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 uses:

  • Wafer thinning
  • Protective coatings
  • Multi-layer T-gate processes
  • Other direct-write e-beam processes

Material attributes:

  • Positive tone
  • E-beam and X-ray imageable
  • Wide range of film thicknesses
  • Resist developers and strippers
  • Excellent adhesion to most substrates

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. In addition, MMA (17.5) MAA copolymer resists are available upon request. All MCC 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

 Learn More

PMMA Data Sheet
Technical References: PMMA

    Wafer Thinning

Copyright MicroChem Corp.