Through-wafer vias

A structure, comprising:

• (a) a wafer which includes a top wafer surface,
• wherein the top wafer surface defines a first direction perpendicular to the top wafer surface;
• and
• (b) M composite through-wafer via structures,
• wherein M is an integer greater than one,
• wherein the M composite through-wafer via structures are arranged in an array of C columns and R rows such that C is at least 1 and R is at least 1,
• wherein for i=1, . . . , M, an ith composite through-wafer via structure of the M composite through-wafer via structures comprises Ni through-wafer vias in the wafer, each through-wafer via of the Ni through-wafer vias having a shape of a rectangular plate,
• wherein Ni is an integer greater than one,
• wherein the Ni through-wafer vias are parallel to one another,
• wherein in the ith composite through-wafer via structure, a height of each through-wafer via of the Ni through-wafer vias in the first direction is equal to a thickness of the wafer in the first direction,
• wherein the first direction, a second direction, and a third direction are fixed directions that are mutually perpendicular to each other, and
• wherein the N1 through-wafer vias of the first composite through-wafer via structure are spaced apart from each other in the second direction, and
• wherein the N2 through-wafer vias of the second composite through-wafer via structure are spaced apart from each other in the third direction.

A structure, comprising:

• (a) a wafer which includes (i) an opening and (ii) a top wafer surface,
• wherein the top wafer surface defines a first reference direction perpendicular to the top wafer surface;
• and
• (b) a trench filled with a filling material,
• wherein the filling material extends from side walls of the trench and converges onto a convergence surface,
• wherein a plane perpendicular to the first reference direction intersects the convergence surface through a convergence curve,
• wherein the convergence curve does not comprise a closed loop,
• wherein a height of the trench in the first reference direction essentially equals a thickness of the wafer in the first reference direction,
• wherein a length of the convergence curve is at least twenty times greater than a convergence distance by which the filling material grows from the side walls of the trench to the convergence surface, and
• wherein said height of the trench is at least 20 times the convergence distance.