JP2011134758A - Manufacturing method for printed board and printed board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a printed board and a printed board by which when a thick copper circuit pattern of, for example, 70 μm or more in thickness is formed, a high-density current is not used to achieve a uniformed film thickness distribution. <P>SOLUTION: A copper thin film 2 is formed on a tabular support, and a first resist is formed on the surface of the copper thin film 2, which is then plated with copper to form an inside copper circuit 5. The first resist is removed, and an insulating base material 7 is overlaid on the surface of the copper thin film 2 to cover the inside copper circuit 5. The support is then removed, and a second resist is formed on the back surface of the surface of copper thin film 2 from which the support is removed. The back surface of the copper thin film 2 is plated with copper to form an outside copper circuit 10, and the second resist is removed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a printed circuit board manufacturing method and a printed circuit board capable of suitably forming a thick copper circuit.

  Conventionally, when manufacturing a thick copper circuit board of, for example, 70 μm or more, a circuit pattern is formed by etching a copper circuit using a copper foil or a copper-clad laminate equivalent to the circuit thickness. However, the cross section of the copper circuit manufactured by such an etching method has a trapezoidal shape because the upper part of the pattern becomes narrower than the design value due to the nature of the construction method. Furthermore, if the thickness of the copper substrate is 70 μm or more, the upper part of the pattern becomes thinner than necessary, and it becomes difficult to mount components after forming the copper circuit pattern. Further, the above-described copper-clad laminate is very expensive when it is thick copper, and when the etching method is used, the consumption of copper is severe, and therefore there is a lot of wasted copper.

  The problem of the etching method described above is described in Patent Document 1. Patent Document 1 points out that the cross-sectional shape of the wiring pattern is a trapezoidal shape with a wide bottom portion on the substrate side, and describes that there is a pattern plating method to solve this (Patent Document 1). Paragraphs 0002 to 0003). An example is shown in which a thick copper plating pattern having a thickness of 70 μm is formed (paragraph 0035 of Patent Document 1).

  However, when such a thick copper circuit of 70 μm is formed, conventionally, it is formed by increasing the current density. When a thick copper circuit is formed by increasing the current density in this way, the current concentrates, which causes a variation in the film thickness distribution. Since patent document 1 aims at reducing the side etching amount of the base copper foil in the printed circuit board in which the copper wiring pattern was formed, this problem is not solved.

JP-A-6-152101

  The present invention is based on the above prior art, and for example, when forming a thick copper circuit pattern of 70 μm or more, it is possible to manufacture a printed circuit board that can have a uniform film thickness distribution without using a high current density. It is an object to provide a method and a printed circuit board.

  In order to achieve the above object, according to the first aspect of the present invention, a copper thin film is formed on a plate-like support, and a first opening corresponding to the front-side wiring pattern is formed on the surface of the copper thin film. A first resist that exposes the surface of the copper thin film is formed at one opening, and copper is plated on the surface of the copper thin film through the first opening to form an inner copper circuit composed of the front wiring pattern And removing the first resist, laminating an insulating base material on the surface of the copper thin film so as to cover the inner copper circuit, removing the support, and removing the support from the copper thin film. And forming a second resist that has a second opening corresponding to the back-side wiring pattern corresponding to at least a part of the front-side wiring pattern and exposes the back surface of the copper thin film in the second opening. And the second opening on the back surface of the copper thin film. Through with copper plating to form an outer copper circuit consisting of the back side wiring patterns, to provide a method of manufacturing a printed circuit board and removing the second resist.

The invention of claim 2 is characterized in that, in the invention of claim 1, the support is a carrier sheet made of silicon resin or rubber.
According to a third aspect of the present invention, a plate-shaped insulating base material and a pattern wiring provided on at least one surface side of the insulating base material are provided, and the pattern wiring is formed so as to protrude from the one surface. An outer copper circuit, an inner copper circuit embedded in the insulating base at a portion corresponding to the outer copper circuit, and a copper thin film sandwiched between the outer copper circuit and the inner copper circuit. There is provided a printed circuit board characterized by comprising:

In the invention of claim 4, in the invention of claim 3, a plurality of the pattern wirings are formed, and the thicknesses of the outer copper circuits or the inner copper circuits of each pattern wiring, or the same pattern wiring The outer copper circuit and the inner copper circuit are different in thickness.
According to a fifth aspect of the present invention, in the third aspect of the present invention, the pattern wiring is formed on both surfaces of the insulating base material.

  According to the first aspect of the present invention, even when a thick copper circuit pattern of, for example, 70 μm or more is formed, the thick copper circuit having this thickness is divided into two parts, an inner copper circuit and an outer copper circuit. Even if the density is not used, the circuit pattern can be formed quickly. Therefore, variations in film thickness (plating thickness) can be suppressed, and the film thickness distribution can be made uniform. In addition, since the thickness of each of the inner copper circuit and the outer copper circuit can be adjusted as appropriate, it is possible to form a circuit having a pattern thickness as desired.

According to invention of Claim 2, since the support body is formed with the silicon-type resin or the rubber | gum carrier sheet, the process of peeling a support body from a copper thin film can be performed smoothly.
According to the invention of claim 3, since the outer copper circuit and the inner copper circuit are in contact with each other, they can be combined to form a thick copper copper circuit.
According to the invention of claim 4, since the outer copper circuit or the inner copper circuit having different thicknesses is formed in the substrate, a printed circuit board having a circuit pattern having a desired copper thickness can be obtained.

  According to invention of Claim 5, what is called a double-sided board | substrate which has a thick copper circuit can be formed.

It is the schematic which shows the manufacturing method of the printed circuit board which concerns on this invention in order. It is the schematic which shows the manufacturing method of the printed circuit board which concerns on this invention in order. It is the schematic which shows the manufacturing method of the printed circuit board which concerns on this invention in order. It is the schematic which shows the manufacturing method of the printed circuit board which concerns on this invention in order. It is the schematic which shows the manufacturing method of the printed circuit board which concerns on this invention in order. It is the schematic which shows the manufacturing method of the printed circuit board which concerns on this invention in order. It is the schematic which shows the manufacturing method of the printed circuit board which concerns on this invention in order. It is the schematic which shows the manufacturing method of the printed circuit board which concerns on this invention in order. It is the schematic which shows the manufacturing method of the printed circuit board which concerns on this invention in order. It is the schematic which shows the manufacturing method of the printed circuit board which concerns on this invention in order. It is the schematic which shows the manufacturing method of the printed circuit board which concerns on this invention in order. It is the schematic of the printed circuit board which concerns on this invention. It is the schematic which shows manufacture of the laminated substrate using the printed circuit board which concerns on this invention in order. It is the schematic which shows manufacture of the laminated substrate using the printed circuit board which concerns on this invention in order. It is the schematic which shows manufacture of the laminated substrate using the printed circuit board which concerns on this invention in order. It is the schematic which shows manufacture of the laminated substrate using the printed circuit board which concerns on this invention in order. It is the schematic which shows manufacture of the laminated substrate using the printed circuit board which concerns on this invention in order.

1 to 11 are schematic views sequentially showing a method of manufacturing a printed circuit board according to the present invention.
As shown in FIG. 1, a copper thin film 2 is deposited on a plate-like support 1. As the support 1, for example, a SUS plate (SUS belt), a silicon-based resin, a rubber carrier sheet, or the like can be used. When the SUS plate is used, it is preferable to perform surface polishing or the like on the surface on which the copper thin film 2 is deposited. In this case, the copper thin film 2 is formed directly on the SUS plate. For example, the distance between the electrodes is 3 mm to 10 mm, the anode is insoluble, the cathode is a surface-polished and activated SUS belt that slides on a graphite plate (0.1 mm (t) to 0.6 mm (t)), and the electrolyte is The copper thin film 2 is manufactured by the high-speed plating apparatus which stirs in a turbulent state, specifies an electrolytic copper solution concentration and temperature at the same time, and employs a current density of 0.5 A / cm ^{2 to} 2.5 A / cm ² . When using a carrier sheet, it is preferable to use an adhesive sheet having flexibility and chemical resistance. In this case, the copper thin film 2 once formed on the SUS plate is peeled off and bonded to the carrier sheet. By using such a support 1, the thin copper thin film 2 can be used as a support for the following pattern formation. The copper thin film 2 is, for example, a 9 μm thick copper foil.

