JPH02875B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for manufacturing fine thick film conductive patterns with high density and high reliability.
Fine thick-film conductive patterns are required in fields such as small coils, high-density connectors, and high-density wiring that require high current values. The wire winding method is normally used to manufacture coils, but it is difficult to manufacture small coils using this method.
Moreover, variations occur in the state of the winding wire. Also,
The so-called printed coil, which is made by etching 35 μm copper foil, cannot obtain a fine pattern because of side etching, and only a pattern of 2 to 3 lines/mm can be obtained at most, making it difficult to manufacture small coils using this method. However, as motors have become smaller in recent years, there has been a demand for the development of fine coils having a fine pattern of 5 lines/mm or more.

The present inventors first formed a resist on a part other than the pattern part on a thin metal plate, formed a conductor by electrolytic plating on the pattern part using the metal thin plate as a cathode, and then used the obtained conductor as an insulator. We proposed a method to obtain a thick film fine pattern conductor by attaching a thin metal plate to a substrate with the thin metal plate facing up and then removing the thin metal plate by etching.

However, since the entire surface of the thin metal plate is etched, the thin metal plate cannot be used as a conductor, and the etching liquid is highly fatigued, resulting in a large consumption of etching liquid.

The present invention relates to an improved method for manufacturing fine thick film conductive patterns for economically producing thick film conductive patterns.

That is, in the present invention, a resist is formed on one surface (a) of a thin metal plate of zinc, aluminum, or tin having a thickness of more than 10 μm and less than 200 μm, except for the conductor pattern, and the thin metal plate is used as a cathode (a). A conductor is formed on the conductor pattern part of the surface by electrolytic plating using a copper pyrophosphate plating solution at a cathode current density of 5 A/dm ² or higher, and then etching resistance is applied to the surface (b) of the thin metal plate on which no resist is formed. A fine thick film conductive pattern with a line density of 5 lines/mm or more and a thickness of 20 μm or more, characterized in that after forming an insulating layer, the resist on the (a) side is peeled off and the thin metal plate is etched away in the form of a conductive pattern. It provides a manufacturing method.

Here, surface (a) and surface (b) are arbitrary surfaces, and the thin metal plate itself does not have different surfaces. Note that the pattern refers to a shape or pattern that forms a part through which electricity is conducted, such as a conductor or a resistor, and is a part that is usually called a circuit.

Since the method of the present invention etches and removes only unnecessary parts of the thin metal plate, the thin metal plate in the conductor pattern area acts as a conductor, increasing the actual thickness of the conductor pattern, reducing consumption of etching solution, and saving resources. can also contribute. In addition, it is excellent in maintaining the conductor shape and is easy to handle.
Furthermore, since it is possible to make the insulating layer thinner, the method of the present invention is also effective in improving the space factor.
As is clear from the above points, the production method of the present invention is industrially superior.

The thin metal plate used in the present invention may be any material as long as it is a conductor and can be etched, but it is preferably one that has etching characteristics different from electroplated conductors; in this case, the thin metal plate can be etched. During removal, the electrolytically plated conductor is not etched, allowing highly accurate etching of the metal thin plate. Suitable materials include aluminum, tin, and zinc. Moreover, the preferable range of film thickness is 10 to 200 μm. If the film thickness is 10 μm or less, it is difficult to handle and the plating film thickness tends to be uneven. In addition, for film thicknesses of 200μm or more,
Etching removal takes time and productivity decreases.

As a method for forming a resist on a portion other than the pattern portion used in the present invention, screen printing or gravure printing may be used, but it is preferable to use a photoresist that can easily form a fine pattern. As for the formation method,
It can be obtained through coating, exposure, and development processes. Photoresists include Eastman Kodak's KPR, KOR, KPL, KTFR, KMER,
Tokyo Ohkasha's TPR, OMR81, Fuji Pharmaceutical Co., Ltd.
There are negative types such as FRS and positive types such as KADR from Eastman Kodak Co. and AZ-1350 from Shipley, but those with excellent plating resistance are preferred, and negative types are particularly preferably used. A dry film resist can also be used.
The thicker the film, the more useful it will be in preventing thickening.
If it is too thick, it becomes impossible to obtain a fine pattern, so 0.1 to 50 μm, particularly 1 to 10 μm is preferable. If the thickness is 0.1 μm or less, pinholes are likely to occur.

In the present invention, electrolytic plating is performed on a thin film pattern with a thickness of 20 μm or more and a linear density of 5.
In order to thicken the pattern with a thickness of more than 1mm/mm, use a copper pyrophosphate plating solution with a cathode current density of 5A/mm.
Electrolytic plating is required at dm ² or higher. The upper limit of the cathode current density is determined by the burn.

Figures 1 and 2 show the cross-sectional growth of an electroplated layer when electrolytically plated using a copper pyrophosphate plating solution at cathode current densities of 2 A/dm ² and 5 A/dm ^2. 5μm thick, resist width 40μm, interval 85μm (line density 8 lines/mm)
This is an example in which a conductive layer is grown by electrolytic plating on a resist pattern.

