WO2006098565A1

WO2006098565A1 - Method of depositing thin film using ald process

Info

Publication number: WO2006098565A1
Application number: PCT/KR2006/000829
Authority: WO
Inventors: Hong-Joo Lim; Sang-Kwon Park; Sahng-Kyu Lee; Tae-Wook Seo; Ho-Seung Chang
Original assignee: Ips Ltd.
Priority date: 2005-03-16
Filing date: 2006-03-09
Publication date: 2006-09-21
Also published as: TW200634175A; TWI312013B

Abstract

Provided is a method of depositing a thin film on a substrate using an ALD process. The method is performed using a thin film deposition device including a chamber for depositing the thin film on the substrate, a gas box for supplying a reaction gas and/or a purge gas to the chamber, and an exhaust pump for exhausting the reaction gas and/or the purge gas from the chamber and/or the gas box to the outside. In the method, a process cycle is preformed several times to deposit the thin film on the substrate. The process cycle includes a first feeding process of feeding a first reaction gas into the chamber, a first purge process of purging the first reaction gas from the chamber, a second feeding process of feeding a second reaction gas into the chamber, and a second purge process of purging the second reaction gas not reacting with the first reaction gas. Without supply of the first reaction gas and the second reaction gas, a pre-pressure change process is further performed between the repeated process cycles to decrease or increase the internal pressure of the chamber.

Description

METHOD OF DEPOSITING THIN FILM USING ALD PROCESS

Technical Field

[1] The present invention relates to a method of depositing a thin film using an atomic layer deposition (ALD) process, and more particularly, to a method of depositing a thin film using an ALD process, which can achieve good or bad step coverage on a substrate and also enhance a purge efficiency.

Background Art

[2] FIG. 1 is a graph illustrating a process sequence of a conventional ALD thin film deposition method.

[3] Referring to FIG. 1, in the conventional ALD thin film deposition method, a process cycle is performed several times to deposit a thin film on a substrate. The process cycle includes: a first feeding process Sl of feeding a first reaction gas into a chamber in which the substrate is installed; a first purge process S2 of purging the first reaction gas from the chamber; a second feeding process S3 of feeding a second reaction gas into the chamber; and a second purge process S4 of purging the second reaction gas not reacting with the first reaction gas. When the process cycle is performed once, a first atomic layer or a first molecular layer is deposited on the substrate.

[4] Meanwhile, the increasing integration degree of semiconductor devices necessitates good step coverage in a contact. In order to achieve this good step coverage, the supply time and flow rate of the first or second reaction gas, and the purge time and flow rate of a purge gas are sufficiently increased to induce a sufficient surface reaction.

Disclosure of Invention

Technical Problem

[5] However, when the feeding and purging processes are performed for a long time, the corresponding productivity decreases.

[6] On the other hand, in performing ALD thin film deposition, bad step coverage is required in order to form a barrier in a contact hole, for example. To this end, the flow rate of the first or second reaction gas is decreased to cause the reaction to occur only at the entrance of the contact hole, or the purge time or the flow rate of the purge gas is reduced to cause the purge operation to be insufficiently performed. However, this method is problematic in that process reproducibility and control of thickness uniformity or particle generation are difficult to achieve. The method is also problematic in that its performance greatly depends on hardware characteristics, particularly because the gas flow of a shower head must be controlled to be very uniform. These problems lead to a decrease in productivity.

[7] Meanwhile, in the fabrication of a semiconductor device, the surface area of a substrate on which a pattern has been formed is several hundred % larger than that of a substrate on which no pattern has been formed. Moreover, with the progress of high integration, the surface area of the substrate is further increased due to an increase in the aspect ratio of a contact. However, when the surface area of the substrate increases, the purge time must be increased in order to enhance the purge efficiency of the reaction gas. This increase in the purge time leads to a decrease in productivity.

Technical Solution

[8] The present invention provides an ALD thin film deposition method that can easily achieve good or bad step coverage on a substrate.

[9] The present invention also provides an ALD thin film deposition method that can efficiently purge a reaction gas from a chamber and a gas line within a short time and can enhance the uniformity of the resulting thin film.

