WO2008057567A2

WO2008057567A2 - Vacuum end effector for handling highly shaped substrates

Info

Publication number: WO2008057567A2
Application number: PCT/US2007/023465
Authority: WO
Inventors: Preston X. Whitcomb; Ulrich Marckmann
Original assignee: Integrated Dynamics Engineering, Inc.
Priority date: 2006-11-07
Filing date: 2007-11-07
Publication date: 2008-05-15
Also published as: US20080107509A1; WO2008057567A3

Abstract

The present teachings relate to a system for handling semiconductor substrates with end effector devices. In one embodiment a plurality of orifices situated on a robot end effector are used to manipulate a highly shaped semiconductor wafer or substrate. The orifices may create vacuum forces on the substrate to enable the handling of the substrate. An end effector may have one or more primary orifices and may have one or more additional secondary orifices. The one or more primary orifices may be controllable and may have a high vacuum flow, greater than about 1 ft3/min.

Description

VACUUM END EFFECTOR FOR HANDLING HIGHLY SHAPED SUBSTRATES

FIELD OF INVENTION [0001] This invention relates to the field of robotics, and specifically to vacuum

end effectors for handling highly shaped substrates such as warped or bowed silicon

wafers.

BACKGROUND [0002] As semiconductor technology advances to construct more sophisticated

products, so does the process involved in the fabrication of the semiconductor

devices. In today's marketplace there is a continuous demand to shrink

semiconductor wafers or substrates and at the same time increase the device's

transistor density. As the device's density increases, the device produces more heat,

which must be conducted away from the device to improve performance. The need

for rapid heat conduction has lead to a thinning of the semiconductor substrate

through various methods such as back grinding. The process of thinning the back

surface of the substrate along with the stress induced by the film materials on the

front surface of the substrate has resulted in highly shaped substrates that are

increasing difficult to handle.

[0003] An end effector is the device at the end of a robotic arm designed to

interact with its environment. The exact nature of this device depends on the

application of the robot. The end effector of an assembly line robot would typically

be a welding head or a spray gun. A surgical robot's end effector could be a scalpel

or others tools used in surgery. Other possible end effectors are machining tools, such as drills or milling cutters. For example, the end effector on a space shuttle's robotic arm uses a pattern of wires which close like the aperture of a camera around a handle or other grasping point.

[0004] Typically, in semiconductor fabrication a robotic system employs an end effector to safely move a semiconductor substrate to the various points and positions required to process the substrate. A vacuum end effector involves the use of a vacuum to pick up and transport objects or substrates. For example, a robot may include a vacuum end effector to capture a substrate, transfer and place the substrate into a processing chamber, and then transfer the substrate back into a storage area after processing is complete.

[0005] A semiconductor substrate may be a wafer, e.g., a silicon wafer. FIGS. IA and IB depict flat substrates. When the wafers are thinned and/or highly shaped, present day vacuum end effectors are rendered unreliable. A highly shaped substrate can be, for example, a bowed substrate (as shown in FIGS. 1C and ID) or a warped substrates (as shown in FIGs. IE and IF). The substrates or wafers can be 4, 6, 8, or 12 inch silicon wafers. In some embodiments, the substrate can be square, round, rectangular, oval, or oblong. Present day vacuum end effectors have difficulty handling and transporting these highly shaped substrates because the vacuum end effectors are unable to make a tight seal with the highly shaped substrate. Therefore, a need exists to modify vacuum end effectors so that they can successfully transport highly shaped substrates. SUMMARY OF THE INVENTION

[0006] In satisfaction of this need and others, the present invention relates devices and methods for handling highly shaped substrates. In one aspect, the present invention relates to a device for handling highly shaped substrates comprising an end effector having a first side and a second side, the first side being a planar surface and having a first primary vacuum orifice in the planar surface for applying a vacuum force, and a sensor for sensing a level of contact between the substrate and the end effector, wherein the vacuum force through the first primary orifice is regulated by the sensing of the sensor. In some embodiments, the device can include one or more secondary vacuum orifice in the planar surface or in a second side of the planar surface. In various embodiments, the end effector can be a fork, a paddle, or a ring. In some embodiments, the end effector can include a second primary vacuum orifice, a primary orifice located in the second side of the planar surface, and/or an embedded capacitance sensor. In some embodiments the sensor can measure the back pressure in the first vacuum orifice. The device can further include a robot arm connected to the end effector and a vacuum conduit system in fluid communication with the end effector. In various embodiments, the vacuum conduit system can be external to the end effector or internal to the end effector. The system can have an umbilical cord configuration and/or can be flexible.

