Patent ID: 7829446

Claim:
A method for dividing a wafer into a plurality of chips, the method comprising: bonding a first substrate having reservoir sections and piezoelectric retaining sections formed therein to a second substrate; providing recesses and channels in the second substrate simultaneously in an etching process, the recesses being formed at positions along boundaries between regions to become individual chips and the channels being formed inside the regions to become individual chips, such that the recesses and channels extend through an entire width of the second substrate; providing fragile portions having a predetermined width inside the first substrate at positions along the boundaries by irradiation of a non-bonded surface of the first substrate opposite to the surface bonded to the second substrate with a laser beam whose condensing point is placed inside the first substrate, the fragile portions including a connected portion at the non-bonded surface of the first substrate; and dividing the bonded first and second substrates at the fragile portions into the individual chips by applying an external force to the bonded first and second substrates.