Semiconductor wafer and manufacturing method thereof

A semiconductor wafer manufacturing method comprising the steps of:

• (a) preparing a first semiconductor wafer having a plurality of cuts formed at edge portions in crystal directions;
• (b) preparing a second semiconductor wafer having a cut formed at an edge portion in a crystal direction that is different from the crystal direction of one of said plurality of cuts of said first semiconductor wafer;
• (c) bonding said first and second semiconductor wafers to each other while using said one of said plurality of cuts of said first semiconductor wafer and said cut of said second semiconductor wafer in order to position said first and second semiconductor wafers, with another one of said plurality of cuts of said first semiconductor wafer being engaged with a guide portion of a semiconductor wafer manufacturing apparatus;
• (d) implanting oxygen ions from said first semiconductor wafer side into a neighborhood of a part where said first and second semiconductor wafers are bonded to each other;
• and
• (e) forming the portion implanted with the oxygen ions into an oxide film layer by a thermal treatment.