JPH01102921A - Manufacture of film - Google Patents

Abstract

PURPOSE:To remove a film formed on a wall part and a powder applied to the wall part inside a reaction chamber and a resonance space by a method wherein the inner wall of a film formation apparatus by means of electron cyclotron resonance is etched by using the electron cyclotron resonance before and after formation of the film. CONSTITUTION:A film is formed by using an electron cyclotron resonance type plasma CVD apparatus while a pressure inside a reaction chamber 1 and a resonance space is set at 1X10<-3>-1X10<-4>Torr; after that, nitrogen fluoride (NF3 as a representative) is supplied through a line 18; an etching operation is executed at a pressure of 1X10<-2>-1Torr which is more than the pressure during formation of the film. Microwaves from an oscillator 3 are supplied to the resonance space 2 through a quartz window 29; a magnetic field is impressed by air-core coils 5, 5'. The etching operation is to be concentrated on the film applied inside the resonance space and inside the reaction chamber in accordance with a kind and an applied degree of the film.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a film using electron cyclotron resonance.

[Conventional technology and its problems]

Conventionally, when forming a film using electron cyclotron resonance, the film was formed on the walls constituting the resonance space and the inner wall of the reaction chamber, or the powder adhered thereto. However, the coating or powder formed on this inner wall easily separates, so the detached coating or powder flies off and adheres to the substrate, creating snowflakes, etc., and as a result, pinholes are formed in the formed coating. There were other drawbacks.

Therefore, when a semiconductor device is manufactured using the above film, the resultant semiconductor device has extremely poor characteristics.

The present invention has been made for the purpose of removing coatings formed on the inner walls of the reaction chamber and the resonance space and powder adhered thereto.

[Means to solve the problem]

The present invention provides a film forming apparatus using electron cyclotron resonance, which has a reaction chamber provided with a substrate on which a film is to be formed and a resonance space in which a gas to be activated is activated into a plasma state. The inside of the reaction chamber and the resonance space is etched by a semiconductor device manufacturing method characterized by etching the film or powder attached to the inner walls of the reaction chamber and the resonance space using electron cyclotron resonance at a pressure higher than the pressure. It is possible to remove the coating formed on the wall of the wall and the powder adhering to it.

The present invention will be explained in detail below with reference to Examples.

〔Example〕

FIG. 1 shows an outline of a cyclotron resonance type plasma CVD apparatus used in the present invention.

In the drawing, a stainless steel reaction vessel (1") has a loading chamber and an unloading chamber installed at the front or rear through a gate valve (not shown). From this loading chamber, a cylinder is inserted into the reaction vessel shown in Figure 1. A frame structure that constitutes a shaped space (a structure that is surrounded on all sides by stainless steel metal or insulating plates to prevent reactive gas in an active state from spreading to the inner wall of the outer container and causing flakes) (31), (
31'). Furthermore, a substrate holder (10') is disposed within this frame structure, and a substrate (10) is provided in pairs so that a coating is formed on the main surface of both sides of the substrate holder (10'). In the drawing, ten substrates are arranged in five holders (10').

The cylindrical space of the container (1') is provided as a reaction space (1). A heating chamber (7°) having a halogen lamp heater (7) is provided on the side of this container (1°). Infrared rays are transmitted through the quartz window (19) to the frame structure and the substrate (l
O) is irradiated and heated. Furthermore, in order to provide a glow discharge if necessary, a pair of mesh electrodes (20) and (20') are provided at the upper and lower parts of the inside of this container (1"), and a high frequency or DC power supply (6) is provided here. More than 13.56M+
12 or apply a direct current electric field.

In addition, a non-product gas such as argon (a gas that itself produces only a gas even if decomposed or reacted) is supplied to the resonance space (2) from (18). Outside this resonance space (2), air-core coils (here used as Helmholtz coils) (5) and (5') are arranged to apply a magnetic field. A cooling pipe (12) is arranged inside this.

At the same time, the analyzer (4) is activated by the microwave oscillator (3).
), for example, a 2.45 GHz microwave is transmitted through a quartz window (
29) to the resonance space (2). In this space, argon (18
). Then, a magnetic field determined by its mass and frequency (e.g. 875 Gauss) is applied to the air-core coil (5),
(5') is added.

For this reason, the argon gas is excited and resonates at the same time as it is pinched by the magnetic field, and after being sufficiently excited, the reaction space (1
) is released as electrons and excited argon gas (21
) to be done. At the outlet of this resonance space (2), product gas is discharged (22) from the doping system (13) through (16) into the reaction space from a plurality of nozzles (17). As a result, the product gas (a gas that decomposes or reacts to produce a solid) (22) is excited and activated by the electrons and the excited gas (21). An insulating homogenizer (20) was provided to prevent this activated gas from flowing back into the resonance space (2). In addition, a pair of electrodes (23
), (23'') are simultaneously applied to these reactive gases.

