JP4480418B2 - Wiring board - Google Patents

Description

  The present invention relates to a wiring board for mounting a semiconductor element such as a semiconductor integrated circuit element or an optical semiconductor element, a vibrator such as a piezoelectric vibrator or a crystal vibrator, and other various electronic components.

  Conventionally, for example, a semiconductor substrate such as a semiconductor integrated circuit element or an optical semiconductor element, a vibrator such as a piezoelectric vibrator or a crystal vibrator, and a wiring board for mounting various other electronic components have been made of an aluminum oxide sintered body or the like. Insulating substrate having a mounting portion on which an electronic component is mounted on the upper surface, an electrode pad formed on the mounting portion and electrically connected to the electronic component, and a different insulating layer A ground conductor layer and a power conductor layer formed between the layers, a through conductor that electrically connects the ground conductor layer and the power conductor layer to a corresponding electrode pad, and a ground conductor layer and a power conductor among the electrode pads The structure includes a wiring conductor formed from a layer that is not electrically connected (for connecting a signal electrode or the like) to at least one of a side surface and a lower surface of the insulating substrate. Note that conductors for leading the ground conductor layer and the power supply conductor layer to the side surface and the bottom surface of the insulating substrate are formed on the inside and the outer surface of the insulating substrate, respectively.

  An electronic component is mounted on the mounting portion on the upper surface of the insulating substrate, and the signal, grounding, and power supply electrodes of the electronic component are electrically connected to the corresponding electrode pads via conductive connection materials such as solder. Connected.

  Of each electrode of the electronic component connected to the electrode pad, the signal one is led out to the side surface and the bottom surface of the insulating substrate through the wiring conductor, and the one for grounding and the power source is the ground conductor layer through the through conductor And electrically connected to the power supply conductor layer.

And by sealing the electronic component mounted on the mounting part with a lid or sealing resin,
An electronic device used as an arithmetic component of an electronic device such as a PA module or an FE module for a cellular phone is completed.

  For this electronic device, by electrically connecting the lead-out portion of the conductor and the lead-out portion of the wiring conductor for leading the ground conductor layer and the power supply conductor layer to the side surface and the bottom surface of the insulating substrate, respectively, The electrodes for signal, grounding, and power supply of the electronic component are electrically connected to corresponding external electric circuits.

When forming an electronic device mounted on an electronic device such as a PA module, a large number of capacitive elements are mounted on the mounting portion for stable power supply, filtering, and the like. Each capacitive element has a structure in which electrodes are formed on two opposing sides of a rectangular parallelepiped insulating base made of a ceramic sintered body, and one of the electrodes is electrically connected to the ground conductor layer, and the other is It is electrically connected to the power supply conductor layer.
JP 2001-35960 A JP-A-10-256420

  However, in recent years, the number of ceramic layers that form an insulating base has increased significantly in response to an increase in the number of electronic components to be mounted and higher functionality of individual electronic components. With the progress of micro wiring, the grounding conductor layer and the power supply conductor layer can no longer be formed in the shallow layer inside the insulating substrate, and the number of ceramic layers from the connection pad to the grounding conductor layer and the power supply conductor layer is two. As a result, it has become very large. When the number of ceramic layers from the connection pad to the grounding conductor layer and the power supply conductor layer increases, the distance from the power supply conductor layer (and the grounding conductor layer) to the electrode increases. There was a problem that the efficiency would be worse if performed reliably.

Further, in the case of an electronic device used in the above-described mobile phone application PA module, FE module, etc., it is necessary to electrically connect the electrodes of a large number of capacitive elements to the ground conductor layer and the power supply conductor layer. , To secure a space for forming electrodes on the main surface of the insulating substrate, and to secure a space in the insulating substrate for forming a through conductor that electrically connects each electrode to the ground conductor layer and the power supply conductor layer. There was a problem that it was extremely difficult. For this reason, there is a problem that it is difficult to reduce the size and density of the wiring board.

  In addition, since a capacitive element mounted for such stable power supply and filtering needs to be electrically connected to the ground conductor layer and the power conductor layer with low resistance, if a long through conductor is interposed, This causes a problem that the characteristics deteriorate.

