Multi-exposure offset method for improving printed circuit board (PCB) ink chromatic aberration and medium

Abstract

The invention discloses a multi-exposure offset method for improving PCB ink color difference and a medium. The multi-exposure offset method comprises the following steps: preparing a PCB substrate coated with ink; determining the power ratio of a plurality of lasers in the laser direct imaging equipment; an exposure parameter set corresponding to the multiple exposure modes is established, the exposure parameter set at least comprises an exposure dose parameter and an exposure starting point offset parameter, and the total exposure dose of the multiple exposure modes is equivalent to the single exposure dose required for improving the chromatic aberration target; based on the exposure parameter set, the laser direct imaging equipment is controlled to execute at least two times of exposure operation on the same target pattern area on the PCB substrate, and the starting point positions of the exposure operation are different from one another. According to the invention, multiple exposure is carried out by setting different starting points for the same pattern area, so that the light path energy is dispersed and homogenized, the chromatic aberration in PCB ink exposure is efficiently compensated, and the product yield is improved.

Description

Technical Field

[0001] This invention relates to the field of PCB manufacturing technology, and in particular to a method and medium for improving color difference in PCB inks through multiple exposure offset. Background Technology

[0002] In PCB manufacturing, the precision machining of high-density interconnect (HDI) boards and integrated circuit packaging substrates places extremely high demands on the accuracy of the patterning system, directly impacting product yield. Currently, mainstream pattern transfer technologies mainly include mask projection exposure systems and digital laser direct writing (LDI) systems. The latter uses computer-controlled laser beams in conjunction with dynamic mask technology to directly scan patterns onto the surface of photosensitive materials, offering high flexibility. However, digital laser direct writing systems typically employ multiple optical paths for exposure. Due to uneven energy distribution, color differences easily arise between different optical paths, especially when exposing ink solder resist layers, leading to a decrease in product yield.

[0003] Existing technologies often employ grayscale compensation methods to improve color difference, which involves controlling local energy by adjusting the number of DMD micromirrors flipped at the optical path connection. However, this method has the following drawbacks: first, it cannot precisely control the number of DMD micromirrors flipped in the color difference area to achieve completely uniform energy; second, its effect on improving color difference is limited, making it difficult to meet the requirements of high-precision PCB manufacturing. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology. To achieve the above objective, a multiple exposure offset method and medium for improving the color difference of PCB ink are adopted to solve the problems mentioned in the background technology.

[0005] A multi-exposure offset method for improving color difference in PCB inks includes the following steps:

[0006] Prepare the PCB substrate coated with ink; Determine the power ratio of multiple lasers in a laser direct imaging device; Establish an exposure parameter set corresponding to the multiple exposure mode, wherein the exposure parameter set includes at least an exposure dose parameter and an exposure start point offset parameter, and the total exposure dose of the multiple exposure mode is equivalent to the single exposure dose required to improve the color difference target; Based on the exposure parameter set, the laser direct imaging device is controlled to perform at least two exposure operations on the same target pattern area on the PCB substrate, and the starting point position of each exposure operation is different.

[0007] As a further aspect of the present invention: the step of determining the power ratio of the laser includes: Identify and store the current power configuration parameters of each laser in the laser direct imaging device.

[0008] As a further aspect of the present invention: the step of establishing the exposure parameter set includes: In the control system of the laser direct imaging device, a dry film part number is created or called, and the power ratio information is associated with the dry film part number.

[0009] As a further aspect of the present invention: in the dry film part number, the sum of the exposure doses defined for the at least two exposure operations is equal to the target exposure dose defined for a single exposure operation.

[0010] As a further aspect of the present invention, it also includes: Based on the design data of the pattern to be exposed, an exposure pattern part number is created or called, and the exposure pattern part number is associated with the dry film part number.

[0011] As a further aspect of the present invention: in the at least two exposure operations, the starting point positions of each exposure operation are staggered according to a preset offset rule, which is set based on the historical color difference distribution characteristics or theoretical optical path energy model on the PCB substrate.

[0012] As a further aspect of the present invention: the exposure start point offset is 5mm to 50mm.

[0013] As a further aspect of the present invention, it also includes: During the at least two exposure operations, a grayscale compensation function based on the adjustment of the number of micromirrors flipped by the digital micromirror device (DMD) is simultaneously enabled.

