JP2013167007A - Multi-source deposition apparatus - Google Patents

Abstract

【Task】
An object of the present invention is to provide a multi-source deposition apparatus capable of controlling the composition ratio of a thin film composed of a plurality of elements deposited on a substrate more accurately than in the past.
[Solution]
The film thickness sensor used in the multi-source vapor deposition apparatus has a detection surface capable of detecting the film thickness of the vapor deposition material to be deposited, and is arranged so that the detection surface faces the evaporation source of the vapor deposition material to be detected. Between the detection unit, the barrier unit surrounding the detection surface and extending toward the evaporation source of the vapor deposition material to be detected, and the evaporation unit of the vapor deposition material to be detected and the barrier unit And a heating part having a shape that does not overlap the detection surface but overlaps the barrier part when viewed from the evaporation source.
[Selection] Figure 4

Description

  The present invention relates to a multi-source deposition apparatus for depositing a thin film composed of a plurality of elements on a substrate, and more particularly to a film thickness sensor used in the multi-element deposition apparatus.

_{PZT [Pb (Zr x Ti 1} -x) O 3] or _{PLZT [(Pb 1-x La} x) (Zr y Ti 1-y) 1-x / 4 O 3] multi-component oxides typified by Ferroelectric materials have excellent piezoelectricity, pyroelectricity, electro-optical properties, etc., and are applied to various electronic devices. Such a multi-element oxide ferroelectric can be formed on a substrate by using, for example, a sputtering method, a chemical vapor deposition method or the like.

  Further, in Patent Document 1 (Japanese Patent No. 4138196), various source gases evaporated from an evaporation source are activated by high-density plasma generated by a pressure gradient arc discharge plasma gun, and a multi-component system is formed on a substrate in an oxygen atmosphere. An arc discharge reactive ion plating method for depositing a thin film made of an oxide ferroelectric has been proposed. In the arc discharge reaction type ion plating method, the evaporation amounts of various source gases evaporated from the evaporation source are detected using, for example, a crystal oscillator type film thickness sensor. Then, while monitoring the evaporation amount of various source gases detected by the film thickness sensor, the evaporation rate of the source gas evaporated from the evaporation source is controlled, and the thin film made of the multi-element oxide ferroelectric deposited on the substrate The composition ratio is controlled.

Japanese Patent No. 4138196

  An object of the present invention is to provide a multi-source deposition apparatus capable of controlling the composition ratio of a thin film composed of a plurality of elements deposited on a substrate more accurately than in the past.

  According to a main aspect of the present invention, when a plurality of types of vapor deposition materials are evaporated from a plurality of evaporation sources in a chamber to deposit a thin film composed of the plurality of types of vapor deposition materials on a substrate, A multi-source vapor deposition apparatus that controls the amount of evaporation of each of a plurality of types of vapor deposition materials while monitoring them with a plurality of film thickness sensors, wherein at least one of the plurality of film thickness sensors determines the film thickness of the vapor deposition material to be deposited A detection unit having a detection surface capable of being detected and disposed so that the detection surface faces an evaporation source of a deposition material to be detected; and an evaporation source of the deposition material to be detected by surrounding the detection surface And a barrier wall having a cylindrical shape extending toward the surface, and the barrier wall and an evaporation source of a vapor deposition material to be detected. When viewed from the evaporation source, the detection wall overlaps with the detection surface. The heat generating part has a shape overlapping with the barrier part. , Multi-source deposition system comprising, are provided.

  The composition ratio of the thin film composed of a plurality of elements deposited on the substrate can be controlled more accurately than in the past.

FIG. 1 is a side view showing a configuration of an arc discharge reaction type ion plating apparatus. 2A and 2B are a cross-sectional view showing the structure of the film thickness sensor and a plan view seen from the evaporation source of the vapor deposition material to be detected. FIG. 3A is a cross-sectional view showing a film thickness monitor when a PZT film is deposited, and FIG. 3B is a cross-sectional view of a film thickness sensor in which a heater is attached to the tip of the barrier. And FIG. 4A and 4B are a cross-sectional view showing the structure of the film thickness sensor according to the embodiment and a plan view seen from the evaporation source of the vapor deposition material to be detected. FIG. 5 is a table showing the relationship between the distance D between the barrier unit 32 and the heat generating unit 35 and the length T of the portion where the lump protrudes inside the barrier unit 32. and, 6A to 6D are a plan view and a cross-sectional view showing another example of the film thickness sensor according to the embodiment as seen from the evaporation source of the vapor deposition material to be detected.

