Ushio Denki Kabushiki Kaisha

Ushio Denki

Shinetsu Miura

Yoshiki Mimura

Shinji Suzuki

Tetsuji Arai

Takeshi Minobe

Nobutaka Kajiura

Kazumoto Tochihara

A device for exposure of the peripheral area of a wafer with a small shape and at low costs in which, using a device for stepped exposure of the peripheral area of a wafer, the peripheral area of a wafer can be exposed in a ring shape. A wafer to which resist has been applied is placed on a rotary support and rotated once. The seated state of the wafer and a singular orienting shape such as an Ori-Fla or the like are determined. Based on this information, the wafer is positioned in a given position. Then, the rotary support is moved by means of an X-Y support and exposure is performed. If the coordinates of the center of rotation (X.THETA., Y.THETA.) are taken accurately a ring shape is approached in practice (if, for example, .THETA.=0.1.degree. and for a polygon with 3600 corners a circle is approached), there is no problem. Two exposure devices are not necessary, specifically one device for stepped exposure of the peripheral area of a wafer and one device for ring-shaped exposure of the peripheral area. The peripheral area of the wafer can be exposed both in a step-shape and also ring-shape with a single device. Therefore the area occupied by the device can be reduced, as can equipment costs. In the case of stepped exposure of one part of the peripheral area of the wafer and ring-shaped exposure of the other part thereof, the wafer need not be transported. Furthermore, the peripheral edge of the wafer need be determined only once. Therefore throughput can be increased. Using a device for stepped exposure of the peripheral area of the wafer, the peripheral area of the wafer can be exposed in a ring shape without using a memory with a high capacity. The peripheral area of the wafer can be exposed in a ring shape without bringing the wafer center and the center of the rotary support into agreement with one another. Therefore a centering device is unnecessary. The centering process is eliminated. Thus both the device and actuation can be simplified.

Device for exposing the peripheral area of a wafer

To increase operating efficiency and prevent operating errors, such as adjustment errors and the like, by automatic computation of the distance between the workpiece alignment marks, according to the invention, workpiece alignment marks located at two locations on a workpiece are subjected to image recording by alignment units, their positions are stored as first positions, then by rotation of the workpiece by a preset very small angle, the workpiece alignment marks located at two locations on the workpiece are determined again, and their positions are stored as second positions. Based on the data of the first and second positions, the distance between the workpiece alignment marks is determined. Then, based on the distance data, the angular offset of the workpiece is determined. After correction of this angular offset, the mask and/or the workpiece is/are moved such that the images of the mask alignment marks and the workpiece alignment marks come to rest on top of one another.

Process for positioning a mask relative to a workpiece

To effect exposure of the peripheral area of a wafer to remove an unnecessary resist with a step shape in a development process with high precision and ease, even if the position has errors, in which a circuit pattern is formed on a semiconductor wafer in a preceding process, according to the invention, before exposing the unnecessary resist on a wafer outside of the area on which a pattern is formed, the position of a singular shaped area, such as an 'orientation flat' or the like is determined by a unit for determining the peripheral edge area of the wafer, and the rotating carrier is driven and the wafer is rotated until the singular shaped area is positioned in a predetermined position. Furthermore, according to the invention, a unit for determining the alignment marks computes and stores the positions of predetermined alignment marks, by which positional errors in the location in which the circuit pattern is formed are corrected. Then, the rotating carrier is driven again, and fine adjustment of the position of the exposure area on the wafer is performed.

Process for exposing the peripheral area of a semiconductor wafer for

A method for exposing a peripheral part of a wafer according to the present invention is to expose the peripheral part, taking account of a correcting angle determined by calculating the amount of misalignment between a center of a wafer and a rotational center for the wafer from the amount of displacement of a sensor for detecting a peripheral edge. Therefore, any wafer-centering motion and mechanism are not required, and this method is higher in precision of exposing position.

Growing community of inventors

Kawasaki, Japan

Shinetsu Miura