TW202405936A - Substrate processing method - Google Patents

Abstract

A substrate processing method according to the present invention comprises: a step in which a substrate that comprises a silicon-containing film and a mask that is superposed on the silicon-containing film is carried into a chamber; and a step in which the silicon-containing film is etched by generating a plasma from a processing gas that contains a COF2 gas and a hydrogen-containing gas. With respect to this substrate processing method, the flow rate of the hydrogen-containing gas relative to the total flow rate of the processing gas is not less than 13% by volume but less than 50% by volume in terms of hydrogen gas.

Description

Substrate processing methods

The present invention relates to a substrate processing method.

Currently, in the manufacturing process of semiconductor devices, for example, gases such as CF ₄ (perfluoromethane) gas and cC ₄ F ₈ (perfluorocyclobutane) gas are used to perform dry etching or cleaning in the chamber. For example, Patent Document 1 below discloses plasma etching using CF ₄ gas, C ₄ F ₈ gas, or the like. Most of the gases used in these semiconductor manufacturing processes are greenhouse gases that contribute to global warming, including the Global Warming Potential (GWP), which uses CO ₂ (carbon dioxide) as the basis to indicate the ability to promote warming. Higher gas. [Prior art documents] [Patent documents]

[Patent Document 1] Japanese Patent Application Publication No. 2008-28022

[The problem that the invention aims to solve]

In the present invention, in order to suppress global warming, it is proposed to replace various gases used in various semiconductor manufacturing processes with gases with lower greenhouse effects. [Technical means to solve problems]

A substrate processing method according to one aspect of the present invention includes the following steps: carrying a substrate including a silicon-containing film and a mask laminated on the silicon-containing film into a chamber; and removing COF ₂ gas and hydrogen-containing gas from the chamber. The processing gas generates plasma to etch the silicon-containing film; the flow rate of the hydrogen-containing gas relative to the total flow rate of the processing gas, converted into hydrogen gas, is more than 13 volume % and less than 50 volume %. [Effects of the invention]

In various semiconductor manufacturing processes, by utilizing the substrate processing method using gases with lower greenhouse effect proposed in the present invention, the performance required in the semiconductor manufacturing processes can be maintained and global warming can be suppressed.

Hereinafter, embodiments of the film forming method disclosed in this application will be described in detail with reference to the drawings. Furthermore, the disclosed film forming method is not limited to this embodiment. In addition, in this specification and the drawings, components having substantially the same functional configuration are assigned the same reference numerals, and repeated descriptions are omitted.

In addition, the drawings referred to in the following description are used to facilitate the description and understanding of one embodiment of the present invention. In order to facilitate understanding, the shape, size, ratio, etc. shown in the drawings may be different from the actual ones. Furthermore, the structure shown in the drawings can be appropriately modified in design with reference to the following description and known techniques.

In recent years, in developed countries including Japan, as a countermeasure against global warming, it is required to reduce the emission of gases with high greenhouse effect such as CO ₂ gas. Currently, in the manufacturing process of semiconductor devices, as explained above, gases such as CF ₄ gas and cC ₄ F ₈ gas are used to perform dry etching or cleaning in the chamber. Most of the gases used in these semiconductor manufacturing processes are greenhouse gases that contribute to global warming, including gases with high GWPs. Therefore, it is considered important to suppress the emission of such gases with high greenhouse effect in the semiconductor manufacturing process in the future. Specifically, the GWP of the CF ₄ gas system is: 6630, and the GWP of the cC ₄ F ₈ gas system is: 9540. The higher the GWP, the higher the greenhouse effect.

Therefore, in the present invention, in order to suppress global warming, it is studied to replace various gases used in various semiconductor manufacturing processes with gases with a low greenhouse effect as a GWP of 1000 or less, preferably 100 or less. Hereinafter, details of the embodiments of the present invention will be described in sequence.

<First Embodiment> First, as a first embodiment of the present invention, it is studied to replace the dry etching step of the wiring layer used to form the logic circuit, which is one of the semiconductor device manufacturing processes, with a gas with a lower greenhouse effect.

Hereinafter, the etching steps of this embodiment will be described with reference to FIG. 1 . FIG. 1 is a cross-sectional view showing an example of the substrate W processed in this embodiment. In this embodiment, for example, the substrate W shown in FIG. 1 is etched. Specifically, as shown in FIG. 1 , the substrate W includes a base layer 210 and a film (silicon-containing film) laminated on the base layer 210 and containing silicon (Si), and has a target layer 200 to be etched. and a mask 220 laminated on the processed layer 200.

The base layer 210 may be a conductive layer such as a metal film or a silicon film. Moreover, as a metal film, for example, tungsten (W), aluminum (Al), copper (Cu), etc. can be used. Furthermore, the layer 200 to be etched may be a silicon oxide film (SiO ₂ ) or a low dielectric constant (Low-k) film. In addition, the Low-k film may be, for example, a SiOC film (carbon-containing silicon oxide film), a silicon nitride carbide film (SiCN), SiOCH (hydrocarbon-containing silicon oxide film), and combinations thereof.

Furthermore, in this embodiment, the base layer 210 is not limited to the conductive layer as described above. For example, sometimes it is desired that the base layer 210 has a high selectivity relative to the processed layer 200 and the loss of the base layer 210 is small. More specifically, for example, when forming a self-aligned contact (SAC) structure, the base layer 210 is a silicon nitride film (SiN) or the like, and the processed layer 200 is a silicon oxide film or the like. In addition, when forming a via structure, the base layer 210 is a silicon carbide film (SiC), a silicon nitride film, or the like, and the processed layer 200 is a silicon oxide film, a Low-k film, or the like.

The mask 220 has a desired opening pattern and functions as a protective film when etching a desired portion of the layer 200 to be processed. In this embodiment, the mask 220 includes at least one of carbon and metal. Specifically, in this embodiment, the mask 220 may also be a carbon-containing mask or a metal-containing mask. Furthermore, in this embodiment, the carbon-containing mask can also be spin-on carbon (SOC), tungsten carbide, amorphous carbon, boron carbide, etc., and combinations thereof. In addition, in this embodiment, the metal-containing mask may also be a titanium nitride film (TiN), a tungsten carbide film (WC), or the like.

Hereinafter, the substrate processing method of this embodiment using a gas with a low greenhouse effect as a substitute gas for etching the seed substrate W will be described.

Referring to FIG. 2 , the flow of the substrate processing method of this embodiment will be described. FIG. 2 is an explanatory diagram for explaining the flow of the substrate processing method of this embodiment. As shown in FIG. 2 , the substrate processing method according to the embodiment of the present invention includes: step (S1), which transports the substrate W described above into the plasma processing device (chamber); and step (S2), which Plasma is generated from a processing gas that will be described below, and the layer to be processed 200 is etched. Specifically, in this embodiment, for example, the mask 220 having a desired opening pattern is used to etch the layer to be processed 200 to form trenches.

The processing gas in the etching step of this embodiment includes COF ₂ (carbonyl fluoride) gas and hydrogen-containing gas.

COF ₂ gas, for example, has a lower warming effect than CF ₄ gas (GWP: 6630) used in the dry etching step for forming wiring layers of logic circuits. Therefore, in this embodiment, global warming can be suppressed by using COF ₂ gas with a lower greenhouse effect.

In addition, the hydrogen-containing gas may be one gas selected from the group consisting of hydrogen gas (H ₂ ), hydrogen fluoride (HF) gas, and hydrofluoroolefin gas, or a combination of a plurality of gases selected from these gases. In addition, the hydrofluoroolefin gas may be C ₂ H ₂ F ₂ (1,1-difluoroethylene) gas, C ₃ H ₂ F ₄ (1,3,3,3-tetrafluoropropene) gas, or C ₄ H ₂ F ₆ (trans-1,1,1,4,4,4-hexafluoro-2-butene) gas or a combination thereof. For example, the GWP of the C ₂ H ₂ F ₂ gas and C ₃ H ₂ F ₄ gas systems is 1 or less, and the GWP of the C ₄ H ₂ F ₆ gas system is 7 or less. That is, the greenhouse effect of the above-mentioned hydrogen-containing system is low, compared with CHF ₃ (trifluoromethane) (GWP: 12400) used in the dry etching step for forming the wiring layer of the logic circuit. Therefore, in this embodiment, global warming can be suppressed by using hydrogen-containing gas with a lower greenhouse effect as described above.

In addition, in this embodiment, the hydrogen-containing gas may also be C ₃ HF ₅ (pentafluoropropylene) gas, C ₄ H ₃ F ₅ (3,3,4,4,4-pentafluoro-1-butene), etc. ) gas, C ₄ HF ₅ (1,1,2,3,4-pentafluorobut-1,3-diene) gas, etc. Regarding these gases, the greenhouse effect is also low. Therefore, global warming can be suppressed by using such hydrogen-containing gases with low greenhouse effect.

Furthermore, the processing gas in the etching step of this embodiment may also include an inert gas. The inactive gas may be rare gases such as argon (Ar), helium (He), nitrogen (N ₂ ), or a combination thereof.

Furthermore, in this embodiment, for example, the mask 220 is used by the following plasma processing apparatus to treat the layer to be processed on the substrate W with plasma containing a processing gas including COF ₂ gas and a hydrogen-containing gas. 200 for etching. In this embodiment, the flow rate of the hydrogen-containing gas, converted into hydrogen gas (H ₂ ), is 13 volume % or more relative to the total flow rate of the process gas (when an inert gas is included, the process gas other than the inert gas). And less than 50 volume%. In the etching step of this embodiment, the hydrogen-containing gas system functions to extract oxygen contained in the COF ₄ gas in the form of OH. In this embodiment, by using a hydrogen-containing gas having such a function together, COF ₄ gas can function as an etching gas at the same level as gases such as CF ₄ gas that have been used heretofore. Furthermore, in this embodiment, the flow rate of the hydrogen-containing gas is defined as the volume of the hydrogen contained in the hydrogen-containing gas converted into hydrogen gas.

Here, referring to FIG. 3 , each etching rate of the photoresist, silicon oxide film, and silicon nitride film in the etching step of this embodiment is studied. FIG. 3 is a graph showing the results of the etching rate of various layers relative to the flow rate ratio of hydrogen gas. Specifically, the horizontal axis of FIG. 3 represents the ratio of the total flow rate of hydrogen to the process gas (COF ₂ ) other than the non-reactive gas, and the vertical axis represents photoresist (photoresist: PR), silicon oxide film, and silicon nitride film. Each etching rate (nm/min). Here, as the processing gas, COF ₂ gas, hydrogen gas, and nitrogen gas are used, and the photoresist, silicon oxide film, and Three of the silicon nitride films are etched.

From the results shown in Figure 3, it can be seen that even when COF ₂ gas is used as the processing gas, the silicon oxide film and the silicon nitride film are etched at the same level as when CF ₄ gas is used as the processing gas. etching. That is, according to this embodiment, even when COF ₂ gas with a lower greenhouse effect is used, the same process performance as the CF ₄ gas used so far in the process can be obtained.

Furthermore, as shown in Figure 3, it can be seen that by setting the volume ratio of the hydrogen gas flow rate to the total flow rate of the process gas to be 13% to 50% (in the range indicated by the arrow in Figure 3), the silicon oxide film is relatively The photoresist is selectively etched.

As described above, in the dry etching step for forming the wiring layer of the logic circuit, global warming can be suppressed by using the process gas with a lower greenhouse effect of the present embodiment for etching. Furthermore, according to this embodiment, even when such a gas with a low greenhouse effect is used, it is possible to obtain process performance equivalent to that of the process gas used hitherto in the process.

In addition, in the dry etching step for forming the wiring layer of the logic circuit in other embodiments, as the processing gas, for example, COF ₂ gas, CF (fluorocarbon) gas, and inert gas can also be used. In this other embodiment, the CF-based gas may be C ₃ F ₆ (hexafluoropropylene) gas, C ₄ F ₈ (octafluoro-1-butene, octafluoro-2-butene) gas, linear C ₄ F ₈ O gas or a combination thereof. Since these gases have a low greenhouse effect, global warming can be suppressed by using CF gases with a low greenhouse effect.

In addition, in the dry etching step for forming the wiring layer of the logic circuit in other embodiments, as the processing gas, for example, COF ₂ gas, CHF (hydrofluorocarbon) gas, and inert gas may also be used. In this other embodiment, the CHF-based gas may be CH ₂ F ₂ (difluoromethane) gas, CH ₃ F (fluoromethane) gas, or a combination thereof. For example, the GWP of the CH ₂ F ₂ gas system is 677, the GWP of the CH ₃ F gas system is 116, and the GWP is below 1,000. Since these gases have a low greenhouse effect, global warming can be suppressed by using CHF gases with a low greenhouse effect. Furthermore, as the processing gas in the etching step, hydrogen fluoride (HF) gas may be used instead of the CHF-based gas, or hydrogen fluoride (HF) gas may be used together with the CHF-based gas.

<Second Embodiment> Next, as a second embodiment of the present invention, it is studied to replace the dry etching step with a gas with a lower greenhouse effect in forming a DRAM (Dynamic Random Access Memory) element.

Hereinafter, the substrate processing method of this embodiment will be described with reference to FIG. 4 . FIG. 4 is a cross-sectional view showing an example of the substrate W processed in this embodiment. In this embodiment, the substrate processing method includes, for example, the step of etching the substrate W as shown in FIG. 4 . Specifically, as shown in FIG. 4 , the substrate W has a base layer 212 , a to-be-processed layer 200 that is laminated on the base layer 212 and is a target of etching, and a mask 220 that is laminated on the to-be-processed layer 200 . Hereinafter, each layer of the substrate W will be described. However, description of the points common to the above-described embodiment will be omitted.

In this embodiment, the base layer 212 can be, for example, a metal film, a silicon film, etc., and is not particularly limited.

Furthermore, in this embodiment, the layer to be processed 200 may also include one oxide film (for example, silicon oxide film) and one or more nitride films (for example, silicon nitride film). In this embodiment, for example, as shown in FIG. 4 , the layer to be processed 200 has two silicon nitride films 204 and a silicon oxide film 202 sandwiched between the two silicon nitride films 204 . For example, the silicon oxide film 202 has a film thickness of about 800 nm to 1200 nm, and the silicon nitride film 204 has a film thickness of about 300 nm to 400 nm.

In this embodiment, a mask 220 with a desired opening pattern is used to etch the processed layer 200 to form trenches. The groove may be, for example, substantially cylindrical with a depth of about 1 μm to 3 μm. In addition, the substantially cylindrical shape may have a diameter of about 20 nm to 50 nm, for example. Moreover, a capacitor memory cell, for example, can be formed inside such a substantially cylindrical trench.

Hereinafter, the etching steps included in the substrate processing method of this embodiment using a gas with a low greenhouse effect as a substitute gas for etching such a substrate W will be described. In this embodiment, for example, a mask 220 having a desired opening pattern is used to etch the layer 200 to be processed to form a trench.

The processing gas in the etching step of this embodiment includes CF (fluorocarbon) gas and inert gas. The CF-based gas may be C ₃ F ₆ (hexafluoropropylene) gas, C ₄ F ₈ (octafluoro-1-butene, octafluoro-2-butene) gas, or a combination thereof. For example, the GWP of the C ₃ F ₆ gas system is less than 1, which is equivalent to the C ₄ F ₆ (hexafluoro-1,3-butadiene) gas (GWP: 290) used in the dry etching step to form DRAM components. than, has a lower GWP. Therefore, in this embodiment, global warming can be suppressed by using hydrogen-containing gas with a lower greenhouse effect as described above.

In addition, the inert gas may be a rare gas such as argon or helium, nitrogen, or a combination thereof.

Furthermore, in this embodiment, the processing gas may also contain oxygen (O ₂ ).

As mentioned above, in the dry etching step for forming DRAM elements, global warming can be suppressed by using the process gas with a lower greenhouse effect of this embodiment for etching. Furthermore, according to this embodiment, even when such a gas with a low greenhouse effect is used, it is possible to obtain process performance equivalent to that of the process gas used hitherto in the process.

<3rd Embodiment> Next, as a third embodiment of the present invention, it is studied to replace the dry etching step for forming a vertical NAND (Not AND) type flash memory device with a gas with a lower greenhouse effect. Furthermore, the vertical NAND structure is also called VNAND and 3D-NAND structure.

Hereinafter, the substrate processing method of this embodiment will be described with reference to FIG. 5 . FIG. 5 is a cross-sectional view showing an example of the substrate W processed in this embodiment. In this embodiment, the substrate processing method includes, for example, the step of etching the substrate W as shown in FIG. 5 . Specifically, as shown in FIG. 5 , the substrate W has a base layer 212 , a to-be-processed layer 200 that is laminated on the base layer 212 and is a target of etching, and a mask 220 that is laminated on the to-be-processed layer 200 . Hereinafter, each layer of the substrate W will be described. However, description of the points common to the above-described embodiment will be omitted.

In this embodiment, the base layer 212 can be, for example, a metal film, a silicon film, etc., and is not particularly limited.

In this embodiment, as shown in FIG. 5 , the processed layer 200 may also include a plurality of films including an oxide film 202 (for example, silicon oxide film) and a nitride film 204 (for example, silicon nitride film). Layered structure. Alternatively, the layer to be processed 200 may also include a plurality of laminated structures including one oxide film (eg, silicon oxide film) and one silicon film (eg, polycrystalline silicon film). Furthermore, the layer to be processed 200 may include at least about 20 of the above-described laminated structures, preferably about 40, more preferably about 60, and still more preferably about 70. Furthermore, in FIG. 5 , for the sake of convenience, the layer to be processed 200 is illustrated as including five of the above-mentioned layered structures. In this embodiment, the layer to be processed 200 only needs to include at least about 20 of the above-mentioned layered structures. , its quantity is not limited.

In this embodiment, a mask 220 with a desired opening pattern is used to etch the processed layer 200 to form trenches. The trench has a depth of about 2 μm to 6 μm, for example. In addition, the trench may have a width of about 50 nm to 150 nm, for example.

Hereinafter, the etching steps included in the substrate processing method of this embodiment using a gas with a low greenhouse effect as a substitute gas for etching the substrate W will be described. In this embodiment, for example, a mask 220 having a desired opening pattern is used to etch the layer 200 to be processed to form a trench.

The processing gas in the etching step of this embodiment includes CF-based gas, hydrogen-containing gas, and oxygen. The CF-based gas may be C ₃ F ₆ (hexafluoropropylene) gas, C ₄ F ₈ (octafluoro-1-butene, octafluoro-2-butene) gas, or a combination thereof. As explained above, for example, the GWP of the C ₃ F ₆ gas system is 1 or less. Moreover, C ₃ F ₆ gas and the like have better performance than the cC ₄ F ₈ (perfluorocyclobutane) gas (GWP: 9540) previously used in the dry etching step for forming vertical NAND flash memory devices. Lower GWP. Furthermore, C ₃ F ₆ gas and the like have a lower GWP than the previously used NF ₃ (nitrogen trifluoride) gas (GWP: 16100) and SF ₆ (sulfur hexafluoride) gas (GWP: 23500). Therefore, in this embodiment, global warming can be suppressed by using the CF-based gas with a low greenhouse effect as described above.

Furthermore, the hydrogen-containing gas may be one gas selected from the group consisting of hydrogen gas, hydrogen fluoride gas, and hydrofluoroolefin gas, or a combination of a plurality of gases selected from these. In addition, the hydrofluoroolefin gas may be C ₂ H ₂ F ₂ (1,1-difluoroethylene) gas, C ₃ H ₂ F ₄ (1,3,3,3-tetrafluoropropene) gas, or C ₄ H ₂ F ₆ (trans-1,1,1,4,4,4-hexafluoro-2-butene) gas or a combination thereof. Regarding these gases, as explained above, the greenhouse effect is low. For example, the GWP of the C ₃ H ₂ F ₄ gas system is 1 or less, and the GWP of the C ₄ H ₂ F ₆ gas system is 7 or less. Therefore, in this embodiment, global warming can be suppressed by using hydrogen-containing gas with a lower greenhouse effect as described above.

As mentioned above, in the dry etching step for forming the vertical NAND type device, global warming can be suppressed by using the process gas with a lower greenhouse effect of the present embodiment for etching. Furthermore, according to this embodiment, even when such a gas with a low greenhouse effect is used, it is possible to obtain process performance equivalent to that of the process gas used hitherto in the process.

<4th Embodiment> In the manufacturing process of semiconductor components, various semiconductor components such as microprocessors, logic circuits, and memory components are formed. Such semiconductor devices can be fabricated by processes involving patterning techniques that create various types of masks. Specifically, in such several processes, layers including silicon oxide film, silicon nitride film, silicon film, etc. are etched. Next, an etching step using a gas with a lower greenhouse effect as a substitute gas will be described.

(Silicon Oxide Film) The process gas used in the etching step of the silicon oxide film in this embodiment includes CF-based gas, oxygen, and inert gas. The CF-based gas may be C ₃ F ₆ (hexafluoropropylene) gas, C ₄ F ₈ (octafluoro-1-butene, octafluoro-2-butene) gas, or a combination thereof. As explained above, for example, the GWP of the C ₃ F ₆ gas system is 1 or less, and the CF ₄ gas (GWP: 6630) and CHF ₃ (trifluoromethane) gas (GWP: 1) used in the etching step of the silicon oxide film are: 12400), has a lower GWP. Therefore, in this embodiment, global warming can be suppressed by using the CF-based gas with a low greenhouse effect as described above.

In addition, the inert gas may be a rare gas such as argon or helium, nitrogen, or a combination thereof.

In addition, the processing gas in the etching step of the silicon oxide film in this embodiment may also include CF-based gas and CHF (hydrofluorocarbon)-based gas. The CF series gas may be COF ₂ gas, C ₄ F ₈ O (pentafluoroethyl trifluoroethylene ether) gas, CF ₃ COF (1,2,2,2-tetrafluoroethane-1-one) gas or the A combination of others. Examples of the CHF-based gas include CHF ₂ COF (fluorine difluoroacetate) gas and the like. Therefore, in this embodiment, global warming can be suppressed by using CF-based gas and CHF-based gas with low greenhouse effect as described above. Furthermore, in the processing gas in the above-mentioned etching step, hydrogen fluoride (HF) gas may be used instead of CHF-based gas, or hydrogen fluoride (HF) gas may be used together with CHF-based gas.

(Silicon nitride film) In this embodiment, the processing gas in the etching step of the silicon nitride film includes hydrogen-containing gas, oxygen, and inert gas. The hydrogen-containing gas may be one gas selected from the group consisting of hydrogen gas, hydrogen fluoride gas, and hydrofluoroolefin gas, or a combination of a plurality of gases selected from these. In addition, the hydrofluoroolefin gas may be C ₂ H ₂ F ₂ (1,1-difluoroethylene) gas, C ₃ H ₂ F ₄ (1,3,3,3-tetrafluoropropene) gas, or C ₄ H ₂ F ₆ (trans-1,1,1,4,4,4-hexafluoro-2-butene) gas or a combination thereof. For example, the GWP of the C ₃ H ₂ F ₄ gas system is 1, the GWP of the C ₄ H ₂ F ₆ gas system is 7 or less, and the CH ₃ F (fluoromethane) gas (GWP) used in the etching step of the silicon nitride film is :116), has a lower GWP. Therefore, in this embodiment, global warming can be suppressed by using hydrogen-containing gas with a lower greenhouse effect as described above.

In addition, the inert gas may be a rare gas such as argon or helium, nitrogen, or a combination thereof.

(Silicon Film) In this embodiment, the processing gas used in the etching step of the silicon film includes hydrogen-containing gas, oxygen, and inert gas. The hydrogen-containing gas may include hydrogen fluoride gas, hydrogen bromide (HBr) gas, etc. For example, HBr gas has a lower GWP than NF ₃ (nitrogen trifluoride) gas (GWP: 16100) used in the etching step of the silicon film. Therefore, in this embodiment, global warming can be suppressed by using hydrogen-containing gas with a lower greenhouse effect as described above.

In addition, the inert gas may be a rare gas such as argon or helium, nitrogen, or a combination thereof.

As described above, in the etching step for patterning a layer containing a silicon oxide film, a silicon nitride film, a silicon film, etc., by etching using a processing gas with a low greenhouse effect according to this embodiment, it is possible to Suppress global warming. Furthermore, according to this embodiment, even when such a gas with a low greenhouse effect is used, it is possible to obtain process performance equivalent to that of the process gas used hitherto in the process.

<5th Embodiment> In the manufacturing process of semiconductor devices, various chambers are used in order to generate plasma and use the generated plasma to process substrates. During the process of such treatment, the by-products generated during the treatment adhere to the inner wall of the chamber, etc., and then the by-products gradually deposit and grow into particles. Since such particles may have adverse effects on stable plasma generation or substrate processing, in order to reduce particles on the inner walls, etc., the chamber is dry-cleaned at specific intervals.

Specifically, in dry cleaning of such a chamber, cleaning gas and inert gas are supplied into the chamber, plasma is generated using the supplied gas, and the inner wall of the chamber and the like are cleaned by the plasma. Examples of cleaning gases that have been used conventionally include NF ₃ (nitrogen trifluoride) gas (GWP: 16100), SF ₆ (sulfur hexafluoride) gas (GWP: 23500), etc., but these gas systems The GWP is higher, that is, the greenhouse effect is higher.

Hereinafter, cleaning according to this embodiment using a gas with a lower greenhouse effect as a substitute gas in such cleaning will be described.

In this embodiment, the cleaning gas may be COF ₂ gas, HF (hydrogen fluoride) gas, fluorine gas (F ₂ ), FNO (nitroso fluorine) gas, F ₃ NO (ammonium trifluoride oxide) gas, or any of these gases. combination. These gases have a lower greenhouse effect than NF ₃ gas (GWP16100), SF ₆ gas (GWP23500), etc., which have been used as cleaning gases so far. Therefore, in this embodiment, global warming can be suppressed by using a cleaning gas with a lower greenhouse effect as described above.

As mentioned above, in the dry cleaning of the chamber, global warming can be suppressed by using the cleaning gas with lower greenhouse effect of this embodiment for cleaning. Furthermore, according to this embodiment, even when such a gas with a low greenhouse effect is used, it is possible to obtain cleaning performance equivalent to that of the cleaning gas used hitherto for this cleaning.

＜Plasma treatment equipment＞ Next, an example of a plasma processing apparatus applicable to the substrate processing method of each embodiment of the present invention will be described. FIG. 6 is a diagram illustrating a configuration example of a capacitive coupling type plasma processing apparatus.

As shown in FIG. 6 , the plasma treatment system includes a capacitively coupled plasma treatment device 1 and a control unit 2 . The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10 , a gas supply unit 20 , a power supply 30 and an exhaust system 40 . Moreover, the plasma processing apparatus 1 includes a substrate support part 11 and a gas introduction part. The gas introduction part is configured to introduce at least one processing gas into the plasma processing chamber 10 . The gas introduction part includes the shower head 13 . The substrate support part 11 is arranged in the plasma processing chamber 10 . The shower head 13 is arranged above the substrate support part 11 . In one embodiment, the shower head 13 forms at least a portion of the ceiling of the plasma processing chamber 10 . The plasma processing chamber 10 has a plasma processing space 10 s defined by the shower head 13 , the side wall 10 a of the plasma processing chamber 10 and the substrate support 11 . The plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s, and at least one gas exhaust port for discharging the gas from the plasma processing space. Plasma processing chamber 10 is grounded. The shower head 13 and the substrate support part 11 are electrically insulated from the casing of the plasma processing chamber 10 .

The substrate support part 11 includes a main body part 111 and a ring assembly 112 . The main body part 111 has a central area 111a for supporting the substrate W, and an annular area 111b for supporting the ring assembly 112. The wafer is an example of the substrate W. The annular area 111b of the main body part 111 surrounds the central area 111a of the main body part 111 when viewed from above. The substrate W is disposed on the central region 111 a of the main body 111 , and the ring component 112 is disposed on the annular region 111 b of the main body 111 to surround the substrate W on the central region 111 a of the main body 111 . Therefore, the central region 111 a is also called a substrate supporting surface for supporting the substrate W, and the annular region 111 b is also called a ring supporting surface for supporting the ring assembly 112 .

In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is arranged on the base 1110 . The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b arranged in the ceramic member 1111a. Ceramic member 1111a has a central region 111a. In one embodiment, the ceramic component 1111a also has an annular region 111b. Furthermore, other components surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may also have an annular region 111b. In this case, the ring component 112 may also be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. In addition, at least one RF/DC electrode coupled to the RF power supply 31 and/or the DC (Direct Current, DC) power supply 32 described below may be arranged in the ceramic member 1111a. In this case, at least one RF/DC electrode functions as the lower electrode. When the following bias RF signal and/or DC signal is supplied to at least one RF/DC electrode, the RF/DC electrode is also called a bias electrode. Furthermore, the conductive member and at least one RF/DC electrode of the base 1110 may also function as a plurality of lower electrodes. In addition, the electrostatic electrode 1111b may also function as a lower electrode. Therefore, the substrate support portion 11 includes at least one lower electrode.

The ring assembly 112 includes one or a plurality of ring-shaped members. In one embodiment, one or more ring-shaped members include one or more edge rings and at least one cover ring. The edge ring is formed of conductive material or insulating material, and the cover ring is formed of insulating material.

In addition, the substrate support part 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may also include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid such as salt water or gas flows through the counter flow path 1110a. In one embodiment, the flow path 1110a is formed in the base 1110, and one or a plurality of heaters are arranged in the ceramic component 1111a of the electrostatic chuck 1111. In addition, the substrate support part 11 may include a heat transfer gas supply part configured to supply heat transfer gas to the gap between the back surface of the substrate W and the central region 111a.

The shower head 13 is configured to introduce at least one kind of processing gas from the gas supply unit 20 into the plasma processing space 10 s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas introduction ports 13c. The processing gas supplied to the gas supply port 13a is introduced into the plasma processing space 10s from the plurality of gas introduction ports 13c through the gas diffusion chamber 13b. In addition, the shower head 13 includes at least one upper electrode. Furthermore, in addition to the shower head 13, the gas introduction part may also include one or a plurality of side gas injectors (SGI) installed in one or a plurality of openings formed in the side wall 10a.

The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22 . In one embodiment, the gas supply unit 20 is configured to supply at least one processing gas from corresponding gas sources 21 to the shower heads 13 through corresponding flow controllers 22 . Each flow controller 22 may also include a mass flow controller or a pressure control type flow controller, for example. Furthermore, the gas supply unit 20 may include one or more flow rate modulating elements that modulate or pulse the flow rate of at least one processing gas.

Power supply 30 includes an RF power supply 31 coupled to plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and/or at least one upper electrode. Thereby, plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least part of a plasma generating unit configured to generate plasma from one or more processing gases in the plasma processing chamber 10 . Furthermore, by supplying a bias RF signal to at least one lower electrode to generate a bias potential on the substrate W, the ion component in the formed plasma can be fed to the substrate W.

In one embodiment, the RF power supply 31 includes a first RF generating part 31a and a second RF generating part 31b. The first RF generating unit 31a is coupled to at least one lower electrode and/or at least one upper electrode via at least one impedance matching circuit, and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may also be configured to generate a plurality of source RF signals with different frequencies. The generated source RF signal or signals are supplied to at least one lower electrode and/or at least one upper electrode.

The second RF generating unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal can be the same as the frequency of the source RF signal, or it can be different. In one embodiment, the bias RF signal has a lower frequency than the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generating unit 31b may also be configured to generate a plurality of bias RF signals with different frequencies. One or more of the generated bias RF signals are supplied to at least one lower electrode. Furthermore, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

Alternatively, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10 . The DC power supply 32 includes a first DC generating unit 32a and a second DC generating unit 32b. In one embodiment, the first DC generating unit 32a is connected to at least one lower electrode and is configured to generate a first DC signal. The generated first bias DC signal is applied to at least one lower electrode. In one embodiment, the second DC generating unit 32b is connected to at least one upper electrode and is configured to generate a second DC signal. The generated second DC signal is applied to at least one upper electrode.

In various embodiments, at least one of the first and second DC signals may also be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and/or at least one upper electrode. The voltage pulse may also have a rectangular, trapezoidal, triangular or a combination of these pulse waveforms. In one embodiment, a waveform generating part for generating a sequence of voltage pulses from a DC signal is connected between the first DC generating part 32a and at least one lower electrode. Therefore, the first DC generating unit 32a and the waveform generating unit constitute a voltage pulse generating unit. When the second DC generating part 32b and the waveform generating part constitute a voltage pulse generating part, the voltage pulse generating part is connected to at least one upper electrode. The voltage pulse can have positive or negative polarity. In addition, the sequence of voltage pulses may also include one or a plurality of positive polarity voltage pulses and one or a plurality of negative polarity voltage pulses within one cycle. Furthermore, the first and second DC generating parts 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generating part 32a may be provided in place of the second RF generating part 31b.

For example, the exhaust system 40 may be connected to the gas exhaust port 10e provided at the bottom of the plasma processing chamber 10 . The exhaust system 40 may also include a pressure regulating valve and a vacuum pump. Use the pressure adjustment valve to adjust the pressure in the plasma processing space within 10 seconds. Vacuum pumps may also include turbomolecular pumps, dry vacuum pumps, or combinations thereof.

The control unit 2 processes computer-executable commands that cause the plasma processing device 1 to execute various steps described in the present invention. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to execute various steps described here. In one embodiment, part or all of the control unit 2 may also be included in the plasma processing device 1 . The control unit 2 may also include a processing unit 2a1, a memory unit 2a2, and a communication interface 2a3. The control unit 2 can be realized by a computer 2a, for example. The processing unit 2a1 may be configured to read a program from the memory unit 2a2 and execute the read program to perform various control operations. The program can be stored in the memory unit 2a2 in advance, or can be obtained through the media when needed. The obtained program is stored in the memory unit 2a2, and is read out from the memory unit 2a2 by the processing unit 2a1 and executed. The media may be various memory media that can be read by the computer 2a, or may be a communication line connected to the communication interface 2a3. The processing unit 2a1 may also be a CPU (Central Processing Unit). The memory unit 2a2 may also include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive) drive), or a combination of these. The communication interface 2a3 can also communicate with the plasma processing device 1 via a communication line such as a LAN (Local Area Network).

Furthermore, the substrate processing method according to each embodiment of the present invention is not limited to using the plasma processing apparatus shown in FIG. 6 , and various plasma processing apparatuses can be used according to each manufacturing process. For example, in the plasma processing apparatus shown in FIG. 6 , capacitively coupled plasma (CCP) is used as the plasma source, but the embodiment of the present invention is not limited to this. For example, in addition to capacitively coupled plasma (CCP), inductively coupled plasma (ICP), microwave excited surface plasma (SWP), etc. may also be used.

<Summary> As described above, the substrate processing method according to the embodiment of the present invention includes the following steps: carrying in the substrate W including the silicon-containing film (the layer to be processed 200 ) and the mask 220 laminated on the silicon-containing film 200 into the chamber; and generate plasma from the processing gas including COF ₂ gas and hydrogen-containing gas to etch the silicon-containing film 200; the flow rate of the hydrogen-containing gas relative to the total flow rate of the above-mentioned processing gas is converted into hydrogen gas, It is 13 volume% or more and less than 50 volume%. Thereby, the substrate processing method according to the embodiment of the present invention can suppress global warming and obtain the same process performance as the processing gas used in the substrate processing method hitherto.

Furthermore, according to an embodiment of the present invention, the hydrogen-containing gas may include at least one selected from the group consisting of hydrogen gas, hydrogen fluoride gas, and hydrofluoroolefin gas.

Furthermore, according to an embodiment of the present invention, the hydrofluoroolefin gas may include a gas selected from the group consisting of C ₂ H ₂ F ₂ (1,1-vinylidene fluoride) gas, C ₃ H ₂ F ₄ (1,3,3,3- At least one of the group consisting of tetrafluoropropylene) gas and C ₄ H ₂ F ₆ (trans-1,1,1,4,4,4-hexafluoro-2-butene) gas.

Furthermore, according to the embodiment of the present invention, the processing gas may further include an inert gas, and the inert gas may include at least one of a rare gas and nitrogen.

Furthermore, according to the embodiment of the present invention, the silicon-containing film (processed layer 200 ) may include a silicon oxide film or a Low-k film.

Furthermore, according to an embodiment of the present invention, the Low-k film may include at least one selected from the group consisting of a SiOC film, a SiCN film, and a SiOCH film.

Furthermore, according to embodiments of the present invention, the mask 220 may include at least one of carbon and metal.

Furthermore, according to an embodiment of the present invention, the carbon-containing mask may include at least one selected from the group consisting of spin-coated carbon, tungsten carbide, amorphous carbon, and boron carbide.

Furthermore, according to an embodiment of the present invention, the etching step may be an etching step for forming a wiring layer of a logic circuit.

Furthermore, according to an embodiment of the present invention, the plasma may be capacitively coupled plasma.

＜Supplement＞ The embodiments of the present invention have been described above, but it should be understood that the embodiments disclosed this time are illustrative in all respects and not restrictive. That is, the above-described embodiment can be implemented in various forms. In addition, the above-described embodiments may be omitted, replaced, changed, or combined in various forms without departing from the scope of the patent application and the gist thereof.

In addition, the effects described in this specification are merely illustrative or illustrative and not restrictive. That is, the technology of the present invention can exhibit other effects that are apparent to those skilled in the art from the description of this specification, together with or instead of the above-mentioned effects.

Furthermore, the present invention may adopt the following configuration. (1) A substrate processing method, which includes the following steps: carrying a substrate including a silicon-containing film and a mask laminated on the silicon-containing film into a chamber; and processing self-contained COF ₂ gas and hydrogen-containing gas. The gas generates plasma to etch the silicon-containing film; the flow rate of the hydrogen-containing gas relative to the total flow rate of the process gas, converted into hydrogen gas, is more than 13 volume % and less than 50 volume %. (2) The substrate processing method according to the above (1), wherein the hydrogen-containing gas contains at least one member selected from the group consisting of hydrogen gas, hydrogen fluoride gas, and hydrofluoroolefin gas. (3) The substrate processing method according to the above (2), wherein the hydrofluoroolefin gas contains a gas selected from the group consisting of C ₂ H ₂ F ₂ (1,1-vinylidene fluoride) gas, C ₃ H ₂ F ₄ (1,3 ,3,3-tetrafluoropropene) gas, and C ₄ H ₂ F ₆ (trans-1,1,1,4,4,4-hexafluoro-2-butene) gas, at least one of the group consisting of One. (4) The substrate processing method according to any one of the above (1) to (3), wherein the processing gas further includes an inert gas, and the inert gas includes at least one of a rare gas and nitrogen. (5) The substrate processing method according to any one of the above (1) to (4), wherein the silicon-containing film includes a silicon oxide film or a Low-k film. (6) The substrate processing method according to the above (5), wherein the Low-k film contains at least one selected from the group consisting of SiOC film, SiCN film, and SiOCH film. (7) The substrate processing method according to any one of the above (1) to (6), wherein the mask contains at least one of carbon and metal. (8) The substrate processing method according to the above (7), wherein the carbon-containing mask contains at least one member selected from the group consisting of spin-coated carbon, tungsten carbide, amorphous carbon, and boron carbide. (9) The substrate processing method according to any one of the above (1) to (8), wherein the etching step is an etching step for forming a wiring layer of a logic circuit. (10) The substrate processing method according to any one of the above (1) to (9), wherein the plasma is a capacitively coupled plasma.

1: Plasma treatment device 2:Control Department 2a:Computer 2a1:Processing Department 2a2:Memory Department 2a3: Communication interface 10:Plasma processing chamber 10a:Side wall 10e:Gas discharge port 10s: Plasma processing space 11:Substrate support department 13: shower head 13a:Gas supply port 13b: Gas diffusion chamber 13c:Gas inlet 20:Gas supply department 21:Gas source 22:Flow controller 30:Power supply 31:RF power supply 31a, 31b: RF generation part 32:DC power supply 32a, 32b: DC generation part 40:Exhaust system 111: Ontology Department 111a:Central area 111b: Ring area 112:Ring assembly 200: Processed layer 202:Silicon oxide film 204: Silicon nitride film 210,212: Basal layer 220:Mask 1110:Abutment 1110a: Flow path 1111:Electrostatic sucker 1111a: Ceramic components 1111b: Electrostatic electrode W: substrate

FIG. 1 is a cross-sectional view showing an example of a substrate. FIG. 2 is an explanatory diagram for explaining the flow of the substrate processing method according to the first embodiment of the present invention. FIG. 3 is a graph showing the results of the etching rate of various layers relative to the flow rate ratio of hydrogen gas. FIG. 4 is a cross-sectional view showing an example of the substrate. FIG. 5 is a cross-sectional view showing an example of the substrate. FIG. 6 is a diagram illustrating a configuration example of a capacitive coupling type plasma processing apparatus.

Claims (10)

A substrate processing method, which includes the following steps: moving a substrate including a silicon-containing film and a mask laminated on the silicon-containing film into a chamber; and generating electricity from a processing gas containing COF ₂ gas and a hydrogen-containing gas. The slurry is used to etch the silicon-containing film; the flow rate of the hydrogen-containing gas relative to the total flow rate of the process gas, converted into hydrogen gas, is more than 13 volume % and less than 50 volume %. The substrate processing method of claim 1, wherein the hydrogen-containing gas includes at least one member selected from the group consisting of hydrogen gas, hydrogen fluoride gas, and hydrofluoroolefin gas. The substrate processing method of claim 2, wherein the hydrofluoroolefin gas includes a gas selected from the group consisting of C ₂ H ₂ F ₂ (1,1-vinylidene fluoride) gas, C ₃ H ₂ F ₄ (1,3,3,3- At least one of the group consisting of tetrafluoropropylene) gas and C ₄ H ₂ F ₆ (trans-1,1,1,4,4,4-hexafluoro-2-butene) gas. The substrate processing method of claim 1, wherein the processing gas further includes an inert gas, and the inert gas includes at least one of a rare gas and nitrogen. The substrate processing method of claim 1, wherein the silicon-containing film includes a silicon oxide film or a Low-k film. The substrate processing method of claim 5, wherein the Low-k film includes at least one selected from the group consisting of SiOC film, SiCN film, and SiOCH film. The substrate processing method of claim 1, wherein the mask contains at least one of carbon and metal. The substrate processing method of claim 7, wherein the carbon-containing mask includes at least one member selected from the group consisting of spin-coated carbon, tungsten carbide, amorphous carbon, and boron carbide. The substrate processing method of claim 1, wherein the etching step is an etching step used to form a wiring layer of a logic circuit. The substrate processing method of claim 1, wherein the plasma is a capacitively coupled plasma.