[10] According to an aspect of the present invention, there is provided a method of depositing a thin film on a substrate using an ALD process and a thin film deposition device including a chamber for depositing the thin film on the substrate, a gas box for supplying a reaction gas and/or a purge gas to the chamber, and an exhaust pump for exhausting the reaction gas and/or the purge gas from the chamber and/or the gas box to the outside, the method including: performing cycle a process a number of times to deposit the thin film on the substrate, the repeated process cycle including: a first feeding process of feeding a first reaction gas into the chamber; a first purge process of purging the first reaction gas from the chamber; a second feeding process of feeding a second reaction gas into the chamber; and a second purge process of purging the second reaction gas not reacting with the first reaction gas; and performing, between the repeated process cycles, a pre-pressure change process of decreasing or increasing an internal pressure of the chamber without supplying the first reaction gas and the second reaction gas.

[11] When the thin film deposited on the substrate needs to have good step coverage, the pre-pressure change process may be performed to decrease an internal pressure of the chamber below a process pressure at which the first and second feeding and purging processes are performed. The pre-pressure change process may be performed via a pumping operation of the exhaust pump after closing valves connected between the chamber and the gas box. The pre-pressure change process may be performed to decrease the internal pressure of the chamber by greater than 20% of a process pressure of the first feeding process.

[12] When the thin film deposited on the substrate needs to have bad step coverage, the pre-pressure change process may be performed to increase an internal pressure of the chamber above a process pressure at which the first and second feeding and purging processes are performed. The pre-pressure change process may be performed by supplying a separate inert gas to the chamber. The separate inert gas may be supplied through a separate gas line additionally connected between the chamber and the gas box, or through first and second gas lines connected between the chamber and the gas box. The pre-pressure change process may be performed to increase the internal pressure of the chamber by greater than 20% of a process pressure of the first feeding process.

[13] The gas box may include two or more reaction gas supply units respectively supplying two or more kinds of reaction gas to the chamber; a main purge gas supply unit supplying a main purge gas for purging the chamber; a connection line connecting the reaction gas supply unit to the chamber; a bypass line connecting the exhaust pump to the reaction gas supply units and/or the main purge gas supply unit; and a plurality of valves installed in the reaction gas supply units, the main purge gas supply unit, the connection line and the bypass line. The reaction gas supply unit may include: a source container filled with a predetermined amount of liquid reactant to be gasified by a supplied carrier gas; and a plurality of valves selectively allowing the carrier gas to flow to the source container, the connection line or the bypass line. The first purge process and/or the second purge process may include at least two processes of a first sub-purge process performed using the carrier gas, a second sub-purge process performed using the main purge gas, and a third sub-purge process performed via a pumping operation of the exhaust pump after closing all of the valves installed in the connection lines connected to the chamber.

[14] The first purge process and/or the second purge process may include the first sub- purge process and the second sub-purge process.

[15] The first purge process and/or the second purge process may include the second sub-purge process and the third sub-purge process.

[16] The first purge process and/or the second purge process may include the first sub- purge process, the second sub-purge process, and the third sub-purge process.

Description of Drawings

[17] FIG. 1 is a graph illustrating a process sequence of a conventional ALD thin film deposition method;

[18] FIG. 2 is a schematic diagram illustrating a structure of a thin film deposition device used for performing an ALD thin film deposition method according to an embodiment of the present invention;

[19] FIG. 3 is a graph illustrating a process sequence of an ALD thin film deposition method for achieving good step coverage according to an embodiment of the present invention; [20] FIG. 4 is a graph illustrating a process sequence of an ALD thin film deposition method for achieving bad step coverage according to an embodiment of the present invention;

[21] FIG. 5 is a schematic diagram illustrating a structure of a thin film deposition device performing the process sequence of the ALD thin film deposition method illustrated in FIG. 4;

[22] FIG. 6 is a schematic diagram illustrating a structure of a thin film deposition device used for performing an ALD thin film deposition method according to another embodiment of the present invention;

[23] FIG. 7 is a graph illustrating a process sequence of an ALD thin film deposition method using the thin film deposition device of FIG. 6, wherein a second purge process includes first and second sub-purge processes; and

[24] FIG. 8 is a graph illustrating a process sequence of an ALD thin film deposition method using the thin film deposition device of FIG. 6, wherein a second purge process includes first, second and third sub-purge processes.

