WO2020149176A1

WO2020149176A1 - Substrate processing method and substrate processing system

Info

Publication number: WO2020149176A1
Application number: PCT/JP2020/000197
Authority: WO
Inventors: 久志源島; 村松　誠; 寛之藤井; 大和戸根川
Original assignee: 東京エレクトロン株式会社
Priority date: 2019-01-16
Filing date: 2020-01-07
Publication date: 2020-07-23
Also published as: TW202101590A

Abstract

A substrate processing method according to one aspect of the present disclosure comprises: a step for forming a coating film by applying a polysilazane composition to a substrate; a step for removing a solvent from the coating film; a step for subjecting the coating film, from which the solvent has been removed, to a plasma processing that is performed by means of a plasma of an inert gas; and a step for subjecting the coating film, which has been subjected to the plasma processing, to a heat treatment.

Description

Substrate processing method and substrate processing system

The present disclosure relates to a substrate processing method and a substrate processing system.

Patent Document 1 discloses a method for forming a silicon nitride thin film (silicon nitride film) in which perhydropolysilazane or a modified product thereof is applied on a substrate and then baked at a temperature of 600° C. or higher under vacuum. ..

Japanese Patent Laid-Open No. 10-194873

The present disclosure provides a substrate processing method and a substrate processing system capable of improving the quality of a silicon nitride film formed from a coating film containing a polysilazane compound.

A substrate processing method according to one aspect of the present disclosure is to apply a polysilazane composition to a substrate to form a coating film, remove a solvent in the coating film, and remove the solvent from the coating film. , Performing plasma treatment with plasma of an inert gas and heat treating the coating film subjected to the plasma treatment.

According to the present disclosure, there is provided a substrate processing method and a substrate processing system capable of improving the quality of a silicon nitride film formed from a coating film containing a polysilazane compound.

FIG. 1 is a schematic diagram illustrating a schematic configuration of a substrate processing system. FIG. 2 is a schematic diagram illustrating the internal configuration of the coating and developing apparatus. FIG. 3 is a schematic view illustrating the configuration of the coating unit. FIG. 4 is a schematic view illustrating the configuration of the heat treatment unit. FIG. 5 is a schematic diagram illustrating the configuration of the plasma processing apparatus. FIG. 6 is a flowchart showing an example of a procedure for forming a silicon nitride film. FIG. 7A is a graph showing the component analysis result when the plasma treatment is not performed. FIG. 7B is a graph showing the component analysis result when the plasma treatment is performed. FIG. 8A is a graph showing the component analysis result when the plasma treatment is not performed. FIG. 8B is a graph showing the result of component analysis when plasma processing is performed. FIG. 9A and FIG. 9B are graphs showing another component analysis result when the plasma treatment is not performed. FIG. 10A and FIG. 10B are graphs showing another component analysis result when plasma processing is performed. FIG. 11 is a graph showing the measurement results of the film thickness in Examples and Comparative Examples. FIG. 12 is a graph showing the evaluation results of the refractive index in Examples and Comparative Examples. FIG. 13 is a graph showing an example of the analysis result of the density of the coating film before and after the plasma treatment. FIG. 14 is a graph showing the evaluation results of etching rates in the examples and comparative examples. FIG. 15 is a graph showing the evaluation results of etching rates in the examples and comparative examples. FIG. 16A is a graph showing the measurement result of the film thickness when the type of plasma is changed. FIG. 16B is a graph showing the measurement results of the refractive index when the type of plasma is changed. FIG. 17 is a schematic diagram illustrating the configuration of the plasma processing apparatus. FIG. 18 is a graph showing the measurement results of film thickness in Examples. FIG. 19 is a graph showing the evaluation results of the refractive index in the examples. FIG. 20 is a graph showing the evaluation results of etching rates in Examples and Comparative Examples. FIG. 21 is a schematic view illustrating the configuration of the coating unit. FIG. 22 is a graph showing the result of component analysis when atmosphere control is performed. FIG. 23 is a graph showing the evaluation result of the etching rate in the example.

Hereinafter, various exemplary embodiments will be described. In the description, the same elements or elements having the same function will be denoted by the same reference symbols, without redundant description.

[Substrate processing system]
First, a schematic configuration of the substrate processing system 1 will be described with reference to FIGS. 1 and 2. The substrate processing system 1 is a system for forming an insulating film, a photosensitive film, exposing the photosensitive film, and developing the photosensitive film on a substrate. The substrate to be processed is, for example, a semiconductor wafer W. The substrate processing system 1 forms a silicon nitride film (SiN film) as an insulating film on the wafer W. Specifically, the substrate processing system 1 applies the polysilazane composition to the wafer W to form a coating film, and forms the silicon nitride film by subjecting the coating film to the processing described later. The photosensitive film is, for example, a resist film. The substrate processing system 1 includes a coating/developing apparatus 2, an exposure apparatus 3, a plasma processing apparatus 10, and a control apparatus 100. The exposure device 3 is a device that exposes a resist film (photosensitive film) formed on the wafer W (substrate). Specifically, the exposure apparatus 3 irradiates the exposed portion of the resist film with energy rays by a method such as liquid immersion exposure. The coating/developing apparatus 2 applies a part of the process of forming an insulating film of the polysilazane composition on the surface of the wafer W and the resist (chemical solution) on the surface of the wafer W (substrate) before the exposure process by the exposure device 3. A process of applying to form a resist film is performed. In addition, the coating/developing device 2 performs a developing process for the resist film after the exposure process.

(Coating/developing device)
As shown in FIGS. 1 and 2, the coating/developing apparatus 2 includes a carrier block 4, a processing block 5, and an interface block 6.

The carrier block 4 introduces the wafer W into the coating/developing apparatus 2 and guides the wafer W from the coating/developing apparatus 2. For example, the carrier block 4 can support a plurality of carriers C for the wafer W, and has a built-in transfer device A1 including a transfer arm. The carrier C accommodates a plurality of circular wafers W, for example. The transfer device A1 takes out the wafer W from the carrier C, transfers the wafer W to the processing block 5, receives the wafer W from the processing block 5, and returns the wafer W into the carrier C. The processing block 5 has a plurality of

processing modules

11, 12, 13, and 14.

The processing module 11 includes a coating unit U1, a heat treatment unit U2, and a transfer device A3 that transfers the wafer W to these units. The processing module 11 performs a part of the processing of forming an insulating coating on the surface of the wafer W by the coating unit U1 and the heat treatment unit U2. The coating unit U1 (coating unit) coats a processing liquid for forming an insulating coating on the wafer W to form a coating film. The heat treatment unit U2 performs various heat treatments associated with the formation of the insulating coating. Specifically, the heat treatment unit U2 removes the solvent in the coating film by heating the coating film formed by coating the treatment liquid. In this case, the heat treatment unit U2 functions as a solvent removal unit. Further, the heat treatment unit U2 performs heat treatment for heating the coating film from which the solvent has been removed and which has been subjected to the plasma treatment described later by the plasma treatment device 10. In this case, the heat treatment unit U2 functions as a heat treatment unit.

The processing module 12 includes a coating unit U1, a heat treatment unit U2, and a transfer device A3 that transfers a wafer W to these units. The processing module 12 forms a resist film by the coating unit U1 and the heat treatment unit U2. The coating unit U1 coats a resist on the insulating coating as a treatment liquid for forming the coating. The heat treatment unit U2 performs various heat treatments associated with the formation of the coating. As a result, a resist film is formed on the surface of the wafer W.

The processing module 13 includes a coating unit U1, a heat treatment unit U2, and a transfer device A3 that transfers a wafer W to these units. The processing module 13 forms an upper layer film on the resist film by the coating unit U1 and the heat treatment unit U2. The coating unit U1 coats the processing liquid for forming the upper layer film on the resist film. The heat treatment unit U2 performs various heat treatments associated with the formation of the upper layer film.

The processing module 14 develops the exposed resist film by the coating unit U1 and the heat treatment unit U2. The coating unit U1 of the processing module 14 coats the surface of the exposed wafer W with the developing solution and then rinses it off with the rinse solution to develop the resist film. The heat treatment unit U2 performs various heat treatments associated with the development processing. Specific examples of heat treatment associated with the development treatment include heat treatment before the development treatment (PEB: Post Exposure Bake) and heat treatment after the development treatment (PB: Post Bake).

A shelf unit U10 is provided on the carrier block 4 side in the processing block 5. The shelf unit U10 is divided into a plurality of cells arranged in the vertical direction. A transfer device A7 including a lifting arm is provided near the shelf unit U10. The transfer device A7 moves the wafer W up and down between the cells of the shelf unit U10.

A shelf unit U11 is provided on the interface block 6 side in the processing block 5. The shelf unit U11 is divided into a plurality of cells arranged in the vertical direction.

The interface block 6 transfers the wafer W to and from the exposure apparatus 3. For example, the interface block 6 has a built-in transfer device A8 including a transfer arm and is connected to the exposure device 3. The transfer device A8 transfers the wafer W arranged on the shelf unit U11 to the exposure device 3. The transfer device A8 receives the wafer W from the exposure device 3 and returns it to the shelf unit U11.

(Coating unit)
Subsequently, an example of the coating unit U1 will be described in more detail with reference to FIG. As shown in FIG. 3, the coating unit U1 includes a rotation holding unit 20 and a liquid supply unit 30.

The rotation holding unit 20 has a rotation unit 21, a shaft 22, and a holding unit 23. The rotating unit 21 operates based on the operation signal from the control device 100 to rotate the shaft 22. The rotation unit 21 is, for example, a rotation actuator. The holding portion 23 is provided at the tip of the shaft 22. The wafer W is placed on the holding unit 23. The holding unit 23 holds the wafer W substantially horizontally, for example, by suction. That is, the rotation holding unit 20 rotates the wafer W around the central axis (rotation axis) perpendicular to the front surface Wa of the wafer W with the posture of the wafer W substantially horizontal. In the example of FIG. 3, the rotation holding unit 20 rotates the wafer W counterclockwise as viewed from above at a predetermined rotation speed.

The liquid supply unit 30 is configured to supply the processing liquid L1 to the front surface Wa of the wafer W. In the processing module 11, the processing liquid L1 is the coating liquid L for forming the insulating coating. In the processing module 12, the processing liquid L1 is a resist liquid for forming a resist film. In the processing module 13, the processing liquid L1 is a coating liquid for forming the upper layer film. In the processing module 14, the processing liquid L1 is a developing solution.

The coating liquid L for forming the insulating film is a polysilazane composition that is a material for the silicon nitride film. That is, the coating unit U1 of the processing module 11 coats the front surface Wa of the wafer W with the polysilazane composition to form the coating film AF on the wafer W. As this polysilazane composition, a conventionally known arbitrary polysilazane compound dissolved in a solvent can be used.

The polysilazane compound is not particularly limited and can be arbitrarily selected as long as the effects shown in the present disclosure are not impaired. The polysilazane compound may be either an inorganic compound or an organic compound. Examples of the polysilazane compound include those composed of a combination of units represented by the following general formulas (Ia) to (Ic):

(In the formula, m1 to m3 are numbers representing the degree of polymerization.)
As the polysilazane compound, those having a styrene-equivalent weight average molecular weight of 700 to 30,000 may be used among the above combinations.

In addition, examples of other polysilazane compounds include, for example, mainly the compound represented by the general formula (II):

(In the formula, R ¹ , R ² and R ³ are each independently a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, or a group other than these groups which is directly bonded to silicon such as a fluoroalkyl group. Represents a group which is carbon, an alkylsilyl group, an alkylamino group or an alkoxy group, provided that at least one of R ¹ , R ² and R ³ is a hydrogen atom, and n is a number representing the degree of polymerization. Examples thereof include polysilazane compounds having a skeleton composed of the structural unit and having a number average molecular weight of about 100 to 50,000 or modified products thereof. These polysilazane compounds may be used in combination of two or more kinds.

The polysilazane composition used in the present disclosure contains a solvent capable of dissolving the above polysilazane compound. Such a solvent is not particularly limited as long as it can dissolve the above polysilazane compound, but specific examples of the solvent include the following:
(A) Aromatic compounds such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene, triethylbenzene, etc. (b) Saturated hydrocarbon compounds such as n-pentane, i-pentane, n-hexane, i-hexane , N-heptane, i-heptane, n-octane, i-octane, n-nonane, i-nonane, n-decane, i-decane, etc., (c) alicyclic hydrocarbon compounds such as ethylcyclohexane, methylcyclohexane , Cyclohexane, cyclohexene, p-menthane, decahydronaphthalene, dipentene, limonene, etc., (d) ethers such as dipropyl ether, dibutyl ether, diethyl ether, methyl tertiary butyl ether (hereinafter referred to as MTBE), anisole, and the like, and (E) Ketones such as methyl isobutyl ketone (hereinafter referred to as MIBK). Of these, any one of (b) saturated hydrocarbon compound, (c) alicyclic hydrocarbon compound, (d) ether, and (e) ketone may be used as a solvent.

-These solvents may be appropriately mixed in two or more kinds in order to adjust the evaporation rate of the solvent, reduce the harmfulness to the human body, or adjust the solubility of each component.

The polysilazane composition may contain other additive components as needed. Examples of such components include a catalyst that accelerates the reaction such as a crosslinking accelerator that accelerates the crosslinking reaction of polysilazane, a viscosity modifier for adjusting the viscosity of the composition, and the like. In addition, a phosphorus compound such as tris(trimethylsilyl)phosphate may be contained for the purpose of gettering effect of sodium.

Also, the content of each of the above components changes depending on the coating conditions and heating conditions (heat treatment conditions). Moreover, the concentration of the polysilazane compound contained in the polysilazane composition is arbitrary. Further, the content of various additives other than the polysilazane compound varies depending on the kind of the additive and the like, but the amount added to the polysilazane compound may be, for example, 0.001 to 40% by weight. Alternatively, the added amount may be 0.005 to 30% by weight. Alternatively, the added amount may be 0.01 to 20% by weight.

The liquid supply unit 30 shown in FIG. 3 includes a liquid source 31, a pump 32, a valve 33, a nozzle 34, and a pipe 35. The liquid source 31 functions as a supply source of the processing liquid L1. The pump 32 operates based on the operation signal from the control device 100, sucks the processing liquid L1 from the liquid source 31, and sends it to the nozzle 34 via the pipe 35 and the valve 33.

The nozzle 34 is arranged above the wafer W so that the ejection port faces the front surface Wa of the wafer W. The nozzle 34 can discharge the processing liquid L1 sent from the pump 32 onto the front surface Wa of the wafer W. The pipe 35 connects the liquid source 31, the pump 32, the valve 33, and the nozzle 34 in order from the upstream side.

(Heat treatment unit)
Subsequently, an example of the heat treatment unit U2 will be described in more detail with reference to FIG. As shown in FIG. 4, the heat treatment unit U2 includes a heating plate 44, a chamber 40, a plurality of support pins 46, and a gas supply unit 50.

The hot plate 44 includes a heater 45. The heating plate 44 supports the wafer W to be heat-treated (object to remove the solvent) and heats the supported wafer W. The heat plate 44 is formed in a substantially disc shape as an example. The diameter of the heating plate 44 may be larger than the diameter of the wafer W. The heat plate 44 may be made of a metal having a high thermal conductivity, such as aluminum, silver, or copper. The heater 45 raises the temperature of the heating plate 44. The heater 45 may be composed of a resistance heating element. The heater 45 generates heat when a current according to an instruction from the control device 100 flows through the heater 45. Then, the heat from the heater 45 is transferred to raise the temperature of the heating plate 44.

The chamber 40 forms a heat treatment space for heat treatment. The chamber 40 includes an upper chamber 41 and a lower chamber 42. The upper chamber 41 is connected to a driving unit (not shown), and moves in the vertical direction with respect to the lower chamber 42. The upper chamber 41 includes a top plate facing the wafer W on the hot plate 44, and a sidewall surrounding the wafer W on the hot plate 44. The lower chamber 42 includes a holding portion 43 and holds a hot plate 44.

The support pins 46 are pins that support the wafer W from below. The support pin 46 extends in the vertical direction so as to penetrate the heating plate 44. The plurality of support pins 46 may be arranged at equal intervals in the circumferential direction around the center of the heating plate 44. The drive unit 47 moves the support pin 46 up and down according to an instruction from the control device 100. The drive unit 47 is, for example, a lift actuator.

The gas supply unit 50 is configured to supply gas into the chamber 40 (heat treatment space). For example, the gas supply unit 50 supplies nitrogen gas into the chamber 40. The gas supply unit 50 includes a gas supply source 53, a valve 52, and a pipe 54. The gas supply source 53 functions as a gas supply source. The valve 52 switches between an open state and a closed state according to an instruction from the control device 100. The gas supply source 53 sends out gas into the chamber 40 (heat treatment space) through the pipe 54 when the valve 52 is in the open state.

(Plasma processing device)
Subsequently, an example of the plasma processing apparatus 10 (plasma processing unit) will be described in more detail with reference to FIG. The plasma processing apparatus 10 performs plasma processing on a film containing a polysilazane compound formed by applying the polysilazane composition to the wafer W. For example, the plasma processing apparatus 10 may perform plasma processing on a coating film formed by coating the wafer W with the polysilazane composition, and plasma processing may be performed on the coating film from which the solvent has been removed by the heat treatment unit U2. May be given. In the present specification, “to perform plasma treatment” means that at least the front surface Wa of the wafer W is in contact with the plasma gas in a container containing a gas in a plasma state (hereinafter referred to as “plasma gas”). Thus, the wafer W is placed for a predetermined time.

The plasma processing apparatus 10 is connected to the coating/developing apparatus 2 via the transport mechanism 19 (see FIG. 2). The transfer mechanism 19 transfers the wafer W between the coating/developing apparatus 2 and the plasma processing apparatus 10. The plasma processing apparatus 10 is, for example, a parallel plate type apparatus. As shown in FIG. 5, the plasma processing apparatus 10 includes a processing container 68, a mounting table 60, a top plate section 70, a power supply section 80, and an exhaust section 90.

The processing container 68 has conductivity and is formed in a substantially cylindrical shape. A ground wire 69 is electrically connected to the processing container 68, and the processing container 68 is grounded.

The mounting table 60 is provided in the processing container 68 and supports the wafer W to be processed. The mounting table 60 includes a substantially disc-shaped electrostatic chuck 61 and a substantially annular focus ring 62. The electrostatic chuck 61 is a substantially disk-shaped member, and is formed, for example, by sandwiching an electrostatic chuck electrode between a pair of ceramics.

A susceptor 63 as a lower electrode is provided on the lower surface of the electrostatic chuck 61. The susceptor 63 is formed of a metal such as aluminum into a substantially disc shape. A support base 64 is provided at the bottom of the processing container 68 via an insulating plate 65, and the susceptor 63 is supported on the upper surface of the support base 64. Electrodes (not shown) are provided inside the electrostatic chuck 61, and the wafer W is adsorbed and held on the electrostatic chuck 61 by the electrostatic force generated by applying a DC voltage to the electrode.

The focus ring 62 for improving the uniformity of the plasma processing is made of, for example, conductive silicon, and is arranged on the upper surface of the susceptor 63 and on the outer peripheral portion of the electrostatic chuck 61. The outer surfaces of the susceptor 63 and the support base 64 are covered with a cylindrical member 66 made of, for example, quartz. A coolant passage (not shown) through which a coolant flows is provided inside the support base 64, and the temperature of the wafer W held by the electrostatic chuck 61 is controlled by controlling the temperature of the coolant. It

The power supply unit 80 includes high

frequency power supplies

81 and 83 and matching

units

82 and 84. A high frequency power supply 81 for supplying high frequency power to generate plasma is electrically connected to the susceptor 63 via a matching unit 82. The high frequency power supply 81 is configured to output high frequency power having a frequency of 27 to 100 MHz, for example. Further, the internal impedance of the high frequency power supply 81 and the load impedance are matched by the matching device 82.

Further, the susceptor 63 is electrically connected to a high frequency power source 83 for supplying ions to the wafer W by supplying high frequency power to the susceptor 63 and applying a bias to the wafer W through a matching unit 84. ing. The high frequency power supply 83 is configured to output high frequency power having a frequency of 400 kHz to 13.56 MHz, for example. Like the matching unit 82, the matching unit 84 matches the internal impedance of the high frequency power source 83 and the load impedance. The high

frequency power supplies

81 and 83 and the

matching devices

82 and 84 are connected to the control device 100, and their operations are controlled by the control device 100.

A top plate portion 70 is arranged above the mounting table 60 (upper part of the processing container 68). The top plate portion 70 includes an upper electrode 73 and a gas diffusion chamber 76. Above the susceptor 63, which is a lower electrode, an upper electrode 73 is provided in parallel to face the susceptor 63. The upper electrode 73 is supported on the upper portion of the processing container 68 via the conductive holding member 71. Therefore, the upper electrode 73 is grounded via the holding member 71 and the processing container 68.

The upper electrode 73 is composed of an electrode plate 74 that forms a surface facing the wafer W held by the electrostatic chuck 61, and an electrode support 75 that supports the electrode plate 74 from above. The electrode plate 74 is made of a low-resistance conductor or semiconductor with little Joule heat. The electrode support 75 is made of a conductor. A gas diffusion chamber 76 formed in a substantially disc shape is provided in the central portion inside the electrode support 75. A plurality of gas discharge holes 77 for supplying a processing gas into the processing container 68 are formed in the lower portion of the electrode plate 74 and the electrode support body 75 so as to penetrate through the lower portions of the electrode plate 74 and the electrode support body 75. ing.

A gas supply pipe 78 is connected to the gas diffusion chamber 76. A gas supply source 79 is connected to the gas supply pipe 78 as shown in FIG. 5, and the gas supply source 79 supplies the processing gas to the gas diffusion chamber 76 via the gas supply pipe 78. The processing gas supplied to the gas diffusion chamber 76 is introduced into the processing container 68 through the gas discharge hole 77. The processing gas supplied from the gas supply source 79 contains an inert gas. As the inert gas, a rare gas (for example, argon gas), an ammonia (NH ₃ ) gas, or a nitrogen gas can be used. Of the inert gases, a gas containing no oxygen component may be used.

As an example of the processing gas supplied from the gas supply source 79, a gas containing nitrogen and hydrogen may be used, a gas containing ammonia may be used, or a gas containing nitrogen, hydrogen and ammonia may be used. You may be asked. For example, when a processing gas containing nitrogen and hydrogen is used, the flow rate of the nitrogen component may be 50 mL/min to 500 mL/min and the flow rate of the hydrogen component may be 50 mL/min to 500 mL/min at the reference temperature. In this case, the ratio of the hydrogen component to the nitrogen component may be approximately equal to 1. When the process gas contains hydrogen, nitrogen radicals are likely to be formed (being easily separated from the nitrogen gas or the like). As described above, the plasma processing apparatus 10 uses the plasma of the inert gas as the plasma gas to perform the plasma processing on the coating film of the wafer W. The plasma of the inert gas is a plasma gas obtained by deriving a processing gas containing the inert gas.

An exhaust unit 90 is arranged below the processing container 68. The exhaust unit 90 includes an exhaust port 91, an exhaust chamber 92, an exhaust pipe 93, and an exhaust device 94. An exhaust port 91 is provided on the bottom surface of the processing container 68. An exhaust chamber 92 is formed below the exhaust port 91, and an exhaust device 94 is connected to the exhaust chamber 92 via an exhaust pipe 93. Therefore, by driving the exhaust device 94, the inside of the processing container 68 can be exhausted through the exhaust port 91 and the inside of the processing container can be depressurized to a predetermined vacuum degree.

(Control device)
The controller 100 controls the substrate processing system 1 partially or wholly. The control device 100 is composed of one or a plurality of control computers. For example, the control device 100 includes a circuit including one or more processors, a memory, a storage, a timer, and an input/output port. The storage includes a computer-readable storage medium such as a hard disk. The storage medium stores a program for causing the control device 100 to execute a substrate processing procedure described later. The storage medium may be a removable medium such as a non-volatile semiconductor memory, a magnetic disk or an optical disk. The memory temporarily stores the program loaded from the storage medium of the storage and the calculation result by the processor. The processor executes the above program in cooperation with the memory. The timer measures the elapsed time by counting, for example, a reference pulse having a constant cycle. The input/output port inputs/outputs an electric signal to/from a unit or device to be controlled according to a command from the processor.

[Substrate processing method]
Next, as an example of the substrate processing method, a substrate processing procedure including a procedure for forming an insulating film shown in FIG. 6 will be described. For example, the control device 100 controls the substrate processing system 1 so as to execute the substrate processing including the formation of the insulating film in the following procedure. First, the control device 100 controls the transfer device A1 so as to transfer the wafer W in the carrier C on which the insulating film has not been formed to the shelf unit U10, and arranges this wafer W in the cell for the processing module 11. The transport device A7 is controlled.

Next, the control device 100 controls the transfer device A3 so as to transfer the wafer W of the shelf unit U10 to the coating unit U1 in the processing module 11. Then, the control device 100 controls the coating unit U1 so as to coat the front surface Wa of the wafer W with the polysilazane composition (step S01). In step S01, for example, the control device 100 controls the rotation holding unit 20 to hold the wafer W in the holding unit 23 and rotate the wafer W at a predetermined rotation speed. The rotation speed at this time may be, for example, about 0 rpm to 5000 rpm (for example, 450 rpm to 1000 rpm) at the time of coating and about 50 rpm to 5000 rpm at the time of drying.

In this state, the control device 100 controls the pump 32 and the valve 33 to discharge the polysilazane composition (coating liquid L) from the nozzle 34 onto the front surface Wa of the wafer W. As a result, the coating film AF is formed on the front surface Wa of the wafer W. For example, the control device 100 rotates the wafer W for about 10 seconds to 60 seconds at the above-described number of rotations, and performs control so that the coating film AF having a film thickness of about 10 nm to 1000 nm is formed. Then, the control device 100 controls the transfer device A3 to transfer the wafer W on which the coating film AF of the polysilazane composition is formed to the heat treatment unit U2 in the processing module 11.

Next, the controller 100 controls the heat treatment unit U2 so as to remove the solvent contained in the coating film AF (step S02). In step S02, for example, the controller 100 stores the wafer W in the heat treatment space in the chamber 40, and heats the wafer W for a predetermined time in the air atmosphere or the atmosphere with a small oxygen component (for example, nitrogen atmosphere). The heat treatment unit U2 is controlled as described above. When the wafer W is heated in a nitrogen atmosphere, the controller 100 sets the valve 52 to the open state and controls the heat treatment unit U2 so as to send the nitrogen gas from the gas supply source 53 into the heat treatment space. When heating the wafer W in the air atmosphere, the control device 100 keeps the valve 52 in the closed state.

The controller 100 controls the hot plate 44 so that the temperature is suitable for removing the solvent in the coating film AF by adjusting the current value to the heater 45 in the hot plate 44. The temperature for heating the wafer W (heating temperature) may be about 80° C. to 170° C. (150° C. as an example) in the air atmosphere. The heating temperature may be about 100° C. to 220° C. (200° C. as an example) in a nitrogen atmosphere. The time for heating the wafer W (heating time) may be about 120 seconds to 240 seconds (180 seconds as an example) in the air atmosphere and the nitrogen atmosphere. After a lapse of a predetermined heating time, the control device 100 opens the chamber 40 and removes the solvent in the coating film AF to form a wafer (hereinafter, referred to as “coating film AR”). The support pin 46 (driving unit 47) and the transfer device A3 are controlled so that W is returned to the shelf unit U10. Then, the control device 100 controls the transfer device A1 so that the wafer W is accommodated in the carrier C.

Next, the control device 100 controls the transfer mechanism 19 so as to transfer the wafer W housed in the carrier C and containing the coating film AR to the plasma processing device 10. Then, the control device 100 controls the plasma processing device 10 so that the coating film AR is subjected to plasma processing by plasma of an inert gas (step S03). In step S03, first, the wafer W is placed on the electrostatic chuck 61 so that the coating film AR faces upward. Then, the control device 100 controls the plasma processing device 10 so that an inert gas (for example, a gas containing nitrogen and hydrogen) is supplied from the gas supply source 79 into the processing container 68 as a processing gas for generating plasma. ..

After that, the control device 100 controls the power supply unit 80 so that the high frequency power supply 81 and the high frequency power supply 83 continuously apply the high frequency power to the susceptor 63 which is the lower electrode. As a result, a high frequency electric field is formed between the upper electrode 73 and the electrostatic chuck 61. By forming the high frequency electric field, plasma of the inert gas is generated in the processing container 68, and the coating film AR is subjected to plasma processing by the plasma. The control device 100 maintains the state in which the wafer W is housed in the processing container 68 while generating plasma of an inert gas so that the coating film AR is subjected to plasma processing for a predetermined time. The time for performing the plasma treatment may be, for example, about 30 seconds to 120 seconds (60 seconds as an example).

Next, the control device 100 applies the wafer W including the film (hereinafter, referred to as “coating film AP”) formed by performing the plasma treatment to the coating film AR to the coating/developing device 2 (carrier). The transport mechanism 19 is controlled to transport to block 4). Then, the control device 100 controls the transfer device A1 so as to transfer the wafer W containing the coating film AP in the carrier C to the shelf unit U10, and transfers the wafer W so as to be arranged in the cell for the processing module 11. Control device A7. After that, the control device 100 controls the transfer device A3 to transfer the wafer W containing the coating film AP to the thermal processing unit U2 in the processing module 11.

Next, the control device 100 controls the heat treatment unit U2 in the processing module 11 so that the coating film AP is subjected to the heat treatment (step S04). In step S04, for example, the control device 100 stores the wafer W including the coating film AP in the heat treatment space in the chamber 40, and the wafer W is added to the wafer W under an air atmosphere or an atmosphere with a small oxygen component (for example, a nitrogen atmosphere). The heat treatment unit U2 is controlled to perform heat treatment for a predetermined time. When performing the heat treatment in a nitrogen atmosphere, the control device 100 sets the valve 52 to the open state and controls the heat treatment unit U2 so as to send the nitrogen gas from the gas supply source 53 into the heat treatment space.

The controller 100 controls the hot plate 44 so that the temperature is suitable for the heat treatment of the coating film AP by adjusting the current value to the heater 45 in the hot plate 44. The temperature (heating temperature) for heating the wafer W including the coating film AP may be higher than the heating temperature for removing the solvent in step S02. For example, the heating temperature of the wafer W including the coating film AP may be about 250° C. to 550° C. Alternatively, the heating temperature of the wafer W including the coating film AP may be about 400° C. to 500° C. (450° C. as an example). Further, the time (heating time) for heating the wafer W including the coating film AP may be about 1 minute to 300 minutes.

The insulating film is formed from the coating film AF of the polysilazane composition coated on the wafer W by the series of processes described above. After the elapse of a predetermined heating time, the control device 100 opens the chamber 40, controls the transfer device A3 so as to return the wafer W containing the insulating film to the shelf unit U10, and uses the wafer W for the processing module 12. The transfer device A7 is controlled so that the transfer device A7 is placed in the cell.

Next, the control device 100 controls the transfer device A3 to transfer the wafer W of the shelf unit U10 to the coating unit U1 and the heat treatment unit U2 in the processing module 12. Further, the control device 100 controls the coating unit U1 and the heat treatment unit U2 so as to form a resist film on the insulating coating of the wafer W. After that, the control device 100 controls the transfer device A3 so as to return the wafer W to the shelf unit U10, and further controls the transfer device A7 so as to arrange the wafer W in the cell for the processing module 13.

Next, the control device 100 controls the transfer device A3 so as to transfer the wafer W of the shelf unit U10 to each unit in the processing module 13. Further, the control device 100 controls the coating unit U1 and the heat treatment unit U2 so as to form an upper layer film on the resist film of the wafer W. After that, the control device 100 controls the transfer device A3 so as to transfer the wafer W to the shelf unit U11.

Next, the control device 100 controls the transfer device A8 so that the wafer W accommodated in the shelf unit U11 is sent to the exposure device 3. Then, in the exposure apparatus 3, the resist film formed on the wafer W is exposed. After that, the control device 100 receives the wafer W that has been subjected to the exposure processing from the exposure device 3, and controls the transfer device A8 to arrange the wafer W in the cell for the processing module 14 in the shelf unit U11.

Next, the control device 100 controls the transfer device A3 to transfer the wafer W of the shelf unit U11 to the heat treatment unit U2 in the processing module 14. Then, the control device 100 controls the heat treatment unit U2 so as to subject the resist film of the wafer W to the heat treatment before development. Next, the control device 100 controls the coating unit U1 and the heat treatment unit U2 so that the resist film of the wafer W which has been subjected to the heat treatment before the development by the heat treatment unit U2 is subjected to the development treatment and the heat treatment after the development treatment. After that, the control device 100 controls the transfer device A3 to return the wafer W to the shelf unit U10, and controls the transfer devices A7 and A1 to return the wafer W into the carrier C. This completes the substrate processing procedure including the formation of the insulating coating.

[Results of component analysis]
Next, the analysis results of the components contained in the insulating film formed by the above substrate processing method will be described.

(FT-IR)
In order to obtain the insulating coating to be analyzed, a compound composed of —(SiH ₂ NH)— as a basic unit was used as the polysilazane compound contained in the polysilazane composition applied in step S01. In addition, dibutyl ether was used as the solvent contained in the polysilazane composition. By applying the above polysilazane composition to a Si substrate, a coating film AF having a film thickness of about 50 nm was formed on the substrate. In the heat treatment in step S02, the heating temperature was set to 200° C. and the heating time was set to 180 seconds in a nitrogen atmosphere. In the plasma processing in step S03, a plasma processing was performed for 60 seconds using a gas containing hydrogen as a nitrogen gas as a processing gas for generating plasma of an inert gas. In the heat treatment in step S04, the heat treatment temperature was set to 450° C. in a nitrogen atmosphere. In addition, the thing which formed the insulating film for comparison on the board|substrate by the same procedure as the above except not performing the heat processing of step S04 was prepared.

