TWI507095B - Wiring board and method of manufacturing the same - Google Patents

Description

Circuit board and its making method

The present invention relates to a circuit board and a method of fabricating the same, and more particularly to a multilayer circuit board and a method of fabricating the same.

In recent years, in order to increase the application of printed circuit boards (PCBs), many technologies have been developed to make printed circuit boards into multi-layer board structures, such as full-layer interconnect high-density link boards (Every Layer Interconnection). , ELIC). The multi-layer board structure is formed by repeatedly stacking and bonding a build-up structure composed of a copper foil and a film (prepreg, pp) onto a core layer for increasing the inside of the printed circuit board. The wiring space is filled with a conductive material in the conductive holes to conduct the layers by an electroplating process. Since the purpose of the multi-layer board structure is to laminate the multi-layer board to increase the wiring space, the connection relationship between the layers is important. In other words, in order to ensure that the lines of each layer can be electrically connected to each other, the alignment method in the manufacturing process is very important.

In the past, most printed circuit boards were X-rays after laminating multiple layers of build-up structures. (X-ray) processing forms vias for alignment on the build-up structure. This practice produces a large offset in a multi-layer board structure with a higher number of layers. Therefore, in order to ensure the yield, the distance between the pads and the sides of the conductive holes must be greater than 70 micrometers (μm). In addition, it is also possible to make a concentric circular positioning pad on the through hole of the core board in advance. This method can avoid the above-mentioned offset caused by X-ray processing, but after subsequent pressing of the multi-layered build-up structure, it is affected by the plate shrinkage and shrinkage, and the positioning pad and the through hole cannot be adjusted as the plate is stretched and contracted. This in turn creates an offset. Therefore, in order to ensure the yield, the distance between the pads and the sides of the conductive holes must be greater than 50 microns. In addition to the above-described alignment method, in a general integrated circuit substrate (IC substrate) process, a laser beam is used to cut both surfaces of the substrate to form a alignment. Through holes, but the above method is not easy to apply in a printed circuit board of a multilayer structure.

The invention provides a method for manufacturing a circuit board, which can improve the alignment accuracy of the circuit board.

The invention provides a circuit board with good alignment accuracy.

The manufacturing method of the wiring board of the present invention includes the following steps. A core layer is provided, wherein a first core line and at least one first positioning ring are formed on a first surface of the core layer. Pressing a first build-up line structure on the first surface and covering the first core line and the first positioning ring, wherein the first build-up line structure comprises a first conductive layer and a first dielectric layer, and a dielectric layer is located on the first conductive layer and the first Between the core lines. A portion of the first build-up line structure corresponding to the first locating ring is removed to expose the first locating ring. Forming a first conductive via on the first build-up line structure by using the first positioning ring as a positioning point, wherein the first conductive via penetrates the first build-up line structure and corresponds to a first connection of the first core line pad.

In an embodiment of the invention, the step of providing the core layer in the above A second core line and at least one second positioning ring are formed on a second surface of the core layer, the second surface is opposite to the first surface, and the second positioning ring corresponds to the first positioning ring.

In an embodiment of the invention, the method for fabricating the above circuit board is further included The following steps are included. After the step of providing the core layer, pressing a second build-up line structure on the second surface and covering the second core line and the second positioning ring, wherein the second build-up line structure comprises a second conductive layer and a The second dielectric layer is between the second conductive layer and the second core line. A portion of the second build-up line structure corresponding to the second locating ring is removed to expose the second locating ring. Forming a second conductive via on the second build-up line structure by using the second positioning ring as the positioning point, wherein the second conductive via penetrates the second build-up line structure and corresponds to a second connection of the second core line pad.

In an embodiment of the invention, the removing corresponds to the first positioning ring. The step of the first first build-up line structure includes skiving a portion of the first build-up line structure by a laser beam, and removing a portion of the second build-up line structure corresponding to the second set ring The step includes cutting a portion of the second build-up line structure by a laser beam.

In an embodiment of the invention, the laser beam comprises carbon dioxide Laser (CO2 laser).

