Composite Bond Wire with Outer Conductive Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing demand for complex electronics has led to a rise in the cost of precious metals used in wire bonding for semiconductor devices due to limited supply, making the manufacturing process costly and challenging.
Innovation Solution
The development of composite bond wires with a lower conductivity inner portion and a higher conductivity outer layer, where the thickness and material of the outer layer are determined by the expected frequency of signals to reduce metal content and cost, utilizing a mixture of conductive materials and submicron ceramic particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precious metals (gold, aluminum, copper, palladium-alloy, platinum, silver) are used for wire bonding to ensure conductivity and reliability, then the electrical performance and bonding quality are improved, but the material cost increases significantly due to limited supply and rising demand
Solution Approach 1:
The patent applies composite materials by creating a bond wire structure with an inner core of less expensive material (such as ceramic particles mixed with conductive material or lower-conductivity metal) and an outer layer of precious metal. This composite structure maintains the essential bonding and electrical properties at the wire surface while reducing the overall quantity of expensive materials required, thereby lowering material cost while preserving reliability.
Solution Approach 2:
The patent implements local quality by concentrating the precious metal material only where it is most needed - at the outer surface of the bond wire where electrical contact and bonding occur. The inner portion uses less expensive materials, creating a gradient of material quality that optimizes performance at the critical interface while minimizing material cost in the bulk of the wire.
2Reliability
If the cross-sectional area of bond wires is increased to reduce electrical resistance, then the electrical conductivity is improved, but the amount of precious metal material required increases, leading to higher costs
Solution Approach 1:
The patent uses composite materials to create a bond wire where the outer layer consists of highly conductive precious metal and the inner core consists of less expensive material with lower conductivity. This structure allows the wire to achieve the required electrical conductivity performance with a smaller cross-sectional area of expensive material, since the current primarily flows through the conductive outer layer.
Solution Approach 2:
The patent applies parameter changes by optimizing the thickness and material composition of the outer conductive layer based on the specific electrical performance requirements. By adjusting parameters such as layer thickness, material composition, and conductivity, the patent achieves the necessary electrical conductivity while minimizing the quantity of precious metal used.
3Adaptability or versatility
If the number of wire bonds is increased to accommodate higher-function devices with more bonding pads, then the device functionality is improved, but the total consumption of precious metal materials increases, exacerbating cost and supply issues
Solution Approach 1:
The patent applies composite materials to each individual bond wire in the multi-wire system, with each wire having an outer layer of precious metal and an inner core of less expensive material. This allows the system to support a high number of wire bonds for complex device functionality while reducing the total precious metal consumption across all wires, as each wire uses less expensive material in its core.
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 approach reduces the metal content and cost of bond wires while maintaining necessary conductivity, particularly effective at high frequencies where less of the wire's cross-sectional area is relevant to effective resistance, thus addressing the cost and complexity issues in semiconductor device packaging.
Implementation Method 1
A conductive material is melted and mixed with a ceramic material to create a mixture of the conductive material and the ceramic material
Data Source
AI summary
Bond wires for integrated circuits are implemented using a variety of methods. Using one such method, a composite bond wire is produced for use in an integrated circuit. A conductive material is melted and mixed with a material of particles less than 100 micrometers in size to create a mixture. The mixture is used to create the composite bond wire. A composite wire having an inner core and an outer layer having a higher conductivity than the inner core is also provided. The outer layer is designed to be thicker than the skin depth at the operating frequency for carrying AC signals.