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What is claimed is:
1. A semiconductor apparatus comprising:
a printed circuit board having a plurality of bond pads each adapted to
receive a bond wire;
at least first and second semiconductor die each having a circuit side with
bond pads on said circuit side located at first and second ends of said
die, wherein said circuit side of each said die is attached to said
printed circuit board and said printed circuit board further comprises at
least one hole for each end of each said die; and
at least one bond wire for each said die, each said bond wire having first
and second ends, wherein said first end is attached to one of said bond
pads and said second end is attached to one of said printed circuit board
pads.
2. The apparatus of claim 1 further comprising a plurality of said die each
comprising a plurality of bond pads, wherein said bond pads on each of
said die are located at first and second ends of said die, and said
printed circuit board comprises at least one hole for each end of each of
said plurality of die.
3. The apparatus of claim 1 further comprising first, second, and third
printed circuit board surfaces wherein said second surface is in a plane
between a plane of said first surface and a plane of said third surface
and said die is attached to said second surface.
4. The apparatus of claim 1 further comprising first, second, third, and
fourth printed circuit board surfaces wherein said second and third
surfaces are interposed between said first and fourth surfaces and said
second surface is in a superior plane with respect to said third surface
and said printed circuit board pads are on said second surface and said
die is attached to said third surface.
5. A method of manufacturing a semiconductor module comprising the
following steps:
providing a printed circuit board having a first surface, a second surface
opposite said first surface, plurality of holes through said printed
circuit board, and a plurality of pads each adapted to receive a bond
wire;
providing a plurality of semiconductor die each having a circuit side with
a plurality of bond pads thereon at first and second ends of said die;
attaching said circuit side of each said die to said second surface of said
printed circuit board;
attaching bond wires to a plurality of said pads on said printed circuit
board and to a plurality of said bond pads, each said bond wire passing
through one of two holes associated with each said die.
6. The method of claim 5 wherein said printed circuit board further
comprises a third surface at a level between said first surface and said
second surface, wherein said printed circuit board pads are on said third
surface.
7. The method of claim 6 further comprising the step of sealing said bond
wires after said step of attaching said bond wires.
8. The method of claim 5 wherein said printed circuit board further
comprises a third surface at a level between said first surface and said
second surface, wherein said circuit side of each said die is attached to
said second surface.
9. The method of claim 5 wherein said printed circuit board further
comprises third and fourth surfaces each at a level between said first and
second surfaces, said third surface being in a superior plane with respect
to said fourth surface, wherein said printed circuit board pads are on
said third surface and said circuit side of each said die is attached to
said fourth surface.
10. The method of claim 9 further comprising the step of sealing said bond
wires after said step of attaching said bond wires.
11. A semiconductor apparatus comprising:
a printed circuit board having at least one hole therethrough and at least
two pads each adapted to receive a bond wire, said printed circuit board
further having first and second printed circuit board surfaces wherein
said first surface is in a superior plane with respect to said second
surface and said printed circuit board pads are on said second surface;
at least one semiconductor die having a circuit side with bond pads located
at first and second ends of said circuit side of said die, wherein said
circuit side of said die is attached to said printed circuit board;
at least two bond wires each having first and second ends, wherein said
first end of each bond wire is attached to one of said bond pads and said
second end is attached to one of said printed circuit board pads;
wherein said printed circuit board comprises at least one hole therein for
each end of each said at least one die.
12. The apparatus of claim 11 further comprising a plurality of said die
each comprising a plurality of bond pads, wherein said bond pads on each
of said die are centrally located on said die, and said printed circuit
board comprises at least one hole for each of said plurality of die.
13. The apparatus of claim 11 further comprising a plurality of said die
each comprising a plurality of bond pads, wherein said bond pads on each
of said die are located at first and second ends of said die, and said
printed circuit board comprises at least one hole for each end of each of
said plurality of die.
14. A semiconductor apparatus comprising:
a printed circuit board comprising first, second, third, and fourth printed
circuit board surfaces wherein said second and third surfaces are
interposed between said first and fourth surfaces and said second surface
is in a superior plane with respect to said third surface, said printed
circuit board further comprising at least one pad on said second surface
adapted to receive a bond wire and further having at least one hole
therethrough;
at least one semiconductor die having a circuit side with bond pads on said
circuit side, wherein said circuit side of said die is attached to said
third surface of said printed circuit board;
at least one bond wire having first and second ends, wherein said first end
is attached to one of said bond pads and said second end is attached to
said printed circuit board pad.
15. A method of manufacturing a semiconductor module, comprising the
following steps:
providing a printed circuit board having a first surface, a second surface
opposite said first surface, a third surface at a level between said first
and second surfaces, a plurality of holes through said printed circuit
board, and a plurality of pads on said third surface each adapted to
receive a bond wire;
providing a plurality of semiconductor die each having a circuit side with
a plurality of bond pads thereon;
attaching said circuit side of each said die to said second surface of said
printed circuit board;
attaching bond wires to a plurality of said pads of said printed circuit
board and to a plurality of said bond pads, each said bond wire passing
through one of said holes.
16. A method of manufacturing a semiconductor module comprising the
following steps:
providing a printed circuit board having a first surface, a second surface
opposite said first surface, a third surface at a level between said first
and second surfaces, a plurality of holes through said printed circuit
board, and a plurality of pads on said first surface each adapted to
receive a bond wire;
providing a plurality of semiconductor die each having a circuit side with
a plurality of bond pads thereon;
attaching said circuit side of each said die to said third surface of said
printed circuit board;
attaching bond wires to a plurality of said pads on said printed circuit
board and to a plurality of said bond pads, each said bond wire passing
through one of said holes. |
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Claims |
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Description |
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FIELD OF THE INVENTION
The invention relates to the field of semiconductor manufacture, and more
specifically to a method and apparatus for forming a particular
arrangement of a printed circuit board and a semiconductor die.
BACKGROUND OF THE INVENTION
Many types of semiconductor die such as dynamic random access memories
(DRAMs), static rams (SRAMs), programmable memories, logic devices, and
microprocessors are tested and packaged in a similar manner. After a
plurality of semiconductor die are manufactured from a wafer of
semiconductor material, a cursory test for functionality is performed on
each die. The die are singularized, and those die which passed the cursory
test are encapsulated in plastic or encased in a ceramic package.
Encapsulated packages comprise bond wires which electrically couple bond
pads on the die to a lead frame. The lead frame functions, in part, to
transfer an electric signal between the die and a printed circuit board
(PCB) to which leads of the lead frame are soldered.
After packaging, the die and package connections are rigorously tested
using strict electrical parameters under various environmental conditions.
Those which fail testing are scrapped.
The packaging of a semiconductor die has various problems associated
therewith. For example the packaging increases the size of the
semiconductor device which adds to space problems which are well known in
the art of computer and other electronic device manufacturing. Further,
packaging can contribute to overheating of the die which can cause the
packaged die to malfunction. Connections of the bond wire to the die and
to the lead frame, and the solder connections of the leads to the PCB, are
also common causes of device failure.
A semiconductor device which has fewer of the problems associated with
conventional device packaging would be desirable.
SUMMARY OF THE INVENTION
One embodiment of an inventive semiconductor apparatus comprises a printed
circuit board having at least one pad to receive a bond wire, and further
having at least one hole therethrough. A circuit side of a semiconductor
device having bond pads thereon is attached to the printed circuit board.
This embodiment of the inventive apparatus further comprises at least one
bond wire having first and second ends, wherein the first end is attached
to one of the bond pads and the second end is attached to the printed
circuit board pad.
Various objects and advantages will become apparent to those skilled in the
art from the following detailed description read in conjunction with the
appended claims and the drawings attached hereto.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top view of a first embodiment of an inventive semiconductor
apparatus, and FIG. 2 is a cross section of the FIG. 1 apparatus.
FIG. 3 is a top view of a second embodiment of the inventive semiconductor
apparatus, and FIG. 4 is a cross section of the FIG. 3 apparatus.
FIG. 5 is a cross section of another embodiment of the inventive
semiconductor apparatus.
FIG. 6 is a top view of another embodiment of the inventive apparatus, and
FIG. 7 is a cross section of the FIG. 6 embodiment.
FIGS. 8 and 9 are cross sections of two additional embodiments of the
inventive apparatus.
It should be emphasized that the drawings herein are not to scale but are
merely schematic representations and are not intended to portray the
specific parameters or the structural details of the invention, which can
be determined by one of skill in the art by examining the information
herein.
DETAILED DESCRIPTION OF THE INVENTION
One embodiment of an inventive semiconductor apparatus such as a memory
module is shown in FIG. 1 as a top view, and in FIG. 2 as a cross section
along "1" of FIG. 1. The semiconductor apparatus comprises a printed
circuit board (PCB) 10 having at least one pad 12, or more likely a
plurality of pads, adapted to receive a bond wire 14, and further having
at least one hole 16 therethrough. The apparatus further comprises at
least one semiconductor die 18, or more likely a plurality of die, each
having a circuit side with bond pads 20 on the circuit side. The circuit
side of the die is attached to the printed circuit board with an adhesive
(not shown). Adhesives such as thermoplastic, thermoset,
pressure-sensitive tape, or other adhesives known in the art would
function sufficiently.
Each bond wire 14 comprises first and second ends. The first end is
attached to one of the bond pads, and the second end is attached to one of
the printed circuit board pads. FIGS. 1 and 2 show each bond wire passing
through a single hole, although other arrangements are possible.
The die 18 can comprise a number of different configurations. Each die
shown in FIG. 1 comprises centrally located bond pads, and the PCB
comprises one hole for each die. The hole through the PCB allows access to
the centrally located bond pads on the die such that the bond wires can be
attached thereto.
FIG. 3, a top view, and FIG. 4, a cross section along "2" of FIG. 3, show
another embodiment of the invention which comprises at least one die, or
more likely a plurality of die, each comprising a plurality of bond pads
located at first and second ends of each die. The PCB comprises at least
one hole for each end of each die to provide access to the bond pads on
the die.
The bond wires can be connected in directions other than those shown in the
FIGS. While FIG. 3 shows the PCB pads toward the center of the PCB, they
could also be connected toward the edges of the PCB as shown in FIG. 5, or
a combination thereof similar to the arrangement shown in FIG. 6. In
addition, while FIGS. 3 and 4 show that the edge of the die is not
supported by the edge of the PCB, it may be advantageous to support the
edges of the die with the PCB as shown in FIG. 5 if the small dimensions
of the die allow. The distance between the edge of the bond pad and the
edge of the die is typically about 5 mils.
FIG. 7 shows another embodiment of the invention. In this embodiment the
PCB has first 70 and second 72 surfaces, with the first surface 70 in a
superior plane with respect to the second surface 72. In this embodiment,
the PCB pad 12 is on the second surface 72. Placing the bond wires in the
arrangement shown protects the bond wires from contact with other
conductive surfaces which might short the electrical connection, or with
other surfaces which could damage the bond wire or its connection with the
PCB pad or bond pad. Additionally, the bond wires can be sealed by filling
the hole with a layer of "glob top," encapsulant, or another workable
material which protects the bond wires, the die, and the PCB pads from
environmental damage, for example from moisture or from physical contact
with other surfaces. The protectant can be formed flush with the first
surface to provide a flat module.
FIG. 8 shows a cross section of another embodiment of the invention
comprising first 80, second 82, and third 84 printed circuit board
surfaces with the second surface 82 being in a plane between a plane of
the first surface 80 and a plane of said third surface 84. In this
embodiment, the die is attached to the second surface with an adhesive 86,
such as thermoplastic, thermoset, or pressure-sensitive double-sided tape.
If an adhesive is used which allows for removal of a die from the PCB
without damage to the PCB, a die which becomes nonfunctional can be more
easily replaced.
FIG. 9 shows another embodiment of the invention comprising first 90,
second 92, third 94 and fourth 96 PCB surfaces wherein the second 92 and
third 94 surfaces are interposed between the first 90 and fourth 96
surfaces, and wherein the second surface 92 is in a superior plane with
respect to the third surface 94. In this embodiment, the PCB pad 12 is on
the second surface 92 and the die 18 is attached to the third surface 94.
This embodiment provides for a flat assembly which may allow for the
placement of several assemblies in a small area, or for stacking several
modules.
In an inventive method for manufacturing an inventive semiconductor module,
a printed circuit board is provided. The PCB comprises a first surface, a
second surface opposite the first surface, a plurality of holes through
the PCB, and a plurality of pads on the first surface each adapted to
receive a bond wire. Further, a plurality of semiconductor die are
provided, each die having a circuit side with a plurality of bond pads
thereon. The circuit side of each die is attached to the second surface of
the PCB and bond wires are attached to a plurality of the pads on the
printed circuit board and to a plurality of the bond pads. In one
embodiment, each bond wire passes through one of the holes. The bond pads
on each of the die can be centrally located as described above, with each
bond wire attached to one of the die passing through a single hole. In
another embodiment, the bond pads on each of the die are located at first
and second ends of the die wherein each bond wire attached to one of the
die passes through one of two holes associated with the one die.
While this invention has been described with reference to illustrative
embodiments, this description is not meant to be construed in a limiting
sense. Various modifications of the illustrative embodiments, as well as
additional embodiments of the invention, will be apparent to persons
skilled in the art upon reference to this description. For example, while
the FIGS. generally show a single in-line memory module (SIMM), a wide
range of other boards, such as computer mother boards, other types of
memory modules, or PCBs with two or more types of die, such as a
microprocessor, logic devices, and memory can be assembled. Connections
other than bond wires could conceivably be used, and the number of holes
in the PCB may be more or less than the number shown in the FIGS. for each
type of die. It is therefore contemplated that the appended claims will
cover any such modifications or embodiments as fall within the true scope
of the invention.
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