Core Issues and Technical Background:
Pengding Holdings addresses the trend of existing electronic products moving towards being thinner, lighter, and smarter, where flexible circuit boards (FPC) are widely used as important components. To achieve high frequency, high speed, thinness, and dense routing, as well as to meet the requirements of Ball Grid Array (BGA) packaging, the connection between the solder pads (solder pads) and the pads inside the array needs to be routed between the lines, which increases the spacing between the pads, thus limiting the high-density trend of the pads.
Main Innovations/Solutions:
Pengding Holdings provides a circuit board with solder pads and its manufacturing method, aimed at solving the above technical issues and achieving a high-density arrangement of solder pads.
Main Technical Features (according to the claims and description):
Circuit Board Structure:
Includes at least three conductive layers.
The circuit board includes a first surface, on which a first conductive layer and multiple solder pads are formed.
The multiple solder pads are arranged in a matrix to form a solder pad matrix, which includes multiple outer solder pads at the periphery and multiple center solder pads surrounded by the outer solder pads.
The outer solder pads are electrically connected to the first conductive layer, while the center solder pads are independently formed on the first surface.
Innovative Connection Method:
The outer solder pads are connected to the first conductive layer through conductive vias.
Center solder pads: The innovation lies in that the electrical connection method of the center solder pads to the first conductive layer is different from that of the outer solder pads.
Pengding Holdings proposes that the center solder pads may not be connected to the first conductive layer.
Alternatively, the center solder pads can be connected to the second or third conductive layers through conductive vias.
Importantly, the center solder pads can communicate with the second and third conductive layers through conductive vias, maximizing the density of solder pads on the surface of the circuit board, even if there are no solder pad leads passing between the pads.
Specifically, the center solder pads can connect to the same center solder pad through the first or second conductive vias. The first conductive via connects to the outer solder pads, and the first conductive via does not connect to the same center solder pad as the second conductive via at the same time.
Key Points of the Manufacturing Method:
Provide a first circuit substrate, which includes a first substrate layer and a first copper foil and a second copper foil located on the opposite surfaces of the first substrate layer.
Form the second conductive layer from the second copper foil.
Provide a second circuit substrate, which includes a third copper foil and a second substrate layer, and press the second circuit substrate together with the first circuit substrate to form a multilayer board, with the third conductive layer located between the first substrate layer and the second substrate layer.
Form multiple first conductive vias and multiple second conductive vias on the multilayer board, where the first conductive vias penetrate the first copper foil and the first substrate layer and are electrically connected to the second conductive layer, and the second conductive vias penetrate the multilayer board and are electrically connected to the second copper foil, the second conductive layer, and the third copper foil.
Form the first conductive layer and multiple solder pads from the first copper foil, and form the third conductive layer from the third copper foil.
Manufacture the solder pad matrix, including outer solder pads and center solder pads. The outer solder pads are electrically connected to the first conductive layer, and the center solder pads are independently formed on the first surface.
Specific Processing Method: The method for forming the first and second conductive vias can be laser drilling or deep mechanical drilling to form multiple blind holes, and conductive materials are filled into the blind holes through electroplating or printing conductive paste to form the first and second conductive vias.
A metal protective layer is formed on the surface of the solder pads, which can be made of nickel, gold, or nickel/gold alloy.
A solder mask layer is formed on all areas of the circuit board except for the solder pads.
Key Concepts/Facts:
The core of Pengding Holdings lies in breaking the traditional solder pad lead routing mode by adjusting the connection method between the solder pads (especially the center solder pads) and the circuit layers, thereby increasing the density of solder pads on the surface of the circuit board.
By connecting some solder pads (center solder pads) to deeper conductive layers, more space can be left on the surface layer for other routing or directly increase the number of solder pads.
This technical solution is particularly suitable for high-density packaging, such as BGA packaging, and can meet the demand for miniaturization and high integration of consumer electronic products.
Through detailed descriptions of the manufacturing steps, Pengding Holdings provides a feasible method for achieving the aforementioned high-density solder pad circuit board, including lamination of multilayer boards, formation of conductive vias (laser or mechanical drilling), filling conductive materials, and surface treatment (metal protective layer and solder mask layer).
Key Quotes:
In view of this, it is necessary to provide a circuit board and its manufacturing method that can solve the above technical problems.” (Indicates the core issues that need to be addressed)
At least three conductive layers; the circuit board includes a first surface, on which a first conductive layer and multiple solder pads are formed;” (Describes the basic structure of the circuit board)
The multiple solder pads are arranged in a matrix to form a solder pad matrix, which includes multiple outer solder pads at the periphery and multiple center solder pads surrounded by the outer solder pads, where the outer solder pads are electrically connected to the first conductive layer, and the center solder pads are independently formed on the first surface.” (Describes the arrangement of solder pads and their connection to the first conductive layer)
The formation directions of the first conductive vias and the second conductive vias can be the same or opposite.” (Mentions the flexibility of the direction of conductive vias)
No conductive vias connect to the outer solder pads, and the first conductive vias and the second conductive vias do not connect to any center solder pad at the same time.” (Emphasizes the difference in connection methods for center solder pads)
That is to say, using the first conductive via 304 or the second conductive via 305 to direct the center solder pad 116 to the second conductive layer 130 or the third conductive layer 210, in the solder pad matrix 112, only the leads of the outer solder pad 114 closest to the first conductive layer 110 will occupy the surface area of the first conductive layer 110, while the leads of the center solder pad 116 direct to the second conductive layer 130 or the third conductive layer 210 outside of the first conductive layer 110, thus reducing the need for solder pad leads within the solder pad matrix 112, meaning that more solder pads can be set up on the same area of the circuit board, achieving high density of solder pads and high integration of the circuit board, meeting the direction of consumer electronic products towards miniaturization and intelligence.” (Elaborates on the core advantages of achieving high-density solder pads by connecting center solder pads to deeper layers)
Potential Applications:
High-density packaging field, especially flexible circuit boards for BGA packaging. Suitable for various consumer electronic products that require high integration, miniaturization, and high-speed performance.
Summary:
Pengding Holdings provides an innovative circuit board structure with solder pads and its manufacturing method, focusing on the differentiated treatment of the connection methods between solder pads and conductive layers, especially connecting some center solder pads to deeper layers, effectively increasing the density of solder pads on the surface of the circuit board, meeting the modern electronic products’ demand for high integration and miniaturization. This technology is significant for promoting the application of flexible circuit boards in high-performance fields.
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