J-lead conditioning method and apparatus

An electronic device package lead conditioning method and system corrects bowed-in J-leads (36) of an electronic device package (30) by inserting between a bowed-in J-lead (36) and electronic device package (36) a comb-like tooth (42) having a graduating-width edge, the graduating width edge graduating from a minimum width (112) to a maximum width (114). The minimum width permits the graduating width edge (112) to be inserted into a space (110) separating the bowed-in J-lead (36) from electronic device package (30). The maximum width (114) at least equals the width of a desired spacing for the bowed-in J-lead (36) from the electronic device package (30) for correcting for the bowed-in-condition of the bowed-in J-lead (36).

This application claims priority under 35 U.S.C. .sctn.119(e)(1) of 
Provisional Application No. 60/026,806, filed Sep. 30, 1996. 
TECHNICAL FIELD OF THE INVENTION 
The present invention relates to a system and method for processing 
electronic devices and, more particularly, to a lead conditioning system 
for properly adjusting electronic component package leads, and even more 
particularly, the present invention relates to a method and system for 
correcting bowed-in J-leads of an electronic device package. 
BACKGROUND OF THE INVENTION 
Unintended deformation of electronic component package leads, such as 
electronic component package J-leads, is a well-known problem in the 
electronics industry. In the case of J-leads, this problem has been dealt 
with by manually manipulating the J-leads back into their correct shape 
when deformation occurs. The problem with this method, however, is that as 
electronic component package processing is becoming more automated, manual 
manipulation becomes comparatively less efficient. Manual working and 
handling of electronic component packages for J-lead conditioning, 
therefore, is becoming less desirable. 
There also are systems that correct automatically for J-lead bow-in. For 
example, some systems attempt to correct bow-in by pushing the tail end of 
the J-lead out away from the electronic package center. While this type of 
system works well for many instances of bow-in, it often yields 
inconsistent results. 
Consistent results are desired in J-lead bow-in connection for a number of 
reasons. For example, it may be desirable for a lead to have a high degree 
of flexibility to accommodate wide temperature ranges within which the 
electronic device may separate. Because the bow-in condition limits 
flexibility, a J-lead solder joint could break during the extreme 
temperatures that the component may experience. If a solder-joint breaks, 
the J-lead could move. This has the potential of placing an existing over 
coating material between the lead and the underlying connection pad, 
resulting in an open circuit at the J-lead. 
SUMMARY OF THE INVENTION 
There is a need for a lead conditioning system that effectively corrects 
for a bowed-in lead condition on a J-lead equipped electronic device 
package. 
In accordance with the present invention, a J-lead conditioning system is 
provided that substantially eliminates or reduces disadvantages and 
problems associated with previously developed lead conditioning systems 
that either cannot correct for bowed-in J-leads or that inefficiently 
perform bowed-in J-lead conditioning. 
More specifically, the present invention provides a J-lead conditioning 
system for conditioning bowed-in J-leads of an electronic component 
package. The present invention includes a comb-toothed device that inserts 
between a bowed-in lead and the electronic device package. The 
comb-toothed device includes graduating thickness comb-like teeth, each of 
which includes a beginning edge of a minimum thickness that graduates from 
the minimum thickness to a maximum thickness. The minimum thickness 
comb-like teeth can be inserted alongside a bowed-in J-lead and into the 
space separating the bowed-in J-lead from the remainder of the electronic 
device package. The maximum thickness at least equals the desired 
clearance of the bowed-in J-lead from the electronic device package. The 
comb-like teeth engage the bowed-in lead with the graduating width edge of 
the tool to move the bowed-in lead from a bowed-in position to a desired 
aligned position. 
A technical advantage of the present invention is its ability to be used 
with pre-existing systems and as only a single additional step of a 
process for otherwise conditioning the electronic device J-leads. This 
makes using the present invention only consume a minimal additional time 
in correcting for bowed-in J-leads. 
Another technical advantage of the present invention is that, while it 
conditions bowed-in J-leads of an electronic device package, it does not 
inadvertently affect properly positioned and aligned J-leads.

DETAILED DESCRIPTION OF THE INVENTION 
Preferred embodiments of the present invention are illustrated in the 
FIGUREs like numerals being used to refer to like and corresponding parts 
of the various drawings. 
FIG. 1 illustrates one embodiment of a lead conditioning system for using 
the present invention to correct bowed-in J-leads of an electronic device 
package. Lead conditioning system 10 that provides feed mechanism 12 for 
feeding numerous electronic device packages that tube 14 holds. In 
operation, electronic device packages pass from tube 14 along rail 16 
where bowed-in J-lead conditioning device 18, which takes the form of one 
of the various embodiments here described, corrects for bowed-in J-leads. 
