WO2020262039A1

WO2020262039A1 - Substrate processing method and substrate processing system

Info

Publication number: WO2020262039A1
Application number: PCT/JP2020/023189
Authority: WO
Inventors: 聡一郎岡田; 志村　悟
Original assignee: 東京エレクトロン株式会社
Priority date: 2019-06-26
Filing date: 2020-06-12
Publication date: 2020-12-30

Abstract

Provided is a substrate processing method for processing a substrate, the method including: a step of supplying an application liquid on a layer to be processed of the substrate and forming an organic film containing carbon; a step of heat processing the substrate on which the organic film has been formed; a step of subjecting the organic film after heating processing to a predetermined process of cutting the bonds between carbons in the organic film, moving the carbons for which the bond has been cut within the organic film, and recombining the carbons with other carbons; and a step of supplying a resist liquid onto the organic film that has been subjected to the predetermined process to form a resist film.

Description

Substrate processing method and substrate processing system

This disclosure relates to a substrate processing method and a substrate processing system.

Patent Document 1 describes an organic film such as amorphous carbon (a-C) or SOC (spin-on carbon), a hard mask layer which is an inorganic film, and an organic film on a lower layer film such as a SiN film to be finally etched. It is disclosed that the antireflection film and the photoresist film of the above are formed in this order. Further, Patent Document 1 discloses that the aC film and the SOC film serve as a mask for etching the lower layer film to be the final etching target.

Japanese Unexamined Patent Publication No. 2012-204668

The technique according to the present disclosure increases the etching resistance of the organic film when the organic film which is the base film of the resist film and is used as the etching mask is formed by the coating process.

One aspect of the present disclosure is a substrate processing method for processing a substrate, in which a coating liquid is supplied onto a treatment target layer of the substrate to form a carbon-containing organic film, and the organic film is formed. In the step of heat-treating the substrate, the carbons contained in the organic film are cleaved, and the carbons whose bonds are cleaved are moved in the organic film and then recombined with other carbons. A step of performing a predetermined treatment on the organic film after the heat treatment and a step of supplying a resist solution onto the organic film on which the predetermined treatment has been performed to form a resist film. Including.

According to the present disclosure, when an organic film which is a base film of a resist film and is used as an etching mask is formed by a coating process, the etching resistance of the organic film can be increased.

It is a figure which shows typically the outline of the structure of the substrate processing system which concerns on 1st Embodiment. It is a top view which shows the outline of the structure of the 1st processing system of FIG. 1 schematically. It is a front view which shows the outline of the structure of the 1st processing system of FIG. 1 schematically. It is a back view schematically showing the outline of the structure of the first processing system of FIG. It is a figure which shows the SEM image of the cross section of the SOC film after the SOC film baking treatment and before the plasma treatment as a modification treatment is performed. It is a figure which shows the SEM image of the cross section of the SOC film after plasma treatment. It is a figure which shows the mass density of the SOC film before and after the plasma treatment. It is a figure which shows the indentation hardness of the SOC film before and after the plasma treatment. It is a figure which shows the etching rate of the SOC film before and after the plasma treatment. It is a figure which shows the component analysis result of the SOC film before and after the plasma treatment. It is a figure for demonstrating the reason why the SOC film became densified and the etching resistance was improved. It is a figure which shows the SEM image of the cross section of the SOC film after plasma treatment when the film thickness of the SOC film is large. It is a front view which shows the outline of the structure of the substrate processing system which concerns on 2nd Embodiment. It is a front view which shows the outline of the structure of the substrate processing system which concerns on 3rd Embodiment.

In the manufacturing process of semiconductor devices and the like, a resist coating process of applying a resist solution on a semiconductor wafer (hereinafter referred to as "wafer") to form a resist film, an exposure process of exposing the resist film, and an exposed resist film are applied. Development processing and the like for developing are sequentially performed, and a resist pattern is formed on the wafer. Then, after the resist pattern forming process, the process target layer is etched or the like using the resist pattern as a mask to form a predetermined pattern on the process target layer.

By the way, with the miniaturization of semiconductor devices and the like, etching with a high aspect ratio is required when etching the layer to be processed. As a technique for this purpose, a method of using an undercoat film formed under the resist film as a mask is known.
In Patent Document 1, an organic film such as an a-C film or an SOC film, a hard mask layer which is an inorganic film, an organic antireflection film, and a photoresist film are sequentially formed on the lower layer film to be finally etched. It is disclosed that an organic film such as an aC film or an SOC film is formed and used as an etching mask for the lower layer film to be finally etched.

In recent years, etching with a higher aspect ratio has been required and the amount of etching has increased. Therefore, an organic film as an etching mask for the final etching target is required to have high etching resistance. When an aC film formed by the CVD method is used as the organic film, the etching resistance of the organic film is high, but the throughput and embedding property are low. On the other hand, when a coating film such as a SoC film formed by the coating treatment is used as the organic film, the throughput and embedding property are higher than those of the aC film. However, the etching resistance of the current coating film such as the SoC film is not as high as that of the aC film.

