JPH11163225A - Relay board, connection body between ic mounting board relay board, and structure composed of ic mounting board, relay board, and mounting board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a relay board and a connection body between an IC mounting board and the relay board, which are capable of canceling nonuiformity in thermal expansion coefficients caused by a thermal expansion coefficient difference between the IC mounting board mounted with an IC chip and a mounting board, so as to be enhanced in connection reliability and furthermore to obtain a structure which is high in connection reliability and composed of an IC mounting board, a relay board, and a mounting board. SOLUTION: A relay board consists of a nearly plate-like relay board body 1 which is formed of a glass-epoxy resin composite material and possesses a first surface 1a and a second surface 1b, a first surface terminal 6 formed on the first surface 1a, and a second surface terminal 7 formed on the second surface 1b at a position corresponding to the first terminal 6, so as to be electrically connected to the first surface terminal 6. A part of the relay board body 1 corresponding to an IC chip is set lower in glass fiber content than the other part of the relay board body so as to be larger in thermal expansion coefficient than the other part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC mounting board on which an integrated circuit chip is mounted, and more particularly, to a relay board interposed between an IC mounting board made of a resin-containing material such as a glass-epoxy resin composite material and a mounting board. The present invention relates to a connection body between an IC mounting board and a relay board, and a structure including an IC mounting board, a relay board, and a mounting board.

[0002]

2. Description of the Related Art Conventionally, when a pad formed on the main surface of one substrate and a pad formed on the main surface of the other substrate having a different coefficient of thermal expansion are connected to each other, the distance between the two substrates is increased. In addition, there is known a device in which a relay board is interposed to reduce stress caused by a difference in thermal expansion coefficient.

For example, in the connection structure of boards disclosed in Japanese Patent Publication No. 2-45357, a relay board 215 as shown in FIG. 22A is disclosed. The relay substrate 215 has a copper conductor 219 formed by plating in a through hole formed in the relay substrate main body 210 made of alumina, and a solder electrode 212 made of high-temperature solder of Pb 95% -Sn 5%. The through-hole electrode 214 is formed. This relay board 215 is interposed between a silicon board (silicon chip) 211 and a printed board 218 made of glass epoxy as shown in FIG. The connection is prevented from being destroyed.

Such a relay board is used not only for connecting a silicon chip to a printed board made of resin, but also for example, as disclosed in Japanese Patent Application Laid-Open No. 61-3497. There is also an example in which it is interposed between a substrate and an organic printed board. That is, JP-A-61-3
No. 497 discloses a joining frame (relay substrate main body) 225 made of polyurethane resin or the like between a ceramic substrate 222 and an organic printed board 221 as shown in FIG.
Between the pad 229 of the ceramic substrate 222 and the pad 226 of the organic printed circuit board 221.
A connection using a low melting point metal 227 such as b is disclosed. In the prior art described above, a relay board is used to reduce the difference in coefficient of thermal expansion between a silicon chip or a wiring board and an organic printed board made of glass epoxy or the like. Were highly rigid and hardly deformed, such as a silicon chip or a ceramic wiring board.

[0005]

However, due to the recent technological progress, a wiring board using a high-performance resin or a composite material of a resin and glass fiber has appeared, and an integrated circuit chip (hereinafter simply referred to as an IC chip) has been developed. ) Is mounted on such a wiring board, and an IC mounting board has been used. In a wiring board using such a resin,
In general, there are advantages that the dielectric constant of the resin is smaller than that of ceramics or the like, which is convenient for transmitting a high-frequency signal, and that processing is easy and baking at a high temperature is unnecessary.

Also, since the thermal expansion coefficient is almost the same as that of an organic printed circuit board made of glass epoxy or the like, even if both are connected, the stress due to the difference in the thermal expansion coefficient is very small. Does not grow. Therefore, it was considered unnecessary to interpose a relay board between such an IC mounting board and the organic printed board.

However, for example, as shown in FIG. 24A, when the wiring board main body 301 is made of a material containing a resin such as a glass-epoxy resin composite material, the upper surface (first
Since the IC chip 311 mounted on the (surface) is made of Si, the coefficient of thermal expansion is small (α = 3 to 4 × 10 ⁻⁶ / ° C.).
= 10 to several tens × 10 ⁻⁶ / ° C. It is significantly different from the coefficient of thermal expansion of a material containing a resin. Further, since a material containing a resin is softer (lower in rigidity) than a ceramic or the like, for example, as shown in FIG.
The area where the C chip 311 is mounted tends to be warped so as to be convex downward, and each solder ball 303 receives stress that expands and contracts in the vertical direction. Note that the deformation shown in FIG. 24 (a) emphasizes the amount of deformation, and in practice, the eutectic solder ball 303 is hard to deform, so the amount of deformation is very small. Therefore, the stress causing such deformation causes the solder ball 303 to fatigue.
Finally, as shown in FIG. 24B, of the solder balls 303 formed at positions (IC chip corresponding positions) corresponding to the positions where the IC chips 311 are mounted, the connection pads 302 and the mounting pads It has been found that a crack K1 or K2 as shown by a broken line occurs in a portion near 322, which causes a failure to be selectively broken.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an IC chip and an IC mounting board for mounting the IC chip between a mounting board and an IC mounting board made of a material containing resin. Caused by the difference in the coefficient of thermal expansion between
A relay board that cancels non-uniformity of the coefficient of thermal expansion and obtains high connection reliability with the mounting board, a connection body between the IC mounting board and the relay board, and a mounting with the IC mounting board and the relay board with high connection reliability An object of the present invention is to provide a structure including a substrate.

[0009]

Means and effects for solving the problems First, claim 1
The present invention provides an IC mounting substrate body having a substantially plate shape having a main surface and a back surface and made of a material containing a resin, an integrated circuit chip mounted on the main surface side, and at least the An IC mounting substrate including a connection pad formed at a position corresponding to the integrated circuit chip; a mounting substrate body; and a main surface of the mounting substrate body formed at a position corresponding to the connection pad of the IC mounting substrate. Between the IC mounting board and the mounting board by connecting the connecting pad on the first surface side and connecting to the mounting pad on the second surface side. A relay board body having a substantially plate shape having the first surface and the second surface, the relay board body being made of a material including a resin, and a relay board formed on the first surface side. 1
A surface side terminal, and a second surface side terminal formed at a position corresponding to the first surface side terminal of the second surface side and electrically connected to the first surface side terminal; A relay board characterized in that the other part of the board body has a smaller coefficient of thermal expansion than the part corresponding to the integrated circuit chip.

[0010] The IC mounting substrate main body has a portion (hereinafter, referred to as an IC) on which an integrated circuit chip (hereinafter, also referred to as an IC chip) is mounted.
C), the thermal expansion coefficient is relatively small compared to a part where the IC chip is not mounted (hereinafter, also referred to as an IC non-mounting part) because it is constrained by an IC chip having a low thermal expansion coefficient (hereinafter also referred to as an IC non-mounting part). Lowered). For this reason, warpage deformation occurs as described above. On the other hand, in the relay board of the present invention having the above configuration, the thermal expansion coefficient of a portion (hereinafter, also referred to as an IC chip corresponding portion) corresponding to the integrated circuit chip in the relay substrate body is different from that of the other portion ( (Hereinafter, it is also referred to as an IC chip non-corresponding portion.)

Here, when the IC mounting board and the relay board are connected, the IC mounting portion of the IC mounting board main body and the IC chip corresponding portion of the relay board main body are connected so as to correspond to each other. In addition, the non-IC mounting portion of the IC mounting substrate body and the non-IC chip corresponding portion of the relay substrate main body are connected so as to correspond to each other. Looking at the coefficient of thermal expansion of the connection body between the IC mounting board and the relay board, the IC mounting portion is small,
The part corresponding to the chip is large. Therefore, the coefficient of thermal expansion of the IC mounting portion is increased by the influence of the coefficient of thermal expansion of the portion corresponding to the IC chip. On the other hand, the part without IC is large,
The portion that does not correspond to the chip is small. Therefore, the coefficient of thermal expansion of the non-IC-mounted portion is reduced by the influence of the coefficient of thermal expansion of the non-IC chip-corresponding portion.

That is, in any part, the coefficients of thermal expansion are in opposite relations to each other.
The difference in the coefficient of thermal expansion in the mounting board or relay board is
It will be in the state canceled mutually. Therefore, when such a relay board is connected to the IC mounting board (when the connecting body between the IC mounting board and the relay board is used), even if this is further connected to the mounting board, the warpage due to the influence of the IC chip. Defects such as deformation and breakage at the connection portion do not occur, and high connection reliability can be obtained.

Here, examples of the material containing a resin include those using a resin such as epoxy, polyimide, BT, polyurethane, or a composite material with these resins.
Examples of the composite include a composite of a resin represented by a glass-epoxy resin composite and a fiber such as glass or polyethylene, a composite of a resin and a ceramic powder, and the like. Further, the material of the integrated circuit chip mounted on the main surface side of the IC mounting substrate main body is mostly silicon, but may be gallium arsenide or the like.

As a method of mounting the integrated circuit chip on the main body of the IC mounting substrate, the connection with the IC mounting substrate may be performed by a flip-chip method or by a die attach method. Further, when the integrated circuit chips are connected by the flip chip method, an underfill for injecting and fixing a resin between the IC mounting substrate body and the integrated circuit chips may be performed thereafter. In addition, connection pads for connecting to the mounting board are formed on the back surface of the IC mounting board body. As an example of the arrangement of the connection pads, a lattice shape can be cited, but the connection pads need not necessarily be arranged in a lattice shape. Further, bumps may be formed by raising solder on the connection pads.

The mounting board is a board for mounting an IC mounting board, and includes a printed board such as a motherboard. The material of the mounting board body is glass
Composite materials of resins such as epoxy, polyimide, BT, and polyurethane and fibers such as glass and polyester, represented by epoxy resin composite materials, and composite materials of these resins and ceramic powder, alumina, mullite, aluminum nitride, etc. Ceramic. Mounting pads for mounting the IC mounting board are formed on the main surface of the mounting board body. This mounting pad is a pad provided on the mounting substrate body for electrical connection with the IC mounting substrate. A specific example of the mounting board is a printed circuit board in which mounting pads are arranged in a grid pattern. However, the mounting pads may not necessarily be arranged in a grid pattern. A plurality of mounting pad groups corresponding to the substrate may be provided. In addition, bumps may be formed by raising solder on each mounting pad.

In the present invention, the relay board main body is
Of the two substantially plate-shaped surfaces, the side connected to the IC mounting board is referred to as a first surface, and the side connected to the mounting board is referred to as a second surface for convenience.

The first surface side terminal is a terminal formed on the first surface side of the relay board main body, and indicates a terminal for connecting to a connection pad of the IC mounting board. In addition, as a specific formation place of the first surface side terminal, a terminal formed on the first surface of the main body may be cited, but is not limited thereto.
For example, lower than the first surface (lower inside the relay board body)
May be formed on the bottom surface of the concave portion, or may be formed so as to rise from such a concave portion beyond the first surface. Further, the first surface side portion of the soft metal body formed by being inserted into the through hole formed in the main body may be used as the first surface side terminal.

Similarly, the second surface side terminal is a terminal formed on the second surface side of the relay board main body and refers to a terminal for connecting to a mounting pad of the mounting board. In addition, as a specific formation place of the second surface side terminal, there is one formed on the second surface of the main body, but it is not limited to this. For example, it may be formed on the bottom surface of the concave portion lower than the second surface (lower inside the relay board main body), or may be formed so as to rise from such a concave portion beyond the second surface.
Further, the second surface side portion of the soft metal body formed to pass through the through hole formed in the main body may be used as the second surface side terminal. Further, the first surface side terminal and the second surface side terminal are electrically connected, and specifically, both are electrically connected by a through-hole conductor or a via formed in the relay board main body. Also, electrical connection can be made when a soft metal body is inserted into a through hole formed in the relay board main body.

The portion of the relay substrate body corresponding to the integrated circuit chip (portion corresponding to the IC chip) is defined as a portion of the relay substrate body above the first surface in the thickness direction of the relay substrate body.
Refers to a portion of the C mounting board where the integrated circuit chip is located. This part is usually located almost at the center of the relay board main body, but is not limited to the center. Also,
For example, when connecting to an IC mounting board on which a plurality of IC chips are mounted, there may be a case where a plurality of IC chip corresponding portions can be provided corresponding to each IC chip.

Further, the thermal expansion coefficient of the other portion (the portion not supporting the IC chip) of the relay substrate body is the thermal expansion coefficient of the portion of the IC mounting substrate on which the integrated circuit chip is not mounted (the non-IC mounting portion). It should be smaller than the rate. Since the coefficient of thermal expansion of the non-IC-mounted portion is reduced by the non-IC chip-corresponding portion, the difference from the coefficient of thermal expansion of the IC-mounted portion is small or eliminated, and warpage due to uneven thermal expansion coefficient is suppressed. Therefore, higher connection reliability can be obtained.

Further, a solution according to a second aspect is the relay board according to the first aspect, wherein the relay board main body is made of a resin and fibers having a smaller coefficient of thermal expansion than the resin. A main body fiber made of at least one of glass fiber and organic fiber, and the other portion of the relay substrate main body is more of the main body fiber than the portion corresponding to the integrated circuit chip. A relay board characterized by having a high content.

According to the relay board of the present invention having the above structure, the main body of the relay board mainly includes the resin and the fibers for the main body. The thermal expansion coefficient of such a composite material is a composite value of the thermal expansion coefficient of the resin and the thermal expansion coefficient of the body fibers. This is because the deformation due to the difference in the coefficient of thermal expansion is mutually restricted. That is, when the thermal expansion coefficient of the fiber for the main body is smaller than that of the resin, when the content of the fiber for the main body increases, the thermal expansion coefficient of the entire composite material decreases. This is because the higher the content of the main body fiber, the more the fiber restricts the thermal expansion of the resin. Therefore, if the fiber for the main body is included more in the other part (the part not corresponding to the IC chip) than in the part corresponding to the integrated circuit chip (the part corresponding to the IC chip), the heat is relatively increased in the part corresponding to the IC chip. The coefficient of expansion decreases.

The fibers for the main body include glass fibers and organic fibers such as polyester and nylon.

According to a third aspect of the present invention, there is provided a relay board according to the first or second aspect, wherein the other portion of the relay board body corresponds to the integrated circuit chip. And a low-thermal-expansion plate having a lower coefficient of thermal expansion than the coefficient of thermal expansion of the portion to be connected.

In the relay board of the present invention having the above structure, the relay board main body is made of a material containing a resin, and the non-IC chip non-corresponding portion of the relay board main body is provided with the low thermal expansion plate. In this case, the thermal expansion coefficient is relatively reduced by being restrained by the low thermal expansion plate.
The portion corresponding to the chip can be made relatively large without changing the coefficient of thermal expansion.

Here, as the low thermal expansion plate, any plate may be used as long as it has a lower coefficient of thermal expansion than the portion corresponding to the integrated circuit chip (the portion corresponding to the IC chip). Examples include ceramics and metals having a low coefficient of thermal expansion. Examples of the ceramic include aluminum nitride, mullite, sialon, and the like, in addition to alumina. On the other hand, when metal is used, it can be processed by punching or drilling, and so processing is easy.
Specific examples of the metal having a low coefficient of thermal expansion include 42 alloy, Kovar, Invar, molybdenum, tungsten, CIC (copper / invar / copper clad material), and the like.

According to a fourth aspect of the present invention, there is provided the relay board according to the third aspect, wherein the low thermal expansion plate comprises:
A relay board made of an insulating ceramic.

In the relay board of the present invention having the above-described structure, an insulating ceramic is used for the low thermal expansion plate. When using an insulating ceramic, a short circuit occurs between the first and second surface side terminals and the low thermal expansion plate, or between the wiring between the first surface side terminal and the second surface side terminal and the low thermal expansion plate. Since there is no need to worry and the insulation can be maintained, there is no need to adopt a structure that takes into consideration the insulation between the terminals and the wiring between the terminals, and the structure can be simple and easy to manufacture.

[0029] Further, the relay board may be formed as follows.
The relay substrate according to any one of the above, wherein the second surface side terminal is made of a soft metal, and has a substantially columnar shape having a height in the axial direction higher than a maximum diameter thereof, Good to do. In this case, since the second surface side terminal is substantially columnar, even after connecting the relay board to the IC mounting board, the deformation occurring at the time of heating / cooling is prevented by the expansion and contraction of the second surface side terminal. Since it can be absorbed by deformation or bending deformation, higher connection reliability can be obtained.

The soft metal refers to a soft metal, and when subjected to stress, easily deforms to release the stress. Specific materials include lead (Pb), tin (Sn), zinc (Zn), and alloys containing these as main components, for example, Pb-S
Examples include n-based high-temperature solder (for example, Pb 90% -Sn 10% alloy, Pb 95% -Sn 5% alloy, etc.), Pb-Sn eutectic solder (Pb 36% -Sn 64% alloy), white metal, and the like. Since lead, tin and the like have a recrystallization temperature of room temperature, they recrystallize even if they undergo plastic deformation. Therefore, even if repeated stress is applied, it does not easily break (break), which is convenient.

Furthermore, the substantially columnar terminal only needs to have a substantially columnar shape whose height is higher than its maximum diameter, and its outer shape may be such that its diameter varies in the height direction. For example, a barrel-like shape with a large diameter at the center,
The central portion may have a small diameter (the central portion is constricted) or a tapered shape. Further, it may have a prismatic shape such as a quadrangular prism or a triangular prism. However, in order to avoid concentration of stress at the corners, among them, those having a large number of corners such as a hexagonal prism and an octagonal prism are preferable, and a cylindrical shape is more preferable. Furthermore, it is preferable that the height of the columnar terminal be twice or more the maximum diameter, because the columnar terminal can be easily deformed. Further, the tip surface may be a hemispherical surface, but may be a flat surface or a surface having a concave portion in order to prevent a shift from occurring when connected to the mounting pad.

According to a fifth aspect of the present invention, there is provided an IC wherein the relay board according to any one of the first to fourth aspects is connected to the IC mounting board.
It is a connection body between the mounting board and the relay board.

