Double-Sided Semiconductor Package Side Wiring via Ink Jet
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Solution Overview
Problem
Conventional double-sided electrode packages require through electrode structures, which are difficult to insulate due to high temperature processing, leading to high wiring resistance issues, especially with copper, where surface oxidation is a problem, and existing solutions like thermal treatment in inert gases are not effective for reducing resistance.
Innovation Solution
The use of nano copper metal particles with the ink jet system for side wiring, where atomic hydrogen is employed to reduce metal surface oxidation and remove organic matter, allowing for lower temperature processing and reduced resistance without the need for through holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal treatment is performed to vaporize organic solvent and adhere copper particles, then the organic solvent is removed and copper particles are mutually adhered, but the surface of copper ends up being oxidized and wiring resistance becomes high
Solution Approach 1:
The patent applies inert atmosphere by performing thermal treatment in an inert gas environment (nitrogen or rare gas) to prevent copper oxidation during the heating process. The inert gas displaces oxygen, creating an oxidation-free environment that allows copper particles to adhere without forming high-resistance oxide layers on their surfaces.
Solution Approach 2:
The patent optimizes thermal treatment parameters including temperature range (100-300°C), treatment time (1-30 minutes), and inert gas flow rate (10-1000 mL/min) to achieve complete organic solvent removal and copper particle adhesion while minimizing oxidation. By carefully controlling these parameters, the process achieves low wiring resistance without requiring additional reduction steps.
2Reliability
If high temperature processing is used for through electrode insulation, then insulation is achieved, but the mounting process becomes difficult and through hole formation problems persist
Solution Approach 1:
The patent extracts and eliminates the through hole structure entirely, replacing it with a side wiring approach that connects electrodes laterally through the substrate edge. This removes the need for high-temperature through hole insulation processing while achieving the same electrical isolation function through the ink jet deposited insulating material.
Solution Approach 2:
The patent replaces conventional high-temperature thermal insulation processes with a low-temperature ink jet deposition method. The insulating material is deposited directly onto the substrate surface at room temperature or low temperature, eliminating the need for high-temperature processing while maintaining effective insulation between electrodes.
3Quantity of substance
If conventional ink jet method with thermal treatment alone is used, then organic solvent is vaporized, but thermal treatment alone is unable to sufficiently remove the organic solvent and electric resistivity cannot be reduced
Solution Approach 1:
The patent optimizes multiple parameters including extending thermal treatment time (1-30 minutes), controlling temperature within 100-300°C range, and adjusting inert gas flow rate (10-1000 mL/min) to ensure complete organic solvent removal. These parameter optimizations enable sufficient solvent evaporation while preventing copper oxidation, achieving both complete removal and low resistivity simultaneously.
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 method enables the manufacture of double-sided electrode packages without through holes, reducing wiring resistance and enabling effective use in various applications, including sensors, with lower processing temperatures and costs, and adaptable to different chip sizes.
Implementation Method 1
the wiring by these nano copper metal particles performs a reduction of the metal surface oxidation film and/or removal processing of organic matters of the wiring by atomic hydrogen
Data Source
AI summary
The present invention connects a first wiring portion located at one side of a substrate and a second wiring portion located at the other side. A side electrode connected to the first wiring portion is formed, and the second wiring portion is formed on an insulating layer formed on the substrate. An exposed end of the second wiring portion formed when singulated into individual semiconductor package and the side electrode are wired by ink jet system using nano metal particles. Particularly, when copper is used, the wiring by the ink jet system is performed by the reduction of a metal surface oxidation film and/or removal of organic matters by atomic hydrogen.