Laser ball mounting method of integrated circuit board and packaging equipment

Abstract

The invention provides a laser ball mounting method and packaging equipment for an integrated circuit board, and the method comprises the steps: carrying out the preheating of a circuit board, so as to enable the temperature data of the circuit board to reach a preset temperature range; adjusting the intensity data of laser energy according to the current temperature data of the circuit board; according to the warping degree of each welding spot of the circuit board, obtaining a dotting distance between a laser unit and each welding spot of the circuit board; and laser ball mounting is completed according to the dotting distance of each welding spot. According to the laser ball mounting method of the integrated circuit board and the packaging equipment provided by the invention, the quality of the solder balls after ball mounting is ensured.

Description

Technical Field

[0001] The present invention relates to the field of packaging, and particularly to a laser ball mounting method and a packaging device for an integrated circuit board. Background Art

[0002] The manufacturing process of System in Package (SiP) refers to integrating multiple integrated circuits or components in one package, which can better achieve higher integration and functional complexity. In the current SiP manufacturing process of circuit boards, the Surface Mount Technology (SMT) is usually used for ball grid array (BGA) mounting.

[0003] During the BGA ball mounting process, due to the large temperature difference between the circuit board and the solder balls, it may cause the solder balls to be unevenly soldered, resulting in cold soldering or void soldering phenomena. It may also cause the solder joints to crack or the connection between the solder balls and the circuit board pads to be lost. Additionally, it may cause the cooling rate of the molten solder balls to be uneven, resulting in different sizes of metal grains, which will affect the mechanical properties and long-term reliability of the solder joints. Therefore, there is room for improvement. Summary of the Invention

[0004] The purpose of the present invention is to provide a laser ball mounting method and a packaging device for an integrated circuit board to ensure the quality of the solder balls after ball mounting.

[0005] To solve the above technical problems, the present invention is realized through the following technical solutions:

[0006] The present invention provides a laser ball mounting method for an integrated circuit board, including:

[0007] Preheating the circuit board to make its temperature data reach a preset temperature range;

[0008] Adjusting the intensity data of the laser energy according to the current temperature data of the circuit board;

[0009] Obtaining the dotting distance between the laser unit and each solder joint of the circuit board according to the warpage degree of each solder joint of the circuit board;

[0010] Completing laser ball mounting according to the dotting distance of each solder joint.

[0011] In an embodiment of the present invention, the preset temperature range is expressed as 90°C to 150°C.

[0012] In an embodiment of the present invention, in the step of preheating the circuit board to make its temperature data reach the preset temperature range, hot air heating or infrared heating is used for preheating.

[0013] In one embodiment of the present invention, the step of adjusting the intensity data of the laser energy according to the current temperature data of the circuit board includes:

[0014] Obtain a correlation data set of the temperature data of the circuit board and the corresponding laser energy data, wherein the correlation data set includes a plurality of temperature data, and each temperature data corresponds to one laser energy data;

[0015] According to the functional relationship between the temperature data and the laser energy data, fit them to obtain a corresponding fitting function;

[0016] Obtain the current temperature data of the circuit board, and input the current temperature data as a parameter into the fitting function to obtain the corresponding current laser energy data;

[0017] Adjust the parameters of the laser unit in the ball placement module according to the current laser energy data.

[0018] In one embodiment of the present invention, the step of adjusting the intensity data of the laser energy according to the current temperature data of the circuit board includes:

[0019] Obtain a correlation data set of the temperature data of the circuit board and the corresponding laser energy data, wherein the correlation data set includes a plurality of temperature data, and each temperature data corresponds to one laser energy data;

[0020] Set a plurality of consecutive temperature range intervals according to the temperature data;

[0021] Obtain the laser energy data corresponding to the temperature data within the temperature range interval, and take the average value of the laser energy data to obtain the corresponding average laser energy data;

[0022] Obtain the temperature range interval in which the current temperature data of the circuit board is located, and obtain the corresponding average laser energy data, denoted as the current laser energy data;

[0023] Adjust the parameters of the laser unit in the ball placement module according to the current laser energy data.

[0024] In one embodiment of the present invention, at least one of the temperature data is distributed within the temperature range interval, and the temperature range interval corresponds to one average laser energy data.

[0025] In one embodiment of the present invention, the step of obtaining the dotting distance between the laser unit and each solder joint of the circuit board according to the warpage degree of each solder joint of the circuit board includes:

[0026] Obtain the overall warpage data of the circuit board;

[0027] Obtain the warpage data of each solder joint according to the overall warpage degree of the circuit board to generate a warpage data set, wherein the warpage data set includes the positions of different solder joints and the corresponding warpage data;

[0028] Obtain the dotting distance between each solder joint and the laser unit of the ball mounting module according to the warpage data set.

[0029] In an embodiment of the present invention, the overall warpage data of the circuit board represents the distance between the highest point and the lowest point of the warpage of the circuit board in the vertical direction.

