JP4683222B2 - Wafer cleaning and drying apparatus and wafer cleaning and drying method - Google Patents

Description

  The present invention relates to a wafer cleaning / drying method and a wafer cleaning / drying apparatus for cleaning and drying a wafer such as a semiconductor device or an electronic component.

  Wafers such as semiconductor devices and electronic components are subjected to various processes such as cutting and polishing in the course of manufacturing. For example, polishing of a wafer by CMP is performed by holding a wafer with a wafer holding head, pressing the wafer against a rotating polishing platen with a predetermined pressure, and a chemical polishing agent (hereinafter, “ (Referred to as "slurry").

  The wafer polished by such a wafer polishing apparatus is cleaned by the cleaning apparatus, and the slurry adhering to the wafer is removed. The cleaned wafer is dried by a drying device provided in the cleaning device or adjacent to the cleaning device.

  In the drying process, conventionally, spin drying or the like in which a wafer is rotated to remove surface moisture by centrifugal force has been performed. However, in spin drying, water may be separated into a plurality of water droplets and remain without being removed from the wafer. Especially in CMP corresponding to Cu / Low-K, the Low-K material is water repellent. There was a problem that the watermark remained on the wafer surface. In addition, there is a problem that particles remain due to rebounding of the splashed water droplets.

Therefore, at present, a wafer is placed in a cleaning solution such as pure water or deionized water, the cleaning solution is discharged, the wafer is pulled out from the cleaning solution vertically, and a gas of isopropyl alcohol (hereinafter referred to as IPA) is sealed. A Marangoni-type drying apparatus is proposed that performs drying while preventing residual particles by using the difference in surface tension between the cleaning liquid and the IPA gas by feeding into the cleaning tank (see, for example, Patent Document 1). ).
JP 2003-224104 A

  However, in the drying apparatus described in Patent Document 1, drying is performed by slowly pulling out the wafer from the cleaning liquid while blowing the vapor containing IPA on the wafer immersed in the cleaning liquid, but the Marangoni effect is effectively exhibited. It was very difficult to do.

  This is because when IPA is sprayed onto the cleaning liquid as a vapor, the IPA vapor is condensed at the gas-liquid interface portion of the cleaning liquid, and a surface tension difference occurs between the cleaning liquid and the IPA vapor. Since the amount of condensation on the liquid is very small, it takes a very long time to generate an effective surface tension difference.

  One of the major causes of this problem is that IPA is condensed on the surface of the cleaning liquid, while a part of IPA is dissolved in the cleaning liquid. Although IPA has a slower solubility in a cleaning solution compared to methyl alcohol and ethanol, since it has a hydroxyl group like methyl alcohol and ethanol, penetration into water and dissolution cannot be avoided.

  The Marangoni force increases in proportion to the concentration gradient of the two fluids. However, when IPA dissolves in the cleaning solution, an effective concentration gradient cannot be formed, and there is a difference in dissolution rate, resulting in variations in Marangoni force acting between the cleaning solution and IPA. As a result, the Marangoni effect cannot be effectively used on the surface of the wafer that is relatively lifted from the cleaning liquid, and a water droplet residue or the like may be generated in part. A portion of the remaining cleaning solution is taken into the wafer to form a watermark, causing a serious problem during device fabrication.

  The present invention has been made for such a problem, and is a wafer cleaning / drying apparatus for drying a wafer without leaving a cleaning solution on the wafer and cleaning / drying a high-quality wafer without generating a watermark. It is another object of the present invention to provide a wafer cleaning / drying method.

In order to achieve the above object, according to the present invention, the invention described in claim 1 includes a cleaning tank in which a cleaning fluid is filled and a wafer immersed in the first fluid is cleaned. When pulling up the wafer from the first fluid or discharging the first fluid, the surface tension is higher than the first fluid in the vicinity of the boundary line between the first fluid surface and the wafer surface. The first supply means for supplying the second fluid for drying the wafer by capillary action is relatively moved, the supply device and the wafer are relatively moved, and the second fluid is liquidated by surface tension. is characterized in that said first supply means to the distance that does not form a drop with a moving means Ru is close to the boundary line.

  According to the first aspect of the present invention, the polished wafer is immersed in the first fluid and is cleaned in a state where the polished wafer is tilted and placed in the cleaning tank. After the cleaning is completed, the wafer is pulled up from the first fluid or the first fluid is discharged, whereby a boundary line between the first fluid surface and the wafer surface is formed on the wafer surface. At this time, the second fluid having a surface tension smaller than that of the first fluid is moved to the vicinity of the boundary line by the first supply unit while the moving unit relatively moves the wafer and the first supply unit. It is supplied uniformly.

