Patterning directly on an amorphous silicon hardmask
The invention herein includes enhancing the surface of an amorphous silicon hardmask through implantation of nonpolar, hydrophobic elements, resulting in increased hydrophobicity and increased resist adhesion of the amorphous silicon surface. According to the invention, implanting the hydrophobic elements may involve introduction of the hydrophobic elements into the surface of the amorphous silicon by way of low energy implantation and plasma treatment. The implanted hydrophobic element may be Boron, Xenon, Fluorine, Phosphorus, a combination thereof, or other hydrophobic elements. According to the invention, the surface of the amorphous silicon is enhanced with 10-15% hydrophobic element, however in other embodiments, this composition may be adjusted as needed. In any case, however, the invention herein includes maintaining an etch selectivity of the bulk amorphous silicon hardmask.
1. A structure comprising:
an amorphous silicon hardmask layer having an upper surface and a bulk material, wherein a composition of the upper surface includes one or more hydrophobic elements, wherein the upper surface is defined by an implantation thickness achieved via a low energy implantation, wherein the upper surface and the bulk material have different chemical compositions; and
a photoresist layer directly on the upper surface of the amorphous silicon hardmask layer, wherein the photoresist layer comprises a plurality of structures, and wherein the plurality of structures have a pitch less than 50 nm between each of the plurality of the structures.
2. The structure of claim 1 , wherein the upper surface composition of the amorphous silicon hardmask layer includes 10-15% of the one or more hydrophobic elements.
3. The structure of claim 2 , wherein a contact angle between the upper surface and the photoresist layer comprises and angle of 45 to 52 degrees.
4. The structure of claim 1 , wherein the one or more hydrophobic elements include at least one element selected from a group comprising boron, xenon, fluorine, and phosphorus.
5. The structure of claim 1 , wherein the amorphous silicon hardmask layer maintains an etch selectivity consistent with amorphous silicon.
6. The structure of claim 1 , wherein the upper surface of the amorphous silicon hardmask maintains a same bulk etch selectivity as the bulk material.