JPH10199882A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid deteriorating the characteristics of a semiconductor device, due to the heat by effectively radiating the heat stored in layer insulation films of a multilayer wiring structure. SOLUTION: Dummy wiring films 3A, 5A, 7A, 9A are provided to form wiring layers of a multilayer structure and are interconnected through dummy through-holes 4b, 6b, 8b. The heat generated in a semiconductor substrate 1 is transmitted through the dummy wiring films and dummy through-holes to an upper wiring layer, thereby efficiently radiating from the surface of a multilayer structure. A heat sink 12 is provided on the topmost layer, and the dummy wiring 9A is connected through the dummy through-holes 19b to this heat sink to effectively radiate heat. When a low-thermal conductivity and low-dielectric const. layer insulation film is used for each wiring layer for the purpose of realizing a highly integrated semiconductor device, the temp. rise of the device is suppressed to avoid causing troubles of the device, due to heat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device,
In particular, the present invention relates to a semiconductor device having improved heat radiation characteristics in a semiconductor device having a fine multilayer wiring structure.

[0002]

2. Description of the Related Art In recent years, multilayer wiring has been promoted along with the high integration of semiconductor devices. In this multi-layer wiring structure, since the wiring films arranged in multiple layers are insulated from each other by an interlayer insulating film, the heat generated in the semiconductor element due to the low thermal conductivity of the interlayer insulating film is applied to these interlayer insulating films. It accumulates, and this causes a malfunction of the device and causes a problem that characteristics are deteriorated.
In particular, recently, a film having a low dielectric constant has been used as an interlayer insulating film in order to suppress an increase in capacitance between wirings in a multilayer structure. However, such a film having a low dielectric constant has a low thermal conductivity. However, the heat release efficiency is poor, and the heat tends to accumulate. In this case, it is conceivable to arrange a heat sink on the wiring layer to enhance the heat radiation effect, but it is not possible to increase the thermal conductivity inside the interlayer insulating film of the multilayer wiring structure,
Particularly, heat accumulation in the lower wiring layer becomes significant, and as a result, it cannot be an effective solution.

On the other hand, Japanese Patent Laying-Open No. 5-267295 proposes a structure in which a dummy wiring film is provided in a multilayer wiring structure. The purpose of this dummy wiring film is to flatten the multilayer wiring structure. However, the portion where the dummy wiring film is formed is replaced with a metal having a high thermal conductivity from an interlayer insulating film having a low thermal conductivity. This is effective in improving the thermal conductivity of the insulating film and improving the heat dissipation of the semiconductor device as a whole. However, since there is a limit in the arrangement area of the dummy wiring film, it is difficult to obtain an expected improvement effect.

[0004]

As described above, in the conventional multilayer wiring structure, the heat dissipation of the heat generated in the semiconductor element is low due to the low thermal conductivity of the interlayer insulating film for insulating between the wirings. There is a problem of deteriorating characteristics. In a semiconductor device having a dummy wiring film, the volume of the interlayer insulating film is reduced by the dummy wiring film, which is advantageous in improving heat radiation characteristics, but is not a fundamental solution.

An object of the present invention is to provide a semiconductor device capable of effectively radiating heat accumulated in an interlayer insulating film of a multilayer wiring structure and preventing deterioration of characteristics due to heat of a semiconductor device. .

[0006]

