WO2015083222A1 - Multilayer substrate and manufacturing method for same - Google Patents

Abstract

The purpose of the present invention is to provide a multilayer substrate which can accommodate next-generation high-speed transmission methods, and is thinner than at present in order to conserve space regardless of whether a flexible circuit board or rigid circuit board is used. This multilayer substrate, in which a conducting layer and an insulating layer are alternately stacked, has a multilayer structure in which a thermoplastic resin as an insulating layer and a thermosetting dielectric resin are alternately sequentially stacked.

Description

Multilayer substrate and method of manufacturing the same

The present invention relates to a multilayer substrate and a method of manufacturing the same, and more particularly to a thin multilayer substrate that can handle next-generation high-speed transmission and a method of manufacturing the same.

A flexible printed circuit board (FPC: Flexible Printed Circuit) is a printed circuit board (substrate) having a structure that can be bent using a thin insulating material. On the other hand, generally speaking, a substrate refers to a rigid wiring board (hard substrate). The rigid wiring board is a hard board on which components are mounted to form a circuit, and has a structure that does not bend. There is also a rigid flexible wiring board in which a rigid wiring board and a flexible wiring board are combined.

Flexible wiring boards or rigid flexible wiring boards are thin and soft characteristics that can be bent or broken, and thus enable three-dimensional wiring and movable part wiring in equipment. For this reason, flexible wiring boards or rigid flexible wiring boards are widely used in familiar electronic devices, and are indispensable for reducing the size and weight of electronic devices such as mobile phones and liquid crystal televisions. .

There is a demand for a substrate that has a thickness t of 0.5 mm or less and a signal frequency of 10 GHz or more for 10 layers for the next-generation PC. This is because, with the recent reduction in thickness of electronic devices, the occupied space for arranging the main substrate is reduced, so that it is necessary to reduce the thickness of the main substrate in order to reduce the thickness of the product. Furthermore, it is necessary to cope with high-speed transmission of a next-generation high-speed transmission module, for example, an optical communication module (20 GHz or more) or millimeter wave (60 GHz or more).

Patent No. 4038206 Patent 2788701 gazette

Currently, rigid wiring boards have 10 layers and a standard thickness Std. The limit is t = 0.8 mm, the thinnest at around 0.68 mm. In addition, in the case of a flexible wiring board, there is a method of using a liquid crystal polymer as a base material (see Patent Document 1), but since the liquid crystal polymer is a thermoplastic resin, it is difficult to sequentially laminate and thin There is a problem of being

As another flexible wiring board, a multilayer wiring board is also known which uses a polyimide-based resin as a base material and uses a polyimide-based adhesive sheet as an adhesive sheet (see Patent Document 2). In order to make a flexible wiring board for high-speed transmission, excellent transmission characteristics of high frequency signals, stable low reactance, excellent transmission and conduction characteristics of electrical signals due to impedance and transmission loss are required. For this purpose, materials having stable and excellent electrical characteristics (for example, low dielectric constant (ε), low dielectric loss tangent (tan δ), low moisture absorption) in a high frequency region are required. However, polyimide resins have a problem that it is difficult to achieve this.

Therefore, an object of the present invention is to provide a multi-layer substrate which is thinner than the current one capable of coping with next-generation high-speed transmission, and a method of manufacturing the same.

In order to solve the above problems, the multilayer substrate of the present invention is a multilayer substrate in which conductive layers and insulating layers are alternately stacked, and thermoplastic resin and thermosetting insulating resin are alternately used as the insulating layers. It is characterized in that it has a multilayer structure in which layers are sequentially laminated.

Further, the conductor layers are formed on both sides of a plurality of the thermoplastic resins, a plurality of two-layer substrates are formed, and the thermosetting insulating resin is laminated as a bonding layer between the plurality of two-layer substrates. The above multilayer structure may be created.

In addition, a liquid crystal polymer may be used as the thermoplastic resin.

In addition, the multilayer structure may be stacked by a bump build-up method without performing a plating process.

In order to solve the said subject, the multilayer printed wiring board of this invention is characterized by having the said multilayer structure.

In order to solve the said subject, the multilayer flexible wiring board of this invention is characterized by having the said multilayer structure.

