Polyamic acids, polyimides prepared from these and process for producing high-temperature resistant layers
US4871833A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 4, 1987 |
| Grant date | Oct 3, 1989 |
| Priority date | — |
| Expiry date | May 4, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G73/1078
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Described are polyamic acids, at least 50 mole-% of which are comprised of recurrent units corresponding to the general formula I: ##STR1## wherein, R.sup.1 is a mono-, di-, tri- or tetranuclear aromatic group and PA0 X is O, S, CO, SO.sub.2 or CR.sup.2 R.sup.3, each one of PA0 R.sup.2 and R.sup.3 being H or CH.sub.3. A polyamic acid of the present invention, in the form of a solution, is applied to a substrate, for example, a semiconductor device, to form a protective layer thereon, and is converted into polyimide by heating. As against comparable compounds known in the art, the polyamic acids of the present invention are distinguished by a lower inherent viscosity at an unchanged molecular weight and, consequently, by an improved processability at an equally good thermal stability.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.