Field of the Invention
[0001] The invention relates generally to the field of liquid dispensing systems, such as
spin coating systems, for use in semiconductor, MEMS, Piezo MEMS, FPD and related
industries. More particularly, solutions are provided related to a cleaning device
for handling dispensing nozzles, such as for rinsing, pre-dispensing and protecting
them against the environment.
Background
[0002] Liquid dispensing systems, including spin coating systems, are well known in the
semiconductor industry and other related industries, and have been used for many decades.
Such systems and devices comprise a nozzle or a set of nozzles, which may be stacked
on an arm for the purpose of placing the nozzles at various position. For instance,
the nozzles may be movable between a spin table for dispensing coating material, and
a parking or standby position, herein also commonly referred to as a resting position.
[0003] Some coating materials, e.g. PZT Sol-Gel, are very sensitive to environmental moisture
and dryness. Such atmospheres may in practice result in particle creation around the
nozzle and will have a negative impact on the coating quality, which leads to layer
defects induced by these particles. For these purposes, means are required for cleaning
such nozzles.
[0004] Fig. 1 is a schematic plane view of prior art type system and device. Nozzles 1,
exemplified by three separate conduits in the drawing, may be placed in a resting
position, where an underlying drip pan 2 is arranged. This drip pan 2 has a drain-syphon
device 3 to keep a cleaning solvent in the drip pan 2 at or below a predetermined
level 4. The drip pan 2 is open in order to keep the nozzles 1 surrounded by the same
solvent vapor and to have the possibility of pre-dispensing coating material from
the nozzles into the drip pan. This results into some contamination of the cleaning
solvent in the bath of the drip pan 2, which leads to the solvent having to be changed
more often. Further prior art devices related to this field of use are presented below.
[0005] 6418946 B1 discloses an apparatus for cleaning dried photoresist from dispensing
nozzle. This document discloses a cleaning method in which a tip of a dispensing nozzle
inserted in a nozzle base under the nozzle, and a catch pan is positioned beneath
the nozzle base. A cleaning solvent dispensing needle inserted through an opening
in the catch pan facing the dispensing nozzle tip sprays the cleaning solvent onto
the dispensing nozzle tip. Thereafter the cleaning solvent drained out.
[0006] US20130319470 discloses a device for nozzle cleaning, which is capable of uniformly cleaning a
nozzle from the front end to the upper part of the nozzle, but does not protect the
nozzle from contamination and air moisture.
[0007] US20140283878 discloses a nozzle cleaning unit, which comprises a gas supply unit and a regulator,
and an ejection hole that opens in a ring shape to an inner wall surface of an insertion
part into which the nozzle is inserted. The gas regulator reduces the pressure of
an atmosphere of the insertion part on a side opposite a side in which the nozzle
inserted.
[0008] US20160016208 discloses a nozzle cleaning device and method. The device has a cavity and a sealed
chamber, comprising a cleaning tank, motor, driving bearings connected to the motor,
rotation shafts connected to the driving bearings. A cleaning block is fitted on the
rotation shafts disposed above carrier portion. The device further includes heating
means, and an ultra-sonic wave device.
[0009] US5958517 discloses a system and a method for cleaning nozzle delivery spin-on-glass to a substrate.
An open cavity filled through the nozzle for cleaning it in a way that the nozzle
stays immersed in the cleaning solvent. The cavity drains after a while through tiny
holes when the feed stops. This system is not sealed, and not protected from environment
contamination.
[0010] US8764912 B2 discloses a method and device for cleaning nozzle, but does not keep a rested nozzle
protected from environmental contamination and from drying.
Summary of the invention
[0011] In order to prevent nozzles from particle creation and dryness, three levels of protection
are beneficial when the nozzles are in their parking or in standby mode in a resting
position. These include:
- Keeping the nozzles in a solvent-saturated atmosphere in moisture-free environment.
- Rinsing the nozzles externally after use, in the parking or standby mode.
- Rinsing the nozzles internally and preferably keeping cleaning solvent inside the
nozzles when they are not in use for long periods, e.g. in a tool standby mode.
[0012] In view of the state of the art and the quality of the result of using such devices,
there is a need for improvement in the art of nozzle cleaning for liquid dispensing
systems. These objects are targeted and solved by the present invention.
[0013] According to one aspect, a cleaning device for rinsing dispensing nozzles is provided,
comprising a sealed protection chamber; a solvent bath provided to maintain a solvent-saturated
atmosphere in the chamber; a sealed inlet for introducing one or more dispensing nozzles
into the chamber; a solvent supply system connected to lead a cleaning solvent to
rinse a nozzle present in the inlet; and a nozzle drain outlet arranged below the
or each inlet, such that cleaning solvent from a nozzle falls into said nozzle drain
outlet.
[0014] In one embodiment, the or each nozzle drain outlet is provided as an opening in the
solvent bath.
[0015] In one embodiment, the or each nozzle drain outlet has an opening which is raised
from a bottom level of the solvent bath.
[0016] In one embodiment, said nozzle drain outlet is an overflow opening to the solvent
bath.
[0017] In one embodiment, the cleaning device comprises a nitrogen gas inlet to the chamber.
[0018] In one embodiment, the solvent supply system includes a first channel connection
to the or each inlet for rinsing an exterior portion of a nozzle present in the inlet.
[0019] In one embodiment, the solvent supply system includes a second connection to a dispensing
channel of a nozzle, for rinsing an interior portion of a nozzle present in the inlet.
[0020] In one embodiment, the solvent supply system includes a valves subsystem connectable
to selectably supply a solvent or a dispensing fluid to the or each nozzle.
[0021] In one embodiment, a plurality of nozzle inlets are provided over each one separate
nozzle drain, which nozzle drains are merged together to form a common nozzles drain
outlet.
[0022] In one embodiment, the or each nozzles drain outlet is sealed using a u-shape syphon
connected to the chamber.
[0023] In one embodiment, a nozzle present in the inlet is suspended above an upper surface
of a solvent present in the solvent bath.
[0024] According to a second aspect, a liquid dispensing system is provided, comprising
one or more dispensing nozzles; a nozzles arm holding the nozzles, controllable to
move the nozzles between a liquid dispensing position and a resting position; and
a cleaning device including any of the features outlined above, wherein the nozzle
arm is configured to introduce the nozzles into inlets of said cleaning device at
said resting position.
[0025] In one embodiment, the liquid dispensing system comprises a dispensing liquid supply
connected to said nozzles by means of a valves subsystem.
[0026] In one embodiment, the nozzles arm holds the nozzles by means of clamps.
[0027] In one embodiment, the liquid dispensing system comprises a spin table at said liquid
dispensing position.
Brief description of the figures
[0028] Various non-limiting embodiments will be described below with reference made to the
accompanying drawings, in which
Fig.1 is a schematic drawing of the prior art that shows a nozzle cleaning device;
Fig. 2 is the outer look of an embodiment of a nozzle cleaning device according to
the invention;
Fig. 3 shows a front view cross section of the device of Fig. 2;
Fig. 4 shows a side view cross section of the device of Fig. 2; and
Fig. 5 schematically illustrates a valves subsystem for supplying fluid to the nozzle
cleaning device.
Detailed description of the invention
[0029] The invention will now be described more fully hereinafter with reference to the
accompanying drawings, in which embodiments of the invention are shown. This invention
may, however, be embodied in many different forms and should not be construed as limited
to the embodiments set forth herein; rather, these embodiments are provided so that
this disclosure will be thorough and complete, and will fully convey the scope of
the invention to those skilled in the art.
[0030] It will be understood that, when an element is referred to as being "connected" to
another element, it can be directly connected to the other element or intervening
elements may be present. In contrast, when an element is referred to as being "directly
connected" to another element, there are no intervening elements present. Like numbers
refer to like elements throughout. Well-known functions or constructions may not be
described in detail for brevity and/or clarity. Unless otherwise defined, all terms,
including technical and scientific terms, used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this invention belongs.
[0031] Embodiments of the invention are described herein with reference to schematic illustrations
of various embodiments of the invention. As such, variations from the shapes and relative
sizes of the illustrations as a result, for example, of manufacturing techniques and/or
tolerances, are to be expected. Thus, embodiments of the invention should not be construed
as limited to the particular shapes and relative sizes of regions illustrated herein
but are to include deviations in shapes and/or relative sizes that result, for example,
from different operational constraints and/or from manufacturing constraints. Thus,
the elements illustrated in the figures are schematic in nature and their shapes are
not intended to illustrate the actual shape of a region of a device and are not intended
to limit the scope of the invention.
[0032] The present invention discloses a cleaning device for rinsing dispensing nozzles,
comprising a protection chamber 10, which is sealed against external environment to
prevent nozzles 6 from drying and from contacting the air moisture. The cleaning device
is further configured to conveniently clean nozzles both internally and externally.
Preventing the nozzles 6 from particle creation, contamination and drying is a principal
object of the invention. In order to satisfy these conditions, it is desirable to
rinse the nozzles 6, preferably both externally and internally after each use. When
nozzles are not in use for long periods, i.e. in parking or standby modes, a cleaning
solvent 52 is kept inside the nozzles 6, and the nozzles 6 are held in a sealed environment
with a cleaning solvent saturated atmosphere, preventing the nozzles tips from drying
and getting in contact with air moisture. Dispensing materials 51 which the nozzles
6 are configured to dispense may be coating materials, for example but not limited
to photoresist or PZT Sol Gel. The cleaning solvent 52 type is preferably selected
depends on the dispensing material 51 the nozzles 6 have been used with. The configuration
and function of the cleaning device is as such not dependent on the type of dispensing
material 51 or cleaning solvent 52. The sealed protection chamber 10 is static in
its operation and function and has no electrical or mechanical movements inside.
[0033] Fig. 2 Shows an exterior view of an embodiment of the cleaning device, which may
be disposed at a resting position of a liquid dispensing system. The cleaning device
comprises a sealed protection chamber 10, into which a nozzle or plurality of nozzles
6 may be introduced for cleaning. Such nozzles 6 may be carried on a nozzle arm 5,
on which they may be suspended by means of nozzles clamps 7. Such a nozzle arm 5 may
act as a hand to move the nozzles 6 from an operative liquid dispensing position,
e.g. a spin coating area, to a resting position where the cleaning device is provided.
[0034] As visible in Figs 3 and 4, the cleaning device has one or more sealed nozzle openings
8 for introducing one or more nozzles 6. The nozzle arm 5 may also be configured to
insert the nozzles 6 through the sealed upper nozzle opening 8 into separate nozzles
rinse channels or tubes. In one embodiment, each such rinse channel has the ability
to be supplied with rinse solvent, such as cleaning solvent 52, by means of supply
channels 15. Below the nozzle opening 8 and nozzles rinse channel, a cleaning solvent
bath 13 is provided in the sealed protection chamber 10. A solvent 52 present in the
bath 13 has an upper level given by the overflow opening 111 of a nozzles drain 11.
The cleaning solvent 52 in the sealed protection chamber 10 creates a saturated atmosphere,
maintain also thanks to the sealing of inlets 8, around the nozzles 6 to prevent coating
material in the nozzles 6 from drying. After dispensing coating material, nozzles
6 may be introduced into the inlets 8 of the cleaning device, where they are rinsed
by means of a cleaning solvent, which is controlled to flow through nozzles rinse
supply channels 15 to the nozzles rinse channels so as to rinse the nozzles 6 present
therein, and from there down through the nozzles drain outlet 11.
[0035] Each nozzle 6 preferably has separate drain outlet underneath the nozzle, which merge
to form a common nozzles drain outlet 11, preferably also using a u-shape syphon outside
of the whole cleaning device (see schematic representation in Fig. 5). The nozzles
6 are normally rinsed after each or several usages by means of cleaning solvent 52.
The nozzles 6 are not immersed into the solvent bath 13 inside the sealed protection
chamber 10, and therefore the solvent bath will not be contaminated by the coating
material. In addition, the nozzles 6 introduced in the nozzles rinse channels at the
inlets 8 are positioned such that the nozzles drain outlet 11 is arranged below the
or each inlet 8, such that cleaning solvent applied onto a nozzle falls into said
nozzle drain outlet. Preferably each nozzle 6 introduced into an inlet 8 is positioned
above a separate drain outlet underneath the nozzle 6, into which rinsed cleaning
solvent is allowed to drip or flow, as can be gathered from Fig. 3.
[0036] In one embodiment, a Nitrogen gas inlet 12 is connected to the sealed protection
chamber 10 to form a cushion to blow out environmental air and preventing air from
entering the sealed protection chamber 10, thus keeping the chamber 10 moisture free
when the nozzles 6 are pulled out from the chamber 10 to perform a new order to dispense
coating material 51. A solvent inlet 14 is preferably provided for filling the bath
13 at the lower part of the protection chamber 10 with solvent 52, so as to keep nozzles
6 under a solvent-saturated atmosphere to prevent nozzle tip drying. A coating material
51 inlet (not shown) is also connected to the nozzles from the upper side.
[0037] Fig. 5 shows a valves subsystem for the cleaning device according to an embodiment.
The valves subsystem is configured and controlled to control the flow of the cleaning
solvent 52 and coating material 51 to the nozzles 6 and the sealed protection chamber
10. The valves are opens and closes on request, and may be operated by an automated
cleaning control system. The valves subsystem controls cleaning solvent supply 52
to nozzles rinse channel connections 15, see also Fig. 4, where circular cross-sections
of front and back channels 15 are indicated, provided at each nozzle inlet 8 for cleaning
each introduced nozzle 6. The cleaning solvent connections 15 are individually connected
to provide cleaning solvent to rinse an external side of the nozzles 6 when present
in the nozzle rinse channels at the inlet 8. In one embodiment, this is done by opening
and closing the cleaning solvent inlet valve V2 in Fig. 5. After rinsing the external
side of the nozzles 6, the cleaning solvent drained out to the common drainage 11,
as also seen in Figs 3 and 4, without getting in contact and contaminating the solvent
bath 13 inside the sealed protection chamber 10. The common drainage 11 is preferably
connected to a U-shaped tube 112, as seen in Fig. 5, which serves as syphon in order
to prevent external air from entering the sealed protection chamber 10 via nozzles
drain outlet 11, and keeps the level of the cleaning solvent in the chamber fixed
at all times.
[0038] The valves V2, V3, and V4 are selectably opened and closed to let cleaning solvent
52 pass through the nozzles rinse channels tubes 15, inside the nozzles 6, and to
top-up the solvent 52 of the bath 13 in the sealed protection chamber.
[0039] Valve V1 opens and closes to let dispensing material 51, such as a coating material,
pass to the nozzle 6 when a new order initiated to start e.g. spin coating.
[0040] To start rinsing of an internal side of the nozzle 6 from the dispensing material,
when the nozzle 6 is present in the cleaning device, valve V3 opens and closes to
let the cleaning solvent 52 pass through the nozzle inner side and drain the solvent
to the common drainage 11. This will remove the coating material from inside the nozzles
6 and keep it clean until the next order for e.g. spin coating. This internal rinse
is typically performed when a liquid dispensing system goes to standby mode, waiting
for the next order. The solvent 52 stays in the nozzle 6 until a new job order is
given to the liquid dispensing system. Before a new job is launched, valve V1 preferably
opens to perform a pre-dispense of the coating material while the nozzle is still
present in the cleaning device, to fill the nozzle with this material prior to start
the dispense on substrates. Since the nozzle drain 11 is present immediately under
the nozzle position in the cleaning device, such pre-dispensed material will not contaminate
the solvent in the bath 13.
[0041] To start to rinse the external side of the nozzle from the coating material, valve
V2 opens and closes to let the cleaning solvent pass to the channel connection 15
to clean the external side of the nozzle 6 and drain the solvent to the common drainage
11. This will remove the coating material from outside the nozzles and keeps it clean
until the next order for spin coating. This external rinse is freely programmable
and can be performed either after each material dispense or longer dispense iterations.
[0042] To rinse the solvent bath 13 from the inside the sealed protection chamber 10, valve
V4 opens and closes at a given time delay to rinse and fill-up the bath in the chamber.
The surplus solvent overflows at the rim of the nozzle drain and runs down into the
common drain 11. This operation is independent from the cleaning device's status,
whether it is in operation or in a parking or standby modes.
[0043] When there is no order for e.g. spin coating for some time, the system is preferably
controlled to maintain the nozzles parked inside the sealed protection chamber 10
protected from external environment and air moisture as well as the nozzles are kept
in a cleaning solvent saturated atmosphere preventing the nozzles tips from drying.
[0044] In a preferred embodiment, the sealed protection chamber 10 is firmly sealed and
static in its operation; i. e. there is no mechanical or electrical activity inside
the chamber before, during, or after the rinsing activity. In such an embodiment,
it is a sealed box with inlets and outlets for cleaning solvent and cleaning solvent
drainage, and preferably also inlets for dispensing material and Nitrogen gas.
1. A cleaning device for rinsing dispensing nozzles comprising
a sealed protection chamber (10);
a solvent bath (13) provided to maintain a solvent-saturated atmosphere in the chamber;
a sealed inlet (8) for introducing one or more dispensing nozzles (6) into the chamber;
a solvent supply system connected to lead a cleaning solvent to rinse a nozzle present
in the inlet; and
a nozzle drain outlet (11) arranged below the or each inlet, such that cleaning solvent
from a nozzle falls into said nozzle drain outlet.
2. The cleaning device of claim 1, wherein the or each nozzle drain outlet is provided
as an opening (111) in the solvent bath.
3. The cleaning device of claim 1 or 2, wherein the or each nozzle drain outlet has an
opening (111) which is raised from a bottom level of the solvent bath.
4. The cleaning device of any of the preceding claims, wherein said nozzle drain outlet
is an overflow opening to the solvent bath.
5. The cleaning device of any of the preceding claims, comprising a nitrogen gas inlet
(12) to the chamber.
6. The cleaning device of any of the preceding claims, wherein the solvent supply system
includes a first channel connection (15) to the or each inlet (8) for rinsing an exterior
portion of a nozzle present in the inlet.
7. The cleaning device of claim 6, wherein the solvent supply system includes a second
connection (16) to a dispensing channel of a nozzle, for rinsing an interior portion
of a nozzle present in the inlet.
8. The cleaning device of claim 6 or 7, wherein the solvent supply system includes a
valves subsystem connectable to selectably supply a solvent or a dispensing fluid
to the or each nozzle.
9. The cleaning device of any of the preceding claims, wherein a plurality of nozzle
inlets are provided over each one separate nozzle drain, which nozzle drains are merged
together to form a common nozzles drain outlet.
10. The cleaning device of any of the preceding claims, wherein the or each nozzles drain
outlet (11) is sealed using a u-shape syphon (112) connected to the chamber.
11. The cleaning device of any of the preceding claims, wherein a nozzle present in the
inlet is suspended above an upper surface of a solvent present in the solvent bath.
12. A liquid dispensing system comprising
one or more dispensing nozzles (6);
a nozzles arm (5) holding the nozzles, controllable to move the nozzles between a
liquid dispensing position and a resting position; and
a cleaning device of any of the preceding claims, wherein the nozzle arm is configured
to introduce the nozzles into inlets (8) of said cleaning device at said resting position.
13. The liquid dispensing system of claim 12, comprising a dispensing liquid supply (51)
connected to said nozzles by means of a valves subsystem.
14. The liquid dispensing system of claim 12 or 13, wherein the nozzles arm (5) holds
the nozzles (6) by means of clamps (7).
15. The liquid dispensing system of any of claims 12-14, comprising a spin table at said
liquid dispensing position.