Processing method and processing apparatus

A processing method includes a first process of exposing a first sensor to a processing space within a chamber and blocking a second sensor from the processing space within the chamber; a second process of supplying a first processing gas containing a precursor gas into the chamber; a third process of controlling a state within the chamber based on a measurement value of the first sensor; a fourth process of blocking the first sensor from the processing space within the chamber and exposing the second sensor to the processing space within the chamber; a fifth process of supplying a second processing gas containing a reactant gas into the chamber; and a sixth process of controlling the state within the chamber based on a measurement value of the second sensor. The first process to the six process are repeatedly performed multiple times.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Japanese Patent Application No. 2016-232642 filed on Nov. 30, 2016, the entire disclosures of which are incorporated herein by reference.

TECHNICAL FIELD

The embodiments described herein pertain generally to a processing method and a processing apparatus.

BACKGROUND

As one of methods for forming a film on a substrate, there is known an atomic layer deposition (ALD) method. In the ALD method, as a precursor gas is supplied into a chamber in which a processing target substrate is accommodated, atoms or molecules of the precursor gas containing a constitution element of a thin film are adsorbed onto the processing target substrate. Then, the atoms or molecules of the precursor gas excessively adsorbed on the processing target substrate is removed by a purge gas supplied into the chamber. Thereafter, a reactant gas containing a constituent element of the thin film is supplied into the chamber, and the processing target substrate having the atoms or molecules of the precursor gas adsorbed thereto is exposed to active species of the reactant gas, so that the required thin film is formed on the processing target substrate. The active species of the reactant gas are generated by, for example, plasma. In the ALD method, as a cycle including a single adsorption process and a single reaction process is repeated multiple times, a film of the atoms or molecules contained in the precursor gas is deposited on the substrate layer by layer.

In each process of the film formation using the ALD method, a state within the chamber such as a pressure therein is controlled based on a measurement value measured by various kinds of sensors such as a pressure gauge. In many cases, however, sensor surfaces of such sensors may be exposed to a processing space within the chamber. As a result, the same as the film is formed on the processing target substrate, a reaction product caused by the precursor gas and the reactant gas is also deposited on the sensor surfaces of the sensors which are exposed to the processing space within the chamber. Accordingly, as the cycle of the ALD is repeated, sensitivity of the sensors may be deteriorated, and accuracy of various kinds of measurement values measured by the sensors may be degraded. Thus, it may be difficult to control the state within the chamber to a required state, and accuracy, such as the quality of the film formed on the processing target substrate, may be degraded.

SUMMARY

In one exemplary embodiment, a processing method includes a first process of exposing a first sensor to a processing space within a chamber and blocking a second sensor from the processing space within the chamber; a second process of supplying a first processing gas containing a precursor gas into the chamber; a third process of controlling a state within the chamber based on a measurement value of the first sensor; a fourth process of blocking the first sensor from the processing space within the chamber and exposing the second sensor to the processing space within the chamber; a fifth process of supplying a second processing gas containing a reactant gas into the chamber; and a sixth process of controlling the state within the chamber based on a measurement value of the second sensor. The first process to the six process are repeatedly performed multiple times.

In the present disclosure, a processing method includes a first process of exposing a first sensor to a processing space within a chamber and blocking a second sensor from the processing space within the chamber; a second process of supplying a first processing gas containing a precursor gas into the chamber; a third process of controlling a state within the chamber based on a measurement value of the first sensor; a fourth process of blocking the first sensor from the processing space within the chamber and exposing the second sensor to the processing space within the chamber; a fifth process of supplying a second processing gas containing a reactant gas into the chamber; and a sixth process of controlling the state within the chamber based on a measurement value of the second sensor. Here, the first process to the six process are repeatedly performed multiple times.

The processing method may further include a seventh process of generating plasma of the second processing gas within the chamber after the sixth process. The first process to the seventh process are repeatedly performed multiple times.

The processing method may further include an eighth process of, after the first process to the seventh process are repeatedly performed a preset number of times, blocking the first sensor from the processing space within the chamber and exposing the second sensor to the processing space within the chamber after the seventh process; a ninth process of supplying a third processing gas containing an etching gas into the chamber; a tenth process of controlling the state within the chamber based on a measurement value of the second sensor; and an eleventh process of generating plasma of the third processing gas within the chamber.

The precursor gas may be a gas containing a silicon element, and the reactant gas may be a gas containing either or both of an oxygen element and a nitrogen element and not containing a silicon element.

The precursor gas may be a gas containing an aminosilane-based gas, a silicon alkoxide-based gas or a halogen element as well as a silicon element.

Each of the first sensor and the second sensor may be a pressure gauge. A pressure within the chamber may be controlled based on the measurement value of the first sensor in the third process, and the pressure within the chamber may be controlled based on the measurement value of the second sensor in the sixth process.

Each of the first sensor and the second sensor may be a capacitance manometer.

A processing apparatus includes a chamber configured to accommodate a processing target object therein; a first sensor; a second sensor; a first blocking unit configured to expose or block the first sensor to or from a processing space within the chamber; a second blocking unit configured to expose or block the second sensor to or from the processing space within the chamber; a first supply unit configured to supply a first processing gas containing a precursor gas into the chamber; a second supply unit configured to supply a second processing gas containing a reactant gas into the chamber; and a control device configured to control a processing performed on the processing target object. The control device repeatedly performs multiple times the processing including a first process of exposing the first sensor to the processing space within the chamber by controlling the first blocking unit and blocking the second sensor from the processing space within the chamber by controlling the second blocking unit; a second process of supplying the first processing gas into the chamber by controlling the first supply unit; a third process of controlling a state within the chamber based on a measurement value of the first sensor; a fourth process of blocking the first sensor from the processing space within the chamber by controlling the first blocking unit and exposing the second sensor to the processing space within the chamber by controlling the second blocking unit; a fifth process of supplying the second processing gas into the chamber by controlling the second supply unit; and a sixth process of controlling the state within the chamber based on a measurement value of the second sensor.

