PCB Buried Circuit Stiffness via Chemical Mechanical Etching
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Solution Overview
Problem
Existing printed circuit boards (PCBs) with buried circuit patterns face issues of plating variation and non-uniform etching, leading to potential short circuits and signal transmission errors due to the structure of the base circuit pattern and contact parts.
Innovation Solution
A method involving chemical mechanical etching to form micro-buried patterns without glass fibers, allowing for precise formation of circuit patterns and maintaining stiffness through a core insulating layer with glass fibers, while using a laser trench structure for groove formation to simplify manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a buried circuit pattern is formed through plating scheme, then adhesive strength with insulating member is improved, but plating variation occurs between regions with and without pattern grooves leading to non-uniform etching
Solution Approach 1:
The patent applies local quality by forming the circuit pattern through selective plating only in groove regions, while leaving non-groove regions with different surface properties. This creates localized differences in plating characteristics that naturally prevent uniform plating across the entire surface, thereby avoiding the plating variation problem that causes etching non-uniformity.
2Reliability
If circuit pattern protrudes from insulating layer through etching or plating, then circuit connection is achieved, but total thickness of PCB is increased limiting micro-circuit formation
Solution Approach 1:
The patent embeds the circuit pattern within grooves formed in the insulating layer, creating a nested structure where the conductive pattern is contained within the insulating material. This nesting approach allows the circuit to be formed without increasing the overall PCB thickness, enabling micro-circuit formation while maintaining reliable electrical connections.
3Length of stationary object
If thin insulating layer is formed for buried pattern, then total thickness is reduced, but stiffness may be compromised
Solution Approach 1:
The patent employs composite materials by combining the thin insulating layer containing the buried circuit pattern with additional structural support layers. This composite structure allows the PCB to maintain reduced overall thickness while the combination of materials provides the necessary stiffness and mechanical strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the formation of thin, stiff PCBs with reduced plating errors and uniform etching, preventing shorts between adjacent patterns and ensuring accurate signal transmission.
Implementation Method 1
the micro-buried pattern can be simply formed by removing the plating layer on the insulating layer through the chemical mechanical etching
Implementation Method 2
forming the circuit pattern by filling the groove of the substrate through a plating scheme
Implementation Method 3
a laser trench structure is applicable when the groove for the buried pattern is formed
Data Source
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AI summary
Disclosed is a printed circuit board. The printed circuit board includes: a core insulating layer including a glass fiber; a first insulating layer on an upper portion or a lower portion of the core insulating layer, the first insulating layer including a circuit pattern groove; a first circuit pattern filling the circuit pattern groove of the first insulating layer; a second insulating layer covering the first circuit pattern and including a circuit pattern groove at a top surface thereof; and a second pattern filling the circuit pattern groove of the second insulating layer, wherein the first insulating layer including a filler distributed in a resin material. Accordingly, the micro-buried pattern can be simply formed by removing the plating layer on the insulating layer through the chemical mechanical etching while forming the circuit pattern by filling the groove of the substrate through a plating scheme. In addition, the buried pattern can be formed while maintaining stiffness by the glass fiber of the core insulating layer by forming the buried pattern in the insulating layer after bonding the insulating layer formed of resin including the filler on the core insulating layer. As described above, a total thickness of the PCB can be thinly formed while maintaining the stiffness by separately forming a thin insulating layer without a glass fiber for the buried pattern on the core insulating layer.