Patent ID: 12238852

DETAILED DESCRIPTION

Implementations of the disclosure will now be described, by way of embodiments only, with reference to the drawings. It should be noted that the embodiments and the features of the present disclosure can be combined without conflict. Specific details are set forth in the following description to make the present disclosure to be fully understood. The embodiments are only some and not all the embodiments of the present disclosure. Based on the embodiments of the present disclosure, other embodiments obtained by a person of ordinary skill in the art without creative efforts shall be within the scope of the present disclosure.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terms used herein in the specification of the present disclosure are only for describing the embodiments, and are not intended to limit the present disclosure. The term “and/or” as used herein includes any combination of one or more related items.

In the embodiments of the present disclosure, and not as a limitation of the present disclosure, the term “connection” used in the specification and claims of the present disclosure is not limited to physical or mechanical connection, no matter direct connection or indirect connection. The terms of “up”, “down”, “above”, “below”, “left”, “right”, etc., are only used to indicate the relative position relationship. When the absolute position of a described element changes, the relative positions correspondingly changes.

Referring toFIGS.20and21, a method for manufacturing a circuit board is disclosed in one embodiment. The method is provided by way of example, as there are a variety of ways to carry out the method. The method can begin at block1.

At block1, referring toFIG.1, a first metal layer10is provided.

The first metal layer10defines a first opening11penetrating therethrough. In at least one embodiment, the first opening11may be formed by laser.

The first metal layer10has high mechanical strength and thermal conductivity. In at least one embodiment, the first metal layer10may be made of copper alloy, aluminum alloy, or copper aluminum alloy.

At block2, referring toFIG.2, at least one first receiving groove12and at least one first blind hole13are defined in the first metal layer10.

The first receiving groove12and the first blind hole13defined on a same surface of the first metal layer10. Each of the first receiving groove12and the first blind hole13does not penetrate through the first metal layer10.

In at least one embodiment, each first receiving groove12is positioned between two adjacent first blind holes13.

In at least one embodiment, the first receiving groove12and the first blind hole13may be formed by etching.

At block3, referring toFIG.3, a phase change material is filled in the first receiving groove12to form a first phase change layer20. A solder flux is filled in the first blind hole13to form a solder layer21. Then, a first substrate22is obtained.

In at least one embodiment, the first phase change layer20may be made of paraffin (CnH2n+2), inorganic salt hydrate, or fatty acid. In at least one embodiment, the inorganic salt hydrate includes at least one of disodium phosphate dodecahydrate, calcium nitrate tetrahydrate, and sodium acetate trihydrate. The fatty acid includes at least one of lauric acid and myristic acid.

In at least one embodiment, the first phase change layer20infills the whole first receiving groove12. The solder layer21only fills a bottom of the first blind hole13.

At block4, referring toFIG.4, a second metal layer30and a dielectric layer31disposed on the second metal layer30are provided.

In at least one embodiment, the dielectric layer31may be a peelable film.

The second metal layer30and the first metal layer10may be made of a same material or different materials.

At block5, referring toFIG.5, at least one second opening32and at least one second blind hole33are defined in the dielectric layer31and the second metal layer30.

The second opening32penetrates through the dielectric layer31and the second metal layer30. The second blind hole33penetrates through the dielectric layer31and a portion of the second metal layer30.

In at least one embodiment, the second opening32and the second blind hole33may be formed by laser.

In at least one embodiment, each second opening32is disposed between two adjacent second blind holes33.

At block6, referring toFIG.6, metal is electroplated in the second blind hole33to form a connecting post40.

In at least one embodiment, an end of the connecting post40away from the second metal layer30is substantially flush with a surface of the dielectric layer31away from the second metal layer30.

At block7, referring toFIG.7, the dielectric layer31is removed, causing the end of the connecting post40away from the second metal layer30to protrude from the second metal layer30.

At block8, referring toFIG.8, at least one second receiving groove41is defined in the second metal layer30.

The second receiving groove41and the connecting post40are disposed on a same surface of the second metal layer30, and the second receiving groove41does not penetrate through the second metal layer30. In at least one embodiment, each second receiving grooves41is disposed between two adjacent connecting posts40.

