Circuit board and design method thereof

Abstract

The invention discloses a circuit board and a design method thereof, and the method comprises the steps: obtaining the original design parameters of the circuit board, and the original design parameters at least comprise the design size of the circuit board; according to the original design parameters, dividing one side surface of the circuit board into at least two sub-regions; the area of the sub-region is smaller than the design area of the circuit board; according to the original design parameters and the area of each sub-region, determining laying parameters of each metal layer in the sub-region; the original design parameters further comprise the original thickness and the set area of each metal layer in each sub-region; the laying parameters comprise laying thickness and / or laying area. According to the technical scheme, the warping risk of the circuit board can be reduced, and the flatness of the circuit board is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit boards, and in particular to a circuit board and a design method thereof. Background Art

[0002] Printed Circuit Board (PCB) is made of copper foil, resin and other materials. Due to the different physical and chemical properties of each material, it will cause deformation under the action of stress after pressing, causing the PCB to warp, affecting the reliability of subsequent devices mounted on the PCB surface.

[0003] When mounting components on the surface of a circuit board, if the circuit board is not flat, it will cause inaccurate positioning, and the components cannot be inserted into the holes of the circuit board or mounted on the mounting pads of the circuit board, resulting in reduced reliability of PCB assembly components. Therefore, how to reduce the warpage of the PCB has become a technical problem that needs to be solved. Summary of the invention

[0004] The invention provides a circuit board and a design method thereof, which can improve the flatness of the circuit board.

[0005] In a first aspect, the present invention provides a circuit board design method, comprising:

[0006] Acquire original design parameters of the circuit board; the original design parameters at least include the design size of the circuit board;

[0007] According to the original design parameters, a surface of one side of the circuit board is divided into at least two sub-areas; the area of ​​the sub-areas is smaller than the design area of ​​the circuit board;

[0008] The laying parameters of each metal layer in the sub-area are determined according to the original design parameters and the area of ​​each sub-area; the original design parameters also include the original thickness and setting area of ​​each metal layer in each sub-area; the laying parameters include laying thickness and / or laying area.

[0009] Optionally, determining the laying parameters of each metal layer in each sub-region according to the original design parameters and the area of ​​each sub-region includes:

[0010] Determining the middle plane of the circuit board according to the original design parameters; the design dimensions include the design thickness;

[0011] Determine, according to the intermediate plane and the original design parameters, correction parameters of at least part of the metal layer in the sub-region; the correction parameters include a correction thickness and / or a correction area;

[0012] The laying parameters of each metal layer in each sub-region are determined according to the area of ​​each sub-region, the original design parameters and the modified parameters.

[0013] Optionally, determining, according to the middle plane and the original design parameters, correction parameters of at least part of the metal layer in the sub-region includes:

[0014] Determine, according to the middle plane and the original design parameters, a first metal volume of a first part and a second metal volume of a second part of the sub-region; the first part is a part of the circuit board located on a first side of the middle plane, and the second part is a part of the circuit board located on a second side of the middle plane; in a thickness direction of the circuit board, the first side and the second side are arranged opposite to each other;

[0015] A correction parameter of at least a portion of the metal layer in the sub-region is determined according to the first metal volume and the second metal volume.

[0016] Optionally, determining a first metal volume of a first part and a second metal volume of a second part of the sub-region according to the middle plane and the original design parameters includes:

[0017] Determine, according to the middle plane and the original design parameters, each first metal sub-volume in each metal layer in the first portion and each second metal sub-volume in each metal layer in the second portion;

[0018] determining the first metal volume according to each of the first metal sub-volumes in each of the metal layers in the first portion;

[0019] The second metal volume is determined according to each of the second metal sub-volumes in each of the metal layers in the second portion.

[0020] Optionally, determining, according to the first metal volume and the second metal volume, correction parameters of at least part of the metal layer in the sub-region includes:

[0021] Determining whether an absolute value of a difference between the first metal volume and the second metal volume is greater than a first preset difference;

[0022] If yes, the portion of the circuit board corresponding to the larger of the first metal volume and the second metal volume is determined as the portion to be reduced and adjusted, and the portion of the circuit board corresponding to the smaller of the first metal volume and the second metal volume is determined as the portion to be increased and adjusted;

[0023] The correction parameter of the portion to be reduced or the portion to be increased is determined according to the first metal volume and the second metal volume.

[0024] Optionally, determining the correction parameter of the portion to be reduced or the portion to be increased according to the first metal volume and the second metal volume includes:

[0025] Calculating an absolute value of a volume difference between the first metal volume and the second metal volume;

[0026] The corrected thickness of the portion to be increased is determined according to the absolute value of the volume difference and the area of ​​the sub-region; or the corrected area of ​​the portion to be decreased is determined according to the absolute value of the volume difference and the thickness of each metal layer in the sub-region.

[0027] Optionally, determining the laying parameters of each metal layer in each sub-region according to the area of ​​each sub-region, the original design parameter and the modified parameter includes:

[0028] Determine the metal volume and total volume of the sub-region according to the area of ​​the sub-region, the original design parameters and the modified parameters; the metal volume of the sub-region is the total metal volume of the sub-region, and the total volume of the sub-region is the total volume of the sub-region;

[0029] Determining a metal volume ratio of the sub-region according to the metal volume of the sub-region and the total volume of the region;

[0030] Determine whether the absolute value of the ratio difference of the metal volume ratios corresponding to two adjacent sub-regions is less than or equal to a second preset difference;

[0031] If so, the laying parameters of each metal layer in the sub-area are determined according to the original design parameters and the modified parameters of each metal layer in the sub-area.

[0032] Optionally, if the absolute value of the ratio difference of the metal volume ratios corresponding to two adjacent sub-regions is greater than the second preset difference; then the adjusted metal volume ratio of the sub-region is determined according to the absolute value of the ratio difference and the second preset difference;

[0033] Determine the sub-region having the larger metal volume ratio in two adjacent sub-regions as the sub-region to be reduced;

[0034] Determining the metal reduction volume of the sub-region to be reduced according to the adjusted metal volume ratio and the total volume of the sub-region to be reduced;

[0035] According to the metal reduction volume, the number and size of holes to be dug in at least part of the metal layer in the sub-area to be reduced are determined; the laying parameters also include the number and size of holes to be dug.

[0036] Optionally, determining the metal volume and the total volume of the sub-region according to the area of ​​the sub-region, the original design parameter and the modified parameter includes:

[0037] Determining the metal volume of the sub-region according to the original design parameters and the correction coefficient;

[0038] The total volume of the sub-region is determined according to the area of ​​the sub-region and the original design parameters.

[0039] In a second aspect, the present invention provides a circuit board, which is designed using the circuit board design method described in the first aspect.

[0040] The technical solution provided by the present invention obtains the original design parameters of the circuit board and divides one side surface of the circuit board into at least two sub-areas according to the original design parameters, so as to adjust the metal laying thickness or laying area of ​​each metal layer in the sub-area according to the metal volume in the sub-area, so as to balance the metal volume difference within the sub-area and the metal volume difference between the sub-areas, reduce the stress difference caused by the different metal volumes, thereby reducing the risk of warping of the circuit board and improving the flatness of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A flow chart of a circuit board design method provided by an embodiment of the present invention;

[0042] Figure 2 A flow chart of another circuit board design method provided by an embodiment of the present invention;

[0043] Figure 3 A flowchart of another circuit board design method provided by an embodiment of the present invention;

[0044] Figure 4 A flowchart of another circuit board design method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0046] The present invention provides a method for preparing a circuit board, which is suitable for designing a circuit board with a relatively low warpage. Figure 1 A flow chart of a circuit board design method provided by an embodiment of the present invention includes:

[0047] S11. Obtain original design parameters of the circuit board.

[0048] The original design parameters at least include the design size of the circuit board.

[0049] Specifically, the design size of the circuit board can be set according to actual needs. For example, the design size of the circuit board is 10cm*5cm, that is, the design length of the circuit board is 10cm and the design width of the circuit board is 5cm.

[0050] S12. Divide a surface of one side of the circuit board into at least two sub-areas according to original design parameters.

[0051] The area of ​​the sub-region is smaller than the design area of ​​the circuit board. The design area of ​​the circuit board can be calculated by the design size of the circuit board. For example, if the design size of the circuit board is 10cm*5cm, then the design area of ​​the circuit board is 50cm 2 .

[0052] Specifically, the division method of the sub-area can be set according to the design size of the circuit board. When the design size of the circuit board is a*b, the design size of the sub-area can be (a / 2)*(b / 2). At this time, the surface shape of the circuit board and the shape of the sub-area are both rectangular. On the premise that the design size of the sub-area does not exceed the design size of the circuit board, the shape of the sub-area can be set according to actual needs. The shape of the sub-area can also be square or circular, etc., which can be set according to actual needs. By dividing the circuit board into sub-areas, the laying parameters of each metal layer in the sub-area can be determined based on the volume difference of the metal layer inside the sub-area and / or the volume difference of the metal layer between the sub-areas, so as to evenly distribute the metal layers between the sub-areas in the circuit board, reduce the risk of warping of the circuit board, and improve the flatness of the circuit board.

[0053] It can be understood that, under the premise of setting at least two sub-regions, the areas of each sub-region can be the same or different. When the sub-regions have the same area, since the design area of ​​the circuit board is fixed, the more sub-regions are set, the smaller the area of ​​the sub-region will be, so as to improve the accuracy of determining the laying parameters of each metal layer in the subsequent sub-regions.

[0054] S13. Determine the laying parameters of each metal layer in the sub-region according to the original design parameters and the area of ​​each sub-region.

[0055] The original design parameters also include the original thickness and setting area of ​​each metal layer in each sub-area. The laying parameters include laying thickness and / or laying area. For the same sub-area, the original thickness of each metal layer may be the same or different, which is related to the design requirements of the circuit board. For the same metal layer, the thickness in each sub-area may also be the same or different, which is related to the design requirements of the circuit board.

