Semiconductor device manufacturing: process – Coating of substrate containing semiconductor region or of... – Insulative material deposited upon semiconductive substrate
Reexamination Certificate
2001-08-30
2002-10-01
Chaudhuri, Olik (Department: 2813)
Semiconductor device manufacturing: process
Coating of substrate containing semiconductor region or of...
Insulative material deposited upon semiconductive substrate
C438S622000, C257S758000, C427S590000
Reexamination Certificate
active
06458719
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to the insulation film used between semiconductor device layers, and the low dielectric constant material having thermal resistance of a semiconductor device, which is applicable for electric circuit appliances.
Along with improvement in speed and high integration of a semiconductor device, the problem of signal retardation has become serious. The signal retardation is expressed with the product of resistance R of a wire and capacity C between wires and between layers. In order to suppress the retardation to the minimum, it is an effective means to lower the dielectric constant of an insulation film between layers, as well as to lower resistance of wiring.
Recently, in order to lower the dielectric constant of an insulation film between layers, there is proposed a method for forming an insulation film between layers using a silicon oxide film (SiOF film) wherein the fluorine atom is incorporated. Moreover, since an organic compound material can relatively lower dielectric constant, there is proposed a method for forming an insulation film between layers by using a parylene deposit film or a polyimide film wherein a fluorine atom is incorporated (Hideki Shibata, Densijyouhoutsuusin Gakkaishi Vol.80, No.3 p235(1997)).
By the way, the dielectric constant of the insulation film between layers becomes lower than that of the conventional film, when the insulation film between layers is formed by the above SiOF film. However, a dielectric constant thereof becomes about 3.2 to 3.5, capacity between wires can not be reduced and signal propagation de of wires can not be sufficiently prevented.
Moreover, the dielectric constant 2.7 is attained by using the film wherein the fluorine atom is incorporated into the polyimide and aryl ether polymer, when an insulation film between layers is formed with the organic compound material mentioned below. But it is not still sufficient. By using deposit film of parylene dielectric constant 2.4 can be attained, but the process for preparing a semiconductor device is limited, since thermal resistance is only about 200 to 300° C.
The dielectric constant of 2.0 to 2.5 has been reported in porous SiO
2
film. But there is a problem that mechanical strength (CMP polishing process resistance) is low due to high porosity, and a pore diameter varies.
Since thermal conductivity of these polymeric materials and porous SiO
2
film is lower than that of the conventional insulation film between layers of SiO
2
, there is a problem that the wiring life is degraded (electromigration) by the wire temperature rise.
As mentioned above, the insulation film between layers has been desired, which has low dielectric constant and is excellent in thermal resistance, mechanical strength, and the thermal conductivity. Concretely, in design-rule 0.13 to 0.10 &mgr;m, the film is required, which has mechanical strength and thermal conductivity not less than an SiO
2
film, dielectric constant of at most 2.4, and thermal resistance (thermal decomposition temperature) of at least 450° C.
SUMMARY OF THE INVENTION
The object of the present invention is to provide the low dielectric constant film having thermal resistance, which is excellent in thermal resistance, has low dielectric constant and can be applied to appliances of semiconductor device and electric circuit, and the process for forming the same.
The low dielectric constant film having thermal resistance of the present invention comprises molecules comprising boron, nitrogen, and hydrogen, wherein the number of nitrogen atom is 0.7 to 1.3 and the number of hydrogen atom is 1.0 to 2.2 based on one boron atom, and of which dielectric constant is at most 2.4.
The low dielectric constant film having thermal resistance of the present invention has thermal decomposition temperature of at least 450° C. in the above low dielectric constant film having thermal resistance.
The process for forming the low dielectric constant film having thermal resistance of the present invention is the process wherein the process for forming the low dielectric constant film having thermal resistance on the substrate surface is the process for forming the low dielectric constant film having thermal resistance according to chemical vapor deposition.
The process for forming the low dielectric constant film having thermal resistance of the present invention is the process wherein gas containing diborane and gas containing annonia are used as raw gas in the chemical vapor deposition in the process for forming the low dielectric constant film having thermal resistance.
The process for forming the low dielectric constant film having thermal resistance of the present invention is the process wherein gas containing diborane is used as raw gas in the chemical vapor deposition in the process for forming the low dielectric constant film having thermal resistance.
The insulation film between semiconductor layers of the present invention is the insulation film between semiconductor layers comprising the low dielectric constant film having thermal resistance.
The insulation film between semiconductor layers of the present invention is the insulation film between semiconductor layers obtained by the process for forming the low dielectric constant film having thermal resistance.
The semiconductor device of the present invention is the semiconductor device comprising the insulation film between semiconductor layers.
DETAILED DESCRIPTION
Example of the compound in the film of the present invention comprising molecules comprising boron, nitrogen and hydrogen, wherein the number of nitrogen atom is 0.7 to 1.3 and the number of hydrogen atom is 1.0 to 2.2 based on one atom of boron, is concretely borazine shown in the following formula (1) (which is called as inorganic benzene or borazol).
The compounds obtained by molecular propagation of the structure shown in the above formula (1) and the derivative structure as thereof as a basic unit are suitable for the low dielectric constant film having thermal resistance of the present invention. The low dielectric constant film having thermal resistance comprising the compounds can be applied for the insulation film between semiconductor layers, and by using the insulation film the excellent semiconductor device can be prepared.
The reasons why the material (or compound) of the present invention can lower the dielectric constant and achieve dielectric constant of at most 2.4 are follows.
That is, the dielectric constant &egr; is generally described with sum of polarization such as electron polarization, atom polarization, orientation polarization, and interface polarization. But it is sufficient to consider only the electron polarization and the atom polarization as polarization controlling dielectric constant, as long as there is no contribution of interfacial polarization in the high frequency region of at least 1 MHz in the present invention and there is used the material showing no orientation. The present invention is completed by results of molecular design for searching the material with the small polarizability of both electron polarization and atomic polarization.
If molecular polarizability a is defined as
&agr;=&agr; (electron polarization)+&agr; (atom polarization)
dipole-moment &mgr; of a molecule is given as a function of an electric field E and basic coordinate q of a molecule. The electron polarization and the atom polarization can be evaluated by differentiating the dipole moment &mgr; with the electric field E.
d
&mgr;(
E,q
)/
dE
=&dgr;&mgr;(
E,q
)/&dgr;
E
&dgr;&mgr; (
E,q
)/&dgr;
q&dgr;&mgr;/&dgr;E
&agr;(electron polarization)=&dgr;&mgr;(
E,q
)/&dgr;
E
α
(
atom
polarization
)
=
δ
μ
(
E
,
q
)
/
δ
q
δμ
/
δ
E
=
δ
μ
/
δ
q
(
δ
2
E
/
δ
q
δ
q
)
-
1
δ
Mikami Noboru
Nobutoki Hideharu
Tsunoda Sei
Chaudhuri Olik
Kielin Erik
Mitsubishi Denki & Kabushiki Kaisha
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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