JP2018018934A - Printed wiring board and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring board which can be manufactured more simply than in the conventional art, and a manufacturing method of the same.SOLUTION: A printed wiring board 10 of the present invention comprises: a base substrate part 21; a first insulation resin layer 23 laminated on a first surface 21F of the base substrate part 21; a first conductor layer 24 laminated on the first insulation resin layer 23; a second insulation resin layer 33 laminated on a second surface 21S of the base substrate part 21; and a second conductor layer 34 laminated on the second insulation resin layer 33. The first insulation resin layer 23 is composed of a resin material more excellent in high frequency properties than the second insulation resin layer 33. The printed wiring board 10 further comprises a high-frequency substrate part 27 including a conductor layer 16 arranged on the outermost side of the base substrate part 21 on the first surface 21F side, the first insulation resin layer 23, and the first conductor layer 24.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a printed wiring board having an insulating resin layer excellent in high frequency characteristics and a method for manufacturing the same.

  Conventionally, as this type of printed wiring board, one in which a part of the insulating layer is made of a low dielectric constant resin material is known (for example, see Patent Document 1). In such a printed wiring board, a high-frequency substrate having an insulating resin layer having a dielectric constant lower than that of the insulating resin layer of the base substrate is bonded onto a base substrate in which conductor layers and insulating resin layers are alternately laminated. It was manufactured with.

JP 2006-40797 A (paragraphs [0012] and [0029], FIG. 5)

  However, in the conventional method for manufacturing a printed wiring board described above, it is necessary to prepare a high-frequency substrate separately from the base substrate.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a printed wiring board that can be manufactured more easily than before and a manufacturing method thereof.

  The printed wiring board of the present invention made to achieve the above object includes a base substrate portion in which conductor layers and insulating resin layers are alternately laminated, and a surface on one side of the front and back sides of the base substrate portion. A first insulating resin layer stacked on one surface, a first conductor layer stacked on the first insulating resin layer, and a second surface that is the other surface on the other side of the base substrate portion A second insulating resin layer, and a second conductor layer laminated on the second insulating resin layer, wherein the first insulating resin layer has better high frequency characteristics than the second insulating resin layer. A high-frequency substrate made of a resin material and including the conductor layer disposed on the outermost side on the first surface side of the base substrate portion, the first insulating resin layer, and the first conductor layer It further has a part.

  Further, the printed wiring board manufacturing method of the present invention made to achieve the above object includes forming a base substrate portion in which conductor layers and insulating resin layers are alternately stacked, and forming the base substrate portion. Laminating a first insulating resin layer on a first surface which is one surface of the front and back sides, forming a first conductor layer on the first insulating resin layer, and the other of the front and back sides of the base substrate portion A method for producing a printed wiring board, comprising: laminating a second insulating resin layer on a second surface that is a side surface; and forming a second conductor layer on the second insulating resin layer. The first insulating resin layer is laminated in the same process as the second insulating resin layer, and an insulating resin layer having higher frequency characteristics than the second insulating resin layer is used as the first insulating resin layer. Before the outermost substrate substrate portion is disposed on the first surface side. Forming a conductive layer, said first insulating resin layer, wherein a first conductor layer, a high-frequency substrate portion comprising.

Cross section of printed wiring board Sectional view showing manufacturing process of printed wiring board Sectional view showing manufacturing process of printed wiring board Sectional view showing manufacturing process of printed wiring board Sectional view showing manufacturing process of printed wiring board Sectional view showing manufacturing process of printed wiring board Sectional view showing manufacturing process of printed wiring board Sectional view showing manufacturing process of printed wiring board Sectional view showing manufacturing process of printed wiring board Sectional view showing manufacturing process of printed wiring board Sectional view showing manufacturing process of printed wiring board Sectional view showing manufacturing process of printed wiring board Sectional view showing manufacturing process of printed wiring board Sectional view showing manufacturing process of printed wiring board Sectional view showing manufacturing process of printed wiring board

