Abstract:
A modified ultrasonic bonding machine and process uses a sharpened bonding wedge to perform cutting of short material. The sharpened wedge is controlled by the same position control device control used to position the bonding wedge for bonding. The software is modified to permit selection of bonding or cutting, and the bonding wedge is replaced with a cutting wedge. The modified ultrasonic bonding machine allows the operator to use the automated system of the machine to do the cutting, and the precision gained ensures that no damage to the parts is caused by the cutting process.

Description:
BACKGROUND 
       [0001]    1. Field: 
         [0002]    The disclosure relates generally to vibratory bonding and more specifically to computer control of a bonding machine to perform its normal bonding function, and also to perform rework by allowing an operator to use the remotely controlled three axis motion of the bonding machine to position a sharpened wedge over a bridge between bonds and to cut the bridge. 
         [0003]    2. Description of the Related Art: 
         [0004]    Ultrasonic Bonding is a known process for fusing electrical connections through the application of pressure and ultrasonic energy. Ultrasonic Bonding is performed by machines that are both computer-controlled and operator controlled. The Ultrasonic bonding machine has electrical motors for movement in the x axis, the y axis and in the z axis. Software allows a part to be indexed for precise movement in response to a joystick controlled by an operator. The operator moves an ultrasonic wedge into position while viewing the circuit through a microscope. The joystick enables the user to precisely place a bonding wedge onto the wire to be bonded. A weight attached to a wedge holder applies downward pressure to the wedge ensuring contact between the wedge and the wire to be bonded. When the operator is ready to initiate the bonding process, the operator presses a button on the joystick in order to send ultrasonic energy through the bonding wedge and onto the wire. The ultrasonic energy creates the bond. 
         [0005]    When bonds are made in close proximity to other bonds, material from one bond may contact a neighboring bond. Such contact is referred to as bridging, and the bridge between the two bonds causes a short and results in a failure of the part at a continuity test. Shorts caused by bridging must be repaired, and the repair process is referred to as reworking the bond. The current method to rework the bond is for the operator to manually cut the bridge of material connecting two bonds using a sharp blade. The operator cannot precisely control the movement of the blade and the precision is only as good as the motor reflexes of the operator. Moreover, because the circuits to which the bonds are being applied are very small, the operator views the bridge and the bonds joined by the bridge under a microscope. Since the dimensions are so small, accurate manual movement of the cutting instrument is very difficult. Damage to components of the part can easily arise due to imprecision arising from the operators vision and motor reflexes. Furthermore, the manual operation of physically cutting the bridge between two bonds is difficult and time consuming. 
         [0006]    What is needed beyond the prior art is a way to automate the rework process to eliminate manual manipulation of a cutting tool by the operator. 
       SUMMARY 
       [0007]    According to one embodiment, a modified ultrasonic bonding machine comprises a physical component and a software component. Together, the physical component and the software component modify an existing ultrasonic bonding machine so that the precision of the bonding process is adapted to the rework process, thereby eliminating a manual cutting of a bridge between bonds. The software component adapts computer control of the bonding machine to allow operator selection of bonding or cutting. In response to a selection of bonding or rework, an operation of a control on a position control device is changed from causing an ultrasonic bond to causing a cutting action. The physical component is a sharpened wedge that is inserted into a wedge arm of the cutting machine. In one embodiment, the sharpened wedge is manually placed after manual removal of the bonding wedge by the operator. In another embodiment, the bonding machine is adapted to have a rotatable wedge arm so that the computer can automatically rotate the selected wedge into position. In another embodiment, software creates a new function and flag in the source code of the ultrasonic bonder to give it the rework capability. The sharpened wedge cuts the bridge causing an electrical short in response to activation of the control by the operator. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0008]      FIG. 1  is an exemplary server-client computer system; 
           [0009]      FIG. 2  is an exemplary computer framework; 
           [0010]      FIG. 3  is an exemplary software architecture for a server-client system containing application software; 
           [0011]      FIG. 4  is a memory containing elements of the application software; 
           [0012]      FIG. 5A  is a front perspective view of an ultrasonic bonding machine; 
           [0013]      FIG. 5B  is a front perspective close up of the wedge holder and weight of the ultrasonic bonding machine positioned above a part held in a transfer tool; 
           [0014]      FIG. 5C  is a side view of the bonding machine wedge holder and wedge; 
           [0015]      FIG. 5D  is a part situated in a transfer tool; 
           [0016]      FIG. 6A  is a plurality of wire bonds with shorting; 
           [0017]      FIG. 6B  is a plurality of reworked bonds with shorting material cut away; 
           [0018]      FIG. 7A  is a prior art wedge used by the ultrasonic bonding machine; 
           [0019]      FIG. 7B  is an ultrasonic wedge sharpened for use as a cutter in an automated rework system; 
           [0020]      FIG. 8  is a flowchart of the bonding machine control software modified to perform both bonding and automated rework; and 
           [0021]      FIG. 9  is a flowchart of the operator process using the modified bonding machine to both bond and automated rework. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    As will be appreciated by one skilled in the art, the present invention may be embodied as a system, method or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, the present invention may take the form of a computer program product embodied in any tangible medium of expression having computer usable program code embodied in the medium. 
