Patent Description:
Patent Document <NUM> discloses a heat-dissipating structure in which a heating element such as a semiconductor package and a heat dissipator such as a heat sink are brought into close contact with each other with interposition of a multilayer resin sheet and heat generated from the heating element is dissipated through the multilayer resin sheet. Patent Document <NUM> discloses a similar heat-dissipating structure.

Patent Document <NUM>: <CIT> Patent Document <NUM>: <CIT>.

In the heat-dissipating structure, for example, when a multilayer resin sheet is attached to a plate surface of a printed circuit board having the plate surface provided with a plurality of patterns having large irregularities and different potentials, a void may be formed between the printed circuit board and the multilayer resin sheet. When such voids are formed, insulation properties between the printed circuit board and the multilayer resin sheet may be deteriorated.

An object of the present disclosure is to provide a heat-dissipating structure having high insulation properties.

A heat-dissipating structure according to an aspect of the present disclosure is a heat-dissipating structure configured to dispose between a heating element and a heat dissipation member, the heat dissipation being configured to dissipate heat generated by the heating element, the heat-dissipating structure including:.

The heat-dissipating structure includes at least one heat transfer portion including a plate-shaped heat transfer member and a conductive layer. The heat transfer member is provided between the board and the resin layer and extending along the board. The conductive layer is provided between the board and the resin layer and across the board and the heat transfer member, and partially disposed between the heat transfer member and the resin layer. With this configuration, since the void formed by the board, the heat transfer member, and the resin layer can be covered with the conductive layer from the resin layer side, for example, when the heating element is an electronic component, occurrence of partial discharge caused by the void can be suppressed. As a result, a heat-dissipating structure having high insulation properties can be achieved.

Hereinafter, an example of the present disclosure will be described with reference to the accompanying drawings. It should be noted that in the following description, terms indicating specific directions or positions (for example, terms including "upper", "lower", "right", and "left") are used as necessary, but using these terms is to facilitate understanding of the present disclosure with reference to the drawings, and the technical scope of the present disclosure is not limited by the meaning of the terms. Furthermore, the drawings are schematic, and ratios and the like of the respective dimensions do not necessarily match those of actual ones.

As shown in <FIG>, a heat-dissipating structure <NUM> according to an embodiment of the present disclosure is configured to dispose between a heating element <NUM> and a heat dissipation member <NUM>, the heat dissipation member being configured to dissipate heat generated by the heating element <NUM>. The heating element <NUM> includes, for example, an electronic component such as a semiconductor, and the heat dissipation member <NUM> includes, for example, a heat sink.

As shown in <FIG>, the heat-dissipating structure <NUM> includes a board <NUM>, a resin layer <NUM> attached to the board <NUM>, and a heat transfer portion provided between the board <NUM> and the resin layer <NUM>. The heat transfer portion is configured to transfer heat generated by the heating element <NUM> to the heat dissipation member <NUM> through the resin layer <NUM>. In the present embodiment, two heating elements <NUM> are attached to the board <NUM>, and the heat-dissipating structure <NUM> includes two heat transfer portions (hereinafter, referred to as a first heat transfer portion <NUM> and a second heat transfer portion <NUM>) corresponding to the respective heating elements <NUM>.

The board <NUM> is, for example, a printed circuit board including a copper foil and having a thickness of <NUM> or more, and includes a first surface <NUM> to which the heating element <NUM> is attached and a second surface <NUM> disposed on an opposite side from the first surface <NUM> in a thickness direction of the board as shown in <FIG>. The resin layer <NUM> is attached to the second surface <NUM>.

The resin layer <NUM> is made of, for example, silicone containing an inorganic filler, and has a thickness of <NUM> or more. The resin layer <NUM> includes a first end and a second end in a thickness direction of the resin layer, the first end being attached to the heating element <NUM> and the second end being attached to the heat dissipation member <NUM>.

The heat transfer portions <NUM>, <NUM> include plate-shaped heat transfer members <NUM>, <NUM> and conductive layers <NUM>, <NUM>, respectively.

The heat transfer member <NUM>, <NUM> is, for example, made of copper and formed by etching. In the present embodiment, the heat transfer member <NUM>, <NUM> has, for example, a substantially rectangular film shape having a thickness of <NUM> or less, is provided between the board <NUM> and the resin layer <NUM>, and extends along the second surface <NUM> of the board <NUM> as shown in <FIG>. The heat transfer member <NUM>, <NUM> is connected to the heating elements <NUM> through the heat transfer layer <NUM>, <NUM> extending through the board <NUM> in the thickness direction.

The conductive layer <NUM>, <NUM> is made of, for example, copper, silver, or graphite, and is formed by plating, sputtering, or lamination. In the present embodiment, the conductive layer <NUM>, <NUM> has a thickness of <NUM> or less, and as shown in <FIG>, is provided between the board <NUM> and the resin layer <NUM> and across the board <NUM> and the heat transfer member <NUM>, <NUM>, and partially disposed between the heat transfer member <NUM>, <NUM> and the resin layer <NUM>. As shown in <FIG>, the conductive layer <NUM>, <NUM> is disposed to cover an entire peripheral edge of the heat transfer member <NUM>, <NUM>, and covers an entire void <NUM> formed by the board <NUM>, the heat transfer member <NUM>, and the resin layer <NUM> from the resin layer <NUM> side.

Here, regarding the heat-dissipating structure <NUM> of the present embodiment, influence of the thicknesses and elastic moduli of the conductive layer <NUM>, <NUM> and the resin layer <NUM> on adhesion between the conductive layer <NUM>, <NUM> and board <NUM> and between the resin layer <NUM> and board <NUM> was examined. Specifically, regarding a plurality of heat-dissipating structures <NUM> including the conductive layer <NUM>, <NUM> having a thickness of <NUM> and an elastic modulus of <NUM> Gpa and the resin layer <NUM> having a different thickness and elastic modulus, in a state where the resin layer <NUM> was pressed toward the board <NUM> until the thickness thereof reached <NUM>%, whether the conductive layer <NUM>, <NUM> and resin layer <NUM> and the board <NUM> were in contact with each other or not was measured.

<FIG> shows the heat-dissipating structure <NUM> when the ratio of the elastic modulus of the resin layer <NUM> to the elastic modulus of the conductive layer <NUM>, <NUM> is <NUM>/<NUM>,<NUM>, and the ratio of the thickness of the resin layer <NUM> to the thickness of the conductive layer <NUM>, <NUM> is <NUM>. In the heat-dissipating structure <NUM> in <FIG>, the conductive layer <NUM>, <NUM> and resin layer <NUM> and the board <NUM> were in contact with each other in many portions, and high adhesion was obtained.

<FIG> shows the heat-dissipating structure <NUM> when a ratio of the elastic modulus of the resin layer <NUM> to the elastic modulus of the conductive layer <NUM>, <NUM> is <NUM>/<NUM>,<NUM>, and a ratio of the thickness of the resin layer <NUM> to the thickness of the conductive layer <NUM>, <NUM> is <NUM>. In the heat-dissipating structure <NUM> in <FIG>, the conductive layer <NUM>, <NUM> and resin layer <NUM> and the board <NUM> were in contact with each other in many portions, and high adhesion was obtained.

<FIG> shows the heat-dissipating structure <NUM> when a ratio of the elastic modulus of the resin layer <NUM> to the elastic modulus of the conductive layer <NUM>, <NUM> is <NUM>/<NUM>,<NUM>, and a ratio of the thickness of the resin layer <NUM> to the thickness of the conductive layer <NUM>, <NUM> is <NUM>. In the heat-dissipating structure <NUM> in <FIG>, the conductive layer <NUM>, <NUM> and the board <NUM> were in contact with each other in many portions to secure sufficient adhesion, but a gap <NUM> was formed in many portions between the resin layer <NUM> and the board <NUM>, and sufficiently high adhesion was not obtained.

<FIG> shows the heat-dissipating structure <NUM> when a ratio of the elastic modulus of the resin layer <NUM> to the elastic modulus of the conductive layer <NUM>, <NUM> is <NUM>/<NUM>,<NUM>, and a ratio of the thickness of the resin layer <NUM> to the thickness of the conductive layer <NUM>, <NUM> is <NUM>. In the heat-dissipating structure <NUM> in <FIG>, the conductive layer <NUM>, <NUM> and the board <NUM> were in contact with each other in many portions to secure sufficient adhesion, but a gap <NUM> was formed in many portions between the resin layer <NUM> and the board <NUM>, and high adhesion was not obtained.