In order to solve the above-mentioned subject, a multilayer rigid flexible wiring board of the present invention is characterized by having the above-mentioned multilayer structure.

In addition, an opening may be provided in the multilayer rigid flexible wiring board, a cover lay of polyimide or liquid crystal polymer may be provided in the opening, and a flexible structure having a plurality of the conductor layers may be formed.

In order to solve the above-mentioned subject, a manufacturing method of a multilayer board of the present invention is a manufacturing method of a multilayer board which laminates an electric conduction layer and an insulating layer by turns, and thermoplastics as thermosetting resin and thermosetting. It is characterized in that the conductive insulating resin is alternately laminated sequentially.

Further, the conductor layers are formed on both sides of a plurality of the thermoplastic resins, a plurality of two-layer substrates are formed, and the thermosetting insulating resin is laminated as a bonding layer between the plurality of two-layer substrates. The multilayer substrate may be formed.

Alternatively, an opening may be provided in the multilayer substrate, a cover lay of polyimide or liquid crystal polymer may be provided in the opening, and a flexible structure having a plurality of the conductor layers may be formed.

According to the present invention, high speed transmission can be coped with by using a material having stable and excellent electric characteristics (for example, low dielectric constant (ε), low dielectric loss tangent (tan δ), low moisture absorption) in a high frequency region, In addition, by laminating these materials by a build-up method, it is possible to provide a multilayer substrate thinner than currently and a method for manufacturing the same.

It is a conceptual diagram of the manufacturing method of the multilayer substrate of this invention. It is a conceptual diagram of the manufacturing method of the multilayer substrate of this invention. It is a conceptual diagram of the manufacturing method of the multilayer substrate of this invention. It is a conceptual diagram of the manufacturing method of the multilayer substrate of this invention. It is a schematic diagram of a rigid flexible wiring board of 10 layers as one embodiment of a multilayer board of the present invention. It is a figure explaining one Embodiment of the manufacturing method of the multilayer substrate of this invention. It is a figure explaining one Embodiment of the manufacturing method of the multilayer substrate of this invention. It is a figure explaining one Embodiment of the manufacturing method of the multilayer substrate of this invention. It is a figure explaining one Embodiment of the manufacturing method of the multilayer substrate of this invention. It is a figure explaining one Embodiment of the manufacturing method of the multilayer substrate of this invention. It is a figure explaining one Embodiment of the manufacturing method of the multilayer substrate of this invention. It is a figure explaining one Embodiment of the manufacturing method of the multilayer substrate of this invention. It is a figure explaining one Embodiment of the manufacturing method of the multilayer substrate of this invention.

Embodiments of the present invention will be described with reference to the drawings.

1 to 4 are conceptual views of an example of a method of manufacturing a multilayer substrate according to the present invention.

In FIG. 1, first, bumps 103 are printed on the conductor 102 to form a wiring pattern connecting two wiring layers in the internal circuit.

There are two structures called through holes and vias as structures for interconnecting wiring patterns in desired layers of a substrate having two or more wiring layers. The two are not essentially different, and in general, a connection through a hole penetrating the entire substrate is called a through hole, and a structure connecting through a layer between multilayer plates is called a via. Therefore, the bumps are also a kind of vias, and in this case, they are called bumps in the manufacturing process and are called vias after manufacturing. Further, in FIG. 1, an Ag-based conductive resin is generally used as the bump 103, and copper is generally used as the conductor 102, but the invention is not limited thereto.

Next, in FIG. 1, the thermoplastic resin 101 and the other conductor 102 are simultaneously laminated on the printed conductor of the bump 103 on the above-mentioned conductor 102 to create a prototype (not shown) of a double-sided board. Do.

Although a liquid crystal polymer (LCP: Liquid Crystal Polymer (CTZ: manufactured by Kuraray Co., Ltd.)) is used as the thermoplastic resin 101, the invention is not limited thereto. In order to support high-speed transmission, excellent transmission characteristics of high frequency signals, stable low reactance, excellent transmission and conduction characteristics of electrical signals due to impedance and transmission loss are required. For this purpose, materials having stable and excellent electrical characteristics (for example, low dielectric constant (ε), low dielectric loss tangent (tan δ), low moisture absorption) in a high frequency region are required. Therefore, the thermoplastic resin 101 is not limited to the above-mentioned materials as long as it satisfies such characteristics.

