System and method for extreme ultraviolet source control

An extreme ultraviolet (EUV) lithography system, comprising:

• a radiation source, wherein the radiation source includes:
• a target droplet generator configured to generate target droplets;
• a first laser source configured to generate first laser pulses that heat the target droplets to produce target plumes;
• a second laser source configured to generate second laser pulses that heat the target plumes to produce plasma emitting EUV radiation;
• third and fourth laser sources configured to generate first and second laser beams, respectively, that are directed onto a travel path of the target plumes, wherein the first and second laser beams are parallel;
• a monitor configured to receive the first and second laser beams reflected by the target plumes;
• and
• a collector configured to collect and reflect the EUV radiation;
• a mask stage configured to secure an EUV mask;
• a wafer stage configured to secure a semiconductor wafer;
• and
• one or more optical modules configured to direct the EUV radiation from the radiation source to image an integrated circuit (IC) pattern defined on the EUV mask onto the semiconductor wafer.

A method for extreme ultraviolet (EUV) lithography, the method comprising:

• generating a target droplet;
• producing a target plume by heating the target droplet with a first laser pulse generated by a first laser source;
• directing first and second laser beams onto a travel path of the target plume, wherein the first and second laser beams are parallel;
• receiving the first and second laser beams reflected by the target plume;
• and
• producing EUV-radiating plasma by heating the target plume with a second laser pulse generated by a second laser source.