JPH08266996A - Rotary coating method - Google Patents

Abstract

PURPOSE: To eliminate coating irregularity or inferiority and to enhance film thickness uniformity by individually controlling respective surface temps. measured by dividing the surfaces of a stage and a rotary stage in a matrix state and controlling the temp. of a dripping resist soln. and air in a spin cup. CONSTITUTION: The surfaces of a stage 1 and a rotary stage 10 are divided into respective matrix sections and the surface temps. of the respective sections are measured to individually control the respective sections by a control part to uniformize the surface temps., for example, to 25 deg.C. A substrate 9 to be coated is once placed on the substrate stage 1 and the surface temp. thereof is uniformized to 25 deg.C and this substrate 9 is placed and fixed on the rotary stage 10 of which the surface temp. is uniformized to 25 deg.C within a rotary coating apparatus. Subsequently, a necessary amt. of a resist 13 of which the temp. is regulated to 25 deg.C is dripped on the substrate 9 to be coated from a nozzle 12 and, after a lid 14 is allowed to fall to cover the rotary stage 10, the rotary stage 10 is rotated at a predetermined speed. At this time, air of which the temp. is regulated to 23 deg.C is supplied into a spin cup 11 to be discharged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating method for forming a coating film of a photosensitive resin or the like on the surface of a plate-shaped substrate such as a glass plate for a color filter.

[0002]

2. Description of the Related Art Of the methods for coating a photosensitive colored resist in the manufacturing process of color filters for liquid crystal display devices, the spin coating method is widely used. That is, by fixing the substrate to be coated on the rotating stage, dropping the resist onto the substrate, and then rotating the rotating stage on which the substrate to be coated is rotated together with the spin cup covering the rotating stage on which the substrate to be coated is placed, It is a coating method of spreading the resist dropped onto the surface of the substrate to be coated. In the spin coating method, it has been generally known that the uniformity of the coating film thickness, that is, the variation of the coating film thickness on the same substrate is about 5%. However, due to the temperature difference between the substrate, each part of the apparatus used in the spin coating method, the resist, the ambient temperature, etc., the viscosity coefficient of the resist on the substrate varies from part to part. Therefore, the coating thickness uniformity is 5%
Even within the range, for example, when the average coating film thickness is 1.2 μm, the unevenness in the coating film thickness is visually recognized as the coating unevenness due to the steep variation in the coating film thickness such that the region with the film thickness of 1.18 μm and the region with the film thickness of 1.23 μm are close to each other. Defects often occurred.

For this problem, although the temperature control of the resist to be coated, the temperature control of the substrate to be coated by heating and cooling, etc. have already been individually carried out, a comprehensive temperature control is necessary. It has not been. For this reason, like a photosensitive resist, especially a colored resist, thixotropy (so-called thixotropic property), that is, the internal bond of the gel is partially or completely destroyed by an external force to be changed to a fluid sol, and when it is left as it is, the interparticles are regenerated. In the spin coating method using a coating liquid having a property that the bond of is reproduced and becomes a gel, a minute temperature difference occurs between the coating liquid and the substrate to be coated, which causes uneven film thickness. Was there.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a coating method which eliminates the above-mentioned defective coating unevenness and improves the film thickness uniformity.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a stage for receiving a plate-shaped substrate from a substrate transfer unit and mounting the substrate thereon, a rotary stage for mounting and fixing the substrate transferred from the stage, and a nozzle. The rotating stage is rotated by using a spin coater including a resist supply unit that drops the resist onto the substrate on the rotating stage, and a spin cup that covers the rotating stage when the rotating stage rotates and rotates together with the rotating stage. In the spin coating method in which the resist dropped on the substrate is spread on the substrate surface with a uniform film thickness, the stage and the rotary stage surface are each divided into matrix-shaped sections, and a means for measuring the surface temperature of each section is provided. A means for controlling the surface temperature of each section separately and a means for controlling the temperature of the resist solution dropped from the nozzle. When a spin coating method characterized by comprising a means for evacuating the spin cup air while supplying the desired temperature of the air in the spin cup.

Further, the present invention is a spin coating method characterized in that the above spin coating apparatus is covered with a thermal chamber, and means for controlling the ambient temperature in the thermal chamber is provided. Further, the present invention is the spin coating method, characterized in that the matrix-shaped sections on the surface of the stage and the rotary stage are set to 3 × 3 or more.

That is, the inventors of the present invention have made intensive studies in view of the above problems, and have taken countermeasures against the following four elements to make a spin coating method in which the temperature is adjusted with respect to the substrate, coating solution, and ambient temperature. Is proposed. <1> Temperature Control of Substrate Contact Portion As shown in FIGS. 1 and 2, the surface of the substrate stage 1 is divided into a plurality of sections, for example, in a matrix. The stage surface temperature is measured for each of the divided sections. As the temperature measuring means, for example, a thermistor 2 may be provided for each section, or thermography may be used to measure the temperature of each section. Next, as shown in FIG. 1, each surface temperature data measured by the temperature measuring means is sent to the controller. Next, when there is a difference in the received temperature data of each surface, the control unit issues a temperature adjustment command to each section in order to make each surface temperature uniform. In the example of FIG. 1, a command for the cooling pipe is issued in the case of cooling, and a command for the heater is issued in the case of heating. Here, as shown in the example of FIG. 2, a heater 4 and a cooling pipe 5 provided for each section
Is operated based on the respective instructions received, so that the temperature of each section surface is controlled to be constant. As a result, variations in the temperature of the surface of the substrate stage 1 are eliminated, and variations in the surface temperature of the substrate placed on the substrate stage 1 are eliminated. If necessary, the glass substrate holding vacuum chuck of the rotary stage 10 in the spin cup is equipped with the same temperature measuring means and control means as described above.

<2> As means for adjusting the temperature of the resist 13 liquid dropped from the resist nozzle 12 onto the substrate, for example, as shown in FIG. 3, the resist tank 6 and the conduit in which the internal temperature is adjusted to a desired temperature are provided. The resist 13 has a structure in which the resist 13 constantly returns to maintain the resist 13 at a desired temperature. Next, when the resist 13 is applied, a necessary amount of the resist 13 is diverted from the switching valve 7 and drawn into the nozzle 12. Resist here 1
In order to prevent the temperature change when 3 passes through the inside of the nozzle 12, the nozzle 12 is covered with a temperature control jacket, which allows the resist 13 solution to be dripped onto the substrate at a desired temperature.

<3> Inside coating apparatus As shown in FIG. 4, the temperature of the structure in which the air inside the spin cup 11 is exhausted while the air whose temperature is adjusted to a desired temperature is supplied into the spin cup 11 that covers the rotary stage 10. A control means is provided. <4> Thermal Chamber As shown in FIG. 4, by covering the entire spin coating apparatus with a temperature-controlled thermal chamber 8, the atmospheric temperature in the chamber is controlled to be constant. Above <3> and <4>
In order to supplement the control of the ambient temperature inside and around the spin coating apparatus, which cannot be made constant only by adjusting the temperature in the clean room where the spin coating apparatus is placed, two more stages are added to strictly control.

[0010]

By the comprehensive temperature control of <1> to <4> described above, the temperature of the substrate surface can be set to a desired temperature on the entire surface without variation due to the site, and the temperature of the resist solution is always desired. Kept at temperature. As a result, the temperature difference between the substrate surface and the resist solution during coating is eliminated, so that the coating film thickness is made uniform and the occurrence of coating unevenness is eliminated.

[0011]

Embodiments of the present invention will be described with reference to the drawings. In the step of applying and forming a photosensitive resin or the like on the surface of a plate-shaped substrate such as a glass plate for a color filter, first,
As shown in FIG. 4, it is temporarily placed on the substrate stage 1. At this time, the substrate stage 1 has its surface divided into 4 × 4 matrix-shaped sections as shown in FIG.
The thermistor 2 is arranged on the surface, and the surface temperature of each section is measured by the probe 3 at the center thereof. The temperature data of each section measured here is transmitted to the control section as shown in FIG. 1, and the section is arranged directly under the thermistor 2 shown in FIG. The heater 4 and the cooling pipe 5 installed for each of them were operated to individually heat or cool the surface of each compartment. As a result, the surface temperature of the substrate stage 1 is made uniform to 25 ° C., and the surface temperature of the substrate 9 to be coated on the substrate stage 1 is also 25 ° C.
Homogenized to ° C.

Next, the substrate 9 to be coated conveyed from the substrate stage 1 is placed and fixed on the rotary stage 10 in the rotary coating apparatus as shown in FIG. Here, the vacuum chuck for holding the substrate of the rotary stage 10 is also equipped with the same temperature control means as the above-mentioned substrate stage 1, so that the substrate temperature is made uniform.

Next, the resist 13 supply means as shown in FIG. 3, that is, the resist tank 6 whose temperature is adjusted to 25.degree.
A resist 13 is supplied from a resist temperature control system having a structure in which the resist 13 circulates in the conduit and a structure in which a necessary amount of the resist 13 is diverted from the switching valve 7 and drawn into the nozzle 12 when the resist 13 is applied, for example, Fuji Hunt. Pigment dispersion photoresist, trade name "CR-2"
000 ”was dropped on the surface of the substrate 9 to be coated on the rotary stage 10 as shown in FIG.

Next, the lid 15 descends and the spin cup 11
After covering the rotary stage 10 by being integrated with the spin cup 11, the spin cup 11 rotates together with the rotary stage 10 and the substrate 9 to be coated under the condition of 800 rpm for 10 seconds. By this rotation, the resist 13 dropped on the substrate 9 to be coated was coated on the surface of the substrate 9 to be coated with a uniform film thickness.

As shown in FIG. 4, temperature control means having a structure for exhausting the air in the spin cup 11 while supplying the air whose temperature is adjusted to 23 ° C. to the spin cup 11 of the coater is provided. The entire spin coater is covered with a thermal chamber 8 and the ambient temperature inside the chamber is controlled to 23 ° C.

[0016]

EFFECTS OF THE INVENTION By the comprehensive temperature control according to the present invention, the coating film thickness is made uniform, and the problem of coating unevenness is solved. Further, according to the configuration of the present invention, it is possible to easily cope with a large-sized color filter substrate and it is effective. Also,
Cooling after prebaking can be expected to improve throughput because the cooling time can be shortened as compared with cooling by natural heat dissipation by utilizing the positive temperature control of the present invention.

[0017]

[Brief description of drawings]

FIG. 1 is an explanatory plan view showing an embodiment of a substrate temperature control system which constitutes a main part of the present invention.

FIG. 2 is a perspective explanatory view showing an embodiment of a substrate temperature control unit which constitutes a main part of the present invention.

FIG. 3 is an explanatory diagram showing an embodiment of a resist supply system that constitutes the present invention.

FIG. 4 is an explanatory diagram showing each element of the temperature control measure that constitutes the present invention.

[Explanation of symbols]

 1 substrate stage 2 thermistor 3 probe 4 heater 5 cooling pipe 6 resist tank 7 switching valve 8 thermal chamber 9 substrate to be coated 10 rotating stage 11 spin cup 12 nozzle 13 resist 14 lid 15 conduit

Claims (3)

[Claims] 1. A stage for receiving a plate-shaped substrate from a substrate transfer means and mounting the substrate thereon, a rotary stage for mounting and fixing the substrate transferred from the stage, and a substrate on the rotary stage from a nozzle. Using a spin coater consisting of a resist supply means for dropping the resist and a spin cup that covers the rotary stage when the rotary stage rotates and rotates with the rotary stage, the rotary stage is rotated to drop the resist on the substrate. In a spin coating method of spreading a resist on a substrate surface with a uniform film thickness, the stage and the rotary stage surface are each divided into matrix-shaped sections, and means for measuring the surface temperature of each section and the surface temperature of each section are Means for controlling separately, means for controlling the temperature of the resist solution dropped from the nozzle, and the inside of the spin cup. Spin coating method characterized by comprising a means for evacuating the spin cup air while supplying the temperature of the air Nozomu. 2. The spin coating method according to claim 1, further comprising means for covering the spin coating device with a thermal chamber and controlling the atmospheric temperature in the thermal chamber. 3. The spin coating method according to claim 1, wherein the matrix-like divisions on the surface of the stage and the rotary stage are 3 × 3 or more.