JP2013033817A - Substrate processing apparatus and substrate processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speedily carry on processing of drying a substrate that has been cleaned with a cleaning liquid and then cleaned with a rinse liquid with a simple apparatus configuration.SOLUTION: A displacement liquid heated to a temperature higher than the solidification point of a sublimable substance is supplied to a surface of a wafer W, and then a processing liquid including a liquid sublimable substance is heated to a temperature higher than the solidification point and supplied through a common nozzle 5. The displacement liquid is thus supplied to substitute the displacement liquid for the rinse liquid and also to heat the surface of the wafer W simultaneously, and the processing liquid having the temperature higher than the solidification point is supplied to the wafer W that has been heated so as to spread a liquid film of the processing liquid thin over the wafer W. The apparatus configuration is simple since the heated displacement liquid and processing liquid are supplied to the surface of the wafer W. In addition, since the thin liquid film of the processing liquid can be formed, the time required for solidification and sublimation of the sublimable substance is shortened and the processing of drying the substrate is speedily carried on.

Description

  The present invention relates to a substrate processing apparatus and a substrate processing method for drying a substrate after cleaning the surface of the substrate with a cleaning liquid and subsequently with a rinsing liquid.

  In a single wafer spin cleaning apparatus that cleans a substrate to be processed, such as a semiconductor wafer (hereinafter referred to as a wafer), the wafer surface is rotated by rotating the wafer while supplying, for example, an alkaline or acidic chemical solution to the surface of the wafer. The garbage etc. are removed. The chemical solution remaining on the wafer surface is removed by rinsing using, for example, pure water, and then the wafer is rotated to perform shake-off drying to shake off the remaining liquid.

  However, as semiconductor devices are highly integrated, the problem of so-called pattern collapse is increasing in the process of removing such liquids. Pattern collapse is caused by uneven drying of the liquid on the left and right sides of the projections and depressions that form the pattern on the wafer surface, resulting in an unbalanced surface tension that pulls the projections to the left and right, leaving much liquid. It is a phenomenon that the convex part falls down in the direction of being.

  As a method for removing the liquid remaining on the wafer surface while suppressing the occurrence of pattern collapse, IPA (isopropyl alcohol) having a low surface tension is supplied to the wafer surface after rinsing with pure water, and the pure water is replaced with IPA. A method is known in which IPA is changed to a gas and dried. However, since IPA has a non-zero surface tension, this approach is limited in principle.

  A drying method using a supercritical fluid (supercritical fluid) which is a kind of high-pressure fluid is also known. In this method, there is no interface between the supercritical fluid and the liquid or gas in equilibrium, so the liquid on the wafer is replaced with the supercritical fluid, and then the state of the supercritical fluid is changed to a gas. The liquid can be dried without being affected by the surface tension. However, this method requires high-voltage equipment, and the apparatus becomes large.

  Further, in Patent Document 1, in a photomask dry cleaning method, an isopropyl alcohol solution of naphthalene is dropped onto a photomask after exposure to spin coat a naphthalene protective film, and then the substrate is heated to form a protective film and A technique for removing dust is described. Furthermore, in Patent Document 2, the substrate is immersed in an IPA solution to replace pure water on the substrate with IPA, and then the substrate is immersed in a naphthalene solution. And the technique which sublimates after solidifying naphthalene by pulling up a board | substrate in the air is described. Furthermore, Patent Document 3 discloses that after replacing the liquid on the substrate with a replacement liquid that is difficult to mix with the liquid and having a lower freezing point than the liquid, only the liquid is solidified to remove the replacement liquid, A technique for removing and drying the solidified body is described. However, even if these techniques are used, it is difficult to quickly proceed with a simple apparatus configuration, in which the substrate is cleaned with a cleaning solution and subsequently dried with a rinse solution.

JP-A-63-41855 JP-A-9-190996 (paragraphs 0027 and 0034) JP 2008-66272 A (paragraphs 0017, 0034, 0038 to 0040)

  The present invention has been made in view of such circumstances, and a purpose thereof is a technique for promptly advancing a process of cleaning with a cleaning liquid and subsequently drying a substrate cleaned with a rinsing liquid with a simple apparatus configuration. Is to provide.

For this reason, the substrate processing apparatus of the present invention is an apparatus that performs processing for drying the substrate after cleaning the surface of the substrate with a cleaning liquid and subsequently cleaning with a rinse liquid.
A substrate holder for horizontally holding the substrate;
A first nozzle that supplies a replacement liquid composed of an ambipolar liquid for replacing the rinse liquid on the substrate held by the substrate holding unit to the surface of the substrate;
A second nozzle for supplying a processing liquid containing a liquid sublimable substance from a processing liquid supply source onto the surface of the substrate to which the replacement liquid is supplied from the first nozzle;
A first heating unit for preheating the replacement liquid so that the temperature of the replacement liquid discharged from the first nozzle is higher than the freezing point of the sublimable substance;
A second heating unit for heating the treatment liquid so that the temperature of the treatment liquid from the treatment liquid supply source to the discharge port of the second nozzle is higher than the freezing point of the sublimable substance; It is provided with.

Further, the substrate processing method of the present invention is a processing method performed to dry the substrate after cleaning the surface of the substrate with a cleaning liquid and subsequently cleaning with a rinse liquid.
Holding the substrate horizontally on the substrate holder;
Supplying a replacement liquid composed of an ambipolar liquid to the surface of the substrate held by the substrate holding section to replace the rinse liquid on the substrate with the replacement liquid;
Supplying a treatment liquid containing a liquid sublimable substance to the surface of the substrate supplied with the substitution liquid from a treatment liquid supply source through a nozzle;
Before supplying the replacement liquid to the surface of the substrate, preheating the replacement liquid so that the temperature of the replacement liquid is higher than the freezing point of the sublimable substance;
Heating the treatment liquid so that the temperature of the treatment liquid from the treatment liquid supply source to the nozzle outlet is higher than the freezing point of the sublimable substance.