  The present invention has been completed in view of the above-mentioned problems in the prior art. The purpose of the present invention is to increase the number of ceramic layers that form the insulating base of a wiring board as the functionality of electronic components increases. Another object of the present invention is to provide a wiring board capable of connecting a ground conductor layer and a power supply conductor layer and an electrode of an electronic component with low electrical resistance.

  In addition, an object of the present invention is to mount a large number of capacitive elements, for example, when forming an electronic device used for a mobile phone or the like, and electrically connect the electrodes of the capacitive elements to the ground conductor layer and the power supply conductor layer. Even when it is necessary to connect, an electrode pad for connecting an electrode can be easily formed correspondingly, and the electrode pad can be reliably connected to the ground conductor layer and the power supply conductor layer with low resistance. It is an object of the present invention to provide a line substrate that can be connected to each other and can be miniaturized.

The wiring board of the present invention is formed by laminating a plurality of insulating layers, and has an insulating substrate having an electronic component mounting portion on an upper surface and side surfaces thereof, and is formed on the mounting portion on the upper surface of the insulating substrate to electrically connect the electronic component. Connected to the electrode pad, a wiring conductor formed from the electrode pad to at least one of the side surface and the lower surface of the insulating substrate, and an end between the different layers of the insulating layer on the mounting portion on the side surface of the insulating substrate The grounding conductor layer and the power supply conductor layer, each of which is formed so as to reach the outer peripheral portion of the insulating substrate, are thinner than the thickness of the central portion, and the mounting portion on the side surface of the insulating substrate is provided with the grounding conductor layer. A grounding pad formed in contact with the end, and a power supply pad formed in contact with the end of the power supply conductor layer on the side surface of the insulating substrate are provided.

According to the wiring board of the present invention, a plurality of insulating layers are stacked, an insulating substrate having an electronic component mounting portion on the upper surface and side surfaces, and an electronic component formed on the mounting portion on the upper surface of the insulating substrate. An electrode pad connected to the electrode, a wiring conductor formed from the electrode pad to at least one of the side surface and the lower surface of the insulating substrate, and an end between different layers of the insulating layer so that the end reaches the mounting portion on the side surface of the insulating substrate. A grounding conductor layer and a power supply conductor layer whose thickness at the outer peripheral portion of the insulating substrate is thinner than the thickness at the central portion, and a grounding pad formed on the side surface of the insulating substrate in contact with the end of the grounding conductor layer And a power supply pad formed on the side surface of the insulating substrate in contact with the end of the power supply conductor layer, between the grounding pad and the grounding conductor layer, and between the power supply pad and the power supply conductor layer, Between Since each of the electrodes for grounding the electronic component and the power source are electrically connected to the pad for grounding and the pad for power supply, respectively, and the electrodes for grounding the electronic component and the power supply are grounded. The conductor layer and the power source conductor layer can be electrically connected to each other with a very short connection distance (about the thickness of the grounding pad and the power source pad). Thereby, the ground conductor layer and the power supply conductor layer and the electrode of the electronic component can be connected with low electrical resistance. In addition, since the thickness of the ground conductor layer and the power conductor layer at the outer peripheral portion of the insulating substrate is smaller than the thickness at the central portion, the thick ground conductor layer and the power conductor layer are formed between the insulating layers in the outer peripheral portion of the insulating substrate. It is possible to effectively prevent the occurrence of poor adhesion between layers due to intervening in the wiring, and to form a wiring board excellent in mechanical strength of the insulating board, reliability such as hermetic sealing, etc. it can.

  In addition, according to the wiring board of the present invention, the electronic component mounting portion is provided on the side surface of the insulating substrate, and the end portions of the ground conductor layer and the power supply conductor layer reach the mounting portion on the side surface. For example, when an electronic device used for a PA (power amplifier) module or an FE (front end) module for a mobile phone is formed, etc. Even when a large number of capacitive elements (not shown) are mounted and the electrodes of the capacitive elements need to be electrically connected to the ground conductor layer and the power supply conductor layer, The electrode pad can be easily formed on the mounting portion on the side surface of the insulating substrate, and the electrode pad can be directly electrically connected to the ground conductor layer and the power supply conductor layer. Therefore, it is necessary to easily secure a space for mounting a large number of electronic components such as capacitive elements without increasing the size of the insulating substrate in plan view, and to secure a space for forming a separate through conductor. Absent. As a result, it is possible to provide a wiring board that can reliably connect the electrode pads to the ground conductor layer and the power supply conductor layer with low electrical resistance and can be miniaturized.

