the present invention is described with reference to the attached figures , wherein like reference numerals are used throughout the figures to designate similar or equivalent elements . the figures are not drawn to scale and they are provided merely to illustrate the invention . several aspects of the invention are described below with reference to example applications for illustration . it should be understood that numerous specific details , relationships , and methods are set forth to provide a full understanding of the invention . one skilled in the relevant art , however , will readily recognize that the invention can be practiced without one or more of the specific details or with other methods . in other instances , well - known structures or operations are not shown in detail to avoid obscuring the invention . the present invention is not limited by the illustrated ordering of acts or events , as some acts may occur in different orders and / or concurrently with other acts or events . furthermore , not all illustrated acts or events are required to implement a methodology in accordance with the present invention . for the purpose of facilitating the reading of this disclosure , the term “ atomically sharp ” is understood to mean “ tapered in a conical configuration to an end consisting of at least a single atom .” the term “ critical dimension ” or “ cd ” is understood to mean a lateral dimension of a structure ; for examples , the cd of a gate in an mos transistor is a width of the gate material , and the cd of a via hole is an internal diameter of the via hole . the term “ diamond like carbon ” is understood to mean a conductive material composed substantially of carbon with a mechanical hardness higher than silicon or tungsten . fig1 a and fig1 b are views of an afm probe according to an embodiment of the instant invention . fig1 a is a side view of the probe ; fig1 b is a bottom view of the probe . afm probe ( 100 ) includes a probe shaft ( 102 ), a right tip ( 104 ) that is conically shaped , atomically sharp and angled downward approximately 45 degrees to the right of the probe shaft ( 102 ), and a left tip ( 106 ) that is also conically shaped , atomically sharp and angled downward approximately 45 degrees to the left of the probe shaft ( 102 ). both right tip ( 104 ) and left tip ( 106 ) extend beyond the radius of the probe shaft ( 102 ) several nanometers , as depicted in fig1 b . the probe is tilted between 2 and 10 degrees during a profile measurement of an intersection of a horizontal surface and a vertical surface , for example , an intersection of a gate sidewall with an ic substrate . a preferred downward angle ( 108 ) for each tip ( 104 , 106 ) is 45 degrees minus the tilt angle of 2 to 10 degrees . shaft ( 102 ) may be made of carbon nanotube material or other material . right tip ( 104 ) and left tip ( 106 ) may be made of diamond - like carbon , or other hard , conducting material . an advantage of using conically shaped , atomically sharp tips is that conically shaped , atomically sharp tips are more easily maintained in routine use than flared or rounded tips , because an atomically sharp tip may be cleaned and sharpened using field emission techniques without removing it from the afm , while flared or rounded tips cannot be maintained so . another advantage of the use of atomically sharp tips is that they can provide higher resolution profiles than rounded or flared tips . fig2 a and fig2 b depict an afm probe according to an embodiment of the instant invention during a cd and profile measurement of a mos transistor gate in an integrated circuit . fig2 a depicts the afm probe during a measurement of the right profile of the gate . fig2 b depicts the afm probe during a measurement of the left profile of the gate . referring to fig2 a , ic ( 208 ) includes a substrate ( 210 ) and a mos transistor gate ( 212 ). the region of intersection ( 214 ) of the gate ( 212 ) with the substrate ( 210 ) may have a radius of curvature less than 2 nanometers . afm probe ( 200 ) is tilted to the left by an angle ( 216 ) sufficient to prevent contact of the substrate ( 210 ) by the right tip ( 204 ), and to attain an orientation for measuring a right - side profile of gate ( 212 ) using the left tip ( 206 ). the atomically sharp property and downward angle of the left tip are advantageous because , when tilted as depicted in fig2 a , contact of only the left tip ( 206 ) with the integrated circuit ( 200 ) is ensured , and thus the left tip ( 206 ) can profile the intersection region ( 214 ) of the gate ( 212 ) with the substrate ( 210 ). the tilt angle ( 216 ) need not be known precisely to execute a profile measurement ; this is advantageous because measurement execution is facilitated . the atomically sharp tip ( 206 ) can provide a higher resolution lateral profile , known as line width roughness , of the gate ( 212 ) than a tip with a rounded shape . gates made of polycrystalline silicon typically have grain sizes of a few nanometers . probes with atomically sharp tips can produce profiles that accurately depict individual grains , which is not practical using probed with rounded tips . higher resolution profiles are advantageous for practitioners of integrated circuit fabrication . referring to fig2 b , afm probe ( 200 ) is tilted to the right by an angle ( 218 ) sufficient to prevent contact of the substrate ( 210 ) by the left tip ( 206 ), and to attain an orientation for measuring a left - side profile of gate ( 212 ) using the right tip ( 204 ). the atomically sharp property and downward angle of the right tip are advantageous because , when tilted as depicted in fig2 b , contact of only the right tip ( 204 ) with the integrated circuit ( 200 ) is ensured , and thus the right tip ( 204 ) can profile the intersection region ( 214 ) of the gate ( 212 ) with the substrate ( 210 ). the tilt angle ( 218 ) need not be known precisely to execute a profile measurement ; this is advantageous because measurement execution is facilitated . fig3 a and fig3 b depict an afm probe according to an embodiment of the instant invention during a cd and profile measurement of a photoresist structure on an integrated circuit . fig3 a depicts the afm probe during a measurement of the right profile of the photoresist structure . fig3 b depicts the afm probe during a measurement of the left profile of the photoresist structure . referring to fig3 a , ic ( 308 ) includes a substrate ( 310 ) and a photoresist structure ( 312 ). the region of intersection ( 314 ) of the photoresist structure ( 312 ) with the substrate ( 310 ) may have a radius of curvature less than 2 nanometers . afm probe ( 300 ) is tilted to the left by an angle ( 316 ) sufficient to prevent contact of the substrate ( 310 ) by the right tip ( 304 ), and to attain an orientation for measuring a right - side profile of photoresist structure ( 312 ) using the left tip ( 306 ). the atomically sharp property and downward angle of the left tip are advantageous because , when tilted as depicted in fig3 a , contact of only the left tip ( 306 ) with the integrated circuit ( 300 ) is ensured , and thus the left tip ( 306 ) can profile the intersection region ( 314 ) of the photoresist feature ( 312 ) with the substrate ( 310 ). the tilt angle ( 316 ) is not critical , and need not be known precisely to execute a profile measurement ; this is advantageous because measurement execution is facilitated . referring to fig3 b , afm probe ( 300 ) is tilted to the right by an angle ( 318 ) sufficient to prevent contact of the substrate ( 310 ) by the left tip ( 306 ), and to attain an orientation for measuring a left - side profile of photoresist structure ( 312 ) using the right tip ( 304 ). the atomically sharp property and downward angle of the right tip are advantageous because , when tilted as depicted in fig3 b , contact of only the right tip ( 304 ) with the integrated circuit ( 300 ) is ensured , and thus the right tip ( 304 ) can profile the intersection region ( 314 ) of the photoresist structure ( 312 ) with the substrate ( 310 ). the tilt angle ( 318 ) is not critical , and need not be known precisely to execute a profile measurement ; this is advantageous because measurement execution is facilitated . fig4 depicts an afm probe according to an embodiment of the instant invention during a cd and profile measurement of an interconnect via hole in an integrated circuit . integrated circuit ( 408 ) includes inter - level dielectric layer ( 410 ), typically formed of low - k material , in which an interconnect via hole ( 412 ), which may be less than 100 nanometers in diameter , has been formed . afm probe ( 400 ) embodying the instant invention is positioned in via hole ( 412 ) so as to contact a surface of the via hole ( 412 ) with left probe tip ( 406 ). construction of the afm probe by attaching atomically sharp tips ( 404 , 406 ) to a shaft ( 402 ) results in an afm probe that is small enough to fit inside an interconnect via hole . this is advantageous because afm probes currently in use are larger than via holes in many integrated circuits , and hence cannot be used to profile interiors of those via holes or measure their cd . fig5 depicts an afm probe according to an embodiment of the instant invention during a cd and profile measurement of a contact hole in an integrated circuit . integrated circuit ( 508 ) includes substrate ( 510 ) and pre - metal dielectric layer ( 512 ), typically formed of silicon dioxide , in which a contact hole ( 514 ), which may be less than 100 nanometers in diameter , has been formed . afm probe ( 500 ) embodying the instant invention is positioned in contact hole ( 514 ) so as to contact a surface of the contact hole ( 514 ) with left probe tip ( 506 ). construction of the afm probe by attaching atomically sharp tips ( 504 , 506 ) to a shaft ( 502 ) results in an afm probe that is small enough to fit inside a contact hole . this is advantageous because afm probes currently in use are larger than contact holes in many integrated circuits , and hence cannot be used to profile interiors of those contact holes or measure their cd . fig6 depicts an afm probe according to an embodiment of the instant invention during a cd and profile measurement of an interconnect trench in an integrated circuit . integrated circuit ( 608 ) includes intra - level dielectric layer ( 610 ), typically formed of low - k dielectric material , in which an interconnect trench ( 612 ), which may be less than 100 nanometers wide , has been formed . afm probe ( 600 ) embodying the instant invention is positioned in trench ( 612 ) so as to contact a sidewall of the trench ( 612 ) with left probe tip ( 606 ). construction of the afm probe by attaching atomically sharp tips ( 604 , 606 ) to a shaft ( 602 ) results in an afm probe that is small enough to fit inside a typical interconnect trench . this is advantageous because afm probes currently in use are larger than interconnect trenches in many integrated circuits , and hence cannot be used to profile interiors of those trenches or measure their cd . in another embodiment , the afm probe ( 600 ) may be tilted to obtain profile measurements of intersections of trench sidewalls with trench bottoms . fig7 is a top view of a contact hole in an ic during a profile measurement using an afm probe according to an embodiment of the instant invention , with a flared tip probe for comparison purposes . contact hole ( 700 ) in a pre - metal dielectric layer ( 702 ) has features a few nanometers in size on its sidewall ( 704 ). an afm probe according to an embodiment of the instant invention ( 706 ) has a probe tip ( 708 ) with a radius less then 1 nanometer , and can resolve features in the hole sidewall ( 704 ) down to approximately 1 nanometer in size . a flared probe ( 710 ) typically has a radius greater than 20 nanometers , and cannot resolve features smaller than 20 nanometers in the hole sidewall ( 704 ). the use of an afm probe according to an embodiment of the instant invention is advantageous because it provides the user with more detailed information regarding the surface profile of contact holes and via holes than measurements with other afm probes . fig8 a through 8e are cross - sections of an ic during fabrication encompassing afm measurements using an embodiment of the instant invention . fig8 a depicts the ic during an afm profile measurement of a photoresist structure in an mos transistor gate pattern . fig8 b depicts the ic during an afm profile measurement of an mos transistor gate . fig8 c depicts the ic during an afm profile measurement of a contact hole . fig8 d depicts the ic during an afm profile measurement of a metal interconnect trench . fig8 e depicts the ic during an afm profile measurement of a via hole . referring to fig8 a , ic ( 800 ) includes a substrate ( 802 ), typically p - type silicon , an n - type region formed in the substrate , known as an n - well ( 804 ), a p - type region formed in the substrate , known as a p - well ( 806 ), and regions of field oxide ( 808 ), typically silicon dioxide , formed in the substrate by local oxidation of silicon ( locos ) or shallow trench isolation ( sti ). a gate dielectric layer ( 810 ), typically silicon dioxide , silicon dioxide with nitrogen , silicon oxy - nitride , or hafnium oxide , is formed on a top surface of the n - well ( 804 ), p - well ( 806 ) and field oxide ( 808 ). a layer of gate material ( 812 ), typically polycrystalline silicon , is formed on a top surface of the gate dielectric layer ( 810 ). a photoresist pattern including a p - channel mos transistor gate photoresist structure ( 814 ) and an n - channel mos transistor gate photoresist structure ( 816 ) are formed on a top surface of the gate material layer ( 812 ). an afm probe according to an embodiment of the instant invention ( 818 ) is positioned to perform a profile measurement of the p - channel mos transistor gate structure ( 814 ). the left tip ( 820 ) of the afm probe ( 818 ) is in contact with the p - channel mos transistor gate structure ( 814 ). the afm probe ( 818 ) may be tilted to the left of vertical , as discussed in reference to fig3 a above . referring to fig8 b , a p - channel mos transistor gate ( 822 ) and an n - channel mos transistor gate ( 824 ) are formed on the top surface of the gate dielectric layer ( 810 ). the afm probe ( 818 ) is positioned to perform a profile measurement of the p - channel mos transistor gate ( 822 ). the left tip ( 820 ) of the afm probe ( 818 ) is in contact with the p - channel mos transistor gate ( 822 ). the afm probe ( 818 ) may be tilted to the left of vertical , as discussed in reference to fig3 a above . referring to fig8 c , pmos sidewall spacers ( 826 ), typically layers of silicon dioxide and silicon nitride , are formed abutting to the p - channel mos transistor gate ( 822 ), and nmos sidewall spacers ( 828 ), also typically layers of silicon dioxide and silicon nitride , are formed abutting to the n - channel mos transistor gate ( 824 ). p - type source and drain regions ( 830 ) are formed in the n - well ( 804 ) adjacent to the p - channel mos transistor gate ( 822 ). n - type source and drain regions ( 832 ) are formed in the p - well ( 806 ) adjacent to the n - channel mos transistor gate ( 824 ). a pre - metal dielectric ( pmd ) layer ( 834 ), typically silicon dioxide , is formed on a top surface of the gates ( 822 , 824 ), the sidewall spacers ( 826 , 828 ) and the p - type source and drain regions ( 830 ), the n - type source and drain regions ( 832 ) and field oxide ( 808 ). contact holes ( 836 ) are formed in the pmd layer ( 832 ). the afm probe ( 818 ) is positioned to perform a profile measurement of a contact hole ( 836 ). the left tip ( 820 ) of the afm probe ( 818 ) is in contact with pmd dielectric layer material at the contact hole sidewall . referring to fig8 d , contacts ( 838 ), typically tungsten , are formed in the pmd dielectric layer ( 834 ). an intra - level dielectric layer ( 840 ), typically low - k dielectric material such as organo - silicate glass , is formed on a top surface of the pmd layer ( 834 ) and the contacts ( 838 ). trenches ( 842 ) for metal interconnect lines have been etched in the intra - level dielectric layer ( 840 ). the afm probe ( 818 ) is positioned to perform a profile measurement of a metal interconnect line trench ( 842 ). the left tip ( 820 ) of the afm probe ( 818 ) is in contact with intra - level dielectric layer material at the trench sidewall . referring to fig8 e , metal interconnect lines ( 844 ) are formed in the intra - level dielectric layer ( 840 ). an inter - level dielectric layer ( 846 ), also typically low - k dielectric material such as organo - silicate glass , is formed on a top surface of the metal interconnect lines ( 842 ) and the intra - level dielectric layer ( 840 ). via holes ( 848 ) are etched in the inter - level dielectric layer ( 844 ). the afm probe ( 818 ) is positioned to perform a profile measurement of a via hole ( 848 ). the left tip ( 820 ) of the afm probe ( 818 ) is in contact with inter - level dielectric layer material at the via sidewall .