CN101290890A - Circuit board with embedded conductive circuit and manufacturing method thereof - Google Patents

Abstract

The invention provides a method for manufacturing a circuit board with embedded conductive circuits, which forms an embedded conductive circuit layer on the surface of a substrate and increases the height of pads and fingers to facilitate the subsequent glue filling process.

Description

Circuit board with embedded conductive circuit and manufacturing method thereof

technical field

The present invention relates to a circuit board and its manufacturing method, more particularly to a circuit board with embedded conductive lines and its manufacturing method.

Background technique

In recent years, as electronic components have become multifunctional and smaller, the technology of packaging substrates has also developed rapidly in order to achieve light, thin, short, small and highly dense circuit patterns. In particular, such light, thin, short, small and highly dense circuit patterns are required to be used in chip scale package (CSP) product groups. In order to form dense circuit patterns on a small-sized substrate, embedded conductive circuits are generally formed on the substrate by pressing.

Referring to FIG. 1a to FIG. 1h, the existing manufacturing method for forming embedded conductive circuits on a substrate is to form a copper layer 120 on a carrier board 110, and the copper layer 120 has protruding structures 122 and 124 on it. The patterns of the protruding structures 122, 124 correspond to the patterns of the conductive lines to be formed on the substrate (see FIGS. 1a and 1b). Then, the carrier 110 is pressed with a soft substrate, such as a B stage (B stage) BT (Bismaleimide Triazine) substrate 130 , so that the protrusion structures 122 and 124 on the copper layer 120 are embedded in a surface 132 of the substrate 130 . The other surface 134 of the substrate 130 can also be press-bonded with another copper layer 140 having a protruding structure 142 as required (see FIG. 1 c ). Then the carrier 110 is removed from the copper layers 120, 140, and the copper layers 120, 140 are thinned by etching, so that the surfaces 132, 134 of the substrate 130 are exposed, which were originally on the copper layers 120, 140. The protruding structures 122 , 124 , 142 remain on the surfaces 132 , 134 of the substrate 130 and are flush with the surfaces 132 , 134 of the substrate. These protruding structures 122 , 124 , 142 buried on the surfaces 132 , 134 of the substrate 130 will eventually form the conductive circuit layer on the substrate 130 (see FIG. 1 d ).

Next, a through hole 150 is formed on the substrate 130 by etching or drilling, and a copper layer 160 is formed on the surfaces 132, 134 of the substrate 130 and the inner wall of the through hole 150 by electroless plating (see FIG. 1 e ). . Then form a layer of dry film 170 on the substrate surfaces 132, 134 as a shielding layer for electroplating, so that the conductive circuit layers on the substrate surfaces 132, 134, that is, the structures 122, 124 buried on the substrate surfaces 132, 134 , 142 are covered by a dry film 170, while the through hole 150 is exposed, and then a layer of copper 180 is electroplated on the inner wall of the through hole 150 (see FIG. 1f). The dry film 170 and the copper layer 160 formed on the substrate surfaces 132 , 134 by electroless plating are then removed. A solder resist layer 190 is then formed on the substrate surfaces 132, 134 to expose the structures 122, 124, 142, and a layer of organic solderability preservative (OSP) is formed on the structures 122, 142 (see FIG. 1g). A dry film 170 is then formed on the structures 122 and 142, and a layer of Ni/Au 195 is electroplated on the structure 124 (see FIG. 1h). Finally, the dry film 170 is removed.

The structure 124 plated with the nickel/gold layer 195 is used as a finger for electrically connecting with an external circuit through a bonding wire, and the structures 122 and 142 are used as a pad for connecting with an external circuit through a soldering wire. The ball is electrically connected with the external circuit. Since the structures 124 used as fingers need to be electroplated, all the structures 124 are electrically connected together to facilitate the electroplating. However, since the structures 124 are electrically connected to each other, they cannot be electrically tested when they leave the factory.

In addition, since the formed pads 122 are flush with the surface 132 of the substrate 130 and the solder resist layer 190 generally has a considerable thickness, when the chip is electrically connected to the pads 122 by solder balls, the solder balls will Only part of the height exposes the solder resist layer 190 (not shown), which will make the gap (Die Gap) between the chip and the substrate 130 too small, so that the underfill or molding compound (Molding compound) ) is not easy to fill the gap between the chip and the substrate 130, thus causing voids.

In view of this, it is necessary to propose a method for manufacturing a circuit board with embedded conductive circuits to solve the above problems.

Contents of the invention

The object of the present invention is to provide a method of manufacturing a circuit board with embedded conductive traces, wherein the height of the pads is increased.

In order to achieve the above purpose, the manufacturing method of the circuit board with embedded conductive circuit according to the first embodiment of the present invention is to form a copper layer on a carrier board first, and the second surface of the copper layer is attached to the carrier board , and the first surface opposite to the second surface has protruding structures, and the patterns of these protruding structures correspond to the patterns of the conductive lines to be formed on the substrate. Then, the carrier board is pressed against the B-stage BT substrate, so that the protruding structure on the copper layer is embedded in a surface of the substrate. The other surface of the substrate can also be laminated with another copper layer having a protrusion structure as required. Then the carrier board is removed from the copper layer, so that the second surface of the copper layer is exposed, and a layer of dry film is formed on the copper layer as a shielding layer for electroplating. The first and second regions on the second surface of the layer are exposed.

Then, the substrate is electroplated, so that a nickel/gold layer is electroplated on the exposed first and second regions. Afterwards, the dry film is removed, and the copper layer is etched to expose the surface of the substrate. At this time, the protrusion structure on the copper layer remains on the surface of the substrate and is flush with the surface of the substrate. During the etching process, since the nickel/gold layer serves as a masking layer to protect the underlying copper layer from being etched away, a structure protruding from the substrate is formed. Finally, an electroplating through hole is formed on the substrate, and a solder resist layer is formed on the surface of the substrate, and the nickel/gold layer is exposed.

The manufacturing method of the circuit board with embedded conductive circuit of the second embodiment of the present invention is substantially the same as the manufacturing method of the circuit board with embedded conductive circuit of the first embodiment, the difference lies in the copper layer The first and second areas on the second surface do not need to be plated with nickel/gold as a masking layer, but a dry film is formed only on the first and second areas, and the copper layer is etched so that The surface of the substrate is exposed, while the protrusion structure on the copper layer remains on the surface of the substrate and is flush with the surface of the substrate. In the etching process, the dry film is used as a masking layer to protect the underlying copper layer from being etched away, so as to form a structure protruding from the substrate. Afterwards, the dry film is removed, and an electroplated through hole is formed on the substrate, and a solder mask layer is formed on the surface of the substrate, and the first and second regions are exposed and a layer of organic solder flux is applied.

Another object of the present invention is to provide a circuit board manufactured by the above method.

According to the method for manufacturing a circuit board with embedded conductive circuits of the present invention, the protruding structure buried on the surface of the substrate forms the conductive circuits on the substrate, and the copper layers in the first and second regions are respectively used to As pads and fingers, it is used to electrically connect with external circuits, such as a chip. Since the first area used as a pad protrudes from the substrate, when the chip is electrically connected to the first area by using solder balls, more of the height of the solder balls will expose the solder resist layer, thereby increasing the distance between the chip and the substrate. The gap makes it easier for the primer or mold sealer to fill the gap between the chip and the substrate during packaging to avoid the generation of holes. In addition, because the second area used as the finger does not need to be electrically connected together, it can be electrically tested before leaving the factory.

In order to make the above and other objects, features, and advantages of the present invention more apparent, the embodiments of the present invention, together with the attached figures, are described in detail below.

Description of drawings

FIG. 1a to FIG. 1h are conventional manufacturing methods of circuit boards with embedded conductive circuits.

2a to 2g are the manufacturing method of the circuit board with embedded conductive circuit according to the first embodiment of the present invention.

3a to 3b are the manufacturing method of the circuit board with embedded conductive lines according to the second embodiment of the present invention.

