US 8,241,961 B2 · Method for manufacturing hetero-bonded wafer

Abstract

A method for manufacturing a hetero-bonded wafer having a large mismatch of thermal expansion coefficient comprises forming a wafer bonding means and an electrical interconnection means on at least one bonding surface of two wafers to be bonded with each other, forming grooves in the bonding surface of one wafer along dicing lines with an interval between the grooves being equal to or an even multiple of a die width, bonding the two wafers at a temperature less than 200° C., thinning a back side of the grooved wafer such that at least a portion of the grooves is exposed, and rebonding the bonded wafer pair at an elevated temperature higher than the first bonding temperature. The method for manufacturing a hetero-bonded wafer can avoid wafer level bow/warp and also reduce debonding and cracking in individual segments induced by thermal stress due to a mismatch of thermal expansion coefficient. Embodiments of the method are useful for wafer level packaging and the fabrication of hybrid devices by heterogeneous wafer bonding.

Claims23

Dependent claims

A method for manufacturing a hetero-bonded wafer comprising:

(a) providing a first wafer and a second wafer having substantially different thermal expansion coefficients from one another;
(b) forming bonding means and electrical interconnection means on at least one bonding surface of the first wafer and the second wafer;
(c) forming grooves having a depth shallower than a thickness of the first wafer in the bonding surface along dicing lines of the first wafer, thereby dividing the bonding surface of the first wafer into a plurality of small segments having a size defined by the grooves;
(d) aligning and bonding the first wafer and the second wafer together as a bonded wafer pair at a first bonding temperature of less than 200° C. to avoid arising thermal stress while providing intermediate bonding of the bonded wafer pair;
(e) thinning a back side of the bonded first wafer such that at least a portion of the grooves are exposed, thereby fragmenting the bonded first wafer into a plurality of small segments while the small segments remain bonded to the second wafer;
and
(f) rebonding the bonded wafer pair at an elevated temperature of at least greater than the first bonding temperature.

4 more elements

Dependencies are inferred from the claim text.

Method for manufacturing hetero-bonded wafer

Life of this patent

Method for manufacturing hetero-bonded wafer

Life of this patent

Abstract

Claims23