A method, apparatus and system for exposing and developing PCB printed circuit boards

Abstract

This invention discloses a method, apparatus, and system for exposing and developing PCB printed circuit boards, relating to the field of printed circuit technology. The method includes: acquiring target light intensity data and target temperature data for each unit area of ​​the PCB to be processed during the exposure process, wherein the target light intensity data includes the substrate surface light intensity and the exposure light intensity; determining process stability parameters for each unit area based on the substrate surface light intensity and target temperature data; determining the cumulative exposure dose for each unit area based on the exposure light intensity at each time point; determining the optimal exposure time for each unit area based on the process stability parameters and cumulative exposure dose; dynamically optimizing the optimal exposure time for each unit area until the exposure termination condition is met; and developing the PCB to be processed. This invention can improve the manufacturing quality of PCB printed circuit boards.

Description

Technical Field

[0001] This invention relates to the field of printed circuit technology, and specifically to a method, apparatus, and system for exposing and developing PCB printed circuit boards. Background Technology

[0002] In the manufacturing system of printed circuit boards (PCBs), the exposure process is a technically intensive and crucial step. Like a precise sculptor, it directly sculpts the circuit patterns on the PCB with millimeter-level precision and superior quality. These minute details are key factors determining the performance of electronic products. For PCB manufacturers, mastering accurate and efficient exposure technology is undoubtedly a core asset for gaining a competitive edge in the fierce market.

[0003] Current exposure technologies mainly rely on linear correlation models between light intensity and exposure time to set exposure time parameters in the exposure process.

[0004] However, the exposure time parameter setting accuracy in this method is low, which can easily lead to overexposure or underexposure, resulting in poor manufacturing quality of PCB printed circuit boards. Summary of the Invention

[0005] This invention provides a method, apparatus, and system for exposing and developing PCB printed circuit boards, which can improve the manufacturing quality of PCB printed circuit boards.

[0006] A first aspect of the present invention provides a method for exposing and developing a PCB printed circuit board, comprising:

[0007] Acquire the target light intensity data and target temperature data of each unit area of ​​the PCB printed circuit board to be processed during the exposure process. The target light intensity data includes the substrate surface light intensity when the light reaches the surface of the unit area and the exposure light intensity of the unit area.

[0008] Based on the light intensity and target temperature data of each substrate surface, the process stability parameters of each unit region are determined. The process stability parameters are used to characterize the stability of the unit region during the exposure process.

[0009] Based on the exposure light intensity of each unit region at each time, the cumulative exposure dose of each unit region is determined respectively.

[0010] Based on the process stability parameters and cumulative exposure dose of each unit region, the optimal exposure time for each unit region is determined.

[0011] The optimal exposure time for each unit area is dynamically optimized until the exposure termination condition is met. Then, the PCB printed circuit board to be processed is developed to obtain the processed target PCB printed circuit board.

[0012] In some possible implementations, process stability parameters for each unit region are determined based on the light intensity and target temperature data of each substrate surface, including:

[0013] Based on the light intensity of the substrate surface in each unit region, the local light intensity attenuation coefficient of each unit region is determined.

[0014] The equivalent exposure dose for each unit region is determined by utilizing the local light intensity attenuation coefficient of each unit region.

[0015] Based on the line distribution information in the target unit area, the line heat accumulation coefficient of the target unit area is determined. The line heat accumulation coefficient is used to characterize the degree of heat accumulation in the target unit area during the exposure process. The target unit area is any unit area.

[0016] Based on the line heat accumulation coefficient, target temperature data, and equivalent exposure dose of each unit region, the process stability parameters of the target unit region are determined.

[0017] In some possible implementations, the local light intensity attenuation coefficient of each unit region is determined based on the light intensity of the substrate surface in each unit region, including:

[0018] The light intensity difference between the light intensity at the light source outlet and the light intensity on the substrate surface of the unit region is obtained.

[0019] By utilizing the light intensity difference and the fixed optical path distance between the light source and the PCB printed circuit board to be processed, the local light intensity attenuation coefficient of the unit area is determined.

[0020] In some possible implementations, the line heat accumulation coefficient of the target unit area is determined based on the line distribution information in the target unit area, including:

[0021] Obtain the number of lines, the number of inflection points, and the line width and length of each line in the target unit area;

[0022] The line area of ​​each line is determined based on its line width and line length.

[0023] The heat accumulation coefficient of the lines in the target unit area is determined by using the number of lines, the number of inflection points, and the line area of ​​each line in the target unit area.

[0024] In some possible implementations, process stability parameters for the target cell region are determined based on the line heat accumulation coefficient, target temperature data, and equivalent exposure dose for each cell region, including:

[0025] Obtain the dose standard deviation between the equivalent exposure doses of each unit region;

[0026] Based on the target temperature data of the target unit region, determine the maximum temperature gradient of the target unit region;

[0027] The process stability parameters of the target unit region are determined by using the standard deviation of the dose, the heat accumulation coefficient of the line, and the maximum temperature gradient.

[0028] In some possible implementations, the cumulative exposure dose of each unit region is determined based on the exposure light intensity of each unit region at each time moment, including:

[0029] The exposure intensity of the unit area at each time point is integrated to obtain the integrated value of the exposure intensity.

[0030] The cumulative exposure dose of a unit area is determined by using the integral value of the exposure light intensity of the unit area and the local light intensity attenuation coefficient.

[0031] In some possible implementations, the optimal exposure time for each unit region is determined based on the process stability parameters and the cumulative exposure dose of each unit region, including:

[0032] Based on the process stability parameters and cumulative exposure dose of the unit region, an objective function corresponding to the exposure time of the unit region is constructed.

