KR20090104495A - Method for manufaturing a multy-layered printed circuit board - Google Patents

Abstract

PURPOSE: A manufacturing method of a multi-layered printed circuit board is provided to reduce a manufacturing time of a multi-layered printed circuit board by laminating independently manufactured substrates at a time. CONSTITUTION: A circuit layer is formed on a first substrate(100a). A land and a circuit pattern are formed in one surface or both surfaces of the circuit layer. In a second substrate, a conductive bump is formed on the land of one surface. A bonding layer is formed in both surfaces of an unclad substrate. The unclad substrate includes a through hole. The first substrate, the unclad substrate, and the second substrate are arranged and are laminated.

Description

METHODS FOR MANUFATURING A MULTY-LAYERED PRINTED CIRCUIT BOARD

The present invention relates to a method for manufacturing a multilayer printed circuit board using a batch lamination method. More specifically, multi-layered printing in which an unclad substrate in which an adhesive layer is laminated on both sides of an insulating resin of a C-stage is arranged between laminated substrates, thereby maintaining a constant distance between batch laminated substrates and increasing connection reliability. It relates to a method for manufacturing a circuit board.

Printed Circuit Board (PCB) is made by attaching a thin plate such as copper to one side of phenolic resin insulation board or epoxy resin insulation board, and then etching it according to the wiring pattern of the circuit. It constructs the necessary circuits and makes holes by attaching and mounting the parts.

That is, the printed circuit board electrically connects the components mounted through the wiring pattern, supplies power and the like, and mechanically fixes the components.

Printed circuit boards include single-sided PCBs with wires formed on only one side of the insulated board, double-sided PCBs with wires on both sides, and MLB (Multi Layered Boards) wired in multiple layers. In the past, single-sided PCBs were used because of simple components and simple circuit patterns. However, in recent years, due to increased complexity of circuits and increased demand for high-density and miniaturized circuits, it is common to use double-sided PCBs or MLBs. The present invention relates to a process for producing MLB among them.

MLB has a great advantage that it can significantly increase the wiring density, but there is a difficulty that the manufacturing process is complicated. In particular, since the inner layer is not deformable when the process is completed according to the conventional build-up method, if there is an error in the inner layer, all the finished products become defective. Many inspection devices have been developed and used to prevent such errors in advance.

Hereinafter, a manufacturing method of a printed circuit board including a total of eight circuit layers implemented by a conventional build-up method will be described in detail with reference to FIG. 1.

The build-up method is literally a method of manufacturing a method of forming an inner layer first, and additionally stacking outer layers one by one. More specifically, after stacking an insulating layer on a base substrate on which a predetermined inner layer circuit pattern is formed, A method of stacking a plurality of outer layers by performing an additional masking process.

First, as shown in FIG. 1A, a four-layer core substrate 1 manufactured by a conventional MLB manufacturing method is provided. Thereafter, as shown in FIG. 1B, the insulating material 3 and the copper foil 5 are placed on the upper and lower portions of the core substrate 1, and heated and pressed to form an outer layer. Then, as shown in Figure 1c, for the electrical conduction between the outer layer and the inner layer to form a window for the outer layer copper foil is processed via holes with a laser. Thereafter, as shown in FIG. 1D, fill plating is performed to form the vias 7, and a circuit is formed by a subtractive method. 1E-1G illustrate a process for repeating the above steps to form additional outer circuit layers. The difference is that the plating is performed so as not to fill the inside of the via 7 '. The substrate completed by the above process is shown in FIG. 1G.

As described above, the conventional sequential layer method has been used since fabrication of the core substrate. However, when the sequential layer method is used, a repeated window forming process, a laser processing process, and a plating process are required to form an outer layer, and thus, There is a problem that is difficult to minimize and there is a limit to shorten the time required for the production of the substrate.

In order to compensate for this, a fabrication method of fabricating a circuit layer and an insulating layer through independent processes, and then stacking a plurality of them in parallel is required.

