Roughness evaluation method and system

A lithography method comprising:

• a resist pattern forming step of coating a resist film on a substrate, exposing it through a mask and developing it;
• an etching step of removing a part of the substrate that is not covered with the resist film by etching;
• a roughness evaluating step of evaluating a roughness of the resist after the resist pattern forming step or evaluating roughness of a circuit pattern after the etching step;
• and
• a processing condition changing step of changing processing conditions of the resist pattern forming step or the etching step based on the roughness evaluated in the roughness evaluating step, wherein
• the roughness evaluating step includes:
• a measuring step of irradiating light onto a plurality of locations of the substrate and measuring a state of reflected light by a scatterometry method;
• an analyzing step of evaluating a roughness of one or more lines based on a variation in values measured in the measuring step;
• and
• a sample measuring step of irradiating light onto a plurality of locations of a reference sample to measure a state of reflected light by the scatterometry method, wherein,
• in the analyzing step, the variation in the values measured in the measuring step is compared to a variation in values of the reference sample measured in the sample measuring step to calculate an index based on a difference between the variation in the values measured in the measuring step and the variation in the values of the reference sample measured in the sample measuring step, and wherein,
• if the index is larger than a specific value, then a roughness is evaluated to exist.

A roughness evaluation system for evaluating a roughness of one or more lines formed on a substrate, the system comprising:

• an optical device which irradiates light onto a reference sample and the substrate, and measures states of reflected light from the reference sample and the substrate by a scatterometry method;
• a moving device which moves the substrate in at least one of an x-direction and a y-direction on a horizontal plane;
• a controller which controls the moving device such that the optical device measures a plurality of locations on the substrate;
• and
• an analysis unit which evaluates the roughness based on a variation in values measured at the plurality of locations on the substrate, wherein
• the analysis unit compares the variation in the values measured at the plurality of the locations on the substrate to a variation in values measured from the reference sample to calculate an index based on a difference between the variation in the values measured at the plurality of the locations on the substrate and the values of the reference sample, and wherein,
• if the index is larger than a specific value, the analysis unit evaluates that there is a roughness.

A lithography system comprising:

• a resist pattern forming system which coats a resist film on a substrate, exposing it through a mask and developing it;
• an etching system which removes a part of the substrate that is not covered with the resist film by etching;
• and
• a roughness evaluation system which evaluates a roughness of a resist on the substrate or a circuit pattern on the substrate, wherein
• processing conditions of the resist pattern forming system or the etching system are changed based on the roughness evaluated by the roughness evaluation system, and wherein
• the roughness evaluation system includes:
• an optical device which irradiates light onto a reference sample and the substrate, and measures states of reflected light from the reference sample and the substrate by a scatterometry method;
• a moving device which moves the substrate in at least one of an x-direction and a y-direction on a horizontal plane;
• a controller which controls the moving device such that the optical device measures a plurality of locations on the substrate;
• and
• an analysis unit which evaluates the roughness based on a variation in values measured at the plurality of locations on the substrate, wherein
• the analysis unit compares the variation in the values measured at the plurality of the locations on the substrate to a variation in values measured from the reference sample to calculate an index based on a difference between the variation in the values measured at the plurality of the locations on the substrate and the values of the reference sample, and wherein,
• if the index is larger than a specific value, the analysis unit evaluates that there is a roughness.