Wafer processing method
A wafer processing method including a mask forming step of forming a mask for covering a region corresponding to each device on a functional layer formed on the front side of a substrate constituting a wafer, a groove forming step of spraying a fluid containing abrasive grains against the front side of the wafer to thereby form a groove for dividing the functional layer along each street, and an etching step of performing dry etching from the front side of the wafer to thereby form an etched groove along each street. Accordingly, it is possible to prevent that the functional layer may be separated to cause damage to each device. Furthermore, a wide area of the wafer can be processed at a time, so that the productivity can be improved.
1. A wafer processing method for dividing a wafer into a plurality of devices along a plurality of streets formed on a front side of said wafer, said wafer including a substrate and a functional layer formed on a front side of said substrate, said devices being formed from said functional layer and partitioned by said streets, wherein areas corresponding to said streets include metal regions thereon, said wafer processing method comprising:
a mask forming step of forming a mask for covering a region corresponding to each device on said functional layer of said wafer;
a groove forming step of spraying a fluid containing abrasive grains against the front side of said wafer after performing said mask forming step, thereby forming a groove for dividing said functional layer along each street, wherein said groove is formed by removal of a portion of said functional layer, including removal of portions of said metal regions, by spraying said fluid containing abrasive grains; and
an etching step of performing dry etching along each street from the front side of said wafer after performing said groove forming step, thereby forming an etched groove on said substrate along each street.
2. The wafer processing method according to claim 1 , wherein said etched groove formed in said etching step has a depth not reaching the back side of said wafer; and
said wafer processing method further comprises a thickness reducing step of grinding a back side of said wafer after performing said etching step, thereby reducing the thickness of said wafer to a predetermined thickness.
3. The wafer processing method according to claim 1 , further comprising a mask removing step of removing said mask from said functional layer after performing said etching step.
4. The wafer processing method according to claim 1 , wherein the functional layer comprises a plurality of stacked low-k films and a passivation film.
5. The wafer processing method according to claim 4 , wherein said low-k film comprises an inorganic film, a polymer film, and an organic film.
6. The wafer processing method according to claim 4 , wherein the passivation film comprises a film of a material selected from the group consisting of S i O 2 , S i O, S i N, and S i ON.