Put your engineering intuition to work.

Copper can be electroplated from an aqueous solution. Cobalt is below hydrogen in the electrochemical series, yet cobalt can also be electroplated from water. How is that possible?

An etch-stop film protects the lower copper line during via etching, but its job does not end when fabrication is complete.

A working chip contains billions of transistors and many layers of metal interconnections. When the chip becomes hot, where is the heat actually generated?

Titanium oxide has a higher dielectric permittivity than tantalum oxide. So why are porous electrolytic capacitors made from tantalum rather than titanium?

A digital inverter performs the simplest possible logic operation: it changes 1 into 0 and 0 into 1. So why does it need two transistors?

The back end of line (BEOL) connects the transistors formed in the chip’s front end of line (FEOL). The interconnect lines are built within an interlayer dielectric (ILD), typically based on silicon oxide. Copper is widely used for these interconnects because of its excellent electrical conductivity.

The light source is unchanged. The reticle is unchanged. The projection lens is unchanged. Only air is replaced with water, yet smaller features can be printed.