KR100688825B1 - Manufacturing Method of Printed Circuit Board Using Projection Welding Method - Google Patents

Abstract

The present invention is a coreless method that does not use a core material. Projection welding in which current paths are limited by bump and pressurization of a welded material by energizing current at different contacts at a time. It relates to a method of manufacturing a printed circuit board using the method.

A method of manufacturing a printed circuit board using the projection welding method according to the present invention includes a first step of forming a bump in a conductive material layer; A second step of applying a thermoplastic resin to the bump-formed surface of the conductive material layer; Applying a conductive material to the thermoplastic resin layer; A fourth step of welding the contacts between the bump and the conductive material layer by a projection welding method; And a fifth step of forming a circuit including a predetermined pattern.

Projection, Bump, Thermoplastic, Dry Film

Description

Method for fablicating print circuit board using method for projection welding}

1A to 1F are cross-sectional views showing the flow of a method of manufacturing a printed circuit board manufactured according to the first embodiment of the present invention.

2A to 2G are cross-sectional views illustrating a flow of a method of manufacturing a printed circuit board manufactured according to the second embodiment of the present invention.

3A to 3E are cross-sectional views showing the flow of a method of manufacturing a printed circuit board manufactured according to the third embodiment of the prior art.

4A to 4G are cross-sectional views illustrating a flow of a method of manufacturing a printed circuit board using the projection method according to the first embodiment of the present invention.

5A to 5G are cross-sectional views illustrating a flow of a method of manufacturing a printed circuit board using the projection method according to the second embodiment of the present invention.

6A to 6G are cross-sectional views illustrating a flow of a method of manufacturing a printed circuit board using the projection method according to the third embodiment of the present invention.

7A to 7G are cross-sectional views illustrating a flow of a method of manufacturing a printed circuit board using the projection method according to the fourth embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

100 disc 304: pressure member

101: insulation layer 305: backing plate

102a, 102b: Copper foil 306: Copper foil

103a, 103b: copper plating layer 307: protective film

104a, 104b: Dry Film 308: Through Hole

201: insulating layer 401: lower copper layer

202a, 202b: copper foil 402: dry film

203a, 203b: copper plating layer 403: copper plating layer

204: conductive paste 404: bump

205a, 205b: dry film 405: thermoplastic resin

301: copper foil 406: upper copper layer

302: bump A, B: through hole

303: Synthetic Resin Sheet

The present invention relates to a method for manufacturing a printed circuit board, and more particularly, to a bumpless and pressurized material of a to-be-welded material by applying a current to a different contact at a time as a coreless method without using a core material. The present invention relates to a method for manufacturing a printed circuit board using a projection welding method in which current paths are limited.

Recently, in a double-sided printed circuit board or a multilayered printed circuit board, electrical connection between wiring layers such as a double-sided conductive pattern is performed in the following manner. First, in the case of a double-sided printed circuit board, drilling (or drilling) processing is performed at a predetermined position of the double-sided copper foil substrate, and after chemical plating treatment on the entire surface including the inner wall surface of the hole formed after drilling (or drilling), electroplating treatment The electrical connection between the wiring layers, which makes the metal layer on the inner wall of the furnace thick and thickens the conduction reliability, is performed.

In the case of a multilayer printed circuit board, the copper foils on both sides of the substrate are patterned, and the copper foils are laminated and arranged on the pattern using an insulating layer, and then integrated by a heating and pressing method. It is manufactured by increasing the number of laminated printed circuit boards. In the above-described method of manufacturing a printed circuit board, the electrical connection between the wiring layers is performed by a plating method. In another method, the conductive paste is drilled (or drilled) at a predetermined position on the double-sided copper foil substrate, and a conductive paste is inserted into the hole. After making it flow in and hardening resin powder of the electrically conductive paste which flowed in the hole, the method of electrically connecting between wiring layers is performed.

1A to 1F are cross-sectional views showing the flow of a method of manufacturing a printed circuit board manufactured according to the first embodiment of the present invention.

As shown in FIG. 1A, an original plate 100, which is a copper-clad laminate including copper foils 102a and 102b, is prepared on both surfaces of the insulating layer 101 and the insulating layer 101, and as shown in FIG. 1B, using a laser. Conductive holes A are formed on both sides of the disc 100 for electrical conduction.

Thereafter, as shown in FIG. 1C, the surface of the disc 100 and the inside of the through hole A are copper plated 103a and 103b. Since the electrolytic copper plating that requires electricity cannot be performed on the insulating layer 101, electroless copper plating is usually performed first, followed by electrolytic copper plating.

