JP2010077504A - Film deposition method and film-depositing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film deposition method capable of depositing a metallic film having the uniform film thickness even when the metallic film is deposited by using metal carbonyl for a raw material. <P>SOLUTION: In the film deposition method for depositing a film of a metal A on a substrate W to be processed by using a compound AxBy of the metal A for generating the reversible reaction and a functional group B for a raw material, gas 31 containing the compound AxBy is fed to a surface of the substrate W, the compound AxBy is decomposed into the metal A and the functional group B in a vicinity of the surface of the substrate W, inert gas 41 is fed to a vicinity of an outer peripheral part of the substrate W so that the film deposition rate at a center part of the substrate W is balanced with the film deposition rate of the outer peripheral part of the substrate W. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a film forming method and a film forming apparatus for forming a film on a substrate to be processed such as a semiconductor substrate.

  In manufacturing a semiconductor device, a film such as an insulating film or a conductive film is formed on a semiconductor wafer. The insulating film is generally formed using a chemical vapor deposition method (CVD method), and the conductor film is generally formed using a sputtering method.

  As semiconductor devices are miniaturized, it has become important to form a film having good step coverage. For this reason, the CVD method is frequently used also in the formation of a conductor film.

As a method for forming a conductor film using a CVD method, a method for forming a metal film using metal carbonyl as a raw material is known (Patent Document 1).
JP 2004-197163 A

  In forming a metal film using metal carbonyl as a raw material, CO gas is used as a carrier gas in order to stably supply metal carbonyl. Metal carbonyl is a precursor of a metal film, and is divided into metal and CO gas during decomposition, for example, thermal decomposition.

  However, it has recently been found that CO gas has a function of suppressing the decomposition reaction of metal carbonyl. For this reason, the film formation using metal carbonyl as a raw material has a tendency that the film formation rate is high in the central portion of the substrate to be processed and becomes slower toward the outer peripheral portion.

  From such a tendency, in the formation of a metal film using metal carbonyl as a raw material, how to form a metal film having a uniform film thickness from the central part to the outer peripheral part of the substrate to be processed becomes an issue. Yes.

  The present invention relates to a film forming method capable of forming a metal film having a uniform film thickness even when a metal film is formed using metal carbonyl as a raw material, and film formation using the film forming method An object is to provide an apparatus.

  In order to achieve the above object, a film forming method according to a first aspect of the present invention uses a compound AxBy of a metal A and a functional group B that causes a reversible reaction as a raw material, and the metal A film is processed. A film forming method for forming a film on a substrate, wherein a gas containing the compound AxBy is supplied to the surface of the substrate to be processed, and the compound AxBy is converted into a metal A and a functional group B in the vicinity of the surface of the substrate to be processed. While decomposing, supplying an inert gas to the vicinity of the outer peripheral portion of the substrate to be processed so that the film forming speed of the central portion of the substrate to be processed and the film forming speed of the outer peripheral portion of the substrate to be processed are balanced. The metal A film is formed on the substrate to be processed.

  Moreover, the film forming apparatus according to the second aspect of the present invention forms the metal A film on the substrate to be processed using a compound AxBy of the metal A and the functional group B that causes a reversible reaction as a raw material. A film forming apparatus, wherein a mounting table on which the substrate to be processed is mounted is disposed, a processing chamber for performing a film forming process on a surface of the substrate to be processed, and a gas containing the compound AxBy. A source gas supply unit for supplying to the surface of the substrate, an inert gas supply unit for supplying an inert gas to the vicinity of the outer peripheral portion of the substrate to be processed, and a flow rate of the inert gas during the film formation process. And a control mechanism for controlling the film formation speed at the central portion of the processing substrate to be balanced with the film formation speed at the outer peripheral portion of the substrate to be processed.

  According to this invention, even when a metal film is formed using metal carbonyl as a raw material, a film forming method capable of forming a metal film having a uniform film thickness and the film forming method are used. A film forming apparatus can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. In this description, common parts are denoted by common reference symbols throughout the drawings.

