KR102174930B1 - Laser pressure head module of laser reflow equipment - Google Patents

Abstract

The laser pressing head module of the laser reflow apparatus of the present invention is a laser bonding electronic components to a substrate by pressing a plurality of electronic components arranged on a substrate with a translucent pressing member and irradiating a laser beam through the pressing member. A laser pressurizing head module of a reflow device, wherein the translucent pressurizing member comprises: a base material having a rectangular panel shape as a whole; A pressing surface protruding from the bottom surface of the substrate so that the bottom surface corresponds to a plurality of electronic components; And at least one stepped portion formed between the substrate and the pressing surface and concave inward so that the area of the pressing surface is narrower than that of the substrate.

Description

Laser pressure head module of laser reflow equipment

The present invention relates to a laser reflow device, and more particularly, a quartz shape constituting a pressing head is divided and arranged in a grid shape so that a plurality of electronic components as a bonding object can be simultaneously pressed and pressed. It relates to a laser pressurizing head module of a laser reflow device capable of preventing light leakage of a laser beam at the edge of the.

Micro laser processing is an application field with micron (㎛) precision in industrial laser processing, and is widely used in the semiconductor industry, display industry, printed circuit board (PCB) industry, and smartphone industry. Memory chips used in all electronic devices have developed a technology that minimizes the circuit spacing in order to realize the integration, performance and ultra-high communication speed, but now the required technology level is achieved simply by reducing the circuit line width and line width interval. It is difficult to do so, so it has reached the level of stacking memory chips in a vertical direction. The stacking technology up to 128 layers has already been developed by TSMC, and the technology of stacking up to 72 layers is being applied to mass production at Samsung Electronics and SK Hynix.

In addition, technological developments for mounting memory chips, microprocessor chips, graphic processor chips, wireless processor chips, and sensor processor chips in one package are being intensively researched and developed, and a considerable level of technologies are already being applied in practice.

However, in the process of development of the aforementioned technology, since more and more electrons have to participate in the signal processing process inside the ultra-high-speed/ultra-high-capacity semiconductor chip, the power consumption increases, and the issue of cooling treatment for heat generation has been raised. In addition, a technical issue has been raised that a large amount of electrical signals must be transmitted at an ultra-high speed in order to achieve the requirements of ultra-high-speed signal processing and ultra-high frequency signal processing for more signals. In addition, since the number of signal lines must be increased, the signal interface lines to the outside of the semiconductor chip can no longer be processed with a one-dimensional lead wire method, but the Fan-In BGA method is processed in a two-dimensional manner under the semiconductor chip. Or Fan-in Wafer-Level-Package (FIWLP)), and a Signal Layout Redistribution Layer under the ultra-fine BGA layer under the chip, and a second fine BGA layer under the chip. The method (referred to as Fan-Out BGA or Fan-Out Wafer-Level-Package (FOWLP) or Fan-Out Panel-Level-Package) has been successfully applied.

Recently, in the case of semiconductor chips, products with a thickness of 200 μm or less including an EMC (Epoxy-Mold Compound) layer have appeared. In order to attach a micron-class ultra-thin semiconductor chip with a thickness of only a few hundred microns to an ultra-thin PCB, mass reflow is the same as the conventional surface mount technology (SMT) standard process, Thermal Reflow Oven technology. When applying MR) process, semiconductor chips are exposed in an air temperature environment of 100 to 300 degrees Celsius (℃) for hundreds of seconds, so chip-boundary warpage, PCB due to differences in coefficient of thermal expansion (CTE) -Various types of soldering bonding defects such as PCB-Boundary Warpage and Random-Bonding Failure by Thermal Shock may occur.

Accordingly, looking at the configuration of the laser reflow device that has recently been in the spotlight, the laser head module is a method of bonding by irradiating a laser while pressing an electronic component such as a semiconductor chip or an integrated circuit IC as a bonding object for several seconds. Alternatively, bonding is performed by irradiating a laser in the form of a surface light source corresponding to the size of the integrated circuit (IC).

For this pressurized laser head module, referring to Korean Patent No. 0662820 (hereinafter referred to as'priority document 1'), the flip chip is heated by irradiating a laser on the rear surface of the flip chip. A configuration of a flip-chip heating and compression module for compressing the carrier substrate is disclosed.

However, the laser head module of the conventional pressurization method as described above is separated into a means for adsorbing the chip and moving it to the bonding position, and a means for pressing the chip to the carrier substrate while heating the back surface of the chip through a laser. Therefore, in the case of bonding a plurality of semiconductor chips such as a semiconductor strip, the operation of irradiating a laser while pressing a single semiconductor chip must be repeatedly performed as many as the number of semiconductor chips, thereby increasing the working time.

