JP2010199534A - Substrate for mounting electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for mounting electronic components, provided with electrode pads making it easy to be connected to metal terminals of a convex shape provided in the electronic components on a principal plane of an insulating substrate. <P>SOLUTION: The substrate 9 for mounting electronic components includes: an insulating substrate 1 formed by laminating a plurality of insulating layers composed of glass ceramics; and electrode pads 2 provided on the principal plane of the insulating substrate 1 and connected to electrodes 12 of electronic components 11 through metal terminals 13 of a convex shape. The electrode pad 2 is formed from inside of the insulating substrate 1 to the principal plane, and composed of a through conductor 2b, an end portion thereof projecting from the principal plane, and a metalized layer 2a deposited from the principal plane of the insulating substrate 1 to an outer periphery portion of an end plane of the through conductor 2b, and rising along the outer periphery portion. Since the metalized layer 2a is not deposited on a center portion of the through conductor 2b, a center portion of the electrode pad 2 is prevented from becoming convex, and connection of the metal terminal 13 to the electrode pad 2 can be easily made. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic component mounting substrate in which an electrode pad to which an electrode of an electronic component is connected via a metal terminal is provided on the main surface of an insulating substrate made of glass ceramics.

  As an electronic component mounting substrate on which electronic components such as a semiconductor element, a capacitive element, and a piezoelectric vibrator are mounted, a rectangular plate-like insulating substrate in which a plurality of insulating layers made of glass ceramics are stacked, A device provided with an electrode pad provided on a surface using a metal material such as copper or silver and to which an electrode of an electronic component is electrically connected is often used.

  The electrode pad is made of a metallized layer having a circular pattern or the like attached to the main surface of the insulating substrate, and is formed by penetrating the insulating layer in the thickness direction from the inside of the insulating substrate to the metallized layer of the main surface. A conductor is connected to the metallization layer. Through this through conductor, the electrode of the electronic component that is electrically connected to the metallized layer is electrically connected to a wiring conductor, an external connection pad, or the like disposed on the inside or the bottom surface of the insulating substrate. In general, the through conductor is connected to the metallized layer in a central portion of the metallized layer in a plan view in order to ensure connection to the metallized layer.

  The electrical connection of the electrode of the electronic component to the electrode pad is made of, for example, a metal material such as gold, solder, or aluminum with the electrode pad provided on the main surface of the insulating substrate so as to face the electrode of the electronic component. A convex metal terminal is bonded to the surface of the electrode of the electronic component, and this metal terminal is directly connected to the electrode pad by a bonding method such as ultrasonic pressure bonding.

  Such an electronic component mounting substrate generally has a through hole formed in a ceramic green sheet produced by molding glass powder and ceramic powder into a sheet shape together with an organic solvent and a binder, and the through hole is filled with a metal paste. After that, the metal paste is printed with a predetermined electrode pad pattern on the end face of the filled metal paste and the main surface of the surrounding ceramic green sheet, and then a plurality of ceramic green sheets are laminated and fired. ing. And each ceramic green sheet laminated | stacked and baked becomes each insulating layer which comprises an insulated substrate.

JP 2005-268692 JP 2007-324557 A

  However, in such a substrate for mounting electronic components, the shrinkage ratio during firing differs between the ceramic green sheet serving as the insulating layer constituting the insulating substrate and the metal paste serving as the through conductor (the ceramic green sheet is larger). Therefore, the end of the through conductor tends to protrude outward from the main surface of the insulating substrate during firing. In this case, when the end portion of the penetrating conductor protrudes, the central portion of the metallized layer constituting the electrode pad is deformed into a convex shape accordingly, and the surface of the electrode pad becomes convex. Therefore, there is a possibility that the metal terminal of the electronic component is likely to slip on the surface of the electrode pad, and it is difficult to align and connect the metal terminal and the electrode pad.

  In particular, when the insulating layer is formed of glass ceramic as described above, there is a tendency that the difference in shrinkage rate during firing between the ceramic green sheet and the metal paste tends to be large. Is likely to occur.