Infrared absorption spectra relating to the analysis results of the insulating coating by Fourier transform infrared spectroscopy (FT-IR) are shown in FIG. 7A, FIG. 7B, FIG. 8A, and FIG. It shows in (b). In this analysis, in order to evaluate the effect of the plasma treatment, the insulating coatings (for comparison) obtained with the plasma treatment and without the plasma treatment were analyzed. FIG. 7A and FIG. 8A show analysis results when the plasma treatment is not performed. FIG. 7B and FIG. 8B show the analysis results when the plasma treatment is performed. In FIGS. 7 (a) and 7 (b), the wave number, respectively show the infrared absorption spectrum in the range is ^4000cm ^-1 ~ 1500cm -1. Further, in FIG. 8 (a) and FIG. 8 (b), the wave number respectively show the infrared absorption spectrum in the range is ^1500cm ^-1 ~ 400cm -1. The vertical axis shows the absorbance. In addition, in these analysis results, the result in the case where the heat treatment in step S04 is not performed is shown as "no heat treatment". In addition, the results when the heat treatment time (heating time) in step S04 is 3 minutes, 10 minutes, and 150 minutes are shown as “3 min”, “10 min”, and “150 min”.

"Si-H" in the membrane of the analyte (silicon - hydrogen) if the bond is included, increase in absorbance in the vicinity of a wave number of ^{2200 cm} -1 ~ 2100 cm ^-1 (peak) appears. From the results of comparison between FIG. 7A and FIG. 7B, it can be seen that “Si—H” bonds in the film are reduced by performing the plasma treatment in step S03.

When the film to be analyzed contains a “Si—O” (silicon-oxygen) bond, an increase in absorbance (peak) appears near the wave number of 1000 cm ⁻¹ to 900 cm ⁻¹ . Also, "Si-N" to the analyte in the membrane (silicon - nitrogen) When a bond is included, increase in absorbance in the vicinity of a wave number of ^{900 cm} -1 ~ 800 cm ^-1 (peak) appears. From the result of comparison between FIG. 8A and FIG. 8B (particularly, the result of comparison between 150 min), the fluctuation of the “Si—N” bond in the film can be confirmed by performing the plasma treatment in step S03. It can be seen that the number of “Si—O” bonds in the film is reduced, though it is small.

As described above, it is understood that the plasma treatment reduces the “Si—H” bonds and the “Si—O” bonds and relatively increases the “Si—N” bonds in the film. It should be noted that the increase in the absorbance at a wave number of around 1100 cm ⁻¹ in FIGS. 8A and 8B is considered to be due to the components of the natural oxide film of silicon existing in the wafer W in advance.

(XPS)
FIG. 9A, FIG. 9B, FIG. 10A, and FIG. 10B show analysis results (component ratios) of components in the film by X-ray photoelectron spectroscopy (XPS). Shown in. The conditions of various treatments for forming the insulating coating to be analyzed by X-ray photoelectron spectroscopy were the same as those for the analysis by Fourier transform infrared spectroscopy, and the heat treatment time in step S04 was 150 minutes. 9(a) and 9(b) show the analysis results when the plasma treatment of step S03 was not performed. Further, FIGS. 10A and 10B show the analysis results when the plasma treatment of step S03 is performed. The analysis result of FIG. 9A is the component ratio in the film after the processing of steps S01 and S02 is performed, and the analysis result of FIG. 9B is the processing of steps S01, S02, and S04. Is the ratio of components in the film after That is, FIG. 9A and FIG. 9B show the change of the component by performing step S04. The analysis result of FIG. 10A is the component ratio in the film after the processing of steps S01 to S03 is performed, and the analysis result of FIG. 10B is the processing of steps S01 to S04. It is the component ratio in the film afterward. That is, FIG. 10A and FIG. 10B show changes in the components due to performing step S04. In these analysis results, the horizontal axis represents the sputtering time (minutes) according to the depth of the wafer W including the film (distance from the surface of the wafer W), and the vertical axis represents each component (element). The ratio (%) is shown. In each analysis result, when the sputtering time exceeds about 5 minutes, the Si component ratio approaches 100%, but the portion where the Si component ratio is 100% is the Si substrate existing under the film. Is shown (a part which is not a film).

From the analysis result of FIG. 9A, the component ratio in the film subjected to the processing of steps S01 and S02 is represented by formula (1). Further, based on the analysis result of FIG. 9B, the component ratio in the film subjected to the processing of steps S01, S02, and S04 is expressed by equation (2). From the results of the equations (1) and (2), when the plasma treatment is not performed, the insulating coating is in the oxygen rich state (more oxygen than other components) after the heat treatment.
Si:N:O=0.5:0.3:0.2 (1)
Si:N:O=0.4:0.15:0.45 (2)

From the analysis result of FIG. 10A, the component ratio in the film in which steps S01 to S03 have been performed is represented by formula (3). Further, from the analysis result of FIG. 10B, the component ratio in the film subjected to the processing of steps S01 to S04 is represented by the equation (4). From the results of the equations (3) and (4), when the plasma treatment is performed, the insulating coating is maintained in a nitrogen-rich state (there is more nitrogen than oxygen except for silicon) after the heat treatment. .. Further, it can be seen from these analysis results that the proportion of nitrogen in the case of performing the plasma treatment is higher than that in the case of not performing the plasma treatment (equation (2)).
Si:N:O=0.53:0.4:0.07 (3)
Si:N:O=0.53:0.4:0.07 (4)

(RBS+HFS)
Next, the analysis results of the component ratios (number ratio of elements) of Si, N, O, and H using Rutherford Backscattering Spectrometry (RBS) and Hydrogen Forward Scattering (HFS) will be explained. To do. An insulating coating to be analyzed was formed on the substrate under the same conditions as the analysis by Fourier transform infrared spectroscopy except for the heat treatment in step S02. However, the RBS and HFS analyzes were performed on the coating film (the film corresponding to the coating film AP described above) before the heat treatment in step S04. In the heat treatment in step S02, the heating temperature was set to 150° C. and the heating time was 180 seconds in the air atmosphere. Table 1 shows the composition ratio (number ratio of elements) of silicon, nitrogen, oxygen, and hydrogen in the polysilazane compound as the comparison target, and the insulating coating after the plasma processing (after the processing of steps S01 to S03) as the analysis target. 3 shows the component ratio (element number ratio) of each element in FIG. The component ratio of each element in the polysilazane compound is obtained from the chemical formula of the polysilazane compound contained in the polysilazane composition used for forming the coating film. From the results in Table 1, it can be seen that the proportion of hydrogen is reduced by performing the plasma treatment. That is, it is estimated that a part of hydrogen in the coating film is lost by performing the plasma treatment. Further, it can be seen that the proportion of oxygen in the coating film does not change much depending on the presence or absence of plasma treatment.

[Action]
In the substrate processing method according to the above-described embodiment, the polysilazane composition is applied to the wafer W to form the coating film AF, the solvent in the coating film AF is removed, and the coating film with the solvent removed ( The coating film AR) is subjected to plasma treatment with plasma of an inert gas, and heat treatment of the plasma-treated coating film (coating film AP) is included. That is, in the substrate processing method according to the above-described embodiment, the film containing the polysilazane compound formed by applying the polysilazane composition to the substrate is subjected to plasma processing using plasma of an inert gas.

In the insulating coating formed by this substrate processing method, the quality of the insulating film formed by the polysilazane composition can be improved by performing the plasma treatment with the plasma of the inert gas as compared with the case where the plasma treatment is not performed. it can. Specifically, the insulating coating obtained through the plasma treatment has a high refractive index and an improved etching resistance.

With the above substrate processing method, it is possible to achieve the same quality (refractive index and etching rate) as a silicon nitride film formed by CVD (chemical vapor deposition). This is because when the coating film of the polysilazane composition is subjected to the plasma treatment, the “Si—H” bond and the “N—H” bond contained in the polysilazane compound are broken, and Si and N are separated from each other. It is speculated that the crosslinking reaction proceeds and the number of “Si—N” bonds increases. The occurrence of these phenomena is expected from the results of component analysis in the film shown in FIGS. 7 to 10. In addition, the hydrogen element in the insulating film is reduced and the “Si—N” bond is increased, so that the portion where the interatomic distance between Si and N in the film is reduced is increased, so that the density of the insulating film is high. Expected to be. As a result, it is considered that the refractive index of the insulating coating is increased and the etching resistance is improved.

Conventionally, the silicon nitride film is often formed by using CVD from the viewpoint of quality. Since the above-described substrate processing method can obtain a silicon nitride film having a quality similar to that of the silicon nitride film formed by CVD, it may be replaced with a method of forming a silicon nitride film from a coating solution of a polysilazane composition instead of CVD. It will be possible. Since the processing time from the coating film of the polysilazane composition to the formation of the insulating film can be shorter than the time required for the film formation by CVD, the substrate processing throughput can be improved by replacing CVD with the present substrate processing method. It is possible to improve.

In forming a silicon nitride film by CVD, the film formation temperature is generally about 500°C to 800°C. When the heat treatment is performed at a high temperature (for example, 600° C. or higher), there is a concern that cost may increase and throughput may decrease. Further, from the viewpoint of various wirings formed on the wafer W and the quality of the semiconductor region, it may be necessary to avoid the heat treatment at a high temperature and perform the heat treatment at a low temperature. In the substrate processing method described above, the plasma-treated coating film is heat-treated at a relatively low temperature of 550° C. or lower. In the substrate processing method according to the above embodiment, the quality of the silicon nitride film is improved by performing the plasma treatment regardless of whether the heat treatment is performed at a low temperature or not.

In the above embodiment, the heat treatment unit U2 heats the wafer W including the coating film AF, whereby the solvent in the coating film AF is removed. In this case, the unit that performs the heat treatment and the solvent removal in step S04 can be shared, and the substrate processing system 1 can be simplified.

In the above embodiments, the heat treatment unit U2 heats the coating film AF in a nitrogen atmosphere, so that the solvent in the coating film AF is removed. In this case, the formation of an oxide film on the surface of the coating film AF is suppressed as compared with the case where heating for removing the solvent is performed in the air atmosphere, so that the quality as an insulating coating is improved.

In the above embodiment, the inert gas used for the plasma treatment is a gas containing nitrogen. The plasma treatment increases the refractive index of the insulating coating, but may reduce the film thickness. On the other hand, by using the plasma of the inert gas containing nitrogen, the reduction of the film thickness is suppressed, so that both the securing of the film thickness and the increase of the refractive index of the insulating coating can be achieved.

In the above embodiment, the processing gas used to generate the plasma of nitrogen gas contains hydrogen. In this case, since the nitrogen gas is turned into plasma by hydrogen, it is possible to perform the plasma treatment more efficiently. In addition, the refractive index may be higher than that when plasma treatment is performed using nitrogen gas plasma in the case of not containing hydrogen.

[Example]
The above embodiments will be specifically described below with reference to Examples, but the scope of the present disclosure is not limited thereto.

