Spin processing apparatus and spin processing method

Abstract

To provide a spin treatment apparatus and a spin treatment method for preventing a treatment liquid of spin treatment and an ambient atmosphere from going around to the rear side of an outer peripheral part of a substrate when the spin treatment is performed by dropping the treatment liquid on the rotating substrate.SOLUTION: A rotary adsorption table including a rotary shaft, a rotary placement part that is rotated by the rotary shaft in a state where a substrate is placed thereon, a rotor part that supports a lower part of the rotary placement part and rotates by the rotary shaft, and a gap formed between an outer peripheral part of the rotary placement part and an outer peripheral part of the rotor part; A non-rotating purge box communicating with the gap, a labyrinth portion provided on an outer edge of the non-rotating purge box positioned below the rotor portion, and a side blow portion supplying gas to the purge box and blowing the gas to the gap.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a spin processing apparatus and a spin processing method for dropping a processing liquid used in a semiconductor manufacturing process onto a rotating substrate to perform spin processing. [Background technology]

[0002] In semiconductor manufacturing processes, various semiconductor wafer surface treatments are performed according to each process, including etching to remove damaged layers after backgrinding, application of a developer to the wafer, development of wafers with exposed circuit patterns and then coated with developer, and wafer surface cleaning.

[0003] As a spin processing apparatus for performing such various wafer surface processing, the apparatus described in Patent Document 1 is known.

[0004] In the process of manufacturing IGBTs (Insulated Gate Bipolar Transistors) for power semiconductors, for example, the back surface of a substrate such as a silicon wafer is ground by back grinding (BG), and then the back surface is etched to remove damage caused by grinding.

[0005] If the substrate is a silicon wafer, Si etching is performed. Etching of the back surface of the silicon wafer is performed by adsorbing the patterned surface of the silicon wafer to hold the silicon wafer, rotating the silicon wafer in a spin processing device, and dripping a chemical solution, for example, about 5 to 20 μm of mixed acid, onto the back surface of the silicon wafer from a discharge nozzle installed above the silicon wafer, thereby performing the specified etching.

[0006] When applying a chemical solution to the backside of a substrate, the chemical solution and the surrounding atmosphere tend to find their way around to the outer periphery of the substrate. This creates droplets of 1 mm or less in diameter that adhere to the backside (opposite side) of the etched surface at the outer periphery of the substrate, around 10 mm from the outer periphery. These droplets could potentially increase the defect rate of devices around the substrate. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2001-267278 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the problems of the above-mentioned conventional technology, and aims to provide a spin processing apparatus and a spin processing method that, when a processing liquid is dropped onto a rotating substrate to perform spin processing, prevents the processing liquid and the surrounding atmosphere from flowing around to the back side of the outer periphery of the substrate. [Means for solving the problem]

[0009] In order to solve the above problems, the spin processing apparatus of the present invention is a spin processing apparatus for dropping a processing liquid used in a semiconductor manufacturing process onto a rotating substrate to perform a spin processing, and includes a rotary suction table having a rotating shaft, a rotary mounting section that is rotated by the rotating shaft with a substrate placed on it, a rotor section that supports the lower part of the rotary mounting section and rotates by the rotating shaft, and a gap formed between the outer periphery of the rotary mounting section and the outer periphery of the rotor section, a non-rotating purge box that is provided below the rotary suction table and communicates with the gap, a labyrinth section that is provided on the outer edge of the non-rotating purge box located below the rotor section, and a side blow section that supplies gas to the purge box and blows gas into the gap.

[0010] It is preferable that a rotor portion uneven portion is formed on the underside of the rotor portion corresponding to the position of the labyrinth portion, the labyrinth portion is a labyrinth portion uneven portion corresponding to the rotor portion uneven portion, and the rotor portion uneven portion and the labyrinth portion uneven portion are engaged without contacting each other.