  The present invention has been completed in view of the above-described problems of the prior art, and an object of the present invention is to provide an electrode pad on the main surface of an insulating substrate that can be easily connected to a convex metal terminal included in an electronic component. Another object is to provide a substrate for mounting electronic components.

  The electronic component mounting substrate of the present invention is provided on an insulating substrate formed by laminating a plurality of insulating layers made of glass ceramics, and on the main surface of the insulating substrate, and an electrode of the electronic component is interposed through a convex metal terminal. An electronic component mounting substrate comprising an electrode pad to be connected, wherein the electrode pad is formed from the inside of the insulating substrate to the main surface, and an end portion protrudes from the main surface, and the insulation The metallized layer is deposited from the main surface of the substrate to the outer peripheral portion of the end surface of the through conductor and swells along the outer peripheral portion.

  Further, in the electronic component mounting substrate of the present invention, in the above configuration, the through conductor and the metallized layer each contain a glass component, and the glass component content of the through conductor is the glass component content of the metallized layer. It is characterized by more.

  In the electronic component mounting substrate of the present invention, in the above configuration, the through conductor contains a glass component, and the content of the glass component is larger on the central side of the through conductor than on the outer peripheral side. It is a feature.

  According to the electronic component mounting substrate of the present invention, the electrode pad is formed from the inside of the insulating substrate to the main surface, the end portion protrudes from the main surface, and the end surface of the through conductor from the main surface of the insulating substrate. Since it consists of a metallized layer deposited up to the outer peripheral part and rising along the outer peripheral part, the metallized layer constituting the electrode pad is not applied to the central part of the end face of the through conductor, and the center The thickness of the electrode pad can be kept small at the portion. Therefore, in the structure in which the through conductor protrudes outward from the surface of the insulating substrate, it is possible to suppress the central portion of the electrode pad from being convex.

  Further, since the metallized layer is attached to the outer peripheral portion of the end face of the through conductor and is not attached to the central portion of the electrode pad, a concave portion is formed in the central portion according to the thickness of the metalized layer. In addition, since the metal terminal (the tip portion of the metal terminal joined to the electrode of the electronic component) is accommodated in the concave portion, an effect of facilitating the positioning of the metal terminal with respect to the electrode pad can be obtained.

  Therefore, according to the electronic component mounting substrate of the present invention, it is possible to provide an electronic component mounting substrate in which electrode pads that can be easily connected to the convex metal terminals included in the electronic component are provided on the main surface of the insulating substrate. Can do.

  In the electronic component mounting substrate of the present invention, in the above configuration, the through conductor and the metallized layer each contain a glass component, and the glass component content of the through conductor is greater than the glass component content of the metallized layer. Among the through conductors and metallized layers that make up the electrode pad, through the addition of glass components in the through conductors that are surrounded by an insulating layer and that are more susceptible to stresses such as thermal stress with the insulating layer. The effect of reducing the difference in coefficient of thermal expansion with the insulating layer can be further increased. Therefore, for example, defects such as cracks of the through conductor due to thermal stress can be more effectively suppressed, and the reliability of deposition on the insulating substrate as the electrode pad can be increased.

  Further, since the glass component content in the metallized layer having a relatively large connection area with the metal terminal is small, it is effective in increasing the strength of bonding between the metal terminal and the electrode pad, for example, by ultrasonic pressure bonding.

  In the electronic component mounting board of the present invention, in the above configuration, when the through conductor contains a glass component and the content of the glass component is larger than the outer peripheral side at the center side of the through conductor, the through conductor penetrates. For the center side of the conductor, the shrinkage rate during firing of the metal paste that becomes the through conductor by adding the glass component is brought close to the shrinkage rate of the ceramic green sheet, and the end portion of the through conductor is more effectively separated from the main surface of the insulating substrate. Protruding can be suppressed.

  Moreover, since the content of the glass component in the through conductor is small on the outer peripheral side, the electrical resistance as the through conductor can be kept low. In particular, when a high-frequency signal of several MHz or more is transmitted through the through conductor, the signal is transmitted mainly on the outer peripheral side of the through conductor due to the so-called skin effect, so that the glass component is less than the signal transmission. Any obstacles can be effectively suppressed.

