WO2021044882A1

WO2021044882A1 - Film formation method

Info

Publication number: WO2021044882A1
Application number: PCT/JP2020/031752
Authority: WO
Inventors: 健次大内; 秀司東雲; 河野　有美子; 進一池
Original assignee: 東京エレクトロン株式会社
Priority date: 2019-09-05
Filing date: 2020-08-24
Publication date: 2021-03-11

Abstract

This film formation method for selectively forming a film on a substrate comprises a preparation step, a first film formation step, a second film formation step and a first removal step. In the preparation step, a substrate having a surface to which a first film and a second film are exposed is prepared. In the first film formation step, a self-assembled monolayer film is formed on the first film by supplying a compound for forming a self-assembled monolayer film that suppresses the formation of a third film, said compound having a functional group containing a fluorine atom and a carbon atom, onto the substrate. In the second film formation step, a third film is formed on the second film. In the first removal step, the third film formed in the vicinity of the self-assembled monolayer film is removed by irradiating the surface of the substrate with at least either ions or active species. Meanwhile, the third film is more likely to form a volatile compound than the first film by being combined with fluorine atoms and carbon atoms contained in the self-assembled monolayer film.

Description

Film formation method

Various aspects and embodiments of the present disclosure relate to film formation methods.

In the manufacture of semiconductor devices, photography technology is widely used as a technology for selectively forming a film on a specific region on the surface of a substrate. For example, after forming the lower layer wiring, an insulating film is formed, a dual damascene structure having trenches and via holes is formed by photolithography and etching, and a conductive film such as Cu is embedded in the trenches and via holes to form wiring.

However, in recent years, the miniaturization of semiconductor devices has been progressing more and more, and there are cases where the alignment accuracy is not sufficient with the photolithography technology.

Therefore, there is a demand for a method of selectively forming a film on a specific region on the surface of a substrate without using photolithography technology. As such a method, a technique for forming a self-assembled monolayer (SAM) in a region on the surface of a substrate for which film formation is not desired has been proposed (for example, Patent Documents 1 to 4 and non-patents). References 1 to 4). Since the predetermined film is not formed in the surface region of the substrate on which the SAM is formed, the predetermined film can be formed only in the surface region of the substrate on which the SAM is not formed.

Special Table 2007-501902 Special Table 2007-533156 Special Table 2010-540773 Japanese Patent Application Laid-Open No. 2013-520028

The present disclosure provides a film forming method capable of improving the productivity of a semiconductor device using selective film forming.

One aspect of the present disclosure is a film forming method for selectively forming a film on a substrate, which comprises a preparation step, a first film forming step, a second film forming step, and a first removing step. Including. In the preparatory step, a substrate in which the first film and the second film are exposed on the surface is prepared. In the first film forming step, a compound for forming a self-assembled monolayer having a functional group containing fluorine and carbon and suppressing the formation of the third film is supplied onto the substrate. , A self-assembled monolayer is formed on the first film. In the second film forming step, a third film is formed on the second film. In the first removal step, the surface of the substrate is irradiated with at least one of ions and active species to remove the third film formed in the vicinity of the self-assembled monolayer. Further, the third membrane is a membrane that is easier to form a volatile compound by combining with fluorine and carbon contained in the self-assembled monolayer than the first membrane.

According to various aspects and embodiments of the present disclosure, the productivity of semiconductor devices using selective film formation can be improved.

FIG. 1 is a schematic view showing an example of a film forming system according to an embodiment of the present disclosure. FIG. 2 is a flowchart showing an example of the film forming method according to the first embodiment. FIG. 3 is a cross-sectional view showing an example of a substrate prepared in the preparation step of the first embodiment. FIG. 4 is a cross-sectional view showing an example of a substrate after SAM is formed on the first film in the first embodiment. FIG. 5 is a cross-sectional view showing an example of a substrate after the third film is formed on the second film in the first embodiment. FIG. 6 is a schematic cross-sectional view showing an example of a plasma processing apparatus used in the first removal step. FIG. 7 is a cross-sectional view showing an example of the substrate after the nuclei of the third film on the SAM have been removed in the first embodiment. FIG. 8 is a cross-sectional view showing an example of the substrate after the SAM on the first film has been removed in the first embodiment. FIG. 9 is a flowchart showing an example of the film forming method in the second embodiment. FIG. 10 is a cross-sectional view showing an example of a substrate prepared in the preparation step of the second embodiment. FIG. 11 is a cross-sectional view showing an example of the substrate after the SAM is formed on the metal wiring in the second embodiment. FIG. 12 is a cross-sectional view showing an example of the substrate after the dielectric film is formed in the second embodiment. FIG. 13 is a cross-sectional view showing an example of the substrate after the SAM has been removed in the second embodiment. FIG. 14 is a cross-sectional view showing an example of the substrate after the SAM is further formed on the metal wiring in the second embodiment. FIG. 15 is a cross-sectional view showing an example of a substrate after the dielectric film is further formed on the dielectric film in the second embodiment. FIG. 16 is a cross-sectional view showing an example of the substrate after the SAM has been removed in the second embodiment. FIG. 17 is a flowchart showing another example of the film forming method in the second embodiment. FIG. 18 is a flowchart showing still another example of the film forming method in the second embodiment.

Hereinafter, embodiments of the disclosed film forming method will be described in detail with reference to the drawings. The disclosed film forming method is not limited by the following embodiments.

By the way, in the conventional selective film formation, a substrate having an exposed metal film and an insulating film on the surface is prepared, and a SAM that suppresses the film formation of the oxide film is formed on the metal film. Then, an oxide film is formed on the insulating film. At this time, since the film formation of the oxide film on the metal film is suppressed by SAM, the oxide film is not formed on the metal film.

However, since the ability of SAM to suppress the formation of an oxide film is not perfect, the nucleus of the oxide film may grow on the SAM as well. As a result, if the film formation of the oxide film is continued, the oxide film is also formed on the SAM. Therefore, it is necessary to remove the nuclei of the oxide film formed on the SAM when the film formation of the oxide film on the insulating film has progressed to some extent. After the nuclei of the oxide film on the SAM are removed, the SAM is replenished on the metal film, and the oxide film is formed again on the insulating film. If the SAM remains on the metal film after the nucleus of the oxide film on the SAM is removed, the SAM remaining on the metal film is removed, the SAM is replenished on the metal film, and the SAM is replenished again. An oxide film is formed on the insulating film. By repeating the formation of the oxide film, the removal of the nuclei on the SAM, and the replenishment of the SAM in this order, an oxide film having a desired thickness can be formed on the insulating film.

Here, the core of the oxide film formed on the SAM can be removed by etching with, for example, a fluorocarbon-based gas. However, since the fluorocarbon-based gas is supplied to the entire substrate, the oxide film formed on the insulating film is also etched, and the film thickness of the oxide film is reduced. Therefore, even if the film thickness of the oxide film, the removal of the nuclei on the SAM, and the replenishment of the SAM are repeated, the film thickness of the oxide film formed on the insulating film does not easily reach the desired film thickness. Therefore, it is required to improve the productivity of the entire process for selectively forming an oxide film having a desired film thickness only on the insulating film.

Therefore, the present disclosure provides a technique capable of improving the productivity of a semiconductor device using selective film formation.

(First Embodiment)
[Film formation system]
FIG. 1 is a schematic view showing an example of a film forming system 100 according to an embodiment of the present disclosure. The film forming system 100 includes a SAM supply device 200, a film forming device 300, a plasma processing device 400, and a plasma processing device 500. These devices are connected to the four side walls of the vacuum transfer chamber 101 having a heptagonal planar shape via a gate valve G, respectively. The film forming system 100 is a multi-chamber type vacuum processing system. The inside of the vacuum transfer chamber 101 is exhausted by a vacuum pump and maintained at a predetermined degree of vacuum. The film forming system 100 uses the SAM supply device 200, the film forming device 300, the plasma processing device 400, and the plasma processing device 500 to expose the first film and the second film on the surface of the substrate W. A third film is selectively formed on the film 2.

The SAM supply device 200 forms a SAM in the region of the first film of the substrate W by supplying the gas of the organic compound for forming the SAM to the surface of the substrate W. The SAM in the present embodiment has a function of adsorbing on the surface of the first film and suppressing the film formation of the third film.

In the present embodiment, the organic compound for forming SAM has a functional group containing fluorine and carbon. The organic compound for forming the SAM connects, for example, a binding functional group adsorbed on the surface of the first film, a functional functional group containing fluorine and carbon, and a binding functional group and a functional functional group. It is an organic compound having an alkyl chain.

When the first film is, for example, gold or copper, a thiol compound represented by the general formula "R-SH" can be used as the organic compound for forming the SAM. Here, "R" includes a fluorine atom and a carbon atom. Thiol compounds have the property of adsorbing on the surface of metals such as gold and copper and not on the surface of oxides and carbon. Examples of such thiol compounds include CF ₃ (CF ₂ ) ₁₅ CH ₂ CH ₂ SH, CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ SH, CF ₃ (CF ₂ ) ₅ CH ₂ CH ₂ SH, HS. -(CH ₂ ) _11- O- (CH ₂ ) _2- (CF ₂ ) _5- _{CF 3} or HS- (CH ₂ ) _11- O-CH _2- C ₆ F ₅ etc. can be used.

When the first film is, for example, a silicon nitride film, the organic compound for forming the SAM is represented by, for example, the general formula "R-Si (OCH ₃ ) ₃ " or "R-SiCl ₃ ". Organic silane compounds can be used. When the first membrane is, for example, aluminum oxide, the organic compound for forming the SAM is, for example, a phosphonic acid compound represented by the _{general formula "RP (= O) (OH) 2".} Can be used. When the first membrane is, for example, tantalum pentoxide, an isocyanate compound represented by the general formula "RN = C = O" may be used as the organic compound for forming the SAM. it can.

In the present embodiment, the first membrane is a membrane on which SAM is more easily adsorbed than the second membrane. Further, the third membrane is a membrane that is easier to form a volatile compound by binding with fluorine and carbon contained in SAM than the first membrane. As such a combination of the first film, the second film, the third film, and the material of the SAM, for example, the combinations shown in Tables 1 to 4 below can be considered.

In the combinations shown in Tables 1 to 4, the material of the first film and the material of the second film are different, and the material of the first film and the material of the third film are different. It is assumed that.

The film forming apparatus 300 forms a third film on the second film of the substrate W on which the SAM is formed by the SAM supply device 200. In the present embodiment, the film forming apparatus 300 forms a third film on the region of the second film of the substrate W by ALD (Atomic Layer Deposition) using the raw material gas and the reaction gas. As the raw material gas, for example, a gas such as silane chloride or dimethylsilane chloride can be used. As the reaction gas, for example, H ₂ O gas or N ₂ O gas can be used.

The plasma processing apparatus 400 irradiates at least one of ions and active species on the substrate W on which the third film is formed by the film forming apparatus 300. In the present embodiment, the plasma processing apparatus 400 irradiates the substrate W with ions and active species contained in the plasma by exposing the substrate W to plasma of a rare gas such as Ar gas. The plasma may be generated by using a plurality of types of rare gases (for example, He gas and Ar gas).

The plasma processing device 500 removes the SAM remaining on the first film by further exposing the surface of the substrate W irradiated with ions and active species by the plasma processing device 400 to plasma. In the present embodiment, the plasma processing apparatus 500 removes the SAM remaining on the first film by, for example, generating a hydrogen gas plasma and exposing the surface of the substrate W to the hydrogen gas plasma. The plasma processing apparatus 500 may use plasma of another gas such as oxygen gas to remove the SAM remaining on the first film. Further, the SAM remaining on the first film may be removed by using a highly reactive gas such as ozone gas without using plasma.

Three load lock chambers 102 are connected to the other three side walls of the vacuum transfer chamber 101 via a gate valve G1. An air transport chamber 103 is provided on the opposite side of the vacuum transport chamber 101 with the load lock chamber 102 in between. Each of the three load lock chambers 102 is connected to the atmospheric transport chamber 103 via a gate valve G2. The load lock chamber 102 controls the pressure between the atmospheric pressure and the vacuum when the substrate W is transported between the atmospheric transport chamber 103 and the vacuum transport chamber 101.

Three ports 105 for mounting a carrier (FOUP (Front-Opening Unified Pod), etc.) C for accommodating the substrate W are provided on the side surface of the air transport chamber 103 opposite to the side surface on which the gate valve G2 is provided. Has been done. Further, an alignment chamber 104 for aligning the substrate W is provided on the side wall of the air transport chamber 103. A downflow of clean air is formed in the air transport chamber 103.

A transfer mechanism 106 such as a robot arm is provided in the vacuum transfer chamber 101. The transport mechanism 106 transports the substrate W between the SAM supply device 200, the film forming device 300, the plasma processing device 400, the plasma processing device 500, and each load lock chamber 102. The transport mechanism 106 has two independently

movable arms

107a and 107b.

A transport mechanism 108 such as a robot arm is provided in the atmospheric transport chamber 103. The transport mechanism 108 transports the substrate W between each carrier C, each load lock chamber 102, and an alignment chamber 104.

The film forming system 100 includes a control device 110 having a memory, a processor, and an input / output interface. The memory stores a program executed by the processor and a recipe including conditions for each process. The processor executes a program read from the memory and controls each part of the film forming system 100 via the input / output interface based on the recipe stored in the memory.

[Film film method]
FIG. 2 is a flowchart showing an example of the film forming method according to the first embodiment. In the present embodiment, for example, by the film forming system 100 shown in FIG. 1, in the substrate W in which the first film and the second film are exposed on the surface, a third film is selectively formed on the second film. A film is formed. The film forming method shown in the flowchart of FIG. 2 is realized by the control device 110 controlling each part of the film forming system 100. Hereinafter, an example of the film forming method according to the first embodiment will be described with reference to FIGS. 3 to 8.

First, the preparation process is executed (S10). In the preparation step of step S10, for example, as shown in FIG. 3, the substrate W having the first film 11 and the second film 12 on the base material 10 is prepared. FIG. 3 is a cross-sectional view showing an example of the substrate W prepared in the preparation step of the first embodiment. In the present embodiment, the base material 10 is, for example, silicon, the first film 11 is a metal film such as copper, and the second film 12 is an insulating film such as a silicon oxide film.

The substrate W prepared in step S10 is accommodated in the carrier C and set in the port 105. Then, it is taken out from the carrier C by the transport mechanism 108, passed through the alignment chamber 104, and then carried into one of the load lock chambers 102. Then, after the inside of the load lock chamber 102 is evacuated, the substrate W is carried out from the load lock chamber 102 by the transport mechanism 106 and carried into the SAM supply device 200.

Next, the first film forming step is executed (S11). In the first film forming step of step S11, the gas of the organic compound for forming the SAM is supplied into the SAM supply device 200 into which the substrate W is carried. The molecules of the organic compound supplied into the SAM supply device 200 are not adsorbed on the surface of the second film 12 on the substrate W, but are adsorbed on the surface of the first film 11 and are adsorbed on the surface of the first film 11. SAM is formed in. The main processing conditions in the first film forming step of step S11 are as follows, for example.
Temperature of substrate W: 100 to 350 ° C (preferably 150 ° C)
Pressure: 1-100 Torr (preferably 50 Torr)
Flow rate of gas of organic compound: 50-500 sccm (preferably 250 sccm)
Processing time: 10 to 300 seconds (preferably 30 seconds)

As a result, the state of the substrate W becomes, for example, as shown in FIG. FIG. 4 is a cross-sectional view showing an example of the substrate W after the SAM 13 is formed on the first film 11 in the first embodiment. After the process of step S11 is executed, the substrate W is carried out from the SAM supply device 200 by the transport mechanism 106 and carried into the film forming apparatus 300.

Next, the second film forming step is executed (S12). In the second film forming step of step S12, in the film forming apparatus 300 to which the substrate W is carried in, a third film such as an oxide film is formed on the substrate W by ALD. In the present embodiment, the third film formed on the substrate W by ALD is, for example, a silicon oxide film. In ALD, the ALD cycle including the adsorption step, the first purging step, the reaction step, and the second purging step is repeated a predetermined number of times.

In the adsorption step, a raw material gas such as a gas of silane chloride is supplied into the film forming apparatus 300. As a result, the molecules of the raw material gas are chemically adsorbed on the surface of the second film 12. However, the molecules of the raw material gas are hardly adsorbed on the SAM 13. The main treatment conditions in the adsorption step are as follows, for example.
Temperature of substrate W: 100 to 350 ° C. (preferably 200 ° C.)
Pressure: 1-10 Torr (preferably 5 Torr)
Flow rate of raw material gas: 10-500 sccm (preferably 250 sccm)
Processing time: 0.3 to 10 seconds (preferably 1 second)

In the first purging step, an inert gas such as nitrogen gas is supplied into the film forming apparatus 300, so that molecules of the raw material gas excessively adsorbed on the second film 12 are removed. The main processing conditions in the first purging step are as follows, for example.
Temperature of substrate W: 100 to 350 ° C. (preferably 200 ° C.)
Pressure: 1-10 Torr (preferably 5 Torr)
Flow rate of inert gas: 500-5000 sccm (preferably 2000 sccm)
Processing time: 0.3 to 10 seconds (preferably 5 seconds)

In the reaction step, in the deposition apparatus 300, for example, be reacted gas supply, such as the H ₂ O gas, the molecules of the reaction gas and the molecules of the adsorbed raw material gas on the second film 12 reacts, the second A silicon oxide film (third film 14) is formed on the film 12. At this time, since there are almost no molecules of the raw material gas on the SAM 13, the third film 14 is hardly formed on the SAM 13. The main treatment conditions in the reaction step are as follows, for example.
Temperature of substrate W: 100 to 350 ° C. (preferably 200 ° C.)
Pressure: 1-10 Torr (preferably 5 Torr)
Flow rate of reaction gas: 100-2000 sccm (preferably 250 sccm)
Processing time: 0.3 to 10 seconds (preferably 1 second)

In the second purging step, the unreacted raw material gas molecules and the like on the second film 12 are removed by supplying an inert gas such as nitrogen gas into the film forming apparatus 300. The main processing conditions in the second purging step are the same as the processing conditions in the first purging step described above.

