Semiconductor device manufacturing: process – Making field effect device having pair of active regions... – Having insulated gate
Reexamination Certificate
1998-05-19
2001-09-04
Lee, Eddie (Department: 2815)
Semiconductor device manufacturing: process
Making field effect device having pair of active regions...
Having insulated gate
C438S396000, C438S502000, C438S800000
Reexamination Certificate
active
06284587
ABSTRACT:
BACKGROUND TO THE INVENTION
1. Field of the Invention
The present invention relates to a fabricating method for capacitor of a semiconductor device.
2. Description of the Related Art
The conventional method of building a capacitor into a semiconductor device has involved forming a dielectric film in the shape of a tantalum oxide, barium-strontium titanate or other oxide film on to a bottom electrode of polysilicon, metal or oxide conductive layer, then forming a top electrode of ruthenium, iridium or a similar substance.
When fabricating capacitors of this sort it is common to implement heat-treatment within oxygen, activated oxygen or ozone after formation of the dielectric film. This serves to increase dielectric constant by crystallizing the dielectric film, and to reduce current leakage by compensating oxygen deficit (cf. Japanese Laid-Open Publication No.82915/97).
FIG. 16
is cross-section illustrating an example of the configuration of a conventional semiconductor device.
As
FIG. 16
shows, a device isolating silicon oxide film
1602
and a diffusion layer
1603
forming part of a MOS transistor or a similar device are formed on the surface of a silicon wafer
1601
, followed by an interlayer insulator
1604
. Then, after a contact hole
1605
has been formed in the film
1604
, a bottom electrode
1606
is formed in the shape of an interlayer wiring film
1606
a
and conductive layer
1606
b
in polysilicon or a similar substance. Next, a tantalum oxide or other dielectric film
1607
is formed over the whole surface, and the capacitor is heat-treated in oxygen, activated oxygen or ozone as mentioned above. Finally, it is completed with the formation of a top electrode
1608
having a film of ruthenium, iridium or a similar substance which covers all the film
1607
.
However, conventional capacitors such as those illustrated in
FIG. 16
suffer from the following defects.
As has been stated above, it has been common conventional practice to subject the capacitor to heat-treatment in an atmosphere of oxygen or the like after formation of the film
1607
. As a result it sometimes happens that a silicon oxide layer
1606
c
is formed in the vicinity of the interfacial boundary between the films
1606
a
and
1606
b
. This leads to the formation, in addition to the above mentioned capacitor, of another capacitor comprising the conductive films
1606
a
and
1606
b
along with the insulation layer
1606
c
, so that two serially connected capacitors exist within the semiconductor device. Consequently, the total dielectric constant of the capacitors formed in such a semiconductor device falls below the intended level.
Moreover, it sometimes happens that during heat-treatment the layer
1606
b
oxidizes, thereby tending to increase the unevenness of the surface and resultant current leakage.
Conversely, the oxygen within the film
1607
may be released during heat-treatment, leading to oxygen deficit and consequent increased current leakage.
If the conductive layer
1606
b
is formed of a different material such as a metal or a conductive oxide, it may happen that a barrier layer (not shown in the drawing) forms between the films
1606
b
and
1606
c
. In such cases, heat-treatment causes this barrier layer to oxidize into a dielectric layer, so that there is a risk of a capacitor being formed between the layers
1606
b
and
1606
a
. The result again is that the total dielectric constant of the capacitors falls below the intended level.
Such defects combine to lower the yield of the semiconductor device, and result in increased costs.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a fabricating method for a semiconductor device whereby it is possible to prevent reduced yield caused during heat-treatment.
The fabricating method of a semiconductor device to which the present invention pertains comprises forming a laminated structure, having at least a first film for use in forming an oxidized dielectric film which contains an oxidizable substance for the purpose of forming an oxidized dielectric film, and a second film for use in supplying oxygen to said first film; and supplying oxygen from said second film to said first film by virtue of heat-treatment of said laminated structure within an atmosphere which does not contain oxygen.
The present invention allows the film for use in forming an oxidized dielectric film to oxidize as a result of heat-treatment within an atmosphere which does not contain oxygen.
REFERENCES:
patent: 4521951 (1985-06-01), Croset et al.
patent: 04171975a (1992-06-01), None
patent: 08330512a (1995-05-01), None
patent: 9-82915 (1997-03-01), None
Takehiro Shinobu
Yamauchi Satoshi
Yoshimaru Masaki
Brock II Paul E
Jones Volentine PLLC
Lee Eddie
OKI Electric Industry Co., Ltd.
LandOfFree
Fabricating method for semiconductor device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fabricating method for semiconductor device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fabricating method for semiconductor device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2493043