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AssigneeSiemens Aktiengesellschaft
InventorsWilly Beinvogl, Barbara Hasler
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Polysilicon structures down to a 1 .mu.m range on substrates containing integrated semiconductor circuits are produced by plasma etching in a plate reactor with the use of SF.sub.6 and an inert gas as the reactive gas. During this process, a semiconductor crystal wafers (4, 17) covered with a SiO.sub.2 layer (16) and a polysilicon layer (15) is provided with an etch mask (14) and positioned on a grounded electrode of the plate reactor and an etching process, which achieves a high selectivity of polysilicon (15) to SiO.sub.2 (16) and to the etch mask (14), is carried out with a HF power, P, of <0.1 watt/cm.sup.2, a gas pressure, p, ranging from 60 to 120 Pa, and an electrode temperature ranging from 20.degree. to 60.degree. C. With the inventive process, large scale integrated semiconductor circuits are produced in a single stage sequence with high etching selectivity, uniform etching and a high throughput of silicon wafers.
In a method of producing polysilicon structures down to a 1 .mu.m range on substrates containing integrated semiconductor circuits by plasma etching in a plate reactor with a reactive gas mixture composed of SF.sub.6 and an inert gas wherein a substrate to be etched is provided with a 3-layered structure defined by a layer of silicon dioxide positioned directly on said substrate, a layer of polysilicon positioned on said silicon dioxide layer and a resist mask positioned on said polysilicon layer, and said substrate is positioned on a grounded electrode, the improvement comprising:
Dependencies are inferred from the claim text.