Tube 22 receives the conditioned electronic device packages that after 
passing through J-lead conditioning device 18 have corrections for both 
bowed-in J-leads and for other defects. Cabinet 24 holds electrical 
circuitry to support the operation of lead conditioning system 10. Cabinet 
24 is conventional in nature and serves as the primary housing for lead 
conditioning system 10. Control panel 26 permits the control of lead 
conditioning system 10. 
Two lead conditioning systems that can effectively accommodate the present 
embodiment of the invention are the Texas Instruments AT4140 and AT4160 
PLCC Lead Conditioning Systems. Both of these systems provide a fully 
automatic system for correcting bent lead, lead sweep, lead pitch, and 
package stand-off problems for PLCC products. The AT4140 is a gravity fed 
lead conditioning system as appearing in FIG. 1. The AT4160, on the other 
hand, is a "pick and place" machine that includes a mechanical apparatus 
for moving the electronic device packages both before and after 
correction. 
Although not shown in FIG. 1, lead conditioning system 10, may have various 
differing devices that appear along rail 16 for sequentially performing 
different lead conditioning operations. In the event that the other lead 
conditioning operations are to be performed, the present invention may be 
employed as only one additional step in the J-lead conditioning 
process-the other steps occurring, as appropriate, before and after 
correction for the bowed-in condition. 
FIG. 2 is a partially cut-away view of a bowed-in lead conditioning device 
18 of the present lead conditioning system. FIG. 2 shows electronic device 
package 30 that includes J-lead-sets 32 and 34. Notice that J-lead 36 is 
bowed-in. This means that J-lead 36 has been compressed or otherwise 
deformed to be closer to the side of electronic package 30 than its design 
specifies. J-lead conditioning, device, when used with lead conditioning 
system 10 or a similar system, corrects this problem without adversely 
affecting or threatening to affect other J-leads which may be not 
bowed-in. 
J-lead conditioning device 18 includes J-lead centering device 38 that 
first contacts electronic device package 30. Teeth 40 of J-lead alignment 
plate 38 position J-lead conditioning device 18 so that comb-like teeth 42 
of comb-toothed device 44 may engage electronic device package 30 
alongside the J-lead and into the space separating the J-leads from the 
side wall of the electronic device package. 
Three alignment rods 46, 48, and 50 pass through middle block section 52 to 
hold alignment plate 38 in place. Alignment rods 46, 48, and 50 include 
heads 54, 56, and 58 respectively that respective channels 60, 62, and 64 
of upper-block section 66 hold. Springs 68, 70, and 72 respectively, apply 
spring pressure to alignment rods 46, 48 and 50. Screws 74, 76, and 78 
hold respective springs 68, 70, and 72 in place and, via screw threads may 
vary their position. This permits adjusting the compression and, 
therefore, the pressure extended by springs 68, 70, and 72. Note that 
alignment rod 48 and its associated channel 63, head 56, spring 70 and 
screw 76 are of greater dimensions than the other alignment rods and 
associated components. This may allow, for example, a vacuum channel 82 to 
exist in screw 76 and channel 84 to exist in alignment rod 48. Vacuum 
channels 82 and 84 may permit a vacuum draw to pass through alignment rod 
48 and through alignment plate 40, to hold an electronic device package 
firmly against alignment plate 40 using vacuum force. While the preferred 
embodiment does not use such vacuum channels, they are possible and fully 
within the scope of the present invention. 
Middle block section 52 holds comb-tooth device 44 using block plate 74. 
Screws 76 and 78 and swivel pin 80 hold comb-tooth device 44 in place. One 
such block plate 74 retains a comb-toothed device 44 to middle block 
section 52 for each side of the device. 
FIG. 3 is an exploded view of the middle block portion 52 for a two-sided 
embodiment of the present invention. At the top of middle block portion 52 
holes 86, 88 and 90 that slidably receive pins 46, 48 and 50 respectively. 
Pins 46, 48 and 50 pass through middle block portion 52 to engage holes 
92, 94, and 96 respectively. 
FIG. 3 also demonstrates how plate 74 secures comb-toothed alignment device 
44 in position along middle block portion 52. Plate 74 fastens via screws 
76 (not shown) and 78 to upper ledge 98 of middle block portion 52. 
Comb-toothed alignment device 44 fits beneath upper ledge 98 and is 
secured to lower segment 100 by swivel pin 80 that passes through the 
second plate 74 and rubber bushing 104. An equivalent structure appears on 
the opposite side of middle block portion 52. Rubber bushing 104 holds 
comb-toothed device 44 secure, while permitting a slight degree of motion. 
