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US4890148A Expired / Lapsed US ⏱️ 0.0 years remaining

Semiconductor memory cell device with thick insulative layer

Assignee: Hitachi Ltd
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Filing: 1988-07-07
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Granted: 1989-12-26
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Expires: 2008-07-07
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Abstract

Abstract A static RAM exhibiting a high reliability and suited to a higher density of integration is disclosed. In each memory cell of this static RAM, the cross coupling of a flip-flop circuit is made by gate electrodes of MISFETs constituting this flip-flop circuit. In addition, a source line is formed by the same step as that of a word line. A resistance value of a polycrystalline silicon layer which is a load resistor is changed in accordance with information to be stored. Furthermore, semiconductor regions for preventing soft errors attributed to alpha particles etc. are formed under the MISFETs constituting the flip-flop circuit, so that the channels are not adversely affected.

Inventors

  • 👤 Shuji Ikeda
  • 👤 Kouichi Nagasawa
  • 👤 Satoshi Meguro
  • 👤 Sho Yamamoto

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-31 11:13
CPC Classifications
H; H10; H10B; H10B10/00; H10B10/15; G; G11; G11C; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/41; G11C11/412; G11C11/4125; H10B10/12; H10D; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0165; H10D84/0167; H10D84/017; H10D84/0181; H10D84/0191; H10W; H10W20/00; H10W20/40; H10W20/41; H10W20/43

