JP2005159185A - Electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable electronic device by decreasing exfoliation between a circuit board and a resin material, and occurrence of chipping of the circuit board. <P>SOLUTION: The electronic device 10 comprises an electronic component element 2 mounted on an upper surface of a rectangular circuit board 1, and a resin material 3 covering the device. A notch 1a with its lower end disengaged from the lower surface of the board 1 and with its upper end opened to the upper surface of the board 1 is formed at four corners of the board 1. A part of the resin material 3 is filled in a region in which the notch 1a is formed, and the filled resin material 3 is adhered to the side of the board 1 which faces to the notch 1a. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electronic device such as a composite electronic component used in various devices.

  Conventionally, electronic devices have been widely used as composite electronic components used in various devices. Such electronic devices have electronic component elements mounted on the upper surface of a rectangular circuit board and covered with a resin material. The thing of the structure which was made is known (for example, refer patent document 1).

  Such an electronic device can be obtained by dividing a plurality of mother substrates. Specifically, for example, an electronic component element is mounted on each substrate region of a plurality of mother boards to be divided into a substrate region and a disposal margin region, and a liquid resin is applied to all substrate regions of the plurality of mother substrates. After coating, the electronic component element is covered with a sealing resin that is heated and polymerized, and finally, a plurality of mother substrates are cut along the outer periphery of the substrate region together with the sealing resin, thereby providing an electronic The device is manufactured.

In the above-described multiple-taken mother board, a plurality of rectangular substrate regions are arranged in a matrix, and a frame-shaped discard margin region is arranged so as to surround these substrate regions. It has a configuration.
JP 2000-252308 A

  However, when an external impact is applied to the conventional electronic device, peeling between the circuit board and the resin material may occur particularly starting from the four corners. Water or the like easily penetrates into the interface, and when water or the like penetrates into the interface, the characteristics of the electronic component element mounted on the upper surface of the circuit board fluctuate, and the reliability of the electronic device deteriorates.

  In addition, the four corners of the rectangular circuit board are formed during transport in a process such as a characteristic inspection performed after cutting a plurality of mother boards to be cut into a plurality of rectangular substrate areas or a process of mounting an electronic device on a mother board or the like. However, chipping may occur due to collision with the transport jig, and even when a part of the circuit board is chipped in this way, the reliability of the electronic device is deteriorated.

  The present invention has been devised in view of the above-described problems, and an object of the present invention is to reduce the occurrence of peeling between the circuit board and the resin material and chipping of the circuit board, thereby providing a highly reliable electronic device. It is to provide.

  The electronic device of the present invention is an electronic device in which an electronic component element is mounted on an upper surface of a rectangular circuit board, and this is covered with a resin material, and the lower ends are formed at the four corners of the circuit board from the lower surface of the circuit board. A circuit that forms a notch that is spaced apart and has an upper end opened in the upper surface of the circuit board, and that fills a portion of the resin material in the notch formation region, and that faces the notched resin material It is characterized by being attached to the side surface of the substrate.

  The electronic device according to the present invention is characterized in that the surface of the resin material filled in the notch formation region is matched with the contour of the bottom corner of the circuit board.

  Furthermore, in the electronic device according to the present invention, the circuit board is formed by laminating a plurality of insulating layers, and the side surface of the circuit board facing the notch is shifted for each insulating layer to be uneven. It is characterized by this.

  Furthermore, in the electronic device of the present invention, the amount of displacement of the insulating layer is 10% to 100% with respect to the distance from the corner of the circuit board on the bottom surface of the notch to the side surface of the circuit board facing the notch. It is characterized by being set.

  Furthermore, the electronic device according to the present invention is characterized in that a side surface of the circuit board facing the notch has a zigzag shape.

  According to the electronic device of the present invention, at the four corners of the circuit board, a notch whose upper end is opened on the upper surface of the circuit board is formed, and a part of the resin material is filled in a formation region of the notch, By adhering the filled resin material to the side surface of the circuit board facing the notch, the circuit board and the resin material at the four corners of the circuit board are joined to the wall surface of the circuit board looking into the notch. Since the adhesion between the circuit board and the resin material is less likely to occur, water or the like permeates the interface between the circuit board and the resin material and is mounted on the upper surface of the circuit board. It is possible to reduce the deterioration of the reliability of the electronic device by changing the characteristics of the component elements. In addition to this, even when the four corners of the rectangular circuit board collide with the transport jig during transport, chipping is less likely to occur because part of the resin material is placed in the four corners. This also reduces the deterioration of the reliability of the electronic device.

  On the other hand, since the lower end of the notch is separated from the lower surface of the circuit board, a sufficient effective area for forming a conductor pattern is secured on the back surface of the circuit board.

  According to the electronic device of the present invention, the surface of the resin material filled in the notch formation region is matched with the contour of the lower surface corner of the circuit board. Since the resin material does not protrude from each side, it is difficult for the electronic device to be caught by the transport jig during transport.

  Further, according to the electronic device of the present invention, the circuit board is formed by laminating a plurality of insulating layers, and the side surface of the circuit board facing the notch is shifted unevenly for each insulating layer. As a result, the bonding force between the wall surface of the circuit board and the resin material that is notched in the notch is further strengthened, and the occurrence of peeling between the circuit board and the resin material is further reduced.

  Furthermore, according to the electronic device of the present invention, the amount of displacement of the insulating layer is 10% to 100% with respect to the distance from the corner of the circuit board on the bottom surface of the notch to the side surface of the circuit board facing the notch. By setting the%, the bonding force between the wall surface of the circuit board and the resin material looking into the notch is further strengthened, and the occurrence of peeling between the circuit board and the resin material is further reduced. Become.

  Furthermore, according to the electronic device of the present invention, since the side surface of the circuit board facing the notch is formed in a zigzag shape, the bonding force between the wall surface of the circuit board looking into the notch and the resin material is further increased. As a result, the occurrence of peeling between the circuit board and the resin material is further reduced.

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

  1 is an external perspective view of an electronic device according to an embodiment of the present invention, FIG. 2 is a sectional view thereof, and FIG. 3 is an external perspective view of a circuit board used in the electronic device according to an embodiment of the present invention. An electronic device 10 shown in FIG. 1 has a structure in which an electronic component element 2 is mounted on a top surface of a rectangular circuit board 1 and is covered with a resin material 3.

  The circuit board 1 has a configuration in which a plurality of insulating layers 1h to 1k are stacked, and the thickness of the insulating layer is set to 20 μm to 300 μm, for example, and the material thereof is relatively, for example, 800 ° C. to 1200 ° C. A glass-ceramic material that can be fired at a low temperature is preferably used.

Specific examples of the ceramic material constituting the glass-ceramic material include cristobalite, quartz, corundum (α-alumina), mullite, cordierite, and other insulating ceramic materials, BaTiO ₃ , Pb ₄ Fe ₂ Nb ₂ O ₁₂ , TiO ₂ or the like, or a magnetic ceramic material such as Ni-Zn ferrite or Mn-Zn ferrite (referred to as ceramic in a broad sense) is used. In addition, the average particle diameter of 1.0 to 6.0 μm, preferably 1.5 to 4.0 μm is used. Further, two or more ceramic materials may be mixed and used. In particular, use of corundum is advantageous in terms of cost.

In addition, as a material of the glass material, crystals of cordierite, mullite, anorthite, serzian, spinel, garnite, willemite, dolomite, petalite, substituted derivatives thereof, and crystal phases of spinel structure are precipitated by firing. For example, B ₂ O ₃ , SiO ₂ , Al ₂ O ₃ , ZnO, glass frit containing an alkaline earth oxide, or the like is preferably used. Such a glass frit has a wide vitrification range and a yield point in the vicinity of 600 to 800 ° C.

  Although not shown in the figure, the circuit board 1 has a conductor pattern serving as a circuit pattern and a component mounting pad inside and on the main surface. The conductive pattern is selected in consideration of the compatibility with the dielectric material forming the insulating layers 1h to 1k, and the conductive pattern is, for example, a conductive material mainly composed of an Ag alloy such as Ag, Ag-Pd, or Ag-Pt. It is formed of a material, a Cu-based material, a W-based material, a Mo-based material, a Pd-based conductive material, or the like, and the thickness thereof is set to, for example, 5 to 25 μm.

  The electronic component element 2 mounted on the upper surface of the circuit board 1 is an active element such as a passive component element such as an inductance, a capacitor, or a resistor, a crystal resonator, a thermistor, a transistor, a varicap diode, or an IC chip. An electric circuit is configured together with the circuit pattern.

  The resin material 3 that covers the electronic component element 2 is made of an organic material such as epoxy or phenol, and has a role of preventing the electronic component element 2 from being directly impacted from the outside or from adhering foreign substances.

  The electronic device 10 having the above-described configuration is produced by the following manufacturing method.

First, a powder obtained by mixing 60 wt% of CaO—Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ glass powder and 40 wt% of alumina powder, a plasticizer such as DOP, and an acrylic resin or a butyral resin, for example. And a solvent such as toluene, xylene, and alcohol are added and kneaded sufficiently to prepare a slurry having a viscosity of 2000 to 40000 cps, and a plurality of ceramic green sheets for low-temperature firing are formed by a doctor blade method. .

  The ceramic green sheet used in the present embodiment is partitioned into a plurality of substrate regions arranged in a matrix and a frame-shaped discarding region surrounding these substrate regions.

  Next, using a punching die, punching machine, etc., for each ceramic green sheet other than the ceramic green sheet that is the lowest layer, penetrate through the ceramic green sheet in the thickness direction so that the four corners of each substrate area are notched Holes are punched and formed. Moreover, such a through hole is set so that the hole diameter becomes 0.2 mmφ after firing, for example. Although not shown in the drawing, another through-hole serving as a via hole can be simultaneously formed at a predetermined position of each substrate region, and a conductor paste such as Ag, Ag-Pd, Au, Cu or the like can be formed in each via hole. By filling, a via hole conductor is formed. Moreover, a conductor pattern for wiring is screen-printed on each ceramic green sheet as necessary.

  Next, a laminated green sheet is obtained by laminating a plurality of such ceramic green sheets.

  In this embodiment, the laminated green sheet is a ceramic in which through holes are formed at the four corners of each substrate region on the lowermost ceramic green sheet where the through holes are not formed at the four corners of each substrate region. The green sheets are stacked.

  Next, the above-mentioned laminated green sheet is pressurized in the lamination direction under conditions of, for example, 80 to 150 ° C. and 5 to 25 MPa, and air remaining between the ceramic green sheets is released to the outside through the through holes. Then, the ceramic green sheets constituting the laminated green sheet are pressure-bonded to each other to form a laminated body.

  Thus, in the laminate of this embodiment, when the laminated green sheet is pressed in the laminating direction, air remaining between adjacent ceramic green sheets is released to the outside through the through holes. It is difficult for a gap to be formed between the insulating layers 1h to 1k.

  Next, the obtained laminated body is fired in air at 900 ° C. for 20 minutes using a firing furnace, so that a plurality of mother substrates 41 as shown in FIG. 4 are manufactured. . When the conductive paste is Ni or Cu, it is fired in a reducing or neutral atmosphere.

  In addition, the plurality of mother substrates 41 thus obtained have a structure in which concave portions 41a that open to the upper surface are formed at the four corners of the substrate region.

