TWI912745B - substrate and module - Google Patents

Abstract

The present invention discloses a substrate capable of supplying more solder to solder pads. The substrate includes: a substrate layer; a conductive layer deposited on the substrate layer; and a solder resist deposited on the conductive layer such that the conductive layer is sandwiched between the conductive layer and the substrate layer. The conductive layer has an uncovered portion, viewed from the stacking direction of the substrate layer, the conductive layer, and the solder resist, that is not covered by the solder resist in a top view. The uncovered portion has solder pads for connecting to electronic components and an extension extending from the solder pads in a top view.

Description

substrate and module

This disclosure relates to a substrate for mounting electronic components and a module including the substrate.

Previously, such substrates have been known as, for example, the substrate described in Patent Document 1. The substrate described in Patent Document 1 includes: a substrate layer; an insulating layer deposited on the substrate layer; and a solder pad disposed on the insulating layer and connected to the terminals of an electronic component. A first solder resist, formed in a manner that surrounds the solder pad when viewed from above, is disposed on the insulating layer. That is, a first opening surrounding the solder pad is provided in the first solder resist. A second solder resist, formed on the first solder resist in a manner that surrounds the first opening when viewed from above, is formed.

When mounting electronic components onto a substrate, solder paste is filled into the internal spaces of the first and second openings. After the terminals of the electronic components are disposed on the solder paste, the substrate is heated to melt the solder paste, thereby connecting the terminals of the electronic components to the solder pads via the solder paste. [Prior Art Documents] [Patent Documents]

[Patent Document 1] Japanese Patent Application Publication No. 2012-156257

[Problem to be Solved by the Invention] From the perspective of increasing the amount of solder supplied to the solder pads, the substrate of Patent 1 still has room for improvement.

Therefore, the purpose of this disclosure is to solve the aforementioned problem and provide a substrate capable of supplying more solder to the solder pads. [Means of Solving the Problem]

The disclosed substrate includes: a substrate layer; a conductive layer deposited on the substrate layer; and a solder resist deposited on the conductive layer such that it sandwiches the conductive layer between the substrate layer and the conductive layer, the conductive layer has a non-covered portion, viewed from the stacking direction of the substrate layer, the conductive layer, and the solder resist, not covered by the solder resist in a top view, the non-covered portion has solder pads for connecting to electronic components, and an extension extending from the solder pads in a top view. [Effects of the Invention]

This disclosure provides a substrate that can supply more solder to the solder pad.

<Views that form the basis of this disclosure> In the substrate described in Patent Document 1, solder filling the internal spaces of the first and second openings—that is, solder supplied to the solder pads—connects the terminals of electronic components to the solder pads. The amount of solder that can be supplied to the solder pads is limited by the volume of the internal spaces. Therefore, if more solder is desired to supply to the solder pads, the internal spaces need to be enlarged.

As a countermeasure to increase internal space, as described in Patent 1, one consideration is to thicken the solder resist surrounding the pads to increase the height of the internal space. However, there are manufacturing limitations on the thickness of each layer of solder resist. Furthermore, stacking multiple layers of solder resist increases the number of steps in substrate manufacturing and the cost of substrate production.

Therefore, the inventors have diligently researched and developed a substrate capable of supplying more solder to the solder pad. As a result, the inventors conceived of providing an extension extending from the solder pad on the uncoated portion of the conductive layer not covered by solder resist. When solder (solder paste) is applied to and melted on the extension and the solder resist surrounding the extension, the solder on the solder resist surrounding the extension flows into the extension. This results in an excess of solder on the extension. This excess solder on the extension is supplied to the solder pad. Thus, compared to the case where solder is only applied to the solder pad, the amount of solder supplied to the solder pad can be increased. Based on this novel insight, the inventors have achieved the following disclosure.

The embodiments of this disclosure will now be described with reference to the accompanying drawings. Furthermore, in the following description, terms indicating specific directions or positions (e.g., terms such as "up," "down," "right," and "left") will be used as needed. These terms are used to facilitate understanding of this disclosure with reference to the drawings, and the technical scope of this disclosure is not limited by the meanings of these terms. Additionally, the following description is essentially illustrative and is not intended to limit this disclosure, its applicability, or its uses. Moreover, the drawings are schematic, and the proportions of the dimensions may not necessarily correspond to actual proportions.

In this specification, "electrical connection" includes any of the following: a situation in which current can conduct between multiple components, multiple components are capacitively coupled, and multiple components are electromagnetically coupled.

Furthermore, the terms "layer" and "membrane" are not intended to limit the thickness of the constituent components referred to by each term. That is, the thickness of a layer can be less than or greater than the thickness of a membrane, or it can be the same as the thickness of a membrane.