[0011] It is preferable that the rotor portion uneven portion has a one-stage uneven portion having at least one peak and one valley, the labyrinth portion uneven portion has a one-stage uneven portion having at least one peak and one valley, and the peaks of the rotor portion uneven portion and the valleys of the labyrinth portion uneven portion are engaged with the valleys of the rotor portion uneven portion and the peaks of the labyrinth portion uneven portion without contacting each other.

[0012] It is preferable that the rotor portion uneven portion has a multi-stage uneven portion, and the labyrinth portion uneven portion has a multi-stage uneven portion.

[0013] Preferably, the gas is an inert gas.

[0014] Preferably, the non-rotating purge box has a rotating vane portion to facilitate blowing of the gas into the gap.

[0015] The number of the rotary blades is preferably 4 to 30.

[0016] It is preferable that the labyrinth portion further includes a gas seal mechanism for supplying a sealing gas thereto.

[0017] The spin treatment method of the present invention is a spin treatment method in which a substrate is subjected to a spin treatment using the spin treatment apparatus.

[0018] The method for producing a processed substrate of the present invention is a method for producing a processed substrate, which includes a processing step using the spin processing method. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a spin processing apparatus and a spin processing method that, when a processing liquid is dropped onto a rotating substrate to perform a spin processing, prevents the processing liquid and the surrounding atmosphere from flowing around to the back side of the outer periphery of the substrate, which is a significant advantage. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic side cross-sectional view of a main part of one embodiment of a spin processing apparatus according to the present invention; [Figure 2] 1 is a schematic plan view of a main part showing one embodiment of a suction pad used in a spin processing apparatus of the present invention. [Figure 3] FIG. 3 is an enlarged view of a main part of FIG. 2. [Figure 4] FIG. 2 is an enlarged view of a main part of the labyrinth portion shown in FIG. [Figure 5] 1 is a photograph showing a state in which the rotary table is removed from one embodiment of the spin processing apparatus of the present invention. [Figure 6] 1 is a photograph showing a state in which a rotating blade portion of one embodiment of a spin processing device of the present invention is viewed from below. [Figure 7] 10 is a photograph showing a state in which the rotary suction table is removed from the embodiment of the spin processing apparatus of the present invention that is equipped with a gas seal mechanism. [Figure 8] 10 is a schematic cross-sectional side view of a main part of the spin treatment device of the present invention, showing a state in which holes in the rotary blades are blocked. FIG. [Figure 9] 10 is a photograph showing the results of an example, illustrating the state in which droplets do not wrap around. [Figure 10] 10 is a photograph showing the results of a comparative example, illustrating how droplets have been wrapped around. DETAILED DESCRIPTION OF THE INVENTION

[0021] The following describes embodiments of the present invention, but these embodiments are shown by way of example only, and it goes without saying that various modifications are possible without departing from the technical spirit of the present invention. In the drawings, the same members are designated by the same reference numerals.

[0022] In Figure 1, reference numeral 10 denotes a spin processing apparatus of the present invention. The spin processing apparatus 10 is a spin processing apparatus for dropping a processing liquid used in a semiconductor manufacturing process onto a rotating substrate W to perform a spin processing. The processing liquid in this specification includes any processing liquid used in a semiconductor manufacturing process. For example, the processing liquid in this specification includes chemical liquids such as an etching liquid used in an etching process, a cleaning liquid used in a cleaning process, and a rinse liquid used in a rinse process.

[0023] The spin processing device 10 is a spin processing device including: a rotating shaft 12; a rotating support section 14 that is rotated by the rotating shaft 12 with a substrate W placed thereon; a rotor section 16 that supports the lower part of the rotating support section 14 and rotates by the rotating shaft 12; a rotating suction table 22 that has a gap G formed between an outer periphery 18 of the rotating support section 14 and an outer periphery 20 of the rotor section 16; a non-rotating purge box 24 that is provided below the rotating suction table 22 and communicates with the gap G; a labyrinth section 26 that is provided on the outer edge of the non-rotating purge box 24 located below the rotor section 16; and a side blow section 28 that supplies gas to the non-rotating purge box 24 and blows the gas into the gap G.

[0024] With this configuration, gas is sent to the gap G, which has the effect of preventing the processing liquid and the surrounding atmosphere from reaching the back side of the outer periphery of the substrate W.

[0025] The substrate W to be subjected to the spin treatment is preferably a silicon substrate or a compound semiconductor substrate such as SiC (silicon carbide), GaN (gallium nitride), or SiN (silicon nitride). The substrate W is preferably a wafer-shaped semiconductor substrate.

[0026] A spin processing apparatus that performs an etching process is suitable as the spin processing apparatus 10. In the case of a spin processing apparatus that performs an etching process, the processing liquid may be a chemical liquid such as an etching liquid, a cleaning liquid used in a cleaning process, a rinse liquid used in a rinse process, or the like.

[0027] The gas is preferably an inert gas such as nitrogen gas or argon gas.

[0028] 2 and 3 show the rotary platform 14. The rotary platform 14 is made of a suction pad and has suction holes 30. A suction hollow portion 34 formed in the rotating shaft 12 is evacuated to create a negative pressure, and the substrate W is sucked onto the rotary platform 14, which is a suction pad.

[0029] Reference numeral 32 denotes a processing liquid recovery mechanism provided to recover processing liquid that splashes or flows out when processing liquid is dropped onto the rotating substrate W for spin processing. The processing liquid recovery mechanism 32 is provided in an annular shape on the outside of the rotor unit 16, but is partially omitted in the illustrated example. The recovery mechanism described in Patent Document 1 can be used as such a processing liquid recovery mechanism.

[0030] A rotor portion uneven portion 36 is formed on the underside of the rotor portion 16 at a position corresponding to the labyrinth portion 26, and the labyrinth portion 26 is a labyrinth portion uneven portion 38 corresponding to the rotor portion uneven portion 36, and the rotor portion uneven portion 36 and the labyrinth portion uneven portion 38 are engaged without contacting each other. "Engaged without contacting" means that the rotor portion uneven portion 36 and the labyrinth portion uneven portion 38 are engaged with a small gap between them so that the rotor portion uneven portion 36 can rotate.

[0031] The rotor portion uneven portion 36 has a one-stage uneven portion 40 having at least one peak and one valley, and the labyrinth portion uneven portion 38 has a one-stage uneven portion 42 having at least one peak and one valley, and the peaks of the rotor portion uneven portion 36 and the valleys of the labyrinth portion uneven portion 38 are engaged with the valleys of the rotor portion uneven portion 36 and the peaks of the labyrinth portion uneven portion 38 without contacting each other.

[0032] An enlarged view of the labyrinth portion 26 is shown in FIG. 4. As clearly shown in FIG. 4, the labyrinth portion uneven portion 38 has a single-stage uneven portion 42 having at least one peak and one valley. In the illustrated example, the rotor portion uneven portion 36 is formed with at least two single-stage uneven portions 40, making it a multi-stage uneven portion. The labyrinth portion uneven portion 38 is also formed with at least two single-stage uneven portions 42, making it a multi-stage uneven portion. In this way, it is preferable that both the rotor portion uneven portion 36 and the labyrinth portion uneven portion 38 be multi-stage uneven portions, as this enhances the sealing effect.

[0033] 5 shows a state in which the rotary table is removed from one embodiment of the spin processing apparatus 10 of the present invention. In the illustrated example, the non-rotating purge box 24 is formed with gas holes 52 for supplying gas at four locations.

[0034] Furthermore, in the illustrated example, it is preferable that the non-rotating purge box 24 has a rotating vane section 44 for promoting the blowing of the gas into the gap G (arrow in FIG. 1). FIG. 6 is a photograph showing the rotating vane section 44 of one embodiment of the spin processing device 10 of the present invention as viewed from below. In the example of FIG. 6, an example is shown in which the rotating vane section 44 has 44 blades. It is preferable that the inclination angle of the blades of the rotating vane section 44 is 30° to 60°. It is also preferable that the number of blades of the rotating vane section 44 is 4 to 30. This is because the blades have a high gas delivery effect.

[0035] In the present invention, it is preferable to further include a gas sealing mechanism 46 that supplies a sealing gas to the labyrinth portion 26. An inert gas such as nitrogen gas or argon gas is preferable as the sealing gas, as this further enhances the sealing effect. Figure 7 shows a photograph of the embodiment of the spin processing device 10 of the present invention, with the gas sealing mechanism 46 provided and the rotary suction table 22 removed.

[0036] The spin processing method of the present invention is a spin processing method in which a substrate W is subjected to a spin processing using the spin processing device 10. Also, the method for manufacturing a processed substrate of the present invention is a method for manufacturing a processed substrate including a processing step by the spin processing method. [Example]

[0037] The present invention will be explained in more detail below by way of examples, but it goes without saying that these examples are given for illustrative purposes and should not be construed as limiting.

[0038] <Confirming the effect of the labyrinth section> As shown in FIG. 8, the rotary vane portion 44 of the spin treatment device 10 was covered with tape 48, and the effect of the labyrinth portion 26 was measured in a state where the effect of the rotary vane portion 44 was absent. For the measurements, a conventional spin processing device without a labyrinth section 26 was prepared, and the rotary adsorption table was rotated at the rotation speeds shown in Table 1 to measure the effect of the labyrinth. The flow rate of nitrogen gas from the side blow section 28 was set to 50 L / min. In Example 3, a spin processing device equipped with a gas seal mechanism 46 was used, and nitrogen gas was supplied as a sealing gas at 50 L / min from a supply source separate from the supply source to the side blow section 28. The pressure was measured by measuring the pressure inside the non-rotating purge box 24. The explanation in Table 1 is as follows: No labyrinth: No unevenness in the rotor or labyrinth Labyrinth 1-stage: The rotor and labyrinth sections are each one-stage uneven. Two-stage labyrinth: The rotor and labyrinth sections are each two-stage uneven sections. Gas seal: Nitrogen gas is supplied as sealing gas from the gas seal mechanism The results are shown in Table 1.

[0039] [Table 1]

[0040] From the results in Table 1, it was confirmed that the pressure was the highest in Example 3, and that the pressure inside the non-rotating purge box was less likely to escape to the outside even when the rotation speed of the rotary suction table increased.

[0041] <Confirming the effect of the rotating blades> In Experimental Example 1, the rotating blade unit 44 of the spin processing device 10 shown in FIG. 1 was not covered with tape 48, and the number of blades in the rotating blade unit 44 was set to 0 (no blades). In Experimental Example 2, the number of blades in the rotating blade unit 44 was set to 16. The rotary suction table was rotated at the rotation speeds shown in Table 1, and the effects of the rotating blade unit were measured. The inclination angle of the blades was all 60°. Pressure was measured by measuring the pressure inside the non-rotating purge box 24.

[0042] The flow rate of nitrogen gas from the side blow section 28 was set to 0 L / min, meaning that no gas was supplied. In addition, using a spin treatment device equipped with a gas seal mechanism 46, nitrogen gas was supplied as a sealing gas at 50 L / min from a supply source separate from the supply source to the side blow section 28. The labyrinth was two-stage (the rotor section uneven portion and the labyrinth section uneven portion each had two stages of unevenness). The results are shown in Table 2.

[0043] [Table 2]

[0044] From the results in Table 2, it can be seen that even when the rotation speed of the rotary adsorption table increased, the pressure inside the non-rotating purge box was lower in Experimental Example 2, and it was confirmed that the rotating blade section 44 caused the surrounding gas to rise, lowering the pressure inside the non-rotating purge box. This shows that Experimental Example 2, which was provided with a rotating blade section, has a higher ability to raise the surrounding gas inside the non-rotating purge box. Note that if the number of blades on the rotating blade section is too small, the effect is low, and if the number is too large, the effect is also weakened, so it is preferable to have 4 to 30 blades.

[0045] Example 4 A semiconductor substrate, a silicon single crystal wafer with a diameter of 12 inches and a standard thickness of 775 μm ± 25 μm, was placed on a rotary suction table, and a spin processing device was prepared under the same conditions as in Experimental Example 2 (two-stage labyrinth, gas seal, 16 rotating blades). The mixed acid was rotated at 800 rpm, the rinse at 1000 rpm, and the dry at 1500 rpm. The etching solution (mixed acid) was dropped onto the rotating wafer, followed by a spin processing by etching, a subsequent rinse solution was dropped, and a subsequent spin processing by drying. After these spin processing steps, the etching solution was visually inspected for penetration onto the backside of the wafer. A photograph is shown in Figure 9. No penetration of the etching solution onto the backside of the wafer was observed.

[0046] (Comparative Example 2) A conventional spin processing apparatus without a labyrinth section or rotating blades was prepared, and a spin etching process was performed in the same manner as in Example 4. After the spin processing, the etching solution was visually inspected to see if it had spread to the backside of the wafer. A photograph is shown in FIG. 10. As shown in FIG. 10, numerous droplets 50 were observed on the backside of the wafer, indicating that the etching solution had spread to the backside of the wafer. [Explanation of symbols]

[0047] 10: spin processing apparatus of the present invention, 12: rotating shaft, 14: rotating mounting section, 16: rotor section, 18: outer periphery, 20: outer periphery, 22: rotating suction table, 24: non-rotating purge box, 26: labyrinth section, 28: side blow section, 30: suction hole, 32: processing liquid recovery mechanism, 34: suction hollow section, 36: rotor section uneven section, 38: labyrinth section uneven section, 40, 42: one-stage uneven section, 44: rotating blade section, 46: gas seal mechanism, 48: tape, 50: droplet, 52: gas hole, G: gap, W: substrate.

Claims

1. A spin processing apparatus for dropping a processing liquid used in a semiconductor manufacturing process onto a rotating substrate to perform spin processing, A rotation axis; a rotary suction table including a rotary platform that is rotated by the rotary shaft with a substrate placed thereon, a rotor that supports a lower portion of the rotary platform and rotates by the rotary shaft, and a gap formed between an outer periphery of the rotary platform and an outer periphery of the rotor; a non-rotating purge box provided below the rotary suction table and communicating with the gap; a labyrinth portion provided on the outer edge of the non-rotating purge box located below the rotor portion; a side blower that supplies gas to the purge box and blows the gas into the gap; Including, Spin processing equipment.

2. 2. The spin processing device according to claim 1, wherein a rotor portion uneven portion is formed on the underside of the rotor portion corresponding to the position of the labyrinth portion, the labyrinth portion is a labyrinth portion uneven portion corresponding to the rotor portion uneven portion, and the rotor portion uneven portion and the labyrinth portion uneven portion are engaged with each other without contacting each other.

3. 3. The spin processing device according to claim 2, wherein the rotor portion uneven portion has a single-stage uneven portion having at least one peak and one valley, the labyrinth portion uneven portion has a single-stage uneven portion having at least one peak and one valley, and the peaks of the rotor portion uneven portion and the valleys of the labyrinth portion uneven portion are engaged with the valleys of the rotor portion uneven portion and the peaks of the labyrinth portion uneven portion, respectively, without contacting each other.

4. 3. The spin processing device according to claim 2, wherein the rotor portion uneven portion has a multi-stage uneven portion, and the labyrinth portion uneven portion has a multi-stage uneven portion.

5. 2. The spin processing apparatus of claim 1, wherein the gas is an inert gas.

6. The spin processing apparatus of claim 1 , wherein the non-rotating purge box has a rotating blade portion for facilitating the blowing of the gas into the gap.

7. 7. The spin processing device according to claim 6, wherein the number of said rotary vanes is 4 to 30.

8. 2. The spin processing apparatus according to claim 1, further comprising a gas seal mechanism for supplying a sealing gas to said labyrinth portion.

9. A spin treatment method, comprising: subjecting a substrate to spin treatment using the spin treatment apparatus according to any one of claims 1 to 8.

10. 10. A method for producing a processed substrate, comprising the step of treating by the spin treatment method of claim 9.

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