CN114222434A - Manufacturing method of step circuit and circuit board - Google Patents
Manufacturing method of step circuit and circuit board Download PDFInfo
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- CN114222434A CN114222434A CN202111318312.3A CN202111318312A CN114222434A CN 114222434 A CN114222434 A CN 114222434A CN 202111318312 A CN202111318312 A CN 202111318312A CN 114222434 A CN114222434 A CN 114222434A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
- H05K3/022—Processes for manufacturing precursors of printed circuits, i.e. copper-clad substrates
- H05K3/025—Processes for manufacturing precursors of printed circuits, i.e. copper-clad substrates by transfer of thin metal foil formed on a temporary carrier, e.g. peel-apart copper
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/11—Printed elements for providing electric connections to or between printed circuits
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
- H05K3/42—Plated through-holes or plated via connections
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- Microelectronics & Electronic Packaging (AREA)
- Manufacturing & Machinery (AREA)
- Printing Elements For Providing Electric Connections Between Printed Circuits (AREA)
- Manufacturing Of Printed Circuit Boards (AREA)
Abstract
The application relates to the technical field of circuit boards, and provides a manufacturing method of a step circuit and a circuit board, wherein the manufacturing method comprises the following steps: manufacturing a substrate; drilling a blind hole on the copper foil layer on one side, wherein the blind hole penetrates through the copper foil layer on one side and the base material and is communicated with the copper foil layer on the other side; performing pattern transfer once, namely performing pattern transfer once on the surfaces of the copper foil layers on the two sides, and performing copper plating operation once to form a thin copper circuit and a thick copper circuit with first preset thicknesses at the preset thin copper circuit and the preset thick copper circuit; conducting treatment of the blind hole; secondary pattern transfer, namely performing secondary pattern transfer on the thick copper circuit with the first preset thickness, and performing secondary copper plating operation to form a thick copper circuit with a second preset thickness at the position of the preset thick copper circuit; the copper foil layer is etched to obtain a step circuit. This application can carry out quick etching, the emergence of control side etching phenomenon to obtain the ladder circuit that circuit rectangle structure is good, precision is high.
Description
Technical Field
The application relates to the technical field of circuit boards, and particularly provides a manufacturing method of a step circuit and a circuit board.
Background
The miniaturization and intelligent development of electronic products promote the basic element of the electronic products, namely Printed Circuit Boards (PCBs), to also tend to develop in the direction of precision and diversification. In recent years, an arbitrary layer interconnection technology has been developed on the basis of a high density interconnection board (HDI board). The interconnection of any layer is realized by all laser micropores between each layer of the fingerprint circuit board, mechanical through holes are not used, each inch space can be fully utilized by adopting the design of any layer, the wiring density is greatly improved, and the product design is more precise and flexible.
The step line means that there are two kinds of lines having different thicknesses in the same line layer of the circuit board. In a conventional PCB product, two methods for manufacturing a step circuit board are provided, as follows:
1. copper is plated on the whole board until the thickness of copper needed by the thin copper circuit is thick, the thin copper circuit area is protected by a dry film, copper is plated on the thick copper circuit area, the dry film is removed, the whole board is coated with a wet film, and after exposure and development, the circuits of the thick copper area and the thin copper area are etched together to form a step circuit;
2. and directly using a plate with the copper thickness required by the thick copper circuit, reducing copper in the area to be manufactured with the thin copper circuit until the copper thickness required by the thin copper circuit is obtained, and carrying out exposure, development and etching after pressing a dry film on the plate surface to form the step circuit.
The above scheme has drawbacks for the step line fabrication of any layer of interconnection plates. In both the scheme 1 and the scheme 2, the preset copper thickness of the corresponding circuit area is obtained, and then the circuit is etched together to form the circuit, but due to the difference of the copper thickness, the thinner circuit is etched earlier, and the thicker circuit is still etched, so that the thin copper circuit etched earlier can continue to carry out lateral etching on the copper on the side, and the circuit has serious lateral etching, a circuit rectangular structure is poor, and the precision is not high. In addition, the thick copper area is difficult to design a fine circuit, which affects the circuit precision. Simultaneously, scheme 2 directly uses thick copper plate to process, has violated the original purpose that arbitrary layer interconnection board chooseed the accurate thin circuit of thin copper preparation.