As a result, there is substantially a buffer space (30) between the resonance space (2) and the reaction space, and electrons and excited gas (21) are emitted so as to fall over the entire reaction space.

That is, efforts were made to maintain the excited state of the reactive gas even if the resonance space and the formation surface are sufficiently far apart (generally 20 to 80 cm). (When using only cyclotron resonance, the distance between the substrate and the edge of the resonance space is 5 to 1
It is as short as 5 cm, causing non-uniformity in the thickness of the coating. ) Also, in order to sufficiently spread the reactive gas in the reaction space (1) and to generate a cyclotron, there is a reaction space (1).

The pressure in the resonance space (2) is 1 xto-"~IXl0-
'torr, for example, 3 x 10-' torr. This pressure was achieved by adjusting the displacement of the vacuum pump (9) using the control pulp (15) of the exhaust system (11) in conjunction with the turbo molecular pump (14).

After film formation is performed using an electron cyclotron resonance type plasma CVD apparatus having the above-described configuration, etching is performed under the pressure conditions of the present invention. The gas used for etching is nitrogen fluoride (etching gas such as NF, NF2, NF3, etc., typically NF3). First, the pressure in the reaction space is set to a pressure higher than the pressure during film formation, lXl0-”~l torr.
, in this example, was set to O and 1 torr. And Figure 1 0
8) NF, from 100 to 400 cc/min, e.g. 20
The microwave was supplied at a rate of 0 cc/min, and a frequency of 2.45 GH2 was supplied with an output of 200 to 800 W, for example, 400 W. The resonance intensity of magnetic field (5), (5°) is 875±1
It was adjusted to resonate in the range of 0.00 Gauss. The thickness and extent of the coating deposited or formed on the inner walls of the reaction chamber and resonance space vary depending on the type of coating, coating speed, coating temperature, etc., and there are also differences between the reaction chamber and the resonance space. Therefore, depending on the type of film and the degree of adhesion, the etching of the present invention may be performed with emphasis on the film deposited within the resonance space, or with emphasis on the film deposited within the reaction chamber. It is better to do this as appropriate. It is also possible to etch only the inside of the resonance space.

Etching as described above may be performed before and after film formation.

[Embodiment 2] In this embodiment, a plurality of electron cyclotron resonance type plasma CvD apparatuses shown in FIG. 1 are connected and integrated to form a multi-chamber system.

Regarding this multi-chamber system, a patent filed by the present inventor (II5P 4.505.950 (198
5, 3, 19).

USP 4,492.716 (19B5.1.8)
') is already obvious. However, this embodiment specifically integrates this multi-chamber method and the ECR method,
We were able to obtain a multi-chamber system that is superior to conventional methods.

The present invention will be described according to FIG.

Figure 2 shows systems I, ■, ■, ■, ■. Here, a load chamber (systems ① and Ⅲ), a first coating, for example, a reaction system for forming a P-type semiconductor (system ①), a second coating, for example, a reaction chamber for forming an I-type semiconductor (system III), a third coating, for example, It has a reaction system for forming an N-type semiconductor (system ■), an unloading system (system v, v'>,
This is an example of producing a film to have a laminated structure of a plurality of films. For example, a PIN junction can be obtained as a laminate.

The rooms of each prefecture are (1'-1'), (1"-1), (1"-2
), ... (lo-5), (1'-5"), and especially (1-2), (1-3), (1-4)
constitutes the reaction space. It also has (1-1'L (1-1)) as a space on the loading side, and (1-5) and (1-5''') as spaces on the unloading side.Doping system (13-2 ), (13-3),
(13-4) exists. Furthermore, turbo molecular pumps (14-1), (14-2), ・
...(14-5), vacuum pump (9-1), (9-
2) , ... (9-5). System (B), (V'
) are loading and unloading chambers, which are omitted from illustration.

Microwaves for ECR include at least one of the systems ■, ■, and ■.8-2), (8-3),
(8-4) and Helmboltz coil (5
-2), (5'-2).

... has been added as a closure. And resonance space (2-2)
.

(2-3), (2-4), argon gas or a mixed gas of this and a non-product gas (18-2),
(18-3) and (1B-4) are added.

