Method of ion implantation

Claim 1

A method of implanting impurity ions to form an impurity profile having varied depths in a wafer having a major surface, a desired impurity profile on the surface having at least three or continuous separate thicknesses obtained by a single ion implantation, comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern having a desired thickness relative to said impurity profile with a material having at least a single layer whose absorbency of ions changes depending upon the thickness thereof, said desired thickness varying along the length of said ion beam absorber pattern, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer to form source/drain regions, removing said ion beam absorber pattern at least in regions having a thickness greater than zero and in which ions have been implanted, and after the step of removing, forming a gate electrode between said source/drain regions on said major surface with a gate insulation film therebetween.

Claim 2

A method of implanting impurity ions to form an impurity profile having varied depths in a wafer having a major surface, a desired impurity profile on the surface having at least three or continuous separate thicknesses obtained by a single ion implantation, comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern having a desired thickness relative to said impurity profile with a material having at least a single layer whose absorbency of ions changes depending upon the thickness thereof, said desired thickness varying along the length of said ion beam absorber pattern, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer to form source/drain regions, removing said ion beam absorber pattern at least in regions having a thickness greater than zero and in which ions have been implanted, and after the step of removing, forming a gate electrode between said source/drain regions on said major surface with a gate insulation film therebetween.

Claim 12

A method of implanting impurity ions to form an impurity profile having varied depths in a wafer having a major surface, comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern from a single-layer material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, the absorbency of ions by said single-layer material depending upon said varying thickness, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer to form source/drain regions, removing said ion beam absorber pattern, and after the step of removing, forming a gate electrode between said source/drain regions on said major surface with a gate insulation film therebetween, wherein said step of forming said ion beam absorber pattern comprises the steps of forming an X-ray sensitive resist to be said ion beam absorber pattern on the whole major surface of said wafer, X-ray exposing said X-ray sensitive resist by employing an X-ray exposure pattern mask relative to the shape of said ion beam absorber pattern by developing said X-ray exposed X-ray sensitive resist.

Claim 13

A method of implanting impurity ions to form an impurity profile having varied depths in a wafer having a major surface, comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern from a single-layer material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, the absorbency of ions by said single-layer material depending upon said varying thickness, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer to form source/drain regions, removing said ion beam absorber pattern, and after the step of removing, forming a gate electrode between said source/drain regions on said major surface with a gate insulation film therebetween, wherein said step of forming said ion beam absorber pattern comprises the steps of forming an X-ray sensitive resist to be said ion beam absorber pattern on the whole major surface of said wafer, X-ray exposing said X-ray sensitive resist by employing an X-ray exposure pattern mask relative to the shape of said ion beam absorber pattern by developing said X-ray exposed X-ray sensitive resist.

Claim 15

A method of implanting impurity ions to form an impurity profile having varied depths in a wafer having a major surface, comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern from a single-layer material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, the absorbency of ions by said single-layer material depending upon said varying thickness, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer to form source/drain regions, removing said ion beam absorber pattern, and after the step of removing, forming a gate electrode between said source/drain regions on said major surface with a gate insulation film therebetween, wherein said step of forming said ion beam absorber pattern comprises the steps of: forming an FIB sensitive resist on the whole major surface of said wafer, FIB-exposing said FIB sensitive resist so as to allow said FIB sensitive resist to have a varying thickness corresponding to said ion beam absorber pattern, and forming a desired ion beam absorber pattern by developing said FIB-exposed FIB sensitive resist.

Claim 16

A method of implanting impurity ions to form an impurity profile having varied depths in a wafer having a major surface, comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern from a single-layer material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, the absorbency of ions by said single-layer material depending upon said varying thickness, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer to form source/drain regions, removing said ion beam absorber pattern, and after the step of removing, forming a gate electrode between said source/drain regions on said major surface with a gate insulation film therebetween, wherein said step of forming said ion beam absorber pattern comprises the steps of: forming an FIB sensitive resist on the whole major surface of said wafer, FIB-exposing said FIB sensitive resist so as to allow said FIB sensitive resist to have a varying thickness corresponding to said ion beam absorber pattern, and forming a desired ion beam absorber pattern by developing said FIB-exposed FIB sensitive resist.

Claim 19

A method of implanting impurity ions to form an impurity profile having varied depths in a wafer having a major surface, comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern from a single-layer material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, the absorbency of ions by said single-layer material depending upon said varying thickness, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer to form source/drain regions, removing said ion beam absorber pattern, and after the step of removing, forming a gate electrode between said source/drain regions on said major surface with a gate insulation film therebetween, wherein said step of forming said ion beam absorber pattern comprises the steps of: forming an ion beam absorber on the whole major surface of said wafer, and FIB-etching said ion beam absorber so as to allow said ion beam absorber pattern to have a varying thickness corresponding to said ion beam absorber pattern.

