GB2271467A - Manufacturing method of a semiconductor device - Google Patents

Manufacturing method of a semiconductor device Download PDF

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Publication number
GB2271467A
GB2271467A GB9319730A GB9319730A GB2271467A GB 2271467 A GB2271467 A GB 2271467A GB 9319730 A GB9319730 A GB 9319730A GB 9319730 A GB9319730 A GB 9319730A GB 2271467 A GB2271467 A GB 2271467A
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United Kingdom
Prior art keywords
silicide
semiconductor device
forming
reactor
polycide structure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
GB9319730A
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GB9319730D0 (en
Inventor
Soo-Kwan Kim
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Samsung Electronics Co Ltd
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Samsung Electronics Co Ltd
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Filing date
Publication date
Application filed by Samsung Electronics Co Ltd filed Critical Samsung Electronics Co Ltd
Publication of GB9319730D0 publication Critical patent/GB9319730D0/en
Publication of GB2271467A publication Critical patent/GB2271467A/en
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/70Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/71Manufacture of specific parts of devices defined in group H01L21/70
    • H01L21/768Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
    • H01L21/76801Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing
    • H01L21/76829Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing characterised by the formation of thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers
    • H01L21/76834Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing characterised by the formation of thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers formation of thin insulating films on the sidewalls or on top of conductors

Abstract

A method for manufacturing an MOS semiconductor device, wherein the oxidation process of a silicide is included, comprises the steps of: forming a polycide structure on a semiconductor substrate (21) by forming a gate insulating layer (22), a conductive layer containing silicon (23), and a silicide layer (24) in order; and forming a silicon oxide (25) on the whole surface of the resultant structure by the dry oxidation in an oxygen and hydrogen chloride gas atmosphere. A gate line or interconnection layer of a polycide structure is obtained without the occurrence of structural defects, thereby improving the reliability of a semiconductor device. <IMAGE>