Disclosure of Invention
An object of the embodiments of the present application is to provide a method for manufacturing a ladder circuit and a circuit board, which aim to solve the problem that the conventional method for manufacturing a ladder circuit board may cause a severe lateral etching phenomenon.
In order to achieve the above purpose, the embodiment of the present application adopts the following technical solutions:
in a first aspect, an embodiment of the present application provides a method for manufacturing a ladder line, including: manufacturing a substrate, wherein the substrate comprises a base material and copper foil layers arranged on two opposite sides of the base material; drilling a blind hole on the copper foil layer on one side, wherein the blind hole penetrates through the copper foil layer on one side and the base material and is communicated with the copper foil layer on the other side; performing pattern transfer once, namely performing pattern transfer once on the surfaces of the copper foil layers on the two sides, and performing copper plating operation once to form a thin copper circuit and a thick copper circuit with first preset thicknesses at the preset thin copper circuit and the preset thick copper circuit; conducting treatment of the blind hole; secondary pattern transfer, namely performing secondary pattern transfer on the thick copper circuit with the first preset thickness, and performing secondary copper plating operation to form a thick copper circuit with a second preset thickness at the position of the preset thick copper circuit; and etching the copper foil layer, and quickly etching the copper foil layer to obtain the step circuit.
The beneficial effects of the embodiment of the application are as follows: according to the manufacturing method of the step circuit, the two times of pattern transfer and the two times of copper plating operation are respectively carried out on the copper foil layer on the surface of the substrate, and the copper thickness required by the thin copper circuit and the copper thickness required by the thick copper circuit are respectively obtained; the copper plating is carried out twice in the process of pattern transfer twice, so that the part of the circuit to be manufactured is plated with copper, the thickness of the copper foil layer of the circuit to be manufactured is not required to be constant, the copper foil layer is etched only when etching is carried out, and the thickness of the copper foil layer is constant and the same, thereby effectively avoiding the problem of serious side etching caused by etching of base copper with different thicknesses when the conventional subtractive method is used for manufacturing; the step circuit obtained by the manufacturing method of the embodiment of the application has high precision and a better rectangular structure.
In one embodiment, the copper foil layer has a thickness of less than 12 μm.
By adopting the technical scheme, the copper foil layer with the thickness of less than 12 mu m is selected, namely the ultra-thin copper foil is selected, so that the etching time is controlled during etching, and the influence of side etching is reduced.
In one embodiment, the copper foil layer has a thickness of 3 μm to 9 μm.
By adopting the technical scheme, the copper foil layer with the thickness of 3-9 microns is selected, so that rapid etching can be realized, the base copper can be etched and removed in a short time by controlling the etching time, and the circuit structure on the board surface is protected from being damaged to the maximum extent.
In one embodiment, the specific steps of one pattern transfer are as follows: the surfaces of the copper foil layers on the two sides are respectively pasted with a first dry film, and the first dry film covers the hole opening of the blind hole; carrying out exposure and development operation for the first time to remove the first dry film at the preset thin copper circuit and the preset thick copper circuit; then, carrying out copper plating operation once to form a thin copper circuit and a thick copper circuit with first preset thicknesses at the preset thin copper circuit and the preset thick copper circuit; and then removing the first dry film.
By adopting the technical scheme, once pattern transfer is carried out by pasting the first dry film, so that pattern transfer and thickening are carried out at the preset thin copper circuit position and the preset thick copper circuit position, and the thickness of the copper foil layer at other positions is constant.
In one embodiment, the secondary pattern transfer comprises the following specific steps: adhering second dry films to the surfaces of the copper foil layers on the two sides, wherein the second dry films cover the hole opening of the blind hole, the position of the preset thin copper circuit and the position of the preset thick copper circuit; carrying out secondary exposure and development operation to remove the second dry film at the position of the preset thick copper circuit and the hole of the blind hole; then carrying out secondary copper plating operation to form a thick copper circuit with a second preset thickness at the position of the preset thick copper circuit, wherein the blind hole is filled with the copper layer; and then removing the second dry film.