According to the exemplary embodiments, the deterioration of the accuracy of the processing upon the processing target substrate can be suppressed.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of a processing method and a processing apparatus of the present disclosure will be described in detail with reference to the accompanying drawings. However, it should be noted that the processing method and the processing apparatus of the present disclosure are not limited to the exemplary embodiments.

First Exemplary Embodiment

<Configuration of Processing Apparatus10>

FIG. 1is a diagram illustrating an example of a processing apparatus10according to a first exemplary embodiment. As shown inFIG. 1, for example, the processing apparatus10according to the present exemplary embodiment includes a chamber21which is made of, e.g., aluminum having an anodically oxidized surface and has a substantially cylindrical processing space formed therein. The chamber21is frame-grounded. The processing apparatus10according to the present exemplary embodiment is configured as, for example, a capacitively coupled parallel plate type plasma processing apparatus. A supporting table23is placed within the chamber21with an insulating plate22made of ceramic or the like therebetween. Provided on the supporting table23is a susceptor24which is made of, by way of non-limiting example, aluminum and serves as a lower electrode.

An electrostatic chuck25configured to attract and hold a semiconductor wafer W as an example of a processing target object by an electrostatic force is provided at a substantially central portion of a top surface of the susceptor24. The electrostatic chuck25has a structure in which an electrode26made of a conductive film or the like is embedded between a pair of insulating layers. The electrode26is electrically connected with a DC power supply27. Further, the electrostatic chuck25may be provided with a non-illustrated heater configured to heat the semiconductor wafer W.

A focus ring25ais provided on the top surface of the susceptor24to surround the electrostatic chuck25. The focus ring25acan improve plasma uniformity in the vicinity of an edge of the semiconductor wafer W. The focus ring25ais made of, by way of example, but not limitation, single crystalline silicon or the like. An inner wall member28is provided on side surfaces of the supporting table23and the susceptor24to surround the supporting table23and the susceptor24. The inner wall member28is made of, by way of non-limiting example, quartz and has a substantially cylindrical shape.

A coolant path29is formed within the supporting table23along a circumferential direction of the supporting table23, for example. A coolant of a preset temperature from a non-illustrated external chiller unit is supplied into and circulated in the coolant path29through a pipeline30aand a pipeline30b. By circulating the coolant of the preset temperature within the coolant path29, the semiconductor wafer W on the electrostatic chuck25can be controlled to a predetermined temperature through a heat exchange with the coolant. Furthermore, a heat transfer gas supplied from a non-illustrated gas supply mechanism is supplied through a pipeline31into a gap between a top surface of the electrostatic chuck25and a rear surface of the semiconductor wafer W on the electrostatic chuck25. The heat transfer gas may be, for example, a helium gas.

An upper electrode40is provided above the susceptor24serving as the lower electrode to face the susceptor24with the processing space within the chamber21therebetween. A space between the upper electrode40and the susceptor24surrounded by the chamber21is the processing space in which plasma is generated. The upper electrode40is equipped with a ceiling plate42serving as an electrode main body; and a ceiling plate supporting member41configured to support the ceiling plate42.

The ceiling plate supporting member41is supported at an upper portion of the chamber21with an insulating member45therebetween. The ceiling plate supporting member41is made of a conductive material having relatively high thermal conductivity such as, but not limited to, aluminum having an anodically oxidized surface and has a substantially circular plate shape. Further, the ceiling plate supporting member41also serves as a cooling plate configured to cool the ceiling plate42heated by the plasma generated in the processing space. The ceiling plate supporting member41is provided with a gas inlet opening46through which a processing gas is supplied; a diffusion space43in which the processing gas introduced from the gas inlet opening46is diffused; and a multiple number of flow openings43aas passages through which the processing gas diffused in the diffusion space43is flown downwards.

The ceiling plate42is made of a silicon-containing material such as, but not limited to, quartz and has a substantially circular plate shape. Multiple gas inlet openings42aare formed through the ceiling plate42in a thickness direction thereof. The gas inlet openings42aare arranged to respectively communicate with the corresponding flow openings43aof the ceiling plate supporting member41. With this configuration, the processing gas supplied into the diffusion space43is diffused and supplied into the chamber21in a shower shape through the flow openings43aand the gas inlet openings42a.

The gas inlet opening46of the ceiling plate supporting member41is connected with a plurality of valves50ato50cvia a pipeline47. The valve50ais connected to a gas supply source48avia a mass flow controller (MFC)49a. If the valve50ais controlled to be an open state, a processing gas supplied from the gas supply source48ais supplied into the chamber21through the pipeline47while its flow rate is controlled by the MFC49a. In the present exemplary embodiment, the gas supply source48asupplies a precursor gas into the chamber21. The MFC49aand the valve50aare an example of a first supply unit.

In the present exemplary embodiment, a gas containing, for example, a silicon element and not containing an oxygen element is used as the precursor gas. By way of example, a gas containing an organic silicon compound or a gas containing an inorganic silicon compound may be used as the precursor gas.

