U.S. patent application number 11/066875 was filed with the patent office on 2006-08-31 for integrated circuit package and method of manufacture thereof.
This patent application is currently assigned to Texas Instruments Incorporated. Invention is credited to William David Boyd, Bernhard Lange.
Application Number | 20060192273 11/066875 |
Document ID | / |
Family ID | 36927768 |
Filed Date | 2006-08-31 |
United States Patent
Application |
20060192273 |
Kind Code |
A1 |
Lange; Bernhard ; et
al. |
August 31, 2006 |
Integrated circuit package and method of manufacture thereof
Abstract
An integrated circuit (IC) package 100 comprises an IC 102 and
leads 104 coupled to the IC. Each lead has a first end 106
configured to be coupled to the integrated circuit and a second end
108 configured to pass through one of a plurality of mounting holes
110 extending through a mounting board 112. The leads comprise at
least one positioning lead 114 comprising a stop 118 being a
continuous part of the positioning lead and having a lateral
dimension 120 greater than a diameter 122 of a first hole 124 of
the plurality of mounting holes. The leads further comprise at
least one non-positioning lead 116 having a continuous uniformly
shaped body 130 with a lateral dimension 132 less than a diameter
134 of a second hole 136 of the plurality of mounting holes. The
stop limits an extension of the non-positioning lead through the
second hole.
Inventors: |
Lange; Bernhard; (Garland,
TX) ; Boyd; William David; (Frisco, TX) |
Correspondence
Address: |
TEXAS INSTRUMENTS INCORPORATED
P O BOX 655474, M/S 3999
DALLAS
TX
75265
US
|
Assignee: |
Texas Instruments
Incorporated
Dallas
TX
|
Family ID: |
36927768 |
Appl. No.: |
11/066875 |
Filed: |
February 25, 2005 |
Current U.S.
Class: |
257/666 ;
257/E23.048 |
Current CPC
Class: |
H05K 2201/10689
20130101; H01L 24/49 20130101; H05K 2201/10787 20130101; H01L
2924/207 20130101; H01L 2224/45099 20130101; H01L 2224/45015
20130101; H01L 2924/00 20130101; H05K 2201/10871 20130101; H01L
2924/01079 20130101; H01L 2924/01046 20130101; H01L 2224/49175
20130101; H05K 3/308 20130101; H01L 2924/14 20130101; H01L
2924/00014 20130101; H01L 2924/00014 20130101; H01L 2924/14
20130101; H01L 2924/00014 20130101; H01L 23/49555 20130101 |
Class at
Publication: |
257/666 |
International
Class: |
H01L 23/48 20060101
H01L023/48 |
Claims
1. An integrated circuit package, comprising: an integrated
circuit; and leads coupled to said integrated circuit, each of said
leads having a first end configured to be coupled to said
integrated circuit and a second end configured to pass through one
of a plurality of mounting holes extending through a mounting
board, and wherein said leads comprise: one or more positioning
lead comprising a stop being a continuous part of said positioning
lead and having a lateral dimension greater than a diameter of a
first hole of said plurality of mounting holes, and one or more
non-positioning lead having a continuous uniformly shaped body with
a lateral dimension less than a diameter of a second hole of said
plurality of mounting holes, wherein said stop limits an extension
of said non-positioning lead through said second hole.
2. The integrated circuit package as recited in claim 1, further
comprises a mold encompassing said integrated circuit and holding a
heat sink above a top surface of said integrated circuit.
3. The integrated circuit package as recited in claim 1, further
comprises a mold encompassing said integrated circuit, wherein said
first end is encompassed by said mold and at least a portion of
said stop is below a bottom surface of said mold.
4. The integrated circuit package as recited in claim 3, wherein
said stop is configured to hold said bottom surface above said
mounting board by a fixed distance.
5. The integrated circuit package as recited in claim 1, wherein
said stop is configured to prevent a segment of said positioning
lead from passing through said first hole, said segment being
between said first end and said stop.
6. The integrated circuit package as recited in claim 1, wherein
said stop comprises a bend in said positioning lead.
7. The integrated circuit package as recited in claim 6, wherein
said bend has an interior angle ranging from about 70 to about 110
degrees.
8. The integrated circuit package as recited in claim 1, wherein
said stop comprises an increased width in said positioning
lead.
9. The integrated circuit package as recited in claim 8, wherein
said increased width is at least about 5 percent greater than said
diameter of said first hole.
10. The integrated circuit package as recited in claim 1, further
comprises at least two of said positioning leads, wherein said
positioning leads are corner leads being coupled to opposing
corners of said integrated circuit.
11. The integrated circuit package as recited in claim 1, further
comprises at least four of said positioning leads, wherein said
positioning leads are corner leads each one of said positioning
leads being coupled to different corners of said integrated
circuit.
12. The integrated circuit package as recited in claim 1, wherein
said stop is located on a side of said positioning lead that is
non-proximal to an adjacent non-positioning lead.
13. The integrated circuit package as recited in claim 1, wherein
said non-positioning lead comprises short non-positioning leads
interleaved with long non-positioning leads, both said short and
long non-positioning leads being coupled to a same side of said
integrated circuit.
14. A method of manufacturing an integrated circuit package,
comprising: forming a plurality of leads, each of said leads having
a first end configured to be coupled to an integrated circuit and a
second end configured to pass through one of a plurality of holes
extending through a mounting board, including: forming a
positioning lead comprising a stop being a continuous part of said
positioning lead and having a lateral dimension greater than a
diameter of a first hole of said plurality of mounting holes; and
forming a non-positioning lead having a continuous uniformly shaped
body having a lateral dimension less than a diameter of a second
hole of said plurality of mounting holes, wherein said stop limits
an extension of said non-positioning lead through said second
hole.
15. The method recited in claim 14, wherein forming said
positioning lead comprises: forming a layout pattern on a metal
sheet, wherein said layout pattern comprises a lead layout pattern
for said least one positioning lead having said stop; and removing
portions of said metal sheet that are outside of said layout
pattern to thereby form a lead frame comprising said at least one
positioning lead.
16. The method as recited in claim 15, wherein said stop comprises
a width greater than that of an adjacent portion of said
positioning lead, said adjacent portion being configured to pass
through said first hole.
17. The method of fabrication recited in claim 14, wherein forming
said positioning lead comprises: forming a lead layout pattern on a
metal sheet, wherein said layout pattern comprises a lead layout
pattern for a plurality of uniformly shaped leads; removing
portions of said metal sheet that are outside of said layout
pattern to thereby form said leads that are uniformly-shaped leads;
and bending at least one of said uniformly shaped leads to form
said positioning lead comprising said stop.
18. The method as recited in claim 17, wherein said stop comprises
a bend with an interior angle ranging from about 70 to about 110
degrees.
19. The method as recited in claim 14, further includes bending
said positioning lead to configure said stop to be below a bottom
surface of a mold encompassing said integrated circuit.
20. The method as recited in claim 14, further comprising coupling
a heat sink to a top surface of said integrated circuit; and
encompassing said integrated circuit in a mold.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention is directed to integrated circuit
packaging and a method for manufacturing an integrated circuit
package.
BACKGROUND OF THE INVENTION
[0002] After the manufacture of integrated circuits on a
semiconductor wafer there remains the need to protect the
individual integrated circuit dies from damage and to provide
connections to other devices. The enclosure surrounding and
connections to the integrated circuit is referred to as an
integrated circuit package. Numerous consumer electrical products
demand integrated circuit packages that are subject to high cost
constraints. As integrated circuits grow in complexity and
capabilities, however, conventional integrated circuit packages
have inadequate thermal management and connectivity requirements.
Additionally, today's complex integrated circuits are highly
susceptible to damage by mechanical stresses that can be imparted
from the surface that the integrated circuit package is mounted
on.
[0003] Accordingly, what is needed in the art is an integrated
circuit package that allows a large number of connections to the
integrated circuit, facilitate heat transfer away from the
integrated circuit, and protect the integrated circuit from
mechanical stresses.
