PMMA positive resists are based on special grades of polymethyl methacrylate designed to provide high contrast, high resolution for e-beam, deep UV (220-250nm) and X-ray lithographic processes. In addition, PMMA is often used as a protective layer in III-V device wafer thinning applications. Standard products include 495,000 and 950,000 molecular weights (MW) in a wide range of film thicknesses formulated in chlorobenzene, or the safer solvent anisole. In addition 50,000, 100,000, 200,000 and 2.2 million MW are available upon request.

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 processes where independent control of CD size and shape of each resist layer is required. Standard copolymer resists are formulated in the safer solvent ethyl lactate and are available in a wide range of film thicknesses. In addition, MMA (17.5) MAA copolymer resists are available upon request.

		Product Attributes					Applications for PMMA & copolymer resists

	Sub 0.1µm imaging E-beam, Deep UV and X-ray imagable Broad range of molecular weights & dilutions Compatible with multi-layer processes Excellent adhesion to most substrates				Multi-layer T-gate processes Other direct write e-beam processes Protective layer for III-V device wafer thinning