JP2005260138A - Board device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the reliability of connection between wired rigid boards is not constant when the boards are connected electrically to each other. <P>SOLUTION: The rigid board 21 on which a semiconductor integrated circuit 23 is mounted, and a rigid board 26 on which a semiconductor integrated circuit 28 is mounted, are stuck together in face to face with each other, and are connected electrically via connection 32 to form a board device. The board device has a protrusion electrode 25 formed on the rigid board 21, and an electrode 30 formed at a specific position on the rigid board 26 so as to be faced to the projecting electrode 25. A thermosetting adhesive resin 31 is inserted between the electrodes 25, 30, and is heated and pressurized to glue the rigid boards 21, 26 together. In this manner, the reliability of connection between the boards 21, 26 is improved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a substrate device on which an electronic circuit such as a semiconductor integrated circuit is mounted.

  Hereinafter, a conventional substrate apparatus will be described. In FIG. 6, reference numeral 1 denotes a rigid substrate in which a recess (cavity) 2 is formed, and a semiconductor integrated circuit 3 is mounted in the recess 2. And the electrode 5 is formed in the convex part 4 which forms the outer periphery of this recessed part 2. As shown in FIG. Similarly, a recess 7 is also formed in the rigid substrate 6 bonded to the rigid substrate 1, and a semiconductor integrated circuit 8 is mounted in the recess 7. And the electrode 10 is formed in the convex part 9 which forms the outer periphery of this recessed part 7. FIG. FIG. 7 is a view of the substrate 1 side of FIG. 6 as viewed from below.

  The electrodes 5 and 10 are electrically and mechanically connected by an anisotropic conductive film 11 to exchange signals between the semiconductor integrated circuit 3 and the semiconductor integrated circuit 8.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP-A-11-284030

However, the technique of Patent Document 1 is disadvantageous in terms of tact and cost because it is necessary to provide a recess in the anisotropic conductive film on the connection electrode in advance, and a process is added. Also,
A high degree of mounting accuracy is also required to control the position and height of the recess, and there is a problem in practical use.

  If the conductive adhesive layer (anisotropic conductive film or anisotropic conductive paste) is thickened to increase the connection reliability when the substrates are electrically connected to each other, the anisotropic conductive film itself is connected at the time of connection. It has a repulsive force against the pressing force, and an excessive pressing force is required. In some cases, pressure shortage occurs, resulting in poor connection (open / high resistance). Furthermore, an excess anisotropic conductive film may protrude from the end face of the substrate and contaminate the end face of the substrate. On the other hand, when the conductive layer becomes thin, poor connection occurs due to insufficient adhesion between the substrates due to insufficient conductive film, and reliability decreases.

  Accordingly, an object of the present invention is to provide an inexpensive, more practical and highly reliable substrate connecting apparatus.

  In order to achieve this object, the connecting portion of the substrate device of the present invention includes a protruding electrode provided on at least one rigid substrate and an electrode provided at a corresponding position on the other rigid substrate so as to face the protruding electrode. The rigid substrates are bonded to each other by inserting a thermosetting adhesive resin between the electrodes, heating and applying pressure. As a result, the pitch of the substrate device can be reduced, so that the substrate device can be reduced in size.

  According to a first aspect of the present invention, a first rigid substrate on which a first circuit is formed and a second rigid substrate on which a second circuit is formed are provided to face each other, and A substrate device in which first and second rigid substrates are electrically connected to each other via a connecting portion, wherein the connecting portion is opposed to the protruding electrode provided on at least one rigid substrate. And an electrode provided at a corresponding position of the other rigid substrate, and a thermosetting adhesive resin is inserted between the electrodes, heated, and pressure is applied to bond the rigid substrates together It is adhesion by heating and applying pressure between the electrodes, and it is connected by contact bonding between solids, so that the solder melts and becomes liquid as in the past and connects to the adjacent electrode Never do. Therefore, the distance between the electrodes can be reduced, and the pitch of the electrodes can be reduced. That is, the substrate device can be downsized.

  Invention of Claim 2 is a board | substrate apparatus of Claim 1 which used the anisotropic conductive film as a thermosetting adhesive resin, and since the anisotropic conductive film is used, the function of conductive particles This ensures connection between the electrodes. Moreover, work becomes easy by using an anisotropic conductive film (film shape).

  Invention of Claim 3 is a board | substrate apparatus of Claim 1 which used anisotropic conductive paste as a thermosetting adhesive resin, and since anisotropic conductive paste is used, the function of conductive particles This ensures connection between the electrodes. Further, since the anisotropic conductive paste is used, printing becomes possible and the number of manufacturing steps can be reduced.

  According to a fourth aspect of the present invention, the initial height of the protruding electrode forming the connecting portion is set to be larger than a value obtained by adding 10 μm to the sum of the surface roughness of the electrode laying surface forming the connecting portion. The electrodes are surely connected to each other even if the electrode laying surface is warped or wavy.

  The protruding electrode of the invention described in claim 5 is the substrate device according to claim 4 which is deformed by applying a constant pressure. For example, even if the electrode laying surface is warped or wavy, the protruding electrode is maintained at a constant pressure. Since the electrodes are deformed, all the electrodes can be reliably connected to each other, and connection failure does not occur.

  In the invention described in claim 6, the initial thickness of the thermosetting adhesive resin is larger than the value obtained by adding 10 μm to the height of the bump electrode after pressure contact, and 30 μm is added to the height of the bump electrode after pressure contact. The substrate device according to claim 1, wherein the substrate device is smaller than the value, and even if there is warping or waviness on the electrode laying surface, it can be securely bonded with a thermosetting adhesive resin, resulting in poor contact and connection strength. There is no decline. In addition, there is no problem such as protrusion due to excessive thermosetting adhesive resin.

  According to a seventh aspect of the present invention, a recess is formed in at least one of the first rigid substrate and the second rigid substrate, and a semiconductor integrated circuit is mounted in the recess to form an outer periphery of the recess. 2. The substrate device according to claim 1, wherein the connecting portion is provided on the convex portion, and the connection pitch can be narrowed even if the number of terminals of the semiconductor integrated circuit is large, so that a small substrate device can be realized.

  As described above, according to the present invention, a protruding electrode having an appropriate height is selected with respect to warping and undulation of the substrate, and a conductive adhesive resin having an appropriate thickness is selected between the electrodes, and heat and pressure are selected. Is added to increase the reliability of connection between the substrates, and an unnecessary conductive film does not protrude from the end surfaces of the substrates. Accordingly, it is possible to reduce the pitch and size of electrodes of a substrate device, and to obtain a device that can obtain a highly reliable connection and that is not contaminated by excessive protrusion of the conductive film to the end surface of the substrate. Can do.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a substrate device in Embodiment 1 of the present invention. In FIG. 1, reference numeral 21 denotes one rigid substrate, which is composed of a ceramic multilayer substrate. A convex portion 24 is formed by further laminating a ceramic multilayer substrate on the outer periphery of the rigid substrate 21. Therefore, a recess 22 is formed in the central portion of the rigid substrate 21. A semiconductor integrated circuit (IC) 23 is mounted in the concave portion 22, a protruding electrode 25 is provided on the convex portion 24, and a wiring pattern and an inner side are connected from a terminal of the semiconductor integrated circuit 23 through the rigid substrate 21 and the convex portion 24. Connected with vias.

  Similarly, reference numeral 26 denotes the other rigid substrate, and this rigid substrate 26 is laminated to form a recess 27 in the central portion. A semiconductor integrated circuit 28 is mounted in the recess 27. Reference numeral 29 denotes a convex portion that forms the outer periphery of the concave portion 27, and a flat electrode (receiving electrode) 30 is provided on the convex portion 29, and wiring is provided from the terminal of the semiconductor integrated circuit 28 through the rigid substrate 26 and the convex portion 29. It is connected to the pattern with an inner via.

  31 is a thermosetting conductive adhesive resin, and the protruding electrode 25 and the electrode 30 form a connection portion 32 to connect the protruding electrode 25 and the electrode 30. Further, the protruding electrode 25 and the electrode 30 are electrically and mechanically connected at the connection portion 32, so that the concave portions 22 and 27 are joined together to form a closed space (cavity) 33. Semiconductor integrated circuits 23 and 28 are mounted therein. The terminal signals of the semiconductor integrated circuits 23 and 28 are guided to and connected to the connection portions 32 by the wiring patterns in the rigid substrates 21 and 26 and the convex portions 24 and 29 and the inner vias connecting the layers.

Next, the connection part 32 is demonstrated based on FIG. In FIG. 2, the protruding electrode 25 is made of a material that is easily deformed by a certain pressure, such as gold (Au) or silver (Ag). Further, the protruding electrode 25 has a terminal diameter of 500 μm or less, and is deformed by applying a certain pressure, so that the protruding electrode 25 is connected to the opposing electrode 30.
In this embodiment, an anisotropic conductive film (ACF) 31a in which conductive particles such as gold, silver, and copper are dispersed in an adhesive resin to form a film is used as the thermosetting conductive adhesive resin 31. Yes. Since this has conductive particles, the electrical connection between the electrodes 25 and 30 can be ensured. Further, the anisotropic conductive film 31a is in the form of a film, and the work becomes easy.
An anisotropic conductive paste (ACP) 31b can also be used as the thermosetting adhesive resin 31. Also in this case, since the conductive particles are included, the electrical connection between the electrodes 25 and 30 can be ensured. Further, since the anisotropic conductive paste 31b is in a paste form and can be printed, the number of manufacturing steps can be reduced.

  The thermosetting adhesive resin 31 may be a film-like NCF or a paste-like NCP that does not contain conductive particles. In this case, since the conductive particles are not included, it is possible to further reduce the pitch. In the present embodiment, the distance 37 between adjacent electrodes is set to 100 μm using the anisotropic conductive film 31a. However, in the anisotropic conductive film 31a and the anisotropic conductive paste 31b, the distance 37 between adjacent electrodes can be set to a narrow pitch of about 60 μm. If NCF or NCP that does not contain conductive particles is used, the distance 37 between adjacent electrodes can be set to a narrow pitch of about 40 μm, and further miniaturization can be realized.

  FIG. 3 is a relationship diagram of temperature and pressure applied to the protruding electrode 25, the electrode 30, and the thermosetting adhesive resin 31 when the protruding electrode 25 and the electrode 30 are bonded. The horizontal axis 41 is time, the left vertical axis 42 is temperature, and the right vertical axis 45 is pressure. Reference numeral 43 is a temperature curve, and 44 is a curve showing a change in pressure.

  The heating temperature starts at 60 ° C. and reaches 200 ° C. over 30 seconds (43a). Next, this state is maintained for 30 seconds (43b), and the heating is finished. After that, naturally cool to room temperature. Further, as indicated by the dotted line 44, the pressure at that time is pressurized to 75 g (per electrode) at a stroke (about 2 to 3 seconds) (44a) and kept in this state for about 80 to 90 seconds ( 44b), and then pressurization is terminated (44c). In this embodiment, the pressure is 75 g per electrode. However, this is only an example, and a good connection can be achieved if the pressure is 50 g to 150 g per electrode.

  Since the recesses 24 and 29 are formed by firing a ceramic multilayer substrate, warping and undulation occur after firing. FIG. 4 shows the degree of surface roughness (flatness) of the electrode laying surfaces 35 and 36 when the electrode laying surfaces 35 and 36 formed on the protrusions 24 and 29 are warped or swelled during firing, and the electrodes (in this case). Shows the relationship with the protruding electrode 25) and the relationship with the thermosetting adhesive resin 31.

  It is important that 51 be the height H1 of the protruding electrode 25 and 52 and 53 be the maximum surface roughness values Ry1 and Ry2 of the electrode laying surfaces 35 and 36, respectively, so that the relationship shown in (Equation 1) holds. .

