JP2000156381A - Forming method of electric wiring and electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forming method of an electric wiring capable of accurately forming a specified electric wiring on the side surface of a base member having a solid shape and on a base member having unevenness. SOLUTION: In this forming method of an electric wiring, (a) a first process forming a metal thin film 300 which can be anodized, (b) a second process which forms a notch 351 on the metal thin film 300 and divides it into a part 330 to be made an electric wiring and a part 331 to be eliminated, (c) a third process which anodizes the part 331 to be eliminated and changes it to a porous anodic oxidation film 301, and (d) a fourth process which selectively eliminates the part 331 to be eliminated are performed in this order, and an electric wiring is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an electric wiring suitably used for manufacturing electronic components such as a semiconductor device, a liquid crystal device, and a crystal unit, and an electronic component manufactured by such a method.

[0002]

2. Description of the Related Art The formation of electric wiring in electronic parts is mainly performed by using an etching technique (wet and dry) or a lift-off technique. These techniques are disclosed, for example, on page 41 of Introduction to Ultrafine Processing (Ohm Co., Ltd., Shizujiro Yoshikawa et al.).

[0003] In the case of the etching technique, a metal thin film is formed on a base material, and a region to be an electrode portion of the metal thin film is selectively covered with a photoresist by a photolithography technique. Thereafter, portions of the conductive thin film that are not covered with the photoresist are selectively removed by etching to form electric wiring.

In the case of the lift-off technique, a pattern of a photoresist is first formed on a substrate, and then a metal thin film is formed on the entire surface of the substrate. Thereafter, the electrical wiring is formed by removing the portion of the metal thin film to be removed together with the photoresist.

[0005]

However, when electric wiring is formed on the side surface of a substrate having a three-dimensional shape,
It is difficult to apply photoresist uniformly on the side of a substrate having a three-dimensional shape, and it is not possible to expose the applied photoresist well. However, it is not easy.

In the case where electric wiring is formed on a substrate having irregularities, it is necessary to apply a photoresist on the substrate having irregularities. However, there is a problem that it is not easy to form an electric wiring having a desired shape.

Accordingly, an object of the present invention is to solve the above-mentioned problems, and to accurately form a predetermined electric wiring on a side surface of a three-dimensional substrate or on a substrate having irregularities. An object of the present invention is to provide a method for forming an electric wiring that can be performed.

Another object of the present invention is to provide a high quality electronic component at a low price by using such a method of forming an electric wiring.

[0009]

According to a first aspect of the present invention, there is provided a method for forming an electric wiring, comprising: (a) a first step of forming an anodically oxidizable metal thin film on a base material; A second step of providing a cutout to divide into a portion to be an electric wiring and a portion to be removed, and (c) anodizing the portion to be removed to change it to a porous anodic oxide film A third step and (d) a fourth step of selectively removing the portion to be removed are provided in this order.

For this reason, in the fourth step, by selecting an appropriate removing solution such as nitric acid (hereinafter referred to as an etching solution), a porous anodic oxide film can be formed while leaving a portion to be used for electric wiring. Only the portion to be removed can be easily removed.

The step of forming a metal thin film in the first step and the step of forming a notch in the second step can be easily applied to a side surface of a substrate having a three-dimensional shape or a substrate having irregularities. Therefore, the predetermined electric wiring can be accurately formed even in such a complicated shape.

Here, the notch is provided to prevent conduction between a portion to be an electric wiring and a portion to be removed. From this point of view, the width of the notch is preferably as wide as possible, but if it is too wide, it becomes difficult to form fine electrode wiring.

As the anodically oxidizable metal thin film formed in the first step, a thin film made of an anodizable metal such as aluminum, aluminum alloy, titanium, and tantalum can be used. (Claim 2).

The reason is that aluminum is inexpensive,
Also, it is because it has the highest electric conductivity among the anodizable metals. When an aluminum alloy is used, an aluminum alloy containing a trace amount of metal (for example, 0.1% by weight of copper) is preferable from the viewpoint of the etching property of the anodic oxide film.

In the second step, an energy converging beam machining method or an electric discharge machining method can be used. Further, when the metal thin film is very thin like a monoatomic layer, an atomic force microscope or a tunnel microscope is used. Although a method of removing atoms using the tip of a sensing lever used in the method can be used, it is preferable to use a processing method using an energy converging beam from the viewpoint that the thickness of the metal thin film is practically 1000 Å or more. 3).

As a processing method using an energy focused beam, a laser beam processing method, a focused ion beam processing method,
Ultrasonic ultrasonic beam processing can be used, but laser processing is preferable from the viewpoint of miniaturization of the width of the electric wiring film and the simplicity of the manufacturing apparatus (claim 4).

According to a fifth aspect of the present invention, there is provided a method for forming an electric wiring according to the first aspect, wherein the third step is performed using a sulfuric acid solution. Thereby, the anodic oxide film can be made porous.

According to a sixth aspect of the present invention, in the method for forming an electric wiring according to the first aspect, the electric wiring is formed on a side surface of a base material having a three-dimensional shape. Therefore, electric wiring can be easily formed on the side surface of the base material.

According to a seventh aspect of the present invention, in the method for forming an electric wiring according to the sixth aspect, the base having the three-dimensional shape is a base of a piezoelectric vibrator. Therefore, it is possible to easily manufacture the piezoelectric vibrator having the side electrodes.

According to an eighth aspect of the present invention, in the method for forming an electric wiring according to the first aspect, the electric wiring is formed on a substrate having irregularities.
For this reason, for example, in electrical connection between a plurality of elements,
The connection can be easily performed without the influence of the step between them. Further, since a resist coating step and a photolithography step can be eliminated, the steps can be rationalized.

According to a ninth aspect of the present invention, in the method for forming an electrical wiring according to the eighth aspect, the substrate having the irregularities is a substrate of a liquid crystal device or a semiconductor device. . Therefore, a multi-chip module in which a plurality of elements are arranged on one base material can be easily manufactured.

An electronic component according to claim 10 is the electronic component according to claims 1 to 9
The method is characterized by being manufactured using the method for forming an electric wiring according to any one of the above. Therefore, the electronic component can be manufactured at low cost and with high quality.

The electric wiring is mainly used for exchanging electric signals. However, the electric wiring can be applied to other shapes such as a reflection pattern, a thickness adjustment pattern, and a groove pattern.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on each embodiment.

(Embodiment 1) FIG. 1 shows an electronic component (a quartz oscillator 1) manufactured by using the method for forming an electric wiring of Embodiment 1.
FIG. This crystal resonator 100 is used as a crystal sensor, has a three-dimensional shape (specifically, a tuning fork shape), and includes two tuning fork arms 110 protruding from a base. Each tuning fork arm 1
The electric wiring 201 is formed on the upper surface, the lower surface, and the side surface of the device 10. An electrode pad 200 for exchanging electric signals with an external electric circuit is also formed on the base.

FIG. 2 is a process chart showing a method of forming the electric wiring 201 of the crystal unit 100 of FIG. This process diagram is based on a cross-sectional view of one tuning fork arm of the two tuning fork arms 110 in FIG. Hereinafter, a method for forming an electric wiring according to the second embodiment will be described with reference to FIG.

The method for forming the electric wiring of the first embodiment is as follows:
A first step of forming an anodically oxidizable metal thin film on a base material; and (b) providing a notch in the metal thin film to divide the metal thin film into a part to be an electric wiring and a part to be removed. (C) a third step of anodizing the part to be removed to change it to a porous anodic oxide film, and (d) a fourth step of selectively removing the part to be removed. Steps in this order.

(First Step) First, as shown in FIG. 2A, an anodically oxidizable metal thin film 300 serving as an electric wiring material is formed on the entire surface of the tuning fork arm 110. Metal thin film 300
Used was aluminum having a purity of 99.99%. The thickness is about 3000 angstroms. As a film forming method, a vacuum evaporation method or a sputtering method is used.

(Second Step) Next, as shown in FIG. 2B, the metal thin film 300 is irradiated with an energy converging beam 500 to form a notch 351 in the metal thin film 300 to form an electric wiring 201. A part 330 to be removed and a part 331 to be removed in a later step are divided.

As the energy converging beam 500, Y
A laser beam emitted from an AG laser is used. The wavelength is 532 nanometers, the energy is about 1 microjoule, and the beam diameter is about 10 micrometers. In FIG. 2B, the energy converging beam 5
Although 00 is emitted from the horizontal direction, it may be emitted from an oblique direction at an angle.

(Third Step) Thereafter, as shown in FIG. 2C, the portion 331 to be removed is anodized to change into a porous anodic oxide film. The method of anodizing aluminum is described, for example, from page 111 of Aluminum Surface Treatment Handbook (published by Light Metal Publishing, Light Metal Products Association). As an anodizing solution (not shown), for example, a 10% by weight sulfuric acid solution is used. The manufacturing conditions at that time include, for example, a power supply (not shown).
Is 60 V and the oxidation time is 2 minutes. The liquid temperature is 24 degrees Celsius. As a result, the portion 331 to be removed can be the anodic oxide film 301.

(Fourth Step) Thereafter, the crystal unit 100
When the whole is put in nitric acid, which is an etching solution, FIG.
As shown in (d), since the portion 331 to be removed is a porous type anodic oxide film 301, it is dissolved and removed in nitric acid.

On the other hand, the portion 330 to be the electrode wiring (that is, the electric wiring 201) is still aluminum, and is not removed because it does not dissolve in nitric acid. As a result, the electric wiring 201 as shown in FIG. 1 is formed.

According to the method of forming the electrode wiring of the first embodiment,
Since the method does not include the application of a photoresist and the subsequent exposure step, electric wiring can be easily formed on the side surface of the tuning fork portion of the crystal unit. Further, according to the electrode wiring forming method of the first embodiment, since no exposure mask is used, the electric wiring 201 can be freely formed only by changing the scanning pattern of the energy converging beam 500.

In the first embodiment, the method for forming the electric wiring 201 was described with reference to the quartz crystal sensor 100. However, the method for forming the electric wiring according to the present invention includes a pressure sensor using silicon, an acceleration sensor, and a silicon micromachining applied element. And so on.

(Embodiment 2) FIG. 3 is a perspective view of another electronic component manufactured by using the method for forming an electric wiring of Embodiment 2 and shows a multi-chip module including two semiconductor elements. . In the present electronic component, semiconductor elements 502 and 503 are fixed on a base material 501 serving as a base with an adhesive or the like, and electric wires 51 connecting the semiconductor elements 502 and 503 are provided.
0 is formed. In addition, only one electric wiring is shown to simplify the drawing.

The semiconductor elements 502 and 503 are, for example, 0.5
It has a thickness of about millimeters. The electric wiring 510 is formed after the semiconductor elements 502 and 503 are fixed and adhered to the base material 501. As a result, when forming the electric wiring 510, the present multi-chip module becomes one substrate having irregularities.

The manufacturing method (not shown) of the second embodiment differs from the manufacturing method of the first embodiment in the following two points. That is, first, since only one side of the substrate 501 is used,
FIG. 2A shows that the metal thin film 300 serving as the base of the electrical wiring only needs to be formed on one surface above the base material 501. Next, the laser irradiation shown in FIG. Direction).

Except for these two points, the step of anodizing the porous mold shown in FIG. 2C and the removing step of FIG. 2D are the same.

[Brief description of the drawings]

FIG. 1 is a perspective view of an electronic component according to a first embodiment.

FIG. 2 is a process chart showing a method for forming an electric wiring of Example 1.

FIG. 3 is a perspective view of an electronic component according to a second embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 crystal sensor 110 tuning fork arm 200 electrode pad 201 electric wiring 300 metal thin film 301 anodic oxide film 330 part to be made electric wiring 331 part to be removed 351 notch 500 energy converging beam 501 base material 502, 503 semiconductor element 510 electric wiring

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H090 JA05 JB04 LA01 2H092 GA60 HA06 MA18 MA19 MA24 NA27 PA01 5F033 HH08 PP15 PP19 QQ09 QQ19 QQ53 QQ68 QQ89 VV13 5J108 MM14

Claims (10)

[Claims] 1. A first step of forming a metal thin film that can be anodized on a base material, and (b) providing a cutout in the metal thin film to remove a portion to be an electric wiring. (C) a third step of anodizing the part to be removed to change it to a porous anodic oxide film, and (d) removing the part to be removed. And a fourth step of selectively removing in this order. 2. The method according to claim 1, wherein the metal thin film formed in the first step is made of aluminum or an aluminum alloy. 3. The method for forming an electric wiring according to claim 1, wherein the second step is performed by using a processing method using an energy converging beam. 4. The method for forming an electric wiring according to claim 3, wherein the processing method using the energy converging beam is a laser processing method. 5. The method for forming an electric wiring according to claim 1, wherein the third step is performed using a sulfuric acid solution. 6. The method for forming an electric wiring according to claim 1, wherein said electric wiring is formed on a side surface of a substrate having a three-dimensional shape. 7. The method for forming an electric wiring according to claim 6, wherein the base material having the three-dimensional shape is a base material of a piezoelectric vibrator. 8. The method for forming an electric wiring according to claim 1, wherein the electric wiring is formed on a substrate having irregularities. 9. The method for forming an electric wiring according to claim 8, wherein the substrate having irregularities is a substrate of a liquid crystal device or a semiconductor device. 10. An electronic component manufactured by using the method for forming an electric wiring according to claim 1.