Laser reflow soldering apparatus with vacuum chamber pressurization method

Abstract

The laser reflow soldering apparatus of the present invention, characterized by a pressurized vacuum chamber, comprises: a vacuum chamber formed of a hexahedral sealed space, with an inlet and an outlet formed on one and the other side of the hexahedron respectively, for selectively opening and closing to introduce or remove a substrate into or from the sealed space; a laser beam irradiation hole formed in the upper part of the sealed space; a support portion disposed above the laser beam irradiation hole of the vacuum chamber, wherein a light-transmitting pressurizing component is inserted and mounted in a replaceable manner, and the support portion maintains an airtight connection with the laser beam irradiation hole of the vacuum chamber without disrupting the vacuum atmosphere inside the vacuum chamber; and a pressurizing portion that, by vertically raising and lowering the support portion on which the light-transmitting pressurizing component is mounted, selectively presses and pressurizes the substrate located inside the vacuum chamber by the light-transmitting pressurizing component.

Description

Technical Field

[0001] This invention relates to laser reflow soldering apparatus, and more specifically, to a laser reflow soldering apparatus having a vacuum chamber pressurization method, wherein the invention performs a laser reflow soldering process based on pressurization of a light-transmitting pressurizing component and laser beam irradiation inside a vacuum chamber. This allows for batch processing by simultaneously pressurizing and laser reflow soldering multiple electronic components, effectively preventing voids caused by fume during the soldering process, thereby significantly improving the defect rate of the laser reflow soldering process. Background Technology

[0002] In industrial laser processing, applications requiring micrometer (μm) precision are known as microlaser processing, widely used in the semiconductor, display, printed circuit board (PCB), and smartphone industries. Memory chips used in all electronic devices have been developed to minimize circuit spacing in order to achieve high integration, performance, and ultra-high-speed communication. Currently, it is difficult to achieve the required technical level simply by reducing circuit linewidth and linewidth spacing, thus requiring the vertical stacking of multiple memory chips. TSMC has developed stacking technology up to 128 layers, while Samsung Electronics and SK Hynix have applied stacking technology down to 72 layers in mass production.

[0003] Furthermore, we are currently actively developing a technology that integrates memory chips, microprocessor chips, graphics processing chips, wireless processing chips, and sensor processing chips into a single package. This highly advanced technology is already being applied in practice.

[0004] However, in the aforementioned technology development process, more electrons are needed to participate in signal processing inside ultra-high-speed / ultra-high-capacity semiconductor chips. Therefore, with the increase in power consumption, the problem of cooling the generated heat becomes a focus. Furthermore, to achieve ultra-high-speed and ultra-high-frequency signal processing for more signals, technologies for transmitting large amounts of electrical signals at ultra-high speeds have been proposed. Moreover, since it is no longer possible to handle the external signal interface lines of semiconductor chips using one-dimensional leads due to the need to increase signal lines, a two-dimensional ball grid array (BGA) method (called Fan-In BGA or Fan-in Wafer-Level-Package (FIWLP)) is actually adopted. Alternatively, a two-dimensional micro-ball grid array layer (called Fan-Out BGA or Fan-Out Wafer-Level-Package (FOWLP)) is configured below the ultra-fine ball grid array layer on the chip, separated by a signal layout redistribution layer.

[0005] Recently, in the case of semiconductor chips, products with epoxy-mold compound (EMC) layers less than 200 μm thick are emerging. As mentioned above, mass reflow (MR) processes using existing surface mount technology (SMT) standard procedures, such as thermal reflow ovens, are used to attach ultra-thin semiconductor chips with thicknesses of only a few hundred micrometers to ultra-thin printed circuit boards. During this process, the semiconductor chips are exposed to air temperatures of 100–300 degrees Celsius for hundreds of seconds. Therefore, due to differences in the coefficient of thermal expansion (CTE), various forms of solder contact defects may occur, including chip-boundary warpage, PCB-boundary warpage, and random-bonding failure by thermal shock.

[0006] Therefore, the structure of the recently observed laser reflow soldering equipment is used to perform soldering by pressing the object to be soldered (semiconductor chip or integrated circuit (IC)) with the laser head module for several seconds and irradiating it with a laser. The laser is irradiated with a surface light source shape corresponding to the size of the semiconductor chip or integrated circuit.

[0007] For this type of pressurized laser head module, referring to Korean Patent No. 0662820 (hereinafter referred to as "Prior Document 1"), a structure of a flip chip pressurizing module is disclosed, which irradiates the rear surface of the flip chip with a laser to heat the flip chip and press the flip chip onto the carrier chuck substrate.

[0008] However, the laser head module of the existing pressure method disclosed in the aforementioned existing document 1 is divided into a unit that adsorbs the chip and moves it to the welding position and a unit that heats the back of the chip by laser and presses the chip onto the carrier chuck substrate. Therefore, in the case of welding multiple semiconductor chips, such as semiconductor strips, it is necessary to repeatedly perform the work of pressing one semiconductor chip and irradiating it with laser a number of times corresponding to the number of semiconductor chips, which can only increase the operation time.

[0009] On the other hand, referring to Korean Patent Publication 2018-0137887 (hereinafter referred to as "Prior Document 2"), the laser pressure head structure mentioned in the patent generally describes a welding process in which the laser head moves horizontally and sequentially irradiates each flip chip while the pressure head is simultaneously pressurizing multiple flip chips, or a single laser head simultaneously irradiates multiple flip chips.

[0010] However, according to the existing laser pressure head structure in the aforementioned literature 2, using a single laser module to simultaneously irradiate multiple flip chips with a single laser beam at multiple angles makes it technically difficult to achieve a homogenized laser beam and to reflow solder multiple flip chips without defects.

