Optical mask, method for making figure and method for making semiconductor device

Abstract

A photomask includes a transparent substrate; a first mask pattern disposed on a first region of the transparent substrate; a second mask pattern disposed on a second region different from the first region of the transparent substrate; and a transparent film provided on the first mask pattern, having an optical thickness configured to make a focal position of the first mask pattern deeper than a focal position of the second mask pattern.

Description

[0001] Cross References to Related Applications [0002] This application is based upon and claims priority from prior Japanese Patent Application P2003-289008 filed on Aug. 7, 2003, the entire contents of which are incorporated herein by reference. technical field [0003] The present invention relates to photolithography, and more particularly to a photomask, a method of making patterns using a photomask, and a method of manufacturing semiconductor devices. Background technique [0004] When forming a circuit pattern of a semiconductor device, a photosensitive material such as a photoresist is coated on a working film on a semiconductor substrate, and then the photosensitive material is exposed and developed using a reduced projection photolithography machine. When using a photolithography machine with a refractive optical system, the light emitted from the light source passes through the illumination optical system and the projection optical system, and the circuit patter...

AI Technical Summary

Problems solved by technology

Therefore, there arises a problem that defocusing occurs in one surface of the interlayer dielectric film, and a correct photoresist pattern cannot be formed.

[0007] However, in some cases, it is not easy to set up a suitable dummy pattern in the sparse routing area

Therefore, it is difficult to achieve sufficient planarization on the surface of the interlayer dielectric film for focusing

In addition, due to the shortening of the light source wavelength due to the miniaturization of semiconductor integrated circuit patterns, the depth of focus becomes shallower

Therefore, even if the CMP process is applied by setting dummy patterns in the sparse wiring area, the generation of system steps cannot be completely suppressed

Therefore, it is difficult to achieve sufficient planarization on the surface of the interlayer dielectric film to obtain a suitable depth of focus

In this way, since the depth of focus of the photolithography machine is insufficient for the system step, the performance of forming patterns and the productivity of semiconductor devices are greatly reduced due to the generation of defects such as failure to transfer patterns with desired dimensions, such as wiring short-circuit or open-circuit failure The deterioration of the dimensional fidelity of the circuit pattern, and the collapse or spread of the resist pattern

Images