JP4642212B2 - Vacuum processing apparatus and vacuum processing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vacuum processing apparatus and a vacuum processing method, and more particularly to improvement of a technique for forming or etching a thin film on a substrate while measuring the thickness of the thin film.
[0002]
[Prior art]
Reference numeral 110 in FIG. 6 shows a conventional sputtering apparatus. The vacuum processing apparatus 110 has a vacuum chamber 111. The vacuum chamber 111 is provided with an exhaust port 118 connected to a vacuum exhaust system (not shown). When the vacuum exhaust system is driven, the inside of the vacuum chamber 111 can be evacuated.
[0003]
The vacuum chamber 111 is provided with a gas introduction port 117 connected to a gas introduction system (not shown), and is configured so that gas can be introduced into the vacuum chamber 111 from the gas introduction port 117.
[0004]
A backing plate 112 is disposed on the ceiling of the vacuum chamber 111, and a target 113 made of a metal material is disposed on the side of the backing plate 112 facing the inside of the vacuum chamber 111.
[0005]
A mounting table 115 is disposed on the inner bottom surface of the vacuum chamber 111 so as to face the target 113. The surface of the mounting table 115 is flat, and is configured so that a substrate described later can be mounted on the surface.
Further, a crystal oscillator 180 is disposed above the mounting table 115 inside the vacuum chamber 111.
[0006]
On the other hand, a DC power source 114 and a measuring device 190 are provided outside the vacuum chamber 111. Among these, the DC power source 114 is connected to the backing plate 112, and is configured such that when the DC power source 114 is activated, a DC voltage can be applied to the target 113 via the backing plate 112.
The measuring device 190 is connected to the crystal oscillator 180, and is configured to oscillate the crystal oscillator 180 and detect the oscillation frequency.
[0007]
In order to form a metal thin film on the silicon substrate surface by sputtering using the sputtering apparatus 110 having such a configuration, first, the inside of the vacuum chamber 111 is evacuated and the substrate 120 is placed in the vacuum chamber 111 while maintaining the vacuum state. And is placed on the surface of the mounting table 115.
[0008]
Next, when electric power is supplied to the target 113 while introducing a certain amount of sputtering gas such as argon gas from the gas introduction port 117, discharge occurs. The above-described deposition preventing plate 119 is grounded, and as a result, discharge occurs only in the vicinity of the target in the vacuum chamber 111.
[0009]
When discharge occurs, the target 113 is sputtered. At this time, the sputtered target material jumps out in the direction of the surface of the substrate 120 and also in the direction of the inner side surface and the inner bottom surface of the vacuum chamber 111. Since the deposition preventing plate 119 having a circular opening is provided, the sputtered target material does not directly adhere to the inner bottom surface and the inner side surface around the mounting table 115 of the vacuum chamber 111, and It adheres only to the surface and the crystal oscillator 180.
[0010]
In this way, a thin film is formed on the surface of the substrate 120 by attaching the target material to the surface of the substrate 120. The target material also adheres to the crystal oscillator 180, and a thin film is formed on the surface thereof.
[0011]
The oscillation frequency of the crystal oscillator 180 changes according to the thickness of the thin film attached to the surface of the crystal oscillator 180. The measuring device 190 detects the change in the oscillation frequency and obtains the film thickness of the thin film formed on the crystal oscillator 180. Since the film thickness of the thin film formed on the crystal oscillator 180 has a correlation with the film thickness of the thin film formed on the surface of the substrate 120, the film was formed on the crystal oscillator 180 in the above-described apparatus. The film thickness of the thin film formed on the surface of the substrate 120 is obtained from the film thickness of the thin film.
[0012]
In the above apparatus, the film thickness of the thin film formed on the substrate surface is obtained while performing the film formation process as described above, and when the obtained film thickness reaches a predetermined value, the film formation process is terminated. Compared with the case where the thickness of the thin film is managed by the time of the film forming process, the thickness of the thin film actually formed becomes close to a predetermined value.
[0013]
However, in the above-described apparatus, the crystal oscillator must be positioned at an upper position away from the substrate surface so as not to interfere with film formation. For this reason, the distance between the crystal oscillator and the target is different from the distance between the substrate surface and the target, and the film thickness of the thin film attached to the crystal oscillator and the film thickness of the thin film formed on the substrate surface are different. There was a big difference. Therefore, the film thickness of the thin film formed on the substrate surface could not be measured accurately.
Further, when a film having a thickness greater than that of the crystal oscillator is formed, there is a big problem that the crystal oscillator must be replaced.
[0014]
[Problems to be solved by the invention]
The present invention was created to solve the above-described disadvantages of the prior art, and an object of the present invention is to provide a technique that can accurately determine the thickness of a thin film formed on the surface of a substrate. .
[0015]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is a vacuum processing apparatus, which is arranged in a vacuum chamber and the vacuum chamber, and can hold the substrate in a state where the substrate is in contact with the surface. A substrate holding body configured in the above, a measurement coil disposed in the substrate holding body so as to be positioned in the vicinity of the surface of the substrate holding body, and supplying an electric current to the measurement coil to generate an eddy current in the substrate. Current supply means for generating, and measurement means for measuring a signal generated in the measurement coil by the eddy current.
A second aspect of the present invention is the vacuum processing apparatus according to the first aspect, wherein the substrate is connected in series to the measurement coil, and the substrate holder holds the substrate. A measurement coil connected in series with two reference resistors connected in parallel with the reference coil, and the measurement means is connected to the measurement coil and the reference coil. And measuring a potential difference between the two reference resistors and a portion where the two reference resistors are connected to each other as a signal generated in the measurement coil.
Invention of Claim 3 is a vacuum processing apparatus of Claim 1 or Claim 2, Comprising: It is a thin film on the surface of the said board | substrate in the state in which the said board | substrate holding body hold | maintained the said board | substrate in the said vacuum chamber. A processing means for forming a film is provided.
Invention of Claim 4 is the vacuum processing apparatus of Claim 1 or Claim 2, Comprising: It forms in the surface of the said board | substrate in the state in which the said board | substrate holding body hold | maintained the said board | substrate in the said vacuum chamber. And a processing means for etching the formed thin film.
The invention according to claim 5 is a vacuum processing method configured to measure a film thickness of a conductive thin film formed on the substrate surface while processing the substrate surface in a vacuum atmosphere. A coil is arranged on the back side of the substrate, current is supplied to the measurement coil, eddy current is generated inside the substrate, a signal generated in the measurement coil is detected by the eddy current, and from the signal, The thickness of the thin film formed on the substrate surface is obtained.
A sixth aspect of the present invention is the vacuum processing method according to the fifth aspect, wherein a conductive thin film is formed on the substrate surface as the treatment of the substrate surface.
A seventh aspect of the present invention is the vacuum processing method according to the fifth aspect, wherein the conductive thin film formed on the substrate surface is etched as the treatment of the substrate surface.
Invention of Claim 8 is the vacuum processing method of any one of Claim 5 thru | or 7, Comprising: The reference coil is arrange | positioned in the position far from the said measurement coil with respect to the said board | substrate, and said measurement A Maxwell inductance bridge is configured using the coil and the reference coil, and a change in the inductance component of the measurement coil is obtained using the Maxwell inductance bridge to detect a signal generated in the measurement coil. It is characterized by.
The invention according to claim 9 is a vacuum processing method, wherein the film thickness of the thin film formed on the substrate surface is determined by the vacuum processing method according to any one of claims 5 to 8. The film thickness is compared with a predetermined value set in advance, and when the obtained film thickness matches the predetermined value, the vacuum processing of the thin film is terminated.
[0016]
The present invention is configured as described above, and the measurement coil is positioned in the vicinity of the substrate, an AC voltage is applied to the measurement coil to generate an eddy current in the substrate, and the measurement is influenced by the eddy current generated in the substrate. The thickness of the thin film formed on the substrate surface is obtained by obtaining a change amount of a signal generated in the coil, for example, an inductance component.
[0017]
The amount of change in the inductance component of the measurement coil is obtained by a high sensitivity measurement circuit using an inductance bridge.
FIG. 4 is a block diagram for explaining the measurement principle of the present invention. Reference numeral 70 denotes a Maxwell inductance bridge.
[0018]
The inductance bridge 70 includes two reference resistors 71 and 72 connected in series, and a reference coil 73 and a measurement coil 31 connected in series.
[0019]
When the inductance bridge 70 is balanced, an AC voltage source 75 is connected between the input terminals 76 and 77, and the AC voltage V is connected to the inductance bridge 70. _D Does not appear between the output terminals 78 and 79.
[0020]
When the substrate 23 is brought close to the measurement coil 31 in a state where the inductance bridge 70 is balanced, an eddy current is generated in the substrate 23, and the inductance value of the measurement coil 31 is changed due to the influence, and the balance is lost and the output terminal 78, Voltage V between 79 _S Appears.
