JP2512496B2 - How to attach masking material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for attaching a masking material to a masking portion on the solder side of a circuit board.

(Prior Art) When a plurality of electronic components are simultaneously soldered on a circuit board, the electronic components are placed on the circuit board and the electronic components are placed at predetermined positions on the circuit board by a cream solder welding furnace or a solder dip device. I try to solder all at once.

Then, on the solder side of the circuit board, a solder resist film is generally applied except for the solder land portion of the conductor circuit wiring pattern that electrically connects the electronic components, and the entire surface of the conductor circuit wiring pattern is soldered. To prevent the solder from adhering to the solder land portion. Therefore, the electronic component and the circuit wiring pattern are electrically connected by the solder attached to the solder land portion. Such a circuit board is mass-produced by a manufacturer that manufactures the circuit board itself, and then delivered to a manufacturer that mounts electronic components on the circuit board. Generally, the manufacturer of the circuit board itself and the manufacturer of the electronic component are often different.

However, some electronic components cannot be simultaneously soldered due to restrictions such as heat resistance, shape, weight, etc., and therefore need to be attached later. In addition, there are some parts such as a connector formed by plating a part of the circuit wiring pattern with gold, for which it is difficult for the solder to adhere during simultaneous soldering. In such a case, the mounting manufacturer, as shown in FIG.
Attach the solder masking adhesive tape 10 (masking material) to the area on the circuit board corresponding to the electronic component (solder land where the electronic component is attached) or the area where solder does not adhere, and solder is soldered simultaneously. In the case of, the other electronic components are simultaneously soldered and mounted, and then the adhesive masking tape 10 for solder masking is peeled off, and the electronic components are manually attached to the predetermined solder land portions for the retrofit electronic components. I try to solder.

(Problems to be Solved by the Invention) However, the above method has many problems as follows.

The work of cutting the solder masking tape 10 into a predetermined shape with scissors, adhering the solder masking tape 10 to a large number of places, and peeling the solder masking tape 10 is complicated, requires a large number of steps, and is costly. In particular, it is laborious to perform the above work on each of a large number of circuit boards.

It is necessary to attach solder masking tape 10 to many places, and accidents such as forgetting masking are likely to occur,
The yield is bad.

Although the solder masking tape 10 is cut into a required shape with scissors or the like, it is difficult to obtain the shape accuracy, and a masking error is likely to occur.

The sizing agent of the solder masking tape 10 remains on the circuit board, labor is required for removal, and when unwiping occurs, it hinders subsequent soldering work.

Therefore, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to enable efficient and rapid adhesion onto a circuit board, and also to remove a masking material after simultaneous soldering. It is to provide a method of attaching a masking material that can be efficiently performed.

(Means for Solving Problems) In order to solve the above problems, the present invention has the following configuration.

That is, it is attached to a plurality of masking portions on the solder surface side of the circuit board, and prevents solder attachment to the masking portion during simultaneous soldering work on the solder surface other than the masking portion, and after soldering work. In the method of attaching a masking material which is peeled off and exposes the masking portion, the masking material is formed on a screen of a screen frame with a cut pattern portion corresponding to the plurality of masking portions and a contact pattern portion connecting the cut pattern portions. The peelable masking ink is applied to the solder surface by printing using a printing plate described above, covering the plurality of masking sites and connecting the masking sites.

(Embodiment) A preferred embodiment of the present invention will be described in detail below together with its operation based on the accompanying drawings.

FIG. 1 shows a schematic sectional view of a printing plate 20 for forming a masking coating film used in the present invention.

22 is a screen frame, on which a screen 24 is stretched. A blanking pattern is formed on the screen 24 by a known method using a photoresist. That is, the photoresist applied on the screen 24 is exposed to ultraviolet rays through a mask to be exposed to light, and the photoresist in the non-exposed area is dissolved and removed, whereby a blank pattern according to the mask pattern is formed. 26 is the remaining photosensitive film, and 28 is the blank pattern.

Reference numeral 30 denotes a spacer, and a punching pattern 32 identical to the punching pattern 28 formed on the screen 24 is formed.

The spacer 30 is pattern-matched and is bonded to the lower surface of the screen 24, that is, the screen 24 on the side surface of the printing object by the adhesive 34. An adhesive tape may be used as the adhesive 34.

To form the blank pattern 32 on the spacer 30, a metal plate is used for the spacer, and the blank pattern 28 is formed on the screen 24.
The blank pattern 28 of the screen 24 can be easily formed by photoetching using the mask used for forming
The same punching pattern 32 can be formed.

The blank pattern 32 may be formed on the spacer 30 by pressing or the like. Of course spacer
The material of 30 is not limited to metal.

In the present invention, a coating film of printing ink is formed on the masking portion of the printing target to mask it.
That is, as shown in FIG. 1, the printing plate 20 is aligned and placed on a circuit board 36, which is an example of an object to be printed.
The solder mask ink 40 is printed on a predetermined portion of the circuit board 36 by 38, and a masking coating film as a masking material (hereinafter, also simply referred to as a coating film) on a plurality of masking portions.
42 forming at once at the same time.

A characteristic point of the present invention is that the coating film 42 formed on the circuit board 36 has masking portions A, B, C ..., H on the circuit board 36 as shown in FIG. Covering and connecting part between the masking parts A, B, C ..., H
The cut patterns 28 and 32 of the screen 24 and the spacer 30 are formed so as to be connected and connected by 44. That is, the punched patterns 28 and 32 are formed with a pattern portion 43 corresponding to each of the masking portions A, B, C ..., H and a contact pattern portion 45 corresponding to the contact portion 44 (FIG. 3). .

