Laser-assisted microball repair system using side vision camera and thermal imaging camera.

Abstract

This invention provides a laser-automatic recipe-compatible microball repair device that prevents the occurrence of defective microballs and enables the formation of good microballs. [Solution] The microball repair apparatus supporting laser auto-recipe comprises a working stage on which a PCB is placed and the microball repair process is executed, a solder ball placement unit that picks up solder balls and attaches them to the position where the repair process is executed, a laser optical module that irradiates the attached solder balls with a surface light source laser to form microballs, and a laser recipe control unit 700 that controls the laser irradiation output and irradiation time. The laser optical module further includes a side vision camera 560 and a thermal imaging camera 600, and the laser recipe control unit automatically controls the laser recipe based on the side view image captured by the side vision camera and the temperature image captured by the thermal imaging camera.

Description

Technical Field

[0001] The present invention relates to a micro ball repair device that supports a laser auto recipe using a side vision camera and a thermal image camera. More specifically, the present invention relates to a micro ball repair device that analyzes the state of a micro ball using a side vision camera and a thermal image camera, and automatically controls a laser recipe according to the state of the micro ball, thereby preventing defective manufacturing of the micro ball.

Background Art

[0002] The reflow process is one of the main processes of surface mount technology (SMT) and is related to the technical field of applying thermal energy to electrically join a semiconductor element and a substrate. For example, a structure in which a semiconductor element is joined to a substrate by applying heat to a semiconductor element mounted on a solder ball formed on a substrate is used.

[0003] For this purpose, it is a prerequisite that solder balls are arranged in a good state on a substrate with a pre-designed pattern. However, due to defects in the substrate manufacturing process, solder balls may be missing or defective, and a repair device for repairing such missing or defective solder balls is required.

[0004] Conventionally, in order to address such problems, a method has been used in which a missing ball is attached to a substrate and bonding is performed using spot laser irradiation.

[0005] However, a conventional spot laser has a Gaussian-type energy distribution in which the energy intensity increases toward the center of the irradiation region. Therefore, there are problems that energy higher than the melting temperature of the solder ball is locally concentrated to cause defects due to thermal shock, and it is difficult to supply sufficient thermal energy as the distance from the irradiation region increases.

[0006] One proposed solution to this problem is an area laser structure that corresponds to the area to be repaired. An area laser can irradiate a predetermined area with uniform laser light, making it possible to apply uniform thermal energy.

[0007] On the other hand, in recent years, semiconductors have become extremely highly integrated with the development of high-performance memory, artificial intelligence semiconductors, and high-performance AP chips, and in response to this, solder balls on substrates are now mounted at a fine pitch, with the size of micrometers.

[0008] Furthermore, with increasing density and complexity of substrate patterns, multilayer substrates with multiple layers are widely used. To repair microballs on such fine-pitch, multilayer substrates, a repair device capable of precise irradiation position control and laser recipe control (laser output and irradiation time) is required.

[0009] Therefore, in order to repair missing or defective microballs in fine and complex substrate structures, there is a need for a microball repair device that can perform ultra-precise control and laser recipe control. [Prior art documents] [Patent Documents]

[0010] Korean Published Patent No. 10-2022-0014940 Korean Published Patent No. 10-2006-0015023 [Overview of the project] [Problems that the invention aims to solve]

[0011] The technical problem that this invention aims to solve is to provide a microball repair device that can prevent the occurrence of defective microballs and form good microballs by analyzing the state of the microballs by analyzing changes in size, position, reflection characteristics, and shape of the microballs using a side vision camera, and by detecting temperature changes of the microballs using a thermal imaging camera, and by controlling the laser auto-recipe (laser output, irradiation time, and laser power) according to that state.

[0012] Another technical problem that this invention aims to solve is to provide a microball repair device that can prevent the occurrence of defective microballs and form good microballs by stopping laser irradiation regardless of whether a set duration of laser irradiation has elapsed when the temperature of the microball or PCB substrate captured by a thermal imaging camera reaches a predetermined threshold.

[0013] Furthermore, the problems addressed by this invention are not limited to those described above, and any person with ordinary skill in the art to which this invention belongs can easily understand other problems from the following description. [Means for solving the problem]

[0014] To achieve the aforementioned technical objectives, according to one embodiment of the present invention, a microball repair apparatus that supports laser auto-recipe includes: a working stage on which a PCB is placed and on which a microball repair process is performed; a solder ball placement unit that picks up solder balls and attaches them to the position where the repair process is performed; a laser optical module that irradiates the attached solder balls with a surface light source laser to form microballs; and a laser recipe control unit that controls the laser irradiation output and irradiation time.

[0015] The laser optical module further includes a side vision camera and a thermal imaging camera, and the laser recipe control unit can automatically control the laser recipe using the side view image captured by the side vision camera and the temperature image captured by the thermal imaging camera.

[0016] Furthermore, the laser recipe control unit may include: a side vision image analysis unit that analyzes at least one of the following over time: changes in size, position, reflected light, and shape of the microballs from side view images of the microballs and the PCB substrate captured by the side vision camera; a thermal image analysis unit that analyzes temperature changes of the PCB substrate or the microballs captured by the thermal image camera; a microball state analysis unit that analyzes the state of the microballs based on the information analyzed by the side vision image analysis unit and the thermal image analysis unit; and a laser recipe determination unit that determines the laser output, laser irradiation time, and laser power to be irradiated onto the microballs based on the state of the microballs.