[0033] The optimal exposure time for a cell region is determined by using an objective function corresponding to the exposure time of that cell region.

[0034] In some possible implementations, the optimal exposure time for each unit region is dynamically optimized until the exposure termination condition is met, at which point the PCB to be processed is developed to obtain the processed target PCB, including:

[0035] Based on the optimal exposure time of each unit region, the PCB printed circuit to be processed is exposed to obtain the candidate PCB printed circuit.

[0036] Based on the candidate PCB printed circuit, determine whether the exposure termination condition is met;

[0037] If the exposure termination condition is not met, the optimal exposure time for each unit area is dynamically optimized, and the process is returned to perform exposure processing on the PCB printed circuit to be processed based on the optimal exposure time for each unit area.

[0038] Under the condition that the exposure termination condition is met, the candidate PCB printed circuit is developed to obtain the processed target PCB printed circuit board.

[0039] A second aspect of the present invention provides a PCB printed circuit board exposure and development apparatus, comprising:

[0040] The data acquisition module is used to acquire the target light intensity data and target temperature data of each unit area of ​​the PCB printed circuit board to be processed during the exposure process. The target light intensity data includes the substrate surface light intensity when the light reaches the surface of the unit area and the exposure light intensity of the unit area.

[0041] The data analysis module is used to determine the process stability parameters of each unit region based on the light intensity and target temperature data of each substrate surface. The process stability parameters are used to characterize the stability of the unit region during the exposure process.

[0042] The data analysis module is also used to determine the cumulative exposure dose of each unit area based on the exposure light intensity of each unit area at each time.

[0043] The time determination module is used to determine the optimal exposure time for each unit region based on the process stability parameters and the cumulative exposure dose of each unit region.

[0044] The circuit board processing module is used to dynamically optimize the optimal exposure time of each unit area until the exposure termination condition is met, and then perform development processing on the PCB printed circuit board to be processed to obtain the processed target PCB printed circuit board.

[0045] A third aspect of the present invention provides a PCB printed circuit board exposure and development system, including a light intensity sensor, a thermal sensor, and a processor:

[0046] A light intensity sensor is used to collect target light intensity data of each unit area of ​​the PCB printed circuit board to be processed during the exposure process.

[0047] Thermal sensors are used to collect target temperature data of each unit area of ​​the PCB printed circuit board to be processed during the exposure process;

[0048] A processor for executing the PCB printed circuit board exposure and development method provided in any of the above aspects.

[0049] In the PCB printed circuit board exposure and development method provided in this invention, based on the target light intensity data and target temperature data of each unit area of ​​the PCB to be processed during the exposure process, the process stability parameters and cumulative exposure dose of each unit area during the exposure process are analyzed. Based on the process stability parameters and cumulative exposure dose of each unit area, the optimal exposure time for each unit area is determined. Finally, the optimal exposure time of each unit area is dynamically optimized in real time until the exposure termination condition is met, at which point the PCB to be processed is developed to obtain the processed target PCB printed circuit board. Thus, this invention dynamically adjusts the optimal exposure time of each unit area of ​​the PCB to be processed based on the target light intensity data and target temperature data during the exposure process until the exposure termination condition is met. This avoids the impact of overexposure or underexposure on the development process and improves the manufacturing quality of the PCB printed circuit board. Attached Figure Description

[0050] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a schematic flowchart of a PCB printed circuit board exposure and development method provided in one embodiment of the present invention;

[0052] Figure 2 A printing process flow diagram of a PCB printed circuit board provided in one embodiment of the present invention;

[0053] Figure 3 This is a schematic flowchart of S102 provided in one embodiment of the present invention;

[0054] Figure 4 This is a schematic diagram of an inflection point provided in one embodiment of the present invention;

[0055] Figure 5 This is a schematic diagram showing the results of a PCB printed circuit board exposure and development apparatus provided in one embodiment of the present invention. Detailed Implementation

[0056] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a PCB printed circuit board exposure and development method, apparatus, and system proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0058] It should be noted that the acquisition, storage, use, and processing of data in the technical solution of this invention all comply with the relevant provisions of laws and regulations.

[0059] It should be noted that in the embodiments of the present invention, certain software, components, models and other existing solutions in the industry may be mentioned. These should be regarded as exemplary and are only intended to illustrate the feasibility of implementing the technical solution of the present invention. However, they do not mean that the applicant has used or necessarily used the solution.

[0060] In the manufacturing process of printed circuit boards (PCBs), the exposure process is a highly technical and crucial step. It's like a master micro-sculptor, using exceptional precision and quality to carve intricate circuit patterns onto the PCB with millimeter-level detail. These seemingly insignificant details are precisely the core elements determining the performance of electronic products. For PCB manufacturers, mastering precise and efficient exposure technology is undoubtedly a key weapon to stand out in fierce market competition.

[0061] Currently, in practical applications of exposure technology, the exposure time parameters in the exposure process are mainly determined based on a linear relationship model between light intensity and exposure time. However, this traditional method has a significant drawback: the accuracy of the set exposure time parameters is poor. This can easily lead to overexposure or underexposure, negatively impacting the manufacturing quality of PCB printed circuit boards and resulting in inconsistent product quality.

[0062] The purpose of this invention is to provide a method, apparatus, and system for exposing and developing PCB printed circuit boards. In the PCB printed circuit board exposure and development method provided by this invention, based on the target light intensity data and target temperature data of each unit area of ​​the PCB to be processed during the exposure process, the process stability parameters and cumulative exposure dose of each unit area during the exposure process are analyzed. Based on the process stability parameters and cumulative exposure dose of each unit area, the optimal exposure time for each unit area is determined. Finally, the optimal exposure time of each unit area is dynamically optimized in real time until the exposure termination condition is met, at which point the PCB to be processed is developed to obtain the processed target PCB printed circuit board. Thus, this invention dynamically adjusts the optimal exposure time of each unit area of ​​the PCB to be processed based on the target light intensity data and target temperature data of the PCB to be processed during the exposure process until the exposure termination condition is met. This avoids the impact of excessive or insufficient exposure time on the development process and improves the manufacturing quality of the PCB printed circuit board.

[0063] The following describes a specific embodiment of a PCB printed circuit board exposure and development method, apparatus and system provided by the present invention.

[0064] Figure 1 A flowchart of a PCB printed circuit board exposure and development method is provided. This PCB printed circuit board exposure and development method can be applied to a server. The PCB printed circuit board exposure and development method may include the following steps S101 to S105.

[0065] S101, acquire the target light intensity data and target temperature data of each unit area of ​​the PCB printed circuit board to be processed during the exposure process. The target light intensity data includes the substrate surface light intensity when the light reaches the surface of the unit area and the exposure light intensity of the unit area.

[0066] In this embodiment, the PCB printed circuit board to be processed can be divided into multiple unit areas according to a set division method. For example, the area of ​​each unit area can be set to 5 cm². 2 .

[0067] Substrate surface light intensity is used to characterize the light intensity that appears on the substrate surface when light propagates to the surface of a cell area on a PCB (Printed Circuit Board). It reflects the energy intensity of the light after passing through various optical elements (such as light sources, lenses, etc.) and the environmental medium before reaching the cell area.

[0068] Exposure light intensity refers to the light intensity that actually acts on the photoresist in a unit area, triggering a chemical reaction in the photoresist and thus achieving the exposure effect. It comprehensively considers factors such as light reflection, absorption, and scattering on the substrate surface, and is the portion of the light intensity that truly affects the photoresist.

[0069] As an example, high-precision light intensity sensors can be installed on a PCB (Printed Circuit Board) at locations that cover various cell areas of the PCB. During exposure, the light intensity sensors measure in real time the light intensity on the substrate surface when light reaches the cell area and the exposure light intensity of the cell area. To ensure measurement accuracy, the light intensity sensors need to be calibrated periodically to eliminate measurement errors caused by environmental factors (such as dust and temperature changes affecting the sensor's performance).

[0070] Meanwhile, multiple thermal sensors are arranged on the PCB printed circuit board, and these sensors should be evenly distributed across each unit area. Temperature sensors can be thermocouples or thermistors, capable of measuring the temperature of the unit area in real time and accurately.

[0071] Furthermore, during data acquisition, the difference in sampling frequency between different sensors results in different numbers of data points in the data sequences obtained by different sensors, making it difficult to align the timestamps of the data points during subsequent analysis. Therefore, this invention further selects to perform timestamp alignment processing on the data sequences acquired by different sensors to facilitate subsequent analysis. In addition, electromagnetic interference and other factors during the acquisition process may cause noise in the data acquired by the sensors, so data preprocessing is also required.

[0072] The specific process may include: First, the server implements cross-sensor clock synchronization based on the IEEE 1588 Precision Time Protocol; the data from high-speed sensors is processed by sliding window averaging downsampling to match the timing of low-speed sensors. Then, the server filters the data sequence using a Gaussian filter to perform data cleaning on the collected data.

[0073] S102, based on the light intensity and target temperature data of each substrate surface, determine the process stability parameters of each unit region. The process stability parameters are used to characterize the stability of the unit region during the exposure process.

[0074] In this embodiment, the process stability parameter is a comprehensive index used to characterize the stability of a unit region during the exposure process.

[0075] As an example, the server performs correlation analysis on the collected data of light intensity and target temperature on the substrate surface. For instance, it studies the trends of light intensity and temperature changes over time, and the mutual influence between them. Statistical analysis methods, such as correlation analysis, can be used to determine the degree of correlation between light intensity and temperature.

[0076] Then, based on the results of the correlation analysis, the calculation formulas for the process stability parameters are defined. For example, the influence of light intensity fluctuation range and temperature fluctuation range on the stability of the exposure process can be considered, and the process stability parameter can be defined as the weighted sum of the light intensity fluctuation coefficient and the temperature fluctuation coefficient. The light intensity fluctuation coefficient can be obtained by calculating the ratio of the standard deviation to the average value of the light intensity on the substrate surface over a certain period of time; the temperature fluctuation coefficient is obtained by calculating the ratio of the standard deviation to the average value of the target temperature over a certain period of time. The weighting coefficients can be determined based on practical experience and experimental data to reflect the relative importance of light intensity and temperature to the stability of the exposure process.

[0077] S103 determines the cumulative exposure dose of each unit region based on the exposure light intensity of each unit region at each time.

[0078] In this embodiment, the cumulative exposure dose refers to the total amount of light radiation energy received by the unit area during the exposure process. It reflects the cumulative effect of light irradiation on the unit area throughout the entire exposure time.

[0079] As an example, during the exposure process, the server continuously records the exposure intensity data of each unit area at various times. The recording frequency can be set according to the actual situation, such as recording once per second, to ensure accurate capture of dynamic changes in exposure intensity.

[0080] Then, the cumulative exposure dose is calculated: for each unit area, the exposure intensity at each moment is multiplied by the corresponding exposure time interval, and then these products are accumulated to obtain the cumulative exposure dose for each unit area.

[0081] S104, based on the process stability parameters of each unit region and the cumulative exposure dose of each unit region, determines the optimal exposure time for each unit region.