[0014] As a further aspect of the present invention: the exposure is performed under yellow light.

[0015] The second aspect of the technical solution: a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method as described in any of the above.

[0016] Compared with the prior art, the present invention has the following technical advantages: The above technical solution involves preparing an ink-coated PCB substrate and determining the power ratio of each laser in the laser direct imaging device. The core is establishing a parameter set that includes exposure dose and exposure start-point offset, where the total exposure dose is set to be equivalent to the single-exposure target dose required to improve color difference. Based on this parameter set, the control device performs at least two exposures on the same target pattern area on the substrate, with the start-point positions of each exposure staggered. This solution cleverly changes the start position of each exposure and rationally distributes the exposure energy, thus dispersing and homogenizing the exposure accumulation effect that might otherwise be concentrated in a fixed area due to uneven energy distribution in the optical path, effectively compensating for color differences between different optical paths. Attached Figure Description

[0017] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the structure of an embodiment disclosed in this application; Figure 2 This is a flowchart illustrating a multi-exposure offset method according to an embodiment of this application. Figure 3 This is a developed product image without an exposure origin offset, according to an embodiment of this application. Figure 4 This is a development product diagram showing the setting of a suitable exposure origin offset according to an embodiment of this application. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Please refer to Figure 1 and Figure 2 In this embodiment of the invention, a multiple exposure offset method for improving color difference in PCB inks includes the following steps: Step S1: Prepare a PCB substrate coated with ink; Step S2: Determine the power ratio of multiple lasers in the laser direct imaging device; The steps for determining the power ratio of the laser include: Identify and store the current power configuration parameters of each laser in the laser direct imaging device.

[0020] Step S3: Establish an exposure parameter set corresponding to the multiple exposure mode, wherein the exposure parameter set includes at least an exposure dose parameter and an exposure start point offset parameter, and the total exposure dose of the multiple exposure mode is equivalent to the single exposure dose required to improve the color difference target. The steps for establishing the exposure parameter set include: In the control system of the laser direct imaging device, a dry film part number is created or called, and the power ratio information is associated with the dry film part number.

[0021] In this embodiment, in the dry film part number, the sum of the exposure doses defined for the at least two exposure operations is equal to the target exposure dose defined for a single exposure operation.

[0022] Step S4: Based on the exposure parameter set, control the laser direct imaging device to perform at least two exposure operations on the same target pattern area on the PCB substrate, and the starting point position of each exposure operation is different.

[0023] This embodiment also includes: Based on the design data of the pattern to be exposed, an exposure pattern part number is created or called, and the exposure pattern part number is associated with the dry film part number.

[0024] In this embodiment, in the at least two exposure operations, the starting point positions of each exposure operation are staggered according to a preset offset rule, which is set based on the historical color difference distribution characteristics or theoretical optical path energy model on the PCB substrate.

[0025] In this embodiment, the exposure start point offset is 5mm to 50mm.

[0026] This embodiment also includes: During the at least two exposure operations, a grayscale compensation function based on the adjustment of the number of micromirrors flipped by the digital micromirror device (DMD) is simultaneously enabled.

[0027] In this embodiment, the exposure is performed under yellow light.

[0028] Example 2: The specific steps in this embodiment are as follows: First, prepare a PCB substrate that has been coated with ink.

[0029] Subsequently, the current power ratio of each laser in the laser direct imaging equipment was confirmed and recorded.

[0030] The core operation lies in parameter setting: creating a new dry film part number and associating it with the recorded equipment information; Based on the target total exposure dose (1200 mJ in this example), a secondary exposure mode is set, and three different dose distribution combinations are tried respectively (300 mJ + 1000 mJ, 400 mJ + 900 mJ, 500 mJ + 800 mJ). Exposure origin offset is not enabled in this mode.

[0031] Next, an exposure part number is created based on the graphic requirements and associated with the aforementioned dry film part number.

[0032] Finally, exposure was performed under yellow light to project the pattern onto the substrate. After development and comparison, it was found that... Figure 3 As shown in the figure, the developed product image is without setting the exposure origin offset (the framed area is the color difference at the stitching). All combinations improved the color difference, with the dosage distribution of 500 mJ + 800 mJ showing the best effect. The other two combinations still had slight color difference at the stitching.

