Wiring Substrate Adhesion via Sequential Alkali and Ultrasonic Cleaning
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Solution Overview
Problem
The adhesion between the wiring layer and the insulating layer in wiring substrates is compromised when fillers in the insulating layer fall off during plating pre-treatment, leading to poor seed layer formation and reduced electrolytic plating growth, which affects the reliability of the connection between the wiring and insulating layers.
Innovation Solution
A manufacturing method that includes a first alkali treatment, ultrasonic cleaning, and a second alkali treatment on the inner surfaces of the opening portions and upper surfaces of the insulating layer to ensure uniform seed layer formation and prevent filler loss, followed by electrolytic plating to form a second wiring layer that extends from the inside of the opening portions to the upper surface of the insulating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plating pre-treatment is performed on the insulating layer, then the seed layer is formed for electrolytic plating, but the fillers in the insulating layer fall off during the process
Solution Approach 1:
The patent applies a specific sequence of pre-treatment steps (first alkali treatment, ultrasonic cleaning, second alkali treatment) before seed layer formation to prepare the surface in advance. This preliminary action removes contaminants and activates the surface without causing filler detachment, enabling subsequent uniform seed layer formation while preventing the harmful effect of filler loss.
2Ease of manufacture
If fillers fall off during plating pre-treatment, then the plating pre-treatment cannot be performed in concave portions, but adhesion between the wiring layer and insulating layer is reduced
Solution Approach 1:
The patent changes the parameters of the alkali treatment by applying it in two separate stages with ultrasonic cleaning in between. The first alkali treatment softens the insulating layer surface, ultrasonic cleaning removes loosened fillers, and the second alkali treatment further prepares the surface. This parameter change ensures complete surface treatment including concave portions without filler detachment, maintaining both manufacturing ease and adhesion reliability.
3Device complexity
If conventional single-step alkali treatment is used, then the process is simple, but the seed layer does not attach uniformly and adhesion is poor
Solution Approach 1:
The patent segments the alkali treatment process into two distinct stages separated by ultrasonic cleaning. The first alkali treatment prepares the surface initially, ultrasonic cleaning removes contaminants and loosened fillers, and the second alkali treatment completes the surface preparation. This segmentation achieves uniform seed layer attachment and strong adhesion while keeping the process manageable through systematic division of steps.
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 method enhances the adhesion between the wiring and insulating layers, preventing voids and cracks, thereby improving the connection reliability and preventing conduction failures, especially in semiconductor packages.
Implementation Method 1
performing a first alkali treatment, ultrasonic cleaning, and a second alkali treatment on an upper surface of the insulating layer, on an inner wall surface of the opening portion, and an upper surface of the first wiring layer
Implementation Method 2
an electrolytic plating is selectively performed using the seed layer as an underlying base, so that an electrolytic plated layer is formed
Data Source
AI summary
An insulating layer containing fillers is formed to cover a first wiring layer. An opening portion, in which the first wiring layer is exposed, is formed in the insulating layer. A first alkali treatment, an ultrasonic cleaning treatment, and a second alkali treatment are sequentially performed on an upper surface of the insulating layer, on an inner wall surface of the opening portion, and an upper surface of the first wiring layer exposed in the opening portion. A second wiring layer electrically connected to the first wiring layer is formed by filling the opening portion by plating. The second wiring layer extends from an inside of the opening portion to the upper surface of the insulating layer.