  Thereby, it becomes possible to supply IPA which is a very small amount of the second fluid having a high concentration near the boundary which is the gas-liquid interface. As a result, an effective concentration gradient is formed between the first fluid and the second fluid, and the wafer is efficiently and uniformly cleaned and dried.

  According to a second aspect of the present invention, in the first aspect of the invention, the first supply means includes a supply member formed of a linear member or a tubular member, and the tip of the supply member is in the vicinity of the boundary line. It is characterized by being close to the wafer surface.

  According to the invention of claim 2, the second fluid uniformly supplied to the first supply means is constantly supplied at a constant flow rate even if it is a very small amount due to the effect of capillary action or the like caused by the interfacial tension. Flow through the member. The second fluid that has flowed to the tip of the supply member is continuously supplied to the wafer surface near the boundary line little by little by the interfacial tension acting between the supply member and the wafer surface, and the relative pulling speed of the wafer is increased. By adjusting, uniform drying is performed on the entire wafer surface.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the supply member is formed of a polymer resin material.

  According to the invention of claim 3, the supply member is made of a polymer resin material such as nylon, polyethylene, vinyl acetate, etc., and the wafer, the first fluid dipping the wafer, and the second fluid are caused by metal. Therefore, the wafer can be cleaned and dried in a clean state without being contaminated by contamination.

  According to a fourth aspect of the present invention, in any one of the first, second, or third aspect, the first supply means supplies the second fluid to the supply member, a tubular member, or a porous member. It is characterized by having a support portion made of a quality material.

  According to a fourth aspect of the present invention, the first supply means includes a support portion to which the supply member is attached, which supplies the second fluid to the supply member. The support portion is formed of a tubular member provided with a slit or a porous material such as PVA sponge, and stores the second fluid therein. The second fluid that exceeds the amount that can be stored inside the support part flows out uniformly from the surface of the support part and is supplied to the supply member.

  As a result, a certain amount of the second fluid is uniformly supplied to the supply member, and the second fluid supplied to the supply member remains in a liquid state near the boundary between the first fluid surface and the wafer surface. To be supplied.

  According to a fifth aspect of the present invention, in any one of the first, second, third, and fourth aspects, the wafer cleaning / drying apparatus supplies a third fluid that prevents oxygen from contacting the wafer surface. The second supply means is provided.

  According to the fifth aspect of the present invention, the third fluid for preventing the oxygen from contacting the wafer surface is supplied from the second supply means in the vicinity of the boundary that is the gas-liquid interface. This makes it possible to quickly retract the gas-liquid interface while preventing the formation of a watermark due to the presence of oxygen.

  A sixth aspect of the invention is characterized in that, in any one of the first, second, third, fourth, and fifth aspects, the third fluid is nitrogen gas.

  According to the invention of claim 6, since the third fluid is nitrogen gas which is an inert gas, it prevents the oxygen from coming into contact with the wafer surface in the vicinity of the boundary line, and forms a watermark by intervening oxygen. Disappears.

  A seventh aspect of the present invention provides the cleaning tank according to any one of the first, second, third, fourth, fifth, or sixth aspect, wherein a supply port that supplies the first fluid to the cleaning tank; It is characterized in that a drain port for discharging one fluid is provided.

  According to the seventh aspect of the present invention, it is possible to supply the first fluid into the cleaning tank and to lift the wafer out of the first fluid without providing a moving mechanism for moving the wafer. It is possible to move the boundary line formed between the first fluid and the wafer in the structure.

  According to an eighth aspect of the present invention, in any one of the first, second, third, fourth, fifth, sixth, and seventh aspects, the wafer cleaning / drying apparatus is filled with the first cleaning tank. A third supply means for supplying the first fluid from the inside of the liquid toward the boundary line is provided.

  According to the invention of claim 8, the first fluid in the vicinity of the boundary line is constantly changed to the first fluid by the new first fluid supplied by the third supply means, while the vicinity of the boundary line. Since a new second fluid is constantly supplied at a constant flow rate, the concentration gradient between the first fluid and the second fluid in the vicinity of the boundary line becomes constant. Therefore, the Marangoni force generated by the difference in surface tension between the two liquids is constantly constant, and stable washing and drying can be performed.

The invention according to claim 9 is a wafer cleaning / drying method for drying a cleaned wafer surface immersed in a cleaning first fluid, the boundary between the wafer surface and the first fluid surface. A supply member that supplies a second fluid having a surface tension smaller than that of the first fluid to the vicinity of the line by capillary action, and the supply member is disposed at a distance at which the second fluid does not form a droplet due to the surface tension. supplies in close proximity to the line, to dry by draining the while maintaining the relative position between the feed member and the boundary line or the wafer is pulled up from the first fluid, or the first fluid It is characterized by that.

