Circuit board manufacturing method and circuit board

Abstract

The invention relates to the technical field of circuit board manufacturing, in particular to a circuit board manufacturing method and a circuit board. The circuit board manufacturing method at least comprises the following steps that a first blind hole is formed in a substrate, and an orifice of the first blind hole faces a first direction; arranging a conductive layer on the inner wall of the first blind hole; and removing the conductive layer on the hole bottom of the first blind hole, and removing the substrate corresponding to the hole bottom of the first blind hole. The first blind hole is formed in the substrate, and then the conductive layer is arranged on the inner wall of the first blind hole, so that the first blind hole generated by the above steps is the plated-through hole, and the plated-through hole does not penetrate through the substrate; and only the conductive layer on the hole bottom of the first blind hole needs to be removed and the substrate corresponding to the hole bottom of the first blind hole on the substrate needs to be removed subsequently, so that a cutting mechanism can be prevented from being in contact with the conductive layer on the side wall of the first blind hole, and the problems of burr, strain and stripping of the conductive layer on the side wall of the plated-through hole can be prevented.

Description

Technical Field

[0001] The present application relates to the technical field of circuit board manufacturing, and in particular to a circuit board manufacturing method and a circuit board. Background Art

[0002] With the rapid development of the electronics industry, there are more and more specially designed circuit boards, and the structure of circuit boards is becoming more and more complex. In order to reduce the distortion caused by loss during signal transmission, some unnecessary conductive layers and substrates on the circuit boards need to be removed.

[0003] In the related art, the production process of the circuit board is: front process → mechanical drilling → mechanical hole plating (hole metallization) → outer layer circuit → outer layer etching → AOI (Automated Optical Inspection) → solder mask → immersion gold → depth control gong → molding. When there is a metallized hole at the position of the depth control gong, after the depth control gong, the cutting mechanism of the depth control gong will damage the conductive layer on the side wall of the metallized hole, causing the conductive layer on the side wall of the metallized hole to be burred, stretched and peeled off, resulting in electrical abnormality risks such as short circuit and open circuit in the circuit board. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a circuit board manufacturing method and a circuit board, aiming to solve the problem of burring, tearing and peeling of the conductive layer on the side wall of the metallized hole after removing some unnecessary conductive layers on the circuit board and the substrate.

[0005] To achieve the above-mentioned purpose, the technical solution adopted in the first embodiment of the present application is: a circuit board manufacturing method, comprising at least the following steps:

[0006] A first blind hole is formed on the substrate, wherein the opening of the first blind hole faces a first direction;

[0007] Disposing a conductive layer on the inner wall of the first blind hole;

[0008] The conductive layer on the bottom of the first blind hole is removed, and the substrate corresponding to the bottom of the first blind hole is removed.

[0009] The beneficial effect of the circuit board manufacturing method provided by the present application is that: since a first blind hole is first opened on the substrate and then a conductive layer is arranged on the inner wall of the first blind hole, the first blind hole generated by the above steps is a metallized hole, and the metallized hole does not penetrate the substrate, and subsequently only the conductive layer on the bottom of the first blind hole and the substrate corresponding to the bottom of the first blind hole need to be removed, which can avoid the cutting mechanism from contacting the conductive layer on the side wall of the first blind hole, so as to prevent the conductive layer on the side wall of the metallized hole from having problems such as flashing, tearing and peeling.

[0010] In some embodiments, removing the conductive layer on the bottom of the first blind hole and removing the substrate corresponding to the bottom of the first blind hole comprises the following steps:

[0011] A second blind hole is formed on the substrate, the opening of which faces the opposite direction to the first direction, and the orthographic projection of the bottom of the first blind hole is located within the orthographic projection of the bottom of the second blind hole on a projection plane perpendicular to the first direction;

[0012] The conductive layer on the bottom of the first blind hole is removed, and the substrate between the first blind hole and the second blind hole is removed.

[0013] In some embodiments, removing the conductive layer on the bottom of the first blind hole and removing the substrate between the first blind hole and the second blind hole comprises the following steps:

[0014] The conductive layer on the bottom of the first blind hole and the substrate are etched using a laser with a propagation direction opposite to the first direction to form a through hole that penetrates the conductive layer on the bottom of the first blind hole and the substrate between the first blind hole and the second blind hole.

