or an elastic spring.

[0281] Therefore, after canceling out the basic self-weights of the light-transmissive pressurization member 100 and the holder unit 500 to a zero (0) value by the pressure balancer 710, it will wait in a state for pressurizing the light-transmissive pressurization member 100.

[0282]

[0283] On the other hand, referring to FIG. 23, when looking in detail at other component configurations of the press unit 700, it includes a press bracket 720 having a shape that wraps around each edge portion of the holder unit 500 in a non-contact state, pressure cylinders 730a, 730b, 730c, 730d fixedly installed at the upper ends of the press bracket, and pressure sensors 740 provided at the ends of the cylinder rods of the pressure cylinders 730a, 730b, 730c, 730d.

[0284] At this time, the pressure sensing sensor 740 can be realized as a load cell as an example. When the cylinder rods of the pressure cylinders 730a, 730b, 730c, 730d are pulled out and each edge portion of the holder unit 500 is pushed in and pressurized, it constantly measures this and serves to check whether a pressure above the appropriate pressure is applied and feedback this.

[0285] Therefore, as described above, the pressing head of the present invention irradiates the light-transmissive laser beam while pressing and pressurizing a plurality of electronic components 11 simultaneously using the light-transmissive pressing member 100 having a certain area, so that the reflow process can be performed at once. Compared with the conventional method of placing a small light-transmissive pressing member for each electronic component and pressurizing it by its own weight, there is an effect of significantly improving productivity.

[0286] For this reason, according to the present invention, the pressure cylinders 730a, 730b, 730c, 730d are separately installed so that the pressing force can be set independently for each corner of the holder unit 500, and a large-area pressing force adjustment is configured to be possible. Also, the pressure cylinders 730a, 730b, 730c, 730d can be realized by adopting precision pneumatic cylinders (hereinafter, positive hole cylinders) as an example that can precisely adjust the pressing force in Kgf units. Thus, according to various variable factors such as the bending state of the PCB substrate, by the operator adjusting the set pressures of the pressure cylinders 730a, 730b, 730c, 730d to be different from each other, the planar pressure balance of the large-area light-transmissive pressing member 100 of the present invention can be easily adjusted compared with the prior art.

[0287] On the other hand, when a pressure equal to or higher than the set pressure is applied, which is different from the pressures set for the respective pressure cylinders 730a, 730b, 730c, and 730d, the pressure sensor 740 coupled to the end of the cylinder rod 731 of the pressure cylinders 730a, 730b, 730c, and 730d senses this and feeds it back to a control unit (not shown). Therefore, when a pressure equal to or higher than a certain level is detected, the control unit performs an auto - balance process to adjust to the set pressure value or generates an alarm so that an operator can easily manually adjust the set pressures of the respective pressure cylinders 730a, 730b, 730c, and 730d as needed.

[0288] Also, although not shown in FIGS. 21 to 23, the holder unit 500, the light - transmissive pressurizing member 100, and the press unit 700 are provided on the light - transmissive pressurizing member conveyance unit 140 and the support unit 150 seen in FIG. 2 earlier. The light - transmissive pressurizing member conveyance unit 140 can be realized as being vertically conveyable in the vertical direction by, for example, vertical conveyance means (e.g., a motor and a ball screw device), and the support unit 150 can be realized as a gantry device, for example.

[0289] Therefore, when the electronic component and the substrate, which are the bonding objects 11, are loaded, the holder unit 500, the light - transmissive pressurizing member 100, and the press unit 700 are vertically conveyed upward so that the bonding objects 11 can be loaded to a position directly below the light - transmissive pressurizing member (100). After the bonding objects 100 are loaded to a position directly below the pressurizing member 100, as the holder unit 500, the light - transmissive pressurizing member 100, and the press unit 700 are vertically conveyed downward again to a position close to the bonding objects 11, they are positioned in an atmospheric state for pressurization.

[0290]

[0291] On the other hand, referring to FIGS. 21 and 22, above the holder unit 500, an ionizer 800 is further provided to remove contamination such as dust and other particles that settle on the upper surface of the translucent pressure member. The translucent pressure member 100 can be realized, for example, with a Quartz material. Even if the space where the process according to the present invention proceeds is a clean room environment, if some particles settle and are repeatedly stacked up, damage such as burning of the particles may be caused by the irradiation of the laser beam.

