KR20090022788A - Method of manufacturing semiconductor device - Google Patents

Method of manufacturing semiconductor device Download PDF

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Publication number
KR20090022788A
KR20090022788A KR1020070088411A KR20070088411A KR20090022788A KR 20090022788 A KR20090022788 A KR 20090022788A KR 1020070088411 A KR1020070088411 A KR 1020070088411A KR 20070088411 A KR20070088411 A KR 20070088411A KR 20090022788 A KR20090022788 A KR 20090022788A
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KR
South Korea
Prior art keywords
gate
film
semiconductor substrate
semiconductor device
metal
Prior art date
Application number
KR1020070088411A
Other languages
Korean (ko)
Inventor
김준기
하가영
Original Assignee
주식회사 하이닉스반도체
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Application filed by 주식회사 하이닉스반도체 filed Critical 주식회사 하이닉스반도체
Priority to KR1020070088411A priority Critical patent/KR20090022788A/en
Publication of KR20090022788A publication Critical patent/KR20090022788A/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
    • H01L21/02227—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process
    • H01L21/0223—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate
    • H01L21/02233—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer
    • H01L21/02236—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer group IV semiconductor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/28—Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268
    • H01L21/28008—Making conductor-insulator-semiconductor electrodes
    • H01L21/28017—Making conductor-insulator-semiconductor electrodes the insulator being formed after the semiconductor body, the semiconductor being silicon
    • H01L21/28158—Making the insulator
    • H01L21/28167—Making the insulator on single crystalline silicon, e.g. using a liquid, i.e. chemical oxidation
    • H01L21/28211—Making the insulator on single crystalline silicon, e.g. using a liquid, i.e. chemical oxidation in a gaseous ambient using an oxygen or a water vapour, e.g. RTO, possibly through a layer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/40—Electrodes ; Multistep manufacturing processes therefor
    • H01L29/43—Electrodes ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
    • H01L29/49—Metal-insulator-semiconductor electrodes, e.g. gates of MOSFET
    • H01L29/4916—Metal-insulator-semiconductor electrodes, e.g. gates of MOSFET the conductor material next to the insulator being a silicon layer, e.g. polysilicon doped with boron, phosphorus or nitrogen
    • H01L29/4925—Metal-insulator-semiconductor electrodes, e.g. gates of MOSFET the conductor material next to the insulator being a silicon layer, e.g. polysilicon doped with boron, phosphorus or nitrogen with a multiple layer structure, e.g. several silicon layers with different crystal structure or grain arrangement

Abstract

A method of manufacturing the semiconductor device is provided to oxidize the polysilicon film part of the gate contacting with the semiconductor substrate by the radical type and to effectively improve the selective oxidation process of the metal gate. The gate insulating layer(202), the polysilicon layer(204) and metal layer(206) are successively formed on the semiconductor substrate(200). The gate(210) is formed on the semiconductor substrate by etching the metal layer, the polysilicon layer and gate insulating layer. The selective oxidation is performed to the gate by using the radical type. The metal layer can be formed with selected one among W, Mo, and Ta and Ru.

Description

Manufacturing method of semiconductor device {METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for manufacturing a semiconductor device capable of effectively improving a selective oxidation process of a metal gate.

In general, a gate of a semiconductor device includes a gate conductive film made of an oxide film and a polysilicon film, and a laminated film of a protective film formed on the gate conductive film. This is because the polysilicon film satisfies physical properties required as a gate such as high melting point, ease of thin film formation, ease of line pattern, stability to an oxidizing atmosphere, and flat surface formation.

However, in accordance with the recent trend of high integration of semiconductor devices, as the design rule decreases, the channel length becomes smaller than the gate width when the width of the gate electrode is 0.35 μm or less, thereby lowering the resistance. In order to form the gate having the gate conductive film, a metal gate structure composed of a laminated film of a polysilicon film and a metal film has been converted. Research is being actively conducted.

Hereinafter, a method of forming a gate to which a tungsten film is applied as the metal film will be briefly described.

First, a gate insulating film made of an oxide film is deposited on a semiconductor substrate having an isolation layer defining an active region, and then a polysilicon film and a tungsten film are sequentially deposited on the gate insulating film as a gate conductive film. A nitride film is deposited as a hard mask film on the film.

In this case, the tungsten film is usually deposited through CVD (Chemical Vapor Deposition) or PVD (Physical Vapor Deposition) method. Next, the hard mask layer, the gate conductive layer and the gate insulating layer are etched to form a metal gate on the semiconductor substrate.

Subsequently, an electric field is concentrated in the polysilicon film portion of the metal gate in contact with the semiconductor substrate to oxidize the sidewall of the gate to prevent the threshold voltage from decreasing. Through the oxidation process, defects on the semiconductor substrate generated by collision of ions during etching of the gate may be reduced, and the polysilicon layer may be alleviated.

However, in the case of the metal gate, in particular, the metal gate to which the tungsten film is applied, the tungsten film is oxidized before the polysilicon film portion of the semiconductor substrate and the metal gate in contact with the semiconductor substrate during the oxidation process performed in an oxygen atmosphere. Increasingly, defects are generated on semiconductor substrates, which create difficulties in further processing.

Accordingly, a selective oxidation process has been proposed in which the gate is oxidized in an oxygen and hydrogen atmosphere so that only the semiconductor substrate and the polysilicon layer portion contacting the semiconductor substrate and the tungsten layer are not oxidized during the oxidation process. This selective oxidation process is usually carried out by furnace or Rapid Thermal Annealing (RTA) method.

However, in the case of performing the selective oxidation process according to the above-described conventional technique, because the process temperature is high, the gate insulating film is deteriorated by the thermal stress of the hard mask film, and oxygen is diffused to the center of the gate where the oxidation reaction is not desired, so that the oxidation reaction is performed. This increases the thickness of the gate insulating film.

In order to prevent such a problem, a plasma may be generated in an atmosphere containing oxygen and hydrogen to perform a selective oxidation process, but in this case, oxygen ionized by the plasma potential existing between the semiconductor substrate and the plasma may be generated. Acceleration occurs toward the semiconductor substrate to cause defects on the semiconductor substrate, and oxidation of the semiconductor substrate proceeds at a faster rate than oxidation of the polysilicon film.

1 is a photograph of a semiconductor device showing a problem of the prior art. As shown, the thickness B of the oxide film formed on the semiconductor substrate is greater than the thickness A of the oxide film formed on the portion to be oxidized during the selective oxidation process using the plasma, that is, the polysilicon film portion in contact with the semiconductor substrate. You can see that it is thicker. For this reason, much time is consumed in order to fully oxidize the polysilicon film sidewall of the metal gate to be oxidized, and an unnecessary thick oxide film is formed on the semiconductor substrate.

The present invention provides a method of manufacturing a semiconductor device that can effectively improve the selective oxidation process of the metal gate.

In addition, the present invention provides a method of manufacturing a semiconductor device that can improve the characteristics and reliability of the device by improving the characteristics of the metal gate.

A method of manufacturing a semiconductor device according to the present invention includes the steps of sequentially forming a gate insulating film, a polysilicon film and a metal film on a semiconductor substrate; Etching the metal layer, the polysilicon layer, and the gate insulating layer to form a gate on the semiconductor substrate; And performing a selective oxidation process on the gate using a radical mode.

Here, the metal film is formed of any one selected from W, Mo, Ta, and Ru.

The radical oxidation is performed by generating radicals using an electric field or microwave.

The radical oxidation is carried out at a temperature of 300 to 800 ℃.

The radical oxidation is carried out in an oxygen and hydrogen atmosphere.

As described above, the present invention can effectively improve the selective oxidation of the metal gate by radically oxidizing the polysilicon layer of the gate in contact with the semiconductor substrate, thereby changing the threshold voltage of the gate. It is possible to improve the characteristics of the gate, such as to prevent.

Therefore, the present invention can improve device characteristics and reliability by improving the characteristics of the gate.

The present invention oxidizes the polysilicon layer of the gate in contact with the semiconductor substrate in order to prevent the threshold voltage change of the gate, and the oxidation is performed by a selective oxidation process through a radical method in an oxygen and hydrogen atmosphere.

In this way, not only oxidation is possible in a low temperature atmosphere, but also the edge portion of the lower portion of the gate in contact with the semiconductor substrate can be effectively oxidized in a relatively fast time, so that an electric field is concentrated at the edge portion, thereby lowering the threshold voltage of the gate. Can be prevented.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

2A to 2D are cross-sectional views of processes for describing a method of manufacturing a semiconductor device according to the present invention.

Referring to FIG. 2A, a device isolation layer is formed by etching the device isolation region of the semiconductor substrate 200 having the active region and the device isolation region to form a trench, and then filling the trench with an insulating layer to define the active region. No).

Next, the gate insulating film 202, the polysilicon film 204, the metal film 206, and the hard mask film 208 are sequentially formed on the semiconductor substrate 200 including the device isolation film. The gate insulating film 202 is formed of an oxide film, the metal film 206 is formed of any one selected from W, Mo, Ta, and Ru, preferably, W, and the hard mask film 208 is formed of a nitride film. .

Referring to FIG. 2B, the hard mask layer 208, the metal layer 206, the polysilicon layer 204, and the gate insulating layer 202 are etched through a known photo process to etch the semiconductor substrate 200. A metal gate 210 is formed on it.

Referring to FIG. 2C, a selective oxidation process is performed on the resultant of the semiconductor substrate 200 on which the metal gate 210 is formed at a temperature of about 300 ° C. to 800 ° C. in a radical manner, so that the semiconductor substrate 200 and the metal contacting the substrate 200 may be formed. An oxide film 212 is formed by oxidizing the sidewall portion of the polysilicon film 204 of the gate 210.

In detail, after injecting oxygen and hydrogen into the chamber on which the semiconductor substrate 200 on which the metal gate 210 is formed is injected to generate a plasma, when the ions in the plasma are induced to the outside by using an electric field or microwave, Radicals with high energy states are generated.

In other words, the ions in the plasma are removed by the collision with the electrons, and radicals that are not ionized but have an electrically high energy state are formed. These radicals are highly reactive due to their high energy state, and as a result, the selective oxidation process can be performed even at low temperatures.

In addition, in the case of the radical oxidation, since the reactants are not directional as in the conventional case, the metal gate 200 in contact with the semiconductor substrate 200 together with the sidewall portion of the polysilicon film 204 of the metal gate 210. It can be effectively oxidized up to the edge of).

Accordingly, the present invention can perform a selective oxidation process without generating a collision defect on the semiconductor substrate 200 at a low temperature at a fast time by performing a selective oxidation process using a radical method, and also, the selective oxidation Through the process, the concentration of the electric field on the corner portion of the metal gate 210 may be suppressed to prevent the threshold voltage of the metal gate 210 from changing.

Referring to FIG. 2D, after depositing an insulating film on the surface of the metal gate 210 including the oxide film 212, the insulating film is etched to form a spacer 214 on the sidewall of the metal gate 210 including the oxide film 212. To form. The spacer 214 is preferably formed of a nitride film or an oxide film.

Then, an impurity ion implantation process is performed on the resultant of the semiconductor substrate 200 on which the spacers 214 are formed to form source and drain regions 216 in the semiconductor substrate 200 on both sides of the metal gate 210. do.

Thereafter, although not shown, a series of subsequent known processes are sequentially performed to complete the semiconductor device according to the embodiment of the present invention.

3 is a graph showing a range of selective oxidation conditions according to the present invention.

Line A in the graph shown is a condition under which a reaction of Si + 2H 2 O → SiO 2 + 2H 2 takes place, and above the line A, oxidation of the polysilicon film occurs as in this scheme. Line B is a condition in which the reaction of W + 3H 2 O → WO 3 + 3H 2 occurs, and line C is a condition in which the reaction of W + 2H 2 O → WO 2 + 2H 2 occurs, and conditions of line B and C are higher. The oxidation of tungsten film takes place as in this scheme.

Therefore, the selective oxidation process in which only the polysilicon film is oxidized without oxidation of the tungsten film can be effectively performed in the condition range between the A and C lines shown in the graph.

The present invention improves the selective oxidation process by performing a selective oxidation process of oxidizing the polysilicon film sidewall of the metal gate using a radical method, thereby improving the corner portion of the metal gate in contact with the semiconductor substrate including the polysilicon film sidewall. It can be oxidized effectively.

Therefore, the present invention can prevent the electric field from being concentrated on the corner portion of the metal gate, thereby preventing the threshold voltage of the metal gate from fluctuating, thereby improving device characteristics and reliability including gate characteristics.

In addition, according to the present invention, by performing the selective oxidation process using the radical method in an oxygen and hydrogen atmosphere, it is possible to oxidize the polysilicon film at a low time at a low temperature, so that a defect occurs on the semiconductor substrate during the selective oxidation process. Can be prevented.

Hereinbefore, the present invention has been illustrated and described with reference to specific embodiments, but the present invention is not limited thereto, and the scope of the following claims is not limited to the spirit and scope of the present invention. It will be readily apparent to those skilled in the art that various modifications and variations can be made.

1 is a photograph of a semiconductor device showing the problems of the prior art.

2A to 2D are cross-sectional views of processes for describing a method of manufacturing a semiconductor device according to the present invention.

3 is a graph showing a range of selective oxidation conditions in accordance with the present invention.

Explanation of symbols on the main parts of the drawings

200 semiconductor substrate 202 gate insulating film

204: polysilicon film 206: metal film

208: hard mask film 210: metal gate

212: oxide film 214: spacer

216 source and drain regions

Claims (5)

Sequentially forming a gate insulating film, a polysilicon film, and a metal film on the semiconductor substrate; Etching the metal layer, the polysilicon layer, and the gate insulating layer to form a gate on the semiconductor substrate; And Performing a selective oxidation process on the gate using a radical approach; Method of manufacturing a semiconductor device comprising a. The method of claim 1, The metal film is a method of manufacturing a semiconductor device, characterized in that formed by any one selected from W, Mo, Ta and Ru. The method of claim 1, The radical type oxidation is a method of manufacturing a semiconductor device, characterized in that performed by generating a radical using an electric field, or microwave. The method of claim 1, The radical type oxidation is a method for manufacturing a semiconductor device, characterized in that carried out at a temperature of 300 ~ 800 ℃. The method of claim 1, The radical type oxidation is a method of manufacturing a semiconductor device, characterized in that performed in oxygen and hydrogen atmosphere.
KR1020070088411A 2007-08-31 2007-08-31 Method of manufacturing semiconductor device KR20090022788A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020070088411A KR20090022788A (en) 2007-08-31 2007-08-31 Method of manufacturing semiconductor device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020070088411A KR20090022788A (en) 2007-08-31 2007-08-31 Method of manufacturing semiconductor device

Publications (1)

Publication Number Publication Date
KR20090022788A true KR20090022788A (en) 2009-03-04

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Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020070088411A KR20090022788A (en) 2007-08-31 2007-08-31 Method of manufacturing semiconductor device

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