[0015] In some embodiments, the side wall of the through hole has a first end and a second end arranged opposite to each other, the first end is located on the side of the second end facing the first direction, and the distance between the first end and the central axis of the through hole is farther than the distance between the second end and the central axis of the through hole.

[0016] In some embodiments, a difference between a distance between the first end and a central axis of the through hole and a distance between the second end and the central axis of the through hole is 0.04 mm-0.06 mm.

[0017] In some embodiments, the step of etching the conductive layer on the bottom of the first blind hole and the substrate using a laser having a propagation direction opposite to the first direction comprises the following steps:

[0018] The conductive layer on the bottom of the first blind hole and the substrate are etched by laser with a propagation direction opposite to the first direction to form a plurality of sub-holes coaxially connected in sequence in the first direction, and in the first direction, the distances between the hole walls of the plurality of sub-holes and the central axis of the through hole increase sequentially.

[0019] In some embodiments, a minimum distance between the laser and the conductive layer on the sidewall of the first blind hole is a first distance.

[0020] In some embodiments, the first distance is 0.025 mm-0.05 mm.

[0021] In some embodiments, the substrate has a plurality of circuit sub-boards and connecting sub-boards located between adjacent circuit sub-boards. After etching the conductive layer on the bottom of the first blind hole and the substrate using a laser having a propagation direction opposite to the first direction, the circuit board manufacturing method further includes the following steps:

[0022] Part of the connecting sub-boards between adjacent circuit sub-boards is removed.

[0023] In order to achieve the above-mentioned purpose, the technical solution adopted in the second embodiment of the present application is: a circuit board is manufactured by the circuit board manufacturing method of the first embodiment mentioned above.

[0024] The beneficial effect of the circuit board provided by the present application is that the conductive layer on the side wall of the metallized hole on the circuit board will not have the problems of flashing, pulling and peeling. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 is a flow chart of a circuit board manufacturing method in one of the embodiments of the present application;

[0027] Figure 2 is a schematic diagram of a circuit board manufacturing method in one of the embodiments of the present application, wherein (a) is a schematic diagram of the structure of the substrate after a first blind hole is opened, (b) is a schematic diagram of the structure of the substrate after a conductive layer is provided on the inner wall of the first blind hole, and (c) is a schematic diagram of the structure of the substrate after the conductive layer on the bottom of the first blind hole is removed and the substrate corresponding to the bottom of the first blind hole is removed;

[0028] Figure 3 is a schematic diagram of a circuit board manufacturing method in one of the embodiments of the present application, wherein (a) is a schematic diagram of the structure of the substrate after a first blind hole is formed, (b) is a schematic diagram of the structure of the substrate after a conductive layer is provided on the inner wall of the first blind hole, (c) is a schematic diagram of the structure of the substrate after a second blind hole is formed, and (d) is a schematic diagram of the structure of the substrate after the conductive layer on the bottom of the first blind hole and the substrate between the first blind hole and the second blind hole are removed;

[0029] Figure 4 It is a schematic diagram of the structure of a circuit board in one of the embodiments of the present application.

[0030] Reference numerals:

[0031] 1. Substrate; 11. First blind hole; 12. Second blind hole; 13. Through hole; 131. First end; 132. Second end; 14. Circuit sub-board; 15. Connecting sub-board; 2. Conductive layer. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0035] References to "one embodiment", "some embodiments" or "an embodiment" described in the specification of this application mean that a particular feature, structure or characteristic described in conjunction with the embodiment is included in one or more embodiments of the present application. Thus, the phrases "in one embodiment", "in some other embodiments", "in some other embodiments", etc., which appear at different places in this specification, do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. In addition, in one or more embodiments, particular features, structures or characteristics may be combined in any suitable manner.

[0036] With the rapid development of the electronics industry, there are more and more specially designed circuit boards, and the structure of circuit boards is becoming more and more complex. In order to reduce the distortion caused by loss during signal transmission, some unnecessary conductive layers and substrates on the circuit boards need to be removed.

[0037] In the related art, the production process of the circuit board is: front process → mechanical drilling → mechanical hole plating (hole metallization) → outer layer circuit → outer layer etching → AOI (Automated Optical Inspection) → solder mask → immersion gold → depth control gong → molding. When there is a metallized hole at the position of the depth control gong, after the depth control gong, the cutting mechanism of the depth control gong will damage the conductive layer on the side wall of the metallized hole, causing the conductive layer on the side wall of the metallized hole to be burred, stretched and peeled off, resulting in electrical abnormality risks such as short circuit and open circuit in the circuit board.

[0038] In view of the above problems, the present application provides a circuit board manufacturing method and a circuit board, aiming to solve the problem of burring, tearing and peeling of the conductive layer on the side wall of the metallized hole after removing some unnecessary conductive layers on the circuit board and the substrate.

[0039] In order to illustrate the technical solution of the present application, a description is given below in conjunction with specific drawings and embodiments.

[0040] Please refer to Figure 1 and Figure 2 The present invention provides a method for manufacturing a circuit board, which comprises at least the following steps:

[0041] S100: a first blind hole 11 is opened on the substrate 1, with the opening of the first blind hole 11 facing a first direction (the X direction in the figure).

[0042] S200 : disposing a conductive layer 2 on the inner wall of the first blind hole 11 .

[0043] S300 : removing the conductive layer 2 on the bottom of the first blind hole 11 , and removing the substrate 1 corresponding to the bottom of the first blind hole 11 .

[0044] Since the first blind hole 11 is firstly opened on the substrate 1, and then the conductive layer 2 is arranged on the inner wall of the first blind hole 11, the first blind hole 11 generated by the above steps is a metallized hole, and the metallized hole does not penetrate the substrate 1, and subsequently, only the conductive layer 2 on the bottom of the first blind hole 11 and the substrate 1 corresponding to the bottom of the first blind hole 11 need to be removed, which can avoid the cutting mechanism from contacting the conductive layer 2 on the side wall of the first blind hole 11, so as to prevent the conductive layer 2 on the side wall of the metallized hole from being flashed, scratched and peeled off.

[0045] In some embodiments, when the first blind hole 11 is opened on the substrate 1, other types of holes in the board can also be made simultaneously according to production requirements, such as positioning holes, other non-depth-controlled component holes, mounting holes, etc.

[0046] It should be noted that the composition of the removed substrate 1 in “removing the substrate 1 corresponding to the bottom of the first blind hole 11 ” depends on the structure of the substrate 1 and the depth of the first blind hole 11 .

[0047] Taking the substrate 1 as a three-layer board as an example, the substrate 1 includes a first outer layer board, a first dielectric layer, an inner layer board, a second dielectric layer, and a second outer layer board stacked in a first direction, and the first blind hole 11 passes through the second outer layer board, the second dielectric layer and the inner layer board. Then, removing the substrate 1 corresponding to the bottom of the first blind hole 11 refers to removing the first dielectric layer and the first outer layer board corresponding to the bottom of the first blind hole 11.

[0048] Taking the substrate 1 as a four-layer board as an example, the substrate 1 includes a first outer layer board, a first dielectric layer, a first inner layer board, a second dielectric layer, a second inner layer board, a third dielectric layer and a second outer layer board stacked in a first direction; if the first blind hole 11 passes through the second outer layer board, the third dielectric layer and the second inner layer board, then removing the substrate 1 corresponding to the bottom of the first blind hole 11 means removing the second dielectric layer, the first inner layer board, the first dielectric layer and the first outer layer board corresponding to the bottom of the first blind hole 11; if the first blind hole 11 passes through the second outer layer board, the third dielectric layer, the second inner layer board, the second dielectric layer and the first inner layer board, then removing the substrate 1 corresponding to the bottom of the first blind hole 11 means removing the first dielectric layer and the first outer layer board corresponding to the bottom of the first blind hole 11.

[0049] It should be noted that the depth control in the related art means that the automatic machine tool with a program control system can strictly control the processing depth. The depth control gong in this application is a method of removing the substrate 1 of a predetermined depth using the above-mentioned automatic machine tool.

[0050] In the circuit board manufacturing method of the embodiment of the present application, the depth-controlled milling method can be used to remove the conductive layer 2 on the bottom of the first blind hole 11 and remove the substrate 1 corresponding to the bottom of the first blind hole 11. That is, the milling cutter of the automated machine tool cuts the substrate 1 and the conductive layer 2 along the first direction to sequentially remove the substrate 1 corresponding to the bottom of the first blind hole 11 and the conductive layer 2 on the bottom of the first blind hole 11; or, the milling cutter of the automated machine tool cuts the conductive layer 2 and the substrate 1 along the direction opposite to the first direction to sequentially remove the conductive layer 2 on the bottom of the first blind hole 11 and the substrate 1 corresponding to the bottom of the first blind hole 11.

[0051] It should be noted that when the milling cutter of the automated machine tool cuts the conductive layer 2 and the substrate 1 in a direction opposite to the first direction, in order not to damage the conductive layer 2 on the side wall of the first blind hole 11, the position of the milling cutter needs to be strictly controlled to prevent the milling cutter from contacting the conductive layer 2 on the side wall of the first blind hole 11.

[0052] It should be noted that when the milling cutter of the automated machine tool cuts the substrate 1 and the conductive layer 2 along the first direction, in order to prevent the conductive layer 2 on the side wall of the first blind hole 11 from being damaged, the distance of the milling cutter relative to the substrate 1 along the first direction needs to be strictly controlled.

[0053] In view of the above problems, in some embodiments, laser etching with higher processing accuracy can be used to remove the conductive layer 2 on the bottom of the first blind hole 11 and the substrate 1 corresponding to the bottom of the first blind hole 11 to avoid damaging the conductive layer 2 on the side wall of the first blind hole 11.

[0054] However, when the substrate 1 corresponding to the bottom of the first blind hole 11 is thicker, the efficiency of laser etching will be lower.

[0055] In view of the above problems, please refer to Figure 3 In some embodiments, removing the conductive layer 2 on the bottom of the first blind hole 11 and removing the substrate 1 corresponding to the bottom of the first blind hole 11 includes the following steps:

[0056] A second blind hole 12 is opened on the substrate 1 with its opening facing in the opposite direction to the first direction, and on a projection plane perpendicular to the first direction, the orthographic projection of the bottom of the first blind hole 11 is located within the orthographic projection of the bottom of the second blind hole 12 .

[0057] The conductive layer 2 on the bottom of the first blind hole 11 is removed, and the substrate 1 between the first blind hole 11 and the second blind hole 12 is removed.

[0058] In the above method, a milling cutter of an automated machine tool can be used to cut the substrate 1 along a first direction to form a second blind hole 12, and then a laser can be used to etch the substrate 1 to remove the conductive layer 2 on the bottom of the first blind hole 11 and to remove the substrate 1 corresponding to the bottom of the first blind hole 11, thereby improving the processing efficiency of the circuit board.

[0059] Furthermore, in the above embodiment, the milling cutter only cuts the substrate 1, and the conductive layer 2 on the inner wall of the first blind hole 11 does not exist in the area cut by the milling cutter. Therefore, the conductive layer 2 on the inner wall of the first blind hole 11 will not be flaked, scratched or peeled off.

[0060] In some embodiments, after the second blind hole 12 is formed, the thickness of the substrate 1 between the bottom of the first blind hole 11 and the bottom of the second blind hole 12 is 0.035 mm-0.06 mm.

[0061] In some embodiments, removing the conductive layer 2 on the bottom of the first blind hole 11 and removing the substrate 1 between the first blind hole 11 and the second blind hole 12 includes the following steps:

[0062] The conductive layer 2 and the substrate 1 at the bottom of the first blind hole 11 are etched by laser with a propagation direction opposite to the first direction to form a through hole 13 penetrating the conductive layer 2 at the bottom of the first blind hole 11 and the substrate 1 between the first blind hole 11 and the second blind hole 12.