[0292] As a result, if the burning of the particles is repeated over a long period, the upper surface of the translucent pressure member 100 will become increasingly discolored, and ultimately, there is a possibility of damage such as cracks occurring in the translucent pressure member 100. Therefore, the ionizer 800 will prevent the adsorption of particles in advance, such as removing the generation of static electricity on the upper surface of the translucent pressure member 100 at any time.

[0293]

[0294] FIG. 24 is a perspective view according to an embodiment of the input area configuration and operation relationship of the bonding object transfer module according to the present invention. Hereinafter, referring to FIG. 24, looking at the mechanism configuration and operation relationship of the input area (loading area) of the bonding object according to the present invention, it is as follows.

[0295] The input area configuration first includes an input conveyor 910 for loading a bonding object of a certain area (for example, a PCB with a plurality of electronic components seated thereon) for laser reflow processing. The input conveyor 910 has a handle character On both sides of the upper part of the conveyor frame 912 having a shape bent in the form of JPEG0007679133000002.jpg1117, there is provided a conveyor frame 912 having a shape bent by a pair of wires for conveyor conveyance of the bonding object 11. Orbit means 911 is provided, and the wire orbit means 911 is coupled to the rotation axis of the orbit drive motor 913. Also, on one side of the conveyor frame 912, a width adjustment motor 915 is provided so as to expand or contract the width of the input conveyor 910 in order to accommodate bonding objects 11 of different sizes.

[0296] Also, since a horizontal conveyance unit 920 is mounted on one end of the conveyor frame 912, as the horizontal conveyance unit 920 is conveyed in the horizontal direction, the conveyor frame 912 is also moved together in the horizontal direction.

[0297] On the other hand, since a preheating stage 914 is provided on the upper part of the conveyor frame 912, while the bonding object 11 conveyed by the wire orbit means 911 stays above the preheating stage 914 before being introduced into the laser reflow processing area, the bonding object 11 is continuously preheated to a predetermined temperature (for example, 150 ° C) so that the temperature rises rapidly and stably to the melting temperature of the desired solder (for example, 250 ° C) by irradiation with a laser beam during laser reflow.

[0298] On the other hand, in order for the input conveyor 910 to be horizontally conveyed on the preheating stage 914 in a preheating state and introduced into the reflow processing area, the bonding object 11 must be accurately transferred without fail onto the vacuum chuck 940. At this time, referring to FIG. 21, a picker unit 930 is further provided above the vacuum chuck 940, and the picker unit 930 includes a vacuum suction pad 931 for adsorbing the bonding object, a cylinder 932 for driving the vacuum suction pad in the vertical direction, and a support frame 933 for fixing the vacuum suction pad 931 and the cylinder 932.

[0299] Therefore, when the input conveyor 910 moves toward the vacuum chuck 940, the vacuum suction pad 931 of the picker unit 930 is moved upward by the drive of the cylinder 932. Then, when the bonding object 11 is positioned below the vacuum suction pad 931, the vacuum suction pad 931 is moved downward to adsorb the bonding object 11 and then conveyed upward again. After that, when the input conveyor 910 is horizontally conveyed back to its original position and exits from below the vacuum suction pad 931, the vacuum suction pad 931 is moved downward again to repeat the operation of placing the bonding object 11 on the vacuum chuck 940.

[0300] After that, a horizontal conveying means, for example, a linear motor 941, is provided below the vacuum chuck 940. Thus, by the operation of the linear motor 941, both the vacuum chuck 940 and the bonding object 11 are moved to the laser reflow processing area.

[0301] In addition, a vision unit 934 is further provided on one side of the vacuum chuck 940 to constantly monitor whether the bonding object 11 is accurately seated and aligned on the vacuum chuck in the input area, i.e., whether it is a normal load.

[0302]

[0303] On the other hand, FIG. 25 is a perspective view showing the output area configuration and operation relationship of the bonding object conveying module according to the present invention in accordance with an embodiment. Hereinafter, with reference to FIG. 25, the mechanism configuration and operation relationship of the output area (unloading area) of the bonding object according to the present invention will be examined as follows.

