JPH07307421A - Lsi chip and its packaging structure - Google Patents

Abstract

PURPOSE:To obtain a packaging structure of an LSI chip allowing mounting without reducing a wiring region of an LSI loading part while being low-priced and facilitating connection check. CONSTITUTION:In addition to a pad for usual electric connection provided on the surface, an LSI chip 1a provided with a pad for radiation on the inside part of this pad for electric connection is loaded on a base substrate 5 with phase-up and a pad 7 for electric connection of the peripheral part is connected to the base substrate 5 by connection of a wire 8 and a pad 2 for heat radiation in the inside is connected to a heat sink 4 by using a solder bump 3, and this heat sink 4 and a heat-radiation fin 10 are joined thermally and mechanically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LSI (Large Scale Integrated Circuit) chip and its packaging structure, and more particularly to a radiator (heat
LSI suitable for packaging with spreader)
The present invention relates to a chip and its packaging structure.

[0002]

2. Description of the Related Art With the increase in power consumption of semiconductor devices, low thermal resistance is indispensable even in inexpensive plastic packages. As a text of such technology, VLS
I packaging technology (bottom): Nikkei BP, 1993
Published May 31, 2012, p. 200-p. 209, which is described as a low thermal resistance package structure. As the low thermal resistance package structure of the plastic package, as described in the above document,
There are three possibilities: (1) high thermal conductivity of material, (2) design change of lead frame, and (3) built-in heat sink. Of these, the one related to the present invention is (3) the built-in structure of the heat radiator, that is, the packaging structure of the LSI chip employing this heat radiator.

FIG. 5, FIG. 6 and FIG. 7 show conventional high heat dissipation LS.
It is a cross-sectional schematic diagram which shows three different structures of an I packaging structure, respectively. For each figure, heat dissipation type LS
The characteristic points of the I packaging structure will be briefly described.
First, the structure of FIG. 5 shows the most typical structure. The LSI chip 1 is mounted on the base substrate 5, and the LSI chip 1 is connected by the lead terminals 11 taken out from the base substrate 5 and the wires 8 connected to the lead terminals 11. Is connected to an electrical connection pad (not shown) provided in the. This configuration is LSI
This is a very general method for connecting the chip 1 to the base substrate 5 which is inexpensive and low cost. And the base substrate 5
On the surface opposite to the mounting surface of the LSI chip 1,
0 is attached, and the end portions of the lead terminals 11 are soldered to the mother board 12 to be mounted entirely or mounted. The portion of the LSI chip 1 including the wires 8 is covered with the resin coat 9 and packaged.

Further, the structure shown in FIG. 6 is an arrangement especially for a high heat generation type LSI chip 1, and a cavity 18 is provided at the center of the base substrate 5 to expose the surface of the heat radiation fin 10 at this portion. The LSI chip 1 is directly mounted on the radiating fin 10 at the center thereof. In this case, since there is a gap between the inner wall of the cavity 18 and the outside of the LSI chip 1, it is possible to prevent the base substrate 5 from being burnt out, and the LSI chip 1 directly contacts the heat radiation fin 10, so that the heat radiation performance is significantly improved. Is excellent.

Further, the structure of FIG. 7 is different from the structure of FIG. 5 in that a heat dissipation via 13 is provided in the mounting region of the LSI chip 1 in the thickness direction of the base substrate 5. LS that generates heat
The heat of the I-chip 1 is radiated through the radiating vias 13 to radiate the fins 1.
Since it conducts to 0, it can be said that the structure achieves relatively efficient heat dissipation. The packaging structure shown in FIGS. 5 to 7 is of a face-up mounting type in which the mounting surface of the electrical connection pads of the LSI chip 1 (actually the active element surface of the chip) is connected upward. Met.

