Manufacturing method for multi-layer circuit board

#1. Field of the Invention

#The invention relates to a manufacturing method for a circuit board, and particularly relates to a manufacturing method for a multi-layer circuit board.

#2. Description of Related Art

#The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

#FIGS. 1A to 1G are schematic views illustrating a process flow of a manufacturing method for a multi-layer circuit board according to an embodiment of the invention.

#FIG. 2 is a top view illustrating a substrate and a first patterned circuit layer according to an embodiment of the invention.

#Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

#FIGS. 1A to 1G are schematic views illustrating a process flow of a manufacturing method for a multi-layer circuit board according to an embodiment of the invention. FIG. 2 is a top view illustrating a substrate and a first patterned circuit layer according to an embodiment of the invention. In this embodiment, the manufacturing method for the multi-layer circuit board includes the following steps. First, as shown in FIG. 1A, a substrate 110 is provided. The substrate 110 includes surfaces 112 and 114 opposite to each other and a first via 116 connecting the surfaces 112 and 114. Then, referring to FIGS. 1B and 2, a first patterned circuit layer 120 is formed on each of the surfaces 112 and 114 by using the first via 116 as an alignment target. In this embodiment, as shown in FIG. 2, an outer diameter D1 of the first via 116 substantially ranges between 0.5 mm and 0.8 mm. It should be noted that the views of the process flow shown in FIGS. 1A to 1G are sectional views of a process flow in an area A of FIG. 2. As shown in FIG. 2, the first patterned circuit layer 120 includes a first concentric-circle pattern 122 surrounding the first via 116. The first concentric-circle pattern 122 includes a plurality of concentric circles, and an interval G1 between any two of the concentric circles substantially ranges between 50 μm to 100 μm. However, the invention is not limited thereto. People having ordinary skills in the art may make adjustments accordingly according to the design and layout of the product.

#Then, as shown in FIG. 1C, a first stacking layer 130 is formed on each of the surfaces 112 and 114. The first stacking layer 130 includes a first dielectric layer 132 and a first circuit layer 134, and the first circuit layer 134 covers the first dielectric layer 132. Then, referring to FIGS. 1D and 1E together, a first through hole 140 is formed by using CO2 laser drilling, for example. As shown in FIG. 1E, the first through hole 140 penetrates regions of the first stacking layer 130 and the substrate 110 where an inner diameter of a first concentric circle 122a from a center of the concentric-circle pattern 122 is orthogonally projected on. FIG. 3 is a top view that shows the first concentric-circle pattern 122 penetrated by the first through hole 140.