JP2007024814A - Film thickness measurement method and device, and deposition apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure the thickness of a film regardless of the thickness in a film thickness measuring device. <P>SOLUTION: In the film thickness measuring device, a piezo element 4 excited by the supply of power from an AC power supply 3 is mounted on a support section 2. On end section of a cantilever 5 having a measurement section 6 is fixed to the piezo element 4. A piezo resistance element 7 and a heater 8 are incorporated in the cantilever 5. The piezo element 4 is excited, and the resonance frequency of the cantilever 5 changing with an increase in the thickness of a film formed on the surface of the measurement section 6 is observed by a signal processor 11. A storage 13 stores data for indicating the relationship between the thickness of the film formed in the cantilever 5 and the resonance frequency of the cantilever 5 in advance. By comparing the data and the observed resonance frequency by an arithmetic unit 14 for verification, the thickness and formation rate of the film at the measurement section 6 can be measured. A film thickness measurement method can use the film thickness measuring device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a film thickness measuring method, a film thickness measuring apparatus, and a vapor deposition apparatus using the film thickness measuring apparatus.

  For example, in a vapor deposition apparatus that vaporizes or sublimates a vapor deposition material and deposits the vapor on a substrate, it is necessary to accurately measure the thickness of the film deposited by vapor deposition on the substrate surface.

  Conventionally, a film is deposited on the surface of the crystal unit, and the film thickness is detected from the change in the resonance frequency of the crystal unit, assuming that the mass of the film is equal to the mass increase of the crystal unit. However, since there is a limit to the film thickness that can be detected by the quartz crystal, the quartz crystal is heated recently, and the deposition rate on the quartz crystal is more intentional than the deposition target. From the relationship between the film formation temperature and the film formation rate obtained in advance, the ratio of the film formation rate is calculated from the temperature of the object to be formed and the temperature of the crystal unit. It has been proposed to calculate the film thickness on the film formation target by detecting the film thickness (see Patent Document 1).

JP-A-10-111121

  However, even if only the crystal unit is heated and the film formation rate is intentionally reduced in this way, it is expected that measurement will become impossible when the deposited film reaches a certain thickness. In addition, since the quartz crystal is still used, there is a limit to the heating temperature, and the deposited film cannot be heated enough to evaporate. Consequently, the quartz crystal must be cleaned frequently. This will affect the operating rate of the equipment.

  The present invention has been made in view of the above points, and in a film thickness measuring apparatus, it is possible to measure the film thickness regardless of the film thickness, and it is easy to evaporate the deposited film, so that a maintenance cycle is possible. The purpose is to lengthen.

  In order to achieve the above object, the present invention is a method for measuring the thickness of a film formed on a cantilever, wherein the cantilever attached to the piezo element is vibrated by a piezo element excited by supply of AC power. The resonance frequency of the cantilever was measured, and the measured resonance frequency was compared with the relationship between the film thickness of the film formed on the cantilever and the resonance frequency of the cantilever, which was obtained in advance. It is characterized by obtaining the film thickness.

  According to the present invention, since the thickness of the film formed on the surface of the cantilever is measured based on the resonance frequency of the cantilever by the piezo element without using a crystal resonator, this is possible regardless of the thickness of the formed film. Can be measured.

  According to another aspect of the present invention, a film thickness measuring apparatus of the present invention includes a piezo element excited by supply of AC power, a cantilever attached to the piezo element, and a piezoresistive element provided on the cantilever. And an observation device for observing the vibration frequency of the cantilever based on the strain received by the piezoresistive element.

  According to the present invention, for example, by placing a cantilever in the vicinity of a measurement object having a film thickness formed on the surface, the thickness of the same film as the film formed on the measurement object surface is measured in real time. Is possible.

  In the film thickness measuring device of the present invention, the storage device storing the relationship between the film thickness of the film formed on the cantilever and the resonance frequency of the cantilever, the resonance frequency observed by the observation device, and the storage device You may make it further have an arithmetic unit which compares and collates with the stored data.

  Furthermore, if a heater for heating the cantilever is further added, the film component formed on the cantilever surface can be evaporated, and the maintenance cycle can be lengthened.

  Further, according to another aspect of the present invention, the vapor deposition apparatus of the present invention is characterized in that any one of the above-described film thickness measuring apparatuses is disposed in the peripheral portion of the substrate. In such a case, if the apparatus further includes a control device that controls a vapor deposition source for vaporizing or sublimating the vapor deposition material based on the film thickness or the film formation rate measured by the film thickness measurement device, the predetermined film thickness can be obtained. Forming on the surface is done automatically.

The type of the vapor deposition apparatus includes, for example, a vapor deposition source that vaporizes or sublimates the vapor deposition material accommodated in the accommodating portion, a guide path that guides vapor of the vapor deposition material generated from the vapor deposition source toward the substrate, and the guide path An outlet for releasing steam from the substrate toward the substrate;
A damper for controlling the flow rate of the vapor of the vapor deposition material discharged from the discharge port through the guide path, the film thickness measuring device described above at the discharge port, and the film thickness measured by the film thickness measuring device Or it is good also as a structure which further has a control apparatus which controls the said damper based on a film thickness formation rate.

  An apparatus for depositing a vapor deposition material on a substrate held in a processing vessel, the vapor deposition source vaporizing or sublimating the vapor deposition material accommodated in a container, and the vapor of the vapor deposition material generated from the vapor deposition source on the substrate A flow path leading to the guide path in the vapor deposition source, and a film thickness measuring device as described above. A flow controller for controlling the flow rate of vapor of the vapor deposition material passing through the path, and a controller for controlling the flow controller based on a film thickness or a film formation rate measured by the film thickness measuring device. It is good also as a structure.

  According to the present invention, the film thickness can be measured regardless of the thickness of the formed film. In addition, it is possible to evaporate the components of the film formed on the cantilever by heating with a heater and remove it, so the maintenance cycle can be longer than before and the operating rate of the equipment can be improved. become.

  Hereinafter, preferred embodiments of the present invention will be described. FIG. 1 shows an outline of the configuration of a film thickness measuring apparatus 1 according to an embodiment. A piezoelectric element 4 that is excited by AC power supplied from an AC power supply 3 is attached to a support unit 2. In the piezo element 4, for example, vibration with a steady frequency of 100 Hz to 10 kHz is generated.

  One end of the cantilever 5 is fixed to the piezo element 4 and the other end is a free end. The cantilever 5 is made of, for example, silicon. A specific surface, for example, the lower surface, of the cantilever 5 constitutes the measuring unit 6. A piezoresistive element 7 is provided inside the cantilever 5. Further, the cantilever 5 is provided with a heater 8. In the present embodiment, a heater 8 is provided inside the cantilever 5. The heater 8 generates heat when power is supplied from the heating power source 9. The heating power source 9 may be shared with the AC power source 3.

  In order to store and integrate the piezoresistive element 7 and the heater 8 in the cantilever 5, for example, a Mems technique can be used.

  The resistance value of the piezoresistive element 7 changes due to the strain received by the resistive element itself as the cantilever 5 vibrates, and an electric signal based thereon can be obtained by an appropriate circuit. Therefore, the vibration frequency when the cantilever 5 vibrates by the excitation of the piezo element 4, that is, the resonance frequency of the cantilever 5 can be measured by the signal from the piezoresistive element 7.

  A variation signal of the resistance value from the piezoresistive element 7 due to the vibration of the cantilever 5 is converted into a frequency signal by the signal processing device 11 and can be observed by the signal processing device 11. Therefore, in the present embodiment, the signal processing device 11 also functions as an observation device.

  The frequency signal from the signal processing device 11, that is, the resonance frequency of the cantilever 5 is output to the processing device 12. For example, a personal computer or the like can be used as the processing device 12. In the processing device 12, a storage device 13 that stores the relationship between the film thickness of the film formed on the measuring unit 6 of the cantilever 5 and the resonance frequency of the cantilever 5, which has been examined in advance, and the signal processing An arithmetic device 14 is provided for comparing and comparing the resonance frequency from the device 11 and the data stored in the storage device 13.

  The film thickness measuring apparatus 1 has the main configuration as described above. When a film is formed by vapor deposition of evaporation material, for example, with respect to the measurement unit 6 of the cantilever 5, the measurement unit 6 is formed over time. As the film accumulates on the surface of the film, the film thickness increases. It is known from the inventors' knowledge that the resonance frequency of the cantilever 5 also changes at this time.

  That is, as shown in FIG. 2, for example, when the resonance frequency at a film thickness of 0 [nm] is f0, the resonance frequency changes to f1 as the film thickness increases to x [nm]. Therefore, by previously obtaining the relationship between the film thickness of the cantilever 5, for example, the measurement unit 6, and the resonance frequency, the resonance frequency observed by the signal processing device 11 is collated with the relationship obtained in advance. It is possible to measure the film thickness of the film on which the measurement unit 6 is formed. Therefore, the arithmetic unit 14 compares the data stored in the storage device 13 with the observation data from the signal processing device 11 to compare the film thickness and thickness of the film formed on the surface of the measurement unit 6 in real time. The formation rate and the like can be measured.

  Further, according to the knowledge of the inventors, the relationship between the film thickness and the resonance frequency has a relationship in which the resonance frequency changes as the film thickness increases. Regardless, it is possible to measure the film thickness on the surface of the measurement unit 6.

  Moreover, since the heater 8 is built in the cantilever 5 and the measuring part 6 of the cantilever 5 can be heated, the formed film can be heated and evaporated. Therefore, cleaning when changing the film type can be omitted, and the overall maintenance cycle can be extended.

  Next, a vapor deposition apparatus using the film thickness measuring apparatus 1 will be described. FIG. 3 shows an outline of the configuration of the vapor deposition apparatus 31 according to the first embodiment, and this vapor deposition apparatus 31 has a processing vessel 32 that forms a processing space 32a therein. A guide member 33 and a support member 34 that is moved along the guide member 33 by an appropriate drive source (not shown) are provided in the upper portion of the processing container 32. A substrate holding unit 35 such as an electrostatic chuck is attached to the support member 34, and the substrate W as a film formation target is held horizontally by the substrate holding unit 35. A loading / unloading port 35 for the substrate W is formed on the side wall 32 b of the processing container 32. A gate valve 36 is provided at the loading / unloading port 35.

  An exhaust port 38 communicating with the exhaust pipe 37 is provided at the lower part of the processing container 32. The exhaust pipe 37 communicates with an exhaust means such as a pump, and the atmosphere in the processing container 32 is exhausted from the processing container 32 through the exhaust port 38.

  A vapor deposition source 41 is installed at the bottom of the processing container 32. The vapor deposition source 41 includes a container 41a that stores the vapor deposition material S and a heater 41b that heats the container 41a. The heater 41b heats the container 41a by supplying power from the power source 42 outside the processing container 32, and vaporizes or sublimates the vapor deposition material S. The vaporized or sublimated vapor deposition material S stays in the processing space 32a and is vapor deposited on the surface (lower surface) of the substrate W held by the substrate holding unit 35, so that a predetermined vapor deposition film is formed on the substrate surface.

  As shown in FIG. 3, the film thickness measuring apparatus 1 is attached to the substrate holding unit 35 in the vicinity of the substrate W. Thus, the film thickness of the vapor deposition film formed on the surface of the measurement unit 6 can be regarded as the film thickness of the vapor deposition film formed on the surface of the substrate W. The film thickness of the measurement unit 6 obtained through the signal processing device 11 and the processing device 12 is output to the control device 43 as the film thickness of the substrate W. The control device 43 can control the power source 42 based on the film thickness signal input in this manner, and for example, can control the ON / OFF of the power source and the temperature of the heater 41b.

