Manufacturing method of thin high-precision back-attached circuit board

Abstract

The invention discloses a method for manufacturing a thin high-precision back-attached circuit board, which comprises the following steps of: blending black resin ink, respectively manufacturing a to-be-guided air plate, an ink guide plate, a to-be-plugged hole plate and a blocking point screen printing plate, and sequentially laminating the plate layers from bottom to top to form a plugged hole processing structure; performing hole plugging processing on the to-be-plugged hole plate, and then performing baking and polishing in sequence to form a plugged hole plate; a film is manufactured and attached to the surface of the plug hole plate, and the plug hole yield is checked through optical scanning; and the thin high-precision back-attached circuit board is formed through post-process processing. Through the blended black resin ink, the shading requirements of hole plugging and circuit board application are met, and the problem of light leakage during display of the circuit board application is solved; the hole plugging structure is designed to plug holes in a vacuum environment, the problems of oil leakage, too high protrusion and the like during hole plugging processing are solved, high-precision hole plugging processing is achieved through the overall structure, the processing quality of a circuit board with high linear density and thin thickness is improved, and the problems of board surface deformation, light transmission during application and the like are solved.

Description

Technical Field

[0001] The 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 properties of the entire board to avoid light leakage in the application display due to light transmittance of the circuit board.

[0003] In the prior art, blind holes are usually made for the above-mentioned back-attached circuit boards to form high-density interconnections between multi-layer circuits. However, it is difficult to make blind holes in multi-layer circuits, and the board surface needs to be polished and leveled after the blind holes are electroplated and filled. The blind holes are solid copper holes, which require greater polishing pressure or more polishing times. The board body is relatively thin, which can easily lead to problems such as board deformation, excessive polishing, or 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 the back-attached circuit board requires a thin board body and high wiring density, and proposes a method for manufacturing a thin and high-precision back-attached circuit board. The manufacturing method comprises the following steps: S10: taking resin ink and mixing it to form black resin ink; S20: Take a rigid plate and make a hole to be plugged to form a hole-to-be-plugged plate; Taking a screen, making a through-window pattern corresponding to the hole to be plugged, and forming a blocking point screen; Manufacturing an ink guide plate having an ink guide plate adsorption hole and an ink guide plate plugging hole, wherein the ink guide plate plugging hole corresponds to the plugging hole; Making a support plate with the same height as the ink guide plate, wherein the support plate is a frame arranged at the edge area of ​​the plate to be plugged; Making 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; The air guide plate, the ink guide plate, the plate to be plugged and the blocking point screen are stacked in sequence from bottom to top, and the ink guide plate is arranged inside the frame to form a plugging processing structure; S30: performing plugging processing on the plate to be plugged using the plugging processing structure, and then baking and polishing in sequence to form a plugged plate; S40: manufacturing a film, wherein the light-transmitting area of ​​the film corresponds to the hole to be plugged, attaching the film to the surface of the plugging plate to form a detection plate, and using optical scanning to check the plugging hole yield; After further post-processing, the thin high-precision back-attached circuit board is formed.

[0006] Furthermore, the preparation is to take carbon black powder, add it to a solvent, stir it evenly to form a carbon black additive, add the carbon black additive to the resin ink, stir it evenly to form the black resin ink.

[0007] Furthermore, the solvent is propylene glycol methyl ether, ethylene glycol tert-butyl ether, diethyl carbonate or propylene glycol methyl ether acetate.

[0008] Furthermore, 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%.

[0009] Furthermore, the ink guide plate adsorption holes and the air guide plate adsorption holes are both copper-free holes.

[0010] Furthermore, the plugging process is to use the plugging process structure to perform vacuum plugging on the plate to be plugged.

[0011] Furthermore, the size of the plate to be plugged is pre-enlarged on one side, and the pre-enlarged size is greater than or equal to the border width of the frame.

[0012] Furthermore, the baking is staged baking, which is sequentially baked at 120° C. for 10 minutes, baked at 130° C. for 10 minutes, and baked at 140° C. for 30 minutes.

[0013] Furthermore, the grinding is a single grinding.

