JPH09330994A - Semiconductor device - Google Patents

Abstract

(57) Abstract: A tape BGA package for mounting an integrated circuit chip by a wire bonding method is realized to be thin. The present invention relates to a tape BGA package in which an integrated circuit chip is mounted on a flexible insulating substrate having a plurality of solder bumps formed on one surface side. The semiconductor device 1 has a reinforcing plate 9 on a flexible insulating substrate 3 having an opening 3a. The integrated circuit chip 2 is mounted on the integrated circuit chip 2 with the surface provided with the electrode pad 2a facing the reinforcing plate. An opening 9a is formed at a position of the reinforcing plate 9 corresponding to the electrode pad. The electrode pad 2a and the inner lead 4a are electrically connected by the conductor wire 6 through this opening. A resin is sealed so as to cover at least this conductor wire. Since the conductor wire 6 does not extend above the chip, the package can be thinned accordingly. The reinforcing plate on which the integrated circuit chip is mounted also functions to improve its heat dissipation.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a semiconductor device,
In particular, the present invention relates to a tape BGA package which is suitable for thinning the package and has excellent heat dissipation of a semiconductor integrated circuit chip to be mounted.

[0002]

2. Description of the Related Art With the demand for miniaturization of semiconductor integrated circuit packages and increase in the number of pins, a conventional QFP (Quad Flat Packag) has been developed.
BGA packages are attracting attention as alternatives to e) and TCP (Tape Carrier Package). BGA (Ball Gr
The id array) is a surface-mount type package in which solder bumps, which are connection terminals, are two-dimensionally arranged on the bottom surface side of a substrate on which an integrated circuit chip is mounted. Since the connection terminals are arranged two-dimensionally, the terminal pitch can be 1 mm or more even if the number of pins is increased, and one of the advantages of BGA is that it can be easily mounted using the conventional batch reflow mounting technology. Is.

Tape BGA is a type of BGA package.
There is a package. In this structure, a substrate on which an integrated circuit chip is mounted is composed of a polyimide flexible tape like TCP. The chips on the tape are covered and sealed with resin. The tape BGA is superior to the BGA package using a ceramic substrate in terms of mass productivity and workability.

Conventionally, flip-chip or wire bonding methods have been used to mount the integrated circuit chip on the tape BGA package. In the flip-chip method, conductor bumps such as solder and gold are formed on the electrode pads on the main surface of the integrated circuit chip, the main surface of the chip, that is, the surface on which the circuit is formed faces the substrate side, and the electrode pads are connected to the conductor bumps. This is a method of directly bonding to the inner leads on the substrate via The wire bonding method is a method in which an integrated circuit chip is mounted on a substrate with its main surface facing upward, and electrode pads and inner leads on the substrate are connected by a conductor wire such as a gold wire.

The flip chip method is excellent in that the package is thin, but the relative positions of the inner lead and the electrode pad must be accurate, and these designs and mounting of the integrated circuit chip are required. The position accuracy of is severe. Furthermore, a process for forming a conductor bump on the electrode pad is required. On the other hand, the wire bonding method has advantages that the inner leads and the electrode pads are connected via the conductor wires, so that the positional accuracy thereof is gentler than that of the flip chip method and the bump forming step is not necessary. However, the wire bonding method is more disadvantageous than the flip chip method in terms of thinning the package. That is, the conductor wire is
In order to avoid contact with the chip, it extends upward from the electrode pad surface and then curves from there to the inner lead. The resin layer that determines the thickness of the package must be provided so as to completely cover the conductor wire, and as a result, it has been difficult to reduce the thickness of the package beyond a certain range.

Further, in the tape BGA package, there is a problem that needs to be solved, like the package in which other highly integrated chips are mounted. It is a problem of heat dissipation of the integrated circuit chip mounted. With the high integration of chips, the problem of heat dissipation of the package becomes more important. In the tape BGA, the integrated circuit chip has one side of insulating polyimide tape,
The other surface is covered with an insulating resin. Therefore, the heat generated from the chips must be dissipated into the outside air via these. Although these insulating materials have excellent performance in terms of protecting the chip from the outside polluted environment, they do not function well in terms of radiating the heat of the chip to the outside.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to realize a tape BGA package which mounts an integrated circuit chip by a wire bonding method and realizes its thinning.

