Surface Modification

Any atomic force microscope can be used for creating nanometer-sized patterns on a surface. However, the quality and complexity of the patterns depends on specific scanning probe hardware and software. The method of patterning is determined by the types of probes, substrates, and the specific software performance capabilities used to drive the scanning probe tool.

Hardware: The most critical hardware feature that is required is an X-Y calibration system. Because the piezoelectric ceramics used in AFM have unwanted characteristics such as creep and hysteresis, calibration sensors are necessary to guide the motion of the probe. Without the calibration sensors, the probe moves in an unpredictable motion, and it is hard to write complex patterns. As an example, in figure 5 the AFM did not have calibration sensors, and the lines at the upper right of the pattern did not connect as intended. Conversely, Figure 6 is an illustration of a complex pattern drawn with the DPN™ process. Because the instrumentation had X-Y calibration sensors, a higher quality pattern was possible.

Software: Software is used for defining the pattern that will be drawn with an AFM and then for drawing the pattern on a materials surface. Figure 7 shows a control window that may be used for creating patterns with an AFM. The pattern may be drawn on a section of the screen as a combination of dots and lines or it may be imported from a bit-map file. The software allows writing of the patterns by applying a specific force or a specified voltage. Also, the rate of scanning can be specified.

Advanced DPN™ patterning involves the overlay of complex pattern layers with the precise deposition of molecules, and this process requires more complex instrumentation. NanoInk has developed a dedicated DPN™ Writer tool called NSCRIPTOR™. Built upon advanced PNI scanner technology, NSCRIPTOR™ offers a sophisticated, user-friendly DPN™ experience with integrated environmental control.