  According to the ninth aspect of the present invention, the wafer placed in a tilted manner in the cleaning tank is immersed in the first fluid and cleaned. The wafer after the cleaning is close to the wafer surface in the vicinity of the boundary line between the first fluid surface and the wafer surface formed when the wafer is pulled up from the first fluid or discharged. The second fluid is uniformly supplied in a liquid state from the supply member provided in this manner, and drying is performed.

  Thereby, it becomes possible to supply IPA which is a very small amount of the second fluid having a high concentration near the boundary which is the gas-liquid interface. As a result, an effective concentration gradient is formed between the first fluid and the second fluid, and the wafer is efficiently and uniformly cleaned and dried.

  A tenth aspect of the present invention is the cleaning tank according to the ninth aspect, wherein a new first fluid is supplied toward the boundary line from within the first fluid filled in the cleaning tank. The first fluid is caused to overflow, and the wafer is pulled up from the first fluid to dry the wafer.

  According to the tenth aspect of the present invention, the first newer than the first fluid filled in the cleaning tank is directed toward the boundary between the first fluid surface and the wafer surface formed when the wafer is pulled up. Of fluid is supplied.

  In the vicinity of the boundary line, the first fluid and the second fluid are mixed after partial action, but the mixed liquid portion is continuously pushed by the first fluid supplied toward the boundary line. Diffusing along the vicinity of the surface of the first fluid. The liquid in which the diffused first fluid and second fluid are mixed is discharged from the overflow window provided on the side surface of the cleaning tank.

  Thus, a new first fluid is constantly supplied near the boundary that is the gas-liquid interface, while a new second fluid is constantly supplied near the boundary at a constant flow rate. Therefore, the Marangoni force generated by the difference in surface tension between the two liquids is constantly constant, and stable washing and drying can be performed.

  As described above, according to the wafer cleaning / drying apparatus and wafer cleaning / drying method of the present invention, it becomes possible to continuously supply IPA, which is a very small amount of the second fluid having a high concentration, near the gas-liquid interface. An effective concentration gradient is formed between the first fluid and the second fluid, and the wafer is efficiently and uniformly cleaned and dried. This makes it possible to perform cleaning and drying of a high-quality wafer without generating a watermark without leaving a cleaning solution on the wafer.

  Hereinafter, preferred embodiments of a wafer cleaning / drying apparatus and a wafer cleaning / drying method according to the present invention will be described in detail with reference to the accompanying drawings.

  First, the configuration of a wafer cleaning apparatus according to the present invention and a wafer polishing apparatus incorporating the wafer cleaning / drying apparatus will be described. FIG. 1 is a plan sectional view of a wafer polishing apparatus.

  As shown in FIG. 1, the wafer polishing apparatus 10 includes a cleaning / drying apparatus 1, a wafer storage unit 20, a conveying unit 14, polishing units 16, 16, 16, and a film thickness measuring unit 29.

  The wafer storage unit 20 includes a product wafer storage unit 20A, a dummy wafer storage unit 20B, a first monitor wafer storage unit 20C, and a second monitor wafer storage unit 20D. Each storage unit stores a wafer stored in a cassette 24. W is stored. Two product wafer storage portions 20A are provided side by side. The first monitor wafer storage section 20C uses the lower stage of the cassette 24, and the upper stage of the same cassette 24 is the second monitor wafer storage section 20D.

  The transport means 14 includes an index robot 22, a transfer robot 30, and transport units 36A and 36B.

  The index robot 22 is provided with two arms that can turn and bend freely, and is provided so as to be movable along the arrow Y direction in FIG. The index robot 22 takes out a wafer W to be polished from a cassette 24 placed in each wafer storage unit, transports it to the film thickness measuring means 29 and the delivery ports 26 and 28, and also cleans the wafer W after cleaning. It is received from the cleaning / drying apparatus 1 and stored in the cassette 24.

  The transfer robot 30 includes a load arm 30A and an unload arm 30B that can be bent and swiveled, and is provided so as to be movable along the direction of the arrow X shown in FIG.

  The loading arm 30A is used for transporting the wafer W before polishing, receives the unpolished wafer W from the delivery ports 26 and 28 with a pad (not shown) provided at the tip, and transports the wafer W to the transport units 36A and 36B. .

  The unloading arm 30B is used for transporting the polished wafer W, receives the polished wafer W from the transport units 36A and 36B with a pad (not shown) provided at the tip, and receives the cleaning / drying apparatus 1 or the unload cassette. To 32.

  The transport units 36A and 36B are both movably provided along the arrow Y direction shown in FIG. 1, and move between the receiving positions SA 1 and SB and the delivery positions TA 1 and TB, respectively. The wafer W to be polished is received from the loading arm 30A of the transfer robot 30 at the receiving positions SA and SB, moved to the transfer positions TA and TB, and transferred to the polishing heads 38A and 38B. Further, the polished wafer W is received at the delivery positions TA 1 and TB 2, moved to the reception positions SA 2 and SB 1, and delivered to the unloading arm 30 B of the transfer robot 30.

  Each of the transfer units 36A and 36B has two separate cradles, and these two cradles are used separately for the wafer W before polishing and for the wafer W after polishing.

  The polishing means 16, 16, and 16 polish the wafer W, and as shown in FIG. 1, polishing surface plates 34A, 34B, and 34C, polishing heads 38A and 38B, slurry supply nozzles 37A, 37B, and 37C, and a carrier cleaning unit. 40A and 40B are provided.

  The polishing surface plates 34A, 34B, 34C are formed in a disk shape, and three of them are arranged in parallel. A polishing pad (not shown) is affixed to the upper surface of each polishing surface plate 34A, 34B, 34C, and slurry is supplied from the slurry supply nozzles 37A, 37B, 37C onto the polishing pad. Further, each polishing platen 34A, 34B, 34C is driven and rotated by a motor (not shown), and the wafer W is pressed against the rotating polishing platen 34A, 34B, 34C, whereby the wafer W is polished.

  Here, of the three polishing surface plates 34A, 34B, 34C, the left and right polishing surface plates 34A, 34B are used for polishing the first polishing target film, and the central polishing surface plate 34C is the second polishing target film 34C. Used for polishing. In both types of polishing, the type of slurry to be supplied, the rotation speed of the polishing head and the rotation speed of the polishing surface plate, the pressing force of the polishing head, the material of the polishing pad, and the like are changed.

  Dressing devices 35A, 35B, and 35C are provided in the vicinity of the polishing surface plates 34A, 34B, and 34C, respectively. The dressing devices 35A, 35B, and 35C have a pivotable arm, and dress the polishing pads on the polishing surface plates 34A, 34B, and 34C with a dresser provided at the tip of the arm. Two polishing heads, 38A and 38B, are provided, each being movably provided along the direction of arrow X in FIG.

  The polishing head 38A presses the held wafer W against the polishing pad on the polishing surface plate 34A, and supplies the slurry onto the polishing pad while rotating the polishing surface plate 34A and the polishing head 38A, respectively. Is polished. The polishing head 38B on the other side is similarly configured.

  As shown in FIG. 1, two carrier cleaning units 40A and 40B are installed between the polishing surface plates 34A, 34B and 34C, and are arranged at predetermined delivery positions TA and TB of the transport units 36A and 36B, respectively. Has been. The carrier cleaning units 40A and 40B clean the carriers of the polishing heads 38A and 38B after completion of polishing.

  The film thickness measuring means 29 has a centering mechanism for the wafer W and a film thickness measuring machine. In the film thickness measuring device, when the film to be polished is an oxide film, an optical interference type film thickness measuring machine or the like is used, and when the film to be polished is a metal film, a 4-probe resistivity measuring device or the like Used.

  The cleaning / drying apparatus 1 cleans and dries the wafer W after polishing. The cleaning / drying apparatus 1 is provided with a plurality of cleaning tanks 2, and as shown in FIG. 2, the wafer W is tilted and placed on a moving table 51 as a moving means.

  In the cleaning tank 2, a supply port 3 that supplies a cleaning liquid 50 as a first fluid, a drain port 4 that discharges the cleaning liquid 50 after cleaning, and a first IPA that supplies liquid IPA as a second fluid. A carrier gas supply unit 60 as a second supply unit including an IPA supply unit 6 as a supply unit and a plurality of nozzles 61 for supplying nitrogen as a third fluid for preventing oxygen from contacting the wafer surface. Etc. are provided.

  The cleaning tank 2 is provided with a cleaning mechanism (not shown) such as a double side brush or a pen brush using ultrasonic water. The cleaning mechanism cleans the wafer W immersed in the cleaning solution 50 using an alkaline solution, an acidic chemical solution, deionized water, pure water, or the like supplied from the supply port 3.

  As shown in FIG. 3, the stopper 5 and a plurality of support columns 55 are provided on the movable table 51. One end of the wafer W is supported by the stopper 5, and the back surface is supported by the support pillar 55. The moving table 51 can be moved in the direction of arrow A shown in FIG. 2 by a rail 52 and a driving device (not shown), and pulls up the wafer W immersed in the cleaning liquid 50 from the cleaning liquid 50.

  The IPA supply unit 6 and the carrier gas supply unit 60 are each provided in the block 9. IPA is supplied to the IPA supply unit 6 from a pipe 63 connected to the block 9 through a hole formed in the block 9, and carrier gas is supplied to the carrier gas supply unit 60 from a pipe 62. .

  The block 9 is connected to a moving mechanism (not shown) as moving means. As a result, the IPA supply unit 6 and the carrier gas supply unit 60 can move in parallel while maintaining a constant distance from the wafer W placed in the cleaning tank 2, and the surface of the wafer W and the surface of the cleaning liquid 50 can be moved. A carrier gas such as IPA or nitrogen for drying the wafer W is supplied to the vicinity of the boundary line K.

  The IPA supply unit 6 includes a supply member 7 and a supply pipe 8 as a support unit. The supply member 7 is formed of a linear member made of a polymer resin such as nylon, polyethylene or vinyl acetate formed in a brush shape, or a tubular member made of a polymer resin arranged in a comb shape. Yes. The tip of the supply member 7 is provided close to the surface of the wafer W in the vicinity of the boundary line K up to a distance at which the IPA droplet due to the surface tension of the IPA is not formed at the tip, and the longitudinal direction is parallel to the boundary line K It has been.

  The supply pipe 8 is formed of a tubular member, has a slit formed on the side surface so as to be parallel to the wafer W, is sealed at one end, and is supplied with IPA from the pipe 63. As shown in FIG. 4, the IPA supplied to the supply pipe 8 is stored inside the supply pipe 8 and flows out from the slit 65 when it exceeds a certain amount, and flows down the supply member 7 to cause capillary action or the like. Due to the effect, a very small amount of wafer W is supplied to the surface.

  Further, when the supply member 7 is a tubular member having a minute hole, such as the supply member 7A shown in FIG. 5, the IPA filled in the supply pipe 8A moves in the supply member 7A due to the effect of capillary action. Then, it is supplied to the surface of the very small amount of wafer W.

  Further, the supply member 7 and the supply pipe 8 are provided in the opening of the supply pipe 8B whose upper end is opened at the upper end of the supply member 7B, which is a brush-like member, like the supply member 7B and the supply pipe 8B shown in FIG. When attached, the IPA filled in the supply pipe 8B lifts the supply member 7B, which is a brush-like member, due to the effect of the inter-capillary phenomenon, and is supplied to the surface of the very small amount of wafer W through the supply member 7B.

  With the configuration as described above, the wafer cleaning / drying apparatus according to the present invention can supply a very small amount of IPA having a high concentration near the boundary line K, which is a gas-liquid interface. As a result, an effective concentration gradient is formed, and the wafer W is efficiently and uniformly cleaned and dried.

  In the present embodiment, the supply of IPA to the supply member 7 is performed from the supply pipe 8, and the supply pipe 8 is a tubular member. However, the present embodiment is not limited to this, and the supply pipe 8 is a PVA sponge. Even if it is formed of a porous material such as a brush-like member formed in a linear shape, it can be suitably used due to the effect of the same capillary phenomenon.

  In this case, IPA is stored in the support portion by injecting IPA into the support portion formed of the porous material. The IPA exceeding the amount that can be stored in the support part flows out uniformly from the surface of the support part and is supplied to the supply member 7.

  The specific distance when the supply member 7 is close to the surface where the IPA droplet is not formed at the tip of the wafer W surface can be calculated by the following method. As an example, a water droplet falling from a circular tube having an outer diameter of 5 mm is assumed. At a temperature of 20 degrees, the surface tension of water is 72.8 mN / m. If the outer diameter is 5 mm, the outer peripheral length is about 15.7 mm. Since the surface tension of 72.8 mN / m acts on a length of 15.7 mm, the stress supporting one water droplet against gravity is 1.14 mN. Here, since the gravitational acceleration is 9.8 m / s 2, the weight of the supported water droplet is 0.117 g. Since this corresponds to a volume of 117 mm2, the radius is calculated to be about 3 mm. Therefore, the outer diameter of a water droplet dripped from a circular tube having an outer diameter of 5 mm is 6 mm in diameter. As a result, the radius of the water droplet is about 3 mm to 4 mm from the lower surface of the circular tube having an outer diameter of 5 mm to the lower surface of the droplet. In the case where IPA is replaced with water, the proximity distance in the present invention means that it is within a position of about 3 mm to 4 mm from the surface of the wafer W. Similarly, in the case of IPA, by determining the surface tension, it is possible to calculate the approach distance from the radius supporting the droplet.

  Next, an apparatus configuration in another embodiment of the wafer cleaning / drying apparatus according to the present invention will be described. The cleaning / drying apparatus 70 provided in the wafer polishing apparatus 10 shown in FIG. 1 is provided with a plurality of cleaning tanks 71, and as shown in FIG. 6, the wafer W tilts on a moving table 51 as a moving means. Placed.

  The cleaning tank 71 is provided with a supply port 3 for supplying a cleaning liquid 50 as a first fluid and a drain port 4 for discharging the used cleaning liquid 50 on the bottom surface. When the wafer W is dried, the cleaning liquid 50 and the IPA are provided. A window 76 through which the liquid mixed with is discharged is provided on the side surface.

  Further, in the cleaning tank 71, an IPA supply unit 6 that supplies liquid IPA, a carrier gas supply unit 60 that includes a plurality of nozzles 61 that supply nitrogen, and a plurality that supplies the cleaning liquid 50 toward the boundary line K. A cleaning liquid supply unit 73 as a third supply unit including the nozzle 74 is provided.

  The cleaning tank 71 is provided with a cleaning mechanism (not shown) such as a double side brush or a pen brush using ultrasonic water. The cleaning mechanism cleans the wafer W immersed in the cleaning solution 50 using an alkaline solution, an acidic chemical solution, deionized water, pure water, or the like supplied from the supply port 3.

  As shown in FIG. 7, the stopper 5 and a plurality of support columns 55 are provided on the movable table 51. One end of the wafer W is supported by the stopper 5, and the back surface is supported by the support pillar 55. The moving table 51 is movable in the direction of arrow A shown in FIG. 6 by the rail 52 and a driving device (not shown), and pulls up the wafer W immersed in the cleaning liquid 50 from the cleaning liquid 50.

  The IPA supply unit 6, the carrier gas supply unit 60, and the cleaning liquid supply unit 73 are provided in the block 72, respectively. IPA is supplied to the IPA supply unit 6 from a pipe 63 connected to the block 72 through a hole formed in the block 72, and carrier gas is supplied to the carrier gas supply unit 60 from a pipe 62. .

  The cleaning liquid supply unit 73 is located in the cleaning liquid 50 filled in the cleaning tank 71, and is provided in the block 72 with the nozzle 74 facing the boundary line K. The cleaning liquid 50 is supplied to the cleaning liquid supply unit 73 through a hole formed in the block 72 from the pipe 75, and the supplied cleaning liquid 50 is jetted toward the boundary line K.

  The sprayed cleaning liquid 50 forms a large concentration gradient with the IPA supplied from the IPA supply unit 6, and part of the IPA melts into the cleaning liquid 50. The molten IPA diffuses along the vicinity of the surface of the cleaning liquid 50 filled in the cleaning tank 71 and is discharged out of the apparatus through the window 76. Thereby, a new cleaning liquid 50 is always supplied to the vicinity of the boundary line K.

  The IPA supply unit 6 includes a supply member 7 and a supply pipe 8 as a support unit. The distal end portion of the supply member 7 is close to the boundary K to a distance at which the IPA droplet is not formed at the distal end portion due to the surface tension of the IPA. It is close to the surface of the wafer W.

  As shown in FIG. 4, the supply pipe 8 has slits formed on the side surfaces so as to be parallel to the wafer W, and when the supplied IPA is stored inside the supply pipe 8 and exceeds a certain amount. The liquid flows out of the slit 65, flows down the supply member 7, and is supplied to the surface of the wafer W.

  Further, when the supply member 7 is a tubular member having a minute hole, such as the supply member 7A shown in FIG. 5, the IPA filled in the supply pipe 8A moves in the supply member 7A due to the effect of capillary action. And supplied to the surface of the wafer W.

  With the configuration as described above, in another embodiment of the wafer cleaning / drying apparatus according to the present invention, a very small amount of IPA having a high concentration is supplied in the vicinity of the boundary line K, which is the gas-liquid interface, and A new cleaning liquid 50 is always supplied near the line K at a constant flow rate. Thereby, a concentration gradient between the IPA near the boundary line and the cleaning liquid is formed to be constant, and stable and uniform drying can be performed.

  Next, the wafer cleaning / drying method according to the present invention will be described. As shown in FIG. 2, the wafer W polished by the wafer polishing apparatus 10 shown in FIG. 1 is tilted and placed on a movable table 51 provided in the cleaning tank 2 of the cleaning / drying apparatus 1. After the wafer W is placed, the cleaning liquid 50 is supplied from the supply port 3, and the wafer W immersed in the cleaning liquid 50 is cleaned by a cleaning mechanism (not shown).

  After completion of the cleaning, the tip of the supply member 7 of the IPA supply unit 6 is brought close to the uppermost surface of the wafer W immersed in the cleaning solution 50 by a moving means (not shown). In this state, the cleaning liquid 50 is discharged from the drain port 4. Accordingly, IPA for drying the wafer W is supplied from the supply pipe 8 to the supply member 7, and the carrier gas is injected from the nozzle 61 of the carrier gas supply unit 60. .

  When the cleaning liquid 50 is discharged and the liquid level of the cleaning liquid 50 decreases, a boundary line K between the surface of the wafer W and the surface of the cleaning liquid 50 is formed on the surface of the wafer W and moves along with the decrease in the liquid level.

  The IPA supply unit 6 and the carrier gas supply unit 60 move in accordance with the movement of the boundary line K. The supply member 7 of the IPA supply unit 6 has a tip portion close to the surface of the wafer W near the boundary K, and the distance between the supply member 7 and the wafer W is kept constant, as shown in FIG. Move to position C.

  Similarly to the IPA supply unit 6, the carrier gas supply unit 60 also moves to the arrow B position and the arrow C position so as to supply the carrier gas near the boundary line K.

  At this time, near the boundary line K, as shown in FIG. 8, the capillary phenomenon that occurs due to the interfacial tension between the supply member 7 and the surface of the wafer W caused by the IPA flowing in a small amount through the supply member 7 due to the capillary phenomenon. As a result, a small concentration is continuously supplied, and a large concentration gradient is formed at the interface between the cleaning liquid 50 and the IPA.

  Thereby, the Marangoni force due to the Marangoni effect is effectively generated between the cleaning liquid and the IPA without variation, and uniform drying is performed on the entire surface of the wafer W.

  The dried wafer W is unloaded from the cleaning tank 2 by the index robot 22 or the transfer robot 30.

  Next, another embodiment of the wafer cleaning / drying method according to the present invention will be described. As shown in FIG. 7, the wafer W polished by the wafer polishing apparatus 10 shown in FIG. 1 is tilted and placed on the moving table 51 provided in the cleaning tank 71 of the cleaning / drying apparatus 70. After the wafer W is placed, the cleaning liquid 50 is supplied from the supply port 3, and the wafer W immersed in the cleaning liquid 50 is cleaned by a cleaning mechanism (not shown).

  After completion of the cleaning, as shown in FIG. 8, the tip of the supply member 7 of the IPA supply unit 6 is brought close to the uppermost surface of the wafer W immersed in the cleaning solution 50 by a moving means (not shown). In this state, the movable table 51 rises in the direction of arrow A1 in FIG. 8 and the wafer W is pulled up from the cleaning liquid 50.

  Accordingly, the IPA for drying the wafer W from the IPA supply unit 6 is continuously supplied in a trace amount by the effect of capillary action or the like caused by the interfacial tension acting between the supply member 7 and the surface of the wafer W, and the carrier gas Is injected from the nozzle 61 of the carrier gas supply unit 60. Furthermore, a new cleaning liquid 50 is jetted in the direction of arrow F1 from the cleaning liquid supply unit 73 located inside the cleaning liquid 50 toward the vicinity of the boundary line K formed on the wafer W surface when the wafer W is pulled up. The

  The sprayed cleaning liquid 50 forms a large concentration gradient with a small amount of IPA supplied from the IPA supply unit 6 at the boundary K, and a part of the IPA melts into the cleaning liquid 50.

  The IPA melted in the cleaning liquid 50 diffuses along the vicinity of the surface of the cleaning liquid 50 filled in the cleaning tank 71 as indicated by an arrow F2 shown in FIG. 8, and is discharged out of the apparatus from the window 76 as indicated by an arrow F3. Is done.

  As a result, a new cleaning solution 50 is always supplied to the vicinity of the boundary line K, a concentration gradient between the IPA and the cleaning solution 50 in the vicinity of the boundary line K is formed constant, and stable and uniform drying can be performed. Become.

  The dried wafer W is unloaded from the cleaning tank 71 by the index robot 22 or the transfer robot 30.

  Next, experimental examples by the wafer cleaning / drying method according to the present invention will be shown. As the wafer cleaning / drying method, the wafer cleaning / drying method according to the method described in another embodiment is used, and the configuration of the experimental apparatus is the same as that of the wafer cleaning / drying apparatus shown in FIG.

  The conditions of the experiment are as shown in FIG. 10. Ultrapure water is used as washing water as the first fluid, IPA having a concentration of 50% is used as the second fluid, and purity is 99.99% or more as the third fluid. Nitrogen gas is used.

  As a result of this experiment, the number of defects on the wafer surface was 22 (> 0.18 μm, including scratches and particles). Watermark and streak lines were not confirmed. Thus, it was confirmed that in the wafer cleaning / drying method according to the present invention, it is possible to perform cleaning / drying of a high-quality wafer without generating a watermark without leaving a cleaning solution on the wafer.

  As described above, according to the wafer cleaning / drying apparatus and the wafer cleaning / drying method according to the present invention, the IPA that is the second fluid having a very small concentration and the cleaning liquid that is the first fluid are supplied to the gas-liquid interface. It becomes possible to supply to the vicinity uniformly and continuously. A high concentration gradient is formed between the supplied IPA and the cleaning liquid, and the wafer is uniformly cleaned and dried. This makes it possible to perform cleaning and drying of a high-quality wafer without generating a watermark without leaving a cleaning solution on the wafer.

  In the present embodiment, the wafer cleaning / drying apparatus 1 according to the present invention is described as being incorporated in the wafer polishing apparatus 10, but it is preferable that only the wafer cleaning / drying apparatus 1 is used as another apparatus. Is available.

1 is an overall configuration diagram of a wafer polishing apparatus according to the present invention. The perspective view which showed the structure of the wafer washing | cleaning drying apparatus. Side surface sectional drawing which showed the structure of the wafer washing | cleaning drying apparatus. Side surface sectional drawing of an IPA supply part. Side surface sectional drawing of another IPA supply part. Side surface sectional drawing of another IPA supply part. The perspective view which showed the structure of another wafer washing | cleaning drying apparatus. Side surface sectional drawing which showed the structure of another wafer washing | cleaning drying apparatus. Sectional drawing explaining the drying method of a wafer. The chart which showed the conditions of implementation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,70 ... Wafer cleaning drying apparatus, 2, 71 ... Cleaning tank, 3 ... Supply port, 4 ... Drain port, 5 ... Stopper, 6 ... IPA supply part (1st supply means), 7 ... Supply member, 8 ... Supply pipe (support part), 9, 72 ... Block, 10 ... Wafer polishing apparatus, 50 ... Cleaning liquid (first fluid), 51 ... Moving platform, 52 ... Rail, 55 ... Support column, 60 ... Carrier gas supply part ( (Second supply means), 61... Nozzle, 73... Cleaning liquid supply section (third supply means), K.

Claims (10)

A cleaning tank that is filled with a first fluid for cleaning and in which a wafer immersed in the first fluid is cleaned;
When pulling up the wafer from the first fluid or discharging the first fluid, the surface tension is higher than that of the first fluid in the vicinity of the boundary line between the first fluid surface and the wafer surface. First supply means for supplying a small second fluid for drying the wafer by capillary action;
And said wafer and said first supply means are relatively moved, a moving means for the first supply means to distance the second fluid does not form droplets by surface tension Ru is close to the boundary line A wafer cleaning / drying apparatus comprising:   The first supply means includes a supply member formed of a linear member or a tubular member, and a tip of the supply member is close to the wafer surface in the vicinity of the boundary line. 2. The wafer cleaning / drying apparatus according to 1.   The wafer cleaning / drying apparatus according to claim 1, wherein the supply member is made of a polymer resin material.   The said 1st supply means is equipped with the support part formed with the tubular member or the porous material which supplies the said 2nd fluid to the said supply member, The Claim 1, 2, or characterized by the above-mentioned. 3. The wafer cleaning / drying apparatus according to any one of 3 above.   5. The wafer cleaning / drying apparatus is provided with a second supply means for supplying a third fluid for preventing contact of oxygen with the wafer surface. The wafer cleaning / drying apparatus according to any one of the above.   The wafer cleaning / drying apparatus according to claim 5, wherein the third fluid is nitrogen gas.   The said washing tank is provided with the supply port which supplies said 1st fluid, and the drain port which discharges | emits said 1st fluid, The 1, 2, 3, 4, 5, Or the wafer cleaning / drying apparatus according to any one of 6 above.   The wafer cleaning / drying apparatus is provided with third supply means for supplying the first fluid from the inside of the first liquid filled in the cleaning tank toward the boundary line. The wafer cleaning / drying apparatus according to any one of claims 1, 2, 3, 4, 5, 6, and 7. A wafer cleaning / drying method for drying a cleaned wafer surface immersed in a first fluid for cleaning,
A supply member for supplying a second fluid having a surface tension smaller than that of the first fluid to the vicinity of a boundary line between the wafer surface and the first fluid surface by capillary action, and the second fluid by surface tension. Supplying the supply member close to the boundary line at a distance where droplets are not formed, and lifting the wafer from the first fluid while maintaining a relative position between the supply member and the boundary line, or A wafer cleaning and drying method, wherein drying is performed by discharging the first fluid.   A new first fluid is supplied from the first fluid filled in the cleaning tank toward the boundary line to overflow the first fluid from the cleaning tank, and the wafer is moved to the first fluid. The wafer cleaning and drying method according to claim 9, wherein the wafer is dried by pulling up from the fluid of 1.

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