JPH0160546B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method and apparatus for forming a thin film with high vapor deposition efficiency. In recent years, products in which a thin film of metal or the like is layered on a substrate by vacuum evaporation, ion plating, sputtering, etc. have been developed and put into practical use in various fields. The materials for the thin film can now be applied to a wide variety of materials, such as noble metals, magnetic materials, polymeric substances, organic lubricants, etc., and the major technical challenge currently facing is how to form thin films at low cost. be.
Taking this problem as an example of the vacuum evaporation method mentioned above, it is generally understood that increasing the vapor deposition efficiency, that is, the ratio between the amount of evaporated material and the amount actually deposited on the substrate, greatly contributes to solving the problem. It is recognized. Therefore, instead of the conventional method of emitting a vapor flow consisting of particles of metal etc. from the evaporation surface with an approximately Cos ⁿ distribution using an open type hearth with a relatively wide evaporation opening, a method with a relatively small evaporation opening is used. However, a method has been proposed in which a sealed hearth is used to radiate the steam flow in a highly directional manner as the internal pressure increases. However, although good results have been obtained with the sealed hearth for materials such as Ga and Zn as evaporation sources, it is difficult to use materials such as Fe, Ni, and Co, which are usually easily available. Hearth materials such as W,
It reacts with Ta, Mo, C, BN, MgO, Al ₂ O ₃ , etc. at high temperatures and is easily damaged, making it extremely difficult to put it into practical use. On the other hand, in addition to the sealed hearth method, there has been proposed a method for manufacturing electrical substrates as disclosed in Japanese Patent Application Laid-Open No. 153411/1983 as a method for improving the directivity of the vapor flow and increasing the vapor deposition efficiency. However, in this proposed method, a part of the vapor flow emanating from the open hearth as described above at a wide angle is made to impinge on a heated reflector made of a high melting point metal plate such as W. This method is characterized in that the vapor flow is directed toward a substrate, and in terms of the vapor flow whose emission or radiation direction is modified by the reflector, the coercive force after adhering to the substrate is increased. However, no solution was found in improving the deposition efficiency.
Before reflecting the vapor stream in a desired direction,
A large amount of metal particles are attached to and captured on the reflective surface,
As a result, the drawback that reflection efficiency and vapor deposition efficiency gradually decrease has not been solved. Therefore, the inventors of the present invention have discovered that even in an open hearth that diverges at a relatively wide angle, it is possible to efficiently focus and direct the entire vapor flow in a desired direction, and the vapor deposition efficiency is at least equivalent to that of the sealed hearth system. As a result of extensive research into methods for forming vapor-deposited thin films that can achieve higher performance than above, the method and apparatus of the present invention have been put to practical use. SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the conventional methods described above, and to provide a method and apparatus for forming a deposited thin film that is stable for a long time and is efficient. Such an object of the present invention is to: In a vacuum atmosphere; to control a vapor flow obtained by heating an evaporation source between the evaporation source and the object to be evaporated by a partition wall in a vapor flow diffusion prevention means. While passing through the space, a portion of the vapor flow that collides with the inner surface of the partition wall, which is heated to a temperature higher than the evaporation surface temperature of the evaporation source or to a temperature at which evaporation particles attached to a solid surface can be re-evaporated, is After refracting the evaporation direction by the inner surface of the partition wall so as to merge with the vapor flow and converging the evaporation distribution of the entire evaporation air flow, evaporation particles in the vapor flow are evaporated onto the object to be evaporated. and in a vacuum atmosphere; an evaporation source, a hearth for housing the evaporation source, a heating means for heating and evaporating the evaporation source, and at least an upper part for passing vapor flow. vapor flow diffusion prevention means comprising a partition wall member having a lower opening area and whose inner surface can be heated to a temperature higher than the evaporation surface temperature of the evaporation source or to a temperature at which evaporation particles attached to a solid surface can be re-evaporated; ,
The vapor flow diffusion preventing means efficiently focuses the evaporation distribution of vapor particles contained in the vapor flow without causing quantitative loss of the vapor particles by the inner surface of the partition wall member. This is achieved by a thin film forming apparatus characterized by: Hereinafter, embodiments of the present invention will be described in detail based on the attached drawings. In FIG. 1, 1 communicates with a vacuum exhaust system 22 whose internal vacuum level is generally 10 ^-2 to 10 ^-8 Torr.
3 is a known material such as W, Ta, C, Cu,
An open hearth made of Mo, Al ₂ O ₃ , BN, etc.; 4 is an evaporation source made of a magnetic material housed in the hearth 3; depending on the application, Ag, Cr, Co, Fe, Ni,
Co-Ni, Mn-Al, Fe-Ni, Gd-Tb-Fe alloys, etc. are used. Reference numeral 5 denotes an evaporation source heating means of an electron beam heating type arranged near the hearth 3. The above-mentioned hearth 3 is not limited to the so-called open type in which the evaporation source 4 has an upper opening that allows evaporation over a relatively wide area; It may be a limited closed hearth. Further, the evaporation source heating means 5 is not limited to only the electron beam heating method, and other known methods such as resistance heating, high frequency induction heating, etc. can be adopted. Reference numeral 6 denotes a vapor flow diffusion prevention means disposed above the evaporation source 4, and the vapor flow expansion prevention means 6 includes:
A lower opening area 7 for a vapor inlet whose opening area faces the entire evaporation surface of the evaporation source 4, and an upper opening area 8 for a vapor outlet having a relatively small opening area above the opening area 7. A partition wall member 9 whose longitudinal cross section is approximately eight-shaped as a whole (see FIG. 2 for details);
(see FIG. 3), and a heat shield member 1 covering the outer surface of the partition wall member 9 except for each opening area 7 and 8.
0. Note that the partition wall member 9 is made of W, Ta, Mo, Ti,
It is made of a high melting point metal material such as Pt, and a part of its frame is connected to the heating power source 12. Furthermore, it is preferable that the inner circumferential surface of the partition wall member 9 be finished as smooth as possible. The heat shield member 10 is made of a metal material with relatively high thermal conductivity, such as Cu, and has a cooling coil 11 wound around its outer peripheral surface. Reference numeral 13 denotes a cooling can which is rotatably disposed above the vapor flow diffusion prevention means 6, and supports a base W (for example, a flexible band-shaped material such as a polyester film) in a curved shape on the lower outer peripheral surface of the cooling can. It provides driving guidance. 14, the partition means 6 and the cooling can 1;
A net-like beam focusing auxiliary electrode made of a high melting point material such as W, Ta, Mo, stainless steel, etc. is disposed between 3 and near a predetermined evaporation surface on the lower surface of the substrate W, and is provided with a negative potential. is provided, and its effective area is positioned so as not to deviate from a predetermined deposition area on the lower surface of the base body W. Reference numeral 15 denotes a mask disposed below the cooling can 13 to prevent the vapor flow V from depositing on the lower surface of the base W at an unspecified angle. In the apparatus of the present invention, the main parts of which are constructed as described above, first, the inside of the casing 1 is brought to a desired degree of vacuum within the range of 10 ^-2 to 10 ^-8 Torr via the evacuation system 2. While maintaining the temperature, the evaporation source heating means 5 is energized to heat the evaporation source 4 in the hearth 3.
When continuously heated, the evaporation source 4 gradually evaporates from its evaporation surface into a vapor flow V of metal particles. Note that during the evaporation, a small portion of the metal particles are ionized and ionized together with other metal particles.
It diverges and rises with a Cos ⁿ distribution. Next, all of the vapor flow V enters the inside of the partition wall member 9 from the lower opening area 7 of the partition wall member 9 in the vicinity of the evaporation source 4 whose evaporation distribution is not relatively expanded. I'll go. The evaporation surface temperature of the evaporation material 4 differs depending on the material, evaporation processing conditions, etc., but is usually about 1200°C or higher for Ag materials; about 1300°C or higher for Cr materials;
The Co material has a specified surface temperature of approximately 1800° C. or more that is kept approximately constant by the heating means 5, while at least the inner circumferential surface temperature of the partition wall member 9 is the specified evaporation surface temperature or the evaporation particle temperature. Since the heating power supply 12 maintains a substantially constant temperature at which re-evaporation is possible even if the particles adhere to and solidify on the solid surface, the evaporated particles contained in the vapor flow V are kept on the partition wall. Even if it repeatedly collides with the inner circumferential wall surface of the member 9, it will not react with the inner circumferential wall surface and adhere or solidify,
It continues to rise inside the member 9 and eventually passes through the upper opening region 8 with its evaporation distribution becoming significantly narrower than the initial one. The vapor flow V that has passed through the outlet 8 has its focused distribution state strengthened by the beam focusing auxiliary electrode 14 and is given a desired incident angle, and after passing through the net-like voids, is efficiently The base W
vapor deposited on the surface of Note that it is desirable that the incident angle be in a range of about 45 degrees or more in order to improve the coercive force. position) may be set appropriately. Further, instead of the beam focusing auxiliary electrode 14, it is also possible to apply a ring-shaped or rod-shaped focusing auxiliary electrode, and furthermore, it is also possible to use a ring-shaped or flat-shaped focusing auxiliary electrode on the back surface of the base body W and make it close to the beam focusing auxiliary electrode 14. ,
Furthermore, they may be provided on both sides of the base W. The heat shield member 10 prevents heat radiation from the evaporation source 4, the partition wall member 9, etc., and enables heating with low power, while also preventing the base body W from deteriorating due to radiant heat. Furthermore, if the heat shield member 10 itself is abnormally heated, it is also possible to send a refrigerant such as water to the cooling coil 11 to cool it, if necessary. FIG. 4, FIG. 5, FIG. 6, and FIG. 7 each show modified examples of the partition wall member 9 based on the present invention. The partition wall member 19 shown in FIG.
7 and the steam outlet 18 have the same opening area and are formed into a hollow rectangular parallelepiped shape, and furthermore, the four walls are simplified to three or two walls, that is, other than the entrances and exits 17 and 18. It is also possible to increase other aperture areas. The partition wall member 29 shown in FIG. 5 has been changed to a cylindrical partition wall surface in accordance with the shape of the round plate-shaped hearth 3, and is different from the partition wall member 3 in FIG.
Reference numeral 9 indicates a wall surface having a cross-sectional shape (\-shape) opposite to that of the partition wall member 9 shown in FIGS. 1 to 3. Any of the partition wall members 9, 19, 29, 3 mentioned above
9, if the inner circumferential wall surface that the vapor flow V collides with is finished smooth and the inner circumferential wall temperature is heated to the specified evaporation surface temperature or re-evaporation temperature, the Cos ^n- shaped evaporation occurs. The vapor flow V is reliably focused by its inner circumferential wall surface.
can be efficiently incident on the substrate W and vapor-deposited. Moreover, the vapor flow diffusion prevention means 6 is integrated with the hearth 3 without any gap, so that
Furthermore, heat radiation can be suppressed. In that case, a beam irradiation hole may be provided so that the heating electron beam can reach the hearth 3, or a window for monitoring and replenishing the evaporation source 4 may also be provided. Furthermore, the partition wall member 9 can be heated by an electron beam type, induction type, or resistance type heating means, and the material is not limited to those mentioned above, and may be made of MgO, BN composite, Al, etc. _{2O3 ,}
Ceramic materials such as ZrO ₂ may also be used. The present invention described above is applicable not only to the vacuum deposition method but also to methods such as ion plating and sputtering, and the substrate W may be made of, for example, cellulose triacetate, polycarbonate, polyimide, polyethylene terephthalate, polycarbonate, plastic film or sheet, etc.
Glass, ceramics, etc. can also be used. Next, the novel effects of the present invention will be further clarified through Examples and Comparative Examples. [Example] The evaporation efficiency was measured according to the three conditions (~) shown in the following table using evaporation sources of Ag material and Co material. [Comparative Example] The vapor deposition efficiency was measured under the same conditions as in the examples under each of the above conditions except that the partition wall member was removed.

【table】

[Table] Comparing the vapor deposition efficiencies of Examples and Comparative Examples, it became clear that the present invention (Examples) could actually improve the vapor deposition efficiency by 20 to 40 times.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the entire apparatus for carrying out the method of the present invention, FIG. 2 is an enlarged sectional view of the main part in FIG. 1, FIG. 3 is a perspective view showing a part of FIG. 2, and FIG.
5 and 6 are explanatory views of modified examples of the apparatus of the present invention, respectively. 3 is a lease, 4 is an evaporation source, 6 is a vapor flow diffusion prevention means, V is a vapor flow, and W is a base body.

Claims (1)

[Claims] 1. In a vacuum atmosphere; a vapor flow obtained by heating an evaporation source is transferred between the evaporation source and the object to be deposited in a space defined by a partition wall in a vapor flow diffusion prevention means. A part of the vapor flow that collides with the inner surface of the partition wall, which is heated to a temperature higher than the evaporation surface temperature of the evaporation source or to a temperature at which evaporation particles attached to the solid surface can be re-evaporated, is transferred to other vapors. The evaporation direction of the vapor flow is refracted by the inner surface of the partition wall so as to merge with the vapor flow, and the evaporation distribution of the entire vapor flow is focused, and then the evaporation particles in the vapor flow are vapor-deposited onto the object to be vaporized. A method for forming a thin film characterized by forming a thin film using the following steps. 2. The thin film forming method according to claim 1, wherein the evaporation source is made of a noble metal material, a magnetic material, an organic lubricant, or a polymer material. 3. An apparatus for carrying out the thin film forming method according to claim 1, in a vacuum atmosphere;
an evaporation source, a hearth for housing the evaporation source, a heating means for heating and evaporating the evaporation source, and at least an upper and lower opening area for passing vapor flow, the inner surface of which has a temperature higher than the evaporation surface temperature of the evaporation source or a solid surface; vapor flow diffusion prevention means comprising a partition wall member that can be heated to a temperature at which evaporated particles adhering to the evaporation particles can be re-evaporated; A thin film forming apparatus characterized in that the inner surface of a wall member efficiently focuses the evaporation distribution of evaporation particles contained in the vapor flow without causing a quantitative loss of the evaporation particles. 4. The thin film forming apparatus according to claim 3, wherein the partition wall member is provided with the vapor flow diffusion prevention means whose outer periphery is covered with a heat shield member. 5. The thin film forming apparatus according to claim 3, wherein the evaporation source is made of a noble metal material, a magnetic material, an organic lubricant, or a polymer material. 6. The thin film forming apparatus according to claim 3, wherein the vapor flow diffusion prevention means is substantially continuously integrated with the hearth.