Laser reflow method

Abstract

To improve the failure rate of a laser reflow device.SOLUTION: A laser reflow device according to the present invention, comprises: a laser pressurization head module that presses a bonding object formed of a plurality of electronic components arranged on a substrate by a light transmissive pressurization member, while irradiating a laser beam via the pressure member to bond the electronic components to the substrate; and a bonding object transfer module that transfers the bonding object in order to transfer the bonding object having transferred from one side of the laser pressurization head module to the other side thereof after passing through a reflow process of the laser pressurization head module.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laser reflow apparatus and a laser reflow method, and more particularly to a laser reflow apparatus that applies pressure to a plurality of electronic components arranged on a substrate by applying a laser while the electronic components are pressed with a light-transmitting pressure member, thereby simultaneously bonding the electronic components, and a laser reflow method using the apparatus. [Background technology]

[0002] Microlaser processing is an application field in industrial laser processing that requires micron-level precision and is widely used in the semiconductor, display, printed circuit board (PCB) and smartphone industries. Memory chips, which are used in all electronic devices, have developed technologies to minimize circuit spacing to achieve high integration, performance and ultra-high-speed communication speeds. However, technology that simply reduces circuit line width and line width spacing is no longer sufficient to meet the required standards, and memory chips have now been vertically stacked. TSMC has already developed stacking technology for up to 128 layers, and Samsung Electronics and SK Hynix are applying stacking technology for up to 72 layers to mass production.

[0003] In addition, there has been intense research and development into technologies that attempt to integrate memory chips, microprocessor chips, graphic processor chips, wireless processor chips, sensor processor chips, etc. into a single package, and a considerable level of technology has already been put into practical use.

[0004] However, in the development of these technologies, the increased number of electrons required for signal processing inside ultra-high-speed, ultra-high-capacity semiconductor chips has led to increased power consumption and cooling issues. Furthermore, the need for ultra-high-speed and ultra-high-frequency signal processing for a greater number of signals has created the technical problem of the need to transmit large amounts of electrical signals at ultra-high speeds. Furthermore, the need for more signal lines has led to the need for signal interface lines to the outside of the semiconductor chip to be handled in a one-dimensional manner. Therefore, various methods have been adopted, including a ball grid array (BGA) method (called Fan-In BGA or Fan-in Wafer-Level Package (FIWLP)) that handles signal interface lines to the outside of the semiconductor chip in two dimensions underneath the semiconductor chip, and a method (called Fan-out BGA or Fan-out Wafer-Level Package (FOWLP) or Fan-out Panel-Level Package (FOPLP)) that places a signal layout redistribution layer underneath an ultra-fine BGA layer underneath the chip, with a second fine BGA layer underneath.

[0005] In recent years, semiconductor chips with thicknesses of less than 200 μm, including the EMC (Epoxy-Mold Compound) layer, have been appearing. When a mass reflow (MR) process, such as the thermal reflow oven technology that is the standard for conventional surface mount technology (SMT), is used to attach these ultra-hard, thin semiconductor chips, which are only a few hundred microns thick, to ultra-hard, thin PCBs, the semiconductor chips are exposed to air temperatures of 100 to 300 degrees Celsius for several hundred seconds, which can lead to various types of solder bonding failures, such as chip-boundary warpage, PCB-boundary warpage, and random-bonding failures due to thermal shock, caused by differences in the coefficient of thermal expansion (CTE).

[0006] Looking at the configuration of laser reflow equipment, which has been gaining attention recently, the laser head module presses the bonding object (semiconductor chip or integrated circuit IC) for a few seconds and irradiates it with a laser to bond it. The bonding is performed by irradiating a laser in the form of a surface light source that corresponds to the size of the semiconductor chip or integrated circuit (IC). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Korean Patent No. 0662820 [Patent Document 2] Korean Patent Application No. 2017-0077721

[0008] Regarding such a pressure-type laser reflow device, Patent Document 1 discloses the configuration of a flip chip heating and compression bonding module that irradiates a laser onto the back surface of a flip chip to heat the flip chip while compressing the flip chip to a carrier substrate.

[0009] However, the conventional pressure-type laser reflow device disclosed in Patent Document 1 is separated into a means for adsorbing the chip and moving it to the bonding position, and a means for heating the back surface of the chip via a laser and pressing the chip to a carrier substrate. Therefore, when bonding multiple semiconductor chips such as semiconductor strips, the operation of applying pressure to one semiconductor chip and irradiating the laser must be repeated for each semiconductor chip, which increases the working time.

[0010] Meanwhile, referring to Patent Document 2, the laser reflow device configuration described in the patent states that bonding can be performed by either a pressure head pressing multiple flip chips simultaneously while a laser head moves horizontally and irradiates each flip chip one by one with a laser, or a single laser head irradiating multiple flip chips with a laser simultaneously.

[0011] However, according to the conventional laser reflow device configuration of Patent Document 2 mentioned above, since a single laser source is used, the laser beam is incident on multiple flip chips arranged on a substrate at multiple angles, making it difficult to irradiate a uniform laser beam. Therefore, it is expected that there will be many technical difficulties in uniformly reflowing multiple flip chips without defects.

[0012] Therefore, the conventional laser reflow apparatus disclosed in Patent Documents 1 and 2 applies pressure and irradiates laser light to each flip chip one by one, lengthening the overall operation time. Furthermore, even if a single laser beam is irradiated to multiple flip chips arranged horizontally on various substrate sizes for multiple processes, it is practically difficult to transfer uniform heat energy to each flip chip. Therefore, much research, development, and effort are required to improve the bonding failure rate. Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention was invented to solve the above-mentioned problems, and is configured to easily adjust the pressure and laser projection area to be processed at one time by replacing the light-transmitting pressure member to correspond to various substrate sizes. Therefore, it is an object of the present invention to provide a laser pressure head module for a laser reflow apparatus that can simultaneously press and mass-process multiple electronic components by laser reflow, while significantly reducing the defect rate.

[0014] Another object of the present invention is to provide a laser pressure head module for a laser reflow device that is capable of mass processing while significantly reducing the defect rate by applying pressure to multiple electronic components simultaneously and irradiating a homogenized laser beam.

[0015] In addition, the present invention is configured to independently set and adjust pressure at each edge of a plate-shaped holder unit to which a transparent pressure member is attached in order to accommodate various sizes of substrates. Therefore, an object of the present invention is to provide a laser pressure head module for a laser reflow apparatus that can simultaneously apply pressure and irradiate a laser beam to multiple electronic components to reflow them at once, thereby enabling mass processing while significantly reducing the defect rate.

[0016] The present invention is configured such that a conveyor system can simultaneously transport bonding objects, each of which has multiple electronic components mounted on a board, to and from a reflow treatment area, regardless of their size, and the bonding objects are gradually preheated to a predetermined temperature during transport, thereby achieving a stable temperature rise to the solder melting point during laser reflow treatment without defects. Therefore, it is an object of the present invention to provide a laser reflow apparatus that can process multiple electronic components at once by simultaneously applying pressure and irradiating them with a laser beam, thereby significantly reducing the defect rate while enabling mass processing.

[0017] The present invention is configured to prevent bonding failure of specific electronic components by precisely monitoring the area where multiple laser beams are superimposed with multiple temperature sensors, thereby instantly detecting and compensating for temperature imbalances between the substrate and electronic components that constitute the bonding target.As a result, it is possible to provide a multi-laser module for a laser reflow device that can simultaneously pressurize and irradiate laser beams on multiple electronic components to reflow them at once, enabling mass processing while significantly reducing the rate of bonding failures due to temperature imbalances.

[0018] The present invention adjusts the position of the electronic components located below the light-transmitting pressure member so that they are positioned exactly at the center of the pressure surface of the light-transmitting pressure member before pressure is applied, thereby enabling the pressure transmitted to the electronic components by the light-transmitting pressure member to be applied evenly without being concentrated on one side. Therefore, it is an object of the present invention to provide a laser reflow method for a laser reflow apparatus that can process a large number of electronic components at once by simultaneously applying pressure to them and irradiating them with a laser beam to reflow them at once, thereby enabling mass processing while significantly reducing the defect rate.

[0019] The present invention aims to provide a laser reflow method for a laser reflow device that can reflow a large number of electronic components at once without bonding defects, by sequentially controlling the pressurization and laser beam irradiation processes for a plurality of electronic components according to preset conditions, thereby significantly improving the defect rate. [Means for solving the problem]

[0020] In order to achieve the above object, the present invention provides a laser pressure head module that applies pressure to a bonding object consisting of a plurality of electronic components arranged on a substrate with a light-transmitting pressure member and irradiates a laser beam through the pressure member to bond the electronic components to the substrate; The bonding object transport module transports the bonding object carried in from one side of the laser pressure head module, so that the bonding object can be subjected to the reflow treatment of the laser pressure head module and then transported out to the other side.

[0021] The laser pressure head module further includes a holder unit for attaching the light-transmitting pressure member in a replaceable manner; A probe unit is provided above the holder unit and serves to inspect the flatness of the pressure member attached to the holder unit.

[0022] The laser beam is a square laser beam that has been homogenized by a beam shaper.

[0023] The laser beam is emitted from two or more laser modules in a superimposed manner.

[0024] The holder unit also comprises a lower plate having a through hole formed in the center so that the light-transmitting pressure member can be fitted, locked, and seated therein.

[0025] The transparent pressure member can be made of any of quartz, sapphire, fused silica glass, and diamond.

[0026] The holder unit further includes a mask plate having a vent hole formed in a center thereof for allowing a laser beam to pass therethrough, and coupled to an upper portion of the lower plate with the light-transmitting pressure member seated on the lower plate.

[0027] The through-hole of the mask plate is rectangular and has an area equal to or larger than that of the pressure surface of the light-transmitting pressure member.

[0028] The bottom surface of the lower plate has gently rounded edges on both the left and right sides.

[0029] In addition, flatness adjusting means are further provided at each edge of the lower plate to adjust the flatness of the light-transmitting pressure member by finely moving the edge of the lower plate in a vertical direction.

[0030] The flatness adjusting means includes press brackets provided on the edges of the light-transmitting pressure member and the holder unit, The press bracket further includes a vertical drive unit provided on one side of the press bracket and configured to transport the press bracket in a vertical direction in response to driving of a motor.

[0031] The vertical drive unit includes a ball screw and a motor for vertically transporting the press bracket. and a guide member for guiding the linear motion of the press bracket.

[0032] The probe unit includes a probe for measuring flatness by piercing at least one point on the upper surface of the light-transmitting pressure member; and a moving means for moving the probe horizontally or vertically. The probe bracket is also provided for fixing the probe and the moving means.

[0033] The probe is inserted into a total of four or more points including the square edge points on the upper surface of the light-transmitting pressure member for probing.

[0034] In addition, a protective film is further provided under the transparent pressure member to prevent fumes generated during laser bonding from adhering to the bottom surface of the transparent pressure member.

[0035] The protective film can be made of polytetrafluoroethylene resin (PTFE) or perfluoroalkoxy resin (PFA).

[0036] The protective film is supplied by a protective film transport unit of a reel-to-reel type that transports the rolled protective film to one side while loosening it.