In FIG. 1, one of the conductors 102 indicated by the one-dot-and-dash line of the above-mentioned double-sided substrate prototype is etched to form a circuit pattern 102 ', and a two-layer basic lamination unit 100 is produced. Note that the conductor 102 on the inner side when being laminated is etched before being laminated, and the conductor 102 on the outer side when being laminated is etched after being laminated. The same applies to the following steps.

Next, in FIG. 1, the same process as the lamination unit 100 is performed to form another lamination unit (not shown), and then the bumps 103 are printed on the circuit pattern 102 ′ on the etched surface to laminate two layers. Create a unit 110.

Next, a thermosetting resin 104 is sandwiched between the lamination unit 100 and the lamination unit 110 as an adhesive layer to form a lamination unit of four layers. Although a thermosetting insulating resin film for bonding (ADFLEMA (registered trademark): made by Namix Co., Ltd.) is used as the thermosetting resin 104, a thermosetting resin having characteristics of low dielectric constant, low dielectric loss tangent, and low moisture absorption Other resins can also be used as long as they are resinous.

In FIG. 2, the conductor 102 on the inner side is etched when laminating the four-layered lamination unit created by laminating the lamination unit 100 and the lamination unit 110, to form a circuit pattern 102 ', and four layers are formed. The lamination unit 220 of

Next, the same process as the stacking unit 110 is performed to create another two-layer stacking unit 230 having different circuit patterns. Subsequently, the thermosetting resin 104 is laminated as an adhesive layer between the four-layer stacking unit 220 and the two-layer stacking unit 230 to form a six-layer stacking unit.

In FIG. 3, the conductor 102 on the inner surface is etched when laminating a six-layered lamination unit made by laminating four-layered lamination units 220 and two-layered lamination units 230, and a circuit pattern 102 '. To form a six-layer stacked unit 340.

Next, in FIG. 3, the same process as the four-layer stacking unit 220 is performed to create another four-layer stacking unit having a different circuit pattern, and the circuit pattern 102 'on the inner surface when stacking is performed. The bumps 103 are printed on the substrate to make a lamination unit 350.

In FIG. 4, a thermosetting resin 104 is sandwiched and laminated as an adhesive layer between a six-layer lamination unit 340 and a four-layer lamination unit 350 to form a ten-layer lamination unit 460.

After that, the first and tenth layers of the conductor 102, which became the outermost surface, are etched to form a circuit pattern 102 ', and finally, a surface is coated with a cover, plating, etc. The manufacture of the laminated substrate is completed.

In addition, the order of lamination is not limited to this example, and two, four, and four layers of lamination units are prepared, and two and eight layers of lamination units may be simultaneously laminated. Each of the layers may be prepared and laminated, or two layers may be sequentially laminated, and the invention is not limited to these examples.

As described above, by forming the laminated substrate by the bump build-up method, the plating step necessary for the method such as the laser via and the through hole becomes unnecessary, so that a thin multilayer substrate without a plating layer can be formed. .

In addition, since the thermosetting resin has a glass transition temperature higher than the lamination pressing temperature, the use of the thermosetting resin makes it possible to reduce the damage due to the heat history due to the repetition of lamination (sequential lamination), and Even if it is made thinner, the reliability can be kept high, and therefore, thinning of the multilayer substrate by the build-up method can be achieved.

Also, since thermosetting resins generally have low flame retardancy, it is difficult to satisfy the standards of flame retardancy such as UL (Underwriters Laboratories) if the insulating layer is composed only of thermosetting resins, but the flame retardancy is low. By alternately laminating not only a low thermosetting resin but also a highly flame retardant thermoplastic resin, it is possible to satisfy the flame retardancy standard such as UL.

Also, since both the thermoplastic resin 101 and the thermosetting resin 104 have stable and excellent electric characteristics (for example, low dielectric constant, low dielectric loss tangent, low moisture absorption) in a high frequency region, the next generation high speed transmission Can also respond.

FIG. 5 is a schematic view of a 10-layer rigid flexible wiring board 500 as an embodiment of the multilayer board of the present invention.