<First Embodiment> The substrate of the first embodiment of this disclosure will be described with reference to Figures 1 and 2. Figure 1 is a plan view of the substrate of the first embodiment of this disclosure. Figure 2 is a cross-sectional view of the substrate of Figure 1 along line II-II. An orthogonal X-Y-Z coordinate system is shown in the figures for ease of explanation, but this coordinate system is for the purpose of easily understanding the coordinates of this disclosure and does not limit the scope of this disclosure.

In this specification, the term "substrate" includes both a printed wiring board with printed wiring but no electronic components mounted thereon and a printed circuit board with electronic components mounted thereon. That is, the substrate in this specification may or may not have electronic components mounted on it.

The substrate 1 in the first embodiment is a substrate capable of mounting electronic components such as power semiconductors and large-scale integrated circuits (LSI). As shown in Figures 1 and 2, the substrate 1 in the first embodiment is formed as a laminate consisting of a substrate layer 10, a conductive layer 20, and a solder resist 30. For example, the substrate 1 is a printed circuit board, a ceramic substrate, or a flexible substrate. In this embodiment, the top view of the substrate 1 is rectangular when viewed from the lamination direction of the substrate layer 10, the conductive layer 20, and the solder resist 30 (hereinafter also referred to as the "lamination direction").

In the following description and figures, the direction of the longer side of substrate 1 when viewed from above is sometimes referred to as the X-axis, the direction of the shorter side of substrate 1 when viewed from above is referred to as the Y-axis, and the lamination direction is referred to as the Z-axis. The X-axis intersects (e.g., orthogonally) the Y-axis. The Z-axis intersects (e.g., orthogonally) both the X-axis and the Y-axis.

The substrate layer 10 shown in Figure 2 contains a material corresponding to the type of substrate 1. In this embodiment, substrate 1 is a printed circuit board, and substrate layer 10 is an insulating layer in a copper-clad laminate used for double-sided substrates. The material of the insulating layer is resin, glass, ceramic, etc. Substrate 1 can be a single-layer substrate, or it can be a multi-layer substrate containing two or more insulating layers and wiring patterns disposed between these insulating layers.

A conductive layer 20 is deposited on the substrate layer 10. The conductive layer 20 has a lower surface 20a facing the substrate layer 10 in the deposition direction (Z-axis direction) and an upper surface 20b on the opposite side. The conductive layer 20 is patterned on the substrate layer 10 in such a way as to form wiring, coils, or other components that are electrically connected to electronic components mounted on the substrate 1. The material of the conductive layer 20 is, for example, copper, gold, silver, palladium, nickel, platinum, or alloys thereof. In this embodiment, the conductive layer 20 is a copper foil of a copper-clad laminate.

Solder resist 30 is deposited on the upper surface 20b of conductive layer 20 such that a conductive layer 20 is sandwiched between it and substrate layer 10. As shown in FIG1, solder resist 30 covers a portion of the upper surface 20b of conductive layer 20. Specifically, a hole 31 is provided in solder resist 30.

When viewed from above, the portion of the conductive layer 20 corresponding to the hole 31 is the uncovered portion 21 that is not covered by the solder resist 30. That is, the uncovered portion 21 constitutes the bottom of the hole 31.

As shown in Figure 2, a plating film 40 is provided in the area corresponding to the non-coated portion 21 on the upper surface 20b of the conductive layer 20. For example, the plating film 40 is a tin plating film, a nickel-tin plating film, or a nickel-electrolytic gold plating film. In this embodiment, the plating film 40 is a tin plating film. This tin plating film is formed, for example, by immersing a substrate with the non-coated portion 21 exposed through the hole portion 31 in a plating solution.

As shown in FIG1, the non-covered portion 21 has a solder pad 22 that connects to an electronic component mounted on the substrate 1, and an extension portion 23 extending from the solder pad 22 along the surface direction of the substrate 1 that intersects the lamination direction (Z-axis direction). In the following description, the area in the upper surface 20b of the conductive layer 20 that corresponds to the solder pad 22 is referred to as the surface 22a of the solder pad 22, and the area that corresponds to the extension portion 23 is referred to as the surface 23a of the extension portion 23.

In this embodiment, the solder pad 22 is a thermal solder pad connected to the thermal electrode (described later) of the electronic component mounted on the substrate 1. The shape of the solder pad 22 in top view is, for example, polygonal, circular, or elliptical. In this embodiment, the shape of the solder pad 22 in top view is rectangular. Specifically, the outer edge 221 of the solder pad 22 is composed of edges extending along the X-axis and Y-axis directions respectively.

The shape of the enlarged portion 23 in top view is, for example, polygonal, circular, or elliptical. In this embodiment, the shape of the enlarged portion 23 in top view is a linear shape extending from the outer edge 221 of the solder pad 22 in a direction intersecting the outer edge 221. More specifically, the shape of the enlarged portion 23 in top view is a rectangle extending from the portion extending along the Y-axis of the outer edge 221 of the solder pad 22 in the X-axis direction. The dimension D2 of the enlarged portion 23 in the Y-axis direction is smaller than the dimension D1 of the solder pad 22 in the Y-axis direction.

The enlarged portion 23 has at least one linear portion 24 that is linear in shape when viewed from above. In this embodiment, the enlarged portion 23 as a whole constitutes a linear portion 24. That is, the linear portion 24 has a linear shape extending from the solder pad 22. In this embodiment, the linear portion 24 extends along the X-axis direction.

In this embodiment, the enlargement 23 is integrated with the solder pad 22, but is not connected to other conductors disposed on the substrate 1. That is, the enlargement 23 may not function as a wiring device connecting the solder pad to the conductors disposed on the substrate 1. The area of the enlargement 23 in top view may be larger or smaller than the area of the solder pad 22 in top view.

As shown in Figure 1, the solder resist 30 has multiple terminal openings 32 formed around the solder pad 22. In this embodiment, the eight terminal openings 32 are arranged such that they clamp the solder pad 22 in the Y-axis direction.

The portion of the conductive layer 20 that corresponds to each terminal opening 32 when viewed from above constitutes a terminal electrode portion 27. That is, the conductive layer 20 has eight terminal electrode portions 27. Four terminal electrode portions 27 are provided on each side of the solder pad 22 in the Y-axis direction. Each terminal electrode portion 27 is connected to the terminal of an electronic component mounted on the substrate 1. Similar to the non-covered portion 21, the terminal electrode portions 27 are not covered by solder resist 30.

As shown in Figures 1 and 2, a shape display portion 50 is deposited on the solder resist 30. The shape display portion 50 is formed along the shape of the electronic component connected to the solder pad 22 during installation. In this embodiment, the top view shape of the shape display portion 50 corresponds to the rectangular shape of the electronic component in top view, and is a generally rectangular shape formed by sides extending along the X-axis and Y-axis directions respectively. As shown in Figure 1, in this embodiment, a portion of the enlarged portion 23 and the solder pad 22 are surrounded by the shape display portion 50.

The module 100 on which electronic components 110 are mounted on substrate 1 will be described with reference to Figures 3 and 4. Figure 3 is a plan view of the module including the substrate of Figure 1. In Figure 3, the portions of the solder pads 22 and the enlarged portions 23 that overlap with the electronic components 110 when viewed from above are indicated by dashed lines. Figure 4 is a cross-sectional view of the module of Figure 3 along line IV-IV.

Electronic component 110 may be a surface mount component such as a power semiconductor, a large-scale integrated circuit (LSI), a resistor, or a capacitor. In this embodiment, electronic component 110 is formed as a cuboid. As shown in FIG4, a heat dissipation electrode 111 is provided on the bottom surface 110a of electronic component 110 for dissipating heat generated inside electronic component 110 to substrate 1.

The heat dissipation electrode 111 of the electronic component 110 is connected to the solder pad 22 of the substrate 1 via solder 120. The solder pad 22 may be connected to the heat dissipation electrode 111 over its entire surface when viewed from above, or it may be connected to only a portion of the heat dissipation electrode 111 when viewed from above. In this embodiment, the shape and size of the heat dissipation electrode 111 when viewed from above are the same as the shape and size of the solder pad 22 when viewed from above. Therefore, the entire surface of the solder pad 22 when viewed from above is connected to the heat dissipation electrode 111 via solder 120.

As shown in Figures 3 and 4, solder 120 is not only disposed on the solder pad 22, but also throughout the entire uncovered portion 21 when viewed from above, and further disposed on the terminal electrode portion 27 (see Figure 1).

As shown in Figure 3, at least a portion of the enlargement 23 is located offset from the electronic component 110 when viewed from above. That is, the enlargement 23 has a portion that does not overlap with the electronic component 110 when viewed from above. The enlargement 23 is not connected to the electronic component 110 in the lamination direction (Z-axis direction).

Each terminal electrode portion 27 (see FIG1) is connected to the terminals such as the outer lead of the electronic component 110 via solder provided on each terminal electrode portion 27.

An example of a method for mounting electronic component 110 on substrate 1 will be described. First, solder paste, including solder 120 that connects heat dissipation electrode 111 to solder pad 22, is applied to substrate 1. Specifically, the solder paste is applied to areas PS1 and PS2 enclosed by the dotted line shown in FIG1. Area PS1 is the area formed by solder pad 22 and the portion of solder resist 30 adjacent to solder pad 22 when viewed from above. Area PS2 is the area formed by at least a portion of enlargement 23 and the portion of solder resist 30 adjacent to enlargement 23 when viewed from above. For example, the area of area PS2 when viewed from above is larger than the area of enlargement 23 when viewed from above. For example, a metal mask with openings corresponding to the shapes of regions PS1 and PS2 is used to apply solder paste.

Next, the electronic component 110 is disposed on the substrate 1. At this time, the heat dissipation electrode 111 is in contact with the solder paste on the solder pad 22. In addition, the terminals (not shown) of the electronic component 110 are in contact with the solder paste applied to the terminal electrode portions 27.

Next, the substrate 1, on which the electronic components 110 are disposed, is heated, for example, in a reflow oven. Thereby, the solder 120 contained in the solder paste melts. In region PS2, the solder 120 on the solder resist 30 is deflected by the solder resist 30 and moves to the expansion section 23, as indicated by the arrow in FIG1. The solder 120 moving to the expansion section 23 flows along the expansion section 23 toward the solder pad 22. That is, the expansion section 23 functions as a flow path for the solder 120 located on the solder resist 30 in region PS2 to flow toward the solder pad 22.

In this way, in addition to the solder 120 applied to area PS1, at least a portion of the solder 120 applied to area PS2 is also supplied to the solder pad 22. By supplying more solder 120 to the solder pad 22, the solder 120 rises higher on the solder pad 22 along the Z direction. Therefore, the reliability of the solder 120-based connection between the heat dissipation electrode 111 and the solder pad 22 is improved.

According to the substrate 1 of the first embodiment, an extension 23 extending from the solder pad 22 is provided. When solder 120 (solder paste) is applied to the extension 23 and the solder resist 30 around the extension 23 (i.e., area PS2) and melted, the solder on the solder resist 30 around the extension 23 flows into the extension 23. As a result, there is an excess of solder 120 on the extension 23. This excess portion of solder 120 on the extension 23 is supplied to the solder pad 22. Therefore, compared to a structure without the extension 23, the amount of solder 120 supplied to the solder pad 22 can be increased. Consequently, the reliability of the solder 120-based connection between the heat dissipation electrode 111 and the solder pad 22 can be improved.

Furthermore, in the substrate 1 disclosed herein, even if the solder resist 30 is only one layer, the amount of solder supplied to the solder pad 22 can be increased. Therefore, compared with existing substrates that require two or more layers of solder resist, the number of steps in the substrate manufacturing process and the cost of substrate manufacturing can be reduced.

Furthermore, according to the substrate 1 of the first embodiment, the enlarged portion 23 has at least one linear portion 24. In the linear portion 24, which is linear in shape, the flow of molten solder 120 is easily oriented along the extending direction of the linear portion 24. Therefore, compared to a structure where the enlarged portion 23 does not have a linear portion 24, the solder 120 on the enlarged portion 23 flows more easily toward the solder pad 22. Therefore, the amount of solder 120 supplied to the solder pad 22 can be increased more reliably.

Furthermore, according to the substrate of the first embodiment, a plating film 40 is provided on the surface 23a of the expanded portion 23. By providing the plating film 40, the wettability of the solder 120 on the expanded portion 23 is improved. As a result, compared with the structure without the plating film 40, the molten solder 120 flows more easily on the expanded portion 23. Therefore, the amount of solder 120 supplied to the solder pad 22 can be increased more reliably.

Furthermore, according to the first embodiment of the module 100, as described above, the amount of solder 120 connecting the pad 22 to the heat dissipation electrode 111 and the amount of solder 120 supplied to the pad 22 via the expansion section 23 are correspondingly increased. Therefore, the reliability of the solder 120-based connection between the pad 22 and the heat dissipation electrode 111 is improved.

<Second Embodiment> The substrate of the second embodiment of this disclosure will be described with reference to FIG. 5. FIG. 5 is a plan view of the substrate of the second embodiment of this disclosure.

The shape of the substrate 1A in the second embodiment when viewed from above in terms of the enlarged portion 23 and the enlarged portion 23A differs from that of the substrate 1 in the first embodiment. Furthermore, in the following description of the second embodiment, the same reference numerals are sometimes used to mark structures identical to those of the substrate 1, and the description is omitted.

As shown in Figure 5, the enlarged portion 23A in the substrate 1A has a linear portion 24 extending from the solder pad 22 when viewed from above, and one or more branch portions 25 branching from the linear portion 24 and extending linearly. In this embodiment, the enlarged portion 23A has ten branch portions 25. Five of the ten branch portions 25 extend on each side of the linear portion 24 in the Y-axis direction. In this embodiment, the ten branch portions 25 are not connected to each other but are arranged separately.

Each branch 25 has a base end 25a connected to the linear portion 24, and an end portion 25b on the opposite side. Each branch 25 can be, for example, straight or curved. In this embodiment, the ten branches 25 are straight and formed in a linearly symmetrical manner with respect to the linear portion 24. That is, the ten branches 25 have the same length. In addition, each of the ten branches 25 forms the same angle with the linear portion 24.

Each branch 25 extends in a manner that approaches the pad 22 in the extension direction (X-axis direction) of the linear portion 24 from the end portion 25b toward the base end portion 25a.

