JPH10189526A - Method and apparatus for cleaning of reticle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning method for a reticle, in which a cleaning effect is high. SOLUTION: A reticle cleaning method refers to a cleaning method for a reticle for photolithography which is applied when a semiconductor device is manufactured. Instead of a brush scribing and cleaning operation in conventional cases, pure water is jetted to both faces of the reticle in a first reticle cleaning part 12, and the reticle is immersed in a surface-active agent solution in a surface-active agent treatment part 14. Then, ammonia water and pure water are jetted to both faces of the reticle in a second reticle cleaning part 16, and the reticle is cleaned. In addition, in the same manner as in conventional cases, the reticle is cleaned ultrasonically by executing a pure-water ultrasonic cleaning operation in an ultrasonic cleaning part 18, and the reticle is dried by IPA(isopropyl alcohol) vapor in an IPA drying part 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a reticle cleaning method and apparatus, and more particularly to a reticle cleaning method and apparatus having a high cleaning effect.

[0002]

2. Description of the Related Art If foreign matter such as particles adheres to a reticle used in photolithography, an accurate pattern cannot be transferred onto a substrate. Therefore, conventionally, the reticle is washed before or after the exposure, or by temporarily stopping the exposure. Conventionally, cleaning of the reticle has been performed by the brush / scribe cleaning apparatus 50 shown in FIG. 7, the ultrasonic cleaning apparatus 52 shown in FIG. 8, and the IPA drying apparatus 54 shown in FIG. (1) First, a brush scribe cleaning step is performed using the brush scribe cleaning device 50. While discharging the ammonia water from the lower nozzle 57, the brush 5
8 is rotated and brought into contact with the reticle R for cleaning. When the reticle R is lifted, pure water is spouted from the upper nozzle 56 toward the reticle R to wash away foreign substances attached to the reticle R. (2) Next, an ultrasonic cleaning step is performed using the ultrasonic cleaning device 52. The reticle R is immersed in the cleaning tank 60 containing pure water, and the reticle R is irradiated with ultrasonic waves from the ultrasonic generator 62 for cleaning. While pulling up the washed reticle R from the pure water, the pure water is supplied from the nozzle 63 to the reticle R.
To remove foreign matter on the reticle R. (3) Finally, an IPA drying step is performed using the IPA drying device 54. IPA (isopropyl alcohol) is accommodated in the IPA tank 66 and heated by the heater 64 to form the IPA.
A vapor is generated, the reticle R is put into the IPA vapor, the IPA vapor is condensed on the reticle R, and the condensed IPA replaces the water adhering to the reticle R. While replacing, reticle R
Is heated to the boiling point of IPA, and condensed IPA is evaporated to dryness. After cleaning, a particle inspection is performed. If the particles have not been removed to a satisfactory degree, re-cleaning is required.

[0003]

However, in the conventional cleaning method described above, the cleaning effect of the reticle is low, and it is often necessary to reclean the particles because the particles remain in the particle inspection after the cleaning. Had occurred. By the way, as the miniaturization of the semiconductor device progresses, particles attached to the reticle exert a significant influence on the patterning, and it is increasingly difficult to perform accurate patterning. Therefore, development of a reticle cleaning method having a high cleaning effect capable of coping with miniaturization of semiconductor devices is required.

[0004] From the above situation, the object of the present invention is to
An object of the present invention is to provide a reticle cleaning method having a high cleaning effect.

[0005]

Means for Solving the Problems The present inventor has investigated the cause of the low cleaning effect in the conventional reticle cleaning, and has found the following facts. That is, in the conventional method, since the brush scribe cleaning is performed, dust attached to the brush at the time of the previous cleaning adheres to the next reticle to be cleaned again, and as a result, defective cleaning of the reticle occurs. It turns out. If you change the brush every time you clean the reticle,
Such cleaning failure can be prevented, but replacement requires time and labor and requires a new brush. This increases the cost of cleaning the reticle and is not practical. Therefore, the inventor decided to develop a cleaning method that does not require brush scribe cleaning, and after repeating experiments,
The present invention has been completed.