  According to the present invention, since the substrate is supplied with the replacement liquid heated to a temperature higher than the freezing point of the sublimable substance before supplying the treatment liquid containing the liquid sublimable substance to the substrate. Further, the replacement of the rinse liquid with the replacement liquid and the heating of the surface of the substrate can be performed simultaneously. Further, since the processing liquid having a temperature higher than the freezing point is supplied to the heated substrate through the nozzle, the liquid film of the processing liquid can be spread thinly on the substrate. Since the heated replacement liquid and processing liquid are supplied to the substrate surface in this way, the apparatus configuration is simplified, and a thin liquid film of the processing liquid can be formed on the substrate. The time required for solidification and sublimation of the substrate can be shortened, and the processing for drying the substrate can be rapidly advanced.

It is a longitudinal cross-sectional view which shows the substrate processing apparatus which concerns on embodiment of this invention. It is a top view which shows the said substrate processing apparatus. It is a block diagram which shows the common nozzle provided in the said substrate processing apparatus, and the supply system of this common nozzle. It is a block diagram which shows the solidification detection part provided in the said substrate processing apparatus. 2 is a perspective view showing a surface state of a wafer W. FIG. It is a perspective view explaining the substrate processing method implemented with the said substrate processing apparatus. It is a perspective view explaining the said substrate processing method. It is a longitudinal cross-sectional view explaining the effect | action of this invention. It is a longitudinal cross-sectional view explaining the effect | action of this invention. It is a longitudinal cross-sectional view explaining the effect | action of this invention. It is a longitudinal cross-sectional view explaining the effect | action of this invention. It is a longitudinal cross-sectional view explaining the effect | action of this invention. It is a longitudinal cross-sectional view explaining the effect | action of this invention. It is a longitudinal cross-sectional view explaining the effect | action of this invention. It is a block diagram which shows the other example of the shared nozzle of this invention. It is a top view which shows the other example of the substrate processing apparatus of this invention. It is a side view explaining the effect | action of the example shown in FIG. It is a side view explaining the effect | action of the example shown in FIG. It is a side view explaining the effect | action of the example shown in FIG. It is a side view which shows the other example of a solidification detection part. It is a side view which shows the other example of a solidification detection part. It is a side view which shows the other example of a solidification detection part. It is a side view which shows the other example of a solidification detection part. It is a side view which shows the other example of a solidification detection part. It is a perspective view which shows the other example of the nozzle which supplies a process liquid.

  An embodiment of a substrate processing apparatus 1 according to the present invention will be described. As shown in FIG. 1, the substrate processing apparatus 1 includes a spin chuck 2 that holds a substrate, for example, a wafer W horizontally, inside a processing container 10. The spin chuck 2 constitutes a substrate holding unit, and is configured to be rotatable and raised and lowered around a vertical axis by a rotation driving unit 22 via a rotation shaft 21.

  A processing cup 3 is provided around the spin chuck 2. This processing cup 3 circulates the atmosphere on the side upper side of the wafer W on the spin chuck 2 and the inner cup 31 disposed so as to face the peripheral edge of the back surface of the wafer W held on the spin chuck 2. The outer cup 32 is provided so as to cover the direction. In the figure, 33 is a liquid receiving portion, and a drain path 34 is connected to the lower surface of the liquid receiving portion 33 in order to discharge the processing liquid. The liquid is guided to the drainage channel 34 via the inner cup 31. Further, an exhaust path 35 is connected to the liquid receiving portion 33 in order to exhaust the atmosphere in the processing container 10.

  A cleaning liquid nozzle 41 that discharges a cleaning liquid that is a chemical liquid to the surface of the wafer W and a rinsing liquid nozzle 42 that discharges a rinsing liquid are provided in the processing container 10. Examples of the cleaning liquid include SC1 liquid (mixed liquid of ammonia and hydrogen peroxide solution), DHF (dilute hydrofluoric acid), SC2 liquid (mixed liquid of hydrochloric acid and hydrogen peroxide solution), and SPM (sulfuric acid and hydrogen peroxide solution). Mixture) and the like, and pure water is used as the rinse liquid. As shown in FIGS. 1 and 2, the nozzles 41 and 42 are configured to be movable between a supply position for supplying a cleaning liquid or the like to the central portion of the wafer W and a standby position outside the processing cup 3, for example. ing. In this example, the cleaning liquid nozzle 41 is supported by an arm 43, and can be moved up and down by an elevating mechanism 43A and can be advanced and retracted by an advance / retreat mechanism 43B. The rinsing liquid nozzle 42 is supported by an arm 44 and is configured to be movable up and down by an elevator mechanism (not shown) and to be advanced and retracted by an advance / retreat mechanism 44B.

  The cleaning liquid nozzle 41 is connected to a supply source 45A of SC1 liquid as a cleaning liquid via a supply path 45 provided with a flow rate adjusting valve V1. The rinsing liquid nozzle 42 is connected to a supply source 46A of pure water, which is a rinsing liquid, via a supply path 46 having a flow rate adjusting valve V2.

  Furthermore, a shared nozzle 5 is provided in the processing container 10. The shared nozzle 5 supplies a replacement liquid made of an bipolar liquid and a processing liquid containing a liquid sublimable substance to the surface of the wafer W held on the spin chuck 2. The ambipolar liquid is a liquid that has the property of dissolving in water and dissolving organic substances, and is made of, for example, alcohols such as IPA, methanol, and ethanol. The sublimable substance is a substance that sublimates from a solid to a gas in the atmosphere, and is made of, for example, paradichlorobenzene (PDCB) or naphthalene. As the liquid sublimable substance, a substance obtained by melting a sublimable substance may be used, or a substance obtained by dissolving a sublimable substance in a substitution liquid may be used. Here, the description will be continued with an example in which IPA is used as the replacement liquid which is an ambipolar liquid and liquid PDCB is used as the processing liquid.

  As shown in FIGS. 1 and 2, the common nozzle 5 is movable between a supply position for supplying a replacement liquid or a processing liquid to the center of the wafer W and a standby position outside the processing cup 3, for example. It is configured. In this example, the nozzle 5 is supported by an arm 51, and can be moved up and down by an elevating mechanism 52A and can be advanced and retracted by an advancing and retracting mechanism 52B.

  As shown in FIG. 3, the common nozzle 5 is provided with a flow path 50 for a replacement liquid and a processing liquid, and a discharge port 5a is formed at the lower end of the nozzle. Further, the replacement liquid and the processing liquid are supplied to the flow path 50 of the common nozzle 5 through the common flow path 53. The upstream side of the common flow channel 53 branches into a first flow channel 54 and a second flow channel 55, and the first flow channel 54 is connected to the IPA supply source 54A via the flow rate adjusting valve V3. The second flow path 55 is connected to a PDCB supply source 55A, which is a processing liquid supply source, through a flow rate adjustment valve V4. The first flow path 54 is a flow path for flowing the replacement liquid exclusively, the second flow path 55 is a flow path for flowing the treatment liquid exclusively, and the flow rate adjusting valves V3 and V4 are flow path switching mechanisms. It corresponds to. The IPA supply source 54A and the PDCB supply source 55A are connected to a gas supply source 513 of a pressure-feeding gas such as nitrogen gas via supply paths 511 and 512 each having valves Va and Vb, respectively. Then, the control unit 8 outputs control signals to the valves V3, V4, Va, and Vb, and supplies the IPA supply source 54A and the PDCB supply source 55A, respectively by supplying the pressure-feeding gas to the IPA supply source 54A and the PDCB supply source 55A. IPA and liquid PDCB are supplied from the source 55A to the common nozzle 5 through the common flow path 53, and IPA and liquid PDCB can be supplied separately or simultaneously.

  Further, in this example, the upstream portion of the common flow channel 53, that is, the first flow channel 54, the second flow channel 55, the flow rate adjusting valves V3 and V4, the IPA supply source 54A and the PDCB supply source 55B are a thermostatic chamber. 56 is provided. This constant temperature bath 56 corresponds to a first heating unit for preheating the replacement liquid so that the temperature of the replacement liquid discharged from the common nozzle 5 is higher than the freezing point of PDCB which is a sublimable substance. At the same time, the second treatment liquid is heated so that the temperature of the treatment liquid from the PDCB supply source 55A to the discharge port 5a of the common nozzle 5 is higher than the freezing point of PDCB which is a sublimable substance. Corresponds to the heating section.

  The thermostatic chamber 56 is filled with a fluid 57 such as water, and includes a heating mechanism 58. Thus, the fluid 57 is heated by the heating mechanism 58, whereby the IPA in the IPA supply source 54A and the PDCB in the PDCB supply source 55A are maintained at a predetermined temperature. In this example, the fluid 57 is covered to the vicinity of the upstream end of the common flow channel 53.

  At this time, when PDCB is discharged from the discharge port 5 a of the common nozzle 5, it is assumed that the temperature slightly decreases due to the flow of the common flow channel 53, and even if this temperature decrease occurs, the discharge port 5 a The temperature in the thermostatic chamber 56 is set so that the temperature of the PDCB when discharged is higher than the freezing point. For this reason, since the melting point of PDCB is 55 ° C., the temperature of the IPA in the IPA supply source 54A and the temperature of the PDCB in the PDCB supply source 55A are, for example, 60 ° C. to 120 ° C., preferably 70 ° C. The temperature is set to be maintained.

  The cleaning liquid nozzle 41, the rinsing liquid nozzle 42 and the common nozzle 5 are normally provided at a standby position, and when supplying various chemicals to the wafer W, they move to the supply position. At this time, the cleaning liquid nozzle 41, the rinsing liquid nozzle 42 and the common nozzle 5 are provided so as to be movable between the standby position and the supply position without interfering with each other. In addition, a drainage unit 59 is provided below the shared nozzle 5 at the standby position. When the shared nozzle 5 is at the standby position, the replacement liquid is supplied from the discharge port 5a of the nozzle 5 to the drainage unit 59. And the processing liquid can be discharged.

  Further, the processing container 10 is provided with a solidification detection unit 6. The solidification detection unit 6 irradiates the surface of the wafer W with light, and detects that the sublimable substance existing on the surface of the wafer W is solidified based on the reflected light. For example, as shown in FIG. 4, the solidification detection unit 6 of this example includes a light emitting unit 61 that emits light toward the wafer W on the spin chuck 2 and a light receiving unit 62 that receives light reflected by the surface of the wafer W. And. The light receiving unit 62 is configured to detect, for example, the amount of reflected light and output a binarized signal (0, 1) to the control unit 8 described later based on a threshold value.

  That is, as described later, in a state where a liquid film of a sublimable substance is formed on the wafer W, the liquid film is colorless and transparent, and thus the ground color of the wafer W is visible. Next, when the sublimable substance is solidified, it becomes cloudy, and when the sublimable substance is sublimated, the ground color of the wafer W becomes visible again. In FIG. 5, assuming that the hatching of the dots is the ground color of the wafer W, and the hatching of the diagonal lines is the cloudy color of the solidified substance of the sublimable substance, FIG. 5 (b) shows a state where the sublimable substance is solidified, and FIG. 5 (c) shows a state where the sublimable substance is sublimated. Thus, when the sublimable substance is solidified, the color changes to a cloudy color, so that the amount of reflected light is reduced. For this reason, for example, a threshold value of the light amount is obtained in advance, and the detection signal “1” is output to the control unit 8 when the threshold value becomes smaller than this threshold value.

  The solidification detection unit 6 is provided, for example, by a support member 63 at a position where light can be emitted from the light emitting unit 61, for example, in the vicinity of the periphery of the wafer. The solidification detection unit 6 is a position that does not hinder the transfer of the wafer W between the spin chuck 2 and an external transfer mechanism (not shown) and the movement of the cleaning liquid nozzle 41, the rinsing liquid nozzle 42, and the common nozzle 5. These nozzles 41, 42, 5 are provided at positions where light rays are not blocked.

  Further, a fan filter unit (FFU) 11 for supplying clean gas to the inside of the processing container 10 is connected to the ceiling surface of the processing container 10, and an exhaust pipe 12 is connected to the bottom surface. Thus, a downdraft is formed in the processing container 10. In FIG. 2, reference numeral 13 denotes a transfer port for carrying the wafer W in and out of the processing container 10, and reference numeral 14 denotes a shutter for opening and closing the transfer port 13.

  In such a liquid processing apparatus 1, the operation of each device in the liquid processing apparatus 1 is comprehensively controlled by the control unit 8. The control unit 8 is composed of a computer, for example, and has a program storage unit (not shown). The program storage unit stores a program in which instructions are set so that processing for drying a substrate, which will be described later, is performed. And this program is read by the control part 8, The control part 8 is the rotation drive part 22 of the spin chuck 2, each flow volume adjustment valve V1-V4, the on-off valve Va, the liquid feeding pump P, each nozzle 41, Control signals are output to the elevating mechanisms 43A and 52A, the advance / retreat mechanisms 43B, 44B, and 52B. The program is stored in the program storage unit while being stored in a storage medium such as a hard disk, a compact disk, a magnetic optical disk, or a memory card.

  Further, the control unit 8 determines the timing of solidification of the sublimable substance on the wafer W based on the detection signal from the solidification detection unit 6, and uses the signal as a trigger signal for unloading the wafer W from the spin chuck 2. Configured to be used as That is, after the sublimable substance supplied on the wafer is solidified, the sublimable substance is sublimated by being left naturally as described later. For this reason, when the sublimable substance is solidified, the wafer W is unloaded from the spin chuck 2 and a subsequent process is performed, so that the drying of the wafer W proceeds promptly. The latter stage processing is natural standing or reduced pressure drying processing. Therefore, by detecting that the sublimable substance is solidified and using this detection signal as a trigger signal for unloading the wafer W from the spin chuck 2, the solidified wafer W is transferred to a subsequent process, The next wafer W can be transferred to the spin chuck 2, and the throughput of processing can be improved.

  Therefore, for example, the control unit 8 monitors the output signal of the solidification detection unit 6 from the time when the cleaning liquid is supplied to the wafer W, and at the timing when the detection signal from the solidification detection unit 6 becomes “1”. Therefore, in order to unload the wafer W from the spin chuck 2, a control signal is output to the spin chuck 2 and an external transfer mechanism. In addition, at the timing when the detection signal from the solidification detection unit 6 becomes “1”, an indication that solidification is completed is displayed on a display unit (not shown), and the operator carries out the wafer W from the spin chuck 2 based on this display. A command may be output to the spin chuck 2 and an external transport mechanism.

  Next, the operation of the above-described embodiment will be described with reference to FIGS. First, the wafer W is loaded into the processing container 10 from the transfer port 13 by an external transfer mechanism (not shown) and transferred to the spin chuck 2 raised to the upper side of the processing cup 3. Then, the wafer W is held by the spin chuck 2 and lowered to a predetermined position in the processing cup 3. On the other hand, the transport mechanism is retracted and the shutter 14 is closed.

  Then, the cleaning liquid nozzle 41 is moved to the supply position, and the SC1 liquid as the cleaning liquid is discharged onto the surface of the wafer W while rotating the wafer W (FIG. 6A). As a result, particles and organic contaminants adhering to the surface of the wafer W are removed. Next, the rinsing liquid nozzle 42 is moved to the supply position, and pure water as a rinsing liquid is discharged onto the surface of the wafer W while rotating the wafer W (FIG. 6B). Thus, the cleaning liquid on the surface of the wafer W is washed away by the rinse liquid.

  Subsequently, the shared nozzle 5 is moved to the supply position (FIG. 6C). Then, while rotating the wafer W, the flow rate adjustment valve V3 is opened, and IPA is supplied from the IPA supply source 54A to the common nozzle 5 through the first flow path 54 and the common flow path 53. Thus, 70 ° C. IPA, which is a high-temperature bipolar liquid, is discharged from the common nozzle 5 to replace the rinse liquid on the wafer W with IPA (FIG. 8).

  Here, FIGS. 8 to 14 schematically show how the pattern 71 is formed on the surface of the wafer W. FIG. When IPA is supplied to the surface of the wafer W, it is diffused outward by centrifugal force and spreads over the entire surface of the wafer W, thus rinsing liquid on the surface of the wafer W is replaced with IPA. At this time, IPA enters the pattern 71, and a liquid film 72 of IPA is formed on the surface of the pattern 71. Further, since IPA of about 70 ° C. is supplied and diffused on the surface of the wafer W, the surface of the wafer W is heated to a temperature higher than the freezing point of PDCB which is a sublimable substance.

  Subsequently, the chemical liquid supplied from the common nozzle 5 to the wafer W is switched from the replacement liquid to the liquid PDCB which is the processing liquid, and detection from the solidification detection unit 6 is started. For example, when the chemical solution is switched, the flow rate adjustment valve V4 is opened together with the flow rate adjustment valve V3, and IPA and liquid PDCB at a predetermined flow rate are respectively supplied from the IPA supply source 54A and the PDCB supply source 55A into the common nozzle 5 through the common flow path 53. Supply (see FIG. 9). At this stage, a liquid film 73 in which PDCB is dissolved in IPA is formed on the surface of the wafer W.

  Then, the flow rate adjusting valve 3 is gradually throttled, and finally only liquid PDCB is supplied (FIGS. 7A and 10). At this time, when the PDCB is supplied, the wafer W is rotated at a high rotational speed, such as 1000 rpm to 3000 rpm, at which a thin liquid film of PDCB can be formed. As described above, the wafer W may be rotated at such a rotational speed that a thin PDCB liquid film can be formed, when PDCB and IPA are supplied simultaneously, or when only PDCB is supplied.

  As a result, the PDCB on the surface of the wafer W is diffused outward by centrifugal force and spreads over the entire surface of the wafer W. By supplying liquid PDCB in this way, IPA on the surface of the wafer W is replaced with PDCB. However, since IPA has a property of dissolving PDCB, a part of IPA remains in PDCB. Thus, a liquid film 74 having a PDCB concentration higher than that of the liquid film 73 is formed on the surface of the wafer W.

  At this time, IPA of about 70 ° C. is supplied in the previous step, and the surface of the wafer W is heated to a temperature higher than the freezing point of the sublimable substance, so that the liquid PDCB is immediately solidified on the wafer W. It can be suppressed. Further, since the wafer W is rotated at the above-described rotation speed, the liquid PDCB spreads uniformly and thinly on the surface of the wafer W, and a thin PDCB liquid film can be formed. Further, since the high temperature replacement liquid is supplied to the common flow path 53 and the flow path 50 of the common nozzle 5 before the supply of the sublimable substance, the inner walls of the common flow path 53 and the flow path 50 are replaced by the high temperature replacement liquid. It is warmed. For this reason, when the processing liquid is supplied to the common flow path 53 and the flow path 50 next to the replacement liquid, it is possible to prevent the sublimable substance from solidifying during the flow through the common flow path 53 and the like.

  After the liquid film 74 of PDCB is formed in this way, the flow rate adjusting valve V4 is closed to stop the discharge of PDCB from the common nozzle 5, and the rotation speed of the wafer W is reduced to about 50 rpm to 1000 rpm, and the common nozzle 5 is moved to the standby position. When the wafer W continues to rotate at a rotational speed of about 50 rpm to 1000 rpm, the melting point of the PDCB is 55 ° C. and the thickness is thin, so that it is naturally cooled and solidified by a vortex generated by the rotating air current. The

  On the other hand, for the common nozzle 5 at the standby position, as shown in FIG. 7B, the flow rate adjustment valve V3 is opened, and the IPA supply source 54A passes through the first flow path 54 and the common flow path 53. A predetermined amount of IPA is supplied to the flow path 50 in the nozzle 5 and discharged to the drainage part 59. Thus, even if PDCB is solidified and adhered to the common flow channel 53 and the flow channel 50 of the common nozzle 5 by passing the high temperature IPA through the common flow channel 53 and the flow channel 50 of the common nozzle 5, The solidified material is dissolved in IPA and removed.

  As described above, by supplying the liquid PDCB, the IPA on the surface of the wafer W is replaced with the PDCB, but a part of the IPA remains in the PDCB. As shown in FIG. 11, when the PDCB is solidified, the IPA in the PDCB is volatilized. Therefore, as shown in FIG. 12, the portion where the IPA is removed is formed as a fine hole 75 in the solidified PDCB. The solidified product 76 of PDCB is in a porous state.

  By the way, as described above, when the PDCB is solidified, a detection signal “1” is output from the solidification detection unit 6 to the control unit 8. Accordingly, the control unit 8 always obtains a detection signal from the solidification detection unit 6 from the start of supply of the processing liquid, and when the detection signal “1” is input, the wafer W is unloaded from the spin chuck 2. It is determined that a trigger signal has been acquired. Then, for example, the rotation of the spin chuck 2 is stopped, the spin chuck 2 is moved up to the delivery position, and an unload command for the wafer W on the spin chuck 2 is output to a transfer mechanism (not shown), for example.

  The transfer mechanism receives the wafer W solidified by the PDCB, and transfers the wafer W to an area where subsequent processing is performed. The region where the subsequent processing is performed may be, for example, a region where the sublimable substance is naturally sublimated while the wafer W is placed on a mounting table placed in an air atmosphere, or the wafer W is decompressed. It may be a reduced-pressure drying apparatus that sublimates the sublimable substance by drying.

  Thus, as shown in FIG. 13, by sublimating the solid state PDCB, the PDCB is gradually removed from the pattern 73 on the wafer surface, and as shown in FIG. 14, all the PDCB is removed and the wafer is removed. The drying process ends. At this time, as described above, since a thin PDCB liquid film is formed, the solidified product 76 of PDCB is also thin, and the solidified product 76 is formed in a porous shape, so that the sublimation speed is large and the sublimation is not performed. Finish in a short time.

  According to the above-described embodiment, after the rinsing liquid on the wafer W is replaced with the replacement liquid, and then the replacement liquid is replaced with the processing liquid, the sublimable substance is solidified and sublimated. Therefore, after the surface of the wafer W is cleaned with a cleaning liquid and subsequently with a rinsing liquid, the process for drying the wafer W is performed using solid sublimation, and thus surface tension may be generated. The wafer W can be dried while suppressing the occurrence of pattern collapse.

  At this time, before the treatment liquid containing the liquid sublimable substance is supplied to the wafer W cleaned with the rinse liquid, the replacement liquid made of the bipolar liquid is supplied. In general, sublimable substances are difficult to mix with pure water, which is a rinsing liquid, but the ambipolar liquid dissolves in water and has a property of dissolving organic substances, so it is easy to mix with both rinsing liquid and sublimable substances. . For this reason, the rinsing liquid is replaced with a bipolar liquid, and then the bipolar liquid is replaced with a sublimable substance. As a result, the rinsing liquid can be quickly replaced with a sublimable substance.

  The replacement liquid made of the bipolar liquid is heated in advance by the first heating unit so that the temperature of the replacement liquid discharged from the common nozzle 5 is higher than the freezing point of the sublimable substance. For this reason, the supply of the replacement liquid heats the wafer W to a temperature equal to or higher than the freezing point of the sublimable substance, and the wafer W can be heated by a simple method of supplying the replacement liquid. At this time, the replacement liquid is heated to the temperature by placing the IPA supply source 54A in the thermostatic chamber 56 which is the first heating unit, so that the heating of the replacement liquid itself can be performed with a simple apparatus configuration. . On the other hand, considering the provision of a heating mechanism in the spin chuck 2 to heat the wafer W itself, the structure of the spin chuck 2 becomes complicated because the spin chuck 2 is configured to be rotatable. Further, in order to uniformly heat the wafer surface, it is necessary to enlarge the spin chuck 2 itself, resulting in a large apparatus configuration when viewed as a whole processing apparatus.

  Furthermore, in this embodiment, the treatment liquid is in a second state so that the temperature of the treatment liquid from the PDCB supply source 55A to the discharge port 5a of the common nozzle 5 is higher than the freezing point of the sublimable substance. Since it is heated by the heating unit, the liquid sublimable substance can be supplied to the surface of the wafer W from the common nozzle 5 while suppressing the solidification of the sublimable substance. At this time, since the processing liquid is heated by disposing the PDCB supply source 55A in the thermostatic chamber 56 that is also the second heating unit, the processing liquid can be heated with a simple apparatus configuration. Further, if the IPA supply source 54A and the PDCB supply source 55A are arranged in the common thermostat 56 as in the above-described embodiment, both the replacement liquid and the processing liquid are heated by one heating unit. Therefore, the device configuration can be simplified.

  When the processing liquid is supplied from the common nozzle 5, the surface of the wafer W is heated by the supply of the replacement liquid, so that the sublimable substance is prevented from solidifying immediately. For this reason, since a process liquid can be spread thinly, the liquid film of a thin process liquid can be formed. At this time, the processing liquid is supplied from the common nozzle 5 to the center of the wafer W, and the wafer W is rotated at a rotational speed of, for example, 1000 rpm to 3000 rpm. A liquid film of liquid can be formed. In this way, when the liquid film of the processing liquid can be formed thin, the amount of sublimable substance is small, so the time required for solidification of the sublimable substance and sublimation of the solidified sublimable substance is shortened. The process for drying the water quickly proceeds, and the time required for the drying process is shortened.

  Moreover, since the liquid supplied to the common flow path 53 by the flow path switching mechanism is switched between the replacement liquid and the processing liquid and supplied using the common nozzle 5, the processing liquid is supplied to the common nozzle 5. Thereafter, the replacement liquid can be supplied to the common nozzle 5 by switching the flow path. As a result, even if the solidified substance of the sublimable substance adheres to the common flow path 53 or the flow path 50 of the common nozzle 5, the replacement liquid heated to a temperature equal to or higher than the freezing point of the sublimable substance is allowed to flow thereafter. Thus, the solidified substance of the attached sublimable substance can be dissolved and removed in the replacement liquid.

  In addition, when the replacement liquid and the processing liquid are supplied from the common nozzle 5 to the wafer W, the replacement liquid and the processing liquid can be simultaneously supplied to the surface of the wafer W at the time of switching. For this reason, it is possible to prevent the sublimable substance from immediately solidifying on the surface of the wafer W, and to easily spread the processing liquid on the surface of the wafer W.

  Further, in the above-described embodiment, the replacement liquid and the processing liquid are switched and supplied, and finally only the processing liquid is supplied. Therefore, the rinsing liquid and the replacement liquid are replaced, and the replacement liquid and the processing liquid are replaced. Replacement can be performed reliably. For this reason, after the supply of the processing liquid is completed, the sublimable substance and the bipolar liquid are mixed on the surface of the wafer W as described above, but the concentration of the sublimable substance is high. For this reason, solidification and sublimation of the sublimable substance are performed quickly, and the process for drying the wafer W proceeds rapidly.

  Furthermore, in the present invention, the solidification detection unit 6 is used to detect that the sublimable substance existing on the surface of the wafer W is solidified based on the reflected light. Accordingly, it is possible to easily and accurately determine the end point of the solidification of the sublimable substance. Since this detection signal is used as a trigger signal for unloading the wafer W from the spin chuck, the solidified wafer W is quickly unloaded from the processing container 10. Therefore, since the solidified wafer W can be carried out from the spin chuck 2 and the next wafer W can be transferred to the spin chuck 2, the throughput can be improved.

  As described above, in the present invention, as shown in FIG. 15, the common channel 81 for supplying the replacement liquid and the processing liquid to the common nozzle 5 may have a double pipe structure. The common flow path 81 includes an inner pipe 82 and an outer pipe 83 around the inner pipe 82. A processing liquid is supplied to the inner pipe 82. Replacement fluid is supplied. The outer pipe 83 corresponds to a first flow path for flowing a replacement liquid exclusively, and the inner pipe 82 corresponds to a second flow path for flowing a processing liquid exclusively. For example, the distal end side (shared nozzle 5 side) of the inner tube 82 is shorter than the outer tube 83, and the region 84 closer to the shared nozzle 5 side than the distal end of the inner tube 82 is a common flow path for the replacement liquid and the processing liquid. It has become.

  The proximal end side of the inner pipe 82 is connected to a PDCB supply source 85A, which is a processing liquid supply source, by a flow path 85 having a flow rate adjusting valve V5. The proximal end side of the outer pipe 83 is connected to an IPA supply source 86A that is a supply source of the replacement liquid by a flow path 86 provided with a flow rate adjusting valve V6. The flow path 85 and the flow path 86 are connected by a flow path 87 provided with a flow rate adjusting valve V7. Furthermore, the flow paths 85 to 87, the flow rate adjusting valves V5 to V7, the PDCB supply source 85A, and the IPA supply source 86A are arranged in a common constant temperature bath 87, and the IPA in the IPA supply source 86A and the PDCB supply source 85A The temperature of the PDCB is controlled so as to be, for example, 60 ° C. to 120 ° C., preferably 70 ° C. In the figure, 88 is a heating mechanism. In FIG. 15, the open / close valve Va and the liquid feed pump P are not shown, but they are provided in the common flow path 81 as in FIG.

  In such a configuration, when supplying the replacement liquid to the wafer W, the common nozzle 5 is moved to the supply position, the flow rate adjusting valve V6 is opened, and the replacement liquid is supplied to the outer tube 83 through the flow path 86. When supplying the processing liquid to the wafer W, for example, first, the flow rate adjustment valve V5 is opened together with the flow rate adjustment valve V6. Thus, the replacement liquid is supplied to the outer tube 83 via the flow path 86, while the processing liquid is supplied to the inner pipe 82 via the flow path 85. As a result, the replacement liquid and the processing liquid are mixed in the region 84 and supplied to the wafer W from the discharge port 5 a through the flow path 50 of the common nozzle 5. Next, the flow rate adjustment valve V6 is gradually throttled to switch to supplying only the processing liquid. On the other hand, after the formation of the liquid film of the processing liquid is completed, the common nozzle 5 is moved to the standby position. Then, the flow rate adjusting valves V5 and V7 are opened, the replacement liquid is supplied from the IPA supply source 86A to the flow path 50 of the common nozzle 5 through the flow path 87 and the flow path 85, and discharged to a drainage section (not shown). Thereby, even if the solidified substance of the sublimable substance adheres to the inner pipe 82 or the inside 50 of the common nozzle 5, the solidified part is dissolved and removed by the replacement liquid.

  In the shared nozzle 5 having such a configuration, since the high-temperature replacement liquid is supplied to the outer tube 83, the periphery of the inner tube 82 is heated. For this reason, when the treatment liquid is supplied to the inner pipe 82 after the replacement liquid, it is possible to prevent the sublimable substance from solidifying during the flow of the inner pipe 82.

  Further, in the present invention, as shown in FIGS. 16 and 17, the first nozzle 91 for supplying a replacement liquid to the surface of the wafer W held on the spin chuck 2 and the wafer W held on the spin chuck 2. A second nozzle 92 for supplying a processing liquid may be separately provided on the surface of the first nozzle. The first nozzle 91 and the second nozzle 92 are supplied to a central position on the surface of the wafer W by a moving mechanism 91A and a moving mechanism 92A, and a standby position outside the processing cup 3, respectively. It is configured to be movable between positions.

  As shown in FIG. 17, the first nozzle 91 is connected to a replacement liquid supply source (IPA supply source) 93A through a supply path 93 provided with a flow rate adjusting valve V8. As shown in FIGS. 18 and 19, the second nozzle 92 is connected to a processing liquid supply source (PDCB supply source) 94A via a supply path 94 provided with a flow rate adjusting valve V9. Here, the upstream side of the flow rate adjusting valve V9 in the supply path 94 is connected to a solvent supply source 95A of a sublimable substance via a flow path 95 provided with a flow rate adjusting valve V10. Note that the IPA supply source 93A, the PDCB supply source 94A, and the solvent supply source 95A are heated by a heating unit (not shown) so that each liquid becomes, for example, 70 ° C. In FIG. 19, 96 is a drainage part. Further, the solvent for the sublimable substance may be a substitution liquid or another organic solvent.

  In such a configuration, when supplying the replacement liquid to the wafer W, the first nozzle 91 is moved to the supply position, the flow rate adjustment valve V8 is opened, and the replacement liquid is supplied through the flow path 93. When supplying the processing liquid to the wafer W, the supply of the replacement liquid from the first nozzle 91 is stopped, the first nozzle 91 is moved to the standby position, and then the second nozzle 92 is moved to the supply position. At the same time, the flow rate adjusting valve V9 is opened and the processing liquid is supplied through the flow path 94. After the formation of the liquid film of the processing liquid is completed, the second nozzle 92 is moved to the standby position. Next, the flow rate adjusting valves V9 and V10 are opened, and the solvent is supplied from the solvent supply source 95A to the second nozzle 92 via the flow path 95 and the flow path 94 and discharged to the liquid discarding section 96. As a result, even if a solidified substance of a sublimable substance adheres in the second nozzle 92 or the supply path 94, the solidified substance is dissolved and removed by the solvent.

  Furthermore, the solidification detection unit of the present invention may be configured as shown in FIGS. The solidification detection unit 6A in this example includes a slit member 6 in order to selectively receive light reflected by the surface of the wafer W. As shown in FIG. 20, when the liquid film 67 is formed on the surface of the wafer W, the slit member 65 transmits the light emitted from the light emitting unit 61 through the liquid film 67 and is reflected by the surface of the wafer W. It is configured to enter the light receiving unit 62 through the opening 66 of the slit member 65.

  Further, when the solidified sublimable substance 68 is formed on the surface of the wafer W, the light emitted from the light emitting unit 61 is reflected by the sublimable substance 68 on the surface of the wafer W as shown in FIG. Therefore, since the height position when reflecting the sublimable substance 68 by the thickness is different, the optical path of the reflected light is different. At this time, since the opening 66 of the slit member 65 is formed to transmit the reflected light in the state of FIG. 20, a layer of the solid sublimable substance 68 is formed as in the state of FIG. In this case, the reflected light is not transmitted through the opening 66 but is blocked by the slit member 65 and is not incident on the light receiving unit 62.

  Accordingly, when the sublimable substance existing on the surface of the wafer W changes from a liquid state to a solid state, the amount of light becomes lower than a predetermined threshold value. At this time, the detection signal “1” is output to the control unit 8. With this configuration, it is possible to detect that the sublimable substance existing on the surface of the wafer W is solidified.

  Further, the solidification detection unit 6B irradiates the surface of the wafer W with laser light, grasps the distance from the wafer W based on the reflected light, and thereby the sublimation substance existing on the surface of the wafer W is solidified. The structure which detects this may be sufficient. 22 shows a state in which a liquid film 67 of a sublimable substance is formed on the wafer W, FIG. 23 shows a state in which a layer of solidified sublimable substance 68 is formed, and FIG. 24 shows a state in which the solidified sublimable substance has sublimated. Each shows. As shown in FIG. 22, in a state where the liquid film 67 of the sublimable material is formed on the wafer W, when the distance to the wafer W is measured, the distance L1 to the surface of the wafer W through the liquid film 67 on the surface of the wafer W is measured. Is detected. Further, when the solidified sublimable substance 68 layer is formed as shown in FIG. 23, the distance L2 to the surface of the sublimable substance 68 layer is detected, and when the sublimable substance is sublimated as shown in FIG. The distance L1 to the wafer W is detected again. Accordingly, the solidification detection unit 6B may be configured to obtain a threshold value for the distance and detect that the sublimable substance is solidified when the distance becomes shorter than the threshold value.

  In the present invention, in the state where the wafer W is held by the spin chuck 2, the solidified sublimation substance may be sublimated and the drying process of the wafer W may be terminated. At this time, the solidification detection unit may detect that the sublimable substance has sublimated. When the sublimation substance is sublimated on the spin chuck 2 and the sublimation substance is detected to be sublimated as described above, the sublimation detection signal is used to unload the wafer W from the spin chuck 2. It may be used as a trigger signal.

  For example, in the solidification detection unit 6 shown in FIGS. 4 and 5, when the sublimable substance sublimates, the ground color of the wafer W is visible, so that the amount of reflected light increases. For this reason, for example, when the supply of the treatment liquid is started, detection by the solidification detection unit 6 is started, and when the light quantity becomes larger than the threshold value due to solidification and the light quantity becomes smaller than the threshold value again, the sublimable substance sublimates. The solidification detection unit 6 may be configured to detect this.

  20 and 21, when the sublimable substance sublimates, the reflected light passes through the opening 66 of the slit member 65 and enters the light receiving unit 62, so that the amount of light increases. For this reason, for example, when the supply of the treatment liquid is started, detection by the solidification detection unit 6A is started, and when the amount of light that has become smaller than the threshold due to solidification becomes larger than the threshold again, the sublimable substance is sublimated. You may make it comprise the solidification detection part 6A so that it may detect.

  Furthermore, in the solidification detection unit 6B described with reference to FIGS. 22 to 24, when the sublimable substance sublimates, the distance L1 to the wafer W is detected. Therefore, for example, after the supply of the treatment liquid is started, detection by the solidification detection unit 6B is started, and when the distance that is smaller than the threshold value due to solidification becomes larger than the threshold value again, the sublimable substance is sublimated. The solidification detection unit 6B may be configured to detect this.

  In the above description, in the present invention, a common thermostat is used as the first heating unit and the second heating unit. However, the replacement liquid and the processing liquid may be heated by separate thermostats. Moreover, the 1st heating part and the 2nd heating part may be the structure which heats the supply source of a substitution liquid or a process liquid supply source with a heating mechanism other than a thermostat, a supply path, a substitution liquid, and The structure which heats a process liquid may be sufficient.

  Furthermore, when the supply of the replacement liquid to the surface of the wafer W and the supply of the processing liquid are switched, the supply of the processing liquid may be started after the supply of the replacement liquid is stopped. Further, in the present invention, as shown in FIG. 25, as the first nozzle, the second nozzle, or the common nozzle, a long nozzle 97 having a discharge port for discharging a chemical solution in the radial direction of the wafer W is used. The replacement liquid and the processing liquid may be supplied to the wafer W by moving the nozzle 97 relative to the wafer W. Even with such a nozzle 97, a treatment liquid containing a liquid sublimable substance can be applied thinly and uniformly.

  In the present invention, the process of cleaning the surface of the wafer W with the cleaning liquid and then cleaning with the rinse liquid is performed by another liquid processing apparatus, and the wafer W on which the rinse liquid remains is added to the substrate processing apparatus of the present invention. A process of transporting and drying the wafer W may be performed. Furthermore, the present invention does not necessarily need to provide a solidification detection unit.

W wafer 2 Spin chuck 22 Rotation drive unit 5 Common nozzle 56 Constant temperature bath 53 Common channel 54 First channel 55 Second channel 55A PDCB supply source 6 Solidification detection unit 61 Light emitting unit 62 Light receiving unit 7 Control unit V1 V10 Flow adjustment valve

Claims (9)

In an apparatus for cleaning the surface of a substrate with a cleaning liquid and subsequently performing a process for drying the substrate after cleaning with a rinse liquid,
A substrate holder for horizontally holding the substrate;
A first nozzle for supplying a replacement liquid composed of an ambipolar liquid for replacing the rinsing liquid on the substrate held by the substrate holding unit to the surface of the substrate;
A second nozzle for supplying a processing liquid containing a liquid sublimable substance from a processing liquid supply source to the surface of the substrate to which the replacement liquid is supplied from the first nozzle;
A first heating unit for preheating the replacement liquid so that the temperature of the replacement liquid discharged from the first nozzle is higher than the freezing point of the sublimable substance;
A second heating unit for heating the treatment liquid so that the temperature of the treatment liquid from the treatment liquid supply source to the discharge port of the second nozzle is higher than the freezing point of the sublimable substance; A substrate processing apparatus comprising: A first flow path and a second flow path for flowing the replacement liquid and the treatment liquid exclusively; and a common flow path connected to the downstream side of these flow paths via a flow path switching mechanism. Prepared,
The substrate processing apparatus according to claim 1, wherein the first nozzle and the second nozzle are shared and configured as a shared nozzle connected to a downstream end of the common flow path. The substrate holding unit is configured so that the substrate can be rotated about a vertical axis by a rotation driving unit,
3. The substrate processing apparatus according to claim 1, wherein the substrate can be rotated when the replacement liquid is supplied to the substrate and when the processing liquid is supplied to the substrate. A solidification detecting unit that irradiates light on the surface of the substrate and detects that the sublimable substance existing on the surface of the substrate is solidified based on the reflected light,
The substrate processing apparatus according to claim 1, wherein the solidification detection signal is used as a trigger signal for unloading the substrate from the substrate holding unit. In a method of performing a treatment to dry the substrate after washing the surface of the substrate with a washing liquid and subsequently washing with a rinse liquid,
Holding the substrate horizontally on the substrate holder;
Supplying a replacement liquid composed of an ambipolar liquid to the surface of the substrate held by the substrate holding section to replace the rinse liquid on the substrate with the replacement liquid;
Supplying a treatment liquid containing a liquid sublimable substance to the surface of the substrate supplied with the substitution liquid from a treatment liquid supply source through a nozzle;
Before supplying the replacement liquid to the surface of the substrate, preheating the replacement liquid so that the temperature of the replacement liquid is higher than the freezing point of the sublimable substance;
Heating the treatment liquid so that the temperature of the treatment liquid from the treatment liquid supply source to the discharge port of the nozzle is higher than the freezing point of the sublimable substance. Processing method. The step of supplying the replacement liquid to the surface of the substrate is a step of supplying the replacement liquid to the surface of the substrate through the first flow path and the nozzle,
The step of supplying the processing liquid to the surface of the substrate is performed by switching the first flow path from the first flow path to the second flow path by the flow path switching mechanism, 6. The substrate processing method according to claim 5, wherein the substrate processing method is a step of supplying the surface.   7. The substrate processing method according to claim 5, wherein the substrate is rotated when the replacement liquid is supplied to the substrate and when the processing liquid is supplied to the substrate. Irradiating the surface of the substrate with light, and detecting that the sublimable substance existing on the surface of the substrate is solidified based on the reflected light; and
The substrate processing method according to claim 5, further comprising a step of unloading the substrate from the substrate holding portion after detecting that the sublimable substance is solidified.   9. The substrate processing method according to claim 5, wherein the sublimable substance present on the surface of the substrate is solidified in a porous shape.

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