SUMMARY OF THE INVENTION
[0004] To address the above-discussed deficiencies of the prior
art, the present invention provides in one embodiment, an
integrated circuit package. The integrated circuit package
comprises an integrated circuit and leads coupled to the integrated
circuit. Each of the leads have a first end configured to be
coupled to the integrated circuit and a second end configured to
pass through one of a plurality of mounting holes extending through
a mounting board. The leads comprise at least one positioning lead
comprising a stop being a continuous part of the positioning lead
and having a lateral dimension greater than a diameter of a first
hole of the plurality of mounting holes. The leads further comprise
at least one non-positioning lead having a continuous uniformly
shaped body with a lateral dimension less than a diameter of a
second hole of the plurality of mounting holes. The stop limits an
extension of the non-positioning lead through the second hole.
[0005] Another aspect of the present invention is a method of
manufacturing an integrated circuit package. The method comprises
forming a plurality of leads. Each of said leads having first and
second ends configured as described above. Forming the plurality of
leads includes forming positioning and non-positioning leads
configured as described above.
[0006] The foregoing has outlined preferred and alternative
features of the present invention so that those skilled in the art
may better understand the detailed description of the invention
that follows. Additional features of the invention will be
described hereinafter that form the subject of the claims of the
invention. Those skilled in the art should appreciate that they can
readily use the disclosed conception and specific embodiments as a
basis for designing or modifying other structures for carrying out
the same purposes of the present invention. Those skilled in the
art should also realize that such equivalent constructions do not
depart from the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] For a more complete understanding of the present invention,
reference is now made to the following detailed description taken
in conjunction with the accompanying FIGUREs. It is emphasized that
various features may not be drawn to scale. In fact, the dimensions
of various features may be arbitrarily increased or reduced for
clarity of discussion. In addition, it is emphasized that some
circuit components may not be illustrated for clarity of
discussion. Reference is now made to the following descriptions
taken in conjunction with the accompanying drawings, in which:
[0008] FIG. 1 illustrates a perspective view of one embodiment of
an integrated circuit package of the present invention;
[0009] FIG. 2 presents a plan view of exemplary integrated circuit
package of the present invention;
[0010] FIG. 3 presents a plan view of another embodiment of the
integrated circuit package of the present invention;
[0011] FIGS. 4-8 illustrate plan views of selected steps in an
exemplary method of manufacturing an integrated circuit package
following the principles of the present invention; and
[0012] FIGS. 9-13 illustrate plan views of selected steps in an
alternative method of manufacturing an integrated circuit package
of the present invention.
DETAILED DESCRIPTION
[0013] FIG. 1 presents a perspective view of one embodiment of the
present invention, an integrated circuit package 100. The
integrated circuit package 100 comprises an integrated circuit 102
and leads 104 coupled to the integrated circuit 102. The integrated
circuit 102 can comprise any conventional microelectronic device,
such as standard linear and logic products, digital signal
processors, microprocessors, digital and analog devices, high
frequency and higher power devices, and comprise either large or
small chip sizes.
[0014] Each of the leads 104 have a first end 106 configured to be
coupled to the integrated circuit 102 and a second end 108
configured to pass through one of a plurality of mounting holes 110
extending through a mounting board 112. The leads 104 comprise at
least one positioning lead 114 and at least one non-positioning
lead 116. The positioning lead 114 comprises a stop 118. The stop
118 is a continuous part of the positioning lead 114 and has a
lateral dimension 120 that is greater than a diameter 122 of a
first hole 124 of the plurality of mounting holes 110. The term
lateral dimension 120 as used herein refers to any number of
directions 126, 127 that is parallel with a plane 128 of the
mounting board 112. The non-positioning lead 116 has a continuous
uniformly shaped body 130 with a lateral dimension 132 less than a
diameter 134 of a second hole 136 of the plurality of mounting
holes 110. The stop 118 limits an extension of the non-positioning
lead 116 through the second hole 136.
