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JP-7854801-B2 - Thin film deposition method and thin film deposition apparatus

JP7854801B2JP 7854801 B2JP7854801 B2JP 7854801B2JP-7854801-B2

Inventors

  • 根石 浩司

Assignees

  • 東京エレクトロン株式会社

Dates

Publication Date
20260507
Application Date
20211228

Claims (16)

  1. A method for forming a metal oxide film on a substrate inside a processing container, The process involves supplying a raw material gas containing an organometallic precursor in which an organic ligand is bound to the metal element of the metal oxide film to be formed into the processing container, The step of supplying the raw material gas is followed by the step of removing the residual gas remaining in the processing container, The next step is to supply an oxidizing agent for oxidizing the raw material gas into the processing container, The step of supplying the oxidizing agent is followed by the step of removing residual gas remaining in the processing container, A step of supplying a reducing gas containing hydrogen into the processing container at the same time as supplying the raw material gas, wherein the supply of the reducing gas causes the organic ligand to be detached from the organometallic precursor and promotes the thermal decomposition of the organometallic precursor to lower the film deposition temperature, A film formation method having the following characteristics.
  2. The film-forming method according to claim 1, comprising repeating the steps of supplying the raw material gas, removing the residual gas after supplying the raw material gas, supplying the oxidizing agent, and removing the residual gas after supplying the oxidizing agent multiple times, with each cycle including the step of supplying the hydrogen-containing reducing gas.
  3. A film deposition method for depositing a multi-component metal oxide film on a substrate in a processing container, the multi-component metal oxide film being composed of multiple metal oxide films each containing a different metal, The process comprises several steps for forming each of the aforementioned multiple metal oxide films. Each of the above steps is: The process involves supplying a raw material gas containing an organometallic precursor in which an organic ligand is bound to the metal element of the metal oxide film to be formed into the processing container, The step of supplying the raw material gas is followed by the step of removing the residual gas remaining in the processing container, The next step is to supply an oxidizing agent for oxidizing the raw material gas into the processing container, The step of supplying the oxidizing agent is followed by the step of removing residual gas remaining in the processing container, It has, A method for forming a film, wherein at least one of the aforementioned steps is a step of supplying a reducing gas containing hydrogen into the processing vessel at the same time as the step of supplying the raw material gas , the supply of which causes the organic ligand to be detached from the organometallic precursor and promotes the thermal decomposition of the organometallic precursor to lower the film formation temperature.
  4. Of the aforementioned multiple steps, the one that includes the step of supplying the reducing gas containing hydrogen is: The film formation method according to claim 3, wherein the steps of supplying the raw material gas, removing the residual gas after the supply of the raw material gas, supplying the oxidizing agent, and removing the residual gas after the supply of the oxidizing agent are repeated multiple times, and in each cycle the step of supplying the reducing gas containing the hydrogen is performed.
  5. The film formation method according to claim 3 or claim 4, wherein the above-mentioned multiple steps are repeated multiple times.
  6. The film deposition method according to any one of claims 3 to 5, wherein the step of supplying a reducing gas containing hydrogen is performed simultaneously with the step of supplying the raw material gas, thereby lowering the film deposition temperature of the metal oxide film deposited in the step and aligning the optimal film deposition temperatures of the multi-component metal oxide film.
  7. The film formation method according to any one of claims 3 to 6, wherein the plurality of metal oxide films are an InOx film, a GaOx film, and a ZnO film, and the multi-component metal oxide film is an InGaZnO film.
  8. The film formation method according to claim 7, wherein the step of forming the GaOx film comprises the step of supplying the hydrogen-containing reducing gas.
  9. The film formation method according to claim 7, wherein the steps of forming the GaOx film and forming the InOx film each include the step of supplying a reducing gas containing hydrogen.
  10. The film deposition method according to claim 9, wherein the amount of hydrogen-containing reducing gas supplied in the step of supplying the hydrogen-containing reducing gas is less when depositing the InOx film than when depositing the GaOx film.
  11. The film-forming method according to any one of claims 1 to 10, wherein the step of removing residual gas after the step of supplying the raw material gas also removes residual gas remaining after the step of supplying the hydrogen-containing reducing gas.
  12. While the steps of supplying the raw material gas, removing residual gas after the supply of the raw material gas, supplying the oxidizing agent, and removing residual gas after the supply of the oxidizing agent are being carried out, a continuous purge gas is supplied to flow continuously into the processing container. The steps of removing residual gas after the step of supplying the raw material gas and removing residual gas after the step of supplying the oxidizer are performed using the continuous purge gas. The film formation method according to claim 11, wherein, in the step of removing residual gas after the step of supplying the raw material gas, an additional purge gas is supplied in addition to the continuous purge gas.
  13. The film-forming method according to claim 12, wherein the pressure inside the processing container is reduced during the step of removing residual gas after the step of supplying the raw material gas.
  14. The method for forming a film according to any one of claims 1 to 13, wherein the organic ligand of the organometallic precursor is an alkyl group, the step of supplying the hydrogen-containing reducing gas is to detach the alkyl group from the organometallic precursor adsorbed on the substrate and terminate it with hydrogen, and the step of supplying the oxidizing agent suppresses the generation of H₂O .
  15. The method for forming a film according to any one of claims 1 to 14 , wherein the reducing gas containing hydrogen is hydrogen gas.
  16. A film deposition apparatus for depositing a metal oxide film on a substrate, A processing container in which the substrate is housed, A mounting platform for placing the substrate within the processing container, A gas supply unit that supplies gas to the processing container, An exhaust unit for exhausting the contents of the processing container, It has a control unit, The control unit, The process involves supplying a raw material gas containing an organometallic precursor in which an organic ligand is bound to the metal element of the metal oxide film to be formed into the processing container, The step of supplying the raw material gas is followed by the step of removing the residual gas remaining in the processing container, The next step is to supply an oxidizing agent for oxidizing the raw material gas into the processing container, The step of supplying the oxidizing agent is followed by the step of removing residual gas remaining in the processing container, A step of supplying a reducing gas containing hydrogen into the processing container at the same time as supplying the raw material gas, wherein the supply of the reducing gas causes the organic ligand to be detached from the organometallic precursor and promotes the thermal decomposition of the organometallic precursor to lower the film deposition temperature, A film deposition apparatus that controls the gas supply unit and the exhaust unit so that the following occurs.

Description

This disclosure relates to a film deposition method and a film deposition apparatus. Atomic layer deposition (ALD) is a known method for depositing metal oxide films, in which organometallic precursors and oxidizing agents are supplied alternately. Patent Document 1 describes the process of depositing multi-component metal oxide films, such as IGZO, using the ALD method, specifically by sequentially depositing individual metal oxide films. Furthermore, it describes how the proportion of each metal oxide film in the film thickness direction can be altered by changing the frequency of the formation step for a specific metal oxide film. Special table 2016-511936 publication This is a timing chart showing the gas supply timing in an example of a film deposition method according to the first embodiment.This is a timing chart showing the gas supply timing in another example of the film deposition method according to the first embodiment.This diagram illustrates the effect of reducing impurities when H2 gas is supplied.This diagram illustrates the effect of reducing H₂O generation when H₂ gas is supplied.This is a timing chart showing the gas supply timing in yet another example of the film deposition method according to the first embodiment.This is a timing chart showing the gas supply timing in an example of a film deposition method according to the second embodiment.This is a timing chart showing the gas supply timing in another example of the film deposition method according to the second embodiment.This is a timing chart showing the gas supply timing in yet another example of the film deposition method according to the second embodiment.This is a schematic cross-sectional view showing an IGZO film, which is a specific example of a multi-metal oxide film to be formed in the second embodiment.This figure shows the relationship between substrate temperature and film thickness, and the relationship between substrate temperature and impurity concentration, when depositing an Inox film using the conventional ALD method.This figure shows the relationship between substrate temperature and film thickness, and the relationship between substrate temperature and impurity concentration, when depositing a GaOx film using the conventional ALD method.This figure shows the relationship between substrate temperature and film thickness, and the relationship between substrate temperature and impurity concentration, when depositing a ZnOx film using the conventional ALD method.This figure shows the reduction in the ALD window temperature range when triethylgallium and H2 gas are supplied simultaneously during GaOx film deposition.This is a cross-sectional view showing an example of a film deposition apparatus used in a film deposition method. The embodiments will be described below with reference to the attached drawings. <Film formation method> First, an embodiment of the film deposition method will be described. [First Embodiment] In this embodiment, a metal oxide film is formed by the ALD method while the substrate is housed in a processing container. Figure 1 is a timing chart showing the gas supply timing in an example of a film deposition method according to the first embodiment. The film deposition method according to the first embodiment, as shown in Figure 1, includes steps S1, S2, S3, S4, and S5. The sequence of steps S1 to S4 is repeated for a desired number of cycles, with step S5 performed in each cycle. Step S1 is the step of supplying a raw material gas (MO gas) containing an organometallic precursor into the processing container. MO gas is produced, for example, by vaporizing a liquid or solid organometallic precursor. Step S2 is the step of purging the processing container after step S1 to discharge any remaining gas. Step S3 is the step of supplying an oxidizing agent into the processing container after step S2. Step S4 is the step of purging the processing container after step S3 to discharge any remaining gas. Step S5 is the step of supplying a reducing gas containing hydrogen, for example, hydrogen gas ( H2 gas), into the processing container. In the example in Figure 1, the supply of the reducing gas containing hydrogen in step S5 is shown to be performed simultaneously with the supply of MO gas in step S1. Note that in the example in Figure 1, the supply period of the organometallic precursor and the supply period of the reducing gas containing hydrogen are shown to be completely coincidental, but "simultaneously" also includes cases where some of these periods coincide. Figure 2 is a timing chart showing the gas supply timing in another example of the film deposition method according to the first embodiment. This example shows a case where step S5 is performed sequentially after step S1. Steps S1 to S4 are the same as in the example in Figure 1. The sequences in Figures 1 and 2 will be explained in more detail below. In step S1, MO gas is supplied into the processing container to adsorb the MO gas onto the