(A) is a top view which shows an example of embodiment of the electronic component mounting board | substrate of this invention, (b) is sectional drawing in the AA line. It is a principal part expanded sectional view which expands and shows the principal part of the electronic component mounting board | substrate shown in FIG. (A) And (b) is a principal part expanded sectional view which shows the other example of embodiment of the electronic component mounting board | substrate of this invention, respectively.

  The electronic component mounting board of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1A is a plan view showing an example of an embodiment of an electronic component mounting board according to the present invention, and FIG. 1B is a sectional view taken along line AA in FIG. FIG. 2 is an enlarged cross-sectional view showing an essential part of the electronic component mounting board shown in FIG. In FIGS. 1 and 2, 1 is an insulating substrate, 2 is an electrode pad comprising a metallized layer 2a and a through conductor 2b, and 3 is a wiring conductor. An electronic component mounting substrate 9 is basically constituted by the insulating substrate 1 and the electrode pads 2 provided on the main surface of the insulating substrate 1.

  The insulating substrate 1 is formed by laminating a plurality of insulating layers (no symbol) made of glass ceramics. In the example shown in FIG. 1, the number of insulating layers is four, but other numbers may be used.

  The insulating substrate 1 can be manufactured as follows, for example, when each insulating layer is made of glass ceramics obtained by adding aluminum oxide as a ceramic component to borosilicate glass. That is, a suitable organic binder and an organic solvent are added to and mixed with a raw material powder obtained by adding a ceramic powder such as aluminum oxide to a glass component powder such as silicon oxide or boron oxide, and the mixture is mixed with a doctor blade method or A plurality of ceramic green sheets are obtained by adopting a sheet forming technique such as a lip coater method to form a sheet, and then the ceramic green sheet is formed into an appropriate shape by cutting or punching, and a plurality of these are obtained. The laminated ceramic green sheets are finally laminated and fired at a temperature of about 950 to 1000 ° C. in a reducing atmosphere.

  The insulating substrate 1 has, for example, a rectangular plate shape, functions as a base for mounting and supporting the electronic component 11, and the electronic component 11 is mounted on the main surface (upper surface in the example shown in FIG. 1). Examples of the electronic component 11 include semiconductor integrated circuit elements such as IC and LSI, semiconductor elements including optical semiconductor elements such as LED (light emitting diode), PD (photodiode), and CCD (charge coupled device), surface acoustic wave elements, Various electronic components 11 such as a piezoelectric element such as a crystal resonator, a capacitive element, a resistor, and a micromachine (so-called MEMS element) in which a minute electromechanical mechanism is formed on the surface of a semiconductor substrate can be given.

  On the main surface on which the electronic component 11 of the insulating substrate 1 is mounted, an electrode pad 2 to which the electrode 12 of the electronic component 11 is electrically connected is provided. As shown in FIG. 2, for example, the electrode 12 and the electrode pad 2 are electrically connected by bonding a convex metal terminal 13 made of a metal such as gold, solder, or aluminum to the electrode 12. 13 is directly connected to the electrode pad 2 by a bonding method such as ultrasonic pressure bonding. The metal terminal 13 is bonded to the electrode 12 by a method such as ultrasonic pressure bonding or fusion bonding.

  In the electronic component mounting substrate 9, the electrode pad 2 is formed from the inside of the insulating substrate 1 to the main surface, and the end portion protrudes from the main surface, and the through conductor 2 b extends from the main surface of the insulating substrate 1. It consists of a metallized layer 2a that is deposited up to the outer peripheral portion of the end face and rises along the outer peripheral portion.

  According to such an electronic component mounting substrate 9, since the electrode pad 2 is composed of the through conductor 2b and the metallized layer 2a as described above, the metallized layer 2a constituting the electrode pad 2 is the end surface of the through conductor 2b. Therefore, the thickness of the electrode pad 2 can be kept small at this central portion. Therefore, in the structure in which the through conductor 2b projects outward from the surface of the insulating substrate 1, it is possible to effectively suppress the central portion of the electrode pad 2 from being convex.

  The electrode pad 2 has the metallized layer 2a attached to the outer peripheral portion of the end surface of the through conductor 2b, but the metallized layer 2a is not attached to the center of the end surface of the through conductor 2b. Depending on the thickness, a concave portion (no symbol) is formed at the center. In addition, the metal terminal 13 (the tip portion of the metal terminal 13 or the like) is accommodated in the concave portion, and the effect that the positioning of the metal terminal 13 with respect to the electrode pad 2 is easier and more reliable can be obtained.

  Therefore, according to such an electronic component mounting substrate 9, an electronic component mounting substrate in which the electrode pad 2 that can be easily connected to the convex metal terminal 13 included in the electronic component 11 is provided on the main surface of the insulating substrate 1. A substrate 9 can be provided.

  In such an electrode pad 2, since the metallized layer 2a is raised at the outer peripheral portion of the through conductor 2b, the inner edge of the raised portion can be easily recognized by, for example, an image recognition device. Since the position of the inner edge substantially corresponds to the position of the outer edge of the concave portion, it is easy to align the metal terminal 13 of the electronic component 11 and the electrode pad 2 (particularly the concave portion) by the image recognition device. You can also

  The metallized layer 2a and the through conductor 2b are formed of a metal material such as copper, silver, palladium, gold, or platinum. Since these metal materials, particularly copper and silver, have low electrical resistance, electrical characteristics such as conduction resistance when the electronic component 11 is electrically connected to the electrode pad 2 by suppressing the electrical resistance in the electrode pad 2 low. It is advantageous to make it high. In the electronic component mounting substrate 9 of the present invention, since the insulating substrate 1 is formed by laminating insulating layers made of glass ceramics, the firing temperature when manufacturing the insulating substrate 1 is relatively low as described above. It is easy to form the electrode pad 2 by co-firing with the insulating substrate 1 using a metal material having a relatively low melting point (copper: about 1083 ° C., silver: about 962 ° C.) such as copper or silver.

  The metallized layer 2a has, for example, a circular frame shape, an elliptical ring shape, a polygonal frame shape such as a rectangular frame shape in plan view, and the outer portion is joined to the main surface of the insulating substrate 1, and the inner portion is more than that. The electrode pad 2 for connecting the metal terminal 13 of the electronic component 11 is joined to the end face of the through conductor 2b. For example, when the metal terminal 13 of the electronic component 11 is made of gold or solder, the thickness of the metallized layer 2a may be set to about 10 to 35 μm.

  The through conductor 2b has, for example, a circular shape or an oval shape in the end surface and the cross section, and has a diameter of about 50 to 200 μm. The through conductor 2b constitutes a part of the electrode pad 2, and a conductive path for electrically connecting the electronic component 11 electrically connected to the electrode pad 2 to an external electric circuit (not shown). Part of it.

  That is, the end portion of the through conductor 2b on the main surface side on which the electronic component 11 of the insulating substrate 1 is mounted forms the electrode pad 2 together with the metallized layer 2a, and the other end portion is inside the insulating substrate 1, For example, it connects with the wiring conductor 3 mentioned later. Then, the electronic component 11 electrically connected to the electrode pad 2 is electrically led out to the outer surface such as the side surface and the bottom surface of the insulating substrate 1 through the through conductor 2b and the wiring conductor 3, and this lead portion is externally connected. Connected to the electric circuit, the electronic component 11 and the external electric circuit are electrically connected.

  The through conductor 2b has a through hole (not shown) formed in the ceramic green sheet to be the insulating substrate 1 by a method such as mechanical punching or drilling with a laser beam. By filling a metal paste such as copper, silver, palladium, gold, or platinum by a method such as screen printing, the insulating substrate 1 can be formed. The metal paste is produced by kneading these metal material powders together with an organic solvent and an organic binder. In this case, the through hole needs to be formed at least in a portion of the insulating substrate 1 where the electronic component 11 is mounted.

