Photography – Fluid-treating apparatus – Fluid application to one side only of photographic medium
Reexamination Certificate
2000-05-30
2001-07-31
Rutledge, D. (Department: 2851)
Photography
Fluid-treating apparatus
Fluid application to one side only of photographic medium
C396S611000, C118S052000
Reexamination Certificate
active
06267516
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-151362, filed May 31, 1999, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a developing apparatus and a developing nozzle used in the manufacture of a semiconductor device or a liquid crystal display (LCD) device, particularly, to a developing apparatus and a developing nozzle for development of a chemically amplified resist film in photolithography of a semiconductor device.
In a manufacturing process of a semiconductor device, a semiconductor wafer is coated with resist, and the coated resist film is baked, exposed to light and, then, developed. Used in such treatments are a coating-developing system disclosed in, for example, U.S. Pat. No. 5,664,254 and U.S. Pat. No. 5,700,127. The coating-developing system, which is used in combination with a light exposure apparatus in a photolithography for a semiconductor device, includes a resist coating unit and a developing unit.
In the developing unit, a wafer having a resist film formed thereon, said resist film bearing a light-exposed latent image, is held by a spin chuck, and a nozzle extending over the diameter of the wafer is positioned right above the wafer. Under this condition, the wafer is rotated to make at least half the complete rotation while supplying a developing solution from the discharge port of the nozzle onto the wafer. As a result, a film of the developing solution is formed in a uniform thickness over the entire upper surface of the wafer. The wafer having the film of the developing solution formed thereon is held stationary for a predetermined time to have the developing solution kept in contact with the resist film formed on the wafer so as to develop the light-exposed latent image formed in the resist film. The particular developing method is called a puddle development.
In the puddle development, it is desirable to make the total residence time (total contact time) of the developing solution uniform over the entire surface of the wafer in order to ensure uniformity of the line width of the circuit. Therefore, it is necessary to coat the entire surface of the wafer with the developing solution as promptly as possible and, thus, the developing solution is supplied from the supply source to the nozzle at a high pressure.
However, since the discharge port of the nozzle has a small diameter, a high supply pressure of the developing solution imparts an excessively large impact to the light-exposed latent image formed in the resist film, leading to nonuniformity in the line width. Particularly, since the line width of the pattern formed in a chemically amplified resist film is on the submicron order, a serious influence tends to be imparted to the light-exposed latent image formed in the resist film, if the developing solution discharged from the nozzle has a large colliding force.
It should also be noted that the developing nozzle is made of a resin having a high water repellency. Therefore, if the developing solution is discharged at a high speed, the discharge range of the developing solution tends to be narrowed when the developing solution is discharged from the discharge port, with the result that the developing solution tends to fail to be supplied to the entire region of the wafer so as to bring about undeveloped portions. The tendency is particularly prominent in the case of the scanning system in which the developing solution is discharged while the nozzle is moved along the wafer surface.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a developing apparatus that permits improving the uniformity of the line width and also permits preventing nonuniformity of resolution (nonuniform development).
Another object of the present invention is to provide a developing nozzle that permits suppressing the colliding force of the developing solution against the resist film and also permits uniformly supplying the developing solution over the entire region of the substrate.
According to a first aspect of the present invention, there is provided a developing apparatus, comprising a table on which is disposed a substrate having a resist coating film formed thereon, a nozzle for supplying a developing solution to the substrate disposed on the table, a liquid supplying mechanism for supplying the developing solution to the nozzle, and a moving mechanism for relatively moving the nozzle and the substrate, wherein the nozzle includes a liquid inlet port communicating with the liquid supplying mechanism, a liquid reservoir for temporarily storing the developing solution supplied from the liquid supplying mechanism through the liquid inlet port, a narrow passageway communicating with the bottom portion of the liquid reservoir to cause pressure loss of the developing solution coming from the liquid reservoir, a linear liquid discharge section having a discharge port passageway communicating with the narrow passageway, and a buffering member arranged within the discharge port passageway and in the vicinity of the outlet port of the narrow passageway, the buffering member weakening the strength of the developing solution coming out of the narrow passageway so as to weaken the impact given by the developing solution discharged from the discharge port to the resist coating film.
The buffering member is housed within the discharge port passageway so as to prevent the buffering member from coming out of the liquid discharge section. Also, it is desirable for the buffering member to be positioned above the lowermost portion of the liquid discharge section.
The buffering member, which consists of a single rod, extends from at least one end portion to the other end portion of the discharge port passageway. In this case, the both end portions of the rod-like buffering member are supported by the liquid discharge section. It is possible for the rod-like buffering member to have a circular cross section, an elliptical cross section or a gourd-shaped cross section. It is also possible for the rod-like buffering member to be externally threaded.
It is possible for the buffering member to consist of a plurality of granular bodies or lumps that are linearly arranged to extend from one end portion to the other end portion of the discharge port passageway. In this case, it is desirable for the plural granular bodies or lumps to be supported by the lower portion of the liquid discharge section.
It is possible for the narrow passageway to be open in the center at the bottom of the liquid reservoir and to consist of a large number of fine holes each having a diameter smaller than the clearance of the discharge port passageway. It is also possible for the narrow passageway to consist of a slit open in the center at the bottom of the liquid reservoir and having a width smaller than the width of the discharge port passageway.
The linear liquid discharge section is longer than at least the radius of the substrate. The nozzle of this type permits easily forming a layer of a developing solution on the substrate so as to facilitate formation of the puddle phenomenon.
According to a second aspect of the present invention, there is provided a developing nozzle used in a photolithography process, comprising a liquid inlet port for receiving a developing solution, a liquid reservoir for temporarily storing the developing solution received through the liquid inlet port, a narrow passageway communicating with the bottom portion of the liquid reservoir and serving to lower the pressure of the developing solution coming from the liquid reservoir, a linear liquid discharge section having a discharge port passageway communicating with the narrow passageway, and a buffering member arranged within the discharge port passageway and positioned in the vicinity of the outlet port of the narrow passageway, the buffering member serving to weaken the strength of the developing solution coming out of the nar
Akimoto Masami
Kosugi Hitoshi
Nagamine Shuichi
Nishiya Akira
Fulbright & Jaworski L.L.P.
Rutledge D.
Tokyo Electron Limited
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