JP2758247B2 - Organic metal gas thin film forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to metal atoms used for wiring, electrodes, barrier metals, etc. of high-density integrated circuits, and Si, Ga used for capacitors, insulators, etc. The present invention relates to an organic metal-based thin film forming apparatus that forms a high-quality thin film by depositing semiconductor atoms such as a low-temperature process with good controllability.

[Conventional technology]

In order to realize a high-density integrated circuit, there is a strong demand for a method for producing a high-quality thin film at a low temperature in order to avoid adverse effects on the device due to heat and impurities mixed in the thin film. As a new technology responding to this, a chemical vapor deposition (CVD) method using an organic metal gas which forms a thin film by decomposition deposition at a relatively low temperature has been proposed. This technique has an excellent feature that a gas is decomposed at a relatively low temperature, so that a high-quality conductor, derivative, or insulator thin film can be manufactured even at a low temperature.

Generally, in the thin film formation by the CVD method, when the substrate temperature is increased, the quality of the formed film is improved, and the adhesion to the substrate is also increased. However, when a thin film is formed on a substrate by thermally decomposing an organic metal gas by heating with a heater, the ambient temperature rises following the substrate temperature. As a result, the organometallic gas itself is decomposed in the gas phase, and impurities such as carbides and oxides are formed by a subsequent secondary reaction. Therefore, a structure necessary for producing high-quality conductors, derivatives and insulator thin films. There is a problem that atoms cannot be supplied and deposited on a substrate without containing impurities. In addition, even in the formation of a thin film utilizing the excited decomposition of an organometallic gas in a gas phase, heater heating or substrate heating by another energy source is used in combination to improve the quality of the deposited film.
Since process control was not performed in consideration of the properties of the organometallic gas, it was difficult to produce a high-quality thin film using the organometallic gas.

For example, Fig. 2 shows Present and Future Materials of Taki et al.
FIG. 2 is a configuration diagram showing a conventional photoexcited thin film forming apparatus using an organometallic gas utilizing photoexcitation action by heater heating and laser irradiation described in the paper of Processing (1990) P206-P210. In the figure, 1 is a carrier gas for transferring a film forming gas, 2 is a reaction chamber in which a thin film is formed, 3 is a supply tank for the film forming gas, 5 is a mass flow controller for controlling the supply amount of the film forming gas, Reference numeral 8 denotes a supply port of a film forming gas to the reaction chamber 2, 9 denotes a substrate on which a thin film is to be formed, 10 denotes a susceptor with a heater for heating the substrate 9, 11 denotes a vacuum pump for exhausting the reaction chamber 2, 12 Is a vacuum pump 11
, An ultraviolet laser oscillator 19, an ultraviolet laser beam 20 emitted from the ultraviolet laser oscillator 19, and an ultraviolet laser beam 20
Is a cylindrical telescope for shaping the film into the energy density necessary for dissociating the film forming gas.
A window 23 for introducing the ultraviolet laser beam 20 into the reaction chamber 2 while shutting off the film forming gas atmosphere and the atmosphere therein, and a window 23 for controlling deposition of a decomposition product on the window 22 due to decomposition of the film forming gas. A purge gas supply port 24 is a mass flow controller that controls the supply amount of the purge gas.

 Next, the operation will be described.

Ultraviolet laser light 20 emitted from an ultraviolet laser oscillator 19
Is shaped by a cylindrical telescope 21 to have an energy density equal to or higher than the energy density required for dissociating the film-forming gas, and is introduced into the reaction chamber 2 through the window 22. The ultraviolet laser light 20 is
By changing the direction of the susceptor 10 with a heater, the substrate 9 is irradiated in parallel or perpendicularly.

When only the thermal decomposition by the heater is used, the organic metal gas is heated on the substrate 9 to be decomposed and deposited to form a thin film. In the prior art, in order to obtain a high-quality and strong adhesive film, the susceptor 10 with a heater is used to increase the decomposition rate of organometallic gas on the surface of the substrate 9 and the migration effect of deposits. 9 was to be heated. Further, when utilizing the excited decomposition of the organometallic gas in the gas phase by light excitation, the excited species formed in the gas phase are deposited on the substrate 9 by diffusion to form a thin film. Without heating, a high-quality thin film with strong adhesive force cannot be obtained.
Was used in combination. In this case, the problem that the ambient temperature rises due to the rise in the temperature of the substrate 9 and thus impurities such as carbides are formed in the gas phase and mixed into the film has been neglected. That is, when the temperature of the substrate 9 is increased by heater heating, laser irradiation heating, or the like to improve the film quality, the ambient temperature is increased accordingly, and when the temperature exceeds a certain temperature, carbides or oxidized atoms of atoms constituting the organometallic gas are formed. Impurities such as substances are formed in the gas phase. In the conventional technology, the ambient temperature rises by raising the heater temperature to improve the film quality described above. Even if impurities such as carbides are generated in the gas phase, the ambient temperature cannot be controlled or the generation of impurities is controlled. Since the process for performing this process was not included in the apparatus, there was no method for avoiding contamination of the film with impurities.

[Problems to be solved by the invention]

Since the conventional organic metal gas utilizing thin film forming apparatus is configured as described above, the organic metal gas causes thermal decomposition by heater heating or excitation decomposition by photon energy or the like in the atmosphere on the substrate 9, and Since there is no concept of controlling impurities such as a precursor which forms a thin film by adsorption and a carbide generated by a secondary reaction thereof, there has been no way to avoid contamination of the film with impurities.
In addition, in order to improve the quality of the film in which the organometallic gas is diffused and deposited on the substrate 9, a method of further heating the substrate 9 at the expense of lowering the temperature for forming the thin film to some extent is also used. In such a case, impurities such as carbides are further generated by the secondary reaction, and there is a problem that it is difficult to produce a high-quality thin film.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and controls the atmosphere on a substrate by using an organic metal gas that can be decomposed at a low temperature, thereby reducing the environment in the gas phase to an impurity caused by a secondary reaction. It is an object of the present invention to obtain a thin film forming apparatus using an organometallic gas, which can obtain expected film quality by depositing and reforming a thin film while maintaining the state without generation.

[Means for solving the problem]

An apparatus for forming a thin film using an organic metal gas according to the present invention comprises a first substrate heating device for decomposing and depositing an organic metal gas, and a monitor device for monitoring at least one of generation of impurities in the reaction chamber and substrate ambient temperature. And a reaction control device for controlling the operation of the first substrate heating device according to the monitor of the monitor device.

According to a second aspect of the present invention, there is provided a thin film forming apparatus utilizing an organic metal gas, wherein a second substrate heating device for heating a surface layer of a substrate is added to the first aspect of the present invention. The supply of the organic metal gas and the control of the second substrate heating device are performed so that the heating by the second substrate heating device and the heating by the second substrate heating device are alternately performed.

The thin film forming apparatus utilizing an organic metal gas according to the third aspect of the present invention uses a carbonyl-based organic metal gas as the organic metal gas and controls the operation of the first substrate heating apparatus so that the substrate atmosphere temperature is 400 ° C. or lower. It is provided with a reaction control device.

According to a fourth aspect of the present invention, there is provided a thin film forming apparatus utilizing an organic metal gas, wherein a second substrate heating device for heating a surface layer of a substrate is added to the third aspect of the present invention, and a carbonyl-based organic metal gas is formed by a reaction control device. The supply of the carbonyl-based organometallic gas and the control of the second substrate heating device are performed so that the supply and the heating by the second substrate heating device are alternated.

(Operation)

The organometallic gas utilizing thin film forming apparatus in the present invention,
Organometallic gas decomposition system that decomposes organic metal gas on the substrate or in the gas phase to deposit a thin film, thin film reforming system that heats only the substrate surface to improve the quality of the deposited thin film, and secondary in the gas phase The reaction control system monitors impurities such as carbides formed as a result of the reaction and controls the reaction.

In an organic metal gas decomposition system, an organic metal gas is decomposed and deposited on a substrate surface or in a gas phase by energy of heat, light, or electrons. In this case, the reaction control system is used to generate heat, light and gas under a condition in which a gas that inactivates the dissociated molecules or lowers the reactivity is flown under an atmosphere temperature, energy intensity and pressure condition in which impurities such as carbides due to the dissociated molecules are not generated. An energy source such as electrons acts. As a result, in a state where impurities such as carbides generated by the secondary reaction are not generated,
Since excited species having few or no impurity atoms constituting the organometallic gas can be used as a precursor for substrate adsorption, a thin film containing no atoms constituting the organometallic gas such as carbon as impurities can be produced. Further, a high-quality thin film having strong adhesive force can be realized by using the substrate surface heating by the thin-film reforming system in a state where generation of impurities in the gas phase is controlled by the control system. As described above, by maintaining the reaction control system in a state where no impurities are generated, and using the organometallic gas decomposition system and the thin film reforming system alternately to obtain a high adhesion thin film of expected quality Becomes possible.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing an organic metal gas utilizing thin film forming apparatus according to Embodiments 1 and 2 of the present invention, wherein W (CO) ₆ [tungsten carbonyl] is used as the organic metal gas.
Here, a case in which the production between high-purity W by the CVD method using the method is targeted. In the figure, 1, 2, 3, 9, 10, 11, and 12 correspond to the same reference numerals in FIG.

