JPH10112519A - Integrated circuit device with heat dissipation means and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an integrated circuit device which fits to a small IC packet and whose heat dissipation characteristic is satisfactory and to provide its manufacture method. SOLUTION: The device contains a chip 1 where an integrated circuit is formed, and leads 2a and 2b connected to the terminal and a mounting face is decided by the bending direction of the leads. A die pad 20 where the chip is provided on the surface, a heat radiating body 4 connected to the back of the die pad 20 and a sealing body 5 sealing the chip 1, the die pad 20, the leads, and the heat radiation body are provided on the integrated circuit device. The heat radiation body 4 is exposed on a side opposite to a mounting face-side. In the manufacturing method of the device, a fixing process for fixing a heat radiation member on the back of the die pad 20 in a lead frame is provided, and at least either process in a die bonding process of loading and fixing the chip 1 on the surface of the die pad 20 or a wire bonding process for connecting the terminal of the chip and the inner leads in the lead frame by bonding wire, is executed after the fixing process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device and / or a semiconductor device.
Or integrated circuit (IC) formed by other elements
In particular, the present invention relates to an integrated circuit device having heat dissipation means and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, heat dissipation of a power IC, which consumes a large amount of power, has been particularly important. But today,
Regardless of the level of power consumption, the heat generation density (concentration) of the small IC (LSI) package used for the electronic device itself is steadily increasing as the performance of the electronic device itself is increased and the size and weight of the electronic device are reduced. I have. Therefore, heat dissipation technology in such an IC package is an important issue.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide an integrated circuit device which is suitable for a small-sized IC package and has good heat radiation characteristics, and an apparatus therefor. It is to provide a manufacturing method.

[0004]

SUMMARY OF THE INVENTION An integrated circuit device according to the present invention includes an IC chip on which an integrated circuit is formed and a lead connected to a terminal of the IC chip. A fixed integrated circuit device, comprising: a die pad having the IC chip disposed on a front surface thereof; a radiator coupled to a back surface of the die pad; and a seal for sealing the IC chip, the die pad, the lead, and the radiator. And a stop body, wherein the heat radiator is exposed on a side opposite to the mounting surface side.

[0005] A method of manufacturing an integrated circuit device according to the present invention comprises:
A method of manufacturing an integrated circuit device, wherein a mounting surface is determined by a bending direction of the lead, including an IC chip on which an integrated circuit is formed, and a lead connected to a terminal of the IC chip, the method comprising: A fixing step of fixing the heat radiating member to the back surface, after this fixing step, a die bonding step of mounting and fixing the IC chip on the surface of the die pad, and a terminal of the IC chip and an inner in the lead frame. The method is characterized in that at least one of wire bonding processes for connecting leads to bonding wires is performed.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of an integrated circuit device according to one embodiment of the present invention. FIGS. 2 and 3 show plan views of a form of a lead frame and a heat dissipating member (heat spreader) used in the integrated circuit device, which will be appropriately referred to in the following description.

In FIG. 1, an IC chip 1 on which a semiconductor integrated circuit is formed is connected to a die pad 20 of a lead frame 2.
More specifically, it is bonded to the die pad 20 by forming, for example, a eutectic alloy at a joint portion between the two or by applying a silver paste. Chip 1
Has an actual integrated circuit formed on the substrate, the layer on which the integrated circuit is formed is disposed on the bottom side of the package, and the substrate is bonded to the die pad 20. This form is also called a die down and is one of the features of the present embodiment. Of chip 1,
The surface of the integrated circuit forming layer (the lower surface in FIG. 1) is coated with a surface protective film such as a PSG (phosphor glass) film (not shown). A plurality of pads are exposed.

