A method for manufacturing a thin high-precision back-attached circuit board

Abstract

The application discloses a kind of production methods of thin high-precision back attached circuit board, process includes: dispensing black resin ink, respectively making to be guided gas board, guide ink board, to be plugged hole board and blocking point screen printing plate, and from bottom to top sequentially laminating above-mentioned board layer, form plug hole processing structure;Plug hole processing is carried out to to be plugged hole board, and then sequentially baking and polishing, form plug hole board;Films are made and attached to plug hole board surface, and optical scanning is used to check plug hole yield rate;Again, after process processing, form thin high-precision back attached circuit board;By dispensing black resin ink, meet the light shielding requirement of plug hole and circuit board application, solve the problem of circuit board application display light leakage;By designing plug hole structure in vacuum environment, prevent plug hole processing oil, convexity, etc., overall structure realizes high-precision plug hole processing, improves the processing quality of circuit board with higher linear density and thinner thickness, prevent board surface deformation, light transmission, etc.

Description

Technical Field

[0001] The present invention relates to the field of circuit board manufacturing, and in particular to a method for manufacturing a thin, high-precision back-attached circuit board. Background Art

[0002] For a type of back-attached circuit board used in high-precision display screens, the wiring is usually required to be high-density and thin, so the number of circuit layers is generally double or multi-layer, and the back-attached circuit board has high requirements for the light-shielding performance of the entire board to avoid light leakage in the application display due to light transmission of the circuit board.

[0003] In the prior art, blind vias are usually made for the above-mentioned back-attached circuit boards to form high-density interconnections between multi-layer circuits. However, the production of blind vias in multi-layer circuits is relatively difficult, and the board surface needs to be polished flat after the blind vias are electroplated and filled. The blind vias are solid copper holes, which require greater polishing pressure or more polishing times. The thin board body is prone to deformation, over-polishing, and even tearing.

[0004] Therefore, in order to solve the problems raised by the above background technology, it is necessary to provide a method for manufacturing a thin and high-precision back-attached circuit board. Summary of the Invention

[0005] The present invention aims to solve the problem of the prior art that back-attached circuit boards require a thin board body and high wiring density, and proposes a method for manufacturing a thin, high-precision back-attached circuit board. The manufacturing method comprises the following steps:

[0006] S10: taking resin ink and mixing it to form black resin ink;

[0007] S20: Take a rigid plate and make a hole to be plugged to form a hole-to-be-plugged plate;

[0008] Taking a screen, making a through-window pattern corresponding to the hole to be plugged, forming a blocking point screen;

[0009] Manufacturing an ink guide plate having an ink guide plate adsorption hole and an ink guide plate hole to be plugged, wherein the ink guide plate hole to be plugged corresponds to the hole to be plugged;

[0010] Making a support plate with the same height as the ink guide plate, wherein the support plate is a frame provided at the edge area of ​​the plate to be plugged;

[0011] Producing an air guide plate with air guide plate adsorption holes, wherein the air guide plate adsorption holes correspond to the ink guide plate adsorption holes;

[0012] The air guide plate, the ink guide plate, the plate to be plugged and the dot screen are stacked in sequence from bottom to top, and the ink guide plate is arranged in the frame to form a plugging processing structure;

[0013] S30: using the hole processing structure to process the hole plate, and then baking and polishing in sequence to form a hole plate;

[0014] S40: making a film, the light transmission area of which corresponds to the hole to be processed, attaching the film to the surface of the hole plate to form a detection plate, and using optical scanning to check the hole yield rate;

[0015] After further processing, the thin high-precision back-attached circuit board is formed.

[0016] Further, the preparation is to take carbon black powder, add solvent, stir uniformly to form carbon black additive, add the carbon black additive to the resin ink, stir uniformly to form the black resin ink.

[0017] Further, the solvent is propylene glycol methyl ether, ethylene glycol tert-butyl ether, diethyl carbonate or propylene glycol methyl ether acetate.

[0018] Further, the mass fraction of the carbon black powder in the black resin ink is 5% to 15%, and the mass fraction of the solvent in the black resin ink is 1% to 5%.

[0019] Further, the ink guide plate adsorption hole and the air guide plate adsorption hole are both copper-free holes.

[0020] Further, the hole processing is vacuum hole processing of the hole plate to be processed using the hole processing structure.