By repeating the ALD cycle including the adsorption step, the first purging step, the reaction step, and the second purging step a predetermined number of times, a third film is formed on the second film 12, for example, as shown in FIG. 14 is formed. FIG. 5 is a cross-sectional view showing an example of the substrate W after the third film 14 is formed in the first embodiment.

The region of SAM 13 on the first membrane 11 is also exposed to the raw material gas and the reaction gas. Further, the ability of the SAM 13 to suppress the film formation of the third film 14 is not perfect. Therefore, by repeating the ALD cycle, for example, as shown in FIG. 5, the nucleus 15 of the third film 14 may be formed on the SAM 13.

Even after the nucleus 15 of the third film 14 is formed on the SAM 13, if the above ALD cycle is repeated, the nucleus 15 grows and eventually the third film 14 is also formed on the SAM 13. In order to prevent this, it is necessary to remove the nucleus 15 formed on the SAM 13 before the nucleus 15 grows on the third film 14. After the processing of step S12 is executed, the substrate W is carried out from the film forming apparatus 300 by the conveying mechanism 106 and carried into the plasma processing apparatus 400.

Next, the first removal step is executed (S13). The first removal step of step S13 is performed by, for example, the plasma processing apparatus 400 as shown in FIG. FIG. 6 is a schematic cross-sectional view showing an example of the plasma processing apparatus 400 used in the first removing step. The plasma processing apparatus 400 in this embodiment is, for example, a capacitively coupled parallel plate plasma processing apparatus. The plasma processing apparatus 400 has, for example, a processing container 410 whose surface is formed of anodized aluminum or the like and in which a substantially cylindrical space is formed. The processing container 410 is grounded for security.

A substantially cylindrical stage 420 on which the substrate W is placed is provided in the processing container 410. The stage 420 is made of, for example, aluminum or the like. A high frequency power supply 421 is connected to the stage 420. The high frequency power supply 421 supplies high frequency power of a predetermined frequency (for example, 400 kHz to 13.5 MHz) used for attracting (bias) ions to the stage 420.

An exhaust port 411 is provided at the bottom of the processing container 410. An exhaust device 413 is connected to the exhaust port 411 via an exhaust pipe 412. The exhaust device 413 has a vacuum pump such as a turbo molecular pump, and can reduce the pressure inside the processing container 410 to a desired degree of vacuum.

An opening 414 for carrying in and out the substrate W is formed on the side wall of the processing container 410, and the opening 414 is opened and closed by the gate valve G.

A shower head 430 is provided above the stage 420 so as to face the stage 420. The shower head 430 is supported on the upper part of the processing container 410 via the insulating member 415. The stage 420 and the shower head 430 are provided in the processing container 410 so as to be substantially parallel to each other.

The shower head 430 has a top plate holding portion 431 and a top plate 432. The top plate holding portion 431 is formed of, for example, aluminum whose surface has been anodized, and the top plate 432 is detachably supported under the top plate holding portion 431.

A diffusion chamber 433 is formed in the top plate holding portion 431. An introduction port 436 communicating with the diffusion chamber 433 is formed in the upper part of the top plate holding portion 431, and a plurality of flow paths 434 communicating with the diffusion chamber 433 are formed in the bottom portion of the top plate holding portion 431. There is. A gas supply source 438 is connected to the introduction port 436 via a pipe. The gas supply source 438 is a source of a rare gas such as Ar gas. Rare gas is an example of treated gas.

The top plate 432 is formed with a plurality of through holes 435 that penetrate the top plate 432 in the thickness direction. One through-hole 435 communicates with one flow path 434. The rare gas supplied from the gas supply source 438 into the diffusion chamber 433 via the introduction port 436 diffuses in the diffusion chamber 433 and showers into the processing container 410 through the plurality of flow paths 434 and the through ports 435. Is supplied to.

A high frequency power supply 437 is connected to the top plate holding portion 431 of the shower head 430. The high-frequency power supply 437 supplies high-frequency power of a predetermined frequency used for generating plasma to the top plate holding unit 431. The frequency of the high frequency power used to generate the plasma is, for example, a frequency in the range of 450 kHz to 2.5 GHz. The high-frequency power supplied to the top plate holding portion 431 is radiated into the processing container 410 from the lower surface of the top plate holding portion 431. The rare gas supplied into the processing container 410 is turned into plasma by the high frequency power radiated to the processing container 410. Then, the active species contained in the plasma is irradiated on the surface of the substrate W. Further, the ions contained in the plasma are drawn into the surface of the substrate W by the bias power supplied to the stage 420 by the high frequency power supply 421, and are irradiated on the surface of the substrate W.

By irradiating the substrate W with at least one of an ion and an active species, the SAM 13 on the first film 11 is excited, and the fluorine and carbon contained in the SAM 13 and the third film formed on the SAM 13 are excited. 14 nuclei 15 react. Then, the nucleus 15 of the third film 14 formed on the SAM 13 becomes a volatile silicon fluoride compound and is removed from the SAM 13. The main processing conditions in the first removing step of step S13 are as follows, for example.
Temperature of substrate W: 30 to 350 ° C (preferably 200 ° C)
Pressure: Several mTorr-100 Torr (preferably 10 mTorr)
Rare gas flow rate: 10-1000 sccm (preferably 100 sccm)
High frequency power for plasma generation: 100-5000W (preferably 2000W)
High frequency power for bias: 10 to 1000 W (preferably 100 W)
Processing time: 1 to 300 seconds (preferably 30 seconds)

As a result, the state of the substrate W becomes, for example, as shown in FIG. FIG. 7 is a cross-sectional view showing an example of the substrate W after the core 15 of the third film 14 on the SAM 13 has been removed in the first embodiment. When the surface of the substrate W is irradiated with at least one of the ions contained in the plasma and the active species, a part of the SAM 13 on the first film 11 is decomposed, and the nucleus 15 of the third film 14 on the SAM 13 is decomposed. And the nucleus 15 of the third membrane 14 on the SAM 13 is removed. On the other hand, even if the third film 14 is irradiated with at least one of an ion and an active species, the third film 14 is hardly scraped and the film thickness of the third film 14 is almost unchanged. After the processing of step S13 is executed, the substrate W is carried out from the plasma processing device 400 by the transport mechanism 106 and carried into the plasma processing device 500.

