Fluent material handling – with receiver or receiver coacting mea – Processes
Reexamination Certificate
1999-06-18
2001-01-23
Douglas, Steven O. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Processes
C141S083000, C141S095000, C222S056000, C073S001220
Reexamination Certificate
active
06176274
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to semiconductor fabrication, and more particularly to photolithography in semiconductor fabrication.
BACKGROUND OF THE INVENTION
Photolithography is conventionally used in the fabrication of semiconductor devices. It is typically performed using a device called a photolithography track. An important aspect of photolithography is the development of the photoresist. The dimensions of the photoresist pattern is important in the fabrication of semiconductor device since an etch or implantation of the substrate is performed based upon the photoresist pattern. The photoresist is patterned by a mask. The masked photoresist is then exposed to light from a light source. After exposure, developer is applied to remove the mask and exposed portions of the photoresist, leaving a patterned photoresist behind. The developer is typically a base and water mixture. Photolithography is well known in the art and will not be discussed in detail here.
FIG. 1
illustrates a portion of a conventional photolithography track. The track
100
includes a wafer
102
which may be spun by a chuck and motor
104
. While the wafer
102
is spinning, a developer dispenser
106
equipped with a nozzle
108
moves over the spinning wafer
102
and applies an amount of developer to remove the mask and exposed portions of the photoresist, as described above. The dispenser
106
then moves back and rests in a nozzle block
110
which protects the nozzle
108
when the dispenser
106
is not in use. A drain pipe
112
is coupled to the nozzle block
110
for draining any excess developer from the nozzle block
110
.
An important parameter in controlling the dimensions and shape of the patterned photoresist is the amount of developer applied. The amount may be determined from the flow rate and application time of the developer. However, it is often more accurate to measure the volume of the developer dispensed from the nozzle
108
. A conventional method of performing this volume check involves dispensing the developer at the point of use into a container and then transferring the developer from this container to a volume measuring apparatus. Because the location of the nozzle
108
in the track
100
, there is often little room to place a container under the nozzle
108
so that it can catch the developer which is dispersed. Even when a container can be so placed, there is typically some spillage of developer when it is transferred from the container to the measuring apparatus. The spilled developer may then contact parts of the track
100
, such as electronic circuitry and wiring, which can lead to corrosion and/or premature failure of those parts. The spilled developer may also results in an inaccurately low volume measurement.
Accordingly, what is needed is an improved method and system for measuring fluid volume in a photolithography track. The method and system should provide a more accurate measurement of developer volume. The present invention addresses such a need.
SUMMARY OF THE INVENTION
The present invention provides a method and system for measuring a fluid in a photolithography track. The method includes dispensing the fluid in a photolithography track into a self-contained reservoir, and measuring the volume of the fluid using the self-contained reservoir. In a preferred embodiment, the reservoir receives the fluid from the dispenser through a drain pipe. By measuring the volume of fluid in this manner, spillage of fluid is prevented because the volume measuring apparatus in accordance with the present invention is self-contained. This prevents corrosion and other damage to the parts of the photolithography track which come into contact with the spilled fluid. With no spillage, a more consistent volume measurement is obtained. The volume measurement is also much quicker to perform than conventional methods.
REFERENCES:
patent: 4597507 (1986-07-01), Rosenblum et al.
patent: 5131591 (1992-07-01), Gill
patent: 5377902 (1995-01-01), Hayes
Marinaro Vincent Lani
Pike Christopher Lee
Advanced Micro Devices , Inc.
Douglas Steven O.
Sawyer Law Group LLP
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