JP5188212B2 - Dry cleaning method, substrate processing apparatus, and storage medium - Google Patents

Description

The present invention relates to a dry cleaning method , a substrate processing apparatus, and a storage medium for dry cleaning a surface of a substrate such as a semiconductor wafer.

  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 than aluminum (Al) and tungsten (W) and has excellent electromigration resistance, is used as a wiring material, and a low dielectric constant film (Low-k) is used as an interlayer insulating film. Cu multilayer wiring technology using a film) has attracted attention.

  Since Cu is easily oxidized and a problem arises in that it is difficult to make a contact because a copper oxide having a high resistance is easily formed on the surface, it is necessary to remove the oxide film formed on the Cu surface.

  As a method for removing the oxide film on the Cu surface, dry cleaning using plasma has been used. However, if plasma is used, the underlying Cu may be damaged. As methods for dry cleaning the substrate surface, organic acid dry cleaning (for example, Patent Document 1), hydrogen annealing (for example, Patent Document 2), carbon monoxide annealing (for example, Patent Document 2), and the like have been studied.

  On the other hand, an oxide film is likely to be formed on the silicon wafer surface or the silicide surface formed on the silicon wafer, and in this case as well, there is a problem that it becomes difficult to make contact due to the formation of the oxide film. It is necessary to remove the oxide film formed in step (b).

  A method for removing the silicon oxide film is called COR (Chemical Oxide Removal), in which a reaction product is formed by adsorbing HF gas or the like on the surface of the silicon oxide film, and then the reaction product is vaporized by high-temperature annealing. A method has been proposed (Patent Document 3).

  However, the conventional dry cleaning method for a copper oxide film generally ensures the reactivity of the substrate surface by heating the substrate from the back side of the substrate (semiconductor wafer), as shown in Patent Documents 1 to 3 above. In addition, since it is necessary to heat the substrate to at least about 150 ° C. or more, there is a concern that the Low-k film may be deteriorated or adversely affected by thermal stress on the Cu / Low-k film. In addition, the oxide film removal reaction only needs to occur on the extreme surface of the substrate, but there is a problem that the entire substrate needs to be heated and energy efficiency is poor.

In the case of COR, since the chamber for adsorbing HF gas or the like and the high temperature annealing are generally performed in separate chambers, the apparatus installation area becomes large, and the substrate is transferred between these chambers. A complicated transport mechanism is required. In addition, during the high temperature annealing, the substrate is also heated from the back side of the substrate, and there is a concern about the thermal effect on the substrate.
JP 2003-218198 A JP-A-6-97160 JP 2005-39185 A

The present invention has been made in view of such circumstances, and does not adversely affect the substrate due to heat. The substrate can be efficiently heated to perform dry cleaning of the substrate surface, and does not cause problems on the apparatus. It is an object to provide a cleaning method, a substrate processing apparatus, and a storage medium that allows the substrate processing apparatus to execute the dry cleaning method .

In order to solve the above problems, according to a first aspect of the present invention, there is provided a dry cleaning method for placing a substrate on a mounting table provided in a processing chamber capable of evacuation under reduced pressure, and dry-cleaning the surface of the substrate. Introducing a cleaning gas into the chamber and adsorbing the cleaning gas onto the substrate; and after adsorbing the cleaning gas onto the substrate, an energy medium gas to which thermal energy is applied is introduced into the processing chamber; by supplying heat energy from the medium gas to the cleaning gas adsorbed on the substrate, to provide a dry cleaning method which comprises a step of advancing the cleaning reaction with the substrate surface.

  In the first aspect, the method may further include a step of purging the processing chamber by introducing a purge gas into the processing chamber between the introduction of the cleaning gas and the introduction of the energy medium gas. A step of adsorbing the cleaning gas onto the substrate; a step of introducing the energy medium gas into the processing chamber to advance a cleaning reaction; and a step of purging the processing chamber by introducing a purge gas into the processing chamber. It is also possible to carry out alternately with a gap between them.

  Further, the energy medium gas may be given thermal energy immediately before being supplied to the substrate in the processing chamber. The cleaning gas may be supplied such that a gas flow parallel to the substrate placed on the mounting table is formed. The energy medium gas may be supplied so that a gas flow perpendicular to the substrate placed on the mounting table is formed. Furthermore, an inert gas can be used as the energy medium gas.

In the first aspect , the cleaning gas may react with an oxide film or organic contaminant on the substrate to remove them. The cleaning reaction is preferably allowed to proceed at a temperature of 80 to 300 ° C. Furthermore, the pressure in the processing chamber may be increased before the energy medium gas is introduced into the processing chamber.

In a second aspect of the present invention, a processing chamber that accommodates a substrate and performs a cleaning process and that can be evacuated under reduced pressure , a mounting table on which the substrate is mounted in the processing chamber, and a cleaning that introduces a cleaning gas into the processing chamber A gas introduction mechanism, an energy medium introduction mechanism for introducing an energy medium gas to which thermal energy is given into the processing chamber, an exhaust mechanism for exhausting the processing chamber, and a substrate surface by introducing the cleaning gas into the processing chamber after adsorbing the cleaning gas, introducing the energy medium gas into the processing chamber, by supplying heat energy to the cleaning gas adsorbed on the substrate from the energy medium gas cleaning reaction at the substrate surface And a control mechanism for controlling to advance the substrate. A substrate processing apparatus is provided.

In the second aspect , the cleaning gas introduction mechanism and the exhaust mechanism introduce and exhaust the cleaning gas so that a gas flow parallel to the substrate placed on the mounting table is formed. can do. Further, the energy medium introduction mechanism and the exhaust mechanism can introduce and exhaust the energy medium gas so that a gas flow perpendicular to the substrate placed on the mounting table is formed. . In this case, the energy medium introduction mechanism may include a shower head that discharges the energy medium gas into the processing container. In addition, the energy medium introduction mechanism may include a heater that applies thermal energy to the energy medium gas provided in the shower head. Furthermore, the pressure in the processing chamber may be increased before the energy medium gas is introduced into the processing chamber.

In a third aspect of the present invention operates on a computer, a storage medium storing a program for controlling the processor, the program, when executed, dry cleaning method of the first viewpoint row A storage medium characterized by causing a computer to control a processing device is provided.

According to the present invention, after introducing a cleaning gas into the processing chamber and adsorbing the cleaning gas onto the substrate, an energy medium gas to which thermal energy is applied is introduced into the processing chamber, and the substrate is extracted from the energy medium gas. By supplying thermal energy to the cleaning gas adsorbed on the substrate and causing the cleaning reaction to proceed on the substrate surface, only the surface of the substrate that needs to be cleaned is heated, and the adverse effects on the substrate can be extremely reduced. In addition, it is possible to avoid the deterioration of the film formed on the substrate due to heat and the adverse effects due to thermal stress. Moreover, since it is not necessary to heat the whole substrate, energy efficiency is high. Furthermore, unlike the COR, a two-chamber apparatus is unnecessary, and an increase in apparatus installation area can be avoided. Furthermore, since the temperature at the time of cleaning may be at most about 300 ° C., a heater with special performance is not required for heating the energy medium gas, and the cost of the apparatus is not increased.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view schematically showing an example of a processing apparatus used for carrying out the dry cleaning method according to the first embodiment of the present invention.

  The processing apparatus 100 includes a substantially cylindrical chamber 1 that is airtight. A circular opening 2 is formed at the center of the bottom wall 1 a of the chamber 1, and a mounting table 3 for horizontally supporting a wafer W as a semiconductor substrate in the chamber 1 is formed in the opening 2. Is provided. A heat insulating portion 4 is provided between the mounting table 3 and the bottom wall 1 a and is airtightly joined to the bottom wall 1 a of the chamber 1.

  An exhaust port 5 is formed in the side wall 1b of the chamber 1, and an exhaust device 7 including a high-speed vacuum pump is connected through an exhaust pipe 6 connected thereto. The exhaust pipe 6 is provided with a conductance variable valve 6a so that the exhaust amount from the chamber 1 can be adjusted. By operating the exhaust device 7, the gas in the chamber 1 is exhausted, and the inside of the chamber 1 can be decompressed at a high speed to a predetermined degree of vacuum via the exhaust pipe 6.

A shower head 10 is provided on the top wall 1 c of the chamber 1. A gas inlet 12 for introducing gas into the shower head 10 is provided on the upper wall of the shower head 10, and a pipe 13 for supplying an energy medium gas is connected to the gas inlet 12. The other end of the pipe 13 connected to the gas inlet 12 is connected to an energy medium gas supply source 23 for supplying energy medium gas. The pipe 13 is provided with a mass flow controller 21 and front and rear valves 22. As the energy medium gas, an inert gas such as He, Ar, Kr, Xe, or N ₂ can be suitably used.

  A diffusion chamber 14 is formed inside the shower head 10, and a plurality of discharge holes 11 for discharging the energy medium gas toward the mounting table 3 are formed in the lower part. Then, the gas introduced from the gas introduction port 12 is diffused in the space of the diffusion chamber 14 and discharged perpendicularly to the wafer W mounted on the mounting table 3 in the chamber 1 from the discharge hole 11.

  Around each discharge hole 11 of the shower head 10, a heater 15, which is a heating unit for heating the energy medium gas in the shower head 10, is provided. Around the heater 15, a heat insulating portion 16 made of a material having low thermal conductivity, for example, heat-resistant synthetic resin, quartz, ceramics, or the like is provided to be insulated. Then, the energy medium gas passing through the inside of the heater 15 is instantaneously and efficiently heated.

  A gas introduction port 17 is provided on the side of the side wall 1 b of the chamber 1 facing the exhaust port 5, and a pipe 18 for supplying cleaning gas and purge gas into the chamber 1 is connected thereto. The other end of the pipe 18 is branched into two, one of which is connected to the cleaning gas supply source 26 via the mass flow controller 24a and the front and rear valves 25a and 25a, and the other is connected to the mass flow controller 24b. The purge gas supply source 27 is connected to the front and rear valves 25b and 25b.

  The cleaning gas supply source 26 supplies a cleaning gas for cleaning the surface of the wafer W. In this case, for example, silicon constituting the wafer W, a metal film on the surface of the wafer W, a silicon film, a silicide film, a metal oxide film formed on the surface of the wafer W wiring, organic contaminants, and the like are to be cleaned. To be removed.

Various types of cleaning gas can be used depending on the type of object to be cleaned. For example, in order to remove the oxide film (copper oxide) on the Cu wiring formed on the wafer W, an organic compound such as an organic acid, NH ₃ (ammonia), or the like can be used. In order to remove (silicon), HF (hydrogen fluoride), NH ₃ (ammonia), or the like can be used. In the case of an oxide film on a silicide such as CoSiOx or NiSiOx, a mixture of an organic acid and HF Can be suitably used. In order to remove organic pollutants by cleaning, for example, an organic compound such as an organic acid can be used as in the case of removing copper oxide.

Examples of the organic compound used as the cleaning gas when removing copper oxide and organic pollutants include organic acids, alcohols, and aldehydes. Among these, an organic acid is preferable, and a carboxylic acid can be suitably used as the organic acid. As the carboxylic acid, formic acid (HCOOH), acetic acid (CH ₃ COOH), propionic acid (CH ₃ CH ₂ COOH), butyric acid (CH ₃ (CH ₂ ) ₂ COOH), valeric acid (CH ₃ (CH ₂ ) ₃ COOH) Among these, formic acid (HCOOH) is preferable.

On the other hand, the purge gas supply source 27 is configured to supply a purge gas. The purge gas is a gas for purging the raw material gas remaining in the gas phase, the by-product in the gas phase generated by the reaction, and the energy medium gas containing a large amount of thermal energy. For example, Ar gas, He gas, N inert gas or H ₂ gas or the like, such as ₂ gas can be cited. By introducing the purge gas, it is possible to exhaust the residual raw material gas in the pipe 18, remove reaction by-products by replacing the atmosphere in the chamber 1, cool the wafer W, and the like.

  On the mounting table 3, for example, three wafer support pins (not shown) are provided so as to protrude and retract with respect to the surface of the mounting table 3 in order to support and lift the wafer W.

  A temperature control medium chamber 30 is formed inside the mounting table 3. As a temperature control medium set in advance to a predetermined temperature from the introduction path 31 a, for example, Galden (product of water or fluorine-based inert liquid) Name) etc. are introduced, and the temperature of the mounting table 3 can be adjusted by discharging from the discharge path 31b.

  The side wall 1b of the chamber 1 is provided with a loading / unloading port for loading / unloading the wafer W to / from a transfer chamber (not shown) adjacent to the processing apparatus 100, and a gate valve for opening / closing the loading / unloading port. (Both are not shown).

  Each component of the processing apparatus 100 is connected to and controlled by a process controller 50 having a microprocessor (computer). The process controller 50 is connected to a user interface 51 including a keyboard for an operator to input commands for managing the processing apparatus 100, a display for visualizing and displaying the operating status of the processing apparatus 100, and the like. ing. Further, the process controller 50 causes a control program for realizing various processes executed by the processing device 100 under the control of the process controller 50 or causes each component of the processing device to execute processing according to processing conditions. The storage unit 52 storing the program, i.e., the recipe, is connected. The recipe is stored in a storage medium. The storage medium may be a fixed one such as a hard disk or a portable one such as a CDROM or DVD. Furthermore, you may make it transmit a recipe suitably from another apparatus via a dedicated line, for example. If necessary, an arbitrary recipe is called from the storage unit 52 according to an instruction from the user interface 51 and is executed by the process controller 50, so that the cleaning process in the processing apparatus 100 is performed under the control of the process controller 50. Is done.

  Next, a procedure for removing an oxide film formed on a predetermined film on the wafer W by dry cleaning using such a processing apparatus 100 will be described with reference to a flowchart of FIG.

  First, the gate valve (not shown) is opened, and the wafer W is loaded into the chamber 1 from the loading / unloading port and mounted on the mounting table 3 (step 1). Next, a temperature control medium having a predetermined temperature is introduced into the temperature control medium chamber 30, and the temperature is adjusted to a temperature at which the cleaning gas is easily adsorbed on the surface of the wafer W (step 2).

  Then, the chamber 1 is evacuated by the vacuum pump of the exhaust device 7, the valve 25 a is opened, and the cleaning gas supply source 26 controls the flow rate of the cleaning gas by the mass flow controller 24 a and the chamber 1 through the gas inlet 17. And is adsorbed on the surface of the wafer W (step 3). That is, by introducing the cleaning gas into the chamber 1 and exhausting the interior of the chamber 1 with the exhaust device 7, as shown by the white arrows in FIG. 1, the gas is introduced from the gas introduction port 17 toward the exhaust port 5. A flow of a cleaning gas is formed in a direction parallel to the surface of the wafer W placed on the mounting table 3, whereby the cleaning gas is physically or chemically adsorbed on the surface of the wafer W.

  Next, the valve 25a is closed and the valve 25b is opened, and the inside of the chamber 1 is exhausted while supplying the purge gas from the purge gas supply source 27 to the chamber 1 through the gas inlet 17 while controlling the flow rate by the mass flow controller 24b. Thus, the inside of the chamber 1 is purged, and the cleaning gas remaining in the gas phase state in the chamber 1 is removed (step 4).

  Next, before the energy medium gas is introduced into the chamber, the pressure inside the chamber 1 is once increased (step 5). This step is to prevent temperature drop due to expansion of the energy medium gas and to prevent desorption and diffusion of the cleaning gas adsorbed on the surface of the wafer W when the energy medium gas is introduced into the chamber next time. To be done.

  The pressure increase can be performed, for example, by adjusting the exhaust conductance with a conductance variable valve 6a interposed in the exhaust pipe 6 between the exhaust port 5 and the exhaust device 7 while continuously introducing the purge gas. At this time, the pressure in the chamber 1 is preferably a predetermined pressure within a range of 500 to 5000 Pa, for example.

  For the purpose of shortening the processing time, it is possible to simultaneously perform the steps 4 and 5, that is, to increase the pressure by adjusting the exhaust amount by the pressure adjusting means simultaneously with the start of the introduction of the purge gas into the chamber 1. It is.

  Next, the valve 25 b is closed, the valve 22 is opened, and the flow rate of the energy medium gas from the energy medium gas supply source 23 is controlled by the mass flow controller 21, and the diffusion chamber 14 of the shower head 10 through the pipe 13 and the gas inlet 12. The energy medium gas that has been introduced into the chamber and received thermal energy by the heater 15 is discharged into the chamber 1 to give thermal energy to the adsorbed cleaning gas (step 6). That is, the energy medium gas transports the thermal energy given by the heater 15 to the cleaning gas adsorbed on the surface of the wafer W (substrate), thereby causing a cleaning reaction.

  At this time, the energy medium gas introduced into the diffusion chamber 14 passes through a large number of ejection holes 11 provided in the lower portion of the shower head 10 and reaches the surface of the wafer W arranged oppositely as indicated by black arrows in FIG. It is injected almost vertically. At this time, the energy medium gas is heated to a predetermined high temperature by the heater 15 and collides with the surface of the wafer W with sufficient thermal energy.

  The heating temperature of the energy medium gas is preferably set to a desired temperature of 80 ° C. or higher and 300 ° C. or lower depending on the cleaning reaction. More preferably, it is 200 degrees C or less. At this time, the pressure in the chamber 1 is preferably maintained at the increased pressure in the step 5 from the viewpoint of efficiently performing the cleaning reaction.

  As described above, the cleaning gas is adsorbed on the surface of the wafer W, and thermal energy necessary for the cleaning reaction is efficiently supplied by spraying a high-temperature energy medium gas thereon. As a result, a cleaning reaction proceeds on the surface of the wafer W, and an object to be cleaned such as an oxide film or an organic contaminant formed on the surface of the wafer W is removed.

For example, when the copper oxide film on the Cu wiring formed on the wafer W is removed by cleaning with formic acid, the formic acid is covered so as to cover the copper oxide film (Cu ₂ O) 201 as shown in FIG. When thermal energy is applied by an energy medium gas with (HCOOH) 202 adsorbed as shown in FIG. 3B, the copper oxide film 201 is removed by the reaction shown in the following formula (1). Is done.
Cu ₂ O + 2HCOOH → 2Cu (HCOO) ↑ + H ₂ O ↑ (1)

Further, when the silicon oxide formed on the silicon portion of the wafer W is removed by cleaning with hydrogen fluoride (HF), the silicon oxide film is removed by the reaction shown in the following formula (2).
SiO ₂ + 4HF → SiF ₄ ↑ + 2H ₂ O ↑ (2)

  The energy medium gas may be heated to a predetermined temperature by an external heating means before being introduced into the shower head 10. In this case, the heater 15 provided at the lower part of the shower head 10 It can function as auxiliary heating means for final adjustment of the temperature of the energy medium gas.

  When the cleaning in step 6 is completed, the valve 22 is closed and the introduction of the energy medium gas is stopped. If the oxide film or the like on the surface of the wafer W has been removed at this point, the cleaning is completed. However, since it is difficult to remove the oxide and the like by one operation, the cleaning gas is adsorbed as described later. It is preferable to repeat a series of steps including a step of causing a cleaning reaction with an energy medium gas a plurality of times.

  In such a case, it is preferable to lower the pressure in the chamber 1 after stopping the supply of the energy medium gas (step 7). By reducing the pressure in the chamber 1 after the cleaning reaction, the energy medium gas can be exhausted to quickly stop the energy supply to the surface of the wafer W, and the heat on the surface of the wafer W can be quickly removed. . As a result, preparation for the next cleaning gas adsorption can be quickly performed. In addition, by reducing the pressure in this way, it is expected that the action of promoting the separation of the reaction byproduct from the surface of the wafer W and the action of promoting the discharge of the gas phase byproduct after the reaction and shortening the gas purge process. be able to.

  The decompression at this time can be performed by fully opening the conductance variable valve 6 a and exhausting the chamber 1 by the exhaust device 7 under the control of the process controller 50. At this time, it is preferable to reduce only the pressure increased in step 5. As a result, the pressure can be adjusted at the time of supplying the cleaning gas in the next cycle.

  Next, the valve 25b is opened and the inside of the chamber 1 is exhausted by the exhaust device 7 while supplying the purge gas from the purge gas supply source 27 to the chamber 1 through the gas inlet 17 while controlling the flow rate by the mass flow controller 24b. The inside of the chamber 1 is purged (step 8). As a result, the thermal energy transported by the energy medium gas is removed, and by-products adsorbed on the surface of the wafer W and in the gas phase generated by the reaction are removed to prepare for the adsorption of the cleaning gas in the next cycle.

As described above, the process of adsorbing the cleaning gas on the surface of the wafer W, the process of purging the chamber 1 with the purge gas, the process of supplying the thermal energy to the cleaning gas on the surface of the wafer W with the energy medium gas and causing the cleaning reaction By (Steps 2 to 8), the oxide film or the like on the surface of the wafer W is removed by the amount of reaction generated by the cleaning gas adsorbed first. Then, by repeating these steps 2 to 8 a predetermined number of times according to the thickness of the formed oxide film or the like, the oxide film or the like on the surface of the wafer W can be completely removed.
The pressure increase in step 5 and the pressure reduction in step 7 are optional steps, and the purge in step 4, the reaction in step 6, and the purge in step 8 can be performed while the chamber 1 is maintained at a constant pressure. It is.

  After the oxide film on the surface of the wafer W is removed as described above, the gate valve (not shown) is opened and the wafer W is unloaded from the loading / unloading port (step 9). As described above, the cleaning process for one wafer W is completed.

  When cleaning is performed in this way, since the heat energy for the cleaning reaction is given by the energy medium gas supplied from above the wafer W, only the surface of the wafer W that needs to be cleaned is heated, Thermal effects can be extremely reduced, and adverse effects due to heat deterioration and thermal stress of the film formed on the wafer W can be avoided. For this reason, it is effective for a wafer having a Cu / Low-k film structure, which is particularly concerned about thermal effects. In addition, energy efficiency is high because it is not necessary to heat the entire wafer.

  Further, since the temperature at the time of cleaning may be at most about 300 ° C., the heater 15 for heating the energy medium gas is not required to have a special performance and may be low in cost, and the apparatus cost may be low. it can. Furthermore, unlike the COR, a two-chamber apparatus is unnecessary, and an increase in apparatus installation area can be avoided.

Next, a second embodiment of the present invention will be described.
FIG. 4 is a cross-sectional view schematically showing an example of a processing apparatus used for carrying out the dry cleaning method according to the second embodiment of the present invention.

  In this processing apparatus 101, unlike the film forming apparatus 100 of the first embodiment, a method of supplying a heated cleaning gas via a shower head is performed.

  Specifically, a shower head 60 is provided on the top wall 1 c of the chamber 1. The shower head 60 includes an upper block body 61, a middle block body 62, and a lower block body 63. In the lower block body 63, discharge holes 64 and 65 for discharging gas are alternately formed. A first gas inlet 66 and a second gas inlet 67 are formed on the upper surface of the upper block body 61.

The first gas introduction port 66 is connected to the dilution gas supply source 83 and the cleaning gas supply source 86 via a gas line 72 that is branched in two along the way, and the second gas introduction port 67 is connected to the gas line 73. To a purge gas supply source 89. The branch line on the side of the dilution gas supply source 83 of the gas line 72 is provided with a mass flow controller 81 and its front and rear valves 82. The branch line on the side of the cleaning gas supply source 86 is provided with the mass flow controller 84 and its front and rear. A valve 85 is provided. The gas line 73 is provided with a mass flow controller 87 and front and rear valves 88. The dilution gas is for diluting the cleaning gas, and an inert gas such as He, Ar, Kr, Xe, or N ₂ can be suitably used.

  In the upper block body 61, a large number of gas passages 68 are branched from the first gas inlet 66. Gas passages 69 are formed in the middle block body 62, and the gas passages 68 communicate with these gas passages 69. Further, the gas passage 69 communicates with the plurality of discharge holes 64 of the lower block body 63. In the upper block body 61, a large number of gas passages 70 are branched from the second gas introduction port 67. A gas passage 71 is formed in the middle block body 62, and the gas passage 70 communicates with the gas passage 71. Further, the gas passage 71 communicates with the discharge hole 65 of the lower block body 63.

  Around each discharge hole 64, a heater 74 which is a heating means for heating the processing gas and the dilution gas in the shower head 60 is provided. Furthermore, a heat insulating portion 75 made of, for example, heat resistant synthetic resin, quartz, ceramics, or the like is provided around the heater 74 as a material having low thermal conductivity, and is insulated.

Then, the cleaning gas from the cleaning gas supply source 86 is diluted with the dilution gas from the dilution gas supply source 83 as necessary, reaches the shower head 60 through the gas line 72, is heated by the heater 74, and is discharged to the discharge hole 64. The cleaning gas discharged and heated from the wafer is directly supplied to the surface of the wafer W. Thus, in this embodiment, since it is not necessary to adsorb the cleaning gas to the wafer W, for example, H ₂ gas or CO can be used as a gas for removing the copper oxide film in addition to the above gas.

  Exhaust ports 76 are formed at two locations on the bottom wall 1 a of the chamber 1, and an exhaust device 7 including a high-speed vacuum pump is connected through exhaust pipes 77 connected thereto. Then, by operating the exhaust device 7, the gas in the chamber 1 is exhausted, and the inside of the chamber 1 can be decompressed at a high speed to a predetermined degree of vacuum via the exhaust pipe 77. In addition, the conductance variable valve 78 provided between the exhaust port 76 of the pipe 77 and the exhaust device 7 adjusts the exhaust conductance and the pressure in the chamber 1 under the control of the process controller 50. The voltage can be increased or decreased.

  Since other configurations are the same as those of the apparatus of FIG. 1, the same components as those of FIG.

  As shown in the flowchart of FIG. 5, the processing apparatus 101 configured in this manner first opens a gate valve (not shown) and loads the wafer W into the chamber 1 from the loading / unloading port, and loads the wafer W on the mounting table 3. (Step 11). Next, a temperature control medium having a predetermined temperature is introduced into the temperature control medium chamber 30, and the temperature of the wafer W is adjusted to a predetermined temperature (step 12).

  Then, while the chamber 1 is evacuated by the vacuum pump of the exhaust device 7, the valve 85 is opened, and the flow rate of the cleaning gas from the cleaning gas supply source 86 is controlled by the mass flow controller 84 while the gas line 72 and the gas inlet 66 are set. And is discharged into the chamber 1 while being heated by the heater 64 while passing through the discharge hole 64 (step 13). At this time, the cleaning gas may be diluted by supplying a dilution gas from the dilution gas supply source 83 as necessary. When the heated cleaning gas reaches the surface of the wafer W, a cleaning reaction occurs with a cleaning target such as an oxide film or an organic contaminant formed on the surface of the wafer W, and the cleaning target is removed.

For example, when the copper oxide film on the Cu wiring formed on the wafer W is removed by cleaning with formic acid, formic acid (HCOOH) heated against the copper oxide film (Cu ₂ O) 211 as shown in FIG. ) 212 is directly supplied, the reaction shown in the above formula (1) occurs, and the copper oxide film 211 is removed.

In this embodiment, as described above, H ₂ gas or CO gas can also be used when removing the copper oxide film. When H ₂ gas is used, the following equation (3) is obtained. When a CO gas is used by the reaction, the copper oxide film can be removed by the reaction shown in the following formula (4).
Cu ₂ O + H ₂ → 2Cu + H ₂ O (3)
Cu ₂ O + CO → 2Cu + CO ₂ (4)

  When the cleaning in step 13 is completed, the valve 85 is closed to stop the introduction of the cleaning gas, the valve 88 is opened, the purge gas is supplied from the purge gas supply source 89 and the chamber 1 is exhausted by the exhaust device 7. 1 is purged (step 14). Thereby, the cleaning gas is removed from the chamber 1 and the shower head 60, and the temperature in the wafer chamber 1 is lowered.

  Thereafter, the gate valve (not shown) is opened and the wafer W is unloaded from the loading / unloading port (step 15). As described above, the cleaning process for one wafer W is completed.

  In this embodiment, since the heated cleaning gas is supplied to the surface of the wafer W, as in the previous embodiment, only the surface of the wafer W that basically needs to be cleaned is heated and the thermal effect on the wafer W is affected. Therefore, the deterioration of the film formed on the wafer W due to heat and the adverse effect due to thermal stress can be avoided. For this reason, it is effective for a wafer having a Cu / Low-k film structure, which is particularly concerned about thermal effects. In addition, energy efficiency is high because it is not necessary to heat the entire wafer. Furthermore, since only the cleaning gas is supplied, cleaning can be performed very easily.

  Further, by adjusting the supply time of the cleaning gas, it is possible to remove the object to be cleaned by supplying the cleaning gas once. However, if the heated cleaning gas is supplied to the wafer W for a long time, the temperature of the entire wafer W may increase. In such a case, it is possible to suppress an increase in the temperature of the wafer W by alternately repeating the supply of the heated cleaning gas and the supply of the purge gas a plurality of times.

  Furthermore, in this embodiment, since the temperature at the time of cleaning may be at most about 300 ° C., the apparatus cost can be reduced, and further, since the process is performed in one chamber, the apparatus installation area is increased. It can be avoided.

In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible.
For example, in the first embodiment, a heater for heating the energy medium gas is provided around the discharge hole of the shower head, and in the second embodiment, a heater for heating the cleaning gas is provided around the discharge hole of the shower head. However, the present invention is not limited to this, and a heater may be provided in another part such as the inside of the diffusion chamber 14.

  Moreover, although the fixed type was used as a mounting table in the said embodiment, what was equipped with the mechanism which can be rotated on a horizontal surface can also be used. Thereby, cleaning reaction can be advanced more uniformly.

  Furthermore, in the above-described embodiment, an example in which the oxide film and organic impurities formed on the semiconductor wafer are removed by cleaning has been described. However, the present invention is not limited to this, and any cleaning target that can be removed by reaction with a cleaning gas is applicable.

  The present invention can be suitably used for removing, for example, oxide films and organic impurities formed on the surface of a semiconductor wafer during the manufacturing process of various semiconductor devices.

Sectional drawing which shows typically an example of the processing apparatus used in order to implement the dry cleaning method which concerns on the 1st Embodiment of this invention. 3 is a flowchart illustrating a dry cleaning method according to the first embodiment of the present invention. FIG. 3 is a schematic diagram showing a specific example of the dry cleaning method according to the first embodiment of the present invention. Sectional drawing which shows typically an example of the processing apparatus used in order to implement the dry cleaning method which concerns on the 2nd Embodiment of this invention. 9 is a flowchart for explaining a dry cleaning method according to a second embodiment of the present invention. FIG. 6 is a schematic diagram showing a specific example of a dry cleaning method according to a second embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Chamber 2; Opening part 3; Mounting stand 4; Heat insulation part 7; Exhaust device 10,60; Shower head 15,74; Heater 17,66,67; Gas inlet 23; Energy medium gas supply source 26,86; Cleaning gas supply source 27, 89; purge gas supply source 30; temperature control medium chamber 50; process controller 83; dilution gas supply source 100; processing apparatus W;

Claims (17)

A dry cleaning method for mounting a substrate on a mounting table provided in a processing chamber capable of evacuation under reduced pressure, and dry cleaning the substrate surface,
Introducing a cleaning gas into the processing chamber and adsorbing the cleaning gas on the substrate;
After the adsorption of the cleaning gas onto the substrate, the processing chamber, introducing energy medium gas heat energy is applied, thermal energy is supplied to the cleaning gas adsorbed on the substrate from the energy medium gas And a step of advancing a cleaning reaction on the substrate surface.   2. The dry cleaning method according to claim 1, further comprising a step of purging the processing chamber by introducing a purge gas between the cleaning gas and the energy medium gas.   The step of adsorbing the cleaning gas onto the substrate, the step of introducing the energy medium gas into the processing chamber and advancing a cleaning reaction, and the step of purging the processing chamber by introducing a purge gas into the processing chamber are sandwiched. The dry cleaning method according to claim 1, wherein the dry cleaning method is performed alternately.   The dry cleaning method according to any one of claims 1 to 3, wherein the energy medium gas is given thermal energy immediately before being supplied to the substrate in the processing chamber.   5. The cleaning gas according to claim 1, wherein the cleaning gas is supplied so that a gas flow parallel to the substrate placed on the mounting table is formed. Dry cleaning method.   The said energy medium gas is supplied so that a perpendicular | vertical gas flow may be formed with respect to the board | substrate mounted in the said mounting base. Dry cleaning method.   The dry cleaning method according to claim 1, wherein the energy medium gas is an inert gas. The dry cleaning method according to any one of claims 1 to 7 , wherein the cleaning gas reacts with an oxide film or an organic pollutant on the substrate to remove them. The dry cleaning method according to any one of claims 1 to 8 , wherein the cleaning reaction is performed at a temperature of 80 to 300 ° C. The dry cleaning method according to any one of claims 1 to 9, wherein the pressure in the processing chamber is increased before the energy medium gas is introduced into the processing chamber. A processing chamber that accommodates a substrate and performs a cleaning process, and can be evacuated under reduced pressure ;
A mounting table for mounting a substrate in the processing chamber;
A cleaning gas introduction mechanism for introducing a cleaning gas into the processing chamber;
An energy medium introduction mechanism for introducing an energy medium gas to which thermal energy is given into the processing chamber;
An exhaust mechanism for exhausting the processing chamber;
After the adsorption of the cleaning gases to the substrate surface by introducing the cleaning gas into the processing chamber, introducing the energy medium gas into the processing chamber, said cleaning gas adsorbed on the substrate from the energy medium gas A substrate processing apparatus comprising: a control mechanism that supplies thermal energy to control a cleaning reaction to proceed on the substrate surface. The cleaning gas introduction mechanism and the pumping mechanism, to claim 11, characterized by introducing the cleaning gas as parallel gas flow is formed against the substrate placed in a mounting table exhaust The substrate processing apparatus as described. Claim 11, wherein the energy transfer medium intake mechanism and the pumping mechanism, to introduce the energy medium gas so that vertical gas flow is formed for substrate placed in a mounting table exhaust Or the substrate processing apparatus of Claim 12 . The substrate processing apparatus according to claim 13 , wherein the energy medium introduction mechanism includes a shower head that discharges the energy medium gas into a processing container. The substrate processing apparatus according to claim 14 , wherein the energy medium introduction mechanism includes a heater that applies thermal energy to the energy medium gas provided in the shower head. The substrate processing apparatus according to claim 11, wherein the pressure in the processing chamber is increased before the energy medium gas is introduced into the processing chamber. A storage medium that operates on a computer and stores a program for controlling a processing apparatus, the program being stored in the computer so that the dry cleaning method according to any one of claims 1 to 10 is performed at the time of execution. A storage medium for controlling a processing device.

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