Best Mode

[25] The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.

[26] An ALD thin film deposition method according to an embodiment of the present invention will now be described in detail.

[27] FIG. 2 is a schematic diagram illustrating a structure of a thin film deposition device used for performing an ALD thin film deposition method according to an embodiment of the present invention. FIG. 3 is a graph illustrating a process sequence of an ALD thin film deposition method for achieving good step coverage according to an embodiment of the present invention. FIG. 4 is a graph illustrating a process sequence of an ALD thin film deposition method for achieving bad step coverage according to an embodiment of the present invention. FIG. 5 is a schematic diagram illustrating a structure of a thin film deposition device performing the process sequence of the ALD thin film deposition method illustrated in FIG. 4.

[28] Referring to FIG. 2, the thin film deposition device used for performing the ALD thin film deposition method includes: a chamber 100 for depositing a thin film on a substrate W; a gas box 200 for supplying a reaction gas and/or a purge gas to the chamber 100; and an exhaust pump 300 for exhausting the chamber 100 and/or the gas box 200 of the reaction gas and/or the purge gas.

[29] The gasbox 200 and the chamber 100 are connected to each other by a first gas line in which a first valve Vl is installed and a second gas line in which a second valve V2 is installed. The first gas line is connected to a first bypass line in which a third valve V3 is installed, and the second gas line is connected to a second bypass line in which a fourth valve V4 is installed. A fifth valve V5 is installed in a gas line connected between the chamber 100 and the exhaust pump 300. Although not illustrated in FIG. 2, a purge valve may be further installed.

[30] The ALD thin film deposition method includes: performing a process cycle a number of times, the process cycle including a first feeding process SlO of feeding a first reaction gas into the chamber 100, a first purge process S20 of purging the first reaction gas from the chamber 100, a second feeding process S30 of feeding a second reaction gas into the chamber 100, and a second purge process S40 of purging the second reaction gas not reacting with the first reaction gas; and performing, between the repeated process cycles, a pre-pressure change process S50 or S50' (see FIGS. 3 and 4) of decreasing or increasing the internal pressure of the chamber 100 without supply of the first and second reaction gas.

[31] The pre-pressure change process S50 or S50' is used to decrease or increase the internal pressure of the chamber 100, to achieve good or bad step coverage on the substrate W. These two cases will now be described separately.

[32] ( 1 ) For Good Step Coverage

[33] Referring to FIG. 3, a process cycle of the pre-pressure change process S50 a the first feeding process SlO a the first purge process S20 a the second feeding process S30 a the second purge process S40 is repeated several times. When a first process cycle 1 is performed, a first atomic layer or a first molecular layer is deposited on the substrate W. At this point, the chamber 100 may be purged using an inert gas such as Ar or N 2.

[34] When a thin film to be deposited on the substrate W needs to have good step coverage, the pre-pressure change process S50 is performed to decrease the internal pressure of the chamber 100 below a process pressure at which the feeding and purging processes are performed. The pre-pressure change process S50 is performed by closing the first and second valves Vl and V2 installed respectively in the first gas line and the second gas line and then performing a pumping operation of the exhaust pump 300. At this point, the pre-pressure change process S50 may be performed to decrease the internal pressure of the chamber 100 by more than 20% of a predetermined process pressure of the first feeding process SlO. The reason for this is that the internal pressure of a contact hole is insufficiently decreased when the pre-pressure change process S50 is performed to decrease the internal pressure of the chamber 100 by less than 20% of the predetermined process pressure.

[35] As described above, unlike the conventional ALD thin film deposition method, the pre-pressure change process S50 is further performed to decrease the internal pressure of the chamber 100, thereby decreasing the pressure at the surface of the substrate W (specifically, the internal pressure of the contact hole). Due to this pressure decrease, the reaction gas is sufficiently supplied to the inside of the contact hole during the next process cycle, thereby achieving good step coverage. That is, the decreased pressure at the surface of the substrate W increases the diffusion distance and speed of the reaction gas, and thus the reaction gas can be supplied to the deep inside of the contact hole, thereby achieving good step coverage.

