JP3836553B2 - Method for manufacturing silicon insulating film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a gate insulating film such as a thin film transistor made of polycrystalline silicon or amorphous silicon, a silicon-based insulating film containing no hydrogen for forming an interlayer insulating film at a low temperature, or a liquid crystal display between an inexpensive glass film and a semiconductor element. The present invention relates to a method of manufacturing a silicon-based insulating film that does not contain hydrogen for interposing and protecting a semiconductor element.
[0002]
[Prior art]
The insulating film can be formed at a low temperature by decomposing and depositing silane with oxygen or nitrous oxide (N ₂ O) or by using tetraethylorthosilicate (mainly Si (OC ₂ H ₅ ) ₄ ) with ozone. Decomposition and deposition methods are used.
[0003]
[Problems to be solved by the invention]
In a semiconductor integrated circuit device or the like, when hydrogen is contained in a silicon oxide film or nitride film deposited as a gate oxide film or an interlayer insulating film (present as a compound such as Si—OH or Si—H), the hydrogen is integrated into the integrated circuit. It becomes a factor which makes the characteristic of an apparatus unstable. Or, in a liquid crystal display or the like, a semiconductor element is protected by an inexpensive glass film, but impurities contained in the glass film move to the semiconductor element and deteriorate characteristics, so that a high-purity insulating film is interposed between the glass film and the semiconductor element. Let If the insulating film contains hydrogen, the semiconductor element is deteriorated. Therefore, it is necessary to interpose a silicon-based insulating film not containing hydrogen for protecting the semiconductor element. Therefore, it is desired that the deposited film does not contain hydrogen. However, since the source gas contains hydrogen, it is difficult to prevent hydrogen from being contained in the deposited film.
[0004]
For example, tetra-isocyanate silane (Si (NCO) ₄ ) does not contain hydrogen, so that such an insulating film can be deposited in principle. Although this material is liquid at room temperature, its boiling point is as low as 186 ° C, so a sufficient vapor pressure can be obtained, so it can be easily supplied to the CVD reaction chamber, and is considered promising as a silicon dioxide film. . However, in order to deposit an insulating film by thermal decomposition using tetraisocyanate silane, about 1000 ° C. is required, so low temperature deposition cannot be performed.
[0005]
In addition, if a hydrolysis reaction of tetra-isocyanate-silane is used, low-temperature deposition is possible at about 400 ° C or less, but hydrogen in water is contained in the deposited insulating film and does not contain the target hydrogen. An insulating film cannot be obtained. Alternatively, tetra-isocyanate silane can be decomposed in plasma at a low temperature of about 400 ° C or less, but because of the use of plasma, the deposited insulating film and the interface are damaged, resulting in good film quality. Is difficult.
[0006]
In addition, tetraisocyanate silane has a strong dipole moment with N—C bonds in its structure, so it shows high reactivity with materials such as water and ammonia that contain the same dipole moment. It is known to form. Although it is possible to form an insulating film using this method, it is not possible to obtain a target insulating film that does not contain hydrogen because hydrogen is contained in water and ammonia because the hydrogen is contained in water and ammonia. Can not.
[0007]
An object of this invention is to provide the manufacturing method of the insulating film which can manufacture the silicon type insulating film which does not contain hydrogen easily.
[0008]
[Means for Solving the Problems]
In the present invention, a silicon-based insulating film is deposited on a substrate by reacting a silicon-based raw material not containing hydrogen with a mixed gas or liquid containing a tertiary amine.
[0009]
Since tertiary amines such as alkyl amines have a dipole moment, they react with tetraisocyanate silane at a low temperature to produce a silicon dioxide film or a silicon nitride film. Although hydrogen exists in this raw material, it is not decomposed at low temperature because it is bonded to carbon by a strong bonding force in the form of C—H. Therefore, the bond between the carbon and hydrogen is decomposed to generate a compound with other hydrogen (Si—OH, Si—H, etc.) and is hardly taken into the deposited film. In particular, if an amine in which hydrogen is replaced with a halogen such as fluorine or chlorine is used, a high-quality silicon-based insulating film that does not contain hydrogen can be deposited because no hydrogen is contained in the raw material.
[0010]
FIG. 1 is a diagram illustrating the principle of the present invention.
In FIG.
Reference numeral 1 denotes a reaction chamber which reacts a silicon-based raw material not containing hydrogen with a tertiary amine to deposit a silicon-based insulating film on the substrate 5.
[0011]
2 is a feed pipe A, and supplies the third kind amine (as the first three amines, for example, preparative Li trifluoromethyl-amine, tri-alkyl amines such as tri-trifluoroethyl-amine In which hydrogen is substituted with halogen).
[0012]
3 is a supply pipe B for supplying a silicon-based raw material having no hydrogen ( for example, silicon tetrachloride (SiCl ₄ ) Etc.) .
