Multilayer Circuit Board Tin Layer Galvanic Corrosion Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing tinning process for multilayer circuit boards can damage adhesive layers, solder mask, and wiring layers due to Galvanic Corrosion, leading to instability in the circuit board.
Innovation Solution
A method involving the formation of a tin layer on the entire surface of the inner wiring layer using electroless tin plating before attaching outer circuit boards, with defined gaps and subsequent surface treatments to prevent exposure and damage during the tinning process, ensuring the tin layer's integrity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an opening is defined to expose the region that needs to be tinned, then the tinning process can be applied directly, but the exposed adhesive layers, solder mask, and wiring layer may be damaged by Galvanic Corrosion
Solution Approach 1:
The patent applies preliminary action by forming a protective coating on the adhesive layers, solder mask, and wiring layers before the tinning process. This coating prevents Galvanic Corrosion during tinning, allowing the opening to be defined and tinning to proceed without damaging the exposed components. The protective coating is applied in advance to protect against the harmful effects that would occur during the subsequent tinning operation.
2Manufacturing precision
If the adhesive layers, solder mask, and wiring layer are exposed from the opening, then the tin layer can be formed, but the exposed components may suffer Galvanic Corrosion damage
Solution Approach 1:
The patent introduces an intermediary protective coating between the exposed components (adhesive layers, solder mask, wiring layer) and the tinning environment. This coating acts as a mediator that prevents direct contact between the exposed components and the corrosive conditions during tinning, thereby eliminating Galvanic Corrosion damage while allowing the tin layer to be formed accurately on the intended surfaces.
3Adaptability or versatility
If the multilayer circuit board is assembled using various technologies, then the circuit board can be manufactured with different functionalities, but the stability may decrease due to damage during tinning process
Solution Approach 1:
The protective coating is applied in advance before the tinning process, ensuring that regardless of which assembly technology is used subsequently (anisotropic conductive adhesive, Surface Mount Technology, etc.), the exposed components are already protected from Galvanic Corrosion. This preliminary protection maintains circuit board stability while allowing versatility in assembly methods.
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 enhances the stability and strength of the multilayer circuit board by preventing damage to the adhesive layers, solder mask, and wiring layers during the tinning process, allowing for reliable assembly using various technologies like anisotropic conductive adhesive and Surface Mount Technology.
Implementation Method 1
a method involving the formation of a tin layer on the entire surface of the inner wiring layer using electroless tin plating
Data Source
AI summary
A multilayer circuit board comprises an inner circuit board, a tin layer, at least one outer circuit board, and a solder mask. The inner circuit board comprises at least one first mounting region and at least one second mounting region. The tin layer is formed on a surface of the inner circuit board except the first mounting region connecting the outer circuit board. The outer circuit board comprises at least one first opening to expose the first mounting region and at least one second opening to expose a portion of the tin layer covering the second mounting region. The inner circuit board, the tin layer, and the outer circuit board together form a middle structure. The solder mask covers the middle structure except the portion and the first mounting region. A treatment layer is formed on the first mounting region.