JP2023065305A - Deposition method and deposition system - Google Patents

Abstract

To improve the embedding performance of silicon-containing films into recesses formed in the substrate.SOLUTION: A deposition method is provided comprising the steps of: (a) preparing a substrate having a recess in a processing vessel; (b) activating a gas containing silicon by plasma and supplying the gas to the substrate to form a silicon-containing film on the substrate; (c) partially modifying the silicon-containing film after the silicon-containing film closes an opening in the recess; and (d) selectively etching the modified silicon-containing film.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a film forming method and a film forming system.

With the miniaturization of semiconductor devices, there is a demand for burying high-quality films that do not generate voids or seams in recesses having high aspect ratios.

For example, Patent Document 1 discloses a process of forming a silicon oxide film on a substrate by supplying a silicon-containing gas and an oxygen-containing gas, and supplying a hydrofluoric acid gas and an ammonia gas to etch the silicon oxide film. and an etching step, wherein the film forming step and the etching step are alternately repeated.

For example, in Japanese Unexamined Patent Application Publication No. 2002-100001, in the first step, a film formation process for depositing an insulating film on a substrate and wiring and an etching process for sputter etching with Ar and ions are performed simultaneously, thereby forming voids between wirings. Then, in a second step, the insulating film above the wiring and the insulating film between the wires are selectively etched to flatten the insulating film above the wiring and form openings between the wires. A deposition method is disclosed that repeats the steps.

JP 2012-199306 A JP-A-2003-37103 JP 2007-180418 A

The present disclosure provides a technology capable of enhancing the embedding performance of a silicon-containing film into a concave portion formed in a substrate.

According to one aspect of the present disclosure, the steps of (a) preparing a substrate having a recess in a processing container, and (b) activating a gas containing silicon with plasma and supplying it to the substrate to form a silicon-containing film (c) partially modifying the silicon-containing film after the silicon-containing film closes the opening of the recess; and (d) modifying the silicon-containing film. and selectively etching the film.

According to one aspect, it is possible to improve the embedding performance of the silicon-containing film into the concave portion formed in the substrate.

4 is a flowchart showing a film forming method ST according to the embodiment; Explanatory drawing of the film-forming method which concerns on embodiment. FIG. 4 is a diagram showing the relationship between film formation time and film thickness according to the embodiment; FIG. 4 is a diagram showing the relationship between film formation time and pressure according to the embodiment; FIG. 5 is a diagram showing the relationship between film formation time and gas flow rate ratio according to the embodiment; The figure which shows the structural example of the film-forming system which concerns on embodiment. The figure which shows the structural example of the film-forming apparatus which concerns on embodiment. The figure which shows the structural example of the other processing apparatus which concerns on embodiment.

Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals, and redundant description may be omitted.

[Film formation method ST]
2. Description of the Related Art With the miniaturization of semiconductor devices in the steps of semiconductor manufacturing processes, there is a demand for embedding high-quality films that do not generate voids or seams in recesses having high aspect ratios. Conventional Atomic Layer Deposition (ALD) has problems such as low throughput, occurrence of seams and voids, shape deformation of concave portions in post-processes, deterioration of film electrical properties, and the like.

In addition, in the conventional High-Density Plasma Chemical Vapor Deposition (HDP (High Density Plasma) CVD), the CD (Critical Dimension) is reduced, the performance of burying the film in the concave portion is deteriorated due to the high aspect ratio, and the ion implantation causes There are problems such as deformation of the substrate structure and deterioration of the film quality.

In addition, in the conventional technology of Flowable Chemical Vapor Deposition (FCVD), there are problems such as the complication of the film forming process of the fluid film and the cure treatment process, and the deterioration of the electrical characteristics due to the film quality gradient in the depth direction of the film. be done.

The present disclosure proposes a film formation method capable of solving the above problems and improving the embedding performance of a silicon-containing film in a concave portion formed in a substrate.

FIG. 1 is a flow chart showing a film forming method ST according to an embodiment. FIG. 2 is an explanatory diagram of the film forming method ST according to the embodiment. A film formation method ST of the present disclosure forms a silicon-containing film in a concave portion formed in a substrate W, an example of which is a wafer (semiconductor wafer).

(Substrate preparation step S1)
First, in the substrate preparation step S1 of FIG. 1, a step of providing a substrate W in a processing container of a processing apparatus is performed. FIG. 2( a ) shows an example of a substrate W having recesses 114 . The substrate W has a plurality of recesses 114 on the silicon substrate 110 . The recess 114 in the substrate W has a trench structure and has a top surface 112 , a bottom surface 116 and side surfaces 118 . The recess 114 may be a hole or a line.

(Film formation step S3)
Next, in the film formation step S3 of FIG. 1, a silicon-containing film is deposited in the concave portion 114 of the substrate W. In the present disclosure, a silicon-containing film is formed by CVD. Specifically, a silicon-containing gas is activated by plasma and supplied to the substrate W to form a silicon-containing film on the substrate W. FIG.

