Systems and methods for electroless plating of thin gold films directly onto silicon nitride and into pores in silicon nitride
A method is disclosed for electroless plating of thin metal film directly onto a substrate. The method includes the steps of: cleaning the substrate to remove organic material; etching a surface of the substrate to remove an oxygen-containing surface layer; soaking and rinsing the substrate in a plurality of baths following etching; and electroless plating the metal onto the substrate.
1. A method of plating a thin metal film directly onto a substrate comprising silicon nitride or silicon, said method comprising the steps of:
cleaning the substrate to remove organic material;
etching a surface of the substrate with an etchant to remove an oxygen-containing surface layer to expose an underlying surface of silicon nitride or silicon for direct plating thereupon;
soaking the substrate in at least one bath comprising metal ions following etching to sensitize the exposed surface for plating; and
electroless-plating of a precious metal film directly onto the exposed surface of silicon nitride or silicon without any intervening layer in between by bringing into contact said sensitized and exposed surface with a solution containing said precious metal.
2. The method of claim 1 , wherein the substrate comprises silicon-rich silicon nitride.
3. The method of claim 1 , wherein the etchant is hydrofluoric acid.
4. The method of claim 1 , wherein the method further comprises the step of patterning the substrate surface with an organic overlayer by using a spatially selective hydrosilylation reaction.
5. The method of claim 4 , wherein the step of patterning the surface with an organic overlayer comprises photochemically attaching the overlayer through initially providing contact between an 1-alkene or 1-alkyne-terminal of the overlayer and the substrate surface.
6. The method of claim 1 , wherein the precious metal is gold.
7. The method of claim 1 , wherein the method comprises a step of sensitizing the substrate surface with a solution containing tin (Sn) ions before the electroless plating step.
8. The method of claim 1 , further comprising electrolessly plating an interior wall in the substrate defining a space obscured by line-of-sight.
9. A method of plating a thin gold film directly onto a substrate comprising silicon nitride or silicon, said method comprising the steps of:
cleaning the substrate to remove organic material with plasma;
etching the surface of the substrate with an etchant to remove an oxygen-containing surface layer to expose an underlying surface of silicon nitride or silicon for direct plating thereupon;
patterning the surface with an organic overlayer by using a spatially selective hydrosilylation reaction;
soaking the substrate using at least one bath comprising metal ions following etching to sensitize the exposed surface for plating; and
electroless-plating gold directly onto the exposed surface of silicon nitride or silicon without any intervening layer in between by bringing into contact said sensitized and exposed surface with a gold-containing solution.
10. The method of claim 9 , wherein the substrate comprises silicon-rich silicon nitride.
11. The method of claim 9 , wherein the etchant is hydrofluoric acid.
12. The method of claim 9 , wherein the method comprises a step of sensitizing the substrate surface with a solution containing palladium (Pd) ions before the electroless plating step.
13. The method of claim 9 , further comprising electrolessly plating an interior wall in the substrate defining a space obscured by line-of-sight.