Patent ID: 12255072

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments.

One or some embodiments of the present disclosure will now be described with reference toFIGS.1to5D. The drawings used in the following description are all schematic, and the dimensional relationship, ratios, and the like of various elements shown in figures do not always match the actual ones. Further, the dimensional relationship, ratios, and the like of various elements between plural figures do not always match each other.

(1) Configuration of Substrate Processing Apparatus

A substrate process apparatus10includes a process furnace202in which a heater207as a heating means (a heating mechanism or a heating system) is provided. The heater207has a cylindrical shape and is vertically installed by being supported on a heater base (not shown) as a holding plate.

An outer tube203, which constitutes a process container, is disposed inside the heater207to be concentric with the heater207. The outer tube203is made of, for example, a heat resistant material such as quartz (SiO2) or silicon carbide (SiC), and is formed in a cylindrical shape with its upper end closed and its lower end opened. A manifold (inlet flange)209is disposed below the outer tube203to be concentric with the outer tube203. The manifold209is made of, for example, a metal material such as stainless steel (SUS), and is formed in a cylindrical shape with its upper and lower ends opened. An O-ring220aserving as a seal member is installed between the upper end portion of the manifold209and the outer tube203. As the manifold209is supported by the heater base, the outer tube203becomes a state that is vertically installed.

An inner tube204constituting the process container is disposed inside the outer tube203. The inner tube204is made of, for example, a heat resistant material such as quartz (SiO2) or silicon carbide (SiC), and is formed in a cylindrical shape with it upper end closed and its lower end opened. The process container mainly includes the outer tube203, the inner tube204, and the manifold209. A process chamber201is formed in a hollow cylindrical portion (an inside of the inner tube204) of the process container.

The process chamber201is configured to be capable of accommodating wafers200as substrates in a state where the wafers200are arranged in a horizontal posture and in multiple stages in the vertical direction by a boat217which will be described later.

Nozzles410,420, and430are provided in the process chamber201so as to penetrate through a sidewall of the manifold209and the inner tube204. Gas supply pipes310,320, and330are connected to the nozzles410,420, and430, respectively. However, the process furnace202of the present embodiment is not limited to the above-described shape.

Mass flow controllers (MFCs)312,322, and332, which are flow rate controllers (flow rate control parts), are provided in the gas supply pipes310,320, and330, respectively, sequentially from the upstream side. Further, valves314,324, and334, which are opening/closing valves, are provided in the gas supply pipes310,320, and330, respectively. A gas supply pipe340is connected to the downstream side of the valve324of the gas supply pipe320. A MFC342and a valve344are provided in the gas supply pipe340sequentially from the upstream side. Gas supply pipes510,520, and530for supplying an inert gas are connected at the downstream side of the valves314,324, and334of the gas supply pipes310,320, and330(in the gas supply pipe320, further the downstream side of a merging part with the gas supply pipe340), respectively. MFCs512,522, and532, which are flow rate controllers (flow rate control parts), and valves514,524, and534, which are opening/closing valves, are provided in the gas supply pipes510,520, and530, respectively, sequentially from the upstream side.

The nozzles410,420, and430are connected to the leading ends of the gas supply pipes310,320, and330, respectively. The nozzles410,420, and430are configured as L-shaped nozzles, and their horizontal portions are formed so as to penetrate through the sidewall of the manifold209and the inner tube204. The vertical portions of the nozzles410,420, and430are formed inside a channel-shaped (groove-shaped) preliminary chamber201aformed so as to protrude outward in the radial direction of the inner tube204and extend in the vertical direction thereof and are also formed in the preliminary chamber201atoward the upper side (upper side in the arrangement direction of the wafers200) along the inner wall of the inner tube204.

The nozzles410,420, and430are provided so as to extend from a lower region of the process chamber201to an upper region of the process chamber201, and a plurality of gas supply holes410a,420a, and430aare formed at positions facing the wafers200, respectively. Thus, a process gas is supplied from the gas supply holes410a,420a, and430aof the respective nozzles410,420, and430to the wafers200. A plurality of gas supply holes410a,420a, and430aare formed from a lower portion of the inner tube204to an upper portion thereof and have the same aperture area at the same aperture pitch. However, the gas supply holes410a,420a, and430aare not limited to the above-described shape. For example, the aperture area may be gradually increased from the lower portion of the inner tube204to the upper portion thereof. This makes it possible to make the flow rate of the gas supplied from the gas supply holes410a,420a, and430amore uniform.

The plurality of gas supply holes410a,420a, and430aof the nozzles410,420, and430are formed at height positions from a lower portion of the boat217, which will be described later, to an upper portion thereof. Therefore, the process gas supplied into the process chamber201from the gas supply holes410a,420a, and430aof the nozzles410,420, and430is supplied to the entire region of the wafers200accommodated from the lower portion of the boat217to the upper portion thereof. The nozzles410,420, and430are provided so as to extend from the lower region of the process chamber201to the upper region thereof, but may be provided so as to extend to the vicinity of the ceiling of the boat217.

As a process gas, a first gas containing a group XIV element is supplied from the gas supply pipe310into the process chamber201via the MFC312, the valve314, and the nozzle410.

As a process gas, a halogen-containing gas containing a halogen is supplied from the gas supply pipe320into the process chamber201via the MFC322, the valve324, and the nozzle420.

As a process gas, an oxygen-containing gas is supplied from the gas supply pipe330into the process chamber201via the MFC332, the valve334, and the nozzle430.