[0033] Example 2: This embodiment further demonstrates the optimization effect of introducing an exposure start point offset. After completing substrate preparation and confirming the laser power ratio as described in Embodiment 2, the core parameters are configured: Create a new dry film part number and associate it with the equipment information; With the total exposure dose being 1200 mJ, not only were three combinations of secondary exposure doses set (300 mJ + 1000 mJ, 400 mJ + 900 mJ, 500 mJ + 800 mJ), but more importantly, a 20 mm exposure origin offset was enabled.

[0034] Subsequently, an exposure pattern part number associated with this dry film part number was established, and exposure was performed under yellow light. The results after development showed that, as Figure 4 As shown in the figure, the developed product image is shown with the exposure origin offset set (the framed area is the area of ​​color difference). After setting a reasonable exposure origin offset, the color difference improvement effect is significantly improved. The exposure images obtained by the three dosage distribution schemes mentioned above are almost without color difference, which verifies the effectiveness of the comprehensive scheme combining dosage distribution and origin offset in eliminating color difference.

[0035] In this embodiment, the beneficial effects are as follows: This method improves color difference in ink products by performing multiple exposures by changing the exposure start point setting. It utilizes the adjustable exposure origin mechanism of laser imaging equipment to set appropriate multiple exposure origins and energy for the exposed product, thereby improving color difference. Compared to traditional methods (such as grayscale compensation), this method offers advantages such as convenient operation and settings, significant color difference optimization, low development cost, and the ability to be used in conjunction with traditional methods. It better meets the needs of PCB manufacturers for improving product color difference and increasing product yield.

[0036] The second aspect of the technical solution: a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method as described in any of the above.

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention. The scope of the invention is defined by the appended claims and their equivalents, all of which should be included within the scope of protection of the invention.

Claims

1. A multi-exposure offset method for improving color difference in PCB inks, characterized in that, Includes the following steps: Prepare the PCB substrate coated with ink; Determine the power ratio of multiple lasers in a laser direct imaging device; Establish an exposure parameter set corresponding to the multiple exposure mode, wherein the exposure parameter set includes at least an exposure dose parameter and an exposure start point offset parameter, and the total exposure dose of the multiple exposure mode is equivalent to the single exposure dose required to improve the color difference target; Based on the exposure parameter set, the laser direct imaging device is controlled to perform at least two exposure operations on the same target pattern area on the PCB substrate, and the starting point position of each exposure operation is different.

2. The multiple exposure offset method for improving PCB ink color difference according to claim 1, characterized in that, The step of determining the power ratio of the laser includes: Identify and store the current power configuration parameters of each laser in the laser direct imaging device.

3. The multiple exposure offset method for improving PCB ink color difference according to claim 1, characterized in that, The steps for establishing the exposure parameter set include: In the control system of the laser direct imaging device, a dry film part number is created or called, and the power ratio information is associated with the dry film part number.

4. The multiple exposure offset method for improving PCB ink color difference according to claim 3, characterized in that, In the dry film part number, the sum of the exposure doses defined for the at least two exposure operations is equal to the target exposure dose defined for a single exposure operation.

5. The multiple exposure offset method for improving PCB ink color difference according to claim 4, characterized in that, Also includes: Based on the design data of the pattern to be exposed, an exposure pattern part number is created or called, and the exposure pattern part number is associated with the dry film part number.

6. The multiple exposure offset method for improving PCB ink color difference according to claim 1, characterized in that, In the at least two exposure operations, the starting point positions of each exposure operation are staggered according to a preset offset rule, which is set based on the historical color difference distribution characteristics or theoretical optical path energy model on the PCB substrate.

7. The multiple exposure offset method for improving PCB ink color difference according to claim 6, characterized in that, The exposure start point offset is 5mm to 50mm.

8. The multiple exposure offset method for improving PCB ink color difference according to claim 1, characterized in that, Also includes: During the at least two exposure operations, a grayscale compensation function based on the adjustment of the number of micromirrors flipped by the digital micromirror device (DMD) is simultaneously enabled.

9. The multiple exposure offset method for improving PCB ink color difference according to claim 1, characterized in that, The exposure was performed under yellow light.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 9.

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