JP2003203943A - Flip-chip mounting substrate, manufacturing method and radio device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flip-chip mounting substrate, improved in a heat radiating efficiency, while having a structure capable of contriving the reduction of size and weight as a whole while securing a mounting area. <P>SOLUTION: A silicon substrate 11, on the one side main surface of which pole electrodes 112g, 112f and an IC chip 11a are mounted, and a printed substrate 10, arranged so as to be opposed to the main surface, are electrically connected via the pole electrode 112g and the like. A grand pattern 17b is patterned at a position opposed to the IC chip 111a on the printed substrate 10. The IC chip 111a is mounted on the silicon substrate 11 as the flip-chip and is soldered to the grand pattern 17b via a solder layer 18b. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a first circuit board on which a semiconductor element is flip-chip mounted and a flip circuit on which a second circuit board is arranged so as to face a main surface on which the semiconductor element is mounted. The present invention relates to a chip mounting board, a method for manufacturing the flip chip mounting board, and a wireless device including the flip chip mounting board, and more particularly to improvement of heat dissipation characteristics.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for reducing the size and weight of wireless devices such as mobile phones. Therefore, there is an urgent need to reduce the size and weight of circuit boards constituting the wireless devices. Flip-chip mounting technology is being developed to meet such demands. For example, Japanese Patent Application Laid-Open No. 8-255965 discloses a microchip module assembly in which an IC chip is flip-chip mounted. FIG. 9 is a view showing a cross section of a microchip module assembly according to the conventional publication. As shown in FIG. 9, the microchip module assembly 5 is obtained by mounting a silicon substrate 51 on which an IC chip 52 is flip-chip mounted on a printed circuit board 50 via ball electrodes 53a and 53b. The board 51 is arranged so that the surface on which the IC chip 52 is mounted faces the printed board 50.

The height of the ball electrodes 53a and 53b is larger than the height of the IC chip 52, and the IC chip 5
A space is left between 2 and the printed circuit board 50. The silicon substrate 51 and the printed circuit board 50 have ball electrodes 53a,
It is electrically connected via 53b, and a polymer encapsulant 5 is provided in the gap between the silicon substrate 51 and the printed circuit board 50.
4a to 54c are filled and hardened by pouring heat treatment to maintain adhesion strength and ensure reliability against thermal stress.

As described above, according to the technique disclosed in the above publication, the mounting area is secured by using the silicon substrate, and the total thickness of the circuit board including the silicon substrate and the printed circuit board is reduced to reduce the size and weight. Can be realized.

[0005]

However, in a wireless device, the IC chip generates a large amount of heat particularly in the transmitting side circuit, and when the above configuration is applied to the wireless device, a circuit malfunction occurs. Therefore, like a mobile phone,
In the case of a device that is required to have high environment resistance assuming use in various situations, sufficient quality cannot be ensured by the technique of the above publication.

The present invention has been made in view of the above problems, and has a structure in which the mounting area can be secured and the overall size and weight can be reduced, while the heat dissipation efficiency is further improved. Chip mounting board, manufacturing method,
And a wireless device.

[0007]

In order to solve the above-mentioned problems, a flip-chip mounting board according to the present invention comprises a first circuit board on which a semiconductor element is flip-chip mounted,
A flip-chip mounting board comprising a second circuit board arranged so as to face a main surface on which the semiconductor element of the first circuit board is flip-chip mounted, the semiconductor element and the second circuit board. Is connected to the circuit board via a conductive member.

With this arrangement, the mounting area can be secured and the overall size and weight can be reduced, and the heat generated by the semiconductor element can be conducted to the second circuit board to improve the heat dissipation efficiency. . The conductive member is preferably formed by solidifying solder paste or silver paste. Further, the first circuit board and the second circuit board may be separated from each other by a separating member that is larger than the thickness of the semiconductor element. Further, the separating member may include the semiconductor element. In the ball electrode having a diameter larger than the thickness, it is preferable that the first circuit board and the second circuit board are electrically connected by the ball electrode.

The second circuit board is effective in preventing noise if a ground pattern is formed in a portion facing the semiconductor element. In addition, if the semiconductor element is gold-plated at the portion in contact with the conductive member, the solder is suitable because it is easy to adapt. Further, of the surface of the semiconductor element facing the second circuit board, only the heat generating portion may be in contact with the conductive member.

