The interest in laser-induced chemical deposition of metal from solution (LCLD) stems from the prospects of its use in microelectronics due to the ability to create extended localized metal structures 5-100 mkm wide on dielectric surfaces. Scanning a dielectric surface with a focused laser beam in an electrolyte solution leads to locally initiated chemical reduction of copper. Composition of plating solution is organic complexing agent, usually sodium potassium tartrate or EDTA and reducing agent, copper salt and alkali. The spot of locally initiated reaction can be moved along substrate using computer-controlled motorized translation stage. LCLD is known to be a perspective method for manufacturing of metal interconnections for printed and flexible electronic devices. It is maskless technology, promising cost-effective environmentally friendly manufacturing process for prototyping and small-scale production of high precision PCBs and electrochemical sensors. An unsolved technical problem that prevents the practical application of LCLD is intense gas evolution occurring around the laser beam focus point on the dielectric surface. The formation of gas bubbles in the laser beam path leads to its defocusing. As a result, metal deposition from solution is uncontrollably discontinued, or it occurs in a refracted or reflected irradiation zone. In such a case, diffuse edges, areas with unsatisfactory topology, ruptures, tails of the metal deposited in a non-localized way, and other flaws are formed on the metal deposited structure. In order to solve the problem of gas evolution in direct copper deposition process our group has developed a number of metallization solutions, containing nonionic surfactants. The scanning speed of laser beam was 0.01-01mm/s, DPSS laser (532nm) working in continuous mode was used for irradiat ion of samples, power of laser beam was 200-1000mW, diameter of focal spot was 10-50 mkm). These series of experiments were performed with oxide glass and glass-ceramics material «Sitall» consisting of Al2O3 and SiO2. The effect of non-ionic surfactants on the structure of copper deposits was observed. Using of the surfactants with lower HLB but still soluble in water help lead to formation of electrical conductive copper microwires with narrow structure.

Laser-induced copper deposition from solution with the addition of non-ionic surfactants: Influence of hydrophilic properties

249th National Meeting (2015)

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