Next, the second removal step is executed (S14). In the second removal step of step S14, for example, a plasma of hydrogen gas is generated in the plasma processing apparatus 500 into which the substrate W is carried. As the plasma processing apparatus 500, for example, an apparatus having the same structure as the plasma processing apparatus 400 described with reference to FIG. 6 can be used. The main processing conditions in the second removing step of step S14 are as follows, for example.
Temperature of substrate W: 30 to 350 ° C (preferably 200 ° C)
Pressure: Several mTorr-100 Torr (preferably 50 Torr)
Hydrogen gas flow rate: 10-1000 sccm (preferably 200 sccm)
High frequency power for plasma generation: 100-5000W (preferably 2000W)
High frequency power for bias: 10 to 1000 W (preferably 100 W)
Processing time: 1 to 300 seconds (preferably 30 seconds)

As a result, all the SAM 13 remaining on the first film 11 is removed, and the state of the substrate W becomes, for example, FIG. FIG. 8 is a cross-sectional view showing an example of the substrate W after the SAM 13 on the first film 11 has been removed in the first embodiment.

Next, it is determined whether or not the processes of steps S11 to S14 have been executed a predetermined number of times (S15). The predetermined number of times is the number of times that the processes of steps S11 to S14 are repeated until a third film 14 having a predetermined thickness is formed on the second film 12. If steps S11 to S14 have not been executed a predetermined number of times (S15: No), the process shown in step S11 is executed again.

On the other hand, when steps S11 to S14 are executed a predetermined number of times (S15: Yes), the substrate W is carried out from the plasma processing device 500 by the transport mechanism 106 and carried into one of the load lock chambers 102. Then, after the inside of the load lock chamber 102 is returned to the atmospheric pressure, the substrate W is carried out from the load lock chamber 102 by the transport mechanism 108 and returned to the carrier C. Then, the film forming method shown in this flowchart is completed.

Here, if the nuclei 15 of the third film 14 formed on the SAM 13 are removed by dry etching using a fluorocarbon-based gas, the nuclei 15 are removed, but a film is formed on the second film 12. The third film 14 that has been formed is also etched. Therefore, it takes a long time to form the third film 14 having a predetermined thickness on the second film 12, and it is difficult to improve the productivity of the semiconductor device using the substrate W.

On the other hand, in the present embodiment, in step S11, SAM13 containing fluorine and carbon is selectively formed on the first film 11, and in step S13, at least one of ions and active species is formed on the entire substrate W. Irradiate. As a result, the SAM 13 on the first membrane 11 is decomposed, and the nucleus 15 of the third membrane 14 on the SAM 13 is removed as a volatile silicon fluoride compound by the fluorine and carbon contained in the SAM 13.

On the other hand, since the third film 14 formed on the second film 12 has almost no fluorine atoms and carbon atoms, even if at least one of an ion and an active species is irradiated, the third film is formed. 14 is hardly etched. Therefore, a third film 14 having a predetermined thickness can be formed on the second film 12 at an early stage, and the productivity of the semiconductor device using the substrate W can be improved.

The first embodiment has been described above. As described above, the film forming method in the present embodiment is a film forming method for selectively forming a film on the substrate W, and includes a preparation step, a first film forming step, and a second film forming step. , The first removal step and the like. In the preparatory step, the substrate W on which the first film 11 and the second film 12 are exposed is prepared. In the first film forming step, a compound for forming a self-assembled monolayer having a functional group containing fluorine and carbon and suppressing the formation of the third film 14 is supplied onto the substrate W. As a result, the SAM 13 is formed on the first film 11. In the second film forming step, the third film 14 is formed on the second film 12. In the first removal step, the surface of the substrate W is irradiated with at least one of ions and active species to remove the third film 14 formed in the vicinity of the SAM 13. Further, the third film 14 is a film that is easier to form a volatile compound by binding with fluorine and carbon contained in SAM 13 than the first film 11. Thereby, the productivity of the semiconductor device using the selective film formation can be improved.

Further, in the first removal step in the above-described embodiment, the surface of the substrate W is irradiated with at least one of an ion and an active species, so that the core 15 of the third film 14 formed on the SAM 13 is formed. Will be removed. Thereby, the productivity of the semiconductor device using the selective film formation can be improved.

Further, the film forming method in the above-described embodiment further includes a second removing step of removing the SAM 13 on the first film 11, which is executed after the first removing step. Further, the first film forming step, the second film forming step, the first removing step, and the second removing step are repeated a plurality of times in this order. As a result, a third film 14 having a desired thickness can be quickly formed on the second film 12 by selective film formation.

Further, in the first removing step in the above-described embodiment, the surface of the substrate W is exposed to the plasma of the processing gas, so that at least one of the ions and the active species contained in the plasma is irradiated on the surface of the substrate W. .. The processing gas is, for example, a rare gas. As a result, the surface of the substrate W can be efficiently irradiated with at least one of ions and active species.

Further, in the above-described embodiment, the first film 11 may be, for example, a metal film, the second film 12 may be, for example, an insulating film, and the third film 14 may be, for example, an oxide film. It may be. As a result, a third film 14 having a desired thickness can be quickly formed on the second film 12 by selective film formation.

Further, in the above-described embodiment, the organic compound for forming the SAM 13 is an organic compound having a binding functional group adsorbed on the surface of the first film 11 and a functional functional group containing fluorine and carbon. .. Specifically, the organic compound for forming SAM 13 is, for example, a thiol-based compound, an organic silane-based compound, a phosphonic acid-based compound, or an isocyanate-based compound. As a result, the SAM 13 can be selectively formed on the surface of the first film 11.