Description

1 p 2271467 ALkWFACTURING METHOD OF A SEM[ICONDUCTOR DEVICE This invention
relates to a manufacturing method of a semiconductor device, and more particularly, to a method for oxidizing a silicide which is formed to reduce the resistivity of an interconnection in a semiconductor device.
As the features of VLSI are realized by the development of integration technology of semiconductor devices, and particularly, as design rules continue to shrink (to 11im and less), the necessity of decreasing the resistance and capacitance in association with interconnection paths becomes ever more pressing. This is particularly true for MOS (metal oxide semiconductor) devices, in which the RC delay due to the interconnection paths can exceed the delay due to the gate switching during circuit operation. The higher the value of the interconnect R X C (resistance X capacitance) product, the more likely the circuit operating speed will be limited by this delay. Accordingly, low-resistivity of interconnection paths is critical in order to fabricate a dense, high performance device.
Recently, there are several approaches to reduce the resistivity of the interconnection to less than the 15 - 30Q/ 0 exhibited by polysilicon. Among 2 -7 these is a method in which the interconnection material is replaced by aluminum which has a low resistivity. However, due to the low melting and eutectic temperature of aluminum, all subsequent processes have to be held to less than 500"C. Since several processes (e.g. source-drain implant annealing, oxidation, and glass flow/reflow) must be carried out at temperatures above 500"C, aluminum is unsuitable as the interconnection material.
In another method for reducing the resistivity of an interconnection, the polysilicon is replaced by a refractory metal (e.g., W, Ta, Ti or Mo) or a refractory metal silicide composed of silicon and a refractory metal (e. g., WSi, TiSi,, MoSi, or TaSi2) and used as the interconnect material directly.
Also, a polycide structure is used as the interconnection in order to reduce resistivity, and is a multilayer structure consisting of a low resistance material (e.g., refractory metal silicide) on top of a doped polysilicon layer.
Generally, the refractory metals have high melting temperatures, but their oxides are typically of poor quality, and in some cases are volatile (for example, Mo and W oxides). In addition, consistent threshold voltages may be difficult to obtain in MOS transistors which use the refractory metal as a gate electrode, due to impurities in their sources. The use of refractory metal silicides alone as the gate/interconnection layer, suffers similar problems as experienced in connection with the use of a refractory metal alone. The polycide structure has therefore become the predominant interconnection film for replacing polysilicon because it does not give rise to such problems.
7 3 There are several methods for forming the silicide on silicon, each of which involve a deposition followed by a thermal step: 1) deposition of a pure metal on silicon; 2) simultaneous evaporation of the silicon and the refractory metal from two sources; and 3) sputter-depositing the silicide, either from a composite target or by co-sputtering.
In the meantime, often during VLSI processing, an insulating layer must be formed on the top surface of the polycide structure to isolate it from subsequently deposited polysilicon or metal layers. Vapour-deposited silicon oxide (SiO) and silicon nitride (Si3N,) can be used for this application, but thermally grown silicon oxide generally possesses better material properties, and therefore the thermally grown silicon oxide is mainly used as an insulating layer for isolation.
By heating all of the metal silicide films on the polysilicon or singlecrystal in an oxidizing atmosphere, silicon oxide is formed on the surface of the silicide. Therefore,, an insulating layer having good electrical and physical properties can be obtained.
FIG. I of the accompanying drawings represents a conventional thermal oxidizing process for the silicide of a polycide structure.
More particularly, at first, a wafer which contains a polycide structure on its surface is loaded into a reactor whose temperature is low (e.g., 650 I O'C) in a nitrogen gas (N,) atmosphere. Next, the temperature in the reactor is ramped up slowly.
1P 4 After the temperature in the reactor has reached a certain level (e.g., 900 20C) at which the silicide can be oxidized, the wafer is annealed at the same temperature for approximately 30 minutes.
Next, at the same temperature, the silicide is dry -oxidized in a nitrogen and oxygen gas (N2 and 02) atmosphere for 30 minutes more or less (that is, Si +02 _- S'OD - Next, at the same temperature, with the nitrogen gas turned off, the silicide is wet-oxidized in an oxygen and hydrogen gas (02 and H) atmosphere for approximately five minutes (that is, Si + 2HO = SiO2, + 2H, ).
Next, at the same temperature, with th e oxygen and hydrogen gas turned off, the wafer is annealed in a nitrogen gas atmosphere for a certain period of time, and with the temperature being ramped down, the wafer is unloaded from the reactor.
In the above-described polycide structure (see Silicon Processingfor the VLSI Era by S. Wolf and R.N. Tauber, Vol. 1, 1986, pp 395-396), the oxidation process for silicide is presumed to consist of the following four distinct steps:
1) Diffusion of oxidizing species through SiO,; 2) Reaction at the silicide/oxide interface; 3) Transport of silicon atoms relative to metal atoms in the silicide; and 4) Reaction at the polysilicon/silicide interface, which releases silicon v frorn the polysilicon substrate.
As above, the silicide is oxidized by reacting oxidizing species being in the reactor and silicon atoms in the silicide, and therefore the silicon oxide is formed on the surface of the silicide layer. Here, the silicon atoms wasted in the silicide during the oxidation are replaced by silicon atoms released from the polysilicon. As the oxidation reaction continues, the silicon oxide formed on the silicide continues to thicken.
Meanwhile, the oxidation reaction occurs at the silicide/silicon oxide interface all the time in accordance with diffusion of oxidizing species through silicon oxide.
FIG. 2 of the accompanying drawings is a sectional view showing a semiconductor device including a polycide structure fabricated by conventional technology.
Referring to FIG.2, a polycide structure consisting of polysilicon layer 13 and silicide layer 14 is formed on a gate oxide 12 which is formed on a semiconductor substrate 11. Then, silicon oxide layer 15 is formed on the whole surface of Polycide and semiconductor substrate 11, by an oxidation process of silicide according to the conventional technology shown in FIGA.
