JP2006032511A - Substrate and mounting substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that, since the adhesive force of electronic parts is insufficient in the conventional mounting method for the electronic parts, a mounting area tends to be made larger and the electronic part is apt to displace in the mounting phase, and it is difficult to make a substrate thin. <P>SOLUTION: The substrate is provided with a conductive electrode for connecting electronic parts and it is used for mounting the electronic parts. In this case, the shape of at least one conductive electrode is nearly the same shape as one section of the electronic parts to be mounted inside. The electronic part is connected to the substrate by using a conductive adhesive agent. Furthermore, the electronic part is placed inside the conductive electrode, and the electronic part and the conductive electrode are arranged side by side on the substrate. In addition, the conductive adhesive agent is applied to the inside of the conductive electrode, and the electronic part is mounted thereon. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a substrate on which an electronic component is mounted and a mounting substrate on which the electronic component is mounted.

  As the demand for downsizing of electronic device products has been increasing recently, electronic components and substrates for mounting the electronic parts have also been downsized. Along with the miniaturization, the conductive electrode for connecting the electronic component on the substrate also needs to be reduced in size and densified, resulting in insufficient adhesion between the electronic component and the substrate. It was happening.

FIG. 5 is a plan view showing a conventional mounting method.
In FIG. 5A, 50 is an electronic component to be mounted, 52 is a substrate on which the electronic component 50 is mounted, and conductive electrodes 54 and 56 for electrically and mechanically connecting the electronic components are provided on the substrate 52. It has been. Here, the electronic component 50 is taken as an example of a two-terminal component provided with electrodes not shown on the left and right.
In FIG. 5B, conductive members 58 and 60 are applied on the conductive electrodes 54 and 56, respectively.
In FIG.5 (c), the electronic component 50 is mounted by the mounter etc. on the conductive electrodes 54 and 56 with which the electroconductive members 58 and 60 were apply | coated, respectively.
In FIG. 5D, the substrate 52 on which the electronic component 50 is placed is passed through a reflow furnace or the like, and heat is applied, so that the conductive electrodes 54 on the substrate are melted and the conductive adhesive is solidified. 56 and the electronic component 50 are electrically and mechanically connected.
In the following drawings, the same members are denoted by the same numbers.

The trend toward downsizing of the electronic component 50 with the recent downsizing wave is remarkable. For this reason, the area where the electronic component 50 and the conductive electrodes 54 and 56 overlap with each other is reduced, and the inadequate adhesive force is remarkable.
In addition, in order to prevent the warpage of the substrate due to the difference in thermal expansion coefficient between the resin constituting the substrate 52 and the copper constituting the electronic component 50 or the conductive electrode, the connection is made by a conductive adhesive that requires a low applied temperature instead of solder. Many methods are also adopted.
However, in order to prevent conduction failure due to oxidation of the surfaces of the conductive electrodes 54 and 56 mainly composed of copper, it is necessary to apply thin gold plating, and there is a problem that the adhesion between the gold and the conductive adhesive is weak. .

FIG. 6 is a diagram showing a conventional measure for improving the adhesive force.
In order to compensate for the insufficient adhesive force, the conductive electrodes 62 and 64 on the substrate 52 are made larger than the conductive electrodes 54 and 56 shown in FIG. A method has been adopted in which the area of the contact portions 66 and 68 with the conductive electrodes 62 and 64 is increased. However, there is a problem that the densification of the substrate 52 is hindered by increasing the conductive electrodes 62 and 64.

  Further, with the downsizing of electronic components, positional displacement of electronic components during mounting has become a problem. This is a phenomenon where the position of the component shifts or the component rises due to the surface tension when the solder or conductive adhesive used for mounting melts or softens. The downsizing of electronic parts has become a big problem.

  FIG. 5D is a diagram illustrating a state in which the electronic component 50 is displaced during the thermal process. Such positional deviation becomes more prominent as the electronic component 50 is reduced in size and mass.

  In order to prevent such misalignment, there is a method in which the electronic component is fixed in advance with an adhesive and then passed through a thermal process, but problems such as increased cost for attaching the electronic component, difficulty in repair, etc. Many.

As a technique for preventing such positional deviation of the electronic component, there is a proposal to make the shape of the conductive electrode substantially the same as the electrode shape of the component to be mounted (see, for example, Patent Document 1).
According to this technology, the positional deviation due to the surface tension of the solder is expected to be reduced, but it is difficult to form a fillet due to solder wetting, and the effect is insufficient when using a conductive adhesive. Many problems remain, such as having no effect on the mounting thickness.

  In addition, the trend toward thinning with the miniaturization of electronic equipment is intensifying, and the mounting substrate is also required to be thinned on the order of microns.

FIG. 7 is a cross-sectional view taken along the line AA ′ of FIG.
In FIG. 7, conductive electrodes 54 and 56 are provided on a substrate 52, and the conductive electrodes 54 and 56 and the electronic component 50 are electrically and mechanically connected by solder or conductive adhesives 58 and 60. . When a conductive adhesive is used, the fillet as shown is not formed because there is no wetting.

As shown in FIG. 7, according to the conventional method, the thickness on the substrate 52 is equal to the thickness of the electronic component 50, and the thickness d1 of the conductive electrodes 54 and 56 and the solder or conductive adhesives 58 and 60 The thickness D was obtained by adding the amount d2 to be lifted.
The copper foil thickness of the conductive electrodes 54 and 56 on the substrate 52 is generally about 35 μm, and this copper foil thickness is a value that cannot be ignored from the recent demand for thinning.

  When the chip component is pressure-bonded to the substrate using an anisotropic conductive film, a land slightly larger than the chip component is provided, and the adhesive protruding from the bottom of the chip component by the pressure applied to the chip component is added to the chip component. A technique has been proposed in which damming is performed by a land and an adhesive is turned around the side wall of the chip (see, for example, Patent Document 2).

Japanese Utility Model Application No. 5-33571 JP 10-313161 A

  The problem to be solved is that the conventional electronic component mounting method has insufficient adhesive strength of the electronic component, and in order to improve it, the mounting area becomes large. It is a point that misalignment occurs, and thinning is difficult.

  The substrate of the present invention has a conductive electrode for connecting an electronic component on which an electronic component is mounted, and the shape of at least one of the conductive electrodes is substantially the same as a portion of the electronic component to be mounted on the inside. And

  The substrate of the present invention is characterized in that the shape is a U-shape.

  The mounting board of the present invention has a shape in which at least one of the conductive electrodes of a board having a conductive electrode for connecting an electronic component on which the electronic component is mounted has a size approximately equal to a portion of the electronic component to be mounted on the inside. And the electronic component is connected to the substrate by a conductive member.

  The mounting substrate of the present invention is a substrate having an electronic component connecting conductive electrode for mounting an electronic component, and the shape of at least one of the conductive electrodes is substantially the same as a fraction of the electronic component to be mounted inside, The electronic component is placed inside the conductive electrode, and the electronic component and the conductive electrode are arranged side by side on the substrate.

  The mounting board of the present invention is characterized in that the shape is a U-shape.

  In the preceding item, the electronic component is connected to the substrate by a conductive member.

  Furthermore, in the preceding paragraph, the conductive member is applied at least inside the conductive electrode, and the electronic component is mounted thereon.

  In the mounting board of the present invention, the conductive member is a conductive adhesive such as solder or silver paste.

  Furthermore, the mounting board of the present invention is characterized in that the electronic component is a surface mount type component such as a chip resistor, a chip capacitor, a chip LED, a chip transistor, or a melf resistor.

  According to the present invention, the adhesive strength between the electronic component and the substrate is improved, the electronic component is less likely to be misaligned, and the mounting substrate can be made thinner.

  In the substrate having the electronic component connecting conductive electrode on which the electronic component is mounted, the shape of at least one of the conductive electrodes is set to a shape approximately equal to the size of the electronic component to be mounted on the inside. The electronic component was connected to the substrate with a conductive member. Furthermore, the electronic component was placed inside the conductive electrode, and the electronic component and the conductive electrode were placed side by side on the substrate. Furthermore, the conductive member is applied at least inside the conductive electrode, and the electronic component is mounted thereon. As the conductive member, a conductive adhesive such as solder or silver paste was used.

