JPH11135680A - Electronic component surface mounting board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand the surface area of a board for mounting electronic components by forming a cross-shaped cavity, composed of a recess for mounting a semiconductor element and electrode pad-forming recess having a bottom face higher than that of the element mounting recess. SOLUTION: On an insulation board 11 a cross-shaped cavity 15 for housing a semiconductor element 14 is formed and has a cross shape composed of a rectangular recess 16 for housing this element 14 and electrode pad-forming recess 17 facing opposite crossing that recess 16. A bottom face of the pad- forming recess 17 is higher than that of the element housing recess 16 to result in a min. surface area of the insulation board 11 occupied by the cavity 15 and hence in a max. surface area occupied by electronic components 22, thereby obtaining an electronic components surface mounting board capable of higher density mounting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for mounting electronic components on a surface, and more particularly to a substrate for mounting electronic components on a substrate in which small electronic components such as other chip capacitors are mounted at a high density simultaneously with a semiconductor element. Things.

[0002]

2. Description of the Related Art In recent years, electronic devices have become smaller, lighter and more portable, and the circuit blocks used therein have been reduced in size, weight, and thickness, surface-mounted, and composited in accordance with the trend. .

[0003] In such a trend, ceramic circuit boards have been widely used because of their excellent heat dissipation properties and low dielectric loss, and have been widely applied mainly to hybrid ICs for surface mounting. .

Conventionally, a ceramic circuit board on which a hybrid IC is mounted has generally been a flat plate. However, due to a demand for downsizing of the board, particularly, a reduction in height, an IC chip (semiconductor element) used for this is required. A part of a substrate called a cavity is housed in a recess dug into a square shape.

In recent years, since further reduction in height has been demanded, a first-stage concave portion in which a semiconductor element is arranged, and a lower portion formed around the first-stage concave portion and lower than the bottom of the first-stage concave portion. A second-stage recess having a high bottom surface is formed, and an electrode pad for receiving a wiring for transmitting an electric signal from the semiconductor element is formed in the second-stage recess.

FIGS. 7 and 8 show such a conventional semiconductor device mounting apparatus. 7 is a plan view, and FIG. 8 is a sectional view of FIG. In the drawing, reference numeral 1 indicates an insulating base.
On the surface of the insulating base 1, a first-stage recess 3 for housing the semiconductor element 2 is formed. Around the first-stage recess 3, a second-stage recess 4 is formed in an annular shape. First stage recess 3
A cavity is formed by the second-stage recess 4.

An electrode pad connected to the internal wiring is formed on the surface of the second recess 4, and a wire bonding 6 connected to the semiconductor element 2 is formed on the electrode pad.
Is connected. 7 and 8 on the surface of the insulating substrate 1.
Although not shown, electronic components such as chip capacitors and resistors are mounted. In FIG. 8, the semiconductor element is omitted.

[0008]

However, in the above electronic component surface mounting substrate, a cavity for accommodating the semiconductor element 2 is formed on the surface of the insulating base 1 and the semiconductor element 2 is accommodated in the cavity. Although the height reduction can be promoted, there is a problem that the area of the substrate surface on which various electronic components can be mounted is reduced due to the occupation of the cavity, and the mounting efficiency of the electronic components is reduced.

In particular, in the case of an electronic component surface mounting substrate having a two-stage cavity, the cavity area must be occupied more than the minimum required electrode pad area used for wiring connection. This is because when forming the cavity (second concave portion) of the electrode pad by the conventional tape lamination method, the electrode pad is formed by punching, so that the shape cannot be formed unless it is a simple shape such as a circle and a rectangle. Things.

[0010]

According to the present invention, there is provided a substrate for mounting electronic parts on a surface, comprising: an insulating base formed by laminating a plurality of insulating layers made of ceramics; and a cavity formed in the insulating base for accommodating a semiconductor element. An electronic component surface mounting substrate comprising an electronic component mounted on the insulating substrate surface,
The cavity is a rectangular semiconductor element disposing recess in which a semiconductor element is arranged, and a side extending from an opposite side of the semiconductor element disposing recess toward the end of the insulating base, and shorter than the side. And a pair of electrode pad forming recesses having the following. In the insulating layer made of the ceramic of the present invention, the ceramic includes glass ceramics.

