JP4427728B2 - Printed wiring board and circuit forming method thereof - Google Patents

Description

  The present invention relates to a circuit forming method and a wiring board for forming a conductive circuit by panel copper plating and pattern plating for partial plating on the same flat substrate surface when forming a conductive circuit on a printed wiring board. In particular, the present invention relates to a printed wiring board for forming a circuit having an operation function and a contact function at a predetermined position of a printed wiring board having a three-dimensional solid circuit, and a circuit forming method thereof.

Conventionally, when a conductive circuit is formed on a printed wiring board, a planar conductive circuit is formed by designing the thickness of circuit conductors on the same flat substrate surface to be uniform and changing the conductor width.
In the multilayer printed wiring board, the thickness of the circuit conductors in each layer separated by the insulator may be changed, but the thickness of the circuit conductors in the same layer is not changed to a three-dimensional circuit. For example, there has been no demand for a printed wiring board for forming a three-dimensional circuit in a contact area or an operation area by intentionally setting the thickness of circuit conductors having the same configuration on the same base surface or in the same layer to a design value that is intentionally different by 5 μm or more.

As a circuit forming method having a three-dimensional solid circuit, there is a method of forming a conductive circuit on the surface of a synthetic resin molded product.
As an example, there is a circuit forming method for a synthetic resin molded product disclosed in Japanese Patent Laid-Open No. 8-148809.
In this method, the outer surface of the synthetic resin molded article has a three-dimensional surface shape, and the outer surface of the three-dimensionally molded synthetic resin molded article is subjected to metal coating to form a circuit conductor. The thickness of the circuit conductor on the outer surface of the synthetic resin molded product is such that a conductor is formed on the surface of the synthetic resin molded product in a planar (two-dimensional) manner to form a conductive circuit.
The synthetic resin molded product forming the three-dimensional circuit conductor of this synthetic resin molded product has problems such as thin plate, double-sided, large size, side terminal, and refractive strength.
JP-A-8-148809.

Component elements and various functional components are mounted on a printed wiring board, and functional components having an operation function, a display function, a switch function, a contact function, and the like are provided. That is, an operation terminal, a control terminal, and a display terminal used for illumination level, display selection, operation function selection, operation state selection, and the like are used.
The functional parts formed by mounting the above-described component elements and various functional parts are diversified, and the demand for printed wiring boards having three-dimensional circuits with different three-dimensional conductor thickness is increasing in the printed wiring board as a base. It was.
Using these three-dimensional circuits with different conductor thicknesses, contact functions such as on / off switch, multi-stage selector switch, and push switch, display functions such as LED and indicator lamp, and selection of operation functions for various settings and operation status A printed wiring board provided with a three-dimensional circuit used for selection has become necessary.

By the way, a photosensitive dry film for circuit formation is used to form a printed wiring board having a three-dimensional circuit with different three-dimensional conductor thickness by a conventional printed wiring board manufacturing method instead of a special device or a special construction method. However, there is a method of repeating the formation of circuits by copper plating and etching one step at a time from the lowest conductor thickness, and stacking and forming three-dimensional step circuits, but the same number of copper plating and etching as the number of step circuits is required. Thus, there was no photosensitive dry film that could withstand this copper plating and etching (plating mask and etching mask), and it was difficult to ensure quality reliability.
In addition, since circuit formation by copper plating and etching is repeatedly performed, the deviation of each step circuit, deformation, poor positional accuracy, conductor thickness variation, and work efficiency are poor.
Further, when plating such as nickel, gold, silver, and rhodium is performed on the copper plating, poor adhesion between the copper plating of each step circuit and the above-described dissimilar metal plating occurs.

According to the first aspect of the present invention, when the conductive circuit is formed on the printed wiring board, the first dissimilar metal plating conductor is partially formed on the first panel copper plating conductor formed on the copper clad laminate. A step of partially forming a second dissimilar metal plating conductor on the second panel copper plating conductor covering the conductors entirely, and the first dissimilar metal plating conductor and the second In the process of etching using different metal plating conductors as etching resist masks, at least two steps (two types) of thick conductors made of (copper plating + different metal plating other than copper) on the same substrate surface are stepped This is a circuit forming method to be formed.

  Moreover, in partial pattern plating to form a desired thickness conductor, circuit formation using partially formed pattern plating of a dissimilar metal other than copper including any one of nickel, gold, silver, and rhodium as an etching resist It is also a method. In other words, the dissimilar metal other than copper is required to be a dissimilar metal film having performance suitable for the action of the etchant and the contact function, operation function selection, operation state selection, component mounting, and the like.

