JPH0938590A - Method and apparatus for cleaning - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning method in which an article to be cleaned can always be cleaned properly and efficiently, and an apparatus for the method. SOLUTION: This apparatus is equipped with a cleaning tank 1 in which a container 100 to be cleaned is arranged at a prescribed position to be immersed in a chemical liquid 2, a projector 3 which is placed close to the cleaning tank 1 so as to form a prescribed optical path 5 passing through the container 100, a light receiver 4 which is arranged to receive light emitted from the projector 3 at a position close to the cleaning tank 1 through the optical path 5, and a light quantity detection means which detects the quantity of light received by the light receiver 4. The degree of cleaning of the container 100 is detected by the change in the quantity of received light in the light receiver 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning apparatus and a cleaning method for a reaction container used in a film forming apparatus for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art In a film forming apparatus of this type or a heating apparatus, particularly a so-called hot wall type CVD apparatus, as the film forming reaction proceeds in a reaction container made of quartz, the reaction container, etc. A film containing a metal halide or the like is deposited on the surface of the quartz jig. Then, as it is, particles are generated due to degassing or peeling from the deposited film. In order to prevent this, when the deposited amount of the deposited film reaches a certain level with the quartz jig, the deposited film is removed.

In order to remove such a deposited film, conventionally, for example, a quartz jig on which the deposited film is deposited is removed from the apparatus, immersed in a chemical solution, and cleaned by etching. In this case, the required constant cleaning time was set according to the thickness of the deposited film to be removed. Then, after the cleaning is completed, it is visually confirmed whether or not the cleaning is completed.

[0004]

However, in such a conventional cleaning apparatus or cleaning method, cleaning was performed for a certain period of time depending on the thickness of the deposited film to be removed. It was not always possible to determine the optimum cleaning time with a uniform etch rate due to differences in surface conditions and variations. Therefore, the final confirmation of the completion of cleaning must be done visually.
In addition, not only is it difficult to automate such visual confirmation work, but the judgment criteria for final confirmation are ambiguous, so it is necessary to set a long cleaning time to cover this, so it is necessary. Problems such as the above-mentioned work time are required.

Therefore, it is an object of the present invention to provide a cleaning apparatus and a cleaning method capable of always properly and efficiently cleaning an object to be cleaned of this kind.

[0006]

A cleaning device according to the present invention is a device for cleaning a translucent object to be cleaned with a chemical solution, which is designed to pass through the object to be cleaned immersed in the chemical solution. An optical path is formed, the cleaning target is cleaned with the chemical solution, and the cleaning level is detected based on a change in the amount of transmitted light of the cleaning target.

Further, the cleaning apparatus according to the present invention includes a cleaning tank in which a container to be cleaned is placed and accommodated at a predetermined position, and the container to be cleaned is immersed in a chemical solution, and a predetermined optical path passing through the container to be cleaned. And a light receiver disposed so as to receive light emitted from the projector at a position close to the cleaning tank through the optical path. And a light amount detection means for detecting the amount of light received by the light receiver, and the degree of cleaning of the container to be cleaned is detected by a change in the amount of light received by the light receiver.

Further, in the cleaning apparatus according to the present invention, the light projecting device and the light receiving device are arranged on both sides of a predetermined portion of the container to be cleaned with the predetermined region sandwiched therebetween. Alternatively, in the cleaning apparatus according to the present invention, at least one reflecting mirror is provided between the light projector and the light receiver, and an optical path that passes through the container to be cleaned at least twice is formed.

Further, the cleaning method according to the present invention is a method for cleaning a transparent object to be cleaned with a chemical solution,
A step of immersing the article to be cleaned in the chemical solution and holding the article to be cleaned in a predetermined position; a step of forming a predetermined optical path through the article to be cleaned immersed in the chemical solution; Receiving light that has passed through the object to be cleaned inserted in, and detecting a change in the amount of received light, the degree of cleaning of the object to be cleaned is determined by whether or not the amount of received light reaches a constant value. Is detected.

