JP3413874B2 - Printed wiring board - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring having a screen mark for aligning a screen mask for applying solder and a component mounting mark for aligning components to be mounted. It is about boards.

[0002]

2. Description of the Related Art When mounting a surface mount component on a wiring pattern formed on the surface of a substrate, it is necessary to apply solder to the wiring pattern to be connected in advance. The mounting of components on a printed wiring board has become more and more dense in recent years, and there is a demand for improvement of alignment accuracy in solder coating, optimization of coating amount, and high accuracy of alignment in component mounting. Generally, in order to apply solder to a printed wiring board, a screen printing method using a screen mask in which a desired portion is open is used.

5A and 5B are views for explaining a conventional printed wiring board. FIG. 5A is a plan view and FIG. 5B is an enlarged view of a component mounting mark. That is, the printed wiring board 1 is composed of the substrate 10 having the wiring pattern region 2, the screen mark 3 and the component mounting mark 4 provided outside the wiring pattern region 2 on the surface of the substrate 10. .
The component mounting mark 4 is used for alignment when mounting a component (not shown) on a wiring pattern (not shown) provided in the wiring pattern region 2, and FIG.
As shown in FIG. 5, a resist film 5 is coated around a square land 41, for example, and a resist opening 4a having a predetermined shape is provided in the central portion. The image of the component mounting mark 4 is read by an optical reading device such as a CCD, and image processing is performed to detect the positional deviation of the printed wiring board 1 to mount the component at an accurate position.

FIG. 6 is an enlarged view of the screen mark 3, which is composed of, for example, four fan shapes. Each fan shape is formed by a resist opening 3a in which the resist film 5 covering the land 31 is opened, and each fan shape is aligned with the opening provided in the screen mask.

7 to 8 are sectional views for explaining the alignment of the screen mask. First, as shown in FIG. 7, the screen mark 3 provided on the surface of the substrate 10
The screen mask 30 or the substrate 10 is arranged so that the resist opening 3a and the screen opening 30a of the screen mask 30 are aligned with each other. That is,
The screen openings 30a and the resist openings 3a of the screen marks 3 are provided so as to correspond in size to each other, and the registration is performed so that the resist openings 3a can be seen through the screen openings 30a. . Next, as shown in FIG. 8, the screen opening 30a of the screen opening 30a and the resist opening 3a are aligned with each other by bringing the screen opening 30 into close contact with the printed wiring board 1. In this state, the solder 6 is scraped from the screen mask 30 to remove the resist opening 3a.
Solder 6 is applied to. At this time, the solder 6 is accurately applied on the wiring pattern (not shown) provided on the surface of the substrate 10.

As described above, since the screen opening 30a and the resist opening 3a are aligned with each other, the solder 6 is applied to the surface of the screen mark 3 when screen printing is performed. Therefore, the resist opening 3a is filled with the solder 6, and the screen mark 3 cannot be used also as the component mounting mark 4. In other words, even when the image of the screen mark 3 to which the solder 6 is applied is captured by the optical reading device, the boundary line becomes unclear due to the swelling of the solder 6 filled in the resist opening 3a, and highly accurate alignment is achieved. Cannot handle. Therefore, the screen mark 3 and the component mounting mark 4 are provided separately to cope with this.

[0007]

In such a printed wiring board, however, by providing the screen mark and the component mounting mark separately outside the wiring pattern area, the area required for the mark installation increases. Will be invited. As described above, the increase of the installation area of the mark hinders the expansion of the wiring pattern area of the substrate, which is a problem in designing the printed wiring board. Further, in order to cope with fine-pitch component mounting and high-density mounting, highly accurate alignment is necessary, but it is difficult to deal with such component mounting marks.

[0008]

The present invention is a printed wiring board made to solve the above problems. That is, this printed wiring board has a screen mark for aligning a screen mask for applying solder on the wiring pattern provided on the surface of the substrate, and a component mounted through the solder applied on the wiring pattern. With a component mounting mark for aligning the
Provide the component mounting mark inside the screen mark
Together with screen mark and component mounting mark
Open the same resist film that covers the land as
The outer shape of each is constituted by. Further, it is also a printed wiring board in which the component mounting mark is formed of a substantially parallelogram, and each diagonal line of the substantially parallelogram is used as a reference axis for alignment.