[0008] The bonding pads 3 are connected between the chip pads and the tips of the inner leads 2 a of the lead frame 2. The inner lead 2a is
Outer lead 2b corresponding to each pad of chip 1 and extending individually to the outer edge of the package and serving as an external terminal
(See FIG. 2). The heat dissipating member 4 is formed on the back surface of the die pad 20, that is, on the surface opposite to the fixing surface of the chip 1. The heat dissipating member 4 has a sufficient main surface area to cover the main surface of the die pad 20 with a margin (FIG. 3).
Reference), and fixed to the back surface of the die pad 20 via a predetermined adhesive or by performing a predetermined fixing process. As can be seen from FIG. 3, the heat radiating member 4 has a generally disk-shaped outer shape, and more specifically, has a flat bottom portion 40 and its outer periphery is surrounded by a relatively thin wall portion 41. ,
A large number of cylindrical bodies 42 carrying the heat radiation fins and having the same height are arranged and erected in the surrounded area.
The cylindrical body 42 'arranged at the center of the main surface of the heat radiating member 4 has a larger surface area than other cylindrical bodies. This is for facilitating the transportation of the heat radiating member 4 using the large surface portion by a vacuum device or the like in an assembling process described later. Furthermore, since the shape of the heat dissipating member 4 is disk-shaped as described above, there is also an advantage that, when the heat dissipating member 4 is attached to the lead frame 2, positioning can be performed only by using the center position of the circle as a reference.

The heat radiating member 4 is desirably formed integrally, and is preferably made of a material having good heat radiating properties (high heat conductivity). As an example, a heat dissipating member having such a structure can be easily realized by casting using a copper-based or iron-based material as in the case of aluminum die casting. The chip 1, die pad 20, inner lead 2a, bonding wire 3, and heat radiating member 4 are collectively sealed with, for example, a predetermined resin.
The sealing body 5 is formed. However, the sealing body 5 is a heat radiation member 4
Instead of embedding the whole, the sealing is performed in such a manner that the side on which the cylindrical bodies 42, 42 'are formed is exposed.

The envelope of the heat radiating member 4 in the height direction (vertical direction in FIG. 1) is aligned with the top surface of the sealing body 5. The external conformity between the heat radiating member 4 and the sealing body 5 is also one of the features of the present embodiment. In other words, the heat dissipating member 4 has the same height as the conventional small package without protruding from the shape enclosing the top surface of the sealing body 5, which is extremely advantageous for miniaturizing the entire package in the height direction. is there. This is equivalent to the fact that the conventional external heat spreader is significantly downsized in the height direction as compared with the case where the external heat spreader is erected on the package of the finished product. In addition, miniaturization of the mounting substrate in the vertical direction is promoted at the same time.

In addition, since the heat dissipating member 4 has a large number of fins and a large external surface area in spite of being sealed with a resin, it is possible to secure heat radiation substantially equal to that of a conventional external heat spreader. Is possible. It is also important that the heat radiating member 4 be in direct contact with the die pad 20, have a larger main surface area than the die pad 20, and be configured to be exposed upward in the package. With such a configuration, the efficiency of dissipating heat generated by the chip 1 is improved. In the package, the radiating member faces downward, that is, is exposed to the mounting surface side.The radiating member contacts or approaches the surface of the printed circuit board after mounting, and the radiating member is not exposed to the outside air. The result is that it cannot be used to its full potential. This embodiment leads to the opposite result.

Further, there is a great merit in that the heat radiation member 4 is provided on the back surface of the die pad 20. When a heat radiation member is provided on the integrated circuit formation layer side of the chip 1 (the lower side in FIG. 1), the substantial contact area with the chip 1 is limited due to the restriction of the bonding wire connected to the electrode pad of the formation layer. A small heat radiating member must be adopted. In this case, a step of attaching the heat radiating member after wire bonding is performed from the manufacturing point of view, and at the time of attaching the heat radiating member, the contact between the bonding wires (so-called short-circuit) is constantly caused.
And deformation of the inner leads must be taken into account. However, in the present embodiment, the heat radiating member 4 is provided on the back surface side of the die pad 20 where the bonding wire 3 is not provided, so that a substantial contact area with the chip 1 can be increased, and before the wire bonding, The heat radiating member 4 can be attached to the lead frame 2 in advance, and the heat radiating member 4 can be incorporated without much concern about contact between bonding wires and deformation of the inner lead.

