Patent Description:
Prior to performing various processing operations on a semiconductor wafer, it may be necessary to determine the orientation of the semiconductor wafer. Some methods used to identify the orientation of the wafer can include providing a notch on a perimeter of the wafer, and utilizing a device to rotate the wafer such that the notch can be detected by a sensor in order to determine that the wafer is oriented at the desired orientation.

<CIT> discloses an apparatus comprising a base; a drive device disposed on the base, the drive device having an output shaft with a wafer receiving surface, the drive device being configured to rotate the output shaft about an axis of rotation; a sensor unit disposed on the base, the sensor unit being configured to sense a wafer received on the wafer receiving surface; and an engagement device configured to engage and disengage a translational mechanism between the drive device and the sensor unit,.

The present invention provides another apparatus according to independent claim <NUM>, and another method according to independent claim <NUM>. The dependent claims show further preferred embodiments of the said apparatus and method, respectively.

The present disclosure advantageously provides an apparatus comprising: a base; a drive device disposed on the base, the drive device having an output shaft with a wafer receiving surface, the drive device being configured to rotate the output shaft about an axis of rotation; a sensor unit disposed on the base, the sensor unit being configured to sense a wafer received on the wafer receiving surface; and an engagement device configured to engage and disengage a translational mechanism between the drive device and the sensor unit, wherein, when the engagement device engages the translational mechanism, rotation of the output shaft about the axis of rotation by the drive device changes a relative positional relationship between the sensor unit and the axis of rotation.

The present disclosure additionally advantageously provides a method comprising: providing an apparatus comprising: a base; a drive device disposed on the base, the drive device having an output shaft with a wafer receiving surface, the drive device being configured to rotate the output shaft about an axis of rotation; a sensor unit disposed on the base, the sensor unit being configured to sense a wafer received on the wafer receiving surface, and an engagement device configured to engage and disengage a translational mechanism between the drive device and the sensor unit; engaging the translational mechanism between the drive device and the sensor unit, and rotating the output shaft about the axis of rotation by the drive device to change a relative positional relationship between the sensor unit and the axis of rotation; and disengaging the translational mechanism between the drive device and the sensor unit, and rotating the output shaft about the axis of rotation by the drive device to rotate the wafer on the wafer receiving surface.

A more complete appreciation of the invention and many of the attendant advantages thereof will become readily apparent with reference to the following detailed description, particularly when considered in conjunction with the accompanying drawings, in which:.

Embodiments of the present invention will be described hereinafter with reference to the accompanying drawings. In the following description, the constituent elements having substantially the same function and arrangement are denoted by the same reference numerals, and repetitive descriptions will be made only when necessary.

A semiconductor wafer pre-alignment apparatus is described herein that advantageously accommodates various semiconductor wafer diameters.

Semiconductor wafers can be provided with a notch or marking that can be used to identify an orientation of the wafer, in order to ensure that the wafer is in a desired orientation for processing. For example, a single notch can be provided on a perimeter of the wafer. If a pre-alignment apparatus is provided with a wafer platform that supports and rotates the wafer, and a stationary read head that scans an edge of the wafer as it rotates, such an apparatus has distinct disadvantages. With such an apparatus, a range of a sensor of the read head may be only <NUM>, so the sensor must be positioned radially for different diameter wafers.

The semiconductor wafer pre-alignment apparatus described herein advantageously uses a same motor to both rotate the wafer and radially move the read head to allow for use with different sizes of wafers. In one embodiment of the apparatus, when the apparatus needs to radially move the read head, an actuator (such as an air cylinder or solenoid) drives a rack gear linearly towards a rotational gear. The rotational gear is rigidly affixed to the rotation motor. Once engaged, the motor can drive the rack and the read head to the appropriate radial position.

<FIG> depicts an apparatus <NUM> that can be used, for example, as a semiconductor wafer alignment apparatus to align a semiconductor wafer for inspection and/or for processing. The apparatus <NUM> can advantageously be used with semiconductor wafers having various diameters, as can be seen from concentric circles <NUM> shown in <FIG>.

The apparatus <NUM> includes a base <NUM>, a drive device <NUM>, a sensor unit <NUM>, and an engagement device <NUM>.

The base <NUM> shown in <FIG> includes a housing (or outer housing) <NUM> including an upper wall <NUM>, a lower wall <NUM>, a first side wall <NUM>, a second side wall <NUM>, a third side wall <NUM>, and a fourth side wall <NUM>. The upper wall <NUM> includes an opening <NUM> for a portion of the drive device <NUM> to extend therethrough. The upper wall <NUM> further includes a slot <NUM> for a portion of the sensor unit <NUM> to extend therethrough. The slot <NUM> allows for relative movement between the sensor unit <NUM> and the drive device <NUM>. The base <NUM> can either be mounted to a support in a stationary manner, for example, by fixing the base <NUM> with respect to a floor of a manufacturing facility, or in a movable manner, for example, by mounting the base <NUM> on a movable stage that can provide for movement with respect to the floor along one or more of an X axis, a Y axis, and a Z axis by using drive motors. The base <NUM> can be mounted by mounting the lower wall <NUM> to the support, or by mounting one of the other walls of the housing <NUM> to the support.

The drive device <NUM> is disposed on the base <NUM>. The drive device <NUM> has an output shaft <NUM> with a wafer platform <NUM> mounted to a distal end <NUM> of the output shaft <NUM>. The wafer platform <NUM> having a wafer receiving surface <NUM> that is configured to receive a semiconductor wafer. The wafer receiving surface <NUM> supports the wafer (see circles <NUM>), and can be provided with a surface material that provides friction between the wafer and the wafer receiving surface <NUM> to prevent the wafer from moving in relation to the wafer receiving surface <NUM>. Alternatively, or in addition to the surface material, the wafer receiving surface <NUM> can be provided with suction holes and the wafer platform <NUM> can be provided with a suction device to hold the wafer onto the wafer receiving surface <NUM> to prevent the wafer from moving in relation to the wafer receiving surface <NUM>. The wafer platform <NUM> can be fixed to the distal end <NUM> of the output shaft <NUM> such that the wafer platform <NUM> does not rotate relative to the output shaft <NUM>. Alternatively, the wafer platform <NUM> can be coupled to the distal end <NUM> such that the wafer platform <NUM> can selectively rotate relative to the output shaft <NUM> or not rotate relative to the output shaft <NUM>, for example, using a clutch configured to engage and disengage transmission of rotation of the output shaft <NUM> to rotation of the wafer platform <NUM>.

The drive device <NUM> is configured to rotate the output shaft <NUM> about an axis of rotation 302a. The drive device <NUM> can be, for example, an electric motor. The drive device <NUM> includes a housing <NUM> that is mounted to the housing <NUM>. In the embodiment shown in <FIG>, the housing <NUM> is mounted in a stationary manner to the upper wall <NUM>; however, the housing <NUM> could alternatively be mounted to another wall of the housing <NUM> of the base <NUM>. The drive device <NUM> includes a stator <NUM> that is mounted in a fixed relationship to the housing <NUM>, and a rotor <NUM> that rotates in relation to the stator <NUM>. The rotor <NUM> is supported via bearings <NUM> by a rotational support <NUM> that is mounted in a fixed relationship to the housing <NUM>. The output shaft <NUM> is part of or connected to the rotor <NUM> such that rotation of the rotor <NUM> results in rotation of the output shaft <NUM> about the axis of rotation 302a.

The output shaft <NUM> includes a lower portion <NUM> having a lower end <NUM>. A rotational member <NUM> is coupled to the lower end <NUM> of the output shaft <NUM>. The rotational member <NUM> can be fixed to the lower end <NUM> such that the rotational member <NUM> does not rotate relative to the output shaft <NUM>. Alternatively, the rotational member <NUM> can be coupled to the lower end <NUM> such that the rotational member <NUM> can selectively rotate relative to the output shaft <NUM> or not rotate relative to the output shaft <NUM>, for example, using a clutch configured to engage and disengage transmission of rotation of the output shaft <NUM> to rotation of the rotational member <NUM>.

The sensor unit <NUM> is disposed on the base <NUM>. The sensor unit <NUM> being configured to sense a wafer received on the wafer receiving surface <NUM>. The sensor unit <NUM> including a read head <NUM> having an optical sensor <NUM> facing in a -Z direction towards an upper surface of the wafer (see, e.g., <FIG> and <FIG>) that can sense the wafer, such as edges thereof or marks/notches formed thereon, within a sensing area <NUM> in order to align a semiconductor wafer for inspection and/or for processing. The read head <NUM> being mounted to a support member <NUM> that extends from within the housing <NUM> through the slot <NUM>.

The apparatus <NUM> includes a translational mechanism <NUM> between the drive device <NUM> and the sensor unit <NUM>. The translational mechanism <NUM> includes a carriage <NUM> that is slidably coupled the base <NUM>, and the sensor unit <NUM> is mounted on the carriage <NUM> via the support member <NUM>, which is mounted to the carriage <NUM>. In the embodiment shown in <FIG>, the housing <NUM> of the drive device <NUM> is mounted to the housing <NUM> of the base <NUM>, and first slide members <NUM> and <NUM> are mounted to opposing outer surfaces of the housing <NUM>. Alternatively, the first slide members <NUM> and <NUM> could be directly mounted to walls of the housing <NUM>. The carriage <NUM> includes second slide members <NUM> and <NUM> that are fixedly thereto. The second slide members <NUM> and <NUM> being slidably supported by the first slide members <NUM> and <NUM>, respectively, to allow the carriage <NUM> to slide along the X axis. In the embodiment shown in <FIG>, the first slide members <NUM> and <NUM> have respective slots <NUM> and <NUM> that longitudinally extending along the X axis, and the second slide members <NUM> and <NUM> are slide rails that are provided within the slots <NUM> and <NUM>, respectively; however, alternatively the second slide members <NUM> and <NUM> could be provided with slots that longitudinally extending along the X axis and the first slide members <NUM> and <NUM> could be slide rails that are provided within the slots.

