JP2806626B2 - Coating device - Google Patents

Description

The present invention relates to a coating device.

[Prior Art] Generally, in a process of forming a pattern on a thin film laminated on a semiconductor wafer in semiconductor manufacturing, a resist is applied to the semiconductor wafer, exposed and developed through a mask formed in the pattern, developed, etched, and thin film is etched. Are formed in a pattern shape. A resist coating device or a developing device used for resist coating or developing is configured to drop a certain amount of a resist solution or a developing solution stored in a storage container from a nozzle onto a semiconductor wafer which is vacuum-sucked on a chuck, and the chuck is moved. By rotating at a high speed, a resist or a developer dropped onto a semiconductor wafer is uniformly applied to the entire surface.

[Problems to be Solved by the Invention] However, with the ultra-high integration of integrated circuits,
Uneven coating has a significant effect. The coating unevenness may be largely caused by bubbles contained in the resist solution or the developing solution of the high clay, and the bubbles once mixed cannot be easily removed, and efforts are being made to remove the bubbles. In particular, as shown in FIG. 3, when the resist solution or the developing solution 2 is sent from the storage container 1 to the pipe 3 by sending a gas such as nitrogen gas under pressure from the pipe 4 to the storage container 1, the storage container 1 When the amount of the resist solution or the developing solution 2 remaining therein was reduced, bubbles were easily mixed. Therefore, a tank 5 is provided in the pipe 3 and a liquid amount in the tank 5 is measured by a liquid amount sensor 6.
Thus, the remaining amount of the resist solution or the developing solution in the storage container 1 is detected to prevent bubbles from flowing out to the nozzle.

However, when the residual amount decreases, the detection of air bubbles that would otherwise enter is not performed, and the coating film applied on the semiconductor wafer often becomes non-uniform. As a result, the yield of products has deteriorated.

The present invention has been made in order to solve the above-mentioned drawbacks, and it is possible to detect that a small amount of liquid remains in a container of a coating liquid supplied by pressure by gas and supplied to a pipe. Even if air bubbles are mixed in, air bubbles can be detected immediately,
An object of the present invention is to provide a coating apparatus that improves the yield of products.

[Means for Solving the Problems] To achieve the above object, a coating apparatus of the present invention is a coating apparatus that sends out the coating liquid from a pipe by pumping gas to a storage container storing the coating liquid. At least a part of the pipe has a transparent tube made of a transparent body, and has a sensor for detecting the presence of bubbles mixed in the application liquid sent from the storage container to the transparent tube. .

[Operation] At least a part of the piping of the coating apparatus for sending out the liquid to the outside of the storage container through the piping connected to the storage container by injecting the gas into the coating liquid stored in the storage container is a transparent tube. Form. A sensor such as a light emitting / receiving element is provided on the transparent tube. If bubbles of a certain size exist in the pipe, the amount of light incident on the light receiving element changes due to the bubbles, so that the presence or absence of the bubbles can be detected. When the bubbles are detected, it is possible to know that the remaining amount of the liquid in the storage container is small. Therefore, the liquid can be supplied to the storage container and a constant amount of liquid in which the bubbles are not always mixed can be supplied.

Embodiment An embodiment in which the coating apparatus of the present invention is applied to a resist coating apparatus in a semiconductor manufacturing process will be described with reference to the drawings.

The resist coating apparatus 7 shown in FIG. 1 has a disk-shaped chuck 10 on which a wafer 8 is mounted and fixed by vacuum suction or the like and which is fixed to a rotating shaft of a motor. A discharge nozzle 11 is provided above the chuck 10 so as to be connected to a horizontal moving mechanism, and can be retracted to a position outside the wafer 8 from above the chuck 10 to perform dummy dispensing. A cup 12 is provided around the chuck 10 so as to surround the chuck 10, and the resist dropped from the discharge nozzle 11 onto the wafer 8 is extended over the entire surface of the wafer 8. This prevents excess resist from scattering around. And a cup
Below the cup 12, in order to prevent the resist rebounded from the cup 12 from adhering again on the wafer 8, an exhaust port or the like connected to a not-shown exhaust device so as to form a gas flow toward the lower part of the cup 12 is provided. Provided. Further, the cup 12 is provided with a vertical movement mechanism (not shown) so as to be lowered from a position shown in the figure when loading and unloading the wafer 8 onto and from the chuck 10 by a transport mechanism (not shown) to facilitate loading and unloading of the wafer 8. Discharge nozzle
11 is a bellows driven by a suck-back valve 13 for sucking the remaining resist and an air cylinder 14 for sending out a certain amount of resist liquid, in order to prevent dripping of the resist remaining in the discharge nozzle 11 after resist dripping. The pump 15, the water jacket 17 for temperature adjustment for warming the pipe 16 to an appropriate temperature, the filter 20 connected to the deaerator 19 via the valve 18, the valve 21 and the liquid detector 22 Is connected to the storage container 24 for the resist solution 23. A nitrogen gas supply system 26, which is a gas, is connected to the resist solution container 24 via a pipe 25.

As shown in FIG. 2, a transparent tube 27 at least partially formed of a transparent body is inserted into the storage container 23 of the resist coating device 7 as described above. The liquid detecting device 22 provided in the transparent tube 27 includes a sensor 30 including a light projecting element 28 and a light receiving element 29. As shown in the figure, not only the transmissive type
The reflection type 8 and 29 may be provided in the same part. The light emitted from the light projecting element 28 changes the amount of light incident on the light receiving element 29 because the bubble 31 acts as a lens due to the presence of the bubble 31 mixed into the resist solution 23. The transparent pipe 27 has an inner diameter of 4 mm, for example.
If so, the bubbles 31 can be detected up to a diameter of 1 mm or less. The liquid detection device 22 further includes a CPU that outputs a detection signal when the sensor 30 detects the presence of the bubble 31 by comparing the input value from the light receiving element 29 with predetermined information, and outputs a warning sound generation signal from the CPU. A warning sound generating device 32 that sounds a warning sound is provided.

The operation of the resist coating apparatus 7 having the above configuration will be described.

The cup 12 is lowered from the position shown in the figure, and the wafer 8 is carried onto the chuck 10 by a transfer mechanism (not shown). cup
12 rises to the position shown in the figure and becomes ready for coating. The discharge nozzle 11 is moved to a position above the center of the wafer 8 by the horizontal moving mechanism to supply the resist liquid. A pipe 25 is inserted from the nitrogen gas supply system 26 into the storage container 24 for the resist solution 23,
Then, nitrogen gas is press-fitted into the storage container 24. Resist solution 23
Is pumped from the storage container 24 to the transparent tube 27. At this time, if the amount of the resist solution 23 is sufficiently secured in the storage container 24, the resist solution is sent out without bubbles 31 being mixed into the resist solution 23. Then, if the bubbles 31 are not detected by the sensor 30, the resist solution 23 continues to be sent to the transparent tube 27. Then, it is heated to an appropriate temperature by the water jacket 17 via the valve 21 and the filter 20, and is supplied to the bellows pump 15. In the filter 20, particles contained in the resist or bubbles not detected by the minute sensor 30 are filtered and removed by the deaerator 19. A predetermined amount of the resist solution 23 supplied to the bellows pump 15 is sent to the pipe 16 by the bellows pump 15 driven by the air cylinder 14, and is dropped from the discharge nozzle 11 onto the wafer 8 on the chuck 10. Thereafter, the discharge nozzle is operated by the suck back valve 13.
The resist liquid remaining without being dropped onto the liquid 11 is prevented from being sucked and dripped onto the wafer 8. Then, the chuck 10 is rotated at a high speed by the motor 9, and the resist is applied. After the coating, the cup 12 is lowered, the wafer 8 is loaded and unloaded, and the above steps are repeated. When the resist solution 23 in the storage container 24 is consumed and the remaining amount becomes small, the transparent tube 27
When a bubble 31 is generated therein, the amount of light incident on the light receiving element 21 that receives light emitted from the light projecting element 28 changes, and the sensor 30 sends a bubble detection signal to the CPU. The CPU outputs a warning sound generation signal to the warning sound generation device 32, and the warning sound is sounded. As a result, the operator can
When the user knows that the remaining amount is small, the valve 21 is closed and the container 24 is filled with the resist solution 23. Then, the valve 21 is opened, the air flowing into the pipe is removed by the deaerator 19 connected to the filter 20, and the resist coating is restarted. A color filter may be provided as appropriate for the photoelectric detection of the transparent tube 27 together with the detection of the bubble to provide a contrast.

According to the present invention, since air bubbles could not be detected conventionally, the operator had to visually check
The work efficiency can be greatly improved because it is known by the detection means, and it is also possible to eliminate the problem that the resist solution containing air bubbles is applied to the wafer to cause uneven application and a low yield.

The above description is an embodiment of the coating apparatus of the present invention,
The present invention is not limited to the resist coating apparatus, and can be applied to any apparatus using a coating liquid supplied from a storage container, for example, applying a developing liquid. It can be suitably used for those using a viscous liquid. Further, the present invention can be applied to an LCD substrate, a printed circuit board, and the like.

[Effects of the Invention] As is clear from the above description, according to the coating apparatus of the present invention, when the coating liquid in the storage container is supplied by pressurizing gas, bubbles mixed in the coating liquid are detected. To detect that the remaining amount is small and to provide a means for the operator to detect, so that air bubbles are prevented from being mixed into the coating liquid,
The liquid amount can be appropriately replenished as needed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment to which the coating apparatus of the present invention is applied, FIG. 2 is a diagram showing a main part of the embodiment shown in FIG. 1,
FIG. 3 shows a conventional example. 16 Piping 22 Liquid detecting device 23 Resist liquid (gas) 24 Storage container 26 Nitrogen gas supply system (gas) 27 Transparent tube 30 Sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B05C 7/00-21/00 H01L 21/30 G03F 7/16

Claims (1)

(57) [Claims] 1. A coating apparatus for sending out a coating liquid from a pipe by feeding gas to a storage container storing the coating liquid, wherein at least a part of the pipe includes a transparent tube formed of a transparent body, A coating apparatus, comprising: a sensor for detecting the presence of bubbles mixed in the coating liquid sent from the storage container to the transparent tube.