By adopting the technical scheme, secondary pattern transfer is carried out by pasting the second dry film, so that the pattern transfer is carried out at the position of the preset thick copper circuit and the thickness is increased to the second preset thickness, and meanwhile, the blind hole is also filled by the copper layer, so that the process flow is saved, and the production efficiency is improved.
In one embodiment, the thickness of the first dry film is less than the thickness of the second dry film.
By adopting the technical scheme, the first dry film adopts the dry film with thinner thickness, so that the resolution is better, and the manufacturing of a fine circuit is facilitated; the second dry film adopts the thicker dry film to avoid the problem that the etching quality is influenced by film clamping when a thick copper circuit is formed by electroplating.
In one embodiment, the specific method for attaching the second dry film to the predetermined thin copper lines and the surfaces of the two copper foil layers includes: and pasting the second dry film by using a vacuum film pressing machine.
Through adopting foretell technical scheme, because the surface of copper foil layer has formed the circuit when the second dry film is established in the subsides, can form the step between the basic copper that circuit and copper foil layer formed, in order to make the better laminating in surface of second dry film and copper foil layer and circuit, use the vacuum film pressing machine to paste and establish the second dry film.
In one embodiment, the specific method of the blind hole conductive treatment is as follows: and conducting treatment is carried out on the blind hole by using a chemical copper deposition method, a black hole process or a graphene process.
By adopting the technical scheme, the blind holes are subjected to conductive treatment by using a chemical copper deposition method, a black hole process or a graphene process, and the influence on the copper thickness of the surface of the substrate is small.
In one embodiment, in the step of drilling blind holes in one side of the copper foil layer: and drilling blind holes by a machining method of laser ablation. By adopting the technical scheme, the blind hole obtained by the laser ablation processing method has higher accuracy.
In a second aspect, an embodiment of the present application further provides a circuit board, where a step circuit is formed on the circuit board, and the step circuit is manufactured by the above step circuit manufacturing method.
The beneficial effects of the embodiment of the application are as follows: according to the circuit board provided by the embodiment of the application, due to the adoption of the manufacturing method of the step circuit, the circuit rectangular structure of the circuit board is better, and the phenomenon of serious lateral erosion is effectively avoided.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a method for manufacturing a ladder circuit according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of a step circuit manufacturing method according to an embodiment of the present disclosure when a first dry film is attached;
fig. 3 is a schematic structural diagram of a step circuit after first copper plating in the method for manufacturing a step circuit according to the embodiment of the present application;
fig. 4 is a schematic structural diagram of a step circuit provided in the present application after a blind via 13 is subjected to a conductive treatment in a manufacturing method of the step circuit;
fig. 5 is a schematic structural diagram illustrating a second dry film attached to the step circuit manufacturing method according to an embodiment of the present disclosure;
fig. 6 is a schematic structural diagram of the step circuit after the second copper plating in the method for manufacturing the step circuit according to the embodiment of the present application;
fig. 7 is a schematic structural diagram of the step circuit manufacturing method according to the embodiment of the present application after the second dry film is removed;
fig. 8 is a schematic structural diagram of a step line after etching is completed in the method for manufacturing a step line according to the embodiment of the present application.
Wherein, in the figures, the respective reference numerals:
10. a substrate; 11. a substrate; 12. a copper foil layer; 13. blind holes; 14. a thin copper line; 15. a thick copper line; 20. a first dry film; 30. and a second dry film.
Detailed Description
Reference will now be made in detail to the embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application and should not be construed as limiting the present application.
In the description of the present application, it is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, as used herein, refer to an orientation or positional relationship indicated in the drawings, which is for convenience and simplicity of description, and does not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, is not to be considered as limiting.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.
