JPH0371509B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method for forming a ZrO ₂ (zirconium oxide) transparent film of arbitrary shape.

(Description of Prior Art) It has been known that ZrO ₂ transparent films have electrical insulation properties. However, at present, this ZrO ₂ transparent film is not actively used to form, for example, thermal heads, multilayer wiring, or other electrical components. The reason seems to be that no effective method for forming ZrO ₂ transparent films of arbitrary shapes has been found.

For example, there are two conventional methods for forming a ZrO ₂ transparent film in an arbitrary shape.
The first method uses a Zr-O target and Ar gas or a mixed gas of Ar and O ₂ (however, O ₂ is
% or less) to sputter the alumina substrate,
In this method, a ZrO ₂ transparent film is formed on an arbitrary substrate such as a silicon wafer, and then the ZrO ₂ transparent film is etched using a photolithography process to obtain a predetermined shape. However, this ZrO ₂ transparent film and Ta ₂ O ₅ film cannot be easily etched due to their film properties, so they have the drawback of being extremely difficult to pattern.

Another method is to directly pattern a ZrO ₂ transparent film on an arbitrary substrate using a metal mask, but this method does not allow accurate patterning of the ZrO ₂ transparent film. In particular, it was extremely difficult to form fine patterns.

In any case, with the method described above, it was not possible to form a fine, clean, and sharp ZrO ₂ transparent film pattern with good reproducibility.

(Summary of the Invention) In view of the drawbacks of the conventional methods described above, the inventors conducted _many experiments and found that _Zr-
The part of the N (zirconium nitride) film covered with the Au film is more easily treated than the part not covered with the Au film by heat treatment in an oxidizing atmosphere.
We discovered a phenomenon in which _ZrO2 transforms into a transparent film.
On the other hand, it has been known for a long time that Au films and Zr-N films can be microfabricated more easily than ZrO ₂ films. Therefore, by micromachining the Au film and/or Zr-N film in advance and utilizing these micropatterns or microstructures, a ZrO ₂ transparent film with a micropattern and/or microstructure is formed, and this ZrO ₂ It has been found that transparent films can be effectively used in, for example, thermal heads, multilayer wiring, other electrical elements and components, and other non-electrical applications.

Purpose of the Invention Therefore, the purpose of the present invention is to create a micropattern, a fine structure, or a combination thereof.
The object of the present invention is to provide a method for simply and easily forming a ZrO ₂ transparent film with good reproducibility.

Structure of the Invention In order to achieve this object, in the present invention, the part of the Zr-N film that is covered with the Au film is removed by heat treatment in an oxidizing atmosphere. The Au film and Zr-N film are more easily transformed into a ZrO ₂ transparent film than the ZrO ₂ film.
This takes advantage of the fact that it can be more easily microfabricated than films.

Therefore, the method for forming a ZrO ₂ transparent film of the present invention includes the steps of providing a Zr-N film with a thickness of 1 μm or less on the entire surface or a part of the underlayer, and
This process involves providing an Au film with a thickness of 2 μm or less on the entire surface or part of the N film, and heat treatment at a temperature of 200°C or more for 5 hours or more in an oxidizing atmosphere.
The method is characterized by including a heat treatment step for converting the Zr-N film located under the Au film into a ZrO ₂ transparent film.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, the shape, arrangement, and dimensional relationship of each component are merely shown schematically to the extent that the structure of the present invention can be understood. Further, although the embodiments described below are explained under suitable conditions within the scope of the present invention, these are merely illustrative.
It should be understood that the invention is not limited to this example.

First, a first embodiment of the present invention will be described with reference to FIGS. 1A to 1C and FIGS. 2A and 2B.

In this embodiment, first, as shown in FIG. 1A,
A glazed alumina substrate is used as the base layer 1, and a ZrN film 2 is provided as a Zr-N film on the entire upper surface 1a of this substrate 1 by any suitable method, for example, a physical vapor deposition method such as reactive sputtering. . As an example, the specific resistance of this ZrN film 2 is
The resistance should be 10000μΩcm and the thickness should be 500〓~1μm.

Next, an Au film 3 is provided on a portion of the ZrN film 2 to a thickness of 1 to 2 μm by any suitable method, for example vapor deposition.

Next, at least these films 2 and 3 provided on the substrate 1 are heat-treated in an oxidizing atmosphere at a temperature of about 200°C or higher, preferably at a temperature of 200 to 400°C, preferably for 5 to 10 hours. As the heat treatment time elapses, the ZrN film 2 is sequentially oxidized from the surface side on which the Au film 3 is attached to the substrate 1 side, forming a ZrO ₂ transparent film 4 (4a, 4b).
FIG. 1B shows the state of change during the course of the process, and FIG. 1C shows the state after 5 to 10 hours have passed.
In this way, the reason why the ZrN film portion covered with the Au film changes into a ZrO ₂ film is that it promotes the oxidation of the ZrN film, that is, Au acts as a catalyst for the oxidation of ZrN. Guessed.