Meanwhile, referring to Korean Patent Laid-Open Patent 2018-0137887 (hereinafter referred to as'priority document 2'), the laser pressure head configuration mentioned in the patent is in the horizontal direction while the pressure head presses several flip chips simultaneously. It briefly mentions that the bonding process is possible by irradiating a laser to each flip chip sequentially one by one or by irradiating a laser to several flip chips simultaneously by a single laser head.

However, according to the configuration of the conventional laser pressurizing head of Prior Document 2, it is not possible to irradiate and reflow a homogenized laser beam by simultaneously irradiating a single laser beam onto a plurality of flip chips at various angles using a single laser source. Technical difficulties are expected.

Therefore, if flip chips are sequentially processed one by one using a single laser source, the total working time is still inevitably increased. Even when a single laser source is irradiated to multiple flip chips at the same time, it is difficult to process a homogenized laser. Since the laser beam may leak out to the edge of the quartz constituting the pressing member, thermal damage is applied to the peripheral substrate of the flip chip due to the laser beam, and the problem of accelerating the deterioration of the substrate and the component still remains.

Accordingly, the present invention has been invented to solve the above problems. The present invention provides a laser reflow device with a large amount of processing possible and a significantly improved defect rate by irradiating a homogenized laser beam while simultaneously pressing a plurality of electronic components. It is an object to provide a laser pressure head module.

The present invention for achieving the above object is a laser reflow for bonding electronic components to a substrate by pressing a plurality of electronic components arranged on a substrate with a translucent pressing member and irradiating a laser beam through the pressing member. A laser pressurizing head module of an apparatus, wherein the translucent pressurizing member comprises: a base material having a rectangular panel shape as a whole; It is configured to include a pressing surface protruding from the bottom surface of the substrate and formed in a planar shape such that the bottom surface corresponds to a plurality of electronic components.

In addition, between the substrate and the pressing surface is configured to further include at least one step portion recessed inward so that the area of the pressing surface is narrower than that of the substrate.

In addition, according to an embodiment, the laser beam is composed of a single square laser beam having a uniform beam intensity.

In addition, according to another embodiment, the laser beam is formed by overlapping irradiation of at least two laser sources.

In addition, a laser light blocking layer is formed on the side surface and the bottom and side surfaces of the stepped portion of the substrate.

In addition, the pressing surface is divided into two or more by a grid groove having a predetermined depth.

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

In addition, the laser light blocking layer is composed of one of an Inconel coating layer, a diffuse reflection processing layer, or a high reflection (HR) coating layer, or a composite layer of two or more.

In addition, the light-transmitting pressing member is made of any one of quartz, sapphire, fused silica glass, or diamond.

In addition, the pressing surface has a square shape.

In addition, both corners of the pressing surface are chamfered or rounded.

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

In addition, the elastic damper layer is made of a silicon material.

In addition, a protective film is further included under the translucent pressurizing member to prevent fumes generated during laser bonding from sticking to the bottom surface of the translucent pressurizing member.

In addition, the protective film is implemented with polytetrafluoroethylene resin (PTFE) or perfluoroalkoxy resin (PFA).

In addition, the protective film is supplied in a reel-to-reel method in which the protective film wound in a roll shape is released and transferred to one side.

According to the present invention as described above, mass processing is possible by irradiating a homogenized laser beam while simultaneously pressing a plurality of electronic components, thereby greatly improving productivity.

In addition, the problem of accelerating the deterioration of the substrate and components due to thermal damage is applied to the peripheral substrate of the electronic component due to the laser beam leaking out to the edge of the quartz that constitutes the pressing member, thereby greatly reducing the defect rate. have.

1 is an exemplary view showing the overall configuration of a laser pressure head module of the laser reflow apparatus of the present invention
2 is a block diagram of FIG. 1
3 is a conceptual diagram of a single laser beam module according to an embodiment of the present invention laser pressure head module
4 is a conceptual diagram of a dual laser beam module according to another embodiment of the present invention laser pressure head module
5 is a configuration diagram of a dual laser beam module according to another embodiment of the present invention laser pressure head module
6 to 9 are configuration diagrams of a laser optical system applicable to a dual laser beam module according to another embodiment of the laser pressurizing head module of the present invention
10 is a perspective view of a main part showing a light-transmitting pressing member of the laser pressing head module of the present invention, (a) is an illustration of the shape of a light-transmitting pressing member having a single pressing surface according to one embodiment, (b) is a different embodiment. Example of the shape of a light-transmitting pressing member having a divided pressing surface to correspond to each electronic component accordingly
11 is an operational state diagram showing a state in which the translucent pressing member according to the present invention is mounted on the pressing head
12 is an enlarged view of a main part of FIG. 11
13 is a schematic diagram showing various embodiments of the translucent pressing member according to the present invention, (a) is a case where the pressing surface edge is not treated, (b) is a case where the pressing surface corner is chamfered, (c) is pressing When face edges are rounded