As a process gas, a hydrogen-containing gas is supplied from the gas supply pipe340into the process chamber201via the MFC342, the valve344, the gas supply pipe320, and the nozzle420.

In the present disclosure, a gas obtained by combining a halogen-containing gas and a hydrogen-containing gas supplied into the process chamber201via the nozzle420is used as a second gas.

As an inert gas, for example, a nitrogen (N2) gas is supplied from the gas supply pipes510,520, and530to the process chamber201via the MFCs512,522, and532, the valves514,524, and534, and the nozzles410,420, and430, respectively. Hereinafter, an example in which the N2gas is used as the inert gas will be described. However, as the inert gas, in addition to the N2gas, it may be possible to use, for example, a rare gas such as an argon (Ar) gas, a helium (He) gas, a neon (Ne) gas, a xenon (Xe) gas, or the like.

A process gas supply system mainly includes the gas supply pipes310,320,330, and340, the MFCs312,322,332, and342, the valves314,324,334, and344, and the nozzles410,420, and430. However, it may be considered that the process gas supply system includes only the nozzles410,420, and430. The process gas supply system may be simply referred to as a gas supply system. When the first gas flows from the gas supply pipe310, a first gas supply system mainly includes the gas supply pipe310, the MFC312, and the valve314. However, it may be considered that the first gas supply system includes the nozzle410. Further, the first gas supply system may be simply referred to as a group XIV element-containing gas supply system. Further, when the halogen-containing gas and the hydrogen-containing gas flow from the gas supply pipe320, a halogen-containing gas supply system mainly includes the gas supply pipe320, the MFC322, and the valve324, a hydrogen-containing gas supply system mainly includes the gas supply pipe340, the MFC342, and the valve344, and a second gas supply system mainly includes the halogen-containing gas supply system and the hydrogen-containing gas supply system. However, it may be considered that the second gas supply system includes the nozzle420. Further, when the oxygen-containing gas flows from the gas supply pipe330, an oxygen-containing gas supply system mainly includes the gas supply pipe330, the MFC332, and the valve334. However, it may be considered that the oxygen-containing gas supply system includes the nozzle430. Further, an inert gas supply system mainly includes the gas supply pipes510,520, and530, the MFCs512,522, and532, and the valves514,524, and534.

A method of supplying a gas in the present disclosure is performed by transferring a gas via the nozzles410,420, and430arranged in the preliminary chamber201ain an annular vertically long space, which is defined by the inner wall of the inner tube204and the ends of a plurality of wafers200. Then, the gas is discharged into the inner tube204from the plurality of gas supply holes410a,420a, and430aformed at positions of the nozzles410,420, and430, which face the wafers. More specifically, the process gas or the like is discharged toward a direction parallel to the surface of the wafers200by the gas supply hole410aof the nozzle410, the gas supply hole420aof the nozzle420, and the gas supply hole430aof the nozzle430.

An exhaust hole (exhaust port)204ais a through-hole formed in a sidewall of the inner tube204at a position facing the nozzles410,420, and430. For example, the exhaust hole204ais a slit-shaped through-hole formed elongated in the vertical direction. A gas supplied into the process chamber201from the gas supply holes410a,420a, and430aof the nozzles410,420, and430and flowing on the surface of the wafers200passes through the exhaust hole204aand flows into an exhaust passage206constituted by a gap formed between the inner tube204and the outer tube203. Then, the gas flowing into the exhaust passage206flows into an exhaust pipe231and is discharged to the outside of the process furnace202.

The exhaust hole204ais formed at a position facing the plurality of wafers200, and a gas supplied from the gas supply holes410a,420a, and430ato the vicinity of the wafers200in the process chamber201flows toward the horizontal direction and then flows into the exhaust passage206through the exhaust hole204a. The exhaust hole204ais not limited to the slit-shaped through-hole, but may be configured by a plurality of holes.

The exhaust pipe231for exhausting an internal atmosphere of the process chamber201is provided in the manifold209. A pressure sensor245, which is a pressure detector (pressure detecting part) for detecting an internal pressure of the process chamber201, an auto pressure controller (APC) valve243, and a vacuum pump246as a vacuum-exhausting device, are connected to the exhaust pipe231sequentially from the upstream side. By opening or closing the APC valve243while the vacuum pump246is actuated, it is capable of performing or stopping a vacuum-exhausting operation in the process chamber201. Further, by adjusting an opening degree of the APC valve243while the vacuum pump246is actuated, it is capable of adjusting the internal pressure of the process chamber201. An exhaust system mainly includes the exhaust hole204a, the exhaust passage206, the exhaust pipe231, the APC valve243, and the pressure sensor245. The exhaust system may include the vacuum pump246.

A seal cap219serving as a furnace opening cover configured to hermetically seal a lower end opening of the manifold209is provided under the manifold209. The seal cap219is configured to come into contact with the lower end of the manifold209from the lower side in the vertical direction. The seal cap219is made of, for example, metal such as stainless steel (SUS), and is formed in a disc shape. An O-ring220bas a seal member making contact with the lower end of the manifold209is provided on an upper surface of the seal cap219. A rotator267for rotating the boat217in which the wafers200are accommodated is installed on the opposite side of the process chamber201with respect to the seal cap219. A rotary shaft255of the rotator267penetrates through the seal cap219and is connected to the boat217. The rotator267is configured to rotate the wafers200by rotating the boat217. The seal cap219is configured to be vertically moved up and down by a boat elevator115as an elevation mechanism vertically installed outside the outer tube203. The boat elevator115is configured to be capable of loading/unloading the boat217into/from the process chamber201by moving the seal cap219up and down. The boat elevator115is configured as a transfer device (transfer system) which transfers the boat217and the wafers200accommodated in the boat217into/out of the process chamber201.

The boat217serving as a substrate support is configured to arrange a plurality of wafers200, for example, 25 to 200 wafers200, at intervals in the vertical direction in a horizontal posture with the centers of the wafers200aligned with one another. The boat217is made of, for example, a heat resistant material such as quartz or SiC. Heat insulating plates218made of, for example, a heat resistant material such as quartz or SiC, are installed in a horizontal posture and in multiple stages (not shown) below the boat217. This configuration makes it difficult to transfer heat from the heater207to the seal cap219side. However, the present embodiment is not limited to the above-described form. For example, instead of installing the heat insulating plates218, a heat insulating cylinder configured as a cylindrical member made of a heat resistant material such as quartz or SiC may be installed below the boat217.

As shown inFIG.2, a temperature sensor263serving as a temperature detector is installed in the inner tube204. Based on temperature information detected by the temperature sensor263, a state of supplying electric power to the heater207is adjusted such that the interior of the process chamber201has a desired temperature distribution. The temperature sensor263is configured as an L-shape, like the nozzles410,420, and430, and is provided along the inner wall of the inner tube204.

As shown inFIG.3, a controller121, which is a control part (control means), may be configured as a computer including a central processing unit (CPU)121a, a random access memory (RAM)121b, a memory121c, and an I/O port121d. The RAM121b, the memory121c, and the I/O port121dare configured to be capable of exchanging data with the CPU121avia an internal bus. An input/output device122formed of, for example, a touch panel or the like, is connected to the controller121.

The memory121cis configured by, for example, a flash memory, a hard disk drive (HDD), or the like. A control program for controlling operations of a substrate processing apparatus and a process recipe in which sequences and conditions of a method of manufacturing a semiconductor device, which will be described later, are written, are readably stored in the memory121c. The process recipe functions as a program for causing the controller121to execute each step in the method of manufacturing a semiconductor device, which will be described later, to obtain a predetermined result. Hereinafter, the process recipe and the control program may be generally and simply referred to as a “program.” When the term “program” is used herein, it may indicate a case of including the process recipe only, a case of including the control program only, or a case of including a combination of the process recipe and the control program. The RAM121bis configured as a memory area (work area) in which a program or data read by the CPU121ais temporarily stored.

The I/O port121dis connected to the MFCs312,322,332,342,512,522, and532, the valves314,324,334,344,514,524, and534, the pressure sensor245, the APC valve243, the vacuum pump246, the heater207, the temperature sensor263, the rotator267, the boat elevator115, and the like.

The CPU121ais configured to read and execute the control program from the memory121c. The CPU121ais also configured to read the recipe from the memory121caccording to an input of an operation command from the input/output device122. The CPU121ais configured to be capable of controlling the flow rate adjustment operation of various kinds of gases by the MFCs312,322,332,342,512,522, and532, the opening/closing operation of the valves314,324,334,344,514,524, and534, the opening/closing operation of the APC valve243, the pressure adjusting operation performed by the APC valve243based on the pressure sensor245, the temperature adjusting operation performed by the heater207based on the temperature sensor263, the actuating and stopping of the vacuum pump246, the operation of rotating the boat217with the rotator267and adjusting the rotation speed of the boat217, the operation of moving the boat217up and down by the boat elevator115, the operation of accommodating the wafers200in the boat217, and the like, according to contents of the read recipe.

The controller121may be configured by installing, on the computer, the aforementioned program stored in an external memory (for example, a magnetic tape, a magnetic disk such as a flexible disk or a hard disk, an optical disc such as a CD or a DVD, a magneto-optical disc such as a MO, or a semiconductor memory such as a USB memory or a memory card)123. The memory121cand the external memory123are configured as a non-transitory computer-readable recording medium. Hereinafter, the memory121cand the external memory123may be generally and simply referred to as a “recording medium.” When the term “recording medium” is used herein, it may indicate a case of including the memory121conly, a case of including the external memory123only, or a case of including both the memory121cand the external memory123. The program may be provided to the computer using a communication means such as the Internet or a dedicated line, instead of using the external memory123.

(2) Substrate Processing Process

As one process of manufacturing a semiconductor device, an example of a process (etching method) of etching a group XIV element-containing film containing a group XIV element such as silicon (Si), which is formed on a wafer200, will be described with reference toFIGS.4and5A to5D. This process is performed using the process furnace202of the above-described substrate processing apparatus10. In the following description, the operations of various parts constituting the substrate processing apparatus10can be controlled by the controller121.

A substrate processing process (a process of manufacturing a semiconductor device) according to the present disclosure includes:(a) a step of supplying a first gas containing a group XIV element to a wafer200which is arranged in a process container and on which a film containing the group XIV element is formed such that reaction by-products generated by reaction with the group XIV element contained in the film formed on the wafer200are saturated and adsorbed on the wafer200;(b) a step of supplying a second gas containing a halogen after (a); and(c) a step of etching the film containing the group XIV element formed on the wafer200by alternately repeating (a) and (b).

When the term “wafer” is used in the present disclosure, it may refer to “a wafer itself” or “a wafer and a laminated body of certain layers or films formed on a surface of a wafer.” When the phrase “a surface of a wafer” is used in the present disclosure, it may refer to “a surface of a wafer itself” or “a surface of a certain layer or film formed on a wafer”. When the term “substrate” is used in the present disclosure, it may be synonymous with the term “wafer.”

(Wafer Loading)

When a plurality of wafers200is charged in the boat217(wafer charging), as shown inFIG.1, the boat217supporting the plurality of wafers200is lifted up by the boat elevator115and is loaded into the process chamber201(boat loading) and arranged in the process container. In this state, the seal cap219seals the lower end of the outer tube203via the O-ring220.

(Pressure Adjustment and Temperature Adjustment)

The interior of the process chamber201, that is, a space where the wafer200is placed, is vacuum-exhausted by the vacuum pump246to reach a desired pressure (degree of vacuum). At this time, the internal pressure of the process chamber201is measured by the pressure sensor245. The APC valve243is feedback-controlled based on the measured pressure information (pressure adjustment). The vacuum pump246always keeps in operation at least until processing on the wafers200is completed. The interior of the process chamber201is heated by the heater207to a desired temperature. At this time, the state of supplying electric power to the heater207is feedback-controlled based on the temperature information detected by the temperature sensor263such that the interior of the process chamber201has a desired temperature distribution (temperature adjustment). Heating the interior of the process chamber201by the heater207may be continuously performed at least until the processing on the wafers200is completed.

(First Gas (Group XIV Element-Containing Gas) Supply, First Step)

The valve314is opened to allow a first gas to flow into the gas supply pipe310. The flow rate of the first gas is adjusted by the MFC312, and the first gas is supplied into the process chamber201from the gas supply hole410aof the nozzle410and is exhausted through the exhaust pipe231.

At this time, the first gas is supplied such that reaction by-products generated by reaction with a group XIV element contained in a group XIV element-containing film formed on the wafer200is saturated and adsorbed on the wafer200. Here, in the present disclosure, the saturation means that adsorbable sites do not have to be completely filled, but may be substantially saturated. That is, in order to improve productivity, it may be in a state where the adsorbable sites are not completely saturated, in other words, it may be in a state where the reaction is not completely converged. In addition, in a combination of a gas type and a film type having a saturation curve in a region where the characteristic of the reaction amount with respect to the gas supply time is larger than that in a certain supply time, using a state that is not completely saturated on the saturation curve may be referred to as saturated adsorption in the present disclosure. At least one effect of the present disclosure can be obtained with one supply time on the saturation curve. When the supply time is set as the region of the supply time in which such a saturation curve can be obtained, it can also be referred to a supply using the saturated adsorption characteristic.

At this time, the first gas is supplied to the wafer200at an atmosphere in which the first gas is decomposed. The atmosphere in which the first gas is decomposed is a temperature such that the temperature of the wafer200is, for example, within a range of 350 degrees C. to 500 degrees C. Specifically, for example, when a dichlorosilane (SiH2Cl2, abbreviation: DCS) gas is used as the first gas, the atmosphere is a temperature such that the temperature of the wafer200is within the range of 350 degrees C. to 500 degrees C.

That is, the temperature of the heater207is set to a temperature such that the temperature of the wafer200is within the range of, for example, 350 to 500 degrees C. The notation of a numerical range such as “350 to 500 degrees C.” in the present disclosure means that the lower limit value and the upper limit value are included in the range. Therefore, for example, “350 to 500 degrees C.” means “350 degrees C. or higher and 500 degrees C. or lower.” The same applies to other numerical ranges.

At this time, the APC valve243is adjusted such that the internal pressure of the process chamber201is set to, for example, a pressure within a range of 20 to 100 Pa. The supply flow rate of the group XIV element-containing gas, which is controlled by the MFC312is, for example, a flow rate within a range of 0.1 to 1.0 slm. The time for supplying the first gas to the wafer200is, for example, a time within a range of 15 to 30 seconds.

As the first gas, for example, a DCS gas, which is a gas containing silicon (Si) that is a group XIV element, and is a chlorosilane-based gas, can be used.

Specifically, for example, when the DCS gas is used as the first gas and a Si film which is a film containing Si as a main component is used as the group XIV element-containing film, as shown inFIG.5A, by the supply of the DCS gas, the DCS gas is decomposed and adsorbed on the wafer200(base film on the surface thereof) having the Si film formed on the surface thereof. At this time, Si on the surface of the wafer200reacts with Cl decomposed from the DCS gas to generate SiCl which is a reaction by-product. Further, the generated SiCl is dissociated from the surface of the wafer200, and dissociated molecules are polymerized.

Then, as shown inFIG.5B, the dissociated SiCl and the polymerized molecules are re-adsorbed on the wafer200. In this re-adsorption, since the number of adsorbable adsorption sites decreases over time, the amount of adsorption becomes saturated. Such saturation is also called self-limit. That is, a SiCl layer (inhibitor layer) containing SiCl as a main component, such as SiCl2or SiCl4, is generated on the surface of the wafer200. This SiCl layer has an effect of suppressing the adsorption of a newly supplied DCS gas, newly generated dissociated SiCl, and newly generated polymerized molecules, which is called an inhibitor effect, and such a layer is called an inhibitor layer. Here, in an undecomposed gas, since it is difficult to generate SiCl, it is difficult to obtain the inhibitory effect. That is, in the undecomposed gas, physical adsorption of gas molecules themselves occurs, the amount of physical adsorption continues to increase, which leads to a possibility that the physical adsorption is not saturated. In addition, the undecomposed gas reacts with the Si film, and etching continues to proceed, which leads to a possibility that the etching is not stopped. By supplying the Si film on the wafer200at an atmosphere in which the DCS gas is decomposed, Cl contained in the DCS gas can be reacted with Si on the wafer200to promote the generation of SiCl.

(Second Gas (Halogen-Containing Gas and Hydrogen-Containing Gas) Supply, Second Step)

After a predetermined time has elapsed from the start of the supply of the first gas, the valve314is closed to stop the supply of the first gas into the process chamber201. At this time, the valves324and344are opened, and a halogen-containing gas and a hydrogen-containing gas simultaneously flow into the gas supply pipe320. That is, after the supply of the first gas, the supply of a second gas is started without supplying a purge gas.

The flow rates of the halogen-containing gas and the hydrogen-containing gas are adjusted by the MFCs322and342, respectively, and the halogen-containing gas and the hydrogen-containing gas are supplied into the process chamber201from the gas supply hole420aof the nozzle420and are exhausted through the exhaust pipe231. In this operation, the second gas is supplied to the wafer200.

At this time, the second gas, which is a combination of the halogen-containing gas and the hydrogen-containing gas, is supplied to the wafer200at an atmosphere in which the second gas is not decomposed. The atmosphere in which the second gas is not decomposed is a temperature such that the temperature of the wafer200is within a range of, for example, 350 degrees C. to 500 degrees C. Specifically, for example, when a Cl2gas is used as the second gas, the atmosphere is a temperature such that the temperature of the wafer200is within the range of 350 degrees C. to 500 degrees C.

At this time, the APC valve243is adjusted such that the internal pressure of the process chamber201is set to, for example, a pressure within a range of 20 to 100 Pa. The supply flow rate of the halogen-containing gas, which is controlled by the MFC322is, for example, a flow rate within a range of 0.01 to 0.10 slm. The supply flow rate of the hydrogen-containing gas, which is controlled by the MFC342is, for example, a flow rate within a range of 0.1 to 2.0 slm. The time for supplying the halogen-containing gas and the hydrogen-containing gas to the wafer200at the same time is, for example, a time within a range of 2 to 5 seconds.

In this operation, the second gas, which is a mixture of the halogen-containing gas and the hydrogen-containing gas, is supplied to the wafer.

As the second gas, for example, a chlorine (Cl2) gas, which is a halogen-containing gas, and a hydrogen (H2) gas, which is a hydrogen-containing gas, can be used.

Specifically, for example, when the Cl2gas and the H2gas are used as the second gas, as shown inFIG.5C, by the supply of the second gas, a portion of the SiCl layer generated on the surface of the wafer200reacts to produce reaction by-products. That is, Si contained in the SiCl layer is bonded to Cl contained in the Cl2gas or H contained in the H2gas, so that the Si film on the wafer200is etched. Specifically, Si, Cl, and H molecules adsorbed on the wafer200react with the Cl2gas and H2gas as the second gas, so that Si, Cl, or H are dissociated from the SiCl layer and the Si film of the surface of the wafer200is etched. That is, by not decomposing the second gas, Cl2can be supplied to the SiCl layer generated on the surface of the wafer200in the first step, and the removal efficiency of the SiCl layer can be improved. This makes it possible to improve the etching controllability of the Si film.

Here, when purging is performed between the first gas supply and the second gas supply, SiCl adsorbed on the Si film surface is removed and the Si film to be etched is exposed, which makes it difficult to obtain the etching characteristics for each layer and leads to a possibility that the etching rate decreases. By not performing purging between the first gas supply and the second gas supply, the surface of the Si film to be etched is kept covered with SiCl, which makes it easier to obtain the etching effect for each layer. That is, it is possible to improve the etching rate and the in-plane uniformity by etching.

(Purging, Third Step)

After a predetermined time has elapsed from the start of the supply of the second gas, for example, after 1 to 30 seconds, the valves324and344are closed to stop the supply of the second gas. At this time, with the APC valve243of the exhaust pipe231opened, the interior of the process chamber201is vacuum-exhausted by the vacuum pump246to remove a residual gas from the surface of the wafer200, so that an unreacted second gas and reaction by-products remaining in the process chamber201are excluded from the process chamber201. At this time, the valves514,524, and534are opened to supply an inert gas as a purge gas into the process chamber201to purge the interior of the process container. The inert gas acts as a purge gas and can enhance the effect of removing the residual gas from the wafer200, thereby excluding the unreacted second gas and reaction by-products remaining in the process chamber201from the process chamber201. The supply flow rates of the inert gas controlled by the MFCs512,522, and532is, for example, 0.1 to 2.0 slm, respectively.

By performing the purging in this way, as shown inFIG.5D, reaction by-products generated by etching can be removed. Further, when a cycle process is performed, reaction between the second gas, the reaction by-products, and the first gas can be suppressed by performing the purging. In addition, it is possible to prevent the self-limit effect at the time of supplying the first gas from diminishing due to the reaction between the second gas, the reaction by-products, and the first gas. That is, by performing the purging, it is possible to improve the self-limit effect at the time of supplying the first gas.

(Performing Predetermined Number of Times)

By performing a cycle a predetermined number of times (N times), once or more, the cycle including sequentially performing the above-described first to third steps, the film containing the group XIV element formed on the wafer200is etched. That is, by alternately repeating the first to third steps, it is possible to etch the film containing the group XIV element formed on the wafer200.

(After-Purging and Returning to Atmospheric Pressure)

An inert gas is supplied into the process chamber201from each of the gas supply pipes510to530and is exhausted through the exhaust pipe231. The inert gas acts as a purge gas, whereby the interior of the process chamber201is purged with the inert gas to remove a gas and reaction by-products remaining in the process chamber201from the process chamber201(after-purging). After that, the internal atmosphere of the process chamber201is substituted with the inert gas (inert gas substitution), and the internal pressure of the process chamber201is returned to the atmospheric pressure (returning to atmospheric pressure).

(Wafer Unloading)

After that, the seal cap219is moved down by the boat elevator115to open the lower end of the outer tube203. Then, the processed wafers200supported by the boat217are unloaded from the lower end of the outer tube203to the outside of the outer tube203(boat unloading). After that, the processed wafers200are discharged from the boat217(wafer discharging).

(3) Effects of the Present Embodiment

According to the present embodiment, one or more effects set forth below may be achieved.(a) It is possible to enhance the etching controllability of a film containing a group XIV element.(b) It is possible to perform the micro-fabrication of a film containing a group XIV element.

(4) Other Embodiments

The embodiments of the present disclosure have been specifically described above. However, the present disclosure is not limited to the above-described embodiment, and various modifications can be made without departing from the gist thereof.

(Modification 1)

FIG.6shows a modification of the substrate processing sequence according to the embodiments of the present disclosure. In this modification, the group XIV element-containing film formed on the wafer200is etched by performing the cycle a predetermined number of times (N times), once or more, the cycle including sequentially performing the above-described first and second steps. That is, the purging of the above-described third step is not performed. Even in this case, it is possible to etch the film containing the group XIV element.

(Modification 2)

FIG.7shows another modification of the substrate processing sequence according to the embodiments of the present disclosure. In this modification, an oxygen-containing gas is supplied from an oxygen-containing gas supply system after performing the cycle a predetermined number of times (N times), the cycle including sequentially performing the above-described first to third steps. Then, after supplying an inert gas (purge gas), a cycle including sequentially performing the first to third steps is performed a predetermined number of times (M times). That is, in the middle of repeating the above-described first to third steps, the oxygen-containing gas is supplied to oxidize the surface of the wafer200. As a result, the surface of the wafer200is oxidized during the etching, so that excessive etching can be suppressed. In addition, the etching amount (etching film thickness) can be adjusted, so that the etching controllability can be improved.

As the oxygen-containing gas, an oxygen (O2) gas, an ozone (O3) gas, water vapor (1120), or the like can be used.

(Modification 3)

FIGS.8A and8Bshow other modifications of the substrate processing sequence according to the embodiments of the present disclosure. In this modification, as shown inFIG.8A, as the first gas in the above-described first step, a hydrogen-containing gas is supplied in addition to the group XIV element-containing gas. That is, the hydrogen-containing gas is supplied in parallel with the supply of the group XIV element-containing gas in the above-described first step. Then, a halogen-containing gas is supplied as the second gas in the second step. That is, in the second step, the hydrogen-containing gas is not supplied.

Further, as shown inFIG.8B, a hydrogen-containing gas may be supplied in addition to each gas in both the above-described first and second steps. That is, the hydrogen-containing gas may be supplied in parallel with the supply of the group XIV element-containing gas in the first step and the supply of the halogen-containing gas in the second step.

That is, the hydrogen-containing gas is supplied in addition to the supply of each gas in one or both of the first and second steps. As a result, it is possible to perform each step while removing reaction by-products and enhance the etching controllability while improving the processing quality.

As the hydrogen-containing gas, a hydrogen (H2) gas, an activated hydrogen gas, or the like can be used.

(Modification 4)

Next, when a film containing the group XIV element, which is an etching target, is a doped Si film doped with phosphorus (P), which is a predetermined element, and a non-doped Si film not doped with P and the above-described first step to third steps are performed on the wafer200having the doped Si film and the non-doped Si film formed on the surface of the wafer200, the effect of the above-described etching will be described.

First, by the supply of the first gas in the first step, the same reaction as shown inFIGS.5A and5Bin the first step occurs on the doped Si film and the non-doped Si film.

Then, by the supply of the second gas in the second step, a reaction is suppressed on the doped Si film as compared with the non-doped Si film, and a reaction as shown inFIG.5Cin the second step occurs on the non-doped Si film to be etched.

That is, by performing the above-described first to third steps, it is possible to selectively etch the non-doped Si film.

(Modification 5)

Next, when a film containing the group XIV element, which is an etching target, is a crystalline Si film, which is a single crystal Si film or a polycrystalline Si film, and a non-crystalline Si film which is an amorphous Si film, and the above-described first step to third steps are performed on the wafer200having the crystalline Si film and the non-crystalline Si film formed on the surface of the wafer200, the effect of the above-described etching will be described.

Normally, it is easier to etch the non-crystalline Si film than the crystalline Si film. That is, when the etching is performed according to the etching rate of the crystalline Si film, the non-crystalline Si film may be etched more than a predetermined film thickness, resulting in over-etching. It is considered that this is because the etching rate differs depending on the grain boundaries of the crystal and the arrangement of atoms.

By performing the above-described first to third steps, both the crystalline Si film and the non-crystalline Si film are etched. It is considered that this is because the etching by the first gas is self-stopped (saturation-stopped) due to the inhibitor effect, and therefore it is difficult to receive a difference in etching rate due to the crystallinity. That is, according to the present disclosure, it is possible to reduce the difference in etching rate between the crystalline Si film and the non-crystalline Si film, thereby suppressing over-etching.

(Modification 6)

Next, when a film containing the group XIV element, which is an etching target, is a silicon oxide (SiO2) film, which is an oxide film, and a Si film, which is a non-oxide film, and the above-described first step to third steps are performed on the wafer200having the SiO2film and the Si film formed on the surface of the wafer200, the effect of the above-described etching will be described.

By performing the above-described first to third steps, the Si film, which is the non-oxide film, is etched. That is, it is possible to selectively etch the non-oxide film. Here, as the non-oxide film, in addition to the Si film, a doped Si film doped with P, a silicon nitride (SiN) film, or the like can be used.

(Modification 7)

Next, when a film containing the group XIV element, which is an etching target, is a SiN film, which is a nitride film, and a Si film, which is a non-nitride film, and the above-described first step to third steps are performed on the wafer200having the SiN film and the Si film formed on the surface of the wafer200, the effect of the above-described etching will be described.

By performing the above-described first to third steps, the Si film, which is the non-nitride film, is etched. That is, it is possible to selectively etch the non-nitride film.

(Modification 8)

Next, when a film containing the group XIV element, which is an etching target, is a Si film, which is a non-oxide film, and the above-described first step to third steps are performed on the wafer200formed with a laminated film in which the Si film, which is the non-oxide film, is formed on a SiO2film, which is an oxide film, the effect of the above-described etching will be described.

By performing the above-described first to third steps, the Si film, which is the non-oxide film, is etched. That is, the SiO2film, which is the oxide film, becomes an etching stopper, so that it is possible to selectively etch the non-oxide film.

In the above embodiment, the case where the purging is not performed between the first gas supply and the second gas supply has been described, but the present disclosure is not limited thereto. The purging may be performed between the first gas supply and the second gas supply.

Further, in the above embodiment, the case where the Si film is used as the Si-containing film containing Si as a main component, which is a film containing the group XIV element, has been described, but the present disclosure is not limited thereto. As the Si-containing film, a single crystal Si film, a polycrystalline Si film, an amorphous Si film, a SiN film, a doped Si film, a non-doped Si film, or the like can be used.

As the doped Si film, a Si film doped with phosphorus (P) as a dopant or a Si film doped with boron (B) as a dopant can be used.

Further, in the above embodiments, as the film containing the group XIV element, for example, a film containing another group XIV element such as germanium (Ge) can be suitably applied.

Further, in the above embodiments, the case where the DCS gas containing, for example, silicon (Si), is used as the gas containing the group XIV element as the first gas has been described, but the present disclosure is not limited thereto. It can also be suitably applied to a case where a gas containing another group XIV element such as germanium (Ge) is used.

Specifically, as the first gas, for example, a chlorosilane-based gas such as a gas including at least one or more selected from the group of a dichlorosilane (SiH2Cl2, abbreviation: DCS) gas, a hexachlorodisilane (Si2Cl6, abbreviation: HCDS) gas, and silicon tetrachloride (SiCl4) gas can be used. Further, as the first gas, a silane-based gas such as a monosilane (SiH4) gas, a disilane (Si2H6) gas, or a trisilane (Si3H8) gas can be used. More particularly, the chlorosilane-based gas containing Si and Cl, which easily cause a saturation reaction, is used. Further, in the case of the silane-based gas, the effects similar to those of the chlorosilane-based gas can be obtained by supplying the gas in a cycle. That is, the same kind of effects can be obtained when the halogen species of the second gas supplied in the Xthcycle remain until the (X+1)thcycle and thereafter. Here, X is an integer.

As the first gas containing Ge, for example, a chlorogermane-based gas such as a gas including at least one or more selected from the group of a chlorogermane (GeH2Cl2) gas, a hexachlorodigermane (Ge2Cl6, also known as a digermanium hexachloride) gas, and a germanium tetrachloride (GeCl4) gas, can be used. Further, as the first gas containing Ge, a germane-based gas such as a monogerman (GeH4) gas, a digermane (Ge2H6) gas, or a trigermane (Ge3H8) gas can be used. More particularly, the chlorogermane-based gas containing Ge and Cl, which easily cause a saturation reaction, is used. Further, in the case of the germane-based gas, the effects similar to those of the chlorogermane-based gas can be obtained by supplying the gas in a cycle. That is, the same kind of effects can be obtained when the halogen species of the second gas supplied in the Xthcycle remain until the (X+1)thcycle and thereafter. Here, X is an integer.

Further, as the second gas, for example, a combination of at least one selected from the group of a chlorine (Cl2) gas, which is a halogen-containing gas and contains chlorine, a hydrogen chloride (HCl) gas, a boron trichloride (BCl3) gas, a silicon tetrachloride (SiCl4) gas, and a mixture of a monosilane (SiH4) gas and a Cl2gas, and a hydrogen-containing gas, can be used. Further, as the hydrogen-containing gas, a H2gas or the like can be used.

Further, as the second gas, for example, a combination of at least one selected from the group of a chlorine (Cl2) gas, a hydrogen chloride (HCl) gas, a boron trichloride (BCl3) gas, a silicon tetrachloride (SiCl4) gas, and a mixture of a monosilane (SiH4) gas and a Cl2gas, and a fluorine (F)-based gas or a bromine (Br)-based gas, can be used.

