JPH03214722A - Resist coating device - Google Patents

Abstract

PURPOSE:To obtain a coating film with an improved uniformity in film thickness by providing a cover plate for covering an object to be coated at the upper part closely and opposing it and then providing an opening in the center for enabling this opening to be connected to a solvent steam supply means. CONSTITUTION:A cover plate 15 for covering a substrate 1 which is all object to be coated is provided at the upper part closely opposing it, an opening 15A is provided at least in the center of the cover plate 15, and the opening 15A is connected to a solvent steam supply means 17. Thus, solvent steam evaporated from the resist on the wafer 1 stagnates at a narrow space S between the wafer 1 and the cover plate 15, vaporization of the solvent is restricted, and then the solvent steam pressure in the central part, middle part, and peripheral part of the wafer 1 becomes approximately uniform by supplying solvent steam from the solvent steam supply means 17 to the space S. Thus, the resist spreads fully and is dried uniformly over nearly the entire surface, thereby obtaining a resist film with improved uniformity in film thickness.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a resist spin coating device for manufacturing semiconductor devices, etc., and aims to provide a resist coating device that can obtain a coating film with good film thickness uniformity. A cover plate 15 is disposed above the substrate 1, which is a body, to cover it, and the cover plate 15 has an opening 15A at least in its center, and the opening 15A is connected to the solvent vapor supply means l7. Configure it so that it communicates with the

[Industrial application field]

The present invention relates to a resist spin coating apparatus for manufacturing semiconductor devices and the like.

Electrodes and wiring of semiconductor devices are formed based on a resist pattern obtained by exposing a resist 1 coated on a wafer to ultraviolet rays, electron beams, etc. in a wafer processing step, and then developing it. Therefore, the pattern accuracy of the electrodes and wiring depends on the accuracy of the resist pattern, but it is known that the accuracy of the resist film thickness has a large influence on the width accuracy of the resist pattern. It is also known that the resist bulge that occurs at the wafer periphery causes dust to be generated during wafer handling.

Strict control of process conditions is required to suppress these variations in resist film thickness, but as semiconductor device patterns have become increasingly finer in recent years, controlling process conditions alone is not enough to achieve the desired film thickness uniformity. It's becoming difficult to obtain. Since further miniaturization is expected in the future, it is desired to develop a resist coating device that can obtain good film thickness uniformity.

[Conventional technology]

A conventional resist coating apparatus will be explained with reference to FIG. Second
The figure is a schematic sectional view showing a conventional general device. In the figure, l is a wafer to be coated.

Reference numeral 11 denotes a chuck, which vacuum-chucks the wafer 1.

(2) Reference numeral 2 is a rotating means consisting of a motor or the like, which rotates the chuck 11, which vacuum-chucks the wafer 1, at a desired number of revolutions. 23 is a resist nozzle, one end of which communicates with a resist supply means (not shown), and drops resist onto the wafer l from the other end. A cup 24 accommodates excess resist that is scattered when the wafer 1 rotates. An exhaust port 24A is provided at the bottom of the cup 24 to exhaust the vapor of the resist solvent.

To apply resist using this device, first drop the resist from the resist nozzle 23 onto the stationary wafer 1, then rotate the wafer 1 at a low speed to spread the resist over the surface of the wafer L, and then rotate the wafer 1 at a high speed to spread the resist. continues to gradually expand toward the desired film thickness. During this time, the solvent of the resist that has spread on the surface of the wafer 1 gradually evaporates and its viscosity increases, and eventually the resist stops spreading. At this point, the rotation of the wafer I is stopped and the resist coating is completed.

By the way, while the wafer 1 is rotating, the resist on the wafer 1 is exposed to wind according to the circumferential speed of the wafer l, but this wind speed is zero at the center of the wafer l and increases toward the periphery. The periphery is faster than the center《
The viscosity increases, and as a result, the film thickness at the periphery becomes larger than that at the center. Moreover, since the viscosity increases from the surface layer, the resist film swells, especially at the peripheral edge. In addition, since the wafer l is not perfectly circular and has an orientation flat (hereinafter referred to as an "orientation flat") to indicate the crystal orientation, airflow turbulence occurs at the periphery of the wafer 1 during rotation, and this also occurs at the periphery. This may cause the resist film to bulge in some areas.

In order to suppress the above-mentioned phenomenon in a general resist coating device, a specific example of the device is disclosed in Japanese Patent Laid-Open No. 62/1999, in which a cover plate having a hole in the center is disposed close to and facing above the object to be coated. It is disclosed in the publication No.-140674. this is,
The evaporation of the solvent is suppressed by causing the resist solvent vapor to stagnate between the object to be coated and the cover plate, and a portion of the solvent vapor is diffused to the outside from the center and periphery of the wafer, thereby improving the wafer processing. This is intended to equalize the vapor pressure of the above solvent.

[Problem to be solved by the invention]

However, when the purpose is to accurately transfer particularly fine patterns, it is said that even with the improved equipment mentioned above, it is not possible to obtain a coating film with a sufficiently uniform thickness. There was a problem. SUMMARY OF THE INVENTION An object of the present invention is to provide a resist coating apparatus capable of solving such problems and obtaining a coating film with good film thickness uniformity.

[Means to solve the problem]

According to the present invention, a cover plate 15 is disposed above the substrate 1, which is an object to be coated, and covers the substrate 1, and the cover plate 15 has an opening 15A at least in its center.
This can be achieved by using a resist coating apparatus characterized in that the opening 15A is in communication with the solvent vapor supply means 17.

[Effect]

In the present invention, since the cover plate is disposed directly above and facing the wafer, which is the object to be coated, the solvent vapor evaporated from the resist on the wafer stagnates in the narrow space between the wafer and the cover plate, and the solvent vaporizes. is suppressed. Furthermore, by supplying solvent vapor to this space from the solvent vapor supply means 17, the solvent vapor pressure in the center, middle and peripheral parts of Ueno\ becomes approximately uniform. As a result, the resist is sufficiently spread and then dried almost uniformly over the entire surface, resulting in a resist film with good thickness uniformity.

〔Example〕

An embodiment of a resist coating apparatus based on the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view showing one embodiment of the present invention. In the figure, 1 is a wafer to be coated.

Reference numeral 11 denotes a chuck, which vacuum-chucks the wafer 1. l
Reference numeral 2 denotes a rotating means consisting of a motor or the like, which rotates the chuck 11, which vacuum-chucks the wafer 1, at a desired number of revolutions.

Reference numeral 13 denotes a resist nozzle, one end of which communicates with a resist supply means (not shown), and drops resist onto the wafer 1 from the other end. A cup 14 is used to accommodate excess resist that is scattered when the wafer 1 rotates, and is moved up and down by a vertical movement mechanism (not shown). An exhaust port 14A is provided at the bottom of the cup 14 to exhaust the vapor of the resist solvent.

Reference numeral 15 denotes a cover plate, which is a circular plate having an outer diameter larger (approximately 1.3 times) than the wafer 1 to be coated and having an opening 15A in its center. 16 is a housing, which is fixed on the cover plate l5, and has a cavity 16A inside.
This cavity 16A communicates with the opening 15A of the cover plate l5. The above-mentioned resist nozzle 13 is fixed to this housing 16. This housing 16 is moved up and down by a vertical movement mechanism (not shown), and the cover plate 15
Also, the distance between the resist nozzle 13 and the wafer 1 can be changed.

17 is a solvent vapor supply means, which includes a container 17A and a gas pipe 1.
7B, a tube 17C, etc., fill a container 17A with about half of a solvent equivalent to that of the resist, and guide the vapor into the cavity 16A of the housing 16 through the tube 17c.
It is released from the opening 15A of the cover plate 15.

A gas pipe 17B is introduced into the container 17A, and by injecting pressurized nitrogen or the like into the solvent, it is possible to promote the evaporation of the solvent by bubbling and to send the vapor.

To apply resist with this device, first lower the cup 12, place the wafer l on the chuck 11 with the cover plate l5 and resist nozzle 13 raised, vacuum adsorb it, then apply the cover plate 15 and the resist nozzle 13 up. The nozzle 13 is closely opposed to the wafer 1 (the distance between the wafer 1 and the cover 15 is 10 mm or less), the cup 12 is raised, and resist is dripped from the resist nozzle 13 while the wafer 1 is stationary. Next, the wafer 1 is rotated at a low speed to spread the resist on the wafer 1, and when the wafer 1 is rotated at an even higher speed, the resist continues to gradually spread toward a desired film thickness. The solvent of the resist that has spread on the surface of the wafer 1 gradually evaporates and its viscosity increases, and eventually the resist stops spreading. During this time, the solvent vapor evaporated from the resist stagnates in the narrow space S between the wafer 1 and the cover plate l5, and is further supplied with solvent vapor from the solvent vapor supply means 17, so that the vaporization of the solvent is suppressed. As a result, the resist is sufficiently spread and then dried, resulting in a resist film with good thickness uniformity. In particular, the resist bulge at the periphery of the wafer 1 almost disappeared except for a part of the orientation flat.

The present invention is not limited to the above embodiments, but can be implemented with various modifications. For example, the object to be coated is not limited to a wafer, but other disc-shaped objects or rectangular plate-shaped objects such as photomasks are also effective. Further, the cover plate may have not only one hole in the center, but also a plurality of holes arranged radially.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a resist coating apparatus that can obtain a coated film with good film thickness uniformity with less resist swelling around the wafer periphery, which is a source of dust generation. This greatly contributes to improving yields in semiconductor device manufacturing processes.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention, and FIG. 2 is a schematic sectional view showing a conventional general device. In the figure, ■ is a wafer (substrate), 10, 11 is a chuck, 12 is a rotating means, 13. 23 is a resist nozzle; 14. 24 is a cup, 15 is a cover plate, 15A is an opening, and 17 is a solvent vapor supply means. l 1 mouth

Claims (1)

[Claims] In an apparatus for spin-coating a resist onto a substrate (1), a cover plate (15) is disposed above and close to and covering the substrate (1), which is an object to be coated; The cover plate (15
) has an aperture (15A) at least in its center, and the aperture (15A) communicates with a solvent vapor supply means (17).