  The wiring board of the present invention will be described below with reference to the accompanying drawings. FIG. 1A is a side view showing an example of an embodiment of a wiring board according to the present invention, and FIG. 1A and 1B, 1 is an insulating substrate formed by laminating a plurality of insulating layers, 2 is an electrode pad, 3 is a wiring conductor, 4 is a grounding conductor layer, 5 is a power supply conductor layer, and 6 is grounded. Pad 7 and a power pad 7. The insulating substrate 1, electrode pad 2, wiring conductor 3, ground conductor layer 4, power supply conductor layer 5, grounding pad 6 and power supply pad 7 basically constitute the wiring board of the present invention.

  The insulating substrate 1 is made of an electrically insulating material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, a silicon nitride sintered body, a silicon carbide sintered body, or a glass ceramic sintered body. A plurality of insulating layers are stacked, and a mounting portion for mounting electronic components is provided on the upper surface and side surfaces.

  Each insulating layer is preferably formed of the same material in order to ensure good productivity. For example, when each insulating layer is made of an aluminum oxide sintered body, the insulating substrate 1 is manufactured as follows.

  First, an appropriate organic binder and solvent are added to and mixed with raw material powders such as aluminum oxide, silicon oxide, calcium oxide, and magnesium oxide to produce a slurry ceramic slurry. A ceramic green sheet (ceramic green sheet) is obtained by forming a sheet by employing the sheet forming technique. Thereafter, ceramic green sheets are laminated in the predetermined order in the vertical direction to form a green ceramic molded body. The green ceramic body is fired at a high temperature of about 1600 ° C. in a reducing atmosphere, whereby the insulating substrate 1 is manufactured. Note that some of the plurality of insulating layers may be formed using different materials.

  The insulating substrate 1 is mounted on the upper surface for mounting semiconductor elements such as semiconductor integrated circuit elements and optical semiconductor elements, vibrators such as piezoelectric vibrators and crystal vibrators, and other various electronic components (not shown). The electrode pad 2 is formed on the mounting portion on the upper surface. A wiring conductor 3 is formed from each electrode pad 2 to at least one of the side surface and the lower surface of the insulating substrate 1.

  Electrodes for signals of electronic components mounted on the mounting portion are connected to the electrode pad 2 and at least one of the side surface and the lower surface of the insulating substrate 1 from the electrode pad 2 through the wiring conductor 3 (only the lower surface in the example of FIG. 1). ).

  By connecting a portion of the wiring conductor 3 exposed on the side surface and the lower surface of the insulating substrate 1 to an external electric circuit via a conductive connecting material such as solder, an electrode (for signal) of the electronic component is externally connected. It is electrically connected to the electrical circuit.

  These wiring conductors 3 and electrode pads 2 are made of a metal material such as tungsten, molybdenum, manganese, copper, silver, or palladium. For example, when made of tungsten, a conductive paste of tungsten becomes an insulating layer of the insulating substrate 1. It is formed by printing a predetermined pattern on the ceramic green sheet by a screen printing method or the like.

The insulating substrate 1 also has electronic component mounting portions on the side surfaces, and a ground conductor layer 4 in which the thickness of the outer peripheral portion of the insulating substrate 1 is smaller than the thickness of the central portion between different layers of the insulating layer. And the power supply conductor layer 5 is formed.

  The ground conductor layer 4 and the power conductor layer 5 are formed so that the ends reach the mounting portion on the side surface of the insulating substrate 1, and the insulating substrate is in contact with the ends of the ground conductor layer 4 and the power conductor layer 5. A grounding pad 6 and a power supply pad 7 are formed on the mounting portion on one side surface.

