JP5159913B2 - Substrate coating method - Google Patents

Description

  The present invention relates to a method for coating a substrate such as a semiconductor wafer or a liquid crystal glass substrate (FPD substrate).

  Generally, in the manufacture of semiconductor devices, for example, a photolithography technique is used to form a circuit pattern by applying a resist solution to a semiconductor wafer, an FPD substrate or the like (hereinafter referred to as a wafer) and exposing the mask pattern. Has been. In this photolithography technique, a resist solution is applied to a wafer or the like by a spin coating method, the resist film formed thereby is exposed according to a predetermined circuit pattern, and this exposure pattern is developed to form a resist film. A circuit pattern is formed.

  In such a photolithography process, there is an increasing demand for increasing the exposure resolution with the recent miniaturization and thinning of device patterns. However, as the device pattern is further miniaturized, there is a problem that the resolution is reduced due to the interference effect in the resist layer and the in-plane line width accuracy is nonuniform.

  As a method for solving the above problem, an antireflection film is applied by supplying (applying) a water-soluble coating solution such as a TARC (Top Anti-Reflective Coating) chemical solution to the surface of a wafer or the like on which a resist layer is formed. A technique that can prevent interference in the resist layer is used. Further, the TARC chemical solution contains a surfactant having an action of reducing the free energy (interface tension) of the interface by the balance between the hydrophilic group and the hydrophobic group in the molecule.

  In general, in a coating processing method in which a coating solution is formed by supplying a coating solution to the surface of a wafer or the like, the coating solution is supplied from a nozzle to the center of the rotating wafer, and the coating solution is applied on the wafer by centrifugal force. A so-called spin coating method is often used in which a coating solution is applied on a wafer by diffusion. Further, in this spin coating method, as a method for uniformly coating a coating liquid in a small amount, for example, after supplying a solvent of the coating liquid onto the wafer and pre-wetting, the wafer is subsequently rotated to the first rotational speed. Accelerate and supply the coating liquid to the rotating wafer, then decelerate the wafer rotation speed to the second rotation speed to adjust the film thickness of the coating liquid on the wafer, and then rotate the wafer. There is known a method in which the coating liquid is accelerated again to the third rotational speed and the coating liquid on the wafer is shaken and dried (see, for example, Patent Document 1).

  When, for example, a water-soluble coating solution (TARC chemical solution) is applied to a wafer using the spin coating method, pure water is supplied onto the wafer as a solvent for the coating solution during prewetting.

Japanese Patent No. 3330324 (Claims)

  However, after supplying pure water as a solvent for the coating solution onto the wafer and pre-wetting it, the wafer rotation speed is subsequently accelerated to the first rotation speed, and then the wafer rotation speed is reduced to the second rotation speed. Then, since the surface tension value of pure water is very large, water drops for a moment immediately after spreading on a hydrophobic wafer, and the effect of prewetting is reduced. Therefore, there is a problem that when the TARC chemical solution is spin-coated, the water droplets are caused to cause a coating defect (uneven coating) of the coating film (TARC film).

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a substrate coating method capable of effectively using the coating liquid while eliminating waste of the coating liquid and making the coating liquid film uniform. With the goal.

  In order to solve the above problems, a substrate coating method according to the present invention is a method in which a water-soluble antireflection solution is applied to the surface of a substrate on which a resist film is formed before the pattern is exposed to the substrate. A substrate coating method for forming an antireflection film by holding a substrate to be processed on which a resist film is formed and rotating the substrate at a first rotational speed so that pure water is placed in the center of the substrate to be processed. Supplying a pure water reservoir, then supplying and mixing an antireflective solution to the pure water reservoir on the central position of the substrate to be processed, and then continuing the antireflection A step of diffusing the antireflection liquid by supplying the liquid at a second rotational speed and the antireflection liquid diffused over the entire surface of the substrate to be processed being higher than the first rotational speed and the second rotational speed. Drying at a lower rotational speed. The constitution (claim 1).

  In this invention, the time ratio between the mixing step and the diffusing step may be shorter, longer or the same as the mixing step time than the diffusing step time. , 3, 4).

  In the present invention, it is preferable that the first rotational speed is 10 rpm to 50 rpm. When the first rotational speed is lower than 10 rpm, the liquid pool (pure water paddle) does not spread to a desired size, and when the first rotational speed is higher than 50 rpm, the liquid pool (pure water paddle). ) Is too wide to maintain a circular state of a desired size.

