JP5466890B2 - Substrate processing method, substrate processing apparatus, and computer-readable storage medium - Google Patents

Description

  The present invention relates to a substrate processing method, a substrate processing apparatus, and a computer-readable storage medium.

  In the formation of a copper multilayer wiring, it is common to remove the copper oxide formed on the surface of the copper wiring exposed at the bottom of the opening of the interlayer insulation film, so-called preclean, and then form the barrier film It is. As a pre-clean method, a technique of supplying a gas that can remove copper oxide by a chemical reaction with copper oxide, for example, organic acid dry cleaning, has attracted attention. The organic acid dry cleaning is described in Patent Document 1, for example.

JP 2008-78618 A

  However, organic acid dry cleaning requires heat treatment at around 200 ° C. For this reason, the moisture contained in the interlayer insulating film evaporates during the organic acid dry cleaning. When moisture in the interlayer insulating film evaporates, depending on the material of the barrier film, there is a situation that it is difficult to obtain a film thickness necessary for ensuring sufficient barrier properties.

  The present invention has been made in view of the above circumstances, and it is possible to obtain a film thickness for ensuring sufficient barrier properties for the barrier film while suppressing evaporation of moisture in the interlayer insulating film. A substrate processing method capable of processing a substrate at a low temperature, a substrate processing apparatus capable of executing the substrate processing method, and a computer-readable storage medium storing a program for causing the substrate processing apparatus to execute the substrate processing method I will provide a.

In order to solve the above-described problem, a substrate processing method according to a first aspect of the present invention includes a wiring using copper, an opening formed on the wiring and reaching the wiring, and moisture or OH. And a substrate processing method for processing a substrate in which copper oxide is formed on a surface of the wiring exposed at the bottom of the opening, the substrate processing method comprising: (1) the oxidation A step of forming an organic acid copper complex by adsorbing an organic acid to copper; (2) a step of adsorbing a manganese precursor to the interlayer insulating film after the step (1) ; and (3) the substrate. And sublimating the organic acid copper complex, and forming a manganese oxide film on the surface of the interlayer insulating film.

  According to a second aspect of the present invention, there is provided a substrate processing apparatus comprising: a wiring using copper; and an interlayer insulation formed on the wiring, having an opening reaching the wiring, and containing moisture or an OH group A processing unit including at least one processing container for containing a substrate having copper oxide formed on a surface of the wiring exposed at the bottom of the opening, and the at least one processing container. A control unit that controls the processing unit to execute the substrate processing method according to the first aspect with respect to the accommodated substrate.

  A computer-readable storage medium according to a third aspect of the present invention is a computer-readable storage medium that operates on a computer and stores a control program for controlling the substrate processing apparatus. At the time of execution, the substrate processing apparatus is controlled so that the substrate processing method according to the first aspect is performed.

  According to the present invention, the substrate can be processed at a low temperature so that it is possible to obtain a film thickness for ensuring a sufficient barrier property for the barrier film while suppressing the evaporation of moisture in the interlayer insulating film. A substrate processing method, a substrate processing apparatus capable of executing the substrate processing method, and a computer-readable storage medium storing a program for causing the substrate processing apparatus to execute the substrate processing method can be provided.

Sectional drawing which shows roughly the example of 1 structure of the board | substrate which can be used for the substrate processing method concerning one Embodiment of this invention A flow chart showing an example of a substrate processing method concerning one embodiment of this invention Sectional drawing which showed the state of the board | substrate in step 1 roughly Sectional drawing which showed the state of the board | substrate in step 2 roughly Sectional drawing which showed the state of the board | substrate in step 3 roughly Sectional drawing which showed the state of the board | substrate in step 4 roughly Diagram showing the relationship between the thickness of the manganese oxide film and the substrate heating time The top view which shows roughly an example of the processing system which can implement the substrate processing method which concerns on one Embodiment of this invention

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that common parts are denoted by common reference numerals throughout the drawings.

(Barrier film)
As a new barrier film for wiring using copper, there is a CVD-manganese oxide film formed using a cyclopenta manganese precursor. An interlayer insulating film, for example, a CVD-manganese oxide film formed on a CVD-silicon oxide-based insulating film, has a phenomenon called a self limit, in which the film thickness hardly increases after reaching a certain film thickness. It can be seen.

