JPH0230754A - Vacuum deposition method - Google Patents

Abstract

PURPOSE:To minimize the adhesion of a substance to be vacuum-deposited to a substrate by splash and to obtain a vacuum-deposited film hardly causing exfoliation by setting a meshy plate having a higher m.p. than the substance to be vacuum-deposited on a melting boat. CONSTITUTION:A substance 12 to be vacuum-deposited such as SiO2 is put in a melting boat 11. A meshy plate 13 having a higher m.p. than the substance 12 is set on the boat 11 so as to cover the substance 12. The splash of the substance 12 is prevented by the plate 13. The substance 12 is then evaporated and vacuum-deposited on a substrate 16.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a vapor deposition method.

(Prior Art) Generally, in a method of depositing a vapor deposition material (dielectric or metal) on a substrate, heating and melting of the vapor deposition material is performed, for example, by
As described in 114 Film Handbook, Chapter 2, "Vacuum Deposition Method," resistance heating method, electron beam heating method, etc. are used.

For example, if SiO, which has a low melting point, is used as the vapor deposition material, the third
As shown in the figure, granular S is applied to the port-shaped resistance heating element 1.
i04 is mounted, a current of several tens of amperes is passed through the attached electrode 3 to melt the SiO4, and the SiO4 is placed in a vacuum (I
It is deposited on the substrate at a deposition rate of several people/S using XIO-'Torr).

Furthermore, when Cr, which has a relatively high melting point, is used as the material to be deposited,
As shown in FIG. 4, Cr6 is put into the cooling crucible 5, and C
An electron beam 8 is irradiated from an electron gun 7 to r6 to deposit it on the substrate.

[Problem to be solved by the invention]

In the resistance heating method that vaporizes SiO using the resistance heating element described above, depending on the magnitude of the current flowing through the attached electrode when controlling the melting of the vaporized SiO material, SiO spills from the resistance heating element and is deposited on the substrate. It may not be possible to deposit the required absolute amount. Furthermore, control of the deposition rate tends to become unstable;
When the evaporation rate becomes too high, there is a problem in that the evaporation material adheres to the substrate side as "bubbles" called "splatters" (see Table 1, Conventional Example 1).

On the other hand, in the electron beam heating method in which Cr is heated with an electron beam, a temperature difference occurs between the electron beam irradiated surface of C' and the inside of C', and since Cr is a sublimable evaporation substance, Cr If you do not perform vapor deposition while releasing gas by incorporating a soaking effect when heating, Cr will suddenly receive high heat and will bump together with the gas, resulting in the problem of "stubbles" popping out and adhering to the substrate side as described above. there were. Such "bulbs" can be several tens to 100 μm in size and cause film peeling, or in the case of lenses, become an obstruction in the optical field of view, resulting in defects that cause poor appearance and reduced yield. (See Table 1, Conventional Example 2).

The present invention has been made in view of the above problems, and includes:
The object of the present invention is to provide a thin deposition method that minimizes the "flying" of the deposited material and obtains a constant deposition rate using electron beam melting, which can digitally vary the melting power and melting size.

[Means and effects for solving the problems] In order to achieve the above object, in the vapor deposition method of the present invention, when vacuum-depositing a vapor deposition substance onto a substrate, the vapor deposition substance is placed on the upper surface of the melting boat so as to cover the vapor deposition substance. A mensch-like plate material with a higher melting point is installed to evaporate the above deposited substance.

That is, the deposition material Si is heated using a high voltage and low current electron gun heating method.
When evaporating O, granular SiO is placed in a box-shaped boat made of Mo or W, which has a higher melting point than SiO, and 10 to 20μ of W or Ta is placed on the top of the boat to cover the SiO.
A net-like plate of m mesh size is arranged, and the vapor deposition material is irradiated with an electron beam from above the net-like plate. In such a case, the temperature of the net-like plate, the bottom of the boat, and the surrounding area rises to approximate the temperature of the irradiated surface, so that a uniform heating effect works during the melting of SiO and gas release, and a constant evaporation rate is maintained, and the evaporation material is constantly The evaporation of uniform ultrafine particles (in order) is carried out. Furthermore, 10~
Since large bump-like vapor deposition substances of 30 μm or more are captured, "flying" adhering to the substrate surface is prevented to a minimum.

In addition, the evaporation material Cr is
When depositing Cr, granular Cr is placed in a box-shaped boat made of W or Ta, which has a higher melting point than Cr, and a net-like plate of 10 to 20 μm mesh size made of W or Ta is placed on the top of the boat to cover the Cr. , in which an electron beam is irradiated onto the vapor deposition material from above the net-like plate, and the same effect as the high-voltage, low-current electron gun heating method described above can be obtained.

(Example] Embodiments of the present invention will be described in detail below with reference to the drawings.

(First Example) As shown in FIG. 1, a cooling hearth liner 10 used for vacuum melting of a substance as an electron gun heating method is made of Mo or W. I! A box-shaped boat 11 of 1 is installed. Next, granular 5tO12 is put into the board 11 as the first substance, and 5j0 is placed on the top surface of the boat 11 so as to cover the 5iOI2.
10-20μm made of W or Ta which has a higher melting point than 12
A mensch-sized net-like plate 13 is arranged. And inside the chamber I X 10-5 ~ 5 X I O-'T
After evacuation to a vacuum level of
The evaporation substance 12 was evaporated by irradiating the evaporation substance 12 from above 3, and was deposited on the substrate 16. At this time, the deposition rate is 5 to 50
It was done in person/sec.

In this method, BK-7 glass temporary 16 (n
= 1.516), and the deposition rate was set to 50 persons/Sec.
Table 1 shows the evaluation of film formation performed with the settings set to 1 (see Example 1).
Shown below. That is, when the appearance was observed using an optical microscope (x200), there was almost no adhesion of "flying particles", with only a few particles having a particle diameter of 1 to 2 .mu.m being observed. Also,
The deposition rate was also confirmed at the same time and was 28 to 30 people/sec.
Met.

According to this example, it was possible to prevent the evaporation material from "flying" and to perform the evaporation while controlling the evaporation rate to a set value.

(Second Embodiment) As shown in FIG. 2, a box-shaped boat 17 made of W or Ta is disposed on a cooling hearth liner 10 similar to that of the first embodiment. Next, granular Cr18 is put into the board 17 as a vapor deposition material, and 10~10~10~10~10~100% of W or Ta, which has a higher melting point than Cr18, is placed on the top surface of the boat 17 so as to cover the C18.
A net-like plate 19 having a mesh size of 20 μm is arranged.

Then inside the chamber l x 10-S~5 x 10
After evacuation to a vacuum level of -' Torr, a current of several tens of amperes is charged, and the electron beam 21 from the electron gun 20 is irradiated onto the vapor deposition material 18 from above the net-like temporary material 19 to evaporate the vapor deposition material 18 and deposit it on the substrate 22. Deposited. At this time, the deposition rate is 3
~10 people/sec.

In this method, BK-7 glass temporary 22 (n
Table 1 (see Example 2) shows the evaluation of film formation performed using the following method (=1.516) and setting the deposition rate to 6 people/see. That is, when the appearance was observed using an optical microscope (x200), only 6 to 7 "flying" particles with a particle size of 1.-3 μm were observed scattered, indicating that the film was formed well. Also, when we checked the deposition rate at the same time, it was 5 to 6 people/see.
The deposition rate and path distance were set at -.

In addition, as shown in the above-mentioned first embodiment and second embodiment,
Due to the prevention of "splash" for sublimable deposition materials and the ease of controlling the deposition rate, deposition materials conventionally performed by resistance heating deposition methods, such as Al, Ce0, etc.
z, CeFe, TizO: +.

TiO, etc. or evaporation substances performed by electron beam evaporation, such as Taz○s, Ti0z, Zr0zA2□
Oz, SiO□, etc. can also be used without being limited by the sublimation and melting properties of the vapor deposition material, and can be carried out while producing the same effects and effects as in the above embodiments.

Table 1 [Effects of the Invention] As described above, according to the vapor deposition method of the present invention, it is possible to minimize the "splash" of the vapor deposition material adhering to the substrate side, thereby reducing the vapor deposition film that is difficult to peel off. is formed, and the appearance quality can be improved. Furthermore, since the deposition rate can be controlled to be constant, the optical properties (refractive index, absorption rate) or crystallinity of the deposited film can be controlled as desired.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the first embodiment of the first-place method of the present invention;
The figure is an explanatory diagram of a second embodiment of the one-layer deposition method of the present invention, and FIGS. 3 and 4 are explanatory diagrams of a conventional vapor deposition method. 11...Boat 12...Vapour-deposited substance 13...Mensch-like plate Figure 1 Patent applicant Olympus Optical Co., Ltd.

Claims (1)

[Claims] (1) A vapor deposition method characterized in that when a vapor deposition substance is vacuum-deposited on a substrate, a mesh plate material having a higher melting point than the vapor deposition substance is placed on the top surface of a melting boat so as to cover the vapor deposition substance, and the vapor deposition substance is evaporated. .