Optimetrix Corporation

Hidden Valley Associates, Inc.

Compact Spindle Bearing Corporation

Other

Eaton Corporation

Eaton-optimetrix Inc.

American Fitness, Inc.

Amfit, Inc.

Micro-stage, Inc.

Edward H Phillips

Karl-Heinz Johannsmeier

Lawrence A Wise

In an X-Y addressable workpiece positioner the workpiece to be positioned, such as a semiconductive wafer to be aligned with a mask image, is coupled to move with a work stage moveable in X and Y direction and having a two-dimensional array of positioning indicia affixed thereto for movement therewith. An enlarged image of a portion of the positioning array is projected onto a relatively stationary sensor stage to derive an output determinative of the X and Y coordinates of the positioning array relative to the position of the sensor. The sensed X and Y coordinates of the positioning array are compared with the X and Y coordinates of a reference positioning address to derive an error output. The work stage is moved in response to the error output for causing the workpiece to be positioned to the reference address. In a preferred embodiment of a mask aligner, the approximately stationary sensing stage is moved relative to the enlarged image of the positioning array for interpolating the X and Y coordinates of the sensed address. A viewing system is arranged for permitting the operator to superimpose the image of a pattern on the reference addressed position of the semiconductive wafer with a mask image. The sensing stage is moved by the operator to obtain precise registration of the images, thereby zeroing the reference position address to the interpolated value. The machine then sequentially steps the interpolated (zeroed) reference position address by predetermined increments, related to the size mask pattern to be projected onto the wafer, to cause the wafer to be sequentially exposed to the mask pattern in different regions thereof.

X-Y addressable workpiece positioner and mask aligner using same

An improved solid state commutated linear motor with an ironless multiphase armature is disclosed which has a magnetic field array having periodic alternating polarity, an ironless multiphase armature, and a solid state commutating system for driving a moving element and positioning it with respect to a reference element. In one embodiment, the magnetic field array is elongated and fixedly located with respect to the reference element, and the ironless multiphase armature is fixedly located with respect to the moving element. In a second embodiment, the ironless multiphase armature is elongated and fixedly located with respect to the reference element, and the magnetic field array is fixedly located with respect to the moving element. The magnetic field array is generated by an array of spaced alternate north and south poled magnets having an inter-pole distance L. The ironless multiphase armature is comprised of coils having a center-line span equal to the inter-pole distance L, wherein the coils are interleaved and staggered to form the various phases. Solid state switches are used to commutate the phases by first faulting a phase as it approaches a space between magnetic poles and then reversing the connections of that phase as it leaves the space between the magnetic poles.

Solid state commutated linear motor with an ironless multiphase armature

An improved gas bearing X-Y-.theta. stage assembly is disclosed which has a base, a stage element with three retroreflectors fixedly mounted thereto, and a control system for controlling the movement of the stage element. The control system is made up of three interferometer measuring systems for measuring parameters associated with changes in position of the three retroreflectors as the stage element moves. Also, the control system includes a transport system for moving the three interferometers to maintain optical coupling between the interferometers and retroreflectors. In addition, the control system includes control circuitry for causing the stage element to move to a preselected X-Y-.theta. position in response to signals from the interferometer measuring systems. In one embodiment, a first interferometer of a first one of the three interferometer measuring systems is moved linearly by the transport system on a gas bearing slide in a direction parallel to the Y-axis of the system, while second and third interferometers of the other two interferometer measuring systems are moved together on a second gas bearing slide parallel to the X-axis of the system.

Gas bearing X-Y-.theta. stage assembly

An improved step and repeat alignment and exposure system for printing an image of a recticle onto a semiconductive wafer. A unit magnification catadioptric lens projects the recticle image onto the semiconductive wafer, and includes prisms to separate the image plane of the lens from the object plane. The semiconductive wafer is supported on stage means, which stage means provide motion in the X,Y directrions. Viewing port means supplement the unit magnification catadioptric lens to provide a direct view of a portion of the semiconductive wafer which portion has been illuminated by the projected recticle image. A beam splitter is formed on a face of one of the prisms of the unit magnification catadioptric lens and is supplemented by an additional prism which provides optical path compatibility. A novel microscope structure is employed with large aperture focusing lenses to permit the infinity corrected objectives to translate about the field of view of the viewing port means without the requirement that any utilization device also translate in unison. Means are also provided for calibrating the position of the stage with respect to the recticle. Included are stage reference means which image a stage reference mark into the image plane of the unit magnification catadioptric lens when said stage reference means are illuminated by the projected recticle image. Means are provided for determining offset values between the projected recticle image and the stage reference mark and for utilizing said offsets in controlling the position of the stage. Further, means are provided for focusing and leveling the surface of the semiconductive wafer, wherein said means maintain, in a servo-controlled manner, said surface in a known position with respect to the stage. A six-degree of freedom support system is controlled by said focusing and leveling means to provide vertical position, pitch and roll movement of the semiconductive wafer.