(First embodiment)
FIG. 1 is a sectional view schematically showing an example of a film forming apparatus according to the first embodiment of the present invention.

  As shown in FIG. 1, in the film forming apparatus according to the first embodiment, a mounting table 2 on which a substrate W to be processed is mounted is disposed, and a processing chamber that performs a film forming process on the surface of the substrate W to be processed. 1 is provided.

  A source gas supply unit 3 is provided in the upper part of the processing chamber 1. The source gas supply unit 3 is connected to a gas supply mechanism 5. The gas supply mechanism 5 supplies a gas 31 containing a film raw material to be formed to the raw material gas supply unit 3 through a gas supply pipe 51a. In this example, the source gas supply unit 3 is a shower head, and is connected to the gas supply pipe 51a. The diffusion space 32 in which the gas 31 containing the source is diffused and the surface of the diffusion space 32 that faces the substrate W to be processed. And a plurality of gas discharge holes 33 formed on the surface.

  The gas supply mechanism 5 includes a source gas supply unit 52, a carrier gas supply unit 53, and an inert gas supply unit 54.

In this example, a compound AxBy of a metal A and a functional group B that causes a reversible reaction “AxBy⇔xA + yB” is used as a raw material of a film to be formed. An example of such a compound is metal carbonyl in which a carbonyl group is combined as a functional group with metal A. In this example, a ruthenium-carbonyl compound in which a carbonyl group is combined with ruthenium (Ru) is used as the metal carbonyl, and Ru ₃ (CO) ₁₂ is used as a specific molecular formula. Ru ₃ (CO) ₁₂ is solid at room temperature. For this reason, the raw material gas supply unit 52 of this example has a heating mechanism and includes a bubbler 55 that supplies the sublimated Ru ₃ (CO) ₁₂ together with the carrier gas.

In this example, CO gas is used as the carrier gas. The CO gas is sent from the carrier gas supply source 56 to the gas supply pipe 51a through the mass flow controller (MFC) 57a and the valve 58a. At the same time, in this example, CO gas is supplied as bubbling gas to Ru ₃ (CO) ₁₂ held in the bubbler 55 via the MFC 57b and the valve 58b. By supplying CO gas as a bubbling gas, Ru ₃ (CO) ₁₂ is vaporized. The vaporized Ru ₃ (CO) ₁₂ is sent to the gas supply pipe 51a through the valve 58c.

  Furthermore, in this example, argon (Ar) gas is used as an inert gas for diluting the gas 31 containing the raw material. Ar gas is sent from the inert gas supply source 59 to the gas supply pipe 51 through the mass flow controller (MFC) 57c and the valve 58d.

Thus, inside the gas supply pipe 51a, the carrier gas (CO gas in this example), the raw material gas (Ru ₃ (CO) ₁₂ gas in this example), and the inert gas (Ar gas in this example) are contained. A gas 31 containing raw materials mixed at an appropriate flow rate is generated.

  An inert gas supply unit 4 is provided on the outer peripheral portion of the mounting table 2. The inert gas supply unit 4 is connected to a gas supply mechanism 5. The gas supply mechanism 5 supplies the inert gas 41 from the inert gas supply source 59 to the gas supply pipe 51b through the MFC 57d and the valve 58e. The inert gas 41 supplied to the gas supply pipe 51b is supplied to the inert gas supply unit 4, and is further supplied from the periphery of the outer peripheral edge of the substrate to be processed W to the vicinity of the outer peripheral portion of the substrate to be processed W. The

A heating mechanism 22 connected to a heater power source 21 is provided in the mounting table 2. The mounting table 2 also serves as a heater plate for heating the substrate W to be processed. The gas 31 containing the raw material is decomposed in the vicinity of the surface of the heated substrate W to be processed. In this example, among the gas 31 containing the raw material, Ru ₃ (CO) ₁₂ gas, which is the raw material gas, is thermally decomposed into Ru and CO gas as follows, and Ru is converted into a metal solid and the surface of the substrate W to be processed. Deposited on top.