[0014] Furthermore, the use of optical scanning to check the yield rate of the plugged holes includes the steps of: designing computer graphics data that only includes the holes to be plugged, using automatic optical inspection equipment to scan the inspection board to form a detection pattern, comparing the computer graphics data with the detection pattern, and checking the yield rate of the plugged holes.

[0015] The technical solution of the present invention meets the light-shielding requirements of plugging holes and circuit board applications by formulating black resin ink, and solves the problem of light leakage in the application display caused by the light transmittance of the circuit board in the prior art; by designing the plugging hole structure, plugging holes in a vacuum environment is realized, and the plugging hole plate is accurately fixed using a table top, and then the plugging holes are silk-screened by a blocking mesh, which can effectively prevent the problems of oil leakage and excessive protrusions during plugging hole processing, resulting in subsequent polishing difficulties; by designing a laminated comparison structure of film graphics and plugging holes, using AOI equipment for optical scanning and reverse graphic comparison, the plugging hole inspection efficiency of the circuit board is improved, and the circuit board processing is accelerated; the overall structure realizes high-precision plugging hole processing with a high one-time processing pass rate; the overall processing process is easy to operate, effectively improves the processing quality of circuit boards with high line density and thin thickness, and prevents problems such as board deformation and light transmittance during application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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 description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0017] Figure 1 It is a schematic diagram of the process flow of an embodiment of the present invention; Figure 2 A schematic cross-sectional view of a hole plugging processing structure according to an embodiment of the present invention; Figure 3 A schematic diagram of optical scanning of a plug hole plate according to an embodiment of the present invention; Figure 4 It is a schematic diagram of the cross-sectional structure of a thin high-precision back-attached circuit board according to an embodiment of the present invention.

[0018] Description of Figure Numbers:

[0019] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0021] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, inside, outside...) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0022] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0023] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0024] See also Figure 1 , Figure 1 Schematic diagram of the process flow of an embodiment of the present invention; Figure 2 It is a schematic cross-sectional structure diagram of a hole plugging processing structure according to an embodiment of the present invention.

[0025] The manufacturing process of the embodiment of the present invention includes using Figure 1 The following will implement the various steps in the process Figure 1 Each step in the process is further explained step by step.

[0026] Step S10: Take resin ink and formulate black resin ink 100; in the present embodiment, take carbon black powder, add it into solvent, stir evenly to form carbon black additive, add carbon black additive into resin ink, stir evenly to form black resin ink 100; carbon black powder can interact with resin ink and solvent to form uniformly mixed black resin ink 100, and has good slow volatility, high temperature resistance and light shielding property, and can simultaneously meet the requirements of post-processes such as silk screen printing and baking for the filling performance of black resin ink 100, and the requirements of optical scanning in post-process for the light shielding property of black resin ink 100, and also provides material basis for plugging hole filling in post-process.

[0027] In this embodiment, the solvent is propylene glycol methyl ether, ethylene glycol tert-butyl ether, diethyl carbonate or propylene glycol methyl ether acetate. On the one hand, the above four solvents have good solubility for resin, avoiding the problem of excessive viscosity of the black resin ink 100 caused by directly adding carbon black powder for color mixing, which is not conducive to the subsequent screen printing filling. On the other hand, the above solvents have slow volatility and high-temperature volatility, so that during the baking process of the subsequent process, the solvent components are not easy to evaporate quickly, avoiding the black resin ink 100 from being heated and causing a sudden change in viscosity, which leads to difficulties in screen printing. Furthermore, the high-temperature volatility can ensure that the solvent can be completely evaporated after baking is completed, thereby not affecting the effect of filling the black resin ink 100, thereby improving the applicability of the black resin ink 100.

[0028] In this embodiment, the mass fraction of carbon black powder in the black resin ink 100 is 5% to 15%. The common white resin ink is mixed with carbon black powder to prepare the black resin ink 100. On the one hand, it prepares the light-shielding property for the subsequent AOI optical scanning, and on the other hand, it ensures the light-shielding property of the circuit board during application to avoid problems such as light leakage on the display screen. The mass fraction of the solvent in the black resin ink 100 is 1% to 5%. The amount of solvent added should not be too much to avoid problems such as the black resin ink 100 having too low viscosity and being difficult to plug the holes, and too much solvent and being difficult to volatilize during subsequent baking.

[0029] Step S20: Take a rigid board and make a hole 2010 to be plugged, forming a plate 200 to be plugged; the hole to be plugged is a copper through hole, which serves to connect the upper and lower layers of circuits, and also provides an ink flow channel for subsequent filling of black resin ink.

[0030] In one embodiment, the size of the plate 200 to be plugged is pre-enlarged on one side, and the pre-enlarged size is greater than or equal to the border width of the frame; that is, the size of the "invalid area" at the edge of the plate 200 to be plugged is enlarged, so that when the black resin ink 100 is screen-printed on the edge of the plate 200 to be plugged, it is not easy to flow to the outer edge of the plate surface of the plate 200 to be plugged, giving enough size for setting the support plate to prevent oil accumulation or uneven plugging.

[0031] Take a screen and make a through-window pattern 3010 corresponding to the hole 2010 to be plugged, forming a blocking point screen 300; the pattern area of ​​the blocking point screen 300 is the area where the black resin ink 100 is leaking by silk screen printing, and this area corresponds to the hole 2010 to be plugged, and the remaining blocking point area is the area where the black resin ink 100 is not leaking. The black resin plugging hole 100 is filled by using the blocking point screen 300 instead of using direct scraping or aluminum sheet, copper sheet tool plugging methods, which has the beneficial effect of effectively avoiding the problems of oil leakage and bulges in the hole 2010 to be plugged. Furthermore, it also provides an easy-to-polish board surface for the subsequent polishing process, avoiding the deformation of the board body caused by multiple polishing due to oil leakage or bulges on the board surface.

[0032] An ink guide plate 400 is manufactured with an ink guide plate hole 4010 to be plugged and an ink guide plate adsorption hole 4020. The ink guide plate adsorption hole 4020 provides a structural basis for the subsequent formation of an adsorption channel. Furthermore, the ink guide plate hole 4010 to be plugged and the hole 2010 to be plugged form a filling channel corresponding to each other, providing a resin flow channel for the subsequent process of using black resin ink 100 for plugging.

[0033] A support plate 500 having the same height as the ink guide plate 400 is manufactured, wherein the support plate 500 is a frame arranged at the edge area of ​​the plate 200 to be plugged with holes; the plate 200 to be plugged with holes is adsorbed onto the support plate 500, so that the support plate 500 forms a supporting function for the thin plate body of the plate 200 to be plugged with holes, plays an auxiliary role in fixing the plate 200 to be plugged with holes, and prevents the plate 200 from slipping and other problems.

[0034] An air guide plate 600 with air guide plate adsorption holes 6020 is manufactured. The air guide plate adsorption holes 6020 correspond to the ink guide plate adsorption holes 4020 to form an adsorption channel, which provides a processing basis for the subsequent process of placing the plugged hole plate 200 in a vacuum machine for vacuuming to adsorb and fix it to the support plate 500.

[0035] The air guide plate 600, the ink guide plate 400, the plate to be plugged 200 and the blocking point screen 300 are stacked in sequence from bottom to top, and the ink guide plate 400 is arranged within the frame of the support plate 500 to form a plugging processing structure 10; it provides a processing basis for the plugging processing in the subsequent process; by setting the structure of the ink guide plate 400 and the support plate 500, rather than just the structure of the ink guide plate 400, on the one hand, the support for the plate to be plugged 200 can be improved, and on the other hand, it is also convenient to assist the fixing, disassembly and other processing of the plate to be plugged 200.

[0036] In the present embodiment, the ink guide plate adsorption holes 4020 and the air guide plate adsorption holes 6020 are both copper-free holes, and the ink guide plate adsorption holes 4020 and the air guide plate adsorption holes 6020 are connected to each other to form an adsorption channel, and the ink guide plate adsorption holes 4020 correspond to the plate body (without hole distribution) in the hole plate 200 to be plugged, forming an adsorption force on the hole plate 200 to be plugged, and in a vacuum environment, the hole plate 200 to be plugged is adsorbed onto the plate surface, which plays the role of leveling the surface of the hole plate 200 to be plugged, and assisting the processing of the hole plate 200 to be plugged, so as to prevent the surface of the hole plate 200 to be plugged from being uneven, resulting in problems such as leaking holes, oil accumulation on the plate surface, and poor plugging.