The translational mechanism <NUM> further includes the rotational member <NUM> coupled to the output shaft <NUM>, and a linear member <NUM> connected to the carriage <NUM>. In the embodiment of <FIG>, the linear member <NUM> is a rack having a linear arrangement of teeth <NUM>. The linear member <NUM> is mounted on a bottom plate <NUM>, which is mounted to the second slide members <NUM> and <NUM> by flexures <NUM> and <NUM>, respectively. Thus, the linear member <NUM> is connected to the carriage <NUM> via the bottom plate <NUM> and the flexures <NUM> and <NUM>. Upper ends <NUM> and <NUM> of the flexures <NUM> and <NUM> are fixedly mounted to the second slide members <NUM> and <NUM>, and lower ends <NUM> and <NUM> of the flexures <NUM> and <NUM> are fixedly mounted to opposite side of the bottom plate <NUM>. The flexures <NUM> and <NUM> are flexible elements can bend when a cantilever force is applied to the lower ends <NUM> and <NUM> about the fixed upper ends <NUM> and <NUM>. The carriage <NUM>, the bottom plate <NUM>, and the flexure members <NUM> and <NUM> form a four-bar linkage.

The engagement device <NUM> is configured to engage and disengage the translational mechanism <NUM> between the drive device <NUM> and the sensor unit <NUM> such that, when the engagement device <NUM> engages the translational mechanism, rotation of the output shaft <NUM> about the axis of rotation 302a by the drive device <NUM> changes a relative positional relationship between the sensor unit <NUM> and the axis of rotation 302a, and thus change a relative positional relationship between the sensor unit <NUM> and the wafer receiving surface <NUM>. Also, when the engagement device <NUM> disengages the translational mechanism <NUM>, rotation of the output shaft <NUM> about the axis of rotation 302a by the drive device <NUM> does not change the relative positional relationship between the sensor unit <NUM> and the axis of rotation 302a.

The engagement device <NUM> includes an actuator <NUM> configured to move the linear member <NUM> into contact with an outer circumferential surface <NUM> of the rotational member <NUM> to engage the linear member <NUM> to the rotational member <NUM>. In the embodiment shown in <FIG>, the actuator <NUM> is configured to move the linear member <NUM> into contact with the outer circumferential surface <NUM> of the rotational member <NUM> to engage teeth <NUM> of the linear member <NUM> with teeth <NUM> on the outer circumferential surface <NUM> of the rotational member <NUM>.

In the embodiment shown in <FIG>, the actuator <NUM> is an air cylinder <NUM> that upon actuation extends piston rod <NUM> along the Y axis. The actuator <NUM> could alternatively be a solenoid. When the air cylinder <NUM> is not actuated, then the piston rod <NUM> is retracted by an internal biasing member along the Y axis, such as a spring. The air cylinder <NUM> has a first end <NUM> with a support member <NUM> that connects the first end <NUM> to a bracket <NUM>. The bracket <NUM> is mounted to the carriage <NUM> to maintain the first end <NUM> of the air cylinder in a fixed relationship with the carriage <NUM>. The piston rod <NUM> has a coupling member <NUM> mounted to a terminal end thereof. The coupling member <NUM> extends and retracts along the Y axis with the movement of the piston rod <NUM>. The coupling member <NUM> is coupled by a pin <NUM> to a connecting member <NUM> that is fixedly mounted to the bottom plate <NUM>.

Actuation of the actuator <NUM> bends the flexure members <NUM> and <NUM> to move the linear member <NUM> into contact with the outer circumferential surface <NUM> of the rotational member <NUM> to engage the linear member <NUM> to the rotational member <NUM>. Upon actuation of the actuator <NUM>, the air cylinder <NUM> extends piston rod <NUM> along the Y axis, thereby moving the coupling member <NUM> along the Y axis, which pushes bottom plate <NUM> via the pin <NUM> and connecting member <NUM>, thereby bending the flexure members <NUM> and <NUM> and moving the linear member <NUM> mounted to the bottom plate <NUM>. Thus, actuation of the actuator <NUM> moves the linear member <NUM> from a disengaged position in which the teeth <NUM> of the linear member <NUM> are not engaged to the teeth <NUM> of the rotational member <NUM> to an engaged position in which the teeth <NUM> of the linear member <NUM> are engaged to (i.e., meshed with) the teeth <NUM> of the rotational member <NUM>. Upon ceasing of the actuation of the actuator <NUM>, the air cylinder <NUM> retracts piston rod <NUM> along the Y axis (e.g. by force of the internal biasing member), thereby moving the coupling member <NUM> along the Y axis, which pulls bottom plate <NUM> via the pin <NUM> and connecting member <NUM>, thereby allowing the flexure members <NUM> and <NUM> to straighten and moving the linear member <NUM> mounted to the bottom plate <NUM>. The ceasing of the actuation moves the linear member <NUM> from the engaged position in which the teeth <NUM> of the linear member <NUM> are engaged to (i.e., meshed with) the teeth <NUM> of the rotational member <NUM> to the disengaged position in which the teeth <NUM> of the linear member <NUM> are not engaged to the teeth <NUM> of the rotational member <NUM>.