Ru ₃ (CO) ₁₂ ↑ ⇔ Ru ₃ (CO) _12−x ↑ + XCO ↑
Ru ₃ (CO) _12−x ↑ + Q → 3Ru + (12−X) CO ↑
Here, “⇔” indicates reversible, “↑” indicates a gas state, those without “↑” indicate a solid state, and “Q” indicates an amount of heat. It shows that.

As is clear from the above chemical formula, when focusing on the first chemical formula, CO gas is reversibly generated by thermal decomposition, and therefore, when the CO gas concentration increases, the reaction proceeds to the left. Will be promoted and the reaction to the right will be suppressed. As a result, since the decomposition of Ru ₃ (CO) ₁₂ that is the source gas is suppressed, a uniform film is formed over the entire surface of the substrate W to be processed by adjusting the partial pressure (or concentration) of the CO gas as will be described later. A metal film having a thickness can be formed.

  An exhaust device 6 is connected to the processing chamber 1. For example, the exhaust device 6 exhausts the processing space S in the processing chamber 1 during processing so that the pressure of the processing space S is maintained at an appropriate pressure.

  The control mechanism 7 includes a process controller 71 composed of a microprocessor (computer), a keyboard that allows an operator to input commands to manage the film forming apparatus, and a display that visualizes and displays the operating status of the substrate processing system. And the like, and a control program for realizing various processes executed by the film forming apparatus under the control of the process controller 71, various data, and causing the film forming apparatus to execute processes according to processing conditions. And a storage unit 73 in which a recipe is stored.

  The recipe is stored in a storage medium in the storage unit 73. The storage medium may be a hard disk or a portable medium such as a CD-ROM, DVD, or flash memory. Moreover, you may make it transmit a recipe suitably from another apparatus via a dedicated line, for example. If necessary, an arbitrary recipe is called from the storage unit 73 by an instruction from the user interface 72 and is executed by the process controller 71, so that a desired process in the film forming apparatus is performed under the control of the process controller 71. Is done.

  The film forming method performed by the film forming apparatus according to the first embodiment basically uses a compound AxBy of a metal A and a functional group B that causes a reversible reaction “AxBy⇔xA + yB” as a raw material. Is formed on the substrate to be processed. Then, the compound AxBy, that is, the gas 31 containing the raw material is supplied to the surface of the substrate W to be processed, and the compound AxBy is decomposed into the metal A and the functional group B in the vicinity of the surface of the substrate W to be processed. A metal A film is deposited on the surface of W.

  The functional group B is a carbonyl group in this example, and the compound AxBy is a metal carbonyl. Metal carbonyl is a precursor of a film (metal) to be formed, and is divided into a metal and CO gas during decomposition, for example, thermal decomposition.

  As described above, when the CO gas concentration is high, it has a function of suppressing the decomposition reaction of metal carbonyl. Therefore, in the film formation using metal carbonyl as a raw material, the film formation rate is high in the central portion of the substrate to be processed. It shows a tendency to slow down toward the part.

  In the first embodiment, by using such a tendency, the inert gas 41 is supplied to the vicinity of the outer peripheral portion of the substrate to be processed W, the film formation speed of the central portion of the substrate to be processed W, the substrate W to be processed, and the like. The film forming speed of the outer peripheral portion of the film is balanced. An example for balancing is the functional group B in the atmosphere near the outer peripheral portion of the substrate W to be processed, which is CO gas in this example. It is equal to or lower than the partial pressure.

  By adjusting the partial pressure of the CO gas in this way, it becomes possible to balance the film formation rate of the central portion of the substrate W to be processed and the film formation rate of the outer peripheral portion of the substrate W to be processed. Even if the metal film used for the raw material is formed, it is possible to form a metal film having a uniform film thickness from the central portion to the outer peripheral portion of the substrate W to be processed.

  FIG. 2 is a diagram showing the film thickness ratio (ratio of the film thickness at the corresponding position / the film thickness of the center) of the film formed on the substrate to be processed. The dotted line in FIG. 2 is an example in which the partial pressure of CO gas is not adjusted (inert gas is not supplied), and the solid line is an example in which the partial pressure of CO gas is adjusted (inert gas in the vicinity of the outer peripheral portion of the wafer). Supply).

The deposition conditions were a temperature of 215 ° C., a pressure of 100 mT, a CO gas of 100 sccm as a carrier gas, a deposition time of 60 sec, a Ru ₃ (CO) ₁₂ gas as a source gas, and a Ru film was deposited on the wafer. Ar gas was used as the inert gas.

  As shown in FIG. 2, when the partial pressure of the CO gas is not adjusted (inert gas: 0 sccm), the film thickness is closer to the outer peripheral part of the wafer than the film thickness near the central part (center) of the wafer. It turns out that there is a tendency to become thin.

  On the other hand, when the partial pressure of CO gas is adjusted (inert gas: 98 sccm), the film thickness at the outer peripheral portion of the wafer tends to be thicker than when the partial pressure of CO gas is not adjusted. It was. Adjusting the partial pressure of CO gas by supplying an inert gas in the vicinity of the outer peripheral portion of the wafer means that the concentration of CO gas in the atmosphere is locally reduced in the vicinity of the outer peripheral portion of the wafer. is there.

  In this way, by locally reducing the concentration of CO gas in the atmosphere in the vicinity of the outer peripheral portion of the wafer, deposition of a metal film, in this example, a ruthenium film, on the outer peripheral portion of the wafer can be promoted.

  Therefore, if the concentration of CO gas in the atmosphere in the vicinity of the outer peripheral portion of the wafer is decreased so that the film forming speed at the central portion of the wafer and the film forming speed at the outer peripheral portion of the wafer are balanced, A ruthenium film having a uniform film thickness can be formed from the portion to the outer peripheral portion.

  Such adjustment of the concentration of CO gas in the atmosphere in the vicinity of the outer peripheral portion of the wafer can be realized, for example, by adjusting the flow rate of the inert gas in the MFC 57d using the control mechanism 7.

  As described above, according to the first embodiment, even when a metal film is formed using metal carbonyl as a raw material, a film forming method capable of forming a metal film having a uniform film thickness, and its formation. A film forming apparatus using the film method can be provided.

(Second Embodiment)
The second embodiment is a specific example of the inert gas supply unit 4.

  3A is a sectional view showing a first specific example of the inert gas supply unit 4, and FIG. 3B is an enlarged view of FIG. 3A.

  As shown in FIG. 3A, an outer peripheral member 23 that surrounds the outer edge of the mounting table 2 is provided outside the mounting table 2 that also serves as a heater plate. The outer peripheral member 23 is provided with a pin member 24 that moves vertically through the outer peripheral member 23, and a ring-shaped cover ring 25 that covers a space between the substrate to be processed W and the outer peripheral member 23 at the tip of the pin member 24. Is provided.

  The inert gas supply unit 4 can be obtained by using, for example, a clearance 26 generated between the mounting table 2 and the outer peripheral member 23. If an inert gas 41 is allowed to flow through the clearance 26, a part of the inert gas 41 also flows outside the cover ring 25 as indicated by an arrow A, but the remaining part of the outer periphery of the substrate W to be processed is indicated by an arrow B. Then, it can flow upward in the vicinity of the outer peripheral portion of the substrate W to be processed.

  As described above, the inert gas supply unit 4 can be easily obtained by using the clearance 26 generated between the mounting table 2 and the outer peripheral member 23, for example.

  4A is a cross-sectional view showing a second specific example of the inert gas supply unit 4, and FIG. 4B is an enlarged view of FIG. 4A.

  In the first example shown in FIGS. 3A and 3B, the cover ring 25 covers the space between the substrate W to be processed and the outer peripheral member 23.

