How to build a lithography machine at home? Let’s first look at the final result: inside the small rectangular frame next to the corn kernel, an entire page of densely packed text has been engraved. How is this lithographic process achieved? Keep reading to find out. First, clean the glass substrate with isopropyl alcohol and bake it on a 250°C hotplate for three minutes. Then proceed with spin-coating the photoresist. It is recommended to use S Lear 003 negative photoresist, spinning at 3,000 rpm for 30 seconds to form a uniform thin film 1–2 micrometers thick. Next comes UV exposure. First, DIY a 365-nanometer UV exposure setup. Place a transparent film printed with text above the light source to serve as a photomask, projecting the text onto the substrate. Exposure time depends on light intensity, typically ranging from 10 to 300 seconds. Then begin development. This step usually employs S300F developer solution, agitating for 20 to 50 seconds. Since a negative photoresist is used, the unexposed areas—those shielded by the text—are dissolved, while the rest of the photoresist remains intact. Next, place the substrate into a metal vacuum deposition chamber and sputter a layer of titanium metal onto it using a magnetron, achieving a thickness of approximately 100–300 nanometers. Finally, immerse the substrate in acetone to dissolve the photoresist surrounding the text. The titanium metal adhering to the photoresist is removed along with it. After drying with nitrogen gas, clear titanium text can be observed under a microscope. This completes the simplified lithography process. Lithography is one of the most core processes in modern microelectronics manufacturing, used to print extremely tiny circuit patterns on wafers. Nearly all chips rely on lithography, and a country’s lithographic capabilities determine the upper limit of its semiconductor manufacturing prowess.