JPH05114580A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To provide a method capable of selectively growing tungsten while preventing the oxygen on the surface or an insulating layer comprising a silicon oxide from being sputtered to be slicified when a pollutant layer adhering to the bottom surface of an aperture of the insulating layer is to be removed by a sputtering process. CONSTITUTION:A specimen wherein an insulating layer 3 comprising a silicon oxide having an aperture 4 is formed n a conductive layer or a semiconductor layer 2 is irradiated with neutral beams 6 of a rare gas to remove a pollutant layer 5 adhering to the bottom surface of the aperture 4 and then tungsten 8 is selectively grown on the part exposed in the aperture 4 of this conductive layer or the semiconductor layer 2 by vapor growth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of manufacturing a semiconductor device characterized by a tungsten selective vapor deposition method.

[0002]

2. Description of the Related Art Tungsten is selectively vapor-deposited in an opening of a conductor layer on a substrate such as a semiconductor or an insulating layer made of silicon oxide formed on the semiconductor layer to form, for example, interlayer connection. When forming a conductor for obtaining, for some reason, insulating fluoride, carbide,
A contaminant layer such as an oxide or a mixture thereof may be deposited, so that tungsten grows non-uniformly while avoiding this contaminant layer, so that this opening cannot be completely filled with tungsten and the electrical resistance increases. However, there is a problem that mechanical stability deteriorates.

Conventionally, in order to solve this problem, it has been considered that after forming an opening in an insulating layer made of silicon oxide, Ar sputtering is performed to physically remove the contaminated layer.

FIG. 6 is a process explanatory view of a conventional semiconductor device manufacturing method. In this figure, 51 is a semiconductor substrate,
52 is an aluminum wiring layer, 53 is a PSG insulating layer, 54 is an opening, 55 is a contaminated layer, 56 is Ar ions, and 57 is WF ₆ +.
H ₂ and 58 are siliconized layers, 59 is a connection plug made of tungsten, and 60 is a tungsten layer.

A conventional method of manufacturing a semiconductor device will be described with reference to the process explanatory drawings. First step (see FIG. 6A) PS is formed by CVD or the like on an aluminum wiring layer 52 provided on a semiconductor substrate 51 on which a semiconductor integrated circuit or the like is formed.
A G insulating layer 53 is deposited and an opening 54 is formed by a photolithography technique. On the bottom surface of the opening 54, although the cause is not always clear, the contaminated layer 5 of insulating silicon fluoride, carbide, oxide, or a mixture thereof is used.
5 may be formed.

Second step (see FIG. 6 (B)) A sample having this structure is set in an ion sputtering apparatus, and A
The contamination layer 55 on the bottom surface of the opening 54 is removed by sputtering with r ions 56.

Third step (see FIG. 1C) The sample formed in the previous step is set in a selective vapor phase growth apparatus, and the temperature of the substrate is kept at 450 ° C. and WF ₆ +
Pour H ₂ 57 and set the pressure to 60 torr
Selective vapor deposition of tungsten (W) is performed on the Al wiring layer 52 in the opening 54 of the insulating layer 53.

Fourth Step (Refer to FIG. 6D) By the previous step, tungsten is deposited in the opening 54 of the PSG insulating layer 53, and the connection plug 59 made of tungsten is formed in the Al wiring layer.

[0009]

However, when the contaminated layer 55 is removed by the sputtering with the Ar ions 56, the oxygen on the surface of the PSG insulating layer 53, which is the insulating layer, is selectively sputtered and the siliconized layer 58 is formed. Then, P is deposited on the tungsten by selective vapor deposition.
Even if an attempt is made to bury it in the opening of the SG insulating layer 53, the tungsten layer 60 grows on the surface of the siliconized insulating layer 53 around the connection plug 59 made of tungsten, and perfect selective growth cannot be performed. there were.

According to the present invention, when the contamination layer attached to the bottom surface of the opening of the insulating layer made of silicon oxide is removed by the sputtering method, oxygen on the surface of the insulating layer having silicon oxide is selectively sputtered. It is an object of the present invention to provide a method of manufacturing a semiconductor device, which can prevent silicon from being turned into silicon and selectively grow tungsten.

