JPH02307566A - Coating apparatus - Google Patents

Abstract

PURPOSE:To permit coating to be applied in an outstandingly uniform film by controlling the temp. of a coating liq. according to at least either of temp. or humidity conditions in an environment of the coating operation by a rotary coater. CONSTITUTION:A resist 6 is dropped in a predetermined amt. from a nozzle 3 onto a wafer supported on a chuck 2 and rotatable at a high speed. At this time, the resist film thickness is small around the wafer and larger in its central part at a low environmental temp. and, at a higher environmental temp., it is small in the central part and larger around the wafer. Also, the resist film thickness is large at a low environmental humidity, and smaller at a higher environmental humidity. According to the relationship between the resist viscosity (temp.) and at least either of temp. or humidity conditions in a cap 11 previously fed by signals from CUP generated by outputs from a temp. sensor 12 and a humidity sensor 13, a temp. adjusting controller 14 energizes or deenergizes a heater 15 to increase or decrease the resist temp. to attain the optimum temp and thereby adjust an uneven resist film thickness produced in the central and peripheral parts of the wafer so as to make the resist film uniform in thickness.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a coating device.

[Prior art and problems to be solved by the invention] The following coating devices are available.

In order to obtain a desired pattern on a thin film during the wafer processing process for manufacturing semiconductor integrated circuits, a mask is created using a metal thin film or the like in the desired pattern on the thin film formed on the wafer, and a photosensitive film is applied on top of the mask. After applying resist, it is exposed and developed. In the coating process of applying this resist, it is necessary to form a uniform coating film in order to form a high quality semiconductor. Therefore, a spin coater uses a mechanism that supplies a certain amount of resist solution to drop resist from a nozzle installed on the wafer, and then applies the coating by rotating a chuck that holds the wafer in place by suction at high speed in a cup that surrounds the chuck. be.

It has been found that the thickness of the resist coating film is mutually influenced by the viscosity and temperature of the resist solution, the temperature of the wafer, and the surrounding environment such as temperature and humidity per revolution of the wafer. Therefore, the current state of the art is to control each of these parameters so that the conditions in the cup surrounding the wafer chuck are constant to ensure the accuracy of the film thickness.

However, the cost of temperature/humidity adjustment equipment for controlling constant conditions is high, and each parameter is interrelated, making it difficult to set optimal conditions.

The present invention was made in order to eliminate the above-mentioned drawbacks, and an object of the present invention is to provide a coating device that can coat a very uniform film.

[Means for Solving the Problems] In order to achieve the above object, the resist coating apparatus of the present invention is a spin coating apparatus that controls the temperature of the coating liquid by at least one of the temperature and humidity of the spin coating atmosphere. 6 [Function] The coating device of the present invention makes the film thickness uniform by controlling the temperature of the coating liquid, such as the temperature of the nozzle supplied from the nozzle, according to the ambient temperature and humidity during spin coating. . If the environmental temperature is high, the coating film, such as a resist film, will be thick at the periphery of the wafer and thin at the center, and if the environmental temperature is low, the resist will be difficult to stretch and will be thick at the center and thin at the periphery.

Furthermore, if the environmental humidity is optimal relative to the resist and wafer temperatures, a film with an optimal thickness can be produced. However, when the humidity is high, the film thickness becomes thin, and when the humidity is low, the film thickness becomes thick.

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

The resist coating device shown in FIG. 1 mounts and fixes a wafer W by vacuum suction or the like, and places the wafer W above the center of the disc of an upper disc-shaped chuck 2 fixed to the rotation shaft of a motor (rotary drive mechanism) 1. A discharge nozzle (nozzle) 3 is provided. If dispensing from the dispensing nozzle 3 is not performed for a predetermined period of time due to a break in the lot, etc., the resist liquid at the tip of the dispensing nozzle 3 may harden due to contact with air for a long period of time, so perform dummy dispensing. In order to retract the discharge nozzle 3 from above the chuck 2 to an outer position, it is movable by the scanner 4. A resist supply system 5, which is a resist supply device to which this discharge nozzle 3 is connected, includes a resist storage container 6.
A pump 8, such as a bellows pump, which supplies a desired constant amount of the resist 7 stored in the filter container 9 and the pump 8, a valve v1 that is opened and closed in conjunction with the filter container 9 and the pump 8, and a valve v1 that discharges the resist 6 from the discharge nozzle 3, and then discharges the resist from the discharge nozzle 3. It is comprised of a suckback valve 10 for pulling the resist back in and preventing dripping or assimilation of the resist.

Further, a cup 11 is provided surrounding the chuck 2 as a processing container to prevent the resist from scattering outside the apparatus during resist application. The cup 11 is movable up and down, and when the wafer W is loaded, it is lowered from the position shown in the figure to expose the chuck 8 and facilitate the loading ratio. 1 more cup
1 is provided with a temperature sensor 12 and a humidity sensor 13 for measuring the environment inside the cup 11, and a drain pipe, an exhaust pipe, etc. (not shown) are connected to the lower part of the cup 11.

Furthermore, the resist coating apparatus of the present invention includes a discharge nozzle 3.
A heater 15 serving as a temperature adjustment means is provided. CPU
It is believed that the temperature adjustment controller 14 controls the temperature of the coating liquid by operating the heater 15 in accordance with signals sent from the CPU based on input signals from the temperature sensor 12 and humidity sensor 13. The temperature adjustment means is not limited to a heater, but may be one in which the discharge nozzle 3 is made into a double pipe and a temperature adjustment water circulation path is provided around the resist passage path.

The resist viscosity can be changed by adjusting the resist temperature to tA by heating the temperature adjusting means (heater 15).

A method for forming a resist film having a uniform thickness using the resist coating apparatus configured as described above will be described.

When the wafer W is attracted and supported on the chuck 2 by a transport mechanism (not shown), the cup 11 rises as shown in FIG. For example, 1000 rotations/
sec, and then further, for example, 4000 rotations/s.
Rotate for a predetermined period with ee.

The resist supply system 5 is placed on the wafer W rotating at such a high speed.
A certain amount of resist 6 is dropped from the discharge nozzle 3 through the pipe. If the temperature inside the cup 11 at this time is lower than the optimum temperature for resist film formation, the dropped resist 6 will form a resist film 17 with a thicker film thickness at the center portion 18 of the wafer W, as shown in the cross-sectional view of FIG. is formed, but the temperature adjustment controller 14 operates the heater IS based on the relationship between the cyst viscosity (temperature) and at least one condition of the internal temperature and humidity of the cup 11, which are inputted in advance by a signal from the CPU based on the output of the temperature sensor 12. By increasing the resist temperature and adjusting the film thickness so that it is thinner in the center and thicker in the periphery, the non-uniformity of the film thickness that occurs between the center and the periphery can be offset, resulting in a film as shown in Figure 4. A resist film 17 having a uniform thickness can be obtained. Furthermore, if the temperature inside the cup 11 is higher than the optimum temperature for resist film formation, a resist film 17 with a thicker film thickness on the peripheral part 19 of the wafer W is formed as shown in FIG. By the controller 14,
The heater 15 is stopped, the resist temperature is lowered, and the resist film 1 is thicker in the center and thinner in the periphery, thereby canceling out the non-uniformity, resulting in a resist film 1 with a uniform thickness as shown in FIG.
Get 7. The same applies to humidity; the optimum humidity is, for example, 35%, and as the humidity increases, the resist film that is formed becomes thicker.
A change in 0A thickness occurs. The humidity inside cup 11 is also 30-4
Humidity sensor 1 changes around 0% and detects this change.
3 is detected, the temperature adjustment controller 14 operates the heater 15 by comparing the relationship between the humidity inside the cup 11 and the resist viscosity input in advance, and forms a resist film with a uniform thickness.

In the above embodiment, an example in which the present invention is applied to a resist coating apparatus has been described, but the present invention can be applied to any rotary coating, such as coating a developer or magnetic paint to a floppy disk, or manufacturing a magnetic tape.

[Effects of the Invention] As is clear from the above description, according to the coating apparatus of the present invention, uniform coating can be performed by controlling the temperature of the coating liquid.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the coating apparatus of the present invention, and FIGS. 2 to 4 are explanatory views of the resist coating apparatus shown in FIG. 1, respectively. 14...Temperature adjustment controller (means to control temperature)

Claims (1)

[Claims] A coating apparatus for spin coating, characterized in that the coating apparatus is provided with means for controlling the temperature of a coating liquid according to at least one of the temperature and humidity conditions of a spin coating atmosphere.