JPS6013063B2 - Vacuum deposition method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is characterized in that the melting point of indium oxide, tin oxide, zirconium oxide, silicon oxide, magnesium fluoride, zinc sulfide, etc. The present invention relates to a method for vacuum-depositing a mixture of one or two metal compounds that are absent or have a very high melting point using a resistance heating method.

Conventionally, the method of vacuum evaporating such a sublimation-based metal compound using resistance heating method is '1'. A method in which a compound is added and the metal is heated by direct current heating, ■ Alumina,
A method of heating a refractory inorganic crucible such as berylla by applying electricity from the side and/or bottom of the crucible to a coiled basket-shaped or spirally wound metal heater, '3} above tl}, {
In method 2}, a method using a metal heater coated with a refractory inorganic material is commonly used.

In any of these known methods, if the vapor deposition substance is a sublimation type metal compound, it is very difficult to carry out vacuum deposition at a sufficiently fast rate.

For example, in method ``1'', even if the heater temperature is raised to near the melting point of the heater metal in order to sublimate the vapor deposition substance, sublimation is limited only to the vicinity of the heater, so it is difficult to increase the vapor deposition rate. Because the temperature was high enough, the heater metal itself sublimated, melted, etc., causing damage to the heater and disconnection. Even more inconveniently, the heater metal reacts with the metal compound that is the deposited material, decomposing the deposited material or forming a new metal compound, which may affect the properties of the resulting deposited film, especially It has now happened that the ingredients, structure, etc. of the product are different from the intended ones. In addition, the known methods (■) and (■) can prevent the reaction between the metal heater and the metal oxide that is the adhesive substance, but the difference in expansion coefficient between the refractory and the metal heater, and the cracking of the refractory due to rapid heating. This caused problems in terms of durability. In addition to these methods, in order to increase the evaporation rate of metal compounds, a method has also been used in which the outside of the heating source is coated with a reflective plate made of a high-melting point metal to prevent radiation loss from the heating source and raise the evaporation source temperature. There is. In the above method, even if the evaporation source temperature is raised to near the melting point of either the heating heater or Rubbo, whichever is lower, the Rubbo and/or heater on the side facing the substrate is closed. Therefore, the entire evaporation source material does not have the same temperature, and in particular, the surface of the evaporator, which is the main evaporation surface, suffers a large loss due to Korean radiation, and the temperature is usually much lower than that near the heater. On the other hand, another attempt to increase the evaporation rate is to increase the surface area of the evaporation source material. A sample powder is used for this purpose, but in this case, the surface area is large compared to its volume or weight, and the evaporation rate is also high, but it has the disadvantage that it tends to cause phosphorescence and scattering of the sample. In order to improve the various drawbacks of these methods, electron beam evaporation has recently come into the limelight and has come into widespread use.

This is a method that uses an electron beam to bombard the target material and utilizes the temperature rise that occurs at this time. However, in the electron beam method, the electron beam is focused into a beam with a very small cross-sectional area, so if the evaporation source material is a metal compound with no melting point, evaporation will occur only from the point where the beam hits. The rate of evaporation is usually extremely slow, and is currently causing decomposition of the metal compound. Recently, attempts have also been made to deposit metal compounds onto the largest substrates such as plastic films and paper.

In this case, since the deposition time is particularly long, a large amount of evaporation source material is required, and therefore, increasing the size of the crucible and heater further exacerbates the above-mentioned drawbacks. Additionally, Lubbo encountered unexpected difficulties in increasing the size of the heater. That is, since the upper part of Rubbo and/or the reflector does not reach a sufficiently high temperature, the evaporation source material recrystallizes from this area, and as time passes, it grows and gradually covers the entrance.
After sufficient time has elapsed, the dome can be completely capped and no more defects can be deposited. Figure 1 is a side sectional view of the evaporation source showing this, where 1 is a refractory rubbo, 2 is a heater, 3 is a reflector, 4 is a reflector, 5 is the evaporation source material,
6 is a dome-shaped cover formed by recrystallization of the re-source material of the evaporation source material described above. The present inventor has developed the present invention as a result of research to solve the various difficulties that arise when attempting to perform vacuum deposition of one or more of the above-mentioned metal compounds by sublimation, particularly when attempting to perform long-term deposition. It has been reached. That is, the present invention provides a vacuum coating method in which a crucible filled with a metal compound is heated in a vacuum and the metal compound is newly exposed on the surface of the object to be deposited. This is a vacuum evaporation method characterized by a range of