[0010]

According to the present invention, for example, when a particularly transparent container to be cleaned (quartz jig which is a reaction container) is washed with a chemical solution, the quartz jig is preferably supported by a predetermined washing basket. And is immersed in the chemical solution in the cleaning tank. Then, when the quartz jig is inserted into the optical path formed between the projector and the receiver,
The light emitted from the light projector passes through the quartz jig and is received by the light receiver. In this case, the amount of light received by the light receiver changes depending on the amount (film thickness) of the deposited film deposited on the quartz jig. For example, the larger the deposition amount, the smaller the received light amount. The amount of received light increases as the cleaning with the chemical progresses, and when the deposited film is completely removed, the amount of received light of the light receiver becomes a substantially constant value. Therefore, the completion of cleaning of the quartz jig can be confirmed by checking whether or not the received light amount reaches a constant value.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of a cleaning apparatus and a cleaning method according to the present invention will be described below with reference to FIG.
The cleaning apparatus according to the present embodiment has a cleaning tank 1 in which a quartz jig 100, which is a container to be cleaned, is placed and housed in a predetermined position, and the quartz jig 100 is immersed in a chemical solution 2, and a quartz jig 1.
So that the optical path 5 passing through 00 is formed, the projector 3 arranged at the closest position to the cleaning tank and the light emitted from the projector 3 are received at the closest position to the cleaning tank 1 via the optical path 5. The light receiver 4 is provided.

The quartz jig 100 has, for example, a substantially cylindrical shape with one end open as shown in the figure, and is used for forming a film of silicon nitride. In this case, 10% hydrogen fluoride (HF) is specifically selected as the chemical liquid 2 to be filled in the cleaning tank 1. When the quartz jig 100 is immersed in the chemical solution 2, the quartz jig 100 is supported by a lifter 6 that moves up and down, and the lifter 6 is appropriately moved up and down.

The light projector 3 includes a light source (not shown) (which may be, for example, a large LED) and emits light toward the quartz jig 100 when the light source is turned on. The light receiver 4 is arranged at a position facing the light projector 3 with the quartz jig 100 interposed therebetween as in the illustrated example, and is a light amount detection means (not shown) for detecting the received light amount (for example, a photodiode or a phototransistor). Good). Although the optical path 5 is formed so as to pass through substantially the center of the quartz jig 100 in this illustrated example, the quartz jig 100 is cleaned during cleaning.
It is preferable to set the optical path so as to pass through the portion where it is most difficult to remove the deposited film in.

In the cleaning apparatus having the above structure, the quartz jig 100 is transferred to the lifter 6 and the lifter 6 is lowered from above the cleaning tank 1, so that the quartz jig 100 is immersed in the chemical solution 2 in the cleaning tank 1. Be immersed in. The silicon nitride film deposited on the quartz jig 100 is gradually dissolved by the chemical liquid 2. At this time, the quartz jig 100 includes the light projector 3 and the light receiver 4.
The light, which is inserted in the optical path 5 formed between them and is emitted from the light projector 3, is received by the light receiver 4 after passing through the quartz jig 100.

If the silicon nitride film remains on the quartz jig 100, the transparency of the quartz jig 100 will be reduced due to the silicon nitride film. That is, during the melting of the silicon nitride film, the amount of light received by the light receiver 4 changes according to the residual film of silicon nitride deposited on the quartz jig 100. The amount of received light increases as the cleaning with the chemical liquid 2 progresses, and when the silicon nitride film is completely removed, the amount of received light of the light receiver 4 becomes a substantially constant value. Therefore, when the amount of received light becomes a constant value, it is possible to determine the end of cleaning of at least the portion of the quartz jig 100 arranged in the optical path 5.

In the above case, in the quartz jig 100, a plurality of portions or points through which the optical path 5 passes may be set, and the cleaning degree may be confirmed at a plurality of portions. In this case, the optical path 5 is relatively moved along the longitudinal direction of the quartz jig 100, and changes in the amount of light received by the light receiver 4 are detected at a plurality of points on the quartz jig 100.