Next, in contrast to the face-up mounting method just described, as a face-down mounting method having a structure in which the active element surface of the chip is connected downward,
Although not of the resin coat type as shown in FIGS. 5 to 7, there are those shown in the schematic configuration diagrams of FIGS. 8 and 9. First, in the structure shown in FIG. 8, the LSI mounting portion on the base substrate 5 is used as a wiring area, and the TAB 16 is used to connect the LSI chip 1 and the lead terminal 11. Lead terminal 1
1 is taken out from the surface of the base substrate 5 on the side opposite to the TAB mounting surface and soldered to the mother board 12. A cushioning material 15 is provided between the LSI chip 1 and the base substrate 5.
Is inserted, and the main body portion mainly including the LSI chip 1 is shielded on the LSI chip 1 via the heat conductive material 14 by the cap 17 having good thermal conductivity. The heat radiation fin 10 is connected to the cap 17.

The configuration of FIG. 9 is the same as the TAB of FIG.
The solder bumps 3 are used instead of 16 for electrical connection. In this case, a structure is used in which a buffer material 15 having good thermal conductivity is used instead of the thermal conductive material 14 of FIG.

[0008]

In the conventional high heat dissipation LSI mounting method as described above, heat is dissipated by the wiring connection between the base substrate and the LSI chip via the wire as shown in the conventional example of FIG. Is common. Although this method is the cheapest method, it has a drawback that it cannot fully cover high heat-generating LSI chips. In addition, since the cavity (FIG. 6) or the heat dissipation via (FIG. 7) is provided in the base substrate portion on which the LSI chip is mounted, this portion cannot be used as an area for wiring. There was a problem of increasing the number of layers. As a solution to this problem, the method of using the LSI mounting portion of the substrate as a wiring area is the conventional face-down mounting method shown in FIGS. 8 and 9. In this face-down mounting method, TAB is used. Since it is used (FIG. 8), there is a problem that the cost becomes high, and since the solder bumps (FIG. 9) make all the electrical connections, the connection check after the connection is impossible.

The present invention has been made to solve the above-described problems, and enables face-up mounting without reducing the wiring area of the LSI mounting portion, and enables wire connection by a general connection method. It is an object of the present invention to provide an LSI chip and its packaging structure that are low in cost and easy to check the electrical connection.

[0010]

In the LSI chip according to the present invention, in addition to a normal electrical connection pad provided on the surface, a heat dissipation pad is provided inside the electrical connection pad. It is a thing.

Further, in the packaging structure of the LSI chip according to the present invention, the above-mentioned LSI chip according to the present invention is mounted face up on the base substrate, and the electrical connection pads in the peripheral portion are connected to the base substrate by wire connection. The heat dissipation pad on the inner side is connected to the heat sink using a solder bump or a wire having a low heat resistance, and the heat sink and the heat dissipation fin are thermally and mechanically coupled.

[0012]

According to the present invention, the LSI chip has, in addition to the usual electrical connection pads in the peripheral portion, heat dissipation pads formed in a larger area than the electrical connection pads in the inner portions thereof. If the thermal circuit is formed by the connection through the heat dissipation pad, it can be used as the main heat dissipation circuit of the high heat generation type LSI chip.

Further, if the LSI chip according to the present invention is used and its heat dissipation pad having a relatively large area is used, it is possible to make a thermal connection to a heat sink via a solder bump, or to use a wire having a low thermal resistance (for example, a relatively low heat resistance). By performing a thermal connection by a wire bonding method using a thick wire, an LSI packaging structure having a high heat dissipation function can be obtained.

[0014]

【Example】

[Embodiment 1] FIG. 1 is a schematic sectional view showing an embodiment of an LSI chip according to the present invention. In FIG. 1, the LSI
An electrical connection pad 7 similar to that of the conventional product is arranged in the peripheral portion of the active element surface of the chip 1a. The inner surface of the electrical connection pad 7 is a functional element. There is provided at least one (actually, a plurality of) heat radiation pads 2 made of, for example, a metal film that is not related to the above. The Joule heat generated by the operation of the LSI chip 1a after mounting is also radiated by the electrical connection pad 7 via the wire bonding wire as described above, but it is mainly discharged through the heat radiation pad 2. Is possible.

