JPH0436146Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The disclosed technology belongs to the field of technology for improving the accuracy of printed wiring used in electronic devices.

Therefore, this idea is based on a printed circuit board in which a thin conductor of copper foil is printed on the surface of a plate-shaped insulating base material such as a phenolic resin laminate of a predetermined size, and a circuit pattern is coated with an insulating solder resist. This is an invention related to the alignment mark structure, and in particular, in the process of printing copper foil on the surface of an insulating base material to form a circuit pattern, a alignment mark is formed on one circular circuit pattern side, and the alignment mark is covered concentrically with that. The other alignment mark on the solder resist side has a cover area within the set tolerance range, and the exposure of the copper foil due to the alignment mark deviation can be eliminated. This is an idea related to the mark structure.

<Prior Art> As is well known, in printed wiring used in electronic devices, the surface of the conductive circuit itself is insulated.For example, as shown in FIG. The circuit pattern 2 is formed as having a circuit pattern 2 of
As shown in Publications Nos. 55-103555, 57-43494, and 49-37159, the solder resist is coated through a resist printing plate, and at that time, the alignment of the circuit pattern 2 and the solder resist is This is done at the alignment position for manufacturing (not on the circuit side), and at this time, in order to inspect the entire surface for misalignment between the two, for example, as shown in the device of Japanese Utility Model Application No. 52-117257, , alignment marks 4, 4 are formed diagonally.

Note that since the lands 3 and alignment marks 4 are processed simultaneously by one etching plate, there is, of course, a correlation in position.

The alignment marks 4, 4 are ring-shaped in any conventional manner, and as shown in FIGS. The side alignment mark 5 is formed by forming a copper foil 8 on a base material 17 on a ring portion 6 and a pair of opposing fan-shaped portions 7, 7 integral with the ring portion 6, and etching the copper foil on the other portions. The alignment marks formed from the removed portion 9 and formed on the solder resist side when coating the printed wiring board with the solder resist are the opposing fan-shaped parts 11, 11, the circular part 12 on the inside thereof, and the ring on the outside thereof. formed from a portion 13 and an outer portion 14;
A solder resist 15 is applied to the outer portion 14, the circular portion 12, and the fan-shaped portions 11, 11, and the other portions are not coated.

Then, the alignment mark 10 on the solder resist side is superimposed on the alignment mark 5 on the circuit pattern 2 side to form the alignment mark 4, and when soldering lead wires etc. to the land 3, the alignment mark 10 on the solder resist side If the solder resist 15 applied part covers the copper foil 8 of the alignment mark 5 on the lower circuit pattern 2 side, solder will not adhere, but conversely the solder resist 15 will not be applied. Since the lower copper foil 8 is exposed in the parts such as the ring portion 13 that are not covered, the solder 16 is deposited on the copper foil 8 during automatic soldering, as shown in FIGS. 13 and 14, for example. Also, as shown in FIG. 15, if the alignment marks 5 and 10 are misaligned, the misaligned copper foil 8 will be exposed in the same way as described above, and during automatic soldering, the exposed portion of the copper foil 8 will be exposed. Solder 16 is attached.

<Problem to be solved by the invention> Furthermore, as shown in FIG. 13, even if the alignment mark 10 on the solder resist side is formed on the alignment mark 5 by overlapping, If the fan-shaped part 11 coated with the solder resist 15 and the inner circular part 12 are not overlapped on the copper foil 8 part of the mark 5, it will be difficult to solder the lead wires etc. to the land 3 in a dip bath or the like. If the solder 16 becomes dango-like or balloon-like,
(In actual products, the solder 16 is attached to lands with a large diameter of 3 to 5 mm, but in the case of alignment marks, the exposed part of the copper foil 8 is small, about 1 mm, and has a diameter of 3 to 5 mm.) The solder 16, which is as large as 1 to 2 mm, expands due to surface tension and takes on the shape of a dumpling or a balloon, and the force of gravity acts heavily.) When an external impact is applied, the solder 16 falls from the printed wiring board 1. This has the drawback that it can get between the lead wires of the IC or into the alignment mark 4, deteriorating the conductive properties and impairing reliability.

The purpose of this invention is to solve the problem of the ring-shaped alignment mark based on the above-mentioned conventional technology as a technical problem, and when the degree of misalignment between the circuit pattern and the solder resist is within the permissible range, the copper foil of the alignment mark etc. It is an object of the present invention to provide an excellent alignment mark structure for a printed wiring board that can prevent solder from adhering to the conductive parts of the printed wiring board, thereby benefiting the field of circuit technology application in the electrical industry.