[0011]

According to the electronic component surface mounting substrate of the present invention, the electronic component surface mounting substrate includes a semiconductor element arranging concave portion for arranging a semiconductor element and an electrode pad forming concave portion formed on an opposite side of the semiconductor element arranging concave portion. Since the cross-shaped cavity is formed, the surface area of the base on which electronic components such as capacitors are mounted can be greatly increased.

That is, the present invention provides an electronic component surface in which a cavity is formed in two steps, and a lower part is a fixing part of a semiconductor element, and an upper part is a part for forming an electrode pad used for connection between the semiconductor element and an insulating base. Although it is a mounting substrate, since the upper cavity shape is a cross shape, the area of the electrode pad can be reduced to the minimum necessary, the ratio of the cavity on the surface of the insulating substrate is minimized, and electronic components are mounted. The ratio of the possible surface area is maximized, and it is possible to provide an electronic component surface mounting substrate capable of mounting at a higher density.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a substrate for surface mounting electronic parts according to the present invention. In FIG. 1, reference numeral 11 indicates an insulating base. As shown in FIG. 2, this insulating base 11 is formed by laminating four insulating layers 11a to 11d made of ceramic or glass ceramic, and an internal wiring is provided between these insulating layers 11a to 11d. 12 and via-hole conductors 13 are formed.

As shown in FIG. 3, a cross-shaped cavity 1 for accommodating a semiconductor element 14 is provided in the insulating base 11.
5 are formed. As shown in FIGS. 4 and 5, the cavity 15 has a rectangular semiconductor element disposing recess 16 for housing and disposing the semiconductor element 14, and an electrode pad formed at a position facing the semiconductor element disposing recess 16. The concave portion 17 for forming an electrode pad is formed to have a cross shape, and the bottom surface of the concave portion 17 for forming an electrode pad is formed higher than the bottom surface of the concave portion 16 for placing a semiconductor element.

That is, the cavity 15 is
Are arranged to extend from the opposing sides of the semiconductor element disposing recess 16 toward the end of the insulating base 11, and the opposing sides of the conductive element disposing recess 16 are arranged. And a pair of electrode pad forming recesses 17 having shorter sides.

An electrode pad 19 for wire bonding connected to the internal wiring 12 is formed on the bottom surface of the recess 17 for forming an electrode pad. As shown in FIG. The semiconductor element 14 fixed to the bottom surface of the semiconductor device 16 is connected by wire bonding 20. The area of the bottom surface of the electrode pad forming concave portion 17 in which the electrode pad 19 is formed may be a minimum area required for wire bonding. That is, the area and shape of the electrode pad forming recess 17 can be made smaller than the size of the semiconductor element 14. In addition, as long as wire bonding is possible, a more complicated arbitrary shape can be used.

As shown in FIG. 1, a surface wiring 21 is formed on the surface of the insulating substrate 11 other than the portion where the cross-shaped cavity 15 is formed.
, An electronic component 22 such as a chip capacitor or a resistor is mounted. Terminals such as an input / output terminal, a power supply terminal, and a ground terminal are shown as end surface electrodes 23 on the side surface of the insulating base 11.

In FIG. 2, electronic components formed on the surface of the insulating base 11 are omitted for easy understanding. In FIG. 3, the electronic components and the surface wiring are omitted, and in FIGS. 4 and 5, the semiconductor element, the electronic component and the surface wiring are omitted.

The method for manufacturing a surface mounting board for electronic parts according to the present invention is directed to a surface mounting board for electronic parts having a plurality of insulating layers made of ceramics and a cavity on the surface for mounting a semiconductor element. , Which is manufactured by a method including the following steps (a) to (e).

(A) an insulating layer material made of ceramics,
Step (b) of forming a slip material containing a photocurable monomer and an organic binder; (b) thinning and drying the slip material to form an insulating layer molded product; and (c) subjecting the insulating layer molded product to exposure treatment. Step of applying and curing (b) Applying (b)
The step (c) is sequentially repeated to produce a laminated molded article in which a plurality of insulating layer molded articles are laminated, and the insulating layer molded article obtained in the step (b) is subjected to exposure and development processing to form a semiconductor element arrangement. Form a through-hole at the position where the recess is formed, fill the through-hole with a photo-curable or thermo-curable resin paste,
After the curing step, the slip material is thinned and dried to form an insulating layer molded body, a through hole is formed at a position where a concave portion for forming an electrode pad and a concave portion for forming a semiconductor element are formed,
A step of filling the through-hole with the resin paste and curing to form a laminated molded body having a cavity filled with the resin paste; and (e) a step of firing the laminated molded body. Although the formation of the conductor is omitted, it is necessary to form the conductor as needed. For the internal wiring, a conductive paste is applied to the insulating layer molded body after the exposure processing, and for the via hole conductor, the slip is thinned, and the dried insulating layer molded body is exposed and developed at the via hole forming position. A via hole can be formed by forming a through hole and filling the through hole with a conductive paste.