[0017] The side vision image analysis unit may include a position change analysis unit that detects vertical and horizontal position changes of the microballs due to laser irradiation, and a reflection characteristics analysis unit that detects changes in brightness and size of the reflective surface of the microballs due to laser irradiation.

[0018] Furthermore, the side vision image analysis unit may further include a size change analysis unit for detecting size changes of the microballs due to laser irradiation, and a shape analysis unit for detecting shape changes of the microballs due to laser irradiation.

[0019] The reflection characteristic analysis unit can detect the values ​​of the changes in brightness and size of the reflective surface of the microballs due to the melting of the microballs caused by the laser irradiation.

[0020] In addition, the shape analysis unit can detect a value indicating that the shape of the micro ball has changed from a spherical shape to a dome shape due to the melting of the micro ball caused by the laser irradiation.

[0021] Furthermore, the laser recipe determination unit can determine the output and duration of the laser irradiation according to the melting state of the micro ball analyzed by the micro ball state analysis unit.

[0022] In addition, when the temperature of the PCB substrate or the micro ball reaches a predetermined threshold value, the laser recipe determination unit can generate a laser off trigger to stop the operation of the laser irradiated on the micro ball.

Advantages of the Invention

[0023] According to the embodiment of the present invention, by using a side vision camera to analyze the size change, position change, reflection characteristic change and shape change of the micro ball, and using a thermal imaging camera to detect the temperature change of the micro ball, analyzing the state of the micro ball based on this information, and controlling the auto recipe (laser output, irradiation time and laser power) of the laser irradiated on the micro ball according to the state of the micro ball, it is possible to prevent the occurrence of defects in the micro ball and form a good micro ball.

[0024] In addition, according to the embodiment of the present invention, when the temperature of the micro ball or the PCB substrate photographed by the thermal imaging camera reaches a predetermined threshold value, by stopping the laser irradiation regardless of whether the set duration of the laser irradiation has elapsed, it is possible to prevent the occurrence of defects in the micro ball and form a good micro ball.

[0025] It should be noted that the effects of the present invention are not limited to the above, and it should be understood that all effects inferable from the configurations described in the description or claims of the present invention are included.

Brief Description of the Drawings

[0026] [Figure 1] It is a block diagram showing the configuration of a micro ball repair device according to an embodiment of the present invention. [Figure 2] It is a perspective view showing a micro ball repair device realized by an embodiment of the present invention. [Figure 3] It is a diagram showing a cross section of a laser optical module according to an embodiment of the present invention. [Figure 4] It is a diagram showing the detailed configuration and specifications of an optical unit according to an embodiment of the present invention. [Figure 5] It is a diagram showing a laser optical module and a thermal imaging camera additionally provided with a side vision camera according to an embodiment of the present invention. [Figure 6] It is a block diagram showing the detailed configuration of a laser recipe control unit according to an embodiment of the present invention. [Figure 7] It is a block diagram showing the detailed configuration of a side vision image analysis unit according to an embodiment of the present invention. [Figure 8] It is a diagram showing images before and after laser irradiation on a micro ball using a side vision camera and a thermal imaging camera according to an embodiment of the present invention. [Figure 9] It is a flowchart showing an operation method of a micro ball repair device according to an embodiment of the present invention. [Figure 10] It is a flowchart showing an image analysis method using a side vision camera in a micro ball repair device according to an embodiment of the present invention. [Figure 11] It is a flowchart showing a detailed method of controlling a laser recipe in a micro ball repair device according to an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0027] The present invention will be described below with reference to the attached drawings. It should be noted that the present invention can be embodied in various different forms and is therefore not limited to the embodiments described herein. Furthermore, in order to clearly illustrate the present invention, parts unrelated to the description have been omitted from the drawings, and similar parts throughout the specification are denoted by the same reference numerals.

[0028] When a part of the specification is described as being "connected (connected, in contact with, or joined)" to another part, that description includes not only cases where the parts are "directly connected" but also cases where they are "indirectly connected" through other components in between. Furthermore, when a part is described as "including" a component, that description does not exclude other components unless otherwise stated, but rather means that it may further include other components.

[0029] The terms used herein are used solely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “includes” or “equipment” should be understood to mean the presence of features, figures, stages, operations, components, parts, or combinations thereof described in the specification, and not to presuppose the presence or possibility of adding one or more other features, figures, stages, operations, components, parts, or combinations thereof.

[0030] The embodiments of this invention will be described in detail below with reference to the attached drawings.

[0031] Figure 1 is a block diagram showing the configuration of a microball repair device according to an embodiment of the present invention. Figure 2 is a perspective view showing a microball repair device realized according to an embodiment of the present invention.

[0032] As shown in Figure 1 or Figure 2, the microball repair apparatus (1000) is a device that repairs microballs using a surface light source laser, and may include a PCB conveyor (100), a working stage (200), a flux application unit (300), a solder ball placement unit (400), a laser optical module (500), a thermal imaging camera (600), and a laser recipe control unit (700).

[0033] First, the PCB conveyor (100) can transport PCBs loaded from a PCB loader (not shown) to a PCB unloader (not shown) on the opposite side via a working stage (200). The working stage (200) functions as a product placement area, where PCBs transported via the PCB conveyor (100) are placed, and the microball repair process is performed.

[0034] The flux application unit (300) is located near the working stage (200), and a jetting valve can apply flux to the solder ball position to be repaired. Once flux is applied to the repair position, the solder ball nozzle of the solder ball placement unit (400) can pick up the solder ball and attach it to the flux application position.

[0035] The laser optical module (500) is configured to be movable in a first direction (e.g., the X-axis direction), and the working stage (200) can focus on the position of the microballs to be repaired on the mounted PCB while moving in a second direction (e.g., the Y-axis direction) orthogonal to the first direction. The position of the microballs to be repaired may be determined in advance using the results of image analysis of the microballs formed on the PCB and PCB design data (e.g., Gerber files, ODB++ files, etc.), or it may be determined in real time.

[0036] The laser optical module (500) can form microballs by irradiating attached solder balls with laser beams using multiple coaxially arranged surface source lasers having different wavelengths and irradiation areas. In addition to the multiple surface source lasers, the laser optical module (500) can also be equipped with a coaxially mounted vertical vision camera. Images captured by this vision camera can be used for monitoring the attachment position of the solder balls, monitoring the melting state of the solder balls, and controlling the laser recipe.

[0037] The specific configuration of the laser optical module (500) will be described later with reference to Figure 3. The thermal imaging camera (600) can measure the temperature of the PCB substrate or microballs in real time before and after laser irradiation. The laser recipe control unit (700) can control the laser recipe by analyzing the microball images captured by the coaxial vision camera of the laser optical module (500) or an additionally provided side vision camera.

[0038] Furthermore, the laser recipe control unit (700) can control the laser recipe by analyzing temperature measurement images of the PCB substrate or microballs captured by the thermal imaging camera (600).

[0039] Here, the laser recipe in the laser recipe control unit (700) includes the irradiation output and irradiation time of multiple surface light source lasers. When repairing microballs with fine pitch on a multilayer PCB substrate having a multilayer structure, the laser recipe is not fixed but is set variably according to the state of each microball.

[0040] Therefore, the laser optical module (500), the thermal imaging camera (600), and the laser recipe control unit (700) operate in conjunction with each other, and the laser recipe control unit (700) can control the execution of the process based on the result values ​​obtained from the laser optical module (500) and the thermal imaging camera (600).

[0041] With the configuration described above, the microball repair device (1000) performs reflow and monitoring for precise microball repair using a laser optical module (500), and the laser recipe control unit (700) controls the reflow operation of the laser optical module (500) using vision and temperature images of the microballs.

[0042] As a result, the microball repair device (1000) can efficiently utilize a limited space to position the laser optical module (500) and perform a precise bonding process on a micrometer scale. Furthermore, it enables automatic control of the laser recipe based on real-time image analysis.

[0043] Figure 3 shows a cross-section of a laser optical module according to an embodiment of the present invention.

[0044] As shown in Figure 3, the laser optical module (500) may include a first-plane light source laser unit (510), a second-plane light source laser unit (520), a coaxial vision camera unit (530), a window unit (540), and an optical unit (550).

[0045] First, the first surface light source laser unit (510) can be used for reflow solder balls, and laser light having a wavelength of 808 nm is incident on the first incident unit (511), and a first surface light source laser beam having a wavelength of 808 nm can be emitted.

[0046] Here, the first injector (511) is formed with a diameter of 70 μm, and the output can be set to 5W or less.

[0047] The second surface light source laser section (520) can be used for preheating and may include a second incident section (521) and a rectangular beam conversion section (522).

[0048] A circular laser beam with a wavelength of 980 nm is incident on the second incident section (521), and in the rectangular beam conversion section (522), it is converted into a second surface light source laser beam with a wavelength of 980 nm and emitted.

[0049] Here, the second injection section (521) is set to a diameter of 105 μm, the rectangular beam conversion section (522) is formed with sides of 1,350 μm, and the output can be set to 200 W or less.

[0050] The first surface light source laser unit (510) and the second surface light source laser unit (520) are arranged in a parallel structure to each other, and can emit rectangular surface light source laser beams of different wavelengths from each other.

[0051] Furthermore, the surface light source laser beams from the first surface light source laser unit (510) and the second surface light source laser unit (520) can be emitted simultaneously or sequentially at their respective wavelengths.

[0052] The coaxial vision camera unit (530) can monitor the position and state of solder balls from the vertical direction of the PCB substrate and provide the monitored information to the laser recipe control unit (700).

[0053] The coaxial vision camera unit (530) can be positioned on one side of the first surface light source laser unit (510). Preferably, in order to efficiently utilize space, the optical path of the coaxial vision camera unit (530) to the image sensor can be positioned parallel to the first surface light source laser unit (510) and the second surface light source laser unit (520).

[0054] The coaxial vision camera unit (530) is focused coaxially with the central axis of the first and second surface light source laser beams emitted from the first surface light source laser unit (510) and the second surface light source laser unit (520), and captures vision images.

[0055] The window section (540) can transmit the wavelengths of the first and second surface light source laser beams emitted from the first surface light source laser section (510) and the second surface light source laser section (520), as well as the wavelength of the coaxial vision camera section (530).

[0056] The optical unit (550) includes a plurality of optical systems, including mirrors, filters, and lenses, and uses these plurality of optical systems to coaxially form the focal point of the coaxial vision camera unit (530) with the first and second surface light source laser beams emitted from the first surface light source laser unit (510) and the second surface light source laser unit (520).

[0057] The reflection and transmission processes of the optical section (550) and specific examples will be described later with reference to Figure 4.

[0058] With the above configuration, the first and second surface light source laser beams, which have passed through the first surface light source laser section (510), the second surface light source laser section (520), the optical section (550), and the window section (540) of the laser optical module (500), and the focal point of the coaxial vision camera section (530) are formed on the microball to be repaired.

[0059] For example, the 808 nm wavelength first-plane laser beam for solder ball reflow, emitted from the first-plane laser source section (510), forms a first flat-top region of 100 × 100 μm size.

[0060] This first flat-top region corresponds to the microballs to be repaired, and it ensures uniformity of melting by applying uniform thermal energy to the microballs.

[0061] Furthermore, the 980nm wavelength preheating second-plane light source laser beam emitted from the second-plane light source laser section (520) forms a second flat-top region of 4×4mm size.

[0062] This second flat-top region covers the outer periphery of the microball to be repaired, further improving repair quality by suppressing energy dissipation to the area around the microball during reflow.

[0063] Here, the centers of the first flat-top region and the second flat-top region are formed coaxially, and it will be apparent to those skilled in the art that the wavelength band and the size of the flat-top region in the above-described embodiment can be changed according to the specifications of the PCB and microballs.

[0064] With the above configuration, the laser optical module (500) can achieve stable uniformity and improved processing speed in microball repair.

[0065] Figure 4 shows the detailed configuration and specifications of the optical unit according to an embodiment of the present invention.

[0066] As shown in Figure 4, the optical unit (550) is a specific example illustrating its detailed configuration and specifications.

[0067] The optical section (550) may include a mirror (551), a first WDM (Wavelength Division Multiplexing) filter (552), a focusing lens (553), and a second WDM filter (554).

[0068] The mirror (551) is positioned on one side of the second surface light source laser section (520) and can reflect the second surface light source laser beam in the second wavelength band (e.g., 900-1000 nm). For example, the mirror (551) is positioned to form a 45-degree incident angle with the second surface light source laser beam and reflects the second surface light source laser beam towards the first WDM filter (552).

[0069] The first WDM filter (552) can be a filter with an AOI of 45 degrees and can be placed at the emission section of the first surface light source laser section (510).

[0070] For example, the first WDM filter (552) can transmit light in the first wavelength band (e.g., 600-820 nm) and reflect light in the second wavelength band (e.g., 900-1000 nm).

[0071] In other words, the first WDM filter (552) can transmit the 808 nm wavelength emitted from the first surface light source laser unit (510) and re-reflect the 980 nm wavelength reflected by the mirror (551).

[0072] A focusing lens (553) can be an f100 lens and can be placed between the first WDM filter (552) and the second WDM filter (554).

[0073] For example, the focusing lens (553) can coaxially transmit the 808nm and 980nm wavelength first-plane laser beams and the second-plane laser beams transmitted and reflected by the first WDM filter (552).

[0074] The second WDM filter (554) can be a 45-degree AOI filter and can be positioned to form a 45-degree angle between the focusing lens (553) and the window section (540), i.e., with respect to the lens section of the coaxial vision camera section (530).

[0075] For example, the second WDM filter (554) can transmit light in the first and second wavelength bands (e.g., 600-1000 nm) and reflect light in the third wavelength band (e.g., 400-500 nm).

[0076] In other words, it allows the 808nm and 980nm wavelengths that have passed through the focusing lens (553) to pass through, while reflecting the third wavelength that the coaxial vision camera unit (530) senses.

[0077] On the other hand, the first surface light source laser unit (510) may be equipped with a collimating lens (512) on one side.

[0078] Furthermore, the second surface light source laser unit (520) is equipped with a collimating lens (523) on one side, which can shape a circular laser beam incident on the other side into a rectangular beam.

[0079] The coaxial vision camera unit (530) may further include an IR filter (531) that transmits only the third wavelength (400-500 nm) band. That is, the coaxial vision camera unit (530) receives only light of the third wavelength (400-500 nm) through the IR filter (531).

[0080] The window section (540) may include window glass (541) and ring lighting (542).

[0081] For example, a window pane (541) can be placed in the center of the window section (540), and a ring light (542) composed of blue LEDs or the like can be placed around the window pane (541).

[0082] With this configuration of the optical unit (550), the first-plane light source laser beam, the second-plane light source laser beam, and the light-receiving path of the vision camera unit form a coaxial structure. This enables precise monitoring and reflow processes.

[0083] Figure 5 shows a laser optical module and thermal imaging camera, which are further equipped with a side vision camera according to an embodiment of the present invention.

[0084] As shown in Figure 5, the side vision camera (560) is additionally provided on one side of the laser optical module (500) and is positioned at a predetermined angle (e.g., 30°) to capture images of the side of the microball and the PCB substrate.

[0085] The side vision camera (560) can capture and monitor changes in the size, overall position, reflective properties, and shape of microballs as they melt.

[0086] Furthermore, the side vision camera (560) can monitor the height of microballs, which are difficult to recognize with the coaxial vision camera unit (530), and the filling state at stepped areas of the PCB. In addition, the side vision camera (560) can compensate for the light blurring phenomenon that occurs in the coaxial vision camera unit (530) when flux burns.

[0087] Therefore, the laser optical module (500) provides the laser recipe control unit (700) with multiple images captured by the coaxial vision camera unit (530) and the side vision camera (560), enabling the laser recipe control unit (700) to control the laser output and laser irradiation time based on the image analysis.

[0088] On the other hand, a thermal imaging camera (600) is additionally provided on the other side of the laser optical module (500) and is positioned at a predetermined angle (e.g., 30°) to capture the temperature of the PCB substrate or microballs.