(Second Embodiment)
FIG. 9 is a flowchart showing an example of the film forming method in the second embodiment. In the present embodiment, in the substrate W in which the first film and the second film are exposed on the surface by the film forming system 100 illustrated in FIG. 1, a third film is selectively formed on the second film. Is formed. The film forming method illustrated in the flowchart of FIG. 9 is realized by the control device 110 controlling each part of the film forming system 100. Hereinafter, an example of the film forming method according to the second embodiment will be described with reference to FIGS. 10 to 16. The plasma processing apparatus 500 is not used in the film forming method in this embodiment.

First, the preparation process is executed (S20). In the preparation step of step S20, for example, as shown in FIG. 10, the substrate W in which the barrier film 51 and the metal wiring 50 are embedded in the groove of the interlayer insulating film 52 formed of the Low-k material is prepared. FIG. 10 is a cross-sectional view showing an example of the substrate W prepared in the preparation step of the second embodiment. The metal wiring 50 is an example of the first film, and the barrier film 51 and the interlayer insulating film 52 are examples of the second film. In the present embodiment, the metal wiring 50 is, for example, copper, the barrier film 51 is, for example, tantalum nitride, and the interlayer insulating film 52 is, for example, a silicon oxide film.

The substrate W prepared in step S20 is accommodated in the carrier C and set in the port 105. Then, it is taken out from the carrier C by the transport mechanism 108, passed through the alignment chamber 104, and then carried into one of the load lock chambers 102. Then, after the inside of the load lock chamber 102 is evacuated, the substrate W is carried out from the load lock chamber 102 by the transport mechanism 106 and carried into the SAM supply device 200.

Next, the first film forming step is executed (S21). In the first film forming step of step S21, the gas of the organic compound for forming the SAM is supplied into the SAM supply device 200 into which the substrate W is carried. As the organic compound for forming the SAM, for example, a thiol-based compound having a functional group containing a carbon atom and a fluorine atom can be used. The molecules of the organic compound supplied into the SAM supply device 200 are not adsorbed on the surfaces of the barrier film 51 and the interlayer insulating film 52 on the substrate W, but are adsorbed on the surface of the metal wiring 50, and are adsorbed on the metal wiring 50. Form SAM. The main processing conditions in the first film forming step of step S21 are the same as the main processing conditions in the first film forming step of step S11 of the first embodiment.

As a result, the state of the substrate W becomes, for example, as shown in FIG. FIG. 11 is a cross-sectional view showing an example of the substrate W after the SAM 53 is formed on the metal wiring 50 in the second embodiment. After the process of step S21 is executed, the substrate W is carried out from the SAM supply device 200 by the transport mechanism 106 and carried into the film forming apparatus 300.

Next, the second film forming step is executed (S22). In the second film forming step of step S22, the dielectric film 54 is formed on the substrate W by ALD in the film forming apparatus 300 to which the substrate W is carried. The dielectric film 54 is an example of a third film. In this embodiment, the dielectric film 54 is, for example, aluminum oxide. In ALD, the ALD cycle including the adsorption step, the first purging step, the reaction step, and the second purging step is repeated a predetermined number of times.

In the adsorption step, a raw material gas such as TMA (trimethylaluminum) gas is supplied into the film forming apparatus 300. As a result, the molecules of the raw material gas are chemically adsorbed on the surfaces of the barrier film 51 and the interlayer insulating film 52. However, the molecules of the raw material gas are hardly adsorbed on the SAM 53. The main treatment conditions in the adsorption step are as follows, for example.
Temperature of substrate W: 80 to 250 ° C. (preferably 150 ° C.)
Pressure: 0.1-10 Torr (preferably 3 Torr)
Flow rate of raw material gas: 1 to 300 sccm (preferably 50 sccm)
Processing time: 0.1 to 5 seconds (preferably 0.2 seconds)

In the first purging step, the raw material gas excessively adsorbed on the barrier film 51 and the interlayer insulating film 52 by supplying a rare gas such as argon gas or an inert gas such as nitrogen gas into the film forming apparatus 300. Molecules are removed. The main processing conditions in the first purging step are as follows, for example.
Temperature of substrate W: 80 to 250 ° C. (preferably 150 ° C.)
Pressure: 0.1-10 Torr (preferably 3 Torr)
Flow rate of inert gas: 5 to 15 slm (preferably 10 slm)
Processing time: 0.1 to 15 seconds (preferably 2 seconds)

In the reaction step, in the deposition apparatus 300, for example, it is reacted gas supply, such as the H ₂ O gas, and molecules adsorbed material gas reacts on the molecules of the reaction gas and the barrier film 51 and the interlayer insulating film 52, Aluminum oxide (dielectric film 54) is formed on the barrier film 51 and the interlayer insulating film 52. At this time, since there are almost no molecules of the raw material gas on the SAM 53, the dielectric film 54 is hardly formed on the SAM 53. The main treatment conditions in the reaction step are as follows, for example.
Temperature of substrate W: 80 to 250 ° C. (preferably 150 ° C.)
Pressure: 0.1-10 Torr (preferably 3 Torr)
Flow rate of reaction gas: 10-500 sccm (preferably 100 sccm)
Processing time: 0.1-5 seconds (preferably 0.5 seconds)

In the second purging step, rare gas such as argon gas and inert gas such as nitrogen gas are supplied into the film forming apparatus 300, so that unreacted raw material gas molecules and the like on the substrate W are removed. .. The main processing conditions in the second purging step are the same as the processing conditions in the first purging step described above.

By repeating the ALD cycle including the adsorption step, the first purging step, the reaction step, and the second purging step a predetermined number of times, the dielectric is dielectric on the barrier film 51 and the interlayer insulating film 52, for example, as shown in FIG. A body film 54 is formed. FIG. 12 is a cross-sectional view showing an example of the substrate W after the dielectric film 54 is formed in the second embodiment.

Here, the region of the SAM 53 on the metal wiring 50 is also exposed to the raw material gas and the reaction gas. Further, the ability of the SAM 53 to suppress the film formation of the dielectric film 54 is not perfect. Therefore, by repeating the above ALD cycle, a nucleus of the dielectric film 54 may be formed on the SAM 53, for example, as shown in FIG. Further, in the process of growing the dielectric film 54 by repeating the ALD cycle, the dielectric film 54 also grows in the lateral direction, and as shown in FIG. 12, for example, a part of the dielectric film 54 is a metal wiring 50. Protrude into the area. As a result, the width of the opening of the dielectric film 54 becomes a width ΔW1 narrower than the width ΔW0 of the region of the metal wiring 50.

Next, the first removal step is executed (S23). The first removal step of step S23 is performed by, for example, the plasma processing apparatus 400 as shown in FIG. The plasma processing device 400 of the present embodiment may not be provided with the high frequency power supply 421. In the first removal step, the processing gas is turned into plasma, and at least one of the ions and active species contained in the plasma is irradiated on the substrate W. As a result, the SAM 53 on the metal wiring 50 is excited, the fluorine and carbon contained in the SAM 53 react with the core of the dielectric film 54 formed on the SAM 53, and the core of the dielectric film 54 is volatile. It becomes a fluorine compound and is removed from the SAM53.

Further, by irradiating at least one of the ions and the active species contained in the plasma on the substrate W, the SAM 53 adjacent to the dielectric film 54 is excited, and the active species having fluorine and carbon contained in the SAM 53 is generated. To. Then, the active species having fluorine and carbon reacts with the side portion of the dielectric film 54 adjacent to the SAM 53. As a result, the side portion of the dielectric film 54 protruding into the region of the metal wiring 50 is removed as a volatile fluorine compound or a volatile compound containing fluorine and carbon.

As a result, as shown in FIG. 13, for example, the width of the opening of the dielectric film 54 is widened to a width ΔW2 wider than the width ΔW0 of the region of the metal wiring 50. FIG. 13 is a cross-sectional view showing an example of the substrate W after the SAM 53 has been removed in the second embodiment. As a result, when a via connected to the metal wiring 50 is formed in the opening of the dielectric film 54 in the subsequent step, the width of the via can be made wider than the width of the metal wiring 50, and the width of the via can be increased. It is possible to suppress an increase in the resistance value. Since the active species produced by exciting the SAM 53 has a short lifetime, it is deactivated before reaching the upper surface of the dielectric film 54. Therefore, the upper surface of the dielectric film 54 is hardly etched by the active species generated by exciting the SAM 53.

In the present embodiment, the processing gas used in step S23 is, for example, hydrogen gas. As the treatment gas, as long as it is a hydrogen-containing gas, a gas containing at least one of ammonia gas, hydrazine gas, and hydrocarbon gas such as methane can be used in addition to hydrogen gas. By executing step S23, the SAM 53 on the metal wiring 50 is removed. Therefore, in the present embodiment, the second removal step for the purpose of removing the SAM 53 is not executed.

The main processing conditions in the first removing step of step S23 are as follows, for example.
Temperature of substrate W: 50 to 300 ° C (preferably 150 ° C)
Pressure: 0.1 Torr to 50 Torr (preferably 2 Torr)
Flow rate of processing gas: 200-3000 sccm (preferably 1000 sccm)
High frequency power for plasma generation: 50-1000W (preferably 200W)
Processing time: 1-60 seconds (preferably 10 seconds)

Next, it is determined whether or not the processes of steps S21 to S23 have been executed a predetermined number of times (S24). The predetermined number of times is the number of times that the processes of steps S21 to S23 are repeated until the dielectric film 54 having a predetermined thickness is formed on the interlayer insulating film 52. When steps S21 to S23 have not been executed a predetermined number of times (S24: No), the process shown in step S21 is executed again, so that the SAM 53 is formed on the surface of the metal wiring 50, for example, as shown in FIG. A film is formed.

Then, by executing the process shown in step S22 again, the dielectric film 54 is further formed on the barrier film 51 and the dielectric film 54. As a result, for example, as shown in FIG. 15, a part of the dielectric film 54 protrudes again into the region of the metal wiring 50, and the width of the opening of the dielectric film 54 is larger than the width ΔW0 of the region of the metal wiring 50. It has a narrow width ΔW3.

Then, by executing the process shown in step S23 again, the active species containing fluorine and carbon contained in the SAM 53 protruded into the core of the dielectric film 54 on the SAM 53 and the region of the metal wiring 50. The side portion of the dielectric film 54 is removed. As a result, for example, as shown in FIG. 16, the width of the opening of the dielectric film 54 expands to a width ΔW4 wider than the width ΔW0 of the region of the metal wiring 50.

By repeating steps S21 to S23 in this way, the width of the opening of the dielectric film 54 is maintained wider than the width ΔW0 of the region of the metal wiring 50, and an arbitrary thickness is formed around the metal wiring 50. The dielectric film 54 of the above can be formed.

The second embodiment has been described above. In the first removing step in the present embodiment, the surface of the substrate W is irradiated with at least one of ions and active species to remove the side portion of the dielectric film 54 adjacent to the SAM 53. Thereby, the width of the opening of the dielectric film 54 can be made wider than the width of the region of the metal wiring 50.

Further, in the first removal step in the present embodiment, the surface of the substrate W is exposed to the plasma of the processing gas, so that at least one of the ions and the active species contained in the plasma is irradiated on the surface of the substrate W. The processing gas is, for example, a hydrogen-containing gas. As a result, the surface of the substrate W can be efficiently irradiated with at least one of ions and active species.

[Other]
The technique disclosed in the present application is not limited to the above-described embodiment, and many modifications can be made within the scope of the gist thereof.

For example, in the first embodiment described above, the third film 14 was formed by ALD in the second film forming step of step S12, but the disclosed technique is not limited to this. As another example, in the second film forming step of step S12, the third film 14 may be formed by CVD (Chemical Vapor Deposition).

Further, in the first embodiment described above, in the first removal step of step S13, the substrate W is exposed to the plasma of the rare gas, so that the surface of the substrate W is irradiated with the ions contained in the plasma. The disclosed technology is not limited to this. For example, the surface of the substrate W may be irradiated with ions using a focused ion beam device or the like.

Further, in the first embodiment described above, the film forming system 100 is provided with one SAM supply device 200, one film forming device 300, one plasma processing device 400, and one plasma processing device 500. Is not limited to this. For example, the plasma processing device 400 and the plasma processing device 500 may be realized by one plasma processing device. Further, for example, the film forming system 100 may be provided with a plurality of devices that perform the most time-consuming processing, and the other processing may be realized by one device. For example, when the process of step S11 takes a long time, a plurality of SAM supply devices 200 for performing the process of step S11 may be provided, and one device for performing the processes of S12 to S14 may be provided. As a result, it is possible to reduce the processing waiting time when processing a plurality of substrates W.

Further, in the second embodiment described above, the first film forming step, the second film forming step, and the first removing step are repeatedly executed in this order, but the disclosed technique is limited to this. Absent. For example, as shown in FIG. 17, after the first film forming step (S21), the second film forming step (S22), and the first removing step (S23) are executed, the first film forming step (S30) and the first removal (S31) may be performed one or more times in this order. FIG. 17 is a flowchart showing another example of the film forming method in the second embodiment. The process performed in the first film forming step of step S30 is the same as the process performed in the first film forming step of step S21, and the process performed in the first removing step of step S31 is the process performed in step S23. It is the same as the process performed in the first removal step. In the film forming method illustrated in FIG. 17, a dielectric film 54 having a sufficient thickness is formed in the second film forming step of step S22. Then, by repeating the first film forming step of step S30 and the first removing step of step S31, the width of the opening of the dielectric film 54 can be made wider than the width of the region of the metal wiring 50.

Further, for example, as shown in FIG. 18, a process (S33) for determining whether or not the processes S21 to S23 and the processes S30 to S32 have been repeated a predetermined number of times may be executed. As a result, it is possible to prevent the thickness of the dielectric film 54 from becoming too large in step S22 and the opening of the dielectric film 54 from being blocked.

Further, the processing gas used in the first removal step of the second embodiment described above is a hydrogen-containing gas, but the disclosed technique is not limited to this. For example, the processing gas may contain a rare gas such as argon gas in addition to the hydrogen-containing gas.

It should be considered that the embodiment disclosed this time is an example in all respects and is not restrictive. Indeed, the above embodiments can be embodied in a variety of forms. Further, the above-described embodiment may be omitted, replaced or changed in various forms without departing from the scope of the appended claims and the purpose thereof.

C Carrier G Gate valve W Substrate 10 Substrate 11 First film 12 Second film 13 SAM
14 Third film 15 Nuclear 100 Film formation system 101 Vacuum transfer chamber 102 Load lock chamber 103 Atmospheric transport chamber 104 Alignment chamber 105 Port 106 Transport mechanism 107 Arm 108 Transport mechanism 110 Control device 200 SAM supply device 300 Film formation device 400 Plasma processing Equipment 410 Processing container 411 Exhaust port 412 Exhaust pipe 413 Exhaust device 414 Opening 415 Insulation member 420 Stage 421 High frequency power supply 430 Shower head 431 Top plate holding part 432 Top plate 433 Diffusion chamber 434 Flow path 435 Through port 436 Introduction port 437 High frequency power supply 438 Gas supply source 500 Plasma processing device 50 Metal wiring 51 Barrier film 52 Interlayer insulation film 53 SAM
54 Dielectric film

Claims

In a film forming method in which a film is selectively formed on a substrate,
A preparatory step for preparing a substrate on which the first film and the second film are exposed on the surface, and
By supplying a compound for forming a self-assembled monolayer having a functional group containing fluorine and carbon and suppressing the formation of the third film onto the substrate, the first film is coated. In the first film formation step of forming the self-assembled monolayer,
A second film forming step of forming the third film on the second film, and
A first removal step of removing the third film formed in the vicinity of the self-assembled monolayer by irradiating the surface of the substrate with at least one of an ion and an active species is included.
A film forming method in which the third film is a film that is easier to form a volatile compound by combining with fluorine and carbon contained in the self-assembled monolayer than the first film.
In the first removal step,
The first aspect of the present invention, wherein when the surface of the substrate is irradiated with at least one of an ion and an active species, the nucleus of the third membrane formed on the self-assembled monolayer is removed. Film formation method.
In the first removal step,
The film formation according to claim 1, wherein the side portion of the third film adjacent to the self-assembled monolayer is removed by irradiating the surface of the substrate with at least one of an ion and an active species. Method.
The film forming method according to any one of claims 1 to 3, wherein the first film forming step, the second film forming step, and the first removing step are repeated a plurality of times in this order.
After the first film forming step, the second film forming step, and the first removing step are executed, the first film forming step and the first removing step are performed once or more in this order. The film forming method according to any one of claims 1 to 3, which is carried out.
Further comprising a second removal step of removing the self-assembled monolayer on the first membrane, which is performed after the first removal step.
The first film forming step, the second film forming step, the first removing step, and the second removing step are repeated a plurality of times in this order according to any one of claims 1 to 3. The film forming method described.
In the first removal step, when the surface of the substrate is exposed to the plasma of the processing gas, at least one of the ions and the active species contained in the plasma is irradiated on the surface of the substrate, claims 1 to 6. The film forming method according to any one of the above.
The film forming method according to claim 7, wherein the processing gas contains at least one of a rare gas and a hydrogen-containing gas.
The first film is a metal film and
The second film is an insulating film.
The film forming method according to any one of claims 1 to 8, wherein the third film is an oxide film.
The compound for forming the self-assembled monolayer has claims 1 to 9 having a binding functional group adsorbed on the surface of the first film and a functional functional group containing fluorine and carbon. The film forming method according to any one of the items.
The film forming method according to claim 10, wherein the compound for forming the self-assembled monolayer is a thiol compound, an organic silane compound, a phosphonic acid compound, or an isocyanate compound.