JP7144732B2 - laminated substrate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laminated substrate having elements arranged in an insulating base material.

Conventionally, there has been known a laminated substrate in which elements are arranged in an insulating base material for the purpose of high-density mounting of elements and miniaturization of the substrate (see, for example, Patent Document 1).

JP-A-2003-86949

However, it is assumed that the elements arranged in the insulating base material generate heat during operation, and if the heat is trapped in the insulating base material, there is a risk of malfunction of the elements and electric circuits. In this case, it is conceivable to provide, for example, radiating fins on the surface of the laminated substrate in the vicinity of the elements. Otherwise, heat dissipation may be poor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laminated substrate that can promote heat dissipation of elements even when the elements are arranged in an insulating base material.

In the invention according to claim 1, the laminated substrate is a laminated substrate in which an element is arranged in an insulating base material, the plural resin layers serving as the insulating base material, the elements arranged between the resin layers, a metal heat dissipation layer provided in contact with the element and having at least one end exposed to the side surface of the laminated base material.

If the element placed inside the insulating base generates heat during operation, the heat may be trapped inside the insulating base because there is no contact with the outside air and the insulating base restricts heat transfer. There is If the heat is trapped in the insulating base material, there is a risk of malfunction of the element or an electric circuit using the element. In this case, for example, by providing a heat-dissipating member on the surface of the laminated substrate and arranging a heat-transfer member that penetrates the insulating base material, it is possible to promote heat dissipation to the outside, but the heat-transfer member must be large. In addition, in order to achieve high-density mounting and miniaturization, a configuration that requires an installation space on the surface of the laminated substrate is not preferable.

Therefore, a heat dissipation layer is provided which is in contact with the element and has at least one end exposed to the side surface of the laminated base material. As a result, the heat of the element that has moved to the heat dissipation layer is released to the outside of the laminated substrate when the heat dissipation layer is cooled by the outside air, since the end of the heat dissipation layer is exposed to the side surface of the laminated base material. It contributes greatly to the release of heat. In addition, since the heat dissipation layer is made of metal, the heat of the element is transferred to the heat dissipation layer more quickly than in the case of the insulating base material, so that the heat is prevented from remaining in the laminated substrate. Therefore, even when the element is arranged in the insulating base material, the heat dissipation of the element can be promoted.

In the second aspect of the present invention, the end portion of the heat dissipation layer exposed on the side surface of the laminated substrate is formed on an inclined surface that is inclined with respect to the lamination direction of the laminated substrate. Thereby, even if the thickness of the heat dissipation layer is the same, the area exposed to the outside can be increased, and the heat dissipation efficiency can be improved.

In the third aspect of the invention, the heat dissipation layer has an end exposed on the side surface of the laminated substrate formed in a vertical plane along the stacking direction, and the exposed end is below the heat dissipation layer. is located inside the end of the resin layer arranged in the . As a result, a step is formed between the heat radiating layer and the upper surface of the lower resin layer, and a fillet of a coating agent for rust prevention and anticorrosion is formed on the step. As a result, the thickness of the coating agent is increased as compared with the case where there is no step, and the rust prevention and antiseptic properties can be improved.

In the fourth aspect of the invention, the exposed end of the heat dissipation layer is located outside the end of the resin layer disposed above the heat dissipation layer. As a result, not only the side surface of the heat dissipation layer but also the surface located outside the upper resin layer greatly contributes to heat dissipation, and heat dissipation can be further improved.

FIG. 4 is a diagram schematically showing a configuration example of a laminated substrate according to an embodiment; A diagram schematically showing an example of a lamination mode of a laminated substrate. FIG. 1 schematically shows another configuration example of the laminated substrate; FIG. 2 schematically shows another configuration example of the laminated substrate; FIG. 3 schematically shows another configuration example of the laminated substrate; A diagram schematically showing another configuration example of the heat dissipation layer FIG. 4 schematically shows another configuration example of the laminated substrate; Diagram 1 schematically showing a configuration example of the end portion of the heat dissipation layer Diagram 2 schematically showing a configuration example of the end portion of the heat dissipation layer FIG. 5 schematically shows another configuration example of the laminated substrate; A diagram schematically showing an example of a method of forming an inclined surface on a laminated substrate.

Hereinafter, embodiments will be described with reference to the drawings.
As shown in FIG. 1, the laminated substrate 1 of the present embodiment includes a plurality of resin layers 2 which are insulating base materials, elements 3 arranged between the resin layers 2, and elements 3 provided in contact with the elements 3. and a heat dissipation layer 4 made of metal. The laminated substrate 1 has side surfaces that are vertical along the lamination direction, and is generally formed in a rectangular parallelepiped shape as a whole. The number of resin layers 2 and heat dissipation layers 4 and the number and arrangement of elements 3 are examples, and are not limited to those shown in FIG.

The resin layer 2 is made of, for example, a thermoplastic resin containing polyetheretherketone resin or polyetherimide resin, and is deformed by heating and pressing. A circuit pattern, electrodes, etc. (not shown) are formed by etching on one or both surfaces of the resin layer 2 . Moreover, at least one resin layer 2 is provided with an accommodating portion 2a that is recessed in a part of the surface. However, the resin layer 2 may have only a circuit pattern without forming the accommodating portion 2a, or the accommodating portion 2a may have a shape penetrating the resin layer 2. .

Elements 3 forming a circuit, vias 5 (see FIG. 5) electrically connecting the upper layer side and the lower layer side in a laminated state, and the like are arranged in the accommodating portion 2a. In FIG. 1, for the sake of simplification of explanation, illustration of the vias 5 is omitted, and only the housing portion 2a for housing the element 3 is shown. This element 3 can employ, for example, a resistor, a capacitor, or a semiconductor device. Therefore, these elements 3 may generate heat when energized.

The heat dissipation layer 4 is made of a metal such as copper or aluminum. exposed at the end of the In this embodiment, the heat dissipation layer 4 is exposed to the outside on four side surfaces of the laminated substrate 1 formed in a rectangular parallelepiped shape.

Although it is desirable that the heat dissipation layer 4 is in direct contact with the element 3, a slight space may exist or an extremely thin resin may be interposed as long as the heat can be transferred. That is, in the present invention, the state in which the element 3 and the heat dissipation layer 4 are in contact means that the element 3 and the heat dissipation layer 4 are arranged at a distance that enables heat conduction.

In this embodiment, the surface of the heat dissipation layer 4 is coated with the same resin material as the resin layer 2 except for the range in contact with the element 3 . This is because the circuit patterns are provided on the resin layer 2 as described above, so that the circuit patterns and the circuit patterns in the vertical direction are not short-circuited.

As shown in FIG. 2, the laminated substrate 1 having such a configuration includes one or more resin layers 2 accommodating the elements 3 and two resin layers corresponding to the elements 3 that require heat dissipation. One or more provided heat dissipation layers 4 are laminated, and the resin layer 2 is deformed by heating and pressurizing the entire laminated state, filling the gaps between the elements 3 and the gaps between the resin layers 2. It is manufactured by a manufacturing method that adopts a batch lamination process method using an insulating base material. The manufactured substrate is conformally coated with fluorine on its surface and side surfaces where the heat dissipation layer 4 is exposed in order to avoid corrosion due to sulfur, for example.

Next, the operation and effects of the above configuration will be described.
When the element 3 placed inside the insulating base generates heat during operation, the heat is trapped inside the insulating base because there is no contact with the outside air and because the insulating base restricts heat transfer. end up If the heat is trapped in the insulating base material, the element 3 and an electric circuit using the element 3 may malfunction. Further, it is considered possible to promote heat dissipation by providing a heat-dissipating member on the surface of the laminated substrate 1 and arranging a heat-transfer member penetrating the laminated substrate 1, but it is difficult to increase the size of the heat-transfer member. In order to achieve high-density mounting and miniaturization, it is not preferable to provide a heat-dissipating member on the surface of the laminated substrate 1, which requires an installation space.

Therefore, in this embodiment, the heat dissipation layer 4 is provided in contact with the element 3 and has at least one end exposed at the end of the laminated base material. As a result, the heat generated by the element 3 can be efficiently transferred to the heat dissipation layer 4, and since a part of the heat dissipation layer 4 is exposed to the outside, the heat is dissipated from the heat dissipation layer 4 by the outside air. Prompted. As a result, the heat of the element 3 can be efficiently released to the outside. Therefore, even when the element 3 is arranged inside the insulating base material, the heat dissipation of the element 3 can be promoted.

In this case, it is possible to suppress the heat from the element 3 from staying in the insulating base material, so that it is possible to reduce the risk of malfunction of the element 3 and an electric circuit using the element 3 . In addition, unlike the case where the laminated substrate 1 is provided with heat radiation fins or the like, the space on the mounting surface is not reduced, so high-density mounting and miniaturization are not impaired.

In addition, by bringing the heat dissipation layer 4 into contact with the entire upper surface of the element 3 as in the embodiment, the heat of the element 3 can be transferred to the heat dissipation layer 4 efficiently and quickly, and the heat is accumulated in the laminated substrate 1. The fear can be reduced.

In addition, when the four sides of the laminated substrate 1 are exposed as in the embodiment, the area available for heat dissipation is the length of the four sides of the laminated substrate 1 x the thickness of the heat dissipation layer 4, and the heat dissipation layer 4 is relatively large. Even if it is thin, it can be expected that a sufficient heat dissipation area can be secured. As a result, the thickness of the laminated substrate 1 is not excessively increased, the weight of the laminated substrate is not excessively increased, and furthermore, it is necessary to secure a space for heat dissipation on the surface of the laminated substrate 1. Since heat dissipation from the element 3 can be promoted without reducing the size, high-density mounting and miniaturization are not impaired.

However, if the required heat dissipation area can be ensured, it is also possible to adopt a configuration in which one side, two sides, or three sides of the laminated substrate 1 are exposed. In this case, it is possible to reduce the area occupied by the heat dissipation layer 4 in the plan view of the laminated substrate 1, and the provision of the heat dissipation layer 4 can suppress the restriction of the layout of the circuit pattern and the connection position in the vertical direction.

Further, by the manufacturing method described above, it is possible to manufacture the laminated substrate 1 that can promote the heat dissipation of the elements 3 even when the elements 3 are arranged in the insulating base material.
Now, it is assumed that the elements 3 incorporated in the laminated substrate 1 do not necessarily have the same shape, but have different heights in the lamination direction. In that case, as shown in FIG. 3, by adjusting the depth of the accommodating portion 2a in advance so that the upper ends of the elements 3 are aligned, the elements 3 having different heights are brought into contact with one heat dissipation layer 4. can be configured. As a result, even the elements 3 having different heights can be dissipated by one heat dissipation layer 4, and the structure of the laminated substrate 1 can be simplified.

Moreover, when the heights of the elements 3 in the stacking direction are different, a plurality of heat dissipation layers 4 can be provided as shown in FIG. In this case, by adding a spacer or a resin layer 2 functioning as a circuit pattern to compensate for the difference in height, it is possible to prevent the thickness from being shifted when stacked.

Moreover, the heat dissipation layer 4 does not necessarily have to be a single plate covering the entire area of the laminated substrate 1. For example, as shown in FIG. When passing through the via 5 , a through hole or a notch may be formed at the position of the via 5 so that the heat dissipation layer 4 does not interfere with the via 5 . As a result, it is possible to easily perform connection in the vertical direction, which is assumed when high-density mounting is performed.

In this case, as shown in FIG. 6, the heat dissipation layer 4 has a frame-like shape along the outer edge of the laminated substrate 1, and tabs 4a are provided inside the frame to enable contact with the element 3. be able to. For example, a solid ground provided on a so-called printed circuit board requires a large area to stabilize the potential. On the other hand, in the case of the heat dissipation layer 4, it is considered that the heat dissipation can be promoted more as the portion exposed from the insulating base material is larger than the area in plan view.

In addition, since the wiring space for the circuit pattern is generally provided inside the edge of the laminated substrate 1 , the edge of the laminated substrate 1 is considered not to have the circuit pattern and the vias 5 . Further, it is assumed that a connector or the like is provided on the edge of the front or back surface of the laminated substrate 1, but it is assumed that such members are rarely provided on the inner layer side, that is, the side surface of the laminated substrate 1.

Therefore, the vicinity of the outer edge of the laminated substrate 1 is considered to be a space that can be used without considering other members and circuits, in other words, a space that is less likely to affect other members and circuits. Therefore, by forming the heat dissipation layer 4 in the shape of a frame along the periphery of the laminated substrate 1 and providing tabs 4a in contact with the elements 3 that require heat dissipation, the inside of the frame can be used as the layout position of the circuit pattern and the vias 5. Therefore, the heat dissipation layer 4 can be provided while securing a large exposed area without affecting the wiring and connections significantly.

Up to this point, the laminated substrate 1 having a rectangular parallelepiped shape has been described, but the laminated substrate 1 can be formed in a stepped manner, as shown in FIG. In this case, as shown in the region (R1) in FIG. 7, the end portion of the heat dissipation layer 4 and the end portion of the resin layer 2 disposed thereabove may be flush with each other. As shown in R2), it is also possible to adopt a configuration in which the end portion of the resin layer 2 disposed above the end portion of the heat dissipation layer 4 is located inside.

By forming the steps in this way, the corrosion resistance of the laminated substrate 1 can be improved. That is, as shown in FIG. 8, which is an enlarged view of the region (R1), and FIG. 9, which is an enlarged view of the region (R2), when a conformal coat of fluorine is applied, for example, the end portion of the heat dissipation layer 4 is arranged downward. Since it is positioned inside the end of the resin layer 2 where it is located, a fillet 6 of the coating agent is formed in the step portion, the coating thickness is increased, and the corrosion resistance is improved. Further, for example, in the case of the region (R2), the end of the heat dissipation layer 4 is located outside the end of the resin layer 2 disposed above, so that the upper surface thereof also contributes to heat dissipation. As a result, the heat dissipation of the element 3 can be promoted further.

Moreover, as shown in FIG. 10, the laminated substrate 1 can be formed in a trapezoidal shape in which the upper side in the lamination direction becomes gradually smaller when viewed from the side. In this case, the end portion of the heat dissipation layer 4 forms an inclined surface obliquely inclined with respect to the stacking direction. In this case, the area exposed from the laminated substrate 1 is larger than in the case of the vertical plane shown in FIG. can be done.

In this case, the trapezoidal heat-dissipating layer 4 and the resin layer 2 can be laminated in advance, but as shown in FIG. By cutting the four sides along the imaginary line (Lc) at a predetermined angle, the trapezoidal laminated substrate 1 can be finally formed. In this case, even if the ends are covered with excess resin when the resin layer 2 is deformed, the heat dissipation layer 4 can be easily exposed to the outside by cutting the edges.

In the embodiment, the circuit pattern is provided in the resin layer 2 in which the housing portion 2a is formed, but the circuit pattern is formed in a relatively thin separate resin layer 2, and the housing portion 2a is formed. It can be configured to be laminated on the resin layer 2 . As a result, although it is necessary to form a dedicated resin layer 2 for the element 3 that is expected to change depending on the specifications, the circuit pattern can be wired using the common resin layer 2, which improves productivity. We can expect improvement.

In the embodiment, a manufacturing method employing a batch lamination process technique was exemplified, but the manufacturing method can also be applied to a technique of laminating and adhering by applying an adhesive or the like.

In the drawings, 1 indicates a laminated substrate, 2 a resin layer, 3 an element, and 4 a heat dissipation layer.

Claims (3)

A laminated substrate in which an element is arranged in an insulating base material,
a resin layer that serves as the insulating base material;
an element disposed between the resin layers;
a metal heat dissipation layer provided in contact with the element and having at least one end exposed to a side surface of the laminated substrate ;
The heat-dissipating layer has a side portion of the end portion exposed on the side surface of the laminated substrate formed along the stacking direction, and the side portion of the resin layer is arranged below the heat-dissipating layer. 1. A laminated substrate positioned inside an end portion, forming a step that is relatively small on the upper side in the lamination direction, and the side portion exposed at the portion of the step is covered with a fillet . The exposed end portion of the heat dissipation layer is positioned outside the end portion of the resin layer disposed above the heat dissipation layer, and the upper surface portion of the exposed end portion is partially exposed. and forming a stepped step whose upper side in the stacking direction is relatively smaller, and both the upper surface portion and the side portion exposed at the stepped portion are covered with fillets. Item 2. The laminated substrate according to item 1. 3. The laminated substrate according to claim 1, wherein the side surface portion of the end portion of the heat dissipation layer exposed on the side surface of the laminated substrate is formed on an inclined surface inclined with respect to the lamination direction of the laminated substrate. .

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