This allows for variation in package width and positions. 
FIGS. 4A and 4B show operation of the present embodiment for first 
positioning electronic device package 30 J-leads in proper position with 
respect to bowed-in-J-lead conditioning device 18 and then engaging the 
J-leads with comb-teeth 42 of comb-toothed alignment device 44. Thus, as 
FIG. 4A first shows, alignment teeth 40 of alignment plate 38 fit between 
J-leads 32 of electronic device package 30. Alignment teeth 40 have a 
pointed edge and wide base to accommodate a large degree of error in the 
original positioning of the electronic device package. 
In other words, the present invention uses a wedging action that 
comb-toothed alignment device 44 causes and the movement of comb-toothed 
alignment device 44 follows the profile of electronic device package 30 to 
provide a consistent clearance between the J-lead and electronic device 
package 30. Note that alignment plate 38 prevents damage to the J-leads, 
but is not essential for practicing the present invention. After 
engagement of alignment plate 38, however, what may have been a large 
error has been essentially eliminated. This permits the second stages of 
the bowed-in J-lead conditioning process. 
FIG. 4B shows this next stage in which comb-teeth 42 of comb-tooth 
alignment device 44 insert between J-leads 32. Note that without the 
initial alignment stage of FIG. 4B, comb-teeth 42 possibly could hit one 
or more J-leads to either damage comb-toothed alignment device 44, the 
J-lead, or both. 
FIGS. 5 and 6 show the bottom sides of two embodiments of alignment plate 
38 of the present invention. In FIG. 5, alignment plate 38 is useful for 
aligning an electronic device package having J-leads on all four of its 
sides. The FIG. 6 device is for the two-sided J-lead electronic device 
package such as that appearing in FIGS. 1 through 4. 
FIGS. 7A through 7D show operation of the present embodiment for correcting 
a bowed-in J-lead condition. In FIG. 7A, comb-toothed alignment device 44 
moves in a downward direction to engage J-leads 32, 34 and 36 of 
electronic device package 30. Notice that J-lead 36 is bowed-in, having 
been for some reason or another, pushed inward to create less than an 
optimal distance between stem 106 and side wall 108. FIG. 7B shows the 
downward motion of teeth 42 in space 110 that separates adjacent J-leads. 
Although not shown in FIGS. 7A through 7D, alignment plate 38 would have 
initially aligned J-leads 32, 34, and 36 to permit proper initial 
insertion into space 110. 
Each of the comb teeth 42 includes a minimum thickness edge 112 that 
permits insertion to space 110. This is true even for the instance of a 
bowed-in J-lead. Each of the comb-like teeth 42 also is preferably more 
narrow at the tip that inserts between adjacent J-leads. This even further 
accommodates for initial misalignment between comb-toothed alignment 
device 44 and J-leads 32, 34 and 36. 
Once the minimum thickness of comb-toothed alignment device 44 inserts 
between the bowed-in J-lead and the electronic device package, 
comb-toothed alignment device 44 starts to pry the bowed-in J-lead into 
its proper position, the spacing and size of the comb teeth 42 are such 
that inserting comb-toothed alignment device 44 downward to the correct 
stop position, as FIG. 7C shows, corrects the bowed-in condition. 
Accordingly, as FIG. 7D illustrates, J-lead 36 is in proper alignment with 
J-leads 32 and 34 without the previously noted bowed-in condition. 
In the preferred embodiment of the invention, the amount of bow-in 
correction may be adjusted by changing the depth to which comb-toothed 
alignment device 44 is inserted. In particular, the preferred embodiment 
may include a mechanism providing an adjustable height stop or other 
mechanism for controlling the amount of travel for comb-toothed alignment 
device 44. 
The downward force for conditioning the J-leads may be supplied by a motor 
or other device. In particular, an appropriate feed mechanism may be 
employed with lead conditioning system 10 (FIG. 1) so that electronic 
device packages 30 may be automatically fed to J-lead conditioning 
apparatus 18. These adaptions may use known techniques of machine 
automation and control to achieve these purposes. 
Although the invention has been described in detail herein with reference 
to the illustrative embodiments, it is to be understood that this 
description is by way of example only and is not to be construed in a 
limiting sense. It is to be further understood that numerous changes in 
the details of the embodiments of the invention and additional embodiments 
of the invention will be apparent to, and may be made by, persons of 
ordinary skill in the art having reference to this description. It is 
contemplated that all such changes and additional embodiments are within 
the spirit and true scope of the invention as claimed below.