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OnChip Offers Onshore Silicon Wafer Backend Processing

SANTA, CLARA, Calif.—OnChip recently announced the availability of its onshore backend wafer processing services. The company’s services include silicon wafer back-lap, various back-metal schemes, a wide range of wafer sort and test capabilities, sawing, die pick-and-place into waffle packs or gel packs, and final visual inspection.

Following is a summary of the company’s onshore services.

Backgrinding
Backgrinding, lapping, or mechanical polishing are methods used to reduce thickness of wafers to attain a desired size (down to 100 microns or 4 mils) or surface texture (ultra-fine finish of 2000-Grit). Proper backside surface finish is key to remove native oxide growth and ensure ideal back-metal adhesion. OnChip’s machines are capable of processing wafers ranging in size from 100 mm (4 inches) to 200 mm (8 inches). Standard lead-times are between 24-48 hours.

Back-metallization
OnChip’s systems deposit ultra-clean metal and dielectric films in a class-100 cleanroom. Generally, an in-situ RF etch is performed prior to sequential deposition of multilayers to ensure good film adhesion and ohmic contact to underlying conductive layers or to the bare silicon. The most common metal stack consists of sputter deposited titanium (500 Angstroms), followed by nickel (3,000 Angstroms), and, finally, a flash of gold (200 Angstroms). All sputter films are currently available on silicon wafer sizes up to 150 mm (6 inches) in diameter. Larger wafer sizes may be considered on a case-by-case basis.

Testing
OnChip can process high volume while promising to deliver short lead-times and competitive prices. The company offers both wafer probe (including bumped wafer probe) and final test. Its fully automatic wafer probers are said to be capable of processing wafers up to 200 mm (8 inches). A wide range of automated test equipment allows for testing of analog, digital, mixed-signal, and RF technologies with probers and handlers to support wafer sort and package test. Multi-site wafer probing at hot temperature (up to 200°C) is available.

Dicing
The company’s dicing machines are said to be capable of processing fragments and partial wafers to 200 mm (8 inches) silicon wafers. Additionally, other materials, such as gallium arsenide, micro-electro-mechanical systems (MEMS), and LEDs can also be processed. Dicing precision of less than 2 microns and kerf of less than 16 microns can be achieved.

Die Loading
OnChip offers automated and manual loading of parts, as well as automated pick-and-place of die into packages, including gel packs and waffle packs. Manual pick-and-place via vacuum pen can also be requested for parts that are unpassivated, sensitive (moisture sensitive devices), MEMS, or require topside handling.