According to the present invention, the above-mentioned purpose is to use mainly granular porridge as a vapor deposition material, which is made by processing one kind or a mixture of two or more kinds of metal compounds into a mass by powder pressing, coagulation, or other methods.
~1 is achieved using the above materials.

More preferably, this is achieved by heating the material having the above particle size by providing an auxiliary heater above the evaporation crucible. The metal compounds referred to in the present invention include, for example, various metal oxides, nitrides, fluorides, sulfides, or CdSe.
, CaTe, ln mother, lnSb, or a mixture of two or more thereof.

Among them, metal compounds that do not have a melting point or have a very high melting point, especially metal compounds that have a melting point of 1600 pm or higher, such as AI203, Ti63, and Ce. 2. It is particularly effective against nitrides such as San-Hakama-san, Bamo-go-Mai, and Kasamaiso-bu-Go.

When the metal compound is filled in a rubbo and vacuum evaporated, the rubbo materials include AI203, Be○, Zr02, T.
Oxides such as hO2, high melting point metals such as Mo and Ta, or C and BN are preferably used. The metal compound to be filled in the Rubbo is required to be mainly in the form of light blocks of 1 to 1 rib.

This is because when vapor deposition is performed by sublimation of a sample as in the present invention, in order to increase the vapor deposition rate, it is necessary to increase the ratio of surface area to weight. However, if powder with a particle size smaller than one pig is used, the powdered sample may be consumed by bumping before or during heating vapor deposition, resulting in material loss, or the scattered powder may collide with the substrate. This is because it can cause undesirable results. On the other hand, when using a block-shaped material with a particle size larger than IQ■, the surface area is relatively small relative to the weight,
The deposition rate is not fast. Furthermore, since the material is in the form of a block larger than a relatively large body, it is impossible to reach a high enough temperature to reach the inside of the material, and evaporation from the surface facing the substrate is only 4.5 mm. When a block-shaped material having a particle size of 1 to IQ is used as the hollyhock adhesive material, the surface area relative to its weight is sufficiently large, and therefore the evaporation rate is also sufficiently fast. Furthermore, since the particle size is one or more ribs, there is sufficient space between each block, and bumping of the sample does not occur.
Furthermore, these gaps are equivalent to forming a kind of small heat rating, and each of the evaporated particles of 1 to 1 shipboard reaches a sufficiently high temperature and the evaporation rate becomes sufficiently large. In the present invention, one or a mixture of two or more kinds of metal compounds in the form of a block of grains having a length of 1 to 1 yen can be prepared by a conventionally known method.

The form of the mixture of one or more metal compounds to form the film is various, including floc, powder,
It can be obtained in the form of granules, plates, sheets, etc. One or more metal compounds in granular form with a particle size smaller than one leg can be made into one or more blocks by powder pressing, hot pressing, melting, etc. A block-shaped mixture of one or more metal compounds having a particle size of more than one ship can be crushed mechanically using a crusher, crusher, mill, whirlpool mortar, etc., or manually. In addition, metal compounds in the form of plates or sheets can also be made into particles smaller than 1 piece by a suitable method such as crushing or cutting. Generally, the particle size of the mixture is not uniform, and the mixture must be classified with a sieve to separate the particles into particles with an IQ of 1 to 1. Sorting is usually done using sieves. The mixture classified by this method clearly does not contain a mixture with a particle size larger than 1 ship, but it usually contains a certain amount of a mixture with a particle size smaller than 1 ship. It cannot be clearly defined as it depends on the method and degree of Note that the particle size here refers to the maximum size of the particle. Mainly 1 to 1 in the present invention
The particle size of 1 molar means that 3% by weight, preferably 5% by weight or more of the particles have a particle size of 1 to 1 molar. When the mixture is a mixture of two or more metal compounds, it goes without saying that the mixture may be formed at any stage of the above formation steps depending on the purpose. One or more metal compounds having a grain size of 1 to 1 mound are particularly suitable as sublimation-type evaporation source materials because they have a sufficiently large surface area relative to their weight and have appropriate voids between grains. preferable. It is possible to further increase the evaporation rate using the evaporation source material.

