TW202423192A - Circuit board with embedded component and method of fabricating the same - Google Patents

Abstract

A circuit board with embedded components and a method of fabricating the same are provided. The circuit board with the embedded components includes a first conducting layer, a first inner plate disposed on the first conducting layer, a first circuit layer disposed on the first inner plate, at least two ceramic substrates embedded within the first inner plate and disposed between the first conducting layer and the first circuit layer, a second inner plate disposed on the first circuit layer, at least two electric components embedded within the second inner plate and respectively disposed over the ceramic substrate, a second circuit layer disposed over the second inner plate, a third inner plate disposed on the second circuit layer, a second conducting layer disposed on the third inner plate and through vias extending from the second conducting layer to the first conducting layer. The electronic component is disposed over the ceramic substrate to decrease thermal resistance and increase thermal conduction.

Description

Embedded component circuit board and manufacturing method thereof

The present invention relates to a circuit board and a manufacturing method thereof, and in particular to an embedded component circuit board and a manufacturing method thereof.

In recent years, electronic equipment has developed rapidly, with multifunctionality, high circuit density and miniaturization being the main research directions. Among them, embedding various electronic components into printed circuit boards (PCBs) is a common technical means. However, embedding electronic components into printed circuit boards usually has the problem of component heat dissipation, especially in the application of power semiconductors and automotive chips.

One aspect of the present invention is to provide a circuit board with embedded components, which includes a ceramic substrate embedded in the circuit board and an electronic component disposed on the ceramic substrate to enhance heat dissipation effect.

Another aspect of the present invention is to provide a method for manufacturing a circuit board with embedded components, which includes arranging electronic components on a ceramic substrate to obtain a circuit board with good heat dissipation effect.

According to one aspect of the present invention, a circuit board with embedded components is provided, which includes a first conductive layer, a first inner board disposed on the first conductive layer, a first circuit layer disposed on the first inner board, at least two ceramic substrates embedded in the first inner board and between the first conductive layer and the first circuit layer, a second inner board disposed on the first circuit layer, at least two electronic components embedded in the second inner board and disposed on the ceramic substrates, a second circuit layer disposed on the second inner board, a third inner board disposed on the second circuit layer, a second conductive layer disposed on the third inner board, and a plurality of through-hole structures extending from the second conductive layer to the first conductive layer. The electronic components are electrically connected to each other through the first circuit layer, the through-hole structures, and the second circuit layer.

According to an embodiment of the present invention, the embedded component circuit board further includes a plurality of third circuit layers disposed between the third inner board and the second conductive layer; and a plurality of fourth inner boards disposed between the third circuit layer and the second conductive layer.

According to one embodiment of the present invention, the embedded component circuit board further includes a cured resin disposed between the at least two ceramic substrates and the first inner plate.

According to an embodiment of the present invention, the embedded component circuit board further includes a plurality of conductive blind vias connecting the at least two electronic components and the second circuit layer.

According to one embodiment of the present invention, the at least two electronic components include a first transistor and a second transistor, and the drain of the first transistor is electrically connected to the source of the second transistor.

According to another aspect of the present invention, a method for manufacturing a circuit board with embedded components is provided. The method includes providing a composite layer, wherein the composite layer includes a first conductive layer, a first inner plate, and an initial metal layer, and the first inner plate is between the first conductive layer and the initial metal layer; forming at least two openings in the composite layer; disposing at least two ceramic substrates in the openings respectively; after disposing the ceramic substrates in the openings, patterning the initial metal layer to form a first circuit layer; disposing at least two electronic components on the ceramic substrates respectively; disposing a second inner plate on the first circuit layer and the electronic components; forming a second circuit layer on the second inner plate; disposing a third inner plate on the second circuit layer; disposing a second conductive layer on the third inner plate; and forming a plurality of through-hole structures extending from the second conductive layer to the first conductive layer. The at least two electronic components are electrically connected to each other through the first circuit layer, the through-hole structure and the second circuit layer.

According to one embodiment of the present invention, there are a plurality of pores between the at least one ceramic substrate and the composite layer, and before arranging the at least two electronic components, the method further comprises filling the pores with a curing resin.

According to one embodiment of the present invention, before setting the third inner board, the method further includes forming a plurality of conductive blind vias between the at least two electronic components and the second circuit layer.

According to one embodiment of the present invention, the step of forming the through-hole structure includes forming a plurality of openings extending from the top of the second conductive layer to the first conductive layer; depositing metal material on the side walls of the openings; and after depositing the metal material on the side walls of the openings, filling the openings with resin.

