Crystal structure orientation in semiconductor semi-finished products and semiconductor substrates for fissure reduction and method of setting same

1 . A monocrystalline semiconductor semi-finished product or monocrystalline semiconductor substrate of improved mechanical robustness against cleavage, the semiconductor semi-finished product or substrate having a central axis and a at least partially curved lateral surface parallel to said central axis, further comprising:

first and second front faces, wherein

the first front face is perpendicular to the central axis, and

said central axis is an axis of symmetry of a cylindrical surface defined by a curved part of said at least partially curved lateral surface,

characterized in that

a crystal structure of the monocrystalline semiconductor is a diamond structure, said crystal structure being oriented relative to the central axis and the at least partially curved lateral surface of the semiconductor semi-finished product or substrate with a predetermined orientation at which:

a first crystallographic axis, which is a crystallographic axis perpendicular to a set of first cleavage planes of the {111} family, makes a first tilt angle with a plane transverse to the central axis;

a second crystallographic axis, which is a crystallographic axis perpendicular to a set of second cleavage planes and to the first crystallographic axis, makes a second tilt angle with said plane transverse to the central axis so that each set of parallel cleavage planes that are symmetrically equivalent to either the first cleavage planes or to the second cleavage planes are inclined relative to the central axis by respective tilt angles; and

a reference lattice plane of the crystal structure, which is a plane of the {110} family that makes an angle of 90° with the first cleavages planes, is inclined with respect to the first front face by the first tilt angle in the direction of the first crystallographic axis and by the second tilt angle in the direction of the second crystallographic axis;

wherein the first crystallographic axis is the [111] axis or any of the crystallographic axes symmetrically equivalent to the [111] axis in the diamond structure,

wherein the first tilt angle and the second tilt angle are selected such that each set of first cleavage planes and each set of second cleavage planes of said crystal structure intersects the at least partially curved lateral surface along a line segment, which is parallel to the central axis, with at least a predetermined minimum number of parallel cleavage planes per unit length of the line segment, respectively, irrespective to a position of the line segment around an outer perimeter of the semiconductor semi-finished product or substrate, and

wherein said predetermined minimum number of parallel cleavage planes per unit length is at least 1000 planes per millimeter.

2 . The monocrystalline semiconductor semi-finished product or substrate of claim 1 , wherein

the selected first tilt angle is an estimated value based on an atomic distance between adjacent, first cleavage planes and on a radial force to actuate along said line segment during mechanical processing of the semiconductor semi-finished product or substrate, so as to yield a number of parallel, first cleavage planes intersecting the line segment per unit length at which the radial force per first cleavage plane is lower than a given cleavage threshold for the first cleavage planes; and/or

the selected second tilt angle is an estimated value based on an atomic distance between adjacent, second cleavage planes and on a radial force to actuate along said line segment during mechanical processing of the semiconductor semi-finished product or substrate, so as to yield a number of parallel, second cleavage planes intersecting the line segment per unit length at which the radial force per second cleavage plane is lower than a given cleavage threshold for the second cleavage planes.

3 . The monocrystalline semiconductor semi-finished product or substrate of claim 1 ,

wherein the first and second front faces are respectively perpendicular to the at least partially curved lateral surface, and/or the second front face is perpendicular to the central axis; and/or

the monocrystalline semiconductor is silicon.

4 . A method of producing the monocrystalline semiconductor semi-finished product or monocrystalline semiconductor substrate according to claim 1 , the method comprising:

performing a process of setting the predetermined orientation of the crystal structure relative to the central axis and the at least partially curved lateral surface to the predetermined orientation at which:

the first crystallographic axis perpendicular to the set of first cleavage planes makes the first tilt angle with the plane transverse to the central axis, and

the second crystallographic axis perpendicular to the set of second cleavage planes and to the first crystallographic axis makes the second tilt angle with said plane transverse to the central axis so that each set of parallel cleavage planes that are symmetrically equivalent to either the first cleavage planes or to the second cleavage planes are inclined relative to the central axis by respective tilt angles;

wherein the first tilt angle and the second tilt angle are selected such that each set of first cleavage planes and each set of second cleavage planes of said crystal structure intersects said at least partially curved lateral surface along the line segment, which is parallel to the central axis, with at least the predetermined minimum number of parallel cleavage planes per unit length of the line segment, respectively, and irrespective to the position of the line segment around the outer perimeter of the semiconductor semi-finished product or substrate, and

wherein said predetermined minimum number of parallel cleavage planes per unit length is at least 1000 planes per millimeter.

5 . The method of claim 4 , wherein the monocrystalline semiconductor is silicon.

6 . The method of claim 4 , further comprising:

estimating said first tilt angle based on an atomic distance between the first cleavage planes normal to the first crystallographic axis, and/or

estimating said second tilt angle based on an atomic distance between the second cleavage planes normal to the second crystallographic axis so as to yield said at least predetermined minimum number of parallel cleavage planes per unit length.

7 . The method of claim 4 , wherein the process of setting said predetermined orientation of the crystal structure with respect to said central axis of the semiconductor semi-finished product includes:

spatially orienting the crystal structure with respect to an alignment axis such as to achieve said predetermined orientation of the crystal structure with respect to a plane transverse to said alignment axis; and

machining an external surface of the spatially oriented crystal structure with reference to said alignment axis to form at least one of:

the at least partially curved lateral surface that is substantially parallel to said alignment axis, and

at least one of the first and second front face surfaces is substantially orthogonal to the alignment axis;

wherein the alignment axis of the spatially oriented crystal structure is selected to be parallel to the central axis of the semiconductor semi-finished product.

8 . The method of claim 7 , wherein the process of spatially orienting the crystal structure with respect to the alignment axis includes:

aligning a principal crystallographic axis of the reference lattice plane along an alignment direction, the reference lattice plane being transverse to the sets of first and second cleavage planes, and

tilting the reference lattice plane in a first direction by the first tilt angle, the first direction corresponding to the first crystallographic axis normal to the set of first cleavage planes, so that the set of first cleavage planes becomes inclined by the first tilt angle relative to the alignment axis and the set of second cleavage planes remains parallel to the alignment axis.

9 . The method of claim 7 , wherein the process of spatially orienting the crystal structure with the predetermined orientation respect to the alignment axis further includes:

tilting the reference lattice plane in a second direction by the second tilt angle, the second direction corresponding to the second crystallographic axis, so that the set of second cleavage planes becomes inclined by the second tilt angle relative to the alignment axis.

10 . The method of claim 8 , wherein the process of spatially orienting the crystal structure with respect to the alignment axis includes:

aligning the principal crystallographic axis of the reference lattice plane along the alignment direction, the reference lattice plane being transverse to the set of first cleavage planes;

rotating the reference lattice plane about said alignment direction by a predetermined rotation angle in a clockwise direction or a counter-clockwise direction; and

tilting the rotated reference lattice plane by the first tilt angle in the first direction, the first direction corresponding to the first crystallographic axis of said set of first cleavage planes.