CN115250585A - Manufacturing method of circuit board - Google Patents

Abstract

The application discloses a method for manufacturing a circuit board. The manufacturing method of the circuit board comprises the following steps: preparing a substrate; arranging a conductive circuit layer on the surface of at least one side of the substrate, wherein the conductive circuit layer comprises a plurality of conductive circuits arranged at intervals; filling insulating materials in gaps formed by a plurality of conductive circuits in the same conductive circuit layer to form an insulating filling layer; the substrate, the conductive circuit layer and the insulation filling layer form a sub-board; the surface of one side, far away from the substrate, of the insulating filling layer is flush with the surface of one side, far away from the substrate, of the conducting circuit layer; and at least two sub-boards are stacked and fixedly connected to form the mother board. The cavity problem generated during the lamination of the mother board can be reduced by the scheme; the thickness uniformity of the mother board is improved.

Description

Manufacturing method of circuit board

Technical Field

The application belongs to the technical field of printed circuit board processing, and particularly relates to a manufacturing method of a circuit board.

Background

In the field of Printed Circuit Board (PCB) production, a daughter board can be prepared first, and a copper layer can be disposed on the daughter board. For the existing PCB, it is usually necessary to stack a plurality of sub-boards on one side. And the adjacent two layers of daughter boards can be subjected to hot-pressing by adopting a prepreg so as to realize fixed connection.

However, for some PCB, when high-speed high-frequency signal transmission is performed, a high-speed high-frequency prepreg is generally required, and the high-speed high-frequency prepreg generally has the characteristics of high viscosity and poor fluidity. With the increase of the number of layers of the daughter boards, if the gap between two adjacent conductive circuits on the daughter boards is large, when the multilayer daughter boards are laminated, the problems of internal cavities of the circuit board, or uneven thickness of the circuit board, influence on the reliability, impedance and the like of the circuit board are easily caused.

Disclosure of Invention

The present application provides a method for manufacturing a circuit board to solve the above technical problems.

In order to solve the technical problem, the application adopts a technical scheme that: provided is a method of manufacturing a circuit board, including:

preparing a substrate;

arranging a conductive circuit layer on the surface of at least one side of the substrate, wherein the conductive circuit layer comprises a plurality of conductive circuits arranged at intervals;

filling insulating materials in gaps formed by a plurality of conductive circuits in the same conductive circuit layer to form an insulating filling layer; the substrate, the conductive circuit layer and the insulating filling layer form a daughter board; the surface of the insulating filling layer far away from the substrate is flush with the surface of the conducting circuit layer far away from the substrate

And at least two sub-boards are stacked and fixedly connected to form the mother board.

Optionally, the step of filling an insulating material in the gaps formed by the plurality of conductive lines to form an insulating filling layer includes:

arranging an insulating material on one side of the conductive circuit layer, which is far away from the substrate, and partially filling the insulating material into gaps formed by a plurality of conductive circuits so as to form an insulating layer;

and removing the part of the insulating layer, which is positioned on the surface of one side of the conductive circuit layer far away from the substrate.

Optionally, the step of removing the part of the surface of the insulating layer on the side of the conductive circuit layer away from the substrate includes:

and removing the part of the surface of the insulating layer, which is positioned on one side of the conductive circuit layer far away from the substrate, by a mechanical processing or laser burning mode.

Optionally, a side of the conductive line layer away from the substrate is covered with an insulating material, and the insulating material is partially filled into gaps formed by the plurality of conductive lines, so that the step of forming the insulating layer includes:

preparing an insulating unit including a laminate sheet and an insulating material disposed at one side of the laminate sheet;

covering the insulating unit on one side of the conducting circuit layer far away from the substrate; so that the insulating material covers one side of the conductive circuit layer far away from the substrate; and the laminated sheet is positioned on one side of the insulating material far away from the substrate;

and laminating the insulating units so that the insulating materials are partially filled into gaps formed by the conductive lines.

Optionally, after the step of laminating the insulating unit so that the insulating material is partially filled into the gaps formed by the plurality of conductive lines, and before the step of removing the part of the insulating layer on the surface of the conductive line layer on the side away from the substrate, the method further includes:

the laminate is removed.

Optionally, the laminated sheet is a metal sheet, and the step of removing the laminated sheet includes:

and etching and removing the laminated sheet.

