Photography – Fluid-treating apparatus – Fluid application to one side only of photographic medium
Reexamination Certificate
1999-05-14
2001-05-22
Rutledge, D. (Department: 2851)
Photography
Fluid-treating apparatus
Fluid application to one side only of photographic medium
C396S611000, C396S627000, C118S052000, C427S240000
Reexamination Certificate
active
06234692
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to improved apparatus for fabricating semiconductor devices having a nozzle and a spin chuck, and more particularly, to an apparatus with a cover, spaced apart from and confronting the wafer surface, for protecting wafers from solutions used to fabricate the semiconductor devices.
2. Description of the Related Art
Generally, semiconductor devices are created by depositing various insulating or metallic layers on a semiconductor wafer to form a multiple layer structure. Desired circuit patterns are formed on the layers according to the properties of the respective semiconductor devices.
The circuit patterns are formed by photolithography processes, which generally comprise coating a photoresist on the wafer, aligning a photo mask having the circuit pattern formed thereon with the wafer, and then exposing selected areas of the photoresist consistent with the pattern. The exposed portion of the photoresist is removed using a developing solution so as to form a photoresist pattern. Thereafter, an etching process is performed using the photoresist pattern as an etching mask to thereby form the desired circuit pattern.
During the photolithography process, specific solutions (e.g., solutions used in the semiconductor device fabrication process or developing solutions) are sprayed onto the substrate using a nozzle and a spin chuck as shown in FIG.
1
. The spin chuck
12
secures the wafer W thereon, usually via vacuum suction, and rotates it at a specific speed. A specific solution
13
is sprayed through the nozzle
14
and onto the wafer W surface. More than one nozzle
14
may be provided, and the nozzle locations may be varied according to the process steps and operating conditions.
As the solution
13
is sprayed through the nozzle
14
, the wafer W is rotated by rotating the spin chuck
12
, so that the solution
13
is uniformly dispersed or coated along the entire wafer surface. However, as the solution
13
reaches the edge portion of the wafer W, it is scattered due to the centrifugal force of the rotating wafer W.
A bowl
18
, provided inside a process chamber
16
, surrounds the spin chuck
12
, nozzle
14
, and wafer W, to prevent the solution
13
supplied onto the wafer W from being scattered onto the inner wall of the process chamber
16
. However, some of the solution
13
contacting the bowl
18
is undesirably reflected back onto the wafer W, as shown by the arrows in
FIG. 1
, which serves as a source for particle generation. The unwanted solution
13
reflected from the bowl
18
may cause pattern bridges and profile failures during the formation of the pattern. Such defects require the wafer W to be rejected or reworked, thereby resulting in a reduction in productivity.
To minimize the unwanted reflected solution, conventional procedures seek to precisely control the process parameters, such as the viscosity of the solution
13
or the rotation speed of the spin chuck
12
. However, such process control parameters must take into account the desired parameters of the overall fabrication process, and as such, the process control ranges are limited.
SUMMARY OF THE INVENTION
The present invention is directed to an apparatus for fabricating semiconductor devices with a nozzle, a cover and a spin chuck that minimizes the occurrence of pattern formation failures during the semiconductor device fabrication process.
To achieve this and other advantages, and in accordance with the purpose of the present invention as embodied and broadly described, the apparatus for fabricating semiconductor devices comprises a spin chuck configured for mounting a wafer thereon and operative to rotate the wafer. A nozzle is arranged above the spin chuck, through which a solution is supplied to a surface of the wafer mounted on the spin chuck. A bowl surrounds the spin chuck, the bowl have a width greater than a diameter of the wafer mounted to the spin chuck, and a height greater than a combined height of the wafer mounted to the spin chuck. A cover is spaced apart from and confronts the spin chuck having the wafer mounted thereon. The cover has an opening through which a distal end of the nozzle passes so as to spray the solution onto the wafer surface while the cover is disposed over the wafer surface. The cover prevents any solution reflected back from the bowl from reaching the wafer surface.
The spin chuck and wafer cover may each be capable of vertical movement. The cover is preferably spaced 2 mm to 3 mm from the wafer surface.
If a plurality of nozzles are employed, the cover would have a corresponding plurality of openings to accommodate the nozzles passing there through. One or more of the openings may be radially elongated, thereby forming a slot in the cover, so that the nozzle may move back and forth in the radial direction along the slot.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
REFERENCES:
patent: 4889069 (1989-12-01), Kawakami
patent: 5439519 (1995-08-01), Sago et al.
patent: 5591264 (1997-01-01), Sugimoto et al.
patent: 5772764 (1998-06-01), Akimoto
Jones Volentine, LLC
Rutledge D.
Samsung Electronics Co,. Ltd.
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