In FIG. 5, a ten-layer rigid flexible wiring board 500 includes a ten-layer conductor 502 of conductive layers LY1 to LY10 and a thermoplastic resin 501 laminated between conductors 502 such as adjacent conductive layers LY1 and LY2. A thermosetting resin 504 laminated between the adjacent conductive layers LY2, LY3 and the like, and a via 503 connecting the conductors are provided. The thermoplastic resin 501 and the thermosetting resin 504 are alternately stacked between the conductors 502. Here, a liquid crystal polymer is used as the thermoplastic resin 501, but is not limited thereto. Moreover, although the thermosetting insulating resin film for adhesion | attachment is used as the thermosetting resin 504, it is not limited to this.

In the rigid flexible wiring board 500, openings 506 and 507 are formed in the conductor 502 (conductive layers LY1 to LY3) and the conductor 502 (conductive layers LY8 to LY10). The thermoplastic resin 501 is exposed as a cover lay 508 on the surface of the openings 506 and 507, and a flexible wiring portion 509 is formed. Further, a cover coat 505 is stacked on the surface of the conductor 502 (conductive layers LY1 and LY10) other than the opening, and a rigid wiring portion 510 is formed. The cover lay 508 is a soft film for protecting the surface of the flexible printed wiring portion 509. Here, the thermoplastic resin 501 exposed on the surface of the openings 506 and 507 or the opening 506, Polyimide or the like attached to 507 later is used. The thermosetting resin 504 can not generally be used as the coverlay 508 because the flame retardancy is low.

As described above, in the multilayer substrate of the present invention, since the rigid wiring portion and the flexible wiring portion of the rigid flexible wiring board can be freely formed, the degree of freedom in design is enhanced. For this reason, the multilayer board of the present invention can be used also as a rigid wiring board or a flexible wiring board by selecting the above-mentioned production method. In addition, the number of layers can be changed because the build-up method using bumps is used.

6 to 10 are views for explaining one embodiment of a method of manufacturing a multilayer substrate according to the present invention.

In FIG. 6, first, conductors 602 (conductive layers LY3 and LY4) are formed on both sides of a thermoplastic resin 601 to form a stacked unit 600. Bumps 603 are printed inside the thermoplastic resin 601 to form a wiring pattern for connecting two wiring layers (conductive layers LY 3, LY 4, etc.). The bump printing process is performed in the same manner as the processes shown in FIGS. 1 to 4. In addition, the conductor 602 on the inner side during lamination is etched before lamination, and the conductor 602 on the outer side during lamination is etched after lamination, but here the description will be described. I omit it.

Next, the conductors 602 (conductive layers LY5 and LY6) are formed on both surfaces of the thermoplastic resin 601, and the bumps 603 are printed on the surface on the conductor 602 (conductive layer LY5) side to form a stacked unit 610.

In FIG. 7A, conductors 602 (conductive layers LY1 and LY2) are formed on both sides of a thermoplastic resin 601, and a thermosetting resin 604 for bonding is disposed on the surface of the conductor 602 (conductive layer LY2). Create

7A, when it is desired to form a flexible wiring portion 609 described later, an opening is provided in the thermosetting resin 604, and a polyimide film or the like is disposed as the spacer 605 in the opening so that peeling can be performed after lamination. Keep it. Here, an opening is provided in the thermosetting resin 604, the conductor 602 (conductive layer LY2), and the conductor 602 (conductive layer LY3) shown in FIG. 7B described later.

Next, in FIG. 7B, the above-mentioned lamination unit 600, 610 is sandwiched between the thermosetting resin 604 for adhesion and laminated, and the bump 603 is printed on the surface on the side of the conductor 602 (conductive layer LY3). Create

Similarly, in FIG. 7C, the conductor 602 (conductive layers LY7 and LY8) is formed on both sides of the thermoplastic resin 601, and the bumps 603 are printed on the surface on the conductor 602 (conductive layer LY8) side to create a stacked unit 740. Do.

Next, in FIG. 7D, conductors 602 (conductive layers LY9 and LY10) are formed on both sides of the thermoplastic resin 601, and a thermosetting resin 604 for bonding is disposed on the surface of the conductor 602 (conductive layer LY9), The lamination unit 750 is created. As described above, when it is desired to form the flexible wiring portion 609, an opening is provided in the thermosetting resin 604 so that the surface of the thermoplastic resin 601 is exposed, and a polyimide film or the like is disposed as the spacer 605 in the opening. And allow them to peel off after lamination. Here, an opening is provided in the thermosetting resin 604, the conductor 602 (conductive layer LY9), and the conductor 602 (conductor layer LY8) illustrated in FIG. 7C described above.

