Cleaning method of semiconductor manufacturing device

Abstract

This invention provides a cleaning method that uses a cleaning gas composition for a semiconductor manufacturing device, including a monofluorohalogen compound represented by XF (in which X is Cl, Br or I) as the main component, and provides a method for removing unwanted film, such as a Si-containing deposit, attached to the interior of the processing room or processing vessel after a processing operation without damaging the interior of the processing room or processing vessel using such monofluorohalogen compound.

Claims

1. A cleaning method that includes a process of removing an unwanted Si-containing deposit directly attached to a surface of an interior of a processing room or processing vessel without damaging the interior of the processing room or processing vessel after performing a processing operation in the interior of the processing room or processing vessel used for manufacturing a semiconductor device, the method comprising supplying, in that process of removing a Si-containing deposit without using a plasma, monofluorohalogen gas into the processing room or processing vessel to remove the Si-containing deposit, wherein: the monofluorohalogen gas is ClF; a material of the surface of the interior of the processing room or processing vessel consists of at least one selected from the group consisting of graphite (C), alumina (Al.sub.2O.sub.3) and aluminum nitride (AlN); the processing room or processing vessel has a temperature of 400° C. to 600° C. when the monofluorohalogen gas is supplied into the processing room or processing vessel; and the unwanted Si-containing deposit includes at least one of silicon dioxide (SiO.sub.2), silicon nitride (SiN), silicon carbide (SiC), polycrystalline silicon (Poly-Si), single crystal silicon, amorphous silicon (a-Si), silicon oxynitride (SiON), silicon carbonitride (SiCN), and silicon oxycarbonitride (SiOCN).

2. The method according to claim 1, wherein the ClF is diluted to an ClF concentration of 20 to 90 vol % against 100 vol % of the total amount of ClF and inert gas.

3. The method according to claim 1, wherein the unwanted Si-containing deposit includes at least one of silicon dioxide (SiO.sub.2) and polycrystalline silicon (Poly-Si), and wherein the etching rate of Poly-Si is 600 nm/min or higher, and the etching rate of SiO.sub.2 is 200 nm/min or higher.

4. The method according to claim 3, wherein the material of the surface of the interior of the processing room or processing vessel consists of graphite (C).

5. The method according to claim 3, wherein the material of the surface of the interior of the processing room or processing vessel consists of alumina (Al.sub.2O.sub.3).

6. The method according to claim 3, wherein the material of the surface of the interior of the processing room or processing vessel consists of aluminum nitride (AlN).

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows a schematic view of the thermal CVD device used in the Examples.

DESCRIPTION OF EMBODIMENTS

(2) The cleaning gas composition used in the cleaning method of the interior of the processing room or processing vessel of the semiconductor manufacturing device of the present invention includes monofluorohalogen compound represented by XF (wherein X is Cl, Br or I) as the main active component.

(3) The XF (wherein X is Cl, Br or I) used in the cleaning method of the present invention is preferably diluted by inert gas selected from N.sub.2, CO.sub.2, He, Ar, Ne, Kr, and Xe particularly when highly controllable cleaning is demanded. XF should preferably be diluted to an XF concentration of 10 to 90 vol % against 100 vol % of the total amount of XF and inert gas, and more preferably to 10 to 40 vol %. The role of the inert gas is to regulate excessive reaction by XF, and it effectively improves the controllability of cleaning. The area at which inert gas is added is the stage before introducing XF to the processing room or processing vessel, or in the processing room or processing vessel.

(4) The cleaning method of the present invention is useful when cleaning is performed at a high temperature of 400° C. or higher. The conventional cleaning gas was highly reactive, and damaged the interior of the processing room or processing vessel at a high temperature of 400° C. or higher.

(5) When introducing a cleaning gas composition and performing a cleaning operation of the interior of the processing room or processing vessel of the semiconductor manufacturing device in the cleaning method of the present invention, the interior of the processing room or processing vessel may be heated to 400° C. or higher and lower than 2000° C. to efficiently react the monofluorohalogen compound represented by XF (wherein X is Cl, Br or I) with the unwanted deposit attached to the interior of the processing room or processing vessel, which allows the processing room or processing vessel to be cleaned and solves the aforementioned problem.

(6) The temperature of the interior of the processing room or processing vessel is preferably heated to 400° C. or higher and lower than 1000° C., particularly 400° C. or higher and 800° C. or lower, and particularly 400° C. or higher and 600° C. or lower.

(7) When introducing a cleaning gas composition and performing a cleaning operation of the interior of the processing room or processing vessel of the semiconductor manufacturing device in the cleaning method of the present invention, the interior of the processing room or processing vessel may be adjusted to a pressure in a range of 0.001 to 760 Torr to efficiently react the monofluorohalogen compound represented by XF (wherein X is Cl, Br or I) with the unwanted deposit attached to the interior of the processing room or processing vessel, which allows the processing room or processing vessel to be cleaned. When a cleaning that does not damage the interior of the processing room or processing vessel of a semiconductor manufacturing device, or a highly controllable cleaning, is particularly desired, or when a compound with a relatively low vapor pressure is produced through the cleaning operation, the pressure of the interior of the processing room or processing vessel is preferably adjusted to a range of 0.001 to 300 Torr.