[36] (2) For Bad Step Coverage

[37] Referring to FIG. 4, a process cycle of the pre-pressure change process S50' a the first feeding process SlO a the first purge process S20 a the second feeding process S30 a the second purge process S40 is performed several times. When a first process cycle 1 is performed, a first atomic layer or a first molecular layer is deposited on the substrate W. At this point, the chamber 100 may be purged using an inert gas such as Ar or N 2.

[38] When a thin film to be deposited on the substrate W needs to have bad step coverage, the pre-pressure change process S50' is performed to increase the internal pressure of the chamber 100 above a process pressure at which the feeding and purging processes are performed.

[39] Referring to FIG. 5, an inert gas for the pre-pressure change process S50' may be supplied through the first and second gas lines, or through a separate gas line 400 that is additionally connected between the gasbox 200 and the chamber 100. When the inert gas is supplied through the separate gas line 400, the pre-pressure change process S50' can be performed more precisely.

[40] The pre-pressure change process S50' may be performed to increase the internal pressure of the chamber 100 by more than 20% of a predetermined process pressure of the first feeding process SlO. The reason for this is that the internal pressure of a contact hole is insufficiently increased when the pre-pressure change process S50' is performed to increase the internal pressure of the chamber 100 by less than 20% of the predetermined process pressure.

[41] As described above, unlike the conventional ALD thin film deposition method, the pre-pressure change process S50' is further performed to increase the internal pressure of the chamber 100, thereby increasing the pressure at the surface of the substrate W (specifically, the internal pressure of the contact hole). Due to this pressure increase, the reaction gas fed is not supplied to the inside of the contact hole during the next process cycle, thereby achieving bad step coverage. That is, the increased pressure at the surface of the substrate W decreases the diffusion distance and speed of the reaction gas, and thus the reaction gas reacts mainly at the entrance region of the contact hole, thereby achieving bad step coverage.

[42] An ALD thin film deposition method according to another embodiment of the present invention will now be described in detail. [43] FIG. 6 is a schematic block diagram of a thin film deposition device used for performing an ALD thin film deposition method according to another embodiment of the present invention. FIG. 7 is a graph illustrating a process sequence of an ALD thin film deposition method using the thin film deposition device of FIG. 6, wherein a second purge process includes first and second sub-purge processes unlike the embodiment of FIG. 2. FIG. 8 is a graph illustrating a process sequence of an ALD thin film deposition method using the thin film deposition device of FIG. 6, wherein a second purge process includes first, second and third sub-purge processes unlike the embodiment of FIG. 2.

[44] Referring to FIG. 6, the thin film deposition device used for performing the ALD thin film deposition method includes: a chamber 100 for depositing a thin film on a substrate W; a gas box 200 for supplying a reaction gas and/or a purge gas to the chamber 100; and an exhaust pump 300 for exhausting the chamber 100 and/or the gas box 200 of the reaction gas and/or the purge gas. At this point, the exhaust pump 300 operates continuously during the ALD thin film deposition process.

[45] The gas box 200 includes: two or more reaction gas supply units respectively supplying two or more kinds of reaction gases to the chamber 100; a main purge gas supply unit supplying a main purge gas for purging the chamber 100; connection lines connecting the reaction gas supply units to the chamber 100; a bypass line connecting the exhaust pump 300 to the reaction gas supply units and/or the main purge gas supply unit; and a plurality of valves installed in the reaction gas supply units, the main purge gas supply unit, the connection line and the bypass line.

[46] Each of the reaction gas supply units includes: a source container filled with a predetermined amount of liquid reactant to be gasified by a supplied carrier gas; and a plurality of valves selectively allowing the carrier gas to flow to the source container, the connection line or the bypass line.

[47] As a simple descriptive example, the gas box 200 includes: first and second reaction gas supply units 210 and 230 respectively supplying first and second kinds of reaction gases (i.e., first and second reaction gases) to the chamber 100; first and second main purge gas supply units 250 and 260 supplying a main purge gas for purging the chamber 100; first and second connection lines 220 and 240 connecting the chamber 100 to the first reaction gas supply unit 210 and the second reaction gas supply unit 230, respectively; first and second bypass lines 225 and 245 connecting the exhaust pump 300 to the first and second reaction gas supply units 210 and 230 and the first and second main purge gas supply units 250 and 260, respectively. It will be apparent that first, second and third reaction gas supply units, first, second and third main purge gas supply units, first, second and third connection lines, and first, second and third bypass lines are used when the gas box 200 is configured to supply three kinds of gases.

