Photography – Fluid-treating apparatus – Fluid application to one side only of photographic medium
Reexamination Certificate
1998-01-04
2001-02-20
Rutledge, D. (Department: 2851)
Photography
Fluid-treating apparatus
Fluid application to one side only of photographic medium
C396S574000, C396S627000, C118S326000, C118S052000, C430S325000
Reexamination Certificate
active
06190063
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a developing method and apparatus capable of controlling the progress of development of a predetermined region of a substrate such as a semiconductor wafer during a developing process, to accelerate the development and thereby form a circuit pattern on the substrate so that line widths thereof may be uniform.
In a coating-development system for carrying out a photolithography process during the manufacture of semiconductor devices, for example, a resist coating process is performed in which a resist film is formed on the surface of a semiconductor wafer (hereinafter merely referred to as “wafer”) and also a developing process is performed in which the wafer is developed after being applied with the resist and exposed to light.
In the developing process, a wafer, on which light has been irradiated according to a predetermined circuit pattern and which has been subjected to a postexposure-baking process and a cooling process, is transported to a developing unit and mounted to a spin chuck. A developer is supplied from a developer feed nozzle and applied to the entire surface of the wafer to a thickness of, for example, 1 mm. The wafer is then left at rest for a predetermined time with the developer applied thereto, and while the wafer is left to stand, development progresses due to natural convection. The wafer is thereafter rotated by the spin chuck so that the developer may be shaken off, and then a rinsing liquid is discharged from a rinse feed nozzle to wash off the developer remaining on the wafer. Subsequently, the spin chuck is rotated at high speed, whereby the developer and the rinsing liquid remaining on the wafer fly off and the wafer becomes dry. This completes a series of steps of the developing process.
Meanwhile, in recent years, there is an increasing demand for miniaturization of circuit patterns formed on wafers, and to this end, development should desirably be caused to progress so that the line widths of the resulting circuit pattern may be uniform over the entire region of the wafer.
During the development, however, the developer merely remains stationary on the wafer as stated above, and the progress of the development depends entirely upon natural convection of the developer. Further, the line widths of a circuit pattern are affected not only by conditions of the exposure process such as the exposure time and the amount of light exposure, but also by the temperature of the developer, the developing time, etc., and thus it is difficult to cause the development of a circuit pattern to progress in such a manner that the line widths of the resulting circuit pattern are uniform over the entire region of the wafer.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a developing method and apparatus capable of controlling the development of a substrate so that the line widths of a circuit pattern formed on the substrate may be uniform.
According to a first aspect of the present invention, there is provided a developing method for performing a developing process by applying a developer to a surface of a substrate which has been subjected to an exposure process, wherein the method comprises the step of supplying a fluid to the developer on the substrate when the developer is applied to the surface of the substrate, to thereby control the developing process.
According to a second aspect of the present invention, there is provided a developing method for performing a developing process by applying a developer to a surface of a substrate which has been subjected to an exposure process, wherein the method comprises the step of controlling temperature and humidity of an atmosphere surrounding the substrate when the developer is applied to the surface of the substrate.
According to a third aspect of the present invention, there is provided a developing apparatus for performing a developing process by applying a developer to a surface of a substrate which has been subjected to an exposure process, wherein the apparatus comprises:
a supporting member for supporting a substrate; a developer feed nozzle for supplying and thereby applying a developer to a surface of the substrate; and
a fluid supply mechanism for supplying a fluid for controlling the developing process to the substrate applied with the developer.
According to the first aspect of the present invention, when the developer is applied to the surface of the substrate, the fluid is supplied to the developer on the substrate to control the developing process, whereby the development can be made to progress properly and unevenness of development can be eliminated. Consequently, circuit patterns having desired and yet uniform line widths can be formed on substrates. Specifically, in cases where there is a difficulty in obtaining desired line widths over the entire surface of the wafer, the fluid may be supplied uniformly to the entire surface of the substrate to control the developing process. Also, the fluid may be supplied locally to a region of the wafer where the line widths of the circuit pattern are liable to become uneven, for example, and in this case, the temperature, thickness, liquid surface state, etc. of the developer in this region and thus the developing process can be controlled so that the line widths of the resulting circuit pattern may be uniform. Further, the fluid to be supplied may be high-humidity air, in which case evaporation of the developer is suppressed and the line widths can be prevented from becoming uneven due to reduction in temperature of the developer. Where air whose pH value has been controlled is supplied as the fluid, moreover, substances that adversely affect the development, such as ammonia, can be removed.
According to the second aspect of the present invention, when the developer is applied to the surface of the substrate, the temperature and humidity of the atmosphere surrounding the substrate are controlled to thereby control evaporation of the developer, whereby local reduction in temperature of the developer induced by heat of vaporization can be suppressed and the line widths can be prevented from becoming uneven.
According to the third aspect of the present invention, since the fluid for controlling the developing process is supplied to the substrate applied with the developer, failure of expected development and unevenness of development can be eliminated and circuit patterns having desired and yet uniform line widths can be formed on substrates.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
REFERENCES:
patent: 5342738 (1994-08-01), Ikeda
patent: 5700629 (1997-12-01), Kakumaru
patent: 5944894 (1999-08-01), Kitano et al.
patent: 2-46465 (1990-02-01), None
patent: 6-310417 (1994-11-01), None
Rader Fishman & Grauer
Rutledge D.
Tokyo Electron Ltd.
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