[0056] Specifically, the circuit board is divided into sub-areas so as to determine the original metal volume of each sub-area according to the original thickness and setting area of ​​each metal layer in each sub-area, and then compare the original metal volume of each sub-area or evaluate the metal volume of the upper and lower parts of the same sub-area, and then adjust the original thickness of each metal layer in the sub-area or the setting area of ​​the metal in the metal layer according to the comparison result or the evaluation result, and determine the laying thickness and / or laying area of ​​the metal layer to balance the volume difference of the metal layer within each sub-area or between each sub-area, thereby reducing the risk of warping of the circuit board, improving the flatness of the circuit board, and improving the reliability of subsequent assembly devices.

[0057] The technical solution of the embodiment of the present invention obtains the original design parameters of the circuit board and divides one side surface of the circuit board into at least two sub-areas according to the original design parameters, so as to adjust the metal laying thickness or laying area of ​​each metal layer in the sub-area according to the metal volume in the sub-area, so as to balance the metal volume difference within the sub-area and the metal volume difference between the sub-areas, reduce the stress difference caused by the different metal volumes, thereby reducing the risk of warping of the circuit board and improving the flatness of the circuit board.

[0058] In an optional embodiment, based on the above embodiment, the embodiment of the present invention describes the situation of determining the laying parameters of each metal layer in each sub-region according to the original design parameters and the area of ​​each sub-region. Figure 2 A flowchart of another circuit board design method provided by an embodiment of the present invention, such as Figure 2 As shown, the design method includes:

[0059] S21. Obtain original design parameters of the circuit board.

[0060] The original design parameters at least include the design size of the circuit board.

[0061] S22. Divide a surface of one side of the circuit board into at least two sub-areas according to original design parameters.

[0062] The area of ​​the sub-region is smaller than the design area of ​​the circuit board.

[0063] S23. Determine the middle plane of the circuit board based on the original design parameters.

[0064] Among them, the design size includes the design thickness, that is, the design thickness of the circuit board. When designing a circuit board, in order to avoid a short circuit caused by direct electrical connection between two adjacent metal layers, a dielectric layer is set between the two adjacent metal layers. The original thickness of each dielectric layer can be the same or different. When the thickness of each dielectric layer is different, in order to avoid the dielectric layer affecting the flatness of the circuit board, the dielectric layer is usually set to a symmetrical structure, that is, the first dielectric layer has the same thickness as the Nth dielectric layer, and the second dielectric layer has the same thickness as the N-1th dielectric layer. N is the number of dielectric layers set. The thickness mentioned above is the average thickness of the dielectric layer. Due to the different design requirements of the circuit board for each metal layer, the dielectric layer is required to make up for the thinner area of ​​the metal layer, so that some areas of the same metal layer have a large thickness and some areas have a small thickness.

[0065] Specifically, according to the design thickness of the circuit board, the plane where the middle point of the design thickness is located is taken as the middle plane. For example, the design thickness of the circuit board is d, then in the thickness direction of the circuit board, the plane with a distance of d / 2 from the upper surface or the lower surface of the circuit board is the middle plane, so that the circuit boards in each sub-area can be further divided according to the middle plane to balance the metal volume on both sides of the middle plane, reduce the risk of bending and warping of the circuit board, reduce the deformation of the circuit board, and improve the flatness of the circuit board.

[0066] It should be noted that the original design parameters of the circuit board do not involve the through hole design parameters or blind hole and buried hole design parameters of the circuit board, so only metal materials such as copper are laid in each metal layer of each sub-area.

[0067] S24. Determine correction parameters of at least part of the metal layer in the sub-region according to the middle plane and the original design parameters.

[0068] The correction parameters include correction thickness and / or correction area.

[0069] Specifically, the original design parameters include the original thickness and setting area of ​​each metal layer in the sub-region, so the total metal volume of the circuit board on one side of the middle plane in the sub-region and the total metal volume of the circuit board on the other side of the middle plane can be calculated, and the difference in the total metal volume of the circuit boards on both sides of the middle plane is compared. According to the degree of difference, the corrected thickness and / or corrected area of ​​the metal layer on one side or both sides of the middle plane in the sub-region is determined, so that after correcting some metal layers in the sub-region according to the correction parameters, the total metal volumes on both sides of the middle plane are equal or have a small difference, thereby reducing the stress difference in the thickness direction of the circuit board, preventing each sub-region from bending and deforming, and thereby improving the flatness of the circuit board.

[0070] S25. Determine the laying parameters of each metal layer in each sub-region according to the area of ​​each sub-region, the original design parameters and the modified parameters.

[0071] The laying parameters include laying thickness and / or laying area.

[0072] Specifically, according to the correction parameters of some metal layers in the sub-region and the design thickness of each metal layer in the relevant sub-region in the original design parameters, the thickness and area of ​​each metal layer in the sub-region after correction can be determined, and the metal volume of the sub-region can be determined according to the thickness and area of ​​each metal layer in the sub-region after correction. The total volume of the sub-region is determined according to the area of ​​the sub-region and the design thickness of the circuit board in the original design parameters, the metal ratio of the metal volume in the sub-region to the total volume is calculated, the metal ratio of each sub-region is compared, and the thickness and area of ​​the metal layer in the sub-region are further adjusted according to the degree of difference in the metal ratio of each sub-region. The adjusted thickness and area are used as the laying parameters of the metal layer, so that the metal volume ratio between each sub-region of the circuit board with the laying parameters is within a preset range, so as to reduce the deformation of the circuit board caused by the uneven metal volume ratio between the sub-regions and the sub-regions, and further improve the flatness of the circuit board.

