Backside Metal Sputtering Deposition
The back side metal sputtering deposition process ionizes Ar atoms into secondary electrons and Ar ions in a high vacuum environment. It then sputters depositing metals bombarded out of the target material by accelerating Ar ions with the negative potential of the target.What ProPowertek can do for you?
The ProPowertek is here to automate back side metal sputtering depositing thinned wafers (by grinding and other measures) with exclusive machine equipment to layer the wafer with metallic bonding pads. The latter may come in Ti / NiV / Ag as required by MOSFET or Al / Ti / NiV / Ag by IGBT.
Back side metal sputtering deposition process
Equipment of the process is subject to regular reliability testing over individual chambers with control wafers at a fixed time. The ICP reaction chambers are subject to etching rate tests and deposition and uniformity testss for Al, Ti, NiV, and Ag. Once tested successful, products will be made as scheduled. Wafers of customers, once IQC’d, may go through pre-deposition DHF washing or go in the sputtering machine immediately. Wafers are then deposited by metal sputtering in types, thickness, and ICP conditions set by customers before going through nitrogen annealing or OQC.
The Superiority of ProPowertek
- Metal combination of Al / Ti / NiV / Ag and Ti / NiV / Ag.
- Automatic thin wafer sputtering without any human intervention.
- Provide pre-sputtering washing to prevent a native oxide layer and help the forming of Al spiking.
- Provide high-temperature nitrogen oven for post-sputtering annealing as required by customers.
- Metals sputtered with good adhesion and without peeling after 1000 hours of reliability testing at a temperature of 85°C and relative humidity of 85%.
- The engineer team of ProPowertek comes with diverse backgrounds, including experts from front-end wafer foundries, wafer thinning, and back-end assembly houses. The team excels at integration and analysis of the front, middle and back stages which benefits our customers for rapid development, problem solving, and reliable mass production.
Case Sharing
Non-metal Peeling
Peeling tests over gap etched wafers after metal sputtering ended without any peeling effects.
Wafers subject to 1000 hours of reliability testing at a temperature of 85°C, relative humidity of 85% and die sawing ended up without any peeling after going through the peeling test with blue tape.
N-type wafer subject to peeling test
P-type wafer subject to peeling test
Shear force by ball shear test according to specification JESD22-B117B came in at over 350gf and better than the 226gf set by the automotive specification.
Application
- Existing combination of metals: Al / Ti / NiV / Ag or Ti / NiV / Ag with varying thickness as required by customers
- Applicable with 8" wafer
- Al / Ti / NiV / Ag grew in excellent uniformity
- Back side metal layer of MOSFET and IGBT
