Cleaning and liquid contact with solids – Processes – Hollow work – internal surface treatment
Reexamination Certificate
2000-02-22
2001-01-09
Carrillo, Sharidan (Department: 1746)
Cleaning and liquid contact with solids
Processes
Hollow work, internal surface treatment
C134S022100, C134S022110, C134S022140, C134S022190, C134S025400, C134S042000, C134S170000, C134S171000, C134S198000, C134S199000, C134S16600C, C134S16900A, C422S091000, C422S105000
Reexamination Certificate
active
06170494
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to a cleaning apparatus for nozzles used in semiconductor processes and, more particularly, to a cleaning apparatus for photoresist dispensing nozzles, the cleaning apparatus having a cleaning solvent inlet that is positioned and configured to squirt the cleaning solvent directly onto the photoresist dispensing nozzles.
2. Description of the Related Art
Photoresist used during photolithography is dispensed onto semiconductor wafers using a plurality of nozzles. When these nozzles are not being used, they are returned to their home positions. The home positions of the nozzles correspond to their storage locations in a cleaning apparatus.
A conventional cleaning apparatus
10
in which the nozzles are stored is illustrated in
FIG. 1
as an exploded view. The cleaning apparatus
10
includes a nozzle base
20
, a thinner pot
30
, a solvent bath or catch pan
40
, and a drain
50
. Each of these components has openings corresponding to four photoresist dispensing nozzles
11
,
12
,
13
,
14
.
In their home positions, the photoresist dispensing nozzles
11
-
14
are inserted into corresponding openings
21
,
22
,
23
,
24
of the nozzle base
20
. The tips of the nozzles, when inserted, extend into corresponding openings
31
,
32
,
33
,
34
of the thinner pot
30
, near the bottom of the thinner pot
30
, as shown in
FIG. 2
, which shows a side cross-sectional view of the conventional cleaning apparatus
10
.
While the nozzles are in their home position, photoresist that remains in the nozzles dries up and begins to clog them up, especially at the tip and when the nozzles sit idle for any length of time. When any one of such nozzles is used to dispense photoresist during the photolithography process, dried photoresist particles become dispensed onto the semiconductor wafer and leads to defects. In some cases, little or no photoresist is dispensed due to clogging.
Three different techniques have been used to combat this problem. First, maintenance technicians remove the nozzles and manually clean each nozzle with a photoresist cleaning solvent. Second, the nozzles undergo a dummy dispense procedure. In this procedure, the photoresist is dispensed through the nozzles while they are in their home positions. This procedure keeps the nozzle tips continuously wet in an effort to prevent the photoresist remaining at the nozzle tips from drying up. The dispensed photoresist is dumped through the drain
50
. Third, photoresist cleaning solvent is introduced through an inlet
60
. The cleaning solvent that is introduced floods the solvent catch pan
40
but does not come in contact with the nozzles. At best, the nozzles are moistened from the solvent vapors, but this is not sufficient to prevent the nozzle from clogging.
SUMMARY OF THE INVENTION
The invention provides a cleaning apparatus for photoresist dispensing nozzles which has one or more solvent needles positioned to oppose corresponding nozzle or nozzles that are stored in their home positions so that, as photoresist cleaning solvent is introduced through the needles, the photoresist cleaning solvent is squirted directly at the nozzles to clean the nozzles and keep them from clogging. The squirting of the photoresist cleaning solvent through the needles preferably occurs at a specified interval to prevent the photoresist remaining in the nozzles from drying up.
Additional objects, features and advantages of the invention will be set forth in the description of preferred embodiments which follows.
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patent: 4977911 (1990-12-01), Vetter
patent: 5405087 (1995-04-01), Waryu et al.
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Kent Eric
Marinaro Vincent L.
Wakamiya Ted
Advanced Micro Devices , Inc.
Carrillo Sharidan
Foley & Lardner
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