A metal member having higher thermal conductivity than the conductive member is disposed between the semiconductor element and the second circuit board, and the metal member is supported by the conductive member. If so, the heat radiation effect can be further improved. Further, in the space sandwiched between the first circuit board and the second circuit board, if resin is sealed in a portion other than the conductive member, the first circuit board and the The adhesion strength with the second circuit board can be improved. In addition, the manufacturing method according to the present invention is the first
A flip-chip mounting step of flip-chip mounting the semiconductor element on the circuit board, and an applying step of applying a conductive paste to a position of the second circuit board facing the semiconductor element, A step of placing the first circuit board on the second circuit board so that the first circuit board is placed on the second circuit board so that the first circuit board contacts the conductive paste. A bonding step in which the conductive paste is melted and re-solidified in the state of being formed.

In this way, the flip chip mounting board of the present invention can be manufactured by the existing manufacturing equipment without the need to develop new manufacturing equipment, so that the manufacturing cost of the flip chip mounting board can be reduced. You can
A flip-chip mounting step of flip-chip mounting the semiconductor element on the first circuit board; a separation member bonding step of bonding the separation member to the first circuit board; and a second circuit board on the second circuit board. A first applying step of applying a first conductive paste to a position where the separating member is to be joined, and a first applying step at a position where the first conductive paste should face the semiconductor element on the second circuit board. Second applying step in which the second conductive paste is applied thicker than the second conductive paste, and the separating member is in contact with the first conductive paste, and the semiconductor element is the second conductive paste. The first circuit board is connected to the second paste so as to contact the conductive paste.
A mounting step of mounting the first circuit board on the circuit board, and a step of mounting the first circuit board on the second circuit board.
It is desirable to include a joining step in which the first conductive paste and the second conductive paste are melted and re-solidified.

According to this structure, the adhesion strength between the first circuit board and the second circuit board can be improved and the thickness of the second conductive paste can be adjusted. Further, a flip-chip mounting step of flip-chip mounting the semiconductor element on the first circuit board, and a first conductive paste is applied to a position on the second circuit board that should face the semiconductor element. A first depositing step, a metal plate depositing step of depositing a metal plate on the first conductive paste, and a second depositing second conductive paste on the metal plate. And a mounting step in which the first circuit board is mounted on the second circuit board so that the semiconductor element contacts the second conductive paste, and the first circuit. It is preferable that the method further includes a bonding step in which the conductive paste is melted and resolidified while the board is placed on the second circuit board.

According to this structure, a metal member having higher thermal conductivity than the conductive member is arranged between the semiconductor element and the second circuit board, and the metal member is electrically conductive. Since it can be supported by the member, the heat dissipation efficiency can be further improved. Further, it is preferable that a resin encapsulation step of encapsulating a resin in the gap between the first circuit board and the second circuit board is included after the joining step. With this configuration, the adhesion strength between the first circuit board and the second circuit board can be improved, so that the circuit board as a whole can be made stronger.

A radio device according to the present invention is characterized by including the flip chip mounting substrate as described above. With this configuration, the wireless device itself can be reduced in size and weight along with the reduction in size and weight of the flip-chip mounting substrate, and since the heat dissipation efficiency of the flip-chip mounting substrate is high, it is caused by overheating of the semiconductor element. It is possible to avoid malfunction of the wireless device that operates.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) An embodiment of a mobile phone device according to the present invention will be described. The flip-chip mounting substrate according to the present invention is applied to the mobile phone device.

(Overall Structure) The mobile phone device according to the present embodiment has a main feature of a flip-chip mounting board which is a circuit board on which flip-chips are mounted, and therefore the description of the outer shape is omitted. FIG. 1 is a plan view schematically showing the outer appearance of a flip-chip mounting board included in the mobile phone device according to the present embodiment. As shown in FIG. 1, the flip-chip mounting substrate 1 has a structure in which circuit elements 15a to 15q such as IC chips are mounted on a multilayer printed circuit board 10 at a high density.

A circuit element 15a is provided on the printed circuit board 10.
In addition to 15q, a jack 14a for connecting a headset, a connector 14b for data communication with a device such as a personal computer, or a vibrator 12 for notifying an incoming call by vibration is mounted. Has been done. The electrode terminal 13 is the flip chip mounting substrate 1.
It is a terminal for connecting a battery pack which is a secondary battery for supplying electric power to the. The battery pack receives power from the outside of the mobile phone device via an electrode terminal (not shown) provided in the connector 14b to store electricity.

An LCD (Liquid Crystal Display) unit is mounted on the other surface (not shown) of the printed circuit board 10, and various displays are performed by the LCD unit. In addition, a key electrode is formed on this surface with a copper pattern and is combined with a key button (not shown) to receive a key input. That is, when the key electrode and the key button come into contact with each other, a current flows between the key electrode and the key button, and the key input is detected by detecting this current.

On the printed circuit board 10, a silicon substrate 11 on which a wireless circuit of the mobile phone device according to this embodiment is mounted is connected. FIG. 2 shows a silicon substrate 11
3 is a plan view schematically showing the outer appearance of the surface of the printed circuit board facing the printed circuit board 10. FIG. The wireless transmission IC chip 111a, the wireless reception IC chip 111b, and the like are flip-chip mounted on the silicon substrate 11. This wireless transmission IC
The chip 111a is characterized by having the largest amount of heat generation among the members constituting the mobile phone device.

The silicon substrate 11 has these ICs.
A resistance element and a capacitance element which are circuit elements of peripheral circuits of the chips 111a to 111c are integrated. Silicon substrate 1
Ball electrodes 112a to 112t are arranged at the peripheral edge of the first electrode. The ball electrodes 112a to 112t are solder ball electrodes, and are electrically connected to the silicon substrate 11 and the printed circuit board 10 by being joined to the copper pattern (wiring pattern) formed on the printed circuit board 10. .

The ball electrodes 112a to 112t are mounted on the silicon substrate 11 by a known ball placer method. For example, flux is applied to the surface of the silicon substrate 11 on which the ball electrodes 112a to 112t are mounted, solder balls are mounted, then the solder is melted in a nitrogen atmosphere (reflow process), and the silicon substrate 11 is washed to remove the flux. Then, the ball electrodes 112a to 112a are formed on the silicon substrate 11 by a method of drying after removing the
12t is implemented.

Next, the printed circuit board 10 and the silicon substrate 11
The connection state of will be described. FIG. 3 is a view showing a cross section of the flip-chip mounting board 1 taken along the alternate long and short dash line AA, showing the structure of the flip-chip mounting board according to the present invention. One-dot chain line AA in FIG.
1 shows a position corresponding to the one-dot chain line AA in FIG. 1 and crosses the ball electrode 112g, the wireless transmission IC chip (hereinafter, simply referred to as “IC chip”) 111a, and the ball electrode 112t.

Now, referring to FIG. 3, the silicon substrate 11 has the printed circuit board 1 through the ball electrodes 112g and 112t.
0 is electrically connected to the ball electrode 112g, 1
12t is soldered to the printed circuit board by solders 18a and 18c, respectively. On the silicon substrate 11, the IC chip 111a has minute projection electrodes 111a1a to 111a.
They are electrically connected via 1g, and this connection is made by flip-chip mounting the IC chip 111a using the polymer encapsulant 111a2.

Ball electrode 112 on printed circuit board 10
Copper lands 17a and 17c which can be soldered are respectively patterned at positions where g and 112t are joined, and the ball electrodes 112g and 1c are soldered with solder lands 18a and 18c, respectively.
12t is joined. A copper land 17b is also provided on the printed circuit board 10 at a position facing the IC chip 111a.
Is patterned, and the copper land 17b is solder 18
The IC chip 111a is soldered by b.

The portions of the printed board 10 where the copper lands are not patterned are covered with insulating coatings 16a to 16d to prevent short circuits. The coatings 16a to 16d are formed by applying an insulating paint on the printed circuit board 10.
For reference, each dimension according to FIG. 3 will be described. The thickness of the silicon substrate 11 is about 300 μm. Ball electrode 112
The diameters of g and 112t are each about 500 μm. The distance from the printed circuit board 10 to the IC chip 111a is about 3
It is 00 μm. The distance from the IC chip 111a to the ball electrodes 112g and 112t is about 1 mm or more.

Conventionally, since the resin material having a low thermal conductivity is interposed between the IC chip 111a and the printed circuit board 10, the heat generated by the IC chip 111a is not easily released to the outside, and the IC chip is not released. 111a was a cause of malfunction due to overheating. On the other hand, if the solder 18b having high thermal conductivity is interposed between the IC chip 111a and the printed circuit board 10 as described above, the IC chip 1
The heat generated by 11a is efficiently radiated to the printed circuit board 10 via the solder 18b.

