JP3183043B2 - Vacuum processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum processing apparatus, and more particularly to a vacuum processing apparatus having a plurality of substrate cassettes installed in the atmosphere.

[0002]

2. Description of the Related Art In a vacuum processing apparatus such as a dry etching apparatus, a CVD apparatus or a sputtering apparatus, a plurality of predetermined substrates to be processed are housed in a substrate cassette as one unit (generally called a lot). Is a general operation method.

In a vacuum processing apparatus such as described above, particularly in an apparatus utilizing a reaction by an active gas such as a dry etching apparatus and a CVD apparatus, a reaction product adheres to and accumulates in a processing vessel as the processing is performed. Problems such as deterioration of performance, increase in dust, and decrease in the level of an optical monitor signal often occur. In order to avoid such problems, an operation of periodically cleaning the inside of the processing container is performed. The cleaning operation includes a so-called wet cleaning in which an adhering substance is wiped with an organic solvent or the like, and a dry cleaning using an active gas or plasma that decomposes the adhering substance, but from the viewpoint of workability and efficiency. With excellent dry cleaning, such features are becoming essential as production lines become more automated.

[0004] Further, for the above-mentioned reasons, in the vacuum processing apparatus, it is becoming indispensable to realize a function of checking the state of adhesion of the deposits in the vacuum processing chamber.

An example of a vacuum processing apparatus having such a function is the apparatus disclosed in Japanese Utility Model Application Laid-Open No. 63-127125.

In addition, regarding the loading / collection of wafers into the apparatus, conventionally, only a cassette dedicated to loading and recovering wafers or a cassette dedicated to loading / collecting wafers has been provided.

[0007]

Problems to be Solved by the Invention
In the apparatus disclosed in Japanese Patent No. 127125, a dummy wafer housed in a pre-vacuum chamber is loaded into the processing chamber before plasma cleaning the processing chamber, and when the plasma cleaning is completed, the dummy is transferred by the transfer means. The wafer is returned to the pre-vacuum chamber. For this reason, the vacuum pre-chamber containing the dummy wafer is
There is a problem that a large volume is required and a transfer mechanism dedicated to the dummy wafer is required, which complicates the apparatus.

In addition, since the normal processing is continued after the dummy wafer used for the plasma cleaning is returned to the vacuum preparatory chamber again, the used dummy wafer and the normal Unprocessed wafers to be subjected to the above processing are mixed, which is not preferable from the viewpoint of product contamination.

Also, when processing the product wafers, if the processed wafers are stored in the same cassette, dust from the processed wafers may adhere to the wafers before processing. .

In addition, as a method of loading / collecting wafers into the apparatus, if only one of a cassette dedicated to loading and recovering wafers and a cassette dedicated to loading / collecting wafers can be used, the form of the manufacturing line or the wafers Depending on the contents of the processing, there is a problem that it is not possible to selectively cope with a problem such as a reduction in the use efficiency of the apparatus due to a restriction on the timing of loading the cassette and a foreign matter dropping on an unprocessed wafer due to the processed wafer.

In addition, when a wafer is taken out of the cassette, a mechanism for handling the wafer is conventionally inserted into a fixed position of the cassette. However, the space between the wafer and the handling mechanism cannot be maintained, and the lower surface of the wafer cannot be maintained. And the handling mechanism comes into contact with each other, which may cause foreign matter.

An object of the present invention is to solve the above problems,
Dry cleaning and checking of deposits in the vacuum processing chamber can be performed efficiently without the installation of dedicated equipment, and the generation of dust, contamination of products due to residual gas, and contamination of products due to dust from other wafers are prevented. To achieve high productivity and high product yield, to prevent a decrease in the use efficiency of the apparatus due to the restriction of the cassette input timing depending on the form of the production line, and to prevent the post-processing wafer depending on the wafer processing content. An object of the present invention is to provide a vacuum processing apparatus capable of selecting a wafer transfer method capable of reducing the influence of foreign matter falling on an unprocessed wafer due to the above-mentioned method.

[0013]

In order to achieve the above object, the present invention provides a vacuum processing apparatus having a vacuum processing chamber in which a substrate to be processed is processed under vacuum and the inside of which is dry-cleaned. It is provided with a plurality of means installed in the atmosphere and for accommodating the substrate to be processed, and one of the means is a dummy substrate used in dry cleaning processing in a vacuum processing chamber or a dummy substrate to be inspected for deposits in the vacuum processing chamber. It can be used as a storage means.

Further, the means for accommodating the substrate to be processed is provided with a function that can be set only for carrying in to the vacuum processing chamber or only for carrying out of the vacuum processing chamber.

Further, when taking out a wafer from the cassette, a mechanism for handling the wafer is not inserted into a fixed position of the cassette. handling mechanism in which is to avoid contact.

[0016]

In the vacuum processing chamber, the substrate to be processed is processed under vacuum. As the process is performed, the reaction product adheres and accumulates in the vacuum processing chamber, which causes problems such as deterioration of vacuum performance, increase of dust, and reduction of the optical monitor signal level. Then, the inside of the vacuum vessel is subjected to dry cleaning treatment, and thereafter, the state of the deposit is examined. In other words, the dummy substrate is stored in one of the means for storing the substrate to be processed which is installed in the atmosphere, and the dummy substrate is carried out of the means by the means for transporting the dummy substrate.
It is conveyed to the vacuum processing chamber by the above means. After the dry cleaning in the vacuum processing chamber, the dummy substrate is returned from the vacuum processing chamber to the storage means for the dummy substrate by the reverse operation. Thereafter, a dummy substrate for inspecting the adhered substance in the vacuum processing chamber is stored in one of the means for installing the substrate to be processed in the atmosphere, and the dummy substrate is unloaded from the means by the means for transporting the dummy substrate. The unloaded dummy substrate is conveyed to the vacuum processing chamber by the above means. After the adhering matter investigation processing in the vacuum processing chamber, the dummy substrate is returned from the vacuum processing chamber to the storage means of the dummy substrate by the reverse operation. Further, in addition to the above-described processing, the means installed in the atmosphere for storing the substrate to be processed stores the product substrate and is used for processing the product substrate. When processing a product substrate, one of the means for storing the substrate to be processed is used to carry the product substrate into the vacuum processing chamber, and another one of the means for storing the substrate to be processed is used. Used to carry product substrates out of the vacuum processing chamber.

Further, by keeping the space between the wafer and the handling mechanism constant, foreign matter during wafer handling can be reduced without contact between the lower surface of the wafer and the handling mechanism.

That is, a vacuum spare chamber and a dedicated transfer mechanism for accommodating a dummy substrate as in the prior art are not required. Further, the means for accommodating the substrate to be processed can be used for a plurality of purposes, and a cassette and a wafer transfer mode can be selected according to the production line. Further, the dummy substrate used for the dry cleaning process and the substrate to be processed are not mixed. In addition, in the processing of product substrates, the influence of dust from unprocessed substrates during wafer handling and processed substrates can be reduced.

[0019]

An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a diagram showing an application of a vacuum processing apparatus according to the present invention to an apparatus for performing a dry etching process on a semiconductor wafer. The apparatus supplies a processing target to the apparatus in a state in which unprocessed wafers are stored, and a plurality (25) of storing and processing the processed wafers in the original position again.
Cassettes 1a, 1b,
1c and the cassettes 1a, 1b, 1c are placed thereon, and are always fixed on a horizontal or near-horizontal plane without changing the position and attitude for determining the position of introduction / dispense to the apparatus. Cassette tables 2a, 2b, 2c fixed to
And mapping devices 3a, 3b, 3c installed on the cassette tables 2a, 2b, 2c for detecting the positions of wafers in the cassettes 1a, 1b, 1c, and a vacuum exhaust device and a gas introducing device (not shown). a load lock chamber 5 for introducing the wafer into a vacuum atmosphere, as in the unload lock chamber 6 for taking out the wafer into the atmosphere, an etching chamber 11 for performing an etching process on a wafer, separating them hermetically, respectively Possible isolation valve 12 , load lock chamber 5 / unload lock chamber 6, and cassettes 1a, 1
b, is arranged between the 1c, X, Y, comprises a robot having a Z and Θ-axis, the load lock chamber 5 / unload-lock chamber 6 and the cassettes 1a, 1b, for exchanging wafers between 1c and a transport device 13. of.