[0030] In an embodiment of the present invention, the dotting distance represents the distance between each solder joint and the laser unit of the ball mounting module in the vertical direction.

[0031] The present invention also provides a packaging device for an integrated circuit board, including:

[0032] A heating unit for preheating the circuit board so that its temperature data reaches a preset temperature range;

[0033] A laser unit for adjusting the intensity data of the laser energy according to the current temperature data of the circuit board, and the laser unit is also used to obtain the dotting distance between the laser unit and each solder joint of the circuit board according to the warpage degree of each solder joint of the circuit board; and

[0034] A laser unit for completing laser ball mounting according to the dotting distance of each solder joint.

[0035] As described above, the present invention provides a laser ball mounting method and a packaging device for an integrated circuit board. During the ball mounting process, by preheating the circuit board, the warpage and even crack phenomena of the circuit board can be reduced, the wettability of the solder joints can be effectively improved, so as to ensure that the solder joints adhere to the solder balls better. At the same time, the heat loss of the ball mounting module when placing the solder balls on the solder paste can also be reduced, thereby improving the production efficiency. According to the current temperature data of the circuit board, the intensity data of the laser energy output by the laser unit can be self-adjusted, which can prevent the solder balls from being damaged due to excessive laser energy.

[0036] Of course, it is not necessary for any product implementing the present invention to achieve all the above advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0038] Figure 1 It is a flowchart of the packaging method of an integrated circuit board in an embodiment of the present invention;

[0039] Figure 2 is Figure 1 the flowchart of step S10 in

[0040] Figure 3 is Figure 1 the flowchart of step S20 in

[0041] Figure 4 It is a flowchart of the laser ball mounting method of an integrated circuit board in an embodiment of the present invention;

[0042] Figure 5 is Figure 4 the flowchart of step S32 in

[0043] Figure 6 is Figure 4 another flowchart of step S32 in

[0044] Figure 7 is Figure 4 the flowchart of step S33 in

[0045] Figure 8 is Figure 1 the flowchart of step S40 in Specific embodiments

[0046] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0047] Please refer to Figure 1 , the present invention provides a packaging method for an integrated circuit board, which can be applied to the SiP manufacturing process of an integrated circuit board (Printed Circuit Board, PCB) to complete laser ball mounting on the PCB board. The packaging method may include the following steps:

[0048] Step S10: Obtain a circuit board, perform a chip mounting process on the ball mounting surface of the circuit board to solder electronic components on the ball mounting surface;

[0049] Step S20: Perform a chip mounting process on the functional surface of the circuit board to solder electronic components on the functional surface;

[0050] Step S30: Perform laser ball implantation on the pads of the ball-implanting surface of the circuit board to implant solder balls on the solder joints.

[0051] Step S40: Inspect the circuit board to check whether the quality of the circuit board meets the standard.

[0052] Please refer to Figure 2 , in an embodiment of the present invention, when step S10 is executed, specifically, step S10 may include the following steps:

[0053] Step S11: Obtain the circuit board and print solder paste on the ball-implanting surface of the circuit board.

[0054] Step S12: Perform chip mounting on the ball-implanting surface of the circuit board to attach electronic components to the ball-implanting surface.

[0055] Step S13: Perform reflow soldering on the ball-implanting surface of the circuit board to complete the soldering of the electronic components.

[0056] Step S14: Inspect the ball-implanting surface of the circuit board to check whether the quality of the solder joints meets the standard.

[0057] In an embodiment of the present invention, when step S11 is executed, specifically, before printing solder paste on the ball-implanting surface of the circuit board, it is necessary to ensure that the solder paste printing module has completed initialization, and the solder paste should be at the applicable temperature and evenly mixed to ensure its viscosity is suitable for printing. At the same time, a matching stencil template is required. The stencil template has openings corresponding to the pads of the circuit board.

[0058] After that, the circuit board can be fixed on the platform of the solder paste printing module. The platform can be provided with positioning pins or other fixtures to ensure that the holes on the stencil template are precisely aligned with the pads of the circuit board. For example, through an Automated Optical Inspection (AOI) module, the position can be automatically corrected by using the images captured by the imaging unit and the positioning marks on the circuit board.

[0059] After the alignment of the circuit board is completed, an appropriate amount of solder paste can be placed at one end of the stencil, and a squeegee or a rubber squeegee can be used for squeegee printing. During squeegee printing, the squeegee will extrude the solder paste into the holes of the stencil at a constant angle and pressure, and transfer it to the pads of the circuit board through the holes. Among them, the pressure applied by the squeegee must be uniform to ensure that the solder paste can evenly enter the holes of the stencil and be transferred to the pads of the circuit board. The solder paste printing module can measure and adjust the pressure of the squeegee through a sensor. After the solder paste printing is completed, since the separation speed between the stencil and the circuit board also has a great impact on the printing quality, the stencil needs to be carefully separated to ensure that the solder paste remains on the pads of the circuit board. In this embodiment, the stencil can be separated from the circuit board by the solder paste printing module in a way of lifting vertically or lifting the front end first and then the rear end.