Further, as shown in FIG. 3, the printed circuit board 1
On the surface of the side of 0 facing the silicon substrate 11, I
Copper lands 18 are provided on all parts facing the C chip 111a.
b is formed. The copper land 17b is grounded to form a so-called ground pattern. In addition, solder 18
b is also at the ground potential and has an effect of preventing noise from being superimposed on the signal line of the IC chip.

Needless to say, the IC chip 111
In the case of a, the signal line is not exposed to the surface on the printed circuit board 10 side as in the case of a normal IC chip, so there is no concern that a short circuit will occur in the circuit due to the solder 18b. (Manufacturing Method) Next, a manufacturing method of the flip chip mounting substrate 1 in which the silicon substrate is connected to the printed board as described above will be described. FIG. 4 is a schematic diagram showing each step of the manufacturing method.

First, as shown in FIG. 4A, solderable copper lands 17a and 17c are patterned on the printed circuit board 10 at positions where the ball electrodes 112g and 112t are to be joined. Further, the copper land 17b is similarly patterned at the position where the IC chip 111a is to be joined. At this time, the copper lands 17a to 17c are also plated with gold.

Next, as shown in FIG. 4 (b), solder pastes 18a and 18b are deposited on the copper lands 17a and 17c on the printed circuit board 10 where the ball electrodes 112g and 112t are to be joined. . This may be done by screen printing, for example. That is, first, the aluminum plate is punched according to the shape of the portion to which the solder pastes 18a and 18c are to be applied.

The aluminum plate is placed on the printed circuit board 10 at a predetermined position. Then, after applying the solder paste from the aluminum plate, the aluminum plate may be removed. In the present embodiment, the aluminum plate has a thickness of 100 μm so that the solder pastes 18a and 18b have a thickness of 100 μm.

Then, as shown in FIG. 4C, by screen printing on the copper land 17b on the printed circuit board 10 where the IC chip 111a is to be joined,
The solder paste 18b is applied. As for this deposit,
For example, screen printing may be performed as described above. In the present embodiment, the solder paste 18b needs to have a thickness of 300 μm so that the solder paste 18b reaches the IC chip 111a. Therefore, when screen printing is performed as described above, it is desirable that the aluminum plate has a thickness of 300 μm.

Then, as shown in FIG. 4D, the silicon substrate 11 is held by, for example, vacuum tweezers,
It is placed at a predetermined position on the printed board 10. In addition,
An IC chip 111a is flip-chip mounted in advance on the silicon substrate 11. In addition, the ball electrode 112g,
112t is also bonded to the silicon substrate 11 in advance. In this state, the solder paste 18 is formed by the reflow method.
When a to 18c are melted and re-solidified, finally, as shown in FIG.
The flip chip mounting substrate as shown in (e) is completed.

According to such a manufacturing method, it is possible to manufacture the flip chip mounting board according to the present invention by utilizing the existing manufacturing equipment, and further to manufacture the flip chip mounting board 1. Therefore, no new investment is required for manufacturing equipment, so that it is possible to suppress the manufacturing cost of the mobile phone device according to the present embodiment and provide an inexpensive mobile phone device.

(Second Embodiment) Next, a portable telephone device according to a second embodiment will be described. The mobile phone device according to the present embodiment has substantially the same configuration as the mobile phone device according to the first embodiment, and is different only in the structure of the flip-chip mounting substrate. A different point from the mobile phone device according to the first embodiment, that is, a structure of a flip-chip mounting substrate will be described exclusively.

(Overall Structure) The flip-chip mounting substrate according to this embodiment is an IC mounted on a silicon substrate.
In order to more efficiently conduct and dissipate the heat generated by the chip to the printed circuit board than in the first embodiment, the structure described below is adopted.

FIG. 5 is an enlarged view of a cross section of the flip chip mounting substrate 2 according to this embodiment. The flip-chip mounting substrate 2 has a structure in which the silicon substrate 21 is bonded to the printed circuit board 20 via ball electrodes (not shown), as in the first embodiment.
Further, the silicon substrate 21 has a wireless transmission IC chip 21.
1a is flip-chip mounted via minute protruding electrodes 211a1a to 211a1d.

IC chip 211a on the printed circuit board 20
A copper land 27b that can be soldered is patterned at a position facing the. In the present embodiment, the copper plate 29 is arranged between the copper land 27b and the IC chip 211a. Then, the IC chip 211a and the copper plate 29
Are bonded by solder 27b, and the copper plate 29 and copper land 27b are bonded by solder 28c.

