JP4484639B2 - Substrate processing method and substrate processing apparatus - Google Patents

Description

  The present invention provides a rinsing process by supplying a rinsing liquid to various substrates (hereinafter simply referred to as “substrates”) such as semiconductor wafers, glass substrates for photomasks, glass substrates for liquid crystal displays, glass substrates for plasma displays, and substrates for optical disks. The present invention relates to a substrate processing method and a substrate processing apparatus.

  The manufacturing process of an electronic component such as a semiconductor device or a liquid crystal display device includes a step of repeatedly forming a fine pattern by repeatedly performing processes such as film formation and etching on the surface of the substrate. Here, in order to perform fine processing satisfactorily, it is necessary to keep the substrate surface clean, and the substrate is subjected to a cleaning process as necessary (see Patent Document 1). In the invention described in Patent Document 1, after cleaning the substrate surface with a processing solution suitable for cleaning processing, that is, a cleaning chemical solution, the processing solution remaining on the substrate surface is rinsed with pure water or carbonated water. Rinse is removed as a liquid. Further, after the rinsing process is completed, the rinse liquid remaining on the substrate surface is shaken off and dried by rotating the substrate at a predetermined rotation speed. In other words, by switching the rotation speed of the substrate in multiple stages, it is possible to avoid high-speed movement of droplets (rinsing liquid including chemical liquid atmosphere) on the substrate surface, and to form streak particles (a kind of water due to chemical liquid precipitation). The occurrence of mark) is suppressed.

JP 2003-92280 A (4 pages, 5 pages)

  However, when pure water or carbonated water is used as the rinse liquid, the following problems occur. In other words, it is known that a watermark is also generated due to the elution of an oxidizable substance (Si in a Si substrate) from the substrate surface to the rinsing liquid during drying. Or carbonated water cannot be used to sufficiently suppress the elution of Si from the rinsing liquid. As a result, Si is eluted into the rinsing liquid and dried during the rinsing process performed immediately before the drying process. A watermark may be generated on the surface of the substrate after the processing, which may cause a serious defect such as a film formation failure. In particular, when the substrate processing is performed to remove the Si oxide film on the Si substrate or the poly-Si substrate with an HF-based cleaning chemical, the substrate surface becomes a hydrophobic surface state due to the exposure of Si. A watermark due to elution of Si was likely to occur. However, no effective countermeasures have been conventionally taken in this regard, leaving much room for improvement.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a substrate processing method and a substrate processing apparatus capable of preventing the generation of a watermark associated with a rinsing process using a rinsing liquid.

The substrate processing method and the substrate processing apparatus according to the present invention are configured as follows in order to achieve the above-described object. The substrate processing method according to the present invention includes a wet processing step of supplying a processing liquid to a substrate to perform a predetermined wet processing, a rinsing liquid generation step of generating a rinsing liquid, and one end of the wet processing step after the wet processing step. by feeding to the nozzle of the rinse liquid along the connected supply path, the rinsing liquid is supplied from a nozzle surrounding atmosphere substrate which is an inert gas atmosphere, a rinsing step for performing rinsing treatment to the substrate by the rinse liquid The rinsing liquid generating step includes a step of mixing dilute hydrochloric acid or dilute hydrofluoric acid with pure water fed from the other end side of the supply path, and dissolving nitrogen in the fluid flowing through the supply path so that the pH becomes 5 or less. It is a process for producing a liquid. Further, the substrate processing apparatus according to the present invention has a supply path by mixing dilute hydrochloric acid or dilute hydrofluoric acid with pure water flowing toward the nozzle along a supply path connected to the nozzle at one end thereof. PH adjusting means for adjusting the pH of the liquid mixture flowing through 5 to 5 or less, nitrogen dissolving means for dissolving nitrogen in the fluid flowing through the supply path, and a gas supply unit in which the ambient atmosphere of the substrate is an inert gas atmosphere , A mixed liquid whose pH is adjusted by the pH adjusting means and dissolved in nitrogen by the nitrogen dissolving means is sent as a rinsing liquid to the nozzle along the supply path, and the rinsing is performed from the nozzle to the substrate which has been made an inert gas atmosphere by the gas supply unit. A liquid is supplied, and the substrate is rinsed with a rinse liquid.

  According to such a configuration, a pure liquid is mixed with dilute hydrochloric acid or dilute hydrofluoric acid to produce a mixed liquid having a pH lowered to 5 or lower and used as a rinsing liquid. That is, the rinse treatment of the substrate is performed by supplying the rinse liquid thus generated to the substrate from the nozzle. Thus, by adjusting the pH of the rinsing solution to be 5 or less, the elution reduction of the oxidizable substance from the substrate is effectively performed, and the generation of watermarks accompanying the rinsing process is prevented. The operational effects will be described in detail later with reference to specific experiments and verification results. In addition, charging of the substrate during the rinsing process can be effectively prevented.

Here, the pH of the rinsing liquid can be adjusted to 5 or less by mixing a carbon dioxide gas (CO ₂ ) used in the prior art and other low pH substances having a pH lower than that of pure water. is there. However, for example, when the pH is adjusted using carbon dioxide gas, the following problems occur. That is, even if carbon dioxide gas is dissolved in pure water to produce a rinse liquid (carbonated water) and the pH of the rinse liquid is lowered, the amount of carbon dioxide dissolved in pure water is maintained while rinsing, That is, it is difficult to perform the rinsing process while the pH of the rinsing liquid is lowered. In particular, when performing single wafer processing, the amount of carbon dioxide dissolved is greatly reduced until the rinse liquid supplied on the substrate spreads over the entire surface of the substrate, and the pH of the rinse liquid increases. . Further, even if the amount of dissolved carbon dioxide is increased in order to lower the pH of the rinsing solution (theoretically, it can be lowered to around pH 4), a large amount of carbon dioxide is consumed and the running cost increases. .