Next, a method of manufacturing the integrated circuit device will be described. First, reference is made to FIG. 4 to clarify the overall manufacturing flow. FIG. 4 is a flowchart mainly showing a so-called assembly process, in which dicing (step S1) is performed to divide chips formed on a wafer into individual chips.
0) is performed. On the other hand, the lead frame 2 is introduced into the manufacturing apparatus in parallel with the dicing step (step S).
01), the heat radiation member 4 is mounted. The lead frame 2 is, as shown in FIG.
e are provided at the four corners, and a multiple frame form in which lead frames of the same pattern are continuously connected is adopted. In the introduction step S01, the sprocket of the manufacturing apparatus is inserted through the guide hole 2e to position the lead frame 2 at a predetermined position while moving forward. In the heat radiation member fixing step S02, first,
The back surface of the die pad 20 with respect to the positioned lead frame 2 (the surface opposite to the side on which the chip 1 is mounted)
Then, an adhesive having a high thermal conductivity such as a so-called epoxy adhesive is applied. Then, the above-mentioned heat radiating member 4 is fixed to the back surface of the die pad 20 via this adhesive. As a means for such adhesion, a double-sided adhesive tape made of a substance having high thermal conductivity can also be employed.

The lead frame 2 to which the heat radiating member 4 is fixed is subjected to die bonding (step S11) in the next stage. This is achieved by mounting and fixing the single chip 1 obtained in the step S10 on the die pad 20, which is opposite to the fixing surface of the heat radiating member 4, via a silver paste. Lead frame 2
As can be seen from FIG. 2 showing an example of the embodiment, the square die pad 20 is arranged at the center of the lead frame 2 and is provided outside the lead frame by suspending pins (or die pad support patterns) 2c extending in the respective diagonal directions. Frame 21
Is linked to Near the peripheral edge of the die pad 20, the tips of the lead pads 2a are arranged along the edge. The inner lead 2a is connected to the outer lead 2b through a resin flow stopping pattern 2d called a dam bar or a tie bar.

After the die bonding in step S11, the die-bonded lead frame 2 is placed in an atmosphere of, for example, 150 to 190 ° C. for a few hours to solidify a silver paste as a thermosetting resin on the die pad. Cure (step S12) is performed. Next, wire bonding (step S13) for individually connecting the pads of the chip 1 fixed to the die pad 20 and the corresponding tips of the inner leads 2a is performed. Here, the form of the lead frame 2 at the time of wire bonding is shown in FIG. FIG. 5 corresponds to a sectional view taken along line AA in FIG. As shown in this figure, unlike FIG. 1, the heat radiating member 4 is arranged downward and wire bonding is performed.

When all the bonding to the inner lead 2a is completed, the process proceeds to a resin sealing step S14. In the sealing step S14, the sealing body 5 described above is formed. The details will be described later. Resin sealing step S1
When the step 4 is completed, the cured lead frame 2 is placed in an atmosphere of, for example, 150 to 190 ° C. for 5 to 7 hours in order to harden the thermosetting resin forming the sealing body 5. Step S15) The processing is performed. afterwards,
The dam bar 2d is cut (step S16), the outer leads 2b are plated (step S17), and lead shaping is performed (step S18).

In the lead shaping step S18, the outer lead 2b is processed into a gull-wing shape having two bending points as shown in FIG. Note that, as described above, since the present integrated circuit device adopts a die-down configuration, the outer leads 2b are formed on the integrated circuit forming layer side of the chip 1, that is, on the chip pad forming surface side from the first package body. A bend is made. In other words, the outer lead 2b is formed in a gull wing shape so that the heat radiation member 4 is mounted with the heat radiation member 4 facing upward. Step S1
At 8, unnecessary parts such as the unsealed exposed portions of the suspension pins 2 c are removed, and the sealing body 5 and the portion sealed by the sealing body 5 are separated from the lead frame 2.

When the integrated circuit device as shown in FIG. 1 is thus obtained, it is transported through inspection (step S19), packing (step S20), and shipment (step S21). Next, the mode of the resin sealing step S14 will be described in detail. FIG. 6 shows a transfer mold for packaging (resin sealing) of the present integrated circuit device by a so-called low-pressure transfer molding method, a manufacturing apparatus including the same, and a bonded chip 1 set in the manufacturing apparatus. FIG. 3 is a schematic cross-sectional view showing a lead frame 2 mounted and to which a heat radiation member 4 is fixed. Note that the lead frame 2 in FIG. 6 corresponds to the BB cross section in FIG. 2, but is illustrated more simply.

