JP2006310583A - Composite substrate and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite substrate in which insulation performance between adjacent conductors can be enhanced, and in addition, cost reduction can be realized, and to provide a manufacturing method thereof. <P>SOLUTION: A non-conductive resin film 7 deformable by an external force is provided on the surface of a conductive section 4 of a substrate 1, and connection particles 9 made of a conductive material and each having an external diameter wider than the inside diameter of each of openings 8 are arranged so that one part of each of the particles is positioned in the openings 8. Substrates 1 and 2 are pressed in a direction of the substrates coming close to each other to crush the connection particles 9 and push away the non-conductive resin, thereby jointing the conductive portions 4 and 6 through the connection particle 9 and making them conducting. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a composite substrate obtained by bonding a plurality of substrates and a method for manufacturing the same.

Along with the reduction in size and weight of electronic devices, a composite substrate in which a plurality of circuit boards are bonded to each other is used.
As a composite substrate, there is one in which a pair of substrates are joined using an anisotropic conductive film (see, for example, Patent Document 1).
FIG. 12 shows an example of a composite substrate using an anisotropic conductive film. In this composite substrate, the first substrate 1 and the second substrate 2 are bonded via an anisotropic conductive film 31. .
In the first and second substrates 1 and 2, terminals 4 and 6 (conductive portions) are formed on one surface of the base materials 3 and 5, respectively. The anisotropic conductive film 31 is obtained by dispersing conductive particles 32 in a resin material 33.
In this composite substrate, the terminals 4 and 6 are electrically connected by the conductor particles 32 interposed between the terminals 4 and 6.
JP-A-5-191008

The composite substrate has a problem that the cost increases because the expensive anisotropic conductive film 31 is used. Further, since the anisotropic conductive film 31 including the conductive particles 32 is filled between the terminals 4 and 6 and the terminals 4 and 6 adjacent thereto, the insulation between the terminals 4 and 6 is insufficient. It was easy to become.
In the composite substrate, since the electrical continuity of the terminals 4 and 6 depends on the contact between the conductor particles 32 and the terminals 4 and 6, the resistance value between the terminals 4 and 6 is smaller than that of solder bonding. There is a problem of becoming higher.
The present invention has been made in view of the above circumstances, and can improve the insulation between adjacent conductive parts, and can improve the conductivity of the conductive parts to be connected, and can reduce the cost. An object of the present invention is to provide a composite substrate and a manufacturing method thereof.

A method of manufacturing a composite substrate according to claim 1 of the present invention is a method of manufacturing a composite substrate in which a pair of substrates having conductive portions are bonded to each other, and is provided on the surface of at least one conductive portion of the pair of substrates. A film installation step for installing a non-conductive resin film having an opening and deformable by an external force, and a part of connection particles made of a conductive material and having an outer diameter larger than the inner diameter of the opening. The conductive resin film is disposed so as to be positioned in the opening, and the connection particles are crushed by pressing the pair of substrates in a direction approaching each other, and the non-conductive resin is pushed away to pass through the connection particles. And a pressing step for joining the conductive portions so as to be conductive.
A method for manufacturing a composite substrate according to a second aspect of the present invention is characterized in that, in the first aspect, the pushed nonconductive resin forms an insulating portion around the conductive portion.
The method for producing a composite substrate according to claim 3 of the present invention is the method according to claim 1 or 2, wherein the nonconductive resin is a thermosetting resin, and the nonconductive resin that has undergone the pressing step is cured by heating. It is characterized by that.
The method for manufacturing a composite substrate according to a fourth aspect of the present invention uses the pressing plate according to any one of the first to third aspects, using a placement plate having a fitting opening portion into which the connection particles can be fitted. The connecting particles sandwiched between the conductive portions in FIG. 5 are arranged on the surface of the conductive layer in a state of being fitted in the fitting opening portion.
In the manufacturing method of the composite substrate according to claim 5 of the present invention, in any one of claims 1 to 3, a placement plate having a passage opening through which the connection particles can pass is used, and in the pressing step, The connecting particles sandwiched between the conductive portions are disposed on the surface of the conductive layer by dropping from the passage opening portion.