  Hereinafter, the present embodiment will be described with reference to FIGS. As shown in FIG. 1, the printed wiring board 10 of the present embodiment includes a first insulating resin layer 23 and a first insulating layer 23 on the first surface 21F of the base substrate portion 21 having a first surface 21F and a second surface 21S on the front and back. One conductor layer 24 is laminated, and the second insulating resin layer 33 and the second conductor layer 34 are laminated on the second surface 21S. In the printed wiring board 10, there is one conductor layer (that is, the first conductor layer 24) laminated on the first surface 21F side of the base substrate portion 21, and the conductor layer (on the second surface 21S side) ( That is, the second conductor layer 34) is also one. That is, in the printed wiring board 10, the number of conductor layers laminated on the front side and the back side of the base substrate portion 21 is the same.

  The base substrate portion 21 is formed by laminating an interlayer insulating resin layer 15 and a conductor layer 16 on the front side and the back side of the core substrate 11. The core substrate 11 is formed by laminating a conductor layer 12 on the front side and the back side of the insulating base material 11K. The conductor layer 12 on the front side and the conductor layer 12 on the back side are connected by a via conductor 13 that penetrates the insulating base material 11K. The insulating base material 11K is composed of a prepreg in which a core material such as glass fiber is impregnated with a resin containing an inorganic filler.

  A plurality of interlayer insulating resin layers 15 and conductor layers 16 are provided on each of the front side and the back side of the core substrate 11. The conductor layers 16 sandwiching the interlayer insulating resin layer 15 in the thickness direction of the base substrate portion 21 are connected by via conductors 17 penetrating the interlayer insulating resin layer 15. The conductor layer 16 closest to the core substrate 11 is connected to the conductor layer 12 of the core substrate 11 by a via conductor 17 that penetrates the interlayer insulating resin layer 15 on the core substrate 11. The interlayer insulating resin layer 15 may be composed of a prepreg similar to that of the insulating base material 11K, or may be composed of a resin film that does not include a core and contains an inorganic filler. In the present embodiment, the insulating substrate 11K and the interlayer insulating resin layer 15 correspond to the “insulating resin layer” of the present invention.

  The first insulating resin layer 23 is formed on the first surface 21 </ b> F of the base substrate portion 21, and the first conductor layer 24 is formed on the first insulating resin layer 23. The first conductor layer 24 is connected to the conductor layer 16 exposed on the first surface 21 </ b> F of the base substrate portion 21 by a via conductor 25 that penetrates the first insulating resin layer 23.

  The second insulating resin layer 33 is formed on the second surface 21 </ b> S of the base substrate portion 21, and the second conductor layer 34 is formed on the second insulating resin layer 33. The second conductor layer 34 is connected to the conductor layer 16 exposed on the second surface 21 </ b> S of the base substrate portion 21 by a via conductor 35 that penetrates the second insulating resin layer 33.

  The thickness of the first insulating resin layer 23 is larger than the thickness of the second insulating resin layer 33. The thickness of the second insulating resin layer 33 is substantially the same as the thickness of the interlayer insulating resin layer 15 of the base substrate portion 21. In the example of the present embodiment, the thickness of the first insulating resin layer 23 is 100 to 200 μm, and the thickness of the second insulating resin layer 33 and the interlayer insulating resin layer 15 is 40 to 100 μm. Each thickness of the 1st conductor layer 24, the 2nd conductor layer 34, and the conductor layer 16 of the base substrate part 21 is 15-35 micrometers. In addition, the thickness of the insulating base material 11K of the core board | substrate 11 is 40-600 micrometers, Preferably, it is 40-100 micrometers.

  The first insulating resin layer 23 is made of a material having higher frequency characteristics than the second insulating resin layer 33, and the dielectric tangent of the first insulating resin layer 23 is smaller than the dielectric tangent of the second insulating resin layer 33. Yes. Specifically, the dielectric tangent of the first insulating resin layer 23 is 0.001 to 0.005, and the dielectric tangent of the second insulating resin layer 33 is, for example, 0.012. In addition, as a material which comprises the 1st insulating resin layer 23, low dielectric constant resin materials, such as a liquid crystal polymer and PTFE, are mentioned. The second insulating resin layer 33 is made of the same material as the interlayer insulating resin layer 15 of the base substrate portion 21. The relative dielectric constant of the first insulating resin layer 23 is 3.0 to 3.5, and the relative dielectric constant of the second insulating resin layer 33 is 4.1, for example.