An example of the operation of the apparatus will be described below. First, cassettes 1a and 1b containing unprocessed wafers are supplied from a stocker (not shown) to the apparatus by a robot or an operator, and are mounted on the cassette tables 2a and 2b. At this time, since the cassette tables 2a and 2b are on the same horizontal plane, the cassette supply operation can be simplified, and it is easy to respond to automation of the production line. on the other hand,
A cassette 1c containing dummy wafers is placed on the cassette table 2c. The apparatus performs processing on wafers by any method of recognizing the production information given to the cassette, based on information sent from a higher-level control device, or by an instruction input by an operator. Can be.

An empty cassette may be placed on one of the cassettes 1a and 1b. When both cassettes 1a and 1b are cassettes containing unprocessed wafers, wafers taken out of cassettes 1a and 1b are stored in the original cassette, but one of cassettes 1a and 1b is used as an empty cassette. In this case, the processed wafers can be stored in the original cassette or in an empty cassette. The instruction for this operation can be fixedly set for the apparatus or set for each processing unit.

At the start of processing, first, the state of storage of wafers in the cassette is checked. That is, the wafer detection sensor provided in the mapping device 3a is moved up and down along the cassette, and it is determined whether or not there is a wafer in each stage of the cassette based on a signal from the sensor. Wafer presence / absence data can be compared with wafer information in a cassette sent from a higher-level control device. When the wafer detection sensor provided in the mapping device 3a is raised along the cassette to check the storage state of the wafer in the cassette, if no wafer is present in the cassette, the mapping device 3a The height of the wafer support at each stage of the cassette can be determined based on a signal from the sensor for detecting the wafer support of the cassette provided in the cassette, and used as a reference height when the wafers are collected in the cassette.

After the wafer detecting operation, the unprocessed wafers 20 stored in the cassette 1a are extracted by the transfer device 13, and the unprocessed wafers 20 are loaded into the load lock chamber 5 arranged on the opposite side of the transfer device 13 from the cassette 1a. It is carried in through the isolation valve 12a. Here, when the transfer device 20 removes the wafer 20 from the cassette 1a, the position at which the wafer removal hand (not shown) of the transfer device 13 is inserted into the cassette 1a is based on the wafer lower surface position information obtained at the time of wafer detection. To decide. Further, only the wafer 2 is set in the cassette stage where it is determined that the wafer is present when the wafer is detected.
The operation of taking out 0 is performed.

The wafer 20 carried into the load lock chamber 5
May be stored in any place in the cassette 1a. After the wafer 20 enters the load lock chamber 5 from the isolation valve 12a, it is completely shut off from the atmosphere outside the apparatus until it leaves the unload lock chamber 6 from the isolation valve 12b. , 12b, a partition is provided, and only the cassette tables 2a, 2b and the cassettes 1a, 1b and the transfer device 13 placed thereon are placed on the clean room side with high cleanliness, and the remaining parts are cleaned. It can be placed on the lower maintenance room side. After closing the isolation valve 12a, the load lock chamber 5 is evacuated to a predetermined pressure by an exhaust device. Then, the isolation valve 12b is opened, and the wafer 20 is transferred to the etching chamber 11 and placed on the sample stage 8. Is placed.

