JP4661351B2 - Passive element built-in wiring board and manufacturing method thereof - Google Patents

Description

  The present invention relates to a multilayer wiring board, and more particularly to a wiring board with a built-in passive element including a passive element such as a resistance element and a capacitor, and a manufacturing method thereof.

  Along with miniaturization and high-density mounting of electronic devices, miniaturization, weight reduction, and high-density wiring of wiring boards used therefor are progressing. Along with this, a resistance built-in wiring board that is formed on the inner layer of a wiring board using a resistance element that has been conventionally surface-mounted as a printed resistor is being developed. As a result, the mounting area of the resistance element is reduced, and high-density wiring is possible. Patent Document 1 describes that a multilayer wiring board is formed by multilayering by a laminated press method (laminate method) and providing a printed resistor on an inner wiring layer. The wiring board forms a wiring circuit in which a wiring layer composed of a conductor circuit pattern and an insulating layer are laminated in that order and energized through the conductor layer penetrating the insulating layer. In the case of a layer structure composed of a plurality of conductor layers, it is a multilayer wiring board, and a case where a wiring layer having a conductive circuit pattern, a passive element such as a resistance element and a capacitor is used for the layer structure is defined as a passive element built-in wiring board.

  The prior art will be described with reference to the drawings. FIG. 4 is a sectional side view of a conventional resistance built-in wiring board. In this figure, a conductor circuit pattern 1 is formed on a wiring board 2 serving as a base, and the conductor circuit pattern 1 at both ends is wired by a resistor 3 through a resistance silver electrode 10 to form a circuit. It is. The surface of the circuit portion is protected with an insulating layer 9.

  As can be seen from FIG. 4, the connection point between the resistor 3 and the conductor circuit pattern 1 exists not only on the end face of the conductor circuit pattern but also on the resistance silver electrode 10 and the conductor circuit pattern. For this reason, it is difficult to predict the electric field inside the resistor, it is difficult to design a shape of the resistor that matches a preset resistance value, and resistance value variations are likely to occur after the resistor element is formed. is there. Moreover, since the cross-sectional shape of the resistance paste after printing is not a square but a rounded shape, it is difficult to control the thickness. For this reason, it is difficult to design the shape of the resistor, and there is a problem that resistance value variations after the formation are likely to occur.

  In addition, even in the dielectric layer of the built-in capacitor, where the dielectric paste is formed by screen printing, the cross-sectional shape of the dielectric paste after printing is not a square but a rounded shape, making it difficult to control the thickness. It is difficult to design a dielectric shape with a preset capacitance. At the same time, there is a problem that capacitance variation after formation is likely to occur (see Patent Document 2).

The known literature is described below.
JP-A 61-7696 JP-A-7-307542

An object of the present invention is to eliminate the above-described conventional problems, and it is possible to easily design a resistor shape in accordance with a set resistance value, and to set a resistance element with small variation in resistance value after formation. It is an object of the present invention to provide a passive element built-in wiring board having a capacitor in which the dielectric shape can be easily designed in accordance with the capacitance value and the capacitance value variation after formation is small, and a method for manufacturing the same.

The invention according to claim 1 of the present invention includes an insulating layer, a conductor circuit pattern provided on the insulating layer, a resistance element electrode that is a part of the conductor circuit pattern, and a resistor that connects between the resistance element electrodes In the passive element built-in wiring board having the resistance element, the resistor and the resistor element electrode are connected only at their end faces, the resistor is thicker than the resistor element electrode, and the resistor is flattened. A passive element built-in wiring board having an upper surface .

  According to a second aspect of the present invention, the conductor circuit pattern further includes a capacitor first electrode as a part thereof, a dielectric formed on the capacitor first electrode, and a capacitor first electrode on the dielectric. The passive element built-in wiring board according to claim 1, comprising two electrodes.

According to a third aspect of the present invention, there is provided an insulating layer, a conductor circuit pattern provided on the insulating layer, a resistor element electrode that is a part of the conductor circuit pattern, and a resistor that connects between the resistor element electrodes In the manufacturing method of the passive element built-in wiring board having the resistance element, the resistive element is formed by at least the following steps.
(A) A step of forming a resist layer on the insulating layer and the conductor circuit pattern.
(B) A step of opening the resist layer so that only the end face of the resistance element electrode which is a part of the conductor circuit pattern is exposed as a portion where the resistor is provided.
(C) A step of filling the resist layer opening with a resistance paste.
(D) A step of removing the resistance paste protruding beyond the thickness of the resist layer.
(E) A step of curing the resistance paste to form a resistor.
(F) A step of removing the resist layer.

