JP2007311393A - Detector of deposit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain the timing of maintenance accurately in a semiconductor production system. <P>SOLUTION: In order to detect the quantity of deposit in the exhaust pipe 10 of a semiconductor production system, temperature sensors (20, 30) for detecting the temperature of the exhaust pipe 10 are provided. Based on the memory information about correlation of pressure, temperature, and thickness of deposit predetermined depending on the type of processing gas and the temperature information obtained by the temperature sensors 20 and 30, the thickness α of deposit in the exhaust pipe 10 is calculated and when the calculation value reaches a limit deposit thickness, necessity of maintenance is informed by an informing means 100. Since the thickness of deposit can be detected accurately depending on the type of processing gas, optimal timing of maintenance can be known without waste resulting in enhancement of efficiency and yield of the semiconductor production system. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a deposit detection apparatus that detects the amount of deposits such as by-products deposited on the inner wall surface of a processing chamber or the inner wall surface of an exhaust pipe in a semiconductor manufacturing apparatus and notifies the maintenance timing for cleaning. .

  In a CVD apparatus or an etching apparatus, by-products are generated in the processing chamber or the evacuated exhaust pipe (foreline) based on various chemical-physical reactions, and the generated by-products are the atmospheric pressure. Depending on the temperature, the gas state is maintained, or it appears as a deposit that sublimates into a solid and adheres to the inner wall surface.

  Since these deposits adversely affect the production of semiconductors, it is necessary to periodically remove them by performing maintenance. Conventional maintenance time management is to manage the operation time of the equipment using the cumulative value of the total gas used for film formation and etching processing, the total film thickness by film type and the total etching film thickness, etc. as indicators. there were. These management methods are rough based on empirical rules and cannot be accurately managed.

On the other hand, as a technique for detecting the amount of deposit adhering, a pair of transparent bodies is provided so as to be opposed to each other with a passage between pipes, and a light sensor including a light emitting element and a light receiving element is disposed outside the transparent body. That detects the amount of deposits (by-products) adhering to the inner wall surface of the transparent body based on a change in the amount of light received by the light receiving element through the transparent body (see, for example, Patent Document 1) ).
However, with this detection method, it is difficult to accurately detect the amount (thickness) of the deposit even though it is possible to roughly grasp whether or not the deposit has adhered. is not.

Further, as another technique for detecting the amount of deposits attached, a pair of electrodes is arranged in the pipe, and the amount of deposits (by-products) is detected based on a change in capacity between the pair of electrodes. It is known (see, for example, Patent Document 2).
However, in this detection method, since the pair of electrodes are directly exposed to the atmosphere in which the by-product is generated, there is a risk of deterioration of the electrodes over time, and it is difficult to detect stably and accurately. .

Japanese Patent Laid-Open No. 11-2601 JP-A-11-23511

  The present invention has been made in view of the above-mentioned problems of the prior art, and the object of the present invention is such as the type of processing of semiconductor manufacturing, the type of processing gas used, the flow rate and pressure in the piping, etc. Based on the sublimation characteristics of the by-product depending on the process conditions, the amount of time-series deposition when the by-product is solidified and deposited can be detected with high accuracy by a simple method. It is an object of the present invention to provide a deposit detection apparatus that can accurately grasp the time and can improve the efficiency of semiconductor manufacturing and the yield.

The deposit detection apparatus according to the present invention is a deposit deposited in the interior of a wall forming a processing chamber, a transport passage for taking wafers into and out of the processing chamber, or an exhaust passage for discharging processing gas in the processing chamber. Is a deposit detection device for detecting the amount of deposits, and relates to the relationship between the temperature sensor for detecting the temperature of the wall and the pressure, temperature, and deposit thickness determined in advance according to the type of processing gas. Based on the stored information and the temperature information obtained by the temperature sensor, a calculation means for calculating the thickness of the deposit deposited inside the wall body, and maintenance when the calculated value obtained by the calculation means is a predetermined value or more And a notification means for notifying that it is necessary.
According to this configuration, when deposits such as by-products are attached (deposited) to the inner wall surface of a wall such as a pipe that forms an exhaust passage or the like, the deposits serve as a heat insulating layer, The temperature of the wall body decreases as the deposition amount (thickness) increases. Therefore, when the temperature of the wall body is detected by the temperature sensor, the calculation means stores this temperature information in relation to the correlation between the pressure, temperature, and deposit thickness obtained in advance according to the type of the processing gas. The thickness of the deposit corresponding to this temperature is calculated. Then, the notification means notifies that maintenance is required when the calculated value is equal to or greater than a predetermined value (limit deposition thickness). In this way, because the thickness of the deposit can be detected accurately according to the type of processing gas, it is possible to know the timing of maintenance at the optimum timing without waste, improving the efficiency of semiconductor manufacturing and improving the yield. can do.

