JP2003234579A - Method of manufacturing multilayer printed wiring board with chip type resistor built therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer printed wiring board having a chip-type resistor built therein which has a stable resistance value with little changes with the passage of time, without adjustments to the resistance value by trimming or the like. <P>SOLUTION: The method of manufacturing the multilayer printed wiring board comprises the processes of mounting the chip type resistor on an inner layer substrate, with a support body on the upper side and a resistor on the land side; stacking an interlayer insulation layer on the inner layer substrate; polishing the laminate; and forming a conductor layer on the polished laminate via an insulation layer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer printed wiring board having a resistor as an inner layer.

[0002]

2. Description of the Related Art In portable information terminal equipment,
As the density has increased, the number of components mounted on printed wiring boards has continued to increase.
Since it is required to be thin, it is no longer possible to deal with it only by mounting the components on the surface of the printed wiring board.

As a method of avoiding such a situation, there is already known a method of forming a resistor inside a multilayer printed wiring board by a printing method, a vapor deposition method or the like. However, the formed resistor requires trimming adjustment so as to have a predetermined resistance value, which is very troublesome. Further, even if the initial resistance value can be set within a certain range by trimming, there is a problem that the resistance value is difficult to stabilize due to a change with time.

Therefore, in order to form a resistor having a stable resistance value, a method of mounting a chip-type resistor standardized as a product inside a multilayer printed wiring board can be considered. However, when the interlayer insulating layer is formed and provided with a storage area that is substantially equal to that of the component after the component is mounted, a load is applied to the component during stacking, which causes a problem that the component is cracked.

Further, a multilayer printed wiring board used for portable terminal equipment is required to be small and thin, the thickness of the insulating layer is about several tens of μm, and the thickness of parts is several hundreds of μm.
It was impossible to embed the chip-type resistor in (1) inside the multilayer printed wiring board.

[0006]

Therefore, the inventor of the present invention
The present invention has been completed by focusing attention on the structure of the chip-type resistor in which the resistor is formed on a support such as ceramics that occupies most of the thickness.

An object of the present invention is to provide a multi-layer printed wiring board having a built-in resistor having a stable resistance value with little change over time, without adjusting the resistance value by trimming or the like.

[0008]

According to the present invention, a chip-type resistor is mounted on an inner layer substrate with its support positioned on the upper side and the resistor being the land side; and the inner layer after the mounting. A step of laminating an interlayer insulating layer on the substrate; a step of polishing the laminated plate after the laminating; a step of interposing an insulating layer on the laminated plate after the polishing to form a conductor layer. The above object is achieved by a method of manufacturing a multilayer printed wiring board incorporating a chip-type resistor.

Further, according to the present invention, in particular, regarding the interlayer insulating layer, the portion where the chip type resistor is mounted is opened, and the height of the interlayer insulating layer is made higher than that of the mounted chip type resistor. The above object is achieved. With such a configuration, the pressure of the press in the laminating process does not directly act on the chip resistor, and the mounted chip resistor is not cracked.

Further, according to the present invention, in particular, regarding the lamination of the interlayer insulating layer, at least two or more insulating layers having different color tones having an opening portion provided in a component mounting portion are laminated, and the interlayer insulating layer and the opening portion are laminated. The above-mentioned object is achieved by further laminating an insulating layer covering the above.

In addition, the present invention achieves the above object by laminating the above-mentioned interlayer insulating layer and polishing and thinning the chip type resistor mounted even to the interface of the interlayer insulating layers having different color tones. .

The total thickness of the printed wiring board is reduced by laminating interlayer insulating layers having different tones and polishing until the thickness including the chip resistor mounted up to the interface of the insulating layers having different tones becomes thin. Further, by using the interlayer insulating layer having different color tones, the polishing thickness can be processed with high accuracy.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. 1A and 1B are cross-sectional views illustrating a mounting structure of a chip-type resistor, where FIG. 1A shows a conventional mounting structure and FIG. 1B shows a mounting structure according to the present invention.