[0037] The transparent pressure member includes a base material having a rectangular panel shape as a whole, The base member also includes a pressure surface that protrudes from the bottom surface of the base member and is formed flat so as to accommodate a plurality of electronic components.

[0038] In addition, at least one step portion is further provided between the base material and the pressure surface, recessed inward so that the area of the pressure surface is smaller than the area of the base material.

[0039] A laser light blocking layer is formed on the side surface of the substrate and on the bottom and side surfaces of the step portion.

[0040] The pressure surface is divided into two or more parts by a lattice groove having a certain depth.

[0041] In addition, a laser light blocking layer is further formed on the inner side and bottom of the grating grooves.

[0042] The laser light blocking layer is composed of one or a composite layer of two or more of an Inconel coating layer, a diffuse reflection processed layer, and an HR (High Reflection) coating layer.

[0043] The pressure surface has a square shape.

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

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

[0046] Also, the elastic damper layer can be made of silicon.

[0047] The laser pressure head module includes a rectangular holder unit for replaceably mounting a light-transmitting pressure member; and a pressure balancer that initializes the weights of the holder unit and the light-transmitting pressure member to zero by applying pressure to the weights of the holder unit and the light-transmitting pressure member in opposite directions while supporting the lower ends of each edge of the holder unit. The holder unit further includes a press unit that is provided above each edge of the holder unit in a non-contact state and that independently presses each edge of the holder unit with a set pressure.

[0048] The pressure balancer is composed of an air cylinder.

[0049] The pressure balancer is composed of an elastic spring.

[0050] The press units are divided and arranged one for each edge of the holder unit so that each edge can be individually pressed with a set pressure.

[0051] The press unit further includes a press bracket that grips each edge portion of the holder unit without contacting the press bracket. The press bracket also includes a pressure cylinder attached to the upper end thereof, which presses the holder units downward by a set pressure.

[0052] Furthermore, a precision air cylinder is used for the pressure cylinder, which can precisely set and adjust the pressure in kgf units.

[0053] The pressure cylinder is further provided with a pressure sensor for measuring the pressure during pressure application and constantly feeding back the measured pressure.

[0054] An ionizer unit is further provided above the holder unit for cleaning the upper surface of the light-transmitting pressure member from dust adsorption caused by static electricity.

[0055] The bonding object transport module further includes an input conveyor on which bonding objects each made of a plurality of electronic components arranged on a substrate are seated for transport; a vacuum chucking means for vacuum-chucking and fixing the bonding object supplied from the input conveyor; An output conveyor is provided on which the bonding objects that have undergone laser reflow processing are placed for transport.

[0056] Further, the input and output conveyors include a conveyor frame; a pair of wire track means provided on both sides of the upper portion of the conveyor frame; A horizontal transport means is provided on one side of the conveyor frame for moving the conveyor frame linearly in the horizontal direction.

[0057] The input and output conveyors are further provided with width adjusting means on one side of the conveyor frame so that the width of the conveyor frame can be increased or decreased to accommodate bonding objects of different sizes.

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

[0059] A vision unit is further provided on one side of the vacuum chucking means to monitor whether or not the bonding object is properly loaded.

[0060] In addition, 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 also includes a vacuum suction pad on a flat plate and a vertical drive unit for transporting the vacuum suction pad in a vertical direction.

[0062] The vacuum chucking means also includes a porous suction plate for suction-fixing the bonding object, and a horizontal conveying means for reciprocating the porous suction plate and 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 that is arranged around the central suction plate and for adsorbing the edge portion of the bottom surface of the bonding object.

[0064] The edge suction plate further has suction holes formed therein for suctioning the bottom edge of the bonding object.

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

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

[0067] The laser pressure head module also includes a multi-laser module that is arranged separately from each other and irradiates the bonding object with multiple overlapping laser beams, and a temperature sensor that is provided in the area between the multi-laser modules and senses the temperature of multiple points on the bonding object by irradiating a beam through a translucent pressure member.

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

[0069] The temperature sensor is composed of a single infrared temperature sensor, which sequentially irradiates a plurality of points on the bonding object with infrared rays.

[0070] The single infrared temperature sensor sequentially irradiates infrared rays onto a plurality of points in the periphery and center of the area where the plurality of laser beams are superimposed and irradiated.

[0071] The temperature sensor is composed of a plurality of infrared temperature sensors, which simultaneously irradiate a plurality of points on the bonding object with infrared rays.

[0072] The plurality of infrared temperature sensors simultaneously irradiate infrared rays to a plurality of points in the periphery and center of the area where the plurality of laser beams are irradiated in an overlapping manner.

[0073] Additionally, the multi-laser module further comprises a beam profiler for measuring the power and intensity of each laser beam.

[0074] Furthermore, a laser reflow method for a laser reflow apparatus that applies pressure to a bonding object, which is a rectangular substrate on which a plurality of electronic components are arranged, with a translucent pressure member and irradiates a laser beam via the pressure member to bond the electronic components to the substrate includes the steps of: (a) using the vision unit to photograph the shape of the electronic components arranged in a predetermined range located directly below the pressure surface of the translucent pressure member before the translucent pressure member presses the bonding object; (b) determining whether the photographed shape of the electronic components arranged in the predetermined range is positioned to correspond to the pressure surface; (c) when it is determined that the electronic components are positioned to correspond to the pressure surface, moving the translucent pressure member downward to apply pressure to the bonding object and irradiating the laser beam onto the bonding object via the translucent pressure member; (d) stopping the irradiation of the laser beam to move the translucent pressure member upward to release the pressure; and (e) horizontally transporting the translucent pressure member to above the predetermined range of electronic components to be reflowed next.

[0075] The step b) further comprises the steps of: b1) determining whether the photographed shape of the electronic components arranged within a predetermined range is symmetrical with respect to the center line of the pressure surface of the translucent pressure member when viewed from the side; and b2) determining that the electronic components are positioned to correspond to the pressure surface if the photographed shape of the electronic components arranged is symmetrical with respect to the center line of the pressure surface of the translucent pressure member; and adjusting the horizontal position of the translucent pressure member if the photographed shape of the electronic components is not symmetrical with respect to the pressure surface.

[0076] The laser beam is emitted from two or more laser modules in a superimposed manner.

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

[0078] Furthermore, the laser beams are emitted simultaneously from the laser modules.

[0079] The laser beams are emitted sequentially from the laser modules.

[0080] The method further includes a step of preheating the bonding object at the bottom before the step c).

[0081] In addition, the step of preheating the bonding object at the bottom maintains the surface temperature of the bonding object at less than 200°C.

[0082] In the step c), the bonding object is irradiated with a laser beam through a light-transmitting pressure member, thereby heating the surface temperature of the bonding object to 200° C. or higher.

[0083] Furthermore, a laser reflow method for a laser reflow apparatus that applies pressure to a bonding object, which is a rectangular substrate on which a plurality of electronic components are arranged, with a translucent pressure member and irradiates a laser beam through the pressure member to bond the electronic components to the substrate includes the steps of: a) moving the pressure surface of the translucent pressure member downward to contact the bonding object without applying pressure; b) irradiating the laser beam onto the bonding object through the translucent pressure member; and c) canceling the irradiation of the laser beam and moving the translucent pressure member upward.

[0084] The method further includes, after the step a), fixing the vertical movement of the light-transmitting pressure member.

[0085] The method further includes the steps of applying a predetermined constant pressure to the light-transmitting pressure member after the step a), and not fixing the vertical movement of the light-transmitting pressure member after the step b).

[0086] The method further includes the steps of fixing the vertical movement of the light-transmitting pressure member after the step a) and applying a predetermined constant pressure to the light-transmitting pressure member after the step b).

[0087] The method further includes the steps of fixing the vertical movement of the light-transmitting pressure member after the step a) and not fixing the vertical movement of the light-transmitting pressure member after the step b).

[0088] In the step b), the laser beams are emitted from two or more laser modules in a superimposed manner.

[0089] Furthermore, the laser beams are emitted simultaneously from the laser modules.

[0090] Furthermore, the laser beams are emitted sequentially from the laser modules.

[0091] Also, the method further includes a step of preheating the bonding object at the bottom before the step b).

[0092] In addition, the step of preheating the bonding object at the bottom maintains the surface temperature of the bonding object at less than 200°C. [Effects of the Invention]

[0093] The present invention as described above has the effect of significantly improving productivity through mass laser reflow processing, by simultaneously pressing and pressurizing a plurality of electronic components and irradiating a uniform laser beam to uniformly transfer heat energy to the plurality of electronic components.

[0094] Furthermore, the mask plate and the light-transmitting pressure member are designed to be replaceable to accommodate the size of the substrate and the layout shape of the electronic components, so that various substrates can all be uniformly reflow processed, which has the effect of significantly reducing the defect rate.

[0095] In addition, it is possible to prevent the laser beam leaking from the edge of the quartz that constitutes the pressure member from causing thermal damage to the peripheral substrate of the electronic component, which accelerates the deterioration of the substrate and the component, thereby significantly reducing the defect rate.

[0096] Furthermore, by configuring the holder unit to be able to independently set and adjust the pressure applied to each edge of the holder unit to which the translucent pressure member is attached, the defect rate caused by insufficient or excessive pressure acting on multiple electronic components arranged on the board is significantly reduced.

[0097] Another advantage is that a bonding object having a certain area, in which a plurality of electronic components are mounted on a substrate, can be stably transported in and out of the laser reflow treatment area at one time.

[0098] Furthermore, by monitoring the temperature imbalance in the overlapping irradiation area of the multiple laser beams, it is possible to immediately detect and repair the imbalance, thereby significantly improving the rate of defective bonding.

[0099] Furthermore, by adjusting the position of the translucent pressure member so that the electronic components are not tilted to one side and are unable to be pressed down, and pressure is not distributed evenly, the defect rate caused by uneven pressure acting on multiple electronic components arranged on the substrate can be significantly improved.

[0100] Furthermore, by precisely controlling the pressure applied by the translucent pressure member and the laser beam irradiation by the laser module in sequence using set reference values, various bonding defects, such as poor solder contact and overflow, caused by insufficient pressure or excessive pressure acting on multiple electronic components arranged on a substrate, can be significantly improved. [Brief explanation of the drawings]

[0101] [Figure 1] 1 is an exemplary diagram showing the overall configuration of a laser reflow apparatus according to the present invention;

[0102] [Figure 2] FIG. 2 is a block diagram of the configuration of FIG. 1 according to the present invention.

[0103] [Figure 3] FIG. 1 is a conceptual diagram of a single laser beam module according to an embodiment of the laser reflow apparatus of the present invention.

[0104] [Figure 4] FIG. 10 is a conceptual diagram of a dual laser beam module according to another embodiment of the laser reflow apparatus of the present invention.

[0105] [Figure 5] FIG. 10 is a configuration diagram of a dual laser beam module according to another embodiment of the laser reflow apparatus of the present invention.

[0106] [Figure 6] ~ [Figure 9] FIG. 10 is a configuration diagram of a laser optical system applicable to a dual laser beam module according to another embodiment of the laser reflow apparatus of the present invention.

[0107] [Figure 10] FIG. 2 is a perspective view of a main part that schematically illustrates the configuration of a holder unit of the laser pressure head module according to the present invention.