Terms used in the present specification are used only to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "include" or "have" to "include" are intended to designate the presence of features, numbers, steps, actions, components, parts, or a combination thereof described in the present specification. It is to be understood that the possibility of the presence or addition of other features, numbers, steps, actions, components, parts, or combinations thereof, or other features beyond that is not preliminarily excluded.

Unless otherwise defined in the specification, all terms including technical or scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs.

Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this specification. Shouldn't.

Hereinafter, a reflow device according to the present invention will be described in detail with reference to FIGS. 1 and 2.

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

The laser pressurizing head module 300 of the laser reflow apparatus according to the present invention, as shown in FIGS. 1 and 2, includes a porous material having a structure capable of applying heat to a lower portion or a stage 111 having a vacuum hole. ) At least one multi-laser module (310, 320) for irradiating a surface light source type laser to the bonding object 11 that is supported and transported, and is installed independently from the laser module 310, 320, and is a surface light source It is configured to include a light-transmitting pressurizing member 100 for transmitting the type of laser, and a protective film 200 for protecting the light-transmitting pressurizing member 100 from contamination.

First, the plurality of multi-laser modules 310 and 320 convert a laser generated by a laser oscillator and transmitted through an optical fiber into a surface light source to irradiate the bonding object 11. The laser modules 310 and 320 include a beam shaper that converts a spot-shaped laser into a surface light source (see FIG. 5), and a surface light source that is disposed under the beam shaper and emitted from the beam shaper is a bonding object ( 11) to be irradiated to the irradiation area of the plurality of lens modules may be implemented by including an optical unit (see FIGS. 5 to 9) mounted to be spaced apart from each other at appropriate intervals inside the barrel.

The laser modules 310 and 320 may rise or fall along the z-axis, move left or right along the x-axis, or move along the y-axis for alignment with the bonding object 11.

The pressure head 300 of the laser reflow apparatus according to the present invention includes a translucent pressure member 100 that presses the bonding object 11 and a laser module 310 and 320 that irradiates a surface light source type laser to the bonding object 11. ) Are formed to be separated from each other, and the laser modules 310 and 320 are moved to a plurality of irradiation positions of the bonding object 11 while pressing the bonding object 11 with the translucent pressing member 100 and then driven. By doing so, it is possible to shorten the tact time for one bonding object 11 and speed up the bonding operation for all of the plurality of bonding objects 11.

At this time, the light-transmitting pressing member 100 is moved to a working position or a standby position by a predetermined type of a light-transmitting pressing member conveying unit (not shown). For example, the translucent pressing member conveying unit lowers or It can be raised or moved to the left or right and then lowered or raised.

In addition, although not shown in the drawings, the laser pressure head module 300 of the laser reflow apparatus according to the present invention uses data input from a pressure sensor (not shown) and a height sensor (not shown) It further includes a control unit (not shown) for controlling the operation of the transfer unit.

The pressure sensing sensor and the height sensor may be installed on the light-transmitting pressing member 100, the light-transmitting pressing member transfer unit, and the stage 111 supporting the bonding object. For example, the controller may receive data from the pressure sensor and control the light-transmitting pressurizing member transfer unit so that the pressure reaches the target value, and also control the light-transmitting pressurization member transfer unit to receive data from the height sensor and reach the target height.

In addition, the support (not shown) supports the translucent pressing member transfer unit (not shown) to be movable. For example, the support unit may be implemented as a pair of gantry extending parallel to the stage 111, and includes a configuration that supports the translucent pressing member transfer unit to be movable in the x-axis, y-axis, or z-axis. It should be interpreted as being.

The pressure head 300 of the laser reflow device according to the present invention includes at least one actuator for applying pressure to the translucent pressurizing member 100 and at least one pressure sensing sensor that senses the pressure applied to the translucent pressurizing member 100 and a translucent It may be implemented by including one or more height sensors for detecting the height of the pressing member. As an example, the pressure sensor may be implemented with at least one load cell, and the height sensor may be implemented with a linear encoder.

