JPH04308077A - Method for controlling irradiation by electron gun - Google Patents

Abstract

PURPOSE:To stabilize a vaporization pattern and to improve uniformity by forming the polar coordinates of the beam point of an electron gun with respect to the surface of a vapor-deposition material and changing the respective coordinate components to circularly sweep the material with the electron beam. CONSTITUTION:A vapor-deposition material 4 in a vacuum deposition device is irradiated by an electron gun 5, heated and vaporized. The polar coordinates of the beam point P are formed with respect to the surface of the material 4, and the distance R from the center 0 of the surface of the material 4 and its angle to the straight line passing through the center are used as the coordinate components. At least the coordinate component is changed at a set rate to circularly sweep the surface of the material 4 with an electron beam 6.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] This invention relates to heating and vaporizing a deposition source material in a vacuum evaporation apparatus by irradiating an electron beam from an electron gun to generate a deposition source (vapor flow).
This invention relates to a method for controlling an electron beam of an electron gun.

0002

2. Description of the Related Art In a vacuum evaporation apparatus, a evaporation source material is heated and evaporated in a vacuum space, and the vaporized evaporation source is deposited on a substrate or the like to form a film. As one method of heating a deposition source material, an electron beam heating method is generally well known in which an electron beam is output from an electron gun, and the deposition source material is directly heated by irradiation with the electron beam.

[0003] In order to evaporate the evaporation source material evenly over the entire surface with such an electron beam, the electron beam is swept. When performing this sweep, conventionally, in the method disclosed in Japanese Unexamined Patent Publication No. 2-66166, the surface of the vapor deposition source material is swept in the X and Y directions perpendicular to each other.
A method is used to uniformly irradiate the rectangular surface of the deposition source material by converting the electron beam into rectangular coordinates and sweeping the electron beam at high speed in the X direction and at low speed in the Y direction. There is.

0004

[Problem to be Solved by the Invention] The evaporation pattern from the evaporation source material is a cone-shaped distribution that radiates from an approximate point source into the vacuum space above it, but it is necessary to stabilize this pattern. , the deposition source material has a circular melt zone,
Ideally, it should be heated in a circular manner. Furthermore, by separately controlling the heating near the outer periphery and the center of the circle, the evaporation pattern is stabilized and controllability is improved.

However, in the above-mentioned conventional method, the sweep in the X direction and Y direction on the surface of the evaporation source material is performed independently, and the surface of the evaporation source material is irradiated in a rectangular shape, so that the above aim cannot be achieved. .

An object of the present invention is to improve the electron beam irradiation control method so that the surface of the evaporation source material can be swept circularly, thereby stabilizing the evaporation pattern and improving controllability. .

[0007]

[Means for Solving the Problem] For this purpose, in the invention of claim 1, the electron beam is swept in a polar coordinate irradiation control pattern.

That is, in the electron gun irradiation control method of the present invention, the beam point of the electron gun to the surface of the evaporation source material is set at a distance R (radius) from the center position of the surface of the evaporation source material and passing through the center position. By expressing it in polar coordinates whose coordinate component is an angle θ (declination) from a predetermined straight line (original line), and by changing at least the coordinate component θ at a set speed,
It is characterized in that the electron beam from the electron gun is swept in a substantially circular shape on the surface of the evaporation source material.

In the invention of claim 2, the coordinate component θ is changed at a constant speed, and the coordinate component R is gradually increased from the minimum value to the maximum value at a constant speed in synchronization with the change in the coordinate component θ. The electron beam is swept in an outward spiral over the surface of the source material.

In the invention of claim 3, the coordinate component θ is changed at a constant speed as in the invention of claim 2, but on the contrary, the coordinate component R is gradually decreased from the maximum value to the minimum value at a constant speed. This causes the electron beam to sweep in an inward spiral over the surface of the source material.

In the invention of claim 4, the coordinate component θ is changed at a constant speed, and each time the coordinate component θ exceeds a predetermined value,
By gradually changing the coordinate component R, the electron beam is swept concentrically on the surface of the deposition source material.

In the invention of claim 5, the coordinate component θ is changed at a constant speed, and the coordinate component R is changed in synchronization with the change in the coordinate component θ using the formula (R2 ・cos 2 θ/a2 )+(R2 ・
sin 2 θ/b2 )=1...■ However, by changing the conditions such that a≠b is satisfied, the electron beam is swept in an elliptical shape on the surface of the evaporation source material.