  A composite substrate according to claim 6 of the present invention is a composite substrate in which a pair of substrates having conductive portions are bonded to each other, and the conductive portions are compressed between the pair of substrates and the conductive portions of these substrates. It is characterized by comprising connecting particles that are joined so as to be conductive, and an insulating portion formed around the conductive portion by pressing and deforming a nonconductive resin formed on the surface of the conductive portion.

In the production method of the present invention, a non-conductive resin film having an opening is used, connecting particles having an outer diameter larger than the inner diameter of the opening are arranged in the opening, and the connecting particles are crushed by pressing the substrate. The conductive resin is pushed away, and the conductive portions are joined to each other through the connection particles so as to be conductive.
By using connecting particles whose outer diameter is larger than the inner diameter of the opening, it becomes difficult for the connecting particles to roll in the opening, thereby preventing displacement of the connecting particles and joining the connecting particles to the conductive portion at an accurate position. Can do.
Moreover, since the conductive parts are joined by the crushed connecting particles, the conductivity between them can be increased.
Further, the pushed non-conductive resin can enhance the insulation between the adjacent conductive portions and can increase the bonding strength of the substrates.
Further, the non-conductive resin can be easily and surely disposed between the adjacent conductive portions, the manufacturing process can be simplified, and the manufacturing cost can be reduced.

Hereinafter, a first example of a method for producing a composite substrate of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, a first substrate 1 having a plurality of terminals 4 (conductive portions) formed on one surface of a plate-like base material 3 is prepared.
Examples of the constituent material of the terminal 4 include one or more of copper, chromium, aluminum, nickel, titanium, titanium-tungsten alloy, and gold. Especially, it is preferable to use copper. The terminal 4 has a width of, for example, 50 μm or more and a thickness of, for example, 9 to 35 μm.

As shown in FIG. 2, a nonconductive resin film 7 is installed on the surface of the terminal 4.
As the non-conductive resin constituting the non-conductive resin film 7, a thermosetting resin such as an epoxy resin, a polyimide resin, a polyester resin, or a phenol resin may be used, or a thermoplastic resin such as an acrylic resin or a vinyl acetate resin. A resin may be used, but it is particularly preferable to use a thermosetting resin.
The non-conductive resin film 7 can be deformed according to the external force when an external force is applied, and preferably has surface adhesiveness.
The thickness of the nonconductive resin film 7 can be set to, for example, 20 to 100 μm.

The nonconductive resin film 7 preferably has an opening 8 at a position corresponding to a part of the surface of the terminal 4. The opening 8 is preferably formed in the center of the terminal 4, and the inner diameter thereof is made smaller than the outer diameter of the connecting particles 9. The inner diameter of the opening 8 is preferably 20 to 120 μm.
Hereinafter, the process of installing the nonconductive resin film 7 on the surface of the terminal 4 is referred to as a film installation process.

Next, as shown in FIG. 3, conductive connecting particles 9 are arranged on the surface of the terminal 4. A part of the connecting particles 9 is located in the opening 8.
As a constituent material of the connection particle 9, a metal material is preferable, and one or more of copper, chromium, aluminum, titanium, titanium-tungsten alloy, and gold can be used.
The connecting particles 9 may be made of a material having the same or lower melting point than the constituent materials of the terminals 4 and 6. For example, copper can be used for the terminals 4 and 6, and a material containing one or more of tin, zinc, and aluminum can be used for the connection particles 9.

The shape of the connection particle 9 is not particularly limited, but may be a substantially spherical shape, a substantially elliptical shape, a substantially cylindrical shape, a substantially polygonal column shape, a substantially conical shape, a substantially polygonal pyramid shape, a rectangular parallelepiped shape, or the like.
In particular, when a shape that makes point contact with the terminal 4, for example, spherical connecting particles 9, is used, the electrical resistance between the terminal 4 and the connecting particles 9 after the pressing step (described later) can be reduced.

The outer diameter of the connecting particle 9 is larger than the inner diameter of the opening 8. That is, the ratio of the inner diameter of the opening 8 to the outer diameter of the connecting particle 9 is less than 1. This ratio is preferably 0.8 or less.
By using the connecting particles 9 whose outer diameter is larger than the inner diameter of the opening 8, the connecting particles 9 are less likely to roll within the opening 8. For this reason, the displacement of the connecting particles 9 can be prevented, and the connecting particles 9 can be joined to the terminals 4 and 6 at accurate positions.
The ratio of the inner diameter of the opening 8 to the outer diameter of the connecting particle 9 is preferably 0.25 or more because the connecting particle 9 tends to be transferred from the opening 8 if it is too small.
When the diameter of the connecting particles 9 is 50 μm or more, for example, 50 to 200 μm, the electrical resistance between the terminals 4 and 6 and the connecting particles 9 after pressing can be reduced.