Then, as shown in FIG. 1D, the dry films 104a and 104b are coated and subjected to exposure and development processes. Thereafter, as shown in FIG. 1E, predetermined circuit patterns 103a and 103b are formed by using the dry films 104a and 104b cured through the exposure and development processes as etching resists.

Finally, as illustrated in FIG. 1F, when the dry films 104a and 104b are peeled off, an inner layer including the predetermined circuit patterns 103a and 103b is formed.

Next, FIGS. 2A to 2G are cross-sectional views illustrating a flow of a method of manufacturing a printed circuit board manufactured according to the second embodiment of the present invention.

As shown in FIG. 2A, an original plate 200, which is a copper clad laminate including copper foils 202a and 202b, is prepared on both surfaces of the insulating layer 201 and the insulating layer 201, and as shown in FIG. 2B, using a laser. The through hole B is formed in the insulating layer 201 and the double-sided copper foils 202a and 202b of the master plate 200.

Thereafter, as shown in FIG. 2C, the surface of the disc 200 and the inside of the through hole B are copper plated 203a and 203b. Since the electrolytic copper plating that requires electricity cannot be performed on the insulating layer 201, electroless copper plating is usually performed first, followed by electrolytic copper plating.

Also, as shown in FIG. 2D, the conductive hole B is filled with the conductive paste 204 and then polished with a buffer or the like. Then, as shown in FIG. 2E, the dry films 205a and 205b are applied, and the exposure and development processes are performed.

Thereafter, as shown in FIG. 2F, predetermined circuit patterns 203a and 203b are formed by using the dry films 205a and 205b cured through the exposure and development processes as etching resists, and finally, as shown in FIG. 2G. When the dry films 205a and 205b are peeled off, an inner layer including the predetermined circuit patterns 203a and 203b is formed.

In this first embodiment, since the via hole A for electrical connection between the wiring layers is formed on the substrate, and the plating process including the inner wall of the formed via hole A is required, the manufacturing process of the printed circuit board is not simple. There was a complicated problem. On the other hand, also in the second embodiment, as in the first embodiment, the via hole B formation process is required, and in addition, it is difficult to fill the uniform conductive paste 204 inside the via hole B, and in electrical connection, There was a problem with its reliability.

In addition, since the first and second embodiments require the formation of via holes A and B, there is a problem that the cost of the printed circuit board cannot be reduced.

In addition, in the first and second embodiments, since the via holes A and B are formed in the connection between the wiring layers in the printed circuit board, wiring cannot be formed and arranged in the via hole A and B regions. In addition, there is a problem that the improvement of the wiring density is restricted and the improvement of the mounting density of the electronic component is also inhibited.

3A to 3E are cross-sectional views showing the flow of the manufacturing method of the printed circuit board manufactured by the third embodiment of the prior art.

As shown in FIG. 3A, first, an electrolytic copper foil 301 used for manufacturing a printed circuit board is prepared, and a bump 302 printed with a conductive paste is laminated on the copper foil 301.

Next, as shown in FIG. 3B, the synthetic resin sheet 303, the press member 304 formed of the silicone rubber plate, and the backing plate 305 are disposed and mounted on a press apparatus including a heating, pressing and cooling mechanism, and do not pressurize. Heated without lamination to batch.

Then, as shown in FIG. 3C, when the temperature rises to 250 ° C., a laminate obtained by inserting the synthetic resin sheet 303 can be obtained. Then, as in 3D, the electrolytic copper foil 306 and the protective film 307 are obtained. Lay each one.

Finally, as shown in FIG. 3E, when heated to 270 ° C. and then pressurized to cool, the protective film 307 may fall and a double-sided printed circuit board having a through hole 308 may be obtained.

Here, in the third embodiment of the prior art, the process of drilling and plating filling for forming the through hole is omitted, but there is a problem in that the joint reliability is lowered due to the thermal gradient by the high temperature compression method when connecting the bumps.

The technical problem of the present invention for solving the above problems is to provide a method of manufacturing a printed circuit board using a projection welding method which has a simplified process and high bonding reliability between bumps and copper foil.

In order to solve the above technical problem, a method of manufacturing a printed circuit board according to the present invention comprises a first step of forming a bump on the conductive material layer; A second step of applying a thermoplastic resin to the bump-formed surface of the conductive material layer; Applying a conductive material to the thermoplastic resin layer; A fourth step of welding the contacts between the bump and the conductive material layer by a projection welding method; And a fifth step of forming a circuit including a predetermined pattern.

Hereinafter, a manufacturing method of a printed circuit board using the projection welding method according to the present invention will be described in detail with reference to the drawings.

