Atomic layer etching (ALE) is an emerging technique in semiconductor manufacture, in which a sequence alternating between self-limiting chemical modification steps which affect only the top atomic layers of the wafer, and etching steps which remove only the chemically-modified areas, allows the removal of individual atomic layers. The standard example is etching of silicon by alternating reaction with

chlorine Chlorine is a chemical element; it has Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between ...

and etching with

argon Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abu ...

ions. This is a better-controlled process than

reactive ion etching Reactive-ion etching (RIE) is an etching technology used in microfabrication. RIE is a type of dry etching which has different characteristics than wet etching. RIE uses chemically reactive plasma to remove material deposited on wafers. The ...

, though the issue with commercial use of it has been throughput; sophisticated gas handling is required, and removal rates of one atomic layer per second are around the state of the art. The equivalent process for depositing material is

atomic layer deposition Atomic layer deposition (ALD) is a thin-film deposition technique based on the sequential use of a gas-phase chemical process; it is a subclass of chemical vapour deposition. The majority of ALD reactions use two chemicals called wiktionary:precu ...

(ALD). ALD is substantially more mature, having been used by

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, and Delaware General Corporation Law, incorporated in Delaware. Intel designs, manufactures, and sells computer compo ...

for

high-κ dielectric In the semiconductor industry, the term high-κ dielectric refers to a material with a high dielectric constant (κ, kappa), as compared to silicon dioxide. High-κ dielectrics are used in semiconductor manufacturing processes where they are usual ...

layers since 2007 and in Finland in the fabrication of thin film electroluminescent devices since 1985.

References

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External links

ECS-JSS focus journal on atomic layer etchOverview of atomic layer etching in the semiconductor industry
Industrial processes Chemical processes Semiconductor device fabrication Etching (microfabrication)