JP2010027787A - End point detection method, substrate treatment method, substrate-treating device, and substrate treatment system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an end point detection method capable of easily, precisely, and rapidly detecting an end point when removing copper oxide by performing dry cleaning to a substrate having a copper film where the copper oxide is formed on the surface by an organic acid. <P>SOLUTION: Gas in a treatment chamber or gas discharged from the treatment chamber is analyzed during dry cleaning treatment by introducing organic acid gas into the treatment chamber, thus detecting an end point based on a change in concentration of a prescribed gas constituent when the copper oxide has been formed and when the copper oxide has been removed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an end point detection method for removing copper oxide by performing dry cleaning with an organic acid on a substrate having a copper film with copper oxide formed on the surface, and a substrate processing method including such end point detection. The present invention relates to a substrate processing apparatus having such an end point detection function and a substrate processing system having such a substrate processing apparatus.

  Recently, in response to demands for higher speeds of semiconductor devices, finer wiring patterns, and higher integration, there has been a demand for lower capacitance between wirings, improved wiring conductivity, and improved electromigration resistance. As a corresponding technology, copper (Cu), which has higher conductivity and better electromigration resistance than aluminum (Al) and tungsten (W), is used as the wiring material, and the capacitance between Cu wirings is reduced as an interlayer insulating film. As such, Cu multilayer wiring technology using a low dielectric constant film (Low-k film) has attracted attention.

  Cu is easily oxidized, and copper oxide is easily formed on the surface. Since copper oxide increases resistance, a treatment for removing it is performed. As a technique for removing copper oxide on the surface of the Cu film, organic acid dry cleaning using an organic acid such as formic acid has been proposed (for example, Non-Patent Documents 1 and 2).

  In such organic acid dry cleaning, from the viewpoint of improving the throughput of processing, it is desired to quickly detect the end point of the cleaning when the copper oxide is removed and the Cu surface is exposed.

  Although such an organic acid dry cleaning end point detection technique has not yet been established, the following three methods are conceivable.

  The first method is to measure the copper oxide film thickness by ellipsometry after exposing the wafer after dry cleaning to the atmosphere (for example, Patent Document 1).

  The second is a method of measuring the copper oxide film thickness and the copper surface composition by attaching an in-situ measuring device for analyzing the copper surface to the processing device (for example, Non-Patent Document 3).

  The third method is to form a cap film such as a barrier metal on the copper surface after dry cleaning in-situ, and analyze the interface between copper and the cap film (for example, Non-Patent Document 4).

  However, since the first method is measurement after exposure to the atmosphere, even if the copper oxide can be removed at the end of the process, it must be measured in a state where the copper surface is naturally oxidized. Strictly speaking, it is not possible to confirm the state in which the metallic copper is exposed.

  In the second method, it is difficult to confirm the in-plane uniformity of dry cleaning on a large-diameter substrate such as a 300 mm wafer.

In the third method, it is necessary to perform the interface analysis by transmission electron microscope (TEM) observation of a cross section, secondary ion mass spectrometry (SIMS), or the like, and it takes time until a measurement result is obtained.
JP 2007-40930 A Kenji Ishikawa and 3 others, “Examination of dry cleaning of Cu surface -Supply steam composition and flow rate control-”, Proceedings of the 67th Japan Society of Applied Physics (Ritsumeikan University Fall, 2006), 31a-ZN-7, p754 Masakazu Hayashi and three others, “Examination of dry cleaning of Cu surface: generation of volatile molecules by organic acid vapor”, Proceedings of the 67th JSAP Academic Lecture Meeting (Autumn 2006 Ritsumeikan University), 31a- ZN-8, p754 A. Satta et al., J. Electrochem. Soc. 150 (5) G300 (2003) J. Nakahira et al., Proc. AdvancedMetallization Conference 2005 p569 (2006)

  The present invention has been made in view of such circumstances, and when the substrate having a copper film with copper oxide formed on the surface is subjected to dry cleaning with an organic acid to remove the copper oxide, the end point thereof An end point detection method capable of quickly and accurately detecting an end point, a substrate processing method including such an end point detection, a substrate processing apparatus having an end point detection function, and such a substrate processing apparatus An object is to provide a substrate processing system. Furthermore, it aims at providing the storage medium which memorize | stored the program for implementing such an end point detection method and a substrate processing method.

  In order to solve the above-mentioned problem, in the first aspect of the present invention, end point detection when removing copper oxide by performing dry cleaning with an organic acid on a substrate having a copper film with copper oxide formed on the surface thereof. In this method, the organic acid gas is introduced into the processing chamber and the dry cleaning process is performed to analyze the gas in the processing chamber or the gas discharged from the processing chamber, and copper oxide is formed on the substrate. An end point detection method is provided, wherein the end point is detected based on a change in concentration of a predetermined gas component between when the copper oxide is removed and when the copper oxide is removed.

  In the second aspect of the present invention, the step of accommodating a substrate having a copper film with copper oxide formed on the surface thereof in a processing chamber, the step of introducing an organic acid into the processing chamber, the heating the substrate while the substrate is heated The process of removing the copper oxide by performing dry cleaning with the introduced organic acid, and the organic acid gas introduced into the processing chamber and exhausted from the processing chamber or the processing chamber when performing the dry cleaning process Analyzing the gas, detecting the end point based on the concentration change of a predetermined gas component when the copper oxide is formed on the substrate and when the copper oxide is removed, and the organic acid gas after the end point is detected And a substrate processing method including a step of stopping the introduction of the substrate.

In the first and second aspects, formic acid is used as the organic acid, based on the change in the concentration of CO ₂ or H _{2 in} the processing chamber when copper oxide is formed and when copper oxide is removed. To detect the end point.

  As the substrate, there can be used a copper film as a wiring layer and a cap film formed thereon, and the cap film is plasma-etched up to the copper film. It is also possible to use one having a copper film embedded so that the surface is exposed inside.

  In a third aspect of the present invention, a processing chamber that houses a substrate having a copper film with copper oxide formed on the surface, an organic acid gas supply means that supplies an organic acid gas to the processing chamber, and a processing chamber. A support member for supporting the substrate, a heating means for heating the substrate supported by the support member, an exhaust means for exhausting the processing chamber, and a gas in the processing chamber or a gas exhausted from the processing chamber are collected. Gas sampling means, gas analysis means for analyzing the collected gas, and predetermined gas measured by the gas analysis means when the copper oxide is formed on the substrate and when the copper oxide is removed Provided is a substrate processing apparatus having an end point detecting function, characterized by comprising end point detecting means for detecting an end point based on a concentration change of a component.

  In the third aspect, the organic acid gas supply means that supplies formic acid gas may be used, and the end point detection means may detect the end point based on a change in the concentration of carbon dioxide or hydrogen.

  Further, the gas sampling means can be configured to have a gas sampling pipe connected to the processing chamber, and have a configuration including a gas sampling pipe connected to an exhaust pipe connected to the processing chamber. You can also.

  Further, as the gas analyzing means, a mass spectrometer, an infrared spectrometer, a gas chromatography, or a device having a constant potential electrolytic gas sensor can be used. Furthermore, the heating means may include a heater provided on the support member.

  According to a fourth aspect of the present invention, there is provided a substrate processing apparatus according to the third aspect, and a method of forming a predetermined film on the copper film of the substrate from which the oxide film on the copper film has been removed by the substrate processing apparatus. There is provided a substrate processing system comprising: a film apparatus; and a substrate transport mechanism that transports the substrate without being exposed to the atmosphere to the substrate processing apparatus and the film forming apparatus.

  According to a fifth aspect of the present invention, there is provided a storage medium that operates on a computer and stores a program for controlling a substrate processing apparatus, and the program is executed by the end point detection method according to the first aspect. As described above, there is provided a storage medium that causes a computer to control the substrate processing apparatus.

  According to a sixth aspect of the present invention, there is provided a storage medium that operates on a computer and stores a program for controlling a substrate processing apparatus, and the program is executed by the substrate processing method according to the second aspect. As described above, there is provided a storage medium that causes a computer to control the substrate processing apparatus.

  According to the present invention, the copper oxide is formed by analyzing the gas in the processing chamber or the gas discharged from the processing chamber when the organic acid gas is introduced into the processing chamber to perform the dry cleaning process. Since the end point is detected based on the change in the concentration of the predetermined gas component between when the copper oxide is removed and when the copper oxide is removed, the end point can be detected quickly in real time in-situ. Further, the concentration of a predetermined gas component in the processing chamber may be measured, and the end point can be detected easily and with high accuracy. Further, since the end point can be detected quickly in real time in this way, the processing throughput can be improved by stopping the dry cleaning immediately when the end point is detected.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram showing an example of a dry cleaning apparatus to which the end point detection method of the present invention can be applied.

  The dry cleaning apparatus 100 includes a chamber 1 that can hold a wafer W and can be held in a vacuum, a formic acid supply mechanism 2 that supplies formic acid vapor that is an organic acid into the chamber 1, and a nitrogen gas or an argon gas, for example, as a dilution gas. 1 is provided with a dilution gas supply mechanism 3 for supplying the inside of the chamber 1 and an exhaust mechanism 4 for evacuating the inside of the chamber 1.

  At the bottom of the chamber 1, a mounting table 5 for mounting the accommodated wafer W is provided. Inside the mounting table 5, a heater 6 for heating the wafer W is provided. A loading / unloading port 7 for loading / unloading the wafer W is formed on the side wall of the chamber 1, and the loading / unloading port 7 is opened and closed by a gate valve 8.

  A shower head 10 is provided on the upper portion of the chamber 1 so as to face the mounting table 5. The shower head 10 has a diffusion space 11 for diffusing the formic acid (HCOOH) supplied from the formic acid supply mechanism 2 and the dilution gas supplied from the dilution gas supply mechanism 3 inside, and on the surface facing the mounting table 5, A plurality of discharge holes 12 for discharging formic acid vapor or dilution gas into the chamber 1 are formed.

  An exhaust port 9 is formed in the bottom wall of the chamber 1. The exhaust mechanism 4 includes an exhaust pipe 16 connected to the exhaust port 9 and a vacuum pump 17 that exhausts the inside of the chamber 1 through the exhaust pipe 16. And a pressure adjusting valve 18 provided in the exhaust pipe 16.

  The formic acid supply mechanism 2 includes a formic acid storage unit 21 in which liquid formic acid is stored, a heater 22 for vaporizing the formic acid in the formic acid storage unit 21, and a diffusion space 11 of the showerhead 10 with the vaporized formic acid. A formic acid vapor supply line 23 that leads to the inside, a mass flow controller 24 as a flow rate adjusting mechanism that adjusts the flow rate of the formic acid vapor that flows through the formic acid vapor supply line 23, and an open / close valve 25 that opens and closes the formic acid vapor supply line 23. ing.

  The dilution gas supply mechanism 3 includes a dilution gas supply source 26 that supplies a dilution gas such as nitrogen gas and argon gas, a dilution gas supply line 27 that guides the dilution gas into the diffusion space 11 of the shower head 10, and a dilution gas supply line. A mass flow controller 28 serving as a flow rate adjusting mechanism for adjusting the flow rate of nitrogen gas flowing through 27, and an open / close valve 29 for opening and closing the dilution gas supply line 27.

  A gas sampling port 31 is provided in the chamber 1, and a gas sampling pipe 32 is connected to the gas sampling port 31. A gas analyzer 33 is provided at the end of the gas sampling pipe 32. The gas sampling pipe 32 is provided with a valve 34. As the gas analyzer 33, one capable of measuring a gas component and its concentration is used. For example, a mass spectrometer such as a quadrupole mass spectrometer (Q-Mass), an IR (infrared spectrometer), a gas Chromatography, a constant potential electrolytic gas sensor, etc. can be used. A constant potential electrolytic gas sensor is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-214190.

  The dry cleaning apparatus 100 includes a control unit 40, and the control unit 40 includes a process controller 41, a user interface 42, and a storage unit 43. The process controller 41 is connected to each component of the dry cleaning apparatus 100, such as the mass flow controllers 24 and 28, valves 25 and 29, the vacuum pump 17, the pressure adjusting valve 18, the heaters 6 and 22, the gas analyzer 33, and the like. These are controlled by the process controller 41.

  The user interface 42 is connected to the process controller 41, and includes a keyboard on which an operator inputs commands to manage the processing apparatus, a display that visualizes and displays the operating status of the plasma processing apparatus, and the like.

  The storage unit 43 is connected to the process controller 41, and is stored in a control program for realizing various processes executed by the processing device under the control of the process controller 41 and each component of the processing device according to processing conditions. A program for executing the process, that is, a recipe is stored. The recipe is stored in a storage medium in the storage unit 43. The storage medium may be a fixed medium such as a hard disk or a portable medium such as a CDROM, DVD, or flash memory. Moreover, you may make it transmit a recipe suitably from another apparatus via a dedicated line, for example.

  Then, if necessary, an arbitrary recipe is called from the storage unit 43 by an instruction from the user interface 42 and is executed by the process controller 41, so that a desired process in the processing device is controlled under the control of the process controller 41. Is done.

  In the present embodiment, the process controller 41 has a function of receiving the measurement result from the gas analyzer 33 and detecting the end point of the dry cleaning with formic acid based on the measurement result as will be described later.

  Next, a dry cleaning procedure including end point detection in the processing apparatus configured as described above will be described.

Here, as shown in FIG. 2, an upper interlayer insulating film 102 is formed on the lower interlayer insulating film 101, and a position corresponding to the Cu film 103 which is a wiring layer provided on the lower interlayer insulating film 101. Then, the copper oxide 107 formed on the surface of the Cu film 103 is removed from the wafer W in which the trench 104 and the hole 105 are formed in the upper interlayer insulating film 102 by plasma etching. Examples of the interlayer insulating film include a SiO ₂ film and a low-k film. Reference numeral 106 denotes a cap film, specifically a barrier insulating film.

  First, with the gate valve 8 opened, the wafer W having the above-described configuration is loaded into the chamber 1 from the loading / unloading port 7 by a transfer device (not shown), placed on the mounting table 5, and then the gate valve 8 is closed. The chamber 1 is sealed. The wafer W on the mounting table 5 is heated by the heater 6 to a predetermined temperature, preferably a temperature in the range of 100 to 400 ° C.

Then, the inside of the chamber 1 is adjusted to a predetermined degree of vacuum by the exhaust mechanism 4, and formic acid vapor is supplied into the chamber 1 together with the dilution gas. The formic acid vapor supplied into the chamber 1 causes a reaction of the following formula (1) with the copper oxide film 107 existing on the heated wafer W to remove the copper oxide film 107.
Cu ₂ O + 2HCOOH → 2Cu (HCOO) ↑ + H ₂ O ↑ (1)

When the removal reaction of the copper oxide film 107 proceeds in this way and the Cu film 103 is exposed, the supplied formic acid vapor is decomposed into carbon dioxide and hydrogen as shown in the following equation (2).
HCOOH → CO ₂ + H ₂ (2)

This is described in Non-Patent Document 5 (K. Ishikawa et al., Mat. Res. Soc. Symp.
Proc. 766 p.459 (2003)). This document shows the results of research on the mechanism of cleaning the Cu surface using organic acid vapor, and formic acid gas is supplied for a long time to the copper oxide actually formed on the copper surface. In this non-patent document 5, it is shown that carbon dioxide is generated in the gas phase when the formic acid vapor exposure is continued even after the copper oxide removal reaction is completed and the metal copper is exposed. 4, and described in FIG. A drawing corresponding to 4 is shown in FIG.

FIG. 3 is a diagram showing an infrared reflection absorption spectroscopy (IR-RAS) spectrum every 90 seconds when formic acid vapor is exposed to a sample heated to 190 ° C., and Cu ₂ O with the passage of time. It can be seen that the peak of decreases and the peak of CO ₂ increases. This is considered to be a result of decomposition of formic acid according to the formula (2) by the catalytic action of metallic copper.

  On the other hand, when formic acid vapor is supplied onto the heated copper oxide surface, carbon dioxide and hydrogen may be produced when copper oxide is reduced or etched by chemical reaction with formic acid, but the amount is large. Absent. In fact, in FIG. 3, the generation of carbon dioxide cannot be confirmed at the stage where copper oxide is present immediately after the start of formic acid supply.

  That is, when formic acid is supplied onto the heated copper oxide surface, the above formula (2) hardly proceeds, and the amount of carbon dioxide or hydrogen generated from formic acid is small, whereas the heated metal oxidation When formic acid is supplied onto the copper surface, the formula (2) proceeds and a large amount of carbon dioxide and hydrogen generated from formic acid are generated. Therefore, by utilizing this fact, it is possible to detect that the copper oxide is removed and the surface of the metal copper is exposed, and thereby it is possible to detect the end point of the dry cleaning.

  Specifically, when the metallic copper is exposed and the formic acid vapor is decomposed to generate carbon dioxide and hydrogen, the concentrations of carbon dioxide and hydrogen in the chamber 1 change. To the gas analyzer 33 through the gas sampling pipe 32 to measure the carbon dioxide concentration or the hydrogen concentration in real time, and the end point is detected from the concentration change. In other words, since the carbon dioxide concentration and the hydrogen concentration increase when the copper oxide is removed and the copper metal is exposed, it is determined that the dry cleaning has reached the end point when the carbon dioxide concentration or the hydrogen concentration increases by a predetermined amount. The supply of formic acid vapor is stopped and the process is terminated.

As described above, the gas analyzer 33 may be any device that can measure gas components and their concentrations. For example, a mass spectrometer such as a quadrupole mass spectrometer (Q-Mass), IR (red) Various types such as an external spectrometer) and gas chromatography can be used. However, when IR is used, hydrogen cannot be detected, so carbon dioxide is measured. Moreover, since it is difficult for Q-Mass to distinguish the CO ₂ peak from other peaks, it is desirable to measure hydrogen.

  In this way, the concentration of carbon dioxide or hydrogen can be measured in-situ in real time by the gas analyzer 33 during dry cleaning with formic acid, and changes in these concentrations at the time when the metallic copper is exposed. Since the end point of the dry cleaning is detected only by grasping the above, it is possible to detect it easily, with high accuracy and quickly. In addition, since the end point can be detected quickly in real time in this way, the processing throughput can be improved by stopping the dry cleaning immediately when the end point is detected.

  For the wafer W after the dry cleaning is completed in this way, after the barrier layer 108 and the Cu seed layer 109 are formed on the side walls and the bottom of the via 105 and the trench 104 as shown in FIG. Cu is buried in the via 105 and the trench 104 by plating. In this case, when the barrier layer 108 and the Cu seed layer 109 are formed after the copper oxide 107 is removed by dry cleaning and then exposed to the atmosphere, the copper is oxidized again. There is a concern that it will be.

  From the viewpoint of preventing this, it is preferable to form the barrier layer 108 and the Cu seed layer 109 without exposure to the atmosphere after dry cleaning using a cluster type processing system as shown in FIG.

  The processing system 200 of FIG. 5 includes a dry cleaning unit 51 having the same configuration as the dry cleaning 100, a barrier layer forming unit 52 that forms a barrier layer 108 by sputtering, and a seed that forms a Cu seed layer 109 by sputtering. The layer forming unit 53 is provided, and these units 51, 52, 53 are respectively provided corresponding to two sides of the octagonal transfer chamber 55. Load lock chambers 56 and 57 are provided on the other two sides of the transfer chamber 55, respectively. A load / unload chamber 58 is provided on the opposite side of the load lock chambers 56 and 57 from the transfer chamber 55, and a semiconductor wafer W as a substrate to be processed is provided on the opposite side of the load lock chambers 56 and 57 of the load / unload chamber 58. Are provided with ports 59, 60, and 61 for attaching three carriers C capable of accommodating the.

  The inside of the transfer chamber 55 and the units 51, 52, 53 is kept in a vacuum atmosphere, and the carry-in / out chamber 58 is kept in an air atmosphere. Further, the load lock chambers 56 and 57 can be switched between an air atmosphere and a vacuum atmosphere.

  As shown in the figure, the dry cleaning unit 51, the barrier layer forming unit 52, and the seed layer forming unit 53 are connected to each side of the transfer chamber 55 via the gate valve G, and these correspond to the corresponding gate valve G. Is opened to communicate with the transfer chamber 55, and the corresponding gate valve G is closed to shut off the transfer chamber 55. The load lock chambers 56 and 57 are connected to corresponding sides of the transfer chamber 55 via the first gate valve G1, and are connected to the loading / unloading chamber 58 via the second gate valve G2. . The load lock chambers 56 and 57 are communicated with the transfer chamber 55 by opening the first gate valve G1, and are blocked from the transfer chamber by closing the first gate valve G1. The second gate valve G2 is opened to communicate with the loading / unloading chamber 58, and the second gate valve G2 is closed to shut off the loading / unloading chamber 58.

  In the transfer chamber 55, a transfer device 62 that loads and unloads the wafer W with respect to the units 51, 52, 53 and the load lock chambers 56, 57 is provided. The transfer device 62 is disposed substantially at the center of the transfer chamber 55, and has two support arms 64a and 64b that support the wafer W at the tip of a rotatable / extensible / retractable portion 63 that can be rotated and extended. These two support arms 64a and 64b are attached to the rotation / extension / contraction section 63 so as to face in opposite directions.

  Three ports 59, 60, 61 for attaching a FOUP (Front Opening Unified Pod) which is a wafer storage container of the loading / unloading chamber 58 are provided with shutters (not shown), respectively. A wafer h is accommodated or directly attached in a state where an empty hoop F is placed on the stage S, and when attached, the shutter is released so as to communicate with the loading / unloading chamber 58 while preventing the entry of outside air. It has become. An alignment chamber 65 is provided on the side surface of the loading / unloading chamber 58, where the wafer W is aligned.

  In the loading / unloading chamber 58, a transfer device 66 for loading / unloading the wafer W into / from the FOUP F and loading / unloading the wafer W into / from the load lock chambers 56 and 57 is provided. The transfer device 66 has an articulated arm structure, and can run on the rail 68 along the direction in which the hoops F are arranged. The wafer W is placed on the support arm 67 at the tip thereof and transferred. I do.

  The processing system 200 includes a control unit 70, and each component of the processing system 200 is controlled by the control unit 70. The control unit 70 is configured in the same manner as the control unit 40.

  In the processing system 200 configured as described above, the wafer W is taken out from one of the FOUPs F by the transfer device 66 and loaded into the load lock chamber 56 or 57, and the transfer device 62 transfers the wafer W from the load lock chamber 56 or 57. To 55. First, dry cleaning with formic acid is performed in the dry cleaning unit 51 to remove the copper oxide 107 formed on the Cu film 103 of the wafer W.

  Next, the wafer W is taken out from the dry cleaning unit 51 by the transfer device 62 and loaded into the barrier layer forming unit 52, and the barrier layer 108 is formed by sputtering.

  Thereafter, the wafer W is taken out from the barrier layer forming unit 52 by the transfer device 62 and loaded into the seed layer forming unit 53, and the Cu seed layer 109 is formed on the barrier layer 108.

  Thereafter, the wafer W is transferred to the load lock chamber 56 or 57 by the transfer device 62, and after returning to the atmospheric pressure, the wafer W is transferred into a predetermined FOUP F by the transfer device 66. Such a series of processing is continuously performed on the number of wafers W accommodated in the FOUP F.

  In the processing system 200, since the dry cleaning, the formation of the barrier layer 108, and the formation of the Cu seed layer 109 are performed without being exposed to the atmosphere in this way, the barrier layer is hardly formed after the dry cleaning. 108 or the like can be formed. Therefore, the end point detection method of this embodiment is particularly effective when applied to the dry cleaning unit 51 incorporated in such a cluster type processing system 200.

  After the Cu seed layer 109 is formed, the wafer W is taken out of the processing system 200 and transferred to the plating apparatus, so that it is exposed to the atmosphere. However, since copper oxide is reduced during plating, there is almost no adverse effect. .

  Cu embedding can also be performed by CVD (Chemical Vapor Deposition). In this case, the Cu embedded unit can be mounted on a cluster type processing system. When Cu is buried by CVD, the Cu seed layer may be omitted and Cu may be buried directly on the barrier layer 108.

  In the above description, the case where the copper oxide 107 formed after etching the interlayer insulating film 102 on the Cu film 103 is removed has been described. However, as shown in FIG. 6, the barrier insulating film 106 is formed on the Cu film 103. Since the Cu film 103 is oxidized to form the copper oxide 107 ′ before forming the film, dry cleaning is performed at this stage, and the end point can be detected by the same method.

  In the case of this example, after removing the copper oxide 107 ′, as shown in FIG. 7, a barrier insulating film 106 and a low-k film 102 are formed. There is also concern that copper will be oxidized again.

  Therefore, even in such a case, the cluster type processing system as shown in FIG. 5 is used, and instead of the barrier layer forming unit 52 and the seed layer forming unit 53, the barrier insulating layer forming unit and the low-k film forming are performed. It is preferable to mount the unit and form the barrier insulating layer 106 and the low-k film 102 without exposure to the atmosphere following the removal of the copper oxide 107 ′ by dry cleaning.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. For example, in the above-described embodiment, an example in which gas is directly collected from the chamber 1 is shown. However, as shown in FIG. 8, the gas discharged from the chamber 1 to the exhaust pipe 16 is collected through the gas collection pipe 32 ′. It may be guided to the gas analyzer 33 '. Further, in the example of FIG. 8, the gas is collected from the exhaust pipe 16 on the upstream side of the vacuum pump 17, but may be on the downstream side of the vacuum pump 17 as shown in FIG. 9.

  In the above-described embodiment, the case where formic acid is used as the organic acid has been described as an example. However, the present invention is not limited to this, and a predetermined gas component is used when copper oxide is formed and when copper oxide is removed. Applicable to all organic acids in which concentration changes occur. Moreover, although the method of evaporating by heating was used as a method for vaporizing the organic acid, other vaporization methods such as bubbling may be employed.

  Furthermore, although the case where the barrier insulating film is used as the cap film has been described as an example, a cap metal film or CuSiN film selectively grown on Cu may be used.

  Furthermore, in the above-described embodiment, the case where a semiconductor wafer is used as the substrate has been described as an example. However, other substrates such as an FPD glass substrate can also be applied.

The schematic block diagram which shows an example of the dry cleaning apparatus which can apply the end point detection method of this invention. FIG. 2 is a cross-sectional view illustrating a structure example of a wafer on which dry cleaning is performed in the dry cleaning apparatus of FIG. Shows formate infrared reflection absorption spectroscopy (IR-RAS) changes over time of the peak of Cu 2 _O peaks and CO ₂ in the spectrum when subjected to dry cleaning using. Sectional drawing for demonstrating the process after dry-cleaning the wafer of FIG. The schematic block diagram which shows the cluster type processing system which can prevent reoxidation of Cu film | membrane. Sectional drawing which shows the other structural example of the wafer in which dry cleaning is performed in the dry cleaning apparatus of FIG. Sectional drawing for demonstrating the process after dry-cleaning the wafer of FIG. Sectional drawing which shows a part of modification of the dry cleaning apparatus of FIG. Sectional drawing which shows a part of other modification of the dry cleaning apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Chamber 2; Organic acid supply mechanism 4; Exhaust mechanism 5; Mounting stand 6; Heater 7; Carry-in / out port 10; Shower head 32, 32 '; Gas sampling piping 33, 33'; Gas analyzer 40, 70; 51; Dry cleaning unit 52; Barrier layer forming unit 53; Seed layer forming unit 55; Transfer chamber 56, 57; Load lock chamber 58; Loading / unloading chamber 62, 66; Transfer device 100; Dry cleaning device 103; Cu film 107, 107 '; Copper oxide 200; Substrate processing system G; Gate valve W; Semiconductor wafer

Claims (17)

An end point detection method for removing copper oxide by performing dry cleaning with an organic acid on a substrate having a copper film with copper oxide formed on the surface,
Analysis of the gas in the processing chamber or the gas discharged from the processing chamber when the organic acid gas is introduced into the processing chamber and performing the dry cleaning process, and when the copper oxide is formed on the substrate and the copper oxide A method for detecting an end point, wherein the end point is detected based on a change in concentration of a predetermined gas component when the gas is removed. The organic acid is formic acid, and an end point is detected based on a change in the concentration of CO ₂ or H _{2 in} the processing chamber when copper oxide is formed and when the copper oxide is removed. The end point detection method according to 1.   2. The substrate according to claim 1, wherein the substrate has a copper film as a wiring layer and a cap film formed thereon, and the cap film is plasma-etched up to the copper film. The end point detection method according to claim 2.   The end point detection method according to claim 1, wherein the substrate has a copper film embedded in an insulating film so that a surface is exposed. A step of accommodating a substrate having a copper film with copper oxide formed on the surface in a processing chamber;
Introducing an organic acid into the processing chamber;
Performing a dry cleaning with the introduced organic acid while heating the substrate to remove copper oxide;
Analysis of the gas in the processing chamber or the gas discharged from the processing chamber when the organic acid gas is introduced into the processing chamber to perform the dry cleaning process, and the oxidation is performed when copper oxide is formed on the substrate. Detecting an end point based on a change in concentration of a predetermined gas component when copper is removed;
And a step of stopping the introduction of the organic acid gas after the end point is detected. The organic acid is formic acid, and an end point is detected based on a change in the concentration of CO ₂ or H _{2 in} the processing chamber when copper oxide is formed and when the copper oxide is removed. 5. The substrate processing method according to 5.   6. The substrate according to claim 5, wherein the substrate includes a copper film as a wiring layer and a cap film formed thereon, and the cap film is plasma-etched up to the copper film. The substrate processing method according to claim 6.   The substrate processing method according to claim 5, wherein the substrate has a copper film embedded in the insulating film so that the surface is exposed. A processing chamber containing a substrate having a copper film with copper oxide formed on the surface;
An organic acid gas supply means for supplying an organic acid gas to the processing chamber;
A support member for supporting the substrate in the processing chamber;
Heating means for heating the substrate supported by the support member;
Exhaust means for exhausting the processing chamber;
Gas collecting means for collecting the gas in the processing chamber or the gas discharged from the processing chamber;
Gas analyzing means for analyzing the collected gas;
And an end point detecting means for detecting an end point based on a change in concentration of a predetermined gas component between when the copper oxide is formed on the substrate and when the copper oxide is removed, measured by the gas analyzing means. A substrate processing apparatus having an end point detection function.   The substrate processing apparatus according to claim 9, wherein the organic acid gas supply unit supplies formic acid gas, and the end point detection unit detects an end point based on a change in the concentration of carbon dioxide or hydrogen.   The substrate processing apparatus according to claim 9, wherein the gas sampling unit includes a gas sampling pipe connected to the processing chamber.   The said exhaust means has an exhaust pipe connected to the said processing chamber, The said gas collection means has gas collection piping connected to the said exhaust pipe, The Claim 9 or Claim 10 characterized by the above-mentioned. Substrate processing equipment.   The substrate processing apparatus according to claim 9, wherein the gas analysis unit includes a mass spectrometer, an infrared spectrometer, a gas chromatography, or a constant potential electrolytic gas sensor.   The substrate processing apparatus according to claim 9, wherein the heating unit includes a heater provided on the support member. The substrate processing apparatus according to any one of claims 9 to 14,
A film forming apparatus for forming a predetermined film on the copper film of the substrate from which the oxide film on the copper film has been removed by the substrate processing apparatus;
A substrate processing system comprising: the substrate processing apparatus; and a substrate transport mechanism that transports the substrate without exposing the film forming apparatus to the atmosphere.   A storage medium that operates on a computer and stores a program for controlling the substrate processing apparatus, the computer executing the end point detection method according to any one of claims 1 to 4 at the time of execution. A storage medium that controls the substrate processing apparatus. A storage medium that operates on a computer and stores a program for controlling a substrate processing apparatus, wherein the program executes the substrate processing method according to any one of claims 5 to 8 when executed. A storage medium that controls the substrate processing apparatus.

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