Rhodium Pb-Te-O Conductive Paste for Solar Cell Solder Adhesion

Solution Overview

Problem

Conventional solar cell electrode pastes struggle to achieve improved solder adhesion while maintaining electrical performance, which is crucial for the reliability and efficiency of solar cells.

Innovation Solution

An electrically conductive composition comprising an electrically conductive metal, a Rh-containing component, Pb—Te—O, and an organic medium, which is applied to a semiconductor substrate and fired to form electrodes with enhanced solder adhesion and electrical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional thick-film paste compositions are used, then the manufacturing process is simple and cost-effective, but solder adhesion is insufficient

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies composite materials by formulating a thick-film paste containing multiple components including Pb-Te-O glass frit, rhodium-containing component, electrically conductive metal particles, and organic vehicle. This composite composition achieves improved solder adhesion through the synergistic interaction of components, particularly Pb-Te-O glass frit that forms strong interfacial bonds between solder and substrate, while maintaining manageable manufacturing complexity

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent employs parameter changes by optimizing the chemical composition parameters of the paste, specifically incorporating Pb-Te-O glass frit with controlled ratios of PbO (40-70 wt%), TeO2 (20-50 wt%), and O (10-30 wt%). These compositional parameter adjustments enable enhanced solder adhesion properties while maintaining processability and electrical performance

Inventive Principle:

Principle #35Parameter changes

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 composition effectively forms electrodes with improved solder adhesion and maintains electrical performance, enhancing the reliability and efficiency of solar cells.

Implementation Method 1

firing the article and the composition wherein the organic medium of the thick film paste is volatilized, thereby forming the electrode

Methodology Applied

Scientific EffectVolatilization: Evaporation

Implementation Method 2

the glass frit and any added flux reacts with and etches through the anti-reflective coating and facilitates the formation of intimate silicon-electrode contact

Methodology Applied

Scientific EffectEtching: Chemical Bonding

Implementation Method 3

facilitates the formation of intimate silicon-electrode contact

Methodology Applied

Scientific EffectChemical bonding: Chemical Bonding

Data Source

PatentUS8916069B2Conductive compositions containing rhodium and Pb-Te-O and their use in the manufacture of semiconductor devices

Publication Date: 2014.12.23

AI summary

The present invention is directed to an electrically conductive composition comprising (a) an electrically conductive metal; (b) a Rh-containing component; (c) a Pb—Te—O; and (d) an organic medium; wherein the electrically conductive metal, the Rh-containing compound, and the Pb—Te—O are dispersed in the organic medium. The present invention is further directed to an electrode formed from the composition and a semiconductor device and, in particular, a solar cell comprising such an electrode. Also provided is a process for forming such an electrode. The electrodes provide good adhesion and good electrical performance.