FIG. 1 is a plan view showing a first embodiment of a board and a mounting board according to the present invention, and shows a procedure for mounting a surface-mount type electronic component 50 on a board 52.
In FIG. 1A, reference numeral 50 denotes an electronic component whose electrode part has a square shape, 52 is a substrate according to the present invention, and the substrate 52 has a U-shaped electron whose inner shape matches the electrode shape of the electronic component 50. The component connecting conductive electrodes 10 and 12 are provided, and the base material is made of resin. The insides of the U-shaped conductive electrodes 10 and 12 have a size substantially equal to one stroke of the electronic component 50, as is apparent from the drawing. Here, the electronic component 50 is an example of a two-terminal component provided with electrodes not shown on the left and right sides, and the inside of the U-shape is substantially the same as the shape of the left and right electrode portions and slightly larger. It has become.
In FIG. 1B, conductive members 13 and 16 are respectively applied on the inside of the U-shape of the conductive electrodes 10 and 12, or the inside of the U-shape and the conductive electrodes. Reference numeral 13 denotes a conductive member applied to the inside of the U-shape, and 16 denotes a conductive member applied to the inside of the U-shape and on the conductive electrode.
Here, cream solder or a conductive adhesive can be used as the conductive member.
Whether the conductive member is applied in the shape indicated by 13 or 16 may be determined by production technical factors such as the amount of the conductive member and the pressure applied when the electronic component 50 is mounted. However, in any case, the conductive member is applied at least inside the U-shape.
Such a method of coating the inside of the U-shape is particularly effective when an electronic component is bonded with a conductive adhesive.

In FIG.1 (c), the electronic component 50 is mounted by the mounter etc. inside the U-shape of the conductive electrodes 10 and 12 with which the electroconductive members 14 and 16 were apply | coated, respectively. Here, the conductive members 14 and 16 are plotted on the assumption that they are applied in the shape indicated by 16 in FIG.
What is characteristic here is that the electronic component 50 is placed on the U-shaped portion of the conductive electrodes 10 and 12 and there is no overlapping portion of the electronic component 50 and the conductive electrodes 10 and 12. Therefore, the electronic component 50 and the conductive electrodes 10 and 12 are juxtaposed on the substrate 52.
Pressure is applied when placing the electronic component 50. Due to this pressure, the conductive member applied to the U-shaped portion protrudes onto the conductive electrodes 10 and 12. As described in Patent Document 2, the conductive electrodes 10 and 12 function as lands that dam the conductive member, and function to turn the conductive member around the side wall portion of the electronic component 50.

In FIG. 1D, a substrate 52 on which an electronic component 50 is placed is passed through a reflow furnace or the like and heat is applied, and the conductive electrodes 10 and 10 on the substrate are melted by solder, solidified by a conductive adhesive, and the like. 12 and the electronic component 50 are electrically and mechanically connected. At this time, since the electronic component 50 is placed on the U-shaped portions of the conductive electrodes 10 and 12, the conductive electrodes 10 and 12 function as positioning guides and do not cause misalignment.
Such a mounting method is particularly effective when a conductive adhesive is used. Copper is generally used for the conductive electrode, and its surface is gold-plated to prevent oxidation, but the resin of the conductive adhesive does not have sufficient adhesion to gold. However, in the mounting substrate of the present invention, since the conductive adhesive bonds the electronic component 50 and the substrate 52 at the resin portion without gold inside the U-shaped electrode, a strong adhesive strength between the resin and the resin can be obtained. Further, since the conductive adhesive wraps around the side surfaces of the conductive electrodes 10 and 12, the anchor effect is increased and the adhesive strength is further improved. On the other hand, since both the conductive adhesive and the conductive electrode have a sufficiently small specific resistance, a wide bonding area is not required for electrical connection.

FIG. 8 is a diagram showing various shapes of the electrodes of the electronic component and the shapes of the corresponding conductive electrodes.
8A, the electrode part 72 of the electronic component 74 has a square shape as in FIG. 1, and the inner shape of the conductive electrode 70 has a quadrangular shape corresponding to the shape. As a result, the entire conductive electrode 70 has a U shape. The inner shape of the U-shape is substantially equal to the shape of the electrode portion 72 of the electronic component 74 and slightly larger.
In FIG. 8B, the electrode part 78 of the electronic component 80 has a semi-elliptical shape, and the entire shape of the conductive electrode 76 is a shape obtained by hollowing out a semi-elliptical shape from a square according to the shape. The inner shape of the conductive electrode 76 is substantially the same as the shape of the electrode part 78 of the electronic component 80 and is slightly larger.
In FIG. 8C, the electrode part 84 of the electronic component 86 has a convex shape, and the entire shape of the conductive electrode 82 is a shape obtained by hollowing out the convex shape from a square according to the shape. The inner shape of the conductive electrode 82 is substantially the same as the shape of the electrode portion 84 of the electronic component 86 and is slightly larger.
In FIG. 8D, the square electrode portion of the electronic component 96 is separated into two electrode portions 92 and 94, and the conductive electrodes are separated into 88 and 90 according to the shape. The overall inner shape of the conductive electrodes 88 and 90 together is a quadrangle, and as a result, the conductive electrodes 88 and 90 as a whole are U-shaped and separated at the center. The inner shape of the U-shape is substantially equal to the shape of the side where the electrode portions 92 and 94 of the electronic component 96 are provided, and is slightly larger.
In this way, the portion where the electrode of the electronic component is provided may have various shapes, but the present invention is substantially the same shape as the portion of the electronic component on which the shape of the conductive electrode connecting the electronic component is mounted. It is said.