In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
The step line means that there are two kinds of lines having different thicknesses in the same line layer of the circuit board. In a conventional PCB product, a manufacturing method of a step circuit board generally adopts a subtractive method, namely, a whole board is plated with copper to the thickness of copper required by a thin copper circuit, and then a thick copper circuit area is plated with copper to be thickened, so that base copper has two thicknesses of thin copper and thick copper, and after pattern transfer, the base copper with the two thicknesses is etched to obtain the thin copper circuit and the thick copper circuit; or directly copper-plating the whole board to the thickness of copper required by the thick copper circuit, and then reducing the thickness of copper in the thin copper circuit area, wherein the base copper also has two thicknesses of thin copper and thick copper. During the etching process, the base copper at the thinner part is etched firstly, and the base copper at the thicker part is still etched; in the process of waiting for the base copper at the thicker part to be continuously etched, the base copper at the thinner part is etched, and the chemical liquid for etching is continuously etched towards the copper at the two sides, so that the side etching of the circuit at the thin copper area is serious, the circuit can be directly etched and disconnected to form an open circuit more seriously, and the product is scrapped.
Therefore, the method for manufacturing the step circuit and the circuit board are provided, the ultrathin copper foil is used as the base copper, the preset copper thickness of the thin copper circuit area and the preset copper thickness of the thick copper circuit area are respectively obtained through two times of pattern transfer on the ultrathin base copper, the base copper at the moment is the ultrathin copper foil which is not thickened, the thickness of the base copper is kept consistent, the thickness is small, etching time control during fast etching is facilitated, the influence of side etching is effectively reduced, the side etching amount of the circuit is accurately controlled, and the precision is higher.
Referring to fig. 1 to 8, in a first aspect, an embodiment of the present application provides a method for manufacturing a ladder circuit, including: manufacturing a substrate 10, wherein the substrate 10 comprises a base material 11 and copper foil layers 12 arranged on two opposite sides of the base material 11; drilling a blind hole, namely drilling a blind hole 13 on the copper foil layer 12 on one side, wherein the blind hole 13 penetrates through the copper foil layer 12 on one side and the base material 11 and is communicated with the copper foil layer 12 on the other side; performing pattern transfer once on the surfaces of the copper foil layers 12 on the two sides, and performing copper plating operation once to form a thin copper line 14 and a thick copper line 15 with first preset thicknesses at the preset thin copper line and the preset thick copper line; conducting treatment of the blind holes 13; secondary pattern transfer, performing secondary pattern transfer on the thick copper circuit 15 with the first preset thickness, and performing secondary copper plating operation to form a thick copper circuit 15 with a second preset thickness at the position of the preset thick copper circuit; the copper foil layer 12 is etched, and the copper foil layer 12 is rapidly etched to obtain a step circuit.
The first predetermined thickness refers to the thickness of copper required for the thin copper lines 14; and carrying out pattern transfer once on the preset thin copper circuit, and then carrying out copper plating operation once on the preset thin copper circuit and the preset thick copper circuit, so that the thickness required by the thin copper circuit 14 is directly formed at the preset thin copper circuit, and a certain thickness is firstly formed at the preset thick copper circuit for subsequent thickening. The second predetermined thickness refers to a thickness of copper required by the thick copper circuit 15, and the second pattern transfer is performed on the copper layer at the predetermined thick copper circuit, and then the second copper plating operation is performed to form the thickness required by the thick copper circuit 15 at the predetermined thick copper circuit. It can be understood that, through two pattern transfer operations, copper thicknesses with corresponding thicknesses are respectively and correspondingly formed at the position of the preset thin copper circuit and the position of the preset thick copper circuit, the thickness of the copper foil layer 12 without manufacturing the circuits is not changed, and in the subsequent etching process, the thicknesses of the copper foil layers 12 needing to be etched are consistent, which is beneficial to controlling the etching degree.
In the method for manufacturing the step circuit provided by the embodiment of the application, two pattern transfers and two copper plating operations are respectively performed on the copper foil layer 12 on the surface of the substrate 10 to respectively obtain the copper thickness required by the thin copper circuit 14 and the copper thickness required by the thick copper circuit 15; the copper plating is carried out twice in the process of pattern transfer twice, so that the part of the circuit to be manufactured is plated with copper, the thickness of the copper foil layer 12 of the circuit is not required to be manufactured to be constant, and the copper foil layer is etched only when being etched, and the thickness of the copper foil layer is constant and the same, thereby effectively avoiding the problem of serious side etching caused by etching of base copper with different thicknesses when being manufactured by a conventional subtractive method; the step circuit obtained by the manufacturing method of the embodiment of the application has high precision and a better rectangular structure.