According to the present invention, in a semiconductor device having a multilayer wiring structure in which a plurality of wiring layers are stacked and arranged, a dummy wiring film is formed on each of the wiring layers together with a wiring film. Are interconnected between upper and lower wiring layers via dummy through holes provided in each interlayer insulating film for insulating each wiring layer. In the present invention, it is preferable that a heat sink is provided on an uppermost wiring layer, and the uppermost dummy wiring film is connected to the heat sink through a dummy through hole. In the present invention, the wiring film and the dummy wiring film are formed of a metal having a high thermal conductivity, and the interlayer insulating film is formed of an insulating material having a low dielectric constant.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a first embodiment of the present invention. Here, an example in which the present invention is applied to a multilayer wiring structure having a four-layer structure is shown. An element (not shown) is formed on the semiconductor substrate 1, and a base insulating film 2 is formed on the semiconductor substrate 1.
Is formed, and a first wiring metal film 3 is formed on the underlying insulating film 2.
Are formed in a required pattern. As the first wiring metal film 3, for example, an aluminum alloy having a thickness of 10000 ° is used. Then, a first interlayer insulating film 4 is formed so as to cover the first wiring metal film 3. As the first interlayer insulating film 4, for example, a film obtained by forming a fluorine-containing silicon oxide film to a thickness of 10,000 ° is used. A through hole 4a is formed at a required portion of the first interlayer insulating film 4, and a second wiring metal film 5 is formed on the first interlayer insulating film 3 including the through hole 4a. Hereinafter, similarly, the second interlayer insulating film 6, the third wiring metal film 7, the third interlayer insulating film 8, the fourth wiring metal film 9, and the fourth interlayer insulating film 10 are formed, and the passivation film 11 is formed at the top. Thus, a multilayer wiring structure having a four-layer structure is formed. The passivation film 11 has a configuration in which, for example, a silicon oxide film is formed to a thickness of 500 °. The wiring metal film and the interlayer insulating film of each layer are made of the materials described above.

Here, the first to fourth wiring metal films 3, 5, 7 and 9 are respectively provided with dummy wiring metal films 3A, 5A and 7 in regions where the original wiring metal film is not formed.
A and 9A are formed. These dummy wiring metal films 3A, 5A, 7A, 9A are made of respective wiring metal films 3, 5, 7,.
9 and the same thickness. For example, the original wiring metal film is formed by forming a metal material on the entire surface and then etching the metal material by photolithography technology. At this time, a dummy wiring metal film may be formed at the same time. Further, each of the interlayer insulating films 4 of the first to third wiring layers 4,
6 and 8, dummy through holes 4b, 4a, 6a, 8a are provided separately from the original through holes 4a, 6a, 8a between the wiring metal films.
6b, 8b are formed, and the upper and lower dummy wiring metal films 3 are formed by the dummy through holes 4b, 6b, 8b.
a, 5a, 7a, 9a are connected to each other.

Therefore, in the configuration of the first embodiment, the heat generated by the elements of the semiconductor substrate 1 is transmitted to the wiring metal film 3, the interlayer insulating film 4, and the dummy wiring metal film 3A in the first wiring layer. Each is transmitted. The interlayer insulating film 4
Since it is composed of a fluorine-containing silicon oxide film which is a low dielectric constant film having a low thermal conductivity, heat is easily accumulated. However, the heat transmitted to the wiring metal film 3 and the dummy wiring metal film 3A is low. Wiring metal film 5 in the upper layer (second wiring layer) via through hole 4a and dummy through hole 4b, respectively.
To the dummy wiring metal film 5A. Thereby, the effect of transferring heat to the upper layer can be enhanced by the provision of the dummy wiring metal film, as compared with the case where only the original wiring metal film exists. The heat transferred to the second wiring layer is similarly transferred to the wiring metal film 5, the dummy wiring metal film 5A.
Through the through hole 6a and the dummy through hole 6b to the third wiring layer, and further similarly to the fourth wiring layer. Therefore, the heat of the semiconductor substrate 1 is reduced by the wiring metal films 3, 5, 7, 9 and the dummy wiring metal films 3A, 5A.
The light is efficiently transmitted to the uppermost fourth wiring layer through A, 7A, and 9A, and is radiated from the uppermost layer surface. Thus, even in a semiconductor device having a multilayer wiring structure of a low dielectric constant interlayer insulating film in which heat easily accumulates, it is possible to prevent the characteristics of the semiconductor device from deteriorating due to high temperatures.