[0060] In an embodiment of the present invention, when step S12 is executed, specifically, Surface-Mount Technology (SMT) can be used to assemble electronic components on the circuit board, and the electronic components can be accurately placed on the pads of the circuit board where the solder paste has been printed. Before chip placement, the printed solder paste can be verified to ensure that its shape, volume, and position meet the requirements. For example, the solder paste can be verified through the AOI module. If the shape, volume, and position of the printed solder paste meet the requirements, the next process can be carried out. If any one of the shape, volume, and position of the printed solder paste does not meet the requirements, a mark can be made on the circuit board for subsequent reprinting.

[0061] In this embodiment, a chip placement module can be used for chip placement. The chip placement module can load various electronic components to be placed, including but not limited to chips, resistors, capacitors, and integrated circuits, etc. These electronic components can be stored in the feeder module, and the feeder module can provide electronic components to the chip placement module for assembly according to the program.

[0062] Specifically, before chip placement by the chip placement module, the chip placement module needs to be programmed to set the position, placement angle, and other required parameters of each electronic component. At the same time, the pick-and-place head on the chip placement module is calibrated to ensure that it can accurately pick up electronic components from the feeder and correctly place them on the pads of the circuit board. Among them, the pick-and-place head of the chip placement module can automatically pick up electronic components from the feeder module according to the pre-programmed path and coordinates and accurately place them on the designated pads printed with solder paste. The chip placement module can use a vacuum suction pen to capture and release electronic components.

[0063] After the electronic component is placed on the solder paste, the pick-and-place head needs to adjust the pressure between the electronic component and the pad. The pressure between the two should be appropriate to ensure good contact and not disperse the solder paste. After the electronic component is placed, the AOI module can be used to verify the position of the electronic component to ensure that its position meets the requirements. For example, when verifying the position of the electronic component through the AOI module, if the positions of the electronic components after placement all meet the requirements, the next process can be carried out. If the position of a certain electronic component does not meet the requirements, a mark can be made on this electronic component for subsequent fine-tuning to ensure that its position meets the requirements.

[0064] In an embodiment of the present invention, when performing step S13, specifically, reflow soldering refers to the process of firmly soldering electronic components to a circuit board in the packaging process. In reflow soldering, the solder paste printed on the circuit board is heated to a molten state and then cooled to form solid solder joints. When performing the reflow soldering process, the circuit board after placement can be transferred to the reflow soldering module.

[0065] First, the reflow soldering module can preheat the circuit board. In the preheating stage, to make its temperature reach a certain temperature range, such as 150°C to 180°C. By preheating the circuit board, the flux in the solder paste can be effectively activated, the solvent in it can be removed, and the thermal shock of the electronic components and the circuit board can be prevented.

[0066] After that, the reflow soldering module can control the temperature of the circuit board to be in the constant temperature stage. In the constant temperature stage, the temperature on the circuit board is equalized, so that all parts of the circuit board reach the same temperature as in the preheating stage, continue to remove any residual solvent in the flux and the solder paste, and ensure that the solder paste has a uniform wetting performance.

[0067] Furthermore, the reflow soldering module can control the circuit board to be in the high temperature stage. In the high temperature stage, the temperature in the reflow zone can be controlled to rise above the melting point of the solder paste. At this time, the solder paste melts, and the ends of the electronic components form a physical connection with the pads on the circuit board. The temperature data in the high temperature stage can be between 217°C and 250°C. The specific value of the temperature data in the high temperature stage can depend on the type of solder paste and the requirements of the welding components, which are not limited here. Among them, the temperature data needs to be controlled at an accurate peak for a period of time to ensure the formation of good soldering.

[0068] Finally, the reflow soldering module can control the circuit board to be in the cooling stage. In the cooling stage, the solder joints are quickly cooled below room temperature to avoid the formation of poor solder joints. In the cooling stage, an appropriate cooling rate plays an important role in the strength and quality of the solder joints. In this embodiment, by precisely controlling the temperature conditions in each stage, the soldering work of the electronic components on the circuit board can be completed efficiently and stably.

[0069] In one embodiment of the present invention, when step S14 is executed, specifically, the AOI module refers to a device that uses a vision method to automatically inspect the welding quality of a circuit board according to a preset standard. When using the AOI module to detect the ball grid array (BGA) surface of the circuit board after reflow soldering to check whether the solder joint quality meets the standard, the parameters of the AOI module can be configured first to set appropriate lighting conditions, camera parameters, etc. At the same time, a test software can be preset, and in the test software, the positions of the electronic components to be inspected, the types of electronic components, and the types of defects can be set.

[0070] When detecting the BGA surface of the circuit board, first, the circuit board can be conveyed into the AOI module, and the position can be automatically corrected by using the image captured by the camera unit in the AOI module and the positioning marks on the circuit board. After the position calibration of the circuit board is completed, the camera unit of the AOI module can capture images of the solder joints, electronic components, and other key areas on the circuit board from different angles. Images from different angles are beneficial to improving the accuracy of inspection, especially for those solder joints that are difficult to observe.

[0071] In this embodiment, the collected images can be transmitted to the test software, and the test software can use algorithms to inspect each solder joint and electronic component. By comparing the characteristics such as the shape, size, position, and brightness of the solder joints, it can be determined whether the solder joints meet the preset standards. For example, the test software may identify defects such as open solder joints, short circuits, offsets, insufficient soldering, polarity errors, missing components, and component errors in a certain solder joint. When a defect is detected, the AOI module can record the defect and display the position of the defect point and the corresponding defect type on the display module, and then feedback it to the staff to adjust the process and modify the equipment parameters for re-inspection and repair. The AOI module can collect test data for subsequent quality control and statistical analysis, which helps to continuously improve the production process.

[0072] Please refer to Figure 3 , in one embodiment of the present invention, when step S20 is executed, specifically, step S20 may include the following steps:

[0073] Step S21: Turn over the circuit board to print solder paste on its functional surface;

[0074] Step S22: Perform a surface mounting process on the functional surface of the circuit board to attach the electronic components to the functional surface;

[0075] Step S23: Perform reflow soldering on the functional surface of the circuit board to complete the soldering of the electronic components;

[0076] Step S24: Inspect the functional surface of the circuit board to check whether the solder joint quality meets the standard.

[0077] In an embodiment of the present invention, since the surface mounting on the ball grid surface of the circuit board is completed in the above step S10, then, the circuit board can be turned over to perform surface mounting on the functional surface of the circuit board again. When performing surface mounting on the functional surface of the circuit board, the processing procedure is the same as that of the above surface mounting on the ball grid surface, and will not be elaborated here.

[0078] Please refer to Figure 4 , in an embodiment of the present invention, when step S30 is executed, after the surface mounting on the ball grid surface and the functional surface of the circuit board is completed, ball implantation can be performed on the ball grid surface. In this embodiment, the laser ball implantation method can be used to complete the laser ball implantation on the ball grid surface. The laser ball implantation method may include the following steps:

[0079] Step S31: Preheat the circuit board to make its temperature data reach the preset temperature range;

[0080] Step S32: Adjust the intensity data of the laser energy according to the current temperature data of the circuit board;

[0081] Step S33: Obtain the dotting distance between the laser unit and the solder joints of the circuit board according to the warpage of each solder joint on the ball grid surface;

[0082] Step S34: Complete the laser ball implantation according to the dotting distance of each solder joint.

[0083] In an embodiment of the present invention, when step S31 is executed, after the surface mounting process on the ball grid surface and the functional surface of the circuit board is completed, the circuit board can be transferred to the ball grid array (BGA) module to complete the ball implantation process.

[0084] Specifically, before ball placement on the circuit board, the circuit board can be preheated until its temperature reaches a preset temperature range. Preheating the circuit board can ensure the smooth progress of the ball placement process and the soldering process, and improve the soldering quality. By preheating the circuit board, it can effectively prevent a large temperature gradient from occurring between the circuit board and electronic components due to sudden heating during the subsequent soldering process, which may cause the circuit board or electronic components to warp or even crack due to uneven heating. At the same time, preheating can effectively improve the wettability of the solder joints, thereby ensuring that the solder joints adhere to the solder balls better and can fuse with the pads better during the subsequent soldering stage. Moreover, preheating can effectively reduce the moisture in the circuit board and solder paste, preventing the moisture from being rapidly heated during the soldering process, resulting in false soldering or voids inside the solder joints. Furthermore, preheating can reduce thermal stress, avoid damage or warping of the circuit board caused by rapid temperature changes, and can also optimize the thermal cycle of the ball placement process to obtain better ball placement quality and passing rate. Before the ball placement process, by preheating the temperature of the circuit board to match the temperature of the ball placement process, the heat loss of the ball placement module when placing the solder balls on the solder paste can be reduced, thereby improving production efficiency.

[0085] In an embodiment of the present invention, when preheating the circuit board, the circuit board can be preheated by a heating unit in the ball placement module. The heating unit can preheat the circuit board by means of hot air heating or infrared heating.

[0086] Among them, hot air heating refers to using a hot air gun or a hot air circulation system to evenly blow hot air onto the surface of the circuit board, and the heat is transferred to the circuit board by convection. Hot air heating uses the method of air flow, which is beneficial to quickly and evenly heat the circuit board and perform heat transfer more fully. When performing hot air heating, the temperature and flow rate of the hot air gun or hot air circulation system can be set, and it is ensured that the hot air can evenly cover the surface of the circuit board. At the same time, the preheating time is set so that the temperature of the circuit board slowly rises to the preset temperature. During the preheating process, the temperature of the circuit board needs to be monitored in real time to ensure that it does not exceed the temperature threshold. Among them, the temperature threshold refers to the temperature at which the circuit board undergoes vitrification when it reaches this temperature.

[0087] Infrared heating refers to using an infrared emitter to generate infrared radiation and directly transfer the heat to the circuit board. Infrared heating uses the method of radiation heating, which can penetrate more deeply into the interior of the circuit board to improve the preheating efficiency of the circuit board. When performing infrared heating, the power and radiation range of the infrared emitter can be configured to ensure that the circuit board is within the radiation range of the infrared emitter. At the same time, the preheating time is set so that the temperature of the circuit board slowly rises to the preset temperature. During the preheating process, the temperature of the circuit board needs to be monitored in real time to ensure that it does not exceed the temperature threshold.

[0088] During the preheating process, it is necessary to use a temperature sensor, etc. for real-time temperature monitoring to prevent overheating or uneven heating. At the same time, it is necessary to ensure that the overall and local temperature distributions of the circuit board are uniform to improve the subsequent ball mounting quality. Also, it is necessary to control the temperature rise rate of preheating to prevent an increase in the thermal stress of the circuit board and electronic components. In this embodiment, the preset temperature can be within a preset temperature range, and the preset temperature range can be set to 90°C to 150°C. Of course, the specific numerical value of the preset temperature range can also be set according to actual needs and is not limited here.

[0089] Please refer to Figure 5 , in an embodiment of the present invention, when step S32 is executed, specifically, step S32 may include the following steps:

[0090] Step S3211: Obtain a dataset of the correlation between the temperature data of the circuit board and the corresponding laser energy data. Among them, the correlation dataset may include multiple temperature data, and each temperature data corresponds to a laser energy data;

[0091] Step S3212: Fit according to the functional relationship between the temperature data of the circuit board and the corresponding laser energy data to obtain the corresponding fitting function;

[0092] Step S3213: Obtain the current temperature data of the circuit board, and input the current temperature data as a parameter into the fitting function to obtain the corresponding current laser energy data;

[0093] Step S3214: Adjust the parameters of the laser unit in the ball mounting module according to the current laser energy data.

[0094] In an embodiment of the present invention, when step S3211 is executed, specifically, after preheating the circuit board, it is necessary to start ball mounting on the circuit board. Between the preheating stage and the ball mounting stage, a certain amount of time will pass, which will cause a certain change in the current temperature of the circuit board. For different circuit boards, the temperature after each preheating may also be different. Before the ball mounting stage, the current temperature of each circuit board may not be the same. Therefore, for different circuit boards, it is necessary to correct the laser energy output by the laser unit, so as to ensure that the corrected laser unit can successfully complete the ball mounting process, prevent the circuit board from being damaged due to excessive laser energy output by the laser unit, or prevent the ball mounting from failing due to too small laser energy output.

[0095] Furthermore, during the ball mounting process, since the current temperature data of the circuit board is correlated with the laser energy data output by the laser unit, a correlation data set of the temperature data and the corresponding laser energy data of the circuit board can be obtained in advance through experiments. For example, through experiments, it can be learned that when the temperature data is 25°C, the laser energy data can be in the range of 840 mJ to 997 mJ. When the temperature data is 100°C, the laser energy data can be in the range of 720 mJ to 800 mJ. When the temperature data is 150°C, the laser energy data can be in the range of 620 mJ to 765 mJ.

[0096] In an embodiment of the present invention, when performing step S3212, specifically, after obtaining the correlation data set, the temperature data of the circuit board can be used as the abscissa and the laser energy data as the ordinate to fit all the data to obtain the corresponding fitting function. During the fitting process, methods such as linear fitting, polynomial fitting, exponential fitting, and logarithmic fitting can be used for fitting. In this embodiment, according to the data in the correlation data set, a corresponding scatter plot can be drawn to observe the distribution of the data, so as to initially select a suitable model for fitting. For example, if the data in the scatter plot is similar to a straight line, a linear model can be selected; if it is similar to a parabola, a quadratic polynomial model can be selected. Then, the least squares method or other optimization techniques can be used to evaluate the model parameters according to the selected model. Finally, the obtained fitting function can be verified according to a new set of temperature data and corresponding laser energy data of the circuit board. In other embodiments, fitting can also be performed through computer software to obtain the fitting function, such as Python (using libraries such as NumPy and SciPy or specialized libraries such as statsmodels and scikit-learn), R, MATLAB, etc.

[0097] In an embodiment of the present invention, when performing step S3213 and step S3214, specifically, after obtaining the fitting function, the current temperature data of the circuit board can be obtained according to the temperature sensor and input into the fitting function as a parameter to obtain the corresponding current laser energy data. The current laser energy data obtained at this time is a more appropriate energy, which can successfully complete the ball mounting process of the current circuit board. After that, in order to enable the laser output by the laser unit in the ball mounting module to reach the current laser energy data, the parameters of the laser unit in the ball mounting module need to be adjusted. For example, the output power of the laser can be adjusted by modifying the settings in the ball mounting module or using software, or the focal length of the laser can be changed by adjusting the position of the laser unit head or using a focusing lens to change the size and intensity of the laser spot.

[0098] Please refer to Figure 6, in an embodiment of the present invention, step S32 may also include other steps, for example:

[0099] Step S3221, obtain a correlation data set of the temperature data of the circuit board and the corresponding laser energy data, wherein the correlation data set may include multiple temperature data, and each temperature data corresponds to a laser energy data;

[0100] Step S3222, set multiple consecutive temperature range intervals according to the temperature data of the circuit board, wherein at least one temperature data of the circuit board may be distributed within each temperature range interval;

[0101] Step S3223, obtain the laser energy data corresponding to the temperature data within the temperature range interval, and take the average value of the laser energy data to obtain the corresponding average laser energy data, wherein each temperature range interval may correspond to an average laser energy data;

[0102] Step S3224, obtain the temperature range interval where the current temperature data of the circuit board is located, and obtain the corresponding average laser energy data, denoted as the current laser energy data;

[0103] Step S3225, adjust the parameters of the laser unit in the ball mounting module according to the current laser energy data.

[0104] In an embodiment of the present invention, when performing step S3221, specifically, during the ball mounting process, since the current temperature data of the circuit board is correlated with the laser energy data output by the laser unit, therefore, the correlation data set of the temperature data of the circuit board and the corresponding laser energy data can be obtained in advance through experiments.

[0105] In an embodiment of the present invention, when performing step S3222, specifically, since the number of temperature data may be multiple and the magnitudes of different temperature data may also be different, therefore, multiple consecutive temperature range intervals can be set in advance. For example, multiple consecutive temperature range intervals can be divided into interval A, interval B, interval C, interval D, etc. The temperature x in interval A can be expressed as 10 <= X < 20 °C. The temperature X in interval B can be expressed as 20 <= X < 30 °C. The temperature X in interval C can be expressed as 30 <= X < 40 °C. The temperature X in interval D can be expressed as 40 <= X < 50 °C. And so on until multiple consecutive intervals are obtained. Of course, in other embodiments, the range of each interval can also be 5 °C, 15 °C, etc., and the specific size of the range of the interval can be set according to actual needs, as long as it can satisfy that at least one temperature data of the circuit board is distributed within each temperature range interval.

[0106] In an embodiment of the present invention, when step S3223 is executed, specifically, since at least one temperature data of the circuit board can be distributed in each temperature range interval, and each temperature data of the circuit board can correspond to a laser energy data, therefore, at least one laser energy data can correspond to each temperature range interval. In this embodiment, the average value of the laser energy data corresponding to each temperature range interval can be taken to obtain the corresponding average laser energy data, so that each temperature range interval can correspond to an average laser energy data, which is convenient for adjusting the parameters of the laser unit subsequently.

[0107] In an embodiment of the present invention, when steps S3224 and S3225 are executed, specifically, after the current laser energy data is obtained, the temperature range interval where it is located can be judged, and then the average laser energy data of the temperature range interval where it is located can be obtained, which is denoted as the previous laser energy data. After that, in order to enable the laser output by the laser unit in the ball mounting module to reach the current laser energy data, the parameters of the laser unit in the ball mounting module need to be adjusted.

[0108] Please refer to Figure 7 , in an embodiment of the present invention, when step S33 is executed, specifically, step S33 may include the following steps:

[0109] Step S331: Obtain the overall warpage data of the circuit board;

[0110] Step S332: According to the overall warpage degree, obtain the warpage data of each solder joint to generate a warpage data set, where the warpage data set includes the positions of different solder joints and the corresponding warpage data;

[0111] Step S333: According to the warpage data set, obtain the dotting distance between each solder joint and the laser unit in the vertical direction.

[0112] In an embodiment of the present invention, when step S331 is executed, specifically, before the ball mounting stage, the circuit board will be heated multiple times, which may cause it to have an overall warpage degree (warpage). The overall warpage degree refers to the unevenness of the circuit board caused by thermal stress or other factors. Warpage may have a negative impact on the ball mounting process and the functionality and reliability of the final product. Therefore, it is necessary to measure the warpage degree of the circuit board for subsequent processing. For example, the overall warpage degree of the circuit board can be calculated by the laser unit in the ball mounting module using the laser scanning method. Another example is that the overall warpage degree of the circuit board can also be calculated by the AOI module using the visual detection algorithm.

[0113] When calculating the overall warpage of a circuit board using the laser scanning method, the laser unit can emit a laser beam to irradiate the surface of the circuit board. Subsequently, the laser unit can move along a preset path (horizontal or vertical) to scan the laser beam evenly across the entire surface of the circuit board. The sensor inside the laser unit receives the reflected laser and records the position and reflection time of each scan point, and then the distance between each scan point and the sensor can be calculated. Finally, based on each scan point and the corresponding distance, the highest and lowest points of the circuit board warpage, as well as the distance between the highest and lowest points in the vertical direction, can be determined. This distance can represent the overall warpage of the circuit board.

