Mask Aligner

Devices and circuits are made optically using a high resolution contact/proximity optical mask aligner. The AB-M mask aligner is equipped with a light source covering both the near UV and deep UV spectrum. Patterns in the submicron range can be made on wafers up to 4 inches diameter. Major features:

Key Features:

• High resolution optical lithography (< 1 micrometer)
• 500 Watt XeHg light source with intensity controlling power supply
• 6" diameter collimated exposure beam
• Maximum wafer size: 4" in diameter
• User selectable output spectrum for either near UV or Deep UV exposure.
• Differential micrometers stage controls (X, Y and theta) for precision alignments
• Split field microscope with X,Y motion locking
• Accept mask up to 5" x 5"

Usage

• Photomask aligner is used to transfer patterns from photomasks onto a layer of photoresist that has been coated onto samples (chips or wafers). The process is silimar to that of printing a picture from a negtive film.

Limitations and Restrictions

• The maximum sample size can not be larger than 4" in diameter
• Resolution is determined by the gap between the photomask and the wafer. Therefore, to achieve a good resolution (<2 micrometers), the sample must be flat, and the photomask must be clean.
• For wafers, only 5" x 5" photomask can be used. For chips (< 1" x 1"), mask of size 3" x 3", 4" x 4" and 5" x 5" can be used.
• Available photo resists: S1813 for 1.3 micrometer thick coatings, and S1805 for 0.5 micrometer thick coatings