Equation 1 · Part 6 · Patterning at the Limit: What Actually Happens When a Chip Is Manufactured

subscript

R = k_1 \frac{\lambda}{\mathrm{NA}},

subscript

What this part means

The lower label selects a particular version, component, or indexed member of the quantity. For example, x₀ and xₜ can be values at different positions.

Its job in the formula

A subscript distinguishes a version, component, step, or member of a quantity. It does not automatically mean multiplication.

Full expressionsubscriptArticle meaning

The passage around this formula

Only one step in the loop carries information, so it deserves the arithmetic. Projection lithography is an imaging problem, and its resolution obeys the Rayleigh relation $R = k_1 \frac{\lambda}{\mathrm{NA}}$ . where $\lambda$ is the exposure wavelength, $\mathrm{NA}$ is the numerical aperture of the projection optics, and $k_1$ is a dimensionless process factor absorbing illumination scheme, mask engineering and resist behaviour. Two-beam interference sets a hard floor: for a periodic line-and-space pattern the smallest printable half-pitch is $\lambda$ / (2\, $\mathrm{NA}$ ) , which is $k_1$ = 0.25 in the convention where R is a half-pitch. Everything the industry calls resolution enhancement — off-axis illumination,…

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Learn the underlying idea

A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.

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Sources cited in the article section

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