According to an embodiment of the present invention, before disposing the ceramic substrate, the method further comprises disposing an adhesive layer under the first conductive layer to fix the at least one ceramic substrate in the first inner plate.

By applying the embedded component circuit board and the manufacturing method thereof, the electronic components are arranged on the ceramic substrate and embedded in the inner board, and the electronic components are electrically connected by via holes to achieve the effect of reducing thermal resistance and improving heat conduction.

The present invention provides many different embodiments or examples to implement different features of the invention. The specific examples of components and configurations described below are intended to simplify the present invention. These are of course only examples and are not intended to be limiting. For example, a description of a first feature formed on or above a second feature includes embodiments in which the first feature and the second feature are in direct contact, and also includes embodiments in which other features are formed between the first feature and the second feature, so that the first feature and the second feature are not in direct contact. In addition, the present invention repeats component symbols and/or letters in various specific examples. The purpose of this repetition is to simplify and clarify the description and does not indicate a relationship between the various discussed embodiments and/or configurations.

Furthermore, spatially relative terms, such as "beneath," "below," "lower," "above," "upper," etc., are used to facilitate description of the relationship of a part or feature to other parts or features depicted in the drawings. Spatially relative terms include different orientations of the component when in use or operation in addition to the orientation depicted in the drawings. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used in the present invention can be interpreted in this manner.

As used in the present invention, "around", "about", "approximately" or "substantially" generally means within 20%, within 10%, or within 5% of the stated value or range.

The electronic components in the known embedded component circuit board are heat-dissipated by filling blind holes, but the density and thickness of the blind holes are limited in manufacturing, so there is a problem of insufficient heat conduction. Another known method is to use copper blocks for heat dissipation, but because the copper blocks are conductive, thermal interface materials (TIM) must be set at the bottom of the copper blocks for insulation, but the disadvantage is that it will cause an increase in thermal resistance. Therefore, the present invention provides an embedded component circuit board and a manufacturing method thereof, in which electronic components are set on a ceramic substrate and the electronic components are electrically connected using conductive holes to achieve the effect of reducing thermal resistance and improving thermal conductivity.

Please refer to FIG. 1, which shows a cross-sectional view of an embedded component circuit board 100 according to some embodiments of the present invention. The embedded component circuit board 100 includes a first conductive layer 102, a first inner board 104, and a first circuit layer 106, and the first inner board 104 is between the first conductive layer 102 and the first circuit layer 106. In some embodiments, the first inner board 104 includes a material with a low coefficient of thermal expansion (CTE), such as an X-Y axis thermal expansion coefficient of about 9 ppm/°C to 10 ppm/°C, or a material with a lower thermal expansion coefficient, but the present invention is not limited thereto.

The embedded component circuit board 100 further includes a ceramic substrate 150 embedded in the first inner plate 104. FIG. 1 only shows two ceramic substrates 150, but the present invention is not limited thereto, that is, the number of ceramic substrates 150 may be two or more. In some embodiments, a curing resin 152 is filled between the ceramic substrate 150 and the first inner plate 104 to fill the gap between the ceramic substrate 150 and the first inner plate 104. Since the ceramic substrate 150 has good thermal conductivity, it helps to quickly conduct the heat energy generated during the operation of the embedded component circuit board 100, and can avoid overheating due to long-term operation and causing product failure. Furthermore, the ceramic substrate 150 also has an insulating property, so the main heat conduction path and the conductive path of the electronic component 160 can be separated to achieve the effect of thermoelectric separation.

The embedded component circuit board 100 further includes a second inner board 112 disposed on the first circuit layer 106 and an electronic component 160 embedded in the second inner board 112, wherein the electronic component 160 is disposed above the ceramic substrate 150. FIG. 1 only shows two electronic components 160, but the present invention is not limited thereto, that is, the number of the electronic components 160 may be two or more. In some embodiments, a conductive glue layer 155 is disposed between the electronic component 160 and the first circuit layer 106. In some embodiments, the electronic component 160 may be a transistor, such as a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). In some embodiments where the electronic component 160 is a field effect transistor, the embedded device circuit board 100 may include at least two electronic components 160 both being field effect transistors, wherein the drain of one transistor (ie, one of the electronic components 160) is electrically connected to the source of another transistor (ie, another electronic component 160).

In some embodiments, since the thermal expansion coefficient of the ceramic substrate 150 and the electronic component 160 is generally about 3 ppm/°C to 5 ppm/°C, and the ceramic substrate 150 and the electronic component 160 are respectively embedded in the first inner plate 104 and the second inner plate 112, the first inner plate 104 and the second inner plate 112 may include a material with a low thermal expansion coefficient, for example, less than 9 ppm/°C, but the present invention is not limited to this.

The embedded component circuit board 100 further includes a second circuit layer 120 disposed on the second inner board 112 and a third inner board 130A on the second circuit layer 120. In some embodiments, as shown in FIG1 , the embedded component circuit board 100 may selectively include a plurality of third circuit layers (e.g., a third circuit layer 122 and a third circuit layer 124) and a plurality of fourth inner boards (e.g., a fourth inner board 130B and a fourth inner board 130C). In some embodiments, the third inner board 130A, the fourth inner board 130B, and the fourth inner board 130C all include a low thermal expansion coefficient material similar to the first inner board 104. In some embodiments, the conductive blind via 170 is disposed between the electronic component 160 and the second circuit layer 120 to electrically connect the plurality of electronic components 160 via the second circuit layer 120 and the through-hole structure 180.

The embedded component circuit board 100 further includes a second conductive layer 140 on the top fourth inner board 130C. In some embodiments, a through-hole structure 180 is provided to extend from the second conductive layer 140 to the first conductive layer 102. In some embodiments, the through-hole structure 180 includes a metal (such as copper) coated on the sidewall and a resin or ink filled inside.

2A to 2G illustrate cross-sectional views of intermediate stages of the manufacturing process of the embedded component circuit board 100 according to some embodiments of the present invention. First, referring to FIG. 2A , a composite layer 110 is provided, wherein the composite layer 110 includes a first conductive layer 102, a first inner plate 104, and an initial metal layer 106′. The first inner plate 104 is on the first conductive layer 102, and the initial metal layer 106′ is on the first inner plate 104. The first inner plate 104 includes a material with a low thermal expansion coefficient, for example, an X-Y axis thermal expansion coefficient of about 9 ppm/°C to 10 ppm/°C.

Referring to FIG. 2B , at least two openings O1 are formed in the composite layer 110, wherein the embodiment of FIG. 2B is illustrated by taking two openings O1 as an example. Next, an adhesive layer 210 may be disposed at the bottom of the composite layer 110 to fix a ceramic substrate to be placed thereon. In some embodiments, the adhesive layer 210 is a polyethylene terephthalate (PET) adhesive layer.

Referring to FIG. 2C , two ceramic substrates 150 are disposed in the openings O1 (refer to FIG. 2B ) of the composite layer 110 . It should be noted that the number of ceramic substrates 150 may be more than two, so the number of openings O1 should be adjusted according to the number of ceramic substrates 150 . In some embodiments, the ceramic substrate 150 is a double-sided copper-plated ceramic substrate, that is, the bottom and top of the ceramic substrate 150 respectively include a copper layer 150A. In some embodiments, the ceramic substrate 150 is a direct plated copper (DPC) ceramic substrate. In some embodiments, since the width W of the opening O1 (see FIG. 2B ) is greater than the width of the ceramic substrate 150 (for example, the difference between the width W of the opening O1 (see FIG. 2B ) and the width of the ceramic substrate 150 is about 150 μm to about 250 μm), a gap 201 is provided between the ceramic substrate 150 and the composite layer 110 .

Referring to FIG. 2D , the resin is filled into the pores 201 (refer to FIG. 2C ), and the baking conditions are controlled to form the cured resin 152, so that the pores 201 between the composite layer 110 and the ceramic substrate 150 are filled with the cured resin 152. Then, after the cured resin 152 is filled, the adhesive layer 210 at the bottom of the composite layer 110 can be removed (refer to FIG. 2C ).

Please refer to FIG. 2E. Then, the initial metal layer 106' in FIG. 2D is patterned to form the first circuit layer 106, wherein patterning the initial metal layer 106' may include not only lithography and etching but also electroplating. In addition, the first circuit layer 106 may also be formed by a semi-additive method, wherein in the process of forming the first circuit layer 106, grinding may be used to thin the initial metal layer 106' and the copper layer 150A and remove a portion of the solidified resin 152, so that the initial metal layer 106' and the copper layer 150A can be bonded to each other to form the first circuit layer 106.

Afterwards, the electronic component 160 is disposed on the first circuit layer 106 and directly above the ceramic substrate 150. In some embodiments, before the electronic component 160 is disposed, a conductive glue layer 155 may be disposed on the first circuit layer 106 and above the ceramic substrate 150. In some specific examples, the conductive glue layer 155 is a sintered silver paste. In some embodiments, the electronic component 160 includes a plurality of electrodes, such as an electrode 162, an electrode 164, and an electrode 166. If the electronic component 160 is a field effect transistor, the electrode 162, the electrode 164, and the electrode 166 may be a drain, a source, and a gate, respectively.

Referring to FIG. 2F , the second inner plate 112 is disposed on the first circuit layer 106 and the electronic element 160, and the second circuit layer 120 is formed on the second inner plate 112. It should be understood that the second inner plate 112 must first be formed with a groove to accommodate the electronic element 160. In detail, the second inner plate 112 can be formed by stacking multiple dielectric layers, wherein at least one dielectric layer has one or more openings for accommodating the electronic element 160, and another dielectric layer covers the electronic element 160 so that the electronic element 160 can be embedded in the second inner plate 112. In addition, the above-mentioned dielectric layer is, for example, a prepreg.

Next, a conductive blind via 170 is formed in the second inner board 112 to connect the electronic element 160 and the second circuit layer 120, and the two electronic elements 160 can be electrically connected to each other using the conductive blind via 170 and the second circuit layer 120. In some embodiments, the formation of the conductive blind via 170 may include the following steps: forming an opening in the second inner board 112 (for example, using a suitable method such as laser), the opening extending from the second circuit layer 120 to the top of the electronic element 160; then, filling the aforementioned opening with a conductive material, for example, using a suitable method such as electroplating.

Referring to FIG. 2G , a third inner board 130A is formed on the second circuit layer 120, and then, a plurality of third circuit layers 122, a fourth inner board 130B, a third circuit layer 124, and a fourth inner board 130C are selectively formed in sequence on the third inner board 130A. Then, a second conductive layer 140 is formed on the third inner board 130A or the top fourth inner board (e.g., the fourth inner board 130C). It should be understood that the number of the third circuit layer and the fourth inner board shown in FIG. 2G is only for illustration, and the present invention is not limited thereto.

Please refer to FIG. 1 again. In the structure of FIG. 2G , a through-hole structure 180 is formed extending from the second conductive layer 140 to the first conductive layer 102. In this way, the embedded component circuit board 100 can be manufactured. The formation of the through-hole structure 180 may include the following steps. First, a plurality of openings are formed extending from the top of the second conductive layer 140 through a plurality of inner plates (i.e., the third inner plate 130A, the fourth inner plate 130B, and the fourth inner plate 130C), a plurality of circuit layers (i.e., the second circuit layer 120, the third circuit layer 122, and the third circuit layer 124), the second inner plate 112, the first circuit layer 106, and the first inner plate 104 to the first conductive layer 102. Next, metal material is deposited on the sidewalls of the openings, for example, by chemical plating or electroplating. Then, resin is filled into the openings to fill the gaps between the metal materials.

In some embodiments where the electronic component 160 is a transistor (e.g., MOSFET), the drain (e.g., electrode 162) of one electronic component 160 can be electrically connected to the source (e.g., electrode 164) of another electronic component 160 using the conductive blind via 170 and the through-hole structure 180. Therefore, the heat conduction path of the electronic component 160 mainly passes through the ceramic substrate below it, while the electrical conduction path mainly passes through the conductive blind via 170 above it, so that the effect of thermal and electrical separation can be achieved.

As described above, the present invention provides an embedded component circuit board and a manufacturing method thereof, wherein electronic components are disposed on a ceramic substrate and embedded in an inner plate having a low thermal expansion coefficient, and the electronic components are electrically connected using conductive blind vias and through-hole structures to achieve the effects of reducing thermal resistance, improving thermal conductivity and thermoelectric separation.

Although the present invention has been disclosed as above with several embodiments, they are not intended to limit the present invention. Anyone with ordinary knowledge in the technical field to which the present invention belongs can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be defined by the scope of the attached patent application.

