WO2018082905A1

WO2018082905A1 - Cleaning device for rinsing dispensing nozzles

Info

Publication number: WO2018082905A1
Application number: PCT/EP2017/076282
Authority: WO
Inventors: Wolfgang Kroeber; Arlindo Baptista FONSECA
Original assignee: solar-semi GmbH
Priority date: 2016-11-04
Filing date: 2017-10-16
Publication date: 2018-05-11
Also published as: EP3318334A1

Abstract

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.

Description

CLEANING DEVICE FOR RINSING DISPENSING NOZZLES

Field of the Invention

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

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.

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.

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. 6418946 Bl 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.

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.

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.

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.

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.

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

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.

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.

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.

In one embodiment, the or each nozzle drain outlet is provided as an opening in the solvent bath.

In one embodiment, the or each nozzle drain outlet has an opening which is raised from a bottom level of the solvent bath.

In one embodiment, said nozzle drain outlet is an overflow opening to the solvent bath.

In one embodiment, the cleaning device comprises a nitrogen gas inlet to the chamber.

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.

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.

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.

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.

In one embodiment, the or each nozzles drain outlet is sealed using a u-shape syphon connected to the chamber. In one embodiment, a nozzle present in the inlet is suspended above an upper surface of a solvent present in the solvent bath.

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.

In one embodiment, the liquid dispensing system comprises a dispensing liquid supply connected to said nozzles by means of a valves subsystem.

In one embodiment, the nozzles arm holds the nozzles by means of clamps.

In one embodiment, the liquid dispensing system comprises a spin table at said liquid dispensing position. Brief description of the figures

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

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. 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.

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.

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.

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.

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.

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.

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.

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. 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.

Valve VI 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.

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 VI 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.

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.

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.

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. 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.

Claims

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.