Exposure apparatus and device manufacturing method

A method comprising:

• exposing a substrate using an exposure apparatus;
• and
• developing the exposed substrate,
• wherein the exposure apparatus is configured to perform, using light supplied from a light source, an exposure process of transferring a pattern of an original onto a substrate by exposure and a measurement process for alignment between the original and the substrate, and comprises:
• a controller configured to control the light source,
• wherein the light source has an oscillation frequency that varies and is a number of times of light emission per unit time, and includes a control system configured to control a spectrum width of the light, and
• the controller oscillates the light source at a first oscillation frequency by setting the control system to an inactive state in the measurement process, and oscillates the light source at a second oscillation frequency by setting the control system to an active state in the exposure process.

A method comprising:

• performing an exposure process and a measurement process using light supplied from a light source having an oscillation frequency that varies and is a number of times of light emission per unit time;
• controlling the light source by a controller;
• controlling a spectrum width of the light by a control system;
• oscillating the light source at a first oscillation frequency by setting the control system to an inactive state in the measurement process;
• and
• oscillating the light source at a second oscillation frequency by setting the control system to an active state in the exposure process.