The method of manufacturing the electronic component surface mounting board of the present invention will be specifically described. First, the slip material serving as the insulating layer is a solvent-based slip material obtained by homogeneously kneading a glass ceramic or ceramic material, a photocurable monomer, an organic binder, and an organic solvent.

When a so-called low-temperature fired ceramic fired at 850 to 1050 ° C. is used as a composite circuit block, a ceramic material and a glass material (both are called solid components) are generally used for the insulating layer. .

The slip material is, for example, 70% by weight of a crystallized glass powder mainly composed of glass materials SiO ₂ , Al ₂ O ₃ , ZnO, MgO and B ₂ O ₃ and 30% by weight of alumina powder as a ceramic material % Of a ceramic raw material powder, and a photocurable monomer such as polyoxyethylated trimethylolpropane triacrylate,
An organic binder, for example, an alkyl methacrylate, and a plasticizer are mixed with an organic solvent, for example, ethyl carbitol acetate, and kneaded in a ball mill for about 48 hours.

In the above embodiment, a solvent-based slip material is prepared. However, as described above, a photocurable monomer having a hydrophilic functional group added thereto, for example, a polyfunctional methacrylate monomer, an organic binder, for example, An aqueous slip material kneaded with ion-exchanged water may be prepared by using a carboxyl-modified alkyl methacrylate.

The ceramic raw material powder is a composite oxide containing at least Mg, Ti, and Ca as metal elements.
x) MgTiO ₃ -xCaTiO ₃ (where x represents a weight ratio and 0.01 ≦ x ≦ 0.15), and 100 parts by weight of the main component represented by B ₂ O ₃ 3 to 30 parts by weight in terms of conversion, and 1 to 25 parts by weight of an alkali metal-containing compound in terms of alkali metal carbonate may be added.

The internal wiring 12 and the via-hole conductor 13
A conductive paste is prepared.

The conductive paste is a metal material having a low melting point and low resistance, such as silver powder, and a borosilicate low melting point glass, such as B ₂ O ₃ —SiO ₂ —BaO glass, CaO
-B ₂ O ₃ -SiO ₂ glass, CaO-Al ₂ O ₃ -B
₂ O ₃ —SiO ₂ glass and an organic binder, for example, ethyl cellulose, are mixed with an organic solvent, for example, 2,2,4-trimethyl-1,3-pentadiol monoisobutyrate, and homogenously kneaded with three rollers. Created.

The conductive paste of the conductive material to be the surface wiring 21 is obtained by homogeneously kneading a powder of at least one metal material of a silver alloy or copper, a low-melting glass component, an organic binder and an organic solvent. Are preferably used. The conductive paste of the conductor material to be the internal wiring and via-hole conductor may be the same as that of the surface wiring,
A material containing silver as a main component may be used. Since these materials have a firing temperature of 850 to 1050 ° C. in particular, a metal material having a relatively low melting point and a low resistance material is selected. Taking into account the sintering behavior with a body (one coated with a slip material and dried), one having a deformation point of about 700 ° C. is used.

Next, as shown in FIG. 6A, a conductive paste for forming the above-mentioned surface wiring 21 is applied to the surface of the support substrate 24 and dried to form a conductive member 25. Thereafter, the above-mentioned slip material is applied so as to cover the above-mentioned conductive member 25 and dried to form the lowermost insulating layer molded body 26a. Specifically, first, the conductive member 25 of the support substrate 24
The above-mentioned slip material is applied thereon by a doctor blade method and then dried to form an insulating layer molded body 26a to be the lowermost insulating layer 11a of the fired insulating layers 11a to 11d.

Here, a mylar film is used as the support substrate 24, which is removed before the firing step. Drying conditions after the application are drying at 60 to 80 ° C. for 20 minutes, and the thickness of the thinned and dried insulating layer molded body 26a is 120 μm.