The circuit board of the present invention comprises a core layer, a first core line, and at least a first positioning ring, a first build-up line structure and a first conductive hole. The core layer has a first surface. The first core line is disposed on the first surface. The first positioning ring is disposed on the first surface and located at one side of the first core line. The first build-up line structure is disposed on the first surface. The first build-up line structure covers the first core line and exposes the first positioning ring, wherein the first build-up line structure includes a first conductive layer and a first dielectric layer, and the first dielectric layer is located at the first Between the conductive layer and the first core line. The first conductive via is disposed on the first build-up line structure, wherein the first conductive via extends through the first build-up trace structure and corresponds to a first pad of the first core trace.

In an embodiment of the invention, the circuit board further includes a second core a heart line and at least one second positioning ring. The second core line is disposed on a second surface of the core layer, and the second surface is opposite to the first surface. The second positioning ring is disposed on the second surface and located on one side of the second core line, and the second positioning ring corresponds to the first positioning ring.

In an embodiment of the invention, the circuit board further includes a second increase a layer line structure and a second conductive hole. The second build-up line structure is disposed on the second surface. The second build-up line structure covers the second core line and exposes the second positioning ring, wherein the second build-up line structure includes a second conductive layer and a second dielectric layer, and the second dielectric layer is located at the second Between the conductive layer and the second core line. Second guide The electrical aperture is disposed on the second build-up line structure, wherein the second conductive via extends through the second build-up line structure and corresponds to a second pad of the second core line.

In an embodiment of the invention, the side length of the first pad is larger than the aperture of the first conductive hole, and the distance between one side of the first pad and the corresponding side of the first conductive hole Between 30 micrometers (μm) and 35 micrometers, the side length of the second pad is larger than the aperture of the second conductive hole, and one side of the second pad and the corresponding side of the second conductive hole The distance between 30 microns and 35 microns.

In an embodiment of the invention, the first positioning ring and the second positioning ring respectively have an inner diameter, and the inner diameter has a size greater than 1.5 millimeters (mm).

Based on the above, since the manufacturing method of the circuit board of the present invention forms the first positioning ring on the core layer, and after pressing the first build-up line structure on the first surface, the part of the first build-up line structure is removed. The first positioning ring is exposed to form a first conductive hole on the first build-up line structure by using the first positioning ring as a positioning point. Therefore, the method for fabricating the circuit board of the present invention can repeat the above actions to press more of the first build-up line structure, and form the first build-up line structure by using the same first positioning ring as the anchor point. The first conductive hole prevents the alignment from shifting when processing between different layers. Accordingly, the method for fabricating the circuit board of the present invention can improve the alignment accuracy of the circuit board, so that the circuit board has good alignment accuracy.

The above described features and advantages of the invention will be apparent from the following description.

100‧‧‧ circuit board

110‧‧‧ core layer

120‧‧‧First core line

122‧‧‧First mat

124‧‧‧First cable

130‧‧‧First positioning ring

140‧‧‧second core line

142‧‧‧second mat

150‧‧‧Second positioning ring

160‧‧‧First build-up line structure

162‧‧‧First conductive layer

164‧‧‧First dielectric layer

170‧‧‧Second layered line structure

172‧‧‧Second conductive layer

174‧‧‧Second dielectric layer

180‧‧‧first conductive hole

190‧‧‧Second conductive hole

D1, d2‧‧‧ distance

r‧‧‧Inner diameter

R‧‧‧ outside diameter

S1‧‧‧ first surface

S2‧‧‧ second surface

1A to 1D are schematic cross-sectional views showing a method of fabricating a circuit board according to an embodiment of the present invention.

2 is a schematic diagram of the core layer of FIG. 1.

1A to 1D are schematic cross-sectional views showing a method of fabricating a circuit board according to an embodiment of the present invention. In the present embodiment, the manufacturing method of the circuit board 100 (shown in FIG. 1D) includes the following steps. Hereinafter, a method of fabricating the circuit board 100 will be described with reference to FIG. 1A to FIG.

First, referring to FIG. 1A, in the embodiment, a core layer 110 is provided, wherein the first core line 120 and the at least one first positioning ring 130 are formed on the first surface S1 of the core layer 110. The core layer 110 is, for example, a substrate or a core dielectric layer. The core layer 110 can be pre-processed by a machining process such as drilling or laser. A conductive layer (not shown) is formed on the first surface S1 of the core layer 110 by a plating process, and patterned by a photolithography process to form the first core line 120 and The first positioning ring 130. The first core line 120 includes a first pad 122 and a first connecting line 124. The first pad 122 and the first connecting line 124 are electrically connected to each other. The first positioning ring 130 is located on one side of the first core line 120 and is fabricated in the same process as the first core line 120.

Similarly, please refer to FIG. 1A. In this embodiment, the core is provided in the above. In the step of the core layer 110, the second core line 140 and the second positioning ring 150 are also formed on the second surface S2 of the core layer 110, wherein the second surface S2 is opposite to the first surface S1, and the second positioning ring 150 corresponds to In the first positioning ring 130. Another conductive layer, not shown, is formed on the second surface S2 of the core layer 110 by an electroplating process and patterned by a lithography process to form the second core line 140 and the second positioning ring 150. The second core line 140 includes a second pad 142 and a second connecting line (not shown), and the second pad 142 and the second connecting line are electrically connected to each other. The second positioning ring 150 is located on one side of the second core line 140 and is fabricated in the same process as the second core line 140.

Next, please refer to FIG. 1B. In the embodiment, the core is provided above. After the step of layer 110, the first build-up line structure 160 is pressed onto the first surface S1 and covers the first core line 120 and the first positioning ring 130, wherein the first build-up line structure 160 includes the first conductive layer 162. And a first dielectric layer 164, and the first dielectric layer 164 is located between the first conductive layer 162 and the first core line 120. In the present embodiment, the first conductive layer 162 is, for example, an opaque copper foil, and the material of the first dielectric layer 164 is, for example, a film (prepreg, pp). The first dielectric layer 164 is located between the first conductive layer 162 and the first core line 120 to electrically insulate the first conductive layer 162 from the first core line 120.

Similarly, please refer to FIG. 1B. In this embodiment, the core is provided in the above. After the step of the core layer 110, the second build-up line structure 170 is pressed onto the second surface S2 and covers the second core line 140 and the second positioning ring 150, wherein the second build-up line structure 170 includes the second conductive layer The second dielectric layer 174 is located between the second conductive layer 172 and the second core line 140. In this reality In the embodiment, the second conductive layer 172 is, for example, an opaque copper skin, and the material of the second dielectric layer 174 is, for example, a film. The second dielectric layer 174 is located between the second conductive layer 172 and the second core line 140 to electrically insulate the second conductive layer 172 from the second core line 140. In addition, in this embodiment, the step of pressing the first build-up line structure 160 on the first surface S1 and the step of pressing the second build-up line structure 170 on the second surface S2 can be simultaneously performed by the same process. . However, in other embodiments, the step of pressing the first build-up line structure 160 and the step of pressing the second build-up line structure 170 may also be made separately, or only the first build-up line structure 160 may be fabricated and the press-fit omitted. The second build-up line structure 170, the present invention is not limited by the above.

Next, referring to FIG. 1C, in the embodiment, the first pressing in the above After the step of the build-up line structure 160 on the first surface S1, a portion of the first build-up line structure 160 corresponding to the first locating ring 130 is removed to expose the first locating ring 130. Specifically, since the first conductive layer 162 of the first build-up line structure 160 covering the first positioning ring 130 is an opaque copper skin, the first positioning ring 130 serving as an anchor point in the subsequent process cannot be An add-on line structure 160 is externally identified or read. Therefore, in the present embodiment, after the first build-up line structure 160 is pressed, a portion of the first build-up line structure 160 corresponding to the first positioning ring 130 is removed, for example, by a laser beam. A portion of the first build-up line structure 160 is skiving to expose the first locating ring 130. In this embodiment, the laser beam is, for example, a CO2 laser, and the parameters of the laser beam may be according to actual needs (for example, the copper skin as the first conductive layer 162 and the first dielectric layer). 164 film thickness) adjustment.

In addition, in this embodiment, the pair is removed by the CO2 laser cutting process. The step of the portion of the first build-up line structure 160 of the first positioning ring 130 includes removing a portion of the first build-up layer corresponding to the first positioning ring 130 by using a positioning hole (not shown) as a positioning point. Line structure 160. The positioning hole is located on the core layer 110, for example, a through hole penetrating through the core layer 110 formed by X-ray processing in the pre-processing process of the core layer 110, and the positioning hole is not the first build-up line. The structure 160 is covered, for example, at a corner of the core layer 110, etc., where the layout of the line is not affected. Accordingly, the laser beam can be accurately aligned by the positioning holes to a portion of the first build-up line structure 160 corresponding to the first positioning ring 130.