However, by the conventional process chained with the dry oxidation and wet oxidation, hydrogen gas during the wet oxidation accelerates the oxidation of silicide continuously. As a result, as shown in FIG.2, silicon of the polysilicon layer 13 is over-consumed partially, and therefore a structural -p defect occurs in the polysilicon and silicide. In view of this defect, the value of the threshold voltage of a MOS transistor cannot to be maintained constantly. Therefore, this structural defect deteriorates the reliability and productivity of a semiconductor device.
An object of a first aspect of this invention, to solve the problems of the conventional technology, is to provide a method of manufacturing the semiconductor device formed by oxidizing the silicide without the occurrence of structural defects.
An object of a second aspect of this invention is to provide a method of oxidizing the silicide in a polycide structure.
According to the first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps offorming a polycide structure on a semiconductor substrate by forming a gate insulating layer, a first conductive layer containing silicon, and a silicide layer in order; and forming a silicon oxide on the whole surface of the resultant structure by dry oxidation in an oxygen and hydrogen chloride gas atmosphere.
According to a second aspect of the present invention, there is provided a method of oxidizing a silicide of the polycide structure, comprising the steps of: loading a wafer which has a polycide structure formed by forming a gate -v 7 insulating layer, a first conductive layer containing silicon, and a silicide layer in order, in a reactor at a first temperature state; first annealing in a nitrogen gas atmosphere after ramping the temperature of reactor up to a second temperature state; dry oxidizing the silicide layer in an oxygen and hydrogen chloride gas atmosphere, second annealing in a nitrogen gas atmosphere after turning off the oxygen and hydrogen chloride gas; and unloading the resultant structure from the reactor after ramping the temperature of reactor down to a third temperature state.
According to this invention, during the silicide oxidation process, the oxygen and hydrogen chloride gas oxidizes the silicide stably, thereby to maintain a uniform amount of consumed silicon. Therefore, the structure defect which tends to be formed on the surface of the first conductive layer is prevented.
Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a schematic diagram showing an oxidation process of silicide according to conventional technology; FIG. 2 is a cross-sectional view of a semiconductor device fabricated by conventional technology; FIG. 3 is a scheinatic diagram showing an oxidation process of silicide .P 8 according to an embodiment of the present invention; and FIG. 4 is a cross-sectional view of a semiconductor device according to an embodiment of the present invention.
Referring to FIG.4 showing a semiconductor device fabricated according to an embodiment of the present invention, a polycide structure is formed over a semiconductor substrate 21 as a gate electrode or interconnection layer. The polycide structure is constructed by forming a gate oxide 22, the first conductive layer 23 containing silicon, and a silicide layer 24 in order. Then, a silicon oxide layer 25 is formed on the whole surface of the resultant structure. As the first conductive layer 23, polysilicon or single crystal silicon can be used.
A method of manufacturing a semiconductor device and oxidizing a silicide according to an embodiment of the present invention will be described as follows with reference to FIGS. 3 and 4.
As shown in FIG.4, at first, a gate oxide 22 and the first conductive layer 23 containing a polysilicon or single crystal silicon are stacked on a semiconductor substrate 21 in order. Next, a silicide layer 24 is formed on first conductive layer 23 according to a conventional method, such as, for example, direct metallurgical reaction, co-evaporation, sputter deposition (co- 9 sputtering and sputtering from composite targets, chemical vapour deposition 1 of silicides), and then patterned, thereby to form a gate electrode or an interconnection layer as a polycide structure.
Next, a wafer on which the polycide structure is formed is loaded in a reactor.
Referring to FIG.3, the reactor is in a nitrogen gas atmosphere between a certain temperature range, for example 650 10 11 C. At first, the temperature of the reactor is slowly ramped up to a certain high temperature (for example, 900 20"C) in a nitrogen gas atmosphere for approximately 25 minutes. Next, the wafer is annealed firstly in the same temperature and gas atmosphere condition for a certain time (for example, 30 minutes).
Then, the wafer is oxidized in a dry oxygen and hydrogen chloride gas atmosphere at the same temperature for a certain time (for example, 62 minutes), and thereby a silicon oxide layer 25 is formed on the silicide layer 24. Here,the nitrogen gas is turned off. At this time, the oxygen and hydrogen chloride gas as oxidizing species oxidize the silicide stably, thereby to maintain the amount of consumed silicon to be uniform. Of course, during the oxidation process the silicon oxide 25 is formed on a sidewall of the polycide and a exposed surface of the semiconductor substrate 21.
Next, the wafer is annealed secondarily in the same temperature for certain time (for example 15 minutes) in a nitrogen gas atmosphere with oxygen and hydrogen chloride gas turned off. Next, the wafer is unloaded is from the reactor after ramping down the temperature in the reactor slowly (for example, to the temperature range 650 10"C for approximately 90 minutes).
According to the present invention as shown in the above-described embodiment, during the silicide oxidation, the oxygen and hydrogen chloride gas (as oxidizing species) oxidizes the silicide stably, to thereby maintain a uniform amount of consumed silicon. Therefore, the structure defect which tends to be formed on the surface of the first conductive layer, and as occurs in the conventional technology, is prevented.
Therefore, the threshold voltage of a MOS transistor and the resistivity of the interconnection can be maintained constantly. Therefore, the reliability and productivity of a semiconductor device are improved.
While the present invention has been particularly shown and described with reference to particular embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be effected therein without departing from the scope of the invention.
.P 11

Claims (7)

CLAIMS:
1. A method for manufacturing a semiconductor device comprising the steps of:
forming a polycide structure on a semiconductor substrate by forming a gate insulating layer, a conductive layer containing silicon, and a silicide layer in order; and forming a silicon oxide on the whole surface of the resultant structure by dry oxidation in an oxygen and hydrogen chloride gas atmosphere.
2. A method for manufacturing a semiconductor device as defined in claim 1, wherein said conductive layer comprises a polysilicon.
3. A method for oxidizing a silicide of the polycide structure comprising the steps of.
loading a wafer which has a polycide structure formed by forming a gate insulating layer, a conductive layer containing silicon, and a silicide layer in order, in a reactor at a first temperature state; first annealing in a nitrogen gas atmosphere after ramping the temperature of reactor up to a second temperature state; dry oxidizing the silicide layer in an oxygen and hydrogen chloride gas atmosphere; second annealing in a nitrogen gas atmosphere after turning off the oxygen and hydrogen chloride gas; and unloading the resultant structure from the reactor after ramping the 12 temperature of reactor down to a third temperature state.
4. A method for oxidizing a silicide of the polycide structure as defined in claim 3, wherein the range of said first temperature state is 650 10 C.
5. A method for oxidizing a silicide of the polycide structure as defined in claim 3 or 4, wherein the range of said second temperature state is 900 20C
6. A method for manufacturing a semiconductor device substantially as hereinbefore described with reference to Figures 3 and 4 of the accompanying drawings.
7. A semiconductor device manufactured according to the method of any preceding claim.
1
GB9319730A 1992-09-26 1993-09-24 Manufacturing method of a semiconductor device Withdrawn GB2271467A (en)

Applications Claiming Priority (1)

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KR920017608 1992-09-26

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GB2271467A true GB2271467A (en) 1994-04-13

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CN (1) CN1087446A (en)
DE (1) DE4332605A1 (en)
GB (1) GB2271467A (en)
IT (1) IT1272674B (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004172259A (en) 2002-11-19 2004-06-17 Oki Electric Ind Co Ltd Method for manufacturing semiconductor element
KR100650858B1 (en) * 2005-12-23 2006-11-28 주식회사 하이닉스반도체 Method of manufacturing a flash memory device
JP5029257B2 (en) * 2007-01-17 2012-09-19 東京エレクトロン株式会社 Mounting table structure and processing device
CN104810263B (en) * 2014-01-24 2018-11-20 北大方正集团有限公司 The manufacturing method of gate oxide

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4139658A (en) * 1976-06-23 1979-02-13 Rca Corp. Process for manufacturing a radiation hardened oxide
EP0087581A1 (en) * 1982-02-22 1983-09-07 Siemens Aktiengesellschaft Method of making silicon oxide layers

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4139658A (en) * 1976-06-23 1979-02-13 Rca Corp. Process for manufacturing a radiation hardened oxide
EP0087581A1 (en) * 1982-02-22 1983-09-07 Siemens Aktiengesellschaft Method of making silicon oxide layers

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Publication number Publication date
DE4332605A1 (en) 1994-03-31
ITMI932044A0 (en) 1993-09-24
JPH06209049A (en) 1994-07-26
IT1272674B (en) 1997-06-26
GB9319730D0 (en) 1993-11-10
CN1087446A (en) 1994-06-01
ITMI932044A1 (en) 1995-03-24

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