Another object of the present invention is to provide a tape BGA package having a low thermal resistance which efficiently dissipates heat generated in an integrated circuit chip to the outside.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a semiconductor device having an integrated circuit chip mounted on a flexible insulating substrate having a plurality of solder bumps formed on one surface side. The semiconductor device of the present invention has a reinforcing plate on a flexible insulating substrate having an opening formed in at least a part of a position where an integrated circuit chip is mounted. The reinforcing plate is basically for reinforcing a flexible insulating substrate that does not have sufficient strength as a package. The integrated circuit chip is mounted on the reinforcing plate with the surface provided with the electrode pad facing the reinforcing plate. An opening is formed in the reinforcing plate at a position corresponding to the electrode pad. The electrode pad faces the opening side of the flexible insulating substrate through this opening, and the electrode pad and the inner lead in the conductor pattern on the flexible insulating substrate are spatially connected to each other.
The electrode pad and the inner lead are electrically connected by a conductor wire through this opening. A resin is sealed so as to cover at least this conductor wire.

The electrode pad of the integrated circuit chip is directed to the reinforcing plate side, and the conductor wire extending from the electrode pad reaches the flexible insulating substrate on the opposite side from the opening of the reinforcing plate and is connected to the inner lead. Therefore, the conductor wire does not protrude above the integrated circuit chip, so that the resin layer on the integrated circuit chip mounting side can be thinned.

The conductor pattern formed on the flexible insulating substrate may be formed on the surface on which the solder bumps are formed, or on the surface opposite to the surface. When the conductor pattern is formed on the surface opposite to the surface of the solder bump, the solder bump and the outer lead of the conductor pattern are electrically connected to each other through a via hole formed in the flexible insulating substrate. Further, the inner lead is extended into the opening of the reinforcing plate or the opening edge of the flexible insulating substrate is extended so that the inner lead is not covered by the reinforcing plate provided on the flexible insulating substrate. You need to do it.

When the conductor pattern is formed on the surface of the flexible insulating substrate on which the solder bumps are to be formed, the conductor wires are somewhat protruded from the substrate surface toward the solder bumps. The resin layer covering the conductor wires further bulges toward the solder bumps. In order to reduce the solder bump pitch and increase the number of package mounting pins, it is necessary to reduce the solder bump diameter. The bulge on the solder bump side of the resin layer prevents this.

Therefore, according to the present invention, the region of the reinforcing plate on which the integrated circuit chip is mounted and its periphery are recessed on the side opposite to the side of the flexible insulating substrate, and the flexible insulating substrate is arranged along this recess. By arranging them, the position of the inner lead can be arranged closer to the reinforcing plate than the surface of the flexible insulating substrate.

In the structure of the present invention, the area of the reinforcing plate under the integrated circuit chip is continuous with the area of the other reinforcing plate through some bridges due to the opening formed in the reinforcing plate.
The heat of the integrated circuit chip is dissipated from the area of the reinforcing plate to which it is in contact, through the bridge, to the area of the surrounding reinforcing plate. The reinforcing plate is preferably made of a metal having a high thermal conductivity, such as copper, in order to obtain a certain strength and to efficiently radiate the heat of the integrated circuit chip to the outside. It is possible to further provide a heat sink on the reinforcing plate and the integrated circuit chip in order to improve heat dissipation efficiency.

The present invention can also adopt a heat dissipation structure in which some of the solder bumps formed on the flexible insulating substrate are thermally connected to the reinforcing plate. The heat transmitted from the integrated circuit chip to the reinforcing plate is dissipated through the solder bumps to the conductor pattern on the substrate on which the package is mounted. The solder bumps selected for heat dissipation are
It can be used for the power supply of the integrated circuit chip, that is, for supplying the power supply potential or the ground potential. In this case, the reinforcing plate is kept at the same potential as the power source or the ground potential to achieve impedance matching.

The present invention can also be configured such that a heat sink is provided on the flexible insulating substrate instead of the reinforcing plate. A recess is formed on the surface of the heat sink facing the flexible insulating substrate. In the recess, the integrated circuit chip is housed and the region of the flexible insulating substrate where the inner leads are formed is located. In this case, the heat sink can be made of a thin metal plate.