In electrolytic plating with a cathode current density of 2A/ ^dm2 ,
The electrolytic plating layer grows at about twice the speed in the width direction as in the thickness direction, and when it grows 20 μm in the thickness direction, it collides with the adjacent plating layer and short-circuits (Figure 1), whereas the cathode current In electrolytic plating with a density of 5 A/dm ² , on the other hand, the plating layer grows at a rate nearly twice as fast in the thickness direction as in the width direction (Figure 2).

Figure 3 shows the growth curve of the electroplated layer obtained by plotting the length in the growth thickness direction against the growth length in the width direction of the electroplated layer obtained by the method explained in Figures 1 and 2. In electrolytic plating using a copper pyrophosphate plating solution, the plating layer grows in an anisotropic direction in which the plating layer growth rate in the thickness direction is significantly higher than the plating layer growth rate in the width direction at a cathode current density of 5A/
This shows that this occurs at dm ² or higher.

Another important factor in electrolytic plating is the plating film thickness/pattern spacing ratio.
By setting this ratio to 1.4 or more, particularly 2.0 or more at the above cathode current density, thickening in the width direction is further reduced and the film can be selectively plated in the thickness direction.

These phenomena described above are remarkable when adjacent patterns are at equal potential, and the present invention maximizes these effects.

Although there is no particular restriction on the electrolytic plating film thickness, the present invention is particularly effective when the electrolytic plating film thickness is thick, and 1.5
~200μm, especially 20-200μm, even 35-200μm
is the preferred range.

Although the method of the present invention can be used where the wiring density is low, it is industrially suitable for wiring densities of 3 lines/mm or more, particularly 5 lines/mm or more. Furthermore, the present invention is particularly suitable for cases where the conductive pattern has a space factor of 50% or more.
It is suitable if it is 70% or more.

In the present invention, the etching-resistant insulating layer is preferably an insulating varnish used for coils, etc. Specifically, polyimide, polyamideimide,
Preferred are polymers such as polyester, polyurethane, and epoxy resin, as well as polyester-isocyanate, phenol resin-butyral, phenol resin-nitrile rubber, epoxy-nylon, and epoxy-nitrile rubber polymers. The forming method may be a commonly used coating method or the like.

It is also possible to attach it to an insulating substrate. In this case, as the insulating substrate, a film substrate, a laminated substrate, a glass substrate, a ceramic substrate, a metal substrate coated with an insulating layer, etc. can be used, and a film-like substrate is particularly preferred. All film substrates can be used, such as polyester film, epoxy film, polyimide film, polyparabanic acid film, and triazine film. Film is preferred.

To remove the resist, use a commercially available remover.
For example, spraying or dipping may be performed using Resist Stripper J-100 manufactured by Indust-Ri-Chem-Laboratory. However, it is necessary to choose a stripping solution that does not attack the thin metal plate or plated metal.

In the present invention, the thin metal plate is removed by etching by spraying or dipping using a solution that dissolves the used thin metal plate. Furthermore, when aluminum, tin, or zinc is used as the thin metal plate, it is preferable not to etch the electrolytically plated conductor, for example, by etching with an alkaline aqueous solution, but it is also possible to etch with an acidic aqueous solution such as dilute hydrochloric acid.

After etching, insulation and reliability are improved.
In order to improve mechanical strength, a protective layer may be provided by impregnation, molding, coating, etc. As a protective layer, heat resistance, moisture resistance, insulation,
A material with excellent adhesiveness is preferable, and the material is as follows:
The materials listed above as materials for the etching-resistant insulating layer may be used.

It is also possible to laminate a plurality of fine thick-film conductive patterns subjected to the above-mentioned treatment, and in this case, electrical connections can be made between the upper and lower conductive patterns by drilling and through-hole connection.

The fine thick film conductive pattern obtained by the present invention is industrially particularly suitable for use in small coils with low resistance, high-density connectors, high-density wiring, and the like.

EXAMPLES In order to further clarify aspects of the present invention, examples will be described below, but the present invention is not limited to the following examples, and various modifications can be made.

Example 1 After drying a negative resist "Microresist 747-110cst" manufactured by Eastman Kodak Co., Ltd. on a thin aluminum plate with a film thickness of 40 μm, it was applied on one side to a film thickness of 5 μm and prebaked to form a circuit pattern mask. The film was exposed to light using a high-pressure mercury lamp through the film, developed using a special developer and rinse solution, and post-baked to form a resist in areas other than the pattern area.

Next, using a copper pyrophosphate plating solution manufactured by Harshyou Murata Co., Ltd., and using a thin aluminum plate as a cathode, a 100 μm thick copper layer was formed on the patterned portion by electrolytic plating. After that, an insulating substrate was coated with phenol resin-nitrile rubber adhesive "XA564-4" manufactured by Postic Co., Ltd. to a film thickness of 5 μm after drying on a polyimide film "Kapton" (film thickness 25 μm) manufactured by DuPont. On top, the above electrolytically plated material was placed with the thin aluminum plate facing down at 150℃ for 30 minutes.
After applying heat and pressure for 1 minute, the resist was removed using Resist Strip J-100 liquid manufactured by Industrie Chemie Laboratory, and then the aluminum thin plate was coated with a solution of 36% by weight hydrochloric acid diluted with water in a ratio of 2:3. Etching was removed and epoxy surface coating materials (ME-264 main agent and HV-106 manufactured by Nippon Pernox Co., Ltd.) were removed.
The surface was overcoated with a mixture of curing agents at a weight ratio of 100:27. As a result, the wiring density is 10 wires/
A fine thick film conductive pattern with a thickness of 140 μm (including an inner aluminum layer of 40 μm) and a pattern interval of 15 μm was obtained.

Example 2 A negative photoresist “Microresist” manufactured by Eastman Kodak Co., Ltd. was applied on a thin tin plate with a film thickness of 20 μm.
747-110cst" was dried, coated on one side to a film thickness of 3 μm, pre-baked, exposed to a high-pressure mercury lamp through a circuit pattern mask, developed using a special developer and rinse solution, and post-baked. Then, a resist was formed on the parts other than the pattern part.

Next, using a copper pyrophosphate plating solution manufactured by Hersho Murata Co., Ltd. and using a thin tin plate as a cathode, a 50 μm thick copper layer was formed on the patterned portion by electrolytic plating. After that, an epoxy surface coating material (a mixture of ME-264 main agent and HV-106 curing agent manufactured by Nippon Pernox Co., Ltd. in a weight ratio of 100:27) was applied to the surface opposite to the surface on which copper was formed on the pattern. A thin tin plate was coated to a film thickness of 10 μm. After removing the resist using Resist Strip J-100 solution manufactured by Industrie Chemie Laboratory, the thin tin plate was etched away with a solution prepared by diluting 36% by weight hydrochloric acid with water at a ratio of 2:3, and the epoxy surface coating material ( ME-264 main agent and HV-106 manufactured by Nippon Pernox Co., Ltd.
The surface was overcoated with a mixture of curing agents at a weight ratio of 100:27. As a result, the wiring density is 15 lines/
A fine thick film conductive pattern with a thickness of 70 μm (including a 20 μm tin layer) and a pattern interval of 10 μm was obtained.

Example 3 A negative photoresist “Microresist” manufactured by Eastman Kodak Co., Ltd.
747-110cst" was dried, coated on one side to a film thickness of 3 μm, prebaked, exposed on both sides with a high-pressure mercury lamp through a circuit pattern mask, developed using a special developing solution and rinsing solution, and then post-coating. Baking was performed to form a resist on portions other than the pattern portion.

Next, using a copper pyrophosphate plating solution manufactured by Harshyou Murata Co., Ltd., and using a thin zinc plate as a cathode, a 150 μm thick copper layer was formed on the pattern portion by electrolytic plating. After that, an epoxy surface coating material (a mixture of ME-264 main agent and HV-106 curing agent manufactured by Nippon Pernox Co., Ltd. in a weight ratio of 100:27) was applied to the zinc plate on the side opposite to the side where copper was formed on the pattern area. A thin plate was coated with a film thickness of 10 μm. Industrie Chemie Laboratory Co., Ltd. Resist Strip J
-100 solution, and then etched the zinc thin plate with a solution prepared by diluting 36% by weight hydrochloric acid with water at a ratio of 2:3. The surface was overcoated with a mixture of HV-106 hardener in a weight ratio of 100:27. As a result, the wiring density is 6/
mm, conductor film thickness 200 μm (including 50 μm zinc layer),
Fine thick film conductive patterns with a pattern interval of 30 μm were obtained.

[Brief explanation of drawings]

Figure 1 shows the growth of the electrolytically plated layer when electrolytically plated at a cathode current density of 2A/ ^dm2 , and Figure 2 shows the growth of the electrolytically plated layer when electrolytically plated at a cathode current density of 5A/ ^dm2 . FIG. 3, which is a diagram showing the growth status of the electrolytically plated layer, is a growth curve of the electrolytically plated thickness by electrolytically plating using a copper pyrophosphate plating solution. In the figure, 1 is a metal thin plate, 2 is a resist, and 3 is a conductor layer.

Claims (1)

[Claims] 1. A resist is formed on one side (a) of a thin metal plate of zinc, aluminum or tin with a thickness of more than 10 μm and less than 200 μm, except for the conductor pattern part, and the conductor pattern part on the side (a) is formed using the thin metal plate as a cathode. Using a copper pyrophosphate plating solution, the cathode current density was 5A/ ^dm2.
In the above steps, a conductor is formed by electrolytic plating, and then an etching-resistant insulating layer is formed on the surface (b) of the thin metal plate on which the resist is not formed, and then the resist on the surface (b) is peeled off to form the thin metal sheet as a conductor. A method for producing a fine thick film conductive pattern with a linear density of 5 lines/mm or more and a thickness of 20 μm or more, which is characterized by etching removal in a pattern.