Method for fabricating equal height metal pillars of different diameters
US9324557B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 2014 |
| Grant date | Apr 26, 2016 |
| Priority date | — |
| Expiry date | Jun 4, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/37
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A process to form metal pillars on a flip-chip device. The pillars, along with a layer of solder, will be used to bond die pads on the device to respective substrate pads on a substrate. A photoresist is deposited over the device and a first set of die pads on the device are exposed by forming openings of a first diameter in the photoresist. Pillars of the first diameter are formed by electroplating metal onto the exposed die pads. Then a second photoresist deposited over the first photoresist covers the pillars of the first diameter. Openings of a second diameter are formed in the first and second photoresists to expose a second set of die pads. Pillars of the second diameter are formed by electroplating metal onto the exposed die pads. The photoresists are then removed along with conductive layers on the device used as part of the plating process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.