[0021] Further, the size of the hole plate to be processed is pre-designed to be larger on one side, and the pre-designed size is greater than or equal to the frame width of the frame.

[0022] Further, the baking is segmented baking, which is baking at 120°C for 10 minutes, baking at 130°C for 10 minutes, and baking at 140°C for 30 minutes in sequence.

[0023] Further, the polishing is single polishing.

[0024] Further, the use of optical scanning to check the hole yield rate includes the steps of: designing computer graphics data containing only the hole to be processed, using automatic optical detection equipment to scan the detection plate to form a detection pattern, comparing the computer graphics data with the detection pattern, and checking the hole yield rate.

[0025] The technical scheme of the present application satisfies the light shielding requirement of the hole and the circuit board application by adjusting the black resin ink, solves the application display light leakage problem caused by the light transmission of the circuit board in the prior art; by designing the hole structure, the hole in the vacuum environment is realized, and the hole plate to be fixed is accurately fixed by the table, and then the hole is printed by the blocking point screen wire, which can effectively prevent the hole processing from oiling, the protrusion from being too high, and the subsequent polishing from being difficult, etc.; by designing the laminated comparison structure of the film pattern and the hole, the optical scanning is carried out by using the AOI equipment, the reverse pattern comparison is carried out, the hole inspection efficiency of the circuit board is improved, and the circuit board processing effect is accelerated; the overall structure realizes the high-precision hole processing, has high one-time processing qualification rate; the overall processing process is convenient to operate, effectively improves the processing quality of the circuit board with high line density and thin thickness, prevents the board surface from deforming, and prevents the light transmission during application. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the drawings shown.

[0027] Figure 1 It is a process flow diagram of the embodiment of the present application.

[0028] Figure 2 It is a cross-sectional structure diagram of the hole processing structure of the embodiment of the present application.

[0029] Figure 3 It is a schematic diagram of optical scanning of the hole plate of the embodiment of the present application.

[0030] Figure 4 It is a cross-sectional structure diagram of the thin high-precision back-attached circuit board of the embodiment of the present application.

[0031] Explanation of the drawings:

[0032]

[0033] The implementation, functional characteristics and advantages of the present application will be further described with reference to the drawings. DETAILED DESCRIPTION

[0034] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort are within the protection scope of the present application.

[0035] It should be noted that all the direction indications (such as up, down, left, right, front, back, inside, outside, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the direction indications also change accordingly.

[0036] In addition, the descriptions such as “first”, “second” and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined with “first”, “second” can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of “plurality” is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0037] In addition, the technical solutions of each embodiment of the present application can be combined with each other, but it must be based on the realization of a person of ordinary skill in the art, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope of the present application.

[0038] Please refer to Figure 1 , Figure 1 for the process flowchart of the embodiment of the present application. Figure 2 for the cross-sectional structure diagram of the plug hole processing structure of the embodiment of the present application.

[0039] The manufacturing process of the embodiment of the present application includes the implementation of each step process in Figure 1 The following will make further step-by-step description of each step process in Figure 1 .

[0040] Step S10:

[0041] The resin ink is taken to prepare the black resin ink 100; in the embodiment, the carbon black powder is added into the solvent and stirred uniformly to form a carbon black additive, which is added into the resin ink and stirred uniformly to form the black resin ink 100; the carbon black powder can interact with the resin ink and the solvent to form the black resin ink 100 which is uniformly mixed and has good slow evaporation, high temperature resistance and light shielding property, and can meet the requirements of the filling performance of the black resin ink 100 in the subsequent processes such as silk printing and baking, and the light shielding requirement of the black resin ink 100 in the optical scanning in the subsequent processes, and also provides a material basis for the hole filling in the subsequent processes.

[0042] In the embodiment, the solvent is propylene glycol methyl ether, ethylene glycol tert-butyl ether, diethyl carbonate or propylene glycol methyl ether acetate, which has good solubility to the resin, avoids the problem that the viscosity of the black resin ink 100 is too large due to the direct addition of the carbon black powder for color matching, and is not conducive to the subsequent silk printing and filling, and the solvent has slow evaporation and high temperature evaporation, so that the solvent components are not easy to evaporate quickly during the baking process in the subsequent processes, the viscosity of the black resin ink 100 is not easy to change due to heating, and the problem of silk printing difficulty is avoided, further, the high temperature evaporation can ensure that the solvent can be completely evaporated after baking, so as not to affect the filling effect of the black resin ink 100, and the applicability of the black resin ink 100 is improved.

