JPS62280361A - Sensor for monitoring vacuum deposition - Google Patents

Abstract

PURPOSE:To sensitively detect an evaporated material by constituting the titled sensor so that electron impact beams radiated by subjecting the evaporated material to electron impact are converged by a reflecting mirror in a range over a broad angle and taken out to the outside. CONSTITUTION:Thermions radiated by heating a filament 25 are accelerated by convergent electrodes 28, 29 and focused and run toward an anode electrode 27 in order to subject vapor taken-in through a flow path 20 for vapor to electron impact. The vapor subjected to electron impact emits electron impact beams peculiar in an evaporated material when it is returned to a metastable state. The electron impact beams are focused by a reflecting mirror 30 and passed through a hole 22 and changed into an electrical signal by a photomultiplier via an optical filter provided to the outside. Evaporation velocity is measured by measuring the strength of the signal changed into electrical signal.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Industrial Application Field] The present invention focuses electron bombarded light generated by evaporated matter excited by electron bombardment using a reflecting mirror. The present invention relates to a vacuum deposition monitoring sensor configured to detect.

[Conventional technology]

For example, as shown in Fig. 4 (US Patent Publication No. 4,036.167). ErES (Electron
Tmpa-ct 0m1ssion 5pectro
scopy) sensor 10 has a rectangular parallelepiped-shaped cane, consisting of a bottom plate 12, a corresponding top plate (removed to show the interior), and two opposing side plates 14, 15 (15).
(most of which has been removed to reveal the interior). On the bottom plate l2 and the top plate,
A vapor flow path 20 is provided for passing a portion of the vapor to be monitored.

A hole 22 is provided in the side plate 15 to provide an optical path perpendicular to the steam flow passing through the steam channel 20 .

The excitation electron beam is generated by heating the filament 25 shown at the right end of FIG. It is accelerated to produce lower energy electrons. Anode electrode 2
7 is disposed on the end plate 16 on the opposite side of the steam flow path 20, and is configured so that the excitation electrons generated by the filament 25 travel across the steam flow. Positively charged focusing electrodes 28,29 are placed in the electron beam path to form an excitation beam with limited tongue energy and limited shape.

The steam flow passing through the steam flow path 20 passes through the filament 25,
The vapor is excited by the excitation electrons generated and accelerated using the focusing electrode 29 and the focusing electrode 28, and when the excited substance returns to a metastable state, the light emitted from the vapor is emitted from the hole. 22 and taken out to the outside. This extracted light is passed through an optical filter or monochromator.
After that, it is converted into an electrical signal by a photodetector such as Photomar, which is used to monitor and control the deposition rate.

[Problem that the invention seeks to solve]

A conventional vacuum evaporation monitoring sensor configured as shown in FIG. Since a configuration was adopted in which an impact light is generated, the generated electron impact light is taken out to the outside through a hole 22 provided in the side plate 15, and converted into an electrical signal via an optical filter/photomultiplier, the evaporated matter is not affected by the electron impact. Of the electron impact light generated, only that within the angle range that looks into the hole 22 can be extracted to the outside and converted into an electrical signal.
When such elements as evaporated, the detection sensitivity becomes insufficient, causing problems in monitoring and controlling the evaporation rate.

(Objective of the Invention) The present invention improves detection sensitivity by adopting a configuration in which electron impact light emitted by electron impacting T activation is taken out in a manner that converges it over a wide angular range using a reflecting mirror. The purpose is to provide a sensor for monitoring high vacuum deposition.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides an electron number (for example, a filament 25, a focusing electrode 28, 29, and an anode electrode 27) that generate accelerated electrons as shown in FIG.
and a reflecting mirror (for example, a flat reflecting mirror 30) disposed near the path where the evaporated matter is irradiated by accelerated electrons, and the electron impact light emitted in the front direction is reflected in the front direction using the reflecting mirror. The system detects the focused electron impact light.

[Effect]

Adopting the configuration explained using FIG. 1, the filament 2
When the filament 5 is heated, thermionic electrons emitted from the filament 25 are accelerated and focused by the focusing electrode 29.2 and travel toward the anode electrode 27 to electron bombard the vapor taken in from the vapor flow path 20. do. The electron bombarded vapor becomes excited. When this excited vapor returns to a metastable state, it emits electron impact light that is characteristic of evaporated substances.

- Of this radially emitted electron impact light, the part emitted to the front is taken out to the outside through the hole 22, while the part emitted to the back is reflected to the front by a reflecting mirror (for example, the flat reflecting mirror 30). It is reflected in the direction and taken out through the hole 22 to the outside.

This electron impact light taken out to the outside is converted into an electrical signal by a photomultiplier through an optical filter. By measuring the intensity of the signal converted into an electrical signal, it becomes possible to measure the evaporation rate.

As mentioned above, among the electron impact light emitted radially,
By adopting a configuration in which the radiation emitted to the front is directly taken out to the outside through the hole 22, while the radiation emitted to the back is reflected to the front using a reflector and taken out through the hole 22, It becomes possible to improve the detection sensitivity by increasing the collection efficiency of electron impact light.

〔Example〕

Next, the configuration and operation of one embodiment of the present invention will be explained in detail using FIG. FIG. 1(a) shows a plan cross-sectional view of the structure of one embodiment of the present invention, and FIG. 1(b) shows a front view of the structure of one embodiment of the present invention.

In FIG. 1(a), filament 25, focusing electrode 2
9.28 and the anode electrode 27 constitute an electron source. The filament 25 is, for example, a tungsten wire formed into a spiral shape as shown in the figure, and thermoelectrons are emitted by heating the filament 25 with electricity. The emitted thermoelectrons are focused and accelerated by focusing electrodes 28 and 29 that are at a positive potential with respect to the filament 25, and travel toward the anode electrode 27. The electrons are disposed so that they are interlinked with the steam flow taken in from the steam flow path 20 shown in the drawing.

The plane reflecting mirror 30 reflects electron impact light emitted in the back direction toward the front, among the electron impact light generated by electron irradiation of the steam taken in from the steam flow path 20 with accelerated electrons. This is arranged in an axially symmetrical position with respect to the hole 22 for extracting the electron impact light to the outside.

The sensor 10 has a rectangular parallelepiped shape with side plates 14.15, end plates 16.17, bottom plate 12 and a top plate (not shown). A rectangular steam passage 20 is opened in this bottom plate 12 as shown in the figure. Similarly, a rectangular steam passage is opened in the top plate at a position corresponding to the bottom plate 12.

The side plate 15 is provided with a circular hole 22, as shown in FIG. The electron impact light is extracted to the outside.

Next, the operation will be explained in detail.

In FIG. 1, when the filament 25 is heated with electricity,
Thermionic electrons are emitted. The emitted thermoelectrons are accelerated and focused by the focusing electrodes 29 and 28, and while electron bombarding the vapor taken in from the vapor flow path 20, the anode electrode 29.
run towards.

The electron bombarded vapor becomes excited. Of the electron impact light unique to the substance that is emitted radially when the excited vapor returns to a metastable state, firstly, the electron impact light emitted to the front is caused by the hole provided in the side plate 15 as shown by the arrow a in the figure. 22 to the outside. Second, the radiation emitted to the back surface as shown by the arrow C in the figure is reflected by the plane reflecting mirror 30 and taken out to the outside through the hole 22 provided in the side plate 15 as shown by the arrow C in the figure. These first and second electron impact lights taken out to the outside are subjected to photoelectric conversion by a photomultiplier through an optical filter.

FIG. 2 shows a configuration diagram of another embodiment of the present invention, in which a concave reflector 31 is used in place of the plane reflector 30 used in the configuration shown in FIG. By using this concave reflecting mirror 31, the electron impact light emitted in the back direction as shown by the arrow d in FIG. It is reflected in the direction and can be taken out through the hole 22.

Therefore, it is possible to further improve the electron impact light collection efficiency compared to the configuration shown in FIG.

According to experiments, when using the flat reflecting mirror ff130 shown in FIG.
Furthermore, when the concave reflecting mirror 31 shown in FIG. 2 is used,
About twice the electron impact light collection efficiency was obtained.

Next, the operation of the system for controlling the evaporation rate will be briefly explained using FIG.

In FIG. 3, inside the vacuum chamber 40, E[ES
The sensor lO and the crystal sensor 41 evaporate alii4
They are arranged close to each other above 9.

E[The electron impact light taken out from the hole 22 provided in the ES sensor 10 passes through the optical waveguide 42, is guided out of the feedthrough 43, and passes through the optical window 44 provided so as not to break the vacuum. , the filter 45 transmits only light having a wavelength specific to the evaporated substance to be measured. This transmitted light is detected by the photomultiplier 46 and becomes a current, which is then converted from IV to EIES rate monitor 47 (for example, Inficon's 5entinel 200 or Sentinel) to be displayed as a rate. ing. Further, the EIES rate monitor 47 outputs an evaporation source control voltage 50 for controlling the vapor flow to a set rate, a supply voltage 52 to the filament 25 in the EIES sensor 10, and a supply voltage 51 to the photomultiplier 46. There is.

EB gun 1 controlled by evaporation source control voltage 50! 5i is vaporized by an EB gun 49 connected to a source 48.

The rate monitor 47 has a built-in variable gain amplifier for performing calibration using the crystal sensor 41.

EI calibrated using the crystal sensor 41 as described above
The ES sensor IO makes it possible to accurately control the evaporation rate of Si evaporated from the EB gun to a predetermined value.

〔Effect of the invention〕

As explained above, according to the present invention, an electron source that generates accelerated electrons and a reflecting mirror disposed near a passage irradiated with one shot of accelerated electrons are provided, and the electrons emitted in the front direction are The shock light is directly taken out to the outside and detected, and the electron impact light emitted in the front direction b' is reflected in the front direction using this reflector and taken out to the outside for detection. Evaporated matter can be detected with good sensitivity.

[Brief explanation of drawings]

Fig. 1 is a block diagram of one embodiment of the present invention, Fig. 2 is a block diagram of another embodiment of the present invention, Fig. 3 is a system block diagram of vacuum evaporation rate control, and Fig. 4 is a perspective view of a conventional sensor. show. In the figure, 10 is a sensor, 12 is a bottom plate, 14.15 is a side plate, 16.17 is an end plate, 20 is a steam flow path, 22 is a hole, 25
27 is a filament, 27 is an anode electrode, 29 is a converging electrode, 30 is a flat reflecting mirror, and 31 is a concave reflecting mirror.

Claims (1)

[Scope of Claims] A sensor for monitoring vacuum evaporation configured to measure the evaporation rate by detecting the emission intensity of electron impact light generated when evaporated matter excited by electron impact returns to a metastable state, It is equipped with an electron source that generates accelerated electrons to bombard the evaporated material, and a reflector placed near the area where the evaporated material is irradiated with the accelerated electrons generated by this electron source, and is emitted in the back direction. A sensor for monitoring vacuum evaporation, characterized in that it is configured to measure the deposition rate by detecting the intensity of the electron impact light that is focused by reflecting the electron impact light in the front direction using a reflecting mirror.