摘要 |
A negative-working imaging composition suitable for use as a dry film resist, comprises, in admixture, (a) a polymeric binder, (b) a Co (III) compound capable of partial reduction to Co (II) upon exposure to activating radiation, and (c) a redox transfer ligand capable of reacting with Co (II) to form a Co (II) chelate which reduces adjacent remaining Co (III) compound and forms a Co (III) chelate effective to provide imagewise differential solubility to the composition. The composition can be imagewise exposed to activating radiation, such as a laser, heated, and developed with a developer to form a resist image in the exposed areas. An element comprising a support and a layer of the above-described composition is particularly useful in the manufacture of printed circuit boards by laser direct imaging.
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