JP7453509B2 - Printed wiring board and printed wiring board manufacturing method - Google Patents

Description

The present invention relates to a printed wiring board having a glass plate as a core substrate, and a method for manufacturing the printed wiring board.

Patent Document 1 discloses printed wiring in which an insulating layer and a conductive layer are formed on a large glass plate, both sides of the glass plate are connected using through holes to form a circuit board, and then the large glass plate is cut into individual pieces. Discloses a method for manufacturing a board.

JP2019-192722A

[Issue of Patent Document 1]
In Patent Document 1, since an insulating layer and a conductive layer are formed on a glass plate, it is considered difficult to improve the positional accuracy of wiring. In order to improve the positioning accuracy of the wiring, an opening is created in the center of the insulating substrate and a glass plate is housed in the opening. By using alignment marks provided on the insulating substrate, an insulating layer and a conductive layer are formed on the glass plate. It is possible to do so. However, in this method, since a frame-shaped insulating substrate is placed around the glass plate, there is a possibility that warping may occur due to the difference in coefficient of thermal expansion between the glass plate and the insulating substrate.

The printed wiring board according to the present invention includes a core substrate formed by accommodating a glass plate in a rectangular opening of an insulating substrate, and a build-up layer formed on the core substrate and formed from a resin insulating layer and a conductor layer. have The insulating substrate is formed in a frame shape around the opening, and four slits are provided at corners of the opening of the insulating substrate to divide the frame-shaped insulating substrate into four parts ,
The space between the glass plate and the opening and the inside of the four slits are filled with resin.

The printed wiring board according to the present invention includes a core substrate formed by accommodating a glass plate in a rectangular opening of an insulating substrate, and a build-up layer formed on the core substrate and formed from a resin insulating layer and a conductor layer. have In the method for manufacturing a printed wiring board according to the present invention, a rectangular opening is provided in a large insulating substrate, a slit is provided at a corner of the opening, a glass plate is accommodated in the opening, and the glass plate and the Filling resin between the openings and in the four slits, cutting the large insulating substrate along the edges of the slits to make an oval insulating substrate, and cutting the large insulating substrate into an oval insulating substrate by the slits. It has 4 separations.

[Effects of embodiment]
According to the printed wiring board and the method for manufacturing a printed wiring board according to the embodiment of the present invention, since a conductor layer is formed by housing a glass plate in an opening of an insulating substrate, wiring position accuracy can be improved. Four slits are provided at the corners of the opening of the insulating substrate to divide the frame-shaped insulating substrate into four sections. Since the insulating substrate is not in the shape of a frame but in the shape of four separate rods, even if the thermal expansion coefficients of the glass plate and the insulating substrate are different, the stress generated on the insulating substrate is divided into four, and the stress from the insulating substrate is divided into four parts. There is no possibility of warping the printed wiring board.

FIG. 1(A) is a cross-sectional view of the printed wiring board of the first embodiment, and FIG. 1(B) is a plan view. FIG. 1 is a plan view of a printed wiring board according to a first embodiment of the present invention. It is a manufacturing process diagram of the printed wiring board of 1st Embodiment. It is a manufacturing process diagram of the printed wiring board of 1st Embodiment. It is a manufacturing process diagram of the printed wiring board of 2nd Embodiment. FIG. 3 is a cross-sectional view of a printed wiring board according to a second embodiment.

[First embodiment]
FIG. 1(A) is a cross-sectional view of a printed wiring board 10 of the first embodiment. FIG. 1(B) is a plan view of the printed wiring board 10, and FIG. 1(A) corresponds to the A1-A1 cross section in FIG. 1(B). The printed wiring board 10 includes a core substrate 30 having a first surface FF and a second surface SS opposite to the first surface FF, and a first buildup layer 55F formed on the first surface FF of the core substrate. It has a second buildup layer 55S formed on the second surface SS of the core substrate.

