JPH06458Y2 - Temperature measuring device for thermal plasma torch - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a thermal plasma torch for vapor-depositing a crystalline film such as synthetic diamond on a movable substrate surface.
It relates to a device for measuring a substrate temperature.

[Conventional technology]

The diamond film artificially synthesized by the vapor phase method is
Utilizing its excellent properties, it is being applied to a wide range of fields such as precision processing, electronics, optics, and medicine.

Up to now, a high-frequency thermal plasma method, a direct-current plasma method, a microwave plasma method, an arc plasma method, a plasma jet method, etc. have been known as methods for synthesizing diamond by a vapor phase method, but these methods are all divided. In addition, a mechanism is adopted in which a crystal film is formed by injecting plasma containing carbon atoms and carbon radicals onto the surface of a base placed on a base holder in a thermal plasma torch.

In this type of vapor phase deposition, the temperature of the gas has a significant effect on the properties of the deposited film. Therefore, the measurement of the gas temperature is extremely useful for elucidating the reaction mechanism, adjusting the film structure, controlling the deposition rate, etc. It becomes effective. However, since the thermal plasma is accompanied by a high temperature of several thousand degrees and strong light emission, it is impossible to measure the temperature with a usual thermocouple or optical pyrometer.

In view of such circumstances, as a device that can easily measure the temperature of the substrate during the reaction, a holder for mounting the substrate is a thermal plasma composed of a water-cooled jacket with a thermometric sensor inserted in the central through hole. A temperature measuring holder for a torch has been developed and provided by the present applicant. (Actual application Sho 63-12
No. 5377).

[Problems to be solved by the device]

In vapor phase deposition, in order to increase the production area of the crystal film and obtain a uniform film, the substrate temperature should be in the optimum range (700
It is effective to maintain a temperature of up to 1000 ° C.) and to move the substrate to continuously move the surface hit by the plasma. However, the temperature measuring holder of Japanese Utility Model Application No. 63-125377 cannot structurally detect the temperature of the movable portion of the substrate.

An object of the present invention is to provide a temperature measuring device for a thermal plasma torch having a mechanism capable of accurately measuring the temperature of a substrate which is continuously rotated horizontally or repeatedly rotated horizontally and horizontally.

[Means for Solving the Problems]

The temperature measuring device for a thermal plasma torch according to the present invention for achieving the above object has a plurality of through holes or slits formed in a concentric surface of a movable base holder that rotates and / or moves horizontally. Alternatively, the constructional feature is that a temperature measuring sensor inserted in a water cooling jacket is closely fixed to the lower surface through which the slit passes.

The temperature detecting sensor that constitutes this invention is an alumina single crystal or quartz single crystal that has a high light transmittance in the detection wavelength range (for example, 0.4 to 1.2 μm) at the tip of a water-cooled jacket and does not deteriorate (devitrify) at high temperatures. Those having a structure in which a ceramics-based optical sensor such as is attached are preferably used.

[Action]

According to the temperature measuring device for the thermal plasma torch having the above-described configuration, the light emitted through the through hole or slit provided in the movable substrate holder that horizontally rotates and / or moves horizontally is detected by the temperature detecting sensor installed on the lower surface. Then, it is transmitted as a signal of the substrate temperature to a measuring device outside the system.

The temperature measuring mechanism may be a method in which the temperature is measured when the through hole or slit overlaps with the temperature sensor position in synchronization with the rotation speed of the substrate, or the temperature is constantly monitored without synchronization and the temperature is measured above a certain value. A method of calculating the substrate temperature by detecting when it is warm can be adopted, but in any case, it is possible to measure the base end temperature with high accuracy.

〔Example〕

 The present invention will be described below based on the illustrated embodiment.

Example 1 FIG. 1 is a cross-sectional view showing an example in which one aspect of the present invention is applied to high frequency plasma, and 1 is a reaction gas supplier 2 and a valve 3 (for hydrocarbon gas), 4 (for hydrogen gas). And a nozzle cylinder connected through 5 (for argon gas), 6 is a plasma generating chamber equipped with a work coil 8 for connecting a high frequency power source 7 to the peripheral portion, and 9 is connected to the lower portion of the plasma generating chamber 6. A wide diameter production chamber, and 10 is an exhaust system.

Inside the generation chamber 9, there is provided a mechanism in which the supporting column portion is horizontally rotated via an appropriate driving means 12 outside the system at a position setting such that when the substrate 11 rotates, its half surface portion continuously hits the plasma flow. The movable substrate holder 13 is attached. The movable substrate holder 13 has a water cooling jacket structure in which cooling water flows back, and a plurality of through holes 14 are formed in a concentric surface on which the center of the plasma frame abuts.
Has been drilled. Then, the movable substrate holder 13
A temperature sensor 15 is fixed in proximity to the lower surface through which the through hole 14 passes when rotating. The temperature sensor 15 has a structure in which a ceramics optical sensor 17 such as an alumina single crystal or a quartz single crystal is attached to the tip of a tubular body of a water cooling jacket 16 and connected to a measuring instrument 19 outside the system by an optical fiber 18. Prepare

FIG. 2 is an enlarged view of the substrate holder portion in FIG. 1, where (A) is a vertical sectional view and (A) is a bottom view. Eight through-holes 14 are concentrically formed in the base body holder 13 at equal intervals, and a temperature sensor 15 is installed close to the lower surface of the track through which the through-holes 14 pass when the base body rotates.

The temperature measuring device for the thermal plasma torch configured as described above is incorporated into the high frequency plasma generation chamber, and the pressure is 1 atm,
Power supply frequency: 4 MHz, vacuum tube input: 55 KVA, CH ₄ (0.4 / min), Ar (40 / min), H _{2 in the system}
High-frequency plasma was generated while a reaction gas composed of (6 / min) was introduced and the movable substrate holder was horizontally rotated at 1 revolution / minute to form a diamond film on the substrate surface.

The base is made of molybdenum, and the temperature sensor is equipped with an optical sensor (alumina single crystal, diameter 1.27 mm) of the Accufiber temperature measurement system model 100 (manufactured by Accufiber Inc., USA) at the tip of the water cooling jacket. The set one was used.

When the temperature of the substrate was measured in this state, it was stable in the range of 780 to 840 ° C., and a homogeneous and high quality diamond film of 20 μm was formed by the reaction for 8 hours.

Embodiment 2 FIG. 3 is a partially enlarged view showing an embodiment in which the movable base holder is horizontally rotated and simultaneously moved horizontally.
(A) is a longitudinal sectional view and (A) is a bottom view.

In this example, eight slits 20 are formed in the concentric circular surface of the movable substrate holder 13 having a water-cooled jacket structure in a radial pattern at equal intervals, and the slits 20 pass through when the movable substrate holder 13 rotates laterally. Temperature sensor 1
5 is fixed in close proximity. In this case, the slit 20
The length of is set within the range of horizontal movement.

The same as Example 1 except that the temperature measuring device for the thermal plasma torch having this structure was set in the high frequency plasma chamber, and the movable substrate holder had a mechanism of repeating horizontal rotation at 1 rotation / minute and horizontal movement at 10 cm / 5 minutes. A diamond film was formed under the conditions.

It was confirmed that the substrate temperature during the reaction was stable in the range of 770 to 830 ° C., and a uniform and high-quality diamond film of about 20 μm was formed in 8 hours.

[Effect of device]

As described above, according to the temperature measuring device for the thermal plasma torch of the present invention, it is possible to easily and accurately measure the temperature of the movable base body that rotates or / and moves horizontally. Therefore, elucidation of reaction mechanism, adjustment of formed membrane structure,
It can be used for controlling the deposition rate, etc., and normal vapor phase growth is always possible regardless of the type of the substrate material.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which one embodiment of the temperature measuring device for a thermal plasma torch according to the present invention is applied to high-frequency plasma, and FIG. 2 is an enlarged view of the movable substrate holder part of FIG. ) Is a longitudinal sectional view, and (a) is a bottom view.
FIG. 3 is an enlarged view of a movable base holder portion of another embodiment, in which (A) is a vertical sectional view and (A) is a bottom view. DESCRIPTION OF SYMBOLS 1 ... Nozzle cylinder 2 ... Reactive gas supply device 3, 4, 5 ... Valve 6 ... Plasma generation chamber 7 ... High frequency power supply 8 ... Work coil 9 ... Generation chamber 10 ... Exhaust device 11 ... Substrate 12 ... Driving means 13 ... Movable substrate holder 14 ... Through hole 15 ... Temperature sensor 16 ... Water cooling jacket 17 ... Optical sensor 18 ... Optical fiber 19 ... Measuring instrument 20 ... Slit

Claims (1)

[Scope of utility model registration request] 1. A lower surface through which a plurality of through holes (14) or slits (20) are bored in a concentric surface of a movable base body holder (13) which rotates and / or moves horizontally, and through which the through holes or slits pass. A temperature measuring device for a thermal plasma torch, in which a temperature sensor (15) inserted into a water cooling jacket (16) is fixed in proximity.