[0015] The first ends 106 of the leads 104 can be configured for
direct or indirect coupling to the integrated circuit 102. For the
embodiment shown in FIG. 1, bonding wires 138 facilitate the
indirect coupling of the first ends 106 of the leads 104 to bond
pads 140 on the integrated circuit 105. Of course, direct coupling
by placing the first ends 106 in contact with the bond pads 140 is
also within the scope of the present invention. Similarly, the
second ends 108 of the leads 104 can be coupled directly or
indirectly to metal lines 142 of a printed circuit 144. For
instance, as shown in FIG. 1, the second ends 108 of both the
positioning lead 114 and non-positioning lead 116 are directly
coupled via solder to the metal lines 142 of the printed circuit
144. For the embodiment shown in FIG. 1, the metal lines 142 are
patterned on a bottom side 146 of the mounting board 112, whereas
the integrated circuit package 100 is surface mounted on a topside
148 of the mounting board 112
[0016] With continuing reference to FIG. 1, the integrated circuit
package 100 can further comprise a mold 150, a heat sink 152 and a
mounting pad 154. In preferred embodiments the integrated circuit
102 is coupled to the mounting pad 154 using an adhesive such as
epoxy. The mold 150, which can also be made of an epoxy,
encompasses the integrated circuit 102. In addition to protecting
the integrated circuit 102 against harmful environmental
conditions, the mold 150 securely holds the leads 104, bond wire
138 and heat sink 152 at appropriate locations relative to the
integrated circuit 102. For instance, the first end 106 of the
leads 104 is encompassed by the mold 150, and at least a portion of
the heat sink 152 is surrounded by the mold 150.
[0017] In some preferred embodiments, such as shown in FIG. 1, the
mold 150 holds the heat sink 152 above a top surface 156 of the
integrated circuit 102. Locating the heat sink 152 over the
integrated circuit 102 is advantageous in embodiments where the
integrated circuit package 100 is held above the plane 128 of the
mounting board 112 and the heat sink 152 does not contact the
mounting board 112. In these cases, there is greater dissipation of
heat generated from the active integrated circuit 102 as compared
to a heat sink that is under the integrated circuit 102.
[0018] The stop 118 of the positioning lead 114 is configured to
hold the integrated circuit package 100 above the plane 128 of the
mounting board 112 by a fixed distance 158, for example, about 100
microns to about 2000 microns. Holding the integrated circuit
package 100 above the plane 128 of the mounting board 112
advantageously protects the integrated circuit 102 against damage
from mechanical stresses that can otherwise be imparted from the
mounting board 112 to the integrated circuit package 100.
Preferably, the stop 118 is configured to prevent a segment 160 of
the positioning lead 114 from passing through the first hole 124.
As illustrated in FIG. 1, the segment 160 is between the first end
106 and the stop 118.
[0019] The stop can be configured to have a number of different
shapes to provide the lateral dimension greater than the diameter
of its corresponding mounting hole. For example, as illustrated in
FIG. 1, the stop 118 of the positioning lead 114 comprises an
increased width 162 in one direction 126. In some preferred
embodiments, the increase width 162 is at least about 5 percent
greater than the diameter 122 of the first hole 124. Of course,
other configurations where the increased width is in a different
direction 127, or several directions that are parallel to the plane
of the mounting board 112, are also within the scope of the present
invention.
[0020] As another example, the positioning lead can have a stop
that comprises a bend in the positioning lead. For instances, FIG.
1 shows a second positioning lead 164 having a stop 166 that
comprises a bend in the second positioning lead 164. In some
preferred embodiments, the stop 166 has an interior angle 168
ranging from about 70 to about 110 degrees, although other ranges
of angles and type types of bends can be used. Of course,
positioning lead having stops that comprise multiple bends, or both
and increased width and a bend are also within the scope of the
present invention.
[0021] With continuing reference to FIG. 1, to present additional
aspects of the present invention, FIG. 2 presents a plan view of
exemplary integrated circuit package 200. The same reference
numbers used in FIG. 1 are used to label analogous components of
the integrated circuit package 200. For clarity, the leads 104 and
mold 150 are depicted as being semitransparent and transparent,
respectively.