[0073] The technical solution of the embodiment of the present invention determines the middle plane of the circuit board through the original design parameters, and then determines the metal volume difference of the circuit board located on both sides of the middle plane in the sub-region according to the middle plane and the original design parameters, so as to determine the correction parameters of part of the metal layer on one side or both sides of the middle plane according to the metal volume difference, so as to balance the stress generated by the metal layer on both sides of the middle plane, reduce the warping of the circuit board caused by stress imbalance, and improve the flatness of each sub-region; then, according to the area of ​​each sub-region, the original design parameters and the correction parameters, the metal volume ratio difference between the sub-regions is determined, and then the thickness and area of ​​each metal layer in the sub-region are adjusted to determine the laying parameters of each metal layer, so as to reduce the stress difference between the sub-regions, balance the stress between the sub-regions, further reduce the risk of warping of the circuit board, and improve the flatness of the circuit board.

[0074] In an optional embodiment, based on the above embodiment, the embodiment of the present invention describes the situation of determining the correction parameters of at least part of the metal layer in the sub-region according to the middle plane, the area of ​​each sub-region and the original design parameters. Figure 3 A flowchart of another circuit board design method provided by an embodiment of the present invention is as follows: Figure 3 As shown, the design method includes:

[0075] S31. Obtain original design parameters of the circuit board.

[0076] The original design parameters at least include the design size of the circuit board.

[0077] S32. Divide a surface of one side of the circuit board into at least two sub-areas according to original design parameters.

[0078] The area of ​​the sub-region is smaller than the design area of ​​the circuit board.

[0079] S33. Determine the middle plane of the circuit board based on the original design parameters.

[0080] The original design parameters also include the design thickness of the circuit board.

[0081] S34. Determine a first metal volume of the first part and a second metal volume of the second part in the sub-region according to the middle plane and the original design parameters.

[0082] The first part is a portion of the circuit board located on a first side of the middle plane, and the second part is a portion of the circuit board located on a second side of the middle plane. In the thickness direction of the circuit board, the first side and the second side are arranged opposite to each other.

[0083] Specifically, the first part and the second part are respectively located on both sides of the middle plane, so the amount of metal set in the first part, that is, the first metal volume, and the amount of metal set in the second part, that is, the second metal volume, can be determined according to the original design parameters, and the volume is related to the thickness and the bottom area. When the setting area of ​​each metal layer in the sub-region is equal to the area of ​​the sub-region, the thickness of each metal layer in the first part can be added, and the product of the added sum and the area of ​​the sub-region is the first metal volume of the first part. When the setting area of ​​each metal layer in the sub-region is less than or greater than the area of ​​the sub-region, the metal volume of each metal layer can be calculated, and the metal volume of each metal layer can be summed to determine the first metal volume and the second metal volume.

[0084] It can be understood that when there is a metal layer in a sub-region with a setting area larger than the area of ​​the sub-region, it means that a conductive hole is set in the dielectric layer below the metal layer, and the setting area of ​​the metal layer includes the setting area of ​​the metal in the conductive hole below connected to the metal layer.

[0085] In an optional embodiment, the first metal volume of the first part and the second metal volume of the second part of the sub-area are determined according to the middle plane and the original design parameters, including determining each first metal sub-volume in each metal layer in the first part and the second metal sub-volume in each metal layer in the second part according to the middle plane and the original design parameters; determining the first metal volume according to each first metal sub-volume in each metal layer in the first part; and determining the second metal volume according to each second metal sub-volume in each metal layer in the second part.

[0086] Specifically, the original design parameters include the original thickness and setting area of ​​each metal layer in the sub-region. Taking the determination of the first metal volume of the first part as an example, if the original thickness of each position in the same metal layer in the sub-region is consistent, the product of the original thickness and the design area can be used as the first metal sub-volume of the metal layer. If the same metal layer in the sub-region includes metal parts with different thicknesses and different setting areas, the setting areas of the metal parts with the same thickness can be summed, and the product of the sum and the thickness can be used as the metal volume of the metal part with the same thickness. The metal volumes of other metal parts with the same thickness can also be calculated according to the above principle, and then the sum of the calculated metal volumes is used as the first metal sub-volume of the metal layer. The first metal sub-volumes in the first part are summed, and the sum value is the first metal volume of the first part.

[0087] It should be noted that the above description is only an exemplary description based on the example of determining the first metal volume of the first part. The principle of determining the second metal volume of the second part is similar to the principle of determining the first metal volume. Please refer to the above description and will not be repeated here.

[0088] S35, determining whether the absolute value of the difference between the first metal volume and the second metal volume is greater than a first preset difference; if so, executing S36.

[0089] The first preset difference can be set according to actual needs, and the first preset difference can be set from 0mm to 3 ~0.3mm 3 For example, the first preset difference is 0.3 mm. 3 .

