JPH029476A - Spin coating device - Google Patents

Abstract

PURPOSE:To reduce significantly the amount of mist particles sent flying to a material to be treated by installing a slant section and a receiving section near a position where a liquid coating agent which is caused to fly in mist particles by rotation of the material to be treated at high speed and a cup collide, when a uniform regist film is formed on the surface of a semi-conductor wafer. CONSTITUTION:When a liquid coating agent is supplied and the surface of a material to be treated 11 which rotates at high speed between an upper cup 16 and a lower cup 17 is spin-coated, the liquid coating agent is sent flying in mist particles inside the cup by rotation of the material to be treated 11 at high speed. In this case, the inclined angle near a position where the flying particles collide with the inner part of the upper cup 16 is adequately obtuse downward with the surface of the material to be treated 11. In addition, a receiving section 16c is provided at a position following a slant section 16b so that the mist particles of the coating agent which generate through collision with the slant section 16b are allowed to fall and gather together in the receiving section 16c. Consequently, even the small amount of mist particles generated is almost not scattered over the material to be treated 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a spin coating apparatus used for applying a liquid coating agent such as a resist to the surface of a workpiece.

(Prior Art) A spin coating apparatus is used to coat the surface of a workpiece such as a semiconductor wafer with a liquid coating agent in a uniform thickness in the manufacturing process of electronic components such as semiconductor devices manufactured using precision photography technology. By P! Xl811 is used, for example, to form a resist film.

FIG. 4 is a diagram showing an example of the configuration of a conventional spin coating device used for forming a resist film in the manufacturing process of such electronic components, etc., in which a workpiece such as a semiconductor wafer is vacuum chucked. The processing table 2 held by the above-mentioned apparatus is connected to a rotation mechanism (not shown) that rotates the processing object 1 together with the processing table 2 at high speed.

A discharge nozzle 3 connected to a resist liquid supply mechanism (not shown) is arranged above the approximately central portion of the workpiece 1, and a predetermined amount of resist is applied from the discharge nozzle 3 onto the workpiece L. liquid is supplied.

The object to be processed 1 is surrounded by an upper cup 4 and a lower cup 5, and the upper cup 4 has a cylindrical shape in which an upper opening 4a has a smaller diameter than a lower opening 4b. , is fitted into the lower cup 5.

The lower cup 5 is connected to an inner cup part 6 which is inclined outwardly and downwardly from the lower part of the object to be processed 1, and a drain pipe 8, and has a drain part whose bottom part is slightly inclined at 7 toward the drain pipe 8 side. The outer cup part 7 has a liquid groove 78.

Furthermore, an exhaust pipe 9 is provided in the lower cup 5 to prevent the resist liquid from scattering to the outside and to prevent harmful effects caused by splashes. It will be done.

In a spin coating apparatus with such a configuration,
The workpiece 1 is suctioned and held on the mounting table 2 by a vacuum chuck or the like, and the workpiece 1 is rotated together with the ag1 stand 2 at a rotational speed of, for example, about 3000 r, p, 1 around the center of the workpiece 1. A resist solution is supplied to the surface, and unnecessary resist solution is removed by rotational force to form a thin and uniform resist film over the entire surface of the object to be processed 1.

(Issue 8 to be solved by the invention) However, in the conventional spin coating apparatus as described above, since the workpiece 1 such as a semiconductor wafer is rotated at high speed, the liquid coating agent scattered from the workpiece 1 is For example, when the resist liquid is flying or collides with the sloped surface of the inner wall of the upper cup 4, it splits into particles, that is, mist particles. These mist particles reach the drain groove 7a either directly or while colliding again with the inner cup portion 6, etc., and are discharged to the outside from the drain pipe 8, but the diameter of the mist particles formed by these collisions is small. Because of this, some of it flies upward and adheres to the surface of the workpiece, causing defects. This is because although the inside of the cup is exhausted through the exhaust pipe 9, turbulence occurs inside the cup due to the rotation of the object 1, etc., and an upward airflow is generated in the opposite direction to the exhaust flow. This is because the mist particles descend directly towards the target. As a countermeasure for this, Japanese Patent Application Laid-Open Nos. 52-128172, 54-9919, 57-130422, 5g-104669, 59-33453, 60-139364, 80-143872, 61 -46028, same 6
No. 1-291072, No. 62-1474, Special Publication No. 1983
-27229, Special Publication No. 80-29549, 82-
No. 49728, Utility Model Application Publication No. 55-147043, etc.

In addition, some of the mist particles generated by collision with the inner wall of the upper cup 4 bounce directly toward the object to be treated, which is also a cause of adhesion of the mist particles.

In order to solve this problem, increasing the exhaust volume may be considered.In this case, although the number of mist particles adhering to the surface of the workpiece will be reduced, increasing the exhaust volume will reduce the number of mist particles that adhere to the surface of the workpiece. A problem arises in that the uniformity of the coating film formed on the surface of the object by the liquid coating agent deteriorates.

The present invention was made in order to address the problems of the prior art, and it is possible to avoid deterioration of the uniformity of the coating film caused by the liquid coating agent formed on the surface of the workpiece, and to improve the rotation of the workpiece. At the same time, it suppresses the flight of mist particles that are generated when the liquid coating agent collides with the inner wall of the cup toward the object to be treated,
It is an object of the present invention to provide a spin coating device in which the adverse effects of these mist particles are significantly reduced.

[Structure of the Invention] (Means for Solving the Three Problems) That is, the present invention provides a liquid coating agent that is generated and scattered by supplying a liquid coating agent to the surface of an object to be treated and spinning the coating on the object to be treated. In a spin coating apparatus in which the liquid coating agent is received by a cup, an oblique part is provided near a collision position of the liquid coating agent that is scattered as the workpiece rotates in the cup, and the liquid coating material after colliding with the oblique part is It is characterized in that a receiving part for the coating agent is provided in the IIJ cup.

(Function) In the spin coating apparatus of the present invention, the liquid coating agent that scatters as the object to be treated rotates first collides with the oblique portion inside the cup. Here, for example, if the angle between the oblique portion and the surface of the object to be treated is made sufficiently obtuse, most of the mist particles of the liquid coating agent generated by colliding with the oblique portion will be collected in the receiving portion. After a liquid pool is once formed by this receiving portion, the waste liquid of the liquid coating agent is discharged to the outside. Therefore, the mist of the liquid coating agent that flies toward the object to be treated due to the upward airflow generated inside the cup can be significantly reduced.

(Example) Hereinafter, an example in which a spin coating apparatus of the present invention is applied to a resist coating apparatus for forming a resist film on the surface of a semiconductor wafer, etc. will be described with reference to the drawings.

A mounting table 12 that holds a workpiece 11 such as a semiconductor wafer using a vacuum chuck or the like is connected to a rotating mechanism 13 that rotates the workpiece 11 together with the mounting table 12 at high speed.

A discharge nozzle 14 connected to a resist liquid supply mechanism 15 that supplies a fixed amount of, for example, a resist liquid as a liquid coating agent is disposed above the approximately central portion of the object 11 to be processed. A predetermined amount of resist liquid is supplied onto the surface of the object 11.

Further, the object 11 to be processed is surrounded by an upper cup 16 and a lower cup 17 to prevent the resist liquid discharged onto the object 11 from scattering to the outside. This upper cup 16 has an oblique portion 16b that is inclined outwardly and downwardly from the upper opening 16a, and this oblique portion 16b
Subsequently, a receiving portion 16c is formed, and a lower opening 16d
has a cylindrical shape with a larger diameter than the upper opening 16a,
It is fitted into the lower cup 17. Further, a cylindrical airflow control plate 16e is provided at the lower end of the upper opening 16a of the upper cup 16.

The receiving portion 16c of the upper cup 16 is formed by a vertical surface following the oblique portion 16b and having an inclination opposite to the inclination direction of the oblique portion 16b, that is, an inclined surface facing inward and downward. The oblique portion 16b is provided near the collision position of the resist particles scattered as the object 11 rotates, and as shown in FIG. 2, the angle formed by the oblique portion 16b and the object 11 is Preferably, θ1 is determined as follows.

That is, the resist liquid 23 discharged onto the object to be processed 11
A part of the resist liquid is scattered into the cup as flying particles 24 of the resist liquid as the object 11 rotates. At this time, assuming that the collision between the resist particles 24 and the cup is a perfectly elastic collision, the reflection at the oblique portion 16b of the upper cup 16 due to the flight of the object 11 in the tangential direction is - This occurs at an angle approximately equal to the incident angle θ2.

Here, 02 is expressed by the following equation.

θ2-90°-cos-' (r/R) (where, r is the radius of the object to be processed 11, and R is the inner radius of the upper cup 16 in the same plane as the upper surface of the object to be processed 11.) , the reflection at the oblique portion 16b of the upper cup 16 due to the flying object 11 in the normal direction occurs at an angle approximately equal to the incident angle θ3 with respect to a plane perpendicular to the wall surface. Here, θ3 is expressed by the following equation.

θ, −90″−(θ1+θ4) (where θ1 is the angle formed by the oblique portion 16b and the upper surface of the object to be processed 11, and θ indicates the apparent upward elevation angle when emitted from the object to be processed. ) Considering these values of θ2 and θ3, the flying particles 24 of the resist collide with the oblique part 16b in three-dimensional direction, and then repeat the secondary collision with the vertical surface of the upper part of the receiving part 16c, and then collide with the receiving part 16c. It is preferable to determine the angle θ1 formed by the oblique portion 16b and the upper surface of the workpiece 11 so that the angle θ1 is 15°.

The lower cup 17 has an inner cup portion 18 that is inclined outwardly and downwardly from the lower part of the object to be processed 11 to prevent resist particles from entering the lower side of the object to be processed 11, and an opening 19b for draining liquid. The outer cup part 19 has a drain groove 19a whose bottom part is slightly inclined toward the drain opening 19b, and further includes an exhaust opening 19c and a drain groove 19a at the lower peripheral part of the outer cup part 19. It has a hollow cylindrical shape and has an opening 19d into which the rotating shaft of the stand 12 is loosely inserted. A drain pipe 20 for discharging the resist waste liquid to the outside is connected to the drain opening 19b.

An exhaust mechanism 22 is connected to an exhaust opening 19C provided at the lower part of the outer cup portion 19 of the lower cup 17 via an exhaust pipe 21 in order to prevent the resist liquid from scattering to the outside and to prevent any adverse effects caused by splashes. The exhaust mechanism 22 exhausts the interior of the chamber formed by the upper cup 16 and lower cup 17.

In the spin coating apparatus having the above configuration, the workpiece 11 such as a semiconductor wafer is placed on the mounting table 12, and is suctioned and held on the mounting table 12 by a vacuum chuck or the like, and the workpiece 11 is rotated together with the mounting table 12. 13 for example 400
The resist liquid supply mechanism 15 is rotated at approximately Or, p, and m.
A resist liquid is supplied and coated onto the surface of the object to be processed 11 from a discharge nozzle 14 connected to the resist liquid. Also at this time, exhaust mechanism 2
2 to exhaust air from inside the cup.

At this time, as shown in FIG. 2, the flying particles 24 of the resist liquid 23 scattered into the cup as the object 11 rotates in the direction of the arrow shown in the figure are removed from the oblique portion 16b of the upper cup 16.
First, the liquid collides with the vertical surface of the upper part of the receiving part 16c, and then, after a liquid pool 25 is formed in the receiving part 16c, the liquid drain groove 19a (not shown in the figure) (shown in Figure 1) and is discharged from the drainage opening 19b. Here, an exhaust flow (indicated by a dotted arrow A in the figure) is formed by an exhaust mechanism 22 (not shown in the figure, but shown in FIG. 1).

), an upward air current (indicated by a dotted arrow B in the figure) is generated due to the rotation of the object 11, etc., but the mist particles of the flying particles 24 generated by collision with the inner wall of the upper cup 16 are absorbed by the receiving part. 16c, which is apparently blocked from the upward airflow, and also forms a liquid pool 25, which is less susceptible to the influence of the upward airflow, and forms mist particles that are scattered onto the object 11 to be treated. There's nothing to do. Further, a very small amount of mist particles that fly toward the object 11 during the flight of the flying particles 24 or during the primary collision at the oblique portion 16b rise with the upward airflow, but are controlled by the airflow control plate 16e to It is ejected without flying up.

Therefore, according to the spin coating apparatus of this embodiment having the above-mentioned configuration, it is possible to effectively prevent the generation of mist particles of liquid coating agent particles scattered from the object to be treated, and even the very small amount of mist particles generated can be prevented from being generated. There is almost no scattering on the object, and therefore the number of liquid coating agent particles adhering to the surface of the object to be treated can be significantly reduced.

Further, in the above-described embodiments, the oblique portion of the upper cup is configured with an inclined surface, but the present invention is not limited to this. For example, as shown in FIG.
The same effect as in the above-mentioned embodiment can be obtained by configuring 6b to be a curved surface and repeating multiple collisions before reaching the receiving portion 16C. In short, a cup having a cross-sectional shape is provided in the direction in which the object to be treated is contained, and the structure is such that the object does not scatter onto the receiving plate.

[Effects of the Invention] As explained above, the spin coating apparatus of the present invention prevents deterioration of the uniformity of the coating film formed by the liquid coating agent on the surface of the workpiece (as the workpiece rotates). The mist particles that are formed when flying liquid coating particles collide with the inner wall of a cup can be suppressed from flying toward the object to be treated, and the number of liquid coating agent particles that adhere to the surface of the object to be treated can be significantly reduced. be able to.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a spin coating apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view showing an enlarged main part of FIG. 1, and FIG. 3 is a main part showing a modification of FIG. 1. Enlarged cross-sectional view of the section,
FIG. 4 is a configuration diagram showing an example of a conventional spin coating apparatus. DESCRIPTION OF SYMBOLS 11... Processing object, 13... Rotation mechanism, 15... Resist liquid supply mechanism, 16... Upper cup, 16b... Oblique part, 16c...
Receiving part, 17...lower cup. Applicant Chill Kyushu Co., Ltd. Agent Patent Attorney Sasa Suyama - Item 3, No. 40

Claims (1)

[Scope of Claims] A spin coating apparatus in which a liquid coating agent is supplied to the surface of an object to be treated, and a cup receives the liquid coating agent that is generated and scattered when the object is spin-coated, comprising the steps of: A slanted portion is provided in the vicinity of a collision position of the liquid coating agent that is scattered as the object to be treated rotates, and a receiving portion for the liquid coating agent after colliding with the slanted portion is provided in the cup. Spin coating equipment.