Detailed ways

2a to 2g, the manufacturing method of the circuit board with embedded conductive lines according to the first embodiment of the present invention is to form a metal layer 220 on a carrier board 210, such as a copper layer, the copper layer 220 The second surface 223 is attached to the carrier board 210, and the first surface 221 opposite to the second surface 223 has protruding structures 222 and 224. The patterns of the formed conductive lines correspond (see Fig. 2a and Fig. 2b). Then, the carrier 210 is pressed against a soft substrate, such as a B stage (B stage) BT (BismaleimideTriazine) substrate 230 , so that the protrusion structures 222 and 224 on the copper layer 220 are embedded in a surface 232 of the substrate 230 . The other surface 234 of the substrate 230 can also be laminated with another metal layer 240 having a protruding structure 242 , such as a copper layer, as required (see FIG. 2 c ). Then the carrier 210 is removed from the copper layers 220, 240, so that the copper layer 240 and the second surface 223 of the copper layer 220 are exposed, and a dry layer is formed on the copper layer 240 and the second surface 223 of the copper layer 220. The film 270 is used as a masking layer for electroplating, and an opening 272 is opened on the dry film 270 to expose the region 226 on the second surface 223 of the copper layer 220 and the region 246 on the copper layer 240 (see FIG. 2 d ).

Next, electroplating is performed on the substrate 230, so that a metal layer 280, such as a nickel/gold layer, is electroplated on the exposed regions 226 and 246 (see FIG. 2e). Afterwards, the dry film 270 is removed, and the copper layers 220, 240 are etched, so that the surfaces 232, 234 of the substrate 230 are exposed, and at this time, the original protrusion structures 222, 224, 242 on the copper layers 220, 240 remain. on the surfaces 232 , 234 of the substrate 230 and flush with the surfaces 232 , 234 of the substrate. During the etching process, since the Ni/Au layer 280 acts as a shielding layer, it can protect the underlying copper layer 220 from being etched away, so as to form a structure protruding from the substrate 230 (see FIG. 2f ). Finally, a plated through hole 250 is formed on the substrate 230, and a solder resist layer 290 is formed on the substrate surfaces 232, 234, and the nickel/gold layer 280 is exposed (see FIG. 2g).

Referring to Fig. 3a to Fig. 3b, the manufacturing method of the circuit board with embedded conductive circuit of the second embodiment of the present invention is substantially the same as the manufacturing method of the circuit board with embedded conductive circuit of the first embodiment, so The difference is that the area 226 on the second surface 223 of the copper layer 220 and the area 246 on the copper layer 240 do not need to be plated with the nickel/gold layer 280 as a shielding layer, but the dry film 270 is only formed on the area 226 and 246, and etch the copper layers 220, 240, so that the surfaces 232, 234 of the substrate 230 are exposed, and the protruding structures 222, 224, 242 originally on the copper layers 220, 240 remain on the surface of the substrate 230 232, 234, and flush with the substrate surfaces 232, 234. During the etching process, the dry film 270 serves as a shielding layer to protect the underlying copper layer 220 from being etched away, so as to form a structure protruding from the substrate 230 (see FIG. 3 a ). Afterwards, the dry film 270 is removed, and a plated through hole 250 is formed on the substrate 230, and then a solder resist layer 290 is formed on the substrate surfaces 232, 234, and the regions 226, 246 are exposed and a layer of organic protection is applied. flux (see Figure 3b).

Referring to FIG. 2g, the circuit board of the present invention includes a substrate 230 having two opposite surfaces 232, 234 and a through hole 250 plated with copper. The conductive circuit layer 222 is embedded in the substrate 230 and exposed on the surface 232, and the conductive circuit layer 242 is embedded in the substrate 230 and exposed on the surface 234, wherein the conductive circuit layer 222 has a region 226 protruding from the substrate 230. The surface 232 of the substrate 230 , and the conductive circuit layer 242 has a region 246 protruding from the surface 234 of the substrate 230 . The nickel/gold layer 280 is formed on the region 226 to be used as a pad or a finger for electrically connecting with an external circuit through solder balls or bonding wires, and the nickel/gold layer 280 is also formed on the region 246 to Used for electrical connection with another circuit board.

According to the manufacturing method of the circuit board with embedded conductive lines of the present invention, the protruding structures 222, 224, 242 buried on the surfaces 232, 234 of the substrate 230 form the conductive lines on the substrate 230, and the copper in the region 226 The layer 220 and the copper layer 240 located in the area 246 are used to electrically connect with the external circuit, wherein the area 226 on the structure 222 is used as a pad for electrically connecting with, for example, a chip through solder balls, and the area on the structure 224 The area 226 is used as a finger for electrically connecting with, for example, a chip by bonding wires, and the area 246 on the structure 242 is used as a pad for electrically connecting with, for example, another circuit board (not shown) via solder balls. . Since the area 226 used as a pad protrudes from the substrate 230, when the chip is electrically connected to the area 226 by using solder balls, more parts of the solder ball height will expose the solder resist layer 290 (not shown), thereby increasing the contact between the chip and the area 226. The gap between the substrates 230 makes it easier for the primer to fill the gap between the chip and the substrate 230 during packaging, so as to avoid the generation of holes. In addition, because the area 226 on the structure 224 used as a finger does not need to be electrically connected together, it can be electrically tested before leaving the factory.