[48] As a simple descriptive example, only the second reaction gas supply unit 230 includes a source container 231 filled with liquid reactant, while the first reaction gas supply unit 210 uses gaseous ozone.

[49] The first reaction gas supply unit 210 includes on/off valves 212a and 212b that allow the first reaction gas (e.g., ozone) to flow to the first connection line 220 or the first bypass line 225.

[50] The first main purge gas supply unit 250 includes on/off valves 252a and 252b that allow the main purge gas to flow to the first connection line 220 or the first bypass line 225. The main purge gas may be non-reactant gas (e.g., Ar, N , and He), and its flow may be controlled by a mass flow controller (MFC).

[51] The second reaction gas supply unit 230 includes the source container 231 and on/ off valves 232a, 232b, 232c, 232d and 232e. The liquid reactant filling the source container 231 is gasified into the second reaction gas by an inert gas flowing in through the on/off valve 232a. This inert gas may be Ar and is hereinafter referred to as carrier gas. The valves 232a, 232b, 232c, 232d and 232e are controlled to allow the second reaction gas to flow through the second connection line 240 or the second bypass line 245.

[52] The second main purge gas supply unit 260 includes on/off valves 262a and 262b that allow the main purge gas to flow to the second connection line 240 or the second bypass line 245. The main purge gas may be a non-reactant gas such as Ar, N , and He, and its flow may be controlled by an MFC.

[53] The valves 232a, 232b, 232c, 232d and 232e are controlled by a controller (not illustrated).

[54] The ALD thin film deposition method using the thin film deposition device of FIG.

6 will now be described in detail with reference to FIGS. 7 and 8.

[55] The ALD thin film deposition method includes: performing a process cycle a number of times, the process cycle including a first feeding process SlO of feeding the first reaction gas into the chamber 100, a first purge process S20 of purging the first reaction gas from the chamber 100, a second feeding process S30 of feeding the second reaction gas into the chamber 100, and a second purge process S40 of purging the second reaction gas not reacting with the first reaction gas; and performing, between the repeated process cycles, a pre -pressure change process S50 or S50' (see FIGS. 3 and 4) of decreasing or increasing the internal pressure of the chamber 100 without supply of the first and second reaction gas. The pre-pressure change processes S50 and S50' are identical to those of the embodiment of FIGS. 2 through 5, and descriptions thereof will be omitted for conciseness. When a first process cycle 1 is performed, a first atomic layer or a first molecular layer is deposited on the substrate W.

[56] In the first feeding process SlO, the valve 212a of the first reaction gas supply unit

210 is opened to feed the first reaction gas (e.g., ozone) through the first connection line 220 to the chamber 100. In the chamber 100, the first reaction gas is adhered onto the substrate W.

[57] In the first purge process S20, the valve 252a of the first main purge gas supply unit 250 is opened to supply the main purge gas through the first connection line 220 into the chamber 100, thereby purging the first reaction gas in the chamber 100 not adhered onto the substrate W. The first reaction gas purged is exhausted outside through the exhaust pump 300.

[58] In the second feeding process S30, the valves 232a, 232b and 232e of the second reaction gas supply unit 230 are opened. Then, a carrier gas, e.g., Bubble Ar, flows in and bubbles the reaction gas of the source container 231 to generate the second reaction gas. This second reaction gas is fed to the chamber 100 through the valves 232b, 232e and the second connection line 240. In the chamber 100, the second reaction gas reacts with the first reaction gas adhered onto the substrate W, thereby depositing the first atomic layer or the first molecular layer on the substrate W.

[59] The second purge process S40 includes at least two processes of a first sub-purge process S40a, a second sub-purge process S40b, and a third sub-purge process S40c. The first sub-purge process S40a is performed using the carrier gas, Bubble Ar. The second sub-purge process S40b is performed using the main purge gas. The third sub- purge process S40c is performed via a pumping operation of the exhaust pump 300 after closing all of the valves installed in the connection lines connected to the chamber 100.