  Next, the electronic component element 2 is mounted on the component mounting pad on the upper surface of the substrate area to which solder cream has been applied in advance by screen printing or the like, and then the plurality of mother substrates 41 are passed through a reflow furnace or the like. By heating and heating, a plurality of mother boards 41 for taking a plurality of electronic component elements 2 mounted on each substrate region as shown in FIG. 5 is obtained.

  Then, by applying a liquid resin over the entire substrate area of the upper surface of the multiple substrate 41 on which the electronic component element 2 is mounted, filling a part of the liquid resin into the recess 41a, and heating and polymerizing the liquid resin, A resin material 3 covering the electronic component element 2 is formed.

  Then, using a dicing blade or the like, the plurality of mother substrates 41 are cut along with the resin material 3 along the outer periphery of the substrate region so as to pass through the central region of the recess 41a. In this way, a circuit board 1 having a rectangular shape corresponding to the board area of the plurality of mother boards 41 is obtained, and the electronic component element 2 is mounted on the upper surface of the circuit board 1. A plurality of electronic devices 10 covered with the resin material 3 are manufactured.

  In the case of such an electronic device 10, in the above-described process for manufacturing the multiple-taken mother board 41, through-holes are not formed in the four corners of each substrate region in the lowermost ceramic green sheet. Thus, the through-hole formed in the ceramic green sheet does not penetrate both main surfaces of the laminated green sheet, and the applied liquid resin does not enter the other main surface, so that the electrode connected to the outside formed on the lower surface of the circuit board 1 A portion of the resin material 3 that has wrapped around is no longer covered with the resin material 3. Therefore, poor electrical connection when the electronic device 10 of the present embodiment is mounted on a motherboard or the like is reduced.

  In addition, since the recess 41a is formed in the portion where the four substrate regions are in contact with each other in the mother board 41 for taking a plurality of pieces, the recess 41a forms notches 1a formed at the four corners of the circuit board 1 after cutting. Become.

  In the electronic device 10 of the present embodiment, notches 1a whose upper ends are opened on the upper surface of the circuit board 1 are formed at the four corners of the circuit board 1, and a part 3a of the resin material 3 is formed in the formation region of the notch 1a. And the filled resin material 3 is attached to the side surface of the circuit board facing the notch 1a. With such a structure, the connection between the wall surface of the circuit board and the resin material 3 seen in the notch 1a reinforces the bonding force between the circuit board and the resin material at the four corners of the circuit board 1. As a result, water or the like permeates into the interface between the circuit board and the resin material, and the characteristics of the electronic component elements mounted on the upper surface of the circuit board are changed to deteriorate the reliability of the electronic device. Is reduced.

  In addition to this, even when it collides with the conveyance jig during conveyance, the four corners of the rectangular circuit board 1 are less likely to be chipped because part of the resin material is arranged at the four corners. This also reduces the deterioration of the reliability of the electronic device 10.

  On the other hand, since the lower end of the notch 1a is separated from the lower surface of the circuit board 1 by the lowermost insulating layer 1k, a sufficient effective area for forming a conductor pattern is ensured on the back surface of the circuit board 1. It becomes.

  In addition, the electronic device 10 according to the present embodiment has a structure in which the surface of the resin material 3 filled in the notch 1 a formation region is matched with the contour of the lower surface corner of the circuit board 1. By adopting such a structure, the resin material 3 does not protrude from each side of the rectangular circuit board 1, so that the problem that the electronic device 10 is caught by the conveyance jig during conveyance is less likely to occur. ing.

  Furthermore, in the present embodiment, the side surface of the notch 1a of the circuit board 1 is zigzag due to the deviation generated when the ceramic green sheets are laminated, and the amount of deviation is the circuit on the bottom surface of the notch 1a. It is set to 10% to 75% with respect to the average distance from the corner of the substrate 1 to the side surface of the circuit board 1 facing the notch 1a.