  In the present invention, it is preferable that the second rotational speed is 2000 rpm to 4000 rpm. When the second rotational speed is lower than 2000 rpm, an uncoated region of the coating liquid on the substrate to be processed is generated. When the second rotational speed is higher than 4000 rpm, mist of the coating liquid is generated. This is because the generated mist may be reattached onto the coating liquid film and the coverage may be deteriorated.

  According to the present invention, the substrate to be processed on which the resist film is formed is held and rotated at the first rotational speed, and pure water is supplied to the central portion of the substrate to form a pure water pool, By supplying and mixing the antireflection liquid into the pure water pool on the center position of the substrate to be processed, the pure water becomes an intermediate layer between the substrate to be processed and the antireflection liquid when the antireflection liquid is supplied. The impact at the time of supply (during discharge) can be reduced. Then, while continuing to supply the antireflection liquid, the antireflection liquid is diffused by rotating at the second rotation speed, and the antireflection liquid diffused over the entire surface of the substrate is made higher than the first rotation speed by the second rotation speed. By drying at a lower rotational speed, the supply amount of the antireflection liquid can be reduced, and a uniform antireflection liquid film can be formed on the substrate to be processed.

  According to this invention, since it is configured as described above, it is possible to effectively use the coating liquid, reduce application defects (coating unevenness), and improve the uniformity of the coating liquid film. it can.

1 is a schematic plan view showing an entire processing system in which an exposure apparatus is connected to a coating / developing processing apparatus to which a coating processing apparatus according to the present invention is applied. It is a schematic front view of the said processing system. It is a schematic rear view of the processing system. It is a schematic longitudinal cross-sectional view which shows an example of the coating processing apparatus which concerns on this invention. It is a schematic cross-sectional view of the said coating processing apparatus. It is a flowchart which shows the main processes of the coating process in a coating processing apparatus. It is a graph which shows the rotation speed of the wafer in each process of a coating treatment process, and the supply timing of a coating liquid and a pure water. It is a schematic sectional drawing which shows typically the state of the liquid film on a wafer in each process of a coating treatment process. It is a graph which shows the state of the film thickness on a wafer by the rotation speed of a wafer in a coating film formation process.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic plan view showing an entire processing system in which an exposure apparatus is connected to a coating / developing processing apparatus to which the coating processing apparatus according to the present invention is applied, FIG. 2 is a schematic front view of the processing system, and FIG. FIG. 2 is a schematic rear view of the processing system.

  The processing system includes a carrier station 1 for carrying in and out a plurality of, for example, 25, semiconductor wafers W (hereinafter referred to as wafers W), which are substrates to be processed, and a carrier station 1 for taking in and out the carrier 10. A processing unit 2 that performs resist coating, development processing, and the like on the wafer W, an exposure apparatus 4 that performs immersion exposure on the surface of the wafer W in a state where an immersion layer that transmits light is formed on the surface of the wafer W, and the processing unit 2 And an interface unit 3 for transferring the wafer W.

  The carrier station 1 includes a mounting unit 11 on which a plurality of carriers 10 can be placed side by side, an opening / closing unit 12 provided on a front wall as viewed from the mounting unit 11, and a wafer from the carrier 10 via the opening / closing unit 12. Delivery means A1 for taking out W is provided.

  Further, a processing unit 2 surrounded by a casing 20 is connected to the back side of the carrier station 1, and the processing unit 2 is a processing unit in which heating / cooling units are arranged in multiple stages in order from the front side. Main transfer means A2 and A3 for transferring the wafer W between the units U1, U2 and U3 and the liquid processing units U4 and U5 are alternately arranged. The main transfer means A2 and A3 include one surface portion on the processing units U1, U2 and U3 side arranged in the front-rear direction when viewed from the carrier station 1, and one surface portion on the right liquid processing unit U4 and U5 side which will be described later. And a space surrounded by a partition wall 21 constituted by a rear surface portion forming one surface on the left side. Further, between the carrier station 1 and the processing unit 2 and between the processing unit 2 and the interface unit 3, a temperature / humidity provided with a temperature control device for the processing liquid used in each unit, a duct for temperature / humidity control, and the like. An adjustment unit 22 is arranged.

  The processing units U1, U2, and U3 are configured by laminating various units for performing pre-processing and post-processing of the processing performed in the liquid processing units U4 and U5 in a plurality of stages, for example, 10 stages. On the back side of the main transfer means A2, for example, an adhesion unit (AD) for hydrophobizing the wafer W and a heating unit (HP) for heating the wafer W are sequentially arranged from below as shown in FIG. Two levels are stacked. The adhesion unit (AD) may further include a mechanism for adjusting the temperature of the wafer W. A peripheral exposure device (WEE) 23 that selectively exposes only the edge portion of the wafer W is provided on the back side of the main transfer means A3. In addition, a heat treatment unit may be arranged on the back side of the main transfer unit A3 in the same manner as the back side of the main transfer unit A2.

  As shown in FIG. 3, the processing unit U <b> 1 is an oven-type processing unit that performs predetermined processing by placing the wafer W on the mounting table, for example, a high temperature that is a first heat processing unit that performs predetermined heat processing on the wafer W. Heat treatment unit (BAKE), high-precision temperature control unit (CPL) that performs cooling processing on wafer W under accurate temperature control, and transfer unit (TRS) that serves as a transfer unit for wafer W from transfer means A1 to main transfer means A2. ), And the temperature control unit (TCP) is stacked, for example, in ten steps from the top. In the processing unit U1, in the present embodiment, the third stage from the bottom is provided as a spare space. Also in the processing unit U2, for example, a post-baking unit (POST) as a fourth heat treatment unit, a pre-baking unit (PAB) which is a second heat treatment unit for heating the resist-coated wafer W, a high-precision temperature control unit ( CPL) are stacked, for example, in 10 steps from the top. Further, in the processing unit U3, for example, a post-exposure baking unit (PEB) and a high-precision temperature control unit (CPL) are stacked in, for example, 10 stages in order from the top as third heat treatment units for performing heat treatment on the exposed wafer W. Yes.

  Further, as shown in FIG. 2, for example, the liquid processing units U4 and U5 include a bottom antireflection film coating unit (BCT) 25 for coating an antireflection film on a chemical liquid storage section (CHM) such as a resist or a developer. , A top antireflection film coating unit (TCT) 26 having a coating processing apparatus according to the present invention, a resist coating unit (COT) 27 for coating a resist, and a developing unit for supplying a developing solution to the wafer W for developing processing ( DEV) 28 and the like are stacked in a plurality of stages, for example, five stages.

  As shown in FIG. 1, the interface unit 3 includes a first transfer chamber 3A and a second transfer chamber 3B that are provided between the processing unit 2 and the exposure apparatus 4 in the front-rear direction. A first wafer transfer unit 30A and a second wafer transfer unit 30B having arms that can move up and down and rotate about a vertical axis are provided.

  Note that the timing and time of the transfer of the wafer W by the first and second wafer transfer units 30A and 30B are controlled by a controller 60 mainly composed of a central processing unit (CPU) of a control computer as a control means. Yes.

  Further, in the first transfer chamber 3A, a buffer cassette 31 for temporarily storing a plurality of, for example, 25 wafers W is provided on the right side as viewed from the carrier station 1 side with the first wafer transfer unit 30A interposed therebetween, for example. They are stacked one above the other. The buffer cassette 31 may be arranged on the left side when viewed from the carrier station 1 side.

  Next, a procedure for processing the wafer W using the coating / developing apparatus will be described. Here, a case where a bottom antireflection film (BARC) is formed on the surface of the wafer W, a resist layer is applied thereon, and a top antireflection film is laminated on the surface of the resist layer will be described. First, the wafer W is taken out from the carrier 10 containing the wafer W by the transfer means A1, and the wafer W is transferred to the main transfer means A2 via the transfer unit (TRS) which constitutes one stage of the processing unit U1, and the coating process is performed. For example, a bottom antireflection film (BARC) is formed on the surface of the bottom antireflection film coating unit (BCT) 25 as a pretreatment. The wafer W on which the bottom antireflection film (BARC) is formed is transferred to the heat processing unit of the processing unit U1 by the main transfer means A2 and prebaked (BAKE).

  Thereafter, the wafer W is carried into a resist coating unit (COT) 27 by the main transfer means A2, and a resist is coated on the entire surface of the wafer W in a thin film shape. The wafer W to which the resist is applied is transferred to the heat processing section of the processing unit U2 by the main transfer means A2, and is pre-baked (PAB).

  Thereafter, a top antireflection film is formed on the surface of the resist layer of the wafer W by the top antireflection film coating unit (TCT) 26 by the main transfer means A2. The wafer W on which the top antireflection film is formed is transferred by the main transfer means A2 to the heat processing section of the processing unit U2 and prebaked (PAB).

  Thereafter, the wafer W is unloaded from the pre-bake unit (PAB) by the main transfer unit A3, transferred to the exposure apparatus 4 through the main transfer unit A3, the first and second wafer transfer units 30A, 30B, and exposure is performed.

  After that, the wafer W that has been exposed is carried into the post-exposure baking unit (PEB) of the processing unit U3 of the processing unit 2 through the second wafer transfer unit 30B and the first wafer transfer unit 30A. Here, when the wafer W is heated to a predetermined temperature, a post-exposure bake (PEB) process is performed in which the acid generated from the acid generator contained in the resist is diffused into the internal region. Then, when the resist component chemically reacts due to the catalytic action of the acid, the reaction region becomes soluble in the developer in the case of a positive type resist, for example.

  The wafer W that has been subjected to the PEB processing is carried into the developing unit (DEV) 28 by the main transport means A3, and the developing solution is supplied to the surface of the wafer W by the developing solution nozzle provided in the developing unit (DEV) 28 and developed. Processing is performed. Thus, a predetermined resist pattern is formed by dissolving a portion that is soluble in the developer in the resist film on the surface of the wafer W. Further, a rinsing liquid such as pure water is supplied to the wafer W for rinsing, and then spin drying is performed to shake off the rinsing liquid. Thereafter, the wafer W is unloaded from the developing unit (DEV) 28 by the main transfer unit A3, and is loaded into the post-baking unit (POST) of the processing unit U2 and subjected to heat treatment, and passes through the main transfer unit A2 and the transfer unit A1. Then, it is returned to the original carrier 10 on the mounting portion 11 and a series of coating / developing processes is completed.

  Next, the coating treatment apparatus according to the present invention will be described with reference to FIGS.

  FIG. 4 is a schematic longitudinal sectional view showing an example of a coating treatment apparatus according to the present invention, and FIG. 5 is a schematic transverse sectional view of the coating treatment apparatus. In the present embodiment, the coating liquid contains a surfactant applied on the wafer W on which the resist film is formed in order to form an antireflection film that prevents reflection of light during the exposure process. An antireflection film liquid material (TARC chemical) is used. The antireflection film liquid material as the coating liquid contains, for example, a water-soluble resin and a low molecular organic compound such as carboxylic acid or sulfonic acid.

  As shown in FIG. 4, the coating processing apparatus 40 includes a processing container 41, and a spin chuck 42 as a holding unit that holds and rotates the wafer W is provided in the center of the processing container 41. . The spin chuck 42 has a horizontal upper surface, and a suction port (not shown) for sucking the wafer W, for example, is provided on the upper surface. The wafer W can be sucked and held on the spin chuck 42 by suction from the suction port.

  The spin chuck 42 has a chuck drive mechanism 43 provided with a rotation mechanism such as a motor. The chuck drive mechanism 43 is electrically connected to a controller 60 having a central processing unit (CPU) as control means, and can rotate at a predetermined speed based on a control signal from the controller 60. Yes. Further, the chuck drive mechanism 43 is provided with an elevating drive source such as a cylinder, so that the spin chuck 42 can move up and down.

  Around the spin chuck 42, there is provided a cup 44 that receives and collects the liquid scattered or dropped from the wafer W. A drain line 45 for discharging the collected liquid and an exhaust line 46 for exhausting the atmosphere in the cup 44 are connected to the lower surface of the cup 44.

  As shown in FIG. 5, a guide rail 47 extending along the Y direction (left and right direction in FIG. 5) is formed on the negative side of the cup 44 in the X direction (downward direction in FIG. 5). The guide rail 47 is formed from, for example, the outer side of the cup 44 on the Y direction negative direction (left direction in FIG. 5) to the outer side on the Y direction positive direction (right direction in FIG. 5). First and second nozzle drive units 48a and 48b, which are first and second nozzle moving mechanisms, are movably mounted on the guide rail 47. The first and second nozzle drive units 48 a and 48 b are electrically connected to the controller 60 and are formed to be movable along the guide rail 47 based on a control signal from the controller 60.

  A first arm 49a is attached to the first nozzle drive unit 48a in the X direction, and a coating liquid is supplied to the first arm 49a as shown in FIGS. A liquid nozzle 50 is supported. In this case, the coating liquid nozzle 50 is formed to have a nozzle diameter that can discharge a small amount of the coating liquid, for example, a diameter of 0.8 mm. The first arm 49a is configured to be movable on the guide rail 47 by the first nozzle driving section 48a. As a result, the coating solution nozzle 50 can move from the standby unit 51 installed outside the cup 44 on the positive side in the Y direction to above the center of the wafer W in the cup 44, and further on the surface of the wafer W It can move in the radial direction of W. Further, the first arm 49a can be moved up and down by the first nozzle driving section 48a, and the height of the coating liquid nozzle 50 can be adjusted.

  As shown in FIG. 4, a coating liquid supply conduit 53 connected to a coating liquid supply source 52 is connected to the coating liquid nozzle 50. The coating liquid supply source 52 is formed by a bottle that stores the coating liquid, and the coating liquid is applied to the coating liquid nozzle 50 side by pressurizing a gas (N2 gas) supplied from a gas supply source, for example, an N2 gas supply source 54. Is supplied (pressure-feed). A filter 55, a pump 56, and a first on-off valve V1 having a flow rate adjusting function are provided in the coating liquid supply conduit 53 in this order from the coating liquid supply source 52 side. An on-off valve V3 is interposed in the N2 gas supply line 54a that connects the coating liquid supply source 52 and the N2 gas supply source 54.

  A second arm 49b is attached to the second nozzle drive section 48b in the X direction, and a pure water nozzle 57 for supplying a solvent of the coating solution, for example, pure water, to the second arm 49b. Is supported. The second arm 49b is movable on the guide rail 47 by the second nozzle driving section 48b shown in FIG. 5, and the pure water nozzle 57 is provided outside the Y direction negative side of the cup 44. It can be moved from the standby section 58 to above the center of the wafer W in the cup 44. Further, the second arm 49b can be raised and lowered by the second nozzle driving section 48b, and the height of the pure water nozzle 57 can be adjusted.

  As shown in FIG. 4, the pure water nozzle 57 is connected to a pure water supply pipe 59 a that is connected to a pure water supply source 59. Pure water is stored in the pure water supply source 58. The pure water supply pipe 59a is provided with a second on-off valve V2 having a flow rate adjusting function.

  The first and second on-off valves V1, V2 and the on-off valve V3 of the N2 gas supply line 54a are electrically connected to the controller 60, respectively, and open / close based on a control signal from the controller 60. It is like that.

  In the above configuration, the coating liquid nozzle 50 that supplies the coating liquid and the pure water nozzle 57 that supplies pure water are supported by separate arms, but are supported by the same arm and controlled by movement of the arms. The movement and supply timing of the coating liquid nozzle 50 and the pure water nozzle 57 may be controlled.

  The rotation operation and the vertical operation of the spin chuck 42 described above, the movement operation of the coating liquid nozzle 50 by the first nozzle driver 48a, the supply operation of the coating liquid nozzle 50 by the first on-off valve V1, the second nozzle The operation of the drive system such as the movement operation of the pure water nozzle 57 by the drive unit 48b and the pure water supply operation of the pure water nozzle 57 by the second on-off valve V2 is controlled by the controller 60. The controller 60 is configured by a computer including, for example, a CPU and a memory. For example, the resist coating process in the coating processing apparatus 40 can be realized by executing a program stored in the memory. Note that various programs for realizing the resist coating process in the coating processing apparatus 40 are, for example, a computer-readable hard disk (HD), flexible disk (FD), compact disk (CD), magnetic optical disk (MD), memory card. That is stored in the storage medium H and installed in the control unit 60 from the storage medium H is used.

  Next, a coating process performed by the coating apparatus 40 configured as described above will be described. FIG. 6 is a flowchart showing main steps of the coating process in the coating processing apparatus 40. FIG. 7 is a graph showing the rotation speed of the wafer W and the supply timing of the coating liquid and pure water in each step of the coating treatment process, and FIG. 8 is a schematic view of the state of the liquid film on the wafer in each step of the coating treatment process. FIG. Note that the length of the process time in FIG. 7 does not necessarily correspond to the actual length of time because priority is given to the ease of understanding the technology.

  The wafer W carried into the coating processing apparatus 40 is first sucked and held by the spin chuck 42. Subsequently, the pure water nozzle 57 of the standby unit 58 moves to above the center of the wafer W by the second arm 49b. Next, as shown in FIG. 4, the chuck driving mechanism 43 is controlled to rotate the wafer W by the spin chuck 42 at a first rotation speed of 10 rpm to 50 rpm, for example, 10 rpm in the present embodiment. Simultaneously with the rotation of the wafer W, pure water DIW is supplied from the pure water nozzle 57 to the center of the wafer W as shown in FIG. 8A (step S1 in FIGS. 6 and 7). When the wafer W is rotated at a low speed at the first rotation speed as described above, the pure water DIW supplied to the wafer W hardly diffuses on the wafer W, for example, about 0.5 mm to 4.0 mm of pure water. A liquid pool (pure water paddle PD) is formed. In addition, this process S1 is performed for 4 seconds, for example.

  When the supply of the pure water DIW is completed, the pure water nozzle 57 moves outward from the upper center of the wafer W, and the coating liquid nozzle 50 of the standby unit 51 moves to the upper center of the wafer W by the first arm 49a. To do.

  Thereafter, in a state of a first rotation speed, for example, 10 rpm, the antireflection liquid TARC (hereinafter referred to as the coating liquid TARC) is applied from the coating liquid nozzle 50 to the central portion of the wafer W as shown in FIG. 8B. A coating liquid is supplied (discharged) (step S2 in FIGS. 6 and 7). In this way, by supplying (discharging) the coating liquid TARC onto the pure water DIW, that is, the pure water paddle PD, in the state of the first rotational speed of the low-speed rotation of the wafer W, the coating liquid TARC is discharged by the pure water paddle PD. The impact can be reduced, and the concentration of the surfactant contained in the coating solution TARC can be reduced. Therefore, it is possible to suppress the generation of bubbles when supplying (discharging) the coating liquid TARC. In addition, this process S2 is performed for 0.5 second-1.5 second, for example, and 0.5 second in this Embodiment.

  As described above, when the coating liquid TARC is supplied (discharged) onto the pure water paddle PD to form a mixed layer in which the pure water DIW remains in the lower layer of the coating liquid TARC, as shown in FIG. The rotation of the wafer W is accelerated to the second rotation number, for example, 2000 rpm to 4000 rpm, and in this embodiment, 2000 rpm. During this time, the coating liquid TARC is continuously supplied from the coating liquid nozzle 50 as shown in FIG. Thus, when the wafer W is rotated at a high speed at the second rotational speed, the mixed layer PT diffuses over the wafer W, and the coating liquid TARC is guided by the mixed layer PT and diffuses over the wafer W to form a coating liquid film. (Step S3 in FIGS. 6 and 7). Since the mixed layer PT has a smaller contact angle with the resist film and better wettability than pure water DIW, the coating liquid TARC can diffuse smoothly and uniformly on the entire surface of the wafer W. At this time, even if bubbles are generated, they are extremely small and are blocked by pure water DIW, so that the adhesion probability on the wafer W is small and does not become uneven. In addition, this process S3 is performed for 0.5 second-1.5 second, and 1.5 second in this Embodiment.

  When the coating liquid TARC is diffused over the entire surface of the wafer W to form a coating liquid film, the rotation of the wafer W is decelerated to a third rotational speed, for example, 100 rpm as shown in FIG. Then, while the wafer W is rotating at the third rotational speed in this way, a force toward the center acts on the coating liquid TARC on the wafer W, and the coating liquid film on the wafer W is dried (adjusted) (FIG. 6). And step S4) of FIG. In addition, this process S4 is performed for 1 second, for example.

  When the film thickness of the coating liquid TARC on the wafer W is adjusted, as shown in FIG. 7, the rotation of the wafer W is accelerated to a fourth rotation speed, for example, 1000 to 2000 rpm, and in this embodiment, 1500 rpm. As a result, the coating liquid TARC diffused over the entire surface of the wafer W is dried to form a coating film (step S5 in FIGS. 6 and 7). In addition, this process S5 is performed for 10 seconds, for example.

  In the above embodiment, the case where the step (S2) of mixing the pure water DIW and the coating liquid TARC is 0.5 seconds and the step (S3) of forming the coating liquid film is 1.5 seconds is described ( However, as indicated by II in FIG. 7, the step S2 may be set to 1.0 second and the step S3 may be set to 1.0 second, or as indicated by III in FIG. As described above, the step S2 may be set to 1.5 seconds, and the step S3 may be set to 0.5 seconds. In this manner, the time ratio between the step (S2) of mixing the pure water DIW and the coating solution TARC and the step of forming the coating solution film (S3) is set to the step of mixing the pure water DIW and the coating solution TARC (S2). The step (S3) of forming the coating liquid film on the coating liquid TARC is controlled within the range of 1: 3 to 3: 1 (that is, S2: S3 = 1: 3 to 3: 1). The discharge amount can be set within a range in which the coating liquid film thickness can be formed uniformly.

  According to the above embodiment, the wafer W is rotated at a low first rotation speed to form the pure water paddle PD on the wafer W, and the coating liquid TARC is rotated in the first rotation speed. By supplying (discharging) the discharge impact of the coating liquid TARC can be reduced by the pure water paddle PD, and the pure water DIW and the coating liquid TARC are mixed while rotating the wafer W at the first low speed. By doing so, the concentration of the surfactant contained in the coating liquid TARC can be partially reduced. Thereby, generation | occurrence | production of the bubble at the time of supply (discharge) of the coating liquid TARC can be suppressed, and since application failure (application unevenness) can be reduced, the process of mixing the pure water DIW and the coating liquid TARC ( In S2), the coating liquid film can be spread uniformly.

  Further, according to the above-described embodiment, the wafer W is placed on the wafer W while supplying (discharging) the coating liquid TARC in a state where the coating liquid film is uniformly spread by the step (S2) of mixing the pure water DIW and the coating liquid TARC. The mixed layer PT on the wafer W is diffused at a high speed of 2 to diffuse, and the coating liquid TARC is led by the mixed layer PT to diffuse on the wafer W to form a coating liquid film. Thereby, the coating film can be made uniform with a small amount of coating liquid TARC.

  In the above embodiment, the case where the exposure apparatus is immersion exposure has been described. However, the coating processing method according to the present invention can also be applied to a coating / development processing apparatus that employs an exposure technique other than immersion exposure.

  Next, an experiment for evaluating the amount of rotation of the wafer W during the coating process (acceleration control) and the amount of coating liquid (antireflection liquid) TARC will be described.

First, a wafer subjected to an adhesion (ADH) process is prepared as a sample with poor coating properties of the coating liquid TARC. Next, in the case where the rotational speed of the wafer at the step of mixing the pure water DIW and the coating liquid TARC (S2) is 10 rpm, and the rotational speed of the wafer at the step of forming the coating liquid film (S3) is 2000 rpm, The time ratio between the step of mixing the water DIW and the coating solution TARC (S2) and the step of forming the coating solution film (S3) is the minimum ejection amount of the coating solution TARC that can ensure the formation of the coating film thickness (coverability). Based on the amount, as shown in Table 1, Table 2 and Table 3, 0.5 (second): 1.5 (second), 1.0 (second): 1.0 (second), 1.5 ( Seconds): 0.5 (seconds), in other words, the step (S3) of forming the coating liquid film with respect to the step (S2) of mixing the pure water DIW and the coating liquid TARC is 1: 3, 1: 1. , 3: 1.

The time ratios of the steps (S2) and (S3) are 0.5 (second): 1.5 (second) {Example 1}, 1.0 (second): 1.0 (second) {Example, respectively. 2}, 1.5 (seconds): 0.5 (seconds) When the coating performance of the coating film and the discharge amount of the coating liquid TARC were examined, the results shown in Table 4 were obtained. Obtained.

  As a result of the above evaluation, in Example 1, it was possible to ensure the formation of the coating film thickness (coverability) with a discharge amount of 1.8 ml of the coating liquid TARC, and in Example 2, the coating film with a discharge amount of 0.6 ml of the coating liquid TARC. Thickness formation (coverability) could be ensured, and in Example 3, formation of the coating film thickness (coverability) could be ensured with a discharge volume of 0.4 ml of the coating liquid TARC. Thus, in the first embodiment, the coating liquid TARC is supplied (discharged) onto the wafer at the current low-speed rotation, and is greatly discharged compared to the discharge amount of 5.0 ml to 6.0 ml in the case of the method of widening at the high-speed rotation. The amount could be reduced. Further, in Example 1, the uniformity (coating property) of the coating liquid film was poor when the discharge amount was 1.7 ml or less, but in Example 2, the uniformity of the coating liquid film was up to 0.6 ml. (Coating property) is good, and in Example 3, the uniformity (coating property) of the coating liquid film is good up to a discharge amount of 0.4 ml, and the discharge amount is further greatly reduced as compared with Example 1. I was able to.

  In the above evaluation experiment, the case where the rotation speed of the wafer at the step of forming the coating liquid film (S3) is 2000 rpm has been described. However, when the rotation speed of the wafer is 2000 rpm, 2500 rpm, 3000 rpm, and 4000 rpm, coating is performed on the wafer surface. When the film thickness distribution was examined by supplying (discharging) the liquid (discharge amount 0.5 ml), as shown in FIG. 9, there was almost no change in the film thickness when the rotation speed of the wafer was 2000 rpm, 2500 rpm, 3000 rpm, and 4000 rpm. Results were obtained. Thereby, it turned out that the rotation speed of the wafer at the time of the process (S3) of forming a coating liquid film should just be in the range of 2000 rpm-4000 rpm.

  In addition, when the rotation speed of the wafer is 1500 rpm, the film thickness is hardly changed from 2000 rpm to 4000 rpm, but an uncoated area is generated, and the coating limit is reduced by about 0.1 ml compared to 2000 rpm to 4000 rpm. To do. Further, when the rotation speed of the wafer becomes higher than 4000 rpm, mist of the coating liquid is generated, and the mist is reattached on the coating liquid film, which adversely affects the coating property.

  In the evaluation experiment, the case where the rotation speed of the wafer at the time of mixing the pure water DIW and the coating solution TARC (S2) is 10 rpm has been described. However, the rotation speed of the wafer is within the range of 10 rpm to 50 rpm. If there is, the liquid pool (pure water paddle) spreads to a desired size, so that the rotation speed of the wafer in the step (S2) of mixing the pure water DIW and the coating liquid TARC is within the range of 10 rpm to 50 rpm. It can be assumed that the same result as in the above evaluation experiment is obtained.

  If the rotation speed of the wafer is lower than 10 rpm, a part of the outer weir forming the liquid pool (pure water paddle) is broken, and the pure water extends in a whisker (branch) shape from the broken part. The circular shape cannot be maintained. Therefore, it is preferable that the number of rotations of the wafer in the step (S2) of mixing the pure water DIW and the coating liquid TARC is in the range of 10 rpm to 50 rpm.

W Semiconductor wafer (substrate to be processed)
40 Coating treatment device 42 Spin chuck (holding means)
43 Chuck drive mechanism (rotation mechanism)
48a 1st nozzle drive part 48b 2nd nozzle drive part 50 Application liquid nozzle 57 Pure water nozzle 60 Controller (control means)
V1, V2, V3 On-off valve DIW Pure water TARC Anti-reflective liquid

Claims (6)

A substrate coating method for forming an antireflection film by applying a water-soluble antireflection liquid to the surface of a substrate on which a resist film has been formed before exposing the pattern to the substrate to be processed,
Holding a substrate to be processed on which a resist film is formed and rotating the substrate at a first rotational speed to supply pure water to the central portion of the substrate to be processed to form a pool of pure water;
Next, a step of supplying an antireflection liquid to a liquid pool of pure water on the center position of the substrate to be processed and mixing it,
Next, while continuing to supply the antireflection liquid, the step of rotating the antireflection liquid at the second rotation number to diffuse the antireflection liquid;
Drying the antireflection liquid diffused over the entire surface of the substrate to be processed at a rotational speed higher than the first rotational speed and lower than the second rotational speed;
A substrate coating method characterized by comprising:   2. The substrate coating method according to claim 1, wherein a time ratio between the mixing step and the diffusing step is shorter than the time of the diffusing step.   2. The substrate coating method according to claim 1, wherein the time ratio between the mixing step and the diffusing step is longer than the time of the diffusing step.   2. The substrate coating method according to claim 1, wherein the time ratio between the mixing step and the diffusing step is the same as the time of the diffusing step and the time of the mixing step.   5. The substrate coating method according to claim 1, wherein the first rotational speed is 10 rpm to 50 rpm.   6. The substrate coating method according to claim 1, wherein the second rotational speed is 2000 rpm to 4000 rpm.

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