  In the invention according to claim 4 of the present invention, the step (a) of forming the resist layer on the insulating layer and the conductor circuit pattern controls the thickness of the resist layer to be equal to the thickness of the resistor. Therefore, the passive element built-in wiring board manufacturing method according to claim 3, wherein a material whose film thickness is adjusted in advance is used.

  In the invention according to claim 5 of the present invention, before the step (c) of filling the resist layer opening with the resistance paste, a step of performing metal plating in advance on the end face of the resistance element electrode to be in contact with the resistor is added. The method of manufacturing a wiring board with a built-in passive element according to claim 3 or 4, wherein:

  In the invention according to claim 6 of the present invention, the step (d) of removing the resistance paste protruding beyond the thickness of the resist layer removes the resistance paste protruding beyond the thickness of the resist layer, 6. The passive element built-in wiring board manufacturing method according to claim 3, wherein the upper surface is flattened.

The invention according to claim 7 of the present invention includes an insulating layer, a conductor circuit pattern provided on the insulating layer, a capacitor first electrode, a dielectric, and a capacitor second electrode that are part of the conductor circuit pattern. In the method of manufacturing a passive element built-in wiring board having a capacitor, the capacitor is formed by at least the following steps.
(A) A step of forming a resist layer on the insulating layer and the conductor circuit pattern.
(B) A step of opening the resist layer so that only the end face of the capacitor first electrode which is a part of the conductor circuit pattern is exposed as a portion where the dielectric is provided.
(C) A step of filling the resist layer opening with a dielectric paste.
(D) A step of removing the dielectric paste protruding beyond the thickness of the resist layer.
(E) A step of curing the dielectric paste to obtain a dielectric.
(F) A step of removing the resist layer.
(G) forming a capacitor second electrode on the dielectric;

  In the invention according to claim 8 of the present invention, the step (a) of forming a resist layer on the insulating layer and the conductor circuit pattern controls the thickness of the resist layer to be equal to the thickness of the dielectric. 8. The method of manufacturing a passive element built-in wiring board according to claim 7, wherein a material whose film thickness is adjusted in advance is used.

  In the invention according to claim 9 of the present invention, the step (d) of removing the dielectric paste protruding beyond the thickness of the resist layer removes the portion of the dielectric paste protruding beyond the thickness. 9. The manufacturing method of a passive element built-in wiring board according to claim 7, wherein the paste upper surface is a step of flattening.

  According to the manufacturing method of the present invention, since only the end face of the electrode of the conductor circuit pattern is in contact with the resistance material, a resistor having an accurate resistance value can be made as designed. It should be noted that the resistor and the resistor element electrode are connected to the wiring board or the support by connecting the upper surface substantially parallel to the wiring board, the bottom surface contacting the support (that is, the insulating layer) on which the resistor is mounted, and the upper surface to the bottom. And side surfaces that are substantially vertical. Here, this side surface is called an end surface.

  According to the manufacturing method of the present invention, a resistor made of a resistance paste and a dielectric made of a dielectric paste have a resistance after forming in order to make it easy to control the film thickness to a predetermined thickness and to smooth the surface. Passive element built-in wiring boards with small variations in values and capacitance values can be manufactured.

  According to the manufacturing method of the present invention, the resistance value and the capacitance value are set, and the shape can be easily designed, and the variation after formation is small.

  According to the present invention, a resist is patterned by using different masks for each type of resistance paste, the resistance paste is filled, and the resist stripping process is repeated, so that the resistance elements formed by the different resistance pastes are identical. Can be formed on the surface. Alternatively, by filling the openings corresponding to a plurality of resistance elements with a resistance paste with a dispenser or the like, a resistance element having a resistor formed of different types of resistance paste on the same surface is masked once. Can be formed. In addition, by forming a resistive element having a thin resistor first and a resistive element having a thicker resistor later, it is possible to form resistive elements having different thicknesses on the same surface. Similarly, a plurality of capacitors having different dielectric pastes for forming a dielectric can be formed on the same surface. In addition, a plurality of capacitors having different dielectric thicknesses can be formed. Furthermore, by selecting the structure of the element electrode provided in advance and the paste to be filled in the opening, the resistance element and the capacitor element can be formed on the same surface by one time or a plurality of times of masking.

  Hereinafter, embodiments of the present invention will be described in detail.

  First, a manufacturing process when a resistance element is incorporated will be described with reference to FIG.

  FIG. 1A shows a wiring board 2 having a metal conductor circuit pattern 1 patterned on a support such as a glass epoxy substrate and a resistance element electrode 21 which is a part of the conductor circuit pattern.

  In FIG. 1B, a resist layer 8 made of a photosensitive resin is formed on the wiring board 2 by a method such as lamination. Here, the thickness of the resist layer 8 is formed to be equal to the thickness of the desired resistor. The resist layer preferably has a predetermined thickness as a resist in order to adjust the film thickness in advance.

  Next, in FIG. 1C, the opening 11 of the resister resistor installation portion is formed by a step of exposing and curing the formed resist layer using a mask and a step of developing.

  At this time, by forming an electrode of a metal such as silver or gold on the end face of the conductor circuit pattern in contact with the resistor by an electroless plating method or the like, the electrical connection reliability between the resistor and the conductor circuit pattern interface is improved. It is desirable.

  In FIG. 1D, a resist paste such as a carbon paste made of carbon black such as furnace black and a resin such as epoxy is filled in the resist opening. Or it may apply | coat to the whole resist surface containing an opening part. The resistance paste 3 is desirably filled to a thickness equal to or greater than the thickness of the resist layer 8.

  In FIG. 1E, the resistance paste 3 protruding beyond the thickness of the resist layer or the resistance paste 3 on the resist layer appearing from the opening is removed with a doctor bar or the like. At this time, it is preferable not only to remove the protruding resistor paste but also to adjust the upper surface of the resistor paste to the height of the upper surface of the resist and further flatten the upper surface of the resistor paste, because a resistor can be formed with high accuracy. It is also possible to simultaneously fill and remove the resistance paste using the doctor bar.

  Next, the resistance paste is thermally cured in an oven or the like at a temperature lower than the resist heat resistance temperature. When the curing temperature of the resistance paste is equal to or higher than the heat resistance temperature of the resist, it is temporarily cured at a temperature equal to or lower than the heat resistance temperature of the resist to stabilize the shape of the resistance paste.

  Next, in FIG. 1F, the resist layer 8 is peeled from the wiring board 2. Thereafter, when the resistance paste is in a temporarily cured state, it is cured at a predetermined temperature. In this way, the resistor 3 is formed. If necessary, laser trimming or the like is performed, the resistance value is adjusted, and the wiring board 2 on which the resistor 3 made of the resistance paste is formed is formed. Further, an upper layer such as an insulating layer is laminated, and a multilayer wiring board having a built-in resistance element is formed by repeating the above steps (not shown in the drawing).

  As shown in FIG. 1 (f), the resistance element 20 of the present invention includes a resistance element electrode 21 that is a part of the conductor circuit pattern 1, and a resistance element 3 disposed between the resistance element electrodes 21. 3 and each resistance element electrode 21 are connected only at the end face.

  In the formation of the resistor, when different types of resistance paste are formed on the same surface, a resist is opened using a mask corresponding to each resistance paste type, and the process is repeated after the resist is peeled to form on the same surface. It is also possible. Alternatively, by filling the openings corresponding to a plurality of resistance elements with a resistance paste with a dispenser or the like, a resistance element having a resistor formed of different types of resistance paste on the same surface is masked once. Can be formed. In addition, by forming a resistive element having a thin resistor first and a resistive element having a thicker resistor later, it is possible to form resistive elements having different thicknesses on the same surface.

  Next, an implementation process when a capacitor is incorporated will be described with reference to FIG.

  FIG. 2A shows a wiring board 2 having a metal conductor circuit pattern 1 patterned on a support such as a glass epoxy substrate and a capacitor first electrode 31 which is a part of the conductor circuit pattern.