The invention according to claim 6 is characterized in that the rate of change of the coordinate component θ is made different depending on the coordinate component R.

[0014]

[Operation] With the above configuration, in the invention of claim 1, the electron beam irradiation from the electron gun is performed on the surface of the evaporation source material at a distance R from the center position and an angle θ from a straight line passing through the center position. The electron beam is controlled based on the polar coordinate component, and at least the coordinate component θ is changed to sweep the electron beam over the surface of the evaporation source material, so the evaporation source is swept approximately circularly, and its evaporation pattern is stabilized. , uniformity is also improved.

In the invention of claim 2, the coordinate component θ changes at a constant speed, and the coordinate component R gradually increases from the minimum value to the maximum value at a constant speed, so that the electron beam is directed outward at the surface of the evaporation source material. Can be swept in a spiral. Further, in the invention of claim 3, the coordinate component θ changes at a constant speed, and the coordinate component R gradually increases from the maximum value to the minimum value at a constant speed, so that the electron beam can be swept inwardly in a spiral manner. can. Further, in the invention of claim 4, the coordinate component θ changes at a constant speed, and each time the coordinate component θ exceeds a predetermined value, the coordinate component R gradually changes, so that the electron beam is swept concentrically. Furthermore, in the invention of claim 5, the coordinate component θ changes at a constant speed, and in synchronization with the change in the coordinate component θ, the coordinate component R changes under the condition that satisfies the above formula (■). is swept in an elliptical shape on the surface of Therefore, similar effects can be obtained with these inventions.

In the sixth aspect of the invention, since the rate of change of the coordinate component θ differs depending on the coordinate component R, the heating capacity can be changed at the inner and outer peripheral portions of the surface of the vapor deposition source material.

[0017]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings.

FIG. 3 shows a vacuum evaporation apparatus according to Embodiment 1 of the present invention, in which 1 is a vacuum vessel, inside of which a crucible 2 made of heat-resistant metal is placed on the lower side, and an electron beam 6 is placed on the side of the crucible 2. and an electron beam 6 from this electron gun 5.
A deflection magnet 12 for deflecting is provided. On the other hand, a substrate holder 16 that holds a substrate (not shown) to be vapor-deposited is disposed in the upper part of the vacuum chamber 1 at a position directly above the crucible 2, and between the substrate holder 16 and the crucible 2. A shutter 17 is arranged to control vapor deposition from the vapor deposition source onto the substrate by passing or blocking a vapor flow 4a from the vapor deposition source material 4, which will be described later.

The crucible 2, the electron gun 5, and the deflection magnet 12 have well-known structures, which will be explained in detail with reference to FIG. A vapor deposition source material 4 to be vapor-deposited onto the substrate is filled inside. The electron gun 5 includes a cathode electrode 7 attached to the side surface of the crucible 2 via an insulator 7a,
A first plate electrode 8 is arranged at a predetermined interval on the side thereof, and is made of a vertical plate part made up of a part of the crucible 2; The cathode electrode 7 is heated by a filament. Each plate electrode 8,
Openings 9 and 11 are formed in each of the electrodes 10, and the negative electrode of a high-voltage DC power source is connected to the cathode electrode 7, and the positive electrode of the same power source is connected to both plate electrodes 8 and 10 (crucible 2), respectively. , 8, and 10, electrons ejected from the cathode electrode 7 are accelerated by the potential of the plate electrodes 8, 10, and an electron beam 6 is generated.

On the other hand, the deflection magnet 12 has a core 13 and
It consists of a coil 14 wound around the core 13, and by supplying a deflection current to the coil 14, a deflection magnetic field for deflecting the electron beam 6 is generated, and this deflection directs the electron beam 6 to the aperture 9, 11 to irradiate the evaporation source material 4 in the housing section 3 to heat the evaporation source material 4, and by supplying a scanning current to the coil 14,
By sweeping the electron beam 6 over the surface of the evaporation source material 4 in the storage section 3, the evaporation source material 4 is heated to generate an evaporation flow 4a. 15 Crucible 2
This is a cooling water passage formed so as to surround the accommodating portion 3 inside.

Returning to FIG. 3 again, the operations of the electron gun 5 and deflection magnet 12 are controlled by a control device 21. In this embodiment, the sweep of the electron beam 6 on the surface of the evaporation source material 4 in the housing section 3 is performed as follows. That is, as shown in FIG. 1, the beam point P of the electron gun 5 on the surface of the vapor deposition source material 4 is set at a distance R from a predetermined center position O on the surface of the vapor deposition source material 4 and a predetermined distance passing through the center position O. By expressing the angle θ from the straight line OX in polar coordinates (R, θ) as a coordinate component, and changing the coordinate components R and θ in synchronization with each other, the electron beam 6 from the electron gun 5 is directed to the evaporation source material 4. Sweep it in a circular pattern on the surface.

When the beam point P on the surface of the evaporation source material 4 is represented by polar coordinates (R, θ) and rectangular coordinates (X, Y) with X and Y components in two mutually orthogonal directions, polar coordinates (R, θ) and rectangular coordinates (X, Y) are X=
There is a relationship Rcos θ...■ Y=Rsin θ...■ The beam point P can be changed by changing the coordinate components R and θ instead of the X and Y components. Specifically, in this embodiment, as shown in FIG. 4, the coordinate component θ of the polar coordinates (R, θ) is changed at a constant speed, and the coordinate component θ of the coordinate component R is changed at a constant speed.
It is characterized in that the electron beam 6 is swept outwardly in a spiral shape on the surface of the evaporation source material 4 by increasing it gradually at a constant speed from the minimum value Rmin to the maximum value Rmax in synchronization with the .

Therefore, in this embodiment, the electron beam 6 from the electron gun 5 is distributed on the surface of the evaporation source material 4 in polar coordinates (R, θ), and the coordinate component θ
increases and changes at a constant speed, whereas the coordinate component R changes in time to the minimum value Rm in synchronization with the change in the coordinate component R.
It gradually increases from in to the maximum value Rmax at a constant speed. For this reason, the electron beam 6 from the electron gun 5 is swept in an outward spiral on the surface of the evaporation source material 4 in the housing section 3, as shown in FIG. In this way, the surface of the evaporation source material 4 is swept circularly, and the evaporation pattern is stabilized and its uniformity is improved.

FIG. 5 shows Example 2, in which:
Of the polar coordinates (R, θ) that determine the sweep pattern of the electron beam 6 from the electron gun 5, the coordinate component θ is increased and changed at a constant speed as in Example 1, but the coordinate component R is, on the contrary, the maximum value Rmax. to the minimum value Rmin at a constant speed.

Therefore, in this embodiment, the coordinate component θ
increases and changes at a constant speed, whereas the coordinate component R gradually decreases at a constant speed from the maximum value Rmax to the minimum value Rmin in synchronization with the change in the coordinate component R.
The electron beam 6 is swept in an inward spiral over the surface of the evaporation source material 4 in the housing 3 . Therefore, the same effects as in the first embodiment can be achieved.

FIG. 6 shows Example 3, in which the coordinate component θ is changed at a constant speed, and this coordinate component θ is 2nπ (n is an integer).
Each time the coordinate component R is exceeded, the coordinate component R is set to a different set value R1.
, R2, . . . are gradually increased or decreased.

In this embodiment, the coordinate component θ changes at a constant speed, and each time the coordinate component θ exceeds 2nπ, the coordinate component R gradually changes, so that the electron beam 6 is swept concentrically. Therefore, similar effects can be obtained in this embodiment as well. Note that the set value of the coordinate component θ when changing the coordinate component R is not limited to 2nπ, and can be changed as appropriate.

FIG. 7 shows a fourth embodiment, in which the electron beam 6 is swept in an elliptical shape. That is, the ellipse is
In rectangular coordinates (X, Y), (X2 / a2 ) + (Y2 / b2 ) = 1...■
However, it is expressed as a≠b, and by substituting the above equations (■) and (2) into this equation (2), the polar coordinate representation of the ellipse shown in the above equation (■) can be obtained.

Therefore, by changing the coordinate components R and θ so as to satisfy the equation (2), the electron beam 6 can be swept in an elliptical shape on the surface of the evaporation source material 4. At this time, similarly to the third embodiment, the coordinate component θ is 2nπ(n
By gradually increasing or decreasing the coordinate component R each time the coordinate component R exceeds an integer (integer), the electron beam 6 can be swept in a concentric ellipse as shown by the virtual line in the figure.

Note that, unlike the above embodiments, the coordinate component θ
By making R variable and changing the rate of change depending on the coordinate component R, it is possible to change the heating ability of the electron beam 6 at the inner and outer peripheral portions of the surface of the vapor deposition source material 4. For example, power can be concentrated on the outer circumference, or conversely, power can be concentrated on the inner circumference.

Furthermore, the beam point set by the coordinate components R and θ and the output of the electron gun 5 may be combined in advance to form a pattern.

[0032]

As described above, according to the first aspect of the invention, the beam point of the electron gun with respect to the surface of the evaporation source material is made into polar coordinates, and at least the coordinate component θ is changed, so that the electron beam from the electron gun is By sweeping the surface of the evaporation source material, the surface of the evaporation source is swept circularly by the electron beam, making it possible to stabilize and improve the uniformity of the evaporation pattern, which is originally cone-shaped.

According to the second aspect of the invention, the coordinate component θ is changed at a constant speed, and the coordinate component R is gradually increased from the minimum value to the maximum value at a constant speed. can be swept in an outward spiral on the surface of the Further, according to the third aspect of the invention, the coordinate component θ is changed at a constant speed, and the coordinate component R is gradually increased from the maximum value to the minimum value at a constant speed, so that the electron beam is swept in an inward spiral. Can be done. Further, according to the invention of claim 4, the coordinate component θ is changed at a constant speed, and each time the coordinate component θ exceeds a predetermined value, the coordinate component R is gradually changed, so that the electron beam point can be swept concentrically. Can be done. In the fifth aspect of the invention, since the coordinate components R and θ are changed according to the equation (2), the electron beam can be swept in an elliptical shape.

According to the sixth aspect of the invention, since the rate of change of the coordinate component θ is varied depending on the coordinate component R, it is possible to change the heating capacity at the inner and outer peripheral portions of the surface of the vapor deposition source material.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the basic principle of an electron beam irradiation pattern on the surface of a vapor deposition source material in Example 1.

FIG. 2 is a partially cutaway perspective view showing the configuration of a deposition source generation mechanism.

FIG. 3 is a front view schematically showing the configuration of a vacuum evaporation apparatus.

FIG. 4 is a plan view showing an actual irradiation pattern in Example 1.

FIG. 5 is a plan view showing an actual irradiation pattern in Example 2.

FIG. 6 is a plan view showing an actual irradiation pattern in Example 3.

7 is a plan view showing an actual irradiation pattern in Example 4. FIG.

[Explanation of symbols]

1...Vacuum container 2... Crucible 4...Vapor deposition source material 5...Electron gun 6...Electron beam 16...Substrate holder 21...Control device R, θ...polar coordinate components

Claims (6)

[Claims] 1. A method of irradiating a deposition source material with an electron gun in order to heat and evaporate a deposition source material in a vacuum evaporation apparatus, the beam point of the electron gun relative to the surface of the deposition source material being set at the center position of the surface of the deposition source material. Expressed in polar coordinates whose coordinate components are a distance R from the center and an angle θ from a straight line passing through the center position, and by changing at least the coordinate component θ at a set speed, the electron beam from the electron gun is directed to the surface of the evaporation source material. An electron gun irradiation control method characterized by sweeping the electron gun in a substantially circular shape. 2. The electron beam is deposited by changing the coordinate component θ at a constant speed and gradually increasing the coordinate component R from a minimum value to a maximum value at a constant speed in synchronization with the change in the coordinate component θ. 2. The electron gun irradiation control method according to claim 1, wherein the electron gun irradiation is swept in an outward spiral on the surface of the source material. 3. Evaporating the electron beam by changing the coordinate component θ at a constant speed and gradually decreasing the coordinate component R from the maximum value to the minimum value at a constant speed in synchronization with the change in the coordinate component θ. 2. The electron gun irradiation control method according to claim 1, wherein the electron gun irradiation is swept in an inward spiral on the surface of the source material. 4. The electron beam is swept concentrically on the surface of the evaporation source material by changing the coordinate component θ at a constant speed and changing the coordinate component R each time the coordinate component θ exceeds a predetermined value. The electron gun irradiation control method according to claim 1, characterized in that: 5. The coordinate component θ is changed at a constant speed, and the coordinate component R is changed in synchronization with the change in the coordinate component θ using the formula (
R2 ・cos 2 θ/a2 )+(R2 ・sin
The electron gun irradiation control method according to claim 1, characterized in that the electron beam is swept in an elliptical shape on the surface of the evaporation source material by changing the condition such that 2 θ/b2 )=1, but a≠b. . 6. The electron gun irradiation control method according to claim 1, wherein the rate of change of the coordinate component θ is varied depending on the coordinate component R.