In one embodiment, the copper foil layer has a thickness of less than 12 μm. The copper foil can be divided into a plurality of types according to the thickness, wherein the copper foil with the thickness more than 70 mu m is a thick copper foil, the copper foil with the thickness more than 18 mu m and less than 70 mu m is a conventional thick copper foil, the copper foil with the thickness more than 12 mu m and less than 18 mu m is a thin copper foil, and the copper foil with the thickness less than 12 mu m is an ultrathin copper foil; the thickness of the copper foil layer 12 in this embodiment is selected to be smaller than 12 μm, that is, the copper foil layer 12 is an ultra-thin copper foil, so as to control the etching time during etching and reduce the influence of side etching.
In one embodiment, copper foil layer 12 has a thickness of 3 μm to 9 μm. The copper foil layer 12 with the thickness of 3-9 microns is selected, rapid etching can be achieved, the copper foil layer 12 can be etched and removed in a short time by controlling the etching time, and the circuit structure on the board surface is protected from being damaged to the maximum extent. It is understood that if the copper foil layer 12 is a conventional thick copper foil, the copper reduction is required to obtain a copper foil with a predetermined thickness, but the amount of copper reduction and uniformity of copper thickness should be strictly controlled, otherwise the etching of fine lines at a later stage is not facilitated. The copper foil layer 12 is preferably a low-profile copper foil or an ultra-low profile copper foil, which is not conducive to rapid etching in subsequent processes due to the high roughness of standard copper foils.
In one embodiment, the specific steps of one pattern transfer are as follows: the surfaces of the copper foil layers 12 on the two sides are respectively pasted with a first dry film 20, and the first dry film 20 covers the hole opening of the blind hole 13; carrying out exposure and development operation for one time, carrying out photocuring on the first dry film 20 at the position where copper plating is not needed to be carried out, and removing the first dry film 20 which is not photocured through development so as to remove the first dry film 20 at the position of a preset thin copper circuit and the position of a preset thick copper circuit; then, carrying out copper plating operation once to form a thin copper line 14 and a thick copper line 15 with first preset thicknesses at the preset thin copper line and the preset thick copper line; the first dry film 20 is then removed. The pattern transfer is performed once by attaching the first dry film 20, so that the pattern transfer and thickening are performed at the preset thin copper line and the preset thick copper line, and the thickness of the copper foil layer 12 at other places is constant, so that the subsequent rapid etching is performed.
In one embodiment, the secondary pattern transfer comprises the following specific steps: the surfaces of the copper foil layers 12 on the two sides are respectively pasted with a second dry film 30, and the second dry films 30 cover the hole opening of the blind hole 13, the position of a preset thin copper circuit and the position of a preset thick copper circuit; carrying out secondary exposure and development operation, carrying out photocuring on the second dry film 30 at the position where copper plating thickening is not needed, and removing the second dry film 30 which is not photocured through development so as to remove the second dry film 30 at the position of a preset thick copper circuit and the hole of the blind hole 13; then, carrying out secondary copper plating operation to form a thick copper circuit 15 with a second preset thickness at the position of the preset thick copper circuit, wherein the blind hole 13 is filled with a copper layer; the second dry film 30 is removed. The second dry film 30 is attached to perform secondary pattern transfer, so that the pattern transfer is performed at the position of the preset thick copper circuit and the thickness of the preset thick copper circuit is increased to the second preset thickness, and meanwhile, the blind hole 13 is also filled with the copper layer, so that the process flow is saved, and the production efficiency is improved.
In one embodiment, the thickness of the first dry film 20 is less than the thickness of the second dry film 30. The first dry film 20 is a dry film with a thinner thickness, so that the resolution is better, and the manufacturing of a fine circuit is facilitated; the second dry film 30 uses a thicker dry film to avoid the problem of etching quality being affected by film clamping during the formation of the thick copper circuit 15 by electroplating.
