WO2001008814A1

WO2001008814A1 - Circular or annular coating film forming method

Info

Publication number: WO2001008814A1
Application number: PCT/JP2000/004789
Authority: WO
Inventors: Takuya Yokoyama
Original assignee: Chugai Ro Co., Ltd.
Priority date: 1999-07-29
Filing date: 2000-07-17
Publication date: 2001-02-08
Also published as: CA2379337A1; EP1205258A1; KR20020048376A; CN1365302A

Abstract

A method of forming a circular or annular coating film on a substrate (W) using a device of simple structure without using coating liquid wastefully, comprising the steps of, using a painting device (A) formed of a rotatable table (1) suckingly holding the substrate (W) horizontally and a horizontally movable nozzle (10) liftable relative to the table (1) and having a delivery hole (10a) at the tip part thereof, rotating the table (1) and supplying coating liquid from the delivery hole (10a) in a linear state on to the substrate (W) while moving the nozzle (10) by a specified interval between the rotating center of the table (1) and an outward specified position in one direction with the nozzle (10) held at a specified height relative to the rotating table (1) so as to form a circular or annular coating film on the substrate (W).

Description

Specification

Method of forming circular or annular coating film

Technical field

The present invention relates to a method for forming a circular or annular coating film on a substrate.

Background of the Invention

Conventionally, for example, a coating method using a spin coater has been known as a method for coating a substantially circular resist liquid on a substantially circular wafer. However, according to this method, the yield was very poor because most of the coating solution (about 95%) was discarded without being reused.

Also, as a coating method using a die coater, a shim (closing plate) is provided in the slit of the die body so as to be able to advance and retreat in the longitudinal direction of the slit. A method of horizontally moving a wafer (substrate) and applying a resist solution in a circular shape on the wafer has been proposed in Japanese Patent Application Laid-Open No. H10-99764.

In this method, it is necessary to hold the shim precisely and smoothly in the slit in order to prevent the coating liquid from leaking from between the shim and the slit. This not only required extremely high precision in the production and installation of shims and slits, but also required frequent shim changes due to severe wear. Further, in this method, the supply pressure in the width direction in the slit becomes non-uniform due to the movement of the shim, so that the coating S in the width direction cannot be formed uniformly. For this reason, in recent years, the slit length of the die body has been made almost the same as the radius of the wafer, one end of the slit is located at the center of the wafer, the other end is aligned with the edge of the wafer, and the wafer is It has been proposed that the coating liquid be applied by rotating the coating liquid without waste. However, this method has a problem in that an overlapped portion of the slit is formed at the center of the wafer, so that the coating film thickness in this portion becomes large, and a uniform coating film thickness cannot be formed.

In addition, there is a problem that an annular coating film cannot be formed by the above-described coating method. Summary of the Invention

The present invention has been made for the purpose of eliminating the above-described problems, and has a simple configuration of a circular or annular coating film capable of making the film thickness uniform without wasting the coating solution. The present invention provides a forming method.

In order to achieve the above object, the present invention provides a rotatable table for horizontally sucking and holding a substrate, a vertically movable table which can be moved up and down with respect to the table, and a horizontally movable table having a discharge hole at a tip end. The table is rotated using a coating device including a nozzle, and the center of rotation of the table and a predetermined outside position are held while the nozzle is held at a predetermined height with respect to the rotating table. The coating liquid is supplied onto the substrate in a linear state from the discharge hole while moving a predetermined section between the two in one direction. ADVANTAGE OF THE INVENTION According to this invention, a circular or annular coating film can be formed simply by moving a nozzle linearly with respect to a rotating substrate, without providing a complicated mechanism in the coating apparatus, regardless of the shape of the substrate. . Moreover, according to the present invention, there is an effect that there is almost no waste of the coating liquid.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view of a coating apparatus used in the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG.

FIG. 3 is a diagram viewed from the direction of the line 方向 Ι Ι においてにおいて in FIG.

FIG. 4 is a side view showing the movement of the nozzle of the coating apparatus.

Detailed Description of the Preferred Embodiment

Next, an embodiment of the present invention will be described with reference to the drawings.

The figure shows a coating apparatus A for carrying out the present invention.

The coating device A generally includes a table 1 and a nozzle 10 as shown in FIG. As shown in FIG. 2, the table 1 is fixed to one end of a hollow shaft 4 provided through a base 6, and the hollow shaft 4 is provided via a bearing 5 provided in a through portion of the base 6. It is held rotatable together with 4. The other end of the hollow shaft 4 is connected to a vacuum pump (not shown) via a single joint 7. A gear 8 is provided at a protruding portion of the hollow shaft 4 on the lower surface side of the base 6, and a gear 9 meshing with the gear 8 is By driving in Ichita M _I, the table 1 is rotated.

The surface of the table 1 has a predetermined flatness, for example, a flatness of 2 μm or less. Inside the table 1, headers 2 communicating with the space 4a of the hollow shaft 4 are radially provided, and a number of suction holes 3 penetrating from each header 2 to the surface of the table 1 are provided. ing. Therefore, by driving the vacuum pump, the substrate W can be suction-held on the surface of the table 1 to correct the warp or undulation of the substrate W.

As shown in FIGS. 1 and 2, on the two rails R disposed opposite to each other in the width direction of the base 6 with the tape 1 interposed therebetween, the rail 6 is moved forward and backward by a horizontal moving mechanism. A stand 11 to be mounted is placed. Furthermore, the On the platform 1 1 with beam 1 4 the both side portions are supported is provided through the lifting mechanism 1 3 consisting Sutetsupi Ngumota M ₂ and non-backlash of the ball screw 1 2 which in the lifting mechanism 1 3 I have. Then, the nozzle 10 is held at a predetermined position of the beam 14, that is, at a position where the discharge hole 10 a of the nozzle 10 passes through the rotation center of the table 1 when the gantry 11 advances and retreats. .

As a result, the discharge hole 10a of the nozzle 10 can move in one direction between the center of rotation of the table 1 and a predetermined outside position while maintaining a predetermined height from the surface of the table 1. Become.

In addition, as shown in FIG. 3, the discharge hole 10a of the nozzle 10 is formed so as to supply the coating liquid linearly to the substrate W suction-held on the table 1. I have.

Next, a method of using the coating apparatus A having the above configuration will be described.

First, the gantry 11 is moved by a horizontal moving mechanism (not shown) to position the nozzle 10 at one end of the base 6 as shown in FIG. After that, for example, the substrate W made of a wafer is placed on the table 1, and the vacuum pump is driven to suction-hold the substrate W on the table 1.

Further, while the table 1 is rotated by driving the motor M, the gantry 11 is moved by the horizontal moving mechanism, and the discharge holes of the nozzle 10 are moved as shown by phantom lines in FIG. Position 10 a above the center of rotation of table 1.

Subsequently, the stepping motors M ₂ and M ₂ are driven to lower the nozzle 10 and

The distance between the tip of the nozzle 10 and the surface of the table 1 is adjusted so as to be a predetermined distance (reference gap).

Thereafter, a coating liquid supply device (not shown) is driven to supply the coating liquid to the nozzles 10 to start the coating, and the base 11 (the nozzles 10) is placed on the substrate W as shown in FIG. Move to a predetermined outside position.

In this case, nozzle 10 basically turns nozzle 1 while table 1 makes one revolution.

Moves by the same distance (the width dimension of the discharged coating liquid) as the width of the 0 discharge hole 10a. However, depending on the properties of the coating liquid, the width of the discharge hole 10a (the width of the discharged coating liquid)

) You may move the above distance.

Focusing on the leveling properties of the coating liquid, for example, when applying a coating liquid with poor leveling properties, the coating liquid is unlikely to spread on the substrate surface. If 10 is moved by the same distance as the width of the discharge port 10a so that the side of the linear coating liquid supplied from the discharge port 10a contacts the side of the coating film formed by the previous rotation. good. On the other hand, when applying a coating liquid with a good leveling property, the coating liquid easily spreads on the substrate surface. Then, a gap may be formed between the side surface of the coating film formed by the previous rotation and the side surface of the linear coating liquid supplied from the discharge hole 10a.

The leveling property of the coating liquid means the fluidity of the coating liquid itself. Therefore, if the leveling property of the coating solution is good, the coating is applied to the substrate, and after a predetermined period of time, the formed coating film is uniformly diffused to the substrate surface by the fluidity of the coating solution itself, and A good coating state without dirt and unevenness is obtained. For this reason, in general, the lower the viscosity of the coating liquid, the higher the leveling property. Even if the viscosity of the coating solution is low, for example, when a coating solution using a highly volatile solvent is applied, the coating film is uniformly diffused to the substrate surface due to the fluidity of the coating solution itself. Before the solvent evaporates and dries, streaks and unevenness may occur. Such coating liquids have good leveling even if the viscosity is low. Absent.

In other words, since the substrate W is rotating, the linear coating liquid flowing down from the discharge holes 10a flows down along the grooves on the record surface, and the centrifugal force and the coating liquid based on the rotation of the substrate W Due to this leveling property, a circular coating film having a uniform thickness is formed on the substrate W.

Then, when the nozzle 10 is horizontally moved by the radius of the desired circular coating film, the supply of the coating liquid is stopped and the rotation of the table 1 is stopped. After that, the stepping motors M ₂ and M ₂ are rotated to raise the nozzle 10 to a predetermined position, and the horizontal movement mechanism is driven to move the nozzle 10 to the predetermined position on the base 6 for the next step. Wait (see Figure 1).

When the circular coating film is formed on the substrate W as described above, the vacuum pump is stopped, and the substrate W is transferred to the next step by means not shown. Then, the next substrate W is placed on the table 1, and the coating step is repeated again.

In the above description, the substrate W is a circular wafer, but the substrate W is not limited to a wafer, and the shape of the substrate is not limited to a circle. Further, the cross-sectional shape of the discharge hole 10a may be any of a circular shape and a rectangular shape.

In the above description, the nozzle 10 is moved linearly from the center of rotation of the table 1 toward the outside of the substrate W. Conversely, the nozzle 10 may be moved from a predetermined position outside the substrate W toward the center of rotation. good.

In the coating step, as the position of the nozzle 10 moves outward from the center of the table 1 and a certain level moves from the outside to the center, the peripheral speed of the substrate W below the ejection hole 10a changes. Therefore, the supply amount of the coating liquid may be gradually increased or decreased in accordance with the change in the peripheral speed. Further, the peripheral speed at the application position may be kept constant by changing the rotation speed of the table 1.

By the way, in the above description, the shape of the coating film is circular. However, by supplying a coating liquid in a linear state from the discharge holes onto the substrate while moving a predetermined section between the rotation center of the table and a predetermined outer position in one direction, the annular coating film is formed. Can be formed. Furthermore, an annular coating film is formed on the same substrate at arbitrary intervals. Thus, a stripe-shaped coating film can be formed.

Example

As a result of applying the method according to the present invention under the following conditions, a favorable coating film having a thickness of Ομπι was formed.

(1) Substrate

Diameter: 20 Omm

Rotation speed: 60 rpm

(2) Nozzle

Inner diameter: 1.0 mm

Travel speed: 1.0 mm / sec

Moving direction: direction toward the center of the substrate

Moving range: From the position of the substrate diameter of 192 mm to the center of the substrate (diameter Omm) Gap: 60μηι (distance between the substrate and the nozzle tip)

Discharge rate: 100% at coating start position

0% at the end of dispensing

(3) Coating liquid

Viscosity: 10 p (l O O O c p)

Claims

The scope of the claims

1. A rotatable table that horizontally holds and holds a substrate, and a horizontally movable nozzle that can move up and down the table and has a discharge hole at the tip. Using a device, the table is rotated, and a predetermined section between the center of rotation of the table and a predetermined outside position is held in a state where the nozzle is held at a predetermined height with respect to the rotating table. A method for forming a circular coating film, wherein the coating liquid is supplied onto the substrate in a linear state from the discharge hole while being moved in one direction.