The connection body of the present invention having the above structure is an IC
Looking at the coefficient of thermal expansion of the mounting board and relay board, IC
The mounting part (the part on which the IC chip is mounted) is small.
The portion corresponding to the C chip (the portion corresponding to the integrated circuit chip) is large. On the other hand, the non-IC mounted portion (the portion on which the IC chip is not mounted) is large, and the non-IC chip compatible portion (the other portion) is small. That is, the coefficients of thermal expansion are in a relationship opposite to each other, and when viewed as a whole of the connected body connecting the IC mounting board and the relay board, they are constrained to each other, and the magnitudes of the coefficients of thermal expansion are canceled each other. It can be substantially constant. Therefore, such a connection body does not cause warpage deformation or the like as a whole, or can be reduced.
High connection reliability can be obtained in connection with the mounting board.

Further, a solution according to a sixth aspect of the present invention is a connecting body between the IC mounting board and the relay board according to the fifth aspect, wherein:
A connection body between an IC mounting board and a relay board, characterized by being filled with an insulating resin for connecting the two.

The connecting body of the present invention having the above-described structure is an IC
An insulating resin is filled between the mounting board main body and the relay board main body, and both are connected. For this reason, since the IC mounting board main body and the relay board main body are more firmly integrated by the insulating resin, deformation of the whole connection body between the IC mounting board and the relay board is prevented, and the height of the mounting board is higher. Connection reliability can be obtained.

Further, the structure comprising the IC mounting board, the relay board and the mounting board according to claim 7 is the same as the structure described above, wherein the relay board according to any one of claims 1 to 4 is mounted on the IC mounting board and the mounting board. A structure comprising an IC mounting substrate, a relay substrate, and a mounting substrate, wherein the structure is formed by being interposed between the mounting substrate and the mounting substrate.

The structure of the present invention having the above structure is an IC
Since the uneven thermal expansion coefficient of the mounting board is canceled by the interposition of the relay board, a highly reliable structure free from breakage due to the influence of the IC chip is obtained.

[0038]

(Embodiment 1) Next, an embodiment of the invention will be described with reference to the drawings. FIG. 1 is a plan view of a relay board 10 according to the present embodiment, and FIG. 3 is a partially enlarged cross-sectional view of the relay board 10. FIG. 2 is a sectional view of a structure 50 in which the relay board 10 is connected and connected between the IC mounting board 20 and the printed board 30 shown in FIG. As shown in FIG. 1, the relay board 10 has a substantially square flat board-shaped relay board body 1. The relay board main body (hereinafter also simply referred to as the main body) 1 is mainly made of a glass-epoxy resin composite material in which an epoxy resin is impregnated into glass fibers.

However, as shown in FIG. 2, a substantially central portion of the relay board main body 1 is a portion corresponding to the integrated circuit chip (hereinafter, also referred to as an IC chip) 11, that is, the IC mounting board 20.
When connected to (see FIG. 4 (a)), it is a portion 1i where the IC chip 11 is located above (hereinafter, also referred to as an IC chip corresponding portion) 1i. In addition, the thermal expansion coefficient is different between this portion and a portion that surrounds the periphery thereof in a square shape and does not correspond to the IC chip 11 (hereinafter, also referred to as a non-IC chip corresponding portion) 1n. That is, the IC chip corresponding portion 1i of the relay substrate body 1 has a relatively low content of glass fiber, and therefore has a relatively large coefficient of thermal expansion. On the other hand, the IC chip non-compliant portion 1n is
Conversely, the glass fiber content is high, and therefore, the coefficient of thermal expansion in this portion is reduced. Since the coefficient of thermal expansion of glass fiber (α = about 5.6 ppm) is smaller than the coefficient of thermal expansion of epoxy resin (α = 80 to 90 ppm), when both are combined, the more glass fiber contained, ,
This is because the coefficient of thermal expansion becomes smaller. That is, in the relay board of the present embodiment, the thermal expansion coefficient of the relay board main body 1 is smaller in the peripheral portion (the IC chip non-corresponding portion 1n) than in the central portion (the IC chip corresponding portion 1i). Further, the coefficient of thermal expansion of the IC chip corresponding portion 1n is smaller than the coefficient of thermal expansion of the IC mounting substrate main body 21 described later, and therefore, is smaller than the coefficient of thermal expansion of the IC mounting portion 21n.

As shown in FIG. 3, the relay board main body 1
It has a plurality of through holes H penetrating between the first and second surfaces 1a and 1b. The through holes H are perforated in a lattice pattern at a predetermined pitch, and are arranged on almost the entire surface of the relay board main body 1 as shown in FIG. Further, a Cu plating layer 2 (having a thickness of about 15 μm) formed by plating is formed on the inner periphery of the through hole H and the edge of the through hole of the relay substrate body 1.
m) and a metal layer 4 composed of a Ni-B plating layer 3 (about 5 μm thick) formed thereon.
The soft metal body 5 is welded to the B plating layer 3 (metal layer 4). As can be seen from FIG. 3, there is a difference in the material of the relay substrate body 1 between the IC chip corresponding portion 1i (the right half in the drawing) and the non-IC chip corresponding portion 1n (the left half in the drawing) (glass fiber). ), There is no difference in the metal layer 4, the soft metal body 5, the first and second surface side terminals 6, 7, and the like.

This soft metal body 5 is made of Pb-Sn eutectic solder (Pb 36% -Sn 64%), is inserted and fixed in the through hole H, and further, the first surface 1a of the main body 1 (the upper surface in the figure). And a hemispherical first surface side terminal 6 protruding upward in the figure beyond the first surface, and a hemispherical second surface side terminal 7 protruding downward in the figure beyond the second surface 1b.

Next, the relay board 10 is connected to an IC mounting board and a mounting board as follows, for example.
First, as an IC mounting board connected to the relay board 10, an LGA type IC mounting board 20 as shown in FIG. 4A was prepared. The LGA type IC mounting board 20 has an IC mounting board main body 21 having substantially the same planar dimensions as the relay substrate main body 1 and having a substantially square shape in plan view. The IC mounting board main body 21 is mainly made of the same epoxy resin and glass fiber composite material as the relay board main body 1 as an insulating material, and an internal wiring mainly made of Cu (not shown) is formed therein. . On the back surface (lower surface in the figure) 21b (lower surface in the figure) 21b of this IC mounting substrate body 1, in order to connect to a mounting substrate described later, and therefore to connect to the first surface side terminal 6 of the relay substrate 10,
A connection pad 22 made of Cu is formed. The connection pads 22 are also formed in a grid pattern at the same pitch as the through holes H of the relay board main body 1 so as to extend substantially over the entire lower surface 21b.

On the main surface (upper surface in the figure) 21a of the IC mounting substrate main body 21, flip chip pads 23 made of Cu are formed at a predetermined pitch in a vertical and horizontal lattice form over a square area. The IC chip 11 is mounted on the flip chip pad 23 via the solder bump 13 by flip chip connection. The mounted IC chip 11 is made of silicon and has a square plate shape. The IC chip 11 is formed between the IC connection pad 12 formed on the lower surface 11 b of the IC chip 11 and the flip chip pad 23.
They are connected by solder bumps 13 made of Pb-Sn eutectic solder (Pb 36% -Sn 64%). In addition,
In order to strengthen the connection between the IC chip 11 and the IC mounting substrate main body 21 and prevent the solder bumps 13 from breaking, or to protect the integrated circuit formed on the IC chip lower surface 11b side, a broken line in FIG. As shown by, an underfill F for injecting epoxy resin may be provided between the IC chip 11 and the IC mounting substrate body 21.

Further, as shown in FIG.
For convenience, the mounting substrate body 21 is mounted on an IC mounting portion 21i.
And the IC non-mounting portion 21n. IC mounting part 21
i is I on the main surface 21a side of the IC mounting board main body 21.
On the other hand, the IC non-mounting portion 21n is a portion on which the main surface 2 of the IC mounting substrate main body 21 is mounted.
1a indicates a portion where the IC chip 11 is not mounted. Therefore, in the present embodiment, as shown in FIG.
The center of the IC mounting substrate body 21 is the IC mounting portion 21i.
The peripheral portion corresponds to the IC non-mounting portion 21n.

Further, a printed board 30 as shown in FIG. 4B was prepared as a mounting board connected to the relay board 10. The printed circuit board 30 has a substantially square plate shape, includes a printed circuit board main body 31 made of a glass-epoxy resin composite material (JIS: FR-4), and is further provided on a main surface (upper surface) 31 a of the printed circuit board main body 31. Includes a mounting pad 32 formed at a position corresponding to the connection pad 22 of the IC mounting board 20 and, accordingly, the second surface side terminal 7 of the relay board 10. The attachment pad 32 is made of Cu (copper) and is formed at a predetermined pitch so as to correspond to the second surface side terminal 7.

Next, the relay board 10 is connected to the IC mounting board 20, for example, as follows. First, FIG.
As shown in (a), a low-melting-point solder paste (solder composition: Sn 48% -In 52%) P having a melting point of 117 ° C. is applied on the connection pads 22 of the IC mounting board 20 in advance. Then, the IC mounting board 20 is set. At this time, each connection pad 22 is located on the first surface side terminal 6. After that, the IC mounting substrate 2
The IC mounting board 20 is placed on the relay board 10 by lowering 0 and abutting the front end (upper end) of the first surface side terminal 6 so as to be aligned with the connection pad 22. Then, by passing them through a reflow furnace having a maximum temperature of 150 ° C. and heating, the low-melting solder paste P on the connection pads 22 is melted to form a first solder layer 24, as shown in FIG. 5 (b). , IC mounting board 20 and relay board 10
Is connected by soldering to form a connection body 40.
Note that the soft metal body 5 (first and second side terminals 6, 7) and the solder bumps 13 made of Pb-Sn eutectic solder do not melt by the above heating.

As a result, as shown in FIG.
The IC mounting portion 21i of the mounting substrate main body 21 and the IC chip corresponding portion 1i of the relay substrate main body 1 are connected so as to correspond to each other. Further, the IC non-mounting portion 21n of the IC mounting substrate main body 21 and the IC chip non-corresponding portion 1n of the relay substrate main body 1 are connected so as to correspond to each other.

Next, the connection body 40 is connected to the printed circuit board 30 as follows, for example. As shown in FIG. 6, a low melting point solder paste having a melting point of 117 ° C. (solder composition: Sn 48% -In 52
%) P is applied, and the connection body 40 is set on the printed circuit board 30. At this time, each second surface side terminal 7 is positioned on the mounting pad 32. Thereafter, the connecting body 40 is lowered, and the front end (lower end) of the second surface side terminal 7 is abutted so as to be aligned with the mounting pad 32, and the connecting body 40 is mounted on the printed circuit board 30. Next, these are passed through a reflow furnace having a maximum temperature of 150 ° C. and heated to melt the low-melting-point solder paste P on the mounting pad 32 to form the second solder layer 33. As a result, as shown in FIG. 2, the connection body 40 and the printed circuit board 30, and therefore, the IC mounting board 20 and the relay board 10
And the printed circuit board 30 were connected by soldering to complete the structure 50.

Here, the case where the structure 50 in the present embodiment is heated or cooled will be considered. Then, in the IC mounting board 20 of the present embodiment, the IC chip 11 is mounted on the main surface 21a, and the IC mounting board main body 2
1 is mainly composed of a composite material of epoxy resin and glass fiber having relatively small rigidity. Therefore, conventionally, the IC mounting substrate main body 21 is warped in a region where the IC chip 11 having a small coefficient of thermal expansion is mounted. Attempt to deform (see FIG. 24 (a)). For this reason, in the case of the related art in which the solder ball is directly connected to the printed circuit board without using the relay board, as shown in FIG. 24B, the solder ball at the chip-corresponding position may be selectively broken. there were.

However, in this embodiment, FIG.
As shown in (b), the IC mounting portion 21i of the IC mounting substrate main body 21 and the IC chip corresponding portion 1i of the relay substrate main body 1
Are connected correspondingly. Here, the IC chip 11 made of silicon having a low coefficient of thermal expansion is mounted on the main surface 21a side of the IC mounting portion 21i.
Restrained by the IC chip 11, the coefficient of thermal expansion is relatively reduced as compared to the IC non-mounted portion 21n. In contrast,
The portion 1i corresponding to the IC chip has a relatively large glass fiber content, and thus has a large coefficient of thermal expansion. Therefore, both (the IC mounting portion 21i and the IC chip corresponding portion 1i)
Are connected to each other, and when they are viewed as a whole, they have an intermediate coefficient of thermal expansion between them.

Further, the IC non-mounting portion 21n of the IC mounting substrate main body 21 and the IC chip non-corresponding portion 1n of the relay substrate main body 1 are connected so as to correspond to each other. Here, the IC non-mounting portion 21n has an IC chip 11 on its main surface 21a side.
Is not mounted, the thermal expansion is not restricted by the IC chip 11, and therefore, the thermal expansion coefficient is relatively large as compared with the IC mounting portion 21i. On the other hand, since the non-IC chip corresponding portion 1n has a relatively high glass fiber content, the coefficient of thermal expansion is smaller than that of the IC chip corresponding portion. In addition, the thermal expansion coefficient of the non-IC-mounted portion 21n of the IC mounting substrate main body 21 is smaller than the thermal expansion coefficient. Therefore,
By connecting these two parts (the IC non-mounting part 21n and the IC chip non-corresponding part 1n), they are mutually restrained, and when both are viewed as a whole, the coefficient of thermal expansion is intermediate between the two.

That is, regarding the IC mounting board main body 21, the connection of the relay board 10 causes the IC mounting portion 21i to be affected by the IC chip corresponding portion 1i.
The coefficient of thermal expansion is increased. Conversely, the IC non-mounting portion 21n
Is affected by the IC chip non-corresponding portion 1n, and the coefficient of thermal expansion is reduced. That is, connecting the relay board 10 works to reduce a partial difference in the coefficient of thermal expansion of the IC mounting board main body 21. Further, regarding the relay board main body 1, the connection with the IC mounting board 20 causes
The C-chip corresponding portion 1i is affected by the IC mounting portion 21i and has a small coefficient of thermal expansion. Conversely, the IC chip non-corresponding portion 1n is affected by the IC non-mounting portion 21n and has a large coefficient of thermal expansion. That is, the IC mounting substrate 20
Is connected so as to reduce a partial difference in the coefficient of thermal expansion of the relay board main body 1. Therefore, regarding the connection body 40 between the IC mounting board 20 and the relay board 10,
Since the partial difference in the coefficient of thermal expansion is eliminated or reduced, the warpage deformation of the entire connection body 40 is eliminated or reduced. Therefore, in the structure 50 in which the printed circuit board 30 and the connection body 40 are connected, high connection reliability can be obtained without causing breakage unlike the related art.

In order to strengthen the connection between the IC mounting substrate main body 21 and the relay substrate main body 1 and prevent breakage at the first surface side terminal 6 or the first solder layer 24, FIGS.
(b) As shown by broken lines in FIG. 6, between the IC mounting board 20 and the relay board 10, that is, the IC mounting board main body 21.
It is preferable to inject and fill an insulating epoxy resin between the substrate and the relay board main body 1 to form a filling resin layer F2.
By doing so, the IC mounting portion 21i and the IC chip corresponding portion 1i are more strongly bound by the filling resin layer F2, and the IC non-mounting portion 21n and the IC chip non-corresponding portion 1n are similarly They are more strongly bound by F2. Also, the first surface side terminal 6 and the first solder layer 24
Can be dispersed in the filling resin layer F2.

In the first embodiment, the relay substrate 10 is once connected to the LGA type IC mounting substrate 20 to connect the IC mounting substrate to the relay substrate (substrate with relay substrate).
Although an example is shown in which the structure 50 is further connected to the printed circuit board 30 after the formation of the structure 40, a method of manufacturing the structure 50 at once can be adopted. That is, the low-melting solder paste P is applied to the mounting pad 32 and the connection pad 22 in advance,
The printed board 30, the relay board 10, and the LGA type IC mounting board 20 are stacked in this order, reflowed, and the board 20 and the relay board 10, and the relay board 10 and the printed board 40 are connected (soldered) at once. Is also good. Further, the relay board 10 and the printed board 30 may be connected first.

Next, a method of manufacturing the relay board 10 will be described. First, a double-sided copper-clad insulating plate is formed by the following procedure. That is, as shown in FIG. 7A, a non-woven fabric GS made of glass fiber is prepared, and a part of the non-woven fabric GS is made of a non-woven fabric GS ′ from which the glass fiber at the center corresponding to the IC chip corresponding portion 1i is removed later. Specifically, the nonwoven fabrics GS and GS 'are punched and removed by a press, and the nonwoven fabrics GS and GS' are alternately stacked.
Thereafter, an uncured epoxy resin in a fluidized state is applied and impregnated, and is sandwiched by copper foils FL from both sides and vacuum hot pressed. As a result, as shown in FIG. 7 (b), the central portion has a small amount of glass fiber and the peripheral portion has a large amount of glass fiber.
The double-sided copper-clad insulating plate G0 using the epoxy resin composite material as the insulating material G is formed. As shown in FIG. 7 (a), the reason why the non-woven fabric GS 'punched at the center and the non-woven fabric GS not punched were alternately overlapped is to make the distribution of the glass fibers at the center as uniform as possible. . Also, in FIG. 7, the amount of glass fiber is schematically illustrated,
In other drawings, they are omitted. Further, since the subsequent steps are performed by the same method for the central portion (portion corresponding to the IC chip) and the peripheral portion (portion not corresponding to the IC chip), description will be made without particular distinction.

Next, through holes H are formed in the double-sided copper-clad insulating plate G0 at a predetermined pitch by a drill (FIG. 8).
(a)). Then, electroless Cu plating and electrolytic Cu
Plating (15 μm thickness)
The plating layer FL2 is formed (see FIG. 8B). further,
A dry film serving as an etching resist is adhered so as to cover the through hole H, and is exposed and developed to dry films DR1 and DR so as to slightly cover the peripheral edge of the end of the through hole H.
2 (see FIG. 8 (c)).

Then, unnecessary copper (copper foil FL) is removed by etching, the dry films DR1 and DR2 are peeled off, and a copper plating layer 2 is formed in the through hole H and on the periphery of the through hole. An Ni—B plating layer 3 is formed by electroless plating to form a metal layer 4 and cut into a predetermined shape (see FIG. 8D). As a result, the metal layer 4 was formed in the through hole H formed in the relay board main body 1 (1i or 1n) made of the glass-epoxy resin composite material.
The Ni-B plating layer 3 plays a role in preventing the copper plating layer 2 from being eroded by eutectic solder (soft metal body) described later.