The wafer 20 carried into the etching chamber 11
Is subjected to an etching process under predetermined conditions. During this time, the load lock chamber 5 is returned to the atmospheric pressure by the gas introduction device 4 with the isolation valves 12a and 12b closed, and the second wafer is opened from the opened isolation valve 12a similarly to the first wafer. The wafer is loaded by the transfer device 13 and evacuated again to a predetermined pressure by the exhaust device. When the etching of the first wafer 20 is completed, the isolation valve 12
c is opened, the processed wafer 20 is carried out to the unload lock chamber 6, and then the isolation valve 12c is closed, the isolation valve 12b is opened, and the second wafer is loaded in the load lock chamber 5.
Then, after the isolation valve 12b is closed, the etching process is started.

The processed wafer 20 carried out to the unload lock chamber 6 is returned to the atmospheric pressure in the unload lock chamber 6, then taken out to the atmosphere by the transfer device 13 through the isolation valve 12d, and initially stored. It is returned to the original position in the cassette 1a. Here, when an empty cassette is used as the cassette 1b and the setting is made so that the processed wafers are stored in the cassette 1b, the wafers 20 taken out into the atmosphere are stored in the cassette 1b. In this case, the wafer storage position d2 is d2 = D-d1 where D is the number of cassette stages and d1 is the stage from which the wafer is taken out. Thus, if the wafers are sequentially taken out from the lower side of the cassette 1a, the wafers can be stored from the upper side of the cassette 1b, and the influence of foreign matter on the unprocessed wafer and the processed wafer in wafer handling can be reduced. In addition, when storing wafers in the cassette 1b, the height at which the wafer handling mechanism is inserted into the cassette 1b is determined based on the height of the wafers in the cassette 1b as described above,
It is also possible to prevent the wafer and the wafer in the cassette 1b from interfering with each other.

By repeating the above operation, the processing of the unprocessed wafers stored in the cassette 1a is completed, and when the wafers are stored again in the original position, the cassette 1a can be collected and another unprocessed wafer is stored. Is replaced with a new cassette,
During this time, the apparatus continues to process the unprocessed wafers in the cassette 1b or the dummy wafers in the cassette 1c. Before the processing of the cassette 1b is completed, a cassette containing another unprocessed wafer is supplied. If this is the case, the device can always be operated continuously. At this time, since the cassette 1a and the cassette 1b are on the same horizontal plane, the operation of collecting the cassette 1a and the operation of supplying a cassette containing another unprocessed wafer are not affected by the access to the cassette 1b by the transfer device 13. Can be done without giving.

The above description has been given of the case where the wafer taken out of the cassette 1a is returned to the original position of the cassette 1a. However, even when the wafer is taken out of the cassette 1a and stored in the cassette 1b, the number of cassette tables is five and the number of cassettes is two. By using each of them in pairs, the device can always be operated continuously as described above.

In the etching chamber 11, the reaction product adheres to and accumulates on the inner wall surface as the processing is repeated. Therefore, it is necessary to remove the adhered substance by plasma cleaning and restore the original state. In performing the cleaning, the dummy wafer 30 stored in the cassette 1c is extracted by the transfer device 13, and thereafter, the processing is performed in the same manner as in the case of the wafer 20 to be processed. The dummy wafer 30 can be returned to the original position in the cassette 1c, and the dummy wafer 30 is always stocked in the cassette 1c. In addition, the dummy of the cassette 1c
If the entire wafer 30 is used for plasma cleaning or if it becomes unusable after several uses, the
The entire wafer 30 is exchanged for each cassette 1c.

In order to check the state of foreign matter in the etching chamber 11 after the plasma cleaning or the wet cleaning, the foreign matter checking wafer 40 is placed in the cassette 1c.
The foreign substance checking wafer 40 stored in the cassette 1c is withdrawn by the transfer device 13, and thereafter the processing is performed in the same manner as in the case of the wafer 20 to be processed. Can be returned to the original position in
Inspection of the etching chamber 1 by inspecting
The state of the foreign object can be checked.

As described above, there is no need to treat the plasma cleaning and the foreign substance check as a special processing sequence. The cleaning can be performed as a series of operations by incorporating the cleaning into a normal etching process. Can be set to A special mechanism for plasma cleaning and foreign substance check is not required from the hardware of the apparatus, and a cassette (book) containing the dummy wafer 30 or the foreign substance check wafer 40 in one of a plurality of cassette tables (2c in this example). Example 1
It is only necessary to install c). Plasma cleaning, in the case of not requiring the use of foreign matter check, instead of the cassette housing the dummy wafer 30 or a foreign matter check wafer 40, by placing a cassette accommodating the article to be treated wafer 20, a more efficient production It can be carried out.

Also, since the dummy wafer once used for plasma cleaning is returned to the original cassette in the atmosphere again, the used dummy wafer and the normal processing from now on are used in the vacuum processing chamber. Unprocessed wafers to be received do not mix, and there is no risk of product contamination. Further, since the used dummy wafer is returned to the original position in the cassette, it is not possible to confuse the used dummy wafer with an unprocessed dummy wafer or a less frequently used dummy wafer and a high used dummy wafer. In this case, the dummy wafer can be used effectively and inconveniently for plasma cleaning.

[0033]

As described above, according to the present invention, a vacuum pre-chamber for accommodating a dummy substrate and a dedicated transfer mechanism as in the prior art are not required. Further, the means for accommodating the substrate to be processed can be used for a plurality of purposes, and a cassette and a wafer transfer mode can be selected according to the production line.
Further, the dummy substrate used for the dry cleaning process and the substrate to be processed are not mixed. In addition, in the processing of product substrates, the influence of dust from unprocessed substrates during wafer handling and processed substrates can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing a dry etching apparatus as one embodiment of a vacuum processing apparatus of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate cassette, 2 ... Cassette stand, 3 ... Mapping device, 5 ... Load lock room, 6 ... Unload lock room, 8
... sample stage, 11 ... etching chamber, 12 ... isolation valve, 13 ...
Transfer device, 16: transfer chamber, 20: wafer, 30: dummy
Wafer, 40: wafer for foreign substance check.

Continuation of the front page (56) References JP-A-5-304197 (JP, A) JP-A-61-105853 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21 / 68

Claims (6)

(57) [Claims] 1. A vacuum processing chamber for processing a substrate under vacuum, and a cassette table provided on the atmosphere side and on which a plurality of substrate cassettes having a plurality of substrates for holding said substrate are arranged. A mapping device that moves along the substrate cassette to detect the position of a substrate in the substrate cassette and the substrate support of the substrate cassette; and transports the substrate between the vacuum processing chamber and the substrate cassette. Transport means, and means for selecting storage of the processed substrate in the vacuum processing chamber in the substrate cassette from which the substrate has been carried out, or storage in another substrate cassette, wherein the substrate is contained in the substrate cassette. Vacuum processing, wherein when not present, the substrate support height based on the detection signal from the mapping device is set as a reference height when the substrate is collected into the substrate cassette. Location. 2. The vacuum processing apparatus according to claim 1, wherein one of said plurality of substrate cassettes is a substrate cassette for storing a dummy substrate used in a dry cleaning process. 3. A vacuum processing apparatus according to claim 1, wherein one of said plurality of substrate cassettes is a substrate cassette for storing a dummy substrate for checking foreign substances in said vacuum processing chamber. 4. The apparatus according to claim 1, wherein one of said plurality of substrate cassettes is a substrate cassette for storing a dummy substrate used in a dry cleaning process or a foreign substance in said vacuum processing chamber. Vacuum processing device used as a substrate cassette for storing dummy substrates. 5. The vacuum processing apparatus according to claim 1, wherein the stage of the substrate cassette to be stored in said another substrate cassette is the same as the stage taken out. 6. A vacuum processing apparatus according to claim 1, wherein the stage of the substrate cassette to be stored in said another substrate cassette is vertically symmetrical with the stage taken out.