[0108] [Figure 11] 3 is a cross-sectional view of a main part that schematically illustrates the configuration and operating state of a holder unit of the laser pressure head module according to the present invention. FIG.

[0109] [Figure 12] 1 is a perspective view of a main part schematically showing the configuration and operating state of a probe unit of a laser pressure head module according to the present invention. FIG.

[0110] [Figure 13] 1 is a side view schematically showing the configuration and operation state of a vertical conveying section of a laser pressure head module according to an embodiment of the present invention;

[0111] [Figure 14]FIG. 10 is a perspective view of a main part, schematically illustrating the configuration and operating state of a vertical conveying unit of a laser pressure head module according to another embodiment of the present invention.

[0112] [Figure 15] FIG. 15 is a cross-sectional side view of the main part of FIG. 14 according to the present invention.

[0113] [Figure 16a] 1 is a plan view of a main part of a holder unit of a laser pressure head module according to an embodiment of the present invention, which is formed into an octagonal shape.

[0114] [Figure 16b] 10 is a plan view of a main part of a holder unit of a laser pressure head module according to another embodiment of the present invention, which is formed into a circular shape. FIG.

[0115] [Figure 17] 1A and 1B are perspective views showing the main parts of a light-transmitting pressure member of a laser pressure head module according to the present invention, in which FIG. 1A illustrates the shape of a light-transmitting pressure member having a single pressure surface according to one embodiment, and FIG. 1B illustrates the shape of a light-transmitting pressure member having divided pressure surfaces corresponding to each electronic component according to another embodiment.

[0116] [Figure 18] 4 is an operational state diagram showing a state in which the light-transmitting pressure member according to the present invention is attached to a pressure head. FIG.

[0117] [Figure 19] FIG. 19 is an enlarged view of the main part of FIG. 18 according to the present invention.

[0118] [Figure 20a] ~ [Figure 20c] 21A and 21B are schematic diagrams showing various embodiments of a translucent pressure member according to the present invention, in which FIG. 21A shows a case where the pressure surface edge is not processed, FIG. 21B shows a case where the pressure surface edge is chamfered, and FIG. 21C shows a case where the pressure surface edge is rounded.

[0119] [Figure 21] 14 is a cross-sectional side view of a main part schematically showing the overall device configuration of the laser pressure head module according to the embodiment of the present invention shown in FIG. 13. FIG.

[0120] [Figure 22] FIG. 22 is a plan view of the main part of FIG. 21 according to the present invention.

[0121] [Figure 23] 14 is an enlarged perspective view of a main part of the press unit of the laser pressurizing head module according to the embodiment of the present invention shown in FIG. 13. FIG.

[0122] [Figure 24] 1 is a perspective view illustrating the input area configuration and operational relationship of a bonding workpiece transport module according to one embodiment of the present invention; FIG.

[0123] [Figure 25] 1 is a perspective view illustrating the configuration and operational relationship of an output region of a bonding workpiece transport module according to one embodiment of the present invention; FIG.

[0124] [Figure 26a] and [Figure 26b] 26A and 26B are illustrative diagrams showing the configuration and operational relationship of the vacuum chucking means of the bonding object transport module according to the present invention, where FIG. 26A shows the configuration according to one embodiment of the porous adsorption plate, and FIG. 26B shows the configuration according to another embodiment of the porous adsorption plate.

[0125] [Figure 27] FIG. 10 is a side view schematically showing the configuration and operational relationship of a multi-laser module according to another embodiment of the present invention.

[0126] [Figure 28] 28 is an enlarged perspective view of a main part of the temperature sensor of FIG. 27 according to the present invention; FIG.

[0127] [Figure 29]29 is an enlarged plan view of a main part showing the configuration of the bonding object of the present invention shown in FIG. 28. FIG.

[0128] [Figure 30a] ~ [Figure 30e] 30a is a state diagram showing the operational relationship between the individual steps of the laser reflow method according to the present invention, in which FIG. 30a shows a state in which the light-transmitting pressing member has moved above the center line Cn+1, FIG. 30b shows a state in which the light-transmitting pressing member is pressed and irradiated with laser light at the center line Cn+1, FIG. 30c shows a state in which the light-transmitting pressing member has moved above the center line Cn+2, FIG. 30d shows a state in which the position of the light-transmitting pressing member has been corrected to the center line Cn+2', and FIG. 30e shows a state in which the light-transmitting pressing member is pressed and irradiated with laser light at the center line Cn+2'.

[0129] [Figure 31a] ~ [Figure 31d] 31a is a state diagram showing the operational relationship between the individual steps of the laser reflow method according to the present invention, in which FIG. 31a is a step in which a translucent pressure member that has previously completed reflow processing moves above a bonding object to be subjected to the next reflow processing, FIG. 31b is a step in which the pressure surface of the translucent pressure member moves downward and comes into contact with the bonding object without applying pressure, FIG. 31c is a step in which a laser beam is irradiated onto the bonding object via the translucent pressure member, and FIG. 31d is a step in which the laser beam irradiation is stopped and the translucent pressure member is moved upward.

[0130] DETAILED DESCRIPTION OF THE INVENTION

[0131] The terms used in this specification are merely used to describe particular embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises," "has," "provides," and the like specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described herein, and should be understood not to preclude the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0132] Unless otherwise defined herein, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0133] Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted as having an idealized or overly formal meaning unless expressly defined in this specification.

[0134]

[0135] The laser reflow apparatus according to the present invention will be specifically described below with reference to the accompanying FIGS. 1 and 2. FIG.

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

[0137] As shown in FIGS. 1 and 2, the laser pressure head module 300 of the laser reflow apparatus according to the present invention includes at least one multi-laser module 310, 320 for irradiating a surface light source type laser onto a bonding object 11 supported and transported on a stage 111 having a porous material or vacuum holes formed therein and having a structure for applying heat to the bottom thereof, a light-transmitting pressure member 100 that is installed independently of the laser modules 310, 320 and transmits the surface light source type laser, and a protection film 200 for protecting the light-transmitting pressure member 100 from contamination.

[0138] First, the multiple multi-laser modules 310, 320 (which may be implemented as a dual laser module in one embodiment of the present invention, for example) convert a laser beam 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, 320 may include a beam shaper (see FIG. 5) that converts a spot-shaped laser beam into a surface light source, and an optical unit (see FIGS. 5 to 9) that is disposed below the beam shaper and includes multiple lens modules mounted in a lens barrel at appropriate intervals so that the surface light source emitted from the beam shaper is irradiated onto the irradiation area of the bonding object 11.

[0139] The laser modules 310, 320 can be raised or lowered along the z-axis, moved left or right along the x-axis, or moved along the y-axis for alignment with the bonding target 11.

[0140] The laser pressure head module 300 of the laser reflow device according to the present invention is formed by separately forming the translucent pressure member 100 that presses the bonding object 11 and the laser modules 310, 320 that irradiate the bonding object 11 with a laser in the form of a surface light source. With the translucent pressure member 100 pressing down on the bonding object 11, the laser modules 310, 320 are moved to multiple irradiation positions on the bonding object 11 and then driven, thereby shortening the tact time for one bonding object 11 and speeding up the bonding operation for all multiple bonding objects 11.

[0141] At this time, the light-transmitting pressure member 100 is transported to a working position or a standby position by a light-transmitting pressure member transport unit (not shown) of a predetermined type. For example, the light-transmitting pressure member transport unit may lower or raise the light-transmitting pressure member 100, or move it left or right, and then lower or raise it.

[0142] In addition, although not shown in the drawings, the laser pressure 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-transmitting pressure member conveying unit using data input from a pressure detection sensor (not shown) and a height sensor (not shown).

[0143] The pressure sensor and height sensor may be provided on the transparent pressure member 100, the transparent pressure member conveying unit, and the stage 111 supporting the bonding object. For example, the control unit may receive data from the pressure sensor and control the transparent pressure member conveying unit so that the pressure reaches a target value, and may receive data from the height sensor and control the transparent pressure member conveying unit so that the height reaches a target value.

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

[0145] The laser pressure 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-transmitting pressure member 100, at least one pressure detection sensor that detects the pressure exerted on the light-transmitting pressure member 100, and one or more height sensors that detect the height of the light-transmitting pressure member. For example, the pressure detection sensor can be realized by at least one load cell, and the height sensor can be realized by a linear encoder.

[0146] The pressure applied to the bonding object can be adjusted through the pressure sensor, and in the case of a large area, the same pressure can be controlled to be transmitted to the bonding object through multiple actuators and multiple pressure sensors. In addition, one or more height sensors can be used to confirm the height position value at the moment the bonding object is bonded, or provide technical data for finding a more accurate bonding height value, thereby performing a function of controlling the height accurately when performing a process that requires maintaining a certain height interval.

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

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

[0149] In other words, quartz exhibits superior performance to sapphire in terms of light transmittance and heat dissipation required for bonding. However, the inventors of the present application repeatedly tested the light-transmitting pressure member 100 while developing a laser reflow device and discovered that the light-transmitting pressure member 100 made of quartz had problems with cracks and burning on the bottom surface during laser bonding, resulting in poor bonding quality. It was analyzed that this was because fumes generated during laser bonding adhere to the bottom surface of the light-transmitting pressure member 100, and the laser heat source concentrates on the areas where the fumes adhere, increasing thermal stress.

[0150] In order to prevent damage to the light-transmitting pressure member 100 made of quartz and to improve durability, a thin film coating layer may be formed on the bottom surface of the light-transmitting pressure member made of quartz. The thin film coating layer formed on the bottom surface of the light-transmitting pressure member 100 may be a dielectric coating, a SiC coating, or a metal material coating, which are common optical coatings.

[0151] As shown in FIG. 1, the laser pressure head module 300 of the laser reflow apparatus according to the present invention further includes a protective film 200 below the light-transmitting pressure member 100, which prevents fumes generated during laser bonding from adhering to the bottom surface of the light-transmitting pressure member 100, and a protective film transport unit 210 for transporting the protective film 200.

[0152] The protective film transport unit 210 may be implemented as a reel-to-reel system, which transports the rolled protective film 200 to one side while unwinding it. The protective film 200 may be implemented as a material with excellent heat resistance, such as a maximum operating temperature of 300°C or higher and a maximum continuous operating temperature of 260°C or higher. For example, the protective film 200 may be implemented as polytetrafluoroethylene resin (commonly known as Teflon resin; polytetrafluoroethylene, PTFE) or perfluoroalkoxy resin. Perfluoroalkoxy resin (Per Fluoro Alkylvinyl Virgin Ethylene Copolymer; PFA) is a product that improves the heat resistance of fluorinated ethylene propylene resin. It is a high-performance resin with a maximum continuous operating temperature of 260°C, the same as polytetrafluoroethylene resin.

[0153]

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

[0155] 3, the present invention includes a single laser module 310 according to one embodiment, which irradiates a single laser beam onto a PCB (Printed Circuit Board) substrate. According to one embodiment, the PCB substrate may 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 the laser beam is transformed into a square beam shape with a homogenized intensity.

[0157] Meanwhile, 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, and the first and second laser modules irradiate in an overlapped state at the position where an electronic component of the bonding object 11 is to be attached, thereby overlapping and irradiating a homogenized overlapped laser beam.

