KR20040036779A - Method of manufacturing capacitor-embedded printed circuit board - Google Patents

Abstract

PURPOSE: A method for fabricating a capacitor-embedded PCB(Printed Circuit Board) is provided to obtain the uniform thickness of the dielectric layer and enhance the capacitance by forming a capacitor layer with RCC(Resin Coated Copper foil). CONSTITUTION: A capacitor-laminated layer is formed on an entire surface of an inner laminated layer. The capacitor-laminated layer is formed with RCC. An unnecessary part and a dielectric layer are sequentially removed from a conductive layer of the capacitor-laminated layer. A protective layer is formed thereon in order to protect the necessary part of the conductive layer. The exposed conductive layers and the protective layer are sequentially removed from the capacitor-laminated layer and the inner laminated layer. A capacitor layer is formed by laminating a first electrode plate of the capacitor-laminated layer, a second electrode plate of the inner laminated layer, and the dielectric layer therebetween. A via-hole and a through-hole are formed on the first electrode plate of the capacitor-laminated layer. A plating process for the via-hole is performed.

Description

Capacitor-embedded printed circuit board manufacturing method {METHOD OF MANUFACTURING CAPACITOR-EMBEDDED PRINTED CIRCUIT BOARD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor-embedded printed circuit board (PCB) in which a capacitor is integrally embedded. The present invention has a high capacitance value and maintains a uniform dielectric film thickness to minimize manufacturing variation. It relates to a capacitor embedded printed circuit board manufacturing technology.

When the passive element is embedded in the printed circuit board, it is possible to reduce the cost of the passive element and reduce the mounting cost according to the passive element mounting. In addition, the noise and inductance generated in the solder joint of the passive element can be significantly reduced, and at the same time, by converting the passive element into an embedded type, the area of the printed circuit board can be reduced, thereby contributing to cost reduction and product miniaturization.

On the other hand, the technology for mounting the embedded capacitor on the printed circuit board is described in the Republic of Korea Patent No. 227,528. The built-in capacitor manufacturing technology disclosed in Korean Patent Registration No. 227,528 uses a laminate in which an insulator having a thickness of 1 to 2 mils (25 to 50 μm) is sandwiched between copper foils, but the laminate is to serve as a capacitor. Since the epoxy resin is used as the insulator formed in the middle, the capacity of the capacitor is small.

1 is a view schematically showing a method for manufacturing a capacitor-embedded printed circuit board according to the prior art. That is, referring to Figure 1, the prior art disclosed in Korean Patent No. 227,528 (International Application No. PCT / US90 / 04777) is a dielectric material inserted between the separated conductive material films 10a, 10c and 12a, 12c. The films 10b and 12b are stacked on each other to form the capacitor laminates 10 and 12, and are stacked together with the stack 11 on which a plurality of elements are mounted to form a printed circuit board with a capacitor.

However, in the case of the multilayer capacitor according to the related art shown in FIG. 1, in order to increase the capacitance, the thicknesses of the dielectric material films 10b and 12b should be thinned. In this case, the strength of the multilayer capacitors 10 and 12 deteriorates. As a result, in addition to the disadvantage of the capacitor capacitance mentioned above, there is a problem in that the conveyor transfer operation becomes difficult in the printed circuit board manufacturing process step.

Accordingly, a first object of the present invention is to provide a capacitor embedded printed circuit board manufacturing technology having a large capacitance value.

A second object of the present invention is to provide a capacitor-embedded printed circuit board manufacturing technique with no manufacturing variation by maintaining the thickness of the dielectric material film constituting the laminated capacitor in addition to the first object.

1 is a schematic view showing a capacitor embedded printed circuit board manufacturing method according to the prior art.

2A-2I illustrate a process of manufacturing a capacitor embedded printed circuit board according to a preferred embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

20: inner layer laminate

20a, 20b: conductive film

30: capacitor laminate

30a: conductive film

30b: dielectric material film

40: copper foil

50: shield

60: RCC

70: blind via hole

80: through hole

90 plating

In order to achieve the above object, the present invention is a method for forming a capacitor-embedded printed circuit board by laminating a capacitor laminate on the inner layer laminate in which the electrode pattern is formed, the pressure of the copper laminate remains on the entire surface of the inner layer laminate In the process of laminating the capacitor laminate plate, the capacitor laminate plate provides a method for manufacturing a capacitor-embedded printed circuit board, characterized in that the dielectric material film is formed of a conductive film coated on one surface.

Hereinafter, a method of manufacturing a capacitor embedded printed circuit according to the present invention will be described in detail with reference to the accompanying drawings, FIGS. 2A to 2I.

As described above, since the dielectric film thickness of the printed circuit-embedded capacitor according to the prior art is about 50 μm and the dielectric constant of the dielectric film is about 4.0, the capacitance per unit area is very low, such as 0.8 pF / mm 2. However, since the present invention forms a copper foil after lamination using a resin coated copper foil (RCC) as a dielectric layer, a thin dielectric film thickness of 25 μm or less can be easily handled.