FIG. 2 is a sectional view taken along the line BB ′ of FIG.
In FIG. 2, conductive electrodes 10 and 12 are provided on a substrate 52. The conductive electrodes 10 and 12 and the electronic component 50 are electrically and mechanically connected by conductive members 14 and 16 made of solder or a conductive adhesive. It is connected to the. Since FIG. 2 shows a case where a conductive adhesive is used, no fillet is formed.

  As shown in FIG. 2, the mounting board of the present invention has a relationship in which the electronic component 50 and the conductive electrodes 10 and 12 do not overlap each other on the board, and the thickness on the board 52 is The thickness D is obtained by adding the thickness of the electronic component 50 to which the solder or the conductive adhesives 10 and 16 lift the electronic component 50. In other words, the conductive electrodes 10 and 12 are made thinner by about 35 μm than the prior art FIG.

FIG. 3 is a plan view showing a second embodiment of the substrate and the mounting substrate according to the present invention, and shows a procedure for mounting the surface-mounted transistor 20 having three terminals 22, 24, and 26 on the substrate 52.
3A is a diagram showing a transistor 20 having three terminals, and FIG. 3B is a diagram showing a substrate 52 according to the present invention. The substrate 52 has a U-shaped conductive electrode 28 for connecting an electronic component, 30 and 32 are provided, and the base material is made of resin. The insides of the U-shaped conductive electrodes 28, 30, 32 are substantially equal to and slightly larger than the terminals 22, 24, 26 of the three-terminal transistor 20, as is apparent from the drawing.
In FIG.3 (c), the electroconductive members 34, 36, and 38 are apply | coated to the inside of the U-shape of the electroconductive electrodes 28, 30, and 32, and the electroconductive electrode, respectively.
Here, as in the first embodiment, cream solder or conductive adhesive can be used as the conductive member.

In FIG. 3D, the three-terminal transistor 20 is mounted by a mounter or the like inside the U-shapes of the conductive electrodes 28, 30, and 32 to which the conductive members 34, 36, and 38 are applied, respectively.
Hereinafter, the effect when the three-terminal transistor 20 is connected to the substrate 52 by reflow or the like is the same as that of the first embodiment.
As described above, the substrate and the mounting substrate according to the present invention are not limited to two-terminal electronic components, but are also effective for three-terminal, more multi-terminal electronic components, and odd-shaped electronic components.

FIG. 4 is a plan view showing a third embodiment of a substrate and a mounting substrate according to the present invention, and shows a procedure for mounting a so-called Melf-type surface-mounted cylindrical electronic component on the substrate 52.
FIG. 4A is a diagram showing a Melf type electronic component 40, and electrodes 42 and 44 are provided at both ends of a cylindrical component.
FIG. 4B is a view showing a substrate 52 according to the present invention. The substrate 52 is provided with U-shaped conductive electrodes for connecting electronic parts 46 and 48, and the base material is made of resin. Unlike the first and second embodiments, the dimension d inside the U-shaped conductive electrodes 46 and 48 is set smaller than the diameter of the cylindrical electronic component 40.
In FIG.4 (c), the electroconductive members 47 and 49 are apply | coated on the inside of the U-shape of the electroconductive electrodes 46 and 48, and the electroconductive electrode, respectively.
Here, as in the case of the first and second embodiments, cream solder or conductive adhesive can be used as the conductive member.