For this purpose, an auxiliary heater can be provided in the upper part of the crucible. By providing the auxiliary heater at the top of the crucible, the source material is heated not only from the sides and/or the bottom but also from the top of the crucible, so that the source material evaporates at a very high rate. This method is particularly effective when high-speed deposition is desired, and eliminates some of the disadvantages associated with it. For example, when heating only from the side and/or bottom of the Luppo, the vapor deposition material will be effectively heated on the side and/or bottom of the Lubo near the heater and will evaporate quickly, but the evaporation material filled in the top of the Luppo will be insufficient. After a certain period of time, a cavity forms at the bottom of the rubbo, slowing down the rate of evaporation. In such a case, increasing the heater temperature in order to increase the evaporation rate is not preferable from the viewpoint of the life of the heater, the lupus, and the reflector, and such difficulty can be eliminated by providing an auxiliary heater above the crucible. Also, the disadvantage of forming a dome-shaped lid of evaporated material as seen in FIG. 1 is also eliminated. The shape of the auxiliary heater can be chosen as long as it does not cover the opening of the Rubbo.

For example, it may be a single line, two or more parallel lines, a spiral, or a plate with several holes. Further, the heater can be coated with a refractory material such as alumina or berylla in order to prevent reaction with the evaporation source material or evaporation of the heater itself. As in the method of the present invention, in a vacuum evaporation method in which a sublimation type metal compound is filled in a crucible and the crucible is heated in vacuum to sublimate the metal compound, mainly 1 to 1 are used.
When a rubbo is filled with a metal compound having a particle size of one ship's block, the surface area of the metal compound is large and the metal compound is heated uniformly, so that vapor deposition can be performed at a sufficiently long rate.

In a preferred embodiment, an auxiliary heater is provided above the vapor deposition source to heat the vapor deposition source material not only from the side and/or bottom surface of the rubbo but also from the top, thereby evaporating the filled compound at a high vapor chamber speed. becomes possible. The present invention will be explained in detail below using examples. Example 1
Indium oxide mixed with 7.5% tin oxide was deposited onto a polyester film.

Indium oxide and tin oxide are powders of 40 mesh or less that have been classified with a sieve, and then mixed after weighing.
It was molded using the pressure of the earth. The molded product was fired at 700° C. for 4 hours, crushed in a mortar, and classified with a sieve to produce evaporated materials having various particle sizes shown in Table 1. 7 g of the evaporated substance was filled into an alumina crucible (Japan Bax Metal ■: 20◇×2 crucible with assemble heater) wrapped around a tungsten heater whose side and lower surfaces were coated with alumina. The crucible is a molybdenum reflector (Japan Bax Metal ■:
It was placed inside a three-layer reflector for an assemble heater. For the vacuum deposition, a vacuum coating layer with a built-in film wander mechanism (Nichiden Varian UVD-13 model) was used. The pressure at the start of vapor deposition was 2×10 −5 Ton or less. The deposition rate was calculated from a film thickness meter using a crystal oscillator, a light transmission type film thickness meter, and a film feeding speed. The surface resistance of the film after vapor deposition was measured, and the film was analyzed using crab light X-rays. In Table 1, sample number. 1 is an example according to the present invention,
Same ship. 2.M. 3. Earth. 4 and the gunwale. 5 is a comparative example for comparison with the present invention example. In the experiment, the power required to maintain the deposition rate at 40 A/sec by film thickness measurement using a crystal oscillator and the time required to maintain this deposition rate were measured.