  In FIG. 2B, a resist layer 8 made of a photosensitive resin is formed on the wiring board 2 by a method such as lamination. Here, the thickness obtained by subtracting the conductor circuit pattern thickness from the resist layer thickness is formed to be equal to the thickness of the dielectric.

  Next, in FIG. 2C, the opening 11 of the dielectric layer installation portion of the resist layer is formed by the steps of exposing and curing the formed resist layer using a mask, and developing the resist layer.

  In FIG. 2D, the resist opening 11 is filled with a dielectric paste made of a dielectric filler such as barium titanate and a resin such as epoxy. Or it may apply | coat to the whole resist surface containing an opening part. The dielectric paste is preferably filled to a thickness greater than the resist layer thickness.

  In FIG. 2E, the dielectric paste protruding beyond the thickness of the resist layer or the resist layer-like dielectric paste is removed with a doctor bar or the like so that the step between the upper surface of the dielectric 5 and the resist layer 8 is eliminated. . By using the doctor bar, it is possible to simultaneously fill and remove the dielectric paste.

  The dielectric paste is thermally cured in an oven or the like at a temperature lower than the resist heat resistance temperature. When the curing temperature of the dielectric paste is equal to or higher than the heat resistance temperature of the resist, the dielectric paste is temporarily cured at a temperature equal to or lower than the heat resistance temperature of the resist to stabilize the shape of the dielectric paste.

  In FIG. 2 (f), the resist layer 8 is peeled from the wiring board 2. Thereafter, when the dielectric paste is in a temporarily cured state, it is cured at a predetermined temperature. After forming dielectric 5 made of a dielectric paste, the second electrode of the capacitor is formed by a known method such as screen printing or electroless plating, and connected to a predetermined portion of the conductor circuit pattern, and then an upper layer such as an insulating layer is laminated. To do. In the multilayer substrate, the above steps are repeated. In this way, a wiring board with a built-in capacitor is formed.

  In the formation of the dielectric, when different types of dielectric paste are formed on the same surface, a resist is opened using a mask suitable for each type of dielectric paste, and the process is repeated after the resist is peeled off. It is also possible to form on the same surface. Alternatively, by filling the openings corresponding to a plurality of capacitors with a dielectric paste with a dispenser or the like, a capacitor having a dielectric formed of different types of dielectric paste on the same surface is masked once. Can be formed. In addition, capacitors having different dielectric thicknesses can be formed on the same surface by forming a capacitor having a thinner dielectric first and a capacitor having a thicker dielectric later.

  FIG. 3 is a side sectional view showing the structure of the passive element built-in wiring board of the present invention incorporating a resistance element and a capacitor.

FIG. 3 shows a wiring board with a built-in passive element including a resistive element and a capacitor. The resistor 3 is formed so as to connect the resistor element electrodes 21 to the resistor installation portion of the conductor circuit pattern 1, and the dielectric 5 is formed on the capacitor first electrode 31 that is the dielectric installation portion of the conductor circuit pattern 1. ing. A conductor circuit pattern is formed on the wiring board 2, a capacitor 30 is formed on the right side of the figure, and a resistance element 20 is formed on the left side. In the capacitor, the dielectric 5 is formed on the surface of the capacitor first electrode 31, and the capacitor second electrode 7 is formed on the surface of the dielectric 5 and the other conductor circuit pattern to form a capacitor circuit. To do. The resistor 3 is formed with a resistor 3 so as to be in contact with a side end of one resistor element electrode and a side end of the other resistor element electrode, thereby forming a circuit of the resistor element. In FIG. 3, three wiring layers are formed on the wiring board 2, the second layer is a capacitor circuit only, and the third layer is a passive element built-in wiring board 40 containing only a resistance element. is there.

  As shown in FIG. 1F, the capacitor 30 of the present invention includes a capacitor first electrode 31 that is a part of one conductor circuit pattern 1, a dielectric 5 formed on the upper surface 31 of the capacitor first electrode, A part of the other conductor circuit pattern 1 is connected from the upper surface of the dielectric 5 and is formed of a conductor that functions as the capacitor second electrode 7.

  The manufacturing method of the passive element built-in wiring board having the structure of FIG. 3 is formed by the manufacturing method of FIGS.