[0114] When calculating the overall warpage of a circuit board using the vision detection algorithm, the AOI module can use the camera unit to capture images of the circuit board from different angles to capture the complete shape of the warpage. Subsequently, the vision detection algorithm in the AOI module can convert the captured color image into a grayscale image to simplify subsequent processing, and at the same time use various filtering algorithms, such as median filtering, Gaussian filtering, etc. to remove image noise, and apply edge detection algorithms, such as Canny or Sobel algorithms, to identify the contour of the circuit board. If the image is distorted, an image correction algorithm can also be used to correct the perspective distortion. After a series of processing, the features of the circuit board can be extracted. For example, a stereo vision algorithm can be used to reconstruct the three-dimensional surface model of the circuit board first, and then the depth information of each pixel can be calculated through a matching algorithm. Based on the depth information or the stereo vision algorithm, a three-dimensional model of the circuit board surface can be constructed. When the three-dimensional model is obtained, the measured data points of the circuit board can be compared with the expected ideal plane or the reference board data, and the height deviation of the circuit board in different regions can be calculated. By identifying the lowest and highest points, as well as the distance between the highest and lowest points in the vertical direction, this distance can represent the overall warpage of the circuit board.

[0115] In an embodiment of the present invention, when performing step S332 and step S333, specifically, after obtaining the overall warpage of the circuit board, the warpage data of each solder joint on the circuit board can be obtained, and the position of each solder joint can correspond to a warpage data. A warpage data set can be generated according to the warpage data of different solder joints. According to the warpage data set, the ball placement module can adjust the laser unit to ensure that the distance between each solder joint and the laser unit is the same in the vertical direction, and then obtain the corresponding dotting distance, so that after subsequent ball placement, the heights of all solder balls are consistent.

[0116] In an embodiment of the present invention, when step S34 is executed, specifically, for the circuit board of the present application, during the ball mounting process, hundreds or thousands of solder balls need to be mounted on different solder joints at high speed. Therefore, it is necessary to accurately position the solder joints on the circuit board. For example, the circuit board can be positioned first to calibrate the position of the circuit board and the laser unit of the ball mounting module, ensuring that the solder balls are accurately mounted on the predetermined positions, that is, on the solder joints. During the positioning process, the imaging unit of the ball mounting module can scan the marking points on the circuit board to identify the specific position of the circuit board. The imaging unit can calibrate the X-Y coordinate system of the ball mounting module according to the position information of the marking points, ensuring that the laser unit is completely aligned with the predetermined pad positions on the circuit board.

[0117] Further, after calibration, the ball mounting module can send the solder balls to the correct position of the placer through a vibrating disk, and the vibrating disk can ensure that the solder balls move in the correct direction and speed. The laser unit can obtain the solder balls in the placer for the ball mounting process. The laser unit can use vacuum adsorption or other mechanical methods to pick up the solder balls and accurately place them on the pads printed with an appropriate amount of solder paste or solder paste, that is, on the solder joints. In this embodiment, the solder balls can be placed on the corresponding solder joints according to the dotting distances of different solder joints.

[0118] After the solder balls are placed on the solder joints, the laser unit slightly presses the solder balls into the solder paste to ensure that the solder balls can be firmly soldered on the solder joints during the subsequent soldering process. Since hundreds or thousands of solder balls need to be mounted on a circuit board, it is necessary to accurately position the positions of each solder joint. At the same time, the laser unit needs to place the solder balls stably at high speed to improve production efficiency.

[0119] Please refer to Figure 8 , in an embodiment of the present invention, when step S40 is executed, specifically, step S40 may include the following steps:

[0120] Step S41: Detect the solder balls to check whether the solder balls meet the requirements;

[0121] Step S42: Detect the overall coplanarity of the solder balls to check whether the quality of the circuit board meets the standard.

[0122] In an embodiment of the present invention, when step S41 is executed, specifically, when detecting whether the solder balls meet the requirements, the accuracy of the placement of each solder ball, the size and shape of the solder balls, and whether there are defects such as missing balls or multiple balls can be checked through the AOI module. If a certain solder ball has a defect, the AOI module records the position and defect type of the solder ball and saves them in the database. At the same time, it can also be displayed on the display module. If all the solder balls have no defects, the overall coplanarity of the solder balls can be checked. Among them, when a certain solder ball has a defect, the defect position can be repaired subsequently, such as re-supplying balls, etc.

[0123] In one embodiment of the present invention, when step S42 is executed, specifically, when detecting the overall coplanarity of the solder balls, the overall coplanarity of the solder balls can also be detected by the AOI module. If the overall coplanarity does not meet the preset conditions, it indicates that the quality of the circuit board is poor and it is a defective product. If the overall coplanarity meets the preset conditions, it indicates that the quality of the circuit board is good and it is a qualified product.

[0124] In one embodiment of the present invention, the present invention also provides a packaging device for an integrated circuit board. The modules required in the above packaging method can be integrated in the same packaging device. This packaging device can package the circuit board by using the above packaging method and the ball planting method. The packaging device can include modules such as a solder paste printing module, an automatic optical inspection module, a chip mounting module, a feeding module, a reflow soldering module, a display module, and a ball planting module. The functions of the various modules in the packaging device are the same as those of the modules in the above packaging method and the ball planting method, and at the same time, the process flows are also the same, which will not be elaborated here.