  Furthermore, as a result of the research of the present inventors, when a manganese precursor is adsorbed at a low temperature, for example, at a temperature of 100 ° C. or less on a base, for example, a CVD-silicon oxide insulating film, and reacted with moisture contained in the base, It was confirmed that the thickness of the manganese oxide film can be controlled to be thicker.

  Hereinafter, a substrate processing method when such a manganese oxide film is used as a barrier film for preventing diffusion of metal, in this example, copper, will be described as an embodiment of the present invention.

(Substrate processing method)
FIG. 1 is a cross-sectional view schematically showing a structural example of a substrate that can be used in a substrate processing method according to an embodiment of the present invention.

  As shown in FIG. 1, the substrate 1 is a semiconductor wafer, for example, a silicon wafer. In FIG. 1, illustration of elements such as a silicon wafer and a transistor is omitted, and only the wiring and interlayer insulating film portions formed on the silicon wafer are schematically shown.

  As shown in FIG. 1, a first interlayer insulating film 2 is formed on a silicon wafer (not shown). A material example of the first interlayer insulating film 2 is a CVD-silicon oxide insulating film. An example of the CVD-silicon oxide insulating film is a TEOS film. A groove for forming a wiring is formed in the first interlayer insulating film 2, and a wiring 3 using copper is formed inside the groove. A barrier film 4 is formed around the wiring 3. A second interlayer insulating film 5 is formed on the wiring 3 and the first interlayer insulating film 2. An example of the material of the second interlayer insulating film 5 is a CVD-silicon oxide insulating film. An example of the CVD-silicon oxide insulating film is a TEOS film. The TEOS film contains moisture inside. An opening 6 reaching the wiring 3 is formed in the second interlayer insulating film 5. Copper oxide 7 is formed on the surface of the wiring 3 exposed at the bottom of the opening 6.

  As described above, the substrate processing method according to the embodiment includes the wiring 3 using copper and the interlayer insulating film 5 formed on the wiring 3 and having an opening reaching the wiring 3 and containing moisture. The substrate 1 on which the copper oxide 7 is formed on the surface of the wiring 3 exposed at the bottom of the opening 6 is processed.

  FIG. 2 is a flowchart showing an example of a substrate processing method according to an embodiment of the present invention. 3A to 3D are cross-sectional views schematically showing the state of the substrate 1 in each step.

  First, the substrate 1 is accommodated in a processing container of a substrate processing apparatus (not shown), and processing is started.

  Next, as shown in FIGS. 2 and 3A, an organic acid gas is supplied into the processing container, and the organic acid is adsorbed on the copper oxide 7 to form the organic acid copper complex 8 (step 1). In this example, formic acid (HCOOH) was used as the organic acid gas. An example of specific processing conditions is as follows.

Processing container pressure: 0.1 Pa or more and 10 ⁵ Pa or less
Substrate temperature: Room temperature
Processing chamber atmosphere: Formic acid gas atmosphere
Or formic acid gas atmosphere diluted with inert gas
Processing time: 10sec or more and 600sec or less
Next, as shown in FIGS. 2 and 3B, a manganese precursor gas is supplied into the processing container, and the manganese precursor is adsorbed to the second interlayer insulating film 5 (step 2). In this example, bisethylcyclopentadienyl manganese ((EtCp) ₂ Mn [= Mn (C ₂ H ₅ C ₅ H ₄ ) ₂ ]) gas was used as the manganese precursor gas. An example of specific processing conditions is as follows.

Processing container pressure: 1 Pa or more and 10 ⁵ Pa or less
Substrate temperature: Over room temperature and below 100 ° C
Processing vessel atmosphere: Manganese precursor gas atmosphere
Or manganese precursor gas atmosphere diluted with inert gas
Processing time: 10sec or more and 600sec or less
Next, as shown in FIGS. 2 and 3C, an inert gas is supplied into the processing container, the substrate 1 is heated, the organic acid copper complex 8 is sublimated, and the surface of the second layer interlayer insulating film 5 is formed. A manganese oxide film 9 is formed. In this example, argon (Ar) gas was used as the inert gas. An example of specific processing conditions is as follows.

Processing container pressure: 0.1 Pa or more and 10 ⁵ Pa or less
Substrate temperature: Over 100 ° C and below 200 ° C
Atmosphere in processing container: Inert gas atmosphere
Processing time: 10sec or more and 600sec or less
Next, as shown in FIGS. 2 and 3D, a copper source gas is supplied into the processing vessel, and copper or a copper alloy is formed on the wiring 3 and the second interlayer insulating film 5 exposed at the bottom of the opening 6. A film 10 is formed. In this example, Cu (hfac) TMVS, which is a beta diketone copper complex, was used as the copper source gas. An example of specific processing conditions is as follows.

Processing vessel internal pressure: 0.1 Pa or more and 10 ³ Pa or less
Substrate temperature: 100 ° C or higher and 200 ° C or lower
Processing vessel atmosphere: Copper source gas atmosphere
Or copper source gas atmosphere diluted with inert gas
Processing time: 10sec or more and 600sec or less
Thus, the substrate processing method according to one embodiment of the present invention is completed.

  According to the substrate processing method according to the one embodiment, an organic acid is adsorbed on the copper oxide 7 to form the organic acid copper complex 8, and a manganese precursor is adsorbed on the second layer interlayer insulating film 5. Is heated to sublimate the organic acid copper complex 8, and a manganese oxide film 9 is formed on the surface of the second interlayer insulating film 5. As described above, after the organic acid adsorption to the copper oxide 7 and the manganese precursor adsorption to the interlayer insulating film 5 are performed, the substrate 1 is heated. 5 is not exposed to high temperature processing, for example, high temperature processing exceeding 100 ° C. For this reason, evaporation of moisture can be suppressed from the interlayer insulating film 5, and a manganese oxide film 9 having a film thickness for ensuring sufficient barrier properties can be formed as a barrier film. In particular, in this example, organic acid adsorption to the copper oxide 7 is performed at room temperature. For this reason, the evaporation of moisture from the interlayer insulating film 5 is further suppressed.

  Further, the organic acid copper complex 8 on the wiring 3 is sublimated and removed by heating the substrate 1 in Step 3. Further, the manganese precursor can be removed from the wiring 3 by sublimating the organic acid copper complex 8. For this reason, the formation of the manganese oxide film 9 on the wiring 3 is suppressed. Therefore, it is suppressed that the manganese oxide film 9 that is an insulator is interposed between the wiring 3 and the copper or copper alloy film 10, and the contact resistance between the wiring 3 and the copper or copper alloy film 10 can be reduced. Is possible. Reducing the contact resistance between the wiring 3 and the copper or copper alloy film 10 is advantageous for manufacturing a semiconductor integrated circuit device that will be further miniaturized in the future.

  The contact resistance can be reduced by sublimating the organic acid copper complex 8 and forming the manganese oxide film 9 as shown in this example when the copper or copper alloy film 10 is formed on the wiring 3. Can be obtained better by forming the copper or copper alloy film 10 without exposing the film to the atmosphere.

  FIG. 4 is a diagram showing the relationship between the thickness of the manganese oxide film and the temperature raising time of the substrate.

  As shown in FIG. 4, when the temperature of the substrate 1 is raised before supplying the manganese precursor gas, the thickness of the manganese oxide film 9 decreases from about 4.0 nm as the temperature raising time becomes longer. When the temperature rise time exceeds about 300 seconds, the film thickness becomes substantially constant at about 0.8 nm regardless of the temperature rise time.

  The manganese oxide film thickness is measured with a transmission electron microscope (TEM).

  As shown in FIG. 4, by raising the temperature of the substrate 1 as performed before supplying the manganese precursor gas, for example, 300 sec or less, the film thickness is sufficient to ensure a sufficient barrier property. A manganese oxide film 9 can be obtained.

  Thus, according to the substrate processing method according to the embodiment, a film for ensuring sufficient barrier properties for the barrier film (manganese oxide film 9) while suppressing evaporation of moisture in the interlayer insulating film 5. A substrate processing method capable of processing the substrate 1 at a low temperature can be obtained so that the thickness can be obtained.

(Device configuration)
Next, an example of a substrate processing apparatus capable of executing the substrate processing method according to the one embodiment will be described. In the substrate processing method according to the embodiment, for example, a cluster tool type (multi-chamber type) substrate processing system can be used.

  FIG. 5 is a plan view schematically showing an example of a substrate processing system capable of performing the substrate processing method according to one embodiment of the present invention.

  As shown in FIG. 5, the substrate processing system 100 includes a processing unit 110 that performs processing on the substrate 1, a loading / unloading unit 120 that loads / unloads the substrate W into / from the processing unit 110, and a control unit 130 that controls the system 100. It has.

  In this example, the processing unit 110 includes four processing containers for processing the substrate 1 (processing containers 111a to 111d). Each of these processing containers 111a and 111b is configured so that the inside thereof can be depressurized to a predetermined degree of vacuum. In the processing container 111a, Step 1 shown in FIG. 2, that is, a process of adsorbing an organic acid on the copper oxide 7 is performed. In the processing vessel 111b, step 2 shown in FIG. 2, that is, a step of adsorbing the manganese precursor on the interlayer insulating film 5 is performed. In the processing vessel 111c, step 3 shown in FIG. 2, that is, the step of heating the substrate 1 to sublimate the organic acid copper complex 8 and forming the manganese oxide film 9 on the surface of the second interlayer insulating film 5 is performed. Is done. In the processing vessel 111d, step 4 shown in FIG. 2, that is, the step of forming the copper or copper alloy film 10 on the wiring 3 and the interlayer insulating film 5 exposed at the bottom of the opening 6 is performed. The processing containers 111a to 111d are connected to one transfer chamber 112 through a gate valve G.

  The loading / unloading unit 120 includes a loading / unloading chamber 121. The carry-in / out chamber 121 is configured to be capable of adjusting the inside to atmospheric pressure or almost atmospheric pressure, for example, slightly positive pressure with respect to the outside atmospheric pressure. The plane shape of the loading / unloading chamber 121 is a rectangle having a long side and a short side when viewed from the plane. The long side of the rectangle is adjacent to the processing unit 110. The loading / unloading chamber 121 includes a load port to which a carrier C that accommodates the substrate 1 is attached. In this example, three load ports 122 a to 122 c are provided on the long side of the loading / unloading chamber 121 facing the processing unit 110. In this example, the number of load ports is three, but the number is not limited to these, and the number is arbitrary. Each of the load ports 122a to 122c is provided with a shutter (not shown). When a carrier C that accommodates the substrate 1 or is attached to these load ports 122a to 122c, the shutter (not shown) is released. The inside of the carrier C communicates with the inside of the loading / unloading chamber 121 while preventing the outside air from entering.

  Between the processing unit 110 and the loading / unloading unit 120, a load lock chamber, in this example, two load lock chambers 141a and 141b are provided. Each of the load lock chambers 141a and 141b is configured to be able to switch the inside to a predetermined degree of vacuum and atmospheric pressure or almost atmospheric pressure. The load lock chambers 141a and 141b are connected to the carry-in / out chamber 121 and the transfer chamber 112 through the gate valve G, respectively. The load lock chambers 141a and 141b communicate with the loading / unloading chamber 121 by opening the corresponding gate valve G, and are blocked from the loading / unloading chamber 121 by closing the corresponding gate valve G. Further, the corresponding gate valve G is opened to communicate with the transfer chamber 112, and the corresponding gate valve G is closed to be shut off from the transfer chamber 112.

  A carry-in / out mechanism 123 is provided inside the carry-in / out chamber 121. The loading / unloading mechanism 123 performs loading / unloading of the substrate 1 with respect to the carrier C and loading / unloading of the substrate 1 with respect to the load lock chambers 141a and 141b.

  The transfer chamber 112 is configured as a vacuum container, for example, a vacuum container. Inside the transfer chamber 112, a transfer mechanism 113 for transferring the substrate 1 to and from the processing containers 111a to 111d and the load lock chambers 141a and 141b is provided. Thus, the substrate 1 can be transported without being exposed to the atmosphere, that is, without being exposed to the atmosphere.

  The control unit 130 controls the system 100. The control unit 130 includes a process controller 131, a user interface 132, and a storage unit 133. The user interface 132 includes a keyboard on which the process manager performs command input operations for managing the system 100, a display for visualizing and displaying the operating status of the system 100, and the like. The storage unit 133 stores a recipe in which a control program for realizing the processing by the system 100 under the control of the controller 131, driving condition data, and the like are recorded. The recipe is called from the storage unit 133 by an instruction from the user interface 132 as necessary, and the system 100 is controlled by causing the controller 131 to execute the recipe. For example, a recipe stored in a computer-readable storage medium such as a CD-ROM, a hard disk, or a flash memory may be used, or may be transmitted from another device at any time via a dedicated line, for example. It is also possible to use it.

  Thus, the substrate processing method according to the embodiment includes, for example, a processing container 111a that performs a process of adsorbing an organic acid on the copper oxide 7, a processing container 111b that performs a process of adsorbing a manganese precursor on the interlayer insulating film 5, The substrate 1 is heated to sublimate the organic acid copper complex 8 and the process of forming the manganese oxide film 9 on the surface of the interlayer insulating film 5 is performed. On the wiring 3 exposed at the bottom of the opening 6 and the interlayer insulation The processing container 111d for performing the step of forming the copper or copper alloy film 10 on the film 5 and the processing containers 111a to 111d communicate with each other, and transport between the processing containers 111a to 111d without exposing the substrate 1 to the atmosphere. This can be performed by using a so-called cluster tool type (multi-chamber type) substrate processing system 100 including the chamber 112.

  In addition, as a processing container in the system 100, a step of adsorbing an organic acid to the copper oxide 7 (step 1), a step of adsorbing a manganese precursor to the interlayer insulating film 5 (step 2), and the substrate 1 are heated to be organic. It is not necessary to separate the step (step 3) of sublimating the acid copper complex 8 and forming the manganese oxide film 9 on the surface of the interlayer insulating film 5, and it may be performed in one processing container.

  Even if the processing container 111d for performing the step of forming the copper or copper alloy film 10 (step 4) is not provided as the system 100, three processing containers 111a to 111c, or steps 1 to 3 are provided as one. What is necessary is just to provide the processing container performed with a processing container.

  As mentioned above, although this invention was demonstrated according to one Embodiment, this invention is not limited to one Embodiment, It can change variously in the range which does not deviate from the main point.

  For example, in the above embodiment, formic acid (HCOOH) gas is used as an example of an organic acid gas that adsorbs an organic acid to the copper oxide 7 to form the organic acid copper complex 8. It is not limited to formic acid gas. For example, the following organic acid gas can be used as the organic acid gas.

For example, as an organic acid,
Carboxylic acid having a carboxyl group (—COOH) As an example of the carboxylic acid,
Carboxylic acid R ¹ —COOH described by the following general formula (1) (1)
(R ¹ is hydrogen, or a linear or branched C ₁ -C ₂₀ alkyl or alkenyl group, preferably methyl, ethyl, propyl, butyl, pentyl or hexyl)
For example, acetic acid (CH ₃ COOH)
Propionic acid (CH ₃ CH ₂ COOH)
Butyric acid (CH ₃ (CH ₂ ) ₂ COOH)
Valeric acid (CH ₃ (CH ₂ ) ₃ COOH)
And so on.

Further, in the above-described embodiment, (EtCp) ₂ Mn is used as the manganese precursor. However, the present invention is not limited to this, and other cyclopenta manganese precursors can also be used.

Examples of cyclopenta manganese precursors include:
_{Cp 2 Mn [= Mn (C} 5 H 5) 2]
(MeCp) ₂ Mn [= Mn (CH ₃ C ₅ H ₄ ) ₂ ]
_{(I-PrCp) 2 Mn [} = Mn (C 3 H 7 C 5 H 4) 2]
MeCpMn (CO) ₃ [= (CH ₃ C ₅ H ₄ ) Mn (CO) ₃ ]
_{(T-BuCp) 2 Mn [} = Mn (C 4 H 9 C 5 H 4) 2]
_{Mn (DMPD) (EtCp) [} = Mn (C 7 H 11 C 2 H 5 C 5 H 4)]
((CH ₃ ) ₅ Cp) ₂ Mn [= Mn ((CH ₃ ) ₅ C ₅ H ₄ ) ₂ ]
Etc.