The chip resistor 4 is formed so as to connect the support 15 made of a ceramic base material, the conductors 16 formed on the support 15 with a space therebetween, and the conductors 16 separated from each other. It is composed of a resistor 5, a protective layer 18 for protecting the resistor 5, and a side electrode 17 formed on the side surface. Usually, as shown in FIG. On the land side, the mounting land 2a, the side surface electrode 17, and the solder 6 were connected to each other to mount the chip resistor 4.

According to the present invention, as shown in FIG. 1 (b), the chip resistor 4 is reversely mounted to the usual mounting structure.
5 is positioned on the upper side, the resistor 5 is mounted on the land side, and then the support 15 is polished and thinned to make the chip resistor 4 thinner. Is easily incorporated in a multilayer printed wiring board.

Further, after the chip-type resistor 4 is mounted, when the interlayer insulating layer having the opening provided in the component mounting portion is laminated, the height of the interlayer insulating layer is higher than that of the mounted chip-type resistor 4. , Directly chip-type resistor 4 when crimping with laminated press
Since no pressure is applied to the chip-type resistor 4, the mounted chip-type resistor 4 is not damaged, which is effective.

Further, after mounting the chip-type resistor, two or more interlayer insulating layers having different color tones, each having an opening at the component mounting portion, are laminated, and then the whole is covered with an insulating layer to be laminated to form an insulating layer having a different color tone. It is effective to reduce the thickness and make the thickness uniform by polishing the mounted components up to the layer interface.

FIG. 2 shows an embodiment of the present invention. First, as shown in FIG. 2A, the inner layer substrate 1 in which the wiring circuits 2 and the mounting lands 2a are formed on the front and back surfaces of the insulating layer 1a is obtained by a conventional method such as a subtractive method. Examples of the insulating layer 1a include glass woven cloth or non-woven cloth impregnated with epoxy resin, polyimide resin, BT (bismaleimide-triazine) resin, olefin resin, and the like. As the wiring circuit 2 and the mounting land 2a, Common metals such as copper are preferred. Next, after forming the solder resist 3 having a desired pattern excluding the mounting lands 2a, a solder paste is printed on the mounting lands 2a. Next, as shown in FIG. 1B, the chip type resistor 4 is arranged on the mounting land 2a in the direction opposite to the normal direction, that is, the support 15 is positioned on the upper side and the resistor 5 is arranged on the land side. After that, the mounting land 2a and the side surface electrode 17 of the chip type resistor 4 are soldered by a reflow process.
Connect with. As a result, the chip-type resistor 4 shown in FIG.
The inner layer board 1 having the both surfaces mounted is obtained.

Next, on both surfaces of the inner layer substrate 1 of FIG.
The interlayer insulating layer 7 having a three-layer structure of 7a, 7b, and 7c is shown in FIG.
Arrange as shown in (b). The interlayer insulating layer 7a is a layer having a thickness that serves as an index when the chip type resistor 4 is thinned later, and has an opening 8 at a position corresponding to the position of the chip type resistor 4. . The interlayer insulating layer 7b is a layer having a color tone different from that of the interlayer insulating layer 7a and having a function of indicating a polishable region, and has an opening 8 similar to that of the interlayer insulating layer 7a. The interlayer insulating layer 7c has a different color tone from the interlayer insulating layer 7b (may be the same color as the interlayer insulating layer 7a), fills the gap formed by the formation of the opening 8, and stacks the interlayer insulating layers 7a to 7c. The thickness is such that the chip-type resistor 4 is buried in the case.
By surely filling the chip resistor 4 with the interlayer insulating layer,
Since the pressure at the time of stacking is not directly applied to the chip type resistor 4, the chip type resistor 4 is not damaged and the yield is improved. The reason why the color tone of the insulating layer 7c is different from that of the insulating layer 7b is that when the resin of the interlayer insulating layer 7c slightly flows into the opening of the insulating layer 7a when the interlayer insulating layers are laminated, This is because if the insulating layers 7c and 7b have the same color, the boundary line of the polishable region becomes unclear. The types of the interlayer insulating layers 7a to 7c include the insulating layer 1a of the inner layer substrate 1.
The interlayer insulating layer 7a may be formed in the opening 8
Since it is necessary to bury it with resin, a B-stage (semi-cured state) is used, and the interlayer insulating layer 7b is
C so that the resin of the interlayer insulating layer 7b does not enter the opening of a.
Interstage insulating layer 7c using the stage (hardened)
The same material as the interlayer insulating layer 7a can be used. The openings 8 in the interlayer insulating layers 7a and 7b can be formed by punching with a die, NC drill, laser processing, or the like. The above-mentioned interlayer insulating layers 7a to 7c are laminated and pressed by the press plate 9 to obtain a laminated plate in the state of FIG. 2 (c).