In FIG. 4D, the melf type electronic component 40 is mounted by a mounter or the like inside the U-shape of the conductive electrodes 46 and 48 to which the conductive members 47 and 49 are applied, respectively.
FIG. 4E is a diagram showing a cross section taken along the line CC ′ of FIG. 4D. In FIG. 4E, a conductive electrode 46 is provided on the substrate 52. The component 40 is electrically and mechanically connected by a conductive member 47 which is solder or a conductive adhesive.

As shown in FIG. 4E, in the mounting substrate of the present invention, the diameter Φ of the Melf type electronic component 40 is larger than the dimension d inside the U-shaped conductive electrode 46, but in the vicinity of the U-shaped conductive electrode 46. The dimension d is set so that the Melf type electronic component 40 and the conductive electrode 46 do not overlap. Therefore, since the melf type electronic component 40 and the conductive electrode 46 are arranged side by side, the thickness on the substrate 52 is equal to the thickness of the melf type electronic component 40 and the conductive member 47 lifts the melf type electronic component 40. The thickness D is obtained by adding the thicknesses of. That is, it is possible to reduce the thickness of the conductive electrode 146 by the thickness of the copper foil as compared with the prior art.
Further, in the case of the Melf type electronic component, when it is placed on the substrate as shown in FIG. 4 (d), the positional deviation due to rolling is a big problem, but in this embodiment, the conductive electrode 46 is misaligned. There is also an effect that the parts can be arranged accurately because it functions as a guide plate for prevention.
Furthermore, there is an effect of preventing misalignment when the melf type electronic component 40 is connected to the substrate 52 by reflow or the like, and the adhesive strength between the substrate 52 and the melf type electronic component 40 when a conductive adhesive is used as the conductive member. The effect that can be increased is the same as that of the first embodiment.
As described above, the substrate and the mounting substrate according to the present invention are also effective for odd-shaped parts such as Melf type.

  As described above, when the substrate and the mounting substrate according to the present invention are used, the adhesive strength of the components is improved, the positional deviation at the time of mounting is eliminated, the thickness can be reduced, and the effect is great.

It is the top view which showed the 1st Example of the board | substrate and mounting board | substrate by this invention. It is B-B 'sectional drawing of FIG.1 (d). It is the top view which showed the 2nd Example of the board | substrate and mounting board | substrate by this invention. It is the figure which showed the 3rd Example of the board | substrate and mounting board | substrate by this invention. It is the top view which showed the conventional mounting method. It is the figure which showed the conventional policy for improving adhesive force. It is A-A 'sectional drawing of FIG.5 (d). It is the figure which showed the various shapes of the electrode of an electronic component, and the shape of the electroconductive electrode corresponding to it.

Explanation of symbols

20, 40, 50, 74, 80, 86, 96 Electronic components 10, 12, 28, 30, 32, 46, 48, 70, 76, 82, 88, 90 Conductive electrode 52 Substrate 14, 16, 34, 36, 38, 47, 49 Conductive member

Claims (9)

In a substrate having an electronic component connecting conductive electrode for mounting an electronic component,
A substrate characterized in that the shape of at least one of the conductive electrodes is substantially the same as a stroke of an electronic component to be mounted inside.   The substrate according to claim 1, wherein the shape is a U-shape. Of a substrate having a conductive electrode for connecting an electronic component for mounting the electronic component,
The shape of at least one of the conductive electrodes is substantially the same as a stroke of the electronic component mounted on the inside;
A mounting board, wherein the electronic component is connected to the board by a conductive member. Of a substrate having a conductive electrode for connecting an electronic component for mounting the electronic component,
The shape of at least one of the conductive electrodes is substantially the same as a stroke of the electronic component mounted on the inside;
The electronic component is mounted on the inside of the conductive electrode, and the electronic component and the conductive electrode are placed side by side on the substrate.   5. The mounting board according to claim 3, wherein the shape is a U-shape.   6. The mounting board according to claim 4, wherein the electronic component is connected to the board by a conductive member.   7. The mounting board according to claim 3, wherein the conductive member is applied at least inside the conductive electrode, and the electronic component is mounted thereon.   The mounting substrate according to claim 3, 5, 6, or 7, wherein the conductive member is a conductive adhesive such as solder or silver paste. 9. The mounting substrate according to claim 3, wherein the electronic component is a surface-mounted component such as a chip resistor, a chip capacitor, a chip LED, a chip transistor, or a Melf resistor.

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