Claims Analysis

Total Claims: 19
Claim 1
Independent Claim 222 words
A semiconductor integrated circuit device comprising: word lines which are made of a double-layer film comprising a first film of polycrystalline silicon and a second film of a silicide formed as a compound of silicon and a refractory metal and which extend in a row direction over a semiconductor substrate; data lines which extend in a column direction over said semiconductor substrate and two of which constitute one set of complementary data lines, each set of complementary data lines being connected to an identical memory cell; a plurality of memory cells each of which comprises cross-coupled first and second MISFETs, first and second switching MISFETs being connected between said first and second MISFETs and said complementary data lines and having their gate electrodes connected to said word lines, said first and second MISFETs and said first and second switching MISFETs each comprising source and drain regions in said semiconductor substrate, and a gate electrode on a first insulation film on said semiconductor substrate; and first wiring lines which are formed on a second insulation film on said semiconductor substrate, which serve to supply a ground potential to said memory cells, and which are made of the same layers as those of said word lines, wherein a thickness of said second insulation film is thicker than a thickness of said first insulation film.
Claim 2
Dependent Claim 222 words
A semiconductor integrated circuit device comprising: word lines which are made of a double-layer film comprising a first film of polycrystalline silicon and a second film of a silicide formed as a compound of silicon and a refractory metal and which extend in a row direction over a semiconductor substrate; data lines which extend in a column direction over said semiconductor substrate and two of which constitute one set of complementary data lines, each set of complementary data lines being connected to an identical memory cell; a plurality of memory cells each of which comprises cross-coupled first and second MISFETs, first and second switching MISFETs being connected between said first and second MISFETs and said complementary data lines and having their gate electrodes connected to said word lines, said first and second MISFETs and said first and second switching MISFETs each comprising source and drain regions in said semiconductor substrate, and a gate electrode on a first insulation film on said semiconductor substrate; and first wiring lines which are formed on a second insulation film on said semiconductor substrate, which serve to supply a ground potential to said memory cells, and which are made of the same layers as those of said word lines, wherein a thickness of said second insulation film is thicker than a thickness of said first insulation film.
Claim 3
Dependent Claim 35 words
A semiconductor integrated circuit device according to claim 1, wherein one of said source or drain of each of said first and second MISFETs is connected to said first wiring lines through via contact holes.
Claim 4
Dependent Claim 18 words
A semiconductor integrated circuit device according to claim 2, wherein said first and second MISFETs are n-channel MISFETs.
Claim 5
Dependent Claim 54 words
A semiconductor integrated circuit device according to claim 2, further comprising: load elements which are respectively coupled to said first and second MISFETs; and a second wiring which serves to supply a power source potential to said load elements and which is formed over said first wiring with a third insulation film intervening therebetween.
Claim 6
Dependent Claim 54 words
A semiconductor integrated circuit device according to claim 4, wherein said word line is made of a layer which contains a refractory metal, and wherein said load elements and said second wiring are made of polycrystalline silicon and are unitarily formed, said first, second and third insulation films being made of silicon oxide films.
Claim 7
Dependent Claim 26 words
A semiconductor integrated circuit device according to claim 1, wherein said first wiring lines extend substantially in the same direction as that of said word lines.
Claim 8
Dependent Claim 15 words
A semiconductor integrated circuit device according to claim 2, wherein said refractory metal is molybdenum.
Claim 9
Dependent Claim 15 words
A semiconductor integrated circuit device according to claim 2, wherein said refractory metal is tantalum.
Claim 10
Dependent Claim 15 words
A semiconductor integrated circuit device according to claim 2, wherein said refractory metal is titanium.
Claim 11
Dependent Claim 15 words
A semiconductor integrated circuit device according to claim 2, wherein said refractory metal is tungsten.
Claim 12
Dependent Claim 20 words
A semiconductor integrated circuit device according to claim 2, wherein each of said word lines is made of silicide film.
Claim 13
Dependent Claim 264 words
A semiconductor integrated circuit device comprising: word lines which are made of a double-layer film comprising a first film of polycrystalline silicon and a second film of a silicide formed as a compound of silicon and a refractory metal and which extend in a row direction over a semiconductor substrate; data lines which extend in a column direction over said semiconductor substrate and two of which constitute one set of complementary data lines, each set of complementary data lines being connected to an identical memory cell; a plurality of memory cells each of which comprises cross-coupled first and second MISFETs, first and second switching MISFETs being connected between said first and second MISFETs and said complementary data lines and having their gate electrodes connected to said word lines, said first and second MISFETs and said first and second switching MISFETs each comprising source and drain regions in said semiconductor substrate, and a gate electrode on a first insulation film on said semiconductor substrate; first wiring lines which are formed on a second insulation film on said semiconductor substrate, which serve to supply a ground potential to said memory cells, which are made of the same layers as those of said word lines, wherein a thickness of said second insulation film is thicker than a thickness of said first insulation film; load elements which are respectively coupled to said first and second MISFETs; and a second wiring line which serves to supply a first fixed potential to said load elements and which is formed over said first wiring with a third insulation film intervening therebetween.
Claim 14
Dependent Claim 264 words
A semiconductor integrated circuit device comprising: word lines which are made of a double-layer film comprising a first film of polycrystalline silicon and a second film of a silicide formed as a compound of silicon and a refractory metal and which extend in a row direction over a semiconductor substrate; data lines which extend in a column direction over said semiconductor substrate and two of which constitute one set of complementary data lines, each set of complementary data lines being connected to an identical memory cell; a plurality of memory cells each of which comprises cross-coupled first and second MISFETs, first and second switching MISFETs being connected between said first and second MISFETs and said complementary data lines and having their gate electrodes connected to said word lines, said first and second MISFETs and said first and second switching MISFETs each comprising source and drain regions in said semiconductor substrate, and a gate electrode on a first insulation film on said semiconductor substrate; first wiring lines which are formed on a second insulation film on said semiconductor substrate, which serve to supply a ground potential to said memory cells, which are made of the same layers as those of said word lines, wherein a thickness of said second insulation film is thicker than a thickness of said first insulation film; load elements which are respectively coupled to said first and second MISFETs; and a second wiring line which serves to supply a first fixed potential to said load elements and which is formed over said first wiring with a third insulation film intervening therebetween.
Claim 15
Dependent Claim 18 words
A semiconductor integrated circuit device according to claim 12, wherein said first and second MISFETs are n-channel MISFETs.
Claim 16
Dependent Claim 35 words
A semiconductor integrated circuit device according to claim 12, wherein said load elements are made of the same layers as those of said second wiring lines and are formed with said second wiring lines integrally.
Claim 17
Dependent Claim 41 words
A semiconductor integrated circuit device according to claim 12, wherein said load elements and said second wiring are made of polycrystalline silicon and are unitarily formed and wherein said first, second and third insulation films are made of silicon oxide films.
Claim 18
Dependent Claim 71 words
A semiconductor integrated circuit device according to claim 2, wherein said gate electrodes of said first and second MISFETs are made of the same layer as that of said word line, and one of said source and drain regions of each of said first and second MISFETs connected with said first wiring is formed longer than the other in a direction in which said gate electrode of said each MISFET extends.
Claim 19
Dependent Claim 26 words
A semiconductor integrated circuit device according to claim 12, wherein said first wiring lines extend substantially in the same direction as that of said word lines.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1992-12-25 1993-06-26 1993-12-26 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1996-12-25 1997-06-26 1997-12-26 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2000-12-25 2001-06-26 2001-12-26 $7700.00 Window Closed / Lapsed

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