JP2004052088A - Physical vapor deposition film deposition apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a physical vapor deposition film deposition apparatus having an optical transmission type film thickness gauge having resistance to disturbance to film thickness measurement and high degree of freedom in the film deposition apparatus. <P>SOLUTION: The physical vapor deposition film deposition apparatus has a vacuum chamber 100 and an optical transmission type film thickness gauge attached to the vacuum chamber 100. An optical window 10 for light incidence where the optical axis of the optical transmission type film thickness gauge is made incident from the outside of the vacuum chamber 100 on the inside, and an optical window 10 for routing which routes the the optical axis from the inside of the vacuum chamber 100 to the outside are formed on any one wall face among wall faces composing the vacuum chamber 100. Further, an optical path 14 introducing the propagation direction of the optical axis incident from the optical window 10 for incidence into the optical window 10 for routing so as to be turned over is fixed on the inside of the vacuum chamber 100 in the wall face. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a physical vapor deposition film forming apparatus, and in particular, is resistant to vibration and other disturbances caused by the rotation of a substrate rotation holder, the operation of a vacuum pump provided in a vacuum chamber, and other film thickness measurements, and the inside of the film forming apparatus. The present invention relates to a physical vapor deposition apparatus having an optical transmission type film thickness meter having a high degree of freedom.
[0002]
[Prior art]
A conventional example of an ion beam sputtering apparatus, which is a kind of physical vapor deposition apparatus, will be described with reference to FIG.
In FIG. 3, 1 is an ion source, 2 is a target, 3 is an ion beam, 4 is a sputtered particle, 7 is a substrate, 8 is a substrate rotating holder, 9 is a gas introduction tube, 10 is an optical window, 11 is an optical axis, and 12 Indicates a rotation measurement target. 100 is a vacuum chamber.
In the vacuum chamber 100, the ion source 1 is attached and accommodated on the side wall, and the target 2 is attached and accommodated on the bottom wall. The gas introduction pipe 9 is introduced and fixed to the side wall through the gas introduction pipe 9. The optical chamber 10 and a vacuum pump (not shown) are further attached to the vacuum chamber 100. The ion source 1 is attached and fixed to the inner surface of the side wall of the vacuum chamber 100, and an ion extraction grid to which a high voltage is applied is installed at the ion emission end. The target 2 is fixed to the bottom wall of the vacuum chamber 100 via a target holder (not shown). The substrate rotation holder 8 is rotatably supported by a rotation drive shaft 81 which is inserted through the upper wall of the vacuum chamber 100 in an airtight manner. This substrate substrate holder 8 is rotationally driven from the outside via a rotational drive shaft 81. Then, a film forming substrate 7 on which a thin film is to be formed is attached to the lower surface of the substrate rotating holder 8. The rotation plate 12 to be measured is attached to the upper wall via a rotation shaft 121.
[0003]
The vacuum chamber 100 is evacuated by a vacuum pump (not shown), and then an inert gas is introduced into the vacuum chamber 100 via the gas introduction pipe 9. Here, an ion beam 3 is generated from the ion source 1. The ion beam 3 generated from the ion source 1 is accelerated at high speed by an ion extraction grid to which a high voltage is applied, and is extracted and emitted as an ion beam. This beam collides with the target 2 and sputters the material constituting the target 2. As the material of the target 2, various kinds of materials such as a metal material, an insulating material, and the like can be used. The sputtered particles 4 of the target constituent material sputtered from the target 2 adhere to the surface of the substrate 7 on which the thin film held by the substrate rotating holder 8 is to be formed, and the thin film of the target constituent material is formed here. become. The sputtered sputtered particles 4 of the target constituent material are simultaneously formed on the surface of the rotating plate 12 to be measured which is positioned and fixed in the vicinity of the substrate rotating holder 8. When this thin film is being formed, the substrate rotation holder 8 is rotated by the rotation shaft 81, so that the thickness of the thin film formed can be made uniform.
