PLASMA PROCESSING DEVICE AND PLASMA PROCESSING METHOD

There is provided a plasma processing device comprising: a chamber; an upper electrode; a showerhead provided below the upper electrode, which divides an internal space of the chamber into a first space between the upper electrode and the showerhead and a second space below the showerhead, and provides a plurality of introduction ports for introducing a gas into the second space and a plurality of openings penetrating the showerhead so that the first space and the second space are in communication with each other; a substrate support portion configured to support a substrate in the second space; an ion trap provided between the upper electrode and the showerhead, wherein the ion trap provides a plurality of through holes arranged not to align with the plurality of openings of the showerhead; a first gas supply portion configured to supply a gas to a region in the first space between the upper electrode and the ion trap; a second gas supply portion configured to supply the showerhead with a gas to be introduced from the plurality of introduction ports into the second space; a power source configured to produce a power for generating plasma, and connected to the upper electrode; and a switch configured to switchably connect the showerhead to one of a ground and the upper electrode.

TECHNICAL FIELD

Exemplary embodiments of the present disclosure relate to a plasma processing device and a plasma processing method.

BACKGROUND

Plasma processing is performed as an example of substrate processing. In the plasma processing, a substrate is processed by chemical species from plasma generated in a chamber. The chemical species in the plasma include ions and radicals. Since ions can damage the substrate, substrate processing may be performed using radicals. Patent Document 1 below discloses a plasma processing device which enables the substrate processing using the radicals.

PRIOR ART DOCUMENTS

Patent Documents

Patent Document 1: Specification of US Patent No. 8207470

SUMMARY

Problems to Be Resolved by the Invention

The present disclosure provides a technique for switchably using remote plasma and direct plasma.

Means for Solving the Problem

In one exemplary embodiment, a plasma processing device is provided. The plasma processing device includes a chamber; an upper electrode; a showerhead; a substrate support portion; an ion trap; a first gas supply portion; a second gas supply portion; a power source; and a switch. The substrate support portion is configured to support a substrate in the chamber. The showerhead is provided below the upper electrode. The shower head divides an internal space of the chamber into a first space between the upper electrode and the showerhead and a second space below the showerhead. The showerhead provides a plurality of introduction ports for introducing a gas into the second space and a plurality of openings penetrating the showerhead so that the first space and the second space are in communication with each other. The substrate support portion is configured to support a substrate in the second space. The ion trap is provided between the upper electrode and the showerhead. The ion trap provides a plurality of through holes arranged not to align with the plurality of openings of the showerhead. The first gas supply portion is configured to supply a gas to an area in the first space between the upper electrode and the ion trap. The second gas supply portion is configured to supply a gas, to be introduced into the second space from the plurality of introduction ports, to the showerhead. The power source is configured to produce power for generating plasma, and is connected to the upper electrode. The switch is configured to switchably connect the showerhead to one of a ground and the upper electrode.

Effect of the Invention

According to one exemplary embodiment, it is possible to switchably use remote plasma and direct plasma.

DETAILED DESCRIPTION

Hereinafter, various exemplary embodiments will be described.

In one exemplary embodiment, a plasma processing device is provided. The plasma processing device includes a chamber; an upper electrode; a showerhead; a substrate support portion; an ion trap; a first gas supply portion; a second gas supply portion; a power source; and a switch. The showerhead is provided below the upper electrode. The shower head divides an internal space of the chamber into a first space between the upper electrode and the showerhead and a second space below the showerhead. The showerhead provides a plurality of introduction ports for introducing a gas into the second space and a plurality of openings penetrating the showerhead so that the first space and the second space are in communication with each other. The substrate support portion is configured to support a substrate in the second space. The ion trap is provided between the upper electrode and the showerhead. The ion trap provides a plurality of through holes arranged not to align with the plurality of openings of the showerhead. The first gas supply portion is configured to supply a gas to a region in the first space between the upper electrode and the ion trap. The second gas supply portion is configured to supply the showerhead with a gas to be introduced into the second space from the plurality of introduction ports. The power source is configured to produce power for generating plasma, and is connected to the upper electrode. The switch is configured to switchably connect the showerhead to one of a ground and the upper electrode.

In the plasma processing device of the embodiment, the plurality of through holes of the ion trap are arranged not to align with the plurality of openings of the showerhead. Therefore, most or all of ions in the plasma generated in the region in the first space are trapped by the ion trap, and not substantially supplied to the second space. Meanwhile, radicals in the plasma generated in the region in the first space are supplied to the second space. Therefore, plasma processing by remote plasma becomes possible with respect to the substrate disposed in the second space. Further, when the showerhead is connected to the upper electrode by the switch, generation of the plasma is not hindered by the ion trap, and the plasma is generated in the second space. Therefore, plasma processing by direct plasma becomes possible with respect to the substrate disposed in the second space.

In one exemplary embodiment, the plasma processing device may further include a controller. The controller may control the switch so as to connect the showerhead to the ground, control the first gas supply portion so as to supply the processing gas to the region in the first space, and control the power source so as to supply the power to the upper electrode. By such a control, the plasma is generated in the first space, and the radicals are supplied from the generated plasma to the second space. The controller may control the switch so as to connect the showerhead to the upper electrode, control the second gas supply portion so as to introduce the processing gas into the second space through the plurality of introduction ports of the showerhead, and control the power source so as to supply the power to the upper electrode. By such a control, generation of the plasma is not hindered by the ion trap, and the plasma is generated in the second space.