[0043] In the embodiment, the mass fraction of the carbon black powder in the black resin ink 100 is 5% to 15%, and the common white resin ink is matched to the black resin ink 100 by using the carbon black powder, which can prepare for the light shielding of the subsequent AOI optical scanning, and ensure the light shielding of the board body when the circuit board is applied, so as to avoid the problem of display screen light leakage; the mass fraction of the solvent in the black resin ink 100 is 1% to 5%, and the amount of the solvent is not easy to be too much, so as to avoid the problems that the viscosity of the black resin ink 100 is too low to fill the hole, and the solvent is not easy to evaporate when the subsequent baking is performed.

[0044] Step S20:

[0045] The rigid plate is taken to prepare the to-be-filled hole 2010 to form the to-be-filled hole plate 200; the to-be-filled hole is a copper through hole which can communicate the upper and lower two layers of lines, and also provides an ink flow channel for filling the black resin ink in the subsequent process.

[0046] In an embodiment, the size of the to-be-plugged hole plate 200 is unilaterally pre-enlarged, and the pre-enlarged size is greater than or equal to the frame width of the frame; that is, the "invalid area" size of the edge of the to-be-plugged hole plate 200 is enlarged, so that the black resin ink 100 is not easy to flow out of the outer edge of the plate surface of the to-be-plugged hole plate 200 when being screen printed to the edge of the to-be-plugged hole plate 200, and sufficient size is given to the support plate to prevent the problem of oil gathering or unevenness of the to-be-plugged hole.

[0047] Taking a screen plate, a window pattern 3010 corresponding to the to-be-plugged hole 2010 is made to form a blocking point screen plate 300; the pattern area of the blocking point screen plate 300 is the area of the screen printed black resin ink 100, which corresponds to the to-be-plugged hole 2010, and the remaining blocking point area is the area of the non-leakage black resin ink 100. The to-be-plugged hole is filled with black resin ink 100 in the manner of using the blocking point screen plate 300, rather than in the manner of directly using a squeegee or an aluminum sheet or a copper sheet tool to plug the hole, which has the beneficial effect of effectively avoiding the problems of oil oozing and protrusion of the to-be-plugged hole 2010. Further, it also provides a plate surface that is easy to polish for the subsequent polishing process, avoiding the problem of deformation of the plate body caused by multiple polishing due to oil oozing or protrusion of the plate surface.

[0048] A guide ink plate 400 with a guide ink plate to-be-plugged hole 4010 and a guide ink plate adsorption hole 4020 is made, and the guide ink plate adsorption hole 4020 provides a structural basis for the subsequent formation of an adsorption channel. Further, the guide ink plate to-be-plugged hole 4010 corresponds to the to-be-plugged hole 2010 to form a filling channel, which provides a resin flow channel for the subsequent plugging process using black resin ink 100.

[0049] A support plate 500 with the same height as the guide ink plate 400 is made, and the support plate 500 is a frame arranged at the edge area of the to-be-plugged hole plate 200. The to-be-plugged hole plate 200 is adsorbed on the support plate 500, so that the support plate 500 forms a supporting effect on the thin plate body of the to-be-plugged hole plate 200, thereby assisting in fixing the to-be-plugged hole plate 200 and preventing the problem of slippage of the to-be-plugged hole plate 200.

[0050] A guide air plate 600 with a guide air plate adsorption hole 6020 is made, and the guide air plate adsorption hole 6020 corresponds to the guide ink plate adsorption hole 4020 to form an adsorption channel, which provides a processing basis for adsorbing and fixing the to-be-plugged hole plate 200 to the support plate 500 in the subsequent vacuumizing process in a vacuum machine.

[0051] The air guide plate 600, the ink guide plate 400, the to-be-plugged hole plate 200 and the blocking point screen plate 300 are sequentially stacked from bottom to top, the ink guide plate 400 is arranged in the frame of the support plate 500, and a hole plugging processing structure 10 is formed; a processing basis is provided for hole plugging processing in a subsequent process; by arranging the structure of the support plate 500 and the ink guide plate 400 instead of only the structure of the ink guide plate 400, on the one hand, the supportability of the to-be-plugged hole plate 200 can be improved, and on the other hand, the fixing, dismounting and other processing of the to-be-plugged hole plate 200 are facilitated.