[0011] Therefore, based on the previous sequential pressure application and reflow soldering of a single flip chip, the overall operation time can only increase. Even if a single laser beam is applied to multiple flip chips arranged horizontally on various substrates to process multiple chips at the same time, it is actually difficult to uniformly transfer sufficient heat energy to each flip chip. Therefore, it is still difficult to improve the soldering defect rate.

[0012] Furthermore, recently, as electronic components soldered onto substrates have become increasingly miniaturized, the size of the solder joints has also become smaller. In the past, the laser reflow soldering process for such miniaturized soldering was still performed under normal pressure. Due to the fumes generated when the solder melts, a large number of voids were frequently produced during the soldering process.

[0013] Therefore, voids that occur during the micro-welding process can cause fatal structural or electrical defects in the weld. Moreover, the overall reliability of micro-patterns in reflow soldering is very fragile. Summary of the Invention

[0014] To address these issues, the present invention provides a laser reflow soldering apparatus with a vacuum chamber pressurization method. Specifically, the present invention performs pressurization based on a light-transmitting pressurizing component and laser reflow soldering based on laser beam irradiation inside the vacuum chamber. This allows for batch processing by simultaneously pressurizing and laser reflow soldering multiple electronic components, effectively preventing voids caused by smoke during the soldering process, thereby significantly improving the defect rate of the laser reflow soldering process.

[0015] According to an embodiment of the present invention for achieving the above-mentioned objective, the present invention includes: a vacuum chamber formed of a hexahedral sealed space portion, with an inlet and an outlet formed on one side and the other side of the hexahedron respectively, for selectively opening and closing to introduce or withdraw a substrate into or from the sealed space portion, and a laser beam irradiation hole formed in the upper part of the sealed space portion; a support portion disposed above the laser beam irradiation hole of the vacuum chamber, on which a light-transmitting pressure member is inserted and installed in a replaceable manner, maintaining an airtight state with the laser beam irradiation hole of the vacuum chamber without disrupting the vacuum atmosphere inside the vacuum chamber; and a pressure member that, by moving the support portion on which the light-transmitting pressure member is installed vertically up and down, selectively presses and presses the substrate located inside the vacuum chamber by the light-transmitting pressure member, thereby pressing and pressuring multiple electronic components arranged on the substrate by the light-transmitting pressure member under the vacuum atmosphere inside the vacuum chamber, and simultaneously irradiating the vacuum chamber with a laser beam by the light-transmitting pressure member to solder the electronic components to the substrate.

[0016] Furthermore, according to one embodiment, an O-ring of elastic material with a specified thickness is provided at the contact portion between the laser beam irradiation hole and the support portion in the vacuum chamber. The laser beam irradiation hole and the support portion maintain contact with the O-ring. Through the pressure part, the support portion and the light-transmitting pressure member placed on the support portion move up and down in the vertical direction.

[0017] Furthermore, according to one embodiment, an inlet for introducing a substrate is formed on one side of the vacuum chamber, and an outlet for leading out a substrate is formed on the opposite side to the inlet. Switches are provided at the inlet and outlet respectively, and the internal space of the vacuum chamber is selectively opened and closed by the switches.

[0018] Furthermore, according to one embodiment, a carrier chuck is provided inside the vacuum chamber. After the substrate introduced from the inlet is moved to the area directly below the laser irradiation hole and laser reflow soldering is performed, the substrate that has undergone the laser reflow soldering process is moved to the outlet and led out of the vacuum chamber.

[0019] Furthermore, according to one embodiment, two or more laser modules are disposed above the aforementioned vacuum chamber, and laser beams irradiated from the aforementioned laser modules are superimposed on multiple electronic components arranged on the substrate through a light-transmitting pressurizing component.

[0020] Furthermore, according to one embodiment, when viewed from a plane, the aforementioned support portion forms a laser beam irradiation hole at its center, and the outer perimeter of the support portion forms a circular or bilaterally symmetrical regular polygon shape. With the center point of the aforementioned support portion as a reference, arm portions are joined at the edges of the outer perimeter that are equally divided into three parts, and the aforementioned arm portions are respectively connected to the pressure portion.

[0021] Furthermore, according to one embodiment, a roll-to-roll protective film transfer part is provided on the outside of the inlet and outlet of the vacuum chamber, respectively, in order to prevent the protective film, which is rolled up in a roll shape, from adhering to the bottom surface when the smoke generated during laser welding is performed, and to move it to one side.

[0022] Furthermore, according to one embodiment, the switch is located at the lower part of the inlet or outlet and is in a waiting state. When the inlet or outlet is closed, it slides upward and blocks the inlet or outlet with a protective film inserted to airtightly seal the interior of the vacuum chamber.

[0023] Furthermore, according to one embodiment, after the switch is closed, a vacuum pump is driven to create a vacuum atmosphere inside the vacuum chamber.

[0024] The present invention, as described above, has the following effect: it can simultaneously pressurize multiple electronic components and simultaneously irradiate a homogenized laser beam, thereby significantly improving productivity through batch processing.

[0025] Furthermore, the present invention has the following effect: the mask and the light-transmitting pressure component can be replaced in a manner corresponding to the substrate size or the configuration shape of the electronic components, thereby significantly reducing the defect rate as a variety of substrates are uniformly reflow soldered.

[0026] Furthermore, the present invention has the following effects: by performing the laser reflow soldering process in a vacuum atmosphere inside the vacuum chamber, voids caused by smoke are effectively prevented during the soldering process. Moreover, the defect rate caused by voids is improved, and the reliability of the laser reflow soldering process is enhanced.

[0027] Furthermore, the present invention has the following effect: in the internal vacuum atmosphere, the oxygen concentration is low, thus preventing oxidation of the vacuum chamber and the metal components and materials disposed inside the vacuum chamber. Moreover, the defect rate is further improved by reducing the particles generated when the metal is oxidized. Attached Figure Description

[0028] Figure 1 An illustrative diagram is provided to briefly illustrate the structure of the laser reflow soldering apparatus of the present invention, which has a pressurized vacuum chamber.