Even in another exemplary embodiment, a plasma processing device is provided. The plasma processing device includes a chamber; an upper electrode; a showerhead; a substrate support portion; an ion trap; a first gas supply portion; a second gas supply portion; a first power source; and a second power source. The showerhead is provided below the upper electrode. The shower head divides an internal space of the chamber into a first space between the upper electrode and the showerhead and a second space below the showerhead. The showerhead provides a plurality of introduction ports for introducing a gas into the second space and a plurality of openings penetrating the showerhead so that the first space and the second space are in communication with each other. The showerhead is grounded. The substrate support portion includes an electrode, and is configured to support the substrate in the second space. The ion trap is provided between the upper electrode and the showerhead. The ion trap provides a plurality of through holes arranged not to align with the plurality of openings of the showerhead. The first gas supply portion is configured to supply a gas to a region in the first space between the upper electrode and the ion trap. The second gas supply portion is configured to supply the showerhead with a gas to be introduced into the second space from the plurality of introduction ports. The first power source is configured to produce a first power for generating plasma, and is connected to the upper electrode. The second power source is configured to generate a second power for generating the plasma, and is connected to the electrode of the substrate support portion.

Even in the plasma processing device of the embodiment, plasma processing by remote plasma becomes possible with respect to the substrate disposed in the second space. Further, in the second space, generation of the plasma is not hindered by the ion trap, and the plasma is generated. Therefore, plasma processing by direct plasma becomes possible with respect to the substrate disposed in the second space.

In one exemplary embodiment, the plasma processing device may further include a controller. The controller may control the first gas supply portion so as to supply the processing gas to the region in the first space, and control the first power source so as to supply the first power to the upper electrode. By such a control, the plasma is generated in the first space, and the radicals are supplied from the generated plasma to the second space. The controller may control the second gas supply portion so as to introduce the processing gas into the second space through the plurality of introduction ports of the showerhead, and control the first power source so as to supply the second power to the upper electrode. By such a control, generation of the plasma is not hindered by the ion trap, and the plasma is generated in the second space.

In one exemplary embodiment, the first space may include one or more cavities provided by the upper electrode. The plasma may be generated in the first space by hollow cathode discharge in one or more cavities.

In one exemplary embodiment, the upper electrode may provide one or more grooves opened downward as one or more cavities. Each of one or more grooves has a ring shape, and extends around a central axial line extending in a vertical direction. The upper electrode may provide a plurality of first grooves and a plurality of second grooves opened downward as the one or more cavities. Each of the plurality of first grooves extends in one direction. Each of the plurality of second grooves are extended in different directions to cross the plurality of first grooves.

In one exemplary embodiment, the upper electrode may provide a plurality of holes opened downward as one or more cavities. The plurality of holes are arranged in a circumferential direction around the central axis line extending in the vertical direction or in a grid shape.

In one exemplary embodiment, the ion trap may be made of a conductive material, and may be electrically connected to the showerhead.

In one exemplary embodiment, the ion trap may be made of a dielectric.

In one exemplary embodiment, the plasma processing device may further include a conductive member. The conductive member is extended on a lateral side of the region in the first space, and is electrically connected to the showerhead.

In another exemplary embodiment, a plasma processing method is provided. In the plasma processing method, a plasma processing device of any one of various exemplary embodiments is used. The plasma processing method includes a process of preparing the substrate on the substrate support portion in the second space. The plasma processing method further includes a process of processing the substrate in the second space by radicals. The radicals are supplied to the second space from the plasma generated in the region in the first space through the plurality of through holes of the ion trap and the plurality of openings of the showerhead. The plasma processing method includes a process of processing the substrate in the second space by chemical species. The chemical species are supplied to the substrate from the plasma generated in the second space.

In one exemplary embodiment, the radicals may be used in a film forming. The chemical species may be used in an anisotropic etching.

In one exemplary embodiment, the radicals may be used in an etching. The chemical species may be used in an anisotropic etching.

In one exemplary embodiment, the plasma processing method may further include a process of processing the substrate in the second space by other radicals. The other radicals may be supplied to the second space from the plasma generated in the region in the first space through the plurality of through holes of the ion trap and the plurality of openings of the showerhead, and may be used in a film forming.

Hereinafter, various exemplary embodiments will be described in detail with reference to drawings. Further, in each drawing, the same or equivalent part will be denoted by the same reference numeral.

FIG.1is a diagram schematically illustrating a plasma processing device according to one exemplary embodiment. The plasma processing device1illustrated inFIG.1includes a chamber10. The chamber10has an approximately cylindrical shape. The chamber10is made of a conductive material such as aluminum. The chamber10may be grounded. The chamber10provides an internal space10stherein.

The plasma processing device1further includes an upper electrode12. The upper electrode12is extended above a substrate support portion16described later. In one embodiment, the upper electrode12closes a top opening of the chamber jointly with a member13. The upper electrode12has an approximately disk shape, and is made of the conductive material such as aluminum. The member13is made of an insulating material. The member13is interposed between a top of the chamber10and the upper electrode12.

The plasma processing device1further includes a shower head14. The shower head14is provided below the upper electrode12. The shower head14has the approximately disk shape. The shower head14is made of the conductive material such as aluminum. The shower head14divides the internal space10sinto a first space S1and a second space S2. The first space S1is a space between the upper electrode12and the shower head14. The second space S2is a space below the shower head14.

In one embodiment, a member15may be provided between the upper electrode12and the shower head14. The member15has the cylindrical shape, and is made of an insulating material such as conductor such as aluminum oxide. The first space S1is a space between the upper electrode12and the shower head14, and inside the member15.

The shower head14provides a plurality of introduction ports14iand a plurality of openings14h. The plurality of introduction ports14iis formed in the shower head14in order to introduce a gas into the second space S2. The plurality of openings14his formed in the shower head14so as for the first space S1and the second space S2to be in communication with each other.

The chamber10has a side wall. The side wall of the chamber10provides a passage 10p. When the substrate W is transported between the second space S2and the outside of the chamber10, the substrate W passes through the passage 10p. The plasma processing device1may further includes a gate valve10g. The gate valve10gis provided along the side wall of the chamber10in order to open/close the passage 10p.

The plasma processing device1further includes the substrate support portion16. The substrate support portion16is configured to support the substrate W in the second space S2. The substrate W may have the approximately disk shape. The substrate W is processed in a state of being mounted on the substrate support portion16in the second space S2. The substrate support portion16may be made of insulating ceramics such as aluminum nitride. Alternatively, the substrate support portion16may be made of the conductive material.

In one embodiment, the substrate support portion16may be supported by a support member17. The support member17may be extended upward from the bottom of the chamber10. The substrate support portion16may have a heater16h. The heater16his provided inside the substrate support portion16. The heater16his configured to receive a power supplied from a heater power source. The heater16his configured to heat the substrate W on the substrate support portion16at a predetermined temperature.

In one embodiment, the substrate support portion16may further include an electrode16e. The electrode163is provided inside the substrate support portion16. Further, when the substrate support portion16is made of the conductive material, the substrate support portion16serves as the electrode16e.

The plasma processing device1further includes an ion trap18. The ion trap18is provided between the upper electrode12and the shower head14. In one embodiment, the ion trap18may be made of the conductive material such as aluminum. The ion trap has the approximately disk shape. The ion trap18divides the first space S1into a region R1and a region R2. The region R1is a region between the upper electrode12and the ion trap18, and the region R2is a region between the ion trap18and the shower head14.

The ion trap18provides a plurality of through holes18h. The plurality of through holes18hare arranged not to align with the plurality of openings14h, respectively. That is, the bottoms of the plurality of through holes18hare arranged not to face the tops of the plurality of openings14h, respectively. In other words, the plurality of through holes18hand the plurality of openings14hare arranged so that figures acquired by projecting the through holes and the openings on a plane parallel to the substrate W do not overlap with each other. The ion trap18captures ions from plasma generated inside the region R1in the first space S1, and prevents invasion of the ions into the second space S2from the region R1. Meanwhile, the ion trap18permits radicals from the plasma generated inside the region R1in the first space S1to pass through the second space S2.

In one embodiment, an inner wall surface of the chamber10, a surface of the upper electrode12, a surface of the shower head14, and a surface of the ion trap18may be covered with a member having corrosion resistance. The member may be an alumite film or an oxide yttrium film.

The plasma processing device1further includes the first gas supply portion20. The first gas supply portion20is configured to supply a gas to the region R1. In one embodiment, the first gas supply portion20is connected to the gas introduction ports of the upper electrode12, and supplies the gas to the region R1through the gas introduction ports.

The plasma processing device1further includes the second gas supply portion22. The second gas supply portion22is configured to supply the gas to the shower head14. In one embodiment, the second gas supply portion22is connected to the shower head14through a pipe23, and supplies the gas to the shower head14through the pipe23. The gas supplied to the shower head14from the second gas supply portion22is introduced into the second space S2from the plurality of introduction ports14iwhich are in communication with each other in the shower head14.

The plasma processing device1includes one or more power sources in order to produce the plasma from the gas inside the chamber10. One or more power sources are connected to the upper electrode12. In one embodiment, the plasma processing device1may include a high-frequency power source24and a DC pulse power source26, as one or more power sources.

The high-frequency power source24generates high-frequency power (hereinafter, may be referred to as “first high-frequency power”) used for generating the plasma. The high-frequency power source24is connected to the upper electrode12. The first high-frequency power is supplied to the upper electrode12. A frequency of the first high-frequency power may be 300 kHz or more and 100 MHz or less. In one example, the frequency of the first high-frequency power may be 40 MHz.

The high-frequency power source24may be connected to the upper electrode12through a matcher24m. The matcher24mincludes a matching circuit for matching a load-side impedance of the high-frequency power source24with an output impedance of the high-frequency power source24.

The DC pulse power source26intermittently or periodically generates a pulse-shaped DC voltage. The DC pulse power source26is connected to the upper electrode12. The pulse-shaped DC voltage generated by the DC pulse power source26is applied to the upper electrode12. The pulse-shaped DC voltage may have a positive polarity or a negative polarity. A frequency for determining a period of the pulse-shaped DC voltage applied to the upper electrode12is 10 Hz or more and 1 MHz or less. The frequency is a reverse number of the period of the pulse-shaped DC voltage applied to the upper electrode12. In one example, the frequency may be 500 kHz.

In one embodiment, the DC pulse power source26may include a DC power source26aand a pulse unit26b. The DC power source26ais a poser source that generates the DC voltage. The DC power source26ais a variable DC power source. The pulse unit26bis connected between the DC power source26aand the upper electrode12. The pulse unit26bis configured to modulate the DC voltage from the DC power source26ato the pulse-shaped DC voltage. The pulse unit26bmay be constituted by one or more switching transistors.

In one embodiment, the DC pulse power source26may be connected to the upper electrode12through a filter26f. The filter26fis an electric filter that blocks or attenuates the high-frequency power.

The plasma processing device1further includes a switch28. The switch is configured to switchably connect the shower head14to one of a ground and the upper electrode12.

In one embodiment, the plasma processing device1may further include a high-frequency power source30. The high-frequency power source30is a power source that generates high-frequency power (hereinafter, may be referred to as “second high-frequency power”). The high-frequency power source30is connected to the electrode16e. The second high-frequency power is supplied to the electrode16e. The frequency of the second high-frequency power is 300 kHz or more and 100 MHz or less. In one example, the frequency of the second high-frequency power may be 400 kHz.

The high-frequency power source30may be connected to the electrode16ethrough a matcher30m. The matcher30mincludes a matching circuit for matching a load-side impedance of the high-frequency power source30with an output impedance of the high-frequency power source30.

In one embodiment, the plasma processing device1may further include an exhaust device32. The exhaust device32is connected to the internal space10sof the chamber10through an exhaust pipe33. The exhaust device32may include one or more pumps such as a dry pump and a turbo molecular pump, and a pressure controller such as an automatic pressure control valve. In one embodiment, the exhaust device32may be connected to the second space S2through the exhaust pipe33and an exhaust port10e. The exhaust port10emay be provided on the bottom of the chamber10.