Further, the etching selectivity can be improved by using a Cl-based gas containing chlorine as the second gas, but the same effects can be obtained even when an F-based gas or a Br-based gas is used.

Further, as the second gas, a silicon tetrachloride (SiCl4) gas or a monosilane (SiH4) gas may be replaced with a gas such as a germanium tetrachloride (GeCl4) gas or a monogerman (GeH4) gas.

Further, in the above embodiments, the example in which the halogen-containing gas and the hydrogen-containing gas are supplied into the process chamber201via the same nozzle420has been described, but the present disclosure is not limited thereto, and these gases may be supplied from another nozzle.

Further, in the above embodiments, the example in which a film is formed by using the substrate processing apparatus which is a batch-type substrate processing apparatus capable of processing a plurality of substrates at a time has been described, but the present disclosure is not limited thereto. For example, the present disclosure can be suitably applied to even a case where a film is formed by using a single-wafer type substrate processing apparatus capable of processing a single substrate or several substrates at a time.

For example, the present disclosure can be suitably applied to even a case where a film is formed by using a substrate processing apparatus including a process furnace302shown inFIG.9A. The process furnace302includes a process container303forming a process chamber301, a shower head303sthat supplies a gas into the process chamber301in a shower shape, a support317that supports one or several wafers200in a horizontal posture, a rotary shaft355that supports the support317from below, and a heater307provided in the support317. A gas supply port304afor supplying the above-described first gas, a gas supply port304bfor supplying the above-described second gas, and a gas supply port304cfor supplying the above-described third gas are connected to an inlet (gas introduction port) of the shower head303s. A first gas supply system similar to the first gas supply system of the above-described embodiments is connected to the gas supply port304a. A second gas supply system similar to the second gas supply system of the above-described embodiment is connected to the gas supply port304b. An oxygen-containing gas supply system similar to the above-described oxygen-containing gas supply system is connected to the gas supply port304c. A gas dispersion plate that supplies a gas into the process chamber301in a shower shape is provided in an outlet (gas discharge port) of the shower head303s. An exhaust port331for exhausting the interior of the process chamber301is provided in the process container303. An exhaust system similar to the exhaust system of the above-described embodiments is connected to the exhaust port331.

Further, for example, the present disclosure can be suitably applied to even a case where a film is formed by using a substrate processing apparatus including a process furnace402shown inFIG.9B. The process furnace402includes a process container403forming a process chamber401, a support417that supports one or several wafers200in a horizontal posture, a rotary shaft455that supports the support417from below, a lamp heater407that irradiates the wafers200of the process container403with light, and a quartz window403wthat transmits the light of the lamp heater407. A gas supply port432afor supplying the above-described first gas, a gas supply port432bfor supplying the above-described second gas, and a gas supply port432cfor supplying the above-described oxygen-containing gas are connected to the process container403. A first gas supply system similar to the first gas supply system of the above-described embodiments is connected to the gas supply port432a. A second gas supply system similar to the second gas supply system of the above-described embodiments is connected to the gas supply port432b. An oxygen-containing gas supply system similar to the oxygen-containing gas supply system of the above-described embodiment is connected to the gas supply port432c. An exhaust port431for exhausting the interior of the process chamber401is provided in the process container403. An exhaust system similar to the exhaust system of the above-described embodiment is connected to the exhaust port431.

Even when these substrate processing apparatuses are used, etching can be performed under the same sequence and process conditions as those in the above-described embodiments.

It is desirable that a process recipe (a program in which the processing procedure, process conditions, and the like are written) used for these substrate processing is prepared individually (in plural) according to the substrate processing contents (film type, composition ratio, film quality, film thickness, processing procedure, process conditions, and the like of a thin film to be etched). Then, when starting the substrate processing, it is desirable that a proper process recipe is appropriately selected from a plurality of process recipes according to the substrate processing contents. Specifically, it is desirable that the plurality of process recipes individually prepared according to the substrate processing contents are stored (installed) in advance in the memory121cincluded in the substrate processing apparatus via a telecommunication line or a recording medium (the external memory123) on which the process recipes are recorded. Then, when starting the substrate processing, it is desirable that the CPU121aincluded in the substrate processing apparatus appropriately selects a proper process recipe from the plurality of process recipes stored in the memory121caccording to the substrate processing contents. With this configuration, it is possible to form thin films of various film types, composition ratios, film qualities, and film thicknesses with a single substrate processing apparatus in a versatile and well-reproducible manner. Further, it is possible to reduce an operator's operation burden (input burden of processing procedure, process conditions, etc.) and to quickly start the substrate processing while avoiding an operation error.

Further, the present disclosure can also be realized by, for example, changing a process recipe of the existing substrate processing apparatus. When changing a process recipe, the process recipe according to the present disclosure may be installed on the existing substrate processing apparatus via a telecommunications line or a recording medium on which the process recipe is recorded, or it is also possible to change a process recipe of the existing substrate processing apparatus to the process recipe according to the present disclosure by operating an input/output device of the existing substrate processing apparatus.

Although various typical embodiments of the present disclosure have been described above, the present disclosure is not limited to those embodiments, and such embodiments may be used in proper combination.

According to the present disclosure in some embodiments, it is possible to enhance the controllability of etching.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosures. Indeed, the embodiments described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosures. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosures.