Method for manufacturing bonded wafer and outer-peripheral grinding machine of bonded wafer
The present invention provides a method for manufacturing a bonded wafer, which includes at least the steps of bonding a bond wafer and a base wafer, grinding an outer peripheral portion of the bonded bond wafer, etching off an unbonded portion of the ground bond wafer, and then reducing a thickness of the bond wafer, wherein, in the step of grinding the outer peripheral portion, the bonded bond wafer is ground so as to form a groove along the outer peripheral portion of the bond wafer to form an outer edge portion outside the groove; and in the subsequent step of etching, the outer edge portion is removed together with the groove portion of the bond wafer to form a terrace portion where the base wafer is exposed at the outer peripheral portion of the bonded wafer. Thus, it is possible to provide a method for manufacturing a bonded wafer, which can reduce the number of dimples formed in a terrace portion of a base wafer upon removing an outer peripheral portion of a bonded bond wafer.
1. A method for manufacturing a bonded wafer comprising at least the steps of bonding a bond wafer and a base wafer, grinding an outer peripheral portion of the bonded bond wafer, etching off an unbonded portion of the ground bond wafer, and then reducing a thickness of the bond wafer, wherein:
in the step of grinding the outer peripheral portion, the bonded bond wafer is ground so as to form a groove along the outer peripheral portion of the bond wafer to form an outer edge portion outside the groove; and
in the subsequent step of etching, the outer edge portion is removed together with the groove portion of the bond wafer to form a terrace portion where the base wafer is exposed at the outer peripheral portion of the bonded wafer.
2. The method for manufacturing a bonded wafer according to claim 1 , wherein a width of the outer edge portion outside the groove of the bond wafer, which is formed through the grinding, is set not smaller than a width of a chamfered portion of the bond wafer and 2 mm or less.
3. The method for manufacturing a bonded wafer according to claim 1 , wherein a depth of the groove of the bond wafer formed through the grinding is determined so as to leave the bond wafer in the groove by a thickness of 5 μm or more and 80 μm or less.
4. The method for manufacturing a bonded wafer according to claim 2 , wherein a depth of the groove of the bond wafer formed through the grinding is determined so as to leave the bond wafer in the groove by a thickness of 5 μm or more and 80 μm or less.
5. The method for manufacturing a bonded wafer according to claim 1 , wherein the outer peripheral portion is etched with an acid or alkali.
6. The method for manufacturing a bonded wafer according to claim 2 , wherein the outer peripheral portion is etched with an acid or alkali.
7. The method for manufacturing a bonded wafer according to claim 3 , wherein the outer peripheral portion is etched with an acid or alkali.
8. The method for manufacturing a bonded wafer according to claim 4 , wherein the outer peripheral portion is etched with an acid or alkali.
9. The method for manufacturing a bonded wafer according to claim 1 , wherein the outer peripheral portion is ground by cutting into the bond wafer with a rotating round-bar-like grind stone having a rotational axis vertical to a main surface of the bonded wafer and an outer diameter not larger than a width of the groove in the step of grinding the outer peripheral portion.
10. The method for manufacturing a bonded wafer according to claim 8 , wherein the outer peripheral portion is ground by cutting into the bond wafer with a rotating round-bar-like grind stone having a rotational axis vertical to a main surface of the bonded wafer and an outer diameter not larger than a width of the groove in the step of grinding the outer peripheral portion.
11. The method for manufacturing a bonded wafer according to claim 1 , wherein the outer peripheral portion is ground by bringing a rotating disk-like grind stone that has a rotational axis parallel to a main surface of the bonded wafer and a thickness not larger than a width of the groove, into contact with the bond wafer from above in the step of grinding the outer peripheral portion.
12. The method for manufacturing a bonded wafer according to claim 8 , wherein the outer peripheral portion is ground by bringing a rotating disk-like grind stone that has a rotational axis parallel to a main surface of the bonded wafer and a thickness not larger than a width of the groove, into contact with the bond wafer from above in the step of grinding the outer peripheral portion.
13. The method for manufacturing a bonded wafer according to claim 1 , wherein the outer peripheral portion is ground such that at least one of an orientation flat portion and a notch portion is formed by cutting into the bond wafer with a rotating round-bar-like grind stone having a rotational axis vertical to a main surface of the bonded wafer and an outer diameter not larger than a width of the groove, and the other portions are formed by bringing a rotating disk-like grind stone that has a rotational axis parallel to a main surface of the bonded wafer and a thickness not larger than a width of the groove, into contact with the bond wafer from above, in the step of grinding the outer peripheral portion.
14. The method for manufacturing a bonded wafer according to claim 8 , wherein the outer peripheral portion is ground such that at least one of an orientation flat portion and a notch portion is formed by cutting into the bond wafer with a rotating round-bar-like grind stone having a rotational axis vertical to a main surface of the bonded wafer and an outer diameter not larger than a width of the groove, and the other portions are formed by bringing a rotating disk-like grind stone that has a rotational axis parallel to a main surface of the bonded wafer and a thickness not larger than a width of the groove, into contact with the bond wafer from above, in the step of grinding the outer peripheral portion.
15. The method for manufacturing a bonded wafer according to claim 9 , wherein the outer diameter of the round-bar-like grind stone is set to 5 mm or less.
16. The method for manufacturing a bonded wafer according to claim 10 , wherein the outer diameter of the round-bar-like grind stone is set to 5 mm or less.
17. The method for manufacturing a bonded wafer according to claim 13 , wherein the outer diameter of the round-bar-like grind stone is set to 5 mm or less.
18. The method for manufacturing a bonded wafer according to claim 14 , wherein the outer diameter of the round-bar-like grind stone is set to 5 mm or less.
19. The method for manufacturing a bonded wafer according to claim 1 , wherein etching is carried out immediately after the step of grinding the outer peripheral portion without encasing the wafer.
20. The method for manufacturing a bonded wafer according to claim 12 , wherein etching is carried out immediately after the step of grinding the outer peripheral portion without encasing the wafer.
21. The method for manufacturing a bonded wafer according to claim 16 , wherein etching is carried out immediately after the step of grinding the outer peripheral portion without encasing the wafer.
22. The method for manufacturing a bonded wafer according to claim 18 , wherein etching is carried out immediately after the step of grinding the outer peripheral portion without encasing the wafer.