JPH02194527A - Removal of film - Google Patents

Abstract

PURPOSE:To uniformly and sufficiently removed a film formed on an object whose film is to be removed by using a small amount of an etching solution by a method wherein the etching solution which has been made mistlike fine particles is supplied to the inside of a chamber which has housed the object whose film is to be removed. CONSTITUTION:A bell jar 16 as an object whose film is to be removed is housed inside a chamber 15; after that, a solenoid valve 27 for etching-solution supply use and a solenoid value 29 for cleaning-gas supply use are set to an open state; an etching solution 24 inside a tank 25 is sucked up by a sucking force of a cleaning gas supplied to a two-fluid fine spray nozzle 18; the solution is transformed into mists simultaneously with an operation by which the gas flows out from the nozzle; mistlike fine particles (particle diameters of 1 to 300mum) are supplied to the inside of the chamber 15. After the particles have been supplied for a definite time, the valve 27, 29 are closed and are on standby for a required time. During this time on standby, the mistlike fine particles of the etching solution 24 uniformly adhere to the whole surface of the bell jar 16 as a thin-film shape; this film is chemically reacts with a film which has been formed on the bell jar 16. A gas generated by this chemical reaction overcomes a viscosity of the thin-film shape etching solution 24 and are discharged easily into the chamber 15.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applied to semiconductor wafers on which a film is formed, thermal diffusion furnaces for semiconductor device manufacturing, etc. in a wet process using mixed acids in the manufacturing process of semiconductor devices. The present invention relates to a coating removal method for removing coatings from coating-removed items such as furnace core tubes, jigs, pel jars, etc. used in

[Prior Art] Conventionally, as shown in FIG. 3, this type of film removal method includes, for example, a method in which a wafer 1 (Si, GaAs) is immersed in an etching solution 3 contained in a processing layer 2;
Alternatively, as shown in FIG. 4, there is a method in which, for example, a plurality of spray nozzles 5 are arranged inside and outside a Pel jar (made of quartz) 4 and the etching solution is sprayed onto the surface of the Pel jar 4.

[Problem to be solved by the invention] However, the former problem! In the M removal method, for example, when removing a coating formed on the wafer 1,
Gas 6 (
(see FIG. 1) adheres to the surface of the wafer 1 in the form of bubbles, making it impossible to remove the coating uniformly. For example, as shown in FIG. 5, a chamber 7 is provided above the processing layer 2,
The chamber 7 can be kept in a vacuum and degassed, or as shown in FIG. need to be removed.

For this reason, there are disadvantages in that the device becomes expensive and the number of failure factors increases. Furthermore, since the composition of the etching solution 3 changes over time due to chemical reactions, it is necessary to frequently exchange the solution. Therefore, a large amount of etching solution 3 is used, which has the drawback of increasing running costs. Furthermore, with the increasing integration of memory, cell capacitors have changed from the brainer type to the trench type, which utilizes the space in the thickness direction of the wafer 1. Cleaning the groove 9, which has a width of 1 μm and a depth of 4 μm, has become a very difficult problem.

In addition, heat diffusion furnaces for semiconductor device manufacturing, CVD (Che
Furnace core tubes (made of quartz, made of SiC), jigs and tools (made of quartz, made of SiC) used in micaf Vaper Deposition furnaces, epitaxial growth layer disc-shaped furnaces, etc.
Or, when removing a coating formed on Pelger (made of quartz), for example, since the furnace core tube 10 has a length of about 3 m, a large burial tank 11 is used as shown in FIG.
Not only that, but also a large amount of etching solution 3 is required. Therefore, the device becomes large and expensive.

On the other hand, in the latter film removal method, in order to uniformly remove the film, the support 12 (fourth
This method has the disadvantage that it requires a rotating mechanism (see figure) and a lifting mechanism (both not shown).

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a film removal method that can uniformly and sufficiently remove a film formed on a film-removed object using a small amount of etching solution.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention is a method of supplying an etching solution in the form of fine particles in the form of mist into a chamber containing a film to be removed.

[Function] In the above means, the n-shaped fine particles of the etching liquid uniformly adhere to the surface of the object from which the film has been removed in the form of a thin film, and the gas generated by the chemical reaction with the film forms a thin film of the etching liquid. It is easily released into the chamber due to its viscosity.

The size of the fine particles is preferably 1 to 300tim, and 1μ
If it is less than 300 μm, etching will take a long time.
If it exceeds this, it becomes difficult for the etching solution to adhere uniformly.

[Example] An example of the present invention will be described below with reference to FIGS. 1 and 2.

FIGS. 1 and 2 are a schematic configuration diagram and a partially sectional perspective view of a film removing apparatus used for carrying out the present invention.

In FIG. 1, reference numeral 15 denotes a chamber, in which a quartz Pelger 16 from which the film is removed is supported and accommodated by a support 17 whose contact area with the Pelger 16 is reduced. Further, in the chamber 15, a plurality of two-fluid fine injection n nozzles 18 are arranged above and below the Pelger 16, facing the same. These chambers 15, etc. have an intake register 19a on the front as shown in FIG.
It is provided in an acid-resistant casing 22, which has a front door 19 that can be raised and lowered, and an exhaust register 21 for forced ventilation connected to an exhaust duct 20 attached to the upper part of the rear surface.