[0037] In particular, one side of the blocking dot screen 300 is larger than the hole plate 200 to be plugged, so as to avoid problems such as the black resin ink 100 flowing from the edge of the blocking dot screen 300 to the hole plate 200 to be plugged during the screen printing process, causing contamination of the plate surface. The one side of the air guide plate 600 is larger than the ink guide plate 400 to form a stepped shape, which plays a role in enhancing the stability of the plugging processing structure 10 on the vacuum table when the vacuum processing is performed in the vacuum machine.

[0038] Step S30: The plugging structure 10 is used to perform plugging processing on the plugged plate 200 , and then the plugged plate 20 is formed by baking and polishing in sequence.

[0039] In this embodiment, the plugging process is to use the plugging processing structure 10 to perform vacuum plugging on the hole plate 200 to be plugged, that is, to make a vacuum table 700, the vacuum table includes a vacuum groove 7010 and a table exhaust hole 7020, and the support plate 500, the ink guide plate 400, and the air guide plate 600 are fixed to the vacuum table 700 with pins. The area of ​​the vacuum table 700 is larger than the area of ​​the air guide plate 600, and is placed in a stepped manner with the plugging processing structure 10. The black resin ink 100 is filled in a vacuum state, and can be more evenly filled into various parts of the channel to be plugged, which greatly reduces the generation of bubbles and gaps, improves the density of the black resin ink 100 in the hole 2010 to be plugged, and makes the filling accuracy of the hole 2010 to be plugged high after baking and curing in the post-process. Since the carbon black powder added when preparing the black resin ink 100 absorbs heat quickly, the baking is performed in stages, with baking at 120°C for 10 minutes, 130°C for 10 minutes, and 140°C for 30 minutes, to gradually heat up the black resin ink 100 and avoid problems such as oil explosion on the plugging plate 200 caused by a single baking that causes the temperature to be too high all of a sudden.

[0040] In this embodiment, the grinding is a single grinding. On the one hand, due to the high-precision processing of the hole 2010 to be plugged in this embodiment, the protruding black resin ink 100 is less and can be polished flat with a single grinding. On the other hand, due to the thin thickness of the plate, multiple grindings can easily lead to deformation of the plate, excessive grinding, or even tearing.

[0041] See also Figure 3 and Figure 4 , Figure 3 Schematic diagram of optical scanning of a plug hole plate according to an embodiment of the present invention, Figure 4 It is a schematic diagram of the cross-sectional structure of a thin high-precision back-attached circuit board according to an embodiment of the present invention.

[0042] Step S40: A film 800 is manufactured, wherein the light-transmitting area 8010 of the film 800 corresponds to the hole 2010 to be plugged, and the film 800 is attached to the surface of the plugging plate 200 to form a detection plate 30, and optical scanning is used to check the plugging yield rate; and then after post-processing, a thin and high-precision back-attached circuit board 30 is formed, that is, the light-transmitting area 8010 of the film 800 corresponds to the hole 2010 to be plugged, and the light-shielding area 8020 covers the remaining area of ​​the board surface; in this embodiment, optical scanning is used to check the plugging yield rate, which includes the following steps: designing computer graphics data that only includes the hole 2010 to be plugged, using automatic optical detection equipment to scan the detection board 30 to form a detection pattern, comparing the computer graphics data with the detection pattern, and checking the plugging yield rate.

