From bare wafer to device layers
Wafer fabrication starts with cleaning and planarization. Materials are deposited by PVD, CVD, ALD, epitaxy, and related methods. Lithography defines patterns, etching transfers those patterns into films, and ion implantation plus annealing modifies local doping for wells, source/drain regions, and threshold-voltage tuning.
Why the loop repeats
A chip is a multilayer 3D object, not a flat drawing. Transistors, contacts, local interconnect, global metal layers, and passivation all require repeated deposition, lithography, etching, cleaning, and metrology. The challenge is not one perfect step; it is keeping line width, overlay, defect density, and electrical behavior controlled across hundreds of steps.
Why GPUs care
GPU dies are large and transistor-rich, making them sensitive to uniformity and defect control. A film thickness shift, etch residue, or particle contamination can hurt yield on large dies. As flows become more complex, process control, inline metrology, and statistical process control become central to product success.