Patent Publication Number: US-7220616-B2

Title: Methods for epoxy loc die attachment

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of application Ser. No. 09/649,160, filed Aug. 28, 2000, now U.S. Pat. No. 6,858,469, issued Feb. 22, 2005, which is a continuation of application Ser. No. 09/464,985, filed Dec. 16, 1999, now U.S. Pat. No. 6,174,752, issued Jan. 16, 2001, which is a continuation of application Ser. No. 08/907,330, filed Aug. 6, 1997, now U.S. Pat. No. 6,051,449, issued Apr. 18, 2000. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to semiconductor device manufacture and, more particularly, to methods and structures for attaching semiconductor devices to lead frames. 
   2. State of the Art: 
   During the manufacture of semiconductor devices, a semiconductor device or chip is often attached to a support, such as a lead frame. In general, a “leads-over-die” or “lead-on-chip” semiconductor device assembly has a lead frame with lead fingers that extend over the active surface of the semiconductor device supporting the semiconductor device being electrically connected to the bond pads located thereon, typically by wire bonds extending between the bond pads and the ends of the lead fingers, the other ends of the lead fingers being for attachment to other circuit components. The lead fingers extend inwardly on the lead frame to bond pads located on the active surface of the semiconductor device for connection thereto as described in U.S. Pat. No. 4,862,245 (Pashby, et al.) and U.S. Pat. No. 5,304,842 (Farnworth, et al.). 
   The semiconductor device may be attached to the lead frame using adhesively coated tape as described in U.S. Pat. No. 5,304,842 (Farnworth et al.) or by the use of hot or cold adhesives as described in U.S. Pat. No. 5,286,679 (Farnworth et al.). Use of hot or cold thermosetting or thermoplastic adhesives that have heretofore been suggested affect the processing of the semiconductor device assemblies as they require cure time for the adhesive and, in turn, cause delays in the manufacturing process to effect curing. 
   Therefore, it is desirable to have an adhesive for attaching the semiconductor device to a lead frame which has the shortest desirable cure time for the adhesive to allow the manufacturing process to proceed. 
   BRIEF SUMMARY OF THE INVENTION 
   A system for attaching a semiconductor device or die to each lead frame of a plurality of lead frames includes indexing means for supplying and advancing the plurality of lead frames for semiconductor devices in a lead frame-by-lead frame sequence. Each lead frame of the plurality of lead frames has an attaching surface to which a semiconductor device or die is to be attached. The system also includes a source of curable adhesive. Application means are configured for receiving the plurality of lead frames for semiconductor devices in the lead frame-by-lead frame sequence. The application means is connected to the source of curable adhesive for receiving curable adhesive therefrom. The application means is also configured for applying a metered amount of the curable adhesive in a preselected pattern to the application surface of each lead frame of the plurality of lead frames. The application means then supplies the lead frames with the curable adhesive applied thereto. 
   The system also includes a source of semiconductor devices to supply semiconductor devices in a semiconductor device-by-semiconductor device sequence. Attaching means are positioned relative to the source of semiconductor devices to obtain each semiconductor device in the semiconductor device-by-semiconductor device sequence. The attaching means is also positioned to receive the lead frames with the curable adhesive applied thereto in lead frame-by-lead frame sequence from the application means. The attaching means is also configured to attach one of the semiconductor devices to a corresponding lead frame in lead frame-by-lead frame sequence by urging the device into contact with the curable adhesive of each lead frame and holding each of the semiconductor devices in contact with the curable adhesive for a preselected period. That is, at least one semiconductor device is attached to each lead frame. Of course, in some applications, multiple devices may be attached to a particular lead frame configured to receive multiple semiconductor devices. Control means are provided in the system to supply operation signals to operate the various components thereof. 
   The attaching means preferably includes press means for pressing each semiconductor device into contact with a curable adhesive. The attaching means also preferably includes transfer means for transferring each semiconductor device in semiconductor device-by-semiconductor device sequence from the source of semiconductor devices to the press means. 
   The press means desirably includes heating means to heat the semiconductor device before it is pressed against the curable adhesive. The heating means is desirably a block positioned to receive each semiconductor device from the transfer means. The press means most preferably includes a press mechanism to move the block from a receiving position to receive thereon a semiconductor device into an attached position in which the block with a semiconductor device is urged into contact with the curable adhesive. The heating means desirably heats the block to a temperature from about 200° C. to about 225° C. 