The gas containing the organic silicon compound may be, by way of non-limiting example, an aminosilane-based gas having a valence of 1 to 3. The aminosilane-based gas having a valence of 1 to 3 may be one or more gases selected from BTBAS (bistertiarybutylaminosilane), BDMAS (bisdimethylaminosilane), BDEAS (bisdiethylaminosilane), DMAS (dimethylaminosilane), DEAS (diethylaminosilane), DPAS (dipropylaminosilane), BAS (butylaminosilane), DIPAS (diisopropylaminosilane), BEMAS (bisethylmethylaminosilane) and TDMAS (tridimethylaminosilane). Alternatively, the gas containing the organic silicon compound may be a siliconalkoxide-based gas such as, but not limited to, TEOS (tetraethoxysilane).

As the gas containing the inorganic silicon compound, one or more kinds of gases selected from, by way of non-limiting example, a SiCl4gas, a SiF4gas, a Si2Cl6gas and a SiH2Cl2gas may be used. Further, one or more kinds of gases selected from a group including the gas containing the organic silicon compound and the gas containing the inorganic silicon compound may be used as the precursor gas, for example.

Furthermore, the valve50bis connected to a gas supply source48bvia a MFC49b. If the valve50bis controlled to be an open state, a gas supplied from the gas supply source48bis supplied into the chamber21through the pipeline47while its flow rate is controlled by the MFC49b. In the present exemplary embodiment, the gas supply source48bsupplies a purge gas into the chamber21. The purge gas may be, by way of example, but not limitation, an inert gas such as an argon gas or a nitrogen gas.

Further, the valve50cis connected to a gas supply source48cvia a MFC49c. If the valve50cis controlled to be in an open state, a gas supplied from the gas supply source48cis supplied into the chamber21through the pipeline47while its flow rate is controlled by the MFC49c. In the present exemplary embodiment, the gas supply source48csupplies a reactant gas into the chamber21. The MFC49cand the valve50care an example of a second supply unit.

For example, in the present exemplary embodiment, a gas containing either or both of an oxygen element and a nitrogen element and not containing a silicon element is used as the reactant gas. To elaborate, one or more kinds of gases selected from an O2gas, a CO gas, a CO2gas, an O3gas, a H2O gas, a NO gas, a N2O gas, a N2gas and a NH3gas may be used as the reactant gas.

Moreover, in supplying the precursor gas and the reactant gas of the present exemplary embodiment into the chamber21, an additive gas may be used for the purposes of improving productivity such as reduction of using amounts of the precursor gas and the reactant gas and uniformity of gas distribution within the chamber21. The additive gas may be, by way of example, but not limitation, an inert gas such as an argon gas or a nitrogen gas. For example, the inert gas supplied from the gas supply source48bthrough the valve50band the MFC49bmay be added to the precursor gas which is supplied from the gas supply source48athrough the valve50aand the MFC49a. Furthermore, by way of another example, the inert gas supplied from the gas supply source48bthrough the valve50band the MFC49bmay be added to the reactant gas which is supplied from the gas supply source48cthrough the valve50cand the MFC49c.

Control over flow rates of the individual gases by the individual MFCs49ato49cand opening/closing of the individual valves50ato50care performed by a control device60to be described later.

A variable DC power supply52is electrically connected to the upper electrode40via a cable51aand a low pass filter (LPF)51. On/off of a DC voltage supplied to the upper electrode40from the variable DC power supply52via the LPF51and the cable51ais controlled by a switch53. Control over the voltage of the variable DC power supply52and the on/off of the switch53are performed by the control device60to be described later.

The susceptor24serving as the lower electrode is electrically connected with a high frequency power supply34avia a matching device33a. Further, the susceptor24is also connected with a high frequency power supply34bvia a matching device33b. The high frequency power supply34ais configured to supply a high frequency power of a first frequency equal to or higher than 27 MHz, e.g., 40 MHz to the susceptor24via the matching device33a. The high frequency power supply34bis configured to supply a high frequency power of a second frequency equal to or lower than 13.56 MHz, e.g., 2 MHz to the susceptor24via the matching device33b. As the high frequency power of the first frequency is supplied to the susceptor24, plasma of the processing gas is generated in the processing space. Further, as the high frequency power of the second frequency is supplied to the susceptor24, active species such as ions in the plasma are attracted into the semiconductor wafer W on the electrostatic chuck25. The high frequency powers supplied from the high frequency power supplies34aand34bare controlled by the control device60to be described later.

An opening78is formed at a sidewall of the chamber21, and a pipeline38is connected to the opening78. The pipeline38is branched into two, and one end of a valve37ais connected to one branch and one end of a valve37bis connected to the other branch. The other end of the valve37ais connected to a pressure gauge36avia a pipeline38a, and the other end of the valve37bis connected to a pressure gauge36bvia a pipeline38b. In the present exemplary embodiment, the pressure gauges36aand36bmay be implemented by, but not limited to, capacitance manometers. Further, in the following description, the valve37amay sometimes be referred to as a valve A, and the valve37bmay sometimes be referred to as a valve B.

As the valve37ais controlled to be in an open state, the pipeline38and the pipeline38aare allowed to communicate with each other. Accordingly, the pressure gauge36ais exposed to the processing space within the chamber21through the opening78formed at the sidewall of the chamber21, and, thus, the pressure gauge36ais capable of measuring a pressure within the processing space. Meanwhile, as the valve37ais controlled to be in a closed state, the pipeline38and the pipeline38aare disconnected from each other. Accordingly, the pressure gauge36ais blocked from the processing space within the chamber21.

Further, as the valve37bis controlled to be in an open state, the pipeline38and the pipeline38bare allowed to communicate with each other. Accordingly, the pressure gauge36bis exposed to the processing space within the chamber21through the opening78formed at the sidewall of the chamber21, and, thus, the pressure gauge36bis capable of measuring a pressure within the processing space. Meanwhile, as the valve37bis controlled to be in a closed state, the pipeline38and the pipeline38bare disconnected from each other. Accordingly, the pressure gauge36bis blocked from the processing space within the chamber21.