[0082] In this embodiment, the server constructs a mathematical model to describe the relationship between process stability parameters, cumulative exposure dose, and exposure effects (such as the resolution of the circuit pattern, linewidth uniformity, etc.). Machine learning algorithms, such as neural networks, can be used to establish a mapping relationship between inputs (process stability parameters and cumulative exposure dose) and outputs (exposure effect evaluation indicators) by learning from a large amount of experimental data.

[0083] Then, based on the established mathematical model, the optimal exposure time for each unit region is solved with the goal of achieving the best exposure effect. For example, the evaluation index of the exposure effect is set as the resolution of the line pattern reaching a predetermined value and the line width uniformity being the best. Under the constraints of process stability parameters and cumulative exposure dose, optimization algorithms (such as genetic algorithms, particle swarm optimization, etc.) are used to search for the exposure time that achieves the optimal exposure effect.

[0084] S105 dynamically optimizes the optimal exposure time for each unit area until the exposure termination condition is met, then performs development processing on the PCB printed circuit board to be processed to obtain the processed target PCB printed circuit board.

[0085] In this embodiment, as Figure 2 The diagram illustrates a printing process flow chart for a PCB (Printed Circuit Board). The PCB printing process includes resist application, pre-baking, exposure, development, etching, and photoresist stripping. Once the exposure termination conditions are met, the exposure process is considered complete, and the development process can then proceed.

[0086] As an example, during the exposure process, the server monitors the exposure status of each unit area in real time, such as the deviation between the actual cumulative exposure dose and the expected value, and changes in process stability parameters. Based on the monitoring results, a feedback control algorithm is used to dynamically adjust the optimal exposure time. For example, if the actual cumulative exposure dose of a certain unit area is lower than the expected value, and the process stability parameters indicate that the exposure process in that area is relatively stable, the optimal exposure time for that unit area can be appropriately extended.

[0087] Simultaneously, exposure termination conditions are set, such as the cumulative exposure dose of all unit areas reaching a predetermined range and the process stability parameters being within acceptable ranges. When these conditions are met, the exposure process is stopped.

[0088] Finally, the exposed PCB is placed in a developing solution and developed according to predetermined development parameters (such as development temperature, development time, and developer concentration). After development, subsequent processes such as etching and photoresist stripping are performed to obtain the processed target PCB.

[0089] As an optional embodiment, such as Figure 3 As shown, S102 may specifically include the following S301 to S304:

[0090] S301, Based on the light intensity of the substrate surface in each unit region, determine the local light intensity attenuation coefficient of each unit region;

[0091] S302, using the local light intensity attenuation coefficient of each unit area, determines the equivalent exposure dose of each unit area;

[0092] S303, Based on the line distribution information in the target unit area, determine the line heat accumulation coefficient of the target unit area. The line heat accumulation coefficient is used to characterize the degree of heat accumulation in the target unit area during the exposure process. The target unit area is any unit area.

[0093] S304 determines the process stability parameters of the target unit area based on the line heat accumulation coefficient, target temperature data, and equivalent exposure dose of each unit area.

[0094] In this embodiment, the local light intensity attenuation coefficient is a physical quantity used to describe the degree of light intensity attenuation during the propagation of light from the light source to the substrate surface of the unit region. It takes into account the effects of absorption, scattering, and dielectric inhomogeneity of optical elements on light intensity.

[0095] Equivalent exposure dose takes into account both the actual light intensity and exposure time acting on the photoresist in the unit area, and is used to measure the light radiation energy received by the unit area during exposure. It plays a crucial role in the degree of chemical reaction of the photoresist, and thus affects the formation quality of PCB circuit patterns.

[0096] The line heat accumulation coefficient is a physical quantity used to characterize the degree of heat accumulation in a target unit area during exposure. It is closely related to the distribution of lines within the unit area (such as line width, spacing, wiring density, etc.). Different line distributions will lead to different thermal effects of the current, resulting in different degrees of heat accumulation.

[0097] As an example, the server analyzes various attenuation factors during light propagation, such as the absorption coefficient and scattering coefficient of optical elements, and the refractive index of the medium. Based on these factors, a mathematical model of light intensity attenuation is established. Then, the collected light intensity data from the substrate surface is substituted into the attenuation model, and the local light intensity attenuation coefficient of each unit region is calculated by fitting or solving the equations.

[0098] Then, the equivalent exposure dose for each unit region is calculated using the following formula 1:

[0099]

[0100] In Formula 1, D ′ (x,y) represents the equivalent exposure dose of the unit region located at (x,y), and α(x,y) represents the local light intensity attenuation coefficient of the unit region located at (x,y). I(x,y,t) represents the exposure light intensity of the unit region located at (x,y) at time t. ′ Used to characterize the preset exposure time, This is used to perform integral calculations to characterize the exposure light intensity of the unit region located at (x,y) at various times within a preset exposure time.

[0101] Then, the server obtains information on the circuit distribution in the target unit area, such as the width, spacing, length, and wiring density, from the PCB design files. Based on the principles of electromagnetism and thermodynamics, and considering factors such as circuit resistance and current density, a mathematical model for heat accumulation in the circuits is established. The circuit distribution information of the target unit area is then substituted into the heat accumulation model to calculate the heat accumulation coefficient.

[0102] Finally, the server integrates the line heat accumulation coefficient, target temperature data, and equivalent exposure dose for each unit area to form a dataset containing multiple influencing factors. By analyzing the impact of the line heat accumulation coefficient, target temperature data, and equivalent exposure dose on the stability of the exposure process, a comprehensive process stability model is established. This process stability model can be an empirical model based on experimental data or a mathematical model obtained through theoretical analysis. For example, a multiple linear regression model or a neural network model can be used to establish the relationship between process stability parameters and various influencing factors. The integrated data is then substituted into the process stability model, and the process stability parameters for the target unit area are calculated through the process stability model.

