JPH07256194A - Cup rotation type spin coater - Google Patents

Abstract

PURPOSE:To suppresses soaring up of mists according to rotation of an inner cup internally housing a coating film forming plate and improve the yield, etc., of a cup rotation type spin coater housed with this inner cup in an outer cup by installing an outward facing flange to the lower part on the outside of the inner cup. CONSTITUTION:A substrate is set on a holding base by opening a cap 18 of an inner cup body 17 and a coating liquid is dropped to the central part on the substrate; thereafter, the cap 18 is closed and the inner cup body 17 and the holding base are respectively rotated at a high speed, by which the coating film having the uniform film thickness and high quality is formed on the substrate. A part of the coating liquid splashed from the substrate by centrifugal force is discharged from a small hole 17a formed in the outer peripheral part at the bottom end of the inner cup body 17 into the outer cup body 20. Further, a part of the coating liquid suspended in the form of the mists is discharged from a discharge duct. The outward facing flange 17b is installed to the lower part on the outside of the inner cup body 17, by which the soaring up of the mists is prevented. As a result, the number of the suspended mists is decreased and a clean state is maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cup spinner spin coater, and more particularly to a cup spinner spin coater used for forming a resist film on a wafer or the like serving as an IC substrate. The present invention relates to a cup rotary spin coater suitable for efficiently eliminating mist generated therein and forming a high quality coating film.

[0002]

2. Description of the Related Art A spin coater drops a coating solution on the central portion of a substrate held horizontally, rotates the substrate at a high speed, and expands the coating solution to the outer peripheral side of the substrate by the centrifugal force accompanying the high speed rotation. To form a uniform coating film.
It is roughly classified into a cup fixed type spin coater and a cup rotating type spin coater.

As shown in FIG. 5, the cup-fixed spin coater 50 is a spinner for rotating a coating cup 51 having an open upper portion and fixedly grounded and a substrate holding base 53 in the coating cup 51 by a drive motor 54. 52, and an exhaust hose 55 for exhausting the air in the application cup 51 is connected to the bottom of the application cup 651.

Therefore, if the substrate 56 such as a wafer is set on the substrate holding table 53, and the substrate holding table 53 is rotated at a high speed by the spinner 52 after dropping the coating solution such as photoresist, as described above, the centrifugal force is applied. Can form a coating film. However, as the substrate 56 rotates, a turbulent air flow is generated in the coating cup 51, and the solvent contained in the coating liquid is non-uniformly vaporized due to the influence of the turbulent air flow. There is an inconvenience that it cannot be done.

In order to solve the above-mentioned inconvenience caused by the cup fixed spin coater 50, a cup rotary spin coater 60 having a structure shown in FIG. 6 has been proposed. In this cup rotation type spin coater 60, a substrate holding base 63 which is rotationally driven by a spinner 62 is housed in an inner cup 61 composed of an inner cup body 61a and an openable / closable lid 61b, and a substrate 66 is mounted on the substrate holding base 63. After holding, the inner cup 61
When the lid 61b is closed and the substrate 66 is rotated by the spinner 62, the inner cup 61 is also configured to rotate in synchronization with the substrate 66.

Accordingly, the cup fixed type spin coater 5
Unlike 0, turbulent airflow can be effectively prevented from being generated around the substrate 66 even when the substrate 66 is rotated, and a coating film having a uniform film thickness can be formed.

[0007]

In the cup rotary spin coater described above, as shown in FIG. 6, the excess coating liquid scattered around the periphery of the substrate 66 by the centrifugal force accompanying the rotation of the substrate 66 The exhaust cup 6 surrounding the periphery of the cup body 61a via the discharge nozzle 64 provided in the cup body 61a.
It is designed to be discharged from 5.

However, with such a structure, the scattered excess coating solution cannot be completely removed, and a part thereof floats above the inner cup 61 as a mist. Then, when the lid of the inner cup 61 is opened and the substrate 66 is taken out after the coating film is formed, the inner cup body 6 has a slight negative pressure.
The floating mist is sucked into the inside of the la 1a and adheres to the surface of the coating film formed on the substrate 66, resulting in deterioration of product quality.

In order to prevent the excess coating liquid from scattering, the inner cup 61 is surrounded by an outer cup or the like which is fixedly arranged. In this case, however, all the floating mist is removed. Since it stays in the cup, the floating mist concentration around the inner cup 61 becomes high, and the yield of the products deteriorates. In order to eliminate the above-described inconvenience of the cup rotary spin coater, the present inventors provide a feed / discharge mechanism for forming a downflow in the outer cup at least during rotation of the inner cup, and the downflow of the inner cup We considered a cup spinner spin coater that efficiently removes floating mist existing above and further improves the yield of products.

If the cup rotation type spin coater having such a structure is adopted, it is possible to prevent the floating mist from rising due to the downflow, but it is possible to eliminate the rising of the mist accompanying the rotation of the inner cup 61. I can't. Therefore, the yield of products cannot be sufficiently improved.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a cup rotary spin coater capable of further improving the removal of floating mist and thus significantly increasing the yield of products. I am trying.

[0012]

According to a first aspect of the present invention, there is provided a cup rotary spin coater in which an outer flange member is provided on a lower outer portion of an inner cup. The cup rotary spin coater according to claim 2 employs a horizontally projecting flange member, and the projecting length of the outward flange member is
It is set to be longer than the radial gap between the inner cup and the outer cup.

The cup rotary spin coater of claim 3 is
The diameter of the lid that can open and close the inner cup is set to be larger than the outer diameter of the inner cup body. In the cup rotating spin coater of the fourth aspect, the upper end of the fixed portion of the outer cup is located above the upper end of the openable / closable lid of the inner cup. The cup rotary spin coater according to claim 5, wherein an outward flange member is provided on a lower outer portion of the inner cup, and a diameter of a lid for opening and closing the inner cup is set to be larger than an outer diameter of the inner cup body. Is.

[0014]

According to the cup rotating type spin coater of claim 1, when the inner cup is rotating, the mist accompanied by the rotation of the inner cup is greatly raised by the centrifugal force caused by the outward flange member. Can be suppressed. According to the cup rotary spin coater of claim 2, when the inner cup is rotating, the mist that accompanies the rotation of the inner cup soars that the protrusion length is larger than the gap between the inner cup and the outer cup. The long outward flange member can further suppress it.

According to the cup rotating type spin coater of the third aspect, when the inner cup is rotating, the mist accompanying the rotation of the inner cup rises to a value larger than the outer diameter of the inner cup body. It can be significantly suppressed by the centrifugal force caused by the lid. According to the cup rotating type spin coater of claim 4, when the inner cup is rotating, the mist accompanying the rotation of the inner cup is soared and the lid having a diameter larger than the outer diameter of the inner cup body and this The fixed portion of the outer cup, the upper end of which is located above the lid, can further suppress it.

According to the cup rotating type spin coater of claim 5, when the inner cup is rotating, the mist accompanying the rotation of the inner cup is soared by the centrifugal force due to the outward flange member, and the internal force. It can be significantly suppressed by the centrifugal force caused by the lid having a diameter larger than the outer diameter of the cup body.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings showing embodiments. FIG. 1 is a schematic view showing an embodiment of the cup rotary spin coater of the present invention.
5, a spin coater body 10 including an inner cup drive unit 11 and an outer cup 19, a forced exhaust mechanism 30, and a forced intake mechanism 40.

The inner cup drive unit 11 rotates the inner cup 15 at a high speed (for example, 1500 rpm) while holding the substrate on which the coating film is to be formed horizontally.
It is composed of a C servo motor 12, a rotary shaft 13 and a bearing 14. The DC servomotor 12 then inserts the inner cup 15 into the inner cup 15 via the rotating shaft 13 instructed to rotate by the bearing 14.
The inner cup 15 can be rotated with high precision and at high speed.

The inner cup 15 rotates integrally with the substrate holder 16, and is composed of the substrate holder 16, the inner cup body 17 and a lid 18 which can be opened and closed. The inner cup body 16 is a container having a short cylindrical shape with a bottom, and the bottom portion is fixed to the rotating shaft 13. Further, small holes 17a communicating with the outside are formed at several locations on the outer peripheral portion of the lower end of the inner cup body 17.

The lid 18 of the inner cup body 17 has a drive shaft 18a for opening and closing supported at the center thereof.
The lid 18 can be opened and closed by vertically moving a. The outer cup 19 includes an outer cup body 20 that houses the inner cup 15, a lid 21 that can be opened and closed, and the lid 21.
And the driving means 22 of the outer cup 1
A forced exhaust mechanism 30 and a forced intake mechanism 40 are connected to 9.

The outer cup body 20 is a container having a short cylindrical shape with a bottom that is slightly larger than the inner cup 15, and the rotary shaft 13 of the inner cup drive unit 11 penetrates through the center of the bottom portion. However, the outer cup body 20 and the rotating shaft 13 are not connected. Therefore, the inner cup 15 and the substrate holder 15 can be freely rotated in the outer cup 20. Further, the peripheral portion of the bottom portion of the outer cup body 20 is lower than the central portion.

The lid 21 of the outer cup body 20 has an air supply chamber 21a which is in communication with the air supply side of the forced air supply / exhaust mechanism 30, and the gas in the air supply chamber 21a is covered over almost the entire lower surface. It has a blow-out port consisting of a number of punching holes for blowing out. The driving means 22 is composed of an elevating cylinder, the lid 21 is connected to the piston rod of the elevating cylinder, and the lid 21 is moved up and down as the piston rod moves back and forth.

A drive shaft 18a for opening and closing the lid 18 of the inner cup body 17 is slidably penetrated through the central portion of the lid 21, and the lid 21 and the lid 18 can be opened and closed independently. it can. With the lid 21 closed, the lid 21
The outer cup body 20 is not in contact with the outer cup body 20, and the labyrinth seal 19a (see also FIG. 2) maintains the sealing performance. Therefore, it is possible to prevent dust from being generated due to the contact between the lid 21 and the outer cup body 20.

Further, the outer cup 19 is provided with a nozzle for coating liquid drop (not shown). The nozzle for coating liquid drop is always retracted between the outer cup body 20 and the inner cup body 17, and the nozzle for coating liquid drop rotates the inner cup 15 with the lid 18 of the inner cup body 17 opened. The coating liquid can be dropped onto the substrate by moving it to the center.

The forced air supply / exhaust mechanism 30 includes an air supply fan 31.
a, air supply duct 32a, open / close valve 33a, flow meter 34
a and a filter 35a, and an exhaust fan 31b, an exhaust duct 32b, and an exhaust means 30b including flow rate adjustment dampers 33b and 34b for adjusting the supply / exhaust balance. A flow can be formed.

The forced air supply mechanism 40 is composed of an air supply fan 41, an air supply duct 42, an opening / closing valve 43, a flow meter 44 and a filter 45. The end of the air supply duct 42 is connected to the lid 21 of the outer cup 19. Through the inner cup body 17
Is located near the upper end of the. FIG. 2 is an enlarged view of an essential part showing the relationship between the inner cup 15 and the outer cup 19, which is located at a predetermined outer peripheral position of the inner cup body 17, that is, above the small hole 17a and from the labyrinth seal 19a of the outer cup 19. Also, an outward flange member 17b is provided at a predetermined position below. Here, the protruding length of the outward flange member 17b may be 2 mm or more, but is preferably set longer than the radial gap c between the outer cup 19 and the inner cup body 17. Specifically, for example, when the outer diameter of the inner cup body 17 is 550 to 600 mm and the gap between the outer cup 19 and the inner cup body 17 is 5 mm, the protruding length of the outward flange member 17b is 8 mm. Set to. By thus providing the outward flange member 17b, even if there is a mist or the like floating below the inner cup 15, centrifugal force that occurs in the peripheral portion of the outward flange member 17b when the inner cup 15 rotates. By force, the mist is forcibly scattered in the space below the labyrinth seal 19a, and the mist passes through the gap between the inner cup body 17 and the outer cup 19 and the upper portion of the inner cup 15 and the outer cup body 2
It is possible to effectively prevent soaring to the lid 21 of 0.

The operation of the cup rotation type spin coater having the above-mentioned structure is as follows. Open the lid 18 and hold the substrate holder 1
6, a substrate (not shown) is set, the coating liquid is dropped onto the central portion of the substrate by a nozzle (not shown) for lowering coating liquid droplets, then the lid 18 is closed and the inner cup 15 and the substrate holder 16
By rotating at high speed, a high-quality coating film having a uniform film thickness can be formed on the substrate as follows.

That is, the inner cup 15 and the substrate holder 16
By rotating at a high speed, turbulent air flow is not generated inside the inner cup 15, so that a coating film having a uniform film thickness can be formed on the substrate. Further, during coating film formation, a part of the coating liquid is scattered from the substrate by the centrifugal force, but the scattered coating liquid enters the outer cup 19 through the small holes 17a formed in the lower outer periphery of the inner cup body 17. The discharged coating liquid becomes a mist and floats. Then, the floating mist is effectively guided to the lower portion of the outer cup 19 by the downflow generated by being forcibly supplied and exhausted into the outer cup 19, and further, the exhaust duct 32.
It is discharged together with gas such as air and nitrogen through b. Therefore, when the downflow is not formed, the inner cup 1
The number of fine mist floating above 5 was tens of thousands per cubic foot (0.028316 m3), but it can be reduced to about 2,000 by forming the downflow. it can. In this embodiment, the inner cup body 17 has an outward flange member 17b.
Since the mist is prevented from rising, the number of floating mists can be reduced to about 100 to 200 per cubic foot. This is a clean room, a clean state of about class 100.

Therefore, when the lid 18 of the inner cup body 17 is opened and the substrate is taken out after the coating film forming process is completed, almost no floating mist adheres and the quality of the coating film is set to the state at the time of coating film formation. Can be maintained.

[0030]

[Embodiment 2] FIG. 3 is a schematic view showing a main part of another embodiment of the cup rotary spin coater of the present invention. The difference from the embodiment of FIG. 2 is that the outward flange member 17b is omitted.
The only difference is that the diameter of the lid 18 is set larger than the outer diameter of the inner cup body 17. Here, the diameter of the lid 18 is preferably set to be larger than the outer diameter of the inner cup body 17 by 4 mm or more, and the lid 18 serves as a fixed portion of the outer cup 19 (a lower member of the labyrinth seal 19a in FIG. 3). It is preferably located below the upper end. Specifically, the diameter of the lid 18 is set to be 1 mm smaller than the outer diameter of the inner cup body 17.
The size is set to be larger by 5 mm, and the lid 18 is positioned 5 mm below the upper end of the fixed portion of the outer cup 19. If the vertical distance between the upper end of the fixed portion of the outer cup 19 and the lid 18 is increased, the effect of preventing floating mist from rising can be enhanced, but a substrate handling portion (not shown).
Considering the possibility of interference with 5 to 10 mm
It is preferable to set it to a degree.

Therefore, in the case of this embodiment, when the floating mist tries to soar through the gap between the outer cup 19 and the inner cup 15, the centrifugal force is caused by the rotation of the lid together with the inner cup body 17. Most of the floating mist that tries to soar with the force is scattered toward the inner surface of the outer cup 19 and can be effectively guided to the lower portion of the outer cup 19 by the downflow. Of course, the floating mist guided to the lower part of the outer cup 19 is air through the exhaust duct 32b,
Exhausted with gas such as nitrogen. As a result, the inner cup 1
It is possible to reduce the density of the floating mist above 5 and to remarkably suppress the disadvantage that the floating mist adheres to the coating film when the substrate is taken out and deteriorates the quality.

[0032]

[Embodiment 3] FIG. 4 is a schematic view showing a main part of still another embodiment of the cup rotary spin coater of the present invention.
The difference from the embodiment is that the diameter of the lid 18 is changed to the inner cup body 1
7 is the only point set larger than the outer diameter. here,
The diameter of the lid 18 is preferably set to be 4 mm or more larger than the outer diameter of the inner cup body 17, and the lid 18 is larger than the upper end of the fixed portion of the outer cup 19 (the lower member of the labyrinth seal 19a in FIG. 3). It is preferably located below. Specifically, the diameter of the lid 18 is set to be 15 mm larger than the outer diameter of the inner cup body 17, and the lid 1 is placed 5 mm below the upper end of the fixed portion of the outer cup 19.
Position 8. It should be noted that if the vertical distance between the upper end of the fixed portion of the outer cup 19 and the lid 18 is increased, the effect of preventing floating mist from rising can be enhanced, but interference with the substrate handling unit (not shown) will occur. Considering the possibility of occurrence, it is preferable to set it to about 5 to 10 mm.

Therefore, in the case of this embodiment, the density of the floating mist above the inner cup 15 can be further reduced by the synergistic effect of the outward flange member 17b and the lid 18, and the coating film can be taken out when the substrate is taken out. It is possible to almost completely eliminate the inconvenience that the floating mist adheres to and deteriorates the quality. The outward flange member 17b in the embodiment of FIGS. 2 and 4 may be formed continuously over the entire circumference, but is divided into a plurality of parts for convenience of external attachment. Alternatively, a slight gap may be provided between these divided portions.

[0034]

According to the first aspect of the present invention, when the inner cup is rotating, the mist that accompanies the rotation of the inner cup is significantly suppressed by the centrifugal force caused by the outward flange member. Therefore, it is possible to significantly reduce the possibility that floating mist adheres when the product is taken out, and to maintain the high quality of the product.

According to the second aspect of the present invention, when the inner cup is rotating, the mist that accompanies the rotation of the inner cup is soared that the outer length of the protrusion is longer than the gap between the inner cup and the outer cup. By the direction flange member, it is possible to further greatly suppress the possibility that floating mist may be attached when taking out the product, and it is possible to maintain a high quality of the product.

According to the third aspect of the present invention, when the inner cup is rotating, the mist accompanying the rotation of the inner cup is soaring that the centrifugal force is caused by the lid having a diameter larger than the outer diameter of the inner cup body. It has a unique effect that it can be significantly suppressed by force, and that the possibility of floating mist adhering at the time of taking out the product can be greatly reduced and the quality of the product can be maintained high.

According to the fourth aspect of the present invention, when the inner cup is rotating, the mist accompanying the rotation of the inner cup is soared that the lid having a diameter larger than the outer diameter of the inner cup body and the lid. It is said that the fixed part of the outer cup, whose upper end is located above, can further suppress it, which in turn can significantly reduce the possibility of floating mist adhering when taking out the product and maintain high product quality. Has a unique effect.

According to the fifth aspect of the present invention, when the inner cup is rotating, the mist accompanying the rotation of the inner cup is soared by the centrifugal force caused by the outward flange member and the outer diameter of the inner cup body. It has a unique effect that it can be significantly suppressed by the centrifugal force caused by the lid having a larger diameter.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a cup rotary spin coater of the present invention.

FIG. 2 is an enlarged view of a main part showing a relationship between an inner cup and an outer cup.

FIG. 3 is a schematic view showing a main part of another embodiment of the cup rotary spin coater of the present invention.

FIG. 4 is a schematic view showing a main part of still another embodiment of the cup rotary spin coater of the present invention.

FIG. 5 is a schematic view showing a configuration of a conventional cup fixed spin coater.

FIG. 6 is a schematic view showing a configuration of a conventional cup rotary spin coater.

[Explanation of symbols]

 11 Inner cup drive unit 15 Inner cup 17 Inner cup body 17b Outward flange member 18 Lid 19 Outer cup 21 Lid

Claims (5)

[Claims] 1. An inner cup (15) containing a coating film forming plate therein and having an openable / closable lid (18).
And an inner cup driving part (11) for holding the inner cup (15) horizontally and rotating it at a predetermined speed, and an outer cup that contains the inner cup (15) and has a lid (21) that can be opened and closed. (19) A cup rotary spin coater comprising: an inner cup (15) provided with an outward flange member (17b) on a lower outer side thereof. 2. The outward flange member (17b) is a member protruding in the horizontal direction, and the outward flange member (17b) is provided.
The protruding length of b) is such that the inner cup (15) and the outer cup (1)
The cup rotary spin coater according to claim 1, which is set to be longer than a radial gap with respect to 9). 3. An inner cup (15) containing a coating film forming plate therein and having an openable / closable lid (18).
And an inner cup driving part (11) for holding the inner cup (15) horizontally and rotating it at a predetermined speed, and an outer cup that contains the inner cup (15) and has a lid (21) that can be opened and closed. (19) is a cup rotary spin coater, characterized in that the diameter of the lid (18) capable of opening and closing the inner cup (15) is set larger than the outer diameter of the inner cup body (17). Cup rotary spin coater. 4. The upper end of the fixed portion of the outer cup (19) is
The cup rotary spin coater according to claim 3, wherein the inner cup (15) is located above the upper end of the openable lid (18). 5. An inner cup (15) which houses a coating film forming plate therein and has a lid (18) which can be opened and closed.
And an inner cup driving part (11) for holding the inner cup (15) horizontally and rotating it at a predetermined speed, and an outer cup that contains the inner cup (15) and has a lid (21) that can be opened and closed. (19) In the cup rotary spin coater including (1), an outward flange member (17b) is provided on the outer lower portion of the inner cup (15), and a lid (18) for opening and closing the inner cup (15) is provided. A cup rotary spin coater having a diameter larger than the outer diameter of the inner cup body (17).