In this way, the copper land 27b and the IC chip 2 are
If the copper plate 29 is arranged between the 11a, the heat conductivity of copper is higher than that of the solder, so that the heat generated by the IC chip 211a is more efficient than that in the first embodiment and the printed circuit board 20 Can be conducted to. Therefore, the heat dissipation efficiency of the flip chip mounting substrate 2 as a whole can be improved.

(Manufacturing Method) Next, a method of manufacturing the flip chip mounting substrate according to the present embodiment will be described. FIG. 6 is a schematic diagram showing each step of the method of manufacturing the flip chip mounting substrate according to the present embodiment. First, the first
In the same manner as in the above embodiment, solderable copper lands 27a and 27c are patterned on the printed circuit board 20 at the places where the ball electrodes 212g and 212t are to be joined, and at the places where the IC chip 211a is to be joined. Similarly, the copper land 27b is patterned. Gold plating is further applied to the patterned copper lands 27a to 27c (FIG. 6A).

Next, as shown in FIG. 6B, a solder paste 28c is deposited on the copper lands 27b. This may be performed, for example, by screen printing as described in the first embodiment. Then, the copper plate 29 is placed on the solder pace 28c thus deposited (FIG. 6C).
This copper plate 28 is solder paste 28 by the reflow method.
When c is melted and solidified, the printed circuit board 2
Soldered to zero.

Subsequently, as shown in FIG. 6D, after the solder pastes 28a and 28d are applied onto the copper lands 27a and 27c, the solder paste 28b is applied onto the copper plate 29 (see FIG. 6E). )). These processes may also be performed by screen printing, for example, and the solder pastes 28a and 28d
It is preferable to use aluminum plates having different thicknesses for the solder paste 28b and the solder paste 28b. The thickness of this aluminum plate is determined according to the thickness of the solder paste.

After the solder paste is deposited on the printed circuit board 20 as described above, the silicon substrate 21 is held on the printed circuit board 20 by vacuum tweezers, for example, as shown in FIG. 6 (f). It is placed according to a predetermined position. It should be noted that the IC chip 21 is previously formed on the silicon substrate
1a is flip-chip mounted, and the ball electrode 11
2g and 112t are also formed on the silicon substrate 11 by a known method.
Is joined to.

Finally, the solder paste 2 is applied by the reflow method.
When 8a, 28b, and 28d are melted and re-solidified, the printed circuit board 20 and the silicon substrate 21 are bonded to each other, as shown in FIG.
A flip chip mounting substrate as shown in (g) is completed. According to such a manufacturing method, as in the first embodiment, the existing manufacturing equipment can be utilized to manufacture the flip-chip mounting substrate according to the present invention. Flip chip mounting boards can be manufactured without investment. Therefore, it is possible to suppress the manufacturing cost of the flip chip mounting substrate and to provide the mobile phone employing the flip chip mounting substrate at a low cost.

(Modifications) The present invention has been described above based on the embodiments. However, it goes without saying that the present invention is not limited to the above-mentioned embodiments, and the following modifications are carried out. be able to. (1) In the above embodiment, the case where the present invention is applied to a mobile phone has been described, but instead of this, the following may be applied. That is, IEEE802.11a and IEEE8
Wireless LAN device and Bluetooth compliant with standards such as 02.11b
If it is applied to a wireless device that has a wireless communication circuit such as a wireless device conforming to the specifications of (registered trademark) and has a demand for downsizing, it has the effect of improving the heat dissipation efficiency as described above. be able to.

Also, a PCMCIA (Personal Computer)
According to the present invention, it is possible to improve the heat dissipation efficiency while suppressing the height of the flip-chip mounting substrate even when providing a wireless device that complies with the standard (PC Card Standard) established by Memory Card International Association). it can. (2) In the above embodiment, the silicon substrate and the printed circuit board are bonded via the ball electrode and the IC chip, but in addition to this, the following may be performed.

FIG. 7 is a view showing a cross section of the flip chip mounting substrate 3 of the mobile phone according to this modification. As shown in FIG. 7, the flip chip mounting substrate 3 according to the present modification includes the same flip chip mounting substrate as the flip chip mounting substrate 1 according to the first embodiment, and further includes a silicon substrate and a printed circuit board. Is a polymer mounting agent 39a to 39d
Are joined by. This polymer mounting agent 39a-3
9d is obtained by pouring a polymer encapsulant into the flip-chip mounting substrate 1 according to the first embodiment from the periphery of the silicon substrate 11 and filling and curing it by heat treatment.