Further, in the present invention, it is possible to adopt a structure in which the integrated circuit chip is fixed to the reinforcing plate surface from the opening side formed in the flexible insulating substrate. Integrated circuit chips
It is located on the same side as the side on which the flexible insulating substrate is provided with respect to the reinforcing plate. Therefore, the electrode pad of the integrated circuit chip and the inner lead of the conductor pattern, which are electrically connected by the conductor wire, are located on the same side with respect to the reinforcing plate. Therefore, the conductor wire does not come out from one side to the other side of the opening of the reinforcing plate, but extends from the electrode pad, is curved in the opening and returns to the original direction, and is connected to the inner lead. In this case, the integrated circuit chip can be thermally connected to the conductor pattern of the substrate on which the package is mounted. The heat of the integrated circuit chip is directly radiated to the mounting substrate side, and the heat radiation of the package becomes extremely good.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 in which the present invention is applied
The tape BGA package corresponding to 56 pins is shown. The semiconductor device 1 has a semiconductor integrated circuit chip 2 mounted in the center of a rectangular package. FIG. 1 is a perspective view seen from the mounting surface side showing a part of the package in a cutaway state, and FIG. 2 is a sectional view thereof. The semiconductor device 1 has a layer of a flexible insulating substrate 3 made of polyimide. The flexible insulating substrate 3 has an opening 3a at the center thereof which is slightly larger than the outer shape of the integrated circuit chip 2. A conductor pattern 4 is printed on the lower surface side of the flexible insulating substrate 3. This situation is best represented in a simplified state in FIG. 4, which is an exploded perspective view of the device seen from below. Many conductor patterns 4
Has one end extending toward the central opening 3a. This inner end of the conductor pattern is called an inner lead 4a. Each inner lead 4a is electrically connected to each electrode pad 2a of the integrated circuit chip 2 to be mounted via a conductor wire 6. The other end of the conductor pattern 4 extends to the position of the solder bump 5 formed on the lower surface of the flexible insulating substrate 3. Connect the outer end of the conductor pattern to the outer lead 4
Called b. The solder bumps 5 are joined to the outer leads 4b in the final step of the manufacturing stage. On the lower surface of the flexible insulating substrate 3, the inner lead 4a and the outer lead 4b are exposed, a layer 7 of solder resist is formed, and the conductor pattern 4 is covered.

A reinforcing plate 9 is adhered to the upper surface of the flexible insulating substrate 3 via an adhesive layer 8. In one embodiment,
On a polyimide film having a thickness of about 0.1 mm, a copper plate having a thickness of about 0.125 mm as a reinforcing plate was laminated with an adhesive layer of about 0.05 mm interposed therebetween. The reinforcing plate 9 is formed with four openings 9a,
An island is formed in the center of the reinforcing plate 9 by these openings 9a. Hereinafter, this island portion is referred to as a die pad 9b.
The integrated circuit chip 2 is mounted on the die pad 9b with its main surface facing downward. The integrated circuit chip 2 is fixed on the die pad 9b via a silver paste or a heat conductive adhesive 10. Here, the die pad 9b has a size slightly smaller than the outer shape of the integrated circuit chip 2. That is, with the integrated circuit chip 2 mounted on the die pad 9b, the outer edge of the die pad 9b is located inside the electrode pad 2a formed on the peripheral portion of the main surface of the integrated circuit chip 2. Therefore, when the reinforcing plate 9 on which the integrated circuit chip 2 is mounted is viewed from below, the electrode pad 2a can be seen from the opening 9a.

The portion of the die pad 9b and the surrounding portion of the reinforcing plate 9d are connected by four bridges 9c. The bridge 9c is important in the sense of having the following two functions in addition to the role of fixing and supporting the integrated circuit chip in the manufacturing of packaging. First, the bridge 9c has a structural function of supporting the die pad 9b with respect to the surrounding reinforcing plate 9d. Bridge 9c
If the surrounding reinforcing plate 9d and the die pad 9b are not integrated with each other, the integrated circuit chip 2 mounted on the die pad 9b is in an unstable state of being supported by the resin layer 11, and the conductor wire 6 There is a risk of disconnection and cracking of the package. Secondly, the bridge 9c has a function of releasing heat generated from the integrated circuit chip 2 onto the surrounding reinforcing plate 9d. The heat of the integrated circuit chip 2 is transmitted to the die pad 9b and the four bridges 9c to the reinforcing plate 9d.
Leading to. The thermal resistance between the die pad 9b and the surrounding reinforcing plate 9d is proportional to the length and cross-sectional area of the bridge 9c. In order to reduce the thermal resistance, it is preferable to make the length of the bridge 9c as short as possible and widen the cross-sectional area. However, the size of the bridge is necessarily determined by the size of the opening 9a. The size of the opening 9a needs to be wide enough not to hinder the bonding of the conductor wire 6 and has a certain limitation. In one embodiment, each bridge is approximately 3 mm long and approximately 0.2 mm thick.
5mm, width 0.7mm in thick area, width 0.2mm in narrow area
Molded in.

