Specific Process Knowledge/Lithography/Aligners/Aligner: Maskless 01 processing: Difference between revisions
| Line 30: | Line 30: | ||
The table below shows the result of a resolution test using 1.5µm and 0.5µm positive resist. For 1.5µm resist the resolution is 2µm, maybe even a little lower, while it is 1µm, or at least close to, for 0.5µm resist. The optimal dose depends on the designed structures; dots require a lower dose in order to print to size than lines. In the case of a dark field design, trenches would probably require a lower dose in order to print to size than lines, while holes would require a higher dose to print than trenches. | The table below shows the result of a resolution test using 1.5µm and 0.5µm positive resist. For 1.5µm resist the resolution is 2µm, maybe even a little lower, while it is 1µm, or at least close to, for 0.5µm resist. The optimal dose depends on the designed structures; dots require a lower dose in order to print to size than lines. In the case of a dark field design, trenches would probably require a lower dose in order to print to size than lines, while holes would require a higher dose to print than trenches. | ||
Also evident in the pictures is the optical proximity effect (not to be confused with the proximity (gap) effect in contact lithography); corners are rounded, and the smallest lines show a different width for the central line compared to the outer ones. ''Optical Proximity Correction'' is the practice of augmenting the design in order achieve the desired size and shape in the finished print. A basic form of OPC is corner correction, also known as serifs, where a small square is added or subtracted at all corners. The last column in the table show the effect; the dots become square, and the short lines are the correct length. The effect of corner correction is significant below 2µm, but negligible above 4µm. The proximity effect on the width of the outer lines is not removed by corner correction; here so-called SRAF lines (''Sub-Resolution Assist Feature'') would be needed. | Also evident in the pictures is the optical proximity effect (not to be confused with the proximity (gap) effect in contact lithography); corners are rounded, and the smallest lines show a different width for the central line compared to the outer ones. ''Optical Proximity Correction'' is the practice of augmenting the design in order achieve the desired size and shape in the finished print. A basic form of OPC is corner correction, also known as serifs, where a small square is added or subtracted at all corners. The last column in the table show the effect; the dots become square, and the short lines are the correct length. The effect of corner correction is significant below 2µm, but negligible above 4µm. The proximity effect on the width of the outer lines is not removed by corner correction; here so-called SRAF lines (''Sub-Resolution Assist Feature''), also known as scatter bars, would be needed. | ||
{|border="1" cellspacing="0" cellpadding="3" style="text-align:left;" | {|border="1" cellspacing="0" cellpadding="3" style="text-align:left;" | ||