Next, the laminated plate of FIG. 2 (c) is polished by means such as buff polishing, flat surface polishing, machining center and belt polishing until the layer of the interlayer insulating layer 7a is exposed.
As a result, a laminated plate in the state of FIG. 2D is obtained in which the chip type resistor 4 is formed in parallel with the interlayer insulating layer 7 (a) thinned by polishing and polished to a desired thickness.

Next, the second insulating layer 1 is formed on the laminated plate of FIG.
0 and the conductor foil 11 or both are laminated with a resin-coated copper foil laminated in advance to obtain the laminated body of FIG. Next, a circuit is formed on the conductor foil 11,
By repeating the steps from (a) to FIG. 2 (e),
A multilayer printed wiring board 12 having a built-in chip type resistor 4 as shown in FIG. 2 (f) is obtained. For the conduction between the front and back sides and the conduction between each layer, a through-hole is provided, and each layer is IV
H and BVH may be connected to obtain conduction in each layer (not shown).

According to such an embodiment of the present invention, by making the thickness of the interlayer insulating layer 7 higher than that of the mounted chip type resistor, the pressing pressure at the time of lamination is directly applied to the chip type resistor. In addition, since the interlayer insulating layer having a different color tone is provided as the polishing region, the chip resistor 4 can be accurately thinned without being damaged.

[0023]

According to the present invention, it is possible to obtain a multilayer printed wiring board having a built-in chip-type resistor having a stable resistance value with little change over time without adjusting the resistance value by trimming or the like. .

[Brief description of drawings]

FIG. 1 is a schematic sectional view for explaining a mounting structure of a chip resistor.

FIG. 2 is a schematic cross-sectional process diagram for explaining the embodiment of the invention.

[Explanation of symbols]

1: Inner layer substrate 2: Wiring circuit 3: Solder resist 4: Chip type resistor 5: resistor 6: Solder 7: Interlayer insulation layer 7a, 7b, 7c: interlayer insulating layer 8: opening 9: Press plate 10: Second insulating layer 11: Conductor foil 12: Multilayer printed wiring board

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Claims (4)

[Claims] 1. A step of mounting a chip-type resistor on an inner layer substrate with its support positioned on the upper side and making the resistor on the land side; laminating an interlayer insulating layer on the inner layer substrate after the mounting. A step of polishing the laminated plate after the lamination; and a step of forming a conductor layer by interposing an insulating layer on the laminated plate after the polishing, Manufacturing method of printed wiring board. 2. The interlayer insulating layer according to claim 1, wherein a portion where the chip type resistor is mounted is opened, and the height of the interlayer insulating layer is higher than that of the mounted chip type resistor. Item 10. A method for manufacturing a multilayer printed wiring board incorporating the chip-type resistor according to Item 1. 3. The lamination of the above-mentioned interlayer insulating layer comprises laminating at least two or more insulating layers having different color tones each having an opening in a component mounting portion and covering the interlayer insulating layer and the opening. The method for manufacturing a multilayer printed wiring board having a built-in chip-type resistor according to claim 2, further comprising stacking layers. 4. The chip-type resistor according to claim 3, wherein the chip-type resistor including the chip-type resistor mounted up to the interface of the interlayer insulating layers having different color tones is polished and thinned. Manufacturing method of printed wiring board.