  The grounding pad 6 and the power supply pad 7 are electrically and mechanically connected to the grounding electrode and the power supply electrode of the corresponding electronic component via a conductive connecting material such as solder.

  The ground conductor layer 4 and the power supply conductor layer 5 have a function of grounding the electronic component and supplying power and operating the electronic component normally.

  In this case, the grounding conductor layer 4 and the power supply conductor layer 5 need to have as large an area as possible in order to effectively ground the electronic component and supply power, so that the grounding conductor layer 4 and the power supply conductor layer 5 cover almost the entire surface between one layer of the insulating layers. It is formed with a wide area. Accordingly, in order to ensure electrical insulation between the ground conductor layer 4 and the power supply conductor layer 5, it is necessary to form both layers between different insulating layers.

  The ground conductor layer 4 and the power supply conductor layer 5 are connected to the external electric circuit, for example, inside or outside the insulating substrate 1 and from the ground conductor layer 4 and the power supply conductor layer 5 to the side surface or the bottom surface of the insulating substrate 1, respectively. A conductor (not shown) is formed so as to be led out, and means such as connecting the lead-out portion of the conductor to an external electric circuit can be used.

  Then, for example, a first electronic component (not shown) such as a semiconductor element or an oscillator is mounted on the mounting portion on the upper surface of the insulating substrate 1, and an electrode for signals of the first electronic component is the electrode pad 2. Are electrically connected to each other through a conductive connecting material such as solder, and a second electronic component such as a capacitive element is mounted on the mounting portion on the side surface of the insulating substrate 1 and is used for grounding the second electronic component. By electrically and mechanically connecting the electrode to the grounding pad and the power supply electrode to the power supply pad, respectively, and then sealing the electronic components mounted on each mounting part with a lid or sealing resin Thus, an electronic device used as an arithmetic component of an electronic device such as a PA module or an FE module for a cellular phone is completed.

  The ground conductor layer 4, the power supply conductor layer 5, the grounding pad 6, and the power supply pad 7 can be formed by the same method using the same metal material as the wiring conductor 3 and the electrode pad 2. For example, a conductive paste of tungsten can be formed by printing, filling and filling the surface of a ceramic green sheet serving as an insulating layer of an insulating substrate, or a through-hole previously formed in the ceramic green sheet. .

According to the wiring board of the present invention, the ground conductor 4 and the power supply conductor layer 5 are formed such that the end reaches the mounting portion on the side surface of the insulating substrate 1 and the outer peripheral portion of the insulating substrate 1 is thinner than the central portion. They were respectively, from each to the formation of the grounding pad 6 and the power supply pads 7 on the end portions, between the grounding pad 6 and the ground conductor layer 4, and a power source pad 7 and the power supply conductor layer 5 Since the electrodes are directly connected to each other, the electrodes for grounding and power supply of the electronic component are electrically connected to the grounding pad 6 and the power supply pad 7, respectively, so that the grounding and power supply of the electronic component are connected. Each electrode can be electrically connected to the ground conductor layer 4 and the power supply conductor layer 5 with a very short connection distance (about the thickness of the grounding pad 6 and the power supply pad 7). Thereby, the ground conductor layer 4 and the power supply conductor layer 5 and the electrode of an electronic component can be connected with low electrical resistance. Further, since the thickness of the ground conductor layer 4 and the power supply conductor layer 5 at the outer peripheral portion of the insulating substrate 1 is thinner than the thickness at the central portion, the thick ground conductor layer 4 and the power supply conductor layer are formed at the outer peripheral portion of the insulating substrate 1. Wiring having excellent reliability such as mechanical strength and hermetic sealing of the insulating substrate 1 can be effectively prevented from causing poor adhesion between the layers due to the interposition of 5 between the insulating layers. A substrate can be formed.