Since the peer-hole conductor 13 is formed in the insulating layer 11a, as shown in FIG. 6B, a via hole is formed in the insulating layer molded body 26a by exposure and development.

In the exposure process, for example, a photo target is brought close to or placed on the insulating layer molded body 26a, and a region other than the position where a via hole is formed is irradiated with exposure light of a low-pressure, high-pressure, or ultra-high pressure mercury lamp. I do. As a result, in a region other than the via hole, the photocurable monomer causes a photopolymerization reaction. Therefore, only the via hole portion becomes a solubilized portion that can be removed by the development processing.

Specifically, the exposure treatment is performed on the insulating layer molded body 2
6a, a photo target is placed such that a region where a via hole is to be formed is shielded from light, and an ultra-high pressure mercury lamp (10 m
(W / cm ² ) as a light source.

As a result, the photopolymerization reaction of the photocurable monomer does not occur in the insulating layer molded body 26a in the region where the via hole is formed, and the light is not cured in the insulating layer molded body 26a other than the region where the via hole is formed. A polymerization reaction occurs. Here, the part where the photopolymerization reaction has occurred is called an insolubilized part, and the part where the photopolymerization reaction does not occur is called a solubilized part. still,
An insulating layer molded body having a thickness of about 120 μm is formed of an ultra-high pressure mercury lamp
mW / cm ² ) for about 20 to 30 seconds, the exposure can be performed.

In the developing treatment, a solvent such as chlorocene is brought into contact with the exposed and solubilized portion as the insulating layer molded body 26a by, for example, a spray developing method or a paddle developing method to perform development. Thereafter, washing and drying are performed as necessary. The development process is
This is for removing the solubilized portion of the insulating layer molded body 26a with a developing solution. Specifically, 1,1,1-trichloroethane is developed by a spray method.

By this developing treatment, the insulating layer molded body 26a
In the case of a via hole, a through hole having a diameter of 100 to 200 μm can be formed. After that, unnecessary debris or the like generated by developing the insulating layer molded body 26a is washed,
It is completely removed by a drying step.

Next, the conductive paste is filled in the through holes for via holes and dried. Specifically, the conductive paste is filled in the through-hole for a via hole formed in the above-described process, and dried. The conductive member 27 to be the via-hole conductor 13 is formed by printing using a screen that can be printed only on the portion corresponding to the via-hole through-hole.
Dry at 0 ° C for 10 minutes.

Next, a pattern to be the internal wiring 12 is printed and dried. Specifically, as shown in FIG. 6B, an internal wiring pattern 28 that is to be the internal wiring 12 disposed between the insulating layer 10a and the insulating layer 10b is formed by a screen printing method, and dried. .

Then, the steps from the formation of the insulating layer molded body 26a to the formation of the internal wiring pattern 28 are repeated. In this way, as shown in FIG. 6C, the insulating layer molded body 26b is laminated, and the conductive member 27 and the internal wiring pattern 28 are formed.

Thereafter, as shown in FIG. 6D, an insulating layer formed body 26c is formed on the surface of the insulating layer formed body 26b, and a through hole serving as a via hole and a recess 16 for arranging semiconductor elements are formed by exposure and development processing. Opening 30 is formed. Thereafter, a conductive paste is filled into the through-hole serving as a via hole, and a thermosetting resin or a photocurable resin is filled into the opening 30 and cured.

Thereafter, as shown in FIG. 6E, an insulating layer formed body 26d is formed on the surface of the insulating layer formed body 26c and on the surface of the opening 30, and through holes and electrodes serving as via holes are formed by exposure and development processing. An opening 33 to be the pad forming recess 17 and the semiconductor element disposing recess 16 is formed. Thereafter, a conductive paste is filled into the through-holes serving as via holes, and a resin 31 made of a thermosetting resin or a photo-setting resin is filled into the openings 33 and cured.

Then, a conductive paste to be the surface wiring 21 is applied to the surface of the insulating layer formed body 26d, and dried to produce a laminated formed body.

Next, if necessary, the shape of the laminated molded product is adjusted by pressing, a dividing groove is formed, and the support substrate 24 is removed.

Next, firing is performed. The firing includes a binder removing step and a main firing step. The binder removal process is roughly 6
The temperature range is not higher than 00 ° C.
6d, internal wiring pattern 28, organic binder contained in conductive member 27, photo-curable monomer, opening 3
This is a process of erasing the resin 31 filled in 0, 33,
The main baking process is a baking process with a peak temperature of 850 to 1050 ° C., for example, a peak of 900 ° C. for 30 minutes. By firing the conductive member 27 collectively, the electronic component surface mounting substrate of the present invention is manufactured.