In a state where the flexible insulating substrate 3 and the reinforcing plate 9 are adhered and the integrated circuit chip 2 is mounted on the die pad 9b, the electrode pad 2a of the integrated circuit chip and the inner lead 4a of the flexible insulating substrate 3 are , And are electrically connected via the conductor wire 6. The wire bonding is performed with the back side of the semiconductor device 1 facing upward. In the present invention, the lead angle of the conductor wire 6 from the electrode pad 2a is gentler than the lead angle of a conventional semiconductor device. In this embodiment, the integrated circuit chip 2 is located on the side opposite to the surface on which the inner leads are formed with the flexible insulating substrate 3 and the reinforcing plate 9 interposed therebetween, and thus the surface on which the inner leads are formed is formed into an electrode. It can be formed sufficiently away from the pad. If the lead-out angle of the conductor wire is steep, a part of it may come into contact with the corner of the chip. Such a problem causes disconnection of the conductor wire and malfunction of the semiconductor device. The present invention is unlikely to cause such problems with conductor wires. In the present embodiment, as shown in FIG. 3, the conductor wire 6 is pulled out substantially vertically from the electrode pad 2a and is curved above it to reach the inner lead 4a. In one embodiment, the flexible insulating substrate 3
The protruding amount of the conductor wire 6 from the lower surface of the was suppressed to about 0.1 mm.

The conductor wire 6 drawn out from the integrated circuit chip 2 is sealed by potting the resin 11 from above. The resin 11 is potted from the back side of the semiconductor device 1 toward the opening 3 a of the flexible insulating substrate 3. The resin 11 seals the electrode pads 2a, the conductor wires 6, and the inner leads 4a, and protects them from the externally contaminated environment. For the purpose of protection against pollution,
Although it is not always necessary to cover the back surface side of the die pad 9b with a resin, this is a suitable method for facilitating the resin sealing process and increasing the strength of the package. However, if the manufacturing and strength problems are not serious, the die pad 9b
If the potting is performed so as to expose the back surface side of the integrated circuit chip 2, the heat dissipation of the integrated circuit chip 2 is further improved. In one example, the protrusion amount of the resin 11 from the back surface of the flexible insulating substrate 3 was suppressed to about 0.3 mm. Therefore, even if solder bumps having a diameter of about 0.6 to 0.7 mm were used, sufficient clearance was obtained between the external substrate 12 and the surface of the resin 11. The height of the semiconductor device 1 including the solder bumps having a diameter of 0.7 mm could be suppressed to about 0.335 mm. It should be noted that the resin is preferably sealed by a transfer molding method from the viewpoint of mass productivity, and in the present invention, there is no technical problem in sealing the resin by this method.

On the other hand, the back surface side of the integrated circuit chip 2, that is, the front side of the package is exposed without being sealed with resin. In the structure of the present invention in which the integrated circuit chip 2 is mounted toward the reinforcing plate 9, the circuit formed on the main surface of the integrated circuit chip 2 is covered and protected by the die pad 9b of the reinforcing plate 9. The back surface side of the integrated circuit chip 2 protects the circuit formed on the main surface side of the integrated circuit chip 2 as an insulating layer by itself and a physical protection layer against a constant external force, as in the case of the flip chip method. Also works as. Therefore, it is not always necessary to seal the back surface side of the integrated circuit chip 2 with resin. On the contrary, in order to improve the heat dissipation of the integrated circuit chip 2, the structure of the present invention in which one surface of the integrated circuit chip can be exposed is extremely suitable.

Part of the heat generated from the integrated circuit chip 2 is radiated into the air from the exposed back surface side. Other heat is radiated from the die pad 9b on which the integrated circuit chip 2 is mounted to the surrounding reinforcing plate 9d through the bridge 9c. With such a structure of the present invention, efficient heat dissipation of the chip is realized while protecting the integrated circuit chip and the surrounding connection circuits from the external polluted environment.

Next, another heat dissipation structure of the present invention will be described. The solder bumps 5 formed on the lower surface of the flexible insulating substrate 3 originally serve to electrically connect the circuits in the integrated circuit chip 2 to an external substrate, and to supply power and signals to the chip. Is. In the present invention, some solder bumps function to dissipate the heat of the integrated circuit chip 2 onto the external substrate. In the above embodiment, some of the solder bumps 5a at the four corners of the semiconductor device 1 are for heat dissipation. In FIG. 1, these solder bumps 5a are shaded to distinguish them from those for electrical connection.