As the polymer encapsulant, for example, epoxy resin or the like is preferably used. By doing so, the adhesion strength between the silicon substrate 31 and the printed circuit board 30 can be increased, so that the flip chip mounting substrate 3
The mechanical strength of can be improved. This is
The present invention exerts a great effect when the present invention is applied to a device such as a mobile phone that requires high environment resistance.

Similarly, for the flip-chip mounting substrate according to the second embodiment, if the polymer encapsulant is filled and cured from the periphery of the silicon substrate 21, the silicon substrate 21 and the printed board are printed. The adhesion strength with the substrate 20 can be increased, and the mechanical strength of the flip chip mounting substrate 2 can be improved. Further, as a similar modification, when a plurality of IC chips are mounted on a silicon substrate, only the IC chips having a particularly large heat generation amount may be connected to the printed circuit board by soldering, or regardless of the heat generation amount. Instead, all the IC chips may be connected to the printed board by soldering. Of course, when only one IC chip is mounted on the silicon substrate, the IC chip may be connected to the printed board by soldering, and in any case, the effect of the present invention can be obtained.

(3) In the above embodiment, I
Although the solder paste is brought into contact with the entire surface of the C chip facing the printed circuit board, it may be replaced with the following. That is, the solder paste may be brought into contact only with a portion of the IC chip where a transistor is formed, or the like, which generates a particularly large amount of heat and therefore requires more heat dissipation. FIG. 8 is a diagram showing a cross section of a flip-chip mounting substrate according to this modification. As shown in FIG. 8, even if the solder paste 48b is brought into contact only with a portion of the IC chip 411a that generates a particularly large amount of heat, the heat generated by the IC chip 411a is conducted to the printed circuit board 40 more efficiently than in the conventional case, and the heat radiation is performed. Can be planned.

Further, in this way, the solder paste 4
Since the area in which 8b contacts the IC chip 411a and the printed circuit board 40 can be reduced, the solder paste 48
It is possible to reduce the possibility that the circuit b will accidentally contact the electrode or the wiring pattern which should not be in contact, and a short circuit will occur in the circuit. Therefore, it is possible to prevent the malfunction caused by the short circuit of the circuit and improve the quality of the flip chip mounting substrate.

In this modification, regardless of the presence or absence of contact with the solder paste, as in the above-described embodiment, one of the main surfaces of the printed circuit board 46 facing the silicon substrate 40 is connected to the IC chip 42. Copper lands 44b are formed over the entire facing portions. By doing so, the operation of the IC chip 42 can be stabilized as in the above-described embodiment.

Further, as in the second embodiment, if a copper plate is inserted into the solder paste 48b between the IC chip 411a and the printed board 40, the heat dissipation efficiency can be further improved. . Further, in order to compensate for the decrease in the adhesion strength between the silicon substrate 40 and the printed circuit board 46, which is reduced by the area to be joined by the solder paste, for example, as in the modification (1), the silicon substrate 41 and A polymer encapsulant may be filled between the printed board 40 and the two boards to fix them together.

(4) In the above embodiment, the IC chip was flip-chip mounted on the silicon substrate, but instead of this, the following may be carried out. That is,
The IC chip may be flip-chip mounted on a substrate whose base material is glass, quartz, sapphire, ceramics, or the like. Even if such a base material is used, patterning can be performed by a method of manufacturing a fine semiconductor using thin film vapor deposition technology, etc., as in the case of using silicon as a base material, and a capacitive element, an inductor, a resistive element, etc. can be accurately incorporated. Since it is possible to realize a semiconductor substrate, it is possible to reduce the size and weight while achieving the effects of the present invention.

(5) Although not particularly mentioned in the above embodiment, when flip-chip mounting an IC chip on a silicon substrate, a stud bump method, a method using an anisotropic conductive film, and a solder bump connection method are used. A known construction method such as the above may be used, and the present invention can exert the effect regardless of the construction method for flip-chip mounting the IC chip.

