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Publication numberUS20040182415 A1
Publication typeApplication
Application numberUS 10/765,296
Publication dateSep 23, 2004
Filing dateJan 27, 2004
Priority dateJan 29, 2003
Also published asCN1519889A
Publication number10765296, 765296, US 2004/0182415 A1, US 2004/182415 A1, US 20040182415 A1, US 20040182415A1, US 2004182415 A1, US 2004182415A1, US-A1-20040182415, US-A1-2004182415, US2004/0182415A1, US2004/182415A1, US20040182415 A1, US20040182415A1, US2004182415 A1, US2004182415A1
InventorsSoo Yoon, Geun Yeom, Nae Lee, Ki Kim, Chang Oh, Ji Kim
Original AssigneeYoon Soo Sik, Yeom Geun Young, Lee Nae Eung, Kim Ki Joon, Oh Chang Hyun, Kim Ji Hwang
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Cleaning method of apparatus for manufacturing semiconductor device
US 20040182415 A1
Abstract
A cleaning method of an apparatus for manufacturing a semiconductor device includes providing a first cleaning gas and a second cleaning gas into a chamber, and forming a mixture of the first cleaning gas and the second cleaning gas, wherein the first cleaning gas includes a fluorocarbon gas and an oxygen gas and the second cleaning gas includes nitrogen, activating the mixture of the first cleaning gas and the second cleaning gas by a high frequency power, and exhausting residues cleaned by the activated mixture and remaining gases.
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Claims(13)
What is claimed is:
1. A cleaning method of an apparatus for manufacturing a semiconductor device, comprising:
providing a first cleaning gas and a second cleaning gas into a chamber, and forming a mixture of the first cleaning gas and the second cleaning gas, the first cleaning gas including a fluorocarbon gas and an oxygen gas, the second cleaning gas including nitrogen;
activating the mixture of the first cleaning gas and the second cleaning gas by a high frequency power; and
exhausting residues cleaned by the activated mixture and remaining gases.
2. The method according to claim 1, wherein the fluorocarbon gas is one of C3F8, C4F8 and C4F80.
3. The method according to claim 1, wherein the second cleaning gas includes one of N2, N2O and NO.
4. The method according to claim 1, wherein a flow rate of the fluorocarbon gas to the oxygen gas is within a range of 0.1 to 0.5.
5. The method according to claim 1, wherein a flow rate of the second cleaning gas to the first cleaning gas is within a range of 0.01 to 0.5.
6. The method according to claim 1, wherein the mixture of the first cleaning gas and the second cleaning gas is activated in a plasma generator outside the chamber.
7. The method according to claim 1, wherein the mixture of the first cleaning gas and the second cleaning gas cleans silicon, silicon nitride and silicon oxide in the chamber.
8. A cleaning method of an apparatus for manufacturing a semiconductor device, comprising:
activating a first cleaning gas by a high frequency power, the first cleaning gas including a fluorocarbon gas and an oxygen gas;
activating a second cleaning gas by a high frequency power, the second cleaning gas including nitrogen;
mixing the activated first cleaning gas and the activated second cleaning gas, thereby forming a mixture of the first cleaning gas and the second cleaning gas; and
exhausting residues cleaned by the mixtuer and remaining gases.
9. The method according to claim 8, wherein the fluorocarbon gas is one of C3F8, C4F8 and C4F80.
10. The method according to claim 8, wherein the second cleaning gas includes one of N2, N2O and NO.
11. The method according to claim 8, wherein a flow rate of the fluorocarbon gas to the oxygen gas is within a range of 0.1 to 0.5.
12. The method according to claim 8, wherein a flow rate of the second cleaning gas to the first cleaning gas is within a range of 0.01 to 0.5.
13. The method according to claim 8, wherein the mixture of the first cleaning gas and the second cleaning gas cleans silicon, silicon nitride and silicon oxide in the chamber.
Description
  • [0001]
    The present invention claims the benefit of Korean Patent Application No. 2003-05789, filed in Korea on Jan. 29, 2003, which is hereby incorporated by reference.
  • BACKGROUND OF THE INVENTION
  • [0002]
    1. Field of the Invention
  • [0003]
    The present invention relates to a cleaning method of an apparatus for manufacturing a semiconductor device, and more particularly, to a cleaning method of an apparatus for depositing thin films.
