Process for thin film formation by sputtering
First Claim
1. A process for forming a thin film having refractive index thereof varying continuously or stepwise in a thickness direction, comprising sputtering by introducing, during film formation, a nitrogen-containing gas, an oxygen-containing gas, and a fluorine-containing gas with a flow rate ratio of the fluorine-containing gas to the nitrogen-containing gas and/or the oxygen-containing gas varied continuously or stepwise.
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Abstract
A process is provided for forming a thin film having refractive index thereof varying continuously or stepwise in a thickness direction. The process comprises sputtering in a vacuum chamber by introducing, during film formation, at least two kinds of gases selected from a nitrogen-containing gas, an oxygen-containing gas, and a fluorine-containing gas with the flow rate ratio of the gases varied continuously or stepwise. This process enables variation of the refractive index in the thickness direction, simply without difficulty.
22 Citations
17 Claims
- 1. A process for forming a thin film having refractive index thereof varying continuously or stepwise in a thickness direction, comprising sputtering by introducing, during film formation, a nitrogen-containing gas, an oxygen-containing gas, and a fluorine-containing gas with a flow rate ratio of the fluorine-containing gas to the nitrogen-containing gas and/or the oxygen-containing gas varied continuously or stepwise.
- 2. A process for forming a thin film having refractive index thereof varying continuously or stepwise in a thickness direction, comprising sputtering by introducing, during film formation, at least a nitrogen-containing gas and a fluorine-containing gas with a flow rate ratio of the nitrogen-containing gas to the fluorine-containing gas varied continuously or stepwise.
- 3. A process for forming a thin film having refractive index thereof varying continuously or stepwise in a thickness direction, comprising sputtering by introducing, during film formation, at least an oxygen-containing gas and a fluorine-containing gas with a flow rate ratio of the oxygen-containing gas to the fluorine-containing gas varied continuously or stepwise.
- 16. A process for forming a thin film by sputtering, comprising forming a first thin film having a first refractive index and thereafter forming a second thin film having a second refractive index different from the first refractive index, wherein the sputtering is conducted by introducing, during film formation, at least two gases, one of which is a fluorine-containing gas and the other gas or gases are a nitrogen-containing gas and/or an oxygen-containing gas, with a flow rate ratio of the fluorine-containing gas to the nitrogen-containing gas and/or the oxygen-containing gas varied continuously or stepwise to obtain a refractive index varying continuously or stepwise in a thickness direction in the neighbourhood of the boundary between the first thin film and the second thin film.
Specification