TWI433622B - Fabrication methods for circuit substrate structure with smooth surface - Google Patents

Description

Method for manufacturing circuit substrate structure with smooth surface

The present invention relates to a method of fabricating a circuit substrate structure, and more particularly to a circuit substrate structure having a smooth surface and a method of fabricating the same.

In the advanced electronic assembly technology, the printed circuit board and the module can effectively increase the unit density of the wafer on the substrate, shorten the length of the connected wafer conductor, reduce the capacitance effect between the networks, and improve the performance and reliability of the line. In the prior art, printed circuit boards are mostly made of composite laminates, which are first plated with a layer of copper foil and then etched to obtain the desired printed circuit board. In terms of structure, the circuit pattern is formed by electroplating to protrude from the surface of the underlying substrate.

However, in practical applications, the multiple switching knobs are used for various function switching, for example, applied to an audio or digital camera, and are mechanically contacted with each other mainly by rotation between a knob and the underlying circuit substrate structure to achieve multiple switching. purpose. However, if the conventional circuit pattern is used to protrude from the surface of the underlying substrate, the circuit pattern on the substrate structure is liable to be worn and damaged with long-term use.

In view of the above, one of the objects of the embodiments of the present invention is to provide a method for fabricating a circuit substrate structure having a smooth surface, such that the surface of the patterned circuit structure is flush with the surface of the prepreg substrate to enhance the durability of the multiple switching knobs. And reliability.

According to an embodiment of the present invention, a method of fabricating a circuit substrate having a smooth surface includes: providing a carrier; attaching a copper foil to the carrier; forming a photoresist layer on the copper foil and implementing a lithography process on the photoresist layer to expose a surface of the copper foil having a circuit pattern; forming a cladding layer on the surface of the copper foil having the circuit pattern; forming a copper plating layer on the cladding layer, Forming a patterned circuit structure; removing the photoresist layer to expose the underlying copper foil; pressing a prepreg with the carrier having the patterned circuit structure into a stack; removing the carrier and the carrier a copper foil; and stamping the prepreg to form a circuit substrate structure having a smooth surface.

According to another embodiment of the present invention, a method of fabricating a circuit substrate having a smooth surface includes: providing a carrier having a bonding layer; attaching a copper foil to the carrier; forming a photoresist layer thereon Forming a lithography process on the copper foil to expose a surface of the copper foil having a circuit pattern; plating a gold layer on the surface of the copper foil having the circuit pattern; plating a nickel layer on the gold Forming a copper plating layer on the nickel layer to form a patterned circuit structure; removing the photoresist layer to expose the underlying copper foil; performing a blackening treatment on the copper plating layer and the copper foil, To increase the surface roughness; compressing a prepreg and the carrier having the patterned circuit structure into a stack; removing the carrier and the copper foil to expose the surface of the gold layer; and stamping the prepreg to form A circuit board structure with a smooth surface.

In order to make the invention more apparent, the following detailed description of the embodiments and the accompanying drawings are as follows:

The following is a detailed description of the embodiments and examples accompanying the drawings, which are the basis of the present invention. In the drawings or the description of the specification, the same drawing numbers are used for similar or identical parts. In the drawings, the shape or thickness of the embodiment may be expanded and simplified or conveniently indicated. In addition, the components of the drawings will be described separately, and it is noted that the components not shown or described in the drawings are known to those of ordinary skill in the art, and in particular, The examples are merely illustrative of specific ways of using the invention and are not intended to limit the invention.

According to a main embodiment and aspect of the present invention, a method of fabricating a circuit substrate structure is provided, in which a patterned circuit structure is embedded in a prepreg substrate to have a smooth circuit surface. In an embodiment, a method for manufacturing a circuit substrate structure of a reverse manufacturing process is provided. The patterned circuit laminate structure is formed on a carrier plate with a copper foil in an opposite order, and the carrier is pre-impregnated. The material substrate is bonded, and the copper foil carrier is subsequently removed, ie, the patterned circuit structure is embedded in the prepreg substrate. Another embodiment of the present invention provides a circuit substrate structure having a patterned circuit structure embedded in a prepreg substrate such that the surface of the patterned circuit structure is flush with the surface of the prepreg substrate.

1-14 show schematic views of various stages of a method of fabricating a circuit substrate structure having a smooth surface in accordance with an embodiment of the present invention. Referring to FIG. 1, a carrier board, such as an epoxy resin (FR-4), a benzene resin, or a bismalelider triazine resin, is first provided. A layer of copper foil was laminated on the surface of the insulating substrate to form a copper-clad layer substrate as a starting material of the present embodiment. In another embodiment, a ring of adhesive layer 102 can be pressed onto the blank carrier 100. Next, a copper foil 104 is attached to the carrier 100. Since the carrier 100 has a ring of adhesive layers 102, the copper foil 104 can be more closely attached to the carrier, as shown in FIG.

Referring to FIG. 3, a photoresist layer 106 is formed on the copper foil 104. For example, in an embodiment, the steps of brushing, micro-etching, etc. may be performed, the surface copper foil is appropriately roughened, and the dry film photoresist 106 is closely adhered to the copper foil at an appropriate temperature and pressure. The surface of 104. Next, a lithography process is performed on the photoresist layer, that is, an exposure and development step is performed to expose a surface of the copper foil 104a having a circuit pattern, as shown in FIG.

Next, referring to FIG. 5, a cladding layer is formed on the surface of the copper foil having the circuit pattern. In one embodiment, the cladding layer includes a gold plating layer 108 and a nickel plating layer 110. In another embodiment, a gold plating layer 108 may be plated on the surface of the copper foil 104a having the circuit pattern, and a nickel plating layer 110 may be plated on the surface of the gold plating layer 108, as shown in FIG. It should be noted that the gold plating 108 may alternatively be other surface treatment layers including, for example, but not limited to, tin or silver.

Referring to FIG. 7, a copper plating layer is formed on the cladding layer to form a patterned circuit structure. In one embodiment, a copper plating layer 112 having a thickness of substantially 10 microns is formed on the nickel plating layer 110 to form a patterned circuit structure 115. Next, the photoresist layer 106 is removed, for example, the photoresist is removed by a photoresist removal solution (for example, an alkaline solution such as an aqueous NaOH solution) to expose the underlying copper foil 104, as shown in FIG.

Referring to FIG. 9, a blackening treatment is performed on the copper plating layer 112 and the copper foil 104 to increase the surface roughness, and then a prepreg 120 and the carrier 100 having the patterned circuit structure 115 are pressed into a stack. Body 150 is shown in FIG. For example, the stacked body 150 is hardened and bonded to the vacuum laminator at an appropriate temperature and pressure. Before the embossing step, the carrier 100 having the patterned circuit structure 115 may be subjected to a blackening (ie, oxidation) treatment to roughen the copper surface of the copper plating layer 112 and the copper foil 104 to increase the prepreg and The bonding force between the carriers having the patterned circuit structure. It should be noted that in order for the pressing step to proceed smoothly, an additional copper foil 130 (or other removable material such as a release film) may be placed on the outside of the prepreg 120, and the laminated body 150 after pressing. As shown in Figure 11.

Referring to FIG. 12, the carrier 100 and the copper foil 104 are removed to expose the surface 108b of the gold plating layer 108 such that the surface of the patterned circuit structure is flush with the surface of the prepreg substrate. After the step of removing the carrier and the copper foil, an additional gold plating layer 122 is additionally plated on the gold plating layer, and the required thickness can be plated at the beginning, as shown in FIG. Next, referring to FIG. 14, the prepreg is stamped into a desired shape 120a to form a circuit substrate structure 200 having a smooth surface.

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

100. . . Carrier board

102. . . Bonding layer

104. . . Copper foil

104a. . . The copper foil surface having a circuit pattern

106. . . Photoresist layer

108. . . Gold plating

108b. . . Gold plated surface

110. . . Nickel plating

112. . . Copper plating

115. . . Patterned circuit structure

120. . . Prepreg

120a. . . Prepreg of the desired shape

122. . . Extra gold plating

130. . . Extra copper foil

150. . . Stack

200. . . Circuit substrate structure with smooth surface

1-14 are schematic views showing the construction of a method of fabricating a circuit substrate having a smooth surface at various stages in accordance with an embodiment of the present invention.

120a. . . Prepreg of the desired shape

122. . . Extra gold plating

200. . . Circuit substrate structure with smooth surface

Claims (7)

A method for manufacturing a circuit board structure having a smooth surface, comprising: providing a carrier; attaching a copper foil to the carrier; forming a photoresist layer on the copper foil and performing a lithography process on the photoresist layer a surface of the copper foil having a circuit pattern; forming a coating layer on the surface of the copper foil having the circuit pattern; forming a copper plating layer on the coating layer to form a patterned circuit structure; Removing the photoresist layer to expose the underlying copper foil; pressing a prepreg with the carrier having the patterned circuit structure into a stack; removing the carrier and the copper foil; and stamping the prepreg The material is formed into a circuit substrate structure having a smooth surface. The method of manufacturing a circuit board structure having a smooth surface according to claim 1, wherein the carrier has a bonding layer to more closely adhere the copper foil to the carrier. The method of manufacturing a circuit board structure having a smooth surface according to claim 1, wherein the cladding layer comprises a gold plating layer and a nickel plating layer. A circuit board having a smooth surface as described in claim 1 The manufacturing method of the structure further comprises performing a blackening treatment before the pressing step to increase the bonding force between the prepreg and the carrier having the patterned circuit structure. The method for manufacturing a circuit board structure having a smooth surface according to claim 1, wherein after the step of removing the carrier and the copper foil, an additional gold plating layer is additionally plated on the gold plating layer. A method for manufacturing a circuit substrate structure having a smooth surface, comprising: providing a carrier having a bonding layer; attaching a copper foil to the carrier; forming a photoresist layer on the copper foil and performing a lithography process The photoresist layer is formed to expose a surface of the copper foil having a circuit pattern; a gold layer is plated on the surface of the copper foil having the circuit pattern; a nickel layer is plated on the surface of the gold layer; and a copper plating layer is formed Forming a circuit structure on the nickel layer; removing the photoresist layer to expose the underlying copper foil; performing a blackening treatment on the copper plating layer and the copper foil to increase surface roughness; The prepreg is pressed into a stack with the carrier having the patterned circuit structure; the carrier and the copper foil are removed to expose the surface of the gold layer; and the prepreg is stamped to form a circuit substrate structure having a smooth surface . The method for manufacturing a circuit board structure having a smooth surface according to claim 6, wherein after the step of removing the carrier and the copper foil, an additional gold plating layer is additionally plated on the gold plating layer.