The control over the opening/closing of the valves37aand37bare performed by the control device60to be described later. The valve37ais an example of a first blocking unit, and the valve37bis an example of a second blocking unit. Further, the pressure gauge36ais an example of a first sensor, and the pressure gauge36bis an example of a second sensor.

An exhaust port71is provided at a bottom portion of the chamber21, and an exhaust device73is connected to the exhaust port via an exhaust line72. The exhaust device73includes a vacuum pump such as, but not limited to, a DP (Dry Pump) or a TMP (Turbo Molecular Pump), and is configured to decompress the inside of the chamber21to a required vacuum level. An exhaust rate of the exhaust device73or the like is controlled by the control device60to be described later. By way of example, when the precursor gas is supplied into the chamber21from the gas supply source48a, the control device60controls the valve37ato be opened while controlling the valve37bto be closed. Then, the control device60adjusts the pressure within the chamber21to a preset pressure by controlling the exhaust rate of the exhaust device73or the like based on the pressure within the chamber21measured by the pressure gauge36a. Further, for example, when the reactant gas is supplied into the chamber21from the gas supply source48c, the control device60controls the valve37ato be closed while controlling the valve37bto be opened. Then, the control device60adjusts the pressure within the chamber21to a predetermined pressure by controlling the exhaust rate of the exhaust device73or the like based on the pressure within the chamber21measured by the pressure gauge36b.

The sidewall of the chamber21is also provided with an opening74through which a carry-in/out of the semiconductor wafer W is performed. The opening74is opened/closed by a gate valve G. Further, a deposition shield76is provided at an inner wall of the chamber21in a detachable manner along an inner wall surface thereof. In addition, a deposition shield77is detachably provided on an outer surface of the inner wall member28as well. The deposition shields76and77are configured to suppress an etching byproduct (deposit) from adhering to the inner wall of the chamber21and the inner wall member28. Further, a conductive member (GND block)79, which is connected to the ground, is provided at a position of the deposition shield76which is substantially on a level with the semiconductor wafer W placed on the electrostatic chuck25. The GND block79is configured to suppress an abnormal discharge within the chamber21.

An overall operation of the above-described processing apparatus10is controlled by the control device60. The control device60includes a memory61such as, but not limited to, a ROM (Read Only Memory) or a RAM (Random Access Memory); processor62such as, but not limited to, a CPU (Central Processing Unit) or a DSP (Digital Signal Processor); and a user interface63. The user interface63includes a keyboard through which a user such as a process manager inputs commands to manage the processing apparatus10; a display configured to visually display an operational status of the processing apparatus10; and so forth.

The memory61stores therein a control program (software) or a recipe including processing condition data for implementing various kinds of processings in the processing apparatus10. The processor62reads out a required recipe from the memory61in response to an instruction from the user through the user interface63and executes the corresponding recipe, thus controlling the individual components of the processing apparatus10. Accordingly, a required processing such as a film forming processing is performed by the processing apparatus10. Further, the control program or the recipe including the processing condition data may be used by being stored in a computer-readable recording medium or may be transmitted from another apparatus through, for example, a communication line. Here, the computer-readable recording medium may be, by way of non-limiting example, a hard disk, a CD (Compact disc), a DVD (Digital Versatile Disc), a flexible disk, a semiconductor memory, or the like.

Here, the film forming processing performed by the processing apparatus10according to the present exemplary embodiment will be explained. The processing apparatus10according to the present exemplary embodiment is configured to form a silicon oxide film on the semiconductor wafer W by PEALD (Plasma-Enhanced ALD).FIG. 2is a schematic diagram illustrating an example of individual processes of the PEALD. In the PEALD, the precursor gas is first supplied to the semiconductor wafer W in an adsorption process. Accordingly, molecules of the precursor gas are adsorbed onto the surface of the semiconductor wafer W.

To elaborate, as depicted on the left side ofFIG. 3, for example, if molecules of, e.g., the aminosilane-based gas contained in the precursor gas are supplied to the semiconductor wafer W, among silyl groups and the amine groups constituting the molecules of the aminosilane-based gas, the amine groups make a substitution reaction with OH groups existing on the surface of the semiconductor wafer W. Further, the silyl groups combine with oxygen elements in the OH groups on the semiconductor wafer W to be chemically adsorbed to the surface of the semiconductor wafer W. Further, since an end of each silyl group is terminated with a hydrogen element, no more substitution reaction occurs between the silyl group and other molecules of the aminosilane-based gas. That is, in the adsorption process, the surface of the semiconductor wafer W is terminated with a single molecular layer of the silyl groups.

Thereafter, in a first purging process shown inFIG. 2, for example, a purge gas is supplied onto the semiconductor wafer W. Accordingly, the molecules of the precursor gas excessively supplied onto the semiconductor wafer W and so forth are removed by the purge gas. To be more specific, as depicted on the right side ofFIG. 3, for example, reaction byproducts such as amine compounds generated by the amine groups released through the substitution reaction or the molecules of the precursor gas excessively supplied onto the semiconductor wafer W is removed by the purge gas.

Subsequently, in a reaction process shown inFIG. 2, active species are supplied to the semiconductor wafer W. Accordingly, the molecules of the precursor gas adsorbed onto the semiconductor wafer W react with the active species, so that a silicon oxide film is formed. In the present exemplary embodiment, as depicted on the left side ofFIG. 4, for example, by exciting the reactant gas into plasma, oxygen radicals (O*) are generated as the active species. As the generated active species react with the silyl groups adsorbed to the surface of the semiconductor wafer W, the silicon oxide film is formed on the semiconductor wafer W, as illustrated on the right side ofFIG. 4, for example. Further, OH groups are formed again on a surface of the formed silicon oxide film.

