Laser reflow soldering device and laser reflow soldering method

Abstract

The laser reflow soldering device of the present invention includes: a laser pressurizing head module that pressurizes a soldering object through a light-transmissive pressurizing member and irradiates a laser beam through the pressurizing member to solder an electronic component to a substrate, where the soldering object is composed of a plurality of electronic components arranged on the substrate; and a soldering object transfer module for transferring the soldering object so that the soldering object carried in from one side of the laser pressurizing head module undergoes reflow soldering treatment by the laser pressurizing head module and is carried out toward the other side.

Description

Technical Field

[0001] The present invention relates to a laser reflow soldering apparatus and a laser reflow soldering method. More specifically, the present invention relates to a laser reflow soldering apparatus having a pressurizing method and a laser reflow soldering method using the apparatus, in which a plurality of electronic components arranged on a substrate are pressed by a light-transmitting pressurizing member and then irradiated with laser to simultaneously solder the electronic components. Background Art

[0002] In industrial laser processing, the application field with micron (μm) level precision is micro laser processing, which is widely used in the semiconductor industry, display industry, printed circuit board (PCB) industry, smartphone industry, etc. In the memory chips used in all electronic devices, in the past, integration, performance, and ultra-high-speed communication speed were achieved by maximizing the reduction of circuit pitch. However, since it is difficult to achieve the required technical level only by reducing the circuit line width and line width interval, multiple memory chips are stacked vertically. TSMC has developed a 128-layer stacking technology, and Samsung Electronics, SK Hynix, etc. have applied a 72-layer stacking technology to mass production.

[0003] In addition, active research and development are being carried out on a technology of loading memory chips, microprocessor chips, graphics processor chips, wireless processor chips, sensor processor chips, etc. into one package, and a considerable level of technology has been applied in practice.

[0004] However, in the development process of the above technologies, as more and more electronic components interfere with the signal processing process inside the ultra-high-speed / large-capacity semiconductor chips, there are problems of heat dissipation due to increased power consumption. In addition, in order to meet the requirements of ultra-high-speed signal processing and ultra-high-frequency signal processing for more signals, there are technical problems of high-speed transmission of a large number of electrical signals. Moreover, as the number of signal lines increases, since the signal interface lines facing the outside of the semiconductor chip cannot be further processed by the one-dimensional lead method, the ball grid array (BGA) method of two-dimensional processing under the semiconductor chip (fan-in ball grid array package (Fan-In BGA) or fan-in wafer-level package (FIWLP, Fan-in Wafer-Level-Package)) and a method of forming a signal layout redistribution layer under the ultra-fine BGA layer under the chip and forming a second fine BGA layer under it (fan-out ball grid array package (Fan-Out BGA) or fan-out wafer-level package (FOWLP, Fan-Out Wafer-Level-Package) or fan-out panel-level package (Fan-Out Panel-Level-Package)) are adopted.

[0005] Recently, as a semiconductor chip, a product with a thickness of less than 200 μm including an epoxy-mold compound (EMC) layer has been developed. In order to attach such a micro-thin semiconductor chip with a thickness of only a few hundred micrometers to an ultra-thin printed circuit board, if the mass reflow (MR) process, which is the standard process of the existing surface mount technology (SMT), is applied, for example, the thermal reflow oven technology, then, as the semiconductor chip is exposed to the air temperature environment of 100°C to 300°C for several hundred seconds, various types of soldering bond failures may occur due to the difference in the coefficient of thermal expansion (CTE), such as chip-boundary warpage, PCB-boundary warpage, random-bonding failure by thermal shock, etc.

[0006] Therefore, in the recently spotlighted laser reflow soldering device, its structure is a method of performing soldering by pressing the soldering object (semiconductor chip or integrated circuit IC) for several seconds with a laser head module and irradiating laser. Therefore, soldering is performed by irradiating laser in the form of a surface light source corresponding to the size of the semiconductor chip or integrated circuit.

[0007] As a reference related to such a pressurized laser reflow soldering device, there is Korean Patent No. 0662820 (hereinafter, referred to as "Prior Art 1"), the structure of which heats the flip chip by irradiating laser on the back of the flip chip, and on the other hand, discloses a flip chip heating and pressing module for pressing the flip chip onto the carrier substrate.

[0008] However, in the existing pressurized laser reflow soldering device disclosed in the above Prior Art 1, since the unit for adsorbing the chip and moving it to the soldering position is separated from the unit for heating the back of the chip with laser and pressing the chip onto the carrier substrate, in the case of soldering multiple semiconductor chips such as semiconductor strips, there is a problem of increased working time because the operation of pressing one semiconductor chip while irradiating laser needs to be repeatedly performed according to the number of semiconductor chips.

[0009] On the other hand, referring to Korean Patent Publication No. 2017-0077721 (hereinafter referred to as "Prior Art Document 2"), the structure of the disclosed laser reflow soldering apparatus performs soldering processing by moving a laser head horizontally along while simultaneously pressing a plurality of flip chips with a pressing head and irradiating a single laser to each flip chip in sequence or irradiating a plurality of flip chips with a single laser head simultaneously.

[0010] However, since the prior laser reflow soldering apparatus structure of the above Prior Art Document 2 uses a single laser source, in the process of irradiating laser beams to a plurality of flip chips arranged on a substrate at various angles, it is difficult to irradiate a homogenized laser beam, and technically, there is a problem that it is impossible to uniformly perform reflow soldering processing on a plurality of flip chips without defects.

[0011] Therefore, the prior laser reflow soldering apparatuses disclosed in the above Prior Art Document 1 and the above Prior Art Document 2 press and irradiate a single flip chip one by one in sequence, so the overall working time will inevitably increase. Even if a single laser beam is irradiated to a plurality of flip chips horizontally arranged on various substrate sizes in order to achieve multi-processing, it is actually difficult to transfer uniform thermal energy to each flip chip. Therefore, in order to improve the soldering defect rate, a large amount of research and development is currently required. Summary of the Invention

[0012] Technical Problem

[0013] In view of this, in order to solve the above problems, an object of the present invention is to provide a laser pressing head module of a laser reflow soldering apparatus as follows, that is, by replacing a light-transmissive pressing member, the size of the pressing and laser light-transmissive area after a single processing can be easily adjusted to correspond to the sizes of various substrates. Thus, a plurality of electronic components can be batch-processed simultaneously by pressing and laser reflow soldering, and the defect rate can be significantly improved.

[0014] Moreover, another object of the present invention is to provide a laser pressing head module of a laser reflow soldering apparatus as follows, that is, by simultaneously pressing a plurality of electronic components and irradiating a homogenized laser beam, the defect rate can be significantly improved while achieving batch processing.

[0015] Furthermore, still another object of the present invention is to provide a laser pressing head module of a laser reflow soldering apparatus as follows, that is, the pressure of each corner part of a plate-shaped bracket unit on which a light-transmissive pressing member is installed can be independently set and adjusted. Thus, a plurality of electronic components can be simultaneously pressed and irradiated with laser beams for a single reflow soldering process, and the defect rate can be significantly improved while achieving batch processing.

[0016] Moreover, another object of the present invention is to provide a laser pressurizing head module of a laser reflow soldering device as follows, that is, by means of a conveyor system, the loading and unloading of a soldering object with a plurality of electronic components placed on a substrate into and out of a reflow soldering processing area can be made simple without considering the size. During the loading transfer process, the soldering object can be continuously preheated to a specified temperature so that the temperature during laser reflow soldering processing can stably rise to the solder melting temperature without any defects. Thus, by simultaneously pressurizing a plurality of electronic components and irradiating a laser beam for one-time reflow soldering processing, batch processing can be achieved while significantly improving the defect rate.

[0017] Furthermore, another object of the present invention is to provide a multi-laser module of a laser reflow soldering device as follows, that is, by precisely detecting the area where multiple laser beams overlap and irradiate through a plurality of temperature sensors, the temperature non-uniformity of the substrate and electronic components constituting the soldering object can be immediately detected and compensated, thereby preventing soldering defects of specific electronic components. Thus, by simultaneously pressurizing a plurality of electronic components and irradiating a laser beam for one-time reflow soldering processing, batch processing can be achieved while significantly improving the soldering defective products caused by temperature non-uniformity.

[0018] Moreover, another object of the present invention is to provide a laser reflow soldering method of a laser reflow soldering device as follows, that is, before the light-transmissive pressurizing member is pressurized, by adjusting the configuration shape of the electronic component located below so that it is at the exact center of the pressurizing surface of the light-transmissive pressurizing member, the pressure transmitted to the electronic component can be evenly pressurized without being biased to one side during the pressurizing process of the above light-transmissive pressurizing member. Thus, by simultaneously pressurizing a plurality of electronic components and irradiating a laser beam for one-time reflow soldering processing, batch processing can be achieved while significantly improving the defect rate.

[0019] Moreover, another object of the present invention is to provide a laser reflow soldering method of a laser reflow soldering device as follows, that is, pressurize a plurality of electronic components under preset conditions and sequentially control the irradiation process of the laser beam. Thus, a one-time batch reflow soldering process can be carried out on a plurality of power fittings without any soldering defects, and the defect rate can be significantly improved.

[0020] Solution to the problem

[0021] To achieve the above object, the present invention includes: a laser pressurizing head module that pressurizes a soldering object through a light-transmissive pressurizing member and irradiates a laser beam through the above pressurizing member to solder an electronic component to a substrate, where the soldering object is composed of a plurality of electronic components arranged on the substrate; and a soldering object transfer module for transferring the above soldering object so that the soldering object loaded from one side of the above laser pressurizing head module undergoes reflow soldering processing by the laser pressurizing head module and is transported out towards the other side.

[0022] Moreover, the above-mentioned laser pressurization head module includes: a bracket unit for detachably mounting the above-mentioned light-transmissive pressurizing member; and a probe unit disposed above the bracket unit for detecting the flatness of the pressurizing member mounted on the bracket unit.

[0023] Moreover, the above-mentioned laser beam is a square laser beam homogenized by a beam shaper.

[0024] Moreover, the above-mentioned laser beam is a laser beam formed by overlapping two or more laser modules.

[0025] Moreover, the above-mentioned bracket unit includes a lower plate having a through hole formed in a central portion for inserting, locking, and placing the light-transmissive pressurizing member.

[0026] The above-mentioned light-transmissive pressurizing member is made of one of quartz, sapphire, fused silica glass, or diamond.

[0027] Moreover, the above-mentioned bracket unit further includes a mask plate having a through hole formed in a central portion through which the laser beam can pass, such that the above-mentioned light-transmissive pressurizing member is combined with the upper portion of the lower plate in a state of being placed on the lower plate.

[0028] Moreover, the through hole of the above-mentioned mask plate is a square having an area larger than or the same as the pressurizing surface of the light-transmissive pressurizing member.

[0029] Moreover, the bottom surface of the above-mentioned lower plate has a circular arc shape at both left and right corner portions.

[0030] Moreover, at each corner portion of the above-mentioned lower plate, a flatness adjustment unit is further provided for adjusting the flatness of the light-transmissive pressurizing member by finely moving the corner of the lower plate in the vertical direction.

[0031] Moreover, the above-mentioned flatness adjustment unit includes: a stamping bracket disposed at each corner portion of the light-transmissive pressurizing member and the bracket unit; and a vertical driving unit disposed on one side of the stamping bracket for moving the stamping bracket in the vertical direction by driving a motor.

[0032] Moreover, the above-mentioned vertical driving unit includes: a ball screw and a motor for vertically moving the stamping bracket; and a guiding member for guiding the linear motion of the stamping bracket.

[0033] Moreover, the above-mentioned probe unit includes: a probe for measuring flatness by piercing one or more positions on the upper surface of the light-transmissive pressurizing member; a moving unit for horizontally or vertically moving the above-mentioned probe; and a probe bracket for fixing the above-mentioned probe and the moving unit.

[0034] Moreover, the above-mentioned probe punctures four or more positions including the respective corner positions of the square on the upper surface of the light-transmissive pressing member.

[0035] Furthermore, the present invention further includes a protective film formed on the lower part of the above-mentioned light-transmissive pressing member to prevent the gas (fumes) generated during laser welding from adhering to the bottom surface of the light-transmissive pressing member.

[0036] Moreover, the above-mentioned protective film is made of polytetrafluoroethylene resin (PTFE) or soluble polytetrafluoroethylene resin (PFA).

[0037] Moreover, the above-mentioned protective film is supplied by a protective film transfer unit, and the protective film transfer unit unfolds the protective film wound in a roll shape by a reel-to-reel method and transfers it to one side.

[0038] Moreover, the above-mentioned light-transmissive pressing member includes: a substrate, which is integrally in the shape of a square plate; and a pressing surface, which protrudes from the bottom surface of the substrate and forms a planar shape corresponding to a plurality of electronic components on the bottom surface.

[0039] Moreover, between the above-mentioned substrate and the pressing surface, there is also included one or more stepped portions that are recessed inward so that the area of the pressing surface is smaller than the area of the substrate.

[0040] Moreover, a laser barrier layer is formed on the side surface of the above-mentioned substrate, the bottom surface, and the side surface of the stepped portion.

[0041] Moreover, the above-mentioned pressing surface is divided into two or more by grid grooves having a specified depth.

[0042] Moreover, a laser barrier layer is also formed on the inner side surface and the bottom surface of the above-mentioned grid grooves.

[0043] Moreover, the above-mentioned laser barrier layer is a composite layer composed of one or two or more of an Inconel coating, a scattering treatment layer, or a high reflection (HR) coating.

[0044] Moreover, the above-mentioned pressing surface is square.

[0045] Moreover, the two side corners of the above-mentioned pressing surface are chamfered or rounded.