The solder bumps 5a for heat dissipation are shown in FIGS.
As is clear from the above, the base portion directly contacts the back surface of the reinforcing plate 9. That is, unlike the case of the solder bump 5 for electrical connection, the via 3b is formed on the surface of the flexible insulating substrate 3 at the position of the solder bump 5a at the manufacturing stage, and is bonded to the outer lead 4b at the position of this via 3b. Layer 7 is removed. The solder bumps 5a are formed here. In the example, the solder bumps for supplying the ground potential were brought into contact with the reinforcing plate 9 for heat dissipation. The solder bumps 5a for heat dissipation are provided on the land 13 of the circuit pattern on the external substrate 12 on which the semiconductor device 1 is mounted.
It is soldered like other solder bumps 5. The heat that has reached the peripheral portion 9d of the reinforcing plate 9 from the integrated circuit chip 2 through the bridge 9c is partially dissipated from the surface into the air, and the other portion is the heat-dissipating solder bumps 5a. To the circuit pattern of the external substrate 11.

In the embodiment, the solder bumps located at the four corners of the semiconductor device 1 are used for heat dissipation. In the semiconductor device having the shape shown in this embodiment, the solder bumps near the four corners have the highest probability that the connection with the external substrate side cannot be satisfactorily performed due to the warp or distortion of the package due to the solder reflow or the environmental change. high. Therefore, it is preferable to avoid placing solder bumps for signal connection in this portion as much as possible. Even if some of the heat-dissipating solder bumps are not well connected to the external substrate side, they do not seriously affect the function of the semiconductor device. Therefore, the arrangement of the heat-dissipating solder bumps 5a as in the embodiment is one preferable mode. However, there is no technical problem in disposing the solder bumps for heat dissipation in other positions.

Next, the manufacturing process of the semiconductor device will be described. The flexible insulating substrate is provided in the form of TAB tape. An opening is formed in the center of the flexible insulating substrate, and six vias are formed in each of the four corners corresponding to the positions where the solder bumps for heat dissipation are formed. Punching with a die is suitable for forming the opening and the via. A conductor pattern is formed on one surface of the perforated flexible insulating substrate by film formation and photolithography. The pattern above the via is either not initially formed or is etched away later. Then, a solder resist is applied to the surface of the flexible insulating substrate on which the conductor pattern is formed, exposing the regions of the inner leads.
The solder resist on the outer leads is removed by etching. The copper plate is perforated in another step to form a reinforcing plate. An adhesive is applied to the surface of the flexible insulating substrate opposite to the surface on which the conductor pattern is formed, and the reinforcing plate is adhered onto this. At this time, the reinforcing plate and the flexible insulating substrate are overlapped so that the outer edge of the opening and the outer edge of the opening of the flexible insulating substrate coincide with each other.

The layer of adhesive seen through the vias at the four corners of the flexible insulating substrate is removed by etching. This exposes the back surface of the reinforcing plate in these vias. However, it is also possible to adopt a method in which the part of the adhesive layer to be removed is not formed from the beginning, that is, this part is avoided to form the adhesive layer. In this case, the removal process is omitted. The integrated circuit chip is mounted on the die pad of the reinforcing plate, which is slightly smaller than the integrated circuit chip, with its main surface facing downward. The integrated circuit chip is fixed to the die pad by silver paste or heat conductive adhesive. The semiconductor device is turned over so that the electrode pad and the inner lead can be looked down from above, and wire bonding of both is performed. Then, resin is potted in the opening of the flexible insulating substrate so that the electrode pad, the conductor wire, and the inner lead are completely covered.

Solder bumps are formed at the positions of the outer leads and the vias of the flexible insulating substrate. The solder bumps can be formed by a method of transferring and melting a solder ball that has been prepared in advance, a method of printing cream solder, and a method of reflowing to form bumps. A semiconductor device is mounted on an external substrate by a general method of placing solder bumps on lands on the external substrate and joining them by collective reflow.

