U.S. patent application number 09/956996 was filed with the patent office on 2002-02-07 for semiconductor integrated circuit.
This patent application is currently assigned to Hitachi, Ltd.. Invention is credited to Rikino, Kunihito, Sasaki, Yasuhiko, Yamashita, Shunzo, Yano, Kazuo.
Application Number | 20020014899 09/956996 |
Document ID | / |
Family ID | 23592771 |
Filed Date | 2002-02-07 |
United States Patent
Application |
20020014899 |
Kind Code |
A1 |
Sasaki, Yasuhiko ; et
al. |
February 7, 2002 |
Semiconductor integrated circuit
Abstract
The I/O terminal positions of a pass transistor logic circuit
cell are distributed in the cell, an output amplifier is provided
on the end part of the cell, the pass transistor circuit is
arranged in the direction in which a potential supply line extends,
a signal polarity inverting circuit is laid out in the cell and the
arrangement of wells is different from the arrangement of a
conventional CMOS logic circuit.
Inventors: |
Sasaki, Yasuhiko; (Koganei,
JP) ; Rikino, Kunihito; (Tachikawa, JP) ;
Yano, Kazuo; (Hino, JP) ; Yamashita, Shunzo;
(Tokorozawa, JP) |
Correspondence
Address: |
MATTINGLY, STANGER & MALUR, P.C.
1800 Diagonal Road, Suite 370
Alexandria
VA
22314
US
|
Assignee: |
Hitachi, Ltd.
|
Family ID: |
23592771 |
Appl. No.: |
09/956996 |
Filed: |
September 21, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09956996 |
Sep 21, 2001 |
|
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09402648 |
Feb 3, 2000 |
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6313665 |
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Current U.S.
Class: |
326/101 ;
257/E27.107 |
Current CPC
Class: |
H01L 27/0207 20130101;
H01L 27/11803 20130101; H01L 2924/00 20130101; H01L 2924/0002
20130101; H01L 2924/0002 20130101 |
Class at
Publication: |
326/101 |
International
Class: |
H01L 025/00; H03K
019/00 |
Claims
1. A semiconductor integrated circuit characterized in that in a
semiconductor integrated circuit having a cell comprising a logical
operation circuit including at least one pass transistor circuit
and at least one output signal amplifier: wherein the pass
transistor circuit in the logical operation circuit includes a
first input node, a second input node and a third input node, a
pass transistor output node, a first field effect transistor of a
first type or a second type, a source/drain path of which is
connected between the first input node and the pass transistor
output node and a second field effect transistor of the first type
or the second type, a source/drain path of which is connected
between the second input node and the output node; wherein the
output signal amplifier in the logical operation circuit includes a
circuit comprising an input node, an output node, a field effect
transistor of the first type, a drain/source path of which is
connected between the output node and first potential and a gate of
which responds to the input node of the output signal amplifier and
a field effect transistor of the second type, a drain/source path
of which is connected between the output node of the output signal
amplifier and second potential and a gate of which responds to the
input node; wherein the output node of the pass transistor circuit
is connected to the input of the output signal amplifier; wherein
the third input node of the pass transistor circuit is applied with
an input signal from outside of the cell; wherein at least two of
all of the first input node and the second input node of the pass
transistor circuit are applied with input signals from outside of
the cell; wherein the output node of the output signal amplifier
operates to output an output signal to outside of the cell; and
wherein when a coordinate system is determined in a direction of
running a supply line of the first potential and a supply line of
the second potential and a direction orthogonal thereto, respective
terminals by a conductor layer for drawing the input signals from
outside of the cell and the output signal to outside of the cell
are arranged to include terminal grid points disposed at constant
intervals in the coordinate system and grid coordinates of at least
one of the respective terminals differ from grid coordinates
arranged with at least two or more of the terminals other than the
at least one terminal.
2. A semiconductor integrated circuit characterized in that in a
semiconductor integrated circuit having a cell comprising a logical
operation circuit including at least one pass transistor circuit
and at least one output signal amplifier: wherein the pass
transistor circuit in the logical operation circuit includes a
first input node, a second input node and a third input node, an
output node, a first field effect transistor of a first type or a
second type, a source/drain path of which is connected between the
first input node and the output node and a second field effect
transistor of the first type or the second type, a source/drain
path of which is connected between the second input node and the
output node; wherein the output signal amplifier in the logical
operation circuit includes a circuit comprising an input node, an
output node, a field effect transistor of the first type, a
drain/source path of which is connected between the output node and
first potential and a gate of which responds to the input node anda
field effect transistor of the second type, a drain/source path of
which is connected between the output node and second potential and
a gate of which responds to the input node; wherein the output node
of the pass transistor circuit is connected to the input of the
output signal amplifier; wherein the third input node of the pass
transistor circuit is applied with an input signal from outside of
the cell; wherein at least two of all of the first input node and
the second input node of the pass transistor circuit are applied
with input signals from outside of the cell; wherein the output
node of the output signal amplifier operates to output an output
signal to outside of the cell; and wherein when a coordinate system
is determined in a direction of running a supply line of the first
potential and a supply line of the second potential and a direction
orthogonal thereto, a terminal from outside of the cell for
inputting an input signal applied to the third input node of the
pass transistor circuit is arranged to shift to a larger side or a
smaller side of the coordinate system rather than terminals from
outside of the cell for inputting input signals applied to the
first input node and the second input node of the pass transistor
circuit.
3. A semiconductor integrated circuit characterized in that in a
semiconductor integrated circuit having a cell comprising a logical
operation circuit including at least one pass transistor circuit
and at least one output signal amplifier: wherein the pass
transistor circuit in the logical operation circuit includes a
first input node, a second input node and a third input node, an
output node, a first field effect transistor of a first type or a
second type, a source/drain path of which is connected between the
first input node and the output node and a second field effect
transistor of the first type or the second type, a source/drain
path of which is connected between the second input node and the
output node; wherein the output signal amplifier in the logical
operation circuit includes a circuit comprising an input node, an
output node, a field effect transistor of the first type, a
drain/source path of which is connected between the output node and
first potential and a gate of which responds to the input node and
a field effect transistor of the second type, a drain/source path
of which is connected between the output node and second potential
and a gate of which responds to the input node; wherein the output
node of the pass transistor circuit is connected to the input of
the output signal amplifier; and wherein when a coordinate system
is determined in a direction of running a supply line of the first
potential and a supply line of the second potential, the two types
of the field effect transistors constituting the output signal
amplifier are arranged to at least one of a cell boundary on a side
having smallest coordinate values or a cell boundary on a side
having largest coordinate values.
4. A semiconductor integrated circuit characterized in that in a
semiconductor integrated circuit having a cell comprising a logical
operation circuit including at least one pass transistor circuit
and at least one output signal amplifier: wherein the pass
transistor circuit in the logical operation circuit includes a
first input node, a second input node and a third input node, an
output node, a first field effect transistor of a first type or a
second type, a source/drain path of which is connected between the
first input node and the output node and a second field effect
transistor of the first type or the second type, a source/drain
path of which is connected between the second input node and the
output node; wherein the output signal amplifier in the logical
operation circuit includes a circuit comprising an input node, an
output node, a field effect transistor of the first type, a
drain/source path of which is connected between the output node and
first potential and a gate of which responds to the input node and
a field effect transistor of the second type, a drain/source path
of which is connected between the output node and second potential
and a gate of which responds to the input node; wherein the output
node of the pass transistor circuit is connected to the input of
the output signal amplifier; wherein the third input node of the
pass transistor circuit is applied with an input signal from
outside of the cell; wherein at least two of all of the first input
node and the second input node of the pass transistor circuit are
applied with input signals from outside of the cell; wherein the
output node of the output signal amplifier operates to output an
output signal to outside of the cell; and wherein a plurality of
the pass transistor circuits are provided in the cell and the pass
transistor circuits are developed to arrange in a direction of
running a supply line of the first potential and a supply line of
the second potential.
5. A semiconductor integrated circuit characterized in that in a
semiconductor integrated circuit having a cell comprising a logical
operation circuit including at least one pass transistor circuit
and at least one output signal amplifier: wherein the pass
transistor circuit in the logical operation circuit includes a
first input node, a second input node and a third input node, an
output node, a first field effect transistor of a first type or a
second type, a source/drain path of which is connected between the
first input node and the output node and a second field effect
transistor of the first type or the second type, a source/drain
path of which is connected between the second input node and the
output node; wherein the output signal amplifier in the logical
operation circuit includes a circuit comprising an input node, an
output node, a field effect transistor of the first type, a
drain/source path of which is connected between the output node and
first potential and a gate of which responds to the input node and
a field effect transistor of the second type, a drain/source path
of which is connected between the output node and second potential
and a gate of which responds to the input node; wherein the output
node of the pass transistor circuit is connected to the input of
the output signal amplifier; wherein the third input node of the
pass transistor circuit is applied with an input signal from
outside of the cell; wherein at least two of all of the first input
node and the second input node of the pass transistor circuit are
applied with input signals from outside of the cell; wherein the
output node of the output signal amplifier operates to output an
output signal to outside of the cell; and wherein a plurality of
the pass transistor circuits are present at inside of the cell and
a width of a source/drain region of the field effect transistor
constituting the pass transistor circuit in a direction of running
a supply line of the first potential and a supply line of the
second potential is changed depending on locations in the same
source/drain region.
6. A semiconductor integrated circuit characterized in that in a
semiconductor integrated circuit having a cell comprising a pass
transistor logical operation circuit including at least one pass
transistor circuit and at least one output signal amplifier:
wherein the pass transistor circuit in the pass transistor logical
operation circuit includes a first input node, a second input node
and a third input node, an output node, a first field effect
transistor of a first type or a second type, a source/drain path of
which is connected between the first input node and the output node
and a second field effect transistor of the first type or the
second type, a source/drain path of which is connected between the
second input node and the output node; wherein the output signal
amplifier in the logical operation circuit includes a circuit
comprising an input node, an output node, a field effect transistor
of the first type, a drain/source path of which is connected
between the output node and first potential and a gate of which
responds to the input node and a field effect transistor of the
second type, a drain/source path of which is connected between the
output node and second potential and a gate of which responds to
the input node; wherein the output node of the pass transistor
circuit is connected to the input of the output signal amplifier;
and wherein assuming that the cell is arranged contiguous to a CMOS
logical operation circuit cell constituting a logic by connecting a
field effect transistor of the first type and a field effect
transistor of the second type in a complementary relationship, a
boundary between a semiconductor region of the second type
surrounding the field effect transistor of the first type
constituting the CMOS logical operation circuit and a semiconductor
region of the first type surrounding the field effect transistor of
the second type and a boundary between a semiconductor region of
the second type surrounding the field effect transistor of the
first type constituting the pass transistor logical operation
circuit and a semiconductor region of the first type surrounding
the field effect transistor of the second type, are realized to
connect linearly at a portion connecting thereof.
