JP2903789B2 - Printed wiring board etching method and etching apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed wiring board used for various electronic devices and the like, and more particularly to an etching method and an etching apparatus therefor.

[0002]

2. Description of the Related Art In recent years, printed wiring boards, which are widely used in various electronic devices and the like, are required to have high reliability and high density wiring with the miniaturization and multifunctionality of electronic devices. It is becoming. Among the printed wiring board manufacturing processes, an etching process and a device to be used which directly correspond to realization of higher density and higher accuracy of wiring are particularly important.

A conventional method and an apparatus for etching a printed wiring board will be described below.

FIG. 2 schematically shows a conventional etching apparatus for a printed wiring board. In FIG. 2, 21 is a spray nozzle, 22 is a nozzle pipe for the upper surface, 23 is a nozzle pipe for the lower surface, 24 is a pressure gauge for the upper surface, 25 is a pressure gauge for the lower surface, 26 is a pressure adjustment valve for the upper surface, and 27 is a pressure for the lower surface. An adjustment valve, 28 is an upper surface spray pump, 29 is a lower surface spray pump, 30 is a feed roller, 31 is an etching booth, and 32 is a printed wiring board.

[0005] A method of etching a printed wiring board in the etching apparatus configured as described above will be described below.

First, a printed wiring board 32 in which an etching resist is formed on a copper-clad laminate (not shown) cut to a predetermined size by a screen printing method, a photographic method, or the like, is placed in an etching booth 31 in a traveling direction. Alternatively, the substrate is conveyed at a predetermined speed on the feed roller 30 between the upper surface nozzle pipe 22 and the lower surface nozzle pipe 23 piped at a predetermined angle, and an etching solution such as cupric chloride is applied to the upper and lower surfaces of the printed wiring board 32. Etching is performed by spraying from a spray nozzle 1. At this time, the upper surface nozzle pipe 22 and the lower surface nozzle pipe 23 may be oscillated (oscillated) at an angle of 45 to 60 ° with respect to the traveling direction of the printed wiring board 32. After that, a circuit pattern of the printed wiring board is formed by performing water washing, etching resist stripping, and the like.

[0007]

However, in the above-mentioned conventional structure, there is a large difference in the etching speed between the upper surface and the lower surface of the printed wiring board, and the etching liquid stays at the center of the printed wiring board on the upper surface of the printed wiring board. The etchant immediately flows down in the outer peripheral portion of the printed wiring board and does not stay, so there is a large difference in circuit pattern finish accuracy between the central portion of the upper printed wiring board and the outer peripheral portion of the printed wiring board. It is difficult to perform high-precision and uniform etching on the upper and lower surfaces of the wiring board, and there is a problem that the yield of the printed wiring board manufacturing process is significantly deteriorated.

In order to solve these problems, the printed wiring board is inclined or vertical in the etching step,
In some cases, a method has been devised and implemented in which the etchant is spouted from a spray nozzle in the side direction to eliminate the stagnation of the etchant. Therefore, there is a problem that productivity of printed wiring board manufacturing is remarkably deteriorated and manufacturing cost is increased.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and makes the finishing accuracy of the circuit pattern on the upper and lower surfaces of the printed wiring board high and uniform without reducing the productivity in the etching step of the printed wiring board. The purpose is to produce high-density and high-precision printed wiring boards with good yield.

[0010]

SUMMARY OF THE INVENTION To achieve this object, the present invention provides a method for supplying a new etchant to a non-circuit pattern portion, wherein the desired circuit pattern portion is convex and the non-circuit pattern portion is concave. An etching apparatus for a printed wiring board, comprising: an etching type having at least one groove and at least one waste liquid groove for an etching liquid; and an etching liquid storage tank connected to the new liquid supply groove and the waste liquid groove of the etching type via a pipe. The copper-clad laminate is pressed by pressing the convex circuit pattern portion onto the copper-clad laminate, and adjusting the supply pressure and supply amount of the new solution for the concave non-circuit pattern portion and the etching solution supplied from the supply groove. Of copper foil is etched.

[0011]

With this configuration, the pressure and amount in the supply groove of the etchant can be adjusted at different positions on the printed wiring board in accordance with the area of the copper foil to be etched and the amount of etching, and the etching rate can be made uniform. It is possible to make adjustments, and it is possible to form the circuit pattern finish on the upper and lower surfaces of the printed wiring board, the central portion, and the outer peripheral portion with high accuracy and uniformity.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1A and 1B are schematic views of a printed wiring board etching apparatus according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an etching apparatus made of a material having resistance to a cupric chloride etchant, for example, vinyl chloride, butyl rubber, polyethylene, titanium, or the like; and 2, a desired circuit pattern is formed in a convex shape. 3 is a non-circuit pattern portion formed in a concave shape, 4 is a new liquid supply groove for an etching solution formed in the non-circuit pattern portion, and 5 is an etching solution formed in the non-circuit pattern portion. 6, an etchant storage tank, 7 a supply pump for the etchant, 8 a supply pipe connecting the etchant storage tank 6 with the supply pump 7 and the new solution supply groove 4, 9 an etchant storage tank and a waste liquid A waste liquid pipe connecting the grooves, 10 is an etching booth, 11 is a pressure / flow control valve installed on the supply pipe 8, 12 is a copper-clad laminate, 13 is copper foil, and 14 is copper foil. A through hole formed in the printed wiring board.

A method for etching a printed wiring board in the etching apparatus configured as described above will be described below.