By adjusting the pressure applied to the object to be bonded through the pressure sensor, in the case of a large area, it is possible to control so that the same pressure can be transmitted to the object to be bonded through a plurality of actuators and a plurality of pressure sensors. Through the height sensor, it provides technical data to check the height position value at the moment when the object to be bonded is bonded or to find a more accurate value of the bonding height. It performs a function that can be controlled.

In addition, the translucent pressing member 100 may be implemented as a base material that transmits the laser output from the laser modules 310 and 320. The base material of the light-transmitting pressing member 100 can be implemented with any beam-transmitting material.

The base material of the light-transmitting pressing member 100 may be implemented by any one of quartz, sapphire, fused silica glass, or diamond, for example. However, the physical characteristics of the light-transmitting pressing member made of quartz material are different from the physical characteristics of the light-transmitting pressing member made of sapphire. For example, when irradiating a 980nm laser, the transmittance of the translucent pressing member made of quartz material is 85% to 99%, and the temperature measured at the bonding object is 100°C. On the other hand, the transmittance of the light-transmitting pressing member made of sapphire is 80% to 90%, and the temperature measured on the object to be bonded is 60°C.

That is, in terms of light transmittance and heat loss required for bonding, quartz exhibits superior performance than sapphire. However, as a result of repeatedly testing the translucent pressurizing member 100 while developing the laser reflow device, the inventors of the present application have found that the translucent pressurizing member 100 implemented with a quartz material cracks during laser bonding. It has been found that there is a problem in that the bonding quality is defective due to the occurrence of burning on the bottom surface. It was analyzed that gases generated during laser bonding adhered to the bottom surface of the light-transmitting pressurizing member 100, and the heat source of the laser was concentrated in a portion to which the gas was adhered, thereby increasing thermal stress.

In order to prevent damage to the light-transmitting pressurizing member 100 made of a quartz material and improve durability, a thin film coating layer may be formed on the bottom surface of the light-transmitting pressurizing member made of a quartz material. The thin film coating layer formed on the bottom surface of the light-transmitting pressing member 100 may be implemented as a conventional optical coating, such as dielectric coating, SiC coating, or metallic material coating.

In the laser pressurizing head module 300 of the laser reflow apparatus according to the present invention, as shown in FIG. 1, gases generated during laser bonding are transmitted to the lower portion of the translucent pressurizing member 100. ) Is implemented to further include a protective film 200 that prevents sticking to the bottom surface of the protective film 200 and a protective film transport unit 210 for transporting the protective film 200.

The protective film transfer unit 210 may be implemented in a reel-to-reel method in which the protective film 200 wound in a roll shape is released and transferred to one side. The protective film 200 is, for example, a maximum use temperature of 300 degrees Celsius or more, and a continuous maximum use temperature of 260 degrees or more, and is preferably implemented with a material having excellent heat resistance. For example, the protective film 200 may be implemented with polytetrafluoroethylene resin (commonly referred to as Teflon resin; Polytetrafluoroethylene, PTFE) or purple alkoxy resin. Per Fluoro Alkylvinyether copolymer (PFA) is a product that improves the heat resistance of fluorinated ethylene propylene resin, and it is a high-functional resin with the highest continuous use temperature recorded at 260 degrees Celsius like polytetrafluoroethylene resin.

3 is a conceptual diagram of a single laser module according to an embodiment of the present invention bonding object transport module, Figure 4 is a conceptual diagram of a dual laser module according to another embodiment of the present invention bonding object transport module.

Referring to FIG. 3, the present invention includes a single laser module 310 according to an embodiment, and thus a single laser beam is irradiated on the FPCB substrate. In this case, referring to FIG. 3, the laser beam irradiated by the first laser module 310 is irradiated on the substrate in a state in which the intensity of the laser beam is transformed into a uniform square beam shape.

Meanwhile, referring to FIG. 4, a multi-laser module according to another embodiment of the present invention includes, for example, a first laser module 310 and a second laser module 320, and is an electronic component of the bonding object 11. At this attachment position, the first and second laser modules are irradiated in a superimposed state to irradiate a homogenized superimposed laser beam.

In FIG. 4, the first laser beam has a square shape and the second laser beam has a circular shape, but both laser beams may have a square shape. In addition, the first laser beam and the second laser beam may be irradiated at the same time, or the second laser beam may be sequentially irradiated after preheating of the bonding object 11 by the first laser beam.

5 is a block diagram of a dual laser module according to another embodiment of the present invention pressure head.

In Figure 5, each laser module (310, 320, ... 330) is a laser oscillator (311, 321, 331), each having a cooling device (316, 326, 336), beam shaper (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.

Hereinafter, except for a case where necessary, the first laser module 310 of each laser module having the same configuration will be mainly described in order to avoid redundant description.

