JPH07321446A - Circuit pattern forming method - Google Patents

Abstract

PURPOSE:To provide a formation method which can form a circuit pattern with an improved performance such as insulation property with a simple and efficient process and can cope with a three-dimensional substrate. CONSTITUTION:A target 2 where a slit hole 3 corresponding to a circuit pattern shape is provided is brought closer to the surface of a substrate 1, at the same time nearly uniform plasma is generated on the surface of the target 2 at the opposite side of the substrate 1, and the side surface of the slit hole 3 of the target 2 is sputtered.

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 a circuit pattern.

[0002]

2. Description of the Related Art Conventionally, as a method of forming a circuit pattern on the surface of a substrate, generally two types of methods described below have been often performed. These methods are excellent in that a photo tool corresponding to the resist pattern shape is prepared and the same circuit pattern can be mass-produced by using this photo tool.

The first method is to form a metal film to be a circuit pattern on the entire surface of the substrate, form a resist film in a pattern shape on the metal film, and perform etching treatment to remove unnecessary portions of metal. This is a method of removing the film. However, in this method, since the metal film once formed on the substrate surface is removed by etching, the material is wasted.
For this reason, it is difficult to use an expensive metal film such as gold, and it costs a considerable amount to recover it.

As a second method to improve this point, after treating the substrate surface so as to have plating activity, a resist film having plating resistance is formed on the substrate surface in the reverse pattern shape, and the substrate surface is formed. There is a method of forming a metal film in a pattern to form a circuit pattern.

[0005]

However, in the above-mentioned typical two types of conventional examples, the steps of forming a uniform resist film, exposing and developing it in order to form a pattern of the resist film. However, there is a problem that the process becomes complicated. In addition, an etching solution, a plating solution, a resist, or the like may remain on the surface of the substrate on which the circuit pattern is not formed, which may affect the insulating property or the circuit characteristics. There is also a problem that it is difficult to form a circuit pattern on the surface of a three-dimensional substrate.

The present invention has been made to solve the above problems, and an object thereof is to form a circuit pattern having a good performance such as insulation in a simple and efficient process, and to obtain a three-dimensional structure. It is an object of the present invention to provide a method for forming a circuit pattern that can be applied to a shaped substrate.

[0007]

According to a first aspect of the invention for solving the above-mentioned problems, a target having slit holes corresponding to a circuit pattern shape is brought close to a surface of a substrate, and a target surface opposite to the substrate is provided. It is characterized in that a substantially uniform plasma is generated at the target and the side surface of the slit of the target is sputtered.

According to a second aspect of the present invention, a target having slit holes corresponding to the circuit pattern shape is brought close to the surface of the substrate, and at the same time, a substantially uniform plasma is generated on the target surface opposite to the substrate to generate a target. It is characterized in that a circuit pattern made of a plating film is formed on the circuit pattern formed by sputtering the side surface of the slit hole.

According to a third aspect of the present invention, a target having slit holes corresponding to the circuit pattern shape is brought close to the surface of the substrate, and at the same time, a substantially uniform plasma is generated on the target surface opposite to the substrate, and the target In the method of forming a circuit pattern in which the side surface of the slit hole is sputtered, sputtering is performed on the same substrate a plurality of times by sequentially using a plurality of or the same target, and the circuit pattern is formed by stacking on the same substrate. There is.

The invention according to claim 4 is characterized in that, in the invention according to claim 1, 2 or 3, a three-dimensional target corresponding to the surface of the three-dimensional substrate is brought close.

The invention of claim 5 is characterized in that, in the invention of claim 1, 2 or 3, the target is a resistor material.

According to a sixth aspect of the present invention, in the invention according to the first, second or third aspect, an oxide layer is formed on the surface of the substrate, and the ratio of the oxide and the metal is sequentially changed so that the surface is substantially It is characterized by being a pure metal.

[0013]

According to the first aspect of the invention, the target is provided with a slit hole corresponding to the circuit pattern shape, and the side surface of the slit hole is sputtered to transfer the circuit pattern of the sputtering film onto the surface of the substrate in the vicinity of the target. Has been done. In other words, the shape of the slit holes corresponding to the circuit pattern shape is directly transferred to the substrate surface by sputtering as the circuit pattern shape.