(6) In the above embodiment, the silicon substrate and the printed circuit board are joined by using the ball electrode made of solder, but instead of this, the following may be done. That is, the silicon substrate and the printed circuit board may be joined by using copper balls, metal-coated resin balls, or the like. Even when these are used, the effect of the present invention does not change. Further, the present invention can exert the effect even when the silicon substrate and the printed circuit board are connected by an electrode other than the ball electrode.

(7) In the above-described second embodiment, the copper plate is used to more efficiently conduct heat from the IC chip 211a to the printed circuit board 20, but a metal plate other than copper is used. Is also good. Solder, etc.
As long as the metal has a higher thermal conductivity than the member connecting the C chip 211a and the printed board, the heat dissipation efficiency can be further improved even if the metal plate is made of any metal.

(8) In the above embodiment, I
Although the solder paste is used when connecting the C chip and the printed circuit board, a silver paste may be used instead. Alternatively, a gold paste, a copper paste, or an aluminum paste may be used.
It is more preferable to use a conductive paste having improved thermal conductivity by adding an appropriate filler, as in the technique disclosed in Japanese Patent Publication No. 347320.

Further, when the flip chip mounting substrate according to the present invention is manufactured by using the silver paste, the silver paste may be supplied to the printed circuit board by jetting the silver paste from the nozzle of the dispenser. In this case, the thickness of the silver paste on the printed board can be changed by adjusting the injection amount of the nozzle. (9) In the above embodiment, when the IC chip and the printed board are connected, the IC chip is directly contacted with the solder, but instead of this, the following may be performed. That is, the entire surface of the IC chip facing the printed circuit board is gold-plated, or at least the portion of the IC chip to be soldered is gold-plated, and the IC chip is soldered through the gold plating. Also good.

By doing so, since the solder is in good contact with the gold, the adhesion between the solder and the IC chip can be improved, and thus the adhesion strength between the silicon substrate and the printed circuit board can be improved. (10) In the second embodiment, when manufacturing the flip chip mounting substrate 2, the solder paste 2 is used.
After placing the copper plate 29 on 8c, solder paste 28
Although it has been stated that a and 28d are deposited on the copper lands 27a and 27c, instead of this, the following may be applied.

That is, first, the solder paste, 28a,
28c, 28d simultaneously with copper lands 27a, 27b, 27
It is applied on c. Next, the copper plate 2 is placed on the solder pace 28c.
9 is placed, and the solder paste 28b is further applied onto the copper plate 29. After that, the silicon substrate 21 is placed at a predetermined position, and the solder pastes 28a to 28a are formed by the reflow method.
d is melted and resolidified.

The flip-chip mounting substrate 2 may be manufactured by the procedure as described above, which makes it possible to perform screen printing in comparison with the manufacturing method described in the second embodiment. Since the number of required aluminum plates can be reduced, the manufacturing cost of the flip chip mounting substrate 2 can be reduced.

[0063]

As described above, according to the present invention,
A first circuit board on which semiconductor elements are flip-chip mounted; and a second circuit board on the first circuit board facing the main surface on which the semiconductor elements are flip-chip mounted. Since the semiconductor element and the second circuit board are connected via a conductive member, the heat generated by the semiconductor element flip-chip mounted on the first board is generated. The heat can be efficiently dissipated by conducting the heat to the second substrate. Further, by setting the conductive member to the ground potential, it is possible to reduce noise on the semiconductor element.

[Brief description of drawings]

FIG. 1 is a plan view schematically showing an external appearance of a flip-chip mounting board included in a mobile phone device according to a first embodiment.

FIG. 2 is a plan view schematically showing the outer appearance of the surface of the silicon substrate 11 constituting the flip-chip mounting substrate 1 that faces the printed circuit board 10.

3 is a diagram showing a cross section of the flip-chip mounting substrate 1 taken along the alternate long and short dash line AA shown in FIG.

FIG. 4 is a schematic view showing each step of the method of manufacturing the flip chip mounting substrate 1 according to the first embodiment.

FIG. 5 is an enlarged view showing a cross section of a flip chip mounting substrate 2 according to a second embodiment.

FIG. 6 is a schematic view showing each step of the method of manufacturing the flip chip mounting substrate 2 according to the second embodiment.

FIG. 7 is a flip-chip mounting substrate 3 according to a modification (2).
It is a figure showing one section and showing the structure.

FIG. 8 is a flip-chip mounting substrate 4 according to Modification (3).
It is a figure showing one section and showing the structure.

