What is Blister
Blister is a localized swelling and separation that occurs between the layers of a laminated base material or between the base material and conductive foil. It is considered a form of delamination. This issue can also involve the separation of the solder mask layer and the conductive pattern on the PCB.
Blistering typically arises due to factors such as poor bonding force, contaminants present on the surface, and the micro-roughness or energy of the surface. When the bonding force between the coatings on the circuit board is insufficient, it becomes challenging for the coatings to withstand the stress generated during production and assembly processes. This stress can include coating stress, mechanical stress, and thermal stress. As a result, the coatings may separate to varying degrees, leading to the formation of blisters or bubbles on the surface of the circuit board.
Blistering may or may not result in a failure of the board, depending on the location and severity of the separation. However, it is generally considered a form of delamination and can impact the overall quality and reliability of the PCB.
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