JPH06125022A - Semiconductor device having heat radiating section and its manufacture - Google Patents

Abstract

PURPOSE:To enable a semiconductor device to sufficiently radiate heat and, at the same time, to reduce the size and increase the packing density of the device by forming recessing and projecting sections for radiating heat on the surface of the substrate of the device on the opposite side of the element forming surface. CONSTITUTION:Since recessing and projecting sections 2a and 2d for radiating heat are formed on a silicon substrate 1 itself, a sufficiently large heat radiating area can be obtained and, since the heat diffusing section is constituted of the substrate 1 itself, highly efficient heat radiation can be realized. In addition, since the sections 2a-2d are formed by directly forming heat radiating fins on the substrate 1, efficient heat radiation can be obtained by utilizing the high thermal conductivity of silicon. Moreover, since no large external heat radiating plate is required, this semiconductor device can be reduced in size and increased in packing density. The sections 2a-2d can be easily formed by etching the silicon of the substrate 1 through a commonly used process, such as the RIE, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method for manufacturing the same, and more particularly to a semiconductor device having a heat dissipation portion and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor device, a heat dissipation portion has been formed. For example, in a conventional high output device, a heat radiating plate is externally attached to the outside of the device to radiate heat. For example, as schematically shown in FIG.
A structure in which metallic heat radiation fins 12a, 12b ... Are attached to a part 11 of a package for housing the device is adopted.

The reason why such a heat radiating portion is required is as follows. As schematically shown in FIG.
The active portion A on which is mounted is small on the chip, and many elements are formed in the semiconductor device 13. Therefore, heat is generated during operation, and this is generated in the active portion A having a small heat dissipation and a small area. It accumulates and accumulates heat, which may lead to malfunction.
This problem is particularly important in high power devices that generate a large amount of heat. Therefore, by disposing the heat radiating portion, the heat is dissipated, and the problem associated with the heat generation is solved.

[0004]

In the prior art, since the heat radiating portion such as the heat radiating plate is externally attached, it is necessary to provide a space for attaching the heat radiating plate or the like, which makes the device compact and highly integrated. Was being hampered.

Particularly, a high-power device has a large heat radiation,
Therefore, in the past, high integration could not always be achieved, and IC could not be realized in some cases.

The present invention solves the above-mentioned problems and achieves sufficient heat dissipation, and enables miniaturization and high density.
It is an object of the present invention to provide a semiconductor device that can meet the demand for high integration, and an object of the present invention is to provide a manufacturing method that can easily obtain such a semiconductor device.

[0007]

The invention according to claim 1 of the present application has a heat dissipation portion characterized in that an unevenness portion for heat dissipation is formed on a surface of a substrate opposite to an element formation surface. A semiconductor device, which achieves the above object by this configuration.

The invention of claim 2 of the present application is a semiconductor device in which an uneven portion for heat dissipation is formed on a surface of a substrate opposite to an element forming surface, and the uneven portion is formed by processing the substrate. It is a semiconductor device having a heat dissipation portion formed, and achieves the above object by this configuration.

The invention according to claim 3 of the present application is a method for manufacturing a semiconductor device having an uneven portion for heat dissipation on a surface opposite to an element forming surface on a substrate, wherein the substrate is processed by etching. A method of manufacturing a semiconductor device having a heat radiating portion, characterized by comprising a step of forming a heat radiating uneven portion, which achieves the above object.

In the present specification, the "irradiation unevenness portion" means a component portion formed in a convex shape or a concave shape so as to have a heat radiation function. The shape of the uneven portion is arbitrary. For example, it may be formed as a cylindrical projection, or may be formed in a cylindrical concave shape. Needless to say, it may be a prism or a fin-shaped convex portion (or a concave portion may be used). Also,
It may have a stepped shape or a U-shaped uneven portion.

The uneven portion for heat dissipation is formed on the surface of the substrate opposite to the element formation surface. However, in the case of a semiconductor device in which only one side of the substrate is the element formation surface, it is opposite to the element formation surface. A heat dissipation part is formed on the surface of the. When elements are formed on both sides of the substrate, no element is formed on the corresponding part of the surface on the opposite side to the part where the element of interest requiring heat dissipation is formed, and the heat dissipation part is placed here. Form.

In the invention of claim 2, when the unevenness portion is formed by processing the substrate itself to use as the heat radiation portion, the heat radiation portion can be formed by partially removing the substrate by etching or the like, or It can be formed by adding by vapor deposition or the like.

The method of manufacturing a semiconductor device according to claim 3, wherein the uneven portion is formed by etching the substrate to form a heat radiation portion.

[0014]

According to the inventions of the present application, the uneven portion for heat dissipation is
Since it is formed on the surface of the substrate opposite to the surface on which the elements are formed, no space is required unlike the technique of externally attaching a heat sink or the like. In addition, when an attempt is made to form a heat dissipation portion on the element formation surface, the element does not necessarily provide a sufficient heat dissipation area, but the present invention allows a sufficient heat dissipation area. Therefore, it is possible to achieve sufficient heat dissipation, save space, and realize miniaturization and high integration.