Similarly, please refer to FIG. 1C. In this embodiment, in the above-mentioned pressing After the second build-up line structure 170 is on the second surface S2, a portion of the second build-up line structure 170 corresponding to the second positioning ring 150 is removed to expose the second positioning ring 150. The step of removing a portion of the second build-up line structure 170 corresponding to the second positioning ring 150 is, for example, cutting a portion of the second build-up line structure 170 by a laser beam, wherein the laser beam is, for example, a carbon dioxide laser, and The step of removing a portion of the second build-up line structure 170 corresponding to the second positioning ring 150 includes removing a portion of the second build-up line structure corresponding to the second positioning ring 150 by using the positioning hole as the positioning point. 170. Accordingly, since the first positioning ring 130 and the second positioning ring 150 can be respectively exposed by the CO2 laser cutting process, and the first positioning ring 130 and the second positioning ring 150 correspond to each other, the embodiment can be mutually The first positioning ring 130 and the second positioning ring 150 corresponding to each other but not in contact with each other replace the conventional through-hole positioning holes, and the first positioning ring 130 and the second positioning ring 150 are used as positioning points in the subsequent process, so that Example The completed circuit board 100 (shown in Figure 1D) has good precision.

Next, referring to FIG. 1D, in the embodiment, after the step of removing a portion of the first build-up line structure 160 corresponding to the first positioning ring 130, the first positioning ring 130 is used as the positioning point. A first conductive via 180 is formed on the first build-up trace structure 160, wherein the first conductive via 180 extends through the first build-up trace structure 160 and corresponds to the first pad 122 of the first core trace 120. Since the first positioning ring 130 is exposed through the laser cutting process in the previous step, it can be read by a reading device (for example, a charge coupled device (CCD)) as a positioning point. In addition, the step of forming the first conductive via 180 on the first build-up line structure 160 is, for example, cutting a portion of the first build-up line structure 160 corresponding to the first pad 122 by a laser beam, and exposing the first Pad 122.

Similarly, please refer to FIG. 1D. In this embodiment, the above pair is removed. After the step of the portion of the second build-up line structure 170 of the second positioning ring 150, the second conductive hole 190 is formed on the second build-up line structure 170 by using the second positioning ring 150 as a positioning point, wherein The two conductive holes 190 extend through the second build-up line structure 170 and correspond to the second pads 142 of the second core line 140. The second positioning ring 150 can also be read by the reading device as a positioning point, and the step of forming the second conductive hole 190 on the second build-up line structure 170 is, for example, by laser beam cutting corresponding to the second connection. A portion of the second build-up line structure 170 of the pad 142 exposes the second pad 142. So far, the circuit board 100 of the present embodiment is initially completed.

In addition, in the embodiment, the first conductive via 180 is formed in the above manner. After the step on the first build-up line structure 160, the electroplating process can again be performed An unillustrated conductive layer is formed on the first build-up wiring structure 160, and the conductive layer is filled in the first conductive via 180. Then, the conductive layer is patterned by the lithography process by using the first positioning ring 130 as a positioning point to form a first circuit layer and another first positioning ring (not shown), wherein the first circuit layer The first core line 120 is connected through the first conductive hole 180, and the first positioning ring corresponds to the aforementioned first positioning ring 130 on the first surface S1. Thereafter, the step of pressing the build-up line structure and removing the build-up line structure corresponding to the positioning ring to expose the positioning ring may be repeated, and the conductive ring is formed on the build-up line structure by using the positioning ring as a positioning point. And exposing the pads of the circuit layer, and then forming a conductive layer by an electroplating process, and connecting the conductive layer to the pads of the circuit layer through the conductive holes.