[0052] In the embodiment, the ink guide plate adsorption hole 4020 and the air guide plate adsorption hole 6020 are both copper-free holes, the ink guide plate adsorption hole 4020 and the air guide plate adsorption hole 6020 are correspondingly connected to form an adsorption channel, the ink guide plate adsorption hole 4020 corresponds to the plate body (without hole distribution) in the to-be-plugged hole plate 200, and an adsorption force for the to-be-plugged hole plate 200 is formed, the to-be-plugged hole plate 200 is adsorbed to the plate surface in a vacuum environment, the plate surface of the to-be-plugged hole plate 200 is leveled, the to-be-plugged hole plate 200 is processed, and problems such as hole plugging leakage, plate surface oil accumulation and hole plugging failure are prevented.

[0053] In particular, the blocking point screen plate 300 is larger than the to-be-plugged hole plate 200 on one side, so that black resin ink 100 is prevented from remaining on the to-be-plugged hole plate 200 from the edge of the blocking point screen plate 300 during silk printing, causing plate surface pollution and other problems, and the air guide plate 600 is larger than the ink guide plate 400 on one side to form a stepped structure, which enhances the stability of the hole plugging processing structure 10 on the vacuum table surface when vacuum processing is performed in a vacuum machine.

[0054] Step S30:

[0055] The to-be-plugged hole plate 200 is processed by using the hole plugging processing structure 10, and then is sequentially baked and polished to form a hole plugging plate 20.

[0056] In the embodiment, the hole plugging processing is vacuum hole plugging of the to-be-plugged hole plate 200 by using the hole plugging processing structure 10, that is, an air extraction table 700 is made, the air extraction table includes an air extraction groove 7010 and a table air extraction hole 7020, the support plate 500, the ink guide plate 400 and the air guide plate 600 are fixed to the air extraction table 700 by using a pin, the area of the air extraction table 700 is larger than the area of the air guide plate 600, the hole plugging processing structure 10 is placed in a stepped structure, the black resin ink 100 is filled in a vacuum state, can be more uniformly filled in each part of the to-be-plugged hole, greatly reduces the generation of air bubbles and gaps, improves the compactness of the black resin ink 100 in the to-be-plugged hole 2010, and makes the filling precision of the to-be-plugged hole 2010 after baking and curing in a subsequent process high.

[0057] Since the carbon black powder added in the preparation of the black resin ink 100 absorbs heat quickly, the baking is divided into several steps, i.e., 120℃ for 10 minutes, 130℃ for 10 minutes, and 140℃ for 30 minutes, so that the black resin ink 100 is gradually heated, and the problem of the hole plate burst due to the too high temperature in single baking is avoided.

[0058] In the present embodiment, the polishing is single polishing. On the one hand, since the high-precision processing of the to-be-plugged hole 2010 in the present embodiment, the protruding black resin ink 100 is less, and the single polishing can polish flat. On the other hand, since the thickness of the plate body is thin, multiple polishing can easily cause the problems of deformation, over-polishing, and even tearing of the plate body.

[0059] Please refer to Figure 3 and Figure 4 , Figure 3 is a schematic view of optical scanning of the hole plate of the present embodiment, Figure 4 is a schematic view of the cross-sectional structure of the thin high-precision back-attached circuit board of the present embodiment.

[0060] Step S40:

[0061] The film 800 is prepared, the light transmission area 8010 of the film 800 corresponds to the to-be-plugged hole 2010, the film 800 is attached to the surface of the hole plate to form a detection plate, and the optical scanning is used to check the yield of the hole; and after the post-processing, the thin high-precision back-attached circuit board 30 is formed, i.e., the light transmission area 8010 of the film 800 corresponds to the to-be-plugged hole 2010, and the light shielding area 8020 shields the remaining area of the plate surface; in the present embodiment, the optical scanning is used to check the yield of the hole, and the steps include: designing computer graphics data including only the to-be-plugged hole 2010, using an automatic optical detection device to scan the detection plate to form a detection pattern, comparing the computer graphics data with the detection pattern, and checking the yield of the hole.