  As shown in FIG. 2, a first resist 3 serving as a resist pattern is formed on the surface of the copper thin film 2. The first resist 3 is formed at a predetermined position with a portion serving as a copper plating pattern (front wiring pattern) as a first opening 4. The thickness of the first resist 3 is preferably 1.4 times or more the thickness of the copper circuit to be formed. Then, as shown in FIG. 3, an inner copper circuit 5 having a front wiring pattern is formed in the first opening 4. The inner copper circuit 5 is activated at a predetermined current density (for example, 10 ASD to 20 ASD) after activating the surface of the copper thin film 2. More specifically, after being immersed in a 5% (wt) sulfuric acid bath at room temperature for 30 seconds, the copper concentration of copper sulfate is 85 g / L, the sulfuric acid is 60 g / L, the distance between the insoluble anode is 20 mm, the cathode lock is 100 mm / second, Electrolysis is performed at a jet discharge amount of 600 L / min (nozzle pitch 25 mm), a bath temperature of 40 ° C., and CD11 ASD for 20 minutes to form an inner copper circuit 5 that is thick copper circuit plating of 50 μm / min. Then, as shown in FIG. 4, the first resist 3 is peeled and removed. For this removal, for example, a sodium hydroxide solution is used, which is washed with water, neutralized with 5% sulfuric acid at room temperature for 30 seconds, and washed again with water. Thereby, the circuit pattern by the copper plating of the inner side copper circuit 5 is formed.

  Next, as shown in FIG. 5, a profile 6 is formed as a pretreatment for stacking (blackening treatment). In order to enhance the adhesion between the profile 6 and the inner copper circuit 5, the inner copper circuit 5 may be subjected to surface treatment in advance. Profile 6 is formed in order to suppress transmission loss. And as shown in FIG. 6, a circuit pattern is transcribe | transferred with the insulating base material 7, and this is hardened | cured by hot press. For example, two 0.2 mm (t) prepregs (52% resin amount) are used for the insulating base material 7. The hot pressing is performed, for example, at 170 ° C. with a vacuum degree of 4.0 kPa for 40 minutes. And as shown in FIG. 7, the support body 1 is peeled and removed. At this time, if the support 1 is formed of a silicon-based resin or a rubber carrier sheet, the process of peeling the support 1 from the copper thin film 2 can be performed smoothly. In the drawing, the substrate 1 is turned upside down after the support 1 is removed.

  Next, as shown in FIG. 8, the 2nd resist 8 is formed in the back surface of the side from which the support body 1 of the copper thin film 2 was removed. The second resist 8 is formed at a predetermined position with a portion serving as a copper plating pattern (back side wiring pattern) as a second opening 9. The second opening 9 is formed so that the inner copper circuit 5 is exposed at least partially. In the example of the drawing (sectional view), the inner copper circuit 5 is exposed in two second openings 9 out of the three second openings 9. The thickness of the second resist 8 is formed in the same manner as the first resist 3. Then, as shown in FIG. 9, the outer copper circuit 10 is formed in the second opening 9. The outer copper circuit 10 is formed in the same manner as the inner copper circuit 5. Then, as shown in FIG. 10, the second resist 8 is peeled and removed. Thereby, the circuit pattern by the copper plating of the outer side copper circuit 10 is formed.

  Next, the copper thin film 2 formed under the resist pattern of the removed second resist 8 is removed by flash etching. In this case, for example, an SPS (sodium persulfate) aqueous solution or the like is used as the etching solution. Then, the profile 6 is formed on the side surface of the copper thin film 2 and the surface of the outer copper circuit 10. The formation of the profile 6 is the same as the formation of the profile 6 of the inner copper circuit 5.

  Thus, the printed board 11 according to the present invention is manufactured. Thereby, for example, when a thick copper circuit pattern of 70 μm or more is formed, the thick copper circuit having this thickness is formed as the pattern wiring 16 divided into the inner copper circuit 5 and the outer copper circuit 10. Even if the density is not used, the circuit pattern can be formed quickly. Therefore, variations in film thickness (plating thickness) can be suppressed, and the film thickness distribution can be made uniform. The manufacturing method according to the present invention is a method for manufacturing a printed circuit board by a so-called semi-additive method, and the copper thin film 2 corresponds to the seed layer.

  When the printed circuit board manufacturing method according to the present invention is used, a printed circuit board as shown in FIG. 12 can be manufactured. As shown in the figure, when there are a plurality of pattern wirings 16 made of the inner copper circuit 5, the outer copper circuit 10, and the copper thin film 2 sandwiched between them, the circuit thickness of each pattern wiring 16, that is, the individual pattern The thicknesses of the outer copper circuits 10 of the wiring 16 or the adjacent inner copper circuits 5 or the thicknesses of the outer copper circuit 10 and the inner copper circuit 5 in the same pattern wiring 16 can be changed. This makes it possible to form a circuit having a pattern thickness as desired. It is also possible to form the outer copper circuit 10, the inner copper circuit 5, and the copper thin film 2 on both surfaces via the insulating base material 7. As described above, the printed circuit board according to the present invention can appropriately set the circuit thickness and the circuit pattern according to the usage mode.