  Further, the metallized layer 2a is formed by printing and applying a metal paste similar to the above onto the surface of a ceramic green sheet serving as the insulating substrate 1 from the surface to the outer periphery of the metal paste filled in the through holes. be able to. In order to print the metal paste up to the outer periphery of the metal paste filled in the through-holes, for example, the pattern of the printing plate used for screen printing may be a pattern that can be printed in such a range.

  And when these metal pastes are filled and the laminated body of the applied ceramic green sheets is fired, the ceramic green sheet and metal paste shrink due to the difference in shrinkage rate (the ceramic green sheet shrinks more). The ends of the metal paste filled in the holes protrude from the main surface of the insulating substrate 1 (the surface of the ceramic green sheet laminate). Further, the metal paste (metallized layer 2a) applied to this portion rises along the outer peripheral portion of the end portion of the protruding metal paste (through conductor 2b). At this time, the portion along the outer peripheral portion of the through conductor 2b of the metallized layer 2a rises with the protrusion of the through conductor 2b as described above, so that the metal paste that becomes the metallized layer 2a is specially thickened at the outer peripheral portion. It is not necessary to apply so.

  The height at which the through conductor 2b protrudes from the main surface of the insulating substrate 1 as described above is, for example, that the insulating substrate 1 is composed of an insulating layer made of ceramics mainly composed of a borosilicate glass component and aluminum oxide. When the through conductor 2b is made of copper (fired copper metal paste) and has a diameter of about 50 to 200 μm, it is about 6 to 12 μm.

  Further, the height from the end surface of the through conductor 2b of the raised portion of the metallized layer 2a in the outer peripheral part of the through conductor 2b is, for example, about the thickness of the metallized layer 2a (about 10 to 35 μm). .

  As described above, an electrode comprising the through conductor 2b formed from the inside of the insulating substrate 1 to the main surface and the metallized layer 2a deposited from the main surface of the insulating substrate 1 to the outer peripheral portion of the end surface of the through conductor 2b. The pad 2 can be provided on the main surface of the insulating substrate 1.

  The metallized layer 2a is a case where the glass ceramic forming the insulating substrate 1 is mainly composed of borosilicate glass and aluminum oxide, and the through conductor 2b is mainly composed of copper, and the end surface of the through conductor 2b has a diameter of about In the case of a circular shape of about 50 to 200 μm, it may be attached to the outer peripheral portion in a range of about 60% of the entire area of the end face of the through conductor 2b. The metallized layer 2a has an annular shape, an elliptical annular shape, a rectangular frame shape or the like. For example, in the case of an annular shape, the outer diameter is about 200 to 500 μm, and the outer peripheral edge of the end face of the through conductor 2b What is necessary is just to make it adhere with the width | variety of about 5-10 micrometers inside.

  In the example of this embodiment, the wiring conductor 3 is formed from the inside of the insulating substrate 1 to the outer surface. A part of the wiring conductor 3 is located inside the insulating substrate 1 and is electrically connected to the through conductor 2 b, and the other part is located on the outer surface such as a side surface or a lower surface of the insulating substrate 1. For example, the wiring conductor 3 is electrically connected to the electrode 12 of the electronic component 11 via the through conductor 2b, and the portions located on the side surface and the lower surface of the insulating substrate 1 are connected via solder, conductive adhesive, or the like. It is connected to an external electric circuit (not shown) and functions as a conductive path that electrically connects the electronic component 11 and the external electric circuit.

  The wiring conductor 3 is also made of the same metal material as that of the metallized layer 2a and the through conductor 2b, and portions located between the insulating layers and on the lower surface of the insulating substrate 1 are formed on the insulating substrate 1 in the same manner as the metallized layer 2a. The Moreover, the part which penetrates an insulating layer in the thickness direction among the wiring conductors 3 can be formed by the same method as the penetration conductor 2b.

  The connection of the through conductor 2b to the external electric circuit is not limited to the method performed via the wiring conductor 3, but may be a method of directly connecting the through conductor 2b to the external electric circuit. For example, the length of the penetrating conductor 2b is set so as to penetrate the insulating substrate 1 in the thickness direction, and the end surface opposite to that constituting the electrode pad 2 is exposed on the lower surface of the insulating substrate 1, etc. You may make it connect the made end surface to an external electric circuit with a solder, a conductive adhesive, etc.