In at least one embodiment, the second receiving groove41may be formed by etching.

At block9, referring toFIG.9, a phase change material is filled in the second receiving groove41to form a second phase change layer23. Then, a second substrate42is obtained.

In at least one embodiment, the second phase change layer23and the first phase change layer20may be made of a same material or different materials.

At block10, referring toFIG.10, the first substrate22and the second substrate42are pressed together, causing the connecting post40to be disposed in the first blind hole13and connected to the solder layer21. Furthermore, the first opening11and the second opening32are aligned with each other to form a first through hole43. The first metal layer10and the second metal layer30are connected to each other to form a heat conductive layer44. The phase change layer20and the second phase change layer23are connected to each other to form a phase change structure24, and the phase change structure24is wrapped by the heat conductive layer44. Then, a heat dissipation substrate50is obtained.

The first through hole43penetrates through the heat dissipation substrate50.

In at least one embodiment, the solder layer21and the connecting post40can fix the first substrate22to the second substrate42.

At block11, referring toFIG.11, two insulating layers60are formed on two opposite surfaces of the heat dissipation substrate50. The insulating layers60also infill the first through hole43.

The insulating layers60can be made of a material selected from epoxy resin, polypropylene (PP), BT resin, polyphenylene oxide (PPO), polyimide (PI), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN).

At block12, referring toFIG.12, a groove61is defined in each of the insulating layers60. A bottom of the groove61corresponds to the heat conductive layer44, and the heat conductive layer44is partially exposed from the groove61.

At block13, referring toFIG.13, an electronic component70is mounted in each groove61through a bonding sheet70. The bonding sheet70is in thermal conduction with the heat conductive layer44.

The bonding sheet70has a high thermal conductivity. In at least one embodiment, the bonding sheet70may be made of silica gel or acrylic resin with high conductivity.

In at least one embodiment, the electronic component71may partially protrude from the insulating layer60.

During working, the heat generated by each electronic component71can be transmitted to the phase change structure24through the bonding sheet70and the heat conductive layer44. The phase change structure24absorbs the heat. Thus, the temperature of the electronic component71can be reduced.

At block14, referring toFIG.14, a single-sided copper-cladding substrate80is disposed on each insulating layer60.

In at least one embodiment, each single-sided copper-cladding substrate80includes a base layer81and a copper foil layer82. The base layer81is between the copper foil layer82and the electronic component71. The portion of the electronic component71protruding from the insulating layer60is embedded in the base layer81.

The base layer81can be made of a material selected from epoxy resin, polypropylene, BT resin, polyphenylene oxide, polyimide, polyethylene terephthalate, and polyethylene naphthalate.

At block15, referring toFIG.15, a second through hole83is defined in each single-sided copper-cladding substrate80and the insulating layer60. A bottom of the second through hole83corresponds to the heat conductive layer44.

At block16, referring toFIG.16, a heat conductive material is filled in each second through hole83to form a heat conductive portion84. The heat conductive portion84is in thermal conduction with the heat conductive layer44.

In at least one embodiment, the heat conductive material may be graphite sheet, heat conductive gel, or silicone. In other embodiments, the heat conductive portion84may also be formed by plating tin in the second through hole.

At block17, referring toFIG.17, a slot85is defined in each single-sided copper-cladding substrate80, a bottom of the slot85corresponds to the electronic component71. A third through hole86corresponding to corresponds to the first through hole43is formed in each single-sided copper-cladding substrate80and the insulating layer60.

In at least one embodiment, a diameter of the slot85decreases in a direction from the single-sided copper-cladding substrate80to the insulating layer60. A diameter of the third through hole86is smaller than a diameter of the first through hole43. The third through hole86sequentially penetrates through the copper foil layer82, the base layer81, the insulating layer60, another base layer81, and another copper foil layer82.

At block18, referring toFIG.18, metal is electroplated on each copper foil layers82to form a copper plating layer90. The copper plating layer90also infills the grooves85and the third through holes86to form a first electric conductive portion91and a second electric conductive portion92, respectively.

At block19, referring toFIG.19, each copper plating layer90and one corresponding copper foil layer82are etched to form a circuit layer93. Then, the circuit board100is obtained. The first electric conductive portion91can electrically connect the circuit layer93to the adjacent electronic component71. The second electric conductive portion92can electrically connect the two circuit layers93together.

The heat generated by the each of the two circuit layers93can be transmitted to the phase change structure24through the heat conductive portion84. The phase change structure24absorbs the heat, thereby reducing the temperature of the circuit layer93.

Moreover, since the heat dissipation substrate50and the electronic component71are embedded in the circuit board100, the overall thickness of the circuit board100can be reduced.

FIG.19illustrates an embodiment of a circuit board100, including a heat dissipation substrate50, two insulating layers60, two bonding sheets70, two electronic components71, two base layers81, and two circuit layers93.

In at least one embodiment, the heat dissipation substrate50includes a first substrate22and a second substrate42. The first substrate22includes a first metal layer10. The first metal layer10defines a first opening11penetrating therethrough. A first receiving groove12and a first blind hole13are also defined in the first metal layer10. The first receiving groove12and the first blind hole13are defined on a same surface of the first metal layer10, and do not penetrate through the first metal layer10.

A first phase change layer20is disposed in the first receiving groove12. A solder layer21is disposed in the first blind hole13. In at least one embodiment, the first phase change layer20fills the whole first receiving groove12, and the solder layer21only fills a bottom of the first blind hole13.

The second substrate42includes a second metal layer30. A second opening32and a second blind hole33are defined in the second metal layer30. The second opening32penetrates through the second metal layer30, and the second blind hole33does not penetrate through the second metal layer30.

A connecting post40is disposed in the second blind hole33. An end of the connecting post40away from the second metal layer30protrudes from the surface of the second metal layer30. A second receiving groove41is defined in the second metal layer30. The second receiving groove41and the connecting post40are disposed on a same surface of the second metal layer30, and the second receiving groove41does not penetrate the second metal layer30. A second phase change layer23is disposed in the second receiving groove41.

The connecting post40is disposed in the first blind hole13and connected to the solder layer21. The first opening11and the second opening32are connected to each other to form a first through hole43. The first metal layer10and the second metal layer30are connected to each other to form a heat conductive layer44. The first phase change layer20and the second phase change layer23are connected to each other to form a phase change structure24. The phase change structure24is wrapped by the heat conductive layer44. The first through hole43penetrates through the heat dissipation substrate50.

Each insulating layer60is disposed on the heat dissipation substrate50, and also filled in the first through hole43. A groove61is defined in the insulating layer60. A bottom of the groove61corresponds to the heat conductive layer44, causing the heat conductive layer44to partially exposed from the groove61.

Each electronic component71is mounted in the groove61through one bonding sheet70. The bonding sheet70is disposed on the heat conductive layer44, and is in thermal conduction with the heat conductive layer44. In at least one embodiment, the electronic component71may partially protrude from the insulating layer60.

Each base layer81is disposed on the insulating layer60, and the electronic component71is between the base layer81and the insulating layer60. The portion of the electronic component71protruding from the insulating layer60can be embedded in the base layer81.

Each circuit layer93is disposed on the base layer81. A second through hole83is defined in the circuit layer93, the base layer81, and the insulating layer60. A bottom of the second through hole83corresponds to the heat conductive layer44. A heat conductive portion84is disposed in the second through hole83, and is in thermal conduction with the heat conductive layer44.

A slot85is defined in each circuit layer93and the corresponding base layer81. A third through hole86corresponding to the first through hole43is defined in the circuit layer93, the base layer81, and the insulating layer60. A bottom of the slot85corresponds to the electronic component71. A first electric conductive portion91and a second electric conductive portion92are respectively disposed in the slot85and the third through hole86. The first electric conductive portion91can electrically connect the circuit layer93to the adjacent electronic component71. The second electric conductive portion92can electrically connect the two circuit layers93together.

Although the embodiments of the present disclosure have been shown and described, those having ordinary skill in the art can understand that changes may be made within the principles of the present disclosure, up to and including the full extent established by the broad general meaning of the terms used in the claims. It will, therefore, be appreciated that the embodiments described above may be modified within the scope of the claims.