Substrate manufacturing method and sublimation drying method

Abstract

The method for manufacturing the substrate of the present invention includes: a preparation step of preparing a substrate having a surface with an uneven structure; a placement step of placing the substrate, in which at least the recesses of the uneven structure are filled with a cleaning liquid, in a chamber; a supply step of supplying a liquid sublimable substance or a liquid sublimable film forming composition containing a sublimable substance to at least the recesses of the substrate placed in the chamber; and a sublimation drying step of solidifying a film formed by the supplied sublimable substance or sublimable film forming composition and removing it by sublimation; wherein in the sublimation drying step, when the dew point temperature of the gas environment in the chamber at 1 atmosphere is defined as Tdp℃ and the lowest temperature of the film at the surface temperature during the solidification process is defined as Tmin℃, Tdp and Tmin are controlled such that Tmin > Tdp.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a substrate and a method for sublimation drying. Prior Technology

[0002] Sublimation drying is a drying method performed during the cleaning process of micro-semiconductor structures, i.e., patterns. Sublimation drying forms a film of a sublimable substance on the pattern formed on the substrate surface, which is then evaporated and removed. Therefore, it can be used to suppress pattern collapse.

[0003] Patent Document 1 discloses a technique related to the aforementioned sublimation drying method. Patent Document 1 describes a substrate drying method comprising: a sublimable substance filling step, wherein a solution of a sublimable substance is supplied to the substrate to fill the recesses of the aforementioned pattern; a solvent drying step, wherein the solvent in the aforementioned solution is dried, and the aforementioned sublimable substance is filled into the recesses of the aforementioned pattern in a solid state; and a sublimable substance removal step, wherein the substrate is heated to a temperature higher than the sublimation temperature of the aforementioned sublimable substance to remove the aforementioned sublimable substance from the substrate (claim 1 of Patent Document 1).

[0004] Patent Documents Patent Document 1: Japanese Patent Publication No. 2012-243869 Summary of the Invention

[0005] However, the inventors' research has shown that there is room for improvement in the stability of pattern collapse suppression in the sublimation drying method described in the aforementioned Patent Document 1.

[0006] Among the overlapping studies on the aforementioned sublimation drying method, it is evident that even when using the same composition of the component used to form the sublimable film (hereinafter sometimes referred to as "sublimation film forming composition") to sublimate and dry patterned specimens, the reproducibility or tendency of pattern collapse suppression is sometimes difficult to discern. Specifically, when using the sublimation film forming composition to attempt to suppress pattern collapse, results may vary depending on the test case, sometimes yielding almost complete suppression of pattern collapse across the entire specimen, sometimes failing to suppress it, and sometimes resulting in a mixture of areas where collapse can be suppressed and areas where suppression is insufficient, on a scale of micrometers to millimeters.

[0007] Further research revealed that after the sublimation film forming composition is supplied to the wafer, it tends to be affected by the dew point of the gas environment in contact with the surface of the formed coating film. It can be inferred that if the dew point temperature of the aforementioned gas environment is high, the moisture contained in the gas environment on the surface of the coating film will be absorbed by the coating film, either entirely or partially, or condense on the surface of the coating film, either entirely or partially. Furthermore, especially when the sublimation film forming composition contains a solvent, it can be inferred that the heat of vaporization during solvent evaporation will draw heat away from the coating film or the wafer, making condensation more likely. As described above, the moisture absorbed by the coating film or the condensation on the surface of the coating film will conceivably hinder the formation of the sublimation film obtained by solidifying the coating film, leading to poor solidification of the sublimation film. Consequently, it becomes impossible to fully or partially suppress pattern collapse, making reproducibility or trends difficult to observe.

[0008] Based on the insights obtained above, by controlling the dew point temperature (T dp) of the gas environment in the chamber containing the film at 1 atmosphere to be lower than the lowest temperature (T min) of the film at its surface during the solidification process of the film composed of sublimable material or sublimable film, pattern collapse can be stably suppressed in the manufacturing method of substrate using sublimation drying, thus achieving the present invention.

[0009] According to one embodiment of the present invention, the following methods for manufacturing a substrate and for sublimation drying can be provided.

[0010] 1. A method for manufacturing a substrate, comprising: The process includes a preparation step, which prepares a substrate with an uneven surface structure; a placement step, which places the substrate, with at least the recesses of the uneven structure containing a cleaning solution, into a chamber; a supply step, which supplies a liquid sublimable substance or a liquid sublimable film forming composition containing a sublimable substance to at least the recesses of the substrate placed in the chamber; and a sublimation drying step, which causes the film formed by the supplied sublimable substance or the sublimable film forming composition to solidify (including sublimation) and be removed by sublimation; wherein in the sublimation drying step, when the dew point temperature of the gas environment in the chamber at 1 atmosphere is set as Tdp℃ and the lowest temperature of the film on the surface during the solidification process is set as Tmin℃, Tdp and Tmin are controlled such that Tmin>Tdp.

[0011] 2. The substrate manufacturing method as described in 1, wherein in the aforementioned sublimation drying process, T dp and T min are controlled to satisfy T min - T dp ≧ 20.

[0012] 3. The substrate manufacturing method as described in 1. or 2, wherein in the aforementioned sublimation drying process, after the surface temperature of the aforementioned film reaches the aforementioned minimum temperature before the solidification process, the final temperature at which the temperature rise stops is set as T up℃, and T dp and T up are controlled to satisfy T up>T dp.

[0013] 4. A method for manufacturing a substrate as described in any one of 1. to 3., comprising a process selected from one or more of the following: "supplying a dry gas to the interior of the aforementioned chamber or replacing the gas inside the aforementioned chamber with the aforementioned dry gas in a process preceding the aforementioned supply process", "contacting the aforementioned dry gas to the surface of the aforementioned film in the aforementioned sublimation drying process", and "heating the aforementioned substrate in the aforementioned sublimation drying process".

[0014] 5. A method for manufacturing a substrate as described in any one of 1. to 4., wherein the aforementioned sublimation drying process includes a process of "supplying a drying gas to the interior of the aforementioned chamber and discharging the gas from the interior of the aforementioned chamber during the solidification process of at least the aforementioned film".

[0015] 6. The method for manufacturing a substrate as described in 4 or 5, wherein the aforementioned drying gas includes a drying inert gas.

[0016] 7. A method for manufacturing a substrate as described in any one of 1. to 6., wherein the substance supplied in the aforementioned supply process is the aforementioned sublimable film forming composition, wherein the aforementioned sublimable film forming composition comprises the aforementioned sublimable substance and solvent.

[0017] 8. The method for manufacturing a substrate as described in 7, comprising a solvent A1, wherein the solvent A1 has a saturated solubility of the aforementioned sublimable substance exceeding 10% by mass and a boiling point that is more than 5°C lower than the boiling point of the aforementioned sublimable substance at 1 atmosphere.

[0018] 9. The method for manufacturing the substrate as described in 7, which includes: Solvent A2 has a saturated solubility of more than 10% by mass for the aforementioned sublimable substance; and solvent B2 has a content in the sublimable film-forming composition greater than the content of the aforementioned solvent A2, and a boiling point less than the boiling point of the aforementioned sublimable substance at 1 atmosphere and less than the boiling point of the aforementioned solvent A2.

[0019] 10. A method for manufacturing a substrate as described in any one of 1. to 9., wherein the heat of solidification of the aforementioned sublimation substance is 200 J / g or less.

[0020] 11. A method for manufacturing a substrate as described in any one of 1. to 10., wherein the aforementioned cleaning solution contains an alcohol having 3 or fewer carbon atoms.

[0021] 12. A method for manufacturing a substrate as described in any one of 1. to 11., wherein the substrate has the aforementioned uneven structure with a pattern size of 30 nm or less on the aforementioned surface.

[0022] 13. The method for manufacturing a substrate as described in 12, wherein the substrate has the aforementioned uneven structure on the aforementioned surface with a pattern size of 20 nm or less.

[0023] 14. A method for manufacturing a substrate as described in any one of 1. to 13., wherein the aforementioned sublimation film forming composition is free of water or contains water in a content of 10% by mass or less relative to 100% by mass of the aforementioned sublimation substance.

[0024] 15. A sublimation drying method, comprising a sublimation drying step, wherein the sublimation drying step causes a film formed of a sublimable substance or a sublimable film-forming composition containing the sublimable substance to solidify and be removed by sublimation; wherein In the aforementioned sublimation drying process, the dew point temperature of the gas environment surrounding the aforementioned membrane at 1 atmosphere is defined as T dp℃, and the lowest temperature of the aforementioned membrane at the surface temperature before the solidification process is defined as T min℃, and T dp and T min are controlled to satisfy T min>T dp.

[0025] According to the present invention, a method for manufacturing a substrate with excellent stability in suppressing pattern collapse during sublimation drying and a sublimation drying method are provided. Simple Explanation of the Diagram

[0026] Figure 1 is a schematic cross-sectional view illustrating one example of the manufacturing process of the substrate in this embodiment.

[0027] Figure 2 is a cross-sectional view illustrating one example of a substrate processing apparatus. Implementation

[0028] The following uses drawings to illustrate various embodiments of the present invention. Furthermore, in all drawings, the same symbols are used to denote the same constituent elements, and descriptions are omitted where appropriate. Also, the figures are schematic diagrams and do not reflect the actual dimensions.

[0029] The manufacturing method of the substrate of this embodiment is described in summary.