The present invention was created to solve the problems of the prior art as described above, and proposes a manufacturing method of collectively stacking a plurality of substrates manufactured in parallel through independent processes.

According to an aspect of the present invention, there is provided a method of manufacturing a multilayer printed circuit board, the method comprising: (A) providing a first substrate having a circuit layer including lands and circuit patterns on one or both surfaces thereof; (B) providing a second substrate having a circuit layer including lands and circuit patterns on one or both surfaces thereof, and having conductive bumps formed on the lands of one surface; (C) providing an unclad substrate having an adhesive layer on both sides and having a through hole; (D) aligning and stacking the first substrate, the unclad substrate, and the second substrate.

As a preferred feature of the invention, the step (D), (D-1) the unclad laminate by laminating the unclad substrate on the surface of the bump formed on the second substrate so that the bump passes through the through hole. Forming a; And (D-2) aligning and stacking the first substrate and the unclad laminate.

As another preferable feature of the present invention, the unclad substrate is a resin in a fully cured state.

As another preferable feature of the present invention, the adhesive layer is a resin in a semi-cured state.

In another preferred aspect of the present invention, after the step (D), (E) further comprises the step of electrically connecting between the layers by forming and plating through-holes and through-holes for interlayer conduction.

As another preferred feature of the invention, the thickness of the unclad substrate is smaller than the height of the bump.

As another preferred feature of the invention, the step (C), (C-1) laminating an adhesive layer on both sides of the unclad substrate; And (C-2) forming a through hole in the unclad substrate by a drilling process.

As another preferred feature of the invention, the step (D), (D-1) providing a plurality of the second substrate according to the (B); (D-2) providing a plurality of the unclad substrates according to (C); And (D-3) aligning and stacking the first substrate, the plurality of second substrates, and the plurality of unclad substrates.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to this, the terms or words used in this specification and claims are not to be interpreted in a conventional and dictionary sense, and the inventors may appropriately define the concept of terms in order to best describe their own invention. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

According to the method for manufacturing a multilayer printed circuit board of the present invention, by stacking the substrates independently manufactured, the manufacturing time of the multilayer printed circuit board is reduced.

In addition, since the present invention uses an unclad substrate including an insulating resin of the C-stage, the strength of the substrate is improved, and the interlayer distance between the substrates stacked in the batch lamination process can be kept constant. Since the curing time of the insulating layer is not necessary, the time required for the circuit lamination process can be shortened.

Hereinafter, with reference to the accompanying drawings a preferred embodiment of a method for manufacturing a multilayer printed circuit board according to the present invention will be described in detail. Throughout the accompanying drawings, the same or corresponding components are referred to by the same reference numerals, and redundant descriptions are omitted.

2 to 9 are diagrams showing a manufacturing method of a multilayer printed circuit board 10 (see FIG. 9) according to a preferred embodiment of the present invention in the order of process. In this embodiment, a method of manufacturing a multilayer printed circuit board 10 having eight circuit layers is described, but this is exemplary and the present invention is not limited to the number of circuit layers in this embodiment.

In the manufacturing method of the multilayer printed circuit board 10 according to the present embodiment, two types of substrates manufactured by different manufacturing methods are used. FIG. 2 shows a method of manufacturing the substrate disposed at the outermost part in the batch lamination process of the present embodiment, and FIG. 4 shows a method of manufacturing the substrate disposed between the outermost layers in the batch lamination process of the present embodiment. Show in order. In the present specification, for convenience of description, the substrates disposed in the outermost layers during the batch lamination are referred to as "outer layer substrates 100a and 100b", and the substrates disposed between the outermost layers are referred to as "inner layer substrates 200b". However, the present invention is not limited to using only the outer layer substrates 100a and 100b and the inner layer substrate 200b manufactured by the method according to the present embodiment, and it should be understood that a substrate manufactured by another known method may be used. do. In addition, the outer layer substrates 100a and 100b and the inner layer substrate 200b are only names defined for better understanding, and the names are not to be interpreted in any limiting sense. That is, the outer layer substrates 100a and 100b of the present embodiment may be located between other substrates in other embodiments. Hereinafter, the manufacturing method of the board | substrate used by a present Example is described.