[0011]

In a method of manufacturing a semiconductor device according to the present invention, a sample in which an insulating layer made of silicon oxide having an opening is formed on a conductor layer or a semiconductor layer is used in a rare gas. Of the contaminated layer adhering to the bottom surface of the opening by irradiating a conductive beam, and then selectively depositing tungsten on the exposed portion of the conductor layer or the semiconductor layer in the opening by vapor phase epitaxy. Adopted a process to grow into.

At this time, the contamination layer adhering to the bottom surface of the opening of the insulating layer made of silicon oxide is removed by irradiating a neutral beam of a rare gas, and then the insulating layer made of silicon oxide is removed. The surface of the layer is ion-sputtered with a rare gas to remove the deteriorated layer caused by the neutral beam irradiation of the rare gas, and then the vapor phase is exposed on the exposed portion of the conductor layer or the semiconductor layer in the opening. A process of selectively growing tungsten by the growth method was adopted.

[0013]

When the contaminant layer adhering to the bottom surface of the opening of the insulating layer made of silicon oxide is removed by irradiating a neutral beam of a rare gas as in the present invention, the insulating layer made of silicon oxide is removed. Oxygen on the surface of is not selectively sputtered, and then tungsten can be selectively grown on the bottom surface of the opening.

Further, when the contamination layer attached to the bottom surface of the opening of the insulating layer made of silicon oxide as described above is removed by irradiating the neutral beam of the rare gas, the high energy neutral beam is used. Irradiation forms a roughened deteriorated layer on the surface of the insulating layer, and in the subsequent selective growth of tungsten, tungsten may be deposited in a lump form on the surface of the insulating layer, which hinders selective growth. When the altered layer is removed by irradiating rare gas ions and sputtering, tungsten can be selectively grown.

The reason why the above phenomenon occurs and the reason why it is solved by the present invention have not yet been clarified, but they have been experimentally confirmed by the inventors.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1A to 1C are process diagrams of a method of manufacturing a semiconductor device according to the first embodiment. In this figure, 1 is a semiconductor substrate, 2 is an aluminum wiring layer, 3 is a PSG insulating layer, 4 is an opening, 5 is a contamination layer, 6 is a neutral gas neutral beam, and 7 is WF _6.
+ H ₂ and 8 are connection plugs made of tungsten.

A method of manufacturing the semiconductor device of the first embodiment will be described with reference to the process explanatory drawings. First step (see FIG. 1A) A PSG insulating layer 3 is deposited by CVD or the like on an aluminum wiring layer 2 provided on a semiconductor substrate 1 on which a semiconductor integrated circuit or the like is formed, and a photolithography technique is used. The opening 4 is formed. For some reason on the bottom of this opening,
A contaminant layer 5 of insulating silicon fluoride, carbide, oxide or a mixture thereof is formed.

Second step (see FIG. 1B) The sample formed in the previous step is set in the neutral beam irradiation apparatus, Ar is flown, the pressure is kept at 5 × 10 ⁻⁴ torr, and the frequency is 2.45 GHz. 0.9 kW of microwave is input to irradiate the PSG insulating layer 3 with Ar neutral beam 6. According to this step, the contamination layer 5 can be completely removed without losing oxygen from the surface of the PSG insulating layer 3 by selective sputtering.

Third step (see FIG. 1C) This sample is set in a selective vapor phase growth apparatus, WF ₆ + H ₂ 7 is flown while the substrate temperature is kept at 450 ° C., and the pressure is set to 60 torr. A in the opening 4 of the PSG insulating layer 3
Selective vapor deposition of tungsten (W) is performed on the 1 wiring layer 2.

Fourth Step (Refer to FIG. 1D) In the previous step, tungsten is deposited in the opening 4 of the PSG insulating layer 3 but not on the surface of the PSG insulating layer 3 and on the Al wiring layer. Connection plug 8 made of tungsten
Can be formed.

FIG. 2 is an explanatory view of the neutral beam irradiation device used in the present invention. In this figure, 11 is an ion source, 12 is a gas supply pipe, 13 is a waveguide, 14 is a solenoid magnet, 15 is a multi-aperture, 16 is a vacuum chamber, 17 is an exhaust pipe, 18 is a retarding grid, and 19 is a susceptor. Is.

In this neutral beam irradiation device, the rare gas supplied from the gas supply pipe 12 is acted on by the action of the microwave incident from the waveguide 13 and the magnetic field formed by the solenoid magnet 14 in the ion source 11. Cyclotron resonance causes strong ionization, and the accelerating potential of the multi-aperture 15 accelerates and draws out ions into the vacuum chamber 16 exhausted by the exhaust pipe 17. The ions are neutralized in the process of passing through the vacuum chamber 16 and then the retarding grid. The non-neutralized beam is blocked by 18 and only the neutral beam is irradiated onto the susceptor 19.