Similarly, the second conductive via 190 is formed on the second build-up line in the above manner. After the step on the structure 170, an unillustrated conductive layer may be formed on the second build-up wiring structure 170 by an electroplating process, and the conductive layer is filled in the second conductive via 190. Then, the conductive layer is patterned by the lithography process by using the second positioning ring 150 as a positioning point to form a second circuit layer and another second positioning ring (not shown), wherein the second circuit layer The second core line 140 is connected through the second conductive hole 190, and the second positioning ring corresponds to the aforementioned second positioning ring 150 on the second surface S2. Thereafter, the step of pressing the build-up line structure and removing the build-up line structure corresponding to the positioning ring to expose the positioning ring may be repeated, and the conductive ring is formed on the build-up line structure by using the positioning ring as a positioning point. And exposing the pads of the circuit layer, and then forming a conductive layer by an electroplating process, and connecting the conductive layer to the pads of the circuit layer through the conductive holes.

It can be seen that for the first surface S1 and the second surface S2 of the core layer 110 The process performed (for example, forming the first conductive via 180 and the second conductive via 190, plating the conductive layer in a subsequent process and patterning the conductive layer by a lithography process, or continuing to press more of the build-up wiring structure and The first positioning ring 130 and the second positioning ring 150 are respectively corresponding to each other, and the first surface S1 and the first surface of the core layer 110 can be positioned. The two surfaces S2 are read separately. Accordingly, by the design of positioning the first positioning ring 130 and the second positioning ring 150 respectively, the manufacturing method of the circuit board 100 of the present embodiment can press the multi-layered layered wiring structure and the first positioning ring The positioning of the second positioning ring 150 is not limited by the thickness of the circuit board 100, thereby reducing the misalignment of the positioning holes formed by X-ray processing and causing the subsequent conductive holes or pads to be offset. situation.

Referring to FIG. 1D , in the embodiment, the circuit board 100 formed by the above manufacturing method includes a core layer 110 , a first core line 120 , a first positioning ring 130 , a second core line 140 , and a second positioning ring 150 . a first build-up line structure 160, a second build-up line structure 170, a first conductive via 180, and a second conductive via 190. The core layer 110 has a first surface S1 and a second surface S2, and the second surface S2 is opposite to the first surface S1. The first core line 120 is disposed on the first surface S1 and includes a first pad 122 and a first connecting line 124. The first positioning ring 130 is disposed on the first surface S1 and located at one side of the first core line 120. In contrast, the second core line 140 is disposed on the second surface S2 of the core layer 110 and includes a second pad 142 and a second connecting line (not shown). The second positioning ring 150 is disposed on the second surface S2. And located on one side of the second core line 140, and the second positioning ring 150 corresponds to the first positioning ring 130.

In this embodiment, the first build-up line structure 160 is disposed on the first surface S1, and the second build-up line structure 170 is disposed on the second surface S2. The first build-up line structure 160 covers the first core line 120 and exposes the first positioning ring 130, wherein the first build-up line structure 160 includes a first conductive layer 162 and a first dielectric layer 164, and the first dielectric Layer 164 is between first conductive layer 162 and first core line 120. The first conductive layer 162 is, for example, a copper foil, and the first dielectric layer 164 is, for example, a film. For related content, reference may be made to the foregoing, and no further details are provided herein. The first conductive vias 180 are disposed on the first build-up line structure 160 , wherein the first conductive vias 180 extend through the first build-up trace structure 160 and correspond to the first pads 122 of the first core traces 120 . In contrast, the second build-up line structure 170 covers the second core line 140 and exposes the second positioning ring 150, wherein the second build-up line structure 170 includes the second conductive layer 172 and the second dielectric layer 174, and The second dielectric layer 174 is located between the second conductive layer 172 and the second core line 140. The second conductive via 190 is disposed on the second build-up line structure 170 , wherein the second conductive via 190 extends through the second build-up trace structure 170 and corresponds to the second pad 142 of the second core trace 140 .

2 is a schematic diagram of the core layer of FIG. 1. Referring to FIG. 1D and FIG. 2, in the embodiment, the number of the first positioning rings 130 located on the first surface S1 of the core layer 110 is four, respectively located at four corners of the first surface S1, wherein FIG. 2 is only a schematic diagram for explaining the above configuration relationship, and the ratio of the core layer 110 to the first positioning ring 130 is not representative of the actual ratio. In this embodiment, the first setting The bit ring 130 has an inner diameter r and an outer diameter R, wherein the inner diameter r has a size greater than 1.5 mm and the outer diameter R has a size of 6 mm. Accordingly, when the circuit board 100 forms a wiring layer by the electroplating process after the first conductive via 180 is formed, the conductive material used in the electroplating process can be prevented from being filled into the first positioning ring 130 to affect the subsequent alignment. Precision. Similarly, although FIG. 2 only shows the first surface S1 of the core layer 110 and the first positioning ring 130, since the second positioning ring 150 located on the second surface S2 corresponds to the first positioning ring 130, the same also has the above. The features of the first positioning ring 130. In other embodiments, the circuit board 100 can adjust the positions and numbers of the first positioning ring 130 and the second positioning ring 150 according to actual needs, and the invention is not limited thereto.

