Geometrical instruments – Miscellaneous – Light direction
Reexamination Certificate
1999-07-02
2001-12-25
Gutierrez, Diego (Department: 2859)
Geometrical instruments
Miscellaneous
Light direction
C033S041400, C033S501050, C033S547000, C033S549000, C033S555100
Reexamination Certificate
active
06332275
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The invention relates to a margin inspector for IC wafers, and more particularly to an inspecting apparatus helpfull to visibly examine the washout margin of an IC wafer after a coating process.
(2) Description of the Prior Art
Conventionally, in the process of coating a PR layer or the like membrane onto a wafer, the manufacturing device usually washes out a periphery ring of PR or the like material by a substantial width along the circular edge of the wafer for forming a concise available area thereinside on the wafer. Generally, the allowable width of such periphery ring is ranged between 1.0 mm and 2.0 mm. As long as the width of the periphery ring falls into the allowable range, the wafer is deemed as qualified to proceed the next manufacturing process. Yet, once the width of the periphery ring on a wafer falls beyond the allowable range, the wafer is deemed as an ill-conditional one and needs further amendment.
One of the tools in the art to examine the specifications of the washout periphery ring on a wafer is the microscope. However, the investigation on the periphery ring by a microscope usually implies time-consuming work. To save time and labor in examining the ring, survey by eyesight is usually applied in the field. Yet, one of the disadvantages in eyesight survey is the problem in accurately locating an ill-conditional wafer. Disputation on the qualification usually arises while a wafer is on the verge of allowance; i.e. the width of the periphery ring is around 2.0 mm or 1.0 mm. In the case that a qualified wafer is accidentally determined to be ill-conditional, additional cost and labor on unnecessary wafer amendment can be inevitable. In the case that an unqualified wafer passes the examination, further loss in the sequent manufacturing processes can be foreseen. Obviously, in examining the periphery ring of the wafer after a coating process, neither above case is welcome.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a margin inspector for IC wafers, which applies several inspecting lines to correctly locate by eyesight a wafer having a qualified washout periphery ring, for facilitating the wafer qualification control after a coating process.
According to one embodiment of the present invention, a margin inspector for IC wafers comprises an upper plate and a supporting portion.
The upper plate, which is formed as a transparent plate, has a plurality of concentric circular segments thereon for establishing a set of reference lines to examine the periphery ring of the wafer located under the upper plate while in examining operation.
The supporting portion, which is connected with the upper plate for supporting purpose, is used to form a working space between the supporting portion and the upper plate, for accommodating the wafer to be examined.
In one embodiment of the present invention, the set of reference lines includes an upper bound line and a lower bound line, for indicating an upper bound and a lower bound on an inner diameter of the periphery ring, respectively. Preferably, the set of reference lines further includes a median line for locating a standard value on the inner diameter of the periphery ring.
Preferably, the set of reference lines is formed as a set of concentric circles.
In one embodiment of the present invention, the margin inspector for IC wafers includes at least 3 spacers, which are extruding from a bottom face of the upper plate. While the wafer in examining operation, the spacers contact substantially at edge of the wafer thereunder for avoiding direct contact of the upper plate and the wafer. Preferably, among the spacers, there exist at least three spacers capable of forming an acute triangle.
In one embodiment of the present invention, the supporting portion comprises a supporting frame and a base. The aforesaid working space is provided between the base and the upper plate, and the supporting frame is used to fix the base to the upper plate.
In one embodiment of the supporting frame, the supporting frame is connected perpendicular to the upper plate; such that, while in examining operation, the wafer in the working space can be convenient at a position having the wafer's edge contacting with an inner surface of the supporting frame. Preferably, the inner surface of the supporting frame is shaped to have a curvature that is the same as a curvature of the edge of the wafer.
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Tsai Wen-Wang
Wu Chun-Yan
Bacon & Thomas
Gonzalez Madeline
Gutierrez Diego
Mosel Vitelic Inc.
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