An amount of bending or deflection of the flexure members <NUM> and <NUM> can be determined, for example, based on a distance needed to move between an engaged state and a disengaged state of the teeth <NUM> and <NUM> (e.g. based on a height of the teeth <NUM> of the linear member <NUM> and a height of the teeth <NUM> of the rotational member <NUM>) and a predetermined clearance distance. In an embodiment in which no teeth are present, but rather a frictional engagement is used, then an amount of bending or deflection of the flexure members <NUM> and <NUM> can be determined, for example, based on a predetermined clearance distance.

When the linear member <NUM> is engaged to the rotational member <NUM> (i.e., when the linear member <NUM> is in the engaged position in which the teeth <NUM> of the linear member <NUM> are engaged to the teeth <NUM> of the rotational member <NUM>), then rotation of the output shaft <NUM> by the drive device <NUM> results in rotation of the rotational member <NUM>, which results in the teeth <NUM> of the rotational member <NUM> driving the teeth <NUM> of the linear member <NUM> in a direction along the X axis. Thus, the linear member <NUM>, the bottom plate <NUM>, the flexures <NUM> and <NUM>, and the carriage <NUM> are driven in the direction along the X axis such that the second slide members <NUM> and <NUM> slide along the first slide members <NUM> and <NUM>, respectively, to allow the carriage <NUM> and the sensor unit <NUM> to slide in the direction along the X axis. Therefore, when the linear member <NUM> is engaged to the rotational member <NUM>, the rotation of the output shaft <NUM> by the drive device <NUM> in clockwise and counterclockwise directions will result in translational movement of the sensor unit <NUM> along the X axis to change a relative positional relationship between the sensor unit <NUM> and the axis of rotation 302a by moving the sensor unit <NUM> closer to or farther away from the axis of rotation 302a, and thus change a relative positional relationship between the sensor unit <NUM> and the wafer receiving surface <NUM>. The change in the relative positional relationship between the sensor unit <NUM> and the axis of rotation 302a allows for the apparatus <NUM> to be used with a variety of different diameter semiconductor wafers, such that the relative positional relationship between the sensor unit <NUM> and the axis of rotation 302a can be adjusted so that the sensing area <NUM> of the optical sensor <NUM> can be aligned with an outer edge area of the wafer. Thus, the sensor unit <NUM> and the axis of rotation 302a can be adjusted to be closer to each other for use with wafers of smaller diameter, and the sensor unit <NUM> and the axis of rotation 302a can be adjusted to be farther from each other for use with wafers of larger diameter.

Conversely, when the linear member <NUM> is disengaged from the rotational member <NUM> (i.e., when the linear member <NUM> is in the disengaged position in which the teeth <NUM> of the linear member <NUM> are not engaged to the teeth <NUM> of the rotational member <NUM>), then rotation of the output shaft <NUM> by the drive device <NUM> will not result in the teeth <NUM> of the rotational member <NUM> driving the teeth <NUM> of the linear member <NUM> in a direction along the X axis. Therefore, when the linear member <NUM> is disengaged from the rotational member <NUM>, the rotation of the output shaft <NUM> by the drive device <NUM> in clockwise and counterclockwise directions will not result in translational movement of the sensor unit <NUM> along the X axis and thus does not change the relative positional relationship between the sensor unit <NUM> and the axis of rotation 302a. Thus, when the linear member <NUM> is disengaged from the rotational member <NUM>, the apparatus <NUM> can be used to perform alignment of the semiconductor wafer for inspection and/or for processing by using the drive device <NUM> to rotate the wafer and the optical sensor <NUM> to scan the wafer in the sensing area <NUM>.

