JPH05283866A - Multilayer circuit board containing printed polymer resistor - Google Patents

Abstract

PURPOSE:To reduce a resistance change of a printed polymer resistor by forming the resistor on a base circuit board made of dielectric such as epoxy, polyimide, ceramic, etc., sequentially forming an insulating layer of photosensitive resin material and a conductor layer thereon, and further laminating many wirings thereon. CONSTITUTION:A wiring pattern 11 is formed on a base circuit board 3 formed of a double-sided copper-clad glass epoxy board, then Ag electrodes 12 are printed, dried and semi-cured. Then, carbon.resin series polymer resistor 1 is printed, and heated simultaneously with the electrodes 12 to completely cure. It is coated with photosensitive epoxy resin, exposed to form an insulating layer 2, and simultaneously formed with a recess for a photoviahole 5. A copper foil is formed on the entire insulating layer by electroplating to form the wiring pattern 11. A multilayer wring layer is formed, coated with photosensitive solder resist, and cured. Since heat to be applied to the resistor 1 is small, the resistance change of the resistor 1 can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer wiring board, and more particularly to a multilayer wiring board containing a polymer printing resistor suitable for downsizing electronic devices.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 61-7696 discloses that a multilayer press system (laminate system) is used to form multiple layers, and a polymer printed resistor is provided on an inner wiring layer to form a multilayer wiring board. There is. Further, JP-A-2-241080 discloses that an undercoat is applied to a wiring board, a polymer printing resistor is printed and formed, and an overcoat is applied thereon. ..

[0003]

The conventional polymer printing resistor provided in the multilayer substrate by the laminated pressing method has a problem that the temperature drift of the resistance value due to heat generation is large. Further, even if the resistance value is adjusted by trimming, there is a problem in that the resistance value changes due to the pressurizing and heating steps of the lamination press. For this reason, it was difficult to incorporate the polymer printing resistor in the inner wiring layer of the multilayer wiring board.

FIG. 4 is a partial sectional view of a wiring board including a polymer-printed resistor manufactured by the above-mentioned conventional technique. An undercoat 1 is placed on a wiring board 6 provided with a wiring pattern 11.
3, Ag electrode 12, polymer printing resistor 1, overcoat
To be manufactured by sequentially printing and curing. Since the above-mentioned substrate has a relatively large number of manufacturing steps, it is difficult to reduce the manufacturing cost, and since the wiring board 6 is not flat, the printability of the polymer printing resistor 1 is poor, so that the printing stain, the printing blurring, etc. are likely to occur.

[0005]

In order to solve the above problems, a polymer printed resistor is formed on a base wiring board made of a dielectric material such as epoxy, polyimide or ceramic, and a photosensitive resin material is formed thereon. The insulating layer and the conductor layer are sequentially formed, and a multilayer wiring portion including the same insulating layer and the conductor layer is further laminated thereon. Further, as the above-mentioned base wiring board, a metal board having good thermal conductivity and coated with an insulating layer such as a photosensitive epoxy resin or a photosensitive polyimide resin and cured is used.

Insulating undercoat layers and overcoat layers are not provided on both sides of the polymer printing resistor. Further, a plating resist layer is provided on the surface of the printed wiring board on which the polymer printed resistance is printed, and a pattern is formed by electroless plating so that the thickness is equal to that of the plating resist. And above the polymer
Print the print resistor.

[0007]

The polymer printed resistor of the present invention is formed on each of the above-mentioned base wiring boards, and the insulating layer and the conductor layer are formed in multiple layers on the upper part thereof. That is, the polymer printing resistor is formed at a position farthest from the multilayer wiring layer. In addition, the base wiring board, which is obtained by insulatingly coating the metal plate, absorbs the heat acting on the polymer printing resistor provided directly on the surface thereof and suppresses the temperature change. A plating resist layer having the same thickness as the conductor wiring pattern of the base wiring board flattens the printed surface of the polymer printing resistor.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a manufacturing process diagram of a multilayer wiring board according to the present invention. In step S1, an etching resist is applied to the base wiring board 3 using a double-sided copper-clad glass epoxy substrate to form a wiring pattern 11, and then in step S2, the Ag electrode 12 is screen-printed. Print, dry and semi-cure. Then, in step S3, a carbon / resin-based polymer printing resistor 1 is printed by a screen printing method to form Ag.
The electrode 12 and the electrode 12 are heated together and completely cured. In addition, A
It is also possible to print and cure the polymer printing resistor 1 after printing and curing the g-electrode 12.