When an electronic component 110 is mounted on a substrate 1A (see FIG3), the area PS2 for solder paste application is provided, for example, in a manner that includes the end portion 25b of all branches 25.

According to the substrate 1A of the second embodiment, the enlargement 23 has at least one branch 25 that branches off from and extends from the linear portion 24. By providing the branch 25, solder 120 can be supplied to the solder pad 22 from a wider area on the solder resist 30 via the enlargement 23. In other words, compared with a structure without the branch 25, the area where solder 120 (solder paste) to be supplied to the solder pad 22 can be applied can be expanded. Therefore, the amount of solder 120 supplied to the solder pad 22 can be further increased.

Furthermore, the solder 120 located in the area sandwiched between the linear portion 24 and the branch portion 25 in the solder resist 30 can flow into either the linear portion 24 or the branch portion 25. Therefore, the solder 120 located in this area is less likely to remain on the solder resist 30 when it melts, and can be easily supplied to the solder pad 22 through the expansion portion 23.

Furthermore, when multiple branches 25 extend and are arranged in a mutually extending manner, the solder 120 located in the area sandwiched between them can flow into any branch 25. Therefore, the solder 120 located in this area is less likely to remain on the solder resist 30 when it melts, and can be easily supplied to the solder pad 22 via the expansion section 23. Therefore, the solder 120 disposed on the solder resist 30 in the area PS2 can be supplied to the solder pad 22 more reliably.

Furthermore, according to the substrate 1A of the second embodiment, each branch 25 has a shape that extends toward the solder pad 22 in the extending direction of the linear portion 24 from the end portion 25b toward the base end portion 25a. Therefore, the flow of solder 120 flowing in the linear portion 24 is less likely to be obstructed at the confluence of the linear portion 24 and the branch 25. Therefore, compared to structures where each branch 25 has a shape other than the aforementioned shape, it is easier for the solder to flow toward the solder pad 22. Therefore, the amount of solder 120 supplied to the solder pad 22 can be increased more reliably.

<Third Embodiment> The substrate of the third embodiment of this disclosure will be described with reference to FIG. 6. FIG. 6 is a plan view of the substrate of the third embodiment of this disclosure.

The shape of the substrate 1B in the third embodiment, when viewed from above, differs from that of the substrate 1 in the first embodiment. Furthermore, in the following description of the third embodiment, the same reference numerals are sometimes used for structures identical to those of the substrate 1, and the description is omitted.

As shown in Figure 6, the enlarged portion 23B in the substrate 1B has multiple linear portions 24 when viewed from above. In this embodiment, three linear portions 24 are provided, each extending from a different position on the outer edge 221 of the solder pad 22. In other words, multiple connection portions are provided between the enlarged portion 23B and the solder pad 22. The three linear portions 24 extend along the X-axis and are separated from each other.

When electronic components 110 are mounted on substrate 1B (see FIG. 3), as shown in FIG. 6, the area PS2 for solder paste application can also be provided in each of the three linear portions 24. In this case, each area PS2 is an area formed by a linear portion 24 and the portion of solder resist 30 adjacent to the linear portion 24 when viewed from above. Alternatively, an area PS2 may also include three linear portions 24 and the portions of solder resist 30 adjacent to each linear portion 24.

According to the substrate 1B of the third embodiment, multiple connection portions are provided between the expansion portion 23B and the solder pad 22. Therefore, compared with a structure having only one connection portion, the amount of solder 120 that can be supplied from the expansion portion 23B to the solder pad 22 within a certain time is increased. This further increases the amount of solder 120 supplied to the solder pad 22.

<Fourth Embodiment> The substrate of the fourth embodiment of this disclosure will be described with reference to FIG. 7. FIG. 7 is a plan view of the substrate of the fourth embodiment of this disclosure.

The substrate 1C of the fourth embodiment differs from the substrate 1 of the first embodiment in that the shapes of the enlarged portions 23 and 23C when viewed from above. Furthermore, a through-hole 222 is provided on the solder pads 22C of the substrate 1C, penetrating the conductive layer 20 along the lamination direction (Z-axis direction). Additionally, the substrate 1C does not have a shape display portion 50. Moreover, in the following description of the fourth embodiment, the same reference numerals are sometimes used for structures identical to those of the substrate 1, and descriptions are omitted.

As shown in Figure 7, the solder pad 22C in the substrate 1C is the portion of the non-covered portion 21 that is surrounded by an imaginary straight line VL (the dashed line in Figure 7) that connects the outer edges of multiple terminal electrode portions 27 when viewed from above. The imaginary straight line VL connects the outer edges of the multiple terminal electrode portions 27 in a manner that maximizes the area enclosed by the imaginary straight line VL. On the other hand, the enlarged portion 23C is located further outward than the imaginary straight line VL.

