JPS6053746B2 - Method for forming heterogeneous thin films by reactive deposition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reactive vapor deposition method in which a deposited thin film is formed on the surface of a substrate composition while the substrate composition is moved along a transfer path, and the deposited thin film is exposed to a reactive gas at this time. .

In particular, the present invention relates to methods of forming heterogeneous thin films by such reactive deposition. One of the known methods of forming heterogeneous thin films using reactive deposition methods such as those described above involves monotonically varying the deposition rate along the transport path.
This method utilizes the fact that when the deposition rate changes monotonically, the characteristics of the substance produced by the reaction between the deposition substance and the reaction gas also change monotonically. At this time, it is also known that if the incident density of the reaction gas is further monotonically changed along the transport path, the degree of change in the characteristics of the reaction product can be enhanced. Such a known method is achieved, for example, by the vacuum deposition apparatus illustrated in FIG.

In this vacuum evaporation apparatus, a long film-like base structure 20 is placed in a vacuum evaporation tank 21 by an unwinding roller 2 at the upper left.
After being deflected by the first deflecting roller 23, it is transferred horizontally from left to right while contacting the lower surface of the horizontally extending stationary guide plate 24, and further deflected by the second deflecting roller 25. It is wound up by the winding roller 26 on the upper right side. Horizontal transfer path 27 for the base structure 20 along the lower surface of the guide plate 24
The vapor deposited substance A is placed at an appropriate distance directly below the left edge of
For example, an evaporation source 28 of chromium is arranged. Horizontal transfer path 2
A first shielding plate 29 and a second shielding plate 30 are provided below and close to the evaporation source 28, and the first shielding plate 29 does not reach the vapor deposition substance A or the substrate structure 20 to the left of the vertically upper part of the evaporation source 28. Make a cutoff to make it happen. Further, the second shielding plate 30 is connected to the horizontal transfer path 27.
From a position near the right end of
Avoid reaching 0. According to such an arrangement, the vapor deposition material A flying between the limit shown by the vertical broken line 31 and the limit shown by the diagonal broken line 32 in FIG. . In this case, the vapor deposition rate D for each surface portion of the film-like substrate structure 20 is:
Clearly, this portion decreases monotonically from position 33 at limit 31 to position 34 at limit 32.

However, in the vacuum evaporation apparatus shown in FIG. 1, the reaction gas G is introduced into the vacuum evaporation tank 21 through the gas introduction pipe 35 during the evaporation operation. Therefore, for each surface portion of the base structure 20, in areas where the deposition rate D is high, the amount of the vapor deposited substance A deposited is large compared to the amount of the arriving reaction gas G, so that the reaction product of A and G with a large amount of A is produced. B is formed and the deposition rate D
On the contrary, in places where the amount of A is small, a reaction product B containing less A is formed. The physical properties of the thin film thus formed on each surface portion of the base structure change in the direction of its thickness. Specifically, the substance that forms the thin film consists of the reaction product B with a large amount of A on its base surface (the surface in contact with the base component), and the content of A increases as it approaches the outer surface (the surface opposite to the base component). Quantity decreases. A non-uniform thin film is thus formed. In the above-mentioned known example, the gas introduction pipe 35 may be configured and arranged so that the incident density of the reaction gas G monotonically increases from the position 33 to the position 34 along the transfer path 27. The change in A content in the thickness direction increases.

In FIG. 1, reference numeral 36 indicates a light emitter/receiver of the optical monitor, 37 indicates an auxiliary shielding plate, and 38 indicates a shutter. The guide plate 24 has a cooling water passage 39 by which the substrate structure 20 is cooled to a constant temperature in the transfer passage 27, that is, during the vapor deposition operation. In the known method using the apparatus shown in FIG. 1, in order to achieve a monotonous change in the deposition rate, only that of the deposition material A evaporated from the deposition source 28 flies toward the right range from the vertical limit 31. The deposited material A that is used and flies from the vertical limit 31 toward the left range is blocked by the shielding plate 29.

Therefore, substantially only half of the deposited material A is effectively used. Conventional methods of varying the deposition rate along the transport path obviously create many evaporation sources below the transport path. This can also be achieved by sequentially arranging these evaporation sources so that the evaporation rate of the evaporation material is sequentially reduced. However, operating the evaporation source at low deposition rates significantly reduces efficiency, as is known to those skilled in the art. An object of the present invention is to provide a highly efficient method that eliminates the drawbacks of the conventional method of forming a heterogeneous thin film by reactive vapor deposition as described above.

To achieve this objective, the method for forming a heterogeneous thin film according to the present invention forms a vapor deposited thin film on the surface of a substrate structure while moving the substrate structure along a transfer path, and at this time, the vapor deposited thin film is exposed to a reactive gas. The reactive vapor deposition method is characterized in that the temperature of the substrate structure is varied along the transport path.