In the embodiment depicted in <FIG>, the engagement device <NUM> is configured to engage and disengage a coupling <NUM> between the drive device <NUM> and the carriage <NUM>. The coupling <NUM> includes the rotational member <NUM> and the linear member <NUM>. When the rotational member <NUM> and the linear member <NUM> are engaged (i.e., when the linear member <NUM> is in the engaged position in which the teeth <NUM> of the linear member <NUM> are engaged to the teeth <NUM> of the rotational member <NUM>), then the drive device <NUM> and the carriage <NUM> are coupled together such that the rotation of the output shaft <NUM> by the drive device <NUM> in clockwise and counterclockwise directions will result in translational movement of the sensor unit <NUM> along the X axis to change a relative positional relationship between the sensor unit <NUM> and the axis of rotation 302a by moving the sensor unit <NUM> closer to or farther away from the axis of rotation 302a, and thus change a relative positional relationship between the sensor unit <NUM> and the wafer receiving surface <NUM>. Conversely, when the linear member <NUM> is disengaged from the rotational member <NUM> (i.e., when the linear member <NUM> is in the disengaged position in which the teeth <NUM> of the linear member <NUM> are not engaged to the teeth <NUM> of the rotational member <NUM>), then the drive device <NUM> and the carriage <NUM> are not coupled together such that the rotation of the output shaft <NUM> by the drive device <NUM> will not result in the teeth <NUM> of the rotational member <NUM> driving the teeth <NUM> of the linear member <NUM> in a direction along the X axis. Therefore, when the linear member <NUM> is disengaged from the rotational member <NUM>, the rotation of the output shaft <NUM> by the drive device <NUM> in clockwise and counterclockwise directions will not result in translational movement of the sensor unit <NUM> along the X axis and thus does not change the relative positional relationship between the sensor unit <NUM> and the axis of rotation 302a.

In the same manner as in the embodiment of <FIG>, <FIG> show an embodiment in which rotational member 322a is configured as a gear having an outer circumferential surface 324a with teeth 326a provided thereon. Additionally, linear member 440a is mounted on bottom plate 442a. The linear member 440a is configured as a rack having a linear arrangement of teeth 441a. <FIG> show the linear member 440a engaged to the rotational member 322a (i.e., the linear member 440a is in the engaged position in which the teeth 441a of the linear member 440a are engaged to the teeth 326a of the rotational member 322a). Therefore, in this engaged state, rotation of the rotational member 322a in the counterclockwise direction (as shown in <FIG>) will result in translational movement of the bottom plate 442a (as well as the connected carriage and sensor unit) along the X axis in a first direction 20a by sliding second sliding member 412a along first sliding member 330a. (For simplicity of the drawings, only one first sliding member and one second sliding member are shown in <FIG>; however, additional first and second sliding members can be included to provide stability to the sliding motion. ) Furthermore, in this engaged state, rotation of the rotational member 322a in the clockwise direction (as shown in <FIG>) will result in translational movement of the bottom plate 442a (as well as the connected carriage and sensor unit) along the X axis in a second direction 22a, which is opposite to the first direction 20a, by sliding second sliding member 412a along first sliding member 330a.

<FIG> show alternative embodiments of the invention.

<FIG> show an embodiment in which rotational member 322b is has an outer circumferential surface 324b that is frictionally engageable with a surface 441b of the linear member 440b. The outer circumferential surface 324b and/or the surface 441b can provided with surface material that provides friction between these surface when these surfaces are in contact with one another in order to prevent these surfaces from slipping in relation to one another when the rotational member 322b is rotated. <FIG> shows the linear member 440b engaged to the rotational member 322b (i.e., the outer circumferential surface 324b is in contact with the surface 441b). Therefore, in this engaged state, rotation of the rotational member 322b in the counterclockwise direction (as shown in <FIG>) will result in translational movement of the bottom plate 442b (as well as the connected carriage and sensor unit) along the X axis in a first direction 20b by sliding second sliding member 412b along first sliding member 330b. (For simplicity of the drawing, only one first sliding member and one second sliding member are shown in <FIG>; however, additional first and second sliding members can be included to provide stability to the sliding motion. ) Furthermore, in this engaged state, rotation of the rotational member 322b in the clockwise direction will result in translational movement of the bottom plate 442b (as well as the connected carriage and sensor unit) along the X axis in a second direction opposite to the first direction 20b, by sliding second sliding member 412b along first sliding member 330b.

<FIG> show an embodiment in which rotational member 322c is provided with a belt and pulley arrangement to transfer rotation of the rotational member 322c to translation of the sensor unit. Thus, the drive device includes pulleys 340c and 342c rotatably mounted to the housing of the drive device. The rotational member 322c has an outer circumferential surface 324c that drives a belt 344c about pulleys 340c and 342c. The belt 344c is fixed to member 440c, which is mounted on bottom plate 442c. In this embodiment, a clutch 323c is provided at the juncture between a lower end of the output shaft of the drive device and the rotational member 322c. The clutch 323c is configured to engage and disengage power transmission from the rotation of the output shaft to the rotation of the rotational member 322c. <FIG> show the member 440c engaged to the rotational member 322c due to an engaged state of the clutch 323c and presence of the belt 344c. Therefore, in this engaged state, rotation of the rotational member 322c in the counterclockwise direction (as shown in <FIG>) will result in translational movement of the bottom plate 442c (as well as the connected carriage and sensor unit) along the X axis in a first direction 20c by sliding second sliding member 412c along first sliding member 330c. (For simplicity of the drawings, only one first sliding member and one second sliding member are shown in <FIG>; however, additional first and second sliding members can be included to provide stability to the sliding motion. ) Furthermore, in this engaged state, rotation of the rotational member 322c in the clockwise direction (as shown in <FIG>) will result in translational movement of the bottom plate 442c (as well as the connected carriage and sensor unit) along the X axis in a second direction 22c, which is opposite to the first direction 20c, by sliding second sliding member 412c along first sliding member 330c.

The clutch described above and below can be any conventional clutch that allows for engagement and disengagement of power transmission from the rotation of the output shaft to the rotation of the rotational member. It is noted that a clutch, such as is described above with respect to <FIG>, could be incorporated into any of the embodiments shown in <FIG> as the engagement device <NUM>, thereby eliminating the need for actuator <NUM> and eliminating the need for movement of the bottom plate in the direction of the Y axis. Thus, the rotational member and the linear member can remain in an engaged state, and the clutch can be used to engage or disengage power transmission from the rotation of the output shaft to the rotation of the rotational member and thus engage or disengage power transmission of the output shaft from rotating the rotational member and thus driving the movement of the linear member. Additionally, in such a configuration, the flexures could be made of a more rigid material.

<FIG> show an embodiment in which rotational member 322d is provided with a member 340d fixedly connected to the rotational member 322d. The member 340d can extend from an outer circumferential surface 424d of the rotational member 322d as shown or can be provided on an outer edge of the rotational member 322d at a location spaced apart from the axis of rotation of the rotational member 322d. The member 340d is pivotally connected to an arm member 342d by a first pivot joint 344d. The arm member 342d is pivotally connected to member 440d by a second pivot joint 346d to provide a linkage between the rotational member 322d and the member 440d. The member 440d is mounted on bottom plate 442d. In this embodiment, a clutch 323d is provided at the juncture between a lower end of the output shaft of the drive device and the rotational member 322d. The clutch 323d is configured to engage and disengage power transmission from the rotation of the output shaft to the rotation of the rotational member 322d. <FIG> show the member 440d engaged to the rotational member 322d due to an engaged state of the clutch 323d and presence of the linkage including arm member 342d. Therefore, in this engaged state, rotation of the rotational member 322d in the clockwise direction (as shown in <FIG>) will result in translational movement of the bottom plate 442d (as well as the connected carriage and sensor unit) along the X axis in a first direction 20d by sliding second sliding member 412d along first sliding member 330d. (For simplicity of the drawings, only one first sliding member and one second sliding member are shown in <FIG>; however, additional first and second sliding members can be included to provide stability to the sliding motion. ) Furthermore, in this engaged state, rotation of the rotational member 322d in the counterclockwise direction (as shown in <FIG>) will result in translational movement of the bottom plate 442d (as well as the connected carriage and sensor unit) along the X axis in a second direction 22d, which is opposite to the first direction 20d, by sliding second sliding member 412d along first sliding member 330d.

<FIG> shows an embodiment in which rotational member 322e is provided with a drive arm 340e fixedly connected to the rotational member 322e and extending from an outer circumferential surface 424e of the rotational member 322e. The drive arm 340e having an elongated shape with a cam slot 342e extending longitudinally along the drive arm 340e. A cam follower 344e is fixedly mounted on member 440e. The member 440e is mounted on bottom plate 442e which is connected to the carriage via the flexures. The cam follower 344e disposed within the cam slot 342e such that pivoting motion of the drive arm 340e due to rotation of the rotational member 322e cause the cam follower 344e to be driven in the X axis direction by the cam slot 342e. In this embodiment, a clutch 323e is provided at the juncture between a lower end of the output shaft of the drive device and the rotational member 322e. The clutch 323e is configured to engage and disengage power transmission from the rotation of the output shaft to the rotation of the rotational member 322e. <FIG> shows the member 440e engaged to the rotational member 322e due to an engaged state of the clutch 323e and presence of drive arm 340e, cam slot 342e and cam follower 344e. Therefore, in this engaged state, rotation of the rotational member 322e in the counterclockwise direction (as shown in <FIG>) will result in translational movement of the bottom plate 442e (as well as the connected carriage and sensor unit) along the X axis in a first direction 20e by sliding second sliding member 412e along first sliding member 330e. (For simplicity of the drawing, only one first sliding member and one second sliding member are shown in <FIG>; however, additional first and second sliding members can be included to provide stability to the sliding motion. ) Furthermore, in this engaged state, rotation of the rotational member 322e in the clockwise direction will result in translational movement of the bottom plate 442e (as well as the connected carriage and sensor unit) along the X axis in a second direction opposite to the first direction 20e, by sliding second sliding member 412e along first sliding member 330e.

The apparatus of the present invention advantageously provides a drive device that can be used both to rotate a semiconductor wafer about an axis of rotation and to adjust a positional relationship between a sensor unit and the axis of rotation. The adjustment of the positional relationship between the sensor unit and the axis of rotation advantageously allows the apparatus to be used with various sizes of semiconductor wafers with a wide range of diameters.

With respect to the embodiment shown in <FIG>, the apparatus <NUM> can be utilized, for example, by placing a semiconductor wafer on the wafer receiving surface <NUM> of the wafer platform <NUM>, engaging the engagement device <NUM> by actuating actuator <NUM> to bend flexures <NUM> and <NUM> to engage teeth <NUM> with teeth <NUM>, actuate the drive device <NUM> to rotate the output shaft <NUM> and the rotational member <NUM> in order to drive the carriage <NUM> and sensor unit <NUM> in a direction along the X axis toward the axis of rotation 302a, and utilize the optical sensor <NUM> to detect the presence or absence of the semiconductor wafer in the sensing area <NUM>. Once the optical sensor <NUM> detects the presence of an edge of the semiconductor wafer move within the sensing area <NUM>, then the drive device <NUM> and/or the engagement device <NUM> can be deactivated to stop the movement of the carriage <NUM> and sensor unit <NUM> in the direction along the X axis toward the axis of rotation 302a. Once the optical sensor <NUM> is at a desired position with respect to the semiconductor wafer on the wafer receiving surface <NUM>, then the apparatus <NUM> can be used to perform alignment of the semiconductor wafer for inspection and/or for processing by using the drive device <NUM> to rotate the wafer and the optical sensor <NUM> to scan the wafer in the sensing area <NUM>.

The apparatus <NUM> advantageously allows for adjustment of the relative positional relationship between the sensor unit <NUM> and the axis of rotation <NUM> using a same drive device used to rotate the semiconductor wafer about the axis of rotation. The change in the relative positional relationship between the sensor unit <NUM> and the axis of rotation 302a allows for the apparatus <NUM> to be used with a variety of different diameter semiconductor wafers, such that the relative positional relationship between the sensor unit <NUM> and the axis of rotation 302a can be adjusted so that the sensing area <NUM> of the optical sensor <NUM> can be aligned with an outer edge area of the wafer. Thus, the sensor unit <NUM> and the axis of rotation 302a can be adjusted to be closer to each other for use with wafers of smaller diameter, and the sensor unit <NUM> and the axis of rotation 302a can be adjusted to be farther from each other for use with wafers of larger diameter.

<FIG> depicts an embodiment of a clutch <NUM> that is configured to engage and disengage power transmission from rotation of the output shaft <NUM> of the drive device <NUM> to rotation of a rotational member <NUM>, and engage and disengage power transmission from the rotation of the output shaft <NUM> of the drive device <NUM> to the linear member <NUM> engaged to the rotational member <NUM>. Clutch <NUM> can be used with rotational member <NUM> configured as a gear having an outer circumferential surface <NUM> with teeth provided thereon, and a linear member <NUM> configured as a rack having a linear arrangement of teeth <NUM>, as contemplated by the depiction in <FIG>. Alternatively, clutch <NUM> could be used as a clutch with any of the other embodiments shown herein.

The clutch <NUM> includes a drive device <NUM> that is configured to drive a shaft <NUM> upon which the rotational member <NUM> is mounted in the Z direction. For example, the drive device <NUM> could be an air cylinder, solenoid, etc. that drives the shaft <NUM> in a linear direction and that passively allows rotation of the shaft <NUM>, so that the rotational member <NUM> can be driven in rotation by the drive device <NUM> when the rotational member <NUM> is engaged to the output shaft <NUM>. The lower end <NUM> of the output shaft <NUM> has a disk 320a with a lower engagement surface <NUM>. When the drive device <NUM> is actuated to drive the shaft <NUM> in the Z direction, then an upper engagement surface <NUM> of the rotational member <NUM> contacts and thus engages (e.g., frictionally, using grooves, teeth, etc.) the lower engagement surface <NUM>, and once the drive device <NUM> is no longer actuated then the drive shaft <NUM> will move in the -Z direction and the rotational member <NUM> will disengage from the output shaft <NUM>. It is noted that the amount of movement of the shaft <NUM> in order to perform this engagement can be small, and is exaggerated in <FIG> for purposes of illustration. During this Z direction movement, the teeth on the outer circumferential surface <NUM> can slide with respect to teeth <NUM>, and the components can slide or flex (e.g., belt 344c, member 340d, arm member 342d) in relation to one another in the other embodiments in order to allow for this small relative movement.

In order to allow for the movement of the shaft <NUM>, the shaft <NUM> can be rotationally mounted using bearing <NUM>. An outer periphery of the bearing <NUM> can be rigidly mounted to the drive device <NUM> by mounting bracket <NUM> that is mounted to lower wall <NUM> as shown or can be rigidly mounted directly to the lower wall <NUM>. An inner periphery of the bearing <NUM> is slidably engaged to slides <NUM> that are fixed to the shaft <NUM>, in order to allow movement of the shaft <NUM> along the Z axis and also allow rotation of the shaft <NUM> about the Z axis.

<FIG> illustrates an embodiment of a computer <NUM> with which an embodiment of the invention may be implemented. Although computer <NUM> is depicted with respect to a particular device or equipment, it is contemplated that other devices or equipment (e.g., network elements, servers, etc.) within <FIG> can deploy the illustrated hardware and components of system <NUM>. The computer <NUM> is programmed (e.g., via computer program code or instructions) to provide the functionality described herein and includes a communication mechanism such as a bus <NUM> for passing information between other internal and external components of the computer system <NUM>. One or more processors <NUM> for processing information are coupled with the bus <NUM> to perform a set of operations on information as specified by computer program code.

The computer <NUM> also includes a memory <NUM> coupled to bus <NUM>. The memory <NUM>, such as a random access memory (RAM) or other dynamic storage device, stores information including processor instructions. The memory <NUM> is also used by the processor <NUM> to store temporary values during execution of processor instructions. The computer system <NUM> also includes a read only memory (ROM) <NUM> or other static storage device coupled to the bus <NUM> for storing static information, including instructions, that is not changed by the computer system <NUM>. The computer <NUM> includes a communication interface <NUM> that allows the computer <NUM> to communicate with other devices or equipment (e.g., network elements, servers, etc.).

Information, including user input instructions, is provided to the bus <NUM> for use by the processor <NUM> from a user interface <NUM>, such as a keyboard containing alphanumeric keys operated by a human user, a display device, a pointing device (such as a mouse or a trackball or cursor direction keys).

A drive device <NUM> (e.g., drive device <NUM>) can communicate with the processor <NUM> via the bus <NUM> in order to send and receive data, operating instructions/commands, or other information therebetween. The processor <NUM> can control operation of the drive device <NUM> using operating instructions/commands in order to control rotation (e.g., start, stop, direction (e.g., clockwise, counterclockwise), speed, etc.) of an output shaft (such as output shaft <NUM>) of the drive device <NUM>.

An engagement device <NUM> (e.g. actuator <NUM>, clutch 323c, clutch 323d, clutch 323e, etc.) can communicate with the processor <NUM> via the bus <NUM> in order to send and receive data, operating instructions/commands, or other information therebetween. The processor <NUM> can control operation of the engagement device <NUM> using operating instructions/commands in order to control actuation of the engagement device <NUM>.

An optical sensor <NUM> (e.g. optical sensor <NUM>) can communicate with the processor <NUM> via the bus <NUM> in order to send and receive data, operating instructions/commands, or other information therebetween. The processor <NUM> can control operation of the optical sensor <NUM> using operating instructions/commands in order to control operation of the optical sensor <NUM> in conjunction with the operation of the drive device <NUM> and/or the engagement device <NUM>.

For example, as noted above, a semiconductor wafer can be placed on a wafer receiving surface of a wafer platform, the processor <NUM> (either using instructions entered by a user via the user interface <NUM> or instructions stored in memory <NUM>) sends a command to the engagement device <NUM> to actuate, the processor <NUM> (either using instructions entered by a user via the user interface <NUM> or instructions stored in memory <NUM>) sends a command to the drive device <NUM> to rotate the output shaft in order to drive the optical sensor <NUM> in a direction along the X axis toward the axis of rotation, and the processor <NUM> (either using instructions entered by a user via the user interface <NUM> or instructions stored in memory <NUM>) sends a command to the optical sensor <NUM> to detect the presence or absence of the semiconductor wafer. Once the optical sensor <NUM> detects the presence of an edge of the semiconductor wafer move within the sensing area and sends such data to the processor <NUM>, then the processor <NUM> sends commands to the drive device <NUM> and/or the engagement device <NUM> to deactivate to stop the movement of the optical sensor <NUM> in the direction along the X axis toward the axis of rotation. Once the optical sensor <NUM> is at a desired position with respect to the semiconductor wafer on the wafer receiving surface, then the process <NUM> can perform alignment of the semiconductor wafer for inspection and/or for processing by using the drive device <NUM> to rotate the wafer and the optical sensor <NUM> to scan the wafer in the sensing area.

Claim 1:
An apparatus (<NUM>) comprising:
a base (<NUM>);
a drive device (<NUM>) disposed on the base (<NUM>), the drive device (<NUM>) having an output shaft (<NUM>) with a wafer receiving surface (<NUM>), the drive device (<NUM>) being configured to rotate the output shaft (<NUM>) about an axis of rotation (302a);
a sensor unit (<NUM>) disposed on the base (<NUM>), the sensor unit (<NUM>) being configured to sense a wafer received on the wafer receiving surface (<NUM>); and
an engagement device (<NUM>) configured to engage and disengage a translational mechanism (<NUM>) between the drive device (<NUM>) and the sensor unit (<NUM>),
wherein the apparatus (<NUM>) is characterized in that:
when the engagement device (<NUM>) engages the translational mechanism (<NUM>), rotation of the output shaft (<NUM>) about the axis of rotation (302a) by the drive device (<NUM>) changes a relative positional relationship between the sensor unit (<NUM>) and the axis of rotation (302a).