         [0023]    Any combination of one or more computer usable or computer readable medium(s) may be utilized. The computer-usable or computer-readable medium may be, for example but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CDROM), an optical storage device, a transmission media such as those supporting the Internet or an intranet, or a magnetic storage device. Note that the computer-usable or computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory. In the context of this document, a computer-usable or computer-readable medium may be any medium that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The computer-usable medium may include a propagated data signal with the computer-usable program code embodied therewith, either in baseband or as part of a carrier wave. The computer usable program code may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc. 
         [0024]    Computer program code for carrying out operations of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). 
         [0025]    The present invention is described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. 
         [0026]    These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer program instructions may also be stored in a computer-readable medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks. 
         [0027]    The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
         [0028]    With reference now to the figures, and in particular with reference to  FIGS. 1-2 , exemplary diagrams of data processing environments are provided in which illustrative embodiments may be implemented. It should be appreciated that  FIGS. 1-2  are only exemplary and are not intended to assert or imply any limitation with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environments may be made. 
         [0029]      FIG. 1  is a pictorial representation of a network of a data processing system in which illustrative embodiments may be implemented. Network data processing system  100  is a network of computers in which the illustrative embodiments may be implemented. Network data processing system  100  contains network  102 , which is the medium used to provide communication links between various devices and computers connected together within network data processing system  100 . Network  102  may include connections, such as wire, wireless communication links, or fiber optic cables. 
         [0030]    In the depicted example, server  104  and server  106  connect to network  102  along with storage unit  108 . In addition, clients  110 ,  112 , and  114  connect to network  102 . Clients  110 ,  112 , and  114  may be, for example, personal computers or network computers. In the depicted example, server  104  provides data, such as boot files, operating system images, and applications to clients  110 ,  112 , and  114 . Clients  110 ,  112 , and  114  are clients to server  104  in this example. Network data processing system  100  may include additional servers, clients, and other devices not shown. 
         [0031]    Program code located in network data processing system  100  may be stored on a computer recordable storage medium and downloaded to a data processing system or other device for use. For example, program code may be stored on a computer readable storage medium on server  104  and downloaded to client  110  over network  102  for use on client  110 . 
         [0032]    In the depicted example, network data processing system  100  is the Internet with network  102  representing a worldwide collection of networks and gateways that use the Transmission Control Protocol/Internet Protocol (TCP/IP) suite of protocols to communicate with one another. At the heart of the Internet is a backbone of high-speed data communication lines between major nodes or host computers, consisting of thousands of commercial, governmental, educational and other computer systems that route data and messages. Of course, network data processing system  100  also may be implemented as a number of different types of networks, such as for example, an intranet, a local area network (LAN), or a wide area network (WAN).  FIG. 1  is intended as an example, and not as an architectural limitation for the different illustrative embodiments. 
         [0033]    With reference now to  FIG. 2 , a block diagram of a data processing system is shown in which illustrative embodiments may be implemented. Data processing system  200  is an example of a computer, such as server  104  or client  110  in  FIG. 1 , in which computer-usable program code or instructions implementing the processes may be located for the illustrative embodiments. In this illustrative example, data processing system  200  includes communications fabric  202 , which provides communications between processor unit  204 , memory  206 , persistent storage  208 , communications unit  210 , input/output (I/O) unit  212 , and display  214 . 