No. In samples having a particle size of 1 to 1, the required power increased as the amount of evaporated material decreased, but it was possible to evaporate until the entire amount of evaporated material was used up. rudder. In the case of a sample having a particle size smaller than 0.4 of 2, the sample boiled off before the deposition rate reached 25 A'sec, making it impossible to continue vapor deposition. M. 3 mainly 0.4~
In the case of a sample with particle size on the 1st side, the deposition rate was 35A/sec.
Some of the sample particles were scattered by bumping when the temperature exceeded 40A/
It was possible to perform deposition at a deposition rate of sec. However, the deposition time is the same as that of the method of the present invention. This is about 1/5 compared to the case of one sample, and it is thought that most of the sample was scattered before it evaporated. M. 4, mainly samples with a particle size of 1 or more, and M.4. It was difficult to obtain a deposition rate of 40 A/sec when one sample of approximately 5 grains and 5 ribs was placed. shame. In the case of sample 4, the deposition rate is 4
0 A/sec was maintained only for the first 8 minutes, and when the current was applied further, the heater was disconnected. In this case, part of the crucible was melted. M. Sample 5 is 40A/se
It is impossible to achieve a deposition rate of 25 A/sec.
The heater was disconnected at a deposition rate of 200 ft, and part of the crucible melted. When the coating was analyzed using crab light X-rays, it was found that the ship. 4th place.
Sample No. 5 contained a large amount of tungsten. “■
, 1 From the above results, when sublimating metal compounds are vacuum-deposited, if particles with a particle size of 1 to 1 mm are used as the evaporation source, all of the evaporation source material can be removed at a high deposition rate. It is clear that the base, Lubbo, and the heater can be vaporized without damage.

Furthermore, since the heater temperature is sufficiently low, impurities are less likely to be included in the coating. Example 2 Indium oxide/tin oxide prepared in the same manner as in Example 1 was vacuum-deposited using the same apparatus as in Example 1.

The grain size of the deposited sample is mainly 1 to 1 centimeter.
Vapor deposition was performed by changing the heater voltage. The striped fruits are shown in Table 2. In Table 2, the gunwale. 9, M. In No. 10, an alumina-coated spiral tungsten heater (Nippon Bucks Metal: F-4) was installed as an auxiliary heater on the upper part of Rubbo, and a voltage of 1.8 V was applied. No. 7. Earth. In the case of 8, Table 2 shows that the heater voltage is 4. Due to starvation, part of Rubbo melted and the heater broke.

Furthermore, as the heater voltage increased, the amount of tungsten contained in the coating also increased. Earth. 9. Ship. In the case of sample No. 10, no dome-shaped crystal growth was observed, and the dust could be deposited until the sample was used up, and the amount of tungsten in the coating was small. From the above results, it is clear that the evaporation rate by the auxiliary heater can be sufficiently increased, and the difficulties associated with long-term evaporation can be eliminated.

[Brief explanation of the drawing]

FIG. 1 shows a central sectional view of the evaporation source. Reference numeral 1 indicates a refractory roof, 2 a heater, 3 a reflector plate, 4 a reflective shield, 5 a source material, and 6 a dome-shaped shield formed by crystallization of evaporated matter.

Claims (1)

[Scope of Claims] 1. In a vacuum evaporation method in which a crucible filled with a metal compound is heated in a vacuum and the metal compound is precipitated onto the surface of an object to be deposited, the particle size of the metal compound is mainly 1 to 10 mm.
A vacuum evaporation method characterized by being within the range of. 2. The vacuum evaporation method according to claim 1, wherein the crucible is heated by heating the side and/or bottom surface of the crucible and heating from the top of the crucible using an auxiliary heater provided at the top of the crucible.