Next, in a second purging process shown inFIG. 2, for example, the purge gas is supplied onto the semiconductor wafer W. Accordingly, the active species excessively supplied onto the semiconductor wafer W, reaction byproducts such as water molecules generated by the reaction between the active species and the silyl groups on the surface of the semiconductor wafer W, and so forth are removed by the purge gas. For example, as depicted on the right side ofFIG. 4, since the OH groups are formed on the surface of the silicon oxide film again, a single layer of silyl groups can be formed again by supplying the precursor gas onto the semiconductor wafer W again in an absorption process.

As stated above, a cycle including the adsorption process, the first purging process, the reaction process and the second purging process is repeated multiple times, a preset thickness of the silicon oxide film is formed on the semiconductor wafer W.

Here, though the required film is deposited on the semiconductor wafer W as the cycle of the PEALD is repeated, this film is also deposited on a component within the chamber21having OH groups on the surface thereof as a deposit. For example, a pressure gauge may be provided within the chamber21to measure the pressure of the gas supplied in each process of the PEALD, and the pressure within the chamber21may be measured by the single pressure gauge in all of the individual processes of the PEALD. In this case, the silicon oxide film may be deposited on a sensor surface of this pressure gauge as the deposit, the same as the silicon oxide film is deposited on the semiconductor wafer W.

If the deposit adheres to the sensor surface of the pressure gauge, an error of a measurement value of the pressure gauge increases. Therefore, a measurement error of the pressure gauge needs to be adjusted during the processes of the PEALD.FIG. 5is a diagram showing an example of an accumulated value of an adjustment amount of the pressure gauge. InFIG. 5, a horizontal axis represents an accumulated application time of the high frequency power supplied to generate plasma of the reaction gas, and a vertical axis indicates an accumulated value of the adjustment amount. If an accumulated processing time of the PEALD is lengthened, that is, the accumulated application time of the high frequency power is lengthened, a thickness of the deposit adhering to the sensor surface of the pressure gauge is increased. Therefore, as shown inFIG. 5, for example, with the increase of the accumulated application time of the high frequency power, the accumulated value of the adjustment amount of the measurement error is also increased. If the accumulated value of the adjustment amount of the measurement error is increased, the measurement error may be soon increased beyond a tolerance range, so that the accuracy of the pressure adjustment within the chamber21is deteriorated.

To avoid this problem, in the processing apparatus10according to the present exemplary embodiment, a pressure gauge exposed to the inside of the chamber21when supplying the precursor gas into the chamber21and a pressure gauge exposed to the inside of the chamber21when supplying the reactant gas into the chamber21are provided separately. Accordingly, it is possible to suppress at least both of the adsorption process and the reaction process among the four processes shown inFIG. 2from being performed on the sensor surface of each of these pressure gauges.

For example, in the adsorption process shown inFIG. 2, if all the OH groups existing on the semiconductor wafer W are terminated with the silyl groups of the molecules of the precursor gas, the ends of the silyl groups are terminated with hydrogen atoms and do not have OH groups. As a result, the molecules of the precursor gas are not adsorbed to the semiconductor wafer W any more. Thus, in case that the adsorption process and the first purging process are repeated alternately, the thickness of the deposit adhering to the sensor surface of the pressure gauge is not increased.

Further, in the reaction process shown inFIG. 2, for example, if the silyl groups of the molecules of the precursor gas do not exist on the semiconductor wafer W, the silicon oxide film is not formed on the semiconductor wafer W. Therefore, even if only the reaction process is repeated multiple times, the deposit hardly adheres to the sensor surface of the pressure gauge.

As stated above, by providing the pressure gauge exposed to the inside of the chamber21when supplying the precursor gas into the chamber21and the pressure gauge exposed to the inside of the chamber21when supplying the reactant gas into the chamber21separately, the increase of the thickness of the deposit adhering to each pressure gauge can be suppressed. Accordingly, the increase of the measurement error of each pressure gauge can be suppressed within a preset range and the deterioration of the accuracy of each pressure gauge can be suppressed within a preset range. Therefore, the deterioration of processing accuracy of the processing apparatus10according to the present exemplary embodiment can be suppressed.

Furthermore, since the increase of the thickness of the deposit adhering to each pressure gauge can be suppressed, the adjustment frequency of the measurement error of each pressure gauge can be reduced. Hence, the processing throughput can be improved.

In addition, as illustrated inFIG. 2, for example, if the adsorption process is performed, the molecules of the precursor gas float within the chamber21until the first purging process is conducted. Thus, if a pressure measurement in the first purging process and a pressure measurement in the reaction process are performed by a single pressure gauge, the deposit adhering to the sensor surface of the pressure gauge may be increased. Further, if the reaction process is performed, the active species float within the chamber21until the second purging process is performed. Thus, if a pressure measurement in the second purging process and a pressure measurement in an adsorption process of a next cycle are performed by a single pressure gauge, the deposit adhering to the sensor surface of the pressure gauge may be increased. Therefore, it is desirable that the pressure measurement in the adsorption process and the first purging process and the pressure measurement in the reaction process and the second purging process are performed by using the individual pressure gauges.

Further, though the present exemplary embodiment has been described for the case where the active species are generated by exciting the reactant gas into the plasma, if the semiconductor wafer W or the component exposed to the inside of the chamber21is maintained at a high temperature, the active species may be generated from the reactant gas by heat energy from the corresponding high temperature. For this reason, it is desirable that the precursor gas and the reactant gas are not supplied into the chamber21at the same time and, also, the residue of the precursor gas and the reactant gas are not mixed with each other.