4A to 4G are cross-sectional views illustrating a flow of a method of manufacturing a printed circuit board using the projection welding method according to the first embodiment of the present invention.

As in FIG. 4A, the dry film 402 is laminated on the thin copper coil 401. Here, it is preferable that the dry film 402 apply | coats the dry film for bump formation.

Next, as illustrated in FIG. 4B, the coated dry film 402 is subjected to an exposure and development process using an artwork film or a glass mask including a predetermined pattern. The applied dry film 402 is used as a plating resist by an additive method, and a portion cured by an exposure process forms a predetermined pattern, and an uncured portion is removed by a development process.

Then, as shown in FIG. 4C, electrolytic copper plating 403 is performed to grow the thin goofy foil 401 thickly to form a bump 404 according to the pattern of the dry film 402, and to peel off the dry film 402. do. At this time, the growth thickness of the copper foil 401 is grown in consideration of the growth rate of the bump 404 so that the copper foil 401 to the desired thickness. Here, in the method of forming the electrolytic copper plating layer 403, the original plate 400 is eroded into the copper plating working cylinder, and then the electrolytic copper plating 403 is performed using a DC rectifier. The electrolytic copper plating 403 is preferably used to calculate the area to be plated to deposit a suitable current in the DC rectifier.

In the electrolytic copper plating 403 process, the physical properties of the copper plating layer 403 are superior to the electroless copper plating layer, and there is an advantage in that a thick copper plating layer 403 is easily formed.

The copper plating lead wire for forming the electrolytic copper plating layer 403 may use a copper plating lead wire formed separately, but in a preferred embodiment of the present invention, the copper plating lead wire for forming the electrolytic copper plating layer uses a copper foil 401. It is preferable.

Thereafter, as shown in FIG. 4D, the thermoplastic resin 405 is coated and adhered. Here, the thermoplastic resin 405 is preferably polyethylene, nylon, polyacetal resin, vinyl chloride resin, polystyrene, ABS resin, acrylic resin and the like.

Then, as in FIG. 4E, unnecessary thermoplastic resin 405 is polished and copper 406 is applied. It is preferable to use a buffer or the like for polishing the unnecessary thermoplastic resin 405 here.

Then, as shown in Fig. 4F, the project welding is performed by flowing electricity to the copper layers 403 and 406 on both sides. Here, when electricity is supplied to the copper layers 403 and 406 on both sides, the bump contact is welded while melting, so that the joining reliability is improved. Projection welding is limited in the current path by the bump 404 and the pressure of the welded material, the resistance heat is generated in the limited current path of the bump 404 and its relative welded material is welded by melting the contact.

Finally, as in FIG. 4G, circuit patterns 403 and 406 are formed on both sides. Here, the circuit patterns 403 and 406 on both sides are formed through a general circuit forming step.

5A to 5G are cross-sectional views illustrating a flow of a method of manufacturing a printed circuit board using the projection welding method according to the second embodiment of the present invention.

As shown in FIG. 5A, original plates coated with dry films 502 and 503 on both surfaces of the copper layer 501 and the copper layer 501 are prepared. It is preferable to apply the bump forming dry film 502 to the upper surface of the copper layer 501 and to apply the dry film 503 for exposure and plating to the lower surface of the copper layer. In addition, a thicker copper layer 501 is used than the copper layer 401 used in the first embodiment. That is, since the copper layer 501 is not electroplated, what is necessary is just to prepare the plating layer of desired plating thickness in advance.

Next, as shown in FIG. 5B, the dry films 502 and 503 on both surfaces of the copper layer 501 are exposed and developed. Here, the part hardened | cured by the exposure process forms a predetermined pattern, and the part which is not hardened is removed by the image development process.

5C, electrolytic plating 504 is performed to form bumps 504 according to the patterns of the dry films 502 and 503, and the dry films 502 and 503 are removed. Here, in the method of forming the electrolytic copper plating layer 504, the electroplated copper plating 504 is performed by using a direct current rectifier after eroding the original plate 500 in the copper plating 504 working cylinder. The electrolytic copper plating 504 is preferably used to calculate the area to be plated to deposit a suitable current in the DC rectifier.

Thereafter, as shown in FIG. 5D, the thermoplastic resin 505 is coated and adhered. Here, the thermoplastic resin 505 is preferably polyethylene, nylon, polyacetal resin, vinyl chloride resin, polystyrene, ABS resin, acrylic resin and the like.