[0103] This embodiment accurately calculates the local light intensity attenuation coefficient and equivalent exposure dose for each unit area, enabling more precise control of the exposure level in each unit area and avoiding underexposure or overexposure caused by uneven light intensity. Simultaneously, by considering the heat accumulation coefficient and temperature data, exposure parameters can be adjusted in a timely manner, reducing defects such as line deformation and short circuits caused by heat accumulation and temperature changes. Therefore, based on the process stability parameters of each unit area, the line resolution and linewidth uniformity of the PCB printed circuit board can be improved, enhancing product quality.

[0104] As an optional embodiment, S301 may specifically include:

[0105] The light intensity difference between the light intensity at the light source outlet and the light intensity on the substrate surface of the unit region is obtained.

[0106] By utilizing the light intensity difference and the fixed optical path distance between the light source and the PCB printed circuit board to be processed, the local light intensity attenuation coefficient of the unit area is determined.

[0107] In this embodiment, the local light intensity attenuation coefficient of the unit region can be determined by the following formula 2:

[0108]

[0109] In Formula 2, α(x,y) is used to characterize the local light intensity attenuation coefficient of the unit region located at (x,y), I ′ (x,y) represents the light intensity on the substrate surface of the unit region located at (x,y). I0 represents the light intensity at the light source exit, measured by the photodiode integrated into the light source. d represents the fixed optical path distance between the light source and the PCB printed circuit board to be processed; it is a preset mechanical parameter of the exposure equipment and its value is not 0.

[0110] Specifically, the greater the light source intensity attenuation in the unit region at the corresponding coordinate position, the greater the change in light intensity from the light source outlet to the substrate surface at the corresponding position; that is, I0-I ′ The larger the value of (x,y), the larger the corresponding local light intensity attenuation coefficient α(x,y), and the more the light intensity needs to be increased when the exposure device exposes the unit area at that coordinate position.

[0111] This embodiment accurately calculates the local light intensity attenuation coefficient of a unit area based on the light intensity difference between the light intensity at the light source outlet and the light intensity on the substrate surface of the unit area, as well as the fixed optical path distance between the light source and the PCB printed circuit board to be processed. This allows for more precise control of the exposure level of the unit area, improving the manufacturing quality of the PCB printed circuit board.

[0112] As an optional embodiment, S303 may specifically include:

[0113] Obtain the number of lines, the number of inflection points, and the line width and length of each line in the target unit area;

[0114] The line area of ​​each line is determined based on its line width and line length.

[0115] The heat accumulation coefficient of the lines in the target unit area is determined by using the number of lines, the number of inflection points, and the line area of ​​each line in the target unit area.

[0116] In this embodiment, as Figure 4 As shown, a schematic diagram of an inflection point is provided. The inflection point is the corner point where the direction of a line in a PCB (printed circuit board) changes.

[0117] As an example, the heat accumulation coefficient of the target unit area can be determined using the following formula 3:

[0118]

[0119] In Formula 3, LT(x,y) characterizes the line heat accumulation coefficient of the unit region located at (x,y), α(x,y) characterizes the local light intensity attenuation coefficient of the unit region located at (x,y), and r(x,y) characterizes the number of inflection points in the unit region located at (x,y). w characterizes the linewidth, l characterizes the line length, and (w×l) (x,y),i The area of ​​the i-th line in the unit region located at (x,y) is used to characterize the line area, n is used to characterize the number of lines in the unit region located at (x,y), S is used to characterize the area of ​​the unit region and its value is not 0, and e represents the natural constant.

[0120] in, The density factor is used to characterize the unit region located at (x,y). The larger the value, the more heat is generated in the corresponding local region, and the more heat is accumulated, that is, LT(x,y) will become larger. This value is used to characterize the area occupied by the line within the cell region located at (x,y). The larger the value, the more light is received in the cell region, and the more heat accumulates in the corresponding cell region.

[0121] This embodiment accurately calculates the heat accumulation coefficient of the target unit area based on the number of lines, the number of inflection points, and the area of ​​each line. By considering the heat accumulation coefficient and temperature data, exposure parameters can be adjusted in a timely manner to reduce defects such as line deformation and short circuits caused by heat accumulation and temperature changes, thereby improving the manufacturing quality of PCB printed circuit boards.

[0122] As an optional embodiment, S304 may specifically include:

[0123] Obtain the dose standard deviation between the equivalent exposure doses of each unit region;

[0124] Based on the target temperature data of the target unit region, determine the maximum temperature gradient of the target unit region;

[0125] The process stability parameters of the target unit region are determined by using the standard deviation of the dose, the heat accumulation coefficient of the line, and the maximum temperature gradient.

[0126] In this embodiment, the process stability parameters of the target cell region can be specifically determined using the following formula 4:

[0127]

[0128] In Formula 4, P(x,y) is used to characterize the process stability parameter of the unit region located at (x,y), and σ(D ′) is used to characterize the dose standard deviation between the equivalent exposure doses of each unit region, Dt is used to characterize the target dose corresponding to the preset exposure time, and LT(x,y) is used to characterize the line heat accumulation coefficient of the unit region located at (x,y). The maximum temperature gradient value of the cell region located at (x,y) is obtained by performing gradient calculation on the target temperature data of the cell region located at (x,y) and then extracting the maximum value.

[0129] in, This reflects the non-uniformity of light intensity distribution at different locations within the exposure equipment. The more non-uniform the distribution of exposure dose within the exposure equipment, the more... The larger the value; This reflects the maximum temperature difference in a local area on the surface of a PCB. When the exposure time is relatively long, different degrees of heat accumulation will occur at different locations on the PCB surface, resulting in a large heat gradient. At the same time, when heat accumulation occurs, the layout of the circuit in the local area will further affect the heat accumulation process, causing the circuit heat accumulation coefficient LT(x,y) to increase further.

[0130] This embodiment utilizes the dose standard deviation, line heat accumulation coefficient, and maximum temperature gradient to accurately determine the process stability parameters of a unit region. This helps in subsequently determining the optimal exposure time for the unit region based on the process stability parameters, thereby improving the manufacturing quality of PCB printed circuit boards.

[0131] As an optional embodiment, S103 may specifically include:

[0132] The exposure intensity of the unit area at each time point is integrated to obtain the integrated value of the exposure intensity.

[0133] The cumulative exposure dose of a unit area is determined by using the integral value of the exposure light intensity of the unit area and the local light intensity attenuation coefficient.

[0134] In this embodiment, the cumulative exposure dose of the unit area can be determined using the following formula 5:

[0135]

[0136] In Formula 5, D(x,y,T) characterizes the cumulative exposure dose of the unit region located at (x,y) at time T, α(x,y) characterizes the local light intensity attenuation coefficient of the unit region located at (x,y), and I(x,y,τ) characterizes the exposure light intensity of the unit region located at (x,y) at time τ. The integral is used to characterize the exposure light intensity of the unit region located at (x,y) at various times before time T.

[0137] This embodiment utilizes the integral value of the exposure light intensity of a unit area and the local light intensity attenuation coefficient to accurately determine the cumulative exposure dose of the unit area. This helps in subsequently determining the optimal exposure time for the unit area based on the cumulative exposure dose, thereby improving the manufacturing quality of PCB printed circuit boards.

[0138] As an optional embodiment, S104 may specifically include:

[0139] Based on the process stability parameters and cumulative exposure dose of the unit region, an objective function corresponding to the exposure time of the unit region is constructed.

[0140] The optimal exposure time for a cell region is determined by using an objective function corresponding to the exposure time of that cell region.

[0141] In this embodiment, the objective function corresponding to the exposure time of the unit region can be specifically determined by the following formula 6:

[0142]

[0143] In Formula 6, Time(x,y) is used to characterize the optimal exposure time of the cell region located at (x,y), D(x,y,T) is used to characterize the cumulative exposure dose of the cell region located at (x,y) at time T, and DT is used to characterize the target dose corresponding to the exposure duration continuing until time T. T P(x,y) is used to characterize the temperature entropy of the PCB printed circuit board surface at time T, and P(x,y) is used to characterize the process stability parameter of the cell region located at (x,y). e represents the natural constant.

[0144] min T(x,y) {} is used to denote the selection of the minimum value from the calculation results corresponding to each time point in the cell region located at (x,y). T(x,y) {[D(x,y,T)-DT] 2 +En T This means selecting the minimum cumulative value among the squared differences between the cumulative exposure dose and the corresponding target dose, and the corresponding temperature entropy, at various times within the cell region located at (x,y).

[0145] The process stability parameter (P) is used as the exponential weight term e. -P When process stability decreases (manifested as an increase in the standard deviation of dose distribution or an increase in temperature gradient), the exponential term e -PThis significantly amplifies the objective function value, forcing the optimization algorithm to prioritize suppressing stability risks. For example, it can automatically extend the exposure time interval in high temperature gradient regions or shorten the thermal accumulation cycle by reducing the total exposure time. Once stability deterioration (P-value increase) is detected, an exponentially enhanced stability penalty is triggered, suppressing potential defects in advance through a nonlinear response mechanism. In addition, by quantifying the temperature entropy under the temperature field, the temperature distribution on the PCB printed circuit board surface is reflected. When the temperature distribution is uneven, there may be insufficient photoresist decomposition on the PCB printed circuit board surface, resulting in residual photoresist. In this case, the exposure time needs to be appropriately increased, which means that the corresponding temperature entropy will increase, thereby increasing the value of Time(x,y).

[0146] This embodiment accurately determines the optimal exposure time for a unit region based on its process stability parameters and cumulative exposure dose. This avoids the negative impact of overexposure or underexposure on the development process, thereby improving the manufacturing quality of PCB printed circuit boards.

[0147] As an optional embodiment, S105 may specifically include:

[0148] Based on the optimal exposure time of each unit region, the PCB printed circuit to be processed is exposed to obtain the candidate PCB printed circuit.

[0149] Based on the candidate PCB printed circuit, determine whether the exposure termination condition is met;

[0150] If the exposure termination condition is not met, the optimal exposure time for each unit area is dynamically optimized, and the process is returned to perform exposure processing on the PCB printed circuit to be processed based on the optimal exposure time for each unit area.

[0151] Under the condition that the exposure termination condition is met, the candidate PCB printed circuit is developed to obtain the processed target PCB printed circuit board.

[0152] In this embodiment, the server places the PCB to be processed in an exposure device and sets the device parameters according to the optimal exposure time for each unit area. The exposure device typically employs photolithography, using a light source (such as ultraviolet light) to irradiate the photoresist on the PCB surface, causing a chemical reaction that forms the desired circuit pattern. The exposure device is then activated, and each unit area is exposed according to the set optimal exposure time. During exposure, it is necessary to ensure the stability and uniformity of the light source and the accurate positioning of the PCB to guarantee exposure quality. After exposure, a candidate PCB is obtained after preliminary exposure. At this point, a potential circuit pattern has formed on the photoresist, but further processing is required for it to become visible.

[0153] Then, the server pre-sets a series of exposure termination conditions, which can be determined based on the PCB design requirements, manufacturing process standards, and quality inspection indicators. For example, the exposure termination condition could be: if more than 95% of the cell area reaches a preset range of cumulative exposure dose at time T, then the exposure termination condition is satisfied at time T; or if the temperature at any location exceeds T... max Termination is triggered when the temperature reaches 85°C or the dose exceeds the limit for 200 ms.