[0046] Moreover, an elastic damping layer is also provided on the above-mentioned pressing surface.

[0047] Moreover, the above-mentioned elastic damping layer is made of silicon material.

[0048] Moreover, the above-mentioned laser pressing head module further includes: a bracket unit, which is rectangular and is used to install the above-mentioned light-transmitting pressing component in a replaceable manner; a pressure balancer, which supports the lower ends of the respective corners of the above-mentioned bracket unit and applies pressures in opposite directions equivalent to the weight of the bracket unit and the weight of the light-transmitting pressing component, so that the weights of the bracket unit and the light-transmitting pressing component are initialized to zero; and a stamping unit, which is arranged above the respective corners of the above-mentioned bracket unit in a non-contact state and independently presses the respective corners of the bracket unit with a preset pressure.

[0049] Moreover, the above-mentioned pressure balancer is an air cylinder.

[0050] Moreover, the above-mentioned pressure balancer is a spring.

[0051] Moreover, one of the above-mentioned stamping units is separately arranged at each corner, so that the stamping units independently press the respective corners of the bracket unit with a preset pressure.

[0052] Moreover, the above-mentioned stamping unit includes: a stamping bracket, which fixes the respective corner portions of the bracket unit in a non-contact manner; and a pressing cylinder, which is installed at the upper end of the above-mentioned stamping bracket and presses the above-mentioned bracket unit downward with a preset pressure respectively.

[0053] Moreover, the above-mentioned pressing cylinder is a precision pneumatic cylinder, which can achieve fine setting and adjustment of pressure in units of kgf.

[0054] Moreover, a pressure sensor for measuring the pressure during pressing and continuously performing feedback is further provided on the above-mentioned pressing cylinder.

[0055] Moreover, an ionizer unit for keeping the upper surface of the light-transmitting pressing component clean from the influence of dust adsorption caused by static electricity is further provided above the above-mentioned bracket unit.

[0056] Moreover, the above-mentioned welding object transfer module includes: an input conveyor for transporting welding objects, which are composed of a plurality of electronic components arranged on a substrate; a vacuum chuck unit for fixing the welding objects transferred from the above-mentioned input conveyor by vacuum adsorption; and an output conveyor for transporting the welding objects that have completed the laser reflow soldering process.

[0057] Moreover, the above-mentioned input conveyor and the above-mentioned output conveyor include: a conveyor frame; a pair of linear guide units arranged on both upper sides of the above-mentioned conveyor frame; and a horizontal transfer unit arranged on one side of the above-mentioned conveyor frame for linearly moving the conveyor frame in the horizontal direction.

[0058] In addition, a width adjustment unit is provided on one side of the conveyor frames of the above-mentioned input conveyor and the above-mentioned output conveyor to accommodate welding objects of different sizes by expanding or reducing the width of the conveyor frames.

[0059] In addition, a preheating table is provided on the conveyor frame of the above-mentioned input conveyor for preheating the welding object to a specified temperature.

[0060] In addition, a vision unit is provided on one side of the above-mentioned vacuum chuck unit for monitoring whether the welding object is loaded normally.

[0061] In addition, a pick-up unit for transferring the welding object is provided between the above-mentioned input conveyor and the vacuum chuck unit and between the above-mentioned output conveyor and the vacuum chuck unit respectively.

[0062] In addition, the above-mentioned pick-up unit includes: a vacuum adsorption pad, which is in a flat plate shape; and a vertical driving part for moving the above-mentioned vacuum adsorption pad along the vertical direction.

[0063] In addition, the above-mentioned vacuum chuck unit includes: a porous adsorption plate for adsorbing and fixing the welding object; and a horizontal moving unit for reciprocally moving the above-mentioned porous adsorption plate and the heating block in the area from the input area of the welding object through the laser reflow soldering processing area to the output area.

[0064] In addition, the above-mentioned porous adsorption plate is composed of a central adsorption plate and an edge adsorption plate. The central adsorption plate is rectangular and is used for adsorbing the center part of the bottom surface of the welding object. The edge adsorption plate surrounds the periphery of the central adsorption plate and is used for adsorbing the edge part of the bottom surface of the welding object.

[0065] In addition, adsorption holes for adsorbing the edge part of the bottom surface of the welding object are formed in the above-mentioned edge adsorption plate.

[0066] In addition, the above-mentioned edge adsorption plate is made of aluminum material.

[0067] In addition, a heating block is provided below the above-mentioned porous adsorption plate.

[0068] In addition, the above-mentioned laser pressure head module includes: a multi-laser module for overlapping and irradiating a plurality of laser beams on the above-mentioned welding object in a state of being arranged at intervals; and a temperature sensor provided in the area between the above-mentioned multi-laser modules for detecting the temperatures of a plurality of positions of the welding object by irradiating light beams through a light-transmissive pressure member.

[0069] In addition, the above-mentioned multi-laser module is a pair of multi-laser modules facing each other.

[0070] In addition, the above-mentioned temperature sensor is a single infrared temperature sensor, and the single infrared temperature sensor sequentially irradiates infrared rays on a plurality of positions of the welding object.

[0071] Further, the single infrared temperature sensor irradiates infrared rays to a plurality of positions in the peripheral part and the central part within the area where a plurality of laser beams are overlappedly irradiated in sequence.

[0072] Further, the temperature sensors are a plurality of infrared temperature sensors, and the plurality of infrared temperature sensors irradiate infrared rays to a plurality of positions of the object to be welded simultaneously.

[0073] Further, the plurality of infrared temperature sensors irradiate infrared rays to a plurality of positions in the peripheral part and the central part within the area where a plurality of laser beams are overlappedly irradiated simultaneously.

[0074] Further, a beam analyzer is also provided in the multi-laser module for measuring the power and intensity of each laser beam.

[0075] Further, the laser reflow soldering method of the laser reflow soldering apparatus of the present invention presses a welding object on which a plurality of electronic components are arranged on a rectangular substrate through a light-transmissive pressing member and irradiates a laser beam through the pressing member to solder the electronic components to the substrate, including: step a), before the light-transmissive pressing member presses the welding object, photographing the arrangement shapes of a plurality of electronic components within a specified range directly below the pressing surface of the light-transmissive pressing member through a vision unit; step b), determining whether the photographed arrangement shapes of the plurality of electronic components within the specified range correspond to the pressing surface; step c), when it is determined that the plurality of electronic components correspond to the pressing surface, the light-transmissive pressing member moves downward and presses the welding object, and irradiates the laser beam to the welding object through the light-transmissive pressing member; step d), stopping the irradiation of the laser beam and moving the light-transmissive pressing member upward to release the pressing state; and step e), horizontally moving the plurality of electronic components within the specified range to be subjected to reflow soldering treatment by the light-transmissive pressing member upward.

[0076] Further, the above step b) includes: step b1), determining whether the plurality of electronic components are symmetric about the center line of the pressing surface of the light-transmissive pressing member when observing the arrangement shapes of the plurality of electronic components within the specified range photographed from the side; and step b2), when the photographed arrangement shapes of the plurality of electronic components are symmetric about the center line of the pressing surface of the light-transmissive pressing member, determining that they correspond to the pressing surface, and when they do not correspond to the pressing surface, adjusting the horizontal position of the light-transmissive pressing member so that the arrangement shapes of the plurality of electronic components are symmetric about the center line of the pressing surface of the light-transmissive pressing member.

[0077] Further, the laser beam is a laser beam overlappedly irradiated by two or more laser modules.

[0078] Moreover, the above laser modules are symmetrically arranged with respect to each other, and the above laser beams each have the same beam irradiation angle.

[0079] Moreover, the above laser modules irradiate laser beams simultaneously.

[0080] Moreover, the above laser modules irradiate laser beams in sequence.

[0081] Moreover, before performing the above step c), the present invention further includes a step of preheating the welding object from below.

[0082] Moreover, in the step of preheating the above welding object from below, the surface temperature of the welding object is maintained at less than 200°C.

[0083] Moreover, in the above step c), a laser beam is irradiated onto the welding object through a light-transmissive pressing member to heat the surface temperature of the welding object to 200°C or more.

[0084] Moreover, the laser reflow soldering method of the laser reflow soldering device of the present invention presses a welding object on which a plurality of electronic components are arranged on a rectangular substrate through a light-transmissive pressing member and irradiates a laser beam through the above pressing member to solder the electronic components to the substrate, including: step a) moving the pressing surface of the above light-transmissive pressing member downward to contact the welding object in a state where no pressure is applied; step b) irradiating a laser beam onto the welding object through the above light-transmissive pressing member; and step c) canceling the irradiation of the above laser beam and moving the light-transmissive pressing member upward.

[0085] Moreover, after performing the above step a), the present invention further includes a step of fixing the vertical movement of the above light-transmissive pressing member.

[0086] Moreover, the present invention further includes the following steps: after performing the above step a), applying a preset specified pressure to the above light-transmissive pressing member, and after performing step b), not fixing the vertical movement of the above light-transmissive pressing member.

[0087] Moreover, the present invention further includes the following steps: after performing the above step a), fixing the vertical movement of the above light-transmissive pressing member, and after performing the above step b), applying a preset specified pressure to the above light-transmissive pressing member.

[0088] Moreover, the present invention further includes the following steps: after performing the above step a), fixing the vertical movement of the above light-transmissive pressing member, and after performing step b), not fixing the vertical movement of the above light-transmissive pressing member.

[0089] Moreover, in the above step b), the above laser beam is a laser beam overlapped and irradiated by two or more laser modules.

[0090] Moreover, each of the above laser modules irradiates a laser beam simultaneously.

[0091] Moreover, each of the above laser modules irradiates a laser beam in sequence.

[0092] Moreover, before performing the above step b), the present invention further includes a step of preheating the welding object from below.

[0093] Moreover, in the step of preheating the welding object from below, the surface temperature of the welding object is maintained at less than 200°C.

[0094] Effects of the Invention

[0095] The present invention as described above has the following effects. That is, since uniform thermal energy is transferred to the above-mentioned plurality of electronic components by simultaneously pressing the plurality of electronic components and irradiating a homogenized laser beam, the productivity can be greatly improved by batch laser reflow soldering processing.

[0096] Moreover, the mask plate and the light-transmissive pressing member can be replaced to correspond to the substrate size or the configuration shape of the electronic components. Therefore, uniform reflow soldering processing can be achieved for various substrates, and the defect rate can be greatly reduced.

[0097] Moreover, the degradation acceleration of the substrate and components caused by thermal damage to the peripheral part of the substrate of the electronic component due to the laser beam leaking from the edge part of the quartz that constitutes the pressing member can be prevented, thereby greatly reducing the defect rate.

[0098] Moreover, since the pressure of each corner part of the bracket unit on which the light-transmissive pressing member is mounted can be independently set and adjusted respectively, defective products caused by insufficient or excessive pressure acting on the plurality of electronic components arranged on the substrate can be prevented.

[0099] Moreover, the loading and unloading of the welding object with a plurality of electronic components placed thereon in a specified area on the substrate into and out of the reflow soldering processing area can be made simple and stable.

[0100] Moreover, the soldering defect rate can be greatly improved by detecting temperature non-uniformity in the multi-laser beam overlapping irradiation area and immediately detecting and compensating.

[0101] Moreover, the pressure of the light-transmissive pressing member is evenly dispersed and the electronic component is prevented from being inclined and pressed to one side. Thus, the defect rate caused by the pressure acting on the plurality of electronic components arranged on the substrate being biased to one side can be greatly improved by adjusting the position of the light-transmissive pressing member.

[0102] Moreover, based on a preset reference value, the pressing of the light-transmitting pressing member and the irradiation of the laser beam of the laser module can be precisely controlled in sequence to significantly improve various soldering defect problems that may occur due to insufficient or excessive pressure acting on multiple electronic components arranged on the substrate, such as poor contact or overflow of solder, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0103] Figure 1 FIG. is an exemplary diagram showing the overall structure of the laser reflow soldering apparatus of the present invention.

[0104] Figure 2 For Figure 1 the structural block diagram.

[0105] Figure 3 FIG. is a conceptual diagram of a single laser beam module of the laser reflow soldering apparatus according to an embodiment of the present invention.

[0106] Figure 4 FIG. is a conceptual diagram of a dual laser beam module of the laser reflow soldering apparatus according to another embodiment of the present invention.

[0107] Figure 5 FIG. is a structural diagram of a dual laser beam module of the laser reflow soldering apparatus according to another embodiment of the present invention.

[0108] Figures 6 to 9 FIG. is a structural diagram of a laser optical system applicable to a dual laser beam module of the laser reflow soldering apparatus according to another embodiment of the present invention.

[0109] Figure 10 FIG. is a main part perspective view briefly showing the bracket unit structure of the laser pressing head module of the present invention.

[0110] Figure 11 FIG. is a main part cross-sectional view briefly showing the bracket unit structure and working state of the laser pressing head module of the present invention.

[0111] Figure 12 FIG. is a main part perspective view briefly showing the probe unit structure and working state of the laser pressing head module of the present invention.

[0112] Figure 13 FIG. is a side view briefly showing the vertical transfer part structure and working state of the laser pressing head module according to an embodiment of the present invention.

[0113] Figure 14 FIG. is a main part perspective view briefly showing the vertical transfer part structure and working state of the laser pressing head module according to another embodiment of the present invention.

[0114] Figure 15 For Figure 14 the main part side cross-sectional view.

[0115] Figure 16a The top view of the main part of the bracket unit of the laser pressurizing head module according to an embodiment of the present invention is formed as an octagon.

[0116] Figure 16b The top view of the main part of the bracket unit of the laser pressurizing head module according to another embodiment of the present invention is formed as a circle.

