JP2023074860A - Manufacturing method for printed wiring board - Google Patents

Abstract

To provide a manufacturing method for a printed wiring board with high quality.SOLUTION: A manufacturing method for a printed wiring board includes: forming, on an insulation layer 4, a conductor layer 10 with a conductor circuit; preparing a forming member 40 having a thermosetting resin insulation layer 20 with a first surface 20F and a second surface 20B on a side opposite to the first surface, and a first protective film 42 formed on the first surface of the resin insulation layer 20; and sticking the forming member 40 on the conductor layer 10 so that the conductor circuit and the second surface 20b make contact with each other. When the resin insulation layer 20 and the first protective film 42 are projected with light perpendicular to the first surface 20F, each side of the outer peripheral edge of the first protective film 42 exists outside of each side of the insulation layer 20.SELECTED DRAWING: Figure 2D

Description

The technology disclosed by this specification relates to a method for manufacturing a printed wiring board.

Patent Document 1 discloses a process of preparing an insulating layer forming member having a semi-cured insulating layer provided on one surface of a support film, and placing the insulating layer forming member so that the pad and the semi-cured insulating layer are in contact with each other. Disclosed is a method for manufacturing a wiring board, which includes a step of attaching and a step of curing the insulating layer after the insulating layer forming member is attached.

JP 2009-99649 A

[Problem of Patent Document 1]
In the technique of Patent Document 1, it is considered that the support film and the semi-cured insulating layer are pressed when the insulating layer forming member is attached. It is thought that part of the semi-cured insulating layer protrudes outward from the peripheral edge of the support film due to the application of pressure. A portion of the protruding insulating layer is called a bleed. Part of the bleed is believed to protrude above the support film. If the bleed protrudes upward, it is considered that the flatness of the wiring substrate is impaired. As a result, it is considered that the quality of the wiring board is degraded.

A method for manufacturing a printed wiring board of the present invention includes forming a conductor layer having a conductor circuit on an insulating layer, and thermosetting resin having a first surface and a second surface opposite to the first surface. preparing a forming member having an insulating layer and a first protective film formed on the first surface of the resin insulating layer; and affixing the forming member. When the resin insulating layer and the first protective film are projected with light perpendicular to the first surface, each side of the outer peripheral edge of the first protective film exists outside each side of the resin insulating layer. .

In the manufacturing method of the embodiment of the present invention, the forming member is attached onto the conductor layer so that the conductor circuit and the second surface are in contact with each other. When the resin insulating layer and the first protective film are projected with light perpendicular to the first surface, each side of the outer peripheral edge of the first protective film exists outside each side of the resin insulating layer. Therefore, when the forming member is attached onto the conductor layer, part of the resin insulation layer is prevented from protruding outward from the outer peripheral edge of the first protective film. Part of the resin insulation layer is prevented from protruding above the first protective film. Impairment of the flatness of the printed wiring board manufactured by the manufacturing method of the present invention is suppressed. A high quality printed wiring board is provided.

BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows typically the printed wiring board of embodiment. FIG. 4 is a cross-sectional view schematically showing a method for manufacturing a printed wiring board according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a method for manufacturing a printed wiring board according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a method for manufacturing a printed wiring board according to the embodiment; FIG. 4 is a plan view schematically showing a method for manufacturing a printed wiring board according to the embodiment; 2D is a plan view of the forming member 40 of FIG. 2D; FIG. FIG. 4 is a cross-sectional view schematically showing a method for manufacturing a printed wiring board according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a method for manufacturing a printed wiring board according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a method for manufacturing a printed wiring board according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a method for manufacturing a printed wiring board according to the embodiment; FIG. 4 is a cross-sectional view schematically showing a method for manufacturing a printed wiring board according to the embodiment; Sectional drawing which shows typically the manufacturing method of the printed wiring board of a modification.

[Embodiment]
FIG. 1 is a cross-sectional view showing a printed wiring board 2 of the embodiment. As shown in FIG. 1 , printed wiring board 2 has insulating layer 4 , first conductor layer 10 , resin insulating layer 20 , second conductor layer 60 and via conductors 70 .

The insulating layer 4 is formed using a thermosetting resin. The insulating layer 4 may contain inorganic particles such as silica. The insulating layer 4 may contain a reinforcing material such as glass cloth.

A first conductor layer 10 is formed on the insulating layer 4 . The first conductor layer 10 includes pads 12 and signal wirings 14 . Although not shown, the first conductor layer 10 also includes conductor circuits other than the pads 12 and the signal wirings 14 . The first conductor layer 10 is made of copper. The first conductor layer 10 is formed of a seed layer 10a and an electroplated film 10b on the seed layer 10a.

Resin insulation layer 20 is formed on insulation layer 4 and first conductor layer 10 . Resin insulation layer 20 has a first surface 20F (upper surface in the drawing) and a second surface 20B (lower surface in the drawing) opposite to first surface 20F. Openings 22 exposing pads 12 are formed in resin insulation layer 20 . Resin insulation layer 20 is made of a thermosetting resin. Thermosetting resins include epoxy-based resins, polymer-based resins, and inorganic fillers.

