TWI674835B - Printed circuit board and manufacturing method thereof - Google Patents

Abstract

A printed circuit board manufacturing method includes providing a circuit board substrate, processing an opening on the circuit board substrate, electroplating a first plating layer on the circuit board substrate, pressing a copper block into the opening, and flattening. A surface of the substrate of the circuit board is used to form a planarized circuit board surface, a second plating layer is plated on the planarized circuit board surface, and a photosensitive film is formed on the second plating layer. In addition, a printed circuit board is also disclosed here.

Description

Printed circuit board and manufacturing method thereof

The disclosure relates to a printed circuit board and a manufacturing method thereof, and more particularly to a printed circuit board with a heat dissipation function and a manufacturing method thereof.

At present, electronic products are developing in the direction of high performance, high frequency, high speed and thinness, and various electronic related parts are also developing in the direction of multifunction, high speed, multipower and small size. As electronic products have more and more functions, the power they consume is increasing, so that electronic products will generate a lot of heat during operation, which will increase the temperature of electronic products.

Printed circuit boards (PCBs) also face problems with thermal energy control. The printed circuit board is composed of a substrate material connected in a conductive insulating material between the components, and it is not itself a good conductor of heat. Generally, the thermal conductivity λ of a typical substrate material is about 0.2 W / mK. In comparison, copper has a high thermal conductivity of about 390 W / mK. Therefore, in order to reduce the reliability problem caused by the high temperature of electronic products, copper blocks are usually built into the circuit board as a heat dissipation path for electronic components.

However, in the heat dissipation method of the circuit board with copper blocks built in, copper The block is not necessarily matched with the size of the opening between the circuit boards. For example, the side of the copper block is raised, so there will be a gap between the copper block and the circuit board. The gap in it will easily make the solder paste and heat conduction in the circuit board process. The paste flows to the back of the circuit board and affects the efficiency of the electronic product.

In view of this, the embodiments of the present disclosure relate to a printed circuit board with a heat dissipation function and a method for manufacturing the same.

In some embodiments of the present disclosure, a printed circuit board manufacturing method includes the following steps: providing a circuit board substrate, processing an opening in the circuit board substrate, and plating a first plating layer on the circuit board substrate. A copper block is pressed into the opening to flatten the surface of the circuit board substrate to form a flattened circuit board surface, a second plating layer is plated on the flattened circuit board surface, and a photosensitive film is formed On the second plating layer.

In some embodiments of the present disclosure, the above-mentioned manufacturing method further includes patterning the photosensitive film to expose a plurality of grooves of the circuit board substrate, and the grooves include a plurality of grooves around the copper block and the circuit board substrate. At the gap.

In some embodiments of the present disclosure, the above-mentioned manufacturing method further includes electroplating a third electroplating layer and filling the grooves of the substrate of the circuit board.

In some embodiments of the present disclosure, the first plating layer, the second plating layer, and the third plating layer are copper plating layers.

In some embodiments of the present disclosure, the manufacturing method further includes electrically connecting the first plating layer and the copper block.

In another embodiment of the present disclosure, a printed circuit board, It includes a circuit board substrate, a first plating layer, a copper block, a second plating layer, and a patterned photosensitive film. The circuit board substrate has an opening. The first plating layer is formed on the substrate of the circuit board. A copper block is disposed in the opening. The second plating layer is formed on the first plating layer. A patterned photosensitive film is formed on the second plating layer.

In some embodiments of the present disclosure, the above-mentioned circuit board substrate further includes a plurality of grooves, and the patterned photosensitive film exposes the grooves, wherein the grooves include a plurality of areas between the periphery of the copper block and the circuit board substrate. At the gap.

In some embodiments of the present disclosure, the printed circuit board further includes a third electroplated layer, and the grooves are filled in the substrate of the circuit board.

In some embodiments of the present disclosure, the first plating layer, the second plating layer, and the third plating layer are copper plating layers.

In some embodiments of the present disclosure, the first plating layer is electrically connected to the copper block.