FIG. 1 is a side view schematically showing a configuration of an arc discharge reactive ion plating apparatus which is an example of a multi-source deposition apparatus provided by the present inventor. This ion plating apparatus includes a substrate holder 20 disposed in the chamber 10, a plurality of evaporation sources 25 a to 25 c, a plurality of film thickness sensors 30 a to 30 c, and a reaction gas introduction pipe 50 connected to the chamber 10. And a plasma gun 60. The chamber 10 is connected to an evacuation apparatus, and the pressure in the chamber can be maintained at, for example, 1 × 10 ⁻⁴ Pa or less.

A substrate holder 20 is provided in the chamber 10 for holding a substrate 21 for depositing a thin film 22 made of, for example, a multi-element oxide ferroelectric. The substrate holder 20 is provided with a mechanism for heating and rotating the substrate 21. A plurality of evaporation sources 25 a to 25 c are arranged at positions facing the substrate 21. Each of the evaporation sources 25a to 25c is provided with an evaporation material constituting the thin film 22 to be evaporated on the substrate 21, and an electron beam gun for irradiating the evaporation material with an electron beam to heat and evaporate the evaporation material. For example, when depositing a thin film 22 made of _{PZT [Pb (Zr x Ti 1} -x) O 3] on the substrate 21, the deposition material of the evaporation source 25 a to 25 c, respectively Pb (lead), Zr (zirconium) Ti (titanium) is used. In addition, film thickness sensors 30 a to 30 c that can detect the evaporation amount of the vapor deposition material evaporated from the evaporation sources 25 a to 25 c are arranged around the substrate 21.

  An introduction pipe 50 for supplying a reaction gas is connected to the upper surface of the chamber 10 between the substrate 21 and the evaporation sources 25a to 25c. For example, when the thin film 22 made of PZT is deposited on the substrate 21, oxygen gas is introduced as a reaction gas from the introduction tube 50.

  Further, a plasma gun 60 including a discharge gas inlet, an anode, a cathode, a magnetic field generating coil and the like is connected to the side surface of the chamber 10. The plasma gun 60 ionizes and activates an inert gas (discharge gas) such as Ar (argon) or He (helium) by arc discharge. Then, the plasma 61 is led into the chamber 10 by the pressure gradient of the magnetic field / discharge gas generated by the magnetic field generating coil.

  The vapor deposition material evaporated from the evaporation sources 25 a to 25 c is activated when passing through the plasma 61 and reaches the substrate 21. For example, when oxygen gas is introduced as a reaction gas from the introduction pipe 50, the oxygen gas is activated by the plasma 61 and reacts with the vapor deposition material evaporated near the substrate 21 to form an oxide.

  The ion plating apparatus is further provided with a control device 70 for controlling the evaporation rate of the vapor deposition material evaporated from each of the evaporation sources 25a to 25c. The control device 70 monitors the evaporation amounts of various vapor deposition materials detected by the film thickness sensors 30a to 30c. Furthermore, based on the evaporation amount of the various vapor deposition materials, the electron beam gun provided in each of the evaporation sources 25a to 25c is controlled to control the evaporation rate of the various vapor deposition materials evaporated from each of the evaporation sources 25a to 25c. When the control device 70 performs such control, the thin film 22 can be deposited on the substrate 21 at a desired composition ratio.

  2A and 2B are a cross-sectional view showing the structure of the film thickness sensor and a plan view seen from the evaporation source of the vapor deposition material to be detected. The film thickness sensor 30 mainly includes a detection unit 31 and a barrier unit 32.

  The detection unit 31 has a detection surface 31s that can detect the film thickness of the deposited film 40 made of a vapor deposition material. And as shown to FIG. 2A, this detection surface 31s is arrange | positioned so that it may face the evaporation source of the vapor deposition material used as a detection target. The planar shape of the detection surface 31s of the detection unit 31 is circular as shown in FIG. 2B, for example.