[0029] Figure 2 for Figure 1 The frame structure diagram.

[0030] Figure 3 This is a schematic diagram of a single laser module according to an embodiment of the present invention.

[0031] Figure 4 This is a schematic diagram of a multi-laser module according to another embodiment of the present invention.

[0032] Figure 5 This is a structural diagram of a multi-laser module according to another embodiment of the present invention.

[0033] Figures 6 to 9 This is a structural diagram of a laser optical system applicable to multiple laser modules, according to another embodiment of the present invention.

[0034] Figure 10 This is a partial longitudinal sectional view illustrating the structure of a laser reflow soldering apparatus with a vacuum chamber pressurization method according to an embodiment of the present invention.

[0035] Figure 11 for Figure 10 Enlarged view of the main part of section "A".

[0036] Figure 12 for Figure 10 Top view of the main parts. Detailed Implementation

[0037] The terminology used in this specification is for illustrative purposes only and is not intended to limit the invention. Unless the context clearly indicates otherwise, the singular includes the plural. In this specification, terms such as “comprising,” “having,” or “possessing” are used to specify the presence of features, numbers, steps, actions, structural elements, components, or combinations thereof described in this specification, and do not preclude the presence or additional possibilities of one or more other features, numbers, steps, actions, structural elements, components, or combinations thereof.

[0038] Unless otherwise defined in this specification, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0039] Terms as defined in commonly used dictionaries have the same meaning as those in the context of the relevant technology and should not be interpreted as having an ideal or overly formal meaning unless explicitly defined in this specification.

[0040] The following is for reference Figure 1 and Figure 2 The reflow soldering apparatus of the present invention will be described in detail below.

[0041] Figure 1 For the purpose of briefly illustrating the structure of the laser reflow soldering apparatus with a pressurized vacuum chamber according to the present invention, Figure 2 for Figure 1 The frame structure diagram.

[0042] like Figure 1 and Figure 2 As shown, the laser reflow soldering apparatus of the present invention includes: at least one multi-laser module 310, 320, which irradiates a surface light source-shaped laser onto a welding object 11 supported and transported by a conveyor belt 111 disposed inside a vacuum chamber 800; a light-transmitting pressure member 100, which is separately disposed from the laser modules 310, 320 and transmits the surface light source-shaped laser; and a protective film 200, which protects the light-transmitting pressure member 100 from contamination.

[0043] First, multiple multi-laser modules 310 and 320 convert the laser generated by the laser oscillator and transmitted through optical fibers into a surface light source and irradiate the object to be welded 11.

[0044] The aforementioned multi-laser modules 310 and 320 may include: a beam shaper (see reference) Figure 5 This transforms a point-shaped laser into a surface light source; and includes an optical section (see reference). Figures 5 to 9 The lens modules are arranged at the lower part of the beam shaper and are installed at appropriate intervals inside the lens barrel to irradiate the irradiation area of ​​the welding object 11 with the surface light source emitted from the beam shaper.

[0045] Furthermore, the aforementioned multi-laser modules 310 and 320 can move up or down along the z-axis, or move left or right along the x-axis, or move along the y-axis in order to align with the welding object 11.

[0046] The laser reflow soldering apparatus of the present invention independently separates the light-transmitting pressure member 100 that applies pressure by pressing the workpiece 11 to be welded and the laser modules 310 and 320 that irradiate the workpiece 11 with a laser in the form of a surface light source. Thus, while the workpiece 11 is being pressed by the light-transmitting pressure member 100, the laser modules 310 and 320 are moved to multiple irradiation positions on the workpiece 11 and driven, thereby reducing the tact time for one workpiece 11 and increasing the speed of the overall welding operation for multiple workpieces 11.

[0047] In this case, the light-transmitting pressurizing member 100 is moved to the working position or waiting position by a light-transmitting pressurizing member transfer section (not shown) of a predetermined shape. For example, the light-transmitting pressurizing member transfer section can lower or raise the light-transmitting pressurizing member 100 or move it left or right before lowering or raising it.

[0048] Furthermore, although not shown, the laser reflow soldering apparatus of the present invention may also include a control unit (not shown) that controls the operation of the light-transmitting pressurized component transfer unit (not shown) by means of data input from a pressure detection sensor (not shown) and a height sensor (not shown).

[0049] The aforementioned pressure detection sensor and height sensor can be installed on the conveyor belt 111 supporting the light-transmitting pressure component 100, the light-transmitting pressure component transfer section, and the welding object.

[0050] For example, the control unit receives data from the pressure detection sensor and controls the light-transmitting pressurized component transfer unit in a manner that makes the pressure reach the target value, and receives data from the height sensor and controls the light-transmitting pressurized component transfer unit in a manner that makes the height reach the target value.

[0051] Furthermore, the support (not shown) is provided in a manner that allows the light-transmitting pressurized component transfer part (not shown) to move.

[0052] As an example, the aforementioned support can be embodied as a pair of gantry frames extending side by side with the conveyor belt 111, including a structure that supports the light-transmitting pressurized component transfer section in a manner that allows it to move toward the x-axis, y-axis, or z-axis.

[0053] The laser reflow soldering apparatus of the present invention may include one or more pressure-applying units (see reference 100) that apply pressure to the light-transmitting pressure-applying member 100. Figure 10 and Figure 12 The light-transmitting pressurizing member 100 includes at least one pressure sensor (not shown) for detecting the pressure applied to it and one or more height sensors (not shown) for detecting the height of it.

[0054] In this case, as an example, the pressure sensor described above can be embodied as at least one load cell, and the height sensor can be embodied as a linear encoder.

[0055] By adjusting the pressure applied to the object being welded using the aforementioned pressure sensor, in the case of a large area, multiple actuators and multiple pressure sensors can be used to ensure that the same pressure is transmitted to the object being welded.