In one embodiment, the specific method for performing secondary copper plating is as follows: copper plating was performed using a vertical continuous copper electroplating apparatus. During secondary copper plating, copper filling of the blind holes 13 and copper thickness thickening operation of the preset thick copper circuit are completed together, and compared with a conventional mode of firstly filling holes in a whole board and then manufacturing the circuit, the process flow is saved. Wherein, carrying out secondary copper plating to blind hole 13 uses perpendicular continuous type electro-coppering equipment to carry out, utilizes perpendicular continuous type electro-coppering equipment can carry out copper plating to blind hole 13 hole filling operation more effectively.
In one embodiment, blind holes 13 are formed by a machining method of laser ablation. The blind hole 13 obtained by the laser ablation processing method has higher accuracy.
In one embodiment, the specific method for attaching the second dry film 30 at the predetermined thin copper lines and on the surfaces of the two copper foil layers 12 is as follows: the second dry film 30 is applied using a vacuum laminator. Since the surface of the copper foil layer 12 has formed a circuit when the second dry film 30 is attached, a step may be formed between the circuit and the copper foil layer 12, and the second dry film 30 is attached using a vacuum laminator in order to make the second dry film 30 better attached to the surfaces of the copper foil layer 12 and the circuit.
In one embodiment, the blind via conductive treatment may be performed by using any one of a electroless copper plating method, a black via process, or a graphene process. In this embodiment, a chemical copper deposition method is used to specifically describe, a compact thin copper layer is formed on the wall of the blind hole 13 by using a chemical copper deposition method on the whole substrate 10, so that an electrical connection is formed between the blind hole and the copper layer on the surface of the board, thereby facilitating the subsequent copper plating operation. Since electroless copper plating is performed on the entire substrate, thin copper is deposited on the surface of the substrate 10, but the copper layer thickness caused by electroless copper plating is thin, and the shape of the circuit and subsequent rapid etching are hardly affected.
In one embodiment, in the step of drilling blind holes in one side of the copper foil layer: and drilling blind holes by a machining method of laser ablation. The blind hole obtained by the laser ablation processing method has higher accuracy.
Referring to fig. 1 to 8, in a second aspect, an embodiment of the present application further provides a circuit board, where a step circuit is formed on the circuit board, and the step circuit is manufactured by the above-mentioned step circuit manufacturing method. According to the circuit board provided by the embodiment of the application, due to the adoption of the manufacturing method of the step circuit, the circuit rectangular structure of the circuit board is better, and the phenomenon of serious lateral erosion is effectively avoided.
The method for manufacturing the step circuit can be applied to a common multilayer substrate and any multilayer interconnection substrate besides the double-sided copper-clad substrate in the embodiment.
Taking six layers of interconnection plates with ladder circuits designed on the outermost layer and any layer as an example, the ladder circuits are only designed on the first layer and the sixth layer, wherein the second layer to the fifth layer are processed according to the conventional manufacturing process of interconnection plates with any layer, and the complete production process of the circuit board is illustrated. Firstly, cutting a copper-clad plate large material into a work class with a specified size according to the size requirement of production makeup, treating a copper surface by using a browning liquid medicine to roughen the copper surface and facilitate the copper surface to absorb laser energy, and then processing a blind hole designed in the copper-clad plate by using laser ablation; forming electrical connection between the blind hole and the surface of the copper-clad plate by using a chemical copper deposition method so as to facilitate electroplating, and then filling electroplating copper in the blind hole by using a vertical continuous electroplating line; and (3) pasting dry films on the surfaces of two opposite sides of the copper-clad plate, sequentially completing exposure and development operation, covering the dry films and protecting the required circuit part, and developing and removing the dry films corresponding to the non-circuit part. And then, removing the copper layer corresponding to the non-circuit part by using etching liquid, and removing the dry film on the surface of the plate after etching to finish the pattern transfer of the third layer and the fourth layer. An automated optical inspection machine is then used to inspect the quality of the circuit board. And carrying out first pressing, and pressing and adding layers according to the stacked structure of the copper foil, the prepreg, the base material, the prepreg and the copper foil