It can be known from the foregoing embodiments that the printed circuit board and the manufacturing method provided by the present disclosure can achieve a good heat dissipation effect through electroplating, a planarization process, forming a photosensitive film, and performing a patterning process to form a patterned photosensitive film, and During the flattening process, the ductility of copper itself can be used to help planarize the surface of the circuit board and improve the heat dissipation effect. Therefore, the problem of solder paste and thermal conductive paste flowing to the back of the circuit board during the circuit board process can be improved. Then improve the efficiency of electronic products.

The above is only used to explain the problems to be solved by this disclosure, the technical means to solve the problems and their generated effects, etc. The specific details of this disclosure are described in detail in the following embodiments and related drawings.

100‧‧‧Printed circuit board manufacturing method

110, 120, 130, 140, 150, 160, 170, 180‧‧‧ steps

200‧‧‧Circuit Board

210‧‧‧Circuit board substrate

215‧‧‧ opening

220‧‧‧ groove

220a‧‧‧Gap

225‧‧‧first plating

230‧‧‧copper

235‧‧‧ flatten the surface of the circuit board

240‧‧‧Second plating layer

245‧‧‧ patterned photosensitive film

250‧‧‧ third plating

FIG. 1 is a flowchart of a printed circuit board manufacturing method according to an embodiment of the present disclosure.

FIG. 2A to FIG. 2G are schematic cross-sectional views of steps in a method for manufacturing a printed circuit board according to an embodiment of the present disclosure.

The following is a detailed description of the embodiments in conjunction with the drawings to better understand the aspect of the case. However, this disclosure can be implemented in many different forms, and should not be construed as being limited to the embodiments set forth in this disclosure. Rather, these embodiments are provided so that the disclosure is thorough and comprehensive, and the scope of the disclosure may be fully conveyed to those skilled in the art. In the drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. Similar numbers mean similar elements. It should be understood that although the terms first, second, third, etc. may be used in this disclosure to describe various elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another. Therefore, the first element discussed below may be referred to as the second element without departing from the teachings of the present disclosure concept. As used in this disclosure, the term "and / or" includes any and all combinations of one or more of the associated listed items. Exemplary embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

Refer to Figure 1. FIG. 1 is a flowchart of a printed circuit board manufacturing method 100 according to an embodiment of the present disclosure. The printed circuit board manufacturing method 100 is taken as an example, and it is not intended to limit the present disclosure beyond that explicitly stated in the scope of the patent application. category. Additional operations may be provided before, during, and after the printed circuit board manufacturing method 100, and some of the operations described may be replaced, eliminated, or relocated to achieve additional implementations of the method. The printed circuit board manufacturing method 100 is described below with reference to FIGS. 2A to 2G. FIG. 2A to FIG. 2G are schematic cross-sectional views illustrating steps of a method for manufacturing a circuit board 200 according to an embodiment of the present disclosure.

In step 110, referring also to FIG. 2A, the printed circuit board manufacturing method 100 provides a circuit board substrate 210 in the circuit board 200, and processes an opening 215 in the circuit board substrate 210. In some embodiments, the method of processing the opening 215 may be performed by drilling, for example, mechanical layers may be used to drill through each layer in the substrate 210 of the circuit board, that is, together with a resin layer (such as a phenol resin or (Oxygen resin) is drilled through with the copper foil layer to form a hole, and the opening 215 can also be formed by laser drilling. In some embodiments, the circuit board substrate 210 may be a Copper Clad Laminate (CCL) including glass fiber (FR4).

In step 120, referring to FIG. 2B, the printed circuit board manufacturing method 100 electroplating a first plating layer 225 on the circuit board substrate 210. The first plating layer 225 covers the surface of the circuit board substrate 210, and the thickness of the first plating layer 225 can be determined according to the actual needs of the designer. In some embodiments, the material of the first plating layer 225 may include copper (Cu), aluminum (Al), nickel (Ni), gold (Cu), or a combination thereof. In some embodiments, the first plating layer 225 may be a metal sheet formed of a conductive metal, such as a copper foil.

