JP3453190B2 - Vacuum evaporation method and vacuum evaporation apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a vacuum deposition of a flexible plastic film having various functions, which can be used in the fields of food packaging, pharmaceutical packaging, electronic device component packaging, tobacco packaging, photoengraving, photosensitive photographic materials and the like. TECHNICAL FIELD The present invention relates to a vacuum vapor deposition method and a vacuum vapor deposition apparatus suitably used for processing.

[0002]

2. Description of the Related Art In recent years, the surface of a flexible plastic film is coated with a metal or a metal oxide by a vacuum vapor deposition method to improve decorative properties, gas barrier properties, chemical resistance, wetting properties, magnetic properties, electrical conductivity, dimensional stability, etc. With added functionality, it has come to be used in fields such as food packaging, pharmaceutical packaging, electronic device component packaging, tobacco packaging, photoengraving and photosensitive photographic materials. In particular, aluminum vapor-deposited films have come to be widely used for decoration and packaging. Recently, silicon oxide vapor deposition film has been actively researched and developed as a transparent high barrier material with little environmental pollution, and it is expected that it will be widely spread, and demand for the development of metal oxide vapor deposition technology will increase day by day. It's getting stronger.

In response to the spread of these applications, it has become necessary to reduce mass production and processing costs. Therefore, it is practical to reduce the processing time by increasing the evaporation temperature to increase the processing speed, widen the width of the film to be mounted to increase the area that can be produced in one processing step, and extend the processing length. As a result, vapor deposition machines have become larger. In order to extend the processing length, the evaporation material crucible must be enlarged so that a large amount of evaporation material can be charged at one time, or a storage space for evaporation material can be provided in the vacuum chamber so that it can be continuously supplied. It has been. In the case of continuously supplying a meltable evaporation material such as aluminum, as shown in FIG. 4, a boat-shaped evaporation source (heating unit for evaporating the evaporation material is heated by a resistance heating method to a temperature at which the evaporation material is evaporated or more). The method of continuously supplying the evaporation raw material processed into a wire is widely used in Europe and America. Further, when a sublimable evaporation material such as silicon oxide is used, as shown in FIG.
As shown in FIG. 6, a method for continuously supplying an evaporating raw material heated to a sublimation temperature or higher by an electron beam heating method to continuously supply it, or an apparatus as shown in FIG.
No. 52768, disclosed in JP-A-2-277774), a method of continuously supplying an evaporation raw material has been adopted.

However, in any of the methods, the evaporation raw material is supplied to the raw material heater which is the evaporation source (heating part for evaporating the evaporation raw material) without preheating it, so that the evaporation raw material is heated from a temperature close to room temperature to an evaporation temperature. It is heated rapidly. Therefore, heating of the evaporation raw material becomes insufficient, and it is difficult to obtain a sufficient evaporation rate (vapor deposition processing rate). When the evaporation raw material is a composite composition, the composition itself may be damaged. Further, if the power supplied to the heater of the evaporation source or the electron beam is increased in order to compensate for the insufficient evaporation rate, a large deviation will occur in the temperature distribution of the evaporation raw material. As a result, in the case of a fusible raw material such as aluminum, splash (evaporative splash) is caused by bumping. This splash has a problem that it reaches the vapor deposition film and causes troubles such as defects of the vapor deposition film, damage of the base film, and a phenomenon of mixing of foreign matter. Moreover, in the case of a composite composition of sublimable raw materials such as silicon oxide (particularly powder molding), the occurrence of splash and rapid gas release (in the case of powder molding raw materials or when impurities of low evaporation temperature are included) ), And further, the composite composition (particularly the forming raw material) which is the evaporation raw material is cracked, which causes rise in the pressure in the vacuum chamber, mixing of impurities and fluctuations in the evaporation rate.

As a result, when the pressure in the vacuum chamber rises, the quality of the silicon oxide vapor deposition film deteriorates, and the evaporation rate (as a result, the vapor deposition processing rate) also decreases. Further, the occurrence of splash causes troubles such as defects in the vapor deposition film, damage to the base film and the phenomenon of mixing of foreign matter as described above, and cracking of the composite composition, which is the evaporation raw material, occurs in the heater for continuous supply vapor deposition. In this case, a "clogging" phenomenon occurs, which hinders long-time vapor deposition processing due to continuous supply of evaporation raw materials. Fluctuations in the evaporation rate occur irregularly for each heater of the evaporation sources arranged in a line, which makes control of the vapor deposition film thickness and the like unstable, resulting in deterioration of the quality of the vapor deposition film. As described above, the conventional vapor deposition method capable of continuously supplying the evaporation raw material has a problem that it is difficult to achieve both productivity and vapor deposition film quality.