[0022] As shown in FIG. 2, to hold the integrated circuit package
200 above the plane 128 of the mounting board 112, it is preferable
to have at least two positioning leads 205, 210. In some cases,
such as shown in FIG. 1, the positioning leads 114, 164 are coupled
to the same side of the integrated circuit 102. It is more
preferable, however, for the two positioning leads 205, 210 to be
coupled to opposing sides of the integrated circuit 102, as shown
in FIG. 2. Locating the positioning leads 205, 210 on opposing
sides of the integrated circuit 102 more stably holds the
integrated circuit package 100 at the fixed distance 158, as
compared to having positioning leads on only one side of the
integrated circuit 102. Configuring the two positioning leads 205,
210 as corner leads, such as shown in FIG. 2, is even more
desirable, as this configuration further stabilizes the seating of
the integrated circuit package 200 on the mounting board 112.
Additional stability can be gain by locating the corner positioning
leads 205, 210 in opposing diagonal corners of the integrated
circuit 102, such as shown in FIG. 2.
[0023] In some instances, configuring the positioning leads 205,
210 as corner leads provides the additional benefit of reducing the
pitch 215 between the corner positioning lead 210 and an adjacent
interior non-positioning lead 220. Reducing the pitch 215 between
the corner positioning lead 210 and the adjacent interior
non-positioning lead 220 is facilitated by locating the stop 118 on
a side of the positioning lead 210 that is non-proximal to the
adjacent non-positioning lead 220, as shown in FIG. 2.
[0024] Corner positioning leads 205, 210 can be advantageously used
in combination with a variety of surface mounting configurations to
reduce the interior lead pitch 225 and thereby increase the number
of connections to the integrated circuit 102. For instance, as
shown in FIG. 2, the interior non-positioning leads 230 are
extended through mounting holes 110 that are arranged in a
staggered configuration. In some cases, to facilitate extension of
leads 104 through the staggered mounting holes 110, shorter
non-positioning leads 235 are interleaved with longer
non-positioning leads 240 on the same side of the integrated
circuit 102. Of course, short and long positioning leads 205, 210
can also be using in a staggered hole configuration.
[0025] With continuing reference to FIG. 1, FIG. 3 presents a plan
view of another embodiment of the integrated circuit package 300 of
the present invention. Again, the same reference numbers as used in
FIG. 1 are used to label analogous components of the integrated
circuit package 300. FIG. 3 presents a preferred embodiment of the
integrated circuit package comprising at least four positioning
leads 305, 310, 315, 320. Preferably, the positioning leads 305,
310, 315, 320 are corner leads, where each one of the positioning
leads 305, 310, 315, 320 are coupled to different corners of the
integrated circuit 102. FIG. 3 illustrates the positioning leads
305, 310, 315, 320 and non-positioning leads 325 being extended,
below the plane of view, through mounting holes 110 that are
arranged in a straight-line configuration. Of course, a staggered
arrangement of mounting holes 110, similar to that presented in
FIG. 2 could also be used.
[0026] For clarity, only a limited number of leads 104 are depicted
in the embodiments of the integrated circuit packages illustrated
in FIGS. 1-3. It should be understood, however, that the integrated
circuit package of the present invention could contain any number
of leads found in a conventional surface-mount integrated circuit
packages. For instance, integrated circuit packages having from two
to three hundred leads are known in the industry. Also, the
integrated circuit package can be any number of conventional type
of lead-containing package, including plastic dual in-line
integrated circuit packages (PDIP), small outline integrated
circuits (SOICs), quad flat packages (QFPs), thin QFPs (TQFPs),
Small Shrink Outline Plastic packages (SSOP), thin SSOPs (TSSOPs),
thin very small-outline packages (TVSOPs), or other packages known
to those skilled in the art. The leads can be made of any
conventional ductile conductive material used for through-hole
leads. Non-limiting examples of such materials include gold,
silver, copper and alloys thereof. In some cases, the leads are
plated with tin, nickel, palladium or similar materials to improved
adhesion to solder.
[0027] Another aspect of the present invention is a method of
manufacturing an integrated circuit package. The method of
manufacturing an integrated circuit package can be used to produce
any of the embodiments of the integrated circuit package presented
in FIGS. 1-3 and discussed above.
