Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material
Reexamination Certificate
2001-07-16
2002-12-31
Quach, T. N. (Department: 2814)
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
To form ohmic contact to semiconductive material
C438S623000, C438S624000, C438S687000, C438S788000
Reexamination Certificate
active
06500752
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device and a semiconductor device manufacturing method and, more particularly, a semiconductor device manufacturing method for forming a wiring buried insulating film for burying a wiring formed of a copper film or formed mainly of a copper film, and an inter-wiring layer insulating film that has barrier property to copper.
2. Description of the Prior Art
In recent years, the miniaturization and the reduction in thickness of the pattern are required with the higher integration degree and the higher density of the semiconductor integrated circuit devices. In addition, since the higher speed of the data transfer rate is also required.
Therefore, the insulating film having the low dielectric constant (referred to as a “low dielectric constant insulating film” hereinafter) and the small RC delay is employed. As such insulating film, there are the SiOF film having the relative dielectric constant 3.5 to 3.8, the porous SiO
2
film having the relative dielectric constant 3.0 to 3.1, etc., for example.
In the meanwhile, the wiring material is being changed from the conventional aluminum (Al) to the wiring formed of the copper (Cu) film having a low electric resistance or formed mainly of the copper film (referred to as a “copper wiring” hereinafter).
Therefore, in order to manufacture the semiconductor device having the multi-layered copper wiring, the low dielectric constant insulating film is formed as the interlayer insulating film on the copper wiring in the prior art. In this case, since normally the copper is ready to diffuse from the copper wiring into the low dielectric constant insulating film, the leakage current between upper and lower wirings is increased. Accordingly, in order to prevent the diffusion of the copper element into the low dielectric constant insulating film, the barrier insulating film containing Si and N or Si and C is often interposed between the copper wiring and the low dielectric constant insulating film.
However, the insulating film containing Si and N has the high relative dielectric constant. Therefore, even if such insulating film of the thinner film thickness is employed as the barrier insulating film, the dielectric constant of the overall interlayer insulating film is increased.
Also, the relative dielectric constant of the barrier insulating film containing Si and C is relatively low such as about 5 rather than the barrier insulating film containing Si and N. But such barrier insulating film containing Si and C cannot sufficiently suppress the increase in the leakage current. In this case, in order to suppress sufficiently the leakage current, further the oxygen must be introduced into the barrier insulating film containing Si and C.
The leakage current can be reduced to a sufficient level by doing so. However, the new problem is caused such that the surface of the copper wiring is oxidized and thus the barrier insulating film and the low dielectric constant insulating film are easily peeled off.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a semiconductor device and a semiconductor device manufacturing method capable of preventing peeling-off of an insulating film for covering a wiring made of only or mainly a copper film and achieving a low dielectric constant of an interlayer insulating film between wirings made of copper film etc. while maintaining a high barrier characteristic to a copper and a small leakage current, like the silicon nitride film, when an inter-wiring layer insulating film into which a connecting conductor is buried and a wiring-buried insulating film into which the copper wiring is buried are formed.
Advantages that can be achieved by the configuration of the present invention will be explained hereunder.
The PE-CVD TMS SiO
2
film according to the present invention has a peak of an absorption intensity of an infrared rays in a range of a wave number 2270 to 2350 cm
−1
, a film density in a range of 2.25 to 2.40 g/cm
3
, and a relative dielectric constant in a range of 3.3 to 4.3.
According to the experiment by the inventor of the present invention, the PE-CVD TMS SiO
2
film having the aforementioned characteristics has a high mechanical strength, is dense, has a high water resistance, and has a small content of moisture similarly to a silicon nitride film, and is a lower relative dielectric constant than the silicon nitride.
The semiconductor device of the present invention has a protection layer covering a wiring made only or mainly of a copper film, and the protection layer is formed of the PE-CVD TMS SiO
2
film having the aforementioned characteristics. Accordingly, since the protection layer is dense similarly to a silicon nitride, it can prevent the copper from diffusing from the wiring to a periphery thereof.
Further, an inter-wiring layer insulating film having the aforementioned characteristics is interposed between the lower wiring and the upper wiring. Therefore, the inter-wiring layer insulating film can prevent the copper from diffusing from the wiring to a periphery thereof, while the semiconductor device maintains a lower dielectric constant.
Moreover, the semiconductor device has a main insulating film, protection layers covering it in both a lower surface and an upper surface. In other words, the protection layers having the aforementioned characteristics are interposed both between the lower wiring and the main insulating film and between the upper wiring and the main insulating film, respectively. Therefore, the protection layers can prevent the copper from diffusing from the wirings to the main insulating film.
Further, employing a porous insulating film or a coating insulating film having a lower dielectric constant as the main insulating film results in preventing the copper from diffusing from the wirings to the main insulating film, while maintaining a lower dielectric constant.
The insulating film is formed by plasmanizing the film forming gas, that consists of any one selected from the group consisting of the alkoxy compound having Si—H bonds and the siloxane having Si—H bonds and any one oxygen-containing gas selected from the group consisting of O
2
, N
2
O, NO
2
, CO, CO
2
, and H
2
O, to react.
According to the experiment, it is found that the silicon-containing insulating film, that formed by plasmanizing the film forming gas that consists of any one selected from the group consisting of the alkoxy compound having Si—H bonds and the siloxane having Si—H bonds and any one oxygen-containing gas selected from the group consisting of O
2
, N
2
O, NO
2
, CO, CO
2
, and H
2
O to react, is dense, is excellent in the water resistance, and has the small amount of contained moisture in the film, that are equivalent to the silicon nitride film, and has the smaller relative dielectric constant than the silicon nitride film.
Therefore, in the method of manufacturing the semiconductor device in which the inter-wiring layer insulating film is put between the lower wiring-buried insulating film into which the lower wiring formed of the copper film or formed mainly of the copper film is buried and the upper wiring-buried insulating film into which the upper wiring formed of the copper film or formed mainly of the copper film is buried, the inter-wiring layer insulating film is formed by the above film forming condition. In other words, since the inter-wiring layer insulating film is interposed between the lower wiring and upper wiring, the diffusion of the copper from the lower wiring and the upper wiring can be prevented without the barrier insulating film and also the semiconductor can achieve the lower dielectric constant in the overall insulating film between the wirings.
Also, the main insulating films and the protection layers made of the silicon-containing film of the present invention are laminated alternatively in this order from a bottom to form two or more inter-wiring layer insulating films and two or more wiring buried insulating films alternatively in t
Aoki Junichi
Koromokawa Takashi
Maeda Kazuo
Oku Taizo
Yamamoto Youichi
Canon Sales Co., Inc.
Lorusso & Loud
Quach T. N.
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