As is clear from these figures, the portion 2a of the ZrN film 2 below the Au film 3 extends over its entire thickness.
However, in the part _{2b of the ZrN film 2 that is not covered with the Au film 3, only a very shallow part of the surface is covered with the ZrO 2 transparent} film 4b (in the figure,
For clarity, the thickness is emphasized and shown as a uniform thickness, but in reality it can be interpreted as island-like regions with different thicknesses. It can be considered that there has been no change.

According to experiments, as shown in Figure 2A, this
When the ZrN film 2 that is not coated with the Au film is heat-treated under the same conditions as described above, as shown in FIG. 1000 to transform into a _ZrO2 transparent film over its entire thickness.
It was found that heat treatment for a longer period of time was required.

In addition, it has been found that in order to promote the phenomenon of transformation into a ZrO ₂ transparent film, the heat treatment temperature may be increased to a high temperature and/or the heat treatment time may be increased for a long time.

Incidentally, the Au film 3 can be simply and easily microfabricated by a photolithography process. Therefore, in the method described above, after forming the ZrN film 2 on the substrate 1, the Au film 3 is provided on the ZrN film 2, for example, by vapor deposition, and then the Au film 3 is
Using a photolithography process, any shape, arrangement, and size of 1 to 10 μm that conforms to or nearly conforms to the design conditions of the ZrO ₂ transparent film 4a to be formed.
By processing the ZrO ₂ into a fine pattern of 1 to 10 μm, which is the same or almost the same as the pattern of this Au film, by processing it into a fine pattern of 1 to 10 μm and then performing a prescribed heat treatment at a temperature of 200°C or more for 5 hours or more. membrane 4
It is possible to form a.

In this case, when viewed from the ZrO ₂ transparent film 4, Au
There is an advantage that a ZrN mask can be made without etching the film 3 as a negative mask.

Further, since the ZrN film 2 is divided into a ZrN portion and a ZrO ₂ portion, although there is a volume change due to a structural change, the film surface has almost no unevenness and can be considered to be a substantially flat surface.

Furthermore, by removing the separated ZrN film 2b by a normal etching process, only the ZrO ₂ transparent film 4a having a fine pattern of arbitrary shape, arrangement, and size can be formed on the base layer 1.

Next, a method for forming a fine pattern of ZrO ₂ transparent film on the underlayer will be explained with reference to FIGS. 3A and B to FIGS. 8A and B. In addition, in FIGS. 3 to 7, A is a dashed-dotted line in the plan view B.
−, −, −, −
, - are sectional views taken along lines 1 and 2, respectively.

First, as shown in FIG. 3A and B, the base layer 1 is
1, a glazed alumina substrate is prepared.

Next, as shown in FIGS. 4A and 4B, ZrN12 is formed as a Zr-N film on the upper surface 11a of this substrate 11.
was deposited to a thickness of 3000 mm by reactive sputtering, and then an Au film of 1 to 10% was deposited on the entire surface of this ZrN film 12.
Deposit to a thickness of 2 μm.

Next, as shown in FIGS. 5A and 5B, this Au film 13 is etched into, for example, an E-shaped fine pattern 13a when viewed from above using a photolithography process.

In this case, the above-described entire surface vapor deposition of the Au film 13,
Instead of using a photolithography process and etching, a metal mask can be used to directly etch Au.
It is also possible to form a fine pattern of the film 13a.

Next, the structure obtained in the process shown in Fig. 5 is
in an oxidizing atmosphere, e.g. air, at a temperature of 7°C.
Perform heat treatment for a time. By this heat treatment, as shown in FIGS. 6A and 6B, the lower side of the Au film 13a is
The part 12a of the ZrN film is changed to a ZrO ₂ transparent film 14a, and the part 12 of the ZrN film is not covered with the Au film.
b remains virtually unchanged.

Next, as shown in FIGS. 7A and 7B, the finely patterned Au film 13a is removed by ordinary etching or the like. At this time, the same pattern as the Au film,
A ZrO ₂ transparent film 14a having an E-shaped fine pattern is obtained. The ZrO ₂ transparent film 14a at this stage can be applied to the manufacture of electrical elements, electrical parts, and other products.

Furthermore, as shown in FIGS. 8A and 8B, the ZrN film 12b is removed by a normal method to form a layer on the substrate 11.
It is also possible to leave only the ZrO ₂ transparent film 14a. ZrO ₂ transparent film 14a at this stage
It can also be applied to the manufacture of electrical elements, electrical parts, and other things.

Next, a second embodiment of the present invention will be described with reference to FIGS. 9A to 9F.

