JPH0331787B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field This invention is directed to a sputtering device or
The present invention relates to a vacuum evaporation method used to form a deposited film using a vacuum evaporation apparatus. BACKGROUND ART Conventionally, the following method has been used to partially form a deposited film at required locations on a substrate surface. (1) Cover the necessary parts of the entire surface of the substrate with a resist, remove the unnecessary parts by etching, and then peel off the resist to expose the necessary parts. (2) Mask the non-evaporation surface of the substrate with a heat-resistant plate made of glass, alumina, metal, etc. and perform vapor deposition. Problems to be Solved by the Invention If the material deposited on the substrate is a material that can be etched, such as silicon, copper, or aluminum, the purpose can be achieved by the method of conventional technique (1) above.
For non-etchable ceramics such as silicon carbide, titanium carbide, and silicon nitride, or for materials that can be etched but where the underlying material is affected during etching, there are various deficiencies in the method. The method of conventional technology (2) is adopted. This problem will be explained below using a thin film type thermal head as an example. The heating element substrate of a thermal head is roughly divided into three types of thin films, each having a different function: a heating element layer, a conductive layer, and a protective film layer, which are laminated together by vapor deposition on an alumina substrate. First, the heating element layer is formed in the shape of strips at intervals of approximately 100μ on the longitudinal center surface of the long board.Next, this heating element is equipped with a conductor for connecting to an external drive circuit. The electrical conductors are formed in the direction perpendicular to the arrangement of the heating elements, and finally, the portions of the electrical conductors other than the external circuit connection portions are covered with a wear-resistant and corrosion-resistant protective film. Of these, the heating element layer and the conductive layer are made of materials that can be etched, so they are vapor-deposited on the entire surface and then partially formed using the conventional technique (1) above. However, the uppermost protective coating layer is In addition to the above characteristics, the material must also have heat resistance and insulation properties. Therefore, ceramic materials such as silicon carbide and titanium carbide are partially sputtered using the conventional technique (2) above. It is vapor-deposited. In this conventional technology (2), in order to prevent sputtering vapor from entering during sputtering, the mask plate must be attached closely to the substrate. (approximately 500℃)
When the substrate or mask plate undergoes thermal deformation, abnormal stress is generated in the facing area of the two, causing the copper,
Made of aluminum, gold, etc., several microns thick and 30 to 80 μm wide.
damage the electrical conductor and lead to disconnection. On the contrary,
When the directions of thermal deformation of the mask plate and the substrate are opposite to each other, spatter steam enters the gap between the two, which has the disadvantage of causing defects such as the connection portion being covered with a nonconducting film. was. Therefore, the present invention provides a flexible mask material that does not cause the mask and the substrate to come into contact with strong force or create a gap between them even if the substrate undergoes thermal deformation, on the easily damaged substrate surface. The object is to provide a vacuum deposition method which overcomes the drawbacks of the prior art by direct deposition. Means for Solving the Problem In order to solve this problem, the present invention provides for directly applying either or both of montmorillonite and zeolite fine powders containing aluminosilicate as a main component directly to the non-evaporated surface of the substrate. By using a rehydratable heat-resistant coating film formed by applying and drying a dispersion containing the water or other substances as a mask material,
This allows partial deposition of non-etchable deposition materials. Function The film-like mask material of the present invention has appropriate adhesion strength, so it can adhere to substrates having material surfaces such as copper, gold, tantalum, alumina, etc., and also has appropriate flexibility. have Therefore, even if the substrate undergoes thermal deformation, no gap is created between the substrate and the mask, and no force is generated that presses the substrate surface. Therefore, there is no damage to the substrate surface, and there is no chance of steam getting around. This alone is not sufficient to meet the requirements for a mask. The main conditions are as follows: (1) The mask must have a suitable adhesive strength without peeling off, disintegrating or scattering until the series of operations is completed. (2) In the case of a thermal head, it must be able to withstand high temperatures (400 to 500℃) and not cause cracks. (3) Do not generate harmful impurities (thermal decomposition products). (4) The coating film can be easily formed and peeled off without damaging the base. (5) Do not alter the quality of the substrate surface. The mask material of the present invention satisfies these conditions. Embodiment An embodiment of the present invention will be described in detail below. It can be said that the present invention lies entirely in how to find a material that satisfies the above conditions. After repeated tests and studies on coated mask materials that meet these conditions, representative examples of those that can be practically applied are shown in the table below in the form of dispersion ratios.

[Table] In this table, the mixing ratio of the dispersion medium has a large effect on the viscosity of the liquid. Therefore, it is necessary to determine the method of application and the properties of the powder. This table merely shows an example for understanding the properties of the dispersion. Next, the procedure for configuring the present invention will be explained using a thermal head as an example. The dispersion liquid is sufficiently mixed with a stirrer, adjusted to an appropriate viscosity, and applied to the mask portion of the substrate by means such as brush, spray, screen printing, roll coater, and dipping. The coating thickness is affected by the properties of the dispersion and the coating method, but it should be at least 1 μm thick in a dry state. If applied thickly over 200μ, cracks may occur due to uneven drying. In terms of drying speed after application, ease of handling, etc., a thickness of about 30μ to 150μ is desirable. Next is drying. Montmorillonite, kaolin, etc., which are the raw materials for the dispersion, contain water of crystallization within their powders, which cannot be completely removed at normal drying temperatures (200°C or lower). However, since the release temperature of this crystal water is approximately 600° C. for the former and approximately 450° C. for the latter, this effect can be avoided if the vapor deposition is performed at a lower temperature. However, montmorillonite has the property of retaining a large amount of water (approximately 10%) in addition to this crystallized water, and this water is not released unless it is heated to approximately 170°C or higher. Therefore, for dispersions containing montmorillonite, it is desirable to dry them in advance at a temperature of 170°C or higher in order to reduce the amount of moisture carried into the vapor deposition equipment. Unless the atmosphere is inert, it will oxidize the metal (copper) deposited on the base. Therefore, we attempted vapor deposition by drying at a temperature of 50°C. As a result, there is no reduction in the degree of vacuum during vapor deposition.
A normal deposited film could be formed. This is thought to be because the moisture in the mask material was completely removed when the substrate was heated (400°C to 500°C) before vapor deposition. Next is vapor deposition using a sputtering device.
It was carried out under the same conditions as before without any special operations. After the vapor deposition was completed, the substrate was immersed in water, and the mask material layer was rehydrated and peeled off. In this case, peeling can be easily performed using an ultrasonic cleaner. Partial deposition on the substrate is completed through the above operations. In addition, the dispersion liquid No. 1 in the above table has the characteristic that the mask layer can be peeled off without rehydration, but if care is not taken, the mask layer may peel off when the substrate is removed from the equipment. It has the problem of peeling off and contaminating the work space. Next, I will describe the main properties of raw materials that I learned during the testing and study process. All of the B powders listed in the table above can form a coating film on the substrate surface relatively easily, but in the dry state, the bonding strength of individual particles is weak and they disintegrate with just a slight impact. , it scatters in powder form and cannot be put to practical use alone. On the other hand, A
When the powder is dispersed in water, applied and dried, the bond between the particles is extremely strong. However, montmorillonite is composed of a fine colloidal substance, and when used alone, it may crack during drying (high shrinkage rate) depending on the type (differences in the proportion of impurities mixed in due to different production areas, differences in refining methods, etc.). (because of this) a coating film cannot be formed on some products. However, by mixing an appropriate amount of a substance with poor bonding strength, such as the B powder, it is possible to compensate for each other's shortcomings and make the material suitable as a mask material. If the particle size of Powder B mixed with Powder A is too large, it may damage the substrate during application or work, so it is preferable to have a smaller particle size, but if it is extremely small (0.05μ or less), it will cause Shrinkage is severe and cracks and peeling occur. In addition to powders for ceramics and ceramics listed in Table B above, powders that can be mixed with powder A to form coatings include:
Glass powder, refractory material powder, or water-insoluble inorganic substances such as calcium phosphate, barium sulfate, calcium sulfate, etc. may also be used. There are natural minerals that already contain a portion of powder A, and the use of such powder is also included in the present invention. In addition to the above-mentioned inorganic materials, for the purpose of improving the coating properties of the dispersion, for example, organic substances with low boiling points (surfactants, viscosity agents), or substances such as magnesium oxide for viscosity adjustment may be mixed as auxiliaries. It is also within the scope of the present invention to do so. Although the thermal head has been described above as an example, the present invention can also be applied to integrated circuits, tools, mechanical parts, etc. in which ceramic films are partially deposited. Effects of the Invention In the present invention, a mask material made of zeolite or montmorillonite has a suitable strength and is tightly adhered to a substrate by the adhesive force of the mask material itself. Partial deposition can be performed without damaging the substrate surface when attaching the material, and without causing deposition gas to enter the gap between the mask and the substrate. The final step of this vapor deposition, the peeling off of the mask material, is also
This can be done easily by rehydration, so the substrate will not be damaged. Furthermore, since the mask material is attached by a coating method, it is easy to automate the manufacturing process. According to the present invention, the occurrence of wire breakage or warping defects has been greatly reduced. The results are shown below.

[Table] Another effect is that the thickness of the evaporation mask is much thinner than that of the conventional method (from 2 mm to approximately 100μ), so the evaporation time to form a deposited film of the same thickness is greatly shortened. (approximately 35%) and improved equipment capacity. Furthermore, since a holding metal fitting to support the mask is no longer necessary, the number of pinhole defects in the substrate, which is caused by the vapor deposits adhering to the surface of the metal fitting peeling off and scattering during vapor deposition, has been greatly reduced.

Claims (1)

[Claims] 1. A solution prepared by dispersing a powder containing zeolite or montmorillonite as a main substance alone or a mixture with other substances containing at least one or both of the above powders in water is applied onto the substrate surface and dried. The resulting coating surface is used as a mask during vapor deposition.
A vacuum deposition method characterized by partially forming a deposited film on a substrate.