   The curable adhesive is most preferably a snap curable epoxy having a cure time of substantially less than one minute and most preferably having a cure time of less than one second. In a preferable configuration, it is desirable that the curable adhesive have a filler material included therein. The filler material may be any electrochemically neutral material but is preferably a granulated Teflon®. 
   The application means is configured to apply about one milligram of the curable adhesive to each lead frame. The application means may also include a structure positioned to contact the application surface of a lead frame for applying the curable adhesive thereto. The application means may include a roller having portions positioned to selectively contact the application surface of the lead frame and the opposing surface. Alternatively, the application means may include a printing structure to contact the application surface of the lead frame or the active surface of the semiconductor device. The printing structure may include a plate, a silkscreen die, or the like. The application means may also optionally include one or more nozzles positioned to deposit the curable adhesive in a desired location on either the lead frame or the active surface of a semiconductor device. 
   In alternative configurations, the lead frames are connected one to another. The lead frames preferably have at least one, preferably two, removable edges or rails with drive perforations formed therein. Indexing means includes an electrical device connected to a drive structure which is configured to engage the perforations formed in each lead frame. 
   The attaching means preferably includes an anvil sized for positioning opposite the block and spaced therefrom to receive each lead frame of the plurality of lead frames therebetween. The anvil functions to support each lead frame as the semiconductor device is pressed against the application surface. An anvil may also be positioned opposite the application means to support each lead frame as the curable adhesive is applied thereto. 
   A method for applying curable adhesive to each lead frame and attaching a semiconductor device to each lead frame includes providing a system and operating the system to supply semiconductor devices and lead frames relative to application means and attaching means. The system is also operated to apply adhesive to a semiconductor device site of each lead frame and to then attach a semiconductor device to the adhesive at the semiconductor device site. Preferably, the adhesive is a snap curable epoxy with a cure time of about one (1) second. Even more preferably, the application means includes a pressing structure which includes a block that heats the semiconductor devices to a temperature from about 200° C. to about 225° C. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     In the drawings which illustrate what is presently regarded as preferred modes of carrying out the invention: 
       FIG. 1  is a simplified diagram of a system of the invention; 
       FIG. 2  is a printing structure of the system of the invention of  FIG. 1  for printing adhesives onto a lead frame; 
       FIG. 3  is a cross-section of  FIG. 2  taken at the section  2 - 2 ; 
       FIG. 4  shows an adhesive application nozzle for use in a system of the invention positioned relative to lead frames; 
       FIG. 5  is a perspective view of multiple adhesive application nozzles for use in a system of the invention positioned relative to lead frames; 
       FIG. 6  shows a roller printing mechanism for use in a system of the invention for applying adhesive to lead frames; 
       FIG. 7  is a partial perspective view of a roller system comparable to that shown in  FIG. 6  for applying adhesive to lead frames; 
       FIG. 8  is a perspective view of a pick-up head of the transfer mechanism for transferring devices of the system of  FIG. 1 ; 
       FIG. 9  is a simplified perspective view of a block of the application means of a system of the invention; 
       FIG. 10  is a perspective view of an indexing system for use with a system of the invention with a plurality of lead frames depicted partially cut-away and in perspective; and 
       FIG. 11  is a block diagram of a method of the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to drawing  FIG. 1 , a system  10  is illustrated for attaching a semiconductor device to each lead frame of a plurality of lead frames  12  to form a corresponding plurality of semiconductor device assemblies suitable for use in various electronic circuits. 
   The system  10  includes indexing means for supplying and advancing a plurality of lead frames  12  for semiconductor devices in a lead frame-by-lead frame sequence. More specifically, the lead frames  12  are supplied from a source  14  and are urged or moved relative to the other structures of the system  10  by a driver  16 , which is constructed to drivingly engage and move the plurality of lead frames  12  in lead frame-by-lead frame sequence, all as more fully discussed hereinafter. 