[Second Embodiment] FIG. 2 shows an LS according to the present invention.
It is a schematic cross section which shows the 1st Example of the packaging structure of I chip. In FIG. 2, the solder bumps 3 are formed on the heat dissipation pads 2 of the LSI chip 1a,
a and the heat sink 4 are flip-chip mounted (generally, the active element surface of the chip is directed to the substrate and the chip is directly connected to the substrate by bumps or the like, but in the case of FIG.
The board here corresponds to the heat sink). And the LSI chip 1 with the heat sink 4
After a is adhered to the base substrate 5, the base substrate side connection pad 6 and the electrical connection pad 7 are connected by the wire 8 by the wire bonding method. After fixing the LSI mounting portion with the resin coat 9, the radiation fins 10 are attached and the packaging is completed. In the case of an intermediate module such as a multi-chip module, the lead terminal 11 is connected to the mother board 12. According to this embodiment, the heat generated from the LSI chip 1a is radiated from the heat radiating fins 10 through the heat sink 4, so that the wiring in the substrate can be effectively performed as before and the cost can be increased without increasing the cost. The connection check after automatic connection can be easily performed.

[Third Embodiment] FIG. 3 shows an LS according to the present invention.
It is a schematic cross section which shows the 2nd Example of the packaging structure of I chip. In the case of FIG. 3, the configuration in which the LSI chip 1a and the heat sink 4 are connected by the flip chip mounting method is the same as that of the second embodiment. In this case, in particular, the heat sink 4 is formed of an insulating material (for example, boron nitride, aluminum nitride, or the like) having good heat conductivity and capable of wiring, such as ceramic, and further, the pattern 19 is formed on the heat sink 4 and the component 20 is formed. Is being installed. When the heat sink 4 is mounted, not only the heat dissipation pad 2 of the LSI chip 1a but also the heat dissipation pattern (reference numeral omitted) in the pattern 19 and the predetermined electrical connection pad 7 on the LSI chip 1a are connected by the solder bumps 3. Connecting. Finally, the heat radiation fin 10 is adhered onto the heat sink 4, and the whole is capped and connected to the base substrate 5 via the heat radiation fin 10 to complete the assembly. In the structure of this embodiment, the wiring pattern 19 of the heat sink 4 can accommodate a terminating resistor for high-speed signals, a decoupling capacitor (decoupling capacitor), etc. as the component 20, and these terminating resistors are provided in the vicinity of the LSI chip. Since a decoupling capacitor, etc. can be placed, the high-frequency characteristics of the LSI package, that is, the characteristics that contribute to speeding up, which may be called high-speed characteristics, can be significantly improved, and a high-density mounting can be achieved. There is.

[Fourth Embodiment] FIG. 4 shows an LS according to the present invention.
It is a schematic cross section which shows the 3rd Example of the packaging structure of I chip. The basic configuration of this embodiment is similar to the wire bonding method, but is characterized in that it can be achieved by using the embodiment chip of FIG. That is, in FIG. 4, the heat sink 4 as a heat conduction path attached to the peripheral portion of the LSI is connected to the heat radiation pad 2 by the heat radiation wire 8a, and then the heat radiation fin 10 integrated with the case is used as the heat sink. It is the one that was crowned with 4. It should be noted that it is preferable that the wire 8a has a low thermal resistance by using a wire slightly thicker than the normal wire 8, and it can be said that it is an advantage that a thick wire can be used in this configuration. The effect added to the structure of this embodiment in addition to the improvement of the thermal conductivity is that the intermediate inspection is further facilitated because all the connections are made by wires.

