Epitaxy metrology in fin field effect transistors

A computerized method of performing a measurement with respect to an epitaxy formed in a fin field effect transistor (finFET), the epitaxy being separated with at least one adjacent epitaxy by at least one high-k (HK) fin, the method performed by a processing and memory circuitry (PMC), the method comprising:

• obtaining an image representative of the epitaxy and the at least one HK fin, and a gray level (GL) profile indicative of GL distribution of the image;
• detecting edges of the at least one HK fin on the image based on the GL profile;
• determining two inflection points of the GL profile within an area of interest in the image at least based on the detected edges of the at least one HK fin, the inflection points being indicative of expected presence of edges of the epitaxy;
• performing a critical dimension (CD) measurement between the two inflection points;
• determining whether to apply correction to the CD measurement based on a GL ratio indicative of a relative position of the epitaxy with respect to the at least one HK fin;
• and
• applying correction to the CD measurement upon the GL ratio meeting a predetermined criterion.

A non-transitory computer readable storage medium tangibly embodying a program of instructions that, when executed by a computer, cause the computer to perform a method of performing a measurement with respect to an epitaxy formed in a fin field effect transistor (finFET), the epitaxy being separated with at least one adjacent epitaxy by at least one high-k (HK) fin, the method comprising:

• obtaining an image representative of the epitaxy and the at least one HK fin, and a gray level (GL) profile indicative of GL distribution of the image;
• detecting edges of the at least one HK fin on the image based on the GL profile;
• determining two inflection points of the GL profile within an area of interest in the image at least based on the detected edges of the at least one HK fin, the inflection points being indicative of expected presence of edges of the epitaxy;
• performing a critical dimension (CD) measurement between the two inflection points;
• determining whether to apply correction to the CD measurement based on a GL ratio indicative of a relative position of the epitaxy with respect to the at least one HK fin;
• and
• applying correction to the CD measurement upon the GL ratio meeting a predetermined criterion.