Patent Application
20150361550
This application claims the benefit of Japanese Patent Application No. 2014-123514, filed on Jun. 16, 2014, in the Japan Patent Office, the disclosure of which is incorporated herein in its entirety by reference.
The present disclosure relates to a film formation apparatus and method for forming an oxide film on a substrate in a vacuum atmosphere, and a non-transitory computer readable storage medium used in the film formation method and apparatus.
In the manufacture process of semiconductor devices, a process for oxidizing a surface of a semiconductor wafer (hereinafter also referred to as a ┌wafer┘), that is, a substrate, may be performed on the semiconductor wafer. A technology for performing the oxidation is disclosed.
For example, atomic layer deposition (ALD) has been known as a process for performing oxidation. Processing for forming a thin film, such as a silicon oxide (SiO2) film, on a surface of a wafer using ALD may be performed. In a film formation apparatus for performing the ALD, the mounting unit for loading a wafer thereon is installed in a processing chamber (vacuum chamber) the inside of which is under a vacuum atmosphere. Furthermore, the supply of a raw material gas including a silicon raw material and the oxidization of the raw material adsorbed to the wafer are alternately repeated on the loaded wafer several times.
The oxidization of the raw material is performed by supplying an oxidizing gas, such as oxygen or ozone, to the wafer or supplying hydrogen and oxygen to the wafer so that oxygen radicals are generated or plasma is formed with oxygen within the vacuum chamber. However, when the oxidizing gas is supplied, the wafer needs to be heated at a relatively high temperature in order for the oxidizing gas to chemically react with the raw material. Further, when the oxygen radicals are generated, in order to generate the radicals, the wafer needs to be heated at a relatively high temperature. When the oxygen plasma is used, components of the raw material gas accumulated in the wafer may be oxidized even at room temperature. However, film quality becomes different between a planar section and a lateral section of a pattern of the wafer due to straightness of plasma active species formed of ions or electrons, thereby making the film quality of the lateral section poorer than the film quality of the planar section. For this reason, it is difficult to apply such an oxygen plasma when forming a fine pattern.
For this reason, in the related art, a heating unit, such as a heater, is installed in a film formation apparatus. However, when the heating unit is installed as described above, the manufacture cost or operation cost of the film formation apparatus is increased. Further, when the heating unit is installed as described above, it is difficult to reduce a processing time because the raw material is not oxidized until the wafer is heated up to a specific temperature after the wafer is carried into the vacuum chamber. A technology is known in the related art in which the oxidation is performed at room temperature. However, in such a technology, a pressure rises suddenly in a processing space within the processing chamber due to a chain decomposition reaction when oxidation is performed. Specifically, the pressure within the processing space is increased to 20 to 30 times the pressure prior to the chain decomposition reaction. Accordingly, it is difficult to apply such a technology to an actual film formation apparatus. Further, in the related art, it is known that reactive species (atomic oxygen) are generated by supplying an oxygen gas, a nitrogen gas, and a hydrogen gas under reduced-pressure atmosphere and mixing the gases. However, the manufacture cost or operation cost of the film formation apparatus is increased, because temperature of the atmosphere under which each gas is supplied becomes 400 to 1200 degrees C. through heating by the heater in order to generate the atomic oxygen.
Embodiments of the present disclosure provide a technology capable of obtaining an oxide film of good properties and preventing an excessive rise of pressure within a processing space by sufficiently performing an oxidation without using a heating unit for heating a substrate in forming the oxide film in the substrate by repeating a cycle including: adsorption of raw material to the substrate; and oxidization of the raw material.
According to an embodiment of the present disclosure, a film formation apparatus configured to obtain a thin film by stacking a molecule layer of oxide on a surface of a substrate loaded onto a table under a vacuum atmosphere formed within a vacuum chamber is provided. The film formation apparatus includes: a rotation unit configured to repeat alternately placing the substrate in a first region and a second region disposed in a circumference direction of the table over the table by rotating the table with respect to the first region and the second region; a raw material gas supply unit configured to supply the first region with a raw material in a gaseous state as a raw material gas so that the raw material is adsorbed to the substrate; a processing space formation member configured to move up and down with respect to the table in order to form a processing space near the substrate placed in the second region, the processing space being isolated from the first region; an atmosphere gas supply unit configured to supply an atmosphere gas for forming an ozone atmosphere including ozone of a concentration that is equal to or higher than a concentration at which a chain decomposition reaction is generated in the processing space; an energy supply unit configured to forcibly decompose the ozone by supplying energy to the ozone atmosphere so that active species of oxygen are generated and to obtain the oxide by oxidizing the raw material adsorbed to a surface of the substrate by the active species; a buffer region configured to be connected to the processing space in order to reduce a rise of pressure in the processing space attributable to the decomposition of the ozone, the buffer region being supplied with an inert gas; and a partition unit configured to partition the buffer region from the processing space when the atmosphere gas is supplied to the processing space and to have the buffer region communicate with the processing space when the decomposition of the ozone is generated.
According to another embodiment of the present disclosure, a film formation method for obtaining a thin film by stacking a molecule layer of oxide on a surface of a substrate loaded onto a table under a vacuum atmosphere formed within a vacuum chamber is provided. The film formation method includes: repeating to alternately place the substrate in a first region and second region disposed in a circumference direction of the table over the table by rotating the table with respect to the first region and the second region; supplying the first region with a raw material in a gaseous state as a raw material gas so that the raw material is adsorbed to the substrate; moving a processing space formation member up and down with respect to the table in order to form a processing space near the substrate placed in the second region, the processing space being isolated from the first region; supplying an atmosphere gas for forming an ozone atmosphere including ozone of a concentration that is equal to or higher than a concentration at which a chain decomposition reaction is generated in the processing space; forcibly decomposing the ozone by supplying energy to the ozone atmosphere so that active species of oxygen are generated, and obtaining the oxide by oxidizing the raw material adsorbed to a surface of the substrate by the active species; supplying an inert gas to a buffer region formed to reduce a rise of pressure in the processing space attributable to the decomposition of the ozone; and partitioning the buffer region from the processing space when the atmosphere gas is supplied to the processing space, and having the buffer region communicate with the processing space when the decomposition of the ozone is generated.
According to another embodiment of the present disclosure, a non-transitory computer-readable storage medium in which a computer program used in a film formation apparatus configured to obtain a thin film by stacking a molecule layer of oxide on a surface of a substrate under a vacuum atmosphere formed within a vacuum chamber has been stored, wherein the computer program includes steps organized so as to execute the film formation method.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.
Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments.
A film formation apparatus 1 in accordance with a first embodiment of the present disclosure is described with reference to
The rotary table 12 that is horizontal and circular is provided in the vacuum chamber 11 and rotated in its circumferential direction by a rotation mechanism 13 in its circumference direction. In this example, as indicated by arrows in
Exhaust ports 17, 18 are opened at the bottom of the vacuum chamber 11 outside the rotary table 12. One end of an exhaust pipe 21 is connected to each of the exhaust ports 17 and 18. The other end of the exhaust pipe 21 is connected to an exhaust mechanism 23 via an exhaust amount adjustment unit 22. The exhaust mechanism 23 may be formed of a vacuum pump, for example. The exhaust amount adjustment unit 22 may include a value. Further, the exhaust amount adjustment unit 22, for example, adjusts an exhaust flow rate from the exhaust ports 17 and 18, and maintains the inside of the vacuum chamber 11 under a vacuum atmosphere of a predetermined pressure.
In
As illustrated in
The gas shower heads 3A and 3B are raw material gas supply units and likewise configured. The gas shower head 3A illustrated in
The aminosilane gas supply source 35 forcibly supplies aminosilane (an aminosilane gas) which is a film formation raw material in a gaseous state, to the diffusion space 33 through the gas supply pipe 34 in response to a control signal from a control unit 10, which will be described below. Any gas that may be adsorbed to the wafer W and oxidized to form a silicon oxide film may be used as the aminosilane gas. In this example, a bis(tert-butylamino)silane (BTBAS) gas is supplied as the aminosilane gas. Regions (i.e., first regions) under the shower head bodies 31 of the gas shower heads 3A and 3B over the rotary table 12 are aminosilane adsorption regions 30A and 30B.
The purge gas nozzles 4A and 4B are likewise configured and extend in a diameter direction of the rotary table 12. As illustrated in
The hoods 5A and 5B are described below. The hoods 5A and 5B are configured similarly. The hood 5A of
The hood 5A is described below with reference to a longitudinal-section side view and a lower side perspective view of
For example, a plurality of openings 61 is opened at an interval along the circumferential direction of the main body portion 51 outside the processing space 54 under the main body portion 51. Each of the openings 61 is connected to a buffer region 62 formed over the processing space 54 in the main body portion 51. The buffer region 62 has a flat ring shape that surrounds the gas supply path 55. One end of a gas supply path 63 is opened in the buffer region 62. The other end of the gas supply path 63 extends upward along the passage formation portion 52, and is connected to a downstream end of a gas supply pipe 64 provided outside the vacuum chamber 11. An upstream end of the gas supply pipe 64 is connected to an argon (Ar) gas supply source 59 through a valve V3. Each of the Ar gas supply source 59, the O3 gas supply source 57, and the nitrogen monoxide (NO) gas supply source 58 is configured to forcibly supply a gas toward a downstream end of the gas supply pipe in response to a control signal from the control unit 10 which will be described below.