Second conductor layer 60 is formed on first surface (20F) of resin insulation layer 20 . The second conductor layer 60 includes lands 62 and signal wirings 64 . Although not shown, the second conductor layer 60 also includes conductor circuits other than the lands 62 and the signal wirings 64 . The second conductor layer 60 is made of copper. The second conductor layer 60 is formed of a seed layer 60a and an electroplated film 60b on the seed layer 60a.

Via conductors 70 are formed in openings 22 . Via conductors 70 connect first conductor layer 10 and second conductor layer 60 . In FIG. 1, via conductors 70 connect pads 12 and lands 62 . Via conductor 70 is formed of seed layer 60a and electrolytic plated film 60b on seed layer 60a.

[Manufacturing Method of Printed Wiring Board 2 of Embodiment]
2A to 2J show a method for manufacturing the printed wiring board 2 of the embodiment. 2A-2D and 2F-2J are cross-sectional views. FIG. 2E is a plan view of the forming member 40 shown in FIG. 2D.

FIG. 2A shows the insulating layer 4 and the first conductor layer 10 formed on the insulating layer 4 . The first conductor layer 10 is formed by a semi-additive method.

As shown in FIG. 2B, first intermediate member 30 having resin insulation layer 20 and second protective film 32 formed on second surface 20B of resin insulation layer 20 is prepared. At this point, resin insulation layer 20 is in a semi-cured state. Second protective film 32 completely covers second surface 20B of resin insulation layer 20 . When first intermediate member 30 is viewed from above, each side of the outer periphery of second protective film 32 overlaps with each side of the outer periphery of resin insulation layer 20 . That is, when the resin insulation layer 20 and the second protective film 32 are projected with light perpendicular to the first surface 20</b>F of the resin insulation layer 20 , each side of the outer peripheral edge of the second protective film 32 and the outside of the resin insulation layer 20 are projected. Each side of the perimeter overlaps. An example of the second protective film 32 is a film made of polyethylene terephthalate (PET). A release agent is formed between the second protective film 32 and the resin insulation layer 20 .

As shown in FIG. 2C, first protective film 42 is attached on first surface (20F) of resin insulation layer 20 . First protective film 42 is larger than resin insulation layer 20 as will be described in detail later. The first protective film 42 completely covers the first surface 20F. An example of the first protective film 42 is a film made of polyethylene terephthalate (PET). A release agent is formed between first protective film 42 and resin insulation layer 20 .

As shown in FIG. 2D, second protective film 32 is removed from second surface 20B of resin insulation layer 20 . As a result, forming member 40 having resin insulating layer 20 and first protective film 42 is prepared. As shown in FIG. 2E , when forming member 40 is viewed from above, each side of the outer periphery of first protective film 42 is present outside each side of the outer periphery of resin insulation layer 20 . That is, when the resin insulation layer 20 and the first protective film 42 are projected with light perpendicular to the first surface 20</b>F of the resin insulation layer 20 , each side of the outer peripheral edge of the first protective film 42 is outside the resin insulation layer 20 . It exists outside each side of the periphery.

As shown in FIG. 2F, the forming member 40 is attached on the insulating layer 4 and the first conductor layer 10 so that the second surface 20B contacts the pads 12 and the signal wirings 14 of the first conductor layer 10 . At this time, heat and pressure are applied to the first protective film 42 and the semi-cured resin insulation layer 20 . First protective film 42 and resin insulating layer 20 are pressed in a direction toward insulating layer 4 by pressure plate 50 arranged on first protective film 42 . The pressure plate 50 is, for example, a SUS (stainless steel) plate. By attaching the forming member 30, the semi-cured resin insulation layer 20 is deformed. In the embodiment, each side of the outer periphery of the first protective film 42 exists outside each side of the resin insulation layer 20 (see FIG. 2E). Therefore, when forming member 40 is attached, part of resin insulation layer 20 is prevented from protruding outward from the outer peripheral edge of first protective film 42 . That is, bleeding does not occur. Therefore, part of resin insulation layer 20 does not protrude above first protective film 42 . Heating of the resin insulation layer 20 is performed by a heating mechanism (not shown). Hardening of the resin insulation layer 20 progresses by heating.

As shown in FIG. 2G, laser light L is irradiated from above the first protective film 42 . The laser light L penetrates the first protective film 42 and the resin insulation layer 20 at the same time. A via-conductor opening 22 is formed to reach the pad 12 of the first conductor layer 10 . The laser light L is, for example, UV laser light or CO2 laser light. Pads 12 are exposed through openings 22 .

As shown in FIG. 2H, first protective film 42 is removed from first surface (20F) of resin insulation layer 20 .

