JP2008288298A - Method for manufacturing printed wiring board with built-in electronic components - Google Patents

Abstract

In a conventional wiring board with built-in components, the base material on which active components and passive components are mounted is in a semi-cured state and does not include a glass cloth, so that handling at the time of manufacture is poor and product reliability is also adversely affected There is a problem that affects. In addition, since the periphery of the electronic component is covered with resin, there is a problem that it is difficult to control the heat of the active component and the reliability of the operation of the component is impaired.
A multilayer printed wiring board comprising an insulating layer and a wiring layer includes a first conductive layer on one surface of the first insulating layer and a second conductive layer having a wiring pattern formed on the other surface. And an electronic component is formed on the wiring pattern, and the first insulating layer has an opening that is open so that a part of the first conductive layer is exposed. The exposed portion of the first conductive layer and the electronic component A printed wiring board, wherein the second wiring pattern is electrically connected to the second wiring pattern at an opening, and an electronic component is embedded by a second insulating layer formed on the other surface.
[Selection] Figure 2

Description

  The present invention relates to a method for manufacturing a printed wiring board having an electronic component including an active element and a passive element, and more particularly to a method for manufacturing a printed wiring board corresponding to high frequency, high density, small size, and thinning of a semiconductor device. It is about.

  In recent years, demands for improving the wiring density of printed wiring boards have increased with the trend of electronic devices to become smaller, thinner and more functional. In response to these requirements, active development of component-embedded printed wiring boards that incorporate active components such as semiconductors and passive components such as chip capacitors has been actively conducted. The printed wiring board with built-in components can be expected to improve high-frequency characteristics by shortening the mounting area and electrical wiring.

  Hereinafter, an example of the structure and manufacturing method of a conventional component built-in printed wiring board will be described with reference to FIGS.

  First, as shown in FIG. 1A, a sheet 100 is formed by processing a mixture of an inorganic filler and a semi-cured thermosetting resin into a sheet having a constant thickness. Next, a hole 101a for a via hole is formed on the sheet with a carbon dioxide laser or the like, and then the hole is filled with a conductive paste to form the via hole 101. As the conductive paste, a paste to which conductive particles such as copper particles are added is used, and a screen printing method is used for filling.

  Next, as shown in FIG. 1 (b), a release carrier 102 made of a copper foil having a thickness of 70 μm is prepared, and a metal film is formed on the upper surface of the carrier by electrolytic copper plating. Etching is performed to form a wiring pattern 103. Thereafter, an electronic component is mounted on the release carrier by solder bonding.

  Next, as shown in FIG. 1C, a release carrier on which the semiconductor 104 and the chip component 105 are mounted and a release carrier 107 having only a separately prepared wiring pattern 106 are aligned with the sheet 100, and both The semiconductor substrate 104 and the chip component 105 are embedded in the sheet by sandwiching the sheet 100 from above and below so that the wiring patterns 103 and 106 face the sheet 100 side, and laminating and heating and pressing.

  Next, as shown in FIG. 1D, the release carrier on the front and back sides of the sheet 100 is peeled from the sheet to form the core layer 108 in which the components are built.

Next, in order to form a multilayer wiring layer using the core layer 108 containing the semiconductor 104 and the chip part 105, a conductive paste is filled in the hole for the via hole as in the case shown in FIG. Then, the sheet 109 formed by forming the via hole 109a is aligned as shown in FIG. 1 (e), overlapped from the upper and lower surfaces of the core layer 108, and integrated by heating and pressing. Thereafter, metal films 111 and 112 such as copper are formed on the outer surface of the sheet, and the metal films are etched by photolithography to form wiring patterns 113 and 114 as shown in FIG. As a result, a wiring board with a built-in component is obtained.
Japanese Patent Laid-Open No. 2002-261449

  In the conventional component built-in wiring board as described above, the base material on which the active component and the passive component are mounted is in a semi-cured state and does not include a glass cloth, so that handling is bad and the reliability of the product is also adversely affected. There is. In addition, since the periphery of the electronic component is covered with resin, there is a problem that reliability of the operation of the component is impaired because it is difficult to control the heat of the active component, which particularly causes heat generation during operation.

  Moreover, in the above-described component-embedded substrate, there is a problem that the manufacturing cost accompanying an increase in material cost and manufacturing process is increased by using a special film such as a release carrier.

  The object of the present invention is to solve the above-mentioned conventional problems, and it has good handling at the time of manufacture, and the reliability of the embedded electronic component and the connection reliability between the component and the conductive layer are also achieved. It is an object of the present invention to provide a component-embedded printed wiring board that incorporates a small and thin electronic component that can be secured and enables high-density wiring.

  In the invention according to claim 1 of the present invention, in the multilayer printed wiring board comprising the insulating layer and the wiring layer, the first conductive layer is formed on one surface of the first insulating layer, and the wiring pattern is formed on the other surface. An electronic component is formed on the wiring pattern, and the first insulating layer has an opening opened so that a part of the first conductive layer is exposed. The exposed portion of the layer is electrically connected to the second wiring pattern on which the electronic component is formed, and the electronic component is embedded by the second insulating layer formed on the other surface. It is a printed wiring version.

  Thus, since the conductive layer is not formed in the opening on both surfaces of the insulating layer on which the electronic component is mounted, a favorable opening can be formed using a carbon dioxide gas laser. Furthermore, since a core-like base material in which a wiring pattern is formed on the insulating layer can be used, handling at the time of manufacture becomes good.

  The invention according to claim 2 of the present invention is that, in the invention according to claim 1, a thermal via is formed in the opening to electrically connect the pattern of the pad of the electronic component and the first conductive layer. It is the printed wiring board characterized.

  In the first insulating layer, a pad on which an electronic component is previously placed on the wiring pattern is formed by a photolithography method or the like, so that the second conductive layer having the wiring pattern formed on the insulating layer is not provided. A hole can be easily formed using a carbon dioxide laser, and a thermal via excellent in heat dissipation can be provided directly under the pad by filling the hole with a paste having high thermal conductivity.

  The invention according to claim 3 of the present invention is characterized in that, in the invention according to claim 1, the first conductive layer is formed of a metal film and is adhered by a film-like or liquid adhesive. Is a printed wiring board.

  By applying a film or liquid adhesive in advance to the side of the first insulating layer where the wiring pattern is not formed, the metal film formed of copper foil or the like can be made conductive without special heating and pressing. It can be formed as a layer.

  The invention according to claim 4 of the present invention is the printed circuit board according to any one of claims 1 to 3, wherein the electronic component is an IC chip as an active element or a package substrate incorporating the IC chip. is there.

In the invention according to claim 5 of the present invention, the electronic component is a multilayer ceramic capacitor, a chip resistor,
5. The printed wiring board according to claim 1, wherein the printed wiring board is a package substrate including any passive element of a chip inductor.

  The invention according to claim 6 of the present invention is characterized in that, in a package substrate including at least one of an active element and a passive element as electronic components, the active element and the passive element are connected to different wiring layers. The printed wiring board according to claim 1.

  By connecting active and passive elements to different wiring layers, a three-dimensional structure is possible, which increases design flexibility in the placement of parts with different heights, contributing to further miniaturization and thinning of the board itself. In addition to this, it is possible to optimize the signal wiring to cope with the operation of the electronic component.

  The invention according to claim 7 of the present invention is the printed wiring board according to claim 1, wherein the printed wiring board has a through hole penetrating the insulating layer and the wiring layer.

  Thereby, since the freedom degree of wiring routing is increased in the connection between the active element and the passive element, the signal wiring can be optimized.

  Since the printed wiring board according to the present invention has such a configuration, the second insulating layer in which the electronic component is embedded can be manufactured separately from the first insulating layer, and the first insulating layer is in a semi-cured state. There is no need to do. In addition, a favorable opening can be formed in the first insulating layer using a carbon dioxide laser or the like without the conductive layer. Furthermore, since it can manufacture using the core-shaped base material which formed the wiring pattern in the 1st insulating layer, handling property becomes favorable.

  Furthermore, since thermal vias with excellent heat dissipation can be formed directly under the pads of electronic components where heat generation is a problem, the operational reliability of the components can be improved. Furthermore, since electronic components can be arranged in multiple layers, it not only contributes to the miniaturization and thinning of the substrate itself, but also can optimize the signal wiring to respond to the operation of the electronic components. A component-embedded board with improved characteristics can be provided. Thus, in recent years when the printed wiring board is required to be reduced in size and increased in density, there is a great effect in responding to space saving and higher density in the surface mounting portion.

  An example of an embodiment of a printed wiring board according to the present invention will be described in detail below based on the drawings (FIGS. 2 and 3).

  First, as shown in FIG. 2 (a), a flat core substrate 200 having a certain thickness made of an electrical insulating material is prepared, and a conductor such as a copper foil is formed on one side of the substrate 200, This is etched by a photolithography method or the like to form a wiring pattern 201.

  Further, as shown in FIG. 2B, an adhesive film 202 having one surface protected by a release film 203 is bonded to the base 200 on the surface where the wiring pattern is not formed.

  Next, as shown in FIG. 2C, a portion where the chip capacitor is arranged on the surface of the base material 200 is punched with a drill or the like to form an opening 204a. Also, a thermal via hole 205a is formed using a carbon dioxide laser from the surface where the wiring pattern is not formed under the pad where the LSI bare chip is placed.

Next, as shown in FIG. 2D, the hole is filled with a conductive paste using a screen printing method, and a thermal via 205 is formed. Next, the release film 203 is peeled off, and a conductive film 206 such as a copper foil is bonded to the adhesive film surface. Next, silver plating 204b is applied to the surface of the chip capacitor connecting portion 204 exposed by forming the opening 204a.

  Next, as shown in FIG. 2E, the LSI bare chip chip 207 is connected to the wiring pattern 201a on the substrate 200 by heat and pressure using the die bond film 207a and mounted. Further, the chip capacitor 208 is connected to the chip capacitor connecting portion 204 by applying heat and pressure using an ACF (Anisotropic Conductive Film) 208a.

  Next, as shown in FIG. 2 (f), wiring patterns 209a and 209b are formed on the front and back surfaces for the uppermost layer and the inner layer, and the base material 209 in which the front and back surfaces of the insulating layer are electrically connected by the through-through holes 209c is formed. prepare. At this time, the resistor element 210 is formed in advance by screen printing and baking a resistor paste formed by mixing carbon powder in a thermosetting resin on the wiring pattern 209b.

  Furthermore, a semi-cured base material 211 in which a glass cloth is impregnated with an epoxy resin is prepared. In the base material 209 on which the base material 211 and the inner layer pattern are formed, openings corresponding to the placement positions of the chip capacitor 208 and the LSI bare chip 207 are prepared. 212a and 212b are formed by punching, and a semi-cured base material 211 and a base material 209 are stacked on the base material 200 on the electronic component mounting surface side. At this time, the number and thickness of the semi-cured base materials 211 are adjusted so that the base material 209 layer as the uppermost layer does not become lower than the upper surfaces of the chip capacitor 208 and the LSI bare chip 207. Further, a semi-cured epoxy resin 213 having no glass cloth without punching is laminated on the base material 209 so that the chip capacitor 208 and the LSI bare chip 207 are not exposed.

  Thereafter, the base material 200 on which the electronic components are mounted, and 209, 211, and 213 are heated and pressed from above and below to insulate the resistance element 210, the LSI bare chip 207, and the chip capacitor 208 as shown in FIG. It is embedded in a state sealed with layers 209, 211, and 213.

  Next, as shown in FIG. 2I, via holes 214a for connecting the LSI bare chip 207 are formed in the insulating layer 213 that seals the LSI bare chip 207 by a carbon dioxide laser, and the holes 214a Via holes 214 are formed by applying electroless copper plating to the inner wall. Further, through holes 215a that penetrate the insulating layers 209, 211, and 213 and the base material 200 in the stacking direction are formed by a drill, and through holes 215 are formed by performing electroless copper plating. Simultaneously with the electrical connection, a copper plating layer (not shown) such as copper is formed on the outer surface of the insulating layer 213. Both surfaces of the conductive film 206 formed on the base material 200 side on which the copper plating layer and the electronic component are mounted are etched by a photolithography method or the like to form a wiring pattern 206b including the connection terminals 206a of the chip capacitor 208.

  Next, a solder resist layer 218 is formed leaving the external connection terminals 217 of the wiring pattern, and nickel gold plating is applied to the external connection terminals 217. Thereby, as shown in FIG. 2J, a printed wiring board 219 with a built-in component can be formed.

It is a schematic cross section which shows an example of the manufacturing process of the conventional component built-in board | substrate. It is a schematic cross section which shows the manufacturing process of the component built-in board in one embodiment of this invention.

Explanation of symbols

100, 109, 110 ... Semi-cured sheet 101, 109a, 110a ... Via hole 102, 107 ... Release carrier 103, 106, 113, 114 ... Conductive layer (wiring pattern)
104... Semiconductor chip 105... Chip component 108... Core layer 111, 112... Conductor layer 200, 209.
201, 206a, 209a, 209b ... conductive layer (wiring pattern)
202 ... Adhesive layer 203 ... Release carrier 204 ... Openings 204a, 212a, 212b ... Openings 204b ... Chip component connection (silver plating)
205, 214 ... via holes 205a, 214a ... via hole 206 ... conductive layer 207 ... semiconductor chip (LSI bare chip)
207a ... Die bond film (for semiconductor connection)
208 ... Chip parts (multilayer ceramic capacitors)
208a ... ACF (for chip component connection)
210... Resistance elements 211 and 213... Semi-cured base material 215... Through hole 215 a... Through hole 217... External connection terminal 218. Built-in board

Claims (7)

  A multilayer printed wiring board comprising an insulating layer and a wiring layer, comprising: a first conductive layer on one surface of the first insulating layer; and a second conductive layer having a wiring pattern formed on the other surface. An electronic component is formed on the first insulating layer, and the first insulating layer has an opening that is open so that a part of the first conductive layer is exposed. The exposed portion of the first conductive layer and the electronic component are formed. A printed wiring board, wherein the second wiring pattern is electrically connected through an opening, and an electronic component is embedded by a second insulating layer formed on the other surface.   2. The printed wiring board according to claim 1, wherein a thermal via is formed in the opening to electrically connect the pad pattern of the electronic component and the first conductive layer.   3. The printed wiring board according to claim 1, wherein the first conductive layer is formed of a metal film and is adhered by a film or liquid adhesive.   The printed wiring board according to any one of claims 1 to 3, wherein the electronic component is an IC chip which is an active element or a package substrate incorporating the IC chip.   5. The printed wiring board according to claim 1, wherein the electronic component is a package substrate including a passive element of any one of a multilayer ceramic capacitor, a chip resistor, and a chip inductor.   2. The printed wiring board according to claim 1, wherein the active element and the passive element are connected to different wiring layers in a package substrate including at least one active element and passive element that are electronic components.   The printed wiring board according to claim 1, further comprising a through hole penetrating the insulating layer and the wiring layer.