I & g-line steppers

Nano to Micro/Macro (Micro-fabrication)

The projection systems, commonly known as ‘steppers’, exhibit several advantages as a higher resolution and prevention of photo-mask damage. In these systems, the image of the patterns in the masks is projected onto the photoresist-covered substrate at a distance of several centimeters. To achieve a high resolution, only a small portion of the mask is transferred. In the case of the projection “by steps”, the photo-mask only contains one chip or group of small chips that will be repeated across the whole wafer, and whose size has been increased by a factor 5 or 10. This increased image of the pattern repetition unit is then reduced back to its real size and projected to the surface by a highly precise optical system. After this projection, the substrate is moved in a prefixed step and the operation is repeated. Thanks to this ‘step-and-repeat’ systems, resolutions lower than 1 micron are easily achievable.

Usually the source of light that is used for the photoresist exposition is UV light produced by a Hg lamp, in the wavelength region of 366 (i-line) and 436 nm (g-line). Several variables must be regularly controlled as are the light collimation and diffraction, and its intensity variation with time, the exposition spectrum, the mask reflection, the uniformity of light absorption in the photo-resist…

          provided at NFFA-Europe laboratories by:
Stepper Nikon NSR 2205i12D (F24)
I-line projection photolithography step and repeat system
Soft UV source
365nm (i-line)
Better than 400 nm
Automatic alignment with fine positioning and automatic correction X-Y precision better than 10nm Focus positioning (Z) precision of 10nm Angle (J) positioning/correction: 10 mrad
100 mm or 150 mm wafers, without CMOS contaminant metals (alkalines, noble metals) Reticles of 6”x 6”
Ambient (class 100 clean room)
Optical microscope
Allows multiple designs in one reticle
Automatic resist coater/developer Süss Gama 80 Manual spinners and hot-plates