<Means for solving the problem> In order to solve the above-mentioned problem, the structure of this invention, which is based on the above-mentioned utility model registration claims, is based on a circuit pattern of a printed circuit on a base material of a predetermined size. The circuit pattern side alignment mark includes a circular circuit pattern side alignment mark of a predetermined size to be formed, and a circular solder resist side alignment mark formed together with the solder resist covering at least a part of the circuit pattern. An alignment mark structure of a printed wiring board for aligning the circuit pattern and the solder resist by overlapping the alignment mark on the solder resist side with the mark, the alignment mark on the solder resist side being The center is formed at a position overlapping with the center of the alignment mark on the circuit pattern side, and the diameter of the alignment mark on the solder resist side is larger than the diameter of the alignment mark on the circuit pattern side to allow for a misalignment between the two. This is a printed wiring board registration mark structure characterized by being twice as large as the original size.

<Function> Then, a predetermined circuit pattern is formed on the printed wiring board by etching or the like, and at the time of forming the circuit pattern, a circular alignment mark of a predetermined size is formed on the circuit pattern side, and then the solder resist is attached to the circuit pattern. When coating the circuit pattern side, a circular alignment mark on the solder resist side is formed in a size that concentrically covers the alignment mark on the circuit pattern side, and the alignment mark on the solder resist side and the alignment mark body on the circuit pattern side are formed. With regard to the size of When soldering, make sure that no solder adheres to the alignment mark, and avoid problems caused by solder adhering there, such as shorts caused by adhering solder falling into the circuit, and avoid deviations beyond the allowable range. In this case, we have taken a technical measure that allows us to visually determine whether the misalignment is good or bad by observing the adhesion of solder to the copper foil.

<Example> Next, an example of this invention will be described below based on the drawings of FIGS. 1 to 9.

Note that the same parts as in the drawings from FIG. 10 onwards will be described using the same reference numerals.

In the embodiment shown in FIG. 1, a predetermined circuit pattern 2 is formed on one side surface of a plate-shaped base material 17 of a predetermined size and laminated with phenolic resin by etching treatment, as in the conventional embodiment, and a printed wiring board 1' is formed. The circuit pattern 2 is formed with soldering lands 3, 3, . Alignment marks 4', 4' are formed.

As shown in FIGS. 2 to 5, when forming the circuit pattern 2, the alignment mark 5' on the circuit pattern side is
are formed in circular shapes of a predetermined size using copper foil 8, and a solder resist 15 is applied to the printed wiring board 1' using a resist printing plate except for the lands 3, 3, . . . .

When applying the solder resist 15, as shown in FIGS. 6 to 9, an alignment mark 10' having a set size larger than the alignment mark 5' of the copper foil 8 on the circuit pattern side is applied to the surrounding solder resist 15. It has a circular solder resist 15 on the inside with a ring-shaped uncoated portion 18 interposed therebetween, and is formed into a circular shape so as to be concentric with the alignment mark 5'.

Then, the registration mark 5' shown in FIGS. 2 and 3 and the registration mark 10' shown in FIGS. 4 and 5 are superimposed upon printing, and the registration mark 4' shown in FIGS. 6 and 7 forms the center of the gist of this invention. The alignment mark 10' is integrally formed with the alignment mark 5' so as to cover the alignment mark 5' in a concentric manner without shifting from each other, as shown in FIGS. 6 and 7. Covered by the alignment mark 10', the copper foil 8 is placed in a kind of insulating state.

In the above structure, if there is a deviation in the overlapping of the alignment mark 5' and the alignment mark 10' (center line deviation), there is a tolerance range for the deviation, and it is effectively 6,7
As shown in the figure, alignment mark 5' is aligned with alignment mark 1.
If the solder alignment mark 5' is not exposed from the circular part 0', the solder alignment mark 5' will not adhere to the copper foil 8.

Therefore, the range of the deviation is the alignment mark 1
It has been found that the size should be smaller than half of the diameter difference between 0' and 5', and the alignment mark 4' is designed in this way.

In other words, alignment mark 1 on the solder resist side
The diameter of 0' is made larger than that of alignment mark 5' on the circuit pattern side by twice the allowable amount of deviation between the two.

Thus, as shown in FIGS. 6 and 7 at the alignment mark 4', if the alignment mark 5' of the copper foil 8 is not exposed from the alignment mark 10', that is, if there is no misalignment between the two, the land 3 When soldering lead wires, etc., at the dowel marks 4', 4', the solder becomes bumpy and falls off due to external impact, causing the circuit pattern 2 of the printed wiring board 1' to deteriorate. There is no need to re-apply the solder resist 15 on the alignment mark 4' without impairing reliability by entering or shooting the solder resist 15.

