JP2886382B2 - Coating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus for applying a coating liquid by rotating an object such as a semiconductor wafer.

[0002]

2. Description of the Related Art Conventionally, as a coating apparatus for applying a coating liquid by rotating an object to be processed such as a semiconductor wafer, a resist rotary coating apparatus as shown in FIG. 5 has been tried. The coating apparatus includes a spin chuck 4 serving as a rotation holding unit that horizontally holds a semiconductor wafer 2 as an object to be processed and rotates at high speed.
A resist solution supply nozzle 6 for dropping a resist solution as a coating solution onto the semiconductor wafer 2; and an outer container 8 provided to surround the semiconductor wafer 2 on the spin chuck 4.
And an inner container 10. Further, below the spin chuck 4, a back surface cleaning nozzle 12 for discharging a cleaning solution for cleaning a resist solution adhered to the back surface of the wafer 2 is provided.

The resist solution dropped from the resist solution supply nozzle 6 onto the semiconductor wafer 2 is uniformly applied onto the semiconductor wafer 2 by rotation of the spin chuck 4, and excess resist solution is applied to the peripheral direction of the semiconductor wafer 2. It is scattered and adheres to the inner wall surfaces of the outer container 8 and the inner container 10. If the resist liquid layer adhering to the outer container 8 and the inner container 10 is left as it is, the resist is gradually laminated, dried, peeled off from the containers 8 and 10 by impact, and may contaminate the semiconductor wafer 2. is there. For this reason, containers 8 and 10 are regularly removed and washed and removed. However, this operation is very troublesome and time-consuming.

[0004] Therefore, in this coating apparatus, containers 8, 10
A cleaning mechanism is provided for automatically removing the resist adhering to the substrate. That is, as shown in FIGS. 5 and 6, the cups 8 and 10 are provided with an introduction path 14 for introducing a cleaning liquid L for dissolving the resist, and a cleaning liquid L introduced from the introduction path 14.
And a plurality of small holes 18 for discharging the cleaning liquid L of the liquid reservoir 16 to the resist-attached surface.
A tube 22 for introducing a cleaning liquid is connected to the introduction path 14 via a joint 20. The cleaning liquid L supplied to the liquid reservoir 16 flows out through each small hole 18 and flows down along the inner peripheral surface of the outer container 8 and the outer peripheral surface of the inner container 10. Further, as another cleaning means, as shown in FIG.
There is also known a technique in which a cleaning liquid is supplied from an upper cleaning liquid supply nozzle 20 while the spin chuck 4 is mounted and the spin chuck 4 is rotated, and the containers 8 and 10 are scattered to wash the containers 8 and 10 (Japanese Patent Laid-Open Publication No. Sho.
8-184725, JP-A-62-73630).

[0005]

However, in the former, ie, the cleaning mechanism shown in FIGS. 5 and 6, the structures of the outer container 8 and the inner container 10 are complicated, not only expensive, but also in processing and mounting. difficult. Further, although the cleaning liquid L flows from hundreds of small holes 18, the cleaning liquid L spreads easily over the entire peripheral surfaces of the containers 8, 10 because the cleaning liquid L easily flows along the path once flowing. There was a problem that the washing did not flow, resulting in uneven cleaning. Further, the cleaning operation of the containers 8 and 10 is performed by a certain number of wafers, for example, 100 to 200 wafers.
It is performed every time the resist is applied. During this cleaning operation, not only the resist application processing of the wafer cannot be performed, but also a waiting time of about 5 to 10 minutes is required to return the container whose temperature has been lowered by the cleaning to room temperature, and the throughput is increased. Is improved.

Further, there is a possibility that a trouble such as leakage of the cleaning liquid L from the joint 20 or the like may occur. In addition to the above,
It was difficult to control the direction in which the washing solution was scattered, and there was a problem that the container could not be washed effectively. On the other hand, in the latter case, that is, in the cleaning mechanism shown in FIG.
Although it is possible to shorten the cleaning time and reduce the consumption amount of the cleaning liquid, it takes time to carry in and carry out the dummy wafer 24, and also requires a standby space for the dummy wafer 24 and manual loading and unloading.
There is a problem that particles adhered to the surface of the wafer 4 adhere to the spin chuck 4 and contaminate the wafer 2. The present invention has been devised in view of the above problems and effectively solving them. An object of the present invention is to provide a coating apparatus that can simultaneously perform cleaning of the back surface of a processing target and cleaning of a container.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a rotating holding means for holding and rotating an object to be processed, and a rotating and holding means provided to surround the rotating and holding means. A coating liquid having a container for preventing the coating liquid supplied to the body from scattering; a cleaning liquid discharge nozzle for discharging a cleaning liquid toward a back surface of the processing target held by the rotation holding means; And a control unit for changing the rotation speed of the rotation holding unit when cleaning the back surface of the processing object, so that the cleaning liquid hitting the back surface of the processing object is scattered toward the wall surface of the container. It is composed.

[0008]

According to the present invention, the object to be processed held by the rotation holding means is supplied with the cleaning liquid from the cleaning liquid discharge nozzle when cleaning the back surface of the object to be processed in the final step of resist coating. While discharging, the rotation speed of the rotation holding device is increased or decreased by the control device to be changed. As a result, when the rotation speed is high, the cleaning liquid that has hit the back surface of the object to be processed is sprayed relatively horizontally by a large centrifugal force and hits the outer wall surface of the container to wash it. The cleaning liquid that has come into contact with the back surface of the processing body does not fly too far, but hits the inner wall surface of the container and cleans it. Therefore, it is possible to simultaneously perform the back surface cleaning of the object and the container cleaning.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the coating apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. 1 is a cross-sectional view showing a coating apparatus according to the present invention, FIG. 2 is a schematic plan view showing one embodiment in which the present invention is applied to a resist film forming apparatus, and FIG. 3 is a main part showing main parts of the apparatus in FIG. It is sectional drawing. The same parts as those of the conventional device are denoted by the same reference numerals. As shown in the figure, this resist film forming apparatus is used for an object to be processed, such as a semiconductor wafer 2.
(Hereinafter, simply referred to as a wafer), a processing mechanism unit 28 provided with a processing mechanism for performing various processes, and a loading / unloading mechanism 30 for automatically loading / unloading the wafer 2 into / from the processing mechanism unit 28. It is mainly composed of The loading / unloading mechanism 30 includes a wafer carrier 32 for storing the unprocessed wafer 2, a wafer carrier 34 for storing the processed wafer 2, and an arm 36 for holding the wafer 2 by suction.
A moving mechanism 38 for moving the arm 36 in X (left and right), Y (front and rear), Z (vertical) and θ (rotation) directions;
The wafer 2 is aligned and the processing mechanism unit 28
And an alignment stage 40 between which the wafer 2 is transferred.

The processing mechanism unit 28 is provided with a transfer mechanism 44 movably along a transfer path 42 formed in the X direction from the alignment stage 40. The transport mechanism 44 is provided with a main arm 46 movably in the X, Y and θ directions. On one side of the transport path 42,
An adhesion processing mechanism 48 for performing an adhesion processing for improving the adhesion between the wafer 2 and the resist liquid film.
And a pre-bake mechanism 50 for heating and evaporating the solvent remaining in the resist applied to the wafer 2, and a cooling mechanism 52 for cooling the heated wafer 2. Further, on the other side of the transfer path 42, a coating mechanism 54 for coating a resist liquid on the surface of the wafer 2 according to the present invention.
A (coating device) and a surface coating layer coating mechanism 56 for coating and forming a CEL film or the like on the resist of the wafer 2 in order to prevent irregular reflection of light during the exposure step are provided.

The coating apparatus 54 according to the present invention comprises a spin chuck 4 which is a rotation holding means for holding the wafer 2 as an object to be processed on an upper surface, for example, holding by vacuum suction and rotating. And a spin motor 58 for driving the rotation. On an upper surface of the spin chuck 4, a plurality of holding vacuum holes (not shown) connected to a vacuum pump or the like are provided. A bottom plate 62 is provided below the spin chuck 4 so that the rotation shaft 60 of the spin chuck 4 is inserted therethrough. Above the bottom plate 62, the coating liquid L2 supplied to the upper portion of the wafer 2 is prevented from scattering. Container 64 is formed. Specifically, this container 64
A first end covering the outer periphery of the spin chuck 4 and having an upper end slightly higher than the horizontal level of the spin chuck;
It is mainly composed of a container, an annular outer container 64A, a second container extending from the lower part of the spin chuck in the outer peripheral direction, and an annular inner container 64B. The outer container 64A and the inner container 64B are formed so as to be gradually inclined downward toward the outside in the radial direction of the spin chuck, and are configured to guide the coating liquid adhering to these wall surfaces toward the bottom plate 62. ing.

The bottom plate 62 is formed so as to be gently inclined in one direction.
An exhaust pipe 66 for exhausting the inside of the container is connected, and a drain pipe 68 for discharging a coating liquid flowing down in the container, a cleaning liquid described later, or the like is connected at the lowest position. Further, the bottom plate 6 slightly radially inward from the peripheral portion of the inner container 64B.
2, a partition 70 is provided in a ring shape to prevent drainage or the like from entering the inside.

A plurality of, for example, two cleaning liquid discharge nozzles 7 for discharging a cleaning liquid L such as a thinner toward the back surface of the wafer are provided below the spin chuck 4.
2A and 72B are provided. Specifically, the discharge nozzles 72A and 72B are arranged point-symmetrically about the rotation center of the spin chuck, and can effectively perform back surface cleaning even on a wafer having a large radius such as an 8-inch wafer. It is configured as follows. The number of the ejection nozzles may be one or three or more. The number of the ejection nozzles is not limited to the number. In the case of a plurality, the ejection nozzles are arranged at equal intervals along the circumferential direction of the spin chuck.
In this case, the inclination angle θ of each of the discharge nozzles 72A and 72B with respect to the vertical direction is set to, for example, about 45 °, so that the cleaning liquid scattered on the back surface of the wafer reaches the inner wall of the outer container 64A when the wafer rotates at high speed, and scatters when rotating at low speed. The cleaning liquid thus collected reaches the outer wall of the inner container 64B. The inclination angle θ is not limited to 45 °, but can be set within a range of 25 to 65 °, for example, in relation to the number of rotations with the spin chuck.

The position of the nozzle is determined so that the intersection between the extension direction of each of the nozzles 72A and 72B and the wafer 2 is separated from the outer periphery of the spin chuck 4 by a predetermined distance L3, for example, about 15 mm. Each of the discharge nozzles 72A and 72B is connected to a cleaning liquid supply unit 76 having a cleaning liquid tank, a supply pump, and the like via a pipe 74 and the like. The cleaning liquid supply unit 76 is controlled by a control signal from a control unit 78 including a microprocessor or the like in which a cleaning process or the like is programmed in advance.
The number of rotations of the spinning chuck 8 is also controlled to change the number of rotations of the spin chuck 4 from a low speed to a high speed or vice versa while the back surface cleaning operation of the wafer 2 is being performed, so that the cleaning liquid L that collides with the back surface of the wafer 2 in the horizontal direction. Is configured to be able to change the scattering angle and the like. Above the spin chuck 4, a resist liquid supply nozzle 6 for supplying a coating liquid L2 such as a resist onto the wafer 2 is provided.

Next, the operation of the embodiment configured as described above will be described. First, the unprocessed wafer 2 is unloaded from the wafer carrier 32 by the arm 36 of the loading / unloading mechanism 30 and placed on the alignment stage 40. Next, the wafer 2 on the alignment stage 40 is held by the main arm 46 of the transfer mechanism 44,
It is sequentially conveyed to each of the processing mechanisms 48 to 56 for processing.
Then, the processed wafer 2 is returned to the alignment stage 40 by the main arm 46, further transported by the arm 36, and stored in the wafer carrier 34.

In the coating apparatus 54 according to the present invention, the resist film forming operation is performed as follows. First, the wafer 2 is placed on the spin chuck 4 and is suction-held by vacuum suction. Then, by driving the spin motor 58 while holding the wafer 2, the spin chuck 4 and the wafer 2 attracted to the spin chuck 4 are rotated at a high speed of, for example, 2000 rpm. Coating liquid L
2 (resist liquid) is supplied dropwise onto the wafer 2. At this time, the atmosphere in the container 64 is exhausted with a predetermined suction force through the exhaust pipe 66. The supplied coating liquid is centrifugally applied by the rotating wafer 2 and spreads uniformly from the center of the wafer in the radial direction, and is uniformly applied to the wafer surface. And adheres to the inner wall surface of the outer container 64A and the outer wall surface of the inner container 64B. And, if left as it is, it may cause generation of particles.

When the coating process for a predetermined time is completed in this manner, the control means 78 drives the cleaning liquid supply section 76 to discharge the cleaning liquid L such as a thinner from both the cleaning liquid discharge nozzles 72A and 72B, and The back surface cleaning and side rinsing are performed to remove the coating liquid adhering thereto. At the time of performing the back surface cleaning, the spin motor 58 is controlled by the control means 78 while discharging the cleaning liquid L to change the rotation speed of the wafer 2 by increasing or decreasing the rotation speed in a range of, for example, 500 to 2000 rpm. By gradually increasing or decreasing the centrifugal force applied to the scattered cleaning liquid, the scattered cleaning liquid reaches the inner wall surface of the outer container 64A and the outer wall surface of the inner container, and cleans these surfaces.

That is, as shown in FIG. 3, when the wafer 2 is rotating at a high speed, for example, at 2000 rpm, a relatively large centrifugal force is applied to the cleaning liquid that collides with the wafer surface. While arriving at the peripheral portion of the outer container 64A, and is scattered in a substantially horizontal direction as shown by an arrow 80, adheres to the inner wall surface 82 of the outer container 64A, and is washed while flowing down this portion. Then, as the rotational speed of the wafer decreases, the scattering direction of the cleaning liquid gradually inclines downward from the horizontal direction as shown in the drawing, and the cleaning liquid also adheres to the outer wall surface 84 of the inner container 64B. In particular, when the number of revolutions of the wafer 2 is the lowest, for example, at 500 rpm, the centrifugal force applied to the cleaning liquid is considerably small. And falls down, adheres to the outer wall surface 84 of the inner container 64B, and flows down while being washed.

Such a wafer back surface cleaning operation is performed for the same time as the conventional wafer back surface cleaning operation, for example, for about 10 seconds,
Thereafter, the thinner is shaken off and dried at high speed.
Then, when the drying of the cleaning liquid is completed, the wafer 2 is transferred to the next processing mechanism. As described above, in the present embodiment, the cleaning of the back surface of the wafer and the cleaning of the wall surfaces of the outer and inner containers 64A and 64B are simultaneously performed for each operation of forming a resist film on the wafer. It is not necessary to set a cleaning time specially each time the wafer is processed and perform the vessel cleaning operation, thereby improving the throughput of the resist formation processing.

Further, in this embodiment, a complicated structure for supplying the cleaning liquid as shown in FIG. 4 to the container 64 is not required, and the structure of the container 64 can be simplified. In particular, in the present embodiment, since the cleaning liquid discharge nozzles 72A and 72B are disposed at point-symmetric positions with respect to the rotation center of the spin chuck, even if the size of the wafer becomes large, for example, 8 inches, the size of the wafer is reduced. The back surface and the wall surfaces of the outer and inner containers 64A and 64B can be reliably washed. In the above-described embodiment, the rotation speed of the spin chuck 4 is set to be changed in the range of 500 to 2000 rpm. However, the present invention is not limited to this, and the scattering direction of the cleaning liquid depends on the inclination angle θ of each of the nozzles 72A and 72B. The rotation speed of the spin chuck is determined in consideration of the inclination angle θ, and the outer and inner containers 64A, 64A
The number of rotations is controlled so that the cleaning liquid adheres to the wall surface of B.
At this time, the spin chuck 4 may be moved up and down. By doing so, the upper wall surface of the outer container 64A,
The upper wall portion of the inner container 64B can be more effectively cleaned.

Further, in the above embodiment, the inclination angle θ of the two cleaning liquid discharge nozzles 72A and 72B is set to the same value, and the number of revolutions of the wafer is changed during the cleaning of the back surface of the wafer. Although the cleaning liquid is scattered toward the outer wall surface of the inner container 64B, the cleaning liquid may be configured as shown in FIG. FIG.
The same parts as those of the apparatus shown in FIG. That is, one cleaning liquid discharge nozzle 72A
The distance L3 from the peripheral portion of the spin chuck 4 is also set to about 15 mm by setting the inclination angle θ2 of FIG. The number of rotations of the wafer 2 during the back surface cleaning operation of the wafer is also kept constant, and the scattering direction 90 of the cleaning liquid at this time is set.
Is set to be relatively close to the center of the outer wall surface of the inner container 64B.

The tilt angle θ3 of the other cleaning liquid discharge nozzle 72B is set to be larger than the tilt angle θ2 so that the discharged cleaning liquid hits substantially the center of the wafer in the radial direction. The scattering direction 92 of the cleaning liquid is set to be substantially horizontal to the wafer. That is, the inclination angle θ3 is
The angle is set so that the cleaning liquid scattered from the back surface of the wafer can reach the inner wall surface of the outer container 64A. Thus, 2
By setting the inclination angles of the two discharge nozzles 72A and 72B to be different in advance, the inner wall surface of the outer container 64A and the outer wall surface of the inner container 64B can be simultaneously formed without changing the rotation speed of the wafer at the time of cleaning the back surface of the wafer. Cleaning can be performed, and the same operation and effect as those of the above-described embodiment can be exhibited. In the present invention, the object to be processed can be applied not only to a semiconductor wafer but also to a printed circuit board, an LCD substrate, and the like. The present invention can be applied to an apparatus, a magnetic liquid application apparatus, a cleaning apparatus, and the like.

[0023]

As described above, according to the present invention, the following excellent functions and effects can be exhibited. Since the back surface cleaning of the object to be processed and the cleaning of the wall surface of the container are performed at the same time, it is not necessary to perform only the cleaning operation of the container alone as in the conventional apparatus. Therefore, the processing efficiency or production efficiency is greatly improved. Can be done. Further, since the structure of the container itself can be simplified, not only the cost of the apparatus itself can be significantly reduced, but also maintenance can be easily performed. Furthermore, the rotation speed of the rotation holding means
By gradually changing the degree, for example, by increasing the rotation speed relatively
Washing the wall of the first container by increasing the centrifugal force
And reduce the centrifugal force by lowering the rotation speed.
Effective cleaning because the walls of two containers can be cleaned
be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a coating apparatus according to the present invention.

FIG. 2 is a schematic plan view showing one embodiment in which the present invention is applied to a resist film forming apparatus.

FIG. 3 is a cross-sectional view illustrating a main part of the apparatus illustrated in FIG. 1;

FIG. 4 is a cross-sectional view showing another coating apparatus according to the present invention.

FIG. 5 is a sectional view showing a conventional coating apparatus.

FIG. 6 is a perspective sectional view of the apparatus shown in FIG. 5;

FIG. 7 is a sectional view showing another conventional coating apparatus.

[Explanation of symbols]

 Reference Signs List 2 semiconductor wafer (object to be processed) 4 spin chuck (rotation holding means) 54 coating mechanism (coating device) 58 spin motor 64 container 64A outer container (first container) 64B inner container (second container) 72A, 72B cleaning liquid discharge nozzle 76 Cleaning liquid supply unit 78 Control means 82 Inner wall surface 84 Outer wall surface L Cleaning liquid L2 Coating liquid

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 21/027 B05C 11/08 G03F 7/30 H01L 21/304 G03F 7/16

Claims (7)

(57) [Claims] 1. A rotation holding means for holding and rotating an object to be processed, and a container provided so as to surround the rotation holding means for preventing scattering of a coating liquid supplied to the object to be processed. A cleaning liquid discharge nozzle that discharges a cleaning liquid toward the back surface of the object held by the rotation holding unit, and a rotation speed of the rotation holding unit when cleaning the back surface of the object. And a control unit for changing the cleaning liquid, wherein the cleaning liquid hitting the back surface of the object is scattered toward a wall surface of the container. 2. The coating apparatus according to claim 1, wherein a plurality of the cleaning liquid discharge nozzles are formed. 3. A rotation holding means for holding and rotating the object to be processed, and a first means provided to surround the rotation holding means for preventing the application liquid supplied to the object from being scattered.
In a coating apparatus having a container and a second container, a first cleaning liquid discharge nozzle set so that a cleaning liquid discharged toward the processing object reaches the first container, And a second cleaning liquid discharge nozzle set so that the discharged cleaning liquid reaches the second container. 4. A rotation holding means for holding and rotating the object to be processed, a container provided to surround the rotation holding means for preventing the application liquid supplied to the object to be scattered, and A cleaning liquid discharge nozzle that discharges a cleaning liquid in a direction of the back surface of the processing target when the processing target is held by the rotation holding unit; A coating unit comprising: a control unit configured to gradually change a rotation speed so that the cleaning liquid that has hit the rear surface of the target object is scattered in a direction toward a wall surface of the container. 5. The coating apparatus according to claim 1, wherein an extension direction of the cleaning liquid discharge nozzle is set to pass slightly outside an outer periphery of the rotation holding unit. 6. The container comprises a first container provided so as to surround the rotation holding means, and a second container located below the rotation holding means, wherein the control means comprises a wall of the first container. 6. The method according to claim 4, wherein the rotation of the rotation holding means is set to be relatively high when cleaning the container, and the rotation of the rotation holding means is set to be relatively low when cleaning the wall surface of the second container. The coating device according to the above. 7. A rotation holding means for holding and rotating the object to be processed, a first container provided so as to surround the rotation holding means and for preventing the application liquid supplied to the object to be scattered,
A second container coaxially located in the first container below the rotation holding means, and a second cleaning liquid discharge provided to guide the cleaning liquid discharged toward the object to be processed to the entire surface of the second container. A coating device comprising a nozzle.