Patent Number: 
Section: claims

1. A partial implantation method to implant dopant ions at different densities into a plurality of regions, including first and second regions, defined in a wafer by means of a boundary line, the method comprising:defining a first implantation zone as a remaining part of the first region excluding a specific part of the first region close to the boundary line, a second implantation zone as a remaining part of the second region except for a specific part of the second region close to the boundary line, and a third implantation zone as a remaining part of the wafer including the boundary line, excluding the first and second implantation zones; andimplanting dopant ions at a first density into the first implantation zone, at a second density different from the first density into the second implantation zone, and at a third density between the first and second densities into the third implantation zone,wherein a slope of the density of dopants in the third implantation zone can be adjusted by varying the area of at least one of the first and second implantation zones. 2. The method as set forth in claim 1, wherein the first implantation zone has an area corresponding to about 98% of the area of the first region. 3. The method as set forth in claim 1, wherein the second implantation zone has an area corresponding to about 98% of the area of the second region. 4. The method as set forth in claim 1, wherein:the first density of the dopant ions implanted in the first implantation zone is lower than the third density of the dopant ions implanted in the third implantation zone; andthe second density of the dopant ions implanted in the second implantation zone is higher than the third density of the dopant ions implanted in the third implantation zone. 5. The method as set forth in claim 4, wherein:the first density is lower than the third density by about 5%; andthe second density is higher than the third density by about 5%. 6. The method as set forth in claim 1, wherein the boundary line between the first and second regions is formed to vertically or horizontally bisect the wafer. 7. The method as set forth in claim 1, wherein the boundary line between the first and second regions is formed to divide the wafer into a center region and a peripheral region. 8. A partial implantation method to implant dopant ions at different densities into a plurality of regions, the method comprising:defining a boundary line in a wafer, wherein the boundary line divides the wafer into first and second regions;defining a first implantation zone as a first portion of the first region, excluding a second portion of the first region close to the boundary line;defining a second implantation zone as a first portion of the second region, excluding a second portion of the second region close to the boundary line;defining a third implantation zone as the second portions of the first and second regions, including the boundary line; andimplanting dopant ions at a first density into the first implantation zone, at a second density different from the first density into the second implantation zone, and at a third density between the first and second densities into the third implantation zone,wherein a slope of the density of dopants in the third implantation zone can be adjusted by varying the area of at least one of the first and second implantation zones. 9. The method of claim 1, wherein the slope of the density of dopants in the third implantation zone can be increased by increasing the area of at least one of the first and second implantation zones. 10. The method of claim 1, wherein the slope of the density of dopants in the third implantation zone can be decreased by decreasing the area of at least one of the first and second implantations zones.