Patent ID: 12215417

DETAILED DESCRIPTION

Embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings.

<Substrate Processing Device>

FIG.1is a sectional view illustrating an example of a substrate processing device according to an embodiment of the present disclosure. In this example, a COR processing apparatus which performs a chemical oxide removal (COR) process (etching process) will be described as the substrate processing device.

A typical example of the COR process is a substrate process of supplying a gas including an HF gas and a gas including an NH3gas onto an oxide film existing on a surface of a substrate such as a silicon wafer inside a chamber, thus removing the oxide film from the surface of the silicon wafer.

As illustrated inFIG.1, a COR processing apparatus100includes a hermetically sealed chamber10. The chamber10is made of, for example, aluminum or an aluminum alloy, and includes a chamber main body51and a lid52. The chamber main body51includes a lateral wall portion51aand a bottom portion51b. An upper portion of the chamber main body51is opened and closed by the lid52. The lateral wall portion51aand the lid52are sealed by a seal member51cto secure the airtightness of the chamber10.

Two processing parts11aand11bfor performing a substrate process on a plurality of target substrates are installed inside the chamber10. The two processing parts11aand11binclude substrate mounting tables61aand61b, respectively. Wafers Wa and Wb as target substrates are mounted on the respective substrate mounting tables61aand61bin a horizontal posture. Gas introduction members12aand12bfor introducing a processing gas into the chamber10are installed above the substrate mounting tables61aand61b, respectively. The gas introduction members12aand12bare installed inward of the lid52. The gas introduction member12aand the substrate placing table61aface each other, and the gas introduction member12band the substrate placing table61bface each other. A cylindrical inner wall71ais installed so as to surround the gas introduction member12aand the substrate mounting table61a, and a cylindrical inner wall71bis installed so as to surround the gas introduction member12band the substrate mounting table61b. The inner walls71aand71bare installed to extend from the inner side of an upper wall of the lid52to the bottom portion51bof the chamber main body51. Upper portions of the inner walls71aand71bconstitute lateral walls of the gas introduction members12aand12b, respectively. A space between the gas introduction member12aand the substrate mounting table61aand a space between the gas introduction member12band the substrate mounting table61bare substantially sealed by the inner walls71aand71b, respectively. These spaces constitute process spaces S in which the wafers Wa and Wb are subjected to the substrate process, respectively.

A gas supply mechanism14for supplying a gas to each of the gas introduction members12aand12b, an exhaust mechanism15for exhausting the interior of the chamber10, and a control part16for controlling the COR processing apparatus100are installed outside the chamber10. A loading/unloading port (not shown) through which the wafer W is loaded into and unloaded is formed in the lateral wall portion51aof the chamber main body51. The loading/unloading port can be opened and closed by a gate valve (not shown). A loading/unloading port (not shown) is also formed in each of the inner walls71aand72band can be opened and closed by a shutter (not shown).

Each of the processing parts1aand11bhas substantially a circular shape. Each of the substrate mounting tables61aand61bis supported by a base block62. The base block62is fixed to the bottom portion51bof the chamber main body51. A temperature regulator63for regulating a temperature of the wafer W is installed inside each of the substrate mounting tables61aand61b. The temperature regulator63is provided with a pipeline through which, for example, a temperature regulating medium (for example, water) circulates. By heat exchange with the temperature regulating medium flowing in the pipeline, the temperature of the wafer W is controlled. In addition, a plurality of lifting pins (not shown) used to transfer the wafer W are installed in the substrate mounting tables61aand61bso as to be moved upward and downward on a wafer mounting surface.

The gas supply mechanism14supplies a processing gas, such as an HF gas or an NH3gas, and an inert gas (dilution gas), such as an Ar gas or a N2gas, to the processing parts11aand11bvia the gas introduction members12aand12b, respectively. The gas supply mechanism14includes gas supply sources, supply pipes, valves, flow rate controllers represented by mass flow controllers and so on, which correspond to the respective gases.

FIG.2is a system configuration view illustrating an example of a system configuration of the gas supply mechanism14. As illustrated inFIG.2, the gas supply mechanism14includes an Ar gas supply source141, an HF gas supply source142, an N2gas supply source143and an NH3gas supply source144as the gas supply sources.

In this example, the HF gas supplied from the HF gas supply source142is diluted with an Ar gas supplied from the Ar gas supply source141and then supplied to the gas introduction members12aand12b. Likewise, the NH3gas supplied from the NH3gas supply source144is also diluted with the N2gas supplied from the N2gas supply source143and then supplied to the gas introduction members12aand12b.

An HF gas supply pipe145through which the HF gas flows is branched into two HF gas supply pipes145aand145bwhich are respectively connected to a supply pipe146aconnected to the gas introduction member12aand a supply pipe146bconnected to the gas introduction member12b. An Ar gas supply pipe147through which the Ar gas flows is branched into two Ar gas supply pipes147aand147bwhich are respectively connected to the HF gas supply pipes145aand145b. Thus, the HF gas can be diluted with the Ar gas.

Similarly, an NH3gas supply pipe148through which the NH3gas flows is branched into two NH3gas supply pipes148aand148bwhich are respectively connected to the supply pipes146aand146b. A N2gas supply pipe149through which the N2gas flows is branched into two N2gas supply pipes149aand149bwhich are respectively connected to the NH3gas supply pipes148aand148b. Thus, the NH3gas can be diluted with the N2gas.

In addition to being used as dilution gases, the Ar gas and the N2gas are also used as a purge gas or as a supplement gas for pressure regulation to be described later.

Mass flow controllers (MFCs)150ato150hand opening/closing valves151ato151hfor opening/closing the respective supply pipes are respectively installed in the HF gas supply pipes145aand145b, the Ar gas supply pipes147aand147b, the NH3gas supply pipes148aand148b, and the N2gas supply pipes149aand149b. The MFCs150ato150hand the opening/closing valves151ato151hcan be controlled by the control part16independently of each other.

For example, in the case of performing the normal COR process in the two processing parts11aand11b, both the HF gas and the NH3gas are supplied to each of the gas introduction members12aand12b. In this case, the control part16controls all the opening/closing valves to be opened, as shown in the following “Case a”.

[Case a]

Supply System to Gas Introduction Member12a

Opening/closing valve 151a (Ar)OpenedOpening/closing valve 151c (HF)OpenedOpening/closing valve 151e (N2)OpenedOpening/closing valve 151g (NH3)Opened
Supply System to Gas Introduction Member12b

Opening/closing valve 151b (Ar)OpenedOpening/closing valve 151d (HF)OpenedOpening/closing valve 151f (N2)OpenedOpening/closing valve 151h (NH3)Opened

On the other hand, the opening/closing valves may be controlled such that conditions of gases to be supplied to the processing parts11aand11bvia the gas introduction members12aand12bare different from each other. For example, the opening/closing valves may be controlled as shown in the following “Case b” and “Case c”.

[Case b]

Supply System to Gas Introduction Member12a

Opening/closing valve 151a (Ar)OpenedOpening/closing valve 151c (HF)OpenedOpening/closing valve 151e (N2)OpenedOpening/closing valve 151g (NH3)Opened
Supply System to Gas Introduction Member12b

Opening/closing valve 151b (Ar)OpenedOpening/closing valve 151d (HF)ClosedOpening/closing valve 151f (N2)OpenedOpening/closing valve 151h (NH3)Closed
[Case c]
Supply System to Gas Introduction Member12a

Opening/closing valve 151a (Ar)OpenedOpening/closing valve 151c (HF)ClosedOpening/closing valve 151e (N2)OpenedOpening/closing valve 151g (NH3)Closed
Supply System to Gas Introduction Member12b

Opening/closing valve 151b (Ar)OpenedOpening/closing valve 151d (HF)OpenedOpening/closing valve 151f (N2)OpenedOpening/closing valve 151h (NH3)Opened

That is to say, in Case b, from the state of Case a, the opening/closing valve151dand the opening/closing valve151hare closed to stop the supply of the HF gas and the NH3gas as processing gases and supply only the Ar gas and the Na gas to the gas introduction member12b, and the HF gas and the NH3gas as the processing gases continue to be supplied to the gas introduction member12a. Conversely, in Case c, the supply of the HF gas and the NH3gas to the gas introduction member12ais stopped, and the HF gas and the NH3gas as the processing gases continue to be supplied to the gas introduction member12b.

For this reason, in Case b, the HF gas and the NH3gas are supplied from the gas introduction member12ato the processing part11a, together with the Ar gas and the Na gas which are inert gases, respectively, while only the Ar gas and the Na gas which are inert gases are supplied from the gas introduction member12bto the processing part11b. Conversely, in Case c, the HF gas and the NH3gas are supplied from the gas introduction member12bto the processing part11b, together with the Ar gas and the Na gas which are inert gases, respectively, while only the Ar gas and the Na gas which are inert gases are supplied from the gas introduction member12ato the processing part11a. In this manner, during processing, it is possible to simultaneously supply the gases to the processing part11aand the processing part11bunder different gas supply conditions. Substrate processing modes by the control of the valves will be described in detail later.

The gas introduction members12aand12bare provided to introduce the gases from the gas supply mechanism14into the chamber10and supply the gases to the processing parts11aand11b. Each of the gas introduction members12aand12bhas a gas diffusion space64defined therein and has a cylindrical shape. Gas introduction holes65penetrating the upper wall of the chamber10are respectively formed in the upper surfaces of the gas introduction members12aand12b. A large number of gas discharge holes66connected to each of the gas diffusion spaces64are respectively formed in the bottom surfaces of the gas introduction members12aand12b. Gases such as the HF gas and the NH3gas supplied from the gas supply mechanism14reach the gas diffusion spaces64via the gas introduction holes65, diffuse inside the gas diffusion spaces64, and are uniformly discharged from the gas discharge holes66in the form of a shower. That is to say, each of the gas introduction members12aand12bfunctions as a gas dispersion head (shower head) that dispersedly discharges a gas. The gas introduction members12aand12bmay be of a post-mix type in which the HF gas and the NH3gas are discharged into the chamber10through different flow paths.

The exhaust mechanism15includes an exhaust pipe101connected to an exhaust port (not shown) formed in the bottom portion51bof the chamber10. Further, the exhaust mechanism15includes an automatic pressure control valve (APC)102for controlling an internal pressure of the chamber10and a vacuum pump103for exhausting the interior of the chamber10, which are installed in the exhaust pipe101. The exhaust port is formed outside the inner walls71aand71b. A number of slits are formed in portions of the inner walls71aand71bbelow the substrate mounting tables61aand61b, respectively, so that the exhaust mechanism15can exhaust the interior of the chamber10from both the processing parts11aand11b. Thus, the interiors of the processing parts11aand11bare exhausted by the exhaust mechanism15at the same time. The APC102and the vacuum pump103are shared by both the processing parts11aand11b.

In addition, in order to measure the internal pressure of the chamber10, a high-pressure capacitance manometer105aand a low-pressure capacitance manometer105b, which are pressure gauges, are installed so as to be inserted into the exhaust spaces68from the bottom portion51bof the chamber10, respectively. The opening degree of the automatic pressure control valve (APC)102is controlled based on a pressure detected by the capacitance manometer105aor105b.

The control part16includes a process controller161provided with a microprocessor (computer) for controlling various components of the COR processing apparatus100. A user interface162is connected to the process controller161. The user interface162includes a keyboard or a touch panel display for allowing an operator to input commands to manage the COR processing apparatus100, a display for visualizing and displaying the operation status of the COR processing apparatus100, and the like. In addition, a storage part163is connected to the process controller161. The storage part163stores a control program for realizing various processes executed in the COR processing apparatus100under the control of the process controller161, processing recipes which are control programs for causing the various components of the COR processing apparatus100to execute their respective prescribed processes according to processing conditions, various databases and the like. The processing recipes are stored in an appropriate storage medium (not shown) in the storage part163. Then, as necessary, any of the processing recipes is called from the storage part163and is executed by the process controller161, so that a desired process is performed in the COR processing apparatus100under the control of the process controller161.

Further, in the present embodiment, the control part16has a significant feature in that the MFCs150ato150hand the opening/closing valves151ato151hof the gas supply mechanism14are independently controlled as described above.

<Substrate Processing Operation>

Next, a substrate processing operation performed by such a substrate processing device will be described.FIGS.3A and3Bare sectional views for explaining a substrate processing operation performed by the COR processing apparatus100according to an embodiment.

Two wafers Wa and Wb on each of which an etching target film (for example, SiO2film) has been formed are respectively loaded into the processing parts11aand11binside the chamber10, and are respectively mounted on the substrate mounting tables61aand61b. Then, a pressure stabilizing step of stabilizing the internal pressure of the chamber10by adjusting the internal pressure to a predetermined pressure by means of the exhaust mechanism15is performed, and subsequently, a substrate process step is performed. Since the processing parts11aand11bshare the exhaust mechanism15, the pressure adjustment during the pressure stabilizing step and the substrate process step is performed by the common automatic pressure control valve (APC)102.

The substrate process step is performed with a common substrate processing mode illustrated inFIG.3Aand an independent substrate processing mode illustrated inFIG.3B.

(Common Substrate Processing Mode)

The common substrate processing mode is a mode in which the wafers Wa and Wb are processed under the same gas conditions. With this common substrate processing mode, a COR process is performed in both the processing parts11aand11b. In this mode, the state of the opening/closing valves151ato151hcorresponds to “Case a” described above. Thus, as illustrated inFIG.3A, the HF gas and the NH3gas respectively diluted with the Ar gas and the N2gas as inert gases are supplied from the gas introduction members12aand12bonto the wafers Wa and Wb, whereby the same substrate process is performed on both the wafers Wa and Wb.

(Independent Substrate Processing Mode)

The independent substrate processing mode is a mode in which the wafers Wa and Wb are processed under different gas conditions. In this mode, the state of the opening/closing valves151ato151hcorresponds to, for example, “Case b” described above. Thus, as illustrated inFIG.3B, the HF gas and the NH3gas respectively diluted with the Ar gas and the N2gas are supplied from the gas introduction member12aonto the wafer Wa of the processing part11a, and only the Ar gas and the N2gas are supplied from the gas introduction member12bonto the wafer Wb of the processing part11b, whereby different substrate processes are performed on the wafers Wa and Wb. That is to say, the processing of the wafer Wa by the HF gas and the NH3gas is continued in the processing part11a, whereas the supply of the HF gas and the NH3gas onto the wafer Wb is stopped in the processing part11b. At this time, only the HF gas may be stopped and the NH3gas may be supplied to the processing part11b. An inert gas supplied from the gas introduction member12bmay be one of the Ar gas and the N2gas.

In the independent substrate processing mode, contrary toFIG.3B, the processing of the wafer Wb by the HF gas and the NH3gas may be performed in the processing part11b, whereas the supply of the HF gas and the NH3gas onto the wafer Wa may be stopped in the processing part11a. In this case, the state of the opening/closing valves151ato151hcorresponds to, for example, “Case c” described above. At this time, the supply of the HF gas to the processing part11amay be stopped, and the NH3gas may be supplied to the processing part11a. An inert gas supplied from the gas introduction member12amay be one of the Ar gas and the N2gas.

When it is desired to make a timing of the COR processing different between the processing part11aand the processing part11b, the independent substrate processing mode is a mode in which processing is performed in one processing part and no processing is performed in the other processing part.

When the independent substrate processing mode is applied in such a manner that the COR process is performed in the processing part11band no COR process is performed in the processing part11b, it may be considered to stop the supply of a gas from the gas introduction member12bto the processing part11b, as a reference example illustrated inFIG.4. However, since the exhaust mechanism15is shared by both the processing parts11aand11band the pressure is controlled by the single APC, if the supply of a gas from the gas introduction member12bis stopped while continuing to supply the HF gas and the NH3gas from the gas introduction member12a, a pressure difference occurs between the processing part11aand the processing part11b. Therefore, even when the process spaces S of the processing parts11aand11bare substantially sealed, the gas from the gas introduction member12aflows backward through slits formed in the lower portions of the inner walls71aand71band flows into the processing portion11b. This makes it difficult to completely stop the processing of the wafer Wb by the HF gas and the NH3gas in the processing part11b. For this reason, in the independent substrate processing mode, the Ar gas and the N2gas are supplied from the gas introduction member12b, as illustrated inFIG.3B. However, if the flow rates of the Ar gas and the N2gas are equal to those in the processing part11a, the total flow rate decreases, which also generates a pressure difference to cause a backward flow. This makes it difficult to stop the processing completely. Therefore, in the present embodiment, in the case where the processing is performed in the independent substrate processing mode, the gas supply mechanism14controls the flow rates of the Ar gas and the N2gas from the gas introduction member12bso as to prevent a pressure difference from occurring between the processing part11aand the processing part11b.

For example, the control part16can control the gas supply mechanism so that the pressure of the processing part11aand the pressure of the processing part11bbecome equal to each other so as to prevent the pressure difference from occurring between the processing part11aand the processing part11bby closing the opening/closing valves151dand151hto stop the supply of the HF gas and the NH3gas to the gas introduction member12band increasing the flow rates of the Ar gas and the N2gas by means of the MFCs150band150fwith the opening/closing valves151band151fopened. That is to say, the Ar gas and the N2gas are used as supplement gases for pressure regulation. As described above, in the independent substrate processing mode, the NH3gas may be supplied to the processing part11bwhich performs no processing, but in that case, only the Ar gas may be used as the supplement gas.

In this manner, for one of the processing parts11aand11b, which is intended to stop the substrate process, the pressure regulation is performed by supplying an inert gas as a supplement gas for pressure regulation rather than simply stopping the supply of a processing gas. Thus, even when the exhaust of gases from both the processing parts11aand11bby the single exhaust mechanism15is performed at the same time, it is possible to prevent the inflow of gas between the processing parts11aand11b.

(One Example of Process Sequence)

In this example, as illustrated in a flow chart ofFIG.5, after a pressure stabilizing step S1for stabilizing a pressure, a substrate process step (COR process) S2is performed in combination of the processing in the common substrate processing mode and the processing in the independent substrate processing mode, and then an exhausting step S3for exhausting a process space is performed. In performing the substrate process step S2, the independent substrate processing mode-based process S2-1is initially performed and subsequently the common substrate processing mode-based process S2-2is performed.

In the substrate process step S2, when the common substrate processing mode-based process S2-2is initially performed and the independent substrate processing mode-based process S2-1is then performed, even if a processing gas to be supplied to a processing part in which the processing is paused is switched to a supplement gas, etching (COR process) may proceed due to a reaction product and a residual gas on the wafer when the processing is paused under high pressure conditions.

Therefore, in this example, when performing the substrate process step S2followed by the pressure stabilizing step S1, the independent substrate processing mode-based process S2-1is first performed and subsequently the common substrate processing mode-based process S2-2is performed. Thus, it is possible to eliminate the influence of a reaction product and a residual gas, thereby improving the control accuracy of the etching amount.

In the transition from the independent substrate processing mode-based process S2-1to the common substrate processing mode-based process S2-2, as described above, in the processing part11b, the HF gas and the NH3gas as processing gases are introduced while the Ar gas and the N2gas are being supplied, or the HF gas is introduced while the Ar gas, the N2gas and the NH3gas are being supplied. As such, an etching delay may occur when the flow rate of the Ar gas or the N2gas is large. In such a case, a processing time may be adjusted in anticipation of the etching delay in advance.

As described above, the substrate process step S2is ended by performing the independent substrate processing mode-based process S2-2followed by the common substrate processing mode-based process S2-2. In some embodiments, after the common substrate processing mode-based process S2-2, the independent substrate processing mode-based process S2-1and the common substrate processing mode-based process S2-2may be repeated while performing a purging process between the process S2-1and the process S2-2.

A specific gas flow control in this example will be described with reference to a timing chart ofFIG.6. First, the opening/closing valves151a,151b,151e,151f,151gand151hare opened so that the Ar gas, the N2gas and the NH3gas are supplied to the processing parts11aand11bat the predetermined same flow rates to adjust internal pressures of the processing parts11aand11bto a predetermined pressure, thereby stabilizing the internal pressures (in the pressure stabilizing step S1).

At the point of time when the pressure is stabilized, the substrate process is started (in the substrate process step S2). In the substrate process step S2, first, the opening/closing valve151cis opened to supply the HF gas to the processing part11ato start the COR process in the processing part11a, and then the independent substrate processing mode-based process S2-1with no COR process is performed for a predetermined period of time without supplying the HF gas to the processing part11b. At this time, since the HF gas is not supplied to the processing part11b, the Ar gas of the processing part11bis increased in flow rate more than that of the processing part11aso that the processing part11bhas the same internal pressure as the processing part11a. The Ar gas of the increased flow rate serves as a supplement gas. The increase in amount of the Ar gas (the flow rate of the supplement gas) may correspond to the amount of the HF gas supplied to the processing part11a.

After the predetermined period of time, the COR process is continued in the processing part11awhile maintaining all the gases at the same flow rates, and the common substrate processing mode-based process S2-2with the COR process is performed in the processing part11bfor a predetermined period of time by opening the opening/closing valve151dto supply the HF gas to the processing part11b. At this time, in the processing part11b, the flow rate of the Ar gas supplied in the independent substrate processing mode-based process S2-1is decreased so that the processing part11bhas the same internal pressure as the processing part11a. In this case, the decrease in the amount of the Ar gas may correspond to the amount of the HF gas supplied to the processing part11b.

After the substrate process step S2is completed, all the opening/closing valves are closed to stop the supply of the gases and the process spaces S are exhausted by the exhaust mechanism15(in the exhausting step S3).

In the example ofFIG.6, the HF gas is not introduced into the processing part11bin the independent substrate processing mode-based process S2-1, but the HF gas is introduced into the processing part11bin the common substrate processing mode-based process S2-2. In some embodiments, the HF gas and the NH3gas may not be introduced into the processing part11bin the independent substrate processing mode-based process S2-1, but the HF gas and the NH3gas may be introduced into the processing part11bwhen switching to the common substrate processing mode-based process S2-2. In this case, in the independent substrate processing mode-based process S2-1, the supplement gases to be supplied to the processing part11bmay be the Ar gas and the N2gas.

The result of confirming the effects of the method of this example will be described. Here, etching (COR process) was performed by the processing apparatus ofFIG.1. First, a processing recipe for cyclically etching a CVD-SiO2film in 6 sec×8 cycle was used to evaluate an etching result for a case (process A) where the etching was performed in the order of the common substrate processing mode→the independent substrate processing mode in each cycle and a case (process B) where the etching was performed in the order of the independent substrate processing mode→the common substrate processing mode in each cycle. As described above, the Ar gas, the HF gas, the N2gas and the NH3gas were supplied to both the processing parts11aand11bto perform the COR process in the common substrate processing mode, and the COR process was performed in only the processing part11ain the independent substrate processing mode without supplying the HF gas to the processing part11b. That is to say, in the process A, the COR process was initially performed and subsequently the process was stopped in the processing part11bin each cycle, whereas, in the processing B, the COR process was performed after initially stopping the process for a predetermined period of time in the processing part11bin each cycle.

As a result, in the process A, the etching amount was +36.6% for the target, whereas, in the processing B, the etching amount was −10.4% for the target. From this fact, it was confirmed that the controllability of the etching amount is improved by initially performing the independent substrate processing mode-based process and then performing the common substrate processing mode-based process.

Next, a processing recipe for cyclically etching a thermal oxide film in 15 sec×5 cycle was used to evaluate an etching result for a case (process C) where the etching was performed in the order of the common substrate processing mode→the independent substrate processing mode in each cycle and a case (process D) where the etching was performed in the order of the independent substrate processing mode→the common substrate processing mode in each cycle.

As a result, in the process C, the etching amount was +12.7% for the target, whereas, in the process D, the etching amount was −5.0% for the target. Similarly in the thermal oxide film, from this fact, it was confirmed that the controllability of the etching amount is improved by initially performing the independent substrate processing mode-based process and then performing the common substrate processing mode-based process.

(Another Example of Process Sequence)

In the aforementioned example of the process sequence, in the independent substrate processing mode-based process S2-1, the Ar gas and the N2gas are increased to function as supplement gases in the processing part to which the processing gases (the HF gas and the NH3gas) are not supplied, so that a pressure difference is prevented from occurring between the processing part11aand the processing part11b. This prevents the inflow of the gases between the processing parts11aand11b. However, since the processing parts11aand11bare interconnected via the slits formed in the portions of the inner walls71aand71bbelow the substrate mounting tables61aand61b, it is difficult to completely prevent a backward flow of the processing gases (the HF gas and the NH3gas) from one processing part to the other processing part and completely prevent a backward flow of the supplement gases (the Ar gas and the N2gas) from the other processing part to one processing part. Thus, a backward flow of tiny amounts of gases (gas backward diffusion) occurs. When the flow rates of the processing gases are equal to or higher than a certain level, such a backward flow of tiny amounts of gases does not greatly affect the etching amount, which makes it possible to realize a process with a desired etching amount in the processing parts11aand11b. However, in the process of a low flow rate region, the influence of such a gas backward flow cannot be ignored and a deviation from a set etching amount becomes large, which may make it impossible to perform a desired process in the processing parts11aand11bindependently of each other.

On the other hand, if the flow rates of the processing gases (the HF gas and the NH3gas) and the supplement gases (the Ar gas and the N2gas) are increased in order to avoid such a problem, the etching rate increases and it is therefore necessary to adjust the etching amount with the processing time and the gas flow rate, which may result in a narrow process margin.

Therefore, in this example, during the pressure stabilizing step S1, a pressure regulating gas is flowed at a sufficient flow rate to prevent the processing gases and the supplement gases from backwardly diffusing between the processing parts11aand11bin the independent substrate processing mode-based process S2-2of the subsequent substrate process step S2, and to form a flow of gas flowing from the gas introducing members12aand12bto the exhaust mechanism15. This effectively prevents the backward flow (backward diffusion) of gases in the low flow rate region in the independent substrate processing mode-based process S2-2of the substrate process step S2.

Specifically, as illustrated in a timing chart ofFIG.7, the Ar gas, the N2gas and the NH3gas are supplied as the pressure regulating gases to both the processing parts11aand11bduring the pressure stabilizing step S1. The flow rates of the Ar gas, the N2gas and the NH3gas are set to be larger than those in the substrate process step S2. In this case, the total flow rate of the pressure regulating gases may be three times or more as large as that in the substrate process step S2. As the pressure regulating gas, a portion of the gases supplied during the substrate process step S2, which does not cause substrate process, may be used. As in the example ofFIG.6, as the pressure regulating gases, the Ar gas, the N2gas and the NH3gas may be used in the processing part11a, and the Ar gas and the N2gas may be used in the processing part11b.

In this example, in the subsequent substrate process step S2, in the independent substrate processing mode-based process S2-1, the flow rates of the Ar gas, the N2gas and the NH3gas are decreased until reaching a normal state, and the HF gas is supplied at a predetermined flow rate to perform the COR process in the processing part11a, whereas the flow rates of the N2gas and the NH3gas in the processing part11bare set to be equal to those in the processing part11a. The supply amount of the Ar gas is adjusted so as to include a supplement gas corresponding to the HF gas supplied to the processing part11a. In the subsequent common substrate processing mode-based process S2-2, the HF gas is also supplied to the processing part11b, the flow rate of the Ar gas supplied as a supplement gas is reduced by the supply amount of the HF gas. Thus, the COR process is performed in the processing parts11aand11bunder the same processing conditions. Thereafter, the supply of the gases is stopped and the exhausting step S3is performed to exhaust the process spaces S by the exhaust mechanism15.

Thus, in the low flow rate region, in the independent substrate processing mode-based process S2-2, it is possible to prevent the backward flow of the processing gases and the supplement gases more effectively than that in a case of only adjusting the pressure with the supplement gases. More specifically, even in the low flow rate region, it is possible to extremely effectively prevent the processing gases (the HF gas and the NH3gas) from flowing backward from the processing part11ato the processing part11bintended to stop the process, and also prevent the supplement gases (the Ar gas and the N2gas) from flowing backward from the processing part11bto the processing part11aintended to continue the process. It is therefore possible to perform the substrate process so that the etching amount is close to the etching amount set in both the processing parts11aand11b.

In the example ofFIG.7, the HF gas is not introduced into the processing part11bin the independent substrate processing mode-based process S2-1, whereas the HF gas is introduced into the processing part11bin the common substrate processing mode-based process S2-2. However, the HF gas and the NH3gas may not be introduced into the processing part11bin the independent substrate processing mode-based process S2-1. The HF gas and the NH3gas may be introduced into the processing part11bwhen switching to the common substrate processing mode-based process S2-2. In this case, in the independent substrate processing mode-based process S2-1, the supplement gases supplied to the processing part11bmay be the Ar gas and the N2gas.

The effects achieved when the flow rate of the pressure regulating gas is actually increased in the pressure stabilizing step will be described with reference toFIG.8. Here, after performing the pressure stabilizing step using the apparatus ofFIG.1, the COR process was initially performed in the processing part11ain the substrate process step. The HF gas was not supplied to the processing part11b, and the independent substrate processing mode-based process was performed to supplement an Ar gas as a supplement gas at a flow rate corresponding to the amount of the not-supplied HF gas. Therefore, the COR process was performed in both the processing parts in the common substrate processing mode.FIG.8is a view illustrating the total gas flow rate during the substrate process step and an etching amount deviation (a difference between the actual etching amount and the set etching amount) in the COR process in the processing part11a. InFIG.8, a black circle indicates an etching amount deviation when the flow rates of the pressure regulating gases (the Ar gas, the N2gas and the NH3gas) in the pressure stabilizing step are set to be equal to those in the substrate process step. The etching amount deviation tends to be large in a region where the total flow rate is low. The etching amount deviation is as large as about −0.33 nm at the total flow rate of 300 sccm. On the other hand, a black square indicates an etching amount deviation available when the flow rates of the pressure regulating gases are tripled. In this case, even when the total flow rate during the substrate process step is 300 sccm, the etching amount deviation is about −0.03 nm, which is very close to the set value. The effect of increasing the flow rates of the pressure regulating gases was confirmed from this fact.

As described above, when the COR process is performed on a SiO2film formed on a wafer using the HF gas and the NH3gas, ammonium fluorosilicate ((NH4)2SiF6: AFS) is generated as a reaction product. Thus, the wafer processed in the COR processing apparatus100is heat-treated in a heat treating apparatus to decompose and remove the AFS.

As described above, according to the present embodiment, in performing the COR process on the two wafers respectively in the processing part11aand the processing part11b, while the exhaust mechanism15is used in a collective manner, the process is initially performed in only one of the processing part11aand the processing part11bin the independent substrate processing mode, and subsequently, the COR process is performed in the processing parts in the common substrate processing mode under the same conditions. This improves the controllability of the etching amount.

<Other Applications>

Although the present disclosure has been described by way of an embodiment, the present disclosure is not limited to the above embodiment but various modifications can be made without departing from the spirit and scope of the present disclosure.

While in the above embodiment, the HF gas and the NH3gas have been described to be used to perform the COR process, the COR process may be performed with only the HF gas or the NH3gas by the substrate processing device ofFIG.1. For example, in a case in which an HF gas diluted with an Ar gas is supplied to perform the COR process, the opening/closing valves may be controlled as shown in the following Case d. Specifically, the independent substrate processing mode-based process may be performed using the HF gas only in the processing part11a. Subsequently, with the opening/closing valves151e,151f,151gand151hclosed, the opening/closing valves151a,151b,151cand151dmay be opened to supply the HF gas and the Ar gas to perform the common substrate processing mode-based process.

[Cased]

Supply System to Gas Introduction Member12a

Opening/closing valve 151a (Ar)OpenedOpening/closing valve 151c (HF)OpenedOpening/closing valve 151e (N2)ClosedOpening/closing valve 151g (NH3)Closed
Supply System to Gas Introduction Member12b

Opening/closing valve 151b (Ar)OpenedOpening/closing valve 151d (HF)ClosedOpening/closing valve 151f (N2)ClosedOpening/closing valve 151h (NH3)Closed

In addition, the substrate processing device is not limited to the COR processing apparatus100ofFIG.1as long as it is schematically configured as illustrated inFIG.9such that the processing parts11aand11bare installed in a single common chamber10and the exhaust mechanism15is shared by the processing parts11aand11binstalled inside the single common chamber10.

Further, the present disclosure is limited to the configuration ofFIG.9where the processing parts11aand11bare installed inside the single common chamber10. As an example, as illustrated inFIG.10, the processing parts11aand11bmay be respectively installed inside separate chambers10aand10b, and the exhaust mechanism15may be shared by the separate chambers10aand10b.

While in the above embodiment, the Ar gas or the N2gas, which is a dilution gas for diluting the processing gas such as the HF gas or the NH3gas, is used as a supplement gas for pressure regulation, but the present disclosure is limited to thereto. As an example, the supplement gas may be another inert gas. In addition, the supplement gas for pressure regulation is not limited to the inert gas but may be a non-reactive gas which is not reactive with etching target films of processed wafers Wa and Wb. Further, a reactive gas may be used as long as it can regulate the pressure without affecting the process.

In the above embodiment, the dilution gas is used as a supplement gas for pressure regulation together with the processing gas during the substrate process. However, separately from the dilution gas used together with the processing gas, a dedicated supplement gas may be used. In this case, a dedicated supplement gas supply source, a dedicated supplement gas supply pipe and dedicated MFCs and dedicated opening/closing valves may be additionally installed in the gas supply mechanism14.

Further, in the above embodiment, a semiconductor wafer has been described as an example of a target substrate. However, it is obvious that the target substrate is not limited to the semiconductor wafer in the principle of the present disclosure and it is to be understood that it can be applied to different various substrate processes.

Furthermore, in the above embodiment, the apparatus provided with the two processing parts11aand11bas a plurality of processing parts has been described as an example, but the number of processing parts is not limited to two.

Moreover, in the above embodiment, the substrate processing device of the present disclosure has been described to be applied as the COR processing apparatus, but the substrate processing device is not limited to the COR processing apparatus.

EXPLANATION OF REFERENCE NUMERALS

10,10a,10b: chamber,11a,11b: processing part,12a,12b: gas introduction member,14: gas supply mechanism,15: exhaust mechanism,16: control part,71a,71b: inner wall,101: exhaust pipe,141: Ar gas supply source,142: HF gas supply source,143: N2gas supply source,144: NH3gas supply source,145,145a,145b: HF gas supply pipe,146a,146b: supply pipe,147,147a,147b: Ar gas supply pipe,148,148a,148b: NH3gas supply pipe,149,149a,149b: N2gas supply pipe,150ato150h: mass flow controller,151ato151h: opening/closing valve