As shown in FIG. 2I, seed layer 60a is formed on first surface (20F) of resin insulation layer 20 . The seed layer 60a is formed by electroless plating. A plating resist 100 is formed on the seed layer 60a. The plating resist 100 has openings for forming the lands 62 and the signal wirings 64 (FIG. 1).

Electroplated film 60b is formed on seed layer 60a exposed from plating resist 100, as shown in FIG. 2J. Electroplated film 60 b fills opening 22 . A land 62 and a signal wiring 64 are formed by the seed layer 60a and the electroplated film 60b on the first surface 20F. A second conductor layer 60 is formed. Seed layer 60 a and electrolytic plated film 60 b in opening 22 form via conductor 70 . Via conductors 70 connect pads 12 and lands 62 .

After that, the plating resist 100 is removed. The seed layer 60a exposed from the electrolytic plated film 60b is removed. The second conductor layer 60 and via conductors 70 are formed at the same time. A heat treatment is applied to completely harden the resin insulation layer 20 . A printed wiring board 2 (FIG. 1) of the embodiment is obtained.

According to the manufacturing method of the embodiment, when the forming member 40 is attached, part of the resin insulation layer 20 is prevented from protruding outward from the outer peripheral edge of the first protective film 42 . Bleed does not occur. Part of resin insulation layer 20 does not protrude above first protective film 42 . Therefore, deterioration of the flatness of the printed wiring board 2 manufactured by the manufacturing method of the embodiment is suppressed. A high quality printed wiring board 2 is provided.

[Modified example of embodiment]
In a modification, the printed wiring board 2 obtained is the same as the embodiment (FIG. 1). In the modified example, part of the manufacturing method differs from the embodiment.

As shown in FIG. 3, in the modified example, instead of first intermediate member 30 (FIGS. 2B and 2C), resin insulation layer 20 and a first protection layer formed on first surface (20F) of resin insulation layer 20 are formed. A second intermediate member 130 having a membrane 42 is provided. At this point, resin insulation layer 20 is in a semi-cured state. First protective film 42 completely covers first surface (20F) of resin insulation layer 20 . When second intermediate member 130 is viewed from above, each side of the outer peripheral edge of first protective film 42 overlaps each side of the outer peripheral edge of resin insulation layer 20 . That is, when the resin insulation layer 20 and the first protective film 42 are projected with light perpendicular to the first surface 20</b>F of the resin insulation layer 20 , each side of the outer peripheral edge of the first protective film 42 and the outside of the resin insulation layer 20 are projected. Each side of the perimeter overlaps.

Subsequently, outer peripheral edge portion 200 of resin insulation layer 20 is removed. Outer peripheral edge portion 200 is a portion of resin insulation layer 20 outside the dashed line in FIG. 3 . For example, the outer peripheral edge 200 is removed by laser light. Removal of the outer peripheral edge 200 may be done in other ways. In a modification, the outer peripheral edge 200 is removed to form the forming member 40 shown in Figures 2D and 2E. The steps after attaching the forming member 40 are the same as the steps shown in FIGS. 2F to 2J of the embodiment.

2: Printed wiring board 4: Insulating layer 10: First conductor layer 12: Pad 14: Signal wiring 20: Resin insulating layer 20F: First surface 20B: Second surface 30: First intermediate member 32: Second protective film 40 : forming member 42 : first protective film 130 : second intermediate member 200 : outer peripheral edge

Claims (4)

forming a conductor layer having a conductor circuit on the insulating layer;
a forming member having a thermosetting resin insulation layer having a first surface and a second surface opposite to the first surface; and a first protective film formed on the first surface of the resin insulation layer to prepare and
affixing the forming member on the conductor layer so that the conductor circuit and the second surface are in contact with each other, the printed wiring board manufacturing method comprising:
When the resin insulating layer and the first protective film are projected with light perpendicular to the first surface, each side of the outer peripheral edge of the first protective film exists outside each side of the resin insulating layer. . 2. The method of manufacturing a printed wiring board according to claim 1, wherein said preparing comprises a first intermediate member having said resin insulation layer and a second protective film formed on said second surface of said resin insulation layer. affixing the first protective film on the first surface; and removing the second protective film from the second surface after the first protective film is affixed. and when the resin insulation layer and the second protective film are projected with light perpendicular to the first surface, each side of the outer peripheral edge of the second protective film overlaps each side of the resin insulation layer . 2. The method of manufacturing a printed wiring board according to claim 1, wherein said preparing includes said resin insulating layer and said first protective film formed on said first surface of said resin insulating layer, and said When the resin insulation layer and the first protective film are projected with light perpendicular to the first surface, each side of the outer peripheral edge of the first protective film overlaps with each side of the resin insulation layer. preparing a member; and removing an outer peripheral edge portion of the resin insulation layer of the second intermediate member. 2. The method of manufacturing a printed wiring board according to claim 1, wherein said pasting includes applying heat and pressure to said first protective film and said resin insulation layer.

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