The rising demand for processing small charges of ASICs, FPGAs or optolectronic devices at reduced costs promotes the application of e-beam direct-write lithography. This technology requires automated tools which integrate the overall processing sequence: coating, baking, developing, wet etching, stripping and cleaning. These tools should also enable clustering with e-beam writers and dry etchers for seamless processing. The novel integrated STEAG HamaTech ModuTrack track system enables automated processing of a batch of single substrates like wafers or photomasks, while for each substrate different processing methods and sequences may be chosen. The processing modules may also be operated individually. This integrated tool concept is demonstrated referring to the recently installed 8" wafer and 6" photomask ModuTrack at ITRI (Industrial Technology Research Institute of Taiwan), where the process development for wafer e-beam direct-write (EBDW) lithography and photomask processing is ongoing. The processing modules deliver outstanding capabilities, like coating resist with 50nm thickness within a total range of 1% uniformity, and developing 45nm resist dense lines both uniform and repeatable.
A mask patterning technology for the 90nm technology node has been developed using the FujifilmARCH resist FEP171 and the state-of-the-art mask making tools SteagHamaTech mask coater ASR5000, Leica 50kV variable shaped e-beam writer SB350, SteagHamaTech developer ASR5000 and UNAXIS Mask Etcher III. A resist resolution of below 100nm dense lines and 150nm contact holes was demonstrated. The line width shrinking due to chrome etching varies between 25nm and 50nm per feature and a corresponding resolution of 125nm dense lines in a 105nm thick chrome absorber has been achieved. The global CD-uniformity with a 3σ of 7.7nm and a total range of 10.8nm met the requirements of the ITRS roadmap. The local uniformity with a 3σ of 3.8nm and a range of 5.6nm offers potential for future application of the Leica SB350. Applying of a new correction method taking electron scattering and process characeristics into account provides a linearity of 6.1nm. In addition, the line width of different featurees was kept in a range up to 12nm when the local pattern density was changed. The composite placement accuracy of 12nm fulfills already the requirements of the 65nm node. A special investigation proved the excellent fogging depression of the SB350.
The new capillary spin (CAP-Spin) coating principle, realized in the STEAG HamaTech ASR5000, was evaluated for mask making using chemically amplified resists.
Basic correlations between coating parameters, resist thickness and film uniformity were figured out. We achieved a film thickness uniformity of close to 2% total range after a process optimization based on our investigation results with the positive tone resist JSR KRS-XE.
Finally, the performance of ASR coated blanks was assessed on the basis of a binary mask making process using the Fuji FEP171 resist. The ASR5000 was integrated in an advanced tool set and the patterned reticles have met the requirements of the 100nm Technology Node in terms of resolution and CD-uniformity. No correlation between thickness and CD distribution could be observed.
The evaluated post coating and post exposure delay influence of FEP171 also confirms the usability of the ASR5000 coated substrates for advanced mask making.
Utilizing the balance of capillary forces and adhesion, a liquid material, e.g. photo resist, can be applied to the surface of a face down mounted substrate. STEAG HamaTech's Advanced single Substrate Resist coater, ASR5000, is combining patented capillary apply technology, and a patented face-down spin process, to enable fringe free uniform coatings on rectangular substrates. CAP COATing technology reduces resist consumption by a factor of at least 10 over conventional coating methods. Face down spin, provides highly uniform resist spread without risk of backside contamination. The principle equipment concept and capability is presented.
Coating and bake performance is discussed for IP3600 and ZEP7000A. Coating uniformities, of smaller ±0.7% at a 4500Å thick IP3600 film and smaller ±0.4% at a 3000Å thick ZEP7000A resist film were achieved, respectively. The repeatability of the coating performance and the post coat bake process (PCB) are demonstrated.
Positive tone chemically amplified resists CAP209, EP012M (TOK), KRS-XE (JSR) and FEP171 (Fuji) were evaluated for mask making. The investigations were performed on an advanced tool set comprising of a Steag coater ASR5000, Steag developer ASP5000, 50kV e-beam writer Leica SB350, UNAXIS MASK ETCHER III , STS ICP silicon etcher and a CD-SEM KLA8100. We investigated and compared resolution, sensitivity, resist slope, dark field loss, CD-uniformity, line edge roughness, and etch resistance of the evaluated resists. Furthermore, the influence of post coating delay, post exposure delay and other process parameters on the resist performance was determined.
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