[0063] The basic principle of laser etching is to focus a low-power laser with high beam quality on a very small light spot, form a high power density at the focus, and evaporate the material instantly. In the above embodiment, since the propagation direction of the laser is opposite to the first direction, during etching, the focus will first contact the surface of the conductive layer 2 on the bottom of the first blind hole 11 facing the first direction, which can more intuitively determine the relative position between the laser and the conductive layer 2 on the side wall of the first blind hole 11, which is helpful for laser positioning and can avoid laser etching of the conductive layer 2 on the side wall of the first blind hole 11 due to inaccurate positioning.

[0064] Please refer to Figure 3 In some embodiments, the side wall of the through hole 13 has a first end 131 and a second end 132 that are oppositely arranged, the first end 131 is located on the side of the second end 132 facing the first direction, and the distance between the first end 131 and the central axis of the through hole 13 is farther than the distance between the second end 132 and the central axis of the through hole 13.

[0065] In the above embodiment, the first end 131 encloses one of the openings of the through hole 13, and the second end 132 encloses the other opening of the through hole 13. The opening enclosed by the first end 131 is wider than the opening enclosed by the second end 132. When plugging in a plug-in, it helps the pin of the plug-in to enter the through hole 13 through the opening enclosed by the first end 131.

[0066] In some embodiments, the difference between the distance between the first end 131 and the central axis of the through hole 13 and the distance between the second end 132 and the central axis of the through hole 13 is 0.04 mm-0.06 mm.

[0067] It should be noted that, when the aperture of the first blind hole 11 is determined, the distance between the first end 131 and the central axis of the through hole 13 is determined, and the greater the difference between the distance between the first end 131 and the central axis of the through hole 13 and the distance between the second end 132 and the central axis of the through hole 13, the narrower the orifice formed by the second end 132 will be; the smaller the difference between the distance between the first end 131 and the central axis of the through hole 13 and the distance between the second end 132 and the central axis of the through hole 13, the wider the orifice formed by the second end 132 will be; if the orifice formed by the second end 132 is too narrow, it is not conducive for the pin of the plug-in to pass through the orifice formed by the second end 132; if the orifice formed by the second end 132 is too wide, it is not conducive to limiting the position of the pin of the plug-in, making the plug-in easy to loosen. Therefore, in the embodiment of the present application, the difference between the distance between the first end 131 and the central axis of the through hole 13 and the distance between the second end 132 and the central axis of the through hole 13 is controlled to be between 0.04 mm and 0.06 mm, so that the hole formed by the second end 132 can allow the pin of the plug-in to pass through, and the hole formed by the second end 132 can also limit the position of the pin of the plug-in to help fix the plug-in.

[0068] Optionally, the difference between the distance between the first end 131 and the central axis of the through hole 13 and the distance between the second end 132 and the central axis of the through hole 13 is 0.05 mm.

[0069] It should be noted that, in order to avoid the laser contacting the conductive layer 2 on the side wall of the first blind hole 11, the present application adopts a laser parallel to the first direction, and the side wall of the through hole 13 etched by the laser is a plane parallel to the first direction. Therefore, in order to achieve the effect that the distance between the first end 131 on the side wall of the through hole 13 and the central axis of the through hole 13 is farther than the distance between the second end 132 and the central axis of the through hole 13, laser etching of the substrate 1 can be used to form a plurality of sub-holes that are coaxially connected in sequence in the first direction, and in the first direction, the distances between the hole walls of the plurality of sub-holes and the central axis of the through hole 13 increase in sequence.

[0070] In one embodiment, the through hole 13 includes four sub-holes. In the first direction, the four sub-holes are the first sub-hole, the second sub-hole, the third sub-hole and the fourth sub-hole in sequence. The distance between the hole wall of the fourth sub-hole and the central axis of the through hole 13 is greater than the distance between the hole wall of the third sub-hole and the central axis of the through hole 13 by D1. The distance between the hole wall of the third sub-hole and the central axis of the through hole 13 is greater than the distance between the hole wall of the second sub-hole and the central axis of the through hole 13 by D2. The distance between the hole wall of the second sub-hole and the central axis of the through hole 13 is greater than the distance between the hole wall of the first sub-hole and the central axis of the through hole 13 by D3, wherein D2=D1*(0.6-0.8), for example, D2=D1*0.75; D3=D1*(0.4-0.6), for example, D3=D1*0.5.