The manufacturing process figure of the internal resistance element of this invention. The manufacturing process figure of the built-in capacitor of this invention. Sectional drawing which shows the structure of the wiring board with a built-in passive element of this invention. Sectional drawing which shows the structure of the conventional wiring board with a built-in resistor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Conductor circuit pattern 2 ... Wiring board 3 (it is a support body) ... Resistor 3a (it consists of resistance paste) ... Resistor 5 ... (it consists of resistance paste) Dielectric 5a ... (it consists of dielectric paste) Dielectric 7 ... capacitor second electrode 8 ... resist layer 9 ... insulating layer 10 ... resistance silver electrode 11 ... opening 20 ... resistance element 21 ... resistance element electrode 30 ... capacitor 31 ... capacitor first electrode 40 ... Device built-in wiring board

Claims (9)

Passive element built-in wiring board having an insulating layer, a conductive circuit pattern provided on the insulating layer, a resistive element electrode that is part of the conductive circuit pattern, and a resistive element that connects the resistive element electrodes The resistor and the resistor element electrode are connected only at respective end faces, the resistor is thicker than the resistor element electrode, and the resistor has a flattened upper surface. Passive element built-in wiring board.
  The conductor circuit pattern further includes a capacitor first electrode as a part thereof, a dielectric formed on the capacitor first electrode, and a capacitor second electrode on the dielectric. The wiring board with a built-in passive element according to 1. Passive element built-in wiring board having an insulating layer, a conductive circuit pattern provided on the insulating layer, a resistive element electrode that is part of the conductive circuit pattern, and a resistive element that connects the resistive element electrodes In this manufacturing method, the resistive element is formed by at least the following steps.
(A) A step of forming a resist layer on the insulating layer and the conductor circuit pattern.
(B) A step of opening the resist layer so that only the end face of the resistance element electrode which is a part of the conductor circuit pattern is exposed as a portion where the resistor is provided.
(C) A step of filling the resist layer opening with a resistance paste.
(D) A step of removing the resistance paste protruding beyond the thickness of the resist layer.
(E) A step of curing the resistance paste to form a resistor.
(F) A step of removing the resist layer.   (A) The step of forming the resist layer on the insulating layer and the conductor circuit pattern is made of a material whose thickness is adjusted in advance in order to control the thickness of the resist layer to be equal to the thickness of the resistor. The method of manufacturing a wiring board with a built-in passive element according to claim 3, wherein the wiring board is used.   The step of performing metal plating in advance on the resistance element electrode end face to be in contact with the resistor is added before the step of (c) filling the resist layer opening with the resistance paste, or 4. A method for producing a passive element built-in wiring board according to 4.   (D) The step of removing the resistive paste that has protruded beyond the thickness of the resist layer is a step of planarizing the upper surface of the resistive paste while removing the resistive paste that has exceeded the thickness of the resist layer. A method for producing a passive element built-in wiring board according to any one of claims 3 to 5. Manufacturing of Passive Element Built-In Wiring Board Having Insulating Layer, Conductor Circuit Pattern Provided on the Insulating Layer, and Capacitor Composed of Capacitor First Electrode, Dielectric and Capacitor Second Electrode as Part of Conductor Circuit Pattern In the method, a capacitor is formed by at least the following steps.
(A) A step of forming a resist layer on the insulating layer and the conductor circuit pattern.
(B) A step of opening the resist layer so that only the end face of the capacitor first electrode which is a part of the conductor circuit pattern is exposed as a portion where the dielectric is provided.
(C) A step of filling the resist layer opening with a dielectric paste.
(D) A step of removing the dielectric paste protruding beyond the thickness of the resist layer.
(E) A step of curing the dielectric paste to obtain a dielectric.
(F) A step of removing the resist layer.
(G) forming a capacitor second electrode on the dielectric; (A) The step of forming a resist layer on the insulating layer and the conductor circuit pattern uses a material whose thickness is adjusted in advance in order to control the thickness of the resist layer to be equal to the thickness of the dielectric. The method for manufacturing a wiring board with a built-in passive element according to claim 7.   (D) the step of removing the dielectric paste protruding beyond the thickness of the resist layer is a step of flattening the upper surface of the dielectric paste while removing the portion of the dielectric paste protruding beyond the thickness. The method for manufacturing a wiring board with a built-in passive element according to claim 7 or 8.

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