[0158] 4, the first laser beam is shown as a square and the second laser beam is shown as a circle, but both laser beams may be square. Also, the first laser beam and the second laser beam may be irradiated simultaneously, or the bonding object 11 may be preheated with the first laser beam and then irradiated with the second laser beam sequentially.

[0159]

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

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

[0162] In the following, except where necessary, the first laser module 310 will be mainly described among the laser modules having the same configuration to avoid redundant description.

[0163] The laser oscillator 311 generates a laser beam having a wavelength and output power within a predetermined range. For example, the laser oscillator may be a diode laser (LD) having a wavelength of 750 nm to 1200 nm, 1400 nm to 1600 nm, 1800 nm to 2200 nm, or 2500 nm to 3200 nm, a rare-earth-doped fiber laser, or a rare-earth-doped crystal laser. Alternatively, the laser oscillator may include 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 beam generated by a laser oscillator and passing through an optical fiber into a flat-topped area beam. The beam shaper 312 may 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 a surface light source form by the beam shaper, and irradiates the electronic components or irradiation area mounted on the PCB board with the laser beam. The optical lens module configures an optical system by combining multiple lenses, and the specific configuration of such an optical system will be described in detail later with reference to Figures 6 to 9.

[0166] The driving device 314 moves the distance and position of the laser module relative to the irradiation surface, and the control device 315 controls the driving device 314 to adjust the beam shape, beam area size, beam sharpness, and beam irradiation angle when the laser beam reaches the irradiation surface. The control device 315 can also comprehensively control the operation of each part of the laser module 310 in addition to the driving device 314.

[0167] Meanwhile, the laser output adjuster 370 controls the amount of power supplied to each laser module from the power supplies 317, 327, and 337 corresponding to each laser module 310, 320, and 330 according to a program received via a user interface or a preset program. The laser output adjuster 370 receives information on the reflow status of each component, each region, or the entire reflow process on the irradiation surface from one or more camera modules 350 and controls each power supply 317, 327, and 337 based on the information. Alternatively, the control information from the laser output adjuster 370 can be transmitted to the controllers 315, 325, and 335 of each laser module 310, 320, and 330, and each controller 315, 325, and 335 can provide a feedback signal for controlling the corresponding power supply 317. Also, unlike FIG. 6, power can be distributed to each laser module through a single power supply, in which case the power supply must be controlled by the laser output adjuster 370.

[0168] When the laser superposition mode is implemented, the laser output adjusting unit 370 controls each laser module and the power supply units 317, 327, 337 so that the laser beams from each laser module 310, 320, 330 have the required beam shape, beam area size, beam definition, and beam irradiation angle. The laser superposition mode is applied not only to a case where the first laser module 310 is used to preheat the area up to the periphery of the position to be debonded and the second laser module 320 is used to further heat a narrower area to be reflowed, but also to a case where each laser module is controlled to have the required temperature profile by appropriately distributing the preheating function and the additional heating function among the first, second, and third laser modules 310, 320, ... 330.

[0169] On the other hand, when one laser light source is divided and input to each laser module, the laser output adjuster 370 can be provided with a function to simultaneously adjust the output and phase of each divided laser beam. In this case, the phase can be controlled to induce destructive interference between each laser beam, thereby significantly improving beam flatness and further improving energy efficiency.

[0170] On the other hand, when realizing the multiple-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 some or all of the laser beams from each laser module are different. Even in this case, when one laser light source is distributed and input to each laser module, the laser output adjustment unit 370 may be provided with a function to simultaneously adjust the output and phase of each distributed laser beam.

[0171] This function allows for bonding or removal of bonding between electronic components and a substrate within the irradiation area by adjusting the size and power of the laser beam. In particular, when removing damaged electronic components on a substrate, minimizing the area of the laser beam to the corresponding electronic component area minimizes the application of heat from the laser beam to normal electronic components from other adjacent electronic components on the substrate. Therefore, it is possible to remove only the damaged electronic components to be removed.

[0172] Meanwhile, when multiple laser modules emit laser beams having different wavelengths, the laser modules can be configured with individual laser modules having wavelengths that are well absorbed by multiple material layers (e.g., EMC layer, silicon layer, solder layer) included in the electronic component. Therefore, the laser debonding apparatus according to the present invention can perform an optimized bonding or detaching process by selectively and differently increasing the temperature of the electronic component and the temperature of an intermediate bonding material, such as a solder, which connects the printed circuit board and the electronic component electrodes. Specifically, the laser beams can penetrate both the EMC mold layer and silicon layer of the electronic component so that all of the energy of each laser beam is absorbed by the solder layer, or the laser beams can heat the surface of the electronic component without passing through the EMC mold layer, thereby conducting heat to the bonding portion below the electronic component.

[0173] By utilizing the above functions, a certain area of a substrate including an electronic component area to be reflowed and its surroundings is preheated to a predetermined preheat temperature by at least one first laser beam, and then the temperature of the electronic component area to be reflowed is selectively heated to a reflow temperature at which the solder melts by at least one second laser beam. By utilizing this selective heating effect, the present invention can be used, for example, as a rework device that efficiently removes electronic components from a substrate.

[0174]

[0175] 6 to 9 are diagrams illustrating the configuration of a laser optical system that can be applied to a single laser beam or 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. A laser beam emitted from a beam transmission optical fiber 410 is focused through a convex lens 420 and enters a 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 a concave lens 440 and irradiates the image plane S with the expanded surface light source A2.

[0177]

[0178] FIG. 7 is a diagram showing the configuration 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 enlarged to a predetermined size via the concave lens 440 to become the surface light source B2 that is irradiated onto the first image plane S1. If it is desired to further enlarge this surface light source B2 for use, the additional enlargement may make the boundary at the edge of the surface light source B2 even more unclear. Therefore, in order to obtain irradiated light with a clear edge even when the final irradiation surface is the second image plane S2, a mask 450 is provided on the first image plane S1 to trim the edge.

[0180] The surface light source that passes through the mask 450 is reduced (or enlarged) to the desired size as it passes through a zoom lens module 460 consisting of a combination of one or more convex and concave lenses, forming a square illumination light B3 on a second imaging plane S2 on which electronic components are arranged.

[0181]

[0182] FIG. 10 is a configuration diagram of a laser optical system according to another embodiment of the present invention.

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

[0184] Here, the cylindrical lens is a cylinder cut longitudinally, and has the function of expanding or contracting the laser beam depending on the way each lens is arranged in the vertical direction, and adjusts the laser beam in the x-axis or y-axis direction depending on the way the lenses on the surface on which the cylindrical lens is arranged are arranged in the x-axis or y-axis directions.

[0185] Next, the surface light source C3 is enlarged (or reduced) to the desired size as it passes through a zoom lens module 460 consisting of a combination of one or more convex and concave lenses, and forms rectangular illumination light C4 on a second imaging plane S2 on which electronic components are arranged.

[0186]

[0187] FIG. 10 is a configuration diagram of a laser optical system according to another embodiment of the present invention.

[0188] It will be understood that the optical system of Figure 9 is the optical system of Figure 8 to which a configuration for applying a mask to trim the edges of the laser beam has been added, and that a final surface light source D5 having sharper edges than in the case of Figure 8 can be obtained.

[0189]

[0190] FIG. 10 is a perspective view of a main part that schematically shows the configuration of a holder unit of the laser pressure 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, transparent pressure member 100 is fitted and seated, and a mask plate 520 that fits and engages with the upper part of the transparent pressure member 100.

[0192] Furthermore, square through-holes 510a and 520a are formed in the center of the lower plate 510 and the mask plate 520, respectively, and since the translucent pressure member 100 is fitted and seated on the lower plate 510, 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] Meanwhile, in the above-mentioned state, the mask plate 520 is fitted and coupled to the upper surface of the light-transmitting pressure member 100, and the mounting is completed in a state where the central portion of the upper surface of the light-transmitting pressure member 100 is 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, which schematically shows the configuration and operating state of a holder unit of the laser pressure head module of the present invention.

[0196] Referring to FIG. 11, when the light-transmitting pressure member is mounted between the lower plate and the mask plate and a laser is irradiated from the multi-beam laser modules 310 and 320 positioned above, it can be seen 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] In this case, the left and right edges of the bottom surface of the lower plate 510 are gently rounded so that when the protective film 200 located below the translucent pressure member 100 is pressed down as the translucent pressure member 100 moves downward, the protective film 200 will not be torn or damaged by the rounded edges of the lower plate 510.

[0198] Furthermore, as described above, the protective film 200 is pulled and wound up by the protective film conveying units 210 arranged on both the left and right sides of the protective film 200, and even at this time, since the left and right edges 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 translucent pressure member 100 simultaneously presses a plurality of electronic components arranged on the substrate, which is the bonding object 11, to a certain depth, while the multi-laser modules 310, 320 positioned above it irradiate laser beams, thereby melting the solder located below the electronic components of the bonding object 11 and causing the laser reflow process to proceed.

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

[0201] In this case, if the superimposed laser beam is irradiated onto the peripheral substrate portion outside the electronic component, the peripheral substrate portion may be damaged by the thermal energy of the laser beam, and therefore, it is necessary to limit the irradiation to only the electronic component of the bonding object 11. For this reason, in order to accurately pressurize and laser reflow only the electronic component 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-transmitting pressing member 100 taking into consideration the transmission path of the laser beam, the overlapping area, etc.

[0202]

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

[0204] The main feature of the present invention is that the mask plate 520 and the light-transmitting pressure member 100 are configured to be interchangeable so as to accommodate various substrate sizes. Therefore, the light-transmitting pressure member 100 and the mask plate 520 are configured to be interchangeable with different ones depending on whether substrates of different sizes are to be processed or the shape and area of the electronic components arranged on the substrate. In this case, the worker selects and replaces the light-transmitting pressure member 100 and the mask plate 520 of an appropriate size from those prepared in advance so as to have pressure surfaces of various different sizes, and then measures the flatness by piercing and probing the edge portion of the upper surface of the light-transmitting pressure member 100 with a bar-shaped probe unit 600 shown in FIG. 12.

[0205] The probe unit 600 is composed of a needle-shaped probe 610, a probe carrier 620 that carries the probe horizontally or vertically, and a probe bracket 630 that supports the probe and the carrier.

[0206] Therefore, when an operator replaces the mask plate 520 with a light-transmitting pressure member 100 of another size in order to process a substrate of a different size, the probe 610 is transported horizontally or vertically, and, as an example, the flatness of the light-transmitting pressure member 100 can be measured by piercing and probing four or more points (indicated by X) on the edge portion of the top surface of the light-transmitting pressure member 100 in order.

[0207]

[0208] FIG. 13 is a side view schematically showing the configuration and operation state of a vertical conveying section of a laser pressure head module according to an embodiment of the present invention.

[0209] The configuration and operation of the vertical conveying section of the laser pressure head module will be described below with reference to FIG.

[0210] According to one embodiment, the vertical conveying unit configuration can be configured with press brackets 720 provided at four locations on each edge of the light-transmitting pressurizing member 100 and the holder unit 500, a pressurizing cylinder 730 provided on the top of the press bracket, and a vertical driving unit that applies a driving force to the press bracket 720 in the vertical direction, that is, as an example, a ball screw 750, a motor 760, and a guide member 770 that guides the linear motion of the press bracket 720.

