TWI881020B - Coating film forming device and coating film forming method - Google Patents

Abstract

The subject of the present invention is to improve the embedding property of a coating film when the coating film is formed in a manner of embedding a concave pattern formed on a substrate. The solution is a coating film forming device that supplies a coating liquid to a substrate to form a coating film, wherein the device comprises: a loading portion that carries the aforementioned substrate having a concave pattern formed on the surface; a first gas supply portion that supplies a first gas having a kinematic viscosity higher than that of air to the surface of the substrate loaded on the aforementioned loading portion; a modified liquid supply portion that supplies the modified liquid to the surface of the aforementioned substrate in order to replace the first gas in the aforementioned concave portion with a modified liquid that improves the wettability of the aforementioned coating liquid on the surface of the aforementioned substrate; and a coating liquid supply portion that supplies the aforementioned coating liquid to the substrate to which the aforementioned modified liquid is supplied in order to form the aforementioned coating film that fills the aforementioned concave portion and covers the surface of the aforementioned substrate.

Description

Coating film forming device and coating film forming method

The present invention relates to the technical field of supplying a coating liquid to a substrate to form a coating film.

In the manufacturing process of semiconductor devices, a process of coating a semiconductor wafer (hereinafter referred to as a "wafer") with a coating liquid to form a coating film is performed. As the coating film, a photoresist film for forming a photoresist pattern is known, for example, as described in Patent Document 1. The photoresist film is formed by, for example, rotating a wafer held by a rotating chuck while ejecting a photoresist liquid from a nozzle toward the center of the wafer so that the photoresist liquid is coated on the entire surface of the wafer.

Patent document 1 describes a coating device for coating a substrate with a coating liquid, and a gas nozzle device is provided for supplying a laminar flow forming gas having a kinematic viscosity coefficient (kinematic viscosity) greater than that of the atmosphere gas to the surface of the wafer. Then, a downflow of the atmosphere gas is formed on the surface of the wafer, and the atmosphere gas flowing on the surface of the wafer atmosphere gas is mixed with the laminar flow forming gas. In this way, the kinematic viscosity of the atmosphere on the surface of the wafer is increased, and the area of the wafer surface where the laminar flow is formed is expanded. After the surface of the wafer is coated with the coating liquid, a laminar flow is formed in this way, and the device is constructed in a manner to suppress the formation of uneven coating (windmill marks) by the coating film formed due to the drying of the coating liquid. [Prior technical document] [Patent document]

[Patent Document 1] Japanese Patent Application Publication No. 2007-189185

[The problem that the invention wants to solve]

The present invention provides a technique for improving the embedding property of a coating film when the coating film is formed in a manner of embedding a concave pattern formed in a substrate. [Means for solving the problem]

The coating film forming device of the present invention supplies a coating liquid to a substrate to form a coating film, wherein the device comprises: a loading portion for loading the substrate having a concave pattern formed on the surface; a first gas supply portion for supplying a first gas having a kinematic viscosity higher than that of air to the surface of the substrate loaded on the loading portion; a modified liquid supply portion for supplying the modified liquid to the surface of the substrate in order to replace the first gas in the concave portion with a modified liquid for improving the wettability of the coating liquid on the surface of the substrate; and a coating liquid supply portion for supplying the coating liquid to the substrate to which the modified liquid is supplied in order to form the coating film filled in the concave portion and covering the surface of the substrate. [Effect of the invention]

According to the present invention, it is possible to provide a technique for improving the embedding property of a coating film when the coating film is formed so as to embed a concave pattern formed in a substrate.

[First implementation form]

A photoresist film forming apparatus for forming a photoresist film on a substrate, i.e., a wafer W, is described with respect to the coating film forming method of the first embodiment. As shown in FIG. 1 and FIG. 2 , the photoresist film forming apparatus 1 has a placing portion, i.e., a rotating suction cup 31, which sucks the central portion of the back side of the wafer W and horizontally places the wafer W. The rotating suction cup 31 is connected to a rotating mechanism, i.e., a driving portion 33, through a shaft portion 32, and can freely rotate around a vertical axis and freely rise and fall while holding the wafer W through the driving portion 33.

Symbol 34 in FIG. 1 is a cup portion with an opening on the upper side, which is provided on the outer side of the periphery of the wafer W held by the aforementioned rotating suction cup 31 in a manner of surrounding the wafer W. On the bottom side of the cup portion 34, a liquid receiving portion 35 in the shape of a recess is provided on the lower side of the periphery of the wafer W so as to cover the entire periphery. The liquid receiving portion 35 is divided into an outer area and an inner area, and a drain port 36 is provided at the bottom of the outer area. Furthermore, an exhaust port 37 is provided at the bottom of the aforementioned inner area, and one end of an exhaust pipe 39 is connected to the exhaust port 37. The other end of the exhaust pipe 39 is connected to an exhaust means such as an exhaust flow path of a factory through a valve V1. Furthermore, a filter unit 80 for supplying air downward to form a downflow is provided above the cup portion 34. Therefore, the surrounding of the cup portion 34 is an atmospheric atmosphere.

The photoresist film forming apparatus 1 is provided with a photoresist nozzle 4 for supplying a photoresist liquid having a viscosity of 50 cP or more, for example, 100 cP, to the wafer W. In addition, the photoresist film forming apparatus 1 is provided with a diluent nozzle 5 of a modifying liquid supply unit for supplying a modifying liquid, i.e., a diluent, for improving the wettability of a coating liquid such as the photoresist liquid on the surface of the wafer W. Furthermore, the photoresist film forming apparatus 1 is provided with a first gas supply unit, i.e., a He gas nozzle 6, for supplying a first gas, i.e., a helium (He) gas, to the wafer W, and a second gas supply unit, i.e., an Ar gas nozzle 7, for supplying a second gas, i.e., an argon (Ar) gas, to the wafer W.

One end of a photoresist supply tube 41 is connected to the photoresist nozzle 4. The other end of the photoresist supply tube 41 is connected to a photoresist supply source 43 storing photoresist liquid via a valve V2 and a flow control unit 42. One end of a diluent supply tube 51 is connected to the diluent nozzle 5. The other end of the diluent supply tube 51 is connected to a diluent supply source 53 storing diluent via a valve V3 and a flow control unit 52. One end of a He gas supply tube 61 is connected to the He gas nozzle 6. The other end of the He gas supply tube 61 is connected to a He gas supply source 63 storing He gas via a valve V4 and a flow control unit 62. One end of an Ar gas supply pipe 71 is connected to the Ar gas nozzle 7. The other end of the Ar gas supply pipe 71 is connected to an Ar gas supply source 73 storing Ar gas via a valve V5 and a flow control unit 72.

As shown in FIG. 2 , the photoresist nozzle 4 and the diluent nozzle 5 are supported by the front ends of the arms 44 and 54, respectively. The base ends of the arms 44 and 54 are connected to movable bodies 45 and 55, respectively, which are configured to be freely movable along the guide rail 8, so that the photoresist nozzle 4 and the diluent nozzle 5 can be freely moved between the upper position of the center of the wafer W and the standby position (not shown) outside the cup 34.

In addition, the He gas nozzle 6 and the Ar gas nozzle 7 are also similarly supported by the front ends of the arms 64 and 74, respectively. The base ends of the arms 64 and 74 are connected to the movable bodies 65 and 75, respectively, so that they can be freely raised and lowered. Then, the movable bodies 65 and 75 are configured to move along the guide rail 81, and can move freely between the upper position of the center of the wafer W and the standby position (not shown) outside the cup 34. The arm 64, the movable body 65, and the guide rail 81 are equivalent to the first gas supply portion moving mechanism that moves the first gas supply position on the surface of the substrate relative to the surface of the substrate. The first gas supply unit moving mechanism and the driving unit 33 of the rotary chuck 31 are equivalent to a relative moving mechanism for moving the first gas supply position on the surface of the substrate relative to the surface of the substrate. Furthermore, the photoresist film forming apparatus 1 of the first embodiment has two He gas nozzles 6 and Ar gas nozzles 7 of the same structure, but one of the two is omitted in FIGS. 1 and 2.

The photoresist film forming apparatus 1 is provided with a control unit 9 such as a computer. The control unit 9 has a program storage unit, in which a program including commands for implementing the transfer of the wafer W between the external transport mechanism and the rotary chuck 31, the rotation of the rotary chuck 31, and the supply sequence of He gas, Ar gas, photoresist liquid, and diluent is stored. The program is stored in a storage medium such as an optical disk, a hard disk, an MO (magnetic optical disk), and a memory card, and installed in the control unit 9.

FIG3 is a longitudinal sectional side view showing an example of the surface of a wafer W processed by a coating film forming device, i.e., a photoresist film forming device 1. In addition, a pattern (recess pattern) formed by recesses 100 is formed on the surface of the wafer W. The recess pattern includes, for example, a plurality of parallel grooves. The wafer W is used, for example, in a manufacturing process of a device having a 3D NAND structure, and the aspect ratio of the recess 100 is relatively large. If the height and width of the recess 100 are set to L1 and L2, respectively, the aspect ratio (L1/L2) is, for example, greater than 20.

In the photoresist film forming device 1, a so-called pre-wetting is performed in which the surface of the wafer W is moistened with a diluent to improve the wettability of the surface of the wafer W with the photoresist liquid. Pre-wetting is performed by rotary coating in which the liquid supplied to the center of the wafer W is diffused to the peripheral portion by the rotation of the wafer W. After the pre-wetting with the diluent, the photoresist liquid is applied by rotary coating. By performing the pre-wetting, the photoresist liquid is spread on the surface of the wafer W without stagnation and quickly by rotary coating. When the pre-wetting is not performed, since the spreadability of the photoresist liquid during rotary coating is low, the photoresist liquid is drawn into the air on the surface of the wafer W, and there is a risk that the photoresist film may contain bubbles. That is, by pre-wetting, the mixing of bubbles into the photoresist film can be suppressed.

In the photoresist film forming apparatus 1, the above-mentioned pre-wetting is performed after He gas is supplied to the wafer W. It is assumed that the pre-wetting is performed without supplying the He gas to the wafer W. Regarding the recess 100 of the wafer W, for example, there is a state in which the aspect ratio becomes larger as described above. The inside of the recess 100 is filled with air that forms the atmosphere of the photoresist film forming apparatus 1. If pre-wetting is performed in this state, the diluent enters the recess 100, pushes out the air in the recess 100, and flows toward the periphery of the wafer W. However, due to the shape of the recess 100 as described above, the airflow of the pushed-out air is turbulent. As a result, the diluent is retained in the concave portion 100 while being entrained with air, and there is a risk that air bubbles will remain in the pre-wetted concave portion 100. If the photoresist is applied in this state, the air bubbles will also remain in the photoresist film.

Therefore, as described above, in the photoresist film forming device 1, He gas is supplied to the wafer W, and the air in the recess 100 is replaced with He gas having a higher kinematic viscosity than the air. If the kinematic viscosity is high, the Reynolds number Re=vL/ν, which is an indicator of the flow of the fluid, will become smaller (relative average velocity v of the fluid, distance L of the fluid flow, kinematic viscosity ν). In addition, kinematic viscosity ν=μ/ρ (viscosity coefficient μ, density ρ), and a high kinematic viscosity tends to have a relatively small density. Therefore, with respect to the He gas with a high kinematic viscosity, when it is pushed from the recess 100 by the diluent and flows on the surface of the wafer W, the flow disturbance can be suppressed due to the low Re, and it is easy to move on the surface of the wafer W due to its low density. That is, it is possible to prevent the air bubbles from being drawn into the diluent and remaining in the recess 100 as bubbles.

Furthermore, in the photoresist film forming device 1, Ar gas is supplied after the supply of He gas and before pre-wetting. The kinematic viscosity of the Ar gas is lower than that of the He gas, so after being supplied to the surface of the wafer W, it is difficult for the Ar gas to flow on the surface of the wafer W compared to the He gas. That is, since the Ar gas is easily retained on the surface of the wafer, it forms a layer in a manner of sealing the recess 100. That is, it plays the role of a cover that suppresses the release of He gas from the recess 100. Furthermore, the kinematic viscosity of the Ar gas is lower than that of the air. Therefore, as described above, air is supplied to the cup portion 34 by the FFU80, but it is suppressed from being affected by the flow of the air and removed from the surface of the wafer W. Therefore, it is more ideal when used as the aforementioned cover. Furthermore, high and low kinematic viscosity refer to the high and low kinematic viscosity when the wafer W is processed under the same temperature environment.

Furthermore, for easier understanding, the description is made by using the photoresist film forming apparatus 1 to process a wafer W having a relatively large aspect ratio of the recess 100. However, in the process of the photoresist film forming apparatus 1, it is also possible to more reliably prevent the residual bubbles from being formed on a wafer W having a small aspect ratio. That is, the process can be performed regardless of the shape of the recess pattern of the wafer W.

The following describes the processes performed by the photoresist film forming apparatus 1 in order. While the cup 34 is being exhausted at a relatively small first exhaust volume, the wafer W is placed on the rotary suction cup 31 by a transport mechanism (not shown) and the center of the back side is sucked. Next, two He gas nozzles 6 are moved from the outside of the cup 34 and are located above the center and the periphery of the wafer W, respectively. Furthermore, two Ar gas nozzles 7 are also moved from the outside of the cup 34 and are located near the He gas nozzle 6.

In addition to the movement of each gas nozzle, the wafer W is rotated at a predetermined rotation speed to blend with the temperature of the surrounding atmosphere and to even out the temperature of each part of the surface. Then, as shown in FIG4 , the wafer W is rotated at a relatively low first rotation speed, such as 0 rpm to 100 rpm, more specifically, 10 rpm, and He gas 101 is ejected from each He gas nozzle 6 toward the center and periphery of the wafer W. The He gas 101 is supplied to the entire surface of the wafer W by diffusion toward the periphery of the wafer W due to centrifugal force and by changes in the supply position due to the rotation of the wafer W. Then, as shown in FIG5 , the air in the recess 100 of the wafer W is replaced by the He gas 101, and the recess 100 is filled with the He gas 101.

For example, if two He gas nozzles 6 are simultaneously supplied with 5 to 100 L of He gas for 5 seconds, the supply of He gas is stopped, and the He gas nozzles 6 are respectively withdrawn from the center and the periphery of the wafer W. While the He gas nozzles 6 are moving, the Ar gas nozzles 7 are located at the center and the periphery of the wafer W, as shown in FIG. 6 , and Ar gas 102 is supplied to the center and the periphery of the wafer W, and the rotation speed of the wafer W is increased to a second relatively high rotation speed, for example, 100 rpm to 300 rpm, more specifically, 200 rpm. The Ar gas 102 is supplied to the entire surface of the wafer W by diffusion toward the periphery of the wafer W due to centrifugal force and the change of the supply position due to the rotation of the wafer W, and is retained on the surface of the wafer W in a manner of blocking the recess 100 as shown in FIG. 7 . For example, if two Ar gas nozzles 7 simultaneously supply 0.5 to 2 L of Ar gas within 1 second, the supply of the Ar gas 102 is stopped, and the Ar gas nozzles 7 are withdrawn to the outside of the cup portion 34.

Next, as shown in FIG8 , the diluent nozzle 5 is positioned at the center of the wafer W, and the diluent 103 is ejected onto the center of the wafer W, and the rotation number of the wafer W is set to a third rotation number that is lower than the second rotation number and higher than the first rotation number, for example, 30 rpm. Furthermore, by changing the rotation number in this way, the opening of the valve V1 is increased, and the exhaust volume in the cup portion 34 is increased, and exhaust is performed at the second exhaust volume. The diluent 103 is diffused from the center of the wafer W toward the periphery by centrifugal force. When diffusing in this way, the He gas 101 in the recess 100 is pushed out of the recess 100 and pushed toward the periphery of the wafer W. As for the Ar gas 102, it is also pushed toward the periphery of the wafer W together with the He gas 101. As for the He gas 101, the flow is not turbulent and it is quickly pushed out from the recess 100. As shown in FIG9 , the He gas 101 in the recess 100 is replaced by the diluent 103. Furthermore, the fact that the He gas 101 does not have such flow turbulence means that the flow of the diluent 103 in contact with the He gas 101 is not turbulent. Then, the diluent 103 reaches the periphery of the wafer W, covers the entire surface of the wafer W, and fills each recess 100 in a manner that does not leave any bubbles.

Next, the supply of the diluent 103 from the diluent nozzle 5 is stopped, and the photoresist nozzle 4 is moved to the center of the wafer W. Then, as shown in FIG. 10 , the photoresist liquid 104 is ejected to the center of the wafer W, and the number of rotations of the wafer W is increased. By rotating the coating, the photoresist liquid 104 is spread toward the periphery on the surface of the wafer W modified by the diluent 103, and is coated on the entire surface of the wafer W. The coated photoresist liquid 104 is mixed with the diluent 103 in the recess 100 and enters the recess 100. As described above, the diluent 103 is filled in the concave portion 100 in advance in a manner without forming any gaps. Therefore, as shown in FIG. 11 , the photoresist liquid 104 is filled in the concave portion 100 in a manner without forming any gaps.

After that, after the supply of the photoresist liquid 104 is stopped, in order to make the thickness of the photoresist liquid 104 film on the surface of the wafer W uniform, the wafer W is rotated at a relatively low rotation number, for example, 100 rpm. Then, as shown in FIG. 12 , the rotation number of the wafer W is increased, for example, to 1500 rpm, to allow the photoresist liquid 104 to dry. As the rotation number increases, the opening of the valve V1 becomes smaller, and the exhaust volume in the cup portion 34 becomes the first relatively low exhaust volume again. As described above, the photoresist liquid 104 is filled in the recess 100 in a manner that does not contain bubbles. Therefore, by utilizing the drying of the photoresist liquid 104 and embedding it in the recess 100 without gaps, a photoresist film covering the entire surface of the wafer W is formed. Thereafter, the rotation of the wafer W is stopped, and the wafer W is handed over to a transport mechanism (not shown) and taken out of the photoresist film forming apparatus 1 .

According to the photoresist film forming apparatus 1 of the first embodiment, after the concave portion 100 on the surface of the wafer W is filled with the He gas 101 having a higher kinematic viscosity than the air, the diluent 103 supplied to the center of the wafer W is spread over the surface of the wafer W, and the He gas 101 in the concave portion 100 is replaced by the diluent 103. Thereafter, the photoresist liquid 104 is applied. Therefore, the flow of the gas discharged from the concave portion 100 and the flow of the diluent 103 contacting the gas are respectively stabilized. As a result, the gas is less likely to be swept into the diluent 103 flowing into the concave portion 100, and the concave portion 100 is filled with the diluent 103 without a gap. Therefore, when the photoresist liquid 104 is applied next, the photoresist liquid 104 can be filled into the recess 100 without any gaps, which can improve the embedding property (filling property) of the photoresist film in the recess 100. In addition, according to the photoresist film forming apparatus 1, the supply of Ar gas 102 can suppress the escape of the aforementioned He gas 101 from the recess 100, which is more ideal. Furthermore, after the supply of He gas, the diluent is quickly pre-wetted, and the processing can be performed without supplying the Ar gas.

In addition, a plurality of He gas nozzles 6 and Ar gas nozzles 7 are provided to discharge He gas 101 and Ar gas 102 to a plurality of locations of the wafer W. Therefore, since the gases can be quickly supplied to the entire surface of the wafer W, the He gas can be more reliably retained in the recess 100 during pre-wetting. That is, the filling property of the photoresist film in the recess 100 can be more reliably improved, which is more ideal.

Furthermore, as described above, the supply amount of He gas to the wafer W is greater than the supply amount of Ar gas to the wafer W. By setting the supply amount in this way, the He gas 101 is more reliably supplied to the recess 100, and the He gas 101 can be prevented from being removed due to being pushed out of the recess 100 by the Ar gas 102, which is more ideal. Furthermore, after the He gas 101 is supplied, the He gas 101 may gradually escape from the recess 100 as time passes. Therefore, it is better to quickly supply the Ar gas 102, and as described above, the supply time of the Ar gas 102 is preferably set shorter than the supply time of the He gas 101.

Furthermore, the first rotation number when He gas 101 is supplied to wafer W is lower than the second rotation number when Ar gas 102 is supplied to wafer W. Therefore, He gas 101 is suppressed from being removed from wafer W due to the centrifugal force of the rotation of wafer W, and Ar gas 102 is rapidly diffused on the surface of wafer W by centrifugal force to cover the surface, thereby suppressing the release of He gas 101 from the recess 100, which is more ideal.

Furthermore, when supplying He gas 101 and Ar gas 102, the He gas 101 filling the concave portion 100 and the Ar gas 102 stagnating at the upper portion of the concave portion 100 are avoided, so it is more ideal to exhaust with a first exhaust volume that is lower than the second exhaust volume when supplying the diluent 103 and the photoresist liquid 104. As the first exhaust volume, the exhaust volume can be set to 0, that is, the exhaust can be stopped. Furthermore, for forming a relatively thick photoresist film, it is necessary to increase the viscosity of the photoresist liquid. Generally speaking, the higher the viscosity of the photoresist liquid, the more difficult it is to fill the concave portion, but in the photoresist film forming device 1, as described above, the diluent is filled in the concave portion 100 with high certainty, which can improve the filling property of the photoresist film into the concave portion 100. That is, it also has the advantage of being able to form a thicker photoresist film by using the relatively high viscosity photoresist liquid as mentioned above.

Regarding the He gas nozzle 6 and the Ar gas nozzle 7, they are separated from each other in the examples shown in Figures 1 and 2, but this is not limited to this structural example. As shown in Figures 13 and 14, a gas supply unit 70 that is an integrated He gas nozzle 6 and Ar gas nozzle 7 may also be used. Specifically, the gas supply unit 70 is composed of one He gas nozzle 6 and one Ar gas nozzle 7 connected in the horizontal direction along the radial direction of the wafer W. Then, two gas supply units 70 are provided for gas supply to the peripheral portion of the wafer W and for gas supply to the central portion of the wafer W, and are respectively connected to the arm portion 64 shown in Figure 2. With the structure in which the nozzles are connected in this way, after the gas is discharged from the He gas nozzle 6, the Ar gas nozzle 7 can quickly move to the position where the He gas nozzle 6 discharges the He gas, and discharge the Ar gas.

Furthermore, as a gas supply section for supplying He gas and Ar gas, a gas supply section 60 that supplies in a spraying manner may be used. That is, the gas supply section is not limited to a nozzle, and may be a gas head. As shown in FIGS. 15 and 16 , for example, a plurality of first gas supply ports 66 and second gas supply ports 76 are arranged side by side below the gas supply section 60. In FIG. 16 , the first gas supply port 66 and the second gas supply port 76 are distinguished by being painted white and black. Furthermore, in FIGS. 17 to 19 below, the first gas supply port 66 and the second gas supply port 76 are distinguished by being painted white and black.

Then, a He gas flow path 67 and an Ar gas flow path 77 are formed to be separated from each other inside the gas supply part 60, and the downstream ends of the He gas flow path 67 and the Ar gas flow path 77 are connected to the aforementioned first gas supply port 66 and the second gas supply port 76, respectively. In addition, the He gas supply pipe 61 and the Ar gas supply pipe 71 described in the first embodiment are connected to the upstream ends of the He gas flow path 67 and the Ar gas flow path 77. Furthermore, the gas supply part 60 is connected to the front end of the arm part 64 described above, and the gas supply part 60 is configured to be freely raised and lowered and freely moved. The gas supply part 60 is equivalent to a lifting body. The operation of the device when the gas supply part 60 is set will be described later.

Furthermore, the gas supply unit 60 for supplying He gas and Ar gas in a spraying manner may be configured to discharge gas toward a region that radially crosses the wafer W, as shown in FIG17 . Alternatively, the gas supply unit 60 may be configured to supply gas toward the entire surface of the wafer W, as shown in FIG18 .

Furthermore, as shown in FIG. 19 , for example, a structure may be a combination of a He gas nozzle 6 and an Ar gas nozzle 7 for supplying gas toward the center of the wafer W, and a gas supply unit 60 for supplying gas in a spray-like manner to the area near the periphery of the wafer W. However, when the gas supply unit is configured to supply He gas and Ar gas to the entire surface of the wafer W as shown in FIG. 18 , the wafer W may not be rotated when the Ar gas and He gas are supplied to the wafer W. Furthermore, the gas supply unit 60 may not be moved in the gas supply shown in the second embodiment. That is, when each gas is supplied to the wafer W, it is not limited to a structure in which the gas supply unit 60 is moved with respect to the wafer W. Then, as in the case of a structure that can supply gas to the entire surface of the wafer W without rotating the wafer W, such as the gas supply unit 60 of FIG. 18 , it is more ideal because the He gas and the Ar gas can be prevented from diffusing from the surface of the wafer W to the outside by the centrifugal force. Furthermore, in the structure of FIG. 19 , each gas can be supplied to the center of the wafer W by utilizing the diffusion of each gas ejected from the He gas nozzle 6 and the Ar gas nozzle 7 without rotating the wafer W. However, for each gas supply unit, the flow path of the He gas and the flow path of the Ar gas are formed separately, but they can also be configured as a common flow path.

[Second embodiment] Next, the photoresist film forming apparatus 10 of the second embodiment will be described with a focus on the differences in structure from the photoresist film forming apparatus 1. The photoresist film forming apparatus 10 is different from the photoresist film forming apparatus 1 in that it has a light irradiation unit, i.e., an LED (light emitting diode) light source group 91, as a heating mechanism for heating the wafer W, as shown in FIG. 20. In addition, the photoresist film forming apparatus of the second embodiment is provided with a gas supply unit 60 instead of the He gas nozzle 6 and the Ar gas nozzle 7.

The LED light source group 91 is composed of, for example, an upper LED light source group 91A and a lower LED light source group 91B respectively arranged on the upper and lower sides of the wafer W placed on the rotating suction cup 31. For example, the light source groups 91A and 91B are respectively composed of a plurality of LED light sources 90. The upper LED light source group 91A is composed of a plurality of LED light sources 90 arranged in a row along the radial direction of the wafer W and spaced apart in the circumferential direction of the wafer W. The lower LED light source group 91B is the same as the upper LED light source group 91A, and is composed of a plurality of LED light sources 90 arranged in a row along the radial direction of the wafer W and spaced apart in the circumferential direction of the wafer W, and the row is arranged in a manner to surround the rotating suction cup 31. As the wafer W rotates, the upper LED light source group 91A and the lower LED light source group 91B irradiate the surface and back of the wafer W respectively, heating the entire surface of the wafer W.

The LED light source group 91 heats the wafer W in such a way that the temperature of the atmosphere in the cup portion 21 becomes, for example, a temperature slightly higher than 23°C, for example, a temperature below 30°C. In this way, the He gas supplied to the wafer W as described above is heated by heating the wafer W. Generally speaking, the viscosity coefficient μ of a gas increases as the temperature rises. The kinematic viscosity ν is expressed as ν=μ/ρ, and since the viscosity coefficient μ increases as the temperature rises, the kinematic viscosity ν also increases. That is, heating the He gas can increase the kinematic viscosity. Thereby, the flow of the He gas filling the recess 100 is made more stable, and the embedding property of the diluent 103 flowing into the recess 100 is further improved. Furthermore, if the temperature of the wafer W becomes too high, the amount of vaporization of the diluent and photoresist liquid will increase when the diluent and photoresist liquid are supplied, so the amount of the liquid required for processing the wafer W will increase. Therefore, it is better to heat the wafer W in a way that the temperature becomes slightly higher than the surrounding atmosphere mentioned above.

The following is an explanation of the processing by the photoresist film forming device 10, focusing on the differences from the processing by the photoresist film forming device 1. After the wafer W is handed over to the rotating chuck 31, it is rotated at a predetermined number of rotations in the same manner as the photoresist film forming device 1 to make the temperature of each part of the surface of the wafer W uniform. Afterwards, as shown in FIG. 21, light is irradiated from the LED light source group 91, and the wafer W is rotated at a predetermined number of rotations, such as 1000 rpm, to heat the wafer W.

In addition to heating the wafer W, the gas supply unit 60 moves from the outside of the cup 34 to the center of the wafer W, and is located at a height with a relatively narrow interval from the surface of the wafer W. Then, the light irradiation from the LED light source group 91 is stopped, and as shown in FIG. 22 , the wafer W is rotated at a rotation speed of, for example, 10 rpm, and the gas supply unit 60 supplies He gas from the first gas supply port 66 while moving horizontally toward the periphery of the wafer W. If the distance between the first supply port 66 of the gas supply unit 60 and the surface of the wafer W during the He gas supply is set to the first distance, the interval between the gas supply unit 60 and the wafer W is relatively narrow as described above, so the first distance is relatively small. Therefore, the supplied He gas can be prevented from being released to the outside of the wafer W, and can more surely enter the recess 100.

When the gas supply part 60 moves to the periphery of the wafer W and supplies He gas to the entire surface of the wafer W, the supply of He gas is stopped and the gas supply part 60 moves to the upper center of the wafer W. Then, the gas supply part 60 rises and the distance between the surface of the wafer W and the gas supply part 60 increases. Then, as shown in FIG. 23 , the wafer W is rotated at a rotation speed of, for example, 200 rpm, while Ar gas is supplied from the second gas supply port 76 and the gas supply part 60 is moved horizontally toward the periphery of the wafer W. When the distance between the second supply port 76 of the gas supply part 60 and the surface of the wafer W during the Ar gas supply is set to a second distance, the second distance is greater than the aforementioned first distance. Since the second distance is relatively large, the collision force between the Ar gas and the wafer W is small, and the pressure of the He gas from the recess 100 caused by the Ar gas can be suppressed. Therefore, after the supply of the Ar gas, the recess 100 is more reliably filled with the He gas.

The gas supply unit 60 for supplying Ar gas moves to the periphery of the wafer W. When the Ar gas is supplied to the entire surface of the wafer W, the supply of Ar gas is stopped and the gas supply unit 60 is withdrawn to the outside of the cup portion 34. Afterwards, the diluent is supplied to the wafer W for pre-wetting as in the first embodiment (FIG. 24). At this time, as described above, the kinematic viscosity ν of the He gas supplied to the wafer W is increased. Therefore, the flow of the He gas is more stable, and the diluent 103 is more reliably filled in the recess 100. Afterwards, similar to the first embodiment, the photoresist liquid is applied to the entire surface of the wafer W. After the supply of the photoresist liquid to the wafer W is stopped, the rotation number of the wafer W becomes a relatively low rotation number for uniformizing the thickness of the photoresist liquid film in the surface of the wafer W. Afterwards, the rotation number of the wafer W increases in a manner to become a relatively high rotation number, for example, 1500 rpm. At the same time as the increase in the rotation number, the light irradiation from the LED light source group 91 to the wafer W begins, and the wafer W is heated again. By heating the wafer W, the photoresist liquid is heated, and its fluidity becomes higher. The photoresist liquid moves in the recess 100 and from the outside of the recess 100 to the inside of the recess 100, and is filled in the recess 100 more reliably without gaps. Then, by heating and rotating the wafer W, the photoresist liquid is gradually dried to form a photoresist film.

Thus, according to the second embodiment, by adjusting the temperature of the wafer W, the photoresist film can be more reliably embedded in the recess 100. Furthermore, according to the second embodiment, by rotating the wafer W and moving the gas supply unit 60 to move the position of supplying He gas and Ar gas within the surface of the wafer W, the He gas can be more reliably and quickly filled into the recess 100 and the surface of the wafer W can be covered with Ar gas. Furthermore, by supplying gas from the He gas supply port 66 and the Ar gas supply port 76 at each height, the He gas can be more reliably filled into the recess 100. The other gas supply parts shown in FIG. 14 to FIG. 19 and the nozzles described in the first embodiment other than the gas supply part 60 used in the second embodiment can also be used by adjusting the height in the same manner as in the second embodiment. Furthermore, when adjusting the distance between the wafer W and the He gas supply port 66 and the Ar gas supply port 76, the height of the gas supply part 60 relative to the wafer W is adjusted, but the height of the wafer W relative to the gas supply part 60 may also be adjusted. That is, the rotary suction plate 31 and the drive part 33 may be connected to the lifting mechanism, and the height of the wafer W relative to the gas supply part 60 may also be changed.

However, in the aforementioned processing example, the light irradiation by the LED light source group 91 is stopped before the supply of He gas to the wafer W. However, light irradiation may also be performed during the supply of the He gas, and the wafer W may be heated. The period before the supply of He gas or during the supply of He gas is set as the first period. In addition, the period from the start of the supply of the diluent to the wafer W to the end of the supply of the photoresist liquid to the wafer W is set as the second period. The period after the discharge of the photoresist liquid is completed is set as the third period. In order to prevent the vaporization of the diluent and the photoresist, as in the aforementioned processing example, the light irradiation from the LED group 91 in the second period is stopped, or set to a low light intensity. Therefore, it is better to set the light intensity of the second period to be relatively small compared to the light intensities of the first period and the third period.

Furthermore, the heating mechanism is not limited to the LED light source group 91, and for example, a heater that heats by electric heating wires may also be used. However, by utilizing the heating caused by light irradiation, the temperature of the wafer W can be rapidly increased, so from the perspective of increasing the processing capacity of the device, it is better to perform the heating caused by light irradiation. Furthermore, the LED light source group 91 also has the effect of turning on and off the LED light source group 91, and the installation of the equipment for adjusting the light intensity does not require a large area, which can suppress the enlargement of the device. Furthermore, the wafer W can be heated in a heating device outside the photoresist film forming device 10, and the heated wafer W can be transported to the photoresist film forming device 10 and supplied with He gas. However, the structure of the photoresist film forming device 10 that is configured to perform LED heating in a device for supplying He gas can prevent the enlargement of the equipment required for processing.

Furthermore, the first gas may be a gas having a kinematic viscosity ν higher than that of air, for example, hydrogen gas. Furthermore, the second gas may be a gas having a kinematic viscosity ν lower than that of air, for example, krypton (Kr) gas. Furthermore, the present invention is not limited to a structure in which the first gas is supplied from a gas supply portion toward a substrate. For example, in the photoresist coating device 1 described above, instead of providing the first gas nozzle 6, the photoresist coating device 1 may be provided in a closed processing chamber. Then, the first gas is configured to be supplied to the processing chamber, and the first gas is filled in the concave pattern 100 by replacing the atmosphere in the processing chamber with the first gas. The configuration may be such that the modifying liquid and the coating liquid are applied to the wafer W afterwards.

Furthermore, the coating film forming device of the present invention is not limited to a device for forming a photoresist film, and can be used as a device for forming an interlayer insulating film, for example. That is, as a coating liquid, a chemical solution for forming an interlayer insulating film can also be used. In addition, a chemical solution for forming an anti-reflection film can also be used. Furthermore, after the supply of He gas, when applying the diluent, as described above, it is not limited to diffusing from the center of the wafer W to the periphery. For example, the diluent can be ejected from a nozzle having a long strip-shaped ejection port along the radius of the wafer W, and the wafer W can be rotated to supply the diluent to the entire surface of the wafer W. In addition, the diluent may be supplied to the entire surface of the wafer W by discharging the diluent from a nozzle having a discharge port longer than the diameter of the wafer W and moving the nozzle from one end to the other end of the wafer W. For example, the photoresist liquid may be supplied in the same manner as the diluent, and the supply of the photoresist liquid to the wafer W is not limited to the first and second embodiments.

Furthermore, the embodiments disclosed this time are all illustrative and not restrictive. The aforementioned embodiments may be omitted, replaced, altered, or combined in various forms without departing from the scope of the patent application and its subject matter of the appendix. [Embodiment]

In order to verify the effect of the present invention, the photoresist film forming device shown in Figures 1 and 2 is used to form a wafer W with a recess 100 shown in Figure 3, and the coating film forming method of the photoresist liquid shown in the embodiment is performed, and the cross-section of the surface portion of the wafer W using an electron microscope is used as an embodiment. In addition, an example in which the coating film forming process is performed on the wafer W in the same manner as the embodiment except that the process of supplying the first gas and the process of supplying the second gas are not included is used as a comparative example. Figures 26 and 27 respectively reveal the cross-section of the surface portion of the wafer W of the embodiment and the comparative example. As shown in Figure 26, in the embodiment, the photoresist film 104 can be filled in the recess pattern 100 without gaps. On the other hand, as shown in FIG. 27 , in the comparative example, the photoresist film 104 inside the concave pattern 100 cannot be fully filled, and a gap 105 is formed.

According to the results, it can be seen that the embedding property of the coating film in the concave portion 100 can be improved by supplying the first gas to the wafer W before applying the modifying liquid and the coating liquid to the wafer W and then supplying the second gas to the wafer W. Therefore, according to the present invention, when the coating liquid is applied to the substrate forming the concave portion 100, the embedding property of the coating liquid in the concave portion 100 can be improved.

1: Photoresist film forming device 4: Photoresist nozzle 5: Diluent nozzle 6: He gas nozzle 7: Ar gas nozzle 8: Guide rail 9: Control unit 10: Photoresist film forming device 31: Rotating suction cup 32: Shaft 33: Driving unit 34: Cup 35: Liquid receiving unit 36: Liquid discharge port 37: Air discharge port 39 : Exhaust pipe 41: Photoresist supply pipe 42: Flow control unit 43: Photoresist supply source 44: Arm 45: Moving body 51: Diluent supply pipe 52: Flow control unit 53: Diluent supply source 54: Arm 55: Moving body 60: Gas supply unit 61: He gas supply pipe 62: Flow control unit 63 :He gas supply source 64: Arm 65: Moving body 66: First gas supply port 67: He gas flow path 71: Ar gas supply pipe 72: Flow control unit 73: Ar gas supply source 74: Arm 75: Moving body 76: Second gas supply port 77: Ar gas flow path 80: Filter unit 81: Guide rail 90: LED light source 91A: Upper LED light source group 91B: Lower LED light source group 100: Concave pattern (concave) 101: He gas 102: Ar gas 103: Diluent 104: Photoresist liquid W: Wafer V1: Valve V2: Valve V3: Valve V4: Valve V5: Valve

[FIG. 1] A longitudinal sectional side view of a photoresist film forming apparatus according to the first embodiment. [FIG. 2] A top view of a photoresist film forming apparatus according to the first embodiment. [FIG. 3] A longitudinal sectional side view of a surface structure of a substrate used in the first embodiment. [FIG. 4] An explanatory diagram of a coating film forming method according to the first embodiment. [FIG. 5] An explanatory diagram of a coating film forming method according to the first embodiment. [FIG. 6] An explanatory diagram of a coating film forming method according to the first embodiment. [FIG. 7] An explanatory diagram of a coating film forming method according to the first embodiment. [FIG. 8] An explanatory diagram of a coating film forming method according to the first embodiment. [FIG. 9] An explanatory diagram of a coating film forming method according to the first embodiment. [FIG. 10] An explanatory diagram of the coating film forming method of the first embodiment. [FIG. 11] An explanatory diagram of the coating film forming method of the first embodiment. [FIG. 12] An explanatory diagram of the coating film forming method of the first embodiment. [FIG. 13] A side view of another example of the photoresist film forming device. [FIG. 14] A top view of another example of the photoresist film forming device. [FIG. 15] A side view of another example of the photoresist film forming device. [FIG. 16] A top view of another example of the photoresist film forming device. [FIG. 17] A top view of another example of the photoresist film forming device. [FIG. 18] A top view of another example of the photoresist film forming device. [FIG. 19] A top view of another example of the photoresist film forming device. [FIG. 20] A longitudinal cross-sectional view of a photoresist film forming apparatus according to the second embodiment. [FIG. 21] A diagram illustrating a coating film forming method according to the second embodiment. [FIG. 22] A diagram illustrating a coating film forming method according to the second embodiment. [FIG. 23] A diagram illustrating a coating film forming method according to the second embodiment. [FIG. 24] A diagram illustrating a coating film forming method according to the second embodiment. [FIG. 25] A diagram illustrating a coating film forming method according to the second embodiment. [FIG. 26] A cross-sectional view showing a surface of a substrate according to an embodiment. [FIG. 27] A cross-sectional view showing a surface of a substrate according to a comparative example.

100: Concave pattern

101: He gas

102: Ar gas

W: Wafer

Claims (13)

A coating film forming device is a coating film forming device that supplies a coating liquid to a substrate to form a coating film, and is characterized by comprising: a loading portion for loading the substrate having a concave pattern formed on the surface; a first gas supply portion for supplying a first gas having a kinematic viscosity higher than that of air to the surface of the substrate loaded on the loading portion; and a modified liquid supply portion for replacing the first gas in the concave portion with the modified liquid in the concave portion to lift the coating film on the surface of the substrate. A liquid-wetting reforming liquid is supplied to the surface of the substrate; a coating liquid supplying part supplies the coating liquid to the substrate supplied with the reforming liquid in order to form the coating film that fills the concave part and covers the surface of the substrate; and a second gas supplying part supplies a second gas having a lower kinematic viscosity than the first gas to the substrate supplied with the first gas before being supplied with the reforming liquid. The coating film forming device as described in claim 1, wherein the second gas is a gas having a higher kinematic viscosity than air. The coating film forming device as described in claim 1, wherein the first gas supply unit and the second gas supply unit supply the first gas and the second gas, respectively, in such a manner that the supply amount of the first gas supplied to the substrate is greater than the supply amount of the second gas supplied to the substrate. The coating film forming device as described in claim 1, wherein the first gas supply unit has a first supply port for supplying the first gas at a position at a first distance from the surface of the substrate; and the second gas supply unit has a second supply port for supplying the second gas at a position at a second distance greater than the first distance from the surface of the substrate. The coating film forming device as described in claim 4, wherein the first supply port and the second supply port are opened to a lifting body which is commonly provided at the first supply port and the second supply port and is lifted relative to the substrate. A coating film forming device is a coating film forming device that supplies a coating liquid to a substrate to form a coating film, and is characterized by comprising: a loading portion for loading the substrate having a concave pattern formed on the surface; a first gas supply portion for supplying a first gas having a kinematic viscosity higher than that of air to the surface of the substrate loaded on the loading portion; a modified liquid supply portion for supplying the modified liquid to the surface of the substrate in order to replace the first gas in the concave portion with a modified liquid that improves the wettability of the coating liquid on the surface of the substrate; and a coating liquid supply portion for supplying the coating liquid to the substrate to which the modified liquid is supplied in order to form the coating film that fills the concave portion and covers the surface of the substrate, wherein the first gas The gas supply unit is provided with a relative movement mechanism for moving the supply position of the first gas on the surface of the substrate relative to the surface of the substrate. The coating film forming device is further provided with a rotation mechanism for rotating the mounting unit to rotate the substrate and forming the relative movement mechanism. A second gas supply unit is provided for supplying a second gas having a higher kinematic viscosity than the first gas to the substrate supplied with the first gas and before the modified liquid is supplied. The substrate is rotated at a first rotation number during the supply of the first gas by the rotation mechanism, and is rotated at a second rotation number higher than the first rotation number during the supply of the second gas by the rotation mechanism. The coating film forming device as described in claim 6, wherein the relative moving mechanism is provided, and the relative moving mechanism includes a first gas supply unit moving mechanism for moving the first gas supply unit relative to the substrate. A coating film forming device is a coating film forming device that supplies a coating liquid to a substrate to form a coating film, and is characterized by comprising: a loading portion for loading the substrate having a concave pattern formed on the surface; a first gas supply portion for supplying a first gas having a kinematic viscosity higher than that of air to the surface of the substrate loaded on the loading portion; and a modified liquid supply portion for replacing the first gas in the concave portion with the aforementioned coating liquid to wet the surface of the aforementioned substrate. a modified liquid of a property, supplying the modified liquid to the surface of the substrate; a coating liquid supplying section, supplying the coating liquid to the substrate supplied with the modified liquid in order to form the coating film filled in the concave portion and covering the surface of the substrate; and a heating mechanism, heating the substrate placed on the placing section before or during the first period of the first gas supply in order to increase the kinematic viscosity of the first gas. The coating film forming device as described in claim 8, wherein the heating mechanism is a light irradiation unit that irradiates light to heat the substrate. The coating film forming device as described in claim 9, wherein the light irradiation unit irradiates light in a manner such that the light intensity in the second period from the start of supply of the modifying liquid to the substrate to the end of supply of the coating liquid to the substrate is smaller than the light intensity in the first period and the third period after the supply of the coating liquid to the substrate is stopped. A coating film forming device as described in any one of claims 1 to 10, wherein the first gas is helium. A coating film forming device is a coating film forming device that supplies a coating liquid to a substrate to form a coating film, and is characterized by comprising: a loading portion for loading the substrate having a concave pattern formed on the surface; a first gas supply portion for supplying a first gas having a kinematic viscosity higher than that of air to the surface of the substrate loaded on the loading portion; and a reforming liquid supply portion for replacing the first gas in the concave portion with the coating liquid to improve the moisture content of the surface of the substrate. The modified liquid is supplied to the surface of the substrate; the coating liquid supply part supplies the coating liquid to the substrate supplied with the modified liquid in order to form the coating film filled in the concave part and covering the surface of the substrate; and the second gas supply part supplies the second gas having a higher kinematic viscosity than the first gas to the substrate supplied with the first gas and before being supplied with the modified liquid, wherein the second gas is argon. A coating film forming method is a coating film forming method for supplying a coating liquid to a substrate to form a coating film, and is characterized by comprising: a process of placing the substrate having a concave pattern formed on the surface on a mounting portion; a process of supplying a first gas having a higher kinematic viscosity than air to the surface of the substrate placed on the mounting portion; a process of supplying a modifying liquid for improving the wettability of the coating liquid on the surface of the substrate to the surface of the substrate to replace the first gas in the concave portion with the modified liquid; a process of supplying the coating liquid to the substrate supplied with the modified liquid to form the coating film that fills the concave portion and covers the surface of the substrate; and a process of supplying a second gas having a lower kinematic viscosity than the first gas to the substrate supplied with the first gas and before the supply of the modified liquid.

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