The laser oscillator 311 generates a laser beam having a wavelength and output power in a predetermined range. The laser oscillator is, for example, a diode laser (Laser Diode, LD) having a wavelength of '750nm to 1200nm' or '1400nm to 1600nm' or '1800nm to 2200nm' or '2500nm to 3200nm', or a rare earth medium fiber laser (Rare-Earth- Doped Fiber Laser) or rare-earth-doped crystal laser (Rare-Earth-Doped Crystal Laser), alternatively, a medium for emitting alexandrite laser light having a wavelength of 755 nm, or Nd Yag (Nd) having a wavelength of 1064 nm or 1320 nm. :YAG) It may be implemented including a medium for emitting laser light.

The beam shaper 312 converts a spot-shaped laser generated in a laser oscillator and transmitted through an optical fiber into an area beam having a flat top. The beam shaper 312 may be implemented by including a Square Light Pipe, a Diffractive Optical Element (DOE), or a Micro-Lens Array (MLA).

The optical lens module 313 adjusts the shape and size of the laser beam converted to the surface light source form by the beam shaper to irradiate the electronic component or the irradiation area mounted on the PCB substrate. The optical lens module constitutes an optical system by combining a plurality of lenses, and a specific configuration of such an optical system will be described later in detail with reference to FIGS. 6 to 9.

The driving device 314 moves the distance and position of the laser module with respect to the irradiation surface, and the control device 315 controls the driving device 314 to control the beam shape and the beam area size when the laser beam reaches the irradiation surface. , Adjust the beam sharpness and beam irradiation angle. The control device 315 may also integrally control the operation of each unit of the laser module 310 in addition to the driving device 314.

Meanwhile, the laser power adjustment unit 370 is supplied to each laser module from the power supply units 317, 327, 337 corresponding to each laser module 310, 320, 330 according to a program received through a user interface or a preset program. Controls the amount of power to be used. The laser output adjustment unit 370 receives information on the reflow status of each part, area, or entire reflow on the irradiation surface from one or more camera modules 350 and controls each power supply unit 317, 327, 337 based on this. In contrast, the control information from the laser output control unit 370 is transmitted to the control devices 315, 325, 335 of each laser module (310, 320, 330), and each control device (315, 325, 335) It is also possible to provide a feedback signal for controlling the corresponding power supply unit 317. In addition, unlike FIG. 6, it is possible to distribute power to each laser module through one power supply unit. In this case, the power supply unit must be controlled by the laser output adjustment unit 370.

When implementing the laser superimposition mode, the laser power adjustment unit 370 includes each laser module and the laser module so that the laser beam from each laser module 310, 320, 330 has a required beam shape, a beam area size, beam sharpness, and beam irradiation angle. Controls the power supply units 317, 327, 337. In addition to the case of preheating the area around the debonding target location using the first laser module 310 and additionally heating the narrower reflow target area using the second laser module 320, the preheating function or The additional heating function is appropriately distributed among the first, second, and third laser modules 310, 320, ... 330 to control each laser module to have a required temperature profile.

Meanwhile, when a single laser light source is distributed and input to each laser module, a function for simultaneously adjusting the output and phase of each distributed laser beam may be provided in the laser output adjusting unit 370. In this case, the beam flatness can be remarkably improved by controlling the phase to induce destructive interference between the respective laser beams, thereby further increasing energy efficiency.

On the other hand, in the case of implementing a multi-position simultaneous processing mode, the laser power adjustment unit 370 is used to ensure that some or all of the laser beams from each laser module are different. Controls one or more of the angle and beam wavelength. Even at this time, when a single laser light source is distributed and input to each laser module, a function for simultaneously adjusting the output and phase of each distributed laser beam may be provided in the laser output adjusting unit 370.

Through this function, bonding between the electronic components in the irradiation surface and the substrate can be performed or the bonding can be removed by adjusting the laser beam size and output. In particular, in the case of removing damaged electronic components on the substrate, the application of heat by the laser beam to other adjacent electronic components or normal electronic components existing on the substrate can be minimized by minimizing the area of the laser beam to the corresponding electronic component area. Thus, it is possible to remove only the damaged electronic component to be removed.