[0090] Specifically, the difference between the first metal volume and the second metal volume is calculated, and the value after taking the absolute value of the difference is taken as the absolute value of the difference. When the absolute value of the difference is less than or equal to the first preset difference, it means that the difference between the first metal volume and the second metal volume is small, that is, the difference in the metal volume of the first part and the second part is small. At this time, the stress of the first part and the second part is relatively balanced, and there is no need to correct the metal layer thickness and setting area of ​​the first part or the second part. When the absolute value of the difference is greater than the first preset difference, it means that the difference between the first metal volume and the second metal volume is large, that is, the difference in the metal volume of the first part and the second part is large. At this time, the stress of the first part and the second part is unbalanced, and the metal layer thickness and setting area of ​​the first part or the second part need to be corrected to reduce the risk of circuit board bending due to unbalanced stress.

[0091] S36. Determine a portion of the circuit board corresponding to the larger of the first metal volume and the second metal volume as the portion to be reduced and adjusted, and determine a portion of the circuit board corresponding to the smaller of the first metal volume and the second metal volume as the portion to be increased and adjusted.

[0092] Specifically, the first metal volume and the second metal volume are compared. The portion of the circuit board corresponding to the metal volume with a larger value has a larger metal volume, and the portion of the circuit board corresponding to the metal volume with a smaller value has a smaller metal volume. In order to balance the metal volume of the first part and the second part, the portion of the circuit board with a larger metal volume can be determined as the portion to be reduced, that is, the metal design amount in this portion of the circuit board needs to be reduced. The portion of the circuit board with a larger metal volume is determined as the portion to be increased, that is, the metal design amount in this portion of the circuit board needs to be increased. The metal design amount is related to the metal design thickness and the metal setting area.

[0093] S37. Determine correction parameters of the portion to be reduced or increased according to the first metal volume and the second metal volume.

[0094] Specifically, the absolute value of the difference between the first metal volume and the second metal volume can be used as the metal volume increase of the part to be reduced or as the metal volume reduction of the part to be increased. For the part to be reduced, holes can be designed and drilled in part or all of the metal layers of the part to be reduced in an area that does not affect the electrical function of the part to be reduced. The number and size of the holes are determined by the metal volume reduction, so that the metal volume of the drilled part is consistent with the metal volume reduction, thereby reducing the metal volume difference between the first part and the second part, balancing the stress of the first part and the second part, reducing the risk of warping of the circuit board, and improving the flatness of the circuit board. For the part to be increased, the design thickness and / or setting area of ​​the metal can be increased in part or all of the metal layers of the part to be increased in an area that does not affect the electrical function of the part to be reduced. The increase in thickness and / or area of ​​the metal layer is determined by the increase in metal volume, so that the metal volume of the increased metal is consistent with the metal volume reduction, thereby reducing the metal volume difference between the first part and the second part, balancing the stress of the first part and the second part, reducing the risk of warping of the circuit board, and improving the flatness of the circuit board.

[0095] Optionally, correction parameters of the part to be reduced or the part to be increased are determined based on the first metal volume and the second metal volume, including calculating the absolute value of the volume difference between the first metal volume and the second metal volume; determining the corrected thickness of the part to be increased based on the absolute value of the volume difference and the area of ​​the sub-region; or determining the corrected area of ​​the part to be reduced based on the absolute value of the volume difference and the thickness of each metal layer in the sub-region.

[0096] Specifically, when the thickening of the metal layer on the surface of the circuit board does not affect the function of the circuit board, the ratio of the absolute value of the volume difference to the area of ​​the sub-region can be used as the corrected thickness of the metal layer on the surface of the circuit board. In the thickness direction of the circuit board, when the non-functional areas in the metal layers overlap, the total thickness of the metal layers in the non-functional areas can be calculated, and the ratio of the absolute value of the volume difference to the total thickness can be used as the corrected area of ​​the non-functional areas; or the total thickness of the continuous interval of the partial metal layer can be calculated, and the ratio of the absolute value of the volume difference to the total thickness can be used as the corrected area of ​​the partial metal layer in the non-functional area, that is, the hole area of ​​the drilling hole set in the partial metal layer.

[0097] It is understandable that the above is only an exemplary method for determining the correction parameters of the part to be reduced and the part to be increased. The correction parameters of the part to be reduced and the part to be increased can also be determined in other ways. For example, a metal pad with a volume difference absolute value volume can be set in the non-functional area of ​​the part to be increased, and no specific limitation is made here.

[0098] S38. Determine the laying parameters of each metal layer in each sub-region according to the area of ​​each sub-region, the original design parameters and the modified parameters.

[0099] The technical solution of the embodiment of the present invention is to divide the circuit board in the sub-area into a first part and a second part through the middle plane, and determine the first metal volume of the first part and the second metal volume of the second part in the sub-area according to the original design parameters. If the absolute value of the difference between the first metal volume and the second metal volume is less than or equal to the first preset difference, it means that the difference between the metal volume of the first part and the second part is small, the stress distribution of the first part and the second part is relatively balanced, and the effect on the warping of the circuit board is small, and there is no need to correct the design parameters of the metal layer. If the absolute value of the difference between the first metal volume and the second metal volume is greater than the first preset difference, it means that the difference between the metal volume of the first part and the second part is large, and the part of the circuit board corresponding to the larger of the first metal volume and the second metal volume is determined as the part to be reduced and adjusted, and the part of the circuit board corresponding to the smaller of the first metal volume and the second metal volume is determined as the part to be increased and adjusted, and then according to the first metal volume and the second metal volume, the correction parameters of the part to be reduced or the part to be increased are determined, so as to correct the design parameters of the part to be increased or the part to be reduced, reduce the difference between the metal volume of the first part and the second part, balance the stress distribution of the first part and the second part, reduce the risk of warping of the circuit board, and improve the flatness of the circuit board.

