Overlay measurement device and method, and system and program therefor

An overlay measurement system, comprising:

• a user terminal generating data that comprise information on a recipe which is input through a manager program, and unique information on an overlay measurement device, and transmitting the generated data to an overlay measurement device corresponding to the unique information, and
• the overlay measurement device analyzing a recipe included in the data that are received from the user terminal, and performing optimization of measurement options of a wafer, based on the recipe, after the recipe is analyzed,
• wherein the overlay measurement device measures an error between a first overlay mark and a second overlay mark respectively formed on different layers of a wafer,
• wherein the overlay measurement device comprises a light source, an objective lens that concentrates a beam from the light source on a measurement position of the wafer and gathers the beam being reflected in the measurement positon, a lens focus actuator that adjusts a distance between the objective lens and the wafer such that a focus surface is placed at the first overlay mark or the second overlay mark, an auto focus module that adjusts a focus by adjusting the lens focus actuator, and a detector for obtaining an image of the first overlay mark or an image of the second overlay mark,
• wherein the overlay measurement device is configured to:
• perform a focus scan at one site by controlling the auto focus module,
• determine a focus measurement area based on the performed focus scan,
• calculate statistical values for a plurality of parameters by moving the focus by one step within the determined focus measurement area for each site,
• apply a weight respectively to the calculated statistical values, and
• perform a focus optimization process of selecting a focus where a total of the statistical values to which the weight is applied respectively is a minimum value as a focus of the auto focus module.

A method of an overlay measurement device for measuring an error between a first overlay mark and a second overlay mark respectively formed on different layers of a wafer, the method comprising:

• receiving data from a user terminal, the data comprising information indicating whether to execute the optimization of measurement options of a wafer;
• analyzing a recipe that is included in the data;
• and
• when analyzing the recipe is completed and the data includes information indicating an execution of the optimization, performing optimization of measurement options of a wafer, based on the recipe,
• wherein the overlay measurement device comprises a light source, an objective lens that concentrates a beam from the light source on a measurement position of the wafer and gathers the beam being reflected in the measurement positon, a lens focus actuator that adjusts a distance between the objective lens and the wafer such that a focus surface is placed at the first overlay mark or the second overlay mark, an auto focus module that adjusts a focus by adjusting the lens focus actuator, and a detector for obtaining an image of the first overlay mark or an image of the second overlay mark, and
• wherein the optimization comprises:
• performing a focus scan at one site by controlling the auto focus module,
• determining a focus measurement area based on the performed focus scan,
• calculating statistical values for a plurality of parameters by moving the focus by one step within the determined focus measurement area for each site,
• applying a weight respectively to the calculated statistical values, and
• performing a focus optimization process of selecting a focus where a total of the statistical values to which the weight is applied respectively is a minimum value as a focus of the auto focus module.