As shown in FIG. 3, in a state where the connecting particles 9 are arranged on the non-conductive resin film 7, the connecting particles 9 do not reach the terminals 4, but as shown in FIG. 4, the connecting particles 9 are connected to the terminals 4. By pressing until reaching, the contact area between the connection particles 9 and the non-conductive resin film 7 can be increased, and the connection particles 9 can be adhered to the non-conductive resin film 7. This makes it difficult for the connecting particles 9 to fall from the terminals 4.
Thus, the process of arrange | positioning the connection particle | grains 9 on the terminal 4 surface is called a connection particle | grain arrangement | positioning process.

As shown in FIG. 5, the 2nd board | substrate 2 with which the terminal 6 (electrically conductive part) was formed in one surface of the plate-shaped base material 5 is prepared. The second substrate 2 can have the same configuration as the first substrate 1.
The second substrate 2 is disposed so that the terminals 6 face the terminals 4, and the first and second substrates 1 and 2 are placed in a state where the connection particles 9 are sandwiched between the terminals 4 and 6 together with the non-conductive resin film 7. Press in directions approaching each other.
Pressing force 100 kgf / cm ² or more, is preferably 200 kgf / cm ² or less. 1 kgf corresponds to 9.80665N.
The temperature during pressing is 160 ° C or higher, preferably 240 ° C or higher. This temperature is preferably 300 ° C. or lower. The treatment time is preferably about 10 minutes.

As shown in FIG. 6, the connecting particles 9 are crushed in the pressing direction by pressing. In the illustrated example, the recesses 15 and 16 along the connection particles 9 are formed in the terminals 4 and 6, and the connection particles 9 are compressed in the pressing direction.
The connecting particles 9 are bonded to the terminals 4 and 6 in a strong and conductive manner by metal bonding or the like.
Hereinafter, the process of pressing the substrates 1 and 2 with the connecting particles 9 and the non-conductive resin film 7 sandwiched between the terminals 4 and 6 is referred to as a pressing process.

In the pressing step, the compression rate of the connection particles 9 (the amount of reduction in the size of the connection particles 9 due to compression relative to the size of the connection particles 9 before compression) is 30% or more, whereby the connection particles 9 and the terminals 4 and 6 Can be joined firmly. In addition, the dimension of the connection particle 9 means the dimension of a pressing direction.
By reducing the diameter of the connecting particles 9 to 2.5 to 6.5 times the thickness of the non-conductive resin film 7 and compressing the connecting particles 9 to the same thickness as the non-conductive resin film 7, the compression rate is 60-85%. Thereby, the connection particle 9 and the terminals 4 and 6 can be firmly joined. The compression rate is more preferably 75 to 85%.
The width of the connecting particles 9 after pressing can be the same as or smaller than the width of the terminals 4 and 6.

In the pressing step, the nonconductive resin film 7 has a shape corresponding to the connection particles 9 and the terminals 4 and 6.
That is, as the connecting particles 9 and the terminals 4 and 6 are deformed and the gap between them is reduced, the nonconductive resin is pushed away by the connecting particles 9 and the inter-terminal space 14 which is a space between the adjacent terminals 4 and 6. Into the insulating portion 19.
In the illustrated example, since the insulating portion 19 is formed around the connection particles 9 and the terminals 4 and 6 so as to surround them, the connection particles 9 and the terminals 4 and 6 can be shielded from the outside air to prevent corrosion.
Further, the bonding strength between the terminals 4 and 6 is further increased by the non-conductive resin between the peripheral portions 17 and 18 of the terminals 4 and 6, which are portions where the connection particles 9 are not interposed.
In the pressing step, when the extruded non-conductive resin fills the inter-terminal space 14, the insulation between the adjacent terminals 4 and 6 can be improved and the bonding strength of the substrates 1 and 2 can be further increased. .

When a thermosetting resin is used as the non-conductive resin, in the pressing step or after the pressing step, the non-conductive resin is cured by heating, and between the first substrate 1 and the second substrate 2. Bonding strength can be increased. The heating temperature can be, for example, 160 ° C. or higher.
For example, a non-conductive resin film 7 is formed using a semi-cured gel epoxy resin, and the pressing can be performed while heating the non-conductive resin film 7.
Through the above process, a composite substrate in which the first substrate 1 and the second substrate 2 are bonded is obtained.

  In the above manufacturing method, the non-conductive resin film 7 is installed on the terminal 4. However, the non-conductive resin film 7 may be installed on the surface of the terminal 6 or on both the terminals 4 and 6. May be.

In the above manufacturing method, the connecting particles 9 having an outer diameter larger than the inner diameter of the opening 8 are arranged in the opening 8 and the connecting particles 9 are crushed by pressing the substrates 1 and 2 and the non-conductive resin is pushed away. Thus, the terminals 4 and 6 are joined via the connection particles 9 so as to be conductive.
By using the connecting particles 9 whose outer diameter is larger than the inner diameter of the opening 8, the connecting particles 9 are less likely to roll within the opening 8. For this reason, the displacement of the connecting particles 9 can be prevented, and the connecting particles 9 can be joined to the terminals 4 and 6 at accurate positions.
Moreover, since the terminals 4 and 6 are joined by the crushed connecting particles 9, the conductivity between them can be increased.
Further, the insulating portion 19 made of the pushed non-conductive resin can enhance the insulation between the adjacent terminals 4 and 6 and can increase the bonding strength of the substrates 1 and 2.
In addition, the non-conductive resin can be easily and reliably disposed in the inter-terminal space 14 around the terminals 4 and 6, and the manufacturing process can be simplified and the manufacturing cost can be reduced.

In the above manufacturing method, since the connection particles 9 are sandwiched between the terminals 4 and 6 and the substrates 1 and 2 are pressed so as to be deformed, the electrical resistance between the terminals 4 and 6 and the connection particles 9 is reduced. While reducing, these joint strengths can be raised.
About the reason which can improve the electroconductivity and joining strength between the terminals 4 and 6 and the connection particle | grains 9, the following estimation is possible.
An oxide film may be formed on the surfaces of the terminals 4 and 6 and the connecting particles 9 due to the influence of oxygen in the air.
In the pressing step, when the terminals 4 and 6 and the connection particles 9 are deformed, the oxide film is broken, and the terminals 4 and 6 and the connection particles 9 are directly bonded to each other by a metal bond or the like without any oxide film interposed. It will be.
Therefore, the electrical resistance between them can be suppressed and the bonding strength can be increased.
Further, since the substrates 1 and 2 are bonded through the inexpensive connection particles 9, the cost can be reduced as compared with the case where an expensive anisotropic conductive film is used.

  In the composite substrate obtained by the above manufacturing method, a non-conductive resin may be interposed in a part of the boundary portions between the terminals 4 and 6 and the connection particles 9.

As shown in FIGS. 7 to 9, when the connection particles 9 are arranged on the non-conductive resin film 7, the fitting opening 10 having an inner diameter smaller than the outer diameter of the connection particles 9 is provided at a position corresponding to the terminal 4. A placement plate 11 having
For example, the connecting particles 9 are held in the non-conductive resin film in a state where the connecting particles 9 are held in the fitting port 10 by reducing the atmospheric pressure in the fitting port 10 of the arrangement plate 11 below atmospheric pressure by a decompression means (not shown). 7 can be used.

  As shown in FIGS. 10 and 11, when the connection particles 9 are arranged on the non-conductive resin film 7, the arrangement has a passage opening portion 20 through which the connection particles 9 can pass at a position corresponding to the terminal 4. A method of dropping the connection particles 9 onto the non-conductive resin film 7 through the passage opening 20 using the plate 21 can also be used.

By using the placement plates 11 and 21 having the fitting opening 10 or the passage opening 20 at a position corresponding to the terminal 4, the connecting particles 9 can be arranged at an accurate position with respect to the terminal 4.
The connecting particles 9 can also be supplied onto the non-conductive resin film 7 using a mounter that holds the connecting particles 9.

  In the above manufacturing method, one connection particle 9 is used for the pair of terminals 4 and 6, but a plurality of connection particles 9 can also be used.