2 illustrates a method of manufacturing the outer layer substrate 100a according to the present embodiment, and FIG. 3 shows a state in which a paste bump 90 is printed on a land 150 formed on one surface of the outer layer substrate 100a.

Referring to FIG. 2, a double-sided copper clad laminate (CCL) having a copper foil layer 130 on both sides of an insulating resin 110 is provided (FIG. 2A), and a circuit layer is formed on the copper foil layer 130 to form an outer layer substrate 100a. ) (FIG. 2B). Exposure, development, etching, and inspection are performed to form a circuit layer including the lands 150 and the circuit patterns 170 of the vias 130 on the copper foil layer 130.

The exposure process is a process of forming a pattern image by matching a working film on a dry film coated on the copper foil layer 130, and reacting a monomer with a polymer by cutting a predetermined amount of light into a polymer. to be. The developing step is a step of peeling off a monomer (uncured monomer) part which is not changed into a polymer (photocuring polymer) in the exposure step, that is, a part that is not subjected to light using a chemical. An etching process is a process of removing exposed copper foil of a part other than the part covered with the dry film after a developing process, ie, a part which is not a circuit pattern, with a chemical. Thereafter, the first outer layer substrate 100a of the present embodiment is provided by removing the dry film through the peeling process and inspecting the inner circuit formed through the inspection process.

As shown in FIG. 3, a second outer layer is formed by forming a bump 90 on a land 150 formed on one surface of another first outer layer substrate 100a manufactured as described above, as another outer layer substrate. The board | substrate 100b is produced. The bump 90 is printed by a screen print method. Screen printing is a method of printing the bump 90 through a conductive paste transfer process through a mask in which an opening is formed. The positions of the openings of the mask are aligned, and the conductive paste is applied to the upper surface of the mask. When the conductive paste is pushed using a squeegee or the like, the conductive paste is extruded through the opening and transferred to the land 150. In this case, the bump 90 may be printed on a portion where the land 150 of the circuit layer is formed to be printed in a desired shape and height.

The circuit layers of the outer layer substrates 100a and 100b according to the present exemplary embodiment include lands 150 for conduction with adjacent layers in batch stacking, and the positions of the lands 150 are sufficiently considered in designing a circuit.

Meanwhile, the outer substrates 100a and 100b according to the present embodiment are illustrated as not forming vias for interlayer conduction. However, the outer substrates 100a and 100b are not limited thereto and may be formed using vias for interlayer conduction.

4 shows a process of providing an inner layer base substrate 200a of the present embodiment, and FIG. 5 shows an inner layer substrate 200b having a paste bump 90 formed on a land 250 of one surface of the inner layer base substrate 200a. To show. As shown in Fig. 4, the present embodiment uses an inner layer substrate 200b manufactured in a manner referred to as a so-called "Burried bump interconnection technology" (B2it) technique.

Referring to FIG. 4, a copper plate 230a is provided (FIG. 4A), and a paste bump 290 is printed on the copper plate 230a (FIG. 4B). The process of forming the paste bumps 290 is the same and very similar to that described above, and the detailed description is omitted. After the paste bump 290 is formed, the insulating layer 210 is laminated so that the paste bump 290 penetrates the insulating layer 210 (FIG. 4C). The insulating layer 210 used here is preferably a resin layer in a B-stage state. The B-stage means an intermediate curing step of the resin, and is deformable by heating and pressing a predetermined size or more. Thereafter, the copper foil 230b is laminated on the insulating layer 210 (FIG. 4D). At this time, the bump 290 is connected to the copper foil 230b laminated. Thereafter, a circuit layer including the land 250 and the circuit pattern 270 is formed on the copper plate 230a and the copper foil 230b (FIG. 4E). The process of forming the circuit layer is the same and very similar to that described above with respect to the circuit layer formation of the first outer layer substrate 100a, and thus a detailed description thereof will be omitted. After the formation of the circuit layer, the inner base board 200a used in the present embodiment is completed.