[0028] FIGS. 4-8 illustrate plan views of selected steps in an
exemplary method of manufacturing an integrated circuit package 400
following the principles of the present invention. Turning first to
FIG. 4, presented is a plan view of a partially completed
integrated circuit package 400 after forming a layout pattern 405
on a metal sheet 410. Any conventional process, such as
photolithography can be used to define the layout pattern 405 on
the metal sheet 410. The layout pattern 405 comprises a lead layout
pattern 415 for at least one positioning lead having a stop.
[0029] With continuing reference to FIG. 4, FIG. 5 shows the
partially completed integrated circuit package 400 after removing
portions of the metal sheet 410 that are outside of the layout
pattern 405 to thereby form a lead frame 505 comprising at least
one positioning lead segment 510 having a stop 515. As illustrated
in FIG. 5, the stop 515 is configured to be a continuous part of
the positioning lead segment 510. Any conventional method, such as
stamping or etching, can be used to form the leads frame 505 out of
the sheet of metal 415. The lead frame 505 further comprises a one
or more non-positioning lead segments 520 and pad 525 configured to
accommodate an integrated circuit. Although not shown for the sake
of clarity, one of ordinary skill in the art would understand that
the lead frame 505 can also include other conventional components,
such as shorting bars, dam bars, etc. . . . , to facilitate forming
the integrated circuit package 400.
[0030] With continuing reference to FIGS. 4-5, FIG. 6 presents the
integrated circuit package 400 after coupling an integrated circuit
605 to the pad 525, coupling a heat sink 610 to the integrated
circuit 605, and coupling the positioning lead segments 510 and
non-positioning lead segments 520 to the integrated circuit 520.
Similar to that discussed above in the context of FIG. 1, both
direct coupling, or indirect coupling via bonding wires 615, are
within the scope of the invention.
[0031] With continuing reference to FIGS. 4-6, FIG. 7 show the
partially completed integrated circuit package 400 after removing
portions of the lead frame 505 to thereby form a plurality of leads
705 comprising positioning leads 710 having a stop 715 and
non-positioning leads 720. Any conventional device such as a
trimmer tool can be used to remove the undesired portions of the
lead frame. Each of the leads 705 has a first end 725 and a second
end 730, the first end 725 being coupled to the integrated circuit
605.
[0032] FIG. 7 also illustrates the partially completed integrated
circuit package 400 after enclosing the integrated circuit 605 in a
mold 740. For clarity, a transparent view through the mold 740 is
presented. Preferably, the mold 740 also encloses the first end 725
of the each of leads 705. As shown in FIG. 7, in some cases it is
advantageous for one or more of the positioning leads 710 to be
left attached to the lead frame 505 shown in FIG. 5, while the
non-positioning leads 715 are isolated from the lead frame 505. In
such instances, the positioning lead segment 510 and positioning
lead 710 are substantially the same structures. Of course, any
combination of leads 705 that are each attached or isolated from
the lead frame 505 is also within the scope of the present
invention.
[0033] With continuing reference to FIGS. 4-7, FIG. 8 shows the
completed integrated circuit package 400 after bending the leads
705, below the plane of view, and mounting the integrated circuit
package to a mounting board 805 having a plurality of mounting
holes 810. Any conventional device such as a bending tool can be
used to bend the leads 705. The leads 705 are bent below the plane
of view to configure the second ends of the leads 730 shown in FIG.
7 to pass through the mounting holes 810 and thereby extend the
second ends 730 through the mounting board 805. Preferably, the
positioning lead 710 is bent to configure the stop 715 to be below
a bottom surface of the mold 740. In some preferred embodiments,
the plurality of mounting holes 810 all have substantially a same
diameter 815, although embodiments with differently-sized mounting
holes are also within the scope of the present invention.
[0034] The stop 715 of the positioning leads 710 is configured to
have a lateral dimension 820 greater than the diameter 815 of a
first hole 825. The stop 715 thereby limits an extension of at
least one non-positioning lead 720 through a second hole 830 of the
mounting holes 810. Moreover, because the stop 715 is a continuous
part of the positioning lead 710, the stop 715 is less prone to
deform, break or shear off while the integrated circuit package is
being mounted or in use, as compared to a stop that is mechanically
attached or bonded to the positioning lead 710. Returning to FIG.
7, the stop 715 of the positioning lead 710 is also configured to
have a width 745 greater than a width 750 that of an adjacent
portion 755 of the positioning lead. The adjacent portion 755 is
configured to pass through the first hole 825 shown in FIG. 8.
[0035] For the embodiment presented in FIGS. 4-8, the properties of
the positioning lead 710 requires that the method include the
preparation of a layout pattern 405, shown in FIG. 4, to have a
special lead layout pattern 415 for the positioning lead to define
a stop. In other embodiments of the method, however, the layout
pattern does not have a special lead layout pattern.
[0036] Such an embodiment is illustrated in FIGS. 9-13, which
present plan views of selected steps for an alternative exemplary
method of manufacturing an integrated circuit package 900 according
to the present invention. Turning first to FIG. 9, illustrated is a
plan view of a partially completed integrated circuit package 900
after forming a layout pattern 905 on a metal sheet 910. The layout
pattern 905 comprises a lead layout pattern 915 for a plurality of
uniformly shaped leads. Unlike the embodiment presented in FIGS.
4-8, however, there is no special pattern for a positioning lead
having a stop.
[0037] With continuing reference to FIG. 9, as illustrated in FIG.
10, portions of the metal sheet 910 outside of the layout pattern
905 can be removed, using the same procedures as discussed in the
context of FIG. 5, to provide a lead frame 1005. The lead frame
1005 comprises lead segments 1010 that are uniformly shaped.
[0038] While maintaining reference to FIG. 9-10, FIG. 11 shows the
partially completed integrated circuit package 900 after adding an
integrated circuit 1105, heat sink 1110, and bonding wiring 1115 to
the integrated circuit package 900 using the same procedures as
discussed in the context of FIG. 6. Similarly, portions of the lead
frame 1005 can be removed to form a plurality of uniformly-shaped
leads 1120 having first and second ends 1125, 1130, and a mold 1140
applied to enclose the integrated circuit 1105, using the same
procedures discussed in the context of FIG. 7. As illustrated in
FIG. 11, however, all of the leads 1120 at this stage in the
manufacturing process are substantially identical and uniformly
shaped.
[0039] With continuing reference to FIG. 9-11, FIG. 12 shows the
partially completed integrated circuit package 900 after forming at
least one positioning lead 1210 by bending at least one of the
uniformly-shaped leads 1120 shown in FIG. 11 to form a stop 1215.
In this embodiment, the stop 1215 is a bend in the positioning lead
1210. Leads 1120 that are not bent in this fashion are
non-positioning leads 1220. As noted above, configuring the stop
1215 as a continuous part of the positioning lead 1210, makes the
stop 1215 resistant to deformation, breaking or shearing off while
the integrated circuit package 900 is being mounted or in use.
[0040] While still referring to FIG. 9-12, FIG. 13 shows the
integrated circuit package 900, after additional bending of the
positioning leads 1210, and for the first time, bending of the
non-positioning leads 1220, to situate their second ends 1130,
shown in FIG. 12, below the plane of view. The integrated circuit
package 900 is shown after coupling to a mounting board 1305,
having a plurality of holes 1310. Similar to previously discussed
embodiments, the stop 1215 of the positioning lead 1210 is
configured to have a lateral dimension 1315 that greater than a
diameter 1320 of a first hole 1325. The stop 1210 thereby limits an
extension of one or more non-positioning leads 1220 through a
second hole 1330.
[0041] For clarity, the manufacture of the integrated circuit
packages shown in FIGS. 4-8 and 9-13 are shown as separate process
flows. However, one skilled in the art would recognize that these
processes could be combined into a single process flow, if
desired.
[0042] Although the present invention has been described in detail,
those skilled in the art should understand that they could make
various changes, substitutions and alterations herein without
departing from the scope of the invention in its broadest form.
* * * * *