Patent Application
20060119367
This application claims priority to German patent application number DE 10 2004 058 126.6, filed Dec. 2, 2004, which is incorporated herein by reference in its entirety.
The invention relates to an apparatus for inspecting the front side and back side of a semiconductor substrate.
In semiconductor manufacture, wafers are processed sequentially in a multiplicity of processing steps during the production process. The quality requirements for structures applied to the wafers increase with increasing integration density. As a result, the need to test for defects, not only on the front side of the wafer, but to find defects on the back side of the wafer as well, increases. The front side of the wafer is the side to which the various structures are applied.
U.S. Pat. No. 6,559,938 B1 discloses a device for simultaneously inspecting for defects on the front side and the back side of a wafer. The wafer lies on a table that exhibits an open channel that in its length corresponds to the diameter of the wafer. A detector moves in the channel and therefore takes an image of a part of the wafer. In order to image the entire surface of the wafer, the wafer can be rotated on the table. The friction between the table and the wafer is minimized by corresponding air bearings. Simultaneous imaging or inspection of the entire surface of the front side and the back side of the wafer is not possible with this apparatus.
U.S. Pat. No. 6,747,464 B1 discloses a wafer holder with which the back side of the wafer can be observed and measurements can be taken on the front side of the wafer. The wafer holder may be used in machines for automatically inspecting a wafer. The wafer holder is implemented such that the front side and the back side of the wafer are almost completely accessible from both sides. Simultaneous imaging of the front side and the back side of the wafer is not possible with the wafer holder.
US patent application 2004/0087146 discloses a ring-shaped wafer holder. The wafer holder possesses a bracket for the wafer and is open at the top so that the wafer can be completely inspected from one side. The wafer rests with its other side on a crib that is implemented with an inspection window through which a fraction of the side of the wafer that lies on the crib can be inspected. Simultaneous and complete inspection of the front side and the back side of the wafer is not possible with this wafer holder.
German published application DE 101 21 115 A1 discloses a holding apparatus for a wafer. The holding apparatus possesses two grippers that in their closed state surround the edge of the wafer. The front side and back side of the wafer are therefore not covered. The holding apparatus can be swiveled, which enables visual inspection of the back side of the wafer.
German published application DE 103 07 373 A1 discloses a method and an apparatus for inspecting semiconductor wafers, taking die-saw designs into consideration. An image of the entire wafer can be constructed from a multiplicity of individual images. In the process, the size of the image field of the camera is selected such that the current die/saw design is taken into account.
The object underlying the invention is to create an apparatus with which it is possible to inspect or image both the front side and the back side of a disc-shaped object simultaneously.
This object is solved by an apparatus for inspecting the front side and the back side of a disc-shaped object, which exhibits a detection unit with a first detector element facing the front side and a second detector element facing the back side of the disc-shaped object, and in which a means is provided for generating a relative movement between the detection unit and the disc-shaped object so that an image is made of the front side and the back side of the disc-shaped object.
It is particularly advantageous that the apparatus for inspecting the front side and back side of a disc-shaped object comprise a detection unit. The detection unit has a first detector element facing the front side of the disc-shaped object and a second detector element facing the back side of the disc-shaped object. A means is provided for generating a relative movement between the detection unit and the disc-shaped object so that an image is made of the front side and the back side of the disc-shaped object.
The disc-shaped object may be a wafer on a semiconductor substrate, or on a glass substrate, or a mask for lithography, or a flat-panel display.
An edge grip system is provided that fixes the disc-shaped object in place. The first and the second detector element is a linear detector with integrated optic and an integrated light.
The means for generating a relative movement between the detection unit and the disc-shaped object is a movement device, whereby the first and a second detector element are attached to the movement device, which moves the first and the second detector element along the top and bottom of the disc-shaped object when the disc-shaped object is fixed in place.
The first and the second detector element is a linear detector with an integrated optic, whereby an external light is provided for the two-dimensional object. The light is fixed in place and glances across the wafer.
The first and the second detector element have at least the same width as the two-dimensional object.
The above and other features of the invention including various novel details of construction and combinations of parts, and other advantages, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular method and device embodying the invention are shown by way of illustration and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.
In the accompanying drawings, reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale; emphasis has instead been placed upon illustrating the principles of the invention.
In the diagram, the subject of the invention is schematically represented and described below based on the figures. They show:
While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| DE 102004058126.6 | Dec 2004 | DE | national |
