PMMA Positive Resists
PMMA (polymethyl methacrylate) is a versatile polymeric material that is well-suited for many imaging and non-imaging microelectronic applications. PMMA resists are simply PMMA polymer dissolved in a solvent like anisole (safe solvent). Exposure causes scission of the polymer chains. PMMA is most commonly used as a high resolution positive resist for direct write e-beam offering extremely high-resolution, ease of handling and excellent film characteristics. PMMA is also used as a protective coating for wafer thinning, as a bonding adhesive and as a sacrificial layer.
Material attributes:
· Positive tone
· E-beam and X-ray imageable
· Wide range of film thicknesses
· Resist developers and strippers
· Excellent adhesion to most substrates
Material uses:
· Wafer thinning
· Protective coatings
· PHEMT
· Multi-layer T-gate processes
· Other direct-write e-beam processes
Copolymer resists are based on a mixture of PMMA and ~8.5% methacrylic acid. Copolymer MMA (8.5) MAA is commonly used in combination with PMMA in bi-layer lift-off resist process where independent control of CD size and shape of each resist layer is required. Standard copolymer resists are formulated in ethyl lactate and are available in a wide range of film thicknesses. All PMMA and copolymer resists are available in package sizes from 500ml to 20 liters.
Material uses:
· Multi-layer T-gate processes
· Other direct write e-beam processes
Material attributes:
· Compatible with multi-layer processes
· Excellent adhesion to most substrates
Schematic of a T-gate illustrating various product layers
MODEL
MMA(8.5)MMA EL12
MMA(8.5)MMA EL9
MMA(8.5)MMA EL6
MODEL
495 PMMA C6
495 PMMA C4
495 PMMA C2
495 PMMA C9
495 PMMA C8
495 PMMA A6
495 PMMA A4
495 PMMA A2
495 PMMA A11
495 PMMA A8
950 PMMA C10
950 PMMA C9
950 PMMA C7
950 PMMA C4
950 PMMA C2
950 PMMA A11
950 PMMA A9
950 PMMA A7
950 PMMA A4
950 PMMA A2
