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Single Scan Mask Deposition Alignment Site

IP.com Disclosure Number: IPCOM000089592D
Original Publication Date: 1977-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Jones, RE: AUTHOR [+2]

Abstract

A scan site, as shown in the figure, obtains both X and Y direction alignment measurements. Each mask deposition layer is represented by two 45 Degrees triangles. The dimensions W and S are the same for each layer, from layer 1 to layer n for n number of deposition layers required to complete the device being constructed. It can be shown that, by making 0 equal to 45 Degrees, the error introduced by a skewed scan is minimized.

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Single Scan Mask Deposition Alignment Site

A scan site, as shown in the figure, obtains both X and Y direction alignment measurements. Each mask deposition layer is represented by two 45 Degrees triangles. The dimensions W and S are the same for each layer, from layer 1 to layer n for n number of deposition layers required to complete the device being constructed. It can be shown that, by making 0 equal to 45 Degrees, the error introduced by a skewed scan is minimized.

For each layer, three scan readings are taken: A(n), B(n) and C(n) for the nth layer, for instance. These readings are the X coordinates of the points at which the measuring means, such as a stylus, steps up or down as it crosses certain edges along the scan line.

The windage of the nth layer is then determined by: Z(n) = C(n) - A(n) - W - e where e is a correction for the stylus geometry.

The X and Y components of the mask misalignment between any two layers m and n are given by: (Delta X)(m,n) = 1/2 (A(n) - A(m) + C(n) - C(m)) - (n - m) (W + S) (Delta Y)(m,n) = B(m) - B(m) + 1.207(C(n) - C(m)) - 0.207 (A(n) - A(m).

The expressions for the X and Y misalignment are independent of stylus geometry. A single scan provides X and Y alignment information for each deposition layer by the use of individual sites containing two 45 Degrees triangles aligned in the X direction with facing hypotenuse.

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