  In the electronic component mounting substrate 9 of the present invention, the through conductor 2b and the metallized layer 2a each contain a glass component, and the glass component content of the through conductor 2b is the glass component of the metallized layer 2a. In the case where the content is larger than the content, among the through conductor 2b and the metallized layer 2a constituting the electrode pad 2, the periphery is surrounded by the insulating substrate 1 (insulating layer), and stress such as thermal stress is generated between the insulating layer 1 and the insulating layer. In the through conductor 2b that is more likely to act, the effect of reducing the difference in coefficient of thermal expansion from the insulating layer due to the addition of the glass component can be further increased. For this reason, for example, defects such as cracks in the through conductor 2b due to thermal stress can be more effectively suppressed, and the strength of deposition on the insulating substrate 1 as the electrode pad 2 can be increased.

  Further, since the glass component content in the metallized layer 2a having a relatively large connection area with the metal terminal 13 is small, it is effective in increasing the strength of bonding between the metal terminal 13 and the electrode pad 2 by, for example, ultrasonic pressure bonding. It is.

  Further, since the glass component content in the metallized layer 2a having a relatively large connection area with the metal terminal 13 is small, for example, ultrasonic bonding or fusion bonding between the metal terminal 13 and the electrode pad 2 is made stronger. It is effective in doing.

  As the glass component to be added to the metallized layer 2a and the through conductor 2b, the same glass component as the glass component contained in the glass ceramic constituting the insulating layer of the insulating substrate 1 can be used. For example, if the glass ceramic contains a borosilicate glass component, a borosilicate glass or a glass component obtained by adding an alkali metal oxide glass component such as lithium oxide to the borosilicate glass is used. You can do it.

  Further, the amount of the glass component added to the metallized layer 2a and the through conductor 2b may be, for example, about 1 to 4% by mass in the metallized layer 2a and about 2 to 4% by mass in the through conductor 2b.

  Further, in this electronic component mounting board 9, the through conductor 2b contains a glass component (not shown), and the content of the glass component is, for example, as shown in FIGS. 3 (a) and 3 (b). When the center side 2ba of the through conductor 2b is larger than the outer peripheral side 2bb, the shrinkage rate of the ceramic green sheet when the metal paste serving as the through conductor 2b is fired by adding a glass component to the through conductor 2b is reduced. It is possible to suppress the end portion of the through conductor 2b from protruding from the main surface of the insulating substrate 1 more effectively. FIGS. 3A and 3B are enlarged cross-sectional views of main parts showing another example of the embodiment of the electronic component mounting board 9 of the present invention. In FIG. 3, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals.

  Further, since the glass component content is small on the outer peripheral side 2bb of the through conductor 2b, the electrical resistance as the through conductor 2b can be kept low. In particular, when a high-frequency signal of about several MHz or more is transmitted by the through conductor 2b, the signal is transmitted mainly on the outer peripheral side 2bb of the through conductor 2b due to a so-called skin effect. It can also be effectively suppressed that the component becomes an obstacle.

  In this case, the inside of the through conductor 2b has a double (two-layer) structure of a center side 2ba having a relatively large glass component content and a relatively small outer peripheral side 2bb.

  In addition, about the penetration conductor 2b, when increasing content of a glass component by center side 2ba, as shown to Fig.3 (a), center side 2ba to the edge part by the side of the main surface of the insulated substrate 1 of the penetration conductor 2b is shown. However, the structure is not limited to the structure in which the content of the glass component is increased, and for example, a structure as shown in FIG. In the example shown in FIG. 3B, the glass component is reduced in the entire region at the end of the through conductor 2b on the main surface side of the insulating substrate 1 in the same manner as the outer peripheral side 2bb. The example shown in FIG. 3A is advantageous in suppressing the protrusion of the end portion of the through conductor 2b more effectively. In the example shown in FIG. 3B, electric resistance such as contact resistance between the electrode pad 2 constituted by the through conductor 2b and the metal terminal 13 is suppressed while suppressing the protrusion of the end portion of the through conductor 2b. It is advantageous to keep it low.

  As a glass component to be contained in order to suppress such protrusion of the end portion of the through conductor 2b, for example, a glass component similar to the glass component contained in the glass ceramic constituting the insulating layer of the insulating substrate 1 is used. be able to. Further, as the glass component in this case, it is necessary to use glass (amorphous glass) that does not contain a crystal component and is entirely amorphous.

  In particular, in bringing the shrinkage rate of the through conductor 2b (metal paste) close to the shrinkage rate of the insulating substrate 1 (ceramic green sheet), the glass component (amorphous glass) contained in the through conductor 2b is contained in the central side 2ba. The amount may be about 12 to 30% by mass. In addition, the glass component content on the outer peripheral side 2bb of the through conductor 2b is preferably smaller in consideration of the ease of transmission of the high-frequency signal as described above, but there is a difference in content between the central side 2ba and the central conductor 2ba. If it becomes too large, thermal stress may be generated inside the through conductor 2b due to a difference in shrinkage rate or thermal expansion coefficient after firing, and fine cracks may occur. Therefore, the glass component content on the outer peripheral side 2bb of the through conductor 2b is preferably set to about 10 to 20% by mass.

  In order for the through conductor 2b to be composed of the central side 2ba having a large glass component content and the outer peripheral side 2bb having a small glass component content, for example, the content of the glass component serving as the outer peripheral side 2bb of the through conductor 2b is first relatively small. The metal paste is applied to the inner surface of the through hole formed in the ceramic green sheet by a method such as screen printing using vacuum suction, and then the content of the glass component that becomes the central side 2ba of the through conductor 2b is A relatively large amount of metal paste may be filled in the above-described through holes (the vacant portion inside the applied metal paste) and then integrally fired. In addition, after the step of filling a metal paste having a relatively high glass component content, if a metal paste having a relatively small amount of glass component is applied to the surface (exposed end face) of the filled metal paste, A through conductor 2b having a structure as shown in FIG. 3B can be formed.

  The diameter of the through hole and the through conductor 2b in this case is also about 50 to 200 μm as described above, and the diameter of the central side 2ba is, for example, about 25 to 175 μm. In order not to prevent the transmission of a high frequency signal of about several MHz by the through conductor 2b, the outer peripheral side 2bb having a relatively small glass component content is preferably formed into an annular shape having a width of about 25 μm or more. .

  Ceramic green containing about 30% by mass of borosilicate glass component and about 40% by mass of aluminum oxide, and adding raw material powder to which magnesium oxide, calcium oxide, etc. are added to a sheet by the doctor blade method A sheet was prepared, and five layers of this ceramic green sheet were laminated and then fired at 950 ° C. to prepare a square plate-like insulating substrate having a thickness of about 0.6 mm and a side of about 12 mm.

  In the central part of the upper surface (main surface) of this insulating substrate, electrode pads having a diameter of about 150 μm are arranged in an array of 10 × 10 (pieces) with a spacing of 100 μm between each other, and a semiconductor element which is an electronic component The electrode pads provided on the lower surface of the substrate were connected to face each other so that a test electronic component mounting substrate was obtained.

  Here, both the through conductor and the metallized layer constituting each electrode pad were made of copper. The through conductor constituting the electrode pad has a cylindrical shape with a diameter of about 100 μm and continuously penetrates the uppermost layer and the second top layer of the insulating layer in the thickness direction, and the end thereof has a height of about 6 to 10 μm. It was supposed to protrude. In addition, the metallized layer had an annular shape with an outer diameter of about 150 μm, and was applied to the outer peripheral portion of the through conductor with a width of about 10 μm.

The metal paste for forming the through conductor and the metallized layer was prepared by adding a borosilicate glass powder as a glass component to a copper powder having an average particle size of about 5 μm and kneading with an organic solvent and an organic binder. About 5% by mass of borosilicate glass powder as a glass component was added to the metal paste for the through conductor, and about 2% by mass of the same glass powder was added to the metallized layer. The viscosity of the metal paste was adjusted to 190 to 210 Pa · s (measured at a shear rate of 0.1 s ⁻¹ using a rotary viscometer) depending on the amount of binder added.