FIG. 2 shows a second embodiment of the cleaning device according to the present invention. In this embodiment, the projector 3
Further, a plurality of reflecting mirrors 7 to 13 are attached between the light receiving device 4 and the light receiving device 4, and in this case, the optical path 5 passing through the quartz jig 100 eight times is formed. Each reflecting mirror 7 ,. . , 12, 13 are alternately arranged on both sides of the quartz jig 100 as in the illustrated example, and the optical path 5 is formed in a zigzag shape. When arranging the reflecting mirrors 7 to 13,
A transparent case 7a, which is made of quartz glass or a transparent acrylic material and has a small amount of corrosion resistance and metal contamination ,. . , 12a, 13
It is sealed in a so as to protect the reflecting mirrors 7 to 13 from the chemical solution 2. In order to prevent the optical path 5 from interfering with the lifter 6 and the like, for example, as shown in this illustrated example, the reflecting mirror 9
Preferably, 11 and 11 are arranged inside the lifter 6.

According to the second embodiment, the cleaning degree of the quartz jig 100 can be evenly detected by making the optical path 5 pass through the quartz jig 100 a plurality of times. The entire cleaning state can be accurately grasped.
By further adding the reflecting mirrors 7 to 13 and increasing the number of times that the optical path 5 formed by them passes through the quartz jig 100, the cleaning degree can be confirmed more accurately.

In the above embodiment, the quartz jig 1
No. 00 reflected light amount, color change, or the like is used, and the change is estimated by the image processing by the image processing apparatus to detect the change, and the cleaning is estimated. It can also be configured to detect the condition. Although the quartz jig 100, which is a reaction container, has been described as an example of the object to be cleaned, it can be effectively applied to other containers.

[0020]

As described above, according to the present invention, it is possible to more accurately confirm the cleaning state of this type of object to be cleaned by optically detecting the cleaning level without visual inspection. You can In addition, the criteria for final confirmation of the cleaning degree can be clarified, and the cleaning state can be accurately grasped at all times, and the cleaning degree can be detected at the same time while performing the cleaning process, so extremely efficient work can be realized. It has the advantage that it can be done.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a first embodiment of a cleaning device according to the present invention.

FIG. 2 is a diagram showing an overall configuration of a cleaning device according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Cleaning Tank 2 Chemical Solution 3 Emitter 4 Light Receiver 5 Optical Path 6 Lifter 7, 8, 9, 10, 11, 11, 12, 13 Reflector 100 Quartz Jig

Claims (5)

[Claims] 1. An apparatus for cleaning a translucent object to be cleaned with a chemical solution, wherein a predetermined optical path is formed so as to pass through the object to be cleaned immersed in the chemical solution, and the object to be cleaned is the chemical solution. A cleaning apparatus for cleaning an object and detecting the degree of cleaning based on a change in the amount of transmitted light of the object to be cleaned. 2. A container to be cleaned is placed and housed in a predetermined position,
A cleaning tank in which the container to be cleaned is immersed in a chemical solution, a projector disposed near the cleaning tank so as to form a predetermined optical path through the container to be cleaned, and irradiation from the projector And a light quantity detector for detecting the quantity of light received by the light receiver, and a light quantity detector for detecting the quantity of light received by the light receiver. A cleaning device, wherein the cleaning degree of the container to be cleaned is detected by a change in the amount of received light in the container. 3. The cleaning apparatus according to claim 2, wherein the light projector and the light receiver are arranged on both sides of a predetermined portion of the container to be cleaned with the predetermined portion sandwiched therebetween. 4. The cleaning apparatus according to claim 2, wherein at least one reflecting mirror is provided between the light projector and the light receiver, and an optical path that passes through the container to be cleaned at least twice is formed. 5. A method for cleaning a translucent article to be cleaned with a chemical solution, the method comprising the steps of immersing the article to be cleaned in the chemical solution and holding the article to be cleaned in a predetermined position, A step of forming a predetermined optical path so as to pass through the article to be cleaned immersed in a chemical solution, and receiving light transmitted through the article to be cleaned inserted into the optical path,
A step of detecting a change in the amount of received light, wherein the cleaning degree of the object to be cleaned is detected depending on whether or not the amount of received light has reached a constant value.