JPS5941788B2 - Rotary coating device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a rotary coating device.

The method of coating a viscous fluid such as hot resist on a semiconductor substrate as a sample substrate, which has been commonly used in the past, is as shown in FIG. , the direct and indirect connections are made, and a fixed axis type rotary coating device is used, the basic structure of which is to rotate and drive the rotary table 1 by rotating the motor 3 at high speed. After holding the semiconductor substrate 4 by vacuum adsorption or the like and dropping an appropriate amount of photoresist 5 onto the semiconductor substrate 4, the rotary table 1 is rotated at high speed to remove the photoresist 5 on the semiconductor substrate 4 by centrifugal force. This method forms a thin layer of photoresist 5 on semiconductor substrate 4 by diffusing it radially. At this time, when the rotary table 1 rotates counterclockwise, the photoresist 5 on the surface of the semiconductor substrate 4 diffuses toward the periphery on the surface of the semiconductor substrate 4 along roughly radial trajectories as indicated by arrows 6 in FIG. The excess photoresist that has reached the peripheral portion is released from the semiconductor substrate 4, thereby forming a substantially uniform photoresist thin film on the surface of the semiconductor substrate 4.

However, in such a conventional method, by diffusing the photoresist 5 radially from the center to the periphery,
Because it depends on the mechanism for forming a thin film, the semiconductor substrate 4
When an uneven part, especially a convex part, or an obstacle T such as dust exists on the surface, a fan-shaped shadow part 8 is formed from the point where the obstacle 1 exists toward the peripheral part, and the shadow part 8 In this case, the photoresist film thickness inevitably decreases, and as a result, a photoresist thin film with partially different film thicknesses (including pinholes, etc.) is formed on the semiconductor substrate 4.

This may cause pattern collapse in photoetching using fine patterns such as LSI. Furthermore, due to the use of a fixed-axis rotation device, the center of rotation of the semiconductor substrate 4 is stationary, and due to factors such as weaker centrifugal force acting on the photoresist 5 near the center, the film in the center is weaker than in the periphery. Defects resulting in non-uniform thickness also occur.

The present invention eliminates the defects observed in the conventional coating method of viscous fluid, and by rotating the sample substrate and moving the axis of rotation of the rotary disk that supports the sample substrate, a homogeneous viscous fluid can be applied. An object of the present invention is to provide a rotary coating device capable of forming a thin film of 100% on the surface of a sample substrate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The rotary coating device of the present invention will be described below based on embodiments with reference to the drawings.

FIG. 3 is a basic plan schematic diagram of the rotary coating device of the present invention, and FIG. 4 is a schematic cross-sectional diagram thereof.

The structure is a so-called rotation-revolution rock structure, and the rotation of the 1-drive motor 9 is transmitted to the main disk 11 through the main shaft 10.
A rotary bearing 12 is provided at a position f eccentric from the main shaft 10, and the shaft 14 of the auxiliary disc 13 is fitted into the bearing 12, so that the auxiliary disc 13 can rotate freely. The peripheral wall 15 of the auxiliary disk 13 is in pressure contact with the fixed peripheral wall 16f having a concentric circle with the main shaft 10.
The portion of the auxiliary disk 13 of No. 6 that is in contact with the peripheral wall 15 is preferably formed of a material having some elasticity and a coefficient of friction, such as hard rubber 17. Note that this may be formed on the peripheral wall 15 surface of the auxiliary disk 13. With the above configuration, if the main disk 11 is rotated by the rotation 1 drive motor 9, the main disk 11
The upper auxiliary disk 13 (also revolves along the fixed peripheral wall 16 surface f), and the auxiliary disk 13 itself also revolves around the axis 14,
Due to the friction of the fixed peripheral wall 16, a reverse rotational movement is performed.

For example, if the ratio of the outer diameter φ1 of the auxiliary disk 13 and the inner diameter φ2 of the fixed peripheral wall 16 is set to 8:10, and the rotation speed of the 1-drive motor 9 is driven once at 3000 RPM, the auxiliary disk 13 { will be driven at a high speed of 3000/3750 RPM. Performs orbital rotation.

In addition, the motion on the auxiliary disk 13 during one revolution is as shown in FIG. 5, as shown in FIG. On the auxiliary disk 13, it shows movements having various trajectories in arbitrary directions other than circular motion, such as following a trajectory.

Therefore, the semiconductor substrate 4 is placed on the auxiliary disk 13 as shown in FIG. After dropping the photoresist 5, if the auxiliary disk 13 is rotated and revolved at high speed by the driving motor 9, the photoresist 5 (or the photoresist 5) is deposited on the semiconductor substrate 4 with various trajectories as shown in an example of the trajectories in FIG. The surplus is then released from the surrounding area.

Therefore, in this coating method, the generation of shadows due to obstacles that occur in the conventional radial diffusion coating method from a fixed point is suppressed by the omnidirectional diffusion of the photoresist, and the entire surface of the semiconductor substrate 4 is coated with a homogeneous photoresist. A thin layer is formed. As explained above, in the rotary coating apparatus of the present invention, since the sample substrate rotates and revolves, the film thickness of the viscous fluid on the sample substrate is uniform, and it is possible to coat semiconductor devices such as photoetching fine patterns. It becomes possible to obtain the manufacturing process with good reproducibility, and the yield of manufacturing LSI etc. can be improved, which is of great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing the basic structure of a conventional rotary coating device, FIG. 2 is a schematic diagram showing the locus of motion of a viscous fluid during coating by the rotary coating device shown in FIG. 1, and FIG. FIG. 4 is a schematic plan view and a schematic cross-sectional view showing the basic structure of the rotary coating device of the present invention, FIG. 5 is a diagram showing the locus of the rotary coating device of the present invention during rotation and revolution coating, and FIG. 6 is a schematic diagram of the present invention. 1 is a schematic cross-sectional view of an embodiment of a rotary coating device of FIG. 4...Sample substrate, 9...Rotation 1 drive motor, 10...Main shaft, 11...Main disk, 12...Rotation Bearing, 13...Auxiliary disk, 14...Shaft, 16...Fixed peripheral wall.

Claims (1)

[Claims] 1. An auxiliary disk on which a substrate to be coated is arranged is installed eccentrically to a rotating main disk, and the auxiliary disk rotates on the main disk in a different manner from the main disk, thereby causing the substrate to rotate around its axis and around its axis. A rotary coating device characterized by uniformly coating a viscous fluid onto the substrate.