[0211] Therefore, before the bonding object 11 consisting of a substrate and an electronic component is placed below the light-transmitting pressing member 100, the light-transmitting pressing member 100 and the holder unit 500 are transported upward by the motor 760 of the vertical transport section, and after the bonding object 11 is placed, the light-transmitting pressing member 100 and the holder unit 500 are transported downward again by the motor 760 and wait for pressure to be applied. Thereafter, the pressure cylinder 730 operates to cause the light-transmitting pressing member 100 to press the bonding object 11 vacuum-attracted on the electrostatic chuck 940, thereby applying pressure.

[0212] Meanwhile, a heating block 942 for preheating the bonding object 11 to a constant temperature is provided below the electrostatic chuck 940, so that the bonding object 11 continues to be preheated while being transported for laser reflow processing while seated on the electrostatic chuck 940. For example, the temperature to which the bonding object 11 is preheated can be set to less than 200° C., and it is desirable to set the temperature to a level that does not cause thermal damage to the substrate, etc., due to the preheating.

[0213] On the other hand, as shown in FIG. 12, if the probe unit 600 measures the flatness of the light-transmitting pressure member 100 and determines that the light-transmitting pressure member 100 is tilted to either side, i.e., is not flat, the vertical conveying unit is finely driven to convey the holder unit 500 upward or downward, thereby adjusting the flatness of the light-transmitting pressure member 100.

[0214] More specifically, if the result of measuring the flatness of the translucent pressure member 100 by the probe unit 600 indicates that one of the four edges on the upper surface of the translucent pressure member 100 is tilted to one side relative to the other edges and is positioned at a low point, then, as an example, the motor 760 of the edge portion positioned at the low point is activated to slightly lift the edge of the holder unit 500 upward, thereby adjusting the overall flatness of the translucent pressure member 100.

[0215] In this case, by installing, for example, an absolute encoder in the motor 760, it is possible to maintain the absolute position value of each edge portion of the holder unit 500 at all times regardless of the power supply state, and it is desirable that the flatness adjustment process of the above-mentioned transparent pressure member (100) be automated by setting the control unit.

[0216]

[0217] FIG. 14 is a perspective view of the main part, which schematically shows the configuration and operation state of a vertical conveying part of a laser pressure 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.

[0218] Hereinafter, the detailed configuration of the laser pressure head module of the present invention and the operational relationship between pressure and laser beam irradiation will be described in detail in one embodiment with reference to the drawings.

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

[0220] The holder unit 500 may be formed to have a circular or polygonal shape (see FIGS. 16a and 16b), but in the following description, it will be assumed that the holder unit 500 has an octagonal shape in FIGS. 14 and 15.

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

[0222] In this case, an imaginary triangle connecting the fine points of the holder unit 500 can form an equilateral triangle, and it is desirable that the center of gravity G of the imaginary triangle and the center of gravity G of the light-transmitting pressure member 100 coincide with each other.

[0223] The reason for designing three axial connection points P1, P2, and P3 around the edge of the holder unit 500 is that the connection of the axial connection points P1, P2, and P3 by condensing two press units is stable. Because a triangular structure cannot be formed (i.e., when connecting two points, a line segment is formed, but an area cannot be formed), in other words, in order to minimize the number of condensation points that require flatness control while also forming stable axial connection points of a virtual triangle, the three axial connection points P1, P2, and P3 are configured precisely symmetrically on the holder unit 500.

[0224]

[0225] 15, the press unit 700 includes a press bracket 720 having a certain height and shape, a pressure cylinder 730 attached to the upper end of the press bracket and pressing the holder unit 500 downward by a set pressure, and a bearing joint 780 having one end connected to a cylinder rod 731 of the press cylinder 730 and the other end rotatably connected to one of the fine shaft connection points P1, P2, and P3 of the holder unit 500. The pressure cylinder may be a precision pneumatic cylinder (hereinafter referred to as a pneumatic cylinder) capable of precisely setting and adjusting the pressure in kgf units.

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

[0227] The pressure sensor 740 can be realized as a load cell, for example, and when the cylinder rod of each pressure cylinder 730 is pulled out to pressurize each axial connection point of the holder unit 500, it constantly measures the pressure, checks whether a pressure exceeding the appropriate pressure is being applied, and feeds back the result to a control unit (not shown).

[0228] Meanwhile, a joint fastening portion 510 is further provided at each of the three shaft engagement points of the holder unit 500, and each joint fastening portion 510 is rotatably connected to the bearing joint 780 by a pivot hinge.

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

[0230] Therefore, by adjusting the extension length of the cylinder rod 731 of each pressure cylinder 730 to be different, the holder unit 500 can be tilted, and the pressure can be precisely adjusted by adjusting the contact height of the holder unit 500.

[0231] In addition, the end of the joint fastening portion 510 is engaged and seated by a stopper 790 provided at the lower end of the press bracket 720, thereby offsetting the weight of the holder unit 500 acting downward by crossing the stopper 790 and maintaining flatness when the holder unit 500 is transported vertically.

[0232] Furthermore, a vertical conveyor is further provided on one side of the press bracket 720 for vertically raising and lowering the press bracket.

[0233] According to one embodiment, the vertical conveying unit configuration can be composed of press brackets 720 provided at three axial engagement points of the light-transmitting pressurizing member 100 and the holder unit 500, a pressurizing cylinder 730 provided on the top 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, it can be understood that when the holder unit 500 is moved downward, the translucent pressure member 100 attached to the holder unit 500 also moves downward, pressing down and applying pressure to the electronic component 11 located below it.

[0235] In addition, the flatness of the holder unit 500 may be distorted due to vibrations that occur during the reflow process or when the transparent pressure member 100 is replaced, so the transparent pressure member 100 is replaced periodically or periodically. After that, it is preferable to initialize the flatness to zero and set it.

[0236]

[0237] FIG. 16a is a plan view of a main part of a holder unit of a laser pressure head module according to an embodiment of the present invention, which is formed into an octagonal shape.

[0238] First, the shape of the holder unit according to the present invention may be a polygon, or may be a triangle shape connecting three axial connection points P1, P2, and P3. More specifically, for geometric symmetry, the holder unit may be formed into an equilateral triangle by forming imaginary lines connecting each of the three axial connection points P1, P2, and P3 with the center of gravity G to be equal in length.

[0239] Also, FIG. 16a shows an embodiment in which a rectangular translucent pressure member must be seated and accommodated inside the polygonal holder unit, and the holder unit is configured to have an octagonal shape to provide an area larger than the translucent pressure member so as to be able to adequately accommodate the rectangular translucent pressure member.

[0240] Therefore, the holder unit of the present invention is not limited to the octagonal shape shown in FIG. 16a, but can be realized in various polygonal shapes such as a triangle, a square, or an octagon that can have a virtual triangle connecting the three axial connection points P1, P2, and P3 in a plan view.

[0241]

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

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

[0244] Therefore, even if the holder unit is formed in a circular shape as shown in Figure 16(b), the lengths of the imaginary lines connecting each of the three axial connection points P1, P2, and P3 around the edge of the holder unit to the central center of gravity G are equal, making the holder unit geometrically symmetrical and allowing precise pressure and control of each axial connection point while maintaining high flatness using only the minimum three axial connection points P1, P2, and P3.

[0245]

[0246] Therefore, as explained above, the pressure head of the present invention uses the light-transmitting pressure member 100 having a certain area to simultaneously press and apply pressure to a plurality of electronic components 11 while irradiating them with the light-transmitting laser beam, thereby enabling reflow processing all at once, which has the effect of significantly improving accuracy and productivity compared to the conventional method in which a small light-transmitting pressure member is raised for each electronic component and pressure is applied by its own weight.

[0247] Furthermore, the pressure cylinder 730 is a positive hole cylinder that can precisely adjust the pressure in kgf units, so that the pressure can be precisely adjusted. This allows the operator to set different pressures on the pressure cylinder 730 depending on various variables such as the bending state of the FPCB board, making it easier to adjust the balance of pressure applied to the electronic component 11 placed below the large-area light-transmitting pressure member 100 of the present invention than in the past.

[0248] Meanwhile, when a pressure different from the set pressure is applied to each pressure cylinder 730 and is greater than the set pressure, the pressure sensor 740 connected to the end of the cylinder rod 731 of the pressure cylinder 730 detects this and feeds back to the control unit (not shown).

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

[0250]

[0251] 14 to 16a and 16b, the holder unit 500, the light-transmitting pressure member 100, and the press unit 700 can be installed in the light-transmitting pressure member conveying section 140 and the support section 150 shown in FIG. 2. The light-transmitting pressure member conveying section 140 can be realized as a vertical conveying means (for example, a motor and a ball screw device) so as to be capable of vertical conveyance in the up and down direction, and the support section 150 can be realized as a gentree device, for example.

[0252] Therefore, when the bonding target 11, which is an electronic component and a substrate, is inserted, the holder unit 500, the light-transmitting pressure member 100, and the press unit 700 move vertically upward so that the bonding target 11 can be inserted to a position directly below the light-transmitting pressure member 100. After the bonding target 100 has been inserted to a position directly below the pressure member 100, the holder unit 500, the light-transmitting pressure member 100, and the press unit 700 move vertically downward again to a position close to the bonding target 11, and are positioned in an atmospheric condition for pressurization.

[0253]

[0254] 1A is a perspective view of a main part of a light-transmitting pressure member of a laser pressure head module according to the present invention, illustrating the shape of a light-transmitting pressure member having a single pressure surface according to one embodiment, and FIG. 1B is a perspective view of a light-transmitting pressure member having pressure surfaces divided to correspond to each electronic component according to another embodiment.

[0255] 17a and 17b, the structure of a light-transmitting pressure member 100 according to one embodiment of the present invention will be described. As shown in Fig. 17a, the light-transmitting pressure member 100 of the present invention has a rectangular plate-shaped substrate 101 on which a pressure surface 102 of a certain area is protruded. The area of the pressure surface 102 is preferably designed to correspond to the area of the bonding object 11 to be laser reflow-treated at one time, taking into consideration the area of the bonding object 11 to be laser reflow-treated at one time.

[0256] In this case, the area of the pressure surface 102 is formed to be smaller than the area of the base material 101, and there is at least one step portion 101a around the pressure surface 102. In addition, a laser light blocking layer 103 and a shading mark are further formed on the side surface of the base material 101 and the bottom and side surfaces of the step portion 101a, excluding the pressure surface 102, to block the laser light beam.

[0257] Meanwhile, referring to Figure 17b, the structure of a transparent pressing member 100 according to another embodiment of the laser pressing head module of the present invention shows that while a single pressing surface 102 is formed in Figure 17a, in Figure 17b the pressing surface 102 is divided into a grid pattern corresponding to the area of each electronic component in order to contact and press each of the multiple electronic components included in the bonding target 11. For this reason, in the structure shown in Figure 17b, the pressing surface 102 needs to be designed and processed so as to accurately correspond to the area occupied by each electronic component to be laser reflow processed.

[0258] In this case, as shown in FIG. 17b, a laser light blocking layer 103 (shown in shading) is further formed on the side surfaces of the substrate 101 other than the multiple pressure surfaces 102 divided into a grid pattern, and on the bottom and side surfaces of the step portion 101a.

[0259] The laser light-blocking layer 103 can be formed of various types of special coating layers that generally absorb or reflect light, and can be implemented as a composite layer of one or more of an Inconel coating layer that absorbs laser beams, a diffuse reflection 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 precisely irradiated only onto the electronic components of the bonding target 11 through the pressure surface 102 of the light-transmitting pressure member 100, thereby preventing thermal damage to the board and resulting damage caused by the laser beam irradiating portions of the printed circuit board (PCB) around the electronic components.

[0260]

[0261] FIG. 18 is an operational state diagram showing a state in which the light-transmitting pressure member according to the present invention is attached to a pressure head, and FIG. 19 is an enlarged view of the essential parts of FIG.

[0262] 18 and 19, the light-transmitting pressure member 100 of the present invention has a structure in which, as described above, a pressure surface 102 having an area smaller than that of a rectangular base material 101 is formed to protrude from the bottom surface of the base material. At this time, at least one step portion 131a is formed between the base material 101 and the pressure surface 102, and as shown in Fig. 15, the step portion 101a is used to attach the light-transmitting pressure member 100 to a holder unit 500 of a reflow soldering machine.

[0263] Meanwhile, a silicone damper layer 104 may be further formed on the pressure surface 102. Generally, electronic components arranged on a printed circuit board (PCB) constituting the bonding object 11 are not completely flat but have their own curvature due to the characteristics of the ductile circuit board. As a result, each electronic component can be understood as being arranged at different heights rather than at the same height on a horizontal line along the curved surface of the ductile circuit board.

[0264] At this time, when the pressure surface 102 of the translucent pressure member 100 simultaneously presses electronic components located at different heights on the bending surface of the ductile circuit board for the bonding process, the electronic components located at a relatively higher position will receive a greater pressure than the electronic components located at a lower position. As a result, the solder located below the electronic components located at a higher position will not be able to reflow normally due to the excessive pressure, which may result in poor bonding.

[0265] For this reason, a silicon damper layer 104, which is a light-transmitting elastic material according to an embodiment of the present invention, is further formed on the pressure surface 102, so that even if excessive pressure acts on the electronic components located above, the silicon damper layer 104 performs a damping function of absorbing a certain amount of the excessive pressure.

[0266] Meanwhile, when the transparent pressing member 100 presses and applies pressure to the electronic component, a laser beam is irradiated from the first or second laser module 310, 320 located above the transparent pressing member 100, and the laser beam is irradiated to the electronic component through the transparent pressing member 100, thereby transferring thermal energy for reflow.

[0267] Referring to FIG. 19, when a laser beam is irradiated through the translucent pressure member 100, the laser beam blocking layer 103 (shown in shading) is formed on the side surface of the base material 101 and the bottom and side surfaces of the step portion 101a, and as a result, the laser beam is blocked from leaking to all parts other than the pressure surface 102.

[0268] Furthermore, for uniform laser reflow processing, the present invention presents the shape and protrusion height of the pressure surface 102 as major considerations when designing the light-transmitting pressure member 100. For example, as shown in Fig. 17a, if the pressure surface 102 is formed in a rectangular structure rather than a square structure, it is predictable that the thermal energy of the laser beam on the long side of the rectangle will be lost more quickly because the side surface area of the long side is larger than that of the short side.

[0269] When this deterioration phenomenon occurs, thermal energy is not uniformly transferred to the multiple electronic components that are placed under the pressure surface 102 and are being pressed, which increases the likelihood of bonding failure for electronic components that are either lower or higher than the appropriate bonding temperature. In a preferred embodiment, the bottom of the pressure surface 102 is designed to have a square structure, which allows heat to escape uniformly through the sides of the pressure surface 102 in all directions.

[0270] Furthermore, if the protruding height h of the side surface of the pressure surface 102 is formed too high, there is a risk that a large amount of heat will escape through the side surface of the step portion 101a, so it is most desirable to minimize the protruding height h of the pressure surface 102 or the depth of the grating grooves 102a recessed between the divided pressure surfaces 102 to within a few mm.

[0271]

[0272] On the other hand, Figures 20a to 20c are schematic diagrams showing various embodiments of the translucent pressure member according to the present invention, in which Figure 20a shows a case where the pressure surface edge is not processed, Figure 20b shows a case where the pressure surface edge is chamfered, and Figure 20c shows a case where the pressure surface edge is rounded.

[0273] 20a, 20b, and 20c, it has been described that the protective film 200 is provided below the transparent pressure member 100 of the present invention to prevent the adsorption of fumes as shown in Fig. 2. When the transparent pressure member 100 is moved downward to pressurize the bonding object 11 as shown in Fig. 20a, the protective film 200 is also pressed by the transparent pressure member 100, and it can be seen that the protective film 200 contacts both edges of the pressing surface 132.

[0274] However, as mentioned above, repeated contact of the protective film 200 with both edges of the pressure surface 102 can eventually lead to problems such as the protective film 200 being torn or damaged.

[0275] Therefore, to prevent this clogging, both ends of the pressure surface 102 are chamfered as shown in Fig. 20b or as shown in Fig. 20c. By rounding both ends in this way, an additional consideration is presented when designing the light-transmitting pressure member 100.

[0276]

[0277] 21 is a cross-sectional side view of the essential parts, schematically showing the overall device configuration of the laser pressure head module according to one embodiment of FIG. 13, FIG. 22 is a plan view of the essential parts of FIG. 21, and FIG. 23 is an enlarged oblique view of the essential parts of the press unit of the laser pressure head module according to one embodiment of FIG. 13.

[0278] Hereinafter, the detailed configuration of the laser pressure head module of the present invention and the operational relationship between pressure and laser beam irradiation will be described in detail in one embodiment with reference to the drawings.

[0279] 21 and 22, the pressure head of the present invention is provided with a light-transmitting pressure member 100 for transmitting the laser beam irradiated from the laser sources 310 and 320 while pressing and applying pressure to the electronic component 11, which is the bonding target. The light-transmitting pressure member 100 is attached to a plate-shaped holder unit 500 while being hung in a through-hole formed in the center of the holder unit 500. As a result, when the holder unit 500 is moved downward, the light-transmitting pressure member 100 attached to the holder unit also moves downward, thereby applying pressure to the electronic component 11 located below.

[0280] Additionally, press units 700 are disposed adjacent to each edge of the holder unit 500 in a non-contact manner. First, the holder unit 500 is supported at its lower part by a pressure balancer 710, which acts as a buffer to apply pressure in the opposite direction to offset the weight of the light-transmitting pressure member 100 and the holder unit 500. As a component that fulfills this role, for example, an air cylinder or an elastic spring can be used.

[0281] Therefore, after the pressure balancer 710 offsets the basic weight of the translucent pressure member 100 and the holder unit 500 to a zero (0) value, the translucent pressure member 100 is placed in a standby state for applying pressure.

[0282]

[0283] Meanwhile, referring to FIG. 23, a closer look at the other components of the press unit 700 reveals that it comprises a press bracket 720 shaped to enclose each edge portion of the holder unit 500 in a non-contact manner, pressure cylinders 730a, 730b, 730c, and 730d fixedly installed on the upper ends of the press brackets, and pressure sensors 740 installed on the ends of the cylinder rods of the pressure cylinders 730a, 730b, 730c, and 730d.

[0284] In this case, the pressure sensor 740 can be realized as a load cell, for example, and constantly measures the pressure when the cylinder rods of the pressure cylinders 730a, 730b, 730c, and 730d are pulled out and pressurize each edge of the holder unit 500, checking whether a pressure exceeding the appropriate pressure has been applied and providing feedback.

[0285] Therefore, as explained above, the pressure head of the present invention uses the light-transmitting pressure member 100 having a certain area to simultaneously press and apply pressure to a plurality of electronic components 11 while irradiating them with the light-transmitting laser beam, thereby enabling the reflow treatment to be carried out all at once, which has the effect of significantly improving productivity compared to the conventional method in which a small light-transmitting pressure member is placed on each electronic component and pressure is applied by its own weight.

[0286] For this reason, according to the present invention, pressure cylinders 730a, 730b, 730c, and 730d are separately installed so that the pressure can be independently set for each corner of the holder unit 500, thereby enabling adjustment of the pressure over a large area. Also, the pressure cylinders 730a, 730b, 730c, and 730d can be implemented using precision pneumatic cylinders (hereinafter referred to as "hole cylinders"), as an example, that can precisely adjust the pressure in kgf units. As a result, an operator can easily adjust the planar pressure balance of the large-area light-transmitting pressure member 100 of the present invention compared to the conventional method by adjusting the set pressures of the pressure cylinders 730a, 730b, 730c, and 730d differently depending on various variables such as the bending state of the PCB board.

[0287] Meanwhile, when a pressure higher than the set pressure is applied to each of the pressure cylinders 730a, 730b, 730c, and 730d, the pressure sensor 740 connected to the end of the cylinder rod 731 of each of the pressure cylinders 730a, 730b, 730c, and 730d detects this and feeds back to the control unit (not shown). Therefore, when a pressure higher than a certain level is detected, the control unit performs an auto-balancing process to adjust the pressure to the set pressure value or issues an alarm, allowing an operator to easily manually adjust the set pressure of each of the pressure cylinders 730a, 730b, 730c, and 730d as necessary.

[0288] 21 to 23, the holder unit 500, the light-transmitting pressure member 100, and the press unit 700 are provided in the light-transmitting pressure member conveying section 140 and the support section 150 shown in Fig. 2. The light-transmitting pressure member conveying section 140 can be realized, for example, by a vertical conveying means (for example, a motor and a ball screw device) so as to be capable of vertical conveyance in the up and down direction, and the support section 150 can be realized, for example, by a gentree device.

[0289] Therefore, when the bonding object 11, which is an electronic component and a substrate, is inserted, the holder unit 500, the light-transmitting pressure member 100, and the press unit 700 move vertically upward so that the bonding object 11 can be inserted to a position directly below the light-transmitting pressure member 100. After the bonding object 100 has been inserted to a position directly below the pressure member 100, the holder unit 500, the light-transmitting pressure member 100, and the press unit 700 move vertically downward again to a position close to the bonding object 11, and are positioned in an atmospheric condition for pressurization.

[0290]

[0291] 21 and 22, an ionizer 800 is further provided above the holder unit 500 to remove contamination caused by particles such as dust that settle on the upper surface of the light-transmitting pressure member. The light-transmitting pressure member 100 may be made of quartz, for example. Even if the space in which the process according to the present invention is performed is a clean room environment, some particles may settle and accumulate, causing damage such as burning of the particles when irradiated with a laser beam.

[0292] Therefore, if the burning of the particles is repeated for a long period of time, the upper surface of the light-transmitting pressurizing member 100 will become increasingly discolored, which may eventually cause damage such as cracks to the light-transmitting pressurizing member 100. Therefore, the ionizer 800 prevents the particles from adsorbing to the upper surface of the light-transmitting pressurizing member 100 by, for example, eliminating static electricity generated on the upper surface of the light-transmitting pressurizing member 100 as needed.