In one embodiment, the plasma processing device1may further include a controller40. The controller40is configured to control each portion of the plasma processing device1. The controller40may be a computer having a processor, an input device, an output device, a display device, and a storage device. The storage device stores a control program and recipe data. The processor executes the control program, and controls each portion of the plasma processing device1according to the recipe data. As a result, in the plasma processing device1, plasma processing according to the recipe data is executed. A plasma processing method according to various exemplary embodiments described later may be executed in the plasma processing device1by controlling each portion of the plasma processing device1by the controller40.

FIG.2is a diagram illustrating remote plasma generated in a plasma processing device according to one exemplary embodiment. In the plasma processing device1, when the substrate W is processed by using radicals supplied to the second space S2from plasma (remote plasma RP) generated in the region R1, the switch28connects the shower head14to the ground. Further, the gas from the first gas supply portion20is supplied to the region R1. Further, the exhaust device32reduces a pressure inside the internal space10sto a specified pressure. In addition, one or both of the first high-frequency power and the pulse-shaped DC voltage are given to the upper electrode12. To this end, the controller40may control the switch28, the first gas supply portion20, the high-frequency power source24, the DC pulse power source26, and the exhaust device32. A high-frequency electric field is formed inside the region R1, i.e., between the upper electrode12and the shower head14. In the region R1, the gas is excited by the high-frequency electric field and the plasma is generated. The substrate W mounted on the substrate support portion16in the second space S2is processed in the second space S2by the radicals from the plasma generated in the region R1, i.e., the remote plasma RP.

FIG.3is a diagram illustrating direct plasma generated in a plasma processing device according to one exemplary embodiment. In the plasma processing device1, when the substrate W is processed by using chemical species from plasma (direct plasma DP) generated in the second space S2, the switch28connects the shower head14to not the ground but the upper electrode12. Further, the gas from the second gas supply portion22is supplied to the second space S2from the shower head14. Further, the exhaust device32reduces a pressure inside the internal space10sto a specified pressure. In addition, one or both of the first high-frequency power and the pulse-shaped DC voltage are supplied to the shower head14through the upper electrode12. Further, the second high-frequency power may be supplied to the electrode16e. To this end, the controller40may control the switch28, the second gas supply portion22, the high-frequency power source24, the DC pulse power source26, the exhaust device32, and the high-frequency power source30. The high-frequency electric field is formed inside the second space S2, i.e., in a space between the shower head14and the electrode16e. In the second space S2, the gas is excited by the high-frequency electric field and the plasma is generated. The substrate W mounted on the substrate support portion16in the second space S2is processed in the second space S2by the chemical species from the plasma generated in the second space S2, i.e., the direct plasma DP.

In the plasma processing device1, the plurality of through holes18hof the ion trap18are arranged not to be align with the plurality of openings14hof the shower head14. Therefore, most or all of ions in the plasma generated in the region R1in the first space S1are captured by the ion trap18, and not substantially supplied to the second space S2. Meanwhile, radicals in the plasma generated in the region R1in the first space S1are supplied to the second space. Therefore, according to the plasma processing device1, plasma processing by the remote plasma RP for the substrate disposed in the second space S2becomes possible. Further, when the shower head14is connected to the upper electrode12by the switch28, generation of the plasma is not hindered by the ion trap, and the plasma is generated in the second space S2. Therefore, according to the plasma processing device1, plasma processing by the direct plasma DP for the substrate W disposed in the second space S2becomes possible.

Further, the ion trap18is not interposed between the shower head14and the electrode16e. Therefore, when the direct plasma DP is generated, the ion trap18does not influence the high-frequency electric field formed between the shower head14and the electrode16e. Further, when processing by the remote plasma RP and processing by the direct plasma DP are consecutively performed in the same chamber, a high throughput is obtained and an influence on a process by a change in environment around the substrate W is suppressed.

Hereinafter, a plasma processing device according to another exemplary embodiment will be described with reference toFIG.4.FIG.4is a diagram schematically illustrating a plasma processing device according to another exemplary embodiment. In the following description, a difference of the plasma processing device1B illustrated inFIG.4from the plasma processing device1will be described.

In the plasma processing device1B, the ion trap18is made of a dielectric such as quartz or aluminum oxide other than the conductive material. The plasma processing device1B may further include a conductive member50. The conductive member50is extended on the side of the region R1in the first space S1. The conductive member50may have, for example, the cylindrical shape. The conductive member50may be extended along an inner peripheral surface of the member15. The conductive member50is electrically connected to the shower head14.

According to the plasma processing device1B, the plasma processing by the radicals from the remote plasma RP for the substrate disposed in the second space S2becomes possible like the plasma processing device1. Further, according to the plasma processing device1B, the plasma processing by the chemical species from the direct plasma DP for the substrate W disposed in the second space S2becomes possible like the plasma processing device1.

Hereinafter, a plasma processing method according to various exemplary embodiments will be described. In various exemplary embodiments, the plasma processing method may be executed by using the plasma processing device1or the plasma processing device1B. In various exemplary embodiments, the plasma processing method includes a process of preparing a substrate. The plasma processing method further includes at least one of a remote plasma processing process and a direct plasma processing process.

In the substrate preparation process, the substrate W is mounted on the substrate support portion16in the second space S2. The remote plasma processing process and the direct plasma processing process are performed in the state in which the substrate W is mounted on the substrate support portion16.

In the remote plasma processing process, the substrate W is processed by the radicals in the second space S2. The radicals are supplied to the second space S2from the plasma generated in the region R1in the first space S1, i.e., the remote plasma RP through the plurality of through holes18hof the ion trap18and the plurality of openings14hof the shower head14. The radicals from the remote plasma RP may be used in a film forming for the substrate W. Alternatively, the radicals from the remote plasma RP may be used in an etching for the substrate W. The etching by the radicals from the remote plasma RP may be an isotropic etching.