FIG. 2 is a sectional view of a second embodiment of the present invention. This embodiment also shows an example in which the present invention is applied to a four-layer multi-layer wiring structure as in the first embodiment, in which a base insulating film 2 is formed on a semiconductor substrate 1 and first to A fourth wiring layer is formed. Note that the same reference numerals are given to portions equivalent to those in the first embodiment, and detailed description thereof is omitted. In this second embodiment,
The uppermost passivation layer is not formed. Instead, a heat sink 12 made of a metal plate is arranged, and the heat sink 12 and the second heat sink 12 are formed by a dummy through hole 10b formed in the interlayer insulating film 10 of the fourth wiring layer. The dummy wiring metal films 9A of the four wiring layers are connected.

Also in the second embodiment, the heat generated in the elements of the semiconductor substrate 1 is transferred from the first wiring layer to the fourth wiring layer by the wiring metal films 3, 5, 7, 9 of the respective wiring layers. And dummy wiring metal films 3A, 5A, 7A, 9A and through holes 4a, 6a, 8a and dummy through holes 4b, 6b,
8b. Then, of the heat finally transmitted to the fourth wiring layer, the heat transmitted to the wiring metal film 9 is transmitted to the heat sink 12 through the interlayer insulating film 10, and the heat transmitted to the dummy wiring metal film 9A is the dummy heat. The heat is directly transmitted to the heat sink 12 through the through hole 10b, and is radiated from the entire surface of the heat sink 12, respectively. This makes it possible to efficiently radiate heat even when the thermal conductivity of the interlayer insulating film of each wiring layer is low.
In this embodiment, by radiating the heat from the heat sink 12, it is possible to radiate the heat transmitted to the fourth wiring layer with higher efficiency than in the first embodiment.

As shown in FIG. 3, even in the first embodiment, even if the heat sink 12 is arranged above the uppermost passivation film 11, the structure up to the dummy wiring metal film 9A in the fourth wiring layer can be obtained. The transmitted heat is transmitted to the heat sink 12 via the passivation film 11, and is radiated from here. As a result, FIG.
It is possible to enhance the heat radiation effect as compared with the configuration of the above.

[0013]

As described above, according to the present invention, a dummy wiring film is provided in each of the wiring layers having a multilayer structure, and the respective dummy wiring films are connected to each other through dummy through holes. Heat can be transferred to the upper wiring layer via the dummy wiring film and dummy through hole,
Heat can be efficiently radiated from the surface of the wiring structure. Further, by providing a heat sink on the uppermost layer and connecting a dummy wiring to the heat sink through a dummy through hole, heat radiation can be more effectively performed. Thus, even when an interlayer insulating film having a low thermal conductivity and a low dielectric constant is used for each wiring layer for the purpose of high integration of the semiconductor device, the temperature rise of the device can be suppressed, and the semiconductor device due to heat can be suppressed. There is an effect that a failure can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a second embodiment of the present invention.

FIG. 3 is a diagram showing a modification of the first embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2 Base insulating film 3,5,7,9 Wiring metal film 3A, 5A, 7A, 9A Dummy wiring metal film 4,6,8,10 Interlayer insulating film 4a, 6a, 8a Through hole 4b, 6b, 8b , 10b Dummy through hole 11 Passivation film 12 Heat sink

Claims (3)

[Claims] In a semiconductor device having a multilayer wiring structure in which a plurality of wiring layers are stacked and arranged, a dummy wiring film is formed on each of the wiring layers together with a wiring film, and these dummy wiring films are formed on the respective wiring layers. A semiconductor device which is interconnected between upper and lower wiring layers via dummy through holes provided in respective interlayer insulating films for insulating the same. 2. The semiconductor device according to claim 1, wherein a heat sink is provided on an uppermost wiring layer, and the uppermost dummy wiring film is connected to the heat sink via a dummy through hole. 3. The semiconductor device according to claim 1, wherein the wiring film and the dummy wiring film are formed of a metal having a high thermal conductivity, and the interlayer insulating film is formed of an insulating material having a low dielectric constant.