Because the first positioning ring 130 and the second positioning ring 150 are used in this embodiment. The row positioning design has a good alignment accuracy, so in the embodiment, the first pad 122 and the second pad 142 of the first conductive via 180 and the second conductive via 190 have a single-sided size (this The requirement that the one-sided dimension is defined as the distance between the side of the first pad 122 or the second pad 142 relative to the corresponding side of the first conductive via 180 or the second conductive via 190 is small. Specifically, in the embodiment, the side length of the first pad 122 is larger than the aperture of the first conductive hole 180, and one side of the first pad 122 and the corresponding side of the first conductive hole 180 The distance d1 (shown in Figure 1D) is between 30 microns and 35 microns. Similarly, the side length of the second pad 142 is greater than the aperture of the second conductive hole 190, and the distance d2 between the side of the second pad 142 and the corresponding side of the second conductive hole 190 is between 30. Micron to between 35 microns. In other words, since the manufacturing method of the circuit board 100 of the present embodiment has good precision and the offset of the alignment is small, even if a pad having a small size is disposed, the pair will not be generated. The bit is offset to make the conductive hole and the pad unconnectable.

In summary, since the circuit board of the present invention is fabricated on the core layer Forming a first positioning ring, and after pressing the first build-up line structure on the first surface, removing a portion of the first build-up line structure to expose the first positioning ring to be used as the first positioning ring The first conductive hole is formed on the first build-up line structure by positioning the point. Therefore, the method for fabricating the circuit board of the present invention can repeat the above actions to press more of the first build-up line structure, and form the first on each of the first build-up line structures by using the first positioning ring as an anchor point. Conductive holes to avoid misalignment when machining between different layers. Similarly, a second positioning ring corresponding to the first positioning ring may be formed on the other surface of the core layer, and the positioning function is provided by the second positioning ring, so that the circuit board of the present invention can be in the core layer. The two surfaces each have an anchor point to press more of the build-up line structure. In addition, the positioning ring of the present invention can be fabricated simultaneously with the core circuit without adding additional processes. Accordingly, the method for fabricating the circuit board of the present invention can improve the alignment accuracy of the circuit board, so that the circuit board has good alignment accuracy.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧ circuit board

110‧‧‧ core layer

120‧‧‧First core line

122‧‧‧First mat

124‧‧‧First cable

130‧‧‧First positioning ring

140‧‧‧second core line

142‧‧‧second mat

150‧‧‧Second positioning ring

160‧‧‧First build-up line structure

162‧‧‧First conductive layer

164‧‧‧First dielectric layer

170‧‧‧Second layered line structure

172‧‧‧Second conductive layer

174‧‧‧Second dielectric layer

180‧‧‧first conductive hole

190‧‧‧Second conductive hole

D1, d2‧‧‧ distance

S1‧‧‧ first surface

S2‧‧‧ second surface

Claims (11)