  In the second example, the cover ring 25 is used to further cover the outer peripheral portion of the substrate W to be processed.

  When the outer peripheral portion of the substrate W to be processed is covered using the cover ring 25, film deposition on the covered portion is suppressed, and the substrate W to be processed without film formation on the so-called bevel portion can be obtained.

  The user may arbitrarily select whether or not to attach the deposited film to the bevel portion of the substrate W to be processed.

  Even when the cover ring 25 is used to cover the outer peripheral portion of the substrate W to be processed, there is a clearance 27 between the cover ring 25 and the substrate to be processed. The inert gas 41 can flow from the outer peripheral portion of the substrate to be processed W through the clearance 27 to the vicinity of the outer peripheral portion of the substrate to be processed W.

  Therefore, even when the outer peripheral portion of the substrate W to be processed is covered using the cover ring 25, the inert supply unit 4 includes, for example, the clearance 26 generated between the mounting table 2 and the outer peripheral member 23, and the cover ring 25. Can be easily obtained by using the clearance 27 generated between the substrate and the substrate to be processed.

(Third embodiment)
FIG. 5 is a sectional view schematically showing an example of a film forming apparatus according to the third embodiment of the present invention.

  As shown in FIG. 5, the film forming apparatus according to the third embodiment is different from the film forming apparatus according to the first embodiment in that the inert gas supply unit 4 is not an outer peripheral part of the mounting table 2. This is provided at the outer peripheral portion of the source gas supply unit 3. Other than this, since it is the film forming apparatus according to the first embodiment, the same parts are denoted by the same reference numerals, and the description thereof is omitted.

  As described above, the inert gas supply unit 4 is provided in the outer peripheral portion of the source gas supply unit 3, and the inert gas 41 is supplied from the periphery of the source gas supply unit 3 to above the vicinity of the outer peripheral portion of the substrate W to be processed. Even in such a case, for example, the partial pressure of the functional group B in the atmosphere in the vicinity of the outer peripheral portion of the substrate W to be processed, for example, the CO gas partial pressure is made equal to or lower than the partial pressure in the vicinity of the central portion of the substrate W Thus, the film formation rate at the central portion of the substrate W to be processed and the film formation rate at the outer peripheral portion of the substrate W to be processed can be balanced.

  Therefore, the same effect as the first embodiment can be obtained.

  As mentioned above, although this invention was demonstrated based on some embodiment, this invention is not limited to the said embodiment.

For example, in the above-described embodiment, a ruthenium-carbonyl compound such as Ru ₃ (CO) ₁₂ is used as a raw material for a film to be formed, and the Ru film is formed as an example. The present invention is not limited to this film formation, and can also be applied to the formation of a metal film using a metal carbonyl other than a ruthenium-carbonyl compound as a raw material.

Specific examples include, for example, Cr (CO) ₆ , Co ₂ (CO) ₈ , Ni (CO) ₄ , Mo (CO) ₆ , Rh ₄ (CO) ₁₂ , W (CO) ₆ , and Re _2. Chromium (Cr) film, cobalt (Co) film, nickel (Ni) film, molybdenum (Mo) film, rhodium (Rh) film, tungsten (W) film, and rhenium (Re) using (CO) ₁₀ as a raw material It can also be applied to film formation.

  In addition, although argon gas is used as the inert gas, the inert gas is not limited to argon gas, and nitrogen gas or a rare gas other than argon can also be used.

  In addition, the present invention can be variously modified without departing from the gist of the invention, and can be implemented by combining the above-described embodiments. In particular, in the example of the inert gas supply unit 4 described in the second embodiment, the first example and the second example are combined, and the inert gas supply unit 4 is connected to the outer peripheral portion of the mounting table 2; It is also possible to provide both on the outer peripheral portion of the source gas supply unit 3.

Sectional drawing which shows roughly an example of the film-forming apparatus which concerns on 2nd Embodiment of this invention The figure which shows the relationship between the film thickness in the applicable position of the substrate to be processed and the film thickness of the center 3A is a cross-sectional view showing a first specific example of the inert gas supply unit 4, and FIG. 3B is an enlarged view of FIG. 3A. 4A is a cross-sectional view showing a second specific example of the inert gas supply unit 4, and FIG. 4B is an enlarged view of FIG. 4A. Sectional drawing which shows roughly an example of the film-forming apparatus which concerns on 3rd Embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Processing chamber, 2 ... Mounting stand, 3 ... Raw material gas supply part, 4 ... Inert gas supply part, 5 ... Gas supply mechanism, 6 ... Exhaust device, 7 ... Control mechanism

Claims (14)

A film forming method for forming a film of the metal A on a substrate to be processed using a compound AxBy of a metal A and a functional group B that causes a reversible reaction as a raw material,
Supplying a gas containing the compound AxBy to the surface of the substrate to be processed, decomposing the compound AxBy into a metal A and a functional group B in the vicinity of the surface of the substrate to be processed;
An inert gas is supplied to the vicinity of the outer peripheral portion of the substrate to be processed so that the film forming speed of the central portion of the substrate to be processed and the film forming speed of the outer peripheral portion of the substrate to be processed are balanced. A film forming method comprising forming a film on the substrate to be processed.   The partial pressure of the functional group B in the atmosphere near the outer peripheral portion of the substrate to be processed is equal to or lower than the partial pressure of the functional group B near the center portion of the substrate to be processed. Item 2. The film forming method according to Item 1.   3. The film forming method according to claim 1, wherein the inert gas is supplied from the periphery of the outer peripheral edge of the substrate to be processed upward to the vicinity of the outer peripheral portion of the substrate to be processed.   The said inert gas is supplied to the upper direction of the outer peripheral part vicinity of the said to-be-processed substrate from the circumference | surroundings of the gas supply part which supplies the gas containing the said compound AxBy. The film forming method.   The film forming method according to any one of claims 1 to 4, wherein the functional group B is a carbonyl group.   The film forming method according to claim 5, wherein the metal includes any one of chromium, cobalt, nickel, molybdenum, ruthenium, rhodium, tungsten, and rhenium.   The film forming method according to claim 5 or 6, wherein the gas containing the compound AxBy includes the compound AxBy gas and a CO gas as a carrier gas. A film forming apparatus for forming a film of the metal A on a substrate to be processed using a compound AxBy of a metal A and a functional group B that causes a reversible reaction as a raw material,
A processing chamber in which a mounting table on which the substrate to be processed is mounted is disposed, and a film forming process is performed on the surface of the substrate to be processed;
A source gas supply unit for supplying a gas containing the compound AxBy to the surface of the substrate to be processed;
An inert gas supply unit for supplying an inert gas in the vicinity of the outer peripheral portion of the substrate to be processed;
A control mechanism for controlling the flow rate of the inert gas during the film forming process so that the film forming speed of the central portion of the substrate to be processed and the film forming speed of the outer peripheral portion of the substrate to be processed are balanced;
A film forming apparatus comprising:   The partial pressure of the functional group B in the atmosphere near the outer peripheral portion of the substrate to be processed is equal to or lower than the partial pressure of the functional group B near the center portion of the substrate to be processed. Item 9. The film forming apparatus according to Item 8.   The film forming apparatus according to claim 8, wherein the inert gas supply unit is provided in an outer peripheral portion of the mounting table.   The film forming apparatus according to claim 8, wherein the inert gas supply unit is provided on an outer peripheral portion of the source gas supply unit.   The film forming apparatus according to claim 8, wherein the functional group B is a carbonyl group.   The film forming apparatus according to claim 12, wherein the metal includes any one of chromium, cobalt, nickel, molybdenum, ruthenium, rhodium, tungsten, and rhenium.   The film forming apparatus according to claim 12 or 13, wherein the gas containing the compound AxBy includes the compound AxBy gas and a CO gas as a carrier gas.

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