[0154] Then, professional testing equipment and methods are used to inspect and analyze the candidate PCB printed circuits. For example, an optical microscope can be used to observe the exposure of the photoresist, a light intensity sensor can be used to measure the cumulative exposure dose of each unit area, and image analysis software can be used to evaluate the resolution and linewidth uniformity of the circuit pattern. The test results are compared with the set exposure termination conditions to determine whether the candidate PCB printed circuit meets the exposure termination conditions. If the exposure termination conditions are not met, the optimal exposure time for each unit area needs to be dynamically optimized according to the PCB printed circuit board exposure and development method described above in this application.

[0155] If the exposure termination condition is met, the next step, development, is performed. The specific steps are as follows: First, the exposed PCB is placed in a cleaning tank, where the copper oxide layer and impurities are removed using an alkaline solution or mechanical brushing, ensuring uniform contact of the developer. Then, a weakly alkaline developer, such as sodium carbonate, is used to dissolve the dry film in the unexposed areas, preserving the cured circuit pattern. Next, the board surface is immediately rinsed with water after development to remove residual developer and dissolved dry film fragments, followed by removal of surface moisture using a high-pressure air knife or drying equipment. Finally, the exposed copper foil after development is dissolved using an acidic etching solution (such as copper chloride), retaining only the circuit areas covered by the dry film. After etching, a second cleaning and film removal are required to obtain the inner layer circuit pattern, thus obtaining the processed target PCB.

[0156] This embodiment, by dynamically optimizing the optimal exposure time for each unit area, enables more precise control over the exposure level of each unit area, avoiding circuit pattern defects such as line breaks, short circuits, and uneven line widths caused by underexposure or overexposure. This improves the exposure quality of the PCB printed circuit board and meets design requirements.

[0157] Based on the PCB printed circuit board exposure and development method, the present invention also provides a specific embodiment of a PCB printed circuit board exposure and development apparatus.

[0158] like Figure 5The diagram shows a schematic of a PCB printed circuit board exposure and development apparatus. This PCB printed circuit board exposure and development apparatus 500 includes a data acquisition module 510, a data analysis module 520, a time determination module 530, and a circuit board processing module 540.

[0159] The data acquisition module 510 is used to acquire the target light intensity data and target temperature data of each unit area of ​​the PCB printed circuit board to be processed during the exposure process. The target light intensity data includes the substrate surface light intensity when the light reaches the surface of the unit area and the exposure light intensity of the unit area.

[0160] The data analysis module 520 is used to determine the process stability parameters of each unit region based on the light intensity and target temperature data of each substrate surface. The process stability parameters are used to characterize the stability of the unit region during the exposure process.

[0161] The data analysis module 520 is also used to determine the cumulative exposure dose of each unit region based on the exposure light intensity of each unit region at each time.

[0162] The timing determination module 530 is used to determine the optimal exposure time for each unit region based on the process stability parameters of each unit region and the cumulative exposure dose of each unit region.

[0163] The circuit board processing module 540 is used to dynamically optimize the optimal exposure time of each unit area until the exposure termination condition is met, and then to develop the PCB printed circuit board to be processed to obtain the processed target PCB printed circuit board.

[0164] In the PCB printed circuit board exposure and development apparatus provided in this invention, based on the target light intensity data and target temperature data of each unit area of ​​the PCB printed circuit board to be processed during the exposure process, the process stability parameters and cumulative exposure dose of each unit area during the exposure process are analyzed. Based on the process stability parameters and cumulative exposure dose of each unit area, the optimal exposure time for each unit area is determined. Finally, the optimal exposure time of each unit area is dynamically optimized in real time until the exposure termination condition is met, at which point the PCB printed circuit board to be processed is developed to obtain the processed target PCB printed circuit board. Thus, this invention dynamically adjusts the optimal exposure time of each unit area of ​​the PCB printed circuit board to be processed based on the target light intensity data and target temperature data during the exposure process until the exposure termination condition is met. This avoids the impact of excessive or insufficient exposure time on the development process and improves the manufacturing quality of the PCB printed circuit board.

[0165] Based on the PCB printed circuit board exposure and development method, the present invention also provides a specific embodiment of a PCB printed circuit board exposure and development system.

[0166] The PCB printing circuit board exposure and development system includes a light intensity sensor, a thermal sensor, and a processor;

[0167] A light intensity sensor is used to collect target light intensity data of each unit area of ​​the PCB printed circuit board to be processed during the exposure process.

[0168] Thermal sensors are used to collect target temperature data of each unit area of ​​the PCB printed circuit board to be processed during the exposure process;

[0169] A processor for executing the PCB printed circuit board exposure and development method provided in any of the above aspects.

[0170] It should be clarified that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of the present invention.

[0171] It should also be noted that the exemplary embodiments mentioned in this invention describe methods or systems based on a series of steps or apparatus. However, this invention is not limited to the order of the steps described above; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0172] The above description is merely a specific embodiment of the present invention. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A method for exposing and developing PCB printed circuit boards, characterized in that, The method includes: The target light intensity data and target temperature data of each unit area of ​​the PCB printed circuit board to be processed are obtained during the exposure process. The target light intensity data includes the substrate surface light intensity when the light reaches the surface of the unit area and the exposure light intensity of the unit area. Based on the light intensity and target temperature data of each substrate surface, process stability parameters of each unit region are determined, and the process stability parameters are used to characterize the stability of the unit region during the exposure process. Based on the exposure light intensity of each unit region at each time, the cumulative exposure dose of each unit region is determined respectively. Based on the process stability parameters of each unit region and the cumulative exposure dose of each unit region, the optimal exposure time of each unit region is determined respectively. The optimal exposure time for each unit region is dynamically optimized until the exposure termination condition is met. Then, the PCB printed circuit board to be processed is developed to obtain the processed target PCB printed circuit board.

