Stepper

A stepper is a device used in the manufacture of integrated circuits (ICs) that is similar in operation to a slide projector or a photographic enlarger. Steppers are an essential part of the complex process, called photolithography, that creates millions of microscopic circuit elements on the surface of tiny chips of silicon. These chips form the heart of ICs such as computer processors, memory chips, and many other devices.

The stepper's role in photolithography

Elements of the circuit to be created on the IC are reproduced in a pattern of transparent and opaque areas on the surface of a quartz plate called a photomask or reticle. The stepper passes light through the reticle, forming an image of the reticle pattern. The image is focused and reduced by a lens, and projected onto the surface of a silicon wafer that is coated with a photosensitive material called photoresist.

After exposure in the stepper, the coated wafer is developed like photographic film, causing the photoresist to dissolve in certain areas according to the amount of light the areas received during exposure. These areas of photoresist and no photoresist reproduce the pattern on the reticle. The developed wafer is then exposed to acids or other chemicals. The acid etches away the silicon in the parts of the wafer that are no longer protected by the photoresist coating. The other chemicals are used to change the electrical characteristics of the silicon in the bare areas. The wafer is then cleaned, recoated with photoresist, then passed through the stepper again in a process that creates the circuit on the silicon, layer by layer. The entire process is called photolithography or photo engineering.

One drop rhythm

The One drop was popularized by Carlton Barrett, long-time drummer of Bob Marley and the Wailers.

The original creator of the pattern is often disputed, and many reggae drummers have taken credit.

One drop rhythm is a drumset playing style of reggae.

Characteristics

The backbeat is characterized by the dominant snare drum stroke (usually a click produced by cross-sticking) and bass drum both sounding on the third beat of every four, while beat one is left empty. Thus, the expected hit on beat one is "dropped," creating the one-drop effect. Dropping out the bass on the "one" of the measure further accentuates the downbeat of the drums creating the rhythm.

This may be seen in the drum notation for the typical rock drum pattern:

and the one drop:

Variations

The rockers rhythm is essentially the one drop with a steady bass drum on every eighth note, though one drop is slower than a ska pattern, and rockers is often slower than one drop.

The steppers rhythm is essentially the one drop with a steady bass drum on every quarter note.

Stepper (disambiguation)

A stepper is a device used in the manufacture of integrated circuits.

Stepper may also refer to: