System for precise position registration
An apparatus for enabling accurate retaining of a precise position, such as for reacquisition of a microscopic spot or feature having a size of 0.1 mm or less, on broad-area surfaces after non-in situ processing. The apparatus includes a sample and sample holder. The sample holder includes a base and three support posts. Two of the support posts interact with a cylindrical hole and a U-groove in the sample to establish location of one point on the sample and a line through the sample. Simultaneous contact of the third support post with the surface of the sample defines a plane through the sample. All points of the sample are therefore uniquely defined by the sample and sample holder. The position registration system of the current invention provides accuracy, as measured in x, y repeatability, of at least 140 μm.
1. A system for precise position registration comprising:
a. a sample holder including
i. a base; and
ii. three support posts;
b. a sample including:
i. a body having a top and a bottom side;
ii. a cylindrical depression in said bottom side of said body; and
iii. a U-groove depression in said bottom side of said body.
2. The position registration system of claim 1 wherein said support posts include:
a. a first support post having a first conical tip;
b. a second support post having a second conical tip; and
c. a third support post having a hemispherical tip.
3. The position registration system of claim 2 wherein
a. said cylindrical depression includes a side wall and an inner surface within said body; and
b. said U-groove depression includes short and long side walls and an inner surface.
4. The position registration system of claim 3 wherein
a. said first conical tip of said first support post includes an outer surface; and
b. said second conical tip of said second support post includes an outer surface.
5. The position registration system of claim 4 wherein said sample holder is located under said sample and:
a. said first conical tip of said first support post engages said side wall of said cylindrical depression in such a manner that said first conical tip is offset from said inner surface of said cylindrical depression;
b. said second conical tip of said second support post engages said short side walls of said U-groove depression in such a manner that said second conical tip is offset from said inner surface of said U-groove depression; and
c. said hemispherical tip of said third support post engages said bottom side of said body.
6. The position registration system of claim 5 wherein said support posts are cylindrical in shape.
7. The position registration system of claim 3 wherein said outer surfaces of said first and second conical tips, said side wall of said cylindrical depression, and said short side walls of said U-groove depression have smooth walls.
8. The position registration system of claim 1 which includes an accuracy, as measured in x, y repeatability, of at least 140 μm.