Although the present invention has been disclosed by the aforementioned preferred embodiments, it is not intended to limit the present invention. Any skilled person can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims (11)

1. A method for manufacturing a circuit board, comprising the steps of: providing a substrate having two opposite first and second surfaces; A first metal layer is formed on the first surface of the substrate, the first metal layer has two opposite first surfaces and second surfaces, and a protruding structure is formed on the first surface of the first metal layer, which is buried the first surface of the substrate, wherein the first metal layer has a first region on the second surface; forming a shielding layer on the first region; etching the first metal layer, so that the first metal layer exposed outside the masking layer is removed; remove the masking layer; and A solder resist layer is formed on the first surface of the substrate, and the first metal layer is exposed. 2. The method of claim 1, wherein the step of forming a first metal layer on the first surface of the substrate comprises: Provide the carrier board; forming the first metal layer on the carrier, wherein the second surface of the first metal layer is attached to the carrier; pressing the carrier plate to the substrate, so that the protruding structure of the first metal layer is embedded in the first surface of the substrate; and Remove the carrier board. 3. A method of manufacturing a circuit board, comprising the steps of: providing a substrate having two opposite first and second surfaces; A first metal layer is formed on the first surface of the substrate, the first metal layer has two opposite first surfaces and second surfaces, and a protruding structure is formed on the first surface, which is embedded in the first surface of the substrate , wherein the second surface of the first metal layer has a first region and a second region; forming a shielding layer on the second surface of the first metal layer, and exposing the first and second regions; forming a second metal layer on the first and second regions; remove the masking layer; etching the first metal layer such that the first metal layer exposed outside the second metal layer is removed; and A solder resist layer is formed on the first surface of the substrate, and the second metal layer is exposed. 4. The method of claim 3, wherein the step of forming a first metal layer on the first surface of the substrate comprises: Provide the carrier board; forming the first metal layer on the carrier, wherein the second surface of the first metal layer is attached to the carrier; pressing the carrier plate to the substrate, so that the protruding structure of the first metal layer is embedded in the first surface of the substrate; and Remove the carrier board. 5. The method of claim 3, further comprising: A third metal layer is formed on the second surface of the substrate, the third metal layer has two opposite first surfaces and second surfaces, a protruding structure is formed on the first surface of the third metal layer, which is embedded the second surface of the substrate, wherein the third metal layer has a first region on the second surface; forming the shielding layer on the second surface of the third metal layer, and exposing the first region of the third metal layer; forming a fourth metal layer on the first region of the third metal layer; removing the masking layer on the second surface of the third metal layer; etching the third metal layer so that the third metal layer exposed outside the fourth metal layer is removed; and The solder resist layer is formed on the second surface of the substrate, and the fourth metal layer is exposed. 6. A circuit board comprising: a substrate having two opposite first and second surfaces; The first conductive circuit layer is embedded in the substrate and exposed on the first surface of the substrate, wherein the first conductive circuit layer has a first region and a second region, and the first and second regions protrude from the first surface of the substrate. the first surface of the substrate; and The solder resist layer is formed on the first surface of the substrate and exposes the first and second regions. 7. The circuit board of claim 6, further comprising: The metal layer is formed on the first and second regions of the first conductive circuit layer. 8. The circuit board as claimed in claim 7, wherein the metal layer on the first region is used as a pad for electrically connecting with external circuits through solder balls. 9. The circuit board as claimed in claim 7, wherein the metal layer on the second region is used as a finger for electrically connecting with an external circuit through a bonding wire. 10. The circuit board of claim 6, further comprising: a second conductive circuit layer embedded in the substrate and exposed on the second surface of the substrate, wherein the second conductive circuit layer has a third region protruding from the second surface of the substrate, Wherein the solder resist layer is further formed on the second surface of the substrate and exposes the third region. 11. The circuit board as claimed in claim 7, wherein the metal layer is a nickel/gold layer.

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