[0013]
4 is an exhaust pipe.
Reference numeral 5 denotes a substrate on which a silicon insulating film produced in the reaction chamber 1 is deposited.
[0014]
Reference numeral 6 denotes a silicon-based insulating film, which is a silicon-based insulating film (silicon dioxide, silicon nitride, etc.) on which a product obtained by reacting a silicon-based raw material not containing hydrogen with a tertiary amine is deposited.
[0015]
The silicon-based raw material not containing hydrogen and the tertiary amine are introduced directly into the reaction chamber by a gas or the liquid vapor is introduced into the reaction chamber using a carrier gas. Then, the tertiary amine supplied from the supply pipe A (2) and the silicon-based raw material not containing hydrogen supplied from the supply pipe B (3) react in the reaction chamber 1 to generate a silicon-based insulating material, A silicon insulating film 6 is obtained by being deposited on the substrate 5.
[0016]
7 is a reaction product.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2 shows an apparatus configuration of Example 1 of the present invention, which is a configuration of an atmospheric pressure hot wall type CVD apparatus. Directly introduced into the reaction chamber 1 a A amine-based gas by supply tube A (2), silicon-based raw material is obtained so as to introduce the vapor of tetra isocyanate silane of the liquid by a carrier gas (N _2). The deposition temperature is 200 ° C., which is a low temperature deposition.
[0018]
In FIG.
1 is a reaction chamber.
2 is a feed pipe A, a tube for introducing the amine-based gas such as preparative Li trifluoromethyl-amine.
[0019]
Reference numeral 3 denotes a supply pipe B for introducing a carrier gas (N ₂ ) for carrying tetra-isocyanate-silane vapor.
4 is an exhaust pipe.
[0020]
Reference numeral 5 denotes a substrate.
Reference numeral 11 denotes a flow rate control device for adjusting the flow rate of the amine-based gas.
A flow control device 12 is a pipe for adjusting the flow rate of the carrier gas carrying the tetraisocyanate silane vapor.
[0021]
Reference numerals 13 and 14 denote valves of the supply pipe A (2).
Reference numerals 15, 16, and 17 denote valves of the supply pipe B (3).
21 is a container for liquid tetraisocyanate silane.
[0022]
22 is liquid tetraisocyanate silane.
Reference numerals 23 and 24 denote heaters.
In the configuration of FIG. 2, the amine-based gas is directly introduced into the reaction chamber 1 through the supply pipe A (2). The flow rate is controlled by the flow rate control device 11. A carrier gas is introduced from the supply pipe B (3), passes through the liquid tetra-isocyanate-silane, and is introduced into the reaction chamber 1 together with the vapor of tetra-isocyanate-silane. The flow rate is controlled by the flow rate control device 11. In the reaction chamber 1, the amine-based gas reacts with the vapor of the silicon-based raw material and is thermally decomposed at normal pressure or reduced pressure, and a silicon dioxide film is deposited on the substrate 5. The deposition temperature is about 200 ° C. The gas in the reaction chamber 1 is exhausted through the exhaust pipe 4.
[0023]
FIG. 3 shows the configuration of an apparatus according to the second embodiment of the present invention, which is a configuration of an atmospheric pressure hot wall type CVD apparatus. It is obtained so as to introduce into the reaction chamber by preparative Li vapor at normal temperature of the liquid of the amine-based source such as fluoroethyl amine and the silicon-based precursor vapor to the carrier gas, respectively (N _2). The deposition temperature is 200 ° C., which is a low temperature deposition.
[0024]
In FIG.
1 is a reaction chamber.
Reference numeral 2 denotes a supply pipe A, which is a pipe for introducing a carrier gas (N ₂ ) that carries the amine-based raw material vapor.
[0025]
Reference numeral 3 denotes a supply pipe B which introduces a carrier gas carrying tetra-isocyanate-silane vapor.
4 is an exhaust pipe.
[0026]
Reference numeral 5 denotes a substrate.
Reference numeral 11 denotes a flow rate control device that adjusts the flow rate of the carrier gas that carries the vapor of the amine-based raw material.
[0027]
A liquid quantity control device 12 is a pipe for adjusting the flow rate of the carrier gas carrying the tetraisocyanate silane vapor.
Reference numerals 13, 14, and 15 denote valves of the supply pipe A (2).
[0028]
Reference numerals 16, 17, and 18 denote valves of the supply pipe B (3).
Reference numeral 21 denotes a container for storing a liquid amine material.
21 'is a container for liquid tetraisocyanate silane.
[0029]
22 is an amine starting material liquid at room temperature such as preparative Li trifluoroethyl-amine.
22 'is a liquid tetraisocyanate silane.