The above configuration includes a pressure sensor for detecting the pressure inside the wall body, and the calculation means calculates the thickness of the deposit deposited inside the wall body based on the recorded information and the pressure information obtained by the pressure sensor. The calculated configuration can be adopted.
According to this configuration, when the pressure inside the wall body is detected by the pressure sensor, the calculation means uses the pressure information obtained in advance according to the type of the processing gas, the temperature, and the thickness of the deposit. The thickness of the deposit corresponding to this pressure is calculated in comparison with the stored information regarding the correlation. Thereby, the more accurate thickness of the deposit can be detected.

In the above configuration, the pressure sensor can employ a configuration provided in the vicinity of the temperature sensor.
According to this configuration, since the correspondence relationship between the pressure information obtained by the pressure sensor and the temperature information obtained by the temperature sensor becomes more accurate, the calculated value (thickness of the deposit) calculated by the calculating means is also greater. Obtained as highly accurate information.

In the above configuration, the temperature sensor may employ a configuration including a main temperature sensor and a sub temperature sensor.
According to this configuration, based on the temperature information detected by the main temperature sensor and the temperature information detected by the sub temperature sensor, it is possible to calculate information regarding the thickness of the deposits in a double manner. It is possible to obtain a calculated value with higher accuracy in consideration.

In the above configuration, the temperature sensor and the pressure sensor may employ a configuration provided in an elbow pipe formed by bending the exhaust passage.
According to this configuration, deposits such as by-products are likely to be generated particularly on the bent elbow pipe (inner wall surface thereof). Therefore, by providing a temperature sensor and a pressure sensor in this region, an exhaust passage having a bent shape is provided. Thus, the amount of deposit can be detected more accurately.

The above configuration includes a gas amount detection sensor for detecting the total amount of exhaust gas discharged from the exhaust passage, and the calculating means calculates the total exhaust gas amount determined in advance according to the type of the processing gas and the thickness of the deposit. It is possible to employ a configuration in which the thickness of the deposit deposited inside the wall body is calculated based on the stored information related to the relationship and the information obtained by the gas amount detection sensor.
According to this configuration, when the total amount of exhaust gas is detected by the gas amount detection sensor, the calculation means uses the information on the total amount of exhaust gas as the total amount of exhaust gas determined in advance according to the type of processing gas. The thickness of the deposit corresponding to this total exhaust gas amount is calculated in comparison with the stored information relating to the relationship with the thickness of the deposit. Thereby, a comprehensive double check becomes possible, and the amount of deposits can be detected more accurately.

The said structure WHEREIN: The structure by which the planar heating unit heated to planar shape is arrange | positioned adjacent to the inner wall surface of a wall body is employable.
According to this configuration, it is possible to detect the amount of by-products deposited on the inner wall surface of the wall body in the area where the planar heating unit is disposed, so that the maintenance of the planar heating unit can be efficiently performed at a desired timing. It can be carried out.

  According to the deposit detection apparatus configured as described above, by-products that depend on processing conditions such as the type of processing (process) of semiconductor manufacturing, the type of processing (process) gas used, the flow rate and pressure in the pipe, and the like. Based on the sublimation characteristics, the amount of accumulated by-products etc. can be detected with high accuracy by a simple method, and the maintenance cycle or timing can be accurately grasped, improving semiconductor manufacturing efficiency and yield. The

DESCRIPTION OF EXEMPLARY EMBODIMENTS Embodiments of the invention will be described below with reference to the accompanying drawings.
1 to 8 show an embodiment of a deposit detection apparatus according to the present invention. FIG. 1 is an overall system diagram, FIG. 2 is a sectional view showing an exhaust pipe of a semiconductor manufacturing apparatus, and FIG. 4 is a partial cross-sectional view showing an enlarged part of the exhaust pipe, FIG. 5 is a diagram showing the relationship between pressure and temperature according to the type of processing gas, and FIG. 6 is the temperature and by-product according to the type of processing gas. FIG. 7 is a diagram showing the relationship between the deposit thickness of the product (sediment), FIG. 7 is a diagram showing the relationship between the total exhaust gas amount according to the type of processing gas and the deposit thickness of the by-product (sediment), and FIG. It is a flowchart which shows the whole control sequence.

As shown in FIG. 1, this system processes signals of a main temperature sensor 20, a sub temperature sensor 30, a pressure sensor 40, a main temperature sensor 20, and a sub temperature sensor 30 provided in an exhaust pipe 10 of a semiconductor manufacturing apparatus. The pressure detection circuit 50 to be sent to the control circuit 80 to be described later, the pressure detection circuit 60 to process the signal of the pressure sensor 40 and send it to the control circuit 80 to be described later, the pressure, temperature, and deposition determined in advance according to the type of processing gas Calculation means for performing various arithmetic processes and generating control signals based on signals and storage information of the storage unit 70, temperature detection circuit 50, pressure detection circuit 60, and storage unit 70 that store information relating to the mutual relationship between the thicknesses of objects Control circuit 80 as a notification means, a notification signal generation circuit 90 as notification means for generating a notification signal based on a command signal issued from the control circuit 80, and a notification signal generation And a sound generator 100 or the like for generating an alarm sound based on the output signal of the circuit 90.
Further, as shown in FIG. 1, this system is a gas amount detection sensor 110 that detects the total amount of exhaust gas discharged from the exhaust pipe 10, and the total amount of the gas amount detection sensor 110 that processes the signal and sends it to the control circuit 80. An exhaust gas amount detection circuit 120 and the like are provided.

The exhaust pipe 10 forms an exhaust passage for exhausting the processing gas in the processing chamber. As shown in FIGS. 2 and 3, the exhaust pipe 10 is a straight pipe that defines an inner wall surface 10a, an outer surface 10b, and a flange portion 10c. 11 and an elbow pipe 12, and a planar heating unit 13 is disposed adjacent to the inside of the straight pipe 11 and the elbow pipe 12. The straight pipes 11 or the straight pipes 11 and the elbow pipes 12 are connected by a chain clamp 15 with a seal ring 14 sandwiched between the flange portions 10c.
As shown in FIG. 3, the planar heating unit 13 is sandwiched between a cylindrical inner shell 13 a and an outer shell 13 b, a thin plate-like resistance heating element 13 c sandwiched between the shells 13 a and 13 b, and attached at the time of attachment. The flange portion 13d is formed. The planar heating unit 13 is adjacent to cover the inner wall surface 10a of the exhaust pipe 10 (straight pipe 11 and elbow pipe 12), that is, a slight gap is formed between the inner wall surface 10a and the outer shell 13b. Arranged.

The main temperature sensor 20 and the sub temperature sensor 30 are attached to the wall of the exhaust pipe 10 from the outside and detect the temperature of the outer surface 10b, so that the temperature can be detected over the entire area of the exhaust pipe 10. A plurality are provided.
Here, the role of the main temperature sensor 20 and the sub temperature sensor 30 will be described with reference to FIG. 4 from the viewpoint of heat transfer characteristics. A part of the heat generated in the planar heating unit 13 is separated from the outer shell 13b. Heat is transferred to the outer surface 10b of the exhaust pipe 10 (wall body) provided with the main temperature sensor 20 through the processing gas (molecules) existing in the gap formed between the wall surface 10a, and on the other hand, However, there is also heat transfer as radiant heat, and part of the heat generated in the planar heating unit 13 is transferred to the exhaust pipe 10 as heat conduction through the flange portions 13d and 10c, and the sub temperature sensor 30 is provided. It is transmitted in the axial direction from the provided area toward the area where the main temperature sensor 20 is provided.

Here, when deposits such as by-products adhere (deposit) to the inner wall surface 10a of the exhaust pipe 10 (wall body), the deposits serve as a heat insulating layer, and the outer surface of the exhaust pipe 10 The temperature of 10b decreases in inverse proportion as the amount of deposition (thickness) increases.
Therefore, the temperature of the region heated by the radiant heat using the processing gas as a medium changes according to the thickness of the deposit, and the change in temperature is detected by the main temperature sensor 20. On the other hand, the temperature of the region directly heated using the solid (the planar heating unit 13 and the wall of the exhaust pipe 10) as a medium is detected by the sub temperature sensor 30.
Thus, by detecting the temperatures of the region away from the flange portions 10c and 13d and the region close to the flange portions 10c and 13d with the separate temperature sensors 20 and 30, accurate temperature detection in consideration of variation is performed. be able to.
As the main temperature sensor 20 and the sub temperature sensor 30, for example, a thermocouple, a thermistor, a platinum resistance thermometer, or the like that performs thermoelectric conversion is employed. The sub temperature sensor 30 is not necessarily required, and may be appropriately provided at a place where the temperature is to be detected more accurately.

The pressure sensor 40 is attached to the wall of the exhaust pipe 10 from the outside and detects the pressure inside the exhaust pipe 10. Like the temperature sensors 20 and 30, the pressure sensor 40 detects the pressure over the entire area of the exhaust pipe 10. A plurality of them may be arranged so that deposits can easily accumulate in the bent exhaust passage. Therefore, it is particularly preferable to provide the elbow pipe 12 in the bent exhaust passage.
As the pressure sensor 40, for example, a sensor constituted by a vacuum gauge such as a Pirani vacuum gauge or a diaphragm type capacitance manometer is employed. Note that the pressure sensor 40 is not necessarily required, and may be appropriately provided at a place where it is desired to grasp the thickness of the deposit more accurately.

The positional relationship between the pressure sensor 40 and the temperature sensors 20 and 30 is such that, for example, the temperature sensors 20 and 30 are positioned in the vicinity of the circumference centered on the pressure sensor 40 or in the vicinity of the axial direction of the exhaust pipe 10. Be placed.
As described above, by arranging the temperature sensors 20 and 30 and the pressure sensor 40 in the vicinity, the correspondence between the pressure information obtained by the pressure sensor 40 and the temperature information obtained by the temperature sensors 20 and 30 can be made with higher accuracy. Therefore, the calculated value (thickness of the deposit) calculated by the control circuit 80 is also obtained as more accurate information.

In the storage unit 70, a sublimation curve corresponding to the type of process (process) and the type of process gas (for example, a, b, c...), More specifically, the deposit as shown in FIG. Data information on the relationship between the pressure P and the temperature T for each thickness (α1, α2, α3...), Types of processing gases (a, b, c, etc.) as shown in FIGS. ..), Data information on the relationship between the main temperature T and the deposit thickness α and the relationship between the sub-temperature T and the deposit thickness α, and the types of processing gases (a, Data information on the relationship between the total exhaust gas amount Q and the deposit thickness α according to (b, c...) is obtained in advance for each processing gas and stored as storage information. The data on the thickness α of the deposit is obtained and stored in advance according to the type of by-product.
The stored information is used when calculating the thickness α of the deposit by comparing the temperature information or pressure information detected by the temperature sensor 20 or 30 or the pressure sensor 40 with the actual exhaust pipe 10 or the like. Is.

Here, the knowledge obtained from the evaluation experience in actual processing in the manufacture of semiconductors is the processing used depending on the purpose of processing (what film is formed, what film is etched, etc.) Processing conditions such as the type, flow rate, and pressure of the gas are determined, and as a result, the sublimation characteristics when by-products and the like are solidified and deposited on the inner wall surface 10a of the exhaust pipe 10 or the like are specified.
Further, when by-products or the like are deposited, the deposit becomes a heat insulating layer and suppresses heat transfer to the outside. Therefore, the temperature detected on the outer surface 10b of the exhaust pipe 10 or the like is the amount of deposition ( A certain relationship is obtained that the thickness decreases as the deposit thickness increases.
From these findings, if the interrelationships such as internal pressure P, temperature T, deposit thickness α, etc., according to the type of semiconductor manufacturing process (process) and the type of processing gas used are known, In an actual semiconductor manufacturing apparatus, by detecting the temperature, pressure and the like during processing, it is possible to determine the amount of deposited by-products or the thickness of the deposit.
Therefore, as described above, data relating to the correlation between the pressure P, the temperature T, and the deposit thickness α determined according to the type of the processing gas is stored in the storage unit 70 in advance as storage information.

The control circuit 80 stores temperature information and pressure information detected by the temperature sensors 20 and 30 and the pressure sensor 40 in the storage unit 70 and stores the information (according to the type of processing gas as shown in FIGS. 5 and 6). The thickness α of the deposit corresponding to the detected temperature and pressure is calculated in comparison with the pressure, temperature, and deposit thickness data obtained in advance, and the calculated value is a predetermined value ( It is determined whether or not it is equal to or greater than the limit deposition thickness. The control circuit 80 obtains information on the total exhaust gas amount detected by the gas amount detection sensor 110 in advance according to the stored information stored in the storage unit 70 (the type of processing gas as shown in FIG. 7). And the deposit thickness α corresponding to the detected total exhaust gas amount is calculated, and the calculated value is a predetermined value (limit deposition). It is determined whether the thickness is equal to or greater than (thickness).
When the calculated value is equal to or greater than a predetermined value, a control signal is issued to the notification signal generation circuit 90 so that the sound generator 100 emits a notification sound.
In this way, the control circuit 80 takes in various detection data, performs various arithmetic processes such as comparison and determination with stored information, and issues a command signal for overall control. In the actual semiconductor manufacturing apparatus, the host computer plays the role of the control circuit 80.
In addition to the temperature information and pressure information of the temperature sensors 20, 30 and the pressure sensor 40, the gas amount detection sensor 110 calculates the thickness α of the deposit based on the information of the total exhaust gas amount Q. Since it can be added as a judgment material when performing, a comprehensive double check becomes possible, and the amount of deposit (the thickness α of the deposit) can be detected more accurately.

Next, the operation of this detection apparatus will be described with reference to the flowchart shown in FIG. Here, it is assumed that the main temperature sensor 20, the sub temperature sensor 30, the pressure sensor 40, and the gas amount detection sensor 110 are all employed in the system.
First, there is information on the type of processing such as film forming processing, etching processing, the type of processing gas used in the processing (a, b, c...), And the type of by-product. The control information is input to the host computer (steps S1, S2, S3).

  Then, the temperature information detected by the main temperature sensor 20 and the sub temperature sensor 30, the pressure information detected by the pressure sensor 40, and the information of the total exhaust gas amount detected by the gas amount detection sensor 110 are respectively sent to the control circuit 80. It is taken in and compared with the storage information (data information shown in FIGS. 5, 6, and 7) stored in advance in the storage unit 70 (step S4), and the value of the corresponding deposit thickness α is calculated. (Step S5).

  Subsequently, it is determined whether or not the calculated value (deposit thickness α) is equal to or greater than the limit deposition thickness (step S6). Here, when it is determined that the calculated value is less than the limit deposition thickness, the process returns to step S4 again and the same loop is repeated. On the other hand, when it is determined that the calculated value is equal to or greater than the limit deposition thickness, the control circuit 80 issues a command signal to the notification signal generation circuit 90, and the sound generator 100 generates an alarm (notification sound) (step S7). As a result, the operator can recognize that the semiconductor manufacturing apparatus needs to be maintained for cleaning, and can then stop the apparatus.

  As described above, according to the deposit detection apparatus, the type of processing (process) of the semiconductor manufacturing apparatus such as the CVD apparatus and the etching apparatus, the type of processing (process) gas used, the pressure and temperature in the exhaust pipe 10 On the basis of the sublimation characteristics of by-products depending on the processing conditions such as, it is possible to detect the accumulation amount of by-products with high accuracy by a simple method. Therefore, it is possible to accurately grasp the timing or period of maintenance such as cleaning, improve the semiconductor manufacturing efficiency, and improve the yield.

In the above-described embodiment, the temperature sensors 20 and 30 and the pressure sensor 40 are provided for the exhaust pipe 10 as a wall body. However, the present invention is not limited to this. The temperature sensors 20 and 30 and the pressure sensor 40 may be provided on a wall that forms a conveyance path for taking a wafer into and out of the chamber, or on a wall that exists in another processing path.
In the above embodiment, the configuration including the main temperature sensor 20 and the sub temperature sensor 30 is shown. However, the sub temperature sensor 30 is not always necessary, and the configuration including the pressure sensor 40 and the gas amount detection sensor 110 is illustrated. However, these are not necessarily required.

  As described above, the deposit detection apparatus according to the present invention can grasp the accumulation amount of by-products and the like with high accuracy, so that it is of course useful for a CVD apparatus and an etching apparatus. It is also useful in other semiconductor manufacturing apparatuses.

1 is a system diagram showing an outline of a deposit detection apparatus according to the present invention. It is sectional drawing of the exhaust pipe which employ | adopted the detection apparatus of this invention. It is a fragmentary sectional view of the exhaust pipe which employ | adopted the detection apparatus of this invention. It is a fragmentary sectional view of the exhaust pipe which employ | adopted the detection apparatus of this invention. It is the figure which showed the relationship between the thickness of a deposit, pressure, and temperature. (A) is the figure which showed the relationship between the main temperature according to the kind of process gas, and the thickness of a deposit, (b) is the relationship between the sub temperature according to the kind of process gas, and the thickness of a deposit. FIG. It is the figure which showed the relationship between the total exhaust gas amount according to the kind of process gas, and the thickness of a deposit. It is a flowchart which shows the control sequence in a detection apparatus.

Explanation of symbols

10 Exhaust pipe (wall)
10a Inner wall surface 10b Outer surface 10c Flange part 11 Straight pipe 12 Elbow pipe 13 Planar heating unit 13a Inner shell 13b Outer shell 13c Resistance heating element 13d Flange part 14 Seal ring 15 Chain clamp 20 Main temperature sensor 30 Sub temperature sensor 40 Pressure sensor 50 temperature detection circuit 60 pressure detection circuit 70 storage unit 80 control circuit (calculation means)
90 Notification signal generation circuit (notification means)
100 Sound generator (notification means)
110 Gas amount detection sensor 120 Total exhaust gas amount detection circuit

Claims (7)

Detection of deposits for detecting the amount of deposits deposited in the interior of a wall forming a processing chamber, a transport passage for taking wafers in and out of the processing chamber, or an exhaust passage for discharging processing gas in the processing chamber A device,
A temperature sensor for detecting the temperature of the wall;
Deposits deposited in the wall based on stored information on the correlation between pressure, temperature, and deposit thickness determined in advance according to the type of processing gas and temperature information obtained by the temperature sensor Calculating means for calculating the thickness of
Informing means for informing that maintenance is required when the calculated value obtained by the calculating means is equal to or greater than a predetermined value;
The deposit detection apparatus characterized by including. Including a pressure sensor for detecting the pressure inside the wall,
The calculation means calculates the thickness of the deposit deposited inside the wall body based on the recording information and the pressure information obtained by the pressure sensor.
The deposit detection apparatus according to claim 1. The pressure sensor is provided in the vicinity of the temperature sensor,
The deposit detection apparatus according to claim 2. The temperature sensor includes a main temperature sensor and a sub temperature sensor.
The deposit detection apparatus according to any one of claims 1 to 3. The temperature sensor and the pressure sensor are provided in an elbow pipe formed by bending the exhaust passage.
The deposit detection apparatus according to any one of claims 2 to 4, wherein the deposit detection apparatus is provided. A gas amount detection sensor for detecting the total amount of exhaust gas discharged from the exhaust passage,
The calculating means is based on stored information on the relationship between the total exhaust gas amount determined in advance according to the type of the processing gas and the thickness of the deposit and information obtained by the gas amount detection sensor. Calculate the thickness of the sediment deposited inside,
The deposit detection apparatus according to claim 1, wherein the deposit detection apparatus includes: On the inner wall surface of the wall body, a planar heating unit for heating in a planar shape is disposed adjacently,
The deposit detection apparatus according to any one of claims 1 to 6,

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