Next, the soft metal member 5 is inserted into the through hole H and fixed to the metal layer 4. In the present embodiment, the soft metal body 5 is formed using a solder ball. That is, as shown in FIG. 9, the Pb-Sn eutectic solder ball D is placed on the metal layer 4, that is, on the end of the through hole H on the first surface 1a side. In addition,
To place the ball D on the relay board main body 1, the main body 1
Is set so that the through hole RH of the ball regulating plate R is located above the ball, and the ball D is scattered on the regulating plate R and rocked,
According to the method of dropping the ball D into the through hole RH, the ball D can be easily placed.

Thereafter, under nitrogen atmosphere, the maximum temperature 22
These are charged into a reflow furnace at 0 ° C. and a maximum temperature holding time of 1 minute to melt the eutectic solder balls D. The molten eutectic solder spreads by wetting on the metal layer 4 and filling the through holes H. On the first surface 1a and the second surface 1b, both are made hemispherical by surface tension and cooled to solidify. By doing so, the first surface side terminal 6 and the second surface side terminal 7 are obtained (see FIG. 3). Thereby, as shown in FIGS. 1 and 3, on the first surface 1 a (upper side in the figure) of the relay board main body 1,
A Pb− having a substantially hemispherical first surface side terminal 6 and a substantially hemispherical second surface side terminal 7 on the second surface 1b side.
A soft metal body 5 made of Sn eutectic solder is formed. In addition, the relay board 10 in which such a soft metal body 5 is inserted into and fixed to the through hole H is completed. Since the volume of the eutectic solder ball D is regulated to be constant, the soft metal body 5, the first surface side terminal 6, and the second surface side terminal 7 have a constant amount (volume) and a uniform height. Can be.

Next, a method of manufacturing the IC mounting board 20 will be described. The IC chip 11 shown in FIG. 10A has an integrated circuit formed on a silicon wafer by a well-known integrated circuit forming technique, and is further subjected to vapor deposition and heating on an IC connection pad 12 formed on a surface serving as a chip lower surface 11b. To form solder bumps 13 of Pb-Sn eutectic solder,
It is formed by dicing. Further, as shown in FIG. 10B, a Cu-wiring is formed by plating or etching using a glass-epoxy resin composite material, an epoxy resin and a glass non-woven fabric as an insulating layer by a well-known resin wiring board manufacturing technique. And the LGA type IC mounting substrate body 21
To form Main surface (upper surface) of this IC mounting substrate body 21
Flip chip pads 23 for connecting to the solder bumps 13 of the IC chip 11 are formed on 21a, and connection pads 22 for connecting to the relay board 10 are formed on the back surface (lower surface) 21b.

The IC chip 11 and the IC mounting board main body 2
1 and each solder bump 13 as shown in FIG.
Are positioned so as to correspond to the flip chip pads 23 and are overlaid. Then, both are heated to form the solder bumps 13.
Is melted and welded to the flip chip pad 23, and I
The C chip 11 is mounted on the IC mounting substrate main body 21 (FIG. 4).
(a)). Note that an underfill F for injecting an epoxy resin between the IC chip 11 and the IC mounting substrate main body 21 may be provided as shown by a broken line in FIG.

Further, a method of manufacturing the printed circuit board 30 will be described. As shown in FIG. 11A, a glass-epoxy resin composite material (JIS: FR)
-4) on one side (upper surface in the figure) of the insulating material J, a copper foil F
A single-sided copper-clad insulating plate J0 to which L4 is attached is used. A dry film serving as an etching resist is attached on the copper foil FL4 of the insulating plate J0, and is exposed to a predetermined pattern.
After the development, the dry film DR3 is left in a portion where the mounting pad is to be formed (see FIG. 11B). Next, the exposed copper foil FL4 is removed by etching, the dry film DR3 is peeled off, and cut into a predetermined shape, thereby obtaining the structure shown in FIG.
The main surface 31 of the printed circuit board main body 31 as shown in FIG.
The printed board 30 in which the mounting pads 32 are formed on a is completed.

(Embodiment 2) Next, a second embodiment will be described. In this embodiment, among the soft metal bodies formed on the relay board main body, the shape of the second surface side terminal and the manufacturing thereof are described. Since only the steps are different, similar parts are omitted, and only different parts will be described. FIG. 12 shows a second embodiment.
Is a partially enlarged cross-sectional view of the relay board 10B according to FIG. This relay board 10B is made of glass, similar to the first embodiment.
The relay board main body 1 is made of an epoxy resin composite material, and has a glass fiber content greater in the IC chip non-corresponding portion 1n than in the IC chip corresponding portion 1i. Further, a through hole H and a metal layer 4 are formed in the main body 1 as in the first embodiment.

The through hole H (metal layer 4) has P
A soft metal body 5B made of b-Sn eutectic solder is inserted and fixed, and the first surface side constitutes the first surface side terminal 6B and the second surface side constitutes the second surface side terminal 7B. . The first surface side terminal 6B is similar to the first surface side terminal 6 of the first embodiment.
It is hemispherical. On the other hand, the second surface side terminal 7B has a substantially constant diameter CBD (hence the maximum diameter ABD = CB) in the height direction (axial direction, vertical direction in the drawing) except for the tip end.
D), the tip (the lower end in the figure) is hemispherical, and the height CBH from the second surface 1b is larger than the maximum diameter ABD.

This relay board 10B is similar to the relay board 10 shown in the first embodiment (FIGS. 2, 5, and 6).
Also, when the structure 50B (not shown) is formed by connecting to the IC mounting board 20 and the printed board 30, the difference in the coefficient of thermal expansion between the IC chip 11 and the IC mounting board main body 21 causes the IC mounting board to be different. The main body 21 is going to warp and deform. However, as described in the first embodiment, the IC mounting portion 21i of the IC mounting substrate main body 21 and the IC chip corresponding portions 1i of the relay substrate main body 1 and I
The IC non-mounting portion 21n of the C mounting substrate main body 21 and the IC chip non-corresponding portion 1n of the relay substrate main body 1 mutually restrain thermal expansion. Therefore, regarding the connection body 40B (not shown) between the IC mounting board 20 and the relay board 10B, since the partial difference in the coefficient of thermal expansion is eliminated or reduced, the warpage deformation of the connection body 40B as a whole is reduced. Eliminate or reduce. That is, the relay board 10B
When the IC mounting board 20 and the printed circuit board 30 are connected via the interface, high connection reliability can be obtained.

Further, in the relay board 10B of the present embodiment, the second surface side terminal 7B is made of a soft metal (Pb-Sn eutectic solder) and has a substantially columnar shape having a height CBH higher than its maximum diameter ABD. ing. For this reason, even if the warping deformation remains in the connection body 40B, as shown in FIG. 13A, the second surface side terminal 7B of the relay board 10B is moved in the height direction (the thickness direction of the relay board: Direction) (elongation in this drawing) and release the stress following the warping deformation, so that it does not break.

Further, when the structure 50B is heated or cooled, deformation occurs in the direction (lateral direction in the drawing) along the second surface 1b due to the difference in thermal expansion between the relay board main body 1 and the printed board main body 31. There is. This is because the relay board main body 1 and the printed board main body 31 are substantially the same material (glass-epoxy resin composite material), but are not completely the same. When such a thermal expansion difference occurs, the relay board main body 1 and the printed circuit board main body 31 tend to be displaced in the directions opposite to each other in the direction along the second surface 1b.
Also in that case, since the substantially columnar second surface side terminal 7B is formed in the relay board 10B according to the present embodiment,
For example, as shown in FIG.
Even if 1 is displaced to the left in the drawing, the second surface side terminal 7B is bent and deformed to absorb the stress as shown by the solid line, so that it does not break. As described above, in the present embodiment, since the second surface side terminal 7B is made of a soft metal and has a substantially columnar shape, stress is released by expansion and contraction deformation and bending deformation, so that higher connection reliability is obtained. be able to.

In order to form such a soft metal body 5B (second surface side terminal 7B), it can be formed by the following method using, for example, a columnar terminal forming jig N and a load jig M.
That is, as shown in FIG. 14 (a), the upper surface N3 of the columnar terminal forming jig N made of carbon has a predetermined diameter and depth at positions corresponding to the through holes H of the relay board main body 1, respectively. A concave portion N1 having a conical tip is formed. Also,
A small-diameter gas vent hole N2 penetrating the columnar terminal forming jig N downward is formed at the top (the lowermost portion in the figure) of the concave portion N1 of the columnar terminal forming jig N. Note that carbon (graphite) is a material that has heat resistance and does not wet the molten Pb-Sn eutectic solder.

First, each concave portion N of this columnar terminal forming jig N
First, a Pb—Sn eutectic solder (Pb
(36% -Sn64%) The ball D1 is thrown in. In this example, two pieces were put into each recess. Next, the concave portion N
1 at the end (upper end), a Pb-Sn having a diameter larger than this diameter.
The eutectic solder ball D2 is placed. At this time, the concave portion N1
It is preferable that the distance between the balls D1 and D2, which have already been charged, be kept small so that they do not come into contact with each other and come into contact with each other when the eutectic solder described later is melted. In this case, the ball D2 comes into close contact with the upper end edge of the concave portion N1 and does not move (or hardly moves), so that the positioning when the relay board main body 1 described later is mounted becomes easy.