FIG. 9 is a view showing a cross section of a microchip module assembly according to Japanese Patent Laid-Open No. 8-255965.

[Explanation of symbols]

10, 20, 30 etc. Printed circuit board 11, 21, 31 etc. Silicon substrate 111a, 211a, etc. IC chips 112a to 112t, etc. Ball electrode 16a-16d etc. Insulating film 17a to 17c, etc. Gold-plated copper land 18a-18c, etc. Solder 29 Copper plate

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05K 3/34 507 H05K 3/34 507C 3/36 3/36 B (72) Inventor Kazuhiro Yawata Kadoma Osaka Prefecture 1006, Kadoma, Ichimaji Matsushita Electric Industrial Co., Ltd. F-term (reference) RR10

Claims (14)

[Claims] 1. A first circuit board on which a semiconductor element is flip-chip mounted, and a second circuit board that is arranged so as to face a main surface of the first circuit board on which the semiconductor element is flip-chip mounted. A flip-chip mounting board comprising the circuit board according to claim 1, wherein the semiconductor element and the second circuit board are connected via a conductive member. 2. The flip chip mounting substrate according to claim 1, wherein the conductive member is formed by solidifying a solder paste or a silver paste. 3. The flip chip according to claim 1, wherein the first circuit board and the second circuit board are separated from each other by a separating member by a distance larger than a thickness of the semiconductor element. Mounting board. 4. The separating member is a ball electrode having a diameter larger than the thickness of the semiconductor element, and the first circuit board and the second circuit board are electrically connected by the ball electrode. The flip chip mounting substrate according to claim 3, wherein the flip chip mounting substrate is provided. 5. The flip chip mounting board according to claim 1, wherein a ground pattern is formed on a portion of the second circuit board facing the semiconductor element. 6. The flip chip mounting substrate according to claim 1, wherein the semiconductor element is gold-plated at a portion in contact with the conductive member. 7. The flip chip mounting board according to claim 1, wherein only a heat generating portion of a surface of the semiconductor element facing the second circuit board is in contact with the conductive member. 8. A metal member having thermal conductivity higher than that of the conductive member is disposed between the semiconductor element and the second circuit board, and the metal member is the conductive member. The flip chip mounting substrate according to claim 1, which is supported. 9. The resin is sealed in a portion of the space sandwiched between the first circuit board and the second circuit board other than the conductive member. The flip chip mounting substrate described. 10. The method of manufacturing a flip-chip mounting board according to claim 1, wherein a flip-chip mounting step of flip-chip mounting the semiconductor element on the first circuit board, and the second circuit board. A deposition step in which a conductive paste is deposited at a position facing the semiconductor element, so that the semiconductor element is in contact with the conductive paste,
A placing step in which the first circuit board is placed on the second circuit board; and a step of placing the conductive paste in a state where the first circuit board is placed on the second circuit board. A joining step of melting and re-solidifying. 11. The method of manufacturing a flip-chip mounting board according to claim 3, wherein the flip-chip mounting step of flip-chip mounting the semiconductor element on the first circuit board comprises: A separating member joining step of joining the separating member; a first attaching step of attaching a first conductive paste to a position on the second circuit board where the separating member is to be joined; A second deposition step of depositing a second conductive paste thicker than the first conductive paste at a position on the second circuit board that should face the semiconductor element; A mounting step in which the first circuit board is mounted on the second circuit board so as to contact the first conductive paste and so that the semiconductor element contacts the second conductive paste; , The first And a bonding step in which the first conductive paste and the second conductive paste are melted and re-solidified while the second circuit board is placed on the second circuit board. And manufacturing method. 12. The method of manufacturing a flip-chip mounting board according to claim 8, wherein a flip-chip mounting step of flip-chip mounting the semiconductor element on the first circuit board, the second circuit board A first depositing step of depositing a first conductive paste at a position to face the semiconductor element, and a metal plate placing step of placing a metal plate on the first conductive paste. And a second conductive paste deposited on the metal plate.
And a mounting step in which the first circuit board is mounted on the second circuit board so that the semiconductor element contacts the second conductive paste, and the first circuit And a bonding step in which the conductive paste is melted and resolidified while the substrate is placed on the second circuit board. 13. A resin encapsulation step of encapsulating resin in a gap between the first circuit board and the second circuit board after the joining step.
13. The manufacturing method according to claim 12. 14. A wireless device comprising the flip chip mounting substrate according to claim 1. Description: