JPH0328372A - Production of thin film - Google Patents

Abstract

PURPOSE:To prevent the curling of a substrate and to obtain a thin film having a good shape by heating the long-sized high polymer substrate coated with a thin film layer in the air without contact with a heat source and sucking the substrate being heated from both sides in its cross-direction. CONSTITUTION:A thin film layer is formed directly or through a base layer on a long-sized high polymer substrate of aromatic polyimide or polyimide. A magnetic recording magnetic material consisting essentially of Co and Cr or Co, Cr and Ni is exemplified as the thin film layer. The substrate 3 coated with the thin film is traveled from a rewinding roll 2 to a winding roll 6 through a guide roller 4, and heated with a far IR heater 5, etc., in the air or the atmosphere having the same or higher content of oxygen than the air without contact with the heat source. The substrate 3 being heated is sucked in the sucking direction 10 in its cross-direction by a suction nozzle 7 from both sides through a vacuum pump (not shown in the figure). Consequently, the substrate 3 is annealed without itself being curled due to the thermal contraction, and a thin film layer having a good shape is formed.

Description

[Detailed description of the invention] Industrial application field This invention relates to a thin film manufacturing method for forming a thin film with an excellent shape.Conventional technology Thin film technology plays a very wide variety of roles in modern society. Thin film substrate materials can be broadly classified into flexible substrates such as polymer films and non-flexible substrates such as glass plates based on their mechanical properties. When using a flexible substrate such as a film, a continuous winding method can be used as a method for mass production of thin films.・A thin film is formed on a substrate by a method such as a sputtering method or a vacuum evaporation method.A method of winding a thin film onto a take-up roll is considered to be a method suitable for mass production. Although it is used in a wide range of fields including recording media, thin film formation methods often involve heat treatment called annealing for the purpose of relaxing internal stress and improving surface hardness after thin film formation. (As shown in FIG. 3, it is possible to use the temperature-raising roller 54 by running the thin-film pre-treated polymer substrate 3 along the temperature-raising roller 54 in the atmosphere, for example, using a winding system. In the case of annealing, the polymer substrate 3 undergoes rapid thermal deformation when it begins to touch the temperature-raising roller and when it comes off the temperature-raising roller, so wrinkles are likely to occur (Also, the surface properties of the thin film after annealing Since it depends on the surface properties of the temperature-raising roller 54, in order to obtain a thin film with good surface smoothness, the surface of the temperature-raising roller 54 must also be smooth.These problems can be avoided by using the temperature-raising roller 54. Direct heating without using the temperature raising roller 54 is effective as a means for heating the polymer substrate 3 with a thin film formed thereon, as shown in FIG.
The problem to be solved by the present invention is that the annealing treatment can be performed by non-contact heating using a wafer. However, when the thermal contraction of the polymer substrate 3 occurs due to the annealing treatment, the polymer substrate 3 on which the thin film has been formed will shrink. In general, curling occurs with the substrate inside.The higher the annealing temperature, the stronger the curl, and reducing curl and providing a sufficient annealing effect are contradictory issues. In this case, the curl in the width direction of the substrate becomes even stronger than in the case where the annealing process is performed using the temperature raising roller 55.

The present invention (1) aims to solve the problems of the prior art.Means for solving the problems The present invention provides a method for forming a thin film layer on a long polymer substrate directly or via an underlayer. In a thin film manufacturing method in which the polymer substrate is subsequently heated in the air or in an atmosphere containing an equivalent or higher amount of oxygen without contact with a heat source, the polymer substrate is sucked from both sides in the width direction during the temperature rise treatment. According to the present invention, tension is applied in both the longitudinal direction and the width direction of the substrate during the annealing treatment of the thin film formed on the long polymer substrate. In the following, embodiments of the present invention will be explained with reference to the drawings, but FIG. 1 shows one example of the present invention. Figure 2 shows an example. The difference from Figure 3, which shows a conventional example, is that a suction nozzle 7 is provided in the heated part. Figure 2 shows a cross section of the section A-A' in Figure 1. The polymer substrate 3 is subjected to tension in the width direction by the suction nozzle 7 while passing near the heater 5 consisting of a heat source 9 and a reflection plate 8. Also, various vacuum pumps can be used as the suction means 7. A CoCr layer with a thickness of 250 nm is provided on a polyimide substrate with a thickness of 10 μm and a diameter of 20 cm by vacuum evaporation. In order to oxidize the surface of the magnetic recording medium, an annealing treatment was carried out at an annealing temperature of 320° C. and 300 t, and a film running speed of 1 m/min. An attempt was made to reduce curl by applying tensile strength in the width direction of the substrate using the suction nozzle 7.As a preliminary experiment, the annealing temperature was determined using a thermocouple formed by vapor deposition on the polymer substrate surface on the heater side. The tensile strength in the width direction of the substrate due to the suction nozzle 7 was determined based on the results obtained by calculating the temperature relationship.In addition, the tensile strength in the substrate width direction due to the suction nozzle 7 was determined by preliminary experiments using a strain gauge on the polymer substrate 3.
Furthermore, the curl strength was evaluated by the amount of warpage when the thin film after the annealing treatment was cut into a circle with a diameter of 30 mrn, and the measurement results are shown in Figure 5. The oxidation state, as determined by Augier electron spectroscopy, was not changed by suction as long as the annealing temperature was the same. For the purpose of surface oxidation of a perpendicular magnetic recording medium in which a CoCr layer with a thickness of 300 nm was provided on a substrate by vacuum evaporation, annealing treatment was performed at an annealing temperature of 300 °C and 280 t, and a film running speed of 1 m/min. A similar effect was also obtained when CoCrNi was used instead of CoCr. Curling in the width direction of the substrate that occurs during processing can be reduced.

[Brief explanation of drawings]

Figure 1 is a front view showing an example of an annealing process in a thin film manufacturing method according to an embodiment of the present invention. Figure 4 is a front view showing a conventional example of an annealing process.
FIG. 5 is a graph showing the relationship between suction strength and curl strength in the method for manufacturing a thin film according to an embodiment of the present invention.Mode 1...Rotating method 2...Unwinding low/k 3・・・
・Polymer base maple on which a thin film is formed 4... Guide roller, 5... Heater for heating 6... Winding roller/k
7... Suction nozzle ＼ 8... Reflection maple 9...
Hot wind fan 11...Heating roller.

Claims (4)

[Claims] (1) After forming a thin film layer on a long polymer substrate directly or via an underlayer, the polymer substrate is heated in the atmosphere or in an atmosphere containing an equivalent or higher amount of oxygen without contacting a heat source. A thin film manufacturing method comprising: sucking the polymer substrate from both sides in its width direction during the temperature raising treatment. (2) The method for producing a thin film according to claim 1, wherein the thin film layer is made of a magnetic material for magnetic recording. (3) The method for producing a thin film according to claim 1 or 2, wherein the thin film layer contains Co, Cr, or Co, Cr, and Ni as main components. (4) Claim 1, 2 or 3, wherein the material of the polymer substrate is aromatic polyamide or polyimide.
Method of manufacturing the described thin film.