in sequence to form four layers of plates, namely a second layer to a fifth layer. And repeating the steps before the first pressing, and carrying out pattern transfer and quality inspection on the surfaces of the second layer and the fifth layer. And performing second pressing, and pressing and adding layers according to the laminated structure of the carrier copper foil, the prepreg, the multilayer base material obtained by the first pressing, the prepreg, the copper foil and the carrier copper foil in sequence to form six layers of plates, namely the first layer to the sixth layer. And the copper foil during the second lamination needs to be laminated by using an ultrathin copper foil, a carrier copper foil is used for supporting in order to prevent the copper foil from wrinkling during lamination, and the carrier copper foil needs to be peeled off after lamination is finished, wherein the thickness of the carrier copper foil is larger than that of the copper foil. The ultra-thin copper foil of first layer and sixth layer carries out brown ization and laser drilling operation, pastes dry film, exposure, development operation to the substrate after drilling, and the dry film that will make the circuit position is got rid of, and the position that does not need to make the circuit still is covered by the dry film, and wherein the corresponding hole dish of blind hole and drill way side is in the position and also needs to use the dry film to cover. Performing first electroplating operation on the developed substrate, wherein the first electroplating operation is mainly to electroplate and thicken the pattern circuit which is not covered by the dry film to form a circuit pattern with the thickness required by the thin copper circuit; and removing all dry films after the electroplating is finished. And then, a compact thin copper layer is formed on the wall of the blind hole by using a chemical copper deposition mode, so that the blind hole is electrically connected with the copper layer on the board surface, and the subsequent copper plating operation is facilitated. The thickness of the conventional copper deposition is 0.3-0.5 μm, and the thickness of the copper deposition is controlled to be 0.8-1 μm in this embodiment, so as to ensure the reliability of the electrical connection in the blind hole during the subsequent pattern transfer. And carrying out dry film pasting, exposure and development operations on the base material after copper deposition again, removing the dry films at the position where the thick copper circuit needs to be manufactured and the positions of the blind holes and the hole openings of the blind holes and the hole plates corresponding to the hole openings, carrying out secondary electroplating operation on the base material after development, filling the blind holes in the base material with electroplating copper, and thickening the area of the thick copper circuit which is not covered by the dry films together to form the copper thickness required by the thick copper circuit. And removing all dry films after finishing electroplating hole filling and pattern thickening. It should be noted that, during the second pattern transfer, the pattern pre-treatment closes the treatment section with a large influence on the copper surface, such as the grinding plate, so as to prevent the copper layer deposited in the blind hole from being removed and affecting the post-process electroplating, and the pre-treatment can be performed in a mode with a small influence on the copper surface, such as acid washing. Wherein, the dry film used for the second pattern transfer is thicker than the dry film used for the first pattern transfer. The first pattern line transfer can use a dry film with the thickness less than or equal to 25 mu m, the second pattern transfer can select a dry film with the proper thickness according to a copper layer to be thickened, and a vacuum film sticking machine is used for sticking the dry film. After the thin copper circuit and the thick copper circuit are electroplated and thickened, etching liquid medicine is used for etching and removing base copper (including a copper layer deposited on the surface of the base copper in a copper deposition process) formed by the copper foil in a short time, and the circuit structure on the surface of the board is protected from being damaged to the maximum extent. After the rapid etching, a thin copper circuit and a thick copper circuit are formed on the surface of the plate. Solder resist ink is printed on the board surface, and a copper layer which does not need to be exposed except a bonding pad is protected. And forming component symbols, characters or other marks on the board surface by using printing ink with a color different from that of the solder resist ink, usually white ink, and using a silk-screen printing or jet printing mode. An oxidation resistant layer, such as OSP or gold or tin spray, is formed on the pads not covered by the solder mask to protect the exposed copper surface from oxidation prior to final soldering. And milling and routing the production board into a specified size according to actual requirements, and finishing production.
The present invention is not intended to be limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features herein disclosed.