FIG. 5 shows a second embodiment of the present invention in which a heat sink is provided on the above semiconductor device. In the figure, the configuration of the semiconductor device 1 is exactly the same as the semiconductor device shown in the previous embodiment. In this embodiment, a heat sink 14 is provided on the semiconductor device 1 in order to more efficiently dissipate heat from the integrated circuit chip. The heat sink 14 is bonded at its center to the back surface of the integrated circuit chip 2 via a heat conductive adhesive, and is also thermally connected to the reinforcing plate 9 via an intermediate member 15. The intermediate member 15 has a height around the semiconductor device 1 which is equal to that of the integrated circuit chip 2.
This is to allow the heat sink 14 having a flat bottom surface to be mounted on the semiconductor device in accordance with the height position. The intermediate member 15 is bonded to the reinforcing plate 9 and the heat sink 14 with a heat conductive adhesive. Intermediate member 1
As polyimide 5, polyimide having a thickness of about 0.1 to 0.3 mm can be used.

6 to 8 show a third embodiment of the present invention. The major difference of the present invention from the previous two embodiments is that the integrated circuit chip 2 is mounted on the die pad 9b from below, that is, from the opening 3a side of the flexible insulating substrate. Therefore, the main surface of the integrated circuit chip 2 faces upward, and the electrode pad 2 passes through the opening 9a of the reinforcing plate 9.
a can look down. Further, unlike the previous embodiment, the conductor pattern 4 is formed on the upper surface side of the flexible insulating substrate 3.
The opening 9a of the reinforcing plate is formed larger than that in the previous embodiment so that the inner lead 4a of the conductor pattern is not covered with the reinforcing plate 9. As a result, the inner lead 4a
Can be exposed through the opening 9a and can be connected to the electrode pad 2a. In the present embodiment, the electrode pads 2a and the inner leads 4a face upward as described above, and wire bonding is performed from the upper surface side of the package. In the previous embodiment, the conductor wire 6 was connected from the electrode pad 2a to the inner lead 4a on the opposite side of the opening 9a of the reinforcing plate. In the present embodiment, the conductor wire 6 extends from the electrode pad 2a, is curved in the opening 9a, returns to the original direction, and is connected to the inner lead 4a. In this example, the electrode pad 2a and the inner lead 4a are at the same height position. Therefore, a sufficient pull-out angle of the conductor wire 6 from the electrode pad 2a can be secured, and there is no contact with the chip. The solder bumps 5 and the outer leads 4b are connected via vias formed in the flexible insulating substrate 3. The structure of this embodiment in which the integrated circuit chip 2 is provided on the same side as the side on which the flexible insulating substrate 3 is provided with respect to the reinforcing plate is an extremely effective structure for making the package thin.

In this embodiment, the resin 11 is potted from above the package to seal the inner lead 4a, the conductor wire 6 and the electrode pad 2a through the opening 9a of the reinforcing plate. Therefore, the back surface side of the integrated circuit chip 2 remains exposed on the bottom surface side of the package. On the surface of the external substrate 12 on which this package is mounted, in addition to the lands 13 for mounting the solder bumps 5, lands 16 of a conductor pattern for mounting the integrated circuit chip 2 are formed. The integrated circuit chip 2 of the present semiconductor device is thermally connected to the land 16 via a heat conductive adhesive 17.
This method of thermally connecting the integrated circuit chip 2 directly to the external substrate side is extremely effective in reducing the thermal resistance of the semiconductor device.

9 and 10 show a fourth embodiment of the present invention. The difference between this embodiment and the first embodiment shown in FIG. 1 is that the central portion of the reinforcing plate 9 is recessed on the mounting surface side of the integrated circuit chip 2. To be more precise, the reinforcing plate 9 is bulged at a position corresponding to the outer side of the inner lead 4a of the flexible insulating substrates 3 that are stacked. The region 3c having the inner leads 4a of the flexible insulating substrate 3 can be bent to the inside of the recess of the reinforcing plate 9 by the notch of the corner, similarly to the flexible insulating substrate 3 shown in FIG. 11 described later. . This region 3c of the flexible insulating substrate 3 is bonded along the recess of the reinforcing plate 9, and the inner lead 4a is located at a position sufficiently retracted from the surface of the flexible insulating substrate 3. By retracting the inner lead 4a, the electrode pad 2a and the inner lead 4
Unlike the case of the embodiment of FIG. 1, the conductor wire 6 connecting a does not protrude from the surface of the flexible insulating substrate 3, that is, the bottom surface of the package. Further, the resin 11 covering the conductor wire 6
The surface of can also be located above the surface of the flexible insulating substrate 3. The structure of this embodiment is important for narrowing the pitch between the solder bumps 5 and increasing the number of mounting pins. If the surface of the resin 11 does not protrude from the surface of the flexible insulating substrate 3 or if the amount of protrusion is small, the package does not contact the external substrate 12 even if the diameter of the solder bump is reduced. By making the solder bumps small, the pitch between the solder bumps can be narrowed.

