Dual etching of ceramic materials
US5466332A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 4, 1994 |
| Grant date | Nov 14, 1995 |
| Priority date | — |
| Expiry date | Apr 4, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B2111/00844
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A novel method etching through a substrate (e.g. BST 22) comprises removi A n5 Vthick substrate material from the backside of the substrate to form vias (e.g. cavity 24) all the way to the back surface of a frontside thin film (e.g. optical coating 20). To prevent damage to the frontside thin film while etching from the backside of the supporting substrate, the periphery of each frontside pixel is surrounded by a trench (e.g. etch stop trench 30) much deeper than the thickness of the thin film but also significantly shallower than the thickness of the substrate. This trench is then filled with an etch stop material (e.g. photoresist 32). This etch stop may be partially removed by the backside etching method but provides a tolerant means of recognizing when to stop etching before frontside film damage occurs. After etching the substrate down to and partially through the etch stop, the assembly is removed from the substrate etching medium. The remaining etch stop material may be removed with a specific agent which does not damage the frontside film. For example, if the etch stop is an organic material, such as photoresist, it may be removed from the back with a suitable solvent or dr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.