Patent Application
20240274433
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2022-137232, filed on Aug. 30, 2022, the entire contents of which are incorporated herein by reference.
The present disclosure relates to a substrate processing method and a substrate processing apparatus.
Patent Document 1 discloses a method of manufacturing semiconductor devices. The method forms a film in a trench formed in a surface of a substrate by performing: a process of repeating a predetermined number of times a cycle in which an operation of supplying a halogen-based raw material gas to the substrate, an operation of supplying a reactive gas to the substrate, and an operation of supplying a reaction-inhibiting gas to the substrate under a first process condition are performed in a time division manner; and a process of repeating a predetermined number of times a cycle in which an operation of supplying the halogen-based raw material gas to the substrate, an operation of supplying the reactive gas to the substrate, and an operation of supplying the reaction-inhibiting gas to the substrate under a second process condition different from the first process condition are performed in a time division manner.
According to one embodiment of the present disclosure, there is provided a substrate processing method of embedding a silicon nitride film in a recess formed in a surface of a substrate, the method including: repeating a cycle, the cycle including: a first operation of supplying a silicon precursor to form an adsorption layer of the silicon precursor on the substrate; a second operation of supplying a first nitrogen-containing gas and supplying a first power to an upper electrode to generate a first plasma, and exposing the substrate to the first plasma to nitride the adsorption layer and form the silicon nitride film; and a third operation of supplying a second nitrogen-containing gas and supplying a second power to a lower electrode to generate a second plasma different from the first plasma, and exposing the substrate to the second plasma to modify an upper portion of the recess and form an adsorption-inhibiting area.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.
Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same reference numerals will be given to the same components, and redundant descriptions thereof will be omitted. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments.
A plasma processing apparatus (substrate processing apparatus) 100 according to the present embodiment will be described with reference to
As illustrated in
The plasma processing apparatus 100 includes the processing container 1 having an upper opening, a lid 1L that seals the upper opening of the processing container 1, the stage 2 (lower electrode) arranged inside the processing container 1, and a plasma generating source located above the stage 2. The plasma generating source includes the upper electrode 3 arranged to face the stage 2 and the dielectric cylinder 4 having an electromagnetic-wave radiation port (radio-frequency radiation port). Electromagnetic waves are radiated from a lower end face of the dielectric cylinder 4. The dielectric cylinder 4 is an introducer through which the electromagnetic wave (radio frequency) is introduced.
A processing target (substrate W) is placed on the stage 2. The substrate W is not particularly limited as long as it is subjected to a plasma processing, but examples of the substrate W may include a semiconductor substrate, an insulator substrate such as glass or alumina (Al2O3), and a metal substrate.
The first power supplier 5 supplies radio-frequency (RF) power to the processing container 1. The first power supplier 5 includes a first power supply 51, a first matcher 52, an antenna 53, and a waveguide 54. The first power supply 51 may be a power supply that generates RF power in a very high frequency (VHF) band. The RF power generated by the first power supply 51 has a frequency suitable for plasma generation. A frequency of the RF power supplied to the upper electrode 3 by the first power supply 51 may be 100 MHz or higher, specifically 220 MHz. The first power supply 51 is connected to the antenna 53 via the first matcher 52. The first matcher 52 includes a circuit for matching an output reactance of the first power supply 51 with a load reactance. The waveguide 54 is formed between the upper electrode 3, a lower surface of the lid 1L, and an inner surface of the processing container 1. The electromagnetic waves (for example, electromagnetic waves having a frequency higher than that of shortwaves such as VHF waves and UHF waves), which are input from the first power supply 51 to an upper portion of the upper electrode 3 via the first matcher 52 and the antenna 53, propagate radially and horizontally through the waveguide 54. When these electromagnetic waves hit the inner surface of the processing container 1, they propagate downward, and pass through the dielectric cylinder 4 to be emitted from a lower end surface thereof.
In a state in which a processing gas is introduced into the processing container 1 and the interior of the processing container 1 is depressurized by the exhaust device 8, which will be described later, to a pressure at which plasma generation is possible, when the electromagnetic waves are introduced into the processing container 1 from the first power supplier 5, plasma is generated below the upper electrode 3. A plasma area is located directly beneath the upper electrode 3. In addition, one end of the first power supply 51 is connected to the first matcher 52, while the other end is connected to a ground. Further, the antenna 53 may be any antenna capable of transmitting electromagnetic waves such as VHF waves may be employed, and as an electromagnetic-wave transmission component, a coaxial cable may be employed in addition to the waveguide.
The second power supplier 6 applies (supplies) radio-frequency (RF) power to the stage 2 serving as a lower electrode. The second power supplier 6 includes a second power supply 61 and a second matcher 62. The second power supply 61 may be a power supply that generates RF power in a medium frequency (MF) band or in a high frequency (HF) band. The RF power generated by the second power supply 61 has a frequency suitable for plasma generation. A frequency of the RF power supplied to the lower electrode (stage 2) by the second power supply 61 may fall within a range from 300 MHz to 30 MHz, specifically 13.56 MHz. The second power supply 61 is connected to the stage 2, which serves as the lower electrode, via the second matcher 62. The second matcher 62 includes a circuit for matching an output reactance of the second power supply 61 with a load reactance.
In a state in which a processing gas is introduced into the processing container 1 and the interior of the processing container 1 is depressurized by the exhaust device 8, which will be described later, to a pressure at which plasma generation is possible, when the RF power is applied (supplied) from the second power supplier 6 to the stage 2 serving as the lower electrode, a capacitively coupled plasma (CCP) is generated between the upper electrode 3 and the lower electrode (stage 2).
The gas supplier 7 supplies the processing gas into the processing container 1. The gas supplier 7 includes a gas source 71 and a supply pipe 72. The gas source 71 supplies the processing gas into the processing container 1 via the supply pipe 72. Specifically, the upper electrode 3 has a shower structure in which a processing gas distribution portion (internal space 31) is provided. The supply pipe 72 passes through the lid 1L, crosses the waveguide 54, and is fluidly connected to the internal space 31. The processing gas introduced into the internal space 31 is supplied to the interior of the processing container 1 via a plurality of processing gas ejection ports (gas holes 32) provided in a lower region of the upper electrode 3. The upper electrode 3 of this example takes a structure of a shower plate made of a metal, and includes the internal space 31 into which the processing gas is introduced, and the plurality of gas holes 32 which communicate the internal space 31 with the internal space of the processing container 1. The upper electrode 3 includes an upper metal member 3A having a recess on a lower surface thereof and a lower metal member 3B having the plurality of gas holes 32, and the internal space 31 is formed at the position of the recess between these metal members.
The exhaust device 8 exhausts the interior of the processing container 1. The exhaust device 8 exhausts the gas inside the processing container 1 to the outside via a gas exhaust port 11 of the processing container 1.
The controller 9 is, for example, a computer, and includes a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), an auxiliary storage device, and the like. The CPU operates based on programs stored in the ROM or the auxiliary storage device which may be a non-transitory computer-readable storage medium, and controls the operation of the plasma processing apparatus 100. The controller 9 may be provided inside or outside the plasma processing apparatus 100. When the controller 9 is provided outside the plasma processing apparatus 100, the controller 9 may control the plasma processing apparatus 100 by a communication means based on, for example, a wired or wireless manner.
Next, an example of a SiN film formation process using the plasma processing apparatus 100 will be described with reference to
The PE-ALD process according to the present embodiment illustrated in
Operation S101 performing the purging is an operation of purging gases and the like in a processing space of the processing container 1. In Operation S101 performing the purging, the controller 9 controls the gas supplier 7 to supply the N2 gas from the gas source 71 into the processing space of the processing container 1 at a first flow rate and to supply the Ar gas as the inert gas at a second flow rate. Further, the controller 9 controls the exhaust device 8 to control an internal pressure of the processing space of the processing container 1 to a first pressure. Thus, the gases and like in the processing space of the processing container 1 are purged.
Operation S102 supplying the silicon raw material gas is an operation of supplying the silicon precursor gas (for example, DCS gas) into the processing space of the processing container 1. In Operation S102 supplying the silicon precursor gas, the controller 9 controls the gas supplier 7 to supply the silicon precursor gas from the gas source 71 into the processing space of the processing container 1. The silicon precursor is selected from at least one of halogenated silane, aminosilane, silylamine, and the like. In addition, in the following, descriptions will be made under the assumption that the dichlorosilane (DCS) gas is used as as the silicon precursor gas. Further, subsequent to Operation S101 performing the purging, the controller 9 controls the gas supplier 7 to supply the N2 gas as the purge gas from the gas source 71 into the processing space of the processing container 1 at the first flow rate and to supply the Ar gas as the inert gas at the second flow rate. Further, the controller 9 controls the exhaust device 8 to control the internal pressure of the processing space of the processing container 1 to a second pressure. In addition, the second pressure is higher than the first pressure (second pressure>first pressure). Thus, the silicon precursor is adsorbed onto a surface of the substrate W so that an adsorption layer of the silicon precursor is formed on the surface of the substrate W. Specifically, adsorption sites to which the silicon precursor is adsorbed are formed on the surface of the substrate W. As the silicon precursor is adsorbed to the adsorption sites, the adsorption layer of the silicon precursor is formed on the surface of the substrate W.
Further, the internal pressure (second pressure) of the processing space in Operation S102 supplying the silicon precursor gas is higher than the internal pressure (first pressure) of the processing space in each of Operations S101 and S103 to S106. As described above, by increasing the internal pressure of the processing space in Operation S102 supplying the silicon precursor gas, the silicon precursor is properly adsorbed to the surface of the substrate W.
Further, the flow rate (first flow rate) of the N2 gas in Operation S102 supplying the silicon precursor gas is smaller than a flow rate (third flow rate to be described later) of the N2 gas in each of Operations S103 to S106. Further, the flow rate (second flow rate) of the Ar gas in Operation S102 supplying the silicon precursor gas is smaller than a flow rate (fourth flow rate to be described later) of the Ar gas in each of Operations S103 to S106. Further, the sum of the flow rate (first flow rate) of the N2 gas and the flow rate (second flow rate) of the Ar gas in Operation S102 supplying the silicon precursor gas is smaller than the sum of the flow rate (third flow rate to be described later) of the N2 gas and the flow rate (fourth flow rate to be described later) of the Ar gas in each of Operations S103 to S106. As described above, by decreasing the flow rates of the N2 gas and the Ar gas in Operation S102 supplying the silicon precursor gas, a partial pressure of the silicon precursor gas may be increased so that the silicon precursor is properly adsorbed to the surface of the substrate W.
Operation S103 performing the purging is an operation of purging an excess of the silicon precursor gas and the like in the processing space of the processing container 1. In Operation S103 performing the purging, the controller 9 controls the gas supplier 7 to supply the N2 gas from the gas source 71 into the processing space of the processing container 1 at the third flow rate and to supply the Ar gas as the inert gas at the fourth flow rate. In addition, the third flow rate is larger than the first flow rate (third flow rate>first flow rate). The fourth flow rate is larger than the second flow rate (fourth flow rate>second flow rate). Further, the controller 9 controls the exhaust device 8 to control the internal pressure of the processing space of the processing container 1 to the first pressure. Thus, the gases and the like in the processing space of the processing container 1 are purged. Further, in Operation S103 performing the purging, in order to prepare the subsequent Operation S104 performing the nitriding process, the controller 9 controls the gas supplier 7 to supply a first nitrogen-containing gas (a mixed gas of the H2 gas and the N2 gas), which will be described later, from the gas source 71 into the processing space of the processing chamber 1.
Operation S104 performing the nitriding process is an operation of supplying the first nitrogen-containing gas (for example, the mixed gas of the H2 gas and the N2 gas), supplying power to the upper electrode 3 to generate a first plasma, and exposing the substrate W to the first plasma to nitride the adsorption layer of the silicon precursor formed on the surface of the substrate W and form a silicon nitride film. In other words, Operation S104 is an operation of exciting the first nitrogen-containing gas with the first plasma. In addition, the first nitrogen-containing gas is also referred to as a reactive gas that reacts with the silicon precursor, or a nitriding gas that nitrides the silicon precursor. In Operation S104 performing the nitriding process, the controller 9 controls the gas supplier 7 to supply the first nitrogen-containing gas from the gas source 71 into the processing space of the processing container 1. The first nitrogen-containing gas is selected from at least one of a N2 gas, a NH3 gas, and a mixed gas of N2 gas and H2 gas. In addition, in the following, descriptions will be made under the assumption that the mixed gas of the H2 gas and the N2 gas is used as the first nitrogen-containing gas. In other words, subsequent to Operation S103 performing the purging, the controller 9 controls the gas supplier 7 to supply the first nitrogen-containing gas (the mixed gas of the H2 gas and the N2 gas) and the inert gas (Ar gas) from the gas source 71 into the processing space of the processing chamber 1. Further, the controller 9 controls the exhaust device 8 to control the internal pressure of the processing space of the processing container 1 to the first pressure. Further, the controller 9 controls the first power supply 51 to supply the RF power to the antenna 53. Thus, plasma is generated below the upper electrode 3. Thus, the adsorption layer of the silicon precursor on the surface of the substrate W is nitrided by active species (for example, N ions and N radicals) of the first nitrogen-containing gas to form the SiN film. Further, the adsorption sites to which the silicon precursor is adsorbed are formed on the surface of the substrate W. The adsorption sites are, for example, NHx-groups (N—H bonds, where x=1, 2).
Operation S105 performing the purging is an operation of purging an excess of the first nitrogen-containing gas and the like in the processing space of the processing container 1. In Operation S105 performing the purging, the controller 9 controls the gas supplier 7 to supply the N2 gas from the gas source 71 into the processing space of the processing container 1 at the third flow rate and to supply the Ar gas as the inert gas at the fourth flow rate. Further, the controller 9 controls the exhaust device 8 to control the internal pressure of the processing space of the processing container 1 to the first pressure. Thus, the gases and the like in the processing space of the processing container 1 are purged. Further, in Operation S105 performing the purging, in order to prepare the subsequent Operation S106 forming the adsorption-inhibiting area, the controller 9 controls the gas supplier 7 to supply a second nitrogen-containing gas (N2 gas), which will be described later, from the gas source 71 into the processing space of the processing chamber 1.
Operation S106 forming the adsorption-inhibiting area is an operation of supplying the second nitrogen-containing gas (for example, the N2 gas), supplying power to the lower electrode (the stage 2) to generate a second plasma, and exposing the substrate W to the second plasma to modify an upper surface of a recess 601 (see
Further, the controller 9 controls the second power supply 61 to supply the RF power to the stage 2 as the lower electrode. In Operation S106, no plasma is generated by the first power supply 51. Thus, the surface of the substrate W is exposed to a N2 plasma. Further, the surface of the substrate W is exposed to the N2 plasma so that the adsorption-inhibiting area in which adsorption sites of the silicon precursor are reduced is formed.
By repeating the above-described cycle, the SiN film is formed on the substrate W.
In addition, the process of forming the SiN film using the plasma processing apparatus 100 is not limited to that illustration in
Further, when a first cycle is defined to include Operations S101 to S104, the first cycle is repeated a predetermined number of times (for example, 5 times or 10 times), and subsequently, a second cycle including Operations S105 and S106 and returning to Operation S101 again is repeated. In other words, Operations S105 and S106 may be performed each time the first cycle including Operation S101 to Operation S104 is performed the predetermined number of times.
Next, another example of the SiN film formation process using the plasma processing apparatus 100 will be described with reference to
The PE-ALD process according to the present embodiment illustrated in
Here, Operations S201 to S205 illustrated in
Operation S206 forming the adsorption-inhibiting area is an operation of supplying the second nitrogen-containing gas (for example, N2 gas) to generate plasma, thus forming the adsorption-inhibiting area. In Operation S104 performing the nitriding process, the controller 9 controls the gas supplier 7 to supply the second nitrogen-containing gas (N2 gas) and the inert gas (Ar gas) from the gas source 71 into the processing space of the processing chamber 1. Further, the controller 9 controls the exhaust device 8 to control the internal pressure of the processing space of the processing container 1 to the first pressure. Further, the controller 9 controls the first power supply 51 to supply the RF power to the antenna 53.
Next, examples of film formation results of the SiN film formation process according to the present embodiment and the SiN film formation process according to the Reference example will be described with reference to
Here, as illustrated in
Here, in
Further, in the graphs of
The vertical axis in
In Operation S206 forming the adsorption-inhibiting area as indicated by the one-dot dashed lines, as illustrated in the results of the film formation process illustrated in
In contrast, in Operation S106 forming the adsorption-inhibiting area as indicated by the solid lines, as illustrated in the results of the film formation process illustrated in
The vertical axis in
The results of the film formation process illustrated in
As described above, according to the film formation process illustrated in
Thus, by repeating the film formation process illustrated in
Further, as the number of ALD cycles increases, the conditions for generating the second plasma in Operation S106 forming the adsorption-inhibiting area (third operation) are changed in a stepwise manner. Specifically, at least one of the power (RF power) to generate the second plasma, the supply amount of the second nitrogen-containing gas and the exposure time to the second plasma, and the supply amount of the second nitrogen-containing gas and the exposure time to the second plasma are changed (increased or decreased) in a stepwise manner.
In other words, as the number of ALD cycles increases and the embedding of the SiN film 620 progresses from the bottom surface of the recess 601, the aspect ratio of the recess 601 varies. Therefore, the range in which the adsorption-inhibiting area 630 is formed is changed by changing the conditions for generating the second plasma.
Here, when the number of ALD cycles reaches a predetermined number of times, the conditions for generating the second plasma are changed such that the range of the adsorption-inhibiting area 630 formed on the side surface of the recess 601 corresponds to only a shallower portion of the recess 601. Thus, as illustrated in
Specifically, changing the condition for generating the second plasma may reduce the power (RF power) of the second plasma. Further, the supply amount of the second nitrogen-containing gas may be reduced. Further, the irradiation time (exposure time) to the second plasma may be reduced. Further, at least 2 or more of these may be combined with each other.
Thereafter, the condition for generating the second plasma may be changed in a stepwise manner each time the number of ALD cycles reaches a predetermined number of times.
Thus, as illustrated in
As illustrated in
As illustrated in
As described above, by the film formation process according to the present embodiment illustrated in
Further, by the film formation process according to the present embodiment illustrated in
Next, another example of a SiN film formation process using the plasma processing apparatus 100 will be described with reference to
The PE-ALD process according to the present embodiment illustrated in
Here, Operations S101 to S106 illustrated in
Operation S107 performing the modification is an operation of supplying the second nitrogen-containing gas (for example, N2 Gas) to generate a third plasma, and exposing the substrate W to the third plasma to modify the upper portion of the recess 601 formed on the surface of the substrate W. In other words, this operation is an operation of exciting the second nitrogen-containing gas with the third plasma. In Operation S107 performing the modification, the controller 9 controls the gas supplier 7 to supply the second nitrogen-containing gas from the gas source 71 into the processing space of the processing container 1. A N2 gas may be used as the second nitrogen-containing gas. In addition, in the following, descriptions will be made under the assumption that the N2 gas is used as the second nitrogen-containing gas. In other words, subsequent to Operation S105 performing the purging and Operation S106 forming the adsorption-inhibiting area, the controller 9 controls the gas supplier 7 to supply the second nitrogen-containing gas (N2 gas) and the inert gas (Ar gas) from the gas source 71 into the processing space of the processing chamber 1. Further, the controller 9 controls the exhaust device 8 to control the internal pressure of the processing space of the processing container 1 to the first pressure. Further, the controller 9 controls the first power supply 51 to supply the RF power to the antenna 53.
By repeating the above-described cycle, the SiN film is formed on the substrate W.
Operation S107 performing the modification improves the etching resistance of the SiN film 620. This may ensure the embedding property of the SiN film 620 to the recess 601 and enhance the etching resistance of the SiN film 620.
In addition, the SiN film formation process using the plasma processing apparatus 100 is not limited to that illustrated in
Further, when a first cycle is defined to include Operations S101 to S104, a configuration may be employed in which the first cycle is repeated a predetermined number of times, subsequently, Operations S105 and S106 are performed and Operation S101 is performed again, the first cycle is repeated a predetermined number of times, and Operations S105 and S107 are performed and Operation S101 is performed again. In other words, one of Operations S106 and Operation S107 may be executed each time the first cycle including Operations S101 to S104 is performed the predetermined number of times.
According to the present disclosure in some embodiments, it is possible to provide a substrate processing method and a substrate processing apparatus for embedding a SiN film in a recess formed in a substrate.
Although the substrate processing method of the present embodiment using the plasma processing apparatus 100 has been described above, the present disclosure is not limited to the above-described embodiment and the like, and various modifications and improvements are possible within the scope of the gist of the present disclosure described in the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-137232 | Aug 2022 | JP | national |