If the height of the protruding electrode is less than or equal to the maximum value of the surface roughness of each rigid substrate, the connection terminals of both substrates cannot contact each other, resulting in poor connection. When the value is higher than the maximum value, the protruding electrode 25 may not be pushed into the terminal 30. In this case, the protruding electrode 25 does not break through the resin 31 film, and a thin resin film is interposed at the interface, resulting in a decrease in reliability. Therefore, when the height H1 of the initial protruding electrode 25 forming the connection portion 32 satisfies the relationship of (Equation 1), it is assumed that the electrode laying surfaces 35 and 36 of the rigid substrates 21 and 26 have warpage and undulation. However, the electrodes 25 and 30 are reliably connected to each other, and the protrusion electrode can be sufficiently pushed in, so that an ideal pressure contact state can be obtained.
Reference numeral 54 denotes an initial thickness T of the thermosetting adhesive resin 31, and it is important to satisfy the relationship shown in (Expression 2) with the height H2 of the protruding electrode 25 after press contact as shown in FIG. It is.

If T is thinner than 10 μm, the adhesive force due to insufficient resin is reduced between the substrate and the conductive film, resulting in poor connection conduction (open / high resistance). On the other hand, when T is thicker than 30 μm, the conductive film itself becomes a resistance, resulting in poor conduction due to insufficient pressure, and contamination due to protrusion of the resin to the end face of the substrate.
Therefore, when the initial thickness T of the thermosetting adhesive resin 31 satisfies the relationship of (Equation 2), even if the laying electrode surfaces 35 and 36 are warped or wavy, the thermosetting adhesive resin 31 is used. Can be securely bonded. Therefore, there is no contact failure or connection strength reduction. In addition, there is no problem such as insufficient pressure or protrusion due to excessive thermosetting adhesive resin 31.

  As shown in FIG. 1, the substrate apparatus according to the present embodiment forms recesses 22 and 27 in both the rigid substrate 21 and the rigid substrate 26, and the inside of the closed space 33 formed by the recesses 22 and 27. In addition, the semiconductor integrated circuits 23 and 28 are mounted, respectively. Further, the connection portions 32 are provided on the projections 24 and 29 that form the outer circumferences of the recesses 22 and 27, and the protruding electrodes 25 and the electrodes 30 are electrically connected and bonded together with a thermosetting connection resin 31, respectively. Configure the device. With this configuration, even when the number of terminals of the semiconductor integrated circuits 23 and 28 is increased, the connection pitch can be reduced, so that a small substrate device can be realized.

  Since the substrate device according to the present invention can be connected at a narrow pitch, it is particularly useful for downsizing a module component or the like incorporating a semiconductor integrated circuit.

Sectional drawing of the board | substrate apparatus in one embodiment of this invention Same part cross section Same figure of temperature and pressure Cross section showing the relationship between electrode and flatness Cross section showing the relationship between electrode and thermosetting adhesive resin Sectional view of a conventional substrate device Same as above, top view

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 Rigid board | substrate 23 Semiconductor integrated circuit 25 Projection electrode 26 Rigid board | substrate 28 Semiconductor integrated circuit 30 Electrode 31 Anisotropic conductive resin 32 Connection part

Claims (7)

A first rigid substrate on which a first circuit is formed and a second rigid substrate on which a second circuit is formed are provided to face each other, and the first and second rigid substrates are connected to each other. The connection device is provided with a protruding electrode provided on at least one rigid substrate and a corresponding position on the other rigid substrate facing the protruding electrode. A substrate device in which the rigid substrates are bonded to each other by inserting a thermosetting adhesive resin between the electrodes, heating and applying pressure. The substrate device according to claim 1, wherein an anisotropic conductive film is used as the thermosetting adhesive resin. The substrate apparatus according to claim 1, wherein an anisotropic conductive paste is used as the thermosetting adhesive resin. The substrate apparatus according to claim 1, wherein the initial height of the protruding electrode forming the connection portion is larger than a value obtained by adding 10 μm to the sum of the surface roughness of the electrode mounting surface forming the connection portion. The substrate device according to claim 4, wherein the protruding electrode is deformed by applying a constant pressure. The initial thickness of the thermosetting adhesive resin is set to a value larger than a value obtained by adding 10 μm to the height of the protruding electrode after press contact and smaller than a value obtained by adding 30 μm to the height of the protruding electrode. Board device. A concave portion is formed on at least one surface of the first rigid substrate and the second rigid substrate, a semiconductor integrated circuit is mounted in the concave portion, and a connecting portion is provided on the convex portion forming the outer periphery of the concave portion. The substrate device according to claim 1.

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