Substrate processing method and substrate processing device

Abstract

To suppress the surface corrosion of a conductive layer or a semiconductor layer.SOLUTION: There is provided a substrate processing method including the steps of: preparing a substrate having a conductive layer or a semiconductor layer in a processing container; supplying a first gas containing hydrogen and nitrogen to the processing container and exposing the substrate to a plasma generated from the first gas, thereby reducing the surface of the conductive layer or the semiconductor layer; and supplying a second gas containing hydrogenated silicon or alkylated aluminum and exposing the reduced conductive layer or semiconductor layer to the second gas, thereby causing silicon or aluminum to be adsorbed onto the conductive layer or semiconductor layer and forming a stabilization layer.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a substrate processing method and a substrate processing apparatus.

Background Art

[0002] Patent Document 1 describes forming an insulating film on a conductive layer formed on a semiconductor substrate, dry-etching the insulating film using a first gas containing a halogen gas to expose the surface of the conductive layer, performing a first plasma treatment on the exposed conductive layer using a second gas reducible with respect to the exposed conductive layer, and performing a second plasma treatment on the exposed conductive layer using a third gas containing C element and O element and not containing a halogen element. Further, it is described that as the second gas, a gas containing H2, N2, NH4, for example, N2 / H2 is used for plasma treatment.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a substrate processing method and a substrate processing apparatus capable of suppressing the corrosion of the surface of a conductive layer or a semiconductor layer.

Means for Solving the Problems

[0005] According to one aspect of the present disclosure, there is provided a substrate processing method including: preparing a substrate having a conductive layer or a semiconductor layer in a processing container; supplying a first gas containing hydrogen and nitrogen into the processing container, and exposing the substrate to plasma generated from the first gas to reduce the surface of the conductive layer or the semiconductor layer; and supplying a second gas containing hydrogenated silicon or alkylated aluminum, and exposing the reduced conductive layer or semiconductor layer to the second gas to adsorb silicon or aluminum onto the conductive layer or the semiconductor layer to form a stabilization layer.

Advantages of the Invention

[0006] According to one aspect, corrosion of the surface of the conductive layer or the semiconductor layer can be suppressed.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments for implementing the present disclosure will be described with reference to the drawings. In each drawing, the same reference numerals are assigned to the same components, and redundant descriptions may be omitted.

[0009] [Conventional Example of Substrate Processing Method] When performing etching of a metal film (conductive layer) or selective film formation using SiF4 gas or the like, halogenation or oxidation of the metal film occurs by using an etchant or precursor containing a halogen compound. For example, in the halogenation of a metal film, adsorption of a halogen compound occurs on the surface of the metal film. When the halogenated or oxidized metal film is exposed to the atmosphere, corrosion occurs due to the reaction of the surface of the metal film with water, which may adversely affect the formation of a metal pattern or damage the device. Therefore, a substrate processing method for suppressing corrosion becomes important.

[0010] An example of a substrate processing method that has been conventionally performed as a general measure against corrosion will be described with reference to FIG. 1. In FIG. 1, a film formation process is executed in step S1. For example, when forming an insulating film on an underlying layer on which a metal film pattern is formed using SiF4 gas, halogenation of the metal film occurs due to fluorine contained in the SiF4 gas.

[0011] In step S2, plasma is generated from H2 gas for the purpose of removing excess halogen, and the halogenated metal film is exposed to the plasma for treatment. Then, in step S3, water is supplied to the surface of the wafer, and the surface of the wafer is washed with water. By this water washing, excess halogen can be removed.

[0012] However, in this method, since it is necessary to manage the time (referred to as Q-Time) during which the wafer is exposed to the atmosphere for water washing, the process becomes complicated. Therefore, a process capable of suppressing corrosion without exposing the wafer to the atmosphere instead of water washing, or a process for extending Q-Time, becomes important.

[0013] Therefore, in the substrate processing method according to the present embodiment, the surface corrosion of the conductive layer or the semiconductor layer is suppressed by surface treatment of the conductive layer or the semiconductor layer. Hereinafter, with reference to FIG. 2, a configuration example of a substrate processing apparatus according to an embodiment capable of executing the substrate processing method according to an embodiment will be described. Thereafter, with reference to FIG. 3, an example of the substrate processing method according to an embodiment will be described.

[0014] [Substrate Processing Apparatus] FIG. 2 is a diagram showing an example of a plasma processing apparatus. FIG. 2 schematically shows a cross-sectional structure of a plasma processing apparatus 10 that can be used in various embodiments of a substrate processing method for a substrate exemplified by a wafer W. As shown in FIG. 2, the plasma processing apparatus 10 is an inductively coupled plasma processing apparatus. The plasma processing apparatus 10 is an example of a substrate processing apparatus. The substrate processing apparatus is not limited to an inductively coupled plasma processing apparatus, and plasma processing apparatuses such as a capacitively coupled plasma processing apparatus and a microwave plasma processing apparatus can be applied. The insulating film formed on the wafer W is a film containing at least silicon (Si) and oxygen (O), and may be, for example, a SiO x film or a SiOF film.

[0015] The plasma processing apparatus 10 includes a processing container 1. The processing container 1 is provided airtightly. The processing container 1 contains a conductive material. For example, the inner wall surface of the processing container 1 may contain a material such as anodized aluminum. The processing container 1 is assembled disassemblably and is grounded by a ground wire 1a. The processing container 1 is partitioned into an antenna chamber 3 and a processing chamber 4 vertically by a dielectric wall 2. The dielectric wall 2 constitutes the ceiling wall of the processing chamber 4. The dielectric wall 2 is made of, for example, ceramics such as Al2O3, quartz, or the like.

