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25 October 2002

Edge polisher introduction to patterned/device wafer applications


The SpeedFam line up expands with the adoption of our Edge Polishing systems by IC chip manufacturers to improve yields. Our edge polishers are proven in the production of 300mm, 200mm, and 150mm device wafer fabrication.
The edge, as well as the surfaces of prime silicon wafers, are polished prior to shipment to device manufacturers. However, organic pollution and defects occur in the FAB process due to deposition of films causing detachment of insulation layers and metal membranes, alien substance adhesion, outbreaks of gases in annealing, and metallization steps during fabrication processes. It is known that the wafer edge is a primary source of yield lowering defects. These edge defects and particles are easily transferred to the wiring surface during the semiconductor process. This yield affecting pollution if evident at both back (BEOL) end and front end (FEOL) process nodes. It is further evident that the edges of wafers are most susceptible to defects due to handling and storing and that these defects are easily transferred from wafer to wafer via machine chamber contamination etc.
In addition, the accumulation of these particulates is becoming more of a concern as line widths shrink and copper is becoming the process of choice. The degree of cleanliness at the edge (top and bottom) is more important than ever to eliminate FEOL contamination at the start of metallization layers as well as left over residues especially at the 65nm and below design rules at BEOL as well.
The SpeedFam edge polisher removes alien substances from wafer edges by mechanochemical polishing to return the edge condition to the same state as the original prime wafer (simple cleaning cannot do this). Edge polishing is specific to each device specification. Edge polishing can eliminate defects and prepare the edge for a better subsequent process yield when utilized before, or after, etching processes, film processes, annealing process and CMP etc.
The latest models of SpeedFam Edge Polishers process all three edge regions at the same time (upper, lower, apex) . There is no faster or more effective method to smooth, repair and clean wafer edges to this prime quality level. In addition, we integrate polishing units for orientation flats or notches as well. Our EPD equipment is also available with post polish cleaning and drying of the wafer surfaces and edges as well, providing users with device FAB ready dry in dry out production.
We will show an actual EPD-300 machine at "SEMICON Japan 2002" starting on Wednesday, 4th December at Makuhari Messe. We will also have the consumables for this process on display.

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