In FIG. 6, a manufacturing section for molding the resin sealing body 5 mainly includes an upper mold (upper mold) 61 and a lower mold (lower mold) 71 serving as mating molds. An injection mechanism for injecting the liquid resin into the cavities 610 and 710 by a mold, and a void removing mechanism for removing bubbles or voids from the injected resin in the cavity. Such an injection mechanism includes a cull hole 8.
1, the transfer plunger 91, the runner R1, and the gate G1, and the void removing mechanism is composed of an air vent V1.

The upper mold 61 and the lower mold 71 are heated to a predetermined temperature in advance, and sandwich the lead frame 2 to be sealed fixed at a predetermined position (clamping). On the other hand, a predetermined resin 50 previously formed into a tablet shape as a raw material of the sealing body 5 is subjected to high frequency heating, and is filled in the cull hole 81. Alternatively, a raw material (tablet) is put into a cull hole of a mold that has been heated to a predetermined temperature in advance, preheated and filled. And then
The transfer plunger 91 is operated to squeeze the raw material resin 50, and the cavity 6 is formed through the runner R1 and the gate G1.
The melt pressure is injected into 10,710.

At this time, the positional relationship between the upper die 61 and the lead frame 2 is fixed such that the die pad 20 is located at the center of the cavity 610. As shown in FIG. 2, a dashed line for indicating the position of the sealing body 5 in FIG. 2 indicates this relationship. Further, since the exposed end surface of the heat radiating member 4 and the bottom surface of the concave portion of the lower mold 71 are in close contact with each other, the liquid resin does not enter the groove between the cylindrical fins 42 and 42 'in the heat radiating member 4.

In each cavity at the beginning of resin injection,
Voids are mixed in the injected resin. The air vent V1 is a groove for extruding or extracting the void to the outside, and eliminates a final mixed void in the sealing resin. The gate G1 and the vent V1 may be formed in a lower mold. As can be seen from the above description, according to the present manufacturing method, the lead frame 2
The heat dissipating member 4 is attached to the substrate, and then die bonding and wire bonding are performed. By ensuring this procedure, it is possible to avoid the contact between the bonding wires and the deformation of the inner lead as described above, thereby realizing an integrated circuit device having heat radiation means with easy workability. it can.

Except for manufacturing the heat radiating member 4, a conventional method of manufacturing a resin-sealed integrated circuit device can be applied, so that the existing assembly equipment and system can be shared. It is easy and easy to prepare an assembly facility for the present integrated circuit device without much expense. Thus, the present integrated circuit device can be manufactured while maintaining low cost in terms of manufacturing.

As a modification of the above embodiment, a structure as shown in FIG. 7 is preferable. In FIG. 7, a required portion of the heat radiation member 4 is chamfered. Therefore, the roundness 4A is provided at each of the locations, and the sealing body 5 is formed so as to cover the roundness 4A, so that stress concentration on the heat radiation member in the package can be prevented. This makes it possible to realize an integrated circuit device having not only good heat dissipation but also good crack resistance.

In the above embodiment, the heat radiating member 4 as shown in FIGS. 1 and 3 is employed. However, the present invention is not limited to such a shape and structure but can be modified into various forms. It is. For example, the cylindrical body that carries the radiation fin is shown in FIG.
Although they are arranged in a lattice shape, they may be arranged in a staggered manner, and various arrangement forms can be adopted. The radiating fins may not be in the shape of a cylinder, but may be in the shape of a prism, a hemisphere or a protrusion.

Although the die bonding and the wire bonding are performed after attaching the heat radiating member 4 to the lead frame 2, the heat radiating member 4 may be attached after at least one of the die bonding and the wire bonding is completed. The point is that the heat radiating member 4 can be provided without being restricted by these bondings.
The present invention has great advantages.

Further, in the above-described embodiment, the QFP type package has been described. However, the present invention is not limited to this, and the present invention can be applied to various types such as a DIP type. It does not matter. In addition, various structures, means, and steps have been specifically or simply described in the above-described embodiment, but can be appropriately modified within a range that can be designed by those skilled in the art.

[0028]

As described in detail above, according to the present invention,
An integrated circuit device suitable for a small-sized IC package and having good heat radiation characteristics and a method for manufacturing the same can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an integrated circuit device according to an embodiment of the present invention.