[0018]

As described above, according to the present invention, the LSI
It is assumed that the chip has a heat dissipation pad in addition to an electrical connection pad with the outside, and the LSI chip is used to be mounted on a base substrate by connection, and the heat dissipation pad and the heat sink of the LSI chip are low thermal resistance members. Since the heatsink and the heat radiation fin are in thermal contact with each other via a heatsink, even if the LSI chip is mounted face-up, a conventional cavity or heat radiation via is provided on the mounting board for high heat radiation. As in the case of achieving the above, it is possible to achieve low-cost high heat dissipation packaging of an LSI chip without increasing the substrate size or the number of substrate layers in order to secure the wiring area of the substrate. Further, in the case of the method of wire-bonding the heat dissipation pad of the LSI chip and the heat sink with the low thermal resistance wire, there is an advantage that the connection check of the electrical connection in the intermediate inspection can be easily performed. Further, since it is possible to attach passive elements to the heat sink housed inside, in this case, the original purpose of the present invention, that is, element characteristics other than high heat dissipation effect, such as improvement of high frequency characteristics by a packaging method, can be achieved. An important effect can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of an LSI chip according to the present invention.

FIG. 2 is a schematic sectional view showing a first embodiment of the packaging structure according to the present invention.

FIG. 3 is a schematic sectional view showing a second embodiment of the packaging structure according to the present invention.

FIG. 4 is a schematic sectional view showing a third embodiment of the packaging structure according to the present invention.

FIG. 5 is a schematic sectional view showing a configuration of a conventional high heat dissipation LSI packaging structure.

FIG. 6 is a schematic sectional view showing a configuration of a conventional high heat dissipation LSI packaging structure.

FIG. 7 is a schematic sectional view showing a configuration of a conventional high heat dissipation LSI packaging structure.

FIG. 8 is a schematic configuration diagram of a conventional face-down mounting type packaging structure.

FIG. 9 is a schematic configuration diagram of a conventional face-down mounting type packaging structure.

[Explanation of symbols]

 1,1a LSI chip 2 Heat dissipation pad 3 Solder bump 4 Heat sink 5 Base board 6 Base board side connection pad 7 Electrical connection pad 8,8a Wire 9 Resin coat 10 Heat dissipation fin 11 Lead terminal 12 Motherboard 13 Heat dissipation via 14 Heat conduction Material 15 Buffer material 16 TAB 17 Cap 18 Cavity 19 Pattern 20 Parts

Claims (5)

[Claims] 1. An LSI chip having a heat radiation pad in addition to an external electrical connection pad. 2. An LSI chip, which is mounted on a base substrate by a connection through either or both of a bonding wire and a bump, and which has a heat dissipation pad in addition to an external electrical connection pad, and this LSI chip 2. A packaging structure for an LSI chip, comprising: a heat sink thermally connected to the heat radiation pad via a low thermal resistance member; and a heat radiation fin in thermal contact with the heat sink. 3. The low thermal resistance member is a solder bump,
The connection between the electrical connection pad and the base substrate is performed by wire bonding, the heat sink is connected to the LSI chip by the solder bump, and the LSI is exposed with the upper surface of the heat sink exposed.
3. The packaging structure for an LSI chip according to claim 2, wherein the chip and the heat sink are resin-coated, and the heat radiation fins are disposed on the heat sink. 4. The low thermal resistance member is a wire, and the electrical connection pad and the base substrate are connected by wire bonding, and the wire is used to connect the heat dissipation pad of the LSI chip and the LSI chip. 3. The packaging structure for an LSI chip according to claim 2, wherein the heat sink arranged in the periphery is connected, and the heat sink and the heat radiation fin are connected in a peripheral portion of the LSI chip. 5. The low thermal resistance member is a solder bump,
The connection between the electrical connection pad and the base substrate is performed by wire bonding, the heat sink is made of an insulating base material having good thermal conductivity, and the heat dissipation pattern formed on the insulating base material is the solder bump. Is connected to the LSI chip by means of which electrical components are electrically connected to a predetermined wiring pattern provided in advance on the insulating base material, and the heat radiation fins connected to the heat sink are the LS.
3. The packaging structure for an LSI chip according to claim 2, wherein the peripheral part of the I chip is capped on the base substrate.