Method for manufacturing a circuit board

A circuit board includes a circuit substrate, a solder, and a surrounding portion. The circuit substrate includes a connecting pad. The solder is formed on a surface of the connecting pad. The surrounding portion is formed on the surface of the connecting pad and cooperates with the connecting pad to form a groove receiving the solder. The surrounding portion surrounds the solder and is spaced from the solder. A method for manufacturing a circuit board is also provided.

FIELD

The subject matter herein generally relates to a circuit technology, especially relates to a circuit board and a method of manufacturing the circuit board.

BACKGROUND

With the development of the electronic products, sizes of the electronic products are becoming smaller. Correspondingly, an important element in the electronic products, the circuit board needs to be smaller. So that connecting pads and wiring spacings of the circuit board also need to become smaller, which makes coating of solder paste with precisions become more difficult.

Therefore, there is room for improvement within the art.

DETAILED DESCRIPTION

FIG.1illustrates a flowchart of a method in accordance with an embodiment. The embodiment method for manufacturing a circuit board is provided by way of embodiments, as there are a variety of ways to carry out the method. Each block shown inFIG.1represents one or more processes, methods, or subroutines carried out in the method. Furthermore, the illustrated order of blocks can be changed. Additional blocks may be added or fewer blocks may be utilized, without departing from this disclosure. The embodiment method can begin at block21.

At block21, referring toFIG.2, a composite substrate10is provided. The composite substrate10includes a carrier11and a removable film13stacked along a first direction X.

The carrier11may be made of a material selected from a group consisting of metal, hard resin, glass, and any combination thereof. For example, the carrier11may be a metal plate or a glass plate.

At block22, referring toFIG.3, a resin layer15is pressed on a side of the removable film13facing away from the carrier11, and a first opening161is formed to pass through the resin layer15and the removable film13along the first direction X. A portion of the carrier11is exposed from the first opening161.

At block23, referring toFIG.4, a solder20fills in the first opening161.

Preferably, the soler20may fully fill in the first opening161, and a surface of the soler20facing away from the carrier11may be flush with a surface of the resin layer15facing away from the carrier11.

The solder20may be, but is not limited to, solder paste or copper paster.

At block24, referring toFIG.5, a second opening163penetrating the resin layer15along the first direction X is formed around the solder20, and the second opening163is spaced from the solder20. A surrounding portion17around the solder20is formed in the second opening163by plating metal. The surrounding portion17is spaced from the solder20.

Preferably, the second opening163may be formed with a center of the solder20as a center point to surround the solder20.

At block25, referring toFIGS.6and7, a circuit substrate30is formed on the surface of the resin layer15facing away from the carrier11. The circuit substrate30includes a first wiring layer31combined with the surface of the resin layer15facing away from the carrier11. The first wiring layer31includes a connecting pad313corresponding the surrounding portion17and the solder20. The connecting pad313seals a side of the surrounding portion17to cooperate with the surrounding portion17to form a groove301. The solder20is received in the groove301.

The first wiring layer31may further include at least one signal line311spaced from the connecting pad313.

The circuit substrate30may be a single-layer circuit board, a double-layer circuit board, or a multi-layer circuit board. In at least one embodiment, referring to FIG.7, the circuit substrate30is a double-layer circuit board. Specifically, the circuit substrate30may further include a dielectric film33and a second wiring layer35stacked and spaced along the first direction X. The second wiring layer35is electrically connected to the first wiring layer31, and the dielectric film33is interposed between the first wiring layer31and the second wiring layer35.

At block26, referring toFIG.8, the composite substrate10is removed, and a first portion of the resin layer15received in the groove301is removed.

In at least one embodiment, a height of the solder20is greater than a depth of the groove301, thereby facilitating an electrical connection between the solder20and external electronic components (not shown).

The first portion of the resin layer15received in the groove301may be removed by, but not limited to, laser ablation followed by plasma removal of scum.

At block27, referring toFIG.9, a second portion of the resin layer15outside the groove301is removed, thereby obtaining a circuit board100.