[0004]
Incidentally, a film thickness gauge is attached to the ion beam sputtering apparatus, and a thin film is formed while measuring the film thickness with the film thickness meter. Although a quartz crystal type can be used as the film thickness meter, an optical film thickness meter is generally provided to measure the film thickness in order to perform a highly accurate film thickness measurement. . This optical film thickness meter irradiates light having a specific wavelength along an optical axis 11 onto a thin film formed on the surface of a rotating plate 12 to be measured through an optical window 10, and transmits the light having a specific wavelength. The film thickness is monitored by measuring the change in reflectance or reflectance.
[0005]
In particular, in a conventional example of an ion beam sputtering apparatus provided with an optical transmission type film thickness meter based on transmittance measurement, the optical path of the optical transmission type film thickness meter is usually used to simplify the configuration, and In order to prevent the sputtered particles 4 flying from the target 2 from being blocked by the optical path, as shown in the figure, an optical window 10 is provided on the wall of a vacuum chamber 100 on which a substrate rotating holder 8 on which a substrate 7 to be formed is mounted is mounted. , And is configured to introduce light through the wall. That is, no optical element other than the rotation plate 12 to be measured is arranged in the optical path of the optical axis 11 introduced through the optical window 10, and the light is directly incident on the rotation plate 12 to be measured.
[0006]
[Problems to be solved by the invention]
In the above-described conventional example, the optical transmission type film thickness meter measures the vibration of the motor for driving the substrate rotation holder 8 attached to the upper wall of the vacuum chamber 100, the vibration caused by the operation of the vacuum pump, and these vibrations. It is affected by the distortion of the vacuum chamber 100 itself. That is, the optical window 10 made of glass or another transparent material vibrates irrespective of the transmittance of the film-forming sample formed on the rotating plate 12 to be measured due to the previous vibration, and is outside the vacuum chamber 100. This affects the coupling efficiency of the optical axis 11 from the light source to the light detection unit itself, and becomes noise superimposed on the photoelectric conversion signal in measuring the film thickness of the film-formed sample.
[0007]
In the conventional example shown in FIG. 3, the optical window 10 is fixed to the bottom wall of the vacuum chamber 100 on the light incident side, and the rotating plate 12 to be measured is fixed to the upper wall opposite to the bottom wall. Therefore, the optical window 10 and the rotating plate 12 to be measured are exposed to different vibrations of the upper wall and the bottom wall having different phases. From this, the rotation plate 12 to be measured vibrates relatively with respect to the optical axis 11 of the incident light. Since the transmittance and other optical properties of the film generally depend on the incident angle of light, in this case, in particular, a change in the angle between the thin film surface of the rotating plate 12 to be measured and the optical axis 11 causes further disturbance in the film thickness measurement. Become.
[0008]
In the formation of an optical multi-layer film of several hundred layers, when the film thickness is measured using the optical transmission type film thickness meter in which the above-described disturbance occurs, measurement errors of each film thickness measurement are accumulated and the final measurement is performed. Optically, an optical multilayer product containing a large error is produced. High precision optical performance cannot be guaranteed for this product. As an example, when manufacturing a narrow-band multilayer optical filter, a thin film is formed with sufficient accuracy to meet the accuracy requirement that the relative thickness error of each required thin film be suppressed to 0.01% or less. It is extremely difficult to do.
[0009]
Here, in the conventional example, since the optical window 10 and the rotating plate 12 to be measured are separately attached and fixed to the respective upper and bottom walls and vibrate independently of each other, the entirety of the vacuum chamber 100 is Even if an attempt is made to increase the rigidity to suppress the distortion due to the above-mentioned vibration, this has almost no effect. In the case where the optical axis 11 is made to directly enter the rotation plate 12 to be measured via the optical window 10, there is no sputtering device in the optical path between the optical window 10 and the rotation plate 12 to be measured. Therefore, the design and mounting position of the rotating plate 12 to be measured on which the film-forming sample is formed cannot be freely set.
[0010]
The present invention relates to an ion beam sputtering apparatus and other film forming apparatuses, which are resistant to vibration and other disturbances caused by the operation of a vacuum pump provided in a vacuum chamber due to rotation of a substrate rotation holder and other film thickness measurements. It is intended to provide a physical vapor deposition apparatus capable of designing an optical film thickness measuring apparatus having a high degree of freedom within the apparatus.