Here, a silicon nitride film (SiN) is deposited as an example of the silicon-containing film. In this case, a processing gas containing a silicon-containing gas and a nitrogen-containing gas is supplied into the processing chamber of the processing apparatus to generate plasma, and the gas species activated by the plasma are chemically reacted to form a silicon nitride film. to form The silicon-containing gas may be silane ( _SiH4 ) gas, and the nitrogen-containing gas may be ammonia ( _NH3 ) gas. However, the types of silicon-containing gas and nitrogen-containing gas are not limited to these. For example, the nitrogen-containing gas may be nitrogen ( _N2 ) gas. In the film forming step S3, the film is formed under the condition that the silicon nitride film is preferentially formed near the upper surface 112 of the recess 114 and the bottom surface 116 of the recess 114, and the silicon nitride film formed near the upper surface 112 of the recess 114 is formed. The membrane closes the opening of the recess 114 . The process conditions of the film-forming process S3 are shown below.
<Process conditions for film formation step S3>
Deposition gas SiH ₄ , N ₂ and Ar
Pressure 5Pa to 50Pa
Plasma power 500W~4500W
SiH ₄ gas, NH ₃ gas, and Ar gas are supplied into the processing chamber, activated by plasma, and supplied to the substrate W, thereby forming a silicon nitride film on the substrate W. FIG.

FIG. 2B shows a state in which a silicon nitride film 120 is deposited on the bottom surface 116 and top surface 112 of the recess 114 and the opening of the recess 114 is blocked by the silicon nitride film 120 . In the film forming step S3, film formation is performed under process conditions such that the silicon nitride film 120 is preferentially formed on the top surface 112 and the bottom surface 116 of the recess, and the silicon nitride film 120 is not formed on the side surface 118 as much as possible. In other words, the film is not formed conformally in the film forming step S3. As such process conditions, for example, the pressure inside the processing container is increased. In addition, for example, the flow rate of SiH ₄ gas and/or NH ₃ gas is increased relative to the total flow rate of SiH ₄ gas, NH ₃ gas, and mixed gas such as Ar gas supplied into the processing chamber.

In FIG. 2B, the silicon nitride film 120 is deposited on the bottom surface 116 and the top surface 112 of the recess 114, the silicon nitride film 120 deposited on the top surface 112 becomes mushroom-like, and contacts the adjacent silicon nitride film 120 to form the recess. 114 is shown closed. When the silicon nitride film 120 is preferentially formed until the opening of the recess 114 is closed, the silicon nitride film 120 is also formed on the bottom surface 116 of the recess 114 and the void 115 is formed thereabove.

(Oxidation step S5 (reforming step))
Next, in the oxidation step S5 of FIG. 1, the silicon nitride film 120 including the silicon nitride film 120 blocking the opening of the recess 114 is partially oxidized. The oxidation step S5 is an example of a step of partially modifying the silicon nitride film 120 .

The oxidation step S5 may partially oxidize the silicon nitride film 120 . Process conditions for the oxidation step S5 when the silicon nitride film 120 is oxidized are shown below. The oxidation step S5 may use plasma as described below, or may not use plasma.
<Process conditions of oxidation step S5>
Oxidizing gas _O3 , or _O2 , or nitrous oxide ( _N2O )
Presence or absence of plasma In the case of _O3 , the substrate is exposed to _O3 gas (no plasma is used).
For O ₂ or N ₂ O plasma activation (using plasma)
Mounting table (substrate) temperature 200°C to 500°C
Pressure 5Pa to 400Pa
Plasma power 500W to 4500W (when using plasma)

As a result, the silicon nitride film 120 deposited on the upper surface 112 is partially oxidized into a silicon oxide (SiOx) film 121 . This process is continued until at least the portion of the silicon nitride film 120 blocking the opening of the recess 114 is oxidized. FIG. 2C shows a state in which the silicon nitride film 120 is partially oxidized and modified (degraded) into a silicon oxide film 121 . The silicon nitride film 120 blocking the opening of the recess 114 is partially oxidized and reformed into a silicon oxide film 121 . Since the silicon nitride film formed in the vicinity of the upper surface 112 is thick, the oxidation step S5 is preferably performed under conditions of, for example, a high pressure and a large flow rate of the oxidizing gas. Also, for example, when plasma is used, conditions of high pressure and high plasma power are suitable. Also, the processing temperature is preferably a temperature equal to or higher than that of the film forming step S3.

The oxidized portion is the silicon nitride film 120 in the vicinity of the upper surface 112 (for example, a layer above the upper surface 112), and the silicon nitride film 120 formed at the bottom of the recess 114 blocks the opening of the recess 114. Oxidation by S5 can be avoided. Therefore, according to this process, the silicon nitride film 120 blocking the opening of the recess 114 is reformed into the silicon oxide film 121 while protecting the silicon nitride film 120 at the bottom of the recess 114 (without reforming it). can be qualitative. In this manner, only the silicon nitride film 120 near the upper surface 112 of the recess 114 is reformed (oxidized) into a silicon oxide film 121 . This facilitates selective etching of the silicon oxide film 121 blocking the opening of the recess 114 in the etching step S7, which will be described later.

(Etching step S7 (first etching step))
Next, in the etching step S7 of FIG. 1, the modified silicon oxide film 121 is selectively etched. In the case of the silicon nitride film 120 and the silicon oxide film 121, the silicon oxide film 121 is easily etched under the following process conditions. Thereby, the silicon oxide film 121 can be selectively etched with respect to the silicon nitride film 120 and the silicon oxide film 121 can be selectively removed. As a result, the silicon nitride film 120 on the bottom surface 116 of the recess 114 is not removed even by this etching step S7.