[0117] Figure 17a And Figure 17b The perspective view of the main part showing the light-transmitting pressurizing member of the laser pressurizing head module of the present invention, Figure 17a The shape example diagram of the light-transmitting pressurizing member having a single pressurizing surface according to an embodiment of the present invention, Figure 17b The shape example diagram of the light-transmitting pressurizing member having a pressurizing surface divided corresponding to each electronic component according to another embodiment of the present invention.

[0118] Figure 18 The working state diagram showing the state where the light-transmitting pressurizing member of the present invention is installed on the pressurizing head.

[0119] [[ID=2 Is ​ The enlarged view of the main part.

[0120] ​ The schematic diagram showing various embodiments of the light-transmitting pressurizing member of the present invention, ​ Showing the case where the corners of the untreated pressurizing surface are not processed, ​ Showing the case where the corners of the pressurizing surface are chamfered, ​ Showing the case where the corners of the pressurizing surface are rounded.

[0121] ​ Briefly showing ​ The side cross-sectional view of the main part of the overall device structure of the laser pressurizing head module according to an embodiment.

[0122] ​ Is ​ The top view of the main part.

[0123] ​ Enlargedly showing ​ The perspective view of the main part of the stamping unit of the laser pressurizing head module according to an embodiment.

[0124] ​ The perspective view showing the input area structure and working relationship of the welding object transfer module according to an embodiment of the present invention.

[0125] ​ The perspective view showing the output area structure and working relationship of the welding object transfer module according to an embodiment of the present invention.

[0126] ​ and ​ FIG. is an exemplary diagram showing the structure and working relationship of the vacuum chuck unit of the welding object transfer module of the present invention, ​ showing the structure of a porous adsorption plate according to an embodiment, ​ showing the structure of a porous adsorption plate according to another embodiment.

[0127] ​ is a side view briefly showing the structure and working relationship of the multi-laser module according to another embodiment of the present invention.

[0128] ​ For magnifying and showing ​ a perspective view of the main part of the temperature sensor structure.

[0129] ​ For magnifying and showing ​ a top view of the main part of the welding object structure.

[0130] ​ is a state diagram showing the working relationship shown according to the process of the laser reflow soldering method of the present invention, ​ showing the state where the light-transmissive pressing member moves above the center line Cn+1, ​ showing the state where the light-transmissive pressing member presses and irradiates a laser at the center line Cn+1, ​ showing the state where the light-transmissive pressing member moves above the center line Cn+2, ​ showing the state where the position of the light-transmissive pressing member is calibrated based on the center line Cn+2', ​ showing the state where the light-transmissive pressing member presses and irradiates a laser at the center line Cn+2'.

[0131] ​ is a state diagram showing the working relationship shown according to the process of the laser reflow soldering method of the present invention, ​ showing the step of moving the light-transmissive pressing member above the welding object to be subjected to the next reflow soldering process after the previous reflow soldering process is completed, ​ showing the step of moving the pressing surface of the light-transmissive pressing member downward to contact the welding object in a non-pressurized state, ​ showing the step of irradiating a laser beam on the welding object through the light-transmissive pressing member, ​ showing the step of canceling the irradiation of the laser beam and moving the light-transmissive pressing member upward. Detailed Description of the Invention

[0132] The terms used in this specification are only for describing specific embodiments and do not limit the present invention. Unless clearly indicated otherwise in the context, singular expressions include plural expressions. It should be understood that terms such as "include", "have", and "be provided with" in this specification are only used to specify the existence of the features, numbers, steps, operations, structural elements, components, or combinations thereof described in this specification, and do not preclude the existence or additional possibility of one or more other features, numbers, steps, operations, structural elements, components, or combinations thereof in advance.

[0133] In this specification, unless otherwise defined, the meanings of all terms used herein, including technical terms or scientific terms, are the same as those commonly understood by those of ordinary skill in the technical field to which the present invention pertains.

[0134] Terms defined in commonly used dictionaries should be interpreted to have the same meaning as that in the context of the related art. Unless clearly defined in this specification, they should not be interpreted in an idealized or overly formal sense.

[0135] Hereinafter, with reference to ​ and ​ , the laser reflow soldering apparatus of the present invention will be described in detail.

[0136] ​ As an example diagram showing the overall structure of the laser reflow soldering apparatus of the present invention, ​ is ​ a structural block diagram.

[0137] As ​ and ​ shown, the laser pressing head module 300 of the laser reflow soldering apparatus of the present invention includes: one or more multi-laser modules 310, 320 for irradiating a laser in the form of a surface light source to a welding object 11 supported and transferred by a stage 111, the stage 111 having a structure capable of applying heat downward and formed with a porous material or a vacuum hole; a light-transmissive pressing member 100 independently provided separately from the laser modules 310, 320 for transmitting the laser in the form of a surface light source; and a protective film 200 for protecting the light-transmissive pressing member 100 from contamination.

[0138] First, the multi-laser modules 310, 320 (for example, the dual-laser module of an embodiment of the present invention) convert the laser generated from a laser oscillator and transmitted through an optical fiber into a surface light source to irradiate the welding object 11. The laser modules 310, 320 may include: a beam shaper (refer to ​ ) for converting the laser in the form of a spot into a surface light source; and an optical unit (refer to ​), disposed below the above-mentioned beam shaper, such that the surface light source emitted from the beam shaper irradiates the irradiation area of the welding object 11, and a plurality of lens modules are mounted inside the lens barrel at appropriate intervals from each other.

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

[0140] The laser pressing head module 300 of the laser reflow soldering device of the present invention includes: a light-transmissive pressing member 100 for pressing the welding object 11; and laser modules 310 and 320 for irradiating the welding object 11 with laser light in the form of a surface light source. The light-transmissive pressing member 100 and the laser modules 310 and 320 are separated from each other in an independent manner. Therefore, in the state where the light-transmissive pressing member 100 presses the welding object 11, after moving the laser modules 310 and 320 to a plurality of irradiation positions for irradiating the welding object 11, by driving, the tact time for one welding object 11 is shortened and the overall welding work for a plurality of welding objects 11 is speeded up.

[0141] In this case, the above-mentioned light-transmissive pressing member 100 is moved to the working position or the standby position by a light-transmissive pressing member transfer unit (not shown) having a specified form. As an example, the light-transmissive pressing member transfer unit can lower or raise the light-transmissive pressing member 100, or lower or raise it after moving left or right.

[0142] And, although not shown, the laser pressing head module 300 of the laser reflow soldering device of the present invention further includes a control unit (not shown), which controls the operation of the light-transmissive pressing member transfer unit by using data input from a pressure sensor (not shown) or a height sensor (not shown).

[0143] The above-mentioned pressure sensor and height sensor can be provided on the light-transmissive pressing member 100 and the table 111 for supporting the light-transmissive pressing member transfer unit and the welding object. For example, the control unit receives data from the pressure sensor to control the light-transmissive pressing member so that the pressure reaches the target value, and can receive data from the height sensor to control the light-transmissive pressing member transfer unit to reach the target value of the height.

[0144] And, a support unit (not shown) supports the light-transmissive pressing member transfer unit (not shown) in a movable manner. As an example, the above-mentioned support unit can be a pair of vertical frames, extending in parallel with the table 111, and should be interpreted as including a structure that supports the light-transmissive pressing member transfer unit in a manner that can move along the x-axis, y-axis, or z-axis.

[0145] The laser pressurizing head module 300 of the laser reflow soldering device of the present invention may include: one or more actuators for applying pressure to the light-transmissive pressurizing member 100; one or more pressure sensors for detecting the pressure applied to the light-transmissive pressurizing member 100; and one or more height sensors for detecting the height of the light-transmissive pressurizing member. For example, the pressure sensor may be one or more load sensors, and the height sensor may be a linear encoder.

[0146] The pressure applied to the soldering object is adjusted by the above pressure sensor. In the case of a large area, it can be controlled by multiple actuators and multiple pressure sensors to transfer the same pressure to the soldering object. Moreover, technical data is provided by one or more height sensors to confirm the height position value when the soldering object is soldered or to find a more accurate soldering height position. When performing a process that requires maintaining a specified height interval, a function capable of precisely controlling the height is executed.

[0147] Moreover, the light-transmissive pressurizing member 100 may be made of a base material for transmitting the laser output by the laser modules 310 and 320. The base material of the light-transmissive pressurizing member 100 may be any light beam transmissive material.

[0148] For example, the base material of the light-transmissive pressurizing member 100 may be one of quartz, sapphire, fused silica glass, or diamond. However, the physical properties of the light-transmissive pressurizing member made of quartz material are different from those of the light-transmissive pressurizing member made of sapphire. For example, in the case of irradiating a 980 nm laser, the transmittance of the light-transmissive pressurizing member made of quartz material is 85% - 99%, and the measured temperature of the soldering object is 100°C. On the contrary, the transmittance of the light-transmissive pressurizing member made of sapphire is 80% - 90%, and the measured temperature of the soldering object is 60°C.

[0149] That is, in terms of light transmittance and heat loss required for soldering, the performance of quartz is superior to that of sapphire. However, during the development of the laser reflow soldering device, the inventors of the present application found through repeated tests on the light-transmissive pressurizing member 100 that when laser soldering, the light-transmissive pressurizing member 100 made of quartz material has problems such as cracks or unqualified soldering quality due to burning on the bottom surface. This is because when laser soldering, as gas adheres to the bottom surface of the light-transmissive pressurizing member 100, the heat source of the laser is concentrated on the gas adhesion part, resulting in an increase in thermal fatigue.

[0150] In order to prevent damage to the light-transmitting pressure member 100 made of quartz material and improve durability, a thin film coating can be formed on the bottom surface of the light-transmitting pressure member made of quartz material. The thin film coating formed on the bottom surface of the light-transmitting pressure member 100 can be a commonly used optical coating, for example, a dielectric coating, a silicon carbide coating, or a metal material coating.

[0151] As ​ shown, the laser pressing head module 300 of the laser reflow soldering device of the present invention may further include: a protective film 200 formed under the light-transmitting pressure member 100 to prevent gas generated during laser welding from adhering to the bottom surface of the light-transmitting pressure member 100; and a protective film transfer unit 210 for transferring the protective film 200.

[0152] The protective film transfer unit 210 can unwind the protective film 200 wound in a roll form by a reel-to-reel method and transfer it to one side. As an example, the maximum continuous use temperature of the protective film 200 is 300 °C or higher, and the minimum continuous use temperature is 260 °C or higher. It is preferably made of a material with excellent heat resistance. For example, the protective film 200 can be made of polytetrafluoroethylene resin (commonly known as "Teflon resin"; PTFE, Polytetrafluoroethylene) or soluble polytetrafluoroethylene resin. Soluble polytetrafluoroethylene resin (PFA, Per Fluoro Alkylvinyether copolymer), as a product to improve the heat resistance related to fluorinated ethylene propylene resin, has a maximum continuous use temperature of 260 °C and belongs to the same high-performance resin as polytetrafluoroethylene resin.

[0153] ​ is a conceptual diagram of a single laser beam module of a laser reflow soldering device according to an embodiment of the present invention, ​ is a conceptual diagram of a dual laser beam module of a laser reflow soldering device according to another embodiment of the present invention.

[0154] Referring to the above ​ , in an embodiment of the present invention, a single laser module 310 is provided, whereby a single laser beam is irradiated onto a printed circuit board (PCB, Printed Circuit Board). According to an embodiment, the printed circuit board can be a flexible printed circuit board (Flexible PCB).

[0155] Referring to ​ , in this case, the laser beam irradiated through the first laser module 310 is irradiated onto the substrate in a deformed state of a square beam shape, and the intensity of the laser beam is homogenized.

[0156] On the other hand, referring to ​, in a further embodiment of the present invention, the multi-laser module includes a first laser module 310 and a second laser module 320. At the position of the electronic component attached to the welding object 11, the first laser module and the second laser module irradiate a homogenized overlapping laser beam in an overlapping state.

[0157] In ​ , the first laser beam is square-shaped and the second laser beam is circular. However, both laser beams can also be square-shaped. Also, the first laser beam and the second laser beam can be irradiated simultaneously. After preheating the welding object 11 with the first laser beam, the second laser beam can also be irradiated sequentially.

[0158] ​ It is a structural diagram of the dual-laser beam module of the laser reflow soldering device according to a further embodiment of the present invention.

[0159] In ​ , each laser module 310, 320, 330 respectively includes: laser oscillators 311, 321, 331, which are respectively provided with cooling devices 316, 326, 336; beam shapers 312, 322, 332; optical lens modules 313, 323, 333; driving devices 314, 324, 334; control devices 315, 325, 335; and power supply units 317, 327, 337.

[0160] Hereinafter, in order to avoid repeated description of each laser module having the same structure, unless necessary, the description will be mainly made with the first laser module 310 as the main.

[0161] The laser oscillator 311 generates a laser beam having a wavelength and output power within a specified range. As an example, the laser oscillator can be a laser diode (LD, Laser Diode) or a rare-earth-doped fiber laser or a rare-earth-doped crystal laser having a wavelength of "750 nm to 1200 nm" or "1400 nm to 1600 nm" or "1800 nm to 2200 nm" or "2500 nm to 3200 nm", etc. Differently, it can also include a medium for emitting alexandrite laser having a wavelength of 755 nm or a medium for emitting neodymium-doped yttrium aluminum garnet (Nd:YAG) laser having a wavelength of 1064 nm or 1320 nm.

[0162] The beam shaper 312 converts the spot-shaped laser generated from the laser oscillator and transmitted through the optical fiber into an area beam with a flat surface. The beam shaper 312 may include a square light pipe, a diffractive optical element (DOE), or a micro-lens array (MLA).