FIG. 6is a flowchart for describing an example of a sequence of a processing according to the first exemplary embodiment. The processing shown inFIG. 6is performed mainly by the control device60.

First, a semiconductor wafer W is carried into the chamber21and placed on the electrostatic chuck25, and the gate valve G is closed. The control device60controls the electrostatic chuck25such that the semiconductor wafer W is attracted to and held on the top surface of the electrostatic chuck25by the electrostatic force. Then, the control device60starts the vacuum evacuation of the chamber21by controlling the exhaust device73(S100). Next, the control device60controls the valve37a(valve A) and the valve37b(valve B) to be opened (S101).

Thereafter, the control device60prepares for the adsorption process or the reaction process according to the recipe read out from the memory61(S102). The preparation for the adsorption process and the reaction process includes, for example, a processing of adjusting the temperature of the semiconductor wafer W by performing the temperature adjustment of the coolant supplied into and circulated in the coolant path29of the supporting table23, the temperature adjustment of the heater within the electrostatic chuck25and the pressure adjustment of the heat transfer gas supplied between the electrostatic chuck25and the semiconductor wafer W.

Afterwards, the control device60determines, by referring to the recipe, whether the gas supplied into the chamber21is the precursor gas (S103). If the gas supplied into the chamber21is the precursor gas (S103: Yes), the control device60controls the valve A to be still opened while controlling the valve B to be closed (S104). Accordingly, the pressure gauge36ais exposed to the processing space within the chamber21, whereas the pressure gauge36bis blocked from the processing space within the chamber21. The process S104is an example of a first process.

Then, the control device60performs the adsorption process according to the recipe (S105). In the adsorption process, the control device60controls the valve50ato be opened and the valves50band50cto be closed, for example, and, also, adjusts the flow rate of the precursor gas supplied into the chamber21from the gas supply source48aby controlling the MFC49a. Accordingly, the precursor gas is supplied into the chamber21. The process of supplying the precursor gas into the chamber21is an example of a second process. Further, the control device60adjusts the pressure within the chamber21by controlling the exhaust rate of the exhaust device73based on, for example, the pressure within the chamber21measured by the pressure gauge36a. Accordingly, the molecules of the precursor gas are adsorbed onto the semiconductor wafer W under a preset condition. The process of adjusting the pressure of the precursor gas supplied into the chamber21is an example of a third process.

Next, the control device60performs the first purging process (S106). In the first purging process, the control device60controls the valves50aand50cto be closed while controlling the valve50bto be in an open state and, also, controls the flow rate of the purge gas supplied into the chamber21from the gas supply source48bby controlling the MFC49b. Furthermore, the control device60adjusts the pressure within the chamber21by controlling the exhaust rate of the exhaust device73based on the pressure within the chamber21measured by, for example, the pressure gauge36a. Accordingly, the purge gas is supplied onto the semiconductor wafer W under a preset condition, so that the molecules of the precursor gas excessively supplied, the reaction byproduct, and so forth are removed. Then, the control device60performs a processing of a process S110.

Meanwhile, in case that the gas supplied into the chamber21is not the precursor gas (S103: No), that is, in case that the gas supplied into the chamber21is the reactant gas, the control device60controls the valve A to be closed while controlling the valve B to be opened (S107). Accordingly, the pressure gauge36ais blocked from the processing space within the chamber21, and the pressure gauge36bis exposed to the processing space within the chamber21. The process S107is an example of a fourth process.

Then, the control device60performs the reaction process according to the recipe (S108). For example, in the reaction process, the control device60controls the valves50aand50bto be closed and the valve50cto be opened and, also, controls the flow rate of the reactant gas supplied into the chamber21from the gas supply source48cby controlling the MFC49c. Accordingly, the reactant gas is supplied into the chamber21. The process of supplying the reactant gas into the chamber21is an example of a fifth process. Further, the control device60adjusts the pressure within the chamber21by controlling the exhaust rate of the exhaust device73based on the pressure within the chamber21measured by, for example, the pressure gauge36b. The process of adjusting the pressure of the reactant gas supplied into the chamber21is an example of a sixth process. Further, the control device60controls the high frequency power supplies34aand34bto apply the high frequency powers to the susceptor24, so that the plasma of the reactant gas is generated in the processing space within the chamber21. As a result, the active species such as oxygen radicals are supplied onto the semiconductor wafer W under a preset condition, so that the silicon oxide film is formed on the semiconductor wafer W. The process of generating the plasma of the reactant gas in the processing space within the chamber21is an example of a seventh process.

Subsequently, the control device60performs the second purging process (S109). In the second purging process, the control device60controls the valves50aand50cto be closed while controlling the valve50bto be opened and, also, controls the flow rate of the purge gas supplied into the chamber21from the gas supply source48bby controlling the MFC49b. Furthermore, the control device60adjusts the pressure within the chamber21by controlling the exhaust rate of the exhaust device73based on the pressure within the chamber21measured by, for example, the pressure gauge36b. Accordingly, the purge gas is supplied onto the semiconductor wafer W under a preset condition, so that unreacted active species, the reaction byproduct, or the like within the chamber21is removed.

Thereafter, referring to the recipe, the control device60determines whether there remains a next process (S110). If there still exists a next process (S110: Yes), the control device60performs the processing of the process S102again.

Meanwhile, if there remains no next process (S110: No), the control device60starts the vacuum evacuation of the chamber21again (S111). To elaborate, the control device60controls the valves50ato50cto be closed and controls the exhaust device73to exhaust the gas remaining in the chamber21.

