AZ 1505
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AZ 1505 is a positive tone photoresist which is sensitive to UV light in the range 310 - 410 nm. It draws its name from the company that initially developed it (AZ), the photoresist product series (1500), and the thickness that it spins to at 4000 RPM (0.5 µm).
Quick facts
- Solid contents: 17.7%
- Solvent: methoxy-propyl acetate (PGMEA)
- Photoactive compound: diazonaphtoquinone-(DNQ-)sulfonate
- Responds to the Mercury I, H, and G lines
- Suitable for both wet or dry etching
Processing guidelines
- Spin at 4000 RPM for 45 s. This yields a film thickness of 0.5 µm.
- Softbake at 100°C on a hotplate for 1 minute. Note: The longer the baking time, the lower the solvent concentration. Softbaking for too short or too cool may cause bubbling and foaming of the resist due to the generation of nitrogen during UV exposure. Softbaking for too long or too hot will decompose a fraction of the DNQ, and decrease the development rate.
- Expose your pattern
- An optional post-exposure bake may be performed to reduce standing wave patterns that may occur.
- Develop in your developer of choice:
- AZ 351B: The standard developer for this resist. For high contrast, develop for 60 s with mild agitation in a dilution of 1:5 with water. This developer is based on buffered NaOH, and thus attacks aluminium.
- AZ 400K: For high contrast, develop for 1-3 min with mild agitation in a dilution of 1:4 with water. This developer seems primarily geared for thicker photoresist (e.g. AZ 4500 series). It is based on buffered KOH, and thus attacks aluminium.
- AZ developer: For highest contrast, use a dilution of 1:1 with water and develop for 60 s with mild agitation. This developer contains sodium metasilicate, and sodium phosphate, and is tuned for the lowest attack of aluminium. The dark erosion is slightly than for the other developers.
- Other metal ion free (MIF) developers may be used if Na og K ions are detrimental to your device.
- Rinse immediately with MQ water.
- A hardbake may be performed to enhance the etch resistance of the resist, but is otherwise not recommended, especially if a subsequent metal lift-off process is planned due as this causes the resist to reflow and ruins the undercut.
Dose Test
The figure shows the height of the squares measured by SEM after the lift-off process as a function of dose and defocus. The aimed height was of 5 µm.