Exemplary embodiments of the present disclosure relate to an etching method, a plasma processing apparatus, a substrate processing system, and non-transitory computer program product.
Manufacturing electronic devices may perform substrate etching. Etching is to be performed selectively. A second region of a substrate is to be etched selectively, while a first region of the substrate is being protected. Patent Literature references 1 and 2 describe techniques for etching a second region formed from silicon oxide selectively with respect to a first region formed from silicon nitride. The techniques described in the references use a fluorocarbon deposited on the first region and the second region of the substrate. The fluorocarbon deposited on the first region is used for protecting the first region, and the fluorocarbon deposited on the second region is used for etching the second region.
Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2015-173240
Patent Literature 2: Japanese Unexamined Patent Application Publication No. 2016-111177
The present disclosure is directed to various techniques for etching a second region of a substrate while protecting a first region of the substrate selectively with respect to the second region.
An etching method according to one exemplary embodiment includes (a) providing a substrate. The substrate includes a first region and a second region. The second region contains silicon oxide, and the first region contains a material different from a material for the second region. The etching method further includes (b) forming a deposit preferentially on the first region with first plasma generated from a first process gas containing a carbon monoxide gas. The etching method further includes (c) etching the second region.
The techniques according to the above exemplary embodiment, and other embodiments, allows etching of the second region of the substrate while protecting the first region of the substrate selectively with respect to the second region.
Exemplary embodiments will now be described.
An etching method according to one exemplary embodiment includes (a) providing a substrate. The substrate includes a first region and a second region. The second region contains silicon oxide, and the first region contains a material different from a material for the second region. The etching method further includes (b) forming a deposit preferentially on the first region with first plasma generated from a first process gas containing a carbon monoxide gas. The etching method further includes (c) etching the second region.
In the above embodiment, a carbon chemical species generated from the first process gas is deposited preferentially on the first region. The carbon chemical species generated from the first process gas is less likely to be deposited on the second region containing oxygen. In the above embodiment, the second region is thus etched with the deposit formed preferentially on the first region. The technique according to the embodiment allows etching of the second region of the substrate while protecting the first region of the substrate selectively with respect to the second region.
In one exemplary embodiment, the second region may contain silicon nitride. Step (c) may include (c1) forming a different deposit containing a fluorocarbon on the substrate with plasma generated from a second process gas containing a fluorocarbon gas. Step (c) may further include (c2) etching the second region by feeding ions in plasma generated from a noble gas to the substrate on which the different deposit is formed.
In one exemplary embodiment, steps (b) and (c) may be repeated alternately.
In one exemplary embodiment, side and bottom portions of the second region R2 may be surrounded by the first region. The second region may be etched in a self-aligned manner in step (c).
In one exemplary embodiment, the first region may include a photoresist mask on the second region.
In one exemplary embodiment, steps (b) and (c) may be performed in a same chamber.
In one exemplary embodiment, step (b) may be performed in a first chamber, and step (c) may be performed in a second chamber.
In one exemplary embodiment, the etching method may further include a step transporting the substrate from the first chamber to the second chamber through a vacuum between steps (b) and (c).
A plasma processing apparatus according to another exemplary embodiment includes a chamber, a substrate support, a plasma generator, and a controller. The substrate support is accommodated in the chamber. The plasma generator generates plasma in the chamber. The controller performs (a) forming a deposit preferentially on a first region of a substrate with first plasma generated from a first process gas containing carbon and being free of fluorine. The controller further performs (b) etching a second region of the substrate.
In one exemplary embodiment, the controller may further perform (c) repeating steps (a) and (b) alternately.
In one exemplary embodiment, step (b) may be performed in a plurality of cycles. Each of the plurality of cycles includes (b1) forming a different deposit containing a fluorocarbon on the substrate with plasma generated from a second process gas containing a fluorocarbon gas. Each of the plurality of cycles further includes (b2) etching the second region by feeding ions in plasma generated from a noble gas to the substrate on which the different deposit is formed.
In one exemplary embodiment, the first process gas may contain a carbon monoxide gas or a carbonyl sulfide gas.
In one exemplary embodiment, the first process gas may contain a carbon monoxide gas and a hydrogen gas.
In one exemplary embodiment, step (a) may be performed at least when a recess defined by the first region and the second region has an aspect ratio of 4 or lower.
In one exemplary embodiment, the first process gas may contain a first component and a second component. The first component contains carbon and is free of fluorine. The second component contains carbon and fluorine or contains carbon and hydrogen. A flow rate of the first component may be greater than a flow rate of the second component.
In one exemplary embodiment, the plasma processing apparatus may further include an upper electrode above the substrate support. The upper electrode may include a ceiling plate exposed to an internal space of the chamber. The ceiling plate may contain a silicon-containing material.
In one exemplary embodiment, the controller may further perform a step of applying a negative direct-current (DC) voltage to the upper electrode during step (a).
In one exemplary embodiment, the controller may further perform a step of forming the silicon-containing deposit on the substrate after step (a) and before step (b). In one exemplary embodiment, the step of forming a silicon-containing deposit on the substrate may include applying a negative DC voltage to the upper electrode while plasma is being generated in the chamber.
In a substrate processing system for processing a substrate according to still another exemplary embodiment, the substrate includes a first region and a second region. The second region contains silicon and oxygen. The first region contains a material free of oxygen and different from a material for the second region. The substrate processing system includes a deposition apparatus, an etching apparatus, and a transfer module. The deposition apparatus forms a deposit preferentially on the first region with first plasma generated from a first process gas containing carbon and being free of fluorine. The etching apparatus etches the second region. The transfer module transfers the substrate through a vacuum between the deposition apparatus and the etching apparatus.
An etching method according to still another exemplary embodiment includes (a) placing a substrate on a substrate support in a chamber in a plasma processing apparatus. The substrate includes a first region and a second region. The second region contains silicon and oxygen. The first region contains a material free of oxygen and different from a material for the second region. The etching method further includes (b) forming a deposit selectively on the first region with a chemical species fed to the substrate. The chemical species is contained in plasma generated from a process gas containing carbon and being free of fluorine. The etching method further includes (c) etching the second region.
In the above embodiment, a carbon chemical species generated from the process gas is deposited selectively on the first region. The carbon chemical species generated from the process gas is less likely to be deposited on the second region containing oxygen. In the above embodiment, the second region is thus etched while the deposit remains selectively on the first region. The technique according to the embodiment allows etching of the second region of the substrate while protecting the first region of the substrate selectively with respect to the second region.
In one exemplary embodiment, the process gas may be free of hydrogen.
In one exemplary embodiment, the process gas may further contain oxygen. The process gas may contain a carbon monoxide gas or a carbonyl sulfide gas.
In one exemplary embodiment, ions fed to the substrate in step (b) may have an energy value of 0 to 70 eV inclusive.
In one exemplary embodiment, the first region may include silicon nitride.
In one exemplary embodiment, side and bottom portions of the second region R2 may include silicon oxide, and may be surrounded by the first region. The second region may be etched in a self-aligned manner in step (c).
In one exemplary embodiment, the first region as a mask may be located on the second region. The second region may include a silicon-containing film.
In one exemplary embodiment, the plasma processing apparatus may be a capacitively coupled plasma processing apparatus. To generate the plasma, step (b) may include providing radio-frequency power to an upper electrode included in the plasma processing apparatus.
In one exemplary embodiment, the radio-frequency power may have a frequency of 60 MHz or higher.
In one exemplary embodiment, the plasma processing apparatus may be an inductively coupled plasma processing apparatus.
In one exemplary embodiment, steps (b) and (c) may be performed in the plasma processing apparatus without removing the substrate from the chamber.
In one exemplary embodiment, the plasma processing apparatus used in step (b) may be different from an etching apparatus used in step (c). The substrate may be transferred from the plasma processing apparatus used in step (b) to the etching apparatus used in step (c) through a vacuum alone.
In one exemplary embodiment, step (b) may be performed at least when a recess defined by the first region and the second region has an aspect ratio of 4 or lower.
In one exemplary embodiment, steps (b) and (c) may be repeated alternately.
An etching method according to still another exemplary embodiment includes (a) placing a substrate on a substrate support in a chamber in a plasma processing apparatus. The substrate includes a first region and a second region. The second region contains silicon and oxygen. The first region contains a material free of oxygen and different from a material for the second region. The etching method further includes (b) forming a deposit selectively on the first region with a chemical species fed to the substrate. The chemical species is contained in plasma generated from a process gas containing a first gas containing carbon and being free of fluorine and a second gas containing carbon and fluorine or containing carbon and hydrogen. The etching method further includes (c) etching the second region. In step (b), the first gas has a greater flow rate than the second gas.
A plasma processing apparatus according to still another exemplary embodiment includes a chamber, a substrate support, a gas supply unit, a plasma generator, and a controller. The substrate support is accommodated in the chamber. The gas supply unit supplies a gas into the chamber. The plasma generator generates plasma from the gas in the chamber. The controller controls the gas supply unit and the plasma generator. The substrate support supports a substrate including a first region and a second region. The second region contains silicon and oxygen. The first region contains a material free of oxygen and different from a material for the second region. The controller controls the gas supply unit and the plasma generator to generate plasma from a process gas containing carbon and being free of fluorine in the chamber to form a deposit selectively on the first region. The controller controls the gas supply unit and the plasma generator to generate plasma from an etching gas in the chamber to etch the second region.
A substrate processing system according to still another exemplary embodiment includes a plasma processing apparatus, an etching apparatus, and a transfer module. The plasma processing apparatus forms a deposit selectively on a first region of a substrate with a chemical species fed to the substrate. The chemical species is contained in plasma generated from a process gas containing carbon and being free of fluorine. The substrate includes the first region and a second region. The second region contains silicon and oxygen. The first region contains a material free of oxygen and different from a material for the second region. The etching apparatus etches the second region. The transfer module transfers the substrate between the plasma processing apparatus and the etching apparatus through a vacuum alone.
Exemplary embodiments will now be described in detail with reference to the drawings. In the drawings, similar or corresponding components are indicated by like reference numerals.
The substrate W includes a first region R1 and a second region R2. The first region R1 is formed from a material different from a material for the second region R2. The material for the first region R1 may be free of oxygen. The material for the first region R1 may contain silicon nitride. The material for the second region R2 contains silicon and oxygen. The material for the second region R2 may contain silicon oxide. The material for the second region R2 may include a low dielectric constant material containing silicon, carbon, oxygen, and hydrogen.
Steps subsequent to step STa included in the method MT will now be described using an example substrate W shown in
The method MT includes steps STb and STc performed sequentially after step STa. Steps STb and STc may be performed sequentially after steps STa and STc in this order. Step STc may be followed by step STd. Multiple cycles each including steps STb, STc, and STd may be performed sequentially. In other words, steps STb and STc may be repeated alternately. Step STd may be skipped in some of the multiple cycles.
In step STb, a deposit DP is formed selectively or preferentially on the first region R1. In step STb, plasma is generated from a process gas, for example, a first process gas in the chamber in the plasma processing apparatus. The first process gas contains carbon and is free of fluorine. The first process gas contains, as a gas containing carbon and being free of fluorine, for example, a carbon monoxide gas (a CO gas), a carbonyl sulfide gas (a COS gas), or a hydrocarbon gas. The hydrocarbon gas is, for example, a C2H2 gas, a C2H4 gas, a CH4 gas, or a C2H6 gas. The first process gas may be free of hydrogen. The first process gas may further contain a hydrogen gas (an H2 gas) as an additive gas. The first process gas may further contain a noble gas such as an argon gas or a helium gas. The first process gas may further contain an inert gas such as a nitrogen gas (an N2 gas) in addition to or instead of the noble gas. In the first process gas, the flow rate of the gas containing carbon and being free of fluorine may be 30 to 200 sccm inclusive. In the first process gas, the flow rate of the gas containing carbon and being free of fluorine may be 90 to 130 sccm inclusive. In the first process gas, the flow rate of the noble gas may be 0 to 1000 sccm inclusive. In the first process gas, the flow rate of the noble gas may be 350 sccm or less. The flow rate of each gas in the first process gas can be determined by the volume of an internal space 10s in a chamber 10. In step STb, a chemical species (carbon chemical species) contained in the plasma is fed to the substrate. The fed chemical species forms the deposit DP selectively or preferentially on the first region R1 as shown in
In step STb, the first process gas may contain the first gas and the second gas. The first gas contains carbon and is free of fluorine. Examples of such a gas include a CO gas and a COS gas. In other words, the first process gas may contain a first component that contains carbon and is free of fluorine. The first component is, for example, carbon monoxide (CO) or carbonyl sulfide. The second gas contains carbon and fluorine or contains carbon and hydrogen. Examples of such a gas include a hydrofluorocarbon gas, a fluorocarbon gas, and a hydrocarbon gas. In other words, the first process gas may further contain a second component that contains carbon and fluorine or contains carbon and hydrogen. The second component is, for example, hydrofluorocarbon, fluorocarbon, or hydrocarbon. The hydrofluorocarbon gas is, for example, a CHF3 gas, a CH3F gas, or a CH2F2 gas. The fluorocarbon gas is, for example, a C4F6 gas. The second gas containing carbon and hydrogen is, for example, a CH4 gas. The flow rate of the first gas or the first component is greater than that of the second gas or the second component. The ratio of the flow rate of the second gas or the second component to the flow rate of the first gas or the first component may be 0.2 or less. In step STb using the first process gas, a thin protective film is formed on side walls defining the recess in addition to the selective or preferential formation of the deposit DP on the first region R1. The side walls are thus protected from the plasma.
The first process gas used in step STb may be a mixture of a CO gas and a hydrogen gas (an H2 gas). The first process gas allows the deposit DP to form a protective film that is highly resistant to etching in step STc selectively or preferentially on the first region R1. The ratio of the flow rate of the H2 gas to the total flow rate of the CO gas and the H2 gas contained in the first process gas may be 1/19 to 2/17 inclusive. When the first process gas having such a ratio is used, the deposit DP formed on the first region R1 has a side surface with higher verticality.
In step STb, ions fed to the substrate W may have an energy value of 0 to 70 eV inclusive. In this case, the deposit DP is less likely to narrow the opening of the recess.
In one embodiment, the plasma processing apparatus used in step STb may be a capacitively coupled plasma processing apparatus. When a capacitively coupled plasma processing apparatus is used, radio-frequency (RF) power for generating plasma may be provided to an upper electrode. In this case, the plasma can be formed in an area distant from the substrate W. The RF power may have a frequency of 60 MHz or higher. In another embodiment, the plasma processing apparatus used in step STb may be an inductively coupled plasma processing apparatus.
In step STb, the deposit DP can be formed selectively or preferentially on the first region R1. Step STb can thus be performed at least when the recess defined by the first region R1 and the second region R2 of the substrate W has an aspect ratio of 4 or lower.
In subsequent step STc, the second region R2 is etched as shown in
The plasma processing apparatus used in step STb may be used as the etching apparatus used in step STc. In other words, steps STb and STc may be performed in the same chamber. In this case, steps STb and STc are performed without removing the substrate W from the chamber in the plasma processing apparatus. In some embodiments, the plasma processing apparatus used in step STb may be different from the etching apparatus used in step STc. In other words, step STb may be performed in a first chamber, and step STc may be performed in a second chamber. In this case, the substrate W is transferred from the plasma processing apparatus used in step STb to the etching apparatus used in step STc through a vacuum alone between steps STb and STc. In other words, the substrate W is transferred from the first chamber to the second chamber through a vacuum between steps STb and STc.
In subsequent step STd, ashing is performed. In step STd, the deposit DP is removed as shown in
The etching apparatus used in step STc may be used as the ashing apparatus in step STd. In other words, steps STc and STd may be performed in the same chamber. In this case, steps STc and STd are performed without removing the substrate W from the chamber in the etching apparatus. In some embodiments, the etching apparatus used in step STc may be different from the ashing apparatus used in step STd. In other words, the chamber used in step STd may be different from the chamber used in step STc. In this case, the substrate W is transferred from the etching apparatus used in step STc to the ashing apparatus used in step STd through a vacuum alone between steps STc and STd. In other words, the substrate W is transferred from the chamber for step STc to the chamber for step STd through a vacuum between steps STc and STd. The ashing apparatus used in step STd may be the plasma processing apparatus used in step STb.
When multiple cycles are performed sequentially with the method MT, step STJ is then performed. In step STJ, the determination is performed as to whether a stop condition is satisfied. In step STJ, the stop condition is satisfied when the count of the cycles performed reaches a predetermined number. When the stop condition is not satisfied in step STJ, such cycles are restarted. More specifically, step STb is performed again to form a deposit DP on the first region R1 as shown in
The carbon chemical species generated from the first process gas in step STb in the method MT forms a deposit selectively or preferentially on the first region R1. The carbon chemical species generated from the first process gas is less likely to form a deposit on the second region R2 containing oxygen. With the method MT, the second region R2 is etched with the deposit DP formed preferentially on the first region R1. The method MT thus allows the second region R2 to be etched while protecting the first region R1 selectively with respect to the second region R2. With the method MT, the deposit DP is formed selectively or preferentially on the first region R1. This reduces blockage of the opening of the recess defined by the first region R1 and the second region R2.
A carbon chemical species generated from a CO gas in step STb is ionic. A CH4 gas or a CH3F gas tends to generate radicals such as CH2 or CHF. These radicals are highly reactive and easily deposited isotropically on the surface of the substrate W. In contrast, an ionic chemical species is deposited on the substrate W anisotropically. In other words, an ionic chemical species adheres more to the upper surface of the first region R1 than to the wall surfaces defining the recess. Carbon monoxide is likely to be released from the surface of the substrate W. To cause carbon monoxide to be adsorbed on the surface of the substrate W, oxygen is to be removed from the surface of the substrate W with ions striking the surface. In addition, carbon monoxide with a simple structure is difficult to cross-link. To cause carbon monoxide to be deposited on the surface of the substrate W, a dangling bond is to form on the surface of the substrate W. The carbon chemical species generated from the CO gas in step STb is ionic. The chemical species can thus remove oxygen from the upper surface of the first region R1, form a dangling bond on the upper surface, and be deposited selectively on the first region R1.
The plasma processing apparatus 1 is a capacitively coupled plasma processing apparatus. The plasma processing apparatus 1 includes the chamber 10. The chamber 10 has the internal space 10s.
In one embodiment, the chamber 10 may include a chamber body 12. The chamber body 12 is substantially cylindrical. The chamber body 12 has the internal space 10s. The chamber body 12 is formed from a conductor such as aluminum. The chamber body 12 is grounded. The chamber body 12 has an inner wall coated with an anticorrosive film. The anticorrosive film may be formed from ceramic such as aluminum oxide or yttrium oxide.
The chamber body 12 has a side wall having a port 12p. The substrate W is transferred between the internal space 10s and the outside of the chamber 10 through the port 12p. The port 12p can be open and closed by a gate valve 12g. The gate valve 12g is located along the side wall of chamber body 12.
The plasma processing apparatus 1 further includes a substrate support 14. The substrate support 14 supports the substrate W in the chamber 10, or more specifically, in the internal space 10s. The substrate support 14 is accommodated in the chamber 10. The substrate support 14 may be supported by a support 13. The support 13 is formed from an insulating material. The support 13 is substantially cylindrical. The support 13 extends upward from the bottom of the chamber body 12 into the internal space 10s.
In one embodiment, the substrate support 14 may include a lower electrode 18 and an electrostatic chuck (ESC) 20. The substrate support 14 may further include an electrode plate 16. The electrode plate 16 is substantially disk-shaped and is formed from a conductor such as aluminum. The lower electrode 18 is on the electrode plate 16. The lower electrode 18 is formed from a conductor such as aluminum and is substantially disk-shaped. The lower electrode 18 is electrically coupled to the electrode plate 16.
The ESC 20 is on the lower electrode 18. The substrate W is placed on an upper surface of the ESC 20. The ESC 20 has a body formed from a dielectric. The body of the ESC 20 is substantially disk-shaped. The ESC 20 further includes an electrode 20e. The electrode 20e is located in the body of the ESC 20. The electrode 20e is a film electrode. The electrode 20e is coupled to a DC power supply 20p through a switch 20s. A voltage is applied from the DC power supply 20p to the electrode in the ESC 20 to generate an electrostatic attraction between the ESC 20 and the substrate W. The electrostatic attraction causes the ESC 20 to attract and hold the substrate W.
The substrate support 14 may support an edge ring ER placed on it. The edge ring ER may be formed from, but not limited to, silicon, silicon carbide, or quartz. To process the substrate W in the chamber 10, the substrate W is placed in an area on the ESC 20 surrounded by the edge ring ER.
The lower electrode 18 has an internal channel 18f. The channel 18f carries a heat exchange medium (e.g., a refrigerant) supplied from a chiller unit 22 through a pipe 22a. The chiller unit 22 is located outside the chamber 10. The heat-exchange medium being supplied to the channel 18f returns to the chiller unit 22 through a pipe 22b. In the plasma processing apparatus 1, the temperature of the substrate Won the ESC 20 is adjusted through heat exchange between the heat-exchange medium and the lower electrode 18.
The temperature of the substrate W may be adjusted by one or more heaters inside the substrate support 14. Multiple heaters HT are located in the ESC 20 in the example shown in
The plasma processing apparatus 1 may further include a gas supply line 24. The gas supply line 24 supplies a heat-transfer gas (e.g., a He gas) into a space between the upper surface of the ESC 20 and the back surface of the substrate W. The heat-transfer gas is supplied from a heat-transfer gas supply assembly to the gas supply line 24.
The plasma processing apparatus 1 further includes an upper electrode 30. The upper electrode 30 is located above the substrate support 14. The upper electrode 30 is supported on an upper portion of the chamber body 12 with a member 32. The member 32 is formed from an insulating material. The upper electrode 30 and the member 32 close a top opening of the chamber body 12.
The upper electrode 30 may include a ceiling plate 34 and a support member 36. The ceiling plate 34 has its lower surface defining the internal space 10s. In other words, the ceiling plate 34 is exposed to the internal space 10s. The ceiling plate 34 may be formed from a silicon-containing material. The ceiling plate 34 is, for example, formed from silicon or silicon carbide. The ceiling plate 34 has multiple gas holes 34a. The multiple gas holes 34a are through-holes in the thickness direction of the ceiling plate 34.
The support member 36 supports the ceiling plate 34 in a detachable manner. The support member 36 is formed from a conductive material such as aluminum. The support member 36 includes an internal gas-diffusion compartment 36a. The support member 36 further has multiple gas holes 36b. The gas holes 36b extend downward from the gas-diffusion compartment 36a. The gas holes 36b communicate with the respective gas holes 34a. The support member 36 further has a gas inlet 36c. The gas inlet 36c connects to the gas-diffusion compartment 36a. The gas inlet 36c also connects to a gas supply pipe 38.
The gas supply pipe 38 is connected to a set of gas sources 40 with a set of valves 41, a set of flow controllers 42, and a set of valves 43. The gas source set 40, the valve set 41, the flow controller set 42, and the valve set 43 are included in a gas supply unit GS.
The gas source set 40 includes multiple gas sources. When the plasma processing apparatus 1 is used in step STb, the gas sources include one or more gas sources for the first process gas used in step STb. When the plasma processing apparatus 1 is used in step STc, the gas sources include one or more gas sources for the etching gas used in step STc. When the plasma processing apparatus 1 is used in step STd, the gas sources include one or more gas sources for the ashing gas used in step STd.
The valve sets 41 and 43 each include multiple open-close valves. The flow controller set 42 includes multiple flow controllers. The flow controllers in the flow controller set 42 are mass flow controllers or pressure-based flow controllers. The gas sources in the gas source set 40 are connected to the gas supply pipe 38 with the respective open-close valves in the valve set 41, with the respective flow controllers in the flow controller set 42, and with the respective open-close valves in the valve set 43.
The plasma processing apparatus 1 may further include a shield 46. The shield 46 is located along the inner wall of the chamber body 12 in a detachable manner. The shield 46 also extends along the outer periphery of the support 13. The shield 46 prevents byproducts from the plasma processing from accumulating on the chamber body 12. The shield 46 includes, for example, an aluminum member coated with an anticorrosive film. The anticorrosive film may be a film of ceramic such as yttrium oxide.
The plasma processing apparatus 1 may further include a baffle 48. The baffle 48 is located between the support 13 and the side wall of the chamber body 12. The baffle 48 includes, for example, an aluminum plate coated with an anticorrosive film. The anticorrosive film may be a film of ceramic such as yttrium oxide. The baffle 48 has multiple through-holes. The chamber body 12 has an outlet 12e in its bottom below the baffle 48. The outlet 12e is connected to an exhaust device 50 through an exhaust pipe 52. The exhaust device 50 includes a pressure control valve and a vacuum pump such as a turbomolecular pump.
The plasma processing apparatus 1 further includes an RF power supply 62 and a bias power supply 64. The RF power supply 62 generates RF power (hereinafter referred to as RF power HF). The RF power HF has a frequency suitable for generating plasma. The RF power HF has a frequency ranging from, for example, 27 to 100 MHz inclusive. The RF power HF may have a frequency of 60 MHz or higher. The RF power supply 62 is coupled to an RF electrode through a matcher 66. In one embodiment, the RF electrode is the upper electrode 30. The matcher 66 includes a circuit for matching the impedance of a load (the upper electrode 30) for the RF power supply 62 and the output impedance of the RF power supply 62. In one embodiment, the RF power supply 62 may serve as a plasma generator. The RF power supply 62 may be coupled to an electrode in the substrate support 14 (e.g., the lower electrode 18) through the matcher 66. In other words, the RF electrode may be the electrode in the substrate support 14 (e.g., the lower electrode 18).
The bias power supply 64 applies an electrical bias EB to a bias electrode (e.g., the lower electrode 18) in the substrate support 14. The electrical bias EB has a bias frequency suitable for drawing ions toward the substrate W. The electrical bias EB has a bias frequency of, for example, 100 kHz to 40.68 MHz inclusive. When the electrical bias EB is used with the RF power HF, the electrical bias EB has a lower frequency than the RF power HF.
In one embodiment, the electrical bias EB may be RF bias power (hereinafter referred to as RF power LF). The RF power LF has a sinusoidal waveform with a bias frequency. In this embodiment, the bias power supply 64 is coupled to a bias electrode (e.g., the lower electrode 18) through a matcher 68 and the electrode plate 16. The matcher 68 includes a circuit for matching the impedance of a load (the lower electrode 18) for the bias power supply 64 and the output impedance of the bias power supply 64. In another embodiment, the electrical bias EB may be a pulsed voltage. The pulsed voltage may be a pulsed negative voltage. The pulsed negative voltage may be a pulsed negative DC voltage. In this embodiment, a pulsed voltage is periodically applied to the lower electrode 18 at time intervals (e.g., periods) having a time length that is the inverse of the bias frequency.
The plasma processing apparatus 1 further includes a controller MC. The controller MC may be a computer including a processor (such as a CPU that is an example of circuitry that can be configured by software to perform operations according to the software instructions), a storage such as a memory, an input device, a display, and an input-output interface for signals. Alternatively, the controller may include more than one processor, including cloud computer resources, as well as discrete circuitry such application specific integrated circuits (ASIC), programmable logic arrays (PLA), and/or combinations of the examples of discrete and programmable circuitry. The controller MC controls the components of the plasma processing apparatus 1. An operator can use an input device (e.g., user interface such as keyboard, touch panel, and the like) in the controller MC to input a command or perform other operations for managing the plasma processing apparatus 1. The display in the controller MC can display and visualize the operating state of the plasma processing apparatus 1. The storage in the controller MC stores control programs and recipe data. The control program is executed by the processor in the controller MC to perform the processing in the plasma processing apparatus 1. The processor in the controller MC executes the control program to control the components of the plasma processing apparatus 1 in accordance with the recipe data, allowing at least a step or all the steps included in the method MT to be performed by the plasma processing apparatus 1.
The controller MC may perform step STb. When step STb is performed in the plasma processing apparatus 1, the controller MC controls the gas supply unit GS to supply the first process gas into the chamber 10. The controller MC also controls the exhaust device 50 to maintain the chamber 10 at a specified gas pressure. The controller MC also controls the plasma generator to generate plasma from the first process gas in the chamber 10. More specifically, the controller MC controls the RF power supply 62 to provide RF power HF. The controller MC may also control the bias power supply 64 to apply an electrical bias EB.
The controller MC may further perform step STc. When step STc is performed in the plasma processing apparatus 1, the controller MC controls the gas supply unit GS to supply the etching gas into the chamber 10. The controller MC also controls the exhaust device 50 to maintain the chamber 10 at a specified gas pressure. The controller MC also controls the plasma generator to generate plasma from the etching gas in the chamber 10. More specifically, the controller MC controls the RF power supply 62 to provide RF power HF. The controller MC may also control the bias power supply 64 to apply an electrical bias EB.
The controller MC may further perform step STd. When step STd is performed in the plasma processing apparatus 1, the controller MC controls the gas supply unit GS to supply the ashing gas into the chamber 10. The controller MC also controls the exhaust device 50 to maintain the chamber 10 at a specified gas pressure. The controller MC also controls the plasma generator to generate plasma from the ashing gas in the chamber 10. More specifically, the controller MC controls the RF power supply 62 to provide RF power HF. The controller MC may also control the bias power supply 64 to apply an electrical bias EB.
The controller MC may further perform the multiple cycles described above sequentially. The controller MC may further repeat steps STb and STc alternately.
The plasma processing apparatus 1B includes a chamber 110. The chamber 110 has an internal space 110s. In one embodiment, the chamber 110 may include a chamber body 112. The chamber body 112 is substantially cylindrical. The chamber body 112 has the internal space 110s. The chamber body 112 is formed from a conductor such as aluminum. The chamber body 112 is grounded. The chamber body 112 has an inner wall coated with an anticorrosive film. The anticorrosive film may be formed from ceramic such as aluminum oxide or yttrium oxide.
The chamber body 112 has a side wall having a port 112p. The substrate W is transferred between the internal space 110s and the outside of the chamber 110 through the port 112p. The port 112p can be open and closed by a gate valve 112g. The gate valve 112g is located along the side wall of the chamber body 112.
The plasma processing apparatus 1B further includes a substrate support 114. The substrate support 114 supports the substrate W in the chamber 110, or more specifically, in the internal space 110s. The substrate support 114 is accommodated in the chamber 110. The substrate support 114 may be supported by a support 113. The support 113 is formed from an insulating material. The support 113 is substantially cylindrical. The support 113 extends upward from the bottom of the chamber body 112 in the internal space 110s.
In one exemplary embodiment, the substrate support 114 may include a lower electrode 118 and an ESC 120. The substrate support 114 may further include an electrode plate 116. The electrode plate 116 is substantially disk-shaped and is formed from a conductive material such as aluminum. The lower electrode 118 is on the electrode plate 116. The lower electrode 118 is substantially disk-shaped and is formed from a conductive material such as aluminum. The lower electrode 118 is electrically coupled to the electrode plate 116.
The plasma processing apparatus 1B further includes a bias power supply 164. The bias power supply 164 is coupled to a bias electrode (e.g., the lower electrode 118) in the substrate support 114 through a matcher 166. The bias power supply 164 and the matcher 166 are similar to the bias power supply 64 and the matcher 66 in the plasma processing apparatus 1.
The ESC 120 is on the lower electrode 118. The ESC 120 includes a body and an electrode, similarly to the ESC 20 in the plasma processing apparatus 1. The electrode in the ESC 120 is coupled to a DC power supply 120p through a switch 120s. A voltage is applied from the DC power supply 120p to the electrode in the ESC 120 to generate an electrostatic attraction between the ESC 120 and the substrate W. The electrostatic attraction causes the ESC 120 to attract and hold the substrate W.
The lower electrode 118 has an internal channel 118f. The channel 118f carries a heat exchange medium supplied from a chiller unit through a pipe 122a similarly to the channel 18f in the plasma processing apparatus 1. The heat-exchange medium being supplied to the channel 118f returns to the chiller unit through a pipe 122b.
The substrate support 114 may support an edge ring ER placed on it, similarly to the substrate support 14 in the plasma processing apparatus 1. The substrate support 114 may also include one or more heaters HT inside, similarly to the substrate support 14 in the plasma processing apparatus 1. The heater(s) HT is connected to a heater controller HC. The heater controller HC can provide a regulated amount of power to the heater(s) HT.
The plasma processing apparatus 1B may further include a gas supply line 124. The gas supply line 124 supplies a heat-transfer gas (e.g., a He gas) into a space between the upper surface of the ESC 120 and the back surface of the substrate W, similarly to the gas supply line 24 in the plasma processing apparatus 1.
The plasma processing apparatus 1B may further include a shield 146. The shield 146 is similar to the shield 46 in the plasma processing apparatus 1. The shield 146 is located along the inner wall of the chamber body 112 in a detachable manner. The shield 146 also extends along the outer periphery of the support 113.
The plasma processing apparatus 1B may further include a baffle 148. The baffle 148 is similar to the baffle 48 in the plasma processing apparatus 1. The baffle 148 is located between the support 113 and the side wall of the chamber body 112. The chamber body 112 has an outlet 112e in its bottom below the baffle 148. The outlet 112e is connected to an exhaust device 150 through an exhaust pipe 152. The exhaust device 150 includes a pressure control valve and a vacuum pump such as a turbomolecular pump.
The chamber body 112 defines an opening in its top surface. The opening in the top surface of the chamber body 112 is covered with a window 130. The window 130 is formed from a dielectric such as quartz. The window 130 is, for example, plate-shaped. For example, the distance between the lower surface of the window 130 and the upper surface of the substrate W placed on the ESC 120 is set to be 120 to 180 mm.
The chamber 110 or the chamber body 112 has a gas inlet 112i on its side wall. The gas inlet 112i connects to a gas supply unit GSB through a gas supply pipe 138. The gas supply unit GSB includes a set of gas sources 140, a set of flow controllers 142, and a set of valves 143. The gas source set 140, similar to the gas source set 40 in the plasma processing apparatus 1, includes multiple gas sources. The flow controller set 142 is similar to the flow controller set 42 in the plasma processing apparatus 1. The valve set 143 is similar to the valve set 43 in the plasma processing apparatus 1. The gas sources in the gas source set 140 are connected to the gas supply pipe 138 through the respective flow controllers in the flow controller set 142 and with the respective open-close valves in the valve set 143. The gas inlet 112i may be formed in another portion, such as in the window 130, instead of the side wall of the chamber body 112.
The plasma processing apparatus 1B further includes an antenna 151 and a shield 160. The antenna 151 and the shield 160 are located above the top surface of the chamber 110 and above the window 130. The antenna 151 and the shield 160 are outside the chamber 110. In one embodiment, the antenna 151 includes inner antenna elements 153a and outer antenna elements 153b. Each inner antenna element 153a is a spiral coil extending across a middle portion of the window 130. Each outer antenna element 153b is a spiral coil extending above the window 130 and outside the corresponding inner antenna element 153a. The inner antenna element 153a and the outer antenna element 153b are formed from a conductor such as copper, aluminum, or stainless steel.
The plasma processing apparatus 1B may further include multiple clamps 154. Both the inner antenna elements 153a and the outer antenna elements 153b are held between and supported by the clamps 154. The clamps 154 are rod-shaped. The clamps 154 extend radially from around the center of the inner antenna elements 153a to outside the outer antenna elements 153b.
The shield 160 covers the antenna 151. The shield 160 has an inner shield wall 162a and an outer shield wall 162b. The inner shield wall 162a is cylindrical. The inner shield wall 162a is between the inner antenna elements 153a and the outer antenna elements 153b to surround the inner antenna elements 153a. The outer shield wall 162b is cylindrical. The outer shield wall 162b is outside the outer antenna elements 153b to surround the outer antenna elements 153b.
The shield 160 further includes an inner shield plate 163a and an outer shield plate 163b. The inner shield plate 163a is disk-shaped and is located above the inner antenna elements 153a to cover an opening of the inner shield wall 162a. The outer shield plate 163b is annular and is located above the outer antenna elements 153b to cover an opening between the inner shield wall 162a and the outer shield wall 162b.
The shield wall and the shield plate of the shield 160 may have any shapes other than the shapes described above. The shield wall of the shield 160 may have another shape, such as a prism.
The plasma processing apparatus 1B further includes an RF power supply 170a and an RF power supply 170b. The RF power supply 170a and the RF power supply 170b serve as a plasma generator. The RF power supply 170a is coupled to the inner antenna elements 153a, and the RF power supply 170b is coupled to the outer antenna elements 153b. The RF power supply 170a and the RF power supply 170b provide RF power having the same or different frequencies to the inner antenna elements 153a and to the outer antenna elements 153b, respectively. The RF power provided from the RF power supply 170a to the inner antenna elements 153a generates a magnetic induction field in the internal space 110s, causing the gas in the internal space 110s to be excited by the magnetic induction field. This generates plasma above a middle portion of the substrate W. The RF power provided from the RF power supply 170b to the outer antenna elements 153b generates a magnetic induction field in the internal space 110s, causing the gas in the internal space 110s to be excited by the magnetic induction field. This generates annular plasma above a peripheral portion of the substrate W.
