JP2009043854A - Wafer drying device, and wafer drying method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress formation of a watermark while effectively removing liquid remaining on a wafer surface with a simple structure without using IPA. <P>SOLUTION: In a drying device which dries a wafer W wetted with liquid L, a moisture-absorptive capillary structure 3 is disposed opposite the wafer W in contact with or in proximity to the wafer surface. While the capillary structure 3 is brought into contact with liquid L on the wafer W and one of the capillary structure 3 and wafer W is moved relatively to the other, the liquid L is wiped with the capillary structure 3 for water absorption and drying. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wafer drying apparatus and a wafer drying method, and more particularly to a wafer drying apparatus and a wafer drying method for drying a liquid such as a rinsing liquid adhering to or remaining on a wafer surface.

  Conventionally, after the wafer is cleaned with a rinse liquid, a liquid such as a rinse liquid adheres and remains on the wafer surface. When drying the liquid adhering / remaining on the wafer surface, for example, in the spin drying method, the wafer is rotated to centrifuge the liquid, and the liquid is dried by evaporation (see, for example, Patent Document 1).

  As another drying method, there is a drying method by far infrared heating or a drying method by blowing a drying gas. In the drying method by far-infrared heating, the draining block is arranged close to the wafer so as to face the wafer, and a gap is formed between the wafer and the draining block so that capillary action acts. A meniscus is formed between the wafers, and moisture is evaporated and dried while irradiating and heating the portion of the meniscus with far infrared rays.

  Here, the draining block is used for uniformly diffusing water between the draining block and the wafer. In this way, when water is uniformly diffused and the thin meniscus is irradiated with far infrared rays, the temperature at the tip of the meniscus increases, and the surface tension and viscosity of the water become smaller than other parts. .

  Using this principle, even if the water droplet on the tip side of the meniscus is pulled and thinned as the wafer moves, the surface tension and viscosity on the tip side are reduced accordingly. Therefore, the water droplet is thinly stretched, and the water film near the tip of the meniscus is torn off by the surface tension. As a result, the water film is prevented from forming water droplets, and the tip portion of the meniscus is evaporated and dried by heating with far-infrared rays while being in a thin water film state.

  In addition, the draining block itself does not have the effect | action of pulling up water by a capillary phenomenon (for example, refer patent document 2).

Also, in the drying method by spraying the drying gas, a liquid-tight layer is formed between the proximity member and the wafer so that a capillary phenomenon acts between the proximity member and the wafer, and the proximity member is formed on the wafer. A gas discharge means for injecting a drying gas onto the surface of the wafer is provided. The proximity member is located on the upstream side in the moving direction, and has a guide surface extending in a direction away from the wafer surface. The gas discharge means is disposed upstream of the proximity member in the moving direction, and is configured to discharge and dry the drying gas toward the liquid-tight layer (see, for example, Patent Document 3).
Japanese Patent No. 2922754 Japanese Patent No. 2983494 JP 2006-310756 A

In the prior art described in Patent Document 1, the wafer surface is dried by rotating the wafer at a high speed to apply a larger centrifugal force. However, the wafer surface, for example
In water-repellent wafers, it is difficult to completely remove minute water droplets when spin-dried. As a result, the wafer surface is naturally dried with minute water droplets remaining on the wafer surface, which is a thin film (silicon oxide film) As a result, the quality performance of the wafer is adversely affected.

  That is, in the cleaning and drying according to the conventional technique, a minute water droplet that has been centrifuged reacts with the wafer surface, whereby a water droplet residue called a watermark is formed on the wafer surface. In particular, since the surface of the wafer is made of a water-repellent Low-k material, minute water droplets that are not separated by centrifugal force remain on the wafer surface, and a watermark is easily formed. When the watermark is formed on the wafer surface in this manner, dust or the like adheres to the watermark, causing a signal delay (RC delay) or the like, thereby degrading device performance.

  In the prior art described in Patent Document 2, the water draining block uniformly diffuses water between the wafers and dries, but it is very difficult to adjust the gap between the wafer and the water draining block. Particularly, when the shape of the wafer is curved, it is necessary to manufacture the flatness of the draining block with high accuracy, and the apparatus becomes large.

  The mechanism of water evaporation itself is to elongate the water thinly and irradiate it with far infrared rays to evaporate it. That is, the portion where water is thinly drawn by capillary action is locally evaporated and dried by irradiation with far infrared rays. For this reason, a lot of equipment is required for the generation mechanism of far infrared rays, and the equipment cost becomes expensive.

  Furthermore, with the prior art described in Patent Document 3, it is difficult to accurately adjust the gap between the proximity member and the wafer. In particular, a device wafer flattened wafer handled here usually has uneven thickness and warpage on the substrate itself. In a 300 mm wafer, even a normal wafer that has not undergone a device process usually has a wafer warp of about 100 μm.

  In addition, various wafer processes, such as ion implantation, heat treatment, etching, CVD, CMP, etc., form complex compressive and tensile stresses on the wafer surface film. It depends on the device process and product. Also, a wafer having a warp amount of 100 μm or more usually exists.

  When such a wafer is dried from a wet state, even if, for example, the back surface of the wafer is vacuum-adsorbed and corrected in order to correct the warpage of the wafer, if the wafer is adsorbed in a wet state, a clear suction mark remains.

  For this reason, the wafer is supported on the periphery or placed on a flat surface, but in this state, the warp of the wafer mentioned above remains as it is. Therefore, it can be said that undulations of 100 μm or more normally exist on the wafer surface supported in a planar shape.

  It is obvious that it is obviously difficult to keep the proximity member at a certain distance from the wafer with the conventional technique described in Patent Document 3 for a wafer having such a warp. This is because even if the flatness of the proximity member and the drying head to which the proximity member is attached are manufactured with high accuracy, the interval cannot be kept constant due to undulations on the surface of the wafer itself.

  In particular, the watermark is generated by drying fine water droplets having a diameter of about several hundred μm. To remove it, the drying head also needs to be close to the wafer, but when the drying head itself is fixed to the wafer, the distance between the wafer and the adjacent member varies depending on the position of the wafer. The watermark may still remain where the gap is large.

  Furthermore, in this known example, the drying mechanism itself is drying by gas. It is obvious from the following description. In the paragraph [0028], “the gas supply unit 44 is operated to discharge nitrogen gas from the tip of the thin tube unit 46 as a drying gas”.

  Further, in the paragraph [0029], “nitrogen gas (drying gas) discharged from the narrow tube portion 46 is blown against the exposed interface 52, and the rinse liquid constituting the exposed interface 52 is changed to the substrate surface WS and the liquid. The substrate surface area corresponding to the exposed interface portion 52 is blown off from the dense layer 36 and dried. " That is, the drying mechanism is drying by blowing off with gas.

Here, there is a description using the capillary phenomenon, which is used to form a liquid-tight layer between the wafer and the adjacent member, as shown in paragraph [0012]. That is, a liquid tight layer is formed by feeding a liquid into the space between the proximity member and the wafer by capillary action.
The principle of drying itself does not use capillary action.

In the drying method using such a gas blowing method, a large number of water molecules may be blown off as a lump and discharged along the guide surface of the adjacent member, but some liquid is still separated, There is still a possibility of remaining watermarks on the wafer surface.
The watermark hardly occurs in a hydrophilic wafer, for example, a wafer having a thermal oxide film on the surface. A wafer in which a watermark is generated is particularly prominent when the surface is a hydrophobic or water-repellent wafer. This is because the water-repellent wafer repels water, so that the water is easily separated finely and the fine water remains as a result.

  For this reason, in order to prevent the generation of a watermark, it is required that the water is not separated finely, but is integrated as much as possible and the waterfront is retracted.

  Therefore, the most fundamentally different point of the prior art of Patent Document 3 from the present invention is the part of the drying mechanism. In principle, the water is separated and dried, or the water is integrated. The point is whether to dry while retreating the shore. Although the prior art of the said patent document 3 is the former, in this invention, the latter idea is employ | adopted.

  In CMP that is compatible with water-repellent low-k materials, the wafer is slowly pulled out of ultrapure water in an IPA vapor atmosphere and dried, or the IPA vapor is applied to the wafer rotation surface while rotating the wafer. A method of acting is adopted.

  In this case, in order to handle dangerous IPA vapor, it is necessary to install a large explosion-proof structure, which increases the cost. Moreover, it takes a lot of time to obtain the required drying effect. Also, the dried IPA remains on the wafer surface.

  Further, in a wafer having minute irregularities such as a device wafer, even if the film itself is water-repellent, hydrophilic portions are also present due to the concentration of minute irregularities as the surface shape. In particular, in IPA vapor drying and Marangoni drying, the waterfront is retracted by utilizing the Marangoni effect utilizing the difference in surface tension between the two liquids.

However, the Marangoni effect may be effective if the surface state of the wafer is extremely uniform and water-repellent. However, as described above, in the actual cleaning of the device wafer surface, the properties of the film are different. Regardless of the surface shape of the membrane, there are some parts that appear to be hydrophilic, and it is very difficult to control the water at a stable and constant level. There is a problem that leftovers occur. The Marangoni effect itself is caused by the difference in surface tension between two different liquids, which increases in proportion to the concentration gradient of the two liquids. If both liquids are not miscible, the concentration gradient will be relatively stable, which may result in a stable Marangoni effect.

  However, especially in the case of isopropyl alcohol (IPA) and water, they are miscible with each other, so there are various parts such as a part where the concentration gradient is remarkable and a part where there is no concentration gradient because it is already mixed. Such miscibility changes depending on the temperature at that time, that is, the degree of diffusion in which isopropyl alcohol diffuses into water.

  For this reason, it is very difficult to form a stable Marangoni force based on a stable concentration gradient. The result is a process that is susceptible to other disturbance factors. Therefore, it is difficult to stably eliminate the watermark (see, for example, Japanese Patent No. 3095438 and Japanese Patent Laid-Open No. 11-233481).

  Therefore, in the present invention, the following items 1 to 5 are specifically technical problems to be solved. That is, even in a wafer having a large warp such as a device wafer, water existing on the wafer is stably removed without generating a watermark (Item 1). In addition, water is not separated and blown away, but the water is smoothly and smoothly retracted, and in principle, water droplets are not left and fine watermarks are not formed (Item 2).

  Although the film composition itself is water-repellent due to the minute unevenness on the device wafer, the watermark is stable even if there are places that are considered hydrophilic in some places including the surface shape. (Matter 3). Also, avoid the use of dangers, chemicals, chemicals, or explosive chemicals, and eliminate the occurrence of watermarks with a simple device mechanism (Item 4). Furthermore, the entire wafer is efficiently dried in a short time and without a watermark without requiring a relatively long time (Item 5).

  The technical problem which should be solved by the point of said matter 1-5 arises, and this invention aims at solving this problem.

  The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 is a wafer drying apparatus for drying a liquid adhering to the wafer surface, wherein the moisture absorption is arranged opposite to the wafer surface. A capillary structure and a relative movement mechanism for moving the capillary structure relative to the wafer, the tip of the capillary structure being close to the liquid on the wafer surface, Provided is a wafer drying apparatus configured to absorb and remove liquid on the wafer surface while moving the capillary structure relative to the wafer.

  According to this configuration, the tip of the capillary structure is moved close to a position where it contacts the liquid (including minute water droplets) on the wafer by the relative movement mechanism, and then one of the capillary structure and the wafer is moved with respect to the other. And move relatively along the direction parallel to the wafer surface. As a result, the liquid on the wafer is absorbed and removed in the form of wiping off the water with the capillary structure integrated, instead of drying in the form of separating and blowing away as in the prior art. Since the water does not separate, no small water droplets remain, and as a result, no water marks remain due to the water droplets.

  In addition, water is prevented from forming as water droplets by making the capillary structure sufficiently close to the wafer at a distance smaller than the diameter of the water droplets, rather than being formed as water droplets. It becomes possible to cling to the structure, absorb it, and remove it by adsorption. Here, capillary action is used to remove the liquid.

  The capillary structure has a structure with a large surface area so that a capillary phenomenon works. That is, they are hairy, net-like, or foamed. When such a capillary structure is close to the wafer surface, water droplets are not formed on the wafer surface and cling to the capillary structure. When water droplets are formed on the wafer surface, the surface water droplet portion maintains the surface shape by the surface tension of water.

  However, when another hydrophilic solid approaches here, the water is separated from the solid (wafer) by the surface tension of the other solid (capillary structure) due to the interfacial tension with this separate solid. The liquid is transferred to the As a result, the liquid existing on the wafer moves together and smoothly to another solid surface, and as a result, the liquid on the wafer is removed and dried.

  It is obvious that the drying principle itself is not to blow off the liquid with a gas as described in Patent Document 3 and separate and dry the liquid. The liquid is dried while being transferred to another solid surface, and the drying principle itself utilizes the capillary phenomenon.

  According to a second aspect of the present invention, there is provided a wafer drying apparatus for drying a liquid adhering to a wafer surface, a hygroscopic capillary structure disposed opposite to the wafer surface, and the capillary structure with respect to the wafer. A relative movement mechanism for relatively moving, and a guide mechanism for maintaining a constant distance between the capillary structure and the wafer in a state where the tip of the capillary structure is in contact with the liquid on the wafer surface. The capillary structure is moved relative to the wafer to absorb the liquid on the wafer surface and dry while keeping the distance between the capillary structure and the wafer constant. A wafer drying apparatus is provided.

  According to this configuration, by bringing the capillary structure close to the liquid existing on the wafer and transferring the liquid from the wafer surface to the capillary structure surface without separating the liquid by capillary action, Smoothly transfer water and dry.

  In addition, regarding the proximity of the capillary structure to the wafer, the warp of the wafer is usually 100 μm or more in a 300 mm wafer, etc., and considering the level of the wafer holding mechanism for holding the wafer, the flatness of about several hundred μm It becomes. Therefore, when the gap between the capillary structure and the wafer is fixed as shown in, for example, the gap between the proximity member and the wafer shown in Patent Document 3, the gap varies depending on the location in the wafer. May not be able to create an effective proximity state and may not be able to utilize capillary action.

  Therefore, the capillary structure is configured to follow the surface of the wafer when moving relative to the wafer. Thereby, a stable gap between the wafer and the capillary structure is formed, and a stable proximity state can be formed regardless of the wavy shape of the wafer surface.

The invention according to claim 3 is characterized in that the guide mechanism is formed so as to keep the distance between the capillary structure and the wafer constant by utilizing the stress of a fluid such as gas or liquid. A wafer drying apparatus according to 2, is provided.

  According to this configuration, the distance of the capillary structure with respect to the wafer surface can be accurately maintained with a simple mechanism without using a complicated mechanism. Moreover, even if the wafer has waviness, the capillary structure can follow the surface shape of the wafer.

  According to a fourth aspect of the present invention, the relative movement mechanism supports the capillary structure so that the capillary structure can be moved up and down with respect to the wafer, and a fluid supply mechanism as the guide mechanism is provided in or near the capillary structure. And the fluid supply mechanism and the capillary structure are coupled to each other, and a fluid is supplied from the fluid supply mechanism to the wafer surface so as to keep a constant distance between the capillary structure and the wafer. The wafer drying apparatus according to claim 2 is provided.

According to this configuration, since the capillary structure can be moved up and down, followability to the wafer surface can be further ensured.
According to a fifth aspect of the present invention, the fluid supply mechanism is configured to supply a fluid along the wafer surface so that the capillary structure floats with respect to the wafer. A wafer drying apparatus is provided.

  According to this configuration, the fluid is supplied along the wafer surface from the upstream side, and the liquid is supplied to the wafer surface smoothly and preferably in a laminar flow state. As a result, the capillary structure is opposed to the wafer via the fluid, and a fluid lubrication state is formed.

  According to a sixth aspect of the present invention, there is provided the wafer drying apparatus according to the first or second aspect, wherein the capillary structure is made of a capillary, a mesh or a foam.

  According to this configuration, since the capillary structure made of a capillary, a net or a foam has a sufficiently large surface area, the interfacial tension between the liquid on the wafer surface and the capillary structure (solid) is increased. The water absorption speed and the water absorption capacity due to the capillary action against the water increase.

  The invention according to claim 7 provides the wafer drying apparatus according to claim 1 or 2, wherein the capillary structure has a polar functional group such as an ester bond, an amide bond, a urethane bond, or a cyano group.

  According to this configuration, since the capillary structure material itself has hydrophilic molecules based on polar functional groups, that is, polar molecules and hydrolyzable molecules similar to water, the action of binding to water by hydrogen bonding or the like is high. Become. Therefore, in addition to the capillary phenomenon (interface tension) due to the structural and physical configuration, a high binding action to chemical water is exhibited.

  The invention according to claim 8 provides the wafer drying apparatus according to claim 1, 2 or 7, wherein the capillary structure is made of a hygroscopic fiber material or a hygroscopic polymer material.

  According to this configuration, the capillary structure made of the hygroscopic fiber material or the hygroscopic polymer material has high hygroscopicity and water absorption retention for the liquid on the wafer.

  According to a ninth aspect of the present invention, the capillary structure has a drainage chamber provided with a decompression mechanism at the other end, and the liquid sucked up by the capillary structure is discharged by being evaporated and diffused under reduced pressure. 2, 7 or 8 is provided.

According to this configuration, the liquid sucked up by the capillary structure during wafer drying is quickly evaporated and dried from the periphery of the other end of the capillary structure under reduced pressure by the liquid discharge chamber with a pressure reducing mechanism. Accordingly, during the wafer drying, the liquid is continuously sucked and discharged from the tip end portion (liquid suction portion) of the capillary structure to the other end side.

  According to a tenth aspect of the present invention, the relative movement mechanism includes a wafer rotation mechanism that horizontally rotates the wafer, and a horizontal direction in a radial direction of the wafer while the capillary structure is in contact with or close to the rotation surface of the wafer. A wafer drying apparatus according to claim 1, further comprising a capillary structure moving mechanism unit to be moved.

  According to this configuration, when the capillary structure is brought into contact with the liquid on the wafer to absorb water, the wafer is rotated horizontally by the wafer rotation mechanism, and the capillary structure is moved to the center of the wafer by the capillary structure movement mechanism. Gradually move toward the outer periphery. Thereby, the liquid on the wafer surface is absorbed and removed from the center of the wafer toward the outer periphery.

  According to an eleventh aspect of the present invention, the relative movement mechanism includes a wafer pulling mechanism portion for pulling up the wafer in the tilt direction, and a capillary tube for reciprocating in the horizontal direction while the capillary structure is in contact with or close to the tilted surface of the wafer. A wafer drying apparatus according to claim 1, comprising a structure moving mechanism.

  According to this configuration, when the capillary structure is brought into contact with the liquid on the wafer surface to absorb water, the wafer is gradually lifted and moved in the inclined direction by the wafer pulling mechanism, and the capillary structure is a capillary structure. The moving mechanism for reciprocation is moved back and forth in the horizontal direction while being in contact with or close to the inclined surface of the wafer. As a result, the liquid on the wafer surface is absorbed and removed from the upper region in the tilt direction of the wafer toward the lower region.

  According to a twelfth aspect of the present invention, there is provided a wafer drying method for drying a liquid adhering to a wafer surface, the step of disposing a hygroscopic capillary structure at a position facing the wafer, and contacting the capillary structure with the wafer surface. Or bringing the tip of the capillary structure into contact with the liquid on the surface of the wafer close to the wafer, and moving the capillary structure relative to the wafer, the capillary structure with respect to the wafer And a wafer drying method for absorbing the liquid on the wafer surface while relatively moving the wafer.

  According to this method, the tip of the capillary structure is moved close to a position where it contacts the liquid on the wafer surface, and then one of the capillary structure and the wafer is moved in a direction parallel to the wafer surface with respect to the other. Move relative. Thereby, the liquid on the wafer surface is continuously absorbed by the capillary structure as the capillary structure moves relative to the wafer.

  The invention described in claim 13 is the wafer drying method according to claim 12, wherein the liquid sucked up by the tip of the capillary structure is sucked and discharged from the other end of the capillary structure while being evaporated and diffused under reduced pressure. I will provide a.

  According to this method, the liquid sucked up by the capillary structure during wafer drying is quickly evaporated and dried from the periphery of the other end of the capillary structure under reduced pressure. Accordingly, during the wafer drying, the liquid is sucked and discharged quickly and continuously from the tip end portion (liquid suction portion) of the capillary structure to the other end side.

According to the first aspect of the present invention, since the liquid on the wafer surface is absorbed by the capillary structure, the liquid on the wafer surface can be automatically and continuously absorbed, and the effect of removing and drying the liquid can be enhanced as compared with the conventional case. . In this case, since there is no liquid left on the wafer surface, the generation of watermarks can be suppressed and the quality performance of the wafer can be improved.

  In addition, since no explosive IPA is used, no explosion-proof structure is required, no dangerous IPA remains on the wafer surface as in the past, and the drying process can be carried out safely and easily. Costs can be reduced.

  According to the second aspect of the present invention, water can be smoothly transferred and dried by transferring the liquid from the wafer surface to the capillary structure surface without separating the liquid existing on the wafer.

  In addition, since the liquid present on the wafer is effectively transferred to the capillary structure by capillary action, the wafer surface can obtain a drying performance without a watermark.

  The invention described in claim 3 can maintain the distance of the capillary structure with respect to the wafer surface with a simple mechanism with high accuracy, and therefore does not require a complicated mechanism in addition to the effect of the invention described in claim 2. In addition, even in the case of a wavy wafer, the capillary structure can be made to follow the surface shape of the wafer, so that an appropriate proximity state of the capillary structure can be easily created, and as a result, the action of the capillary phenomenon This makes it possible to remove the liquid stably.

  The invention according to claim 4 has the same effect as the invention according to claim 3. That is, since the distance of the capillary structure with respect to the wafer surface can be accurately maintained with a simple mechanism, a complicated mechanism is not required in addition to the effect of the invention of claim 2. In addition, even in the case of a wavy wafer, the capillary structure can be made to follow the surface shape of the wafer, so that an appropriate proximity state of the capillary structure can be easily created, and as a result, the action of the capillary phenomenon This makes it possible to remove the liquid stably. In particular, since the capillary structure can be moved up and down, followability to the wafer surface can be further secured. In addition, a more stable distance between the wafer and the capillary structure can be maintained by balancing the discharge pressure of the fluid and the weight of the capillary structure on the wafer by, for example, discharging the fluid to the wafer surface. it can. As a result, an appropriate close state of the capillary structure is created, and the liquid can be removed more stably using the capillary phenomenon.

  According to the fifth aspect of the present invention, the fluid is supplied along the wafer surface, and the liquid is supplied to the wafer surface smoothly and preferably in a laminar flow state. As a result, the capillary structure is configured to face the wafer and its fluid, and a fluid lubrication state is formed. In addition to the effects of the invention of claim 4, the capillary structure is generated by the dynamic pressure of the liquid. Floats on the wafer or is in a semi-contact state, and the distance between the wafer and the capillary structure can always be kept constant with high accuracy. Therefore, an appropriate proximity state of the capillary structure is created, and as a result, more stable liquid removal using the capillary phenomenon becomes possible.

  According to the sixth aspect of the present invention, the water absorption speed and the water absorption capacity due to the capillary phenomenon with respect to the liquid are increased, so that the water absorption drying property on the wafer surface is improved in addition to the effects of the first or second aspect. In particular, since the capillaries, nets or foams constituting the capillary structure have a large surface area, when the capillaries are moved so as to wipe off the liquid, the liquid is agglomerated as a lump. Then, it is attached or adsorbed so as to wrap around the surface of the capillary structure (strongly). As a result, it is possible to prevent the remaining of the liquid and separation of minute water droplets, more reliably suppress the generation of the watermark, and dry the wafer surface cleanly.

According to the seventh aspect of the invention, since the capillary structure is made of a hydrophilic material, not only the principle of capillary action and / or the interfacial tension is exhibited, but also a chemical water absorption action for a liquid is exhibited. Therefore, in addition to the effect of the first or second aspect, the liquid on the wafer surface can be sucked up more efficiently and effectively.

  Since the invention according to claim 8 increases the hygroscopicity and water absorption retention of the capillary structure, in addition to the effect of the invention according to claim 1, 2 or 7, even when a large wafer is dried, The efficiency of drying can be improved by increasing the water absorption rate, the amount of water absorption or the drying speed of the liquid.

  According to the ninth aspect of the present invention, since the liquid sucked up by the capillary structure during wafer drying is continuously sucked and moved to the other end side of the capillary structure, it is discharged. In addition to the invention described in item 8, the principle of capillarity and / or water absorption by interfacial tension can be executed without interruption, and the quick drying performance is further improved.

  In the invention described in claim 10, since the liquid on the wafer surface is absorbed and removed from the central area to the outer peripheral area of the wafer, in addition to the invention described in claim 1, the generation of watermarks due to minute water droplets on the wafer surface Can be effectively suppressed, and the entire surface of the wafer can be absorbed and dried more efficiently and uniformly.