[0056] Furthermore, it can confirm the height position value of the welding object at the moment of welding through one or more height sensors, or provide technical data that allows for querying more accurate welding height values, and perform functions that can control the height accurately when performing processes that require maintaining a specified height at intervals.

[0057] Furthermore, the light-transmitting pressure component 100 can be formed of a base material that allows laser light output from the laser modules 310 and 320 to be transmitted. The base material of the light-transmitting pressure component 100 is formed of a beam-projecting material.

[0058] For example, the base material of the translucent pressurized component 100 may be formed from one of quartz, sapphire, fused silica glass, or diamond.

[0059] However, the physical properties of a translucent pressure component made of quartz are different from those of a translucent pressure component made of sapphire.

[0060] For example, when irradiated with a 980nm laser, the transmittance of a translucent pressure component made of quartz is 85%–99%, and the temperature measured in the workpiece being welded is 100°C. Conversely, the transmittance of a translucent pressure component made of sapphire is 80%–90%, and the temperature measured in the workpiece being welded is 60°C.

[0061] In other words, quartz exhibits superior performance compared to sapphire in terms of light transmittance and heat loss required for welding.

[0062] However, the inventors of this application, after developing a laser reflow soldering apparatus and repeatedly testing the translucent pressure component 100, discovered that the translucent pressure component 100, made of quartz material, suffers from poor welding quality due to cracking or burning on the bottom surface during laser welding.

[0063] The fumes generated during laser welding adhere to the bottom surface of the transparent pressure component 100, and the heat source of the laser is concentrated on the part where the fumes adhere, thereby increasing thermal stress.

[0064] To prevent damage to the light-transmitting pressure component 100 made of quartz and to improve its durability, a thin film coating can be formed on the bottom surface of the light-transmitting pressure component made of quartz.

[0065] The thin film coating formed on the bottom surface of the light-transmitting pressure component 100 can be a dielectric coating, a SiC coating, or a metallic coating, which are common optical coatings.

[0066] like Figure 1 As shown, the laser reflow soldering apparatus of the present invention may further include: a protective film 200 to prevent fumes generated during laser welding to the lower part of the light-transmitting pressure member 100 from adhering to the bottom surface of the light-transmitting pressure member 100; and a protective film transfer part 210 for transferring the protective film 200.

[0067] According to one embodiment, the protective film transfer section 210 can be formed by unrolling the protective film 200 which is wound in a roll shape and moving it to one side in a roll-to-roll manner.

[0068] As an example, preferably, the protective film 200 is formed of a material with a maximum operating temperature of 300°C or higher, a continuous maximum operating temperature of 260°C or higher, and excellent heat resistance.

[0069] For example, the aforementioned protective film 200 may be formed from polytetrafluoroethylene resin (commonly referred to as Teflon resin) and perfluoroalkoxy resin.

[0070] Perfluoroalkoxy resin (PFA) is a product designed to improve the heat resistance of fluorinated ethylene propylene resin. Its highest continuous temperature has been recorded at 260°C, the same as that of polytetrafluoroethylene resin, making it a high-performance resin.

[0071] Figure 3 This is a schematic diagram of a single laser module according to an embodiment of the present invention. Figure 4 This is a schematic diagram of a multi-laser module according to another embodiment of the present invention.

[0072] Referring to the above Figure 3 According to one embodiment of the present invention, a single laser module 310 is provided, thereby irradiating a flexible printed circuit board substrate with a single laser beam. In this case, the laser beam irradiated by the first laser module 310 irradiates the substrate in a square beam shape that is deformed to homogenize the intensity of the laser beam.

[0073] On the other hand, referring to the above Figure 4 For example, in another embodiment of the present invention, the multi-laser module includes a first laser module 310 and a second laser module 320. At the position where the electronic component of the object to be welded 11 is attached, the first laser module and the second laser module irradiate each other in an overlapping state, thereby irradiating a homogenized overlapping laser beam.

[0074] Figure 4 The diagram shows that the first laser beam is square and the second laser beam is circular; both laser beams can be square. Furthermore, the first and second laser beams can irradiate simultaneously, or the second laser beam can irradiate sequentially after the welding object 11 is preheated based on the first laser beam.

[0075] Figure 5 This is a structural diagram of a multi-laser module according to another embodiment of the present invention.

[0076] Figure 5 In this process, each laser module 310, 320, ..., 330 includes a laser oscillator 311, 321, 331 with cooling devices 316, 326, 336, a beam shaper 312, 322, 332, an optical lens module 313, 323, 333, a drive device 314, 324, 334, a control device 315, 325, 335, and a power supply unit 317, 327, 337.

[0077] Hereinafter, unless otherwise required, to avoid repetition, the description will focus on the first laser module 310 among the various laser modules having the same structure.

[0078] The laser oscillator 311 generates a laser beam with a specified range of wavelengths and output power. As an example, the laser oscillator can be a laser diode (LD), a rare-earth-doped fiber laser, or a rare-earth-doped crystal laser with wavelengths of 750 nm to 1200 nm, 1400 nm to 1600 nm, 1800 nm to 2200 nm, or 2500 nm to 3200 nm. Alternatively, it may include a medium for emitting alexandrite laser light with a wavelength of 755 nm or Nd:YAG laser light with a wavelength of 1064 nm or 1320 nm.

[0079] The beam shaper 312 converts a point-shaped laser generated from a laser oscillator and transmitted through an optical fiber into an area beam shape with a flat top. The beam shaper 312 may include a square light pipe, a diffractive optical element (DOE), or a micro-lens array (MLA).

[0080] The optical lens module 313 adjusts the shape and size of the laser beam, which is converted into a surface light source in the beam shaper, to illuminate electronic components mounted on a printed circuit board or the area to be illuminated. The optical lens module combines multiple lenses to form an optical system. Figures 6 to 9 Please provide a detailed description of the specific structure of this optical system.

