Phase displacement focal length detecting photomask, manufacture method and method for detecting focal length difference

Abstract

The invention provides a phase shift focus monitor reticle, a manufacturing method thereof, and a method of monitoring focus difference using the phase shift focus monitor reticle. The phase shift focus monitor reticle comprises a shield comprising a plurality of light-transmitting portions with a certain width; and a glass layer positioned on the shield layer comprising a plurality of openings at the light-transmitting portions; wherein the width of the openings is half of the width of the light-transmitting portions; the depth of the openings is n*λ / (N−1), wherein λ is the wavelength of the lights incident on the phase shift focus monitor reticle in air, N is the refractive index of the glass layer, n is a positive integer. The invention can be applied to thicker photoresist and different process machines.

Description

technical field [0001] The invention relates to the field of microelectronics, in particular to a phase-shift focus detection mask, a manufacturing method thereof, and a method for using the phase-shift focus detection mask to detect the focus difference of a photolithography machine. Background technique [0002] Lithography machine is an important lithography equipment for large-scale integrated circuits, sensors, surface wave components, magnetic bubbles, microwaves and CCDs in semiconductor production and experimental manufacturing. The photolithography process transfers the pattern on the mask to the photoresist coated on the surface of the wafer by exposure, and then transfers the pattern to the wafer by developing, etching and other processes. The photolithography process directly determines the feature size of large-scale integrated circuits, and is a key process in the manufacture of large-scale integrated circuits. [0003] The focal length of the lithography mach...

AI Technical Summary

Problems solved by technology

But because figure 1 The structure in the photomask can only change the vertical light into oblique light in a small area near the opening (in the chrome frame). This kind of mask can only put a very narrow line measurement mark (Line mark) for overlay precision machine The photoresist must be very thin in order to make the strip line measurement mark on the wafer not pour the glue.

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