[0304] The configuration of the output conveyor 950 is almost the same as that of the input conveyor 910 seen above. However, the difference from the configuration of the input conveyor 910 is that the preheating stage 914 for preheating the bonding object 11 is omitted on the output conveyor 950.

[0305] Therefore, when the bonding object 11 that has completed the laser reflow process is conveyed to the output area (unloading area) while seated on the vacuum chuck 940, the picker unit 970 adsorbs the bonding object 11 on the vacuum chuck 940 in the reverse order of loading and transfers it to the output conveyor 950. Then, after the output conveyor 950 performs horizontal conveyance, the bonding object 11 is unloaded outside the apparatus via the wire track means 951.

[0306]

[0307] Figures 26a and 26b are exemplary diagrams showing the configuration and operating relationship of the vacuum chucking means of the bonding object conveyance module according to the present invention. Figure 26a is a plan view and a side cross-sectional view showing the configuration of one embodiment of the porous adsorption plate, and Figure 26b is a plan view and a side cross-sectional view showing the configuration of another example of the porous adsorption plate.

[0308] First, referring to Figure 26a, the configuration of the vacuum chuck 940 according to one embodiment of the present invention has an upper surface composed of a plurality of porous adsorption plates, and the porous adsorption plates are for adsorbing the central portion of the bottom surface of the bonding object 11. It is divided into a rectangular central adsorption plate 943 and an edge adsorption plate 944 that is arranged so as to surround the periphery of the central adsorption plate and adsorbs the edge portion of the bottom surface of the bonding object 11.

[0309] At this time, referring to the plan view, when the bonding object 11 with a certain area is seated on the porous adsorption plates 943 and 944, and is vacuum-adsorbed by suction means (not shown in the drawing) such as an air compressor provided on the central adsorption plate 943 and the border adsorption plate 944, the bonding object 11 is fixed to the upper surface of the vacuum chuck 940 in a widely extended state.

[0310] Also, referring to the attached side sectional view, the central suction plate 943 and the edge suction plate 944 are formed separately from each other with a certain interval therebetween. At this time, since the suction plate lifting unit 980 is installed below the central suction plate 943, when the central suction plate 943 is required, that is, in the configuration of the previously seen embodiment, it may have another embodiment configuration in which the picker units 930 and 970 are omitted. That is, the central suction plate 943 can directly receive the bonding object 11 from the input conveyor 910. In this case, in order for the central suction plate 943 to directly receive the bonding object 11 from the input conveyor 910, after being lifted upward, the central suction plate 943 immediately takes over the bonding object 11 from the wire track means 911 of the input conveyor 910 and then descends downward again, and the present invention can fully achieve its intended purpose even in this driving form.

[0311] Also, a heating block 942 can be further provided directly below the central suction plate 943. The heating block 942 serves to preheat the bonding object 11 to a predetermined temperature while the bonding object is being carried in until before the laser reflow process, similar to the preheating stage 914 of the input conveyor 910.

[0312]

[0313] On the other hand, Fig. 26b shows the configuration and operation relationship of another embodiment of the porous suction plate according to the present invention. The difference from the configuration of the previously seen embodiment in Fig. 26a is that the edge suction plate 945 is made of an aluminum material which is not the same porous material as the central suction plate, and a plurality of suction holes 944a are further formed in the circumferential direction adjacent to the central suction plate 943 of the edge suction plate 945 in order to more strongly adsorb the bottom edge portion of the bonding object 11. Since the other configurations and operation relationships are the same as those in the case of the embodiment with reference to Fig. 26a, detailed description is omitted.

[0314] Also, as shown in FIGS. 26a and 26b, by adjusting the vacuum adsorption forces of the central adsorption plate 943 and the border adsorption plates 944 and 945 of the vacuum chuck 940, it is expected that the unique bending or wrinkles of the printed circuit board (PCB), for example, the flexible circuit board (Flexible PCB) of the bonding object 11 can be stretched to some extent. As a result, the vertical heights of the electronic components seated on the substrate are also improved to be approximately at the same point. Therefore, it is possible to obtain the effect of improving the process defects by preventing excessive pressure from acting on specific electronic components during laser reflow.