As shown in FIG. 5, the bump 90 is printed on the land 250 formed on one surface of the substrate 200a manufactured according to the above-described process to fabricate the inner layer substrate 200b. The printing method of the bump 90 is the same as described above and extremely similar, and thus will be omitted. In the present embodiment, two such inner substrates 200b are used.

In the above process, the first outer layer substrate 100a, the second outer layer substrate 100b, and the two inner layer substrates 200b are provided. In the present specification, for convenience of description, the substrate on which the bump 90 is not formed is referred to as a "first substrate", and the substrate on which the bump 90 is formed is referred to as a "second substrate". That is, the names of the first substrate and the second substrate are classified based on whether the bump 90 is formed, and it is irrelevant whether the substrate on which the bump 90 is formed is the inner layer substrate 200b or the outer layer substrate 100b. Do. In this embodiment, one first substrate and three second substrates are used.

6 shows a method of manufacturing the unclad substrate 300 used in this embodiment. An insulating resin 310 is provided (FIG. 6A), and an adhesive layer 340 is laminated on both surfaces (FIG. 6B), and a through hole 390 is formed by a drilling process to provide an unclad substrate 300 (FIG. 6C). . The through hole 390 formed in the unclad substrate 300 is formed at a position where the bump 90 of the second substrate is formed. That is, the position of the through hole 390 is determined by the position of the bump 90 of the second substrate. The insulating resin 310 used for the manufacture of the unclad substrate 300 is preferably a C-stage, that is, a resin in a fully cured state, and the adhesive layer 340 is preferably a B-stage resin. In this embodiment, three unclad substrates 300 are used.

Since the unclad substrate 300 according to the present embodiment uses the C-stage insulating resin 310, the interlayer distance between the substrates to be stacked is kept constant in the batch lamination process described later, and curing of the insulating layer interposed between the substrates is performed. The time required for the circuit lamination process can be shortened because no time is required.

FIG. 7 is a diagram illustrating a state in which an unclad substrate 300 is stacked on a surface on which a bump 90 of the second substrate is formed. As a preparatory step for the batch lamination, the unclad substrates 300a and 500b are formed by stacking the unclad substrate 300 on the second substrate such that the bump 90 protrudes through the unclad through holes 390. . That is, in the present embodiment, two unclad laminates 500a (FIG. 7A) formed of the outer layer substrate 100b and two unclad laminates 500b (FIG. 7B) formed of the inner layer substrate 200b are provided. Although this step is not essential, it is preferable to be performed prior to the batch stacking to secure the reliability of the batch stacking described later.

On the other hand, as shown in Figure 7a and 7b, the height of the bump 90 of the present embodiment is larger than the thickness of the unclad substrate 300, the maximum diameter of the bump 90 is a through hole of the unclad substrate 300 It is preferred to be smaller than the diameter of 390.

8 shows a first substrate (outer layer substrate) 100a and three unclad laminates 500b, 500b, 500a arranged for batch lamination.

Referring to FIG. 8, the surfaces on which the bumps 90 are formed do not overlap between the stacked substrates, and the bumps 90 are arranged to be connected to the lands 150 and 250 of the adjacent substrates, and then pressurized by a press. Laminate collectively.

Meanwhile, in the present embodiment, although the first substrate is disposed on the outermost layer, the present invention is not limited thereto, and the first substrate may be located between the unclad laminates 500b.

FIG. 9 is a view illustrating a state in which vias 730 and through vias 710 are additionally formed in the multilayer printed circuit board 10 stacked by the above process.