[0062] Because the board surface has other through holes such as plug-in holes in addition to the holes of the resin plug holes, the use of the film light transmission area 8010 pattern to match the plug hole can more evenly form a systematic optical chromatic aberration effect, prevent other patterns on the board surface from interfering or uneven board surface interference, cause excessive chromatic aberration and false inspection, and can form a more accurate pattern comparison effect, reduce color errors during scanning, and the film can be attached to the surface of the circuit board in the form of edge attachment; By setting the light intensity of the AOI optical scanning light, the scanned board surface presents a uniform black color under the best light parameter, if the plug hole of the plug hole 2010 is good, the scanned image is all black, if there is a resin plug hole, a leak plug hole, a half plug hole, the scanned image has a light transmission point; The plug hole 2010 corresponding to the light transmission point can be repaired, or the structure and plug hole processing parameters of the plug hole processing can be adjusted according to the problem type, and the plug hole problem is serious. Discard; Because the plug hole 2010 does not need to be transparent, the computer pattern data is all black pattern data, which is very simple to design and apply, and uses AOI to scan and compare, if there is a light leakage or light transmission point, it indicates that the plug hole 2010 has a leak plug hole or a plug hole problem.

[0063] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation, direct / indirect application in other related technical fields under the inventive concept of the present application, or the content of the present application specification and drawings are included in the patent protection scope of the present application.

Claims

1. A method for manufacturing a thin high-precision back-attached circuit board, comprising the following steps: S10: taking a resin ink, and blending to form a black resin ink; S20: taking a rigid plate, manufacturing a to-be-plugged hole, and forming a to-be-plugged hole plate; taking a screen, manufacturing a window pattern corresponding to the to-be-plugged hole, and forming a blocking point screen; manufacturing a guide ink plate with a guide ink plate adsorption hole and a guide ink plate to-be-plugged hole, wherein the guide ink plate to-be-plugged hole corresponds to the to-be-plugged hole of the to-be-plugged hole plate; manufacturing a support plate with a height same as that of the guide ink plate, wherein the support plate is a frame arranged at an edge region of the to-be-plugged hole plate; manufacturing a guide air plate with a guide air plate adsorption hole, wherein the guide air plate adsorption hole corresponds to the guide ink plate adsorption hole; sequentially stacking the guide air plate, the guide ink plate, the to-be-plugged hole plate, and the blocking point screen from bottom to top, wherein the guide ink plate is arranged in the frame, and a plugging processing structure is formed; S30: using the plugging processing structure to perform plugging processing on the to-be-plugged hole plate, and then sequentially baking and polishing to form a plugging plate; S40: manufacturing a film, wherein a light transmission region of the film corresponds to a plugging hole of the plugging plate, attaching the film to a surface of the plugging plate to form a detection plate, and using optical scanning to check a plugging yield; and then performing a post-process to form the thin high-precision back-attached circuit board. 2.The method of claim 1, wherein the blending comprises: taking carbon black powder, adding a solvent, and stirring uniformly to form a carbon black additive; and adding the carbon black additive into the resin ink, and stirring uniformly to form the black resin ink. 3.The method of claim 2, wherein the solvent is propylene glycol methyl ether, ethylene glycol tert-butyl ether, diethyl carbonate, or propylene glycol methyl ether acetate. 4.The method of claim 2 or 3, wherein a mass fraction of the carbon black powder in the black resin ink is 5% to 15%, and a mass fraction of the solvent in the black resin ink is 1% to 5%. 5.The method of claim 1, wherein the guide ink plate adsorption hole and the guide air plate adsorption hole are both copper-free holes. 6.The method of claim 5, wherein the plugging processing is vacuum plugging of the to-be-plugged hole plate using the plugging processing structure. 7.The method of claim 1, wherein a size of the to-be-plugged hole plate is pre-designed to be larger on a single side, and the pre-designed size is greater than or equal to a frame width of the frame. 8.The method of claim 1, wherein the baking is segmented baking, and sequentially using 120 ℃ baking for 10 minutes, 130 ℃ baking for 10 minutes, and 140 ℃ baking for 30 minutes. ​ ​ ​ ​ ​ ​ ​ ​ 9. The method of claim 1, wherein the polishing is single polishing.

10. The method of claim 1, wherein the checking the via yield using optical scanning comprises the steps of: designing computer graphic data containing only the via to be checked, scanning the test board using an automatic optical inspection device to form a test pattern, and comparing the computer graphic data with the test pattern to check the yield of the via. ​ ​ ​

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