Phase shift mask and fabrication method thereof

Abstract

The invention discloses a phase shift mask and a fabrication method thereof. The phase shift mask for transferring a layout in a photolithography process includes a substrate and a patterned phase shift layer. The patterned phase shift layer is disposed on the substrate and includes at least one device pattern aperture and a plurality of dummy pattern apertures, the device pattern aperture and thedummy pattern apertures expose the surface of the substrate, and the dummy pattern apertures are disposed around the device pattern aperture. The patterned phase shift layer has a predetermined thickness such that the phase difference between the light passing through the patterned phase shift layer and the light passing through the device pattern aperture or the dummy pattern apertures during the photolithography process is 180 degrees. The transmittance ratio of the patterned phase shift layer is 100%.

Description

technical field [0001] The invention relates to a photomask and a manufacturing method thereof, in particular to a phase-shift photomask and a manufacturing method thereof. Background technique [0002] Generally, semiconductor elements need to be completed through complicated semiconductor manufacturing processes, and various circuit layouts on the chip need to be defined and formed by multi-pass photolithography manufacturing processes. In the lithography process, the exposure resolution (resolution) is an important index of lithography quality, and the phase shift mask (phase shift mask, PSM) is developed to improve the resolution of the lithography process. a photomask. However, in the existing methods for making phase-shift photomasks, the phase-shift layer is mainly made of molybdenum silicon (MoSi) material, which must include multiple etching processes, and it is difficult to avoid the impact of these etching processes on the substrate during the manufacturing proce...

AI Technical Summary

Problems solved by technology

However, in the existing methods for making phase-shift photomasks, the phase-shift layer is mainly made of molybdenum silicon (MoSi) material, which must include multiple etching processes, and it is difficult to avoid the impact of these etching processes on the substrate during the manufacturing process. Damage caused by the surface or phase shift layer, which reduces the uniformity of the critical dimensions (CD) of the pattern on the photomask

In addition, the light transmittance of the molybdenum silicon material in the existing phase-shift photomask is only about 6%, so the resolution is low, and there is also a side lobe effect (side lobe effect), that is, in the exposure manufacturing process, For example, the vicinity of circuit patterns such as contact holes will be exposed to defect patterns that were not on the original layout

Images