  According to the vapor deposition apparatus 31 having such a configuration, it is possible to measure the film thickness of the vapor deposition film formed on the surface of the substrate W and the film formation rate (vapor deposition rate) in real time, and based on this, the vapor deposition source 41 can be measured. Thus, it is easy to form a film having a predetermined film thickness on the surface of the substrate W. Moreover, as described above, the maintenance cycle of the film thickness measuring device 1 is longer than that of the conventional one, so that the operation rate of the vapor deposition device 31 is improved. Furthermore, when compared with an optical film thickness measuring apparatus using a laser or the like conventionally used in this type of vapor deposition apparatus, the measurement accuracy is affected by the atmosphere in the processing vessel 32, for example, the optical system becomes dirty. In addition, it is possible to perform accurate measurement over a long period of time and to perform accurate film thickness control based on the measurement.

  Next, the vapor deposition apparatus concerning 2nd Embodiment using the film thickness measuring apparatus 1 is demonstrated. FIG. 4 shows an outline of the configuration of a vapor deposition apparatus 51 according to the second embodiment, and this vapor deposition apparatus 51 has a processing vessel 52 that forms a processing space 52a therein. A guide member 53 and a support member 54 that is moved along the guide member 53 by an appropriate drive source (not shown) are provided in the upper portion of the processing container 52. A substrate holding unit 55 such as an electrostatic chuck is attached to the support member 54, and the substrate W as a film formation target is held horizontally by the substrate holding unit 55. The peripheral edge of the substrate W is covered with a mask 56. A loading / unloading port 57 for the substrate W is formed in the side wall 32 b of the processing container 52. A gate valve 58 is provided at the loading / unloading port 57.

  An alignment device 59 is provided between the loading / unloading port 57 and the substrate holding unit 55. The alignment apparatus 59 includes a stage 59a that can move in the X, Y, Z, and θ directions, and the substrate W that has been loaded into the processing container 52 from the loading / unloading port 57 is first placed on the stage 59a. Therefore, after a predetermined alignment is performed, the stage 59a is raised so that the substrate W is delivered to the substrate holder 55.

  The vapor deposition apparatus 51 according to the present embodiment includes three vapor deposition sources 61, 62, and 63. Since both of them have the same configuration, for example, the vapor deposition source 61 will be described with reference to FIG. 5. An evaporation tray 61b for accommodating a vapor deposition material is provided at the lower part of the cylindrical main body 61a. A heater 61c is provided below the plate 61b. The heater 61c generates heat by supplying electric power from the power source 64 shown in FIG. 4, and can heat the evaporating dish 61b to a predetermined temperature. A protrusion 61e that forms a flow path 61d is provided on the upper portion of the main body 61a.

  Each flow path 61 d, 62 d, 63 d of each vapor deposition source 61, 62, 63 communicates with the guide path 65. A discharge port 66 is provided above one end of the guide path 65. The discharge port 66 is directed to the substrate W held by the substrate holding part 55. The discharge port 66 can be opened and closed by a damper 67. In the present embodiment, the damper 67 is configured to move up and down by, for example, a driving member 68 to close and open the discharge port 66. The driving member 68 and the power source 64 are controlled by a control device 69.

  In the present embodiment, the film thickness measuring device 1 is attached to the inner wall portion 66 a of the discharge port 66. The film thickness signal obtained through the film thickness measuring device 1, the signal processing device 11, and the processing device 12 is output to the control device 69. The control device 69 can control the power supply 64 based on the film thickness signal input in this manner, and can control the ON / OFF of the power supply 64 and the temperatures of the heaters 61c, 62c, and 63c, for example. The control device 69 controls the damper 67 via the drive member 68 based on the film thickness signal.

  As shown in FIG. 4, the atmosphere around the tip of the discharge port 66, together with the atmosphere in the processing container 52, as shown in FIG. The gas is exhausted to the outside of the processing container 52. The atmosphere in the induction path 65 is also exhausted from the exhaust port 77 to the outside of the processing vessel 52 through the exhaust path 76 below the damper 67.

  The vapor deposition apparatus 51 according to the present embodiment is configured as described above, and vapor deposition materials from the three vapor deposition sources 61, 62, and 63 pass through the respective flow paths 61d, 62d, and 63d through the guide path 65. The discharge port 66 discharges to the surface of the substrate W held by the substrate holding part 55, and a predetermined film is formed on the surface of the substrate W. Further, since the vapor deposition apparatus 51 includes three vapor deposition sources 61, 62, and 63, the vapors of the three types of vapor deposition materials corresponding to these are mixed in the induction path 65, and the three types of vapor deposition materials are mixed. A vapor deposition film can be formed on the surface of the substrate W.

  Since the film thickness measuring device 1 is attached to the inner wall 66a of the discharge port 66, it is possible to measure in real time the film thickness and film formation rate of the vapor deposition film in which the above three kinds of vapor deposition materials are mixed. In addition, it is easy to control the damper 67 based on this and form a film with a predetermined thickness on the surface of the substrate W. It is also possible to individually control the heaters 61c, 62c and 63c of the vapor deposition sources 61, 62 and 63 to control the mixing ratio of the three types of vapor deposition materials.

  Moreover, as described above, the maintenance cycle of the film thickness measuring device 1 is longer than that of the conventional one, so that the operating rate of the vapor deposition device 51 itself is improved. Of course, since the film thickness measuring apparatus 1 is not an optical film thickness measuring apparatus, it is possible to accurately measure over a long period of time and to perform accurate film thickness control based on the measurement.

  In order to control the mixing ratio of the three types of vapor deposition materials of the vapor deposition sources 61, 62, and 63 and the vapor deposition rate of each vapor deposition material independently and to control this, from each of the vapor deposition sources 61, 62, and 63, It is more preferable to independently measure and control the formation rate of the deposited film of the deposited material. For this purpose, for example, like the vapor deposition source 61 shown in FIG. 6, the film thickness measuring device 1 may be attached to the protrusion 61e and the vapor deposition rate of vapor of the vapor deposition material flowing in the flow path 61d may be measured.

  Then, a flow rate controller 61f for adjusting the flow rate of the vapor of the vapor deposition material flowing in the flow channel 61d may be provided in the flow channel 61d, and the flow rate controller 61 may be controlled by the controller 69 described above. By doing so, it is possible to control the flow rate of the vapor of the vapor deposition material flowing in the flow path 61d based on the measurement result of the vapor deposition rate due to the vapor of the vapor deposition material flowing in the flow path 61d. Of course, the heater 61c may be individually controlled based on the vapor deposition rate of the vapor flowing in the flow path 61d.

  Since the flow path 61d is close to the evaporating dish 61b and the heater 61c, a cooling device for cooling the film thickness measuring device 1 itself, for example, a Peltier element 61g may be provided in the film thickness measuring device 1 as necessary. Good.

  In addition, as shown in FIG. 7, the film thickness measuring device 1 is provided in the vicinity of the outlets of the flow paths 61 d, 62 d, 63 d of the respective vapor deposition sources 61, 62, 63, and from each vapor deposition source 61, 62, 63. The film formation rate may be measured.

  6 and 7, the film formation rate by the mixed vapor is measured even when the film formation rate from each vapor deposition source 61, 62, 63 is measured or controlled independently. As shown in FIG. 5, a method of controlling the damper 67 by providing the film thickness measuring device 1 at the discharge port 66 may be used in combination.

It is explanatory drawing which shows the outline of a structure of the film thickness measuring apparatus concerning embodiment. It is a graph which shows the change of the resonant frequency accompanying a film thickness change. It is explanatory drawing which shows the outline of a structure of the vapor deposition apparatus concerning 1st Embodiment. It is explanatory drawing which shows the outline of a structure of the vapor deposition apparatus concerning 2nd Embodiment. FIG. 5 is an enlarged explanatory view in the vicinity of a vapor deposition source in the vapor deposition apparatus of FIG. 4. It is explanatory drawing at the time of providing a film thickness measuring apparatus in a flow path. It is explanatory drawing at the time of providing a film thickness measuring apparatus in the exit of a flow path.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Film thickness measuring apparatus 2 Support part 3 AC power supply 4 Piezo element 5 Cantilever 6 Measuring part 7 Piezoresistive element 8 Heater 11 Signal processing apparatus 12 Processing apparatus 13 Storage apparatus 14 Arithmetic apparatus 31, 51 Vapor deposition apparatus

Claims (8)

A method for measuring the thickness of a film formed on a cantilever,
The resonance frequency is measured by vibrating the cantilever attached to the piezoelectric element by the piezoelectric element excited by the supply of AC power,
The film thickness of the film formed on the surface of the cantilever is obtained by comparing the measured resonance frequency with the relationship between the film thickness of the film formed on the cantilever and the resonance frequency of the cantilever which has been obtained in advance. A method for measuring film thickness. A device for measuring the thickness of a film formed on a cantilever,
A piezoelectric element that is excited by the supply of AC power;
A cantilever attached to the piezo element;
A piezoresistive element provided on the cantilever;
A film thickness measuring device comprising: an observation device for observing the vibration frequency of the cantilever based on the strain received by the piezoresistive element. A storage device storing the relationship between the film thickness of the film formed on the cantilever and the resonance frequency of the cantilever;
The film thickness measuring apparatus according to claim 2, further comprising an arithmetic unit that compares and collates the resonance frequency observed by the observation apparatus with data stored in the storage apparatus. The film thickness measuring device according to claim 2 or 3, further comprising a heater for heating the cantilever. An apparatus for depositing a deposition material on a substrate held in a processing vessel,
5. A vapor deposition apparatus, wherein the film thickness measuring apparatus according to claim 2 is disposed in a peripheral portion of the substrate. The vapor deposition according to claim 5, further comprising a control device that controls a vapor deposition source for vaporizing or sublimating the vapor deposition material based on the film thickness or the film formation rate measured by the film thickness measurement device. apparatus. An apparatus for depositing a deposition material on a substrate held in a processing vessel,
A vapor deposition source for vaporizing or sublimating the vapor deposition material accommodated in the accommodating portion;
A guide path for guiding vapor of the vapor deposition material generated from the vapor deposition source toward the substrate;
A discharge port for discharging the vapor from the guide path toward the substrate;
A damper for controlling the flow rate of vapor of the vapor deposition material discharged from the discharge port through the guide path;
The film thickness measuring device according to any one of claims 2 to 4, provided at the discharge port,
The vapor deposition apparatus further comprising a control device for controlling the damper based on a film thickness or a film formation rate measured by the film thickness measuring apparatus. An apparatus for depositing a deposition material on a substrate held in a processing vessel,
A vapor deposition source for vaporizing or sublimating the vapor deposition material accommodated in the accommodating portion;
A guide path for guiding vapor of the vapor deposition material generated from the vapor deposition source toward the substrate;
A discharge port for discharging the vapor from the guide path toward the substrate;
The film thickness measuring device according to any one of claims 2 to 4, provided in a flow path leading to the guide path in the vapor deposition source,
A flow regulator for controlling the flow rate of vapor of the vapor deposition material passing through the flow path;
The vapor deposition apparatus further comprising a control device that controls the flow rate regulator based on a film thickness or a film formation rate measured by the film thickness measurement device.

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