         [0034]    Processor unit  204  serves to execute instructions for software that may be loaded into memory  206 . Processor unit  204  may be a set of one or more processors or may be a multi-processor core, depending on the particular implementation. Further, processor unit  204  may be implemented using one or more heterogeneous processor systems in which a main processor is present with secondary processors on a single chip. As another illustrative example, processor unit  204  may be a symmetric multi-processor system containing multiple processors of the same type. 
         [0035]    Memory  206  and persistent storage  208  are examples of storage devices. A storage device is any piece of hardware that is capable of storing information either on a temporary basis and/or a permanent basis. Memory  206 , in these examples, may be, for example, a random access memory or any other suitable volatile or non-volatile storage device. Persistent storage  208  may take various forms depending on the particular implementation. For example, persistent storage  208  may contain one or more components or devices. For example, persistent storage  208  may be a hard drive, a flash memory, a rewritable optical disk, a rewritable magnetic tape, or some combination of the above. The media used by persistent storage  208  also may be removable. For example, a removable hard drive may be used for persistent storage  208 . 
         [0036]    Communications unit  210 , in these examples, provides for communications with other data processing systems or devices. In these examples, communications unit  210  is a network interface card. Communications unit  210  may provide communications through the use of either or both physical and wireless communications links. 
         [0037]    Input/output unit  212  allows for input and output of data with other devices that may be connected to data processing system  200 . For example, input/output unit  212  may provide a connection for user input through a keyboard and mouse. Further, input/output unit  212  may send output to a printer. Display  214  provides a mechanism to display information to a user. 
         [0038]    Instructions for the operating system and applications or programs are located on persistent storage  208 . These instructions may be loaded into memory  206  for execution by processor unit  204 . The processes of the different embodiments may be performed by processor unit  204  using computer implemented instructions, which may be located in a memory, such as memory  206 . These instructions are referred to as program code, computer-usable program code, or computer-readable program code that may be read and executed by a processor in processor unit  204 . The program code in the different embodiments may be embodied on different physical or tangible computer-readable media, such as memory  206  or persistent storage  208 . 
         [0039]    Program code  216  is located in a functional form on computer readable media  218  that is selectively removable and may be loaded onto or transferred to data processing system  200  for execution by processor unit  204 . Program code  216  and computer-readable media  218  form computer program product  220  in these examples. In one example, computer-readable media  218  may be in a tangible form, such as, for example, an optical or magnetic disc that is inserted or placed into a drive or other device that is part of persistent storage  208  for transfer onto a storage device, such as a hard drive that is part of persistent storage  208 . In a tangible form, computer-readable media  218  also may take the form of a persistent storage, such as a hard drive, a thumb drive, or a flash memory that is connected to data processing system  200 . The tangible form of computer-readable media  218  is also referred to as computer-recordable storage media. In some instances, computer-recordable media  218  may not be removable. 
         [0040]    Alternatively, program code  216  may be transferred to data processing system  200  from computer-readable media  218  through a communications link to communications unit  210  and/or through a connection to input/output unit  212 . The communications link and/or the connection may be physical or wireless in the illustrative examples. The computer-readable media also may take the form of non-tangible media, such as communications links or wireless transmissions containing the program code. 
         [0041]    In some illustrative embodiments, program code  216  may be downloaded over a network to persistent storage  208  from another device or data processing system for use within data processing system  200 . For instance, program code stored in a computer readable storage medium in a server data processing system may be downloaded over a network from the server to data processing system  200 . The data processing system providing program code  216  may be a server computer, a client computer, or some other device capable of storing and transmitting program code  216 . 
         [0042]    The different components illustrated for data processing system  200  are not meant to provide architectural limitations to the manner in which different embodiments may be implemented. The different illustrative embodiments may be implemented in a data processing system including components in addition to, or in place of, those illustrated for data processing system  200 . Other components shown in  FIG. 2  can be varied from the illustrative examples shown. 
         [0043]    The different embodiments may be implemented using any hardware device or system capable of executing program code. As one example, the data processing system may include inorganic components integrated with organic components and/or may be comprised entirely of organic components excluding a human being. For example, a storage device may be comprised of an organic semiconductor. As another example, a storage device in data processing system  200  is any hardware apparatus that may store data. Memory  206 , persistent storage  208 , and computer-readable media  218  are examples of storage devices in a tangible form. 
         [0044]    In another example, a bus system may be used to implement communications fabric  202  and may be comprised of one or more buses, such as a system bus or an input/output bus. Of course, the bus system may be implemented using any suitable type of architecture that provides for a transfer of data between different components or devices attached to the bus system. Additionally, a communications unit may include one or more devices used to transmit and receive data, such as a modem or a network adapter. Further, a memory may be, for example, memory  206  or a cache, such as found in an interface and memory controller hub that may be present in communications fabric  202 . 
         [0045]    Turning to  FIG. 3 , typical software architecture  300  for a server-client system is depicted in accordance with an illustrative embodiment. At the lowest level, operating system  302  is utilized to provide high-level functionality to the user and to other software. Such an operating system typically includes a basic input/output system (BIOS). Communication software  304  provides communications through an external port to a network, such as the Internet, via a physical communications link by either directly invoking operating system functionality or indirectly bypassing the operating system to access the hardware for communications over the network. 
         [0046]    Application programming interface (API)  306  allows the user of the system, such as an individual or a software routine, to invoke system capabilities using a standard consistent interface without concern for how the particular functionality is implemented. Network access software  308  represents any software available for allowing the system to access a network. This access may be to a network, such as a local area network (LAN), wide area network (WAN), or the Internet. With the Internet, this software may include programs, such as Web browsers. Application software  310  represents any number of software applications designed to react to data through the communications port to provide the desired functionality the user seeks. Applications at this level may include those necessary to handle data, video, graphics, photos or text, which can be accessed by users of the Internet. The mechanism of modified bonding machine control software  800  (see  FIG. 4  and  FIG. 8 ) may be implemented within communications software  304  in these examples. 
         [0047]      FIG. 4  is an exemplary memory or storage  350  containing operating system  400 , technical information  410 , and modified bonding machine control software  800 . 
         [0048]      FIG. 5A  is bonding machine  500  having x axis motor  510 , y axis motor  520 , and z axis motor  530 . Wedge holder  540  is seen beneath microscope  550  in a downward pointing position. Wedge holder  540  is capable of rotation vertically about the x axis as is further shown in  FIG. 5B . X axis motor  510 , y axis motor  520 , and z axis motor  530  comprise a motion system. Persons skilled in the art are aware that multiple motion systems are available to provide movement of the wedge holder in three dimensions. Persons skilled in the art are further aware that bonding machine  500  can be controlled by a position control device which may be a computer such as client computers  110 ,  112  and  114  and server computers  104  and  106  in  FIG. 1  or the data processing system of  FIG. 2 . For example, referring to  FIG. 2 , input/output unit may communicate with processor  204  in response to inputs from a variety of input devices such as a keyboard (not shown), a mouse, See  FIG. 5A , or a joystick (not shown) in order to control the motion system of bonding machine  500 . 
         [0049]      FIG. 5B  is wedge holder  540 , pointing downward in a vertical plane, and weight  544 . Transfer tool  560  for holding parts to be bonded lies in a horizontal plane beneath wedge holder  540 . 
         [0050]      FIG. 5C  is a partial side view of bonding machine  500 , wedge holder  540 , modified weight  570 , and sharpened wedge  750  having sharp end  760 .  FIG. 5C  shows that weight  544  can be configured to attach at a different location and to have a different shape such as modified weight  570 . Persons skilled in the art recognize that weight  544  and modified weight  570  are only two configurations, and that many different configurations can also perform the function of applying weight to the bonding and/or cutting operations of bonding machine  500 . Furthermore, in  FIG. 5C , wedge holder  540  has rotated from a substantially downward pointing position in a vertical plane, to an elevated position substantially above a horizontal plane. 
         [0051]      FIG. 5D  is transfer tool  560  with part  562  positioned within transfer tool  560 . 
         [0052]      FIG. 6A  is a plurality of wire bonds with shorting. Specifically,  FIG. 6A  shows six bonds with first short  610 , second short  620 , and third short  630 . Spaces  640  and  650  do not have contiguous sections of adjacent wire bonds and, therefore, do not create a short. 
         [0053]      FIG. 6B  is the plurality of bonds of  FIG. 6A  with the shorts removed by cutting at first rework  612 , second rework  622 , and third rework  632 . Each of first rework  612 , second rework  622 , and third rework  632  have had shorting material cut away by modified bonding machine control software  800  (see  FIG. 8 ) and sharpened bonding wedge  750  having cutting edge  760  (see  FIG. 7B ). 
         [0054]      FIG. 7A  is bonding wedge  700  used by the ultrasonic bonding machine. As can be seen bonding wedge  700  tapers to end  710  which has a rounded or flattened surface where pressure is applied to the bond during the ultrasonic bonding process. 
         [0055]      FIG. 7B  is sharpened bonding wedge  750  which has been sharpened to create cutting edge  760  for use as a cutting tool in conjunction with modified bonding machine control software  800  that controls bonding machine  500 . 
         [0056]      FIG. 8  is a flowchart of modified bonding machine control software  800  for performing both bonding and automated rework. Modified bonding machine control software  800  starts (step  802 ) and determines whether a select bonding signal has been received (step  810 ). If so, modified bonding machine control software  800  displays a message to the operator (step  814 ) reminding the operator to check the bonder wedge. Responsive to receiving a start signal  816 , modified bonding machine control software  800  indexes the pad (step  818 ) and activates the position control device (step  820 ). Responsive to an activation of a control on an input device of the position control device (step  822 ), bonding is performed (step  826 ). If the control is not activated, then modified bonding machine control software  800  waits (step  824 ) and goes to step  822 . Modified bonding machine control software  800  determines whether to continue (step  828 ) and if so, goes to step  822 , and if not, stops (step  860 ). 
         [0057]    When modified bonding machine control software  800  determines that bonding is not to be performed, it determines whether rework is to be performed by receiving a select rework signal (step  830 ). Modified bonding machine control software  800  displays a message reminding the operator to change the bonding wedge (step  834 ) to a sharpened wedge (step  836 ), and responsive to determining that the bonding wedge has been changed to a sharpened wedge (step  836 ), indexes the pad (step  838 ) and activates the position control device (step  840 ). Responsive to activation of the control on the input device of the position control device (step  842 ), modified bonding machine control software  800  cuts short material using sharpened wedge  750  (step  846 ). If the control on the input device of the position control device is not activated, modified bonding machine control software  800  waits (step  844 ) and goes to step  842 . If the operator wants to continue (step  848 ), modified bonding machine control software  800  determines whether the operator wants to change operation to bonding (step  850 ), and if so, goes to step  810 . In one embodiment, the sharpened wedge is manually placed after manual removal of the bonding wedge by the operator. In another embodiment, the bonding machine is adapted to have a rotatable wedge arm so that the computer can automatically rotate the selected wedge into position. In another embodiment, software creates a new function and flags in the source code of the ultrasonic bonder to give it the rework capability. The new function is called OnCutShort and the new flag is called m_pshortflag. The new function and the new flag are introduced to enable the bonding machine to rework the electrical short in addition to bonding. OnCutShort function instructs the motion system to go to the prescribed position and perform cutting action on the electrical short. With the m_pshortflag, the bonder has the means of alternating between bonding mode and rework mode. The sharpened wedge cuts the bridge causing an electrical short in response to activation of the control by the operator. 
         [0058]      FIG. 9  is a flow chart of the operator process using the modified bonding machine to both bond and automated rework. Operator process  900  starts (step  902 ) and the operator accesses modified bonding machine control software  800  (step  910 ). The operator selects an action (step  912 ). If the operator does not select rework, the operator checks the bonder wedge (step  916 ), operates the input device of the position control device (step  918 ) and when ready to bond (step  920 ) activates the control on the input device of the position control device (step  922 ). If the operator wants to continue (step  924 ), the operator goes to step  918 . If the operator does not want to continue (step  924 ), the operator decides whether to change operation (step  926 ), and if so, goes to step  912 . If not, operator process  900  ends (step  950 ). 
         [0059]    When the operator decides to rework (step  914 ), the operator changes the bonding wedge to the sharpened wedge (step  928 ). The operator operates the input device of the position control device (step  930 ) to position the sharpened wedge (step  928 ), and when ready to cut (step  932 ), activates the control on the input device of the position control device (step  934 ). If more operations are desired (step  936 ), operator process goes to step  930 , and if a change in operation is not required (step  938 ), ends (step  950 ). 
         [0060]    The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions. 
         [0061]    The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.