NOVELTY - The process comprises forming a precursor layer (13) comprising coal tar and/or coal tar pitch on a substrate (11), forming a catalyst layer between the substrate and the precursor layer and/or forming a protective layer (15) on the precursor layer, and performing thermal treatment of the substrate in an inert atmosphere or vacuum at a temperature of less than 2000 degrees C for 1 second to 5 days to form a carbon thin film (17) on the substrate, where the coal tar and/or coal tar pitch are carbonized in the precursor layer during the thermal treatment.    USE - The process is useful for producing a carbon thin film, which is useful for fabricating an electronic component and an electrochemical device such as a lithium battery or a fuel cell (all claimed), where: the carbon thin film is useful as an electrode or a wiring material of the electronic component and as an active layer of a semiconductor device; the electronic component includes an inorganic LED, an organic LED, an inorganic solar cell, an organic photovoltaic diode, an inorganic thin film transistor, a storage/memory device, an electrochemical/organic sensor, a radio frequency device, a rectifier, a complementary metal oxide semiconductor device or an organic thin film transistor.    ADVANTAGE - The process ensures economic, safe and pollution free production of the carbon thin film with high electric conductivity and stability and reduced material consumption.    DETAILED DESCRIPTION - The process comprises forming a precursor layer (13) comprising coal tar and/or coal tar pitch on a substrate (11), forming a catalyst layer between the substrate and the precursor layer and/or forming a protective layer (15) on the precursor layer, performing thermal treatment of the substrate in an inert atmosphere or vacuum at a temperature of less than 2000 degrees C for 1 second to 5 days to form a carbon thin film (17) on the substrate, where the coal tar and/or coal tar pitch are carbonized in the precursor layer during the thermal treatment, and removing the remaining protective layer on the carbon thin film. The protective layer has a thickness of 2-2000 nm. The catalyst layer has a thickness of 100-1000 nm. The method further comprises forming a predetermined pattern on the precursor layer and the catalyst layer and/or the protective layer prior to the thermal treatment step, and/or forming a predetermined pattern on the carbon thin film after the thermal treatment step. The carbon thin film includes a graphite layer, a graphene layer and an amorphous carbon layer. The substrate is a metal substrate or a polymer substrate. INDEPENDENT CLAIMS are included for:    (1) an electronic component; and    (2) an electrochemical device comprising a carbon thin film.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional view of a method for producing a carbon thin film.    Substrate (11)    Precursor layer (13)    Protective layer (15)    Carbon thin film. (17)