Thin-Film Wiring Substrate Bonding Layer Deformation Control
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Solution Overview
Problem
The existing thin-film wiring substrates face issues with deformation of the resin bonding layer under pressure, which can hinder electrical connections between the ceramic substrate and the thin-film wiring layer, leading to potential disconnections during semiconductor testing.
Innovation Solution
A bonding layer with a core layer of high elastic modulus thermosetting resin and adhesive layers of lower elastic modulus thermosetting resin is used, where the core layer suppresses deformation and maintains adhesion, preventing resin material from entering between the via conductor and the thin-film wiring layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a resin bonding layer is used to bond the thin-film wiring layer to the ceramic substrate, then productivity and ease of manufacture are improved, but the resin material deforms under pressure during bonding or testing, causing it to enter between the via conductor and the thin-film wiring layer, which worsens electrical connection reliability
Solution Approach 1:
The bonding layer is segmented into multiple functional layers: a first adhesive layer for bonding to the ceramic substrate, a core layer with high elastic modulus to suppress deformation, and a second adhesive layer for bonding to the thin-film wiring layer. This segmentation allows each layer to perform its specific function optimally while maintaining overall reliability.
Solution Approach 2:
Different regions of the bonding layer have different properties tailored to local requirements. The core layer has high elastic modulus where structural stability is needed, while the adhesive layers have appropriate bonding characteristics where adhesion is required. This local differentiation resolves the contradiction between ease of manufacture and electrical connection reliability.
2Strength
If pressure is applied during bonding of the thin-film wiring layer to the ceramic substrate, then bonding strength is improved, but the resin material stretches in the transverse direction and enters between the via conductor and the thin-film wiring layer, which worsens electrical connection
Solution Approach 1:
The elastic modulus parameter of the bonding layer materials is changed and optimized. The core layer uses material with high elastic modulus to resist transverse deformation under pressure, while the adhesive layers use materials with appropriate bonding parameters. This parameter optimization allows strong bonding without resin intrusion that would compromise electrical connection precision.
3Strength
If the bonding layer uses material with high adhesion to ensure bonding strength, then bonding reliability is improved, but the material is more prone to deformation under pressure, which worsens electrical connection stability
Solution Approach 1:
The bonding layer is divided into a core layer for structural stability and adhesive layers for bonding strength. This segmentation allows the core layer to maintain compositional stability under pressure while the adhesive layers provide the necessary bonding strength, resolving the contradiction between bonding strength and compositional stability.
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 configuration effectively secures electrical connections between the ceramic substrate and the thin-film wiring layer, enhancing reliability and maintaining adhesion, even under pressure, thus preventing disconnections and ensuring stable electrical performance.
Implementation Method 1
a core layer composed of a thermosetting resin and adhesive layers laminated on the upper and lower surfaces of the core layer and composed of a thermosetting resin having smaller elastic modulus than the thermosetting resin constituting the core layer
Implementation Method 2
a bonding layer including a core layer composed of a thermosetting resin and adhesive layers laminated on each of the upper and lower surfaces of the core layer
Data Source
AI summary
A thin-film wiring substrate includes a base B including a ceramic substrate having an upper surface and a wiring conductor provided on the upper surface of the ceramic substrate; a bonding layer and a thin-film wiring layer laminated in order on the upper surface of the ceramic substrate; and a through conductor that passes through the bonding layer in a thickness direction and electrically connects the wiring conductor to the thin-film wiring layer, Wherein the bonding layer includes a core layer composed of a thermosetting resin and adhesive layers respectively laminated on an upper surface and a lower surface of the core layer, the adhesive layers being composed of a thermosetting resin having an elastic modulus smaller than that of the thermosetting resin constituting the core layer.