[0100] In an optional embodiment, the embodiment of the present invention describes the situation of determining the laying parameters of each metal layer in each sub-region according to the area of ​​each sub-region, the original design parameters and the modified parameters. Figure 4A flowchart of another circuit board design method provided by an embodiment of the present invention is shown in FIG. Figure 4 As shown, the design method of the circuit board includes:

[0101] S41. Obtain original design parameters of the circuit board.

[0102] The original design parameters at least include the design size of the circuit board.

[0103] S42: Divide a surface of one side of the circuit board into at least two sub-areas according to original design parameters.

[0104] The area of ​​the sub-region is smaller than the design area of ​​the circuit board.

[0105] S43. Determine the middle plane of the circuit board according to the original design parameters.

[0106] The original design parameters also include the design thickness of the circuit board.

[0107] S44. Determine, according to the middle plane and the original design parameters, correction parameters of at least part of the metal layer in the sub-region.

[0108] The correction parameters include correction thickness and / or correction area.

[0109] S45. Determine the metal volume and total volume of the sub-region according to the area of ​​the sub-region, the original design parameters and the modified parameters.

[0110] The metal volume of the zone is the total metal volume of the sub-zone, and the total volume of the zone is the total volume of the sub-zone.

[0111] Specifically, the metal volume of the sub-region can be determined according to the original thickness, modified thickness, setting area and modified area of ​​each metal layer in the sub-region. For example, if only one metal pad is set in the metal layer located on the surface of the circuit board in the first part of the sub-region, the thickness of the metal layer is the modified thickness, the area of ​​the metal layer is the modified area, the product of the original thickness of the metal layer and the setting area is taken as the original volume, the product of the modified thickness of the metal pad of the metal layer and the modified area is taken as the modified volume, and the sum of the original volume and the modified volume is taken as the metal volume of the metal layer. Since no metal pad or drilling hole is set in the remaining layers, the modified thickness and the modified area of ​​the remaining metal layers are both zero, and the product of the original thickness and the setting area of ​​each metal layer can be taken as the metal volume of each metal layer, and then the calculated metal volumes of each metal layer are summed, and the summed value is the total metal volume of the sub-region. The product of the area of ​​the sub-region and the design thickness of the circuit board can be taken as the total volume of the sub-region.

[0112] In an optional embodiment, the metal volume and total volume of the sub-region are determined based on the area of ​​the sub-region, the original design parameters and the correction parameters, including determining the metal volume of the sub-region based on the original design parameters and the correction coefficient; determining the total volume of the sub-region based on the area of ​​the sub-region and the original design parameters.

[0113] Specifically, the original volume of each metal layer in the sub-region can be calculated according to the original thickness and setting area of ​​each metal layer in the original design parameters, and the sum of the original volumes of each metal layer is used as the original metal volume of the sub-region, and then the increased or reduced metal volume of the sub-region is calculated according to the correction parameters, and then the sum of the original metal volume and the increased metal volume is used as the district metal volume of the sub-region, or the difference between the original metal volume and the reduced metal volume is used as the district metal volume of the sub-region. The product of the design thickness of the circuit board in the original design parameters and the area of ​​the sub-region is used as the total district volume of the sub-region.

[0114] S46. Determine the metal volume ratio of the sub-region according to the metal volume of the sub-region and the total volume of the region.

[0115] The metal volume ratio of the sub-region refers to the ratio of the total volume of the metal in the sub-region to the total volume of the sub-region after the metal layer of the sub-region is corrected.

[0116] Specifically, the ratio of the metal volume of the zone to the total volume of the zone is taken as the metal volume ratio.

[0117] S47, determining whether the absolute value of the ratio difference of the metal volume ratios corresponding to two adjacent sub-regions is less than or equal to a second preset difference; if so, executing S48; if not, executing S49.

[0118] The second preset difference can be set according to actual needs. For example, the second preset difference is 30%, and can be other values, which are not specifically limited here.

[0119] Specifically, the difference in the metal volume ratios corresponding to two adjacent sub-regions is calculated, and the absolute value of the difference is taken as the absolute value of the ratio difference. If the absolute value of the ratio difference of the metal volume ratios corresponding to the two adjacent sub-regions is less than or equal to the second preset difference, it means that the difference in the metal volume ratios between the two sub-regions is small, the stress distribution between the two sub-regions is relatively balanced, and the risk of warping of the circuit board in these two sub-regions is low, and there is no need to further adjust the metal layers of the two sub-regions. If the absolute value of the ratio difference of the metal volume ratios corresponding to the two adjacent sub-regions is greater than the second preset difference, it means that the difference in the metal volume ratios between the two sub-regions is large, the stress distribution difference between the two sub-regions is large, and the risk of warping of the circuit board in these two sub-regions is high. It is necessary to further adjust the metal layers of the two sub-regions to reduce the risk of warping of the circuit board between the two sub-regions and improve the flatness of the circuit board.

