Double patterning process flow used in this experiment and discussed in text.
[(a)–(c)]. These figures show the stack and exposure location for each of the three experimental conditions just prior to the first etch process. At this point, the three stacks are the same, with an exposed pattern difference between the single image and nested topography.
[(a)–(c)] These figures show the stack and exposure location for each of the three experimental conditions just prior to the second etch process. At this point, the three stacks are different, with all the differences due to the silicon nitride hard mask pattern produced in the etcẖ1 process. (a) has a relatively isolated photoresist pattern exposed over an isolated hardmask pattern in the stack. (b) has a nested photoresist pattern exposed on arc and the stack only. (c) has a nested photoresist pattern exposed over a nested hardmask pattern. In the single image etcẖ2 topography diagram, the silicon nitride pattern stops a few microns prior to the measurement location. An example of this is shown in Fig. 4(a). Note that (b) is a separate test pattern from Fig. 2(b) to allow isolation from features on the other mask.
Single image and nested measurement locations. The single image and nested locations are on the same feature. The single image is twice the pitch of nested location.
Etcẖ1 features plotted by linewidth. Note that the etcẖ1 on ARC data is a measurement of the hard mask, while the other plots are polymeasurements.
Etcẖ2 features plotted by linewidth. All measurements are in poly.
Etcẖ1 residuals as a function of pitch for patterns on a substrate. At etch one, all three data sets demonstrate the same trend and magnitudes through pitch. The variation at each pitch location is due to different CD values at that pitch.
Etcẖ2 residuals for patterns from the second double patterning pattering step. In this case, there are three clear trends. The single image and nested double-patterned features have clearly different trends through pitch than that of the ARC only patterns. In addition, the single image and double image have different trends between them.
Stack data for the experimental process.
Article metrics loading...
Full text loading...