According to one embodiment, the substrate arrangement along the transfer path is moved by moving the substrate composition along the surface of a stationary guide plate in the transfer path and by varying the temperature of the guide plate positionally along its surface. A temperature change of the composition is achieved. According to another embodiment, the substrate configuration along the transfer path is moved so as to sequentially contact a plurality of rotating cylinders, and the temperatures of the rotating cylinders are different from each other. A temperature change in the composition is achieved.

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

The vacuum evaporation apparatus shown in FIG. 2 for carrying out the method of the present invention has many components that are substantially the same as the conventional one shown in FIG. omit or simplify explanation.

In the apparatus shown in FIG. 2, the evaporation source 28a is located substantially directly below the center of the transfer path 27. The evaporation substance A evaporated from the evaporation source 28a flies along the base structure 20 that is moving along the transfer path 27 between the oblique limits 31a and 32a, which are substantially longitudinally symmetrical. The guide plate 24 has a cooling water passage 39a near its left end, and the many embedded heaters 40 on the right side of the guide plate 24a are arranged so that the distance between them gradually becomes narrower.
buried inside. In the method of the present invention using the vacuum evaporation apparatus shown in FIG. 2, cooling water is flowed into the cooling water passage 39a and the embedded heater 40 is energized during the vacuum evaporation operation.

In this way, the temperature of the guide plate 24a increases monotonically from left to right along its lower surface, and therefore the temperature of the base structure 20 that is transferred while contacting the lower surface of the guide plate 24a increases along the transfer path 20. For example, as shown by the solid line U in FIG. 3, it changes monotonically. In FIG. 3, X is the transport distance of the base structure, E corresponds to position 33, and F corresponds to position 34.
T represents the temperature of the base structure. V in FIG. 3 indicates the temperature change of the base structure in the conventional case. Note that the monotonous increase in temperature of the base structure 20 along the transfer path 27 as described above is just an example of the present invention, and the present invention also includes changing the temperature of the base structure in another manner. Ru.
At that time, the arrangement and spacing of the cooling water passage 39a and the embedded heater 0 are changed. The reason why a non-uniform thin film can be formed on the surface of the base structure 20 due to the temperature change of the base structure as described above will be explained next.

The base component 20 is a metal foil (for example, A1 foil, Cu foil,
An example will be exemplified in which a black chromium selective absorption film made of CrOx (x varies) is formed on the surface of a Ni foil or Ni-coated stainless steel foil.

When Cr is adopted as the vapor deposition substance A evaporated from the evaporation source 28a, and 02 is introduced as the reaction gas G from the gas introduction pipe 35, a metal oxidation reaction occurs to form a coating of chromium oxide CrOx on the surface of the base structure. Ru. At this time, the film composition Cr
Ox (expressed in atomic ratio) is expressed by the formula (1) as is known. However, let's stop here.

In the above equations (1) and (2), N(02) indicates the frequency of incidence of 02 on the surface of the base structure expressed as the number of C2 molecules per unit area and unit time, and N(Cr) indicates the frequency of incidence of 02 on the surface of the base structure expressed as the number of C2 molecules per unit area and unit time. α represents the frequency of incidence of Cr on the surface of the substrate component, expressed as the number of Cr atoms per hour.

represents the condensation coefficient of 02 molecules, E represents the activation energy for chemisorption of oxygen, ΔE represents the activation energy for desorption of oxygen, R represents the gas constant, and T represents the substrate configuration expressed in absolute temperature. The temperature of the object 20 is shown.

However, in equation (1), α.・Exp(IP) is a monotonically increasing function of temperature T in the case of oxidation reaction of Cr, and therefore, if N(02)/N(Cr) remains unchanged, x also depends on the temperature T of the base structure. becomes a monotonically increasing function. As is clear from this relationship, if the temperature T of the substrate structure is changed along the transfer path, the CrOx thin film formed on the surface of the base component x
changes in the thickness direction. This results in a heterogeneous thin film whose composition changes in the direction of the thickness of the thin film. The above holds true in general cases other than the oxidation of Cr, and the vapor deposited substance A
The proportion of A and G in the reaction product B constituted by the reaction gas G and the reaction gas G is varied in the thickness direction of the thin film by changing the temperature of the substrate structure along the transport path, This allows the formation of a non-uniform thin film.

Since the method of this invention is configured as described above,
Unlike the conventional one shown in FIG. 1, it is not necessary to place the evaporation source 28 unevenly so that only a part of the vapor-deposited material A that will evaporate and fly is utilized; instead, the evaporation source 28a is placed centrally as shown in FIG. Substantially most of the deposited substance A that is produced or evaporated can be used effectively.

In the vacuum deposition apparatus shown in FIG. 4, a long film-like substrate structure 20 is unwound from an unwinding roller 22 at the upper left in a vacuum deposition tank (not shown), and deflecting rollers 23a, 23b and 23c, the first rotary cylinder 41, which can rotate around the horizontal axis, advances along the lower circumferential surface of the first rotary cylinder 41, and after being deflected by the deflection roller 42, the first rotary cylinder 41, which can rotate around the horizontal axis, It advances along the lower circumferential surface of the second rotating barrel 41a, and after being deflected by the deflecting roller 42a, it proceeds along the lower circumferential surface of the third rotating barrel 41b which can rotate around the horizontal axis. After being deflected by deflection rollers 25a, 25b, and 25c, it is wound up by a winding roller 26 on the upper right side.

First rotating barrel 41, second rotating barrel 41a, and third rotating barrel 4
Evaporation sources 28b, 28c and 28d of vapor deposition substance A are arranged below 1b, respectively. Shielding plates 29a, 43a
, 43b and 30a, the evaporation source 2
The vapor deposition substance A from the evaporation source 8b reaches the surface of the base structure 20 between the positions 33a and 34a of the first rotating cylinder 41, and the vapor deposition substance A from the evaporation source 28c reaches the surface of the base structure 20 between the positions 33a and 34a of the second rotating cylinder 41a.
The evaporation substance A from the evaporation source 28d reaches the surface of the base structure 20 between positions 33c and 34c of the third rotary cylinder 41b. The first rotating barrel 4) 1 has a cooling water passage 39b arranged along its circumference, and the second rotating barrel 41a has a number of embedded heaters 40a arranged along its circumference. The three-rotation cylinder 41b has many embedded heaters 40b arranged along the circumference at narrower intervals than the embedded heaters 40a. Furthermore, the deflection roller 42a has an embedded heater 40c. Reference numeral 35 indicates a gas introduction pipe for the reaction gas G. In the vacuum evaporation apparatus shown in FIG.
is mainly the first rotary cylinder 41 between positions 33a and 34a.
Transfer path portion 27c1 along the second rotary cylinder 41a between positions 33b and 34b along the transfer path portion 27b1 and position 3
It is composed of a transfer path portion 27d along the third rotary cylinder 41b between 3c and 34c.

In order to achieve the method of the present invention, cooling water is passed through the cooling water passage 39b during the vapor deposition operation, and the embedded heaters 40a, 40b are
, 40c are energized. In this way, the rotating cylinder 41,
The temperatures of 41a and 41b change each other, and more specifically, they increase in this order, thereby causing the temperature of the base structure 20 to change along the transfer path, as shown by W in FIG. 5, for example. Here, C, D, E, F, G, H are at positions 33a, 34a
, 33b, 34b, 33c, and 34c, respectively. Also, X and T have the same definitions as in FIG. Due to such temperature changes, the above-mentioned figures 2 and 3
It is clear that a non-uniform thin film is formed as in the case shown in the figure. In the method of the present invention shown in FIGS. 4 and M5, it is necessary to reduce the evaporation rate at every evaporation source, especially compared to the conventional method in which many evaporation sources are arranged to sequentially reduce the evaporation rate of the deposition material. High efficiency can be obtained because there is no

[Brief explanation of drawings]

FIG. 1 is a diagrammatic illustration of a vacuum evaporation apparatus used to implement a conventional method for forming a heterogeneous thin film, and FIG. 2 is an illustration of an embodiment of a vacuum evaporation apparatus used to implement a method for forming a heterogeneous thin film according to the present invention. 3 is a graph showing the temperature change of the substrate structure in the apparatus of FIGS. 1 and 2, and FIG. FIG. 5, an illustrative diagram of the embodiment, is a graph showing the temperature change of the base structure in the apparatus of FIG. 4.

Claims (1)

[Claims] 1. A reactive vapor deposition method in which a deposited thin film is formed on the surface of a substrate composition while the substrate composition is moved along a transfer path, and the deposited thin film is exposed to a reactive gas at this time. A method for forming heterogeneous thin films by reactive deposition, characterized in that the temperature of the film is varied along the transport path. 2. The temperature change of the base structure along the transfer path is controlled by moving the base structure along the surface of a stationary guide plate in the transfer path and changing the temperature of the guide plate positionally along the surface. A method as claimed in claim 1 to achieve. 3 Achieving a temperature change of the base structure along the transfer path by moving the base structure so as to sequentially contact a plurality of rotating cylinders in the transfer path so that the temperatures of the rotating cylinders are different from each other. A method according to claim 1.