Methods of forming through silicon via openings

1. A method, comprising:

forming an opening in a substrate, the opening completely extending through the substrate, wherein a recast material is formed on sidewalls of the substrate exposed by the opening;

applying a first chemical in the opening to remove the recast material, wherein a residue of the first chemical remains on portions of the sidewalls after the applying of the first chemical; and

applying a second chemical in the opening to remove the residue of the first chemical, wherein the second chemical is different from the first chemical, wherein the second chemical contains a first component being substantially inactive with the substrate and a second component being substantially active with the material of the first chemical, wherein the first component is selected from the group consisting of helium, neon, argon, krypton, xenon, and radon, and the second component comprises hydride.

2. The method of claim 1 , wherein the forming of the opening comprises laser drilling the opening through the substrate.

3. The method of claim 2 , wherein the substrate contains silicon, and the recast material is formed by melting the silicon through the laser drilling and cooling the melted silicon.

4. The method of claim 1 , wherein the sidewalls of opening is formed in a manner such that they are roughened or have an hourglass shape.

5. The method of claim 1 , wherein the first chemical contains a material that activates the recast material.

6. The method of claim 5 , wherein the material of the first chemical includes halogen.

7. The method of claim 1 , wherein the forming of the opening and the applying of the first chemical are performed simultaneously.

8. The method of claim 1 , further comprising forming a water-soluble layer over the substrate before the forming of the opening and removing the water-soluble layer with deionized water after the forming of the opening.

9. The method of claim 1 , further comprising forming a conductive structure in the opening after the applying of the second chemical.

10. A method, comprising:

providing a substrate having a first side and a second side opposite the first side;

performing a laser ablating process to form an opening that extends from the first side of the substrate to the second side of the substrate, wherein the laser ablation process melts portions of the substrate, thereby leaving a recast material in the opening;

removing the recast material with a first chemical, wherein the removing of the recast material leaves a residue of the first chemical in the opening; and

removing the residue of the first chemical with a second chemical different from the first chemical, wherein the first chemical contains halogen and the second chemical contains a first component being substantially inactive with the substrate and a second component being substantially active with halogen, wherein the first component is selected from the group consisting of helium, neon, argon, krypton, xenon, and radon, and the second component comprises hydride.

11. The method of claim 10 , wherein the removing of the recast material is performed while the laser ablation process is being performed.

12. The method of claim 10 , wherein the opening is formed such that the recast material contributes to an hourglass shape of the opening.

13. The method of claim 10 , further comprising forming a water-soluble layer over the substrate before the performing of the laser ablation process and removing the water-soluble layer with deionized water after the performing of the laser ablation process.

14. The method of claim 10 , further comprising forming a through-silicon-via in the opening after the removing of the residue.

15. A method, comprising:

forming a through-silicon-via (TSV) opening in a silicon substrate through a laser process that melts the silicon of the silicon substrate, wherein the melted silicon adheres to a sidewall of the TSV opening after being cooled, thereby giving the TSV opening at least one of: an hourglass shape and roughened sidewall surfaces;

removing the melted silicon using a halogen-containing first chemical, wherein the halogen-containing first chemical leaves a residue in the TSV opening;

removing the residue of the halogen-containing first chemical with a second chemical, the second chemical containing a first component that is substantially inactive with the silicon substrate; and

a second component that is substantially active with halogen; and

thereafter forming a conductive material in the TSV opening, wherein the first component is selected from the group consisting of helium, neon, argon, krypton, xenon, and radon, and the second component comprises hydride.