[0120] S48. Determine the laying parameters of each metal layer in the sub-area according to the original design parameters and the modified parameters of each metal layer in the sub-area.

[0121] The laying parameters include laying thickness and / or laying area.

[0122] Specifically, for a metal layer whose correction parameter is 0, the laying thickness of the metal layer in the laying parameters is the original thickness, and the laying area is the set area. For a metal layer whose correction thickness in the correction parameters is not zero and whose correction area is zero, the laying thickness of the metal layer in the laying parameters is the sum of the original thickness and the corrected thickness, wherein the corrected thickness can be a positive number or a negative number. When the corrected thickness is a positive number, it means that the thickness of the metal layer needs to be increased, and when the corrected thickness is a negative number, it means that the thickness of the metal layer needs to be reduced. The laying area of ​​the metal layer in the laying parameters is the sum of the set area and the correction area, wherein the corrected area can be a positive number or a negative number. When the corrected thickness is a positive number, it means that the setting area of ​​the metal layer needs to be increased, and when the corrected thickness is a negative number, it means that the setting area of ​​the metal layer needs to be reduced.

[0123] S49, determining the adjusted metal volume ratio of the sub-region according to the absolute value of the ratio difference and the second preset difference.

[0124] Specifically, the difference between the absolute value of the ratio difference and the second preset difference is used as the adjusted metal volume ratio of the sub-region, so that the metal volume of the sub-region can be adjusted according to the adjusted metal volume ratio to balance the metal volume of the two adjacent sub-regions, reduce the stress difference between the two adjacent sub-regions, and improve the flatness of the circuit board.

[0125] S50: Determine the sub-region with a larger metal volume ratio among two adjacent sub-regions as the sub-region to be reduced.

[0126] Specifically, a sub-region with a larger metal volume ratio has a larger stress, and this sub-region can be determined as a sub-region to be reduced, so that the metal volume of the sub-region to be reduced can be adjusted later.

[0127] S51. Determine the metal reduction volume of the sub-region to be reduced according to the adjusted metal volume ratio and the total volume of the sub-region to be reduced.

[0128] The metal reduction volume of the sub-region to be reduced represents the metal volume that needs to be reduced in the sub-region to be reduced.

[0129] Specifically, the product of the adjusted metal volume ratio and the total volume of the zone is used as the metal reduction volume of the sub-region to be reduced, so that after the metal volume in the sub-region to be reduced is adjusted according to the metal reduction volume, the difference between the metal volume ratios of two adjacent sub-regions is less than the second preset difference, so as to balance the stress of the two adjacent sub-regions, reduce the risk of warping of the circuit board, and improve the flatness of the circuit board.

[0130] S52. Determine the number and size of holes to be dug in at least part of the metal layer in the sub-region to be reduced according to the metal reduction volume.

[0131] The laying parameters also include the number of holes and the size of holes. The number of holes indicates the number of holes set, and the size of holes includes the thickness and area of ​​the holes.

[0132] Specifically, holes with reduced metal volume can be set in the sub-region to be reduced, and the holes are all set in the metal layer region that does not affect the electrical function of the circuit board to ensure the normal operation of the circuit board. In addition, holes with the same volume can be set in the first part and the second part of the sub-region to be reduced, respectively, and the sum of the hole volumes of the first part and the second part is the reduced metal volume. On the premise of balancing the metal volume ratio between the sub-regions, the metal volume distribution of the first part and the second part inside the sub-region is further balanced, the stress distribution in the circuit board is balanced, the risk of warping of the circuit board is reduced, and the flatness of the circuit board is improved.

[0133] The technical solution of the embodiment of the present invention determines the metal volume and total volume of the sub-region according to the area, original design parameters and correction parameters of the sub-region to determine the metal volume ratio of the sub-region. If the absolute value of the ratio difference of the metal volume ratios corresponding to two adjacent sub-regions is less than or equal to the second preset difference, it means that the difference in the metal volume ratios of the two adjacent sub-regions is small, that is, the stress difference between the two adjacent sub-regions is small, and there is no need to further adjust the metal layer. The laying parameters of each metal layer in the sub-region can be determined according to the original design parameters and correction parameters of each metal layer in the sub-region. If the absolute value of the ratio difference of the metal volume ratios corresponding to the two adjacent sub-regions is greater than the second preset difference, it means that the difference in the metal volume ratios between the two adjacent sub-regions is large. The metal layer parameters in the two adjacent sub-regions can be adjusted according to the metal volume ratios of the two adjacent sub-regions and the second preset difference to determine the final metal layer laying parameters, so as to balance the stress distribution between the sub-regions in the circuit board, reduce the risk of circuit board bending and warping caused by uneven stress, and improve the flatness of the circuit board.

[0134] Based on the same inventive concept, an embodiment of the present invention further provides a circuit board, which is designed using the circuit board design method provided by any embodiment of the present invention and has the same beneficial effects as the design method. The similarities can be referred to above and will not be repeated here.

