Manufacturing method of connector

The instant disclosure relates to a manufacturing method of connector which comprises the following steps. The first step is to provide a substrate layer and forming a first metal layer on the substrate layer. The next step is to pattern the first metal layer to form a wiring layer. The next step is to form a dielectric layer on the wiring layer, wherein the dielectric layer is formed with at least one via hole to partially expose the wiring layer and a conductive structure arranged on the inner wall of the at least one via hole and electrically connected to the wiring layer. The next step is to form a first protective layer on the dielectric layer and at least one cantilever structure between the first protective layer and the dielectric layer. The last step is to remove the substrate layer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The instant disclosure relates to a manufacturing method of connector; in particular, to a manufacturing method of connector with a relatively thin thickness.

2. Description of Related Art

The connector can be used as an electrical bridge for electrically connecting different electronic elements. Nowadays, various connectors are required for use in the 3C electronic devices, e.g., cell phones, notebooks, etc. For the trend of miniaturization of the 3C electronic devices, further miniaturization of the connector has been requested.

A conventional method for manufacturing the connector comprises providing a core layer formed with conductive vias and a circuit, and subsequently pressing a dielectric layer with at least one cantilever onto the core layer, wherein the at least one cantilever is connected to the circuit through the conductive vias. However, the conventional method must be subjected to via holes electroplating process to form the core layer with the conductive vias, thus resulting in a complex process. Besides, the connector cannot meet the miniaturization requirements due to its thickness.

SUMMARY OF THE INVENTION

The object of the instant disclosure is to provide a manufacturing method for a connector with a relatively thin thickness.

In order to achieve the aforementioned objects, according to an embodiment of the instant disclosure, a manufacturing method of connector comprises: providing a substrate layer and forming a first metal layer on the substrate layer; patterning the first metal layer to form a wiring layer; forming a dielectric layer on the wiring layer, wherein the dielectric layer is formed with at least one via hole to partially expose the wiring layer and a conductive structure arranged on the inner wall of the at least one via hole and electrically connected to the wiring layer; forming a first protective layer on the dielectric layer and at least one cantilever structure between the first protective layer and the dielectric layer, wherein the at least one cantilever structure is electrically connected to the wiring layer via the conductive structure; and removing the substrate layer.

Base on the above, at least one electrically conductive via coupled between the cantilever structure to the wiring layer can be formed without the use of a via hole plating method, whereby the overall process can be simplified in comparison with the conventional manufacturing method. Besides, the connector manufactured by the aforementioned method does not have any core layers, whereby the thickness of the connector can be reduced to meet the requirement of miniaturization.

In order to further appreciate the characteristics and technical contents of the instant disclosure, references are hereunder made to the detailed descriptions and appended drawings in connection with the instant disclosure. However, the appended drawings are merely shown for exemplary purposes, rather than being used to restrict the scope of the instant disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer toFIGS. 1A-1G, which are cross-sectional views schematically showing a process for manufacturing a connector according to a first embodiment of the present invention.

The first step, as shown inFIG. 1A, is to provide a substrate layer110and two first metal layers120. For the instant embodiment, the substrate layer110includes a core layer112, two second metal layers114, and two release films116. The second metal layers114are arranged on two opposite surfaces of the core layer112. The release films116are arranged on the second metal layers114respectively, and configure to temporarily combine the substrate layer110to the first metal layer120. Each of the first metal layers120has a thickness in a range between 15 μm and 25 μm, and each of the second metal layers114has a thickness in a range between 2 μm and 5 μm.

In general, the substrate layer110is disposed to act as a carrier of the subsequently formed electrical elements and circuits. That is, the substrate layer110can be a sheet laminate material (i.e., copper foil substrate) for use in manufacturing printed circuit boards. The core layer112can be made of a prepreg which is formed by impregnating a fibrous material such as carbon fiber or glass fiber with an epoxy resin. For example, the core layer112can be, made of a cyanate ester (CE) prepreg, a polyimide (PI) prepreg, or a bismaleimide (BMI) prepreg. The second metal layer114can be made of an aluminum-based material, a copper-based material, or a copper alloy. For example, the second metal layer114can be made of brass, phosphor bronze, berylliun alloy, or coalesced copper. The release film116is capable of easily peeling off from the second metal layer114, such that the substrate layer110can easily be removed. However, the substrate materials are not restricted thereto.

The next step, as shown inFIG. 1B, is to pattern the first metal layer120to form a wiring layer120′. For the instant embodiment, the thickness of the first metal layer120is reduced by etching and mechanically polishing, and then a photolithography process and an etching process are conducted to selectively deposit a metal on the surface of the first metal layer120. Specifically, a patterned photoresist layer is formed on the first metal layer120, and the metal is sequentially formed on the uncovered portion of the first metal layer120to form the wiring layer120′. In various embodiments, a subtractive method can be performed on the first metal layer120to form the wiring layer120′. That is, the uncovered portion of the first metal layer120can be removed by etching

The next step, as shown inFIG. 1C, is to form a dielectric layer130on the wiring layer120′, wherein the dielectric layer130is formed with at least one via hole H1to partially expose the wiring layer120′. Specifically, the at least one via hole H1can be formed in the dielectric layer130before or after pressing the dielectric layer130onto the wiring layer120′, wherein a portion of the dielectric layer130can be removed by laser drilling. However, the present invention is not limited to the timing of the formation of the at least one via hole H1.

For the instant embodiment, the dielectric layer130can be made of the dielectric material exhibiting viscosity and low flowability such as a low/no flow prepreg. The dielectric layer130can be formed on the wiring layer120′ by printing or applying. The at least one via hole H1can be formed in the dielectric layer130by mechanically drilling or laser trimming.

The next step, as shown inFIG. 1D, is to form a conductive structure M1arranged on the inner wall of the at least one via hole H1and electrically connected to the wiring layer120′. Firstly, a photoresist or a dry film (not shown) is formed on the dielectric layer130, wherein not only the outer surface of the dielectric layer130but also a portion of the inner wall of the at least one via hole H1are covered by said photoresist or dry film. Next, a copper plating layer or a conductive paste such as a metal paste (i.e., copper paste or silver paste) or a conductive polymer is formed on the uncovered portion of the at least one via hole H1to form the conductive structure M1. That is, at least part of the inner wall of the at least one via hole H1are covered by the conductive structure M1.

However, in various embodiments, the at least one via hole H1and the conductive structure M1can be formed in the dielectric layer130after pressing the dielectric layer130onto the wiring layer120′.

The next step, as shown inFIG. 1E, is to form a first protective layer150aon the dielectric layer130and at least one cantilever structure140between the first protective layer150aand the dielectric layer130, wherein the at least one cantilever structure140is electrically connected to the wiring layer120′ via the conductive structure M1. Specifically, the cantilever structure140is positioned substantially in correspondence with the via hole H1of the dielectric layer130. The cantilever structure140has a fixing portion142and a free end portion144. The fixing portion142is arranged in a peripheral region near the at least one via hole H1and connected to the wiring layer120′. The free end portion144extended from the fixing portion142is protrudes out of the dielectric layer130via the via hole H1.

It is worth to note that, the amount of the cantilever structure140and the layout thereof are adjustable according to the product requirements. The at least one cantilever structure140can be arranged at two opposite sides of the substrate layer110respectively (shown inFIG. 1E) or at one side of the substrate layer110.

For the instant embodiment, the cantilever structure140can be made of a metal foil (not shown) and formed by a photolithography process and an etching process. In various embodiments, the cantilever structure140can be formed by a mechanical machining process such as a punching process, whereby the free end portion144is bent relative the fixing portion142. Besides, the cantilever structure140can be formed by the aforementioned photolithography, etching, and mechanical machining processes.

To further explain the details, the method of forming the cantilever structure140comprises at least following steps. A photolithography process and an etching process are conducted to remove a portion of a metal foil (not shown) to define a planar pattern for formation of the cantilever structure140. Next, a punching process is conducted to the patterned metal foil to form the cantilever structure140, wherein the free end portion144is bent relative the fixing portion142. Last, the metal foil with the cantilever structure140is formed on the dielectric layer130by pressing or adhering. However, in various embodiments, the cantilever structure140can be formed after pressing the metal layer onto the dielectric layer130.

It is worth to note that, the remaining metal portions connected with the cantilever structure140can be patterned to form a circuit in the aforementioned patterning process. However, the present invention is not restricted thereto; said remaining metal portions connected with the cantilever structure140can be completely removed.

The next step is to form a first protective layer150aon the cantilever structure140, wherein the first protective layer150ais formed with at least one via hole H2, and the cantilever structure140further protrudes out of the first protective layer150avia the via hole H2. It is worth to note that, the cantilever structure140and the first protective layer150acan be pressed onto the dielectric layer130in the same or different process.

The next step, as shown inFIGS. 1E and 1F, is to substantially form at least two semi-finished connectors100′ at two opposite sides of the substrate layer110. Specifically, the two opposite sides of the substrate layer110each can be combined with the one of the wiring layers120′ via the corresponding release film116. Thus, at least two semi-finished connectors100′ can be produced at one time by peeling off the release film116from the second metal layer114.

The next step, as shown inFIGS. 1G, is to selectively remove the wiring layer120′ to form a wiring layer121with a predetermined wiring pattern. A portion of the wiring layer120′ can be removed by etching or polishing to partially expose the substantially covered surface of the dielectric layer130. The connector100can be obtained after the completion of the aforementioned steps. In various embodiments, a subtractive method can be performed on the first metal layer120to form the wiring layer121without etching or polishing the wiring layer120′.

Referring toFIG. 1Gagain. After formation of the wiring layer121, a second protective layer150bcan be formed on the wiring layer120′ and opposite to the dielectric layer130. The second protective layer150bis formed with at least one through hole C1to partially expose the wiring layer120′. For the instant embodiment, the second protective layer150bcan be a layer of dry film/wet film solder mask, and the through hole C1can be solder mask defined (SMD) or non-solder mask defined (NSMD). A soldering material such as solder ball or solder pillar can be filled into the through hole C1of the second protective layer150b. Said soldering material can be replaced by the nickel-gold layer or organic solderability preservatives (OSP).

Base on the above, the two opposite sides of the substrate layer110each can be combined with the one of the wiring layers120′ via the corresponding release film116. Thus, at least two semi-finished connectors100′ can be produced at one time by peeling off the release film116from the second metal layer114.

As a result, at least one electrically conductive via coupled between the cantilever structure to the wiring layer can be formed without the use of a via hole plating method, whereby the overall process can be simplified in comparison with the conventional manufacturing method. Besides, the connector manufactured by the aforementioned method does not have any core layers, whereby the thickness of the connector can be reduced to meet the requirement of miniaturization