[60] For example, as illustrated in FIG. 7, the second purge process S40 may include the first sub-purge operation S40a and the second sub-purge operation S40b.

[61] Alternatively, the second purge process S40 may include the second sub-purge operation S40b and the third sub-purge operation S40c.

[62] For another example, as illustrated in FIG. 8, the second purge process S40 may include the first sub-purge operation S40a, the second sub-purge operation S40b, and the third sub-purge operation S40c.

[63] In the first sub-purge process S40a, the valve 232a of the second reaction gas supply unit 230 is closed and the valves 232c and 232e are opened to supply the carrier gas through the second connection line 240 to the chamber 100, thereby purging the second reaction gas remaining in the second connection line 240.

[64] In the second sub-purge process S40b, the valve 262a of the second main purge gas supply unit 260 is opened to supply the main purge gas through the second connection line 240 to the chamber 100, thereby purging the chamber 100 of reaction by-products and/or the second reaction gas not reacting with the first reaction gas.

[65] In the third sub-purge process S40c, the valves 212a, 252a, 232e and 262a installed in the connection lines 220 and 240 are all closed and then a purge operation is performed via a pumping operation of the exhaust pump 300.

[66] The second reaction gas and the reaction by-products, which have been purged during the first, second and third sub-purge processes S40a, S40b and S40c, are exhausted outside via the exhaust pump 300.

[67] It has been described that the first reaction gas supply unit 210 does not include a source container because it uses ozone. However, when the first reaction gas supply unit 210 includes a source container filled with liquid reactant like the second reaction gas supply unit 230, the first purge process S20 may include at least one of the first, second and third sub-purge processes like the second purge process S40.

[68] It has been described that the feeding and purge processes are performed using the first reaction gas and the second reaction gas. However, when the feeding and purging processes are performed using three kinds of gases (i.e., first, second and third reaction gases), the ALD thin film deposition method may include: performing a process cycle a number of times, the process cycle including a first feeding process of feeding the first reaction gas into the chamber 100, a first purge process of purging the first reaction gas from the chamber 100, a second feeding process of feeding the second reaction gas into the chamber 100, a second purge process of purging the second reaction gas from the chamber 100, a third feeding process of feeding the third reaction gas into the chamber 100, and a third purge process of purging the chamber 100 of byproducts and/or the third reaction gas not reacting with the first and second reaction gases; and performing, between the repeated process cycles, a pre-pressure change process S50 or S50' of decreasing or increasing the internal pressure of the chamber 100 without supply of the first, second and third reaction gases.

[69] In this case, as described above, the first purge process and/or the second purge process and/or the third purge process may include at least two processes of a first sub- purge process S40a performed using the carrier gas, a second sub-purge process S40b performed using the main purge gas, and a third sub-purge process S40c performed via a pumping operation of the exhaust pump 300 after closing all of the valves installed in the connection lines connected to the chamber 100.

[70] When the purge process includes the several sub-purge processes as described above, the reaction gas can be completely purged from the connection line or the chamber 100 within a short time, thereby maximizing the surface reaction on the substrate.

[71] State of the art semiconductor devices have a nano-level structure and thus their contact holes have a more minute structure. Therefore, even when an ALD deposition method is used, if a reaction gas is inefficiently purged, desired device characteristics are unable to be obtained.

[72] However, according to the present invention, the reaction gas and by-products remaining on the substrate are efficiently purged by the several sub-purge processes of the purge process, and thus good thin film characteristics can be obtained.

[73] Also, the purge process is completed within a shorter time and simultaneously the purge efficiency is enhanced, thereby increasing the productivity.

[74] As described above, the pre-pressure change process S50 or S50' of decreasing or increasing the internal pressure of the chamber 100 is additionally performed after each process cycle comprising the first feeding process a the first purge process a the second feeding process a the second purge process. Accordingly, the internal pressure of the contact hole on the substrate can be reduced or increased. When the internal pressure of the contact hole is reduced, the reaction gas supplied during the next process cycle flows into the contact hole and provides sufficient reaction, thereby achieving good step coverage. On the other hand, when the internal pressure of the contact hole is increased, the reaction gas supplied during the next process cycle cannot flow into the contact hole and reacts only at the entrance portion of the contact hole, thereby achieving bad step coverage.

