Cleaning jig, coating device, and cleaning method

Abstract

A cleaning fixture, which is disc-shaped, is used in a spin coating apparatus to clean a container while being held in the same spin holding device as the substrate. The spin holding device supplies a treatment liquid to a substrate held in a container and forms a film of the treatment liquid on the substrate by rotating the substrate. The cleaning fixture has a circumferential top and a circumferential bottom formed thereon, and a spray outlet is formed thereon between the circumferential top and the circumferential bottom. A plurality of holes leading to the spray outlet are formed at circumferential intervals on the circumferential bottom. The lower surface of the circumferential top is inclined upward toward the outer periphery.

Description

Technical Field

[0001] This disclosure relates to a cleaning fixture, a coating apparatus, and a cleaning method. Background Technology

[0002] Patent Document 1 discloses a cleaning fixture that can be used in a spin coating apparatus for cleaning a container. The spin coating apparatus drips a treatment liquid onto a substrate that is rotatably held inside the container and coats a film of the treatment liquid onto the substrate by rotating the substrate. The cleaning fixture has an outer peripheral surface that is formed such that when the cleaning fixture is rotated in the spin coating apparatus, it can retain the solvent supplied to the back side and guided by rotation and cause it to disperse into the container.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2010-16315 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] The technology disclosed herein enables a wider range of cleaning in the vertical direction compared to conventional methods when cleaning the interior of a container of a rotary coating apparatus.

[0008] Solution for solving the problem

[0009] One aspect of this disclosure provides a cleaning fixture, which is disc-shaped, for cleaning the container in a spin coating apparatus where a treatment liquid is supplied to a substrate held by a spin holding device disposed within a container, and a film of the treatment liquid is formed on the substrate by rotating the substrate. The cleaning fixture is characterized in that a peripheral top and a peripheral bottom are formed circumferentially around the periphery of the cleaning fixture, an outlet is formed circumferentially between the peripheral top and the peripheral bottom, a plurality of holes leading to the outlet are formed circumferentially spaced apart at intervals on the peripheral bottom, and the lower surface of the peripheral top is inclined upward toward the outer periphery.

[0010] The effects of the invention

[0011] According to this disclosure, when cleaning the container of the rotary coating apparatus, a wider range of cleaning in the height direction is possible compared to the past. Attached Figure Description

[0012] Figure 1 This is an explanatory diagram schematically showing a side cross-section of the rotary coating apparatus for the cleaning fixture involved in the application embodiment.

[0013] Figure 2 This is a top view of the cleaning fixture involved in the embodiment.

[0014] Figure 3 yes Figure 2 AA-line cross-section diagram.

[0015] Figure 4 yes Figure 2 BB line cross-section diagram.

[0016] Figure 5 yes Figure 2 CC line cross-section diagram.

[0017] Figure 6 It is shown in Figure 1 An explanatory diagram showing the positional relationship between the periphery of the cleaning fixture and the outer cup when the rotating suction cup of the rotary coating apparatus is equipped with the cleaning fixture according to the embodiment.

[0018] Figure 7 It is shown Figure 6 A diagram illustrating the situation when rotating at a relatively low speed.

[0019] Figure 8 It shows from Figure 7 The diagram illustrates the state of rotation at a relatively high speed. Detailed Implementation

[0020] In semiconductor device manufacturing processes, a coating liquid such as a photoresist is applied to a substrate, such as a semiconductor wafer (hereinafter sometimes referred to as a "wafer"). This spin coating is performed by supplying the coating liquid from above the wafer, which is held by a rotating chuck, and rotating the wafer. In this case, the coating liquid splashes from the upper surface of the wafer outwards, therefore a container is arranged to surround the wafer to catch the splashed coating liquid.

[0021] Furthermore, the coating liquid that has splashed into the container and adhered to the inner wall of the container is cleaned periodically. In this regard, according to the technology described in Patent Document 1, by maintaining the solvent supplied to the back side and guiding it through rotation and causing it to splash into the container, the inner wall of the container can be cleaned directly using the cleaning liquid from the nozzle for back side cleaning, in accordance with the usual points for spin coating of wafers.

[0022] Furthermore, for example, regarding the resist, from the perspective of recent years' etching resistance, processes are sometimes adopted to achieve a film thickness of approximately 10 μm. In this case, the resist used is, for example, a high-viscosity resist of 50 cP to 600 cP. Compared to conventional low-viscosity resists, such high-viscosity resists contain a higher solids content, and therefore, during spin coating, they sometimes scatter upwards and adhere to the top of the container, unlike in the past.

[0023] In this regard, in conventional technologies, the area that can be cleaned in the vertical direction is roughly horizontal. A technology capable of cleaning a wider area in the vertical direction is desired. Therefore, this disclosure enables a wider area to be cleaned in the vertical direction within a container compared to conventional methods.

[0024] Hereinafter, the cleaning fixture according to this embodiment will be described with reference to the accompanying drawings. Furthermore, in this specification, repeated descriptions are omitted by assigning the same reference numerals to elements having substantially the same functional structure.

[0025] <Rotary Coating Apparatus>

[0026] First, the structure of the rotary coating apparatus for cleaning containers using the cleaning fixture according to the embodiment will be described. For example... Figure 1 As shown, the rotary coating apparatus 1, which is a coating device, has, for example, a rectangular housing 2, within which a container 3 is housed. The container 3 has an outer cup 10 and an inner cup 20.

[0027] A rotary chuck 4, which horizontally holds the wafer (to be used as a substrate during coating) and the cleaning fixture 50 (described later), is provided inside the outer cup 10. The rotary chuck 4 can rotate via a shaft 5 using a drive device 6 equipped with a motor, etc., and can also move up and down (in the Z direction). The rotary chuck 4 constitutes a rotary holding device. A coating nozzle 7, which supplies coating liquid to the wafer held on the rotary chuck 4, is provided inside the housing 2. The coating nozzle 7 is as follows... Figure 1 The device shown can move along the Y direction in the figure between the standby position (shown by solid lines) and the supply position (shown by dashed lines). Furthermore, a clean air supply unit 8, such as a filter device, for supplying clean air to the container 3 is provided on the top plate of the housing 1. A downward airflow of clean air is formed by the clean air supply unit 8.

[0028] On the other hand, one or more cleaning nozzles 31 are provided on the lower surface of the rotary chuck 4. These cleaning nozzles 31, facing the back of the substrate held on the rotary chuck 4 and the cleaning fixture 50, supply cleaning fluid obliquely upwards and outwards from the center. In the illustrated example, two cleaning nozzles 31 are provided. These cleaning nozzles 31 are supported on the base portion 32. Cleaning fluid, for example, a solvent such as a coating liquid or resist solvent supplied by the coating nozzle 7, is supplied to the cleaning nozzles 31 from the solvent supply portion 33.

[0029] The outer cup 10 has a circular opening on its upper surface and is in the form of a base plate surrounding and held in the rotating suction cup 4, and a cleaning fixture 50. A cylindrical block 11 is provided at the apex of the outer cup 10, and a beveled portion 12 and an outer cylindrical portion 13 are provided downward from the block 11. The block 11 has the function of preventing the mist inside the outer cup 10 from being discharged to the outside and properly guiding the downward airflow into the outer cup 10.

[0030] On the other hand, inner cup 20 Figure 1 The device shown has an inner beveled portion 21 and an outer beveled portion 22. The inner beveled portion 21 discharges coating liquid, solvent, etc., that have scattered onto the cleaning jig 50 held on the rotating suction cup 4 and the lower surface of the substrate via a drain port 34 provided on the base portion 32. The outer beveled portion 22 allows these coating liquids, solvents, etc., to be discharged together with the coating liquid, solvent, etc., collected by the outer cup 10 through the space between the hanging wall 23 of the outer beveled portion 22 and the outer peripheral cylindrical portion 13, from a drain port 14 provided at the bottom of the outer peripheral cylindrical portion 13. Additionally, vapor, mist, etc., are also discharged. Figure 1 As indicated by the arrow, the exhaust is discharged from the exhaust section 24 through the space between the hanging wall 23 and the outer peripheral cylindrical section 13.

[0031] The rotary coating apparatus 1 is configured as described above, and through... Figure 1 The control unit 100 shown controls various operations. The control unit 100 is, for example, a computer equipped with a CPU, memory, etc., and has a program storage unit (not shown). The program storage unit stores programs for performing coating processes on the substrate in the spin coating apparatus 1, cleaning processes using the cleaning fixture 50, and the control of various drive systems such as the rotary suction cup 4, as well as the control of stopping the spraying of treatment liquid from various nozzles. Alternatively, the program may be recorded in a computer-readable storage medium and installed from that storage medium into the control unit 100. Furthermore, part or all of the program may be implemented by dedicated hardware (circuit board). The storage medium includes transient and non-transient storage media.

[0032] <Cleaning jig>

[0033] Next, the cleaning fixture 50 involved in the implementation method will be described in detail. Figure 2This is a top view of the cleaning fixture 50. Figure 3 yes Figure 2 AA line cross section diagram Figure 4 It should be Figure 2 BB line cross-section diagram Figure 5 It should be Figure 2 The CC line cross-sectional view shows that the cleaning fixture 50 has a disk-shaped overall shape, and its external dimensions, except for the thickness, are the same shape and size as the wafer.

[0034] An annular recess 52 is formed on the periphery of the upper surface of the cleaning fixture 50. A flat, annular bottom 53 facing the recess 52 is formed on the lower surface of the recess 52. Furthermore, an annular peripheral top 54 protruding outwards is provided around the entire circumference of the outer side of the annular recess 52 of the cleaning fixture 50. On the other hand, an annular peripheral bottom 55 extending from the bottom 53 and protruding outwards around the entire circumference is formed in the portion facing the peripheral top 54. Moreover, an annular nozzle 56 is formed around the entire circumference of the cleaning fixture 50 between the peripheral top 54 and the peripheral bottom 55. In this embodiment, the nozzle 56 is formed by the peripheral top 54 and the peripheral bottom 55. However, this is not a limitation; the nozzle 56 may also be formed between the peripheral top 54 and the peripheral bottom 55 by other methods.

[0035] Additionally, at the bottom edge of 55, as shown... Figure 2 , Figure 5 When viewed from above as shown, arc-shaped holes 61 are formed at equal intervals. In the cleaning fixture 50 according to this embodiment, as... Figure 2 As shown, 12 locations are formed. Figure 5 As shown, the hole 61 is formed at the bottom periphery 55 with a length extending into the interior of the nozzle 56 in the height direction. This forms a guide passage 62 leading from the inlet of the hole 61 to the nozzle 56. The nozzle 56 has an upper surface 56a and a lower surface 56b. In this embodiment, the guide passage 62 has a shape in which the cross-sectional area of ​​the flow path increases as it moves toward the nozzle 56. Furthermore, each hole 61 is formed independently to at least the lower surface 56b within each nozzle 56. And, when viewed from above, each hole 61 communicates with the lower surface 56b within the nozzle 56 at a position near the center of the cleaning fixture 50 on the lower surface 56b within the nozzle 56.

[0036] Figure 6The figure illustrates the positional relationship between the periphery of the cleaning jig 50, the block 11 of the outer cup 10, and the inner cup 20 when the cleaning jig 50 with the aforementioned structure is held by the rotating suction cup 4. As shown in the figure, the lower surface side of the peripheral top 54, i.e., the upper surface 56a within the spray nozzle 56, is inclined and tilted obliquely upwards from the horizontal plane at an elevation angle θ. This elevation angle θ can be arbitrarily set, for example, within a range of 5 degrees to 20 degrees. In this embodiment, it is set such that the lower end 11a of the block 11 is located within this elevation angle θ. According to the inventors' understanding, most of the coating liquid that is sprayed out during spin coating of the substrate adheres to the lower end 11a of the block 11 and its periphery. Furthermore, as... Figure 6 As shown, the upper end 11b of the block 11 is located at an elevation angle higher than the top of the periphery of the cleaning fixture 50 held in the rotating suction cup 4, and more specifically, higher than the position on the extension line of the upper surface 56a inside the nozzle 56. In this example, the upper end 11b of the block 11 is located higher than the range of the elevation angle θ.

[0037] <Cleaning Method>

[0038] The cleaning fixture 50 according to the embodiment has the above structure. Next, a cleaning method using the cleaning fixture 50 will be described.

[0039] First, after the wafer has undergone the prescribed coating process, it is removed from the housing 2 of the spin coater 1. Then, the cleaning fixture 50 is moved into the housing 2 and held by the rotating suction cup 4. As described, the cleaning fixture 50 has the same shape and size as the wafer except for its thickness, thus allowing direct use of the wafer transport arm. Furthermore, when the cleaning fixture 50 is not in use, it can be kept in standby locations within the coating and developing apparatus of this spin coater 1, such as a buffer section or storage container, where the wafer is stored.

[0040] Next, while rotating the cleaning fixture 50 at a relatively low speed, cleaning fluid is supplied from the cleaning nozzle 31 to the bottom 53 of the lower surface of the cleaning fixture 50. Thus, as... Figure 7 As shown, the cleaning fluid flows outward from the surface of the bottom 53, and a portion of the cleaning fluid falls onto the inner inclined surface 21 and the outer inclined surface 22 of the inner cup 20, thereby cleaning these surfaces with the cleaning fluid. The supply to the inner inclined surface 21 and the outer inclined surface 22 is controlled, for example, by the spray flow rate of the cleaning fluid and the rotation speed of the cleaning fixture 50.

[0041] In this case, the remaining portion of the cleaning fluid flowing outward from the surface of the bottom 53 enters the hole 61 of the peripheral bottom 55, flows into the entire circumference above the peripheral bottom 55, and remains in the area from the inlet of the hole 61 to the area above the peripheral bottom 55 due to surface tension, forming a pool of cleaning fluid T. In this case, when viewed from above, each hole 61 is connected to the lower surface 56b inside the nozzle 56 at a position near the center of the cleaning fixture 50, thereby allowing more cleaning fluid to accumulate from the depth of the hole 61, resulting in an increase in the amount of accumulated fluid T.

[0042] Then, once the cleaning of the inner beveled surface 21 and the outer beveled surface 22 of the inner cup 20 is complete, the cleaning fixture 50 is then rotated at a relatively high speed. Thus, as... Figure 8 As shown, the accumulated cleaning fluid T formed in the guide passage 62 from the inlet of the hole 61 of the cleaning fixture 50 is pushed outward by centrifugal force and disperses from the spray outlet 56 to the lower end 11a of the block 11 of the outer cup 10. This cleans the lower end 11a of the block 11 and its surrounding area.

[0043] Therefore, compared to current methods that disperse the cleaning fluid horizontally, a wider area can be cleaned vertically. Furthermore, as described, the cleaning fluid flows outwards along the surface of the bottom 53, and a portion of the cleaning fluid falls onto the inner inclined surface 21 and outer inclined surface 22 of the inner cup 20, thereby cleaning these surfaces. Therefore, according to this embodiment, cleaning fluid can be supplied in the dispersion directions of the block 11 and the inner cup 20 respectively, enabling efficient cleaning regardless of the contamination status of each other.

[0044] In addition, in the embodiment described above, multiple holes 61 are formed independently to the lower surface 56b inside the nozzle 56. Therefore, when the cleaning fluid rises from the bottom 53 of the cleaning fixture 50 to the lower surface 56b inside the nozzle 56, it flows in a short flow path without interfering with each other, thus making it easy to guide the cleaning fluid into the space inside the nozzle 56.

[0045] Furthermore, by adjusting Figure 6 The elevation angle θ shown can be adjusted to control the dispersion area of ​​the cleaning fluid in the height direction. In this case, the maximum elevation angle θ is such that the upper end of the outer cup 10 (in this embodiment, the upper end 11b of the block 11) is positioned higher than the position on the extension line of the lower surface side of the peripheral top 54. This more reliably prevents the mist of the cleaning fluid dispersed from the nozzle 56 from scattering to the outside of the outer cup 10.

[0046] In addition, in this embodiment, the guide passage 62 has a shape in which the cross-sectional area of ​​the flow path increases as it moves toward the nozzle 56, so it does not hinder the cleaning liquid of the accumulated liquid T from being dispersed outward by centrifugal force, thus enabling the cleaning liquid of the accumulated liquid T to be dispersed appropriately.

[0047] Furthermore, in this embodiment, the holes 61 are arc-shaped when viewed from above, but this is not a limitation; other shapes of holes can be used. Additionally, the number of holes 61 is not limited to this embodiment. Moreover, the size of the holes does not need to be all the same; a combination of large and small holes can be used. Therefore, during the cleaning process, the amount of cleaning fluid dispersed toward the outer cup 10 can be varied, allowing for an appropriate cleaning effect to be achieved based on the condition of the coating fluid adhering to the outer cup 10. Furthermore, from this perspective, the spacing of the holes 61 does not need to be equal.

[0048] Furthermore, in the described embodiment, the outward protrusion lengths of the top peripheral edge 54 and the bottom peripheral edge 55 are set to be the same, but this is not a limitation. Alternatively, the protrusion length of the bottom peripheral edge 55 may be longer than the protrusion length of the top peripheral edge 54. This allows the effluent T to disperse in an orderly manner by directing its scattering direction further upwards.

[0049] Furthermore, in this cleaning method for the outer cup 10, if the amount of cleaning fluid in the accumulated liquid T is insufficient, the cleaning fixture 50 is rotated again at a relatively low speed, and the supply of cleaning fluid from the cleaning nozzle 31 is restarted to re-form the accumulated liquid T. Then, the supply of cleaning fluid from the cleaning nozzle 31 is stopped, and the cleaning fixture 50 is rotated again at a relatively high speed. That is, it is also possible to repeat the process of relatively low rotation speed + supply of cleaning fluid from the cleaning nozzle 31, and relatively high rotation speed + stopping the supply of cleaning fluid from the cleaning nozzle 31. This solves the problem of insufficient cleaning fluid for the outer cup 10.

[0050] The embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. The above embodiments may also be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

[0051] Explanation of reference numerals in the attached figures

[0052] 1: Rotary coating device; 3: Container; 10: Outer cup; 20: Inner cup; 50: Cleaning fixture; 54: Top perimeter; 55: Bottom perimeter; 56: Spray outlet; 61: Hole; 62: Guide passage; 100: Control unit; T: Liquid accumulation.

Claims

1. A cleaning fixture, which is disc-shaped, is used in a spin coating apparatus where a treatment liquid is supplied to a substrate held by a spin holding device disposed within a container, and a film of the treatment liquid is formed on the substrate by rotation of the substrate. The cleaning fixture is characterized in that it is held in the same state as the substrate in the spin holding device. The cleaning fixture has a circumferential top and a circumferential bottom formed around its periphery. An exhaust port is formed around the entire circumference between the top and bottom of the periphery. Multiple holes leading to the nozzle are formed at circumferential intervals at the bottom periphery. The lower surface of the top of the periphery slopes upward toward the outer periphery. The hole is formed at the bottom of the periphery with a length extending into the interior of the nozzle in the height direction, and the hole is formed vertically along the height direction.

2. The cleaning fixture according to claim 1, characterized in that, The nozzle is formed through the top and bottom of the periphery.

3. The cleaning fixture according to claim 1, characterized in that, The guide passage formed between the inlet of the orifice and the outlet has a shape in which the cross-sectional area of ​​the flow path increases as it moves toward the outlet.

4. The cleaning fixture according to any one of claims 1 to 3, characterized in that, The hole appears as an arc when viewed from above.

5. The cleaning fixture according to any one of claims 1 to 3, characterized in that, Compared to the top of the perimeter, the bottom of the perimeter protrudes outward.

6. The cleaning fixture according to any one of claims 1 to 3, characterized in that, Multiple holes are formed independently to the lower surface of the nozzle.

7. The cleaning fixture according to any one of claims 1 to 3, characterized in that, When viewed from above, the hole communicates with the lower surface inside the nozzle at a position near the center of the cleaning fixture on the lower surface inside the nozzle.

8. A coating apparatus for supplying a coating liquid to a substrate within a container and forming a film of the coating liquid on the substrate by rotating the substrate, the coating apparatus comprising: A rotating holding device, disposed within the container, is capable of holding the disc-shaped cleaning fixture and the substrate to which the coating liquid is supplied in the same manner; and The cleaning nozzle supplies cleaning fluid to the lower surface of the cleaning fixture, which is held and rotated by the rotating holding device, to clean the inside of the container. wherein, The cleaning fixture has a circumferential top and a circumferential bottom formed around its periphery. An exhaust port is formed around the entire circumference between the top and bottom of the periphery. Multiple holes leading to the nozzle are formed at circumferential intervals at the bottom periphery. The lower surface of the top of the periphery slopes upward toward the outer periphery. The hole is formed at the bottom of the periphery with a length extending into the interior of the nozzle in the height direction, and the hole is formed vertically along the height direction.

9. The coating apparatus according to claim 8, characterized in that, In the cleaning fixture, the guide passage formed between the inlet of the hole and the outlet has a shape in which the cross-sectional area of ​​the flow path increases as it moves toward the outlet.

10. The coating apparatus according to claim 8, characterized in that, The hole appears as an arc when viewed from above.

11. The coating apparatus according to any one of claims 8 to 10, characterized in that, Compared to the top of the perimeter, the bottom of the perimeter protrudes outward.

12. The coating apparatus according to any one of claims 8 to 10, characterized in that, The container has a cup surrounding the cleaning fixture. A cylindrical block is provided at the upper part of the cup. The upper end of the block is positioned above the elevation angle of the top periphery of the cleaning fixture held in the rotating holding device.

13. The coating apparatus according to claim 12, characterized in that, The lower end of the block is located within the range of the elevation angle of the top of the perimeter.

14. The coating apparatus according to claim 12, characterized in that, The cup has a sloping section and an outer cylindrical section connected downwards from the block. The container has an inner cup located below the cleaning fixture held in the holding device and inside the outer cylindrical portion. The cleaning fluid is supplied to the block through the hole. The cleaning fluid is supplied to the inner cup through the bottom of the cleaning fixture outside the hole.

15. A cleaning method, comprising cleaning the container of the rotary coating apparatus using a cleaning fixture according to any one of claims 1 to 7, the cleaning method comprising the following steps: In step (A), while the cleaning fixture is held in the rotating holding device, cleaning fluid is supplied from the lower surface side of the cleaning fixture to the outside while the cleaning fixture is rotated at a relatively low speed, so that the cleaning fluid at least reaches the hole and forms a liquid accumulation in the hole; and In step (B), the cleaning fixture is rotated at a relatively high speed after the supply of the cleaning fluid has been stopped.

16. The cleaning method according to claim 15, characterized in that, In step (A), a portion of the supplied cleaning fluid is used to clean the area below the cleaning fixture inside the container.

17. The cleaning method according to claim 15 or 16, characterized in that, Repeat steps (A) and (B).

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