Further, one end of an exhaust path 65 is opened in the buffer region 62. The other end of the exhaust path 65 extends upward along the passage formation portion 52, and is connected to an upstream end of an exhaust pipe 66 provided outside the vacuum chamber 11. A downstream end of the exhaust pipe 66 is connected to the exhaust mechanism 23 through the exhaust amount adjustment unit 67 configured in the same manner as the exhaust amount adjustment unit 22. An exhaust amount of the buffer region 62 is controlled by the exhaust amount adjustment unit 67. Further, as illustrated in
An annular-shaped protrusion 68 protruded downward is formed in the main body portion 51. The protrusion 68 is formed to surround the opening 61 and the processing space 54. When the main body portion 51 moves down, the protrusion 68 is engaged with the groove 16 of the rotary table 12 so that the processing space 54 can be airtightly maintained. In the figures, the numeral “69” is a bottom surface inside the protrusion 68 of the main body portion 51. Further, for convenience of description, the outside of the processing space 54 within the vacuum chamber 11 may be described as an adsorption space 60 where the adsorption of aminosilane is performed.
The O3 gas supply source 57 as an atmosphere gas supply unit is further described below. For example, the O3 gas supply source 57 is configured to supply an O3 gas having a ratio of 8 to 100 Vol. % to oxygen to the processing space 54. As will be described below in detail, in the embodiment, ozone is decomposed by supplying an NO gas in the state while the processing space 54 into which the wafer W is carried is maintained under an ozone atmosphere. Such a decomposition is a forcibly generated chain decomposition reaction where ozone is decomposed by NO to generate active species, such as oxygen radicals, and the active species decompose ambient ozone to further generate the active species of oxygen. In other words, when the NO gas is supplied to the processing space 54, in the pressure of the processing space 54, O3 of a concentration equal to or higher than a concentration at which the chain decomposition reaction occurs needs to be present in the processing space 54. In order to form such an atmosphere in the processing space 54, the O3 gas is supplied from the O3 gas supply source 57.
The film formation apparatus 1 includes the control unit 10. For example, the control unit 10 includes a computer including a CPU and a memory unit (not illustrated). The control unit 10 sends a control signal to each element of the film formation apparatus 1 for controlling each of operations, such as opening/closing of each valve V, adjusting an exhaust flow rate by the exhaust amount adjustment units 22 and 67, supplying a gas from each gas supply source to each gas supply pipe, lifting of the lifting pins 26 by the lifting mechanism 27, rotating the rotary table 12 by the rotation mechanism 13, and lifting of the hoods 5A and 5B by the hood lifting mechanism 53. Further, in order to output such a control signal, a program formed of a group of steps (or commands) is stored in the memory unit. The program may be stored in a storage medium, such as, a hard disk, a compact disk, a magnet optical disk, or a memory card and installed in the computer.
Processes performed by the film formation apparatus 1 are schematically described below. When the rotary table 12 is rotated, the wafer W sequentially and repeatedly moves through the aminosilane adsorption region 30A, the purge region 40A, a region in which the processing space 54 is formed by the hood 5A, the aminosilane adsorption region 30B, the purge region 40B, and a region in which the processing space 54 is formed by the hood 5B. Assuming a cycle including adsorbing the aminosilane to the wafer W, purging the excessive aminosilane on the surface of the wafer W, and oxidizing the aminosilane (i.e., the formation of a silicon oxide layer) adsorbed to the wafer W form a single cycle, the cycle is repeatedly performed a plurality number of times as the wafer W moves through the regions as described above. Thus, the silicon oxide layer is stacked on the wafer W to form a silicon oxide film.
The hoods 5A and 5B likewise perform the oxidation of aminosilane. A process of oxidizing aminosilane by the hood 5A is described below with reference to
When the rotary table 12 is rotated and thus the wafer W moved from the purge region 40A is placed under the main body portion 51 of the hood 5A, the rotation of the rotary table 12 is stopped. At this time, each of the valves V1 to V3 of the hood 5A is closed. Further, the exhaust of the buffer region 62 by the exhaust amount adjustment unit 67 is stopped. After the rotation of the rotary table 12 is stopped, the main body portion 51 moves down. Thus, the protrusion 68 enters the groove 16 of the rotary table 12, and is engaged with the groove 16. Accordingly, the processing space 54 of the main body portion 51 becomes airtight, while being isolated from the adsorption space 60. When the main body portion 51 further moves down, the bottom 69 of the main body portion 51 is closely attached to the surface of the rotary table 12 such that the processing space 54 is partitioned from the buffer region 62 (Step S1 of
Thereafter, the valve V1 is opened, an O3 gas is supplied to the gas supply path 55 and the processing space 54, and an O3 concentration in the gas supply path 55 and the processing space 54 increases. The valve V3 is opened and an Ar gas is supplied to the buffer region 62 simultaneously with the supply of the O3 gas, and the buffer region 62 is exhausted by the exhaust amount adjustment unit 67 (Step S2 of
Thereafter, when the main body portion 51 slightly moves up and the bottom 69 of the main body portion 51 rises from the surface of the rotary table 12, a gap is formed. The processing space 54 communicates with the buffer region 62 through the gap (Step S3 of