On the other hand, in the case of emitting laser beams with different wavelengths for each of the plurality of laser modules, the laser module will absorb a plurality of material layers (e.g., EMC layer, silicon layer, solder layer) included in the electronic component. It can be composed of individual laser modules with wavelengths. Accordingly, the laser debonding device according to the present invention selectively increases the temperature of the electronic component and the temperature of the intermediate bonding material such as solder, which is a connection material between the printed circuit board or the electrode of the electronic component. Bonding) or separation (detaching or debonding) process may be performed. Specifically, by transmitting both the EMC mold layer and the silicon layer of the electronic component, all the energy of each laser beam is absorbed into the solder layer, or the laser beam does not penetrate the EMC mold layer and heats the surface of the electronic component to It is also possible to conduct heat to the bonding portion of.

Meanwhile, by utilizing the above functions, a predetermined area of the electronic component to be reflowed and a predetermined area of the substrate including the periphery thereof is preheated to a predetermined preheating temperature by at least one first laser beam, and then the at least one second laser beam is applied. Accordingly, the temperature of the electronic component region to be reflowed is selectively heated up to the reflow temperature at which solder melting occurs.

6 to 9 are configuration diagrams of a laser optical system applicable to a single laser beam or a multi-laser module of the bonding object transfer module of the present invention.

6 is an optical system having the simplest structure applicable to the present invention. When the laser beam emitted from the beam transmission optical fiber 410 is focused through the convex lens 420 and incident on the beam shaper 430, the beam shaper 430 ), the spot-shaped laser beam is converted into a flat-top type surface light source (A1), and the square laser beam (A1) output from the beam shaper 430 is the desired size through the concave lens 440 The image-forming surface S is irradiated with the enlarged surface light source A2.

7 is a block diagram of a laser optical system according to another embodiment of the present invention.

The surface light source B1 from the beam shaper 430 is enlarged to a predetermined size through the concave lens 440 to become a surface light source B2 irradiated to the first imaging surface S1. When the surface light source (B2) is to be further enlarged and used, the boundary of the edge portion of the surface light source (B2) may become more unclear according to the additional enlargement, so that the final irradiation surface is the second imaging surface (S2). ) Also, in order to obtain irradiation light with a clear edge, a mask 450 is installed on the first imaging surface S1 to trim the edge.

The surface light source passing through the mask 450 is reduced (or enlarged) to a desired size while passing through the zoom lens module 460 composed of a combination of at least one convex lens and a concave lens, and the second imaging surface on which the electronic component is placed Square irradiation light B3 is formed in (S2).

8 is a block diagram of a laser optical system according to another embodiment of the present invention.

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

Here, the cylindrical lens is a shape obtained by cutting a cylindrical shape in the longitudinal direction, and functions to expand or reduce the laser beam according to the shape in which each lens is arranged in the vertical direction, and the lens on the surface on which the cylindrical lens is placed is x, y Depending on the shape arranged in the axial direction, the laser beam is adjusted in the x-axis or y-axis direction.

Subsequently, the surface light source C3 is enlarged (or reduced) to a desired size while passing through the zoom lens module 460 composed of a combination of at least one convex lens and a concave lens, and the second imaging surface S2 on which the electronic component is disposed. ) To form a rectangular irradiation light C4.

9 is a configuration diagram of a laser optical system according to another embodiment of the present invention.

It is understood that the optical system of FIG. 9 has a configuration for trimming the edge of the laser beam by applying a mask to the optical system of FIG. 8, and it is understood that a final surface light source D5 having a sharper edge can be obtained compared to the case of FIG. 8. I will be able to.

10 is a perspective view of a main part showing a light-transmitting pressing member of the laser pressing head module of the present invention, (a) is an illustration of the shape of a light-transmitting pressing member having a single pressing surface according to one embodiment, (b) is a different embodiment. Accordingly, the shape of a light-transmitting pressing member having a pressing surface divided to correspond to each electronic component is illustrated.

Hereinafter, looking at the structure of the light-transmitting pressing member 100 according to an embodiment of the present invention with reference to FIGS. 10A and 10B, the light-transmitting pressing member 100 of the present invention is a rectangular plate-shaped substrate 101 as shown in FIG. 10A. The pressing surface 102 of a certain area has a structure protruding on the top. The area of the pressing surface 102 is preferably designed to correspond to the processing area of the bonding object 11 in consideration of the area of the bonding object 11 to be laser reflow-processed at a time by a predetermined area.

In this case, the area of the pressing surface 102 is formed to be narrower than the area of the substrate 101, and has at least one or more stepped portions 101a around the pressing surface 102. In addition, a laser light blocking layer 103 (shaded display) is further formed on the side surface of the substrate 101 and the bottom and side surfaces of the step portion 101a except for the pressing surface 102 to prevent light leakage of the laser beam.

