JP2007173616A - Substrate for mounting electronic component and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for mounting an electronic component and an electronic device with an electrical short circuit between electrodes of the electronic component and electrode pads effectively prevented even for the downsized and highly densely packaged susbtrate and electronic device. <P>SOLUTION: The substrate 10 for mounting the electronic component comprises a mounting part 12 for mounting the electronic component 20 by brazing, and electrode pads 30 arranged at the mounting part 12 corresponding to each electrode 21 of the electronic component 20. An insulating layer 40 positioning between the adjacent electrode pads 30 at the mounting part 12 is provided, and the layer 40 and a substrate 11 are made of the same material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic component mounting board and an electronic device for mounting electronic components such as capacitors and chip resistors.

  Conventionally, as an electronic component mounting board for mounting electronic components such as capacitors and chip resistors, an aluminum oxide sintered body, a glass ceramic sintered body, an organic resin such as an epoxy resin or a polyimide resin, or a ceramic powder This is a structure in which a mounting portion including an electrode pad to which an electrode of an electronic component is connected is provided on a substrate made of an electrically insulating material such as a composite material with an organic resin.

  An electronic device is formed by mounting an electronic component on the mounting portion of the electronic component mounting substrate and electrically connecting an electrode of the electronic component and an electrode pad on the substrate. This electronic device is mounted and electronically connected by electrically and mechanically connecting the lead-out portion of the wiring conductor to an external electric circuit via a conductive connecting material such as solder or conductive adhesive. The component is electrically connected to an external electric circuit.

  However, electronic parts have been formed with a plurality of electrodes having a narrower adjacent interval in accordance with downsizing and higher integration. In addition, in response to an increase in the number of electronic components mounted on an electronic component mounting board and a demand for downsizing of an electronic device, a plurality of electronic components are mounted on an electronic component mounting board with a narrower interval (so-called). High-density mounting).

  Therefore, in the electronic component mounting substrate, there is a tendency that the adjacent distance between the electrode pads tends to be narrow, and the electrodes and the electrode pads are easily short-circuited electrically via a connecting material that is accidentally spread or spread. Is starting to occur.

  In particular, tin-silver solder or the like that does not contain lead (so-called lead-free solder) is often used as a connecting material. In this case, the temperature of bonding (soldering) of lead-free solder is conventional tin-lead. Since it is higher than eutectic solder, it tends to spread at the time of bonding, and the occurrence of an electrical short circuit between the electrodes and electrode pads becomes remarkable.

Therefore, in recent years, a solder restricting layer made of resin is formed around the electrode pad on which the electronic component is mounted in the mounting portion where the electronic component is mounted, thereby minimizing the flow of solder when joining the electronic component by soldering. A method such as pressing to the limit is taken.
JP 2004-14964 A Japanese Patent Laid-Open No. 7-176859 JP 2003-133713 A

  However, in the case of the method of suppressing the flow of solder by providing the solder regulation layer made of resin as described above, the substrate is formed by heating the solder when soldering the electrode in the electronic component and the electrode pad on the substrate. Due to the difference in coefficient of thermal expansion between the ceramic sintered body and organic resin material and the resin forming the solder control layer, thermal stress occurs between them, making the solder control layer easy to deform and peel However, the molten solder flow cannot be sufficiently suppressed.

  The present invention has been devised in view of the above-described problems, and its purpose is to effectively prevent electrical shorting between electrodes and electrode pads of electronic components even in the case of miniaturization and high-density mounting. Another object of the present invention is to provide an electronic component mounting substrate and an electronic device.

  An electronic component mounting board according to the present invention includes an electronic component mounting including a mounting portion for mounting the electronic component by soldering, and an electrode pad arranged corresponding to each electrode of the electronic component in the mounting portion. It is a board | substrate, Comprising: While providing the insulating layer located between the electrode pads adjacent in the said mounting part, the said insulating layer and a board | substrate are formed from the same material, It is characterized by the above-mentioned.

  The insulating layer and the substrate are made of an aluminum oxide sintered body.

  Further, the insulating layer has a thickness larger than that of the electrode pad.

  Furthermore, the insulating layer extends over the entire length between the adjacent electrode pads.

  The electronic device of the present invention includes the electronic component mounting substrate, an electronic component having a plurality of electrodes and mounted on the mounting portion, the electrode pad of the electronic component mounting substrate, and the electrode of the electronic component. And a solder for electrically connecting the electrode pad and the electrode. The electrode pad and the electrode are electrically connected to each other.