Thereafter, when the valve V2 is opened, an NO gas is supplied to the gas supply path 55. The supplied NO gas comes in contact with O3 in the gas supply path 55, thereby igniting O3. As a result, a forcible decomposition reaction (i.e., a combustion reaction) of O3 is generated as already described. Chain decomposition proceeds within a region ranging from the gas supply path 55 to the processing space 54 within a very short time, thus generating active species of oxygen. The active species of oxygen react with a molecule layer of aminosilane adsorbed to the surface of the wafer W, thereby oxidizing aminosilane. Thus, a molecule layer formed of silicon oxide is formed. Since the forced chain decomposition of ozone proceeds instantaneously, the amount of the active species is suddenly increased within the processing space 54. In other words, the gas is suddenly expanded within the processing space 54. However, since the processing space 54 and the buffer region 62 communicate with each other as described above, the expanded gas flows into the buffer region 62, thereby preventing the pressure in the processing space 54 from becoming excessive (Step S4 of
Since the active species are unstable, the active species are changed into oxygen in, for example, several milliseconds after the active species are generated. Thus, the oxidation of aminosilane is terminated. The valves V2 and V3 are closed, and the buffer region 62, the processing space 54, and the gas supply path 55 are exhausted, thereby removing remaining oxygen (Step S5 of
Assuming that one cycle includes the adsorption of aminosilane to the wafer W, the purging of aminosilane, and the oxidation of aminosilane as described above, a change in the state of the surface of the wafer W in a cycle after a second cycle is described with reference to diagrams of
Further, heat and light energy emitted due to the chain decomposition reaction are applied to the molecules 72 of aminosilane exposed to the processing space 54 in which the chain decomposition reaction of ozone is generated. Thus, the energy of the molecules 72 momentarily rises, so a temperature of the molecules 72 rises. Further, since the active species 74 capable of reacting with the molecules 72 are present around the molecules 72 of aminosilane activated as the temperature rises as described above, the molecules 72 react with the active species 74 of oxygen. In other words, the molecules 72 of aminosilane are oxidized, thereby generating molecules 71 of silicon oxide (
Since the energy generated by the chain decomposition reaction of ozone is applied to the molecules 72 of aminosilane, the oxidation of aminosilane can be performed while the wafer W is not heated using a heater.
An overall operation of the film formation apparatus 1 is described below with reference to
Further, aminosilane gases are supplied from the gas shower heads 3A and 3B to the aminosilane adsorption regions 30A and 30B, respectively, and aminosilane is adsorbed to the surfaces of the wafers W1 and W4 (Step S11 of
The supply of the aminosilane gas to the aminosilane adsorption regions 30A and 30B is stopped, and the rotary table 12 is rotated. The wafers W1 and W4 move to the purge regions 40A and 40B respectively, and excessive aminosilane on the surfaces thereof are purged (Step S12 of
The aminosilane gas is supplied to the aminosilane adsorption regions 30A and 30B, and aminosilane is adsorbed to the wafers W5 and W2. While the aminosilane gas is being supplied, lowering of the hoods 5A and 5B, supply of the O3 gas to the processing space 54 of each of the hoods 5A and 5B, supply of the Ar gas to the buffer region 62, communication between the processing space 54 and the buffer region 62, and supply of the NO gas to the processing space 54 are sequentially performed (Step S13 of
Thereafter, the processing space 54 and the buffer region 62 are exhausted, and the hoods 5A and 5B rise. In other words, Step S5 illustrated in
Thereafter, the wafers W5 and W2 respectively move to the purge regions 40A and 40B, and excessive aminosilane on the wafers W5, W2 is purged. Further, when the wafers W4 and W1 are respectively placed under the aminosilane adsorption regions 30A and 30B while the wafers W6 and W3 are respectively placed under the hoods 5A, 5B, the rotation of the rotary table 12 is stopped. Thereafter, Step S1 to Step S6 described above are performed, so aminosilane adsorbed to the wafers W3 and W6 is oxidized. Simultaneously with the oxidation, the supply of the aminosilane gas and stop of the supply of the aminosilane gas are sequentially performed in the aminosilane adsorption regions 30A and 30B. Thus, aminosilane is adsorbed on the already formed silicon oxide layer with respect to the wafers W1 and W4 (Step S15 of
Thereafter, the rotary table 12 is rotated, and the wafers W4 and W1 respectively move to the purge regions 40A and 40B, so excessive aminosilane is purged (Step S16 of
Thereafter, the rotary table 12 is rotated, and the wafers W3 and W6 respectively move to the purge regions 40A and 40B, so excessive aminosilane is purged. Further, when the wafers W2 and W5 are respectively placed in the aminosilane adsorption regions 30A and 30B while the wafers W4, W1 being respectively placed under the hoods 5A and 5B, the rotation of the rotary table 12 is stopped. Further, as described above, the supply of the O3 gas to the processing space 54 of each of the hoods 5A and 5B, the supply of the Ar gas to the buffer region 62, communication between the processing space 54 and the buffer region 62, and the supply of the NO gas are sequentially performed (Step S17 of
Thereafter, the rotary table 12 is rotated, and the wafers W2 and W5 respectively move to the purge regions 40B and 40A, so excessive aminosilane on the wafers W2, W5 is purged. Further, when the wafers W1 and W4 are respectively placed in the aminosilane adsorption regions 30A and 30B while the wafers W3 and W6 are respectively placed under the hoods 5A and 5B, the rotation of the rotary table 12 is stopped. Further, oxidation in Step S1 to Step S6 is performed on the wafers W3 and W6. Further, aminosilane is adsorbed to the wafers W1 and W4 (
The details of subsequent processes of the wafer W are omitted, but the wafers W1 to W6 sequentially continue to move through the aminosilane adsorption region 30A or 30B, the purge region 40A or 40B, and the region under the hood 5A or 5B by the rotation of the rotary table 12, and are subject to processes. In this case, while aminosilane is being adsorbed to two of the wafers W1 to W6, oxidation is performed on other two of the wafers W1 to W6. Further, if a silicon oxide film of a predetermined film thickness is formed after a specific number of cycles are performed with respect to each of the wafers W, the wafers W1 to W6 are carried out from the film formation apparatus 1.