The core substrate 30 includes a frame-shaped insulating substrate 22 having an opening 22a shown in FIG. A glass plate 20 having a surface F and a second surface S opposite to the first surface F, an insulating substrate 22 shown in FIG. 1(A), and a first insulating layer on the first surface F of the glass plate 20. 28F, a second insulating layer 28S on the second surface S of the insulating substrate 22 and the glass plate 20, a first conductor layer 34F formed on the first insulating layer 28F, and a second insulating layer 28S formed on the second insulating layer 28F. The second conductor layer 34S has a second conductor layer 34S, and a through-hole conductor 36 connects the first conductor layer 34F and the second conductor layer 34S. The through-hole conductor 36 is formed in the through-hole 26 formed in the resin 28 derived from the first insulating layer 28F and the second insulating layer 28S filled in the through-hole 25 formed in the glass plate 20. . Alignment marks 24 for forming a conductor layer are formed on the insulating substrate 22.

The first buildup layer 55F includes a first resin insulating layer 50F formed on the first surface F of the core substrate 30 and the first conductor layer 34F, and a third resin insulating layer 50F formed on the first resin insulating layer 50F. It has a conductor layer 58F. The first buildup layer 55F further includes a first via conductor 60F that penetrates the first resin insulating layer 50F. The first via conductor 60F connects the first conductor layer 34F and the third conductor layer 58F.

A first solder resist layer 70F having an opening 72F is formed on the first resin insulating layer 50F and the third conductor layer 58F. First solder bumps 76F for mounting electronic components are formed on the third conductor layer 58F exposed from the opening 72F.

The second buildup layer 55S includes a second resin insulating layer 50S formed on the second surface S of the core substrate 30 and the second conductor layer 34S, and a second resin insulating layer 50S formed on the second resin insulating layer 50S. 4 conductor layers 58S. The second buildup layer 55S further includes a second via conductor 60S that penetrates the second resin insulating layer 50S. The second via conductor 60S connects the second conductor layer 34S and the fourth conductor layer 58S.

A second solder resist layer 70S having an opening 72S is formed on the second resin insulating layer 50S and the fourth conductor layer 58S. A second solder bump 76S for connection to a circuit board such as a motherboard is formed on the fourth conductor layer 58S exposed from the opening 72S.

In the printed wiring board 10 of the first embodiment, a glass plate 20 is accommodated in an opening 22a of an insulating substrate 22, and a first conductor layer 34F, a second conductor layer 34S, a third conductor layer 58F, and a fourth conductor layer 58S are formed. Therefore, by using the alignment mark 24 on the first surface F side of the insulating substrate 22 (and the alignment mark on the second surface side, not shown), the first conductor layer 34F, the second conductor layer 34S, and the third conductor layer The positional accuracy of the layer 58F and the fourth conductor layer 58S can be increased.

In the printed wiring board 10 of the first embodiment, as shown in FIG. 1(B), four slits 22b are provided at the corners of the opening 22a of the insulating substrate 22, dividing the frame-shaped insulating substrate into four parts. There is. As shown in FIG. 1A, the space between the opening 22a of the insulating substrate 22 and the glass plate 20 is filled with resin 28 derived from the first insulating layer 28F and the second insulating layer 28S. Similarly, the slit 22b is filled with resin 28 derived from the first insulating layer 28F and the second insulating layer 28S. In the printed wiring board 10 of the first embodiment, the insulating substrate 22 is not frame-shaped but consists of four separate rod-shaped insulating substrates (child pieces) 22z, so the difference in thermal expansion coefficient between the glass plate and the insulating substrate Even if the insulating substrate 22 is insulated, the stress generated in the insulating substrate 22 is divided into four parts, and the stress from the insulating substrate 22 does not cause the printed wiring board 10 to warp.