[0089] The thermal imaging camera (600) provides the laser recipe control unit (700) with an image of the temperature of the PCB substrate or microballs, enabling the laser recipe control unit (700) to control the laser power based on the image analysis.

[0090] The side vision camera (560) can observe the size, position, and shape of microballs with high precision in a relatively narrow area. On the other hand, the thermal imaging camera (600) can measure temperature changes over a wide area and can measure temperature changes at specific pixels.

[0091] Therefore, according to the embodiment of the present invention, precise automatic laser recipe control for microball repair can be achieved based on precise image analysis by a side vision camera (560) and temperature change values ​​of a specific region by a thermal imaging camera (600).

[0092] Figure 6 is a block diagram showing the detailed configuration of the laser recipe control unit according to an embodiment of the present invention.

[0093] Figure 7 is a block diagram showing the detailed configuration of the side vision image analysis unit according to an embodiment of the present invention. Figure 8 is a diagram showing images of a microball before and after laser irradiation using the side vision camera and thermal imaging camera according to an embodiment of the present invention.

[0094] As shown in Figure 6, the laser recipe control unit (700) may include a side vision image analysis unit (710), a thermal image analysis unit (720), a microball state analysis unit (730), and a laser recipe determination unit (740).

[0095] The side vision image analysis unit (710) can analyze the side view images of the microballs and PCB substrate captured by the side vision camera (560) over time, including changes in the size of the microballs, changes in the overall position of the microballs, changes in the brightness and size of the microball reflective surface, and changes in the shape of the microballs.

[0096] Referring to Figure 7, the side vision image analysis unit (710) may include a size change analysis unit (711), a position change analysis unit (712), a reflectivity analysis unit (713), and a shape analysis unit (714).

[0097] The size change analysis unit (711) can detect the size change of microballs associated with laser irradiation.

[0098] For example, the size change analysis unit (711) can analyze the melting state of the microballs by detecting the change in the size of the microball image compared to before laser irradiation when a laser is irradiated onto the microballs and the microballs melt due to the melting of the microballs.

[0099] As shown in Figure 7, the side vision camera (560) captures a side view of the microballs (MBs) when they are partially obscured by the PCB substrate and pads (PADs). When the microballs (MBs) melt due to laser irradiation, the size of the microballs (MBs) in the side view also changes (e.g., decreases). Therefore, it is possible to estimate the melting state of the microballs based on the amount of change in their size.

[0100] The position change analysis unit (712) can detect the overall position change of the microballs due to laser irradiation.

[0101] For example, the position change analysis unit (712) can analyze the melting state of the microballs by detecting the change in the position of the microballs in the left-right direction (X-axis) or up-down direction (Z-axis) compared to before laser irradiation when a laser is irradiated onto the microballs and the microballs melt due to the melting of the microballs.

[0102] As shown in Figure 7, the side vision camera (560) captures a side view of the microballs (MBs) with some of them obscured by the PCB substrate and pads (PADs). When the microballs (MBs) melt due to laser irradiation, a change in position occurs in the side view as the microballs (MBs) fill the pad placement area, either horizontally (X-axis) or vertically (Z-axis) from their initial placement position. Therefore, it is possible to estimate the melting state of the microballs (MBs) based on the amount of positional change of the microballs (MBs).

[0103] The reflection characteristics analysis unit (713) can detect changes in brightness and size of the reflective surface of the microballs due to laser irradiation.

[0104] For example, the reflection characteristic analysis unit (713) can detect changes in the brightness and size of the microball's reflective surface compared to before laser irradiation when a laser is irradiated onto the microball, detect changes in position in the front-to-back direction (Y-axis), and analyze the melting state of the microball.

[0105] As shown in Figure 7, the side vision camera (560) captures a side view of the microballs (MBs) in a state where they are partially obscured by the PCB substrate and pads (PADs). When the microballs (MBs) melt due to laser irradiation, a change in position occurs in the front-to-back direction (Y-axis) from the initial placement position as the microballs (MBs) fill the placement area of ​​the pads (PADs) in the side view.

[0106] On the other hand, since the side view image is a two-dimensional image, it is difficult to directly measure the position change in the front-to-back direction (Y-axis) with high precision. Therefore, the reflection characteristic analysis unit (713) calculates the amount of position change in the front-to-back direction (Y-axis) based on the changes in brightness and size of the reflective surface accompanying the position change of the microball (MB) in the front-to-back direction (Y-axis). This makes it possible to estimate the melting state of the microball (MB) from the amount of change in its reflection characteristics.

[0107] Here, the light source that generates reflected light may include at least one of the illumination light source for the side vision camera and the illumination laser light source.

[0108] The shape analysis unit (714) can detect changes in the shape of microballs caused by laser irradiation.

[0109] For example, the shape analysis unit (714) can detect when a laser is irradiated onto a microball, and the shape of the microball changes from spherical to dome-shaped due to melting.

[0110] Referring again to Figure 6, the thermal image analysis unit (720) can detect and analyze temperature images of the PCB substrate or microballs captured by the thermal image camera (600) over time.

[0111] The thermal image analysis unit (720) can acquire the temperature and temperature distribution of a specific pixel region during the process from the thermal image. In laser auto-recipe control, the laser irradiation time can be set by side-view image analysis of the microball, but it is desirable to determine the precise laser irradiation off timing using the thermal image. By combining laser irradiation control using side-view image analysis and laser irradiation off control using thermal image, laser auto-recipe control can be realized without individual settings even for PCB substrates with various patterns and multiple layer structures.