  In the invention described in claim 11, since the liquid on the wafer surface is absorbed and dried from the upper region to the lower region in the direction of inclination of the wafer, in addition to the invention described in claim 1, the entire surface of the wafer is more efficiently obtained. And can be dried uniformly.

  In particular, by pulling the wafer diagonally while the capillary structure is horizontally applied to the inclined surface of the wafer, the interfacial tension to the liquid by the capillary structure is uniform and stable, so that no particles remain on the wafer surface. As compared with the prior art, the watermark suppression effect is remarkable.

  In the twelfth aspect of the invention, the capillary structure can automatically and continuously absorb the liquid on the wafer surface to enhance the effect of removing and drying the liquid. In this case, since no liquid is left on the wafer surface, generation of watermarks can be suppressed.

  In the invention according to claim 13, in addition to the invention according to claim 12, since the liquid sucked up by the capillary structure during wafer drying is continuously moved to the other end side of the capillary structure and discharged. The principle of capillary action and / or water absorption by interfacial tension can be performed without interruption, and the quick-drying performance for all liquids on the wafer surface is further improved.

  In order to achieve the object of effectively removing the liquid remaining on the wafer surface and suppressing the generation of watermark without using IPA, the present invention dries the liquid adhering to the wafer surface. The apparatus comprises a hygroscopic capillary structure disposed to face the wafer surface, and a relative movement mechanism for moving the capillary structure relative to the wafer, and a tip portion of the capillary structure This was realized by absorbing and removing the liquid on the wafer surface while moving the capillary structure relative to the wafer in a state where the liquid crystal was in contact with the liquid on the wafer surface.

A preferred embodiment of the present invention will be described below with reference to FIGS. In this embodiment, the capillary structure having hygroscopicity absorbs water while wiping the liquid (rinse liquid such as ultrapure water) on the wafer and dries it. Specific drying methods include a rotary drying method in which water is absorbed and dried while moving the capillary structure from the center of the rotating wafer surface toward the outer periphery, or the capillary structure is brought into contact with and brought close to the inclined wafer surface. Further, there is a pulling drying method in which the wafer is absorbed and dried while being pulled in an inclined direction.

  (Example 1) FIG. 1 shows a drying apparatus 1 of a rotary drying system. In the figure, reference numeral 2 denotes a rotating disk (wafer stage, spin base) as a wafer rotating mechanism. The rotating disk 2 is driven by a motor (not shown), and a wafer W is mounted on the rotating disk 2 such as a chuck. The wafer chuck (fixed portion) 2A is detachably attached.

  A capillary structure 3 is arranged above the rotating disk 2 so as to face the upper surface of the wafer W. The capillary structure 3 is provided so as to be brought into contact with and close to the upper surface of the wafer W by a capillary structure moving mechanism 5 described later. Further, the capillary structure 3 is formed of a member having a large surface area, for example, a brush-like member or a linear member (hair-like body), a mesh-like member (net-like body), a PVA sponge, a foamed member, etc. .

  Here, as the capillary structure 3 or the like according to the present invention, one having the configuration illustrated in FIGS. 2A and 2B can be employed. That is, the capillary structure 3 is coupled to the fluid discharge nozzle 31 disposed adjacent thereto. The combined structure is referred to as a capillary structure unit U. The capillary structure unit U is supported so as to be able to move flexibly up and down with respect to the scan arm 32 that rotates horizontally.

  By supplying a predetermined amount of fluid (for example, water) F per unit time from the fluid discharge nozzle 31 to the surface of the wafer W, the capillary structure unit U can float on the wafer W. Further, the flying height of the capillary structure unit U is adjusted by the discharge pressure from the fluid discharge nozzle 31, and further, the height of the capillary structure unit U with respect to the wafer W is adjusted by the discharge pressure. By balancing the discharge pressure and the weight of the capillary structure unit U with each other, the fluid discharge pressure is appropriately adjusted so that the distance between the capillary structure 3 and the wafer W is appropriate.

  Here, the appropriate distance between the wafer W and the capillary structure 3 means that the capillary structure 3 is in a state where it comes into contact with the liquid present on the wafer W. The distance between the wafer W and the capillary structure 3 when the capillary structure 3 has passed through the liquid and is close enough that the liquid does not remain on the wafer W. Say.

  According to this configuration, even if the wafer W rotates and the surface of the wafer W slightly moves up and down due to the warpage of the wafer W itself and the planar accuracy of the wafer chuck (fixed portion) 2A, the capillary structure 3 Since it moves up and down flexibly following W, it becomes possible to keep the distance between the capillary structure 3 and the surface of the wafer W constantly constant.

  In another embodiment, as shown in FIGS. 3A and 3B, the wafer W is rotated and the capillary structure 3 is brought close to the wafer W. At this time, upstream of the capillary structure 3 A liquid is supplied along the wafer W from a liquid supply nozzle 33 provided on the side. Thus, fluid (water) F is interposed between the capillary structure 3 and the wafer W, and a fluid lubrication state is formed between the surface of the wafer W and the surface of the capillary structure 3. This creates a half-contact condition rather than a full contact.

  Also in this case, since the capillary structure unit U including the capillary structure 3 sucks up the fluid on the wafer W by capillary action while floating on the fluid F, water can be efficiently removed from the surface of the wafer W. It becomes possible.

  Further, even if the surface of the wafer W is wavy due to the warp of the wafer W or the like, the capillary structure 3 is in a fluid lubrication state between the surface of the wafer W. For this reason, the capillary structure 3 can stably follow the surface of the wafer W, and can constantly move relative to the wafer W while maintaining a constant distance from the wafer W. As a result, the liquid on the wafer W can be removed without forming a watermark.

  As shown in FIG. 4, the capillary structure 3 is brought into contact with or brought close to the surface of the wafer W from an oblique direction or a perpendicular direction with respect to the surface of the wafer W, whereby the capillary structure 3 is attached to the liquid L adhering to the surface of the wafer W. Can be inserted (contacted). As a result, the liquid L can be wiped off at the tip of the capillary structure 3 by using the principle of capillary action and / or the interfacial tension.

  Here, the terms “wiping” and “wiping” are used, but as a definition of this term in the present invention, a liquid existing on one solid surface is directly transferred to another solid surface by utilizing capillary action. Without being separated, it means that it is continuously transferred as it is.

  In the case of “wiping”, it is not always necessary to bring the solid into contact with the solid. It is only necessary to bring another solid surface close enough to touch the liquid present on one solid. As a result, if the adjacent solid surface is hydrophilic and has a sufficient surface area, the liquid will be drawn up by capillary action on another solid surface. When the action of the capillary action is continuously performed, the liquid existing on the solid surface can be transferred and removed.

  In this specification, the operation of removing the liquid from the solid surface by the above-described series of phenomena is expressed by the term “wiping” or “wiping”. Therefore, in the present invention, the terms “wiping” and “wiping” include a process of transferring a liquid by utilizing a capillary phenomenon.

  5 (a) and 5 (b) are explanatory diagrams showing the action when another hydrophilic solid is brought close to the liquid present on the solid surface. When the liquid L was placed on the surface of the solid S1, the surface of the liquid L was balanced by forming a round shape by the surface tension of the liquid L (interface tension T1 between the liquid and gas).

  However, as shown in FIG. 5B, when another solid S2 newly approaches the liquid L, interfacial tension acts between the liquid L and the newly adjacent solid S2. Therefore, the surface tension of the liquid L (interfacial tension T2 between the gas and the liquid) apparently decreases, and the interfacial tension between the newly adjacent solid S2 and the liquid L becomes dominant.

  Thus, when the surface area of the adjacent solid S2 is increased, the interfacial tension T2 increases, and the liquid L rises upward as a capillary phenomenon. Thus, the liquid L can be smoothly transferred from the surface of the solid S1 to the surface of the other solid S2 without separating the liquid L into droplets. As a result, no minute droplets are left on the surface of the first solid S1.

  The capillary structure 3 is made of a hygroscopic material, for example, a hygroscopic fiber material, a hygroscopic polymer material or a hygroscopic foam material, and has polar functional groups such as an ester bond, an amide bond, a urethane bond, and a cyano group. Have.

  Further, one end of a string-like or belt-like drainage medium 4 is connected to the capillary structure 3, and the drainage medium 4 is made of a material having high moisture absorption performance. Further, the other end side of the drainage medium 4 extends along the inside of a holding portion 6 and a horizontal arm 7 described later.

  In the illustrated example, the capillary structure 3 is provided so as to be vertically movable and horizontally movable by the moving mechanism unit 5. That is, the capillary structure 3 is moved relative to the surface of the wafer W by the moving mechanism 5 while being brought into contact with or close to the surface of the wafer W, so that the liquid L on the wafer W is wiped off by a suction method.

  The moving mechanism unit 5 is provided at a holding unit 6 that holds the capillary structure 3, a horizontal arm 7 having one end connected to the upper end of the holding unit 6 at a right angle, and the other end of the horizontal arm 7. And a liquid discharge portion 8. Further, driving means (not shown) are connected to the holding portion 6 and the horizontal arm 7 respectively, and the holding portion 6 and the horizontal arm 7 are vertically controlled and driven and controlled by the driving means. The other end side of the drainage medium 4 extends along the inside of the holding portion 6 and the horizontal arm 7 as described above.

  The liquid discharge part 8 has a drainage chamber 9 in which the other end of the drainage medium 4 is accommodated. Accordingly, the liquid L sucked into the capillary structure 3 from the surface of the wafer W by the principle of capillary action and / or the interfacial tension moves and reaches the drainage chamber 9 using the drainage medium 4 as a passage.

  The drainage chamber 9 is provided with a pressure reducing mechanism for reducing the internal pressure of the drainage chamber 9. That is, one end of an air pipe 10 is connected to the drain chamber 9 and the other end of the air pipe 10 is connected to a drain receiving portion (not shown). In the middle of the air pipe 10, a vacuum pump (forced decompression means) 11 with an on-off valve for evacuating the liquid and gas in the drain chamber 9 is installed.

  Therefore, the pressure in the drainage chamber 9 is reduced by driving the vacuum pump 11. For this reason, the liquid L that has soaked into the drainage medium 4 in the drainage chamber 9 is rapidly evaporated and diffused under reduced pressure in the drainage chamber 9 and dried under reduced pressure.

  Next, a process of drying the wafer W wet with the liquid L using the rotary drying type wafer drying apparatus 1 having the above configuration will be described. During drying, the liquid and gas in the drainage chamber 9 are evacuated constantly or intermittently by the vacuum pump 11.

  First, after placing and fixing the wafer W on the turntable 2, the turntable 2 is rotated at a predetermined speed by a motor drive. Next, after the capillary structure 3 is moved directly above the center of the wafer W by the moving mechanism 5, the capillary structure 3 is lowered and the tip of the capillary structure 3 contacts or approaches the surface of the wafer W. By doing so, the tip of the capillary structure 3 is brought into contact with the liquid L on the wafer W.

  In this case, the tip of the capillary structure 3 may be brought into contact with the surface of the wafer W, but preferably it is brought into contact with the liquid L on the surface of the wafer W by being brought close to each other so as not to come into contact.

  Thereafter, the capillary structure 3 is scanned from the center portion of the wafer W toward the outer peripheral portion, whereby the liquid L adhering to the upper surface of the wafer W is wiped off at the tip portion of the capillary structure body 3 by a suction method. That is, by utilizing the principle of capillary action and / or the interfacial tension, the liquid L on the entire upper surface of the wafer W is continuously adsorbed toward the outer peripheral direction at the tip of the capillary structure 3.

In the liquid L sucking process, the liquid L adsorbed from the wafer W to the capillary structure 3 moves into the drainage chamber 9 via the drainage medium 4. In this case, since the pressure in the drainage chamber 9 is reduced by the vacuum pump 11, the liquid L is continuously and rapidly discharged to the drain receiving part via the drainage medium 4. As a result, the liquid L soaked in the drainage medium 4 in the drainage chamber 9 is quickly evaporated and diffused and dried under reduced pressure due to the pressure drop in the drainage chamber 9.

  As described above, according to the rotary drying type wafer drying apparatus 1, the liquid L on the surface of the wafer W is automatically adsorbed and removed from the capillary structure 3 by the principle of capillary action and / or the interfacial tension. Further, since the capillary structure 3 is made of a hygroscopic material having a large surface area so that the principle of capillary action and / or interfacial tension can be remarkably exhibited, a large amount of liquid L can be absorbed continuously and efficiently. .

  In addition, according to the present invention, since no remaining water droplets are generated, the formation of watermarks is suppressed, and the quality performance of the wafer W is improved. In addition, since no dangerous IPA is used, there is no need to attach a large explosion-proof structure to the drying treatment facility.

  In addition, since the capillary structure 3 has a sufficient surface area and is made of a hydrophilic material, the interfacial tension between the liquid L and the solid is increased, and the liquid L is sucked up smoothly by the capillary structure 3. It is done. Accordingly, the surface of the wafer W is effectively dried while absorbing the water by the capillary structure 3.

  Furthermore, since the material of the capillary structure 3 has a hydrophilic polymer containing a polar functional group, that is, a polar molecule similar to water or a hydrolyzable molecule, the action of binding to water by hydrogen bonding is enhanced. . As a result, in addition to the structural / physical hydrophilic structure having water absorption performance, a high chemical bonding action to water is exhibited. Accordingly, the capillary structure 3 not only exhibits the capillary phenomenon principle and / or interfacial tension structurally and physically, but also has high chemical water absorption performance, so that water can be absorbed more effectively. .

  Furthermore, since the capillary structure 3 is made of a hygroscopic fiber material or a hygroscopic polymer material, the hygroscopic performance of the liquid L on the wafer W is further improved, and the drying efficiency is greatly increased.

  In this embodiment, the liquid L sucked up by the capillary structure 3 is sucked and moved to the other end of the drainage medium 4, but the liquid L at the other end of the drainage medium 4 is in a depressurized state in the drainage chamber 9. Evaporation and diffusion are continuously performed, so that the water absorption action by the principle of capillary action and / or interfacial tension proceeds continuously. For example, from the above description, the following conditions may be applied to implement the present invention.

  (Embodiment 2) Next, a pull-drying drying apparatus 22 according to the present invention will be described. The same members as those in the first embodiment are denoted by the same reference numerals and will be briefly described.

  In FIG. 3, reference numeral 23 denotes a processing tank for inclining and drying the rinsed wafer W, and the processing tank 23 has a bottom surface 24 inclined in an oblique direction. A wafer slide holding base (wafer stage) 25 is provided on the bottom surface 24 so as to be movable along the bottom surface 24. The wafer slide holding base 25 is configured to reciprocate in an arbitrary direction along the bottom surface 24 of the processing bath 23 by a driving means (not shown).

The wafer slide holding base 25 has a fixing portion 25A such as a chuck, and is configured such that the wafer W can be detachably mounted on the wafer slide holding base 25. In addition, a drain pipe 26 is attached to the lower end of the bottom surface 24 of the treatment tank 23 in the inclination direction,
The liquid L dropped from the wafer W onto the bottom surface 24 is discharged from the drain pipe 26 to an external drain receiving portion or the like.

  Further, a capillary structure 26 is provided above the wafer slide holding base 25, and the length of the capillary structure 26 is formed substantially equal to the diameter of the wafer W. The capillary structure 26 has a large surface area, for example, a brush-like member (material: nylon (trade name), vinyl acetate, etc.) or a linear member bundled with a thread-like member, a net-like member, a PVA sponge, a polyester nonwoven fabric, It is formed of any one of foamed members.

  Furthermore, when the capillary structure 26 is brought into contact with or close to the surface of the wafer W, the tip of the capillary structure 26 is brought into contact with the liquid L on the surface of the wafer W so as to be able to absorb water. Accordingly, the liquid L on the wafer W is wiped off automatically and continuously by the suction method using the principle of capillary action and / or the interfacial tension at the tip of the capillary structure 26.

  The capillary structure 26 is made of a hygroscopic fiber material, a hygroscopic polymer material, or a hygroscopic foam material, and has a polar functional group such as an ester bond, an amide bond, a urethane bond, or a cyano group.

  The capillary structure 26 is movably held by a moving mechanism 27 and is disposed so as to be in contact with and close to the wafer W. Therefore, the liquid L on the wafer W is wiped by the capillary structure 26 by moving the capillary structure 26 relative to the wafer W in a state where the tip of the capillary structure 26 is in contact with the liquid L. Is absorbed. The moving mechanism unit 27 includes a holding unit 28 that can move up and down and can tilt, and that holds the capillary structure 26, and a horizontally movable horizontal arm 29 having one end connected to the holding unit 28.

  The capillary structure 26 is connected to one end of the drainage medium 4 and the other end of the drainage medium 4 is accommodated in the drainage chamber 9 with a pressure reducing mechanism, so that the capillary structure is similar to the first embodiment. The liquid L sucked up by 26 may be dried under reduced pressure while evaporating and diffusing in the drainage chamber 9.

  Next, a process of drying the rinsed wafer W using the pulling-type wafer drying apparatus 22 will be described. First, the wafer W is placed and fixed on the wafer slide holder 25.

  Thereafter, the capillary structure 26 is arranged in a direction orthogonal to the inclination direction of the wafer slide holding base 25 by the moving mechanism 27. Then, the tip portion of the capillary structure 26 is brought into contact with the liquid L on the wafer W by bringing the tip portion of the capillary structure 26 into contact with or approaching the surface of the wafer W.

  Thus, as shown in FIG. 4, the capillary structure 26 is reciprocated along the inclination direction S of the wafer W and in the left-right direction (horizontal direction) H in FIG. 25 is gradually pulled up in the inclination direction S along the bottom surface 24 of the treatment tank 23. Thus, the liquid L on the wafer W is cleanly absorbed and removed by wiping with the tip of the capillary structure 26.

  As described above, in the illustrated example, the liquid L on the wafer W is sucked up at the tip of the capillary structure 26 by using the principle of capillary action and / or the interfacial tension, and from the upper part to the lower part in the inclination direction of the wafer W. Continue to absorb water and dry.

The pulling-type wafer drying apparatus 22 can achieve the same effects as the rotary drying-type wafer drying apparatus 1 according to the first embodiment. That is, since the capillary structure 26 is made of a hygroscopic material having a large surface area, the liquid L on the wafer W is sucked up continuously and automatically, and generation of watermarks is effectively suppressed. .

  Further, since the capillary structure 26 is made of a hydrophilic material, the interfacial tension between the liquid and the solid is increased, and the liquid L is efficiently sucked up on the surface of the capillary structure 26. As a result, the capillary structure The water absorption effect by 26 increases. In particular, since the material of the capillary structure 26 has a hydrophilic polymer due to the polar functional group, in addition to the principle of the capillary phenomenon and / or the water absorption action due to the interfacial tension, the chemical moisture absorption performance for the liquid L is improved. Thus, the water absorption speed or the water absorption efficiency is further increased.

  (Comparative example 1) An example of the drying system using the conventional Marangoni force is shown in FIG. In this drying method, after the wafer W is submerged in the ultrapure water DIW, the wafer W is gradually lifted from the ultrapure water DIW and dried in an IPA vapor and nitrogen gas atmosphere. However, when the wafer W is pulled up from the ultrapure water DIW, the water surface at the time of pulling becomes uneven and non-uniform. For this reason, there are disadvantages such as particles remaining on the surface of the wafer W due to the non-uniformity at the time of drawing, or a watermark being generated.

  In this regard, in the present invention, as shown in FIG. 8, the capillary structure 26 is reciprocated in the horizontal direction H on the inclined surface of the wafer W, and the wafer W is gradually pulled up in the inclined direction S and absorbed and dried. Accordingly, the contact area between the tip of the capillary structure 26 and the liquid L is aligned (uniform) by the interface tension, and a uniform and stable interface state is always ensured. As a result, there is no possibility that defects such as left-over particles or watermarks occur on the surface of the wafer W.

  The present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified one.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating a configuration of a wafer drying apparatus according to an embodiment of the present invention. The structural example of embodiment of the capillary structure unit etc. which concern on this invention is shown, (a) is a partial cross section front view, (b) is a top view. The other structural example of embodiment, such as a capillary structure unit which concerns on this invention, is shown, (a) is a partial cross section front view, (b) is a top view. Explanatory drawing which shows the liquid suction state by the front-end | tip part of the capillary structure which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the interfacial tension of a liquid on a solid surface according to the present invention, wherein (a) is an explanatory diagram illustrating the interfacial tension between a liquid and a gas, and (b) is an explanatory diagram illustrating the interfacial tension between the liquid and the solid. Explanatory drawing of the structure of a wafer drying apparatus which shows the other Example of this invention. Explanatory drawing which shows the raising state of the wafer which concerns on a comparative example. Explanatory drawing which shows the raising state of the wafer in the wafer drying apparatus which concerns on another Example.

Explanation of symbols

1 Rotating drying method dryer 2 Rotating disc (wafer rotating mechanism)
3 Capillary structure 4 Drainage medium 5 Movement mechanism for capillary structure (relative movement mechanism)
8 Liquid discharge part 9 Drainage chamber 11 Vacuum pump (decompression mechanism)
22 Lifting / drying system 25 Wafer slide holder (wafer lifting mechanism)
26 Capillary structure 27 Movement mechanism part for capillary structure (relative movement mechanism)
31 Fluid discharge nozzle (guide mechanism, fluid supply mechanism)
33 Liquid supply nozzle (guide mechanism, liquid supply mechanism)

Claims (13)

In a wafer drying device that dries the liquid adhering to the wafer surface,
A hygroscopic capillary structure disposed opposite to the wafer surface, and a relative movement mechanism for moving the capillary structure relative to the wafer;
While moving the capillary structure relative to the wafer while the tip of the capillary structure is in proximity to the wafer surface or in contact with a small amount of liquid, the liquid on the wafer surface is removed. A wafer drying apparatus configured to absorb and dry. In a wafer drying device that dries the liquid adhering to the wafer surface,
A hygroscopic capillary structure disposed opposite the wafer surface;
A relative movement mechanism for moving the capillary structure relative to the wafer;
A guide mechanism for maintaining a constant distance between the capillary structure and the wafer in a state where the tip of the capillary structure is in contact with the liquid on the wafer surface;
The capillary structure is configured to move relative to the wafer to absorb the liquid on the wafer and dry it while keeping the distance between the capillary structure and the wafer constant. Wafer drying equipment.   3. The wafer drying apparatus according to claim 2, wherein the guide mechanism is formed so as to maintain a constant distance between the capillary structure and the wafer by utilizing a stress of a fluid such as gas or liquid. The relative movement mechanism supports the capillary structure so as to be movable up and down with respect to the wafer,
A fluid supply mechanism as the guide mechanism is disposed in or near the capillary structure, and the fluid supply mechanism and the capillary structure are coupled to each other,
3. The wafer drying apparatus according to claim 2, wherein a distance between the capillary structure and the wafer is kept constant by supplying a fluid to the wafer surface from the fluid supply mechanism.   5. The wafer drying apparatus according to claim 4, wherein the fluid supply mechanism is configured to supply a fluid along the wafer surface and to float the capillary structure with respect to the wafer.   3. The wafer drying apparatus according to claim 1, wherein the capillary structure is made of a capillary, a mesh, or a foam.   3. The wafer drying apparatus according to claim 1, wherein the capillary structure has a polar functional group such as an ester bond, an amide bond, a urethane bond, or a cyano group.   8. The wafer drying apparatus according to claim 1, wherein the capillary structure is made of a hygroscopic fiber material or a hygroscopic polymer material.   The capillary structure has a drainage chamber provided with a pressure reducing mechanism at the other end, and the liquid sucked up by the capillary structure is discharged by being evaporated and diffused under reduced pressure. The wafer drying apparatus according to 7 or 8. The relative movement mechanism includes a wafer rotation mechanism that horizontally rotates the wafer, and a capillary structure movement mechanism that horizontally moves the capillary structure in a radial direction of the wafer while being in contact with or close to the rotation surface of the wafer. The wafer drying apparatus according to claim 1, further comprising: a section.   The relative movement mechanism includes a wafer pulling mechanism section for pulling up the wafer in an inclined direction, and a capillary structure moving mechanism section for reciprocating in the horizontal direction while the capillary structure is in contact with or close to the inclined surface of the wafer. The wafer drying apparatus according to claim 1, further comprising: In the wafer drying method of drying the liquid adhering to the wafer surface,
Arranging a hygroscopic capillary structure at a position facing the wafer;
Bringing the capillary structure into contact with or close to the wafer surface and bringing the tip of the capillary structure into contact with the liquid on the wafer surface; and
Moving the capillary structure relative to the wafer,
Wafer drying method comprising absorbing and removing liquid on the wafer surface while moving the capillary structure relative to the wafer   13. The wafer drying method according to claim 12, wherein the liquid sucked up by the tip of the capillary structure is sucked and discharged from the other end of the capillary structure while being evaporated and diffused under reduced pressure.