In addition, the present invention is such that a plurality of thickness conductors of at least two different metals (copper plating + dissimilar metal plating) and a plurality of thickness conductors stacked and stacked repeatedly are different from each other. May be independent of each other or may be partially overlapped with each other.
Further, in this circuit forming component, the dissimilar metal plating may be two types of dissimilar metal plating, for example, (nickel + gold).

  For example, when the conductive circuit is formed on the printed wiring board, the step of forming the first thickness conductor by pattern plating of a predetermined shape with a different metal other than panel copper plating + copper on the same flat and horizontal base material surface; A step of forming a second thickness conductor by pattern plating of a predetermined shape with a different metal other than copper, connected to the first thickness conductor, and a panel copper plating connected to the second thickness conductor + In the process of forming the third thickness conductor by pattern plating of a predetermined shape with a different metal other than copper, and the etching process using the pattern plating film of a different metal other than the first to third copper as an etching resist, A desired three-stage (type) of thick conductor is formed on the same base material surface.

Further, the number of stages can be increased by repeatedly stacking (panel copper plating + pattern plating with different metal other than copper having a predetermined shape) while shifting the position. Further, a plurality of conductive circuits can be formed in three dimensions on one side and both sides of the base surface of the printed wiring board.
The printed wiring board of the present application is provided with through-conduction holes (plating through-holes) and non-through-conduction holes that directly connect the double-sided outer layer conductors, and can form a three-dimensional circuit only on the component mounting surface side.
Further, the printed wiring board may form a three-dimensional circuit on one side or both sides of the outer layer surface of the multilayer wiring board having the inner layer circuit.

According to the present invention, a printed wiring board in which at least two or more thickness conductors having different steps are stacked and stacked on a flat same base material surface (copper plating + metal plating other than copper) is provided for each step circuit. There is no deviation, deformation, poor positional accuracy, conductor thickness variation, etc., and a high-quality, thin, small, and high-density contact part or operation part can be formed as a three-dimensional solid circuit. In addition, in the conventional synthetic resin molded product, it was impossible to reduce the thickness to 0.5 mm or less. However, the printed wiring board of the present invention can be a thin plate having a thickness of 0.05 mm. Wiring boards can be supplied to electronic component manufacturers and equipment manufacturers.
Since the dissimilar metal plating is used as a resist mask for etching without using a photosensitive dry film to withstand (copper plating and etching) of the present invention (copper plating mask and etching mask), etching of thick copper plating is possible. Can withstand quality and ensure quality reliability.

According to the present invention, in addition to the above-described effects, various configurations of (copper plating + different metal plating other than copper) in the same layer can be selected as necessary, and each configuration (copper plating + different metal plating) can be selected. The thickness can be freely set and a plurality of steps can be freely formed, so that it can be widely supplied to electronic component manufacturers and device manufacturers.
In addition, since different types of metal plating other than copper are used as resist masks for etching, different types of metal plating can be selected as necessary, and in addition to contact and operation functions, component mounting performance (wire bonding, bump connection, surface mounting) A highly reliable printed wiring board capable of simultaneously forming different metal plating other than copper for connection, discrete component connection, etc.) can be supplied at low cost.

  The combination of the printed wiring board implemented by the present invention with a functional component that allows a contact function, an operation function, a display function, etc. is an important condition. In addition, the performance of component mounting (wire bonding, bump connection, surface connection, Discrete component connection, etc.) and the arrangement and electrical connection of terminals (electrodes) for external connection are required.

Hereinafter, the manufacturing process of the printed wiring board of the present invention will be described with reference to FIGS.
First, the manufacturing process of the first half of the printed wiring board of Example 1 of this invention is demonstrated based on FIG.
FIG. 3A shows a copper clad laminate 2 (with a base material thickness of 0.1 mm) having copper foils 3a (9 μm, 18 μm, 35 μm) pasted on both sides.
It is possible to use a patterned copper-plated conductor (3) on both sides of the insulating base material by additive plating using an insulating base material coated with an emulsion adhesive, but the processing cost is high and the plating time is high. become longer.
In FIG. 3B, a predetermined portion of the copper-clad laminate 2 is drilled by an NC drilling machine or a laser machine to form a through hole 4a.