By removing the silicon oxide film 121, the opening of the recess 114 is formed again. FIG. 2(d) shows a state where the silicon oxide film 121 is removed, the opening of the recess 114 is opened again, and the silicon nitride film 120 which is not oxidized remains. The etching step S7 removes the silicon oxide film 121 without using plasma. Process conditions for the etching step S7 are shown below. These etching steps are also described in detail in Patent Document 3.
<Process conditions of etching step S7>
COR etching gas NH ₃ and hydrogen fluoride (HF) COR process Mounting table (substrate) temperature 20°C to 90°C
COR process pressure 5Pa to 133Pa

Thereby, the silicon oxide film 121 is selectively etched with respect to the silicon nitride film 120 . The etching process S7 includes a COR (Chemical Oxide Remover) process and a PHT (Post Heat Treatment) process. In the COR process, a fluorine-containing gas and a nitrogen-containing gas are supplied to the substrate W, and the fluorine-containing gas, the nitrogen-containing gas, and the silicon oxide film 121 are reacted to form an easily vaporizable substance. In the PHT process, the formed vaporizable substance is heated to be vaporized and removed. For example, by using NH ₃ gas and HF gas as reaction gases in the COR process and the PHT process, the silicon oxide film 121 is removed using the following chemical reaction. An example of a fluorine-containing gas is HF gas, and an example of a nitrogen-containing gas is _NH3 gas, but the present invention is not limited to these.

In the COR process, the silicon oxide film 121 is changed into an easily vaporizable substance without using plasma as shown in the following chemical reaction formula. By not using plasma, it is possible to reduce deterioration or damage of the silicon nitride film 120 formed in the recess 114 .

<Chemical Reaction Formula of COR Process / Formation of Vaporizable Products>
SiO ₂ (Solid)+2NH ₃ (gas)+6HF (gas)→(NH ₄ ) ₂ SiF ₆ (Solid, easily vaporizable product)+2H ₂ O (gas)

When the silicon oxide film 121 is exposed to NH ₃ gas and HF gas, it turns into ammonium silicofluoride ((NH ₄ ) ₂ SiF ₆ ) as an easily vaporizable product.

In the PHT process, the ammonium silicofluoride formed by the COR process is heat-treated as shown in the following chemical reaction formula to vaporize and remove the ammonium silicofluoride into SiF ₄ , HF and NH ₃ . In order to vaporize ammonium silicofluoride in this manner, it is preferable to control the temperature of the mounting table on which the substrate is placed or the temperature of the substrate to 50° C. or higher in the PHT process. Alternatively, it may be vaporized by supplying a high-temperature heating gas as described in Patent Document 3.

<Chemical Reaction Formula of PHT Process>
( _NH4 ) _2SiF6- > _SiF4 ↑+ _2NH3 ↑+ _2HF ↑
Thereby, the silicon oxide film 121 above the upper surface 112 including the silicon nitride film 120 blocking the opening of the recess 114 can be removed without using plasma. As a result, the opening of the recess 114 is opened again, making it possible to form the silicon nitride film 120 bottom-up from the bottom surface 116 in the next film forming step S3.

(Embedding determination step S9)
Next, in the embedding determination step S9 in FIG. 1, it is determined whether the recess 114 is filled with the silicon nitride film 120 or not. The processes shown in steps S3 to S7 are performed until it is determined that the recess 114 is filled with the silicon nitride film 120. Next, as shown in FIG. As a result, the processes of film formation step S3, oxidation step S5, and etching step S7 included in steps S3 to S7 are repeated. In FIG. 2(e), it is determined that the gap 115 is formed and the recess 114 is not completely filled with the silicon nitride film 120 ("No" in step S9), and the next film formation step S3 is performed. Indicates the state after. Since the opening of the recess 114 is opened again in the etching step S7, the silicon nitride film 120 is deposited bottom-up from the bottom surface of the recess 114 in the next film forming step S3.

In other words, the film formation step S3, the oxidation step S5, and the etching step S7 are repeated in this order until the silicon nitride film 120 fills the recess 114. As shown in FIG.

Further, after the silicon nitride film 120 is formed in the film formation step S3, the oxidation step S5 and the etching step S7 may be repeated one or more times. As a result, the opening of the recess 114 can be opened with good controllability.

Further, a step (second etching step) of etching the silicon-containing film remaining on the upper portion and sidewall portion of the recess 114 after the etching step S7 (first etching step) may be included. For example, as shown in FIG. 2D, after the etching step S7, the silicon nitride film 120 may remain on the upper portion and side wall portions of the recess 114 in some cases. If the silicon nitride film 120 is formed on the bottom of the recess 114 in this state, the opening of the recess 114 will be narrowed, and there is a possibility that the burying property will be deteriorated. Therefore, after the etching step S7, the silicon nitride film 120 remaining on the upper portion and sidewall portion of the recess 114 is selectively etched. Specifically, etching is performed using a COR process and a PHT process in the same manner as the etching process S7. In the COR process, the pressure, gas flow ratio, processing time, etc. are adjusted so that the silicon nitride film 120 can be selectively etched. As a result, the silicon nitride film 120 on the upper and side walls of the recess 114 can be removed as shown in FIG.

Also, the COR process and the PHT process of the second etching process may be repeated once or more. As a result, the opening of the recess 114 can be opened with good controllability.

After the etching step S7, the opening of the recess 114 is opened again, and the silicon nitride film 120 formed on the bottom surface 116 is exposed. A step of reforming by (second reforming) may be further performed. After selectively etching the silicon nitride film 120 remaining on the upper portion and sidewall portion of the recess 114 after the etching step S7, the second modification may be further performed. Thereby, the film quality of the formed silicon nitride film 120 can be improved. Further, a step of densifying the film by heat treatment may be further performed. As a result, a dense silicon nitride film 120 is formed and the film quality is improved.

