JPH10247776A - Land for mounting surface mount components - Google Patents

Abstract

(57) [Problem] To provide a surface mounting component mounting land capable of improving the mounting accuracy while maintaining the solderability of the component even when the width of the resist opening has to be widened. A land (2) on which via holes (5) are formed.
In the resist openings 6a of the resist openings 6a and 2c, the opening width is wide in the region where the via holes 5 and 5 are formed, and substantially equal to the width of the lead portions 4a and 4c in the region where the tips of the leads 4a and 4c are located. The opening width is narrowed so as to be the same. This makes it possible to restrict the position of the lead portion in the narrow opening while securing the solderability in the wide opening, thereby improving the mounting accuracy of the surface mount component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a land for mounting a surface-mounted component having a resist opening electrically connected to a lead of the surface-mounted component, for example, in a conductor pattern formed on a wiring board of a high-frequency circuit. About.

[0002]

2. Description of the Related Art In recent years, the microwave range on the order of GHz has been mainly used mainly for communication between artificial satellites and the ground and reception / transmission of satellite broadcasting. The high-frequency circuit built into these electronic devices is called a hybrid integrated circuit or a hybrid integrated circuit, and various devices (surface-mounted components) are soldered along a conductor pattern called a microstrip line on a wiring board or a metal wiring. It is often made by mounting.

However, in general, the higher the frequency, the shorter the wavelength. Therefore, variations in the mounting accuracy of devices on these wiring boards often greatly affect the characteristics of products. For example, in a circuit design that includes a high electron mobility transistor (HEMT) that is known to operate at a very high speed and has low noise as a device, a general method is to adjust the input impedance of the device to an impedance that does not easily generate noise. Although such a design is performed, if the mounting accuracy of the device is reduced, the input impedance of the device is changed, and noise larger than the designed value is generated. As described above, the decrease in the mounting accuracy of the device is caused by the displacement of the mounting position of each lead portion with respect to the land for mounting the surface mount component on the wiring board.

Therefore, a conventional resist opening of a land for mounting a surface mount component on a wiring board is formed to have a width slightly larger than the width of a component, that is, a lead portion of a device. Here, the resist opening means a conductor region on the component land where the solder resist, which is an insulating and heat-resistant coating material, is not formed, and is electrically connected to the lead portion of the component. It is the part that is done. Thereby, the position of the lead of the component is automatically regulated in the resist opening by the surface tension of the solder melted in the reflow soldering process, and the mounting accuracy of the component is maintained.

[0005]

However, in a component used in a high-frequency circuit, a via hole or a via hole is provided in a component land, and a ground is provided as close as possible to a ground plane of a lead portion of the component. In many cases, good characteristics cannot be obtained unless grounding is taken. In this case, if the resist opening is made as thin as the lead width to the portion where the via hole is formed below the lead portion, the bonding surface with the solder is formed only at the tip portion of the lead portion where the via hole is not formed. Since it is lost, the solderability deteriorates. Therefore, considering this solderability, the resist opening width must be wider than the diameter of the via hole.
As a result, this is a major factor in deteriorating the mounting accuracy of the components, and as described above, there is a problem that the electrical characteristics of the circuit are greatly affected.

[0006] The present invention has been made in view of the above-mentioned problems, and even in a case where the width of the resist opening has to be widened,
It is an object of the present invention to provide a surface mounting component mounting land capable of improving mounting accuracy while maintaining solderability of components.

[0007]

The above objects correspond to a wiring board (for example, reference numeral 1 in the embodiment.
Same. ) Is a land for mounting a surface mount component of a conductor pattern formed on the lead portion (4a,
In the surface mounting component mounting land having the resist opening (6a) electrically connected to 4c), only a part of the resist opening (6a) is connected to the lead (4a, 4c) of the component (3). the width (D ₁₎ and the surface mounting component mounting lands, characterized in that formed in substantially the same (2a, 2
c).

According to the present invention, the width (D) of the resist opening (6a) is substantially the same as the lead width (D ₁ ) of the component (3).
₂ ) Lead portions (4a, 4a)
c) The position is regulated, and the solderability is maintained at the wide opening.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An optimum embodiment of the present invention is a case where a via hole is formed in a land, so that the resist opening width must be increased. In this case, among the resist openings on the lands that are electrically connected to the lead portions of the components, the region in which the via hole is formed is formed with an opening width wider than the diameter of the via hole to secure solderability. The portion where the via hole is not formed at the tip of the lead portion is narrowed in the opening width substantially the same as the width of the lead portion, so that the position of the lead portion and, consequently, the surface mount component is regulated with high precision. The details will be described in the following examples.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a land for mounting a surface mount component according to an embodiment of the present invention. In this embodiment, a case where the present invention is applied to a source land of a HEMT (high electron mobility transistor) generally used in an RF circuit of a satellite broadcast receiving LNB converter will be described with reference to FIG.

The lands 2a and 2 formed on the wiring board 1
b, 2c, and 2d respectively include the lead portions 4a of the HEMT 3;
4b, 4c and 4d are connected. These lead portions 4a-
4d corresponds to a source, a drain, a source, and a gate in order. The land 2a and 2c corresponds to the source land, the size D ₃ of the diameter of 0.80mm holes 5,5
Are formed. Representatively, one source land 2a will be described below.

