Photography – Fluid-treating apparatus – Fluid application to one side only of photographic medium
Reexamination Certificate
1999-02-03
2001-07-10
Rutledge, D. (Department: 2851)
Photography
Fluid-treating apparatus
Fluid application to one side only of photographic medium
C118S320000, C427S299000, C430S323000
Reexamination Certificate
active
06257778
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for developing the surface of a substrate that has been coated with resist and exposed with developing solution and to an apparatus thereof.
2. Description of the Related Art
A mask is formed by coating resist on the surface of a semiconductor wafer (hereinafter referred to as wafer), radiating a light beam, an electron beam, an ion beam, or the like to the resist surface, and developing the resist. With the mask, a circuit pattern is formed on the surface of the wafer. At the developing step, a light exposed portion or a non-light-exposed portion in the exposing step is dissolved with developing solution such as alkali solution.
At such a developing step, the wafer is vacuum-held on a spin chuck having a vacuum holding function. A supplying nozzle that has many discharging holes formed corresponding to the diameter of the wafer is positioned above the wafer. The developing solution is placed as a liquid membrane on the surface of the wafer through the discharging holes. While the developing solution is being supplied through the discharging holes, the wafer is turned by 180°.
Thus, the developing solution placed on the wafer spreads out. In addition, the developing solution is further supplied. Consequently, a membrane of the developing solution with a predetermined thickness is formed on the entire surface of the wafer.
At the developing step, the wafer is not rotated by more than 180°. This is because the former developing solution is prevented from mixing with the new developing solution. In other words, the wafer is prevented from being unequally developed between the mixed portion and non-mixed portion.
SUMMARY OF THE INVENTION
However, in the above-described developing method, to supply the developing solution on the entire surface of the wafer with a predetermined thickness, it takes around one to two seconds. Thus, a time lag takes place between a portion at which the developing solution is supplied early and a portion at which the developing solution is supplied later.
The progress of the developing process depends on the contact time of the process region of the wafer and the developing solution. In other words, the progress of the developing process is proportional to the contact time.
When there is a time lag of the supplied developing solution, the portion to which the developing solution is supplied earlier is more developed than the portion to which the developing solution is supplied later. Thus, in the above-described method, the surface of the wafer is unequally developed. Thus, it is difficult to equally develop the wafer.
An object of the present invention is to provide a developing method for equally developing the surface of a substrate and a development apparatus thereof.
To solve the above-described problem, a first aspect of the present invention is a method for developing the surface of a substrate, comprising the steps of supplying developing solution to the surface of the substrate, and improving the developing function of the supplied developing solution so as to develop the surface of the substrate.
A second aspect of the present invention is an apparatus for developing a substrate having a first surface and a second surface, comprising a holding portion for holding the substrate, supplying means for supplying developing solution to the first surface of the substrate held by the holding portion, and developing function improving means for improving the developing function of the developing solution supplied to the first surface.
According to the present invention, when developing solution is supplied to the surface of a substrate, it is not developed. After the developing function of the developing solution is improved, the substrate is developed. Thus, even if there is a time lag of developing solution supplied to the surface of the substrate, it is equally developed.
These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of a best mode embodiment thereof, as illustrated in the accompanying drawings.
REFERENCES:
patent: 5626913 (1997-05-01), Tomoeda et al.
patent: 6000862 (1999-12-01), Okuda et al.
patent: 6033475 (2000-03-01), Hasebe et al.
patent: 63-175429 (1988-07-01), None
patent: 2-51160 (1990-02-01), None
patent: 3-153019 (1991-07-01), None
Konishi Nobuo
Toshima Takayuki
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Rutledge D.
Tokyo Electron Limited
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