[0009]

By providing the component mounting mark provided on the surface of the substrate inside the screen mark used for aligning the screen mask, both marks can be installed only in the area required for installing the screen mark. further,
Run as mark for screen and mark for mounting components
By opening the same resist film that covers the
By configuring the shape, a screen is formed when the resist film is formed.
Mark and component mounting mark can be formed simultaneously,
Relative position of screen mark and component mounting mark
The positional relationship can be made accurate. Moreover, the resist film
By applying solder to the land exposed from the opening of
The amount of solder applied can be monitored. Further, by using the component mounting mark formed of a substantially parallelogram and using each diagonal line thereof as the reference axis for the alignment, it becomes easy to determine the alignment reference based on the component mounting mark.

[0010]

Embodiments of the printed wiring board of the present invention will be described below with reference to the drawings. 1A and 1B are views for explaining a printed wiring board of the present invention. FIG. 1A is a plan view and FIG. 1B is an enlarged view of a mark portion. That is, the printed wiring board 1 is provided outside the wiring pattern area 2 provided on the surface of the substrate 10.
The screen mark 3 and the component mounting mark 4 are provided, and these are provided at one place.

The screen mark 3 is for aligning a screen mask (see FIG. 7) for applying solder onto a wiring pattern (not shown) provided in the wiring pattern region 2. Further, the component mounting mark 4 is for aligning the components to be mounted on the wiring pattern through the applied solder. In the printed wiring board 1 of the present invention, as shown in FIG. 1B, the component mounting mark 4 is provided inside the screen mark 3.
Is provided.

For example, the screen mark 3 is formed by covering the four lands 31 with a resist film 5 to form a fan-shaped resist opening 3a. The component mounting mark is aligned with the center position O. 4 are arranged. The component mounting mark 4 has a resist film 5 around the land 41.
It is provided with a substantially parallelogram-shaped resist opening 4a, and the diagonal lines of the substantially parallelogram are used as reference axes X and Y for alignment. That is, the center position O ′, which is the intersection of the reference axes X and Y, is arranged so as to coincide with the center position O of the screen mark 3.

Next, the alignment using the screen mark 3 and the component mounting mark 4 will be described. First, the alignment of the screen mask using the screen mark 3 is the same as in the conventional case, and as shown in FIG.
The position a is aligned with the resist opening 3a of the screen mark 3. Thereafter, as shown in FIG. 8, the screen mask 30 is closely attached onto the printed wiring board 1 and solder is applied.

FIG. 2 is an enlarged view of the mark portion after solder application. That is, since the size of the fan-shaped resist opening 3a of the screen mark 3 is equal to the size of the screen opening 30a of the screen mask 30 shown in FIGS. 7 and 8, the solder 6 ( The shaded area in the figure) will be filled. In order to monitor the amount of the applied solder 6, the same screen mask 30 may be used to apply the solder 6 in the substantially parallelogram-shaped resist opening 4a of the component mounting mark 4. In addition,
As the solder 6 for the monitor, the component mounting mark 4 is used.
By coating the inside of the resist opening 4a, it does not hinder the determination of the boundary line of the component mounting mark 4.

Next, the alignment using the component mounting mark 4 will be described. That is, to mount a component on the printed wiring board 1, the printed wiring board 1 is positioned on a mounter (not shown), and then the component is placed on the wiring pattern coated with the solder 6. At this time, it is necessary to correct the positional deviation of the printed wiring board 1 to be placed on the mounter and mount the component at an accurate position on the printed wiring board 1. Therefore, the image of the component mounting mark 4 provided on the printed wiring board 1 is captured by an optical reading device such as a CCD.

FIG. 3 is a diagram showing this captured image. The captured image shows the substantially parallelogram-shaped resist opening 4a of the component mounting mark 4 and the applied solder 6. After binarizing the captured image, for example, the substantially parallelogram of the resist opening 4a is recognized by pattern matching or the like. Then, the reference lines X and Y and the center position O ′ are obtained by obtaining each diagonal line of the substantially parallelogram.

Since the component mounting mark 4 is formed of a substantially parallelogram, the reference lines X and Y and the center position O'can be easily and accurately obtained from the captured image. A deviation amount between the reference lines X and Y and the center position O ′ and a preset reference position on the screen is obtained, and the printed wiring board 1 is moved so as to correct the deviation amount and alignment is performed. . As a result, the component can be mounted at an accurate position on the printed wiring board 1. In the case of high-density mounting, the component mounting mark 4 may be made small to obtain a captured image with a high magnification so that highly accurate alignment can be performed. Further, in the case of performing alignment during component mounting, first, coarse positioning may be performed using the screen mark 3 and then the deviation amount may be finely adjusted using the component mounting mark 4.

As described above, in order to monitor the amount of solder using the solder 6 applied to the component mounting mark 4, an optical reading device 7 is used as shown in the schematic diagram of FIG. The reflected light 7a from the solder 6 is captured. That is, when the applied solder 6 is subjected to the reflow treatment, the solder 6 flows through the entire resist opening 4a.

When the applied amount of the solder 6 is larger than the set value, the protrusion of the solder 6 in the resist opening 4a becomes large. For this reason, the central portion of the solder 6 is curved in a convex shape, and the area of the reflected light 7a captured by the optical reading device 7 arranged above becomes narrower than the size of the resist opening 4a. On the other hand, when the applied amount of the solder 6 is smaller than the set value, the central portion of the solder 6 is dented in the resist opening 4a, and the reflection is taken in by the optical reading device 7 arranged above. The area of the light 7a becomes narrower than the size of the resist opening 4a. Further, when the amount of the solder 6 applied is appropriate, the plane portion of the surface of the solder 6 increases, and the area of the reflected light 7a captured by the optical reading device 7 becomes the resist opening 4a.
Is almost equal to the size of.

That is, it is possible to capture the reflected light 7a from the solder 6 and measure the size of the region, and monitor whether the application amount of the solder 6 is proper or not based on the size. In order to determine whether the coating amount of the solder 6 is large or small, it is possible to make a distinction based on the focal length when the image is obtained by the optical reading device 7. As described above, when the applied amount of the solder 6 is monitored and it is determined that the appropriate amount is not applied, the process on the printed wiring board 1 may not be performed in the subsequent steps. Further, although the case where the center position O of the screen mark 3 and the center position O ′ of the component mounting mark 4 coincide with each other has been described in the present embodiment, the present invention is not limited to this, and the screen mark is not limited thereto. It suffices that the component mounting mark 4 is arranged inside the component 3.

[0021]

As described above, the printed wiring board of the present invention has the following effects. That is, by arranging the component mounting mark inside the screen mark provided outside the wiring pattern region, the area required for installing the mark can be reduced. For this reason, even if the substrates have the same size, the wiring pattern region can be effectively used, which facilitates the design of the printed wiring board. Further, since the component mounting mark is formed of a substantially parallelogram, the reference axis can be easily obtained by image processing, and thus highly accurate alignment can be performed. From these facts, the printed wiring board of the present invention is effective in mounting fine-pitch components at high density.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a printed wiring board of the present invention,
(A) is a plan view and (b) is an enlarged view of a mark portion.

FIG. 2 is an enlarged view of a mark portion after solder application.

FIG. 3 is a diagram showing a captured image.

FIG. 4 is a schematic diagram illustrating a solder amount monitor.

FIG. 5 is a diagram for explaining a conventional printed wiring board, (a)
Is a plan view and (b) is an enlarged view of a component mounting mark.

FIG. 6 is an enlarged view of a screen mark.

FIG. 7 is a cross-sectional view (1) for explaining the alignment of the screen mask.

FIG. 8 is a sectional view (No. 2) for explaining the alignment of the screen mask.

[Explanation of symbols]

1 printed wiring board 2 Wiring pattern area Mark for 3 screens 3a Resist opening 4 Parts mounting mark 4a Resist opening 5 Resist film 6 Solder 10 substrates 31 land 41 land

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Claims (2)

(57) [Claims] 1. A screen mark for aligning a screen mask for applying solder onto a wiring pattern provided on a substrate surface, and a solder provided on the substrate surface and applied to the wiring pattern. In a printed wiring board having a component mounting mark for aligning components to be mounted via, the component mounting mark is provided inside the screen mark, and the screen mark
And the component mounting mark is the same mark that covers the land.
A printed wiring board characterized in that the outer shape of each is formed by opening a dist film . 2. The printed wiring board according to claim 1, wherein the component mounting mark is formed of a substantially parallelogram, and each diagonal line of the substantially parallelogram is used as a reference axis for alignment.