JP5917459B2 - Ultraviolet irradiation apparatus and substrate processing method - Google Patents

Description

  The present invention relates to an ultraviolet irradiation device that irradiates a substrate with ultraviolet rays and a substrate processing method using the ultraviolet processing device.

  For example, in a manufacturing process of a semiconductor device having a multilayer wiring structure, for example, a resist coating process for applying a resist solution on a semiconductor wafer (hereinafter referred to as “wafer”) to form a resist film, and exposing a predetermined pattern on the resist film An exposure process for developing and a development process for developing the exposed resist film are sequentially performed to form a predetermined resist pattern on the wafer. Using this resist pattern as a mask, the wafer is etched, and then the resist film is removed to form a predetermined pattern on the wafer. Thus, the process of forming a predetermined pattern in a predetermined layer is repeated a plurality of times, and a semiconductor device having a multilayer wiring structure is manufactured.

  Incidentally, in the semiconductor device manufacturing process as described above, for example, the wafer W may be subjected to a modification process by irradiating the wafer with ultraviolet rays. For this modification treatment, for example, an ultraviolet irradiation device as shown in Patent Document 1 is used.

  This ultraviolet irradiation device has a stage provided in the processing chamber and an ultraviolet irradiation unit provided above the stage. In this ultraviolet irradiation apparatus, ultraviolet rays are irradiated from an ultraviolet irradiation section to an object to be processed placed on a stage while supplying a processing gas into the processing chamber. In addition, in this ultraviolet irradiation device, in order to reduce the amount of the ultraviolet rays irradiated from the ultraviolet irradiation unit absorbed by the oxygen in the processing container, other processing for exciting oxygen by irradiating the processing gas with ultraviolet rays in advance. A chamber is provided, and a processing gas irradiated with ultraviolet rays in another processing chamber is supplied into the processing chamber.

JP 2011-251228 A

  In recent years, a method of removing an organic film such as an SOC (Spin On Carbon) film or an SOG (Spin On Glass) film formed on a wafer by ultraviolet irradiation instead of dry etching has been used. In this method, for example, active oxygen and ozone are generated in a processing atmosphere by irradiating ultraviolet rays having a wavelength of 172 nm, and the surface of the organic film is decomposed and removed by the active oxygen and ozone.

  By the way, the illuminance of the irradiated ultraviolet light is attenuated to about 76% when the distance from the irradiated surface is 1 mm away at atmospheric pressure, and to about 44% when 3 mm away. Therefore, when using ultraviolet irradiation for removing the organic film, the distance between the irradiation surface and the wafer is maintained at, for example, about 1 mm.

  However, when the gap is as small as about 1 mm, the variation in the illuminance of ultraviolet rays is not relaxed, and it is difficult to perform uniform processing. Further, in order to suppress the attenuation of ultraviolet rays due to oxygen, for example, ultraviolet rays may be irradiated in a reduced pressure atmosphere. However, in order to reduce the pressure of the entire processing chamber as disclosed in Patent Document 1, for example, a large exhaust device is required. become. Moreover, since it takes time to reduce the pressure in the processing chamber to a desired pressure, there is a problem in that throughput is reduced.

  This invention is made | formed in view of this point, and it aims at irradiating an ultraviolet-ray uniformly in a substrate surface.

In order to achieve the above object, the present invention provides an ultraviolet irradiation device for irradiating the surface of a substrate with ultraviolet rays, comprising: a substrate holding portion for holding a substrate on an upper surface; and a light source for irradiating ultraviolet rays, Sandwiching the ultraviolet irradiation chamber, an ultraviolet irradiation chamber formed so as to face the transfer port, an exhaust mechanism for exhausting and depressurizing the ultraviolet irradiation chamber, a pre-irradiation standby unit for waiting the substrate holding unit, and the ultraviolet irradiation chamber The post-irradiation retracting part provided on the opposite side of the pre-irradiation standby part and the substrate holding part are interposed between the pre-irradiation standby part, the ultraviolet irradiation chamber, and the post-irradiation retracting part via the transfer port. a holding unit transport mechanism for moving Te has a gas supply mechanism for introducing a process gas into the UV irradiation chamber, the process gas, oxygen gas, ammonia gas, water vapor, at least one of methanol or ethanol One is a gas containing the light source, the substrate holder is arranged to extend in a direction perpendicular to the direction of movement, is a long elongated lamp than the diameter of the substrate, of the UV irradiation chamber The width in the direction orthogonal to the direction in which the lamp extends is smaller than the diameter of the substrate.

  According to the present invention, the pre-irradiation standby unit and the post-irradiation retracting unit are provided across the ultraviolet irradiation chamber, and the substrate holding unit that holds the substrate by the holding unit transport mechanism includes the ultraviolet irradiation chamber, the pre-irradiation standby unit, and the post-irradiation unit. Since it can be moved between the retracting portions, the entire surface of the substrate can be irradiated with ultraviolet rays by traversing the substrate holding portion across the ultraviolet irradiation chamber. Since the ultraviolet irradiation chamber can be depressurized by the exhaust mechanism, the attenuation of the ultraviolet rays in the ultraviolet irradiation chamber can be suppressed. Therefore, a predetermined interval can be secured between the light source and the substrate, and variations in illuminance of the light source can be reduced. As a result, it is possible to uniformly irradiate the substrate surface with ultraviolet rays and perform uniform processing within the substrate surface. Here, since the width of the ultraviolet irradiation chamber is smaller than the diameter of the substrate, the volume in the ultraviolet irradiation chamber can be reduced. Therefore, the inside of the ultraviolet irradiation chamber can be depressurized to a desired pressure without providing a large exhaust mechanism. In addition, since the time required to reduce the pressure inside the ultraviolet irradiation chamber to a desired pressure can be reduced, a reduction in throughput can be minimized.

On the upper surface of the substrate holding portion, a recessed portion that is recessed downward to accommodate the substrate is formed,
The recess may have a depth such that the height of the upper end surface of the substrate holding portion is the same as the height of the upper end surface of the substrate held in the recess.

  The transfer port on the pre-irradiation standby unit side of the ultraviolet irradiation chamber and the other transfer port on the post-irradiation retracting unit side of the ultraviolet irradiation chamber may have the same shape.

  The substrate holding unit may include a heating mechanism for heating the substrate.

  According to another aspect of the present invention, there is provided a substrate processing method using the ultraviolet irradiation device, wherein the ultraviolet irradiation chamber is depressurized by an exhaust mechanism, and the substrate holding unit is irradiated from the standby unit before irradiation. It is characterized by irradiating the entire surface of the substrate with ultraviolet rays by moving it to the rear retracting portion and passing under the light source.

  According to the present invention, it is possible to uniformly irradiate ultraviolet rays over the entire surface of the substrate.

It is a top view which shows the outline of a structure of the substrate processing system concerning this Embodiment. It is a side view which shows the outline of the internal structure of the substrate processing system concerning this Embodiment. It is a side view which shows the outline of the internal structure of the substrate processing system concerning this Embodiment. It is a cross-sectional view which shows the outline of a structure of an ultraviolet irradiation device. It is a longitudinal cross-sectional view which shows the outline of a structure of an ultraviolet irradiation device. It is explanatory drawing which showed the state of the wafer before processing with a film-forming system. It is explanatory drawing which showed the state of the wafer in each process of a film-forming process, (a) shows a mode that the organic material was apply | coated on the wafer, (b) is a 1st heat processing performed, and on a wafer (C) shows a state in which the organic film is formed, (c) shows a state in which the surface of the organic film is removed by performing the first ultraviolet irradiation process, and (d) shows a wafer in which the second heat treatment is performed. It shows a state in which an organic film is formed on the top, (e) shows a state in which the surface of the organic film has been removed by performing a second ultraviolet irradiation treatment, and (f) has performed an n-th ultraviolet irradiation treatment. A state where the surface of the organic film is removed is shown, and (g) a state where a predetermined organic film is formed on the wafer. It is explanatory drawing about a ultraviolet irradiation and the production | generation of active oxygen. It is a cross-sectional view which shows the outline of a structure of the ultraviolet irradiation device concerning other embodiment.

Embodiments of the present invention will be described below. FIG. 1 is a plan view showing an outline of a configuration of a substrate processing system 1 according to the present embodiment. 2 and 3 are side views showing an outline of the internal configuration of the substrate processing system 1. In the substrate processing system 1 of the present embodiment, a case where an organic film that is an SOC film is formed on a wafer W as a substrate will be described. A predetermined pattern such as a SiO ₂ film is formed in advance on the wafer W processed by the substrate processing system 1.

  As shown in FIG. 1, the substrate processing system 1 carries in / out a plurality of, for example, 25 wafers W between the outside and the substrate processing system 1 in a cassette unit, and carries in / out the wafers W to / from the cassette C. The cassette station 2 and the processing station 3 including a plurality of processing apparatuses that perform predetermined processing on the wafer W are integrally connected.

  The cassette station 2 is provided with a cassette mounting table 10. The cassette mounting table 10 can mount a plurality of cassettes C in a row in the X direction (vertical direction in FIG. 1). That is, the cassette station 2 is configured to be capable of holding a plurality of wafers W.

  The cassette station 2 is provided with a wafer transfer body 12 that can move on a transfer path 11 extending in the X direction. The wafer transfer body 12 is also movable in the vertical direction and around the vertical direction (θ direction), and can transfer the wafer W between the cassette C and the processing station 3.

  The processing station 3 is provided with a wafer transfer device 20 at the center thereof. Around the wafer transfer device 20, for example, four processing blocks G1 to G4 in which various processing devices are arranged in multiple stages are arranged. On the front side of the processing station 3 (X direction negative direction side in FIG. 1), the first processing block G1 and the second processing block G2 are sequentially arranged from the cassette station 2 side. A third processing block G3 and a fourth processing block G4 are arranged in this order from the cassette station 2 side on the back side of the processing station 3 (positive side in the X direction in FIG. 1). A delivery device 21 for delivering the wafer W is disposed on the cassette station 2 side of the processing station 3. The wafer transfer device 20 can transfer the wafer W to various processing devices (described later) arranged in these processing blocks G1 to G4 and the delivery device 21.

  In the first processing block G1, as shown in FIG. 2, a plurality of liquid processing apparatuses, for example, coating processing apparatuses 30 and 31 for applying an organic material for forming an organic film on the wafer W are arranged in two stages from the bottom. It is piled up. Similarly, in the second processing block G2, the coating processing apparatuses 32 and 33 are stacked in two stages in order from the bottom. In these coating treatment apparatuses 30 to 33, for example, spin coating for coating an organic material on the wafer W is performed. In spin coating, for example, an organic material is discharged onto the wafer W from an application nozzle, and the wafer W is rotated to diffuse the organic material to the surface of the wafer W. In addition, chemical chambers 34 and 35 for supplying organic materials to the coating processing apparatuses 30 to 33 are provided at the lowermost stages of the first processing block G1 and the second processing block G2, respectively. The organic material is, for example, a liquid obtained by dissolving a composition of an SOC film, which is an organic film, in a predetermined solvent.

  In the third processing block G3, as shown in FIG. 3, ultraviolet irradiation apparatuses 40, 41, and 42 that perform ultraviolet irradiation processing on the wafer W, a heat treatment apparatus 43 that heat-processes the wafer W, and the temperature of the wafer W are adjusted. For example, the temperature adjusting devices 44 are stacked in five stages in order from the bottom.

  In the fourth processing block G4, similarly to the third processing block G3, the ultraviolet irradiation devices 50, 51, 52, the heat treatment device 53, and the temperature control device 54 are stacked in five stages in order from the bottom.

Next, the structure of the ultraviolet irradiation devices 40 to 42 and 50 to 52 described above will be described. The ultraviolet irradiation device 40 has a housing 100 as shown in FIGS. 4 and 5. A loading / unloading port (not shown) for the wafer W is formed on the side surface of the housing 100 on the wafer transfer device 20 side, and an opening / closing shutter (not shown) is provided at the loading / unloading port.
The housing may be open at the top.

  In the casing 100, a wafer holding mechanism 101 as a substrate holding unit that holds the wafer W by suction and an ultraviolet irradiation chamber 103 including a light source 102 that emits ultraviolet light are provided. On the bottom surface of the housing 100, two guides extending in parallel from one end side (the X direction negative direction side in FIG. 4) to the other end side (the X direction positive direction side in FIG. 4) in the housing 100. Rails 104, 104 are provided. The wafer holding mechanism 101 is provided on the guide rails 104 and 104, and can be freely moved on the guide rails 104 and 104 by a holding part transport mechanism 105 provided on the wafer holding mechanism 101.

  The ultraviolet irradiation chamber 103 is disposed in the vicinity of the central portion of the housing 100. Transport ports 110 and 111 through which the wafer holding mechanism 101 passes are formed on the side surfaces of the ultraviolet irradiation chamber 103 on the positive side in the X direction and the negative direction side in the X direction. In other words, the transfer ports 110 and 111 are openings larger than the cross section of the wafer holding mechanism 101, and are arranged to face the positions corresponding to the guide rails 104 and 104.

  The light source 102 provided in the ultraviolet irradiation chamber 103 is a long lamp longer than the diameter of the wafer W, for example. The light source 102 is arranged in the vicinity of the center of the ceiling surface of the ultraviolet irradiation chamber 103 so as to extend in a direction orthogonal to the guide rails 104 and 104 in plan view. The installation height of the light source 102 is adjusted so that the distance from the irradiation surface of the light source 102 to the wafer holding mechanism 101 is a predetermined length, for example, 6.5 mm in this embodiment. The wavelength of ultraviolet rays emitted from the light source 102 is, for example, 172 nm. In the illustrated example, the light source 102 is supported and provided on the ceiling surface of the ultraviolet irradiation chamber 103, but the light source 102 is placed on a glass window (not shown) provided on the ceiling surface of the ultraviolet irradiation chamber 103. It may be provided. In such a case, the ultraviolet rays irradiated from the ultraviolet irradiation unit 142 enter the processing container 130 through the glass window.

  The width in the direction in which the guide rails 104 and 104 extend in the ultraviolet irradiation chamber 103 is configured to be smaller than the diameter of the wafer W. In addition, the width of the ultraviolet irradiation chamber 103 in the direction orthogonal to the direction in which the guide rails 104 and 104 extend is larger than the diameter of the wafer W, and more specifically, a size that allows the wafer holding mechanism 101 to pass therethrough. Yes. Therefore, when irradiating the wafer W with ultraviolet rays, the wafer holding mechanism 101 holding the wafer W is moved along the guide rails 104 and 104 to cross the lower part of the light source 102.

  In addition, a region on the negative side in the X direction outside the ultraviolet irradiation chamber 103 in the housing 100 is configured wider than the wafer holding mechanism 101 in a plan view, and a pre-irradiation standby unit that waits for the wafer W before ultraviolet irradiation. It functions as 106. That is, the pre-irradiation standby unit 106 can make the wafer holding mechanism 101 stand by in a state where the entire surface of the wafer W is located outside the ultraviolet irradiation chamber 103. In addition, a region located on the opposite side of the pre-irradiation standby unit 106 with the ultraviolet irradiation chamber 103 interposed therebetween is also configured wider than the wafer holding mechanism 101. This region functions as a post-irradiation retracting unit 107 that causes the wafer holding mechanism 101 to stand by in a state where the entire surface of the wafer W irradiated with ultraviolet rays across the light source 102 is positioned outside the ultraviolet irradiation chamber 103. Therefore, when irradiating the entire surface of the wafer W with ultraviolet rays, the wafer holding mechanism 101 is made to wait in the pre-irradiation standby unit 106 in a state where the entire surface of the wafer W is located outside the ultraviolet irradiation chamber 103, and then the wafer holding mechanism 101 Is moved toward the retracting portion 107 after irradiation. Then, the end of the wafer W after irradiation 107 (the end on the X direction positive direction side in FIG. 4) to the end of the wafer W on the standby side 106 before irradiation (the end on the X direction negative direction side in FIG. 4). ), The entire surface of the wafer W is irradiated with ultraviolet rays.

  In addition, an exhaust mechanism 120 that exhausts the inside of the ultraviolet irradiation chamber 103 and depressurizes it is connected to the ceiling surface of the ultraviolet irradiation chamber 103 on the side of the light source 102, for example, the post-irradiation retractor 107 via an exhaust pipe 121. Yes. A gas supply mechanism 122 that introduces a processing gas into the ultraviolet irradiation chamber 103 is connected via a gas supply pipe 123 to the ceiling surface opposite to the exhaust pipe 121 across the light source 102. The gas supply pipe 123 is provided with a supply device group 124 including a valve for controlling the flow of the processing gas, a flow rate adjusting mechanism, and the like. The processing gas in the present embodiment is a gas containing oxygen gas, for example. However, when a gas containing oxygen is supplied into the ultraviolet irradiation chamber 103, the gas supply mechanism 122 may not be provided, and an opening for sucking air into the ceiling surface may be formed instead of the gas supply pipe 123. Further, when the wafer holding mechanism 101 holding the wafer W passes through the transfer ports 110 and 111, the air is also sucked from the gap formed between the transfer ports 110 and 111 and the wafer holding mechanism 101. It is not always necessary to provide the opening itself. In such a case as well, by reducing the pressure inside the ultraviolet irradiation chamber 103 by the exhaust mechanism 120, the atmosphere that is a gas containing oxygen can be introduced into the ultraviolet irradiation chamber 103 from the outside of the ultraviolet irradiation chamber 103. Further, the exhaust pipe 121 and the gas supply pipe 123 are not necessarily arranged on the ceiling surface of the ultraviolet irradiation chamber 103, and their connection positions can be arbitrarily set as long as the interior of the ultraviolet irradiation chamber 103 can be set to a desired atmosphere.

  The wafer holding mechanism 101 is configured to be larger than the diameter of the wafer W, and is configured in a substantially rectangular shape having a predetermined thickness. On the upper surface of the wafer holding mechanism 101, a dent 101a that is larger than the diameter of the wafer W and is recessed downward is formed, and the wafer W can be accommodated in the dent 101a. A plurality of suction ports (not shown) are formed on the bottom surface of the recess 101a, and the wafer W can be sucked and held by the suction ports. A plurality of gap pins 130 are provided on the bottom surface of the recess 101a. The recess 101 a has a depth such that the height of the upper end surface of the wafer W held by the wafer holding mechanism 101 is the same as the height of the upper end surface of the wafer holding mechanism 101. Therefore, when the wafer holding mechanism 101 holding the wafer W passes through the transfer ports 110 and 111, the shape of the gap formed between the transfer ports 110 and 111 and the wafer holding mechanism 101 is kept constant. Can do. Therefore, when the holding mechanism 101 passes through the transport ports 110 and 111, fluctuations in the amount of air sucked from the gap can be suppressed to a minimum. As a result, the pressure in the ultraviolet irradiation chamber 103, the gas concentration, and in this embodiment, the oxygen concentration can be kept substantially constant.

  The wafer holding mechanism 101 has a built-in heater 131 as a heating mechanism, and the held wafer W can be heated to a predetermined temperature.

  Below the pre-irradiation standby unit 106, for example, at a position where the wafer holding mechanism 101 delivers the wafer W to and from the wafer transfer device 20, lift pins 132 for supporting and lifting the wafer W from below are provided. For example, three are provided. The lifting pins can be moved up and down by a lifting mechanism (not shown). Near the center of the wafer holding mechanism 101, through holes 133 that penetrate the wafer holding mechanism 101 in the thickness direction are formed, for example, at three locations. The elevating pins 132 are inserted through the through holes 133 and can protrude from the upper surface of the wafer holding mechanism 101.

  The configurations of the ultraviolet irradiation devices 41, 42, and 50 to 52 are the same as the configuration of the ultraviolet irradiation device 40 described above, and thus the description thereof is omitted.

  The substrate processing system 1 is provided with a control unit 200 as shown in FIG. The control unit 200 is a computer, for example, and has a program storage unit (not shown). The program storage unit stores a program for executing the film forming process in the substrate processing system 1. The program is recorded on a computer-readable storage medium H such as a computer-readable hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical desk (MO), or a memory card. May have been installed in the control unit 200 from the storage medium H.

  The substrate processing system 1 according to the present embodiment is configured as described above. Next, a process for forming an organic film performed in the substrate processing system 1 will be described. FIG. 6 shows the state of the wafer W before being processed by the substrate processing system 1, and FIG. 7 shows the state of the wafer W in each step of the wafer processing.

On the wafer W processed by the substrate processing system 1, a predetermined pattern P such as a SiO ₂ film is formed in advance as shown in FIG. The pattern P is formed sparsely and densely on the wafer W, and the recess portion of the pattern P is not formed on the wafer W. The first region A in which the film (pattern P) covers the surface of the wafer W and the pattern A second region B in which a depression Q is formed between P and P is formed. That is, the first area A is a so-called blanket area, and the second area B is an area where, for example, a line and space pattern P is formed.

  First, the wafer W is taken out from the cassette C on the cassette mounting table 10 by the wafer transfer body 12 and transferred to the delivery device 21 of the processing station 3. Thereafter, the wafer W is transferred to the temperature adjustment device 44 by the wafer transfer device 20, and the temperature is adjusted to a predetermined temperature.

  Thereafter, the wafer W is transferred to the coating processing apparatus 30 by the wafer transfer apparatus 20. The wafer W carried into the coating treatment apparatus 30 is coated with an organic material on the wafer W by spin coating (step S1).

At this time, as shown in FIG. 7A, due to the surface tension and viscosity of the organic material L applied on the wafer W, the organic material L in the second region B (hereinafter referred to as “organic material L _B ”). Is recessed compared to the organic material L in the first region A (hereinafter referred to as “organic material L _A ”). That is, the height _{H B1} from the pattern P the surface of the organic material _{L B} is lower than the height _{H A1} from pattern P the surface of the organic material _{L A.} Then, step _{D 1} occurs between the organic material _{L A} and an organic material _{L B.}

Thereafter, the wafer W is transferred to the ultraviolet irradiation device 40 by the wafer transfer device 20. At this time, the wafer holding mechanism 101 stands by in the pre-irradiation standby unit 106. The wafer W carried into the ultraviolet irradiating device 40 is first transported above the wafer holding mechanism 101 and transferred to the lift pins 132 that have been lifted and waited in advance. Subsequently, the lift pins 132 are lowered, and the wafer W is placed on the gap pins 130 of the wafer holding mechanism 101 and held by suction. The wafer W on the wafer holding mechanism 101 is heated to a predetermined temperature, for example, 300 ° C. by the heater 131. When the wafer W is heated for a predetermined time, the organic material L on the wafer W is heated, and an organic film F is formed on the wafer W as shown in FIG. 7B (step S2). The organic film F in the first region A (hereinafter may be referred to as “organic film F _A ”) and the organic film F in the second region B (hereinafter referred to as “organic film F _B ”). ) between the stepped D ₁ is generated as described above.

  Next, the wafer holding mechanism 101 moves to the ultraviolet irradiation chamber 103 side. At this time, the ultraviolet irradiation chamber 103 is supplied with a processing gas containing oxygen gas from the gas supply mechanism 122 in advance and exhausted by the exhaust mechanism 120 to a predetermined reduced pressure atmosphere, for example, 1 Pa in the present embodiment. Maintained. At this time, since the ultraviolet irradiation chamber 103 is narrower than the diameter of the wafer W, it can be reduced to a predetermined pressure in a short time. Then, the wafer W on the wafer holding mechanism 101 crosses below the light source 102, so that the entire surface of the wafer W is irradiated with ultraviolet rays. At this time, active oxygen and ozone are generated in the treatment atmosphere of the oxidizing gas in the ultraviolet irradiation chamber 103 by the irradiated ultraviolet rays. The surface of the organic film F is decomposed and removed by these active oxygen and ozone (step S3). That is, the organic film F is etched back.

  Here, generation of active oxygen and ozone by ultraviolet irradiation will be described in detail. For example, in order to increase the decomposition rate of the organic film F, it is preferable to increase the density of active oxygen particularly in the vicinity of the surface of the wafer W. However, since the lifetime of active oxygen is extremely short, not all of the active oxygen generated in the region between the wafer W and the light source reaches the vicinity of the surface of the wafer W, and most of the active oxygen is in the vicinity of the surface of the wafer W. Deactivate without reaching. Therefore, in order to increase the density of active oxygen near the surface of the wafer W, it is necessary to increase the amount of active oxygen generated near the surface of the wafer W. However, since ultraviolet rays are absorbed and attenuated by oxygen in the atmosphere, in order to secure a sufficient amount of ultraviolet rays in the vicinity of the surface of the wafer W, for example, it is conceivable to increase the illuminance of ultraviolet rays from a light source. There is a limit. For this reason, conventionally, a measure has been taken to reduce the distance between the wafer W and the light source to, for example, about 1 mm. However, when the distance between the wafer W and the light source 102 is reduced, it is difficult to perform uniform processing over the entire surface of the wafer W due to variations in the illuminance of ultraviolet rays.

  Therefore, the present inventors have intensively studied and arrived at the point that the amount of active oxygen reaching the wafer W can be increased without increasing the illuminance of ultraviolet rays by irradiating ultraviolet rays in a reduced pressure atmosphere. did. That is, the lifetime of the active oxygen is approximately the same as the time required for moving through the mean free process, and the average free process of the active oxygen, that is, the life is extended by irradiating ultraviolet rays in a reduced pressure atmosphere, and as a result, reaches the wafer W. The amount of active oxygen increases.

  More specifically, for example, as shown in FIG. 8, most of the active oxygen generated in the region U separated from the surface of the wafer W by a distance equal to or greater than the mean free process is deactivated without reaching the wafer W. Here, for example, the mean free path of active oxygen under atmospheric pressure is about 65 nm, for example, and therefore the region U that is more than 65 nm away from the wafer W only attenuates ultraviolet rays from the light source 102, and the organic film F is decomposed. Does not contribute. In such a case, the active oxygen generated by the ultraviolet rays that have reached the region V within the range of the mean free process from the wafer W contributes to the decomposition of the organic film F. However, since the ultraviolet rays that reach the region V are greatly attenuated in the region U, the active oxygen generated in the region V is also greatly reduced compared to the region U. Therefore, for example, even if the distance between the light source and the wafer W is set to 1 mm as in the prior art, most of the ultraviolet rays are still absorbed in the region U and attenuated. For this reason, it is preferable to set the distance between the light source 102 and the wafer W to be equal to or less than the mean free path. However, it is extremely difficult to adjust the distance between the light source 102 and the wafer W in the nano order, which is not practical.

  Therefore, for example, when the pressure in the ultraviolet irradiation chamber 103 is reduced to about 1 Pa, which is about 1 / 100,000 of atmospheric pressure, the mean free path becomes 6.5 mm, which is about 100,000 times. Therefore, when the distance from the irradiation surface of the light source 102 to the surface of the wafer W is set to 6.5 mm as in the present embodiment, the distance equal to or greater than the mean free process is separated from the surface of the wafer W shown in FIG. The region U does not exist. Then, most of the active oxygen generated by the ultraviolet rays irradiated from the light source 102 reaches the surface of the wafer W without being deactivated. In such a case, for example, the same effect as when the distance between the light source and the wafer W is set to 65 nm under atmospheric pressure can be obtained. Therefore, in the present embodiment, even if the illuminance of ultraviolet rays from the light source 102 is the same as the conventional one, the amount of active oxygen that reaches the wafer W increases dramatically, and the organic film F is etched back by active oxygen. Can be done efficiently.

  Further, since the distance between the wafer W and the light source 102 is set to 6.5 mm, which is wider than the conventional 1 mm, the variation in the illuminance of the light source 102 can be alleviated and the wafer W surface can be uniformly irradiated with ultraviolet rays. Thereby, the etching amount of the organic film F in the wafer W surface can be made uniform.

  Further, the recess 101 a of the wafer holding mechanism 101 allows the shape of the gap formed between the transfer ports 110 and 111 and the wafer holding mechanism 101 to be constant when the wafer holding mechanism 101 passes through the transfer ports 110 and 111. Thus, the pressure in the ultraviolet irradiation chamber 103 is kept substantially constant. As a result, the etching process of the organic film F is stably performed.

In this way, the surface of the organic film F is removed by irradiating the ultraviolet light from the light source 102 while heating the organic film F by the wafer holding mechanism 101 in the ultraviolet processing chamber 103 under a reduced pressure atmosphere. Then, as shown in FIG. 7C, the surface of the organic film F is removed to a predetermined depth at which the organic film F _A is completely removed, that is, the surface of the organic film F having a height H _A1 is removed. The Then, to expose the surface of the pattern P, the first area A is absent organic film _{F A,} the height within the recess Q of the pattern P in the second region B _H C1 _{(= H} A1 -H the organic layer _{F B} of _B1) remains.

  Note that when the ultraviolet treatment is performed in the ultraviolet irradiation chamber 103, the surface of the organic film F can be efficiently removed in a short time by heating the organic film F. For example, when the surface of the organic film F at room temperature (23 ° C.) is removed by 100 nm, it is necessary to perform the ultraviolet irradiation treatment for 10 minutes, while the organic film F is heated at 300 ° C. as in the present embodiment. When the surface of the organic film F is removed by 100 nm, the ultraviolet irradiation process only needs to be performed for 30 seconds.

  The wavelength of the ultraviolet light emitted from the light source is not particularly limited, but is preferably 172 nm as in the present embodiment. The shorter the wavelength of the ultraviolet light, the greater the power when performing the ultraviolet irradiation treatment, and the surface of the organic film F can be efficiently removed. On the other hand, ultraviolet rays having a short wavelength are easily absorbed and attenuated by substances present in the atmosphere. However, by reducing the ultraviolet irradiation chamber 103 to a reduced pressure atmosphere as in this embodiment, the ultraviolet rays from the light source 102 are attenuated. Therefore, the wavelength of the ultraviolet light is preferably 172 nm.

  Thereafter, the wafer W is transferred to the temperature adjustment device 44 by the wafer transfer device 20, and the temperature is adjusted to a predetermined temperature.

  As described above, the coating process of the organic material L on the wafer W in the process S1, the heating process of the organic material L on the wafer W in the process S2, and the surface removal process of the organic film F on the wafer W in the process S3 are sequentially performed. As a result, the organic film F is formed on the wafer W. And these processes S1-S3 are performed in multiple times, for example, n times. In addition, although temperature control of the wafer W is performed in the temperature control apparatuses 44 and 54 after each process S3, description is abbreviate | omitted below.

  Next, the second steps S1 to S3 will be described. The second processes S1 to S3 are the same processes as the first processes S1 to S3, respectively, and only the main points will be described in the following description.

In the second step S <b> 1, the organic material L is applied onto the wafer W in the coating processing apparatus 31. In the second step S1, the organic material L is applied with a smaller film thickness than in the first step S1. Then, as shown in FIG. 7D to be described later, the heights H _A2 and H _B2 of the second organic films F _A and F _B (organic materials L _A and L _B ) are the first organic films F _A , It is smaller than the height _{H A1, H B1} of F _B.

Thereafter, in the second step S2, the organic material L on the wafer W is heated in the wafer holding mechanism 101 of the ultraviolet irradiation device 41, and an organic film F is formed on the wafer W as shown in FIG. The At this time, between the organic film F _A and the organic film F _B, step D ₂ is generated. However, minute with a reduced thickness of the organic material L in a second step S1, is smaller than the step D ₂ is the first described above step D _1.

Thereafter, in the second step S3, the wafer holding mechanism 101 irradiates the ultraviolet light from the light source 102 of the ultraviolet irradiation chamber 103 while heating the organic film F on the wafer W, as shown in FIG. The surface of the organic film F is removed. The surface of the organic film F is removed until the organic film F _A is completely removed, that is, the surface of the organic film F having a height H _A2 is removed. Then, there is no organic film _{F A} in the first region A, an organic film _{F B} of height in the recess Q of the pattern P in the second region _{B H C2 (= H A1 -H} B1) Remains. The height H _C2 of the organic film F _B remaining after the second process S3 is larger than that of the organic film F height H _C1 of _B remaining after the first step S3. That is, each successive number of steps S1 to S3, gradually accumulate organic film _{F B} to the recess Q of the pattern P.

Similar to the second step S1 to S3, the third to nth steps S1 to S3 are performed. Then, step _D 3 to D _n between the organic film _{F A} and the organic layer _{F B} is reduced, step _{D n} becomes almost zero in the end. Then, heights of the pattern P on the surface of the surface of the organic film F _B as shown in FIG. 7 (f) are the same.

  Thereafter, an organic material L having a predetermined film thickness is applied on the wafer W by the coating processing device 32, and the organic material L on the wafer W is heated by the heat treatment device 43. In this way, as shown in FIG. 7G, an organic film F having a predetermined film thickness and a flattened surface is formed on the wafer W.

  Thereafter, the wafer W is transferred to the delivery device 21 by the wafer transfer device 20 and returned to the cassette C by the wafer transfer body 12. Thus, a series of film forming processes in the substrate processing system 1 is completed.

  According to the above embodiment, the pre-irradiation standby unit 106 and the post-irradiation retracting unit 107 are provided across the ultraviolet irradiation chamber 103, and the wafer holding mechanism 101 holding the wafer W is moved by the holding unit transport mechanism 105 to the ultraviolet irradiation chamber. Can be irradiated with ultraviolet rays over the entire surface of the wafer W. At this time, since the inside of the ultraviolet irradiation chamber 103 is depressurized by the exhaust mechanism 120, the attenuation of the ultraviolet rays in the ultraviolet irradiation chamber 103 can be suppressed. Therefore, a predetermined distance between the light source 102 and the wafer W, in this embodiment, 6.5 mm, which is a distance approximately equal to the mean free path of active oxygen under the pressure of the ultraviolet irradiation chamber 103, can be secured. The variation in illuminance of 102 can be reduced. As a result, it is possible to uniformly irradiate the wafer W surface with ultraviolet rays and perform uniform processing within the wafer W surface. Here, since the width of the ultraviolet irradiation chamber 103 is smaller than the diameter of the wafer W, the volume in the ultraviolet irradiation chamber 103 can be reduced. Accordingly, the inside of the ultraviolet irradiation chamber 103 can be reduced to a desired pressure without providing a large exhaust mechanism 120. In addition, since the time required to reduce the pressure inside the ultraviolet irradiation chamber 103 to a desired pressure can be reduced, a reduction in throughput can be minimized.

  In addition, the recess 101 a of the wafer holding mechanism 101 allows the shape of the gap formed between the transfer ports 110 and 111 and the wafer holding mechanism 101 to be constant when the wafer holding mechanism 101 passes through the transfer ports 110 and 111. Kept. Therefore, the pressure in the ultraviolet irradiation chamber 103 is kept substantially constant, and the etching process of the organic film F is stably performed. In addition, it is preferable that the transfer ports 110 and 111 have the same shape. For example, the amount of the air sucked into the ultraviolet irradiation chamber 103 from the standby unit 106 before irradiation and the ultraviolet irradiation chamber 103 from the post-irradiation retreat unit 107 are preferable. Accordingly, the amount of the air sucked into the chamber can be equalized, and the occurrence of pressure bias in the ultraviolet irradiation chamber 103 can be prevented. As a result, the concentration of active oxygen in the ultraviolet irradiation chamber 103 can be made uniform, and the wafer W can be uniformly processed in the surface.

  Furthermore, since the wafer holding mechanism 101 includes the heater 131, the ultraviolet treatment can be performed while heating the wafer W and the organic film F. Therefore, the surface of the organic film F can be efficiently removed in a short time. The wafer W may be heated by, for example, heating a processing gas supplied from the gas supply mechanism 122. In such a case, the gas supply mechanism 122 or the gas supply pipe 121 may be provided with a heating mechanism for heating the processing gas.

  Note that the pre-irradiation standby unit 106 and the post-irradiation retracting unit 107 are wide enough to move the wafer holding mechanism 101 to a position where the wafer W is not irradiated with ultraviolet rays from the light source 102 of the ultraviolet irradiation chamber 103. The entire wafer holding mechanism 101 does not necessarily have a size that can be retracted outside the ultraviolet irradiation chamber 103. On the other hand, when the wafer holding mechanism 101 is retracted to a position where the wafer W is not irradiated with ultraviolet rays, a part of the wafer W holding mechanism enters the ultraviolet irradiation chamber 103 as shown in FIG. Thus, for example, the positions of the end portions of the guide rails 104, 104, the sizes of the standby unit 106 before irradiation and the retracting unit 107 after irradiation, and the size of the wafer holding mechanism 101 may be adjusted, or the holding unit moving mechanism 105 may be adjusted. The operation may be controlled. Note that FIG. 9 illustrates a state in which the end of the wafer holding mechanism 101 on the post-irradiation retracting portion 107 side is extended to the post-irradiation retracting portion 107 side. By setting a part of the wafer W holding mechanism to always enter the ultraviolet irradiation chamber 103, a gap is always formed between the transfer ports 110 and 111 and the wafer holding mechanism 101. Thereby, since the amount of air sucked into the ultraviolet irradiation chamber 103 side from the transfer ports 110 and 111 can be reduced, the inside of the ultraviolet irradiation chamber 103 can always be maintained in a predetermined reduced pressure state. Therefore, it is not necessary to wait for the pressure in the ultraviolet irradiation chamber 103 to drop each time the plurality of wafers W are irradiated with ultraviolet rays, and a decrease in throughput can be avoided.

  Further, from the viewpoint of reducing the amount of air sucked into the ultraviolet irradiation chamber 103 side from the transfer ports 110 and 111, it is preferable to make the gap between the transfer ports 110 and 111 and the wafer holding mechanism 101 as narrow as possible. Further, unevenness functioning as a labyrinth seal, for example, may be provided inside the transfer ports 110 and 111 to reduce the amount of air sucked from the transfer ports 110 and 111.

  In the above embodiment, the pre-irradiation standby unit 106 and the post-irradiation retracting unit 107 are surrounded by the housing 100. However, if the ultraviolet irradiation chamber 103 can be appropriately evacuated, the pre-irradiation standby unit 106 is provided. Since the post-irradiation retracting unit 107 may be in an atmospheric pressure state, the pre-irradiation standby unit 106 and the post-irradiation retracting unit 107 are not necessarily surrounded by the casing 100. In such a case, for example, positions corresponding to the pre-irradiation standby unit 106 and the post-irradiation retracting unit 107 above the housing 100 may be opened.

  In the above embodiment, the gas containing oxygen gas is supplied from the gas supply mechanism 122, but the gas supplied from the gas supply mechanism 122 can be arbitrarily set by a process performed by the ultraviolet irradiation device 103, for example, ammonia. Gas, water vapor, methanol, ethanol, or the like may be supplied. For example, by supplying a gas containing ammonia gas from the gas supply mechanism 122 and irradiating ultraviolet rays from the light source 102, nitrogen radicals can be generated, and for example, a nitride film can be formed on the surface of the wafer W. Further, by supplying water vapor, methanol, and ethanol, the surface of the wafer W can be oxidized to form, for example, an oxide film, or, for example, cleaning can be performed by oxidizing carbon that causes carbon contamination.

  In the above embodiment, the wafer holding mechanism 101 is a so-called vacuum chuck that holds the wafer W by a suction port. However, other mechanisms such as an electrostatic chuck may be used as long as the wafer W can be sucked and held. The reason why the wafer W is held by suction is to prevent the wafer W from being lifted or moved due to a pressure difference between the ultraviolet irradiation chamber 103, the pre-irradiation standby unit 106, and the post-irradiation retracting unit 107.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. It is understood.

DESCRIPTION OF SYMBOLS 1 Substrate processing system 30-33 Coating processing apparatus 40-42, 50-52 Ultraviolet irradiation apparatus 100 Case 101 Wafer holding mechanism 102 Light source 103 Ultraviolet irradiation chamber 104 Guide rail 105 Holding part conveyance mechanism 106 Pre-irradiation standby part 107 Retraction after irradiation Part 120 Exhaust mechanism 121 Exhaust pipe 122 Gas supply mechanism 123 Gas supply pipe 200 Control part A First region B Second region D Step F Organic film F _A (First region A) Organic film F _B (Second region) Organic film L in the region B) Organic material L _A Organic material in the first region A L _B Organic material in the second region B Pattern Q Indentation
U area V area W wafer

Claims (5)

An ultraviolet irradiation device that irradiates the surface of a substrate with ultraviolet rays,
A substrate holding unit for holding the substrate on the upper surface;
An ultraviolet light irradiation chamber provided with a light source for irradiating ultraviolet light, and having a transport opening through which the substrate holder passes,
An exhaust mechanism for exhausting and depressurizing the ultraviolet irradiation chamber;
A pre-irradiation standby unit for waiting the substrate holding unit;
A post-irradiation retracting part provided on the opposite side of the pre-irradiation standby part across the ultraviolet irradiation chamber,
A holding unit transport mechanism that moves the substrate holding unit through the transport port between the standby unit before irradiation, the ultraviolet irradiation chamber, and the post-irradiation retracting unit;
A gas supply mechanism for introducing a processing gas into the ultraviolet irradiation chamber ,
The processing gas is a gas containing at least one of oxygen gas, ammonia gas, water vapor, methanol or ethanol ,
The light source is a long lamp longer than the diameter of the substrate, which is arranged extending in a direction perpendicular to the direction in which the substrate holding unit moves,
The ultraviolet irradiation apparatus according to claim 1, wherein a width of the ultraviolet irradiation chamber in a direction orthogonal to a direction in which the lamp extends is smaller than a diameter of the substrate. On the upper surface of the substrate holding portion, a recessed portion that is recessed downward to accommodate the substrate is formed,
The recess portion has a depth such that a height of an upper end surface of the substrate holding portion is the same as a height of an upper end surface of the substrate held in the recess portion. Item 2. The ultraviolet irradiation device according to Item 1. The transport port on the pre-irradiation standby portion side of the ultraviolet irradiation chamber and the other transport port on the post-irradiation retracting portion side of the ultraviolet irradiation chamber have the same shape. UV irradiation device. The ultraviolet irradiation apparatus according to claim 1, wherein the substrate holding part includes a heating mechanism that heats the substrate. A substrate processing method using the ultraviolet irradiation device according to any one of claims 1 to 4 ,
The ultraviolet irradiation chamber is depressurized by an exhaust mechanism,
The substrate processing method of irradiating the entire surface of the substrate with ultraviolet rays by moving the substrate holding unit from the pre-irradiation standby unit to the post-irradiation retracting unit and passing under the light source.

Images