[0043] In addition to the holes for resin plugging, there are other through holes such as plug-in holes on the board surface. Using the 8010 pattern of the film light-transmitting area to compare the plugging holes can form a more uniform and systematic optical color difference effect, prevent interference from other patterns on the board surface, or interference from the uneven board surface, resulting in excessive color difference and misinspection, and can form a more accurate graphic contrast effect, reduce the color error generated 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 during AOI optical scanning, the scanned board surface will present a uniform black color under the best lighting parameters. If the plugged hole is 20 If the plugging of the hole 10 is good, the scanned image will be completely black. If the resin plugging is poor, the hole is missing, or the hole is half-plugged, the scanned image will have light-transmitting spots. The hole to be plugged 2010 corresponding to the light-transmitting spot can be repaired, or the plugging processing structure and plugging processing parameters can be adjusted accordingly according to the type of problem. If the plugging problem is serious, the hole will be scrapped. Because the hole to be plugged 2010 does not need to be light-transmitting, the computer graphic data is completely black graphic data, and the design and application are very simple. AOI is used for scanning and comparison. If there are light leakage or light-transmitting points, it means that the hole to be plugged 2010 has problems such as missing plugging or poor plugging.

[0044] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a thin high-precision back-attached circuit board, characterized in that: The production method comprises the following steps: S10: taking resin ink and mixing it to form black resin ink; S20: Take a rigid plate and make holes to be plugged to form a plate to be plugged; Taking a screen, making a through-window pattern corresponding to the hole to be plugged, and forming a blocking point screen; Manufacturing an ink guide plate having an ink guide plate adsorption hole and an ink guide plate plugging hole, wherein the ink guide plate plugging hole corresponds to the plugging hole; Making a support plate with the same height as the ink guide plate, wherein the support plate is a frame arranged at the edge area of ​​the plate to be plugged; Making 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; The air guide plate, the ink guide plate, the plate to be plugged and the blocking point screen are stacked in sequence from bottom to top, and the ink guide plate is arranged inside the frame to form a plugging processing structure; S30: performing plugging processing on the plate to be plugged using the plugging processing structure, and then baking and polishing in sequence to form a plugged plate; S40: manufacturing a film, wherein the light-transmitting area of ​​the film corresponds to the hole to be plugged, attaching the film to the surface of the plugging plate to form a detection plate, and using optical scanning to check the plugging hole yield; After further post-processing, the thin high-precision back-attached circuit board is formed.

2. A method for manufacturing a thin high-precision back-attached circuit board as claimed in claim 1, characterized in that: The preparation is to take carbon black powder, add it to a solvent, stir it evenly to form a carbon black additive, add the carbon black additive to the resin ink, stir it evenly to form the black resin ink.

3. A method for manufacturing a thin high-precision back-attached circuit board as claimed in claim 2, characterized in that: The solvent is propylene glycol methyl ether, ethylene glycol tert-butyl ether, diethyl carbonate or propylene glycol methyl ether acetate.

4. A method for manufacturing a thin high-precision back-attached circuit board as claimed in claim 2 or 3, characterized in that: 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%.

5. The method for manufacturing a thin high-precision back-attached circuit board according to claim 1, characterized in that: The ink guide plate adsorption holes and the air guide plate adsorption holes are both copper-free holes.

6. A method for manufacturing a thin high-precision back-attached circuit board as claimed in claim 5, characterized in that: The plugging process is to use the plugging process structure to perform vacuum plugging on the plate to be plugged.

7. A method for manufacturing a thin high-precision back-attached circuit board as claimed in claim 1, characterized in that: The size of the plate to be plugged is pre-enlarged on one side, and the pre-enlarged size is greater than or equal to the border width of the frame.

8. The method for manufacturing a thin high-precision back-attached circuit board according to claim 1, characterized in that: The baking is performed in stages, and the baking is performed at 120° C. for 10 minutes, at 130° C. for 10 minutes, and at 140° C. for 30 minutes.

9. A method for manufacturing a thin high-precision back-attached circuit board as claimed in claim 1, characterized in that: The grinding is a single grinding.

10. The method for manufacturing a thin high-precision back-attached circuit board according to claim 1, characterized in that: The method of using optical scanning to check the plug hole yield rate comprises the following steps: The design only includes computer graphics data of the holes to be plugged, and the inspection board is scanned using automatic optical inspection equipment to form an inspection pattern. The computer graphics data is compared with the inspection pattern to check the yield rate of the plugged holes.

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