[0071] Optionally, the effective spot diameter of the laser is 16um-23um, for example, the effective spot diameter of the laser is 20um.

[0072] Optionally, the cutting speed of the laser is 400 mm / S-600 mm / S, for example, the cutting speed of the laser is 500 mm / S.

[0073] In some embodiments, to avoid laser etching of the conductive layer 2 on the sidewall of the first blind hole 11 due to laser deviation, the minimum distance between the laser and the conductive layer 2 on the sidewall of the first blind hole 11 is a first distance.

[0074] In some embodiments, the first distance is 0.025 mm-0.05 mm.

[0075] Optionally, the first distance is 0.03 mm, 0.04 mm or 0.045 mm.

[0076] It should be noted that, in order to improve the production efficiency of the circuit board, multiple independent circuit sub-boards 14 will be produced on the entire substrate 1. After the production is completed, the substrate 1 can be split into independent circuit sub-boards 14. Please refer to Figure 4 During production, in order to facilitate subsequent splitting, some connecting sub-boards 15 between the circuit sub-boards 14 will be removed in advance, leaving only a small portion of the connecting sub-boards 15 connecting adjacent circuit sub-boards 14.

[0077] In the circuit board manufacturing method of the embodiment of the present application, before using a laser to remove the conductive layer 2 on the bottom of the first blind hole 11 and removing the substrate 1 between the first blind hole 11 and the second blind hole 12, it is necessary to vacuum absorb the substrate 1 and transfer the substrate 1 to the laser etching station. In order to avoid damage to the circuit sub-board 14, a suction cup is required to absorb the position of the connecting sub-board 15 on the substrate 1. Therefore, before the laser removes the conductive layer 2 on the bottom of the first blind hole 11 and removes the substrate 1 between the first blind hole 11 and the second blind hole 12, it is necessary to retain the connecting sub-board 15, and retaining the connecting sub-board 15 can also avoid the problem of board surface warping caused by the asymmetric structure of the substrate 1.

[0078] In view of the above situation, in some embodiments, after the substrate 1 is etched with a laser having a propagation direction opposite to the first direction, a portion of the connecting sub-boards 15 between adjacent circuit sub-boards 14 is removed.

[0079] In one embodiment, after using a laser with a propagation direction opposite to the first direction to etch the substrate 1 and remove the conductive layer 2 on the bottom of the first blind hole 11, and remove the substrate 1 between the first blind hole 11 and the second blind hole 12, the suction cup sucks the position of the connecting sub-board 15 on the substrate 1, transfers the substrate 1 to an automated machine tool, and uses a milling cutter to cut part of the connecting sub-board 15 between the circuit sub-boards 14.

[0080] In some embodiments, the conductive layer 2 is disposed on the inner wall of the first blind hole 11, comprising the following steps:

[0081] A plating seed layer is deposited on the inner wall of the first blind hole 11 by chemical copper plating, vacuum sputtering or vapor deposition.

[0082] A copper layer is superimposed on the electroplating seed layer through an electrochemical reaction.

[0083] In some embodiments, the following steps are further included between step S200: providing a conductive layer 2 on the inner wall of the first blind hole 11 and step S300: removing the conductive layer 2 on the bottom of the first blind hole 11 and removing the corresponding substrate 1 at the bottom of the first blind hole 11:

[0084] Outer layer pattern transfer: The outer layer pattern transfer is completed after the substrate 1 undergoes the outer layer pre-treatment → film lamination → exposure → development process, that is, the required circuit is retained by exposure, and the area to be etched is not exposed and developed.

[0085] Outer layer etching: Use acid etching solution to remove the undeveloped dry film on the circuit to obtain the outer layer circuit.

[0086] AOI: Optically inspect the substrate 1 after the outer layer circuit etching is completed.

[0087] Solder mask: Substrate 1 undergoes solder mask pre-treatment → solder mask printing → pre-baking → exposure → development, and a window is opened in the required pad area, and the remaining positions are protected with solder mask.

[0088] In some embodiments, the step of removing the conductive layer 2 on the bottom of the first blind hole 11 and removing the substrate 1 corresponding to the bottom of the first blind hole 11 further includes the following steps:

[0089] Chemical cleaning: Remove the residual carbide on the substrate 1 through a chemical degumming tank at a speed of 2m / min.

[0090] Immersion Gold: Immersion gold is applied to the solder mask window pad and the hole wall of the metallized hole after the window is opened, which plays a protective role and is beneficial to the welding of the pad.

[0091] Molding: The substrate 1 is cut into a specified size. During molding, only a portion of the connecting sub-boards 15 for connecting the circuit sub-boards 14 is left, and the remaining connecting sub-boards 15 are removed. Therefore, the obtained circuit sub-boards 14 are easy to separate.

[0092] After molding, the post-process (testing, FQC, FQA, packaging) is completed normally.

[0093] In order to achieve the above-mentioned purpose, the technical solution adopted in the second embodiment of the present application is: a circuit board is manufactured by the circuit board manufacturing method of the first embodiment mentioned above.

[0094] The conductive layer 2 on the side wall of the metallized hole on the circuit board will not have the problem of flashing, tearing and peeling.

[0095] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for manufacturing a circuit board, characterized in that: At least the following steps are included: A first blind hole is formed on the substrate, wherein the opening of the first blind hole faces a first direction; Disposing a conductive layer on the inner wall of the first blind hole; The conductive layer on the bottom of the first blind hole is removed, and the substrate corresponding to the bottom of the first blind hole is removed.

2. The method for manufacturing a circuit board according to claim 1, characterized in that: The removing of the conductive layer on the bottom of the first blind hole and the removing of the substrate corresponding to the bottom of the first blind hole comprises the following steps: A second blind hole is formed on the substrate, the opening of which faces the opposite direction to the first direction, and the orthographic projection of the bottom of the first blind hole is located within the orthographic projection of the bottom of the second blind hole on a projection plane perpendicular to the first direction; The conductive layer on the bottom of the first blind hole is removed, and the substrate between the first blind hole and the second blind hole is removed.

3. The method for manufacturing a circuit board according to claim 2, characterized in that: The removing of the conductive layer on the bottom of the first blind hole and the removing of the substrate between the first blind hole and the second blind hole comprises the following steps: The conductive layer on the bottom of the first blind hole and the substrate are etched using a laser with a propagation direction opposite to the first direction to form a through hole that penetrates the conductive layer on the bottom of the first blind hole and the substrate between the first blind hole and the second blind hole.

4. The method for manufacturing a circuit board according to claim 3, characterized in that: The side wall of the through hole has a first end and a second end arranged opposite to each other, the first end is located on the side of the second end facing the first direction, and the distance between the first end and the central axis of the through hole is farther than the distance between the second end and the central axis of the through hole.

5. The method for manufacturing a circuit board according to claim 4, characterized in that: A difference between a distance between the first end and a central axis of the through hole and a distance between the second end and the central axis of the through hole is 0.04 mm to 0.06 mm.

6. The method for manufacturing a circuit board according to claim 3, characterized in that: The method of etching the conductive layer on the bottom of the first blind hole and the substrate using a laser having a propagation direction opposite to the first direction comprises the following steps: The conductive layer on the bottom of the first blind hole and the substrate are etched by laser with a propagation direction opposite to the first direction to form a plurality of sub-holes coaxially connected in sequence in the first direction, and in the first direction, the distances between the hole walls of the plurality of sub-holes and the central axis of the through hole increase sequentially.

7. The method for manufacturing a circuit board according to claim 3, characterized in that: The minimum distance between the laser and the conductive layer on the side wall of the first blind hole is a first distance.

8. The method for manufacturing a circuit board according to claim 7, characterized in that: The first distance is 0.025 mm-0.05 mm.

9. The method for manufacturing a circuit board according to any one of claims 3 to 7, characterized in that: The substrate has a plurality of circuit sub-boards and connecting sub-boards located between adjacent circuit sub-boards. After the conductive layer on the bottom of the first blind hole and the substrate are etched using a laser having a propagation direction opposite to the first direction, the circuit board manufacturing method further includes the following steps: Part of the connecting sub-boards between adjacent circuit sub-boards is removed.

10. A circuit board, characterized in that: The circuit board is manufactured by the circuit board manufacturing method described in any one of claims 1 to 9.

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