[0016] A shower housing 11 for supplying a processing gas is fitted into the lower portion of the dielectric wall 2. The shower housing 11 is provided in a cross shape and supports the dielectric wall 2 from below. The shower housing 11 that supports the dielectric wall 2 is suspended from the ceiling of the processing container 1 by a plurality of suspenders (not shown).

[0017] The shower housing 11 may contain a conductive material such as metal. The inner surface of the shower housing 11 may contain, for example, anodized aluminum or the like so that contaminants do not occur. A gas flow path 12 extending along the dielectric wall 2 is formed in the shower housing 11, and a plurality of gas supply holes 12a extending toward the mounting table 22 communicate with the gas flow path 12. A gas supply pipe 20a is provided at the center of the upper surface of the dielectric wall 2 so as to communicate with the gas flow path 12. The gas supply pipe 20a extends outside the processing container 1 from the dielectric wall 2 and is connected to a processing gas supply system 20 including a processing gas supply source and a valve system or the like. The processing gas supply source has a SiF4 gas supply source 51a, an O2 gas supply source 52a, a H2 gas supply source 53a, a N2 gas supply source 54a, a SiH4 gas supply source 55a, and an Ar gas supply source 56a.

[0018] The SiF4 gas supply source 51a supplies SiF4 gas into the processing chamber 4 through the gas supply line 51b. A flow controller 51c and a valve 51d are interposed in the gas supply line 51b from the upstream side. The downstream side of the valve 51d in the gas supply line 51b is connected to the gas supply pipe 20a through the gas supply line 57. The supply and stop of the SiF4 gas supplied from the SiF4 gas supply source 51a are performed by opening and closing the valve 51d.

[0019] The O2 gas supply source 52a supplies O2 gas into the processing chamber 4 through the gas supply line 52b. A flow controller 52c and a valve 52d are interposed in the gas supply line 52b from the upstream side. The downstream side of the valve 52d in the gas supply line 52b is connected to the gas supply pipe 20a through the gas supply line 57. The supply and stop of the O2 gas supplied from the O2 gas supply source 52a are performed by opening and closing the valve 52d.

[0020] The H2 gas supply source 53a supplies H2 gas into the processing chamber 4 via the gas supply line 53b. A flow controller 53c and a valve 53d are provided in the gas supply line 53b in the upstream side. The downstream side of the valve 53d in the gas supply line 53b is connected to the gas supply pipe 20a via the gas supply line 57. The supply and stop of the H2 gas supplied from the H2 gas supply source 53a are performed by opening and closing the valve 53d.

[0021] The N2 gas supply source 54a supplies N2 gas into the processing chamber 4 via the gas supply line 54b. A flow controller 54c and a valve 54d are provided in the gas supply line 54b in the upstream side. The downstream side of the valve 54d in the gas supply line 54b is connected to the gas supply pipe 20a via the gas supply line 57. The supply and stop of the N2 gas supplied from the N2 gas supply source 54a are performed by opening and closing the valve 54d.

[0022] The SiH4 gas supply source 55a supplies SiH4 gas into the processing chamber 4 via the gas supply line 55b. A flow controller 55c and a valve 55d are provided in the gas supply line 55b in the upstream side. The downstream side of the valve 55d in the gas supply line 55b is connected to the gas supply pipe 20a via the gas supply line 57. The supply and stop of the SiH4 gas supplied from the SiH4 gas supply source 55a are performed by opening and closing the valve 55d.

[0023] The Ar gas supply source 56a supplies Ar gas into the processing chamber 4 via the gas supply line 56b. A flow controller 56c and a valve 56d are provided in the gas supply line 56b in the upstream side. The downstream side of the valve 56d in the gas supply line 56b is connected to the gas supply pipe 20a via the gas supply line 57. The supply and stop of the Ar gas supplied from the Ar gas supply source 56a are performed by opening and closing the valve 56d.

[0024] In plasma processing, the processing gas supplied from the processing gas supply system 20 is supplied into the shower housing 11 through the gas supply pipe 20a, and is discharged into the processing chamber 4 from the gas supply holes 12a on the lower surface of the shower housing 11 (the surface facing the processing chamber 4).

[0025] A support shelf 5 protruding inward is provided between the side wall 3a of the antenna chamber 3 and the side wall 4a of the processing chamber 4 in the processing container 1, and the dielectric wall 2 is placed on the support shelf 5.

[0026] In the antenna chamber 3, a high-frequency antenna 13 is disposed on the dielectric wall 2 so as to face the dielectric wall 2. The high-frequency antenna 13 is separated from the dielectric wall 2 by, for example, a range of 50 [mm] or less by a spacer 13a made of an insulating member. Near the central portion of the antenna chamber 3, four power supply members 16 extending in a direction perpendicular to the upper surface of the dielectric wall 2 (in the vertical direction) are provided, and a high-frequency power supply 15 is connected to the four power supply members 16 via a matcher 14. The power supply members 16 are arranged around the gas supply pipe 20a.

[0027] During plasma processing, plasma generation high-frequency power (RF) having a frequency of, for example, about 13.56 [MHz] for forming an induction electric field is supplied from the high-frequency power supply 15 into the processing chamber 4 through the high-frequency antenna 13. By supplying the plasma generation high-frequency power from the high-frequency power supply 15 into the processing chamber 4 in this way, an induction electric field is formed in the processing chamber 4, and the plasma of the processing gas supplied from the shower housing 11 into the processing chamber 4 is generated by this induction electric field. The shower housing 11 is provided in a cross shape, and the supply of the high-frequency power from the high-frequency antenna 13 into the processing chamber 4 is not hindered even if the shower housing 11 is made of metal.

[0028] A mounting table 22 is provided below (on the side opposite to the dielectric wall 2) inside the processing chamber 4. The mounting table 22 faces the high-frequency antenna 13 with the dielectric wall 2 therebetween. A wafer W is placed on the mounting table 22. The mounting table 22 may contain a conductive material. The surface of the mounting table 22 may include, for example, anodized treatment or aluminum sprayed with alumina. The wafer W placed on the mounting table 22 is adsorbed and held on the mounting table 22 by an electrostatic chuck (not shown).

[0029] The mounting table 22 is housed in an insulator frame 24 and supported by a support column 25. The support column 25 has a hollow structure. A bellows 26 that hermetically surrounds the support column 25 is disposed between the insulator frame 24 that houses the mounting table 22 and the bottom of the processing container 1 (the side of the processing container 1 where the support column 25 is provided). An inlet / outlet 27a for loading and unloading the wafer W and a gate valve 27 for opening and closing the inlet / outlet 27a are provided on the side wall 4a of the processing chamber 4.

[0030] The mounting table 22 is connected to a high-frequency power supply 29 via a matcher 28 by a power supply rod 25a provided inside the support column 25. During plasma processing, the high-frequency power supply 29 applies bias high-frequency power, for example, bias high-frequency power having a frequency of about 400 [kHz] to 6 [MHz], to the mounting table 22. Due to this bias high-frequency power, ions in the plasma generated inside the processing chamber 4 can be effectively drawn into the wafer W.

[0031] Inside the mounting table 22, a temperature control mechanism including heating means such as a ceramic heater 21 and a refrigerant flow path and a temperature sensor are provided for the purpose of controlling the temperature of the wafer W (both are not shown). The temperature control mechanism, the temperature sensor, the piping and wiring for the members are all led out of the processing container 1 through the inside of the support column 25.

[0032] At the bottom of the processing chamber 4 (the side of the processing chamber 4 where the support column 25 is provided), an exhaust device 30 including a vacuum pump or the like is connected via an exhaust pipe 31. By the exhaust device 30, the processing chamber 4 is exhausted, and during plasma processing, the inside of the processing chamber 4 is set and maintained in a predetermined vacuum atmosphere (for example, an atmospheric pressure of about 1.33 [Pa]).

[0033] The high-frequency antenna 13 has four power supply parts (for example, the power supply part 41, the power supply part 43, etc.). The four power supply parts are connected to the power supply member 16. The four power supply parts are separated from each other by about 90 degrees around the center of the high-frequency antenna 13. Two antenna lines extend outward from each of the four power supply parts, and each antenna line is grounded via a capacitor 18.

[0034] The plasma processing apparatus 10 includes a control unit Cnt. The control unit Cnt is a computer including a processor, a storage unit, an input device, a display device, etc., and controls each part of the plasma processing apparatus 10. When the control unit Cnt is provided outside the plasma processing apparatus 10, the control unit Cnt can control the plasma processing apparatus 10 by means of communication such as wired or wireless.

[0035] The control unit Cnt operates according to a program based on the input recipe and sends out a control signal. By the control signal from the control unit Cnt, it is possible to control the selection and flow rate of the gas supplied from the processing gas supply system 20, the exhaust of the exhaust device 30, the power supply from the high-frequency power supply 15 and the high-frequency power supply 29, and the temperature of the mounting table 22. Each step of the processing of the substrate disclosed in this specification (steps S1 to S2 shown in FIG. 1) can be executed by operating each part of the plasma processing apparatus 10 under the control of the control unit Cnt.

[0036] [Substrate Processing Method] Referring to FIGS. 3 and 4, an example of a substrate processing method ST according to an embodiment will be described. FIG. 3 is a flowchart showing an example of a substrate processing method ST according to an embodiment. FIG. 4 is an example of a cross-sectional schematic view of a wafer W for each step. Here, an example will be described in which a SiOF film is formed as an insulating layer on a wafer W using a plasma processing apparatus 10, and then treatment processes (reduction treatment, stabilization treatment) described later are performed.

[0037] In step S11, the control unit Cnt prepares a wafer W in the processing container 1 and performs a film formation process. Specifically, the gate valve 27 is opened with the mounting table 22 lowered to the transfer position. Subsequently, the wafer W is carried into the processing container 1 through the carry-in / carry-out port 27a by a transfer arm (not shown) and placed on the mounting table 22 heated to a predetermined temperature (for example, room temperature to 350° C.) by the ceramic heater 21. Subsequently, the mounting table 22 is raised to the processing position, and the inside of the processing container 1 is depressurized to a predetermined degree of vacuum by the exhaust device 30. After depressurization, the control unit Cnt opens the valve 56d and controls the flow rate controller 56c to supply Ar gas from the Ar gas supply source 56a. Thereby, the inside of the processing container 1 (processing chamber 4) stabilizes at a predetermined pressure.

[0038] The wafer W prepared in the processing container 1 has an insulating layer 101 and a conductive layer 102 as shown in FIG. 4(a). The surface of the wafer W is formed by performing CMP (Chemical-Mechanical-Polishing or Planarization) after the implementation of damascene. The conductive layer 102 is formed through the implementation of damascene. The conductive layer 102 is embedded in the insulating layer 101 on the surface of the wafer W, and the surface of the conductive layer 102 and the surface of the insulating layer 101 are exposed on the surface side of the wafer W. The material of the conductive layer 102 can be any one of, for example, copper (Cu), aluminum (Al), ruthenium (Ru), titanium (Ti), molybdenum (Mo), cobalt (Co), tungsten (W), and tantalum (Ta).

[0039] The wafer W prepared in the processing container 1 may have a semiconductor layer instead of the conductive layer 102 shown in FIG. 4(a). In this case, the semiconductor layer is embedded in the insulating layer 101 on the surface of the wafer W, and the surface of the semiconductor layer and the surface of the insulating layer 101 are exposed on the surface side of the wafer W. The material of the semiconductor layer can be, for example, silicon (Si) or IGZO of an oxide semiconductor.

[0040] The material of the insulating layer 101 can be a Low-K film or a metal oxide insulating film. Also, the material of the insulating layer 101 is SiO, where x and y are natural numbers. x SiN x SiC x SiOC, SiOCH, Al x O y and the like can be insulating films.

[0041] In step S11, the control unit Cnt performs a film formation process on the wafer W. As an example of the film formation process, as shown in FIG. 4(b), a SiOF film 103 is selectively formed on the surface of the insulating layer 101. Therefore, the SiOF film 103 is not formed on the surface of the conductive layer 102.

[0042] In the film formation process of the SiOF film 103, the control unit Cnt opens the valve 52d while maintaining the supply of Ar gas, and controls the flow rate controller 52c to supply O2 gas from the O2 gas supply source 52a.

[0043] Next, the control unit Cnt supplies high-frequency power for plasma generation (RF) to the processing chamber 4 through the high-frequency antenna 13 by the high-frequency power supply 15 to generate plasma from the O2 gas.

[0044] Next, the control unit Cnt opens the valve 51d, controls the flow rate controller 51c to supply SiF4 gas from the SiF4 gas supply source 51a. The control unit Cnt supplies high-frequency power for plasma generation to the processing chamber 4 through the high-frequency antenna 13 by the high-frequency power supply 15 to generate plasma from the SiF4 gas. The generation of the plasma of the SiF4 gas may be simultaneous with the generation of the plasma of the O2 gas or after the generation of the plasma of the O2 gas.

[0045] An SiOF film is formed on the wafer W by the plasma of O2 gas and SiF4 gas. When a predetermined time has elapsed, the control unit Cnt closes the valves 56d, 52d, and 51d, stops the supply of Ar gas, O2 gas, and SiF4 gas, and discharges the gas from the processing chamber 4.

[0046] If the reduction process described later is not performed in this state, particularly the surface of the conductive layer 102 is corroded and corrosion occurs. As a result, as shown in FIG. 4(c), a halide 104 is formed on the conductive layer 102. Therefore, the control unit Cnt performs a reduction process to suppress corrosion after performing the film formation process in step S11.

[0047] In order to increase the reduction efficiency in step S13, in step S12, the control unit Cnt opens the valve 53d, controls the flow rate controller 53c to supply H2 gas from the H2 gas supply source 53a, and controls the pressure in the processing container 1 to be in the range of 20 Pa to 100 Pa. The control unit Cnt purges the inside of the processing chamber 4 while maintaining the supply of H2 gas. Here, the control unit Cnt controls the pressure in the processing chamber 4 to be 20 Pa or more and 100 Pa or less by controlling the exhaust device 30 while controlling the flow rate of H2 gas from the H2 gas supply source 53a by the flow rate controller 53c.

[0048] FIG. 5 is a graph showing an example of the relationship between the pressure in the processing chamber 4 and the ion energy. Pressure on the horizontal axis indicates the pressure in the processing chamber 4, and ion energy on the vertical axis indicates the ion energy. In the graph, the ion energy decreases as the pressure in the processing chamber 4 increases. In the range of 20 Pa or more and 100 Pa or less, since the ion energy is small, the damage by ions is small and the roughness (surface roughness) of the surface of the wafer W is improved.

[0049] When the flow rate of H2 gas and the pressure in the processing chamber 4 are adjusted, the process of the control unit Cnt proceeds to step S13. In step S13, while maintaining the supply of H2 gas, the control unit Cnt supplies a first gas containing hydrogen and nitrogen into the processing chamber 4, and exposes the wafer W to the plasma generated from the first gas. The first gas may be either N2 gas or NH3 gas. Here, as an example, H2 gas and N2 gas are supplied as the first gas.

[0050] The control unit Cnt further opens the valve 54d with the valve 53d open, controls the flow controllers 53c and 54c, and supplies H2 gas and N2 gas from the H2 gas supply source 53a and the N2 gas supply source 54a into the processing chamber 4. The control unit Cnt supplies high-frequency power for plasma generation (RF) to the processing chamber 4 via the high-frequency antenna 13 by the high-frequency power supply 15, and generates plasma from H2 gas and N2 gas in the processing chamber 4. By exposing the generated plasma to the wafer W, the surface of the conductive layer 102 is reduced. When a predetermined time has elapsed, the control unit Cnt closes the valves 53d and 54d, stops the supply of H2 gas and N2 gas, and discharges the gas from the processing chamber 4.

[0051] In the reduction process, when the first gas contains H2 gas and does not contain N2 gas, it is difficult to reduce the surface of the conductive layer 102, and it is difficult to remove the halogen compound. On the other hand, when bias power is applied from the high-frequency power supply 29 to the mounting table 22 to give ion energy to remove the halogen compound, the roughness of the surface of the conductive layer 102 deteriorates.

[0052] In order to make it easier to reduce the surface of the conductive layer 102, promote the removal of the halogen compound, and keep the roughness of the surface of the conductive layer 102 in a good state, the first gas is a mixed gas containing a small amount of N2 gas in H2 gas. Thereby, it becomes easier to reduce the surface of the conductive layer 102 by the plasma of H2 and N2. As a result, as shown in FIG. 4(d), the halide 104 is removed from the surface of the conductive layer 102. However, the surface of the conductive layer 102 becomes unstable (active), and a modified layer 105 is generated on the surface of the conductive layer 102, or some halide 104 remains.

[0053] Therefore, in step S14, the control unit Cnt forms a stabilization layer by adsorbing silicon or aluminum onto the conductive layer 102 by exposing the conductive layer 102 to the second gas.

[0054] In this stabilization process, the valve 56d is opened, the flow controller 56c is controlled to supply Ar gas from the Ar gas supply source 56a into the processing chamber 4, and a second gas containing hydrogenated silicon or alkylated aluminum is supplied into the processing chamber 4. The second gas contains any one of SiH4, Si2H6, TMA (Al(CH3)2), or TMAH (AlH(CH3)2). Here, as an example of the second gas, SiH4 gas is supplied.

[0055] The control unit Cnt opens the valve 55d, controls the flow controller 55c to supply SiH4 gas from the SiH4 gas supply source 55a into the processing chamber 4. By exposing the wafer W to the SiH4 gas, silicon is adsorbed and stabilized on the surface of the conductive layer 102.

[0056] As a result, as shown in FIG. 4(e), a stabilization layer 106 is formed on the surface of the conductive layer 102, the alteration of the surface of the conductive layer 102 can be prevented or suppressed, and the corrosion can be suppressed.

[0057] In step S14, the control unit Cnt may control the temperature of the mounting table 22 to be equal to or higher than room temperature and 350°C or lower, which can be temperature-controlled by the ceramic heater 21. Thereby, silicon or aluminum contained in the second gas can be adsorbed onto the conductive layer 102 whose surface is reduced, and the stabilization layer 106 can be formed. However, in order to more reliably form the stabilization layer 106, it is preferable to control the temperature of the mounting table 22 to be equal to or higher than room temperature and 100°C or lower.

[0058] In step S14, no plasma is generated from the second gas. This is because if plasma is used, a silicon film will be formed on the conductive layer 102, and silicon or aluminum contained in the second gas cannot be adsorbed onto the conductive layer 102 to form the stabilization layer 106. Note that the stabilization layer 106 does not have to be in a layered form, as long as the surface of the conductive layer 102 is in a stable state. After the execution of step S14, the control unit Cnt ends the substrate processing method ST.

[0059] In the reduction treatment and the stabilization treatment, a vacuum atmosphere is preferable, and an atmosphere-controlled treatment may also be used. When the atmosphere is controlled, a gas that does not react or hardly reacts with the active surface can be used as the atmosphere gas.

[0060] According to the substrate processing method ST, in the reduction treatment, the surface of the conductive layer 102 is exposed to the plasma of the first gas to clean the surface of the conductive layer 102. Next, in the stabilization treatment, the surface of the conductive layer 102, which has become unstable (active) by the reduction treatment, is treated with a second gas such as SiH4 gas or TMA to stabilize the surface of the conductive layer 102. Thereby, it is possible to suppress the corrosion and the formation of the altered layer 105 on the surface of the conductive layer 102.

[0061] Also, in the reduction treatment, by controlling the pressure in the processing chamber 1 within the range of 20 Pa to 100 Pa, the ion energy can be reduced. Thereby, the damage caused by ions is small, and the roughness (surface roughness) of the surface of the conductive layer 102 can be improved. Thereby, it is possible to achieve both suppression of corrosion and good roughness on the surface of the conductive layer 102.

[0062] [Experimental Results] In the reduction process, the ratio of hydrogen atoms to the sum of hydrogen and nitrogen atoms in the first gas (hereinafter referred to as H / H+N) may be 0.75 to less than 1 (0.99). The ratio of hydrogen atoms to the sum of hydrogen and nitrogen atoms in the first gas (H / H+N) may be 0.95 to less than 1 (0.99). Hereinafter, with reference to FIGS. 6 and 7, the experimental results regarding the numerical value of H / H+N will be described.

[0063] FIG. 6 is a graph showing an example of the relationship between the ratio of H atoms to the sum of H and N atoms (H / H+N) and the contact angle θe. The horizontal axis of FIG. 6 indicates H / H+N, and the vertical axis indicates the contact angle θe of water. FIG. 7 is a graph showing an example of the relationship between the ratio of H atoms to the sum of H and N atoms (H / H+N) and the surface roughness. The horizontal axis of FIG. 7 indicates H / H+N, and the vertical axis indicates the roughness (RMS). In the experiments of FIGS. 6 and 7, a Cu film formed by plating was used for the conductive layer 102.

[0064] The ● (black circle) in FIGS. 6 and 7 shows the relationship between the contact angle θe and the roughness by converting the ratio of H2 gas to the sum of H2 and N2 gases (H2 / H2+N2) to H / H+N when the first gas is a mixed gas of H2 gas and N2 gas. The △ (triangle) in FIGS. 6 and 7 shows the relationship between the contact angle θe and the roughness by converting the ratio of H2 gas to the sum of H2 and NH3 gases (H2 / H2+NH3) to H / H+N when the first gas is a mixed gas of H2 gas and NH3 gas. The 〇 (white circle) in FIGS. 6 and 7 shows the relationship between the contact angle θe and the roughness by converting the ratio of N2 gas to NH3 (N2 / NH3) to H / H+N with H:N = 3:1 for H and N in NH3 when the first gas is a mixed gas of N2 gas and NH3 gas.

[0065] The graph in FIG. 6 shows the results of exposing the surface of the conductive layer 102 of the Cu film formed by copper plating to the plasma generated from each of the above three types of mixed gases. The graph shows the hydrophilic behavior of the surface of the conductive layer 102 at the contact angle θe of water on the vertical axis.

[0066] According to this, the surface of the conductive layer 102 was cleaned by the reduction treatment and became hydrophilic, and the angle of the contact angle θe changed in the direction of increasing. If the contact angle θe is 40 degrees to 45 degrees, it can be determined that the surface of the conductive layer 102 is clean. Further, if the contact angle θe is substantially constant at 40 degrees to 45 degrees or more, it can be determined that the surface of the conductive layer 102 has not changed in the cleaned state.

[0067] From the graph, when the first gas is a mixed gas of H2 gas and N2 gas (●) and when the first gas is a mixed gas of H2 gas and NH3 gas (△), the contact angle θe becomes approximately 45 degrees or more in the range where H / (H + N) is 0.75 to less than 1, and the hydrophilicity of the surface of the conductive layer 102 was high. That is, the surface of the conductive layer 102 was cleaned. In particular, when the first gas is a mixed gas of H2 gas and N2 gas (●), the contact angle θe is higher than 45 degrees in the range where H / (H + N) is 0.95 to less than 1, and the hydrophilicity of the surface of the conductive layer 102 was even higher. That is, the surface of the conductive layer 102 was further cleaned. Further, from the graph, when the first gas is a mixed gas of N2 gas and NH3 gas (〇), in the range where H / (H + N) is about 0.5 to about 0.7, the contact angle θe becomes substantially constant at 40 degrees to 45 degrees or more, and the surface of the conductive layer 102 was cleaned.

[0068] In the graph of FIG. 7, when the roughness becomes about 1 nm or less, it indicates that the roughness of the surface of the conductive layer 102 is good. That is, there are no irregularities on the surface of the conductive layer 102, and it shows a flat state.

[0069] From the graph, when the first gas is a mixed gas of H2 gas and N2 gas (●) and when the first gas is a mixed gas of H2 gas and NH3 gas (△), the roughness becomes generally on the order of 1 nm, and the surface of the conductive layer 102 becomes flat and in a good state. On the other hand, when the first gas is a mixed gas of N2 gas and NH3 (〇), the roughness becomes about twice that of the order of 1 nm, and the surface of the conductive layer 102 becomes in a bad state where it is not flattened.

[0070] From the above, when the first gas is a mixed gas of H2 gas and N2 gas, or a mixed gas of N2 gas and NH3 gas, both the cleaning of the surface of the conductive layer 102 and the roughness of the surface of the conductive layer 102 resulted in favorable outcomes. That is, it was found that either a mixed gas of H2 gas and N2 gas or a mixed gas of N2 gas and NH3 gas can be used as the first gas for the reduction treatment.

[0071] FIG. 8 is an example of a cross-sectional schematic view of the wafer W with and without the stabilization treatment. In the experiment of FIG. 8, a Cu film formed by plating was used for the conductive layer 102. Also, in the stabilization process, the atmosphere was controlled to a vacuum atmosphere, and a mixed gas of H2 gas and N2 gas was used as the second gas. Under these conditions, after performing the reduction treatment, the TEM image on the conductive layer 102 when the stabilization treatment was not performed is shown in FIG. 8(a). In FIG. 8(a), an unstable altered layer 105 was formed on the surface of the Cu film of the conductive layer 102. At this time, the wafer W was not exposed to the atmosphere. Then, the wafer W was exposed to the atmosphere for 2 hours. The TEM image on the conductive layer 102 after the wafer W was exposed to the atmosphere for 2 hours is shown in FIG. 8(b).

[0072] In FIG. 8(b), the unstable altered layer 105 on the surface of the conductive layer 102 became thicker. It is considered that when the wafer W having the halogenated conductive layer 102 was exposed to the atmosphere, corrosion occurred due to the reaction of the surface of the conductive layer 102 with water, and the altered layer 105 became thicker.

[0073] In FIGS. 8(a) and (b), the stabilization treatment was not performed after the reduction treatment. In contrast, the TEM image on the conductive layer 102 after performing the stabilization treatment without exposing to the atmosphere after the reduction treatment is shown in FIG. 8(c).

[0074] In FIG. 8(c), the altered layer 105 on the surface of the conductive layer 102 was significantly improved. FIG. 8(d) shows a TEM image on the conductive layer 102 after being exposed to the atmosphere for 2 hours from the state of FIG. 8(c). In FIG. 8(d), the altered layer 105 on the surface of the conductive layer 102 has not changed from the significantly improved state of FIG. 8(c), and the corrosion was suppressed by the stabilizing layer on the surface of the conductive layer 102.

[0075] FIGS. 9 and 10 are graphs showing an example of the XPS analysis results of the Cu film formed on the substrate. Here, to simulate the conductive layer 102, XPS analysis was performed on a wafer on which a Cu film was formed by plating in an experiment.

[0076] "Initial" indicated by the dashed line in FIGS. 9(a) to 9(d) shows the XPS analysis results of the surface of the Cu film before performing the reduction treatment on the wafer on which the Cu film was formed. "H2Vessel" indicated by the broken line shows the XPS analysis results of the surface of the Cu film after reducing the Cu film using H2 plasma for the wafer on which the Cu film was formed. "H2 / N2Vessel" indicated by the solid line shows the XPS analysis results of the surface of the Cu film after reducing the Cu film using plasma with a small amount of N2 gas added to H2 gas for the wafer on which the Cu film was formed. In this experiment, H / H+N was set to 0.95. The horizontal axis indicates the binding energy, and the vertical axis indicates the number of detections per unit time.

[0077] FIG. 9(a) shows the XPS analysis results of C1s. FIG. 9(b) shows the XPS analysis results of O1s. FIG. 9(c) shows the XPS analysis results of Cu 2p. FIG. 9(d) shows the XPS analysis results of Cu LMM.

[0078] From the results of FIGS. 9(a) and 9(b), when comparing "Initial" and "H2Vessel", by reducing the Cu film using H2 plasma, the oxygen incorporated on the surface of the Cu film decreased, and the oxidation state of the surface of the Cu film was improved.

[0079] In addition, by reducing the Cu film using a plasma with a small amount of N2 gas added to H2 gas, as shown in "H2 / N2 Vessel", oxygen was efficiently removed from the surface of the Cu film in a state of low ion energy.

[0080] On the other hand, from the results of FIGS. 9(c) and (d), after the reduction treatment, the surface of the Cu + film was altered to an unstable state with a large amount of Cu in this state. This is consistent with the formation of the altered layer shown in FIGS. 8(a) and (b).

[0081] FIG. 10 is a graph showing an example of the presence or absence of stabilization treatment and the XPS analysis results. FIG. 10(a) is the same graph as FIG. 9(d), and the surface of the Cu after the reduction treatment was altered by the reoxidation of Cu to form an altered layer. In contrast, FIG. 10(b) shows the surface of the Cu film after supplying SiH4 gas to the surface of the Cu after the reduction treatment and performing a stabilization treatment.

[0082] "Initial" indicated by the dashed-dotted line in FIG. 10(b) shows the XPS analysis results of the surface of the Cu film before performing the stabilization treatment on the wafer on which the Cu film was formed. "H2+SiH4 Flow atm" indicated by the two-dot chain line shows the XPS analysis results of the surface of the Cu film after performing the reduction treatment on the wafer on which the Cu film was formed using H2 plasma and then exposing the surface of the Cu film to SiH4 gas for stabilization treatment. "H2 / N2+SiH4 Flow atm" indicated by the broken line shows the XPS analysis results of the surface of the Cu film after performing the reduction treatment on the wafer on which the Cu film was formed using a plasma with a small amount of N2 gas added to H2 gas and then exposing the surface of the Cu film to SiH4 gas for stabilization treatment. "H2 / NH3+SiH4 Flow atm" indicated by the dotted line shows the XPS analysis results of the surface of the Cu film after performing the reduction treatment on the wafer on which the Cu film was formed using a plasma with a small amount of NH3 gas added to H2 gas and then exposing the surface of the Cu film to SiH4 gas for stabilization treatment. In this experiment, H / H+N = 0.95. The horizontal axis indicates the binding energy, and the vertical axis indicates the number of detections per unit time.

[0083] According to this, after the stabilization treatment is performed on the wafer on which the Cu film is formed, the Cu surface is more stable than before the stabilization treatment, and the altered layer is significantly improved. This is consistent with the significant improvement in the altered layer shown in Fig. 8(c) and the stabilization of the Cu surface.

[0084] An example of the process conditions of the above experiment is shown. (Reduction treatment) ·H2 plasma H2 gas: 500 sccm Pressure: 20 Pa Temperature: 100 °C RF power: 2000 W (upper electrode) / 50 W (lower electrode) ·H2 / N2 plasma H2 gas: 475 sccm N2 gas: 25 sccm Pressure: 20 Pa Temperature: 100 °C RF power: 1000 W (upper electrode)

[0085] (Stabilization treatment) ·SiH4 flow SiH4 gas: 36 sccm Pressure: 15 Pa Temperature: 100 °C

[0086] [Others] According to the substrate processing method ST according to this embodiment, it is possible to suppress the corrosion of the surface of the conductive layer or the semiconductor layer formed using the precursor of the halogen-containing gas. However, it is not limited to this, and it can be preferably applied to the conductive layer of the underlying layer when a process is performed using a halogen-containing gas, such as etching with a halogen-containing gas. For example, the process shown in step S11 (film formation process) in Fig. 3 may be a process other than the film formation process, such as etching using a halogen-containing gas.

[0087] The processes shown in steps S11 to S14 of FIG. 3 are preferably carried out in a vacuum atmosphere, and may also be processes with controlled atmosphere. Further, the processes shown in steps S11 to S14 may be configured to be carried out in the same substrate processing apparatus. Further, the substrate processing apparatus for performing the process shown in step S11, the substrate processing apparatus for performing the processes shown in steps S12 and S13, and the substrate processing apparatus for performing the process shown in step S14 may be connected in a vacuum transfer chamber or a transfer chamber with controlled atmosphere. Thereby, after the reduction step shown in step S13 and before the stabilization step shown in step S14, the wafer W is not exposed to the atmosphere, so that it is possible to suppress the formation of an unstable altered layer on the surface of the conductive layer 102.

[0088] The substrate processing apparatus is not limited to single-wafer processing apparatuses such as CVD (Chemical Vapor Deposition) and ALD that process wafers one by one. For example, the substrate processing apparatus may be a batch-type processing apparatus that holds a plurality of wafers in a wafer boat and carries them into a processing container, and performs processing on the plurality of wafers at once. Further, for example, the substrate processing apparatus may be a semi-batch type apparatus that revolves a plurality of wafers arranged on a rotating table in a processing container by the rotating table, and passes through a region where one gas is supplied and a region where another gas is supplied in order to perform processing on the wafers. Further, for example, the film forming apparatus may be a multi-wafer film forming apparatus having a plurality of mounting tables in one processing container.

[0089] As described above, according to the substrate processing method and the substrate processing apparatus of the present embodiment, it is possible to suppress the corrosion of the surface of the conductive layer or the semiconductor layer.

[0090] The substrate processing method and the substrate processing apparatus according to the embodiment disclosed this time should be considered to be illustrative and not restrictive in all respects. The embodiment can be modified and improved in various forms without departing from the scope and gist of the appended claims. The matters described in the above plurality of embodiments can also adopt other configurations and can be combined within a non-contradictory range.

Description of Symbols

[0091] 1…Processing container, 1a…Grounding wire, 2…Dielectric wall, 3…Antenna chamber, 3a…Side wall, 4…Processing chamber, 4a…Side wall, 5…Support shelf, 10…Plasma processing apparatus, 11…Shower housing, 12…Gas flow path, 12a…Gas supply hole, 13…High-frequency antenna, 13a…Spacer, 14…Matcher, 15…High-frequency power supply, 16…Power feeding member, 18…Capacitor, 20…Processing gas supply system, 20a…Gas supply pipe, 21…Ceramic heater, 22…Mounting table, 24…Insulator frame, 25…Support column, 25a…Power feeding rod, 26…Bellows, 27…Gate valve, 27a…Loading / unloading port, 28…Matcher, 29…High-frequency power supply, 30…Exhaust device, 31…Exhaust pipe, 41…Power feeding part, 43…Power feeding part, 51a…SiF4 gas supply source, 52a…O2 gas supply source, 53a…H2 gas supply source, 54a…N2 gas supply source, 55a…SiH4 gas supply source, 56a…Ar gas supply source, 101…Insulating layer, 102…Conductive layer, 103…SiOF film, Cnt…Control unit, W…Wafer.

Claims

1. A step of preparing a substrate having a conductive layer or a semiconductor layer in a processing container; A step of supplying a first gas containing hydrogen and nitrogen into the processing container, and exposing the substrate to plasma generated from the first gas to reduce the surface of the conductive layer or the semiconductor layer; A step of supplying a second gas containing hydrogenated silicon or alkylated aluminum, and exposing the reduced conductive layer or semiconductor layer to the second gas to adsorb silicon or aluminum onto the conductive layer or the semiconductor layer to form a stabilization layer; A substrate processing method comprising the above steps.

2. The ratio of hydrogen atoms to the sum of hydrogen atoms and nitrogen atoms contained in the first gas is less than 0.75 to 1. The substrate processing method according to Claim 1.

3. The first gas is H ２ gas and N ２ gas mixed gas, H ２ gas and NH ３ gas mixed gas, any of which, The substrate processing method according to Claim 2.

4. The ratio of hydrogen atoms to the sum of hydrogen atoms and nitrogen atoms contained in the first gas is less than 0.95 to 1. The substrate processing method according to Claim 2.

5. The first gas is H ２ gas and N ２ gas, a mixed gas of The substrate processing method according to Claim 4.

6. The second gas contains any one of SiH ４ , Si ２ H ６ , TMA (Al(CH ３ )) ２ ), or TMAH (AlH(CH ３ )) ２ ). The substrate processing method according to any one of Claims 1 to 5.

7. In the step of reducing, the pressure in the processing container is 20 Pa to 100 Pa. The substrate processing method according to any one of Claims 1 to 5.

8. The conductive layer is any one of Cu, Al, Ru, Ti, Mo, Co, W, and Ta. The substrate processing method according to any one of Claims 1 to 5.

9. The semiconductor layer is Si. The substrate processing method according to any one of Claims 1 to 5.

10. In the step of forming the stabilization layer, the temperature in the processing container is from room temperature to 350 °C. The substrate processing method according to any one of Claims 1 to 5.

11. In the step of forming the stabilization layer, the temperature in the processing container is from room temperature to 100 °C. The substrate processing method according to Claim 10.

12. A processing container; A gas supply unit for supplying gas into the processing container; A power supply for supplying high-frequency power into the processing container; A control unit, and The control unit prepares a substrate having a conductive layer or a semiconductor layer in the processing container; supplies a first gas containing hydrogen and nitrogen from the gas supply unit into the processing container, and exposes the substrate to plasma generated from the first gas to reduce the surface of the conductive layer or the semiconductor layer; A second gas containing hydrogenated silicon or alkylated aluminum is supplied from the gas supply unit, and the reduced conductive layer or semiconductor layer is exposed to the second gas, thereby adsorbing silicon or aluminum on the conductive layer or semiconductor layer to form a stabilization layer; A substrate processing apparatus that controls the above.

Images