Then, as in FIG. 5E, the unnecessary thermoplastic resin 505 is polished and the copper layer 506 is applied. It is preferable to use a buffer or the like for polishing the unnecessary thermoplastic resin 505 here.

Then, as in FIG. 5F, electricity is supplied to the copper layers 501 and 506 on both sides to perform project welding. In this case, when electricity is supplied to the copper layers 501 and 506 on both sides, the bump 504 contacts are welded while melting, thereby improving the joining reliability. In addition, the projection welding is limited in the current path by the bump 504 and the pressure of the material to be welded, the heat of resistance is generated in the limited current path of the bump 504 and its relative to-be-welded material to be welded by melting the contact portion.

Finally, as in FIG. 5G, circuit patterns 501 and 506 are formed on both sides.

Here, the circuit patterns 501 and 506 on both sides are formed through a general circuit forming step.

6A to 6G are cross-sectional views illustrating a flow of a method of manufacturing a printed circuit board using the projection welding method according to the third embodiment of the present invention.

First, as shown in FIG. 6A, a dry film 602 is coated on a thick copper layer 601. Here, it is preferable to prepare a thick copper layer 601 to form the bump 603. At this time, since the thickness of the copper layer 601 is opposite to the surface of the bump 603 side, the thickness of the copper layer 601 is thicker in advance so as to be the desired thickness of the copper layer 601 and the bump 603 after etching in consideration of the etching rate. Prepare. Moreover, it is preferable that the dry film 602 apply | coats the dry film 602 for bump formation.

Next, as shown in FIG. 6B, an exposure and development process is performed on the dry film 602 of the upper surface of the copper layer 601. Here, the cured portion of the dry film 602 by the exposure process forms a predetermined pattern, and the uncured portion of the dry film 602 is removed by the developing process. As the developer, an aqueous solution of sodium carbonate (Na ₂ CO ₃ ) or potassium carbonate (K ₂ CO ₃ ) is used.

6C, the etching process and the dry film 602 are peeled off to form bumps. Here, the dry film 602 in which the predetermined pattern is formed is used as an etching resist, and the remaining portions are etched by a wet etching method. Moreover, it is more preferable to etch by adjusting the etching time at the time of wet etching suitably.

Thereafter, as shown in FIG. 6D, the thermoplastic resin 604 is coated and adhered. Here, the thermoplastic resin 604 is preferably polyethylene, nylon, polyacetal resin, vinyl chloride resin, polystyrene, ABS resin, acrylic resin and the like.

Then, as in FIG. 6E, the unnecessary thermoplastic resin 604 is polished and the copper layer 605 is applied. It is preferable to use a buffer or the like for polishing the unnecessary thermoplastic resin 604 here.

6F, project welding is performed by flowing electricity to the copper layers 601 and 605 on both sides. Here, when electricity is supplied to the copper layers 601 and 605 on both sides, the bump 603 contacts are melted and welded, so that the joining reliability is improved. In the projection welding, a current path is limitedly formed by the bump 603 and pressure of the welded material, and resistance heat is generated in the limited current path of the bump 603 and its relative welded material to be welded by melting the contact portion.

Finally, as in FIG. 6G, circuit patterns 601 and 605 are formed on both sides. Here, the circuit patterns 601 and 605 on both sides are formed through a general circuit forming step.

7A to 7G are cross-sectional views illustrating a flow of a method of manufacturing a printed circuit board using the projection welding method according to the fourth embodiment of the present invention.

First, as shown in FIG. 7A, dry films 702 and 703 are applied to upper and lower copper layers 701 having a relatively thin thickness as compared with the third embodiment. The reason why the relatively thin copper layer 701 is used in comparison with the copper layer 601 mentioned in the third embodiment is that only the bump 704 is etched, unlike the third embodiment, in which both surfaces are etched. Here, it is preferable that the upper dry film 702 for the double-sided circuit is coated with the bump forming dry film 702 and the lower dry film 703 is coated with the dry film 703 for exposure and etching.

Next, as shown in FIG. 7B, exposure and development processes are performed on the dry films 702 and 703 on both sides of the copper layer 701. Here, the part hardened | cured by the exposure process of the dry films 702 and 703 forms a predetermined pattern, and the part which is not hardened is etched by the image development process. Here, the developer uses sodium carbonate (Na ₂ CO ₃ ) or potassium carbonate (K ₂ CO ₃ ) aqueous solution.

As shown in FIG. 7C, the etching process and the dry films 702 and 703 are peeled off to form the bumps 704. Here, dry films 702 and 703 having a predetermined pattern are used as etching resists, and the remaining portions are etched by a wet etching method. Moreover, it is more preferable to etch by adjusting the etching time at the time of wet etching suitably.