A buffer space (25-2) is provided between each chamber (1-1) and (1-2), and a buffer space (25-2) is provided between each chamber (1-2) and (1-3). -3), and between (1-3) and <1-4) there is a buffer space (2
5-4), and further has a buffer space (25-5) between (1-4) and (1-5). In these buffer spaces, the substrate (10) and the substrate holder (frame structure constituting the cylindrical space) (31) can be transferred to the next chamber after forming a film in a predetermined chamber (reaction container). Also, in order to prevent impurities and reaction products in one space from mixing into the adjacent reaction space during film formation, the width is made wider than the mean free path of the gas, so that each reaction space (1-1),...
- (1-5) are spaced apart from each other. Furthermore, a gate valve (25-1) between the load chamber (1-1") and the load buffer chamber <1-1), a gate between the unload buffer chamber (1-5) and the unload chamber (1-5') The valve (25-6) prevented atmospheric air from entering the reaction spaces (1-2)...(1-4) during loading and unloading of substrates and substrate holders.

After etching each chamber of the above device in the same manner as in Example 1, a PIN type photoelectric conversion device was fabricated.

In system (2), a P-type Si, CI-X (0<X<1) non-single crystal semiconductor was formed. i.e. reaction space, height 30c
m, width and depth each 35 cm, and the inner dimensions of the reaction vessel are height 40 cm, width and depth each 50 cm, and a substrate (20 cm).
x30cm, 10 sheets) is considered as one batch. Further, the pressure in this reaction space was set to 3 x 10-'torr, and argon was supplied at 200 cc/min as a non-living gas at 0ω. In addition Hisi (CH3)z /S i Ha
= 1/7, B,)1. /SiH,=5/100
0 and was supplied from (13-2) at 80 cc/min.

The initial high frequency energy was supplied using a power of 40W. Microwaves have a frequency of 2.45 GHz and 200
A power of ~800W was supplied, e.g. 300W.

The resonance intensity of the magnetic field (5-2) and (5'-2) is 875±
It was adjusted to resonate in the range of 100 Gauss.

As the substrate 0ω, a glass substrate or one on which a transparent conductive film was formed was used.

The substrate temperature was set to 180° C., and an optical conductivity of 3×10−” (S cm−′) was obtained with an optical Eg of 2.4 eV.

In system (1), a (2) type non-single crystal semiconductor was formed. That is, argon was excited into the resonance space, and monosilane was supplied from 13-3 at a rate of 80 cc/min. Microwave output is 400
The test was carried out under the following conditions: W, pressure 3XIO-'torr.

In system (2), an N-type microcrystalline non-single crystal semiconductor was formed. That is, SiH4/Hz = 115 to 1/40, for example 1/30, and P11+/5i114 = 1/100.

ECR output 400W, pressure 3 x 10-' tor
r, the substrate temperature was 250°C. Then optical Eg=
An electrical conductivity of 1.65 eV and an electrical conductivity of 50 (Scm-') were obtained. In particular, in the ECR method, even if the microwave output is increased, there is no sputtering effect on the substrate, so the average grain size is large and it is easier to polycrystallize than the 100 to 300 particles, and as a result, the crystallinity is also lower than the glow discharge plasma CVD method. It has become possible to increase this from about 50% to 70%. Furthermore, when comparing the amount of hydrogen to be diluted, in the glow discharge method and the plasma CvD method, dilution with hydrogen was large at 5il14/H2 = 1 no 80 to 1/300, but in the ECR method, Sign/Hz
= 115 to 1/40, it was possible to produce a semiconductor having a sufficient microcrystalline structure.

The photoelectric conversion device obtained as described above has a uniform coating without pinholes or the like.

Therefore, the conversion efficiency was 12.9% (1.05 cJ) (open circuit voltage 0.92V short circuit current density 18.4 mA/cd fill factor 0.76).

In this example, etching was performed before manufacturing the photoelectric conversion device, but it may be performed after manufacturing. Further, it may be carried out each time the coating is formed, or it may be carried out after the coating has been formed in the reaction chamber and the resonance space to some extent.

[Effects of the present invention]

As described above, according to the coating production method of the present invention, the deposits deposited on the inner walls of the reaction chamber and the resonance space in an electron cyclotron resonance plasma CVD apparatus can be removed before coating production, so that the deposits can be reduced to powder. It prevents the film from being mixed in the film as a lump with a large surface area and many interfacial units at its grain boundaries. This was effective in creating a film with

Furthermore, the nitrogen fluoride used in the present invention remains a chemically stable gas even after etching, and therefore has the advantage that it is substantially non-polluting even when released to the outside.

[Brief explanation of the drawing]

1 and 2 show a cyclotron resonance type plasma CVD apparatus used in the present invention.

Claims (1)

[Claims] 1. In a film forming apparatus using electron cyclotron resonance, which has a reaction chamber equipped with a substrate on which a film is to be formed and a resonance space in which the gas to be activated is activated into a plasma state, the film forming pressure is adjusted before and after film formation. A method for producing a film, which comprises etching a film or powder attached to the inner walls of a reaction chamber and a resonance space using electron cyclotron resonance under the above pressure conditions.