In this example, the ZrN film was microfabricated in advance.
This is a method of forming a pattern of ZrO ₂ transparent film.

First, as shown in FIG. 9A, a glazed alumina substrate is prepared as the base layer 21, and then,
As shown in FIG. 9B, a ZrN film 22 is formed as a Zr-N film to a uniform thickness on the upper surface 21a of this substrate 21 by any suitable method.

Next, this ZrN film 22 is etched using a photolithography process to form a fine pattern 22a of the ZrN film as shown in FIG. 9C. Since this ZrN can be easily microfabricated, this micropattern is formed to have the same or almost the same shape, arrangement, and dimensions as the micropattern of the ZrO ₂ transparent film to be formed.

Next, as shown in FIG. 9D, an Au film 23 is formed on the entire surface of the substrate 21 including the fine pattern 22a of the ZrN film.
in any suitable manner.

After that, at least the pattern 22 of this ZrN film is
a and the Au film 23, but in this case, for example, the entire structure obtained in FIG.
9E in an oxidizing atmosphere, preferably for 5 to 10 minutes.
The pattern 22a of the ZrN film is changed to a fine pattern 24 of the ZrO ₂ transparent film.

Next, if necessary, the Au film 23 may be etched using a normal method so that its surface is in the same surface position as the fine pattern 24 of the Zr-O transparent film, or as shown in FIG. 9F. , the Au layer 23 may be completely removed.

Next, a case where the present invention is applied to a method for manufacturing a thermal head and a manufacturing method for multilayer wiring will be explained.

FIG. 10A is a partial plan view showing the main parts of the thermal head with the protective film removed, FIG. X in Figure 10A, respectively, when manufactured using the method according to the invention.
- A sectional view taken along the X-ray, in this case showing a state with a protective film attached.

In these figures, 31a and 31b are Au,
Electrodes made of Al or Cr, etc., 32 a ZrN heating element, 33 a glazed alumina substrate as a base layer, 34
is a protective film such as Al ₂ O ₃ , SiO ₂ , or SiC,
35 is a ZrO ₂ transparent film.

As is clear from a comparison with FIGS. 10B and 10C, it is difficult to make the surface of the protective film smooth in the thermal head manufactured by the conventional method, but when manufactured using the method of the present invention, is the heating element 32
In between, the ZrO ₂ transparent film 35 can be made to have the same thickness as the heating zone, and the protective film 3 provided above
4 can also be made smooth, which provides the advantage that wear of the protective film due to contact with the platen is significantly less than in the conventional case.

Furthermore, since the thermal conductivity of the protective film 34 is higher than that of the ZrO ₂ film 35, the structure shown in FIG. The advantage is that it is much better than the conventional method.

FIGS. 11A to 11E are diagrams for explaining an example in which the present invention is applied to the manufacture of multilayer wiring.

As shown in FIG. 11A, Zr--
After forming a ZrN film 42 as an N film and then an Au film 43 on at least the entire surface of this ZrN film 42 by any suitable method, a heating element to be formed is formed in an oxidizing atmosphere at an appropriate temperature. The ZrN film 4 is heated once for an appropriate time depending on the thickness of the ZrN film 4.
2 from the Au film side by a predetermined thickness ZrO ₂ transparent film 44
Convert it to

Next, the Au film 43 is etched by any suitable method to form a pattern 43 of the Au film corresponding to, for example, a pattern constituting a striped heating element.
a, and then heat-treated again in the same manner as described above to remove the ZrN on the lower side of the Au film pattern 43a.
The film 42 is completely transformed into a ZrO ₂ transparent film. In this way, as shown in FIG. 11B, a ZrO ₂ film 44 with a fine structure is obtained, and a pattern 43 of the Au film is obtained.
The part of the ZrN film that deviates from a is ZrN film pattern 4.
2a, which can constitute a heating element.

Next, after removing this Au film pattern 43a by a normal method, for example, a striped conductive layer made of Al, Au or any other suitable material is formed in a direction perpendicular to this striped heating element 42a. It is formed as a wiring 45. FIG. 11C shows this state in plan.

In addition, the cross-sectional view taken along the Y-Y line and the Z-Z line in FIG. 11C in this state is shown in the first section.
These are shown in Figure 1 D and E, respectively.

If multilayer wiring is manufactured in this way, the first layer wiring pattern (in this case, the heating element 42a) can be made only by heat treatment, without forming interlayer insulators by sputtering or vapor deposition. Furthermore, since the surface of the ZrO ₂ film is smooth, the wiring 45
The advantage of this method is that the yield when forming the wafer is significantly improved compared to the conventional method.

In each of the above-mentioned examples, the reason why the thickness of the ZrN film was set to 1 μm at the maximum was due to consideration of ease of patterning, and the reason why the film thickness of the Au film was set to 2 μm at the maximum was because of the antioxidant film. This is for economical reasons: to prevent this from happening, and because gold is expensive, we want to use as little amount as possible.
In addition, to determine whether the ZrN film has changed from a ZrO ₂ film, check with the naked eye whether the ZrN film has become transparent after heat treatment, and if the electrical resistance has become large enough to be considered an insulator. I measured and confirmed this.

(Description of Modifications) It is clear that the present invention is not limited to the embodiments described above.

For example, the underlayer may be a substrate other than the glazed alumina substrate, such as a silicon wafer, a ceramic substrate, or any other suitable material, or a film, layer, or other material.

In addition, Zr-
The Au layer provided on the top of the ZrN film as the N film is ZrN.
It is not necessarily necessary to provide it on the entire surface of the membrane, but it can also be provided on a portion of it depending on the design.

Furthermore, the method of forming each film, the etching method, or other techniques can be carried out using commonly used techniques. Furthermore, it is clear that the thicknesses of these films can be selected at appropriate values depending on the design other than those described in the above-mentioned embodiments.

Furthermore, the temperature and time during heat treatment are at least 200°C for 5 hours, but may be higher or for a longer time.
An appropriate value can be selected depending on the thickness of the -N film and the Au film, the oxidizing atmosphere, the thickness of the ZrO ₂ film to be formed, and other conditions.

Further, as the oxidizing atmosphere during the heat treatment, oxygen (O ₂ ), ozone (O ₃ ), or other atmosphere other than the atmosphere can be used.

(Effects of the Invention) As is clear from the above explanation, according to the method for manufacturing a ZrO ₂ transparent film according to the present invention, Zr-N
The part of the film covered with the Au film is more easily transformed into a ZrO ₂ transparent film than the part not covered with the Au film by heat treatment in an oxidizing atmosphere.
Moreover, since this method takes advantage of the fact that Au films and Zr-N films can be microfabricated more easily than ZrO ₂ films, there is no need to microfabricate the ZrO ₂ film itself.
It is possible to microfabricate the Au film or Zr-N film and then perform heat treatment to change the Zr-N film directly under the Au film into a ZrO ₂ film, forming a ZrO ₂ film with a micro pattern or micro structure. . Therefore, it is possible to easily form a ZrO ₂ transparent film with a fine pattern or fine structure that is finer than before, and has a neat and sharp shape with good reproducibility.

The method for forming a ZrO ₂ transparent film according to the present invention is suitable for application to various electrical devices, elements, parts, etc., as well as other items.

[Brief explanation of drawings]

1A to 2C and 2A and 2B are schematic cross-sectional views for explaining the first embodiment of the present invention;
Figures A and B to Figure 8A and B are schematic plan views showing states at main process steps to explain the method of forming a finely patterned Zr-O film using the first embodiment of the present invention. and schematic cross-sectional views, FIG. 9A~
F is a schematic sectional view showing the state at the main process steps for explaining the second embodiment of the present invention, and FIGS. , A is a schematic plan view,
and B are schematic cross-sectional views of the case manufactured by the conventional method, and C are schematic cross-sectional views of the case manufactured by applying the present invention, and FIG. 11 is a main process for explaining the case of applying the present invention to the manufacture of multilayer wiring. In the drawings showing the state at each stage, A, B, D, and E are schematic cross-sectional views, and C is a schematic plan view. 1, 11, 21, 33, 41... base layer, 1
a, 11a, 21a...upper surface (of base layer),
2, 12, 22, 42...ZrN film, 2a, 12a
... Part of the ZrN film (underneath the Au film), 2b, 1
2b...ZrN film part (without Au film), 22a
...Fine pattern (of Zr-N film), 3, 13,
23, 43...Au film, 3a, 13a, 23a...
...(Au film) fine pattern, 4, 14, 35,
44...ZrO ₂ transparent film, 4a, 14a... (underneath the Au film) ZrO ₂ transparent film part (or fine pattern of ZrO ₂ transparent film), 4b, 14b... (without Au film) ZrO ₂ Transparent membrane parts, 4c, 4d... island-like
ZrO ₂ transparent film, 31a, 31b... electrode, 32...
... Zr-N heating element, 24 ... Fine pattern of ZrO ₂ transparent film, 34 ... Protective film, 43a ... Au film pattern, 45 ... Wiring.

Claims (1)

[Claims] 1. In forming a ZrO ₂ transparent film on the base layer, a step of providing a Zr-N film with a thickness of 1 μm or less on the entire surface or a part of the base layer; and the Zr-N film. A step of providing an Au film with a thickness of 2 μm or less on the entire surface or a part of the Zr-N film located below the Au film, and heat treatment for 5 hours or more at a temperature of 200°C or more in an oxidizing atmosphere. A method for forming a ZrO ₂ transparent film, comprising a heat treatment step for converting the film into a ZrO ₂ transparent film.