[0135] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A circuit board design method, characterized in that: include: Obtaining original design parameters of the circuit board; The original design parameters at least include the design dimensions of the circuit board; According to the original design parameters, a surface of one side of the circuit board is divided into at least two sub-areas; the area of ​​the sub-areas is smaller than the design area of ​​the circuit board; The laying parameters of each metal layer in the sub-area are determined according to the original design parameters and the area of ​​each sub-area; the original design parameters also include the original thickness and setting area of ​​each metal layer in each sub-area; the laying parameters include laying thickness and / or laying area.

2. The design method according to claim 1, characterized in that: Determining the laying parameters of each metal layer in each sub-region according to the original design parameters and the area of ​​each sub-region includes: Determining the middle plane of the circuit board according to the original design parameters; the design dimensions include the design thickness; Determine, according to the intermediate plane and the original design parameters, correction parameters of at least part of the metal layer in the sub-region; the correction parameters include a correction thickness and / or a correction area; The laying parameters of each metal layer in each sub-region are determined according to the area of ​​each sub-region, the original design parameters and the modified parameters.

3. The design method according to claim 2, characterized in that: Determining, according to the intermediate plane and the original design parameters, correction parameters of at least part of the metal layer in the sub-region, comprising: Determine, according to the middle plane and the original design parameters, a first metal volume of a first part and a second metal volume of a second part of the sub-region; the first part is a part of the circuit board located on a first side of the middle plane, and the second part is a part of the circuit board located on a second side of the middle plane; in a thickness direction of the circuit board, the first side and the second side are arranged opposite to each other; A correction parameter of at least a portion of the metal layer in the sub-region is determined according to the first metal volume and the second metal volume.

4. The design method according to claim 3, characterized in that: Determining a first metal volume of a first part and a second metal volume of a second part in the sub-region according to the middle plane and the original design parameters comprises: Determine, according to the middle plane and the original design parameters, each first metal sub-volume in each metal layer in the first portion and each second metal sub-volume in each metal layer in the second portion; determining the first metal volume according to each of the first metal sub-volumes in each of the metal layers in the first portion; The second metal volume is determined according to each of the second metal sub-volumes in each of the metal layers in the second portion.

5. The design method according to claim 3, characterized in that: Determining correction parameters of at least part of the metal layer in the sub-region according to the first metal volume and the second metal volume includes: Determining whether an absolute value of a difference between the first metal volume and the second metal volume is greater than a first preset difference; If yes, the portion of the circuit board corresponding to the larger of the first metal volume and the second metal volume is determined as the portion to be reduced and adjusted, and the portion of the circuit board corresponding to the smaller of the first metal volume and the second metal volume is determined as the portion to be increased and adjusted; The correction parameter of the portion to be reduced or the portion to be increased is determined according to the first metal volume and the second metal volume.

6. The design method according to claim 5, characterized in that: Determining the correction parameter of the portion to be reduced or the portion to be increased according to the first metal volume and the second metal volume includes: Calculating an absolute value of a volume difference between the first metal volume and the second metal volume; The corrected thickness of the portion to be increased is determined according to the absolute value of the volume difference and the area of ​​the sub-region; or the corrected area of ​​the portion to be decreased is determined according to the absolute value of the volume difference and the thickness of each metal layer in the sub-region.

7. The design method according to claim 2, characterized in that: Determining the laying parameters of each metal layer in each sub-region according to the area of ​​each sub-region, the original design parameter and the modified parameter, including: Determine the metal volume and total volume of the sub-region according to the area of ​​the sub-region, the original design parameters and the modified parameters; the metal volume of the sub-region is the total metal volume of the sub-region, and the total volume of the sub-region is the total volume of the sub-region; Determining a metal volume ratio of the sub-region according to the metal volume of the sub-region and the total volume of the region; Determine whether the absolute value of the ratio difference of the metal volume ratios corresponding to two adjacent sub-regions is less than or equal to a second preset difference; If so, the laying parameters of each metal layer in the sub-area are determined according to the original design parameters and the modified parameters of each metal layer in the sub-area.

8. The design method according to claim 7, characterized in that: If the absolute value of the ratio difference of the metal volume ratios corresponding to two adjacent sub-regions is greater than the second preset difference; then determining the adjusted metal volume ratio of the sub-region according to the absolute value of the ratio difference and the second preset difference; Determine the sub-region having the larger metal volume ratio in two adjacent sub-regions as the sub-region to be reduced; Determining the metal reduction volume of the sub-region to be reduced according to the adjusted metal volume ratio and the total volume of the sub-region to be reduced; According to the metal reduction volume, the number and size of holes to be dug in at least part of the metal layer in the sub-area to be reduced are determined; the laying parameters also include the number and size of holes to be dug.

9. The design method according to claim 7, characterized in that: Determining the metal volume and the total volume of the sub-region according to the area of ​​the sub-region, the original design parameter and the modified parameter, including: Determining the metal volume of the sub-region according to the original design parameters and the correction coefficient; The total volume of the sub-region is determined according to the area of ​​the sub-region and the original design parameters.

10. A circuit board, characterized in that: The circuit board is designed by using the circuit board design method according to any one of claims 1 to 9.

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