First, a copper-clad laminate 12 cut into a predetermined size and subjected to hole processing and through-hole plating is placed in an etching booth 1, and a convex circuit pattern portion 2 of an etching apparatus 1 is placed from above and below. Crimping with. Next, an etching solution of cupric chloride is supplied from a new liquid supply groove 4 formed in the concave non-circuit pattern portion 3 through the supply pump 7 and the supply pipe 8 in a state of being pressed, and the copper-clad laminate is formed. The copper foil 13 of the non-circuit pattern portion 3 is etched by flowing out into the concave portion of the non-circuit pattern portion 3 on the substrate 12. At this time, the pressure / flow rate adjusting valve 1 depends on the copper foil area to be etched.
Step 1 adjusts the supply pressure and supply flow rate of the etching solution. That is, when the copper foil of the concave non-circuit pattern portion 3 has a large etching area, the flow rate of the etching liquid is large, and when the etching area is small, the flow rate of the etching liquid is small. After etching the copper foil 13, the deteriorated etching solution flows into the waste solution groove 5 formed in the non-circuit pattern portion 3, and passes through the waste solution pipe 9 to the etching solution storage layer 6.
to go into.

The deteriorated etching solution is detected and analyzed for temperature, specific gravity, hydrochloric acid concentration, and the like in the etching solution storage layer 6 by a sensor installed in a controller or the like, and water, hydrochloric acid, and hydrogen peroxide are removed as necessary. Replenishment is performed to maintain the predetermined state of the cupric chloride etching solution. The etching liquid adjusted to a predetermined state can be constantly supplied to the concave non-circuit pattern section 3 through the supply pump 7 and the supply pipe 8 to constantly supply a constant adjusted new liquid. Also,
Supply pipe 8 and waste liquid pipe 9 to concave non-circuit pattern portion 3
It is also possible to configure the etching apparatus 1 by increasing or decreasing the number in advance. In this case, the pressure / flow rate adjusting valve 11 may not be necessary.

As described above, according to this embodiment, a circuit pattern can be formed irrespective of the upper and lower surfaces of the printed wiring board, the center and outer peripheral portions of the printed wiring board, the etching area, and the like, as compared with the conventional example. The width of the circuit pattern after etching by the etching method was 50 to 100 μm, which varied between the upper and lower surfaces of the printed wiring board and the central part and the outer peripheral part of the printed wiring board, but was significantly reduced to 10 to 20 μm in this embodiment. Results were obtained. Furthermore, short-circuiting or disconnection of the circuit pattern due to the etching resist forming process becomes unnecessary, such as eliminating the need for filling the through holes and forming and removing the etching resist used in the production of double-sided printed wiring boards and multilayer printed wiring boards. Defects can be suppressed.

Although the printed wiring board is a double-sided printed wiring board in the embodiment of the present invention, the printed wiring board may be a single-sided printed wiring board or a multilayer printed wiring board, and the etching solution is cupric chloride. However, it goes without saying that the etchant may be an alkaline etchant such as ferric chloride or ammonia.

[0018]

As described above, the present invention flows from the concave non-circuit pattern portion of the etching apparatus due to the difference between the upper and lower surfaces of the printed wiring board, the center portion and the outer peripheral portion of the printed wiring board, and the copper foil etching area. Etching solution pressure
By adjusting the flow rate, the circuit pattern finish can be made highly accurate and uniform, and high-density, high-precision printed wiring boards can be produced with good yield. This eliminates the need for filling through holes and forming and stripping etching resists, improving the process yield by eliminating defects such as short-circuits and breaks in circuit patterns caused by the etching resist formation process, and manufacturing printed wiring boards. Reduction of lead time, filling ink,
An excellent method and apparatus for etching a printed wiring board, which can reduce materials such as an etching resist ink, can be realized.

[Brief description of the drawings]

FIGS. 1A and 1B are a schematic view of a printed wiring board etching apparatus and a perspective view of a main part according to an embodiment of the present invention.

FIG. 2 is a schematic view of a conventional printed wiring board etching apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Etching apparatus 2 Circuit pattern part 3 Non-circuit pattern part 4 New liquid supply groove 5 Waste liquid groove 6 Etching liquid storage tank 7 Supply pump 8 Supply pipe 9 Waste liquid pipe 10 Etching booth 11 Pressure / flow control valve 12 Copper clad laminate 13 Copper foil 14 Through hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H05K 3/06 C23F 1/00

Claims (3)

(57) [Claims] 1. An etching method in which a desired circuit pattern portion is convex and a non-circuit pattern is concave, and a convex circuit pattern portion is press-bonded to a copper-clad laminate to form a new concave non-circuit pattern portion. A method for etching a printed wiring board, wherein a copper foil of a copper-clad laminate is etched by adjusting a supply pressure and a supply amount of an etchant supplied from a liquid supply groove. 2. An etching method in which a desired circuit pattern portion has a convex shape and a non-circuit pattern portion has a concave shape, and the non-circuit pattern portion has at least one new liquid supply groove for an etching solution and at least one waste liquid groove for an etching solution. An apparatus for etching a printed wiring board, comprising: a mold; and an etching solution storage tank connected to the new solution supply groove and the waste solution groove of the etching type via a pipe. 3. The apparatus for etching a printed wiring board according to claim 2, further comprising means for adjusting a supply pressure and a supply flow rate of the etching solution in a flow path between the etching solution storage tank and the new solution supply groove.