  As shown in FIG. 1, the printed wiring board 10 has a high-frequency substrate portion 27 having a high-frequency wiring pattern on the first surface 21 </ b> F side of the base substrate portion 21. The high-frequency substrate unit 27 includes a conductor layer 16A (hereinafter referred to as “outermost conductor layer 16A”) disposed on the outermost side of the base substrate unit 21 on the first surface 21F side, a first insulating resin layer 23, and the like. And the first conductor layer 24. In the high-frequency substrate unit 27, the outermost conductor layer 16A and the first conductor layer 24 form a microstrip line 26. The outermost conductor layer 16 </ b> A constitutes the ground layer of the microstrip line 26, and the first conductor layer 24 constitutes the wiring pattern of the microstrip line 26.

  The printed wiring board 10 has a solder resist layer 37 only on the second surface 11S side of the base substrate portion 21. The solder resist layer 37 is laminated on the second conductor layer 34. An opening 37 </ b> A is formed in the solder resist layer 37. A pad 38 is formed by the second conductor layer 34 disposed inside the opening 37A.

The wiring board 10 of this embodiment is manufactured as follows.
(1) As shown to FIG. 2 (A), the copper clad laminated board 11Z by which the copper foil 11C is laminated on the both surfaces of the front and back of the insulating base material 11K is prepared.

  (2) As shown in FIG. 2 (B), for example, CO2 laser is irradiated from one side of the front and back of the copper-clad laminate 11Z to drill the tapered hole 13A. The taper hole 13A is a non-through hole whose bottom is the copper foil 11C on the other side of the front and back sides of the copper-clad laminate 11Z.

  (3) As shown in FIG. 2C, an electroless plating process is performed, and an electroless plating film 41 is formed on the copper foil 11C and the inner surface of the tapered hole 13A.

  (4) As shown in FIG. 3A, a plating resist 42 having a predetermined pattern is formed on the electroless plating film 41.

  (5) The electrolytic plating process is performed, and as shown in FIG. 3B, the electroplating is filled in the tapered hole 13A to form the via conductor 13, and the electroless plating film 41 on the copper foil 11C. An electrolytic plating film 43 is formed on the portion exposed from the plating resist 42.

  (6) The plating resist 42 is peeled off and the electroless plating film 41 and the copper foil 11C below the plating resist 42 are removed. As shown in FIG. The conductor layer 12 is formed on both the front and back surfaces of the insulating base material 11K by the electrolytic plating film 41 and the copper foil 11C. The front-side conductor layer 12 and the back-side conductor layer 12 are connected by a via conductor 13. Thereby, the core substrate 11 is obtained.

  (7) As shown in FIG. 4 (A), a prepreg is laminated as the interlayer insulating resin layer 15 on the conductor layer 12 of the core substrate 11 and a copper foil 44 is laminated, followed by heat pressing. At that time, the space between the conductor layers 12 is filled with the prepreg.

  (8) As shown in FIG. 4B, the interlayer insulating resin layer 15 is irradiated with laser from both the front and back sides of the core substrate 11 to form via holes 17A.

  (9) An electroless plating process is performed, and an electroless plating film 45 is formed on the interlayer insulating resin layer 15 and on the inner surface of the via hole 17A (see FIG. 5A).

  (10) As shown in FIG. 5B, a predetermined pattern of plating resist 46 is formed on the electroless plating film 45.

  (11) An electrolytic plating process is performed, and as shown in FIG. 6A, electrolytic plating is filled in the via hole 17A to form the via conductor 17, and the electroless plating film 45 is exposed from the plating resist 46. An electrolytic plating film 47 is formed on the part.

  (12) As shown in FIG. 6B, the plating resist 46 is peeled off, the electroless plating film 45 and the copper foil 44 below the plating resist 46 are removed, and the remaining electrolytic plating film 47, no The conductor layer 16 is formed on the interlayer insulating resin layer 15 by the electrolytic plating film 45 and the copper foil 44. The conductor layer 12 and the conductor layer 16 are connected by the via conductor 17.

  In addition, as the interlayer insulation resin layer 15, you may use the resin film which does not contain a core material and contains an inorganic filler instead of a prepreg. In that case, the conductor layer 16 can be directly formed on the surface of the resin film by the semi-additive method without laminating the copper foil 44.

  (13) The same processing as (7) to (12) described above is repeated, and as shown in FIG. 7, a plurality of interlayer insulating resin layers 15 and a plurality of conductor layers 16 are formed on both sides of the front and back of the core substrate 11. Alternatingly stacked. Thereby, the base substrate part 21 in the printed wiring board 10 is formed. The conductor layers 16, 16 sandwiching the interlayer insulating resin layer 15 are connected by via conductors 17 that penetrate the interlayer insulating resin layer 15.

  (14) As shown in FIG. 8, a sheet of low dielectric constant material as the first insulating resin layer 23 and the copper foil 50 are sequentially stacked on the first surface 21 </ b> F side of the base substrate portion 21, and the base A prepreg as the second insulating resin layer 33 and the copper foil 50 are sequentially stacked on the second surface 21S side of the substrate unit 21. The horizontal positions of the base substrate portion 21, the first insulating resin layer 23, the second insulating resin layer 33, and the copper foil 50 are as follows: the base substrate portion 21, the first insulating resin layer 23, the second insulating resin layer 33, and It is determined with reference to an alignment mark formed in advance on the copper foil 50.

  (15) Hot pressing is performed, and the first insulating resin layer 23 and the copper foil 50 are sequentially laminated on the first surface 21F of the base substrate portion 21, and on the second surface 21S of the base substrate portion 21. The second insulating resinous layer 33 and the copper foil 50 are laminated in order (see FIG. 9). At this time, the space between the conductor layers 16 and 16 exposed on the first surface 21F of the base substrate portion 21 is filled with the low dielectric constant material constituting the first insulating resin layer 23, and the base substrate portion 21 A space between the conductor layers 16 exposed on the second surface 21 </ b> S is filled with a prepreg constituting the second insulating resin layer 33.

  (16) As shown in FIG. 10, a laser is irradiated from the first surface 21F side of the base substrate portion 21 to form a via hole 25A penetrating the first insulating resin layer 23 and the copper foil 50, and the base substrate Laser is irradiated from the second surface 21 </ b> S side of the portion 21, and a via hole 35 </ b> A that penetrates the second insulating resin layer 33 and the copper foil 50 is formed.

  (17) An electroless plating process is performed, and as shown in FIG. 11, an electroless plating film 51 is formed on the copper foil 50 and the inner surface of the via hole 25A on the first surface 21F side of the base substrate portion 21. At the same time, an electroless plating film 51 is formed on the copper foil 50 and the inner surface of the via hole 35A on the second surface 21S side of the base substrate portion 21.

  (18) As shown in FIG. 12, a predetermined pattern of plating resist 52 is formed on the electroless plating film 51.

  (19) An electrolytic plating process is performed, and as shown in FIG. 13, on the first surface 21F side of the base substrate portion 21, the electroplating is filled in the via hole 25A to form the via conductor 25, and the electroless plating film 51, an electrolytic plating film 53 is formed on a portion exposed from the plating resist 52, and on the second surface 21S side of the base substrate portion 21, electrolytic plating is filled in the via hole 35A to form a via conductor 35. Then, an electrolytic plating film 53 is formed on the portion of the electroless plating film 51 exposed from the plating resist 52.

  (20) The plating resist 52 is peeled off, and the electroless plating film 51 and the copper foil 50 below the plating resist 52 are removed. As shown in FIG. 14, the remaining electrolytic plating film 53 and electroless plating film 51 and the copper foil 50 form the first conductor layer 24 on the first insulating resin layer 23 and the second conductor layer 34 on the second insulating resin layer 33. A microstrip line 26 is formed by the outermost conductor layer 16A and the first conductor layer 24 arranged on the outermost side on the first surface 21F side of the conductor layer 16 of the base substrate portion 21, and the outermost conductor layer 16 is formed. The high frequency substrate portion 27 is formed by the conductor layer 16 </ b> A, the first insulating resin layer 23, and the first conductor layer 24.

  (21) As shown in FIG. 15, a solder resist layer 37 is laminated on the second conductor layer 34. Next, an opening 37 A is formed in the solder resist layer 37 by photolithography, and a pad 38 is formed in the second conductor layer 34. Thus, the printed wiring board 10 shown in FIG. 1 is completed.

  The description regarding the manufacturing method of the printed wiring board 10 of this embodiment is above. Next, the effect of the printed wiring board 10 and the manufacturing method thereof will be described.

  The printed wiring board 10 of the present embodiment includes an outermost conductor layer 16A, a first insulating resin layer 23, a first conductor layer 24, and the outermost conductor layer 16A that are disposed on the first surface 21F side of the base substrate portion 21. As a result, a high frequency substrate portion 27 having a higher frequency characteristic than that of the base substrate portion 21 is formed. The printed wiring board 10 having the high-frequency board portion 27 has the first insulating resin layer 23 laminated on the first surface 21F of the base substrate portion 21, and the second insulating resin layer 33 laminated on the second surface 21S. Thereafter, the first conductor layer 24 is formed on the first insulating resin layer 23, and the second conductor layer 34 is formed on the second insulating resin layer 33. In such a method of manufacturing the printed wiring board 10, the high-frequency substrate portion 27 is formed by building up the first insulating resin layer 23 and the first conductor layer 24 on the first surface 21 </ b> F of the base substrate portion 21. As compared with the case where the printed circuit board 10 is manufactured by separately preparing the base board and the high frequency board and bonding the base board and the high frequency board, the printed wiring board 10 can be easily manufactured.

  In the printed wiring board 10 of the present embodiment, the number of conductor layers laminated on the first surface 21F side of the base substrate portion 21 (that is, the number of first conductor layers 24) and the layer laminated on the second surface 21S side. Since the number of conductor layers to be formed (that is, the number of second conductor layers 34) is the same, the symmetry of the printed wiring board 10 can be improved in the thickness direction.

  In the present embodiment, for example, the base substrate unit 21 and the high frequency substrate unit 27 can have different functions such that the high frequency substrate unit 27 is an antenna substrate and the base substrate unit 21 is a digital signal processing substrate. It becomes. In this case, the dielectric loss tangent of the first insulating resin layer 23 is smaller than the dielectric loss tangent of the insulating base material 11K and the interlayer insulating resin layer 15 of the base substrate portion 21, and is 0.001 to 0.005. It is preferable. The thickness of the first insulating resin layer 23 is preferably larger than any thickness of the insulating base material 11K, the interlayer insulating resin layer 15 and the second insulating resin layer 33.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various modifications are possible within the scope of the invention other than the following. It can be changed and implemented.

  (1) In the above embodiment, as long as the dielectric tangent of the first insulating resin layer 23 is sufficiently low, the thickness of the first insulating resin layer 23 may be substantially the same as the thickness of the interlayer insulating resin layer 15.

  (2) Although the thickness of the second insulating resin layer 33 is substantially the same as the thickness of the interlayer insulating resin layer 15 in the above embodiment, it may be different.

  (3) In the above embodiment, the thickness of the insulating substrate 11K may be the same as or different from the thickness of the interlayer insulating resin layer 15. In addition, when the thickness of the insulating base material 11K is large, the conductor layers 12 and 12 may be connected by a through-hole conductor that penetrates the insulating base material 11K.

10 Printed wiring board 11K Insulating substrate (insulating resin layer)
12 Conductor layers 15 Interlayer insulating resin layer (insulating resin layer)
16 conductor layer 21 base substrate portion 23 first insulating resin layer 24 first conductor layer 27 high frequency substrate portion 33 second insulating resin layer 34 second conductor layer

Claims (15)

A base substrate portion in which conductor layers and insulating resin layers are alternately laminated;
A first insulating resin layer laminated on a first surface which is a surface on one side of the front and back of the base substrate portion;
A first conductor layer laminated on the first insulating resin layer;
A second insulating resin layer laminated on a second surface which is the other side surface of the base substrate portion;
A second conductor layer laminated on the second insulating resin layer,
The first insulating resin layer is made of a resin material that has better high frequency characteristics than the second insulating resin layer,
Printed wiring further comprising a high-frequency substrate portion including the conductor layer disposed on the outermost side on the first surface side of the base substrate portion, the first insulating resin layer, and the first conductor layer. Board. The printed wiring board according to claim 1,
The dielectric tangent of the first insulating resin layer is smaller than the dielectric tangent of the second insulating resin layer and is 0.001 to 0.005. The printed wiring board according to claim 1 or 2,
The thickness of the first insulating resin layer is larger than the thickness of the second insulating resin layer. The printed wiring board according to any one of claims 1 to 3,
The number of conductor layers laminated on the first surface side of the base substrate portion is the same as the number of conductor layers laminated on the second surface side of the base substrate portion. The printed wiring board according to any one of claims 1 to 4,
The dielectric tangent of the first insulating resin layer is smaller than the dielectric tangent of each insulating resin layer included in the base substrate portion. The printed wiring board according to claim 5,
The thickness of the first insulating resin layer is larger than the thickness of each insulating resin layer included in the base substrate portion. The printed wiring board according to any one of claims 1 to 6,
The high-frequency substrate unit has a microstrip line formed by a conductor layer disposed on the outermost side on the first surface side of the base substrate unit and the first conductor layer. A printed wiring board according to any one of claims 1 to 7,
A solder resist layer is laminated on the second conductor layer,
A solder resist layer is not laminated on the first conductor layer. Forming a base substrate portion in which conductor layers and insulating resin layers are alternately laminated;
Laminating a first insulating resin layer on a first surface that is one surface of the front and back sides of the base substrate portion;
Forming a first conductor layer on the first insulating resin layer;
Laminating a second insulating resin layer on the second surface, which is the surface on the other side of the front and back sides of the base substrate portion;
Forming a second conductor layer on the second insulating resin layer, and a printed wiring board manufacturing method comprising:
The lamination of the first insulating resin layer is performed in the same process as the lamination of the second insulating resin layer,
Using the insulating resin layer having higher frequency characteristics than the second insulating resin layer as the first insulating resin layer, the conductor layer disposed on the outermost side on the first surface side of the base substrate portion, A method for manufacturing a printed wiring board, which forms a high-frequency substrate portion comprising a first insulating resin layer and the first conductor layer. It is a manufacturing method of the printed wiring board according to claim 9,
The dielectric tangent of the first insulating resin layer is smaller than the dielectric tangent of the second insulating resin layer and is 0.001 to 0.005. It is a manufacturing method of the printed wiring board according to claim 9 or 10,
The thickness of the first insulating resin layer is larger than the thickness of the second insulating resin layer. A method of manufacturing a printed wiring board according to any one of claims 9 to 11,
The dielectric tangent of the first insulating resin layer is smaller than the dielectric tangent of each insulating resin layer included in the base substrate portion. It is a manufacturing method of the printed wiring board according to claim 12,
The thickness of the first insulating resin layer is larger than the thickness of each insulating resin layer included in the base substrate portion. A method for manufacturing a printed wiring board according to any one of claims 9 to 13,
In forming the high-frequency substrate portion, a microstrip line is formed by the conductor layer and the first conductor layer disposed on the outermost side on the first surface side of the base substrate portion. A method of manufacturing a printed wiring board according to any one of claims 9 to 14,
A solder resist layer is laminated only on the second conductor layer.

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