  Furthermore, the insulating layer is in contact with a portion located between adjacent electrodes on the surface where each electrode is formed in the electronic component.

  According to the electronic component mounting substrate of the present invention, since the insulating layer is provided between the adjacent electrode pads in the mounting portion, and since the insulating layer and the substrate are formed of the same material, the electrode and the electrode pad Since the solder connecting the two electrodes is blocked by the insulating layer, it is possible to prevent the solder from flowing between adjacent electrodes and electrode pads. As a result, a plurality of electrodes and electrode pads are formed with a narrow adjacent interval. Even so, an electrical short circuit through the solder between the electrodes and electrode pads can be more reliably prevented. In addition, since the insulating layer and the substrate are made of the same material, even if heat is applied during soldering, the thermal stress between the two caused by this heat can be suppressed, so the adhesion strength of the insulating layer Even if it is connected using the lead-free solder, the flow of solder is sufficiently suppressed, and the insulating layer is located between adjacent electrode pads in the mounting portion, so that the substrate itself is downsized. In addition, when an electronic device is mounted with an electronic component, by mounting the electronic component on the insulating layer, stable mounting can be achieved, and at the same time, a positioning action can be achieved. Therefore, even in the case of downsizing or high-density mounting, it is possible to effectively prevent an electrical short circuit between the electrodes and electrode pads of the electronic component.

  The electronic device of the present invention includes the electronic component mounting substrate, an electronic component having a plurality of electrodes and mounted on the mounting portion, the electrode pad of the electronic component mounting substrate, and the electronic component. And at least a part of the electrode pad and the brazing material for electrically connecting the electrode pad and the electrode. A short circuit with the electrode pad can be prevented.

  In the electronic device of the present invention, since the insulating layer is in contact with a portion located between adjacent electrodes on the surface of each electrode in the electronic component, the electronic component can be stably mounted on the insulating layer. In addition, it can function as a position when the electronic parts are joined. Therefore, it is possible to provide an electronic device that can prevent an electrical short circuit between electrodes and electrode pads of an electronic component even in the case of downsizing or high-density mounting.

  Hereinafter, the best mode of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an example of an embodiment of an electronic component mounting board 10 of the present invention and an electronic device X on which an electronic component is mounted. (A) is a sectional view in the thickness direction of the substrate, and (b) is a plan view. It is. In FIG. 1, 20 is an electronic component having an electrode 21, 11 is a substrate, 12 is a mounting portion for mounting the electronic component 20, 30 is an electrode pad, and 40 is an insulating layer.

  The mounting part 12, the electrode pad 30, and the insulating layer 40 are disposed on a substrate 11 formed of, for example, an electrically insulating material, so that the electronic component mounting substrate 10 is basically formed. In addition, the electronic device 20 is basically formed by mounting the electronic component 20 on the mounting portion 12 and electrically connecting the electrode 21 of the electronic component 20 to the electrode pad 30 via the solder 50.

  In the electronic component mounting substrate 10 of the present invention, the substrate 11 is a ceramic such as an aluminum oxide sintered body, a glass ceramic sintered body, an aluminum nitride sintered body, a mullite sintered body, or a silicon nitride sintered body. It is made of a resin material such as a sintered body, an epoxy resin or a polyimide resin, or an electrically insulating material such as a composite material obtained by bonding an inorganic powder such as aluminum oxide with an organic resin such as an epoxy resin.

  For example, when the substrate 11 is made of an aluminum oxide sintered body, the substrate 11 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 mud-like ceramic slurry. A ceramic green sheet (a ceramic raw sheet, hereinafter also referred to as a green sheet) is obtained by forming a sheet by employing a sheet forming technique. Thereafter, green sheets are laminated in a predetermined order to form a green ceramic molded body. The raw ceramic molded body is fired at a high temperature of about 1300 to 1600 ° C. in a reducing atmosphere, thereby producing the substrate 11.

  In this embodiment, the electronic component 20 mounting portion 12 is provided on the upper surface of the substrate 11, and the electronic component 20 to be mounted is a capacitor, a chip resistor, an inductor, or the like.

  If the electronic component 20 is a capacitor (chip-shaped ceramic capacitor), for example, a large number of dielectric layers (not shown) made of a ceramic material such as barium titanate are stacked with a conductor serving as a capacitive electrode interposed therebetween. The conductor layer (not shown) used as a pair of electrodes 21 was adhere | attached on the edge part and side surface of the upper and lower surfaces of a rectangular parallelepiped base | substrate.