In order to achieve the above object, a method of cleaning a reticle according to the present invention is a method of cleaning a reticle for photolithography applied when manufacturing a semiconductor device. (2) a step of immersing the reticle in a surfactant solution, (3) a step of washing by spraying a cleaning liquid and then pure water on the reticle, and (4) a step of immersing the reticle in pure water. It is characterized by comprising a step of immersing the reticle to perform ultrasonic cleaning, and (5) a drying step by IPA.

In the present invention, in the step (1), a reticle is
Preferably, pure water is sprayed on both surfaces of the reticle to wash and remove foreign substances attached to the reticle surface, for example, particles having a relatively large particle size. Next, in the step (2), the reticle is immersed in a surfactant solution, and relatively fine foreign matter adhering to the reticle surface is peeled off from the reticle surface by the cleaning action of the surfactant, and is removed in the next step (3). Make it easier. Subsequently, in step (3), a cleaning liquid, for example, ammonia water, and then pure water are sprayed onto the reticle surface to wash and remove the foreign matter peeled off in step (2). Ammonia water neutralizes the static electricity charged on the reticle, eliminates the electrostatic adsorption action, and facilitates the removal of the separated dust from the reticle surface. In the present invention, the combined operation of the steps (1), (2) and (3) allows the reticle to be cleaned instead of the conventional brush scribe cleaning. (4) The ultrasonic cleaning step and (5) the drying step by IPA are performed in the same manner as in the conventional case.

In the steps (1) and (3), the reticle can be more effectively cleaned by moving the reticle vertically between nozzles for injecting pure water or cleaning water. In the step (1), foreign matter on the reticle can be removed by injecting an inert gas with an ionizer instead of injecting pure water. The ionizer is
By neutralizing the static electricity charged on the reticle and eliminating the electrostatic adsorption action, the foreign matter on the reticle is easily peeled off, and then the foreign matter that is easily peeled off is blown off by an inert gas.

An apparatus for carrying out the reticle cleaning method according to the present invention comprises a first reticle having an arm for holding a reticle with a reticle surface substantially vertical, and a nozzle for jetting pure water to the reticle surface. A cleaning unit, a processing tank containing a surfactant solution, and an arm for holding the reticle and immersing the reticle in the surfactant solution of the processing tank. Vertically, an arm that holds the reticle, a cleaning water nozzle that injects cleaning water onto the reticle surface, and a pure water nozzle provided above the cleaning water nozzle to inject pure water, Second
A reticle cleaning unit, an ultrasonic cleaning tank that contains pure water, and has an ultrasonic generator and performs ultrasonic cleaning, and an arm that holds the reticle and is immersed in pure water in the ultrasonic cleaning tank. An ultrasonic cleaning unit, a drying chamber for receiving IPA, heating with a heater to generate IPA vapor, and drying the reticle with the IPA vapor, and an arm for holding the reticle and feeding the reticle into the drying chamber. , And an IPA drying unit.

[0010] Preferably, the holding arms of the first and second reticle cleaning sections allow the reticle to move up and down. Further, instead of the first reticle cleaning unit, an arm for holding the reticle, a nozzle for jetting clean air or a clean inert gas from above toward the reticle held by the arm, and an electrostatic charge for neutralizing the reticle surface charge An ionizer provided with a removing mechanism may be provided.