Therefore, the technique according to the present disclosure increases the etching resistance of the organic film when the organic film which is the base film of the resist film and is used as the etching mask is formed by the coating treatment. As a result of diligent studies by the present inventors, it is found that the etching resistance of the organic film is improved by performing plasma treatment with plasma or heat treatment while irradiating an electron beam on the organic film formed by the coating treatment. I found out. In addition, as a result of further studies, the bonds between the carbons contained in the organic film are cleaved by plasma treatment or the like, and the carbons whose bonds are cleaved move in the organic film and recombine with other carbons. As a result, it was inferred that the etching resistance of the organic film was improved. The following embodiments are based on the above findings. In the present specification, the "etching resistance of the organic film" means the resistance at the time of etching using the organic film as an etching mask, and more specifically, a SiN film or the like using the organic film as an etching mask. Means the resistance to etching of the layer to be treated. The same applies to "etching resistance of SOC film" and "etching resistance of aC film".

Hereinafter, the substrate processing method and the substrate processing system according to this embodiment will be described with reference to the drawings. In the present specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

(First Embodiment)
FIG. 1 is a diagram schematically showing an outline of a configuration of a substrate processing system according to a first embodiment.

As shown in the figure, the substrate processing system 1 has three

processing systems

10, 20, and 30 that perform desired processing on the wafer W as a substrate. Further, the substrate processing system 1 is provided with a control unit 40. The control unit 40 is, for example, a computer equipped with a CPU, a memory, or the like, and has a program storage unit (not shown). The program storage unit stores programs that control various processes in the substrate processing system 1. The program may be recorded on a computer-readable storage medium and may be installed on the control unit 40 from the storage medium. Part or all of the program may be realized by dedicated hardware (circuit board).

In the first processing system 10, photolithography processing or the like is performed on the wafer W.
FIG. 2 is a plan view schematically showing an outline of the configuration of the first processing system 10. 3 and 4 are a front view and a rear view, respectively, schematically showing an outline of the internal configuration of the first processing system 10.

As shown in FIG. 2, the first processing system 10 includes a cassette station 100 into which a cassette C accommodating a plurality of wafers W is carried in and out, and a plurality of processing devices for performing predetermined processing on the wafer W. It has a processing station 101 and a wafer. The first processing system 10 has a configuration in which the cassette station 100, the processing station 101, and the interface station 103 that transfers the wafer W between the exposure apparatus 102 adjacent to the processing station 101 are integrally connected. Have.

The cassette station 100 is provided with a cassette mounting stand 110. The cassette mounting table 110 is provided with a plurality of cassette mounting plates 111 on which the cassette C is mounted when the cassette C is carried in and out of the substrate processing system 1.

The cassette station 100 is provided with a wafer transfer device 113 that is movable on a transfer path 112 extending in the X direction. The wafer transfer device 113 is also movable in the vertical direction and around the vertical axis (θ direction), and is a transfer device for the cassette C on each cassette mounting plate 111 and the third block G3 of the processing station 101 described later. Wafer W can be conveyed between them.

The processing station 101 is provided with a plurality of, for example, four blocks equipped with various devices, that is, first blocks G1 to fourth blocks G4. For example, a first block G1 is provided on the front side of the processing station 101 (negative direction in the X direction in FIG. 2), and on the back side of the processing station 101 (positive direction in the X direction in FIG. 2, upper side in the drawing). Is provided with a second block G2. Further, the third block G3 described above is provided on the cassette station 100 side (negative direction side in the Y direction of FIG. 2) of the processing station 101, and the interface station 103 side of the processing station 101 (positive in the Y direction of FIG. 2). A fourth block G4 is provided on the directional side).

As shown in FIG. 3, a plurality of liquid processing devices, for example, a developing processing device 120, an organic film forming device 121, an inorganic film forming device 122, and a resist coating device 123 are arranged in this order from the bottom in the first block G1. There is.

The developing processing apparatus 120 develops the wafer W. Specifically, the developing processing apparatus 120 supplies a developing solution onto the resist film of the wafer W to form a resist pattern.

The organic film forming apparatus 121 forms a carbon-containing organic film which is a film used as a mask for transferring a pattern to the processing target layer of the wafer W and is a base film of a resist film. Specifically, the organic film forming apparatus 121 applies an organic film material as a material for forming the organic film to the layer to be processed of the wafer W to form the organic film. In this example, the organic film is an SOC film, and the organic film material is an SOC material. The layer to be treated is, for example, a SiN film.

The inorganic film forming apparatus 122 forms an inorganic film on the organic film of the wafer W after the reforming treatment by the reforming apparatus described later. Specifically, the inorganic film forming apparatus 122 coats the organic film with an inorganic film material as a material for forming the inorganic film to form the inorganic film. In this example, the inorganic film is an SOG (spin-on-glass) film, and the inorganic film material is an SOG material. The inorganic film is not limited to SOG, and may be another Si-containing inorganic film such as a film used as a Si-containing antireflection film (SiARC).

The resist coating device 123 applies a resist solution to the wafer W to form a resist film. Specifically, the resist coating apparatus 123 is placed on the organic film of the wafer W after the modification treatment by the reforming apparatus described later, and more specifically, on the inorganic film formed on the organic film. A resist solution is applied to form a resist film.

For example, the developing processing apparatus 120, the organic film forming apparatus 121, the inorganic film forming apparatus 122, and the resist coating apparatus 123 are arranged side by side in the horizontal direction. The number and arrangement of the developing processing apparatus 120, the organic film forming apparatus 121, the inorganic film forming apparatus 122, and the resist coating apparatus 123 can be arbitrarily selected.

In the organic film forming apparatus 121, the inorganic film forming apparatus 122, and the resist coating apparatus 123, film formation is performed by a spin coating method, that is, spin coating. In the spin coating method, for example, a predetermined processing liquid is discharged onto the wafer W from the coating nozzle, and the wafer W is rotated to diffuse the processing liquid on the surface of the wafer W.

As shown in FIG. 4, the second block G2 is provided with heat treatment devices 130 for performing heat treatment such as heating and cooling of the wafer W side by side in the vertical direction and the horizontal direction. The number and arrangement of these heat treatment devices 130 can be arbitrarily selected. Further, known devices can be used for the heat treatment device 130.

A plurality of

delivery devices

140, 141, 142, 143, 144, 145, 146 are provided in the third block G3 in order from the bottom. Further, in the fourth block G4, a plurality of

delivery devices

150, 151, and 152 are provided in order from the bottom.

As shown in FIG. 2, a wafer transfer region D is formed in a region surrounded by the first block G1 to the fourth block G4. In the wafer transfer region D, for example, a plurality of wafer transfer devices 160 having transfer arms 160a that can move in the Y direction, the X direction, the θ direction, and the vertical direction are arranged. The wafer transfer device 160 moves in the wafer transfer area D and transfers the wafer W to desired devices in the surrounding first block G1, second block G2, third block G3, and fourth block G4. it can.

Further, as shown in FIG. 4, the wafer transfer region D is provided with a shuttle transfer device 170 that linearly conveys the wafer W between the third block G3 and the fourth block G4.

The shuttle transport device 170 is linearly movable in the Y direction of FIG. 4, for example. The shuttle transfer device 170 moves in the Y direction while supporting the wafer W, and can transfer the wafer W between the transfer device 142 of the third block G3 and the transfer device 152 of the fourth block G4.

As shown in FIG. 2, a wafer transfer device 180 is provided next to the third block G3 on the positive direction side in the X direction. The wafer transfer device 180 has, for example, a transfer arm 180a that can move in the X direction, the θ direction, and the vertical direction. The wafer transfer device 180 can move up and down while supporting the wafer W to transfer the wafer W to each transfer device in the third block G3.

The interface station 103 is provided with a wafer transfer device 190 and a transfer device 191. The wafer transfer device 190 has, for example, a transfer arm 190a that can move in the Y direction, the θ direction, and the vertical direction. The wafer transfer device 190 can, for example, support the wafer W on the transfer arm 190a and transfer the wafer W between each transfer device, the transfer device 191 and the exposure device 102 in the fourth block G4.

Returning to the description of FIG.
In the second processing system 20, plasma treatment of the wafer W by plasma, specifically, etching treatment of the wafer W by plasma and the like is performed.
The second processing system 20 has an etching apparatus 201 and a reforming apparatus 202. Although not shown, the second processing system 20 is provided with a cassette station for loading and unloading the cassette C and a wafer transfer device for transporting the wafer W.

The etching apparatus 201 etches a desired film on the wafer W with plasma, and is composed of, for example, a RIE (Reactive Ion Etching) apparatus.

The reformer 202 cuts the bonds between carbons contained in the organic film (SOC film in this example) on the wafer W, and after the carbons at which the bonds have been broken are moved in the organic film, other carbons are used. Plasma treatment with plasma is performed as a predetermined treatment (hereinafter, may be referred to as "modification treatment") for recombination with.
The reforming treatment by the reforming apparatus 202 increases the mass density of the organic film. Specifically, the modification treatment densifies the portion of the organic film on the film surface side and increases the mass density of the portion.

A known etching apparatus can be used for the etching apparatus 201. Further, as the physical structure of the reforming apparatus 202, a structure similar to that of a known apparatus for performing plasma treatment with plasma can be used.

In the third processing system 30, the wafer W is subjected to a base film peeling process or the like.
The third processing system 30 has a peeling device 301.
The peeling device 301 peels the layer used as a mask at the time of etching from the wafer W to which the etching process of the layer to be processed has been performed. Specifically, for example, the organic film used as a mask when etching the film to be treated is removed by a lift-off treatment using a predetermined removing solution.
The third processing system 30 is also provided with a cassette station for loading and unloading the cassette C and a wafer transfer device for transporting the wafer W.

Next, an example of substrate processing performed by the substrate processing system 1 configured as described above will be described. In the following example, a SiN film as a layer to be processed is formed in advance on the wafer W.

(SOC film formation treatment)
First, in the organic film forming apparatus 121 of the first processing system 10, the SOC material as a coating liquid is applied onto the processing target layer of the wafer W to form an SOC film. The thickness of the SOC film formed by the organic film forming apparatus 121 is, for example, 50 to 3000 nm.

(SOC film baking treatment)
Next, in the heat treatment apparatus 130, the wafer W on which the SOC film is formed is heat-treated, that is, the SOC film is baked. The temperature of the wafer W during the baking process of the SOC film is, for example, 250 ° C. to 750 ° C.

(Modification process)
Subsequently, the cassette C containing the wafer W after the baking treatment of the SOC film is conveyed to the second processing system 20, and the reformer 202 performs plasma treatment with plasma as the reforming treatment on the wafer W. Is done. This plasma treatment is performed on the entire surface of the wafer. During plasma processing, the processing chamber (not shown) within the housing the wafers W of the reformer 202, for example, is introduced H ₂ gas and Ar gas, an atmosphere of a mixed gas of H ₂ gas and Ar gas Below the plasma is generated. Further, in addition to the H ₂ gas and the Ar gas, a carbon-containing gas such as CF ₄ gas or CH ₄ gas may be introduced. Instead of one or both of H ₂ gas and Ar gas, CF ₄ gas, NF ₃ gas, CHF ₃ gas, CO ₂ gas, CH ₂ F ₂ gas, CH ₄ gas and C ₄ F ₈ gas At least one of them may be introduced.
According to the results of diligent studies by the present inventors, as will be described in detail later, the plasma treatment as the modification treatment breaks the bonds between carbons (for example, cross-linking bonds) contained in the SOC film. Further, by this plasma treatment, the polymer containing carbon whose bond is broken moves in the SOC membrane, and then rebonds to the carbon whose bond is broken. As a result, the mass density of the SOC film is increased, and the etching resistance of the SOC film is improved. Specifically, the plasma treatment densifies the portion of the SOC film on the film surface side, increases the mass density of the portion, and improves the etching resistance of the portion.

(SOG film formation treatment)
Next, the cassette C containing the wafer W after the plasma treatment in the reforming apparatus 202 is conveyed to the first processing system 10, and the SOG material is placed on the SOC film of the wafer W in the inorganic film forming apparatus 122. Is applied to form an SOG film. Next, in the heat treatment apparatus 130, the wafer W on which the SOG film is formed is heat-treated, that is, the SOG film is baked. The thickness of the SOG film formed by the inorganic film forming apparatus 122 is 10 to 100 nm.

(Resist film forming treatment)
Subsequently, in the resist coating apparatus 123, the resist liquid is applied onto the SOG film of the wafer W to form the resist film. As the resist solution, for example, ArF resist solution is used. Next, in the heat treatment apparatus 130, the wafer W on which the resist film is formed is heat-treated, that is, the resist film is subjected to PAB treatment. The thickness of the resist film formed by the resist coating device 123 is 20 to 100 nm.

(Exposure processing)
Next, in the exposure apparatus 102, an exposure process is performed on the wafer W, and the resist film is exposed to a predetermined pattern. After the exposure, the heat treatment apparatus 130 heat-treats the exposed wafer W, that is, the resist film is subjected to the PEB treatment.

(Development processing)
After the PEB treatment, the developing solution is supplied onto the resist film of the wafer W in the developing processing apparatus 120, and the resist film is developed. As a result, a resist pattern is formed on the SOG film of the wafer W.

(SOG film etching)
Next, the cassette C containing the developed wafer W is conveyed to the second processing system 20, and the etching apparatus 201 performs an etching process of the SOG film using the resist pattern as a mask on the wafer W. .. As a result, an SOG pattern is formed on the SOC film.

(SOC film etching)
Next, in the etching apparatus 201, the etching process of the SOC film using the SOG pattern as a mask is performed. As a result, an SOC pattern is formed on the layer to be processed.

(Etching of layer to be processed)
Subsequently, the etching apparatus 201 performs an etching process of the layer to be processed using the SOC pattern as a mask. As a result, a pattern of the layer to be processed is formed. The SOG pattern may be removed before etching the layer to be processed. The removal of the SOG pattern can be performed, for example, by an etching process in the etching apparatus 201.
An etching apparatus 201 different from the above-mentioned SOG film etching, SOC film etching, and processing target layer etching may be used.

(Peeling process)
After that, the cassette C containing the wafer W after etching the layer to be processed is conveyed to the third processing system 30, and the stripping device 301 performs the stripping process of the SOC pattern on the wafer W. Specifically, Lift-off processing is performed. In the lift-off process, a predetermined removal liquid is supplied onto the wafer W, and the removal liquid dissolves the non-dense portion of the SOC pattern on the processing target layer side. Since the portion of the SOC pattern on the treatment target layer side (that is, the portion at the base of the SOC pattern) is dissolved, the portion on the film surface side that is densified in the SOC pattern and is not dissolved in the removal liquid (that is, the upper portion of the SOC pattern) is also removed. To. As a result, the entire SOC pattern is peeled off. The removal liquid used in the lift-off treatment is, for example, nitric acid, hydrofluoric acid, hydrochloric acid, a mixed solution of sulfuric acid and hydrogen peroxide, a mixed solution of ammonia and hydrogen peroxide, an organic solvent and the like. If the SOG pattern remains on the SOC pattern during this lift-off process, the SOG pattern is also removed together with the SOC pattern.
Further, when not only the portion of the SOC pattern on the film surface side but the entire SOC pattern is densified, the peeling process is the same as the conventional process for peeling the aC film formed by the CVD method. Processing is done.

After the peeling process, the wafer W is returned to the cassette C, whereby the substrate process in the substrate processing system 1 is completed.

As described above, the substrate processing method according to the present embodiment includes a step of supplying an organic film material on the layer to be processed of the wafer W to form a carbon-containing organic film, and a wafer W on which the organic film is formed. A step of performing a heat treatment and a modification treatment in which the bond between carbons contained in the organic film is cleaved and the carbon having the broken bond is moved in the organic film and then rebonded with other carbons. The process includes a step of performing the plasma treatment as described on the organic film after the heat treatment, and a step of supplying a resist liquid onto the organic film subjected to the plasma treatment to form a resist film. That is, in the substrate treatment method according to the present embodiment, the organic film which is the base film of the resist film and is used as the etching mask and is formed by the coating treatment is subjected to the above-mentioned modification treatment before the resist film is formed. Perform plasma processing. This method is based on the results of diligent studies by the present inventors.

The present inventors have repeated various experiments in order to improve the etching resistance of the organic film formed by the coating treatment, which is the base film of the resist film. As a result, even if the organic film is baked, the etching resistance of the organic film does not increase to the etching resistance of the aC film, but by performing the plasma treatment on the organic film, the organic film is formed. It was found that the etching resistance was improved to the level of the aC film.

FIG. 5 is a diagram showing an SEM image of a cross section of the SOC film after the SOC film baking treatment and before the plasma treatment as the reforming treatment is performed, and FIG. 6 is a diagram showing a cross section of the SOC film after the plasma treatment. It is a figure which shows the SEM image of. FIG. 7 is a diagram showing the mass density of the SOC film before and after the plasma treatment, FIG. 8 is a diagram showing the indentation hardness of the SOC film before and after the plasma treatment, and FIG. 9 is a diagram showing the etching rate of the SOC film before and after the plasma treatment. is there. For comparison, FIGS. 7 to 9 also show the mass density, indentation hardness, and etching rate of the aC film formed by the CVD method. FIG. 10 is a diagram showing the component analysis results of the SOC film before and after the plasma treatment.
In the plasma treatment when the results of FIGS. 6 to 9 were obtained, plasma was generated in the treatment chamber in which CF ₄ gas, NF ₃ gas, and H ₂ gas were introduced at flow rates of 10 sccm, 10 sccm, and 180 sccm, respectively. The inductively coupled power and the bias power were 2000 W, respectively. Further, in the etching when the result of FIG. 9 was obtained, the processing conditions were the same as those in the etching of the SiN film. Specifically, plasma was generated in the processing chamber in which CH ₂ F ₂ gas, O ₂ gas, and Ar gas were introduced at flow rates of 20 sccm, 30 sccm, and 300 sccm, respectively, and the inductively coupled power and the bias power were 300 W, respectively. ..

As shown in FIG. 5, the SOC film F1 after the SOC film baking treatment and before the plasma treatment is composed of grains having a large particle size, and large voids are present between the grains.
On the other hand, as shown in FIG. 6, the SOC film F2 after the plasma treatment has a reduced film thickness (for example, the film thickness which was about 250 nm before the plasma treatment becomes about 100 nm), but the particles have a small particle size. It is composed of no large voids between grains. That is, the SOC film F2 after the plasma treatment is denser than the SOC film F2 before the plasma treatment.
Actually, as shown in FIG. 7, the mass density of the SOC film F2 after the plasma treatment is higher than that of the SOC film F1 before the plasma treatment, and further higher than that of the aC film.
Further, as shown in FIG. 8, the indentation hardness of the SOC film F2 after the plasma treatment is higher than that of the SOC film F1 before the plasma treatment, which is equivalent to that of the aC film.

Further, as shown in FIG. 9, the etching rate of the SOC film F2 after the plasma treatment is less than half that of the SOC film F2 before the plasma treatment, as compared with the etching under the processing conditions for etching the SiN film. , AC film is equivalent. That is, the SOC film F2 after the plasma treatment has high resistance to etching of the treatment target layer when the treatment target layer is a SIN film, and is equivalent to the aC film.
Although not shown, the etching rate of the SOC film F2 after the plasma treatment is lower than that of the SOC film F2 before the plasma treatment even when the etching is performed under the treatment conditions for etching the silicon oxide film. -It is equivalent to C film. That is, the SOC film F2 after the plasma treatment has improved resistance to etching of the treatment target layer even when the treatment target layer is an oxide film such as a silicon oxide film.

Further, as shown in FIG. 10, there is almost no change in the components of the SOC film before and after the plasma treatment. Based on this point, the reason why the SOC film is densified as described above and its etching resistance is improved to the same level as that of the aC film can be inferred as follows.

FIG. 11 is a schematic view for explaining the reason why the SOC film is densified and the etching resistance is improved.
As shown in FIG. 11A, a plurality of polymers P are entangled in the particles having a large particle size that constitute the SOC film after the baking treatment and before the reforming treatment. As shown in FIG. 11B, when energy E is applied to the entangled polymer P by plasma or the like, the bonds between the carbon atoms P1 constituting the polymer P are broken. In addition, the polymer containing carbon atoms whose bonds have been broken moves in the SOC film due to the energy generated by the collision of molecules with a large molecular weight (for example, Ar gas molecules) with the surface of the SOC film during plasma treatment. After that, the carbon atoms whose bonds have been broken are rebonded to each other. Unlike this, even if the polymer containing carbon atoms with broken bonds does not flow in the SOC film and the carbon atoms with broken bonds rebond to each other on the spot, the density of the SOC film does not change. Does not occur. On the other hand, as described above, the carbon atom whose bond has been broken moves in the SOC film and then recombines, so that the carbon atom P1 has a diamond shape in the SOC film as shown in FIG. 11 (C). They are arranged so as to form a structure having three-dimensional regularity (hereinafter, may be abbreviated as "three-dimensional structure") such as a structure. An SOC film in which carbon atoms are arranged so as to form a three-dimensional structure such as a diamond-type structure is formed into an SOC film in which carbon atoms are arranged so as to form a structure having a planar regularity such as a graphite-type structure. In comparison, the mass density is higher. That is, the SOC film is densified by the above recombination. As a result, it is considered that the etching resistance is improved.
The above points are the same not only for the SOC film but also for other carbon-containing organic films formed by the coating treatment.

Therefore, in the present embodiment, as described above, with respect to the organic film which is the base film of the resist film and is formed by the coating treatment, the bonds between the carbons contained in the organic film are cut before the resist film is formed. A modification process is performed in which the carbon whose bond is broken is moved in the organic film and then rebonded with other carbon. Then, in the present embodiment, plasma treatment is performed as the reforming treatment. Therefore, according to the present embodiment, when an organic film which is a base film of a resist film and is used as an etching mask is formed by a coating treatment, the etching resistance of the organic film can be increased.

Further, in the present embodiment, plasma treatment as a modification treatment is performed on the entire organic film before forming the resist film. In other words, in the present embodiment, the entire organic film is subjected to plasma treatment as a modification treatment before forming the pattern of the organic film. Unlike the present embodiment, when plasma treatment is performed after forming the pattern of the organic film, the shape of the pattern is impaired as the pattern of the organic film becomes densified, and the pattern of the organic film is used as an etching mask. It may not be possible to properly etch the layer to be treated. On the other hand, in the present embodiment, since the entire organic film is subjected to plasma treatment before forming the pattern of the organic film, the shape of the pattern of the organic film is not affected by the plasma treatment, so that the pattern of the organic film is not affected. Can be appropriately etched for the layer to be processed using the above as an etching mask.
When plasma treatment as a reforming treatment is performed after forming a resist pattern on the organic film, the remaining state of the resist pattern differs depending on the position of the wafer W, so that the time during which plasma is irradiated depends on the position of the wafer W. Therefore, the degree of SOC modification differs depending on the position of the wafer W.

Further, according to the test conducted by the present inventors, when the SOC film is subjected to plasma treatment as a modification treatment, not only the etching rate of the SOC film with respect to the etching of the film to be treated but also the etching of the SOC film itself. The etching rate of the SOC film also decreases. Even if the etching rate of the SOC film with respect to the etching of the SOC film itself decreases in this way, the SOG can have a high selectivity between the SOC film and the etching as a mask in the etching, as in the present embodiment. An inorganic membrane such as a membrane may be used. Thereby, the etching of the SOC film itself can be appropriately performed. Even if an inorganic film such as an SOG film is not used, the SOC film itself can be appropriately etched by increasing the thickness of the mask in the etching of the SOC film itself.
The above points are the same not only for the SOC film but also for other carbon-containing organic films formed by the coating treatment.

Further, in the present embodiment, since plasma treatment is performed as a modification treatment of the SOC film using plasma generated in an atmosphere of an inert gas such as Ar gas, the SOC film is formed by the plasma of the inert gas. Since it is struck, the SOC film can be densified.

As described above, even if a carbon-containing gas such as CF ₄ gas, CH ₄ gas, CHF ₃ gas, or CO ₂ gas is introduced into the processing container (not shown) of the reformer 202 during plasma treatment. Good. According to the findings of the present inventors, by using the plasma formed by introducing the carbon-containing gas, it is possible to suppress the decrease in the film thickness of the SOC film during the plasma treatment. Further, by plasma treatment using this plasma, carbon (C) is added or replenished into the SOC film, so that the SOC film can be further densified.

FIG. 12 is a diagram showing an SEM image of a cross section of the SOC film after plasma treatment when the film thickness of the SOC film is large.
In the example of FIG. 6, the entire SOC film was densified after the plasma treatment, but when the thickness of the SOC film is large, as shown in FIG. 12, the film surface side of the SOC film F2 after the plasma treatment Only the part F21 of is densified. This is because when the film thickness of the SOC film is large, the plasma does not reach the deep part of the SOC film.
Even when the SOC film is thin, only the film surface portion of the SOC film can be densified by reducing the execution time of the plasma treatment.
By densifying only the film surface portion of the SOC film, the SOC film can be removed by the lift-off treatment. The removal process of the SOC film when the entire SOC film is densified is the same process as the conventional process for peeling the a-C film formed by the CVD method, and the a-C film is peeled off. The lift-off process can be performed easily and in a short time as compared with the conventional process for the purpose.

Further, according to the present embodiment, the depth from the film surface of the portion to be densified in the SOC film can be controlled by changing the execution time of the plasma treatment.

(Second Embodiment)
FIG. 13 is a front view showing an outline of the configuration of the substrate processing system according to the second embodiment.
In the first embodiment, the second processing system 20 that performs etching with plasma or the like is provided with a reforming device 202 that performs plasma treatment as a reforming treatment. On the other hand, in the present embodiment, as shown in FIG. 13, the substrate processing system 50 in which the resist film forming treatment and the like are performed is provided with the reforming device 131 that performs plasma treatment as the reforming treatment. Throughput can be improved by providing the reformer 131 in the substrate processing system 50 in which the resist film forming process or the like is performed.

(Third Embodiment)
FIG. 14 is a front view showing an outline of the configuration of the substrate processing system according to the third embodiment.
In the first embodiment and the second embodiment, plasma treatment is performed as a modification treatment for the organic film. The reforming treatment is not limited to this. For example, the reformer 132 of the substrate processing system 60 according to the present embodiment of FIG. 14 heats the wafer W while irradiating the organic film of the wafer W with an electron beam as a reforming process for the organic film. ..

By irradiation with an electron beam, the bonds between carbons contained in the organic film are broken. Due to the heat applied to the wafer W, the polymer containing carbon whose bonds have been broken flows in the organic film, and the carbons whose bonds have been broken are rebonded to each other. As a result, the carbon atoms are arranged in the organic film so as to form a three-dimensional structure including a diamond-shaped structure. Therefore, as a modification treatment for the organic film, the organic film of the wafer W is heated while irradiating the organic film with an electron beam, so that the organic film can be densified and the etching resistance can be improved. Actually, the present inventors have confirmed that by performing the modification treatment according to the present embodiment, the SOC film as an organic film becomes denser and the indentation hardness becomes higher than that before the treatment, and the etching resistance is improved. We have confirmed that it can be improved.

Since the electron beam reaches a portion far from the film surface of the organic film, the modification treatment according to this embodiment is useful, for example, when it is necessary to densify the entire organic film having a large film thickness.

The processing conditions for the reforming treatment according to this embodiment are as follows, for example.
Electron beam acceleration voltage: 1kV-70kV
Oxygen concentration in the processing chamber of the reforming treatment equipment: ~ 100ppm
Wafer W temperature: 250 ° C to 500 ° C

In order to achieve the above-mentioned low oxygen concentration of ~ 100 ppm, the processing chamber of the reformer 125 may be an atmosphere of an inert gas such as nitrogen gas.

In the present embodiment, the substrate processing system 60 in which the resist film is formed and the like is provided with a reforming device 132 that heats the wafer W while irradiating the organic film of the wafer W with an electron beam. Instead of this, a reformer that performs the same treatment may be provided outside the processing system in which the resist film forming treatment or the like is performed.

In the above description, the organic film is baked after the formation of the organic film and before the modification treatment. However, the baking treatment involves an unnecessary solvent in the organic film and an unnecessary low molecular weight polymer. This is a process for stabilizing the organic film by removing the solvent, and may be omitted.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The above-described embodiment may be omitted, replaced, or changed in various forms without departing from the scope of the appended claims and the gist thereof.

The following configurations also belong to the technical scope of the present disclosure.
(1) A substrate processing method for processing a substrate.
A step of supplying a coating liquid onto the layer to be treated of the substrate to form a carbon-containing organic film, and
The step of heat-treating the substrate on which the organic film is formed and
After the heat treatment, a predetermined treatment of cleaving the bonds between the carbons contained in the organic film and moving the carbon having the broken bonds in the organic film and then rebonding the carbons with other carbons is performed. And the process to be performed on the organic film
A substrate processing method comprising a step of supplying a resist liquid onto the organic film that has been subjected to the predetermined treatment to form a resist film.
According to the above (1), when an organic film which is a base film of a resist film and is used as an etching mask is formed by a coating process, the organic film is subjected to the predetermined treatment, so that the organic film is etched. The resistance can be increased.

(2) An inorganic film is formed on the organic film after the predetermined treatment after the step of performing the predetermined treatment on the organic film after the heat treatment and before the step of forming the resist film. The substrate processing method according to (1) above, which comprises a step of forming.

(3) The substrate processing method according to (1) or (2) above, which comprises a step of supplying a developing solution onto the resist film to form a resist pattern.

(4) The substrate processing method according to any one of (1) to (3) above, wherein the predetermined process is a plasma process using plasma.

(5) The substrate processing method according to (4) above, wherein the plasma is generated in an atmosphere containing an inert gas.

(6) The substrate processing method according to (4) or (5) above, wherein the plasma is generated in an atmosphere containing a carbon-containing gas.

(7) The substrate processing method according to any one of (1) to (3) above, wherein the predetermined process is a process of heating the substrate while irradiating the substrate with an electron beam.

(8) A substrate processing system that processes a substrate.
An organic film forming apparatus for forming an organic film by supplying a coating liquid containing carbon onto the layer to be treated of the substrate.
A heating device that heats the substrate on which the organic film is formed, and
After the heat treatment, a predetermined treatment of cleaving the bond between carbons contained in the organic film and moving the carbon having the cleaved bond in the organic film and then recombination with another carbon is performed. The reformer performed on the organic film of
A substrate processing system including a resist coating apparatus that supplies a resist liquid onto the organic film that has been subjected to the predetermined treatment to form a resist film.

1, 50, 60 Substrate processing system 121 Organic film forming device 123 Resist

coating device

125, 131, 132, 202 Modification device 130 Heat treatment device W wafer

Claims

It is a substrate processing method that processes a substrate.
A step of supplying a coating liquid onto the layer to be treated of the substrate to form a carbon-containing organic film, and
The step of heat-treating the substrate on which the organic film is formed and
After the heat treatment, a predetermined treatment of cleaving the bonds between the carbons contained in the organic film and moving the carbon having the broken bonds in the organic film and then rebonding the carbons with other carbons is performed. And the process to be performed on the organic film
A substrate processing method comprising a step of supplying a resist liquid onto the organic film that has been subjected to the predetermined treatment to form a resist film.
A step of forming an inorganic film on the organic film after the predetermined treatment after the step of performing the predetermined treatment on the organic film after the heat treatment and before the step of forming the resist film. The substrate processing method according to claim 1, which comprises.
The substrate processing method according to claim 1 or 2, which comprises a step of supplying a developing solution onto the resist film to form a resist pattern.
The substrate treatment method according to any one of claims 1 to 3, wherein the predetermined treatment is plasma treatment using plasma.
The substrate processing method according to claim 4, wherein the plasma is generated in an atmosphere containing an inert gas.
The substrate processing method according to claim 4 or 5, wherein the plasma is generated in an atmosphere containing a carbon-containing gas.
The substrate processing method according to any one of claims 1 to 3, wherein the predetermined process is a process of heating the substrate while irradiating the substrate with an electron beam.
A substrate processing system that processes substrates
An organic film forming apparatus for forming an organic film by supplying a coating liquid containing carbon onto the layer to be treated of the substrate.
A heating device that heats the substrate on which the organic film is formed, and
After the heat treatment, a predetermined treatment of cleaving the bond between carbons contained in the organic film and moving the carbon having the cleaved bond in the organic film and then recombination with another carbon is performed. The reformer performed on the organic film of
A substrate processing system including a resist coating apparatus that supplies a resist liquid onto the organic film that has been subjected to the predetermined treatment to form a resist film.