[75] Also, the purge processes includes at least two processes of the first sub-purge process performed using the carrier gas, the second sub-purge process performed using the main purge gas, and the third sub-purge process performed via the pumping operation of the exhaust pump after closing all of the valves connected to the chamber. Accordingly, the reaction gas in the connection line and the chamber can be completely purged within a short time, and the remaining gas in the contact hole can be completely purged. Consequently, it is possible to achieve good thin film characteristics.

[76] While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

Claims

[1] A method of depositing a thin film on a substrate using an ALD (atomic layer deposition) process and a thin film deposition device comprising a chamber for depositing the thin film on the substrate, a gas box for supplying a reaction gas and/or a purge gas to the chamber, and an exhaust pump for exhausting the reaction gas and/or the purge gas from the chamber and/or the gas box to the outside, the method comprising: performing a process cycle a number of times to deposit the thin film on the substrate, the process cycle comprising: a first feeding process of feeding a first reaction gas into the chamber; a first purge process of purging the first reaction gas from the chamber; a second feeding process of feeding a second reaction gas into the chamber; and a second purge process of purging the second reaction gas not reacting with the first reaction gas; and performing, between the repeated process cycles, a pre-pressure change process of decreasing or increasing an internal pressure of the chamber without supplying the first reaction gas and the second reaction gas.

[2] The method of claim 1, wherein, when the thin film deposited on the substrate needs to have good step coverage, the pre-pressure change process is performed to decrease an internal pressure of the chamber below a process pressure at which the first and second feeding and purging processes are performed.

[3] The method of claim 2, wherein the pre-pressure change process is performed via a pumping operation of the exhaust pump after closing valves connected between the chamber and the gas box.

[4] The method of claim 2, wherein the pre-pressure change process is performed to decrease the internal pressure of the chamber by greater than 20% of a process pressure of the first feeding process.

[5] The method of claim 1, wherein, when the thin film deposited on the substrate needs to have bad step coverage, the pre-pressure change process is performed to increase an internal pressure of the chamber above a process pressure at which the first and second feeding and purging processes are performed.

[6] The method of claim 5, wherein the pre-pressure change process is performed by supplying a separate inert gas to the chamber.

[7] The method of claim 6, wherein the separate inert gas is supplied through a separate gas line additionally connected between the chamber and the gas box, or through first and second gas lines connected between the chamber and the gas box.

[8] The method of claim 6, wherein the pre-pressure change process is performed to increase the internal pressure of the chamber by greater than 20% of a process pressure of the first feeding process.

[9] The method of claim 1, wherein the gas box comprises two or more reaction gas supply units respectively supplying two or more kinds of reaction gas to the chamber; a main purge gas supply unit supplying a main purge gas for purging the chamber; a connection line connecting the reaction gas supply unit to the chamber; a bypass line connecting the exhaust pump to the reaction gas supply units and/or the main purge gas supply unit; and a plurality of valves installed in the reaction gas supply units, the main purge gas supply unit, the connection line and the bypass line; the reaction gas supply unit comprises: a source container filled with a predetermined amount of liquid reactant to be gasified by a supplied carrier gas; and a plurality of valves selectively allowing the carrier gas to flow to the source container, the connection line or the bypass line; and the first purge process and/or the second purge process comprise(s) at least two processes of a first sub-purge process performed using the carrier gas, a second sub-purge process performed using the main purge gas, and a third sub-purge process performed via a pumping operation of the exhaust pump after closing all of the valves installed in the connection lines connected to the chamber.

[10] The method of claim 9, wherein the first purge process and/or the second purge process comprise(s) the first sub-purge process and the second sub-purge process.

[11] The method of claim 9, wherein the first purge process and/or the second purge process comprise(s) the second sub-purge process and the third sub-purge process.

[12] The method of claim 9, wherein the first purge process and/or the second purge process comprise(s) the first sub-purge process, the second sub-purge process, and the third sub-purge process.