<FIG> shows the heat-dissipating structure <NUM> when a ratio of the elastic modulus of the resin layer <NUM> to the elastic modulus of the conductive layer <NUM>, <NUM> is <NUM>/<NUM>,<NUM>, and a ratio of the thickness of the resin layer <NUM> to the thickness of the conductive layer <NUM>, <NUM> is <NUM>. In the heat-dissipating structure <NUM> in <FIG>, a gap <NUM> was formed in many portions between the resin layer <NUM> and the board <NUM>, and a gap <NUM> was formed between the conductive layer <NUM>, <NUM> and the board <NUM>, and sufficiently high adhesion was not obtained.

From the above investigation results, it has been found that by configuring the heat-dissipating structure <NUM> so that a ratio of the elastic modulus of the resin layer <NUM> to the elastic modulus of the conductive layer <NUM>, <NUM> is <NUM>/<NUM>,<NUM> or less, and a ratio of the thickness of the resin layer <NUM> to the thickness of the conductive layer <NUM>, <NUM> is <NUM> or more, adhesion of the conductive layer <NUM>, <NUM> and the resin layer <NUM> to the board <NUM> can be enhanced.

According to the heat-dissipating structure <NUM>, the following effects can be exerted.

The heat-dissipating structure <NUM> includes a heat transfer portion <NUM> including: a plate-shaped heat transfer member <NUM>, <NUM> and a conductive layer <NUM>, <NUM>. The heat transfer member <NUM>, <NUM> is provided between the board <NUM> and the resin layer <NUM> and extending along the board <NUM>. The conductive layer <NUM>, <NUM> is provided between the board <NUM> and the resin layer <NUM> and across the board <NUM> and the heat transfer member <NUM>, <NUM>, the conductive layer <NUM>, <NUM> being partially disposed between the heat transfer member <NUM>, <NUM> and the resin layer <NUM>. With this configuration, since a void <NUM> formed by the board <NUM>, the heat transfer member <NUM>, <NUM>, and the resin layer <NUM> can be covered with the conductive layer <NUM>, <NUM> from the resin layer <NUM> side, for example, when the heating element <NUM> is an electronic component, occurrence of partial discharge caused by the void <NUM> can be suppressed. As a result, a heat-dissipating structure <NUM> having high insulation properties can be achieved.

A ratio of the elastic modulus of the resin layer <NUM> to the elastic modulus of the conductive layer <NUM>, <NUM> is <NUM>/<NUM>,<NUM> or less, and a ratio of the thickness of the resin layer <NUM> to the thickness of the conductive layer <NUM>, <NUM> is <NUM> or more. With this configuration, adhesion of the conductive layer <NUM>, <NUM> and the resin layer <NUM> to the board <NUM> can be enhanced. As a result, for example, when the heating element <NUM> is an electronic component, occurrence of partial discharge caused by the void <NUM> is suppressed, and a heat-dissipating structure <NUM> with high insulation properties can be achieved.

The conductive layer <NUM>, <NUM> is configured to cover the entire void <NUM>, that is, to cover an entire peripheral edge of the heat transfer member <NUM>, <NUM>. With this configuration, for example, when the heating element <NUM> is an electronic component, occurrence of partial discharge caused by the void <NUM> can be more reliably suppressed.

According to the heat-dissipating structure <NUM>, following configuration can also be made.

The number of heat transfer portions may be one, or three or more.

Each of the conductive layer <NUM>, <NUM> and the resin layer <NUM> may be configured so that a ratio of the elastic modulus of the resin layer <NUM> to the elastic modulus of the conductive layer <NUM>, <NUM> is larger than <NUM>/<NUM>,<NUM>, or each of the conductive layer <NUM>, <NUM> and the resin layer <NUM> may be configured so that a ratio of the thickness of the resin layer <NUM> to the thickness of the conductive layer <NUM>, <NUM> is less than <NUM>.

The conductive layer <NUM>, <NUM> is not limited to the case of being configured to cover the entire peripheral edge of the heat transfer member <NUM>, <NUM>, and may be configured to cover a part of the peripheral edge of the heat transfer member <NUM>, <NUM> as shown in <FIG>. In the heat-dissipating structure <NUM> in <FIG>, the conductive layer <NUM> of the first heat transfer portion <NUM> is disposed to cover a peripheral edge of the heat transfer member <NUM> of the first heat transfer portion <NUM> closest to the heat transfer member <NUM> of the second heat transfer portion <NUM> in the direction along the board <NUM>. As described above, by disposing the respective conductive layers <NUM>, <NUM> to cover voids <NUM> closest to each other in the direction along the board <NUM>, occurrence of partial discharge caused by the voids <NUM> can be more reliably suppressed.

That is, the heat-dissipating structure <NUM> can adopt any configuration capable of covering the void <NUM> with the conductive layer <NUM>, <NUM>.

As described above, various embodiments in the present disclosure have been described in detail with reference to the drawings. Lastly, various aspects of the present disclosure will be described. It should be noted that in the following description, as an example, reference numerals are also added.

A heat-dissipating structure <NUM> according to a first aspect of the present disclosure is a heat-dissipating structure <NUM> configured to dispose between a heating element <NUM> and a heat dissipation member <NUM>, the heat dissipation being configured to dissipate heat generated by the heating element <NUM>, the heat-dissipating structure <NUM> including:.

In the heat-dissipating structure <NUM> according to a second aspect of the present disclosure, a ratio of an elastic modulus of the resin layer <NUM> to an elastic modulus of the conductive layer <NUM>, <NUM> is <NUM>/<NUM>,<NUM> or less, and a ratio of a thickness of the resin layer <NUM> to a thickness of the conductive layer <NUM>, <NUM> is <NUM> or more.

In the heat-dissipating structure <NUM> according to a third aspect of the present disclosure, the conductive layer <NUM>, <NUM> is configured to cover an entire peripheral edge of the heat transfer member <NUM>, <NUM>.

In the heat-dissipating structure <NUM> according to a fourth aspect of the present disclosure, the at least one heat transfer portion includes a first heat transfer portion <NUM> and a second heat transfer portion <NUM>, and
the conductive layer <NUM> of the first heat transfer portion <NUM> is disposed to cover a peripheral edge of the heat transfer member <NUM> of the first heat transfer portion <NUM> closest to the heat transfer member <NUM> of the second heat transfer portion <NUM> in a direction along the board <NUM>.

Appropriately combining any embodiment or modification out of the various embodiments or modifications allows the effect of each of the embodiment or modification to be exhibited. In addition, a combination of embodiments, a combination of examples, or a combination of an embodiment and an example is possible, and a combination of features of different embodiments or examples is also possible.

The present disclosure has been sufficiently described in connection with the preferred embodiments with reference to the accompanying drawings.

Claim 1:
A heat-dissipating structure (<NUM>) configured to dispose between a heating element (<NUM>) and a heat dissipation member (<NUM>), the heat dissipation member (<NUM>) being configured to dissipate heat generated by the heating element (<NUM>), the heat-dissipating structure (<NUM>) comprising:
a board (<NUM>) configured to be attached to the heating element (<NUM>);
a resin layer (<NUM>) provided between the board (<NUM>) and the heat dissipation member (<NUM>), the resin layer (<NUM>) being attached to the board (<NUM>); and
at least one heat transfer portion configured to transfer heat generated by the heating element (<NUM>) to the heat dissipation member (<NUM>) through the resin layer (<NUM>), wherein
the at least one heat transfer portion includes:
a heat transfer member (<NUM>, <NUM>), which is plate-shaped, provided between the board (<NUM>) and the resin layer (<NUM>), the heat transfer member (<NUM>, <NUM>) extending along the board (<NUM>), and
a conductive layer (<NUM>, <NUM>) provided between the board (<NUM>) and the resin layer (<NUM>) and across the board (<NUM>) and the heat transfer member (<NUM>, <NUM>), the conductive layer (<NUM>, <NUM>) being partially disposed between the heat transfer member (<NUM>, <NUM>) and the resin layer (<NUM>).