Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Forming nonplanar surface
Reexamination Certificate
2001-01-29
2003-04-15
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Forming nonplanar surface
C430S311000, C430S328000
Reexamination Certificate
active
06548228
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of and an apparatus for developing an exposed photoresist coated on the surface of a silicon wafer, with a developing liquid, a development control apparatus for controlling various components of a developing apparatus, and an information storage medium which stores, as software, a program for enabling a computer to perform various processing operations.
2. Description of the Related Art
At present, fine interconnection patterns of semiconductor circuit devices are formed by photolithography. According to the photolithographic process, it is necessary to develop an exposed photoresist coated on the surface of a silicon wafer with a developing liquid by a developing apparatus.
One conventional developing apparatus will be described below with reference to
FIGS. 1
a
,
1
b
through
5
of the accompanying drawings. The conventional developing apparatus, denoted by
100
, processes silicon wafer
101
with a photoresist coated on its surface. As shown in
FIG. 4
a
, developing apparatus
100
has wafer chuck mechanism
102
as a wafer holding means. Wafer chuck mechanism
102
is mounted on the upper end of rotatable shaft
103
which extends vertically. Silicon wafer
101
is detachably held by wafer chuck mechanism
102
such that the surface coated with the photoresist lies horizontally and faces upwardly.
Rotatable shaft
103
with wafer chuck mechanism
102
mounted on its upper end is rotatably supported by wafer rotating mechanism
104
(see
FIG. 3
) as a wafer rotating means which comprises a drive motor or the like. Wafer rotating mechanism
104
rotates silicon wafer
101
supported by wafer chuck mechanism
102
in a horizontal plane.
As shown in
FIG. 3
, developing apparatus
100
also has developing liquid supply mechanism
105
as a developing liquid supply means which comprises a tank and a pump, and cleaning liquid supply mechanism
106
as a cleaning liquid supply means which comprises a tank and a pump. Developing liquid supply mechanism
105
supplies developing liquid
107
comprising an aqueous alkaline liquid to the surface of silicon wafer
101
held by wafer chuck mechanism
102
. Cleaning liquid supply mechanism
106
supplies pure water
108
as a cleaning liquid. Developing liquid supply mechanism
105
has developing nozzle
109
, and cleaning liquid supply mechanism
106
has cleaning nozzle
110
. Developing nozzle
109
and cleaning nozzle
110
are movably supported by nozzle moving mechanism
111
. As shown in
FIGS. 1
a
through
2
b
, nozzle moving mechanism
111
moves developing nozzle
109
and cleaning nozzle
110
between a position which faces the surface of silicon wafer
101
held by wafer chuck mechanism
102
and a position retracted away from the surface of silicon wafer
101
.
Developing nozzle
109
has a slit structure capable of supplying a screen of developing liquid
107
diametrically across silicon wafer
101
, which is of a disk shape, at the center of silicon wafer
101
. Cleaning nozzle
110
comprises a slender pipe capable of supplying pure water
108
to a central position on silicon wafer
101
.
As shown in
FIG. 3
, wafer rotating mechanism
104
, developing liquid supply mechanism
105
, cleaning liquid supply mechanism
106
, and nozzle moving mechanism
111
are connected to operation control apparatus
112
comprising a computer as a development control apparatus. A control program for controlling a developing process is installed in operation control apparatus
112
. Based on the installed control program, operation control apparatus
112
controls operation of the above mechanisms
104
,
105
,
106
,
111
to perform the developing process.
Developing apparatus
100
can develop an exposed photoresist coated on the surface of the silicon wafer
101
with developing liquid
107
supplied thereto. Supplied developing liquid can be washed away from the surface of the silicon wafer
101
by pure water
108
.
More specifically, as shown in
FIG. 4
a
, silicon wafer
101
whose surface is coated with a photoresist is horizontally held by wafer chuck mechanism
102
. Then, as shown in
FIG. 5
, silicon wafer
101
held by wafer chuck mechanism
102
is rotated at a high speed by wafer rotating mechanism
104
.
In a period {circle around (1)} shown in
FIG. 5
, developing nozzle
109
of developing liquid supply mechanism
105
is moved to a position facing the surface of silicon wafer
101
by nozzle moving mechanism
111
. Thereafter, as shown in
FIG. 4
b
, in a period {circle around (2)} shown in
FIG. 5
, developing liquid supply mechanism
105
supplies developing liquid
107
to the surface of silicon wafer
101
which is being rotated at a high speed.
While developing liquid
107
is being supplied to the surface of silicon wafer
101
, the rotation of silicon wafer
101
is gradually decelerated to a predetermined speed, after which the supply of developing liquid
107
is stopped. As shown in
FIG. 4
c
, a puddle of developing liquid
107
is now formed on the surface of silicon wafer
101
. In a period {circle around (3)} shown in
FIG. 5
, the puddle of developing liquid
107
is maintained on the surface of silicon wafer
101
to develop the exposed photoresist.
Developing nozzle
109
is moved to the position away from the surface of silicon wafer
101
by nozzle moving mechanism
111
. At the same time, cleaning nozzle
110
of cleaning liquid supply mechanism
106
is moved to the position facing the surface of silicon wafer
101
by nozzle moving mechanism
111
.
After a predetermined developing time has elapsed, silicon wafer
101
is rotated at a high speed. As shown in
FIG. 4
d
, in a period {circle around (4)} shown in
FIG. 5
, pure water
108
is supplied to the surface of silicon wafer
101
which is being rotated at a high speed. Supplied pure water
108
cleans the surface of silicon wafer
101
, removing developing liquid
107
from the surface of silicon wafer
101
.
The supply of pure water
108
is stopped after elapse of a certain time. As shown in
FIG. 4
e
, in a period {circle around (5)} shown in
FIG. 5
, silicon wafer
101
is continuously rotated at a high speed even after the supply of pure water
108
is stopped, drying the surface of silicon wafer
101
with air.
In illustrated conventional developing apparatus
100
, developing nozzle
109
and cleaning nozzle
110
are supported by nozzle moving mechanism
111
for movement between the position facing the surface of silicon wafer
101
and the position retracted away from the surface of silicon wafer
101
. However, as shown in
FIGS. 6
a
and
6
b
, another conventional developing apparatus
200
has developing nozzle
109
and cleaning nozzle
110
which are oriented toward the center of silicon wafer
101
.
With conventional developing apparatus
200
, it is not possible to eject pure water
108
vertically from cleaning nozzle
110
to the surface of silicon wafer
101
. However, since it is not necessary to move developing nozzle
109
and cleaning nozzle
110
to the overlapping position, developing nozzle
109
and cleaning nozzle
110
do not need to be replaced with each other.
Therefore, a developing process can quickly be completed as developing nozzle
109
and cleaning nozzle
110
are not required to move in the developing process. However, even in this case, developing nozzle
109
and cleaning nozzle
110
are moved for the replacement of silicon wafer
101
.
With conventional developing apparatus
100
,
200
, the exposed photoresist coated on the surface of silicon wafer
101
can be developed with developing liquid
107
, and developing liquid
107
can be washed away from the surface of silicon wafer
101
with pure water
108
.
However, actual developing processes performed on silicon wafer
101
by conventional developing apparatus
100
,
200
have resulted in many developing defects. Attempts that have been made to find out causes of such developing defects have revealed that when developing liquid
107
Choate Hall & Stewart
NEC Corporation
Schilling Richard L.
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