Claim 20

A method of implanting impurity ions to form an impurity profile having varied depths in a wafer having a major surface, comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern from a single-layer material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, the absorbency of ions by said single-layer material depending upon said varying thickness, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer to form source/drain regions, removing said ion beam absorber pattern, and after the step of removing, forming a gate electrode between said source/drain regions on said major surface with a gate insulation film therebetween, wherein said step of forming said ion beam absorber pattern comprises the steps of: forming an ion beam absorber on the whole major surface of said wafer, and FIB-etching said ion beam absorber so as to allow said ion beam absorber pattern to have a varying thickness corresponding to said ion beam absorber pattern.

Claim 23

A method of implanting impurity ions to form an impurity profile having varied depths in a wafer having a major surface, comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern from a single-layer material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, the absorbency of ions by said single-layer material depending upon said varying thickness, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer to form source/drain regions, removing said ion beam absorber pattern, and after the step of removing, forming a gate electrode between said source/drain regions on said major surface with a gate insulation film therebetween, wherein said step of forming said ion beam absorber pattern comprises the steps of: forming a layer having a varying thickness corresponding to said ion beam absorber pattern on the whole major surface of said wafer, and lithographing the layer to be said ion beam absorber pattern by employing an X-ray or focused ion beam, and said step of forming the layer to be said ion beam absorber pattern and said step of lithography are repeated.

Claim 24

A method of implanting impurity ions to form an impurity profile having varied depths in a wafer having a major surface, comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern from a single-layer material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, the absorbency of ions by said single-layer material depending upon said varying thickness, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer to form source/drain regions, removing said ion beam absorber pattern, and after the step of removing, forming a gate electrode between said source/drain regions on said major surface with a gate insulation film therebetween, wherein said step of forming said ion beam absorber pattern comprises the steps of: forming a layer having a varying thickness corresponding to said ion beam absorber pattern on the whole major surface of said wafer, and lithographing the layer to be said ion beam absorber pattern by employing an X-ray or focused ion beam, and said step of forming the layer to be said ion beam absorber pattern and said step of lithography are repeated.

Claim 25

A method of implanting impurity ions in a major surface of a wafer to form an impurity profile varying in concentration and depth of impurity ions implanted along a length of the wafer, said impurity profile having at least three separate concentrations and depths of impurity ions obtained by a single ion implantation, concentration and depth being ≧0, said method comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern having a least a single layer of material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer, the absorbency of ions by said ion beam absorber pattern depending upon the varying thickness, and removing said ion beam absorber pattern at least in a region having a thickness greater than zero and in which ions have been implanted, wherein said ion beam absorber pattern has at least three separate thicknesses, each corresponding to a respective concentration and depth of impurity ions of the impurity profile and said step of forming said ion beam absorber pattern comprises the steps of: forming an X-ray sensitive resist to be said ion beam absorber pattern on the whole major surface of said wafer, X-ray exposing said X-ray sensitive resist by employing an X-ray exposure pattern mask relative to the shape of said ion beam absorber pattern by developing said X-ray exposed X-ray sensitive resist.

Claim 26

A method of implanting impurity ions in a major surface of a wafer to form an impurity profile varying in concentration and depth of impurity ions implanted along a length of the wafer, said impurity profile having at least three separate concentrations and depths of impurity ions obtained by a single ion implantation, concentration and depth being ≧0, said method comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern having a least a single layer of material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer, the absorbency of ions by said ion beam absorber pattern depending upon the varying thickness, and removing said ion beam absorber pattern at least in a region having a thickness greater than zero and in which ions have been implanted, wherein said ion beam absorber pattern has at least three separate thicknesses, each corresponding to a respective concentration and depth of impurity ions of the impurity profile and said step of forming said ion beam absorber pattern comprises the steps of: forming an X-ray sensitive resist to be said ion beam absorber pattern on the whole major surface of said wafer, X-ray exposing said X-ray sensitive resist by employing an X-ray exposure pattern mask relative to the shape of said ion beam absorber pattern by developing said X-ray exposed X-ray sensitive resist.

Claim 27

A method of implanting impurity ions in a major surface of a wafer to form an impurity profile varying in concentration and depth of impurity ions implanted along a length of the wafer, said impurity profile having at least three separate concentrations and depths of impurity ions obtained by a single ion implantation, concentration and depth being ≧0, said method comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern having a least a single layer of material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer, the absorbency of ions by said ion beam absorber pattern depending upon the varying thickness, and removing said ion beam absorber pattern at least in a region having a thickness greater than zero and in which ions have been implanted, wherein said ion beam absorber pattern has at least three separate thicknesses, each corresponding to a respective concentration and depth of impurity ions of the impurity profile, and said step of forming said ion beam absorber pattern comprises the steps of: forming an FIB sensitive resist on the whole major surface of said wafer, FIB-exposing said FIB sensitive resist so as to allow said FIB sensitive resist to have a varying thickness corresponding to said ion beam absorber pattern, and forming a desired ion beam absorber pattern by developing said FIB-exposed FIB sensitive resist.

Claim 28

A method of implanting impurity ions in a major surface of a wafer to form an impurity profile varying in concentration and depth of impurity ions implanted along a length of the wafer, said impurity profile having at least three separate concentrations and depths of impurity ions obtained by a single ion implantation, concentration and depth being ≧0, said method comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern having a least a single layer of material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer, the absorbency of ions by said ion beam absorber pattern depending upon the varying thickness, and removing said ion beam absorber pattern at least in a region having a thickness greater than zero and in which ions have been implanted, wherein said ion beam absorber pattern has at least three separate thicknesses, each corresponding to a respective concentration and depth of impurity ions of the impurity profile, and said step of forming said ion beam absorber pattern comprises the steps of: forming an FIB sensitive resist on the whole major surface of said wafer, FIB-exposing said FIB sensitive resist so as to allow said FIB sensitive resist to have a varying thickness corresponding to said ion beam absorber pattern, and forming a desired ion beam absorber pattern by developing said FIB-exposed FIB sensitive resist.

Claim 29

A method of implanting impurity ions in a major surface of a wafer to form an impurity profile varying in concentration and depth of impurity ions implanted along a length of the wafer, said impurity profile having at least three separate concentrations and depths of impurity ions obtained by a single ion implantation, concentration and depth being ≧0, said method comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern having a least a single layer of material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer, the absorbency of ions by said ion beam absorber pattern depending upon the varying thickness, and removing said ion beam absorber pattern at least in a region having a thickness greater than zero and in which ions have been implanted, wherein said ion beam absorber pattern has at least three or continuous separate thicknesses, each corresponding to a respective concentration and depth of impurity ions of the impurity profile, and said step of forming said ion beam absorber pattern comprises the steps of: forming an ion beam absorber on the whole major surface of said wafer, and FIB-etching said ion beam absorber so as to allow said ion beam absorber pattern to have a varying thickness corresponding to said ion beam absorber pattern.

Claim 30

A method of implanting impurity ions in a major surface of a wafer to form an impurity profile varying in concentration and depth of impurity ions implanted along a length of the wafer, said impurity profile having at least three separate concentrations and depths of impurity ions obtained by a single ion implantation, concentration and depth being ≧0, said method comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern having a least a single layer of material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer, the absorbency of ions by said ion beam absorber pattern depending upon the varying thickness, and removing said ion beam absorber pattern at least in a region having a thickness greater than zero and in which ions have been implanted, wherein said ion beam absorber pattern has at least three or continuous separate thicknesses, each corresponding to a respective concentration and depth of impurity ions of the impurity profile, and said step of forming said ion beam absorber pattern comprises the steps of: forming an ion beam absorber on the whole major surface of said wafer, and FIB-etching said ion beam absorber so as to allow said ion beam absorber pattern to have a varying thickness corresponding to said ion beam absorber pattern.

Claim 31

A method of implanting impurity ions in a major surface of a wafer to form an impurity profile varying in concentration and depth of impurity ions implanted along a length of the wafer, said impurity profile having at least three separate concentrations and depths of impurity ions obtained by a single ion implantation, concentration and depth being ≧0, said method comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern having at least a single layer of material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer, the absorbency of ions by said ion beam absorber pattern depending upon the varying thickness, and removing said ion beam absorber pattern at least in a region having a thickness greater than zero and in which ions have been implanted, wherein said ion beam absorber pattern has at least three separate thicknesses, each corresponding to a respective concentration and depth of impurity ions of the impurity profile, and said step of forming said ion beam absorber pattern comprises the steps of: forming a layer having a varying thickness corresponding to said ion beam absorber pattern on the whole major surface of said wafer, lithographing the layer to be said ion beam absorber pattern by employing an X-ray or focused ion beam, and repeating said step of forming a layer and said step of lithographing are repeated.

Claim 32

A method of implanting impurity ions in a major surface of a wafer to form an impurity profile varying in concentration and depth of impurity ions implanted along a length of the wafer, said impurity profile having at least three separate concentrations and depths of impurity ions obtained by a single ion implantation, concentration and depth being ≧0, said method comprising the steps of: forming on the major surface of said wafer an ion beam absorber pattern having at least a single layer of material, said ion beam absorber pattern varying in thicknesses along its length depending upon said impurity profile, directing said ion beam through said ion beam absorber pattern onto the major surface of said wafer, the absorbency of ions by said ion beam absorber pattern depending upon the varying thickness, and removing said ion beam absorber pattern at least in a region having a thickness greater than zero and in which ions have been implanted, wherein said ion beam absorber pattern has at least three separate thicknesses, each corresponding to a respective concentration and depth of impurity ions of the impurity profile, and said step of forming said ion beam absorber pattern comprises the steps of: forming a layer having a varying thickness corresponding to said ion beam absorber pattern on the whole major surface of said wafer, lithographing the layer to be said ion beam absorber pattern by employing an X-ray or focused ion beam, and repeating said step of forming a layer and said step of lithographing are repeated.