2. The PCB printed circuit board exposure and development method according to claim 1, characterized in that, The process stability parameters for each unit region are determined based on the light intensity and target temperature data of each substrate surface, including: Based on the light intensity of the substrate surface in each unit region, the local light intensity attenuation coefficient of each unit region is determined. The equivalent exposure dose of each unit region is determined by using the local light intensity attenuation coefficient of each unit region. Based on the line distribution information in the target unit area, the line heat accumulation coefficient of the target unit area is determined. The line heat accumulation coefficient is used to characterize the degree of heat accumulation in the target unit area during exposure. The target unit area can be any one of the unit areas. Based on the line heat accumulation coefficient of the target unit region, the target temperature data, and the equivalent exposure dose of each unit region, the process stability parameters of the target unit region are determined.

3. The PCB printed circuit board exposure and development method according to claim 2, characterized in that, The determination of the local light intensity attenuation coefficient of each unit region based on the light intensity of the substrate surface of each unit region includes: The light intensity difference between the light intensity at the light source outlet and the light intensity on the substrate surface of the unit region is obtained. The local light intensity attenuation coefficient of the unit region is determined by using the light intensity difference and the fixed optical path distance between the light source and the PCB printed circuit board to be processed.

4. The PCB printed circuit board exposure and development method according to claim 2, characterized in that, The determination of the line heat accumulation coefficient of the target unit area based on the line distribution information in the target unit area includes: Obtain the number of lines, the number of inflection points, and the line width and length of each line in the target unit area; Based on the line width and line length of each line, determine the line area of ​​each line; The heat accumulation coefficient of the target unit area is determined by using the number of lines, the number of inflection points, and the line area of ​​each line in the target unit area.

5. The PCB printed circuit board exposure and development method according to claim 2, characterized in that, The determination of process stability parameters for the target unit region based on the line heat accumulation coefficient, the target temperature data, and the equivalent exposure dose for each unit region includes: Obtain the dose standard deviation between the equivalent exposure doses of each of the unit regions; Based on the target temperature data of the target unit region, determine the maximum temperature gradient of the target unit region; The process stability parameters of the target unit region are determined using the dose standard deviation, the line heat accumulation coefficient, and the maximum temperature gradient.

6. The PCB printed circuit board exposure and development method according to any one of claims 1-5, characterized in that, The step of determining the cumulative exposure dose for each unit region based on the exposure light intensity of each unit region at each time step includes: The exposure light intensity of the unit region at each time time is integrated to obtain the integrated value of the exposure light intensity. The cumulative exposure dose of the unit region is determined by using the integral value of the exposure light intensity and the local light intensity attenuation coefficient of the unit region.

7. The PCB printed circuit board exposure and development method according to any one of claims 1-5, characterized in that, The determination of the optimal exposure time for each unit region based on the process stability parameters and the cumulative exposure dose of each unit region includes: Based on the process stability parameters of the unit region and the cumulative exposure dose, an objective function corresponding to the exposure time of the unit region is constructed. The optimal exposure time for the unit region is determined using an objective function corresponding to the exposure time of the unit region.

8. The PCB printed circuit board exposure and development method according to any one of claims 1-5, characterized in that, The process of dynamically optimizing the optimal exposure time for each of the aforementioned unit regions until the exposure termination condition is met, followed by developing the PCB printed circuit board to be processed to obtain the processed target PCB printed circuit board, includes: Based on the optimal exposure time of each unit region, the PCB printed circuit to be processed is exposed to obtain the candidate PCB printed circuit. Based on the candidate PCB printed circuit, determine whether the exposure termination condition is met; If the exposure termination condition is not met, the optimal exposure time for each unit region is dynamically optimized, and the process is returned to perform exposure processing on the PCB printed circuit to be processed based on the optimal exposure time for each unit region. If the exposure termination condition is met, the candidate PCB printed circuit is developed to obtain the processed target PCB printed circuit board.

9. A PCB printed circuit board exposure and development apparatus, characterized in that, The device includes: The data acquisition module is used to acquire the target light intensity data and target temperature data of each unit area of ​​the PCB printed circuit board to be processed during the exposure process. The target light intensity data includes the substrate surface light intensity when the light reaches the surface of the unit area and the exposure light intensity of the unit area. The data analysis module is used to determine the process stability parameters of each unit region based on the light intensity and target temperature data of each substrate surface. The process stability parameters are used to characterize the stability of the unit region during the exposure process. The data analysis module is also used to determine the cumulative exposure dose of each unit region based on the exposure light intensity of each unit region at each time. The time determination module is used to determine the optimal exposure time for each of the unit regions based on the process stability parameters of each unit region and the cumulative exposure dose of each unit region. The circuit board processing module is used to dynamically optimize the optimal exposure time of each unit area until the exposure termination condition is met, and then to perform development processing on the PCB printed circuit board to be processed to obtain the processed target PCB printed circuit board.

10. A PCB printed circuit board exposure and development system, characterized in that, The system includes a light intensity sensor, a thermal sensor, and a processor; The light intensity sensor is used to collect target light intensity data of each unit area of ​​the PCB printed circuit board to be processed during the exposure process. The thermal sensor is used to collect target temperature data of each unit area of ​​the PCB printed circuit board to be processed during the exposure process. The processor is used to execute the PCB printed circuit board exposure and development method according to any one of claims 1-8.

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