Thereafter, as shown in FIG. 7D, the thermoplastic resin 705 is coated and adhered. Here, the thermoplastic resin 705 is preferably polyethylene, nylon, polyacetal resin, vinyl chloride resin, polystyrene, ABS resin, acrylic resin and the like.

Then, as in FIG. 7E, the unnecessary thermoplastic resin 705 is polished and the copper layer 706 is applied. It is preferable to use a buffer or the like in order to polish the unnecessary thermoplastic resin 705 here.

Then, as in FIG. 7F, electricity is supplied to the copper layers 701 and 706 on both sides to perform project welding. Here, when electricity is supplied to both surfaces of the copper layers 701 and 706, the bump 704 contact is welded while melting, thereby improving the joining reliability. In addition, in the projection welding, a current path is limitedly formed by the bump 704 and the pressurized material to be welded, and resistance heat is generated in the limited current path of the bump 704 and its relative welded material to be welded by melting the contact portion.

Finally, as in FIG. 7G, circuit patterns 701 and 706 are formed on both sides. Here, the circuit patterns 701 and 706 on both sides are formed through a general circuit forming step.

Although the present invention has been described above, this is only one embodiment, and it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. . However, it will be confirmed through the claims that such changes and modifications fall within the scope of the present invention.

As described above, according to the method of manufacturing a printed circuit board using the projection method according to the present invention, the bonding reliability is much better than that of the bump bonding reliability of the conventional high temperature compression method (general high temperature compression method ≒ 0.6 to 0.8 kgf / cm , Projection ≒ 2 kgf / cm or more).

In addition, according to the method of manufacturing a printed circuit board using the projection method according to the present invention, there is no drilling and electroless plating process for the formation of a through hole, thereby simplifying the process, thereby reducing the manufacturing cost. .

In addition, according to the method of manufacturing a printed circuit board using the projection method according to the present invention, by freely adjusting the layer thickness to make a substrate of a small thickness, it is possible to transmit signals without loss of electrical signals and to manufacture bumps with a diameter of 50 μm or less. There is an effect to enable the formation of a fine circuit.                     

In addition, according to the method of manufacturing a printed circuit board using the projection method according to the present invention, since the through hole does not exist, there is an effect of improving the degree of freedom in design and increasing the wiring density.

Claims (5)

Forming a bump in the conductive material layer; A second step of applying a thermoplastic resin to the bump-formed surface of the conductive material layer; Applying a conductive material to the thermoplastic resin layer; A fourth step of welding the bump and the conductive material by a projection welding method; And A method of manufacturing a printed circuit board using a projection welding method, comprising the step of forming a circuit including a predetermined pattern. The method of claim 1, The first step is, Step 1-1 applying a bump forming dry film to one surface of the conductive material layer; The coated bump forming dry film may include forming a bump pattern by developing an uncured portion corresponding to a bump forming part; And Electroplating the conductive material layer to form a bump by plating the inside of the etched bump pattern formed on the upper surface of the conductive material layer on which the lower surface of the conductive material layer is plated with a conductive material, and removing the dry film for bump formation A method for manufacturing a printed circuit board using a projection welding method, comprising the steps 1-3. The method of claim 1, The first step is, A first step of applying a bump dry film on one surface of the conductive material layer and a dry film for exposure and plating on the other surface; The coated bump forming dry film may include forming a bump pattern by developing an uncured portion corresponding to a bump forming part; And Manufacturing a printed circuit board using the projection welding method, characterized in that the first step of forming the bumps and removing the dry film on both sides by plating the inside of the etched bump pattern formed on the upper surface of the conductive material layer with a conductive material Way. The method of claim 1, The first step is, Step 1-1 applying a bump forming dry film to one surface of the conductive material layer; The coated bump forming dry film may further include developing the uncured portions other than the bump patterns corresponding to the bump forming portions; And Etching the remaining portions except the portion corresponding to the bump pattern to a predetermined depth with respect to the surface on which the dry film of the conductive layer is stacked to form a bump, and etching the opposite surface to a predetermined thickness, and drying the bump forming A method of manufacturing a printed circuit board using a projection welding method comprising the step 1-3 of removing the film. The method of claim 1, The first step is, A first step of applying a bump dry film on one surface of the conductive material layer and a dry film for exposure and plating on the other surface; The coated bump forming dry film may further include developing the uncured portions other than the bump patterns corresponding to the bump forming portions; And And forming a bump shape by etching the conductive material layer and removing dry films on both sides of the conductive material layer.

Images