11 and 12 show a fifth embodiment of the present invention. In this embodiment, a heat sink 18 is used instead of the reinforcing plate in the previous embodiment. Similar to the fourth embodiment, this embodiment has a structure in which the pitch between the solder bumps is narrowed by preventing the resin 11 from projecting to the flexible insulating substrate 3 side. Heat sink 18
On the back surface side of the first recess 18a and the first recess 1
A second recess 18b is further formed in the center of 8a. The region 3c in which the inner lead 4a of the flexible insulating substrate 3 is formed is arranged in the first recess 18a. That is, the region 3c of the flexible insulating substrate 3 has the first recess 18a.
It is arranged along the inclined surface of and is adhered here. Second
The integrated circuit chip 2 is accommodated in the concave portion 18b of and is adhered to the bottom of the concave portion 18b by a heat conductive adhesive 19. The electrode pad 2a of the integrated circuit chip 2 and the inner lead 4a are electrically connected by the conductor wire 6 extending in the first recess 18a. The resin 11 is filled in the recesses 18a and 18b, and covers the conductor wire 6 and its connecting portion.

13 and 14 show a sixth embodiment of the present invention. In this embodiment, the heat sink 18 in the fifth embodiment is made of a thin metal plate. Other configurations are the same as in the fifth embodiment. In order to improve the heat dissipation efficiency of the integrated circuit chip, the fifth embodiment is more preferable than the present embodiment, but the present embodiment is more advantageous in terms of thinning and weight reduction of the package. is there.

[0037]

As described above, according to the present invention, since the integrated circuit chip is mounted with the main surface facing the reinforcing plate, the conductor wire is prevented from protruding above the chip. As a result, the tape BGA package mounting the integrated circuit chip by the wire bonding method can be thinned.

The heat generated from the integrated circuit chip is
The heat resistance of the package can be reduced because it is transmitted through the reinforcing plate and diffused into the air. The low thermal resistance package improves the reliability of the semiconductor device.

Further, conventionally, an integrated circuit chip mounted by wire bonding needs to be covered with resin because its main surface is located above. In the package of the present invention, since the back surface of the chip is located above, it can be exposed. Therefore, the present invention can further enhance the heat dissipation effect in the wire bonding type package.

Further, according to the present invention, the heat transmitted from the integrated circuit chip to the reinforcing plate can be further radiated to the external substrate side by thermally connecting the reinforcing plate and some of the solder bumps, and The reduction of the thermal resistance of is realized.

With the structure of the present invention in which the region of the inner lead of the flexible insulating substrate is set back from the substrate surface, the protrusion of the conductor wire and the resin covering it from the substrate surface can be suppressed. As a result, the pitch between the solder bumps can be narrowed and the mounting pin density can be increased.

With the structure of the present invention in which the integrated circuit chip is fixed to the reinforcing plate surface from the opening side of the flexible insulating substrate, the integrated circuit chip is arranged on the same side as the flexible insulating substrate with respect to the reinforcing plate. . As a result, the package can be made thinner. Further, in this structure, the integrated circuit chip can be directly thermally connected to the external substrate, and the heat dissipation of the chip can be performed more efficiently.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment in which the present invention is applied to a tape BGA package compatible with 256 pins, which is partially cut away and viewed from a bottom surface side.

FIG. 2 is a cross-sectional view showing the semiconductor device of FIG. 1 mounted on an external substrate.

FIG. 3 is an enlarged cross-sectional view showing a main part of FIG.

FIG. 4 is an exploded perspective view showing a main part of the semiconductor device of FIG.

FIG. 5 is a sectional view showing a second embodiment of the present invention including a heat sink.

FIG. 6 is a partially cutaway perspective view showing a third embodiment of the present invention in which an integrated circuit chip is mounted from the flexible insulating substrate side.

FIG. 7 is a perspective view of the semiconductor device of FIG. 6 viewed from the bottom side.

FIG. 8 is a cross-sectional view showing the semiconductor device of FIG. 6 mounted on an external substrate.

FIG. 9 is a perspective view of a fourth embodiment of the present invention, in which the central region of the reinforcing plate is recessed, seen from the bottom side with a part thereof cut away.