  Further, according to the wiring board of the present invention, the mounting portion for the electronic component is provided on the side surface of the insulating substrate 1 and the end portions of the ground conductor layer 4 and the power supply conductor layer 5 reach the mounting portion on the side surface. In addition, since the grounding pad 6 and the power supply pad 7 are formed to correspond to the end portions, for example, in the case of forming an electronic device used for a PA module, an FE module, etc. for a cellular phone, there are many Even when it is necessary to electrically connect the electrodes of the capacitive element to the ground conductor layer 4 and the power supply conductor layer 5 in the case where the capacitive element is mounted, grounding for connecting a large number of capacitive element electrodes corresponding thereto The pad 6 and the power supply pad 7 can be easily formed on the mounting portion on the side surface of the insulating substrate 1, and the grounding pad 6 and the power supply pad 7 are directly connected to the ground conductor layer 4 and the power supply conductor layer 5. Electrical connection It can be. For this reason, a space for mounting a large number of electronic components such as capacitive elements can be easily secured without increasing the size of the insulating substrate 1 in plan view, and a space for separately forming a through conductor is provided. There is no need to secure inside. As a result, it is possible to provide a wiring board that can reliably connect the grounding and power supply electrodes of the electronic component to the grounding conductor layer 4 and the power supply conductor layer 5 and that can be miniaturized. .

Incidentally, the ground conductor layer 4 and the power supply conductor layer 5, the thickness at the outer peripheral portion of the insulating base plate 1, contact and thinner than the thickness at the central portion Ku.

For the ground conductor layer 4 and the power supply conductor layer 5, since the keep thinner than the thickness at the middle central portion thickness at the outer peripheral portion of the insulating base plate 1, at the outer peripheral portion of the insulating base plate 1, a thick ground conductor layer 4 and power supply conductor layer 5 can be effectively prevented that the interlayer adhesion failure occurs due to intervening interlayer insulating layer, reliability such as mechanical strength and hermetic sealing of the insulating base plate 1 it is possible to form the wiring board excellence in sex.

  The ground conductor layer 4 and the power supply conductor layer 5 do not have to be formed so that their ends reach the side surface of the insulating substrate 1 over the entire circumference, and the ground conductor layer is interposed via the grounding pad 6 and the power supply pad 7. 4 and the power supply conductor layer 5 are prevented from being electrically short-circuited or deteriorated in electrical insulation between them, only the portions connected to the corresponding grounding pads 6 and power supply pads 7 are insulated. It is preferable to form it so as to reach the side surface of the substrate 1.

  In this case, since the width of the grounding pad 6 and the power supply pad 7 is narrow, in order to ensure the electrical connection between the grounding conductor layer 4 and the grounding pad 6 and between the power supply conductor layer 5 and the power supply pad 7. The width of the ground conductor layer 4 and the power conductor layer 5 that reach the side surface of the insulating substrate 1 is preferably at least twice the width of the corresponding ground pad 6 or power pad 7. In consideration of more effectively ensuring the electrical insulation between the power supply pads 7 and the power supply pads 7, it is more preferable to set the number to 2 to 4 times.

  The wiring conductor 3, electrode pad 2, grounding pad 6, and power supply pad 7 should be coated with a plating layer (not shown) of nickel, copper, gold or the like on the exposed surface. In addition to being able to effectively prevent oxidative corrosion, it is possible to further improve the solder connectivity when the electrodes of the electronic component are connected via solder or the like.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

(A), (b) is the side view and sectional drawing which show an example of embodiment of the wiring board of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Insulating substrate 2 ... Electrode pad 3 ... Wiring conductor 4 ... Ground conductor layer 5 ... Power supply conductor layer 6 ... Grounding pad 7 ... Power supply pad

Claims (1)

An insulating substrate having a plurality of insulating layers stacked and having an electronic component mounting portion on the upper surface and side surfaces, and an electrode pad formed on the mounting portion on the upper surface of the insulating substrate and electrically connected to the electronic component A wiring conductor formed from the electrode pad to at least one of a side surface and a lower surface of the insulating substrate, and an end between different layers of the insulating layer so as to reach the mounting portion on the side surface of the insulating substrate. Further , the grounding conductor layer and the power supply conductor layer having a thickness at the outer peripheral portion of the insulating substrate thinner than the thickness at the central portion, and the mounting portion on the side surface of the insulating substrate are formed in contact with the end of the grounding conductor layer A wiring board comprising: a grounding pad; and a power supply pad formed in contact with an end of the power supply conductor layer on the mounting portion on the side surface of the insulating substrate.

Images