In the direct plasma processing process, the substrate W is processed by the chemical specifies in the second space S2. The chemical specifies are supplied to the substrate W from the plasma generated in the second space S2, i.e., the direct plasma DP. The chemical species from the direct plasma DP may be used in the anisotropic etching for the substrate W. Alternatively, the chemical species from the direct plasma DP may be used in the film forming for the substrate W.

In one embodiment, the plasma processing method may further include another remote plasma processing process. In another remote plasma processing process, the substrate W is processed by the radicals in the second space S2like the remote plasma processing process. The radicals are supplied to the second space S2from the plasma generated in the region R1in the first space S1, i.e., the remote plasma RP through the plurality of through holes18hof the ion trap18and the plurality of openings14hof the shower head14. In another remote plasma processing process, the radicals from the remote plasma RP may be used in a film forming for the substrate W. Another remote plasma processing process may be performed after the anisotropic etching for the substrate W in the direct plasma processing process and the isotropic etching for the substrate W in the remote plasma processing process.

Hereinafter, first to fifth embodiments of the plasma processing method will be described.

In the first embodiment, the plasma processing method includes a remote plasma processing process and a direct plasma processing process. In the remote plasma processing process, the radicals from the remote plasma RP are used in a film forming for the substrate W in the second space S2. In the continued direct plasma processing process, the chemical specifies from the direct plasma DP is used in an anisotropic etching for the substrate W in the second space S2.

In the second embodiment, the plasma processing method includes a remote plasma processing process and a direct plasma processing process. In the remote plasma processing process, the radicals from the remote plasma RP are used in an isotropic etching for the substrate W in the second space S2. In the continued direct plasma processing process, the chemical specifies from the direct plasma DP are used in an anisotropic etching for the substrate W in the second space S2.

In the third embodiment, the plasma processing method includes a direct plasma processing process and a remote plasma processing process. In the direct plasma processing process, the chemical specifies from the direct plasma DP are used in a film forming for the substrate W in the second space S2. In the continued remote plasma processing process, the radicals from the remote plasma RP are used in an isotropic etching for the substrate W in the second space S2.

In the fourth embodiment, the plasma processing method includes a remote plasma processing process and a direct plasma processing process. In the remote plasma processing process, the radicals from the remote plasma RP is used in a film forming for the substrate W in the second space S2. In the continued direct plasma processing process, the chemical specifies from the direct plasma DP are used in a film forming for the substrate W in the second space S2. The fourth embodiment may be executed for selective film forming on a specific region of the substrate W.

In the fifth embodiment, the plasma processing method includes a first remote plasma processing process and a second remote plasma processing process. In the first remote plasma processing process, the radicals from the remote plasma RP are used in an isotropic etching for the substrate W in the second space S2. In the continued second remote plasma processing process, radicals from another remote plasma RP are used in a film forming for the substrate W in the second space S2.

Hereinafter, an application example for several examples of the plasma processing method according to various exemplary embodiments will be described.

First, the application example is described with reference toFIGS.5A to5D.FIGS.5A to5Dare partially enlarged cross-sectional views of a substrate of one example for describing a plasma processing method according to one exemplary embodiment. In one embodiment, the plasma processing method is applied to the substrate100illustrated inFIG.5A. The plasma processing method applied to the substrate100illustrated inFIG.5Ais based on the first embodiment.

The substrate100illustrated inFIG.5Ahas a base region101and a mask102. The mask102is provided on the base region101. The mask102is a photoresist mask or a mask formed by an organic film. The mask102is patterned to partially expose an upper surface of the base region101. The base region101includes a film to be etched. The film may be a silicon contained film. When the mask102is a photoresist mask, the silicon contained film of the base region101includes an anti-reflective film. When the mask102is the mask formed by an organic film, the silicon contained film of the base region101includes a silicon nitride film or a silicon oxide film.

In the substrate preparation process of the plasma processing method, the substrate100is prepared on the substrate support portion16as the substrate W. Processes described below in the plasma processing method are executed in a state in which the substrate100is mounted on the substrate support portion16.

The plasma processing method includes a film forming process and an etching process. The film forming process includes a precursor gas supply process and a remote plasma processing process. In the precursor gas supply process, a precursor gas is supplied to the substrate100. The precursor gas is a gas including a precursor. The precursor contains silicon. The precursor includes, for example, aminosilane. The aminosilane is, for example, bistertbutylaminosilane (BTBAS). The aminosilane may be bisdiethylaminosilane (BDEAS), bismethylaminosilane (BDMAS), di-isopropylamino silane (DIPAS), or bisethylaminosilane (BEMAS). In the precursor gas supply process, the precursor in the precursor gas is adsorbed on the surface of the substrate100.

In the remote plasma processing process, plasma, i.e., the remote plasma RP is generated in the region R1. The remote plasma RP is formed by a reforming gas. The reforming gas is an oxygen contained gas or a nitrogen contained gas. In this process, oxygen radicals or nitrogen radicals from the remote plasma RP are supplied to the second space S2and oxidize or nitrate the precursor. As a result, a spacer film103is formed on the surface of the substrate100as illustrated inFIG.5B. The spacer film103is a silicon oxide film or a silicon nitride film.

Further, in the film formation process, the precursor gas supply process and the remote plasma processing process may be repeated alternately. Further, the film forming process may include a purge process between the precursor gas supply process and the remote plasma processing process, and between the remote plasma processing process and the precursor gas supply process. In the purge process, a purge in the chamber10is performed.