[0081] The driving device 314 moves the laser module relative to the irradiation surface by a distance and position. The control device 315 controls the driving device 314 to adjust the beam shape, beam area, beam sharpness, and beam irradiation angle when the laser beam reaches the irradiation surface. In addition to the driving device 314, the control device 315 can also control the operation of various parts of the laser module 310.

[0082] On the other hand, the laser output adjustment unit 370 can control the amount of electricity supplied to each laser module from the power supply units 317, 327, and 337 corresponding to each laser module 310, 320, and 330 according to a program received through the user interface or a preset program. The laser output adjustment unit 370 receives reflow soldering status information for each component, each area, or the entire irradiated surface from one or more camera modules 350 and controls each power supply unit 317, 327, and 337 based on this information.

[0083] In contrast, control information from the laser output adjustment unit 370 is transmitted to control devices 315, 325, and 335 of each laser module 310, 320, and 330. Each control device 315, 325, and 335 can also provide feedback signals for controlling its corresponding power supply unit 317. Furthermore, with... Figure 6 Alternatively, power can be distributed to each laser module through a single power supply unit. In this case, the laser output adjustment unit 370 controls the power supply unit.

[0084] In the case of laser overlap mode, the laser output adjustment unit 370 controls each laser module and power supply unit 317, 327, 337 so that the laser beams from each laser module 310, 320, 330 have the required beam shape, beam area, beam clarity and beam illumination angle.

[0085] In addition to the case where the first laser module 310 preheats the area surrounding the welding object and the second laser module 320 adds heat to a narrower reflow soldering area, the laser overlay mode is also suitable for controlling each laser module in a way that appropriately distributes the preheating or additional heating functions to the first laser module 310, the second laser module 320, and the third laser module 330 to achieve the required temperature profile.

[0086] On the other hand, when a single laser source is allocated to each laser module, the laser output adjustment unit 370 can simultaneously adjust the output and phase of each allocated laser beam. In this case, the beam flatness can be significantly improved by controlling the phase in a way that induces anti-interference between the laser beams, thereby further increasing energy efficiency.

[0087] On the other hand, when processing modes are implemented simultaneously at multiple locations, the laser output adjustment unit 370 controls one or more of the following parameters of each laser beam: beam shape, beam area, beam sharpness, beam illumination angle, and beam wavelength, in a manner that is partially or completely different from that of each laser module. In this case, when a single laser source is allocated to input to each laser module, the laser output adjustment unit 370 can have the function of simultaneously adjusting the output and phase of each allocated laser beam.

[0088] This function allows for the bonding or removal of electronic components from the substrate within the irradiated surface by adjusting the size and output of the laser beam. In particular, when removing damaged electronic components from the substrate, by minimizing the area of ​​the laser beam to the corresponding electronic component region, the application of heat based on the laser beam to adjacent or normal electronic components present on the substrate can be minimized, thereby removing only the damaged electronic components that are to be removed.

[0089] On the other hand, when each of the multiple laser modules emits laser beams with different wavelengths, the laser modules can be composed of individual laser modules having wavelengths that are well absorbed by each of the multiple material layers (e.g., epoxy molding compound layer, silicone layer, solder layer) included in the electronic component. Thus, the laser welding apparatus of the present invention can perform optimized attachment or bonding or detaching processes by varying the temperature of the electronic component and the intermediate bonding material, such as solder, which serves as a connecting device between electrodes of the printed circuit board or electronic component.

[0090] Specifically, all the energy of each laser beam is absorbed through the epoxy molding compound layer and silicone layer of the electronic component and by the solder layer, or the laser beam does not pass through the epoxy molding compound layer, but heats the surface of the electronic component to transfer the heat to the solder part under the electronic component.

[0091] On the other hand, using the above functions, after preheating a specified area of ​​the electronic component area to be reflow soldered and the surrounding substrate to a specified preheating temperature by at least one first laser beam, the temperature of the electronic component area to be reflow soldered is selectively heated to a reflow soldering temperature that triggers the melting of the solder by at least one second laser beam.

[0092] Figures 6 to 9 This is a structural diagram of a laser optical system that can be used with a single laser module or multiple laser modules in the laser pressure head module of this invention.

[0093] Figure 6For the simplest optical system applicable to the present invention, if the laser beam emitted from the beam transmission fiber 410 is focused and incident on the beam shaper 430 through the convex lens 420, then in the beam shaper 430, the point-shaped laser beam is converted into a flat-top surface light source A1. The positive direction laser beam A1 output from the beam shaper 430 is magnified to the required size by the concave lens 440 and illuminates the imaging surface S as a magnified surface light source A2.

[0094] Figure 7 This is a structural diagram of a laser optical system according to another embodiment of the present invention.

[0095] The surface light source B1 from the beam shaper 430 is magnified to a predetermined size by the concave lens 440 and referred to as the surface light source B2 illuminating the first imaging surface S1. When the surface light source B2 is further magnified for use, the boundaries of the edges of the surface light source B2 become less defined with further magnification. Therefore, in order to obtain illumination light with the edges of the illuminating surface clearly defined on the second imaging surface S2, a mask 450 is set on the first imaging surface S1 to trim the edges.

[0096] The surface light source of the mask 450 passes through the zoom lens module 460, which consists of one or more convex and concave lenses, and is reduced (or magnified) to the required size to form a quadrilateral illumination light B3 on the second imaging surface S2 where the electronic components are arranged.

[0097] Figure 8 This is a structural diagram of a laser optical system according to another embodiment of the present invention.

[0098] After the positive-direction surface light source C1 from the beam shaper 430 is magnified to a predetermined size by the concave lens 440, it passes through at least one pair of cylindrical lenses 470, for example, magnified (or reduced) in the x-axis direction C2, and then passes through at least one pair of cylindrical lenses 480, for example, reduced (or magnified) in the y-axis direction, and is converted into a rectangular surface light source C3.

