Precious Metal Paste

High-Performance Conductive Pastes for Research & Industrial Applications from Eata Electronic

Figure 1: Silver conductive paste with printed thick-film circuit on ceramic substrate

Thick-film technology has long served as the backbone of hybrid microelectronics manufacturing, and at the heart of this process sits the precious metal paste — a carefully engineered suspension of fine metallic particles, glass frit, and organic vehicle that transforms into electrically functional traces, electrodes, and bonding layers when printed and fired onto ceramic or metal substrates. From the fine-line circuitry inside medical implantable devices to the robust heater elements on steel substrates, the quality of the conductive paste directly governs electrical performance, adhesion strength, solderability, and long-term reliability.

Eata Electronic offers an extensive selection of precious metal pastes formulated for screen printing, stencil dispensing, and syringe deposition across a broad spectrum of research and industrial uses. Our portfolio spans silver, gold, platinum, palladium, and binary or ternary alloy compositions such as silver-palladium, silver-platinum, and gold-platinum-palladium systems. Each formulation targets specific substrate compatibility, firing temperature ranges, electrical conductivity benchmarks, and post-fire processing requirements including wire bonding, soldering, or overglazing. Whether you are fabricating hybrid circuits on alumina, building sensor electrodes, producing chip resistor terminations, or attaching power semiconductor dies, our pastes deliver the consistency and performance that advanced electronic manufacturing demands.

Figure 2: Gold thick-film paste being screen-printed onto alumina ceramic substrate

Silver Conductive Pastes

Silver conductive pastes represent the workhorse of the thick-film conductor family, prized for the highest electrical and thermal conductivity among all printable metals. Pure silver pastes typically contain 60-85% metallic silver by weight, blended with a mixed-bonded glass frit system that promotes strong adhesion to alumina, glass, enamel-coated steel, and certain dielectric layers after firing at 500-850 degrees Celsius.

Silver Cermet Pastes

Our silver cermet pastes produce smooth, dense fired layers with excellent solderability using both lead-containing and lead-free solder systems. These formulations are widely adopted for chip resistor terminations, potentiometer conductive tracks, heater circuits on ceramic and steel substrates, and general-purpose interconnects on hybrid microcircuits. The fired film exhibits sheet resistance below 30 milliohms per square at 25 micrometer thickness, with strong leach resistance during solder immersion.

Low-Temperature Silver Pastes

For temperature-sensitive substrates such as soda-lime glass, float glass, and certain enamels that cannot withstand conventional high-fire cycles, we supply low-temperature silver pastes sintering at 525-600 degrees Celsius. These formulations maintain acceptable adhesion and conductivity while preventing substrate warpage, softening, or thermal damage. Applications include circuits on glass substrates, transparent heater elements, and decorative or functional metallization on consumer glassware.

Solderable Silver Pastes

Certain applications demand repeated solder reflow cycles without conductor degradation. Our solderable silver paste grades feature optimized glass chemistry and surface morphology that resist solder leaching even after multiple immersion cycles in SAC305 or Sn95/Ag5 solder baths. These pastes are essential for surface-mount compatible hybrid circuits, sensor modules requiring subsequent component attachment, and power device packages.

Gold Conductive Pastes

Gold conductor pastes occupy a unique position in the thick-film materials spectrum, offering exceptional chemical stability, freedom from oxidation, and compatibility with thermosonic wire bonding. These properties make gold pastes indispensable for high-reliability microelectronic circuits, hermetic packages, biomedical sensors, and aerospace-grade hybrid modules where long-term performance in aggressive environments is non-negotiable.

Our general-purpose gold paste fires at 850-980 degrees Celsius on 96% alumina and compatible high-temperature dielectric systems, producing dense, smooth layers capable of 100-micrometer line and space resolution. The fired gold film supports both aluminum and gold wire bonding with pull strengths exceeding industry reliability standards. Platinum group metal additions can be incorporated to improve solderability and leach resistance when subsequent solder attachment is required.

Gold Paste for Sensor Applications

Electrochemical sensors, biosensor platforms, and gas detection devices frequently utilize gold working electrodes for their inertness and well-defined electrochemical behavior. Our gold pastes formulated for sensor fabrication exhibit low background current, excellent adhesion to alumina and zirconia substrates, and compatibility with subsequent dielectric patterning and enzymatic functionalization steps.

Figure 3: Alumina ceramic substrate carrying parallel precious metal conductive traces

Silver-Palladium and Silver-Platinum Alloy Pastes

While pure silver offers unmatched conductivity, certain applications require enhanced solder leach resistance, migration stability, or compatibility with high-voltage environments. Silver-palladium and silver-platinum alloy pastes address these needs by combining silver's conductivity with the noble metal stability of palladium or platinum. The resulting fired films demonstrate significantly improved durability during solder attachment operations and reduced susceptibility to electrochemical migration in humid or biased conditions.