[0011]
[Means for Solving the Problems]
Claim 1: In a physical vapor deposition apparatus having a vacuum chamber 100 and an optical transmission type film thickness meter attached to the vacuum chamber 100, any one of the wall surfaces constituting the vacuum chamber 100 An optical window 10 for inputting the optical axis of the optical transmission type film thickness meter from the outside to the inside of the vacuum chamber 100 and an optical window 10 for leading out from the inside of the vacuum chamber 100 to the outside; Inside the vacuum chamber 100 on the wall surface, a physical vapor deposition apparatus in which an optical path 14 for turning the propagation direction of the optical axis incident from the optical window 10 for incidence and leading to the optical window 10 for derivation is attached and fixed is configured. did.
[0012]
Claim 2: In the physical vapor deposition apparatus according to claim 1, a thin film is further formed inside the vacuum chamber on the wall surface of the vacuum chamber to which the two optical windows 10 and the optical path 14 are attached and fixed. A physical vapor deposition apparatus was constructed in which a substrate rotating holder 8 holding a substrate 7 to be formed was connected via a rotation drive shaft 81.
Claim 3: In the physical vapor deposition film forming apparatus according to any one of Claims 1 and 2, the signal light and the incident portion 131 for making the optical axis enter through the optical window 10 for incidence. An incident light receiving unit 13 including a light receiving unit 132 that receives light through an optical window 10 for deriving and photoelectrically converts the light, and a light source 15 that generates light serving as an element of an optical axis. A physical vapor deposition apparatus having a transmitted light detection controller 16 for receiving a signal was configured.
[0013]
Further, in the physical vapor deposition apparatus according to any one of claims 4, 1 to 3, a measurement target plate 12 'on which a measurement target thin film is formed is attached to the substrate rotating holder 8. A fixed physical vapor deposition apparatus was constructed.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the embodiment of FIG. In the embodiments, members common to members in the conventional example are denoted by common reference numerals.
The substrate rotation holder 8 is attached to the upper wall of the vacuum chamber 100 via a rotation shaft 81, and is rotationally driven by a driving motor coupled to the rotation shaft 81.
The rotating plate 12 to be measured adopts a rotating configuration so that the whole of the sputtered particles 4 is less likely to be blocked by a member such as the optical path 14 constituting the ion beam sputtering apparatus. The optical path 11 that bends the optical axis 11 in a free direction or changes the optical properties of the optical axis 11 using a passive optical element such as the optical path 14 or an active optical element such as a modulator (not shown) is used. Make up. Using this optical path 14, a thin film sample formed by sputter particles formed on the rotating plate 12 to be measured is measured.
[0015]
The optical path 14 includes a plurality of mirrors including a first mirror 141 and a second mirror 142 and an arm 140 connecting the mirrors, and bends the optical axis 11 into a desired U-shape. The optical path 14 is attached and fixed to the upper wall of the vacuum chamber 100. In the embodiment shown in FIG. 1, the optical axis 11 of the measurement is incident on the vacuum chamber 100 via the optical window 10 and then the thin film formed on the rotary plate 12 to be measured via the optical path 14 is measured. After being transmitted, it is taken out through the optical window 10. The optical axis 11 also adopts a configuration in which after entering the vacuum chamber 100, the optical axis 11 first passes through a thin film formed on the rotating plate 12 to be measured, and then is taken out of the vacuum chamber 100 via the optical path 14. Can be. The two optical windows 10 are also fixed to the upper wall to which the optical path 14 is fixed. Since the optical path 14 is a member that can be configured to be compact in nature, its rigidity can be easily increased according to the required degree of vibration resistance.
[0016]
As described above, the optical path 14 including the two optical windows 10, the plurality of mirrors including the first mirror 141 and the second mirror 142, and the arm 140 connecting them, and the thin film should be formed. The three substrate rotation holders 8 that hold the substrate 7 and are rotationally driven by a motor via a rotation shaft 81 are attached to the upper wall of a common vacuum chamber 100.
Another embodiment will be described with reference to FIG. In the embodiment of FIG. 2, members common to those in the embodiment of FIG. 1 are given the same reference numerals.
[0017]
In the embodiment, a pump used for evacuation of the vacuum chamber 100 is a second vacuum pump 62 composed of a rotary pump capable of sucking from atmospheric pressure to a certain degree of vacuum, and an ultrahigh vacuum state. A first vacuum pump 61 composed of a cryopump is provided. Actually, the cryopump constituting the first vacuum pump 61 cannot be used until the degree of vacuum is increased to a certain degree. A two-stage evacuation is performed after use. The vacuum chamber 100 corresponding to the housing of the ion beam sputtering apparatus is a stainless steel container having a front door 101 and a back door 102 and having a thickness of about 30 mm and a volume of about 1000 mm ^3. By using the pump 61 and the second vacuum pump 62, the inside of the container can be brought into an ultra-high vacuum state. Since this cryopump is a kind of refrigerator, vibration is generated from the compressor, and this gives vibration to the vacuum chamber 5. The sputtered particles 4 are generated when the ion beam 3 emitted from the ion source 1 collides with the target 2. At this time, a necessary gas is additionally introduced through a gas introduction pipe 9.
[0018]
The embodiment of FIG. 2 is different from the embodiment of FIG. 1 in that the measurement target plate 12 ′ on which the measurement target thin film is formed is also fixedly held on the substrate rotating holder 8 together with the substrate 7 on which the thin film is to be formed. The two plates are rotated by the motor 5 during the operation of the sputtering apparatus. In this case, the measurement target plate 12 'on which the thin film sample is to be formed and the substrate 7 on which the thin film is to be formed are similarly configured without distinction, and an appropriate one selected is treated as the measurement target plate 12'. .
A substrate rotating holder 8 for holding a substrate 7 on which a thin film is to be formed is attached to a front door 101 of a vacuum chamber 100 via a rotating shaft 81 and is driven to rotate by a motor 5, which also causes vibration. This vibration also gives vibration to the front door 101 of the vacuum chamber 100.
[0019]
The incident light receiving section 13 is attached and fixed to the front door 101 of the vacuum chamber 100 via a surface plate (not shown). Light sent to the optical fiber 130 from the light source 15 that generates light serving as the element of the optical axis exits through the lens of the incident part 131 of the incident light receiving part 13, and the optical axis 11 is formed. On the front door 101 of the vacuum chamber 100, an optical path 14 including a plurality of mirrors including a first mirror 141 and a second mirror 142 and an arm 140 connecting these mirrors, and an optical window 10 are also fixed. Have been. In this embodiment, as in the previous embodiment, the two optical windows 10, the optical path 14, and the substrate rotating holder 8 are all commonly mounted on the front door 101 of the vacuum chamber 100. .
[0020]
The optical axis 11 that is incident and formed through the lens of the incident part 131 of the incident light receiving part 13 reflects the first mirror 141 and the second mirror 142 to move the measurement target plate 12 ′ on which the thin film sample is formed. The light passes through the other optical window 10, passes through the lens of the light receiving unit 132 of the incident light receiving unit 13, is condensed on a photodiode constituting the light receiving unit 132, and is photoelectrically converted. This converted electric signal is coaxial. The transmitted light is transmitted to the transmitted light detection controller 16 via the cable 133. The transmitted light detection controller 16 receives an electric signal obtained by photoelectrically converting the light transmitted through the measurement target plate 12 ′ on which the thin film sample is formed, and uses the electric signal for controlling the operation of the ion beam sputtering apparatus. In this embodiment, the optical transmission type film thickness meter includes a light source 15, an incident light receiving unit 13, an optical window 10, an optical path 14, and a transmitted light detection control unit 16.
[0021]
According to the invention described above, the optical window 10 vibrates regardless of the transmittance of the film-forming sample formed on the rotating plate 12 to be measured due to the vibration of the vacuum chamber 100, and Influence on the coupling efficiency itself of the optical axis 11 and the adverse effect on the photoelectric conversion signal in measuring the film thickness of the film-formed sample is caused by the fact that the transmission part of the optical axis 11 in the configuration of the optical transmission type film thickness meter is substantially in phase. Therefore, it is possible to suppress the vibration by using a configuration that vibrates with the same frequency component.
In the configuration of the optical transmission type film thickness meter, the optical axis 11 transmitting portion is vibrated at substantially the same phase and with the same frequency component. The structure is such that the user is commonly attached to the front door 101 of the vacuum chamber 100, and these are concentrated on the front door 101, which is a common wall, so that the rigidity of those components can be intensively improved as necessary. Can be easily designed, and distortion of the optical portion of the optical transmission type thickness gauge induced by vibration or other external force can be easily reduced. In addition, since the degree of freedom of the configuration of the optical portion is increased, when it is desired to change the film thickness measurement point, the shape can be easily changed without changing the film forming apparatus by changing the shape of the optical path 14 and replacing it. can do.
[0022]
Further, a part of the sputtered particles 4 flying to the substrate rotating holder 8 is shielded by the optical path 14. The effect of this shielding is caused by a film thickness compensating plate for adjusting the distribution of the sputtered particles 4 flying to the substrate rotating holder 8. Can be easily eliminated by adding the design.
Here, the measurement target plate 12 'is fixedly held on the substrate rotating holder 8 together with the substrate 7 on which the thin film is to be formed, and the measurement target plate 12' and the substrate 7 on which the thin film is to be formed are similarly distinguished. By configuring and handling the selected one as the measurement target plate 12 ', the thin film to be formed on the substrate 7 itself is to be measured, which leads to improvement in measurement accuracy.
[0023]
According to the above-described embodiment, for example, when manufacturing a narrow band optical filter, it is necessary to control a required thickness of a thin film to control a relative thickness error of each thickness to 0.01% or less. Thus, the yield in forming a thin film can be improved.
In the above, an ion beam sputtering apparatus has been described as an example, but the present invention can be applied to a film forming apparatus by physical vapor deposition other than the ion beam sputtering apparatus.
[0024]
【The invention's effect】
As described above, according to the present invention, the rotation of the substrate rotation holder, the disturbance to vibration and other film thickness measurement caused by the operation of the vacuum pump provided in the vacuum chamber, and, in the film forming apparatus A physical vapor deposition apparatus having an optical transmission type film thickness meter having a high degree of freedom can be provided.
[Brief description of the drawings]
FIG. 1 illustrates an embodiment.
FIG. 2 is a diagram illustrating another embodiment.
FIG. 3 illustrates a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ion source 2 Target 3 Ion beam 4 Sputtered particle 5 Motor 6 Vacuum pump 61 1st vacuum pump 62 2nd vacuum pump 7 Substrate 8 Substrate rotation holder 81 Rotation drive shaft 9 Gas introduction pipe 10 Optical window 11 Optical axis 12 Measurement Target rotating plate 12 ′ Measurement target plate 121 Rotation axis 13 Incident light receiving unit 130 Optical fiber 131 Incident unit 132 Light receiving unit 133 Coaxial cable 14 Optical path 140 Arm 141 First mirror 142 Second mirror 15 Light source 16 Transmitted light detection control unit 100 vacuum chamber 101 front door 102 back door

Claims (4)

In a physical vapor deposition apparatus having a vacuum chamber and an optical transmission type film thickness meter attached to the vacuum chamber,
On one of the walls constituting the vacuum chamber, the optical axis of the optical transmission type thickness gauge is guided from the outside of the vacuum chamber to the inside, and the optical axis for incidence is introduced from the inside of the vacuum chamber to the outside. In addition to forming an optical window for output, an optical path for turning the propagation direction of the optical axis incident from the optical window for incidence and leading to the optical window for output is attached and fixed inside the vacuum chamber on the wall. A physical vapor deposition apparatus. The physical vapor deposition apparatus according to claim 1,
A substrate rotation holder for holding a substrate on which a thin film is to be further formed is connected to a wall of the vacuum chamber to which two optical windows and an optical path are attached and fixed via a rotation drive shaft. Physical vapor deposition film forming apparatus. A physical vapor deposition apparatus according to any one of claims 1 and 2,
Includes an incident light receiving unit consisting of a light receiving unit that makes the optical axis incident through an optical window for incidence and a light receiving unit that photoelectrically converts and receives signal light through an optical window for derivation,
A light source that generates light that is the element of the optical axis,
A physical vapor deposition apparatus comprising a transmitted light detection control unit that receives a photoelectrically converted electric signal. A physical vapor deposition apparatus according to any one of claims 1 to 3,
A physical vapor deposition apparatus wherein a measurement target plate on which a measurement target thin film is formed is fixedly held on a substrate rotating holder.

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