[0099] Among them, the cylindrical lens is a shape that cuts a cylinder along its length. It serves to expand or shrink the laser beam according to the shape in which each lens is arranged in the up and down direction. On the surface where the cylindrical lens is arranged, the laser beam is irradiated in the x-axis or y-axis direction according to the shape in which the lens is arranged in the x-axis or y-axis direction.

[0100] Next, the surface light source C3 passes through a zoom lens module 460 composed of one or more convex and concave lenses and is magnified (or reduced) to the required size, forming a rectangular illumination light C4 on the second imaging surface S2 where electronic components are configured.

[0101] Figure 9 This is a structural diagram of a laser optical system according to another embodiment of the present invention.

[0102] Figure 9 The optical system has been added in Figure 8 The optical system uses masks to trim the edges and corners of the laser beam, and... Figure 8 Compared to the previous case, the final surface light source D5 can achieve more distinct edges and corners.

[0103] Figure 10 This is a partial longitudinal sectional view illustrating the structure of a laser reflow soldering apparatus with a vacuum chamber pressurization method according to an embodiment of the present invention. Figure 11 for Figure 10 Enlarged view of the main part of section "A". Figure 12 for Figure 10 Top view of the main parts.

[0104] The following is for reference Figures 10 to 12 The structure of the laser reflow soldering apparatus with a vacuum chamber pressurization method according to the present invention is described in more detail below.

[0105] First, refer to Figure 10 The laser reflow soldering apparatus of the present invention includes a vacuum chamber 800 formed by a hexahedral sealed space portion.

[0106] An inlet 801 and an outlet 802 are formed on one side and the other side of the vacuum chamber 800, respectively, for selectively opening and closing to introduce or withdraw the substrate 11, which is the object to be welded, into or from the sealed space of the vacuum chamber. A laser beam irradiation hole 803 is formed at the center of the upper surface of the vacuum chamber 800.

[0107] Furthermore, a support portion 500 is provided above the laser beam irradiation hole 803 of the aforementioned vacuum chamber 800, and the light-transmitting pressure-applying component 100 is replaceably inserted into the support portion 500. In this case, the light-transmitting pressure-applying component 100 placed in the support portion is positioned at its bottom (pressure surface) in contact with the workpiece for applying pressure to the workpiece, and is located inside the vacuum chamber through the laser irradiation hole (see reference). Figure 10 ).

[0108] Thus, the laser beam irradiated from the laser module 300 located above the vacuum chamber 800 is irradiated into the interior of the vacuum chamber 800 through the light-transmitting pressure member 100 installed on the bracket 500 and the laser irradiation hole 803 of the vacuum chamber 800.

[0109] Furthermore, at least one pressure section 700 is provided at an appropriate position along the edge of the aforementioned support section 500.

[0110] As described above, the pressurizing part 700 is a structural element that provides the power to raise and lower the support part 500, on which the light-transmitting pressurizing member 100 is placed, in the vertical direction. As the edge portion of the support part 500 on which the light-transmitting pressurizing member 100 is placed is selectively pressed to lower it, the substrate 11 located inside the vacuum chamber 800 is pressed and pressure is applied by the light-transmitting pressurizing member 100.

[0111] That is, under the vacuum atmosphere inside the vacuum chamber 800, pressure is applied by pressing the light-transmitting pressure member 100 through the pressure member 700 arranged on the substrate 11. At the same time, the laser beams irradiated from the laser modules 310 and 320 are irradiated into the vacuum chamber 800 through the light-transmitting pressure member 100.

[0112] The light-transmitting pressure member 100 can pressurize the substrate in various ways. For example, it can be a self-weight pressure mode where the light-transmitting pressure member 100 initially contacts the electronic components on the substrate 11 and then applies pressure by its own weight, or a forced pressure mode where the pressure member 700 further descends and applies pressure during the process of the electronic components on the substrate being irradiated by a laser beam. In the actual laser reflow soldering process of the present invention, one or more of the above-mentioned pressure modes can be used in combination.

[0113] In particular, the aforementioned support portion 500 is raised and lowered vertically by the pressurizing portion 700 with the light-transmitting pressurizing component 100 placed at the center. In this case, the aforementioned support portion 500 maintains an airtight state with the laser beam irradiation hole 803 of the vacuum chamber 800 in a manner that does not disrupt the vacuum atmosphere inside the vacuum chamber 800.

[0114] Therefore, an O-ring of elastic material OR with a specified thickness or more is provided at the contact area between the laser beam irradiation hole 803 of the vacuum chamber 800 and the support portion. The area around the laser beam irradiation hole 803 of the vacuum chamber 800 and the support portion 500 are in contact with each other through the O-ring OR provided therebetween, thus maintaining a mutually airtight contact state.

[0115] Furthermore, an inlet 801 for introducing the substrate is formed on one side of the aforementioned vacuum chamber 800, and an outlet 802 is formed on the opposite side facing the aforementioned inlet 801.

[0116] Furthermore, switches 900 are respectively provided at the inlet 801 and outlet 802, so that the inlet 801 and outlet 802 of the vacuum chamber 800 can be selectively opened and closed by the switches 900.

[0117] According to one embodiment, the switch 900 is positioned below the inlet 801 and outlet 802, adjacent to them. When the inlet 801 or outlet 802 is closed, the switch 900 slides upward and airtightly seals the inlet 801 or outlet 802 with the protective film 200 inserted into it.

[0118] Furthermore, after the aforementioned switch 900 is closed, a vacuum pump (not shown) is driven to create a vacuum atmosphere inside the vacuum chamber 800.

[0119] Furthermore, a carrier chuck 110 and a conveyor belt 111 are provided inside the vacuum chamber 800. After the substrate 11 introduced through the inlet 801 is moved directly below the light-transmitting pressurizing member 100 and laser reflow soldering is performed, the substrate 11 that has undergone the laser reflow soldering process is moved to the outlet 802 to be led out of the vacuum chamber 800.

[0120] Furthermore, a laser module 300 is provided above the aforementioned vacuum chamber 800, and the laser beam irradiated from the laser module 300 is superimposed on multiple electronic components arranged on the substrate 11 through the light-transmitting pressurizing component 100.

[0121] As described above, the laser module 300 can be a single laser module or a multi-laser module combining two or more laser modules. As needed, as described above... Figure 1 , Figure 2 , Figure 4 and Figure 5 As shown, two laser modules can be used for overlapping laser beam illumination, namely, a first laser module 310 and a second laser module 320.

[0122] Furthermore, when viewed from a plane, the aforementioned support portion 500 forms a laser beam irradiation hole 803 at its center, and the outer perimeter of the support portion 500 forms a circular or a square with a left-right symmetrical structure. Based on the center point of the aforementioned support portion 500, pressure portions 700 are connected to the outer perimeter at positions that are equally divided into three parts.

[0123] More specifically, refer to Figure 12 According to one embodiment, the planar shape of the support portion 500 can be a regular hexagon, and the light-transmitting pressure member 100 is replaceably placed at the center of the support portion 500. Furthermore, arms 510 are connected to three positions at the edges that are trisected at 120 degrees from the center of the plane of the support portion 500, and pressure members 700 are provided at the ends of the arms 510 opposite to the support portion 500, thereby raising and lowering the three arms 510 respectively.

[0124] Furthermore, a protective film transfer part 210 is provided on the outside of the inlet 801 and outlet 802 of the vacuum chamber 800, respectively, which unfolds the protective film 200 into a roll shape and moves it to one side in a roll-to-roll manner.

[0125] The protective film 200 prevents the fumes generated during laser welding from directly adhering to the bottom surface of the light-transmitting pressure component 100.

[0126] Therefore, as the protective film 200 below the light-transmitting pressurized component 100 performs multiple laser reflow soldering processes, in the event of smoke contamination, the protective film 200 unfolded from the protective film transfer section 210 (unwinder) outside the inlet 801 passes through the space between the light-transmitting pressurized component 100 and the substrate 11 inside the vacuum chamber 800 through the inlet 801 and wraps around the protective film transfer section 210 (winder) outside the outlet 802, so that the new protective film 200 that is not contaminated by smoke is located below the light-transmitting pressurized component 100.

[0127] The working relationship of the laser reflow soldering apparatus of the present invention with the above-described structure will be explained below.

[0128] First, as the inlet 801 side switch 900 of the vacuum chamber 800 is opened, the substrate 11, which is the object to be welded, is introduced into the vacuum chamber 800 through the inlet 801 and then loaded onto the carrier chuck 110. The carrier chuck 110, with the substrate 11 loaded, moves the substrate directly below the light-transmitting pressure member 100 via the conveyor belt 111.

[0129] Next, after the switch 900 on the inlet 801 side is closed, although not shown, a vacuum pump (not shown) connected to one side of the vacuum chamber 800 is driven to discharge the air inside the vacuum chamber 800 to the outside of the vacuum chamber 800, thus creating a vacuum atmosphere inside the vacuum chamber 800.

[0130] Next, if the vacuum chamber 800 reaches the preset negative pressure, the laser reflow soldering process of the pressurization method of the present invention is carried out. First, as the pressurization part 700 lowers the support part 500, the light-transmitting pressurization component 100 placed in the support part 500 also lowers into the vacuum chamber 800.

[0131] In this case, when the aforementioned support portion 500 descends, it presses and compresses the O-ring OR disposed between the vacuum chamber 800 and the support portion 500. The O-ring OR is pressed by the support portion 500, compressing the degree of descent of the support portion 500 (see reference). Figure 11 ).

[0132] As a result, the O-ring OR is pressed and compressed by the distance g that the support portion 500 and the light-transmitting pressure member 100 descend, so that the electronic components on the substrate 11 of the object to be welded, which are transferred for laser reflow soldering processing in the vacuum chamber 800, come into contact with the light-transmitting pressure member 100 that descends together with the support portion 500 in the state of being placed in the support portion 500.

[0133] That is, refer to Figure 11 Before being compressed by the support section 500, the height h1 of the O-ring OR-1 is subtracted from the height h2 of the O-ring OR-2 after compression, causing the support section 500 to lower the gap g of the O-ring OR being compressed.

[0134] Next, as the light-transmitting pressure member 100 descends, it applies pressure to the electronic components disposed on the substrate 11 at a predetermined pressure. At the same time, the laser beam irradiated from the laser module 300 irradiates the electronic components on the substrate 11 through the light-transmitting pressure member 100 and the laser beam irradiation hole 803 of the vacuum chamber 800 and heats the solder (not shown).

[0135] Thus, the electronic components on the substrate 11, which are the objects to be welded, are pressurized by the light-transmitting pressure member 100. At the same time, as they are heated by the laser beam, the solder (not shown) disposed at the lower part of the electronic components melts, thereby welding the electronic components onto the substrate 11. This completes the laser reflow soldering process of the present invention.

[0136] Furthermore, as described above, when the overlapping laser beam irradiates the peripheral substrate portion other than the electronic components, the peripheral substrate portion may be damaged by the heat energy of the laser beam. Therefore, it is necessary to irradiate only the electronic components of the object to be welded 11.

[0137] Therefore, preferably, in order to accurately pressurize and laser reflow solder the electronic components of the object to be soldered 11, the area of ​​the laser irradiation hole 803 and the light-transmitting pressure component 100 needs to be designed taking into account the projection path of the laser beam and the overlapping area.

[0138] Furthermore, preferably, the present invention allows for the replacement of the light-transmitting pressure member 100 of the support portion 500 in a manner that can accommodate various substrate sizes 11.

[0139] Therefore, the support portion 500 and the light-transmitting pressure member 100 can be replaced depending on the size of the substrate 11 being processed or the shape and area of ​​the electronic components disposed on the substrate 11.