Example 1
As the substrates 1 and 2, a copper clad laminate (PNS1018EEW manufactured by Nippon Steel Chemical Co., Ltd.) in which a copper foil (thickness 18 μm) was stretched on a base material 3 (thickness 25 μm) made of polyimide was used. . By etching this, terminals 4 and 6 having a width of 400 μm were formed.
A film mainly composed of an epoxy resin (NCF-F manufactured by Hitachi Chemical Co., Ltd.) is prepared as a non-conductive resin, and an opening 8 having a diameter of 80 μm is formed at a position corresponding to the terminals 4 and 6 with a UV-YAG laser. Formed. A non-conductive resin film 7 (thickness 50 μm) was formed by pasting this film on the terminals 4 and 6.
Spherical connecting particles 9 (diameter 200 μm) made of oxygen-free copper were placed in the opening 8 of the non-conductive resin film 7 of the substrate 1.
The board | substrate 2 was piled up on the board | substrate 1 so that the terminals 4 and 6 might face each other, and the board | substrates 1 and 2 were connected by pressing for 10 minutes by the temperature of 240 degreeC and the pressure of 100 kgf / cm < ² > using a press apparatus. The thickness of the connecting particles 9 after pressing was 60 μm.

A circuit board such as a printed wiring board can be applied to the composite board of the present invention. A semiconductor substrate can also be used.
The composite substrate of the present invention can be configured, for example, by joining two printed wiring boards. Moreover, it is good also as a structure provided with the printed wiring board and the semiconductor substrate, and good also as a structure which joined two semiconductor substrates.

It is process drawing explaining an example of the manufacturing method of the composite substrate of this invention. It is process drawing following a previous figure. It is process drawing following a previous figure. It is process drawing following a previous figure. It is process drawing following a previous figure. It is process drawing following a previous figure. It is process drawing explaining the other example of the manufacturing method of the composite substrate of this invention. It is process drawing following a previous figure. It is process drawing following a previous figure. It is process drawing explaining the further another example of the manufacturing method of the composite substrate of this invention. It is process drawing following a previous figure. It is a schematic block diagram which shows an example of the conventional composite substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st board | substrate, 2 ... 2nd board | substrate, 3, 5 ... Base material, 4, 6 ... Terminal (conductive part), 7 ... Nonelectroconductive resin film, 8 ... Opening part, 9 ... Connection particle, 10 ... Fit Joint part, 11, 21 ... Arrangement plate, 19 ... Insulating part, 20 ... Passing mouth part

Claims (6)

A method of manufacturing a composite substrate in which a pair of substrates having conductive portions are bonded to each other,
A film installation step of installing a non-conductive resin film having an opening on the surface of at least one of the pair of substrates and deformable by external force;
A connecting particle made of a conductive material and having an outer diameter larger than the inner diameter of the opening is arranged so that a part thereof is positioned in the opening of the non-conductive resin film, and the pair of substrates are arranged in a direction approaching each other. A pressing step of crushing the connecting particles by pressing and pressing the non-conductive resin to join the conductive portions through the connecting particles in a conductive manner. Production method.   The method of manufacturing a composite substrate according to claim 1, wherein the pushed non-conductive resin forms an insulating portion around the conductive portion.   The method of manufacturing a composite substrate according to claim 1, wherein the non-conductive resin is a thermosetting resin, and the non-conductive resin that has undergone the pressing step is cured by heating.   Using a placement plate having a fitting port part into which the connection particle can be fitted, and arranging the connection particles sandwiched between the conductive parts in the pressing step on the surface of the conductive layer in a state of being fitted to the fitting port part. The method for manufacturing a composite substrate according to any one of claims 1 to 3.   Using an arrangement plate having a passage opening portion through which the connection particles can pass, and connecting particles sandwiched between the conductive portions in the pressing step are arranged on the surface of the conductive layer by dropping from the passage opening portions. The manufacturing method of the composite substrate of any one of Claims 1-3. A composite substrate in which a pair of substrates having conductive portions are bonded to each other,
The pair of substrates, the connecting particles that are compressed between the conductive portions of the substrates and bonded to each other so as to be conductive, and the non-conductive resin formed on the surface of the conductive portions are pressed and deformed to surround the conductive portions. And an insulating part formed on the substrate.

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