  The detection surface 31 s of the detection unit 31 is configured by, for example, a crystal oscillator type film thickness sensor. When the deposited film 40 is deposited on the quartz vibrator type film thickness sensor, the resonance frequency of the quartz vibrator type film thickness sensor changes according to the mass of the deposited film 40. By detecting the resonance frequency of the crystal resonator type film thickness sensor, the film thickness of the deposited film 40 deposited on the crystal resonator type film thickness sensor or the evaporation amount of the vapor deposition material constituting the deposited film 40 is estimated. Is possible. Note that the detection surface 31s is not limited to a quartz vibrator type film thickness sensor, and may be configured by an interference fringe type film thickness sensor that uses interference of light applied to the deposited film 40.

  As shown in FIG. 2A, the barrier 32 extends toward the evaporation source of the evaporation material to be detected, and has a cylindrical shape surrounding the detection surface 31s of the detector 31 as shown in FIG. 2B. By having such a shape, as shown in FIG. 2A, vapor deposition materials other than the vapor deposition material to be detected can be made difficult to adhere to the detection surface 31s. Thereby, it becomes possible to detect the evaporation amount of the vapor deposition material to be detected more accurately. The barrier 32 can be made of, for example, stainless steel or alumina.

  The inventor deposited a thin film 22 made of PZT on the substrate 21 using the ion plating apparatus having such a configuration. A silicon substrate was used as the substrate 21, and Pb, Zr, and Ti were used as vapor deposition materials for the evaporation sources 25a to 25c, respectively. Further, the pressure in the chamber 10 was kept at 0.1 Pa, and oxygen gas was supplied from the introduction pipe 50 at a flow rate of about 200 sccm. Under such conditions, deposition was performed for about 60 minutes, and a PZT film 22 having a thickness of about 3 μm was deposited on the silicon substrate 21.

  FIG. 3A is a cross-sectional view showing a film thickness monitor when a PZT film is deposited. The film thickness sensor 30 used for vapor deposition has a diameter R1 of the detection surface 31s of about 12 mm, an inner diameter R2 of the barrier portion 32 of about 17 mm, a thickness W of the barrier portion 32 of about 1 mm, and a length L of the barrier portion 32 of about 50 mm. It is.

  When the PZT film 22 is deposited using such a film thickness sensor 30, a lump in which a powdery member is agglomerated at the tip of the barrier 32 of the film thickness sensor 30 that detects the amount of deposited Pb in particular. It was found that the body 33 adhered. This lump 33 is considered to be composed of oxidized Pb. The length T of the portion where the mass 33 protrudes inside the barrier 32 was about 0.8 mm. At this time, the effective inner diameter R3 of the barrier 32 is about 15.4 mm.

  When the PZT film 22 is deposited on the substrate 21, if such a mass 33 is attached to the tip of the barrier 32 of the film thickness sensor 30, the effective inner diameter of the barrier 32 is gradually reduced. . Thereby, the evaporation amount of the vapor deposition material may not be accurately detected by the film thickness sensor 30. If the evaporation amount of the vapor deposition material is not accurately detected, the evaporation rate of the vapor deposition material evaporated from the evaporation source is not accurately controlled. As a result, the PZT film 22 may not be deposited on the substrate 21 at a desired composition ratio. It is done.

  FIG. 3B is a cross-sectional view of a film thickness sensor in which a heater is attached to the tip of the barrier. Next, the inventor attached the heater 34 to the tip of the barrier 32 and deposited the PZT film 22 while heating the tip of the barrier 32. As a result, it has been found that the mass 33 does not adhere to the tip of the barrier 32. This is thought to be because the vapor deposition material (Pb) that is to adhere to the tip of the barrier 32 cannot be solidified because the tip of the barrier 32 is heated to a high temperature.

  However, it was found that when the film thickness sensor 30 having such a structure is used, the heat generated by the heater 34 propagates to the detection surface 31s, and the detection accuracy of the detection surface 31s decreases. If the detection accuracy of the detection surface 31s decreases, the evaporation amount of the vapor deposition material may still not be accurately detected. Thereby, the evaporation rate of the evaporation material evaporated from the evaporation source is not accurately controlled, and it is considered that the PZT film 22 is not evaporated on the substrate 21 at a desired composition ratio.

  The present inventor has examined the structure of the film thickness sensor so that the effective inner diameter of the barrier is not changed and the detection surface is not excessively heated when a thin film is deposited on the substrate.