[0293]

[0294] Figure 24 is an oblique view of one embodiment of the input area configuration and operational relationship of the bonding object transport module of the present invention. Below, with reference to Figure 24, the mechanical configuration and operational relationship of the input area (carry-in area) of the bonding object of the present invention will be examined as follows.

[0295] The input area configuration includes an input conveyor 910 for loading a bonding object (e.g., a PCB with multiple electronic components mounted thereon) of a certain area for the laser reflow process. JPEG0007720672000001.jpg1117, a pair of wire-shaped conveyor frames 912 are provided on both sides of the upper side of the conveyor frame 912, each having a bent shape for conveying bonding objects 11. Track means 911 is provided, and the wire track means 911 is connected to the rotation shaft of a track drive motor 913. Also, a width adjustment motor 915 is provided on one side of the conveyor frame 912 to expand or reduce the width of the input conveyor 910 to accommodate bonding objects 11 of different sizes.

[0296] Furthermore, since a horizontal transport unit 920 is attached to one end of the conveyor frame 912, as the horizontal transport unit 920 moves horizontally, the conveyor frame 912 also moves horizontally.

[0297] Meanwhile, a preheating stage 914 is provided above the conveyor frame 912, and while the bonding object 11 transported by the wire track means 911 remains 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 (e.g., 150°C), so that the temperature can be quickly and stably raised to the desired solder melting temperature (e.g., 250°C) by irradiation of the laser beam during laser reflow.

[0298] Meanwhile, in order for the input conveyor 910 to horizontally transport the bonding workpiece 11 while it is being preheated on the preheating stage 914 and to be introduced into the reflow treatment area, the bonding workpiece 11 must be accurately transferred onto the vacuum chuck 940. 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 suctioning the bonding workpiece, a cylinder 932 for vertically driving the vacuum suction pad, 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 actuation of the cylinder 932. Thereafter, when the bonding target 11 is positioned below the vacuum suction pad 931, the vacuum suction pad 931 is moved downward to pick up the bonding target 11 and then transported upward again. Thereafter, when the input conveyor 910 is transported horizontally to its original position and moves out from under the vacuum suction pad 931, the vacuum suction pad 931 is again moved downward to place the bonding target 11 on the vacuum chuck 940, and the operation is repeated.

[0300] Thereafter, a horizontal conveying means, for example, a linear motor 941, is provided below the vacuum chuck 940, and the operation of the linear motor 941 moves the vacuum chuck 940 and the bonding object 11 together to the laser reflow processing area.

[0301] In addition, a vision unit 934 is further provided on one side of the vacuum chuck 940, which constantly monitors whether the bonding object 11 is correctly seated and aligned on the vacuum chuck in the input area, and whether the loading is normal.

[0302]

[0303] 25 is a perspective view showing the configuration and operational relationship of the output area of the bonding object transport module according to the present invention. The configuration and operational relationship of the mechanical parts of the output area (export area) of the bonding object according to the present invention will be examined below with reference to FIG.

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

[0305] Therefore, when the bonding object 11 after laser reflow processing is transported to the output area (export area) while seated on the vacuum chuck 940, the picker unit 970 adsorbs the bonding object 11 onto the vacuum chuck 940 in the reverse order of the transport-in procedure and transfers it to the output conveyor 950, after which the output conveyor 950 transports the bonding object 11 horizontally and then unloads it outside the device via the wire track means 951.

[0306]

[0307] Figures 26a and 26b are illustrative diagrams showing the configuration and operating relationship of the vacuum chucking means of the bonding object transport module of the present invention, where 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 embodiment of the porous adsorption plate.

[0308] 26a, a vacuum chuck 940 according to an embodiment of the present invention has an upper surface made up of a plurality of porous suction plates, which are used to suction the central portion of the bottom surface of the bonding object 11. The porous suction plates are divided into a rectangular central suction plate 943 and edge suction plates 944 that are arranged to wrap around the central suction plate and to suction the edge portion of the bottom surface of the bonding object 11.

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

[0310] Furthermore, referring to the attached side cross-sectional view, the central suction plate 943 and the edge suction plates 944 are separated from each other at a predetermined interval, and a suction plate lifting unit 980 is installed below the central suction plate 943. Therefore, when the central suction plate 943 is required, that is, in the configuration of the above-mentioned embodiment, another embodiment configuration may be provided in which the picker units 930 and 970 are omitted. That is, the central suction plate 943 can immediately receive the bonding workpiece 11 from the input conveyor 910. In this case, the object of the present invention can be sufficiently achieved even if the central suction plate 943 is raised upward to immediately receive the bonding workpiece 11 from the input conveyor 910, and then the central suction plate 943 immediately picks up the bonding workpiece 11 from the wire track means 911 of the input conveyor 910 and then descends again.

[0311] In addition, a heating block 942 can be further installed directly below the central suction plate 943, and the heating block 942, like the preheating stage 914 of the input conveyor 910, serves to preheat the bonding object 11 to a predetermined temperature while the bonding object is being carried in before being subjected to laser reflow processing.

[0312]

[0313] Meanwhile, Figure 26b shows the configuration and operational relationship of another embodiment of a porous suction plate according to the present invention. The difference from the configuration of the embodiment shown in Figure 26a is that the edge suction plate 945 is made of aluminum, not the same porous material as the central suction plate, and that a plurality of suction holes 944a are further formed along the circumferential direction of the edge suction plate 945 adjacent to the central suction plate 943 in order to more strongly suction the bottom edge of the bonding object 11. The other configurations and operational relationships are the same as those of the embodiment shown in Figure 26a, so detailed description will be omitted.

[0314] In addition, as shown in Figures 26a and 26b, by adjusting the vacuum suction force of the central suction plate 943 and border suction plates 944 and 945 of the vacuum chuck 940, it is possible to expect that the unique bends or wrinkles of the printed circuit board (PCB) of the bonding object 11, for example, a flexible circuit board (Flexible PCB), can be straightened to a certain extent. As a result, the vertical height of the electronic components placed on the board is improved to be positioned at approximately the same point, thereby achieving the effect of improving process defects caused by excessive pressure being applied to certain electronic components during laser reflow.

[0315]

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

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

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

[0319] Meanwhile, the first laser module 310 and the second laser module 320 are provided with beam profilers 318 and 328, respectively, which constantly monitor the laser beam output and intensity of the first and second laser modules 310 and 320. As an example, the beam profilers 318 and 328 are configured to be provided on the laser beam paths of the first and second laser modules 310 and 320, and can measure the laser beam output and intensity by irradiating or transmitting a portion of the output laser beam through the beam profiler.

[0320] According to an embodiment, the infrared temperature sensor 810 may be a single infrared temperature sensor 810, which measures the surface temperature of the area 12 where the laser beams from the first and second laser modules are overlappingly irradiated. At this time, the single infrared temperature sensor 810 measures the temperature of multiple points in the area where the laser beams are overlappingly irradiated, sequentially, to measure the overall temperature distribution of the area where the laser beams are overlappingly irradiated.

[0321] If such temperature distribution values are measured to be uneven, for example, at a point where the temperature value is measured to be higher than the solder melting temperature, an overflow bonding failure due to overheating of the solder may occur. Conversely, if the temperature value is measured to be lower than the solder melting temperature, the solder may not be sufficiently melted, resulting in a bonding failure where the connection cannot be made.

[0322] For this reason, in the present invention, the infrared temperature sensor 810 constantly measures the temperature of the overlapping irradiation area, and adjusts the output, intensity, beam shape, etc. of each laser beam output from the first or second laser module 310, 320 to compensate for the temperature distribution value in the overlapping irradiation area 12.

[0323] Meanwhile, in another embodiment of the present invention, multiple infrared temperature sensors 810 may be provided. Referring to FIG. 28, the multiple infrared temperature sensors of the present invention may be, for example, five temperature sensors 810#1, 810#2, 810#3, 810#4, and 810#5. The arrangement may include one temperature sensor 810#1, 810#2, 810#3, and 810#4 located at each edge, and one temperature sensor 810#5 located in the center. Therefore, the five infrared temperature sensors 810#1, 810#2, 810#3, 810#4, and 810#5 simultaneously irradiate infrared beams. In this case, the infrared beams are irradiated and temperatures are measured on electronic components 11b#1, 11b#3, 11b#7, and 11b#9 located at each edge of square region 12 and electronic component 11b#5 located in the center, as shown in FIG. 29.

[0324] In this case, the positions and number of electronic components 11b whose temperatures are measured are not specified as described above, and the temperature of the surface of the board on which no electronic components are located can also be measured. In order to obtain a more accurate temperature distribution value in the area where the laser beam is irradiated in an overlapping manner, this can be achieved by measuring the temperature values of as many electronic components and boards as possible.

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

[0326]

[0327] 30a to 30e are diagrams showing the operational relationships between the steps of the laser reflow method of the present invention, and the laser reflow method for each step will be described below according to one embodiment.

[0328] 30a is a diagram showing a state in which the light-transmitting pressing member 100 has moved above the center line Cn+1, and when the pressing surface 102 of the light-transmitting pressing member 100 is positioned 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 light-transmitting pressing member 100. At this time, the vision unit 934 determines whether the electronic component 11b is arranged symmetrically with respect to the center line Cn+1 of the pressing surface 102 of the light-transmitting pressing member 100 when viewed from the side as shown in FIG.

[0329] That is, assuming that the shape of the electronic components 11b located directly below the pressure surface 102 of the light-transmitting pressure member 100 is positioned to correspond to the area of the pressure surface 102, for example, as shown in Fig. 10a, where the electronic components 11b are arranged in three rows, it is determined whether the electronic components 11b are arranged symmetrically in 1.5 rows with respect to the center line Cn+1 of the pressure surface 102. This ensures that when the pressure surface 102 of the light-transmitting pressure member 100 presses and applies pressure to the area (area) where the electronic components 11b are arranged in three rows, the pressure is not biased to either side, and the pressure is applied in a balanced manner.

[0330] Referring to the drawing, electronic component 11b of bonding object 11 is positioned on the top surface of substrate 11a together with solder 11c for bonding, and is fixed by vacuum chucking to vacuum chuck 940 below substrate 11a. A heating block 942 is installed inside vacuum chuck 940, which continuously preheats substrate 11a, electronic component 11b, and solder 11c (bonding object 11) to a predetermined temperature. For example, the preheating temperature is preferably set below the melting point of the solder, and can be maintained below 200°C, a temperature range in which substrate 11a and electronic component 11b are not thermally damaged even if exposed for a certain period of time.

[0331] If the bonding object 11 is not preheated as described above, the bonding object 11 must be rapidly heated from room temperature to the melting temperature of the solder 11c using only the thermal energy of the laser beam during the laser reflow process, which is the main process. Rapid heating can lead to overflow of the solder 11c and other bonding defects. Therefore, gradually increasing the temperature from the preheating temperature to the melting temperature of the solder 11c ensures stable melting of the solder 11c, minimizing bonding defects. For example, the melting temperature of the solder 11c may vary depending on the solder material, but may be 200°C or higher, which is the melting temperature of a typical solder paste.

