Method and Apparatus for Producing Uniform, Isotropic Stresses in a Sputtered Film

1 . A method for depositing a film on a substrate, comprising the steps of:

depositing successive layers of film on said substrate at any of successive different discrete deposition angles of rotation of said substrate and/or of said deposition source about a normal axis of said substrate;

providing a substantially identical amount of deposition from each different deposition angle as for each other deposition angle;

wherein said overall deposited film behaves substantially isotropically in properties in all directions parallel to said substrate and at different angles of rotation about said normal axis.

2 . The method of claim 1 , further comprising the step of:

reducing the thickness of successive layers of said film on the order of a property projection distance within a depositing material;

wherein said property projection distance comprises a distance at which a fluctuation in a relevant film property from point to point through said film's thickness becomes too small to affect overall properties of said film when averaged through said film's thickness; and

wherein said fluctuation is caused by layering.

3 . The method of claim 2 , wherein said property projection distance is within a minimum of one atomic diameter of said depositing material to a maximum of ten atomic diameters for stress and strain, and a maximum of one magnetic domain diameter for magnetic properties.

4 . The method of claim 1 , further comprising the step of:

moving each substrate past a same one or more sources of depositing material in a planetary manner;

wherein each time said substrate passes by one of said sources of depositing material as said substrate executes a planet orbit, said substrate is rotated about said substrate's normal axis with respect to the planet carrier such that it maintains a constant rotational orientation with respect to a stationary point and said depositing material source by which it is passing.

5 . The method of claim 4 , wherein said substrate is rotated 360/n degrees with respect to the planet carrier plate each time it passes by one of said depositing material sources, wherein n is an integer larger than 2 and equal to the number of deposition sources.

6 . The method of claim 4 , further comprising the steps of:

providing four depositing material sources arranged about a circle; and

positioning a relevant anisotropic property of each said depositing material source 90 degrees with respect to that of a previous depositing material source;

wherein each substrate maintains a fixed rotational orientation about its normal axis as said substrate orbits, as measured from a stationary point;

wherein said film is deposited in layers having an anisotropy rotated 90 degrees for each successive layer.

7 . The method of claim 4 , wherein said source of depositing material exhibits two-fold symmetry in a relevant anisotropic property of said depositing material source.

8 . The method of claim 7 , wherein a 270 degree rotation of said substrate is equivalent to a 90 degree rotation of said substrate with respect to said anisotropy in said relevant property of said film layer.

9 . The method of claim 7 , further comprising the step of:

providing two depositing material sources;

wherein each depositing material source has two-fold symmetry;

wherein said depositing material sources are disposed relative to one another such that a relevant anisotropic property of said depositing material source is rotated 90 degrees with respect to a previous depositing material source;

wherein each substrate maintains a fixed rotational orientation about its normal axis as it orbits, as measured from a stationary point; and

wherein said film is deposited in layers having an anisotropy rotated 90 degrees for each successive layer.

10 . The method of claim 7 , wherein said sources of depositing material comprise linear magnetron sputtering targets from which said depositing material emanates in a pattern which approximates a rectangle having rounded corners.

11 . The method of claim 10 , wherein a distance along a substrate normal axis and between a substrate surface and a target surface from which depositing material emanates is sufficiently smaller than a distance between material as it emanates from an end of said rectangular emanation pattern and a nearest edge of said substrate such that a relevant property of said film is sufficiently uniform along said substrate from a center of said substrate to said substrate's edge.

12 . The method of claim 11 , further comprising the step of:

making film stress along directions parallel to said substrate sufficiently uniform across said substrate by making a distance along a substrate normal axis and between a substrate surface and a target surface from which depositing material emanates sufficiently small, as compared to a distance between material as it emanates from an end of said rectangular emanation pattern and the nearest edge of the substrate.

13 . The method of claim 11 , wherein a ratio of distance along a substrate normal axis and between a substrate surface and a target surface from which depositing material emanates to a distance between material as it emanates from an end of said rectangular emanation pattern and a nearest edge of said substrate is ¼ or less.

14 . A method for depositing a film on a substrate, comprising the steps of:

symmetrically disposing at least one deposition source at any of successive different deposition angles of rotation of said substrate and of said deposition source about a normal axis of said substrate; and

depositing successive layers of film on said substrate to achieve high levels of stress in said films, wherein said stress is both isotropic in a film plane and uniform over large areas of a substrate surface.

15 . The method of claim 14 , wherein said depositing step comprises:

providing a monatomic-layer-scale deposition thickness per pass over a deposition source using close-spaced magnetron sputtering from long, substantially rectangular targets or sources of deposition material;

wherein effects on film stress caused by periodic fluctuations in any of deposition incident angle, ion bombardment flux, and substrate azimuthal orientation are minimized.

16 . The method of claim 14 , further comprising the step of:

rotating said substrate by substantially 90 degrees between successive passes to laminate said film;

wherein X-Y anisotropy in a film plane is eliminated.

17 . The method of claim 14 , further comprising the step of:

using magnetron targets that are longer, when compared to a substrate diameter, than is needed for uniform film thickness;

wherein uniform film stress along a long axis of said target is achieved.

18 . The method of claim 14 , further comprising the step of:

providing a drive mechanism comprising a peripheral chain arranged around a ring of substrates, and a chain extending from one substrate to a fixed central sprocket, to impart high speed, planetary motion to said substrate.

19 . An apparatus for depositing a film on a substrate, comprising:

a target for depositing successive layers of film on said substrate at any of successive different discrete deposition angles of rotation of said substrate and/or of said deposition source about a normal axis of said substrate;

means for symmetrically disposing a collection of said successive different discrete deposition angles used for an overall deposited film about said normal axis; and

means for providing a substantially identical amount of deposition from each different deposition angle as for each other deposition angle;

wherein said overall deposited film behaves substantially isotropically in properties in all directions parallel to said substrate and at different angles of rotation about said normal axis.

20 . The apparatus of claim 19 , further comprising:

means for reducing the thickness of successive layers of said film on the order of a property projection distance within a depositing material;

wherein said property projection distance comprises a distance at which a fluctuation in a relevant film property from point to point through said film's thickness becomes too small to affect overall properties of said film when averaged through said film's thickness; and

wherein said fluctuation is caused by layering.

21 . The apparatus of claim 20 , wherein said property projection distance is within a minimum of one atomic diameter of said depositing material to a maximum of ten atomic diameters for stress and strain, and a maximum of one magnetic domain diameter for magnetic properties.

22 . The apparatus of claim 19 , further comprising:

a drive for moving each substrate past a same one or more sources of depositing material in a planetary manner;

wherein each time said substrate passes by one of said sources of depositing material as said substrate executes a planet orbit, said substrate has been rotated about said substrate's normal axis with respect to the planet carrier such that it maintains a constant rotational orientation with respect to a stationary point and to said depositing material source by which it is passing.

23 . The apparatus of claim 22 , wherein said substrate is rotated 360/n degrees with respect to the planet carrier plate each time it passes by one of said depositing material sources, wherein n is an integer larger than 2 and equal to the number of deposition sources.

24 . The apparatus of claim 22 , further comprising:

four depositing material sources arranged about a circle; and

means for positioning a relevant anisotropic property of each said depositing material source 90 degrees with respect to that of a previous depositing material source;

wherein each substrate maintains a fixed rotational orientation about its normal axis as said substrate orbits, as measured from a stationary point;

wherein said film is deposited in layers having an anisotropy rotated 90 degrees for each successive layer.

25 . The apparatus of claim 22 , wherein said source of depositing material exhibits two-fold symmetry in a relevant anisotropic property of said depositing material.

26 . The apparatus of claim 25 , wherein a 270 degree rotation of said substrate is equivalent to a 90 degree rotation of said substrate with respect to said anisotropy in said relevant property of said film layer.

27 . The apparatus of claim 25 , further comprising:

two depositing material sources;

wherein each depositing material source has two-fold symmetry;

wherein said depositing material sources are disposed relative to one another such that a relevant anisotropic property of said depositing material source is rotated 90 degrees with respect to a previous depositing material source;

wherein each substrate maintains a fixed rotational orientation about its normal axis as it orbits, as measured from a stationary point; and

wherein said film is deposited in layers having an anisotropy rotated 90 degrees for each successive layer.

28 . The apparatus of claim 25 , wherein said sources of depositing material comprise linear magnetron sputtering targets from said depositing material emanates in a pattern which approximates a rectangle having rounded corners.

29 . The apparatus of claim 28 , wherein a distance along a substrate normal axis and between a substrate surface and a target surface from which depositing material emanates is sufficiently smaller than a distance between material as it emanates from an end of said rectangular emanation pattern and a nearest edge of said substrate such that a relevant property of said film is sufficiently uniform along said substrate from a center of said substrate to said substrate's edge.

30 . The apparatus of claim 29 , further comprising:

means for making film stress along directions parallel to said substrate sufficiently uniform across said substrate by making a distance along a substrate normal axis and between a substrate surface and a target surface from which depositing material emanates sufficiently small, as compared to a distance between material as it emanates from an end of said rectangular emanation pattern and the nearest edge of the substrate.

31 . The apparatus of claim 29 , wherein a ratio of distance along a substrate normal axis and between a substrate surface and a target surface from which depositing material emanates to a distance between material as it emanates from an end of said rectangular emanation pattern and a nearest edge of said substrate is ¼ or less.

32 . An apparatus for depositing a film on a substrate, comprising:

means for symmetrically disposing at least one deposition source at any of successive different deposition angles of rotation of said substrate and of said deposition source about a normal axis of said substrate; and

a target for depositing successive layers of film on said substrate to achieve high levels of stress in said films, wherein said stress is both isotropic in a film plane and uniform over large areas of a substrate surface.

33 . The apparatus of claim 32 , wherein said target comprises:

means for providing a monatomic-layer-scale deposition thickness per pass over a target using close-spaced magnetron sputtering from long, substantially rectangular targets;

wherein effects on film stress caused by periodic fluctuations in any of deposition incident angle, ion bombardment flux, and substrate azimuthal orientation are minimized.

34 . The apparatus of claim 32 , further comprising:

a drive for rotating said substrate by substantially 90 degrees between successive passes to laminate said film;

wherein X-Y anisotropy in a film plane is eliminated.

35 . The apparatus of claim 32 , further comprising:

one or more magnetron targets that are longer, when compared to a substrate diameter, than is needed for uniform film thickness;

wherein uniform film stress along a long axis of said target is achieved.

36 . The method of claim 32 , further comprising:

a drive mechanism comprising a peripheral chain arranged around a ring of substrates, and a chain extending from one substrate to a fixed central sprocket, to impart high speed, planetary motion to said substrate.

37 . A drive mechanism, comprising:

a fixed central, driven sprocket;

a peripheral chain arranged around a ring of substrates; and a chain extending from one substrate to said fixed central sprocket, to impart high speed, planetary motion to said substrate.

38 . A substrate having a film deposited thereon in accordance with the process of claim 1.