FIG. 10 is a cross-sectional view showing the semiconductor device of FIG. 9 mounted on an external substrate.

FIG. 11 is an exploded perspective view of a fifth embodiment of the present invention in which a heat sink is used instead of the reinforcing plate, as seen from the bottom surface side.

FIG. 12 is a cross-sectional view showing the semiconductor device of FIG. 11 mounted on an external substrate.

FIG. 13 is a sixth embodiment of the present invention in which the heat sink is a thin metal plate.
It is sectional drawing which shows the embodiment.

14 is a perspective view of a part of the semiconductor device of FIG. 13 cut away and viewed from the bottom side.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor device 2 Integrated circuit chip 2a Electrode pad 3 Flexible insulating substrate 3a Opening 3b Via 4 Conductor pattern 4a Inner lead 4b Outer lead 5 Solder bump 5a Heat dissipation solder bump 6 Conductor wire 7 Solder resist layer 8 Adhesive layer 9 Reinforcement Plate 9a Opening 9b Die pad 9c Bridge 9d Reinforcing plate peripheral part 10 Silver paste or heat conductive adhesive 11 Resin layer 12 External substrate 13 Circuit pattern 14 Heat sink 15 Intermediate member 16 Land 17 Adhesive layer 18 Heat sink 18a First recess 18b Second Recesses 19 Adhesive layer

Claims (10)

[Claims] 1. A flexible insulating substrate having a conductor pattern formed on a surface thereof and opening at least a part of a mounting position of an integrated circuit chip; and a conductive pattern electrically connected to the conductor pattern provided on one surface side of the flexible insulating substrate. A plurality of solder bumps to be connected to, a reinforcing plate provided on the surface of the flexible insulating substrate opposite to the surface on which the solder bumps are provided, and a surface provided with an electrode pad on the reinforcing plate side. An integrated circuit chip mounted on the surface of the reinforcing plate, an opening formed at a position corresponding to the electrode pad of the reinforcing plate for spatially communicating the electrode pad and the inner lead of the conductor pattern, and the opening And a conductor wire for electrically connecting the electrode pad and the inner lead of the conductor pattern, and a resin for sealing at least the conductor wire. 2. A region of the reinforcing plate on which the integrated circuit chip is mounted and its periphery are recessed to the side opposite to the side of the flexible insulating substrate, and a region where the inner lead of the flexible insulating substrate is formed. 2. The semiconductor device according to claim 1, wherein is positioned closer to the reinforcing plate than the surface of the flexible insulating substrate. 3. The semiconductor device according to claim 1, further comprising a heat sink provided on the integrated circuit chip and the reinforcing plate. 4. The semiconductor device according to claim 1, wherein the integrated circuit chip is fixed to the reinforcing plate surface from an opening side formed in the flexible insulating substrate. 5. The semiconductor device according to claim 4, wherein the integrated circuit chip is thermally connected to a conductor pattern formed on a substrate on which the semiconductor device is mounted. 6. The reinforcing plate and a part of the plurality of solder bumps are thermally connected to each other.
13. The semiconductor device according to claim 1. 7. A flexible insulating substrate having a conductor pattern formed on a surface thereof and opening at least a part of a mounting position of an integrated circuit chip, and the conductor pattern provided on one surface side of the flexible insulating substrate and electrically connected to the conductor pattern. A plurality of solder bumps connected to the flexible insulating substrate, a heat sink provided on the surface of the flexible insulating substrate opposite to the surface on which the solder bumps are provided, the integrated circuit chip, and the flexible insulating substrate. The region where the inner lead is formed in the conductor pattern is located closer to the heat sink than the surface of the flexible insulating substrate, and the surface provided with the electrode pad is the recess formed in the heat sink. An integrated circuit chip mounted in the recess, a conductor wire for electrically connecting the electrode pad and the inner lead of the conductor pattern, and the recess. A semiconductor device comprising: a resin that is filled in and encapsulates the integrated circuit chip and the conductor wire. 8. The first recess is formed in the center of the first recess for accommodating the region where the inner lead is formed of the flexible insulating substrate, and the first recess is for accommodating the integrated circuit chip. The semiconductor device according to claim 7, further comprising two recesses. 9. The semiconductor device according to claim 7, wherein the heat sink is a thin metal plate. 10. The heat sink and a part of the plurality of solder bumps are thermally connected to each other.
13. The semiconductor device according to claim 1.