[0030] The method for manufacturing a substrate according to this embodiment includes: a preparation step, preparing a substrate with a surface having an uneven structure; a placement step, placing a substrate having a cleaning liquid loaded in at least the recesses of the uneven structure in a chamber; a supply step, supplying a liquid sublimable substance or a liquid sublimable film forming composition containing a sublimable substance to at least the recesses of the substrate placed in the chamber; and a sublimation drying step, causing the film formed by the supplied sublimable substance or sublimable film forming composition to solidify and be removed by sublimation; wherein in the above-mentioned sublimation drying step, when the dew point temperature of the gas environment in the chamber at 1 atmosphere is set as T dp℃, and the lowest temperature of the film at the surface temperature during the solidification process is set as T min℃, T dp and T min are controlled to satisfy T min>T dp.

[0031] According to the inventors' understanding, in the method for manufacturing a substrate using the sublimation drying method, by means of the above-mentioned solidification process, the dew point temperature (T dp) of the gas environment in the chamber where a film made of a sublimable substance or a sublimable film forming composition is disposed is controlled at 1 atmosphere to be lower than the lowest temperature (T min) of the film at the surface, thereby stably suppressing the collapse of the pattern.

[0032] The detailed mechanism is still undetermined, but it can be speculated that by controlling the minimum temperature on the membrane surface to be higher than the dew point temperature in the chamber, water absorption or condensation on the membrane surface can be suppressed, thus suppressing poor coagulation in the sublimation membrane. As a result, the pattern collapse suppression capability caused by the sublimation membrane can be stably exerted.

[0033] Furthermore, if the gaseous environment in contact with a membrane composed of sublimable substances or sublimable film has a high water content (humidity), it is conceivable that water will be absorbed or condensation will occur on the membrane surface, resulting in poor condensation. However, poor condensation itself is difficult to observe.

[0034] In response, by setting the surface temperature of the membrane and the dew point temperature of the gas environment in which the membrane is in contact as indicators, it becomes possible to evaluate the tendency of pattern collapse rate with good reproducibility.

[0035] This calculation of the collapse rate is an indicator for evaluating the collapse condition of convex-concave patterns. For example, if the pattern is a convex cylindrical shape that is easily identifiable for collapse in an overhead image, a scanning electron microscope (SEM) can be used to observe the patterned specimen. The collapse of the convex parts in the convex-concave structure (pattern collapse) can be calculated, and the proportion of convex shapes relative to the number of observed areas (collapse rate) can be determined. If a collapse rate of less than 30% is obtained from SEM image observation with a probability of more than 50%, pattern collapse can be considered stably suppressed. Furthermore, obtaining a collapse rate of less than 30% with a probability of more than 70% is preferable, and obtaining it with a probability of more than 80% is even better.

[0036] In this instruction manual, each SEM image is measured at observation points at least 1 mm apart. Furthermore, the SEM magnification is adjusted in each SEM image to allow observation of 500-600 patterns.

[0037] The following details each step of the substrate manufacturing method of this embodiment.

[0038] One example of the substrate manufacturing method of this embodiment includes a preparation process, an arrangement process, a supply process, and a sublimation drying process. The substrate manufacturing method will be illustrated using Figures 1(a) to (c) as an example of semiconductor wafer manufacturing.

[0039] As an overview of the semiconductor wafer manufacturing process, fine embossed patterns are formed on the surface of a substrate (wafer) through processes such as film deposition, photolithography, or etching. Afterward, in order to clean the wafer surface, a wet process, such as a cleaning process using water or organic solvents, is performed. In order to remove the cleaning solution or rinsing solution that adheres to the wafer due to the wet process, a drying process is generally also performed.

[0040] In this drying process, it is known that in semiconductor substrates with fine embossed patterns, deformation or collapse of the embossed patterns can easily occur.

[0041] In order to dry the substrate with raised and recessed patterns formed by using a sublimation substance, a process is generally performed to replace residual liquids such as cleaning solution remaining in the raised and recessed patterns with a treatment liquid containing the sublimation substance.

[0042] In the substrate manufacturing method of this embodiment, a substrate 10 with a surface having a concave-convex structure 20 is first prepared (preparation process).

[0043] Alternatively, the following method, which is an example of a method for forming a rough and uneven structure 20 on the surface of the substrate 10, may be used.

[0044] For example, after coating a photoresist onto the wafer surface, an intermediate photoresist mask is used to expose the photoresist. By removing the exposed or unexposed photoresist, a photoresist with a desired raised or recessed pattern is created. Alternatively, a patterned mold can be pressed onto the photoresist to obtain a photoresist with a raised or recessed pattern. Next, the wafer is etched. At this time, the substrate surface corresponding to the recessed portions of the photoresist pattern can be selectively etched. Finally, the photoresist is peeled off to obtain a wafer (substrate 10) with a raised or recessed structure 20 on its surface.

[0045] The wafer with the uneven structure 20 and the material of the uneven structure 20 are not particularly limited. As a wafer, various wafers can be used, such as silicon wafers, silicon carbide wafers, wafers composed of multiple components containing silicon elements, sapphire wafers, various compound semiconductor wafers, plastic wafers, etc. Furthermore, the material of the uneven structure 20 can also be: silicon-based materials such as silicon oxide, silicon nitride, polycrystalline silicon, and monocrystalline silicon; metallic materials such as titanium nitride, tungsten, ruthenium, tantalum nitride, and tin; materials combining these; photoresist materials, etc.

[0046] Figure 1(a) is a cross-sectional view illustrating an example of the uneven structure 20. The pattern size in the cross-sectional structure (in the substrate thickness direction) of the uneven structure 20, which includes at least one of its width and height, or in the three-dimensional structure (XYZ coordinates) of the uneven structure 20, which includes at least one of its width (length in the X-axis direction), height (length in the Y-axis direction), and depth (length in the Z-axis direction), can, for example, be less than 30 nm, less than 20 nm, or less than 10 nm. Even when using a substrate 10 with such a fine uneven structure 20, the pattern collapse rate can be reduced by using the sublimation drying method of this embodiment.

[0047] Furthermore, in the cross-sectional view of Figure 1, the inclination of the uneven structure 20 is parallel (not intersecting) with the substrate thickness direction. However, the drying component of this embodiment can still be used even if the inclination of the uneven structure 20 is not parallel with the substrate thickness direction. The aforementioned "not parallel" means, for example, in the cross-sectional structure of Figure 1, the inclination of the uneven structure 20 is orthogonal to the substrate thickness direction, or the inclination of the uneven structure 20 intersects the substrate thickness direction (excluding orthogonality).

[0048] The lower limit of the aspect ratio of the protrusion 22 can also be, for example, 3 or more, 5 or more, or 10 or more. Pattern collapse can be suppressed even in the concave-convex structure 20 with a protrusion 22 having a fragile structure.

[0049] On the other hand, the upper limit of the aspect ratio of the protrusion 22 is not particularly limited, but it can be below 100.

[0050] The aspect ratio of the protrusion 22 is represented by dividing the height of the protrusion 22 by the width of the protrusion 22.

[0051] Next, the substrate 10, in which at least one of the recesses 24 of the concave-convex structure 20 is filled with cleaning fluid, is placed in the cavity (placement process).

[0052] As an example of the configuration process, a method can be used to place the substrate 10 in the chamber 1 of the processing apparatus 100 of FIG2 and supply cleaning fluid to the recess 24 of the substrate 10 in the chamber 1.

[0053] Figure 2 is a cross-sectional schematic diagram illustrating the structure of the processing device 100 on the surface of the processing substrate 10.

[0054] The processing device 100 in Figure 2 includes a chamber 1, a rotating mechanism 3, a stage 2, a nozzle 4, a nozzle 5, a gas inlet 6, and a gas outlet 7.

[0055] Inside chamber 1, substrate 10 is mounted on stage 2 in a detachable manner. Stage 2 is equipped with substrate support mechanisms such as holding pins or spin chucks (not shown). Stage 2 can rotate about its thickness direction via a rotation mechanism 3.

[0056] For the surface of the substrate 10 disposed on the stage 2, for example, cleaning fluid can be supplied via nozzle 4, and a liquid sublimable substance or a liquid sublimable film forming composition can be supplied via nozzle 5. The arrangement and orientation of nozzles 4 and 5 are not particularly limited as long as they can efficiently supply liquid to the surface of the substrate 10. Furthermore, since the sublimable substance is in a solid state, it will solidify into a condensed solid if cooled while remaining at the nozzle tip. If this condensed solid is not intended to mix into the surface of the substrate 10, there is concern that it may affect the stability of pattern collapse suppression. In this regard, the temperature of the nozzle or nozzle tip can be adjusted, or a shielding member can be attached to prevent residual liquid sublimable substance or the aforementioned condensed solid from mixing into the surface of the substrate 10.

[0057] Dry gas or other gases can be supplied to the chamber 1 through the gas inlet 6, and residual gas or supplied gas in the chamber 1 can be discharged through the gas outlet 7. Each gas inlet 6 and gas outlet 7 can also be equipped with a variable gas volume mechanism. Furthermore, there can be one or more gas supply ports that directly supply gas to the surface of the substrate 10. The gas supply port can be one that ejects gas by colliding with the surface of the substrate 10, or one that ejects gas along the surface of the substrate 10. Moreover, the aforementioned gas inlet 6 can also serve as a gas supply port.

[0058] Furthermore, a temperature adjustment device that can heat up or cool down the gas environment or substrate 10 in the chamber 1 can be installed as needed, and sensors such as surface thermometers or dew point thermometers can also be installed.

[0059] Water or organic solvents can be used as cleaning solutions, but it is generally preferred to use at least one alcohol selected from methanol, 1-propanol, and 2-propanol, which have 3 or fewer carbon atoms. This makes it relatively easy to replace the cleaning solution remaining on the uneven structure 20 of the substrate 10 with a liquid sublimable substance or a liquid sublimable film formation composition.

[0060] Next, after the configuration process, as shown in FIG1(a), a liquid sublimation substance or a liquid sublimation film forming composition 30 is supplied to at least the recess 24 of the substrate 10 in the chamber 1 (supply process).

[0061] The sublimable substance and sublimable film-forming composition 30 used in the supply process are preferably liquid at an environment of 20-30°C, and more preferably a solution. Alternatively, it can be supplied by filling part or all of the recesses 24 of the uneven structure 20 (sometimes described as "a process for supplying the sublimable film-forming composition" or simply as "a filling process" or "a supply process"). The supply can also be carried out at, for example, an environment of 20-30°C.

[0062] The method for supplying the sublimable material and the sublimable film forming composition 30 can use well-known means, but can also use, for example, a single-wafer type represented by "while holding the wafers one by one at almost horizontal and rotating them as shown in FIG2, supplying the composition near the center of rotation to replace the cleaning fluid loaded on the uneven pattern of the substrate, etc., and filling the composition", or a batch type such as "immersing multiple wafers in a composition tank to replace the cleaning fluid loaded on the uneven pattern of the wafers, etc., and filling the composition".

[0063] Furthermore, the sublimable substances used can be purified beforehand. Purification of sublimable substances can be achieved using separation methods such as sublimation purification, filtration purification, or distillation.

[0064] Next, after the supply process, as shown in Figure 1(b), in chamber 1, the film 50 formed by the supplied sublimable substance or sublimable film forming composition is solidified, as shown in Figure 1(c), and the sublimable film formed by the solidification of film 50 is removed by sublimation (sublimation drying process).

[0065] The term "film 50" as formed from a sublimable substance or a sublimable film-forming composition refers to both a coated film and a sublimable film. At this time, film 50 may have the same composition as the aforementioned sublimable substance or the aforementioned sublimable film-forming composition 30 immediately following its supply, or it may have a different composition ratio from the original composition due to the volatilization of components from the aforementioned sublimable substance or the aforementioned sublimable film-forming composition 30.

[0066] In this specification, the term "sublimable film" refers to a sublimable substance formed as a film on the substrate 10. This sublimable film need not have the fluidity of a liquid, and may contain unvolatile solvents, etc.

[0067] Furthermore, in order to form a sublimation film, a sublimation substance in liquid state or a sublimation film forming composition 30 in liquid state is supplied to the substrate 10 and spread into a film. At this time, the material of the sublimation film has fluidity, so a liquid film (liquid film) is formed on the substrate 10. In this specification, this liquid film is defined as a "coated film".

[0068] The sublimable substance in the liquid state or the sublimable film forming composition 30 is solidified, and a film 50 containing the solidified sublimable substance is formed on the uneven structure 20 (hereinafter sometimes referred to as "the process of forming a sublimable film" or simply "the solidification process" for illustrative purposes). In this way, the pattern collapse of the uneven structure 20 can be suppressed by the film 50 filling the recesses 24 of the uneven structure 20.

[0069] To more stably suppress pattern collapse, the formed film 50 is preferably configured such that its surface covers at least the protrusions 22 of the uneven structure 20. Furthermore, the film 50 may exist within the recesses 24 to a degree sufficient to suppress pattern collapse, or it may not be necessary to completely fill the recesses 24.

[0070] As a means of solidification, the sublimable substance of the solid can also be precipitated by cooling. In particular, in the case of the sublimable film forming composition 30, the solvent can also be evaporated by heating or applying appropriate environmental conditions, and the sublimable substance of the solid can be precipitated through its heat of vaporization.

[0071] In this embodiment, the sublimable film-forming composition 30 preferably contains a sublimable substance and a solvent. By appropriately selecting the type of solvent contained in the sublimable film-forming composition 30, it becomes possible to carry out solvent evaporation (drying) at, for example, ambient temperature and pressure (20°C~25°C, 1 atm).

[0072] Furthermore, the lower limit of the freezing point of the sublimable substance is, for example, above 5°C at 1 atmosphere, preferably above 20°C, and even more preferably above 50°C. By setting the lower limit of the freezing point of the sublimable substance to be above the aforementioned lower limit value, the sublimable substance can be solidified by the heat of vaporization of the solvent without extreme cooling, and it is also not necessary to keep the dew point temperature in chamber 1 at an extremely low level.

[0073] In addition, when the film 50 is solidified at room temperature and pressure, methods such as rotating the substrate 10 or blowing inert gas onto the substrate 10 can be used as needed to promote the evaporation of the solvent.

[0074] During the solidification process, the dew point temperature of the gas environment within the chamber 1 containing the membrane 50 at 1 atmosphere is defined as Tdp℃, and the lowest surface temperature of the membrane 50 is defined as Tmin℃. Tdp and Tmin are controlled such that Tmin > Tdp. Furthermore, it is generally conceivable that solidification will occur at the surface of the membrane 50; therefore, it is preferable that Tmin > Tdp is satisfied at least at the surface of the membrane 50. More preferably, it is also acceptable that Tmin > Tdp is satisfied when the solidification of the membrane 50 is complete and a sublimation membrane is obtained.

[0075] Furthermore, the so-called "solidification process" can also be defined as the period during which the solidification phenomenon of the membrane 50 occurs (or proceeds). Alternatively, as will be described later, it can be defined as the period from the point when the surface temperature of the membrane 50 begins to decrease until the point when the rise in the surface temperature of the membrane 50 becomes invisible.

[0076] In this specification, the term "gas environment" in relation to the gas environment in contact with membrane 50 (coated membrane and sublimation membrane) generally refers to air or gas in contact with the surface of membrane 50 during the solidification process. However, it can also be defined as fluid present at a distance of 10 mm from the surface of membrane 50 when the surface of membrane 50 is taken as the reference.

[0077] The dew point temperature Tdp is the dew point temperature of the gaseous environment described above at 1 atmosphere (atmospheric pressure), and can be measured using a dew point meter. A dew point meter can be used to evaluate Tdp to be an appropriate value, and known methods can be used; examples include mirror-cooled dew point meters and capacitive dew point meters. Furthermore, methods for converting relative humidity or absolute humidity into dew point temperature can also be used. Known methods can be used to measure relative humidity or absolute humidity; examples include electric hygrometers.

[0078] Furthermore, when a fluid with the desired dew point temperature is supplied to the chamber 1 and comes into contact with the surface of the membrane 50 (coated membrane and sublimation membrane), if the change in dew point temperature between the supply from the fluid supply port and the contact is so small as to be negligible, the dew point temperature of the fluid during supply can be regarded as the dew point temperature T dp of the gas environment in the chamber 1.

[0079] Known gas drying methods can be used to lower the dew point temperature, but specific examples include processes such as "supplying drying gas to the interior of chamber 1 or replacing the gas inside chamber 1 with drying gas in a process preceding the supply process," "bringing the drying gas to the surface of membrane 50 during the solidification process," and "heating the substrate 10 during the solidification process." The solidification process of the membrane in the sublimation drying process may also include one or more processes selected from the group consisting of these processes. In this method, it is preferable that the drying gas is supplied not only to the periphery of membrane 50 but also to the entire chamber in which membrane 50 is disposed, and it is preferable that it fills the entire chamber. In this way, it becomes possible to stably maintain the environmental conditions around membrane 50 during the solidification process.

[0080] Lowering the dew point temperature is preferable if it is done after the preparation process and before the supply process, as this can inhibit the absorption of moisture by sublimable substances or sublimation film-forming components in the supplied liquid state.

[0081] Furthermore, the dew point temperature during the solidification process only needs to satisfy T min > T dp, and the adjustment end time is not limited, but it can also be set until solidification is completed and a sublimation film is formed. Specifically, the sublimation drying process can also include the treatment of "supplying dry gas to the inside of chamber 1 and discharging the gas inside chamber 1 during the solidification process of at least the film 50".

[0082] Furthermore, the dew point temperature can be further lowered while removing the sublimation film.

[0083] Dry gas can be supplied to chamber 1 of the processing device 100 in Figure 2 through gas inlet 6, and can be discharged to the outside through gas outlet 7.

[0084] For example, a treatment can be applied to "blow or blow dry gas toward the surface of the substrate 10 in a manner that allows the gas to come into contact with it, or to circulate or blow dry gas parallel to the surface," and the dry gas can be filled into the chamber. Furthermore, when supplying dry gas, exhaust can also be performed simultaneously, and the dry gas can be continuously supplied at a constant rate. When using a sublimable film-forming composition, since the volatile solvent is released into the chamber 1, it is preferable to simultaneously supply dry gas and exhaust gas from the chamber 1, so that a new supply of dry gas is constantly supplied to the chamber 1 until at least the film 50 has solidified.

[0085] Any gas used for drying can be used as long as it does not hinder sublimation and drying. Examples include drying air or drying inert gases, with drying inert gases being preferred, but not limited to these. Specific examples of inert gases for drying include rare gases such as nitrogen or argon.

[0086] The surface temperature of the film 50, from the coated film to the sublimated film, can be measured using a non-contact radiation thermometer or the like. In this specification, the film cured by the coated film is a sublimated film, therefore the temperature of the coated film and the temperature of the sublimated film are not particularly distinguished.

[0087] In the film 50 formed from the sublimable film forming composition 30 containing a sublimable substance and a solvent, cooling first occurs due to the volatilization (heat of vaporization) of the solvent, followed by a phenomenon where heat moves from the surroundings to near the ambient temperature. Therefore, the surface temperature of the film 50 decreases after the aforementioned sublimable substance or the aforementioned sublimable film forming composition 30 is supplied to the substrate 10. After reaching a minimum temperature T min, it rises to approximately the temperature of the gas environment within the chamber 1 without heating the substrate 10, at which point the temperature rise stops. The surface temperature of the film 50 at which this temperature rise stops is defined as T up.

[0088] Furthermore, the rate at which the surface temperature decreases or increases is not particularly limited; it can proceed slowly and at an indefinite rate.

[0089] During solidification, Tdp and Tmin are ideally controlled to satisfy, for example, Tmin - Tdp ≥ 10, preferably Tmin - Tdp ≥ 20, and even better, Tmin - Tdp ≥ 30. This also reduces the deviation in collapse inhibition caused by the type of sublimable substance.

[0090] During solidification, Tdp and Tup can be controlled to satisfy, for example, Tup > Tdp, preferably Tup - Tdp ≥ 20, and even better, Tup - Tdp ≥ 30. This can further improve the stability of pattern collapse suppression during sublimation drying.

[0091] Furthermore, in addition to lowering the dew point temperature Tdp of the gas environment within chamber 1, the dew point temperature Tdp can also be relatively lowered by increasing the temperature of the coating film and the sublimation film. Methods for increasing the surface temperature of film 50 include: preheating the sublimation material and sublimation film forming composition supplied to substrate 10 before using them in the coating film forming process; preheating the substrate 10 to be dried; or heating the substrate 10 to be dried and / or the aforementioned composition during the coating film and / or sublimation film forming process.

[0092] Next, as shown in Figure 1(c), the sublimable film formed by the solidification of the film 50 is removed by sublimation. That is, the film 50 on the uneven structure 20 is removed by sublimation of the solid sublimable substance (sometimes described as "process of removing sublimable film" or simply "removal process" for illustrative purposes).

[0093] The method for sublimating a substance can be appropriately selected according to its boiling point. For example, if the boiling point is low, it can be sublimated at room temperature and pressure, but if necessary, heating or pressure reduction can also be performed.

[0094] Furthermore, in this embodiment, the aforementioned coagulation process and removal process are described separately for illustrative purposes, but there is no need for a clear distinction. It is also possible that the process from the coagulation of the membrane to the removal of the sublimated membrane occurs continuously, or that the more difficult the separation, the shorter the time it will take.

[0095] The manufacturing method shown in Figure 1 is for wafer patterns, but the present invention is not limited thereto. The substrate manufacturing method of this embodiment can also be used for photoresist patterns, and the collapse of the photoresist pattern can be suppressed by using the sublimation film forming composition of the present invention in the cleaning and drying process.

[0096] Regarding the aforementioned supply process, a manufacturing method has been described that is performed after the cleaning process, but it is not limited to this. It can also be performed after various treatments applied to the uneven structure 20. For example, the supply process can also be performed after the solution for forming a water-repellent protective film has been applied to the uneven structure 20.

[0097] The substrate manufacturing method may also combine one or more well-known treatments in addition to the above-mentioned steps. For example, surface treatments such as plasma treatment may be performed after the above-mentioned removal steps.

[0098] Furthermore, the sublimation drying method of this embodiment can be applied to various other uses besides the aforementioned substrate manufacturing method.

[0099] The sublimation drying method includes a sublimation drying step of "solidifying a film composed of a sublimable substance or a sublimable film containing a sublimable substance and removing it by sublimation". As mentioned above, in the sublimation drying step, when the dew point temperature of the gas environment surrounding the film at 1 atmosphere is defined as T dp℃ and the lowest temperature of the film at the surface temperature during the solidification process is defined as T min℃, T dp and T min are controlled to satisfy T min>T dp.

[0100] The following details the sublimation substances and sublimation film-forming components of this embodiment.

[0101] (Sublimation film-forming components)

[0102] Sublimation film-forming components contain one or more sublimation substances.

[0103] Sublimable materials can be those that disappear entirely upon a specified heat treatment, or those that disappear after standing at 23°C under 1 atmosphere of pressure. In the substrate manufacturing process, the sublimable film is not a permanent film that remains on the substrate, but is used as a sacrificial film that will be removed in subsequent processes. Therefore, the sublimable film forming composition can be used as a composition for forming a sublimable sacrificial film.

[0104] The lower limit of the content of sublimable substances in sublimable film-forming compositions is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, and more preferably 0.8% by mass or more. This makes it easier for the sublimable substances to solidify uniformly in the sublimable film-forming composition.

[0105] On the other hand, the upper limit of the content of sublimable substances in the sublimable film-forming composition is, for example, 80% by mass or less, preferably 50% by mass or less, and more preferably 40% by mass or less. This makes it easier to obtain the cooling effect caused by the heat of vaporization of the solvent, thus promoting the solidification of the sublimable substances. Furthermore, it shortens the time required for sublimation (sublimation time), which is also preferable.

[0106] Furthermore, the sublimable film-forming composition 30 is preferably anhydrous or contains water at a content of 10% by mass or less relative to 100% by mass of the sublimable substance. This improves the pattern collapse suppression capability of the sublimable film-forming composition 30.

[0107] In the case where the sublimable substance has polar sites, if the mass ratio of the sublimable substance is less than 10 / 100, then even if the sublimable film-forming composition contains water, the collapse of the pattern can be stably suppressed. Furthermore, examples of the aforementioned polar sites include -OH, -O-, -(C=O)-, -NH₂, -(NH)-, and tertiary amino groups.

[0108] Furthermore, when the sublimant is nonpolar or when water is not a good solvent for the sublimant, it is desirable for the sublimant film-forming composition to be as free of water as possible. The specific mechanism is unclear, but it can be speculated that if the sublimant is nonpolar, it will separate from the water, resulting in an inability to stably suppress pattern collapse. While it is desirable for the sublimant film-forming composition to be as free of water as possible, it can also be defined as, for example, less than 0.01 parts per 100 of the mass of the sublimant.

[0109] The first sublimable film-forming composition (hereinafter referred to as "the sublimable film-forming composition of the first embodiment") may also include a solvent A1 having moderate solubility for sublimable substances and moderate volatility, and the second sublimable film-forming composition (hereinafter referred to as "the sublimable film-forming composition of the second embodiment") may also include a solvent A2 having moderate solubility for sublimable films and a solvent B2 having moderate volatility.

[0110] The detailed mechanism is still undetermined, but it is conceivable that the film-forming ability is improved by using highly volatile solvents (solvent A1, solvent B2) that are more volatile than sublimable substances. At the same time, by using highly soluble solvents (solvent A1, solvent A2) with higher solubility for sublimable substances, the precipitation of excessive sublimable substances in the early stage can be suppressed, thus preventing the sublimable substances in the early stage from becoming the starting point for pattern collapse.

[0111] (Sublimable substances)

[0112] In this specification, "sublimable substance" refers to a substance that has a vapor pressure in the solid state.

[0113] Sublimable substances can be used in principle as long as they are solid at a specific temperature and have vapor pressure.

[0114] The lower limit of the freezing point of a sublimable substance, as described above, is, for example, above 5°C at 1 atmosphere, preferably above 20°C, and even more preferably above 50°C. Therefore, in substrate manufacturing methods, it is unnecessary to implement extremely low-temperature processes for the solidification of the sublimable substance, thus improving the manufacturing stability of the semiconductor substrate.

[0115] On the other hand, the upper limit of the freezing point of sublimable materials is, for example, below 220°C at 1 atmosphere, preferably below 200°C, and even more preferably below 180°C. Therefore, in substrate manufacturing methods, it is not necessary to perform extreme high-temperature processing for the sublimation of sublimable materials, thus improving the manufacturing stability of semiconductor substrates.

[0116] The lower limit of the heat of solidification of sublimable substances is not particularly limited, but it can be, for example, above 1 J / g, preferably above 5 J / g, and even more preferably above 10 J / g.

[0117] On the other hand, the upper limit of the heat of solidification of the sublimation material is, for example, 200 J / g or less, preferably 100 J / g or less, and even more preferably 50 J / g or less. This helps to suppress the occurrence of strip collapse. Furthermore, in this specification, strip collapse refers to the state where the pattern continuously collapses in a specified direction. And, when it forms in a way that surrounds a region without pattern collapse, it is also defined as strip collapse.

[0118] Sublimable substances can also be composed in a manner that substantially does not contain non-volatile substances that would become residues after sublimation. Non-volatile substances can be removed from the sublimable substance by separation methods such as sublimation purification or distillation. "Substantially not containing" means that it is 1% or less by mass in 100% of the sublimable substance—preferably 0.5% or less by mass—or, where unavoidable contamination is permissible.

[0119] The lower limit of the boiling point of the sublimable substance is, for example, above 60°C at 1 atmosphere, preferably above 100°C, and even more preferably above 110°C. This allows for the stable fabrication of sublimable films containing the sublimable substance.

[0120] On the other hand, the upper limit of the boiling point of sublimable substances, for example, is below 300°C at 1 atmosphere, preferably below 280°C, and even more preferably below 250°C. This makes the purification of sublimable substances easier. Furthermore, sublimation of sublimable substances is easier during processes at room temperature and pressure, which can improve manufacturing efficiency.

[0121] The boiling point or sublimation point of a substance containing multiple sublimable substances is selected from the boiling point or sublimation point of the component with the highest content (mass %) among the components contained in the sublimable substance (however, if there are more than two components with the highest content, the boiling point or sublimation point of the component with the highest temperature is selected).

[0122] The boiling point of sublimable substances is defined as the initial boiling point as defined in JIS K 2254:2018 (ISO 3405).

[0123] Furthermore, when the sublimation point is conventionally used depending on the substance, the sublimation point is used.

[0124] Furthermore, the freezing point of sublimable substances is determined using DSC at a rate of -10°C / min. For sublimable substances containing multiple components, the freezing point of the component with the highest content (mass %) is used (however, if there are two or more components with the highest content, the freezing point of the component with the higher content is used).

[0125] The temperature range at which the sublimable substance is a solid and has a vapor pressure (hereinafter also referred to as the "sublimation temperature range") can be, for example, above 10°C. Therefore, even when used in an environment with a normal room temperature of 20 to 25°C, the sublimable substance can be solidified by cooling caused by the heat of vaporization of the solvent in the composition of the sublimable film.

[0126] Furthermore, if the sublimation temperature range is within 20~25°C, then there is no need for sublimation promotion treatment such as heating or depressurization. The sublimable material can be sublimated more easily under the conditions of the current substrate manufacturing process to remove the sublimable film.

[0127] Furthermore, the vapor pressure when defining the sublimation temperature zone is, for example, 10 Pa or more, preferably 50 Pa or more.

[0128] In this specification, unless otherwise specified, "~" indicates that both the upper and lower limits are included.

[0129] As a sublimation substance, it is not limited as long as it can be used in substrate materials such as semiconductors. Examples include: non-halogen sublimation substance S1 with a low heat of solidification, non-halogen sublimation substance S2 with a high heat of solidification, sublimation substance S3 with a small difference between its freezing point and boiling point, and halogen-containing sublimation substance S4 containing halogen elements. These can be used alone or in combination of two or more.

[0130] The heat of solidification of the non-halogenated sublimable substance S1 is preferably below 50 J / g, and even better below 40 J / g. Because S1 tends to have a large difference between its freezing point and boiling point, it can be purified by distillation in liquid form. Using S1 can suppress the occurrence of strip collapse.

[0131] The heat of solidification of non-halogenated sublimable substances S2 should preferably exceed 50 J / g.

[0132] The difference between the freezing point and boiling point of the sublimable substance S3 is, for example, below 50°C, preferably below 40°C, and even more preferably below 30°C.

[0133] The halogenated sublimable substance S4 can also be a fluorinated sublimable substance containing fluorine as the halogen element.

[0134] From the perspective of suppressing pattern collapse, it is preferable to use sublimation substances of S1 to S3.

[0135] Examples of sublimable substances include: norethene, norethane, camphor, pyridine, 2,3-dichloropyridine, 2,6-dichloropyridine, tetrahydrodicyclopentadiene, dimethyl oxalate, isothiols, neopentyl alcohol, neopentyl glycol, and ethyl carbonate. Among these, neopentyl alcohol, camphor, pyridine, tetrahydrodicyclopentadiene, dimethyl oxalate, isothiols, and ethyl carbonate may also be used. These can be used alone or in combination of two or more. Furthermore, in the presence of optical isomers, one or both may be used.

[0136] (solvent)

[0137] The sublimation film forming composition of this embodiment includes solvent A, in which the saturated solubility of one or more sublimation substances exceeds 10% by mass. Solvent A is defined as including solvent A1 and solvent A2 as described above.

[0138] By using solvent A, which has the dissolving power of sublimable substances, the solidification of sublimable substances at the nozzle tip can be suppressed when the sublimable film forming composition is supplied to the substrate through the intermediate nozzle.

[0139] Saturated solubility can be determined from the saturated concentration (mass %) of the sublimable substance dissolved in the solvent.

[0140] In cases involving multiple solvents, the saturated solubility is determined using the value specified for each solvent.

[0141] When the composition of the sublimable film contains multiple sublimable substances, the saturation solubility is determined by the saturation concentration of the sublimable substance with the highest content (mass %) in the composition (however, if there are two or more sublimable substances with the highest content, the value of the highest saturation concentration shall be used).

[0142] The lower limit of the saturated solubility of the sublimable substance in solvent A is, for example, greater than 10% by mass, preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, and even more preferably 60% by mass or more. This can reduce the proportion of pattern collapse.

[0143] On the other hand, the upper limit of the saturated solubility of the sublimable substance in solvent A can be, for example, 99% by mass or less, or 95% by mass or less.

[0144] Furthermore, the sublimable film-forming composition can also use solvent A, which is miscible with residual liquid remaining on the substrate surface. This allows for efficient replacement of the residual liquid with the sublimable film-forming composition during the aforementioned supply process, enabling stable drying of the residual liquid.

[0145] As residual liquids, as mentioned above, common solvents used in semiconductor cleaning processes can be listed, such as water, alcohols with 3 or fewer carbon atoms (e.g., methanol, 1-propanol, 2-propanol, etc.) or mixtures thereof.

[0146] The term "miscible" means that at 25°C and 1 atmosphere, for 1 part by mass of solvent A, the amount of solvent used in the cleaning process that can be dissolved is, for example, 0.05 parts by mass or more.

[0147] A sublimable film forming composition comprising one or more solvents A1, wherein the saturated solubility of the sublimable substance in solvent A1 exceeds 10% by mass and the boiling point is more than 5°C lower than the boiling point of the sublimable substance at 1 atmosphere, is referred to below as the first embodiment of the sublimable film forming composition.

[0148] In this embodiment, solvent A1 is selected from solvent A that has a boiling point that is more than 5°C lower than the boiling point of the sublimable substance at 1 atmosphere (1).

[0149] In condition (1), (the boiling point of the sublimable substance at 1 atmosphere - the boiling point of solvent A1) can be above 5°C, preferably above 50°C, and more preferably above 80°C. Alternatively, it can be below 200°C, preferably below 180°C.

[0150] In this specification, in the case of an azeotropic solvent, the azeotropic point is used as the boiling point of each solvent in the case of a mixture containing multiple solvents. In the case of a non-azeotropic solvent, the boiling point specified for each solvent is used.

[0151] It is conceivable that in the sublimable film forming composition of the first embodiment, by including at least one of these solvents A1, the highly dissolving solvent A1 will inhibit excessive initial precipitation of the sublimable substance, and the solvent A1, which is more volatile than the sublimable substance, can promote the formation of the sublimable film (solidification of the sublimable substance) through the heat of vaporization. Therefore, after the sublimable film is formed and removed, in addition to reducing the pattern collapse rate, stripe collapse can also be suppressed.

[0152] The sublimation film-forming composition of this embodiment may, in addition to solvent A, include one or more solvents B with boiling points lower than the boiling point of the sublimation substance at 1 atmosphere. Solvent B is defined as including solvent B1 and solvent B2 as described above.

[0153] The sublimation film-forming composition of the first embodiment may also include one or more of the above-mentioned solvents A1 and one or more solvents B1 with boiling points lower than those of solvents A1.

[0154] As long as solvent B1 has a lower boiling point than solvent A1, the saturated solubility of its sublimable substance is not particularly limited, and it can be used even if its saturated solubility is lower than that of solvent A1. The difference between the boiling point of solvent A1 and the boiling point of solvent B1 is, for example, 5°C or more, preferably 10°C or more, and more preferably 15°C or more. On the other hand, it can be below 200°C or below 150°C.

[0155] The boiling point of solvent B1 is, for example, 15℃~85℃, preferably 20℃~80℃, and even more preferably 25℃~70℃.

[0156] The lower limit of the content of solvent A1 in the sublimable film-forming composition is, for example, 0.5% by mass or more, preferably 0.8% by mass or more, and more preferably 0.9% by mass or more.

[0157] Furthermore, in the sublimable film-forming composition, when solvent A1 is the main component of the solvent, the content of solvent A1 in the sublimable film-forming composition can be 50% by mass or more, preferably 80% by mass or more, and even more preferably 90% by mass or more. In this case, if other solvents are used, it is preferable to use solvent B1 as the solvent. In this case, the content of solvent A1 in the sublimable film-forming composition can be made greater than that of solvent B1.

[0158] On the other hand, the upper limit of the content of solvent A1, when the solvent of the sublimable film-forming composition substantially contains only solvent A1 and / or when solvent A1 is defined as the main component of the solvent of the sublimable film-forming composition, can be, for example, 99.9% by mass or less, preferably 99.5% by mass or less, and more preferably 99.2% by mass or less. Furthermore, when the sublimable film-forming composition contains both solvent A1 and solvent B1 and A1 is not defined as the main component of the solvent, the content of solvent A1 in the sublimable film-forming composition, for example, can be made to be less than 50% by mass, preferably 30% by mass or less, and more preferably 15% by mass or less.

[0159] A sublimation film forming composition comprising one or more solvents A2 and one or more solvents B2, wherein the saturated solubility of the sublimable substance in solvent A2 exceeds 10% by mass, wherein the content of solvent B2 in the sublimation film forming composition is greater than the content of solvent A2, and the boiling point is lower than the boiling point of the aforementioned sublimable substance at 1 atmosphere and lower than the boiling point of solvent A2, is hereinafter referred to as the sublimation film forming composition of the second embodiment.

[0160] In this embodiment, solvent A2 is selected from the aforementioned solvent A. The boiling point of the sublimable substance at 1 atmosphere - the boiling point of solvent A2 can be 0°C, or it can be above 0°C but below 5°C, or it can be above 5°C but below 200°C. Furthermore, from the viewpoint of easily solidifying the sublimable substance, for example, preferably above 0°C but below 200°C, and even more preferably above 5°C but below 200°C.

[0161] Solvent B2 is a solvent that can promote the formation of sublimation films by evaporating earlier than solvent A2. As long as its boiling point is lower than that of solvent A2 and the boiling point of the sublimation substance, the saturated solubility of the sublimation substance is not particularly limited. It can be used even if the saturated solubility of the sublimation substance in solvent A2 is lower than that of the aforementioned sublimation substance.

[0162] In this embodiment, the content of solvent B2 in the sublimable film-forming composition is greater than the content of solvent A2. Preferably, solvent B2 can also be included as a main component in the sublimable film-forming composition. The lower limit of the content of solvent B2 in the sublimable film-forming composition as a main component is, for example, 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more. The upper limit of the content of solvent B2 can also be, for example, 99.8% by mass or less, 99.5% by mass or less, or 99% by mass or less.

[0163] In a sublimable film-forming composition containing solvent B2 as the main component, the content of solvent A2 is, for example, 0.1% to 30% by mass, preferably 0.5% to 10% by mass.

[0164] In the second embodiment of the sublimable film forming composition, by comprising at least one of each of solvent A2 and solvent B2, solvent B2 relatively evaporates, and the heat of vaporization promotes the formation of the sublimable film (solidification of the sublimable substance). At this time, the sublimable substance and solvent A2 remain, but since solvent A2 can dissolve the sublimable substance in these residues, it is conceivable that excessive initial precipitation of the sublimable substance can be suppressed. Therefore, after the sublimable film is formed and removed, in addition to reducing the pattern collapse rate, strip collapse can also be suppressed.

[0165] By including solvent B2 as the main component in the sublimation film forming composition of the second embodiment, the film forming time of the sublimation film can be reduced, and the manufacturing cost of the substrate can also be suppressed.

[0166] Furthermore, the difference between the boiling point of solvent A2 and the boiling point of solvent B2 is not particularly limited, as long as solvent A2 can remain after solvent B2 evaporates. However, it is preferably above 5°C, above 10°C, above 15°C, and above 20°C. On the other hand, it can also be below 200°C or below 150°C.

[0167] The upper limit of the boiling point of solvent B2 is, for example, below 85°C, preferably below 80°C, and even more preferably below 70°C.

[0168] On the other hand, the lower limit of the boiling point of solvent B2 can be, for example, above 15°C, preferably above 20°C, and even more preferably above 25°C.

[0169] In the case where the first embodiment includes two or more solvents A1, as an example, the second and subsequent solvents A1 may be selected from those to which the saturated solubility of the sublimable substance in the solvent A1 is 40% by mass or more and the boiling point is 200°C or less. Preferably, they may also be selected from those to which the saturated solubility of the sublimable substance is 75% by mass or more and the boiling point is 180°C or less.

[0170] In the case where the second embodiment includes two or more solvents A2 and / or solvent B2, as an example, the second or subsequent solvent A2 may be selected from those in which the saturated solubility of the sublimable substance in solvent A2 is 40% by mass or more and the boiling point is below the boiling point of the sublimable substance; preferably, it may be selected from those in which the saturated solubility of the sublimable substance is 50% by mass or more and the boiling point is below 210°C; more preferably, it may be selected from those in which the saturated solubility of the sublimable substance is 60% by mass or more and the boiling point is below 200°C; and even more preferably, it may be selected from those in which the saturated solubility of the sublimable substance is 75% by mass or more and the boiling point is below 180°C.

[0171] Furthermore, when there are two or more solvents A2 and one or more solvents B2, it is preferable that the solvent with a smaller boiling point difference among the solvents A2 is more likely to remain when solvent B2 evaporates. The aforementioned boiling point difference is not particularly limited as long as it allows solvent A2 to function effectively. However, for example, the difference between the highest and lowest boiling point of the two or more solvents A2 should preferably be below 20°C, more preferably below 15°C, and even more preferably below 10°C. That is, the difference in boiling point between the second or subsequent solvents A2 and the first solvent A1 can, for example, be below 10°C, below 15°C, or below 20°C. Furthermore, in this case, the boiling point of solvent B2 is lower than the lowest boiling point of solvent A2.

[0172] Furthermore, the second and subsequent solvents B2 can also be selected from those with a boiling point of, for example, below 83°C—preferably below 80°C, and even more preferably below 70°C.

[0173] Solvents used as components of sublimable films include: hydrocarbons, ethers, alcohols, ketones, esters, sulfides, nitrogen-containing compounds, etc. These solvent species may also have one or more halogen atoms, such as fluorine or chlorine, within their molecules. They may be used alone or in combination of two or more.

[0174] Hydrocarbons can include, for example, alkanes or cycloalkanes with 4 to 10 carbon atoms, alkenes or cycloalkenes with 4 to 10 carbon atoms, and aromatics with 6 to 10 carbon atoms.

[0175] Specific examples of hydrocarbons include: pentane, 3-methylpentane, hexane, heptane, octane, nonane, decane, isododecane, cyclopentane, cyclohexane, methylcyclohexane, 1,1-dichloroethane, 1,2-dichloroethane, 1,2-dichloroethylene, cis-1-chloro-3,3,3-trifluoropropene (1233Z), trans-1-chloro-3,3,3-trifluoropropene (1233E), toluene, benzene, xylene, etc.

[0176] Ethers can be, for example, chain-like or cyclic ether compounds with 3 to 10 carbon atoms.

[0177] Specific examples of ethers include: tetrahydrofuran, diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, tributyl methyl ether, dioxane, 1,1,1,2,2,3,3,4,4-nonafluorobutyl methyl ether (Novec 7100), ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, etc.

[0178] Alcohols can be, for example, primary, secondary, and tertiary alcohols with 1 to 10 carbon atoms.

[0179] Specific examples of alcohols include: methanol, ethanol, 1-propanol, 2-propanol (IPA), 1-butanol, 2-butanol, cyclopentanol, cyclohexanol, 2-methyl-2-butanol, 4-methyl-2-pentanol, ethylene glycol, propylene glycol, 2,2,2-trifluoroethanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 1,3-propanediol, etc.

[0180] Ketones can be, for example, ketone compounds with 3 to 6 carbon atoms.

[0181] Specific examples of ketones include acetone, acetone, methyl ethyl ketone, methyl propyl ketone, and methyl butyl ketone.

[0182] Examples of esters include chain or cyclic ester compounds with 3 to 6 carbon atoms.

[0183] Specific examples of esters include: methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, butyl acetate, methyl lactate, ethyl lactate, ethyl acetate, ethyl trifluoroacetate, γ-butyrolactone, ethylene glycol acetate, propylene glycol acetate, ethylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether acetate.

[0184] Examples of sub-sands include dimethyl sands, etc.

[0185] Examples of nitrogen-containing compounds include: methylamine, N,N-dimethylmethylamine, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, pyridine, etc.

[0186] One or more of the above solvents may be selected as solvent A1, solvent A2, solvent B1 and solvent B2, respectively, depending on the sublimation substances contained in the sublimation film forming composition.

[0187] From the viewpoint of balancing high solubility for sublimable substances and miscibility with substances such as water or alcohols with 3 or fewer carbon atoms that are often used as residual liquids on the substrate surface, solvents A1 and A2 are preferably at least one from the group consisting of ethers, alcohols, ketones, esters, and hydrocarbons having one or more halogen atoms such as fluorine or chlorine atoms in their molecules. Specific examples of such solvents include: tetrahydrofuran, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-2-butanol, acetone, methyl acetate, ethyl acetate, 1,1-dichloroethane, 1,2-dichloroethane, 1,2-dichloroethylene, cis-1-chloro-3,3,3-trifluoropropene, and trans-1-chloro-3,3,3-trifluoropropene. Furthermore, the following are preferred examples: methanol, ethanol, 1-propanol, 2-propanol, 2-butanol, 2-methyl-2-butanol, acetone, methyl acetate, cis-1-chloro-3,3,3-trifluoropropene and trans-1-chloro-3,3,3-trifluoropropene, etc.

[0188] From the viewpoint of balancing high volatility and miscibility with solvents B1 and B2, which are often used as residual liquids on the substrate surface, such as water or alcohols with 3 or fewer carbon atoms, it is preferable that they include at least one solvent from the group consisting of hydrocarbons, ethers, alcohols, ketones, and esters. Specific examples of such solvents include: pentane, 3-methylpentane, hexane, heptane, cyclopentane, cyclohexane, methylcyclohexane, 1,1-dichloroethane, 1,2-dichloroethane, 1,2-dichloroethylene, cis-1-chloro-3,3,3-trifluoropropene, trans-1-chloro-3,3,3-trifluoropropene, toluene, benzene, xylene, diethyl ether, dipropyl ether, diisopropyl ether, tetrahydrofuran, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, acetone, methyl acetate, and ethyl acetate, etc. Among the preferred examples are: pentane, hexane, cyclopentane, cyclohexane, methylcyclohexane, cis-1-chloro-3,3,3-trifluoropropene, trans-1-chloro-3,3,3-trifluoropropene, diethyl ether, tetrahydrofuran, methanol, ethanol, 1-propanol, 2-propanol, acetone, and methyl acetate, etc.

[0189] (Other solvents)

[0190] The sublimation film forming composition may, to the extent that it does not impair the effects of the present invention, further include solvent C in addition to the above-mentioned solvents A1, A2, B1, and B2, for the purpose of adjusting the wettability to the substrate and / or the raised and recessed patterns, or it may be configured in a manner that substantially does not contain solvent C in the sublimation film forming composition.

[0191] Examples of solvents C include: water, hydrocarbons, esters, ethers, ketones, sulfoxide solvents, alcohols, derivatives of polyols, nitrogen-containing compounds, etc., which refer to solvents that are not among the solvents mentioned above.

[0192] Examples of the aforementioned hydrocarbons include toluene, benzene, xylene, pentane, 3-methylpentane, hexane, heptane, octane, nonane, decane, cyclopentane, cyclohexane, methylcyclohexane, 1,1-dichloroethane, 1,2-dichloroethane, 1,2-dichloroethylene, cis-1-chloro-3,3,3-trifluoropropene (1233Z), and trans-1-chloro-3,3,3-trifluoropropene (1233E), etc., and esters mentioned above. Examples include ethyl acetate, butyl acetate, methyl acetate, n-propyl acetate, isopropyl acetate, methyl lactate, ethyl lactate, ethyl acetate, trifluoroethyl acetate, and γ-butyrolactone. Examples of the above-mentioned ethers include diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, tributyl methyl ether, tetrahydrofuran, dioxane, and 1,1,1,2,2,3,3,4,4-nonafluorobutyl methyl ether (Novec). Examples of ketones include acetone, acetone, methyl ethyl ketone, methyl propyl ketone, and methyl butyl ketone. Examples of sulfoxide solvents include dimethyl sulfoxide. Examples of alcohols include methanol, ethanol, 1-propanol, 2-propanol, butanol, 2-methyl-2-butanol, 4-methyl-2-pentanol, ethylene glycol, propylene glycol, 2,2,2-trifluoroethanol, 1,1,1,3,3,3-hexafluoro-2-propanol, and 1,3-propanediol. Examples of polyol derivatives include diethylene glycol. Examples of nitrogen-containing compounds include monoethyl ether of alcohol, monomethyl ether of ethylene glycol, monobutyl ether of ethylene glycol, monomethyl ether of propylene glycol, monoethyl ether of propylene glycol, diethyl glycol monoethyl ether ester of diethylene glycol, monomethyl ether ester of ethylene glycol, monobutyl ether ester of ethylene glycol, monomethyl ether ester of propylene glycol, and monoethyl ether ester of propylene glycol. Other examples include methylamine, N,N-dimethylmethylamine, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and pyridine. Examples of solvents not belonging to solvents A1, A2, B1, and B2 include these.

[0193] The appropriate lower limit for the total solvent content in the sublimable film-forming composition is, for example, 20% by mass or more, preferably 50% by mass or more, and even more preferably 60% by mass or more. This makes it easier to obtain the cooling effect caused by the heat of vaporization of the solvent, thus promoting the solidification of the sublimable substance.

[0194] On the other hand, the appropriate upper limit for the total content of solvent in the sublimable film forming composition is, for example, 99.9% by mass or less, preferably 99.5% by mass or less, and even more preferably 99.2% by mass or less. This makes it easier for the sublimable material to solidify uniformly on the substrate, which is preferable.

[0195] The sublimable film-forming composition is in a liquid state, preferably a solution, at least when supplied to the substrate surface. From the viewpoint of easy and stable supply, it is preferable to be liquid (preferably a solution) at -15°C to 50°C, and even more preferable to be liquid (preferably a solution) at 0°C to 50°C. Furthermore, from the viewpoint of simplifying the structure of the device, such as eliminating the need for heat preservation or heating of the storage container or the pipetting mechanism used to supply to the aforementioned nozzles 4 and 5, it is particularly preferable to be liquid (preferably a solution) at 20°C to 50°C. Moreover, from the viewpoint of simplifying processing (manufacturing, storage, handling, etc.), it is preferable to be liquid (preferably a solution) at -15°C to 50°C, and even more preferable to be liquid (preferably a solution) at 0°C to 40°C. Furthermore, from the viewpoint of simplifying the structure of the device, such as eliminating the need for heat preservation or heating of the pipetting mechanism or storage container, it is particularly preferable to be liquid (preferably a solution) at 20°C to 30°C.

[0196] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations may be employed. Furthermore, the present invention is not limited to the embodiments described above, and modifications and alterations that achieve the objectives of the present invention are all included in the present invention.

[0197] Furthermore, in this specification, ordinal numbers such as "1st", "2nd", "3rd" or symbols such as "A" and "B", unless otherwise specified, are used only to distinguish components with the same name and do not imply any specific characteristics of the components (such as order or importance).

[0198] Example

[0199] The present invention will be described in detail below with reference to the embodiments, but the present invention is not limited to the description of these embodiments.

[0200] <Substrate Manufacturing>

[0201] First, a silicon substrate with an uneven structure formed on its surface is cut into a size of 1 cm × 1.5 cm to prepare an evaluation substrate. The uneven structure has a plurality of approximately cylindrical protrusions with an aspect ratio of 22 and a pattern width of 19 nm at a distance of 90 nm between them (the total distance between the width of the protrusion and the adjacent spacing of the protrusions).

[0202] Next, the surface of the uneven structure of the evaluation substrate is dry-cleaned by UV / O3 irradiation.

[0203] Next, the spin bowl of the spin coater is covered with a polyethylene glove bag that has gas inlets and outlets. The glove bag is constructed in a way that allows for control of the internal gas environment.

[0204] Next, the evaluation substrate is placed in a glove bag and a spin coater is used to supply 2-propanol to create a state in which the recesses in the uneven structure are filled with liquid (2-propanol) (preparation process).

[0205] Furthermore, by using the aforementioned glove bag, it is possible to conduct simulated experiments that mimic the chamber of an actual semiconductor manufacturing device. The pressure inside the glove bag is made to be the same as atmospheric pressure (approximately 1 atmosphere).

[0206] Next, the gas environment inside the aforementioned glove bag is adjusted to any one of the following gas environments A, B, and C. The dew point temperature of gas environments A, B, and C is determined by measuring the relative humidity of the gas supplied to the glove bag and converting it to dew point temperature. Specifically, using the temperature-water saturated vapor pressure correspondence table disclosed in JIS Z 8806:2001, the relative humidity of the gas supplied to the glove bag is first converted to water vapor pressure. Then, the temperature at which this water vapor pressure becomes saturated vapor pressure is defined as the dew point temperature of the gas supplied to the glove bag.

[0207] (Gas Environment A: Nitrogen gas environment, dew point temperature -20℃)

[0208] Nitrogen gas (dew point temperature -20°C) supplied by a pressure swing adsorption (PSA) nitrogen supply system is introduced into the glove bag through the gas inlet at a flow rate of 20 L / min for approximately 30 to 60 minutes. Simultaneously, exhaust gas is released through the gas outlet of the glove bag, thereby adjusting the dew point temperature inside the glove bag to match that of the supplied nitrogen gas.

[0209] (Gas Environment B: Mixture of nitrogen and air, dew point temperature 6℃)

[0210] After supplying the glove bag with ambient air (temperature 25°C, relative humidity 60%: equivalent to dew point temperature 17°C), supply nitrogen gas, which is the same as the above-mentioned gas environment A, while simultaneously venting the gas. When the relative humidity reaches 30% (equivalent to dew point temperature 6°C), stop the supply of nitrogen gas and the venting of the gas, close the gas inlet and outlet of the glove bag, and wait for about 10 minutes.

[0211] (Gas environment C: air, dew point temperature 17℃)

[0212] Supply indoor air (temperature 25°C, relative humidity 60%: equivalent to dew point temperature 17°C) into the glove bag.

[0213] Next, the evaluation substrate is rotated at 100 revolutions per minute using a spin coater. After rotating for 5 to 10 seconds, the rotation is maintained, and the sublimable film-forming composition in solution at 23°C is dropped onto the surface of the uneven structure, replacing the residual liquid of 2-propanol as described above with the sublimable film-forming composition (supply process).

[0214] In the above supply process, any one of the following sublimation film forming components 1 to 4 is used as the sublimation film forming component.

[0215] • Sublimable film-forming composition 1: A composition obtained by mixing neopentyl alcohol and 1233Z at a mass ratio of 10:90. The water content relative to 100% by mass of the sublimable substance is 0.5% by mass.

[0216] • Sublimation film-forming composition 2: A composition obtained by mixing camphor and IPA at a mass ratio of 1:99. The water content relative to 100% by mass of the sublimation substance is 0.8% by mass.

[0217] • Sublimable film-forming composition 3: A composition obtained by mixing HFCPA and Novec 7100 at a mass ratio of 80:20. The water content relative to 100% by mass of the sublimable substance is 0.3% by mass.

[0218] • Sublimable film-forming composition 4: A composition obtained by mixing HDCP and heptane at a mass ratio of 12:88. The water content relative to 100% by mass of the sublimable substance is 0.2% by mass.

[0219] (Sublimable substances)

[0220] Neopentyl alcohol: Boiling point 114℃, heat of solidification 22 J / g

[0221] Camphor: Boiling point 204℃, heat of solidification 38 J / g

[0222] HFCPA (1,1,2,2,3,3,4-heptafluorocyclopentane): Boiling point 83℃, heat of solidification 17 J / g

[0223] • HDCP (dicyclopentadiene): Boiling point 195℃, heat of solidification 13 J / g

[0224] (solvent)

[0225] ·1233Z (cis-1-chloro-3,3,3-trifluoropropene): Boiling point 39°C, saturated solubility in neopentyl alcohol 78% by mass

[0226] • IPA: Boiling point 82℃, saturated solubility of camphor 62% by mass

[0227] Novec 7100: Boiling point 61℃, saturated solubility of HFCPA ≥ 98% by mass.

[0228] • Heptane: Boiling point 98℃, saturated solubility of HDCP 86% by mass

[0229] In addition, saturated solubility refers to the saturated concentration of sublimable substances dissolved in a solvent, as measured below.

[0230] First, prepare a mixture of sublimable substance and solvent at a mass ratio of approximately 3:1, heat it to 40°C, and then cool it to room temperature (approximately 25°C). At room temperature, the mixture exists as a coexistence of solid and liquid. Take 10 μL of the liquid portion using a microsyringe, dilute it 100 times (volume ratio) with dilution solvent, and analyze it using gas chromatography. The result is converted to a mass ratio and determined as the saturated solubility (mass %). If no sublimable substance precipitates at room temperature and the solution is homogeneous, increase the amount of sublimable substance relative to the solvent and repeat the same operation. Furthermore, if the liquid portion is too small to be taken using a microsyringe at room temperature, increase the amount of solvent relative to the sublimable substance and repeat the same operation. The mass ratio calculation for gas chromatography is performed as follows: A capillary column (model TC-1, manufactured by GL Sciences Inc., 30 m in length, 5 μm in liquid phase thickness, 0.32 mm in inner diameter) is installed in a Shimadzu GC-2010 gas chromatograph and detected by an FID detector. The mass ratio is then converted from the area ratio of the diluent prepared by dissolving 1% by mass of the sublimable substance in the solvent each time. The diluent used in gas chromatography must be selected to produce a peak of sublimable substance and solvent sufficiently far from the analyte in the gas chromatography process; specifically, a solvent with a development time distance of 0.1 minutes or more on the chromatogram should be selected.

[0231] Next, maintaining the rotation speed in the supply process, after the aforementioned sublimation film forming composition has been diffused onto the substrate, the formation of the coating film is visually confirmed. Then, rotation continues to visually confirm the formation of the sublimation film (the solidified film of the sublimation substance).

[0232] At this time, under atmospheric pressure (approximately 1 atmosphere), the surface temperatures of the coated film and the sublimable film were measured using a non-contact radiation thermometer (MOTHERTOOL CO., LTD., MT-11). As a result, with the surface temperature of the substrate before coating at approximately 22°C, the surface temperature of the film formed from composition 1 of the sublimable film began to decrease from the start of solvent evaporation, dropping to a minimum of approximately 12°C (minimum temperature T), and then slowly increased as the sublimable substance solidified, ultimately reaching a surface temperature of approximately 20°C (final temperature T up).

[0233] Next, continue rotating it until the aforementioned sublimation film is visually confirmed to have disappeared.

[0234] Evaluation of Pattern Collapse Rate

[0235] The obtained substrates were observed using a scanning electron microscope (SEM) (SU8010, manufactured by Hitachi High-Technologies Corporation) to evaluate the proportion of protrusion collapse (pattern collapse) in the uneven structure (pattern collapse rate).

[0236] The "pattern collapse rate" was measured using SEM (Self-Electron Microscopy). Electron microscope images (secondary electron images) were taken at a magnification where 500-600 protrusions would enter the field of view. The number of collapsed protrusions in the acquired images was counted, and the percentage of each collapsed protrusion in the field of view was calculated. Furthermore, multiple electron microscope images were taken while changing the location of the evaluation substrate, and the pattern collapse rate was calculated for each image. The values ​​were rounded to the nearest 10, following JIS Z 8401.

[0237] The results obtained are shown in Table 1. The table records the number of images with a pattern collapse rate of 0-30%, 40-60%, and 70-100%, respectively.

[0238] Furthermore, when repeatedly manufacturing the substrate, the probability of the pattern collapse rate being 0-30% is calculated as an evaluation of reproducibility.

[0239] Table 1 Substrate fabrication method unit Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Sublimation drying process (During solidification) gas environment A B A A A C C C C Dew point temperature T dp ℃ -20 6 -20 -20 -20 17 17 17 17 Sublimation membrane form Composition 1 1 2 3 4 1 2 3 4 Minimum temperature T min ℃ 12 12 13 15 13 12 13 15 13 Final temperature T up ℃ 20 20 20 20 20 20 20 20 20 Pattern collapse rate 0~30% open 9 9 9 6 6 4 0 0 0 40~60% 0 0 0 0 0 1 0 3 2 70~100% 0 0 0 0 0 4 9 6 7 Reproducibility % 100 100 100 100 100 44 0 0 0

[0240] The substrate manufacturing methods in Examples 1-5 yielded experimental results with a pattern collapse rate of less than 30% as observed through SEM images with a probability of more than 50%. Compared with Comparative Examples 1-4, this revealed a result that could stably suppress pattern collapse.

[0241] This application claims priority to Japanese Patent Application No. 2021-150186, filed on September 15, 2021, all of which are incorporated herein by reference.

[0242] 1: Chamber 2: Platform 3: Rotating mechanism 4, 5: Nozzle 6: Gas Inlet 7: Gas outlet 10:Substrate 20: Concave-convex structure 22:convex part 24: concave part 30: Sublimation film-forming components 50: Membrane 100: Processing device

Claims

1. A method for manufacturing a substrate, comprising: a preparation step of preparing a substrate having a surface with an uneven structure; a placement step of placing the substrate, in which at least a recess in the uneven structure is filled with a cleaning liquid, in a chamber; a supply step of supplying a sublimable film forming composition comprising a sublimable substance and a solvent to at least a recess in the substrate placed in the chamber; and a sublimation drying step of solidifying a film formed from the supplied sublimable film forming composition and removing it by sublimation; wherein in the sublimation drying step, when the dew point temperature of the gas environment in the chamber at 1 atmosphere is defined as Tdp℃ and the lowest temperature of the film on the surface during the solidification process is defined as Tmin℃, Tdp and Tmin are controlled to satisfy Tmin-Tdp≧20.

2. The method for manufacturing a substrate as described in claim 1, wherein in the aforementioned sublimation drying process, after the surface temperature of the aforementioned film reaches the aforementioned minimum temperature before the solidification process, the final temperature at which the temperature rise stops is set as Tup℃, and Tdp and Tup are controlled such that Tup > Tdp.

3. The method for manufacturing a substrate as claimed in claim 1, comprising a process selected from one or more of the following: "supplying a dry gas to the interior of the aforementioned chamber or replacing the gas inside the aforementioned chamber with the aforementioned dry gas in a process preceding the aforementioned supply process", "contacting the aforementioned dry gas to the surface of the aforementioned film in the aforementioned sublimation drying process", and "heating the aforementioned substrate in the aforementioned sublimation drying process".

4. The method for manufacturing a substrate as claimed in claim 1, wherein the aforementioned sublimation drying process includes a process of "supplying a drying gas to the interior of the aforementioned chamber and discharging the gas from the interior of the aforementioned chamber during at least the solidification process of the aforementioned film".

5. The method for manufacturing a substrate as described in claim 3, wherein the aforementioned drying gas includes a drying inert gas.

6. A method for manufacturing a substrate as described in claim 1, comprising a solvent A1, wherein the solvent A1 has a saturated solubility of the aforementioned sublimable substance exceeding 10% by mass and a boiling point that is more than 5°C lower than the boiling point of the aforementioned sublimable substance at 1 atmosphere.

7. A method for manufacturing a substrate as claimed in claim 1, comprising: solvent A2, wherein the saturated solubility of the aforementioned sublimable substance exceeds 10% by mass; and solvent B2, wherein the content in the sublimable film forming composition is greater than the content of the aforementioned solvent A2, and the boiling point is less than the boiling point of the aforementioned sublimable substance at 1 atmosphere and less than the boiling point of the aforementioned solvent A2.

8. A method for manufacturing a substrate as described in claim 1, wherein the heat of solidification of the aforementioned sublimation material is 200 J / g or less.

9. A method for manufacturing a substrate as described in claim 1, wherein the aforementioned cleaning solution contains an alcohol having 3 or fewer carbon atoms.

10. A method for manufacturing a substrate as claimed in claim 1, wherein the substrate has the aforementioned uneven structure on the aforementioned surface with a pattern size of 30 nm or less.

11. A method for manufacturing a substrate as claimed in claim 10, wherein the substrate has the aforementioned uneven structure on the aforementioned surface with a pattern size of 20 nm or less.

12. A method for manufacturing a substrate as claimed in claim 1, wherein the aforementioned sublimation film forming composition is free of water or contains water at a content of 10% by mass or less relative to 100% by mass of the aforementioned sublimation material.

13. A sublimation drying method, comprising a sublimation drying step, wherein the sublimation drying step solidifies a film composed of a sublimable film containing a sublimable substance and removes it by sublimation; wherein in the aforementioned sublimation drying step, when the dew point temperature of the gas environment surrounding the aforementioned film at 1 atmosphere is defined as Tdp℃, and the lowest temperature of the aforementioned film at the surface temperature before the solidification process is defined as Tmin℃, Tdp and Tmin are controlled such that Tmin-Tdp≧20.

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