The inner antenna elements 153a and the outer antenna elements 153b may have their electrical lengths adjusted in accordance with the RF power output from the respective RF power supplies 170a and 170b. The inner shield plate 163a and the outer shield plate 163b may be adjustable by actuators 168a and 168b to be positioned differently in the height direction.
The plasma processing apparatus 1B further includes a controller MC. The controller MC in the plasma processing apparatus 1B is similar to the controller MC (as well as the various embodiments, as described) in the plasma processing apparatus 1. The controller MC controls the components of the plasma processing apparatus 1B to allow at least a step or all the steps included in the method MT to be performed by the plasma processing apparatus 1B.
The controller MC may perform step STb. When step STb is performed in the plasma processing apparatus 1B, the controller MC controls the gas supply unit GSB to supply the first process gas into the chamber 110. The controller MC also controls the exhaust device 150 to maintain the chamber 110 at a specified gas pressure. The controller MC also controls the plasma generator to generate plasma from the first process gas in the chamber 110. More specifically, the controller MC controls the RF power supply 170a and the RF power supply 170b to provide RF power. The controller MC may also control the bias power supply 164 to apply an electrical bias EB.
The controller MC may further perform step STc. When step STc is performed in the plasma processing apparatus 1B, the controller MC controls the gas supply unit GSB to supply the etching gas into the chamber 110. The controller MC also controls the exhaust device 150 to maintain the chamber 110 at a specified gas pressure. The controller MC also controls the plasma generator to generate plasma from the etching gas in the chamber 110. More specifically, the controller MC controls the RF power supply 170a and the RF power supply 170b to provide RF power. The controller MC may also control the bias power supply 164 to apply an electrical bias EB.
The controller MC may further perform step STd. When step STd is performed in the plasma processing apparatus 1B, the controller MC controls the gas supply unit GSB to supply the ashing gas into the chamber 110. The controller MC also controls the exhaust device 150 to maintain the chamber 110 at a specified gas pressure. The controller MC also controls the plasma generator to generate plasma from the ashing gas in the chamber 110. More specifically, the controller MC controls the RF power supply 170a and the RF power supply 170b to provide RF power. The controller MC may also control the bias power supply 164 to supply an electrical bias EB.
In the plasma processing apparatus 1B, the controller MC may further perform the multiple cycles described above sequentially. The controller MC may further repeat steps STb and STc alternately.
The tables 2a to 2d are arranged along one edge of the loader module LM. The containers 4a to 4d are mounted on the respective tables 2a to 2d. The containers 4a to 4d each are a container called a front-opening unified pod (FOUP). The containers 4a to 4d store substrates W.
The loader module LM includes a chamber. The chamber in the loader module LM has an atmospheric pressure. The loader module LM includes a transfer unit TU1. The transfer unit TU1 may be, for example, a transfer robot controlled by the controller MC. The transfer unit TU1 transfers a substrate W through the chamber in the loader module LM. The transfer unit TU1 may transfer the substrate W between the containers 4a to 4d and the aligner AN, between the aligner AN and the loadlock modules LL1 and LL2, and between the loadlock modules LL1 and LL2 and the containers 4a to 4d. The aligner AN is connected to the loader module LM. The aligner AN adjusts the position of the substrate W (position calibration).
The loadlock modules LL1 and LL2 are located between the loader module LM and the transfer module TM. The loadlock modules LL1 and LL2 each serve as a preliminary decompression chamber.
The transfer module TM is connected to the loadlock modules LL1 and LL2 with the corresponding gate valves. The transfer module TM includes a transfer chamber TC having a decompressible (controllable atmospheric pressure that can be controllably lowered to below atmospheric pressure) internal space. The transfer module TM includes a transfer unit TU2. The transfer unit TU2 is, for example, a transfer robot controlled by the controller MC. The transfer unit TU2 transfers the substrate W through the transfer chamber TC. The transfer unit TU2 may transfer the substrate W between the loadlock modules LL1 and LL2 and the process modules PM1 to PM6, and between any two of the process modules PM1 to PM6.
The process modules PM1 to PM6 are apparatuses dedicated to intended substrate processing. One of the process modules PM1 to PM6 is a plasma processing apparatus such as the plasma processing apparatus 1 or the plasma processing apparatus 1B, which is used in step STb. The process module in the substrate processing system PS used in step STb may also be used in step STd.
Another one of the process modules PM1 to PM6 is an etching apparatus used in step STc. The process module used in step STc may be similar to the plasma processing apparatus 1 or the plasma processing apparatus 1B. The process module in the substrate processing system PS used in step STc may also be used in step STd.
Still another one of the process modules PM1 to PM6 may be an ashing apparatus used in step STd. The process module used in step STd may be similar to the plasma processing apparatus 1 or the plasma processing apparatus 1B.
The controller MC controls the components of the substrate processing system PS. The controller MC may be a computer including a processor, a storage, an input device, and a display. The controller MC executes a control program stored in the storage to control the components of the substrate processing system PS in accordance with recipe data stored in the storage. The method MT is performed using the substrate processing system PS in which the controller MC controls the components of the substrate processing system PS.
When the method MT is performed using the substrate processing system PS, the controller MC controls the process module for step STb, or the plasma processing apparatus or a deposition apparatus, to cause the chemical species contained in the plasma to be fed to the substrate W to form the deposit DP selectively or preferentially on the first region R1.
When step STb and step STc are performed in different process modules, the controller MC controls the transfer module TM to transfer the substrate W through the transfer chamber TC from the process module for step STb to the process module for step STc. The substrate W is thus transported from the chamber (the first chamber) in the process module for step STb to the chamber (the second chamber) in the process module for step STc through a vacuum alone. In other words, the substrate W is transferred from the first chamber to the second chamber through a vacuum between steps STb and STc. When steps STb and STc are performed in the same process module, the substrate W remains in the chamber in the process module.
The controller MC then controls the process module for step STc, or the etching apparatus, to etch the second region R2.
When steps STc and STd are performed in different process modules, the controller MC controls the transfer module TM to transfer the substrate W through the transfer chamber TC from the chamber in the process module for step STc to the chamber in the process module for step STd. The substrate W is thus transferred from the chamber in the process module for step STc to the chamber in the process module for step STd through a vacuum alone. In other words, the substrate W is transferred from the chamber for step STc to the chamber for step STd through a vacuum between steps STc and STd. When step STc and step STd are performed in the same process module, the substrate W remains in the process module.
The controller MC then controls the process module for step STd, or the ashing apparatus to remove the deposit DP.
Various experiments conducted for evaluating the method MT will now be described. The experiments described below are not intended to limit the present disclosure.
In a first experiment and a first comparative experiment, sample substrates SW were prepared. Each sample substrate SW includes a first region R1 and a second region R2 defining a recess RC (refer to
In a second experiment and a second comparative experiment, sample substrates SW were prepared. Each prepared sample substrate SW includes a first region R1 and a second region R2 defining a recess RC. The first region R1 is formed from silicon nitride, and the second region R2 is formed from silicon oxide. The prepared sample substrates each have a recess RC having a lower aspect ratio than the recesses RC in the sample substrates used in the first experiment and the first comparative experiment. More specifically, the sample substrate SW in the second experiment has the recess RC having a width of 12 nm and a depth of 7 nm with its aspect ratio of about 0.6. The sample substrate SW in the second comparative experiment has the recess RC having a width of 12 nm and a depth of 9 nm with its aspect ratio of about 0.8. In the second experiment, a deposit DP was formed on the sample substrate SW under the same conditions as in the first experiment. In the second comparative experiment, a deposit DP was formed on the sample substrate SW under the same conditions as in the first comparative experiment.
In a third experiment, multiple sample substrates SW with the same structure as the sample substrate used in the first experiment were prepared. In the third experiment, deposits DP were formed on the sample substrates SW using a mixture of a CO gas and an Ar gas as a first process gas in the plasma processing apparatus 1. In the third experiment, the deposits DP were formed on the sample substrates SW using ions with different amounts of energy (in other words, ion energy) for different sample substrates SW. In the third experiment, the ion energy was adjusted by changing the power level of the RF power LF. The other conditions in the third experiment are the same as the corresponding conditions in the first experiment. In the third experiment, the widths of the opening of the recesses RC in the sample substrates SW were determined after the deposits DP were formed. The relationship between the ion energy and the width of the opening was then obtained. The results are shown in the graph in
In fourth to sixth experiments, sample substrates with the same structure as the sample substrate used in the first experiment were prepared. Deposits DP were formed on the sample substrates and then the second regions R2 were etched using the plasma processing apparatus 1. In the fourth experiment, a mixture of a CO gas and an Ar gas was used as the first process gas to form the deposit DP. In the fifth experiment, a mixture of a CO gas and a CH4 gas was used as the first process gas to form the deposit DP. In the sixth experiment, a mixture of a CO gas and an H2 gas was used as a first process gas to form the deposit DP. The other conditions for forming the deposit DP in each of the fourth to sixth experiments are the same as the conditions in the first experiment. The second regions R2 were etched in the fourth to sixth experiments under the conditions provided below.
The measured film thickness TB is 1.8 nm, 3.0 nm, and 1.6 nm respectively in the fourth to sixth experiments. In other words, the deposit DP formed with the mixture of a CO gas and an Ar gas or the mixture of a CO gas and an H2 gas as the first process gas has, at the bottom of the recess, a smaller film thickness than the deposit DP formed with the first process gas containing a CH4 gas. The increase in the measured depths Ds of the recess is 1.0 nm, 0.5 nm, and 0.9 nm respectively in the fourth to sixth experiments. In other words, with the first process gas containing the mixture of a CO gas and an Ar gas or the mixture of a CO gas and an H2 gas, the second region R2 was etched more at the bottom of the recess than with the first process gas containing a CH4 gas. The decrease in the measured film thicknesses TT is 3.5 nm, 1.7 nm, and 1.2 nm respectively in the fourth to sixth experiments. In other words, with the first process gas containing the mixture of a CO gas and an H2 gas for forming the deposit DP, a decrease in a measured film thickness TT is far less than with the first process gas containing another process gas. This reveals that a protective film highly resistive to etching of the second region R2 can be formed selectively or preferentially on the first region R1 using the mixture of a CO gas and an H2 gas as the first process gas.
In seventh to twelfth experiments, sample substrates with the same structure as the sample substrate used in the first experiment were prepared. Deposits DP were formed on the sample substrates using the plasma processing apparatus 1. In the seventh to twelfth experiments, a process gas used for forming the deposit DP contains a CO gas and an Ar gas. In the eighth to twelfth experiments, a first process gas used for forming the deposit DP further contains an H2 gas. The ratio of the flow rate of the H2 gas to the total flow rate of the CO gas and the H2 gas contained in the first process gas is 0, 1/19, 4/49, 2/17, ΒΌ, and 5/14 respectively in the seventh to twelfth experiments. The other conditions for forming the deposit DP in each of the seventh to twelfth experiments are the same as the conditions in the first experiment.
Step STc shown in
In step STc2, ions contained in a noble gas are fed to the substrate W to etch the second region R2. In step STc2, plasma is generated from the noble gas in the chamber in the etching apparatus. The noble gas used in step STc2 is, for example, an Ar gas. The noble gas used in step STc2 may be a noble gas other than an Ar gas. In step STc2, ions in the noble gas contained in the plasma are fed to the substrate W. The ions in the noble gas fed to the substrate W cause the fluorocarbon contained in the deposit DPC to react with the material for the second region R2. In step STc2, the second region R2 is thus etched as shown in
In step STc shown in
Step STc may be followed by step STd. In some embodiments, step STc may be followed by step STJ, without step STd. In step STJ, the determination may be performed as to whether a stop condition is satisfied. When the stop condition is not satisfied in step STJ, step STb is restarted. In step STb, the deposit DP is formed on the deposit DPC on the first region R1 as shown in
In step STc shown in
The etching apparatus used in step STc shown in
In step STc2, the controller MC in the plasma processing apparatus 1 controls the gas supply unit GS to supply a noble gas into the chamber 10. In step STc2, the controller MC controls the exhaust device 50 to maintain the chamber 10 at a specified gas pressure. In step STc2, the controller MC also controls the plasma generator to generate plasma from the noble gas in the chamber 10. More specifically, the controller MC controls the RF power supply 62 to provide RF power HF. In step STc2, the controller MC also controls the bias power supply 64 to apply an electrical bias EB.
When the etching apparatus used in step STc shown in
In step STc2, the controller MC in the plasma processing apparatus 1B controls the gas supply unit GSB to supply a noble gas into the chamber 110. In step STc2, the controller MC controls the exhaust device 150 to maintain the chamber 110 at a specified gas pressure. In step STc2, the controller MC also controls the plasma generator to generate plasma from the noble gas in the chamber 110. More specifically, the controller MC controls the RF power supply 170a and the RF power supply 170b to provide RF power. In step STc2, the controller MC also controls the bias power supply 164 to apply an electrical bias EB.
An etching method according to another exemplary embodiment will now be described with reference to
The method MTB may be implemented with the plasma processing apparatus 1 or the plasma processing apparatus 1B. The method MTB may be implemented with a different plasma processing apparatus.
The plasma processing apparatus 1C includes at least one DC power supply. The DC power supply applies a negative DC voltage to the upper electrode 30. When a negative DC voltage is applied to the upper electrode 30 while plasma is being generated in the chamber 10, positive ions in the plasma strike the ceiling plate 34. Secondary electrons are then emitted from the ceiling plate 34 and fed to the substrate. Silicon is also released from the ceiling plate 34 and fed to the substrate.
In one embodiment, the upper electrode 30 may include an inner portion 301 and an outer portion 302. The inner portions 301 and the outer portion 302 are electrically isolated from each other. The outer portion 302 is located radially outside the inner portion 301 and extends circumferentially to surround the inner portion 301. The inner portion 301 includes an inner region 341 of the ceiling plate 34, and the outer portion 302 includes an outer region 342 of the ceiling plate 34. The inner region 341 may be substantially disk-shaped, and the outer region 342 may be annular. Each of the inner and outer regions 341 and 342 is formed from a silicon-containing material similarly to the ceiling plate 34 in the plasma processing apparatus 1.
In the plasma processing apparatus 1C, an RF power supply 62 supplies RF power HF to both the inner portions 301 and the outer portion 302. The plasma processing apparatus 1 may include a DC power supply 71 and a DC power supply 72 as the at least one DC power supply. Each of the DC power supplies 71 and 72 may be a variable DC power supply. The DC power supply 71 is electrically coupled to the inner portion 301 to apply a negative DC voltage to the inner portion 301. The DC power supply 72 is electrically coupled to the outer portion 302 to apply a negative DC voltage to the outer portion 302. The other structures of the plasma processing apparatus 1C may be the same as the corresponding structures of the plasma processing apparatus 1.
Referring back to
The method MTB starts from step STa. Step STa in the method MTB is the same as step STa in the method MT.
Step STe follows step STa. In step STe, a first deposit DP1 is formed selectively or preferentially on the first region R1 as shown in
In one embodiment, step STe may be the same as step STb. In this case, the first deposit DP1 formed in step STe is the same as the deposit DP. In this case, the plasma processing apparatus used in step STe may be the plasma processing apparatus 1, 1B, or 1C.
In another embodiment, step STe may include applying a negative DC voltage to the upper electrode 30 while the same processing as in step STb is being performed. In this case, the plasma processing apparatus 1C is used in step STe. In this case, the first deposit DP1 is a dense film formed from a chemical species (e.g., carbon) contained in plasma generated from the first process gas and silicon released from the ceiling plate 34. In this case, the controller MC in the plasma processing apparatus 1C further performs applying a negative DC voltage to the upper electrode 30 while step STb is being performed.
In step STe, the controller MC controls the at least one DC power supply to apply a negative DC voltage to the upper electrode 30. More specifically, the controller MC controls the DC power supplies 71 and 72 to apply a negative DC voltage to the upper electrode 30. The negative DC voltage applied from the DC power supply 71 to the inner portion 301 of the upper electrode 30 may have a greater absolute value than the negative DC voltage applied from the DC power supply 72 to the outer portion 302 of the upper electrode 30. In step STe, the DC power supply 72 may not apply a voltage to the outer portion 302 of the upper electrode 30.
As described above, the method MTB may further include step STf. Step STf is performed after step STe and before step STc. In step STf, a second deposit DP2 is formed on the substrate W as shown in
In step STf, the second deposit DP2 may be formed by plasma-enhanced chemical vapor deposition (PECVD). When the second deposit DP2 is formed by PECVD, the plasma processing apparatus used in step STf may be the plasma processing apparatus 1, 1B, or 1C.
When PECVD is performed using the plasma processing apparatus 1 or 1C in step STf, the controller MC controls the gas supply unit GS to supply the process gas into the chamber 10. The process gas contains a silicon-containing gas such as an SiCl4 gas. The process gas may further contain an H2 gas. The controller MC also controls the exhaust device 50 to maintain the chamber 10 at a specified gas pressure. The controller MC also controls the plasma generator to generate plasma from the process gas in the chamber 10. More specifically, the controller MC controls the RF power supply 62 to provide RF power HF.
When PECVD is performed using the plasma processing apparatus 1B in step STf, the controller MC controls the gas supply unit GSB to supply the process gas into the chamber 110. The process gas contains a silicon-containing gas such as an SiCl4 gas. The process gas may further contain an H2 gas. The controller MC also controls the exhaust device 150 to maintain the chamber 110 at a specified gas pressure. The controller MC also controls the plasma generator to generate plasma from the process gas in the chamber 110. More specifically, the controller MC controls the RF power supply 170a and the RF power supply 170b to provide RF power.
In some embodiments, step STf may include applying a negative DC voltage to the upper electrode 30 while plasma is being generated in the chamber 10. When a negative DC voltage is applied to the upper electrode 30 while plasma is being generated in the chamber 10, positive ions in the plasma strike the ceiling plate 34. Secondary electrons are thus emitted from the ceiling plate 34 and fed to the substrate W. Silicon is also released from the ceiling plate 34 and fed to the substrate W. The silicon fed to the substrate W forms the second deposit DP2 on the substrate W. In this case, the plasma processing apparatus 1C is used in step STf.
The controller MC in the plasma processing apparatus 1C performs step STf. In step STf, the controller MC controls the gas supply unit GS to supply a gas into the chamber 10. The gas supplied to the chamber 10 in step STf contains a noble gas such as an Ar gas. The gas supplied to the chamber 10 in step STf may further contain a hydrogen gas (an H2 gas). The controller MC also controls the exhaust device 50 to maintain the chamber 10 at a specified gas pressure. The controller MC also controls the plasma generator to generate plasma from a gas in the chamber 10. More specifically, the controller MC controls the RF power supply 62 to provide RF power HF.
In step STf, the controller MC controls the at least one DC power supply to apply a negative DC voltage to the upper electrode 30. More specifically, the controller MC controls the DC power supplies 71 and 72 to apply a negative DC voltage to the upper electrode 30. The negative DC voltage applied from the DC power supply 71 to the inner portion 301 of the upper electrode 30 may have a greater absolute value than the negative DC voltage applied from the DC power supply 72 to the outer portion 302 of the upper electrode 30.
With the method MTB, step STc is then performed to etch the second region R2 as shown in
With the method MTB, after the second region R2 is etched, step STd may be performed to remove the first deposit DP1 and the second deposit DP2 as shown in
With the method MTB, the second deposit DP2 is formed on the first deposit DP1 to further reduce the likelihood of etching of the corner of the first region R1 of the substrate W and to reduce the likelihood of enlarging the opening of the recess defined by the first region R1.
As described above, the method MT may perform multiple cycles each including steps STe, STf, STc, and STd. In some of the multiple cycles, at least one of steps STe, STf, and STd may be eliminated. The number of cycles including step STe may be less than the number of cycles including step STf. In this case, the count of step STe can be reduced by performing step STf to form the second deposit DP2 before the first deposit DP1 is consumed.
The substrate WC includes a first region R1 and a second region R2. The substrate WC may further include a third region R3 and an underlying region UR. The third region R3 is formed on the underlying region UR. The third region R3 is formed from an organic material. The second region R2 is formed on the third region R3. The second region R2 contains silicon oxide. The second region R2 may include a silicon oxide film and a silicon carbide film on the silicon oxide film. The first region R1 is a mask formed on the second region R2 and is patterned. The second region R2 may be a photoresist mask. The second region R2 may be an extreme ultraviolet (EUV) mask.
Although the various exemplary embodiments have been described above, various additions, omissions, substitutions, and modifications may be made without limitation to the exemplary embodiments described above. The components in the different exemplary embodiments may be combined to form another exemplary embodiment.
The plasma processing apparatus used with the methods MT and MTB may be a capacitively coupled plasma processing apparatus different from the plasma processing apparatus 1. The plasma processing apparatus used with the methods MT and MTB may be an inductively coupled plasma processing apparatus different from the plasma processing apparatus 1B. The plasma processing apparatus used with the methods MT and MTB may be any type of plasma processing apparatus. Examples of such a plasma processing apparatus include an electron cyclotron resonance (ECR) plasma processing apparatus and a plasma processing apparatus that generates plasma using surface waves such as microwaves.
The exemplary embodiments according to the present disclosure have been described by way of example, and various changes may be made without departing from the scope and spirit of the present disclosure. The exemplary embodiments disclosed above are thus not restrictive, and the true scope and spirit of the present disclosure are defined by the appended claims.
Number | Date | Country | Kind |
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2020-157290 | Sep 2020 | JP | national |
2020-185206 | Nov 2020 | JP | national |
2021-029988 | Feb 2021 | JP | national |
The present application is a Continuation-in-Part of International Application PCT/JP2021/031030, filed Aug. 24, 2021, which claims priorities to Japanese Application No. 2020-157290, filed Sep. 18, 2020, Japanese Application No. 2020-185206, filed Nov. 5, 2020, Japanese Application No. 2021-029988, filed Feb. 26, 2021, and claims the benefit of U.S. Provisional Patent Application No. 63/162,739, filed Mar. 18, 2021, the entire contents of each are incorporated herein by reference.
Number | Date | Country | |
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63162739 | Mar 2021 | US |
Number | Date | Country | |
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Parent | PCT/JP2021/031030 | Aug 2021 | US |
Child | 17865433 | US |