Meanwhile, referring to FIG. 10B, looking at the structure of the light-transmitting pressing member 100 according to another embodiment of the laser pressing head module of the present invention, in FIG. 10A, a single pressing surface 102 is formed, but in FIG. 10B, a bonding object In order to contact and press the plurality of electronic components included in (11), respectively, the pressing surface 102 has a structure divided into a grid shape so as to correspond to the area of each electronic component. To this end, in the structure shown in FIG. 10B, it is necessary to design and process the pressing surface 102 so as to accurately correspond to the occupied area of each electronic component to be laser reflowed.

In this case, as shown in FIG. 10B, a laser light blocking layer 103 (shaded display) is formed on the side of the substrate 101 other than the plurality of pressing surfaces 102 divided in a grid shape, and the bottom and side surfaces of the step 101a. More formed.

The laser light blocking layer 103 can generally be formed of various types of special coating layers that absorb or reflect light, for example, an Inconel coating layer that absorbs a laser beam, or a frosted glass type. It may be implemented as one of a diffuse reflection processing layer or a high reflection (HR) coating layer that reflects a laser beam, or a composite layer of two or more. By coating the laser light blocking layer 103, the laser beam is accurately irradiated only to the electronic component of the bonding object 11 through the pressing surface 102 of the translucent pressing member 100, so that a nearby flexible circuit in the vicinity of the electronic component Thermal damage and subsequent damage to the substrate by irradiating the laser beam to the substrate (FPCB) portion is also prevented.

11 is an operational state diagram showing a state in which the light-transmitting pressing member according to the present invention is mounted on the pressing head, and FIG. 12 is an enlarged view of a main part of FIG. 11.

11 and 12, in the light-transmitting pressing member 100 of the present invention, a pressing surface 102 having an area smaller than that of the base material protrudes on the bottom surface of the rectangular base material 101 as described above. Has a structure. At this time, at least one stepped portion 131a is formed between the substrate 101 and the pressing surface 102, and as shown in FIG. 11, the stepped portion 101a ripples the light-transmitting pressing member 100. It is used for mounting on the holder unit 500 of the row device.

Meanwhile, a silicon damper layer 104 may be further formed on the pressing surface 102. In general, electronic components disposed on a flexible circuit board (FPCB) constituting the bonding object 11 are not completely flat due to the characteristics of the flexible circuit board and have their own curvature. Accordingly, each of the electronic components may be understood as being disposed at different heights instead of at the same height on the horizontal line along the curved surface of the flexible circuit board.

At this time, when the pressing surface 102 of the transparent pressing member 100 simultaneously presses and presses electronic components positioned at different heights from the curved surface of the flexible circuit board for bonding, the electronic components at a relatively high position are A higher pressing force is applied than electronic components located at a lower position, and thus, solder located below the electronic components located at a higher position may not be normally reflowed due to excessive pressing force, and bonding failure may be caused.

To this end, the silicon damper layer 104, which is a light-transmitting elastic body, is additionally formed on the pressing surface 102 according to an embodiment of the present invention, so that even if an excessive pressing force acts on the electronic components located above, the silicon damper layer 104 is It performs a damping function that absorbs a certain amount of excessive pressing force.

Meanwhile, when the translucent pressing member 100 presses the electronic component, a laser beam is irradiated from the first or second laser modules 310 and 320 located above the translucent pressing member 100, and the The laser beam is irradiated to the electronic component through the light-transmitting pressing member 100 so that heat energy for reflow is transmitted.

Referring to FIG. 12, when a laser beam is irradiated through the translucent pressing member 100, a laser light blocking layer 103 (shaded) is formed on the side surface of the substrate 101 and the bottom and side surfaces of the step portion 101a. As a result, the laser beam is blocked from leaking to all other parts except the pressing surface 102 as a result.

In addition, for uniform laser reflow processing, in the present invention, the shape and protrusion height of the pressing surface 102 are also presented as major considerations when designing the translucent pressing member 100. For example, as shown in FIG. 10A, if the pressing surface 102 is not formed in a square structure, but if it is formed in a rectangular structure, the side area on the long side will be larger than on the short side of the rectangle. It is predictable that heat energy is lost more rapidly.

When such a heat loss phenomenon occurs, thermal energy cannot be uniformly transmitted to the plurality of electronic components that are pressed while being placed under the pressing surface 102, so that bonding failure occurs in electronic components that are lower or higher than the proper bonding temperature. It is more likely to be. Accordingly, according to a preferred embodiment, as the shape of the bottom surface of the pressing surface 102 is designed in a square structure, heat dissipation through the side surfaces of the pressing surface 102 is uniformly performed in the vertical and horizontal directions.

