| abstract |
This invention relates to curable epoxy-based compositions for use in the field of microelectronics, such as those having an epoxy compound which has two or more epoxy groups per molecule, optionally a polythiol compound which has two or more thiol groups per molecule, a latent hardener, and at least one solid organic acid which is substantially insoluble in a mixture of the foregoing components at room temperature. The solid organic acid may be selected from the group consisting of: aliphatic, cycloaliphatic and aromatic carboxylic acids and derivatives thereof, aliphatic, cycloaliphatic, and aromatic quinones and derivatives thereof, phenols and derivatives thereof and enolisable aliphatic, cycloaliphatic and aromatic compounds and derivatives thereof. The solid organic acid should have a pKa of less than or equal to about 12.0, desirably less than or equal to about 10, and often less than or equal to about 9.0, such as less than or equal to about 7.5. The invention also relates to curable epoxy-based compositions including an epoxy compound, a thixotropy-conferring component, a latent hardener and at least one of the solid organic acids above demonstrating improved rheological properties such as yield point maintenance and viscosity maintenance over time. |