[0007] Another embodiment of the present invention relates to a device including an end effector having a first side and a second side, the first side including a planar surface and having a first primary vacuum orifice in the planar surface for applying a vacuum force and a back pressure sensor disposed on the end effector for sensing a level of contact between the substrate and the end effector. The back pressure sensor can be a diaphragm pressure sensor.

[0008] Another embodiment of the present invention relates to a device including an end effector having plurality of vacuum orifices, each of the vacuum orifices applying a vacuum force and a plurality of vacuum valves, each of the vacuum valves modulating the vacuum force through one of the plurality of vacuum orifices. The vacuum valve can be a solenoid valve or a proportional pneumatic valve.

[0009] Another embodiment of the present invention relates to a device including an end effector having a first side and a second side, the first side including a planar surface and having a first primary vacuum orifice in the planar surface for applying a vacuum force to a substrate and a sensor disposed on the end effector for sensing a level of contact between the substrate and the end effector, wherein the vacuum force of the first primary orifice is greater than about 1 ftVmin.

[0010] Another aspect of the present invention relates to a method of capturing a highly shaped substrate including positioning an end effector in proximity to a highly shaped substrate, applying a vacuum force through a first vacuum orifice in the end effector, and capturing the substrate with the vacuum force. In various embodiments, the method can further include rotating the end effector to capture the substrate, detecting contact between the substrate and the orifice through analog sensing of back pressure, modulating the vacuum force through an analog signal, and/or vibrating the end effector to capture the substrate, wherein the vibrating and the modulating of the end effector is performed at the resonance frequency of the substrate. In some embodiments, the vacuum force is applied at the resonance frequency of the substrate and can be modulated through an analog signal. In some embodiments, the contact is detected through an embedded capacitance sensor. In certain embodiments, the contact between the substrate and the end effector is detected by analog sensing of the back pressure in the vacuum orifice. In some embodiments, the position of the substrate relative to the vacuum orifice can be detected by an embedded capacitance sensor or through analog sensing of back pressure. In certain embodiments, the method can further include turning off the vacuum force in the first vacuum orifice and applying another vacuum force to a second vacuum orifice in the end effector.

[0011] Another embodiment of the present invention relates to a method for handling a highly shaped substrate including positioning near a substrate an end effector having a plane and a plurality of vacuum orifices, each vacuum orifice having a vacuum force, deforming the substrate with the vacuum force from a first vacuum orifice of the plurality of vacuum orifices into the plane of the end effector, and capturing the substrate with the vacuum force of a second vacuum orifice of the plurality of vacuum orifices.

[0012] Another embodiment includes positioning an end effector having a vacuum orifice near a substrate, modulating a vacuum force through the vacuum orifice at about the resonant frequency of the substrate, sensing the displacement of the substrate for modulating of the vacuum force, and capturing the substrate based on the sensing of the displacement of the substrate. In some embodiments sensing the displacement of the substrate includes sensing back pressure in the vacuum orifice or measuring capacitance.

[0013] Another embodiments relates to a method of determining the resonant frequency of a substrate including applying a vacuum force to the substrate, modulating the vacuum force over a range of frequencies, sensing a displacement of the substrate, and determining the resonant frequency of the substrate to be the frequency at which the greatest displacement of the substrate occurs.

BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIG. IA is a side view of a flat substrate.

[0015] FIG. IB is perspective view of a flat substrate.

[0016] FIG. 1C is a side view of a bowed substrate.

[0017] FIG. ID is perspective view of a bowed substrate.

[0018] FIG. IE is a side view of a warped substrate.

[0019] FIG. IF is a perspective view of a warped substrate.

[0020] FIG. 2A is a top view of a forked end effector and a robot arm according to an embodiments of the present invention.

[0021] FIG. 2B is a top view of tine of the forked end effector of FIG. 2 A, according to an embodiment of the present invention. [0022] FIG. 3 A is a top view of a paddle end effector having three secondary orifices and one primary orifice, according to an embodiment of the present invention.

[0023] FIG. 3B is a top view of a paddle end effector having three primary orifices, according to an embodiment of the present invention.

[0024] FIG. 3C is a top view of a ring end effector having four primary orifices, according to an embodiment of the present invention.

[0025] FIG. 4 is a top view of a forked end effector having two main orifices, one on each tine, and on primary orifice, according to an embodiment of the present invention.

[0026] FIG. 5 A is perspective view of an end effector approaching a highly shaped substrate from below the substrate, according to an embodiment of the present invention.

[0027] FIG. 5B is a depiction of the end effector of FIG. 5 A capturing one end of the substrate, according to an embodiment of the present invention.

[0028] FIG. 5C is a depiction the end effector of FIG. 5 A capturing the remainder of the substrate and straightening the substrate, according to an embodiment of the present invention.

[0029] FIG. 6 is a high level flow chart depicting a method of capturing highly shaped substrates, according to an embodiment of the present invention. [0030] FIG. 7 is a depiction of vacuum conduit system, according to an embodiment of the present invention.

[0031] FIG. 8A is a depiction of a vacuum end effector with embedded capacitance sensors, according to an embodiment of the present invention.

[0032] FIG. 8B is a depiction of a vacuum end effector with offset capacitance sensors, according to an embodiment of the present invention.

[0033] FIG. 9 is a high level flow chart depicting another method of capturing highly shaped substrates, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION [0034] The present invention relates to a vacuum end effector for capturing and transporting highly shaped substrates. The vacuum end effector may have at least one controllable non-restrictive primary orifice connected to a vacuum system. The primary orifice may have a high vacuum flow rate of greater than about 1 ft³/min. The vacuum flow through the primary orifice can be regulated and the level of contact between the substrate and the end effector can be measured or sensed. In addition, the end effector may have one or more secondary orifices, which also are connected to a vacuum system. Based on the feedback from the one or more primary orifices, the vacuum applied to each primary orifice can be altered in order to firmly grasp and capture the substrate. At the same time, the system provides air flow and vacuum forces to one or more secondary orifice(s). These secondary orifices are constructed to restrict the vacuum flow and are open to atmosphere, but do not affect the primary orifice in any relevant manner. The robotic arm attached to the end effector also can rotate and move in three directions and the end effector can use vibration to grasp the substrate. A conduit system that provides maximum flow to one or more primary orifice(s) of consistent diameter and shape is employed in conjunction with the robot arm and the end effector.

[0035] Throughout the description, where devices or compositions are described as having, including, or comprising specific components, or where processes are described as having, including, or comprising specific process steps, it is contemplated that compositions of the present teachings also consist essentially of, or consist of, the recited components, and that the processes of the present teachings also consist essentially of, or consist of, the recited processing steps. It should be understood that the order of steps or order for performing certain actions is immaterial so long as the method remains operable. Moreover, two or more steps or actions can be conducted simultaneously.

[0036] In the application, where an element or component is said to be included in and/or selected from a list of recited elements or components, it should be understood that the element or component can be any one of the recited elements or components and can be selected from two or more of the recited elements or components. Further, it should be understood that elements and/or features of a composition, an apparatus, or a method described herein can be combined in a variety of ways without departing from the spirit and scope of the present invention, whether explicit or implicit herein. [0037] It is to be understood that the figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the present teachings while eliminating, for purposes of clarity, other elements.

[0038] The use of the terms "include," "includes," "including," "have," "has," or "having" should be generally understood as open-ended and non-limiting unless specifically stated otherwise.

[0039] The use of the singular herein includes the plural (and vice versa) unless specifically stated otherwise. In addition, where the use of the term "about" is before a quantitative value, the present teachings also include the specific quantitative value itself, unless specifically stated otherwise.