[0315]

[0316] FIG. 27 is a side view schematically showing the configuration and operation relationship of a multi-laser module according to another embodiment of the present invention. FIG. 28 is a perspective view of a main part showing an enlarged temperature sensing sensor configuration of FIG. 27, and FIG. 29 is a plan view of a main part showing an enlarged bonding object configuration of FIG. 28.

[0317] Hereinafter, with reference to FIGS. 27 to 29, the configuration and operation relationship of a multi-laser module according to another embodiment of the present invention will be described.

[0318] First, referring to FIG. 27, a multi-laser module according to another embodiment of the present invention includes a pair of first laser modules 310 and a second laser module 320. An infrared temperature sensing sensor 810 is provided between the first laser module 310 and the second laser module 320 to measure the temperature of the laser beam superposed and irradiated from the first and second laser modules 310 and 320.

[0319] On one hand, beam profilers 318 and 328 are respectively provided for the first laser module 310 and the second laser module 320, and the laser beam output, intensity, etc. of the first and second laser modules 310 and 320 are constantly monitored. The configuration of the beam profilers 318 and 328 is, for example, to irradiate or transmit a part of the laser beam output on the laser beam path of the first and second laser modules 310 and 320 to the beam profiler, so that the output, intensity, etc. of the laser beam can be measured.

[0320] According to one embodiment, the infrared temperature sensing sensor 810 may be a single infrared temperature sensing sensor 810, and the single infrared sensing sensor measures the surface temperature value of the region 12 where the laser beams are superposed and irradiated from the first and second laser modules. At this time, the single infrared temperature sensing sensor 810 measures the temperature of a large number of points in the region where the laser beams are superposed and irradiated in sequence, so as to measure the overall temperature distribution value of the region where the laser beams are superposed and irradiated.

[0321] When such a temperature distribution value is measured to be non-uniform, for example, when the temperature value is measured higher than the solder melting temperature at a certain point, overflow bonding defects due to overheating of the solder may occur. Conversely, if the temperature is measured lower than the solder melting temperature, there may be a bonding defect that the solder does not melt sufficiently and cannot be connected.

[0322] Therefore, in the present invention, by constantly measuring the temperature of the region where the infrared temperature sensing sensor 810 is superposed and irradiated, the output or intensity of each laser beam output from the first or second laser module 310, 320, the shape of the beam, etc. are adjusted to compensate the temperature distribution value in the superposed irradiation region 12.

[0323] On the other hand, in another embodiment of the present invention, a plurality of infrared temperature sensors 810 may be provided. Referring to FIG. 28, the plurality of infrared temperature sensors of the present invention may be composed of, for example, five temperature sensors 810#1, 810#2, 810#3, 810#4, and 810#5. One temperature sensor 810#1, 810#2, 810#3, and 810#4 may be arranged at each edge portion in the arrangement structure, and one temperature sensor 810#5 may be arranged at the central portion. Therefore, the five infrared temperature sensors 810#1, 810#2, 810#3, 810#4, and 810#5 irradiate infrared beams simultaneously. In this case, as shown in FIG. 29, the infrared beams are irradiated and the temperature is measured for the electronic components 11b#1, 11b#3, 11b#7, 11b#9 located at each edge portion of the square region 12 where the laser beams are overlapped and irradiated and the electronic component 11b#5 located at the central portion.

[0324] At this time, the position and number of the electronic components 11b whose temperature is measured as described above are not specified, and the temperature of the substrate surface where no electronic component is arranged can also be measured. In order to obtain a more accurate temperature distribution value of the region where the laser beams are overlapped and irradiated, it can be achieved by measuring the temperature values of as many electronic components and substrates as possible.

[0325] On the other hand, in another method of compensating the temperature distribution value, it is also possible to compensate the temperature distribution value when adjusting the irradiation angle, height, etc. of the first or second laser beam.

[0326]

[0327] FIGS. 30a to 30e are relational diagrams showing the operation relationship of each step of the laser reflow method of the present invention. Hereinafter, when looking at each step of the laser reflow method according to an embodiment, it is as follows.