100: Embedded component circuit board 102: First conductive layer 104: First inner board 106: First circuit layer 106': Initial metal layer 110: Composite layer 112: Second inner board 120: Second circuit layer 122,124: Third circuit layer 130A: Third inner board 130B,130C: Fourth inner board 140: Second conductive layer 150: Ceramic substrate 150A: Copper layer 152: Cured resin 155: Conductive adhesive layer 160: Electronic component 162: Electrode 164: Electrode 166: Electrode 170: Conductive blind via 180: Through hole structure 201: Pore 210: Adhesive layer O1: Opening W: Width

The present invention is best understood by reading the following detailed description in conjunction with the accompanying drawings. It should be noted that, as is standard practice in the industry, many features are not drawn to scale. In fact, for the sake of clarity of discussion, the dimensions of many features may be arbitrarily scaled. [FIG. 1] illustrates a cross-sectional view of an embedded component circuit board according to some embodiments of the present invention. [FIG. 2A] to [FIG. 2G] illustrate cross-sectional views of intermediate stages of the manufacturing process of an embedded component circuit board according to some embodiments of the present invention.

Domestic storage information (please note in the order of storage institution, date, and number) None Foreign storage information (please note in the order of storage country, institution, date, and number) None

100: Embedded component circuit board

102: First conductive layer

104: First inner plate

106: First circuit layer

112: Second inner plate

120: Second circuit layer

122,124: Third circuit layer

130A: Third inner plate

130B, 130C: Fourth inner plate

140: Second conductive layer

150: Ceramic substrate

152: Curing resin

155: Conductive adhesive layer

160: Electronic components

162:Electrode

164:Electrode

170: Conductive blind vias

180: Through-hole structure

Claims (10)

A circuit board with embedded components, comprising: a first conductive layer; a first inner board, disposed on the first conductive layer; a first circuit layer, disposed on the first inner board; at least two ceramic substrates, embedded in the first inner board and between the first conductive layer and the first circuit layer; a second inner board, disposed on the first circuit layer; at least two electronic components, embedded in the second inner board and disposed on the ceramic substrates respectively; a second circuit layer, disposed on the second inner board; a third inner board, disposed on the at least one second circuit layer; a second conductive layer, disposed on the at least one third inner board; and A plurality of through-hole structures extend from the second conductive layer to the first conductive layer, wherein the at least two electronic components are electrically connected to each other through the first circuit layer, the through-hole structures and the second circuit layer. The embedded component circuit board as described in claim 1 further comprises: A plurality of third circuit layers, disposed between the third inner board and the second conductive layer; and A plurality of fourth inner boards, disposed between the third circuit layer and the second conductive layer. The embedded component circuit board as described in claim 1 further comprises: A cured resin disposed between the at least two ceramic substrates and the first inner plate. The embedded component circuit board as described in claim 1 further comprises: A plurality of conductive blind vias connecting the at least two electronic components and the second circuit layer. An embedded component circuit board as described in claim 1, wherein the at least two electronic components include a first transistor and a second transistor, and the drain of the first transistor is electrically connected to the source of the second transistor. A method for manufacturing a circuit board with embedded components, comprising: Providing a composite layer, wherein the composite layer comprises a first conductive layer, a first inner plate and an initial metal layer, and the first inner plate is between the first conductive layer and the initial metal layer; Forming at least two openings in the composite layer; Disposing at least two ceramic substrates in the openings respectively; After disposing the ceramic substrates in the openings, patterning the initial metal layer to form a first circuit layer; Disposing at least two electronic components on the ceramic substrates respectively; Disposing a second inner plate on the first circuit layer and the at least two electronic components; Forming a second circuit layer on the second inner plate; Disposing a third inner plate on the second circuit layer; Disposing a second conductive layer on the third inner plate; and A plurality of through-hole structures are formed extending from the second conductive layer to the first conductive layer, wherein the at least two electronic components are electrically connected to each other through the first circuit layer, the through-hole structure and the second circuit layer. The manufacturing method of the embedded component circuit board as described in claim 6, wherein there are multiple pores between the at least one ceramic substrate and the composite layer, and before setting the at least two electronic components, it further includes: Filling the curing resin in the pores. The manufacturing method of the embedded component circuit board as described in claim 6, wherein before setting the third inner board, it further includes: Forming a plurality of conductive blind holes between the at least two electronic components and the second circuit layer. The manufacturing method of the embedded component circuit board as described in claim 6, wherein the step of forming the through-hole structure includes: forming a plurality of openings extending from the top of the second conductive layer to the first conductive layer; depositing a metal material on the side walls of the openings; and after depositing the metal material on the side walls of the openings, filling the openings with resin. The manufacturing method of the embedded component circuit board as described in claim 6, wherein before the ceramic substrate is provided, it further comprises: Providing an adhesive layer under the first conductive layer to fix the at least one ceramic substrate in the first inner plate.