[0040] FIG. 2 A is a top-view of a robotic arm 10 and a vacuum end effector 12, according to the present invention. The robotic arm 10 may have three degrees of freedom with Selective Compliance Articulated Robot Arm ("SCARA") kinematics. This type of robot has three joints in the horizontal plane that give it x-y positioning and orientation parallel to the plane. One linear joint supplies the z positioning. This is the typical "pick and place" robot. The three directions of movement are R (distance), θ (angle), and Z (elevation). In another embodiment, the robotic arm 10 has four degrees of freedom with SCARA kinematics. The four direction of movement may be R (distance), θ (angle), Z (elevation) and an additional wrist rotation axis. The wrist rotation axis permits rotation of the end effector 12 relative to the wafer plane mechanically for improved contact between the end effector 12 and the substrate. In another embodiment, the robotic arm 10 can have six degrees of freedom: X, Y, θ , Z, roll and pitch.

[0041] An end effector is connected to the robot arm and is used to capture highly shaped substrates. End effectors, according to the present invention, may have three holding points. For example, an end effector with one primary orifice will have two secondary orifices. An end effector with two primary orifices will have one secondary orifice, and if there are at least three primary orifices, there might not be any secondary orifices. The end effector may have more than three total orifices, including all primary orifices, as well.

[0042] In another embodiment, the end effector has one primary orifice having a high vacuum flow to enable the end effector to distort and capture a highly shaped substrate. The high vacuum flow can range from about 1 ftVmin to about 3 ft³/min. This high vacuum flow results in a high vacuum force through the primary orifice. Such a high vacuum force may enable the end effector to distort the highly shaped substrate into a plane of or defined by the end effector for effective handling of the substrate. This distortion can bend a bowed or warped substrate within reach of the vacuum orifice or can pull the substrate closer to the end effector.

[0043] With continued reference to FIG. 2A, in one embodiment, the end effector 12 is a fork with a right portion 14 and a left portion 16. The fork can be machined from a single piece of aluminum. Both the right portion 14 and the left portion of the fork 16 each may have one surface with vacuum orifices. The end effector 12 may contain one primary orifice 18, located at the center of the fork, and a first secondary orifice 19, located on the right portion of the fork 14 and a second secondary orifice 20 located on the left the fork 16. The primary and secondary orifices can be circular openings in the end effector, to which a vacuum is applied. Both the primary and secondary orifices are machined and are integral to the end effector. The primary orifice is designed for maximum air flow and is a sensing and controllable orifice. As detailed below, the vacuum flow to the primary orifice may be turned on and off, may be modulated, and may be used to sense the proximity of the vacuum end effector to the substrate.

[0044] FIG. 2B shows the secondary orifices in more detail. Each secondary orifice 20 comprises several individual orifices, 2OA, 2OB, 2OC, and 2OD. The secondary orifices are restrictive, are not controllable, and the vacuum to the secondary orifices cannot be turned on and off like the primary orifices. Instead, the secondary orifices are designed for restricted air flow. The secondary orifices may limit the flow of air so as to not affect the primary orifice's air flow and vacuum forces. In another embodiment, the secondary orifices may be machined slots (as shown in FIG. 2B), instead of circular openings. The slots may be sized to allow only a small amount of air flow when open to the atmosphere. The slots also may be sized to provide a significant holding force when in contact with a surface that throttles the flow. Through both the primary and secondary orifices, the vacuum end effector may allow for vacuum flow of more than about 1 ft³/min, preferably in the range of about 1 ftVmin to about 2 ft³/min.

[0045] In another embodiment, each surface of the fork, i.e., a top surface and a bottom surface may have one or more vacuum orifices. In this embodiment, the end effector may have two primary orifices, one on the top surface and one on the bottom surface, and two sets of two secondary orifices, one set on the top surface and the other set on the bottom surface. This permits two distinct and controllable configurations in one end effector.

[0046] In other embodiments, the end effector can be one of numerous shapes other than a fork including a paddle and a ring. FIG. 3A depicts a paddle configuration 22. The paddle comprises one primary orifice 24 and three secondary orifices, 25, 26, and 27. All of the orifices may be located on a single side of the paddle 22, or the orifices may be located on both sides of the paddle 22.

[0047| In other embodiments, the end effector may have more than one primary orifice, for example, three or more controllable and sensing primary orifices. The more orifices located on the end effector, the better the chance to capture the substrate. However, there is a physical limit because of space constraints on the end effector and pneumatic losses. The placement of the orifices on the end effector can be a function of the substrates and the support provided to the substrates at the stations where the substrates are waiting to be transported.

[0048] As discussed below, the vacuum forces associated with each primary orifice may be used to capture and manipulate the substrate. To facilitate capture of the substrate, each primary orifice may be selectively turned on and off. For example, the vacuum force of one primary orifice can deform the substrate into the plane associated with the vacuum end effector. This deformation of the substrate allows the other primary orifices to vacuum seal to the substrate. The vacuum seal of the several orifices may allow sufficient holding support to permit the rotation of the substrate. Once supported, the substrate may be rotated forty five, ninety, one hundred and eighty, or up to three hundred and sixty degrees while grasped by the vacuum end effector.

[0049] FIG. 3B depicts another embodiment of the present invention, a paddle 22 with three primary orifices 28, 30, and 32. The orifices may be located on a single side of the paddle 22, or may be located on both sides of the paddle 22.

[0050] FIG. 3C depicts another embodiment of the present invention, a ring end effector 34. The ring 34 comprises four primary orifices 36, 38, 40, and 42. The orifices may be located on a single side of the ring 34, or may be located on both sides of the ring 34. Each fork, paddle, or ring has at least one primary orifice and may have one or more primary orifices.

[0051] FIG. 4 depicts another embodiment of the present invention. FIG. 4 depicts a fork end effector 43, having a first primary orifice 44, a second primary orifice 46, and one secondary orifice 48.

[0052] Another aspect of the present invention relates to a method of capturing highly shaped substrates. In order to capture the highly shaped substrate, the end effector must create a vacuum seal with at least one of its multiple orifices. Once the first seal is made, the substrate can be manipulated and/or straightened to permit a vacuum seal with the other orifices. Once a tight seal has been made between the substrate and the end effector, the substrate can be safely transported.

[0053] In order to create the initial vacuum seal with one of the orifices, the end effector may rotate or lift the fork, paddle, or ring in the proximity of the substrate. For example, if the end effector has a fork shape, the fork can be rotated such that when one tine moves up as the wrist of the fork is rotated the other moves down. The rotations of the fork can be limited to small angles. For example, these angles can be equivalent to the localized substrate warp angle. The localized substrate warp angle is the angle created by the warping on the substrate at a specified location.

[0054] Another method of the present invention involves moving the end effector under the substrate and then moving the end effector vertically to engage and support the substrate. In this embodiment, once the end effector approaches the substrate, the vacuum system can systematically turn on one the primary vacuum orifices in an attempt to capture the substrate. If the substrate is not captured by the first orifice that is turned on, the vacuum to the first orifice is turned off and, where there is more than one primary orifice, the vacuum to a second primary orifice is turned on. Therefore, only one orifice will be turned on at a single time and will be sensing whether or not the substrate has been captured. (If there is only one primary orifice, the end effector may be moved and rotated until that orifice makes contact with the substrate). If the substrate has not been captured, then the second orifice can be turned off and the next orifice can be turned on. The process continues through all the available primary orifices and back through the rotation of primary orifices until the substrate is captured.

[0055] When the substrate is finally captured by at least one of the primary orifices, it will be distorted into the plane of the end effector in the proximity of the capturing orifice. Once one orifice makes contact with the substrate, the other orifices can be used to gain additional control over the substrate. [0056] In the fork end effector embodiment, if one end of the fork, either the left portion or the right portion, makes vacuum contact with the substrate, the other portion of the fork may be rotated onto the substrate after the robotic arm wrist is rotated about the substrate plane. This is particularly helpful where the substrate is highly bowed.

[0057] In another embodiment, the end effector has a rotator in an axis perpendicular to the wrist rotational axis. This rotator may allow for pitching the end effector relative to the substrate plane perpendicular to the rolling center axis of the substrate, thus enabling the substrate to be captured by the end effector.

[0058] FIGS. 5A-5C illustrate another method of grasping highly shaped substrates. FIG. 5 A depicts a front view of an end effector 50, attempting to grasp a high shaped substrate 52. The end effector 50 is a fork end effector having a first primary orifice 54 on a first tine of the fork, a second primary orifice 56, on the second tine of the fork, and one secondary orifice 58. FIG. 5 A depicts the end effector approaching the substrate from below. Then, as shown in FIG 5B, the robot wrist of the end effector has rotated the end effector and the first primary orifice 54 is close enough to the wafer to make vacuum contact with the wafer. The vacuum forces in the first primary orifice 54 pull the substrate down toward the end effector, enabling the secondary orifice 58 to make contact with the substrate. Once two orifices have created vacuum seals with the substrate, the substrate begins to straighten (FIG. 5C). Then, the wrist axis rotates to the horizontal position and the second primary orifice 56 is able to make contact with the substrate. Once the second primary orifice makes contact with the substrate, the end effector has captured the substrate and the substrate can be transported.

[0059] In another embodiment, the end effector may engage the substrate in a vibratory manner. A motor attached to the end effector may vibrate the fork at a frequency from about 1.0 Hz to 500 Hz, preferably at about the resonance frequency of the substrate. The resonance frequency of a given substrate will vary to some degree and will be dominated by the substrate's thickness. The resonance frequency of the substrate is determined by frequency sweeping the vacuum control signal and measuring the displacement on the substrate. Generally, when an object is vibrated at its resonance frequency, the object will show the greatest response. When the on- off rate of the vacuum is frequency swept and the frequency passes through the substrate's resonance frequency, the positional data will show maximum displacement at this resonant on-off rate.

[0060] Additionally, the amplitude of the vibrations may be modulated. This should done with care, so as to not create particulates while the substrate and end effector are vibrated. The vibration of the end effector can be induced in R (distance), θ (angle), or Z (elevation); the roll and pitch axes; or any combination thereof. The transmission of vibrations from the end effector to the substrate can cause the substrate to vibrate. Consequently, the vibration of the substrate can change the substrate's shape slightly. The combination of the oscillatory behavior of the fork and the vibration of the substrate may permit contact between the fork and the substrate such that the vacuum end effector may engage the substrate. Once the end effector engages the substrate, the robotic arm can move and manipulate the substrate.

[0061] In another embodiment, the method of capturing a highly shaped substrate can be accomplished through the following steps, as depicted in FIG. 6:

[0062] Radially extend the end effector under the substrate center (100).

[0063] Move the end effector in the Z direction while sensing for vacuum (102).

[0064] Rotate the wrist of the fork in the roll direction at a small angle and move the end effector up in Z while sensing for vacuum (104). If capture is not achieved, the small angle of the fork can be changed, such that the total range of angle adjustment would be +/- 2 degrees.

[0065] Rotate the wrist of the fork in the pitch direction at a small angle and move up in the Z-direction while sensing for vacuum (106). If capture is not achieved, the small angle of the fork can be changed, such that the total range of angle adjustment would be +/- 2 degrees.

[0066] Vibrate the end effector in the pitch and/or roll directions and move the end effector up in the Z direction until the substrate is supported (108).

[0067] Frequency modulate the vacuum force on the one or more primary orifice(s) to capture the substrate (1 10).

[0068] Another aspect of the present invention relates to a vacuum or fluidic conduit system integrated into a robotic arm. The system may allow for an air flow of greater than about 1 ft³/min and may be external or internal to the robotic arm. FIG. 7 depicts the vacuum conduit system 60, the robot arm 10, and the end effector 12. The conduit system may be a flexible conduit system, allowing for the unrestricted movement of the robot arm without adding stiffness or damping. The conduit system can change the inherent stiffness and damping properties of the robotic arm by as much as three percent in some instances. This design can be what is referred to as an umbilical cord design. A flexible, hollow tube 62 is connected to both the robotic arm 10 and the end effector 12. The hollow tube permits the transmission of vacuum pressure to the end effector. The hollow tube may be composed, for example, of polyurethane and may contain precision bent stainless tubes, and may have a diameter from about 3 mm to about 10 mm.

[0069] Another aspect of the present invention relates to the independent analog and digital control of the end effector while sensing through the various orifices on the end effector. The analog and digital control may allow for modulated vacuum force generation between the end effector and the substrate at a frequency close or identical to the resonant frequency of the substrate. Thus, a large portion of the energy of the injected analog signal may be at a frequency that is consistent with the resonance frequency of the substrate. This may provide attraction forces at a frequency where the combination of end effector and substrate offer minimum mechanical impedance. Displacement measurements of the substrate during the capture process may be made through back pressure sensing and capacitance measurements. The injection of the analog signal creates vacuum forces on the substrates and the vacuum forces are aligned with the substrate's dynamic characteristics. This enables the positive capture of the substrate by the end effector. [0070] In one embodiment, one or more vacuum valves may be used to proportionally adjust the vacuum flow for modulation of the vacuum flow through the end effector orifices. Solenoid vacuum valves may be used that are driven in a pulse-width-modulated (PWM) mode for the purpose of achieving quasi- proportional vacuum flow characteristics. Vacuum flow control can be accomplished using a proportional pneumatic valve or by controlling solenoid vacuum valves in a PWM mode. The switching and sensing of all devices can be conducted by the robot's digital signal processor.

[0071] In one embodiment, the analog detection of the substrate can be accomplished by measuring the back-pressure from an orifice, using, for example, a diaphragm type pressure sensor/detector. The amount of back at pressure at an orifice can be a direct indication of how close the substrate was to sealing an orifice, i.e., how close the end effector was to grasping the substrate.

[0072] Alternately, the actual position of the substrate in relation to the substrate can be detected using one or more embedded capacitance sensors. The capacitance sensors can be located on the end effector around or near the vacuum orifices. FIG. 8A depicts a fork end effector 80, a first primary orifice 81 , a second primary orifice 82, and a third primary orifice 83. Each primary orifice has a co-located capacitive ring around each primary orifice. For example, the first primary orifice 81 has a first capacitive ring 84, the second primary orifice 82 has a second capacitive ring 85, and the third primary orifice 83 has a third capacitive ring 86. FIG. 8B depicts another embodiment including a fork end effector 87 having a first primary orifice 88, a second primary orifice 89, and a third primary orifice 90. Each primary orifice has a capacitive sensor offset from the primary orifice. For example, the first primary orifice 88 has a first capacitive sensor 91, the second primary orifice 89 has a second capacitive sensor 92, and the third primary orifice 90 has a third capacitive sensor 93.

[0073] Coupling the ability to modulate the pressure flow through an orifice at frequency with the ability to measure the substrate position, optimizes the ability to capture the substrate. The steps for accomplishing this include the following, as depicted in FIG. 9:

[0074] Determine the position of the substrate with respect to a given orifice (200).

[0075] Turn on the vacuum to that single orifice (202).

[0076] Determine the position of the substrate with respect to the orifice (204).

[0077] Turn the vacuum to the orifice on and then off at a known sweep rate from about 1.0 to about 60 Hz while collecting a continuous stream of orifice to substrate position information (206).

[0078] From the positional information determine the best vacuum on-off rate (208).

[0079] Implementing this rate for each of the primary orifices until the substrate is captured for safe transport (210).

[0080] This new vacuum handling technology optimizes the vacuum force in a manner that provides maximize effectiveness to capture and then flex the substrate into the plane of the end effector. With the substrate in-plane with the end effector, additional vacuum orifices can now apply holding forces for positive control of the substrates.

[0081] While there have been described what are presently believed to be the preferred embodiments of the invention, those skilled in the art will realize that changes and modifications may be made thereto without departing from the spirit of the invention, and it is intended to include all such changes and modifications as fall within the true scope of the invention.

[0082] What is claimed is:

Claims

I . A device for handling a highly shaped substrate comprising: an end effector having a first side and a second side, the first side including a planar surface and having a first primary vacuum orifice in the planar surface for applying a vacuum force; and a sensor disposed on the end effector for sensing a level of contact between the substrate and the end effector, wherein the vacuum force through the first primary orifice is regulated by the sensing of the sensor. 2. The device of claim 1, further comprising: a first secondary vacuum orifice in the planar surface.

3. The device of claim 2, further comprising: a second secondary vacuum orifice in the planar surface.

4. The device of claim 2, wherein the second side of the end effector includes a planar surface and has a second secondary vacuum orifice located in the planar surface of the second side.

5. The device of claim 1, wherein the end effector comprises a fork.

6. The device of claim 1, wherein the end effector comprises a paddle.

7. The device of claim 1, wherein the end effector comprises a ring. 8. The device of claim 1, wherein the end effector includes a second primary vacuum orifice.

9. The device of claim 1, wherein the second side of the end effector includes a planar surface and has a second primary vacuum orifice located in the planar surface of the second side. 10. The device of claim 1, wherein the sensor is an embedded capacitance sensor.

I 1. The device of claim 1, wherein the sensor senses the back pressure in the first primary vacuum orifice.

12. The device of claim 1 further comprising: a robot arm connected to the end effector; and a vacuum conduit system in fluid communication with the end effector.

13. The device of claim 12, wherein the vacuum conduit system is external to the end effector.

14. The device of claim 12, wherein the vacuum conduit system is internal to the end effector.

15. The device of claim 12, wherein the vacuum conduit system has an umbilical cord configuration. 16. The device of claim 12, wherein the vacuum conduit system is flexible.

17. A device for handling a highly shaped substrate comprising: an end effector having a first side and a second side, the first side including a planar surface and having a first primary vacuum orifice in the planar surface for applying a vacuum force; and a back pressure sensor disposed on the end effector for sensing a level of contact between the substrate and the end effector.

18. The device of claim 17, wherein the back pressure sensor is a diaphragm pressure sensor.

19. A device for handling a highly shaped substrate comprising: an end effector having plurality of vacuum orifices, each of the vacuum orifices applying a vacuum force; and a plurality of vacuum valves, each of the vacuum valves modulating the vacuum force through one of the plurality of vacuum orifices.

20. The device of claim 19, wherein the vacuum valve is a solenoid valve. 21. The device of claim 19, wherein the vacuum valve is a proportional pneumatic valve.

22. A device for handling a highly shaped substrate comprising: an end effector having a first side and a second side, the first side including a planar surface and having a first primary vacuum orifice in the planar surface for applying a vacuum force to a substrate; and a sensor disposed on the end effector for sensing a level of contact between the substrate and the end effector, wherein the vacuum force of the first primary orifice is greater than about 1 fVVmin.

23. A method of handling a highly shaped substrate comprising: positioning an end effector in proximity to a highly shaped substrate; applying a vacuum force through a first vacuum orifice in the end effector; and capturing the substrate with the vacuum force.

24. The method of claim 23, further comprising rotating the end effector to capture the substrate.

25. The method of claim 23 further comprising vibrating the end effector to capture the substrate.

26. The method of claim 23, wherein the vibrating of the end effector is performed at the resonance frequency of the substrate. 27. The method of claim 23, wherein the vacuum force is applied at the resonance frequency of the substrate.

28. The method of claim 23, wherein the vacuum force is modulated through an analog signal

29. The method of claim 23, wherein the vacuum force is modulated at the resonant frequency of the substrate.

30. The method of claim 23, further comprising detecting contact between the substrate and the end effector by analog sensing of back pressure in the vacuum orifice.

31. The method of claim 30, wherein the contact is detected by an embedded capacitance sensor.

32. The method of claim 23, further comprising detecting the position of the substrate relative to the vacuum orifice through analog sensing of back pressure.

33. The method of claim 32, wherein the position is detected through an embedded capacitance sensor.

34. The method of claim 23, further comprising: turning off the vacuum force in the first vacuum orifice; and applying another vacuum force to a second vacuum orifice in the end effector.

35. A method for handling a highly shaped substrate comprising: positioning near a substrate an end effector having a plane and a plurality of vacuum orifices, each vacuum orifice having a vacuum force; , deforming the substrate with the vacuum force from a first vacuum orifice of the plurality of vacuum orifices into the plane of the end effector; and capturing the substrate with the vacuum force of a second vacuum orifice of the plurality of vacuum orifices.

36. A method for handling a highly shaped substrate comprising: positioning an end effector having a vacuum orifice near a substrate; modulating a vacuum force through the vacuum orifice at about the resonant frequency of the substrate; sensing the displacement of the substrate for modulating of the vacuum force; and capturing the substrate based on the sensing of the displacement of the substrate.

37. The method of claim 36, wherein sensing the displacement of the substrate comprises sensing back pressure in the vacuum orifice.

38. The method of claim 36, wherein sensing the displacement of the substrate comprises measuring capacitance.

39. A method of determining the resonant frequency of a substrate comprising: applying a vacuum force to the substrate; modulating the vacuum force over a range of frequencies; sensing a displacement of the substrate; and determining the resonant frequency of the substrate to be the frequency at which the greatest displacement of the substrate occurs.