Photochemical Selective Activation for Electroless Metal Deposition on Nonconductors

Abstract

The photochemical methods for selective activation of nonconductors for electroless metal deposition have been classified in this review on the basis of kinetic scheme involved. There are three general kinetic schemes for the formation of catalytic metallic nuclei on nonconductors: photoelectrochemical, photoelectron, and intramolecular photoreduction. Photoelectrochemical scheme involves a photochemical reaction which is followed by an electrochemical reaction. The photochemical reaction is used to produce or deactivate the reducing agent. Catalytic metallic nuclei are formed in the subsequent electrochemical reaction. In the photoelectron method, electrons necessary for the formation of catalytic metallic nuclei M from metallic cations M+n are generated in the direct absorption process of a photon by a semiconductor crystal, which results in the generation of an electron and a hole. In the intramolecular photoreduction kinetic scheme catalytic metallic nuclei are formed in the intramolecular ligand to metal electron transfer process. This review surveys fundamental photochemical principles and discusses problems and prospects of the above processes.

Interactions of Electroless Catalysts with Plasma‐Oxidized Surfaces of Polystyrene‐Based Resins

“…There are a number of techniques that use electroless deposition for applying metal patterns onto polymeric substrates (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11). Sharp (1), Chow et al (5), Schlesinger et al (6,7), and Baylis et al (8)(9)(10)(11) examined methods by which the electroless catalysts were photochemically activated (9) or deactivated (5).…”

“…For instance, chemical groups that poison electroless catalysts can be incorporated in the substrate (2,3) or synthesized by photo-oxidation of some surfaces containing polystyrene (reactions [1]- [3] (12)(13)(14)). The poisoning effect of the photo-oxidation process can be reversed by soaking the photo-oxidized polymers in an alkaline solution before catalysis (reaction [4]). X-ray photoelectron spectroscopy (XPS) measurements indicate that the catalysts are poisoned by photochemically produced surface carbonyls (probably carboxylates) which are cleaved by the alkaline soak (12) sub + cat ~ sub-cat (platable) [1] hy sub + 02 --> sub ~ (photo-oxidized) [2] sub s + cat ---> subs~-cat (unplatable) [3] sub ~ + OH----> sub (platable) cat = electroless catalyst sub = PS, SAN, or ABS substrate (unmodified) sub ~ = photo-oxidized substrate [4] The interaction between a photo-oxidized surface and the electroless catalyst seems to be fairly general for Pdbased catalysts.…”

“…The poisoning effect of the photo-oxidation process can be reversed by soaking the photo-oxidized polymers in an alkaline solution before catalysis (reaction [4]). X-ray photoelectron spectroscopy (XPS) measurements indicate that the catalysts are poisoned by photochemically produced surface carbonyls (probably carboxylates) which are cleaved by the alkaline soak (12) sub + cat ~ sub-cat (platable) [1] hy sub + 02 --> sub ~ (photo-oxidized) [2] sub s + cat ---> subs~-cat (unplatable) [3] sub ~ + OH----> sub (platable) cat = electroless catalyst sub = PS, SAN, or ABS substrate (unmodified) sub ~ = photo-oxidized substrate [4] The interaction between a photo-oxidized surface and the electroless catalyst seems to be fairly general for Pdbased catalysts. For instance, irradiation produces surfaces which deactivate (12) a two-step catalyst, produced by sequential exposure of the substrate first to SnC12 and then to PdC12 solutions, and a colloid catalyst (15).…”

Electroless Deposition of Copper

“…where Ox is the oxidation product of acetate ion, Ac [78]. Other photochemical methods were, for instance, reviewed by Paunovic [78].…”

Selective deposition on electrodes of chip component by electroless plating method

“…[1][2][3] Basically, before electroless plating, surface pretreatments such as surface sensitization and activation are required. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] In general, there are two methods used for surface sensitization and activation, that is, the "two-step" process and "one-step" process. In the traditional two-step process, the substrate is immersed successively in acidic SnCl 2 solution and acidic PdCl 2 solution.…”