Exposure method for maintaining high-precision alignment of patterns on surface A and surface B of substrate

Abstract

The invention relates to PCB (Printed Circuit Board) manufacturing, in particular to an exposure method for keeping high-precision alignment of patterns on an A surface and a B surface of a substrate, which comprises the following steps of: grabbing the position of a positioning hole on the A surface, reversely calculating the accurate position of the positioning hole in the pattern according to a mode of centering and aligning the A surface, and exposing the A surface; grabbing the position of a B surface positioning hole, and exposing the B surface according to the position of the B surface positioning hole; according to the technical scheme provided by the invention, the defect that patterns on the AB surface of the substrate are difficult to achieve relatively high alignment precision in the prior art can be effectively overcome.

Description

Technical Field

[0001] The invention relates to PCB manufacturing, and in particular to an exposure method for maintaining high-precision alignment of AB surface graphics on a substrate. Background Art

[0002] In the actual manufacturing process of PCB, for substrates with holes on four sides but not target holes (the target holes in the PCB process are opened according to the target hole layer, the relative position between the target hole and the exposure pattern is accurate, and the upstream and downstream links are positioned according to the target holes, so the overlay accuracy of the final product can meet the requirements), when the A side (front side) and B side (back side) patterns have a high alignment accuracy (±7μm), the inner layer method is generally used to process it. The precise camera position of the laser pattern in the pattern is reversely calculated according to the center alignment method of the A side. While exposing the A side, the laser pattern is used to target the B side, the position of the B side laser pattern is captured, and the B side is exposed according to the position of the B side laser pattern (the specific process is as follows Figure 2 shown).

[0003] The above technical solution has the following main disadvantages: 1) It is necessary to use a color-developing dry film or ink; 2) There should be a margin of about 3mm on the edge of the substrate, otherwise the laser pattern will invade the customer pattern; 3) The edge clarity of the laser pattern on the B side will affect the alignment accuracy. If the alignment accuracy of the hole is ±5μm, then the alignment accuracy of the laser pattern can only reach ±10μm. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides an exposure method for maintaining high-precision alignment of the AB surface graphics of the substrate, which can effectively overcome the defect of the prior art that it is difficult to achieve high alignment accuracy of the AB surface graphics of the substrate.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] An exposure method that maintains high-precision alignment of the A and B surfaces of the substrate, captures the position of the positioning hole on the A surface, reversely calculates the precise position of the positioning hole in the pattern in accordance with the center alignment of the A surface, and exposes the A surface;

[0009] Grasp the position of the B-side positioning hole and expose the B-side according to the position of the B-side positioning hole.

[0010] Preferably, the step of grasping the position of the positioning hole on the A surface, reversely calculating the precise position of the positioning hole in the pattern in a manner of centering the A surface, and exposing the A surface comprises:

[0011] S1, surface A calculates exposure matrix MA in a non-aligned manner;

[0012] S2, taking the lower left corner target as the reference point, calculate the position of the reference point on the substrate;

[0013] S3, calculating the positions of other targets on the substrate according to the relative positions between other targets and the reference points;

[0014] S4, calculating the displacement of each piece relative to the origin of the swing piece according to the swing piece template;

[0015] S5. Calculate the theoretical position WCenter1 of the first target of each target on the A surface in the world coordinate system according to the swing sheet template and the table parameters;

[0016] S6, grab the actual position RWCenter1 of the first target of all targets on surface A;

[0017] S7. Expose surface A using exposure matrix MA.

[0018] Preferably, the step of grasping the position of the positioning hole of the B surface and exposing the B surface according to the position of the positioning hole of the B surface comprises:

[0019] S8, calculating the position SCAMCenter of each target in the camera image after expansion and contraction;

[0020] S9, calculating the second target theoretical position WCenter2 of each target on the B surface in the world coordinate system, and the transformation matrix WCenterMartrix from the position SCAMCenter of each target in the camera image after expansion and contraction to the second target theoretical position WCenter2 of each target in the world coordinate system;

[0021] S10, grab the actual position RWCenter2 of the second target of all targets on surface B;

[0022] S11, calculating the transformation matrix M from the second target theoretical position WCenter2 of each target on the B surface in the world coordinate system to the second target actual position RWCenter2 of each target;

[0023] S12, determining whether it is a fixed expansion and contraction, if it is a fixed expansion and contraction, eliminating the expansion and contraction in the transformation matrix M, and superimposing the transformation matrix M on the transformation matrix WCenterMartrix as the exposure matrix MB, otherwise directly superimposing the transformation matrix M on the transformation matrix WCenterMartrix as the exposure matrix MB;

[0024] S13. Expose surface B using exposure matrix MB.