In accordance with the film formation apparatus 1 described above, an ozone atmosphere of a relatively high concentration is formed in the processing space 54 formed with the hoods 5A and 5B and the rotary table 12, ozone is subject to chain decomposition by the NO gas at room temperature, and aminosilane on a surface of the wafer W is oxidized by active species generated by the chain decomposition, thereby forming an oxide film. As illustrated in evaluation tests to be described later, the oxide film formed as described above has the same film quality as an oxide film formed by heating the wafer W. Accordingly, a manufacture cost and operation cost for the film formation apparatus 1 can be reduced, because a heater for heating the wafer W in order to perform oxidation does not need to be installed in the film formation apparatus 1. Further, aminosilane can be oxidized without heating the wafer W to a predetermined temperature using the heater. Accordingly, the time required for film formation can be reduced, and throughput can be improved. Further, when the O3 gas is sealed in the processing space 54 having a relatively small volume and the chain decomposition reaction is performed, the processing space 54 is communicated with the buffer region 62 to which an inert gas is supplied. Therefore, a region in which the chain decomposition reaction is generated is limited to the processing space 54. In other words, a rise of pressure in the processing space 54 can be reduced because a gas suddenly expanded in the processing space 54 is discharged to the buffer region 62. Therefore, damage or deterioration of the wafer W attributable to such a pressure rise can be suppressed. Further, damage or deterioration of the hoods 5A and 5B that form the processing space 54 can be suppressed. In other words, configuration of the film formation apparatus can be simplified because the hoods 5A and 5B do not need to have high pressure resistance, and an increase in the manufacture cost can be suppressed. Further, in the film formation apparatus 1, while aminosilane is being adsorbed to two sheets of the wafers W, oxidation is performed on other two sheets of the wafers W. As such, different processes are simultaneously performed, thus improving productivity of the film formation apparatus.
Further, when an aminosilane gas is supplied to the wafer W, the processing space 54 is partitioned from the buffer region 62. In other words, since the volume of the processing space 54 is suppressed to a small volume, a reduction in the concentration of the aminosilane gas supplied to the processing space 54 can be suppressed. In other words, the aminosilane gas does not need to have a high concentration when aminosilane is adsorbed to the wafer W, thus suppressing an increase in the operation cost of the film formation apparatus.
In the film formation apparatus 1, the gas supply path 55 opened to the processing space 54 is provided to face the surface of the wafer W loaded onto the rotary table 12. The aforementioned decomposition reaction of ozone is instantaneously performed. Since the gas supply path 55 is opened as described above, the decomposition reaction is propagated from the top to the bottom of the processing space 54 within a short time. Since the decomposition reaction is propagated as described above, a downward force is applied to the wafer W. Thus, the wafer W is pressurized toward the rotary table 12 and fixed thereto, and the aforementioned oxidation is performed while the wafer W being fixed to the rotary table 12. In other words, the wafer W can be prevented from deviating from the concave portions 14 of the rotary table 12 due to a change of pressure in the processing space 54 attributable to the chain decomposition reaction of ozone.
Further, the gas supply path 55 is opened at the central part of the processing space 54. Therefore, in the circumferential direction of the processing space 54, a pressure rise is generated with high uniformity due to a chain decomposition reaction. In other words, the pressure is prevented from being heavily applied to a specific place, thus certainly suppressing damages to the hoods 5A and 5B. The shape of the processing space 54 is configured to prevent such a local rise of pressure, but is not limited to the aforementioned example. For example, the processing space 54 may be configured to have a shape of a convex lens protruding upward.
In the examples described above, when the hoods 5A and 5B move up in Step S3 of
In the examples described above in order to form an atmosphere in which the chain decomposition reaction is generated, the pressure in the processing space 54 and the gas supply path 55 is set to 50 Torr in Steps S2 and S3, but is not limited thereto. If the chain decomposition reaction is possible, the pressure may be set to be lower than 50 Torr, for example, 20 Torr to 30 Torr. As the pressure in the processing space 54 in Steps S2 and S3 rises, the ozone concentration in the processing space 54 and the gas supply path 55 for generating the chain decomposition reaction is lowered. However, as the pressure in the processing space 54 and the gas supply path 55 in Steps S2 and S3 increases, the pressure in the processing space 54, the gas supply path 55, and the buffer region 62 increases when the chain decomposition reaction occurs. Further, even when the chain decomposition reaction is performed, the processing space 54, the gas supply path 55, and the buffer region 62 are maintained at an atmosphere lower than atmospheric pressure, in other words, a vacuum atmosphere. Accordingly, the pressure in the processing space 54 in Steps S2 and S3 is set so that the hoods 5A and 5B and the wafer W are not damaged.
In the film formation apparatus 1, a spring may be provided between a ceiling within the vacuum chamber 11 and the top of the main body portion 51 of the hoods 5A and 5B. The main body portion 51 is biased to the rotary table 12 by the spring. The hood lifting mechanism 53 is configured to resist a biasing force of the spring and raise the hoods 5A and 5B so that the rotary table 12 may be rotated. In Step S1 to Step S3 described above, the main body portion 51 is biased to the rotary table 12 by the spring and closely attached to the rotary table 12. As a result, the processing space 54 is partitioned from the adsorption space 60. Further, in Step S4, when pressure in the processing space 54 rises due to the chain decomposition reaction, the hoods 5A and 5B resist the biasing force of the spring by such a rise in the pressure and rise to the height at which the buffer region 62 and the processing space 54 communicate with each other as illustrated in
In the film formation apparatus 1, a switching between a state where the processing space 54 is communicated with the buffer region 62 and a state where the processing space 54 is partitioned from the buffer region 62 is performed by moving up and down the hoods 5A and 5B with respect to the rotary table 12. In some embodiments, the switching may be performed by providing a lifting mechanism for moving up and down the rotary table 12 with respect to the hoods 5A and 5B. In some embodiments, a rotation mechanism for rotating the gas shower heads 3A and 3B, the purge gas nozzles 4A and 4B, and the hoods 5A and 5B with respect to the table 12 may be provided without rotating the rotary table 12. The wafer W may be moved by the rotation mechanism among the aminosilane adsorption regions 30A and 30B, the purge regions 40A and 40B, and the regions under hoods 5A and 5B such that the wafer W is subject to each of the processes described above. In some embodiments, the processing space 54 may be partitioned by forming the protrusion 68 for partitioning the processing space 54 in the rotary table 12 and forming the groove 16 in the hoods 5A and 5B.
In Steps S3 and S4, in other words, when the processing space 54 is communicated with the buffer region 62 and the chain decomposition reaction is generated, the Ar gas may be sealed in the buffer region 62 without supplying the Ar gas to the buffer region 62 and performing the exhaust from the buffer region 62. Further, the gas supplied to the buffer region 62 may be any inert gas, or may be an N2 gas etc. Further, an NO gas supply passage and an O3 gas supply passage do not need to be common as in the above example, but may be individually provided.
Subsequently, a film formation apparatus in accordance with a second embodiment of the present disclosure is described below. The film formation apparatus includes a hood 8 illustrated in
Further, one end of the exhaust path 65 provided in the hood 8 is opened to a processing space 54. The other end of the exhaust path 65 is extended upward along a passage formation portion 52 and connected to one end of an exhaust pipe 81 provided outside the vacuum chamber 11. The other end of the exhaust pipe 81 is opened to a buffer region 83 within a buffer tank 82. In other words, the processing space 54 and the buffer region 83 are connected through the exhaust pipe 81. A valve V4 that forms a partition mechanism is provided in the exhaust pipe 81. Further, a downstream end of a gas supply pipe 56 connected to an Ar gas supply source 59 is opened in the buffer region 83. Further, an upstream end of the exhaust pipe 66 is opened to the buffer region 83. Although not illustrated, like the hoods 5A and 5B, the hood 8 may be connected to the hood lifting mechanism 53 and move up and down.
Based on differences between an operation of the hood 8 and the operation of the hood 5A, the operation of the hood 8 is described below. While the main body portion 51 is moved down such that a bottom surface 69 of the main body portion 51 is closely attached to the rotary table 12 and the processing space 54 is airtightly partitioned from an adsorption space 60, an O3 gas is supplied to the processing space 54, as with the hood 5A. Further, while an Ar gas is being supplied from an Ar gas supply source 59 to the buffer region 83, the buffer region 83 is exhausted by an exhaust amount adjustment unit 67. At this time, the valve V4 is closed, and the processing space 54 and the buffer region 83 are partitioned from each other.
When both of a pressure in the buffer region 83 and a pressure of the processing space 54 become, for example, 50 Torr, the supply of the O3 gas to the processing space 54 is stopped, and the valve V4 is opened. Thus, the processing space 54 communicates with the buffer region 83. Since the pressure of the processing space 54 is the same as that of the buffer region 83, a gas flow is prevented from being formed between the buffer region 83 and the processing space 54 as in the first embodiment. Thus, an O3 concentration in the processing space 54 is maintained at a concentration where a chain decomposition reaction can be generated (
Thereafter, the valve V3 is closed, the supply of the Ar gas to the buffer region 83 is stopped, and the processing space 54, the gas supply path 55, the exhaust path 65, the exhaust pipe 81, and the buffer region 83 are exhausted, thereby removing reaction products (oxygen) remaining on each of the elements. Thereafter, the exhaust of each of the elements is stopped by the exhaust amount adjustment unit 67, and the hood 8 moves up so that the rotary table 12 may be rotated. Accordingly, since each reaction is performed at room temperature on the film formation apparatus of the second embodiment where the hood 8 is provided, and the rise of pressure in the processing space 54 can be reduced as described above, the same advantages as those of the film formation apparatus 1 of the first embodiment are obtained.
Subsequently, a film formation apparatus of a third embodiment is described below. The film formation apparatus is configured in the same manner as the film formation apparatus described above, except that it includes a hood 9 configured approximately in the same manner as the hood 8. Based on differences between the hood 9 and the hood 8, the hood 9 is described with reference to
Based on differences between an operation of the hood 9 and the operation of the hood 8, the operation of the hood 9 is described below. While a main body portion 51 is moved down such that a bottom surface 69 of the main body portion 51 is closely attached to a rotary table 12 and the processing space 54 is airtightly partitioned from an adsorption space 60, an O3 gas is supplied to the processing space 54 as with the hood 8. Further, while an Ar gas is being supplied from the Ar gas supply source 59 to the exhaust pipe 81, an exhaust by the exhaust amount adjustment unit 67 is performed (
When a pressure in the processing space 54 becomes, for example, 50 Torr, a pressure on the downstream side of the valve V4 of the exhaust pipe 81 also becomes, for example, 50 Torr, the supply of an O3 gas to the processing space 54 is stopped, and the valve V4 is opened. Thus, the processing space 54 communicates with the downstream side of the valve V4 of the exhaust pipe 81. Since the pressure in the processing space 54 is the same as that on the downstream side of the valve V4 of the exhaust pipe 81, O3 is sealed in the processing space 54 and an O3 concentration is maintained at a concentration where a chain decomposition reaction can be generated as in other embodiments (
Thereafter, the valve V3 is closed, the supply of the Ar gas to the exhaust pipe 81 is stopped, and the processing space 54, the gas supply path 55, an exhaust path 65, and the exhaust pipe 81 are exhausted, thereby removing reaction products (oxygen) remaining on each of the elements. Thereafter, the exhaust of each of the elements is stopped by the exhaust amount adjustment unit 67, and the hood 9 moves up so that the rotary table 12 may be rotated. The film formation apparatus of the third embodiment where the hood 9 is installed has the same advantages as the first and the second formation apparatuses.
In each of the aforementioned embodiments, the aforementioned chain decomposition reaction is illustrated as being started by supplying energy to ozone through a chemical reaction between NO and ozone. If energy can be supplied so that the chain decomposition reaction is started, the present disclosure is not limited to the chemical reaction described above. For example, a laser beam radiation unit for radiating a laser beam to the processing space 54 may be provided in each of the hoods or the rotary table 12. Further, the chain decomposition reaction may be started by applying energy to ozone through the radiation of the laser beam. Further, an electrode may be provided in each of the hoods or the rotary table 12, and a discharge may be generated by applying a voltage to the electrode. The chain decomposition reaction may be started by applying energy generated from the discharge. However, from a viewpoint of simplifying the configuration of the film formation apparatus and of preventing a metal forming a discharge electrode from being scattered to the wafer W, the chain decomposition reaction may be generated by the generation of the aforementioned chemical reaction. A gas for applying energy is not limited to the NO gas, but may be any gas capable of generating the aforementioned chain decomposition reaction.
