Using a double-cut for mechanical protection of a wafer-level chip scale package (wlcsp)

A method for assembling a wafer level chip scale processed (WLCSP) wafer, the wafer having a front-side surface and a back-side surface, a plurality of device die, having electrical contacts, on the front-side surface, the method comprising:

• mounting the wafer onto a grinding foil;
• back-grinding, to a thickness, the back-side surface the wafer;
• mounting the wafer onto a sawing foil on the back-side surface;
• sawing the WLCSP wafer in saw lanes of the plurality of device die on the front-side surface, the sawing occurring with a blade of a first kerf and to a first depth of about 50% the back-ground wafer thickness;
• again sawing the WLCSP along the saw lanes of the plurality of device die, the sawing occurring with a blade of a second kerf, the second kerf narrower than the first kerf, and sawing to a depth of about 90% to about 95% thickness of the back-ground wafer thickness;
• stretching the sawing foil so as to cleave apart the wafer and space apart device die, now having expanded saw lanes , resulting in vertical faces having overhangs thereon;
• on the front-side of the wafer, re-mounting the wafer onto molding foil and removing the sawing foil;
• enveloping the device die in the molding compound on the back-side surfaces and vertical faces of the spaced-apart device die, the molding compound of a thickness on the back-side surface and another thickness on the vertical faces, the overhangs providing enhanced anchoring of the molding compound;
• removing the molding foil;
• re-mounting the molded WLCSP wafer on its back-side surface, onto a sawing foil;
• and
• sawing the molded WLCSP wafer on the front-side surface in the expanded saw lanes of the plurality of device die so as to separate the molded wafer into individual device die having protective molding thereon.

A semiconductor device , with an active device having a front-side surface and a backside surface, the semiconductor device of an overall thickness, comprising:

• an active device with circuitry defined on the front-side surface, the front-side surface having an area;
• wherein in the back-side of the active device has recesses of a partial depth of the active device thickness and a width of about the partial depth, the recesses surrounding the active device at vertical edges;
• a protective layer of a thickness on to the backside surface of the active device, the protective material having an area greater than the first area and having a stand-off distance;
• wherein, the vertical edges have the protective layer filling the recesses flush with the vertical edges;
• and
• wherein a stand-off distance of the protective material is a function of the semiconductor device thickness and the tangent of an angle (θ) of tooling impact upon a vertical face the semiconductor device.