   The system  10  also includes a source of curable adhesive  18 . The source of curable adhesive  18  includes a reservoir  20  interconnected by conduit  22  to an electrically driven solenoid  24 . The solenoid  24  is connected by conductor  26  to control means, such as controller  28 , to receive operation signals therefrom to cause the solenoid  24  to move between a closed position and an opened position. The solenoid  24  may be any suitable solenoid which remains open for a selected period of time so that, given the pressure of the adhesive in the conduit  22 , a metered amount is thereby dispensed. Alternatively, some other metering device may be used that dispenses the curable adhesive  18  in metered quantities. For example, a gear pump or piston pump may be used to dispense metered amounts of curable adhesive  18 . The adhesive from the source of curable adhesive  18  proceeds through the delivery conduit  30  when the solenoid  24  is in the open position. That is, adhesive from the reservoir  20  is urged by any appropriate pressure generating arrangement, including an adhesive pump, air pressure and the like, through the conduit  22  and through a delivery conduit  30  of an application means  32 . 
   The application means  32  is configured to receive the plurality of lead frames  12  in lead frame-by-lead frame sequence. The application means  32  is connected to the source of curable adhesive  18  to receive curable adhesive  18  therefrom through the delivery conduit  30 . The application means  32  is configured and operable to apply the metered amount of curable adhesive  18  in a preselected pattern to the application surface  36  opposite a second surface  34  of each lead frame of the plurality of lead frames  12  ( FIG. 10 ). As depicted in  FIG. 1 , the application means  32  includes an applicator  38  which is operated in an up and down or in and out direction  40  by a rod  42  connected to a piston  44  positioned in a cylinder  46 . The piston  44  is shown to be fluid driven and may be operated by gas or liquid. However, a gas is preferable because of faster response times, and air is preferable because of low cost. 
   As illustrated in drawing  FIG. 1 , air under pressure is received from a reservoir  48  via a first supply line  50  through a first air solenoid  52  and a connector  54  to the cylinder  46 . A second air solenoid  56  is connected to receive air under pressure via a second supply line  58 . The second air solenoid  56  is connected by a connector  60  to the cylinder  46 . In operation, air under pressure is supplied to the reservoir  48 , for example, by an on-demand air pump  62 . That is, the air pump  62  may operate under the control of the controller  28  or upon detection of a pressure signal indicating a need to increase the pressure in the reservoir  48 . To operate the applicator  38 , the first and second air solenoids  52  and  56  are operated by operation signals received from the controller  28  via conductors  64  and  66  so that air under pressure is supplied to the underside  68  of the piston  44  in order to urge the applicator  38  upward  40  toward one of the plurality of lead frames  12 . As air under pressure is being supplied to the underside  68  of the piston  44 , the second air solenoid  56  is positioned to vent air from the top  70  of piston  44  to the atmosphere from the vent  71 . When it is desired to have the applicator  38  move away from the plurality of lead frames  12 , the first air solenoid  52  is positioned to a venting position in order to vent air through vent  72 . At the same time, air under pressure may be directed through the second air solenoid  56  via the second supply line  58  and the connector  60  to the top  70  of the piston  44  in order to urge it in a downward direction  40 . As so configured, it can be seen that the piston  44  and, in turn, the applicator  38  may be positioned precisely as desired based on the operation signals received from the controller  28  in order to effect a transfer of adhesive supplied via the delivery conduit  30  to the applicator  38  upon coordinated operation of the solenoid  24 . 
   It may be noted that a first air solenoid  52  and a second air solenoid  56  are here depicted. However, it can be seen that a three-way solenoid valve may be used in lieu of the first air solenoid and the second air solenoid. Further, other mechanisms may be used to meter air or some other suitable fluid to and from the cylinder  46  to regulate the movement of the piston  44 . 
   The system  10  illustrated in drawing  FIG. 1  also includes a source of semiconductor devices  74 , which is here illustrated only in part as a simple conveyor  76  with a plurality of semiconductor devices  78  and  79  positioned thereon. A stepper motor  80  may be operated to cause the conveyor  76  to move the semiconductor devices  78 ,  79  in a direction  82  toward the attaching means  86 . The stepper motor  80  is connected by a conductor  84  to receive operation signals from the controller  28  to, in turn, cause each device of the plurality of semiconductor devices  78 ,  79  on the conveyor  76  to index toward the attaching means  86  in coordination or in synchronization with movement of the plurality of lead frames  12 . 
   The attaching means  86  is positioned relative to the source of semiconductor devices  74  to obtain each semiconductor device of the plurality of semiconductor devices  78 ,  79  in the semiconductor device-by-semiconductor device sequence. The attaching means  86  also is positioned relative to the plurality of lead frames  12  to obtain each lead frame in lead frame-by-lead frame sequence. The attaching means  86  is also configured to attach one semiconductor device of the plurality of semiconductor devices  78 ,  79  to a corresponding one lead frame of the plurality of lead frames  12  in a lead frame-by-lead frame sequence by urging each semiconductor devices  78 ,  79  into contact with the curable adhesive positioned on the one corresponding lead frame of the plurality of lead frames  12 . The attaching means  86  further is operable to hold each semiconductor device of the plurality of semiconductor devices  78 ,  79  in contact with the curable adhesive for a preselected period of time. 
   The attaching means  86  illustrated in drawing  FIG. 1  is a simplified depiction of a mechanical system that can be assembled to be operated by a control means, such as the controller  28 , in order to effect desired operations. The attaching means  86  illustrated includes transfer means  88  which is here depicted to be a mechanism with an arm  90  attached to housing  92 , both of which are rotatable by driving a gear  96  that interconnects with an appropriate plurality of matching gear elements  97  associated with the housing  92 . More specifically, the gear  96  has teeth  95 ; and the gear elements  97  are recesses to drivingly receive the teeth  95 . In operation, the gear teeth  95  and the recesses of gear elements  97  are configured to cause the housing  92  to rotate about rod  11   2  upon activation of the stepper motor  94 . The stepper motor  94  is connected to the controller  28  by conductor  93  to receive operation signals from the controller  28  to cause the stepper motor  94  to rotate between a pick up position in which the arm  90  is operated to pick up a device of the plurality of semiconductor devices  78 ,  79  and a release position in which the semiconductor device that has been picked up is deposited on the block  110 . Of course, the relationship between the housing  92  and gear  96  may be any desired mechanical or electro-mechanical arrangement to effect operation of the housing  92  and, in turn, cause the arm  90  to rotate. 
   The arm  90  has a pickup  98  which is connected through a conduit  100  and through a solenoid  102  to a reservoir  104  and a vacuum pump  106 . The vacuum pump  106  is operated to create a desired vacuum in the reservoir  104 . Upon operation of the solenoid  102 , by receipt of operation signals from controller  28  via conductor  108 , a vacuum is applied through the conduit  100  to the pickup  98 . The conduit  100  extends inside the housing  92 , the arm  90  and extension  91  to create a vacuum to pick up each device of the plurality of semiconductor devices  78 ,  79  on the conveyor  76 . The pickup  98 , as more fully described hereinafter, is positioned proximate each semiconductor device of the plurality of semiconductor devices  78 ,  79  and picks it up by vacuum in order to reposition the semiconductor devices  78 ,  79  of the plurality of semiconductor devices  78  on a block  110 . 
   The transfer means  88  also includes a vertical positioning structure which includes a rod  112  rotatably attached to the housing  92  at the upper end  114 . The rod  112  has appropriate teeth  116 , configured to interact with drive teeth  118 , associated with a gear  120 . The gear  120  is driven by a stepping motor  122  shown in phantom. The stepping motor  122  is driven electrically by operation signals received via conductor  124  from the controller  28 . 
   In operation, the transfer means  88  can be moved upwardly and downwardly or inwardly and outwardly  126  by operation of the stepping motor  122 . In turn, the arm  90  and the pickup  98  can be moved into close proximity or contact with each semiconductor device of the plurality of semiconductor devices  78 ,  79 . When in virtual contact, appropriate vacuum can be applied by operation of the solenoid  102  so that the semiconductor devices  78 ,  79  under the pickup  98  may be picked up and raised upon operation of the stepping motor  122 . When raised upwardly  126  an appropriate distance  128 , the housing  92  may be rotated by operation of the stepper motor  94  through gear  96  and recesses of gear elements  97 . Thus, each semiconductor device of the plurality of semiconductor devices  78  and  79  may be transferred from the source of semiconductor devices  74  to the block  110 . 
   It may be recognized that the transfer means  88  herein described is simply illustrative of structure to effect the transfer of each semiconductor device of the plurality of semiconductor devices  78 ,  79  to the block  110 . A variety of chutes, slides and similar mechanisms may be devised to effect the positioning of each semiconductor device of the plurality of semiconductor devices  78 ,  79  in a sequential fashion onto block  110 . 
   The attaching means  86  also includes a press mechanism to move each semiconductor device of the plurality of semiconductor devices  78 ,  79  into contact with the curable adhesive. The illustrated mechanism has a block  110  shown in its receiving position in which it receives a semiconductor device of the plurality of semiconductor devices  78 ,  79 . The press mechanism is operable from the receiving position illustrated in drawing  FIG. 1  to an attaching position in which block  110  is positioned upwardly toward the plurality of lead frames  12  to contact the curable adhesive  132  associated with the lead frame that has been indexed to be positioned relative to the attaching means  86  and, more particularly, the press mechanism. That is, a semiconductor device, such as a semiconductor device of the plurality of semiconductor devices  78 ,  79  and, more specifically, the semiconductor device  130  shown in phantom on the block  110 , is urged upwardly to be in contact with the curable adhesive  132  that has been positioned on each lead frame of the plurality of lead frames  12  by the application means  32 . 
   The press mechanism illustrated in drawing  FIG. 1  is a hydraulically operated cylinder  134 . The hydraulic fluid in the illustrated arrangement of drawing  FIG. 1  may be air supplied from a reservoir  136  through a raised solenoid  138  and a lower solenoid  140 . That is, air pressure may be created in the reservoir  136  by operation of an air pump  144 . The air pressure may be supplied via supply lines  146  and  148  to their respective solenoids  138  and  140 . The solenoids  138  and  140  may be operated in sequence to place air pressure underneath the piston  135 . Air under pressure under the piston  135  urges the piston  135  upwardly or inwardly while solenoid  140  is operated to vent the air above the piston  135  through a vent line  150  to the atmosphere. Similarly, when the block  110  is to be lowered, the solenoid  140  is operated to provide air pressure to the top part of the piston  135  to urge it downward while the raised solenoid  138  is operated to vent the air thereunder through vent line  152 . The solenoids  138  and  140  are connected by conductors  154  and  156 , respectively, to the controller  28  to receive operation signals therefrom in order to effect movement of the piston  135  and, in turn, the block  110 . Of course, the air pressure is maintained by appropriate operation of the air pump  144  by receipt of operation signals via conductor  158  from the controller  28  or from a pressure sensor as desired. The solenoids  138  and  140  may be replaced with a three-way solenoid or by other mechanisms to port air or other hydraulic fluid. 
   The block  110  is here shown with a spring wound electrical conductor  160  extending away therefrom. The conductor  160  is spring wound so that the block  110  may easily move upward and downward as described. The spring wound conductor  160  is connected to a source of electrical power and to a heater  111  ( FIG. 9 ), positioned in the block  110 , so that the block  110  may be heated to a desired temperature. In turn, a semiconductor device, such as semiconductor device  130 , is heated in the process of moving it and holding it in place against the curable adhesive  132  to a desired temperature in order to effect the curing of the curable adhesive  132  as the semiconductor device  130  comes into contact therewith. 
   The applicator  38  of the application means.  32  is illustrated in more detail in drawing  FIGS. 2 and 3 . It receives adhesive from the delivery conduit  30  under pressure from the reservoir  20 . That is, the adhesive is urged into a distribution chamber  162  so that it may be urged out through a plurality of apertures such as aperture  164 . The top  166  of the applicator  38  has a plurality of apertures, such as aperture  164 , formed therein in a desired pattern. For example, the applicator  38  has an illustrated pattern of apertures  165 , which is desired in order to receive and hold a particular device in contact with the bumps or connector pads of a lead frame containing electrical leads in a desired pattern. The pattern of apertures  165  may be of different sizes and dimensions, as well as in different geographic configuration, all to effect the desired application of adhesive. 
   In operation, the applicator  38  will be brought into very close proximity to the application surface  36  of a particular lead frame of the plurality of lead frames  12  being indexed by driver  16 . Adhesive is urged through the delivery conduit  30  to the distribution chamber  162 . Adhesive is thereupon urged outward through the pattern of apertures  165  to contact and adhere to the application surface  36  of each lead frame of the plurality of lead frames  12 . As each lead frame of the plurality of lead frames  12  is indexed, past the applicator  38 , the applicator  38  is first retracted and then positioned upward to cause the adhesive to contact the surface of the lead frame and position the adhesive thereon in the desired pattern. 
   In drawing  FIG. 1 , there is illustrated a substantial distance between the application means  32  and the attaching means  86 . That is, time to cure could be provided by providing an appropriate or desired distance  168  between the application means  32  and the attaching means  86 . The delay, in turn, can provide time for the adhesive to begin to set up or start its curing process. 
   Referring to drawing  FIGS. 4 and 5 , an alternate arrangement of a plurality of lead frames is illustrated in which a plurality of nozzles including nozzles  178 ,  186  and  188  is shown positioned to apply adhesive to the application surface  171  of lead frames  172 ,  174  and  176 . Thus, it can be seen that the nozzles  178 ,  186 , and  188  may provide a desired pattern of adhesive  190 ,  192  and  194  as illustrated in drawing  FIG. 5 . Each nozzle  178 ,  186  and  188  is connected to the common delivery conduit  30  for further connection through the solenoid  24  to the reservoir  20  of curable adhesive. 
   Referring back to drawing  FIG. 2 , it can been seen that the applicator  38  is, in effect, a type of printing mechanism, a portion of which applies adhesive to the underside or to one surface of each lead frame of a plurality of lead frames. In lieu of patterned apertures, such as that illustrated in drawing  FIGS. 2 and 3 , a silk screen structure may be provided over the distribution chamber  162  so that the adhesive may pass therethrough in a desired pattern provided in the silkscreen surface. 
   In drawing  FIGS. 6 and 7 , a roller mechanism is illustrated. More specifically, a plurality of lead frames  196  is shown passing relative to a roller  200 . The roller  200  is driven by a stepping motor, split phase motor or the like,  202  which is connected by a conductor  204  to the controller  28  ( FIG. 1 ) to receive operation signals therefrom. The roller  200  is positioned in a container  206  which has there within a quantity of curable adhesive  208 . As the roller  200  rotates  210  through the adhesive  208 , it picks up adhesive on desired adhesive application surfaces. More specifically, as can be better seen in drawing  FIG. 7 , raised surfaces  212  and  214  are provided. A wiper  216  is positioned in close proximity to the roller  200  in order to wipe all excessive adhesive therefrom and return it to the container  206 . As seen in drawing  FIG. 7 , the wiper  216  has a first notch  218  and a second notch  220  to register with the raised surfaces  212  and  214 , respectively. The notches  218  and  220  are inset a distance  222  so that the appropriate metered amount of adhesive will remain on the surfaces  212  and  214 . In turn, as the roller  200  rotates  210  into contact with a lead frame of a plurality of lead frames  196 , adhesive on the raised surfaces  212  and  214  is deposited on each lead frame of the plurality of lead frames  196  in a desired pattern. That is, the adhesive is applied at a desired site on the desired surfaces of each lead frame. A plurality of spaced apart surfaces, such as raised surfaces  212  and  214 , may be positioned around the perimeter of the roller  200  based on the dimensions of the lead frame and the diameter of the roller  200 . 
   It may be understood that a variety of other systems and structures may be provided in order to apply the adhesive to the underside or to one surface of each lead frame of a plurality of lead frames. In addition to methods or systems herein illustrated or described, one may be able to spray or shoot adhesive in order to effect a desired contact in a preferred pattern. 
   As hereinbefore discussed, each semiconductor device of the plurality of semiconductor devices  78 ,  79  is to be transferred from the source of semiconductor devices  74  to the block  110 . The pickup  98  in drawing  FIG. 1  is better illustrated in drawing  FIG. 8 . The pickup surface  230  is here shown to be a flexible surface with a plurality of small holes  232 . The pickup surface  230  may be better described as a porous surface through which air may readily be drawn. Thus, the creation of a vacuum in the chamber  234  is transmitted external to the pickup surface  230  wherein suction upon contact with a semiconductor device of the plurality of semiconductor devices  78 ,  79  is sufficient to hold the semiconductor device against the pickup surface  230 . Such semiconductor device may then be retained against the pickup surface  230  and lifted and transferred from the conveyor  76  to the block  110 . As can be seen, the vacuum is effected through an internal channel  236  formed in the extension  238  which is connected to the pickup  98 . 
   Turning now to drawing  FIG. 10 , it can be seen that the plurality of lead frames  12 , illustrated in drawing  FIG. 1 , is here shown consisting of lead frames  240 ,  242 ,  244  and  246 . Each of the lead frames  240 ,  242 ,  244  and  246  has a plurality of lead fingers, such as lead finger  248 . Each lead frame  240 ,  242 ,  244  and  246  is secured with the others by at least one, and preferably two, outside edges or rails,  250  and  252  formed with perforations  254  to mesh with drive teeth  256  and  258  associated with driver  16 . The driver  16  is driven via axle  260  by a driver motor  266  which is connected by conductors  268  and  270  to the controller  28  in order to cause the plurality of lead frames  12  to index or to move relative to the application means  32  and the attaching means  86  as desired. As here shown, the driver  16  has an internal recessed portion  272  which allows the lead frames  12  with a respective device or devices or semiconductor chips  274 ,  276  and  278  attached thereto to pass thereover for further processing in which the lead frames  12  are separated one from the other and wherein the outside edges  252  and  250  are separated therefrom. 
   It can be seen herein and as illustrated in drawing  FIG. 11  that to operate the illustrated system, the user needs to provide a system such as that illustrated in drawing  FIG. 1 . In operation, the controller  28  is activated by positioning an on/off switch, such as on/off switch  280 , to an “on ” position. Appropriate speed or rate information is selected by operation of the dial  282  relative to an index. Other mechanisms may be used to input the speed or rate of operation that is desired. A variety of computers or similar electronic devices may be used to generate the necessary operation signals to operate the various devices herein through various electromechanical devices. The control means may be powered from an external source via a power cord  284 . 
   The control means sends the necessary operation signals in order to cause adhesive to process through the solenoid  24  and the delivery conduit  30  to the applicator  38 . The applicator  38  is moved up toward and away from the appropriate lead frames in order to apply a pattern of adhesive to one surface, more particularly, the application surface  36  of each lead frame of a plurality of lead frames  12  in a lead frame-by-lead frame sequence. Semiconductor devices, such as semiconductor devices  78 ,  79  are supplied by a source and transferred by attaching means which includes a transfer structure to a press mechanism. That is, the semiconductor devices, such as semiconductor devices  78 ,  79 , are transferred to the press mechanism which, in turn, urges each semiconductor device in semiconductor device-by-semiconductor device sequence to and in contact with the patterned adhesive. 
   It should be noted that the preferred adhesive is a snap cure adhesive available from Quantum Materials, Inc. of San Diego, Calif. A preferred adhesive has been determined to be a snap cure epoxy which is known as the  505  epoxy formula. The desired snap cure epoxy is preferably defined to have a cure time of substantially less than one minute and preferably less than one second when it is applied with a block  110  that is preferably at a temperature between 200° C. and 225° C. That is, the block  110  is heated via conductor  160  to expedite the curing when the semiconductor devices are being attached to the attaching surface of each of the plurality of lead frames. 
   The snap cure epoxy and, more particularly, the  505  epoxy are preferred in metered amounts of about 1 milligram for every device site or for every device that is being applied to the lead frame. In some applications, multiple devices may be applied. In others, a single device may be applied. 
   In preferred arrangements, the epoxy applied preferably contains a non-conductive filler which may be made of Teflon®, Teflon® granular material or flakes and may be mixed into the adhesive in order to function as a filler to achieve the desired tackiness and cure time. 
   The application means is preferably operated to apply the necessary amount of adhesive at each semiconductor device site. When a semiconductor device is pressed against the semiconductor device site, the adhesive is pressed to have a thickness of approximately 0.001 inch. 
   Other curable adhesives comparable to the 505 epoxy that are snap curable in one minute or less, and preferably one second or less, may be suitable. 
   Mechanisms for applying adhesive may include wiping mechanisms or other devices to clean away excess material to avoid contaminating different lead frames with excess adhesive material. Those skilled in the art, will recognize that the embodiments are merely illustrative of the principles of the invention.