13 to 17 are schematic views sequentially showing the production of a multilayer substrate using the printed circuit board according to the present invention.
As shown in FIG. 13, the first layer substrate 11a, the second layer substrate 11b, the third layer substrate 11c, the fourth layer substrate 11d, and the fifth layer substrate 11e are stacked from the upper side of the drawing. The first layer substrate 11a and the fifth layer substrate 11e are substrates located outside the laminated substrate, and are so-called outer layer substrates. These substrates 11 a and 11 e are formed so that only the inner copper circuit 5 faces outward and is covered with the copper thin film 2. On the other hand, among the second layer substrate 11b, the third layer substrate 11c, and the fourth layer substrate 11d as the inner layer substrate, the substrates 11b and 11d are formed with a thick copper circuit having the upper copper circuit 10, and the substrate 11c It consists of a prepreg that has been transferred. In this state, as shown in FIG. 14, through holes are drilled. This drilling is performed by a drill, for example. The through hole 12 thus formed is subjected to desmear treatment, that is, treatment for the purpose of removing the smear generated in the through hole 12 and roughening the resin in order to increase the adhesion strength with the plating. A plating 13 made of chemical copper plating is formed.

  Next, as shown in FIG. 15, a resist 15 is formed on the outer side of the first layer substrate 11a and the fifth layer substrate 11e which are the outer layer substrates. And as shown in FIG. 16, the copper circuit 14 which is a copper plating pattern is formed. Then, as shown in FIG. 17, the resist 15 is removed, and the copper thin film 2 is removed by flash etching. Thereby, a laminated substrate in which the circuit pattern of the first layer substrate 11a and the circuit pattern of the fifth layer substrate 11e are connected via the plating 13 of the through hole 12 can be obtained. The resist 15 and the copper circuit 14 are formed in the same manner as the first and second resists 3 and 8, the inner copper circuit 5 and the outer copper circuit 10 described above.

DESCRIPTION OF SYMBOLS 1 Support body 2 Copper thin film 3 1st resist 4 1st opening part 5 Inner copper circuit 6 Profile 7 Insulation base material 8 Second resist 9 2nd opening part 10 Outer copper circuit 11 Board | substrate 12 Through-hole 13 Plating 14 Copper circuit 15 Resist 16 Pattern wiring

Claims (5)

A copper thin film is formed on a plate-like support,
Forming a first resist on the surface of the copper thin film having a first opening corresponding to the front-side wiring pattern and exposing the surface of the copper thin film in the first opening;
Copper plating is performed on the surface of the copper thin film through the first opening to form an inner copper circuit composed of the front wiring pattern,
Removing the first resist;
Laminating an insulating base material on the surface of the copper thin film so as to cover the inner copper circuit,
Removing the support,
The back surface of the copper thin film from which the support is removed has a second opening corresponding to the back side wiring pattern corresponding to at least a part of the front side wiring pattern, and the copper thin film is formed at the second opening. Forming a second resist that exposes the back surface of
Copper plating is performed on the back surface of the copper thin film through the second opening, and an outer copper circuit composed of the backside wiring pattern is formed.
A method of manufacturing a printed circuit board, wherein the second resist is removed.   The method for manufacturing a printed circuit board according to claim 1, wherein the support is a carrier sheet made of silicon resin or rubber. A plate-like insulating substrate;
Pattern wiring provided on at least one surface side of the insulating base material,
The pattern wiring is
An outer copper circuit formed protruding from the one surface;
An inner copper circuit embedded in the insulating substrate at a portion corresponding to the outer copper circuit;
A printed circuit board comprising: a copper thin film sandwiched between the outer copper circuit and the inner copper circuit. A plurality of the pattern wirings are formed,
The thicknesses of the outer copper circuits or the inner copper circuits of individual pattern wirings or the thicknesses of the outer copper circuit and the inner copper circuit in the same pattern wiring are different. 3. The printed circuit board according to 3.   The printed circuit board according to claim 3, wherein the pattern wiring is formed on both surfaces of the insulating base material.

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