[0030]
Reference numerals 23 and 24 denote heaters.
3, the carrier gas is introduced from the supply pipe A (2), passes through the liquid amine raw material 22, and is introduced into the reaction chamber 1 together with the vapor of the amine raw material. The flow rate is controlled by the flow rate control device 11. A carrier gas is introduced from the supply pipe B (3), passes through the liquid tetra-isocyanate-silane, and is introduced into the reaction chamber 1 together with the vapor of tetra-isocyanate-silane. The flow rate is controlled by the flow rate control device 11. In the reaction chamber 1, the vapor of the amine-based material and the vapor of the silicon-based material react and are thermally decomposed at normal pressure or reduced pressure, and a silicon dioxide film not containing hydrogen is deposited on the substrate 5. The deposition temperature is about 200 ° C. The gas in the reaction chamber 1 is exhausted through the exhaust pipe 4.
[0031]
As described above, in the present invention, tetraisocyanate silane can be thermally decomposed at a low temperature of 200 ° C. or lower by utilizing the strong polarizability of alkyl-amine-based raw materials, and insulation of a high-quality silicon dioxide film or the like. A film can be deposited. In addition, since the C—H bond contained in the alkyl / amine system has a strong bonding force, its hydrogen is decomposed, and a Si—OH compound or a Si—H compound is not generated and contained in the insulating film. In particular, if a halogenated trialkylamine or perfluoroalkylamine in which hydrogen is completely substituted with halogen is used, hydrogen does not exist in the raw material, so that the deposited silicon-based insulating film also contains hydrogen. There is no.
[0032]
In the above embodiment, only tetra-isocyanate-silane was described as the silicon-based material, but silicon tetrachloride ( SiCl ₄ Even with other silicon compounds such as), a good insulating film can be deposited.
[0033]
4 and 5 show the deposition conditions and measurement results of the insulating film of the example of the present invention.
Fig. 4 (a) shows the measurement results of Fourier transform infrared spectroscopy of silicon dioxide deposited by pyrolysis using trimethylamine (TMA) gas and tetraisocyanate silane (TICS) vapor as source gases. .
[0034]
FIG. 4B shows the conditions for forming the deposited film. The deposition conditions were as follows: hot substrate CVD apparatus, substrate temperature 200 ° C., TMA flow rate 30 sccm, TICS carrier (N ₂ ) flow rate 30 sccm (total gas flow rate 0.02 sccm), N ₂ flow rate 240 sccm, pressure 760 Torr. The deposition rate is 13 nm / h.
[0035]
As shown in FIG. 4A, there is a strong absorption peak only at 1070 cm ⁻¹ due to Si—O, and there are no Si—OH and Si—H peaks. There is no peak due to NCO and H ₂ O. The absorption spectrum is almost the same as that of the thermal oxide film.
[0036]
FIG. 5 (a) shows the results of Auger electron spectroscopy measurement of the deposited film produced under the conditions of FIG. 4 (b). FIG. 5A shows that the ratio of Si and O in the deposited film SiO ₂ is 1: 2, which is less than the measurement limit (about 1 percent) of the C and N measuring apparatus.
[0037]
FIG. 5 (b) is an XPS spectrum. The spectrum separated for Si ⁴⁺ is shown as a dotted curve. The Si ⁴⁺ component is 98 percent high.
From the above measurement results, it is clear that the deposited film is a silicon dioxide thin film that has an ideal ratio of silicon and oxygen and hardly contains hydrogen.
[0038]
【The invention's effect】
According to the present invention, a good silicon-based insulating film can be deposited on a substrate at a low temperature. In particular, since the deposited silicon insulating film does not contain hydrogen, even if it is used in an integrated circuit device or the like, its characteristics are not impaired.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating the principle of the present invention.
FIG. 2 is a diagram showing a device configuration of Embodiment 1 of the present invention.
FIG. 3 is a diagram showing an apparatus configuration of Embodiment 2 of the present invention.
FIG. 4 is a diagram showing measurement results of an example of the present invention.
FIG. 5 is a diagram showing measurement results of an example of the present invention.
[Explanation of symbols]
1: Reaction chamber 2: Supply pipe A
3: Supply pipe B
4: Exhaust pipe 5: Substrate 6: Silicon-based insulating film 7: Reaction product

Claims (2)

A silicon-based insulating film characterized by depositing a silicon dioxide thin film on a substrate by introducing tetra-isocyanate-silane and a halogenated tri-alkylamine in which all hydrogen has been replaced with halogen into a reaction vessel and reacting them. Manufacturing method. A method for producing a silicon-based insulating film, comprising introducing tetra-isocyanate-silane and perfluoroalkyl-amine into a reaction vessel, causing them to react, and depositing a silicon dioxide thin film on the substrate .

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