FIG. 2 is a view showing one embodiment of a lead frame applied to the integrated circuit device of FIG. 1;

FIG. 3 is a plan view of a heat dissipation member applied to the integrated circuit device of FIG. 1;

FIG. 4 is a flowchart showing a method of manufacturing an integrated circuit device according to one embodiment of the present invention.

FIG. 5 is a sectional view showing a form of a lead frame in a wire bonding step in the manufacturing method of FIG. 4;

FIG. 6 is a schematic cross-sectional view showing a transfer mold for packaging the integrated circuit device of the present embodiment by a low-pressure transfer molding method, a manufacturing apparatus including the same, and a lead frame 2 set in the manufacturing apparatus. FIG.

FIG. 7 is a sectional view showing a modified example of the integrated circuit device of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 IC chip 2 Lead frame 20 Die pad 21 Outer frame 2a Lead pad 2b Inner lead 2c Hanging pin 2d Dam bar 2e Guide hole 3 Bonding wire 4 Heat radiating member 40 Bottom 41 Wall 42,42 'Cylindrical body 4A Roundness 5 Sealing body 61 Mold 610 Upper mold cavity 71 Lower mold 710 Lower mold cavity 81 Cull part 91 Plunger R1 Runner G1 Gate V1 Air vent 50 Resin tablet

Claims (12)

[Claims] 1. An integrated circuit device, comprising: an IC chip on which an integrated circuit is formed; and a lead connected to a terminal of the IC chip, wherein a mounting surface is determined by a bending direction of the lead. A die pad on which the IC chip is disposed; a radiator coupled to a back surface of the die pad; and a sealing member for sealing the IC chip, the die pad, the lead, and the radiator. An integrated circuit device which is exposed on a side opposite to the mounting surface side. 2. A height of an end face of an exposed portion of the heat radiator is:
2. The integrated circuit device according to claim 1, wherein a height of the sealing body is substantially equal to a height of a top surface of the sealing body. 3. The integrated circuit device according to claim 1, wherein the radiator has a radiation fin in an exposed portion. 4. The integrated circuit device according to claim 3, wherein the radiator has a disk shape in a portion other than the radiator fin, and the radiator fin is formed in a columnar shape. 5. The integrated circuit according to claim 1, wherein an area of a surface of the heat sink connected to the die pad is larger than a main surface area of the die pad. apparatus. 6. The die pad and the lead are obtained from a lead frame, the terminal of the IC chip and the lead are connected by wire bonding on the mounting surface side, and the external lead of the lead is ,
The integrated circuit device according to any one of claims 1 to 5, wherein the first bend is provided on the mounting surface side. 7. The integrated circuit device according to claim 1, wherein the heat radiator is chamfered on a side in contact with the sealing body. 8. A method for manufacturing an integrated circuit device, comprising: an IC chip on which an integrated circuit is formed; and a lead connected to a terminal of the IC chip, wherein a mounting surface is determined by a bending direction of the lead. A fixing step of fixing a heat radiating member to the back surface of the die pad in the lead frame; after this fixing step, a die bonding step of mounting and fixing the IC chip on the surface of the die pad; A method for manufacturing an integrated circuit device, comprising performing at least one of a wire bonding step of connecting an inner lead of the lead frame with an inner lead by a bonding wire. 9. A sealing step of forming a sealing body for sealing the IC chip, the die pad, the inner lead, and the heat radiating member, and an external lead of the lead frame on a side opposite to a side on which the heat radiating member is arranged. The method of manufacturing an integrated circuit device according to claim 8, further comprising: a lead shaping step of shaping the external lead so that the external lead can be mounted. 10. The sealing step includes performing transfer molding using first and second molds for holding the lead frame that has been subjected to the wire bonding step. 10. The method of manufacturing an integrated circuit device according to claim 8, wherein one of the second molds has a cavity recess including a bottom surface in close contact with an end surface of the exposed portion of the heat radiating member. 11. The heat radiator has an exposed surface at a predetermined position so that the heat radiator is easily conveyed and is easily processed to be fixed to the back surface of the die pad. 11. The method for manufacturing an integrated circuit device according to 9 or 10. 12. The radiator according to claim 12, wherein the exposed surface carries a radiator fin having a main surface area larger than other radiator fins, and the predetermined position is a center position on the main surface of the radiator. Item 12. The method for manufacturing an integrated circuit device according to item 11.