[0163] The optical lens module 313 irradiates the electronic components and the irradiation area mounted on the printed circuit board by adjusting the shape and size of the laser beam converted into the area beam shape by the beam shaper. The optical lens module forms an optical system by combining multiple lenses. Hereinafter, the specific structure of such an optical system will be described with reference to ​ the detailed description of the specific structure.

[0164] The driving device 314 is used to move the distance and position of the laser module relative to the irradiation surface. The control device 315 adjusts the beam shape, beam area size, beam clarity, and beam irradiation angle when the laser beam reaches the irradiation surface by controlling the driving device 314. In addition to the driving device 314, the control device 315 can also comprehensively control the various operations of the laser module 310.

[0165] On the other hand, the laser output adjustment unit 370 controls the amount of power supplied to each of the laser modules 310, 320, and 330 by the power supply units 317, 327, and 337 corresponding to each laser module based on a program received through the user interface or a preset program. The laser output adjustment unit 370 controls each of the power supply units 317, 327, and 337 based on the information on the reflux state of each component, each area, or the whole on the irradiation surface received from one or more camera modules 350. Differently, the control information of the laser output adjustment unit 370 is transmitted to the control devices 315, 325, and 335 of each laser module 310, 320, and 330, and each control device 315, 325, and 335 can also provide a feedback signal for controlling the corresponding power supply unit 317. And different from ​ , power is also distributed to each laser module by one power supply unit. In this case, the laser output adjustment unit 370 should control the power supply unit.

[0166] In the case of implementing the laser overlapping mode, the laser output adjustment unit 370 controls each of the laser modules 310, 320, 330 and the power supply units 317, 327, 337 such that the laser beams of the respective laser modules 310, 320, 330 have a required beam shape, beam area size, beam clarity, and beam irradiation angle. Except for the case where the first laser module 310 is used to preheat the area around the welding destruction object position and the second laser module 320 is used to additionally heat a narrower reflow object area, the laser overlapping mode is also applicable to the case where the required temperature curve of each laser module is controlled by appropriately distributing the preheating function and the additional heating function among the first laser module 310, the second laser module 320, and the third laser module 330.

[0167] On the other hand, in the case where one laser light source is distributed to each laser module, the laser output adjustment unit 370 may have a function for simultaneously adjusting the power and phase of the distributed laser beams. In this case, the beam flatness can be significantly improved by inducing destructive interference between the laser beams by controlling the phase, thereby further improving the energy efficiency.

[0168] On the other hand, in the case of simultaneously implementing the processing mode at multiple positions, the laser output adjustment unit 370 makes the partial laser beams or all laser beams from each laser module different by controlling one of the beam shape, beam area size, beam clarity, beam irradiation angle, and beam wavelength of each laser beam. At this time, in the case where one laser light source is distributed to each laser module, the laser output adjustment unit 370 may have a function for simultaneously adjusting the power and phase of the distributed laser beams.

[0169] With this function, the laser beam size and output can be adjusted to perform the bonding or removal of the bonding between multiple electronic components and the substrate within the irradiation surface. In particular, in the case of removing damaged electronic components on the substrate, minimizing the area of the laser beam to the corresponding electronic component area can minimize the heat generated in the adjacent other electronic components and normal electronic components on the substrate due to the laser beam. Thus, only the damaged electronic components to be removed can be removed.

[0170] On the other hand, in the case where the plurality of laser modules respectively emit laser beams having different wavelengths, the laser module can be a single laser module having wavelengths that can be effectively absorbed by the plurality of material layers included in the electronic component (for example, EMC layer, silicon layer, solder layer). Thus, the laser welding destruction device of the present invention can selectively increase the temperature of the electronic component and the temperature of the printed circuit part or an intermediate bonding material such as solder, which is a connection material between the electrodes of the electronic component, to achieve an optimal attaching or bonding process and a detaching or debonding process. Specifically, the laser beam is made to transmit through both the EMC mold layer and the silicon layer of the electronic component, thereby absorbing all the energy of each laser beam. Or, in the case where it does not transmit through the EMC mold layer, heat can also be transferred to the solder part under the electronic component by heating the surface of the electronic component.

[0171] On the other hand, by applying the above function, after preheating with one or more first laser beams to bring a specified area of the substrate including the area of the electronic component to be reflowed and its surroundings to a specified temperature, the area of the electronic component to be reflowed is selectively heated with one or more second laser beams so that its temperature reaches the reflow temperature at which the solder melts. For example, by utilizing this selective heating effect, the present invention can also be used as a rework device for effectively removing electronic components from the substrate.

[0172] ​ The structure diagram of the dual laser beam module of the laser reflow soldering device according to another embodiment of the present invention is applicable to the laser optical system.

[0173] ​ As the simplest-structured optical system applicable to the present invention, if the laser beam released from the beam transmission optical fiber 410 is focused by the convex lens 420 and incident on the beam shaper 430, the beam shaper 430 converts the laser beam in a point form into a flat-top surface light source A1 in a planar form. As the square laser beam A1 output from the beam shaper 430 is magnified to a desired size by the concave lens 440, the magnified surface light source A2 will irradiate the imaging surface S.

[0174] ​ The structure diagram of the laser optical system according to another embodiment of the present invention.

[0175] As the surface light source B1 of the beam shaper 430 is magnified to a specified size by the concave lens 440, it becomes the surface light source B2 that irradiates the first imaging surface S1. When further magnifying the use of such a surface light source B2, the boundary of the edge portion of the surface light source B2 may become unclear due to further magnification. Therefore, in order to obtain irradiated light with a clear edge on the final irradiation surface at the second imaging surface S2 as well, a mask 450 is provided on the first imaging surface S1 to trim the edge.

[0176] As the surface light source passing through the mask 450 is reduced (or magnified) and adjusted to a desired size by passing through the zoom lens module 460 composed of a combination of one or more convex lenses and concave lenses, a square irradiated light B3 is formed on the second imaging surface S2 where electronic components are arranged.

[0177] ​ This is a structural diagram of a laser optical system according to another embodiment of the present invention.

[0178] After the square surface light source C1 of the beam shaper 430 is magnified to a specified size by the concave lens 440, it passes through at least a pair of cylindrical lenses 470. For example, it is magnified (or reduced) along the x-axis direction to C2, and then passes through at least a pair of cylindrical lenses 480 again. For example, it is reduced (or magnified) along the y-axis direction and is converted into a rectangular surface light source C3.

[0179] Among them, the cylindrical lens is in a form where the cylindrical shape is cut along the length direction, and the laser beam is enlarged or reduced in a form where each lens is arranged along the up and down direction. On the surface where the cylindrical lens is arranged, the lens adjusts the laser beam along the x-axis direction or the y-axis direction in a manner of being arranged along the x-axis direction and the y-axis direction.

[0180] Next, the surface light source C3 is magnified (or reduced) and adjusted to a desired size by passing through the zoom lens module 460 composed of a combination of one or more convex lenses and concave lenses, and a rectangular irradiated light C4 is formed on the second imaging surface S2 where electronic components are arranged.

[0181] ​ This is a structural diagram of a laser optical system according to another embodiment of the present invention.

[0182] Compared with ​ the optical system, ​ the optical system includes a structure for trimming the edge of the laser beam using a mask. Therefore, it should be understood that compared with ​ the situation, the obtained final surface light source D5 has a clearer edge.

[0183] ​ This is a perspective view of the main part showing the bracket unit structure of the laser pressing head module of the present invention for a brief illustration.

[0184] Referring to ​ , the bracket unit 500 of the present invention includes: a lower plate 510, into which the lower part of the flat light-transmissive pressing member 100 is inserted and placed; and a mask plate 520, which is inserted and coupled to the upper part of the light-transmissive pressing member 100.

[0185] Moreover, square through-holes 510a and 520a are respectively formed in the central parts of the lower plate 510 and the mask plate 520. Therefore, when the light-transmissive pressing member 100 is in a state of being inserted and placed on the lower plate 510, it should be understood that the bottom surface 102 of the pressing member 100 is exposed downward due to the through-hole 510a of the lower plate 510.

[0186] On the other hand, in the above state, as the mask plate 520 is inserted and coupled to the upper surface of the light-transmissive pressing member 100, the central part of the upper surface of the light-transmissive pressing member 100 is installed in a state of being exposed upward through the through-hole 520a of the mask plate 520.

[0187] ​ It is a main part cross-sectional view for briefly showing the bracket unit structure and working state of the laser pressing head module of the present invention.

[0188] Referring to ​ , if the light-transmissive pressing member is irradiated with laser by the multi-beam laser modules 310 and 320 located above in a state of being installed between the lower plate and the mask plate, the laser beam can be transmitted downward through the through-hole 520a of the mask plate 520 and the light-transmissive pressing member 100.

[0189] In this case, the left and right corner parts of the bottom surface of the lower plate 510 have a shape gradually forming an arc, in order to prevent the protective film 200 from being torn or scratched when the protective film 200 located below the light-transmissive pressing member is pressed due to the downward movement of the light-transmissive pressing member, through the arc-shaped corners of the lower plate 510.

[0190] Moreover, as described above, the protective film 200 is pulled and wound by the protective film transfer parts 210 arranged on the left and right sides of the protective film 200. In this case, since the left and right corner parts of the bottom surface of the lower plate 510 gradually form an arc, the protective film 200 can be conveyed without being damaged by the corner parts.

[0191] As described above, in a state where a plurality of electronic components disposed on a substrate 11 to be welded are simultaneously pressed at a specified depth, the light-transmissive pressing member 100 irradiates a laser beam through the upper multi-laser modules 310 and 320. Thus, the solder located below the electronic components of the welding object 11 is melted by the above laser beam, and laser reflow soldering is performed.

[0192] Thereby, the above laser beams overlap with each other to form a homogenized laser beam, and the heat energy can be evenly transferred to the solder located below the electronic components of the welding object 11 through the through holes 520a of the mask plate 520 and the through holes 520a of the light-transmissive pressing member 100 and the lower plate 510.

[0193] In this case, when the above overlapping laser beam irradiates the surrounding substrate portion other than the electronic components, the surrounding portion of the substrate may be damaged by the heat energy of the laser beam. Therefore, it is necessary to irradiate only the electronic components of the welding object 11. For this purpose, in order to perform precise pressing and laser reflow soldering only on the electrode fittings of the above welding object 11, preferably, the area of the square through holes 520a of the mask plate 520 and the area of the pressing surface 102 of the light-transmissive pressing member 100 should be designed considering the transmission path and overlapping area of the laser beam.

[0194] ​ A perspective view showing mainly the probe unit structure and working state of the laser pressing head module of the present invention briefly.

[0195] The main feature of the present invention is that the mask plate 520 and the light-transmissive pressing member 100 can be replaced corresponding to various sizes of the substrate. Therefore, the light-transmissive pressing member 100 and the mask plate 520 can be replaced according to the shape and area of the substrate of different sizes or the electronic components disposed on the above substrate. In this case, according to the operator's requirements, an appropriate size is selected from the pre-prepared light-transmissive pressing member 100 and mask plate 520 for replacement to obtain pressing surfaces of different sizes. Subsequently, as ​ shown, the flatness is measured by piercing each corner portion of the upper surface of the light-transmissive pressing member 100 through the probe unit 600.

[0196] The above probe unit 600 may include: a probe 610 in the shape of a needle ejector; a probe transfer portion 620 for horizontally or vertically transferring the above probe; and a probe bracket 630 for supporting the above probe and transfer portion.

[0197] Accordingly, when an operator replaces the light-transmissive pressing member 100 and the mask plate 520 of different sizes to process substrates of different sizes, as the probe 610 is moved along the horizontal or vertical direction, the flatness of the light-transmissive pressing member 100 can be measured by sequentially piercing through four or more corner positions (denoted as X) on the upper surface of the light-transmissive pressing member 100.

[0198] ​ A side view briefly showing the vertical transfer portion structure and working state of the laser pressing head module according to an embodiment of the present invention.

[0199] Hereinafter, with reference to ​ , the vertical transfer portion structure and working state of the laser pressing head module will be described.

[0200] According to an embodiment, the vertical transfer portion may include: a stamping bracket 720 provided at four corner portions of the light-transmissive pressing member 100 and the bracket unit 500; a pressing cylinder 730 provided above the stamping bracket; a vertical driving portion for applying a driving force in the vertical direction to the stamping bracket 720; a ball screw 750 and a motor 760; and a guiding member 770 for guiding the linear movement of the stamping bracket 720.

[0201] Therefore, before the welding object 11 composed of a substrate and a plurality of electronic components is placed below the light-transmissive pressing member 100, the light-transmissive pressing member 100 and the bracket unit 500 are moved upward by driving the motor 760 of the vertical transfer portion. After the welding object 11 is placed, the light-transmissive pressing member 100 and the bracket unit 500 are moved downward again by driving the motor 760 to wait for pressing. Subsequently, the light-transmissive pressing member 100 presses the welding object 11 vacuum-adsorbed on the electrostatic chuck 940 through the operation of the pressing cylinder 730.

[0202] On the other hand, a heating block 942 for preheating the welding object 11 to a specified temperature is provided below the electrostatic chuck 940. Therefore, while the welding object 11 is being transported for laser reflow soldering treatment in a state where the welding object 11 is placed on the electrostatic chuck 940, the welding object 11 is continuously preheated. For example, the temperature for preheating the welding object 11 can be set to less than 200 °C. Preferably, the temperature should be set to a level that does not cause thermal damage to the substrate or the like due to preheating.

[0203] On the other hand, as ​As shown, based on the flatness measurement result of the light-transmissive pressing member 100 by the probe unit 600, when it is determined that the above light-transmissive pressing member 100 tends to either side, that is, in the case of unevenness, with the fine driving of the above vertical transfer unit, the support unit 500 is transferred upward or downward to adjust the flatness of the light-transmissive pressing member 100.