  4A and 4B are a cross-sectional view showing the structure of the film thickness sensor according to the embodiment and a plan view seen from the evaporation source of the vapor deposition material to be detected. In addition to the detection unit 31 and the barrier unit 32, the film thickness sensor 30 further includes a heating unit 35 that is arranged at a distance D from the barrier unit 32, as shown in FIG. 4A. The heat generating portion 35 is configured to have an annular shape by winding a tungsten wire having a diameter R4 of about 0.5 mm once. The inner diameter of the annular heat generating part 35 is equal to the inner diameter R2 of the barrier part 32. As shown in FIG. 4B, the annular heat generating portion 35 is disposed so that the inner end thereof coincides with the inner end of the barrier portion 32. The heat generating unit 35 may be supported together with a support mechanism that supports the detection unit 31 and the barrier unit 32, or may be supported by an independent support mechanism that extends from the upper surface or side surface of the chamber 10 (see FIG. 1). It doesn't matter.

  When viewed from the evaporation source of the vapor deposition material to be detected, as shown in FIG. 4B, the tip of the barrier 32, particularly its inner part, overlaps the heat generating part 35 and becomes a shadow. Therefore, it is considered that no lump is attached to the tip of the barrier portion 32. Moreover, since the heat generating part 35 itself generates heat, the vapor deposition material cannot be solidified and the lump is not attached to the heat generating part 35. Therefore, it is considered that the effective inner diameter R2 of the barrier 32 is not changed when a thin film is deposited on the substrate. Furthermore, since the heat generating portion 35 is disposed away from the barrier portion 32, it is considered that the detection surface 31s is not excessively heated by the heat generated by the heat generating portion 35.

  The inventors have confirmed through experiments the relationship between the distance D between the barrier portion 32 and the heat generating portion 35 and the length T of the portion where the lump protrudes inside the barrier portion 32.

  FIG. 5 is a table showing the relationship between the distance D between the barrier unit 32 and the heat generating unit 35 and the length T of the portion where the lump protrudes inside the barrier unit 32. As described above, when the film thickness sensor 30 is not provided with the heat generating portion 35, the length T of the portion where the mass 33 protrudes inside the barrier 32 is about 0.8 mm.

  When the film thickness sensor 30 is provided with a heat generating portion 35 and the interval D between the barrier portion 32 and the heat generating portion 35 is about 1 mm or 5 mm, the length T of the portion where the mass 33 protrudes inside the barrier portion 32 is 0 mm. there were. That is, the part which the lump 33 protrudes inside the barrier part 32 did not arise. Further, when the distance D between the barrier 32 and the heat generating portion 35 is about 10 mm, the length T of the portion where the mass 33 protrudes inside the barrier 32 is about 0.2 mm.

  From the above experimental results, the film thickness sensor 30 provided with the heat generating portion 35 adheres the mass 33 to the tip of the barrier 32, particularly the inner portion thereof, compared to the film thickness sensor 30 not provided with the heat generating portion 35. It turned out that it can suppress. Furthermore, it has been found that by making the interval between the barrier 32 and the heat generating portion 35 narrower than 10 mm, the adhesion of the mass 33 to the inner portion of the tip of the barrier 32 can be further suppressed. In this experiment, the temperature of the heat generating part 35 is considered to be equal to or higher than the melting point of the mass 33 that is assumed to adhere to the barrier part 32. That is, it is considered that the temperature of the heat generating portion provided in the film thickness sensor for detecting the deposition amount of Pb was 890 ° C. or higher of the melting point of PbO (lead / oxygen) having the highest melting point among lead oxides.

  By using the film thickness sensor having such a structure, it becomes possible to detect the evaporation amount of the deposition material without changing the effective inner diameter of the barrier part and without excessively heating the detection surface. . As a result, the evaporation amount of the vapor deposition material to be detected can be monitored more accurately, and the evaporation rate of the vapor deposition material evaporated from the evaporation source can be controlled more accurately. As a result, it is considered that the composition ratio of the thin film composed of a plurality of elements deposited on the substrate can be controlled more accurately.

  6A to 6D are a plan view and a cross-sectional view showing another example of the film thickness sensor according to the embodiment as seen from the evaporation source of the vapor deposition material to be detected.

  In the film thickness sensor 30 according to the embodiment, the planar shape of the detection surface 31s is circular, but may be rectangular as shown in FIG. 6A. At this time, the barrier 32 may be formed in a cylindrical shape surrounding the detection surface 31s in accordance with the planar shape of the detection surface 31s. Further, when the heat generating portion 35 is viewed from the evaporation source of the vapor deposition material to be detected, the heat generating portion 35 does not overlap with the detection surface 31s and overlaps the barrier portion 32, particularly the inner portion thereof. Good. In the embodiment, the heat generating portion 35 is disposed so that the inner end thereof coincides with the inner end of the barrier portion 32. However, as shown in FIG. 6A, the heat generating portion 35 is at least the inner end 32a of the barrier portion 32 (see FIG. It may be arranged so as to overlap with the inner end 32a of the barrier 32 so as to hide (shown by a broken line in the figure).

  Further, in the film thickness sensor 30 according to the embodiment, a heater in which a tungsten wire is wound once around the heat generating portion 35 is used, but a heater in which a Kanthal wire or the like is wound a plurality of times may be used. Further, as shown in FIG. 6B, a plate-like heater made of carbon or the like and having an opening corresponding to the inner diameter R2 of the barrier portion 32 may be used.

  Further, as shown in FIG. 6C, the heat generating portion 35 may include a heated member 35a and a heater 35b that heats the heated member 35a. By using a member that can be easily molded as the heated member 35a, the degree of freedom in designing the shape of the heat generating portion 35 will be improved.

  Furthermore, in order to further reduce the propagation of the heat generated by the heat generating part 32 to the detection surface 31s, as shown in FIG. 6D, one or more heat shield plates 36 are provided between the barrier 32 and the heat generating part 35. May be arranged. The heat shield plate 36 has a shape corresponding to the heat generating part 35, and has an opening corresponding to the inner diameter R <b> 2 of the barrier part 32. Further, when viewed from the evaporation source of the vapor deposition material to be detected, it has a shape that does not overlap with the detection surface 31 s and overlaps with the barrier 32. For the heat shield plate 36, for example, stainless steel having low heat conductivity may be used.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not restrict | limited to these. For example, the structure of the film thickness sensor according to the embodiment can be applied to a film thickness sensor of a multi-source deposition apparatus using a so-called sputtering method. It will be apparent to those skilled in the art that other various modifications, improvements, combinations, and the like can be made.

10 chambers,
20 substrate holder,
21 substrate,
22 thin film,
25 evaporation sources,
30 film thickness center,
31 detector,
32 barrier,
33 lump,
34 heater,
35 exothermic part,
36 heat shield,
40 Deposition film,
50 reaction gas introduction pipe,
60 Plasma gun,
61 Plasma.

Claims (5)

In the chamber, when a plurality of types of vapor deposition materials are evaporated from a plurality of evaporation sources and a thin film composed of the plurality of types of vapor deposition materials is deposited on a substrate, the amount of evaporation of each of the plurality of types of vapor deposition materials is determined. , A multi-source deposition apparatus that controls while monitoring by a plurality of film thickness sensors,
At least one of the plurality of film thickness sensors is
A detection unit having a detection surface capable of detecting the film thickness of the deposited vapor deposition material, the detection surface being arranged to face the evaporation source of the vapor deposition material to be detected;
A barrier part having a cylindrical shape surrounding the detection surface and extending toward the evaporation source of the vapor deposition material to be detected;
A heating part disposed between the barrier part and the evaporation source of the vapor deposition material to be detected; and when viewed from the evaporation source, the heating part does not overlap the detection surface but has a shape overlapping the barrier part; , Including multi-source deposition equipment.   The multi-source vapor deposition apparatus according to claim 1, wherein the heat generating portion has a shape overlapping with an inner end of the barrier portion when viewed from an evaporation source of a vapor deposition material to be detected.   The multi-source deposition apparatus according to claim 1, wherein the heat generating unit includes a member to be heated and a heater for heating the member to be heated.   The multi-source deposition apparatus according to any one of claims 1 to 3, wherein an interval between the barrier portion and the heat generating portion is an interval narrower than 10 mm.   The multi-source deposition apparatus according to claim 1, further comprising a heat shield plate disposed between the barrier portion and the heat generating portion and having a shape corresponding to the heat generating portion.

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