A method for manufacturing a circuit board, comprising: providing a core layer, wherein a first core line and at least one first positioning ring are formed on a first surface of the core layer; and a first build-up line structure is pressed a first core line and the first positioning ring, wherein the first build-up line structure comprises a first conductive layer and a first dielectric layer, and the first dielectric layer is located at the first Between a conductive layer and the first core line; removing a portion of the first build-up line structure corresponding to the first positioning ring to expose the first positioning ring; and positioning the first positioning ring Forming a first conductive via on the first build-up line structure, wherein the first conductive via extends through the first build-up line structure and corresponds to a first pad of the first core line; The first positioning ring serves as a positioning point to form a third positioning ring on the first build-up line structure; and presses a third build-up line structure on the first build-up line structure, and the removal corresponds to the Part of the third positioning loop Structure to expose the third retaining ring, and by the third positioning ring as anchor points to form a hole in a third conductive layer on the third gain circuit structure. The method for fabricating a circuit board according to claim 1, wherein in the step of providing the core layer, a second surface of the core layer is formed with a second surface a core line and at least one second positioning ring, the second surface is opposite to the first surface, and the second positioning ring corresponds to the first positioning ring. The method of manufacturing the circuit board of claim 2, wherein after the step of providing the core layer, the method further comprises: pressing a second build-up line structure on the second surface, and covering the second a core line and the second positioning ring, wherein the second build-up line structure comprises a second conductive layer and a second dielectric layer, and the second dielectric layer is located at the second conductive layer and the second core line Removing a portion of the second build-up line structure corresponding to the second positioning ring to expose the second positioning ring; and forming a second conductive hole by using the second positioning ring as a positioning point In the second build-up line structure, the second conductive via extends through the second build-up line structure and corresponds to a second pad of the second core line. The method of fabricating a circuit board according to claim 3, wherein the step of removing a portion of the first build-up line structure corresponding to the first positioning ring comprises: skiving a portion by a laser beam And the step of removing the portion of the second build-up line structure corresponding to the second positioning ring comprises cutting a portion of the second build-up line structure by a laser beam. The method of fabricating a circuit board according to claim 4, wherein the laser beam comprises a CO2 laser. A circuit board comprising: a core layer having a first surface; a first core line disposed on the first surface; at least one first positioning ring disposed on the first surface and located on one side of the first core line; a first build-up line structure disposed on the first surface, the first build-up line structure covering the first core line, and exposing the first positioning ring, wherein the first build-up line structure includes a first a conductive layer and a first dielectric layer, the first dielectric layer is located between the first conductive layer and the first core line; a first conductive hole, by using the first positioning ring as a positioning point Disposed on the first build-up line structure, wherein the first conductive hole penetrates the first build-up line structure and corresponds to a first pad of the first core line; at least one third positioning ring, by The first positioning ring is disposed as the positioning point on the first build-up line structure; a third build-up line structure is disposed on the first build-up line structure, and the third positioning ring is exposed; and a third conductive hole by the third positioning ring Positioning point is disposed on the third layer wiring structure increases. The circuit board of claim 6, further comprising: a second core line disposed on a second surface of the core layer, wherein the second surface is opposite to the first surface; and at least one a positioning ring disposed on the second surface and located in the second core One side of the cardiac line, and the second positioning ring corresponds to the first positioning ring. The circuit board of claim 7, further comprising: a second build-up line structure disposed on the second surface, the second build-up line structure covering the second core line, and exposing the a second positioning ring, wherein the second build-up line structure comprises a second conductive layer and a second dielectric layer, and the second dielectric layer is located between the second conductive layer and the second core line; A second conductive via is disposed on the second build-up line structure, wherein the second conductive via extends through the second build-up trace structure and corresponds to a second pad of the second core trace. The circuit board of claim 8, wherein a side length of the first pad is larger than an aperture of the first conductive hole, and a side of the first pad corresponds to the first conductive hole. The distance between one side is between 30 micrometers (μm) and 35 micrometers, the side length of the second pad is larger than the aperture of the second conductive hole, and one side of the second pad is The distance between the corresponding one side of the second conductive via is between 30 micrometers and 35 micrometers. The circuit board of claim 7, wherein the first positioning ring and the second positioning ring respectively have an inner diameter, and the inner diameters have a size greater than 1.5 millimeters (mm). A circuit board comprising: a core layer having a first surface and a second surface; a first core line disposed on the first surface; At least one first positioning ring disposed on the first surface and located on one side of the first core line; a first build-up line structure disposed on the first surface, the first build-up line structure covering The first core line, and exposing the first positioning ring, wherein the first build-up line structure comprises a first conductive layer and a first dielectric layer, and the first dielectric layer is located at the first conductive layer Between the first core line and the first conductive line, the first conductive ring is disposed on the first build-up line structure by using the first positioning ring as an anchor point, wherein the first conductive hole runs through the first build-up line a first pad of the first core line; a second core line disposed on the second surface; and at least one second positioning ring disposed on the second surface and located at the second core One side of the second core line, and the first positioning ring and the second positioning ring do not contact each other.