[0204] More specifically, based on the flatness measurement result of the light-transmissive pressing member 100 by the above probe unit 600, when it is determined that any one of the four corners of the upper surface of the above light-transmissive pressing member 100 is located at a lower position because it tends to one side more than the other corners, as the motor 760 at the corner part located at the above lower position operates, the overall flatness of the above light-transmissive pressing member 100 is adjusted by finely lifting the corner of the above support unit 500 upward.

[0205] In this case, regardless of the power supply state, the absolute position value of each corner part of the support unit 500 can be always maintained by setting an absolute encoder in the above motor 760. Preferably, the flatness adjustment process of the above light-transmissive pressing member 100 should be automated through the setting of the control unit.

[0206] ​ To briefly show a perspective view of the main part of the vertical transfer unit structure and working state of the laser pressing head module according to another embodiment of the present invention, ​ For ​ main part side cross-sectional view.

[0207] Hereinafter, with reference to the drawings, the local structure of the laser pressing head module according to an embodiment of the present invention, and the working relationship between pressing and laser beam irradiation will be described in detail.

[0208] Referring to the above drawings, the pressing head of the present invention includes a light-transmissive pressing member 100 for pressing an electronic component as the welding object 11 so that the laser beams irradiated from the laser sources 310 and 320 are transmitted. In this case, the above light-transmissive pressing member 100 is inserted and hung in the through hole of the support unit 500 in a replaceable manner. The support unit 500 is in a plate shape, and the through hole is formed in the central part of the support unit 500.

[0209] The above support unit 500 can be circular or polygonal (refer to ​ , ​ ), however, in ​ and ​ , an octagon will be described.

[0210] According to an embodiment, stamping units 700 are respectively pivotally coupled to three positions P1, P2, and P3 around the edge of the octagonal support unit 500. At this time, if the positions pivotally coupled to the stamping units are connected by a dotted line L, a triangle is formed.

[0211] In this case, the virtual triangle connecting the three positions of the support unit 500 may be an equilateral triangle. Preferably, the centroid G of the virtual triangle is the same as the centroid G of the light-transmitting pressing member 100.

[0212] The reason for designing three pivot coupling positions P1, P2, and P3 around the edge of the support unit 500 is that when connecting the pivot coupling positions P1, P2, and P3, it is difficult to form a stable triangular structure by pivotally coupling two stamping units (i.e., the line segment connecting two points cannot form an area). Therefore, in order to minimize the number of pivot coupling positions required to control flatness and construct pivot coupling positions with a stable virtual triangle, it is necessary to construct three precisely symmetric pivot coupling positions P1, P2, and P3 on the support unit 500.

[0213] On the other hand, referring to ​ , the stamping unit 700 includes: a stamping bracket 720 having a predetermined height and shape; a pressing cylinder 730 installed at the upper end of the stamping bracket to press the support unit 500 downward with a preset pressure; and a bearing joint 780, one end of which is coupled to the cylinder rod 731 of the pressing cylinder 730, and the other end of which is pivotally coupled to one of the three pivot coupling positions P1, P2, and P3 of the support unit 500 in a rotatable manner. In this case, the pressing cylinder may employ a precision pneumatic cylinder (precision work cylinder) capable of finely setting and adjusting the pressure in units of kgf.

[0214] In this case, pressure sensors 740 are respectively provided at the ends of the cylinder rods 731 of the pressing cylinders 730.

[0215] As an example, the pressure sensor 740 may be a load sensor. As the cylinder rods of the respective pressing cylinders 730 are pulled out and press the respective pivot coupling positions of the support unit 500, it continuously measures to detect whether a pressure above an appropriate pressure is consumed and feeds back to a control unit (not shown).

[0216] On the other hand, joint fastening parts 510 are respectively provided at the three pivot coupling positions of the support unit 500, and each of the joint fastening parts 510 is pivotally coupled to the bearing joint 780 in a rotatable manner.

[0217] Therefore, as the cylinder rod 731 of the pressurizing cylinder 730 is pushed in or pulled out, the bearing joint 780 pivotally coupled to the end of the cylinder rod 731 moves along the vertical direction, and thus, the joint fastening part 510 and the bracket unit 500 that are rotatably coupled to the bearing joint 780 also move together.

[0218] Therefore, the bracket unit 500 can be tilted and driven by adjusting the pushing length and pulling length of the cylinder rod 731 of each of the pressurizing cylinders 730, and thus, the pressure can be precisely adjusted by adjusting the contact height of the bracket unit 500.

[0219] Moreover, the end of the joint fastening part 510 is caught by the stopper 790 provided at the lower end of the stamping bracket 720. Therefore, the weight acting on the lower bracket unit 500 is offset by the stopper 790, and at the same time, it serves to maintain flatness when the bracket unit 500 is vertically transferred.

[0220] In addition, a vertical transfer part is provided on one side of the stamping bracket 720 to lift and lower the stamping bracket along the vertical direction.

[0221] Hereinafter, the structure of the vertical transfer part will be described according to an embodiment. The vertical transfer part may include: a stamping bracket 720 provided at three shaft coupling positions of the light-transmissive pressurizing member 100 and the bracket unit 500, respectively; a pressurizing cylinder 730 provided above the stamping bracket; a ball screw 750 and a motor 760 for applying a driving force in the vertical direction to the stamping bracket 720; and a guiding member 770 for guiding the linear movement of the stamping bracket 720.

[0222] According to the above structure, it should be understood that as the bracket unit 500 moves downward, the light-transmissive pressurizing member 100 mounted on the bracket unit 500 also moves downward together, and presses the electronic component 11b located therebelow.

[0223] Moreover, since the flatness of the bracket unit 500 may have an error due to vibrations generated during the reflow process or vibrations generated when replacing the light-transmissive pressurizing member 100, it is preferably initialized to zero after a predetermined period or when replacing the light-transmissive pressurizing member 100 to reset the flatness.

[0224] ​ It is a top view of the main part of the bracket unit of the laser pressurizing head module according to an embodiment of the present invention, which is formed in an octagon.

[0225] First, the shape of the bracket unit of the present invention can be polygonal, basically a triangle connecting three shaft coupling positions P1, P2, and P3. More specifically, in order to achieve geometric symmetry, the dotted line lengths connecting the three shaft coupling positions P1, P2, and P3 to the intermediate centroid G can be made the same to form an equilateral triangle.

[0226] And, in ​ In an illustrated embodiment, since the square light-transmitting pressing member should be placed and housed inside the polygonal bracket unit, the shape of the bracket unit can be octagonal to provide a larger area than the light-transmitting pressing member to sufficiently house the square light-transmitting pressing member.

[0227] Therefore, the bracket unit of the present invention is not limited to ​ the octagon shown, and can be polygons of various shapes. For example, it can be a triangle, square, octagon, etc. that planar includes a virtual triangle connecting three shaft coupling positions P1, P2, and P3.

[0228] On the other hand, ​ This is a top view of the main part where the bracket unit of the laser pressing head module according to another embodiment of the present invention is formed into a circle.

[0229] And, the shape of the bracket unit of the present invention can be polygonal, and according to another embodiment, it can also be formed into a circle.

[0230] Therefore, as ​ shown, when the bracket unit is circular, since the dotted line lengths connecting the three shaft coupling positions P1, P2, and P3 around the edge of the bracket unit to the intermediate centroid G are the same, the bracket unit achieves geometric symmetry. Thus, high flatness is maintained using only at least three shaft coupling positions P1, P2, and P3, and each shaft coupling position can be precisely pressed and controlled respectively.

[0231] Thus, the above-mentioned pressing head of the present invention uses the light-transmitting pressing member 100 with a specified area to simultaneously press a plurality of electronic components 11b and irradiate the light-transmitting laser beam, thereby performing a one-time reflow soldering process. Therefore, compared with the existing method of placing small light-transmitting pressing members on each electronic component and pressing by weight, it has the effect of greatly improving precision and productivity.

[0232] Moreover, a Seiko air cylinder that can precisely adjust the pressure in units of Kgf can be used as the above-mentioned pressurizing air cylinder 730 to precisely adjust the pressure. Thus, the operator can adjust the set pressure of the above-mentioned pressurizing air cylinder 730 in different ways according to various variable factors such as the bending state of the flexible printed circuit board. Therefore, compared with the prior art, the present invention can easily adjust the pressure balance applied to the multiple electronic components 11b disposed below the large-area light-transmissive pressurizing member 100.

[0233] On the other hand, when a pressure higher than the set pressure different from the preset pressure is applied to each of the above-mentioned pressurizing air cylinders 730, the pressure sensor 740 combined with the end of the cylinder rod 731 of the above-mentioned pressurizing air cylinder 730 will detect it and feedback it to the control unit (not shown).

[0234] Therefore, if a pressure above a specified value is detected, the control unit performs an automatic balance process of adjusting it to the set pressure value, or an alarm can be sent to enable the operator to easily manually adjust the set pressure of each of the above-mentioned pressurizing air cylinders 730 according to requirements.

[0235] And, although not shown in ​ 、 ​ , the above-mentioned bracket unit 500, light-transmissive pressurizing member 100, and stamping unit 700 can be disposed on the ​ shown light-transmissive pressurizing member transfer unit 140 and support unit 150. As an example, the above-mentioned light-transmissive pressurizing member transfer unit 140 can be vertically transferred in the up and down direction through a vertical transfer unit (for example, a motor and a ball screw device). As an example, the support unit 150 can be a vertical frame device.

[0236] Therefore, when the electronic components and substrates to be welded are put in, the above-mentioned bracket unit 500, light-transmissive pressurizing member 100, and stamping unit 700 are vertically transferred upward, so that the welding object 11 is put in the position directly below the light-transmissive pressurizing member 100. After the welding object 11 is put in the position directly below the pressurizing member 100, the above-mentioned bracket unit 500, light-transmissive pressurizing member 100, and stamping unit 700 are vertically transferred downward again to a position close to the welding object 11, so as to be in a standby state for pressurization.

[0237] ​ And ​ is a main part perspective view of the light-transmissive pressurizing member of the laser pressurizing head module of the present invention, ​ is a shape example diagram of the light-transmissive pressurizing member with a single pressurizing surface according to an embodiment of the present invention, ​ is a shape example diagram of the light-transmissive pressurizing member with a pressurizing surface divided in a manner corresponding to each electronic component according to another embodiment of the present invention.

[0238] Hereinafter, with reference to ​ and ​ , in the structure of the light-transmissive pressing member 100 according to an embodiment of the present invention, as shown in ​ , the light-transmissive pressing member 100 of the present invention has the following structure, that is, a pressing surface 102 with a specified area is formed to protrude on a square plate-shaped base material 101. Preferably, the area of the pressing surface 102 is designed according to the area of the welding object 11 to be processed by one-time laser reflow soldering to correspond to the processing area of the welding object 11.

[0239] In this case, the area of the pressing surface 102 is narrower than the area of the base material 101, and one or more stepped portions 101a are formed around the pressing surface 102. And, in addition to the pressing surface 102, a laser blocking layer 103 (shown in shadow) for preventing light leakage of the laser beam is also formed on the side surface of the base material 101, the bottom surface and the side surface of the stepped portion 101a.

[0240] On the other hand, with reference to ​ , in the structure of the light-transmissive pressing member 100 of the laser pressing head module according to another embodiment of the present invention, although a single pressing surface 102 is formed in ​ , in ​ , in order to respectively contact and press a plurality of electronic components included in the welding object 11, the pressing surface 102 has a structure divided into a grid shape to correspond to the area of each electronic component. For this purpose, in the structure shown in ​ , the pressing surface 102 needs to be designed and processed to accurately correspond to the occupied area of each electronic component to be processed by laser reflow soldering.

[0241] In this case, as shown in ​ , in addition to the plurality of pressing surfaces 102 divided into a grid shape, a laser blocking layer 103 (shown in shadow) is also formed on the side surface of the base material 101, the bottom surface and the side surface of the stepped portion 101a.

[0242] Generally, the laser blocking layer 103 can be a special coating in various forms for absorbing or reflecting light. For example, it can be a composite layer composed of one or more of an Inconel coating, a scattering treatment layer in the form of frosted glass, or a high reflection (HR) coating for reflecting the laser beam. By coating the laser blocking layer 103, the laser beam passes through the pressing surface 102 of the light-transmissive pressing member 100 and only accurately irradiates the electronic components of the welding object 11, thereby preventing damage to the substrate caused by the laser beam irradiating the adjacent printed circuit board portion around the electronic components and the resulting damage.

[0243] ​ A working state diagram showing the state in which the light-transmissive pressing member of the present invention is mounted on the pressing head ​ is ​ an enlarged view of the main part of

[0244] Referring to the above ​ and ​ In the structure of the light-transmissive pressing member 100 of the present invention as described above, the pressing surface 102 protrudes and is formed on the bottom surface of the square substrate 101, and has an area smaller than the area of the above substrate. In this case, more than one stepped portion 131a is formed between the above substrate 101 and the pressing surface 102. As ​ shown, the above stepped portion 101a causes the light-transmissive pressing member 100 to be hung on the bracket unit 500 of the reflux device.

[0245] On the other hand, a silicon damping layer 104 may also be formed on the above pressing surface 102. Generally, according to the characteristics of the above flexible printed circuit board, the multiple electronic components configured on the printed circuit board that make up the welding object 11 are not completely flat and have their own curvature. Therefore, it should be understood that the respective electronic components are arranged at different heights along the curved surface of the above flexible printed circuit board on the horizontal line, rather than at the same height.

[0246] In this case, if the pressing surface 102 of the light-transmissive pressing member 100 simultaneously presses multiple electronic components located at different heights on the curved surface of the flexible printed circuit board for performing soldering treatment, the multiple electronic components located at the relative height position will be subjected to a greater pressure than the multiple electronic components located at the lower position. As a result, the solder in the lower part of the multiple electronic components located at the above height position cannot flow back normally due to the excessive pressure, thereby causing soldering defects.

[0247] For this reason, according to an embodiment of the present invention, a silicon damping layer 104 as a light-transmissive elastomer is additionally formed on the pressing surface 102. Thus, when the multiple electronic components located above are subjected to excessive pressure, the above silicon damping layer 104 performs a damping function to absorb a specified amount of excessive pressure.

[0248] On the other hand, if the above light-transmissive pressing member 100 presses the electronic components, a laser beam is irradiated from the first laser module 310 or the second laser module 320 located above the above light-transmissive pressing member 100. The above laser beam is irradiated onto the electronic components through the light-transmissive pressing member 100, thereby transferring the thermal energy for reflux.

[0249] Referring to the above ​, when the laser beam irradiates through the above-mentioned light-transmissive pressing member 100, since the laser-blocking layer 103 (shaded) is formed on the side surface of the base material 101, the bottom surface, and the side surface of the stepped portion 101a, as a result, the leakage of the laser beam to all parts other than the pressing surface 102 is blocked.

[0250] Moreover, in order to achieve uniform laser reflow soldering treatment in the present invention, when designing the light-transmissive pressing member 100, the shape and protruding height of the above-mentioned pressing surface 102 are mainly considered. For example, as ​ shown, if the pressing surface 102 is formed in a rectangular structure rather than a square structure, since the side area of the long side of the rectangle is larger than that of the short side, it can be predicted that the heat energy of the laser beam will be lost more quickly to the long side.

[0251] If such a heat loss phenomenon occurs, since the heat energy cannot be evenly transferred to the multiple electronic components pressed in the state of being arranged under the pressing surface 102, the possibility of soldering defects in the electronic components located at a relatively lower or relatively higher place than the appropriate soldering temperature is further increased. Therefore, according to the preferred embodiment, the bottom surface shape of the pressing surface 102 can be designed into a square structure so that the heat loss through the side surface of the pressing surface 102 is evenly achieved in the up, down, left, and right directions.

[0252] Moreover, even if the protruding height h of the side surface of the pressing surface 102 is formed too high, a large amount of heat loss may occur through the side surface of the above-mentioned stepped portion 101a. Therefore, most preferably, the protruding height h of the pressing surface 102 or the depth of the grid groove 102a recessed between the divided pressing surfaces 102 is minimized to within several millimeters (mm).

[0253] On the other hand, ​ For showing the schematic diagrams of various embodiments of the light-transmissive pressing member of the present invention, ​ shows the case where the corners of the pressing surface are not processed, ​ shows the case where the corners of the pressing surface are chamfered, ​ shows the case where the corners of the pressing surface are rounded.

[0254] Referring to ​ , ​ , ​ , as shown in the previous ​ shown, a protective film 200 is provided below the light-transmissive pressing member 100 of the present invention to prevent gas adsorption. In this case, as ​ shown, as the above-mentioned light-transmissive pressing member 100 moves downward, if the soldering object 11 is pressed, the above-mentioned protective film 200 will also be pressed by the light-transmissive pressing member 100. At this time, it can be understood that the protective film 200 is combined with the two side corner portions of the above-mentioned pressing surface 132.

[0255] However, as described above, when the protective film 200 repeatedly contacts the corners formed on both sides of the pressing surface 102, the problem that the above-mentioned protective film 200 is finally torn or damaged will occur.

[0256] Therefore, in order to avoid the above problems and to prevent the protective film from being damaged by the corners on both sides of the pressing surface 102, when designing the light-transmissive pressing member 100, additional matters should be considered, that is, as ​ shown, chamfering is performed on the corners on both sides of the pressing surface 102, or, as ​ shown, rounding is performed on the corners on both sides.

[0257] ​ To briefly show ​ a side cross-sectional view of the main part of the overall device structure of the laser pressing head module according to an embodiment of ​ For ​ a top view of the main part of ​ To magnify and show ​ a perspective view of the main part of the stamping unit of the laser pressing head module according to an embodiment of

[0258] Hereinafter, with reference to the drawings, the local structure of the laser pressing head module and the working relationship between pressing and laser beam irradiation will be described in detail according to an embodiment of the present invention.

[0259] First, with reference to ​ and ​ , the pressing head naphthalene light-transmissive pressing member 100 of the present invention is used to transmit the laser beam irradiated from the laser sources 310 and 320 in a state of pressing the electronic component 11b to be welded. At this time, the light-transmissive pressing member 100 is mounted in a hanging state in a through hole formed in the center of the plate-shaped support unit 500. Thus, as the support unit 500 moves downward, the light-transmissive pressing member 100 mounted on the support unit also moves downward together, thereby pressing the electronic component 11b located below it.

[0260] Moreover, each stamping unit 700 is adjacent to each corner portion of the support unit 500 in a non-contact state. First, the lower part of the support unit 500 is supported by the pressure balancer 710. The pressure balancer 710, as a buffer member, offsets the weights of the light-transmissive pressing member 100 and the support unit 500 by pressing in the opposite direction. As an example, it can be realized by an air cylinder or a spring.

[0261] Therefore, after the basic weights applied to the light-transmissive pressing member 100 and the support unit 500 are offset to zero (0) by the above-mentioned pressure balancer 710, the light-transmissive pressing member 100 is in a standby state for pressing.

[0262] On the other hand, referring to ​ , the other component structures of the above-mentioned stamping unit 700 will be described in detail. The above-mentioned stamping unit 700 includes: a stamping bracket 720, which is in an inverted U shape and surrounds each corner part of the bracket unit 500 in a non-contact state; pressing cylinders 730a, 730b, 730c, 730d, which are respectively fixedly arranged at the upper end of the above-mentioned stamping bracket; and a pressure sensor 740, which is arranged at the end of the cylinder rods of the above-mentioned pressing cylinders 730a, 730b, 730c, 730d.

[0263] In this case, as an example, the above-mentioned pressure sensor 740 can be a load sensor. As the cylinder rods of the above-mentioned pressing cylinders 730a, 730b, 730c, 730d are pulled out, when respectively pressing each corner part of the bracket unit 500, by continuously measuring it, it is detected whether a pressure above an appropriate pressure is consumed and feedback is given.

[0264] Therefore, as described above, the pressing head of the present invention simultaneously presses a plurality of electronic components 11b through the light-transmitting pressing member 100 having a specified area and irradiates the above-mentioned light-transmitting laser beam, thereby performing a one-time reflow soldering process. Therefore, compared with the conventional method of placing small light-transmitting pressing members on each electronic component and pressing them by weight, it has the effect of greatly improving productivity.

[0265] For this reason, the present invention can achieve large-area pressure adjustment by respectively arranging pressing cylinders 730a, 730b, 730c, 730d capable of independently setting pressure at each corner of the above-mentioned bracket unit 500. Moreover, as an example, the above-mentioned pressing cylinders 730a, 730b, 730c, 730d can adopt precision pneumatic cylinders (hereinafter, Seiko cylinders) capable of finely setting and adjusting the pressure in units of kgf. Thus, the operator can respectively adjust the set pressures of the above-mentioned pressing cylinders 730a, 730b, 730c, 730d in different ways according to various variable factors such as the bending state of the printed circuit board. Therefore, compared with the prior art, the present invention can easily adjust the pressure balance on the plane of the light-transmitting pressing member 100.

[0266] On the other hand, when a set pressure above the preset pressure is applied to each of the above-mentioned pressurizing cylinders 730a, 730b, 730c, and 730d, the pressure sensor 740 combined with the ends of the cylinder rods 731 of the above-mentioned pressurizing cylinders 730a, 730b, 730c, and 730d will detect it and feedback it to the control unit (not shown). Therefore, if a pressure above a specified value is detected, the control unit performs an automatic balance process to adjust it to the set pressure value, or an alarm can be sent to enable the operator to easily manually adjust the set pressure of each of the above-mentioned pressurizing cylinders 730a, 730b, 730c, and 730d as needed.

[0267] And, although not shown in ​ , the above-mentioned bracket unit 500, the light-transmissive pressurizing member 100, and the stamping unit 700 can be provided on the ​ shown light-transmissive pressurizing member transfer unit 140 and support unit 150. As an example, the above-mentioned light-transmissive pressurizing member transfer unit 140 can be vertically transferred in the up and down direction by a vertical transfer unit (for example, a motor and a ball screw device), and as an example, the support unit 150 can be an upright frame device.

[0268] Therefore, when the electronic component and the substrate as the welding object 11 are loaded, the above-mentioned bracket unit 500, the light-transmissive pressurizing member 100, and the stamping unit 700 are vertically transferred upward so that the welding object 11 is loaded at a position directly below the light-transmissive pressurizing member 100. After the welding object 11 is loaded at a position directly below the pressurizing member 100, the above-mentioned bracket unit 500, the light-transmissive pressurizing member 100, and the stamping unit 700 are vertically transferred downward again to a position close to the welding object 11, so as to be in a standby state for pressurization.

[0269] On the other hand, referring to ​ and ​ , in order to remove particulate contamination such as dust on the upper surface of the light-transmissive pressurizing member, an ionizer 800 is also provided above the above-mentioned bracket unit 500. As an example, the above-mentioned light-transmissive pressurizing member 100 is made of quartz material. Even if the process execution space of the present invention is a clean dust-free room environment, if particles accumulate more and more, accidents such as particle combustion may occur due to repeated laser beam irradiation.

[0270] Therefore, as the above-mentioned particle combustion occurs repeatedly for a long time, the upper surface of the light-transmissive pressurizing member 100 will gradually change color. As a result, cracks and other damages may finally occur to the light-transmissive pressurizing member 100. Therefore, it is necessary to prevent electrostatic generation on the upper surface of the light-transmissive pressurizing member 100 through the ionizer 800 to prevent particle adsorption in advance.

[0271] ​To show a three-dimensional view of the input area structure and working relationship of the welding object transfer module according to an embodiment of the present invention, hereinafter, with reference to ​ , the mechanical structure and working relationship of the input area (loading area) of the welding object of the present invention will be described.

[0272] First, the input area structure includes an input conveyor 910 for loading welding objects (as an example, placing a plurality of electronic components on a printed circuit board) to perform laser reflow soldering. The input conveyor 910 includes a conveyor frame 912 bent in an "┓" shape. On both upper sides of the conveyor frame 912, a pair of linear guide units 911 for inputting welding objects 11 into the conveyor are provided. The linear guide units 911 are coupled to the rotating shaft of a rail driving motor 913. And, a width adjustment motor 915 is provided on one side of the conveyor frame 912 to expand or contract the width of the input conveyor 910 to accommodate welding objects 11 of different sizes.

[0273] And, a horizontal transfer unit 920 is installed at one end of the conveyor frame 912. As the horizontal transfer unit 920 transfers along the horizontal direction, the conveyor frame 912 will also move along the horizontal direction together.

[0274] On the other hand, a preheating table 914 is provided on the upper part of the conveyor frame 912. Before the welding object 11 conveyed by the linear guide unit 911 is put into the laser reflow soldering area, during the period of staying above the preheating table 914, the welding object 11 is continuously preheated to a specified temperature (for example, 150 °C) so that the temperature can quickly and stably rise to the melting temperature of the solder (for example, 250 °C) through the laser beam irradiation during laser reflow soldering.

[0275] On the other hand, in order to make the input conveyor 910 move horizontally in a preheated state on the preheating table 914 and be put into the reflow soldering area, the welding object 11 needs to be accurately transferred to the vacuum chuck 940. In this case, with reference to ​ , a pickup unit 930 is further provided above the vacuum chuck 940. The pickup unit 930 includes: a vacuum adsorption pad 931 for adsorbing welding objects; a cylinder 932 for transferring the vacuum adsorption pad along the vertical direction; and a support frame 933 for fixing the vacuum adsorption pad 931 and the cylinder 932.

[0276] Thus, when the above-mentioned input conveyor 910 moves toward the vacuum chuck 940 side, the vacuum adsorption pad 931 of the above-mentioned pickup unit 930 moves upward by the drive of the cylinder 932. Subsequently, if the welding object 11 is located below the above-mentioned vacuum adsorption pad 931, then as the vacuum adsorption pad 931 moves downward, after adsorbing the welding object 11, it is moved upward again. Then, as the input conveyor 910 moves horizontally back to the original position, if it detaches from below the vacuum adsorption pad 931, the vacuum adsorption pad 931 will move downward again, thereby repeatedly performing the operation of placing the above-mentioned welding object 11 on the vacuum chuck 940.

[0277] Next, a horizontal movement unit is provided below the above-mentioned vacuum chuck 940. As an example, a linear motor 941 is provided, and through the operation of the above-mentioned linear motor 941, the above-mentioned vacuum chuck 940 and the welding object 11 are moved together to the laser reflow soldering processing area.

[0278] Also, a vision unit 934 is provided on one side of the above-mentioned vacuum chuck 940, which is used to continuously detect whether it is normally loaded in the input area, and to detect whether the welding object 11 is accurately placed and arranged on the vacuum chuck.

[0279] On the other hand, ​ is a perspective view showing the output area structure and working relationship of the welding object transfer module according to an embodiment of the present invention. Hereinafter, with reference to ​ the mechanical structure and working relationship of the output area (unloading area) of the welding object of the present invention will be described in detail.

[0280] The structure of the output conveyor 950 is substantially the same as that of the input conveyor 910 described above. The difference from the structure of the input conveyor 910 is that the output conveyor 950 does not have a preheating table 914 for preheating the welding object 11.

[0281] Therefore, if the welding object 11 that has completed the laser reflow soldering process is transferred to the output area (unloading area) while placed on the vacuum chuck 940, the pickup unit 970 adsorbs the welding object 11 on the vacuum chuck 940 in the reverse order during loading and transfers it to the output conveyor 950. Subsequently, the output conveyor 950 will move horizontally and unload the welding object 11 outside the device through the linear rail unit 951.

[0282] ​ and ​ is an example diagram showing the vacuum chuck unit structure and working relationship of the welding object transfer module of the present invention. ​ is a top view and a side cross-sectional view showing the structure of a porous adsorption plate according to an embodiment. ​ is a top view and a side cross-sectional view showing the structure of a porous adsorption plate according to another embodiment.

[0283] First, referring to ​ , in the structure of the vacuum suction cup 940 according to an embodiment of the present invention, a plurality of porous suction plates are formed on the upper surface. The porous suction plates are composed of a central suction plate 943 and an edge suction plate 944. The central suction plate 943 is rectangular and is used to suck the central part of the bottom surface of the welding object 11. The edge suction plate 944 surrounds the periphery of the central suction plate and is used to suck the edge part of the bottom surface of the welding object 11.

[0284] In this case, referring to the top view, if the welding object 11 with a specified area is placed on the porous suction plates 943 and 944, the welding object 11 is vacuum-sucked by suction units (not shown) such as air compressors provided in the central suction plate 943 and the edge suction plate 944, so that it is fixed in an extended state on the upper surface of the vacuum suction cup 940.

[0285] Moreover, referring to the side cross-sectional view, the central suction plate 943 and the edge suction plate 944 are spaced apart from each other with a specified interval. In this case, since the suction plate lifting unit 980 is provided below the central suction plate 943, the central suction plate 943 can, when necessary, have another embodiment structure in which the pickup units 930 and 970 are omitted in the structure of the above-described embodiment. That is, the central suction plate 943 can also directly receive the welding object 11 from the input conveyor 910. At this time, even if the central suction plate 943 rises upward to directly receive the welding object 11 from the input conveyor 910, receives the welding object 11 directly from the rail unit 911 of the input conveyor 910 and then descends downward again, the central suction plate 943 can fully achieve the object of the present invention.

[0286] In addition, a heating block 942 can be further provided directly below the central suction plate 943. The heating block 942 is the same as the preheating table 914 of the input conveyor 910 and is used to preheat the welding object 11 to a specified temperature during the process of transporting the welding object for performing laser reflow soldering treatment.

[0287] On the other hand, ​ shows the structure and working relationship of the porous suction plate according to still another embodiment of the present invention. The difference from the structure of the embodiment described through ​ is that, different from the porous material of the central suction plate, the edge suction plate 945 is made of aluminum material, and a plurality of suction holes 944a are further formed so as to more firmly suck the edge part of the bottom surface of the welding object 11 along the circumferential direction adjacent to the central suction plate 943 of the edge suction plate 945. Other structures and working relationships are the same as those of the embodiment described with reference to ​ , and thus, the detailed description will be omitted.

[0288] Moreover, as ​ and ​ shown, by adjusting the vacuum suction forces of the central suction plate 943 and the edge suction plates 944, 945 of the vacuum suction cup 940, the self-bending or wrinkling of the printed circuit board or flexible printed circuit board (Flexible PCB) of the welding object 11 can be stretched to a certain extent. Thus, not only is the vertical height of the multiple electronic components placed on the above substrate improved, but also the multiple electronic components are almost located at the same position. Therefore, during the laser reflow soldering process, problems such as defective processes caused by excessive pressure on specific electronic components can be improved.

[0289] ​ FIG. is a side view briefly showing the structure and working relationship of a multi-laser module according to another embodiment of the present invention. ​ FIG. is an enlarged perspective view showing the main part of the temperature sensor structure of ​ . ​ FIG. is an enlarged top view showing the main part of the welding object structure of ​ .

[0290] Hereinafter, with reference to ​ , the structure and working relationship of a multi-laser module according to another embodiment of the present invention will be described in detail.

[0291] First, with reference to ​ , a multi-laser module according to another embodiment of the present invention includes a pair of first laser modules 310 and second laser modules 320. An infrared temperature sensor 810 is disposed between the first laser module 310 and the second laser module 320 for measuring the temperature related to the laser beam overlappingly irradiated from the first laser module 310 and the second laser module 320.

[0292] On the other hand, beam analyzers 318, 328 are respectively disposed on the first laser module 310 and the second laser module 320 for continuously detecting the laser beam output, intensity, etc. of the first laser module 310 and the second laser module 320. As an example, in the structures of the beam analyzers 318, 328, part of the laser beam output via the laser beam paths of the first laser module 310 and the second laser module 320 is irradiated or transmitted to the beam analyzer, so that the power, intensity, etc. of the laser beam can be measured.

[0293] According to an embodiment, the infrared temperature sensor 810 can be a single infrared temperature sensor 810, and the single infrared sensor is used to measure the surface temperature value of the overlapping irradiation laser beam region 12 of the first laser module and the second laser module. In this case, the single infrared temperature sensor 810 measures the overall temperature distribution value of the overlapping irradiation laser beam region by sequentially measuring multiple positions in the overlapping irradiation laser beam region.

[0294] At this time, the measured temperature distribution values may not be uniform. As an example, in a position where the measured temperature value at one location is higher than the solder melting temperature, overflow soldering defects may occur due to overheating of the solder. On the contrary, in a case where the temperature is lower than the solder melting temperature, soldering defects such as insufficient melting and contact of the solder may occur.

[0295] Therefore, the present invention continuously measures the temperature of the overlapping irradiation area through the infrared temperature sensor 810 described above, and adjusts the power or intensity of each laser beam output from the first laser module 310 or the second laser module 320, the shape of the light beam, etc., thereby compensating the temperature distribution value in the overlapping irradiation area 12.

[0296] On the other hand, according to another embodiment of the present invention, a plurality of infrared temperature sensors 810 may also be included. Referring to ​ , as an example, the plurality of infrared temperature sensors of the present invention may include five temperature sensors 810#1, 810#2, 810#3, 810#4, 810#5. In a square configuration structure, one temperature sensor 810#1, 810#2, 810#3, 810#4 is respectively arranged at each corner part, and one temperature sensor 810#5 is arranged in the middle part. Thus, the five temperature sensors 810#1, 810#2, 810#3, 810#4, 810#5 irradiate infrared light beams simultaneously. In this case, as ​ shown, a plurality of electronic components 11b#1, 11b#3, 11b#7, 11b#9 located at each corner part of the square area 12 of the overlapping irradiation laser and the electronic component 11b#5 located in the middle part are irradiated with infrared light beams and the temperature is measured.

[0297] In this case, the above content does not limit the relevant positions and quantities of the electronic components 11b for which the temperature is measured, and the temperature of the substrate surface where no electronic component is arranged may also be measured. In order to obtain a more accurate temperature distribution value related to the overlapping irradiation laser beam area, it can be achieved by measuring the temperature values of a plurality of electronic components and the substrate.

[0298] On the other hand, as a method for compensating the above temperature distribution value, the temperature distribution value may also be compensated during the process of adjusting the irradiation angle and height of the first laser beam or the second laser beam.

[0299] ​ The state diagram showing the working relationship according to the process of the laser reflow soldering method of the present invention is as follows. Hereinafter, each process step of the laser reflow soldering method will be described in detail according to an embodiment.

[0300] First, ​To show a state diagram in which the light-transmissive pressing member 100 moves above the center line Cn+1, if the pressing surface 102 of the light-transmissive pressing member 100 is located on the center line Cn+1, the vision unit 934 captures a plurality of electronic components 11b located below the pressing surface 102 of the light-transmissive pressing member 100. In this case, when observing from the side as shown in ​ , it is determined whether the plurality of electronic components 11b are symmetrically arranged with respect to the center line Cn+1 of the pressing surface 102 of the light-transmissive pressing member 100.

[0301] That is, it is determined whether the arrangement shape of the plurality of electronic components 11b directly below the pressing surface 102 of the light-transmissive pressing member 100 corresponds to the area of the pressing surface 102. For example, as shown in ​ , in a state where the plurality of electronic components 11b are arranged in three columns, it is determined whether the plurality of electronic components 11b are symmetrically arranged left and right with respect to the center line Cn+1 of the pressing surface 102 to form 1.5 columns. Thus, when the pressing surface 102 of the light-transmissive pressing member 100 presses the range (area) where the plurality of electronic components 11b are arranged in three columns, uniform pressing can be achieved without the pressure being biased to either side.

[0302] Moreover, referring to the drawings, a plurality of electronic components 11b of the welding object 11 are arranged at positions to be welded together with the solder 11c on the upper surface of the substrate 11a. At this time, the substrate 11a is in a fixed state of being vacuum adsorbed by the lower vacuum chuck 340. In this case, since a heating block 942 is provided inside the vacuum chuck 940, the substrate 11a, the electronic components 11b, and the solder 11c, which are the welding object 11, are continuously preheated to a specified temperature. For example, preferably, the preheating temperature should be set lower than the melting temperature of the solder. For example, it can be maintained within a temperature range where no thermal damage occurs even if the substrate 11a and the electronic components 11b are exposed for a specified time or more, that is, less than 200°C.

[0303] In the case where the welding object 11 is not preheated in the above manner, it is necessary to rapidly heat the welding object 11 from room temperature to the melting temperature of the solder 11c only by using the thermal energy of the laser beam generated during the laser reflow soldering process. In this case, due to the rapid heating, there may be welding defects such as overflow in the solder 11c. Therefore, the temperature needs to be gradually increased, and the temperature can be gradually increased from the preheating temperature to the melting temperature of the solder 11c to stably melt the solder 11c and minimize welding defects. For example, among them, the melting temperature of the solder 11c may vary depending on the material of the solder. Generally, the melting temperature of solder paste can be 200°C or higher.

[0304] ​A state diagram showing the light-transmissive pressing member 100 being pressed and irradiated with a laser at the center line Cn+1, as ​ shown, when it is determined by the vision unit 934 that the center line Cn+1 of the pressing surface 102 of the light-transmissive pressing member 100 coincides with the center lines of a plurality of electronic components 11b to be welded, the light-transmissive pressing member 100 presses the electronic components 11b by moving downward.

[0305] In this case, a laser beam can be irradiated sequentially while the above-mentioned light-transmissive pressing member 100 is being pressed. For example, during the pressing process of the above-mentioned light-transmissive pressing member 100, the laser beam can be overlapped and irradiated on a plurality of electronic components 11b through a multi-laser module, a first laser module 310, and a second laser module 320 located above.

[0306] Thus, the welding object 11 is gradually heated from the preheating temperature to the melting temperature of the solder 11c by the overlapped laser beams irradiated above. As a result, as the solder 11c located below the plurality of electronic components 11b is melted, the welding of the electronic components 11b to the substrate 11a is completed (the height difference before and after welding is represented by ​ hc in

[0307] ​ A state diagram showing the light-transmissive pressing member moving upward above the center line Cn+2, ​ A state diagram showing the position of the light-transmissive pressing member calibrated based on the center line Cn+2', ​ A state diagram showing the light-transmissive pressing member being pressed and irradiated with a laser at the center line Cn+2'.

[0308] Referring to the above ​ , after completing the above laser reflow soldering process, the light-transmissive pressing member 100 will move to the next specified range, that is, it will move horizontally along the center line Cn+2' of a plurality of electronic components 11b in three columns in order to perform pressing and laser reflow soldering processes on the plurality of electronic components 11b in three columns. In this case, the vision unit 934 will photograph again the arrangement shape of the plurality of electronic components 11b arranged below the pressing surface 102 of the light-transmissive pressing member 100.

[0309] However, in this case, as ​ shown, when it is determined that the plurality of electronic components 11b arranged below the pressing surface 102 of the light-transmissive pressing member 100 are not arranged symmetrically left and right with respect to the center line Cn+2, pressing and laser irradiation will not be directly performed. This is because, in this state, if the light-transmissive pressing member 100 is pressed, the plurality of electronic components 11b will be arranged asymmetrically with respect to the center line Cn+2 of the pressing surface 102 of the light-transmissive pressing member 100. Therefore, when pressing, problems such as poor welding may occur due to the pressure being biased to one side.

[0310] Therefore, as ​ shown, in order to prevent the above problems, the present invention uses a control unit (not shown) to horizontally move the above light-transmissive pressing member 100 along a new center line Cn+2', and calibrates the horizontal position of the light-transmissive pressing member 100 through the center line Cn+2' calibrated thereby. Therefore, as the horizontal position is calibrated, a plurality of electronic components 11b arranged below the light-transmissive pressing member 100 will be symmetrically arranged left and right with respect to the calibrated center line Cn+2'. In this state, as ​ shown, the light-transmissive pressing member 100 moves downward to press the plurality of electronic components 11b and irradiate a laser beam.

[0311] On the other hand, referring to ​ , although the above light-transmissive pressing member 100 moves along the calibrated center line Cn+2' and performs pressing, in this case, the first laser module 310 and the second laser module 320 do not calibrate the horizontal position with respect to the calibrated center line Cn+2', and will irradiate the laser beam based on the center line Cn+2 before calibration.

