JPS6189697A - Circuit formation for composite substrate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a circuit forming method for forming fine circuits on the surface of a thermally sprayed coating of a composite substrate.

[Conventional technology]

Generally, a masking technique is employed to form a circuit on the surface of a thermally sprayed coating of a composite substrate, which is formed by thermally spraying an insulating oxide onto the surface of a metal substrate.

This technique is a method in which the surface of a thermally sprayed coating is covered with a metal mask according to the pattern of the circuit to be formed, and then a conductor such as copper powder is thermally sprayed to form a circuit. However, with conventional masking technology, the conductor is also sprayed onto the metal mask, so the service life of the metal mask is extremely short, and work to secure the metal is required, making it difficult to achieve economic efficiency and mass production. However, the width of the circuit that can be formed is limited to 1 Rms, the line spacing is 3, and the limit is about +u+), making it difficult to form fine circuits.

[Problem that the invention seeks to solve]

The present invention has been proposed in view of the above-mentioned conventional drawbacks, and provides a method for forming a circuit on a composite substrate that is economical and mass-producible and can form a fine circuit without using a metal mask. That is.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention has developed a composite substrate in which a thermally sprayed coating is formed by thermally spraying an insulating oxide on the surface of a metal substrate. This method is characterized in that after resist printing is carried out and a conductor is thermally sprayed thereon, the resist is removed using an organic bath medium, a weakly acidic aqueous solution, or a weakly alkaline aqueous solution.

At this time, the composite board that forms the circuit is
A metal substrate has a through hole, and an insulating oxide is thermally sprayed on the surface of the substrate including the surface of the through hole to form a sprayed coating, and a metal substrate has a horizontal shape at the end. It is also possible to form a sprayed coating by spraying an insulating oxide onto the surface of the substrate, including the surface of the protrusions, with the protrusions arranged in a shape.

[Effect]

In the method for forming a circuit on a composite substrate of the present invention employing the above-mentioned means, the resist printing itself corresponding to the pattern of the circuit to be formed, which is applied to the surface of the thermally sprayed coating on the composite substrate, is different from that in conventional masking techniques. It acts as a metal mask, and the donor can be sprayed directly onto it, and if the resist is removed with an organic solvent, weakly acidic aqueous solution, or weakly alkaline aqueous solution, fine circuits will be formed on the surface of the thermally sprayed coating. become.

[Embodiment 11] The present invention will be specifically described below based on embodiments shown in the drawings.

! 1 is a process diagram showing an embodiment of the circuit forming method according to the present invention. 3. In (A), 1 is A4Fe.

For a metal substrate such as CB, M□, etc., (b) proposes a process in which the surface of the substrate 1 is subjected to a blast treatment. Next (c), AJl1205. Mg
o.

Sprayed coating 2 by spraying an insulating oxide such as Z r 02
The composite substrate A is constructed by three steps (a), (b), and (c). Next) shows a step of applying resist printing 3 on the surface of the thermal spray coating 2 of the composite substrate A in accordance with the pattern of the circuit to be formed.

Next, (E) shows a step of spraying a conductor 4 such as Cu from above onto the surface of the sprayed coating 2 on which the resist printing 3 has been applied.

At this time, in order to prevent the resist of the resist printing 3 from being melted by the thermally sprayed conductor 4, the composite substrate A is cooled during thermal spraying, the viscosity of the resist is increased, and the thickness of the resist printing 3 is increased from 40 mm to 40 mm. It is desirable to set the thickness to about 50μ. However, a commonly used resist is sufficient. Next, after spraying the conductor 4, the process of removing the resist using an organic solvent, a weakly acidic aqueous solution, or a weakly alkaline aqueous solution is shown. Above (a), (b), (c), ni), (e).

In the circuit forming method of the present invention in which a circuit is formed through the step (f), the resist printing 3 itself serves as a metal mask, and a metal mask is not required. It is possible to form a circuit.

Next, an example of an experiment conducted to fully confirm the effectiveness of the present invention will be explained.

The composite substrate used in the experiment is 50mm x 50n x
Made of 2rRIIt Al, its surface is A-43,80#
After shot blasting at a pressure of 5 Ky/ad using a shot material of be.

Table 1 Resist ink (Asahi Chemical Research Institute FdFL-500) was applied to the surface of the thermal spray coating of this composite board to a thickness of approximately 44 to 10 μm as a conductor.
μ CU powder particles were thermally sprayed under the conditions shown in Table 11.

Table ■ Cutting gas (A r ) pressure; 25 psi'
Next, the resist was removed using a trichlorethylene-based organic solvent, the line width and line spacing of the formed circuit were measured using a surface roughness meter, and the presence or absence of line breakage in the circuit was confirmed using a microscope. The line spacing can be made finer to about 300μ, and the line spacing can be made finer to about 500μ.Compared to conventional masking technology, it is possible to make the circuit metal formed on the surface of the thermal sprayed coating of a composite substrate even finer, making it fully practical. It was confirmed that there is.

FIG. 2 is a process diagram showing another embodiment of the present invention. (a
), 1 is a metal substrate, S indicates a through hole provided at a suitable position in the substrate 1, and the surface of the substrate 1 including the surface of the through hole S is subjected to a plastic treatment. (
b) shows a step of spraying an insulating oxide onto the surface of the substrate 1, including the surface of the through-hole S which has been subjected to the blast treatment, using a plasma gun to form a thermal spray coating 2, and (a)
Composite substrate B is constructed through the process of t(b).

Incidentally, at this time, the thermal spray coating 2 may be partially formed on the back side of the substrate 1. Next, (c) shows a step of applying resist printing 3 on the surface of the thermal spray coating 2 including the through poles S of the composite substrate B in accordance with the pattern of the circuit to be formed.

Next, (d) shows a step of thermally spraying a conductor i from above onto the surface of the thermally sprayed skin M2 on which the resist printing 3 has been applied.

Next, (e) shows a step of removing the resist print 3 with an organic solvent, a weakly acidic aqueous solution, or a weakly alkaline aqueous solution after thermally spraying the conductor 4t.

Note that if the opening of the through hole S is tapered, the thickness of the sprayed coating 2 can be increased even inside the through hole S, and the reliability of insulation can be improved.

By using the composite board B having the through holes S in this way, circuits can be formed on both sides of the composite board B,
Since the terminals can be caulked through the through holes S, the bonding strength of the terminals is strong, and electrical components can be mounted with high density.

Next, FIG. 3 is a perspective view of a composite substrate used in yet another embodiment of the present invention.

Composite boards that use a metal board as a part have good thermal conductivity, but because the board is metal, it is not possible to take the terminals directly from the board, and the terminals must be drawn out separately. . However, as shown in FIG. 3, an insulating oxide is applied to the surface of the substrate 1, including the surface of the protrusions T, of a metal substrate 1 having protrusions T arranged in a comb shape at the end. When the entire circuit is formed using the conductor 4 using the composite board C on which the thermal spray coating 2 is formed by thermal spraying, it is possible to connect to another electrical component via the protrusion T, and there is no need to draw out a separate terminal from the board. This makes wiring extremely easy and further improves reliability.

〔Effect of the invention〕

As is clear from Examples and Experiment 1j, according to the present invention, there is no need for a metal mask, and the resist printing itself can serve as a metal mask.
It eliminates the complexity associated with the use of metal masks, is more economical and mass-producible than conventional masking technology, and allows for miniaturization of the circuits formed, among other things. This method has the following advantages and can provide a method for forming a circuit on a composite substrate that is extremely effective in practice.

[Brief explanation of the drawing]

Figures 1 and 2 are process diagrams showing different embodiments of the circuit forming method according to the present invention, and Figure 3 is a perspective view (2) of a composite substrate used in still another embodiment of the present invention. . 1... Substrate, 2... Thermal spray coating, 3... Resist printing, 4... Conductor, A, B, C... Composite board, S...
Through hole T...Protruding part Fig. 1 Fig. 2 Fig. 3

Claims (3)

[Claims] (1) Resist printing according to the pattern of the circuit to be formed is applied to the surface of the thermal sprayed coating of a composite substrate in which an insulating oxide is thermally sprayed on the surface of a metal substrate to form a thermal sprayed coating,
1. A method for forming a circuit on a composite substrate, comprising spraying a conductor thereon and then removing the resist using an organic solvent, a weakly acidic aqueous solution, or a weakly alkaline aqueous solution. (2) A composite substrate is used in which a metal substrate has through holes and an insulating oxide is thermally sprayed on the surface of the substrate including the surface of the through holes to form a thermal spray coating. 2. A method for forming a circuit on a composite substrate according to item 1. (3) A metal substrate has protrusions arranged in a comb shape at its ends, and an insulating oxide is thermally sprayed on the surface of the substrate including the surface of the protrusions to form a sprayed coating. 2. The method for forming a circuit on a composite substrate according to claim 1, characterized in that the composite substrate is made of a composite substrate.