[0328] First, FIG. 30a is a state diagram in which the translucent pressing member 100 has moved above the center line Cn+1. When the pressing surface 102 of the translucent pressing member 100 is located on the center line Cn+1, the vision unit 934 captures an image of the electronic component 11b located below the pressing surface 102 of the translucent pressing member 100. At this time, when viewed from the side as shown in FIG. 30a, the vision unit 934 determines whether the electronic components 11b are arranged symmetrically with respect to the center line Cn+1 of the pressing surface 102 of the translucent pressing member 100.

[0329] That is, with the shape in which the electronic components 11b located directly below the pressing surface 102 of the translucent pressing member 100 are arranged positioned corresponding to the area of the pressing surface 102, for example, in a state where the electronic components 11b are arranged in three rows as shown in FIG. 10a, it is determined whether the electronic components 11b are arranged symmetrically by 1.5 rows on each side with respect to the center line Cn+1 of the pressing surface 102. Thereby, when the pressing surface 102 of the translucent pressing member 100 presses the range (area) in which the electronic components 11b are arranged in three rows, pressure is not concentrated on either side, and uniform pressing can be achieved.

[0330] Also, referring to the drawings, the electronic component 11b of the bonding object 11 is in a state of being arranged at a position where it is bonded together with the solder 11c for bonding on the upper surface of the substrate 11a. At this time, it is in a state of being vacuum-sucked and fixed by the vacuum chuck 940 under the silver of the substrate 11a. At this time, since the heating block 942 is provided inside the vacuum chuck 940, the substrate 11a, the electronic component 11b, and the solder 11c, which are the bonding objects 11, are continuously preheated to a predetermined temperature. For example, the preheating temperature is preferably set below the melting temperature of the solder, and can be maintained below 200°C, which is a temperature range in which no thermal damage is caused even if the substrate 11a and the electronic component 11b are exposed for a certain period of time or more.

[0331] If the bonding object 11 is not preheated as described above, during the laser reflow process in this step, the bonding object 11 must be rapidly heated from room temperature to the melting temperature of the solder 11c only by the thermal energy of the laser beam. In this case, the rapid heating may cause bonding defects such as overflow in the solder 11c. Therefore, if the temperature is increased step by step from the preheating temperature to the melting temperature of the solder 11c, the solder 11c can melt stably and the bonding defects can be minimized. For example, here, the melting temperature of the solder 11c may vary depending on the material of the solder, but it may be 200°C or higher, which is the melting temperature of a general solder paste.

[0332]

[0333] FIG. 30b is a state diagram in which the light-transmissive pressing member 100 is pressed and irradiated with a laser beam along the center line Cn+1. As shown in FIG. 10a, when it is determined that the center line Cn+1 of the pressing surface 102 of the light-transmissive pressing member 100 by the vision unit 934 coincides with the center line of the electronic component 11b to be bonded, the light-transmissive pressing member 100 moves downward to press the electronic component 11b.

[0334] At this time, a laser beam can be irradiated simultaneously or sequentially with the pressing of the light-transmissive pressing member 100. For example, when the light-transmissive pressing member 100 is pressed, a laser beam can be superimposed and irradiated on the electronic component 11b from the multi-laser module, the first laser module 310, and the second laser module 320 located above at the same time.

[0335] Thereby, the bonding object 11 is gradually heated from the preheating temperature to the melting temperature of the solder 11c by the superimposed laser beam, and finally, the solder 11c located below the electronic component 11b melts while the bonding of the electronic component 11b to the substrate 11a is completed. (The height difference before and after bonding is denoted as hc in FIG. 30a.)

[0336]

[0337] Figure 30c is a state diagram in which the translucent pressing member has moved above the center line Cn+2, Figure 30d is a state in which the position of the translucent pressing member is corrected to a new center line Cn+2′, and Figure 30e is a state diagram in which the translucent pressing member is pressed and laser-irradiated with the center line Cn+2′.

[0338] Referring to Figure 30c, after the previous laser reflow process is completed, the translucent pressing member 100 is horizontally transported to the center line Cn+2 of the three rows of electronic components 11b in order to press and perform laser reflow processing on the three rows of electronic components 11b within the next predetermined range. At this time, the vision unit 934 photographs the arrangement shape of the electronic components 11b disposed below the pressing surface 102 of the translucent pressing member 100 again.

[0339] By the way, at this time, as shown in Figure 30c, if it is determined that the electronic components 11b disposed below the pressing surface 102 of the translucent pressing member 100 are not symmetrically arranged with respect to the center line Cn+2, the pressing and laser irradiation are not immediately advanced. The reason is that when the translucent pressing member 100 is pressed in this state, since the electronic components 11b are asymmetrically arranged with respect to the center line Cn+2 of the pressing surface 102 of the translucent pressing member 100, the pressing force during pressing is biased toward one side, resulting in bonding failure.

[0340] Therefore, in order to prevent this, in the present invention, as shown in Figure 30d, the control unit (not shown) moves the horizontal position of the translucent pressing member 100 to a new center line Cn+2′, and accordingly, the horizontal position of the translucent pressing member 100 is corrected with the corrected center line Cn+2′. As a result, the horizontal position is corrected so that the electronic components 11b disposed below the translucent pressing member 100 are symmetrically arranged with respect to the corrected center line Cn+2′. In this state, as shown in Figure 30e, the translucent pressing member 100 moves downward to press the electronic components 11b and irradiate them with a laser beam.

[0341]

[0342] On the one hand, referring to FIG. 30e, the light-transmissive pressing member 100 moves along the corrected center line Cn+2' to proceed with pressing. At this time, the first and second laser modules 310 and 320 do not correct their horizontal positions along the corrected center line Cn+2', but irradiate laser beams based on the center line Cn+2 before correction.

[0343] The reason why the laser modules 310 and 320 do not correct their horizontal positions along the light-transmissive pressing member 100 as described above is that when laser beams are irradiated based on the corrected center line Cn+2', there is a risk that the laser beams will be irradiated again on the electronic components where bonding has already been completed. If the laser beams are re-irradiated on the solder 11c that has undergone reflow processing, the solder 11c may melt again, resulting in bonding defects. Therefore, in the present invention, when pressing and laser irradiating the asymmetrically arranged electronic components 11b, only the light-transmissive pressing member 100 is horizontally transported to the corrected center line Cn+2' without correcting the positions of the first or second laser modules 310 and 320, and after correcting the position, pressing and laser irradiation are performed, thereby minimizing the occurrence of various bonding defect factors as described above.

[0344]

[0345] It is a state diagram showing the operation relationship of each step of the laser reflow method according to the present invention. Hereinafter, when looking at various bonding modes that can be combined according to each step according to the embodiments, it is as follows.

[0346] First, referring to FIG. 31a, the first bonding mode of the present invention is the most basic bonding mode. The pressing surface 102 of the light-transmissive pressing member 100 moves downward to contact the bonding object 11 without applying a pressing force, the laser beam is irradiated on the bonding object 11 through the light-transmissive pressing member 100, and then the irradiation of the laser beam is released and the light-transmissive pressing member 100 is moved upward.

[0347] At that time, in the stage where the light-transmitting pressing member 100 comes into contact without applying a pressing force, as shown in FIG. 13 above, it is connected by the motor 760 and the ball screw 750 by driving the motor 760. The press bracket 720 comes to move downward, and since the holder unit 500 and the light-transmitting pressing member 100 are mounted on the press bracket 720, finally, the light-transmitting pressing member 100 is moved downward by driving the motor.

[0348] Referring to FIG. 31b in the next step, when the light-transmitting pressing member 100 is moved downward and comes into contact with the electronic component 11b of the bonding object 11, a driving force is provided to move the light-transmitting pressing member 100 downward. The driving of the motor 760 is stopped, and the light-transmitting pressing member 100 comes into contact with the upper surface of the electronic component 11b without applying a pressing force. At that time, since the motor is in a locked state, the height of the light-transmitting pressing member 100 is fixed so that it does not move vertically either.

[0349] Next, as shown in the next step of FIG. 31c, with the light-transmitting pressing member 100 in contact with the upper surface of the electronic component 11b, the multi-laser module provided above the light-transmitting pressing member 100, that is, the first laser module 310 and the second laser module 320, irradiate the bonding object 11 with laser beams through the light-transmitting pressing member 100.