Then, the control device60determines whether the valve A is in an open state (S112). In case that the valve A is in the open state (S112: Yes), the residual gas within the valve A and the pipeline38ais already exhausted by the vacuum evacuation which is begun in the process S111. Therefore, the control device60controls the valve A to be closed and the valve B to be opened (S113). As a result, the residual gas in the valve B and the pipeline38bis exhausted by the vacuum evacuation which is begun in the process S111. Then, the control device60controls the valve A to be opened (S114) and ends the processing shown inFIG. 6.

Meanwhile, If the valve A is not in the open state (S112: No), that is, if the valve B is in an open state, the residual gas within the valve B and the pipeline38bis already exhausted by the vacuum evacuation which is begun in the process s111. Therefore, the control device60controls the valve B to be closed and the valve A to be opened (S115). As a result, the residual gas in the valve A and the pipeline38ais exhausted by the vacuum evacuation which is begun in the process S111. Then, the control device60controls the valve B to be opened (S116) and ends the processing shown inFIG. 6.

In the above, the first exemplary embodiment has been described. As clearly seen from the above description, the processing apparatus10according to the present exemplary embodiment controls the valve A and the valve B such that the different pressure gauges are exposed to the inside of the chamber21when supplying the precursor gas into the chamber21and when supplying the reactant gas into the chamber21in each cycle of the PEALD. Accordingly, the increase of the thickness of the deposit adhering to each pressure gauge can be suppressed, so that the reduction of the accuracy of each pressure gauge can be suppressed within a preset range. Thus, the processing apparatus10according to the present exemplary embodiment is capable of suppressing the deterioration of the accuracy of the processing.

Second Exemplary Embodiment

The processing apparatus10according to the above-described first exemplary embodiment is configured to perform the film formation on the semiconductor wafer W by the PEALD. Meanwhile, the processing apparatus10according to a second exemplary embodiment is configured to perform, within the single chamber21, the film formation on the semiconductor wafer W by the PEALD and then to perform an etching processing subsequently on the semiconductor wafer W on which the film formation is already performed.

<Configuration of Processing Apparatus10>

FIG. 7is a diagram illustrating an example of the processing apparatus10according to the second exemplary embodiment. Since parts assigned the same reference numerals as those ofFIG. 1have the same configuration or function as shown inFIG. 1except the following, redundant description will be omitted.

In the plasma processing apparatus10according to the present exemplary embodiment, a plurality of valves50ato50dis connected to the pipeline47. The valve50dis connected to a gas supply source48dvia a mass flow controller (MFC)49d. If the valve50dis controlled to be an open state, a gas supplied from the gas supply source48dis supplied into the chamber21through the pipeline47while its flow rate is controlled by the MFC49d. In the present exemplary embodiment, the gas supply source48dis configured to supply an etching gas into the chamber21. As an example of the etching gas, a CF-based gas or a CF-based gas with an oxygen gas or a hydrogen gas added thereto may be used. Adjustment of the flow rate of the etching gas by the MFC49dand opening/closing of the valve50dare controlled by the control device60.

In the present exemplary embodiment, the control device60forms a film having a preset thickness on the semiconductor wafer W by repeating the cycle of the PEALD shown inFIG. 2a preset number of times. Subsequently, the control device60adjusts the pressure within the chamber21to a predetermined pressure by supplying the etching gas into the chamber21. At this time, the control device60controls the valve A to be closed and the valve B to be opened. The control device60adjusts the pressure within the chamber21based on the pressure measurement value measured by the pressure gauge36bexposed to the processing space within the chamber21.

Here, in the processing apparatus10according to the present exemplary embodiment, the valve A and the valve B are controlled such that the pressure gauge exposed to the inside of the chamber21when supplying the precursor gas into the chamber21and the pressure gauge exposed to the inside of the chamber21when supplying the reactant gas into the chamber21in each cycle of the PEALD are different. Accordingly, the deposit adhering to each pressure gauge can be suppressed. Thus, even when the etching processing is performed in the same chamber following the film formation such as the PEALD or the like, the pressure gauges used in the film formation can be still used.

When the etching processing is performed, since the etching gas is excited into plasma, active species such as oxygen radicals (O*) are generated. Therefore, in each cycle of the PEALD, if the pressure gauge exposed to the inside of the chamber21when supplying the precursor gas into the chamber21is used when the etching processing is performed, a silicon oxide film may be deposited on the sensor surface of the corresponding pressure gauge as the deposit. Further, the pressure within the chamber21set in the etching processing is lower than the pressure within the chamber21set in the film formation such as the PEALD. Accordingly, the accuracy of the pressure adjustment within the chamber21in the etching processing may be easily affected by the error of the pressure gauge. In the processing apparatus10according to the present exemplary embodiment, however, since the deposit that might be attached to the pressure gauge can be suppressed, it is possible to suppress the deterioration in the accuracy of the pressure adjustment within the chamber21in the etching processing.

Furthermore, as described inFIG. 2, for example, the substitution reaction takes place between the molecules of the precursor gas and the OH groups on the surface of the component within the chamber21in the adsorption process. Accordingly, a single layer of silyl groups of the molecules of the precursor gas is deposited on the sensor surface of the pressure gauge36aused to measure the pressure within the chamber21in the adsorption process. On the contrary, in the reaction process, if no silyl group exists on the surface of the component within the chamber21, the deposit is not formed on the surface of the component within the chamber21in principle. In the etching processing, since the pressure gauge is required to have higher accuracy than in the film formation, the pressure gauge36bused in the reaction process, not the pressure gauge36aused in the adsorption process, is used to measure the pressure within the chamber21in the etching processing. Thus, the accuracy of the pressure adjustment within the chamber21in the etching processing can be further improved.