The etching process is performed after the film forming process. The etching process is a type of direct plasma processing process. In the etching process, the spacer film103is etched by the chemical species from the plasma generated from the processing gas in the second space S2, i.e., the direct plasma DP. The processing gas used in the etching process for the spacer film103includes fluorocarbon gas and/or hydrofluorocarbon gas. The processing gas may contain another gas such as rare gas. In the etching process, the anisotropic etching of the spacer film103is performed. In the etching process, as illustrated inFIG.5C, the spacer film103is etched so as to leave a region103swhich is a part of the spacer film103as illustrated inFIG.5C. The region103sis extended along a side surface of the mask102. In the etching process, the second high-frequency power may be supplied to the electrode16ein order to attract ions into the substrate100.

The plasma processing method may further include a mask removal process. The mask removal process is a type of direct plasma processing process. In the mask removal process, the mask102is etched by the chemical species from the plasma generated from the processing gas in the second space S2, i.e., the direct plasma DP. The processing gas used in the mask removal process includes at least one of oxygen, nitrogen, hydrogen, and ammonia. In the mask removal process, the mask102is etched and removed as illustrated inFIG.5D. As a result, the region103sis left as a new mask on the base region101. That is, in the plasma processing method, the mask is formed by double patterning.

Next,FIGS.6A to6FandFIGS.7A to7Eare referenced.FIGS.6A to6FandFIGS.7A to7Eare partially enlarged cross-sectional views of a substrate of one example for describing a plasma processing method according to another exemplary embodiment. In one embodiment, the plasma processing method is applied to the substrate200illustrated inFIG.6A. The plasma processing method applied to the substrate200illustrated inFIG.6Ais based on the second and fifth embodiments. The plasma processing method may be executed in order to manufacture a3D NAND device.

The substrate200illustrated inFIG.6Ahas a base region201and a multilayer film202. The base region201is made of, for example, silicon. The multilayer film202includes a plurality of first layers203and a plurality of second layers204. The plurality of first layers203and the plurality of second layers204are stacked alternately on the base region201. The plurality of first layers203is made of silicon oxide. The plurality of second layers204is made of silicon nitride. The substrate200may further have a mask provided on the multilayer film202.

In the substrate preparation process of the plasma processing method, the substrate200is prepared on the substrate support portion16as the substrate W. Processes described below in the plasma processing method may be executed in a state in which the substrate200is mounted on the substrate support portion16.

Next, in the plasma processing method, a first etching process is executed. The first etching process may be a type of direct plasma processing process. In the first etching process, the multilayer film202is etched by the chemical species the plasma generated from the processing gas in the second space S2, i.e., the direct plasma DP. Processing gas used in the first etching process is gas containing fluorine or hydrogen. For example, the processing gas contains fluorocarbon gas and hydrofluorocarbon gas. The processing gas may contain another gas such as rare gas. In the first etching process, the anisotropic etching of the multilayer film202is performed. In the first etching process, a hole205is formed in the multilayer film202as illustrated inFIG.6B. The hole205may be a channel hole. In the first etching process, the second high-frequency power may be supplied to the electrode16ein order to attract ions into the substrate200. Further, the first etching process may be executed by using a plasma processing device different from the plasma processing device1and the plasma processing device1B.

Next, in the plasma processing method, a first film forming process is executed. In the first film forming process, a film206is formed on a wall surface partitioning the hole205as illustrated inFIG.6C. The film206is a polycrystalline silicon film. The film206may be formed by a CVD method or an ALD method. The plasma processing device1or the plasma processing device1B may be used for forming the film206. Alternatively, another film forming device may be used for forming the film206.

Next, in the plasma processing method, a first embedding process is executed. In the first embedding process, the hole205is buried by the silicon oxide and a region207made of the silicon oxide is formed in the hole205, as illustrated inFIG.6D. The region207may be formed by the CVD method or the ALD method. The plasma processing device1or the plasma processing device1B may be used for forming the region207. Alternatively, another film forming device may be used for forming the region207.

Next, in the plasma processing method, another mask is formed on the multilayer film202. Another mask may have a multilayer structure including a photoresist layer, an SiON layer, and an amorphous carbon layer. Another mask is formed by lithography technology.

Next, in the plasma processing method, a second etching process is executed. The second etching process may be a type of direct plasma processing process. In the second etching process, the plasma processing device1or the plasma processing device1B is used. Further, when a process before the second etching process is executed by using a different device from the plasma processing device1or the plasma processing device1B, the substrate preparation process is executed just before the second etching process. In the substrate preparation process, the substrate200is prepared on the substrate support portion16as the substrate W.

In the second etching process, the multilayer film202is etched by the chemical species from the plasma generated from the processing gas in the second space S2, i.e., the direct plasma DP. Processing gas used in the second etching process is gas containing fluorine or hydrogen. For example, the processing gas contains fluorocarbon gas and hydrofluorocarbon gas. The processing gas may contain another gas such as rare gas. In the second etching process, the anisotropic etching of the multilayer film202is performed. In the second etching process, a hole208is formed in the multilayer film202as illustrated inFIG.6E. In the second etching process, the second high-frequency power may be supplied to the electrode16ein order to attract ions into the substrate200.

Next, in the plasma processing method, a third etching process is executed. The third etching process may be a type of remote plasma processing process. In the third etching process, a plurality of second layers204is etched by the radicals from the plasma generated from the processing gas in the first space S1, i.e., the remote plasma RP. Processing gas used in the third etching process is gas containing fluorine or hydrogen. The processing gas includes, for example, NF3, H2, and O2. Alternatively, the processing gas may include fluorocarbon, N2, H2, and O2. In the third etching process, the plurality of second layers204is etched selectively or isotropically with respect to the plurality of first layers203as illustrated inFIG.6F.

Next, in the plasma processing method, a second film forming process is executed. The second film forming process includes a precursor gas supply process and a remote plasma processing process. In the precursor gas supply process in the second film forming process, precursor gas is supplied to the substrate200. The precursor gas is gas including a precursor. The precursor contains silicon. The precursor includes, for example, aminosilane. The aminosilane is, for example, bistertbutylaminosilane (BTBAS). The aminosilane may be bisdiethylaminosilane (BDEAS), bismethylaminosilane (BDMAS), di-isopropylamino silane (DIPAS), or bisethylaminosilane (BEMAS). In the precursor gas supply process in the second film forming process, the precursor in the precursor gas is adsorbed on the surface of the substrate200.