In Fig. 2, reference numeral 23 denotes an inner door for preventing scattering of the etching solution, which can be opened and closed in two parts from the center of the front opening in the left and right directions, and opened to the left and right when the Pelger 16 is inserted and taken out, and is opened to the left and right during film removal. This prevents the highly acidic etching solution from scattering into the housing 22 (chamber) and causing corrosion, and prevents the solution from scattering to the outside and causing consumption.

As shown in FIG. 1, each of the two-fluid fine 9n nozzles 18 has a tank 25 containing an etching liquid 24, a clean gas supply source 26, a first conduit 28 with an etching liquid supply electromagnetic valve 27 interposed therebetween, and Solenoid valve 29 for clean gas supply
They are connected by a second conduit 30 interposed therebetween. A normal pressure gas supply source 31 for cleaning is connected to the first pipe line 28 via a branch pipe line 33 with a normal pressure gas supply electric valve 32 interposed therebetween, while the second pipe line 30 A pure water supply source 34 for cleaning is branched and connected through a branch pipe line 36 with a pure water supply electric valve 6i1 interposed therebetween. In the actual device, the tank 25 is provided at the lower right side inside the housing 22, as shown in FIG.

Further, as shown in FIG. 1, the lower part of the chamber 15 is connected by a discharge pipe 39 with a discharge port 37 and a common discharge electromagnetic valve 38 interposed therebetween.

The discharge pipe 39 is connected to the discharge common electromagnetic valve 3.
It is connected to the tank 25 by a branch discharge pipe 40 that branches downstream of the tank 8 .

As shown in FIG. 2, the electromagnetic valves are controlled in a predetermined order and at predetermined time intervals by an operation panel 41 attached to the front of the housing 22 and a sequence control device (not shown) that works in conjunction with the operation panel 41. It is opened and closed under the

In the film removal apparatus having the above structure, after the Pel jar 16 is housed in the chamber 15, the etching liquid in the tank 25 is removed by opening the etching liquid supply electromagnetic valve 27 and the clean gas supply electromagnetic valve 29. 24
is sucked up by the suction force of the clean gas (atomization air pressure 3.0 kg/cm2) supplied to the two-fluid through-spray nozzle 18, and at the same time as the gas exits from the nozzle, it is atomized into atomized fine particles (particle size 1 ~300μm) and chamber 1
Supplied within 5 days. After supplying the etching solution for a certain period of time, the electromagnetic valve 27 for supplying etching liquid and the electromagnetic valve 29 for supplying clean gas are closed, and the etching solution is waited for a required period of time.

During the waiting time, the fine particles of the etching liquid 24 uniformly adhere to the entire surface of the Pel Jar 16 in the form of a thin film, causing a chemical reaction with the coating formed on the Pel Jar 16. The gas generated by this chemical reaction overcomes the viscosity of the thin film of etching liquid 24 and easily fills the chamber 15.
released within.

After the required standby time has passed, the normal pressure gas supply solenoid valve 32,
Pure water supply solenoid valve 35 and discharge common solenoid valve 3
By opening 8, the two-fluid characteristic jet π nozzle 18
The atmospheric pressure gas and pure water are mixed by the suction force of the pure water (supply pressure 2.0 kg/cm2) supplied to the unit, and the pure water, which has an increased cleaning effect and is atomized, is delivered to each two-fluid continuous spray nozzle. The etching liquid 24 is supplied from 18 to the entire surface of the Pelger 16.
The liquid after the chemical reaction between the cleaning liquid and the coating is washed, and this cleaning liquid is discharged from the outlet 37 to the outside of the machine.

It is desirable to repeat the fine spraying of the etching liquid 24 several times in order to cope with changes over time due to chemical reactions between the etching liquid 24 and the film. It is refluxed to the tank 25 via the discharge pipe 40.

[Effects of the Invention] As described above, according to the present invention, the atomized fine particles of the etching solution uniformly adhere to the surface of the film-removed object in the form of a thin film, and the gas generated by the chemical reaction with the film is released. Since the viscosity of the thin film-like etching solution is overcome and it is easily released into the chamber, it is not necessary to consume a large amount of etching solution and pure water, which accompanies the complexity and size of conventional film removal equipment. The film can be removed uniformly and sufficiently using the etching solution, and since the amount of etching solution used is small, the amount of pure water used can be reduced compared to the conventional method.

[Brief explanation of the drawing]

￥S1 Figure and Figure 2 are a schematic configuration diagram and a partial cross-sectional perspective view of a film removal device used for carrying out the present invention, and Figures 3 and 4 are explanatory diagrams of conventional immersion type and spray type film removal methods. , Figures 5 and 6 are explanatory diagrams of gas removal means in the immersion type coating removal method, Figure 7 is a partially enlarged sectional view of a wafer, and Figure 8 is a diagram showing the coating on the furnace core tube by the immersion type coating removal method. It is an explanatory view of a removal means. 15...Chamber 16...Pelger 17.
... Support tool, 18 ... Two-fluid fine spray n nozzle, 24 ... Etching liquid, 25 ... Tank, 26 ...
・Clean gas supply source, 27...Etching? Solenoid valve 28 for nighttime candy...
- First pipe line, 29... Solenoid valve for clean gas supply 30... Second pipe line.

Claims (1)

[Claims] (1) A film removal method characterized by supplying an etching solution in the form of fine particles in the form of mist into a chamber containing a film to be removed.