7. A semiconductor integrated circuit characterized in that in a
semiconductor integrated circuit having a cell comprising a pass
transistor logical operation circuit including at least one pass
transistor circuit and at least one output signal amplifier:
wherein the pass transistor circuit in the pass transistor logical
operation circuit includes a first input node, a second input node
and a third input node, an output node, a first field effect
transistor of a first type or a second type, a source/drain path of
which is connected between the first input node and the output node
and a second field effect transistor of the first type or the
second type, a source/drain path of which is connected between the
second input node and the output node; wherein the output signal
amplifier in the logical operation circuit includes a circuit
comprising an input node, an output node, a field effect transistor
of the first type, a drain/source path of which is connected
between the output node and first potential and a gate of which
responds to the input node and a field effect transistor of the
second type, a drain/source path of which is connected between the
output node and second potential and a gate of which responds to
the input node; wherein the output node of the pass transistor
circuit is connected to the input of the output signal amplifier;
and wherein assuming that the cell is arranged contiguous to a CMOS
logical operation circuit cell constituting a logic by connecting a
field effect transistor of the first type and a field effect
transistor of the second type in a complementary relationship, a
boundary between a semiconductor region of the second type
surrounding the field effect transistor of the first type
constituting the pass transistor logical operation circuit and a
semiconductor region of the first type surrounding the field effect
transistor of the second type, is brought to a side of the first
semiconductor or a side of the second semiconductor and arranged to
be nonlinear at inside of the cell.
8. A semiconductor integrated circuit characterized in that in a
semiconductor integrated circuit including a cell comprising a pass
transistor logical operation circuit having a pair of at least one
set of pass transistor circuits and signal polarity inverting
circuits and at least one output signal amplifier: wherein the pass
transistor circuit in the logical operation circuit includes a
first input node, a second input node and a third input node, an
output node, a field effect transistor of a first type or a second
type, a source/drain path of which is connected between the first
input node and the output node and a field effect transistor of the
first type or the second type, a source/drain path of which is
connected between the second input node and the output node;
wherein the signal polarity inverting circuit in the logical
operation circuit includes a circuit comprising an input node, an
output node, a field effect transistor of the first type, a
drain/source path of which is connected between the output node and
first potential and a gate of which responds to the input node and
a field effect transistor of the second type, a drain/source path
of which is connected between the output node and second potential
and a gate of which responds to the input node; wherein the output
signal amplifier in the logical operation circuit includes a
circuit comprising an input node, an output node, a field effect
transistor of the first type, a drain/source path of which is
connected between the output node and the first potential and a
gate of which responds to the input node and a field effect
transistor of the second type, a drain/source path of which is
connected between the output node and the second potential and a
gate of which responds to the input node; and wherein the output
node of the pass transistor circuit is connected to the input of
the output signal amplifier.
9. A semiconductor integrated circuit characterized in that in a
semiconductor integrated circuit including a cell comprising a pass
transistor logical operation circuit having a pair of at least one
set of pass transistor circuits and signal polarity inverting
circuits and at least one output signal amplifier: wherein the pass
transistor circuit in the logical operation circuit includes a
first input node, a second input node and a third input node, an
output node, a field effect transistor of a first type or a second
type, a source/drain path of which is connected between the first
input node and the output node and a field effect transistor of the
first type or the second type, a source/drain path of which is
connected between the second input node and the output node;
wherein the signal polarity inverting circuit in the logical
operation circuit includes a circuit comprising an input node, an
output node, a field effect transistor of the first type, a
drain/source path of which is connected between the output node and
first potential and a gate of which responds to the input node and
a field effect transistor of a second type, a drain/source path of
which is connected between the output node and second potential and
a gate of which responds to the input node; wherein the output
signal amplifier in the logical operation circuit includes a
circuit comprising an input node, an output node, a field effect
transistor of the first type, a drain/source path of which is
connected between the output node and the first potential and a
gate of which responds to the input node and a field effect
transistor of the second type, a drain/source path of which is
connected between the output node and the second potential and a
gate of which responds to the input node; wherein the output node
of the pass transistor circuit is connected to the input of the
output signal amplifier; wherein the field effect transistor of the
first type constituting the output signal amplifier is provided
with a gate width larger than a gate width of the field effect
transistor of the first type constituting the signal polarity
inverting circuit; and wherein the field effect transistor of the
second type constituting the output signal amplifier is provided
with a gate width larger than a gate width of the field effect
transistor of the second type constituting the signal polarity
inverting circuit.
10. A semiconductor integrated circuit characterized in that in a
semiconductor integrated circuit including a cell comprising a pass
transistor logical operation circuit having a pair of at least one
set of pass transistor circuits and signal polarity inverting
circuits and at least one output signal amplifier: wherein the pass
transistor circuit in the logical operation circuit includes a
first input node, a second input node and a third input node, an
output node, a field effect transistor of a first type or a second
type, a source/drain path of which is connected between the first
input node and the output node and a field effect transistor of the
first type or the second type, a source/drain path of which is
connected between the second input node and the output node;
wherein the signal polarity inverting circuit in the logical
operation circuit includes a circuit comprising an input node, an
output node, a field effect transistor of the first type, a
drain/source path of which is connected between the output node and
first potential and a gate of which responds to the input node and
a field effect transistor of a second type, a drain/source path of
which is connected between the output node and second potential and
a gate of which responds to the input node; wherein the output
signal amplifier in the logical operation circuit includes a
circuit comprising an input node, an output node, a field effect
transistor of the first type, a drain/source path of which is
connected between the output node and the first potential and a
gate of which responds to the input node and a field effect
transistor of the second type, a drain/source path of which is
connected between the output node and the second potential and a
gate of which responds to the input node; wherein the output node
of the pass transistor circuit is connected to the input of the
output signal amplifier; wherein the field effect transistor
constituting the pass transistor circuit is arranged between the
first type and the second type of the field effect transistors
constituting the signal polarity inverting circuit in respect of a
direction orthogonal to a direction of running a supply line of the
first potential and a supply line of the second potential.
11. A semiconductor integrated circuit characterized in that in a
semiconductor integrated circuit having a cell comprising a logical
operation circuit including at least one pass transistor circuit
and at least one output signal amplifier: wherein the pass
transistor circuit in the logical operation circuit includes a
first input node, a second input node and a third input node, an
output node, a first field effect transistor of a first type or a
second type, a source/drain path of which is connected between the
first input node and the output node and a second field effect
transistor of the first type or the second type, a source/drain
path of which is connected between the second input node and the
output node; wherein the output signal amplifier in the logical
operation circuit includes a circuit comprising an input node, an
output node, a first field effect transistor of a first type, a
drain/source path of which is connected between the output node and
first potential and a gate of which responds to the input node, a
second field effect transistor of a second type, a drain/source
path of which is connected between the output node and second
potential and a gate of which responds to the input node and a
third field effect transistor of the first type, a drain/source
path of which is connected between the input node and the first
potential and a gate of which responds to the output node; and
wherein in the output signal amplifier, wire connection from a
drain of the third field effect transistor to the gates of the
first field effect transistor and the second field effect
transistor is realized by passing the wire connection below a
supply line of the first potential by using a material for a gate
terminal of the transistor.
12. A semiconductor integrated circuit characterized in a
semiconductor integrated circuit including a plurality of cells, at
least one of said plurality of cells comprising: a plurality of
pass transistor circuits each including a first input node, a
second input node and a third input node, an output node, a field
effect transistor, a source/drain path is connected between the
first input node and the output node and a field effect transistor,
a source/drain path of which is connected between the second input
node and the output node; and an output signal amplifier including
a circuit comprising an input node, an output node, a field effect
transistor of a first type, a drain/source path of which is
connected between the output node and first potential and a gate of
which responds to the input node and a field effect transistor of a
second type, a drain/source path is connected between the output
node and second potential and a gate of which responds to the input
node; wherein the output node of the pass transistor circuit is
connected to the input node of the output signal amplifier; wherein
any of the input nodes of the pass transistor circuit is supplied
with an input signal from outside of the cell via an inverter
arranged at inside of the cell; and wherein the output node of the
output signal amplifier operates to output an output signal to
outside of the cell.
13. A semiconductor integrated circuit apparatus including a
plurality of cells having shapes surrounded by a plurality of
sides, wherein a first cell of the cells includes a well of a first
type and a well of a second type and a boundary line between the
well of the first type and the well of the second type is provided
with a first portion in parallel with a first one of the sides and
a second portion not in parallel therewith.
14. The semiconductor integrated circuit apparatus according to
claim 13, wherein the first portion of the boundary between the
wells intersects with a second and a third side intersecting with
the first side.
15. The semiconductor integrated circuit apparatus according to
either of claims 12 and 13, characterized in that a second cell of
the cells includes the well of the first type and the well of the
second type and a boundary line between the well of the first type
and the well of the second type is in parallel with the first side
of the cell.
16. The semiconductor integrated circuit apparatus according to
claim 15, wherein the first cell and the second cell are contiguous
to each other and at a contiguous portion, the boundary line
between the well of the first type and the well of the second type
of the first cell coincide with a boundary line between the well of
the first type and the well of the second type of the second
cell.
17. The semiconductor integrated circuit apparatus according to any
one of claims 13 through 15, wherein the first cell includes an
inverter receiving an input signal, a pass transistor receiving an
output from the inverter and an amplifying circuit receiving an
output from the pass transistor.
18. The integrated circuit apparatus according to any one of claims
13 through 15, wherein the first cell includes an inverter of a
first CMOS constitution, a transistor constituted by NMOS or pMOS
inputting an output from the inverter and an inverter having a
second CMOS constitution inputting an output from the
transistor.
19. The integrated circuit apparatus according to any one of claims
13 through 15, wherein the first cell includes a first circuit
receiving an input from outside of the cell, a transistor
constituted by nMOS or pMOS inputting an output from the first
circuit and a second circuit inputting an output from the
transistor wherein an output from the second circuit constitutes an
output to outside of the cell and a gain of the second circuit is
larger than a gain of the first circuit.
20. The integrated circuit apparatus according to nay one of claims
13 through 15, wherein the first cell includes an inverter
receiving an input, a transistor constituted by either one of NMOS
or pMOS inputting the input and an output from the inverter and an
amplifying circuit for inputting an output from the transistor
wherein an output from the amplifying circuit constitutes an output
to outside of the cell.
21. The semiconductor integrated circuit apparatus according to any
of claims 13 through 20, wherein in the first cell, input and
output terminals are arranged not to align on a straight line.
22. The semiconductor integrated circuit apparatus according to
claim 15, wherein in the second cell, input and output terminals
are arranged to align on a straight line.
23. The semiconductor integrated circuit apparatus according to
claim 22, wherein the second cell includes a logical gate
constituted by a CMOS transistor.
24. An integrated circuit apparatus, wherein in a semiconductor
integrated circuit apparatus including a plurality of cells having
a rectangular shape, at least one of the cells includes an input
terminal, an inverter of a CMOS constitution inputting an output
from the input terminal as a gate input, a transistor constituted
by nMOS or PMOS inputting an output from the inverter as a gate
input, an amplifying circuit of a CMOS constitution inputting an
output from the transistor as a gate input and an output terminal
outputting an output from the amplifying circuit to outside of the
cell.
25. The integrated circuit apparatus according to claim 24, wherein
a first potential supply line is provided along a first line of the
cell, a second potential supply line is provided along a second
side opposed to the first side, a pMOS transistor and an nMOS
transistor constituting the amplifying circuit are arranged on cell
inner sides of the first and the second potential supply lines and
the transistor is arranged between the pMOS transistor and the NMOS
transistor constituting the amplifying circuit.
26. The integrated circuit apparatus according to either of claims
24 and 25, wherein the first potential supply line is provided
along the first side of the cell, the second potential supply line
is provided along the second side opposed to the first side, the
pMOS transistor and the NMOS transistor constituting the inverter
are arranged on the cell inner sides of the first and the second
potential supply lines and the transistor is arranged between a
PMOS transistor and an nMOS transistor constituting the
inverter.
27. The integrated circuit apparatus according to either of claim
25 or 26, wherein gate electrode wirings of the pMOS transistor and
the NMOS transistor of the amplifying circuit having the CMOS
constitution are arranged along a third side orthogonal to the
first side and the second side.
28. The integrated circuit apparatus according to claim 27, when
there are a plurality of the transistors constituted by nMOS or
pMOS, the transistors are arranged from a side of a fourth side
opposed to the third side to the third side and when an output from
a first transistor among the plurality of transistors constitutes
an input of a second transistor, the first transistor is disposed
proximate to the fourth side and the second transistor is disposed
proximate to the third side.
29. The integrated circuit apparatus according to any one of claims
24 through 28, wherein a source potential of the transistor
constituting the amplifying circuit and a source potential of the
transistor constituting the inverter are made common.
Description
TECHNICAL FIELD
[0001] The present invention relates to a semiconductor integrated
circuit, particularly to a semiconductor integrated circuit
applicable to LSI for a general use processor, a signal processing
processor, an image processing processor or the like partially
including logical operation circuits.
BACKGROUND OF THE INVENTION
[0002] Conventionally, in realizing a large scale logical operation
circuit, there has widely been used systems of gate array, standard
cell (or cell base integrated circuit) and the like. In these
integrated circuits, a partial circuit referred to as cell is
prepared previously. A cell signifies a small scale logical
operation circuit in which layout of a mask pattern has been
completed, normally, a plurality of them are arranged on the same
chip. In respect of a cell, normally, other than mask layout,
positions and areas of input and output terminals, an operational
speed, power consumption and the like are prepared. A cell library
stores information with regard to the cell in a storage device for
assisting design of an integrated circuit. There has been known a
design system using such cells, which is combined with a circuit
referred to as a pass transistor circuit.
[0003] Pass transistor circuits have been introduced as
"Differential Pass-transistor Logic" in IEEE Journal of Solid-State
Circuits, Vol. sc-22, No. 2, April 1987 pp216-pp222 (hereinafter,
referred to as a first conventional technology) and as
"Complementary Pass-transistor Logic" in IEEE Journal of
Solid-State Circuits, Vol. sc-25, No. 2, April 1990 pp388-pp395
(hereinafter, referred to as a second conventional technology).
[0004] Further there has been shown a circuit design method in
which a pass transistor circuit is combined with a standard cell
system, mentioned above, in Custom Integrated Circuits Conference
1994 Digest pp603-pp606 (hereinafter, referred to as a third
conventional technology).
[0005] Further, there has also been introduced a design method in
which a pass transistor circuit is combined with the standard cell
system by utilizing a logical expressing method referred to as
"Binary Decision Diagram" in Proceedings of the 1994 IEICE fall
conference (basic and boundary region) of the Institute of
Electronics, Information and Communication Engineers (IEICE), pp64
(hereinafter, referred to as a fourth conventional technology).
[0006] Further, there has been shown a logical operation circuit
cell using a pass transistor circuit in Japanese Patent Laid-Open
No. 130856/1995 (hereinafter, referred to as a fifth conventional
technology).
DISCLOSURE OF THE INVENTION
[0007] FIG. 10 and FIG. 11 illustrate plane views (a) for
explaining layout of cells of conventional CMOS logical operation
circuits and circuit diagrams thereof (b). Notations p1001 through
p1003, n1001 through n1003, p110 through p1103 and n1101 through
n1103 designate transistors. According to the layout of a cell of a
CMOS logical operation circuit which has widely been used in a
conventional gate array or standard cell system shown by FIG. 10 or
FIG. 11, it is general to regularly arrange on a straight line
input and output terminals In1001 through In1003 and In1101 through
In1103 for outputting a signal to outside of the cell. This is
because in the case of a CMOS logical operation circuit, a portion
of a gate can be enlarged on an insulating film (not formed with
transistor) present between a first type of a field effect
transistor (for example, P-channel MOS) and a second type of a
field effect transistor (for example, N-channel MOS) which are in a
complementary relationship and accordingly, input and output
terminals (In1001, In1002, In1003 and Out10 in FIG. 10, In1101,
In102, In1103 and Out11 in FIG. 11) can easily be enlarged
therefrom by a conductor layer.
[0008] In the meantime, a pass transistor logical operation circuit
cell is constituted by one set or more of pairs of two pass
transistors, a gate of each of which responds to a complementary
signal and an output signal amplifier. It is a significant feature
of a pass transistor logical operation circuit cell that a logical
circuit portion and an amplifying circuit portion are separated in
this way. In cell layout of such a pass transistor circuit, when
input and output terminals are arranged on a straight line similar
to a cell of the conventional CMOS logical operation circuit, there
poses a problem in which an area efficiency is deteriorated by a
restriction of a design rule concerning a conductor layer.
Accordingly, in a pass transistor logical operation circuit cell,
it is not well known how these input and output terminals are to be
arranged.
[0009] Further, in laying out a pass transistor logical operation
circuit having the above-described constitution, it has not been
well known with regard to a problem of how to arrange the output
signal amplifier and the pairs of pass transistors.
[0010] Further, in the case of laying out a pass transistor logical
operation circuit cell having the above-described constitution and
a CMOS logical operation circuit cell on the same chip, it has not
been well known with regard to how to arrange a semiconductor
region surrounding each transistor and having a type reverse to a
type of the transistor (for example, n well in the case of pMOS
transistor) in the cell.
[0011] Further, it has not been well known with regard to at which
portion in a layout inside of a cell as well as outside of a cell,
a circuit for generating complementary signals provided to
respective gates in a pair of two pass transistors in the
above-described pass transistor logical operation circuit cell, is
to be arranged.
[0012] Further, in laying out field effect transistors constituting
respectives of a signal polarity inverting circuit for forming
complementary signals provided to respective gates of a pair of two
pass transistors of the above-described pass transistor logical
operation circuit and the above-described output signal amplifier,
it has not been well known with regard to at which positions and in
what magnitude relationship they are to be laid out.
[0013] Therefore, it is an object of the present invention with
regard to a cell using a pass transistor circuit, to provide a
semiconductor integrated circuit having a layout arrangement of
input and output terminals, an output signal amplifier, pairs of
pass transistors, well regions and a complementary signal
generating circuit capable of reducing an area, reducing a delay
time period and facilitating wirings outside of the cell.
[0014] In order to achieve the above-described object, a
semiconductor integrated circuit according to the present invention
is laid out under the following thought.
[0015] According to the present invention, there is used a cell
having a portion constituted by at least one pass transistor
circuit for forming a logic and at least one output signal
amplifier. In this case, as a typical example of the present
invention, an explanation will be given of a pass transistor
logical operation circuit cell in the case in which three of pass
transistor circuits are present in respect of a single output
signal amplifier. As will be shown later in an embodiment of FIG. 1
through FIG. 3, each pass transistor circuit includes a first input
node, a second input node and a third input node, an output node, a
field effect transistor of a first type or a second type, a
source/drain path of which is connected between the first input
node and the output node and a field effect transistor of the first
type or the second type, a source/drain path of which is connected
between the second input node and the output node.
[0016] In this case, an output signal amplifier includes a circuit
comprising an input node, an output node, a field effect transistor
of a first type, a drain/source path of which is connected between
the output node and first potential and a gate of which responds to
the input node and a field effect transistor of a second type, a
drain/source path is connected between the output node and second
potential and a gate of which responds to the input node.
[0017] The output node of the pass transistor circuit is connected
to the input of the output signal amplifier, an input signal is
applied from outside of the cell to the third input node of the
pass transistor circuit and the input signal from outside cell is
applied to at least two of all of the first input node and the
second input node of the pass transistor circuit.
[0018] The output node of the output signal amplifier operates to
output an output signal to outside of the cell. One aspect of the
thought of the present invention is characterized in arranging
respective terminals by a conductor layer for drawing an input
signal from outside of the cell and an output signal to outside of
the cell. These are arranged as follows. That is, when a coordinate
system (coordinate axes) is determined in a direction of running a
supply line of the first potential and a supply line of the second
potential and a direction orthogonal thereto, the terminals are
arranged to include terminal grid points disposed at constant
intervals in the coordinate system and at least one of terminal
grid coordinates of the respective terminals differ from terminal
grid coordinates arranged with at least two or more of the
terminals other than the above terminals.
[0019] According to the above-described semiconductor integrated
circuit of the present invention, when the coordinate system is
disposed in the running direction of the potential supply line and
the direction orthogonal thereto, input and output terminals are
not disposed on the same coordinates. In other words, the input and
output terminals are not aligned in a row, more specifically, these
are not aligned in a row in a direction in parallel with the
potential supply lines or a boundary line (contour) of the cell.
Therefore, by providing an input to the gate of the pass transistor
and an input to the source/drain of the pass transistor in
directions of the coordinate system under the space rule of the
conductor layer, the size of the cell can be reduced with regard to
the direction of potential supply lines. In this case, the space
rule refers to a rule of a minimum distance to prevent shortcircuit
from causing in consideration of a deviation in matching a mask and
a deviation in a process fabrication accuracy. Generally, with
regard to the direction orthogonal to the direction of running the
potential supply lines, the size of the cell is determined commonly
in respect of all of cell groups used in blocks in the chip and
accordingly, being capable of reducing the size in the direction of
the potential supply lines, signifies being capable of reducing the
area of the cell. Further, when wirings are provided among cells at
an upper layer, the wirings need to draw from the input and output
terminals and also in this case, since the input and output
terminals are not disposed on the same coordinates, the wirings can
be drawn from the respective terminals not only in the longitudinal
direction but also in the transverse direction and there is
achieved an advantage of promoting the degree of freedom of
wirings.
[0020] According to a preferable embodiment of the present
invention, when the coordinate system is determined in the
direction orthogonal to the direction of running the supply line of
the first potential and the supply line of the second potential, a
terminal from outside of the cell for inputting an input signal
applied to the third input node of the pass transistor circuit, is
arranged to shift to a larger side or a smaller side in view of the
coordinate system than a terminal from outside of the cell for
inputting an input signal applied to the first input node and the
second input node of the pass transistor circuit.
[0021] That is, according to the above-described semiconductor
integrated circuit of the present invention, as will be explained
later in the example of FIG. 1 through FIG. 3, the layout can be
conducted reasonably since a wiring drawn from source/drain of a
transistor of the pass transistor circuit to an input terminal and
a wiring drawn from gate to the input terminal do not intersect
with each other, whereby the size of the cell can be reduced.
[0022] Further, according to other preferable embodiment of the
present invention, when two types of field effect transistors
constituting the output signal amplifier determine the coordinate
system in the direction of running the supply line of the first
potential and the supply line of the second potential, the
transistors are arranged to shift to at least one of the boundaries
of the cell on a side where the coordinate values are minimized or
on a side where the coordinate values are maximized.
[0023] That is, according to the above-described embodiment of the
present invention, the output signal amplifier is arranged to shift
to the cell boundary with regard to the direction of running the
potential supply line and accordingly, even when a plurality of the
pass transistor circuits are present, the output signal amplifier
does not hinder wire connection among the plurality of pass
transistor circuits and accordingly, the cell can reasonably be
laid out to a small area.
[0024] Further, according to other preferable embodiment of the
present invention, when a plurality of pass transistors circuit are
present, the pass transistor circuits are developed to arrange
successively in the direction of running the supply line of the
first potential and the supply line of the second potential.
[0025] According thereto, even when the plurality of pass
transistor circuits are present, a number thereof can be increased
flexibly in the developing direction and accordingly, even when the
number of the pass transistor circuits is increased, a cell library
can regularly be laid out. Thereby, a time period consumed in
layout design of the pass transistor logical operation circuit cell
can be reduced.
[0026] Further, when the plurality of pass transistor circuits are
present and the pass transistor circuits are developed to arrange
in the direction of running the supply line of the first potential
and the supply line of the second potential, a width of a
source/drain region of a field effect transistor constituting the
pass transistor circuit in the direction of running the supply line
of the first potential and the supply line of the second potential
is changed in accordance with locations in the same source/drain
region. That is, the width is widened at a portion having contact
and is narrowed at a portion having no contact.
[0027] According to the above-described constitution, the layout
can be conducted such that the width of the source/drain region
becomes a necessary source/drain width simply for constituting the
transistor rather than a width prescribed by source/drain including
contact and accordingly, in applying a space rule between source
and drain (referred to as SD space rule), a source/drain region of
a contiguous pass transistor circuit is made contiguous to the
source/drain region of a portion having no contact by which the
size in the running direction of the potential supply line can be
reduced.
[0028] Further, the above-described cell is preferably constituted
as follows. When a field effect transistor of a first type and a
field effect transistor of a second type are arranged contiguously
to a CMOS logical operation circuit cell constituting a logic by
coupling them in a complementary relationship, the following
constitution is preferable.
[0029] That is, a boundary of a semiconductor region of the second
type surrounding the first type of the field effect transistor
constituting the CMOS logical operation circuit and a semiconductor
region of the first type surrounding the second type of the field
effect transistor, and a boundary of a semiconductor region of the
second type surrounding the first type of the field effect
transistor constituting the pass transistor logical operation
circuit and a semiconductor region of the first type surrounding
the second type of the field effect transistor, are constituted to
linearly connect at a connecting portion.
[0030] According to the above-described semiconductor integrated
circuit of the present invention, when the cells are contiguous to
each other, the well boundaries are linearly connected and
therefore even when a minimum width of a region surrounding a
transistor (referred to as a well minimum width) prescribed by the
design rule, is not satisfied by a single cell, the rule can be
satisfied by contiguously arranging a plurality of cells.
Accordingly, as a result, the cell area can be reduced. When the
embodiment according to the present invention is not used, in the
case of arranging a pass transistor logical operation circuit cell
and a CMOS logical operation circuit cell within the same block on
the same chip, design rule error may be caused, for example, at a
location where a single cell which cannot satisfy the rule of the
well minimum width is arranged isolatedly. However, when the cell
layout according to the present invention is carried out, the
problem is resolved.
[0031] Further, as will be explained later in reference to FIG. 4
and FIG. 5, other preferable aspect of the present invention is
characterized in that a boundary (referred to as well boundary) of
a semiconductor region of the second type (referred to as second
well) surrounding a field effect transistor of the first type
constituting the pass transistor logical operation circuit and a
semiconductor region of the first type (referred to as first well)
surrounding the field effect type transistor of the second type, is
brought to a side of the first semiconductor or to a side of the
second semiconductor at inside of the cell and is arranged to be
nonlinear at inside of the cell.
[0032] Thereby, regions of the field effect transistors
constituting the pass transistor circuit can effectively be
provided within the cell. That is, according to the CMOS logical
operation circuit cell, normally, a transistor of the first type
and a transistor of the second type are in a complementary
relationship and their numbers coincide with each other. Therefore,
transistors having the same numbers can be laid out on both sides
of a well boundary drawn linearly with no problem. However, in the
case of the pass transistor logical operation circuit cell, a
number of transistors of a type the same as a type of transistors
constituting the pass transistor circuit, is larger than a number
of transistors of a type different therefrom. Meanwhile, when the
boundary of the well is linearly laid out in the cell to be
linearly connected to the CMOS logical operation circuit cell, even
when there is constituted a distribution ratio of the first well
and the second well suitable for the CMOS logical operation
circuit, it becomes a distribution ratio which is not suitable for
the pass transistor logical operation circuit cell in which a
number of one type is larger than a number of other type. However,
when the above-described embodiment of the present invention is
used, a region for a transistor constituting the pass transistor
circuit can be widened at inside of the cell and accordingly, a
difference in the numbers of transistors can successively be
realized.
[0033] Further, as will be explained in details in reference to
FIG. 2, the semiconductor integrated circuit according to the
present invention uses a cell comprising a pass transistor logical
operation circuit having at least one set of pairs each of a pass
transistor circuit and an inverter circuit of the signal polarity
and at least one output signal amplifier. According to the pass
transistor operation circuit of the logical operation circuit,
there are provided a first input node, a second input node and a
third input node, an output node, a field effect type transistor of
a first type or a second type, a source/drain path of which is
connected between the first input node and the output node and a
field effect transistor of the first type or the second type, a
source/drain path of which is connected between the second input
node and the output node.
[0034] In this case, the signal polarity inverting circuit includes
a circuit comprising, for example, an input node, an output node, a
field effect type transistor of a first type, a drain/source path
of which is connected between the output node and first potential
and a gate of which responds to the input node and a field effect
transistor of a second type, a drain/source path of which is
connected between the output node and the second potential and a
gate of which responds to the input node.
[0035] In this case, the output signal amplifier includes a circuit
comprising an input node, an output node, a field effect transistor
of a first type, a drain/source path of which is connected between
the output node and first potential and a gate of which responds to
the input node and a field effect transistor of a second type, a
drain/source path of which is connected between the output node and
second potential and a gate of which responds to the input
node.
[0036] Further, the output node of the pass transistor circuit is
connected to the input of the output signal amplifier. In this way,
it signifies that by inserting the signal polarity inverting
circuit to inside of the cell, one of input terminals constituting
signal connection to outside of the cell is reduced in respect of a
set of a pair of the pass transistor circuits and the signal
polarity inverting circuit. This signifies that an amount of wiring
at outside of the cell is reduced in comparison with the case in
which the signal polarity inverting circuit is laid out at outside
of the cell and connected therefrom to two of the input terminals
of one pass transistor circuit and wiring is easy to carry out
since a crowdedness of wiring at outside of the cell can be
reduced, which is effective. Further, it is preferable that a
difference between delay times of complementary signals which are
to be inputted to two input terminals of one pass transistor
circuit, is small. Because, when the difference between the delay
times is large, although the above-described pass transistor
circuits are originally fabricated by assuming that only one of
them is made ON, there causes a case in which both are made ON or
the case both are made OFF. Now, when gate inputs of two pass
transistors to which the above-described complementary signals are
inputted, are drawn to outside of the cell independently from each
other, it is conceivable that complementary signals are transmitted
to these two inputs by using separate wirings. In such a case, when
there is considerable discrepancy in arrival times of signals by
reason in which lengths of the separate wirings differ, there can
be brought about an unpreferable situation in which both are made
ON or both are made OFF as mentioned above. However, according to
the semiconductor integrated circuit of the above-described
embodiment of the present invention, the signal polarity inverting
circuit is inserted to inside of the cell and accordingly, the
difference between the delay times to the gate inputs of the two
pass transistors can be restrained to a small value of only a delay
time of the signal polarity inverting circuit at most.
[0037] Further, as in later detailed explanation of a constitution
in reference to FIG. 1 and FIG. 2, in a cell comprising a pass
transistor logical operation circuit having at least a set of pairs
each of a pass transistor circuit and a signal polarity inverting
circuit and at least one output signal amplifier, the signal
polarity inverting circuit in the logical operation circuit
includes a circuit comprising an input node, an output node, a
field effect transistor of a first type, a drain/source path of
which is connected between the output node and first potential and
a gate of which responds to the input node and a field effect
transistor of a second type, a drain/source path of which is
connected between the output node and second potential and the gate
of which responds to the input node.
[0038] The output signal amplifier in the logical operation circuit
includes a circuit comprising an input node, an output node, a
field effect transistor of a first type, a drain/source path of
which is connected between the output node and first potential and
a gate of which responds to the input node and a field effect
transistor of a second type, a drain/source path is connected
between the output node and second potential and a gate of which
responds to the input node.
[0039] The output node of the pass transistor circuit is connected
to the input of the output signal amplifier, the first type of the
field effect transistor constituting the output signal amplifier is
provided with a gate width larger than that of the first type of
the field effect transistor constituting the signal polarity
inverting circuit and the second type of the field effect
transistor constituting the output signal amplifier is provided
with a gate width larger than that of the second type of the field
effect transistor constituting the signal polarity inverting
circuit.
[0040] One aspect of the present invention clearly provides a
guiding principle in how to design the channel width of the field
effect transistor constituting the signal polarity inverting
circuit. That is, a circuit outside of the cell driven by the
output signal amplifier is not known at a time point of the layout,
in consideration of fan-out or a wire capacity at outside of the
cell, there must be assumed a case of driving a comparatively large
load capacity, in contrast thereto, the signal polarity inverting
circuit may only drive the gate of the pass transistor circuit at
inside of the cell. When the channel width of the field effect
transistor constituting the signal polarity inverting circuit is
made larger than the channel width of the field effect transistor
constituting the output signal amplifier, regardless of the
relationship of the load capacity, large capacity is driven by a
small transistor and small load capacity is driven by large
capacity, as a result, there poses a problem in which a delay time
period of a total is increased. In contrast thereto, by conducting
layout such that the channel width of the field effect transistor
constituting the signal polarity inverting circuit is made smaller
than the channel width of the field effect transistor constituting
the output signal amplifier, the respectives can be constituted by
transistor sizes pertinent to driven load capacities and the delay
time period can be reduced.
[0041] Further, according to a preferable embodiment of the present
invention, the output node of the pass transistor circuit is
connected to the input of the output signal amplifier and the field
effect transistor constituting the pass transistor circuit, is
arranged between field effect transistors of a first type and a
second type constituting the signal polarity inverting circuit with
regard to a direction orthogonal to a direction of running a supply
line of the first potential and a supply line of the second
potential.
[0042] By arranging them in this way, the space rule in view of
layout between the source/drain region and the semiconductor region
(well or substrate) surrounding thereof is not adopted
unnecessarily, wire connection among pass transistor circuits and
installation of an electricity feeding line to the source of the
signal polarity inverting circuit can reasonably be carried out and
accordingly, as a result, the cell area can be reduced.
[0043] Further, preferably, the output signal amplifier in the
logical operation circuit includes a circuit comprising an input
node, an output node, a first field effect transistor of a first
type, a drain/source path of which is connected between the output
node and first potential and a gate of which responds to the input
node, a second field effect transistor of a second type, a
drain/source path of which is connected between the output node and
second potential and a gate of which responds to the input node and
a third field effect transistor of the first type, a drain/source
path of which is connected between the input node and the first
potential and a gate of which responds to the output node. Further,
according to the output signal amplifier, wire connection from the
drain of the third field effect transistor to the gates of the
first field effect transistor and the second field effect
transistor is realized by passing the wire connection below a first
potential supply line by using a material for the gate terminal of
the transistor.
[0044] In this way, by using the gate material as a wiring, the
portion below the potential supply line can effectively be utilized
and accordingly, there can be resolved a problem in which wiring
operation becomes difficult which is caused when wirings at
vicinities of the first field effect transistor and the third field
effect transistor of the output signal amplifier are crowded.
[0045] Other objects and novel characteristics of the present
invention will become apparent by the following embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] FIG. 1 is a layout diagram of a logical operation circuit
cell according to an embodiment of the present invention. FIG. 2 is
a circuit diagram of the logical operation circuit cell according
to the embodiment of the present invention. FIG. 3 is a layout
diagram of the logical operation circuit cell according to the
embodiment of the present invention. FIG. 4 is a layout diagram of
a logical operation circuit cell according to an embodiment of the
present invention. FIG. 5 is a circuit diagram of the logical
operation circuit cell according to the embodiment of the present
invention. FIG. 6 is a layout diagram of the logical operation
circuit cell according to the embodiment of the present invention.
FIG. 7 is a layout diagram arranging a plurality of the logical
operation circuit cells according to the embodiment of the present
invention. FIG. 8 is a layout diagram arranging and connecting a
plurality of the logical operation circuit cells according to the
embodiment of the present invention. FIG. 9 illustrates sectional
views of the logical operation circuit cell according to the
embodiment of the present invention. FIG. 10 is a layout diagram of
a conventional CMOS logical operation circuit (3 inputs NAND). FIG.
11 is a layout diagram of a conventional CMOS logical operation
circuit (3 inputs NOR). FIG. 12 is a layout diagram arranging the
logical operation circuit cells according to the embodiment of the
present invention by inverting the cells horizontally. FIG. 13 is a
layout diagram arranging the logical operation circuit cells
according to the embodiment of the present invention by inverting
the cells vertically. FIG. 14 is a layout diagram arranging logical
operation circuit cells according to the embodiment of the present
invention by inverting the cells vertically.
BEST MODE FOR CARRYING OUT THE INVENTION
[0047] An explanation will be given of embodiments according to the
present invention in reference to the drawings as follows.
[0048] FIG. 1 illustrates layout of a pass transistor logical
operation circuit cell when three of pass transistor circuits are
present in respect of one output signal amplifier.
[0049] FIG. 2 illustrates a circuit in correspondence with FIG. 1.
Basically, there are provided a logical circuit portion (PC21
through PC23) constituted by nMOS's, input amplifiers (inverters
201 through 203) constituted by CMOS's and an output amplifier
(BC21). First, a description will be given of correspondence
between layout and circuit.
[0050] FIG. 3 shows correspondence between FIG. 1 and FIG. 2.
Although layout of FIG. 3 is the same as that of FIG. 1, the layout
shows transistors and input and output terminals along with
numerals. Correspondence between these and transistors and input
and output terminals in FIG. 2 is as follows. p21 of FIG. 2
corresponds to 301 of FIG. 3, n21 of FIG. 2 corresponds to 302 of
FIG. 3, n22 of FIG. 2 corresponds to 303 of FIG. 3, n23 of FIG. 2
corresponds to 304 of FIG. 3, n24 of FIG. 2 corresponds to 307 of
FIG. 3, n25 of FIG. 2 corresponds to 308 of FIG. 3, n26 of FIG. 2
corresponds to 311 of FIG. 3, n27 of FIG. 2 corresponds to 312 of
FIG. 3, Out2 of FIG. 2 corresponds to 316 of FIG. 3, In21 of FIG. 2
corresponds to 317 of FIG. 3, In 22 of FIG. 2 corresponds to 318 of
FIG. 3, In23 of FIG. 2 corresponds to 319 of FIG. 3, In24 of FIG. 2
corresponds to 320 of FIG. 3, In25 of FIG. 2 corresponds to 321 of
FIG. 3, In26 of FIG. 2 corresponds to 322 of FIG. 3 and In27 of
FIG. 2 corresponds to 323 of FIG. 3.
[0051] Further, the inverter 201 is constituted by transistors 305
and 306 of FIG. 3, The inverter 203 of FIG. 2 is constituted by
transistors 313 and 314 of FIG. 3, and the inverter 202 of FIG. 2
is constituted by transistors 309 and 310 of FIG. 3 and p22 of FIG.
2 corresponds to 315 of FIG. 3.
[0052] The semiconductor integrated circuit according to the
present invention is laid out by the following thought. According
to the present invention, there is used a cell (FIG. 1 and FIG. 2)
comprising a logical operation circuit having at least one of pass
transistor circuits (PC21, PC22, PC23 of FIG. 2) and at least one
output signal amplifier (PC21 of FIG. 2). In this case, as shown by
FIG. 1 through FIG. 3, a pass transistor circuit in the logical
operation circuit (PC21, PC22, PC23 of FIG. 2) includes a first
input node, a second input node and a third input node, an output
node, a field effect transistor of a first type or a second type
(in FIG. 2, n22, n24 and n26), a source/drain path of which is
connected between the first input node and the output node and a
field effect transistor of the first type or the second type (in
FIG. 2, n23, n25 and n27 of n type), a source/drain path of which
is connected between the second input and the output node.
[0053] The output signal amplifier (BC21 of FIG. 2) in the logical
operation circuit, includes an input node, an output node, a field
effect transistor of a first type (in FIG. 2, p21 of p type), a
source/drain path is connected between the output node and first
potential and a gate of which responds to the input node and a
field effect transistor of a second type (in FIG. 2, n21 of n
type), a drain/source path is connected between the output node and
second potential and a gate of which responds to the input
node.
[0054] Further, the output node of the pass transistor circuit is
connected to the input of the output signal amplifier, an input
signal from outside of the cell is applied to the third input node
of the pass transistor circuit and input signals from outside of
the cell are applied to at least two of all of the first input
nodes and the second input nodes of the pass transistor circuits
(at least two of In21, In22, In23, In24, In25, In26 and In27 of
FIG. 2).
[0055] The output node (Out2 of FIG. 2) of the output signal
amplifier operates to output an output signal to outside of the
cell. Respective terminals by a conductor layer (for example, 1-th
layer of metal wiring) for drawing the input signals from outside
of the cell and the output signal to outside of the cell, are
arranged as follows. That is, when a coordinate system is
determined in a direction of running a first potential supply line
and a second potential supply line and a direction orthogonal
thereto, the respective terminals are arranged to include terminal
grid points disposed at constant intervals in the coordinate
system, in which terminal grid coordinates of at least one of the
respective terminals differ from terminal grid coordinates where at
least two or more of terminals are arranged (101, 102, 103 etc of
FIG. 1).
[0056] According to the semiconductor integrated circuit of the
embodiment of the present invention as mentioned above, when a
coordinate system is set in a direction of running the power supply
lines and a direction orthogonal thereto, input and output
terminals are not disposed on the same coordinates. Therefore, for
example, by providing the space rule of the conductor layer in
respect of input to a gate of a pass transistor and input to a
source and a drain of the pass transistor in a direction (vertical
direction in FIG. 1) of the above-described coordinate system, the
size of the cell can be reduced in the direction of the potential
supply lines (horizontal direction in FIG. 1). Generally, with
regard to the direction of running the potential supply lines and
the line orthogonal thereto (vertical direction in FIG. 1), the
size of the cell is determined commonly in respect of all of cell
groups used in blocks in a chip and accordingly, being capable of
reducing the size in the direction of the potential supply lines
(horizontal direction in FIG. 1), signifies being able to reduce
the area of the cell. Further, when wirings are provided among
cells at an upper layer, the wirings need to draw from the input
and output terminals and also in this case, the input and output
terminals are not disposed on the same coordinates and accordingly,
the wirings can be drawn from the respective terminals not only in
the vertical direction but also in the horizontal direction and
there is achieved an advantage in which the degree of freedom of
wiring is promoted.
[0057] Further, a terminal (which corresponds to 101 of FIG. 1,
In23 of FIG. 2) from outside of the cell for an input signal
applied to the third input node of the pass transistor circuit, is
arranged to shift to a larger side or a smaller side in the
coordinate system rather than terminals (which corresponds to 102
or 103 of FIG. 1, In26 and In27 of FIG. 2) from outside of the cell
for input signals applied to the first input node and the second
input node of the pass transistor circuit.
[0058] According to such a semiconductor integrated circuit, a wire
which pulls the signal out from source/drain of a transistor in the
pass transistor circuit (which corresponds to, for example, 108 of
FIG. 1, PC23 of FIG. 2) to an input terminal (102 or 103) and a
wire drawn from gate to an input terminal (101 of FIG. 1) do not
intersect with each other and therefore, layout can be carried out
reasonably by which the size of the cell can be reduced.
[0059] Further, the embodiment is characterized in that two types
of field effect transistors (104, 105 of FIG. 1) constituting the
output signal amplifier are arranged to shift to at least one of a
boundary of the cell on a side of smallest coordinate values and a
boundary of the cell on a side of largest coordinate values (left
side in FIG. 1) when a coordinate system is determined in the
direction of running the first potential supply line and the second
potential supply line.
[0060] According to the above-described semiconductor integrated
circuit in accordance with the embodiment of the present invention,
the output signal amplifier is arranged to shift to the cell
boundary with regard to the running direction of the potential
supply line (horizontal direction of FIG. 1) (104, 105 of FIG. 1)
and therefore, even when a plurality of the above-described pass
transistor circuits are present (PC21, PC22, PC23 of FIG. 2), wire
connection among the plurality of pass transistors is not hampered
and therefore, the cell can be laid out reasonably in a small
area.
[0061] Further, according to the embodiment, when the plurality of
pass transistor circuits are present (for example, PC21, PC22, PC23
of FIG. 2), the pass transistor circuits are developed to arrange
in the direction of running the first potential supply line and the
second potential supply line. In FIG. 1, the pass transistor
circuits are developed to arrange in an order of 106, 107 and
108.
[0062] According to the above-described semiconductor integrated
circuit in accordance with the embodiment of the present invention,
the output signal amplifier is arranged at an end of the cell (104,
105 of FIG. 1), even when a plurality of pass transistor circuits
are present (for example, PC21, PC22, PC23 of FIG. 2), a number
thereof can flexibly be increased in the developing direction and
therefore, even when the number of the pass transistor circuits is
increased, the cell library can regularly be laid out. Thereby, a
time period consumed in layout design of a pass transistor logical
operation circuit cell can be reduced.
[0063] Further, according to the embodiment, a width of a
source/drain region of a field effect transistor constituting a
pass transistor circuit (PC22 of FIG. 2 and 107 of FIG. 1
correspond thereto) in the direction of running the first potential
supply line and the second potential supply line (leftist side of
source/drain region in 107 of FIG. 1) is changed depending on
locations in the same source/drain region. That is, in FIG. 1, the
width is widened at an upper portion having contact and is narrowed
at a lower portion having no contact.
[0064] In this way, the width of the source/drain region can be
laid out by a source/drain width necessary for simply constituting
a transistor rather than a width prescribed by source and drain and
therefore, in applying the space rule (referred to as SD space rule
between source and drain) by making a source/drain region of a
contiguous pass transistor circuit to be contiguous to a
source/drain region of a portion having no contact, the size in a
direction of running of a potential supply line (horizontal
direction in FIG. 1) can be reduced.
[0065] According to the embodiment, at inside of the cell, there
are a pair of at least one set of pass transistor circuits (PC21,
PC22, PC23 of FIG. 2) and a signal polarity inverting circuit (201,
202, 203 of FIG. 2) and at least one output signal amplifier (BC21
of FIG. 2). The signal polarity inverting circuit (201, 202, 203)
includes a circuit comprising an input node, an output node, a
field effect transistor of a first type, a drain/source path of
which is connected between the output node and first potential and
a gate of which responds to the input node and a field effect
transistor of a second type, a drain/source path of which is
connected between the output node and second potential and a gate
of which responds to the input node.
[0066] In this way, by inserting the signal polarity inverting
circuit to inside of the cell, a number of input terminals
constituting signal connections to outside of the cell is reduced
by one per a pair of one set of a pass transistor circuit and a
signal polarity inverting circuit. This signifies that an amount of
wiring at outside of the cell is reduced in comparison with the
case in which the signal polarity inverting circuit is laid out at
outside of the cell and connected therefrom to two input terminals
of one pass transistor circuit, the degree of crowdedness of
wirings at outside of the cell can be reduced and accordingly,
wiring operation is easy to carry out. Further, it is preferable
that a difference between delay time periods is small in
complementary signals to be inputted to two input terminals of one
pass transistor circuit. Because when the difference between the
delay time periods is large although the above-described pass
transistor circuit is originally fabricated by assuming that either
one of them is made ON, there causes a case in which the both are
made ON or the case in which both are made OFF. Now, when gate
inputs of two pass transistors to which the above-described
complementary signals are inputted, are drawn to outside of the
cell independently from each other, it is conceivable that the
complementary signals are transmitted to these two inputs by using
separate wirings. In such a case, when there is a significant
discrepancy between arrival times of the signals owing to the
reason that lengths of the separate wirings differ, there can be
brought about an unpreferable situation in which both are made ON
or both are made OFF as mentioned above. However, according to the
embodiment of the present invention, described above, the signal
polarity inverting circuit is inserted to inside of the cell and
accordingly, the difference between the delay time periods to the
gate inputs of the two pass transistors can be restrained small
only to a delay time period of the signal polarity inverting
circuit at most.
[0067] In this case, the first type field effect transistor 104
constituting the output signal amplifier, is provided with a gate
width which is larger than that of a first type field effect
transistor 109 constituting the signal polarity inverting circuit.
Further, the second type field effect transistor 105 constituting
the output signal amplifier, is characterized in having a gate
width which is larger than that of a second type field effect
transistor 110 constituting the signal polarity inverting circuit.
The gate width can be defined as, for example, a length in a length
direction of a polysilicon layer at a portion thereof where a
diffused layer and the polysilicon layer constituting a gate
electrode overlap. As a characteristic, gain of the output signal
amplifier is made larger than gain of the signal polarity inverting
circuit.
[0068] That is, a circuit outside of the cell which is driven by
the output signal amplifier is not known at a time point of laying
out the cell, in consideration of fan-out and a capacity of wiring
at the outside portion, there must be assumed a case of driving
comparatively large load capacity, in contrast thereto, the signal
polarity inverting circuit may only drive the gate of the pass
transistor circuit at inside of the cell. When the channel width of
the field effect transistor constituting the signal polarity
inverting circuit is made larger than the channel width of the
field effect transistor constituting the output signal amplifier,
large capacity is driven by a small transistor and small load
capacity is driven by large capacity regardless of the
above-described relationship of load capacity, as a result, there
poses a problem in which a delay time period of a total is
increased. In contrast thereto, the channel width of the field
effect transistor constituting the signal polarity inverting
circuit is laid out to be smaller than the channel width of the
field effect transistor constituting the output signal amplifier by
which the respectives can be provided with transistor sizes
pertinent for load capacity and the delay time period can be
reduced.
[0069] According to the embodiment, the output node of the pass
transistor circuit is connected to the input of the output signal
amplifier, a field effect transistor (111) constituting the pass
transistor circuit (PC21 of FIG. 2), is arranged between the first
type and the second type field effect transistors (109 and 110)
constituting the signal polarity inverting circuit in a direction
orthogonal to the direction of running the first potential supply
line and the second potential supply line.
[0070] By arranging them in this way, the space rule in view of
layout between a source/drain region and a semiconductor region
(well or a substrate) surrounding thereof is not unnecessarily
adopted, connection among the pass transistor circuits and
installation of an electricity feeding line to the source of the
signal polarity inverting circuit can be conducted reasonably and
therefore, as a result, the cell area can be reduced. Now, consider
a case in which when the field effect transistor (110) constituting
the pass transistor circuit is of the second type, the transistor
is arranged not between the two transistors constituting the signal
polarity inverting circuits but thereabove or therebelow. First,
consider as case in which the transistor is arranged thereabove.
This signifies that in the first place, transistors of a second
type are arranged above and below a transistor of a first type and
accordingly, semiconductor regions surrounding the transistor need
to provide separately to the respective two transistors of the
second type. Generally, a space rule on a layout between a
source/drain region of a transistor and a semiconductor region
(well or a substrate) surrounding thereof (now, this is referred to
as a WELL-SD region space rule) becomes significantly larger than
the minimum rule for the layout. Therefore, when arranged in this
way, at least two of the WELL-SD regions are needed between the
transistor constituting the pass transistor and the first type
transistor of the signal polarity inverting circuit and further two
of the WELL-SD region space rule are needed between the first type
transistor of the signal polarity inverting circuit and the second
transistor. Thereby, there poses a problem in which the size of the
cell in the vertical direction is increased. Next, consider a case
in which it is arranged therebelow. In this case, the second type
transistor constituting the pass transistor circuit and the second
type transistor constituting the signal polarity inverting circuit
can be realized in the same semiconductor region (well or a
substrate) and accordingly, only two of the WELL-SD region space
rule are needed between the first type transistor and the second
type transistor of the signal polarity inverting circuit, which is
more preferable than in the case of arranging it thereabove.
However, in this case, a wiring for feeding electricity to the
source of the second type transistor constituting the signal
polarity inverting circuit (referred to as source electricity
feeding wiring) needs to draw from the second potential supply line
to above the transistor constituting the pass transistor circuit.
However, when considering a case in which a plurality of pass
transistor circuits are present and wire connection needs to carry
out among them. In order to prevent the connected wiring (for
example, 112 in FIG. 1) from being intersected with the
above-described source electricity feeding wiring (for example, 113
of FIG. 1), the wire connection needs to carry out among the pass
transistor circuits by drawing the wiring above the second type
transistor constituting the signal polarity inverting circuit or
either of the two wirings needs to connect in a wiring layer at one
upper layer. In the former case, the wiring needs to draw
significantly and therefore, the wiring is difficult and the cell
area is increased. Further, in the latter case, generally, the
wiring in an upper layer is used in wiring outside of the cell and
accordingly, when the wiring is used at inside of the cell, the
degree of freedom of wiring outside of the cell is significantly
deteriorated and accordingly, it is not preferable as well. In the
meantime, according to the above-described embodiment of the
present invention, either of these problems can be resolved and
accordingly, the embodiment is preferable.
[0071] When a further detailed explanation is given to the output
signal amplifier in the logical operation circuit in reference to
FIG. 1, there is provided a circuit comprising an input node, an
output node, the first field effect transistor 104 of the first
type, a drain/source path of which is connected between the output
node and first potential and a gate of which responds to the input
node, the second field effect transistor 105 of the second type, a
drain/source path of which is connected between the output node and
the second potential and a gate of which responds to the input node
and a third field effect transistor 114 of the first type, a
drain/source path of which is connected between the input node and
first potential and a gate of which responds to the output node.
According to the output signal amplifier, wire connection from a
drain of the third field effect transistor to the gates of the
first field effect transistor and the second field effect
transistor, is carried out by 115 passing below the first potential
supply line by using a gate material.
[0072] By using the gate material as wiring in this way, the lower
side of the potential supply line can effectively be utilized and
accordingly, there can be resolved a problem in which wiring
operation becomes difficult when wiring at the vicinities of the
first field effect transistor and the third field effect transistor
of the output signal amplifier is crowded.
[0073] An explanation will be given of other embodiment of the
present invention in reference to FIG. 4 and FIG. 5. FIG. 4 shows
layout of a pass transistor logical operation circuit cell when
five of pass transistor circuits are present for one output signal
amplifier. FIG. 5 shows a circuit in correspondence with FIG. 4.
First, correspondence between layout and circuits will be
given.
[0074] Correspondence between FIG. 4 and FIG. 5 is shown by FIG. 6.
Although layout of FIG. 6 is the same as that of FIG. 4, the layout
shows transistors and input and output terminals along with
numerals. Correspondence between these and transistors and input
and output terminals of FIG. 5 is as follows. p51 of FIG. 5
corresponds to 601 of FIG. 6, p52 of FIG. 5 corresponds to 602 of
FIG. 6, n51 of FIG. 5 corresponds to 603 of FIG. 6, n52 of FIG. 5
corresponds to 604 of FIG. 6, n53 of FIG. 5 corresponds to 605 of
FIG. 6, n54 of FIG. 5 corresponds to 606 of FIG. 6, n55 of FIG. 5
corresponds to 607 of FIG. 6, n56 of FIG. 5 corresponds to 608 of
FIG. 6, n57 of FIG. 5 corresponds to 609 of FIG. 6, n58 of FIG. 5
corresponds to 610 of FIG. 6, n59 of FIG. 5 corresponds to 611 of
FIG. 6, n510 of FIG. 5 corresponds to 612 of FIG. 6, n511 of FIG. 5
corresponds to 613 of FIG. 6, 501 of FIG. 5 corresponds to 614 and
615 of FIG. 6, 502 of FIG. 5 corresponds to 616 and 617 of FIG. 6,
503 of FIG. 5 corresponds to 618 and 619 of FIG. 6, 504 of FIG. 5
corresponds to 620 nd 621 of FIG. 6, 505 of FIG. 5 corresponds to
622 and 623 of FIG. 6, Out5 of FIG. 5 corresponds to 624 of FIG. 6,
In51 of FIG. 5 corresponds to 625 of FIG. 6, In52 of FIG. 5
corresponds to 626 of FIG. 6, In53 of FIG. 5 corresponds to 627 of
FIG. 7, In54 of FIG. 5 corresponds to 628 of FIG. 6, In55 of FIG. 5
corresponds to 629 of FIG. 6, In56 of FIG. 5 corresponds to 630 of
FIG. 6, In57 of FIG. 5 corresponds to 631 of FIG. 6, In58 of FIG. 5
corresponds to 632 of FIG. 6, In59 of FIG. 5 corresponds to 633 of
FIG. 6, In510 of FIG. 5 corresponds to 634 of FIG. 6 and In511 of
FIG. 5 corresponds to 635 of FIG. 6.
[0075] According to the embodiment, there is provided a cell (FIG.
4, FIG. 5 and 705 of FIG. 7) comprising a logical operation circuit
having at least one pass transistor circuit (PC51 of FIG. 5) and at
least one output signal amplifier (BC51 of FIG. 5).
[0076] The pass transistor circuit (PC51, PC52, PC53 of FIG. 5) in
the logical operation circuit includes a first input node, a second
input node and a third input node, an output node, a field effect
transistor of a first type or a second type (n52, n54, n56 of FIG.
5), a source/drain path of which is connected between the first
node and the output node and a field effect transistor of the first
type or the second type (n53, n55, 57 of FIG. 2), a source/drain
path of which is connected between the second input node and the
output node.
[0077] The output signal amplifier (BC51 of FIG. 5) in the logical
operation circuit includes a circuit comprising an input node, an
output node, a field effect transistor of a first type (p51 of FIG.
5), a drain/source path of which is connected between the output
node and first potential and a gate of which responds to the input
node and a field effect transistor of a second type (n51 of FIG.
5), a drain/source path of which is connected between the output
node and the second potential and a gate of which responds to the
input node.
[0078] The output node of the pass transistor circuit is connected
to the input of the output signal amplifier. In this case, each
cell is assumed to arrange contiguous to a CMOS logical operation
circuit cell constituting a logic by connecting a first type field
effect transistor and a second type field effect transistor in a
complementary relationship (refer to arrangement of 704 and 705 of
FIG. 7 explained below).
[0079] A boundary (referred to as well boundary) between a
semiconductor region of a second type (referred to as second well)
surrounding a field effect transistor of a first type constituting
the transistor logical operation circuit and a semiconductor region
of a first type (referred to as first well) surrounding a field
effect transistor of a second type, is brought into a first
semiconductor side or a second semiconductor side at inside of the
cell (401 of FIG. 4) and is arranged nonlinearly at inside of the
cell.
[0080] According to the above-described semiconductor integrated
circuit in accordance with the embodiment of the present invention,
a region of a field effect transistor constituting a pass
transistor circuit can effectively be provided at inside of the
cell. That is, according to a CMOS logical operation circuit cell,
normally, a transistor of a first type and a transistor of a second
type are brought into a complementary relationship and numbers of
these coincide with each other. Accordingly, transistors having the
same numbers can respectively be laid out with no problem on both
sides of a well boundary drawn linearly. However, in the case of a
pass transistor logical operation circuit cell, a number of
transistors of a type the same as that of transistors constituting
the pass transistor circuit becomes larger than a number of
transistors having a type different therefrom. Meanwhile, when the
cell boundary is laid out linearly even at inside of the cell to be
linearly connected to the CMOS logical operation circuit cell
having a contiguous boundary, even if there is constituted a
distribution ratio of a first well and a second well suitable for
the CMOS logical operation circuit cell, it becomes a distribution
ratio which is not suitable for the pass transistor logical
operation circuit cell in which one type of transistors are more
than other type of transistors. However, when the above-described
embodiment of the present invention is used, there is provided a
wide region for transistors constituting the pass transistor
circuit at inside of the cell and accordingly, a difference in the
number of transistors can successively be realized.
[0081] According to the layout of the cell of the embodiment (FIG.
4), the input and output terminals (402 through 406) are not
arranged to include the same terminal grid coordinates in respect
of the vertical direction of the drawings. According to the CMOS
logical operation circuit cell, even when all of inputs and outputs
include the same terminal grid coordinates in the vertical
direction (terminal grid coordinates in the horizontal direction
may naturally differ), there poses no problem since a number of
input and output terminals per cell is small (refer to FIG. 10),
however, in the case of the pass transistor logical operation
circuit cell, a number of input and output terminals per cell is
larger than that of the CMOS logical operation circuit cell which
poses a problem. Now, when four terminals of the input terminals
402, 403, 404 and 405 are used to arrange to include the same
terminal grid coordinates in respect of the vertical direction of
the drawing, a space rule at least prescribed by a design rule of a
wiring layer surrounding the terminals, is needed among them and
therefore, at least three of the space rules are needed in the
horizontal direction. However, when there are set terminal grid
coordinates which are different in the vertical direction as in 402
and 404 and 403 and 405 as in the embodiment, in arranging four of
these input terminals, only one of the above-described space rule
is sufficient. Accordingly, the cell size in the horizontal
direction can be reduced.