In FIG. 1, reference numeral 4 denotes an automatic opening / closing valve for controlling the supply of the carrier gas 1 and the organic metal gas, and reference numeral 7 denotes a reaction control device for performing overall control. In this embodiment, a CVD control device 7 is used.
Is used. 6 is a pressure regulator controlled by a CVD controller 7, 10 is a susceptor with a heater as a first substrate heating device for thermally decomposing an organic metal gas, and 13 is for measuring the temperature of the substrate 9 and the ambient temperature. Is a power supply device for controlling the CVD controller 7 to supply power to the susceptor 10 with a heater. Reference numeral 15 is a second substrate heating device for reforming a thin film provided in the reaction chamber 2. 9 is heated. 16 is a quadrupole gravimetric analyzer for detecting the generation of impurities such as carbides in the reaction chamber 2,
17 is a monitoring device for impurities and temperature, 18 is a power supply device for supplying power to the second substrate heating device 15 controlled by the CVD control device 7, and 25 is a device for transferring heat of the second substrate heating device 15 to the reaction chamber. It is a window to introduce.

 Next, the operation of the first embodiment will be described.

Organometallic gas W (CO) supplied into the reaction chamber 2
₆ is a thermal decomposition by a heater, an excitation decomposition by a laser beam or an electron beam or the like having an appropriate energy density or a wavelength for decomposition of an organic metal gas, or a combination of heating and excitation decomposition by a heater. Next, a W film is formed.

Here, a method using only heater heating by a susceptor 10 with a heater as an energy source for decomposing an organic metal gas and depositing a thin film on the substrate 9 will be described as an example.

The substrate 9 is heated by the susceptor 10 with the heater, and the organic metal gas does not form impurities such as carbides in the gas phase.
It is heated to a temperature at which a thin film can be formed by decomposition and deposition. This heating is performed according to the detection by the quadrupole gravimetric analyzer 16 or according to the ambient temperature on the substrate 9. In this case,
The pressure in the reaction chamber 2 is controlled by the pressure adjusting device 6 and the gas supply amount is controlled by the mass flow controller 5 by the CVD control device 7. In this way, it is possible to avoid formation of impurities such as W carbide and W oxide caused by atoms constituting the organometallic gas.

For example, under the condition that the atmospheric temperature on the substrate 9 is 400 ° C. or more, impurities such as W carbide and W oxide are generated. Therefore, only the precursor necessary for film formation is supplied on the surface of the substrate 9 alone. It becomes impossible. Therefore, the susceptor with heater 10 is controlled so that the ambient temperature on the substrate 9 is 400 ° C. or less. At this time, the organometallic gas W (CO) ₆
In a state where impurities are not generated, the ligand CO is dissociated by heating the atmosphere by the effect of heating the substrate 9. As a result, undecomposed W (CO) ₆ , which is a precursor to be adsorbed on the substrate 9 to form a thin film, or excited species W (CO)
Only X (X = 0 to 5) can be supplied onto the substrate 9. This excited species has a smaller ratio of C and O, which cause impurity atoms, in its constituent molecules than the film-forming gas W (CO) ₆ . The generation of impurities can be suppressed by using a general He gas as the carrier gas 1 and reducing the pressure to less than 2 Torr.

Examples of the carrier gas 1 include an inert gas such as He that reduces the concentration of dissociated excited species and reduces the reactivity between excited species, or H ₂ and Cl ₂ , HC that reduce and inactivate dissociated ligands.
A halogen-based gas such as l or a mixed gas of the above is suitable.

As described above, according to this embodiment, the CVD controller 7
Controls the susceptor with heater 10 so that the undecomposed organometallic gas or its excited species necessary for producing a high-quality thin film at a low temperature can be removed from the substrate 9 without generating impurities such as carbides.
Can be supplied on the surface of the substrate and decomposed and deposited.

In this embodiment, the organic metal gas is decomposed and the substrate 9 is decomposed.
As a first substrate heating device for depositing a thin film thereon, a method using heating by a susceptor with a heater 10 has been described. However, laser light in the absorption wavelength range of the substrate 9 is used as a source of energy other than heater heating. It is effective to use the lamp light heating device alone or in combination with the heater heating. Further, a substrate heating source such as an electron beam and an ion beam may be used. Further, only the surface of the substrate 9 is instantaneously heated selectively by pulse heating using laser light or the like which does not absorb by the organometallic gas to reduce the amount of heat transfer into the gas phase,
Further, the pressure is reduced by the pressure adjusting device 6 to suppress the heat transfer of the gas temperature in the gas phase, so that the excited species supplied into the reaction chamber 2 is further decomposed to generate W.
Impurities such as carbides can be avoided, and a higher quality thin film can be formed.

Further, there is a method using decomposition deposition by light excitation, electron beam excitation, ion beam excitation, or the like. When photolysis by light irradiation is applied as a method of excitation, W (CO) ₆
Since the absorption wavelength of light is in the region of about 300 nm or less,
It is necessary to use light in this region. By pulsing the light irradiation, the amount of excited species generated can be precisely controlled. When utilizing the effect of thermal decomposition by light irradiation, the energy density is 1 W regardless of the wavelength or the above.
/ cm ² or more. Also at this time, the pulsed laser enables precise control of the amount of excited species generated. This is also true when using electron beams or ion beams. The excited species formed at this time are diffused and deposited on the substrate 9 without increasing the temperature of the substrate 9, but also use heater heating while monitoring the generation of impurities such as W carbide and the ambient temperature on the substrate 9. Then, a high-quality film can be formed with good controllability.

 Next, the operation of the second embodiment will be described.

Substrate 9 for producing high quality and high adhesion thin film
In the case where an organic metal gas is used, when the ambient temperature rises above a certain temperature, impurities such as W carbide are generated. For example, in the case of W (CO) ₆ , this state occurs when the ambient temperature is 400 ° C. or higher. For this reason, the substrate 9 having a temperature equal to or higher than this temperature while the organic metal gas is flowing is
If the deposition and the modification of the thin film are performed simultaneously by heating, impurities are mixed in the film, and a truly high-quality thin film cannot be produced.

Here, only heater heating by a susceptor 10 with a heater is used as an energy source for decomposing an organic metal gas and depositing a thin film on the substrate 9, and the deposited thin film is heated to a high quality thin film having a strong adhesive force to the substrate 9. A method using the second substrate heating device 15 using lamp light heating as a heat source for reforming will be described as an example.

The W deposition and the reforming are alternately performed instead of simultaneously, and the control is performed by synchronizing the deposition with the gas supply and forming a pulse. The thin film is deposited by the method described in the first embodiment. Modification of thin film
The supply of the organic metal gas is stopped, and the surface layer of the substrate 9 is heated by the second substrate heating device 15. In this manner, a W film with higher quality and higher adhesion is obtained.

Also in this embodiment, it is effective to use laser light and lamp light heating in the absorption wavelength region of the substrate 9 alone or in combination with heater heating as the second substrate heating device 15 for modifying the thin film in addition to heater heating. . Further, it is more effective to selectively heat only the surface of the substrate 9 instantaneously by pulse heating using laser light having a wavelength not absorbed by the organometallic gas. Further, a substrate heating source such as an electron beam and an ion beam may be used.

As described above, according to this example, for the film and the modification,
By controlling the supply of the susceptor 10 with the heater and the supply of the gas by the CVD control device 7 and the heating by the second substrate heating device 15, the decomposition deposition of the organometallic gas and the reforming thereof are performed alternately.
A high-quality, high-adhesion thin film can be produced.

〔The invention's effect〕

As described above, according to the first aspect of the present invention, a first substrate heating device for decomposing and depositing an organometallic gas, a monitor device for monitoring at least one of generation of impurities in a reaction chamber and a substrate ambient temperature, A reaction control device for controlling the operation of the first substrate heating device according to the monitor of the monitor device is provided, so that the film forming precursor does not contain impurities such as carbides generated by a secondary reaction. ,
Since a film-forming precursor having few or no impurity atoms constituting the organic metal gas remaining in the film can be used, a thin film containing no atoms constituting the organic metal gas such as carbon as impurities can be produced. is there.