[0332]

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

[0334] At this time, the laser beam can be irradiated simultaneously or sequentially with the application of pressure to the light-transmitting pressure member 100. For example, at the same time that the light-transmitting pressure member 100 is being applied with pressure, the laser beams can be irradiated onto the electronic component 11b in a superimposed manner from the multi-laser module, the first laser module 310, and the second laser module 320 located above.

[0335] As a result, the bonding object 11 is heated in stages by the superimposed laser beams from the preheating temperature to the melting temperature of the solder 11c, and finally the solder 11c located below the electronic component 11b melts, completing the bonding of the electronic component 11b to the substrate 11a. (The height difference before and after bonding is represented as hc in Figure 30a.)

[0336]

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

[0338] 30c, after the previous laser reflow process is completed, the light-transmitting pressing member 100 horizontally transports the electronic components 11b to the next predetermined area, that is, the center line Cn+2 of the three rows of electronic components 11b, to apply pressure and laser reflow to the three rows of electronic components 11b. At this time, the vision unit 934 again captures an image of the layout of the electronic components 11b arranged below the pressing surface 102 of the light-transmitting pressing member 100.

[0339] However, if it is determined that electronic components 11b arranged below pressure surface 102 of light-transmitting pressure member 100 are not arranged symmetrically with respect to center line Cn+2, as shown in Figure 30c, pressure application and laser irradiation are not immediately carried out. The reason for this is that if pressure is applied to light-transmitting pressure member 100 in this state, the pressure applied to electronic components 11b will be biased toward one side because electronic components 11b are arranged asymmetrically with respect to center line Cn+2 of pressure surface 102 of light-transmitting pressure member 100, resulting in bonding defects.

[0340] To prevent this, in the present invention, a control unit (not shown) moves the horizontal position of the light-transmitting pressing member 100 to a new center line Cn+2' as shown in Figure 30d, and the horizontal position of the light-transmitting pressing member 100 is corrected accordingly at the corrected center line Cn+2'.As a result, the horizontal position of the electronic component 11b arranged below the light-transmitting pressing member 100 is corrected so that it is arranged symmetrically with respect to the corrected center line Cn+2'.In this state, the light-transmitting pressing member 100 moves downward as shown in Figure 30e, presses the electronic component 11b, and irradiates the laser beam onto it.

[0341]

[0342] Meanwhile, referring to FIG. 30e, the transparent pressure member 100 moves to the corrected center line Cn+2' to apply pressure, and at that time, the first and second laser modules 310 and 320 do not correct their horizontal positions on the corrected center line Cn+2', but irradiate laser beams based on the pre-correction center line Cn+2.

[0343] The reason why the laser modules 310, 320 do not correct the horizontal position along the transparent pressure member 100 as described above is that if the laser beam were irradiated based on the corrected center line Cn+2', the laser beam could be irradiated again on an electronic component that has already been bonded, and if the laser beam were to be irradiated again on the reflowed solder 11c, the solder 11c could be remelted, resulting in a bonding failure. Therefore, in the present invention, when applying pressure and applying laser to an asymmetrically arranged electronic component 11b, the first or second laser module 310, 320 is not corrected in position, but rather the transparent pressure member 100 is horizontally moved along the corrected center line Cn+2' to correct the position, and then pressure and laser irradiation are performed, thereby minimizing the occurrence of various bonding failure factors as described above.

[0344]

[0345] 1 is a state diagram showing the operational relationship of each process of a laser reflow method according to the present invention. Various bonding modes that can be combined with each process will be described below according to embodiments.

[0346] First, referring to FIG. 31a, the first bonding mode of the present invention is the most basic bonding mode, and can proceed to a step in which the pressure surface 102 of the transparent pressure member 100 moves downward to contact the bonding object 11 without applying pressure, a step in which a laser beam is irradiated onto the bonding object 11 through the transparent pressure member 100, and a step in which the irradiation of the laser beam is stopped and the transparent pressure member 100 is moved upward.

[0347] At this time, the step in which the transparent pressing member 100 comes into contact without applying pressure is as shown in Fig. 13, in which the motor 760 is driven and connected to the ball screw 750. The press bracket 720 moves downward, and since the holder unit 500 and the transparent pressing member 100 are attached to the press bracket 720, the transparent pressing member 100 is finally moved downward by the driving of the motor.

[0348] 31b, in the next step, when the transparent pressing member 100 is moved downward and contacts the electronic component 11b of the bonding target 11, a driving force is applied to move the transparent pressing member 100 downward. The driving of the motor 760 is stopped, and the transparent pressing member 100 contacts the upper surface of the electronic component 11b without applying any pressure. At this time, because the motor is locked, the height of the transparent pressing member 100 is fixed so that it does not move vertically.

[0349] Next, as shown in the next step in FIG. 31c, with the light-transmitting pressure member 100 in contact with the upper surface of the electronic component 11b, the multi-laser modules, i.e., the first laser module 310 and the second laser module 320, provided above the light-transmitting pressure member 100 irradiate a laser beam onto the bonding object 11 through the light-transmitting pressure member 100.

[0350] At this time, the laser beam is superimposed and irradiated, thereby transmitting a homogenized laser beam to the plurality of electronic components 11b and solder 11c, and since the bonding object 11 has already been preheated to a certain preheat temperature, for example, less than 200°C, as described above, the laser beam can stably heat the bonding object 11 from the preheat temperature to the melting temperature of the solder 11c, for example, 250°C, without suddenly heating the bonding object 11 to the melting temperature of the solder 11c. As a result, when laser reflow is started, the pressure surface 102 of the transparent pressure member 100 is in contact with the upper surface of the solder 11c, so that the electronic components 11b located above the solder 11c are confined so as not to bend or stretch upward when the solder 11c melts.

[0351] Thereafter, when soldering is completed, the irradiation of the laser beam is stopped and the light-transmitting pressure member 100 is moved upward, thereby completing the first bonding mode.

[0352]

[0353] Meanwhile, let us look at an embodiment of another bonding mode in which some steps are added to the first bonding mode.

[0354] In the second bonding mode, similarly to the first bonding mode described above, after the light-transmitting pressure member 100 comes into contact with the electronic component 11b of the bonding target 11, the pressure cylinder 730 provided above the light-transmitting pressure member 100 presses the light-transmitting pressure member 100 at a constant pressure.

[0355] Thereafter, when a laser beam is irradiated while the transparent pressing member 100 is pressing the bonding object 11 as described above, the pressing force is released as the solder 11c of the bonding object 11 melts, and it is expected that the height of the electronic component 11b will then decrease by a certain height (hc, see FIG. 31a) due to the compression of the solder 11c. If the motor 760 is unlocked in this state, the transparent pressing member 100 will gradually move downward due to its own weight, and ultimately will move downward by the amount of the pressing force applied by the pressure cylinder 730, thereby maintaining the pressing force.

[0356] Therefore, the second bonding mode differs from the initial bonding mode in that pressure is applied before the laser beam is irradiated, and when the solder 11c melts after the laser beam is applied, the transparent pressing member 100 also moves downward to maintain the pressure. As a result, the pressure applied to the solder 11c when it melts is kept constant, which is expected to reduce lifting of the electronic component 11b and poor connection of the solder 11c, resulting in high-density soldering.

[0357]

[0358] Furthermore, the third bonding mode is similar to the first bonding mode described above in that after the translucent pressure member 100 comes into contact with the electronic component 11b of the bonding target 11, a laser beam is irradiated without applying pressure.

[0359] After the laser beam is irradiated, the pressure cylinder 730 is driven to apply a constant pressure to the light-transmitting pressure member 100 and the bonding object 11. At this time, the motor 760 is locked and fixed to prevent the light-transmitting pressure member 100 from moving vertically, and only the pressure cylinder 730 applies pressure. The third bonding mode differs from the first bonding mode in that pressure 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 differs in that the height of the light-transmitting pressure member 100 is changed instead of applying pressure after irradiating the laser beam.

[0362] Therefore, when irradiation of the laser beam begins, the motor is unlocked and the translucent pressure member 100 gradually moves downward, ultimately gradually pressing the electronic component 11b and the melting solder 11c, thereby preventing bonding failures caused by a sudden pressure being applied to the melting solder 11c by the laser beam.

[0363]

[0364] As described above, the bonding mode can be embodied in various ways in terms of adjusting pressure changes caused by melting of solder to prevent bonding failure.

[0365] Therefore, the present invention is not limited to the embodiments described above, and similar effects can be achieved by changing the detailed configuration, number, and layout structure of the device, or by changing and adding detailed steps. Therefore, it is clearly stated that a person with ordinary knowledge in the relevant technical field can add, delete, and modify various configurations within the scope of the technical concept of the present invention.

[0366]

[0367] Explanation of symbols

[0368] 11: Bonding object 11a: Substrate

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

[0370] 100: Permeable pressure member 101: Base material

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

[0372] 102a: grating groove 103: laser light blocking layer

[0373] 104: Silicone damper layer 200: Protective film

[0374] 210: Protective film conveying section 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 transport unit

[0379] 630: Probe bracket 700: Press unit

[0380] 710: Pressure balancer 720: Press bracket

[0381] 730: Pressure cylinder 740: Pressure sensor

[0382] 750: Ball screw 760: Motor

[0383] 770: Guide member 780: Bearing joint

[0384] 790: Stopper 800: Ionizer

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

[0386] 910: Input conveyor 920, 960: Horizontal transport 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 that bonds electronic components to a substrate by pressing a bonding target, which is a rectangular substrate on which a plurality of electronic components are arranged, with a light-transmitting pressure member and applying pressure while irradiating a laser beam through the light-transmitting pressure member, comprising: a) moving a pressure surface of the transparent pressure member downward to contact the bonding object without applying pressure; b) irradiating a laser beam onto the bonding object through the light-transmitting pressure member; and c) a step of ceasing the irradiation of the laser beam and moving the light-transmitting pressure member upward; and

2. 2. The laser reflow method according to claim 1, further comprising the step of fixing the vertical movement of the light-transmitting pressure member after the step a).

3. 2. The laser reflow method according to claim 1, further comprising the steps of: applying a predetermined constant pressure to the light-transmitting pressure member after the step a); and not fixing the vertical movement of the light-transmitting pressure member after the step b).

4. 2. The laser reflow method according to claim 1, further comprising the steps of: fixing the vertical movement of the light-transmitting pressure member after the step a); and applying a predetermined constant pressure to the light-transmitting pressure member after the step b).

5. 2. The laser reflow method according to claim 1, further comprising the steps of: fixing the vertical movement of the light-transmitting pressure member after the step a); and not fixing the vertical movement of the light-transmitting pressure member after the step b).

6. 2. The laser reflow method according to claim 1, wherein in step b), laser beams emitted from two or more laser modules are superimposed and irradiated.

7. 7. A laser reflow method for a laser reflow apparatus according to claim 6, wherein the laser beams are emitted simultaneously from the laser modules.

8. 7. A laser reflow method for a laser reflow apparatus according to claim 6, wherein the laser beams are emitted sequentially from the laser modules.

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

10. 10. The laser reflow method for a laser reflow apparatus according to claim 9, wherein the step of preheating the bonding object at the lower portion maintains the surface temperature of the bonding object at less than 200°C.

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