Cleaning and liquid contact with solids – Processes – Using solid work treating agents
Reexamination Certificate
2000-10-03
2002-04-30
Markoff, Alexander (Department: 1746)
Cleaning and liquid contact with solids
Processes
Using solid work treating agents
C134S001000, C134S001300, C134S032000, C134S034000, C134S033000, C134S902000, C015S097100, C015S088200, C015S102000
Reexamination Certificate
active
06379469
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and method for washing a substrate, in which a substrate such as a semiconductor wafer or an LCD substrate is washed by scrubbing.
2. Discussion of the Background
In a process of manufacturing a semiconductor device such as an LSI, a surface of a wafer on which a circuit pattern is formed is required to maintain a strictly high cleanliness, making it necessary to wash the wafer surface frequently both before and after various process steps. Particularly, in a photolithography process, it is absolutely necessary to apply a washing treatment to a wafer surface.
A scrubber disclosed in, for example, Japanese Patent Disclosure (Kokai) No. 57-102024 or Japanese Patent Disclosure No. 62-259447 is used in the photolithography process for scrubbing the wafer surface for the washing purpose. In the scrubber disclosed in these prior art, a washing liquid is supplied onto a surface of a wafer revolved on its own axis. Also, a washing member such as a brush or sponge, which is kept rotated, is brought into contact with the revolving wafer surface so as to remove the foreign matter attached to the wafer surface.
FIGS. 1 and 2
collectively show a conventional front face washing section
101
. As shown in the drawings, the front face washing section
101
comprises a holder
103
having a washing liquid supply hole
102
formed in a central portion, and 6 washing members
104
held by the holder
103
. The washing section
101
is supported by a support mechanism (not shown) so as to be rotatable on its own axis and movable in a vertical direction. The washing member
104
consists of a columnar sponge having a tip portion cut to form a flat surface. A washing liquid such as pure water is supplied through the washing liquid supply hole
102
into each of the washing members
104
while the washing section
101
is kept revolved on its own axis. Under this condition, the tip portions of the washing members
104
are pressed against a front face, i.e., circuit pattern-forming face, of a wafer which is kept revolved on its own axis, so as to cleanse the wafer front face.
FIGS. 3 and 4
collectively show a conventional rear face washing section
111
. As shown in the drawings, the washing section
111
comprises a holder
112
having a washing liquid supply hole
115
formed in a central portion and a plurality of washing members
113
,
114
. The washing section
111
is supported by a supporting mechanism (not shown) so as to be rotatable on its own axis and movable in a vertical direction. The washing members consist of 8 brushes
113
and 4 sponges
114
. These brushes
113
and sponges
114
are used in combination in the conventional rear face washing section
111
partly because the rear face of the wafer tends to be stained more severely than the front face and partly because the rear face can be scrubbed more strongly than the front face. Each of these brushes
113
and sponges
114
has its tip portion cut to form a flat surface which is brought into contact with the wafer surface. A washing liquid such as pure water is supplied through the washing liquid supply hole
115
onto each of the washing members
113
,
114
, while revolving the washing section
111
on its own axis. Under this condition, the washing members
113
,
114
are pressed against a rear face (back face opposite to the circuit pattern-forming face), of the wafer W which is kept revolved on its own axis so as to cleanse the rear face of the wafer W.
In the conventional scrubbers
101
,
111
shown in
FIGS. 1
to
4
, only a slight inclination of the supporting arm (not shown) causes the tip portions (wafer-contact portions) of the sponges
104
,
114
to fail to be brought into contact uniformly with the wafer faces. In other words, peripheral portions alone of the sponges
104
,
114
are strongly pressed against the wafer faces. Since the contact pressure between the sponges
104
,
114
and the wafer face is locally concentrated, the entire wafer face cannot be washed uniformly. In addition, stains are attached to and remain on the peripheral portions alone of the sponges
104
,
114
. It follows that, if these sponges
104
,
114
are used repeatedly, a serious problem is brought about that the wafer faces are stained.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide an apparatus and method for washing a substrate, which is effective for preventing a mutual pressing force between a scrubbing member and a substrate surface from being locally concentrated and permits allowing a substrate-contact portion of the scrubbing member to be kept clean.
According to an aspect of the present invention, there is provided a substrate washing apparatus, comprising:
a spin chuck for holding and rotating a substrate;
a brushing section including a scrubbing member which is brought into contact with a washing surface of the substrate held on the spin chuck and revolved on its own axis together with rotation of the spin chuck;
a washing liquid supply mechanism for supplying a washing liquid through the brushing section onto the washing surface of the substrate;
a pressure control mechanism for controlling a pressing force of the scrubbing member against the washing surface of the substrate; and
a moving means for moving the scrubbing member relative to the substrate in a radial direction of the substrate,
wherein the scrubbing member includes:
an abutting section which is brought into contact with the washing surface of the substrate; and
a non-contact peripheral section positioned about the abutting section and formed not to contact the washing surface of the substrate when the abutting section is in contact with the washing surface of the substrate.
If the non-contact peripheral section of the scrubbing member is curved in three dimensional directions to form a hemispherical configuration, the pressure concentration can be suppressed. Therefore, even if an arm supporting, for example, a washing member is inclined, the contact pressure can be made uniform over the entire contact region between the washing member and the washing surface of the substrate.
It is desirable for the sponge portion of the scrubbing member to be formed of a foamed polyvinyl alcohol (PVA) or a foamed polyvinyl formal (PVF).
In the present invention, the supply pressure of the washing liquid is variable, making it possible to control the swelling degree of the washing member by varying the supply pressure and, thus, to control the contact pressure of the washing member against the substrate.
According to another aspect of the present invention, there is provided a method of washing a substrate, comprising the steps of (a) arranging in a waiting section a scrubbing member including an abutting section which is brought into contact with a washing surface of the substrate, and a non-contact peripheral section positioned about the abutting section and formed not to contact the washing surface of the substrate when the abutting section is in contact with the washing surface of the substrate, the waiting section being positioned outside of a spin chuck and provided with a cleaner member for removing stains from the scrubbing member to cleanse the scrubbing member, (b) mounting a substrate on the spin chuck, (c) rotating the substrate together with the spin chuck, (d) moving the scrubbing member from the waiting section to an operating section near the substrate to permit the abutting section of the scrubbing member to be brought into contact with a washing surface of the rotating substrate, and supplying a washing liquid through the scrubbing member. onto the washing surface of the substrate, (e) moving the scrubbing member relative to the substrate in a radial direction of the substrate while the abutting section of the scrubbing member is in contact with the washing surface of the substrate so as to have the washing surface of the substrate scrubbed with the abutting section, and (f) bringing the scrubbing member after the scrubb
Kubota Minoru
Miyamoto Ken'ichi
Swanson Walter
Tanaka Hideya
Markoff Alexander
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Tokyo Electron Limited
LandOfFree
Apparatus and method for washing substrate does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for washing substrate, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for washing substrate will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2820760