Patent Application
20060060631
The present invention relates to the field of precision motion control devices generally and, more particularly, to motion control devices which are particularly well-suited for use with a wire bonder machine to provide high speed linear and rotational movement of a bonding head.
Wire bonders (aka wire bonder machines, wire bonding machines, etc.) are known in the prior art. Wire bonders are used in semiconductor manufacturing to attach semiconductor dies directly to a circuit board substrate. Automatic wire bonders have been developed which utilize stored position data to control the bonding operation. Certain wire bonders, such as the Maxμm™ IC Ball Bonder sold by Kulicke and Soffa Industries, Inc., Willow Grove, Pa., use a vertically displaceable wire bonding head along with a horizontally translatable semiconductor work table. In this conventional wire bonder, three high speed motors (one associated with movement in each of the three spatial dimensions) are used to position the semiconductor device and bonding tool at the appropriate locations.
Another example of a wire bonder is disclosed in U.S. Pat. No. 6,460,751 (Thurlemann). Thurlemann discloses a bondhead drive mechanism including two linear motors, 12 and 14. First linear motor 12 drives the bondhead for providing translational, linear motion, while second linear motor 14 drives rotary beam 4 portion of the bondhead for rotary movement. Thus, movement of a bonding tool or capillary 7 is controlled for both translation and rotation by linear motors 12 and 14. Thurlemann discloses two linear motors 12, 14 having movable coils 11 and 15, respectively, which move along axes of motion which are perpendicular to one another.
One way to reduce the costs associated with the manufacture of a semiconductor product is to increase the speed of operation of the bonding machine thereby increasing the number of units produced per hour. Speed of operation is typically limited by a combination of the weight and weight distribution of moving components and the corresponding amount of force used to rapidly accelerate and decelerate the moving components.
Thus, it would be desirable to provide an improved motion control device with a well-balanced, compact design which is suitable for use in a wire bonder machine and which provides high speed bonding.
According to an exemplary embodiment of the present invention, a motion control device for controlling rotary and linear motion is provided. The motion control device includes a first linear actuator having a first fixed member and a first moveable drive member, the first moveable drive member being driven for motion relative to the first fixed member along a first longitudinal axis. The motion control device also includes a second linear actuator having a second fixed member and a second moveable drive member, the second movable drive member being driven for motion relative to the second fixed member along a second longitudinal axis. The motion control device also includes a drive assembly, the drive assembly being configured to be driven by the first moveable drive member and the second moveable drive member for (a) linear motion along a first axis substantially parallel to the first longitudinal axis and the second longitudinal axis, and (b) rotation about an axis of rotation. A position of each of the first moveable drive member and the second moveable drive member is separately controllable to control rotational and linear positions of the drive assembly.
According to another exemplary embodiment of the present invention, a wire bonding machine is provided. The wire bonding machine includes a work table for supporting at least one semiconductor device to be wire bonded, a conveyance system for translating the work table in a substantially horizontal direction, a wire bonding head assembly including a bonding tool, and a motion control device for controlling rotary and linear motion. The motion control device includes a first linear actuator having a first fixed member and a first moveable drive member, the first moveable drive member being driven for motion relative to the first fixed member along a first longitudinal axis. The motion control device also includes a second linear actuator having a second fixed member and a second moveable drive member, the second movable drive member being driven for motion relative to the second fixed member along a second longitudinal axis. The motion control device also includes a drive assembly, the drive assembly being configured to be driven by the first moveable drive member and the second moveable drive member for (a) linear motion along a first axis substantially parallel to the first longitudinal axis and the second longitudinal axis, and (b) rotation about an axis of rotation. A position of each of the first moveable drive member and the second moveable drive member is separately controllable to control rotational and linear positions of the drive assembly.
The foregoing and other features of presently preferred embodiments of the invention and advantages of the presently preferred embodiments will become more apparent in light of the following detailed description, as illustrated in the accompanying figures. As will be realized, the invention is capable of modifications in various respects, all without departing from the invention. Accordingly, the drawings and the description are to be regarded as illustrative in nature, and not as restrictive.
For the purpose of illustrating the invention, the drawings show presently preferred embodiments of the invention. However, it should be understood that this invention is not limited to the precise arrangements and instrumentalities shown in the drawings.
The present invention relates to motion control devices for controlling rotary and linear motion. According to certain exemplary embodiments of the present invention, a motion control device includes first and second linear actuators coupled to a drive assembly. The linear actuators are arranged to extend along substantially parallel longitudinal axes and are separately controllable to control linear and rotational motion of the drive assembly. For example, the linear actuators may be voice coil motors or linear servomotors. Other exemplary types of motors include multiphase, ironcore, ironless or magnetic rod linear motors. The motion control device may be incorporated into a wire bonding machine.
Referring now to the drawings, wherein like reference numerals illustrate corresponding or similar elements throughout the several views,
To facilitate the description of the presently preferred embodiments, it will be useful to define a coordinate system as a point of reference for certain spatial relationships and/or displacements. As indicated in the various figures, an X-Y plane corresponds to a “horizontal” plane while X-Z and Y-Z planes correspond to “vertical” planes. The X axis corresponds to a direction of travel of workpiece 30. The Y axis corresponds to a direction of translation of drive assembly 140. The Z axis corresponds to the “vertical” direction. Rotational motion of drive assembly 140 in the X-Y plane occurs through an angular displacement ø.
Wire bonder head assembly 10 is positioned above indexing conveyance system 40, which, as in the illustrated embodiment, may include conventional set of guide rails 42 and a motor drive (not shown) for translating workpiece 30 (e.g., a semiconductor device) relative to bonding tool 12. Any conventional wire bonding conveyance system may be used in the present invention. More particularly, workpiece 30 is mounted on work table 20 which holds one or more workpieces 30. Work table 20 (or magazine) may be supplied to indexing conveyance system 40 by magazine handler 50.
Wire bonder head assembly 10 may be mounted to the bonding machine through a conventional attachment which permits bonding tool 12 to move vertically (i.e., in the Z direction) relative to workpiece 30. U.S. Pat. No. 4,266,710, the disclosure of which is incorporated herein by reference in its entirety, describes one type of mounting arrangement that could be used in the present invention. The mounting arrangement may include a pivot or hinge mount which permits bonding tool 12 to move up and down in the Z direction (toward and away from workpiece 30) so as to permit the bonding of the wires to the semiconductor device at various vertical positions. Those skilled in the art are familiar with such mounting arrangements as well as other mechanisms for vertical positioning of a bonding tool and, therefore, no further discussion is needed. The present invention can be readily incorporated into many conventional wire bonders, such as Kulicke and Soffa's 8028 Ball Bonder or Maxμm™ IC Ball Bonder.
With reference now to
Each moving coil 132 is coupled to drive head portion 142 of drive assembly 140. Drive assembly 140 includes drive head 142, which is rotatably coupled with platform 146. Drive head 142 rotates about axis of rotation 144. Wire bonder head assembly 10 is preferably disposed beneath platform 146, opposite drive head 142. Drive head 142 is coupled to wire bonder head assembly 10 such that wire bonder head assembly 10 rotates with drive head 142. Platform 146 translates with drive head 142 and wire bonder head assembly 10 along first axis 148 on rails 136 formed in yokes 122. First axis 148 may be, for example, substantially parallel to the longitudinal axes of motion 134. Further, first axis 148 may be, for example, substantially perpendicular to axis of rotation 144.
The travel of moving coils 132 is chosen to allow a range of linear motion of bonding tool 12 at least across the entire width W of workpiece 30. Moving coils 132 are sized relative to central portion 126 of yoke 122 to allow moving coils 132 to be rotated, for example, approximately plus or minus 30 degrees about axis of rotation 144 over the entire range of linear translation of bonding tool 12 along the Y axis. Of course, different ranges of linear motion and rotative motion (e.g., larger ranges of motion, smaller ranges of motion) are contemplated.
In operation, drive head 142 is driven by moving coils 132 for translation along first axis 148 and for rotation about axis of rotation 144. For example, by controlling both of moving coils 132 to move in the same amount and in the same direction along the longitudinal axes of motion 134, drive head 142, platform 146, and wire bonder head assembly 10 are all translated in the Y direction along first axis 148. If, however, the moving coils 132 are moved in different directions or in the same direction by different amounts along the longitudinal axes of motion 134, drive head 142, and wire bonder head assembly 10 are rotated relative to platform 146.
With particular reference now to
Drive head 142′ functions in a manner similar to drive head 142 illustrated and described with reference to
The travel of drive links 168 is chosen to allow a range of linear motion of bonding tool 12 at least across the entire width W of workpiece 30 and to further allow a range of rotational motion of approximately, for example, plus or minus 30 degrees throughout the range of linear motion. Of course, different ranges of linear motion and rotative motion (e.g., larger ranges of motion, smaller ranges of motion) are contemplated.
In operation, the movement of each drive link 168 is capable of being separately controllable. Drive head 142′ is driven by drive links 168 for translation along first axis 148 and for rotation about axis of rotation 144. For example, by controlling both drive links 168 to move in the same amount and in the same direction along the longitudinal axes of motion 170, drive head 142′, platform 146, and wire bonder head assembly 10 are all translated in the Y direction along first axis 148. If, however, drive links 168 are moved in different directions or in the same direction by different amounts along longitudinal axes of motion 170, drive head 142′, and wire bonder head assembly 10 are rotated relative to the platform 146.
With particular reference now to
Drive head 142″ functions in a manner similar to drive heads 142 and 142′ described above with respect to
The travel of gear racks 182 is chosen to allow a range of linear motion of bonding tool 12 at least across the entire width W of the workpiece 30 and to further allow a range of rotational motion of approximately plus or minus 30 degrees throughout the range of linear motion. Of course, different ranges of linear motion and rotative motion (e.g., larger ranges of motion, smaller ranges of motion) are contemplated.
With particular reference now to
Those skilled in the art will recognize that the linear motion in the Y direction and rotational motion in the ø direction of wire bonder head assembly 10 afforded by the exemplary linear actuator assemblies 110, 110′ and 110″ may be combined with other ranges of motion, for example, a linear motion in the X direction provided by conveyance system 40 and a motion predominately in the Z direction of bonding tool 12 to provide a desired range of motion of bonding tool 12 to successfully complete processing of workpiece 30.
It should be further recognized that angular movement of bonding tool 12 about Z axis of rotation 144 provides, in addition to positional change in the X direction, some positional change in the Y-direction as well. Thus, the programming which controls the movement of moving coils 132 or drive links 168 or gear racks 182 to properly position bonding tool 12 for bonding, may take into account both the translational and rotational motion of bonding tool 12.
A camera (not illustrated in any of the illustrated exemplary embodiments) for obtaining image data related to workpiece 30 could be provided. The camera could be used to obtain position data, such as X-Y location and orientation, of workpiece 30 and/or bonding locations on workpiece 30. The data from the camera may be fed to a microprocessor or similar controller for use in controlling wire bonder head assembly 10 and bonding tool 12. For example, a fixed line scan camera may be used. Such cameras and positioning systems are well known in the art and, therefore, no further discussion is needed.
As a further option, the wire bonder machine could be provided with multiple work tables, for example, two work tables 20 running in parallel lanes (not illustrated) on
separate sets of guide rails 42. Such a “double lane” arrangement would permit the course movement of workpiece 30 in, for example, lane 1, to be moved into bonding position while the bonding head is attaching wires on workpiece 30 in lane 2. Such an arrangement may speed up the manufacturing process by moving the parts in and out of the bondable area in parallel without stopping the process of attaching wires.
It will be appreciated that other types of devices such as multiphase ironcore, ironless or magnetic rod linear motors could be incorporated into a motion control device (e.g., motion control device 100), in addition to the illustrated linear voice coil actuator 130 and linear servomotor 160 disclosed herein.
From this disclosure, the artisan will recognize that the presently preferred embodiments are conducive to a very compact, relatively light-weight, and well-balanced design. It is expected that motion control device 100 and the exemplary linear actuator assemblies 110, 110′, and 110″ will be especially useful when incorporated into wire bonding machines as the assemblies 110, 110′, and 110″ are expected to permit higher operating speeds of such machines.
The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.
This application is related to and claims priority from U.S. Provisional Application Ser. No. 60/611954, filed Sep. 22, 2004, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60611954 | Sep 2004 | US |