EXAMPLES

(8) The present invention is further described by Examples and Comparative Examples without being limited thereby.

(9) The following examples were performed by using the device shown in FIG. 1.

Example 1

(10) A Si wafer sample composed of a Si substrate being laminated with 100 nm of SiO.sub.2, the SiO.sub.2 layer being further laminated with 300 nm of polycrystalline silicon (Poly-Si), was placed inside the processing vessel of the heatable vacuum device, and ClF was applied as a monofluorohalogen compound. ClF was fed from the capturing vessel through the mass flow controller into the processing vessel at a flow rate of 100 sccm, and N.sub.2 was simultaneously fed as an inert gas to provide dilution at a flow rate of 400 sccm to adjust the ClF concentration to 20 vol %. The wafer sample was processed for 30 sec. by adjusting the device interior to a temperature of 400° C. and a pressure of 100 Torr. As a result, all the Poly-Si film and the SiO.sub.2 film were removed (etching rate of Poly-Si was 600 nm/min or higher, and the etching rate of SiO.sub.2 was 200 nm/min or higher), and no change was observed in the appearance of the Si substrate, and the weight change rate was −0.09%.

Example 2

(11) A Si wafer sample and processing device similar to Example 1 were used, and ClF was applied as the monofluorohalogen compound. ClF was fed from the capturing vessel through the mass flow controller into the processing vessel at a flow rate of 200 sccm, and N.sub.2 was simultaneously fed as an inert gas to provide dilution at a flow rate of 300 sccm to adjust the ClF concentration to 40 vol %. The wafer sample was processed for 30 sec. by adjusting the device interior to a temperature of 400° C. and a pressure of 100 Torr. As a result, all the Poly-Si film and the SiO.sub.2 film were removed (etching rate of Poly-Si was 600 nm/min or higher, and the etching rate of SiO.sub.2 was 200 nm/min or higher), and no change was observed in the appearance of the Si substrate, and the weight change rate was −0.06%.

Example 3

(12) A Si wafer sample and processing device similar to Example 1 were used, and ClF was applied as the monofluorohalogen compound. ClF was fed from the capturing vessel through the mass flow controller into the processing vessel at a flow rate of 50 sccm, and N.sub.2 was simultaneously fed as an inert gas to provide dilution at a flow rate of 450 sccm to adjust the ClF concentration to 10 vol %. The wafer sample was processed for 30 sec. by adjusting the device interior to a temperature of 400° C. and a pressure of 100 Torr. As a result, all the Poly-Si film and the SiO.sub.2 film were removed (etching rate of Poly-Si was 600 nm/min or higher, and the etching rate of SiO.sub.2 was 200 nm/min or higher), and no change was observed in the appearance of the Si substrate, and the weight change rate was −0.01%.

Example 4

(13) A Si wafer sample and processing device similar to Example 1 were used, and ClF was applied as the monofluorohalogen compound. ClF was fed from the capturing vessel through the mass flow controller into the processing vessel at a flow rate of 400 sccm, and N.sub.2 was simultaneously fed as an inert gas to provide dilution at a flow rate of 100 sccm to adjust the ClF concentration to 80 vol %. The wafer sample was processed for 30 sec. by adjusting the device interior to a temperature of 400° C. and a pressure of 100 Torr. As a result, all the Poly-Si film and the SiO.sub.2 film were removed (etching rate of Poly-Si was 600 nm/min or higher, and the etching rate of SiO.sub.2 was 200 nm/min or higher), and no change was observed in the appearance of the Si substrate, and the weight change rate was −0.17%.

Comparative Example 1

(14) A wafer sample similar to Example 1 was placed inside the processing vessel of the heatable vacuum device, and ClF.sub.3 was fed from the capturing vessel through the mass flow controller at a flow rate of 100 sccm, and N.sub.2 was simultaneously fed as an inert gas to provide dilution at a flow rate of 400 sccm to adjust the ClF.sub.3 concentration to 20 vol %. The wafer sample was processed for 30 sec. by setting the temperature to 400° C. and the pressure to 100 Torr. As a result, all the Poly-Si film and the SiO.sub.2 film were removed (etching rate of Poly-Si was 600 nm/min or higher, and the etching rate of SiO.sub.2 was 200 nm/min or higher), but the Si substrate was badly damaged, and the weight change rate was −2.40%.

Comparative Example 2

(15) A wafer sample similar to Example 1 was placed inside the processing vessel of the heatable vacuum device, and ClF.sub.3 was fed from the capturing vessel through the mass flow controller into the processing vessel at a flow rate of 200 sccm, and N.sub.2 was simultaneously fed as an inert gas to provide dilution at a flow rate of 300 sccm to adjust the ClF.sub.3 concentration to 40 vol %. The wafer sample was processed for 30 sec. at 400° C. and a pressure of 100 Torr. As a result, all the Poly-Si film and SiO.sub.2 film were removed (etching rate of Poly-Si was 600 nm/min or higher, and the etching rate of SiO.sub.2 was 200 nm/min or higher), but the Si substrate was badly damaged, and the weight change rate was −2.32%.