Further formation of vias 730 and through vias 710 is optional. That is, when the interlayer conductive holes are formed in the outer layer substrates 100a and 100b, the process of forming the vias 730 does not need to be performed, and the through vias 710 are formed on the stacked multilayer printed circuit board 10. It is formed to connect the outermost circuit layer, and the position of the vias 290 and 730 for interlayer conduction of the stacked substrate as shown in FIG. 9 and the bump 90 printed on the second substrate are matched. It should be understood that this may be achieved by the implementation of staggered vias.

On the other hand, the present invention is not limited to the described embodiments, it is apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, such modifications or variations will have to belong to the claims of the present invention.

1 is a view showing a method of manufacturing an eight-layer printed circuit board according to the prior art in the process order.

2 is a view showing a method of manufacturing a first outer layer substrate according to a preferred embodiment of the present invention in the order of process.

3 is a diagram illustrating a second outer layer substrate having conductive bumps formed on one surface of the outer layer substrate of FIG. 2.

4 is a diagram illustrating a method of manufacturing an inner layer base substrate according to a preferred embodiment of the present invention in the order of process.

FIG. 5 is a diagram illustrating an inner layer substrate having conductive bumps formed on one surface of the inner layer base substrate of FIG. 4.

6 is a diagram illustrating a method of manufacturing an unclad substrate according to a preferred embodiment of the present invention in the order of process.

7 illustrates an unclad laminate according to a preferred embodiment of the present invention.

8 shows a first substrate and an unclad laminate arranged in accordance with a preferred embodiment of the present invention.

9 illustrates a multilayer printed circuit board made in accordance with a preferred embodiment of the present invention.

<Description of Major Symbols in Drawing>

10 Multilayer Printed Circuit Board

100a first outer layer substrate 100b second outer layer substrate

110 Outer Board Insulation Resin 130 Outer Board Copper Foil

150 Outer Board Land 170 Circuit Pattern

200a inner layer base board

200b Inner Board 210 Insulation Resin

230a copper plate 230b copper foil

250 Inner Board Land 270 Circuit Pattern

290 Inner Board Bumps 300 Unclad Boards

310 Inner Layer Substrate Insulation Resin 340 Adhesive Layer

390 through hole

500a unclad laminate made of second outer layer substrate

Unclad laminate made of 500b innerlayer substrate

710 Through Via 730 Via

Claims (8)

(A) providing a first substrate having a circuit layer including lands and circuit patterns on one or both surfaces thereof; (B) providing a second substrate having a circuit layer including lands and circuit patterns on one or both surfaces thereof, and having conductive bumps formed on the lands of one surface; (C) providing an unclad substrate having an adhesive layer on both sides and having a through hole; (D) aligning and stacking the first substrate, the unclad substrate, and the second substrate; Method of manufacturing a multilayer printed circuit board comprising a. The method of claim 1, Step (D), (D-1) forming an unclad laminate by stacking the unclad substrate on the bump-formed surface of the second substrate such that the bump passes through the through hole; And (D-2) aligning and stacking the first substrate and the unclad laminate; Method of manufacturing a multilayer printed circuit board comprising a. The method of claim 1, The unclad substrate is a manufacturing method of a multilayer printed circuit board, characterized in that the resin in a fully cured state. The method of claim 1, The adhesive layer is a manufacturing method of a multilayer printed circuit board, characterized in that the resin in a semi-cured state. The method of claim 1, After the step (D), (E) a method for manufacturing a multilayer printed circuit board further comprising the step of forming via and through-holes for interlayer conduction and plating to electrically connect between the layers. The method of claim 1, The thickness of the unclad substrate is smaller than the height of the bump manufacturing method of a multilayer printed circuit board. The method of claim 1, Step (C) is (C-1) laminating an adhesive layer on both sides of the unclad substrate; And (C-2) forming a through hole in the unclad substrate by a drilling process; Method of manufacturing a multilayer printed circuit board comprising a. The method of claim 1, Step (D), (D-1) providing a plurality of the second substrates according to (B); (D-2) providing a plurality of the unclad substrates according to (C); And (D-3) arranging and stacking the first substrate, the plurality of second substrates, and the plurality of unclad substrates.

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