Optionally, the step of disposing a conductive circuit layer on at least one side surface of the substrate includes:

arranging a conductive metal layer on at least one side surface of the substrate;

and etching the conductive metal layer to form the conductive circuit layer.

Optionally, the step of stacking and fixedly connecting at least two daughter boards to form a motherboard includes:

an adhesive sheet is arranged between two adjacent daughter boards;

and hot-pressing the at least two sub-boards and the bonding sheet to form the mother board.

Optionally, after the step of hot-pressing the at least two sub-boards and the adhesive sheet to form the mother board, the method further includes:

and a via hole is formed in the motherboard and is used for electrically connecting at least two preset conductive circuit layers in the motherboard.

Optionally, solder resist ink is disposed on the conductive circuit layer on the surface layer of the motherboard.

The beneficial effect of this application is: the technical scheme of this application fills up the clearance that many conducting circuits in this conducting circuit layer formed through the insulating filling layer that adopts thickness and conducting circuit layer the same to can be so that when multilayer daughter board lamination, avoid appearing the inside cavity of circuit or thick uneven problem of medium thickness of board, thereby can improve the reliability of circuit board, improve the thickness homogeneity of circuit board.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings used in the description of the embodiments are briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without inventive efforts, wherein:

fig. 1 is a schematic flow chart illustrating an embodiment of a method for manufacturing a circuit board according to the present application;

fig. 2a to fig. 2e are schematic flow charts of another embodiment of a method for manufacturing a circuit board provided by the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that if directional indications (such as up, down, left, right, front, back, 8230; \8230;) are referred to in the embodiments of the present application, the directional indications are only used to explain the relative positional relationship between the components, the motion situation, etc. in a specific posture (as shown in the attached drawings), and if the specific posture is changed, the directional indications are correspondingly changed.

In addition, if there is a description relating to "first", "second", etc. in the embodiments of the present application, the description of "first", "second", etc. is for descriptive purposes only and is 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 at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present application.

Referring to fig. 1, fig. 1 is a schematic flow chart illustrating a method for manufacturing a circuit board according to an embodiment of the present disclosure.

The manufacturing method of the circuit board comprises the following steps:

s110: a substrate is prepared.

In this step, the substrate may be made of an insulating material, for example, the substrate may be made of a resin material. Or the reinforced material can be soaked with resin adhesive and is prepared by the processes of drying, cutting, overlapping and the like, thereby improving the strength of the substrate.

S120: a conducting circuit layer is arranged on at least one side surface of the substrate and comprises a plurality of conducting circuits arranged at intervals.

When the preparation of the substrate is completed, a conductive circuit layer may be disposed on the surface of the substrate. The conductive line layer may include a plurality of conductive lines disposed at intervals. The plurality of conductive lines arranged at intervals can form a preset conductive pattern.

The conductive line layer may be formed by providing a conductive layer on the substrate and then etching the conductive layer. The conductive circuit layer may be made of, but not limited to, copper, aluminum, iron, nickel, gold, silver, platinum group, chromium, magnesium, tungsten, molybdenum, lead, tin, indium, zinc, or alloys thereof.

S130: filling insulating materials in gaps formed by a plurality of conductive circuits in the same conductive circuit layer to form an insulating filling layer; the substrate, the conductive circuit layer and the insulating filling layer form a daughter board; the surface of one side, far away from the substrate, of the insulating filling layer is flush with the surface of one side, far away from the substrate, of the conducting circuit layer.

After step S120 is completed, an insulating filling layer may be further disposed, wherein the insulating filling layer may be filled in the gaps formed by the plurality of conductive lines. One side of the insulating filling layer can be attached to the surface of the substrate, and the other side surface of the insulating filling layer can be flush with the surface of the conducting circuit far away from the substrate.

That is, in this embodiment, the plurality of conductive traces may be disposed on the surface of one side of the substrate at intervals, and the insulating filling layer may fill other areas of the surface of the substrate where no conductive trace is disposed, and the thickness of the insulating filling layer may be equal to that of the conductive trace layer.

The gaps formed by the conductive lines can include a gap between two adjacent conductive lines and a region between the outermost conductive line and the edge of the substrate.

After the conductive circuit layer and the insulating filling layer are arranged on the substrate, the conductive circuit layer and the insulating filling layer can form a daughter board.