Next, as shown in FIG. 3 (c), panel copper plating (plating thickness 15 μm) is applied to the entire inner surface of the through hole 4a formed at a predetermined location and the entire surface of the copper foil 3a on both sides of the copper clad laminate 2. A through-conduction hole 4 (plating through hole) is formed by forming one panel copper plating conductor (3b).
Thereafter, as shown in FIG. 3 (d), a dry film is laminated on both surfaces of the copper clad laminate 2, and a pattern film mask having a predetermined pattern (image) is overlaid and exposed and developed to form a predetermined shape for dissimilar metal plating. A mask 6 is formed.
Next, as shown in FIG. 3 (e), the first panel copper-plated conductor (3b) formed on the copper-clad laminate 2 is subjected to pattern plating with a different metal other than copper, and a plating mask at a predetermined position. In addition to 6, a first dissimilar metal plating conductor (5a) having a predetermined shape is partially formed.

Then, after forming the first dissimilar metal plating conductor (5a) as shown in FIG. 3 (f), the dry film as the plating mask 6 is peeled off.
That is, in this example, the first dissimilar metal plating conductor (5a) having a predetermined shape was formed at a predetermined location on the through conduction hole 4 and the upper surface (in this example, a partial gold plating with a thickness of 0.5 μm by electrolytic gold plating). The first dissimilar metal plating conductor (5a) may be formed on both sides.
The first thick conductor made of (copper foil + panel copper plating + partial pattern plating with a different metal other than copper) is formed on the same flat base material surface in the steps so far. Therefore, in this example, the conductor thickness of the first thick conductor is about 30 μm to 35 μm.

The latter half of the printed wiring board manufacturing process according to the first embodiment of the present invention will be described with reference to FIG.
In FIG. 4G, as described above, [copper foil 3a + first panel copper-plated conductor (3b) + first dissimilar metal-plated conductor other than copper (5a)] becomes the first thickness conductor 7. After the plating process is performed, panel copper plating is performed on the entire surface of the through conduction hole 4 and the second panel copper plating conductor (3c). The thickness of the second panel electrolytic copper plating was 20 μm.
Next, as shown in FIG. 4 (h), a dry film is laminated on top of the second panel copper plating conductor (3c) of the copper clad laminate 2 in the same manner as in FIG. Then, a second plating mask 6 having a predetermined shape for the next metal plating is formed.

Thereafter, as shown in FIG. 4 (i), a portion of the second panel copper-plated conductor (3c) formed on the copper-clad laminate 2 is partially applied to a portion other than where the second plating mask 6 is formed. Then, pattern plating with a dissimilar metal (in this example, electrolytic gold plating with a thickness of 0.5 μm) is performed to form a second dissimilar metal plating conductor (5b) having a predetermined shape in addition to the plating mask 6.
Then, after forming a second dissimilar metal plating conductor (5b) as shown in FIG. 4 (j), the dry film as the plating mask 6 is peeled off.
Therefore, the thickness of the base conductor of the second thickness conductor 8 in the flat portion composed of [copper foil 3a + first panel copper plating conductor (3b) + second panel copper plating conductor (3c) + dissimilar metal plating conductor (5b)]. Was about 50 μm to 55 μm.

Thereafter, as shown in FIG. 4 (k), a first dissimilar metal plating conductor (5a) and a second dissimilar metal plating conductor (5b) partially formed in a predetermined shape at a predetermined portion of the copper clad laminate 2 Is used as a resist mask for etching, and unnecessary copper plating and copper foil are removed by a single etching process to form (metal copper + metal plating other than copper) having a predetermined shape (first thickness conductor 7 and second conductor The thick conductors 8) having two different thicknesses (two types) can be formed adjacent to or connected in steps.
If this dissimilar metal plating is 0.3 μm or more in thickness, it can withstand etching that dissolves and removes thick metal copper (eg, copper thickness of 50 μm or more) that is unstable and unbearable with a film mask, and can ensure quality reliability. Become.
In addition, after forming two or more types of thick conductors in a stepped manner by etching, the side surfaces (thickness side surfaces) of the step conductors and the exposed portions of the copper metal on the end surfaces of the through-conduction holes 4 are covered with different metal plating. Therefore, a third dissimilar metal plating may be performed.

This dissimilar metal plating other than copper performs partial pattern plating to form a desired thickness conductor, so that a metal containing any one of nickel, gold, silver and rhodium is good, and the dissimilar metal plating is made into a predetermined pattern. It is also a circuit formation method using the formed pattern plating as an etching resist.
Two-level (two types) or more thick conductors with different steps are three-dimensionally formed on only one side of the printed wiring board, and the opposite side (back side) is mainly composed of signal circuits and wiring circuits with no steps similar to normal wiring boards. A planar circuit may be formed.

4 (j), the second dissimilar metal plating conductor shown in FIG. 4 (j) is formed, and the dry film as the second dissimilar metal plating mask 6 is peeled off. g), a step of forming a plating mask for dissimilar metal plating shown in FIG. 4 (h), a step of forming a dissimilar metal plating conductor shown in FIG. 4 (i), and FIG. 4 (j). After the process of peeling the dry film as the plating mask shown is repeated and the base conductor of the third thickness conductor 9 is formed, unnecessary metal copper (copper plating and copper foil) shown in FIG. The third thick conductor 9 may be formed by processing. (Drawing is omitted)
Further, the steps shown in FIGS. 4 (g) to 4 (j) can be sequentially repeated to form a fourth thickness conductor, a fifth thickness conductor and a plurality of thickness conductors having different thicknesses in a staircase pattern or a staggered pattern. It is.

FIG. 1 is an enlarged cross-sectional view of a part of a printed wiring board having two steps (two types) of thick conductors according to Embodiment 1 of the present invention.
Through-conduction by forming panel first copper plating conductor (3b) by applying panel copper plating (plating thickness 15μm) to both sides of double-sided copper clad laminate 2 of substrate thickness 0.1mm and copper foil 3a (18μm) Hole 4 (plating through hole) is formed.

The outer conductors on both sides made of the first panel copper plating conductors (3b) on both sides of the printed wiring board are the through hole plating conductors on the inner wall of the through conduction hole 4 (plating through hole). The first panel copper plating conductor (3b) and the first dissimilar metal plating conductor (5a), and the second panel copper plating conductor (3c) and the second dissimilar metal plating conductor (5b) are electrically connected. The
However, in the second panel copper plating step shown in FIG. 4G, the dry film is used as the second panel copper plating mask, and the through-conduction holes 4 (through-hole holes) and the back surface of the printed wiring board are formed with the dry film. It is not necessary to form the second panel copper plating as a copper plating mask.

  The printed wiring board 1 according to the first embodiment of the present invention includes a first thickness conductor 7 composed of [copper foil 3a + first copper plating conductor (3b) + first dissimilar metal plating conductor 5a], 2 which is composed of [copper foil 3a + first copper-plated conductor (3b) + second copper-plated conductor (3c) + second dissimilar metal-plated conductor 5b] in the vicinity of or connected to the thickness conductor 7 of 1 The printed wiring board 1 is provided with a thick conductor different from the thick conductor 8 on the upper surface of the printed wiring board 1 in two steps.

The second thickness conductor 8 is [copper foil 3a + first copper plating conductor (3b) + first dissimilar metal plating conductor 5a + second copper plating conductor (3c) + second dissimilar metal plating conductor 5b]. It may be configured in a sand-etched state. (No drawing display)
Therefore, two or more types of conductors with different thicknesses in a (copper plating + different metal plating other than copper) configuration are aggregated in a small area and arranged in a staircase shape, and the contact function, operation function, or display on this area This is a printed wiring board 1 serving as a base on which functional components for performing functions and the like are mounted.

In other words, the printed wiring board 1 is formed in such a manner that at least two thick conductors having different thickness steps are adjacent or connected in a stepped manner of two steps, and the through-conduction holes 4 are arranged in the pattern area of the first thick conductor 7. An example is given.
The second thickness conductor 8 is formed close to the first thickness conductor 7, and this portion is electrically connected by a combination request with a functional component for causing a contact function, an operation function, a display function, and the like. However, the second thickness conductor 8 may be partially overlapped with the first thickness conductor 7, or the first thickness conductor 7 and the second thickness conductor 8 may be concentric. It can also be arranged eccentrically.

FIG. 2 is a cross-sectional view of a printed wiring board having three-stage thick conductors according to Example 2 of the present invention.
First, as shown in FIG. 2, the through-conduction hole 4 is arranged and formed in the area of the first thickness conductor 7 of the first embodiment of the present invention shown in FIG. 1, and the second thickness conductor 8 has the first thickness. Thickness conductors formed in the vicinity of the conductor 7 and having different steps are formed in the vicinity of two steps.

  In addition, [copper foil 3a + first copper plating conductor (3b) + second copper plating conductor (3c) + third copper plating conductor (3d) + third dissimilar metal plating conductor 5c] This is a printed wiring board 1 in which a third thick conductor 9 is formed by adjoining or concatenating thick conductors having different steps on a flat same base material surface (one surface in this example) in three steps.

