Wiring Substrate CuNiTi Interface for Filler-Exposed Adhesion
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Solution Overview
Problem
The adhesion between insulation layers and wiring layers in wiring substrates decreases when the filler in the insulation layer is exposed, leading to potential delamination issues.
Innovation Solution
A wiring substrate design that includes a first metal film formed from a CuNiTi alloy with specific content rates of Ni (5-30 wt%) and Ti (5-15 wt%) to enhance adhesion to both the resin and fillers, ensuring strong bonding with the insulation layer, and a manufacturing process that uses sputtering and electrolytic plating to form the metal films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulation layer includes filler exposed from the resin surface, then the insulation layer can provide good electrical insulation and mechanical strength, but the adhesion between the insulation layer and wiring layer decreases
Solution Approach 1:
The patent segments the metal film into multiple functional layers: a first metal film (CuNiTi alloy) that provides adhesion to the filler-exposed insulation layer, and a second metal film (Cu alloy) that provides electrical conductivity and solderability. This segmentation allows each layer to be optimized for its specific function, resolving the adhesion problem while maintaining manufacturing feasibility
Solution Approach 2:
The patent uses composite materials by combining Cu, Ni, and Ti in specific proportions (Cu: 70-85 wt%, Ni: 5-30 wt%, Ti: 5-15 wt%) to create a first metal film with enhanced adhesion properties. This composite alloy structure enables strong bonding to the filler-exposed insulation layer surface, overcoming the adhesion deficiency caused by filler exposure
2Reliability
If a CuNiTi alloy first metal film is used to enhance adhesion, then the adhesion between metal film and insulation layer improves, but the manufacturing cost increases due to additional alloy components
Solution Approach 1:
The patent applies local quality by using the expensive CuNiTi alloy only in the first metal film layer that directly contacts the filler-exposed insulation layer, where adhesion is critical. The second metal film uses a more cost-effective Cu alloy since it primarily needs electrical conductivity and solderability. This localized material selection optimizes adhesion where needed while controlling overall material costs
3Productivity
If the first metal film is formed with specific Ni and Ti content ranges, then simultaneous etching with Cu etching liquid becomes feasible, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise parameter ranges for the CuNiTi alloy composition (Cu: 70-85 wt%, Ni: 5-30 wt%, Ti: 5-15 wt%) to enable simultaneous etching with Cu etching liquid. These parameter changes are carefully controlled to ensure that the first metal film can be removed together with the second metal film in a single etching step, improving manufacturing efficiency while maintaining feasible precision requirements through clear specification boundaries
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
The CuNiTi alloy film effectively adheres to the insulation layer, preventing delamination and facilitating efficient etching, thereby enhancing the structural integrity and manufacturing efficiency of the wiring substrate.
Implementation Method 1
The first metal film is formed from a CuNiTi alloy... The CuNiTi alloy ensures higher adhesion between the metal film and the insulation layer
Implementation Method 2
facilitates cost-effective manufacturing by allowing for simultaneous removal of unnecessary metal film parts with a Cu etching liquid
Data Source
AI summary
A wiring substrate includes a first wiring layer, an insulation layer covering a side surface of the first wiring layer and exposing part of the first wiring layer, and a second wiring layer formed on the first wiring layer exposed from the insulation layer. The insulation layer includes a resin and a filler. The insulation layer includes an upper surface having a structure in which the filler is exposed from the resin. The second wiring layer includes a first metal film, covering the upper surface of the insulation layer and the wiring layer exposed from the insulation layer, and a metal layer, formed above the first metal film. The first metal film is formed from a CuNiTi alloy and has a Ni content rate of 5 wt % or greater and 30 wt % or less and a Ti content rate of 5 wt % or greater and 15 wt % or less.