In at least one embodiment, the block27may be omitted. The second portion of the resin layer15may be used as a protective layer of the circuit board100a(shown inFIG.8) to protect the first wiring layer31, and there is no need to add a solder mask.

In at least one embodiment, before the block25, the method may further include roughening the surface of the soler20facing away from the carrier11, so as to increase an adhesive property between a connecting pad313subsequently formed and the solder20.

FIG.10illustrates a flowchart of an embodiment of a method for manufacturing the circuit substrate30. The method can begin at block251.

At block251, referring toFIG.11, a first dielectric layer331is pressed on the surface of the surface of the resin layer15facing away from the carrier11and is patterned. The patterned first dielectric layer331includes a third opening332corresponding to the surrounding portion17and the solder20. The surrounding portion17and the solder20are exposed from the third opening332.

The patterned first dielectric layer331may further include at least one wiring opening334spaced from the third opening332.

At block252, referring toFIG.6, a first wiring layer31corresponding the patterned first dielectric layer331is formed to be embedded in the first dielectric layer331. The first wiring layer31includes a connecting pad313embedded in the third opening332.

The first wiring layer31may include at least one signal line311embedded in the at least one wiring opening334.

At block253, referring toFIG.7, a second dielectric layer335is pressed on a side of the first wiring layer31facing away from the carrier11and a side of the first dielectric layer331facing away from the carrier11, and a second wiring layer35is formed on a side of the second dielectric layer335facing away from the carrier11. The second wiring layer35is electrically connected to the first wiring layer31. The first dielectric layer331and the second dielectric layer335form a dielectric film33.

In at least one embodiment, the second wiring layer35may electrically connected to the connecting pad313through a conductive via36.

In at least one embodiment, a depth of the first opening161may be less than or equal to a depth of the second opening163. The formation of the solder20and the formation of the surrounding portion17are not limited to the above-mentioned method. In the illustrated embodiment, it is preferable that the depth of the first opening161is greater than the depth of the second opening163.

FIG.9illustrates an embodiment of a circuit board100. The circuit board100includes a circuit substrate30, a surrounding portion17, and a solder20. The circuit substrate30includes a first wiring layer31including a connecting pad313. The solder20and the surrounding portion17are formed on the connecting pad313. The surrounding portion17cooperates with the connecting pad313to form a groove301to receive the solder20. The surrounding portion17surrounds the solder20and is spaced from the solder20.

In at least one embodiment, a height of the solder20may preferably be greater than a depth of the groove301, thereby facilitating an electrical connection between the solder20and external electronic components (not shown). In at least one embodiment, the height of the solder20may be less than or equal to the depth of the groove301.

A surface of the solder20facing the connecting pad313may be roughened, which is beneficial to increase an adhesive property between a connecting pad313subsequently formed and the solder20.

In at least one embodiment, referring toFIG.8, the circuit board100amay further include a resin layer18formed a side of the circuit substrate30where the solder20is provided, and covering an area of the first wiring layer31except the connecting pad313.

A surface of the resin layer18facing away from the first wiring layer31may be flush with a surface of the surrounding portion17facing away from the first wiring layer31.

The circuit substrate30may be a single-layer circuit board, a double-layer circuit board, or a multi-layer circuit board. In at least one embodiment, the circuit substrate30is a double-layer circuit board. Specifically, the circuit substrate30may further include a dielectric film33and a second wiring layer35. The first wiring layer31is embedded in the dielectric film33from a first side of the dielectric film33. The second wiring layer35is formed on a second side of the dielectric film33facing away from the first wiring layer31, and is electrically connected to the first wiring layer31.

In at least one embodiment, the second wiring layer35may electrically connected to the connecting pad313through a conductive via36.

In the above method of for manufacturing a circuit board and the above circuit board, the solder20may be accurately arranged in the groove301, which is beneficial to improve a stability of the connection between the solder20and the connecting pad313. At the same time, the solder20is spaced from the surrounding portion17, which provide a sufficient space for the solder20when the solder20is melted, thereby reducing a rish of the solder20overflowing and contacting other wirings.