  On the other hand, dilute hydrochloric acid or dilute hydrofluoric acid has a high degree of ionization, and the pH of the rinsing liquid can be easily lowered by adding a small amount to pure water. In addition, unnecessary materials do not remain on the substrate after the rinsing process. On the other hand, with other low pH substances other than dilute hydrochloric acid or dilute hydrofluoric acid, the pH does not drop to the desired value unless it is added in a large amount to pure water, or unwanted substances remain on the substrate after rinsing. End up. For example, when sulfuric acid is used as the low pH substance, sulfides may remain on the substrate and may be detected as particles. In addition, when nitric acid is used as the low pH substance, the substrate surface may be oxidized. As described above, dilute hydrochloric acid or dilute hydrofluoric acid is suitable as the pH adjusting substance for the rinsing liquid. By using a rinsing liquid adjusted to pH using dilute hydrochloric acid or dilute hydrofluoric acid, low running cost and excellent quality are achieved. The rinse process can be executed with.

  When the rinsing process is performed in multiple steps, the pH is adjusted to 5 or less by mixing dilute hydrochloric acid or dilute hydrofluoric acid with pure water at least when performing the final rinsing process immediately before drying the substrate. The rinse process should just be performed with respect to a board | substrate by the rinse liquid formed.

Further, in this invention, the nitrogen dissolved in the fluid flowing through the supply path. According to this, a fluid in which dilute hydrochloric acid or dilute hydrofluoric acid is mixed with pure water and nitrogen is dissolved is generated as the rinse liquid. In the present invention, “fluid flowing in the supply path” means pure water or a mixed liquid (pure water + dilute hydrochloric acid or dilute hydrofluoric acid). That is, nitrogen is dissolved in a mixed solution obtained by mixing dilute hydrochloric acid or dilute hydrofluoric acid into pure water fed from the other end of the supply path, or after dissolving nitrogen in pure water, dilute hydrochloric acid or Diluted hydrofluoric acid is mixed, or dilute hydrochloric acid or dilute hydrofluoric acid and nitrogen are simultaneously dissolved in pure water, and a pH-adjusted nitrogen-rich fluid is generated as a rinse liquid. In this manner, the dissolved oxygen in the rinse liquid is reduced by dissolving the nitrogen in the rinse liquid, and the rinse treatment is performed in an inert gas atmosphere, so that the elution of the oxidizable substance from the substrate is reduced. As a result, by adjusting the pH of the rinsing liquid and dissolving the nitrogen, it is possible to more effectively prevent the generation of watermarks accompanying the rinsing process.

  Further, the position where nitrogen is dissolved is not particularly limited, but for one of the following reasons, one end side (nozzle side) of the supply path with respect to a position where dilute hydrochloric acid or dilute hydrofluoric acid is mixed or a pH adjusting means. It is preferable to dissolve nitrogen in the mixed solution. This is because when this configuration is adopted, nitrogen is dissolved in a mixed solution of pure water and dilute hydrochloric acid or dilute hydrofluoric acid, so that it is dissolved in pure water and dilute hydrochloric acid or dilute hydrofluoric acid before mixing. This is because the oxygen that has been reduced can be reduced, and the above-described effects can be more suitably exhibited.

According to the present invention, pure water is mixed with dilute hydrochloric acid or dilute hydrofluoric acid, the pH is lowered to 5 or less, and the mixed solution in which nitrogen is dissolved is used as the rinsing liquid to rinse the substrate in an inert gas atmosphere. Processing is being executed. For this reason, the elution of the substance to be oxidized into the low-dissolved oxygen rinse liquid is reduced, and the generation of the watermark can be effectively prevented. In addition, charging of the substrate during the rinsing process can be effectively prevented.

<Watermark area relative to pH of rinse solution>
The inventor of the present application investigated the influence of the pH of the rinsing liquid used for the rinsing treatment on the generation of watermarks on the substrate surface. More specifically, a Si (silicon) substrate is selected as a representative example of the substrate, and the pH of the rinsing solution described in “Means for Solving the Problems” is effectively reduced without damaging the substrate. The substrate was rinsed with a rinsing solution adjusted in pH using dilute hydrochloric acid among dilute hydrochloric acid and dilute hydrofluoric acid, and the watermark on the substrate surface after drying was evaluated.

FIG. 1 is a graph showing the relationship of the watermark area to the pH of the rinse solution. Specifically, after etching treatment with hydrofluoric acid, it occurs on the substrate when rinse treatment is performed using rinse solutions having different pH values (here, rinse solutions having pHs of 3, 4, 5, 7, and 9). The watermark was evaluated. As a substrate to be evaluated, a patterned n-type polycrystalline Si substrate having a diameter of 200 mm (phosphorus doping amount: 4 × 10 ²⁰ cm ³ ) is used. As the rinsing liquid, pure water (deionized water; DIW) is used as a neutral (pH 7) rinsing liquid, and ammonia water is used on the alkaline side (pH 9). On the acidic side (pH 3, 4, 5), a rinsing solution whose pH is adjusted by mixing a predetermined amount of diluted hydrochloric acid with pure water so as to obtain a desired pH is used. In addition to the rinsing liquid obtained by mixing dilute hydrochloric acid, pH 5 is evaluated using a rinsing liquid adjusted to pH by mixing carbon dioxide (CO ₂ ) with pure water instead of dilute hydrochloric acid as a comparison target.

  The experimental results in the figure are obtained as follows. First, the substrate prepared for each rinsing solution is treated with hydrofluoric acid. Thereafter, each substrate is rinsed with a rinsing solution having a different pH and dried. A single wafer cleaning device (spin processor MP-2000) manufactured by Dainippon Screen Mfg. Co., Ltd. is used for these substrate processes. And the watermark area | region is measured for the watermark which generate | occur | produces on the board | substrate surface after a drying process using the defect inspection apparatus KLA-2132 made from KLA Tencor.

  As is clear from FIG. 1, when the pH of the rinse liquid is 5 or less, the watermark area is remarkably reduced as compared with pH 7 and 9. In addition, when the pH is adjusted by mixing dilute hydrochloric acid with pure water even when the pH is the same, and when the pH is adjusted by mixing carbon dioxide with pure water (carbonated water), the pH is adjusted by mixing dilute hydrochloric acid with pure water. The case has a smaller watermark area. As described in “Means for Solving the Problems”, even if carbon dioxide gas is mixed with pure water to produce a rinse liquid (carbonated water), the amount of carbon dioxide dissolved in pure water during the rinse treatment It is difficult to perform the rinsing process while maintaining the temperature, and carbon dioxide gas escapes from the rinsing liquid during the rinsing process. In addition, in order to lower the pH using carbon dioxide gas, there is a problem that running cost increases due to consumption of a large amount of carbon dioxide gas. On the other hand, when dilute hydrochloric acid is used, there is no such problem, and the pH of the rinse liquid can be easily adjusted by adding a small amount.

  Next, the effect of dissolving nitrogen in the rinse liquid will be described. Specifically, pure water dissolved in nitrogen (hereinafter referred to as “nitrogen-dissolved water”) and pure water not dissolved in nitrogen (degassed pure water supplied from the utility of the factory, hereinafter referred to as “equipment supply water” )) Is mixed with dilute hydrochloric acid to produce pH-adjusted rinse solutions (pH of 3, 4, and 5). And the effect of nitrogen dissolution is investigated by confirming the watermark generated when the substrate is processed with each generated rinse solution.

  FIG. 2 is a graph showing the relationship between the presence or absence of nitrogen dissolution and the watermark area. As is clear from FIG. 2, the rinse solution dissolved with nitrogen (the rinse solution prepared based on the nitrogen-dissolved water, “with nitrogen dissolution” in the figure) is the rinse solution not dissolved with nitrogen (equipment supplied water). Compared with the rinse solution prepared in the above and “No nitrogen dissolution” in the figure, the water mark area is smaller in any of the cases of pH 3, 4 and 5. In particular, in FIG. 2, the watermark area when treated with a nitrogen-dissolved rinse at pH 3 and 4 is “0” (below the detection limit). From this result, it is understood that elution of Si from the substrate is suppressed by dissolving nitrogen in the rinsing liquid to reduce dissolved oxygen in the rinsing liquid. As described above, the occurrence of the watermark can be more effectively prevented by adjusting the pH of the rinsing liquid and dissolving the nitrogen.

  Accordingly, in view of the above knowledge, the generation of watermarks is prevented by using a rinsing liquid having a pH of 5 or less by mixing dilute hydrochloric acid or dilute hydrofluoric acid with pure water. Moreover, the generation of further watermarks is suppressed by reducing the dissolved oxygen in the rinse solution. Hereinafter, specific embodiments will be described in detail with reference to the drawings.

<First Embodiment>
FIG. 3 is a cross-sectional view showing the overall configuration of the substrate processing apparatus according to the first embodiment of the present invention. FIG. 4 is a block diagram showing a control configuration of the substrate processing apparatus of FIG. As shown in FIG. 3, the substrate processing apparatus 100 performs film removal processing, rinsing processing, and drying processing on the substrate W in the same processing unit main body 101 while the substrate W is held by the spin chuck 1. Execute.

  The spin chuck 1 includes a disk-shaped base member 2 that also functions as a blocking member on the back side of the substrate, and three or more holding members 3 provided on the upper surface thereof. Each of these holding members 3 includes a support portion 3a for placing and supporting the outer peripheral end portion of the substrate W from below, and a regulating portion 3b for regulating the position of the outer peripheral edge of the substrate W. These holding members 3 are provided in the vicinity of the outer peripheral end of the base member 2. In addition, each regulating portion 3b can take an operation state in which the substrate W is held in contact with the outer peripheral edge of the substrate W and a non-operation state in which the holding of the substrate W is released away from the outer peripheral edge of the substrate W. After the substrate W is loaded / unloaded to / from the support portion 3a by a transfer robot (not shown) in a non-acting state, the substrate W is placed on the support portion 3a with the surface facing up. The substrate W is held by the spin chuck 1 by switching each restricting portion 3b to the operating state. The operation of the holding member 3 (the restricting portion 3b) can be realized by, for example, a link mechanism disclosed in Japanese Patent Laid-Open No. 63-1553839.

  An upper end portion of the rotating shaft 4 is attached to the lower surface of the base member 2. A pulley 5a is fixed to the lower end portion of the rotating shaft 4, and a rotational driving force of the motor 5 is interposed between the pulley 5a and a pulley 5b fixed to the rotating shaft of the motor 5 via a belt 5c. It is configured to be transmitted to the rotating shaft 4. Therefore, the substrate W held on the spin chuck 1 is rotated around the center of the substrate W by driving the motor 5.

  A nozzle 6 is provided at the center of the base member 2. The nozzle 6 is connected to a liquid supply section 50 for supplying a processing liquid and a rinsing liquid to the back surface of the substrate via a pipe 7 inscribed along the central axis of the hollow rotating shaft 4 and the pipe 8. The configuration and operation of the liquid supply unit 50 will be described later.

  In addition, an opening 16 is provided in the center of the base member 2 coaxially with the nozzle 6. The opening 16 is connected to a gas supply unit 20 through a hollow part 17 provided in the rotary shaft 4 coaxially with the pipe 7 and a pipe 19 having an opening / closing valve 18 interposed therebetween. Therefore, by opening the on-off valve 18, an inert gas (for example, nitrogen gas) can be supplied between the base member 2 and the back surface of the substrate W, and the space can be purged with an inert gas atmosphere. It is configured.

  A blocking member 21 is provided above the spin chuck 1. The blocking member 21 is attached to the lower end portion of the suspension arm 22 disposed in the vertical direction. In addition, a motor 23 is provided at the upper end of the suspension arm 22, and by driving the motor 23, the blocking member 21 is rotated about the suspension arm 22. The rotation axis 4 of the rotation axis 4 of the spin chuck 1 and the rotation axis of the suspension arm 22 coincide with each other and are held by the base member 2 and the blocking member 21 as the atmosphere blocking means and the spin chuck 1. The substrate W is rotated about the same axis. The motor 23 is configured to rotate the blocking member 21 in the same direction as the spin chuck 1 (the substrate W held by the spin chuck 1) and at substantially the same rotational speed.

  A nozzle 25 is provided at the center of the blocking member 21. The nozzle 25 is connected to a liquid supply unit 70 for supplying a processing liquid and a rinsing liquid to the substrate surface via a pipe 26 provided along the central axis of the hollow suspension arm 22 and a pipe 27. The configuration and operation of the liquid supply unit 70 will be described in detail later.

  In addition, an opening 35 is provided at the center of the blocking member 21 coaxially with the nozzle 25. The opening 35 is connected to a gas supply unit 39 through a hollow portion 36 provided in the suspension arm 22 coaxially with the tube 26 and a tube 38 having an opening / closing valve 37 interposed therebetween. Then, in the state where the blocking member 21 is disposed close to the surface of the substrate W held by the spin chuck 1, the on-off valve 37 is opened, so that an inert gas is interposed between the blocking member 21 and the surface of the substrate W. (For example, nitrogen gas) is supplied, and the space can be purged with an inert gas atmosphere.

  A cup 40 is disposed around the spin chuck 1 to prevent the processing liquid from scattering around the spin chuck 1. The processing liquid collected in the cup 40 is drained out of the apparatus and is not shown in the figure, but is stored in a tank provided below the cup 40.

  Next, the configuration of the liquid supply units 50 and 70 will be described. Since the liquid supply units 50 and 70 have the same configuration, the configuration of one liquid supply unit 50 will be described here, and the configuration of the other liquid supply unit 70 will be denoted by a corresponding reference numeral. Description is omitted. The liquid supply unit 50 is disposed in the processing unit main body 101, and includes a hydrofluoric acid supply source 51 that supplies hydrofluoric acid and a hydrochloric acid supply source 52a that supplies hydrochloric acid (dilute hydrochloric acid). The hydrofluoric acid supply source 51 is connected to the mixing unit 55 through a pipe 54 having an on-off valve 53 interposed therebetween, while pure water is supplied through a pipe 57 and a pipe 201 having a mixing unit 52b and an on-off valve 56 therebetween. The water supply unit 200 is connected to the mixing unit 55. The pure water supply unit 200 is provided separately from the processing unit main body 101. The mixing unit 52b is connected to a hydrochloric acid supply source 52a via a pipe 52d having an open / close valve 52c, and can mix hydrochloric acid with pure water supplied from the pure water supply unit 200. Yes. Then, the pH of the mixed solution (pure water + hydrochloric acid) is adjusted to a desired value by controlling the flow rate of hydrochloric acid to be mixed. Further, the mixing unit 55 is connected to the nozzle 6 via the pipes 7 and 8, and the mixed liquid adjusted in pH from the nozzle 6 can be discharged toward the substrate W as a rinse liquid. As described above, in this embodiment, the pH adjustment unit 52 including the hydrochloric acid supply source 52a, the mixing unit 52b, the on-off valve 52c, and the pipe 52d on the back surface side of the substrate W functions as the “pH adjustment unit” of the present invention. ing. On the surface side of the substrate W, a pH adjusting unit 72 constituted by a hydrochloric acid supply source 72a, a mixing unit 72b, an on-off valve 72c and a pipe 72d functions as the “pH adjusting means” of the present invention.

  Then, a hydrofluoric acid solution or pure water is selectively directed from the mixing unit 55 to the pipe 8 toward the surface of the substrate W by switching the opening / closing valves 53 and 56 according to a control command from the control unit 80 for controlling the entire apparatus. Can be supplied. That is, when all the on-off valves 53 and 56 are opened, hydrofluoric acid and pure water are supplied to the mixing unit 55 to prepare a hydrofluoric acid aqueous solution having a predetermined concentration. Then, this hydrofluoric acid aqueous solution is discharged from the nozzle 6 toward the back surface of the substrate W through the tubes 7 and 8, and the film adhering to the back surface of the substrate is removed by etching. Further, when the on-off valve 53 is closed and the on-off valve 56 is opened, and the on-off valve 52c is opened, a mixed liquid whose pH is adjusted by mixing dilute hydrochloric acid with pure water is passed through the pipes 7 and 8 as a rinse liquid. Then, it is supplied from the nozzle 6 to the back surface of the substrate W to perform the rinsing process. Here, the pH of the rinsing liquid is adjusted by controlling the flow rate of hydrochloric acid according to the object to be treated. However, the pH of the rinsing liquid is 5 or less from the viewpoint of preventing the generation of watermarks associated with the rinsing process. Adjusted to

  Thus, with respect to the back surface side of the substrate W, the nozzle 6 from the pure water supply unit 200 outside the processing unit main body 101 along the supply path (201-57-8-7) whose one end is connected to the nozzle 6. The pH of the mixed solution is adjusted by mixing hydrochloric acid with pure water flowing toward the surface by the pH adjusting unit 52. Then, the pH-adjusted mixed liquid is supplied as a rinse liquid from the nozzle 6 to the back surface of the substrate W to perform a rinsing process. Similarly, with respect to the surface side of the substrate W, the nozzle 25 is supplied from the pure water supply unit 200 outside the processing unit main body 101 along a supply path (201-77-27-26) whose one end is connected to the nozzle 25. The pH of the mixed solution is adjusted by mixing hydrochloric acid with pure water flowing toward the surface by the pH adjusting unit 72. Then, the pH-adjusted mixed liquid is supplied as a rinse liquid from the nozzle 25 to the surface of the substrate W to be rinsed.

  Next, the operation of the substrate processing apparatus configured as described above will be described with reference to FIG. FIG. 5 is a flowchart showing the operation of the substrate processing apparatus of FIG. In this substrate processing apparatus 100, after the unprocessed substrate W is transferred to the spin chuck 1 by the transfer robot and held by the holding member 3 (step S1), each part of the apparatus is as follows in the control unit 80 that controls the entire apparatus. The film removal process, the rinse process, and the drying process are performed in this order.

  In step S2, after the blocking member 21 is disposed close to the surface of the substrate W held by the spin chuck 1, the driving of the motor 5 is started with the substrate W sandwiched between the base member 2 and the blocking member 21. Then, the substrate W is rotated together with the spin chuck 1. In addition, all the on-off valves 53, 73, 56, and 76 are opened to supply hydrofluoric acid and pure water to the mixing units 55 and 75 to prepare a hydrofluoric acid aqueous solution having a predetermined concentration. To pump. Thereby, supply of the hydrofluoric acid aqueous solution from the nozzles 6 and 25 to both surfaces of the substrate W is started (step S3). Thereby, the etching removal of the film adhering to both surfaces of the substrate W is started. Thus, in this embodiment, the film removal step corresponds to the “wet treatment step” of the present invention.

  When it is confirmed in step S4 that the film removal process is completed, all the on-off valves 53, 73, 56, and 76 are closed, and the supply of the hydrofluoric acid aqueous solution from the nozzles 6 and 25 to the substrate W is stopped. Is rotated at a high speed, and the hydrofluoric acid aqueous solution is shaken off to drain out of the apparatus.

  When the draining of the hydrofluoric acid aqueous solution is thus completed (step S5), the on-off valves 18 and 37 are opened, and an inert gas is supplied to the space between the substrate W and the base member 2 and the blocking member 21. After the atmosphere around the substrate W is changed to an inert gas atmosphere, when the on-off valves 56 and 76 are opened and the on-off valves 52c and 72c are opened, a predetermined amount of hydrochloric acid is mixed with pure water so that the pH is 5 or less. The mixed liquid adjusted to the value is generated as the rinse liquid (corresponding to the “rinse liquid generation step” of the present invention). Then, this rinsing liquid is supplied to both main surfaces of the substrate W, and a rinsing process (corresponding to the “rinsing step” of the present invention) is performed on the substrate W (step S6). After completion of the rinsing process, the on-off valves 56, 76, 52c, and 72c are closed, and the substrate W is continuously rotated until the substrate W is dried to perform the drying process (step S7). After the drying of the substrate W is completed, the rotation of the substrate is stopped and the on-off valves 18 and 37 are closed to stop the supply of the inert gas.

  As described above, the oxygen atmosphere around the substrate W that can be dissolved in the rinsing liquid can be reduced by making the atmosphere around the substrate W an inert gas atmosphere during the rinsing process and the drying process. it can. Thereby, it is possible to suppress an increase in dissolved oxygen in the rinsing liquid during a period (for example, about 30 seconds) from when the rinsing liquid is discharged from the nozzles 6 and 25 toward the substrate W until the rinsing liquid is removed from the substrate W.

  Thus, when a series of substrate processing (film removal processing, rinsing processing and drying processing) is completed, the blocking member 21 is separated from the surface of the substrate W held by the spin chuck 1 and the substrate holding by the holding member 3 is released. Thereafter, the transfer robot carries the processed substrate W to the next substrate processing apparatus (step S8).

  As described above, according to this embodiment, since the substrate W is rinsed using the mixed liquid in which diluted hydrochloric acid is mixed with pure water and the pH is lowered to 5 or less as the rinse liquid, The elution of Si is reduced, and the generation of watermarks can be prevented. As a result, it is possible to prevent film formation problems such as an increase in contact resistance and pattern defects. In addition, charging of the substrate W during the rinsing process can be effectively prevented.

  In particular, according to this embodiment, since dilute hydrochloric acid is used as the pH adjusting substance of the rinsing liquid, the following effects can be obtained. That is, since dilute hydrochloric acid has a high degree of ionization, the pH of the rinsing liquid can be lowered by adding a very small amount, and the pH of the rinsing liquid can be easily adjusted and the running cost can be reduced. In addition to the trace amount of dilute hydrochloric acid in the rinsing liquid, unnecessary substances do not remain on the substrate W after the processing, so that the rinsing processing can be performed with high quality.

<Second Embodiment>
FIG. 6 is a diagram showing the configuration of the substrate processing apparatus according to the second embodiment of the present invention. The second embodiment is largely different from the first embodiment in that the first embodiment uses a mixed liquid obtained by mixing hydrochloric acid (dilute hydrochloric acid) with pure water to adjust the pH as a rinsing liquid. In the second embodiment, nitrogen is further dissolved in a mixed solution (pure water + hydrochloric acid), whereby a pH-adjusted nitrogen-rich fluid is used as a rinse solution. That is, in the second embodiment, the nitrogen dissolving units 58 and 78 are disposed between the mixing units 55 and 75 and the mixing units 52b and 72b, respectively, and the pH flowing toward the mixing units 55 and 75 is adjusted. Nitrogen is dissolved in the liquid mixture, and the nitrogen-dissolved fluid is supplied as a rinse liquid from the nozzles 6 and 25 to the substrate W.

  The nitrogen dissolving units 58 and 78 are, for example, a bubbling device using a tank or an existing device using a hollow fiber, and are connected to a nitrogen gas supply source (not shown). Therefore, the nitrogen-rich fluid is obtained by dissolving the nitrogen gas from the nitrogen gas supply source in the fluid flowing through the supply path, that is, the pure water from the pure water supply unit 200 or the mixed liquid obtained by mixing diluted hydrochloric acid with the pure water. It can be generated. Therefore, in this embodiment, the pH adjusted to 5 or less and the nitrogen-dissolved fluid can be supplied as the rinse liquid to the substrate W, and the rinse treatment is performed on the substrate W by the rinse liquid.

  Also in the substrate processing apparatus 100 configured as described above, a series of substrate processing (film removal processing, rinsing processing, and drying processing) is performed by the operation procedure shown in FIG. An effect is obtained. That is, the elution of Si from the substrate W is reduced, and the generation of watermarks associated with the rinsing process is prevented. Furthermore, in this embodiment, the dissolved oxygen in the rinse liquid is reduced by dissolving the rinse liquid with nitrogen, and the elution of Si from the substrate W is reduced. As a result, the occurrence of watermarks can be more effectively prevented by adjusting the pH of the rinse liquid and dissolving the nitrogen.

  Further, according to this embodiment, since the nitrogen dissolving units 58 and 78 are provided in the processing unit main body 101, the flow path from the generation of the rinse liquid to the discharge from the nozzles 6 and 25 is shortened. Can do. For this reason, the generated rinsing liquid is quickly supplied to the substrate W, and the rinsing process can be performed by supplying the rinsing liquid to the substrate W within a time period in which the effect of dissolving nitrogen is maintained. That is, it is possible to suppress an increase in dissolved oxygen in the rinse liquid during a period from when the rinse liquid is discharged from the nozzles 6 and 25 toward the substrate W until the rinse liquid is removed from the substrate W. As a result, elution of Si from the substrate W is suppressed, and the generation of watermarks is effectively prevented.

  Further, according to this embodiment, nitrogen is dissolved in a mixed solution obtained by mixing dilute hydrochloric acid with pure water on one end side (nozzles 6 and 25 side) of the supply path with respect to the pH adjustment units 52 and 72. The following effects can be obtained. That is, oxygen dissolved in pure water and dilute hydrochloric acid before mixing can be reduced by dissolving nitrogen in the mixed solution of pure water and dilute hydrochloric acid, and the above-described effects can be more suitably exhibited. Can do.

<Third Embodiment>
FIG. 7 is a diagram showing a third embodiment of the substrate processing apparatus according to the present invention. The third embodiment differs greatly from the first embodiment in that the first embodiment mixes hydrochloric acid (dilute hydrochloric acid) directly with pure water flowing through the tubes 57 and 77 through the mixing units 52b and 72b. In contrast, in the third embodiment, the rinsing liquid is generated by mixing hydrochloric acid with pure water in a storage tank 41 described later. With this configuration, the following advantages can be obtained. That is, in the first embodiment, since hydrochloric acid is mixed with pure water in-line, it is difficult to control the flow rate of hydrochloric acid, and it is difficult to finely adjust the pH of the rinse liquid. This is because it is necessary to control a small amount of hydrochloric acid in order to adjust the pH of the rinse liquid to a desired value. On the other hand, in this embodiment, after adjusting the pH of the liquid mixture by mixing hydrochloric acid with pure water, the pH of the rinse liquid is finely adjusted because part (or all) of the pH-adjusted liquid mixture is taken out. Easy to do.

  As shown in FIG. 7, pure water from the pure water supply unit 200 provided outside the processing unit main body 101 is supplied to the cabinet unit 400. The cabinet unit 400 is frequently used to generate a treatment liquid by combining a plurality of types of chemicals and pure water. In this embodiment, the cabinet part 400 generates a rinse liquid obtained by mixing pure water and hydrochloric acid. It is used for. The cabinet unit 400 includes a storage tank 41 that stores a mixed solution of pure water and hydrochloric acid, and one end of a pipe 201 for supplying pure water into the storage tank 41 is taken into the storage tank 41. The other end is connected to the pure water supply unit 200 through the open / close valve 202. In addition, one end of a pipe 62a for supplying hydrochloric acid into the storage tank 41 is taken into the storage tank 41, and the other end is connected to a hydrochloric acid supply source 62 through an on-off valve 62b.

  Further, the other end of the supply pipe 42 whose one end is connected to the pipes 57 and 77 is inserted into the storage tank 41 so that the mixed liquid stored in the storage tank 41 can be supplied toward the nozzles 6 and 25. It is configured. That is, the supply pipe 42 is connected to the branch pipes 57 and 77 having the on-off valves 56 and 76 through the on-off valve 43 and communicated with the nozzles 6 and 25. The supply pipe 42 includes a metering pump 44 that sends the mixed liquid stored in the storage tank 41 to the supply pipe 42, a temperature controller 45 that adjusts the temperature of the liquid mixture sent to the supply pipe 42 by the metering pump 44, A filter 46 that removes impurities and the like in the mixed solution is provided.

A circulation pipe 47 branched from the supply pipe 42 is provided between the on-off valve 43 of the supply pipe 42 and the filter 46. For this reason, the mixed liquid sent out by the metering pump 44 through the circulation pipe 47 is passed through the temperature controller 45 and the filter 46 and returned to the storage tank 41, so that the mixed liquid can be circulated. Yes. An open / close valve 48 is interposed in the circulation pipe 47, and the mixed liquid can be circulated by opening the open / close valve 48 and closing the open / close valve 43. On the other hand, the liquid mixture can be supplied toward the nozzles 6 and 25 by opening the on-off valve 43 and closing the on-off valve 48.

  In the substrate processing apparatus 100 configured as described above, pure water from the pure water supply unit 200 and hydrochloric acid from the hydrochloric acid supply unit 62 are mixed in the storage tank 41 to adjust to a predetermined pH of 5 or less. A mixed liquid is produced. Then, by opening the on-off valve 48 with the on-off valve 43 closed, the pH of the mixed solution can be adjusted and circulated while removing impurities and the like in the mixed solution. Here, the on-off valve 43 is opened and the on-off valve 48 is closed, so that the mixed liquid whose pH is adjusted is fed into the branch pipes 57 and 77. Furthermore, by opening the on-off valves 56 and 76, the mixed liquid whose pH is adjusted to 5 or less is supplied from the nozzles 6 and 25 to the two main surfaces of the substrate W as a rinsing liquid, and the rinsing process is performed on the substrate W. Done.

  Thus, in this embodiment, about the back surface side of the board | substrate W, the process unit main body is along the supply path | route (201-storage tank 41-42-57-8-7) where the one end was connected to the nozzle 6. The pH of the mixed liquid (pure water + hydrochloric acid) is adjusted by mixing hydrochloric acid in the storage tank 41 with the pure water flowing from the pure water supply unit 200 outside the nozzle 101 toward the nozzle 6. Then, the pH-adjusted mixed liquid is supplied as a rinse liquid from the nozzle 6 to the back surface of the substrate W to perform a rinsing process. Similarly, with respect to the surface side of the substrate W, the mixed liquid is stored in the storage tank 41 along a supply path (201-storage tank 41-42-77-27-26) whose one end is connected to the nozzle 25. While adjusting the pH, the liquid mixture is supplied as a rinse liquid from the nozzle 25 to the surface of the substrate W to be rinsed.

  As described above, also in this embodiment, since the mixed liquid in which diluted hydrochloric acid is mixed with pure water and the pH is lowered to 5 or less is used as the rinsing liquid, the same effects as those in the first embodiment can be obtained. That is, the generation of watermarks can be prevented by the action of reducing the elution of Si from the substrate W. Furthermore, in this embodiment, since the liquid mixture is once stored in the storage tank 41 and the pH of the rinse liquid is adjusted, the pH of the rinse liquid can be easily finely adjusted.

<Fourth embodiment>
FIG. 8 is a diagram showing a fourth embodiment of the substrate processing apparatus according to the present invention. The fourth embodiment differs greatly from the first embodiment in that the first embodiment is a so-called single-wafer type that processes the substrates W one by one, whereas the fourth embodiment has a plurality of This is a so-called batch type in which the substrates W are collectively processed. In this batch-type substrate processing apparatus, for example, an etching solution (hydrofluoric acid aqueous solution or the like) is used to perform a series of various processing (film removal processing, rinsing processing, drying processing using a processing solution) on a plurality of substrates W. The film removal processing tank for storing the processing liquid, etc., the film removal processing tank for performing the film removal processing on the substrate W, the rinsing processing tank for storing the pure water as the rinsing liquid, and rinsing the substrate W, and the substrate W by spin drying or the like A drying treatment tank for drying is provided. FIG. 8 shows the substrate processing apparatus for the rinsing process.

  The rinsing treatment tank 91 shown in FIG. 8 performs a rinsing process for washing away the treatment liquid adhering to the surface of the substrate W and the particles generated thereby after the film removal process is performed in the film removal treatment tank. Specifically, the plurality of substrates W processed in the film removal processing tank are transferred to the lifter device 92 that can be held by the three arms 92a, and the lifter device 92 is lowered in the rinsing processing tank 91. Is immersed in a rinse solution. The rinsing liquid in the rinsing tank 91 is supplied from the bottom of the tank before the rinsing liquid supply pipe 93, and further through the branch pipes 93a and 93b. Each of the supply parts 94a and 94b is injected toward the center side. A plurality of nozzles (not shown) for discharging the rinsing liquid between the substrates W from the left and right lower sides of the plurality of substrates W immersed in the rinsing treatment tank 91 are provided in the pair of rinsing liquid supply units 94a and 94b. The rinsing liquid discharged from each nozzle between the nozzles rises while the rinsing liquid ejected from both the left and right sides forms an upward flow at the center of the tank, and the upper part of the tank. Overflow from the opening. Contaminants such as particles generated by the processing liquid due to the overflow are received in the overflow tanks 95a and 95b together with the processing liquid and the rinsing liquid, and discharged out of the tank.

  Next, the configuration of the liquid supply unit 50 will be described. The configuration of the liquid supply unit 50 is basically the same as that of the first embodiment except that there is no hydrofluoric acid supply system that supplies hydrofluoric acid as a processing liquid (these are provided in the film removal processing tank). is there. That is, the pure water supply unit 200 outside the processing unit main body 101 is connected to the pipe 201, the pipe 93 provided with the on-off valve 56 and the mixing unit 52b, and the rinsing liquid supply unit 94a, via the branch pipes 93a and 93b. 94b. The mixing unit 52b is connected to a hydrochloric acid supply source 52a through a pipe 52d having an open / close valve 52c, and can mix hydrochloric acid (dilute hydrochloric acid) with pure water supplied from the pure water supply unit 200. It has become. For this reason, by adjusting the on-off valve 52c, it is possible to adjust the pH of the mixed liquid by mixing hydrochloric acid with pure water. Then, by opening the on-off valve 52c and opening the on-off valve 56, the mixed liquid whose pH is lowered to 5 or less is supplied as a rinsing liquid to each substrate W immersed in the rinsing treatment tank 91.

  Thus, in this embodiment, pure water is supplied along the supply path (201-93-93a or 201-93-93b) whose one end is connected to the nozzles disposed in the rinsing liquid supply units 94a and 94b. The pH of the mixed solution is adjusted by mixing hydrochloric acid with pure water flowing from the supply unit 200 toward the nozzle by the pH adjusting unit 52. Then, the pH-adjusted mixed solution is supplied as a rinsing liquid from the nozzles to each substrate W to be rinsed.

  The rinse treatment tank 91 is accommodated in a sealed structure 96, and a gas supply unit 20 is connected to the sealed structure 96 through a pipe 19 having an on-off valve 18 interposed therebetween. For this reason, by opening the on-off valve 18, an inert gas (such as nitrogen) is supplied into the sealed structure 96 to fill the vicinity of the rinsing treatment tank 91 with the inert gas, and from an exhaust port (not shown). It is configured to be purged.

  As described above, in this embodiment, since the mixed liquid in which diluted hydrochloric acid is mixed with pure water and the pH is lowered to 5 or less is supplied as the rinse liquid to the plurality of substrates W immersed in the rinse treatment tank 91, The same effect as the first embodiment can be obtained. That is, the elution of Si from each substrate W can be reduced and the generation of watermarks can be prevented.

  Further, since the vicinity of the periphery of the rinsing treatment tank 91 is an inert gas atmosphere, the amount of oxygen dissolved in the rinsing liquid is reduced, and the rise of dissolved oxygen in the rinsing liquid is suppressed, and the rinsing treatment tank 91 for the substrate W is also performed. Oxidation of the substrate W accompanying loading / unloading to / from the substrate can be prevented. For this reason, elution of Si from each substrate W can be suppressed and the generation of watermarks can be more effectively prevented.

<Others>
The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, a series of processing is performed on both surfaces of the substrate W, but the present invention can be applied to a substrate processing apparatus that performs substrate processing only on one surface. For example, in the case where only one surface of the substrate W has a problem with the occurrence of the watermark, it is advantageous in terms of cost if the substrate processing is performed only on the one surface.

  In the above embodiment, the pH of the rinsing solution is adjusted by adding hydrochloric acid (dilute hydrochloric acid) as the pH adjusting substance. However, hydrofluoric acid is used from the viewpoint that there is no problem with the degree of ionization and the residue. Even when (dilute hydrofluoric acid) is added, the same effect can be obtained. When the pH of the rinsing liquid is adjusted by mixing hydrofluoric acid with pure water, for example, in the first and second embodiments, the hydrofluoric acid from the hydrofluoric acid supply sources 51 and 71 without providing the pH adjusting units 52 and 72. Can be used. In this case, a predetermined amount of hydrofluoric acid is added to pure water by opening the on-off valves 56 and 76 and adjusting the on-off valves 53 and 73 during the rinsing process. As a result, the pH of the rinsing liquid can be lowered to a desired value of 5 or less, and the generation of watermarks associated with the rinsing process can be prevented.

  In the above embodiment, the rinsing process is performed after the film removal process using hydrofluoric acid and the pH is adjusted before the drying process. However, when the rinsing process is performed in multiple steps, When performing at least the final rinsing step immediately before drying the substrate W, the substrate W is rinsed with a rinsing liquid in which diluted hydrochloric acid or diluted hydrofluoric acid is mixed with pure water to adjust the pH to 5 or less. It only has to be executed.

  In the second embodiment, the nitrogen dissolving units 58 and 78 are provided in the processing unit main body 101, but the nitrogen dissolving units 58 and 78 may be provided outside the processing unit main body 101. Specifically, the nitrogen dissolving units 58 and 78 may be inserted into a utility line (tube 201) in a factory where the pure water supply unit 200 and the processing unit main body 101 communicate with each other. By providing the nitrogen dissolving units 58 and 78 outside the processing unit main body 101 in this way, the processing unit main body 101 can be made compact, and the rise of dissolved oxygen in pure water reaching the processing unit main body 101 can be increased. Can be suppressed.

  Further, in the second embodiment, nitrogen is dissolved in a mixed solution obtained by mixing dilute hydrochloric acid with pure water. However, the present invention is not limited to this, and after dissolving nitrogen in pure water, dilute hydrochloric acid is added to the nitrogen-rich pure water. (Or dilute hydrofluoric acid) is mixed, or dilute hydrochloric acid (or dilute hydrofluoric acid) and nitrogen are simultaneously dissolved in pure water to generate a pH-adjusted nitrogen-rich fluid as a rinsing liquid. Good.

  Also in the third and fourth embodiments, the substrate W may be rinsed by using a nitrogen dissolving unit to dissolve the nitrogen and adjusting the pH adjusted liquid mixture as a rinsing liquid. In this case, after dissolving nitrogen in a mixed solution obtained by mixing dilute hydrochloric acid or dilute hydrofluoric acid with pure water fed from the other end side (pure water supply unit 200 side) of the supply path, or after dissolving nitrogen in pure water Dilute hydrochloric acid or dilute hydrofluoric acid may be mixed with the nitrogen-rich pure water, or dilute hydrochloric acid or dilute hydrofluoric acid and nitrogen may be dissolved simultaneously in the pure water. For example, in the third embodiment, if a nitrogen dissolving unit is provided downstream of the on-off valve 43 and inserted in the supply pipe 42, the pH is adjusted to 5 or less and the nitrogen-dissolved rinsing is performed. The liquid can be sent to the substrate W. As a result, the occurrence of watermarks can be more effectively prevented by adjusting the pH of the rinse liquid and dissolving the nitrogen.

  In the third embodiment, when nitrogen is supplied into the sealed storage tank 41 to purge the space in which the liquid mixture in the storage tank 41 is not stored with nitrogen, Nitrogen can be dissolved in the mixed solution. As a result, it is possible to obtain the same effect as when the nitrogen solution is dissolved in the pH-adjusted mixed solution by the nitrogen dissolving unit.

  In the above embodiment, a hydrofluoric acid aqueous solution is supplied as a processing liquid to the substrate W to perform wet processing on the substrate. However, other processing liquids (for example, a cleaning liquid and a developer) are supplied to the substrate to obtain a predetermined process. The present invention can be applied to a substrate processing apparatus that performs wet processing (for example, cleaning processing and development processing). In short, the present invention can be applied to all substrate processing apparatuses that perform a rinsing process by supplying a rinsing liquid to a substrate.

  The present invention is applied to a substrate processing apparatus that supplies a processing liquid to a substrate and performs a predetermined wet process, and then supplies a rinsing liquid to the substrate to perform a rinsing process on the substrate.

It is a graph which shows the relationship of the watermark area with respect to pH of a rinse liquid. It is a graph which shows the relationship between the presence or absence of nitrogen dissolution and a watermark area. It is sectional drawing which shows the structure of the whole substrate processing apparatus concerning 1st Embodiment of this invention. It is a block diagram which shows the control structure of the substrate processing apparatus of FIG. It is a flowchart which shows operation | movement of the substrate processing apparatus of FIG. It is a figure which shows the structure of the substrate processing apparatus concerning 2nd Embodiment of this invention. It is a figure which shows the structure of the substrate processing apparatus concerning 3rd Embodiment of this invention. It is a figure which shows the structure of the substrate processing apparatus concerning 4th Embodiment of this invention.

Explanation of symbols

6, 25 ... Nozzle 52, 72 ... pH adjustment unit (pH adjustment means)
58, 78 ... Nitrogen dissolving unit (nitrogen dissolving means)
DESCRIPTION OF SYMBOLS 100 ... Substrate processing apparatus 400 ... Cabinet part (pH adjustment means)
W ... Board

Claims (5)

A wet processing step of supplying a processing liquid to the substrate and applying a predetermined wet processing;
A rinsing liquid generating step for generating a rinsing liquid;
After the wet processing step, the rinsing liquid is sent to the nozzle along a supply path having one end connected to the nozzle, and the rinsing liquid is supplied from the nozzle to the substrate in which the surrounding atmosphere is an inert gas atmosphere. And a rinsing step of rinsing the substrate with the rinsing liquid,
In the rinsing liquid generating step, dilute hydrochloric acid or dilute hydrofluoric acid is mixed with pure water fed from the other end side of the supply path, and nitrogen is dissolved in the fluid flowing through the supply path so that the pH becomes 5 or less. A substrate processing method, which is a step of generating a rinse liquid.   The substrate processing method according to claim 1, wherein the rinsing step is a final rinsing step performed immediately before drying the substrate. In the rinsing step, a blocking member is disposed to face the substrate, the inert gas is supplied to a space between the substrate and the blocking member, and the rinsing liquid is supplied to the substrate in the space. The substrate processing method according to claim 2 , wherein the supply of the inert gas is continued until the drying of the substrate is completed . A nozzle,
The pH of the liquid mixture flowing through the supply path is adjusted to 5 or less by mixing dilute hydrochloric acid or dilute hydrofluoric acid with pure water flowing toward the nozzle along the supply path connected to the nozzle at one end thereof. and pH adjusting means for,
Nitrogen dissolving means for dissolving nitrogen in the fluid flowing through the supply path;
A gas supply unit that makes the atmosphere around the substrate an inert gas atmosphere ,
The mixed liquid that has been pH-adjusted by the pH-adjusting means and dissolved in nitrogen by the nitrogen-dissolving means is sent as a rinsing liquid to the nozzle along the supply path, and the substrate is made an inert gas atmosphere by the gas supply unit. A substrate processing apparatus, wherein the rinse liquid is supplied from the nozzle and the substrate is rinsed with the rinse liquid. A blocking member disposed in proximity to the substrate;
The substrate processing apparatus according to claim 4 , wherein the nozzle supplies the rinse liquid to the substrate in a space between the substrate supplied with the inert gas from the gas supply unit and the blocking member .

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