[0125] It can be seen that in the above solution, by separating the chip mounting process and the ball planting process, first completing the chip mounting process and then completing the ball planting process, it can effectively prevent the mechanical strength of the solder balls from decreasing due to multiple reflow soldering processes during the manufacturing process. During the ball planting process, by preheating the circuit board, it can reduce the phenomenon of warping or even cracking of the circuit board, effectively improve the wettability of the solder joints, thereby ensuring that the solder joints adhere to the solder balls better, and at the same time, it can also reduce the heat loss when the ball planting module places the solder balls on the solder paste, thereby improving production efficiency. According to the current temperature data of the circuit board, the intensity data of the laser energy output by the laser unit can be self-adjusted, which can prevent the solder balls from being damaged due to excessive laser energy.

[0126] The embodiments of the present invention disclosed above are only used to help explain the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principle and practical application of the present invention, so that those skilled in the relevant technical field can understand and utilize the present invention well. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A method for laser ball placement on an integrated circuit board, characterized in that, Including: Preheating the circuit board to make its temperature data reach a preset temperature range; Adjusting the intensity data of the laser energy according to the current temperature data of the circuit board; Obtaining the dotting distance between the laser unit and each solder joint of the circuit board according to the warpage of each solder joint of the circuit board; Completing laser ball implantation according to the dotting distance of each solder joint.

2. The laser ball mounting method for an integrated circuit board according to claim 1, wherein The preset temperature range is expressed as 90°C to 150°C.

3. The laser ball mounting method for an integrated circuit board according to claim 1, wherein In the step of preheating the circuit board to make its temperature data reach the preset temperature range, hot air heating or infrared heating is used for preheating.

4. The laser ball mounting method for an integrated circuit board according to claim 1, wherein The step of adjusting the intensity data of the laser energy according to the current temperature data of the circuit board includes: Obtaining a correlation data set of the temperature data of the circuit board and the corresponding laser energy data, wherein the correlation data set includes a plurality of temperature data, and each temperature data corresponds to a laser energy data; Fitting according to the functional relationship between the temperature data and the laser energy data to obtain a corresponding fitting function; Obtaining the current temperature data of the circuit board and inputting the current temperature data as a parameter into the fitting function to obtain the corresponding current laser energy data; Adjusting the parameters of the laser unit in the ball implantation module according to the current laser energy data.

5. The laser ball mounting method for an integrated circuit board according to claim 1, wherein The step of adjusting the intensity data of the laser energy according to the current temperature data of the circuit board includes: Obtaining a correlation data set of the temperature data of the circuit board and the corresponding laser energy data, wherein the correlation data set includes a plurality of temperature data, and each temperature data corresponds to a laser energy data; Setting a plurality of consecutive temperature range intervals according to the temperature data; Obtaining the laser energy data corresponding to the temperature data within the temperature range interval and taking the average value of the laser energy data to obtain the corresponding average laser energy data; Obtaining the temperature range interval where the current temperature data of the circuit board is located and obtaining the corresponding average laser energy data, denoted as the current laser energy data; Adjusting the parameters of the laser unit in the ball implantation module according to the current laser energy data.

6. The laser ball mounting method for an integrated circuit board according to claim 5, characterized in that, At least one of the temperature data is distributed within the temperature range interval, and the temperature range interval corresponds to an average laser energy data.

7. The laser ball mounting method for an integrated circuit board according to claim 1, characterized in that, The step of obtaining the dotting distance between the laser unit and each solder joint of the circuit board according to the warpage of each solder joint of the circuit board includes: Obtaining the overall warpage data of the circuit board; Obtaining the warpage data of each solder joint according to the overall warpage to generate a warpage data set, wherein the warpage data set includes the positions of different solder joints and the corresponding warpage data; Obtaining the dotting distance between each solder joint and the laser unit of the ball implantation module according to the warpage data set.

8. The laser ball mounting method for an integrated circuit board according to claim 7, characterized in that, The overall warpage data of the circuit board characterizes the distance between the highest point and the lowest point of the warpage of the circuit board in the vertical direction.

9. The laser ball mounting method for an integrated circuit board according to claim 7, wherein The dotting distance characterizes the distance between each solder joint and the laser unit of the ball implantation module in the vertical direction.

10. An encapsulation device for an integrated circuit board, characterized in that, Including: A heating unit for preheating a circuit board to bring its temperature data within a preset temperature range; A laser unit for adjusting the intensity data of laser energy according to the current temperature data of the circuit board, and the laser unit is further configured to obtain the dotting distances between the laser unit and each solder joint of the circuit board according to the warpage degrees of each solder joint of the circuit board; And A laser unit for completing laser ball implantation according to the dotting distances of each solder joint.

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