TWI742387B - Substrate processing method, substrate processing apparatus and pre-drying processing liquid - Google Patents

Abstract

A pre-drying processing liquid containing a sublimable substance that changes to gas without passing through to a liquid and a solvent in which the sublimable substance dissolves is supplied to a front surface of a substrate on which a pattern has been formed. Thereafter, the solvent is evaporated from the pre-drying processing liquid on the front surface of the substrate to thereby form a solidified body containing the sublimable substance on the front surface of the substrate. Thereafter, the solidified body is sublimated and thereby removed from the front surface of the substrate. A value acquired by multiplying a ratio of the thickness of the solidified body to the height of the pattern by 100 is greater than 76 and less than 219.

Description

Substrate processing method, substrate processing device and treatment liquid before drying

The present invention relates to a substrate processing method and a substrate processing apparatus for processing a substrate, and a pre-drying treatment liquid supplied to the surface of the substrate before the surface of the substrate is dried. The substrates to be processed include, for example, semiconductor wafers, liquid crystal display devices, or organic EL (electroluminescence, electroluminescence) display devices, such as FPD (Flat Panel Display) substrates, optical disk substrates, magnetic disk substrates, and magneto-optical disks. Substrates, photomask substrates, ceramic substrates, solar cell substrates, etc.

In the manufacturing steps of semiconductor devices, liquid crystal display devices, etc., substrates such as semiconductor wafers or glass substrates for liquid crystal display devices are processed as needed. Such processing includes supplying a processing liquid such as a chemical liquid or a rinse liquid to the substrate. After supplying the processing liquid, the processing liquid is removed from the substrate, and the substrate is dried. In a single-piece substrate processing apparatus that processes substrates one by one, spin drying is performed in which the substrate is dried by removing the liquid attached to the substrate by using the high-speed rotation of the substrate.

When a pattern is formed on the surface of the substrate, when the substrate is dried, the force generated by the surface tension of the processing liquid attached to the substrate may be applied to the pattern, causing the pattern to collapse. As a countermeasure, a method of supplying a liquid with low surface tension such as IPA (Isopropyl Alcohol) to the substrate, or supplying a hydrophobizing agent that makes the contact angle of the liquid with respect to the pattern close to 90 degrees is used to the substrate. However, even if IPA or a hydrophobizing agent is used, the collapse force of the pattern collapse will not become zero. Therefore, depending on the strength of the pattern, even if such countermeasures are taken, the collapse of the pattern may not be sufficiently prevented.

In recent years, as a technique to prevent pattern collapse, sublimation drying has attracted attention. For example, in JP 2012-243869 A, a substrate processing method and a substrate processing apparatus for sublimation drying are disclosed. In the sublimation drying described in JP 2012-243869 A, a solution of a sublimable substance is supplied to the upper surface of a substrate, and the DIW on the substrate is replaced with a solution of the sublimable substance. Thereafter, the solvent of the sublimable substance is dried to precipitate the sublimable substance. Thereby, a film containing a solid sublimable substance is formed on the upper surface of the substrate. In paragraph 0028 of JP 2012-243869 A, it is stated that "the film thickness "t" of the film containing the sublimable substance is preferably as thin as possible within the range that sufficiently covers the convex portion 101 of the pattern". The substrate is heated after forming a film containing a solid sublimable substance. Thereby, the sublimable substance on the substrate is sublimated and removed from the substrate.

Generally speaking, sublimation drying has a lower pattern collapse rate than previous drying methods such as spin drying in which liquid is removed by high-speed rotation of the substrate or IPA drying using IPA. However, if the strength of the pattern is extremely low, even if the sublimation drying is performed, the collapse of the pattern may not be sufficiently prevented. According to research conducted by the inventors, one of the reasons for this is found to be the thickness of the solidified body containing the sublimable substance. In JP 2012-243869 A, it is only stated that "the film thickness "t" of the film containing the sublimable substance is preferably as thin as possible within the range that sufficiently covers the convex portion 101 of the pattern." The thickness of the material film has not been fully considered.

One of the objects of the present invention is to provide a substrate processing method, a substrate processing apparatus, and a pre-drying treatment solution that can reduce pattern collapse generated when the substrate is dried by sublimation drying.

An embodiment of the present invention provides a substrate processing method, comprising: a pre-drying treatment liquid supply step of supplying a pre-drying treatment liquid to the surface of a substrate on which a pattern is formed, the pre-drying treatment liquid containing changes without passing through the liquid A solution of a gaseous sublimable substance and a solvent that dissolves each other with the sublimable substance; the solidified body forming step is performed by evaporating the solvent from the pre-drying treatment liquid on the surface of the substrate on the surface of the substrate A solidified body containing the sublimable substance is formed on the upper surface; and a sublimation step, which removes the solidified body from the surface of the substrate by sublimating the solidified body; and the thickness of the solidified body after a hundred times relative to the height of the pattern The value of the ratio exceeds 76 and does not reach 219.

According to this method, the pre-drying treatment liquid containing the sublimable substance corresponding to the solute and the solvent is supplied to the surface of the patterned substrate. After that, the solvent was evaporated from the pre-drying treatment liquid. Thereby, a solidified body containing sublimable substances is formed on the surface of the substrate. Thereafter, the solidified body on the substrate is changed into a gas without passing through the liquid. Thereby, the solidified body is removed from the surface of the substrate. Therefore, compared with the previous drying methods such as spin drying, the collapse rate of the pattern can be reduced.

When the solvent is evaporated from the pre-drying treatment liquid, a solidified body containing sublimable substances is formed on the surface of the substrate. If the value of the ratio of the thickness of the solidified body after a hundred times to the height of the pattern is defined as the embedding rate, the embedding rate at the point when the solidified body is formed exceeds 76 and does not reach 219. If the embedding rate is outside this range, depending on the strength of the pattern, the number of collapses of the pattern may increase. Conversely, if the embedding rate is within this range, even if the strength of the pattern is low, the number of collapses of the pattern can be reduced. Therefore, even if the strength of the pattern is low, the collapse rate of the pattern can be reduced.

In the above-mentioned embodiment, at least one of the following characteristics may be added to the above-mentioned substrate processing method.

The above-mentioned sublimable substance includes at least one of camphor and naphthalene.

The above-mentioned solvent includes at least one of IPA (isopropanol), acetone, and PGEE (propylene glycol monoethyl ether).

The solvent is IPA, and the mass percentage concentration of the sublimable substance in the pre-drying treatment liquid exceeds 0.62 and does not reach 2.06.

The solvent is acetone, and the mass percentage concentration of the sublimable substance in the pre-drying treatment liquid exceeds 0.62 and is 0.96 or less.

The solvent is PGEE, and the mass percentage concentration of the sublimable substance in the pre-drying treatment liquid exceeds 3.55 and is 6.86 or less.

The drying pretreatment liquid supplied to the surface of the substrate in the drying pretreatment liquid supply step includes the sublimable substance containing a hydrophobic group, the solvent, and a hydrophobic group and a hydrophilic group, and the hydrophilicity is higher than the sublimation property. The solution of the adsorbed substance of the substance.

According to this method, a pre-drying treatment liquid containing an adsorbent in addition to a sublimable substance and a solvent is supplied to the surface of the patterned substrate. After that, the solvent was evaporated from the pre-drying treatment liquid. Thereby, a solidified body containing sublimable substances is formed on the surface of the substrate. Thereafter, the solidified body on the substrate is changed into a gas without passing through the liquid. Thereby, the solidified body is removed from the surface of the substrate. Therefore, compared with the previous drying methods such as spin drying, the collapse rate of the pattern can be reduced.

Sublimation substances are substances that contain hydrophobic groups in their molecules. The adsorbent is a substance containing a hydrophobic group and a hydrophilic group in the molecule. The hydrophilicity of the adsorbed material is higher than that of the sublimable material. Regardless of whether the surface of the pattern is either hydrophilic or hydrophobic, or the surface of the pattern includes a hydrophilic part and a hydrophobic part, the adsorbent in the treatment solution before drying will be adsorbed on the surface of the pattern.

Specifically, when the surface of the pattern is hydrophilic, the hydrophilic group of the adsorbing substance in the treatment solution before drying is attached to the surface of the pattern, and the hydrophobic group of the sublimation substance in the treatment solution before drying is attached to the hydrophobic group of the adsorbing substance. base. Thereby, the sublimable substance is held on the surface of the pattern via the adsorbing substance. When the surface of the pattern is hydrophobic, at least the hydrophobic base of the sublimation substance is attached to the surface of the pattern. Therefore, no matter whether the surface of the pattern is either hydrophilic or hydrophobic, or the surface of the pattern includes a hydrophilic part and a hydrophobic part, the sublimable substance is kept on or near the surface of the pattern before the solvent evaporates. .

When the sublimable substance is hydrophilic and the surface of the pattern is hydrophilic, the sublimable substance is drawn to the surface of the pattern by electrical attraction. On the other hand, when the sublimable substance is hydrophobic and the surface of the pattern is hydrophilic, the attraction is weak or does not generate such attraction, so the sublimable substance is difficult to adhere to the surface of the pattern. Furthermore, when the sublimation substance is hydrophobic, the surface of the pattern is hydrophilic, and the interval between the patterns is extremely narrow, it is considered that a sufficient amount of the sublimation substance will not enter between the patterns. These phenomena also occur when the sublimation material is hydrophilic and the surface of the pattern is hydrophobic.

If the solvent is evaporated in a state where there is no sublimable substance on or near the surface of the pattern, the collapsing force will be applied to the pattern from the solvent in contact with the surface of the pattern, and the pattern may collapse. It is also believed that if the solvent is evaporated in a state where there is no sufficient amount of sublimable material between the patterns, the gaps between the patterns are not filled by the solidified body, and the patterns collapse. If the sublimation material is placed on the surface of the pattern or near the surface of the pattern before the solvent is evaporated, such collapse can be reduced. In this way, the collapse rate of the pattern can be reduced.

The hydrophilic group may be any one of a hydroxy group (hydroxyl group), a carboxyl group (COOH), an amine group (NH ₂ ), and a carbonyl group (CO), or may be other than these. The hydrophobic group may be any of a hydrocarbon group, an alkyl group (C _n H _2n+1 ), a cycloalkyl group (C _n H _2n+1 ), and a phenyl group (C ₆ H ₅ ), or may be other than these.

The above-mentioned adsorbent is a substance with sublimation property.

According to this method, not only the sublimable substance has sublimation property, but the adsorbed substance also has sublimation property. The adsorbed substance changes from a solid to a gas without passing through a liquid at room temperature or pressure. When at least a part of the surface of the pattern is hydrophilic, the solvent evaporates in a state where the adsorbent in the treatment solution before drying is adsorbed on the surface of the pattern. The adsorbed substance on the surface of the pattern changes from liquid to solid. As a result, a solidified body containing the adsorbed substance and the sublimable substance is formed. After that, the solid of the adsorbed substance changes into a gas without passing through the liquid on the surface of the pattern. Therefore, compared with the case where the liquid is vaporized on the surface of the pattern, the collapse force can be reduced.

The concentration of the adsorbed substance in the pre-drying treatment liquid is lower than the concentration of the solvent in the pre-drying treatment liquid.

According to this method, the pre-drying treatment liquid with a low concentration of adsorbed substances is supplied to the surface of the substrate. When at least a part of the surface of the pattern is hydrophilic, the hydrophilic group of the adsorbing substance is attached to the surface of the pattern, and a monomolecular film of the adsorbing substance is formed along the surface of the pattern. If the concentration of the adsorbed substance is relatively high, a plurality of monomolecular films will accumulate to form a laminated film of the adsorbed substance along the surface of the pattern. In this case, the sublimable substance is held on the surface of the pattern via the laminated film of the adsorbed substance. If the layered film of adsorbed substances is thicker, the sublimable substances entering between the patterns will decrease. Therefore, by reducing the concentration of adsorbed substances, more sublimable substances can enter between the patterns.

When at least a part of the surface of the pattern is hydrophilic, the concentration of the adsorbed substance in the pre-drying treatment solution may be the value of the monomolecular film of the adsorbed substance formed on the surface of the pattern, or it may exceed this The value of the value. In the former case, the sublimable substance is held on the surface of the pattern via the monomolecular film of the adsorbed substance. Therefore, even if at least a part of the surface of the pattern is hydrophilic, the sublimable substance can be placed near the surface of the pattern. Furthermore, since only the monomolecular film of the thinnest adsorbed substance is interposed between the sublimable substance and the pattern, a sufficient amount of the sublimable substance can enter between the patterns.

The hydrophobicity of the sublimable substance is higher than that of the adsorbed substance. The solubility of the sublimable substance with respect to oil is higher than the solubility of the adsorbed substance with respect to oil. In other words, the solubility of the sublimable substance with respect to water is lower than the solubility of the adsorbed substance with respect to water.

According to this method, a pre-drying treatment liquid containing a sublimable substance whose hydrophobicity is higher than that of an adsorbed substance is supplied to the surface of the substrate. Since either of the sublimable substance and the adsorbing substance contains a hydrophobic group, when at least a part of the surface of the pattern is hydrophobic, both the sublimable substance and the adsorbing substance can be attached to the surface of the pattern. However, the affinity between the sublimation substance and the pattern is higher than the affinity between the adsorption substance and the pattern, so the sublimation substance with more adsorption substance is attached to the surface of the pattern. In this way, more sublimable substances can be attached to the surface of the pattern.

Another embodiment of the present invention provides a substrate processing apparatus comprising: a pre-drying treatment liquid supply unit that supplies a pre-drying treatment liquid to the surface of a patterned substrate, and the pre-drying treatment liquid includes changes without passing through the liquid A solution of a gaseous sublimable substance and a solvent that dissolves each other with the sublimable substance; a solidified body forming unit that evaporates the solvent from the pre-drying treatment liquid on the surface of the substrate on the surface of the substrate A solidified body containing the sublimable substance is formed; and a sublimation unit that removes the solidified body from the surface of the substrate by sublimating the solidified body; and the ratio of the thickness of the solidified body to the height of the pattern after a hundred times The value exceeds 76 and does not reach 219. According to this structure, the same effect as the above-mentioned substrate processing method can be obtained.

Yet another embodiment of the present invention provides a pre-drying treatment liquid, which is a pre-drying treatment liquid supplied to the surface of the substrate before drying the surface of the substrate on which a pattern is formed. The sublimable substance and the solvent that dissolves each other with the sublimable substance, and the concentration of the sublimable substance is adjusted as follows: when the solvent is evaporated from the pre-drying treatment liquid on the surface of the substrate, the substrate When a solidified body containing the sublimable substance is formed on the surface, the ratio of the thickness of the solidified body to the height of the pattern after one hundred times exceeds 76 and does not reach 219. According to this structure, the same effect as the above-mentioned substrate processing method can be obtained.

The above-mentioned and other objects, features, and effects of the present invention can be clarified by referring to the accompanying drawings and the description of the embodiments described below.

In the following description, unless otherwise specified, the air pressure in the substrate processing apparatus 1 is set to maintain the air pressure in the clean room where the substrate processing apparatus 1 is installed (for example, 1 atmosphere or a value near it).

FIG. 1A is a schematic view of the substrate processing apparatus 1 of the first embodiment of the present invention viewed from above. FIG. 1B is a schematic diagram of the substrate processing apparatus 1 viewed from the side.

As shown in FIG. 1A, the substrate processing device 1 is a single-chip device that processes disk-shaped substrates W such as semiconductor wafers one by one. The substrate processing apparatus 1 is provided with: a load port LP for holding a carrier C holding a substrate W, a plurality of processing units 2 for processing the substrate W transported from the carrier C on the load port LP with a processing fluid such as a processing liquid or a processing gas. The transfer robot that transfers the substrate W between the carrier C on the load port LP and the processing unit 2 and the control device 3 that controls the substrate processing apparatus 1.

The transfer robot includes an indexer robot IR for carrying in and out of the substrate W with respect to the carrier C on the load port LP, and a center robot CR for carrying in and out of the substrate W with respect to the plurality of processing units 2. The indexing robot IR transfers the substrate W between the load port LP and the center robot CR, and the center robot CR transfers the substrate W between the indexing robot IR and the processing unit 2. The center robot CR includes a robot H1 that supports the substrate W, and the index robot IR includes a robot H2 that supports the substrate W.

The plurality of processing units 2 are formed with a plurality of towers TW arranged around the center robot CR in a plan view. Fig. 1A shows an example in which four towers TW are formed. The central robot CR can access any tower TW. As shown in FIG. 1B, each tower TW includes a plurality of (for example, 3) processing units 2 stacked one above the other.

FIG. 2 is a schematic view of the inside of the processing unit 2 included in the substrate processing apparatus 1 when viewed horizontally.

The processing unit 2 is a wet processing unit 2w that supplies the substrate W with a processing liquid. The processing unit 2 includes: a box-shaped chamber 4 with an internal space, and a rotating chuck that holds a substrate W horizontally in the chamber 4 and rotates around a vertical rotation axis A1 passing through the center of the substrate W 10. And the cylindrical processing cup 21 surrounding the rotating chuck 10 around the rotation axis A1.

The chamber 4 includes a box-shaped partition wall 5 provided with a loading/unloading port 5b through which the substrate W passes, and a baffle 7 for opening and closing the loading/unloading port 5b. The FFU 6 (fan filter unit) is arranged on the air blowing port 5 a provided on the upper part of the partition wall 5. The FFU6 always supplies clean air (air filtered by a filter) into the chamber 4 from the air supply port 5a. The gas in the chamber 4 is discharged from the chamber 4 through the exhaust duct 8 connected to the bottom of the processing cup 21. Thereby, a downflow of clean air is always formed in the chamber 4. The flow rate of the exhaust gas discharged to the exhaust duct 8 is changed according to the opening degree of the exhaust valve 9 arranged in the exhaust duct 8.

The rotating chuck 10 includes: a circular plate-shaped rotating base 12 held in a horizontal posture, a plurality of chuck pins 11 holding the substrate W in a horizontal posture above the rotating base 12, and a central portion of the rotating base 12 A rotating shaft 13 extending downward, and a rotating motor 14 that rotates the rotating base 12 and a plurality of chuck pins 11 by rotating the rotating shaft 13. The rotating chuck 10 is not limited to a clamping chuck in which a plurality of chuck pins 11 are brought into contact with the outer peripheral surface of the substrate W, and may be formed by making the back surface (lower surface) of the substrate W as a non-device forming surface ) A vacuum chuck that is adsorbed on the upper surface 12u of the rotating base 12 to hold the substrate W horizontally.

The processing cup 21 includes: a plurality of protective covers 24 for receiving the processing liquid discharged from the substrate W to the outside, a plurality of receiving cups 23 for receiving the processing liquid guided below by the plurality of protective covers 24, and surrounding a plurality of guards The cylindrical outer wall member 22 of the cover 24 and the plurality of cups 23. 2 shows an example in which four protective covers 24 and three cups 23 are provided, and the outermost cup 23 and the third protective cover 24 from the top are integrated.

The protective cover 24 includes a cylindrical portion 25 surrounding the rotating chuck 10 and an annular top wall 26 extending obliquely upward from the upper end of the cylindrical portion 25 toward the rotation axis A1. A plurality of top walls 26 are overlapped up and down, and a plurality of cylindrical parts 25 are arranged in a concentric shape. The annular upper end of the top wall 26 is equivalent to the upper end 24u of the protective cover 24 surrounding the substrate W and the rotating base 12 in a plan view. The plurality of cups 23 are respectively arranged below the plurality of cylindrical parts 25. The cup 23 forms an annular liquid receiving tank for receiving the treatment liquid guided to the lower side by the protective cover 24.

The processing unit 2 includes a protective cover elevating unit 27 for individually raising and lowering a plurality of protective covers 24. The protective cover lifting unit 27 positions the protective cover 24 at any position from the upper position to the lower position. FIG. 2 shows a state in which two protective covers 24 are arranged in an upper position, and the remaining two protective covers 24 are arranged in a lower position. In the upper position, the upper end 24u of the protective cover 24 is arranged above the holding position where the substrate W held by the spin chuck 10 is arranged. In the lower position, the upper end 24u of the protective cover 24 is arranged at a position lower than the holding position.

When supplying the processing liquid to the rotating substrate W, at least one protective cover 24 is arranged at the upper position. When the processing liquid is supplied to the substrate W in this state, the processing liquid supplied to the substrate W is thrown away to the periphery of the substrate W. The thrown away processing liquid collides with the inner surface of the protective cover 24 horizontally facing the substrate W and is guided to the cup 23 corresponding to the protective cover 24. Thereby, the processing liquid discharged from the substrate W is collected in the processing cup 21.

The processing unit 2 includes a plurality of nozzles for ejecting processing liquid to the substrate W held on the spin chuck 10. The plurality of nozzles include: a chemical liquid nozzle 31 for spraying a chemical liquid on the upper surface of the substrate W, a rinse liquid nozzle 35 for spraying a rinse liquid on the upper surface of the substrate W, and a pre-drying process for spraying a pre-drying treatment liquid on the upper surface of the substrate W A liquid nozzle 39 and a replacement liquid nozzle 43 that sprays a replacement liquid onto the upper surface of the substrate W.

The liquid medicine nozzle 31 may be a scanning nozzle that can move horizontally in the chamber 4, or a fixed nozzle that is fixed with respect to the partition wall 5 of the chamber 4. The same applies to the rinse liquid nozzle 35, the pre-drying treatment liquid nozzle 39, and the replacement liquid nozzle 43. FIG. 2 shows an example in which the chemical liquid nozzle 31, the rinse liquid nozzle 35, the pre-drying treatment liquid nozzle 39, and the replacement liquid nozzle 43 are scanning nozzles, and 4 nozzle moving units corresponding to the 4 nozzles are provided.

The chemical liquid nozzle 31 is connected to a chemical liquid pipe 32 that guides the chemical liquid to the chemical liquid nozzle 31. When the chemical liquid valve 33 installed in the chemical liquid pipe 32 is opened, the chemical liquid is continuously ejected downward from the ejection port of the chemical liquid nozzle 31. The chemical liquid sprayed from the chemical liquid nozzle 31 may include sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid, phosphoric acid, acetic acid, ammonia water, hydrogen peroxide water, organic acid (such as citric acid, oxalic acid, etc.), and organic alkali (such as TMAH: At least one liquid of tetramethylammonium hydroxide, etc.), a surfactant, and an anti-corrosion agent may be other liquids.

Although not shown, the chemical liquid valve 33 includes: a valve body provided with an internal flow path through which the chemical liquid flows and an annular valve seat surrounding the internal flow path, a valve body capable of moving relative to the valve seat, and a valve body An actuator that moves between the closed position where the valve body contacts the valve seat and the open position where the valve body leaves the valve seat. The same applies to other valves. The actuator can be a pneumatic actuator or an electric actuator, or an actuator other than these. The control device 3 opens and closes the liquid medicine valve 33 by controlling the actuator.

The chemical liquid nozzle 31 is connected to a nozzle moving unit 34 that moves the chemical liquid nozzle 31 in at least one of a vertical direction and a horizontal direction. The nozzle moving unit 34 makes the chemical liquid nozzle 31 perform between the processing position where the chemical liquid sprayed from the chemical liquid nozzle 31 is supplied to the upper surface of the substrate W, and the standby position of the chemical liquid nozzle 31 located around the processing cup 21 in a plan view. Move horizontally.

The washing liquid nozzle 35 is connected to a washing liquid pipe 36 that guides the washing liquid to the washing liquid nozzle 35. When the flushing fluid valve 37 installed in the flushing fluid pipe 36 is opened, the flushing fluid is continuously ejected downward from the ejection port of the flushing fluid nozzle 35. The rinse liquid sprayed from the rinse liquid nozzle 35 is, for example, pure water (DIW (Deionized Water)). The rinsing fluid can also be any one of carbonated water, electrolyzed ionized water, hydrogen water, ozone water, and hydrochloric acid water with a dilution concentration (for example, about 10-100 ppm).

The rinsing liquid nozzle 35 is connected to a nozzle moving unit 38 that moves the rinsing liquid nozzle 35 in at least one of the vertical direction and the horizontal direction. The nozzle moving unit 38 makes the rinse liquid nozzle 35 perform between the processing position where the rinse liquid sprayed from the rinse liquid nozzle 35 is supplied to the upper surface of the substrate W and the standby position where the rinse liquid nozzle 35 is located around the processing cup 21 in a plan view. Move horizontally.

The pre-drying treatment liquid nozzle 39 is connected to a pre-drying treatment liquid pipe 40 that guides the treatment liquid to the pre-drying treatment liquid nozzle 39. When the pre-drying treatment liquid valve 41 installed in the pre-drying treatment liquid piping 40 is opened, the pre-drying treatment liquid is continuously sprayed downward from the discharge port of the pre-drying treatment liquid nozzle 39. Similarly, the replacement liquid nozzle 43 is connected to a replacement liquid piping 44 that guides the replacement liquid to the replacement liquid nozzle 43. When the replacement liquid valve 45 installed in the replacement liquid piping 44 is opened, the replacement liquid is continuously ejected downward from the ejection port of the replacement liquid nozzle 43.

The pre-drying treatment liquid is a solution containing a sublimation substance equivalent to the solute and a solvent that dissolves the sublimation substance with each other. The sublimable substance can be a substance that changes from a solid to a gas without passing through a liquid at normal temperature (synonymous with room temperature) or normal pressure (pressure in the substrate processing apparatus 1, for example, 1 atmosphere or its vicinity). The solvent may be such a substance or other substances. That is, the pre-drying treatment liquid may contain two or more substances that change from a solid to a gas without passing through a liquid at normal temperature or normal pressure.

The sublimation substance can be, for example, 2-methyl-2-propanol (alias: tert-butyl alcohol, t-butyl alcohol, tertiary butyl alcohol) or cyclohexanol and other alcohols, fluorinated hydrocarbon compounds Any of 1,3,5-trioxane (alias: trioxane), camphor (alias: kamfer, camphor), naphthalene, iodine, and cyclohexane may be other substances.

The solvent can be selected from pure water, IPA, HFE (hydrofluoroether), acetone, PGMEA (propylene glycol monomethyl ether acetate), PGEE (propylene glycol monoethyl ether, 1-ethoxy-2-propanol), ethyl acetate, for example. At least one of the group consisting of glycol and hydrofluorocarbon.

Hereinafter, an example in which the sublimable substance is camphor and the solvent is any of IPA, acetone, and PGEE will be described. The vapor pressure of IPA is higher than that of camphor. Similarly, the vapor pressure of acetone and PGEE is higher than that of camphor. The vapor pressure of acetone is higher than that of IPA, and the vapor pressure of IPA is higher than that of PGEE. The freezing point of camphor (freezing point at 1 atmosphere, the same below) is 175~177℃. No matter which the solvent is IPA, acetone, or PGEE, the freezing point of camphor is higher than the boiling point of the solvent. The freezing point of camphor is higher than the freezing point of the treatment solution before drying. The freezing point of the treatment solution before drying is lower than room temperature (23°C or its vicinity). The substrate processing apparatus 1 is arranged in a clean room maintained at room temperature. Therefore, even if the pre-treatment liquid is not heated and dried, the pre-drying treatment liquid can be maintained as a liquid. The freezing point of the treatment solution before drying can also be above room temperature.

As described below, the replacement liquid is supplied to the upper surface of the substrate W covered by the liquid film of the rinse liquid, and the pre-drying treatment liquid is supplied to the upper surface of the substrate W covered by the liquid film of the replacement liquid. The replacement liquid is a liquid that dissolves with the rinse liquid and the pre-drying treatment liquid. The replacement fluid is, for example, IPA or HFE. The replacement liquid may be a mixed liquid of IPA and HFE, or may contain at least one of IPA and HFE and other components. IPA and HFE are liquids that dissolve with water and fluorinated hydrocarbon compounds.

When the replacement liquid is supplied to the upper surface of the substrate W covered by the liquid film of the rinse liquid, most of the rinse liquid on the substrate W is washed away by the replacement liquid and discharged from the substrate W. The remaining trace amount of rinsing fluid is dissolved in the replacement fluid and diffused in the replacement fluid. The diffused rinsing liquid is discharged from the substrate W together with the replacement liquid. Therefore, the rinse liquid on the substrate W can be efficiently replaced with the replacement liquid. For the same reason, the replacement liquid on the substrate W can be efficiently replaced with the pre-drying treatment liquid. Thereby, the rinse liquid contained in the pre-drying treatment liquid on the substrate W can be reduced.

The pre-drying treatment liquid nozzle 39 is connected to a nozzle moving unit 42 that moves the pre-drying treatment liquid nozzle 39 in at least one of a vertical direction and a horizontal direction. The nozzle moving unit 42 places the pre-drying treatment liquid nozzle 39 at the processing position where the pre-drying treatment liquid sprayed from the pre-drying treatment liquid nozzle 39 is supplied to the upper surface of the substrate W, and the pre-drying treatment liquid nozzle 39 is located in the treatment cup in a plan view. Move horizontally between the standby positions around 21.

Similarly, the replacement liquid nozzle 43 is connected to a nozzle moving unit 46 that moves the replacement liquid nozzle 43 in at least one of the vertical direction and the horizontal direction. The nozzle moving unit 46 makes the replacement liquid nozzle 43 perform between the processing position where the replacement liquid sprayed from the replacement liquid nozzle 43 is supplied to the upper surface of the substrate W and the standby position where the replacement liquid nozzle 43 is located around the processing cup 21 in a plan view. Move horizontally.

The processing unit 2 includes a blocking member 51 disposed above the rotating chuck 10. FIG. 2 shows an example in which the blocking member 51 is a disk-shaped blocking plate. The blocking member 51 includes a circular plate portion 52 horizontally arranged above the rotating chuck 10. The blocking member 51 is horizontally supported by a cylindrical support shaft 53 extending upward from the central portion of the circular plate portion 52. The center line of the circular plate portion 52 is arranged on the rotation axis A1 of the substrate W. The lower surface of the disc portion 52 corresponds to the lower surface 51L of the blocking member 51. The lower surface 51L of the blocking member 51 is an opposite surface facing the upper surface of the substrate W. The lower surface 51L of the blocking member 51 is parallel to the upper surface of the substrate W, and has an outer diameter greater than the diameter of the substrate W.

The blocking member 51 is connected to a blocking member elevating unit 54 that vertically raises and lowers the blocking member 51. The blocking member lifting unit 54 positions the blocking member 51 at any position from the upper position (the position shown in FIG. 2) to the lower position. The lower position is a close position where the lower surface 51L of the blocking member 51 approaches the upper surface of the substrate W until the scanning nozzles such as the chemical liquid nozzle 31 cannot enter the height between the substrate W and the blocking member 51. The upper position is a position where the blocking member 51 is retracted to a position where the scanning nozzle can enter the height between the blocking member 51 and the substrate W.

The plurality of nozzles includes a center nozzle 55 that sprays a processing fluid such as a processing liquid or a processing gas downward through a central opening 61 above the central opening of the lower surface 51L of the blocking member 51. The center nozzle 55 extends up and down along the rotation axis A1. The center nozzle 55 is arranged in a through hole that penetrates the center portion of the blocking member 51 up and down. The inner peripheral surface of the blocking member 51 surrounds the outer peripheral surface of the center nozzle 55 at intervals in the radial direction (the direction orthogonal to the rotation axis A1). The center nozzle 55 moves up and down together with the blocking member 51. The ejection port of the central nozzle 55 for ejecting the processing liquid is arranged above the central opening 61 of the blocking member 51.

The center nozzle 55 is connected to a gas piping 56 that guides the inert gas to the upper side of the center nozzle 55. The substrate processing apparatus 1 may include a temperature regulator 59 that heats or cools the inert gas ejected from the center nozzle 55. When the gas valve 57 installed on the upper gas pipe 56 is opened, the inert gas is continuously ejected downward from the ejection port of the center nozzle 55 at a flow rate corresponding to the opening of the flow rate adjustment valve 58 that changes the flow rate of the inert gas. The inert gas sprayed from the central nozzle 55 is nitrogen. The inert gas may also be a gas other than nitrogen such as helium or argon.

The inner peripheral surface of the blocking member 51 and the outer peripheral surface of the center nozzle 55 form a cylindrical upper gas flow path 62 extending up and down. The upper gas flow path 62 is connected to a gas piping 63 that introduces inert gas into the upper central opening 61 of the blocking member 51. The substrate processing apparatus 1 may include an upper temperature regulator 66 for heating or cooling the inert gas sprayed from the central opening 61 on the blocking member 51. When the gas valve 64 installed on the upper gas pipe 63 is opened, the inert gas is continuously ejected downward from the upper central opening 61 of the blocking member 51 at a flow rate corresponding to the opening of the flow rate adjusting valve 65 for changing the flow rate of the inert gas. gas. The inert gas sprayed from the central opening 61 on the blocking member 51 is nitrogen. The inert gas may also be a gas other than nitrogen such as helium or argon.

The plurality of nozzles includes a lower surface nozzle 71 that ejects the processing liquid to the center of the lower surface of the substrate W. The lower surface nozzle 71 includes a nozzle disc portion arranged between the upper surface 12u of the spin base 12 and the lower surface of the substrate W, and a nozzle cylindrical portion extending downward from the nozzle disc portion. The ejection port of the lower surface nozzle 71 opens at the center of the upper surface of the nozzle disc. When the substrate W is rotated in the chuck 10, the ejection port of the nozzle 71 on the lower surface faces the center of the lower surface of the substrate W vertically.

The lower surface nozzle 71 is connected to a heating fluid pipe 72 that guides warm water (pure water with a temperature higher than room temperature) as an example of the heating fluid to the lower surface nozzle 71. The pure water supplied to the lower surface nozzle 71 is heated by the heater 75 installed under the heating fluid pipe 72. When the heating fluid valve 73 installed in the heating fluid pipe 72 is opened, the warm water is continuously sprayed upward from the spray port of the lower surface nozzle 71 at a flow rate corresponding to the opening of the flow rate adjustment valve 74 that changes the flow rate of the warm water. Thereby, warm water is supplied to the lower surface of the substrate W.

The lower surface nozzle 71 is further connected to a cooling fluid pipe 76 that guides cold water (pure water with a temperature lower than room temperature) as an example of the cooling fluid to the lower surface nozzle 71. The pure water supplied to the lower surface nozzle 71 is cooled by the cooler 79 installed in the cooling fluid pipe 76. When the cooling fluid valve 77 installed in the cooling fluid pipe 76 is opened, the cooling water is continuously sprayed upward from the spray port of the lower surface nozzle 71 at a flow rate corresponding to the opening of the flow control valve 78 that changes the flow rate of the cooling water. Thereby, cold water is supplied to the lower surface of the substrate W.

The outer peripheral surface of the lower surface nozzle 71 and the inner peripheral surface of the rotating base 12 form a cylindrical lower gas flow path 82 extending up and down. The lower gas flow path 82 includes a central opening 81 below the central opening of the upper surface 12 u of the rotating base 12. The lower gas flow path 82 is connected to a gas pipe 83 that introduces inert gas into the lower central opening 81 under the rotating base 12. The substrate processing apparatus 1 may also include a lower temperature regulator 86 for heating or cooling the inert gas sprayed from the central opening 81 under the rotating susceptor 12. When the gas valve 84 installed under the lower gas piping 83 is opened, the inert gas is continuously ejected upward from the lower central opening 81 of the rotating base 12 at a flow rate corresponding to the opening of the flow rate adjustment valve 85 that changes the flow rate of the inert gas. gas.

The inert gas sprayed from the central opening 81 under the rotating base 12 is nitrogen. The inert gas may also be a gas other than nitrogen such as helium or argon. When the substrate W is held on the spin chuck 10, when nitrogen is ejected from the central opening 81 under the spin base 12, the nitrogen is radiated in all directions between the lower surface of the substrate W and the upper surface 12u of the spin base 12状流。 State flow. Thereby, the space between the substrate W and the spin base 12 is filled with nitrogen gas.

Next, the pre-drying treatment liquid supply unit will be described.

FIG. 3 is a schematic diagram showing a pre-drying treatment liquid supply unit included in the substrate processing apparatus 1.

The substrate processing apparatus 1 includes a pre-drying processing liquid supply unit that supplies a pre-drying processing liquid to a pre-drying processing liquid nozzle 39 through a pre-drying processing liquid pipe 40.

The pre-drying treatment liquid supply unit includes: a first tank 87A storing the pre-drying treatment liquid, a first circulation pipe 88A that circulates the pre-drying treatment liquid in the first tank 87A, and the drying pre-treatment liquid in the first tank 87A The first pump 89A that is sent to the first circulation pipe 88A, and the first separation pipe 90A that guides the pre-drying treatment liquid in the first circulation pipe 88A to the pre-drying treatment liquid pipe 40. The pre-drying treatment liquid supply unit further includes a first on-off valve 91A that opens and closes the inside of the first separation pipe 90A, and a first that changes the flow rate of the pre-drying treatment liquid supplied from the first separation pipe 90A to the pre-drying treatment liquid pipe 40. Flow adjustment valve 92A.

The pre-drying treatment liquid supply unit includes: a second tank 87B for storing the pre-drying treatment liquid, a second circulation pipe 88B for circulating the pre-drying treatment liquid in the second tank 87B, and the pre-drying treatment liquid in the second tank 87B The second pump 89B that is sent to the second circulation pipe 88B, and the second separation pipe 90B that guides the pre-drying treatment liquid in the second circulation pipe 88B to the pre-drying treatment liquid pipe 40. The pre-drying treatment liquid supply unit further includes a second on-off valve 91B that opens and closes the inside of the second separation pipe 90B, and a second that changes the flow rate of the pre-drying treatment liquid supplied from the second separation pipe 90B to the pre-drying treatment liquid pipe 40. Flow adjustment valve 92B.

The concentration of the pre-drying treatment liquid in the first tank 87A (the concentration of the sublimable substance contained in the pre-drying treatment liquid) is different from the concentration of the pre-drying treatment liquid in the second tank 87B. Therefore, when the first on-off valve 91A and the second on-off valve 91B are opened, the pre-drying treatment liquids with different concentrations are mixed with each other in the pre-drying treatment liquid piping 40, and sprayed from the pre-drying treatment liquid nozzle 39 for uniformly mixed drying Pre-treatment liquid. Furthermore, if the opening degree of at least one of the first flow control valve 92A and the second flow control valve 92B is changed, the concentration of the pre-drying treatment liquid sprayed from the pre-drying treatment liquid nozzle 39 is changed.

The control device 3 sets the opening degrees of the first on-off valve 91A, the second on-off valve 91B, the first flow rate regulating valve 92A, and the second flow rate regulating valve 92B based on the concentration of the pre-drying treatment liquid specified by the following process conditions. For example, when the concentration of the pre-drying treatment liquid specified by the process conditions matches the concentration of the pre-drying treatment liquid in the first tank 87A, the first on-off valve 91A is opened and the second on-off valve 91B is closed. When the concentration of the pre-drying solution specified by the process conditions is between the concentration of the pre-drying solution in the first tank 87A and the concentration of the pre-drying solution in the second tank 87B, open the first on-off valve Both 91A and the second on-off valve 91B adjust the opening degrees of the first flow rate adjustment valve 92A and the second flow rate adjustment valve 92B. Thereby, the concentration of the pre-drying treatment liquid sprayed from the pre-drying treatment liquid nozzle 39 is close to the concentration of the pre-drying treatment liquid specified by the process conditions.

FIG. 4 is a block diagram showing the hardware of the control device 3.

The control device 3 is a computer including a computer body 3a and a peripheral device 3b connected to the computer body 3a. The computer body 3a includes a CPU 93 (central processing unit) for executing various commands and a main memory device 94 for storing information. The peripheral device 3b includes an auxiliary memory device 95 for storing information such as the program P, a reading device 96 for reading information from the removable medium M, and a communication device 97 for communicating with other devices such as a host computer.

The control device 3 is connected to the input device 98 and the display device 99. The input device 98 is for an operator such as a user or a maintenance person to perform operations when inputting information to the substrate processing apparatus 1. The information is displayed on the screen of the display device 99. The input device 98 may be any one of a keyboard, a pointing device, and a touch panel, or may be other devices. A touch panel display that doubles as the input device 98 and the display device 99 may also be installed in the substrate processing apparatus 1.

The CPU 93 executes the program P stored in the auxiliary memory device 95. The program P in the auxiliary memory device 95 can be pre-installed in the control device 3, or can be transferred from the removable medium M to the auxiliary memory device 95 via the reading device 96, or from the host computer via the communication device 97 Wait for the external device to be transferred to the auxiliary memory device 95.

The auxiliary memory device 95 and the removable medium M are non-volatile memory that retains memory even if power is not supplied. The auxiliary memory device 95 is, for example, a magnetic memory device such as a hard disk drive. The removable medium M is, for example, an optical disc such as a compact disc or a semiconductor memory such as a memory card. The removable medium M is an example of a recording medium that can be read by a computer on which the program P is recorded. The removable medium M is a non-temporary tangible recording medium.

The auxiliary memory device 95 memorizes a plurality of process conditions. The process conditions are information that specifies the processing content, processing conditions, and processing sequence of the substrate W. Among the plurality of process conditions, at least one of the processing content, processing conditions, and processing sequence of the substrate W is different from each other. The control device 3 controls the substrate processing device 1 in a manner to process the substrate W according to the process conditions specified by the host computer. The following steps are executed by causing the control device 3 to control the substrate processing apparatus 1. In other words, the control device 3 is programmed to execute the following steps.

Next, an example of the processing of the substrate W in the first embodiment will be described.

The substrate W to be processed is, for example, a semiconductor wafer such as a silicon wafer. The surface of the substrate W is equivalent to the device forming surface for forming devices such as transistors or capacitors. The substrate W may be a substrate W on which the pattern P1 (see FIG. 6A) is formed on the surface of the substrate W as a pattern forming surface, or may be a substrate W on which the pattern P1 is not formed on the surface of the substrate W. In the latter case, the pattern P1 can be formed in the following chemical liquid supply step.

FIG. 5 is a step diagram for explaining an example of the processing of the substrate W in the first embodiment. 6A to 6C are schematic diagrams showing the state of the substrate W when the substrate W shown in FIG. 5 is processed.

Hereinafter, refer to FIG. 2 and FIG. 5. Refer to FIGS. 6A to 6C as appropriate.

When the substrate W is processed by the substrate processing apparatus 1, a carrying-in step of carrying the substrate W into the chamber 4 (step S1 in FIG. 5) is performed.

Specifically, when the blocking member 51 is in the upper position, all the protective covers 24 are in the lower position, and all the scanning nozzles are in the standby position, the center robot CR (refer to FIG. 1) supports the substrate W with the robot H1 while making The robot H1 enters the chamber 4. Then, the center robot CR places the substrate W on the robot H1 on the plurality of chuck pins 11 with the surface of the substrate W facing upward. After that, a plurality of chuck pins 11 are pressed against the outer peripheral surface of the substrate W, and the substrate W is held. After placing the substrate W on the rotating chuck 10, the center robot CR causes the robot hand H1 to withdraw from the inside of the chamber 4.

Then, the upper gas valve 64 and the lower gas valve 84 are opened, and the upper central opening 61 of the blocking member 51 and the lower central opening 81 of the rotating base 12 start to spray nitrogen gas. Thereby, the space between the substrate W and the blocking member 51 is filled with nitrogen gas. Similarly, the space between the substrate W and the spin base 12 is filled with nitrogen. On the other hand, the protective cover lifting unit 27 raises at least one protective cover 24 from the lower position to the upper position. After that, the rotation motor 14 is driven to start the rotation of the substrate W (step S2 in FIG. 5). Thereby, the substrate W rotates at the liquid supply speed.

Then, a chemical liquid supply step is performed to supply the chemical liquid to the upper surface of the substrate W to form a liquid film covering the entire upper surface of the substrate W (step S3 in FIG. 5).

Specifically, when the blocking member 51 is at the upper position and the at least one protective cover 24 is at the upper position, the nozzle moving unit 34 moves the liquid chemical nozzle 31 from the standby position to the processing position. After that, the chemical liquid valve 33 is opened, and the chemical liquid nozzle 31 starts to discharge the chemical liquid. When a certain time elapses after the liquid medicine valve 33 is opened, the liquid medicine valve 33 is closed to stop spraying the liquid medicine. After that, the nozzle moving unit 34 moves the chemical liquid nozzle 31 to the standby position.

After the chemical liquid ejected from the chemical liquid nozzle 31 collides with the upper surface of the substrate W rotating at the liquid supply speed, it flows outward along the upper surface of the substrate W by centrifugal force. Therefore, the chemical solution is supplied to the entire upper surface of the substrate W, and a liquid film of the chemical solution covering the entire upper surface of the substrate W is formed. When the chemical liquid nozzle 31 ejects the chemical liquid, the nozzle moving unit 34 can move the impingement position of the chemical liquid on the upper surface of the substrate W through the center and the outer periphery, or make the impingement position static in the center. Department.

Then, a rinsing liquid supply step of supplying pure water as an example of a rinsing liquid to the upper surface of the substrate W to rinse the chemical liquid on the substrate W is performed (step S4 in FIG. 5).

Specifically, in a state where the blocking member 51 is located at the upper position and at least one protective cover 24 is located at the upper position, the nozzle moving unit 38 moves the washing liquid nozzle 35 from the standby position to the processing position. After that, the flushing liquid valve 37 is opened, and the flushing liquid nozzle 35 starts to spray the flushing liquid. Before starting the spraying of pure water, the protective cover lifting unit 27 may also vertically move the at least one protective cover 24 to switch the protective cover 24 that receives the liquid discharged from the substrate W. When a certain time has elapsed after the flushing liquid valve 37 is opened, the flushing liquid valve 37 is closed to stop spraying the flushing liquid. After that, the nozzle moving unit 38 moves the rinse liquid nozzle 35 to the standby position.

After the pure water sprayed from the rinse liquid nozzle 35 collides with the upper surface of the substrate W rotating at the liquid supply speed, it flows outward along the upper surface of the substrate W by centrifugal force. The chemical liquid on the substrate W is replaced with pure water sprayed from the rinse liquid nozzle 35. Thereby, a liquid film of pure water covering the entire upper surface of the substrate W is formed. When the rinsing liquid nozzle 35 sprays pure water, the nozzle moving unit 38 can move the impingement position of the pure water on the upper surface of the substrate W through the center and the outer periphery, or make the impingement position stand still in the center. Department.

Then, a replacement liquid supply step is performed to supply the replacement liquid to the upper surface of the substrate W that dissolves with the rinse liquid and the pre-drying treatment liquid, and to replace the pure water on the substrate W with the replacement liquid (step S5 in FIG. 5) .

Specifically, in a state where the blocking member 51 is located at the upper position and at least one protective cover 24 is located at the upper position, the nozzle moving unit 46 moves the replacement liquid nozzle 43 from the standby position to the processing position. After that, the replacement liquid valve 45 is opened, and the replacement liquid nozzle 43 starts to discharge the replacement liquid. Before starting the spraying of the replacement liquid, the protective cover lifting unit 27 can also move the at least one protective cover 24 vertically to switch the protective cover 24 that receives the liquid discharged from the substrate W. When a certain time has elapsed after the replacement liquid valve 45 is opened, the replacement liquid valve 45 is closed and the discharge of the replacement liquid is stopped. After that, the nozzle moving unit 46 moves the replacement liquid nozzle 43 to the standby position.

After the replacement liquid ejected from the replacement liquid nozzle 43 collides with the upper surface of the substrate W rotating at the liquid supply speed, it flows outward along the upper surface of the substrate W by centrifugal force. The pure water on the substrate W is replaced with the replacement liquid sprayed from the replacement liquid nozzle 43. Thereby, a liquid film of the replacement liquid covering the entire upper surface of the substrate W is formed. When the replacement liquid nozzle 43 ejects the replacement liquid, the nozzle moving unit 46 can move the imposition position of the replacement liquid on the upper surface of the substrate W through the center and the outer periphery, or make the imposition position stand still at the center. Department. In addition, after forming a liquid film of the replacement liquid covering the entire upper surface of the substrate W, it is also possible to stop the replacement liquid nozzle 43 from spraying the replacement liquid, and to set the substrate W at a speed of the coating liquid (for example, a speed of less than 20 rpm and more than 0). ) Rotate.

Then, a pre-drying treatment liquid supply step of supplying the pre-drying treatment liquid to the upper surface of the substrate W to form a liquid film of the pre-drying treatment liquid on the substrate W (step S6 in FIG. 5) is performed.

Specifically, in a state where the blocking member 51 is at the upper position and at least one protective cover 24 is at the upper position, the nozzle moving unit 42 moves the pre-drying treatment liquid nozzle 39 from the standby position to the treatment position. Thereafter, the pre-drying treatment liquid valve 41 is opened, and the pre-drying treatment liquid nozzle 39 starts to spray the pre-drying treatment liquid. Before starting to spray the pre-drying treatment liquid, the protective cover lifting unit 27 can also move the at least one protective cover 24 vertically to switch the protective cover 24 that receives the liquid discharged from the substrate W. When a certain time has elapsed after the pre-drying treatment liquid valve 41 is opened, the pre-drying treatment liquid valve 41 is closed, and the spraying of the pre-drying treatment liquid is stopped. After that, the nozzle moving unit 42 moves the pre-drying treatment liquid nozzle 39 to the standby position.

After the pre-drying treatment liquid ejected from the pre-drying treatment liquid nozzle 39 collides with the upper surface of the substrate W rotating at the liquid supply speed, it flows outward along the upper surface of the substrate W by centrifugal force. The replacement liquid on the substrate W is replaced with the pre-drying treatment liquid ejected from the pre-drying treatment liquid nozzle 39. Thereby, a liquid film of the pre-drying treatment liquid covering the entire upper surface of the substrate W is formed. When the pre-drying treatment liquid nozzle 39 sprays the pre-drying treatment liquid, the nozzle moving unit 42 can move the imposition position of the drying pre-treatment liquid on the upper surface of the substrate W through the central part and the outer peripheral part. The landing position is stationary at the center.

Then, a part of the pre-drying treatment liquid on the substrate W is removed, while maintaining the state of covering the entire upper surface of the substrate W with a liquid film of the pre-drying treatment liquid, while reducing the film thickness of the pre-drying treatment liquid on the substrate W ( The film thickness reduction step of the thickness of the liquid film (step S7 in FIG. 5).

Specifically, in the state where the blocking member 51 is located at the lower position, the rotation motor 14 maintains the rotation speed of the substrate W at the film thickness reduction speed. The film thickness reduction speed may be the same as or different from the liquid supply speed. The pre-drying treatment liquid on the substrate W is also discharged from the substrate W to the outside by centrifugal force after the spraying of the pre-drying treatment liquid is stopped. Therefore, the thickness of the liquid film of the pre-drying treatment liquid on the substrate W is reduced. When the pre-drying treatment liquid on the substrate W has been discharged to a certain extent, the discharge amount of the pre-drying treatment liquid from the substrate W per unit time is reduced to zero or substantially zero. Thereby, the thickness of the liquid film of the pre-drying treatment liquid on the substrate W is stabilized to a value corresponding to the rotation speed of the substrate W.

Then, a solidified body forming step (step S8 of FIG. 5) is performed to solidify the pre-drying treatment liquid on the substrate W to form a solidified body 101 (refer to FIG. 6B) containing a sublimable substance on the substrate W.

Specifically, in a state where the blocking member 51 is in the lower position, the rotation motor 14 maintains the rotation speed of the substrate W at the solidified body formation speed. The solidified body formation speed may be the same as the liquid supply speed or different from the liquid supply speed. Furthermore, the upper gas valve 57 is opened, and the center nozzle 55 starts to spray nitrogen gas. It is also possible to open the upper gas valve 57 and change the opening degree of the flow regulating valve 65, or change the opening degree of the flow regulating valve 65 instead of opening the upper gas valve 57 to increase the flow rate of nitrogen gas sprayed from the central opening 61 on the blocking member 51 .

When the rotation of the substrate W starts at the solidified body formation speed, the evaporation of the pre-drying treatment liquid is promoted, and a part of the pre-drying treatment liquid on the substrate W evaporates. Since the vapor pressure of the solvent is higher than the vapor pressure of the sublimable substance equivalent to the solute, the solvent evaporates at an evaporation rate faster than the evaporation rate of the sublimable substance. As a result, the concentration of sublimable substances gradually increases, while the film thickness of the treatment solution before drying gradually decreases. The freezing point of the treatment solution before drying rises as the concentration of the sublimable substance increases. 6A and 6B, it can be seen that when the freezing point of the pre-drying treatment liquid reaches the temperature of the pre-drying treatment liquid, the pre-drying treatment liquid begins to solidify, forming a solidified body 101 equivalent to a cured film covering the entire upper surface of the substrate W.

Then, a sublimation step of sublimating the solidified body 101 on the substrate W and removing it from the upper surface of the substrate W is performed (step S9 in FIG. 5).

Specifically, in the state where the blocking member 51 is located at the lower position, the rotation motor 14 maintains the rotation speed of the substrate W at the sublimation speed. The sublimation speed may be the same as or different from the liquid supply speed. Furthermore, when the upper gas valve 57 is closed, the upper gas valve 57 is opened, and the center nozzle 55 starts to spray nitrogen gas. Open the upper gas valve 57 and change the opening degree of the flow regulating valve 65, or change the opening degree of the flow regulating valve 65 instead of opening the upper gas valve 57 to increase the flow rate of nitrogen gas sprayed from the central opening 61 on the blocking member 51. When the rotation of the substrate W at the sublimation speed starts for a certain period of time, the rotation motor 14 is stopped, and the rotation of the substrate W is stopped (step S10 in FIG. 5).

When the rotation of the substrate W is started at the sublimation speed, the solidified body 101 on the substrate W starts to sublimate, and the solidified body 101 on the substrate W generates gas containing sublimable substances. The gas generated from the solidified body 101 (gas containing sublimable substances) flows radially in the space between the substrate W and the blocking member 51 and is discharged from above the substrate W. And, when a certain amount of time has passed after the start of sublimation, as shown in FIG. 6C, all the solidified bodies 101 are removed from the substrate W.

Then, the unloading step of unloading the substrate W from the chamber 4 is performed (step S11 in FIG. 5).

Specifically, the blocking member raising and lowering unit 54 raises the blocking member 51 to the upper position, and the shield raising and lowering unit 27 lowers all the shields 24 to the lower position. Furthermore, the upper gas valve 64 and the lower gas valve 84 are closed, so that the upper central opening 61 of the blocking member 51 and the lower central opening 81 of the rotating base 12 stop spraying nitrogen gas. After that, the central robot CR makes the robot hand H1 enter the chamber 4. The center robot CR supports the substrate W on the rotating chuck 10 with the robot H1 after releasing the holding of the substrate W by the plurality of chuck pins 11. After that, the center robot CR supports the substrate W with the robot H1 while retreating the robot H1 from the inside of the chamber 4. Thereby, the processed substrate W is carried out from the chamber 4.

FIG. 7 is a graph showing an example of the concept that the thickness of the liquid film of the pre-drying treatment liquid on the substrate W decreases due to the evaporation of the solvent.

In Figure 7, the solid line represents the thickness of the liquid film when the initial concentration of the sublimable substance is the reference concentration, and the single-dot chain line represents the thickness of the liquid film when the initial concentration of the sublimable substance is low. The chain line represents the thickness of the liquid film when the initial concentration of the sublimable substance is high. The reference concentration is higher than the low concentration and lower than the high concentration. The initial concentration of the sublimable substance means the concentration of the sublimable substance in the pre-drying treatment solution supplied to the substrate W.

If the concentration of the sublimable substance in the pre-drying treatment liquid is the same, the thickness T1 of the solidified body 101 formed on the substrate W (see FIG. 6B) depends on the film thickness of the pre-drying treatment liquid before the solidified body 101 is formed (liquid film The thickness). That is, if the film thickness of the pre-drying treatment liquid is large, a thicker solidified body 101 is formed, and if the film thickness of the pre-drying treatment liquid is small, a thinner solidified body 101 is formed. Therefore, by changing the film thickness of the treatment liquid before drying, the thickness T1 of the solidified body 101 can be changed.

If the rotation speed of the substrate W is increased, the pre-drying treatment liquid is discharged from the substrate W due to centrifugal force, and the film thickness of the pre-drying treatment liquid on the substrate W is reduced. At this time, if the gas is sprayed toward the upper surface of the substrate W, the pressure of the gas is applied to the pre-drying treatment liquid, and the film thickness of the pre-drying treatment liquid on the substrate W is further reduced. However, if the film thickness is reduced to a certain extent, the flow velocity in the liquid film is extremely reduced, so even if the rotation speed or the gas flow rate is increased, the film thickness does not change significantly. Conversely, if the rotation speed or the gas flow rate is excessively increased, the upper surface of the substrate W will be partially exposed from the liquid film.

Therefore, even if the rotation speed of the substrate W or the gas flow rate is changed, the film thickness of the pre-drying treatment solution before the formation of the solidified body 101 cannot be made extremely thin, and the extremely thin solidified body 101 cannot be formed. Therefore, an extremely thin solidified body 101 covering the entire upper surface of the substrate W (for example, a solidified body 101 having a thickness of more than 0 to 1 μm or less), or in an extremely thin range (for example, a range of more than 0 to 1 μm or less) is formed When the thickness T1 of the solidified body 101 is changed internally, the initial concentration of the sublimable substance must be changed.

In FIG. 7, the film thickness of the pre-drying treatment solution before the evaporation of the solvent is kept constant regardless of the initial concentration of the sublimable substance. In addition, as shown in FIG. 7, if the temperature of the treatment liquid before drying is equal, the concentration of the sublimable substance at the time when the precipitation of the solidified body 101 starts is kept constant regardless of the initial concentration of the sublimable substance. When the solvent is evaporated in order to form the solidified body 101, the concentration of the sublimable substance gradually increases, and the film thickness of the treatment solution before drying gradually decreases. The freezing point of the treatment solution before drying rises as the concentration of the sublimable substance increases. When the freezing point of the pre-drying treatment liquid reaches the temperature of the pre-drying treatment liquid, the pre-drying treatment liquid starts to solidify, and a solidified body 101 is formed on the substrate W.

As shown in FIG. 7, when the initial concentration of the sublimable substance is the reference concentration, the solidified body 101 with the reference thickness Tr is formed. When the initial concentration of the sublimable substance is low, the amount of the sublimable substance contained in the treatment solution before drying is small, so that the solidified body 101 thinner than the reference thickness Tr is formed. When the initial concentration of the sublimable substance is a high concentration, the amount of the sublimable substance contained in the treatment solution before drying is large, so that a solidified body 101 thicker than the reference thickness Tr is formed. Therefore, by controlling the initial concentration of the sublimable substance, the thickness T1 of the solidified body 101 can be changed in an extremely thin range.

FIG. 8 is a graph showing an example of the relationship between the initial concentration of the sublimable substance and the thickness T1 of the solidified body 101. The vol% in Figure 8 represents the volume percentage concentration. When the treatment liquid before drying changes to the solidified body 101, the color of the substance on the substrate W changes from transparent to opaque. If the opaque solidified body 101 is formed when the film thickness of the transparent pre-drying treatment liquid is measured by the spectroscopic interferometry, the measured value will change. The value immediately before the change is shown in FIG. 8 as the thickness T1 of the solidified body 101.

In Figure 8, when the initial concentration of the sublimable substance is 0.5 vol%, the thickness T1 of the solidified body 101 is about 100 μm, and when the initial concentration of the sublimable substance is 1.23 vol%, the thickness T1 of the solidified body 101 is 200 About μm. The initial concentration of the sublimable substance is roughly proportional to the thickness T1 of the solidified body 101. If the initial concentration of the sublimable substance increases, the thickness T1 of the solidified body 101 increases at a fixed ratio. Therefore, if the initial concentration of the sublimable substance is changed, the thickness T1 of the solidified body 101 can be changed in an extremely thin range.

FIG. 9 is a table showing an example of the embedding rate and the collapse rate of the pattern P1 obtained when a plurality of samples formed with the pattern P1 of the same shape and strength are processed while changing the initial concentration of camphor. Fig. 10 is a broken line chart showing the relationship between the concentration of camphor in Fig. 9 and the collapse rate of the pattern P1.

Figures 9 and 10 show the collapse rate of pattern P1 when the sublimable substance is camphor and the solvent is IPA. In the measurement conditions 1-1 to 1-13 shown in Figs. 9 and 10, the conditions other than the initial concentration of camphor are the same. The wt% in Figure 9 represents the mass percentage concentration. This is the same in other drawings such as FIG. 14.

The collapse rate of the pattern P1 is a value obtained by multiplying the ratio of the number of the collapsed patterns P1 to the total number of the patterns P1 by a factor of 100. The embedding rate is a value obtained by multiplying the ratio of the thickness T1 (refer to FIG. 6B) of the solidified body 101 to the height Hp (refer to FIG. 6B) of the pattern P1 (refer to FIG. 6B) by a factor of 100. That is, the embedding rate is calculated by the calculation formula of ((thickness T1 of solidified body 101 / height Hp of pattern P1)×100).

As shown in the measurement condition 1-1 of Fig. 9, when the initial concentration of camphor is 0.52 wt%, the collapse rate of the pattern P1 is 83.5%.

As shown in the measurement conditions 1-2 of Fig. 9, when the initial concentration of camphor is 0.62 wt%, the collapse rate of the pattern P1 is 83.1%.

As shown in the measurement conditions 1-3 of FIG. 9, when the initial concentration of camphor is 0.69 wt%, the collapse rate of the pattern P1 is 76.2%.

As shown in the measurement conditions 1-4 in Fig. 9, when the initial concentration of camphor is 0.78 wt%, the collapse rate of the pattern P1 is 36.1%.

As shown in the measurement conditions 1-13 of Fig. 9, when the initial concentration of camphor is 7.76 wt%, the collapse rate of the pattern P1 is 91.0%.

As shown in the measurement conditions 1-12 of Fig. 9, when the initial concentration of camphor is 4.03 wt%, the collapse rate of the pattern P1 is 91.7%.

As shown in the measurement conditions 1-11 of Fig. 9, when the initial concentration of camphor is 2.06 wt%, the collapse rate of the pattern P1 is 87.0%.

As shown in the measurement conditions 1-10 of Fig. 9, when the initial concentration of camphor is 1.55 wt%, the collapse rate of the pattern P1 is 46.8%.

Observing Figure 9 and Figure 10, it can be seen that when the initial concentration of camphor increases from 0.62 wt% to 0.69 wt%, the collapse rate of the pattern P1 decreases (measurement condition 1-2→measurement condition 1-3). In addition, when the initial concentration of camphor increased from 0.69 wt% to 0.78 wt%, the collapse rate of the pattern P1 drastically decreased (measurement conditions 1-3→measurement conditions 1-4).

On the other hand, when the initial concentration of camphor was reduced from 2.06 wt% to 1.55 wt%, the collapse rate of pattern P1 drastically decreased (measurement condition 1-11→measurement condition 1-10).

Therefore, the initial concentration of camphor is preferably more than 0.62 wt% and less than 2.06 wt%, and more preferably more than 0.78 wt% and less than 2.06 wt%.

When the initial concentration of camphor exceeds 0.62 wt% and does not reach 2.06 wt%, the collapse rate of pattern P1 does not reach 87.0%.

When the initial concentration of camphor is within the range of 0.78 wt% or more and 1.55 wt% or less, the collapse rate of the pattern P1 is 46.8% or less.

When the initial concentration of camphor is 0.89 wt% or more and 1.24 wt% or less, the collapse rate of the pattern P1 is 17.6% or less. The collapse rate of pattern P1 is the lowest when the initial concentration of camphor is 0.89 wt%, which is 8.32%.

Therefore, the initial concentration of camphor can be from 0.78 wt% to 1.55 wt%, or from 0.89 wt% to 1.24 wt%.

FIG. 11 is a broken line chart showing the relationship between the embedding rate and the collapse rate of the pattern P1 in FIG. 9.

As shown in the measurement condition 1-1 of Fig. 9, when the embedding rate is 65%, the collapse rate of the pattern P1 is 83.5%.

As shown in the measurement conditions 1-2 in Fig. 9, when the embedding rate is 76%, the collapse rate of the pattern P1 is 83.1%.

As shown in the measurement conditions 1-3 of Fig. 9, when the embedding rate is 83%, the collapse rate of the pattern P1 is 76.2%.

As shown in the measurement conditions 1-4 in Fig. 9, when the embedding rate is 91%, the collapse rate of the pattern P1 is 36.1%.

As shown in the measurement conditions 1-13 of Fig. 9, when the embedding rate is 797%, the collapse rate of the pattern P1 is 91.0%.

As shown in the measurement conditions 1-12 of Fig. 9, when the embedding rate is 418%, the collapse rate of the pattern P1 is 91.7%.

As shown in the measurement conditions 1-11 of Fig. 9, when the embedding rate is 219%, the collapse rate of the pattern P1 is 87.0%.

As shown in the measurement conditions 1-10 of Fig. 9, when the embedding rate is 168%, the collapse rate of the pattern P1 is 46.8%.

Observing Figure 9 and Figure 11, it can be seen that when the embedding rate increases from 76% to 83%, the collapse rate of the pattern P1 decreases (measurement condition 1-2→measurement condition 1-3). In addition, when the embedding rate increased from 83% to 91%, the collapse rate of the pattern P1 drastically decreased (measurement condition 1-3→measurement condition 1-4).

On the other hand, when the embedding rate is reduced from 219% to 168%, the collapse rate of the pattern P1 drastically decreases (measurement condition 1-11→measurement condition 1-10).

Therefore, the embedding rate is preferably more than 76% and less than 219%, and more preferably more than 83% and less than 219%.

When the embedding rate exceeds 76% and does not reach 219%, the collapse rate of pattern P1 does not reach 87.0%.

Within the range of the embedding rate from 91% to 168%, the collapse rate of the pattern P1 is 46.8% or less.

Within the range of the embedding rate from 102% to 138%, the collapse rate of pattern P1 is 17.6% or less. The collapse rate of pattern P1 is the lowest when the embedding rate is 102%, which is 8.32%.

Therefore, the embedding rate can be between 91% and 168%, or between 102% and 138%.

As mentioned above, the initial concentration of camphor is preferably more than 0.62 wt% and less than 2.06 wt%. As shown in Figure 9, when the initial concentration of camphor is 0.62 wt%, the embedding rate is 76%. When the initial concentration of camphor is 2.06 wt%, the embedding rate is 219%. Therefore, in this example, if the initial concentration of camphor is set to a value within a better range, the embedding rate is automatically set to a value within the better range.

12A and FIG. 12B are schematic diagrams for explaining the mechanism assumed for the phenomenon that the collapse rate of the pattern P1 becomes higher when the solidified body 101 is too thick. 13A and FIG. 13B are schematic diagrams for explaining the mechanism assumed for the phenomenon that the collapse rate of the pattern P1 becomes higher when the solidified body 101 is too thin.

As shown in FIG. 11, when the solidified body 101 is too thick (when the embedding rate is too high), the collapse rate of the pattern P1 becomes higher. Moreover, even though the thickness T1 of the solidified body 101 is smaller than the height Hp of the pattern P1, the collapse rate of the pattern P1 may be low, but when the solidified body 101 is too thin (when the embedding rate is too low), the pattern P1 collapses The rate becomes higher. In the following, the mechanism envisaged for these phenomena will be explained.

First, the mechanism assuming that the collapse rate of the pattern P1 increases when the solidified body 101 is too thick will be explained.

When the IPA contained in the treatment solution before drying evaporates, the concentration of camphor in the treatment solution before drying gradually increases, and the freezing point of the treatment solution before drying gradually rises. When the freezing point of the pre-drying treatment liquid reaches the temperature of the pre-drying treatment liquid, the pre-drying treatment liquid starts to solidify, and a solidified body 101 containing camphor is formed on the substrate W.

When the embedding rate is 100% or more, that is, when the thickness T1 of the solidified body 101 (refer to FIG. 6B) is greater than the height Hp of the pattern P1 (refer to FIG. 6B), it is not only in the pattern P1 before the solidified body 101 is formed. In between, and above the pattern P1, there is also a pre-drying treatment liquid. In a substrate W such as a semiconductor wafer, the interval between two adjacent convex patterns P1 is narrow, so the freezing point of the pre-drying treatment solution located between the patterns P1 is lowered. Therefore, the freezing point of the pre-drying treatment solution located between the patterns P1 is lower than the freezing point of the pre-drying treatment solution located above the patterns P1.

If the freezing point of the pre-drying treatment solution located above the pattern P1 is higher than the freezing point of the pre-drying treatment solution located between the patterns P1, the solidification of the pre-drying treatment solution will start at a position other than between the patterns P1. Specifically, as shown in FIG. 12A, the crystalline nucleus of camphor is generated on the surface layer of the pre-drying treatment liquid, that is, the liquid layer ranging from the upper surface (liquid surface) of the pre-drying treatment liquid to the upper surface of the pattern P1, and The crystal nucleus gradually becomes larger. In addition, when a certain amount of time elapses, the entire surface layer of the treatment liquid before drying is solidified and becomes a solidified body 101.

Here, if the freezing point of the pre-drying treatment solution located between the patterns P1 is lower than the freezing point of the pre-drying treatment solution located above the pattern P1, as shown in FIG. 12B, there is a pre-drying treatment solution located between the patterns P1. When it solidifies and remains in a liquid state. In this case, an interface between the solid (solidified body 101) and the liquid (treatment liquid before drying) is formed in the vicinity of the pattern P1. Fig. 12B shows the state where the unclear interface between the solid and the liquid is located between the pattern P1.

The surface free energy of solid and liquid are different from each other. When the unclear interface between the solid (solidified body 101) and the liquid (pre-drying treatment liquid) is located between the pattern P1, the force due to the Laplace pressure is applied to the pattern P1. At this time, the force applied to the pattern P1 increases as the solidified body 101 becomes thicker. Therefore, if the solidified body 101 is too thick, the collapse force that causes the pattern P1 to collapse exceeds the strength of the pattern P1, and the collapse rate of the pattern P1 becomes higher. It is considered that the collapse rate of the pattern P1 increases according to this mechanism.

Next, the mechanism of the hypothetical phenomenon that the collapse rate of the pattern P1 decreases even if the embedding rate does not reach 100% will be explained.

When the solidified body 101 is formed, as the IPA continues to evaporate, the upper surface (liquid surface) of the treatment liquid before drying gradually approaches the lower end of the pattern P1. When the thickness T1 of the solidified body 101 is significantly smaller than the height Hp of the pattern P1, as shown in FIG. 13A, the upper surface of the pre-drying treatment liquid moves to the two adjacent convex patterns P1 before the entire pre-drying treatment liquid is solidified between. That is, the interface between the gas and the liquid (treatment liquid before drying) moves between the patterns P1. Therefore, it is considered that the force generated by the surface tension of the treatment liquid before drying is applied to the pattern P1, and the pattern P1 collapses. In addition, it is considered that the solidified body 101 is formed in a state where the pattern P1 is collapsed as shown in FIG. 13B.

It is considered that when the thickness T1 of the solidified body 101 is slightly smaller than the height Hp of the pattern P1, the interface between the gas and the liquid may also move between the patterns P1. However, it is believed that in this case, a crystalline nucleus of camphor has been formed between the patterns P1, and the crystalline nucleus has become larger to a certain extent. In this case, the inclination of the pattern P1 is restricted by the larger crystal nucleus, and the collapse of the pattern P1 is not easy to occur. It is believed that according to this mechanism, even if the thickness T1 of the solidified body 101 is slightly smaller than the height Hp of the pattern P1, the collapse rate of the pattern P1 will decrease.

As described above, if the solidified body 101 is too thick or too thin, the collapse rate of the pattern P1 will decrease. In other words, in terms of reducing the collapse rate of the pattern P1 of the substrate W after drying, the thickness of the solidified body 101 has an appropriate range. For example, if the solidified body 101 is set to a value within the range described with reference to FIG. 9, the collapse rate of the pattern P1 of the substrate W after drying can be reduced. Thereby, the substrate W can be dried while suppressing the collapse rate of the pattern P1.

Next, the measurement result when another sample is used is explained.

Figures 14 to 16 are tables showing an example of the collapse rate of the pattern P1 obtained when a plurality of samples formed with the pattern P1 of the same shape and strength are processed while changing the initial concentration of camphor.

Figure 14 shows the collapse rate of the pattern P1 when the sublimable substance is camphor and the solvent is IPA. Figure 15 shows the collapse rate of the pattern P1 when the sublimable substance is camphor and the solvent is acetone. Figure 16 shows the collapse rate of the pattern P1 when the sublimable substance is camphor and solvent. It is the collapse rate of pattern P1 when it is PGEE.

In the measurement conditions 2-1 to 2-5 shown in Fig. 14, the conditions other than the initial concentration of camphor are the same. Similarly, in the measurement condition 3-1 to the measurement condition 3-13 shown in FIG. 15, the conditions other than the initial concentration of camphor are the same, and in the measurement condition 4-1 to the measurement condition 4-8 shown in FIG. 16, The conditions other than the initial concentration of camphor are the same.

In the measurement shown in Figure 14 to Figure 16, the same sample was used. The intensity of the pattern P1 of the sample used in the measurement of FIG. 14 to FIG. 16 is different from the intensity of the pattern P1 of the sample used in the measurement of FIG. 9. Therefore, although Figure 9 and Figure 14 both show the collapse rate of the pattern P1 when the sublimable substance is camphor and the solvent is IPA, the strength of the pattern P1 used in the measurement is different, so it is impossible to simply compare the figures in Figure 9 and Figure 14. Show the collapse rate.

FIG. 17 is a broken line chart showing the relationship between the concentration of camphor in FIG. 14 and the collapse rate of the pattern P1. FIG. 18 is a broken line chart showing the relationship between the concentration of camphor in FIG. 15 and the collapse rate of the pattern P1. FIG. 19 is a broken line chart showing the relationship between the concentration of camphor in FIG. 16 and the collapse rate of the pattern P1.

First, referring to FIGS. 14 and 17, an example of the relationship between the initial concentration of camphor and the collapse rate of the pattern P1 when the solvent is IPA will be described.

As shown in the measurement condition 2-1 of Fig. 14, when the initial concentration of camphor is 0.89 wt%, the collapse rate of the pattern P1 is 91.7%.

As shown in the measurement condition 2-2 of Figure 14, when the initial concentration of camphor is 0.96 wt%, the collapse rate of the pattern P1 is 58.4%.

As shown in the measurement conditions 2-3 in Figure 14, when the initial concentration of camphor is 1.13 wt%, the collapse rate of the pattern P1 is 37.3.

As shown in the measurement conditions 2-4 in Figure 14, when the initial concentration of camphor is 1.38 wt%, the collapse rate of the pattern P1 is 50.6%.

As shown in the measurement conditions 2-5 of Figure 14, when the initial concentration of camphor is 1.55 wt%, the collapse rate of the pattern P1 is 95.3%.

Observing Figures 14 and 17, it can be seen that when the initial concentration of camphor increases from 0.89 wt% to 0.96 wt%, the collapse rate of the pattern P1 decreases sharply (measurement condition 2-1→measurement condition 2-2). When the initial concentration of camphor was reduced from 1.55 wt% to 1.38 wt%, the collapse rate of pattern P1 also sharply decreased (measurement conditions 2-5→measurement conditions 2-4).

When the initial concentration of camphor is 0.96 wt% or more and 1.38 wt% or less, the collapse rate of the pattern P1 is 58.4% or less. Therefore, when the solvent is IPA, the initial concentration of camphor is preferably more than 0.89 wt% and less than 1.55 wt%, and more preferably 0.96 wt% or more and 1.38 wt% or less.

Next, referring to FIGS. 15 and 18, an example of the relationship between the initial concentration of camphor and the collapse rate of the pattern P1 when the solvent is acetone will be described.

As shown in the measurement condition 3-3 of Figure 15, when the initial concentration of camphor is 0.62 wt%, the collapse rate of the pattern P1 is 86.6%.

As shown in the measurement conditions 3-4 in Figure 15, when the initial concentration of camphor is 0.69 wt%, the collapse rate of the pattern P1 is 60.2%.

As shown in the measurement conditions 3-9 in Figure 15, when the initial concentration of camphor is 1.04 wt%, the collapse rate of the pattern P1 is 99.7%.

As shown in the measurement conditions 3-8 of Figure 15, when the initial concentration of camphor is 0.96 wt%, the collapse rate of the pattern P1 is 82.2%.

As shown in the measurement conditions 3-7 of Figure 15, when the initial concentration of camphor is 0.89 wt%, the collapse rate of the pattern P1 is 76.4%.

Observing Figure 15 and Figure 18, it can be seen that when the initial concentration of camphor increases from 0.62 wt% to 0.69 wt%, the collapse rate of pattern P1 decreases sharply (measurement condition 3-3→measurement condition 3-4). When the initial concentration of camphor was reduced from 1.04 wt% to 0.96 wt%, the collapse rate of pattern P1 also sharply decreased (measurement conditions 3-9→measurement conditions 3-8).