  Further, manganese precursors other than cyclopenta-based ones may be used.

As such a manganese precursor, for example,
Mn (acac) ₂ [= Mn (C ₅ H ₇ O ₂ ) ₂ ]
Mn (acac) ₃ [= Mn (C ₅ H ₇ O ₂ ) ₃ ]
Mn (hfac) ₂ [= Mn (C ₅ HF ₆ O ₂ ) ₃ ]
Etc.

  In the above-described embodiment, the TEOS film is used as the interlayer insulating film. However, the TEOS film is not limited to the TEOS film, and any insulating material including moisture may be used.

Further, the film is not limited to moisture, and may be a film containing OH groups. In particular, the film containing an OH group is preferably a film in which the OH group changes to moisture (H ₂ O) when reacted. This is because the metal raw material gas can be brought into contact with the moisture that has come out on the surface by taking out the moisture generated by changing the OH group.

For example, the barrier film may be formed using a cyclopenta metal-containing precursor other than manganese.
Further, another metal film may be formed as a seed layer or an adhesion layer between the barrier film formation and the copper film formation.
Furthermore, the formation of the copper or copper alloy film is not limited to the CVD method, and PVD or plating may be used.
In addition, the present invention can be variously modified without departing from the gist thereof.

  DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... 1st layer interlayer insulation film, 3 ... Wiring using copper, 4 ... Barrier film, 5 ... 2nd layer interlayer insulation film, 6 ... Opening, 7 ... Copper oxide, 8 ... Organic Acid copper complex, 9 ... manganese oxide film, 10 ... copper or copper alloy film.

Claims (9)

Wiring using copper,
An interlayer insulating film formed on the wiring, having an opening reaching the wiring, and containing moisture or an OH group,
A substrate processing method for processing a substrate in which copper oxide is formed on a surface of the wiring exposed at the bottom of the opening,
(1) forming an organic acid copper complex by adsorbing an organic acid to the copper oxide;
(2) After the step (1), a step of adsorbing a manganese precursor on the interlayer insulating film;
(3) heating the substrate, sublimating the organic acid copper complex, and forming a manganese oxide film on the surface of the interlayer insulating film;
The substrate processing method characterized by comprising. After the step (3),
(4) The substrate processing method according to claim 1, further comprising a step of forming a copper or copper alloy film on the wiring and the interlayer insulating film exposed to the bottom of the opening. .   3. The substrate processing method according to claim 1, wherein the steps (1) to (3) are performed in the same chamber.   3. The substrate processing method according to claim 1, wherein the steps (1) to (3) are performed in another chamber without exposing the substrate to the atmosphere.   The substrate processing method according to claim 2, wherein the steps (1) to (4) are performed in another chamber without exposing the substrate to the atmosphere. Steps (1) to (3) are performed in the same chamber,
The substrate processing method according to claim 2, wherein the step (4) is performed in another chamber without exposing the substrate to the atmosphere. The step (1) is performed at a first temperature,
The step (2) is performed at a second temperature equal to or higher than the first temperature,
The substrate processing method according to claim 1, wherein the step (3) is performed at a third temperature equal to or higher than the second temperature. A wiring using copper, and an interlayer insulating film formed on the wiring and having an opening reaching the wiring and containing moisture or an OH group, and exposed to a bottom of the opening A processing unit including at least one processing container for storing a substrate in which copper oxide is formed on the surface of the wiring;
A control unit that controls the processing unit to execute the substrate processing method according to any one of claims 1 to 7, with respect to the substrate accommodated in the at least one processing container;
A substrate processing apparatus comprising: A computer-readable storage medium that operates on a computer and stores a control program for controlling the substrate processing apparatus,
A computer-readable storage medium characterized in that, when executed, the control program controls the substrate processing apparatus so that the substrate processing method according to any one of claims 1 to 7 is performed.

Images