Next, in step S4, a photosensitive epoxy resin is applied and exposed to form an insulating layer 2, and at the same time, photovi
A recess for the a hole 5 is formed. Then, in step S5, the surface of the insulating layer 2 is roughened to activate the surface to increase the adhesion strength with the copper foil, and then in step S6, a copper foil is formed on the entire surface of the insulating layer by electrolytic plating, and an etching resist is formed. The wiring pattern 11 is formed by applying and etching this. At this time, the wiring in the photo via hole 5 is also formed at the same time. When the wiring pattern 11 is formed by electroless plating, a plating resist is formed after the insulating layer 2 is roughened and activated, and the wiring pattern is formed by electroless plating.
11 is formed.

In step S7, the steps S4 to S6 are repeated to form a multilayer wiring layer. Finally step S
7, a photosensitive solder resist is applied and cured to form a solder resist. In the case of the electroless plating method, the plating resist can be used as a solder resist in combination, so that the above solder resist forming step can be omitted.

Since the multilayer printed circuit board produced by the above process requires less heat than the polymer printing resistor 1 as compared with the conventional laminated pressing method, the change in the resistance value of the polymer printing resistor 1 due to the heating during manufacturing is reduced. Of the polymer printed resistor 1 as shown in FIG.
And the overcoat 14 can be omitted.

Further, since the polymer printed resistor 1 is formed in the inner layer portion of the multilayer wiring board, the mounting area for the polymer printed resistor can be reduced from the surface layer portion of the multilayer wiring board (1
Effective reduced area when converted to 005 chip resistance ≈ 0.
015 cm ² × resistance number). Therefore, by utilizing the increase of the surface layer area, as shown in FIG.
OP / Small Outline Package (IC / LSI8)
The number of electronic components 9 mounted can be increased.

FIG. 3 is a manufacturing process diagram of another multilayer wiring board having a polymer-printed resistor according to the present invention. In a multi-layer wiring board for power amplifier circuits that generate a large amount of heat, if the polymer printing resistor 1 is provided on a metal plate with good thermal conductivity such as copper or aluminum, heat dissipation is improved and maximum allowable power consumption is increased. can do. Comparing FIG. 3 with FIG. 2, the other steps are the same except that the base wiring board 3 in FIG. 2 is a base metal plate (copper plate) 4 provided with an insulating layer 2 on the surface. is there.

Since the through-hole can be easily formed in the multilayer wiring board of FIG. 3, not only the base metal plate 4 can be used as the heat transfer layer but also as the ground layer and the power supply layer. You can If the base metal plate 4 is used as the ground layer, the electromagnetic shield effect can be enhanced.

FIG. 5 is a partial cross-sectional view of a multilayer wiring board having a polymer printed resistor 1 formed by an electroless copper plating method such as an additive method or a part-really additive method. The plating resist 16 is formed on the wiring board 6, and the plating resist 1
A wiring pattern 11 is deposited in the same thickness as 6, and a polymer printing resistor 1 is printed on the wiring pattern 11. Since the surface becomes flat, the printability of the polymer printing resistor 1 is improved, and it is possible to reduce print blur and print blurring.

FIG. 6 is a partial sectional view of a multilayer wiring board in which the printability of the polymer printed resistor 1 is further improved. Ni / Au plating layer 1 on the wiring pattern (copper pattern) 11
5, the surface of the Ni / Au plated layer 15 is aligned with the thickness of the plating resist 16 to completely flatten the printed surface of the polymer printing resistor 1 to further improve the printability.

FIG. 7 is a perspective view of a mobile phone incorporating the multilayer wiring board of the present invention. Reference numeral 18 denotes the metal base multilayer wiring board with a built-in polymer printing resistor, which can improve the heat dissipation and enhance the electromagnetic shield effect, thus downsizing the device and suppressing unnecessary radiation of electromagnetic waves. It is possible to improve resistance to external noise.

[0018]

According to the present invention, since the polymer printing resistor is formed in close contact with the base wiring board, heat generated during the manufacture of the multilayer wiring layer formed thereon is less likely to be transmitted to the polymer printing resistor. , It is possible to reduce the change in the resistance value of the polymer printing resistance. In particular, when a base wiring board in which a metal plate is insulation-coated is used, the change in the resistance value of the polymer printing resistance can be further reduced. Further, since the undercoat and overcoat required for forming the polymer printing resistor on the surface layer of the conventional wiring board can be eliminated,
The manufacturing process can be simplified, and at the same time, the printing surface of the polymer printing resistor can be flattened. In particular, by printing a polymer printing resistor on a plating resist layer having a thickness equal to that of the conductor wiring pattern of the above-mentioned wiring board, the printing surface of the polymer printing resistor is completely flattened to cause printing drip or printing. It is possible to reduce bleeding and improve the printing accuracy. Further, since the polymer printing resistance is formed in the deep portion of the multilayer wiring layer, it is possible to reduce the resistance value variation due to moisture absorption. Furthermore, since the polymer printing resistor is formed on the surface of the base wiring board, the mounting area of electronic parts on the multilayer wiring layer and its surface can be relatively increased. At the same time, since the wiring pattern length of the polymer printing resistor can be shortened, the signal seeding delay time can be reduced and the influence of external noise such as unnecessary radiation or EMI can be reduced.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of a multilayer wiring board according to the present invention.

[FIG. 2] For example, SOP (Small Outline Pa
It is possible to increase the number of mounted IC / LSIs 8 and electronic components 9 that are sealed.

FIG. 3 is a manufacturing process diagram of another polymer-embedded resistor built-in multilayer wiring board according to the present invention.

FIG. 4 is a partial cross-sectional view of a wiring board including a conventional polymer printed resistor.

FIG. 5 is a partial cross-sectional view of a multilayer wiring board on which a polymer printing resistor is formed by an electroless copper plating method such as an additive method or a partly-additive method.

FIG. 6 is a partial cross-sectional view of a multilayer wiring board with improved printability of a polymer print resistor.

FIG. 7 is a perspective view of a mobile phone incorporating the multilayer wiring board of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Polymer printing resistor, 2 ... Insulating layer, 3 ... Base wiring board, 4 ... Base metal plate, 5 ... Photo via hole, 6 ...
Wiring board, 7 ... Multilayer wiring board with built-in polymer printing resistor, 8 ... I
C / LSI, 9 ... Electronic component, 10 ... Through hole, 11
... Wiring pattern (conductor layer), 12 ... Ag electrode, 13 ... Undercoat, 14 ... Overcoat, 15 ... Ni / A
u-plated layer, 16 ... Plating resist, 17 ... Mobile phone, 18 ... Metal base multilayer wiring board with built-in polymer printing resistor

Claims (4)

[Claims] 1. A multi-layer wiring board having a built-in polymer printing resistor, wherein the polymer printing resistor is formed on a base wiring board made of a dielectric material such as epoxy, polyimide or ceramic, and is formed on the polymer printing resistor. A polymer including an insulating layer of a photosensitive resin material and a conductor layer formed on the insulating layer, and further including a multilayer wiring portion formed of the insulating layer and the conductor layer laminated on the conductor layer. -Multilayer wiring board with built-in printing resistors. 2. A multilayer wiring board with a built-in polymer printing resistor, which is formed by applying and curing an insulating layer such as a photosensitive epoxy resin or a photosensitive polyimide resin on the surface of a metal plate having good thermal conductivity. And a polymer printed resistor formed on the base wiring board, an insulating layer of a photosensitive resin material formed on the polymer printed resistor, and a conductor layer formed on the insulating layer. A multi-layer wiring board with a built-in polymer printing resistor, comprising a multi-layer wiring section comprising the insulating layer and the conductor layer laminated on the conductor layer. 3. The polymer printing resistor according to claim 1, wherein the polymer printing resistor is not provided with an insulating undercoat layer and an overcoat layer on both sides thereof. Multi-layer wiring board with built-in polymer printing resistors. 4. The polymer printed resistance printed surface of the base wiring board according to claim 1 or 2, wherein a pattern is formed by an electroless plating method so as to have a thickness equal to that of a plating resist and smoothed. , A polymer printed resistor built-in multilayer wiring board having improved printability of the polymer printed resistor.