Furthermore, the sputtering film of this method is formed with good adhesion without strongly roughening the substrate surface.

In the second aspect of the invention, the circuit pattern of the sputtering film is first formed, and the circuit pattern of the plating film is further formed on the film.
Since the circuit pattern of the sputtering film is directly transferred onto the substrate without changing the shape of the slit hole, and the plating film can be easily formed to be thick, a circuit pattern having a large film thickness can be formed in a short time.

According to the third aspect of the invention, a plurality of the same circuit patterns are formed on the same substrate by sputtering the same substrate a plurality of times using the same target. At this time, by using a target smaller than the substrate and changing the positions of the target and the substrate, it is possible to form a large number of circuit patterns of the same material with the same shape at different positions on the same substrate. Further, by overlapping a part of the circuit pattern, a large continuous circuit pattern having the same repeating unit can be obtained.

Further, by using targets having different materials, slit holes, or materials and slit holes, a large number of circuit patterns having different materials, shapes, or materials and shapes are formed on the same substrate, and a synthesized circuit pattern is obtained. Can be formed.

According to the fourth aspect of the present invention, by using the three-dimensional target corresponding to the three-dimensional substrate surface, the circuit pattern is transferred to the three-dimensional substrate surface as in the above invention.

According to the invention of claim 5, the target is made of a resistor material, the resistor is obtained as a sputtering film, and a thin film resistor circuit pattern is directly formed.

According to the sixth aspect of the invention, an oxide layer is formed on the surface of the substrate, and the ratio of the oxide and the metal is changed in order so that the surface becomes a substantially pure metal. The bonding interface between the substrate and the circuit pattern film serves as an oxide layer to improve adhesion.

[0021]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

The first embodiment will be described below with reference to FIGS. 1 and 3 are perspective views showing a substrate 1 and a target 2 used in this embodiment, and FIG. 2 is an explanatory view showing a formation state of a circuit pattern 6. Also, FIG.
Is a cross-sectional view showing the shape of the slit hole 3 of the target 2, and FIGS. 5 to 7 are schematic views showing the configuration of the plasma chamber 4.

FIG. 1 shows a substrate 1 and a target 2,
In this figure, the substrate 1 is a flat plate made of an insulating material such as ceramics or synthetic resin. Target 2
Uses copper as the metal for the circuit pattern. Various other materials can be used as the metal forming the circuit pattern 6, and representative ones include gold, nickel, silver, palladium, aluminum, and the like. The target 2 is provided with slit holes 3 corresponding to the shape of the circuit pattern to be formed on the surface of the substrate 1, and has a thickness of about 1 mm formed by general machining.

Then, the target 2 is placed on the substrate 1 so as to be in close proximity thereto, and is placed in a vacuum chamber 4 capable of forming plasma, as shown in FIG. Argon gas is introduced into the chamber 4 at a reduced pressure of 10 ⁻³ Torr, and a bias voltage is applied to the target 2 so that the target 2 becomes negative with respect to the chamber 4 to discharge between the target 2 and the chamber 4. The plasma 5 can be formed by. As for the bias voltage for making the target 2 negative, a negative bias voltage may be applied to the target 2 with the chamber 4 at the ground potential, or a positive bias voltage may be applied to the chamber 4 with the target 2 at the ground potential. . For this bias voltage,
It is suitable because about 10 to 1000 V is stably discharged. Besides argon gas, gases such as xenon, krypton, neon or nitrogen can also be used.

As described above, the substantially uniform plasma 5 is generated on the surface of the target 2 opposite to the substrate 1, and the side surface of the slit hole 3 of the target 2 is sputtered, so that the substrate 2 is formed as shown in FIG. The circuit pattern 6 made of a sputtering film can be formed on one surface. That is, the copper atom 2a on the side surface of the slit hole 3 of the sputtered target 2 is in close contact with the portion of the slit hole 3 on the surface of the substrate 1 to transfer the circuit pattern 6.

Here, in order to successfully perform the above-mentioned transfer, it is preferable to make the shape of the slit hole 3 appropriate. As the shape, in the cross-sectional view of the target 2 shown in FIG.
It is appropriate to set the aspect ratio (d / D) in the range of about 0.8 to 1.2 and to provide an inclination such that the slit hole 3 becomes slightly narrower on the substrate 1 side. With such a shape, the probability of hitting the plasma 5 is increased, and copper atoms are efficiently transferred.

By setting the density of the plasma 5 to the order of 10 ¹¹ pieces / cm ³ , the circuit pattern 6 can be formed at a film forming rate of 100 to 300 Å / min.

As a concrete plasma forming chamber 4, for example, an electron impact type shown in FIG. 5, a high frequency excitation type shown in FIG. 6, or a microwave excitation type shown in FIG. 7 can be used. In the electron impact type shown in FIG. 5, a magnet 7, an anode 8 and a hot cathode 9 are arranged in a plasma chamber 4, and a plasma 5 is formed by the hot cathode 9. In the high-frequency excitation type shown in FIG. 6, a high-frequency current is applied to the high-frequency coil 10 to form plasma 5,
In the microwave excitation type shown in (1), the ECR plasma 5 is formed by the magnetic field generated by the microwave generator 11 and the coil 12.

As the chamber 4 for plasma formation,
Although various types of methods as described above are used,
For example, the electron impact type shown in FIG. 5 is applied with a bias voltage of 200 V and discharged at 120 W, whereby a circuit pattern 6 having a copper thickness of 2000 Å can be obtained in 15 minutes. As shown in FIG. 6 or 7, by arranging two sets of the target 2 and the substrate 1 which are close to each other so as to face each other so as to sandwich the plasma 5 in the chamber 4,
The circuit pattern 6 can be formed efficiently. Furthermore, the circuit pattern 6 can be formed efficiently by disposing two or more sets.

Circuit pattern 6 formed as described above
Then, the shape of the slit hole 3 of the target 2 is directly transferred to the surface of the substrate 1 as the shape of the circuit pattern 6.
A circuit pattern 6 made of metal of the target 2 is obtained on the surface of the substrate 1.

Therefore, the circuit pattern 6 can be directly obtained without etching with a resist pattern interposed as in the prior art, so that the circuit pattern 6 can be efficiently formed in a short process without wasting the material. It has become. Therefore, the circuit pattern forming method is suitable for forming the circuit pattern 6 made of particularly expensive metal such as gold or palladium.

Further, since the circuit pattern 6 is formed directly on the surface of the substrate 1 by sputtering, there is no possibility that other extra inclusions exist on the surface of the substrate 1 where the circuit pattern 6 does not exist, and the insulating property is improved. Reliable circuit pattern 6
Can be formed. Further, the circuit pattern 6 of this embodiment can be formed with good adhesion without strongly roughening the surface of the substrate 1.

Example 2 will be described below with reference to the schematic explanatory view showing the manufacturing process of FIG. This example is the same as Example 1.
The insulating substrate 1 has a three-dimensional shape, and the target 2 can be formed in a three-dimensional shape in accordance with the substrate 1, and can be performed in the same manner as in the first embodiment. The details will be described below.

In this figure, the diagram (A) shows the substrate 1, which is made of an insulating material such as ceramics or synthetic resin and has a three-dimensional shape on the surface.
The drawing of (B) shows the target 2, and copper is used as a metal which is a material of the circuit pattern 6. Various other materials can be used as the metal forming the circuit pattern 6. Further, the drawing of (C) shows a cross section of a portion indicated by an imaginary line in the drawing of (B). The target 2 is provided with slit holes 3 corresponding to the circuit pattern shape to be formed on the surface of the substrate 1, and has a thickness of about 1 mm formed by general machining. Further, when the surface of the substrate 1 has a complicated shape, it can be formed by electroforming plating so as to fit the three-dimensional shape perfectly.

The diagram (D) shows the target 2 on the substrate 1 described above.
It shows a state where they are trying to be close to each other. The target 2 is brought into close proximity to the substrate 1 and is placed in a vacuum chamber 4 capable of forming a plasma, and a substantially uniform plasma 5 is generated on the surface of the target 2 opposite to the substrate 1, and a slit of the target 2 is formed. The side surface of the hole 3 is sputtered to form a substrate 1 as shown in FIG.
The circuit pattern 6 made of a sputtering film can be formed on the surface.

Therefore, according to this embodiment, as in the case of the first embodiment, the circuit pattern 6 of the sputtering film having good performance can be efficiently formed on the surface of the three-dimensional substrate 1 in a short process. There is.

The third embodiment will be described below with reference to FIGS. 9 and 10. FIG. 9 is an explanatory view showing the steps of this embodiment, and FIG. 10 is a perspective view of a circuit board obtained by this embodiment.

In FIG. 9, as a first step, FIG. 9A shows a state in which palladium is used as the target 2 and the circuit pattern 6a of palladium is formed on the substrate 1 by the method of the first embodiment. There is. However, unlike the first embodiment, the thickness of the circuit pattern 6a is set to 200 to 900Å. Although it is possible to make it thinner to about several tens of liters, it is set to 200 to 900 liters on the safety side because the plating depositability in the second step of (B) becomes a little worse. With this thickness, the sputtering in the first step can be completed in 2 to 3 minutes.

Thereafter, in the second step of (B), electroless copper plating is performed using the above-mentioned circuit pattern 6a as a plating nucleus to form a circuit pattern 6b of a copper plating film of about 10 μm on the circuit pattern 6a. Then, a circuit board as shown in FIG. 10 is obtained.

The target 2 used in the first step is copper and is sputtered for 15 minutes to obtain a circuit pattern 6a having a copper thickness of 2000Å. The circuit pattern 6a is used as an electrode and the circuit pattern 6b of the electrolytic copper plating film is used as the circuit pattern. 6a
You may form it on top. Alternatively, an electroless plating film may be used instead of the electrolytic plating film, and a plating film of electroless nickel, gold plating, or the like may be stacked and formed.

As described above, in this embodiment in which the plating films are formed in an overlapping manner, it is complicated to form the plating nuclei in the pattern shape on the surface of the substrate 1 in the conventional method of forming the pattern only with the plating films. On the other hand, since this can be performed by sputtering for several minutes, it is easy and the thick film circuit pattern 6 can be easily formed in a short time.

The fourth embodiment will be described below with reference to FIG. 11 or FIG. These figures show schematics of different circuit patterns.

In this embodiment, different circuit patterns are sequentially formed on the same substrate 1 by the method shown in the first embodiment to form a combined circuit pattern.

FIG. 11 shows an example in which a target 2 having different slit holes 3 is used. First, (A)
The circuit pattern 6a is formed on the substrate 1 using the target 2a having the slit holes 3a corresponding to the circuit pattern 6a. Next, the circuit pattern 6b is formed on the substrate 1 by using the target 2b having the slit holes 3b corresponding to the circuit pattern 6b of (B). At this time, by making the positional relationship between the substrate 1 and the target 2b substantially the same as that at the beginning, the circuit pattern 6c in which (C) is synthesized can be obtained.

FIG. 12 shows an example in which the same target 2a is used. First, the circuit pattern 6a is formed on the substrate 1 by using the target 2a having the slit holes 3a corresponding to the circuit pattern 6a of (A). . Next, the same target 2a is displaced from the substrate 1 by the width of the circuit pattern 6a to form the same circuit pattern 6a (B) on the substrate 1. In this way, the circuit pattern 6c of (C)
Is synthesized.

As described above, in this embodiment, different circuit patterns can be formed by preparing the target 2 provided with the slit holes 3 corresponding to several kinds of basic circuit patterns.

The circuit pattern can be synthesized by changing the material of the target 2. For example, target 2
A conductive material such as copper, aluminum, silver or gold is used as a and a resistor material such as ruthenium oxide or nichrome alloy is used as the target 2b to form a circuit pattern 6c, thereby having a resistor. A circuit board can be obtained. In this case, since the resistor circuit pattern 6b is formed as a sputtering film, a high-performance thin film resistor circuit pattern is directly obtained.