According to the second aspect of the present invention, since the uneven portion which is the heat radiation portion is formed by processing the substrate, the strength can be increased as compared with the case where a separate uneven portion is formed.

According to the third aspect of the present invention, since the substrate is etched to form the uneven portion which is the heat radiation portion, this semiconductor device can be easily manufactured by using the usual means (and the common equipment) in the normal semiconductor manufacturing process. This is advantageous because it is possible and the degree of freedom in processing is large as compared with the case of processing the element forming side.

According to the invention of the present application, high output devices (power devices, laser elements, etc.) can be integrated and highly integrated. It is not necessary to attach a heat sink after packaging and molding with an IC chip as in the conventional case. Alternatively, such conventional techniques can be used together to further increase the heat dissipation efficiency.

[0018]

EXAMPLES Examples of the invention of the present application will be described below. However, it should be understood that the present invention is not limited to the embodiments.

Embodiment 1 This embodiment is a high power IC, especially a high power MOS.
Each of the inventions of the present application is applied to the high output device. Of course, the present invention can be similarly applied to other power ICs, laser elements, optical ICs (heat radiation increases as the density of laser or light increases), and other semiconductor devices.

In this embodiment, as shown in a sectional view of FIG. 1, a device forming surface 1 is formed on a substrate 1 (a silicon substrate in this embodiment).
Surface on the opposite side to a (sometimes referred to as "heavy surface") 1b
It is a semiconductor device in which uneven portions 2a to 2d for heat dissipation are formed in the semiconductor device. Particularly, the uneven portions 2a to 2d are formed by processing the substrate 1. In particular, this is obtained by etching the substrate 1. This is an example in which the uneven portions 2a to 2d for heat dissipation are formed.

In FIG. 1, reference numeral 3 represents an element forming a device. The drawing is a schematic view, and in reality, the elements 3 are formed in various structures with high density.

In this embodiment, the uneven portion forming the heat radiating portion was formed by etching the substrate 1 so as to form a fin-shaped heat radiating plate. The fins may have any shape, depth, and spacing. These may be designed according to the semiconductor device, particularly according to the heat dissipation effect required for the semiconductor device.

According to this embodiment, the uneven portion 2 which is the heat dissipation portion
Since a to 2d are formed on the substrate 1 itself, the portion where the heat is diffused is the substrate 1 itself, so that efficient heat dissipation can be realized.

Further, in this embodiment, since the fins for heat dissipation are directly formed on the silicon substrate 1 to form the unevenness parts 2a to 2d for heat dissipation, it is possible to efficiently dissipate heat due to the high thermal conductivity of silicon.

Furthermore, since it is not necessary to attach a large heat dissipation plate to the outside, the device can be downsized and the density can be increased.

In the present embodiment, the uneven portions 2a to 2d are formed by etching, but this etching can be achieved by etching silicon by a usual process such as RIE. Since the uneven portions 2a to 2d to be formed also have a simple fin-like structure, they can be easily formed. As for the type, flow rate, power, etc. of the gas at the time of etching, the usual conditions for silicon at the time of forming the semiconductor device may be used.

When a high-power semiconductor device is formed as described above, even if the density is increased, the heat dissipation effect of the uneven portions 2a to 2d allows the operation to continue favorably without any special problem.
Good IC operation continued. No change in properties was observed at high temperatures. In addition, the device life could be extended.

As described above, in the present embodiment, the heat radiation uneven portions 2a to 2 are formed on the back surface 1b of the substrate 1 of the high power device.
The fin structure is directly formed by etching as d, which enables efficient heat dissipation and reduction of high-power devices.
It was sought if high density was possible.

[0029]

According to the invention of the present application, it is possible to provide a semiconductor device which can achieve sufficient heat dissipation, can be miniaturized and have a high density, and can meet the demand for high integration.
Further, it is possible to provide a manufacturing method capable of easily obtaining such a semiconductor device.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a semiconductor device according to a first embodiment.

FIG. 2 shows a conventional technique.

FIG. 3 shows the prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate (silicon substrate) 1a Element formation surface of a substrate 1b Surface opposite to the element formation surface of a substrate (back surface) 2a to 2d Concavo-convex portion

Claims (3)

[Claims] 1. A semiconductor device having a heat radiating portion, characterized in that an uneven portion for heat radiating is formed on a surface of a substrate opposite to an element forming surface. 2. A semiconductor device in which a heat-dissipating uneven portion is formed on a surface of a substrate opposite to an element formation surface, the uneven portion having a heat-dissipating portion formed by processing the substrate. A semiconductor device having. 3. A method of manufacturing a semiconductor device having a heat radiation uneven portion on a surface opposite to an element formation surface on a substrate, wherein the heat radiation uneven portion is formed by etching a substrate. A method of manufacturing a semiconductor device having a heat radiating portion, comprising: