JPH034961A - Coating apparatus - Google Patents

Abstract

PURPOSE:To obtain a clean body to be treated while preventing the contamination of the rear of an object to be coated due to the generation of particles accompanying friction by connecting a support stand to a rotary drive mechanism through a transmission means buffering a change of a rotational speed to transmit the same. CONSTITUTION:The chuck 4 connected to a motor 1 is connected to the rotary shaft 2 of the motor 1 through a transmission means 3 buffering a sudden change of a rotational speed such as a fluid joint or a spring. Therefore, even when a sudden change is generated in the number of rotations of the motor 1, the acceleration applied to the chuck 4 is reduced and the force sucking a wafer W by the chuck 4 is made relatively larger than the force received by the sudden change in the number of rotations to certainly suck the wafer W and the generation of the shift of rotation accompanying the sudden change of the number of rotations between the wafer W and the chuck 4 is prevented. As the result, the rear contamination of the wafer W due to the generation accompanying the friction between the chuck 4 and the wafer W is eliminated and a clean body to be treated can be prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coating device for processing liquids such as resist and developer.

[Prior Art and Problems to be Solved by the Invention] Conventionally, in the resist coating process in the semiconductor wafer manufacturing process, a certain amount of resist is dropped onto a wafer rotating at high speed from a nozzle provided on the wafer.

A spin coater is used to apply a resist film of uniform thickness. Further, in the step of exposing and developing a desired pattern after resist coating, a spin developer is used, which performs development, washing, and cleaning by dropping a certain amount of developer onto a wafer that is rotating at high speed.

Here, spin coaters and spin developers support the wafer with a chuck that is connected to a rotation drive mechanism such as a motor and equipped with a suction port of a vacuum pump that adsorbs the wafer. It applies the resist or developer dropwise to achieve uniform coating. At this time, the motor rotates to first spread the dropped resist, etc. to the center, and then changes the rotation speed as it coats the periphery to spread the resist and developer over the entire area. There is.

If the rotational speed of the motor is suddenly changed, for example, at the start of rotation, the wafer will accelerate rapidly if the speed from the center coating to the peripheral area is changed from 2000 rpm to 4000 rpm during coating. When the chuck rotates faster than the wafer, the wafer creates resistance in the opposite direction to the rotation direction and does not rotate at the same time as the chuck. Conversely, when the speed is reduced to 1, the wafer rotates faster than the chuck, causing a discrepancy between the wafer rotation speed and the chuck rotation speed. As a result, in either case, particles are generated due to scratches due to friction between the wafer and the chuck at the interface between the wafer and the chuck. Usually, the material used for the chuck is a relatively soft resin such as Delrin or Teflon (trade name), which has good adhesion to the wafer during chucking and does not damage the back side of the wafer. ing. For example, when a resin such as Delrin is used as a material for the chuck, Delrin is much softer than silicon, so between the chuck and the wafer, Delrin particles are pressed onto the backside of the wafer or enter the recesses on the backside of the wafer, causing contamination on the backside of the wafer. It becomes.

The present invention has been made to solve the above-mentioned drawbacks.
Even when the rotational speed of the high-speed chuck changes rapidly, there is no difference in rotational speed between the support base and the workpiece, which prevents wafer damage due to particles generated due to friction between the support base and the workpiece. An object of the present invention is to provide a coating device that does not cause backside contamination.

[Means for Solving the Problems] In order to achieve the above object, the coating apparatus of the present invention provides a coating apparatus that performs rotational coating by providing an object to be coated on a support stand connected to a rotational drive mechanism. is connected to the rotary drive mechanism via a transmission means that buffers and transmits changes in the rotational speed of the rotary drive mechanism.

[Function] In the coating device of the present invention, the chuck connected to the rotational drive mechanism is connected to the rotating shaft of the rotational drive mechanism via a means for buffering and transmitting sudden changes in rotational speed, such as a fluid coupling or a spring. Therefore, even if there is a sudden change in the rotational speed of the rotary drive mechanism, the acceleration applied to the support base is reduced, and the force with which the support base attracts the object to be coated is relatively stronger than the force received due to a sudden change in the rotational speed. By increasing the size, the object to be coated can be reliably supported by the support base, and rotational deviation due to sudden changes in rotational speed will not occur between the object to be coated and the support base. Therefore, since the support base and the object to be coated perform the same rotational movement, the support base rotates while fixing the object to be coated, and there is no difference in rotational speed between the support stand and the object to be coated. Therefore, there is no contamination of the back surface of the object to be coated due to generation of particles due to friction between the support base and the object to be coated, and a clean object to be treated can be manufactured.

[Example] An example in which the coating apparatus of the present invention is applied to a resist coating apparatus for semiconductor wafers will be described with reference to the drawings.

The resist coating apparatus shown in the configuration diagram of FIG. 1 mounts and fixes a semiconductor wafer W by vacuum suction or the like, and transmits a transmission means 3 to a rotating shaft 2 of a motor 1, which is a rotational drive mechanism, while buffering changes in rotation speed. A nozzle 5 for dropping a resist droplet is provided above the central portion of the chuck 4, which has a disk shape on the upper surface and is fixed via the chuck 4. If dispensing from the nozzle is not performed for a predetermined period of time due to a break in a lot, for example, the nozzle 4 needs to be retracted from above the chuck 4 to an outer position. It is movable. The nozzle 5 is connected to a liquid supply system 6 which is a resist supply device.

The liquid supply system 6 includes a pump such as a bellows pump that supplies a desired constant amount of the resist stored in the resist storage container.
A filter container, a valve that is opened and closed in conjunction with the pump, and a suck-back valve that pulls the resist back into the nozzle 5 after discharging the resist from the nozzle 5 to prevent dripping or assimilation of the resist are provided. Further, a cup 7 serving as a processing container is provided around the wafer W to prevent the resist from scattering outside the apparatus during resist application. The cup 7 is movable up and down, and is configured to be lowered from the position shown in the figure when loading the wafer W, exposing the chuck 4 and facilitating loading. A pipe or the like (not shown) is connected.

Here, the transmission means 3 for controlling the rotational speed of the rotational drive mechanism of the present invention, that is, for buffering changes in the number of rotations per unit time and transmitting the changes to the chuck, will be explained.

The means for buffering the change in rotation speed and transmitting it to the chuck is the second one.
It may also be a fluid coupling as shown in the figure.

In the fluid coupling, a pair of disks 8 and 9 having a fixed area are placed in the middle of the rotating shaft 2 of the motor 1 with viscous oil 10 interposed therebetween, and the oil generated by the rotation of the disk 8 connected to the motor 1 Rotation occurs in the disk 9 connected to the chuck 4 in conjunction with the eddy flow of 1o. Therefore, a sudden change in the rotation of the motor 1 is transmitted from the disk 8 to the disk 9 gradually with a time difference.

In addition, a spring joint can also be suitably used as a means for buffering and transmitting other changes in rotational speed to the chuck. As shown in Figures 3 and 4, the spring 1 is connected between the discs 8 and 9.
1.12, so that sudden changes in the rotation of the motor 1 can be buffered and gradually transmitted to the chuck 4.

In addition, as other joints, the rotating shaft 2 of the motor 1 and the chuck 4
The rotating shafts of the two may be connected by a belt.

The operation using the coating apparatus configured as above will be explained.

When a certain amount of resist is sent from the resist supply system 6 and dropped from the nozzle 5 onto the center of the wafer W,
As shown by the solid line in the graph of the relationship between rotational speed and time in FIG. 5, the motor 1 is accelerated from 0 to 2000 rotations/min in 8 seconds, and is spread to the center of the wafer at 2000 rotations/min. After b seconds, the resist is accelerated again to 4000 revolutions/min for (c-b) seconds, and resist is uniformly applied to the entire surface of the wafer until streaks are formed at the periphery of the wafer at 4000 revolutions/min for (d-c) seconds.

The rotation speed is lowered to 2000 revolutions/minute e seconds after the completion of coating, and after f seconds, the rotation speed is further lowered to 0 in (g−f) seconds. However, since a buffering and transmitting means was provided at this time, the sudden change in rotational speed at points a, b, C1... It is transmitted as a change, and the shock received from a sudden change in rotational speed is buffered. Therefore, there is no difference in rotational speed between the chuck 4 and the wafer W, and there is no contamination of the back surface of the wafer due to particles generated due to friction between the chuck and the wafer.

The resist coating device described above is one example, and the present invention is not limited thereto, and it goes without saying that it can be suitably used for a spin developer, spray etching, etc. of a developing device. be.

[Effects of the Invention] As is clear from the above explanation, the coating device of the present invention buffers the speed change of the motor and transmits it to the support base of the object to be coated, so that the rotational speed is maintained between the object to be coated and the support base. No deviation in rotation occurs due to sudden changes in rotation.

Therefore, there is no contamination of the back surface of the object to be coated due to the generation of particles due to friction between the object to be coated and the support, and a clean object to be processed can be manufactured.

[Brief explanation of the drawing]

Fig. 1 is an elliptical diagram of one embodiment of the coating device of the present invention, Fig. 2 is a sectional view of an open part, Figs. 3 and 4 are perspective views of the same part, and Fig. 5 is an explanatory diagram of one embodiment. It is. 3...Transmission means, 4...Chuck 5...Nozzle 6...Resist supply system (liquid supply system) w1+.
■Wafer

Claims (1)

[Claims] In a coating device that performs rotational coating by providing a workpiece on a support stand connected to a rotational drive mechanism, the support stand transfers the rotational speed of the rotational drive mechanism through a transmission means that buffers and transmits changes in the rotational speed of the rotational drive mechanism. A coating device characterized in that it is connected to a drive mechanism.