Therefore, by using the printing plate 20 and printing the peelable masking ink on the circuit board 36, a plurality of masking parts (a part for preventing solder from adhering at the time of simultaneous soldering) on the solder surface of the circuit board 36. ) A, B, C ...
., H, and masking parts A, B, C.
.. can be printed in a shape in which Hs are connected to each other to attach the coating film 42 as a masking material. Therefore, by mounting an electronic component (not shown) on the component mounting surface of the circuit board 36 and performing simultaneous soldering, the electronic component mounted by mounting the solder on the solder surface other than the masking portion is soldered. Together with the masking parts A, B, C ...
・ It is possible to prevent solder from adhering to H. Further, when the coating film 42 is peeled off from the circuit board 36 after the simultaneous soldering work, the coating film 42 is connected to the masking portions A, B, C, ... For coating 42
Can be continuously and efficiently peeled from the end portions of the masks, and the masking portions A, B, C, ..., H can be easily exposed. In particular, the coating film 42 is usually hardened by heat during soldering and becomes difficult to be peeled off from the circuit board 36.However, even in such a case, the coating film 42 covering the other masking portions can be contacted by peeling off only one portion. It can be continuously peeled off via the portion 44. Therefore, the electronic parts will be masked on the part A afterwards,
Workability is also good when mounting on B, C, ..., H by soldering. Further, as compared with the case of using the conventional masking tape, the adhesive agent of the masking tape does not remain on the circuit board when it is peeled off, so that the wiping operation is also unnecessary.

It is needless to say that the position, width, etc. of the connecting portion 44 are set so that the connecting portion 44 can be located on the circuit board 36 without any problem even if it is masked.

Also, if you can not set the contact section 44 as described above,
When it is inconvenient to connect a certain masking site to another masking site by the connecting portion 44, it is of course possible to form an independent coating film on these masking sites. Is.

The thickness of the coating film 42 is restricted by the thickness of the photosensitive film 26 and the thickness of the spacer 30. The thickness of the photosensitive film 26 is usually about 2 μm to 500 μm. Therefore, by selecting the thickness of the spacer 30, the coating film 42 having various thicknesses can be formed. As described above, the thickness of the coating film 42 may be set to have a strength that does not break when the coating film 42 is peeled off. Of course, the strength of the coating film 42 is
It depends on the thickness and the type of masking ink used.

The masking ink is required to form a peelable coating film that adheres to a printed material such as a circuit board with necessary adhesion. Further heat resistance is required for the solder masking ink.

In the above embodiments, the case where the masking coating film is formed on the circuit board has been described as an example, but it is also suitable for forming the masking coating film when the partial gold plating is applied to the lead frame for the semiconductor device, for example. Of course, it can be applied to.

Although the present invention has been variously described with reference to the preferred embodiments, the present invention is not limited to these embodiments.
Of course, many modifications can be made without departing from the spirit of the invention.

(Effects of the Invention) When the method for attaching a masking material according to the present invention is used, the masking material can be simultaneously printed at once in a single operation. Therefore, the masking tape is manually cut into a plurality of required masking areas one by one as in the conventional case. While there is no need to attach it, masking work can be done efficiently in a short time,
It is possible to prevent forgetting to mask the masking site. Further, since the work of attaching the masking material can be automated, the work efficiency can be further improved.
Further, since the blank pattern portion and the connecting pattern portion formed on the screen can be designed in advance with a required accuracy, masking can be performed more accurately and masking errors can be prevented as compared with the case where the masking tape is cut with scissors or the like.

Also, since the masking material is attached in a shape that connects the masking parts, when peeling off the masking material after simultaneous soldering, the masking material is cured by heat from the solder paste welding furnace or solder dip device and peeled off. Even if it becomes difficult, the masking material adhering to a plurality of masking portions can be continuously peeled off by peeling off one portion, and the peeling operation can be efficiently performed, which is a remarkable effect.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for forming a masking coating film on a circuit board using a printing plate, and FIG. 2 is an explanatory diagram of the formed masking coating film. FIG. 3 shows an explanatory diagram of the blanking pattern. FIG. 4 is an explanatory view showing a state of masking with a conventional solder masking adhesive tape. 10 …… Adhesive tape for masking, 20 …… Printing plate, 22 ……
Screen frame, 24 ... Screen, 26 ... Photosensitive film, 28 ...
… Drilling pattern, 30 …… Spacer, 32 …… Drilling pattern, 34 …… Adhesive, 36 …… Circuit board, 38 …… Squeegee, 40 …… Masking ink, 42 …… Coating, 44 …… Contact part.

Claims (1)

(57) [Claims] 1. A circuit board is attached to a plurality of masking sites on the solder side of the circuit board, and prevents solder from attaching to the masking site during simultaneous soldering work to the solder surface other than the masking site, and at the same time, soldering is performed. In a method of attaching a masking material that is peeled off after operation and exposes a masking portion, the masking material comprises a screen pattern of a screen frame, a pattern portion corresponding to the plurality of masking portions, and a contact pattern for connecting the pattern portions. Masking characterized by using a printing plate having a part formed thereon, and applying a peelable masking ink to the solder surface by printing in a shape covering a plurality of masking parts and connecting the masking parts. How to attach the material.