Step-and-repeat alignment and exposure system

Statically pressurized gas bearings employ improved bearing pockets, each including one or more slots arranged in a double cross, star or other configuration, and supplemental gas exhaust slots, as well as stepped annular land flow restrictors, to optimize bearing stability and operational bandwidth.

Gas bearing

A dark field alignment system is provided wherein a bifurcated light source, including a secondary channel having spot sources of light located in a plane conjugate to the object plane of a reduction lens and directed through a peripheral ring of a plane conjugate to the apertgure plane of the reduction lens, illuminates the object plane of the reduction lens. Reflected and defracted light from an alignment mark of a semiconductive wafer in the image plane of the reduction lens is captured by a mirror located near the aperture plane of the reduction lens. This light is refocused to another plane conjugate to the object plane of the reduction lens and imaged onto detector arrays to provide alignment information. Also provided is an alignment mark system wherein the relative positions of alignment windows in an array of alignment windows, and alignment patterns in a corresponding array of alignment patterns are selected such that an image of an edge of each reticle alignment window illuminates a first edge of a counterpart alignment mark without illuminating any other edges of the alignment marks when the marks and windows are properly aligned.

Dark field alignment and alignment mark systems

An improved multi-axis gas bearing stage assembly is disclosed which has a base, an intermediate stage element, a stage, and a control system for controlling the movement of the intermediate stage element and the stage. The control system includes first and second Y-axes positioning sub-systems for differentially positioning first and second ends of the intermediate stage element along first and second Y-axes of motion, with respect to the base, and an X.sub.i -axis positioning sub-system for positioning the stage along an X.sub.i -axis of motion, with respect to the intermediate stage element. In one embodiment, the positioning sub-systems comprise motor-encoder driven leadscrews. In a second embodiment, the positioning sub-systems comprise linear motors, measuring scales, and read heads. In a third embodiment, the positioning sub-systems comprise linear motors and interferometer measuring systems. A method of achieving orthogonality between the Y- and X.sub.i -axes that features an orthogonality alignment standard is disclosed. In a another embodiment, the differential positioning capability of the first and second Y-axes is utilized for positioning the intermediate stage element along a .theta.-axis about a Z-direction orthogonal to both the Y- and X-axes, and a method of rotationally aligning a semiconductive wafer is disclosed. In other embodiments, two methods of kinematically positioning the improved multi-axis stage assembly within a utilization apparatus are disclosed. In another embodiment, three retroreflectors of an interferometer measuring system are mounted directly on a wafer chuck, located on the stage, and a transport system moves three interferometers rotationally, to maintain optical coupling between the interferometers and the retroreflectors. In still another embodiment, five retroreflectors are mounted directly on the wafer chuck and a five axis interferometer measuring system is utilized to eliminate all Abbe offset measurement errors in the position of a semiconductive wafer, placed upon the wafer chuck, along the X, Y, and .theta.-axes of motion.

Multi-axis gas bearing stage assembly

An improved step and repeat alignment and exposure system for printing an image of a reticle onto a semiconductive wafer. A projection lens, such as a unit magnification catadioptric lens, projects the reticle image onto the semiconductive wafer. Novel viewing port means provide a direct view of a portion of the semiconductive wafer which portion has been illuminated by the projected reticle image. In one embodiment a viewing port is formed in the mirror of a catadioptric lens by way of either a physical aperture or transmissive coatings. Off axis viewing of images through the viewing port is provided to provide telecentric images. Means are also provided for calibrating the position of the stage with respect to the reticle. Means are provided for determining offset values between the projected reticle image and the stage reference mark and for utilizing said offsets in controlling the position of the stage. A novel reticle alignment window array and alignment mark are disclosed which provide both direction and degree of misalignment information without the requirement of relative motion between the reticle and semiconductive wafer. Also employed is a subsystem which is responsive to the relative amounts of light being provided in the image of the alignment mark as a function of the proportion of the alignment mark being illuminated by the images of each of the alignment windows in the array so that a real-time alignment correction can be obtained.

Step-and-repeat alignment and exposure system and method therefore

Docking apparatus for a semiconductor wafer prober (16). A cylindrical housing assembly provides an electrical interface between pads on the wafer (22) and contacts on the load board (76) of a test head (12) through a contact ring (74). The housing assembly is in two parts with a first part (29) clamped to a frame portion (30) of the prober and a second part (58) supported above the first part by compression springs (64). Limited angular movement is provided between the housing assembly and the prober frame. The separation between the housing members is maintained so that the force exerted on the contact ring in the docking process is determined by the compression of the springs.

Docking apparatus

X-Y position measurement apparatus is employed with feedback controlled X-Y positioning apparatus for positioning a workpiece stage at a desired X-Y coordinate position in response to signals indicative of the actual position and the desired position of the workpiece stage. A normalization circuit is employed for gain correction of the signals indicative of the actual position of the workpiece stage.

Feedback-controlled workpiece positioning system

A step-and-repeat alignment and exposure system is provided with an adjustable holder for holding a main reticle, a main optical unit including a projection lens for producing an image of the main reticle at an image plane, a stage movable along coordinate axes adjacent to the image plane, and a holder rotatably mounted on the stage for holding a semiconductive wafer to be aligned with respect to the image of the main reticle. The system is further provided with an adjustable holder for holding an auxiliary reticle, a single channel auxiliary optical unit including a main objective lens for producing an image of the auxiliary reticle at the image plane, and a reference mark disposed on the stage and aligned with respect to the coordinate axes. The stage may be controlled for positioning the reference mark directly beneath either the projection lens or the main objective lens of the single channel auxiliary optical unit so that the images of both the main reticle and the auxiliary reticle may be aligned with respect to the reference mark and, hence, with respect to the coordinate axes, and so that the relative spacing between these images may be determined and checked from time to time. This permits the main optical unit and the auxiliary optical unit to be employed interchangeably in globally and precision region-by-region aligning the semiconductive wafer with respect to the coordinate axes prior to employing the projection lens in the photometric step-and-repeat printing of the image of the main reticle at each of an array of different regions on the semiconductive wafer. The system also includes a light source unit for selectively frontally illuminating the entire field of view of the main objective lens of the single channel auxiliary optical unit with white light not passing through the auxiliary reticle.

Step-and-repeat projection alignment and exposure system with auxiliary

An improved step and repeat alignment and exposure system for printing an image of a reticle onto a semiconductive wafer. A unit magnification catadioptric lens projects the reticle image onto the semiconductive wafer, and includes prisms to separate the image plane of the lens from the object plane. The semiconductive wafer is supported on stage means, which stage means provide motion in the X,Y directions. Viewing port means supplement the unit magnification catadioptric lens to provide a direct view of a portion of the semiconductive wafer which portion has been illuminated by the projected rectile image. A beam splitter is formed on a face of one of the prisms of the unit magnification catadioptric lens and is supplemented by an additional prism which provides optical path compatibility. A novel microscope structure is employed with large aperture focusing lenses to permit the infinity corrected objectives to translate about the field of view of the viewing port means without the requirement that any utilization device also translate in unison. Means are also provided for calibrating the position of the stage with respect to the reticle. Included are stage reference means which image a stage reference mark into the image plane of the unit magnification catadioptric lens when said stage reference means are illuminated by the projected reticle image. Means are provided for determining offset values between the projected reticle image and the stage reference mark and for utilizing said offsets in controlling the position of the stage. Further, means are provided for focusing and leveling the surface of the semiconductive wafer, wherein said means maintain, in a servo-controlled manner, said surface in a known position with respect to the stage. A six-degree of freedom support system is controlled by said focusing and leveling means to provide vertical position, pitch and roll movement of the semiconductive wafer.

A projection lens and a source of illumination and exposure light are employed for projecting an image of a reticle onto a first reference mark or a semiconductive wafer, both of which are movably supported in the image plane of the projection lens. Optical apparatus, including an objective lens unit and an imaging lens, is provided for imaging light from the source of illumination and exposure light at the reticle and for reimaging reflected light from the semiconductive wafer at the objective lens unit. Additional optical apparatus, including a source of nonexposure light, is provided and is operable with the projection lens for imaging a second adjustable reference mark onto the first reference mark or the semiconductive wafer to facilitate use of the projection lens in aligning a semiconductive wafer covered with a photoresist opaque to exposure light.

Bore-sighted step-and-repeat projection alignment and exposure system

A projection lens and a source of exposure light are employed for projecting an image of a reticle onto a first reference mark or a semiconductive wafer, both of which are movably supported in the image plane of the projection lens. Optical apparatus, including a source of nonexposure light and the projection lens, is provided for imaging a second adjustable reference mark onto the first reference mark or the semiconductive wafer to facilitate use of the projection lens in aligning a semiconductive wafer covered with a photoresist opaque to exposure light.

Growing community of inventors

Middletown, CA, United States of America

Edward H Phillips