  A plurality of electrode pads 30 are formed on the mounting portion 12 on which the electronic component 20 formed on the main surface of the substrate 11 is mounted. The electrode pad 30 functions as a connection conductor for electrically connecting to the electrode 21 of the electronic component 20 mounted on the mounting portion 12, and in order to make the connection with the electrode 21 easy and reliable, The electrode pad 30 is disposed corresponding to the electrode of the electronic component 20. For example, when the electronic component 20 is a chip capacitor having a pair of electrodes at both ends of the lower surface of a rectangular parallelepiped base, the electrode pad 30 is formed in a pair of rectangular patterns.

  The electrode 21 and the electrode pad 30 of the electronic component 20 are electrically connected via a brazing material such as conductive solder 50. Solder 50 is composed of tin-lead (eutectic) solder, tin-silver, tin-silver-copper, tin-silver-copper-bismuth, tin-silver-copper-zinc, etc. A brazing material such as gold-silicon or gold-germanium is used.

  This electrical connection is performed as follows, for example, when the connecting material is tin-silver solder. That is, first, when the electronic component 20 is mounted on the mounting portion 12, the electrode 21 on the lower surface of the electronic component 20 is aligned with the electrode pad 30 via the solder 50. Next, the solder 50 is heated and melted, and cooled and cured. As described above, the electrode 21 and the electrode pad 30 are electrically connected via the solder 50. The solder 50 is interposed between the electrode 21 and the electrode pad 30 by, for example, printing and applying a tin-silver solder paste on the surface of the electrode pad 30 before alignment. Can do.

  Here, the electronic component mounting board of the present invention includes the insulating layer 40 between the adjacent electrode pads 30 in the mounting portion 12, and the insulating layer 40 and the substrate 11 are formed of the same material. is important.

  Since the insulating layer 40 is provided so as to be positioned between the adjacent electrode pads 30 in the mounting portion 12, the solder 50 that connects the electrode 21 and the electrode pad 30 is blocked by the insulating layer 40, so that the adjacent electrode 21. Further, it is possible to prevent the electrode pads 30 from spreading so as to connect each other. Therefore, the electrical short circuit between the electrodes 21 and the electrode pads 30 via the solder 50 is formed when the plurality of electrodes 21 and the electrode pads 30 are formed with a narrow interval between adjacent electrodes, that is, the electronic device is reduced in size and density. Even in the case of mounting, an electrical short circuit between the electrode 21 and the electrode pad 30 of the electronic component 20 can be effectively prevented. In addition, since the insulating layer 40 is formed of the same material as the substrate 11, even when heat is applied during soldering, the thermal stress between the insulating layer 40 and the substrate 11 caused by this heat is generated. Since the adhesion strength of the insulating layer 40 is high and the solder 50 is connected using lead-free solder, which has been widely used in recent years, the flow of the solder 50 can be sufficiently suppressed.

  The insulating layer 40 and the substrate 11 may be made of the same material as long as the main components of the respective materials are the same. However, the insulating layer 40 takes into account the strength of bonding to the substrate 11, productivity, and the like. More preferably, it is formed of a material having the same composition as the material forming the substrate 11.

  In particular, the insulating layer 40 and the substrate 11 are preferably made of an aluminum oxide sintered body, are excellent in electrical insulation, and have good bonding properties with the electrode pad 30. Therefore, the insulating layer 40 and the substrate 11 are preferably used as the substrate 11. Can do. In addition, when the insulating layer 40 is formed on the substrate 11, for example, an organic solvent, a binder, or the like is added to the aluminum oxide raw material powder having the same composition as the aluminum oxide green sheet forming the substrate 11 and kneaded. The ceramic paste produced by making the paste can be easily formed by printing and firing so as to be positioned between the adjacent electrode pads 30 in the mounting portion 12. Further, since the ceramic paste made of aluminum oxide can be printed and formed, the insulating layer 40 can be formed with high accuracy even when the distance between the electrode pads 30 is very small.

  The insulating layer 40 preferably has a thickness T1 greater than a thickness T2 of the electrode pad 30. Thereby, the opposing surface 22 which opposes the mounting part 12 in the electronic component 20 can be stably mounted on the insulating layer 40, and at the same time, a positioning action can be achieved. In addition, the flow of the solder 50 can be more reliably blocked between the plurality of electrodes 21 and the electrode pads 30 of the electronic component 20.

