Ionic additives for extreme low dielectric constant chemical formulations
US6576568B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Mar 29, 2001 |
| Grant date | Jun 10, 2003 |
| Priority date | — |
| Expiry date | Mar 29, 2021 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/249969
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A process for depositing porous silicon oxide-based films using a sol-gel approach utilizing a precursor solution formulation which includes a purified nonionic surfactant and an additive among other components, where the additive is either an ionic additive or an amine additive which forms an ionic ammonium type salt in the acidic precursor solution. Using this precursor solution formulation enables formation of a film having a dielectric constant less than 2.5, appropriate mechanical properties, and minimal levels of alkali metal impurities. In one embodiment, this is achieved by purifying the surfactant and adding ionic or amine additives such as tetraalkylammonium salts and amines to the stock precursor solution. In some embodiments, the ionic additive is a compound chosen from a group of cationic additives of the general composition [NR(CH3)3]+A−, where R is a hydrophobic ligand of chain length 1 to 24, including tetramethylammonium and cetyltrimethylammonium, and A− is an anion, which may be chosen from the group consisting essentially of formate, nitrate, oxalate, acetate, phosphate, carbonate, and hydroxide and combinations thereof. Tetramethylammonium salts, or…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.