• Silver-palladium (Ag/Pd) 80:20 paste — High solder leach resistance, ideal for heater terminations and multilayer circuits subjected to repeated solder processing
• Silver-palladium (Ag/Pd) 85:15 paste — Balanced conductivity and durability, widely used for chip resistor terminations and hybrid circuit pads
• Silver-platinum (Ag/Pt) 98:2 paste — Enhanced solderability with minimal platinum addition, cost-effective upgrade from pure silver for solder-intensive assemblies
• Silver-platinum (Ag/Pt) 97:3 paste — Superior leach resistance for applications requiring extended solder bath immersion or multiple rework cycles
• Gold-platinum-palladium (Au/Pt/Pd) paste — Triple-alloy system offering exceptional solderability, wire bondability, and corrosion resistance for aerospace and medical-grade circuits

Platinum Conductive Pastes

Platinum conductor pastes deliver the ultimate in chemical and thermal stability, capable of withstanding operating temperatures up to 1000 degrees Celsius in oxidizing atmospheres. Our fritted platinum paste fires at 850-1300 degrees Celsius, forming highly conductive, dense layers on alumina and other high-temperature dielectric substrates. The exceptional catalytic activity of platinum surfaces also enables unique sensor applications including zirconia oxygen sensors, exhaust gas analyzers, and industrial process monitoring electrodes.

In addition to pure platinum conductors, our platinum pastes can be formulated with specific additives to tailor the temperature coefficient of resistance or to enhance adhesion to specialized substrates such as yttria-stabilized zirconia. These customized formulations support research programs in solid oxide fuel cells, high-temperature pressure sensors, and automotive emission control systems.

Silver Sintering Die Attach Pastes

The semiconductor packaging industry has undergone a significant materials transition as power device manufacturers move away from traditional solder die attach toward silver sintering technology. Silver sintering die attach pastes consist of micron-scale or nano-scale silver particles formulated with organic additives that enable solid-state diffusion bonding at temperatures between 180 and 300 degrees Celsius. The resulting interconnect exhibits thermal conductivity exceeding 200 W per meter-Kelvin, roughly three to five times higher than conventional solder alloys, while eliminating lead and other hazardous materials from the supply chain.

Our silver sintering pastes support both pressure-assisted and pressure-less processes, accommodating the equipment constraints and throughput requirements of various packaging lines. These materials have been qualified for silicon carbide and gallium nitride wide-bandgap semiconductor devices used in electric vehicle traction inverters, renewable energy converters, RF power amplifiers, and high-performance LED modules. The superior thermal cycling reliability of sintered silver joints — demonstrated beyond 5000 power cycles without delamination — makes these pastes the material of choice for mission-critical power electronics.

Figure 4: Semiconductor chip positioned over silver sintering die attach paste on copper leadframe

Application Areas

The precious metal pastes supplied by Eata Electronic find application across a remarkably diverse range of research disciplines and industrial sectors. Understanding these application contexts helps our customers select the optimal paste formulation for their specific device requirements.

Hybrid Microcircuits and Multilayer Systems

Thick-film hybrid circuits integrate resistors, capacitors, and conductor interconnects on ceramic substrates to create compact, high-reliability electronic modules. Our silver, gold, and alloy pastes form the conductive backbone of these systems, with dielectric pastes available for insulation layers between conductive levels. Fired at 850 degrees Celsius on alumina, these pastes produce circuits capable of operating from cryogenic temperatures to beyond 200 degrees Celsius.

Heater Elements on Ceramic and Steel

Precious metal resistor pastes — including silver-platinum and silver-palladium systems with controlled TCR values — enable precision heater fabrication on alumina, porcelain enamel steel, and dielectric-coated stainless steel substrates. These heater elements serve automotive defrost systems, laboratory heating platforms, industrial process equipment, and consumer appliance applications where uniform heat distribution and rapid thermal response are essential.

Biosensors and Medical Electronics

Screen-printed biosensors for glucose monitoring, DNA detection, and environmental pollutant analysis require electrode materials that combine electrochemical stability with biocompatibility. Our gold and silver-silver chloride pastes provide the reference and working electrodes fundamental to these analytical devices, while carbon and platinum pastes support specialized enzymatic and catalytic sensor architectures.

Photovoltaic Cell Metallization

Crystalline silicon solar cells rely on screen-printed silver paste front electrodes to collect photocurrent with minimal series resistance. Our photovoltaic-grade silver pastes contain spherical silver particles in the 1-3 micrometer size range, glass frit systems optimized for silicon nitride ARC firing-through, and organic vehicles engineered for high-speed rotary screen and inkjet printing. The resulting contacts achieve low contact resistance to heavily doped silicon while preserving high aspect ratios for reduced shadowing loss.

Precious Metal Paste Selection Guide

Figure 5: Range of precious metal pastes in laboratory containers including silver, gold, and platinum formulations

Custom Formulation and Development Services

Standard catalog formulations address the majority of thick-film and die-attach applications, yet certain research programs and production lines demand paste properties that fall outside conventional specifications. Eata Electronic maintains an active custom development capability for customers requiring tailored precious metal paste solutions.

Our formulation team can adjust particle size distribution, metal loading, glass chemistry, and organic vehicle rheology to achieve specific printability characteristics, fired film properties, or processing windows. Whether you need a silver paste with modified viscosity for inkjet deposition, a gold paste compatible with an unusual substrate composition, a silver-palladium alloy with precisely specified TCR for a precision heater application, or a die attach paste optimized for a non-standard curing profile, we can evaluate your requirements and develop a formulation that meets your technical targets.

Custom projects typically follow a structured development pathway: requirement specification, feasibility assessment, prototype formulation, customer evaluation, iterative refinement, and final qualification. Throughout this process, our materials scientists work directly with your engineering team to ensure the delivered product integrates seamlessly into your manufacturing flow.

For Research or Industrial Raw Materials, Not For Personal Medical Use!