Claims (10)
1. A method for manufacturing a step circuit is characterized by comprising the following steps:
manufacturing a substrate, wherein the substrate comprises a base material and copper foil layers arranged on two opposite sides of the base material;
drilling a blind hole on the copper foil layer on one side, wherein the blind hole penetrates through the copper foil layer on one side and the base material and is communicated with the copper foil layer on the other side;
performing pattern transfer once, namely performing pattern transfer once on the surfaces of the copper foil layers on the two sides, and performing copper plating operation once to form a thin copper circuit and a thick copper circuit with first preset thicknesses at the preset thin copper circuit and the preset thick copper circuit;
conducting treatment on the blind hole;
secondary pattern transfer, namely performing secondary pattern transfer on the thick copper circuit with the first preset thickness, and performing secondary copper plating operation to form a thick copper circuit with a second preset thickness at the position of the preset thick copper circuit;
and etching the copper foil layer, and quickly etching the copper foil layer to obtain the step circuit.
2. The method of claim 1, wherein: the thickness of the copper foil layer is less than 12 μm.
3. The method of claim 2, wherein: the thickness of the copper foil layer is 3-9 μm.
4. The method for manufacturing a ladder circuit according to claim 1, wherein the step of transferring the pattern at one time comprises the steps of:
adhering first dry films to the surfaces of the copper foil layers on the two sides, wherein the first dry films cover the hole openings of the blind holes; carrying out exposure and development operation for one time to remove the first dry film at the position of a preset thin copper circuit and the position of a preset thick copper circuit; then, carrying out copper plating operation once to form a thin copper circuit and a thick copper circuit with first preset thickness at the preset thin copper circuit and the preset thick copper circuit; and then removing the first dry film.
5. The method of claim 4, wherein: the secondary pattern transfer comprises the following specific steps:
attaching second dry films to the surfaces of the copper foil layers on the two sides, wherein the second dry films cover the hole opening of the blind hole, the position of the preset thin copper circuit and the position of the preset thick copper circuit; carrying out secondary exposure and development operation to remove the second dry film at the preset thick copper circuit and the hole of the blind hole; then carrying out secondary copper plating operation to form a thick copper circuit with a second preset thickness at the position of the preset thick copper circuit, wherein the blind hole is filled with a copper layer; and then removing the second dry film.
6. The method of claim 5, wherein: the thickness of the first dry film is less than the thickness of the second dry film.
7. The method of claim 1, wherein the step circuit is formed by attaching second dry films to the predetermined thin copper circuit and the surfaces of the copper foil layers at two sides thereof by:
and pasting the second dry film by using a vacuum film pressing machine.
8. The method for manufacturing a ladder circuit according to claim 1, wherein the specific method of the blind hole electrical conduction treatment is:
and conducting treatment on the blind holes by using a chemical copper deposition method, a black hole process or a graphene process.
9. The method for fabricating a ladder circuit according to claim 1, wherein in the step of drilling the blind via hole in the copper foil layer on one side:
and drilling the blind hole by a machining method of laser ablation.
10. A circuit board, characterized by: the wiring board is formed with a ladder circuit, which is produced by the method for producing a ladder circuit according to any one of claims 1 to 9.
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| CN202111318312.3A CN114222434B (en) | 2021-11-09 | 2021-11-09 | Manufacturing method of ladder circuit and circuit board |
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| CN202111318312.3A CN114222434B (en) | 2021-11-09 | 2021-11-09 | Manufacturing method of ladder circuit and circuit board |
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| CN114222434B CN114222434B (en) | 2023-06-02 |
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| CN114928945A (en) * | 2022-05-27 | 2022-08-19 | 珠海达汉电子科技有限公司 | Manufacturing process of superfine circuit printed circuit board |
| CN114959820A (en) * | 2022-05-25 | 2022-08-30 | 景旺电子科技(龙川)有限公司 | Manufacturing method of flexible circuit board with fine circuit and flexible circuit board |
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| CN114959820A (en) * | 2022-05-25 | 2022-08-30 | 景旺电子科技(龙川)有限公司 | Manufacturing method of flexible circuit board with fine circuit and flexible circuit board |
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| CN114222434B (en) | 2023-06-02 |
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