S140: and at least two sub-boards are stacked and fixedly connected to form the mother board.

In this step, at least two daughter boards may be further stacked and fixedly connected to form a motherboard. Thus, a multilayer circuit board having a plurality of conductive wiring layers can be formed.

Furthermore, at least two layers of conductive circuits arranged on different layers in the motherboard can be electrically connected through the conductive holes by forming the corresponding conductive holes on the motherboard, so that the multiple layers of conductive circuits in the multilayer circuit board can be used for forming a preset functional circuit.

Therefore, according to the scheme of the embodiment, the gaps formed by the multiple conducting circuits in the conducting circuit layer are filled and leveled by the insulating filling layer with the same thickness as the conducting circuit layer, so that when the multiple layers of sub-boards are laminated, the problem of inner cavities of the circuit or uneven medium thickness of the board can be avoided, the reliability of the circuit board can be improved, and the thickness uniformity of the circuit board can be improved.

In this embodiment, the insulating filling layer may be formed by directly filling an insulating material (for example, a liquid insulating material may be injected) into the gap formed by the plurality of conductive line layers, so that the insulating material fills and levels the gap; or in other embodiments, the insulating filling layer may be formed by using an insulating sheet having a thickness equal to that of the conductive circuit layer and matching with the shape of the substrate, and removing a region corresponding to the conductive circuit layer on the insulating sheet, thereby forming a window having a conductive pattern matching with the conductive circuit layer, and then covering the insulating sheet on the substrate, so that the insulating sheet is fixedly connected to the substrate, and at this time, the plurality of conductive circuits in the conductive circuit layer may be filled into the window. At this time, each side of the conductive circuit layer and the insulation sheet is connected with the substrate, and each other side of the conductive circuit layer and the insulation sheet is arranged in parallel.

Alternatively, in another embodiment, an insulating sheet may be disposed on the substrate, a window matched with the conductive pattern formed by the conductive line layer is opened on the insulating sheet, and then a plurality of conductive lines are formed in the window. Similarly, at this time, each side of the conductive circuit layer and the insulation sheet is connected to the substrate, and each other side of the conductive circuit layer and the insulation sheet is arranged in parallel.

Alternatively, in other embodiments, the insulating material may be covered on the side of the conductive circuit layer away from the substrate by using a thermal compression method, and then a part of the insulating material is removed, so as to form an insulating filling layer that only fills gaps formed by the plurality of conductive circuits.

In particular, please refer to fig. 2 a-2 e. Fig. 2 a-2 e are schematic flow charts of another embodiment of the circuit board manufacturing method provided in the present application.

1. A substrate is prepared, and a conductive line layer is formed on the substrate.

Please refer to fig. 2a. The substrate 210 may be formed of an insulating material. For example, the substrate 210 may be formed of a high-speed low-loss insulating material, so that the finally formed circuit board may perform high-speed high-frequency signal transmission.

The number of the conductive trace layers 220 may be one layer, which may be disposed on one side surface of the substrate 210. Alternatively, the number of the conductive trace layers 220 may also be one, and two conductive trace layers 220 may be respectively disposed on two opposite sides of the substrate 210.

In this step, for example, the substrate 210 includes conductive trace layers 220 on two opposite sides. The conductive trace layers 220 on two opposite sides of the substrate 210 may include a plurality of conductive traces 221 arranged at intervals.

The conductive lines 221 disposed at intervals may be formed by disposing a conductive metal layer on the surface of the substrate 210 and then patterning the conductive metal layer.

2. An insulating layer is formed on a substrate.

Please refer to fig. 2b. In this step, an insulating material may be disposed on a side of the conductive trace layer 220 away from the substrate 210, and the insulating material may partially fill gaps formed by the conductive traces 221, so as to form the insulating layer 230.

In this step, the insulating material may be a prepreg. The insulating layer 230 may be formed by laminating a laminating sheet 240 on the side of the conductive trace layer 220 away from the substrate 210.

Wherein the prepreg may constitute a separate member with the laminate 240, respectively. When performing the lamination, a prepreg may be first placed on the surface of the conductive trace layer 220 away from the substrate 210, and then the lamination sheet 240 may be placed on the surface of the prepreg away from the conductive trace layer 220.

