Method and apparatus for examining semiconductor wafers in a context of die/SAW design
AssigneeLeica Microsystems Semiconductor GmbH
InventorDetlef Michelsson
Life of this patent
Estimating the term…
Abstract
The invention takes into account the fact that the size of the SAWs varies greatly depending on the stepper and the die size (design). In general, it cannot be assumed that one SAW can be imaged with one camera image. A SAW is preferably broken down into regular logical parts (segments) of identical size. A SAW index is allocated to each logical SAW segment. One image field of the camera can image only a certain number of these SAW segments. An index, hereinafter called an image field segment index, is allocated to each segment of an image field, hereinafter called an image field segment.
Claims26
A method for analyzing at least one wafer which has a plurality features that were generated with a SAW, comprising the steps of:
- moving a camera, having an image flied, over a wafer and thereby acquiring with its image field a plurality of images;
- initializing in a learning phase the image field of the camera, wherein the image field of the camera is divided into SAW-segment-imaging image field segments in such a way that after a definable interval of acquired images, a repetition of an identical allocation of imaged SAW segments in image field segments occurs;
- and
- carrying out comparison operations in run phases, in which the image field segments of images that have an identical allocation of image field segments to imaged SAW segments are compared with one another and/or with a specific master.
An apparatus for the analysis of surface images of at lest one wafer, wherein the at least one wafer has features that are generated using a SAW, the apparatus comprising:
- a camera to acquire a plurality of images of the at least one wafer, wherein the camera defines an image field;
- a memory region in which the plurality of images of the wafer, acquired with the camera, are storable;
- means for initializing in a learning phase in which the image field of the camera is divided into SAW-segment-imaging image field segments in such a way that after a definable interval of acquired images, a repetition of an identical allocation of imaged SAW segments in image field segments occurs;
- and
- a processing unit for carrying out comparison operations in such a way that in, the image field segments of images that have an identical allocation of image field segments to imaged SAW segments are compared with one another and/or with a specific model.
A software program for a computer, wherein the software program makes the computer to operate according to a method for analyzing at least one wafer which has a plurality features that were generated with a SAW, comprising the steps of:
- moving a camera, having an image flied, over a wafer and thereby acquiring with its image field a plurality of images;
- initializing in a learning phase the image field of the camera, wherein the image field of the camera is divided into SAW-segment-imaging image field segments in such a way that after a definable interval of acquired images, a repetition of an identical allocation of imaged SAW segments in image field segments occurs;
- and
- carrying out comparison operations in run phases, in which the image field segments of images that have an identical allocation of image field segments to imaged SAW segments are compared with one another and/or with a specific master.
A data medium for a computer stores of a software program wherein the software program makes the computer to operate according to a method for analyzing at least one wafer which has a plurality features that were generated with a SAW, comprising the steps of:
- moving a camera, having an image flied, over a wafer and thereby acquiring with its image field a plurality of images;
- initializing in a learning phase the image field of the camera, wherein the image field of the camera is divided into SAW-segment-imaging image field segments in such a way that after a definable interval of acquired images, a repetition of an identical allocation of imaged SAW segments in image field segments occurs;
- and
- carrying out comparison operations in run phases, in which the image field segments of images that have an identical allocation of image field segments to imaged SAW segments are compared with one another and/or with a specific master.
Dependencies are inferred from the claim text.