Further, in the film formation step S3 of FIG. 1, it is determined whether or not all the openings of the plurality of recesses 114 are closed by the silicon nitride film 120, and the film formation is continued until it is determined that all the openings of the recesses 114 are closed. A determination step may be included followed by step S3.

As a method of determining whether or not the opening of the recess 114 is closed, it may be determined by optically measuring the cross-sectional shape of the silicon nitride film 120 deposited on the upper surface 112 . Depending on whether the silicon nitride film 120 on the upper surface 112 is completely blocked or not completely blocked, the state of reflection of light applied to the silicon nitride film 120 deposited on the upper surface 112 changes. Whether or not the opening is blocked by the silicon nitride film 120 may be determined based on a certain point of change in the light reflection state. However, the determination method is not limited to this, and other methods can be used. For example, the time until the silicon nitride film 120 deposited on the upper surface 112 closes is measured in advance as the film formation control time and stored in the storage unit. The next oxidation step S5 may be started after the film formation control time has elapsed since the film formation step S3 was started.

Further, the oxidation step S5 of FIG. 1 may include a determination step of determining whether the silicon nitride film 120 blocking the opening of the recess 114 has been oxidized. The oxidation step S5 is performed until it is determined that the silicon nitride film 120 blocking the opening of the recess 114 has been reformed into the silicon oxide film 121 . As a result, the oxidation step S5 is performed until the silicon nitride film 120 blocking the opening of the recess 114 is oxidized to the silicon oxide film 121. Next, as shown in FIG.

As a method for determining whether the silicon nitride film 120 blocking the opening of the recess 114 has been modified into the silicon oxide film 121, the shape of the cross section of the silicon nitride film 120 is measured by an optical method. You may Depending on whether the silicon nitride film 120 blocking the opening of the recess 114 is oxidized or whether there is a part of the silicon nitride film 120 which is not completely oxidized and there is a portion of the silicon nitride film 120, the reflected state of the irradiated light changes. It may be determined that the silicon nitride film 120 blocking the opening of the recess 114 has been reformed into the silicon oxide film 121 at a certain change point of the light reflection state. However, other methods can be used without being limited to this determination method. For example, the time until the silicon nitride film 120 blocking the opening of the recess 114 is reformed into the silicon oxide film 121 is measured in advance as a reformation control time and stored in the storage unit. After the oxidation step S5 is started, the next etching step S7 may be started when the modification control time elapses. The modification control time varies depending on the temperature of the mounting table (substrate). Therefore, the reforming control time corresponding to the control temperature of the mounting table (substrate) may be measured in advance and stored in the storage unit.

Further, the embedding determining step S9 may include a determining step of determining whether the recess 114 has been completely embedded with the silicon nitride film 120 . As a determination method, the time until the concave portion 114 is filled with the silicon nitride film 120 may be measured in advance and stored, and the measured time may be used as the filling determination time. Alternatively, the cross section of the silicon nitride film 120 in the recess 114 may be optically determined to detect the end point indicating the completion of filling with the silicon nitride film 120, or other methods may be used.

[effect]
The features and effects of the film forming method ST described above are as follows.
<Features>
1. A silicon nitride film is formed so as to close the opening of the recess 114 during the film forming process.
2. A layer above the upper surface containing the closed silicon nitride film is selectively oxidized.
3. The oxidized silicon oxide film is selectively etched with respect to the silicon nitride film.
4.1. ~3. (film formation step S3, oxidation step S5, etching step S7) are repeated until the trench structure (recess) is filled.

As a result, it is possible to suppress the occurrence of seams and voids and embed the high-quality silicon nitride film 120 in the concave portion having a high aspect ratio.

In the film formation method ST of FIG. 1, an example of embedding a silicon nitride film in the concave portion 114 of the trench structure was given as an example of the silicon-containing film, but the silicon-containing film may be a film containing silicon and nitrogen. . The film containing silicon and nitrogen may be any one of SiN film, SiCN film, SiBN film, SiON film, and SiOCN film. Also, the silicon-containing film may be a Si film. Both films are oxidized in the oxidation step S5. For example, when the silicon-containing film is a Si film, the Si film is oxidized into a SiO film in the oxidation step S5. Also in this case, the SiO film can be selectively etched with respect to the Si film in the etching step S7.

When the silicon-containing film is a SiON film, the SiON film is oxidized to form a SiO film. In addition, even if there is a part of the SiO film in which N remains as SiON, the amount of N component in the film is small if the film is sufficiently modified. can be obtained, and the SiO film can be selectively etched.

[Deposition time and film thickness]
FIG. 3 is a diagram showing the relationship between the time (film formation time) of the film formation step S3 and the film thickness, and is an experimental result of forming a silicon nitride film by the film formation method ST. The horizontal axis of FIG. 3 indicates the elapsed time from the start of the film forming step S3 as "film formation time (sec)", and the vertical axis indicates the thickness of the silicon nitride film 120 formed in the recess 114 as "Thickness (Å)". ”. "Top" indicated by ◯ indicates the thickness (film thickness) of the thickest portion of the silicon nitride film 120 deposited from the upper surface 112 of the recess 114 from the upper surface 112 . "Bottom" indicated by ● indicates the thickness (film thickness) from the bottom surface 116 of the thickest portion of the silicon nitride film 120 deposited on the bottom surface 116 of the recess 114 . The process conditions for this experiment are as follows.
<Process conditions>
Deposition gas (flow ratio) SiH ₄ , NH ₃ and Ar (flow ratio SiH ₄ :NH ₃ =20:10 to 20:20)
Pressure 5Pa to 50Pa
Temperature 200℃～600℃
Power 1500W~4500W

According to the experimental results shown in FIG. 3, the film thickness of "Top" was thicker than that of "Bottom" regardless of the film formation time. In addition, the longer the film formation time, the greater the difference between the "Top" film thickness and the "Bottom" film thickness, and the faster the growth speed of the "Top" silicon nitride film relative to the "Bottom" silicon nitride film. rice field.