[0112] Referring to Figure 8, the side vision image analysis unit (710) can analyze the size, position, reflection characteristics, and shape of a specific microball before and after laser irradiation, as shown in Figures 8(a) and (b). In addition, the thermal image analysis unit (720) can detect and analyze the temperature change and temperature distribution of a set pixel area, as shown in Figures 8(c) and (d).

[0113] The microball state analysis unit (730) can analyze the state of the microballs in real time based on the detected values ​​of size changes, overall position changes, reflection characteristic changes, and shape changes of the microballs detected by the side vision image analysis unit (710), and the temperature changes and temperature distribution detected by the thermal image analysis unit (720).

[0114] At this point, the state of the microballs can be classified as "melting in progress" or "melting complete" depending on the degree of melting.

[0115] For example, if the size of the microballs analyzed by the side vision image analysis unit (710) decreases to less than a preset value, or if the microballs change beyond a predetermined value in the left-right direction (X-axis) or up-down direction (Z-axis) from the initial placement area of ​​the pad, or if the change in brightness and size of the reflective surface due to the change in the front-back direction (Y-axis) of the microballs exceeds a predetermined value, or if the shape of the microballs changes from spherical to dome-shaped, the degree of melting of the microballs can be determined based on at least one of these changes.

[0116] Furthermore, in thermal image analysis, if the temperature of a specific pixel region during the process exceeds a threshold, the microball state can be determined as a melting completion state, and if the temperature is below the threshold, it can be determined as a melting progress state.

[0117] The laser recipe determination unit (740) can determine the control of the laser output, laser irradiation time, and laser power irradiated onto the microballs based on the state information of the microballs analyzed by the microball state analysis unit (730).

[0118] For example, if the microballs are in the process of melting, the laser recipe determination unit (740) can either continue laser irradiation according to the currently set laser recipe, or control the laser output and laser irradiation time to accelerate the melting process.

[0119] Furthermore, if the microballs are in a melted state, the laser recipe determination unit (740) can control the laser power to turn off and stop laser irradiation to the microballs.

[0120] In this way, the laser recipe control unit (700) can automatically determine a laser recipe (laser output, laser irradiation time, and laser power) suitable for the microball state, based on the images from the side vision camera (560) and the thermal imaging camera (600), according to the changes in the size, position, brightness and size of the reflective surface, and temperature of the microball.

[0121] As a result, the microball repair apparatus according to the embodiment of the present invention can prevent the occurrence of defective microballs and form good microballs by automatically performing laser recipe control according to the state of the microballs, i.e., the degree of melting.

[0122] Figure 9 is a flowchart showing the operation method of a microball repair device according to an embodiment of the present invention.

[0123] In step (S110), the microball repair apparatus loads PCBs for repairing microballs from a PCB loader. The loaded PCBs can be moved to a working stage (200) via a PCB conveyor (100).

[0124] Here, the PCBs transported by the PCB conveyor (100) are placed on the working stage (200), and the microball repair process is performed.

[0125] In step (S120), the microball repair device can detect the repair location on the PCB where the microballs will be repaired. The location of the microballs to be repaired can be determined in advance using image analysis of the microballs formed on the PCB and PCB design data (e.g., Gerber file, ODB++ file, etc.), or it can be determined in real time.

[0126] In step (S130), the microball repair device can attach the solder ball to the repair position.

[0127] Prior to the adhesion of the solder balls, the microball repair device can apply flux to the solder balls to be repaired using a jetting valve via a flux application section (300) located near the working stage (200).

[0128] When the flux is applied to the repair target location, the solder ball nozzle in the solder ball placement section (400) of the microball repair device picks up the solder balls and attaches them to the flux application location.

[0129] In step (S140), the microball repair device can irradiate the repair location to which the solder ball is attached with first and second surface light source laser beams.

[0130] The microball repair apparatus can focus on the microball repair location on the placed PCB by moving the laser optical module (500) in a first direction (e.g., the X-axis) and the working stage (200) in a second direction (e.g., the Y-axis) perpendicular to the first direction, in order to irradiate the repair location with first and second surface source laser beams.

[0131] Here, the microball repair apparatus can form microballs by using a laser optical module (500) to irradiate the attached solder ball with beams from multiple coaxial surface source lasers having different wavelengths and different irradiation areas.

[0132] In step (S150), the microball repair device can analyze the images from the side vision camera (560) while irradiating with the first and second surface light source laser beams.

[0133] The side vision camera (560) is mounted on one side of the laser optical module (500) and positioned at a predetermined angle (e.g., 30°) to capture images of the side of the microballs and the PCB substrate. Such a side vision camera (560) can capture and monitor changes in the size, overall position, reflection characteristics, and shape of the microballs as they melt.

[0134] A detailed method for analyzing the side vision camera images will be described later with reference to Figure 10.

[0135] In step (S160), the microball repair apparatus can analyze the images from the thermal imaging camera (600) while irradiating with the first and second surface light source laser beams.

[0136] A thermal imaging camera (600) is additionally provided on the other side of the laser optical module (500) and is positioned at a predetermined angle (e.g., 30°) to capture the temperature of the PCB substrate or microballs.

[0137] The thermal imaging camera (600) provides the laser recipe control unit (700) with an image of the temperature of the PCB substrate or microball, enabling the laser recipe control unit (700) to control the laser output, laser irradiation time, and laser power based on the image analysis.