[0350] At this time, the laser beam can be transmitted as a homogenized laser beam to the plurality of electronic components 11b and solder 11c by being superposed and irradiated. As described above, the bonding object 11 has already been preheated at a certain preheating temperature, for example, less than 200°C. Therefore, even if the laser beam does not rapidly heat the bonding object 11 to the melting temperature of the solder 11c, for example, 250°C, it can be stably heated from the preheating temperature to the melting temperature of the solder 11c. As a result, when the laser reflow is started, since the pressure-applying surface 102 of the light-transmissive pressure-applying member 100 is in contact with the upper surface of the solder 11c, the electronic component 11b located above the solder 11c is confined so as not to bend or stretch upward when the solder 11c melts.

[0351] After that, when the soldering is completed, the irradiation of the laser beam is released and the light-transmissive pressure-applying member 100 is moved upward, thereby completing the first bonding mode.

[0352]

[0353] On the other hand, let's look at an embodiment of another bonding mode in which several steps are added in the first bonding mode.

[0354] Similar to the first bonding mode described above, in the second bonding mode, after the light-transmissive pressure-applying member 100 contacts the electronic component 11b of the bonding object 11, the pressure-applying cylinder 730 provided above the light-transmissive pressure-applying member 100 presses the light-transmissive pressure-applying member 100 at a constant pressure.

[0355] Thereafter, when the laser beam is irradiated while the translucent pressing member 100 presses the bonding object 11 as described above, as the solder 11c of the bonding object 11 melts, the pressing force is released. At this time, it is expected that the height of the electronic component 11b will be lowered due to the compression of the solder 11c by a certain height (see hc in Fig. 31a). When the motor 760 is unlocked in this state, the translucent pressing member 100 will gradually move downward due to its own weight. Eventually, the translucent pressing member 100 will move downward by the amount of the pressing force applied by the pressing cylinder 730, so the pressing force is maintained.

[0356] Therefore, the second bonding mode is different from the initial bonding mode in that the pressing force is applied before the laser beam is irradiated, and when the solder 11c to which the laser beam is applied melts, the translucent pressing member 100 also moves downward while maintaining the pressing force. As a result, since the pressing force applied to the solder 11c is kept constant when the solder 11c melts, it is expected to reduce the floating of the electronic component 11b and the connection failure of the solder 11c, and obtain a highly dense soldering effect.

[0357]

[0358] Also, the third bonding mode is the same as the first bonding mode described above in that after the translucent pressing member 100 contacts the electronic component 11b of the bonding object 11, the laser beam is irradiated without applying a pressing force.

[0359] After the laser beam is irradiated, the pressing cylinder 730 is driven to apply a certain pressing force to the translucent pressing member 100 and the bonding object 11. At this time, the motor 760 is locked and fixed so that the translucent pressing member 100 cannot move vertically, and only the pressing cylinder 730 applies the pressing force. The third bonding mode is different from the first bonding mode in that the pressing force is applied after the laser beam is irradiated.

[0360]

[0361] The fourth bonding mode is the same as the third bonding mode up to the stage of irradiating the laser beam, but there is a difference in that, instead of applying a pressing force after the irradiation of the laser beam, the height of the light-transmissive pressing member 100 is changed.

[0362] Therefore, when the irradiation of the laser beam starts, the lock of the motor is released, and the light-transmissive pressing member 100 gradually moves downward, and finally gradually presses the electronic component 11b and the molten solder 11c. Thus, it is possible to prevent bonding failure caused by the sudden application of a pressing force to the solder 11c melted by the laser beam.

[0363]

[0364] As described above, there are possibilities of various embodiments in terms of adjusting the pressure change due to the melting of the solder to prevent bonding failure in the bonding mode.

[0365] Therefore, the present invention is not limited only by the embodiments described above, and even if the detailed configuration, number, and arrangement structure of the device are changed, or the detailed steps are changed and added, the same effects can be produced. Thus, it is explicitly stated that those having ordinary knowledge in the relevant technical field can add, delete, and modify various configurations within the scope of the technical idea of the present invention.