[0312] As described above, the reason why the laser modules 310 and 320 do not calibrate the horizontal position based on the light-transmissive pressing member 100 is that when the laser beam is irradiated based on the calibrated center line Cn+2', there is a risk that a plurality of electronic components 11b that have completed the above welding will be irradiated with the laser beam again. Moreover, if the above laser beam irradiates the solder 11c that has completed the reflow soldering process again, the above solder 11c may melt again, and thus, there is a problem of causing poor soldering. Therefore, when pressing and laser irradiating the asymmetrically arranged electronic components 11b, the present invention does not need to perform the position calibration of the first laser module 310 or the second laser module 320. After calibrating the position by only horizontally moving the light-transmissive pressing member 100 along the calibrated center line Cn+2', during the pressing and laser irradiation processes, the occurrence of various soldering defect factors as described above can be minimized.

[0313] ​ FIG. is a state diagram showing the working relationship according to the process of the laser reflow soldering method of the present invention. Hereinafter, various soldering modes that can be combined according to each process will be described in detail according to the embodiments.

[0314] First, referring to ​ , as the most basic soldering mode of the present invention, the first soldering mode may include the following steps: moving the pressing surface 102 of the above light-transmissive pressing member 100 downward to contact the soldering object 11 in a state where no pressure is applied; irradiating the soldering object 11 with a laser beam through the above light-transmissive pressing member 100; and releasing the irradiation of the laser beam and moving the light-transmissive pressing member 100 upward.

[0315] In this case, as described above ​ shown, in the step of bringing the above-mentioned light-transmissive pressing member 100 into contact with the welding object 11 in a non-pressurized state, as the motor 760 is driven, the pressing bracket 720 connected to the motor 760 and the ball screw 750 moves downward. Since the pressing bracket 720 is in a state where the bracket unit 500 and the light-transmissive pressing member 100 are installed, as a result, the light-transmissive pressing member 100 moves downward by the drive of the motor.

[0316] Referring to ​ , when the above-mentioned light-transmissive pressing member 100 moves downward and comes into contact with the electronic component 11b of the welding object 11, as the motor 760 that provides the driving force for moving the above-mentioned light-transmissive pressing member 100 downward stops driving, the above-mentioned light-transmissive pressing member 100 will be in a state of contacting the upper surface of the electronic component 11b in a non-pressurized state. At this time, since the above-mentioned motor is in a locked state, the light-transmissive pressing member 100 will also be in a height-fixed state where it cannot move vertically.

[0317] Next, referring to ​ , in the state where the above-mentioned light-transmissive pressing member 100 is in contact with the upper surface of the electronic component 11b, the multi-laser modules provided above the above-mentioned light-transmissive pressing member 100, that is, the first laser module 310 and the second laser module 320 irradiate laser beams on the welding object 11 through the light-transmissive pressing member 100.

[0318] In this case, since the above-mentioned laser beams are overlapped and irradiated, a homogenized laser beam can be transmitted to the above-mentioned plurality of electronic components 11b and solder 11c. As described above, since the above-mentioned welding object 11 is already at the preheating temperature, for example, the welding object 11 is in a state of being preheated to less than 200 °C, even if the laser beam does not heat the welding object 11 to the melting temperature of the solder 11c, for example, quickly heated to 250 °C, it can be stably heated from the preheating temperature to the melting temperature of the solder 11c. Thus, if laser reflow soldering is started, the upper surface of the above-mentioned solder 11c is in contact with the pressing surface 102 of the light-transmissive pressing member 100. Therefore, when the solder 11c melts, it will prevent the electronic component 11b located above the above-mentioned solder 11c from bending upward or floating.

[0319] Subsequently, if the soldering is completed, the irradiation of the above-mentioned laser beam is terminated and the light-transmissive pressing member 100 is moved upward to complete the first soldering mode.

[0320] On the other hand, other soldering modes in which a plurality of steps are additionally added to the above-mentioned first soldering mode will be described in detail below according to the embodiments.

[0321] Similar to the first welding mode described above, in the second welding mode, after the light-transmissive pressing member 100 comes into contact with the electronic component 11b of the welding object 11, the pressing cylinder 730 disposed above the light-transmissive pressing member 100 presses the light-transmissive pressing member 100 with a specified pressure.

[0322] Subsequently, as described above, in a state where the light-transmissive pressing member 100 presses the welding object 11, if a laser beam is irradiated, as the solder 11c of the welding object 11 is melted, the pressure will be released. In this case, it can be predicted that the height of the electronic component 11b will decrease by a specified height hc due to the compression of the solder 11c (refer to ​ ). In this state, if the lock of the motor 760 is released, the light-transmissive pressing member 100 gradually moves downward due to its weight. Eventually, the light-transmissive pressing member 100 moves downward according to the degree of pressure applied by the pressing cylinder 730 described above, thereby maintaining the pressure.

[0323] Therefore, the difference between the second welding mode and the first welding mode is that before irradiating the laser beam, as pressure is applied, when the solder 11c is melted due to the application of the laser beam, the light-transmissive pressing member 100 also moves downward together and maintains the pressure. Thus, when the solder 11c is melted, since a specified pressure applied to the solder 11c is maintained, a dense welding can be obtained by reducing the floating of the electronic component 11b or the poor contact of the solder 11c, etc.

[0324] Moreover, the third welding mode is the same as the first welding mode. Similar to the first welding mode described above, after the light-transmissive pressing member 100 comes into contact with the electronic component 11b of the welding object 11, a laser beam is irradiated in a state where no pressure is applied.

[0325] After irradiating the laser beam, as the pressing cylinder 730 is driven, a specified pressure is applied to the light-transmissive pressing member 100 and the welding object 11. In this case, the motor 760 is locked, and the light-transmissive pressing member 100 is fixed so that it cannot move vertically, and is in a state where only the pressing cylinder 730 applies pressure. Different from the first welding mode, in the third welding mode, pressure is applied after irradiating the laser beam.

[0326] Until the step of irradiating the laser beam, although the fourth welding mode is the same as the third welding mode described above, there is the following difference, that is, after irradiating the laser beam, instead of applying pressure, the height of the light-transmissive pressing member 100 is changed.

[0327] Therefore, when the laser beam starts to be irradiated, as the locking of the motor is released, the above-mentioned light-transmissive pressing member 100 will gradually move downward. As a result, it is possible to prevent poor soldering caused by the sudden pressure on the solder 11c melted by the laser beam by slowly pressing the electronic component 11b and the melted solder 11c.

[0328] As described above, in terms of preventing poor soldering by adjusting the pressure change caused by the melting of the solder, the above-mentioned soldering mode can have various embodiments.

[0329] Therefore, the present invention is not limited to the embodiments described above. In the case of changing some steps or adding additional steps by changing the detailed structure, quantity, and configuration structure of the device, the same effect can also be achieved. It should be understood that those of ordinary skill in the technical field to which the present invention pertains can add, delete, and modify various structures within the scope of the technical idea of the present invention.

[0330] Description of Reference Numerals

[0331] 11: Object to be Soldered 11a: Substrate

[0332] 11b: Electronic Component 12: Laser Overlapping Irradiation Area

[0333] 100: Light-Transmissive Pressing Member 101: Substrate

[0334] 101a: Step Portion 102: Pressing Surface

[0335] 102a: Lattice Groove 103: Laser Blocking Layer

[0336] 104: Silicon Damping Layer 200: Protective Film

[0337] 210: Protective Film Transfer Unit 310: First Laser Module

[0338] 318, 328: Beam Analyzer 320: Second Laser Module

[0339] 500: Bracket Unit 510: Lower Plate

[0340] 520: Mask Plate 600: Probe Unit

[0341] 610: Probe 620: Probe Transfer Unit

[0342] 630: Probe Bracket 700: Stamping Unit

[0343] 710: Pressure Balancer 720: Stamping Bracket

[0344] 730: Pressing Cylinder 740: Pressure Sensor

[0345] 750: Ball screw 760: Motor

[0346] 770: Guide component 780: Bearing joint

[0347] 790: Stopping part 800: Ionizer

[0348] 810: Infrared temperature sensor 811: Infrared irradiation point

[0349] 910: Input conveyor 920, 960: Horizontal transfer unit

[0350] 930, 970: Adsorption pad 934: Vision unit

[0351] 940: Vacuum suction cup 942: Heating block

[0352] 943: Porous adsorption plate 950: Output conveyor

[0353] 980: Adsorption plate lifting unit

Claims

1. A laser reflow soldering device, which adopts a pressing method of irradiating a laser while pressing a plurality of electronic components arranged on a substrate with a light-transmitting pressing member, and is characterized in that it includes: A laser pressing head module, which presses the soldering object through the above-mentioned light-transmitting pressing member and irradiates a homogenized square laser beam through the above-mentioned light-transmitting pressing member to simultaneously solder a plurality of electronic components to the above-mentioned substrate, and the above-mentioned soldering object is composed of a plurality of electronic components arranged on the above-mentioned substrate; A soldering object transfer module, which is used to transfer the above-mentioned soldering object so that the soldering object carried in from one side of the above-mentioned laser pressing head module undergoes reflow soldering treatment by the above-mentioned laser pressing head module and is transported out toward the other side, The above-mentioned laser pressing head module includes: A bracket unit, which is used to install the above-mentioned light-transmitting pressing member in a replaceable manner; and A probe unit, which is arranged above the above-mentioned bracket unit and is used to detect the flatness of the above-mentioned light-transmitting pressing member installed on the bracket unit; A stamping unit, which is axially combined with three positions around the edge of the above-mentioned bracket unit, and independently presses the above-mentioned three positions of the above-mentioned bracket unit with a preset pressure. When the above-mentioned axially combined positions are connected by a dotted line, a triangle is formed, The above-mentioned bracket unit is circular or polygonal and includes: A lower plate, which is formed with a square through hole in the central part for inserting, locking and placing the above-mentioned light-transmitting pressing member; A mask plate, which is formed with a through hole in the central part to allow the laser beam to pass through, so that the above-mentioned light-transmitting pressing member is combined with the upper part of the above-mentioned lower plate in a state of being placed on the above-mentioned lower plate. The through hole is a square with an area larger than or the same as the pressing surface of the light-transmitting pressing member, The above-mentioned light-transmitting pressing member includes: A base material, which is integrally in the shape of a square plate; and A pressing surface, which protrudes from the bottom surface of the above-mentioned base material, and the area of the above-mentioned pressing surface corresponds to the processing area of the above-mentioned soldering object, One or more stepped portions are formed between the above-mentioned base material and the pressing surface of the above-mentioned light-transmitting pressing member in a manner that the area of the above-mentioned pressing surface is smaller than the area of the above-mentioned base material and recesses inward, A laser blocking layer is formed on the side surface of the above-mentioned base material of the above-mentioned light-transmitting pressing member and the bottom surface and side surface of the above-mentioned stepped portion, The above-mentioned stamping unit includes: A stamping bracket; A pressing cylinder, which is installed at the upper end of the above-mentioned stamping bracket and presses the above-mentioned bracket unit downward with a preset pressure, The virtual triangle formed by connecting the above-mentioned three positions of the above-mentioned bracket unit is an equilateral triangle, and the centroid of the above-mentioned virtual triangle is the same as the centroid of the above-mentioned light-transmitting pressing member.

2. The laser reflow soldering device according to claim 1, wherein The left and right corner portions of the bottom surface of the above-mentioned lower plate are in an arc shape.

3. The laser reflow soldering device according to claim 1, wherein The above-mentioned probe unit includes: A probe, which measures the flatness by piercing one or more positions on the upper surface of the light-transmitting pressing member; A moving unit, which is used to horizontally or vertically move the above-mentioned probe; and A probe bracket, which is used to fix the above-mentioned probe and the moving unit.

4. The laser reflow soldering device according to claim 3, characterized in that, The above-mentioned probe pierces through four or more positions including the respective corner positions of the square on the upper surface of the light-transmitting pressing member.

5. The laser reflow soldering device according to claim 1, wherein It further includes a protective film formed on the lower part of the above-mentioned light-transmissive pressing member to prevent the gas generated during laser welding from adhering to the bottom surface of the light-transmissive pressing member.

6. The laser reflow soldering device according to claim 5, wherein, The above-mentioned protective film is made of polytetrafluoroethylene resin or soluble polytetrafluoroethylene resin.

7. The laser reflow soldering device according to claim 6, characterized in that, The above-mentioned protective film is supplied by a roll-to-roll type protective film transfer unit that transfers the protective film wound in a roll form to one side.

8. The laser reflow soldering device according to claim 1, characterized in that, The above-mentioned laser barrier layer is one of a nickel-chromium-iron alloy coating, a scattering treatment layer, or a high-reflection coating, or a composite layer composed of two or more of them.

9. The laser reflow soldering device according to claim 1, wherein The above-mentioned stamping unit further includes: A bearing joint, one end of which is combined with the cylinder rod of the above-mentioned pressing cylinder, and the other end is rotatably combined with one of the above-mentioned three positions of the above-mentioned bracket unit respectively.

10. The laser reflow soldering device according to claim 9, wherein, Joint fastening parts are respectively provided at the above-mentioned three positions of the above-mentioned bracket unit, and the above-mentioned joint fastening parts are rotatably combined with the above-mentioned bearing joints respectively.

11. The laser reflow soldering device according to claim 10, wherein, A stop part is further provided at the lower end of the above-mentioned stamping bracket, and one end of the joint fastening part is hung on the above-mentioned stop part.

12. The laser reflow soldering device according to claim 1, wherein, The above-mentioned pressing cylinder is a precision air pressure cylinder, which can achieve fine setting and adjustment of pressure in kgf units.

13. The laser reflow soldering device according to claim 12, wherein, A pressure sensor for measuring the pressure during pressing and continuously performing feedback is further provided on the above-mentioned pressing cylinder.

14. The laser reflow soldering device according to claim 1, wherein An ionizer unit for keeping the upper surface of the light-transmissive pressing member clean from the influence of dust adsorption caused by static electricity on dust is further provided above the above-mentioned bracket unit.

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