  • [0004]
    2. Discussion of the Related Art
  • [0005]
    Thin films of a semiconductor device are formed by various methods including a chemical vapor deposition (CVD) method. After depositing each thin film, a chamber of a deposition apparatus is cleaned so as to remove source gases and residual products remaining on an inner wall of the chamber and in the chamber.
  • [0006]
    Perfluorocompound (PFC) gases, such as CF4, C2F6, C3F8, C4F8, and SF6, may be used as gases for removing silicon, silicon oxide (SiOX) or silicon nitride (SiNX) existing in the chamber. However, in the case of cleaning the chamber by using the PFC gases, global warming gases may be exhausted because the PFC gases may have low efficiency and may be recombined in an outlet of the chamber. The global warming gases absorb infrared (IR) rays and cause global warming. Thus, in cleaning the camber for the deposition apparatus, several methods, which use gases substituting the PFC gases or reduce quantity of the global warming gases while using the PFC gases, have been proposed.
  • [0007]
    Recently, NF3 is widely used as a cleaning gas substituting the PFC gases, and NF3 has a high cleaning rate and discharge extremely small quantities of the global warming gases. By the way, since NF3 is formed through complicated processes, NF3 is short of supply. Therefore, NF3 is provided at a high price, and raise a manufacturing cost. In addition, when the chamber for the deposition apparatus is cleaned using NF3, poisonous fluorine gas (F2) may be formed as a residual product. F2 corrodes the inner surfaces of the chamber during cleaning, and thus the apparatus for manufacturing the semiconductor device may be damaged.
  • [0008]
    Other cleaning gases have been suggested, but the cleaning gases have lower cleaning rates as compared with NF3.
  • SUMMARY OF THE INVENTION
  • [0009]
    Accordingly, the present invention is directed to a cleaning method of an apparatus for manufacturing a semiconductor device that substantially obviates one or more of problems due to limitations and disadvantages of the related art.
  • [0010]
    An advantage of the present invention is to provide a cleaning method of an apparatus for manufacturing a semiconductor device that prevents global warming.
  • [0011]
    Another advantage of the present invention is to provide a cleaning method of an apparatus for manufacturing a semiconductor device that reduces global warming gases released after cleaning the apparatus.
  • [0012]
    Another advantage of the present invention is to provide a cleaning method of an apparatus for manufacturing a semiconductor device that increases cleaning rates and improves efficiency of processing.
  • [0013]
    An advantage of the present invention is to provide a cleaning method of an apparatus for manufacturing a semiconductor device that cleans uniformly the inner side of a chamber of the apparatus.
  • [0014]
    Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
  • [0015]
    To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a cleaning method of an apparatus for manufacturing a semiconductor device includes providing a first cleaning gas and a second cleaning gas into a chamber, and forming a mixture of the first cleaning gas and the second cleaning gas, wherein the first cleaning gas includes a fluorocarbon gas and an oxygen gas and the second cleaning gas includes nitrogen, activating the mixture of the first cleaning gas and the second cleaning gas by a high frequency power, and exhausting residues cleaned by the activated mixture and remaining gases.
  • [0016]
    In another aspect of the present invention, a cleaning method of an apparatus for manufacturing a semiconductor device includes activating a first cleaning gas by a high frequency power, wherein the first cleaning gas includes a fluorocarbon gas and an oxygen gas, activating a second cleaning gas by a high frequency power, wherein the second cleaning gas includes nitrogen, mixing the activated first cleaning gas and the activated second cleaning gas, thereby forming a mixture of the first cleaning gas and the second cleaning gas, and exhausting residues cleaned by the mixtuer and remaining gases.
  • [0017]
    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
  • BRIEF DESCRIPTION OF THE DRAWING
  • [0018]
    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
  • [0019]
    In the drawings:
  • [0020]
    [0020]FIG. 1 is a schematic view showing an apparatus for manufacturing a semiconductor device used in the cleaning method according to a first embodiment of the present invention; and
  • [0021]
    [0021]FIG. 2 is a schematic view showing an apparatus for manufacturing a semiconductor device used in the cleaning method according to a fourth embodiment of the present invention.
  • DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
  • [0022]
    Reference will now be made in detail to the illustrated embodiments of the present invention, the examples of which are illustrated in the accompanying drawings.
  • [0023]
    In the present invention, a first cleaning gas and a second gas are used to clean a chamber for a deposition apparatus. The first cleaning gas includes a fluorocarbon gas and an oxygen gas and the second cleaning gas includes nitrogen. The second cleaning gas is supplied at a regular rate to the first cleaning gas.
  • [0024]
    The fluorocarbon gas, beneficially, may be one of C3F8, C4F8 and C4F8O. The fluorocarbon gas is activated to F radical by plasma, and is exhausted by reacting silicon in silicon, silicon nitride or silicon oxide remaining in the chamber and forming SiF4. Therefore, the cleaning process is performed.
  • [0025]
    The oxygen gas diffuses the fluorocarbon gas and the second cleaning gas including nitrogen. Additionally, the oxygen gas prevents the fluorocarbon gas from being a polymer such as (CF2)n and improves a cleaning rate by oxidizing residues in the chamber.
  • [0026]
    The fluorocarbon gas and the oxygen gas are supplied into the chamber or into a plasma generating system, which may be independently disposed outside the chamber, thereby forming the first cleaning gas of the present invention. The cleaning rate may increase with the addition of the fluorocarbon gas and the oxygen gas, and global warming gases released during the cleaning process are also increased. Thus, The fluorocarbon gas and the oxygen gas should be provided at an appropriate rate.
  • [0027]
    The oxygen gas should be more than the fluorocarbon gas, and beneficially, the flow rate of the fluorocarbon gas to the oxygen gas may be 0.1 to 0.5. If the fluorocarbon gas is supplied less than the above flow rate, it is hard to obtain expected cleaning effect. If the fluorocarbon gas is supplied more than the above flow rate, a proper cleaning efficiency to the increased flow cannot be achieved because the remaining time in the chamber decreases due to the increased flow.
  • [0028]
    On the other hand, as stated above, the cleaning gas of the present invention includes the second cleaning gas having nitrogen. The second cleaning gas is supplied to have a flow rate of about 0.01 to 0.5 to the first cleaning gas. If the second cleaning gas is supplied less than the above flow rate, the cleaning effect cannot be expected, and if the second cleaning gas is supplied more than the above flow rate, the cleaning rate and the decrease of the global warming effect are not effective for the increased flow rate.
  • [0029]
    The second cleaning gas may be selected from one of N2, NO and N2O. The second cleaning gas is activated to NO or NO radical by plasma, and removes nitrogen or oxygen on a surface of a film remaining in the chamber as shown in the following reaction formulas (1) to (4), thereby accelerating reaction between silicon on the surface of the film, where nitrogen or oxygen is removed, and F radical, which is formed by dissociating the fluorocarbon gas.
  • NO+Si—N(s)→Si(s)+N2O  (1)
  • N+O→NO  (2)
  • NO+Si—O(s)→Si(s)+NO2  (3)
  • NO2+O→NO+O2  (4)
  • [0030]
    In addition, the oxygen gas in the first cleaning gas and the second cleaning gas lower global warming potentials of gases emitted during the cleaning process. The fluorocarbon gas of the present invention may be recombined during the cleaning process, and forms CF4, C2F6, C3F8, C4F8, COF2, SiF4, HF, and so on.
  • [0031]
    Among the above gases including fluorine, carbon tetrafluoride (CF4), which has a high global warming potential, reacts O radical dissociated from the oxygen gas by plasma, and is changed to a gas having a low global warming potential, such as COx or COFx. Or CF4 reacts N radical dissociated from the second cleaning gas, and is changed to CN or NFx having a low global warming potential. Therefore, the cleaning gas of the present invention reduces the global warming effect due to PFC gases formed during the cleaning process of the chamber.
  • [0032]
    Destruction of feed gas and the effect of emitted gases on global warming are quantified as destructive removal efficiencies (DREs) and million metric tons of carbon equivalents (MMTCEs), respectively. DRE and MMTCE values are calculated by using the following equations (1) and (2), respectively;
  • DRE(%)=[1−C o /C i]×100,  equation (1)
  • [0033]
    where Ci is the gas volumetric concentration before the plasma cleaning and Co is the gas volumetric concentration after the plasma cleaning, and
  • MMTCE=Σ12/44×{Q(kgGWP/109},  equation (2)
  • [0034]
    where Q is the total mass of gases (in Kg) released during the cleaning process, and GWP is the global warming potential of each component (integrated over a 100 year time horizon).