[0082] Further, according to the semiconductor integrated circuit
of the embodiment, the input terminal (404, 405 of FIG. 4) to the
source/drain region of the transistor constituting the pass
transistor circuit is arranged on the lower side of the drawing
than the input terminal (402, 403 of FIG. 4) to the gate. By
arranging in this way, a wiring drawn from the source/drain of the
transistor constituting the pass transistor circuit and a wiring
drawn from the gate do not intersect with each other and can
reasonably be laid out and therefore, the cell area can be
reduced.
[0083] Further, according to the semiconductor integrated circuit
of the embodiment, the output signal amplifier (407 and 408 of FIG.
4) is arranged at an end of the cell (in respect of the horizontal
direction). In the case of the embodiment in which five of the pass
transistor circuits are present in respect of the single cell, as
shown by the circuit of FIG. 5, wire connection among the five pass
transistors is increased. In such a case, when the output signal
amplifier is not arranged at an end of the cell but is arranged at
the center of the cell, or arranged within a portion where the five
pass transistor circuits are arranged, a wiring (409) in the output
signal amplifier and a wiring (410) between the pass transistor
circuits, are liable to intersect with each other and the wiring
operation becomes difficult. However, it is known that according to
the embodiment, such a problem is avoided.
[0084] Further, according to the semiconductor integrated circuit
of the embodiment, the output signal amplifier is arranged at a
right end and five of the pass transistor circuits are arranged to
develop on a right side thereof (411, 412, 413, 414, 415). In
considering this case in view of the case of FIG. 1 where three of
the pass transistor circuits are present, it is known that while
substantially a similar arrangement is provided to the output
signal amplifier on the left side and the three pass transistor
circuits are arranged to the right, two pass transistor circuits
are further added to the right. By constituting such an
arrangement, even when a plurality of the pass transistor circuits
are present, in view of layout, additional portions may be laid out
to a cell having pass transistor circuits of a smaller number.
Accordingly, a time period required for the cell layout can
significantly be reduced.
[0085] Further, according to the semiconductor integrated circuit
of the embodiment, a width of the source/drain region of the field
effect transistor constituting the pass transistor circuit in the
direction of running a supply line of the first potential and a
supply line of the second potential (for example, source/drain
region on the left side of 412), is changed depending on locations
in the same source/drain region. Thereby, the above source/drain
region can be made contiguous to the source/drain region of a
contiguous pass transistor circuit (a source/drain region on the
right of 411) at a portion having no contact whereby a size in the
running direction of the potential supply line is reduced.
[0086] Further, according to the semiconductor integrated circuit
of the embodiment, as mentioned above, the boundary (well boundary,
401) between the semiconductor region (referred to as a second type
well) surrounding the first type of the transistor and the
semiconductor region (referred to as a first type well) surrounding
the second type of the transistor, is bent to break nonlinearly at
inside of the cell. That is, in this case, a region of the first
type well is larger than a region of the second type well. Now,
according to the cell, there are seven of the first type
transistors and twelve of the second type transistors and a number
of the second type transistors is larger than that of the first
type transistors. According to the embodiment of the present
invention, by widening the first type well region, a region of
laying out the second type transistors can widely be provided.
Further, a boundary portion in respect with a contiguous cell
coincides with a well boundary line provided to the CMOS logical
cell and a rule for the minimum width of well in contiguously
arranging a plurality of cells can be satisfied with no
problem.
[0087] Further, according to the semiconductor integrated circuit
of the embodiment, a signal polarity inverting circuit is inserted
into the inside of the cell in pair with the pass transistor
circuit. That is, in FIG. 4, there is at inside of the cell a
signal polarity inverting circuit (constituted by 416 and 417) for
forming a complementary signal to a gate of one transistor thereof.
The advantage of constituting such a mode has already been
described.
[0088] Further, according to the semiconductor integrated circuit
of the embodiment, although the signal polarity inverting circuit
is inserted into the cell in pair with the pass transistor circuit,
a channel width of a transistor constituting the output signal
amplifier is larger than a channel width of a transistor
constituting the signal polarity inverting circuit. That is, in
FIG. 4, with regard to the first type field effect transistor, the
width of 407 is larger than that of 416 and with regard to the
second type field effect transistor, the width of 408 is larger
than that of 417. The advantage of constituting the mode has
already been described.
[0089] Further, according to the semiconductor integrated circuit
of the embodiment, the signal polarity inverting circuit is
inserted into the cell in pair with the pass transistor circuit and
a transistor (418) constituting the pass transistor circuit is
arranged between the first type transistor (416) and the second
type transistor (417) constituting the signal polarity inverting
circuit. The advantage of constituting the mode has already been
described.
[0090] An explanation will be given of other embodiment in
reference to FIG. 7. In FIG. 7, there are provided cells 701, 703
and 705 comprising logical operation circuits each having at least
one pass transistor circuit (for example, may be similar to
circuits shown by PC21, PC22, PC23 of FIG. 2) and at least one
output signal amplifier (for example, may be similar to the circuit
shown by BC21 of FIG. 2). An output node of the pass transistor
circuit is connected to the input of the output signal amplifier
similar to the example of FIG. 2.
[0091] FIG. 7 shows a behavior of arranging the pass transistor
logical operation circuit cells 701, 703 and 705 contiguous to
generally used CMOS logical operation circuit cells. Portions of
connecting wells 707, 710, 712 and 713 of the pass transistor
logical operation circuit cells and well boundaries of the CMOS
logical operation circuit cells 708, 709, 711 and 714 become
linear.
[0092] As shown by FIG. 7, the cells 701 and 703 or the cell 705
are arranged contiguous to a CMOS logical operation circuit cell
702 or cells 704 and 706 each constituting a logic by connecting a
first type of a field effect transistor and a second type of a
field effect transistor in a complementary relationship. In this
case, linear connection is realized at portions of connecting
boundaries 708, 709, 711 and 714 of semiconductor regions of the
second type surrounding the first type of the field effect
transistor constituting the CMOS logical operation circuit and
semiconductor regions of the first type surrounding the field
effect transistor of the second type, and boundaries 707, 710, 712
and 713 (referred to as well boundaries) of semiconductor regions
of the second type surrounding the first type of the field effect
transistor constituting the pass transistor logical operation
circuit and semiconductor regions of the first type surrounding the
second type of the field effect transistor.
[0093] According to the example, when cells are contiguous to each
other, the well boundaries are linearly connected and accordingly,
even in the case in which a minimum width of a region surrounding a
transistor prescribed by a design rule (referred to as rule for the
minimum width of well) is not satisfied only by a single cell, the
rule can be satisfied by contiguously arranging a plurality of the
cells. Accordingly, as a result, the cell area can be reduced. When
the embodiment according to the present invention is not used, in
arranging contiguously a pass transistor logical operation circuit
and a CMOS logical operation circuit cell in the same block on the
same chip, design rule error is caused at a particular location
(location where only one of a cell which cannot satisfy the
above-described rule for the minimum width of well is isolatedly
arranged). However, when the cell layout according to the present
invention is carried out, the problem is resolved.
[0094] FIG. 8 shows a behavior in which the pass transistor logical
operation circuit cells according to the present invention are
arranged contiguous to generally used CMOS logical operation
circuit cells and these cells are connected by using an upper layer
of a wiring layer. An input is designated by In and an output is
designated by Out. In the drawing, by overlapping four of cross
portions on FIG. 7, illustrated above, a relationship between a
lower layer and the upper layer becomes apparent. In this case,
there is shown an example in which a second layer is used in
wirings in the vertical direction and a third layer is used in
wirings in the horizontal direction. In this case, while wirings of
the CMOS logical operation circuit cells are drawn only in the
vertical direction, in the case of the pass transistor logical
operation circuit cells, the wirings are drawn in the horizontal
direction.
[0095] FIG. 9(a) shows a pass transistor logical operation circuit
cell the same as that in FIG. 1. FIG. 9(b) and FIG. 9(c)
schematically represent sectional views when the cell is cut along
a line designated by 901. FIG. 9(b) shows a case in which a second
layer of a wiring is not drawn to an output terminal 901 of FIG.
9(a) and FIG. 9(c) shows a case in which the wiring is drawn
thereto. 903 of FIG. 9(c) shows drawing of a wiring at a second
layer.
[0096] FIG. 12 shows a case in which a pass transistor logical
operation circuit cell 1201 and 1202 where the pass transistor
logical operation circuit cell 1201 is inverted in the horizontal
direction, are contiguously arranged and connected. Although
according to the embodiment, 1202 is produced by inverting 1201 in
the horizontal direction, a cell to be inverted may naturally be
other pass transistor logical operation circuit cell or a CMOS
operation circuit cell.
[0097] FIG. 13 shows a case in which a pass transistor logical
operation circuit cell 1301 and 1302 produced by inverting the pass
transistor logical operation circuit cell in the vertical
direction, are contiguously arranged and connected. Although
according to the embodiment, 1302 is produced by inverting 1301 in
the vertical direction, a cell to be inverted may naturally be
other pass transistor logical operation circuit cell or a CMOS
logical operation circuit cell.
[0098] FIG. 14 shows a case in which a pass transistor logical
operation circuit cell 1401 and 1402 produced by inverting the pass
transistor logical operation circuit cell in the vertical
direction, are contiguously arranged and connected. However, what
differs from the embodiment of FIG. 13 resides in arranging to
overlap electricity feeding portions for latch up measure to
semiconductor regions (well) surrounding transistors of upper and
lower two cells simultaneous with the vertical inversion. In this
way, there is achieved an advantage of capable of making the cell
area smaller than that in the case of FIG. 13.
[0099] Although a detailed explanation has been given of the
embodiments according to the present invention which have been
carried out by the inventors, the present invention is not limited
to the above-described specific embodiments but may naturally be
modified variously within the range of the technical thought.
[0100] For example, the field effect transistor of the pass
transistor circuit is not limited to MOSFET of silicon but MOSFET
by a compound semiconductor of GaAs can be used.
[0101] Further, the logical operation circuit having the pass
transistor circuit according to the present invention naturally
achieves effects in a reduction in a layout area, a reduction in a
wiring amount and reductions in power consumption and a delay time
period accompanied thereby by being applied to a random logic
circuit for decoding an instruction of an RISC type and controlling
an instruction executing unit in LSI of a general use processor, a
signal processing processor, an image processing processor or the
like.
Industrial Applicability
[0102] According to the present invention, there can be provided a
semiconductor integrated circuit having a pass transistor logical
operation circuit cell having a small area and capable of reducing
power consumption and delay.
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