Thereafter, as a surface treatment, printing and baking of a thick-film resistive film and a thick-film protective film, plating, and bonding of electronic components including semiconductor elements are further performed. After that, by dividing the substrate along the dividing grooves, the electronic component surface mounting substrate as shown in FIG. 1 is obtained.

According to the electronic component surface mounting substrate of the present invention, the semiconductor element disposing recess 1 in which the semiconductor element 14 is disposed
6 and the concave portion 17 for forming an electrode pad having a bottom surface higher than the bottom surface of the concave portion 16 for arranging the semiconductor element, the cross-shaped cavity 15 is formed, so that the proportion of the cavity 15 on the surface of the insulating substrate 11 is minimized. In addition, the ratio of the surface area on which the electronic component 22 can be mounted is maximized, and it is possible to provide an electronic component surface mounting substrate that can be mounted at a higher density. That is, in the related art, the cavity shown by the one-dot chain line in FIG. 3 was necessary, but in the present invention, the cavity can be made smaller as shown by the solid line.

Further, according to the above-described manufacturing method, the via holes and the through-holes for the cavities are formed by exposure and development using a photo target. The present invention has a cross-shaped cavity having a shape that cannot be obtained by a conventional manufacturing method, that is, punching of a mold or an NC punch, and having high relative positional accuracy. A substrate for electronic component surface mounting can be easily manufactured.

Furthermore, since the insulating layer molded body is formed by applying the slip material to be the insulating layer, the surface of the insulating layer molded body can always maintain a flat state regardless of the lamination state of the wiring pattern of the internal wiring. In forming the wiring pattern on the insulating layer molded body, the accuracy becomes extremely high.

In the above embodiment, the internal wiring 12 is
The method of manufacturing a low-temperature sintering ceramic substrate using Au-based, Ag-based, and Cu-based low-melting metal materials has been described. The manufacturing method of the present invention may be applied to a ceramic substrate fired in the above.
In this case, it is necessary to set the composition of the glass material of the slip material as a predetermined component, and further set the mixing ratio with the ceramic material to a predetermined value.

[0050]

According to the present invention, a cross-shaped cavity comprising a semiconductor element disposing recess for disposing a semiconductor element and an electrode pad forming recess having a bottom surface higher than the bottom surface of the semiconductor element disposing recess is formed. As a result, the surface area of the substrate on which electronic components such as capacitors are mounted can be greatly increased.

[Brief description of the drawings]

FIG. 1 is a perspective view in which a semiconductor element is mounted on an electronic component surface mounting substrate of the present invention.

FIG. 2 is a sectional view of FIG.

FIG. 3 is a plan view of FIG. 1;

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a sectional view taken along the line BB in FIG. 3;

FIG. 6 is a process chart for explaining the method for manufacturing an electronic component surface mounting board of the present invention.

FIG. 7 is a perspective view in which a semiconductor element is mounted on a conventional electronic component surface mounting substrate.

FIG. 8 is a sectional view taken along line CC of FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Insulating base 11a-11d ... Insulating layer 12 ... Internal wiring 13 ... Via-hole conductor 14 ... Semiconductor element 15 ... Cavity 16 ... Semiconductor element arrangement recessed part 17 ... Electrode pad forming recess 19: electrode pad 20: wire bonding 22: electronic component

Continuing from the front page (72) Inventor Michinobu Nakamiya 1-4 Yamashita-cho, Kokubu-shi, Kagoshima Inside the Kyocera Research Institute (72) Inventor Shin-ichi Enami 1-4-1 Yamashita-cho, Kokubu-shi, Kagoshima Kyocera Corporation Inside the company research institute

Claims (1)

[Claims] An electronic device comprising: an insulating base formed by laminating a plurality of insulating layers made of ceramics; and a cavity formed in the insulating base for accommodating a semiconductor element, wherein an electronic component is mounted on the surface of the insulating base. In the component surface mounting board,
The cavity is a rectangular semiconductor element disposing recess in which a semiconductor element is arranged, and a side extending from an opposite side of the semiconductor element disposing recess toward the end of the insulating base, and shorter than the side. And a pair of concave portions for forming an electrode pad, comprising: a substrate for mounting electronic components;