[0025] (III) Beneficial effects

[0026] Compared with the prior art, the exposure method for maintaining high-precision alignment of the AB surface patterns of the substrate provided by the present invention has the following beneficial effects:

[0027] 1) No need to use color-developing dry film or ink;

[0028] 2) No margin is required on the edge of the substrate;

[0029] 3) The alignment accuracy can be consistent with the outer layer;

[0030] 4) For substrates without holes, only rough drilling is required to achieve precise alignment of the AB surface graphics. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 It is a schematic diagram of the process of the present invention;

[0033] Figure 2 The figure is a schematic diagram of the process of exposing the AB surface patterns of the substrate in the prior art. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] An exposure method that maintains high-precision alignment of the A and B surfaces of the substrate, captures the position of the positioning hole on the A surface, reversely calculates the precise position of the positioning hole in the pattern in accordance with the center alignment of the A surface, and exposes the A surface;

[0036] Grasp the position of the B-side positioning hole and expose the B-side according to the position of the B-side positioning hole.

[0037] like Figure 1 As shown, the position of the positioning hole on the A side is captured, the precise position of the positioning hole in the pattern is reversely calculated by centering the A side, and the A side is exposed, including:

[0038] S1, surface A calculates exposure matrix MA in a non-aligned manner;

[0039] S2, taking the lower left corner target as the reference point, calculate the position of the reference point on the substrate;

[0040] S3, calculating the positions of other targets on the substrate according to the relative positions between other targets and the reference points;

[0041] S4, calculating the displacement of each piece relative to the origin of the swing piece according to the swing piece template;

[0042] S5. Calculate the theoretical position WCenter1 of the first target of each target on the A surface in the world coordinate system according to the swing sheet template and the table parameters;

[0043] S6, grab the actual position RWCenter1 of the first target of all targets on surface A;

[0044] S7. Expose surface A using exposure matrix MA.

[0045] like Figure 1 As shown, the position of the positioning hole of the B surface is grasped, and the B surface is exposed according to the position of the positioning hole of the B surface, including:

[0046] S8, calculating the position SCAMCenter of each target in the camera image after expansion and contraction;

[0047] S9, calculating the second target theoretical position WCenter2 of each target on the B surface in the world coordinate system, and the transformation matrix WCenterMartrix from the position SCAMCenter of each target in the camera image after expansion and contraction to the second target theoretical position WCenter2 of each target in the world coordinate system;

[0048] S10, grab the actual position RWCenter2 of the second target of all targets on surface B;

[0049] S11, calculating the transformation matrix M from the second target theoretical position WCenter2 of each target on the B surface in the world coordinate system to the second target actual position RWCenter2 of each target;

[0050] S12, determining whether it is a fixed expansion and contraction, if it is a fixed expansion and contraction, eliminating the expansion and contraction in the transformation matrix M, and superimposing the transformation matrix M on the transformation matrix WCenterMartrix as the exposure matrix MB, otherwise directly superimposing the transformation matrix M on the transformation matrix WCenterMartrix as the exposure matrix MB;

[0051] S13. Expose surface B using exposure matrix MB.

[0052] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An exposure method for maintaining high-precision alignment of the AB surface patterns of a substrate, characterized in that: Grab the position of the positioning hole on the A side, reversely calculate the precise position of the positioning hole in the pattern by centering the A side, and expose the A side; Grasp the position of the B-side positioning hole and expose the B-side according to the position of the B-side positioning hole.

2. The exposure method for maintaining high-precision alignment of the AB surface patterns of the substrate according to claim 1, characterized in that: The method of grabbing the position of the positioning hole on the A surface, reversely calculating the precise position of the positioning hole in the pattern in a manner of centering the A surface, and exposing the A surface includes: S1, surface A calculates exposure matrix MA in a non-aligned manner; S2, taking the lower left corner target as the reference point, calculate the position of the reference point on the substrate; S3, calculating the positions of other targets on the substrate according to the relative positions between other targets and the reference points; S4, calculating the displacement of each piece relative to the origin of the swing piece according to the swing piece template; S5. Calculate the theoretical position WCenter1 of the first target of each target on the A surface in the world coordinate system according to the swing sheet template and the table parameters; S6, grab the actual position RWCenter1 of the first target of all targets on surface A; S7. Expose surface A using exposure matrix MA.

3. The exposure method for maintaining high-precision alignment of the AB surface patterns of the substrate according to claim 2, characterized in that: The step of grasping the position of the positioning hole of the B surface and exposing the B surface according to the position of the positioning hole of the B surface comprises: S8, calculating the position SCAMCenter of each target in the camera image after expansion and contraction; S9, calculating the second target theoretical position WCenter2 of each target on the B surface in the world coordinate system, and the transformation matrix WCenterMartrix from the position SCAMCenter of each target in the camera image after expansion and contraction to the second target theoretical position WCenter2 of each target in the world coordinate system; S10, grab the actual position RWCenter2 of the second target of all targets on surface B; S11, calculating the transformation matrix M from the second target theoretical position WCenter2 of each target on the B surface in the world coordinate system to the second target actual position RWCenter2 of each target; S12, determining whether it is a fixed expansion and contraction, if it is a fixed expansion and contraction, eliminating the expansion and contraction in the transformation matrix M, and superimposing the transformation matrix M on the transformation matrix WCenterMartrix as the exposure matrix MB, otherwise directly superimposing the transformation matrix M on the transformation matrix WCenterMartrix as the exposure matrix MB; S13. Expose surface B using exposure matrix MB.

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