In FIG. 8, the lamination unit 720 and the lamination unit 730 are laminated to form a lamination unit 860. Similarly, the lamination unit 740 and the lamination unit 750 are laminated, and the bumps 603 are printed on the surface of the conductor 602 (conductive layer LY7) to form a lamination unit 870.

In FIG. 9, the lamination unit 860 and the lamination unit 870 are laminated with the thermosetting resin 604 for bonding interposed therebetween, to form a 10-layer lamination unit 980. In the case where the flexible wiring portion 609 is provided, the flexible opening is slitted before outer shape processing so that lid removal can be performed.

In FIG. 10, finally, a cover coat and plating treatment are performed, and then lid removal is performed to expose the flexible wiring portion 609, and a rigid flexible wiring board 1090 of 10 layers is completed. A thermoplastic resin 601, polyimide, or the like can be used as the cover lay 608 on the surface of the flexible wiring portion 609. Further, portions other than the flexible wiring portion 609 become the rigid wiring portion 610.

As described above, according to the present invention, high speed transmission can be supported by using a material having stable and excellent electric characteristics (for example, low dielectric constant, low dielectric loss tangent, low moisture absorption) in a high frequency region, and By laminating these materials by the build-up method, it is possible to provide a thinner multilayer substrate and a method of manufacturing the same.

100, 110, 220, 230, 340, 350, 460, 600, 610, 720, 730, 740, 750, 860, 870, 980 Laminated unit 101, 501, 601 Thermoplastic resin 102, 502, 602 Conductor 103, 503 , 603 bumps (vias)
104, 504, 604 thermosetting resin 500, 1090 laminated substrate 505 cover coat 506, 507 opening 508, 608 cover lay 509, 609 flexible wiring portion 510, 610 rigid wiring portion 605 spacer

Claims (11)

1. A multilayer substrate in which conductive layers and insulating layers are alternately stacked,
   A multilayer substrate having a multilayer structure in which a thermoplastic resin and a thermosetting insulating resin are alternately and sequentially laminated as the insulating layer.
2. The conductor layer is formed on both sides of a plurality of the thermoplastic resins, a plurality of two-layer substrates are formed, and the thermosetting insulating resin is laminated between the plurality of two-layer substrates as an adhesive layer, thereby forming the multilayer The multilayer substrate according to claim 1, wherein a structure is created.
3. The multilayer substrate according to claim 1, wherein a liquid crystal polymer is used as the thermoplastic resin.
4. The multilayer substrate according to claim 1, wherein the multilayer structure is stacked by a bump build-up method without performing a plating process.
5. The multilayer printed wiring board which has a multilayer structure in any one of the said Claims 1 thru | or 4.
6. The multilayer flexible wiring board which has a multilayer structure in any one of the said Claims 1 thru | or 4.
7. The multilayer rigid flexible wiring board which has a multilayer structure in any one of the said Claim 1 thru | or 4.
8. The multilayer rigid body according to claim 7, characterized in that an opening is provided in the multilayer rigid flexible wiring board, a cover lay of polyimide or liquid crystal polymer is provided in the opening, and a flexible structure having a plurality of the conductor layers is formed. Flexible wiring board.
9. A method of manufacturing a multilayer substrate in which conductive layers and insulating layers are alternately stacked,
   A manufacturing method of a multilayer substrate comprising laminating alternately a thermoplastic resin and a thermosetting insulating resin as said insulating layer.
10. The conductor layer is formed on both sides of a plurality of the thermoplastic resins, a plurality of two-layer substrates are formed, and the thermosetting insulating resin is laminated between the plurality of two-layer substrates as an adhesive layer, thereby forming the multilayer The method of manufacturing a multilayer substrate according to claim 9, wherein the substrate is formed.
11. The method for manufacturing a multilayer substrate according to claim 9, characterized in that an opening is provided in the multilayer substrate, a cover lay of polyimide or liquid crystal polymer is provided in the opening, and a flexible structure having a plurality of the conductor layers is formed. .

Images