In addition, even if the side protrusion height h of the pressing surface 102 is formed too high, there is a possibility that a lot of heat loss through the side of the step portion 101a may occur, so the protrusion height h of the pressing surface 102 Alternatively, it is most preferable to minimize the depth of the grating groove 102a concave between the divided pressing surfaces 102 to within several mm.

On the other hand, Figure 13 is a schematic diagram showing various embodiments of the light-transmitting pressing member according to the present invention, (a) is a case where the pressing surface edge is not processed, (b) is a case where the pressing surface corner is chamfered, (c) is This is the case where the corners of the pressing surface are rounded.

13a, b, and c, a protective film 200 is provided under the light-transmitting pressurizing member 100 of the present invention to prevent adsorption of fumes, as shown in FIG. 2 above. Same as one. At this time, as shown in FIG. 13A, when the light-transmitting pressing member 100 is moved downward to press the bonding object 11, the protective film 200 is also pressed together by the light-transmitting pressing member 100, and at this time, the pressing surface ( It is understandable that the protective film 200 is in contact with both corners of 132).

However, as described above, if the protective film 200 repeatedly contacts both corners of the pressing surface 102, it is predictable that the protective film 200 may eventually be torn or damaged.

Therefore, in order to prevent such a closing, in the present invention, both corners of the pressing surface 102 are chamfered as shown in FIG. 13B so that the protective film is not damaged by both corners of the pressing surface 102 or shown in FIG. 13C. As described above, by rounding both corners, additional considerations are presented in the design of the translucent pressing member 100.

In addition, the present invention is not limited only by the above-described embodiment, and since the same effect can be created even when the detailed configuration, number, and arrangement structure of devices are changed, those of ordinary skill in the art can create the present invention. It is stated that various configurations can be added, deleted, and modified within the scope of the technical idea of

100: light-transmitting pressing member 101: substrate
101a: step portion 102: pressing surface
102a: grating groove 103: laser light blocking layer
104: silicon damper layer 500: holder unit
310: first laser module 320: second laser module

Claims (16)

A laser pressing head module of a laser reflow apparatus for bonding electronic components to a substrate by pressing a plurality of electronic components arranged on a substrate with a translucent pressing member and simultaneously irradiating a laser beam through the pressing member,
The translucent pressing member,
A substrate having a rectangular panel shape as a whole;
It includes a pressing surface that is formed protruding from the bottom of the substrate and is divided into two or more grids on a plane by a grid groove having a predetermined depth so that the bottom surface corresponds to a plurality of electronic components,
At least one stepped portion is formed between the substrate and the pressing surface so that the area of the pressing surface is narrower than that of the substrate,
In addition to the plurality of pressing surfaces divided in the grid shape, the side surfaces of the substrate and the bottom and side surfaces of the stepped portion, and the inner side and bottom of the grid groove are inconel coating layers, diffuse reflection processing layers, or HR Reflection) By further forming a laser light blocking layer composed of one or more composite layers among the coating layers,
Characterized in that the laser beam incident through the substrate is accurately irradiated only to the electronic component of the bonding object through the pressing surface of the translucent pressing member,
Laser pressurization head module of the laser reflow device. delete The method of claim 1,
The laser beam is a single square laser beam in which the intensity of the beam is homogenized,
Laser pressurization head module of the laser reflow device. The method of claim 1,
The laser beam is formed by overlapping irradiation of at least two laser sources,
Laser pressurization head module of the laser reflow device. delete delete delete delete The method of claim 1,
The translucent pressing member is implemented with any one of quartz, sapphire, fused silica glass, or diamond,
Laser pressurization head module of the laser reflow device. The method of claim 1,
The pressing surface has a square shape,
Laser pressurization head module of the laser reflow device. The method of claim 10,
Both corners of the pressing surface are chamfered or rounded,
Laser pressurization head module of the laser reflow device. The method of claim 1,
An elastic damper layer is further provided on the pressing surface,
Laser pressurization head module of the laser reflow device. The method of claim 12,
The elastic damper layer is implemented with a silicon material,
Laser pressurization head module of the laser reflow device. The method of claim 1,
Further comprising a protective film below the translucent pressurizing member to prevent fumes generated during laser bonding from sticking to the bottom surface of the translucent pressurizing member,
Laser pressurization head module of the laser reflow device. The method of claim 14,
The protective film is implemented with polytetrafluoroethylene resin (PTFE) or perfluoroalkoxy resin (PFA),
Laser pressurization head module of the laser reflow device. The method of claim 14,
The protective film is supplied in a reel-to-reel method, which is transferred to one side while unwinding the protective film wound in a roll form,
Laser pressurization head module of the laser reflow device.

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