The laminate 240, the prepreg, the conductive trace layer 220, and the substrate 210 are heated and pressed to form the insulating layer 230. The insulating layer 230 includes an insulating filling layer 231 disposed in the gap formed by the conductive traces 221, and an insulating covering layer 232 disposed on a surface of the conductive trace layer 220 away from the substrate 210.

Alternatively, the insulating material may be disposed on the laminated sheet 240, and the prepreg is disposed on the surface of the conductive trace layer 220 on the side away from the substrate 210, and then the laminated sheet 240, the prepreg, the conductive trace layer 220, and the substrate 210 are heated and pressed together, so that the insulating layer 230 may be formed.

Wherein, optionally, the laminated sheet 240 may be a hard insulating sheet; alternatively, the laminate 240 may be a metal sheet, such as a copper sheet.

3. The laminate was removed.

Referring to fig. 2c, after the lamination process is completed to form the insulating layer 230, the laminate 240 may be further removed.

Wherein, when the laminated sheet 240 is a metal sheet, the laminated sheet 240 can be removed by etching.

When the laminate 240 is a rigid insulating sheet, it can be removed by machining or laser ablation.

4. And forming an insulating filling layer.

Please refer to fig. 2d. In this step, the insulating cover layer 232 may be entirely removed, so that only the insulating filling layer 231 may remain in the insulating layer 230. And the conductive trace layer 220 covered by the insulating covering layer 232 is exposed.

At this time, the insulating filling layer 231 and the conductive trace layer 220 may be disposed on one side surface of the substrate 210, and the insulating filling layer 231 and the conductive trace layer 220 have equal thickness. That is, one side of the insulating filling layer 231 and one side of the conductive trace layer 220 are connected to one side surface of the substrate 210; the other sides of the insulating fill 231 and the conductive trace 220 may be in the same plane and disposed flush.

Wherein the insulating cover layer 232 can be removed by machining (e.g., mechanically grinding, polishing, shoveling, etc.); or can be removed by laser burning. The remaining portion of the insulating layer 230 is an insulating filling layer 231.

In the solution in this step, an insulating material may be filled in the gap of the conductive trace layer 220, so that a plane is formed on a side of the conductive trace layer 220 and a side of the insulating filling layer 231 away from the substrate 210. At this time, the substrate 210, the conductive line layer 220, and the insulating filling layer 231 may constitute the sub-board 201 as a whole.

5. At least two daughter boards are arranged in a stacked mode and fixed to form a mother board.

Referring to fig. 2e, in this step, at least two layers of daughter boards 201 may be laminated and fixed to form a mother board by using a lamination process. Specifically, a plurality of sub-boards 201 may be sequentially stacked, and an adhesive sheet 202 may be disposed between two adjacent sub-boards 201, so as to form a structure in which the plurality of sub-boards 201 and the adhesive sheet 202 are sequentially and alternately stacked; then, the entire heat lamination is performed, so that the plurality of sub-boards 201 can be fixedly connected by the adhesive sheet 202, thereby forming a mother board having a plurality of conductive trace layers 220.

In this embodiment, the outermost layer of the motherboard may be provided as the entire conductive layer 203. The conductive layer 203 may be made of a metal material.

After the lamination is completed, a drilling operation may be performed on the mother board to form a through hole that sequentially penetrates the multi-layer sub board 201, and then a metal plating layer may be formed by plating an inner wall of the through hole, so that a conductive through hole may be formed. Wherein the conductive vias can electrically connect the multiple conductive trace layers 220 in the motherboard through the metal plating.

Further, the metal plating layer in the partial hole section in the conductive through hole is removed by performing reaming processing on the conductive through hole, so that a back drilling hole can be formed, and the specified at least one conductive circuit layer 220 in the motherboard can be electrically connected with the conductive layer 203 on the surface layer by forming the back drilling hole.

Furthermore, by patterning the conductive layer 203 on the surface layer of the motherboard, a plurality of conductive traces 221 can be formed on the conductive layer 203, so as to form the conductive trace layer 220 having the same function as that described above. So that the multiple conductive circuit layers 220 in the motherboard can be used to form predetermined functional circuits.

Further, after the patterning process is performed on the conductive layer 203 on the surface layer of the motherboard, the setting of solder resist ink may be performed on the conductive circuit layer 220 formed on the surface layer of the motherboard, so that the conductive circuit layer 220 on the surface layer of the motherboard may be protected.

