OSP reaction mechanismOSP reaction mechanismOrganic film is formed by azole compound in OSP material.

WPF106A and WPF15 have benz-imidazole ,KESTER has imidazole and triazole

Reaction mechanism»

azole compounds adsorption

on exposed copper surface

NH

N

R

NH

N

R

NH

N

N

benz-imidazole imidazole triazole

*note: R means branched chain, and is different between each OSP materials

copper land

NH NH NH

N

R

N

R

N

R

(2) Hydrogen(proton) elimination

and dehydration

copper land

N-

N

R

Cu+N-

N

R

Cu+N-

N

R

Cu+

+ H2O

OSP reaction mechanismOSP reaction mechanism

chelate formation

copper land

N-

R

Cu+

N:

N-

R

Cu+

N:

N-

R

Cu+

N:

copper land

N

R

Cu+

N:

N

R

Cu+

N:

N

R

Cu+

N:

N

R

Cu++

N:

N

R

N:

N

R

N:

Cu++ Cu++

(4) Organic film formation

Copper chelate is formed by Cu2+ in OSP material or Copper surface on PWB

KESTER has no Cu2+