[Deposition time and pressure]
If the film thickness of "Top" shown in FIG. 3 can be increased in a short period of time, the opening of the concave portion 114 can be closed with the silicon-containing film in a short period of time. As a result, it is possible to increase the operation rate of the processing apparatus that performs the film forming step S3 and improve the throughput, which is advantageous.

Therefore, the range of the pressure and/or the gas flow rate ratio should be controlled to an optimum value so that the film thickness of the "top" increases in a short time and the opening of the recess 114 can be blocked by the silicon-containing film in a short time. is preferred.

FIG. 4 is a diagram showing the relationship between film formation time and pressure according to the embodiment. The horizontal axis of FIG. 4 indicates the film formation time, and the vertical axis indicates the pressure inside the processing chamber of the processing apparatus that performs the film forming step S3. When the film formation time is divided into step 1, step 2, and step 3, in the initial step step 1 of the film formation step S3, a preset pressure P1 is set and controlled to maintain this. In the intermediate process step2, the pressure is controlled to be a pressure P2 higher than the pressure P1. In the latter stage step 3 when the pressure reaches the pressure P2, the pressure is controlled to be maintained at the pressure P2.

In such control, the film formation time is divided into a plurality of steps, and the pressure is controlled step by step according to the initial, middle, and late stages of the film formation. For example, after the silicon-containing film is formed on the bottom surface 116 to some extent in the initial step 1, the pressure condition is changed to grow the silicon-containing film above the upper surface 112 faster in the middle-term step 2, and the pressure is controlled to the target pressure. After controlling to the target pressure in the middle process step2, the target pressure is maintained in the latter process step3. The pressure is thus controlled stepwise. As a result, the opening of the recess 114 can be closed more quickly by the silicon-containing film while promoting the filling of the bottom surface of the recess 114 with the silicon-containing film. However, the step of forming the silicon-containing film is not limited to controlling the pressure so that it changes stepwise, but may also control the pressure so that it changes continuously.

[Deposition time and gas flow ratio]
In the film forming step S3, the flow ratio of the silicon-containing gas may be controlled stepwise. FIG. 5 is a diagram showing the relationship between film formation time and gas flow rate ratio according to the embodiment. The horizontal axis of FIG. 5 indicates the film formation time, and the vertical axis indicates the flow rate of NH ₃ gas (and/or N ₂ gas) relative to SiH ₄ gas, for example, as the gas supplied into the processing container in which the film formation step S3 is performed. Show the ratio. When the film formation time is divided into step 1, step 2, and step 3, in the initial step step 1 of the film formation process S3, the flow rate ratio of _NH3 gas (and/or _N2 gas) to _SiH4 gas is set to the preset flow rate ratio R1. and control to maintain the flow rate ratio R1. In the intermediate process step2, the flow ratio is controlled to be a flow ratio R2 higher than the flow ratio R1. In the later step step 3 when the flow rate ratio of the gas reaches the flow rate ratio R2, control is performed so as to maintain the flow rate ratio R2. By controlling the flow rate ratio of a plurality of gases containing silicon stepwise in this manner, the opening of the recess 114 can be closed more quickly by the silicon-containing film of the recess 114 . However, the step of forming the silicon-containing film is not limited to controlling the flow rate ratio to change stepwise, and may be controlled to change the flow rate ratio continuously. Also, the flow ratio R1 and the flow ratio R2 are not limited to the flow ratio of _NH3 gas (and/or _N2 gas) to _SiH4 gas. For example, it may be the flow rate ratio of SiH ₄ gas to the total mixed gas containing SiH ₄ gas (all gases supplied).

[Deposition system]
FIG. 6 is a diagram illustrating a configuration example of a film forming system according to the embodiment; The film formation system includes a processing apparatus that executes the film formation method ST of the present disclosure. However, the configuration of the film forming system in FIG. 6 is an example, and other configurations are possible.

The film forming system includes processing apparatuses 101 to 104, a vacuum transfer chamber 200, load lock chambers 301 to 303, an atmospheric transfer chamber 400, load ports 501 to 504, and a controller 600.

The processing apparatuses 101 to 104 are connected to the vacuum transfer chamber 200 via gate valves G11 to G14, respectively. The insides of the processing apparatuses 101 to 104 are depressurized to a predetermined vacuum atmosphere, and the substrate W is subjected to a desired process therein. The processing apparatus 101 is an example of a first processing apparatus configured to perform the film formation step S3 of FIG. The processing apparatus 102 is an example of a second processing apparatus configured to perform the oxidation step S5 (modifying step) of FIG. 1 and partially oxidize (modify) the silicon-containing film formed in the concave portion. is. The processing apparatuses 103 and 104 are an example of a third processing apparatus configured to perform the etching step S7 of FIG. 1 and selectively etch the oxidized (modified) silicon-containing film. For example, processor 103 performs the COR process and processor 104 performs the PHT process. The film forming step S3 and the oxidation step S5 may be performed in the processing apparatus 101 . In this case, the processing device 102 may be a device that performs the same process as the processing device 101, or may be a device that performs a different process. A configuration example of the processing device 101 will be described later with reference to FIG.

The inside of the vacuum transfer chamber 200 is depressurized to a predetermined vacuum atmosphere. The vacuum transfer chamber 200 is provided with a transfer mechanism 201 capable of transferring the substrate W under reduced pressure. The transport mechanism 201 transports the substrates W to the processing apparatuses 101-104 and the load lock chambers 301-303. The transport mechanism 201 has, for example, two transport arms. However, the number of transfer arms may be one.

The load-lock chambers 301-303 are connected to the vacuum transfer chamber 200 via gate valves G21-G23, respectively, and are connected to the atmospheric transfer chamber 400 via gate valves G31-G33. The load-lock chambers 301 to 303 can be switched between an atmospheric atmosphere and a vacuum atmosphere.

The inside of the atmospheric transfer chamber 400 has an atmospheric atmosphere, and for example, a clean air downflow is formed. An aligner (not shown) that aligns the substrate W is provided in the atmospheric transfer chamber 400 . A transport mechanism 402 is provided in the atmospheric transport chamber 400 . The transport mechanism 402 has, for example, one transport arm. However, there may be two or more transfer arms. The transport mechanism 402 transports the substrate W to the load lock chambers 301 to 303, the carrier C of the load ports 501 to 504 described later, and the aligner.

The load ports 501 to 504 are provided on the walls of the long sides of the atmospheric transfer chamber 400 . Load ports 501 to 504 are attached with carriers C containing substrates W or empty carriers C via gate valves G41 to G44. As carrier C, for example, a FOUP (Front Opening Unified Pod) can be used.

The controller 600 controls each part of the film forming system. For example, the control unit 600 controls the operations of the processing apparatuses 101 to 104, the operations of the transport mechanisms 201 and 402, the opening and closing of the gate valves G11 to G14, G21 to G23, G31 to G33, and G41 to G44, and the load lock chambers 301 to 303. , etc., is executed. Control unit 600 may be, for example, a computer.

[Deposition equipment]
FIG. 7 is a diagram showing a configuration example of the film forming apparatus 100 according to the embodiment. The film-forming apparatus 100 is an apparatus for performing the film-forming step S3 to form a silicon-containing film on the concave portion of the substrate W within the processing vessel 1 in a decompressed state, and is an example of the processing apparatus 101 in FIG. The film forming apparatus 100 may be an apparatus that performs the oxidation step S5 following the film forming step S3. That is, the oxidation step S5 may be performed by the processing apparatus 101 having the film forming apparatus 100 of FIG.

However, the configuration of the film forming apparatus 100 in FIG. 7 is an example, and the film forming apparatus includes Capacitively Coupled Plasma (CCP), Inductively Coupled Plasma (ICP), Micro Surface Wave Plasma, Electron Cyclotron Resonance Plasma (ECR), Helicon Wave Any type of Plasma (HWP) plasma processing apparatus is applicable. Even a thermal CVD apparatus that does not use plasma can be applied as long as the process conditions are such that the opening is closed by film formation. In addition, the film forming apparatus can be applied to any of a single-wafer apparatus for processing substrates one by one, a batch apparatus and a semi-batch apparatus for collectively processing a plurality of substrates.

The film forming apparatus 100 has a processing container 1 formed in a substantially cylindrical shape from aluminum or the like whose inner wall surface is anodized. The processing container 1 is grounded. A susceptor 2 is provided inside the processing container 1 . The susceptor 2 is supported by a substantially cylindrical support member 3 provided in the central lower portion of the processing container 1 . The susceptor 2 is a mounting table (stage) for horizontally supporting the substrate W, and is made of, for example, a ceramic material such as aluminum nitride (AlN), or a metal material such as aluminum or nickel alloy. Susceptor 2 is grounded via support member 3 .

A guide ring 4 for guiding the substrate W is provided on the outer edge of the susceptor 2 . A heater 5 made of a high melting point metal such as molybdenum is embedded in the susceptor 2 . A heater power supply 6 is connected to the heater 5 . The heater 5 heats the substrate W supported by the susceptor 2 to a predetermined temperature with power supplied from the heater power source 6 .

A shower head 10 is provided on the ceiling wall 1 a of the processing container 1 with an insulating member 9 interposed therebetween. The showerhead 10 in this embodiment is a premix type showerhead and has a base member 11 and a shower plate 12 . The outer periphery of shower plate 12 is fixed to base member 11 .

The shower plate 12 has a flange shape, and a concave portion is formed inside the shower plate 12 . That is, a gas diffusion space 14 is formed between the base member 11 and the shower plate 12 . A flange portion 11a is formed on the outer peripheral portion of the base member 11, and the base member 11 is supported by the insulating member 9 via the flange portion 11a.

A plurality of gas ejection holes 15 are formed in the shower plate 12 . A gas introduction hole 16 is formed near the approximate center of the base member 11 . The gas introduction hole 16 is connected to the gas supply mechanism 20 via a pipe 30 .

The gas supply mechanism 20 has a silicon-containing gas supply source 21 , a rare gas supply source 22 , and a nitrogen-containing gas supply source 23 . In this embodiment, the silicon-containing gas is, for example, _SiH4 gas. Further, in the present embodiment, the rare gas is Ar gas, for example. Moreover, in this embodiment, the nitrogen-containing gas is, for example, ammonia (NH ₃ ) gas.

Supply source 21 is connected to piping 30 via valve 28 , mass flow controller (MFC) 27 and valve 28 . Source 22 is connected to piping 30 via valve 28 , mass flow controller (MFC) 27 and valve 28 . Supply source 23 is connected to piping 30 via valve 28 , mass flow controller (MFC) 27 and valve 28 . The processing gas supplied in the gas diffusion space 14 through the pipe 30 diffuses in the gas diffusion space 14 and is discharged into the processing container 1 through the gas discharge holes 15 in a shower-like manner.

An RF (Radio Frequency) power supply 45 is connected to the base member 11 via a matching device 44 . The RF power supply 45 supplies RF power for plasma generation to the base member 11 through the matching device 44 . RF power supplied to the base member 11 is radiated into the processing container 1 via the intermediate member 13 and the shower plate 12 . The RF power radiated into the processing container 1 turns the processing gas supplied into the processing container 1 into plasma. In this embodiment, the showerhead 10 also functions as the upper electrode of the parallel plate electrodes. On the other hand, the susceptor 2 also functions as a lower electrode of the parallel plate electrodes.

A substantially circular opening 50 is formed in a substantially central portion of the bottom wall 1 b of the processing container 1 . An exhaust chamber 51 is provided in the opening 50 of the bottom wall 1b so as to cover the opening 50 and protrude downward. The exhaust chamber 51 is grounded via the processing container 1 . An exhaust pipe 52 is connected to a side wall of the exhaust chamber 51 . An exhaust device 53 including a vacuum pump is connected to the exhaust pipe 52 . The inside of the processing container 1 can be decompressed to a predetermined degree of vacuum by the exhaust device 53 .

The susceptor 2 is provided with a plurality of (for example, three) lift pins 54 for lifting and lowering the substrate W so as to protrude from the surface of the susceptor 2 . A plurality of lift pins 54 are supported by support plates 55 . The support plate 55 is moved up and down by driving the drive mechanism 56 . As the support plate 55 moves up and down, the plurality of lift pins 54 move up and down.

A side wall of the processing container 1 is provided with a transfer port 57 for transferring the substrate W between the processing container 1 and a substrate transfer chamber (not shown) provided adjacent to the processing container 1 . The transfer port 57 is opened and closed by a gate valve 58 .

The film forming apparatus 100 includes a control device 60 . The control device 60 is a computer, for example, and has a control section 61 and a storage section 62 . The storage unit 62 pre-stores programs and the like for controlling various processes executed in the film forming apparatus 100 . The control unit 61 controls each unit of the film forming apparatus 100 by reading out and executing programs stored in the storage unit 62 .

Note that the programs pre-stored in the storage unit 62 may be recorded in a computer-readable storage medium and installed in the storage unit 62 from the storage medium. Examples of computer-readable storage media include hard disks (HD), flexible disks (FD), compact disks (CD), magnet optical disks (MO), memory cards, and the like.

Further, the control device 60 includes a keyboard for inputting commands for the operator to manage the film forming apparatus 100, a display for visualizing and displaying the operating status of the film forming apparatus 100, and the like. A user interface 63 is connected.

In the system of FIG. 6, the processing apparatuses 101 to 104 have been described as processing apparatuses corresponding to the film forming process, the reforming process, the COR process, and the PHT process, respectively, but this is not the only option. For example, as shown in FIG. 8, a plurality of substrates W may be processed within one processing apparatus. For example, the processing apparatus shown in FIG. 8 has a plurality of mounting tables 801-804 in a processing chamber, and a plurality of substrates W (for example, four) are mounted on each of the mounting tables 801-804. Also, a plurality of processing spaces 805 to 808 corresponding to the plurality of mounting tables 801 to 804 are provided. Then, the silicon-containing film is embedded in the concave portion formed in the substrate W by performing each step of the film formation step, the modification step, the COR step, and the PHT step in each processing space. In this way, a single apparatus can perform a plurality of processes on a plurality of substrates W, thereby improving productivity. Note that the processing space 805 is an example of a first processing space in which the film formation process is performed. Processing space 806 is an example of a second processing space in which the reforming process is performed. Processing space 807 is an example of a third processing space in which a COR process is performed. Processing space 808 is an example of a fourth processing space in which the PHT process is performed.

As described above, according to the film forming method and film forming system of the present embodiment, it is possible to improve the embedding performance of the silicon-containing film into the concave portion formed in the substrate.

The film forming method and film forming system according to the embodiments disclosed this time should be considered as examples and not restrictive in all respects. Embodiments can be modified and improved in various ways without departing from the scope and spirit of the appended claims. The items described in the above multiple embodiments can take other configurations within a consistent range, and can be combined within a consistent range.

114 recess 120 silicon nitride film 121 silicon oxide film ST film formation method S3 film formation step S5 oxidation step S7 etching step W substrate

Claims (25)

(a) providing a substrate having recesses in a processing vessel;
(b) activating a silicon-containing gas with plasma and supplying it to a substrate to form a silicon-containing film on the substrate;
(c) partially modifying the silicon-containing film after the silicon-containing film closes the opening of the recess;
(d) selectively etching the modified silicon-containing film;
A film forming method comprising: The step (b) of forming a silicon-containing film, the step (c) of modifying the silicon-containing film, and the step of (d) etching the silicon-containing film are performed in this order one or more times. conduct,
The film forming method according to claim 1 . After the step (b) of forming the silicon-containing film, the step (c) of modifying the silicon-containing film and the step (d) of etching the silicon-containing film are performed once in this order. do more
The film forming method according to claim 1 . The step of forming the silicon-containing film in (b) comprises stepwise or continuously controlling the pressure in the processing container of the processing apparatus for forming the silicon-containing film.
The film forming method according to any one of claims 1 to 3. The step of forming a silicon-containing film in (b) includes the step of (b-1) controlling the pressure in a processing container of a processing apparatus for forming the silicon-containing film to a first pressure;
(b-2) controlling the pressure in the processing container of the processing apparatus for forming the silicon-containing film to a second pressure higher than the first pressure;
The film forming method according to claim 4 . In the step of forming the silicon-containing film in (b), the flow rate ratio of the silicon-containing gas to a plurality of mixed gases containing the silicon-containing gas is controlled stepwise or continuously.
The film forming method according to any one of claims 1 to 5. The step of forming the silicon-containing film of (b) includes:
(b-3) controlling the flow ratio of the silicon-containing gas to a plurality of mixed gases containing the silicon-containing gas to a first flow ratio;
(b-2) controlling the flow rate ratio of the silicon-containing gas to a plurality of mixed gases containing the silicon-containing gas to a second flow rate ratio larger than the first flow rate ratio;
The film forming method according to claim 6 . The step (c) of modifying the silicon-containing film includes partially oxidizing the silicon-containing film.
The film forming method according to any one of claims 1 to 7. The step (d) of etching the silicon-containing film includes removing the modified silicon-containing film to form an opening of the recess.
The film forming method according to any one of claims 1 to 8. etching the silicon-containing film of (d) removes the silicon-containing film without using a plasma;
The film forming method according to any one of claims 1 to 9. The step of etching the silicon-containing film in (d) includes:
(d-1) supplying a fluorine-containing gas and a nitrogen-containing gas to the substrate to react with the modified silicon-containing film to form reaction by-products;
(d-2) removing the reaction by-products;
The film forming method according to any one of claims 1 to 10. The step (d-2) of removing reaction by-products includes sublimating and removing the reaction by-products by heat treatment.
The film forming method according to claim 11 . In the step (d-2) of removing reaction by-products, the temperature of the mounting table on which the substrate is mounted is controlled to 50° C. or higher.
The film forming method according to claim 11 or 12. (h) after (d), further etching the silicon-containing film on the upper portion and side wall of the recess;
The film forming method according to any one of claims 1 to 13. The step (h) of further etching the silicon-containing film comprises:
(h-1) supplying a fluorine-containing gas and a nitrogen-containing gas to the substrate to react with the modified silicon-containing film to form reaction by-products;
(h-2) removing the reaction by-products;
The film forming method according to claim 14. The step of forming the reaction by-product of (h-1) and the step of removing the reaction by-product of (h-2) are performed one or more times;
The film forming method according to claim 15. (g) after the step (d), the step of modifying the silicon-containing film formed in the recess with a plasma-activated nitrogen-containing gas;
The film forming method according to any one of claims 1 to 16. The silicon-containing film is a film containing silicon and nitrogen,
The film forming method according to any one of claims 1 to 17. The film containing silicon and nitrogen is any one of a SiN film, a SiCN film, a SiON film, and a SiOCN film,
19. The film forming method according to claim 18. The silicon-containing film is a Si film,
The film forming method according to any one of claims 1 to 17. The substrate has a plurality of recesses,
(e) further comprising determining whether the silicon-containing film has blocked the openings of the plurality of recesses;
In the step (c) of modifying the silicon-containing film, if it is determined in the step (e) that the silicon-containing film blocks the openings of all the recesses, the silicon-containing film is start reforming,
The film forming method according to any one of claims 1 to 20. (f) further comprising determining whether the silicon-containing film blocking the opening of the recess is oxidized;
The step (d) of etching the silicon-containing film starts etching the silicon-containing film when it is determined in the step (f) that the silicon-containing film blocking the opening of the recess is oxidized. ,
The film forming method according to any one of claims 1 to 21. The step (b) of forming the silicon-containing film and the step (c) of modifying the silicon-containing film are performed in the same processing apparatus.
The film forming method according to any one of claims 1 to 22. A film formation system having a plurality of processing apparatuses,
The plurality of processing devices,
a first processing apparatus configured to perform a step of activating a silicon-containing gas with plasma and supplying it to a substrate having recesses to form a silicon-containing film on the substrate;
a second processing apparatus configured to perform a step of partially modifying the silicon-containing film after the silicon-containing film closes the opening of the recess;
a third processing apparatus configured to selectively etch the modified silicon-containing film;
The first processing device and the second processing device are the same processing device or different processing devices,
The film forming system, wherein the first processing apparatus and the third processing apparatus, and the second processing apparatus and the third processing apparatus are separate processing apparatuses. A film formation system having a processing apparatus for processing a plurality of substrates,
The processing device is
a plurality of mounting tables for mounting the plurality of substrates;
a plurality of processing spaces corresponding to the mounting table;
with
The plurality of processing spaces are
a first processing space configured to perform a step of activating a silicon-containing gas with plasma and supplying it to a substrate having a recess to form a silicon-containing film on the substrate;
a second processing space configured to perform a step of partially modifying the silicon-containing film after the silicon-containing film closes the opening of the recess;
A third process configured to perform the step of supplying a fluorine-containing gas and a nitrogen-containing gas to the substrate and reacting with the modified silicon-containing film to form reaction by-products. space and
a fourth processing space configured to perform the step of removing the reaction by-product;
A deposition system.

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