| Popis: |
New I-line resists are claimed to be usable at 0.35 micrometers design rules. We have examined the suitability of several such materials (JSR IX750, Sumitomo PFi-38a, OCG RX64I) for this purpose and compared them with our production 0.5 micrometers resist, JSR IX700. A variety of criteria have been used, including the measured focus exposure windows at e-min and e-max, DOF vs. CD for grouped and isolated lines as well as contacts, linearity, and proximity response as a function of pitch. A limited study has been done on the impact of embedded phase shift reticles on printing small geometry contacts. We report upon the process improvements observed with two different reticle transmissions, their impact on isofocal bias, as well as the issue of sidelobe formation. Proponents of DUV claim that modern DUV materials exhibit significant advantages in terms of process window and more over are applicable to smaller geometries without the need for supplementary techniques such as phase shifting or modified illumination. In this study, we have examined the performance of a number of DUV materials (BASF ST3.5, OCG ARCH, JSR KRFL2 and an as yet experimental JSR resists) on ASM-L and Nikon excimer laser steppers. Limited results were also obtained using Shipley 2408 and dyed XP-9444 (0.8) on the SVG Micrascan II. Our studies conclude with a comparison of the CD swing observed over a variety of chemically mechanically planarized steps. This has been done for selected I-line and DUV resists with the aid of a TAR or BARC or as in the case of the broad band SVG system either a BARC or a dyed resist. |