In summary, the present disclosure provides a method for manufacturing a circuit board. The gaps formed by the conductive lines in the conductive line layer are filled and leveled by the insulating filling layer with the same thickness as the conductive line layer, so that the problem of uneven thickness of the inner holes or the board thickness medium thickness of the circuit can be avoided when the multiple layers of sub-boards are laminated, the reliability of the circuit board can be improved, and the thickness uniformity of the circuit board can be improved.

The above description is only an example of the present application, and is not intended to limit the scope of the present application, and all equivalent structures or equivalent processes performed by the present application and the contents of the attached drawings, which are directly or indirectly applied to other related technical fields, are also included in the scope of the present application.

Claims (10)

1. A method of manufacturing a circuit board, comprising:

preparing a substrate;

arranging a conductive circuit layer on the surface of at least one side of the substrate, wherein the conductive circuit layer comprises a plurality of conductive circuits arranged at intervals;

filling insulating materials in gaps formed by a plurality of conductive circuits in the same conductive circuit layer to form an insulating filling layer; the substrate, the conducting circuit layer and the insulating filling layer form a sub-board; the surface of one side, far away from the substrate, of the insulating filling layer is flush with the surface of one side, far away from the substrate, of the conductive circuit layer;

and at least two sub-boards are stacked and fixedly connected to form the mother board.

2. The method for manufacturing a circuit board according to claim 1, wherein the step of filling an insulating material in the gaps formed by the plurality of conductive lines to form an insulating filling layer comprises:

arranging an insulating material on one side of the conductive circuit layer, which is far away from the substrate, and partially filling the insulating material into gaps formed by a plurality of conductive circuits so as to form an insulating layer;

and removing the part of the surface of the insulating layer, which is positioned on one side of the conductive circuit layer far away from the substrate.

3. The method for manufacturing a circuit board according to claim 2, wherein the step of removing the portion of the surface of the insulating layer on the side of the conductive line layer away from the substrate includes:

and removing the part of the surface of the insulating layer, which is positioned on one side of the conductive circuit layer far away from the substrate, by a mechanical processing or laser burning mode.

4. The method according to claim 2, wherein the step of forming an insulating layer by covering an insulating material on a side of the conductive trace layer away from the substrate and partially filling the insulating material into gaps formed by the plurality of conductive traces comprises:

preparing an insulating unit including a laminate sheet and an insulating material disposed at one side of the laminate sheet;

covering the insulating unit on one side of the conducting circuit layer far away from the substrate; so that the insulating material covers one side of the conductive circuit layer far away from the substrate; and the laminated sheet is positioned on one side of the insulating material far away from the substrate;

and laminating the insulating unit so that the insulating material is partially filled into gaps formed by the conductive lines.

5. The method of manufacturing a circuit board according to claim 4,

the step of laminating the insulating units to enable the insulating material to be partially filled into gaps formed by the conductive circuit layers and before the step of removing the part, located on the surface of the conductive circuit layer, of the insulating layer on the side far away from the substrate further comprises:

the laminate is removed.

6. The method for manufacturing a circuit board according to claim 5, wherein the laminated sheet is a metal sheet, and the step of removing the laminated sheet includes:

and etching and removing the laminated sheet.

7. The method for manufacturing a circuit board according to any one of claims 1 to 6, wherein the step of providing a conductive line layer on at least one side surface of the substrate includes:

arranging a conductive metal layer on at least one side surface of the substrate;

and etching the conductive metal layer to form the conductive circuit layer.

8. The method of claim 7, wherein the step of fixedly attaching at least two daughter boards in a stacked configuration to form a motherboard comprises:

an adhesive sheet is arranged between two adjacent daughter boards;

and hot-pressing the at least two sub-boards and the bonding sheet to form the mother board.

9. The method of manufacturing a circuit board according to claim 8, wherein after the step of thermocompressing the at least two sub-boards and the adhesive sheet to form the mother board, the method further comprises:

and a via hole is formed in the motherboard and is used for electrically connecting at least two preset conductive circuit layers in the motherboard.

10. The method of manufacturing a circuit board according to claim 9,

and solder resist ink is arranged on the conductive circuit layer on the surface layer of the motherboard.

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