Pattern dimension measuring apparatus and pattern area measuring method

A pattern dimension measuring apparatus comprising:

• a unit for irradiating an electron beam onto a sample in a scanning manner;
• a unit for acquiring image data of a pattern according to the quantity of electrons emitted, by irradiation of the electron beam, from a surface of the sample where the pattern is formed;
• an area measuring unit for dividing the pattern into a plurality of partial patterns, calculating the areas of the partial patterns, and calculating the area of the pattern by summing up the areas of the partial patterns,
• a line profile creating unit for creating a line profile to represent a luminance signal on a predetermined line out of the image data;
• and
• a differential profile creating unit for creating a differential profile by differentiating the line profile,
• wherein the area measuring unit detects edge positions around the pattern at a predetermined interval;
• and calculates the area of the pattern by subtracting a total area of trapezoidal regions each being defined by the two detected edge positions adjacent to each other and excluding partial patterns obtained by dividing the pattern, from a total area of trapezoidal regions each being defined by two detected edge positions adjacent to each other and including the partial patterns, and
• wherein the area measuring unit detects the edge positions around the pattern at the predetermined interval:
• by detecting and defining a first edge position of the pattern as a starting-point edge position;
• by detecting and defining a second edge position at a predetermined distance away from the starting-point edge position as a temporary edge position;
• by detecting a third edge position by use of the line profile and the differential profile on a line perpendicularly passing the middle point on a segment connecting the starting-point edge position and the temporary edge position;
• and by detecting a new edge position adjacent to the third edge position while defining the third edge position as the new starting-point edge position.

A pattern area measuring method to be executed by a pattern dimension measuring apparatus provided with a unit for irradiating an electron beam onto a sample in a scanning manner, a unit for acquiring image data of a pattern according to the quantity of electrons emitted, by irradiation of the electron beam, from a surface of the sample where the pattern is formed, a line profile creating unit for creating a line profile to represent a luminance signal on a predetermined line out of the image data, and a differential profile creating unit for creating a differential profile by differentiating the line profile, the method comprising the steps of:

• acquiring an image of a pattern in a measurement target range;
• dividing the pattern into a plurality of partial patterns;
• calculating the areas of the partial patterns;
• and
• calculating the area of the pattern by summing up the areas of the partial patterns,
• wherein, when the pattern is a rectangular pattern surrounded by opposed first and second edges, the step of dividing the pattern into a plurality of partial patterns further comprises the steps of:
• dividing the pattern into rectangular partial patterns by sectioning the opposed first edges into a predetermined length;
• creating the line profile on a line being parallel to the opposed second edges and intersecting the opposed first edges for each of the rectangular partial patterns;
• creating the differential profile by differentiating the line profile;
• and
• calculating the distance between the first edges by detecting the position of the first edges in each of the partial patterns by use of the line profile and the differential profile.

A pattern area measuring method to be executed by a pattern dimension measuring apparatus provided with a unit for irradiating an electron beam onto a sample in a scanning manner, a unit for acquiring image data of a pattern according to the quantity of electrons emitted, by irradiation of the electron beam, from a surface of the sample where the pattern is formed, a line profile creating unit for creating a line profile to represent a luminance signal on a predetermined line out of the image data, and a differential profile creating unit for creating a differential profile by differentiating the line profile, the method comprising the steps of:

• acquiring an image of a pattern in a measurement target range;
• dividing the pattern into a plurality of partial patterns;
• calculating the areas of the partial patterns;
• and
• calculating the area of the pattern by summing up the areas of the partial patterns,
• wherein the step of dividing the pattern into a plurality of partial patterns further comprises the steps of:
• detecting and defining an edge position of the pattern as a starting-point edge position, and detecting and defining an edge position at a predetermined distance away from the starting-point edge position as a temporary edge position;
• creating the line profile on a line perpendicularly passing the middle point on a segment connecting the starting-point edge position and the temporary edge position;
• creating the differential profile by differentiating the line profile;
• detecting a third edge position by use of the line profile and the differential profile;
• detecting edge positions around the pattern by defining the third edge position as the new starting-point position, and by detecting a new edge position adjacent to the third edge position;
• and
• dividing the pattern into trapezoidal regions each defined by two edge positions adjacent to each other and including partial patterns obtained by dividing the pattern,
• wherein the step of calculating the area of the pattern is the step of subtracting a total area of trapezoidal regions excluding the partial patterns from a total area of the trapezoidal regions including the partial patterns.