(Examples 1 to 4)
Using the substrate processing system 1 according to the above embodiment, the insulating coatings according to Examples 1 to 4 were formed by the following procedure. First, in the coating unit U1 of the processing module 11, the polysilazane composition (coating liquid L) was supplied to the front surface Wa of the wafer W to form the coating film AF. At this time, the wafer W was rotated at 1000 rpm for 20 seconds to form a coating film AF having a film thickness of 50 nm. In order to obtain the insulating coatings of Examples 1 to 4, as the polysilazane compound contained in the polysilazane composition, a compound composed of —(SiH ₂ NH)— as a basic unit was used. In addition, dibutyl ether was used as the solvent contained in the polysilazane composition.

Next, in the heat treatment unit U2 of the processing module 11, the wafer W was heated in the atmosphere to remove the solvent in the coating film AF. At this time, the heating temperature (the temperature of the heating plate 44) was set to 150° C., and the coating film AF was heated for 180 seconds to form the coating film AR (the coating film from which the solvent was removed). Next, in the plasma processing apparatus 10, the coating film AR was subjected to plasma processing. At this time, a plasma of nitrogen gas is generated using a processing gas containing nitrogen and hydrogen, and the wafer W is held in the plasma processing apparatus 10 (processing container 68) in a state where the plasma is generated for 60 seconds, whereby the coating film is formed. AP (coating film subjected to plasma treatment) was formed. The insulating coating according to Example 1 was obtained by the above procedure.

Further, in the heat treatment unit U2 of the processing module 11, the heat treatment is performed on the wafer W on which the coating film AP corresponding to the first embodiment is formed in a nitrogen atmosphere to form the insulating coatings according to the second to fourth embodiments. did. Specifically, the insulating film of Example 2 was obtained by performing a heat treatment for 3 minutes on the coating film AP. Further, the insulating film of Example 3 was obtained by performing heat treatment on the coating film AP for 10 minutes. Further, the coating film AP was heat-treated for 150 minutes to obtain an insulating coating film of Example 4.

(Examples 5 to 8)
The insulating coating according to Example 5 was formed in the same manner as the insulating coating according to Example 1, except that the wafer W was heated in the nitrogen atmosphere in the heat treatment unit U2 of the processing module 11. When the wafer W was heated to remove the solvent, the heating temperature (temperature of the heating plate 44) was set to 200° C., and the coating film AF was heated for 180 seconds. As a result, the insulating coating according to Example 5 was obtained.

Further, similar to the second to fourth embodiments, the heat treatment is performed on the wafer W on which the coating film AP corresponding to the fifth embodiment is formed in the heat treatment unit U2 of the processing module 11 in the nitrogen atmosphere, thereby performing the heat treatment. An insulating film according to Nos. 6 to 8 was formed. That is, specifically, the insulating film of Example 6 was obtained by performing a heat treatment for 3 minutes on the coating film AP. Further, the insulating film of Example 7 was obtained by performing heat treatment on the coating film AP for 10 minutes. Further, the coating film AP was heat-treated for 150 minutes to obtain an insulating coating of Example 8.

(Comparative Examples 1 to 4)
An insulating coating film according to Comparative Example 1 was formed in the same manner as the insulating coating film according to Example 1 except that the plasma treatment was not performed on the coating film AR. In addition, as in Examples 2 to 4, in the thermal processing unit U2 of the processing module 11, the wafer W on which the coating film AP corresponding to Comparative Example 1 was formed was heated in a nitrogen atmosphere, so that the Comparative Example An insulating film according to Nos. 2 to 4 was formed. The heat treatment times for the coating film AP when forming the insulating coatings of Comparative Examples 2 to 4 were 3 minutes, 10 minutes, and 150 minutes, respectively.

(Comparative Examples 5-8)
An insulating coating film according to Comparative Example 5 was formed in the same manner as the insulating coating film according to Example 5 except that the plasma treatment was not performed on the coating film AR. In addition, as in Examples 6 to 8, in the heat treatment unit U2 of the processing module 11, the wafer W on which the coating film AP corresponding to Comparative Example 5 was formed was subjected to the heat treatment in the nitrogen atmosphere, and thus the Comparative Example An insulating film according to Nos. 6 to 8 was formed. The heat treatment times for the coating film AP when forming the insulating coatings of Comparative Examples 6 to 8 were 3 minutes, 10 minutes, and 150 minutes, respectively.

(Reference examples 1 and 2)
As the insulating film according to Reference Example 1, a silicon nitride film was formed by CVD. When forming the insulating coating of Reference Example 1, DCS (dichlorosilane) and ammonia were used as raw material gases. The thickness of the insulating coating film of Reference Example 1 was set to 50 nm. Further, instead of the plasma treatment in forming the insulating coating of Example 4, the coating film AR (the coating film from which the solvent has been removed) is irradiated with ultraviolet rays (UV) having an energy of 10000 mJ in the depressurized processing space. Thus, the insulating coating film according to Reference Example 2 was formed.

Table 2 shows the conditions for forming the insulating coating according to the above-mentioned examples, comparative examples, and reference examples.

(Measurement result of film thickness)
The film thickness [nm] of each of the insulating coatings of Examples 1, 4, 5, 8 and Comparative Examples 1, 4, 5, 8 was measured. The film thickness was measured by a spectroscopic ellipsometry method using a film measuring device (model Aleris8350; manufactured by KLA Tencor). Further, a substantially central position of the insulating coating in a top view was selected as a measurement location, and the film thickness at the measurement location was measured. FIG. 11 shows the measurement results of these film thicknesses. From the measurement result of FIG. 11, it was confirmed that the film thickness was reduced by the plasma treatment regardless of the presence or absence of the heat treatment after the plasma treatment.

(Results of refractive index measurement)
The refractive index of each of the insulating coatings of Examples 1, 4, 5, 8 and Comparative Examples 1, 4, 5, 8 and Reference Examples 1, 2 was measured. As the refractive index, the refractive index for light with a wavelength of 633 nm was measured. The refractive index was measured by a spectroscopic ellipsometry method using a film measuring device (type Aleris8350; manufactured by KLA Tencor). Further, a substantially central position of the insulating coating in a top view was selected as a measurement location, and the refractive index at the measurement location was measured. Utilizing the tendency that the refractive index increases as the density of the insulating coating increases, the density of the insulating coating is evaluated using the refractive index as an index.

FIG. 12 shows the measurement results of the refractive indexes of the insulating coatings of Examples 1, 4, 5, 8 and Comparative Examples 1, 4, 5, 8 and Reference Examples 1 and 2. From the measurement results of FIG. 12, whether the plasma treatment is performed in comparison with the case where the plasma treatment is not performed regardless of whether the wafer W is heated in the air atmosphere or the nitrogen atmosphere when the wafer W is heated to remove the solvent. It was confirmed that the refractive index was increased in the case. That is, it was confirmed that the density of the insulating coating was improved when the plasma treatment was performed. Furthermore, it was confirmed that when the plasma treatment was performed, an insulating coating film having a refractive index similar to that of the silicon nitride film (Reference Example 1) formed by CVD was obtained. On the other hand, in the case of irradiating with ultraviolet rays instead of the plasma treatment (Reference Example 2), the same degree of refractive index as in the case of performing film formation by CVD (when performing plasma treatment) may not be obtained. confirmed. It was confirmed that the refractive index is slightly higher when the heating condition for removing the solvent in step S02 (atmosphere in the heating space) is nitrogen than when it is the atmosphere.

(Measurement result of the density of the insulating film)
FIG. 13 shows the measurement results of the density (film density) [g/cm ³ ] of the insulating film using the X-ray reflectance method (XRR: X-Ray Reflectometry). “PSZ→Bake→N ₂ H ₂ Plasma” in FIG. 13 indicates the analysis result of the film density of the coating film AP (coating film subjected to the plasma treatment) formed by performing the processing of steps S01 to S03. ing. “PSZ→Bake” indicates the analysis result of the film density of the coating film AR (coating film from which the solvent has been removed) formed by performing the processing of steps S01 and S02. When forming the film to be analyzed, the thickness of the coating film AP was set to 50 nm, and the heat treatment in step S02 was performed at a heating temperature of 150° C. for 180 seconds in the air atmosphere. Further, in the plasma processing in step S03, a processing gas containing nitrogen and hydrogen was used. The film density of the coating film AR is 1.44 in almost the entire thickness direction of the film, whereas the film density of the coating film AP is 2.47, 2.34 in order from the surface (0 nm). It was 1.95 and 1.63, which were confirmed to be higher than the film density of the coating film AR.

(Measurement result of etching rate)
The etching rates of the insulating coatings of Examples 1 to 8, Comparative Examples 1 to 8 and Reference Examples 1 and 2 were measured. Specifically, when etching is performed using a gas containing octafluorocyclobutane (C ₄ F ₈ ), argon (Ar), and oxygen (O ₂ ), a film composed of SiO ₂ (silicon oxide film) The ratio of the etching amount of the insulating film to the etching amount of the above) was calculated as an etching rate and evaluated. It is shown that the lower the etching rate, the more difficult the insulating coating is to be etched (higher etching resistance) during the etching of the silicon oxide film.

FIG. 14 shows the etching rate evaluation results for the insulating coatings of Examples 1 to 4, Comparative Examples 1 to 4, and Reference Examples 1 and 2. FIG. 15 shows the etching rate evaluation results for the insulating coatings of Examples 5 to 8, Comparative Examples 5 to 8 and Reference Examples 1 and 2. From the evaluation results of FIGS. 14 and 15, it can be seen that the insulating coatings of Comparative Examples 1 to 8 have almost the same etching resistance as the silicon oxide film. That is, it is understood that the insulating coatings of Comparative Examples 1 to 8 are substantially silicon oxide films. On the other hand, the insulating coatings of Examples 1 to 4 have a lower etching rate than the insulating coatings of Comparative Examples 1 to 4, and the insulating coatings of Examples 5 to 8 are more etched than the insulating coatings of Comparative Examples 5 to 8. You can see that the rate is low. That is, it was confirmed that the insulating coatings of Examples 1 to 8 (insulating coatings subjected to plasma treatment) had improved etching resistance as compared with insulating coatings not subjected to plasma treatment.

Also, it was confirmed that the insulating coatings of Examples 1 to 8 (in particular, Examples 4 and 8) could obtain an etching rate comparable to that of the insulating coating formed by CVD. On the other hand, it was confirmed that when the ultraviolet irradiation was performed instead of the plasma treatment (the insulating coating of Reference Example 2), the same etching rate as when the film was formed by CVD was not obtained. In addition, it was confirmed that the etching rate evaluation result under the present conditions did not largely depend on the heating condition (atmosphere of the heating space) for removing the solvent in step S02.

(Measurement results of film thickness and refractive index when the type of processing gas is changed)
The film thickness and the refractive index of the insulating film were measured by changing the type of processing gas in plasma processing (hereinafter referred to as "type of plasma"). 16(a) and 16(b) show the measurement results of the film thickness and the refractive index when the type of plasma is changed. As the type of plasma, measurement using a processing gas containing nitrogen and hydrogen represented by “N ₂ H ₂ ”, a gas containing argon represented by “Ar”, and a gas containing nitrogen represented by “N ₂ ”is performed. went. The ratios of nitrogen and hydrogen contained in the processing gas containing nitrogen and hydrogen were set to the same level. “Wo_Tre” indicates the measurement result when the plasma treatment is not performed. The processing is performed under the same conditions except for the type of plasma.

From the measurement result of FIG. 16A, it was confirmed that the film thickness was further reduced when the gas containing argon was used, as compared with the gas containing nitrogen and the gas containing nitrogen and hydrogen. From the measurement result of FIG. 16B, it was confirmed that the refractive index was higher (the density was higher) regardless of the type of plasma as compared with the case where the plasma treatment was not performed. It was also confirmed that the refractive index was higher when a gas containing nitrogen and hydrogen or a gas containing argon was used, as compared with a gas containing nitrogen.

[Modification]
The embodiments disclosed above are to be considered in all respects as illustrative and not restrictive. The above-described embodiments may be omitted, replaced, or modified in various forms without departing from the scope and spirit of the appended claims.

The specific configuration of the substrate processing system is not limited to the configuration of the substrate processing system 1 illustrated above. The substrate processing system includes a coating unit for coating the substrate with the polysilazane composition, a unit for removing the solvent in the coating film, a plasma processing apparatus for performing plasma processing on the coating film from which the solvent has been removed, and a plasma processing unit. Any unit may be used as long as it has a heat treatment unit for heat-treating the coating film. For example, the plasma processing apparatus 10 may be provided in the coating/developing apparatus 2. Specifically, the plasma processing apparatus 10 may be provided in the processing module 11 or the interface block 6.

[Another example of plasma processing apparatus]
The substrate processing system 1 may include a plasma processing apparatus 10A shown in FIG. 17 instead of the plasma processing apparatus 10. The plasma processing apparatus 10A is different from the plasma processing apparatus 10 in that the number of wafers W that can be plasma-processed at substantially the same timing, a method of generating plasma gas, and that heat treatment can be performed in parallel with the plasma processing. .. As shown in FIG. 17, the plasma processing apparatus 10A includes a wafer boat 110, a processing container 120, a plasma gas supply unit 130 (plasma processing unit), a heating gas supply unit 160 (heat treatment unit), and an exhaust unit 170. Have and. Each element of the plasma processing apparatus 10A is controlled by the control device 100.

The wafer boat 110 holds a plurality of wafers W. The wafer boat 110 is configured so that, for example, about 20 to 150 wafers W can be placed. The wafer boat 110 holds the plurality of wafers W in a state where the front surfaces Wa of the plurality of wafers W are horizontal and arranged in the vertical direction with a space provided therebetween. The wafer boat 110 is made of a metal material such as aluminum.

The processing container 120 accommodates the wafer boat 110 that holds a plurality of wafers W. The processing container 120 forms a processing space for performing plasma processing by the plasma processing apparatus 10A. The processing container 120 is formed, for example, so as to extend in the vertical direction and has a cylindrical shape. An opening for loading and unloading the wafer boat 110 may be formed at the lower end of the processing container 120, and a lid that can be opened and closed may be provided at the opening. The processing container 120 is made of a metal material such as aluminum. The processing container 120 is grounded via a ground wire.

The plasma gas supply unit 130 generates plasma gas and supplies the plasma gas to the processing space in the processing container 120. Since the plasma film is supplied to the processing space to perform the plasma processing on the coating film of each wafer W, the plasma gas supply unit 130 performs the plasma processing on the coating film of the wafer W. Function as. The plasma gas supply unit 130 has a rectification unit 140 and a plasma gas generation unit 150. The rectification unit 140 supplies the plasma gas generated by the plasma gas generation unit 150 to the processing space inside the processing container 120.

The rectification unit 140 includes an expansion unit 141 and a plurality of rectification plates 142. The expansion part 141 is provided on one side wall of the processing container 120 and is formed so as to project outward from the side wall. The vertical length of the expansion portion 141 is set so as to cover substantially the entire vertical length of the wafer boat 110. The plurality of straightening vanes 142 are provided in the opening formed in the sidewall of the processing container 120. Each of the plurality of rectifying plates 142 is horizontally arranged, and the plurality of rectifying plates 142 rectifies the flow of the plasma gas in the expansion portion 141 into a laminar flow state to supply the plasma gas into the processing container 120. To be done.

The plasma gas generation unit 150 includes a pipe 151, a microwave generation source 152, and a gas introduction unit 153. One end of the pipe 151 is connected to the space inside the expansion section 141 via a gas hole 154 provided on the outer wall of the expansion section 141. The microwave generation source 152 is connected in the middle of the pipe 151 via the waveguide 155. The gas introduction unit 153 is connected to the other end of the pipe 151 and is configured to be able to be introduced into the pipe 151 while controlling the flow rate of the processing gas. The processing gas introduced into the pipe 151 is converted into plasma by the microwaves from the microwave generation source 152, and the generated plasma gas is supplied into the expanded portion 141 through the gas holes 154.

The frequency of the microwave generated by the microwave generation source 152 is, for example, 2.45 GHz, but is not limited to this, and another frequency, for example, 400 MHz may be used. As with the plasma processing apparatus 10, a gas containing an inert gas may be used as the processing gas.

The heating gas supply unit 160 supplies the heated gas to the processing space inside the processing container 120. Since the heated gas is supplied to the processing space in the processing container 120 to heat the coating film of each wafer W, the heating gas supply unit 160 functions as a heat treatment unit that heat-treats the coating film of the wafer W. .. The heating gas supply unit 160 supplies, for example, a heated inert gas to the processing space in the processing container 120. As the inert gas supplied by the heating gas supply unit 160, for example, nitrogen gas is used.

The heating gas supply unit 160 has a dispersion nozzle 161, a gas heater 162, and a gas passage 163. The dispersion nozzle 161 is formed so as to extend in the vertical direction, and is arranged inside the processing container 120 with respect to the flow regulating plate 142. A gas passage 163 having a gas heater 162 provided in the middle thereof is connected to the dispersion nozzle 161. The gas heater 162 heats the inert gas from the gas supply source and supplies the heated inert gas to the dispersion nozzle 161. The gas heater 162 heats the inert gas to 400° C. to 1000° C., for example. The gas heater 162 may heat the inert gas to 450° C. to 850° C., or may heat the inert gas to 500° C. to 800° C. A plurality of gas holes 161A are formed in the dispersion nozzle 161 at predetermined intervals. By horizontally injecting the inert gas through the plurality of gas holes 161A, the dispersion nozzle 161 supplies the inert gas toward the center of the processing container 120.

The exhaust unit 170 discharges the gas in the processing space inside the processing container 120 to the outside. For example, the evacuation unit 170 evacuates the inside of the processing container 120 through an exhaust port formed on the outer wall of the processing container 120 facing the expanded portion 141, and the processing space in the processing container 120 is evacuated to a predetermined vacuum pressure. It is designed to be maintained.

In the plasma processing apparatus 10A described above, the plasma processing apparatus 10 performs the plasma processing on the coating film of one wafer W, whereas the plasma processing apparatus 10 performs plasma processing on the coating film of each of the plurality of wafers W at substantially the same timing. It is possible to perform processing. Further, in the plasma processing apparatus 10A, the plasma processing apparatus 10 generates the plasma gas in the processing space by the pair of electrodes sandwiching the wafer W, whereas the plasma processing apparatus 10A generates the plasma gas in a place different from the processing space. The generated plasma gas is supplied to the processing space.

Also in the substrate processing method in the substrate processing system 1 including the plasma processing apparatus 10A, steps S01 to S04 shown in FIG. 6 may be executed. Since the plasma processing apparatus 10A can perform the heat treatment and the plasma treatment, the plasma processing in step S03 and the heat treatment in step S04 may be performed in the plasma processing apparatus 10A. Since the plasma processing apparatus 10A can perform the thermal processing and the plasma processing in parallel, the control apparatus 100 causes the plasma processing apparatus 10A to perform the thermal processing of step S04 in a period overlapping at least a part of the execution period of step S03. It may be executed. For example, the control device 100 may heat the coating film by supplying the heated gas to the heating gas supply unit 160 during a period that overlaps with at least a part of the execution period of the plasma processing by the plasma gas supply unit 130. Good.

Even when the plasma treatment of step S03 and the heat treatment of step S04 are performed at timings at least partially overlapping with each other, the plasma treatment of the coating film is performed while the plasma treatment of the coating film proceeds, so that the plasma treatment is performed. A heat treatment is performed on the applied coating film. Thus, heat-treating the plasma-treated coating film includes heating the coating film in a period that overlaps with at least a part of the plasma treatment execution period for the solvent-free coating film. Be done. The control device 100 performs plasma treatment on the coating film by the plasma gas supply unit 130, stops the supply of the plasma gas from the plasma gas supply unit 130, and then heats the coating film by the heating gas supply unit 160. May be.

In the substrate processing method executed in the substrate processing system 1 including the plasma processing apparatus 10A illustrated above, heat treatment of the plasma-treated coating film (coating film AP) is performed by removing the solvent from the coating film (coating film AP). Heating the coating film during a period that overlaps at least part of the execution period of the plasma treatment on the coating film AR). Also in this case, the quality of the insulating coating can be improved. Further, since the execution periods of the plasma treatment and the heat treatment overlap at least partially, the throughput can be improved. By performing the plasma treatment, it is possible to accelerate the crosslinking reaction by heating by heat treatment while cutting the “Si—H” bond and the “N—H” bond contained in the polysilazane compound. Therefore, the silicon nitride film can be formed more efficiently.

In the plasma processing apparatus 10, since the plasma gas is generated while the wafer W is sandwiched between the pair of electrodes, it is possible to cause the coating film on the wafer W to react with the accelerated ions. Therefore, plasma processing can be performed at a lower temperature than that of the plasma processing apparatus 10A. On the other hand, in the plasma processing apparatus 10A, since plasma is generated in a region different from the processing space, the type of processing gas for generating plasma is not limited as compared with the plasma processing apparatus 10. From the above, either the plasma processing apparatus 10 or the plasma processing apparatus 10A may be selected depending on the heatable temperature at the stage of forming the insulating coating.

[Example]
Next, with reference to FIGS. 18 to 20, an embodiment including the case where the plasma processing apparatus 10A is used will be described.

(Example 9)
Using the substrate processing system 1 including the plasma processing apparatus 10, the insulating coating according to Example 9 was formed by the following procedure. First, in the coating unit U1 of the processing module 11, the polysilazane composition (coating liquid L) was supplied to the front surface Wa of the wafer W to form the coating film AF. At this time, the wafer W was rotated at 1000 rpm for 20 seconds to form a coating film AF having a film thickness of 45 nm. In order to obtain the insulating coatings of Examples 9 and 10, as the polysilazane compound contained in the polysilazane composition, a compound composed of —(SiH ₂ NH)— as a basic unit was used. In addition, dibutyl ether was used as the solvent contained in the polysilazane composition.

Next, in the heat treatment unit U2 of the processing module 11, the wafer W was heated in the atmosphere to remove the solvent in the coating film AF. At this time, the heating temperature (the temperature of the heating plate 44) was set to 150° C., and the coating film AF was heated for 180 seconds to form the coating film AR (the coating film from which the solvent was removed). Next, in the plasma processing apparatus 10, the coating film AR was subjected to plasma processing. At this time, a plasma of nitrogen gas is generated using a processing gas containing nitrogen and hydrogen, and the wafer W is held in the plasma processing apparatus 10 (processing container 68) in a state where the plasma is generated for 60 seconds, whereby the coating film is formed. AP (coating film subjected to plasma treatment) was formed. The insulating coating according to Example 9 was obtained by the above procedure.

(Example 10)
Further, in the heat treatment unit U2 of the processing module 11, the wafer W on which the coating film AP corresponding to Example 9 was formed was subjected to heat treatment to form the insulating coating according to Example 10. Specifically, the coating film AP was heat-treated at a temperature of 450° C. for 150 minutes in a nitrogen atmosphere to obtain an insulating coating film of Example 10.

(Example 11)
Using the substrate processing system 1 including the plasma processing apparatus 10A, the insulating coating according to Example 11 was formed by the following procedure. First, in the coating unit U1 of the processing module 11, the polysilazane composition (coating liquid L) was supplied to the front surface Wa of the wafer W to form the coating film AF. At this time, the wafer W was rotated at a rotation speed of 1000 rpm for 20 seconds to form a coating film AF having a film thickness of 48 nm. In order to obtain the insulating coating film of Example 11, a compound composed of —(SiH ₂ NH)— as a basic unit was used as the polysilazane compound contained in the polysilazane composition. In addition, dibutyl ether was used as the solvent contained in the polysilazane composition.

Next, in the heat treatment unit U2 of the processing module 11, the wafer W was heated in the atmosphere to remove the solvent in the coating film AF. At this time, the heating temperature (the temperature of the heating plate 44) was set to 150° C., and the coating film AF was heated for 180 seconds to form the coating film AR (the coating film from which the solvent was removed). Next, in the plasma processing apparatus 10A, the plasma-treated coating film was heated while the plasma treatment was performed on the coating film AR. At this time, in the plasma processing apparatus 10A, a plasma gas was generated using a processing gas containing ammonia, and the plasma gas was supplied into the processing container 120. In addition to the plasma gas, nitrogen gas heated to 630° C. was supplied into the processing container 120. By holding the wafer W in the processing container 120 for 600 seconds, a coating film subjected to plasma processing and heat treatment was formed. The insulating coating according to Example 11 was obtained by the above procedure.

(Example 12)
In the plasma processing apparatus 10A, a plasma gas was generated using a processing gas containing hydrogen and nitrogen, and the plasma gas was supplied into the processing container 120. The insulating coating according to the above was formed.

(Comparative Example 9)
In the plasma processing apparatus 10A, the insulation according to Comparative Example 9 was performed in the same manner as the insulation coating according to Example 11 except that the nitrogen gas heated to 630° C. was supplied into the processing container 120 without supplying the plasma gas. A film was formed.

(Measurement result of film thickness)
The film thickness [nm] of each of the insulating coatings of Examples 9 to 12 was measured. The film thickness [nm] of the coating film before the removal of the solvent for forming the insulating coating, the plasma treatment, and the heat treatment (hereinafter, referred to as “pre-treatment coating film”) was also measured. The film thickness was measured by a spectroscopic ellipsometry method using a film measuring device (model Aleris8350; manufactured by KLA Tencor). Further, a substantially central position of the insulating coating in a top view was selected as a measurement location, and the film thickness at the measurement location was measured. FIG. 18 shows the measurement results of these film thicknesses. “Before treatment” indicates the thickness of the coating film before treatment, and “after treatment” indicates the thickness of the insulating film. From the measurement results of FIG. 18, even when the plasma treatment and the heat treatment are performed in the plasma treatment apparatus 10A, as in the case where the plasma treatment apparatus 10 performs the plasma treatment and the heat treatment unit U2 performs the heat treatment, the film thickness It was confirmed that it was thin.

(Results of refractive index measurement)
The refractive index of each insulating coating of Examples 9 to 12 was measured. As the refractive index, the refractive index for light with a wavelength of 633 nm was measured. For each of Examples 9 to 12, the refractive index of the coating film before the treatment was also measured. The refractive index was measured by a spectroscopic ellipsometry method using a film measuring device (type Aleris8350; manufactured by KLA Tencor). Further, a substantially central position of the insulating coating in a top view was selected as a measurement location, and the refractive index at the measurement location was measured. Utilizing the tendency that the refractive index increases as the density of the insulating coating increases, the density of the insulating coating is evaluated using the refractive index as an index.

FIG. 19 shows the measurement results of the refractive index of each insulating coating of Examples 9 to 12. From the measurement result of FIG. 19, it was confirmed that the refractive index was increased, that is, the density was improved by performing the solvent removal, the plasma treatment, and the heat treatment. Even when the plasma processing apparatus 10A performs the plasma processing and the heat treatment, the density is improved as in the case where the plasma processing apparatus 10 performs the plasma treatment and the heat treatment unit U2 performs the heat treatment. confirmed.

(Measurement result of etching rate)
The etching rate in wet etching was measured for each of the insulating coatings of Examples 11 and 12 and Comparative Example 9. Specifically, when a 0.5 wt% diluted hydrofluoric acid solution (Diluted HydroFluoric acid: DHF) is used as the etching solution, the amount (thickness) etched per minute is the edging rate [nm/min]. Evaluated as. Dilute hydrofluoric acid has a function of dissolving a silicon oxide film, and the lower the etching rate is, the more difficult it is for the insulating film to be scraped during wet etching (higher etching resistance).

FIG. 20 shows the etching rate evaluation results for the insulating coatings of Examples 11 and 12 and Comparative Example 9. From the evaluation results of FIG. 20, it was confirmed that the etching rates of the insulating coatings of Examples 11 and 12 which had been subjected to the plasma treatment were lower than those of Comparative Example 9 which was not subjected to the plasma treatment. Further, the etching rate of the insulating coating of Example 11 using the processing gas containing ammonia when generating the plasma gas is further lower than that of Example 12 using the processing gas containing hydrogen and nitrogen. Was confirmed.

[Another example of atmosphere control]
In the above-described embodiment, the atmosphere control of the heat treatment space is performed during the solvent removal in step S02 and the heat treatment in step S04, but the atmosphere control may be performed in the case of performing other processing. For example, the substrate processing system 1 may control the atmosphere of the processing space when applying the polysilazane composition to the wafer W. As an example, the processing module 11 may have a coating unit U101 (coating unit) shown in FIG. 21, instead of the coating unit U1. The coating unit U101 is different from the coating unit U1 in that it further includes a housing 240 and a gas supply unit 250.

The housing 240 houses the wafer W held by the rotation holding unit 20 and the nozzle 34 of the liquid supply unit 30. A transfer port for the wafer W may be provided in the housing 240, and a shutter that can be opened and closed may be provided at the transfer port. The housing 240 forms a coating processing space for performing coating processing.

The gas supply unit 250 is configured to supply gas into the housing 240 (coating processing space). For example, the gas supply unit 250 supplies nitrogen gas into the housing 240. By supplying a gas such as nitrogen gas from the gas supply unit 250, the concentration of oxygen in the housing 240 may be maintained at 150 ppm or less, 100 ppm or less, or 50 ppm or less, for example. May be maintained at.

The gas supply unit 250 includes a gas supply source 253, a valve 252, and a pipe 254. The gas supply source 253 functions as a gas supply source. The valve 252 switches between an open state and a closed state according to an instruction from the control device 100. The gas supply source 253 sends out gas into the housing 240 (coating processing space) via the pipe 254 when the valve 252 is in the open state. As described above, the coating unit U101 forms the coating film AF (coating film before solvent removal) by coating the wafer W with the polysilazane composition in a nitrogen atmosphere.

The coating unit U101 (coating unit U1) may have a gas supply unit that supplies a gas such as nitrogen gas to a space in the liquid supply unit 30 where the polysilazane composition (coating liquid L) is exposed to the outside air. ..

In the process of step S01 of applying the polysilazane composition to the front surface Wa of the wafer W, the control device 100 sets the valve 252 to the open state and applies the nitrogen gas from the gas supply source 253 into the application processing space. The unit U101 may be controlled. The control device 100 rotates the wafer W by the rotation holding unit 20 in the nitrogen atmosphere in which the nitrogen gas is supplied by the gas supply unit 250 into the coating processing space, while the liquid supply unit 30 supplies the polysilazane composition to the wafer W. It may be supplied to the surface Wa.

In the heat treatment unit U2 illustrated in FIG. 4, as in the coating unit U101, the gas supply unit 50 supplies nitrogen gas or the like to the heat treatment space to control the atmosphere. By supplying nitrogen gas or the like into the chamber 40 by the gas supply unit 50, for example, the concentration of oxygen in the chamber 40 may be maintained at 150 ppm or less, may be maintained at 100 ppm or less, and may be 50 ppm. May be maintained below.

Atmosphere control may be performed when the wafer W is transferred, other than the coating process and the heat treatment. The processing module 11 has, for example, a gas supply unit that is formed between the coating unit U101 (coating unit U1) and the thermal processing unit U2 and that supplies a gas such as nitrogen gas to a transfer space for transferring the wafer W. May be. When the wafer W on which the coating film AF of the polysilazane composition is formed is transferred to the heat treatment unit U2 in the processing module 11, the control device 100 causes the transfer space in the processing module 11 to supply nitrogen gas by the gas supply unit. May be.

FIG. 22 shows the analysis results (oxygen component ratio) in the coating film when the atmosphere was controlled under various conditions. The component ratio was analyzed using X-ray photoelectron spectroscopy (XPS: X-ray Photoelectron Spectroscopy). FIG. 22 shows a legend of Conditions 1 to 5 which are various conditions of atmosphere control. “Coat” indicates the atmospheric condition of the processing space in forming the coating film in step S01, and “Transfer” indicates the transfer space of the transfer space when the wafer W is transferred to the heat treatment unit U2 after forming the coating film in step S01. Atmosphere conditions are shown, and "Bake" shows the atmosphere conditions of the processing space in the solvent removal in step S02. "N2" indicates that the treatment was performed under a nitrogen atmosphere, and "Air" indicates that the treatment was performed under an air atmosphere.

In FIG. 22, the composition ratio of oxygen at the sputtering time of 2 minutes is shown in the coating film after the coating of the coating liquid L, the removal of the solvent, the plasma treatment, and the heat treatment of steps S01 to S04. There is. The processing is performed under the same conditions except for the atmosphere control. Comparing the results of Conditions 1 to 4 with the results of Condition 5, by performing the treatment under a nitrogen atmosphere in at least one of the application of the coating liquid L in step S01 and the removal of the solvent in step S02, the oxygen content can be increased. It can be seen that is decreasing. Comparing the results of Conditions 1 to 3 with the results of Condition 4, it can be seen that, in the application of the coating liquid L in step S01, the oxygen content is further reduced by performing the treatment in a nitrogen atmosphere. Comparing the results of

Conditions

1 and 2 with the results of Condition 3, in addition to the application of the coating liquid L in step S01, the removal of the solvent in step S02 is performed under a nitrogen atmosphere, whereby the oxygen content is increased. It can be seen that is further reduced. Comparing the results of Condition 1 with the results of Condition 2, it can be seen that the oxygen content is further reduced by setting the transfer space to be a nitrogen atmosphere.

In the substrate processing method executed in the substrate processing system 1 including the plasma processing apparatus 10A illustrated above, applying the polysilazane composition to the wafer W means applying the polysilazane composition to the wafer W in a nitrogen atmosphere. Contains. In this case, the reaction between the polysilazane compound and oxygen is suppressed during the formation of the coating film of the polysilazane composition, and the increase of the oxygen content in the coating film can be suppressed.

Next, an embodiment in which the coating unit U101 and the plasma processing apparatus 10A are used will be described with reference to FIG.

(Example 13)
An insulating coating film according to Example 13 was formed in the same manner as the insulating coating film according to Example 11 except that the coating liquid L was applied in step S01 under a nitrogen atmosphere.

(Measurement result of etching rate)
The etching rate in wet etching was measured for each of the insulating coatings of Examples 11 and 13. Specifically, when a 0.25 wt% dilute hydrofluoric acid solution (Diluted HydroFluoric acid: DHF) is used as the etching solution, the amount (thickness) etched per minute is the edging rate [nm/min]. Evaluated as.

FIG. 23 shows the etching rate evaluation results for the insulating coatings of Examples 11 and 13. From the evaluation results of FIG. 20, the etching rate of the insulating coating of Example 13 in which the coating liquid L was applied in a nitrogen atmosphere was lower than that in Example 11 in which the coating liquid L was applied in the air atmosphere. Was confirmed.

[Other]
The timing of forming the silicon nitride film from the coating film of the polysilazane composition is not limited to before the formation of the resist film. The substrate processing system 1 may form a silicon nitride film from a coating film of the polysilazane composition after the photosensitive film is exposed and developed by the coating/developing device 2. For example, the substrate processing system 1 may form a silicon nitride film from the coating film of the polysilazane composition on the surface Wa of the wafer W that has been subjected to the plasma etching process after forming the resist pattern. The silicon nitride film may be formed from the coating film of the polysilazane composition on the wafer W at any position.

An insulating coating may be formed on the front surface Wa of the wafer W by performing the processing of steps S01 to S04 on the wafer W having a concavo-convex pattern (for example, a resist pattern) formed on the front surface Wa. It is considered that when the film is formed by applying the coating liquid, the filling into the recess is performed without problems (without generating voids), as compared with the case where the film is formed by CVD. Since the above-described substrate processing method can achieve the same quality as that of the silicon nitride film formed by CVD, the substrate processing method is applied to the wafer W having the unevenness on the surface Wa from the viewpoint of embedding the film in the recess. It is even more useful to do so.

The insulating coating formed from the coating film of the polysilazane composition may be used for any purpose. For example, the insulating coating may be formed as a hard mask (sacrificial film) when etching is performed, or the insulating coating may be formed as a permanent film remaining in a semiconductor product formed from the wafer W.

The heating time in the heat treatment of step S04 affects the film stress (stress) that the coating film receives. The magnitude of the film stress changes according to the heating time in the heat treatment of step S04. On the other hand, from the evaluation results of Examples 1 to 8 shown in FIGS. 12, 14, and 15, there is no significant change in the quality (refractive index and etching rate) of the coating film depending on the heating time. Therefore, it is possible to adjust the film stress applied to the coating film by adjusting the heating time in the heat treatment of step S04.

The heating temperature (for example, the temperature of the heating plate or the temperature of the heating nitrogen gas) in the heat treatment of step S04 also affects the film stress (stress) that the coating film receives. The magnitude of the film stress changes according to the heating temperature in the heat treatment of step S04. On the other hand, even if the heating temperature is changed, the quality of the coating film (etching rate and refractive index) does not change significantly. Therefore, the film stress applied to the coating film can be adjusted by adjusting the heating temperature in the heat treatment of step S04.

The heating for removing the solvent in step S02 and the heat treatment in step S04 may be performed by different heat treatment units. The solvent removal in step S02 may be performed by a method other than heating. For example, the substrate processing system 1 may remove the solvent from the coating film AF by placing the wafer W on which the coating film AF is formed in a decompression device having a processing space in which the pressure is reduced.

The substrate to be processed is not limited to a semiconductor wafer, and may be, for example, a glass substrate, a mask substrate, an FPD (Flat Panel Display), or the like.

[Example]
Example 1. A substrate processing method according to one aspect of the present disclosure is to apply a polysilazane composition to a substrate to form a coating film, remove a solvent in the coating film, and remove the solvent from the coating film. , Performing plasma treatment with plasma of an inert gas and heat treating the coating film subjected to the plasma treatment. In this substrate processing method, the coating film from which the solvent has been removed is subjected to plasma treatment using plasma of an inert gas, whereby the refractive index of the insulating coating obtained is increased and the etching resistance is improved. That is, it is possible to improve the quality of the silicon nitride film formed from the coating film containing the polysilazane compound.

Example 2. In the substrate processing method of Example 1, removing the solvent in the coating film may include heating the coating film. For example, a unit for heating for removing a solvent and a unit for performing heat treatment after plasma treatment can be shared, and an apparatus (system) for performing substrate treatment can be simplified.

Example 3. In the substrate processing method of Example 2, heating the coating film may include heating the coating film under a nitrogen atmosphere. In this case, it is possible to prevent the surface of the coating film from reacting with oxygen during heating for removing the solvent, and to suppress the formation of an oxide film on the surface of the coating film.

Example 4. In the substrate processing method of any of Examples 1 to 3, the inert gas may contain nitrogen. In this case, it is possible to achieve both securing the film thickness of the insulating coating and increasing the refractive index.

Example 5. In the substrate processing method of Example 4, the processing gas for generating plasma may contain hydrogen. In this case, since the plasma of the inert gas is promoted by hydrogen, the plasma treatment can be performed more efficiently.

Example 6. In the substrate processing methods of Examples 1 to 5, applying the polysilazane composition to the substrate may include applying the polysilazane composition to the substrate under a nitrogen atmosphere. In this case, the reaction between the polysilazane compound and oxygen is suppressed during the formation of the coating film of the polysilazane composition, and the increase of the oxygen content in the coating film can be suppressed.

Example 7. In the substrate processing methods of Examples 1 to 6, the heat treatment of the coating film may include heating the coating film during a period that overlaps with at least a part of the execution period of the plasma treatment on the coating film. In this case, the plasma treatment and the heat treatment are at least partially overlapped in the execution period, so that the throughput can be improved.

Example 8. In a substrate processing method according to another aspect of the present disclosure, a film containing a polysilazane compound formed by applying a polysilazane composition to a substrate is subjected to plasma processing using plasma of an inert gas. In this case, similarly to the above, it is possible to improve the quality of the silicon nitride film formed from the coating film containing the polysilazane compound.

Example 9. A substrate processing system according to another aspect of the present disclosure is a coating unit that coats a substrate with a polysilazane composition to form a coating film, a solvent removal unit that removes a solvent in the coating film, and a coating solution from which the solvent has been removed. A plasma processing unit that performs plasma processing on the film with an inert gas plasma and a heat treatment unit that heat-treats the plasma-treated coating film are provided. With this configuration, similarly to the above, it becomes possible to improve the quality of the silicon nitride film formed from the coating film containing the polysilazane compound.

Example 10. In the substrate processing system of Example 9, the solvent removal unit may remove the solvent in the coating film by heating the coating film. For example, it is possible to share the unit that constitutes the solvent removal unit and the heat treatment unit, and it is possible to simplify the substrate processing system.

Example 11. In the substrate processing system of Example 10, the solvent removal unit may remove the solvent in the coating film by heating the coating film in a nitrogen atmosphere. In this case, it is possible to prevent the surface of the coating film from reacting with oxygen during heating for removing the solvent, and to suppress the formation of an oxide film on the surface of the coating film.

Example 12. In the substrate processing system of any of Examples 9-11, the inert gas may include nitrogen. In this case, it is possible to achieve both securing the film thickness of the insulating coating and increasing the refractive index.

Example 13. In the substrate processing system of Example 12, the processing gas for generating the plasma may include hydrogen. In this case, since the plasma of the inert gas is promoted by hydrogen, the plasma treatment can be performed more efficiently.

Example 14. In the substrate processing system of any of Examples 9 to 13, the coating section may form a coating film by coating the substrate with the polysilazane composition under a nitrogen atmosphere. In this case, the reaction between the polysilazane compound and oxygen is suppressed during the formation of the coating film of the polysilazane composition, and the increase of the oxygen content in the coating film can be suppressed.

Example 15. In the substrate processing system of any one of Examples 9 to 14, the heat treatment section may heat the coating film during a period that overlaps at least a part of the execution period of the plasma treatment by the plasma treatment section. In this case, the plasma treatment and the heat treatment are at least partially overlapped in the execution period, so that the throughput can be improved.

The above embodiment includes the following configurations.

(Appendix 1)
Applying a polysilazane composition to a substrate to form a coating film;
Removing the solvent in the coating film,
Subjecting the coating film from which the solvent has been removed to plasma treatment with plasma of an inert gas;
A substrate processing method including.
(Appendix 2)
A coating section for coating the substrate with the polysilazane composition to form a coating film;
A solvent removal unit for removing the solvent in the coating film,
A plasma processing unit that performs plasma processing using plasma of an inert gas on the coating film from which the solvent has been removed,
A substrate processing system comprising:

1... Substrate processing system, 2... Coating/developing apparatus, 10, 10A... Plasma processing apparatus, U1, U101... Coating unit, U2... Heat treatment unit, W... Wafer.

Claims

Applying a polysilazane composition to a substrate to form a coating film;
Removing the solvent in the coating film,
Subjecting the coating film from which the solvent has been removed to plasma treatment with plasma of an inert gas;
Heat-treating the coating film subjected to the plasma treatment,
A substrate processing method including.
The substrate processing method according to claim 1, wherein removing the solvent in the coating film includes heating the coating film.
The substrate processing method according to claim 2, wherein heating the coating film includes heating the coating film under a nitrogen atmosphere.
The substrate processing method according to claim 1, wherein the inert gas contains nitrogen.
The substrate processing method according to claim 4, wherein the processing gas for generating the plasma contains hydrogen.
The substrate processing method according to any one of claims 1 to 5, wherein applying the polysilazane composition to the substrate includes applying the polysilazane composition to the substrate under a nitrogen atmosphere.
7. The heat treatment of the coating film includes heating the coating film in a period overlapping with at least a part of an execution period of the plasma treatment of the coating film. The substrate processing method described.
A substrate treatment method in which a film containing a polysilazane compound formed by applying a polysilazane composition to the substrate is subjected to plasma treatment by plasma of an inert gas.
A coating section for coating the substrate with the polysilazane composition to form a coating film;
A solvent removal unit for removing the solvent in the coating film,
The coating film from which the solvent has been removed, a plasma processing unit that performs plasma processing using plasma of an inert gas,
A heat treatment unit for heat treating the coating film subjected to the plasma treatment;
A substrate processing system comprising:
The substrate processing system according to claim 9, wherein the solvent removal unit removes the solvent in the coating film by heating the coating film.
The substrate processing system according to claim 10, wherein the solvent removal unit removes the solvent in the coating film by heating the coating film in a nitrogen atmosphere.
The substrate processing system according to any one of claims 9 to 11, wherein the inert gas contains nitrogen.
The substrate processing system according to claim 12, wherein the processing gas for generating the plasma contains hydrogen.
The substrate processing system according to any one of claims 9 to 13, wherein the coating unit forms the coating film by coating the substrate with the polysilazane composition under a nitrogen atmosphere.
The substrate processing system according to any one of claims 9 to 14, wherein the heat treatment unit heats the coating film in a period that overlaps at least a part of an execution period of the plasma treatment by the plasma treatment unit.