[Method for manufacturing printed wiring board of first embodiment]
A large-sized insulating substrate 122 shown in FIG. 2 is prepared, and a rectangular opening 22a and a slit 22b are formed at the corner of the opening 22a. A cross section of the opening 22a in FIG. 2 is shown in FIG. 3(A). A glass plate 20 is prepared and accommodated in the opening 22a of the insulating substrate 122 (FIG. 3(B)). Glass plate 20 is comprised of pure silicon dioxide (approximately 100% SiO2), soda lime glass, borosilicate glass, aluminosilicate glass, fluoroglass, phosphate glass, or chalcogen glass. The front and back surfaces of the glass plate are roughened to Ra (average roughness) of approximately 100 nm by blasting or the like in advance.

A through hole 25 for forming a through hole is formed in the glass plate 20 using an alignment mark (not shown) of the insulating substrate 122 as a reference (FIG. 3(C)). The measured position of the alignment mark is also used in subsequent formation of the conductor layer. A first insulating layer 28F is formed on the first surface F of the insulating substrate 122 and the glass plate 20, and a second insulating layer 28S is formed on the second surface S, and the opening of the insulating substrate 22 shown in FIG. 1(B) is formed. Resin 28 derived from the first insulating layer 28F and the second insulating layer 28S is filled between the glass plate 22a and the glass plate 20, in the four slits 22b, and in the through holes 25. Then, a through hole 26 for a through hole is formed in the first insulating layer 28F, the resin 28 in the through hole 25 of the glass plate 20, and the second insulating layer 28S (FIG. 3(D)). As described above, since the front and back surfaces of the glass plate are roughened, the adhesion between the glass plate 20 and the first insulating layer 28F and the second insulating layer 28S is high.

An electroless plating film 32 is formed on the surfaces of the first insulating layer 28F and the second insulating layer 28S and inside the through hole 26 by electroless plating (FIG. 3(E)). A plating resist 40 having a predetermined pattern is formed on the electroless plating film 32 , and by electrolytic plating, an electrolytic plating film 38 is formed on the electroless plating film 32 exposed from the plating resist 40 . A plating film is filled to form a through-hole conductor 36 (FIG. 3(F)). The plating resist is removed, the electroless plating film 32 exposed from the electrolytic plating film 38 is removed, the first conductor layer 34F and the second conductor layer 34S are formed, and the core substrate 30 is completed (FIG. 3(G)). . The core substrate 30 has a first surface FF in the same direction as the first surface F of the glass plate 20 and a second surface SS in the same direction as the second surface S of the glass plate 20 .

A first resin insulating layer 50F is formed on the first surface FF of the core substrate 30, and a second resin insulating layer 50S is formed on the second surface SS (FIG. 4(A)). An opening 51F reaching the first conductor layer 34F is formed in the first resin insulating layer 50F, and an opening 51S reaching the second conductor layer 34S is formed in the second resin insulating layer 50S (FIG. 4(B)). By electroless plating, an electroless plating film 52 is formed on the surfaces of the first resin insulating layer 50F and the second resin insulating layer 50S and in the openings 51F and 51S, and a predetermined plating resist (not shown) is formed. An electrolytic plated film 56 is formed on the electroless plated film 52 exposed from the opening 51F, and a first via conductor 60F is formed in the opening 51F, and a second via conductor 60S is formed in the opening 51S. The plating resist is peeled off and the electroless plated film 52 exposed from the electrolytic plated film 56 is removed to form a third conductor layer 58F and a fourth conductor layer 58S (FIG. 4(C)).

A first solder resist layer 70F having a first opening 72F is formed on the third conductor layer 58F and the first resin insulating layer 50F. A second solder resist layer 70S having a second opening 72S is formed on the fourth conductor layer 58S and the second resin insulating layer 50S. The large insulating substrate 122 is cut along the cutting line 22c along the edge of the slit 22b shown in FIG. 2 to form individual pieces (small) of the insulating substrate 22 (FIG. 4(D)). At this time, as shown in FIG. 1(B), the oval insulating substrate 22 is divided into four parts by the slit 22b, and four rod-shaped insulating substrates (child pieces) 22z are connected by the resin 28 in the slit 22b. The state will be as follows. . A first solder bump 76F is formed in the first opening 72F of the first solder resist layer 70F, and a second solder bump 76S is formed in the second opening 72S of the second solder resist layer 70S (FIG. 1(A)).