A plurality of through holes 222 are provided on a portion of the substrate 1C. In a fourth embodiment, the through holes 222 are provided on the pads 22C in the substrate 1C, but not on the expansion portion 23C in the substrate 1C. The plurality of through holes 222 are formed in a manner that creates a plurality of columns extending along the Y-axis and arranged in the X-axis direction. In each column, the through holes 222 are arranged at equal intervals. The plurality of columns are formed by arranging two columns in the X-axis direction. In the two columns, the through holes 222 of one column are staggered from the through holes 222 of the other column in the Y-axis direction. The through holes 222 of one column in each group are arranged relative to each other along the X-axis direction, and the through holes 222 of the other column in each group are also arranged relative to each other along the X-axis direction. That is, the multiple through holes 222 also constitute multiple columns arranged along the Y-axis direction.

In this embodiment, the through hole 222 is a through hole. That is, the through hole 222 provided on the solder pad 22C penetrates the substrate layer 10, the conductive layer 20, and the plating film 40 in the lamination direction (Z-axis direction). In addition, when viewed from above on the substrate 1C, the through hole 222 formed in the area where the solder resist 30 is provided penetrates the substrate layer 10, the conductive layer 20, the solder resist 30, and the plating film 40.

The enlarged portion 23C has a linear portion 24C that extends at an angle of approximately 30 degrees relative to the X-axis when viewed from above, and 30 first branch portions 25C. The first branch portions 25C correspond to the branch portions 25 in the second embodiment. That is, each first branch portion 25C branches from the linear portion 24C and extends linearly.

The enlarged portion 23C further has a straight second branch 26 branching from a first branch 25C. In this embodiment, four second branches 26 are provided. As shown in FIG7, the enlarged portion 23C extends at a position offset from the through-hole 222. Since the through-hole 222 is not provided in the enlarged portion 23C, the solder 120 flowing in the enlarged portion 23C will not enter the through-hole 222 when the electronic component 110 is mounted on the substrate 1C. Thereby, the reduction of solder 120 supplied from the enlarged portion 23C to the solder pad 22C is suppressed.

According to the fourth embodiment of the substrate 1C, a through-hole 222 is provided on the solder pad 22, which penetrates the conductive layer 20 along the lamination direction (Z-axis direction). When the electronic component 110 (see FIG. 3) is mounted on the substrate 1C, the solder 120 molten on the solder pad 22 enters the through-hole 222 provided in the solder pad 22. By filling the through-hole 222 with solder 120, the heat conducted from the heat dissipation electrode 111 of the electronic component 110 to the solder pad 22 is dissipated to the side of the substrate 1C opposite to the side where the electronic component 110 is mounted through the solder 120 in the through-hole 222.

Solder 120 on pad 22 enters through-hole 222, and solder 120 disposed in region PS2 is introduced into pad 22. Thus, solder 120 is supplied from region PS2 to pad 22, so even though solder 120 fills through-hole 222, insufficient solder 120 on pad 22 is suppressed. Therefore, even in pad 22 with through-hole 222, the reliability of the solder 120-based connection between pad 22 and heat dissipation electrode 111 can be improved. Furthermore, insufficient solder 120 on pad 22 is less likely, thus increasing the filling rate of solder 120 in through-hole 222 formed in pad 22. Therefore, the heat dissipation of electronic component 110 can be improved.

Furthermore, this disclosure is not limited to the described embodiment and can be implemented in various other forms. For example, in the first embodiment, the solder pad 22 is connected to the heat dissipation electrode 111 of the electronic component 110, but this disclosure is not limited to this. For example, the solder pad 22 can also be connected to the terminal of the electronic component 110 via solder. In this case, the amount of solder 120 supplied to the solder pad 22 is increased, and the solder 120 is raised. Thereby, even if the distance between the surface 22a of the solder pad 22 and the terminal deviates due to the tolerance of the length or angle of the terminal, the solder 120 can more reliably connect the solder pad 22 to the terminal.

In the first embodiment, the plating film 40 is disposed in the area corresponding to the non-covered portion 21 on the upper surface 20b of the conductive layer 20, but this disclosure is not limited to this. For example, the plating film 40 may be disposed only in the area corresponding to the enlarged portion 23 on the upper surface 20b, and not in the area corresponding to the solder pad 22. Alternatively, the plating film 40 may be disposed on the entire surface of the upper surface 20b of the conductive layer 20, or it may not be disposed on the substrate 1.

Additionally, as stated above, the entire surface of the solder pad 22 in top view is connected to the heat dissipation electrode 111, but this disclosure is not limited to this. For example, the solder pad 22 may also be larger than the heat dissipation electrode 111, with only a portion of the solder pad 22 connected to the heat dissipation electrode 111.

In addition, in the first embodiment, the solder 120 is disposed across the entire surface of the uncovered portion 21 in a top view, but this disclosure is not limited to this. For example, the solder 120 may also be disposed on a portion of the expanded portion 23 and the entire surface of the solder pad 22. In this case, the solder on the solder pad 22 and the solder on the expanded portion 23 may also be integral.

In the second embodiment, multiple branches 25 are formed in a linearly symmetrical manner relative to the linear portion 24, but this disclosure is not limited to this. For example, the multiple branches 25 may also be arranged offset on both sides of the linear portion 24 in the Y-axis direction. The shapes of the multiple branches 25 in top view may also be different from each other.

In another embodiment, the solder pad 22 is described as the portion surrounded by an imaginary straight line VL connecting the outer edges of the plurality of terminal electrode portions 27, but this disclosure is not limited to this. For example, the solder pad 22 may also be the portion of the non-covered portion 21 that is surrounded by the outline display portion 50 (see FIG. 1) when viewed from above. In this case, the enlarged portion 23C may also be the portion of the non-covered portion 21 that is further outward than the outline display portion 50 when viewed from above.

In addition, in the first embodiment, the outline display portion 50 (see FIG. 1) disposed on the solder resist 30 is formed along the outline of the electronic component when it is installed in the plane, but this disclosure is not limited to this. For example, the outline display portion 50 may also be formed only along the four corners of the outline of the electronic component 110, which is rectangular when viewed from above. In this case, the solder pad 22 may also be the portion of the non-covered portion 21 that is surrounded by the four outline display portions 50 and the imaginary straight lines connecting them when viewed from above.

By appropriately combining any of the various embodiments or variations, their respective effects can be achieved. Furthermore, it is possible to combine embodiments with each other, embodiments with each other, or embodiments with embodiments, and it is also possible to combine features of different embodiments with each other.

Although this disclosure is fully described with reference to the accompanying drawings and in conjunction with preferred embodiments, various modifications or alterations will be apparent to those skilled in the art. It should be understood that such modifications or alterations are included therein, provided they do not depart from the scope of this disclosure based on the appended patent application.

The various embodiments of this disclosure have been explained in detail above with reference to the figures. Finally, the various forms of this disclosure are explained. Furthermore, in the following description, reference symbols are also added as examples.

According to the first aspect disclosed herein, a substrate (1, 1A-1C) is provided, comprising: a substrate layer (10); a conductive layer (20) deposited on the substrate layer (10); and a solder resist (30) deposited on the conductive layer (20) such that the conductive layer (20) is sandwiched between the conductive layer (20) and the substrate layer (10), the conductive layer (20) has a non-covered portion (21) not covered by the solder resist (30) when viewed from the stacking direction of the substrate layer (10), the conductive layer (20), and the solder resist (30), The uncoated portion (21) has solder pads (22, 22C) for connection to electronic components, and enlargements (23, 23A-23C) extending from the solder pads (22, 22C) when viewed from above.

According to the second aspect of this disclosure, a substrate (1, 1A to 1C) as described in the first aspect is provided, wherein the enlarged portion (23, 23A to 23C) has at least one linear portion (24, 24C) that is linear in shape when viewed from above.

According to the third aspect of this disclosure, a substrate (1A, 1C) as described in the second aspect is provided, wherein the enlarged portion (23A, 23C) has one or more branches (25) extending linearly from the linear portion (24, 24C) when viewed from above.

According to the fourth aspect of this disclosure, a substrate (1A, 1C) as described in the third aspect is provided, wherein at least one of the branches (25) has a base end portion (25a) connected to the linear portion (24, 24C), and an end portion (25b) opposite to the base end portion (25a), the branch portion (25) extends in a manner that approaches the solder pad (22, 22C) in the extending direction of the linear portion (24, 24C) from the end portion (25b) toward the base end portion (25a).

According to the fifth state pattern disclosed herein, a substrate (1, 1A to 1C) containing any one of the first to fourth state patterns is provided, wherein a coating film (40) is provided on the surface (23a) of the enlarged portion (23, 23A to 23C).

According to the sixth state of this disclosure, a substrate (1C) recorded in any of the first to fifth state samples is provided, wherein a through hole (222) is provided in the pad (22C) to penetrate the conductive layer (20) along the stacking direction.

According to the seventh state pattern disclosed herein, a substrate (1, 1A, 1B) provided with any one of the first to sixth state patterns has a shape display portion (50). The shape display portion (50) is deposited on the solder resist (30) such that the solder resist (30) is sandwiched between the conductive layer (20), and is formed, when viewed from above, along the shape of the electronic component when connected to the uncovered portion (21). The solder pads (22, 22C) are portions of the uncovered portion (21) that are surrounded by the shape display portion (50) when viewed from above. The enlarged portions (23, 23A, 23B) are located further outward than the shape display portion (50) when viewed from above.

According to the eighth state of this disclosure, a substrate (1C) recorded in any of the first to sixth states is provided, wherein: The conductive layer (20) has a plurality of terminal electrode portions (27) not covered by the solder resist (30) when viewed from above; The solder pad (22C) is the portion of the uncovered portion (21) surrounded by an imaginary straight line connecting the outer edges of the plurality of terminal electrode portions (27) when viewed from above; The enlarged portion (23C) is located further outward than the imaginary straight line connecting the plurality of terminal electrode portions (27) when viewed from above.

According to the ninth state pattern disclosed herein, a module (100) is provided, comprising: a substrate (1) recorded in any of the first to eighth state patterns; and an electronic component (110) connected to the solder pad (22), at least a portion of the enlargement (23) being positioned offset from the electronic component (110) in a top view. [Industrial Applicability]

The substrate disclosed herein can supply more solder to the pads, thus making it useful as a substrate for mounting surface mount components, such as power semiconductors or LSIs.

1. 1A-1C: Substrate 10: Substrate Layer 20: Conductive Layer 20a: Lower Surface 20b: Upper Surface 21: Non-coated Part 22. 22C: Solder Pad 22a: Surface 221: Outer Edge 222: Through Hole 23. 23A-23C: Enlarged Part 23a: Surface 24. 24C: Linear Part 25: Branch Part 25C: First Branch Part 25a: Base End 25b: End Part 26: Second Branch Part 27: Terminal Electrode Part 30: Solder Resist 31: Hole Part 32: Terminal Opening Part 40: Plating Film 50: Outline Display Part 100: Module 110: Electronic Component 110a: Bottom surface 111: Heat dissipation electrode 120: Solder D1, D2: Dimensions PS1: Solder paste application area/region PS2: Solder paste application area/region VL: Imaginary line X, Y, Z: Direction

Figure 1 is a plan view of the substrate according to the first embodiment of this disclosure. Figure 2 is a cross-sectional view of the substrate of Figure 1 along line II-II. Figure 3 is a plan view of a module including the substrate of Figure 1. Figure 4 is a cross-sectional view of the module of Figure 3 along line IV-IV. Figure 5 is a plan view of the substrate according to the second embodiment of this disclosure. Figure 6 is a plan view of the substrate according to the third embodiment of this disclosure. Figure 7 is a plan view of the substrate according to the fourth embodiment of this disclosure.

1:Substrate

10: Substrate Layer

20:Conductive layer

20b: Top surface

21: Uncovered part

22: Welding pad

22a: Surface

221: Outer edge

23: Expanded Department

23a: Surface

24: Linear section

27: Terminal electrode section

30: Solder resist

31: Hole section

32: Terminal opening section

40: Coating

50: Exterior Display

D1, D2: Dimensions

PS1: Solder paste application area/area

PS2: Solder paste application area/area

X, Y, Z: Direction (X, Y, Z: Direction)

Claims (6)

A substrate includes: a substrate layer; a conductive layer deposited on the substrate layer; and a solder resist deposited on the conductive layer such that the conductive layer is sandwiched between the conductive layer and the substrate layer, the conductive layer has an uncovered portion, viewed from the stacking direction of the substrate layer, the conductive layer, and the solder resist, not covered by the solder resist in a top view, the uncovered portion has a solder pad for connecting to an electronic component, and an extension extending from the solder pad in a top view, the extension has at least one linear portion that is linear in shape in a top view and one or more branch portions extending linearly from the linear portion in a top view, and At least one of the branches has a base end connected to the linear portion and an end portion, i.e., a terminal portion, opposite to the base end end. The branch extends in a manner that approaches the solder pad in the extending direction of the linear portion from the terminal portion toward the base end end. The substrate as claimed in claim 1, wherein a coating is provided on the surface of the enlarged portion. The substrate as claimed in claim 1, wherein the solder pad is provided with a through hole that extends through the conductive layer along the stacking direction. The substrate as described in claim 1 has a shape display portion, the shape display portion is deposited on the solder resist such that the solder resist is sandwiched between the solder resist layer and the conductive layer, and is formed, in plan view, along the shape of the electronic component when connected to the uncovered portion, the solder pad is the portion of the uncovered portion that is surrounded by the shape display portion in plan view, the enlarged portion is located further outward than the shape display portion in plan view. The substrate as described in claim 1, wherein the conductive layer has a plurality of terminal electrodes not covered by the solder resist when viewed from above; the solder pad is a portion of the uncovered portion surrounded by an imaginary straight line connecting the outer edges of the plurality of terminal electrodes when viewed from above; the enlarged portion is located further outwards from the imaginary straight line connecting the plurality of terminal electrodes when viewed from above. A module comprising: a substrate as described in any one of claims 1 to 5; and an electronic component connected to the solder pad, at least a portion of the enlargement being positioned offset from the electronic component in a top view.