The greenhouse gas (GHG) emissions of semiconductor manufacturing represent an important share of the embodied carbon footprint of electronics systems. Manufacturing emissions are disclosed in the sustainability reports of semiconductor companies. This paper proposes a study of global semiconductor manufacturing carbon emissions, focusing on Scope 1 (direct emissions) and Scope 2 (emissions induced by consuming energy). The fifteen companies on the semiconductor market with highest 2021 revenues are considered, as well as the four main merchant foundries, over the years 2020 and 2021. As a large scale evaluation of carbon impacts, the resulting numbers compile heterogeneous figures and require a comprehensive discussion on the strengths and limitations of the evaluation. Most of the efforts on this paper are thus allocated to this discussion. The 2021 carbon emissions for the semiconductor industry worldwide are estimated at 76.5M tons of CO2 equivalent, breaking down into 30.6M tons CO2e of Scope 1 emissions (direct emissions), and 45.9M tons CO2e of scope 2 emissions (emissions induced by the energy consumption of manufacturing). These numbers do not include the Scope 3 impacts, neither downwards (usage of the products) nor upwards (constructing fabrication facilities, building fabrication machines, extracting raw materials, smelting and refining materials). Between 2020 and 2021, Scope 1&2 emissions of semiconductor manufacturing have increased by 13%.