However, for example, in the film formation apparatus 1, the NO gas may be supplied to the processing space 54, while an ammonia gas, a methane gas, or a diborane gas, together with the ozone gas, being supplied to the processing space 54. When O3 is decomposed, the gases may be also decomposed to chemically react with aminosilane, thereby forming a silicon oxide film doped with elements that form the gases. Specifically, a silicon oxide film doped with nitrogen (N), carbon (C), or boron (B) can be formed by supplying ammonia, a methane gas, or a diborane gas to the processing space 54. If such doping is performed in each of the embodiments, each the gases for the doping is supplied to the processing space 54 until the NO gas is supplied to the processing space 54 after the processing space 54 is airtightly configured. When each of the gases for the doping is supplied, the gas supply pipe 55 provided in each of the hoods may be used.
The raw material gas applied to the embodiments is not limited to the formation of the silicon oxide film as described above. For example, an aluminum oxide, hafnium oxide, strontium oxide, or titanium oxide film may be formed using trimethylaluminum [TMA], tetrakis(ethylmethyl)aminohafnium [TEMHF], strontium bis(tetramethylheptanedionate) [Sr(THD)2], or titanium methylpentanedionato bis(tetramethylheptanedionate) [Ti(MPD)(THD)].
Evaluation tests performed in relation to the present disclosure are described below. For an evaluation test 1, as described in each embodiment, a silicon oxide film was formed on the wafer W by supplying various gases to the processing space within the vacuum chamber at room temperature and repeatedly performing the aforementioned cycle including the adsorption of aminosilane, the purge of the surface of the wafer W, and the oxidation of aminosilane by the chain decomposition reaction of ozone. Further, the silicon oxide film formed using the film formation apparatus was subjected to wet etching, and an etching rate was measured. In the evaluation test 1, an etching rate on one side of the wafer W was measured, and an etching rate on the other side thereof was measured. Further, unlike the film formation apparatus described in each of the embodiments, the film formation apparatus used in the evaluation test 1 is a sheet-type processing apparatus for carrying a sheet of the wafer W in the vacuum chamber and performing processing on the wafer W, and the region partitioned by the lifting of the hood within the vacuum chamber is not formed
For a comparison test 1-1, a silicon oxide film was formed on the wafer W using a film formation apparatus capable of generating plasma from an oxygen gas in a vacuum chamber. More specifically, like the film formation apparatus used in the evaluation test 1, the film formation apparatus used in the comparison test 1-1 may supply a raw material gas to the vacuum chamber and also generate plasma from the oxygen supplied to the vacuum chamber. Further, the film formation may be conducted by alternately performing the supply of the raw material gas and the oxidization of the raw material gas using the plasma. As in the evaluation test 1, the oxidation was performed at room temperature in the comparison test 1-1. After the film was formed, the silicon oxide film was subjected to wet etching and etching rates were measured as in the evaluation test 1.
For a comparison test 1-2, while the wafer W within the vacuum chamber was being heated to a predetermined temperature using a heater, a silicon oxide film was formed on the wafer W by repeatedly performing alternately supplying the raw material gas for forming a film and supplying an ozone gas to the wafer W. In other words, in the comparison test 1-2, a chain decomposition reaction of ozone was not performed, and thermal energy was applied to the wafer W by heating the wafer W such that aminosilane adsorbed to the wafer W was oxidized by ozone. After the film was formed, etching rates were measured as in other tests.
Subsequently, an evaluation test 2 performed to examine a heat history of the silicon oxide film formed by performing the processes according to the embodiments is described below. In the evaluation test 2, phosphorus (P) was injected into a plurality of substrates made of silicon through ion implantation. The ion implantation was performed at 2 keV and 1E15 ions/cm2. Further, using the film formation apparatus used in the evaluation test 1, a silicon oxide film was formed on the substrates into which phosphorous (P) was injected. In forming the silicon oxide film, the cycle was performed 100 times. Further, in Step S3 of each cycle, an ozone gas was supplied so that an ozone concentration within the processing space in the vacuum chamber became 77.7 Vol. %. Further, after the silicon oxide film was formed, the resistance value of the silicon oxide film was measured. Further, heating processing was performed on substrates that belong to the substrates into which phosphorous (P) was injected and on which the silicon oxide film was not formed at different temperatures for 5 minutes as references. After the heating process, the resistance values of the references were measured.
In accordance with the embodiments of the present disclosure, an ozone atmosphere capable of generating a forced decomposition reaction (chain decomposition reaction) within the processing space is formed, and the raw material adsorbed to the substrate is oxidized using the active species of oxygen generated by the decomposition reaction. Relatively great energy is applied to a surface of the substrate for a very short time through the decomposition reaction, whereby active species react with the raw material. Therefore, although the substrate is not heated using a heating mechanism, such as a heater, the oxidation may be sufficiently performed, thereby obtaining an oxide film having good properties. Further, when the decomposition reaction is generated, the processing space communicates with the buffer region to which an inert gas is supplied, thus suppressing an excessive rise of pressure within the processing space. As a result, the damage or deterioration of the substrate and the processing space formation member can be suppressed.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosures. Indeed, the embodiments described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosures. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-123514 | Jun 2014 | JP | national |