In addition, as shown in FIGS. 8 and 9, alignment mark bodies 5',
Even if there is a deviation in 10', if it is within an allowable range, the copper foil 8 will be covered with the solder resist 15 and the solder 16 will not adhere, and the same function as described above will occur.

If there is a deviation that exceeds the allowable range, the solder 16 will adhere to the alignment mark 5', so that it can be sufficiently confirmed visually, making it possible to judge whether the deviation is good or bad, and making it unnecessary to check the entire board.

Therefore, when inspecting the deviation between the circuit pattern 2 and the solder resist using the alignment mark 4', it is sufficient to check with the naked eye whether there is solder to the alignment mark 5', and there is no need to measure the deviation using a microscope or the like. .

It goes without saying that the embodiments of this invention are not limited to the above-mentioned embodiments.

<Effects of the invention> As described above, according to this invention, the alignment mark on the solder resist side that covers the circular alignment mark on the copper foil on the circuit pattern side is formed in a circular shape, and the alignment mark is twice the allowable range of deviation between the two. The latter was increased by the size of the solder mask, and only when the degree of misalignment of the solder resist with respect to the circuit pattern exceeded the allowable range, solder adhered to the alignment mark on the circuit pattern side, so the allowable range was increased. As long as the circuit pattern and solder resist are not misaligned, solder will not adhere to the alignment mark on the circuit pattern side, and unlike conventional methods, the adhering solder may fall off the printed wiring board due to impact, etc., and cause damage between the lead wires, etc. It is possible to improve the reliability of an electronic device made up of this printed wiring board without causing any problems, and the quality of the electronic device can also be improved, which is an excellent effect.

In addition, it is possible to check whether the degree of misalignment is within the allowable range by visually checking only the presence or absence of solder adhesion on the alignment marks on the circuit pattern side, and it is possible to check whether the degree of deviation is within the allowable range by visually checking the presence or absence of solder adhesion on the alignment marks on the circuit pattern side. It has the excellent effect of being able to easily inspect the misalignment between the copper foil and the solder resist without requiring skill and high cost inspections such as measuring the misalignment of parts with a microscope, etc. Ru.

By making the diameter of the alignment mark on the solder resist side twice as large as the allowable misalignment range than that of the alignment mark on the circuit side, the former can sufficiently cover the latter, allowing the solder to reach the copper foil on the latter. It has the effect of preventing adhesion.

[Brief explanation of the drawing]

Figures 1 to 9 are explanatory diagrams of one embodiment of this invention, in which Figure 1 is a plan view of a printed wiring board, Figure 2 is a plan view of copper foil, and Figure 3 is a longitudinal cross-sectional view of copper foil. , Fig. 4 is a plan view of the solder resist, Fig. 5 is a longitudinal sectional view of the solder resist, Fig. 6 is a plan view of the alignment mark, Fig. 7 is a longitudinal sectional view of the same, and Fig. 8 is a vertical sectional view of the solder resist. Plan view of an example of alignment mark when
Figure 10 is a longitudinal sectional view of the same, Figure 10 and the following are explanatory diagrams based on the prior art, Figure 10 is a plan view of a printed wiring board, Figure 11 is an enlarged plan view of a copper foil alignment mark,
Fig. 12 is an enlarged plan view of the alignment mark on the solder resist, Fig. 13 is a plan view of one embodiment of the alignment mark, Fig. 14 is a vertical cross-sectional view of the same, and Fig. 15 is a plan view when the alignment mark is misaligned. be. 17... Base material, 2... Circuit pattern, 15...
Solder resist, 5'... alignment mark on circuit pattern side, 10'... alignment mark on solder resist side, 1'... printed wiring board.

Claims (1)

[Scope of utility model registration request] An alignment mark on the side of a circular circuit pattern of a predetermined size formed on a base material of a predetermined size together with a circuit pattern of a printed wiring circuit, and a circular solder resist formed together with a solder resist covering at least a portion of the circuit pattern. an alignment mark on a printed wiring board for aligning the circuit pattern and the solder resist by overlapping the alignment mark on the circuit pattern side with the alignment mark on the solder resist side; In the above, the alignment mark on the solder resist side is formed at a position where its center overlaps the center of the alignment mark on the circuit pattern side, and the diameter of the alignment mark on the solder resist side is the diameter of the alignment mark on the circuit pattern side. An alignment mark structure for a printed wiring board, characterized in that the alignment mark is twice as large as the allowable amount of misalignment between the two.