[0140] Furthermore, although not shown, after replacing the light-transmitting pressure component 100, the present invention uses a separate detection unit (not shown) to probe the upper surface of the light-transmitting pressure component 100 to measure the flatness of the replaced light-transmitting pressure component 100.

[0141] Therefore, in order to process substrates 11 of different sizes, after the operator replaces the light-transmitting pressure component 100 of different sizes, the flatness of the light-transmitting pressure component 100 can be measured using the above-mentioned detection unit (not shown). The flatness adjustment process of the light-transmitting pressure component 100 can be automated by setting the control unit.

[0142] Furthermore, the present invention is not limited to the embodiment described above. The same effect can be obtained by changing the detailed structure, quantity, or configuration of the device. Therefore, anyone skilled in the art can add, delete, and modify various structures within the scope of the technical concept of the present invention.

Claims

1. A laser reflow soldering apparatus with a pressurized vacuum chamber, characterized in that, include: A vacuum chamber is formed from a hexahedral sealed space. An inlet and an outlet are formed on one side and the other side of the hexahedron, respectively, to selectively open and close the chamber by introducing or removing a substrate into or from the sealed space. A laser beam irradiation hole is formed in the upper part of the sealed space. An inlet for introducing the substrate is formed on one side of the vacuum chamber, and an outlet for removing the substrate is formed on the opposite side of the inlet. Switches are provided at the inlet and outlet, and the internal space of the vacuum chamber is selectively opened and closed by the switches. A support unit, positioned above the laser beam irradiation aperture of the aforementioned vacuum chamber, is fitted with a light-transmitting pressurizing component that can be replaced, maintaining an airtight seal with the laser beam irradiation aperture of the vacuum chamber without disrupting the vacuum atmosphere inside the chamber; and The pressurizing unit, by vertically raising and lowering the support section on which the aforementioned light-transmitting pressurizing component is mounted, selectively presses and applies pressure to the substrate located inside the vacuum chamber via the light-transmitting pressurizing component. An O-ring of elastic material with a specified thickness is also provided at the contact point between the laser beam irradiation hole and the support portion in the aforementioned vacuum chamber. The aforementioned laser beam irradiation aperture and support portion maintain contact with the O-ring. Through the pressurizing portion, the support portion and the light-transmitting pressurizing component placed on the support portion move vertically upwards and downwards. As the aforementioned support unit descends, the O-ring is pressed and compressed by the support unit, so that the light-transmitting pressure component, which is placed in the state of the support unit and descends together with the support unit, moves up and down within the gap between the height h1 of the O-ring before compression and the height h2 of the O-ring after compression. The light-transmitting pressure-applying component, placed on the aforementioned support, is positioned with its bottom in contact with the object being welded. Through the laser beam irradiation hole, it is located inside the vacuum chamber. Using this pressure-applying component, multiple electronic components arranged on the substrate are pressed and pressurized under vacuum conditions within the vacuum chamber. The bottom surface in contact with the object being welded is the pressure-applying surface. A laser beam, emanating from a laser module positioned above the vacuum chamber, passes through a light-transmitting pressurizing component mounted on the aforementioned support and a laser beam irradiation aperture within the vacuum chamber. This beam then irradiates multiple electronic components arranged on a substrate inside the vacuum chamber. The solder is heated and melted, causing the electronic components to be soldered onto the substrate and subjected to laser reflow soldering. The aforementioned laser reflow soldering process includes: a self-weight pressurization mode in which the transparent pressurizing component initially contacts the electronic component on the substrate and then applies pressure by its own weight; or a forced pressurization mode in which the pressurizing component further descends and applies pressure during the process of the electronic component on the substrate being irradiated by a laser beam after the transparent pressurizing component initially contacts the electronic component on the substrate.

2. The pressurized type laser reflow soldering apparatus with vacuum chamber according to claim 1, wherein A carrier chuck is installed inside the vacuum chamber. After the substrate introduced from the inlet is moved to the area directly below the laser beam irradiation hole and laser reflow soldering is performed, the substrate that has undergone the laser reflow soldering process is moved to the outlet and led out of the vacuum chamber.

3. The laser reflow soldering apparatus with a vacuum chamber pressurization method according to claim 1, characterized in that, Two or more laser modules are arranged above the aforementioned vacuum chamber, and the laser beams irradiated from the aforementioned laser modules are superimposed on multiple electronic components arranged on the substrate through a light-transmitting pressurizing component.

4. The laser reflow soldering apparatus with a vacuum chamber pressurization method according to claim 1, characterized in that, When viewed from a plane, the aforementioned support portion forms a laser beam irradiation hole at its center, and the outer perimeter of the support portion forms a circular or symmetrical regular polygonal shape. With the center point of the aforementioned support portion as a reference, the arm portion is joined at the edge of the outer perimeter, which is equally divided into three parts. The aforementioned arm portion is connected to the pressure portion.

5. The laser reflow soldering apparatus with a vacuum chamber pressurization method according to claim 1, characterized in that, A roll-to-roll protective film transfer section is provided on the outside of the inlet and outlet of the aforementioned vacuum chamber, respectively, to prevent the protective film, which is rolled up in a roll shape, from adhering to the bottom surface of the light-transmitting pressurized component when the smoke generated during laser welding is applied, and to move it to one side.

6. The laser reflow soldering apparatus with a vacuum chamber pressurization method according to claim 5, characterized in that, The aforementioned switch is located at the bottom of the inlet or outlet and is in a standby state. When the inlet or outlet is closed, it slides upward and blocks the inlet or outlet with a protective film inserted to airtightly seal the interior of the vacuum chamber.

7. The laser reflow soldering apparatus with a vacuum chamber pressurization method according to claim 6, characterized in that, After the aforementioned switch is closed, the vacuum pump is driven to create a vacuum atmosphere inside the vacuum chamber.

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