The circuit pattern 6 formed by another method such as a plating method can be combined. In this case, it is preferable that each circuit pattern 6 can be formed by an optimum method. For example, it is considered that the circuit pattern 6 requiring a thickness is formed by plating or the like.

The fifth embodiment will be described below with reference to FIGS. 13 to 14. FIG. 13 is an explanatory view showing one manufacturing process of this embodiment, and FIG. 14 is an explanatory view showing the structure of the joint portion between the circuit pattern 6 and the substrate 1 obtained in this embodiment.

FIG. 13 is an explanatory view showing a state in which the plasma 5 is generated and the slit holes 3 are sputtered. In this figure, the target 2 made of pure copper is exposed to the atmosphere and the surface thereof is slightly oxidized. This target 2 was used without cleaning, as done in Example 1,
The circuit pattern 6 is formed on the substrate 1 by sputtering.

FIG. 14 shows the joint between the circuit pattern 6 and the substrate 1 obtained as described above. As shown in this figure, the portion 6a of the circuit pattern 6 that corresponds to the interface between the substrate 1 and the circuit pattern 6 becomes cuprous oxide having a thickness of several to several tens of liters, and the proportion of cuprous oxide gradually decreases and the oxidation cuprous oxide is gradually reduced. It becomes a mixed layer 6b of 1-copper and pure copper, and finally becomes pure copper 6c. Since the cuprous oxide thus formed is strongly bonded to the substrate 1, the circuit pattern 6 can be strongly bonded to the ceramics such as alumina or the substrate 1 such as polyimide.

In the structure of the circuit pattern 6 in which the oxide layer is changed to a pure metal, pure metal is used as the target 2 and oxygen gas is introduced into the chamber 4 at the initial stage of sputtering, or The sputtering can be performed in two steps, using the cuprous oxide target 2 in the initial stage, and then using the pure copper target 2, and the like.

Although the above example describes the case of copper, the circuit pattern is not limited to copper, but other metal such as nickel or aluminum can be formed by forming the oxide layer 6a at the bonding interface. The adhesion of 6 can be improved.

As described above, in this embodiment, the circuit pattern 6 is directly formed on the surface of the substrate 1 by sputtering, which does not require a resist pattern as in the conventional case and an etching process is also required. It is not. Therefore, according to the present embodiment, the circuit pattern 6 having good performance such as insulation can be formed in a simple and efficient process, and can be applied to the three-dimensional substrate 1.

[0055]

According to the invention of claim 1, the slit hole shape of the target corresponding to the circuit pattern shape is directly transferred to the substrate surface as the circuit pattern shape, and the circuit pattern of the same material as the target is formed on the substrate surface. Has been obtained. Therefore, the circuit pattern can be directly obtained without the interposition of the resist pattern as in the conventional case, so that the process is short and the circuit pattern is efficiently formed without wasting the pattern material.

Further, since the circuit pattern is formed directly on the surface of the substrate, there is little possibility that an extra substance such as an etching residue or a resist residue will be present on the surface of the substrate where the circuit pattern does not exist, and the circuit having a good insulating property It can be a pattern.

Further, the sputtering film of this method can be formed with good adhesion without strongly roughening the surface of the substrate, as compared with the conventional method of adhering an electrolytic copper foil or the method of forming a plating film. .

According to the second aspect of the present invention, a circuit pattern having a plating film can be formed on the sputtering film. At this time, since the circuit pattern of the sputtering film is directly transferred onto the substrate without changing the shape of the slit holes, the circuit pattern is simpler than the conventional plating nucleation method.
Moreover, since it is easy to form the plating film with a large film thickness, it is possible to form a circuit pattern with a large film thickness in a short time.

According to the third aspect of the present invention, a large number of circuit patterns having the same shape and the same material can be formed at different positions on the same substrate, and a large continuous circuit pattern having the same repeating unit can be formed. it can.

Further, a large number of circuit patterns having different materials, shapes or different materials and shapes can be formed on the same substrate to form a combined circuit pattern. For example, a conductor metal circuit pattern and a thin film resistor circuit pattern can be combined to form a conductor circuit pattern having a thin film resistor.

According to a fourth aspect of the present invention, the circuit pattern of the target slit hole shape is directly transferred to the surface of the three-dimensional substrate, and the circuit pattern of the sputtering film having the above-described good performance is also formed on the surface of the three-dimensional substrate. Can be efficiently formed in a short process.

According to the fifth aspect of the present invention, the circuit pattern of the resistor is formed as a sputtering film, and the thin film resistor circuit pattern is directly obtained.

According to the sixth aspect of the invention, since the bonding interface between the substrate and the circuit pattern film can be an oxide layer,
A circuit pattern with good adhesion can be formed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a substrate and a target according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a formation state of a circuit pattern according to the embodiment.

FIG. 3 is a perspective view showing a substrate and a target in the above embodiment.

FIG. 4 is a sectional view showing a shape of a slit hole of a target in the above embodiment.

FIG. 5 is a schematic view showing a configuration of a plasma chamber in the example of the same.

FIG. 6 is a schematic view showing a configuration of a plasma chamber in the same example.

FIG. 7 is a schematic view showing a configuration of a plasma chamber in the same example.

FIG. 8 is a schematic explanatory diagram showing a manufacturing process of Example 2 of the present invention.

FIG. 9 is a schematic explanatory diagram showing the manufacturing process of Example 3 of the present invention.

FIG. 10 is a perspective view showing a circuit board obtained according to the embodiment.

FIG. 11 is a schematic diagram showing a circuit pattern according to a fourth embodiment of the present invention.

FIG. 12 is a schematic view showing a circuit pattern in the above embodiment.

FIG. 13 is an explanatory diagram showing one manufacturing process of Example 5 of the present invention.

FIG. 14 is an explanatory diagram showing a structure of a joint portion between a circuit pattern and a substrate, which is obtained in the same example.

[Explanation of symbols]

 1 substrate 2 target 3 slit hole 4 chamber 5 plasma 6 circuit pattern 7 magnet 8 anode 9 filament 10 high frequency coil 11 microwave generator 12 coil

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sakuo Kamada 1048, Kadoma, Kadoma, Osaka Prefecture, Matsushita Electric Works Co., Ltd. (72) Yoshiyuki Uchino, 1048, Kadoma, Kadoma, Osaka Prefecture (72) Inventor Nakajima Isao Matsuda Electric Works Co., Ltd. 1048 Kadoma, Kadoma City, Osaka Prefecture (72) Inventor Toshiyuki Suzuki 1048 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd.

Claims (6)

[Claims] 1. A target having a slit hole corresponding to a circuit pattern shape on a substrate surface is brought close to the target, and substantially uniform plasma is generated on a target surface opposite to the substrate to sputter the side surface of the slit hole of the target. A method for forming a circuit pattern, comprising: 2. A target having slit holes corresponding to the circuit pattern shape is brought close to the substrate surface, and substantially uniform plasma is generated on the target surface opposite to the substrate to sputter the side surface of the target slit hole. A circuit pattern forming method, which comprises forming a circuit pattern made of a plating film on the formed circuit pattern. 3. A target having slit holes corresponding to the circuit pattern shape is brought close to the surface of the substrate, and a substantially uniform plasma is generated on the target surface opposite to the substrate to sputter the side surface of the slit hole of the target. In the method of forming a circuit pattern, a method for forming a circuit pattern is characterized in that a plurality of or the same target is sequentially used to perform sputtering a plurality of times on the same substrate to form the circuit pattern on the same substrate in an overlapping manner. 4. A three-dimensional target corresponding to the surface of a three-dimensional substrate is brought into proximity.
2. The circuit pattern forming method according to 2 or 3. 5. The circuit pattern forming method according to claim 1, 2 or 3, wherein the target is a resistor material. 6. The substrate according to claim 1, wherein an oxide layer is formed on the surface of the substrate, and the ratio of the oxide and the metal is sequentially changed so that the surface becomes a substantially pure metal. 3. The method for forming a circuit pattern according to item 3.