[0021]
AC voltage V applied to inductance bridge 70 _D The
V _D = V _D0 ・ Exp (iωt)
In this case, the voltage V appearing between the output terminals 78 and 79 _S Is
[0022]
V _S = V _S0 ・ Exp (iωt + φ) = V _S0 ・ Exp (iωt) ・ cos (φ) + i ・ V _S0 ・ Exp (iωt) ・ sin (φ)
It becomes.
[0023]
This voltage V _S Input voltage V _D A voltage having a phase synchronized with the voltage and a voltage having a phase shifted by 90 ° are measured, and a change in the magnitude of the inductance component of the measurement coil 31 is obtained from the ratio.
[0024]
The amount of change in the inductance component represents eddy current loss in the substrate 23, and the AC voltage V _D Therefore, if the specific resistance of the substrate 23 or the metal thin film on the surface of the substrate 23 is known, the film thickness of the metal thin film is required.
[0025]
The graph of FIG. 5 is a graph showing an example of the relationship between the change amount of the inductance component and the film thickness of the copper thin film on the substrate surface. The frequency of the applied AC signal is 2 MHz.
AC voltage V _D Is about several volts, and the alternating magnetic field is about 10 gauss.
[0026]
As can be seen from this graph, since the amount of change in the inductance component of the measurement coil changes according to the film thickness of the copper thin film on the substrate surface, the relationship between the amount of change in the inductance component and the film thickness is measured in advance. Measure the amount of change in the inductance component by bringing the substrate closer to the measurement coil before actually forming the film, and then determine the amount of change in the inductance component of the measurement coil by moving the substrate in the middle of the film closer to the measurement coil. The film thickness of the formed thin film can be obtained from the obtained change amount of the inductance component.
[0027]
Thus, in the present invention, an eddy current is generated in the substrate by the measurement coil, and the film thickness of the thin film is obtained in accordance with the amount of change in the inductance component of the measurement coil due to the eddy current. The actual film thickness can be obtained more accurately than in the prior art in which the quartz crystal resonator is disposed above the substrate and the change in the oscillation frequency is detected.
[0028]
Moreover, in this invention, it is comprised so that a measurement coil may be located in the back surface side of a board | substrate. The deposition material reaches the surface of the substrate, but the measurement coil is behind the substrate, and the deposition material does not reach the measurement coil. In addition, there is no problem of lifetime due to film adhesion.
[0029]
Note that when a thin film is formed on the surface of the substrate, a sputtering method, a CVD method, or an evaporation method may be used.
Further, in the present invention, the film thickness of the thin film is obtained while forming a film on the surface of the substrate, the obtained film thickness of the thin film is compared with a predetermined value, and the obtained film thickness matches the predetermined value. The thin film formation is finished.
[0030]
At this time, since the film thickness can be obtained more accurately than in the conventional case where the film thickness is obtained using a crystal oscillator or the like, a film closer to a desired value when the film formation process is completed. A thin film can be formed to be thick.
[0031]
In addition to the film formation process, the substrate surface process may be an etching process. In this case, the thin film formed in advance on the substrate surface is etched, and the thickness of the thin film is accurately measured. Since the etching can be terminated when the obtained film thickness becomes zero, it is more accurate than the conventional case where the end point is detected by, for example, time management or etching product detection. The end point can be detected.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
Reference numeral 10 in FIG. 1 shows a sputtering apparatus according to an embodiment of the present invention. The vacuum processing apparatus 10 has a vacuum chamber 11.
The vacuum chamber 11 is provided with an exhaust port 18. The exhaust port 18 is connected to an unillustrated evacuation system, and is configured such that when the evacuation system is driven, the inside of the vacuum chamber 11 can be evacuated.
[0033]
The vacuum chamber 11 is provided with a gas inlet 17. The gas introduction port 17 is connected to a gas introduction system (not shown), and is configured such that gas can be introduced into the vacuum chamber 11 from the gas introduction port 17.
[0034]
A backing plate 12 is disposed on the ceiling of the vacuum chamber 11, and a target 13 made of a metal material is disposed on the side of the backing plate 12 facing the inside of the vacuum chamber 11. Here, the target 13 is made of copper.
[0035]
A DC power source 14 is provided outside the vacuum chamber 11. The DC power supply 14 is connected to the backing plate 12, and is configured to supply a DC voltage to the target 13 through the backing plate 12 when the DC power supply 14 is activated.
[0036]
A mounting table 15 is disposed on the inner bottom surface of the vacuum chamber 11 so as to face the target 13. The mounting table 15 is an example of a substrate holder and is made of an insulator. The surface of the mounting table 15 is flat.
[0037]
In the mounting table 15, an electrostatic adsorption electrode 82 connected to a DC power source (not shown). ₁ , 82 ₂ Is embedded, and the electrostatic adsorption electrode 82 is mounted with the substrate placed on the surface. ₁ , 82 ₂ When a DC voltage is applied between them, the substrate can be electrostatically attracted. In addition, a heating device 83 is provided in the mounting table 15 so that the substrate can be heated while electrostatically attracting the substrate.
[0038]
Further, a hole 93 is provided on the surface of the mounting table 15. A detection unit 81 is disposed in the hole 93.
As shown in FIG. 1, the detection unit 81 includes a support body 80, a measurement coil 31, and a reference coil 73. Among these, the support body 80 is arrange | positioned in the hole 93 of the mounting base 15 mentioned above. The support 80 has a hole 95 therein, and the measurement coil 31 and the reference coil 73 are provided in the hole 95. As described above, since the measurement coil 31 and the reference coil 73 are included in the support body 80, the temperature environment of both coils becomes the same, and accurate measurement is possible.
[0039]
The measurement coil 31 is disposed in the hole 95 of the support 80 so that the measurement coil 31 is positioned in the vicinity of the surface of the mount 15 in a state where the support 80 is disposed in the hole 93 on the surface of the mount 15. The reference coil 73 is disposed in the hole 95 of the support body 80 so as to be positioned farther than the measurement coil 31 with respect to the surface of the mounting table 15. The measurement coil 31 and the reference coil 73 are connected in series and connected to the measurement device 90.
[0040]
The measuring device 90 includes two reference resistors 71 and 72, a measuring instrument 91, and an AC voltage source 75 that are arranged outside the vacuum chamber 11 and connected in series.
The two reference resistors 71 and 72 connected in series are connected in parallel to the measurement coil 31 and the reference coil 73 in the detection unit 81 that are also connected in series, and together with the measurement coil 31 and the reference coil 73, FIG. The Maxwell inductance bridge 70 described in FIG.
[0041]
Both ends of the reference resistors 71 and 72 connected in series are input terminals of the inductance bridge 70, and an AC voltage source 75 is connected to them, and when the AC voltage source 75 is activated, an AC current is supplied to the measurement coil 31. It is comprised so that it can supply.
[0042]
In the inductance bridge 70, a portion where the measurement coil 31 and the reference coil 73 are connected and a portion where the two reference resistors 71 and 72 are connected to each other are output terminals of the inductance bridge 70. In FIG. 1, the output terminals are denoted by reference numerals 78 and 79, respectively.
[0043]
A measuring instrument 91 is connected between the output terminals 78 and 79 of the inductance bridge 70, and the amount of change in the inductance component of the measuring coil 31 is obtained by measuring the voltage appearing between the output terminals 78 and 79. It is configured to be able to.
[0044]
In the sputtering apparatus 10 having the above-described configuration, the inductance bridge is balanced and the voltage appearing between the output terminals 78 and 79 of the inductance bridge is set to 0 in a state where the substrate is not mounted on the mounting table 15 in advance.
[0045]
Then, the AC voltage source 75 is activated to supply an AC current to the measurement coil 31 in a state where a substrate of the same type and the same thickness as the substrate 23 to be measured is mounted on the mounting table 15.
[0046]
As a result, an alternating magnetic field is formed in the measurement coil 31 and in the space in the vicinity thereof.
This alternating magnetic field reaches the substrate 23 located in the vicinity of the measuring coil 31, and an eddy current is generated inside the substrate 23. Due to this eddy current, the balance of the inductance bridge is lost, and a voltage is generated between the output terminals 78 and 79 of the inductance bridge. The measuring device 91 measures the voltage, whereby the amount of change in the inductance component of the measuring coil 31 can be obtained.
[0047]
Prior to the actual film forming process, the thickness of the known thin film formed on the substrate surface and the amount of change in the inductance component of the measuring coil 31 are measured in advance for a substrate of the same type and thickness as the substrate 23 to be measured. And the obtained correspondence relationship is stored in the measuring device 91.
[0048]
In order to form a metal thin film on the surface of the substrate 23 made of a semiconductor such as silicon by using the sputtering apparatus 10 having such a configuration, first, the inside of the vacuum chamber 11 is evacuated and the vacuum state is maintained. A substrate 23 made of silicon or the like is carried into the vacuum chamber 11 and mounted on the surface of the mounting table 15. In this state, the electrostatic adsorption electrode 82 ₁ , 82 ₂ A DC voltage is applied between them to electrostatically attract the substrate 23. The mounting table 15 is heated in advance by the heating device 83, and the temperature of the substrate 23 is increased.
[0049]
When the substrate 23 is heated to a predetermined temperature, the AC voltage source 75 is activated to supply current to the measurement coil 31, and the amount of change in the inductance component of the measurement coil 31 when no thin film is formed is obtained. Keep it.
[0050]
Next, when electric power is supplied to the target 13 while introducing a certain amount of sputtering gas such as argon gas from the gas introduction port 17, discharge occurs. The above-described deposition preventing plate 19 is grounded, and as a result, discharge is generated only in the vicinity of the target in the vacuum chamber 11.
[0051]
When discharge occurs, the target 13 is sputtered. At this time, the sputtered target material jumps out in the direction of the surface of the substrate 23 and also in the direction of the inner side surface and the inner bottom surface of the vacuum chamber 11. Since the deposition preventing plate 19 having a circular opening is provided, the sputtered target material does not directly adhere to the inner bottom surface or the inner side surface around the mounting table 15 of the vacuum chamber 11. A metal thin film is formed on the surface of the substrate 23 by the target material thus reaching the surface of the substrate 23.
[0052]
The measuring device 91 constantly obtains the amount of change in the inductance component of the measuring coil 31 while sputtering a target to form a thin film on the surface of the substrate 23. The amount of change in the inductance component of the measuring coil 31 changes according to the thickness of the thin film. As described above, the measuring device 91 stores the correspondence relationship between the change amount of the inductance component and the film thickness of the substrate of the same type and the same thickness as the substrate 23 to be measured, and the thin film is formed. Taking the difference between the amount of change in the inductance component at the time and the amount of change in the inductance component when the thin film is not formed, and comparing this difference with the above-described correspondence, the film thickness of the thin film is obtained. be able to.
[0053]
In this way, the film forming process is continued while obtaining the thin film thickness, and the discharge is stopped when the obtained change amount of the inductance component reaches a predetermined value, that is, when the thin film thickness reaches the predetermined value. Then, the film forming process is terminated.
[0054]
In the present embodiment, as described above, an eddy current is passed through the substrate to be measured, and the film thickness of the thin film is obtained by detecting the amount of change in the inductance component of the measurement coil 31 that changes according to the eddy current. Therefore, compared to the conventional case where a crystal oscillator is disposed at a position away from the substrate and the thickness of the thin film formed on the substrate surface is determined according to the thickness of the thin film formed on the crystal oscillator. Thus, the obtained film thickness becomes a value close to the film thickness of the actually formed thin film, and the film thickness can be obtained more accurately than in the past.
[0055]
When the film forming process for one substrate 23 is completed through the above steps, the substrate 23 for which the film forming process has been completed is taken out of the vacuum chamber 11, and a new substrate is carried into the vacuum chamber 11 to be loaded. Place on the surface of the mounting table 15.
[0056]
Next, before the film formation process, the amount of change in the inductance component of the measuring coil 31 is measured in a state where the new substrate is placed. Thereafter, the same process as described above is performed, and the new substrate surface is obtained. The film thickness of the thin film is obtained by obtaining the amount of change in the inductance component while forming the thin film on the substrate. When the film thickness thus obtained reaches a predetermined value, by repeating the film forming process, a thin film can be formed on the surface of a plurality of substrates, and the accurate film thickness can be measured.
[0057]
Further, the measurement coil 31 is disposed in the mounting table 15 and is located on the back side of the substrate 23. Therefore, although the target material reaches the surface of the substrate 23, the film formation substance or the like does not adhere to the measurement coil 31 because the substrate 23 is shaded. Therefore, the target material adheres to the measurement coil 31, and problems such as a decrease in measurement accuracy do not occur.
[0058]
In the above-described embodiment, the sputtering apparatus has been described as the vacuum processing apparatus of the present invention. However, the vacuum processing apparatus of the present invention is not limited to this, and for example, the configuration is shown by reference numeral 30 in FIG. A CVD apparatus may be used.
[0059]
The CVD apparatus 30 has a vacuum chamber 32. An evacuation system 41 is provided outside the vacuum chamber 32, and is configured such that when the evacuation system 41 is activated, the inside of the vacuum chamber 32 can be evacuated.
[0060]
An electrode 38 is provided on the ceiling side of the vacuum chamber 32 while being electrically insulated from the vacuum chamber 32.
On the other hand, a voltage source 40 is disposed outside the vacuum chamber 32 so that a high-frequency voltage can be applied to the electrode 38 with the vacuum chamber 32 placed at the ground potential.
[0061]
A mounting table 37 made of an insulator is disposed on the bottom wall inside the vacuum chamber 32. The mounting table 37 is an example of a substrate holder, and the surface thereof is flattened so that the substrate can be mounted thereon. In the mounting table 37, the above-described electrostatic chucking electrode 82 is provided. ₁ , 82 ₂ And a heating device 83 are embedded, and the substrate is electrostatically adsorbed on the surface, and the temperature of the substrate can be raised in this state. Further, instead of electrostatic attraction, a vacuum chuck method may be used.
[0062]
A hole is provided in the surface of the mounting table 37, and the detection unit 81 described above with reference to FIG. 1 is disposed in the hole. The detection unit 81 is connected to a measuring device 90 disposed outside the vacuum chamber 32.
[0063]
The electrode 38 includes an electrode body 33 and a shower plate 36. The electrode body 33 is formed in a container shape, and one end of a gas introduction pipe 39 is connected to the bottom surface portion of the container. A gas cylinder (not shown) is connected to the other end of the gas introduction pipe 39 so that the gas can be introduced into the container-like space of the electrode body 33.
[0064]
The shower plate 36 is fixed so as to close the container opening of the electrode main body 33, and a space is formed by the electrode main body 33 and the shower plate 36.
A large number of holes 35 are formed in the shower plate 36. When gas is introduced into the space from the gas introduction pipe 39, this space becomes the gas storage chamber 34, and the introduced gas is once filled, and then , Each hole 35 can be blown out into the vacuum chamber 32.
[0065]
Outside the vacuum chamber 32, the measuring device 90 described in FIG. The measuring device 90 is connected to the detection unit 81 and is configured to measure the amount of change in the inductance component of the measurement coil 31 inside the detection unit 81.
[0066]
When a metal thin film such as a copper thin film is formed on the surface of the substrate 23 by the CVD method using the CVD apparatus 30 having such a configuration, first, the vacuum chamber 32 is evacuated by the evacuation system 41 and heated. The apparatus 83 is activated to raise the temperature of the mounting table 37. When the pressure in the vacuum chamber 32 reaches a predetermined pressure and the mounting table 37 is heated to a predetermined temperature, the substrate 23 is loaded into the vacuum chamber 32 and maintained on the mounting table 37 while maintaining the vacuum state. Then, the substrate 23 is electrostatically attracted to the surface of the mounting table 37.
[0067]
When the substrate 23 is heated to a predetermined temperature, the source gas is introduced into the gas storage chamber 34 and sprayed from the shower plate 36 onto the surface of the substrate 23.
In this state, the voltage source 40 is started and a high-frequency AC voltage is applied to the electrode 38 to generate a discharge. Plasma is generated by the discharge, the source gas is decomposed, and vapor growth is performed on the surface of the substrate 23. A copper thin film is formed on the surface 23. Of course, some source gases do not require the assistance of plasma, and in this case, the film can be formed only by thermal decomposition without starting up the voltage source 40.
[0068]
Also in the CVD apparatus 30, as in the sputtering apparatus 10 of FIG. 1, during the film forming process, the measuring apparatus 90 is formed by determining the amount of change in the inductance component of the measuring coil 31 due to the eddy current in the substrate 23. The thickness of the thin film is measured.
For this reason, as with the sputtering apparatus 10, the film forming process can be performed while obtaining an accurate film thickness as compared with the conventional case.
In this way, the film forming process is performed, and when the film thickness obtained more accurately than the conventional one reaches a predetermined value, the supply of the source gas and the application of the AC voltage are stopped, and the film forming process is terminated.
[0069]
Furthermore, the vacuum processing apparatus of the present invention is not limited to the sputtering apparatus 10 and the CVD apparatus 30 described above, and may be, for example, a vacuum evaporation apparatus as described later.
An example of the vacuum evaporation apparatus which is other embodiment of this invention is shown to the code | symbol 50 of FIG. The vacuum deposition apparatus 50 includes a vacuum chamber 51, an evaporation source 54, and a substrate holder 55.
[0070]
The evaporation source 54 is disposed on the inner bottom surface of the vacuum chamber 51, and a metal material 53 is disposed therein. An electron gun 56 is disposed on the side of the evaporation source 54. When the electron beam 56 is irradiated onto the metal material 53 from the electron gun 56, the metal material 53 is heated and evaporated, and the vapor in the vacuum chamber 51. It is comprised so that it may be made to discharge | release.
A substrate holder 55 made of an insulator is disposed above the evaporation source 54. The substrate holder 55 is an example of a substrate holder, and the electrostatic adsorption electrode 82 described above is included in the substrate holder 55. ₁ , 82 ₂ And the heating device 83 are embedded so that the substrate can be electrostatically adsorbed and held with the back surface of the substrate in contact with the front surface and the substrate surface facing downward.
Further, a hole (not shown) is provided in the vicinity of the surface of the substrate holder 55, and the detection unit 81 described with reference to FIG. 1 is disposed in the hole.
[0071]
In order to form a thin film by a vapor deposition method on the substrate surface with such a vacuum vapor deposition apparatus, the substrate 23 is held in advance by the substrate holder 55, the surface of the substrate 23 is opposed to the evaporation source 54, and a vacuum exhaust system (not shown). The evaporation material is evaporated from the evaporation source 54 while the vacuum chamber 51 is evacuated. Then, the evaporated vapor deposition material reaches the surface of the substrate 23, and a thin film made of the vapor deposition material is formed on the surface of the substrate 23.
[0072]
In the vacuum vapor deposition apparatus 50 as well as the sputtering apparatus 10 in FIG. 1 and the CVD apparatus 30 in FIG. 23, during the film forming process, the measurement apparatus 90 performs the inductance component of the measurement coil 31 due to the eddy current generated in the substrate. Since the change amount is obtained and the film thickness of the formed thin film is measured, the film formation process can be performed while obtaining an accurate film thickness as compared with the conventional case.
When the thickness of the metal thin film thus formed on the surface of the substrate 23 reaches a predetermined value, the electron beam irradiation is terminated and the film deposition process is terminated.
[0073]
In each of the embodiments described above, an apparatus for measuring the thickness of a thin film while forming a thin film on the surface of the substrate 23 has been described. However, the present invention is not limited to this, and for example, The thickness of the thin film may be measured while etching the thin film already formed on the substrate surface.
[0074]
One example will be described below. As an etching apparatus, an apparatus having the same configuration as the CVD apparatus 30 described in FIG. 2 is used. First, a substrate on which a metal thin film has been formed in advance is carried into the vacuum chamber 32 and placed on the surface of the mounting table 37. In this state, an electric current is supplied to the measurement coil 31 to cause an eddy current in the substrate, and the amount of change in the inductance component before the start of etching due to the eddy current is obtained.
[0075]
Next, when a fluorine-based etching gas is introduced from the gas inlet 39 and sprayed from the shower plate 36 to the surface of the substrate 23, the voltage source 40 is activated in this state, and a high-frequency AC voltage is applied to the electrode 38. Discharge occurs, plasma is generated by the discharge, and the etching gas is decomposed, whereby the thin film on the substrate surface is etched.
[0076]
During this etching process, the measuring device 90 always operates and obtains the amount of change in the inductance component of the measuring coil 31 due to the eddy current in the substrate 23. By obtaining the difference between the amount of change thus obtained and the amount of change of the inductance component before the start of etching, the film thickness of the thin film on the substrate surface can be accurately obtained as in the above-described embodiment.
[0077]
In this way, the thickness of the thin film is obtained while etching, and when the thin film thickness reaches 0, the etching is terminated, thereby making it possible to detect the end point by detecting time control and reaction products. The end point can be accurately detected.
[0078]
In each of the above-described embodiments, the reference resistors 71 and 72 constituting the inductance bridge 70 are provided inside the measuring device 90, but the present invention is not limited to this, and these reference resistors 71 and 72 may be arranged inside the detection unit 81.
[0079]
Moreover, in each embodiment mentioned above, although the measuring device 91 is comprised so that the variation | change_quantity of the inductance component of the measurement coil 31 may always be measured, this invention is not limited to this, and it is intermittent at a predetermined time interval. You may comprise so that it may measure in multiple times.
[0080]
Further, in each of the embodiments described above, the amount of change in the inductance component of the measurement coil 31 is measured using Maxwell's inductance bridge, but the present invention is not limited to this, and the amount of change in the inductance component of the measurement coil 31 is measured. Any device may be used as long as it is a high-precision measuring device capable of measuring.
[0081]
Further, in each of the above-described embodiments, the mounting tables 15 and 37 and the substrate holder 55 which are substrate holders are both electrostatically attracting electrodes 82. ₁ , 82 ₂ However, the substrate holder of the present invention is not limited to this, and is configured to hold the substrate like a vacuum chuck. Just do it. However, when the substrate is electrostatically adsorbed, the entire surface of the substrate is in close contact with the substrate holder, so that good measurement reproducibility can be obtained. Therefore, a substrate holder having a configuration capable of electrostatic adsorption as in the present embodiment is preferable.
Furthermore, it is also possible to arrange a plurality of detectors 81 of the present invention on the surface of the mounting table 15 and measure the film thickness distribution.
[0082]
【The invention's effect】
While the thin film is formed on the substrate surface, the film thickness of the thin film can be accurately obtained.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a vacuum processing apparatus according to a first example of the present invention.
FIG. 2 is a diagram illustrating a vacuum processing apparatus according to a second example of the present invention.
FIG. 3 is a diagram illustrating a vacuum processing apparatus according to a third example of the present invention.
FIG. 4 is a diagram for explaining the measurement principle of the present invention.
FIG. 5 is a graph showing an example of the relationship between the film thickness and the amount of change in inductance component;
FIG. 6 is a diagram for explaining a conventional vacuum processing apparatus.
[Explanation of symbols]
10 …… Sputtering equipment (vacuum processing equipment)
11, 32, 51 ... Vacuum chamber
13 ... Sputtering target (processing means)
15, 37 ... Mounting table (substrate holder)
31 …… Measurement coil
38 …… Electrodes (treatment means)
55 …… Substrate holder (substrate holder)
54 …… Vapor deposition source (processing means)
73 …… Reference coil
75 …… AC voltage source (current supply means)
90 …… Measurement equipment

Claims (9)

A vacuum chamber;
A substrate holder arranged in the vacuum chamber and configured to hold the substrate in a state where the substrate is in contact with the surface;
A measurement coil disposed in the substrate holder so as to be located near the surface of the substrate holder;
Current supply means for supplying current to the measurement coil to generate eddy current inside the substrate;
A vacuum processing apparatus comprising: a measuring unit that measures a signal generated in the measuring coil by the eddy current. A reference coil that is connected in series to the measurement coil and is disposed farther than the measurement coil with respect to the substrate in a state where the substrate holder holds the substrate;
A measurement coil connected in series and two reference resistors connected in parallel with the reference coil;
The measurement means is configured to measure a potential difference between a portion where the measurement coil and the reference coil are connected and a portion where the two reference resistors are connected to each other as a signal generated in the measurement coil. The vacuum processing apparatus according to claim 1. The vacuum processing apparatus according to claim 1 or 2,
A vacuum processing apparatus, wherein a processing means for forming a thin film on the surface of the substrate in a state where the substrate holder holds the substrate is provided in the vacuum chamber. The vacuum processing apparatus according to claim 1 or 2,
A vacuum processing apparatus, wherein a processing means for etching a thin film formed on a surface of the substrate is provided in the vacuum chamber in a state where the substrate holder holds the substrate. A vacuum processing method configured to measure a film thickness of a conductive thin film formed on the substrate surface while processing the substrate surface in a vacuum atmosphere,
Place the measuring coil on the back side of the substrate,
Supplying current to the measuring coil to generate eddy current inside the substrate;
A vacuum processing method, wherein a signal generated in the measurement coil is detected by the eddy current, and a film thickness of a thin film formed on the substrate surface is obtained from the signal. 6. The vacuum processing method according to claim 5, wherein a conductive thin film is formed on the surface of the substrate as the surface of the substrate. 6. The vacuum processing method according to claim 5, wherein the conductive thin film formed on the substrate surface is etched as the substrate surface treatment. A reference coil is disposed at a position farther than the measurement coil with respect to the substrate, and a Maxwell inductance bridge is configured using the measurement coil and the reference coil.
8. The signal generated in the measurement coil is detected by obtaining a change in an inductance component of the measurement coil by using the Maxwell inductance bridge. 8. Vacuum processing method. The film thickness of the thin film formed on the substrate surface is determined by the vacuum processing method according to any one of claims 5 to 8, and the determined film thickness is compared with a predetermined value set in advance. A vacuum processing method for ending the vacuum processing of the thin film when the determined film thickness matches the predetermined value.

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