In the remote plasma processing process in the second film forming process, plasma, i.e., the remote plasma RP is generated in the region R1. The remote plasma RP is formed by reforming gas. The reforming gas is oxygen contained gas. In this process, oxygen radicals from the remote plasma RP are supplied to the second space S2and oxidize the precursor. As a result, as illustrated inFIG.7A, a silicon oxide film is formed in the hole208, and a region of the plurality of first layers203is enlarged. The silicon oxide film formed in the second film forming process provides a tunnel oxide film209.

Further, in the second film formation process, the precursor gas supply process and the remote plasma processing process may be repeated alternately. Further, the second film forming process may include a purge process between the precursor gas supply process and the remote plasma processing process, and between the remote plasma processing process and the precursor gas supply process. In the purge process, a purge in the chamber10is performed.

Next, in the plasma processing method, a third film forming process is executed. The third film forming process includes a precursor gas supply process and a remote plasma processing process. In the precursor gas supply process in the third film forming process, precursor gas is supplied to the substrate200. The precursor gas is gas including a precursor. The precursor contains silicon. The precursor includes, for example, aminosilane. The aminosilane is, for example, bistertbutylaminosilane (BTBAS). The aminosilane may be bisdiethylaminosilane (BDEAS), bismethylaminosilane (BDMAS), di-isopropylamino silane (DIPAS), or bisethylaminosilane (BEMAS). In the precursor gas supply process in the third film forming process, the precursor in the precursor gas is adsorbed on the surface of the substrate200.

In the remote plasma processing process in the third film forming process, plasma, i.e., the remote plasma RP is generated in the region R1. The remote plasma RP is formed by reforming gas. The reforming gas is nitrogen contained gas. The nitrogen contained gas is N2gas or NH3gas. In this process, nitrogen radicals from the remote plasma RP are supplied to the second space S2and nitrate the precursor. As a result, a silicon nitride film210is formed on the surface of the substrate200as illustrated inFIG.7B. The silicon nitride film210may be a charge trap film.

Further, in the third film formation process, the precursor gas supply process and the remote plasma processing process may be repeated alternately. Further, the third film forming process may include a purge process between the precursor gas supply process and the remote plasma processing process, and between the remote plasma processing process and the precursor gas supply process. In the purge process, a purge in the chamber10is performed.

Next, in the plasma processing method, a fourth film forming process is executed. In the fourth film forming process, a high dielectric film211is formed on the surface of the substrate200as illustrated inFIG.7C. The fourth film forming process is executed by using the plasma processing device1or the plasma processing device1B. The fourth film forming process includes a precursor gas supply process and a remote plasma processing process. That is, in the fourth film forming process, the precursor is adsorbed on the surface of the substrate200in the precursor gas supply process and the precursor is reformed by the radicals from the remote plasma RP in the remote plasma processing process.

As a result, the high dielectric film211is formed. Further, in the fourth film formation process, the precursor gas supply process and the remote plasma processing process may be repeated alternately. Further, the fourth film forming process may include the purge process between the precursor gas supply process and the remote plasma processing process, and between the remote plasma processing process and the precursor gas supply process. In the purge process, the purge in the chamber10is performed.

Next, in the plasma processing method, a second embedding process is executed. In the second embedding process, a region212is formed on the surface of the high dielectric film211. In the second embedding process, a space in the substrate200is buried in the region212as illustrated inFIG.7D. The region212is made of, for example, tantalum. The region212may be formed by the CVD method or the ALD method.

Next, in the plasma processing method, a fourth etching process is executed. The fourth etching process may be a type of direct plasma processing process. In the fourth etching process, the region212is etched by the chemical species the plasma generated from the processing gas in the second space S2, i.e., the direct plasma DP. In the fourth etching process, the region212is formed in a hole208as illustrated inFIG.7E. In the fourth etching process, the second high-frequency power may be supplied to the electrode16ein order to attract ions into the substrate200. Further, the first etching process may be executed by using a plasma processing device different from the plasma processing device4or the plasma processing device1B.

Hereinafter,FIGS.8and9are referenced. Each ofFIGS.8and9is a diagram schematically illustrating a plasma processing device according to yet another exemplary embodiment. A plasma processing device1C illustrated inFIG.8and a plasma processing device1D illustrated inFIG.9may be used in the plasma processing methods according to various embodiments and various examples described above, respectively. Hereinafter, a difference of the plasma processing device1C from the plasma processing device1will be described. Further, a difference of the plasma processing device1D from the plasma processing device1B will be described.

In the plasma processing device1C and the plasma processing device1D, the shower head14is grounded. The shower head14may be grounded through the member52and the chamber10. The member52may be made of metal such as aluminum. The member52may have a ring shape. The member52is extended between a peripheral portion of the shower head14and the side wall of the chamber10so as to connect the peripheral portion of the shower head14and the side wall of the chamber10. The member52prevents the plasma from being spread to an upper side of the member52or the side of the first space (or the side of the member15).

In the plasma processing device1C and the plasma processing device1D, one or both of the high-frequency power source24and the DC pulse power source constitute a first power source. One or both of the first high-frequency power from the high-frequency power source24and the pulse-shaped DC voltage from the DC pulse power source26are supplied to the upper electrode12as the first power in order to generate the remote plasma RP in the region R1.

In the plasma processing device1C and the plasma processing device1D, the high-frequency power source30constitutes a second power source. The second high-frequency power from the high-frequency power source30is supplied to the electrode16ein order to generate the direct plasma DP in the second space S2.

