Mounting structure of chip components

Abstract

The mounting structure of the chip component of the present disclosure is a mounting structure of a chip component in which two-terminal electrodes of a small SMD component (2) are soldered to two lands (3) on a printed wiring board (1). The small SMD component (2) has a size of 0.6 mm x 0.3 mm, and the size between the two lands (3) is 0.23 mm or more and 0.25 mm or less.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a mounting configuration of a chip component. BACKGROUND

[0002] Conventionally, as a method of mounting electronic components on a printed wiring board, a flow soldering method and a reflow soldering method are known.

[0003] Patent Document 1 discloses a flow soldering method. The printed wiring board used in the flow soldering method is composed of a substrate formed with substrate electrodes for surface mounting of various circuit elements and openings for insertion of lead terminals of lead components, and a sheet member which is peelable and formed with openings at positions corresponding to the openings of the substrate. Further, an adhesive layer is formed at predetermined positions other than the substrate electrodes formed on the substrate, and the sheet member is used to cover the surface on which the adhesive layer is formed.

[0004] Patent Document 2 discloses a reflow soldering method. The mounting configuration of the reflow soldering method is a mounting configuration of a chip component in which terminal electrodes of both ends of a chip component are soldered to two lands on a printed wiring substrate. In the mounting configuration, the two lands formed on the printed wiring substrate are in a shape in which the opposite sides of a circular shape are partially cut out, and are conductor films in which the two edges formed by the cutting out are substantially parallel to each other.

[0005] Prior art documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. H8-116153

[0008] Patent Document 2: Japanese Patent Application Publication No. 2007-194462 SUMMARY

[0009] The present disclosure provides a mounting configuration of a chip component in which stable adhesion printing is performed on a printed wiring board and small chip components can be mounted.

[0010] The mounting configuration of a chip component of the present disclosure is a mounting configuration of a chip component in which terminal electrodes of both ends of a chip component are soldered to two lands on a printed wiring board in a flow soldering process. The chip component is a small SMD component of 0.6 mm x 0.3 mm, and the size between the two lands is 0.23 mm or more and 0.25 mm or less.

[0011] The mounting structure of the chip component of the present disclosure can achieve stable adhesive printing on a printed wiring board on which a small SMD (Surface Mounted Device) component (for example, 0.6 mm x 0.3 mm (0603 size)) as a chip component is mounted, which has been impossible in the past. Thus, the mounting configuration of the small SMD component can be performed. Also, by limiting the size between the two pads, adhesive printing defects can be eliminated, and the falling of the small SMD component during flow soldering work can be eliminated. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a plan view showing a mounting structure of a chip component of an embodiment.

[0013] Figure 2 is a plan view showing another mounting structure of a chip component of an embodiment. DETAILED DESCRIPTION

[0014] (Insights and the like that became the basis of the present disclosure)

[0015] When the inventors thought of the present disclosure, the productivity of the flow soldering method was very high.

[0016] With the recent miniaturization of SMD components (surface mounted components), the size of the SMD components mounted on printed wiring boards is also miniaturized. As an example, the SMD component surface area also changes from 1.0 mm x 0.5 mm (1005 size) to 0.6 mm x 0.3 mm (0603 size) to about 1 / 2 size.

[0017] In the flow soldering method, the limit of the size of the SMD component that can be flow soldered is set to 1.0 mm x 0.5 mm, and in the flow soldering method, small SMD components that cannot be mounted are also increasing.

[0018] A larger problem when mounting a small SMD component of 0.6 mm x 0.3 mm in size using the flow soldering method is that stable adhesive printing on a printed wiring board is very difficult. The reason for this is that the component size is small, so the pad size and the distance between the pads for adhesive printing to the lower part of the SMD component cannot be ensured.

[0019] Assuming that even if the adhesive printing is performed, the amount of adhesion (joining force) cannot be ensured, at the time of the flow soldering work, there is a case where the small SMD component as an object is detached due to the jet of the solder in the flow channel. In addition, due to the positional shift of the adhesive printing, even if the soldering is performed in the flow channel, there is a case where the solder deficiency, the solder bridging, such soldering defects occur. The inventors found that such a problem that it is difficult to ensure the substrate quality at the time of mounting the small SMD component by using the flow soldering method, and in order to solve the problem, the present disclosure was constructed.

[0020] Thus, the present disclosure provides a chip component mounting structure which enables stable adhesive printing on a printed wiring board and mounting and arrangement of a small chip component.

[0021] Hereinafter, the embodiments will be described in detail with reference to the drawings. However, sometimes, excessively detailed descriptions are omitted. For example, sometimes, detailed descriptions of matters already well known or repeated descriptions of substantially the same structures are omitted. The purpose is to avoid the following description from becoming excessively long and to make it easy for those skilled in the art to understand.

[0022] In addition, the drawings and the following description are provided in order for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims thereby.

[0023] (Embodiments)

[0024] Hereinafter, the embodiments will be described using Figure 1 and Figure 2 .

[0025] [1-1. Structure]

[0026] Figure 1 is a plan view showing the chip component mounting structure of the embodiment. In Figure 1 , the mounting structure of the small SMD component 2 which is a chip component having a size of 0.6 mm x 0.3 mm is shown. Figure 2 The mounting structure described is an example of a structure in which the small SMD component 2 is mounted in a form following the pad shape, and shows an example of a structure in which the solder resist layer is provided in a form following the pad shape in part as an NSMD (Non Solder Mask Defined) structure.

[0027] Two pads 3 are formed on the printed circuit board 1 for mounting small SMD components 2. The dimension t1 between the inner sides of the two pads 3 is set to be 0.23 mm or more and 0.25 mm or less. Furthermore, the dimension t2 of the portion of the pad 3 for mounting the small SMD component 2 is set to 0.2 mm, and the width dimension t3 is set to 0.3 mm. Moreover, the length dimension t4 of each pad 3 is set to be 0.65 mm or more and 1.2 mm or less. The direction of the width dimension t3 is aligned with the width direction of the small SMD component 2. Furthermore, the direction of the length dimension t4 is aligned with the length direction of the small SMD component 2.

[0028] Furthermore, setting the dimension t1 to be between 0.23mm and 0.25mm is problematic. If t1 is less than 0.23mm, printing errors such as adhesive application on the pads 3 may occur due to deviations in the adhesive printing process. Also, if t1 is less than 0.23mm, solder bridging may occur between the terminal electrodes at both ends of the small SMD component 2 during soldering. Additionally, if t1 is greater than 0.25mm, the possibility of soldering errors, such as the terminal electrodes of the small SMD component 2 not being soldered to the pads 3 due to misalignment during component mounting, increases. By setting t1 to between 0.23mm and 0.25mm, these problems can be resolved.

[0029] Furthermore, the length t4 of each of the two pads 3 is set to be 0.65 mm or more and 1.2 mm or less. In the case of a small SMD component 2 with dimensions of 0.6 mm × 0.3 mm, since the pads 3 to be soldered are very small, if the length t4 is less than 0.65 mm, there is a problem that moisture gas may be generated between the substrate and the solder during flow soldering, which may hinder soldering. By setting the length t4 to be 0.65 mm or more and 1.2 mm or less, the above-mentioned problem can be solved. In addition, by setting the length t4 to 1.2 mm or less, small SMD components 2 can be mounted on the printed circuit board 1 at a high density.

[0030] Furthermore, each pad 3 has protrusions 4a in three other directions for drawing circuit patterns 4 connected to the GND pattern, power supply pattern circuit, etc. The protrusions 4a contain copper foil. That is, the pad 3 has protrusions 4a. Moreover, the circuit patterns 4 connected to the pad 3 are connected along the shape of the protrusions 4a by means of the protrusions 4a. In this embodiment, three protrusions 4a are provided, but at least one is sufficient. In other words, protrusions 4a are provided only at the portion of the pad 3 where the circuit patterns 4 are connected (the drawing portion of the circuit patterns 4).

[0031] A solder resist layer 5 is formed around the pads 3 and the circuit pattern 4. The solder resist layer 5 prevents the soldering portion of the pad 3 from becoming abnormally large when a pattern is drawn in the insulating printing (solder resist ink) portion.

[0032] The temporary fixation of the small SMD component 2 is performed by performing adhesive printing between the inner sides of the two pads 3 and placing the small SMD component 2 thereon. In addition, the adhesive printing can be performed using a metal mask or using a dispenser device.

[0033] After that, the printed wiring board is again flipped over, and in the case of a special-shaped electronic component, component mounting is performed using a manual mounter or a mechanical mounter. Then, by performing a flow soldering operation, the printed wiring board 1 and the mounted small SMD component 2 are soldered and energization can be performed.

[0034] Figure 2 is a plan view showing another mounting structure of a chip component according to the embodiment. In Figure 2 a mounting structure of a small SMD component 2 whose size is 0.6 mm x 0.3 mm is shown in Figure 2 In the mounting structure described above, the pattern drawn on each of the two pads 3 indicates a wiring of a solid pattern 6. By connecting the solid pattern 6 to the drawn pattern of the circuit pattern 4, a thermal pattern (a pattern in a cross shape) is formed. That is, in Industrial applicability In the mounting structure described above, the pad 3 has at least two protrusions 4a. Further, on the printed wiring board 1, a solid pattern 6 is provided which is connected to only the at least two protrusions 4a. The solid pattern 6 is connected along the shape of each of the at least two protrusions 4a.

[0035] Thus, a structure in which the pad size of the two pads 3 is not excessively changed can be provided, and in addition, the heat applied to the pads 3 can be suppressed, that is, the temperature of the two pads 3 can be kept the same. Further, the shift of the component, the breakage of the component, and the like can be prevented.

