BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Analysis of Lithographic Alignment and Via Definition Challenges i n Multilayer TMR Fabrication Processes DTSTART:20260706T100000Z DTEND:20260706T120000Z DTSTAMP:20260918T191032Z UID:1db626e7-8be4-4373-b05c-7935f53882af SEQUENCE:1 CREATED:20260703T144326Z DESCRIPTION: The fabrication of TMR devices involves several microfabricat ion steps\, where lithography and layer alignment play a fundamental role in the proper definition of the structures. In this work\, the main challe nges of lithographic alignment and via definition were investigated in a m ultilayer fabrication process for TMR devicesFirstly\, X-shaped and Plus-s haped alignment marks were tested using different alignment strategies. Th e quality of the alignment was evaluated by overlay measurements\, taking into account the total offset and its components in the X and Y directions . The results showed that the lowest total overlay offset was obtained for condition X3\, with a value of 0.512 µm\, although geometry-dependent va riations were observed. The error in the X direction was reduced to 0.526 µm by using the Plus-shaped mark with offset correction\, demonstrating t he importance of directional overlay analysis.Then\, lithographic paramete rs such as development time\, focus offset and exposure dose were investig ated. The quality of the via opening was quantitatively evaluated by class ifying the vias as closed\, partially open and fully open. The best observ ed condition was obtained using 20 s of pre-development\, 60 s of developm ent\, an exposure dose of 50 mJ/cm² and a focus offset of 2V. This condit ion produced a total overlay offset of 0.949 µm and 68.75% fully open via s.The results demonstrate that via definition in multilayer TMR fabricatio n depends on the combined optimization of alignment\, development\, focus and exposure conditions. LAST-MODIFIED:20260703T144326Z LOCATION:Sala P12 (Piso 2 do Pavilhão de Matemática) do IST URL:http://df.vps.tecnico.ulisboa.pt/en/events/analysis-of-lithographic-al ignment-and-via-definition-challenges-in-multilayer-tmr-fabrication-proces ses/ X-ALT-DESC;FMTTYPE=text/html:

The fabrication of TMR devices involves several microfabrication steps\, where lithography a nd layer alignment play a fundamental role in the proper definition of the structures. In this work\, the main challenges of lithographic alignment and via definition were investigated in a multilayer fabrication process f or TMR devicesFirstly\, X-shaped and Plus-shaped alignment marks were test ed using different alignment strategies.

The quality of the alig nment was evaluated by overlay measurements\, taking into account the tota l offset and its components in the X and Y directions. The results showed that the lowest total overlay offset was obtained for condition X3\, with a value of 0.512 µm\, although geometry-dependent variations were observe d. The error in the X direction was reduced to 0.526 µm by using the Plus -shaped mark with offset correction\, demonstrating the importance of dire ctional overlay analysis.

Then\, lithographic parameters such as development time\, focus offset and exposure dose were investigated. The q uality of the via opening was quantitatively evaluated by classifying the vias as closed\, partially open and fully open. The best observed conditio n was obtained using 20 s of pre-development\, 60 s of development\, an ex posure dose of 50 mJ/cm² and a focus offset of 2V. This condition produce d a total overlay offset of 0.949 µm and 68.75% fully open vias.The resul ts demonstrate that via definition in multilayer TMR fabrication depends o n the combined optimization of alignment\, development\, focus and exposur e conditions.

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