The third thickness conductor 9 has a second thickness composed of [copper foil 3a + first copper plating conductor (3b) + second copper plating conductor (3c) + second dissimilar metal plating conductor 5b]. A panel copper plating is formed by overlapping the third copper plating conductor (3d) in addition to the upper surface of the conductor 8, and then the third dissimilar metal plating conductor 5c is partially overlapped with the above portion [ Copper foil 3a + first copper plating conductor (3b) + second copper plating conductor (3c) + second dissimilar metal plating conductor 5b + third copper plating conductor (3d) + third dissimilar metal plating conductor 5c] Are connected to each other, and the entire copper-clad laminate 2 is etched at a time to partially form the second thickness conductor 8 and the third thickness conductor 9 in the same pattern area in plan view. A stepped portion 19 is formed in contact with each other without any insulation gap and connected in a staircase pattern. A three-dimensional structure having a rough step becomes possible.
A three-dimensional structure in which complicated steps having different conductor thicknesses are freely (randomly) arranged on the XY plane in the same pattern area in plan view is possible.

  Further, a stepped portion 18 may be formed in which the first thickness conductor 7 and the second thickness conductor 8 are brought into contact with each other in the same pattern area, and the stepped portion 18 is connected stepwise. The thickness conductor 8 and the third thickness conductor 9 can be formed in a stepped portion consisting of three steps in which all the thickness conductors having different thicknesses are brought into contact with each other to form a stepped shape. That is, an inclined stepped recess can be formed. (No drawing display)

This dissimilar metal plating includes any one of nickel, gold, silver and rhodium as a partial pattern plating to form a desired thickness conductor, or if necessary, Ni plating-gold plating (Au), Ni plating- An additional plating process such as silver plating (Ag) can also be performed.
In addition to the contact function and operation function, various steps and connection lands (surfaces) can be selected to meet the required performance of mounted components (wire bonding, bump connection, surface connection, discrete component connection, etc.). An attached land, a wire-bonden ground, a bump connection land, etc.) can also be provided.

With reference to FIG. 5, the formation of functional units in a matrix on a large printed circuit board will be described in detail.
As shown in FIG. 5 (a), each individual side of the printed wiring board 1 of the present invention is as small as 3 to 5 mm from the viewpoint of equipment on the manufacturing process, work efficiency, variation in accuracy, and various problems in mounting components. As a large printed wiring board 20 in which a plurality of individual printed wiring boards 1 are combined into a matrix of a plurality of rows and a plurality of stages, the mounting parts are mounted on the large printed wiring board 20 and then cut vertically and horizontally. In many cases, it is divided into lines (X, Y) to form a plurality of individual mounting components or printed wiring board 1 as shown in FIG.

  In the large printed circuit board 20, the through conduction hole 4 or the non-through conduction hole is arranged at the intersection of the vertical and horizontal cutting lines (X, Y) to be divided and cut, and the vertical and horizontal cutting lines (X, In Y), an individual printed wiring board 1 shown in FIG. 5B is divided and cut by licing cut or laser cut.

The electrode terminals 12 for connecting the individual mounting components of the printed wiring board 1 of this example to the outside are arranged at the corners (corner portions) of the individual printed wiring boards 1 and the individual mounting components. It is also possible to form a large number of electrode terminals 12 by arranging the electrode terminals 12 on the outer periphery of the individual printed wiring boards 1 and the individual mounted components by being arranged on the cutting lines (X, Y). (No drawing display)
The electrode terminal 12 can also be used as a connection land (surfaced land, wire-bonden ground, bump connection land, etc.).

The individual printed wiring board 1 shown in FIG. 5B is formed with the first thickness conductor 7, the second thickness conductor 8, and the third thickness conductor 9 described above, and the first thickness conductor. A through-conduction hole 4 for electrically connecting circuit conductors on the front and back surfaces of the printed wiring board 1 is disposed in the central portion of 7.
The through-conduction hole 4 is filled with an insulator or the inside of the through-conduction hole 4 when the mounting of a mounting component that performs a contact function, a display function, an operation function, or the like is adversely affected. A non-through hole is closed with an object (plating conductor, metal conductor, conductive paste, etc.).
Further, the non-penetrating conduction hole in which one end surface of the through-conduction hole 4 is closed with a metal conductor may be closed at the upper end surface with a metal conductor, or the lower end surface of the through-conduction hole 4 may be closed with a metal conductor. A component element or a functional component can be mounted on the end face.
The second thickness conductor 8 and the third thickness conductor 9 are connected to individual electrode terminals 12 that connect the printed wiring board 1 and individual mounting components to the outside.

  A plurality of step circuits having different thicknesses of the printed wiring board of the present invention are formed in a small area where functional parts are mounted, and this area (area) is used for a contact function, a display function, an operation function, etc. Parts and terminals.

  For example, a movable contact piece (plate spring, disc spring, conductive film, conductive rubber, spring, etc.) is mounted on the top of this step circuit (three-dimensional circuit) with different conductor thickness, and it can be turned on and off with a small gap. -It can be a switch. This switch function has a contact function such as a multistage changeover selection switch and a multistage ON / OFF changeover selection switch by having a plurality of step circuits.

  Further, in the stepped circuit having the three-stage thickness conductor of FIG. 2 of the printed wiring board of the present invention, the first thickness conductor 7 is provided with the through-conduction hole 4 or the non-through-conduction hole, and the first thickness conductor 7 A functional component such as an LED or an indicator lamp is mounted in a low profile, and the second thick conductor 8 and the third thick conductor 9 are partially provided close to the first thick conductor 7 and electrically independent. Illumination increase, brightness increase, and transmission efficiency increase can be made by using two stepped portions connected in a staircase pattern superimposed on the reflector as a reflector, reflector, and light receiver.

In addition, a transparent / semi-transparent lens or a transparent material is attached to the upper part of the step circuit (three-dimensional circuit) that is gradually inclined from the center where the functional parts of this printed circuit board are mounted. It is.
Further, since the second thickness conductor 8 and the third thickness conductor 9 are formed in a flat portion, they can also be used as connection lands such as a wire-bonden ground and a bump connection land.

  Accordingly, in a plan view, a step formed by inclining the second thickness conductor 8 and the third thickness conductor 9 in a stepwise manner adjacent to or connected to the first thickness conductor 7 within the same minute pattern area. A portion can be formed and used for a reflector or a reflector. By forming the inclined stepped portion concentrically, eccentrically and concavely or convexly with the component mounting portion as the center, the component mounting and component connecting functions are improved.

  A plurality of inclined step circuits having different thicknesses of the printed wiring board of the present invention are formed in a small area. For example, the second thickness conductor 8 and the third thickness conductor 9 shown in FIG. Further, a plurality of independent circuits electrically separated by dividing the pattern of the same thickness conductor (8 or 9) formed concentrically and eccentrically into independent circuits disposed on the outer peripheral end face of the printed wiring board 1 By connecting to separate electrode terminals 12, a plurality of independent circuits can be formed in a minute area.

By pressing (pressing) one direction (a part) of a movable contact piece such as a flexible conductive film attached to the upper part of the inclined stepped circuit (three-dimensional circuit), the third contact of the second thickness conductor 8 and the third contact The one contact of the thick conductor 9 becomes conductive and the switch is turned on.
Therefore, a highly reliable functional component (push switch) having a contact function capable of selecting ON / OFF switching having a large number of directions can be formed.

1 is a cross-sectional view of a printed wiring board having two-stage thick conductors according to Embodiment 1 of the present invention. It is sectional drawing of the printed wiring board which has a 3 step | paragraph thick conductor of Example 2 of this invention. It is sectional drawing explaining the manufacturing process of the first half of the printed wiring board of this invention Example 1. FIG. It is sectional drawing explaining the manufacturing process of the second half of the printed wiring board of this invention Example 1. FIG. FIG. 5 is an explanatory diagram for forming functional portions in a matrix on a large printed wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Printed wiring board, 2 ... Copper clad laminated board, 3 ... Copper plating conductor, 4 ... Through-conduction hole, 5 ... Dissimilar metal plating conductor, 6 ... Plating mask, 7 ... 1st thickness conductor, 8 ... 2nd Thickness conductor, 9 ... third thickness conductor, 10 ... backside conductor 12 ... electrode terminal, 20 ... large printed wiring board.

Claims (1)

When a conductive circuit is formed on a printed wiring board, a step of partially forming a first dissimilar metal plating conductor on the first panel copper plating conductor formed on the copper clad laminate, and these conductors on the entire surface A step of partially forming a second dissimilar metal plating conductor on the second panel copper plating conductor to be coated, and etching the first dissimilar metal plating conductor and the second dissimilar metal plating conductor A circuit forming method comprising: forming at least two-stage thick conductors made of (metal plating other than copper + copper) on the same base material surface by a step of etching as a resist mask.

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