[0036] [1-2. Effects, etc.]

[0037] As described above, in the present embodiment, the mounting structure of the chip component is a mounting structure of a chip component in which the two terminal electrodes of a small SMD component 2 are soldered to the two pads 3 on the printed wiring board 1 in a flow soldering process. The small SMD component is 0.6 mm x 0.3 mm in size, and the size between the two pads 3 is 0.23 mm or more and 0.25 mm or less.

[0038] Thus, it is possible to perform stable adhesive printing on the printed wiring board 1 that has not been possible in the past, and it is possible to perform mounting and arrangement of the small SMD component 2. Furthermore, by limiting the size between the two pads 3, it is possible to eliminate adhesive printing defects and detachment of the small SMD component 2 during flow soldering work.

[0039] Furthermore, by limiting the size between the two pads 3 to 0.23 mm to 0.25 mm, it is possible to eliminate adhesive printing defects and detachment of the small SMD component during flow soldering work.

[0040] Furthermore, the size of the pad 3 in the length direction is 0.65 mm or more and 1.2 mm or less.

[0041] Thus, by limiting the size of the pad 3 in the length direction, it is possible to optimize solder contact and solder wettability during flow soldering work.

[0042] Furthermore, for the mounting structure of the chip component, in the mounting structure of the chip component in which both end terminal electrodes of the chip component are soldered to the two pads on the printed wiring board 1, the shape of the pattern drawn to the pad or the shape of the thermal pad when a solid pattern is drawn is provided.

[0043] Thus, by drawing the pattern wiring along the pattern drawing shape of the protrusion for drawing to the two pads 3, it is possible to moderate the stress applied to the mounted small SMD component 2 with respect to expansion and contraction of the printed wiring board 1, and it is possible to eliminate component damage. Furthermore, when a solid pattern 6 is drawn, by drawing the pattern wiring along the shape of the protrusion 4a to become a thermal pad, it is possible to seek stabilization of the amount of solder during flow soldering work, and thus to seek improvement of soldering quality.

[0044] Furthermore, the pad 3 has a protrusion 4a. Furthermore, the circuit pattern 4 connected to the pad 3 is connected along the shape of the protrusion 4a with the aid of the protrusion 4a.

[0045] Furthermore, the pad 3 has at least two protrusions 4a. A solid pattern that is connected only to the at least two protrusions 4a is provided on the printed wiring board 1. The solid pattern 6 is connected along the shape of each of the at least two protrusions 4a.

[0046] (Other Embodiments)

[0047] As described above, embodiments were described as examples of the technology disclosed in the present application. However, the technology of the present disclosure is not limited thereto, and can be applied to embodiments in which changes, substitutions, additions, omissions, and the like are made.

[0048] Thus, other embodiments will be described below as examples.

[0049] The present application is not limited to the above-described example, and the shape of the chip component can be any shape. Further, the shape of the pad, the pattern, the solder resist layer can also be, for example, a shape with rounded corners, a pattern configuration in which only a portion where a pattern is actually drawn is patterned. It is characterized by being able to solder two pads with the same amount of solder at the time of flow soldering, and being able to make the pressure applied to the terminal portions at both ends of the chip component due to expansion and contraction of the printed wiring board the same.

[0050] In addition, the above-described embodiments are for exemplifying the technology of the present disclosure, and thus various changes, substitutions, additions, omissions, and the like can be made within the scope of the claims or equivalents thereof.

[0051] Legend of the figures

[0052] The mounting structure of the chip component of the present disclosure can achieve an improvement in productivity, inexpensive production costs, which are features of the flow soldering method, and can be applied to various electric appliance products.

[0053] ​

[0054] 1: Printed wiring board; 2: Small SMD component (chip component); 3: Pad; 4: Circuit pattern; 4a: Protrusion; 5: Solder resist layer; 6: Solid pattern.

Claims

1. A chip component mounting structure which welds both terminal electrodes of a chip component at two lands on a printed wiring board in a flow soldering process, wherein the chip component is a small SMD component of 0.6 mm x 0.3 mm, the dimension between the two lands is 0.23 mm or more and 0.25 mm or less, the lands have at least two projections, a solid pattern connected only to the at least two projections is provided on the printed wiring board, and the solid pattern is connected along the shape of each of the at least two projections.

2. The chip component mounting structure according to claim 1, wherein the lengthwise dimension of the lands is 0.65 mm or more and 1.2 mm or less.

3. The chip component mounting structure according to claim 1 or 2, wherein in the chip component mounting structure which welds both terminal electrodes of a chip component at two lands on a printed wiring board, the shape of the pattern drawn to the lands or the shape of the solid pattern when it becomes a hot land is provided.

4. The chip component mounting structure according to claim 1 or 2, wherein the circuit pattern connected to the lands is connected along the shape of the projections by means of the projections. ​ ​ ​ ​

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