In the printed wiring board manufacturing method of the first embodiment, the insulating substrate 22 is composed of four separate rod-shaped insulating substrates (child pieces) 22z, and therefore the glass plate and the insulating substrate have different coefficients of thermal expansion. However, the stress generated in the insulating substrate 22 is divided into four parts, and the stress from the insulating substrate 22 does not cause the printed wiring board 10 to warp.

[Second embodiment]
FIG. 6 is a sectional view of the printed wiring board of the second embodiment.
In the printed wiring board 10 of the second embodiment, the core substrate 30 includes a glass plate 20, a first conductor layer 34F formed on the first surface F of the glass plate 20, and a second conductor layer formed on the second surface S. 34S, and a through-hole conductor 36 connecting the first conductor layer 34F and the second conductor layer 34S. The space between the opening 22a of the insulating substrate 22 and the glass plate 20 and the inside of the slit (not shown) are filled with resin 50 derived from the first resin insulating layer 50F and the second resin insulating layer 50S.

[Method for manufacturing printed wiring board of second embodiment]
A glass plate 20 shown in FIG. 5(A) is prepared. The first surface F and second surface S of the glass plate 20 are roughened to Ra (average roughness) of approximately 100 nm by blasting or the like. A through hole 26 for a through hole is formed in the glass plate 20 (FIG. 5(B)). An electroless plating film 32 is formed on the surface of the glass plate 20 and inside the through hole 26 by electroless plating. A plating resist 40 having a predetermined pattern is formed on the electroless plating film 32 , and by electrolytic plating, an electrolytic plating film 38 is formed on the electroless plating film 32 exposed from the plating resist 40 . A plating film is filled to form a through-hole conductor 36 (FIG. 5(C)). The plating resist is removed, and the electroless plated film 32 exposed from the electrolytic plated film 38 is removed to form a first conductor layer 34F and a second conductor layer 34S (FIG. 5(D)). Similar to the first embodiment described above with reference to FIG. 2, the glass plate 20 shown in FIG. (Fig. 5(E)). At this time, the glass plate 20 is aligned with reference to alignment marks (not shown) provided on the insulating substrate 22. The subsequent steps are similar to those in the first embodiment.

20 glass plate 22 insulating substrate 22a opening 22b slit 30 core substrate 34F first conductor layer 34S second conductor layer 36 through-hole conductor

Claims (3)

A printed wiring board having a core substrate formed by accommodating a glass plate in a rectangular opening of an insulating substrate, and a build-up layer formed on the core substrate and formed of a resin insulating layer and a conductor layer,
The insulating substrate is formed in a frame shape around the opening,
Four slits are provided at the corners of the opening of the insulating substrate, dividing the frame-shaped insulating substrate into four parts ,
The space between the glass plate and the opening and the inside of the four slits are filled with resin. The printed wiring board according to claim 1 ,
The resin is the origin of the resin insulating layer on the insulating substrate and the glass plate. A method for manufacturing a printed wiring board comprising: a core substrate having a glass plate accommodated in a rectangular opening of the insulating substrate; and a build-up layer formed on the core substrate comprising a resin insulating layer and a conductor layer. hand,
Providing a rectangular opening in a large insulating substrate and a slit at a corner of the opening;
accommodating a glass plate in the opening;
filling a resin between the glass plate and the opening and into the four slits;
The large- sized insulating substrate is cut along the edge of the slit to form a small-sized insulating substrate, and the small-sized insulating substrate is divided into four parts by the slit.

Images