METHODS FOR PROCESSING A SEMICONDUCTOR WAFER, A SEMICONDUCTOR WAFER AND A SEMICONDUCTOR DEVICE
A semiconductor wafer, comprising multiple active areas suitable for providing semiconductor devices or circuits. Inactive areas separate the active areas from each other. The wafer has a stressed layer with a first surface, and another layer which is in contact with the stressed layer along a second surface of the stressed layer, opposite to the first surface. Multiple trench lines, extend in parallel to the first surface of the stressed layer in an inactive area and have a depth less than the thickness of the semiconductor wafer.
1 . A method for processing a semiconductor wafer, comprising:
providing the semiconductor wafer, the semiconductor wafer having a curvature in at least one direction;
reducing the curvature, said reducing comprising:
providing in inactive areas of the semiconductor wafer multiple trench lines extending at least partially in a stressed layer of the semiconductor wafer and in parallel with the surface of the stressed layer, the multiple trench lines having a depth less than the thickness of the semiconductor wafer,
the stressed layer being a III-nitride layer,
the trenchlines extending from the top-surface of the stressed layer into the stressed layer to a depth d1 which is less than the thickness d2 of the stressed layer.
2 . A method as claimed in claim 1 , comprising: providing the semiconductor wafer with a semiconductor device in an active area outside the inactive area.
3 . A method as claimed in claim 2 , comprising providing multiple semiconductor devices or circuits in respective active areas, and wherein the trench lines are separated by at least one active area.
4 . A method as claimed in claim 1 , wherein the multiple trench lines are separated at least 1 mm from each other.
5 . (canceled)
6 . (canceled)
7 . A method as claimed in claim 1 , wherein the stressed layer is compressively stressed.
8 . A method as claimed in claim 1 , comprising further processing said semiconductor wafer, and wherein at least some material is provided in said trench lines in at least some stages of said further processing.
9 . A method for processing a semiconductor wafer, comprising:
providing a semiconductor wafer processed with a method of claim 1 ,
dicing the semiconductor wafer into separate dies.
10 . A method as claimed in claim 9 , comprising: subjecting at least one of the separate die to further processing.
11 . A semiconductor wafer, comprising:
multiple active areas suitable for providing semiconductor devices or circuits;
inactive areas which separate the active areas from each other;
a stressed layer with a first surface; and
another layer which is in contact with the stressed layer along a second surface of the stressed layer, opposite to the first surface;
multiple trench lines, each extending parallel to the first surface of the stressed layer in an inactive area and having a depth less than the thickness of the semiconductor wafer,
the stressed layer being a III-nitride layer,
the trenchlines extending from the to surface of the stressed layer into the stressed layer to a depth d1 which is less than the thickness d2 of the stressed.
12 . A wafer as claimed in claim 1 , comprising semiconductor devices or circuits provided in active areas.
13 . A semiconductor device, comprising a die singulated out of a semiconductor wafer as claimed in claim 9 , on which die at least one trench-line of said semiconductor wafer is detectable.
14 . A method as claimed in claim 1 , wherein the depth d 1 of the trenchlines is less than or equal to half the thickness d 2 of the stressed layer.
15 . A method as claimed in claim 1 , comprising, after formation of the trenchlines and the associated reduction of the curvature, forming an electronic circuit on the substrate.
16 . A method as claimed in claim 1 , wherein the stressed layer is a GaN heteroepitaxial layer grown on a Si substrate.
17 . A method as claimed in claim 1 , the semiconductor wafer comprising one or more intermediate layers on a substrate.
18 . A method as claimed in claim 17 , the one or more intermediate layers comprising a seed layer.
19 . A method as claimed in claim 18 , the seed layer being formed from a suitable nitride of a III-V semiconductor material selected from the group of AlN, aluminium gallium nitride, AlInN or any combination of AlGaINN.
20 . A method as claimed in claim 17 , the one or more intermediate layers comprising a stack of a seed layer and one or more transitional layers.