Comparative Example 3

(16) A wafer sample similar to Example 1 was placed inside the processing vessel of the heatable vacuum device, and ClF.sub.3 was fed from the capturing vessel through the mass flow controller at a flow rate of 50 sccm, and N.sub.2 was simultaneously fed as an inert gas to provide dilution at a flow rate of 450 sccm to adjust the ClF.sub.3 concentration to 10 vol %. The wafer sample was processed for 30 sec. at 400° C. and a pressure of 100 Torr. As a result, all the Poly-Si film and SiO.sub.2 film were removed (etching rate of Poly-Si was 600 nm/min or higher, and the etching rate of SiO.sub.2 was 200 nm/min or higher), but the Si substrate was badly damaged, and the weight change rate was −1.69%.

Comparative Example 4

(17) A wafer sample similar to Example 1 was placed inside the processing vessel of the heatable vacuum device, and ClF.sub.3 was fed from the capturing vessel through the mass flow controller at a flow rate of 400 sccm, and N.sub.2 was simultaneously fed as an inert gas to provide dilution at a flow rate of 100 sccm to adjust the ClF.sub.3 concentration to 80 vol %. The wafer sample was processed for 30 sec. at 400° C. As a result, all the Poly-Si film and SiO.sub.2 film were removed (etching rate of Poly-Si was 600 nm/min or higher, and the etching rate of SiO.sub.2 was 200 nm/min or higher), but the Si substrate was badly damaged, and the weight change rate was −5.51%.

Comparative Example 5

(18) A Si wafer sample and processing device similar to Example 1 were used, and ClF was applied as the monofluorohalogen compound. ClF was fed from the capturing vessel through the mass flow controller at a flow rate of 100 sccm, and N.sub.2 was simultaneously fed as an inert gas to provide dilution at a flow rate of 400 sccm to adjust the ClF concentration to 20 vol %. The wafer sample was processed for 30 sec. by adjusting the device interior to a temperature of 300° C. and a pressure of 100 Torr. As a result, Poly-Si was etched at an etching rate 374 nm/min, and a Poly-Si film averaging 114 nm remained.

Example 5

(19) Used as test specimens were materials commonly applied to the interior of the processing vessel of the thermal CVD device: graphite (C), alumina (Al.sub.2O.sub.3), aluminum nitride (AlN). Their respective dimensions were 20×20×5 mm (3.6619 g), 20×20×2 mm (3.2529 g), and 20×20×2 mm (2.6453 g). Each test specimen was sealed in a reactor made of Ni, φ2B, and having 1 m of length, and ClF was applied as a monofluorohalogen compound to assess the weight change rate from an unprocessed state, and to perform a composition analysis by SEM-EDX. The test was performed by achieving a vacuum state inside the reactor in which the test specimen was sealed using a vacuum pump, and ClF was fed without being mixed with inert gas from the capturing vessel through the mass flow controller until a normal pressure (0.1 MPaG) was achieved, and to expose the test specimen at a condition of 600° C. for 24 hours. As a result, the following weight change rates of the test specimens were obtained: graphite (−0.40%), alumina (+0.03%), aluminum nitride (+0.05%).

Comparative Example 6

(20) An experimental operation similar to Example 5 was performed using ClF.sub.3 similar to Comparative Example 1. Test specimens of graphite, alumina, and aluminum nitride were used, the respective dimensions being 20×20×5 mm (3.6577 g), 20×20×2 mm (3.2476 g), and 20×20×2 mm (2.7163 g). The interior of the reactor that encapsulates the test specimen was made vacuum by a vacuum pump, and ClF.sub.3 was fed without being mixed with inert gas from the capturing vessel through the mass flow controller until a normal pressure (0.1 MPaG) was achieved, and the test specimen was exposed at a condition of 600° C. for 24 hours. As a result, the following weight change rates of the test specimens were obtained: graphite (−1.02%), alumina (+0.45%), aluminum nitride (+0.66%).

(21) Tables 1, 2 and 3 shown below show results of an analysis using SEM-EDX of the composition of an unprocessed sample, and samples processed in Example 5 and Comparative Example 6. When comparing the results of Example 5 and Comparative Example 6, Comparative Example 6 exhibits a weight change rate and fluorine atom content of the sample surface which are larger than those of Example 5. This result indicates that a use of a halogen fluoride compound represented by XF (wherein X is Cl, Br or I) keeps the damage of the material of the device interior small in the actual cleaning operation of the semiconductor device.

(22) TABLE-US-00001 TABLE 1 mass concentration [wt %] C O F blank 98.9 1.1 — Example 5 98.4 1.1 0.5 Comp. Example 6 97.6 1.0 1.4

(23) TABLE-US-00002 TABLE 2 mass concentration [wt %] Al O F blank 46.3 53.7 — Example 5 41.6 42.1 16.3 Comp. Example 6 33.2 25.0 41.8

(24) TABLE-US-00003 TABLE 3 mass concentration [wt %] Al N O F blank 32.2 54.7 13.1 — Example 5 40.7 45.3 0.7 13.3 Comp. Example 6 44.9 19.3 0.0 35.9