Two-Layer Insulating Adhesive for IC Chip Bump Connection
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Solution Overview
Problem
In the context of semiconductor connections, the miniaturization of IC chips leads to narrower pitches and gaps, causing issues such as void formation and increased conduction resistance due to the trapping of fillers between electrodes and substrates, especially in three-dimensional laminated structures with low solder bumps, which compromises the reliability of the connection.
Innovation Solution
A connection method using a two-layer insulating adhesive member, where a first layer with a filler is opposed to the electrode of the electronic component, and a second layer without a filler is used to ensure that the filler is not trapped between the electrodes, with the thickness ratio of the first layer to the second layer controlled such that H/2 < Tf < H ≤ Tf + Tn, where H is the electrode height, Tf is the first layer thickness, and Tn is the second layer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filler-containing adhesive is used to decrease linear expansion coefficient and prevent delamination, then reliability is improved, but filler particles are trapped between electrodes during connection, causing increased conduction resistance
Solution Approach 1:
The adhesive layer is segmented into two distinct layers: a first adhesive layer containing filler particles (for mechanical support and thermal expansion matching) and a second adhesive layer free of filler particles (for electrical conduction). This segmentation allows each layer to perform its specific function without interference, resolving the contradiction between reliability and conduction resistance
Solution Approach 2:
Different regions of the adhesive structure are assigned different qualities: the first adhesive layer has high filler content for structural stability and low linear expansion coefficient, while the second adhesive layer has no filler for optimal electrical conductivity. This local differentiation of material properties enables simultaneous achievement of mechanical reliability and electrical performance
2Manufacturing precision
If the thickness of the adhesive layer is increased to ensure complete coverage, then manufacturing precision is improved, but the risk of filler trapping between electrodes increases
Solution Approach 1:
The adhesive system is divided into two layers with distinct functions: the first layer provides coverage and structural support with filler, while the second filler-free layer ensures electrode contact without trapping particles. This segmentation allows adequate thickness for coverage while preventing filler interference with electrical connection
Solution Approach 2:
The second adhesive layer acts as an intermediary between the filler-containing first layer and the electrodes. It provides a clean, particle-free interface that facilitates direct electrode contact while the first layer maintains overall structural integrity and coverage
Data Source
AI summary
An insulating adhesive film is formed by laminating a first insulating adhesive layer which contains a filler in an insulating adhesive composition and a second insulating adhesive layer which contains no filler in an insulating adhesive composition. H/2<Tf<H≦̸Tf+Tn is satisfied, wherein H is the height of the bump of the IC chip, Tf is the thickness of the first insulating adhesive layer, and the Tn is the thickness of the second insulating adhesive layer. The side of the substrate on which an electrode is formed and the side of an IC chip on which a bump is formed are connected via the insulating adhesion film arranged such that the first insulating adhesive layer and the electrode-forming side of the electronic component are opposed to thereby connect the electrode of the substrate and the bump of the IC chip.