FIG. 3 is an explanatory view of the selective vapor phase growth apparatus used in the present invention. In this figure, 21 is a reaction chamber, 22 is a reaction gas supply pipe, 23 is an exhaust pipe, 24 is an electrode, 25 is a susceptor, 26 is a sample, 27 is a quartz plate, 2
Reference numeral 8 is an infrared lamp for heating.

In this selective vapor phase growth apparatus, after the reaction chamber 21 is exhausted from the exhaust pipe 23, the reaction gas supply pipe 22
The reaction gas is supplied from the above, the sample 26 mounted on the susceptor 25 is heated to a predetermined temperature by the infrared lamp 28 for heating through the quartz plate 27, and a high frequency voltage is applied between the electrode 24 and the susceptor 25. The reaction gas is decomposed and deposited on the sample 26.

In the above embodiments, the wiring layer for selectively growing tungsten is described as an Al wiring, but the selective growth can be achieved even if the wiring layer is changed to a silicon layer or a conductor layer made of W, Ti, TiN or TiW. The results were similar.

In the above embodiments, the insulating layer is the PSG insulating layer, but other silicon oxide type insulating layers such as SiO layer, BPSG layer and BS are used.
Even if the layer was changed to the G layer, the results regarding the selective growth were the same.

Further, although Ar gas was used as the rare gas in the above-mentioned embodiment, it was used as He, Ne, K.
The results were the same even when r and Xe were changed.

(Second Embodiment) FIG. 4 is a process explanatory view of a method for manufacturing a semiconductor device according to a second embodiment. In this figure, 31 is a semiconductor substrate, 32 is an aluminum wiring layer, and 33 is P.
SG insulating layer, 34 is an opening, 35 is a contaminated layer, 36 is a neutral beam of a rare gas, 37 is an altered layer, 38 is a rare gas ion, 3
Reference numeral 9 is a connection plug made of WF ₆ + H ₂ and 40 is made of tungsten.

A method of manufacturing the semiconductor device of the second embodiment will be described with reference to the process explanatory drawings. First step (see FIG. 4A) PS is formed by CVD or the like on an aluminum wiring layer 32 provided on a semiconductor substrate 31 on which a semiconductor integrated circuit or the like is formed.
After depositing the G insulating layer 33, an opening 34 is formed at a predetermined place. A contamination layer 5 of insulating silicon fluoride or the like is formed on the bottom surface of the opening for some reason.

Second step (see FIG. 4 (B)) A sample having this structure is set in a neutral beam irradiation apparatus and Ar
To maintain the pressure at 5 × 10 ⁻⁴ torr and the frequency 2.
A 45 GHz microwave is input at 0.9 kW to irradiate the neutral beam 6 of Ar on the PSG insulating layer 33. By this step, the contamination layer 35 formed on the bottom surface of the opening 34 of the PSG insulating layer 33 is removed, but this beam is injected into the surface of the PSG insulating layer 33 by the high-energy neutral beam 36 to roughen the surface. When the transformed layer 37 that has been turned into a thin film is formed and then the selective growth of tungsten is performed, tungsten is deposited in a lump form on the surface of the insulating layer, and the selective growth is hindered.

Third step (see FIG. 4C) In this step, the sample formed in the previous step is set in an ion sputtering apparatus, and Ar ions 3 are formed on the surface thereof.
The altered layer 37 is removed by irradiating 8 and performing sputtering. During the sputtering with the rare gas ions 38, the altered layer 37 is more likely to be sputtered than the PSG insulating layer 33. Therefore, it is easy to control so that excessive sputtering does not cause selective sputtering of oxygen on the surface of the PSG insulating layer 33. Is.

Fourth step (see FIG. 4D) This sample was set in a selective vapor phase growth apparatus, WF ₆ + H ₂ 39 was flown while the substrate temperature was kept at 450 ° C., and the pressure was set to 60 torr. Then, the opening 34 of the PSG insulating layer 33 is formed.
Selective vapor deposition of tungsten is performed on the Al wiring layer 32 inside.

By this step, tungsten is deposited in the opening 34 of the PSG insulating layer 33 with high selectivity, and the connection plug 40 made of tungsten is formed in the Al wiring layer 32. The neutral beam irradiation apparatus and the selective vapor phase growth apparatus used in this embodiment are the same as those used in the first embodiment.

FIG. 5 is an explanatory diagram of an ion sputtering apparatus used in the present invention. In this figure, 41 is a reaction chamber, 42 is a gas supply pipe, 43 is an exhaust pipe, 44 is an electrode,
Reference numeral 45 is a susceptor, 46 is a sample, and 47 is a bias power supply.

In this ion sputtering apparatus, the gas supply pipe 42 is placed in the reaction chamber 41 exhausted by the exhaust pipe 43.
A sputtering gas is supplied through the electrodes, and the sputtering gas is ionized by applying a voltage between the electrode 44 and the susceptor 45 on which the sample 46 is placed to generate plasma,
The sample 45 is irradiated with the ions. The high frequency bias power source 47 is equipped to adjust the state of plasma.

In this embodiment, the wiring layer for selectively growing tungsten is a silicon layer or W, Ti, TiN, T.
The insulating layer may be changed to a conductive layer made of iW, and the insulating layer may be another silicon oxide type insulating layer, for example, a SiO layer or BP.
The SG layer and the BSG layer can be changed, and the rare gas forming the neutral beam can be changed to He, Ne, Kr, and Xe.

In the present embodiment, an example was described in which Ar was used as the gas used for ion sputtering for removing the altered layer, but He, Ne, K was used instead.
It is also possible to use a gas selected from r and Xe.

[0038]

As described above, according to the present invention,
The contamination layer adhering to the bottom surface of the opening of the insulating layer made of silicon oxide can be removed without degrading the surface of the insulating layer, and subsequent selective growth of tungsten can be carried out without trouble. In a semiconductor integrated circuit device or the like, it is possible to easily obtain a stable interlayer connection conductor with low resistance.

[Brief description of drawings]

FIG. 1 is a process explanatory view of a method for manufacturing a semiconductor device according to a first embodiment.

FIG. 2 is an explanatory diagram of a neutral beam irradiation device used in the present invention.

FIG. 3 is an explanatory view of a selective vapor phase growth apparatus used in the present invention.

FIG. 4 is a process explanatory view of the method for manufacturing the semiconductor device of the second embodiment.

FIG. 5 is an explanatory diagram of an ion sputtering apparatus used in the present invention.

FIG. 6 is a process explanatory diagram of a conventional method for manufacturing a semiconductor device.

[Explanation of symbols] 1 semiconductor substrate 2 aluminum wiring layer 3 PSG insulating layer 4 opening 5 contamination layer 6 neutral beam of rare gas 7 WF ₆ + H ₂ 8 connection plug made of tungsten

Claims (7)

[Claims] 1. A sample in which an insulating layer made of silicon oxide having an opening is formed on a conductor layer or a semiconductor layer is irradiated with a neutral beam of a rare gas to adhere to the bottom surface of the opening. A method of manufacturing a semiconductor device, comprising the step of selectively growing tungsten on a portion of the conductor layer or the semiconductor layer exposed in the opening by vapor deposition after removing the contaminated layer. .. 2. The conductor layer is W, Al, Ti, TiN, T
The method for manufacturing a semiconductor device according to claim 1, wherein the layer is a layer selected from iW. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the semiconductor layer is a silicon layer. 4. The insulating layer made of silicon oxide is Si
The method for manufacturing a semiconductor device according to claim 1, wherein the method is selected from O ₂ , BPSG, PSG, and BSG. 5. The neutral beam is He, Ne, Ar or K.
2. The method of manufacturing a semiconductor device according to claim 1, wherein the gas is selected from gases selected from r and Xe. 6. The contamination layer adhering to the bottom surface of the opening of the insulating layer made of silicon oxide is removed by irradiating the neutral beam of the rare gas, and then the surface of the insulating layer is ionized with the rare gas. After removing the deteriorated layer generated by the irradiation of the rare gas with the neutral beam by sputtering, tungsten is selectively deposited on the exposed portion of the conductor layer or the semiconductor layer in the opening by vapor phase epitaxy. The method for manufacturing a semiconductor device according to claim 1, further comprising a step of growing. 7. The method of manufacturing a semiconductor device according to claim 6, wherein the gas used in the ion sputtering with the rare gas is selected from He, Ne, Ar, Kr, and Xe.