Investigation of the Influence of the Design of Alignment Marks and the Used Diffraction Order on the Amount of Overlay in Submicron Photolithography in the Formation of Thick-Film Aluminum Wiring of Silicon Semiconductor Structures

In this work the signal level dependences of diffraction gratings were obtained in the scribe line SPM AH11 and SPM AH53 used by the exposure equipment during alignment and aluminum films of 2, 2.6, 3, and 4 µm thickness formed over the marks using the 1st, 3rd, 5th, and 7th orders of diffraction. The minimum value of misalignment to the previous topological pattern through layers of aluminum films with a thickness of 2 μm was obtained by overlay using the SPM AH53 marks and the 3rd-order diffraction signal. This is due to the sufficient level and shorter period of the signal received from the diffraction grating during its exposure, due to which it was possible to determine the center of the alignment mark. For aluminum films with a thickness of 2.6, 3, and 4 μm, a minimum misalignment of topological patterns was achieved by overlay using SPM AH53 marks and the 5th-order diffraction signal. The use of the SPM AH53 alignment mark for the formation of aluminum wiring with a thickness of 2 to 4 μm allows to solve the problem of ensuring the minimum value of wafer overlay for the manufacture of silicon submicron semiconductor devices, in particular, powerful MDS transistor structures.