In step 130, referring also to FIG. 2C, the printed circuit board manufacturing method 100 presses a copper block 230 into the opening 215 of the circuit board 200, where copper The size of the block 230 is limited. Specifically, after the opening 215 is processed between the circuit board substrate 210 and the first plating layer 225 is plated, in this embodiment, a copper block matching the size of the opening 215 is selected to reduce the pressure after the copper block 230 is pressed. There may be a problem caused by a gap between the copper block 230 and the circuit board substrate 210. In some embodiments, the copper block 230 protrudes from the first plating layer 225 on the circuit board substrate 210. In this embodiment, the copper block 230 and the first plating layer 225 are electrically connected. In some embodiments, the copper block 230 may be selected from red copper (C1100) having a thermal conductivity of 391 W / mk and a thermal conductivity of 97%, which may have better thermal conductivity.

In step 140, the 2D diagram is simultaneously referred to. In this embodiment, although the size of the pressed copper block 230 matches the size of the opening 215, there may still be a slight gap. Therefore, the printed circuit board manufacturing method 100 planarizes the surface of the substrate 210 to form a substrate. Flatten the circuit board surface 235. In some embodiments, the surface of the circuit board substrate 210 can be leveled by an automatic pressure grinding machine or a grinding machine, such as the operation of mechanical equipment such as an eight-axis grinding machine, a ceramic brush grinding machine, and the like to grind the copper block. 230, thereby forming a flattened circuit board surface 235 with a flat top surface. In some embodiments, the planarization process may use sand blasting and mechanical polishing to cut a portion of the protruding copper block 230 to form a planarized circuit board surface 235. In some implementations, the first plating layer 225 is a copper plating layer. Therefore, when the surface of the circuit board substrate 210 is planarized in step 140, the ductility of the copper of the first plating layer 225 can be used to facilitate the rectification. Flatten the surface of the circuit board substrate 210, and at the same time help to eliminate the gap between the copper block 230 and the circuit board substrate 210, thereby forming a flattened circuit board surface 235.

In step 150, referring to FIG. 2E at the same time, the printed circuit board manufacturing method 100 electroplating a second plating layer 240 on the surface 235 of the planarized circuit board, wherein the thickness of the second plating layer 240 can be according to the actual needs of the designer It depends. In some embodiments, the second plating layer 240 is performed by capping plating, for example, copper capping plating to form a desired copper cap, and cover the copper cap. The planarized circuit board surface 235 is planarized. In other words, the second plating layer 240 covers the first plating layer 225 and the copper block 230. In some embodiments, the surface between the copper block 230 and the circuit board substrate 210 is electrically connected to the first plating layer 225, and the other surfaces of the copper block 230 are covered by the second plating layer 240. In some embodiments, the material of the second plating layer 240 may include copper (Cu), aluminum (Al), nickel (Ni), gold (Cu), or a combination thereof. In some embodiments, the second plating layer 240 may be a metal foil formed of a conductive metal, such as a copper foil. In some embodiments, the first plating layer 225 and the second plating layer 240 may be plating layers formed of the same conductive metal. For example, the first plating layer 225 is a copper plating layer, and the second plating layer 240 is also copper. Plating.

In step 160, referring to FIG. 2F at the same time, the printed circuit board manufacturing method 100 forms a photosensitive film, and refers to the position of the patterned photosensitive film 245 in FIG. 2F, and has not been patterned, and is formed on the second plating layer 240. Above. The photosensitive material contained in the photosensitive film refers to a material that reacts to light and undergoes intra- or inter-molecular changes after absorbing light energy, resulting in a difference in the dissolution rate of the developing solution between the exposed and unexposed areas. Therefore, in this embodiment, Medium, the photosensitive film can have good plating resistance, sensitivity and adhesion, can protect the pattern form. In some embodiments, the photosensitive film may include a photosensitive material such as a photoresist, such as a photosensitive resin film, a negative film, and the like.

In step 170, referring to FIG. 2F at the same time, the printed circuit board manufacturing method 100 performs a patterning process to form a patterned photosensitive film 245 to expose a plurality of grooves 220 of the circuit board substrate 210, wherein the grooves 220 A plurality of gaps 220a between the periphery of the copper block 230 and the circuit board substrate 210 are further included. In some embodiments, the patterned photosensitive film 245 may be formed by an image transfer process. The image transfer process may include coating, soft baking, mask alignment, exposure, post-exposure baking, development, cleaning, and drying. step.

In step 180, referring to FIG. 2G at the same time, the printed circuit board manufacturing method 100 electroplates a third plating layer 250 and fills the groove 220 on the surface of the circuit board. Specifically, the grooves 220a including the gap 220a around the copper block 230 and the circuit board substrate 210 exposed in FIG. 2F are filled with the third plating layer 250, so that the periphery of the copper block 230 is flattened. That is, the third plating layer 250 and the patterned photosensitive film 245 cover the copper block 230. In some embodiments, the third plating layer 250 is plated by pattern plating to fill the grooves 220 including the gaps 220a. In some embodiments, the top surface of the third plating layer 250 and the top surface of the patterned photosensitive film 245 form a plane. In some embodiments, the third plating layer 250 may be a metal foil formed of a conductive metal, such as a copper foil. In some embodiments, the first plating layer 225, the second plating layer 240, and the third plating layer 250 are plating layers formed of the same conductive metal, such as the first plating layer 225, the second plating layer 240, and the third plating layer. The plating layers 250 are all copper plating layers.

In some embodiments, the third plating layer 250 may be formed using a semi-additive process.

In some embodiments, the present disclosure can perform subsequent processing after step 180. For example, the outer positive film can be formed by a DES (developing, etching, and stripping) process method. The DES process method includes three parts: developing, etching, and stripping to obtain the required pattern. , And can further use the film to dissolve and rinse the dry film on the graphic.

Although this disclosure describes the disclosed printed circuit board manufacturing method as a series of steps, it should be understood that the order of the steps shown should not be construed as limiting its meaning. In addition, not all steps shown herein are necessary to implement one or more aspects or embodiments described in this disclosure. Furthermore, one or more steps of the present disclosure may be performed in one or more separate steps and / or stages.

In summary, the printed circuit board and its manufacturing method provided by this disclosure can achieve good heat dissipation effects through steps such as electroplating, pressing copper blocks, planarization process, forming photosensitive films and patterning photosensitive films, and can eliminate The gap between the circuit board and the copper block can improve the problem that the solder paste and the thermal conductive paste flow to the back of the circuit board during the circuit board manufacturing process, thereby improving the efficiency of the electronic product.

This disclosure has been disclosed as above in the form of implementation, but it is not intended to limit the content of this disclosure. Any person skilled in this art can make various changes and decorations without departing from the spirit and scope of this disclosure. Therefore, this disclosure The scope of protection shall be determined by the scope of the attached patent application.

Claims (9)

A printed circuit board manufacturing method includes: providing a circuit board substrate, processing an opening on the circuit board substrate; electroplating a first plating layer on the circuit board substrate; and pressing a copper block on the circuit board substrate. In the opening; flattening the surface of the circuit board substrate to form a flattened circuit board surface; electroplating a second electroplating layer over the planarized circuit board surface; forming a photosensitive film on the second electroplating layer And patterning the photosensitive film to expose a plurality of grooves of the circuit board substrate, wherein the grooves include a plurality of gaps between the periphery of the copper block and the circuit board substrate. The manufacturing method according to claim 1, further comprising: plating a third plating layer, and filling the grooves of the circuit board substrate. The manufacturing method according to claim 2, wherein the first plating layer, the second plating layer, and the third plating layer are copper plating layers. The manufacturing method according to claim 1, further comprising: electrically connecting the first plating layer and the copper block. A printed circuit board includes: a circuit board substrate having an opening; a first plating layer formed on the circuit board substrate; A copper block is disposed in the opening, wherein the first plating layer and the surface of the copper block together form a flat plane; a second plating layer is formed on the first plating layer; a patterned photosensitive film Is formed on the second plating layer; and a third plating layer is formed on the second plating layer, wherein the third plating layer and the surface of the patterned photosensitive film together form a flat plane. The printed circuit board according to claim 5, wherein the substrate of the circuit board further includes a plurality of grooves, and the patterned photosensitive film exposes the grooves, wherein the grooves include the periphery of the copper block and the circuit board base. At multiple gaps between materials. The printed circuit board according to claim 6, wherein the third plating layer is filled in the grooves of the circuit board substrate. The printed circuit board according to claim 7, wherein the first plating layer, the second plating layer, and the third plating layer are copper plating layers. The printed circuit board according to claim 5, wherein the first plating layer is electrically connected to the copper block.