[0138] The side vision camera (560) can precisely observe the size, position, and shape of microballs in a relatively narrow area, while the thermal imaging camera (600) can measure temperature changes over a wide area, as well as measure temperature changes at specific pixels.

[0139] Therefore, the microball repair system can perform precise automated laser recipe control for microball repair based on precise image analysis from the side vision camera (560) and temperature change values ​​in specific areas from the thermal imaging camera (600).

[0140] In step (S170), the microball repair device can analyze the microball condition based on the results of the analyzed side vision camera image and thermal imaging camera image.

[0141] Microball state analysis can analyze the state of microballs in real time based on the detected values ​​of size changes, position changes, reflective property changes, and shape changes of microballs detected in the side vision image analysis, and the temperature changes and temperature distribution detected in the thermal image analysis.

[0142] At this time, the state of the microballs can be analyzed as not yet melting, melting in progress, or melting complete, depending on the degree of melting of the microballs.

[0143] In step (S180), the microball repair device can determine the control of the laser output, laser irradiation time, and laser power irradiated onto the microball based on the analyzed state information of the microball.

[0144] A detailed method for determining the laser recipe according to the state of these microballs will be described later with reference to Figure 11.

[0145] Thus, the microball repair device can determine a laser recipe (laser output, laser irradiation time, and laser power) suitable for the microball condition, based on images captured by the side vision camera (560) and the thermal imaging camera (600), according to the changes in the size, position, brightness and size of the reflective surface, and temperature of the microball.

[0146] Figure 10 is a flowchart showing an image analysis method using a side vision camera in a microball repair apparatus according to an embodiment of the present invention.

[0147] In step (S151), the microball repair device can detect the size change of the microballs caused by laser irradiation.

[0148] The change in size of microballs can be analyzed based on the value of the change in the size of the microball image compared to before laser irradiation, when the microballs are irradiated with a laser and melted.

[0149] For example, a side-vision camera (560) captures a side view of a microball in a state where it is partially obscured by the PCB substrate and pads. When the microball melts due to laser irradiation, the size of the microball area in the side view also changes (e.g., decreases). Therefore, it is possible to estimate the melting state of the microball based on the amount of change in its size.

[0150] In step (S152), the microball repair device can detect the change in the position of the microballs due to laser irradiation.

[0151] In other words, the position change analysis unit (712) of the microball repair device can analyze the melting state of the microballs by detecting the change in the position of the microballs in the left-right direction (X-axis) or up-down direction (Z-axis) compared to before laser irradiation when the microballs are irradiated with a laser and the microballs melt.

[0152] For example, a side-vision camera (560) captures a side view of the microballs when they are partially obscured by the PCB substrate and pads. When the microballs melt due to laser irradiation, a change in position occurs in the left-right direction (X-axis) or up-down direction (Z-axis) from the initial placement area as the microballs fill the pad placement area in the side view. Therefore, it is possible to estimate the melting state of the microballs based on the amount of change in their position.

[0153] In step (S153), the microball repair device can detect changes in brightness and size of the microball reflective surface due to laser irradiation.

[0154] For example, the reflective properties analysis unit (713) of the microball repair device can detect changes in the brightness and size of the microball's reflective surface compared to before laser irradiation when a laser is irradiated onto the microball, detect changes in the front-to-back direction (Y-axis), and analyze the melting state of the microball.

[0155] The side vision camera (560) captures a side view of the microballs when they are partially obscured by the PCB substrate and pads. When the microballs melt due to laser irradiation, a change in position occurs in the front-to-back direction (Y-axis) from the initial placement area as the microballs fill the pad placement area in the side view.

[0156] On the other hand, since the side view from the side vision camera is a two-dimensional image, it is difficult to accurately measure the position change in the front-to-back direction (Y-axis). Therefore, the reflection characteristic analysis unit (713) calculates the amount of position change in the front-to-back direction (Y-axis) based on the changes in brightness and size of the reflective surface accompanying the position change of the microball in the front-to-back direction (Y-axis). This makes it possible to estimate the melting state of the microball from the amount of change in the reflection characteristics of the microball.

[0157] In step (S154), the microball repair device can detect changes in the shape of the microballs caused by laser irradiation.

[0158] For example, the shape analysis unit (714) of the microball repair device can detect when a laser is irradiated onto a microball and the shape of the microball changes from spherical to dome-shaped due to melting.

[0159] Thus, the microball repair device can use images captured by a side vision camera (560) to analyze the degree of sufficient melting of the microballs based on changes in size, position, brightness and size of the reflective surface, and shape of the microballs due to laser irradiation, and control the laser recipe (laser power and laser irradiation time).

[0160] Figure 11 is a flowchart showing a detailed method for controlling the laser recipe in a microball repair apparatus according to an embodiment of the present invention.

[0161] In step (S171), the microball repair apparatus can analyze the melting information of the microballs based on the side vision image analysis and the thermal image camera analysis.

[0162] For example, the microball state analysis unit (730) of the microball repair device can analyze the state of the microball in real time based on the detected values ​​of size changes, position changes, reflection characteristic changes, and shape changes of the microball detected in the microball, as well as the temperature changes and temperature distribution detected in the microball.

[0163] The state of the microballs can be classified as either melting in progress or melting complete, depending on the degree of melting.

[0164] For example, the degree of melting of the microballs can be determined based on at least one of the following changes: when the size of the microballs analyzed by the side vision image analysis unit (710) decreases to less than a preset value; when the microballs change beyond a predetermined value in the left-right direction (X-axis) or up-down direction (Z-axis) from the initial placement area of ​​the pad; when the brightness and size changes of the reflective surface due to the positional change of the microballs in the front-back direction (Y-axis) from the initial placement area of ​​the pad exceed a predetermined value; or when the shape of the microballs changes from spherical to dome-shaped.