[0366]

[0367] Description of Reference Numerals

[0368] 11: Bonding object 11a: Substrate

[0369] 11b: Electronic component 12: Laser overlapping irradiation region

[0370] 100: Light-transmissive pressing member 101: Base material

[0371] 101a: Step portion 102: Pressing surface

[0372] 102a: Lattice groove 103: Laser light blocking layer

[0373] 104: Silicon damper layer 200: Protection film

[0374] 210: Protection film conveying unit 310: First laser module

[0375] 318, 328: Beam profiler 320: Second laser module

[0376] 500: Holder unit 510: Lower plate

[0377] 520: Mask plate 600: Probe unit

[0378] 610: Probe 620: Probe conveying unit

[0379] 630: Probe bracket 700: Press unit

[0380] 710: Pressure balancer 720: Press bracket

[0381] 730: Pressing cylinder 740: Pressure sensing sensor

[0382] 750: Ball screw 760: Motor

[0383] 770: Guide member 780: Bearing joint

[0384] 790: Stopper 800: Ionizer

[0385] 810: Infrared temperature sensing sensor 811: Infrared irradiation point

[0386] 910: Input conveyor 920, 960: Horizontal conveying unit

[0387] 930, 970: Suction pad 934: Vision unit

[0388] 940: Vacuum chuck 942: Heating block

[0389] 943: Porous adsorption plate 950: Output conveyor

[0390] 980: Adsorption plate lifting unit

[0391]

Claims

1. A laser reflow method for a laser reflow apparatus in which a bonding object, which is a rectangular substrate on which a plurality of electronic components are arranged, is pressed against a light-transmitting pressure member, and a laser beam is irradiated through the light-transmitting pressure member to bond the electronic components to the substrate, comprising: a) before the light-transmitting pressure member presses the bonding object, a vision unit captures an image of a shape of electronic components arranged within a predetermined range located directly under a pressure surface of the light-transmitting pressure member; b) determining whether the photographed shape of the electronic components in the predetermined area is positioned to correspond to the pressure surface; c) when it is determined that the electronic component is positioned to correspond to the pressing surface, a light-transmitting pressing member is moved downward to press the bonding object, and a laser beam is irradiated onto the bonding object via the light-transmitting pressing member; d) stopping the irradiation of the laser beam to move the light-transmitting pressure member upward to release the pressure; and e) A laser reflow method using a laser reflow apparatus, comprising a step of horizontally transporting the light-transmitting pressure member to above a predetermined range of electronic components to be subjected to a next reflow process.

2. The step b) includes a step of: b1) determining whether the electronic components are positioned symmetrically with respect to a center line of the pressure surface of the light-transmitting pressure member when the photographed shape of the electronic components arranged within a predetermined range is viewed from the side; b2) if the shape of the photographed electronic component is positioned symmetrically with respect to the center line of the pressure surface of the light-transmitting pressure member, it is determined that the electronic component is positioned to correspond to the pressure surface, and if the electronic component is not positioned to correspond to the pressure surface, a step of adjusting the horizontal position of the light-transmitting pressure member so that the shape of the electronic component is positioned symmetrically with respect to the center line of the pressure surface of the light-transmitting pressure member is provided.

3. 2. The laser reflow method according to claim 1, wherein the laser beam is a superimposed laser beam emitted from two or more laser modules.

4. 4. The laser reflow method according to claim 3, wherein the two or more laser modules are arranged symmetrically with respect to each other, and the laser beams of each of the two or more laser modules have the same beam irradiation angle.

5. 5. The laser reflow method according to claim 4, wherein the laser beams are irradiated from the two or more laser modules simultaneously.

6. 5. The laser reflow method according to claim 4, wherein the laser beams are sequentially emitted from the two or more laser modules.

7. 2. The laser reflow method of claim 1, further comprising the step of preheating the bonding object at a lower portion before the step c).

8. 8. The laser reflow method according to claim 7, wherein the preheating of the bonding object at the lower portion maintains a surface temperature of the bonding object at less than 200[deg.] C.

9. 2. The laser reflow method of claim 1, wherein in step c), the surface temperature of the bonding object is heated to 200[deg.] C. or more by irradiating the bonding object with a laser beam through a light-transmitting pressure member.

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