In the plasma processing device1C and the plasma processing device1D, when the substrate W is processed by using the radicals supplied to the second space S2from the remote plasma RP generated in the region R1, the gas from the first gas supply portion20is supplied to the region R1. Further, the exhaust device32reduces a pressure inside the internal space10sto a specified pressure. In addition, one or both of the first high-frequency power and the pulse-shaped DC voltage are given to the upper electrode12. To this end, the controller40may control the first gas supply portion20, the high-frequency power source24, the DC pulse power source26, and the exhaust device32.

In the plasma processing device1C and the plasma processing device1D, when the substrate W is processed by using the chemical species from the direct plasma DP generated in the second space S2, the gas from the second gas supply portion22is supplied to the second space S2from the shower head14. Further, the exhaust device32reduces a pressure inside the internal space10sto a specified pressure. In addition, the second high-frequency power is supplied to the electrode16e. To this end, the controller40may control the second gas supply portion22, the exhaust device32, and the high-frequency power source30.

Hereinafter,FIG.10, andFIGS.11A to11Dare referenced.FIG.10is a diagram illustrating an upper electrode according to another exemplary embodiment. Each ofFIGS.11A to11Dis a plan view illustrating one or more cavities in the upper electrode according to another exemplary embodiment. An upper electrode12E illustrated inFIG.10may be adopted instead of the upper electrode12in the plasma processing device1, the plasma processing device1B, the plasma processing device1C, and the plasma processing device1D.

The upper electrode12E provides one or more cavities12c. One or more cavities12care included in the region R1. In the illustrated example, the upper electrode12E provides a plurality of cavities12c. One or more cavities12cof the upper electrode12E is formed to generate hollow cathode discharge therein.

In one embodiment, the upper electrode12E includes a main portion12m. The main portion12mhas an approximately disk shape, and is extended above the shower head14and the ion trap18so as to partition the first space S1. The main portion12mprovides one or more cavities12c. One or more cavities12care opened downward.

In one embodiment, the upper electrode12E further provides a flow path12tand a gas diffusion space12d. The flow path12tmay be extended around the pipe23. The flow path12tis connected to the gas diffusion space12d. The upper electrode12E may further include a lid portion12u. The lid portion12uis provided on the main portion12mso as to provide the gas diffusion space12dbetween the main portion12mand the lid portion12u. The gas diffusion space12dis connected to one or more cavities12cthrough one or more holes12h. One or more holes12hare provided by the main portion12m. The gas from the first gas supply portion20is supplied to one or more cavities12cthrough the flow path12t, the gas diffusion space12d, and one or more holes12h.

The upper electrode12E may provide a plurality of holes arranged along one or more concentric circles as the plurality of cavities12cas illustrated inFIG.11A. That is, the plurality of cavities12cmay be a plurality of holes arranged in a circumferential direction around a central axis line. Each of the plurality of holes may have a circular planar shape. Alternatively, the upper electrode12E may provide one or more ring-shaped grooves extended around the central axis line as one or more cavities12cas illustrated inFIG.11B. Alternatively, the upper electrode12E may provide a plurality of holes arranged in a grid shape as the plurality of cavities12cas illustrated inFIG.11C. Alternatively, the upper electrode12E may provide a plurality of first grooves121and a plurality of second grooves122opened downward as one or more cavities12cas illustrated inFIG.11D. Each of the plurality of first grooves121is extended in one direction. The plurality of second grooves122are extended in different directions to cross the plurality of first grooves121, respectively.

Hereinafter,FIG.12is referenced.FIG.12is an enlarged cross-sectional view of one or more cavities in the upper electrode according to another exemplary embodiment. The gas from the first gas supply portion20is supplied to the inside of one or more cavities12c, and when the first high-frequency power and/or the pulse-shaped DC voltage are given to the upper electrode12E, the plasma PL is generated inside one or more cavities12c.

Each of one or more cavities12chas a width Wc and a depth Dc. The Wc may satisfy Wc>λ+2ds. λ represents an average free process of electrons and dsrepresents a thickness of a sheath. When argon gas is used as the processing gas in 133 Pa (1 Torr) and 200° C., λ is 0.44 mm. Further, when an electron density is 1×1011cm−3, a sheath potential is 100 V, an electron temperature is 3 eV, dsis 2.6 mm. Further, the electron density and the sheath potential are values derived when the first high-frequency power has a frequency of 450 kHz and a power level of 500 W, and the pressure of the argon gas is 133 Pa (1 Torr). Therefore, the width We is, for example, 6 mm or more. The depth Dc is, for example, approximately 10 mm.

By the upper electrode12E, high-density remote plasma may be generated by the hollow cathode discharge. Therefore, it is possible to supply a large quantity of radicals to the substrate W disposed in the second space S2from the remote plasma.

Hereinabove, various embodiments have been described, but the present disclosure is not limited to the exemplary embodiment, but various additions, omissions, substitutions, and changes may be made. Further, it is possible to form another embodiment by combining elements in different embodiments.

For example, even when any one of plasma processing by the remote plasma RP and the direct plasma DP is generated, the gas may be supplied from both of the first gas supply portion20and the second gas supply portion22.

For example, the plasma processing device1, the plasma processing device1B, the plasma processing device1C, and the plasma processing device1D may be configured to perform cleaning of the chamber10by using the radicals from the remote plasma RP.

From the above description, it will be understood that various embodiments of the present disclosure are described in the present specification for the purpose of the description, and that various changes can be made without departing from the scope and the spirit of the present disclosure. Therefore, it is not intended to limit the various embodiments disclosed in the present specification, and the true scope and spirit are indicated by the appended claims.

DESCRIPTION OF REFERENCE NUMERALS

1: Plasma processing device10: Chamber12: Upper electrode14: Shower head16: Substrate support portion18: Ion trap20: First gas supply portion22: Second gas supply portion24: High-frequency power source26: DC pulse power source28: Switch