FIG. 8is a flowchart for describing an example of a sequence of a processing according to the second exemplary embodiment. The processing shown inFIG. 8is performed mainly by the control device60. Further, since processes assigned the same reference numerals as those ofFIG. 6are the same as corresponding processes described inFIG. 6except the following, redundant description will be omitted.

First, the control device60forms the film of the preset thickness on the semiconductor wafer W by performing the processings of the processes S100to S111shown inFIG. 6. Then, the control device60determines whether the valve A is in an open state (S112). If the valve A is in the open state (S112: Yes), the control device60controls the valve A to be closed and the valve B to be opened (S113). Accordingly, the residual gas in the valve B and the pipeline38bis exhausted by the vacuum evacuation which is started in the process S111. Then, the control device60performs a processing of a process S120. Through the processing of the process S113, the pressure gauge36ais blocked from the processing space within the chamber21, whereas the pressure gauge36bis exposed to the processing space within the chamber21. The process S113is an example of an eighth process.

Meanwhile, if the valve A is not in the open state (S112: No), that is, if the valve B is in an open state, the control device60controls the valve B to be closed and the valve A to be opened (S115). Accordingly, the residual gas in the valve A and the pipeline38ais exhausted by the vacuum evacuation which is started in the process S111. Then, the control device60performs the processing of the process S113.

Thereafter, the control device60prepares for the etching process by referring to the recipe (S120). The preparation for the etching process includes, for example, a processing of adjusting the temperature of the semiconductor wafer W by performing the temperature adjustment of the coolant supplied into and circulated in the coolant path29of the supporting table23, the temperature adjustment of the heater within the electrostatic chuck25and the pressure adjustment of the heat transfer gas supplied between the electrostatic chuck25and the semiconductor wafer W.

Subsequently, the control device60performs the etching process (S121). In the etching process, the control device60controls valves50ato50cto be closed and the valve50dto be opened, for example, and, also, controls the flow rate of the etching gas supplied into the chamber21from the gas supply source48dby controlling the MFC49d. Accordingly, the etching gas is supplied into the chamber21. The process of supplying the etching gas into the chamber21is an example of a ninth process. Further, the control device60adjusts the pressure within the chamber21by controlling the exhaust rate of the exhaust device73based on, for example, the pressure within the chamber21measured by the pressure gauge36b. The process of adjusting the pressure of the etching gas within the chamber21is an example of a tenth process. Further, the control device60controls the high frequency power supplies34aand34bto apply the high frequency powers to the susceptor24, so that the plasma of the etching gas is generated in the processing space within the chamber21. Accordingly, the silicon oxide film on the semiconductor wafer W is etched under a preset condition. The process of generating the plasma of the etching gas in the processing space within the chamber21is an example of an eleventh process.

Then, the control device60resumes the vacuum evacuation of the chamber21(S122). To elaborate, the control device60controls the valves50ato50dto be closed and exhausts the gas remaining in the chamber21by controlling the exhaust device73. Then, the control device60controls the valve A to be opened (S123) and ends the processing ofFIG. 8.

In the above, the second exemplary embodiment has been described. As clearly seen from the above description, in the processing apparatus10according to the present exemplary embodiment, the pressure within the chamber21is adjusted in the etching process, which is performed in the same chamber21following the film forming processing, by using the pressure gauge36bwhich is used in the reaction process of the PEALD. Thus, it is possible to suppress the deterioration of the accuracy of the pressure adjustment in the etching processing. Hence, the processing apparatus10according to the present exemplary embodiment is capable of suppressing the deterioration of the accuracy of the processing.

In the reaction process in each cycle of the ALD in the above-described exemplary embodiments, the active species are generated by exciting the reactant gas into the plasma. However, the present disclosure is not limited thereto, and the active species may be generated by various other methods such as heat.

Further, in the above-described exemplary embodiments, the inert gas such as the nitrogen gas is supplied into the chamber21in the first and second purging processes in each cycle of the ALD. However, the present disclosure is not limited thereto. In the first and second purging processes in each cycle of the ALD, the purging may be performed just by stopping the supply of the gas and vacuum-evacuating the chamber21.

Furthermore, in the above-described exemplary embodiments, the pressure gauges36aand36bare used as the sensors configured to measure the internal state of the chamber21. However, the present disclosure may not be limited thereto and may also be applicable to any of various sensors such as an EPD (End Point Detector), a quadrupole mass (Q-mass) spectrometer and a sidewall potential monitor as long as at least a part of a sensor surface of the sensor is exposed to the processing space within the chamber21and the sensor is configured to measure the internal state of the chamber21.

Moreover, in the above-described exemplary embodiments, the pressure gauge is implemented by the capacitance manometer. However, the present disclosure is not limited thereto. That is, another type of pressure gauge such as a pirani gauge may be used as long as at least a part of a sensor surface of the pressure gauge is exposed to the processing space within the chamber21and the pressure gauge is configured to measure the pressure within the chamber21.

Further, the above exemplary embodiments have been described for the example where the film formed on the semiconductor wafer W by the ALD is the silicon oxide film. However, the present disclosure is not limited thereto, and another film such as a silicon nitride film may be formed on the semiconductor wafer W by the ALD.

In addition, in the above-described exemplary embodiments, the processing apparatus10uses capacitively coupled plasma (CCP) as the plasma source. However, the present disclosure is not limited thereto, and the plasma processing apparatus10may use any of various types of plasma sources such as inductively coupled plasma (ICP) and microwave plasma.