However, when the initial concentration of camphor is within the range of 0.96 wt% or more and 1.04 wt% or less, the collapse rate of the pattern P1 is not too low. When the initial concentration of camphor was reduced from 0.96 wt% to 0.89 wt% (measurement condition 3-8→measurement condition 3-7), the collapse rate of pattern P1 decreased sharply, and the collapse rate of pattern P1 was relatively low. Therefore, when the solvent is acetone, the initial concentration of camphor is preferably more than 0.62 wt% and less than 0.96 wt%.

Next, referring to FIGS. 16 and 19, an example of the relationship between the initial concentration of camphor and the collapse rate of the pattern P1 when the solvent is PGEE will be described.

As shown in the measurement condition 4-3 of Figure 16, when the initial concentration of camphor is 3.06 wt%, the collapse rate of the pattern P1 is 98.9%.

As shown in the measurement conditions 4-4 of Figure 16, when the initial concentration of camphor is 3.55 wt%, the collapse rate of the pattern P1 is 88.3%.

As shown in the measurement conditions 4-5 in Figure 16, when the initial concentration of camphor is 4.23 wt%, the collapse rate of the pattern P1 is 79.4%.

As shown in the measurement conditions 4-8 of Figure 16, when the initial concentration of camphor is 9.95 wt%, the collapse rate of the pattern P1 is 99.5%.

As shown in the measurement conditions 4-7 of Figure 16, when the initial concentration of camphor is 6.86 wt%, the collapse rate of the pattern P1 is 62.1%.

As shown in the measurement conditions 4-6 of Figure 16, when the initial concentration of camphor is 5.23 wt%, the collapse rate of the pattern P1 is 57.5%.

Observing Figure 15 and Figure 18, we can see that when the initial concentration of camphor increases from 3.06 wt% to 3.55 wt% (measurement condition 4-3→measurement condition 4-4), the collapse rate of pattern P1 decreases sharply, but within this range The collapse rate of the pattern P1 is not too low. When the initial concentration of camphor increased from 3.55 wt% to 4.23 wt% (measurement condition 4-4→measurement condition 4-5), the collapse rate of pattern P1 decreased sharply, and the collapse rate of pattern P1 was relatively low.

In addition, when the initial concentration of camphor was reduced from 9.95 wt% to 6.86 wt% (measurement condition 4-8→measurement condition 4-7), the collapse rate of pattern P1 decreased sharply, but the collapse rate of pattern P1 was included in this range The situation is not too low. That is, when the initial concentration of camphor is around 6.86 wt%, the collapse rate of the pattern P1 is low, but when the initial concentration of camphor is around 9.95 wt%, the collapse rate of the pattern P1 is relatively high.

When the initial concentration of camphor decreases from 6.86 wt% to 5.23 wt% (measurement condition 4-7→measurement condition 4-6), the collapse rate of pattern P1 gradually decreases. Therefore, when the solvent is PGEE, the initial concentration of camphor is preferably more than 3.55 wt% and less than 6.86 wt%.

Figure 20 is a chart formed by overlapping the broken lines of Figure 17 to Figure 19. In Fig. 20, the broken line (IPA) of Fig. 17 is represented by a solid line, the broken line (acetone) of Fig. 18 is represented by a broken line, and the broken line (PGEE) of Fig. 19 is represented by a single-dot chain line.

When the solvent is IPA, when the initial concentration of camphor is 1.13 wt%, the collapse rate of the pattern P1 is the lowest, which is 37.3% (measurement conditions 2-3).

When the solvent is acetone, when the initial concentration of camphor is 0.78 wt%, the collapse rate of pattern P1 is the lowest at 57.6% (measurement conditions 3-5).

When the solvent is PGEE, when the initial concentration of camphor is 5.23 wt%, the collapse rate of pattern P1 is the lowest at 57.5% (measurement conditions 4-6).

In other words, the initial concentration of camphor at the lowest collapse rate of the pattern P1 is 0.78 wt% when the solvent is acetone, 1.13 wt% when the solvent is IPA, and 5.23 wt% when the solvent is PGEE %. Focusing on the comparison of these solvents, it can be seen that the initial concentration of camphor at the lowest collapse rate of the pattern P1 increases as the vapor pressure of the solvent decreases. That is, if the solvent is easy to evaporate, it is not necessarily necessary to increase the concentration of the sublimable substance contained in the pre-drying treatment liquid. Conversely, if the solvent is difficult to evaporate, it is necessary to increase the concentration of the sublimable substance contained in the treatment liquid before drying.

In the present invention, it is necessary to form a solidified body 101 containing a sublimable substance on the surface of the substrate W by evaporating a solvent from the pre-drying treatment liquid. Therefore, for example, a step of selecting a solvent based on the vapor pressure of the sublimable substance may be performed.

As described above, according to the measurement result of FIG. 9, if the initial concentration of camphor is set to a value within a better range, the embedding rate is automatically set to a value within the better range. Therefore, it is considered that in the measurement of Figs. 14-16, if the initial concentration of camphor is set to a value within a better range, the embedding rate is automatically set to a value within a better range. It is considered that this reduces the collapse rate of the pattern P1.

However, it is considered that depending on the shape or intensity of the pattern P1, although the initial concentration of camphor is set to a value within a preferable range, the embedding rate may not necessarily be set to a value within a preferable range. Similarly, it is considered that depending on the shape or intensity of the pattern P1, although the embedding rate is set to a value within a preferable range, the initial concentration of camphor may not necessarily be set to a value within a preferable range.

As described above, in the first embodiment, the pre-drying treatment liquid containing the sublimable substance corresponding to the solute and the solvent is supplied to the surface of the substrate W on which the pattern P1 is formed. After that, the solvent was evaporated from the pre-drying treatment liquid. Thereby, a solidified body 101 containing a sublimable substance is formed on the surface of the substrate W. Thereafter, the solidified body 101 on the substrate W is changed into a gas without passing through the liquid. Thereby, the solidified body 101 is removed from the surface of the substrate W. Therefore, compared with previous drying methods such as spin drying, the collapse rate of the pattern P1 can be reduced.

When the solvent is evaporated from the pre-drying treatment liquid, a solidified body 101 containing a sublimable substance is formed on the surface of the substrate W. The embedding rate at the point of forming the solidified body 101 exceeded 76 and did not reach 219. As described above, when the embedding rate is outside this range, the number of collapses of the pattern P1 may increase depending on the strength of the pattern P1. Conversely, if the embedding rate is within this range, even if the strength of the pattern P1 is low, the number of collapses of the pattern P1 can be reduced. Therefore, even if the strength of the pattern P1 is low, the collapse rate of the pattern P1 can be reduced.

Next, the second embodiment will be described.

The main difference between the second embodiment and the first embodiment is that the pre-drying treatment liquid contains an adsorbent in addition to a sublimable substance and a solvent.

In the following FIGS. 21 to 23F, about the same configuration as the configuration shown in FIGS. 1 to 20, the same reference numerals as in FIG. 1 and the like are attached, and the description thereof is omitted.

FIG. 21 is a schematic view of the inside of the processing unit 2 included in the substrate processing apparatus 1 of the second embodiment when viewed horizontally.

The plurality of nozzles of the processing unit 2 further include a second chemical liquid nozzle 31B that ejects a different kind of chemical liquid from the chemical liquid nozzle 31 corresponding to the first chemical liquid nozzle to the upper surface of the substrate W. The second chemical liquid nozzle 31B may be a scanning nozzle that can move horizontally in the chamber 4 or a fixed nozzle that is fixed to the partition wall 5 of the chamber 4. FIG. 21 shows an example in which the second chemical liquid nozzle 31B is a scanning nozzle.

The second chemical liquid nozzle 31B is connected to a second chemical liquid pipe 32B that guides the chemical liquid to the second chemical liquid nozzle 31B. When the second chemical liquid valve 33B inserted in the second chemical liquid pipe 32B is opened, the chemical liquid is continuously ejected downward from the ejection port of the second chemical liquid nozzle 31B. If it is a different type of chemical liquid sprayed from the chemical liquid nozzle 31, the chemical liquid sprayed from the second chemical liquid nozzle 31B may include sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid, phosphoric acid, acetic acid, ammonia, and hydrogen peroxide. Liquids of at least one of water, organic acids (for example, citric acid, oxalic acid, etc.), organic bases (for example, TMAH: tetramethylammonium hydroxide, etc.), surfactants, and corrosion inhibitors, and other liquids may also be used.

The second chemical liquid nozzle 31B is connected to a nozzle moving unit 34B that moves the second chemical liquid nozzle 31B in at least one of the vertical direction and the horizontal direction. The nozzle moving unit 34B places the second chemical liquid nozzle 31B at the processing position where the chemical liquid ejected from the second chemical liquid nozzle 31B is supplied to the upper surface of the substrate W, and the second chemical liquid nozzle 31B is located between the processing cup 21 in a plan view. Move horizontally between the surrounding standby positions.

As described above, the pre-drying treatment liquid contains an adsorbent in addition to the sublimable substance and the solvent. The pre-drying treatment liquid is a solution containing a sublimable substance equivalent to the solute, a solvent that dissolves the sublimable substance, and an adsorbing substance adsorbed on the surface of the pattern P1 (refer to FIG. 23A). Sublimation substances, solvents, and adsorption substances are of different types. The adsorption substance is a substance that dissolves with at least one of the sublimation substance and the solvent.

The solvent is a liquid that dissolves a substance that dissolves each other with a sublimable substance. The concentration of dissolved substances in the treatment solution before drying is higher than the concentration of sublimable substances in the treatment solution before drying, and higher than the concentration of adsorbed substances in the treatment solution before drying. The concentration of the adsorbed substance in the treatment solution before drying can be equal to the concentration of the sublimation substance in the treatment solution before drying, or it can be different from the concentration of the sublimation substance in the treatment solution before drying.

The adsorbent is an amphiphilic molecule containing both a hydrophilic group and a hydrophobic group. The adsorbent can be a surfactant. If it is of a different type from the sublimable substance and solvent, the adsorbed substance may be a substance that changes from a solid to a gas without passing through a liquid under normal temperature or pressure (sublimable substance), or it may be a different substance. The sublimation substance can be a hydrophobic substance or a hydrophilic substance, or an amphiphilic molecule. Similarly, the solvent can be a hydrophobic substance or a hydrophilic substance, or an amphiphilic molecule.

When the sublimable substance is a hydrophilic substance or an amphiphilic molecule, the hydrophilicity of the adsorbed substance can be higher than that of the sublimable substance. In other words, the solubility of the adsorbent material with respect to water may be higher than the solubility of the sublimable material with respect to water. When the sublimation substance is a hydrophobic substance or an amphiphilic molecule, the hydrophobicity of the sublimation substance can be higher than that of the adsorption substance. In other words, the solubility of the sublimable substance with respect to oil may be higher than the solubility of the adsorbed substance with respect to oil. The same applies to solvents.

When the surface of the pattern P1 is hydrophilic, and the hydrophilicity of the adsorbed material is higher than that of the sublimable material, the adsorbed material is easier to adsorb on the surface of the pattern P1 than the sublimable material. The hydrophilic group of the adsorbing substance is attached to the surface of the pattern P1, and the sublimation substance is attached to the hydrophobic group of the adsorbing substance attached to the surface of the pattern P1. When the surface of the pattern P1 is hydrophobic and the hydrophobicity of the sublimable substance is higher than that of the adsorbed substance, the sublimable substance is more easily adsorbed on the surface of the pattern P1 than the adsorbed substance. Therefore, no matter whether the surface of the pattern P1 is hydrophilic or hydrophobic, the sublimable substance can be located on or near the surface of the pattern P1.

The freezing point of sublimable substances is higher than room temperature. The freezing point of the sublimable substance can be higher than the boiling point of the solvent. The freezing point of the solvent is lower than room temperature. The freezing point of the adsorbed substance can be room temperature or different from room temperature. When the freezing point of the adsorbed substance is higher than room temperature, the freezing point of the adsorbed substance can be equal to or different from the freezing point of the sublimable substance. The freezing point of the treatment solution before drying is lower than room temperature (23°C or its vicinity). The freezing point of the treatment solution before drying can also be above room temperature.

The vapor pressure of the solvent is higher than the vapor pressure of the sublimable substance and higher than the vapor pressure of the adsorbed substance. The vapor pressure of the adsorbed substance can be equal to or different from the vapor pressure of the sublimable substance. The solvent evaporates from the treatment solution before drying at an evaporation rate faster than the evaporation rate of the sublimation material and the adsorbing material. The freezing point of the treatment solution before drying rises as the solvent evaporates. When the freezing point of the treatment liquid before drying rises to room temperature, the treatment liquid before drying changes from a liquid to a solid. Thereby, a solidified body 101 containing a sublimable substance is formed.

Hereinafter, an example in which the sublimable substance is camphor, the solvent is IPA, and the adsorbent is tertiary butanol will be described. In the following description, the pre-drying treatment liquid is a solution of camphor, IPA, and tertiary butanol. You may include naphthalene instead of camphor in the pre-drying treatment liquid. It is also possible to include acetone or PGEE instead of IPA in the pre-drying treatment liquid. Cyclohexanol may be included in the pre-drying treatment liquid instead of tertiary butanol.

The molecule of camphor contains a hydrocarbyl group as a hydrophobic group and a carbonyl group as a hydrophilic group. The IPA molecule contains an alkyl group as a hydrophobic group and a hydroxyl group as a hydrophilic group. The molecule of tertiary butanol also contains an alkyl group as a hydrophobic group and a hydroxyl group as a hydrophilic group. IPA and tertiary butanol are amphiphilic molecules. Camphor is strictly an amphiphilic molecule, but its solubility with respect to water is much lower than that of tertiary butanol, so it is regarded as a hydrophobic substance. Camphor is more hydrophobic than tertiary butanol.

In the first tank 87A and the second tank 87B shown in FIG. 3, there are stored pre-drying treatment liquids with the same concentration of adsorbed substances and different concentrations of sublimable substances. Therefore, even if the pre-drying treatment liquid supplied from the first tank 87A is mixed with the pre-drying treatment liquid supplied from the second tank 87B, the concentration of the adsorbed substance in the mixed pre-drying treatment liquid will not be as high as that in the first tank 87A. And the concentration of the adsorbed substance in the pre-drying treatment liquid in the second tank 87B changes. The initial concentration of the sublimable substance in the drying pretreatment liquid in the first tank 87A and the second tank 87B can be set to the same value as in the first embodiment, or can be set to a value different from the first embodiment.

Next, an example of the processing of the substrate W in the second embodiment will be described.

FIG. 22 is a step diagram for explaining an example of the processing of the substrate W in the second embodiment. Hereinafter, refer to FIG. 21 and FIG. 22.

In an example of the processing of the substrate W in the second embodiment, steps S3-1 to S4-2 shown in FIG. 22 are performed instead of steps S3 to S4 shown in FIG. 5. The steps other than these are the same as step S1 to step S2 and step S5 to step S11 shown in FIG. 5. Therefore, steps S3-1 to S4-2 will be described below.

In addition, an example of sequentially supplying hydrofluoric acid and SC1 (a mixed liquid of ammonia, hydrogen peroxide, and water) to the silicon wafer corresponding to the substrate W will be described below. The natural oxide film formed on the silicon wafer is removed from the silicon wafer by the supply of hydrofluoric acid. Thereby, silicon is exposed on the surface of the pattern P1. After that, SC1 is supplied to the silicon wafer. The silicon exposed on the surface of the pattern P1 is changed into silicon oxide by contact with SC1. Thereby, the surface of the pattern P1 changes from hydrophobic to hydrophilic. Therefore, the pre-drying treatment liquid is supplied to the silicon wafer when the surface of the pattern P1 is hydrophilic.

As shown in FIG. 22, after starting the rotation of the substrate W (step S2 in FIG. 22), the upper surface of the substrate W is supplied with hydrofluoric acid as an example of a chemical solution to form hydrofluoric acid covering the entire upper surface of the substrate W The first chemical liquid supply step of the acid liquid film (step S3-1 in FIG. 22).

Specifically, when the blocking member 51 is at the upper position and the at least one protective cover 24 is at the upper position, the nozzle moving unit 34 moves the liquid chemical nozzle 31 from the standby position to the processing position. After that, the chemical liquid valve 33 is opened, and the chemical liquid nozzle 31 starts to spray hydrofluoric acid. When a certain time has elapsed after the liquid medicine valve 33 is opened, the liquid medicine valve 33 is closed, and the discharge of hydrofluoric acid is stopped. After that, the nozzle moving unit 34 moves the chemical liquid nozzle 31 to the standby position.

After the hydrofluoric acid ejected from the chemical liquid nozzle 31 collides with the upper surface of the substrate W rotating at the liquid supply speed, it flows outward along the upper surface of the substrate W by centrifugal force. Therefore, hydrofluoric acid is supplied to the entire upper surface of the substrate W, and a liquid film of hydrofluoric acid covering the entire upper surface of the substrate W is formed. When the chemical liquid nozzle 31 ejects hydrofluoric acid, the nozzle moving unit 34 can move the landing position of the hydrofluoric acid on the upper surface of the substrate W through the center and the outer periphery, or make the landing position stationary. In the central part.

Then, a first rinse liquid supply step of supplying pure water as an example of a rinse liquid to the upper surface of the substrate W to rinse the hydrofluoric acid on the substrate W is performed (step S4-1 in FIG. 22).

Specifically, in a state where the blocking member 51 is located at the upper position and at least one protective cover 24 is located at the upper position, the nozzle moving unit 38 moves the washing liquid nozzle 35 from the standby position to the processing position. After that, the flushing liquid valve 37 is opened, and the flushing liquid nozzle 35 starts to spray the flushing liquid. Before starting to spray pure water, the protective cover lifting unit 27 may also move the at least one protective cover 24 vertically to switch the protective cover 24 that receives the liquid discharged from the substrate W. When a certain time has elapsed after the flushing liquid valve 37 is opened, the flushing liquid valve 37 is closed to stop the spraying of the flushing liquid. After that, the nozzle moving unit 38 moves the rinse liquid nozzle 35 to the standby position.

After the pure water sprayed from the rinse liquid nozzle 35 collides with the upper surface of the substrate W rotating at the liquid supply speed, it flows outward along the upper surface of the substrate W by centrifugal force. The hydrofluoric acid on the substrate W is replaced with pure water sprayed from the rinse liquid nozzle 35. Thereby, a liquid film of pure water covering the entire upper surface of the substrate W is formed. When the rinsing liquid nozzle 35 sprays pure water, the nozzle moving unit 38 can move the impingement position of the pure water on the upper surface of the substrate W through the center and the outer periphery, or make the impingement position stand still in the center. Department.

Then, a second chemical solution supply step is performed to supply SC1 as an example of the chemical solution to the upper surface of the substrate W to form a liquid film covering SC1 on the entire upper surface of the substrate W (step S3-2 in FIG. 22).

Specifically, in a state where the blocking member 51 is at the upper position and at least one shield 24 is at the upper position, the nozzle moving unit 34B moves the second chemical liquid nozzle 31B from the standby position to the processing position. After that, the second chemical liquid valve 33B is opened, and the second chemical liquid nozzle 31B starts the discharge of SC1. When a certain time elapses after the second liquid medicine valve 33B is opened, the second liquid medicine valve 33B is closed, and the discharge of SC1 is stopped. After that, the nozzle moving unit 34B moves the second chemical liquid nozzle 31B to the standby position.

After SC1 ejected from the second chemical liquid nozzle 31B collides with the upper surface of the substrate W rotating at the liquid supply speed, it flows outward along the upper surface of the substrate W by centrifugal force. The pure water on the substrate W is replaced with SC1 sprayed from the second chemical liquid nozzle 31B. As a result, a liquid film SC1 covering the entire upper surface of the substrate W is formed. When the second chemical liquid nozzle 31B ejects SC1, the nozzle moving unit 34B can move the landing position of SC1 on the upper surface of the substrate W through the center and the outer periphery, or make the landing position stand still at the center. Department.

Then, a second rinse liquid supply step of supplying pure water as an example of a rinse liquid to the upper surface of the substrate W to rinse SC1 on the substrate W is performed (step S4-2 in FIG. 22).

Specifically, in a state where the blocking member 51 is located at the upper position and at least one protective cover 24 is located at the upper position, the nozzle moving unit 38 moves the washing liquid nozzle 35 from the standby position to the processing position. After that, the flushing liquid valve 37 is opened, and the flushing liquid nozzle 35 starts to spray the flushing liquid. Before starting the spraying of pure water, the protective cover lifting unit 27 may also vertically move the at least one protective cover 24 to switch the protective cover 24 that receives the liquid discharged from the substrate W. When a certain time has elapsed after the flushing liquid valve 37 is opened, the flushing liquid valve 37 is closed to stop the spraying of the flushing liquid. After that, the nozzle moving unit 38 moves the rinse liquid nozzle 35 to the standby position.

After the pure water sprayed from the rinse liquid nozzle 35 collides with the upper surface of the substrate W rotating at the liquid supply speed, it flows outward along the upper surface of the substrate W by centrifugal force. The SC1 on the substrate W is replaced with pure water sprayed from the rinse liquid nozzle 35. Thereby, a liquid film of pure water covering the entire upper surface of the substrate W is formed. When the rinsing liquid nozzle 35 sprays pure water, the nozzle moving unit 38 can move the impingement position of the pure water on the upper surface of the substrate W through the center and the outer periphery, or make the impingement position stand still in the center. Department.

After the second rinse liquid supply step (step S4-2 in FIG. 22) is performed, the substrate W is sequentially supplied with the replacement liquid and before drying in the same manner as in the example of the processing of the substrate W in the first embodiment shown in FIG. Treat the liquid (step S5 to step S6 in FIG. 22), and sublime the solidified body 101 (refer to FIG. 23E) on the surface of the substrate W (step S7 to step S9 in FIG. 22). After that, the substrate W is carried out from the chamber 4 (step S10 to step S11 in FIG. 22). Thereby, the processed substrate W is carried out from the chamber 4.

Next, the phenomenon assumed to occur on the surface of the pattern P1 supplied with the pre-drying treatment liquid will be described.

23A to 23F are cross-sectional views of the substrate W for explaining this phenomenon. In Figures 23A to 23E, tertiary butanol is represented as TBA. In FIGS. 23A to 23C, the thick straight line represents the hydrophilic group of the tertiary butanol molecule, and the black circle represents the hydrophobic group of the tertiary butanol molecule.

As described above, in an example of the processing of the substrate W in the second embodiment, hydrofluoric acid and SC1 are sequentially supplied to the silicon wafer corresponding to the substrate W. The surface of the pattern P1 is changed to hydrophobic by the supply of hydrofluoric acid. After that, the surface of the pattern P1 is changed to hydrophilic by the supply of SC1. Therefore, the drying pre-treatment liquid containing camphor, IPA, and tertiary butanol is supplied to the silicon wafer when the surface of the pattern P1 is hydrophilic.

Camphor can be regarded as a hydrophobic substance, and tertiary butanol is an amphiphilic molecule containing a hydrophilic group and a hydrophobic group. As shown in FIG. 23A, since the surface of the pattern P1 is hydrophilic, the hydrophilic group of the tertiary butanol molecule is drawn to the surface of the pattern P1. Thereby, as shown in FIG. 23B, the hydrophilic group of the tertiary butanol molecule is adsorbed on the surface of the pattern P1, and a thin film of tertiary butanol is formed on the side surface Ps and the upper surface Pu of the pattern P1.

FIG. 23B shows an example of forming a monomolecular film of tertiary butanol along the surface of the pattern P1. As shown in FIG. 23C, in the case of this example, the hydrophobic group of the camphor molecule is attached to the hydrophobic group of the third butanol molecule adsorbed on the surface of the pattern P1. When a laminated film of tertiary butanol is formed along the surface of the pattern P1, the hydrophobic group of the camphor molecule is attached to the hydrophobic group of the tertiary butanol molecule exposed on the surface of the laminated film. Thereby, the camphor is maintained on the surface of the pattern P1 through the film of tertiary butanol.

As shown in FIG. 23C, the camphor molecules in the pre-drying treatment solution are attached to the camphor molecules held in the tertiary butanol film. Due to this phenomenon, a large number of camphor molecules are maintained on the side surface Ps of the pattern P1 through the molecular layer of tertiary butanol. Therefore, as shown in FIG. 23D, a sufficient amount of camphor molecules enter between the patterns P1. FIG. 23D shows an example in which a thin film of tertiary butanol is formed not only on the side surface Ps and the upper surface Pu of the pattern P1, but also on the bottom surface Pb of the recess formed between two adjacent patterns P1.

The IPA, which is equivalent to the solvent, is formed along the surface of the pattern P1 with a thin film of tertiary butanol, and a plurality of camphor molecules evaporate from the pre-drying treatment solution while being held on the surface of the pattern P1 through the thin film of tertiary butanol. As the IPA evaporates, the freezing point of the treatment solution before drying rises, and the concentration of camphor and tert-butanol rises. Thereby, as shown in FIG. 23E, a solidified body 101 including camphor and tertiary butanol is formed on the surface of the substrate W. Thereafter, as shown in FIG. 23F, the solidified body 101 is vaporized and removed from the surface of the substrate W.

According to research conducted by the inventors, it has been confirmed that when a silicon plate-like sample formed with a pattern P1 is used instead of the substrate W to process the substrate W of the second embodiment, if camphor, IPA, and tertiary butanol are used When the solution is used as the pre-drying treatment liquid, compared with the case where a solution of camphor and IPA is used as the pre-drying treatment liquid, the slump rate of the pattern P1 is reduced. Changing the concentration of tertiary butanol (volume percentage concentration) within the range of 0.1 vol%~10 vol%, the result is that there is no significant difference in the collapse rate of pattern P1. Therefore, if tertiary butanol is added even in a small amount, the collapse rate of the pattern P1 will also decrease. The concentration of tertiary butanol may be a value within the above range or a value outside the above range.

In the second embodiment, in addition to the effects of the first embodiment, the following effects can be achieved. Specifically, in the second embodiment, a pre-drying treatment liquid containing an adsorbent in addition to a sublimable substance and a solvent is supplied to the surface of the substrate W on which the pattern P1 is formed. After that, the solvent was evaporated from the pre-drying treatment liquid. Thereby, a solidified body 101 containing a sublimable substance is formed on the surface of the substrate W. Thereafter, the solidified body 101 on the substrate W is changed into a gas without passing through the liquid. Thereby, the solidified body 101 is removed from the surface of the substrate W. Therefore, compared with previous drying methods such as spin drying, the collapse rate of the pattern P1 can be reduced.

Sublimation substances are substances that contain hydrophobic groups in their molecules. The adsorbent is a substance containing a hydrophobic group and a hydrophilic group in the molecule. The hydrophilicity of the adsorbed material is higher than that of the sublimable material. Regardless of whether the surface of the pattern P1 is either hydrophilic or hydrophobic, or even if the surface of the pattern P1 contains a hydrophilic part and a hydrophobic part, the adsorbed substances in the treatment solution before drying will be adsorbed on the surface of the pattern P1 .

Specifically, when the surface of the pattern P1 is hydrophilic, the hydrophilic group of the adsorbing substance in the treatment solution before drying is attached to the surface of the pattern P1, and the hydrophobic group of the sublimation substance in the treatment solution before drying is attached to the adsorbing substance The hydrophobic base. Thereby, the sublimable substance is held on the surface of the pattern P1 via the adsorbing substance. When the surface of the pattern P1 is hydrophobic, at least the hydrophobic base of the sublimation substance is attached to the surface of the pattern P1. Therefore, no matter whether the surface of the pattern P1 is either hydrophilic or hydrophobic, or the surface of the pattern P1 contains a hydrophilic part and a hydrophobic part, the sublimable substance will be kept in the pattern P1 before the solvent evaporates. The surface or its vicinity.

When the sublimation substance is hydrophilic and the surface of the pattern P1 is hydrophilic, the sublimation substance is drawn to the surface of the pattern P1 by electrical attraction. On the other hand, when the sublimation substance is hydrophobic and the surface of the pattern P1 is hydrophilic, the attraction force is weak or does not generate such attraction force, so the sublimation substance is difficult to adhere to the surface of the pattern P1. Furthermore, when the sublimation substance is hydrophobic, the surface of the pattern P1 is hydrophilic, and the interval between the patterns P1 is extremely narrow, it is considered that a sufficient amount of the sublimation substance will not enter between the patterns P1. These phenomena also occur when the sublimation material is hydrophilic and the surface of the pattern P1 is hydrophobic.

If the solvent is evaporated in a state where there is no sublimable substance on or near the surface of the pattern P1, the solvent in contact with the surface of the pattern P1 exerts a collapsing force on the pattern P1, and the pattern P1 may collapse. It is also believed that if the solvent is evaporated in a state where there is no sufficient amount of sublimable material between the patterns P1, the gaps between the patterns P1 are not filled by the solidified body 101, and the pattern P1 collapses. If a sublimable substance is placed on the surface of the pattern P1 or near it before the solvent is evaporated, such collapse can be reduced. In this way, the collapse rate of the pattern P1 can be reduced.

In the second embodiment, not only the sublimable substance has sublimation properties, but the adsorbent substance also has sublimation properties. The adsorbed substance changes from a solid to a gas without passing through a liquid at room temperature or pressure. When at least a part of the surface of the pattern P1 is hydrophilic, the solvent evaporates in a state where the adsorbent in the treatment solution before drying is adsorbed on the surface of the pattern P1. The adsorbed substance on the surface of the pattern P1 changes from liquid to solid. Thereby, the solidified body 101 including the adsorbing substance and the sublimable substance is formed. After that, the solid of the adsorbed substance changes into a gas without passing through the liquid on the surface of the pattern P1. Therefore, compared with the case where the liquid is vaporized on the surface of the pattern P1, the collapse force can be reduced.

In the second embodiment, the surface of the substrate W is supplied with a pre-drying treatment liquid having a relatively low concentration of adsorbed substances. When at least a part of the surface of the pattern P1 is hydrophilic, the hydrophilic group of the adsorbing substance is attached to the surface of the pattern P1, and a monomolecular film of the adsorbing substance is formed along the surface of the pattern P1. If the concentration of the adsorbed substance is relatively high, a plurality of monomolecular films will accumulate to form a laminated film of the adsorbed substance along the surface of the pattern P1. In this case, the sublimable substance is held on the surface of the pattern P1 via the laminated film of the adsorbed substance. If the layered film of adsorbed substances is thicker, the sublimable substances entering between the patterns P1 will decrease. Therefore, by reducing the concentration of the adsorbed substance, more sublimable substances can enter between the patterns P1.

In the second embodiment, a pre-drying treatment liquid containing a sublimable substance whose hydrophobicity is higher than that of an adsorbed substance is supplied to the surface of the substrate W. Since either of the sublimation substance and the adsorption substance contains a hydrophobic group, when at least a part of the surface of the pattern P1 is hydrophobic, both the sublimation substance and the adsorption substance can be attached to the surface of the pattern P1. However, the affinity between the sublimation substance and the pattern P1 is higher than the affinity between the adsorption substance and the pattern P1, so more sublimation substances are attached to the surface of the pattern P1 than the adsorption substance. In this way, more sublimable substances can be attached to the surface of the pattern P1.

Other implementation forms

The present invention is not limited to the content of the above-mentioned embodiment, and various modifications can be made.

For example, in order to change the thickness T1 of the solidified body 101, conditions other than the concentration of the treatment liquid before drying may be changed. For example, in addition to changing the concentration of the pre-drying treatment liquid, the temperature of the pre-drying treatment liquid may be changed, or the temperature of the pre-drying treatment liquid may be changed instead of changing the concentration of the pre-drying treatment liquid.

The pattern P1 is not limited to a single-layer structure, and may be a multilayer structure. It is also possible to form at least a part of the pattern P1 with materials other than silicon. For example, at least a part of the pattern P1 may be formed by metal.

In an example of the processing of the substrate W in the first and second embodiments, in order to maintain the pre-drying treatment liquid on the substrate W as a liquid, it is also possible to maintain the pre-drying treatment liquid on the substrate W higher than the pre-drying treatment. The step of maintaining the temperature of the liquid whose freezing point is lower than the boiling point of the treatment liquid before drying.

When the rinse liquid on the substrate W such as pure water is replaced with the pre-drying treatment liquid, the pre-drying treatment liquid supply step may be performed without the replacement liquid supply step of replacing the rinse liquid on the substrate W with the replacement liquid.

In an example of the processing of the substrate W in the second embodiment, the surface of the pattern P1 may be hydrophilic from the beginning before being carried into the substrate processing apparatus 1. In this case, the second chemical solution supply step (Step S3-2 in FIG. 22) and the second rinse solution supply step (Step S4-2 in FIG. 22) may also be omitted. Furthermore, the chemical liquid supplied to the substrate W in the first chemical liquid supply step (step S3-1 in FIG. 22) may be a chemical liquid other than hydrofluoric acid.

In an example of the processing of the substrate W in the second embodiment, when the pre-drying treatment liquid is supplied to the surface of the substrate W, the surface of the pattern P1 may be hydrophobic. In this case, the surface of the pattern P1 may be hydrophobic from the beginning, or may be changed to hydrophobic when the substrate W is processed.

In the second embodiment, if the initial concentration of the sublimable substance (the concentration of the sublimable substance in the drying pretreatment solution before being supplied to the substrate W) is not changed, the first tank 87A shown in FIG. 3 may be omitted. And one of the second groove 87B.

In the second embodiment, the adsorbent may be mixed into the solution of the sublimable substance and the solvent outside the first tank 87A and the second tank 87B. In this case, the adsorbed substance may be mixed before the solution of the sublimable substance and solvent is sprayed from the pre-drying treatment liquid nozzle 39, or it may be mixed after the solution of the sublimable substance and the solvent is sprayed from the pre-drying treatment liquid nozzle 39. In the latter case, the adsorbed substance can be mixed in the solution of the sublimable substance and solvent in the space between the pre-drying treatment liquid nozzle 39 and the substrate W, or it can be mixed in the sublimable substance and solvent on the upper surface of the substrate W. In solution.

The blocking member 51 may include, in addition to the circular plate portion 52, a cylindrical portion extending downward from the outer periphery of the circular plate portion 52. In this case, if the blocking member 51 is arranged at the lower position, the substrate W held by the spin chuck 10 is surrounded by the cylindrical portion.

The blocking member 51 may also rotate around the rotation axis A1 together with the rotating chuck 10. For example, the blocking member 51 may be placed on the rotating base 12 so as not to contact the substrate W. In this case, since the blocking member 51 is connected to the rotating base 12, the blocking member 51 rotates in the same direction as the rotating base 12 at the same speed.

The blocking member 51 may also be omitted. Among them, when a liquid such as pure water is supplied to the lower surface of the substrate W, it is preferable to provide a blocking member 51. The reason is that the blocking member 51 can block the droplets that move from the lower surface of the substrate W to the upper surface of the substrate W along the outer peripheral surface of the substrate W, or the droplets that splash to the inside from the processing cup 21, thereby reducing The liquid mixed in the pre-drying treatment liquid on the substrate W.

The substrate processing apparatus 1 is not limited to an apparatus for processing a disc-shaped substrate W, and may be an apparatus for processing a polygonal substrate W.

The substrate processing device 1 is not limited to a single-chip device, and may also be a batch-type device that processes a plurality of substrates W at a time.

It is also possible to combine two or more of all the above-mentioned configurations. It is also possible to combine two or more of the above-mentioned steps.

The pre-drying treatment liquid nozzle 39 is an example of a pre-drying treatment liquid supply unit. The center nozzle 55 and the rotation motor 14 are an example of a solidified body forming unit. The center nozzle 55 and the rotating motor 14 are also examples of the sublimation unit.

The embodiments of the present invention are described in detail, but these are only specific examples used to clarify the technical content of the present invention. The present invention should not be limited and interpreted by these specific examples. The spirit and scope of the present invention are only subject to the accompanying Limitation of the scope of patent application. [Cross-reference of related applications]

This application claims priority based on Japanese Patent Application No. 2018-119092 filed on June 22, 2018 and Japanese Patent Application No. 2019-050214 filed on March 18, 2019. All of these applications The content is incorporated here by reference.

1: Substrate processing equipment 2: processing unit 2w: wet processing unit 3: control device 3a: Computer body 3b: Peripheral devices 4: chamber 5: The partition wall 5a: air outlet 5b: Moving in and out 6: FFU 7: Baffle 8: Exhaust duct 9: Exhaust valve 10: Rotating chuck 11: Chuck pin 12: Rotating base 12u: upper surface 13: Rotation axis 14: Rotating motor 21: Handling the cup 22: Outer wall components 23: Cup 24: Protective cover 24u: upper end 25: Cylinder 26: top wall 27: Protective cover lifting unit 31: Liquid Nozzle 31B: 2nd chemical liquid nozzle 32: Liquid piping 32B: 2nd chemical liquid piping 33: Liquid valve 33B: 2nd chemical liquid valve 34: Nozzle moving unit 34B: Nozzle moving unit 35: Flushing fluid nozzle 36: Flushing fluid piping 37: Flushing fluid valve 38: Nozzle moving unit 39: Nozzle of treatment liquid before drying 40: Pre-drying treatment liquid piping 41: Treatment liquid valve before drying 42: Nozzle moving unit 43: Replacement fluid nozzle 44: Replacement fluid piping 45: Replacement fluid valve 46: Nozzle moving unit 51: Interrupting member 51L: lower surface 52: Disc section 53: fulcrum 54: Interrupting member lifting unit 55: Center nozzle 56: Upper gas piping 57: Upper gas valve 58: Flow adjustment valve 59: Upper temperature regulator 61: Upper central opening 62: Upper gas flow path 63: Upper gas piping 64: Upper gas valve 65: Flow adjustment valve 66: Upper temperature regulator 71: Nozzle on the lower surface 72: Heating fluid piping 73: Heating fluid valve 74: Flow adjustment valve 75: Lower heater 76: Cooling fluid piping 77: Cooling fluid valve 78: Flow adjustment valve 79: cooler 81: Lower central opening 82: Lower gas flow path 83: Lower gas piping 84: Lower gas valve 85: Flow adjustment valve 86: Lower temperature regulator 87A: Slot 1 87B: Slot 2 88A: 1st loop piping 88B: 2nd cycle piping 89A: 1st pump 89B: 2nd pump 90A: 1st separation piping 90B: Second separation piping 91A: The first on-off valve 91B: The second on-off valve 92A: The first flow adjustment valve 92B: 2nd flow control valve 93: CPU 94: Main memory device 95: auxiliary memory device 96: Reading device 97: communication device 98: input device 99: display device 101: solidified body A1: Rotation axis C: carrier CR: Central Robot H1: Robotic hand H2: Robotic hand Hp: height IR: Indexing robot LP: Load port M: removable media P: program P1: Pattern Pb: bottom surface Ps: side Pu: upper surface T1: thickness TW: Tower W: substrate

Fig. 1A is a schematic view of the substrate processing apparatus of the first embodiment of the present invention viewed from above.

Fig. 1B is a schematic view of the substrate processing apparatus viewed from the side.

Fig. 2 is a schematic view of the inside of the processing unit included in the substrate processing apparatus viewed horizontally.

Fig. 3 is a schematic diagram showing a pre-drying treatment liquid supply unit included in the substrate processing apparatus.

Figure 4 is a block diagram showing the hardware of the control device.

Fig. 5 is a step diagram for explaining an example of substrate processing in the first embodiment.

FIG. 6A is a schematic diagram showing the state of the substrate when the substrate shown in FIG. 5 is processed.

FIG. 6B is a schematic diagram showing the state of the substrate when the substrate shown in FIG. 5 is processed.

FIG. 6C is a schematic diagram showing the state of the substrate when the substrate shown in FIG. 5 is processed.

FIG. 7 is a graph showing an example of the concept that the thickness of the liquid film of the pre-drying treatment liquid on the substrate decreases due to the evaporation of the solvent.

Fig. 8 is a graph showing an example of the relationship between the initial concentration of the sublimable substance and the thickness of the solidified body.

Fig. 9 is a table showing an example of the embedding rate and pattern collapse rate obtained when a plurality of samples formed with patterns of the same shape and strength are processed while changing the initial concentration of camphor.

Fig. 10 is a broken line chart showing the relationship between the concentration of camphor in Fig. 9 and the collapse rate of the pattern.

FIG. 11 is a broken line chart showing the relationship between the embedding rate and the collapse rate of the pattern in FIG. 9.

FIGS. 12A and 12B are schematic diagrams for explaining the mechanism assumed for the phenomenon that the collapse rate of the pattern becomes higher when the solidified body is too thick.

13A and 13B are schematic diagrams for explaining the mechanism assumed for the phenomenon that the pattern collapse rate becomes higher when the solidified body is too thin.

FIG. 14 is a table showing an example of the collapse rate of patterns obtained when a plurality of samples formed with patterns of the same shape and strength are processed while changing the initial concentration of camphor.

Fig. 15 is a table showing an example of the collapse rate of patterns obtained when a plurality of samples formed with patterns of the same shape and strength are processed while changing the initial concentration of camphor.

Fig. 16 is a table showing an example of the collapse rate of patterns obtained when a plurality of samples formed with patterns of the same shape and strength are processed while changing the initial concentration of camphor.

Fig. 17 is a broken line chart showing the relationship between the concentration of camphor and the collapse rate of the pattern in Fig. 14.

Fig. 18 is a broken line chart showing the relationship between the concentration of camphor in Fig. 15 and the collapse rate of the pattern.

Fig. 19 is a broken line chart showing the relationship between the concentration of camphor and the collapse rate of the pattern in Fig. 16.

Figure 20 is a chart formed by overlapping the broken lines of Figure 17 to Figure 19.

Fig. 21 is a schematic view of the inside of the processing unit included in the substrate processing apparatus of the second embodiment when viewed horizontally.

Fig. 22 is a step diagram for explaining an example of substrate processing in the second embodiment.

FIG. 23A is a cross-sectional view of a substrate for explaining a phenomenon assumed to occur on the surface of the pattern on which the pre-drying treatment liquid is supplied.

FIG. 23B is a cross-sectional view of the substrate for explaining this phenomenon.

FIG. 23C is a cross-sectional view of the substrate for explaining this phenomenon.

FIG. 23D is a cross-sectional view of the substrate for explaining this phenomenon.

FIG. 23E is a cross-sectional view of the substrate for explaining this phenomenon.

FIG. 23F is a cross-sectional view of the substrate for explaining this phenomenon.

Claims (12)

A substrate processing method, comprising: a pre-drying treatment liquid supply step of supplying a pre-drying treatment liquid to the surface of a substrate on which a pattern is formed. The pre-drying treatment liquid includes a sublimable substance that changes into a gas without passing through a liquid, and A solution of a solvent that dissolves each other with the sublimable substance; a solidified body forming step in which the solvent is evaporated from the pre-drying treatment liquid on the surface of the substrate to form the sublimable substance on the surface of the substrate The solidified body; and the sublimation step, which removes the solidified body from the surface of the substrate by sublimating the solidified body; and in the solidified body forming step, the thickness of the solidified body after a hundred times relative to the height of the pattern The value of the ratio exceeds 76 and does not reach 219. The substrate processing method of claim 1, wherein the sublimable substance includes at least one of camphor and naphthalene. The substrate processing method of claim 1 or 2, wherein the solvent includes at least one of IPA (isopropyl alcohol), acetone, and PGEE (propylene glycol monoethyl ether). Such as the substrate processing method of claim 3, wherein the solvent is IPA, and the mass percentage concentration of the sublimable substance in the pre-drying treatment liquid exceeds 0.62 and does not reach 2.06. The substrate processing method of claim 3, wherein the solvent is acetone, and the mass percentage concentration of the sublimable substance in the pre-drying treatment liquid exceeds 0.62 and is 0.96 or less. The substrate processing method of claim 3, wherein the solvent is PGEE, and the mass percentage concentration of the sublimable substance in the pre-drying treatment liquid exceeds 3.55 and is less than 6.86. The substrate processing method of claim 1 or 2, wherein the pre-drying treatment liquid supplied to the surface of the substrate in the pre-drying treatment liquid supply step contains the sublimable substance containing a hydrophobic group, the solvent, and A solution of a hydrophobic group and a hydrophilic group with a higher hydrophilicity than the adsorption substance of the above sublimation substance. The substrate processing method of claim 7, wherein the adsorbed substance is a substance with sublimation property. The substrate processing method of claim 7, wherein the concentration of the adsorbed substance in the pre-drying treatment liquid is lower than the concentration of the solvent in the pre-drying treatment liquid. The substrate processing method of claim 7, wherein the hydrophobicity of the sublimable substance is higher than that of the adsorbent substance. A substrate processing apparatus, comprising: a pre-drying treatment liquid supply unit, which supplies a pre-drying treatment liquid to the surface of a patterned substrate, the pre-drying treatment liquid includes a sublimable substance that changes into a gas without passing through a liquid, and A solution of a solvent in which the sublimable substance is mutually dissolved; a solidified body forming unit that evaporates the solvent from the pre-drying treatment liquid on the surface of the substrate to form a solidified substance containing the sublimable substance on the surface of the substrate Sublimation unit, which removes the solidified body from the surface of the substrate by sublimating it; and a control device that controls at least the solidified body forming unit; and the control device performs at least the following steps Programming: Based on the concentration of the pre-drying treatment solution specified by the process conditions, for the solidified body forming unit, the ratio of the thickness of the solidified body to the height of the pattern after a hundred times becomes more than 76 and less than 219 The solidified body is formed on the surface of the substrate. A pre-drying treatment liquid, which is a pre-drying treatment liquid supplied to the surface of the substrate before drying the surface of the patterned substrate, and contains a sublimable substance that changes into a gas without passing through a liquid, and the sublimable substance Mutual dissolving solvents, and adjust the concentration of the sublimable substance in the following manner: when the solvent is evaporated from the pre-drying treatment liquid on the surface of the substrate, the substrate containing the sublimable substance is formed on the surface of the substrate. When the solidified body is a hundred times later, the ratio of the thickness of the solidified body to the height of the pattern exceeds 76 and does not reach 219.

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