  As described above, the circuit board 1 is formed by laminating the plurality of insulating layers 1h to 1k, and the side surface of the circuit board 1 facing the notch is shifted for each insulating layer to be uneven. As a result, the bonding force between the wall surface of the circuit board 1 and the resin material 3 seen in the notch 1a is further strengthened, and the occurrence of peeling between the circuit board 1 and the resin material 3 is further reduced.

  Further, the shift amount of the insulating layers 1h to 1k is set to 10% to 100% with respect to the average distance from the corner of the circuit board 1 to the side surface of the circuit board 1 facing the notch 1a at the bottom surface of the notch 1a. Even if this is done, the bonding force between the wall surface of the circuit board and the resin material that is notched in the notch 1a is further strengthened, and the occurrence of peeling between the circuit board and the resin material is further reduced.

  Particularly in the structure described above, the side surface of the circuit board 1 facing the notch 1a is formed in a zigzag shape, so that the bonding force between the wall surface of the circuit board 1 looking into the notch 1a and the resin material 3 is further strengthened. As a result, the occurrence of peeling between the circuit board 1 and the resin material 3 is further reduced.

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

  For example, in the embodiment described above, the step of mutually pressing the ceramic green sheets constituting the laminated green sheet is performed after laminating a plurality of ceramic green sheets. By doing so, a laminated green sheet may be formed. Also by this method, the air remaining between the ceramic green sheets is discharged to the outside through the through holes, and the same effect as in this embodiment can be obtained. .

  In the embodiment described above, a dicing blade is used as a means for cutting the laminate 3 into the respective substrate regions 4. However, a dividing groove is formed in advance on the surface of the laminate 3, and the dividing groove is used as a fulcrum. A plurality of multilayer ceramic parts may be obtained by performing a break treatment.

  Note that, in the process of manufacturing the mother substrate 41 for taking multiple pieces, only the lowermost ceramic green sheet has a structure in which through holes are not formed in the four corners of each substrate region. It is to eliminate the existence of holes penetrating both main surfaces as a laminate, and if this is achieved, through holes are formed at the four corners of each substrate region for the lowermost layer and a plurality of adjacent layers. It does not matter even if it is not configured.

1 is an external perspective view of an electronic device according to an embodiment of the present invention. It is sectional drawing of the electronic device which concerns on one Embodiment of this invention. It is an external appearance perspective view of the circuit board used for the electronic device which concerns on one Embodiment of this invention. 1 is an external perspective view of a plurality of mother boards for use in manufacturing an electronic device according to an embodiment of the present invention. 1 is an external perspective view in which electronic component elements are mounted on a plurality of mother boards used for manufacturing an electronic device according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Circuit board 1a ... Notch 1h-1k ... Insulating layer 2 ... Electron nest element 3 ... Resin material 10 ... Electronic device 41 ... Mother board for taking multiple pieces 41a ... concave portion

Claims (5)

In an electronic device in which an electronic component element is mounted on the upper surface of a rectangular circuit board and this is covered with a resin material,
A notch is formed at the four corners of the circuit board, the lower end being separated from the lower surface of the circuit board and the upper end being opened on the upper surface of the circuit board, and a part of the resin material is filled in the notch forming region. An electronic apparatus comprising: the resin material filled; and being attached to a side surface of the circuit board facing the notch. 2. The electronic device according to claim 1, wherein a surface of the resin material filled in the notch formation region is matched with a contour of a lower surface corner portion of the circuit board. 2. The circuit board is formed by laminating a plurality of insulating layers, and the side surface of the circuit board facing the notch is shifted in each insulating layer to form an uneven shape. Alternatively, the electronic device according to claim 2. The amount of displacement of the insulating layer is set to 10% to 100% with respect to the average distance from the corner of the circuit board at the bottom surface of the notch to the side surface of the circuit board facing the notch. The electronic device according to claim 3. The electronic device according to claim 1, wherein a side surface of the circuit board facing the notch has a zigzag shape.

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