The via hole 5 is connected to a ground plane on the back surface of the wiring board 1. Opening 6a of resist 6 (indicated by double hatching in the figure) 6 for land 2a
Is that the width D ₄ is formed as large as 1.20 mm in the vicinity of the via hole 5, whereas the resist opening width D ₂ at the tip of the lead portion 4 a (width D ₁ is 0.65 mm) is 0.75 mm. , it is narrowed to a width D ₁ of the substantially lead part 4a. The length of the narrow portion of the opening is 0.4 mm with respect to the total length of 1.3 mm of the resist opening 6a. The area where the resist 6 is covered on the HEMT 3 side of each of the lands 2a to 2d is an area that does not come into contact with each of the lead portions 4a to 4d that bends downward and protrudes. In addition, in order to make the description easy to understand, the scale of each part in the figure does not match the above-mentioned dimension value.

By configuring the resist opening 6a as described above, the solderability is maintained at the wide portion of the resist opening near the via hole 5, and the surface of the solder melted at the narrow portion of the resist opening is maintained. By pulling the lead 4a into the mounting position, that is, the center of the resist opening 6a by tension, the position of the lead 4a can be automatically controlled with high precision.

Although a resist opening is formed in the other source land 2c in the same shape as described above as shown in the figure, the description is omitted. The resist openings are formed in the lands 2b and 2d in which the via holes 5 are not formed, in the same manner as in the related art, as shown in FIG. ± 6mm for width of parts 4b and 4d
It is formed with a tolerance of 0.05 mm and a width of 0.75 mm. That is formed by resist opening width of D ₂ in the land 2a.

According to this embodiment, not only the leads 4b and 4d connected to the lands 2b and 2d but also the leads 4a and 4c connected to the lands 2a and 2c in which the via holes 5, 5 are formed. Again, resist opening 6
Since position control can be performed with high accuracy in the portion of the aperture a having a narrow opening width, the HEMT 3 can be mounted at a predetermined position with high mounting accuracy, and noise figure and gain due to a decrease in mounting accuracy can be obtained. Characteristic variation can be prevented. In addition, since the solderability between the lead portions 4a and 4c can be ensured at the wide portions of the resist openings 6a in the lands 2a and 2c, the reliability of soldering is not reduced. .

As described above, since the via holes 5, 5 exist in the resist opening 6a, the lands 2a and 2
Even if the resist opening width of c must be widened, the surface mount component 3 can be mounted at a predetermined position on the wiring board 1 with high precision simply by changing the shape of the land resist opening. Even if a mounting device having a low mounting capacity is used, the same effect as described above can be obtained.

Although the embodiment of the present invention has been described above, the present invention is, of course, not limited to this, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiment, the dimension values D _{1 to} D ₄ of the land 2a are not limited to these. It can be appropriately changed according to the width of the lead portion 4a, the diameter of the via hole 5, and the like. Although the opening width of the resist opening 6a corresponding to the tip of the lead 4a is set to 0.75 mm, which is 0.10 mm larger than the width of the lead 4a, the only purpose is to improve the mounting accuracy of the components. For example, in general, the smaller the difference, the better. Therefore, the size is not limited to the above embodiment. Further, the shape of the resist opening 6a can be determined as follows.

As shown in FIG. 2, the resist 11 selects each area obtained by dividing the shape of the opening 11a of the resist 11 applied to the land 12 into a plurality (9 areas in the figure) of an arbitrary size. It can be formed by covering it. That is, in the figure, when the lead portion of the component is located in the region and the region, and there is a via hole in the region and the region, (,,,)
One of the three sets of (,) or (,) is covered with the resist 11, and a via hole is formed.
When present over the regions of, and
A portion of the resist opening 11a may be formed to be substantially the same as the width of the lead portion so that the region of the set (2) is covered with the resist 11. Although it depends on the position of the via hole, it is conceivable that the resist 11 is covered with a combination of (,,), (,) in addition to the above. in this way,
By appropriately changing the shape of the resist opening according to the position and size of the via hole, and furthermore, the shape of the lead portion, etc., a land for mounting a surface mount component having both good solderability and high precision position regulation is formed. be able to.

In the above embodiment, the HEMT (high electron mobility transistor) used in a high-frequency circuit has been described as a surface-mounted component. However, the present invention is not limited to this, and is applicable to a surface-mounted semiconductor package component such as another transistor. However, the present invention is applicable.

[0021]

As described above, according to the surface mounting component mounting land of the present invention, only a part of the resist opening is formed to be substantially the same as the width of the lead portion of the component. Even if it is necessary to increase the size of the mounting part, it is possible to regulate the position of the lead in the narrow opening while securing the solderability in the wide opening, and regardless of the ability of the mounting device, Mounting accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a land for mounting surface mounting components according to an embodiment of the present invention.

FIG. 2 is a plan view for explaining the modification.

[Explanation of symbols]

1 ... wiring board, 2a-2d ... land, 3 ... parts,
4a to 4d: lead portion, 5: via hole, 6: resist, 6a: resist opening.

Claims (4)

[Claims] 1. A surface mounting component mounting land of a conductive pattern formed on a wiring board, the land having a resist opening electrically connected to a lead portion of the component. A land for mounting a surface mount component, wherein only a part of the resist opening is formed to have substantially the same width as a lead portion of the component. 2. The mounting surface mounting device according to claim 1, wherein the resist opening is formed by selectively covering a plurality of regions divided into arbitrary sizes by a resist. land. 3. The surface mounting component mounting land according to claim 1, wherein a via hole that connects between layers of the wiring board is formed in the resist opening. 4. The land for mounting a surface mount component according to claim 1, wherein the component is a high electron mobility transistor.