  The difference between the thickness of the insulating layer 40 and the sum of the protruding height of the electrode 21 from the surface 22 facing the mounting portion 12 of the electronic component 20 and the thickness of the electrode pad 30 is, for example, the electrode 21 and the electrode pad. This corresponds to the thickness of the solder 50 interposed between the solder and the solder.

  The insulating layer 40 preferably extends over the longitudinal direction between the adjacent electrode pads 30. The insulating layer 40 is formed in the longitudinal direction between the electrode pads 30, that is, over the entire facing portion 13, and can prevent the solder 50 from flowing and spreading so as to connect between the electrode pads 30. The flow of the solder 50 can be more reliably blocked between the plurality of 20 electrodes 21 and the electrode pads 30. For example, when the electronic component 20 is a ceramic capacitor, the electrodes 21 are located at both ends on the short side including the lower surface side of the rectangular parallelepiped base (not indicated) of the electronic component 20 formed of ceramics. The layer 40 is formed in the central part of the electronic component 20 in plan view along a rectangular region connecting both ends on the long side.

  Next, the electronic device of the present invention will be described.

  The electronic device X of the present invention includes an electronic component mounting substrate 10, an electronic component 20 having a plurality of electrodes 21 and mounted on the mounting portion 12, the electrode pad 30 of the electronic component mounting substrate 10, and the At least a portion is interposed between the electrode 21 of the electronic component 20 and the electrode pad 30 and the solder 50 for electrically connecting the electrode 21 are provided.

  As described above, the electronic component 20 is a capacitor such as a ceramic capacitor, a chip resistor, an inductor, or the like, and sealing means (such as a lid or a sealing resin) as necessary to prevent oxidative corrosion of the electrode 21 or the like. (Not shown).

  The entire amount of the solder 50 is not necessarily interposed between the electrode 21 and the electrode pad 30. For example, in the case of a chip capacitor, since the electrode 21 extends to the side surface of the electronic component, the solder 50 is joined so as to extend from between the electrode 21 and the electrode pad 30 to the side surface of the electronic component 20. Has been. A brazing material other than the solder 50 may be used.

  According to such an electronic device X, since the mounting layer 12 includes the insulating layer 40 located between the adjacent electrode pads 30, the electrode 21 and the electrode pad 30 are electrically short-circuited via the solder 50. This can be effectively prevented by the insulating layer 40.

  Therefore, even in the case of downsizing or high-density mounting, it is possible to provide the electronic device X in which an electrical short circuit between the electrode 21 and the electrode pad 30 of the electronic component 20 is effectively prevented.

  In the electronic device X, the insulating layer 40 is preferably in contact with a portion located between the adjacent electrodes 21 on the formation surface 22 of each electrode 21 in the electronic component 20. In this case, spreading of the solder 50 so as to connect the electrodes 21 is more effectively suppressed. Therefore, the electronic device X in which an electrical short circuit between the electrode 21 and the electrode pad 30 of the electronic component 20 is more effectively prevented can be obtained.

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

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of embodiment of the electronic component mounting board | substrate and electronic device of this invention, (a) is sectional drawing in the thickness direction of a board | substrate, (b) is a top view.

Explanation of symbols

10 .... Electronic component mounting board 11 .... Board 12 .... Mounting part 13 .... Counter part 20 .... Electronic component 21 ... Electrode 22 .... Opposite surface 30 ... Electrode pad 40 ... Insulating layer 50 ... Solder X ... Electronic device

Claims (6)

An electronic component mounting board comprising: a mounting portion for mounting an electronic component by brazing; and an electrode pad disposed corresponding to each electrode of the electronic component in the mounting portion, An electronic component mounting substrate comprising an insulating layer positioned between adjacent electrode pads, wherein the insulating layer and the substrate are made of the same material. The electronic component mounting substrate according to claim 1, wherein the insulating layer and the substrate are made of an aluminum oxide sintered body. The electronic component mounting board according to claim 1, wherein the insulating layer has a thickness larger than that of the electrode pad. The electronic component mounting substrate according to claim 1, wherein the insulating layer extends over the entire longitudinal direction between the adjacent electrode pads. 5. The electronic component mounting substrate according to claim 1, an electronic component having a plurality of electrodes and mounted on the mounting portion, the electrode pad of the electronic component mounting substrate, and the electronic component An electronic device comprising: a brazing material that is at least partially interposed between the electrode and the electrode pad and electrically connects the electrode pad. The electronic device according to claim 5, wherein the insulating layer is in contact with a portion located between adjacent electrodes on a surface where each electrode is formed in the electronic component.

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