[0011]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings by way of examples. Embodiment of Reticle Cleaning Apparatus This embodiment is one of the embodiments of the reticle cleaning apparatus according to the present invention for carrying out the method of the present invention, and FIG. 1A is a block diagram showing the configuration of the reticle cleaning apparatus. FIG. 1 (b) is a process chart of the method of the present invention. 2 to 5 show details of each part of the apparatus. The present reticle cleaning apparatus 10 is an apparatus for cleaning a reticle for photolithography applied when manufacturing a semiconductor device. As shown in FIG. 1A, instead of a conventional brush scribe cleaning apparatus,
The first reticle cleaning unit 12, the surfactant processing unit 14, and the second reticle cleaning unit 16, and the ultrasonic cleaning unit 52 having the same configuration as the ultrasonic cleaning device 52 and the IPA drying device 54 used in the conventional reticle cleaning method. 18 and an IPA drying unit 20.

As shown in FIG. 2, the first reticle cleaning section 12 has nozzles 2 in upper and lower stages on both sides of a reticle R to be cleaned.
First cleaning tank 24 provided with 2A, B and nozzles 23A, B
And an arm 26 for holding the reticle R.
The nozzle 23 jets high-pressure pure water to clean the reticle surface and remove foreign matter. The nozzle 22 cleans the reticle surface with the nozzle 23, and then pulls up the reticle R,
Pure water is sprayed in a shower shape to clean the reticle R.
The arm 26 can hold both sides of the reticle R and hold the reticle surface in a substantially vertical direction toward the nozzles 22 and 23. More specifically, the arm 26 provided in the first reticle cleaning unit 12 is formed of a frame-like frame as shown in FIG. 3, and holds the reticle R in the frame, and can be moved up and down during cleaning. It is. Thereby, the first
The reticle cleaning unit 12 can perform cleaning with the nozzles 23 provided on both sides of the reticle R while holding the reticle R with the arm 26, and then with the nozzle 22.

As shown in FIG. 4, the surfactant processing section 14 has a processing tank 32 for storing a surfactant solution and a reticle R having the same configuration as the arm 26 of the first reticle cleaning section 12.
While holding the reticle R in the surfactant solution,
And an arm 34 that can move up and down. As shown in FIG. 5, the second reticle cleaning unit 16 includes nozzles 36A, B and
A second cleaning tank 38 provided with A and B, and an arm 40 that can move up and down while holding the reticle R with the same configuration as the arm 26 of the first reticle cleaning unit 12 are provided. Nozzle 37
Ejects high-pressure ammonia water toward the reticle surface, and the nozzle 36 ejects high-pressure pure water onto the reticle surface. The arm 40 can hold both side edges of the reticle R and hold the reticle surface almost vertically toward the nozzles 22A and 22B.

A pure water ultrasonic cleaning section 18 and an IPA drying section 2
The configuration of each of 0 is the same as that of the conventional device.

Embodiment of a Reticle Cleaning Method An embodiment of the method of the present invention using a reticle cleaning apparatus 10 shown in FIG. 1A will be described below. The method of the present invention is a method of cleaning a reticle for photolithography applied when manufacturing a semiconductor device. As shown in FIG. 1B, (1) cleaning is performed by spraying pure water on both surfaces of the reticle. A first cleaning step, (2) a surfactant treatment step in which the reticle is immersed in a surfactant solution, and (3) a second cleaning step in which a cleaning liquid and then pure water are sprayed onto both surfaces of the reticle to perform cleaning. (4) an ultrasonic cleaning step of performing ultrasonic cleaning with pure water;
(5) a drying step by IPA.

(1) First, a first cleaning step is performed using the first reticle cleaning unit 12 shown in FIG. Arm 26
Then, the reticle R is held and sent into the first cleaning tank 24, and high-pressure pure water is jetted from the nozzle 23 toward the reticle R. After the cleaning, when the reticle R is pulled up, pure water is ejected from the nozzle 22 in a shower shape to wash away foreign substances on the reticle surface. This makes it possible to wash and remove foreign substances attached to the reticle surface, for example, particles having a relatively large particle size. (2) Next, a surfactant treatment step is performed using the surfactant treatment unit 14 shown in FIG. The reticle R is held by the arm 34 and sent into the processing tank 32, and is moved up and down while being immersed in the surfactant solution. Thereby, the relatively fine foreign matter adhering to the reticle surface is peeled off from the reticle surface by the peeling action of the surfactant, and is easily removed in the next second cleaning step. (3) Further, a second cleaning step is performed using the second reticle cleaning unit 16 shown in FIG. The reticle R is held by the arm 40, sent into the second cleaning tank 38, and high-pressure ammonia water is injected from the lower nozzle 37 toward the reticle R. At the same time, high-pressure pure water is sprayed onto the reticle surface from the upper nozzle 36 to wash away the ammonia water and further remove and remove foreign matter. Ammonia water not only cleans the reticle surface, but also neutralizes static electricity charged on the reticle, quenching the electrostatic adsorption effect and (2) facilitating separation of dust removed in the surfactant treatment step. Fine foreign matter peeled from the reticle surface in the agent treatment process
Most are removed from the reticle surface.

Subsequently, using the ultrasonic cleaning apparatus 52 of FIG. 8 and the IPA drying apparatus of FIG. 9, the (4) ultrasonic cleaning step and the (5) IP
A drying step of A is performed. In this embodiment, (1),
By the combined action of the steps (2) and (3), the reticle can be cleaned instead of the conventional brush scribe cleaning.

Modification Example This modification example is a modification of the embodiment of the reticle cleaning apparatus according to the present invention, in which an ionizer is used instead of the first reticle cleaning section 12 of the reticle cleaning apparatus 10 of the embodiment. 42 are provided. As shown in FIG. 6, the ionizer 42 includes an ionizer tank 43 having an exhaust port 41 below.
In the tank 43, a static electricity removing mechanism 44 for neutralizing static electricity charged in the reticle R by air ions or nitrogen ions, and a nitrogen gas is ejected downward above and above the static electricity removing mechanism 44, respectively. Nitrogen gas ejection mechanism 45
And an arm (not shown) for holding the reticle. The nitrogen gas ejection mechanism 45 has a nitrogen gas ejection port 46 on its upper part, a filter section 48 for filtering and cleaning the nitrogen gas flowing out of the ejection port 46, and a nitrogen gas purified by the filter section 48, Nozzle 49 squirting toward
And The ionizer 42 removes the static electricity charged on the reticle R by the static electricity removing mechanism 44 to eliminate the electrostatic adsorption action, facilitates the separation of the foreign matter from the reticle surface, and then ejects the foreign matter that has been easily separated from the ejection nozzle 49.
Is removed from the reticle surface by nitrogen gas ejected from the reticle.
By using the ionizer 42 as in this modification, the amount of pure water used can be reduced.

[0019]

According to the method of the present invention, a step of injecting pure water into a reticle, a step of immersing the reticle in a surfactant solution, a step of washing the reticle with a surfactant solution, and then the step of cleaning the reticle with pure water And a step of washing by spraying on both sides of the substrate.
High dust removal effect of reticle. (2) As in the conventional method, dust attached to the brush during the previous cleaning adheres to the reticle to be cleaned next, and as a result, defective cleaning of the reticle does not occur. Further, the device according to the present invention realizes a device that efficiently performs the method of the present invention. Further, by using an ionizer instead of the pure water cleaning, the amount of pure water used can be reduced, and the reticle can be economically cleaned.

[Brief description of the drawings]

FIG. 1A is a block diagram showing the configuration of the present reticle cleaning apparatus, and FIG. 1B is a process diagram of the method of the present invention.

FIG. 2 is a schematic diagram illustrating a configuration of a first reticle cleaning unit.

FIG. 3 is a perspective view of the first reticle cleaning unit, showing details of an arm of the first reticle cleaning unit;

FIG. 4 is a schematic diagram illustrating a configuration of a surfactant processing unit.

FIG. 5 is a schematic diagram illustrating a configuration of a second reticle cleaning unit.

FIG. 6 is a schematic diagram showing a configuration of an ionizer.

FIG. 7 is a schematic diagram showing a configuration of a conventional brush scribe cleaning device.