Moreover, since the insulating layer of the RCC uses a material having a high dielectric constant, high capacitance can be expected. As a preferred embodiment of the present invention, when a resin having a dielectric constant of about 21 μm and having a dielectric constant of about 21 is used, a high capacity capacitor having 16.8 pF / mm 2 per unit area may be embedded in a printed circuit board. Furthermore, the present invention proposes a method of removing unnecessary copper foil after laminating the RCC to the inner layer, thereby preventing the non-uniformity in the dielectric film thickness that may occur during the pressure lamination of the capacitor laminate to the inner layer laminate. The result is a uniform capacitance with low dispersion.

2A to 2I illustrate a process of manufacturing a capacitor embedded printed circuit board according to a preferred embodiment of the present invention. Referring to FIG. 2A, an inner layer laminate 20 of a semifinished product state in which a circuit ground or the like is formed in the inner layer is fabricated.

Referring to FIG. 2B, a capacitor laminate 30 is laminated on the inner laminate 20, and an inner layer is left with a conductive film, i.e., copper foils 20a, 20c, on the entire surface of the capacitor laminate 30 due to the pressing force. As a result of the deformation of the resin 30b, a thickness deviation is prevented from occurring.

As a preferred embodiment of the present invention, the capacitor laminate 30 is formed of a conductive film 30a and a dielectric material film 30b, more preferably a resin coated copper foil (RCC) may be used. Subsequently, as shown in FIG. 2C, the copper foil 40 of unnecessary portions can be removed by corrosion, and the dielectric film layer 30b can be selectively removed using a CO 2 laser.

In addition, referring to FIG. 2B, a protective film 50 is covered by using a dry film or an etching resist corresponding thereto to protect the copper foil 30a of the required portion. Then, as shown in Fig. 2E, the unnecessary copper foil on the surface and the inner layer is removed with a corrosion solution. Subsequently, the dry film used as the protective film 50 can be peeled off.

Then, as shown in Fig. 2G, the RCC 60 or the copper foil and the prepreg are lined on the upper and lower surfaces of the completed inner layer capacitor layer. Meanwhile, as shown in FIG. 2H, the blind via hole 70 and the through hole 80 are processed by using a conventional PCB method. Next, as shown in FIG. 2I, the hole 70 is conducted through the plating 90 or the like.

The foregoing has outlined rather broadly the features and technical advantages of the present invention to better understand the claims of the invention which will be described later. Additional features and advantages that make up the claims of the present invention will be described below. It should be appreciated by those skilled in the art that the conception and specific embodiments of the disclosed subject matter can be used immediately as a basis for designing or modifying other structures for carrying out similar purposes to the present invention.

In addition, the inventive concepts and embodiments disclosed herein may be used by those skilled in the art as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. In addition, such modifications or altered equivalent structures by those skilled in the art may be variously changed, substituted, and changed without departing from the spirit or scope of the invention described in the claims.

As described above, the present invention forms a capacitor layer using a resin coated copper foil (RCC), unlike the prior art, and because the RCC is lined with copper foil on the entire inner layer, the capacitor dielectric film thickness becomes uneven during the pressure lamination process. Can be prevented. In addition, the present invention can form a capacitor using the RCC can implement a high capacitance, as well as having a mechanical strength can be applied to a general conveyor transfer process without problems.

Claims (5)

A method of forming a capacitor-embedded printed circuit board by laminating a capacitor laminate on an inner layer laminate on which an electrode pattern is formed, and forming a capacitor-embedded printed circuit board, the process of laminating the capacitor laminate in a state in which copper foil remains on the entire surface of the inner layer laminate. And the capacitor laminate is formed of a conductive film coated on one surface of a dielectric material film. The method of claim 1, wherein the capacitor laminate is formed of a resin coated copper foil (RCC). The method of claim 1, wherein the capacitor-embedded printed circuit board is manufactured. Removing the dielectric material film after removing unnecessary portions of the conductive film of the capacitor laminate, in which copper foil is entirely left over the entire surface of the inner layer laminate; Selectively applying a protective film for protecting a necessary portion of the conductive film of the capacitor laminate remaining in the corrosion removal process; Etching away the conductive film of the exposed portion of the conductive film of the capacitor laminate and the conductive film of the inner layer laminate and removing the protective film; Laminating a capacitor layer comprising a conductive film (first electrode plate) of the capacitor laminate and a conductive film (second electrode plate) of the inner layer laminate and a dielectric material film therebetween; And Processing via holes or through holes leading to the first electrode plate of the capacitor, and plating and conducting the via holes in the via holes; Capacitor embedded printed circuit board manufacturing method comprising a. The method of claim 3, wherein the passivation layer is formed using a dry film or an etching resist. 5. The method of claim 4, wherein the conductive film is selectively removed using a CO 2 laser.