[0165] Furthermore, in thermal image analysis, if the temperature of a specific pixel region during the process exceeds a threshold, the microball state can be analyzed as a melted state, and if the temperature of the specific pixel region is below the threshold, the microball state can be analyzed as a melting progress state.

[0166] In step (S172), the microball repair device can set the irradiation duration of the laser irradiated onto the microball based on the melting information of the microball.

[0167] For example, if the melting of the microball is not yet underway, the laser recipe determination unit (740) can set the duration of laser irradiation applied to the microball.

[0168] Furthermore, if the melting of the microballs is in progress, the laser recipe determination unit (740) can be set to maintain the currently set laser irradiation duration.

[0169] At this time, the laser recipe determination unit (740) can set not only the laser irradiation duration but also the laser irradiation output according to the degree of melting of the microballs.

[0170] In step (S173), the microball repair device can confirm whether the set laser irradiation duration has ended.

[0171] If the laser irradiation duration ends, in step (S174), the microball repair device can control the laser power to turn off and stop the laser irradiation to the microball.

[0172] On the other hand, if the laser irradiation duration has not yet ended, in step (S175), the microball repair device can check whether or not a laser off-trigger has occurred.

[0173] A laser off-trigger is a signal that indicates the temperature of the PCB substrate or microballs, as captured by the thermal imaging camera (600), has reached a set threshold, and that the melting of the microballs is complete.

[0174] If a laser off-trigger occurs, in step (S174), the microball repair device can control the laser power to turn off and stop laser irradiation to the microball. On the other hand, if no laser off-trigger occurs, the microball repair device can determine that there is still time remaining for laser irradiation, and can return to step (S171) to re-analyze the degree of melting of the microballs and repeat the method to re-determine the laser recipe according to the current state of the microballs.

[0175] The above description of the present invention is illustrative, and a person with ordinary skill in the art will understand that it can be easily modified into other specific forms without altering the technical idea or essential features of the present invention. Therefore, the embodiments described above should be understood to be illustrative and not limiting in all respects. For example, each component described as a single configuration can be implemented in a distributed manner, and similarly, components described as a distributed configuration can be implemented in a combined form.

[0176] The scope of this invention is defined by the claims described below, and all modified or altered forms derived from the meaning and scope of the claims and the concept of equivalents thereof should be interpreted as being included within the scope of this invention. [Explanation of symbols]

[0177] 100 PCB conveyor 200 Working Stages 300 Flux-coated section 400 Solder ball placement section 500 Laser Optical Modules 600 Thermal imaging camera 700 Laser Recipe Control Unit

Claims

1. In a microball repair device that supports laser auto-recipe, A working stage where the PCB is placed and the microball repair process is performed, A solder ball placement unit that picks up solder balls and attaches them to the position where the repair process is performed, A laser optical module that forms microballs by irradiating a surface light source laser beam onto the attached solder ball, It comprises a laser recipe control unit that controls the laser irradiation output and irradiation time, The aforementioned laser optical module is Further including side vision cameras and thermal imaging cameras, The aforementioned laser recipe control unit, A microball repair apparatus that automatically controls the laser recipe using side view images captured by the side vision camera and temperature images captured by the thermal imaging camera.

2. The aforementioned laser recipe control unit, A side vision image analysis unit analyzes, with respect to the side view images of the microballs and the PCB substrate captured by the side vision camera, at least one of the following changes in size, position, reflected light, and shape of the microballs over time: A thermal image analysis unit that analyzes the temperature change of the PCB substrate or the microballs captured by the thermal image camera, A microball state analysis unit analyzes the state of the microballs based on the information analyzed by the side vision image analysis unit and the thermal image analysis unit, The microball repair apparatus according to claim 1, comprising a laser recipe determination unit that determines the laser output, laser irradiation time, and laser power to be irradiated onto the microball based on the state of the microball.

3. The aforementioned side vision image analysis unit is: The microball repair apparatus according to claim 2, further comprising: a position change analysis unit for detecting vertical and horizontal position changes of the microball due to laser irradiation; and a reflection characteristics analysis unit for detecting changes in brightness and size of the reflective surface of the microball due to laser irradiation.

4. The aforementioned side vision image analysis unit is A size change analysis unit for detecting the size change of the microballs due to the laser irradiation, The microball repair apparatus according to claim 3, further comprising a shape analysis unit for detecting changes in the shape of the microballs due to the laser irradiation.

5. The microball repair apparatus according to claim 3, wherein the reflection characteristic analysis unit detects the values ​​of the change in brightness and size of the reflective surface of the microball due to the melting of the microball accompanying the laser irradiation.

6. The microball repair apparatus according to claim 4, wherein the shape analysis unit detects a value indicating that the shape of the microball has changed from spherical to dome-shaped due to the melting of the microball accompanying the laser irradiation.

7. The microball repair apparatus according to claim 3, wherein the laser recipe determination unit determines the output and duration of the laser irradiation according to the melting state of the microballs analyzed by the microball state analysis unit.

8. The laser recipe determination unit, The microball repair apparatus according to claim 7, wherein when the temperature of the PCB substrate or the microball reaches a threshold, a laser off trigger is generated to stop the operation of the laser irradiated onto the microball.

Images