JP2024103435A - SUBSTRATE PROCESSING METHOD AND SUBSTRATE PROCESSING APPARATUS - Google Patents

Abstract

To obtain a good pattern of inorganic resist.SOLUTION: A substrate processing method comprises: a process for developing a substrate on which an inorganic resist film is formed on a base film and exposed, using a developing solution to form a pattern of the inorganic resist; a process for supplying embedding solution to the developed substrate and filling the space between adjacent convexities in the pattern; a process for drying the filled embedding solution to form an embedding film on the substrate; a process for reducing the thickness of the embedded film by UV light.SELECTED DRAWING: Figure 7

Description

This disclosure relates to a substrate processing method and a substrate processing apparatus.

The semiconductor manufacturing method disclosed in Patent Document 1 includes, in a step of developing a photosensitive film formed on a semiconductor substrate or a step of cleaning the semiconductor substrate after the development of the photosensitive film, at least one of a step of developing the photosensitive film using a developing solution having a surface tension lower than that of pure water, and a step of cleaning the semiconductor substrate using a cleaning solution having a surface tension lower than that of pure water.

Japanese Patent Application Publication No. 5-326392

The technology disclosed herein produces good patterns of inorganic resist.

One aspect of the present disclosure is a substrate processing method including the steps of: developing a substrate on which an inorganic resist film has been formed and which has been subjected to an exposure process, with a developer, to form a pattern of the inorganic resist; supplying a filling liquid to the developed substrate to fill spaces between adjacent convex portions in the pattern; drying the filling liquid to form a filling film on the substrate; and reducing the thickness of the filling film with ultraviolet light.

This disclosure makes it possible to obtain good patterns of inorganic resist.

1 is an explanatory diagram showing an outline of an internal configuration of a wafer processing apparatus as a substrate processing apparatus according to a first embodiment; 2 is a diagram showing an outline of the internal configuration of the front side of the wafer processing apparatus of FIG. 1. 2 is a diagram showing an outline of the internal configuration of the rear side of the wafer processing apparatus of FIG. 1 . FIG. 2 is a vertical cross-sectional view showing the outline of the configuration of a developing module. FIG. 2 is a cross-sectional view showing the outline of the configuration of a development module. 2 is a flowchart showing main steps of an example of processing by the wafer processing apparatus of FIG. 1 . 2A to 2C are partially enlarged cross-sectional views each showing a state of a wafer W in each process of processing by the wafer processing apparatus of FIG. 1; 13 is a diagram showing an outline of an internal configuration on the rear side of a wafer processing apparatus as a substrate processing apparatus according to a second embodiment. FIG. 9 is a flowchart showing main steps of an example of processing by the wafer processing apparatus of FIG. 8 . FIG. 13 is a diagram showing an outline of an internal configuration on the front side of a wafer processing apparatus as a substrate processing apparatus according to a third embodiment. 2 is a flowchart showing main steps of an example of processing by the wafer processing apparatus of FIG. 1 . FIG. 13 is an explanatory diagram showing an outline of an internal configuration of a wafer processing apparatus as a substrate processing apparatus according to a fourth embodiment. 13 is a diagram showing an outline of the internal configuration of the front side of the wafer processing apparatus of FIG. 12. 13 is a flowchart showing an example of a determination sequence related to pattern collapse by the wafer processing apparatus of FIG. 12 . FIG. 13 is an explanatory diagram showing an outline of an internal configuration of a wafer processing apparatus as a substrate processing apparatus according to a fourth embodiment.

In photolithography, a manufacturing process for semiconductor devices, etc., a series of processes are performed to form a desired resist pattern on a substrate such as a semiconductor wafer (hereinafter referred to as "wafer"). The series of processes includes, for example, a resist coating process in which a resist liquid is supplied onto the substrate to form a resist coating (hereinafter referred to as "resist film"), an exposure process in which the resist film is exposed to light in a predetermined pattern, a PEB (Post Exposure Bake) process in which the substrate is heated after exposure in order to promote chemical reactions within the exposed resist film, and a development process in which the exposed resist film is developed to form a resist pattern.

Traditionally, chemically amplified resists have been widely used as resists, but in recent years, non-chemically amplified inorganic resists (e.g., metal-containing resists) are sometimes used. These inorganic resists are expected to be more suitable for forming fine patterns. However, even when inorganic resists are used, the pattern may collapse, which is a type of defect.

Therefore, the technology disclosed herein suppresses the occurrence of defects such as pattern collapse and produces a good inorganic resist pattern.

The substrate processing method and substrate processing apparatus according to this embodiment will be described below with reference to the drawings. Note that in this specification and the drawings, elements having substantially the same functional configurations are given the same reference numerals to avoid redundant description.

First Embodiment
Fig. 1 is an explanatory diagram showing an outline of the internal configuration of a wafer processing apparatus as a substrate processing apparatus according to a first embodiment. Figs. 2 and 3 are diagrams showing an outline of the internal configuration of the front side and rear side of the wafer processing apparatus shown in Fig. 1, respectively.

The wafer processing apparatus 1 in FIG. 1 forms an inorganic resist pattern on a wafer W as a substrate. The inorganic resist used by the wafer processing apparatus 1 is, for example, a metal-containing resist or a silicon (Si)-containing resist. The metal-containing resist contains, for example, tin oxide as an inorganic component, and the Si-containing resist contains silicon as an inorganic component.

As shown in Figures 1 to 3, the wafer processing apparatus 1 includes a cassette station 10, a processing station 11, and an interface station 12, and is connected to an exposure apparatus E. The exposure apparatus E performs exposure processing on the wafer W, specifically, exposure processing using, for example, EUV (Extreme Ultra-Violet) light. The cassette station 10, the processing station 11, and the interface station 12 are aligned horizontally in this order and connected together. The exposure apparatus E is connected to the interface station 12 on the opposite side to the processing station 11.

In the following, the direction in which the interface station 12 and the exposure device E are connected is referred to as the width direction, and the direction perpendicular to the connection direction, i.e., the width direction, when viewed from above is referred to as the depth direction.

The cassette station 10 carries in and out a cassette C, which is a container capable of housing a plurality of wafers W therein.
The cassette station 10 has a cassette mounting table 20 provided at, for example, one end in the width direction (the negative side in the Y direction in the figure). A plurality of mounting plates 21, for example four mounting plates 21, are provided on the cassette mounting table 20. The mounting plates 21 are arranged in a row in the depth direction (the X direction in the figure). The mounting plates 21 can be used to mount the cassettes C when they are carried in and out of the wafer processing apparatus 1.

The cassette station 10 is also provided with a transfer module 23 for transferring the wafer W, for example, on the other side in the width direction (the positive side in the Y direction in the figure). The transfer module 23 has a transfer arm 23a configured to be movable in the depth direction (the X direction in FIG. 1). The transfer arm 23a of the transfer module 23 is also configured to be movable in the vertical direction and around the vertical axis. This transfer module 23 can transfer the wafer W between the cassette C on each mounting plate 21 and the transfer module 51 of the transfer tower 50 described below.

In addition, the cassette station 10 may be provided with a storage section (not shown) in which the cassette C is placed and stored, above the cassette placement table 20 or in a portion farther from the exposure device E than the cassette placement table 20 (the negative side portion in the Y direction in the figure).

The processing station 11 is equipped with multiple processing modules that perform specific processes such as development.

The processing station 11 is divided into multiple blocks (two in the illustrated example) each equipped with various modules. It has a processing block BL1 on the interface station 12 side, and a transfer block BL2 on the cassette station 10 side.

The processing block BL1 has, for example, a first block G1 on the front side (negative side in the X direction in FIG. 1) and a second block G2 on the back side (positive side in the X direction in FIG. 1).

For example, in the first block G1, as shown in FIG. 2, multiple liquid processing modules, such as a development module 30 as a development section and a filling section, a base film forming module 31, and a resist coating module 32 are arranged in this order from the bottom.

The developing module 30 develops the wafer W with a developer, that is, wet development. As the developer, for example, a mixture of propylene glycol monomethyl ether acetate (PGMEA) and acetic acid, 2-heptanone, or the like is used.
By development in the developing module 30, an inorganic resist pattern having a large number of convex portions of a predetermined shape is formed on the wafer W. When the inorganic resist is a negative metal-containing resist, for example, in the metal-containing resist film after the exposure process and the PEB process, an area where a condensation reaction has progressed becomes insoluble in the developing fluid such as the developer, and remains as the above pattern.

The developing module 30 also performs a filling process on the wafer W. The filling process involves supplying a filling liquid to the wafer W to fill the spaces between adjacent convex portions in adjacent inorganic resist patterns. When the filled filling liquid is dried, a filling film is formed on the wafer W.

The undercoat film forming module 31 supplies the undercoat film material, which is a processing liquid, to the wafer W to form an undercoat film of inorganic resist (hereinafter, inorganic resist film). The undercoat film is specifically an organic film, more specifically a spin-on carbon (SOC) film having a carbon content of 80% or more and 90% or less. If a fluorine-based gas is required to etch the undercoat film using the inorganic resist pattern as a mask, the chamber of the etching device may be contaminated. In this regard, if the undercoat film is an organic film, the undercoat film can be etched with an oxygen-based gas, so that contamination of the chamber can be suppressed. In addition, by forming such an SOC film having a carbon content of 80% or more and 90% or less as the undercoat film, the adhesion with the inorganic resist film formed thereon is improved, and it is considered that it is easier to form a fine pattern of inorganic resist without collapsing it.

The resist coating module 32 is a resist coating section that applies inorganic resist to the wafer W to form an inorganic resist film.

For example, four developing modules 30, four base film forming modules 31, and four resist coating modules 32 are arranged in the width direction (Y direction in the figure). The number and arrangement of these developing modules 30, four base film forming modules 31, and four resist coating modules 32 can be selected arbitrarily.

In the developing module 30, the base film forming module 31, and the resist coating module 32, a predetermined processing liquid is applied onto the wafer W, for example, by a spin coating method. In the spin coating method, for example, the processing liquid is discharged onto the wafer W from a discharge nozzle, and the wafer W is rotated to diffuse the processing liquid onto the surface of the wafer W. The configuration of the developing module 30 will be described later.

For example, in the second block G2, a plurality of heat treatment modules 40 are arranged vertically and widthwise (Y direction in the figure) as shown in Fig. 3. The number and arrangement of the heat treatment modules 40 can also be selected arbitrarily.
The thermal treatment module 40 performs thermal treatment such as heating and cooling on the wafer W.

As shown in FIG. 1, the processing block BL1 is provided with a transport path R1 extending in the width direction between the first block G1 and the second block G2. In the processing block BL1, a plurality of developing modules 30, base film forming modules 31, and resist coating modules 32 are arranged along the transport path R1 extending in the width direction. A transport module R2 that transports the wafer W is arranged on the transport path R1.

The transfer module R2 has a transfer arm R2a that can move, for example, in the width direction (Y direction in the figure), the vertical direction, and the direction around the vertical axis. The transfer module R2 moves the transfer arm R2a holding the wafer W within the transfer path R1, and can transfer the wafer W to a predetermined module within the surrounding first block G1, second block G2, transfer tower 50 described below, and transfer tower 60. For example, multiple transfer modules R2 are arranged vertically as shown in FIG. 3, and can transfer the wafer W to a predetermined module of approximately the same height in each of the first block G1, second block G2, transfer towers 50, 60.

In addition, a shuttle transfer module R3 is provided on the transfer path R1 to transfer the wafer W linearly between the transfer tower 50 and the transfer tower 60.

The shuttle transport module R3 can move the supported wafer W linearly in the Y direction and transport the wafer W between modules of the transfer tower 50 and the transfer tower 60, which are at approximately the same height.

As shown in FIG. 1, the transfer block BL2 has a transfer tower 50 at the center in the depth direction (X direction in the figure). Specifically, the transfer tower 50 is provided at a position in the transfer block BL2 adjacent to the transport path R1 of the processing block BL1 in the width direction (Y direction in the figure). As shown in FIG. 3, the transfer tower 50 has multiple transfer modules 51 arranged vertically stacked.

As shown in FIG. 1, a UV irradiation module 52 is provided as an ultraviolet ray irradiation section at the front end of the transfer block BL2. As shown in FIG. 2, the UV irradiation modules 52 may also be provided so as to overlap in the vertical direction.

The UV irradiation module 52 irradiates the wafer W with ultraviolet light, specifically, irradiates the entire upper surface of the wafer W, i.e., the entire surface, with ultraviolet light in an oxygen-containing atmosphere.

As shown in FIG. 1, the interface station 12 is provided between the processing station 11 and the exposure apparatus E, and serves to transfer the wafer W between them.
A transfer tower 60 is provided at a position adjacent to the transport path R1 of the processing block BL1 in the width direction (Y direction in the figure) in the interface station 12. As shown in FIG. 3, the transfer tower 60 has a plurality of transfer modules 61 arranged vertically stacked on top of each other.

Also, as shown in FIG. 1, the interface station 12 is provided with a transport module R4.

The transfer module R4 is provided at a position adjacent to the transfer tower 60 in the width direction (Y direction in the figure), and has a transfer arm R4a that is movable, for example, in the depth direction (X direction in the figure), the vertical direction, and the direction around the vertical axis. The transfer module R4 holds a wafer W on the transfer arm R4a and can transfer the wafer W between the multiple transfer modules 61 of the transfer tower 60 and the exposure device E.

Furthermore, transfer modules R5 and R6 are provided in transfer block BL2.

The transfer module R5 is provided at the rear side of the transfer tower 50 (the positive side in the X direction in the figure) and has a transfer arm R5a that can move freely, for example, in the vertical direction. The transfer module R5 holds a wafer W on the transfer arm R5a and can transfer the wafer W between multiple transfer modules 51 of the transfer tower 50.

The transfer module R6 is provided between the transfer tower 50 and the UV irradiation module 52, and has a transfer arm R6a that is movable, for example, in the vertical direction and in the direction around the vertical axis. The transfer module R6 holds a wafer W on the transfer arm R6a and can transfer the wafer W between the multiple transfer modules 51 and the UV irradiation module 52 of the transfer tower 50.

Furthermore, the wafer processing apparatus 1 has a control unit 3 that controls the wafer processing apparatus 1, including the control of the transfer module. The control unit 3 is, for example, a computer equipped with a processor such as a CPU and a memory, and has a program storage unit (not shown). The program storage unit stores a program including instructions for controlling the processing by the wafer processing apparatus 1. The above program may be recorded on a computer-readable storage medium H, and may be installed from the storage medium H into the control unit 3. The storage medium H may be temporary or non-temporary.

<Development Module 30>
Next, the configuration of the developing module 30 will be described with reference to Figures 4 and 5. Figures 4 and 5 are a vertical cross-sectional view and a horizontal cross-sectional view, respectively, showing the outline of the configuration of the developing module 30.

As shown in Figures 4 and 5, the developing module 30 has a processing container 100 whose interior can be sealed. A loading/unloading port (not shown) for the wafer W is formed on the side of the processing container 100 facing the transfer module R2, and an opening/closing shutter (not shown) is provided at the loading/unloading port.

A spin chuck 110 is provided in the center of the processing vessel 100 as a substrate holder. The spin chuck 110 holds a wafer W and is configured to be freely rotatable. The spin chuck 110 has a horizontal upper surface, and the upper surface is provided with, for example, a suction port (not shown) for sucking the wafer W. The wafer W can be adsorbed and held on the spin chuck 110 by suction from this suction port.

A chuck driver 111 is provided below the spin chuck 110 as a rotation mechanism. The chuck driver 111 is equipped with, for example, a motor, and can rotate the spin chuck 110 at a desired speed, thereby rotating the wafer W held by the spin chuck 110 at a desired speed. The chuck driver 111 is also provided with a lifting drive source, for example, a cylinder, which allows the spin chuck 110 to be freely raised and lowered.

A cup 112 is provided around the spin chuck 110 to receive and collect liquid that splashes or falls from the wafer W. The bottom surface of the cup 112 is connected to a discharge pipe 113 that discharges the collected liquid, and an exhaust pipe 114 that evacuates the atmosphere inside the cup 112.

As shown in FIG. 5, rails 120, 121 extending along the Y direction (left and right direction in FIG. 5) are formed on the negative X direction side (downward in FIG. 5) of cup 112. Rails 120, 121 are formed, for example, from the outside of cup 112 on the negative Y direction side (left direction in FIG. 5) to the outside of cup 112 on the positive Y direction side (right direction in FIG. 5). A first arm 122 and a second arm 123 are attached to rails 120, 121, respectively.

The first arm 122 supports a developer nozzle 124 that ejects developer and supplies it onto the wafer W, as shown in Figures 4 and 5.

The first arm 122 can be moved freely on the rail 120 by the nozzle drive unit 125 shown in FIG. 5. This allows the developer nozzle 124 to move from a waiting section 126 installed outside the cup 112 on the positive Y-direction side to above the center of the wafer W in the cup 112. The first arm 122 can also be moved up and down by the nozzle drive unit 125, allowing the height of the developer nozzle 124 to be adjusted.

A developer supply source (not shown) is connected to the developer nozzle 124. In addition, a supply pipe (not shown) between the developer nozzle 124 and the developer supply source is provided with a group of supply devices including a valve and a flow rate regulator for controlling the flow of the developer.

As shown in Figures 4 and 5, the second arm 123 supports a filling liquid nozzle 127 that ejects the filling liquid and supplies it onto the wafer W. The filling liquid is, for example, an organic processing liquid that forms an organic film as a filling film, and more specifically, is, for example, an organic polymer solution with an organic polymer as a solute and an organic solvent as a solvent. The filling film formed by the filling liquid and the base film formed by the base film forming module 31 may be the same type of organic film. Here, "the same type" means a type that has the same resistance to etching by ultraviolet irradiation in an oxygen-containing atmosphere.

The second arm 123 can be moved freely on the rail 121 by a nozzle drive unit 128 serving as a moving mechanism shown in FIG. 5. This allows the embedding liquid nozzle 127 to move from a waiting unit 129 installed outside the cup 112 on the negative Y-direction side to above the peripheral region of the wafer W in the cup 112. In addition, the second arm 123 can be moved up and down freely by the nozzle drive unit 128, allowing the height of the embedding liquid nozzle 127 to be adjusted.

A supply source of the embedding liquid (not shown) is connected to the embedding liquid nozzle 127. In addition, a supply pipe (not shown) between the embedding liquid nozzle 127 and the embedding liquid supply source is provided with a group of supply devices including a valve and a flow rate regulator for controlling the flow of the embedding liquid.

The configurations of the base film forming module 31 and the resist coating module 32 are similar to that of the developing module 30. However, the number of ejection nozzles that eject the treatment liquid and the treatment liquid supplied from the ejection nozzles are different between the base film forming module 31, the resist coating module 32, and the developing module 30.

<Example of Processing by Wafer Processing Apparatus 1>
Next, an example of processing by the wafer processing apparatus 1 will be described. Fig. 6 is a flow chart showing main steps of the example of processing by the wafer processing apparatus 1. Fig. 7 is a partially enlarged cross-sectional view showing a schematic state of the wafer W in each step of the above processing. Each of the following steps is executed under the control of the control unit 3 based on a program stored in a program storage unit (not shown).

First, a wafer W is carried into the wafer processing apparatus 1 (step S1).
Specifically, for example, first, the transfer module 23 takes out the wafer W from the cassette C on the cassette mounting table 20 and transfers it to the transfer module 51 of the transfer tower 50 in the transfer block BL2.

Next, a base film formation process is performed on the wafer W, and a base film is formed on the wafer W. Specifically, for example, the wafer W is transported by the transport module R2 to the base film formation module 31 in the processing block BL1, and a base film material is spin-coated on the surface of the wafer W, and a base film such as an SOC film is formed to cover the surface of the wafer W.

Next, a resist coating process is performed on the wafer W, and an inorganic resist film is formed on the wafer W (step S3).
Specifically, for example, the wafer W is transported by the transport module R2 to the resist coating module 32, and a negative metal-containing resist as an inorganic resist is spin-coated onto the surface of the wafer W, and an inorganic resist film such as a coating of a metal-containing resist (hereinafter, a "metal-containing resist film") is formed to cover the surface of the wafer W.

Next, the wafer W is subjected to a pre-applied bake (PAB) process (step S4).
Specifically, the wafer W is transferred to the heat treatment module 40 for PAB treatment, and heat treatment is performed on the wafer W. Thereafter, the wafer W is transferred to the transfer module 61 of the transfer tower 60 in the interface station 12.

Next, the wafer W is subjected to an exposure process (step S5).
Specifically, for example, the wafer W is transferred to the exposure apparatus E by the transfer module R4, and a predetermined pattern formed on a mask is transferred by EUV light onto an inorganic resist film on the wafer W. The predetermined pattern is, for example, a line-and-space pattern with a pitch of 30 nm. Thereafter, the wafer W is transferred to the transfer module 61 of the transfer tower 60 by the transfer module R4.

Next, the wafer W is subjected to a PEB process (post-exposure bake) (step S6).
Specifically, for example, the wafer W is transferred by the transfer module R2 to the heat treatment module 40 for PEB treatment, and the wafer W is subjected to heat treatment.

Next, the wafer W is developed (step S7).
Specifically, for example, the wafer W is transferred to the developing module 30 by the transfer module R2, and the wafer W is subjected to a developing process using a developer, that is, a wet developing process.

More specifically, the wafer W is transferred by the transfer module R2 into the developing module 30 and is attracted and held by the spin chuck 110.
Next, the developer nozzle 124 on the waiting section 126 moves to above the center of the wafer W held by suction on the spin chuck 110. Thereafter, while the wafer W is rotated by the spin chuck 110, the developer nozzle 124 discharges the developer and supplies it onto the surface of the wafer W. The supplied developer is spread over the entire surface of the wafer W by centrifugal force to form a developer puddle covering the entire surface of the wafer W. Next, the discharge of the developer is stopped, and static development is performed in which the wafer W is stationary for a predetermined time. This progresses the development of the resist film on the wafer W, and an inorganic resist pattern RP having a large number of convex portions RP1 of a predetermined shape is formed on the base film U of the wafer W, as shown in FIG. 7A.

After that, a cleaning liquid may be supplied onto the surface of the wafer W from a cleaning liquid nozzle (not shown) to remove the developer.

In one embodiment, the wafer W remains wet until the start of the embedding process in the next step S8. Specifically, the wafer W remains wet means, for example, a state in which the developer D remains on the entire surface of the wafer W as shown in FIG. 7A, and in the case where a cleaning liquid is supplied after the developer is supplied, means a state in which the cleaning liquid remains on the entire surface of the wafer W.

After development, the wafer W is subjected to a filling process (step S8). That is, a filling liquid is supplied to the wafer W to fill the spaces between adjacent protrusions RP1 in the inorganic resist pattern RP, and then the filling liquid is dried to form a filling film F on the wafer W, as shown in FIG. 7(B).

The embedding process is performed by the development module 30 .
Specifically, for example, the embedding liquid nozzle 127 on the waiting section 129 moves to above the center of the wafer W held by suction on the spin chuck 110. Thereafter, while the wet wafer W is rotated by the spin chuck 110 as described above, the embedding liquid is discharged from the embedding liquid nozzle 127 and supplied onto the surface of the wafer W. The supplied embedding liquid is spread over the entire surface of the wafer W by centrifugal force, and the gaps between adjacent protrusions RP1 in the inorganic resist pattern RP are filled over the entire surface of the wafer W. Thereafter, the discharge of the embedding liquid is stopped, and in this state, the wafer W is rotated, the embedding liquid is dried, and an embedding film F is formed on the wafer W as shown in FIG. 7B. The thickness of the formed embedding film F is, for example, 20% to 90% of the height of the protrusions RP1 of the inorganic resist pattern RP.
The filling film F is an organic film. As described above, the filling film F may be the same type of organic film as the base film U. The relationship of the carbon content is preferably inorganic resist film (i.e., inorganic resist pattern RP)<filling film F<base film U.

By forming such a buried film F, it is possible to prevent the inorganic resist pattern RP from collapsing, specifically, it is possible to prevent the protruding portion RP1 of the inorganic resist pattern RP from collapsing. More specifically, it is possible to prevent the protruding portion RP1 of the inorganic resist pattern RP from peeling off from the base film U and collapsing.

Next, the wafer W is subjected to a post-bake process (step S9).
Specifically, for example, the wafer W is transported by the transport module R2 to a heat treatment module 40 for post-baking, and the wafer W is subjected to a heat treatment. This causes the inorganic resist pattern RP to solidify. That is, as shown in FIG. 7C, an inorganic resist pattern Rs having a solidified protrusion Rs1 is formed on the wafer W. The solidification of the inorganic resist pattern RP also improves the adhesion between the inorganic resist pattern Rs and the undercoat film U. Furthermore, the buried film F is further dried by the post-baking.

Next, the thickness of the filling film F is reduced (step S10).
Specifically, for example, the wafer W is transferred by the transfer module R2 to the transfer module 51 of the transfer tower 50 of the transfer block BL2. Next, the wafer W is transferred by the transfer module R6 to the UV irradiation module 52, where the wafer W is subjected to an ultraviolet irradiation process, and the entire buried film F is removed, for example, as shown in FIG. 7D. In the UV irradiation module 52, the entire surface of the wafer W is irradiated with ultraviolet rays in an oxygen-containing atmosphere (specifically, for example, an atmospheric gas atmosphere), and the buried film F on the wafer W is removed by ozone generated by the ultraviolet rays in the surrounding atmosphere. After the ultraviolet irradiation process, the wafer W is transferred to the transfer module 51 of the transfer tower 50.

Then, the wafer W is unloaded from the wafer processing apparatus 1 (step S11).
Specifically, the wafer W is returned to the cassette C in a procedure reverse to that of step S1.

This completes the series of processes performed by wafer processing device 1.

The wafer W is then transferred to, for example, an etching device (not shown) outside the wafer processing apparatus 1. In the external etching device, etching of the base film U is performed using the inorganic resist pattern as a mask.
In addition, when the filling film and the base film are the same type of organic film, the filling film reduction process in step S10 may also involve removing the base film, i.e., etching, using the inorganic resist pattern as a mask, which simplifies the series of processes up to etching the film to be etched below the base film using the inorganic resist pattern as a mask.

<Main Effects of the First Embodiment>
As described above, the wafer processing apparatus 1 executes a process of forming an inorganic resist pattern by forming an inorganic resist film on the undercoat film U, performing an exposure process, and developing the wafer W with a developer. The wafer processing apparatus 1 also executes a process of supplying a filling liquid to the developed wafer to fill spaces between adjacent convex portions in the inorganic resist pattern, and a process of drying the filling liquid to form a filling film on the wafer W. Therefore, according to the wafer processing apparatus 1, at least the bottoms of the convex portions in the inorganic resist pattern formed by development can be supported by the filling film. Therefore, it is possible to suppress the occurrence of collapse of the inorganic resist pattern. Specifically, it is possible to suppress the occurrence of collapse of the inorganic resist pattern until the inorganic resist pattern is solidified and its adhesion to the undercoat film is increased. More specifically, it is possible to suppress the occurrence of collapse of the inorganic resist pattern due to peeling from the undercoat film, at least until the end of the post-bake process.

After drying the embedding liquid to form the embedding film, the wafer processing apparatus 1 further performs a process of reducing the thickness of the embedding film by using ultraviolet light. That is, in the wafer processing apparatus 1, the embedding liquid is dried before being removed. Alternatively, it is possible to remove the embedding liquid in liquid form without drying it. However, with this method, there is a risk that the inorganic resist pattern will collapse due to the surface tension of the embedding liquid, i.e., due to the capillary phenomenon caused by the embedding liquid. In contrast, as described above, the wafer processing apparatus 1 dries the embedding liquid before removing it, so that the surface tension of the embedding liquid can be prevented from acting on the protruding parts of the inorganic resist pattern during removal, and therefore the inorganic resist pattern can be prevented from collapsing due to the above surface tension.

In this manner, according to this embodiment, collapse of the inorganic resist pattern can be suppressed, and therefore a good inorganic resist pattern can be obtained.
The inventors compared the minimum line width at which the pattern does not collapse for an inorganic resist line and space pattern when a buried film is formed as in this embodiment and when it is not formed. When a buried film is not formed, the minimum line width is about 17.7 nm, whereas when a buried film is formed, the minimum line width is about 15.6 nm. This result also shows that the inorganic resist pattern can be prevented from collapsing according to this embodiment.

In addition, in this embodiment, the wafer processing apparatus 1 executes a process for reducing the thickness of the embedded film, so the burden of removing the embedded film outside the wafer processing apparatus 1 can be reduced. For example, when etching the base film using an inorganic resist pattern as a mask in an etching apparatus outside the wafer processing apparatus 1, the burden of removing the embedded film in the external etching apparatus can be reduced.

Furthermore, in this embodiment, the filling liquid is supplied to the wafer W while it is still wet. In this case, it is possible to prevent the inorganic resist pattern from collapsing due to the surface tension of the processing liquid, such as the developer, before the filling liquid is supplied.

Second Embodiment
FIG. 8 is a diagram showing an outline of the internal configuration on the rear side of a wafer processing apparatus as a substrate processing apparatus according to the second embodiment.

According to an experiment conducted by the present inventors, when an undercoat film before forming an inorganic resist film (specifically, a tin-containing resist film) is irradiated with ultraviolet light, the incidence of pattern collapse is lower when the undercoat film is irradiated in an oxygen-containing atmosphere (specifically, in an air gas atmosphere) than when the undercoat film is irradiated in a nitrogen atmosphere.
This is believed to be because irradiation with ultraviolet light in an oxygen-containing atmosphere increases the number of OH groups on the surface of the base film, i.e., makes the surface of the base film more hydrophilic, resulting in the lower parts of the convex parts of the inorganic resist pattern becoming wider and improving the adhesion between the inorganic resist pattern and the base film.

The wafer processing apparatus 1A in FIG. 8 is based on the experimental results described above, and in addition to the configuration of the wafer processing apparatus 1 shown in FIG. 1 etc., includes a UV irradiation module 41 as another ultraviolet irradiation section. The UV irradiation module 41 irradiates the wafer W with ultraviolet rays, similar to the aforementioned UV irradiation module 52, and more specifically, irradiates the entire upper surface of the wafer W, i.e., the entire surface, with ultraviolet rays in an oxygen-containing atmosphere.

The UV irradiation modules 41 are arranged in multiple rows in the vertical and width directions (Y direction in the figure) in the second block G2A of the processing block BL1A of the processing station 11A, similar to the heat treatment modules 40. The number and arrangement of the UV irradiation modules 41 can also be selected arbitrarily.

<Example of Processing by Wafer Processing Apparatus 1A>
FIG. 9 is a flow chart showing main steps of an example of processing by the wafer processing apparatus 1A.
In the processing by the wafer processing apparatus 1A, for example, as shown in FIG. 9, after the base film forming step S2 in the processing by the wafer processing apparatus 1 is performed, the entire surface of the wafer W, i.e., the entire surface of the base film, is irradiated with ultraviolet light.

Specifically, the wafer W is transported to the UV irradiation module 41 by the transport module R2, and the entire surface of the wafer W is irradiated with ultraviolet rays in an oxygen-containing atmosphere (specifically, for example, an atmospheric gas atmosphere). As a result, the entire surface of the base film on the wafer W is made hydrophilic by ozone generated by the ultraviolet rays in the surrounding atmosphere. In other words, the ozone increases the number of OH groups on the surface of the base film on the wafer W.

Then, steps S3 and onwards are carried out in the processing by the wafer processing device 1.

<Main Effects of the Second Embodiment>
In this embodiment, before forming an inorganic resist film on the undercoat film, the undercoat film is irradiated with ultraviolet light in an oxygen-containing atmosphere, so that the surface of the undercoat film on the wafer W can be made hydrophilic, as described above. Therefore, when an inorganic resist pattern is formed on the undercoat film, the lower part of the convex part of the pattern can be made wider. Therefore, the adhesion between the inorganic resist pattern and the undercoat film can be improved, and pattern collapse can be further suppressed.

Third Embodiment
FIG. 10 is a diagram showing an outline of the internal configuration of a front side of a wafer processing apparatus as a substrate processing apparatus according to the third embodiment.

According to experiments conducted by the present inventors, when water or ozone water was supplied to an undercoat film prior to the formation of an inorganic resist film (specifically, a tin-containing resist film), the occurrence rate of pattern collapse was lower than when water or ozone water was not supplied.
This is believed to be because the supply of water or ozone water increases the number of OH groups on the surface of the base film, i.e., makes the surface of the base film more hydrophilic, resulting in the lower parts of the convex parts of the inorganic resist pattern becoming wider and improving the adhesion between the inorganic resist pattern and the base film.

The wafer processing apparatus 1B in FIG. 10 is based on the experimental results described above, and in addition to the configuration of the wafer processing apparatus 1 shown in FIG. 1 etc., includes a hydrophilization module 33. The hydrophilization module 33 supplies a liquid for hydrophilizing the base film (hereinafter, hydrophilization liquid) to the wafer W as a processing liquid. The hydrophilization liquid is, for example, water or ozone water.

The hydrophilization modules 33 are arranged in a row in the width direction (Y direction in the drawing) in the first block G1B of the processing block BL1B of the processing station 11B, similar to the developing modules 30, etc. The number and arrangement of the hydrophilization modules 33 can also be selected arbitrarily.
In the hydrophilizing module 33, similarly to the developing module 30, a hydrophilizing liquid is applied onto the wafer W by, for example, spin coating.
The configuration of the hydrophilic module 33 is similar to that of the developing module 30. However, the hydrophilic module 33 and the developing module 30 are different in the number of ejection nozzles that eject the treatment liquid and the treatment liquid supplied from the ejection nozzles.

<Example of Processing by Wafer Processing Apparatus 1B>
FIG. 11 is a flow chart showing main steps of an example of processing by the wafer processing apparatus 1B.
In the processing by the wafer processing apparatus 1A, for example, as shown in FIG. 11, after the base film forming step S2 in the processing by the wafer processing apparatus 1 is performed, a hydrophilization process of the base film is performed using a hydrophilization liquid.

Specifically, the wafer W is transported to the hydrophilization module 33 by the transport module R2, and the hydrophilization liquid is supplied to the surface of the rotating wafer W. As a result, the entire surface of the base film on the wafer W is hydrophilized by the OH radicals in the hydrophilization liquid. In other words, the OH radicals in the hydrophilization liquid increase the number of OH groups on the entire surface of the base film on the wafer W.

Then, steps S3 and onwards are carried out in the processing by the wafer processing device 1.

<Main Effects of the Third Embodiment>
In this embodiment, before forming an inorganic resist film on the undercoat film, hydrophilic water such as water or ozone water is supplied to the undercoat film, so that the surface of the undercoat film on the wafer W can be made hydrophilic, as described above. Therefore, when a resist pattern is formed on the undercoat film, the lower part of the convex part of the resist pattern can be made wider. Therefore, the adhesion between the resist pattern and the undercoat film can be improved.

(Modification of the third embodiment)
In the above, the undercoat film is exposed to an ozone atmosphere by supplying ozone water as hydrophilic water to the undercoat film. The method of exposing the undercoat film to the ozone atmosphere is not limited to this, and may be, for example, a method of supplying a gas containing ozone to the undercoat film, specifically, a method of spraying a gas containing ozone from a two-fluid nozzle to the undercoat film.
In the above, the hydrophilization module 33 and the resist coating module 32 are configured as separate modules, but they may be integrated into a single module. In this case, it is preferable that the integrated module has a hybrid cup capable of separately collecting the hydrophilization water and the resist liquid.

Fourth Embodiment
Fig. 12 is an explanatory diagram showing an outline of the internal configuration of a wafer processing apparatus as a substrate processing apparatus according to the fourth embodiment, and Fig. 13 is a diagram showing an outline of the internal configuration of the front side of the wafer processing apparatus shown in Fig. 12.

The wafer processing apparatus 1D of FIGS. 12 and 13 differs from the wafer processing apparatus 1 of FIGS. 1 to 3 in the following points.
The wafer processing apparatus 1D has a second block G2A including a UV irradiation module 41, similar to the wafer processing apparatus 1B of FIG.
The wafer processing apparatus 1D has a measurement module 53.
In the wafer processing apparatus 1D, the developing module 30D has multiple types of developer nozzles that have different usage patterns when ejecting the developer, and is configured to be able to switch the developer to be ejected from multiple types of developers that have different solubilities of inorganic-containing resist.
In the wafer processing apparatus 1D, the program storage unit of the control unit 3D further stores a program including a command for a determination sequence related to pattern collapse, which will be described later.

The measurement module 53 measures the state of the inorganic resist pattern formed by the wafer processing apparatus 1D. Specifically, the measurement module 53 measures the state of the inorganic resist pattern under atmospheric pressure after the thickness of the filling film has been reduced by the UV irradiation module 52. The measurement by the measurement module 53 is performed using, for example, a scatterometry method.
The measurement results by the measurement module 53 are output to the control unit 3D.

The measurement module 53 is provided, for example, in the transfer block BL2D of the processing station 11B. Specifically, for example, as shown in FIG. 13, a plurality of measurement modules 53 are provided so as to overlap the UV irradiation modules 52 in the vertical direction.

<Example of Determination Sequence for Pattern Collapse by Wafer Processing Apparatus 1D>
FIG. 14 is a flow chart showing an example of a determination sequence related to pattern collapse (including pattern peeling) by the wafer processing apparatus 1D.
In the above-mentioned determination sequence by the wafer processing apparatus 1D, determinations related to the pattern collapse of the inorganic resist, including determination of processing conditions related to the filling film, are made.

In the above-mentioned determination sequence by the wafer processing apparatus 1D, for example, first, as shown in FIG. 14, the processing conditions for the embedded film are determined (step S51). Specifically, the condition determination wafer W is subjected to a process similar to that by the wafer processing apparatus 1 including the embedding process step of step S8 described with reference to FIG. 6, and a metal-containing resist pattern is formed. In addition, the state of the formed metal-containing resist pattern is measured, and the processing conditions for the embedded film are determined based on the measurement results. The processing conditions for the embedded film are, for example, the drying conditions of the embedding liquid in the embedding process step of step S8. In the case where the type and concentration of the embedding liquid can be changed in the developing module 30D, the processing conditions for the embedded film may be the type and concentration of the embedding liquid.

More specifically, in step S51, for example, first, each process of steps S1 to S11 in FIG. 6 is performed on the condition setting wafer W. At this time, in the exposure process of step S5, exposure is performed as follows. That is, when the surface of the wafer W is divided into a plurality of regions and each region is a divided exposure region, exposure is performed under different exposure conditions (specifically, focus and exposure amount) for each divided exposure region. At this time, the processing conditions for the filling process of step S8 are selected from pre-stored candidates. Furthermore, at this time, after the filling film thickness reduction process of step S10 and before the unloading of step S11, the state of the inorganic resist pattern is measured by the measurement module 53 using a scatterometry method for each of the divided exposure regions.

Next, the control unit 3D determines whether or not a defect such as pattern collapse has occurred based on the measurement results obtained by the measurement module 53 using the scatterometry method for each of the divided exposure regions.
Specifically, the control unit 3D calculates, for each divided exposure area, the goodness of fit (GOF) between the measurement result obtained by the measurement module 53 using the scatterometry method and a pre-stored model corresponding to the target pattern dimensions. Then, the control unit 3D determines that a pattern collapse defect has occurred in a divided exposure area where the goodness of fit is less than a predetermined threshold value, and determines that a pattern collapse defect has not occurred in a divided exposure area where the goodness of fit is equal to or greater than the predetermined threshold value.

Then, if the number of divided regions where no pattern collapse defects have occurred is equal to or greater than a predetermined threshold value, i.e., if a predetermined margin can be ensured in the exposure conditions for forming a desired inorganic-containing resist pattern, the candidate processing conditions used in the embedding processing step of step S8 for the condition setting wafer W are determined to be the processing conditions for the same process for the actual wafer W.

On the other hand, if the number of divided regions where no pattern collapse defects have occurred is less than a predetermined threshold, that is, if a predetermined tolerance cannot be ensured for the exposure conditions for forming a desired inorganic-containing resist pattern, the above-mentioned steps are repeated until the tolerance can be ensured. However, each time the steps are repeated, the processing conditions used in the embedding processing step of step S8 are changed to other pre-stored candidates.

Note that there may be cases where the number of divided regions free of pattern collapse defects is equal to or greater than a predetermined threshold value among the prestored candidates for processing conditions to be used in the embedding process of step S8. In other words, there may be cases where, within the predefined range of processing conditions for the embedding process of step S8, a predetermined margin cannot be ensured for the exposure conditions for forming a desired inorganic-containing resist pattern (NO in step S52 of FIG. 14). In this case, the type of developer is further determined (step S53).

Specifically, the condition setting wafer W is subjected to a process similar to that performed by the wafer processing apparatus 1, including the embedding process step S8, as described with reference to FIG. 6, to form a metal-containing resist pattern. In addition, the state of the formed metal-containing resist pattern is measured, and the type of developer is determined based on the measurement results.

More specifically, in step S53, for example, first, the conditions setting wafer W is subjected to each process of steps S1 to S11 in FIG. 6 and measurement by the measurement module 53, similar to step S51. At this time, the type of developer used in the development process of step S7 is selected from pre-stored candidates. Also, at this time, the embedding process process of step S8 may be performed based on the candidate with the highest degree of suitability in step S51, among the pre-stored candidates for processing conditions.

Next, similar to step S51, the control unit 3D determines whether or not a pattern collapse defect has occurred for each of the divided exposure regions based on the measurement results obtained by the measurement module 53 using the scatterometry method.

Then, if the number of divided areas in which no pattern collapse defects have occurred is equal to or greater than a predetermined threshold, the type of developer used is determined to be the type of developer used for the actual wafer W.

On the other hand, if the number of divided regions where no pattern collapse defects occur is less than a predetermined threshold, that is, if a predetermined margin cannot be secured for the exposure conditions for forming a pattern of the inorganic-containing resist in the desired state, the above-mentioned steps are repeated until the margin can be secured. However, each time the steps are repeated, the type of developer used in step S7 is changed to another type stored in advance. At this time, the type of developer used in the development step of step S7 may be changed according to the above-mentioned compatibility. Specifically, if the compatibility is somewhat small and there is a pattern collapse defect, the developer is changed to a type with a smaller hydrogen bond term of the Hansen solubility parameter proportional to the solubility of the negative inorganic resist, and if the compatibility is very small and there are many pattern collapse defects, the developer may be changed to a type with an even smaller hydrogen bond term. The hydrogen bond term of the Hansen solubility parameter is associated with the type of developer and stored in advance in a storage unit (not shown).

Note that there may be cases where the number of divided regions in which pattern collapse defects do not occur is equal to or exceeds a predetermined threshold value among the types of developer stored in advance. In other words, there may be cases where the predetermined tolerance cannot be ensured for the exposure conditions for forming a desired inorganic-containing resist pattern among the types of developer preset (NO in step S54 in FIG. 14). In this case, similar to the process described using FIG. 9, after the base film formation process and before the resist film formation process, it is determined that an ultraviolet ray irradiation process is performed on the base film, and the processing conditions for the ultraviolet ray irradiation process are further determined (step S55). The processing conditions determined here may be, for example, the exposure amount per unit time in the ultraviolet ray irradiation process, or may also be the exposure time.

Specifically, in step S55, for example, first, the respective processes of steps S1 to S11 in FIG. 6 and measurement by the measurement module 53 are performed on the condition determination wafer W in the same manner as in step S53, and step S21 in FIG. 9 is performed between steps S2 and S3. At this time, the ultraviolet irradiation process of step S21 is performed based on the candidate selected from among the candidates of processing conditions stored in advance. In addition, the type of developer used at this time may be the one that has the highest degree of suitability described above in step S53 among the candidates of the type of developer stored in advance.

Next, the control unit 3D determines whether or not a pattern collapse defect has occurred for each of the divided exposure regions based on the measurement results obtained by the measurement module 53 using the scatterometry method.

If the number of divided regions in which no pattern collapse defects have occurred is equal to or greater than a predetermined threshold, the candidate processing conditions used in the ultraviolet irradiation process of step S21 for the condition setting wafer W are determined to be the processing conditions for the same process for the actual wafer W.

On the other hand, if the number of divided regions where no pattern collapse defects have occurred is less than a predetermined threshold, that is, if a predetermined tolerance cannot be ensured for the exposure conditions for forming a desired inorganic-containing resist pattern, the above-mentioned steps are repeated until the tolerance can be ensured. However, each time the steps are repeated, the processing conditions used in the ultraviolet irradiation step of step S21 are changed to other pre-stored candidates.

Note that there may be cases where the number of divided regions in which pattern collapse defects do not occur is equal to or exceeds a predetermined threshold value among the candidates for processing conditions to be used in the ultraviolet irradiation process of step S21 that are stored in advance. In other words, within the range of processing conditions previously set for the ultraviolet irradiation process of step S21, there may be cases where a predetermined margin cannot be secured for the exposure conditions for forming a desired inorganic-containing resist pattern (if NO in step S56 of FIG. 14). In this case, the type of developer nozzle is further determined (step S57). Since the developer nozzle has a different supply form for the developer depending on the type, the impact of the supplied developer on the inorganic resist pattern differs for each nozzle, so changing the type of developer nozzle can suppress pattern collapse.

Specifically, in step S57, for example, first, the respective processes of steps S1 to S11 in FIG. 6 and measurement by the measurement module 53 are performed on the condition determination wafer W in the same manner as in step S55, and step S21 in FIG. 9 is performed between steps S2 and S3. At this time, the nozzle for the developing solution used in the development process of step S7 is selected from pre-stored candidates. Also, at this time, the ultraviolet irradiation process of step S21 may be performed based on the candidate with the highest degree of suitability in step S55 among the pre-stored candidates for processing conditions.

Next, similar to step S51, the control unit 3D determines whether or not a pattern collapse defect has occurred for each of the divided exposure regions based on the measurement results obtained by the measurement module 53 using the scatterometry method.

Then, if the number of divided areas in which no pattern collapse defects have occurred is equal to or greater than a predetermined threshold, the type of developer nozzle used is determined to be the type of developer nozzle to be used for the actual wafer W.

On the other hand, if the number of divided regions where no pattern collapse defects have occurred is less than a predetermined threshold, that is, if a predetermined tolerance cannot be ensured for the exposure conditions for forming a desired inorganic-containing resist pattern, the above-mentioned steps are repeated until the tolerance can be ensured. However, each time the steps are repeated, the type of developer nozzle used in step S7 is changed to another type that has been stored in advance.

Next, similar to step S51, the control unit 3D determines whether or not a pattern collapse defect has occurred for each of the divided exposure regions based on the measurement results obtained by the measurement module 53 using the scatterometry method.

Then, if the number of divided areas in which no pattern collapse defects have occurred is equal to or greater than a predetermined threshold, the candidate type of developer nozzle used for the condition setting wafer W is determined to be the developer nozzle to be used for the actual wafer W.

On the other hand, if the number of divided regions where no pattern collapse defects have occurred is less than a predetermined threshold, that is, if a predetermined tolerance cannot be ensured for the exposure conditions for forming a desired inorganic-containing resist pattern, the above-mentioned steps are repeated until the tolerance can be ensured. However, each time the steps are repeated, the type of developer nozzle used in step S7 is changed to another type that has been stored in advance.

Note that there may be cases where the number of divided areas in which pattern collapse defects do not occur is equal to or exceeds a predetermined threshold value among the prestored types of developer nozzles. In other words, there are cases where the prestored types of developer nozzles cannot ensure a predetermined margin in the exposure conditions for forming a desired inorganic-containing resist pattern (NO in step S58 of FIG. 14). In such cases, for example, a notification is issued that the wafer processing device 1D was unable to complete the determination sequence related to pattern collapse (step S59). This notification is issued, for example, via a display device such as a liquid crystal display.

When the determination sequence for pattern collapse by the wafer processing device 1D is completed, the actual wafer W is processed based on the processing conditions determined by the determination sequence.

(Modification of the fourth embodiment)
In the above, the "desired state" in the "pattern of the inorganic-containing resist in a desired state" means a state in which the defect of pattern collapse does not occur. The above-mentioned "desired state" may mean a state in which the defect of pattern collapse does not occur, and further, a state in which the desired line width is obtained or a state in which the inorganic-containing resist pattern is appropriately removed by a removal process.
The line width of the pattern of the inorganic-containing resist is calculated by the control unit 3D based on the measurement results obtained by the measurement module 53.
In addition, whether or not the inorganic-containing resist pattern is in a state where it can be appropriately removed by the removal process is determined, for example, as follows: That is, after the inorganic-containing resist pattern is removed by an etching device outside the wafer processing device 1A, the state of the wafer W is measured by a measuring device outside the wafer processing device 1A, and the measurement result is output to the control unit 3D. Then, the control unit 3D determines, based on the measurement result, whether or not the inorganic-containing resist pattern is in a state where it can be appropriately removed by the removal process.

In addition, in the above example, multiple different types of development nozzles were provided in each development module 30D, but each type of development nozzle may be provided in a different development module.

In the above example, the processing conditions for the embedded film determined in the fourth embodiment were the processing conditions in the development process in step S8, but they may also be the processing conditions in the post-bake processing process in step S9 (e.g., the temperature and heating time of the wafer W) or the processing conditions in the PEB processing process in step S6 (e.g., the temperature and heating time of the wafer W).

The part of the control unit 3D that makes decisions regarding at least pattern collapse may be provided in a control device that collectively controls multiple wafer processing devices of the same type as the wafer processing device 1D.

Fifth Embodiment
FIG. 15 is an explanatory diagram showing an outline of the internal configuration of a wafer processing apparatus as a substrate processing apparatus according to the fifth embodiment.

A wafer processing apparatus 1E in FIG. 15 includes a wet processing section 2, a dry processing section 4, a first intermediary transport section 5, and a second intermediary transport section 6. The wafer processing apparatus 1E in FIG.
The wet processing unit 2 includes a cassette station 10E, a processing station 11E, and an interface station 12. The processing station 11 of the wafer processing apparatus 1 described above has one processing block BL1. In contrast, the wafer processing apparatus 1E of Fig. 15 has a plurality of processing blocks BL3 and BL4 (two in the illustrated example) disposed in the processing station 11E along the width direction (Y direction in the figure) with a relay block BL5 sandwiched therebetween. The processing block BL3 is located on the cassette station 10 side, and the processing block BL4 is located on the interface station 12E side.

Each of the processing blocks BL3 and BL4 is configured in substantially the same manner as the processing block BL1 shown in FIG. 1 and the like. Specifically, each of the processing blocks BL3 and BL4 has, for example, a first block G1 on the front side (negative side in the X direction in the figure). In the first block G1, for example, a development module 30, a base film forming module 31, and a resist coating module 32 are arranged in a row along the width direction (Y direction in the figure). In addition, each of the processing blocks BL3 and BL4 has, for example, a second block G2 on the rear side (positive side in the X direction in the figure). In the second block G2, for example, a heat treatment module 40 is arranged in a row along the vertical direction and width direction (Y direction in the figure).

The number of development modules 30 arranged in the width direction may be the same or different between processing block BL3 and processing block BL4. The same applies to the base film forming module 31, resist coating module 32, and heat treatment module 40.

The processing blocks BL3 and BL4 are provided with transfer regions R7 and R8 extending in the width direction between the first block G1 and the second block G2. Transfer modules R9 and R10 for transferring wafers W are disposed in the transfer regions R7 and R8, respectively.

The transfer module R9 can transfer the wafer W to the surrounding liquid treatment modules, the heat treatment module 40, the transfer module 51 of the transfer tower 50, and the transfer module of the transfer tower 54 described below. The transfer module R10 can transfer the wafer W to the surrounding liquid treatment modules, the heat treatment module 40, the transfer module of the transfer tower 54 described below, and the transfer module 61 of the transfer tower 60.

A transfer tower 54 is provided in the center of the relay block BL5 in the depth direction (X direction in the figure). A plurality of transfer modules (not shown) are provided vertically stacked in the transfer tower 54. A transfer module R11 is provided on the rear side of the transfer tower 54 (positive side in the X direction in the figure). The transfer module R11 transfers wafers W between the plurality of transfer modules of the transfer tower 54 and a transfer module 55 described below.

In this example, a transfer module 55 is provided at the rear side of the transport module R11 (the positive side in the X direction in the figure) for transfer between the first relay transport section 5 and the wet processing section 2.

In addition, in this example, a transfer module 56 is provided at the rear side of the transfer module R5 (the positive side in the X direction in the figure) for transfer between the second relay transfer section 6 and the wet processing section 2. In this example, the transfer module R5 can transfer the wafer W between the multiple transfer modules 51 and transfer module 56 of the transfer tower 50.

The dry processing section 4 has a load lock station 200, a processing station 201, and a load lock module 202.

The load lock station 200 is provided with a load lock module 210. The load lock modules 210 and 202 are each configured to be able to switch the internal atmosphere between a reduced pressure atmosphere and an atmospheric pressure atmosphere.

The processing station 201 has a vacuum transfer chamber 220, a processing module 221, and a heat treatment module 222.

The vacuum transfer chamber 220 consists of a sealable housing, the interior of which is kept in a reduced pressure state (vacuum state).

Processing module 221 is a dry processing module that performs the same type of wafer processing as the wet processing module of wet processing unit 2, but in a dry manner; specifically, it performs the development processing performed by development module 30 of wet processing unit 2 in a dry manner. The dry method is a method that uses gas, and more specifically, a method that uses gas under reduced pressure. It can be said that dry processing achieves the desired effect mainly through gas, while wet processing achieves the desired effect mainly through liquid.

The thermal treatment module 222 performs a post-bake process as a heating process on the wafer W after the dry development process.

In addition, a transfer module 223 for transferring the wafer W is provided inside the vacuum transfer chamber 220. The transfer module 223 has a transfer arm 223a that is movable, for example, in the width direction (Y direction in the figure) and in a direction around the vertical axis. The transfer module 223 holds the wafer W on the transfer arm 223a and can transfer the wafer W between the processing module 221, the heat treatment module 222, and the load lock modules 210 and 211.

The first relay transport unit 5 and the second relay transport unit 6 each transport the wafer W between the wet processing unit 2 and the dry processing unit 4.

The first relay transfer section 5 has a transfer path 230 at a position adjacent to the relay block BL5 in the depth direction (X direction in the figure). A transfer module 231 is provided on the transfer path 230. The transfer module 231 transfers the wafer W between the delivery module 55 and the load lock module 210.

The second relay transfer section 6 has a transfer path 240 at a position adjacent to the transfer block BL2E in the depth direction (X direction in the figure). A transfer module 241 is provided on the transfer path 240. The transfer module 231 transfers the wafer W between the transfer module 56 and the load lock module 202.

<Example of Processing by Wafer Processing Apparatus 1E>
Next, an example of processing by the wafer processing apparatus 1E will be described.
In one example of processing by the wafer processing apparatus 1E, for example, first, each process of step S1 to step S8 in Fig. 6 is performed. As a result, for example, an inorganic resist pattern having a width larger than a target line width is formed on the wafer W, and a buried film is also formed.

Next, a second PEB process is performed by the heat treatment module 40. This promotes cross-linking of the inorganic resist pattern, and hardens the inorganic resist pattern.
Then, step S10 in FIG. 6 is performed, and the filling film is removed by the UV irradiation module 52.
Thereafter, an additional dry development process is performed by the process module 221 of the dry processing section 4 to narrow the line width of the inorganic resist pattern, thereby forming an inorganic resist pattern having a target line width.

(Modification of the fifth embodiment)
The UV irradiation module 52 may be provided in the relay block BL5 instead of or in addition to the transfer block BL2E.

<Other Modifications>
In the above example, the entire filling film is removed when the thickness of the filling film is reduced, but the filling film may be left at the bottom between adjacent convex portions in the inorganic resist pattern, for example, 10% or more of the height of the convex portions in the inorganic resist pattern may be left.
In this case, the filling film F remaining between the convex portions RP1 is removed together with the base film U when the base film U is etched using an etching gas with the inorganic resist pattern as a mask. It is preferable that the filling film F has a lower etching resistance than the base film U against an etching gas generally used for the base film U.
By leaving a portion of the filling film remaining as described above, collapse of the inorganic resist pattern can be suppressed until the etching of the base film U.
In this case, when determining the processing conditions for the filling film in the fourth embodiment, the amount by which the thickness of the filling film F is reduced may be determined as the processing conditions for the filling film.

In the above example, the developing section that develops the wafer W and the embedding section that performs the embedding process on the wafer W are combined into one module, but each may also be configured as a separate module.

In addition, in the UV irradiation module 52 for removing the buried film, the wafer W may be irradiated with ultraviolet rays while being heated. In this case, the UV irradiation module 52 has a hot plate (not shown) on which the wafer W is placed, similar to the heat treatment module 40. The UV irradiation module 52 and the heat treatment module 40 may be integrated into the same module. In this case, in a module that performs both a heating process (e.g., the post-bake process in the example of FIG. 6 or the second PEB process in the fifth embodiment) performed immediately before the ultraviolet irradiation process and an ultraviolet irradiation process, the heating process immediately before the ultraviolet irradiation process and the ultraviolet irradiation process may be performed consecutively. Specifically, in the above module, after the heating process immediately before the ultraviolet irradiation process is completed, ultraviolet rays may be irradiated toward the wafer W on the hot plate while continuing to heat the wafer W with the hot plate.

In the above examples, the state of the inorganic resist pattern was measured using a scatterometry method. Alternatively, the surface of the inorganic resist pattern may be imaged using an imaging module, and the state of the inorganic resist pattern may be detected/measured based on the imaging results.

According to the results of repeated tests by the inventors, when the hydrogen bond term of the Hansen solubility parameter of the treatment liquid is large, the solubility of the negative inorganic resist in the treatment liquid is higher than when the hydrogen bond term is small, that is, the solubility is higher in a polar treatment liquid than in a non-polar treatment liquid. This is because, when a negative inorganic resist is exposed to light, a component having a hydroxyl group in the resist, which is generated by the removal of a ligand, is more likely to dissolve in a treatment liquid having a small hydrogen bond term of the Hansen solubility parameter, that is, is more likely to dissolve in a treatment liquid having a high polarity.
In addition, according to repeated testing by the present inventors, when the hydrogen bond term of the Hansen solubility parameter of the treatment liquid used for development is small, the pattern of the negative inorganic resist is less likely to collapse (including peeling off) than when it is large, that is, when the treatment liquid used for development is non-polar, the collapse is less likely to occur than when it is polar. The reasons for this are considered to be as follows.

In the negative inorganic resist film after the pattern exposure, there are unexposed regions with zero (or close to zero) exposure amount and exposed regions with sufficient exposure amount, and there is an intermediate region between the unexposed region and the exposed region with less exposure amount than the exposed region. In the intermediate exposure region, due to the nature of the exposure light (specifically, EUV light), the exposure amount at the back side far from the film surface is less than the exposure amount at the film surface side. Therefore, in the intermediate exposure region, the amount of condensation reaction of the negative inorganic resist is also less at the back side far from the film surface, and the degree of solidification is also low.
Therefore, when a polar processing solution in which the negative inorganic resist has high solubility is used for development, more resist is removed from the inner side of the intermediate exposure region of the negative inorganic resist than from the film surface side, and the base of the resist pattern becomes thinner. As a result, it is believed that the pattern is more likely to collapse or peel off.
On the other hand, when a non-polar processing solution with low solubility for negative inorganic resist is used for development, the amount of resist removed is almost the same between the back side of the intermediate exposure region of the negative inorganic resist and the film surface side, so the base of the resist pattern is unlikely to become thin. As a result, it is believed that the pattern is unlikely to collapse or peel off.

However, if the processing liquid used for development is non-polar, the solubility of negative-type inorganic resist in the processing liquid is low, so there is a risk that the inorganic resist that should be removed by development will not be completely removed, i.e., there is a risk that residues will be left behind or that bridge defects will occur.

In consideration of these, the embedding liquid may contain a polar processing liquid, i.e., a polar solvent, as a secondary component, which is a component that improves the solubility of the inorganic resist in the embedding liquid. Specifically, the main component of the embedding liquid may be an organic polymer solution using a non-polar organic solvent as a solvent, and the secondary component of the embedding liquid may be a polar processing liquid.
As a result, when a non-polar processing liquid is used as a developer to suppress pattern collapse, etc., the inorganic resist that may remain due to the use of the non-polar processing liquid can be dissolved in the filling liquid during filling. Therefore, it is possible to suppress the occurrence of residues and bridges while suppressing pattern collapse and peeling. The inorganic resist dissolved in the filling liquid is removed together with the filling film formed when the filling liquid is dried and removed.

The polar processing liquid contained as a secondary component in the embedding liquid is, for example, N-propanol, acetic acid, water, ethyl lactate, acetone, or a mixture of two or more of these.
In the case where the main component of the embedding liquid (specifically, the organic polymer solution) and the polar processing liquid are not miscible with each other, the embedding liquid may further contain a dispersant as a secondary component.
The dispersing agent of the embedding liquid includes, as a solvent, for example, isopropyl alcohol, ethanol, normal propyl alcohol (NPA), methyl isobutyl carbinol (MIBC), propylene glycol monomethyl ether (PGME), cyclohexane, or a mixture of two or more of these. The dispersing agent also includes, as a surfactant, for example, a nonionic surfactant, specifically, sorbitan monooleate, glycerol α-monooleate, polyethylene glycol sorbitan fatty acid ester, polyethylene glycol linear alkyl ether, linear alkyl-added polyethylene glycol phenyl ether, branched alkyl-added polyethylene glycol phenyl ether, acetylene glycol, or a combination thereof. The dispersing agent of the embedding liquid may include, as a surfactant, an anionic surfactant, specifically, sodium laurate, sodium stearate, sodium oleate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, or a combination thereof.

For example, the ratio of the main component in the embedding liquid is 80% to 95%, and the ratio of the subcomponent in the embedding liquid (polar processing liquid alone or the total of polar processing liquid and dispersant) is 5% to 15%.
The organic polymer solution, which is the main component of the embedding liquid, is dissolved in PGMEA, which accounts for 80% to 90% of the embedding liquid, and the organic polymer is dissolved in PGMEA, which accounts for 5% of the embedding liquid.

The developer used together with the embedding liquid containing the polar processing liquid as a sub-component is non-polar, specifically, the hydrogen bond term of the Hansen solubility parameter is 10 MPa ^1/2 or less, more specifically, PGMEA, 2-heptanone, cyclohexane, normal butyl alcohol, acetone, or a mixture of two or more of these.

Furthermore, the inventors have found through repeated testing that when water is added to a non-polar developer, the inorganic resist pattern is even less likely to collapse or peel off.
Based on the test results, water may be added to a non-polar developer used together with an embedding liquid containing a polar processing liquid as a secondary component. That is, the developer may be a mixture of a non-polar processing liquid as a main component and water as a secondary component. In addition, when the non-polar processing liquid as a main component of the developer is not mixed with water as a secondary component of the developer, a dispersant may be further included as a secondary component of the developer.

When the developer is a mixed solution containing water as described above, the ratio of the subcomponents (water alone or the sum of water and dispersant) in the developer is set to, for example, 20% or less, specifically, 10% or more and 20% or less, so that the developer does not exhibit high polarity, i.e., so that the solubility of the inorganic resist in the developer does not become high. Also, the ratio of water in the developer may be determined so that the hydrogen bond term of the Hansen solubility parameter of the developer, which is a mixed solution with water, is 11 MPa ^1/2 or less.

Furthermore, when the developer is a mixed solution containing water, the non-polar processing solution as the main component of the developer is, for example, one having a hydrogen bond term of the Hansen solubility parameter of 10 MPa ^1/2 or less, and specifically, PGMEA, 2-heptanone, cyclohexane, normal butyl alcohol, acetone, or a mixed solution of two or more of these is used.
The dispersant contained in the developer as a minor component may be, for example, the same as the non-polar processing liquid as the main component of the developer, that is, the hydrogen bond term of the Hansen solubility parameter is 10 MPa ^1/2 or less. The dispersant contained in the developer as a minor component may be, for example, the same as the activator used in the dispersant contained in the embedding liquid as a minor component.

When the development process is carried out by supplying the wafer W with a developer whose components have been adjusted as described above, the development process may be completed with the bottoms of the convex parts of the pattern locally thickened, or with a resist film that is thin enough relative to the convex parts so as to connect the bottoms of multiple convex parts, thereby preventing the pattern from collapsing. The thickness of the resist film that is thin enough relative to the convex parts may be, for example, less than half the height of the convex parts of the pattern.

The wafer processing apparatus disclosed herein is not limited to the configuration and operation described above. In the above embodiment, the wafer processing apparatus is directly connected to the exposure apparatus, and the wafer W is transferred between the interface station 12 and the exposure apparatus, but the wafer processing apparatus does not have to be directly connected to the exposure apparatus. In that case, for example, after the wafer W is subjected to necessary processing in the processing station 11 of the wafer processing apparatus, it is transferred from the cassette station 12 to the outside of the wafer processing apparatus and then transferred to the exposure apparatus. In addition, among the devices (modules) listed as those that perform processing on the wafer W, those that are not required may not be provided in the wafer processing apparatus, or processing may not be performed in those devices (modules).

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the components of the above-described embodiments may be combined in any manner. Such combinations will naturally provide the functions and effects of each of the components in the combination, as well as other functions and effects that will be apparent to those skilled in the art from the description in this specification.

Furthermore, the effects described in this specification are merely descriptive or exemplary and are not limiting. In other words, the technology disclosed herein may achieve other effects that are apparent to a person skilled in the art from the description in this specification, in addition to or in place of the above effects.

Note that the following configuration examples also fall within the technical scope of the present disclosure.
(1) a step of developing a substrate having an inorganic resist film formed on an undercoat film and having been subjected to an exposure treatment, using a developer to form a pattern of the inorganic resist;
supplying a filling liquid to the developed substrate to fill spaces between adjacent convex portions in the pattern;
drying the filled embedding liquid to form an embedding film on the substrate;
and reducing a thickness of the buried film by ultraviolet light.
(2) The substrate processing method according to (1), wherein the base film and the filling film are the same type of organic film.
(3) The substrate processing method according to (1) or (2), further comprising a step of irradiating the undercoat film with ultraviolet light in an oxygen-containing atmosphere before the inorganic resist coating is formed on the undercoat film.
(4) The substrate processing method according to any one of (1) to (3), further comprising a step of supplying water to the undercoat film or exposing the undercoat film to an ozone atmosphere before the inorganic resist coating is formed on the undercoat film.
(5) The substrate processing method according to any one of (1) to (4), wherein the step of reducing the thickness of the filling film includes removing the filling film so that the filling film remains at the bottom between the patterns.
(6) measuring a state of the pattern after the step of reducing the thickness of the filling film;
The substrate processing method according to any one of (1) to (5), further comprising: a step of making a decision regarding pattern collapse, including a decision of processing conditions regarding the buried film, based on a measurement result in the measuring step.
(7) The substrate processing method according to any one of (1) to (6), wherein the filling liquid contains, as a sub-component, a component that improves solubility of the inorganic resist in the filling liquid.
(8) A readable computer storage medium storing a program that runs on a computer of a control unit that controls a substrate processing apparatus so as to cause the substrate processing apparatus to execute a substrate processing method, the program comprising:
The substrate processing method includes:
a step of developing the substrate, which has an inorganic resist film formed on the undercoat film and has been subjected to an exposure treatment, with a developer to form a pattern of the inorganic resist;
supplying a filling liquid to the developed substrate to fill spaces between adjacent patterns, and then drying the filling liquid to form a filling film on the substrate;
and reducing the thickness of the embedding film with ultraviolet light.
(9) A substrate processing apparatus for processing a substrate, comprising:
a developing section for developing the substrate with a developing solution;
an embedding unit that supplies an embedding liquid to the substrate;
an ultraviolet ray irradiation unit that irradiates the substrate with ultraviolet rays;
A control unit,
The control unit is
a step of developing the substrate, which has an inorganic resist film formed on the undercoat film and has been subjected to an exposure treatment, with a developer to form a pattern of the inorganic resist;
supplying the filling liquid onto the developed substrate to fill spaces between adjacent convex portions in the pattern;
drying the filled embedding liquid to form an embedding film on the substrate;
and reducing a thickness of the filling film by using ultraviolet light.

Reference Signs List 1, 1A, 1B, 1D, 1E Wafer processing apparatus 3, 3D Control unit 30, 30D Development module 52 UV irradiation module F Buried film H Storage medium RP Inorganic resist pattern RP1 Convex portion Rs Inorganic resist pattern Rs1 Convex portion W Wafer

Claims (9)

a step of developing the substrate, which has an inorganic resist film formed on the undercoat film and has been subjected to an exposure treatment, with a developer to form a pattern of the inorganic resist;
supplying a filling liquid to the developed substrate to fill spaces between adjacent convex portions in the pattern;
drying the filled embedding liquid to form an embedding film on the substrate;
and reducing a thickness of the buried film by ultraviolet light. The substrate processing method according to claim 1, wherein the base film and the filling film are the same type of organic film. The substrate processing method according to claim 1 or 2, further comprising a step of irradiating the base film with ultraviolet light in an oxygen-containing atmosphere before the inorganic resist coating is formed on the base film. The substrate processing method according to claim 1 or 2, further comprising a step of supplying water to the base film or exposing the base film to an ozone atmosphere before the inorganic resist coating is formed on the base film. The substrate processing method according to claim 1 or 2, wherein the step of reducing the thickness of the filling film comprises removing the filling film so that the filling film remains at the bottom between the patterns. measuring a state of the pattern after the step of reducing the thickness of the filling film;
3. The substrate processing method according to claim 1, further comprising: a step of making a decision relating to pattern collapse, including a decision of processing conditions relating to the buried film, based on a measurement result in the measuring step. The substrate processing method according to claim 1 or 2, wherein the filling liquid contains, as a subcomponent, a component that improves the solubility of the inorganic resist in the filling liquid. A readable computer storage medium storing a program that operates on a computer of a control unit that controls a substrate processing apparatus so as to cause the substrate processing apparatus to execute a substrate processing method,
The substrate processing method includes:
a step of developing the substrate, which has an inorganic resist film formed on the undercoat film and has been subjected to an exposure treatment, with a developer to form a pattern of the inorganic resist;
supplying a filling liquid to the developed substrate to fill spaces between adjacent patterns, and then drying the filling liquid to form a filling film on the substrate;
and reducing the thickness of the embedding film with ultraviolet light. A substrate processing apparatus for processing a substrate,
a developing section for developing the substrate with a developing solution;
an embedding unit that supplies an embedding liquid to the substrate;
an ultraviolet ray irradiation unit that irradiates the substrate with ultraviolet rays;
A control unit,
The control unit is
a step of developing the substrate, which has an inorganic resist film formed on the undercoat film and has been subjected to an exposure treatment, with a developer to form a pattern of the inorganic resist;
supplying the filling liquid onto the developed substrate to fill spaces between adjacent convex portions in the pattern;
drying the filled embedding liquid to form an embedding film on the substrate;
and reducing a thickness of the filling film by using ultraviolet light.

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