The wafer is then put through further processing to ensure its purity. It is inserted into an acid mixture that removes any abrasion caused by previous processes, then heated to a specific temperature to remove any impurities that might have been accidentally created when the crystal was formed. The wafer is then polished using highly sensitive equipment and cleaned in a solution of purified water and light cleansing agents.
The silicon wafers may be completed, but that does not mean it passed through all of its production processes undamaged. To make sure the wafer is pure enough and strong enough to be used for circuit boards, it is inspected to make sure that there are no flaws, that the flatness of the wafer is sufficient and that it has the proper resistance qualities.
It is therefore an object of the present invention to provide a silicon wafer capable of achieving a higher performance, higher yield and uniformity of characteristics of semiconductor devices comparable to a wafer provided with a pure epitaxial layer, without deteriorating the gettering ability of the silicon wafer. |