FIG. 8 is a schematic diagram showing a configuration of an ultrasonic cleaning device.

FIG. 9 is a schematic diagram showing a configuration of an IPA drying device.

[Explanation of symbols]

Reference numeral 10 denotes an embodiment of a reticle cleaning apparatus, 12 denotes a first reticle cleaning section, 14 denotes a surfactant processing section, and 16 denotes a second.
Reticle cleaning unit, 18 Ultrasonic cleaning unit, 20 IP
A drying section, 22 ... nozzle, 23 ... nozzle, 24 ...
1st washing tank, 26 ... arm, 32 ... treatment tank, 34 ...
... Arm, 36 ... Nozzle, 37 ... Nozzle, 38 ...
Second washing tank, 40 ... arm, 42 ... ionizer,
43 ... Ionizer tank, 44 ... Static electricity removal mechanism, 4
Reference numeral 5: Nitrogen gas ejection mechanism, 46: Spout port, 48: Filter section, 49: Nozzle, 50: Brush scribe cleaning device, 52: Ultrasonic cleaning device, 54: IPA
Drying device, 56 nozzle, 57 nozzle, 58
Brush, 60 Cleaning tank, 62 Ultrasonic generator, 63
... Nozzle, 64 ... heater, 66 ... IPA tank.

Claims (7)

[Claims] 1. A method for cleaning a reticle for photolithography applied when manufacturing a semiconductor device, comprising:
(1) a step of injecting pure water into the reticle for cleaning;
(2) a step of immersing the reticle in the surfactant solution;
(3) a step of cleaning by spraying a cleaning liquid and then pure water onto a reticle; (4) a step of immersing the reticle in pure water to perform ultrasonic cleaning; and (5) a drying step by IPA. A method for cleaning a reticle, comprising: 2. The reticle cleaning method according to claim 1, wherein ammonia water is used as the cleaning liquid in the step (3). 3. The method according to claim 1, wherein in the steps (1) and (3), a reticle is arranged between nozzles for injecting pure water or cleaning water, and cleaning is performed while moving the reticle vertically. Item 3. The method for cleaning a reticle according to Item 1 or 2. 4. The method according to claim 1, wherein in the step (1), foreign matter is scattered from the reticle by injecting an inert gas while removing static electricity of the reticle by using an ionizer instead of jetting pure water. Or the reticle cleaning method according to 2. 5. A process for holding a reticle surface substantially vertical, an arm for holding the reticle, a nozzle for jetting pure water to the reticle surface, and a process for containing a surfactant solution. A surfactant treatment section of the reticle, comprising a tank and an arm for holding the reticle and immersing the reticle in a surfactant solution in the treatment tank; and an arm for holding the reticle with the reticle surface substantially vertical, and a reticle. A washing water nozzle that sprays washing water onto the surface,
And a second reticle cleaning unit including a pure water nozzle provided above the cleaning water nozzle for injecting pure water, and a supersonic generator that contains pure water and has an ultrasonic wave generating unit. An ultrasonic cleaning unit including an ultrasonic cleaning tank for performing ultrasonic cleaning, and an arm for holding a reticle and immersing it in pure water in the ultrasonic cleaning tank. A reticle cleaning apparatus, comprising: a drying chamber for generating the reticle and drying the reticle with IPA vapor; and an arm for holding the reticle and feeding the reticle into the drying chamber. 6. The reticle cleaning apparatus according to claim 5, wherein the holding arms of the first and second reticle cleaning units include a mechanism for holding the reticle and moving the reticle vertically. 7. An arm for holding a reticle, a static elimination mechanism for neutralizing static electricity charged on a reticle surface of the reticle held by the arm, and a static electricity removing mechanism instead of the first reticle cleaning unit. The reticle cleaning apparatus according to claim 5, further comprising an ionizer provided, and having a nozzle for injecting clean air or clean inert gas from above toward the reticle held by the arm.