JPH06151659A - Lsi package - Google Patents

Abstract

PURPOSE:To activate ventilation or heat discharge and improve the radiation characteristics at the center part of an LSI package by a method wherein the lengths of columns for radiation are gradually increased from one side to the other. CONSTITUTION:A radiation fin 10 which has a number of columns which are arranged so as to form a lattice shape in a plan view and has a column 11 which has a larger diameter than those of the other columns at its center is attached to the top side of an LSI package main part 1. With such a construction, the columns on the downstream side can be also exposed directly to air flow from outside, so that the radiation characteristics can be improved. Further, if the columns are hollow and their top parts are opened, heated air can be discharged from the tops of the columns, so that the radiation characteristics can be improved. Moreover, a ventilation hole through which air is introduced into the columns is provided on the side of the lower parts of the columns to prevent the heat from being kept inside, so that the radiation characteristics can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LSI package having a heat sink for heat dissipation.

[0002]

2. Description of the Related Art In recent years, large-scale semiconductor integrated circuits (hereinafter referred to as LS
It is possible to realize various functions by the progress of manufacturing microfabrication technology and the development of circuit technology. As this circuit technology, for example, p-type MOSFET
There is a complementary metal oxide film semiconductor (hereinafter referred to as CMOS) circuit using a MOSFET and an n-type MOSFET, a BiCMOS circuit in which a CMOS and a bipolar transistor are formed on one chip to form a circuit, and particularly, these CMOS and BiCMOS. The logic circuit is configured such that no current flows in a steady state, and consumes power only during operation. Therefore, low power consumption and high-speed operation are possible.

Generally, in the case of an LSI package using silicon, the maximum junction temperature Tj of the chip is required from the viewpoint of ensuring reliability.
It uses _max as an index and is expressed by the following formula. Tj _max = Ta _max + Pd _max (θjc + θca) = 100 to 125 [° C.] (1) where Ta _max is the maximum ambient temperature for operating the LSI, Pd _max is the allowable power consumption of the LSI, and θjc is from the LSI chip. The thermal resistance up to the package in which the LSI chip is mounted, and θca represent the thermal resistance from the package to the surrounding atmosphere. Here, θjc and θca have unique values depending on the package used and the usage environment.

For example, a 281-pin ceramic PGA ( P in
Request power dissipation Pd _max in the case of using a G rid A rray) package. The thermal resistance is θjc + θca = 30 ° C / W in the normal condition without fins and Tj _max = 100.
℃, Ta _max = 75 ℃ (TTL ( T ransistor T ransisto
r L guaranteed temperature value of product of the semiconductor integrated circuit typified by ogic)) that becomes a Pd _max = 0.83W.

The operating frequency of the LSI is increasing year by year (Nikkei Microdevice, April 1991, pp-38-50), and the power consumption is also increasing accordingly. Need to raise. Allowable power consumption Pd
_As a method of increasing _max , for example, 1 W or more, it is conceivable to reduce Ta _max or decrease the thermal resistances θjc and θca of the package. Generally θ
A method of reducing ca (thermal resistance from the package to the surrounding atmosphere) is adopted. For example, "Package Lineup" Gate Array Standard Cell, NEC, 1987
September edition ",""GMICRO F32 / 300 MPU -MB92301-" TRON
NOW ~ All products related to TRON specifications ~, Published by TRON Association, pp2
2-23, December 12, 1990 ", a fin for heat radiation is attached to the package and θca is reduced by forced air blow from the outside.

FIG. 1 is a schematic view showing this conventional LSI package, FIG. 1 (a) is a sectional view thereof, and FIG.
Shows its plan view. In FIG. 1, reference numeral 1 denotes a package body, and a large number of lead pins 2, 2, ... Are attached to the lower outer peripheral portion of the package body 1. An LSI chip 4 is mounted on the center of the package body 1, and the LSI chip 4 and the package body 1 are connected by a metal wire 5. And this mounting part is a lid 3
It is covered by.

On the upper side of the package body 1, as a heat sink, a large number of cylinders are arranged in a grid pattern in a plan view, and a radiating fin 6 having a cylinder having a larger diameter than the other cylinders is attached to the central portion. As a result, the heat radiation effect can be obtained regardless of the direction in which the wind is blown. Therefore, for example, when the LSI is mounted on the printed circuit board, there is an advantage that the thermal design of the housing of the device can be facilitated.

[0008]

However, in the shape of the heat radiation fins 6 in the conventional LSI package, there are variations in heat radiation characteristics between the windward side and the leeward side, for example, the outer peripheral portion and the central portion. This is because the wind blown into the central portion is preheated in the outer peripheral portion, so that heat is accumulated in the central portion and the heat radiation characteristics are deteriorated. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an LSI package including a heat sink for heat radiation capable of improving the heat radiation characteristics in the central portion.

[0009]

An LSI package according to a first aspect of the present invention is provided with a heat sink for heat dissipation having a large number of cylinders, and in the LSI package on which an LSI chip is mounted, the length of the cylinder is changed from one side to the other side. The feature is that it gradually becomes longer toward the side. L according to the second invention
The SI package is provided with a heat sink for heat dissipation having a large number of cylinders, and in the LSI package on which the LSI chip is mounted, the inside is hollow and the tip is provided with a cylinder having an open end. An LSI package according to a third aspect of the present invention is provided with a heat sink for heat dissipation having a large number of cylinders, and in the LSI package on which an LSI chip is mounted, the inside is hollow, the front end is open, and a vent hole is formed on the side surface of the base end. It is characterized by including a column provided with.

[0010]

According to the first aspect of the invention, the wind blown from the outside can be directly received even in the leeward portion, so that the heat radiation characteristic can be improved. In the second invention,
By letting the warmed air escape above the heat sink, the heat dissipation characteristics can be improved. According to the third aspect of the present invention, the warm air is forcedly released to the upper side of the heat sink, so that heat can be prevented from being accumulated and the heat radiation characteristics can be improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. 2A and 2B are schematic diagrams showing a first embodiment of an LSI package according to the present invention, FIG. 2A is a sectional view thereof, and FIG. 2B is a plan view thereof. In FIG. 1, reference numeral 1 denotes a package body, and a large number of lead pins 2, 2, ... Are attached to the lower outer peripheral portion of the package body 1. The LSI chip 4 is provided at the center of the package body 1.
Are mounted, and the LSI chip 4 and the package body 1 are connected by a metal wire 5. The mounting portion is covered by the lid 3.

In the LSI package according to the present invention, a large number of cylinders are arranged on the upper side of the package body 1 in a grid pattern in a plan view, and a radiation fin 10 having a cylinder 11 having a diameter larger than those of the other cylinders is provided in the central portion. It is installed.
When the air is blown from the left side as shown by the white arrow in this figure, the cylinder A (, A ...) in the leftmost column to the cylinder B (, B ...), C (, C ...) in the next column, Cylinder D (, D ...), Cylinder E
(, E ...), cylinder F (, F ...), cylinder G (, G ...), cylinder H (,
H ...) and the column I (, I ...) in the rightmost column has a structure in which the height is high in this order.

In such a structure, it is possible to directly receive the wind blown from the outside even in the leeward side portion, and the heat dissipation characteristic is improved.

FIG. 3 is a schematic diagram showing a second embodiment of the LSI package according to the present invention, FIG. 3 (a) is a sectional view thereof, and FIG. 3 (b) is a plan view thereof. In the second embodiment,
Each of the columns of the heat radiation fin 12 has the same height, has a hollow inside, and has an open top. Further, the cylinder 13 at the center has the same shape as the conventional one. Other configurations are the same as those shown in FIG. 2, and the same reference numerals are given and the description thereof is omitted.

In such a structure, the heat radiation characteristics are improved by letting the warmed air escape above the radiation fins 12. Similar to the radiation fin 10 shown in FIG. 2, a better effect can be obtained by increasing the height of the column from the windward side to the leeward side.

FIG. 4 is a schematic diagram showing a third embodiment of an LSI package according to the present invention, FIG. 4 (a) is a sectional view thereof, and FIG. 4 (b) is a plan view thereof. In the third embodiment,
Each of the columns of the heat radiation fin 14 has the same height, has a hollow inside, has an open top, and is provided with a vent hole 14a for taking in wind on the lower side surface of the column. Also, the central column
15 is the same form as the conventional one. Other configurations are the same as those shown in FIG. 2, and the same reference numerals are given and the description thereof is omitted.

In such a structure, the warm air is forced to escape above the heat radiating fins 12 to prevent heat buildup and improve the heat radiating characteristics. Similar to the radiation fin 10 shown in FIG. 2, a better effect can be obtained by increasing the height of the column from the windward side to the leeward side.

[0018]

As described above, in the LSI package according to the present invention, by changing the shape of the heat sink for heat radiation, it is possible to activate ventilation or heat emission and improve the heat radiation characteristics. The present invention has excellent effects.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a conventional LSI package.

FIG. 2 is a schematic diagram showing a first embodiment of an LSI package according to the present invention.

FIG. 3 is a schematic diagram showing a second embodiment of an LSI package according to the present invention.

FIG. 4 is a schematic diagram showing a third embodiment of an LSI package according to the present invention.

[Explanation of symbols]

 1 Package body 2 Lead pin 3 Lid 4 LSI chip 5 Metal wire 10, 12, 14 Heat dissipation fin 14a Vent hole

Claims (3)

[Claims] 1. An LSI package including a heat sink for heat dissipation, which has a large number of cylinders, wherein the length of the cylinders is gradually increased from one side to the other side. LSI package. 2. An LSI package comprising a heat sink for heat dissipation having a large number of cylinders, wherein the inside of the LSI package is a cavity, and the tip has an open cylinder. . 3. In an LSI package having a heat sink for heat dissipation having a large number of cylinders, the inside of which is a hollow, the tip end is open, and a vent hole is provided on the side surface of the base end in an LSI package. An LSI package comprising: