JP2007266210A - Apparatus and method for manufacturing semiconductor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor manufacturing apparatus and a semiconductor manufacturing method capable of reducing foreign matters that adhere to a semiconductor substrate. <P>SOLUTION: A wafer cleaning apparatus 10 as a constituent of the semiconductor manufacturing apparatus 1 is provided with a cleaning bath 12 for treating wafers W with a predetermined chemical; a centrifuge 18 for separating a gel-like substance contained in the chemical from the chemical to be supplied to the cleaning bath 12; and a filter device 20 for removing particles, contained in the chemical to be supplied from the centrifuge 18 to the cleaning bath 12, after the gel-like substance has been removed by the centrifuge 18. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor manufacturing apparatus and a semiconductor manufacturing method used for liquid processing of a semiconductor substrate with a predetermined processing liquid, in particular, cleaning processing of a semiconductor substrate using a chemical solution.

  In a semiconductor device manufacturing process, if foreign matter such as particles or metal adheres to a semiconductor substrate (hereinafter referred to as “wafer”), the production yield decreases, and this yield decrease becomes more prominent as the design rule becomes finer. Therefore, in general, in the manufacturing process of a semiconductor device, in order to remove foreign matters attached to the wafer, for example, metal, particle contamination, organic matter, etc., a cleaning process for removing these using a chemical solution is provided.

  As one of the wafer cleaning methods, a plurality of wafers are simultaneously immersed in a chemical solution stored in a processing tank and held for a certain period of time, while a part of the chemical liquid in the processing tank is discharged at a constant flow rate. A so-called batch / circulation type cleaning method is known in which a chemical solution is circulated and used so that foreign matters such as particles are removed from a filter by a filter and then returned to a treatment tank.

  However, since it is difficult to completely remove the foreign matter in the chemical solution using the filter, the processing of the wafer is completed when the amount of the foreign matter reaches a predetermined constant value while monitoring the amount of the foreign matter in the chemical solution. All chemical solutions are replaced with new chemical solutions (see, for example, Patent Document 1).

  In removing foreign matters using such a filter, the number of foreign matters attached to the wafer can be clearly reduced by using a filter having a small pore diameter. However, despite the fact that the amount of foreign matter to be monitored has not reached the predetermined value, there is a problem that foreign matter larger than the pore diameter of the filter adheres to the wafer, which affects the production yield. Such a problem is particularly likely to occur when cleaning a wafer in which organic matter remains, such as after dry etching using a resist mask.

One cause of this is the generation of a gel-like substance in the cleaning process. That is, even if the foreign matter adhering to the wafer is detached from the wafer by immersing the wafer in the chemical solution, the foreign matter may not be completely dissolved by the chemical solution and become a gel-like foreign matter. Since such a gel-like foreign material is freely deformable, it passes through the filter and floats in the chemical solution. When multiple batches of wafers are sequentially processed, the amount of gel-like substances in such chemicals increases with each process. In FIG. 3, a plurality of gel substances are bonded to each other to form a large gel substance and reattach to the wafer. Thus, the gel-like substance adhering to the wafer appears as foreign matter (contamination) after rinsing with pure water (DIW) after chemical treatment and further drying.
JP 2004-356356 A (FIG. 1, paragraphs [0018] to [0021] etc.)

  An object of this invention is to provide the semiconductor manufacturing apparatus and semiconductor manufacturing method which can reduce the foreign material adhering to a semiconductor substrate.

  According to the first aspect of the present invention, a liquid processing unit that performs liquid processing on a semiconductor substrate with a predetermined processing liquid, and a gel-like substance contained in the processing liquid is separated from the processing liquid that is supplied to the liquid processing unit. And a filter for removing particles contained in the processing liquid from the processing liquid supplied from the centrifugal separator to the liquid processing unit after the gel-like substance is removed by the centrifugal separator. A semiconductor manufacturing apparatus is provided.

  According to the second aspect of the present invention, a gel-like substance contained in a treatment liquid for liquid-treating a semiconductor substrate is separated from the treatment liquid by a centrifugal separation method, and the gel-like substance is separated by the centrifugal separation method. There is provided a semiconductor manufacturing method characterized in that particles contained in a treated liquid after the removal are removed from the treated liquid by a filter, and the treated liquid after the particles are removed by the filter is used for a liquid treatment of a semiconductor substrate. The

  According to the present invention, the gel-like substance that passes through the pores of the filter can be removed by the centrifuge, so that the number of foreign matters adhering to the semiconductor substrate can be reduced. Thus, production yield can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic configuration of a batch / circulation type wafer cleaning apparatus used for manufacturing a semiconductor device.

  The wafer cleaning apparatus 10 includes a cleaning tank 12 for cleaning the wafer W, a recovery tank 14 for recovering the chemical liquid discharged from the cleaning layer 12, and a centrifugal separation process for performing a centrifugal separation process of the chemical liquid supplied from the recovery tank. 18, a filter device 20 that filters the chemical solution that has been subjected to the centrifugal separation process by the centrifuge 18, and a liquid feed pump that sends the chemical solution from the recovery tank 14 to the cleaning tank 12 through the centrifugal separator 18 and the filter device 20. 16 and these constitute a chemical solution circulation system. The wafer cleaning apparatus 10 also has a new liquid supply unit 22 for supplying a new liquid to the chemical liquid circulation system.

  Although not shown, the wafer cleaning apparatus 10 further has a container loading / unloading section for loading / unloading a container containing a predetermined number of wafers W, and a wafer placed on the container loading / unloading section. The wafer W is loaded / unloaded, the horizontal / vertical posture of the wafer W is changed as necessary, and transferred to the cleaning tank 12 or the like, and the wafer W that has been cleaned by the cleaning tank 12 is treated with pure water ( A rinsing unit for rinsing with DIW) and a drying unit for drying the rinsed wafer W.

  The cleaning tank 12 stores a predetermined amount of cleaning chemical solution and cleans the wafer W by simultaneously immersing a plurality of wafers W in the chemical solution for a predetermined time. The wafer cleaning apparatus 10 may have a structure having a plurality of cleaning tanks 12 in order to continuously perform cleaning processes using different chemical solutions. In that case, a chemical solution circulation system is configured for each cleaning tank.

  A chemical liquid at a constant flow rate is supplied from the filter device 20 to the cleaning tank 12, and the chemical liquid in the cleaning tank 12 flows out of the cleaning tank 12 at a constant flow rate due to overflow or the like and is collected in the recovery tank 14. In the chemical solution flowing out from the cleaning tank 12 in this manner, solid substances such as particles detached from the wafer W and gel-like substances not completely dissolved by the chemical solution are mixed as foreign substances.

  As the chemical solution, a suitable one is appropriately selected depending on the purpose of cleaning the wafer W. For example, a mixed aqueous solution of hydrochloric acid and hydrogen peroxide for the purpose of removing metal contaminants, ammonia and hydrogen peroxide for the purpose of removing particles. A mixed aqueous solution of water, a mixed solution of sulfuric acid and hydrogen peroxide solution for the purpose of removing organic contamination, a hydrofluoric acid aqueous solution for the purpose of removing a natural oxide film, or the like is used.

  In the wafer cleaning apparatus 10, the new liquid supply unit 22 is provided so as to supply the above-described new liquids of various chemical liquids to the recovery tank 14. The new liquid supply unit 22 not only supplies the chemical liquid whose composition has been adjusted to the recovery tank 14 to ensure the amount of chemical liquid necessary for the wafer W cleaning process, but the chemical liquid is a mixed liquid of a plurality of types of aqueous solutions. In this case, various aqueous solutions and pure water (DIW) can be supplied independently in order to adjust the composition of the chemical solution circulating in the wafer cleaning apparatus 10.

  In addition, by supplying the new liquid to the recovery tank 14, the circulating water and the new liquid can be mixed in the recovery tank 14.

  The chemical solution in the collection tank 14 is continuously sent to the centrifuge 18 by the liquid feed pump 16. Thereby, the inside of the centrifugal separator 18 is filled with the chemical solution, and the chemical solution is further fed from there to the cleaning tank 12 through the filter device 20. Thus, as described above, when the chemical solution is supplied to the cleaning tank 12, the chemical solution overflows from the cleaning tank 12 and is collected in the collection tank 14. Such a flow of the chemical liquid continues while the liquid feed pump 16 is operating.

  FIG. 2 shows a schematic structure of the centrifuge 18. The centrifuge 18 has a novel structure that is particularly preferably applied to the wafer cleaning apparatus 10, and includes a double drum 30 including an inner drum 32 and an outer drum 34 surrounding the inner drum 32, and a double drum 30. A housing (housing) 36 and a motor 38 for rotating the double drum 30. The axis of the inner drum 32 and the axis of the outer drum 34 coincide with each other at the pivot 30a, and the centrifuge 18 is preferably installed so that the pivot 30a is vertical. The inner drum 32 and the outer drum 34 rotate integrally around the pivot 30a.

  The inner drum 32 and the outer drum 34 have pores 32b and 34b, respectively, and the chemical solution can move through these pores 32b and 34b. In order to supply the chemical solution fed from the recovery tank 14 from the lower end of the double drum 30 between the inner drum 32 and the outer drum 34, a chemical solution supply port 34 a is provided at the lower end of the outer drum 34. Further, in order to discharge the chemical solution in the inner drum 32 from the upper end thereof, a chemical solution intake port 32a is provided at the upper end of the inner drum 32, and the chemical solution flowing out from the chemical solution intake port 32a is sent to the filter device 20. The The casing 36 is provided with a waste liquid discharge port 36 a for discharging the chemical liquid between the outer drum 34 and the casing 36.

  When the chemical solution is circulated by the operation of the liquid feeding pump 16, the inside of the centrifugal separator 18 is maintained in a state filled with the chemical solution through the pores 34b of the inner drum 32 and the outer drum 34.

  When the double drum 30 is rotated by driving the motor 38 in this state, a centrifugal force acts on the chemical solution supplied between the inner drum 32 and the outer drum 34 by the liquid feeding pump 16, and the foreign matter having a large specific gravity. Is contained, the foreign matter passes through the hole 34b of the outer drum 34 and moves to the outside of the outer drum 34. Here, the foreign substances moving to the outside of the outer drum 34 are solids such as particles or gel-like substances as described above.

  On the other hand, since the chemical liquid is continuously fed into the space between the inner drum 32 and the outer drum 34 by the liquid feeding pump 16, the pressure between the inner drum 32 and the outer drum 34 is increased. A chemical solution free of foreign matter having a large specific gravity passes through the hole 32b into the inner drum 32 and is fed to the filter device 20 through the chemical solution intake port 32a.

  In this way, in the chemical solution existing between the outer drum 34 and the casing 36, the foreign matter concentration gradually increases, and is discharged from the waste liquid discharge port 36a to the outside (for example, a waste liquid recovery tank) at a constant flow rate, for example.

  In order to separate such foreign substances in the chemical solution, the diameter of the pores 32b formed in the inner drum 32 can be 1 to 10 μm, while the diameter of the pores 34b formed in the outer drum 34 is 10 μm. It is preferable to be set to ˜100 μm. As a result, the gel-like substance or large solid contained in the chemical solution is difficult to pass through the pores 32b formed in the inner drum 32 and easily passes through the pores 34b formed in the outer drum 34.

  Thus, since the centrifuge 18 can remove the gel-like substance that cannot be removed by the filter device 20, the foreign substance adhering to the wafer W can be suppressed by suppressing the re-attachment of the gel-like substance to the wafer W. The number can be reduced.

  The wafer cleaning apparatus 10 has a structure in which the new liquid is supplied to the recovery tank 14 so that the centrifuge 18 can remove the gel-like substance even if the new liquid contains a gel substance.

  In addition, since the centrifuge 18 can separate relatively large particles present in the chemical liquid from the chemical liquid fed to the filter device 20, clogging of the filter provided in the filter device 20 is suppressed, and the filter You will be able to extend your life.

  The chemical solution from which the gel substance has been removed in the centrifuge 18 is sent to the filter device 20. The filter device 20 includes a particle capturing filter (not shown), and a filter having a pore size of 0.1 μm or less is preferably used. In the filter device 20, solids larger than the filter pore diameter are captured. In this way, the chemical solution containing very little gel substance and particles is supplied from the filter device 20 to the cleaning tank 12. By performing such chemical solution circulation, the life of the chemical solution can be extended.

  When the temperature of the chemical solution is adjusted in the wafer cleaning apparatus 10, a heater is provided between the cleaning tank 12 and the recovery tank 14, between the centrifuge 18 and the filter apparatus 20, between the filter apparatus 20 and the cleaning tank 12, and the like. Can be provided.

  The wafer W processed in the cleaning tank 12 for a predetermined time as described above is subsequently transferred to the rinsing processing unit, where it is rinsed, and if necessary, processing with another chemical solution and subsequent rinsing processing are appropriately performed. Then, it is transported from the rinse processing unit to the drying processing unit where it is dried and then returned to the container. And this container is carried out to the apparatus for performing the next semiconductor manufacturing process.

  The centrifuge used in the wafer cleaning apparatus 10 described above is not limited to the one shown in FIG. 2, and a known centrifuge can also be used. FIG. 3 shows a schematic structure of another centrifuge that can be used in the wafer cleaning apparatus 10. The centrifugal separator 18A has substantially the same structure as a centrifugal liquid separator (V-5 type, V-10 type, etc.) manufactured by CICN, USA.

  The centrifuge 18A includes a non-liquid-permeable drum 42 that is arranged with its axis vertically, a motor 44 that rotates the drum 42 around the axis, and a casing 46 that rotatably accommodates the drum 42. is doing.

  The bottom wall of the drum 42 is provided with a chemical solution supply port 42 a for taking in the chemical solution supplied from the recovery tank 14. Therefore, the chemical solution supply port 46 a for introducing the chemical solution supplied from the recovery tank 14 into the casing 46 is provided on the side surface or the bottom surface of the casing 46.

  When the chemical liquid is supplied into the drum 42 from the chemical liquid supply port 42a while rotating the drum 42, the chemical liquid rises along the inner surface of the drum 42 by centrifugal force, while particles and gel-like substances contained in the chemical liquid are centrifugal force. It moves to the vicinity of the inner surface of the drum 42 and is concentrated. Therefore, a waste liquid discharge port 42b is provided at the outer edge of the upper end of the drum 42, from which a chemical liquid in which a gel substance or the like is concentrated is discharged as a waste liquid.

  On the other hand, the chemical liquid from which the gel-like substance is removed from the chemical liquid that rises along the inner surface of the drum 42 by the centrifugal force when the drum 42 is rotated is provided with a chemical liquid inlet 42 c at the center of the upper end of the drum 42. Can be taken out from here and sent to the filter device 20.

  When this centrifuge 18A is used, the wafer cleaning device 10 uses (A) the centrifuge 18A and the filter to send the chemical solution with a small amount of foreign matter discharged from the centrifuge 18A to the filter device 20. A configuration in which a liquid feed pump is further provided between the apparatus 20 and (B) a centrifuge 18A is disposed between the washing tank 12 and the recovery tank 14 to centrifuge the chemical solution discharged from the washing tank 12. The chemical liquid that has been processed in the vessel 18A and thus removed from the gel substance is collected in the collection tank 14, and is fed from there to the filter device 20 by the liquid feed pump 16.

  However, in the configuration of (A), there is a problem that the flow rate is not stable unless the amount of the chemical liquid discharged from the centrifuge 18A and the suction flow rate of the liquid feeding pump are balanced, so this point needs to be noted. . In the configuration (B), since the chemical solution is temporarily stored in the recovery tank 14, there is a possibility that a new gel-like substance is generated in the recovery tank 14. Since such a problem does not occur when the centrifuge 18 shown in FIG. 2 is used, the configuration of the wafer cleaning apparatus using the centrifuge 18 can be said to be the best configuration.

  Next, a single wafer / one-pass type wafer processing apparatus will be described. FIG. 4 shows a schematic configuration of this wafer processing apparatus. The wafer processing apparatus 50 includes a chemical solution supply unit 52, a wafer processing unit 54, and a chemical solution recovery tank 56.

  The chemical solution supply unit 52 includes a chemical solution tank 62 in which the chemical solution is stored, a liquid feed pump 64 for sending the chemical solution in the chemical solution tank 62 to the wafer processing unit 54, the centrifuge 18, and the filter device 20. . The centrifuge 18 and the filter device 20 are the same as those used in the wafer cleaning device 10.

  In the wafer processing unit 54, the wafers W are processed one by one. Therefore, the wafer processing unit 54 includes a rotatable spin chuck 66 that holds the wafer W, a cup 68 that is provided so as to surround the wafer W held by the spin chuck 66, and a chemical solution that is used to discharge a chemical to the wafer W. A discharge nozzle 70 is provided, and a drainage port 68 a for discharging the used chemical liquid to the waste liquid recovery tank 56 is provided below the cup 68. When temperature control of the chemical solution discharged from the discharge nozzle 70 is necessary, for example, the temperature of the chemical solution may be adjusted by a heater while the chemical solution is sent from the filter device 20 to the discharge nozzle 70.

  In the one-pass method, the chemical solution used for the processing of the wafer W is discarded without being recycled. However, depending on the chemical solution, the chemical solution is concentrated by evaporation of the solvent or temporarily stored in the atmosphere during temporary storage in the chemical solution tank 62. Touching may cause the component to oxidize or a chemical reaction such as a polymerization reaction between the components may occur, and a gel-like substance may be generated and increased in the chemical solution. Such a change with time of the chemical solution is likely to occur particularly in an organic chemical solution containing an organic solvent. Such organic chemical solutions include various chemical solutions for forming a coating film such as a resist solution.

  Therefore, the centrifuge 18 is provided between the chemical liquid tank 62 and the discharge nozzle 70 to remove the gel-like substance generated in the chemical liquid, and further, the particles are removed by the filter device 20 to thereby form a gel on the wafer W. Adhesion of substances and the like can be suppressed.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, it can deform | transform and implement variously.

  For example, the batch / circulation type wafer cleaning apparatus 10 holds a plurality of wafers W in a rotor, accommodates them in a chamber, supplies chemicals to the wafers W while rotating the rotor, and processes the wafers W with chemicals. The thing of the structure to perform may be sufficient. That is, there is no limitation on the processing mode of the wafer W.

  Further, by replacing the part of the cleaning tank 12 in the batch / circulation type wafer cleaning apparatus 10 and the part of the wafer processing unit 54 in the single wafer / one-pass type wafer processing apparatus 50, these can be replaced with a single wafer / circulation type. The wafer processing apparatus and the batch one-pass wafer processing apparatus can be modified. The single wafer / circulation type wafer processing apparatus can be suitably used for, for example, a scrub cleaning process or a development process of a resist film after exposure.

  Further, in the wafer cleaning apparatus 10, the new liquid is supplied to the recovery tank 14. However, the new liquid may be supplied to the cleaning tank 12, and in that case, a gel substance is generated in the new liquid. In such a case, it is preferable to provide a centrifuge and a filter device in the new liquid supply line.

1 is a schematic configuration diagram of a batch / circulation type wafer cleaning apparatus according to an embodiment of the present invention. FIG. Sectional drawing which shows schematic structure of the centrifuge suitably used for the wafer cleaning apparatus of FIG. Sectional drawing which shows schematic structure of another centrifuge which can be used for the wafer cleaning apparatus of FIG. The schematic block diagram of the wafer processing apparatus of the single wafer and one pass type which is another embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Wafer cleaning apparatus, 12 ... Cleaning tank, 14 ... Collection tank, 16 ... Liquid feed pump, 18 * 18A ... Centrifugal separator, 20 ... Filter apparatus, 22 ... New liquid supply part, 30 ... Double drum, 30a ... Pivot axis, 32 ... inner drum, 32a ... chemical intake port, 32b ... fine hole, 34 ... outer drum, 34a ... chemical solution supply port, 34b ... fine hole, 36 ... casing, 36a ... waste liquid discharge port, 38 ... motor, 42 ... Drum, 42a ... chemical solution supply port, 42b ... waste solution discharge port, 42c ... chemical solution intake port, 44 ... motor, 46 ... casing, 46a ... chemical solution supply port, 50 ... wafer processing apparatus, 52 ... chemical solution supply unit, 54 ... wafer Processing part 56 ... Chemical solution recovery tank 62 ... Chemical solution tank 64 ... Liquid feed pump 66 ... Spin chuck 68 ... Cup 68a ... Drain port 70 ... Discharge nozzle

Claims (5)

A liquid processing unit for liquid processing a semiconductor substrate with a predetermined processing liquid;
A centrifuge for separating a gel substance contained in the treatment liquid from the treatment liquid supplied to the liquid treatment unit;
And a filter for removing particles contained in the treatment liquid from the treatment liquid supplied from the centrifugal separator to the liquid treatment unit after the gel substance is removed by the centrifugal separator. Semiconductor manufacturing equipment.   The semiconductor manufacturing apparatus according to claim 1, further comprising a processing liquid circulating means for discharging a part of the processing liquid from the liquid processing section and feeding the processed liquid to the centrifuge. The centrifuge is
A double drum comprising an inner drum having pores for allowing the treatment liquid to pass therethrough and an outer drum surrounding the inner drum;
A casing for housing the double drum;
A motor for rotating the double drum;
A treatment liquid supply port provided in the outer drum for supplying the treatment liquid between the inner drum and the outer drum;
A treatment liquid intake port provided in the inner drum for discharging the treatment liquid in the inner drum;
A waste liquid discharge port provided in the casing for discharging the processing liquid between the outer drum and the casing;
The semiconductor manufacturing apparatus according to claim 1, wherein the processing liquid discharged from the processing liquid intake port is sent to the filter. Separating the gel-like substance contained in the treatment liquid for liquid treatment of the semiconductor substrate from the treatment liquid by centrifugation,
Removing particles contained in the treatment liquid after the gel-like substance has been separated by the centrifugal separation method from the treatment liquid,
A semiconductor manufacturing method, wherein a processing liquid after particles are removed by the filter is used for liquid processing of a semiconductor substrate.   While processing a semiconductor substrate with a processing solution, a part of the processing solution used therein is discharged, and the gel-like substance contained in the processing solution is separated from the processing solution by the centrifugal separation method. The semiconductor manufacturing method according to claim 4.

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