JPS6317527A - Applying method of resist - Google Patents

Abstract

PURPOSE:To decrease dust and resist spots by conducting application at at least one time and bringing the inside of an oven body to open space during the period of application up to the completion of revolution at high speed determining the final film thickness of a resist and discharging a solvent mist. CONSTITUTION:Mask blanks 5 are placed and sucked to a spin chuck 4 while a closing cover 6 and the side-wall upper section of an applying oven body 1 are fast stuck, and the inside of the applying oven body is brought completely to a closed state. A resist is dropped to the center of the mask blanks 5 by a resist nozzle 7, dropping is finished while the spin chuck 4 is turned for a fixed time by revolution at low speed, rotational speed is increased up to normal revolution, high-speed spin coating is performed by the number of revolution for a specified time, and application is completed. The closing cover 6 is lifted and the applying oven body 1 is opened for the time up to the number of revolution at high speed determining predetermined final film thickness at that time, and a ventilating-fan 3 is operated and the mists of a solvent dissolving the resist are removed. Accordingly, dust and resist spots can be decreased, while maintaining resist film thickness uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Industrial Field of Application) The present invention relates to a resist coating method, and particularly to a method of coating a high molecular weight, high viscosity resist on a semiconductor substrate.

(Prior Art) Conventionally, resist coating has been carried out by dropping the resist in an open space while uniformly evacuation, and then applying and drying the resist while controlling the film thickness by constant rotation or multi-stage rotation.

However, with polymeric, high-viscosity resists such as resists for electron beam exposure, the state of resist application may fluctuate due to conditions such as: (1) rising acceleration immediately after dropping the resist, (2) exhaust during spin coating, and environmental concentration. know. For example, if the spin motor does not have a sufficiently large acceleration for the start-up of (■), or if the exhaust of (■) is too strong and the resist solvent dries quickly, traces of dripping may remain as they are as changes in film thickness. The resist scattered during the spin code dries and becomes thread-like, and the thread-like resist often gets on the substrate during coating rotation or when the rotation is stopped, resulting in poor coating.

By the way, to solve this problem, it is possible to increase the acceleration to high speed rotation using an effective spin motor, use the square acceleration method, etc., temporarily stop the exhaust inside the coating pot at the start of rotation, or The control of displacement has been improved over time. However, sufficient effects have not been achieved.

In addition, recently, the inventors of the present invention have investigated a sealed coating method for the above-mentioned countermeasures, and it has been confirmed that it is effective, but dust and resist spots were observed throughout the substrate surface inspection after coating. It has been found that about 10% of the cases exist, and improvement is required.

(Problems to be Solved by R-Mei) The present invention was made in view of the above circumstances, and is a resist coating that can reduce dust and resist spots while preventing coating unevenness and maintaining a uniform resist film thickness. The purpose is to provide a method.

[Structure of the Invention (Means and Effects for Solving the Problems)] The present invention provides that the coating pot body is heated at least once during the coating period until the end of high-speed rotation, which determines the final film thickness of the resist, and a solvent is removed. It is characterized by exhausting the mist, thereby reducing dust and resist spots and making it possible to obtain a resist film with a uniform thickness.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2. Here, FIG. 1 is a schematic sectional view of a resist coating apparatus according to the present invention, and FIG. 2 is a characteristic diagram of the coating rotation speed during sealed coating.

1 in the figure is the coating pot body. The side wall and bottom of the applicator pot body 1 form a cavity 2, and the cavity 2 communicates with an exhaust fan 3. A spin chuck 4 rotatable, for example, in the six directions of arrows is provided approximately at the center of the coating pot body 1. On this spin chuck 4,
A mask blank 5 as an object to be processed is attracted. A removable sealing lid 6 is provided at the top of the coating pot body 1 so as to close the cavity 2 of the side wall.
A resist nozzle 7 is attached approximately at the center of the image forming apparatus.

The operation of the resist coating apparatus having such a structure is as follows. First, the mask blank 5 is placed on the spin chuck 4 and adsorbed, and the sealing lid 6 and the upper side wall of the coating pot main body 1 are brought into close contact with each other to completely seal the interior of the coating pot main body. Next, from the resist nozzle 7, the mask blank 5 is
Drop resist in the center. At the same time as this dripping is completed, Or, p, a is rotated at low speed, for example, 0.5 seconds after starting.
From 200 r, p, m, after performing fmdo rotation for 3 seconds at 20 or, p, m, increase to normal rotation of 400 r, plw at the start of 0.5 seconds, and high speed at this rotation speed for 20 seconds. Perform spin coating to complete the coating (see Figure 2). At this time, the sealing 11
6 was raised to open the coating pot body 1, and the exhaust fan 3 was operated to remove the solvent mist that was dissolving the resist.

According to the above embodiment, the solvent mist is exhausted by the exhaust fan 3 within the coating pot body 1 for about 4 seconds until the high rotation speed that determines the final film thickness of the resist.
Compared to conventional methods, it is possible to reduce the amount of paint dust and resist spots. fact,
The incidence of coating defects, which are mainly caused by dust and resist spots, has been reduced from about 10% (previously) to less than 1%.
A significant improvement in coating was achieved. Furthermore, the uniformity of the coating film thickness, which is an advantage of the original sealed coating, can be maintained.

In the above embodiment, the solvent mist was exhausted once during the resist coating rotation as shown in FIG. 2, but the present invention is not limited to this. For example, as shown in FIG. 3, the spin chuck rotation speed during coating increases rapidly, causing a large amount of resist to scatter from the mask blank, and creating a solvent mist. 1 every .5 to 5.0 seconds
Even if the exhaust is performed twice in total, the same effect as in the above embodiment can be obtained.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to provide a highly reliable resist coating method capable of reducing dust and resist spots while maintaining a uniform resist film thickness.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic cross-sectional view of a resist coating device according to the present invention;
FIGS. 2 and 3 respectively show characteristic diagrams of the coating rotation speed during sealed coating according to the present invention. DESCRIPTION OF SYMBOLS 1... Coating pot body, 2... Cavity part, 3... Exhaust fan, 4... Spin chuck, 5... Mask blanks (object to be processed), 6... Airtight lid, 7... ...Resist Nozzle O Applicant Representative Patent Attorney Takehiko Suzue Figure 1

Claims (1)

[Claims] In a resist coating method that uses a resist coating device to coat a resist onto an object to be treated, at least
A resist coating method characterized by creating an open space within the multi-coating pot body and exhausting solvent mist.