According to the second aspect of the present invention, a second substrate heating device for heating the surface layer of the substrate is added to the first aspect of the present invention, and the organic metal gas supply and the second substrate heating device are performed by the reaction control device. Since the configuration is such that the supply of the organometallic gas and the second substrate heating device are controlled so that heating and heating are alternated,
In addition to the effect of the first aspect, there is an effect that the produced film has high crystallinity and high adhesion to the substrate.

According to the invention of claim 3, a reaction control device that controls the operation of the first substrate heating device so that the substrate atmosphere temperature is 400 ° C. or less using a carbonyl-based organometallic gas as the organometallic gas is provided. Because of this configuration, by using a carbonyl-based organometallic gas, it is possible to reduce the first substrate atmosphere temperature to 400 ° C. or less without directly measuring impurities such as carbides generated by a secondary reaction in the film forming precursor.
By simply controlling the operation of the substrate heating apparatus described above, there is an effect that a thin film containing no atoms constituting an organic metal gas such as carbon as impurities can be produced.

According to the fourth aspect of the present invention, a second substrate heating device for heating the surface layer of the substrate is added to the third aspect of the present invention, and the supply of the carbonyl-based organometallic gas and the second substrate heating are performed by the reaction control device. Since the supply of the carbonyl-based organometallic gas and the control of the second substrate heating device are controlled so that the heating by the device is alternated, in addition to the effect of claim 3, the produced film has crystallinity and substrate. This has the effect of having a high adhesive force with the adhesive.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an organic metal gas utilizing thin film forming apparatus according to Embodiments 1 and 2 of the present invention, and FIG. 2 is a configuration diagram showing a conventional photoexcited thin film forming apparatus utilizing an organic metal gas. 2 is a reaction chamber, 3 is an organic metal gas supply tank, 7 is CV
D controller, 9 is a substrate, 10 is a susceptor with a heater, 13 is a temperature measuring terminal, 15 is a second substrate heating device, and 16 is a quadrupole gravimetric analyzer. In the drawings, the same reference numerals indicate the same or corresponding parts.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C23C 16/00-16/56 H01L 21/205 H01L 21/285

Claims (4)

(57) [Claims] A first substrate heating device for decomposing and depositing the organometallic gas, wherein the organometallic gas is decomposed in a reaction chamber to deposit a film on the substrate; A monitor device for monitoring at least one of generation of impurities in the chamber or the substrate ambient temperature, and a reaction control device for controlling the operation of the first substrate heating device according to the monitor of the monitor device. A thin film forming apparatus utilizing an organometallic gas. 2. A thin film forming apparatus utilizing an organic metal gas which decomposes an organic metal gas in a reaction chamber to deposit a film on a substrate, comprising: a first substrate heating device for decomposing and depositing the organic metal gas; A second substrate heating device for heating the surface layer of the above, a monitor device for monitoring at least one of the generation of impurities in the reaction chamber and the substrate ambient temperature, and the first device according to the monitor of the monitor device. Reaction for controlling the operation of the substrate heating device and controlling the supply of the organic metal gas and the control of the second substrate heating device so that the supply of the organic metal gas and the heating by the second substrate heating device are alternated. An organic metal gas utilizing thin film forming apparatus, comprising: a control device. 3. A first substrate heating device for decomposing and depositing a carbonyl-based organic metal gas in a thin-film forming apparatus utilizing an organic-metal gas in which a carbonyl-based organic metal gas is decomposed in a reaction chamber to deposit a film on a substrate. And a reaction control device for controlling the operation of the first substrate heating device so that the substrate ambient temperature is 400 ° C. or less. 4. A first substrate heating apparatus for decomposing and depositing a carbonyl-based organic metal gas in a thin-film forming apparatus utilizing an organic-metal gas in which a carbonyl-based organic metal gas is decomposed in a reaction chamber to deposit a film on a substrate. A second substrate heating device for heating the surface layer of the substrate, a monitor device for monitoring at least one of generation of impurities in the reaction chamber or the substrate ambient temperature, and a substrate ambient temperature of 400 ° C. or less. Controlling the operation of the first substrate heating apparatus so that the supply of the carbonyl-based organic metal gas and the supply of the carbonyl-based organic metal gas and the heating by the second substrate heating apparatus are alternately performed. An apparatus for forming a thin film using an organometallic gas, comprising: a reaction control device for controlling a second substrate heating device.