Adhesive Layer Embedding Semiconductor Elements
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Solution Overview
Problem
The existing underfill process in semiconductor manufacturing is inefficient, leading to signal transmission inefficiencies and reduced manufacturing yield due to issues with adhesion and contamination, and it complicates high-density mounting and multistage stack packaging.
Innovation Solution
A semiconductor device and manufacturing method utilizing an adhesive layer with specific melt viscosity and thixotropic index, allowing for effective embedding of semiconductor elements without the need for underfill materials, enhancing signal transmission efficiency and manufacturing process efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid underfill material is used to fill the gap between chip and printed circuit board, then thermomechanical fatigue is reduced, but the liquid material protrudes to undesired portions causing contamination and product defects
Solution Approach 1:
The patent changes the viscosity parameter of the adhesive material from liquid state to paste state. The paste adhesive has higher viscosity than liquid underfill material, which prevents it from flowing to undesired portions while still filling the gap between the semiconductor element and substrate. This parameter change resolves the contradiction by maintaining thermomechanical fatigue resistance through proper gap filling while eliminating contamination and defect issues caused by material protrusion.
2Reliability
If underfill process is implemented to protect integrated circuits, then device protection is improved, but manufacturing process complexity and time increase
Solution Approach 1:
The patent merges the adhesive layer formation and underfill gap filling processes into a single step. The paste adhesive is applied to the substrate and simultaneously serves as both the adhesive layer for mounting the semiconductor element and the underfill material for filling the gap. This consolidation eliminates the need for separate underfill application and curing steps, reducing manufacturing process time while maintaining device protection functionality.
Solution Approach 2:
The paste adhesive material performs multiple functions: it acts as the adhesive layer for bonding the semiconductor element to the substrate, serves as the underfill material for filling and protecting the gap, and provides structural support. This multi-functionality eliminates the need for separate underfill materials and processes, streamlining manufacturing while ensuring device protection.
3Manufacturing precision
If existing underfill process is used, then gap filling is achieved, but signal transmission efficiency and manufacturing yield are reduced
Solution Approach 1:
The patent uses a paste adhesive that is a composite material containing inorganic particles dispersed in an adhesive matrix. This composite structure provides excellent gap filling capability while the inorganic particles improve thermal conductivity and electrical properties. The composite material formulation enhances signal transmission efficiency by reducing signal loss and improving electrical connectivity, while also increasing manufacturing yield through better process control and reduced defects compared to conventional liquid underfill materials.
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 solution enables improved signal transmission speed and manufacturing efficiency by eliminating the need for underfill materials, reducing contamination, and facilitating high-density mounting and multistage stack packaging.
Implementation Method 1
an adhesive layer for embedding a space between an adherend and the first semiconductor element and embedding the first semiconductor element; and a second semiconductor element connected to the first semiconductor element via the adhesive layer, wherein the adhesive layer has a melt viscosity of 10 to 10,000 Pa·s at a temperature of 110° C. and a shear rate of 5 rad/s, and wherein a thixotropic index defined by a ratio of the melt viscosity of the adhesive layer at a shear rate of 0.5 rad/sec and a temperature of 110° C. to the melt viscosity of the adhesive layer at a shear rate of 5 rad/sec and a temperature of 110° C. is 1.5 to 7.5
Data Source
AI summary
The present invention relates to a semiconductor device including: a first semiconductor element fixed onto an adherend by flip-chip connection; an adhesive layer for embedding a space between the adherend and the first semiconductor element and embedding the first semiconductor element; and a second semiconductor element connected to the first semiconductor element via the adhesive layer, wherein the adhesive layer has a predetermined melt viscosity and thixotropic index.