Non contact measuring method for three dimensional micro pattern in measuring object

DETAILED DESCRIPTION The present invention is directed to overcome the drawbacks and problems as set forth above.
It is an object of the present invention to provide a non-contacting measuring method for three dimensional micro pattern in a measuring object using an optical window and blurred images, giving in high measuring accuracy and simple measuring environment.
It is another object of the present invention to provide a non-contacting measuring method for three dimensional micro pattern in a measuring object using an optical window and blurred images, giving quantitative measurement of the surface of the measuring object with few nanometer resolution of depth profile.
According to the present invention, these objects are achieved.
There is provided a non-contacting measuring method for three dimensional micro pattern in a measuring object comprising the steps of: (a) forming light emitted from a source into slit-shaped light by means of an optical window; (b) applying the slit-shaped light to a first scanning measurement line with a micro width of the measuring object with a plurality of surfaces which have step heights wherein each of the surfaces has three dimensional micro depth profile; (c) finding a reference surface among the surfaces by passing the light reflected from the surfaces through a lens and capturing images of the surfaces on a screen wherein the reference surface is in focus on the screen; (d) finding a reference position in the reference surface whose image is sharp in focus on the screen wherein images of the other positions except the reference position are blurred out of focus on the screen; (e) measuring a size of the sharp image corresponding to the reference position and sizes of the images with blurred image corresponding to the other positions; (f) calculating ratio values of the sizes of the images with the blurred image to the size of the sharp image corresponding to the reference position; (g) obtaining relative height differences between the reference position and the other positions; (h) establishing a relation equation between ratio value and relative height difference by the ratio values of the sizes of the images with the blurred image to the size of the sharp image and the relative height differences between the reference position and the other positions wherein the relation equation between the ratio value and the relative height difference is given as