[0006]

DISCLOSURE OF THE INVENTION The present invention is a vacuum vapor deposition method for continuously supplying a sublimable evaporation raw material containing silicon oxide in order to realize mass production, and has a high evaporation rate (as a result, vapor deposition processing speed) and a stable evaporation rate. It is to provide a vacuum deposition method that achieves both of the above qualities.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sublimation evaporation raw material containing silicon oxide in a vacuum vapor deposition method in which the sublimation evaporation raw material is substantially continuously supplied.
It can be achieved by a vacuum deposition method characterized by preheating at a temperature rising rate of up to 300 ° C / min. It is a further object of the present invention that, in a vacuum vapor deposition apparatus that supplies a sublimable evaporation material containing silicon oxide substantially continuously, it is preheated at a temperature rising rate of 100 to 300 ° C./min before the evaporation material is evaporated. This can be achieved by a vacuum vapor deposition device characterized by having a preheating unit.

In the present invention, as the vacuum vapor deposition apparatus for substantially continuously supplying the evaporation raw material, as shown in FIG. 5, the evaporation raw material heated to the sublimation temperature or higher by the electron beam heating system is continuously moved to move continuously. Supply device,
As shown in FIG. 6, JP-A-1-252768 and JP-A-2
The device described in Japanese Patent Publication No. 277774 is cited.
In the present invention, as a method of preliminarily heating the continuously supplied evaporation raw material in the preheating unit, if the method can be used in a vacuum state and the evaporation raw material can be heated to a predetermined temperature within a predetermined time There is no particular limitation, and conventionally known methods such as direct resistance heating, indirect resistance heating, direct high frequency induction heating, indirect high frequency induction heating, radiation heating, and electron beam heating can be used.

The temperature of the preheating section may be directly controlled, but it is not necessary to do so. When the temperature of the preheating unit is directly controlled, the control method includes PID control, proportional control, fuzzy control and the like. As a temperature measuring method therefor, a method using a conventionally known thermometer such as a thermocouple thermometer and a radiation thermometer can be used. FIG. 2 shows a schematic diagram of a system in which a direct resistance heating evaporation source (a heating unit for evaporating an evaporation material) and a direct resistance heating preheating unit are PID-controlled by a radiation thermometer. Further, FIG. 3 shows a schematic diagram of a system in which a direct resistance heating evaporation source (a heating unit for evaporating evaporation material) and a preheating unit for high-frequency induction heating are PID-controlled by a radiation thermometer. When the temperature of the preheating unit is not directly controlled, a method of integrating the evaporation source (heating unit for evaporating the evaporation raw material) and the preheating unit as shown in FIG. 1 can be mentioned. The method of integrating the evaporation source and the preheating unit is a preferable method because the apparatus can be simple and inexpensive.
Even when this method is used, the temperature of the evaporation source is controlled. Therefore, the temperature difference between the evaporation source and the temperature of the preheating unit can be grasped correctly, so that the temperature of the preheating unit can be effectively controlled.

In the present invention, it is an essential condition to supply the evaporation raw material smoothly and continuously, and the evaporation raw material must be preheated so as not to disturb it. In other words, the temperature of the preheating section depends on the characteristics of the evaporation raw material (sublimability),
It should be set in consideration of the heat capacity, the thermal conductivity of the evaporation raw material, the feed rate of the evaporation raw material, and the like. Specifically, when the evaporation raw material is a sublimable raw material having low thermal conductivity such as silicon oxide, the temperature of the preheating portion is 200 ° C. higher than the sublimation temperature of the raw material.
It must be above the low temperature and below the temperature 50 ° C above the sublimation temperature. If the temperature of the preheating unit is higher than this range, the evaporation raw material will sublimate in large amounts before reaching the evaporation source, so the evaporation raw material itself will be reduced and efficient evaporation will not be performed. .

The temperature of the preheating section for preheating the evaporation raw material is within the range of conditions in order to increase the evaporation rate of evaporation by the evaporation source as much as possible and to further enhance the effect of solving the problem to be solved by the present invention. It is preferable that the temperature is as high as possible. The temperature of the preheating section is 673 to 923 ° C., and further 903 to 9 ° C., when silicon monoxide, which is a sublimable raw material having low thermal conductivity, is vacuum-deposited under a pressure of 1 × 10 ⁻² Pa.
23 ° C is preferred. When a mixture of silicon and silicon dioxide having a low thermal conductivity is vacuum-deposited under a pressure of 1 × 10 ^-2 Pa, the temperature is 923 to 1173 ° C., and further 1153 to 117.
3 ° C is preferred. When the evaporation raw material contains a silicon oxide such as SiO ₂ which is a sublimable raw material having low thermal conductivity, if the temperature rising rate for preheating is rapid, as a result, the occurrence of splash, rapid gas release, and evaporation raw material Cause cracking, increase of pressure in vacuum chamber, mixing of impurities, fluctuation of evaporation rate, etc. Therefore, when the evaporation raw material contains a silicon oxide such as SiO ₂ , the temperature rising rate at the time of preheating the evaporation material needs to be about 100 to 300 ° C./min.

The sublimation evaporation raw material is not particularly limited as long as it is a raw material used in a vacuum vapor deposition apparatus for continuously supplying the raw material, and Si and SiO, Si ₃ O ₄ , Si ₂ O ₃ ,
A mixture of one or more substances selected from silicon and silicon oxides such as SiOx (X = 1 to 2) containing SiO ₂ , a mixture of silicon and / or silicon oxide and a metal and / or a metal compound, Examples include chemical bonds. Among them, silicon oxide such as SiO ₂ may be crystalline or amorphous. Examples of the metal compound include metal oxides and metal fluorides. As the metal oxide, magnesium oxide,
Calcium oxide, barium oxide, aluminum oxide, titanium oxide, zirconia oxide, sodium oxide, potassium oxide, tin oxide, indium oxide, magnesium oxide-silicon dioxide co-oxide (forsterite, steatite) ), Aluminum oxide-silicon dioxide co-oxide (mullite) and the like. Examples of the metal fluorides include alkaline earth metal fluorides such as magnesium fluoride, calcium fluoride, and barium fluoride, and alkali metal fluorides such as sodium fluoride and potassium fluoride.

[0013]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to the following examples without departing from the gist thereof. The test method for the vapor-deposited film obtained in the examples is as follows. Oxygen barrier property: According to ASTM D 3985, the oxygen gas permeability was measured using OXTRAN-TWIN manufactured by Modern Controls, Inc., USA. Appearance: Defects in the deposited film of the obtained deposited film and inclusion of foreign matter were visually evaluated.

[Example 1] As shown in FIG.
The vacuum vapor deposition apparatus described in Japanese Patent Publication No. 252768 has a preheating unit (made of a boron nitride composite sintered body) integrated with an evaporation source. The heating method of the preheating unit is the same resistance heating method as the heating method of the evaporation source. Note that the temperature control of the preheating unit was not performed independently, but the method that relied on the temperature control by the radiation thermometer of the evaporation source was adopted. Next, an equimolar mixture of silicon and silicon dioxide (amorphous) was compression molded to obtain a cylindrical molded product having a diameter of 40 mm and a height of 35 mm. The obtained molded product is continuously supplied to the preheating section integrated with the evaporation source at a supply rate of 5 mm / minute from the evaporation source supply mechanism, and the evaporation source is resisted under a vacuum of 1 × 10 ^-2 Pa. The film was heated to 1350 ° C. by heating (at that time, the temperature of the preheating part was measured by using a radiation thermometer and found to be 1170 ° C.), and silicon oxide was vacuum-deposited on a polyethylene terephthalate film having a thickness of 12 μm. Under the conditions, the processing speed was 50 m / min, and vacuum deposition processing was performed for 1 hour. No splash was observed during the vacuum deposition process for 1 hour. The thickness of the vapor-deposited film was about 1000 Å when measured using a quartz-type film thickness monitor.

[Embodiment 2] As shown in FIG.
In the vacuum vapor deposition apparatus described in Japanese Patent Publication No. 252768, a preheating unit (made of graphite) that is separate from the evaporation source.
Was set up. The heating method of the preheating section is a high frequency induction heating method. The temperature control of the preheating unit was performed by a radiation thermometer separately from the evaporation source. Next, a mixture of silicon monoxide and magnesium oxide (mixing ratio 90 mol%: 10 mol%) was compression molded to obtain a cylindrical molded product having a diameter of 40 mm and a height of 35 mm. The obtained molded product is continuously supplied from the evaporation material supply mechanism to the preheating section which is a separate body from the evaporation source at a supply rate of 10 mm / minute, and the evaporation source is supplied under a vacuum of 1 × 10 ^-2 Pa. It was heated to 1300 ° C. by the resistance heating method, and at the same time, the preheating part was heated to 920 ° C. Thickness 12μ
m-polyethylene terephthalate film was vacuum-deposited with a silicon-magnesium composite oxide. Under the conditions, the processing speed was 50 m / min, and vacuum deposition processing was performed for 1 hour.
No splash was observed during the vacuum deposition process for 1 hour. The thickness of the vapor-deposited film was about 1000 Å when measured using a quartz-type film thickness monitor.

Example 3 An equimolar mixture of silicon and silicon dioxide was compression molded to obtain a cylindrical molded product having a diameter of 40 mm and a height of 35 mm. The obtained molded product was continuously supplied from the evaporation source supply mechanism of the vacuum evaporation apparatus similar to that of Example 2 to the preheating unit which was separate from the evaporation source at a supply rate of 10 mm / min, and 1 × 10 5. ^The evaporation source was heated to 1300 ° C. by resistance heating under a vacuum of ⁻² Pa, and at the same time, the preheating section was heated to 116 ° C.
Heated to 5 ° C. From the temperature of the preheating part and the temperature of the evaporation source, the temperature rise rate of the evaporation raw material molding was calculated to be 200 ° C.
/ Minute. Silicon oxide was vacuum-deposited on a polyethylene terephthalate film having a thickness of 12 μm, and vacuum deposition was performed for 1 hour at the processing speed of 50 m / min under the conditions. No splash was observed during the vacuum deposition process for 1 hour. The thickness of the vapor-deposited film was about 1000 Å when measured using a quartz-type film thickness monitor.

Comparative Example 2 Silicon oxide was vacuum-deposited on a polyethylene terephthalate film having a thickness of 12 μm in the same manner as in Example 3 except that the preheating part was heated to 600 ° C. The temperature rising rate of the evaporation raw material molded product was calculated from the temperatures of the preheating part and the evaporation source, and it was 700 ° C./minute. Under the conditions, the processing speed was 50 m / min, and vacuum deposition processing was performed for 1 hour. However, generation of splash was observed during the vacuum deposition process for 1 hour. The thickness of the vapor-deposited film was about 1000 Å when measured using a quartz-type film thickness monitor.

Comparative Example 1 A silicon-magnesium composite oxide was vacuum-deposited on a polyethylene terephthalate film having a thickness of 12 μm in the same manner as in Example 2 except that the preheating section was not heated. The temperature of the evaporation source at the time of vacuum deposition processing was 1300 ° C., which was the same as that in Example 2, but the preheating part at that time did not perform heating, and it was 60 ° C. when measured with a thermocouple thermometer. Machining speed is 50 under that condition
When the vacuum vapor deposition process was continued at m / min, generation of splash was observed, and after about 30 minutes, the molded material as the evaporation raw material was damaged and continuous supply of the raw material was impossible, so the vacuum vapor deposition process was stopped.

The oxygen barrier properties and the appearance of the last portion of the vapor deposition process of the vapor deposition films obtained in the examples and comparative examples were evaluated. The results are shown in Table 1.

[Table 1]

[0020]

EFFECTS OF THE INVENTION According to the present invention, insufficient heating of the evaporation raw material, decrease in evaporation rate, damage to the raw material molding itself, generation of splash due to bumping, rapid gas release, pressure increase in vacuum chamber, inclusion of impurities Vacuum deposition can be performed without troubles such as fluctuation of evaporation rate and evaporation rate, and a high quality vapor deposition film can be obtained.

[0021]

[Brief description of drawings]

FIG. 1 is a side view of a preheating unit and an evaporation source integrated with the evaporation source of the present invention.

FIG. 2 is a side view of a preheating unit and an evaporation source which are separate from the evaporation source of the present invention.

FIG. 3 is a side view of a preheating unit and an evaporation source which are separate from the evaporation source of the present invention.

FIG. 4 is a side view of a conventional electron beam heating evaporation source.

FIG. 5 is a side view of a conventional evaporation source.

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-5-93271 (JP, A) JP-A 1-252768 (JP, A) JP-A-49-84930 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C23C 14/00-14/58 H01L 21/203

Claims (2)

(57) [Claims] 1. A vacuum vapor deposition method for substantially continuously supplying a sublimable evaporation raw material containing silicon oxide, which comprises heating the evaporation raw material at a temperature rising rate of 100 to 300 ° C./min in advance. Characteristic vacuum deposition method. 2. A vacuum vapor deposition apparatus for substantially continuously supplying a sublimable evaporation raw material containing silicon oxide, and preheating for preliminarily heating at a temperature rising rate of 100 to 300 ° C./min before vaporizing the evaporation raw material. A vacuum deposition apparatus having a portion.