U.S. patent application number 10/330054 was filed with the patent office on 2003-05-15 for semiconductor device.
Invention is credited to Kato, Shigenobu, Kitsukawa, Goro, Mishima, Michihiro, Noda, Kouichirou.
Application Number | 20030089926 10/330054 |
Document ID | / |
Family ID | 14993685 |
Filed Date | 2003-05-15 |
United States Patent
Application |
20030089926 |
Kind Code |
A1 |
Noda, Kouichirou ; et
al. |
May 15, 2003 |
Semiconductor device
Abstract
There is provided a large capacity memory such as a DRAM and an
SDRAM in which bonding pads PS and PD are not located at the
center, but are displaced from the center between memory array
regions UL and UR, disposed on the upper side of a four-bank
structure of banks 0 through 3, and memory array regions DL and DR,
disposed on the lower side thereof. Secondly, the disposition of
the bonding pads PS and PD is staggered on the right and left such
that the right half bonding pads PD are shifted up relative to the
left half bonding pads by about 30 .mu.m. Only a sense amplifier, a
column decoder and a main amplifier, which need to be near to the
memory array regions DL and DR, are disposed between the bonding
pads PS and PD, and the lower memory array regions DL and DR, and
further indirect peripheral circuits are disposed on the upper side
of the bonding pads PS and PD.
Inventors: |
Noda, Kouichirou;
(Fukuoka-shi, JP) ; Kato, Shigenobu; (Tokyo,
JP) ; Kitsukawa, Goro; (Tokyo, JP) ; Mishima,
Michihiro; (Tokyo, JP) |
Correspondence
Address: |
ANTONELLI TERRY STOUT AND KRAUS
SUITE 1800
1300 NORTH SEVENTEENTH STREET
ARLINGTON
VA
22209
|
Family ID: |
14993685 |
Appl. No.: |
10/330054 |
Filed: |
December 30, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10330054 |
Dec 30, 2002 |
|
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09310580 |
May 12, 1999 |
|
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Current U.S.
Class: |
257/203 ;
257/E27.081 |
Current CPC
Class: |
H01L 24/49 20130101;
H01L 27/105 20130101; H01L 2924/01027 20130101; H01L 27/0207
20130101; G11C 5/063 20130101; G11C 2207/105 20130101; G11C 5/025
20130101; H01L 2924/13091 20130101; H01L 2924/01005 20130101; G11C
5/14 20130101; H01L 2224/05554 20130101; H01L 2224/48247 20130101;
H01L 24/06 20130101; H01L 2224/04042 20130101; H01L 2224/45144
20130101; H01L 2924/01079 20130101; H01L 24/45 20130101; H01L
2224/49171 20130101; H01L 23/50 20130101; H01L 2224/06136 20130101;
H01L 2224/49113 20130101; G11C 11/4097 20130101; H01L 24/48
20130101; H01L 27/10897 20130101; H01L 2224/49175 20130101; H01L
2224/45144 20130101; H01L 2924/00014 20130101; H01L 2224/49171
20130101; H01L 2224/48247 20130101; H01L 2924/00 20130101; H01L
2224/49175 20130101; H01L 2224/48247 20130101; H01L 2924/00
20130101; H01L 2924/13091 20130101; H01L 2924/00 20130101 |
Class at
Publication: |
257/203 |
International
Class: |
H01L 027/10 |
Foreign Application Data
Date |
Code |
Application Number |
May 12, 1998 |
JP |
10-128797 |
Claims
What we claim is:
1. A semiconductor device, wherein memory array regions are
disposed in the peripheral part of a chip in the short edge
direction and a large number of bonding pads are disposed along the
long edge direction of said chip while putting aside to the upper
or lower side from the center of the center part of said chip in
the short edge direction; and said large number of bonding pads are
disposed such that the shift to the upper or lower side from the
center is different relatively at the left half portion and at the
right half portion centering on the center part of said chip in the
long edge direction.
2. The semiconductor device according to claim 1, wherein said
large number of bonding pads are disposed so as to be put aside to
the upper or lower side from the center of the center part of said
chip in the short edge direction and so that the shift to the upper
or lower side from the center is large in an address and clock
signal system and is small in a data signal system.
3. The semiconductor device according to claim 2, wherein an
electrostatic protecting element is disposed on one side of the
upper and lower sides of said bonding pad of said address and clock
signal system and output MOS transistors are disposed above and
below said bonding pad of the data signal system.
4. The semiconductor device according to claim 1, wherein said
semiconductor device is a DRAM or a synchronous DRAM of 64 M bits
or more.
5. A semiconductor device, having: a first edge extending in a
first direction; a second edge facing to said first edge; a third
edge extending in a second direction perpendicular to said first
edge; and a fourth edge facing to said third edge; said
semiconductor device further comprising: an output circuit; a first
memory array disposed between said first edge and a first imaginary
line; a second memory array disposed between said second edge and
said first imaginary line; and a plurality of pads being disposed
on a second imaginary line, wherein said first imaginary line is an
imaginary line connecting a middle point of said third edge and a
middle point of said fourth edge, wherein said second imaginary
line is an imaginary line which is parallel with said first
imaginary line and which is imaginarily disposed between said first
imaginary line and said second edge, wherein said plurality of pads
comprises a first pad; said output circuit being connected with
said first pad, wherein said output circuit comprises a first
transistor of a first conductive type and a second transistor of a
second conductive type, wherein said first conductive type is
different from said second conductive type, wherein said first
transistor is disposed between said second imaginary line and said
first memory array, and wherein said second transistor is disposed
between said second imaginary line and said second memory
array.
6. The semiconductor device according to claim 5, wherein said
first and second transistors are MOS transistors.
7. The semiconductor device according to claim 6, wherein said
first conductive type is P-type and said second conductive type is
N-type.
8. The semiconductor device according to claim 6, wherein said
output circuit comprises an inverter circuit having an output
terminal connected to said first pad and said inverter circuit
comprises said first and second transistors.
9. The semiconductor device according to claim 5, wherein said
first pad, said first transistor and said second transistor are
disposed on a third imaginary line and said third imaginary line
extends in the direction perpendicular to said first imaginary
line.
10. The semiconductor device according to claim 5, wherein said
first memory array and said second memory array contain a dynamic
type memory cells.
11. The semiconductor device according to claim 5, wherein said
first edge is longer than said third edge.
12. The semiconductor device according to claim 5, wherein the
centers of said plurality of pads are disposed on said second
imaginary line.
13. The semiconductor device according to claim 5, wherein each of
said plurality of pads is quadrilateral and a point where two
diagonal lines of said quadrilateral intersect is disposed on said
second imaginary line.
14. The semiconductor device according to claim 5, wherein the
centers of balance of said plurality of pads are disposed on said
second imaginary line.
15. A semiconductor device, having: a first edge extending in a
first direction; a second edge facing to said first edge; a third
edge extending in a second direction perpendicular to said first
edge; and a fourth edge facing to said third edge; said
semiconductor device further comprising: a plurality of first pads
to which data signals are supplied; a plurality of second pads to
which address signals are supplied; a first memory array disposed
between said first edge and a first imaginary line; and a second
memory array disposed between said second edge and said first
imaginary line, wherein said plurality of first pads are disposed
on a second imaginary line, wherein said plurality of second pads
are disposed on a third imaginary line, wherein said first
imaginary line is an imaginary line connecting a middle point of
said third edge and a middle point of said fourth edge, wherein
said second imaginary line is an imaginary line which is parallel
with said first imaginary line and which is imaginarily disposed
between said first imaginary line and said second edge, and wherein
said third imaginary line is an imaginary line which is parallel
with said first imaginary line and imaginarily disposed between
said second imaginary line and said second edge.
16. The semiconductor device according to claim 15, wherein said
plurality of first pads are disposed between a fourth imaginary
line and said third edge; said plurality of second pads are
disposed between said fourth imaginary line and said fourth edge;
and said fourth imaginary line is an imaginary line connecting the
middle point of said first edge and the middle point of said second
edge.
17. The semiconductor device according to claim 15, wherein said
first edge is longer than said third edge.
18. The semiconductor device according to claim 15, wherein the
centers of said plurality of second pads are disposed on said
second imaginary line; and the centers of said plurality of second
pads are disposed on said third imaginary line.
19. The semiconductor device according to claim 15, wherein each of
said plurality of first pads is quadrilateral and a point where two
diagonal lines of said quadrilateral intersect is disposed on said
second imaginary line; and each of said plurality of second pads is
quadrilateral and a point where two diagonal lines of said
quadrilateral intersect is disposed on said third imaginary
line.
20. The semiconductor device according to claim 15, wherein the
centers of balance of said plurality of first pads are disposed on
said second imaginary line; and the centers of balance of said
plurality of second pads are disposed on said third imaginary
line.
21. A semiconductor device, having: a first edge extending in a
first direction; a second edge facing to said first edge; a third
edge extending in a second direction perpendicular to said first
edge; and a fourth edge facing to said third edge; said
semiconductor device further comprising: a plurality of first pads;
a plurality of second pads; a first memory array disposed between
said first edge and a first imaginary line; and a second memory
array disposed between said second edge and said first imaginary
line, wherein said plurality of first pads are disposed on a second
imaginary line, wherein said plurality of second pads are disposed
on a third imaginary line, wherein said first imaginary line is an
imaginary line connecting a middle point of said third edge and a
middle point of said fourth edge, wherein said second imaginary
line is an imaginary line which is parallel with said first
imaginary line and which is imaginarily disposed between said first
imaginary line and said second edge, wherein said third imaginary
line is an imaginary line which is parallel with said first
imaginary line and imaginarily disposed between said second
imaginary line and said second edge, wherein no pad exists between
said plurality of first pads and said second edge, and wherein no
pad exists between said plurality of second pads and said first
edge.
22. The semiconductor device according to claim 21, wherein said
plurality of first pads are disposed between a fourth imaginary
line and said third edge; said plurality of second pads are
disposed between said fourth imaginary line and said fourth edge;
and said fourth imaginary line is an imaginary line connecting the
middle point of said first edge and the middle point of said second
edge.
23. The semiconductor device according to claim 22, wherein said
plurality of first pads receive data signals and said plurality of
second pads receive address signals.
24. The semiconductor device according to claim 21, wherein said
plurality of first pads receive data signals from the outside of
said semiconductor device and said plurality of second pads receive
address signals from the outside of said semiconductor device.
25. The semiconductor device according to claim 21, wherein said
first edge is longer than said third edge.
26. The semiconductor device according to claim 21, wherein the
centers of said plurality of second pads are disposed on said
second imaginary line and the centers of said plurality of second
pads are disposed on said third imaginary line.
27. The semiconductor device according to claim 21, wherein each of
said plurality of first pads is quadrilateral and a point where two
diagonal lines of said quadrilateral intersect is disposed on said
second imaginary line; and each of said plurality of second pads is
quadrilateral and a point where two diagonal lines of said
quadrilateral intersect is disposed on said third imaginary
line.
28. The semiconductor device according to claim 21, wherein the
centers of balance of said plurality of first pads are disposed on
said second imaginary line; and the centers of balance of said
plurality of second pads are disposed on said third imaginary line.
Description
[0001] This is a Continuation of U.S. application Ser. No.
09/310,580, filed May 12, 1999, the entire disclosure of which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a technology for laying out
semiconductor devices and more specifically to a technology
effectively applicable to the disposition of pads for efficiently
laying out a large capacity memory, such as a DRAM and a
synchronous DRAM (SDRAM).
[0003] The technological problem in DRAMs and SDRAMs which the
inventor has examined is that the number of bits tends to be
multiplied from x4 to xl6 and x32 and the number of pads tends to
be also increased. For instance, while the number of input/output
pins in a 64 M-bit DRAM (x4, x8 and xl6 have been realized by a
bonding option) is 54 in the package, the DRAM requires about 70
pads as internal pads, including normal signal pads, such as
address, clock and data signal pads, power source pads,
experimental pads and bonding option pads (for switching x4 through
xl6 and for switching the number of banks). It also requires
predetermined pad dimensions and spaces therebetween, and it has
become difficult to array the pads in a row for the LOC method
gradually in the shrink generation. Even if they can be arrayed in
a row, it has become difficult to assure large channel and power
source bus regions between them in their gap.
[0004] A step-down system or a voltage regulator is often adopted
in recent high-integrated memories, so that a variety of power
source lines are required within a chip.
[0005] They include VDD, VSS, VDDQ and VSSQ lines as the external
power source lines, and VPERI (for a peripheral circuit), VDL (for
a memory array), VPP (for a boost word driver) and VBB (for biasing
an array substrate) lines as the internal power source lines. Still
more, the power source lines may be divided into those for the
memory arrays (VDDA, VSSA), those for the general peripheral
circuits (VDD, VSS) and those for the input circuits (VDDI, VSSI)
as measures to counter noises. Thus, it has become difficult to
dispose the pads adequately due to the increase in the number of
the pads owing to the multiplication of bits and the variety of
power source lines which have come to be required due to the high
integration in memories, such as the DRAM and SDRAM.
[0006] It is noted that an example of the technology related to
large capacity memories, such as the DRAM and SDRAM, is described
in "Advanced Electronics I-9, Super LSI Memory" published by
Baifukan Co., Ltd. on Nov. 5, 1994.
[0007] Japanese Patent Laid-open No. 116865/1991 has disclosed a
semiconductor memory device in which direct peripheral circuits are
disposed in a region between two memory cell arrays along the
respective memory cell arrays, indirect peripheral circuits are
disposed in a region between the direct peripheral circuits along
one direct peripheral circuit, external terminals are disposed in
the region between the direct peripheral circuits along the other
direct peripheral circuit and a substrate voltage generating
circuit is disposed in a region between the indirect peripheral
circuit and the external terminal.
[0008] U.S. Pat. No. 5,579,256 (corresponding to Japanese Patent
Laid-Open No. 134568/1998) has disclosed a semiconductor device in
which bonding pads, a voltage converter, a substrate voltage
generating circuit and others are disposed at the center part of
the chip.
[0009] U.S. Pat. No. 5,473,198 (corresponding to Japanese Patent
Laid-open No. 350052/1994) has disclosed a semiconductor device in
which axially symmetrical data input/output pads are disposed in
two rows in parallel at the center part of the semiconductor
chip.
[0010] U.S. Pat. No. 5,640,362 (corresponding to Japanese Patent
Laid-open No. 128973/1997) has disclosed a synchronous
semiconductor memory device having a plurality of data input/output
pad groups 20 positioned at the right and left sides based on the
center of a semiconductor chip 100, disposed in a row horizontally
between upper and lower memory bank arrays 0 through 7 and having
the same number with the memory array banks 0 through 7 to
input/output information to/from the memory array banks 0 through
7.
[0011] U.S. Pat. No. 5,619,472 (corresponding to Japanese Patent
Laid-Open No. 139287/1996) has disclosed a center pad disposed type
semiconductor memory device in which an IO pad array, i.e., a first
pad array, is disposed between a core block 1 and a core block 2
and an address pad array, i.e., a second pad array, is disposed
between a core block 3 and a core block 4.
[0012] U.S. Pat. No. 5,627,792 (corresponding to Japanese Patent
Laid-Open No. 125143/1996) has disclosed a semiconductor memory
device in which respective pins (power source pins, ground pins,
data input/output pins, control system signal pins, address system
signal pins) of a lead frame are connected to bonding pad groups
disposed along a center line in the center part of a semiconductor
substrate by bonding wires 55.
SUMMARY OF THE INVENTION
[0013] In consideration of the regularity of the disposition of
standard pins in a large capacity memory, such as the DRAM and
SDRAM as described above, the inventor has examined an efficient
layout of the pads and the so-called indirect peripheral circuits
(except for the direct peripheral circuits, such as memory cells,
sense amplifiers and decoders) conforming to that. The subject
matter which the inventor has examined will be explained below with
reference to FIGS. 8 and 9.
[0014] The disposition of the standard pins of the DRAM and SDRAM
will be considered at first. FIG. 8 shows the disposition of the
pins of a 64 M SDRAM. As shown in the figure, data signal pins
(DQ*) exist at the upper half of the chip in the figure and address
and clock signal system pins (A*, CLK, CKE, /RAS, /CAS etc.) exist
at the lower half. This general arrangement is the same also in an
EDO DRAM other than the SDRAN. Considering this arrangement by
turning the chip clockwise through 90 degrees, it is seen from the
point of view of design of the chip that the data signal system
circuits exist at the right half of the chip and the address and
clock signal system circuits exist at the left half thereof. Thus,
concentrating on the characteristics of the bonding pad groups and
circuit groups whose properties are different, the inventor has
considered a way of disposing them efficiently.
[0015] FIG. 9 shows the disposition of the conventional LOC
assembling pads. The bonding pads PS and PD are disposed almost at
the center of the indirect peripheral circuit region, electrostatic
protecting elements and input/output circuits are disposed in the
vicinity of the bonding pads PS and PD and internal circuits such
as a control circuit and a pre-decoder are disposed between the
regions at both the upper and the lower sides of the bonding pads
PS and PD and the memory array regions UL, UR, DL and DR. Because
the internal circuit groups are divided vertically by the bonding
pads PS and PD in this arrangement, it becomes difficult to
exchange a large number of signals. Still more, there might be a
problem in that, when the circuit blocks are divided into upper and
lower parts, a power source line region is wasted because two sets
of power source bus lines are required.
[0016] It is an object of the present invention to provide a
semiconductor device in the form of a large capacity memory such as
a DRAM and SDRAM which allows an efficient layout of bonding pads
and indirect peripheral circuits to be realized by taking into
consideration the wiring and size of electrostatic protecting
elements and input/output circuits disposed in the vicinity of the
bonding pads and of the internal circuits disposed between the
upper and lower regions of the bonding pads and the memory array
regions.
[0017] The above and other objects as well as the novel
characteristics of the invention will be apparent from the
description provided in the present specification and from the
accompanying drawings.
[0018] The typical features of the invention disclosed in the
present application may be summarized as follows.
[0019] According to a first feature of the inventive semiconductor
device, bonding pad groups are not located at the center, but are
displaced to the upper or lower side of center between memory the
array regions in arranging the pads in a large capacity memory such
as a DRAM and an SDRAM having a large number of bonding pads.
Secondly, the disposition of the bonding pads is staggered on the
right and left, such that the right bonding pads on the data signal
side are disposed closer to the center more or less.
[0020] Because the indirect peripheral circuits are disposed
collectively on the other side in the semiconductor device
described above according to the first feature, it allows a number
of signals to be exchanged between the upper and lower sides by
causing the gap with the bonding pads to be reduced. It also
requires only one set of power source buses for the indirect
peripheral circuits.
[0021] The second feature allows a large number of signal channels
to be assured on the address and clock signal side. Although the
data signal side requires not so many signal channels as compared
to the address and clock signal side, large output transistors may
be suitably placed adjoining the bonding pad thereabove and
therebelow. While special power sources such as power sources
dedicated for the output transistors are necessary on the data
signal side additionally, they may be also suitably placed.
[0022] As a result, the indirect peripheral circuits may be laid
out efficiently on the chip as a whole and the improvement of the
speed may be achieved by the reduction of the chip area and the
shortening of the signal passages.
[0023] A semiconductor device of the invention has a first edge
(10-1) extending in a first direction; a second edge (10-2)
parallel to the first edge; a third edge (10-3) extending in a
second direction perpendicular to the first edge; and a fourth edge
(10-4) parallel to the third edge; and further comprises an output
circuit (22, 23); a first memory array (UR) disposed between the
first edge and a first imaginary line (10-5); and a second memory
array (DR) disposed between the second edge and the first imaginary
line. In the semiconductor device, the plurality of pads (PD) are
disposed on a second imaginary line (10-6); the first imaginary
line is an imaginary line connecting a middle point (10-8) of the
third edge and a middle point (10-9) of the fourth edge; and the
second imaginary line is an imaginary line which is parallel with
the first imaginary line and which is disposed between the first
imaginary line and the second edge. The plurality of pads contain a
first pad; the output circuit is connected with the first pad; the
output circuit contains a first transistor (22) of a first
conductivity type and a second transistor (23) of a second
conductivity type; the first conductivity type is different from
the second conductivity type; the first transistor is disposed
between the first imaginary line and the first memory array; and
the second transistor is disposed between the second imaginary line
and the second memory array.
[0024] The above configuration allows a layout area for disposing
the peripheral circuits to be largely prepared and an area occupied
by the output circuits to be reduced. For instance, when the first
and second transistors of the output circuit are PMOS and NMOS
transistors, at least a part of a separating region for separating
the PMOS and NMOS transistors may be created by utilizing the lower
part of the first pad connected to the output circuit. This then
allows the area occupied by the output circuits to be reduced.
[0025] Another semiconductor device of the invention has a first
edge extending in a first direction; a second edge parallel to the
first edge; a third edge extending in a second direction
perpendicular to the first edge; and a fourth edge parallel to the
third edge; and further comprises a plurality of first pads (PD) to
which data signals are supplied; a plurality of second pads-(PS) to
which address signals are supplied; a first memory array disposed
between the first edge and a first imaginary line; and a second
memory array disposed between the second edge and the first
imaginary line. In the semiconductor device, the plurality of first
pads are disposed on a second imaginary line; the plurality of
second pads are disposed on a third imaginary line (10-7); the
first imaginary line is an imaginary line connecting a middle point
of the third edge and a middle point of the fourth edge; the second
imaginary line is an imaginary line which is parallel with the
first imaginary line and which is disposed between the first
imaginary line and the second edge; and the third imaginary line is
an imaginary line which is parallel with the first imaginary line
and disposed between the second imaginary line and the second
edge.
[0026] The above configuration allows the space for disposing the
peripheral circuits such as an address buffer, an address decoder,
data input/output circuits for inputting/outputting data signals
and various voltage generating circuits to be prepared collectively
and an area occupied by the circuits for outputting the data
signals to be reduced. It also allows a large number of address
signal lines to be disposed collectively.
[0027] A still other semiconductor device of the invention has a
first edge extending in a first direction; a second edge parallel
to the first edge; a third edge extending in a second direction
perpendicular to the first edge; and a fourth edge parallel to the
third edge; and further comprises a plurality of first pads; a
plurality of second pads; a first memory array disposed between the
first edge and a first imaginary line; and a second memory array
disposed between the second edge and the first imaginary line. In
the semiconductor device, the plurality of first pads are disposed
on a second imaginary line; the plurality of second pads are
disposed on a third imaginary line; the first imaginary line is an
imaginary line connecting a middle point of the third edge and a
middle point of the fourth edge; the second imaginary line is an
imaginary line which is parallel with the first imaginary line and
which is disposed between the first imaginary line and the second
edge; the third imaginary line is an imaginary line which is
parallel with the first imaginary line and disposed between the
second imaginary line and the second edge; no pad exists between
the plurality of first pads and the second edge; and no pad exists
between the plurality of second pads and the first edge.
[0028] The above configuration allows the space for disposing the
peripheral circuits such as an address buffer and an address
decoder which receive address signals, data input/output circuits
for inputting/outputting data signals and various voltage
generating circuits to be prepared collectively and an area
occupied by the circuits for outputting the data signals to be
reduced. It also allows a large number of address signal lines to
be disposed collectively. Further, because no pad exists between
the plurality of first pads and the second edge and between the
plurality of second pads and the first edge, many circuits may be
disposed in this region and wires to be drawn around may be
reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIGS. 1(a) and 1(b) are a schematic layout diagram and a
partially enlarged view thereof, respectively, showing a
semiconductor memory device according to one embodiment of the
invention;
[0030] FIG. 2 is a schematic layout diagram showing the disposition
of bonding pads in the semiconductor memory device of the
embodiment;
[0031] FIG. 3 is a schematic layout diagram showing the disposition
of circuit blocks at the center part of a chip in the semiconductor
memory device of the embodiment;
[0032] FIG. 4 is a schematic layout diagram showing the disposition
of the bonding pads and power lines at the center part of the chip
in the semiconductor memory device of the embodiment;
[0033] FIG. 5 is a schematic circuit diagram showing the
surrounding area of the bonding pad for address and clock signals
in the semiconductor memory device of the embodiment;
[0034] FIG. 6 is a schematic circuit diagram showing the
surrounding area of the bonding pad for data signals in the
semiconductor memory device of the embodiment;
[0035] FIG. 7 is a schematic plan view showing an LOC bonding
arrangement in the semiconductor memory device of the
embodiment;
[0036] FIG. 8 is a diagram for explaining the disposition of
input/output pins in a semiconductor memory device which is a
precondition of the invention; and
[0037] FIG. 9 is a schematic layout showing the disposition of
bonding pads in the semiconductor memory device which is in
accordance with the precondition of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0038] An embodiment of the present invention will be explained in
detail based on the drawings. It is noted that the same reference
numerals denote the same members throughout the drawings for
explaining the embodiment and their repeated explanation will be
omitted.
[0039] The structural layout of the semiconductor memory device of
the present embodiment will be explained with reference to FIGS. 1a
and 1b at first.
[0040] The semiconductor memory device of the present embodiment is
formed as a large capacity memory, such as a DRAM or an SDRAM.
Formed on one semiconductor chip 10 by a known semiconductor
manufacturing technique are main row decoder regions 11, main word
driver regions 12, column decoder regions 13, peripheral circuit
and bonding pad regions 14, memory cell arrays 15, sense amplifier
regions 16, sub-word driver regions 17, and intersection regions
18. In FIG. 1, the horizontal direction is the line direction (word
line direction) and the vertical direction is the column direction
(bit line direction).
[0041] In the large capacity memory, memory array regions composed
of the memory cell arrays 15 and other elements are disposed, so as
to be divided into four banks 0 through 3 on the right and left
side in the line direction and on the upper and lower sides in the
column direction of the memory chip 10 as shown in FIG. 1 for
example. The memory array regions disposed on the right and left
sides each are disposed as a pair, while the main row decoder
region 11 is disposed at the center via the main word driver
regions 12.
[0042] The column decoder regions 13 corresponding to the memory
array regions disposed at the upper and lower sides of the memory
chip 10 are disposed at the center sides of the respective memory
array regions. Row address buffers, column address buffers,
pre-decoders, a timing generating circuit, data input/output
circuits and other elements are disposed and bonding pads for
connecting to the outside are provided further at the center
thereof as the peripheral circuit and bonding pad regions 14.
[0043] In the memory array region, the sense amplifier regions 16
are disposed in the column direction of the memory cell arrays 15
while adjoining the memory cell array, the sub-word driver regions
17 are disposed in the line direction thereof while adjoining them,
and an FX driver (for driving the sub-word driver) and a control
circuit of the sense amplifier group (such as a switching MOS
transistor) are disposed in the intersection region 18 of the sense
amplifier region 16 and the sub-word driver region 17. The word
line is set in the line direction and the bit line is set in the
column direction with respect to this memory cell array 15. It is
apparent that the invention is applicable also when this
disposition is reversed.
[0044] In the large capacity memory according to the invention, the
disposition of the bonding pads provided in the peripheral circuit
and bonding pad regions 14 at the center of the memory array
regions disposed at the upper and lower sides thereof is inventive.
This will be explained below with reference to FIGS. 2 through
7.
[0045] FIG. 2 is a diagram showing the disposition of the bonding
pads. In contrast to the one shown in FIG. 9, this arrangement has
two characteristic points. Firstly, the bonding pads PS and PD are
not disposed at the center, but are shifted off the centerline
between the memory array regions UL and UR disposed on the upper
side of the four banks of the banks 0 through 3 and the memory
array regions DL and DR disposed on the lower side. They are
shifted to the lower side in FIG. 2. Secondly, the disposition of
the bonding pads PS and PD are staggered on the right side relative
to the left side. That is, the right-half bonding pads PD are
shifted up relative to the bonding pads PS. The relative shift is
around 30 .mu.m. only the sense amplifier, the column decoder and
the main amplifier which need to be near to the memory array
regions DL and DR are disposed between the bonding pads PS and PD
and the lower memory array regions DL and DR and the so-called
indirect peripheral circuits are placed on the upper side of the
bonding pads PS and PD.
[0046] Because the indirect peripheral circuits are disposed
collectively on the upper side by shifting the bonding pads PS and
PD towards the lower side as a whole according to the first
characteristic point, the number of signals exchanged on the upper
and lower sides of the bonding pads PS and PD is reduced remarkably
as compared to the case of FIG. 9. Further, it is necessary to
provide only one set of power source buses which are necessary for
the indirect peripheral circuits on the
[0047] upper side. Although power sources for the column decoder
and the main amplifier are necessary also on the lower side as a
matter of course, they may be omitted because a large number of
power sources are unnecessary on the lower side.
[0048] A large number of signal channels accompanying the X and Y
address signal system and the control circuit may be assured in the
indirect peripheral circuits on the left side by relatively
disposing the right bonding pads PD toward the upper side more or
less. While the input/output circuits which handle data mostly
occupy the right side and require less signal channels as compared
to the left side, it is preferable to shift the bonding pads PD to
the upper side to place the large output transistors so as to be
adjoining above and below the bonding pads PD. Further, while
special power sources such as VDDQ and VSSQ dedicated to the output
transistors are necessary additionally on the right side, they may
be placed preferably.
[0049] For instance, as for the dimensions between the bonding pads
PS and PD and the memory array regions UL, UR, DL and DR, when the
interval T between the memory array regions UL and UR disposed on
the upper side and the memory array regions DL and DR disposed on
the lower side is around 700 .mu.m, the center line of the bonding
pads PS of the address and clock signal system on the left side is
disposed so as to be spaced by a distance TL of around 230 .mu.m
from the center and the center line of the bonding pads PD of the
data signal system is disposed so as to be spaced by a distance TR
of around 200 .mu.m from the center. No sense amplifier is included
in the region of T, even though the main amplifier and the column
decoder are included. The difference in shift between the bonding
pads PS and the bonding pads PD is around 30 .mu.m. The bonding
pads PS and bonding pads PD include voltage pads such as VDD and
VSS.
[0050] FIG. 3 is an enlarged view of the center part of the chip. A
well separation may be omitted and the positive side power source
line may be shared by placing two indirect peripheral circuit
groups so that PMOS transistors adjoin each other back to back.
When a metallic three-layer wiring structure is adopted, a metallic
first layer is used for connecting elements within the cell, and
the metallic second layer and the metallic third layer are used for
coupling signals and power sources in the vertical (short edge)
direction and the horizontal (long edge) direction, respectively,
in the long edge region between the upper and lower memory array
regions UL, UR, DL and DR. This is because the metallic three-layer
wiring structure is thick and has the lowest resistance. Because
the row decoder and main word driver regions between the memory
array regions UL and UR and the memory array regions DL and DR are
long in the vertical direction, the metallic three-layer wire is
arranged in the vertical direction.
[0051] FIG. 4 shows the power source lines at the center part of
the chip. A variety of power source lines are shown in the figure.
VDDQ and VSSQ are the power sources dedicated to the output
transistors, VSSI and VDDI are those for the input circuits, VDDA
and VSSA are those for driving the sense amplifiers, VPERI is a
step-down power source for the peripheral circuits, VDL is a power
source for memory cell storage voltage and VPP is a power source
for boosting the word line. Among these power source lines, the
metallic two-layer and the metallic three-layer lines are arranged
in the vertical and horizontal directions, respectively.
[0052] FIG. 5 shows the bonding pad PS for input signals. An
electrostatic protecting element 21 is disposed on the bonding pad
PS for the address and clock signals and the bonding pad PS is
connected to an internal circuit via the electrostatic protecting
element 21. The electrostatic protecting element 21 occupies a
large area on one side of the bonding pad PS. A broken line in the
figure indicates its approximate size.
[0053] FIG. 6 shows the bonding pad PD for data signals. An output
PMOS transistor 22 and an output NMOS transistor 23 are disposed
above and below the bonding pad PD. Gates of the output PMOS
transistor 22 and the output NMOS transistor 23 are connected to
the internal circuit. Broken lines in the figure indicate their
approximate size. In contrast to the bonding pad PS for the input
signals shown in FIG. 5, the bonding pad PD requires large areas
thereabove and therebelow.
[0054] When the bonding pads are to be disposed efficiently by
taking into account the differences in the sizes and the wiring
characteristics of the elements around the bonding pad PS in FIG. 5
and the bonding pad PD in FIG. 6, it is desirable to stagger the
position of the bonding pads PS and PD up and down on the right and
left sides thereof as shown in FIGS. 2, 3 and 4. Thus, the bonding
pads PS and PD on the right and left sides are located on the lower
side, and the right bonding pads PD are disposed so as to be closer
to the center more or less.
[0055] FIG. 7 is a plan view showing the state in which bonding has
been implemented on an LOC (lead on chip) package. In the LOC
package, a lead frame 31 is disposed above the memory chip 10 in
the figure and the bonding pads PS and PD of the memory chip 10 are
connected with the edge of the lead frame 31 by wire bonding using
wires 32, such as gold lines. The bonding may be implemented on the
LOC package in the same manner as the conventional method because
the bonding pads PS and PD deviate less from the whole memory chip
10 even if they are shifted. FIG. 7 shows a package corresponding
to the one shown in FIG. 8 in which the number of input/output pins
is 54.
[0056] Therefore, according to the semiconductor memory device of
the present embodiment, the indirect peripheral circuits are
disposed collectively on the upper side by shifting the bonding
pads PS and PD to the lower side as a whole, so that the number of
signals exchanged between the upper and lower sides by using the
gaps between the bonding pads PS and PD may be reduced. Further,
only one set of power source buses is necessary for the indirect
peripheral circuits. Still more, a large number of signal channels
may be assured on the address and clock signal side by locating the
right bonding pads PD closer to the upper side more or less.
Although the data signal side requires not so many signal channels
as compared to the address and clock signal side, the large output
PMOS transistor 22 and the output NMOS transistor 23 may be
suitably placed above and below the bonding pad PD while adjoining
it. The special power sources such as VDDQ and VSSQ dedicated for
the transistors 22 and 23 may be also suitably placed additionally.
As a result, the indirect peripheral circuits may be efficiently
laid out on the chip as a whole.
[0057] While the invention has been explained concretely based on
an embodiment thereof, it is needless to say that the invention is
not limited to the embodiment described above and may be variously
modified within the scope of the invention.
[0058] For instance, although the case of disposing the bonding
pads by shifting them to the lower side of center as a whole has
been explained in the embodiment described above, the invention is
not limited to such a case, since the bonding pads may be disposed
by shifting them to the upper side of center. It is preferable to
dispose the data signal side bonding pads so as to be closer to the
center more or less also in this case.
[0059] Further, although the case of the four bank structure in
which the memory array region is composed of the banks 0 through 3
has been shown, the invention is applicable also to a bank
structure of eight banks for example. In such a case, the same
effect may be obtained by disposing the bonding pads in the same
manner as described above.
[0060] The effects obtained from typical aspects of the invention
disclosed in the present application may be summarized as
follows:
[0061] Because the indirect peripheral circuits may be disposed
collectively on the other side by disposing the bonding pad groups
not at the center, but as shifted to the upper or lower side
between the memory array regions, the number of signals exchanged
between the upper and lower sides by using the gaps of the bonding
pads may be reduced;
[0062] (2) Only one set of power source buses necessary for the
indirect peripheral circuits needs to be provided when disposing
the indirect peripheral circuits collectively on the other side by
the effect (1) described above;
[0063] (3) A large number of signal channels may be assured on the
address and clock signal side by staggering the disposition of the
bonding pads on the right and left sides and by disposing the data
signal side bonding pads so as to be closer to the center more or
less;
[0064] (4) The large output transistors may be placed above and
below the bonding pad while adjoining it on the data signal side by
disposing the data signal side bonding pads so as to be closer to
the center by the effect (3) described above;
[0065] (5) The special power sources such as the power sources
dedicated for the output transistors may be disposed additionally
by disposing the data signal side bonding pads so as to be closer
to the center by the effect (3) described above; and
[0066] (6) Because the bonding pads and the indirect peripheral
circuits may be efficiently laid out in the large capacity memory
such as the DRAM and the SDRAM by the effects (1) through (5)
described above, the speed may be improved by the reduction of the
chip area and the reduction in length of the signal passages.
* * * * *