Thereafter, as shown in FIG. 14 (b), the relay board main body 1 is placed above the ball D2 with the second surface 1b facing down. At this time, the positioning is performed so that the ball D2 fits into the through hole H. Further, the load jig M is placed on the second surface 1b (upper side in the figure) of the relay board main body 1. The load jig M is also made of carbon, and a hemispherical concave portion M1 is formed on the lower surface M2 at a position corresponding to the through hole H.

Next, the maximum temperature 210
These are put into a reflow furnace at a holding temperature of 183 ° C. or more for 2 minutes to melt the eutectic solder balls D1 and D2.
Then, the molten eutectic solder D2 is pushed down in the figure by the weight of the load jig M and the relay substrate main body 1, and
It is inserted into the through hole H of the main body 1 and is welded to the metal layer 4 on the inner periphery of the through hole H. On the other hand, at the upper end of the through hole H, the eutectic solder D2 exceeds the first surface 1a (the upper surface in the figure),
It bulges in a hemispherical shape following the concave portion M1. The eutectic solder D2 is also injected into the concave portion N1 of the columnar terminal forming jig N. Then, it comes into contact with the molten eutectic solder D1, and both tend to be united by surface tension. However, since the eutectic solder D2 is welded to the metal layer 4 and is integrated with the main body 1, the eutectic solder D2 cannot separate from the main body 1 and fall down. Integrate by pulling up. The main body 1 is pushed down by the load jig M to a state close to the upper surface N3 of the columnar terminal forming jig N.

The gas vent hole N2 plays a role of releasing air trapped in the concave portion N1 when melting the eutectic solder balls D1 and D2. However, since the pillar-shaped terminal forming jig N does not wet the solder and the gas vent hole N2 has a small diameter, the solder does not enter the gas vent hole N2.

Then, the eutectic solder is solidified by cooling. As a result, as shown in FIG.
On the second surface 1b side (lower side in the figure), the side surface follows the shape of the side wall of the concave portion N1, and the distal end portion has a substantially hemispherical second surface side terminal 7B, and the first surface 1a side ( The concave M
A soft metal body 5B made of Pb-Sn eutectic solder having a first surface side terminal 6B which is substantially hemispherical in accordance with 1 is formed. Further, the relay board 10B in which such a soft metal body 5B is inserted and fixed in the through hole H is completed.

(Embodiment 3) Next, a third embodiment will be described. This embodiment includes a substantially columnar second surface side terminal, as in the second embodiment. However, Embodiments 1 and 2
Unlike the relay board main body, a portion not corresponding to the IC chip is provided with a low thermal expansion plate in order to reduce the thermal expansion coefficient of this portion. Further, the first surface side terminal is formed of solder having a lower melting point than the soft metal body inserted into the through hole. Referring to the partially enlarged cross-sectional view of FIG.
The relay substrate 10C according to the present embodiment has a relay substrate main body 1C including an IC chip corresponding portion 1Ci having a relatively large coefficient of thermal expansion and an IC chip non-corresponding portion 1Cn having a relatively small coefficient of thermal expansion. Embodiment 1 and Embodiment 1
2, a through hole H is formed.
The inner periphery and the end periphery of are similar to the first and second embodiments,
A metal layer 4 including a Cu plating layer 2 and a Ni—B plating layer 3 is formed.

A soft metal body 5C made of Pb-Sn eutectic solder is inserted into and fixed to the through hole H. The first surface 1Ca side is substantially flush with the first surface 1Ca. On the other hand, the second surface 1Cb side constitutes a second surface side terminal 7C. The second surface side terminal 7C has a substantially constant diameter CCD (hence the maximum diameter ACD = CC) in the height direction (axial direction, vertical direction in the figure) except for the tip end.
D), the tip (the lower end in the figure) is hemispherical, and the height CCH from the second surface 1Cb is larger than the maximum diameter ACD. Further, on the first surface 1Ca side of the soft metal body 5C, Sn48% -In
A first surface side terminal 6C made of 52% low melting point solder and raised substantially in a hemispherical shape is formed.

The portion 1Ci corresponding to the IC chip in the relay board main body 1C is made of a glass-epoxy resin composite material (α = 15 to 20 ppm) in which glass fiber is impregnated with epoxy resin.
(Degree: planar direction). On the other hand, the IC chip non-corresponding portion 1Cn is also made of a glass-epoxy resin composite material, but has a lower coefficient of thermal expansion than this, specifically, an aluminum nitride (AlN) ceramic plate 8
(Α = 4.5 ppm). In the present embodiment, the ceramic plate 8 is positioned substantially at the center in the thickness direction, and both surfaces of the ceramic plate 8 are sandwiched between insulating layers made of a glass-epoxy resin composite material. Therefore, I
The coefficient of thermal expansion of the non-C chip corresponding portion 1Cn is reduced by the influence of the ceramic plate 8.

Using such a relay board 10C, an IC
The connection with the mounting board 20 and the printed board 30 is the same as that described in the first embodiment. That is, the IC mounting portion 21i of the IC mounting substrate main body 21 and the IC chip corresponding portion 1Ci of the relay substrate main body 1C, and I
The IC non-mounting portion 21n of the C mounting substrate main body 21 and the IC chip non-corresponding portion 1Cn of the relay substrate main body 1C restrain thermal expansion with each other. Therefore, regarding the connection body 40C (not shown) between the IC mounting board 20 and the relay board 10C, the partial difference in the coefficient of thermal expansion is eliminated or reduced, so that the warpage deformation of the connection body 40C as a whole is reduced. Eliminate or reduce. That is, this relay board 1
If the IC mounting board 20 and the printed board 30 are connected via the OC, high connection reliability can be obtained.

Further, in the relay board 10C of the present embodiment, the second surface side terminal 7C has a substantially columnar shape having a height CCH higher than its maximum diameter ACD, as in the second embodiment. For this reason, even if the warpage deformation remains in the connection body 40C, the second surface side terminals 7C of the relay board 10C expand and contract in the height direction (thickness direction of the relay board), and release the stress following the warp deformation. Therefore, it does not break (see FIG. 13A). Also, when the relay board body 1C and the printed board body 31 are displaced relatively in opposite directions in the direction along the second surface 1Cb due to the difference in thermal expansion between the relay board body 1C and the printed board body 31, the same as in the second embodiment. In addition, since the substantially columnar second surface side terminal 7C bends and deforms to absorb the stress, it does not break (see FIG. 13B). Therefore, the second surface side terminal 7C is made of a soft metal,
In addition, the connection reliability can be further improved due to the substantially columnar shape.

Further, in the present embodiment, the first
The surface side terminal 6C has a lower melting point solder (Sn 48% -In 52%) than the soft metal body 5C (Pb-Sn eutectic solder).
Consists of Therefore, the IC mounting board 20 and the relay board 10C
As described in the first embodiment, it is not necessary to apply the low-melting solder paste P to the connection pads 22 in advance (see FIG. 5A).
If C and IC mounting substrate 20 are overlaid and heated, both can be connected.

Next, a method of manufacturing the relay board 10C according to the present embodiment will be described, focusing on the differences from the first or second embodiment. First, as shown in FIG.
A ceramic plate 8 made of N ceramic is prepared. This ceramic plate 8 has an IC chip corresponding portion 1C at its center.
A rectangular opening 8op having a size corresponding to i is formed to have a substantially rectangular shape, and further, through holes 8h are formed in a lattice shape. Next, as shown in FIG. 16 (b), the prepreg P was placed in a semi-cured state by impregnating glass fiber with epoxy resin from above and below, as shown in FIG.
P and the copper foil FL. It is preferable that the prepreg PP ′ cut into a size that just fits into the opening 8op is put into the opening 8op. This is because the glass fibers are contained in the opening 8op to the same extent as the other parts. This is further hot-pressed in a vacuum to melt the prepregs PP and PP ', to flow the epoxy resin into the through holes 8h, and to further cure the epoxy resin. Then, as shown in FIG. 16C, the central portion (the portion that becomes the IC chip corresponding portion 1Ci) does not have the ceramic plate 8,
A double-sided copper-clad insulating plate G3 having an insulating layer G made of a glass-epoxy resin composite material with a ceramic plate 8 interposed therebetween is provided in a peripheral portion (a portion to be an IC chip non-corresponding portion 1Cn).
Is formed.

Next, the through holes H are formed in a grid pattern at a predetermined pitch as in the first embodiment (see FIG. 8A). However, as shown in FIG. 16 (d), the through hole H is positioned and drilled so that the through hole H is positioned within the through hole 8h in the peripheral portion. Thereafter, the metal layer 4 is formed in the through hole H in the same manner as in the first embodiment (see FIG. 8).

In order to insert and fix the soft metal body 5C having the substantially columnar second surface side terminal 7B into the through hole H, the columnar terminal forming jig N used in the second embodiment may be used. However, in order to flatten the soft metal body 5C without rising on the first surface 1Ca side, the lower surface Q2 is made flat instead of the load jig M having the hemispherical concave portion M1 used in the second embodiment. A carbon load jig Q is used (see FIG. 17B). As in the second embodiment, the eutectic solder ball D1 is put into the concave portion N1, and the eutectic solder ball D2 is placed on the end of the concave portion N1 (see FIG. 17A). Then, the relay board main body 1C is placed, and the lower surface Q2 is heated while being pressed by the flattened load jig Q to melt the eutectic solder balls D1, D2.
Thereby, on the second surface (lower surface in the figure) 1Cb side of the main body 1C, a soft metal having a second surface side terminal 7C whose side surface follows the shape of the side wall of the concave portion N1 and whose tip portion is substantially hemispherical. Body 5
C is inserted and fixed in the through hole H. On the other hand, the first surface 1Ca side (upper side in the figure) of the soft metal body 5C follows the lower surface Q2 of the load jig Q, and is substantially flush with the first surface 1Ca.
a.

Further, as shown in FIG. 18, the first surface 1C of the soft metal body 5C is formed to form the first surface side terminal 6C.
A low melting point solder ball E (Sn 48%-
In 52%). In order to place the ball E, the ball E is set so that the through hole RCH of the ball regulating plate RC is located above the soft metal body 5C, and the ball E is scattered and rocked on the regulating plate RC. According to the method of dropping the ball E into the through hole RCH, the ball E can be easily placed. In the present example, as shown in FIG.
A soft metal body holding jig U having a concave portion U1 into which the tip portion 7Ca of C fits is used, and the concave portion U1 of the jig U is used.
It is convenient to perform the process with the tip portions 7Ca fitted in the respective portions. This is because the soft metal body 5C (the column-shaped second surface side terminal 6C) is made of a soft and easily deformable Pb-Sn eutectic solder.

Thereafter, under a nitrogen atmosphere, a maximum temperature of 15
These are charged into a reflow furnace at 0 ° C. and a maximum temperature holding time of 1 minute to melt the low melting point solder balls E. Under this temperature condition, the soft metal body 5C does not melt. The molten low melting point solder spreads wet on the upper surface 5Ca of the soft metal body,
The first surface side terminal 7C is substantially hemispherical, and the relay board 10C is completed (see FIG. 15). Since the low melting point solder ball E whose volume was regulated to be constant was used, the first surface side terminal 7C had a constant amount (volume) and could have a uniform height.

In the third embodiment, the AlN ceramic plate 8 is used as the low thermal expansion plate, but another ceramic may be used. For example, alumina, mullite, silicon nitride, sialon and the like can be mentioned. In particular, among these ceramics, AlN, alumina, mullite, silicon nitride, etc. are all insulating, and even if the position of the through hole H is slightly shifted, the metal layer 4 formed on the inner peripheral surface of the through hole H This is more preferable because there is no short circuit between the and the low thermal expansion plate. On the other hand, as the low thermal expansion plate, a low expansion metal plate may be used. Specifically, 42 alloy (42% Ni-Fe alloy), Kovar, molybdenum, tungsten, CIC (Cu / invar / Cu clad material) And the like. When these low expansion metal plates are used, the through holes 8h can be formed by drilling, punching or the like, which is preferable in that the production becomes easy.

(Embodiment 4) Next, a relay board 70 according to a fourth embodiment will be described. The relay board 70 of the present embodiment is different from the relay boards of the first to third embodiments in that a soft metal body is not inserted into and fixed to a through hole. The IC mounting board 20 and the printed board 30 connected to the relay board 70 are the same as those of the first embodiment.
The description is omitted because it is similar to the above.

FIG. 19 shows a relay board 7 according to this embodiment.
0 shows a partially enlarged sectional view. The relay board 70 includes a main body core board 71A, a first insulating layer 71B, and a second insulating layer 71B.
C, a filling via 78, and a relay board main body 71 composed of wiring layers 79A and 79B. The main body core substrate 71A of the relay substrate main body 71 is made of a glass-epoxy resin composite material, and a through hole H7 formed at a predetermined pitch in the main body core substrate 71A has a conductive material made of a mixture of epoxy resin and copper powder. Filled vias 78 are formed by filling with resin. In addition, the upper surface 71A of the main body core substrate 71A in the drawing.
a and a lower surface 71Ab are provided with a wiring layer 79A made of copper,
79B is formed so as to cover the upper and lower ends of the filling via 78 as well.

Further, the upper surface 71A of the main body core substrate 71A
A first insulating layer 71B made of epoxy resin is formed from above a to the wiring layer 79A while exposing a part of the wiring layer 79A as a first surface side pad 79AO. Similarly, from the lower surface 71Ab of the main body core substrate 71A to the wiring layer 79B, a second insulating layer 71C made of an epoxy resin is formed while a part of the wiring layer 79B is exposed as a second surface pad 79BO. ing.

Further, it is composed of Pb—Sn eutectic solder,
A substantially hemispherical first surface side terminal 76 is welded to the exposed portion 79AO of the wiring layer 79A and protrudes upward in the figure beyond the first surface 71a. A substantially columnar first surface side terminal 77 made of Pb-Sn eutectic solder and having a hemispherical tip and a height higher than the maximum diameter is provided on the exposed portion 79 of the wiring layer 79B.
It is welded to the BO and protrudes downward in the figure beyond the first surface 71b. The first side terminal 76 and the second side terminal 77
Are formed at positions corresponding to each other and at positions corresponding to the connection pads 22 of the IC mounting board 20 and the mounting pads 32 of the printed board 30.

In the main body core board 71A of the relay board main body 71, the content of glass fiber is larger in the peripheral part than in the central part, similarly to the relay substrate main body 1 used in the first embodiment. Accordingly, the thermal expansion coefficient of the peripheral portion of the main body core substrate 71A is lower than that of the central portion, and the thermal expansion coefficient of the non-IC chip corresponding portion 71n is smaller than that of the IC chip corresponding portion 71i of the relay substrate main body 71. . When the relay board 70 having the relay board main body 71 and the IC mounting board 20 are connected, the same as in the first and second embodiments.
That is, the IC mounting portion 21i of the IC mounting substrate main body 21, the IC chip corresponding portion 71i of the relay substrate main body 71, and
The IC non-mounting portion 21n of the IC mounting substrate main body 21 and the IC chip non-corresponding portion 71n of the relay substrate main body 1C mutually restrain thermal expansion. Therefore, the IC mounting substrate 20
With respect to the connector 40D (not shown) between the connector 40D and the relay board 70, the partial difference in the coefficient of thermal expansion is eliminated or reduced, so that the warpage deformation of the entire connector 40D is eliminated or reduced. That is, this relay board 7
When the IC mounting board 20 and the printed circuit board 30 are connected via the “0”, high connection reliability can be obtained.

Further, in the relay board 70 of the present embodiment,
The second surface side terminal 77 has a substantially columnar shape having a height higher than its maximum diameter, as in the second embodiment. For this reason, even if the warping deformation remains in the connection body 40D, the second surface side terminal 77 of the relay board 70 is moved in the height direction (thickness direction of the relay board) similarly to the second surface side terminal 7B in the second embodiment. ), And does not break because the stress is released following the warping deformation (see FIG. 13A). The same as in the second embodiment, when the relay board body 71 and the printed circuit board body 31 are displaced relatively in opposite directions in the direction along the second surface 71b due to the difference in thermal expansion between the two. In addition, since the substantially columnar second surface side terminal 77 is bent and deformed to absorb stress,
Does not break (see FIG. 13 (b)). Therefore, since the second surface side terminal is made of a soft metal and has a substantially columnar shape, the connection reliability can be further improved.

Next, a method of manufacturing the relay board 70 of the present embodiment will be briefly described. Later the main body core board 71
The glass-epoxy resin composite material serving as A is used as an insulating material,
A double-sided copper-clad insulating plate having copper foils attached to both sides is prepared, and a through hole H7 is formed. In addition, this double-sided copper-clad insulation board
By the same process as described in the first embodiment, the content of the glass fiber is increased in the peripheral portion as compared with the central portion (see FIG. 7). Further, a conductive resin made of a mixture of an epoxy resin and a copper powder is filled in the through-hole H7, and is cured by heating to form a filled via 78. Thereafter, electrolytic Cu plating is performed, and a Cu plating layer is deposited on the copper foil adhered to both surfaces of the insulating layer and the upper and lower end surfaces of the filling via 78.
As a result, the copper foil becomes thicker, and a Cu plating layer is formed on the upper and lower end surfaces of the filling via 78. The filling via 7
Since 8 has conductivity, direct electrolytic plating is possible.

Next, a dry film resist is attached, exposed and developed to form a predetermined pattern, unnecessary copper (copper plating layer and copper foil) is removed by etching, and the dry film is also removed. Thereby, the wiring layers 79A, 7A
9B is upper and lower surfaces 71Aa, 71Ab of the main body core substrate 71A.
Could be formed. Furthermore, the upper and lower surfaces 7 of the main body core board 71A
1Aa, 71Ab and the wiring layers 79A, 79B,
A photosensitive solder resist made of an epoxy resin is applied, exposed and developed, and the first surface side pad 79AO and the second
A portion to be the surface-side pad 79BO is exposed, and then heated to cure the solder resist, thereby forming the first and second insulating layers 71B and 71C. Thus, the relay board main body 71 was formed.

Next, the first and second surface side terminals 76 and 77 are formed as follows. As the second surface side terminal 77, the columnar terminal forming jig N used in the second and third embodiments is used. That is, the eutectic solder ball D1 is put into the columnar terminal forming jig N similarly to the second embodiment, and the eutectic solder ball D2 is placed at the end of the concave portion N1 (FIG. 2).
0 (a)), and then place the relay board main body 71 on the first surface 71a (not shown) so that the relay board main body 71 will surely descend in the following process. Or put a weight. On the other hand, although not shown, the first surface side pad 79A
Eutectic solder paste is applied on O.

Then, in a nitrogen atmosphere, a maximum temperature of 210
The eutectic solder balls D1 and D2 and a eutectic solder paste (not shown) are charged into a reflow furnace having a holding time of 2 minutes at a temperature of 183 ° C. or higher. As a result, on the second surface (lower surface in the figure) 71b side of the main body 71, the side surface follows the shape of the side wall of the concave portion N1, and the front end portion becomes substantially hemispherical.
A substantially columnar second surface side terminal 77 is formed. On the other hand, on the first surface 71a side (not shown), the applied eutectic solder paste is melted and welded to the first surface side pad 79AO to form a first surface side terminal 76 which is made substantially hemispherical by surface tension. .
Thereafter, when the eutectic solder is solidified by cooling, the wiring substrate 70 is completed (see FIG. 19).

In the fourth embodiment, the first surface side terminal 76 is formed of eutectic solder. However, the first surface side terminal 76 is formed by applying and melting a low melting point solder paste. For example, it may be constituted by (Sn 48% -In 52%).

In the second to fourth embodiments, as the second surface side terminal, a columnar terminal having the same diameter except for the tip is shown. However, more preferably, the shape of the base end near the second surface of the second surface side terminal is such that the diameter gradually increases from the front end toward the base end. Specifically, for example,
The intermediate portion 87b between the distal end portion 87a and the proximal end portion 87c of the second surface side terminal 87, or the distal end portion 87a and the intermediate portion 8
7b has a slightly smaller diameter, and the base end portion 87c has a skirt shape (FIG. 2).
1 (a)) or meniscus shape (see FIG. 21 (a))
It is good to gradually increase the diameter. In this way, when the substantially columnar second surface side terminal 87 expands and contracts or bends and deforms, the stress applied to the vicinity of the base end portion 87 can be dispersed, and it can be harder to break, thereby further improving connection reliability. This is because it can be done. In order to form the second surface side terminal in this manner, for example, in the columnar terminal forming jig N described above, the concave portion N1 has a slightly smaller diameter, and the upper end N3 side end portion is C-chamfered or R-chamfered. It can be formed by keeping the shape.

In the above, the present invention has been described with reference to the respective embodiments. However, the present invention is not limited to the above-described embodiments, and may be appropriately modified and applied without departing from the scope of the invention. Needless to say.

[Brief description of the drawings]

FIG. 1 is a plan view of a relay board according to a first embodiment.

FIG. 2 is a cross-sectional view of a structure including an IC mounting board, a relay board, and a mounting board according to the first embodiment.

FIG. 3 is a partially enlarged cross-sectional view of the relay board according to the first embodiment.

4A is a cross-sectional view of an IC mounting board connected to a relay board, and FIG. 4B is a cross-sectional view of a mounting board.

FIG. 5A is an explanatory view showing a state in which the relay board and the IC mounting board according to the first embodiment are connected, and FIG. 5B is a cross-sectional view of a connection body connecting the both.

FIG. 6 is an explanatory diagram showing a state in which a connection body is connected to a printed circuit board.

FIG. 7 is an explanatory view showing a process until a double-sided copper-clad insulating plate is formed in the method of manufacturing the relay board according to the first embodiment.

FIG. 8 is an explanatory diagram illustrating a process until a metal layer is formed in the through hole in the method of manufacturing the relay board according to the first embodiment.

FIG. 9 is an explanatory view showing a step of inserting a soft metal body into the through hole in the method of manufacturing the relay board according to the first embodiment.

FIG. 10 is an explanatory diagram illustrating a method for manufacturing an IC mounting substrate.

FIG. 11 is an explanatory diagram illustrating a method for manufacturing a printed circuit board.

FIG. 12 is a partially enlarged cross-sectional view of the relay board according to the second embodiment.

13A and 13B are explanatory views showing a state of deformation of the first surface side terminal when stress is applied, where FIG. 13A is a case where a stress is applied in a height direction, and FIG. 13B is a lateral direction (a radial direction). In this case.

FIG. 14 is an explanatory view showing a step of inserting a soft metal body into a through hole in the method of manufacturing the relay board according to the second embodiment.

FIG. 15 is a partially enlarged cross-sectional view of a relay board according to a third embodiment.

FIG. 16 is an explanatory diagram illustrating steps of forming a double-sided copper-clad insulating plate partially including a low-thermal-expansion plate and forming a through hole in the method of manufacturing the relay board according to the third embodiment.

FIG. 17 is an explanatory diagram illustrating a step of forming a second surface side terminal in the method of manufacturing the relay board according to the third embodiment.

FIG. 18 is an explanatory diagram illustrating a step of forming a first surface side terminal in the method of manufacturing the relay board according to the third embodiment.

FIG. 19 is a partially enlarged cross-sectional view of a relay board according to a fourth embodiment.

FIG. 20 is an explanatory diagram illustrating a step of forming a second surface side terminal in the method of manufacturing a relay board according to the fourth embodiment.

FIGS. 21A and 21B are partial enlarged cross-sectional views showing examples of the shape of the base end of the second surface side terminal, where FIG. 21A shows the base end in a skirt shape and FIG. 21B shows a meniscus shape.

22 (a) is an explanatory view showing a structure of a relay board, and FIG. 22 (b) is a view showing a state in which a relay board is interposed between two boards.

FIG. 23 is an explanatory diagram showing a state in which another conventional relay board is interposed between two boards.

24A and 24B show an integrated circuit chip mounted thereon, in which an IC mounting board having a wiring board body made of a material containing a resin is connected to a printed board, in which FIG. 24A emphasizes deformation when the board is heated. FIG. 4B is a schematic diagram illustrating a location where a connection terminal is broken.

[Explanation of symbols]

10, 10B, 10C, 70 Relay substrate 1, 1B, 1C, 71 Relay substrate main body 1a, 1Ca, 71a First surface 1b, 1Cb, 71b Second surface 1i, 1Ci, 71i IC chip corresponding portion 1n, 1Cn, 71n IC Chip non-corresponding part 2 Cu plating layer 3 Ni-B plating layer 4 Metal layer 5, 5B, 5C Soft metal body 6, 6B, 6C, 76 First surface side terminal 7, 7B, 7C, 77 Second surface side terminal 8 Low thermal expansion plate 8 op opening 11 IC chip 12 IC connection pad 13 solder bump 20 IC mounting board 21 IC mounting board main body 21 i IC mounting portion 21 n IC non-mounting portion 22 connection pad 23 flip chip pad 24 first solder layer 30 printed board (mounting board) 31) Printed circuit board main body 32 Mounting pad 33 Second solder layer 40 Connection body 50 Structure H, H Holes F underfill F2 filled resin layer

Claims (7)

[Claims] 1. An IC mounting substrate main body made of a material including a resin and having a substantially plate shape having a main surface and a back surface, an integrated circuit chip mounted on the main surface side, and at least the integrated circuit out of the back surface side An IC mounting substrate including a connection pad formed at a position corresponding to the chip, a mounting substrate body, and a mounting formed at a position on the main surface of the mounting substrate body corresponding to the connection pad of the IC mounting substrate. And a mounting board provided with the pad, and connected to the connection pad on the first surface side and connected to the mounting pad on the second surface side, thereby connecting the IC mounting board and the mounting board. A relay board for connection, having a substantially plate shape having the first surface and the second surface, a relay substrate body made of a material containing resin, and a first surface formed on the first surface side Side terminal and the second surface side And a second surface side terminal formed at a position corresponding to the first surface side terminal, and electrically connected to the first surface side terminal. A relay board, wherein the thermal expansion coefficients of other parts are smaller than the thermal expansion coefficients of the corresponding parts. 2. The relay board according to claim 1, wherein the relay board body is made of a resin and a fiber having a smaller coefficient of thermal expansion than the resin, and is made of at least one of a glass fiber and an organic fiber. And a main body fiber, wherein the other portion of the relay substrate main body has a higher content of the main body fiber than a portion corresponding to the integrated circuit chip. substrate. 3. The relay board according to claim 1, wherein the other portion of the relay board body has a smaller thermal expansion coefficient than a portion corresponding to the integrated circuit chip. A relay board comprising a low thermal expansion plate having an expansion coefficient. 4. The relay board according to claim 3, wherein the low thermal expansion plate is made of an insulating ceramic. 5. A connection body between an IC mounting board and a relay board, wherein the relay board according to claim 1 and the IC mounting board are connected to each other. 6. A connection body between the IC mounting board and the relay board according to claim 5, wherein an insulating resin for connecting the IC mounting board body and the relay board main body is filled between the IC mounting board body and the relay board body. A connection body between the IC mounting board and the relay board. 7. An IC mounting board, wherein the relay board according to claim 1 is interposed and connected between the IC mounting board and the mounting board. A structure consisting of a relay board and a mounting board.