  Specifically, first, through holes are formed in a ceramic green sheet that is the uppermost layer and the second layer from the top using a mold, and then a metal paste (glass component is about 5 mass by weight) in the through holes. Next, the ceramic green sheets are aligned and laminated so that the through-holes are continuous in the vertical direction, and the metal for the metallization layer in the above pattern is formed on the main surface of the laminate of the ceramic green sheets. The paste (the glass component was about 2% by mass) was printed by screen printing.

  In addition, a wiring conductor is formed using the same metal paste as the through conductor from the portion of the through conductor located inside the insulating substrate (between the second and third layers from the top) to the side surface of the insulating substrate. In this case, the portion of the wiring conductor formed on the side surface of the insulating substrate is used as a measurement terminal so that the electrical connection state between the electrode pad and the electronic component can be confirmed.

  As an electronic component, a semiconductor integrated circuit element in which a convex metal terminal made of a solder ball is bonded to an electrode on the lower surface of a silicon substrate is prepared, and the metal terminal is aligned with an electrode pad using an image recognition device. After that, it was connected by ultrasonic pressure bonding, and the quality of the connected state was confirmed. The quality of the connection state was confirmed by measuring the electrical resistance between the portion of the wiring conductor exposed on the side surface of the insulating substrate and the electrode of the electronic component with a resistance meter.

  Further, as a comparative example, an electronic component mounting board provided with an electrode pad covered with a metallized layer from the main surface of the insulating substrate to the entire end face of the through conductor according to the prior art is the same as described above except for this electrode pad. It produced on condition, and the quality of the connection state was confirmed similarly. Also in this comparative example, the end portion of the through conductor protruded from the main surface of the insulating substrate at a height of about 6 to 10 μm. The number of tests was 100 in both the examples and comparative examples.

  As a result, in the electronic component mounting board according to the example of the present invention, the electrical resistance was about 290 mΩ on the arithmetic average of the plurality of electrode pads, and the connection state was good. On the other hand, in the comparative example, the average electrical resistance was about 290 mΩ, which was about the same as that in the example. However, in the two electronic component mounting substrates, there was a slight misalignment between the metal terminal and the electrode pad. The resulting increase in electrical resistance (about 310 mΩ) was observed.

  In the comparative example, in the electronic component mounting substrate of about 10%, the metal terminal slips on the surface of the electrode pad, and the time required for alignment is about 10 seconds in one electronic component mounting substrate (Example) There was something that took about 10% more.

  As described above, according to the electronic component mounting board of the present invention, it is confirmed that the electrode pad that can be easily connected to the convex metal terminal included in the electronic component can be provided on the main surface of the insulating substrate. We were able to.

DESCRIPTION OF SYMBOLS 1 ... Insulating substrate 2 ... Electrode pad 2a ... Metallization layer 2b ... Through conductor 2ba ... Through conductor central side 2bb ... Through conductor outer periphery 3 ... Wiring conductor 9 ... Electronic component mounting substrate
11 ... Electronic components
12 ... Electrodes
13 ... Metal terminal

Claims (3)

An electronic component comprising: an insulating substrate in which a plurality of insulating layers made of glass ceramics are laminated; and an electrode pad provided on the main surface of the insulating substrate and to which an electrode of the electronic component is connected via a convex metal terminal A mounting substrate, wherein the electrode pad is formed from the inside of the insulating substrate to the main surface, and an end portion protrudes from the main surface, and an end surface of the through conductor from the main surface of the insulating substrate An electronic component mounting board comprising: a metallized layer that is deposited up to the outer periphery of the metal and is raised along the outer periphery. 2. The electronic component mounting according to claim 1, wherein the through conductor and the metallized layer each contain a glass component, and the glass component content of the through conductor is larger than the glass component content of the metallized layer. Substrate. 2. The electronic component mounting substrate according to claim 1, wherein the through conductor contains a glass component, and the content of the glass component is larger at the center side of the through conductor than at the outer peripheral side.

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