JPS6059739A - Dry cleaning method - Google Patents

Abstract

PURPOSE:To remove a film which contains silicon covered on the interior of a film forming device at a high etching speed by generating a plasma with mixture gas which contains carbon tetrafluoride and sulfur hexafluoride in the device. CONSTITUTION:A plasma is generated with mixture gas which contains carbon tetrafluoride, sulfur hexafluoride and oxygen in a film forming device, and the film which contains silicon covered on the interior of the device is removed by etching. For example, flow rate ratio of the mixture gas is, for example, set to CF4:SF6:O2=40:40:20, the pressure in a sputtering device is set to approx. 1torr., and high frequency power is applied between a substrate electrode 11 and a cleaning electrode 13 to generate the plasma.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) TECHNICAL FIELD OF THE INVENTION The invention relates to improvements in dry etching methods for film forming apparatus.

(b) Background of the technology - In the manufacturing process of semiconductor devices, for example, polycrystalline silicon (St), silicon dioxide (StOt), silicon nitride (St s N4'), or phosphosilicate glass (PSG) 7! In many cases, the entire thin film is formed. These thin films are produced using chemical vapor deposition method (hereinafter referred to as CVD).
However, sputtering methods are also used.As the scale of integration of semiconductor integrated circuit devices increases, it becomes increasingly necessary to improve the reliability of semiconductor integrated circuit devices. Improving thin film properties and reducing defects are becoming increasingly important in the formation process.

(C) Prior art and problems Thin film formation by the CVD method, sputtering method, etc. is performed in a sealed device as is well known, and the thin film forming material is applied not only to the target substrate but also to the electrodes supporting the substrate. The film adheres widely to various parts of the manufacturing equipment, such as the walls of the equipment 173. Films that adhere to various parts of the equipment become a source of contamination, such as when they peel off and fall, so they must be removed frequently. There must be.

It is troublesome to disassemble and clean such a device in order to remove the film deposited inside the device, and the device 1
A dry cleaning method is preferred in which dry etching is performed by forming plasma in the FF 3 that reaches the inner wall and the like.

FIG. 1 is a schematic diagram showing an example of dry cleaning using a plasma CVD apparatus. In the figure, 1 is a substrate electrode, 2
1' is the upper electrode, 3 is the cleaning electrode, 4 is the yambar wall, 5 is the gas pipe, and 6 is the exhaust pipe. 0 When forming a thin cap with a non-equipment, the substrate electrode 1 is usually grounded. This is done by applying high frequency power between the upper electrode 2 and turning the raw material gas into plasma. At this time, as mentioned above, the substrate electrode 1 (7I) is covered with a thin film type M and Q on the inner surface 1 of the chamber wall 4.

When this material to be subjected to M is the silicon-based material mentioned above,
In conventional dry cleaning, the etchant is carbon tetrafluoride (CF4):oxygen (0□) = ao
: A mixed gas of 6 degrees Celsius or a mixed gas of about sulfur hexafluoride (SR):e (02)-80:20 is used. That is, these etchant gases are added to gas d′f1
5 into the chamber wall 3. For example, o, a[
By applying madder frequency power of about W/i), plasma is formed and the film adhering to the -Cs forming circle is etched away. In this etching, the cleaning rL'tL 3 i4 has the effect of spreading the plasma widely within the apparatus and etching the inner wall of the chamber, etc.

However, when using the conventional etchant gas, there is a problem that the etching rate is low and the dry etching process takes a long time.

That is, for example, when the coating M film is 5i3N, in the above example of C1'', +02, the etching rate is about 1100 (n/m1n) for the electrode 4 and the chamber inner wall (σ), and In the case of S Fa "C kill, the separation rate is low and the plasma spread9 is less than that of CF4"02, so the electrode part has 600 Cnm/mi.
n], but the chamber inner wall Mli is 100
[: nm/m1n)].

As mentioned earlier, the need for dry cleaning of plasma CVD equipment, low pressure CVD equipment, sputtering equipment, etc. is increasing to ensure and improve the reliability of semiconductor devices. In response to the demand for a method that can be carried out effectively, it is the object of the present invention to provide a dry cleaning method that removes at a high etching rate a film containing silicone coated inside a film forming apparatus using a method such as sputtering. 6) Structure of the Invention The object of the invention is to generate a plasma in a film forming apparatus using a mixed gas of tetrafluoride fiber, sulfur hexafluoride, mature wood, and a completely depleted gas. 0 (f) Embodiments of the invention that can be achieved by a dry cleaning method that etches and removes the silicone film adhered to the inside. ) The BLhu forming apparatus is, for example, a plasma CVD apparatus as shown in FIG. 1, or a spackling apparatus as shown in FIG. Of course, it is necessary to have the means to do so.

In the sputtering apparatus shown in FIG. 2, 11 is a substrate electrode, 12 is a target, and 13 is a cleaning shielding plate, and the shielding plate 19 is placed in front of the substrate to protect the target rattle in addition to cleaning. uses a mixed gas of CF, SFa, and 02 as the etchant gas for cleaning,
The flow rate ratio of CF4 and SF is 20 to 60, respectively.
[Cleft] degree, CF' in 0-2 crotch with 02 being about 20%
When increasing the flow rate ratio of 4, the plasma spreads well and S
When increasing the flow rate ratio of Fa, there is a tendency for plasma to gather between the electrodes, and the optimal value of the flow rate ratio between CF4 and SFa depends on factors such as the arrangement of the TJL pole and the thickness distribution of the deposited film. Select. As already mentioned, O6 has an acoustic effect that prevents the formation of non-volatile polymers.
:SFa: 02”'40: 40: 20
For example, the pressure inside the device is set to 1 [torr] ip*t, and the substrate electrode 1 or 11 and the cleaning electric coffin 3 or 1 are connected to each other.
It is necessary to apply a convex frequency power of about 0.3 (W7crd E) to the 114'' of Example 2 to generate the entire plasma. Sometimes, even when there is a gap between the electrode part and the inside of the chamber, s 0
0 Cn m/min) The device can achieve a high etching speed close to the etching speed obtained only in the electrode section in the conventional example using SFe'02 mentioned above. 11. 02F, which can be produced on the entire internal surface, the mixed gas includes polycrystalline silicon (Sl), silicon dipropylene (Si02) in addition to silicon nitride (Sis).
, - silicon oxide (SIO) r silicon nitride (Si
Similar effects can be obtained with silicone cubital membranes such as xOyNz) and fItRyjsis, and the formation of the 50-occlusal film-forming pouch and the placement of the '1 penile membrane are also limited to the Kashukuzou as previously described The present invention can be applied to a device having the following structure.

(g) As described in detail, the present invention prevents the removal of a silicon-containing film deposited on the inside of a film-type growth often used in the manufacturing process of semiconductor devices, etc. , it is possible to improve the effectiveness of dry cleaning, and it is possible to achieve the effect of promoting improvements in semiconductor devices and other products.

[Brief explanation of the drawing]

Figure 1 and Figure 2 show an example of a film forming device to which the invention can be applied. Cleaning Cic poles, 4 and 14 are chamber walls, 5 and 1
5 is the gas field person d16 and 16 is ``futokiei'', 12 is kugeno), 17μ cathode, 18 is anode, 19 is the final root capsule.

Claims (1)

[Claims] A plasma is generated in a film forming device using a mixed gas containing carbon tetrafluoride, sulfur hexafluoride, and oxygen, and a film deposited inside the device and containing silicon is etched away. Dry cleaning method.