  • [0035]
    Exemplary embodiments will be explained hereinafter with reference to attached drawings.
  • [0036]
    First Embodiment
  • [0037]
    [0037]FIG. 1 shows a schematic view of an apparatus for manufacturing a semiconductor device used in the cleaning method according to a first embodiment of the present invention. In the first embodiment of the present invention, a remote plasma generator 70 outside a chamber 10 is used to activate cleaning gases. One part of the remote plasma generator 70 is connected to a radio frequency (RF) power supply 20, and the other part of the remote plasma generator 70 is grounded. A gas inlet (not shown) is connected to the remote plasma generator 70. Plasma formed in the remote plasma generator 70 flows in the chamber 10 through a plasma inlet 31. A substrate holder 16 is disposed in the chamber 10, and an exhaust line 32 is connected to the chamber 10 to exhaust cleaning residues. The exhaust line 32 is also connected to a booster pump 34 and a dry pump 36, and a control valve 40 is located in the exhaust line 32. The pressure in the chamber 10 can be regulated by the control valve 40. Nitrogen gas (N2) is used as a purging gas of the dry pump 36, and a flow rate of N2 is uniformly maintained during a cleaning process. The remote plasma generator 70 may use a remote inductively couple plasma (ICP) source.
  • [0038]
    A cleaning rate of the chamber 10 is measured by a step-profilermeter 50, and a Fourier transform Infrared (FT-IR) spectrometer 60 is equipped at one end of the exhaust line 32 to measure the MMTCE of the PFC gases released during the cleaning process.
  • [0039]
    The remote plasma generator 70 uses 13.56 MHz as a RF power. During the cleaning process, RF power applied to the remote plasma generator 70 is about 500 Watts and the pressure in the chamber 10 is about 300 mTorr. Silicon nitride (not shown) is used as samples for measuring the cleaning rates of the chamber 10, and the samples are located at the center of the substrate holder 16, at the side wall of the chamber 10, and at the front wall of the chamber 10, respectively.
  • [0040]
    C4F8 is used as the fluorocarbon gas of the first cleaning gas, and N2O is used as the second cleaning gas. C4F8 of about 20 sccm and O2 of about 140 sccm are supplied into the remote plasma generator 70, because the highest cleaning rate for the silicon nitride is obtained at C4F8(20 sccm)/O2(140 sccm). The cleaning rate of C4F8/O2 without the second cleaning gas is about 110 nm/min.
  • [0041]
    N2O, as the second cleaning gas, is supplied at rates of about 0.05 to about 0.20 to the total flow of the first cleaning gas, wherein the total flow of the first cleaning gas is 160 sccm, and the cleaning rate, the DRE and the MMTCE are measured at each flow rate.
  • [0042]
    The addition of N2O to the first cleaning gas, C4F8/O2, up to the rate of about 0.05, increases the cleaning rate, and the highest cleaning rate is about 300 nm/min at the rate of about 0.05. Further additions of N2O do not particularly change the cleaning rates as compared with the cleaning rate at 0.05 N20.
  • [0043]
    There are differences in the cleaning rates at the center of the substrate holder 16, at the side wall of the chamber 10, and at the front wall of the chamber 10, and the differences in the cleaning rates are less than about 10%, thereby showing uniform cleaning rates.
  • [0044]
    The DREs of C4F8 with N2O are higher than 99%, and thus it is understood that almost all of supplied C4F8 is destructed during the cleaning process.
  • [0045]
    The PFC gases emitted during the cleaning process are measured for about 2 minutes, and the MMTCEs of the PFC gases decrease until the addition of N2O to C4F8/O2 is 0.15. Therefore, the additions of N2O to C4F8/O2 are effective in controlling the global warming effect.
  • [0046]
    Meanwhile, the MMTCEs of the PFC gases emitted while cleaning the silicon nitride of about 1,000 nm are calculated. When N2O is not added to the first cleaning gas, the MMTCE is about 1.3×10−9. When the flow rate of N2O to the first cleaning gas is about 0.05, the MMTCE decrease by about 75% as compared with the MMTCE of the case without N2O, and is about 3.5×10−10. When the flow rate of N2O to the first cleaning gas is about 0.2, the MMTCE is about 5.0×10−10.
  • [0047]
    Second Embodiment
  • [0048]
    In a second embodiment, RF power of about 800 Watts for generating plasma is applied to the remote plasma generator 70 of FIG. 1, and the pressure in the chamber 10 of FIG. 1 is about 400 mTorr. Other conditions of the second embodiment are the same as conditions of the first embodiment, and the same apparatus in the first embodiment may be used. In addition, samples for measuring cleaning rates of the chamber are located at the center of the substrate holder 16, at the side wall of the chamber 10, and at the front wall of the chamber 10, respectively.
  • [0049]
    C4F8O is used as the fluorocarbon gas of the first cleaning gas, and N2O or NO is used as the second cleaning gas. C4F8O of about 40 sccm and O2 of about 180 sccm are supplied into the remote plasma generator 70. When the second cleaning gas is not supplied, the cleaning rate is about 118 nm/min, and the DRE and the MMTCE are about 96% and about 7.023×10−10 respectively.
  • [0050]
    N2O or NO, as the second cleaning gas, is supplied at rates of about 0.05 to about 0.25 to the total flow of the first cleaning gas, respectively, wherein the total flow of the first cleaning gas is 220 sccm, and the cleaning rate, the DRE and the MMTCE are measured at each flow rate of each second cleaning gas.
  • [0051]
    In the case that the second cleaning gas is N2O, the additions of N2O to the first cleaning gas, C4F8O/O2, increase the cleaning rates, and the cleaning rate is about 1,190 nm/min at the flow rate of about 0.15. Further additions of N2O do not particularly change the cleaning rates as compared with the cleaning rate at 0.15 of N2O to the first cleaning gas. The differences in the cleaning rates at the three locations are about 13%. The DREs of C4F8O are higher than 96% without regard to additions of N2O. The MMTCE at the addition of 0.05 N2O to C4F8O/O2 decreases by about 95%. Therefore, the additions of N2O to C4F8O/O2 are effective in controlling the global warming effect.
  • [0052]
    When NO is added as the second cleaning gas to C4F8O/O2, the cleaning rate increases, and is about 1,150 nm/min at the flow rate of 0.05 NO to C4F8O/O2. Although NO is added over 0.05 of the flow rate, the cleaning rates are about the same value as the cleaning rate at 0.05 of NO to the first cleaning gas. The differences in the cleaning rates at the three locations are about 11%, and the cleaning is uniform at the three locations. The DREs of C4F8O are similar without regard to additions of NO. The MMTCE at the addition of 0.05 NO to C4F8O/O2 decreases by 93% as compared with the MMTCE when NO is not added.
  • [0053]
    Third Embodiment
  • [0054]
    In a third embodiment, RF power for generating plasma is about 300 Watts and the pressure in the chamber is about 400 mTorr. The third embodiment may use a capacitively coupled plasma (CCP) system.
  • [0055]
    Silicon nitride (5 cm×5 cm) formed on a silicon wafer is used as samples for measuring the cleaning rates of the chamber. C4F8O is used as the fluorocarbon gas of the first cleaning gas, and N2 is used as the second cleaning gas. C4F8O of about 16 sccm and O2 of about 64 sccm are supplied into the chamber. When the second cleaning gas is not supplied, the cleaning rate is about 507.7 nm/min, and the DRE and the MMTCE are about 98.38% and 3.58×10−9, respectively.
  • [0056]
    N2 is supplied as the second cleaning gas at rates of about 0.05 to about 0.20 to the total flow of the first cleaning gas, respectively, wherein the total flow of the first cleaning gas is 80 sccm, and the cleaning rate, the DRE and the MMTCE are measured at each flow rate.
  • [0057]
    The additions of N2 to the first cleaning gas, C4F8O/O2, increase the cleaning rates, and the cleaning rate is highest at the flow rate of 0.10 of N2 to C4F8O/O2. The cleaning rate at 0.10 of N2 to C4F8O/O2 increases by about 32.5% as compared with the cleaning rate when N2 is not added. Although N2 is added over the flow rate of 0.10, the cleaning rates are about the same value as the cleaning rate at 0.10 of N2 to the first cleaning gas.
  • [0058]
    The DREs of C4F8O are higher than 97% while N2 is added at the flow rates of 0.05 to 0.20 to C4F8O/O2. The MMTCE at the addition of 0.10 of N2 to C4F8O/O2 decreases by about 38.0% as compared with the MMTCE the cleaning gas without N2.
  • [0059]
    Fourth Embodiment
  • [0060]
    [0060]FIG. 2 shows a schematic view of an apparatus for manufacturing a semiconductor device used in the cleaning method according to a fourth embodiment of the present invention.
  • [0061]
    In FIG. 2, an upper electrode 12 and a lower electrode 14 are disposed in a chamber 10. The upper electrode 12 is connected to a radio frequency (RF) power supply 20 and the lower electrode 14 is grounded. A gas inlet 30 is equipped at the chamber 10, and a substrate holder 16 is disposed in the chamber 10. An exhaust line 32 is connected to the chamber 10 to exhaust cleaning residues. The exhaust line 32 is also connected to a booster pump 34 and a dry pump 36, and a control valve 40 is located in the exhaust line 32. The pressure in the chamber 10 can be regulated by the control valve 40. Nitrogen gas (N2) is used as a purging gas of the dry pump 36, and a flow rate of N2 is uniformly maintained during a cleaning process. A cleaning rate of the chamber 10 is measured by a step-profilermeter 50, and a Fourier transform Infrared (FT-IR) spectrometer 60 is equipped at one end of the exhaust line 32 to measure the MMTCE of the PFC gases released during the cleaning process. Samples for measuring the cleaning rates are located on the substrate holder.
  • [0062]
    The fourth embodiment of the present invention may use a capacitively coupled plasma (CCP) system for generating plasma. RF power of about 350 Watts is supplied and the pressure in the chamber is about 500 mTorr during the cleaning.
  • [0063]
    C4F8O is used as the fluorocarbon gas of the first cleaning gas, and N2O or NO is used as the second cleaning gas. C4F8O of about 16 sccm and O2 of about 64 sccm are supplied into the chamber 10. When the second cleaning gas is not supplied, the cleaning rate is about 600 nm/min, and the DRE and the MMTCE are about 98% and about 3.6×10−10, respectively.
  • [0064]
    N2O or NO, as the second cleaning gas, is supplied at rates of about 0.05 to about 0.25 to the total flow of the first cleaning gas, respectively, wherein the total flow of the first cleaning gas is 80 sccm, and the cleaning rate, the DRE and the MMTCE are measured at each flow rate of each second cleaning gas.
  • [0065]
    The cleaning rates are increased as N2O or NO are added to the first cleaning gas, C4F8O/O2, and particularly at flow rates of 0.05 to 0.15 to the first cleaning gas. The cleaning rates at additions of NO are higher than those at additions of N2O.
  • [0066]
    The DREs are within a range of about 95% to about 99% without regard to additions and kinds of the second cleaning gas. The additions of the second cleaning gas to C4F80/O2 decrease the MMTCEs. The MMTCE normalized to 1,000 nm/min of the cleaning rate for silicon nitride is about 5.66×10−10 when the second cleaning rate is not added. The normalized MMTCEs decrease with the additions of the second cleaning gases to the first cleaning gas, and are about 2.52×10−10 at 0.15 of NO and 3.31×10−10 at 0.15 of N2O, respectively.
  • [0067]
    Fifth Embodiment
  • [0068]
    C3F8 is used as the fluorocarbon gas of the first cleaning gas, and N2, NO, or N2O is used as the second cleaning gas. C3F8 of about 150 sccm and O2 of about 350 sccm are supplied. When the second cleaning gas is not added, the cleaning rate is about 258.9 nm/min, and the DRE and the MMTCE are about 99% and about 1.4×10−10, respectively.
  • [0069]
    In the case of N2, the cleaning rate is highest at the addition of 0.10 N2 to C3F8/O2, and is about 304.3 nm/min. In the case of NO, the cleaning rate is highest at the addition of 0.05 NO to C3F8/O2, and is about 433 nm/min. In the case of N2O, the cleaning rate is highest at the addition of 0.10 N2O to C3F8/O2, and is about 426.5 nm/min.
  • [0070]
    The DREs are about 99% without regard to additions and kinds of the second cleaning gas.
  • [0071]
    The additions of the second cleaning gases, N2, NO and N2O, to C3F8/O2 decrease the MMTCEs. The MMTCEs are rapidly decreased when the flow rate of the second cleaning gas to the first cleaning gas is 0.05, and decreased by about 30% to about 40% as compared with the values when the second cleaning gases are not added.
  • [0072]
    Sixth Embodiment
  • [0073]
    C4F8 is used as the fluorocarbon gas of the first cleaning gas, and N2, NO, or N2O is used as the second cleaning gas. C4F8 of about 100 sccm and O2 of about 400 sccm are supplied. When the second cleaning gas is not added, the cleaning rate is about 232.9 nm/min, and the DRE and the MMTCE are about 99% and about 6.15×1 0-11, respectively.
  • [0074]
    In the case of N2, the cleaning rate is highest at the addition of 0.15 N2 to C4F8/O2, and is about 333.6 nm/min. In the case of NO, the cleaning rate is highest at the addition of 0.15 NO to C4F8/O2, and is about 314.5 nm/min. In the case of N2O, the cleaning rate is highest at the addition of 0.15 N2O to C4F8/O2, and is about 307.5 nm/min.
  • [0075]
    The DREs are about 99% without regard to additions and kinds of the second cleaning gas.
  • [0076]
    The additions of the second cleaning gases, N2, NO and N2O, to C4F8/O2 decrease the MMTCEs. The MMTCEs are lowest when the second cleaning gas is added at the flow rate of 0.15 to the first cleaning gas, and decreased by about 25% to about 40% as compared with the values when the second cleaning gases are not added.
  • [0077]
    Comparison
  • [0078]
    To compare the results from the embodiments of the present invention, another cleaning process using NF3 as a cleaning gas is performed in the same conditions and the same apparatus as the first embodiment. At this time, argon gas (Ar) is added to NF3. The flow of NF3 is about 20 sccm and the flow rate of Ar mixed to NF3 is varied.
  • [0079]
    The additions of Ar to NF3 initially increase the cleaning rate, and the highest cleaning rate is about 310 nm/min at the flow rate of 0.5 Ar to NF3. Also, the differences in the cleaning rates among the three locations, that is, at the center of the substrate holder, at the side wall of the chamber, and at the front wall of the chamber, are less than 10%, thereby showing uniform cleaning rates regardless of location.
  • [0080]
    The DREs are over 99% without regard to additions of Ar, thereby showing that most of fed NF3 gas is destructed.
  • [0081]
    Also, the MMTCEs are about 0.5×10−10 without regard to additions of Ar. Meanwhile, the MMTCEs normalized to 1,000 nm/min of the cleaning rate for silicon nitride are within a range of about 10.0×10−10 to about 12.5×10−10.
  • [0082]
    As mentioned above, the cleaning method of the present invention decreases global warming gases released after cleaning process, and thus reduces global warming effect.
  • [0083]
    The cleaning method of the present invention increases cleaning rates, thereby improving processing efficiency, and the chamber is uniformly cleaned by the cleaning method of the present invention.
  • [0084]
    In addition, since the cleaning gas used in the present invention is cheaper than NF3, the manufacturing costs of the semiconductor device are decreased.
  • [0085]
    It will be apparent to those skilled in the art that various modifications and variations can be made in the fabrication and application of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
Patent Citations
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US8083862Mar 9, 2007Dec 27, 2011Tokyo Electron LimitedMethod and system for monitoring contamination on a substrate
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Classifications
U.S. Classification134/1.2
International ClassificationC23C16/44, B08B7/00, H01L21/205
Cooperative ClassificationB08B7/0035, C23C16/4405, B08B7/00, Y02C20/30
European ClassificationB08B7/00S, B08B7/00, C23C16/44A6
Legal Events
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Jan 27, 2004ASAssignment
Owner name: JUSUNG ENGINEERING CO. LTD., KOREA, REPUBLIC OF
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:YOON, SOO-SIK;YEON, GEUN-YOUNG;LEE, NAE-EUNG;AND OTHERS;REEL/FRAME:014935/0065;SIGNING DATES FROM 20040106 TO 20040120