JPH02197576A - Thin film building-up device - Google Patents

Abstract

PURPOSE:To stably form a good-quality built-up film at the quick building-up velocity by providing a magnetic field generator to the outer periphery of a thin film building-up chamber and also scanning the magnetic field of the thin film building-up chamber parallel to the surface of a base plate in the case of forming the various thin films on the surface of the base plate by a plasma CVD method. CONSTITUTION:A base plate 109 such as an Si single crystal wafer is placed on a sample base 108 and introduced into a building-up chamber 107 being in a vacuum state. Inert gas such as He, Ne and Ar or inert gas contg. the elements constituting the main component of a built-up film is introduced through a gas introducing port 110. Microwave 102 is introduced into a plasma generating chamber 101 through an introducing window 104 from a waveguide 103 and plasma is generated and plasma flow 106 is supplied into the building-up chamber 107. Simultaneously the gaseous raw material of the built-up film is supplied into the building-up chamber 107 through a gas introducing port 111 and also DC current modulated by low frequency is allowed to flow to a solenoid coil 105 provided to the outer periphery of the building-up chamber 107. The magnetic field of the building-up chamber 107 is scanned parallel to the surface of the base plate 109 and the build-up film which has uniform thickness and excellent quality is formed on the base plate 109 at the quick building-up velocity.

Description

[Detailed Description of the Invention] [Technical field to which the invention pertains] The present invention relates to an apparatus for manufacturing thin films constituting electronic devices, etc., and in particular to an apparatus for depositing thin films of various materials on a sample substrate using plasma. Plasma CVD (C
(chemical vapor deposition)
The present invention relates to a thin film deposition apparatus using the method.

[Description of prior art]

The plasma CVD method has the advantages of (i) being able to form a deposited film at a low temperature of 200 to 400°C, and (it) not requiring heat resistance of the substrate; It is applied to the formation of amorphous silicon (A-SI) films and diamond thin films for solar cells, contact image sensors, and photosensitive drums.

The conventional apparatus for carrying out the plasma CVD method uses radio waves (RF) between two parallel plate-type electrodes that face each other.
The mainstream is one that generates plasma by injecting R
Since the F plasma CVD apparatus has a simple structure, it has the advantage of being easily upsized.

However, such conventional plasma CVD methods have
In any case, there are problems that require further resolution.

That is, problem (1): An ion sheath is formed on the substrate side, a negative self-bias appears, and the ion species in the plasma are attracted to the cathode side, causing an impact of the ion species on the anode where the substrate is placed. is relieved. However, ion species still remain incident on the substrate surface and are incorporated into the deposited film, causing an increase in internal stress and defect density, making it impossible to obtain a deposited film of good quality. Problem (2): Since the electron density is low at 10' to 1010, the decomposition efficiency of the source gas is not so high and the deposition rate is low. problem(
3): Because the electron temperature is as low as ~4 eV, raw material gases with high binding energy such as silicon halide compounds are difficult to decompose.

By the way, several proposals have been made to solve these problems. That is, in order to improve the above problem (11), a deposition method in which the radical generation region is separated using a plasma CVD apparatus in which a third electrode is added to the parallel plate plasma CVD apparatus as shown in FIG. has been proposed [A, Matsuda; J, Non-(:
ryst, 5olids, 59/60,687 (1
9831].

FIG. 2 is a schematic cross-sectional view showing an example of a typical apparatus for implementing the deposition method.

In FIG. 2, 201 is a cathode electrode, 202 is an anode electrode, 203 is a third electrode for radical separation, 204 is a high frequency RF power source, 205 is a reaction chamber, 206 is a gas inlet, 207 is a sample substrate, and 208 is a sample substrate. A heating heater 209 is an exhaust system.

When a-Si is deposited by the above deposition method, a high-quality a-3i film with a small unpaired electron density of IQIS~10"am-" can be obtained. However, it has the disadvantage that the deposition rate is very low, less than 1 person/sec.

In addition, in order to solve problems (1), (2), and (3) of the conventional RF plasma CVD method described above,
JP-A-56-155535, JP-A-59-301
A microwave discharge type plasma CVD apparatus using electron cyclotron resonance (ECR) as disclosed in Publication No. 8 has been developed. FIG. 3 is a schematic diagram showing a typical example of the ECR plasma CVD apparatus.

In FIG. 3, 301 is a plasma generation chamber having a cavity resonator structure, 302 is a microwave, 303 is a microwave waveguide, 304 is a microwave introduction window, 305 is a magnetic field generator, 306 is a plasma flow and a diverging magnetic field, 307 is a deposition chamber, 308 is a sample stage with a built-in heating heater, 309 is a sample substrate, 310 is a first gas inlet, 311 is a second gas inlet, and 312 is an exhaust system. In the ECR plasma CVD method using this device, since electrons resonate and absorb the energy of electromagnetic waves under ECR conditions (a magnetic flux density of 875 Gauss is required for microwaves of 2.45 GHz), the electron temperature is ~7 eV.
It has a high electron density of 1011. Therefore, 100
Deposition rates of ~1000 persons/min have been obtained. Further, the incident ion energy is ~20 eV, which is smaller than that of the parallel plate type plasma CVD method. Figure 4 shows the third
This figure shows the in-plane magnetic flux density distribution on the substrate surface 290 mm away from the magnetic flux density point under the ECR condition of 875 Gauss when the diameter of the plasma chamber 201 of the ECR plasma CVD apparatus shown in the figure is 170 mm. From the figure, it can be seen that the magnetic flux density is uniform in a small area of about 80 mm.

In this way, in the ECR plasma CVD method, the distribution of magnetic flux density on the sample substrate is reflected in the thickness distribution of the deposited film, so in order to obtain a deposited film over a large area, it is necessary to make the magnetic flux density uniform over a wide range. In other words, a large diameter solenoid coil is required. Therefore, a large-area thin film deposition apparatus using the ECR plasma CVD method requires a large-diameter solenoid coil, which has the disadvantage of being heavy, increasing the size of the apparatus, and increasing the manufacturing cost of the apparatus.

[Objective of the Invention J The object of the present invention is to eliminate the problems of the conventional plasma CVD method and apparatus described above, and to deposit a high-quality thin film over a large area and with a uniform thickness distribution at a high deposition rate. It is an object of the present invention to provide a thin film deposition method and apparatus that enable this.

[Structure and effects of the invention]

, the apparatus provided by the present invention comprises a plasma generation chamber having a means for introducing a gas to be activated and a means for introducing microwaves, and a deposition chamber having a means for introducing a gas containing a main component element of a deposited film. This thin film deposition apparatus is characterized in that a magnetic field generator composed of a solenoid coil is disposed around the outer periphery of the deposition chamber, and the magnetic field of the deposition chamber is scanned in a direction parallel to the surface of the sample substrate.

The main feature of the present invention is to make the distribution of magnetic field density on the sample substrate more uniform by scanning the magnetic field in the deposition chamber in a direction parallel to the sample substrate surface. by this,
It becomes possible to form a thin film over a large area with good thickness distribution.

The maximum value of the magnetic flux density generated by the solenoid coil used in the present invention is preferably 50 to 200 Gauss, and as the magnetic flux density increases, the solenoid coil becomes larger and weighs more, making it more expensive. Considering economic efficiency and operability, 5
More preferably 0 to 500 Gauss.

As the raw material gas used in the present invention, the following ones are used depending on the type of deposited film.

When depositing an amorphous silicon or crystalline silicon thin film, the source gas may be, for example, 5IH4 or Sit Ha containing silicon atoms.

S i F4. S i HFs, S t Hz Fa,
S i Hs F.

Sit Fs, 5iCI24, 5iHz Cβ,.

Examples include 5iHsC42. Note that S i C12
Liquid materials such as No. 4 are used after being vaporized by bubbling an inert gas. In addition to the above-mentioned raw material gases, gases used to generate plasma include H, F, and F.

Examples include C2* + He, Ne, Ar + Kr, and Xe.

The source gas for depositing an amorphous silicon germanium thin film is G e Ha or G e F containing germanium atoms in addition to the silicon atom containing source gas used for the above-mentioned amorphous silicon deposition.
4 etc. is used. Gases used to generate plasma include a mixed gas of a gas containing silicon atoms and a gas containing germanium atoms, as well as H, F, and
Cl2m.

Examples include He, Ne, Ar, Kr, and Xe.

The raw material gas for depositing a silicon nitride thin film is:
A gas containing silicon atoms used for depositing the amorphous silicon mentioned above, or Nl, N containing nitrogen atoms
A mixed gas of one or more gases selected from HI and NFs and a gas containing silicon atoms is used.

In addition to the above-mentioned source gases, raw material gases used for plasma generation include Nl, NHs, NFI, and H.

Examples include Fz, CJL, He, Ne, Ar, Kr, and Xs. In the case of forming silicon nitride, the raw material gas or the gas for generating plasma must contain at least a gas containing nitrogen atoms and a gas containing silicon.

The raw material gas for depositing a silicon oxide thin film is:
A gas containing silicon atoms used in the above-described deposition of amorphous silicon or a gas containing oxygen 02 and silicon atoms is used. In addition to the above gases, raw material gases used to generate plasma include Ox, Hz
, Fa, Cna.

Examples include He, Ne, Ar, Kr, and Xe. In the case of forming silicon oxide, the raw material gas or the raw material gas for plasma generation needs to be a gas containing at least Ol and silicon atoms.

As a raw material gas for depositing an amorphous silicon carbide thin film, the gas si (CHs
)4 containing silicon atoms and carbon atoms, or CH4, Cm Ha , Cs containing carbon atoms
A mixed gas of at least one kind of gas selected from H4, CmHa, etc. and the above silicon atom-containing gas is used. In addition to the above-mentioned raw material gases, the raw material gases used to generate plasma include carbon-containing gas, Ha
.

F s + CI21, He + N e + A
There are r + K r + X e, etc. In the case of forming amorphous silicon carbide, the raw material gas or the raw material gas for plasma generation needs to contain at least a gas containing carbon atoms and a gas containing silicon atoms.

The raw material gas for depositing a diamond thin film is:
CHa, Cs Hz containing carbon atoms.

CI H4, CI Ha, CHs C0CHs, CHI
Examples include OH. CHs C0CHs and CH,
OH is vaporized by bubbling of an inert gas and used. In addition to the above-mentioned carbon-containing gases, gases for generating plasma include H, F*, and C(lx).

Examples include He, Ne, Ar, Kr, and Xe.

As described above, the source gas may also be used as a plasma generation gas.

Furthermore, the raw material gas may be diluted with an inert gas such as He or Ar. When adding impurities to the deposited film, P Hs,
P F s, P F s, P Cβ,, PO2,.

B* Ha, BFs, BCJ2s, BBrs, A
sF5゜AsCl25, AsHs, Is, 5bH
s, 5bFs.

Mixing gases such as The reaction pressure for forming thin films of amorphous silicon, crystalline silicon, amorphous silicon germanium, silicon nitride, silicon oxide, and amorphous silicon carbide is 10-' to 10-' Tor.
Preferably it is r.

The reaction pressure to form a diamond thin film is 101~10"
Torr is preferred.

In the present invention, microwave discharge is used as a method for generating plasma, but in order to promote the reaction in the thin film deposition reaction, it is also possible to further apply optical energy such as ultraviolet light or laser light or thermal energy. be.

The specific content of the apparatus of the present invention is configured as shown in FIG. 1, for example. However, the present invention is not limited to this example device.

That is, in FIG. 1, 101 is a plasma generation chamber;
2 is a microwave, 103 is a microwave waveguide, 104 is a microwave introduction window, 105 is a solenoid coil, 106
107 is a plasma flow, 107 is a deposition chamber, 108 is a sample stage with a built-in heating heater, 109 is a sample substrate, 110 is a first gas inlet, 111 is a second gas inlet, 112 is an exhaust system, 11
3 is a magnetic field generator. Note that the microwave source, power supply connected to the solenoid coil, and exhaust pump are omitted.

The main feature of this ventral device is the solenoid coil 105.
The purpose is to make the thickness distribution of the deposited film formed on the surface of the sample substrate uniform by applying a DC power modulated at a low frequency and scanning a magnetic field parallel to the sample substrate in the deposition chamber.

The plasma generation chamber 101 has a cavity resonator structure.

When adding the magnetic field generating device 113 to the thin film deposition device,
Reflection of microwaves is reduced, making it possible to maintain stable discharge.

The method of operating the thin film deposition apparatus of the present invention is carried out as follows. Gas to be activated (for example, He, Neo Ar, Kr, etc.) from the gas inlet 110.

Introducing an inert gas such as is removed and introduced into the plasma generation chamber 101 through the microwave introduction window 104 to generate plasma.The generated plasma is transported to the deposition chamber and generated by a solenoid coil 105 arranged around the outer periphery of the deposition chamber. A source gas is introduced from the zero-order gas inlet 111 that scans the magnetic field, is decomposed, and a thin film is deposited on the sample substrate 109 .

[Film Formation Example IJ First, an example in which a silicon nitride film was formed using the thin film deposition apparatus shown in FIG. 1 of the present invention will be described. Note that the diameter of the plasma generation chamber was 170 mm.

The cleaned Corning #7059 glass substrate and silicon single crystal wafer substrate were mounted on the sample stage 108, and
Evacuate to a high vacuum region of 0-'Torr. N gas of 'losccm is introduced into the plasma generation chamber 101 from the gas inlet 110, and the pressure in the deposition chamber 107 is kept constant at 2X10.
-" Torr, and a permanent magnet with a center magnetic flux density of 200 Gauss is installed outside the plasma generation chamber, and 300 W of microwave power with a frequency of 2.45 GHz is applied. The zero order solenoid coil 105 generates 100 Gauss The magnetic field in the deposition chamber is scanned with a direct current of IKHz.Next, 20 sccm of S i H4 is introduced into the deposition chamber 107 from the gas inlet 111 and reacted for 10 minutes to deposit silicon nitride on the sample substrate. A film was formed. The thickness of the obtained silicon nitride film was 3700 on average, and the deposition rate was 6.2 people/sec. 30 cm x 30
The film thickness distribution in an area of cm was ±9%. A buffered hydrofluoric acid solution (
The etching rate with 50% HF:40% NH4F=15:85) was 73 people/min.

[Comparative Example 11] An example in which a silicon nitride film was formed using the conventional ECR plasma CVD apparatus shown in FIG. 3 will be described. Note that the diameter of the plasma generation chamber was 170 mm.

First, a cleaned Corning #7059 glass substrate and a silicon single crystal wafer substrate were mounted on the sample stage 308.
It was evacuated to a high vacuum region of 1X10-'' Torr. 40sccm of N2 gas was introduced into the plasma generation chamber 301 from the gas inlet 310, and the pressure in the deposition chamber 307 was kept constant at 2X.
10-” Torr, and the magnetic field generator 3
05, a magnetic field of 875 Gauss was applied in the plasma generation chamber, and a microwave of 2.45 GHz was applied at a power of 30
At 0 W, the microwave was introduced through the microwave introduction window 304 using the microwave waveguide 303 .

Then, from the gas inlet 311, 20 sccm of SiH,
was introduced into the deposition chamber 307 and reacted for 10 minutes to form a silicon nitride film on the sample substrate. The thickness of the obtained silicon nitride film was 400 mm at the part near the central axis of the plasma generation chamber.
0 people% 2100 at the edge of an area of 30cm x 3ocm
A, film thickness distribution in an area of 30cm x 30cm is ±19%
Met.

[Film formation example 2] An example of forming an amorphous silicon film will be described.

Using the same thin film deposition apparatus as in Film Formation Example 1, 100% SiH4, 200 sccm, was introduced from the gas inlet 110 as the reaction gas, and the pressure in the deposition chamber 107 was 6X10-
Torr and the substrate temperature were controlled at 200° C., and in the same manner as in Film Formation Example 1, a microwave power of 400 W was applied and the reaction was carried out for 20 minutes to form an amorphous silicon film on the sample substrate. The film thickness distribution of the obtained amorphous silicon in an area of 30 cm x 30 cm was ±7%, and the average film thickness was 11,900. The deposition rate is 9.9 people/sec
Met. As for the photoelectric properties of the obtained amorphous silicon film, the ratio σp/ad of the photoconductivity σp and the dark conductivity Od when irradiated with AM 1 (100 mw/crn') is 3X10'
Met.

[Comparative Example 2] An example of forming an amorphous silicon film using the ECR plasma CVD apparatus used in Comparative Example 1 will be described.

As the reaction gas, 100% SIH, 200 sccm was introduced from the gas inlet 210, and the pressure in the deposition chamber 207 was as follows.
Amorphous silicon film was formed on the sample substrate by applying microwave power of 400 W and reacting for 20 minutes using the same method as in Comparative Example 1, controlling the substrate temperature to 6×10-' Torr and 200''C. The thickness distribution of the amorphous silicon film is ±1 within an area of 30cm x 30cm.
It was 6%. The thickness of the amorphous silicon film is 14,500 people, 30 cm near the central axis of the plasma generation chamber.
At the edge of x30cm, there were 8,100 people. A.M.I.
(100mw/crn') As a photoelectric property during irradiation, the ratio op/ad of photoconductivity and dark conductivity is 1xlO' to 7x
It was lO'.

[Film Formation Example 31 An example of forming polycrystalline silicon using the thin film deposition apparatus used in Film Formation Example 1 will be described.

Hz 40sccm and ArAr using the same method as in film formation example 1
30sc was introduced through the gas inlet 110, and Sf*Fa
5sccm is introduced from the gas inlet 111, the pressure in the deposition chamber is set to l x 10 Torr, and the substrate temperature is set to 400°C.
The temperature was controlled at 0.degree. C., microwave power of 300 W was applied, and the reaction was allowed to proceed for 60 minutes to obtain silicon thin films on quartz glass and (110) single crystal silicon substrates. R of the obtained silicon thin film
The measurement results of HEED (high-speed reflection electron diffraction) revealed that it was crystallized. <11 on a quartz glass substrate
It was confirmed that the polycrystal has a 0> orientation, and that on a (110) single-crystal silicon substrate, it is an epiaxial growth with a (110) orientation. The film thickness distribution within the area of 30 cm x 30 cm was ±11%, the average film thickness was 7500 people, and the deposition rate was 2.1 people/Sec.

[Film Formation Example 41 An example of diamond formation using the thin film deposition apparatus used in Film Formation Example 1 will be described.

H2 dilution 50% CH410 was applied using the same method as in film formation example 1 with the magnet installed outside the plasma generation chamber removed.
1005c was introduced from the gas inlet 110, the pressure in the deposition chamber was controlled to 10 Torr, the substrate temperature was controlled to 800° C., microwave power of 250 W was applied, and the reaction was carried out for 60 minutes to form a thin film on a single crystal silicon wafer. The obtained thin film was confirmed to be diamond by Raman spectrum measurement. The SEM image of the diamond thin film shows that the grain size is 1.5 cm in the area of 30 cm x 30 cm in the deposition chamber.
It was found that a uniform diamond thin film of 5 to 2.0 μm could be obtained.

Film Forming Example 1 and Comparative Example 1, Film Forming Example 2 and Comparative Example 2, Film Forming Example 3,
From Film Formation Example 4, using the thin film deposition apparatus of the present invention, a dense silicon nitride film, an amorphous silicon film with good photoelectric properties, a polycrystalline silicon film with good orientation, and a diamond thin film were each formed over a large area with good uniformity. It is clear that

In addition, in film formation example 1.2.3.4, examples of forming silicon nitride, amorphous silicon, polycrystalline silicon, and diamond are shown, but the formation is not limited to this, and silicon oxide, amorphous silicon germanium, amorphous silicon carbide, etc. It is also effective as a manufacturing device.

[Summary of effects of the invention] As explained above, according to the present invention, the conventional plasma C
Compared to a VD device, the deposition rate is faster and a deposited film of good quality can be obtained. Furthermore, compared to the conventional ECR plasma CVD apparatus, it is easy to increase the area of the deposited film, and the productivity is excellent.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a thin film deposition apparatus according to the present invention. Figure 2 is a schematic diagram of a conventional radical separation type plasma CVD apparatus, and Figure 3 is a diagram of a conventional ECR plasma CVD apparatus.
4 is a schematic configuration diagram of the apparatus, and FIG. 4 is a diagram showing the distribution of magnetic flux density on the sample substrate surface of the ECR plasma CVD apparatus of FIG. 3. In the figure, 101.301...Plasma generation chamber, 102°302
...Microwave, 103,303...Microwave introduction tube, 104,304...Microwave introduction window, 105
...Solenoid coil, 106,306...Plasma flow, 107,205.307...Deposition chamber, 108.
308...Sample stage, 109.207,309...Sample substrate, 110.11
1,206,310,311...Gas inlet, 112
,209,312...exhaust system,113.305...
Magnetic field generator, 201... cathode electrode, 202...
-Anode electrode, 203...Third electrode, 204...
High frequency power supply, 208...Sample substrate heating heater

Claims (1)

[Claims] A thin film deposition apparatus comprising a plasma generation chamber having means for introducing a gas to be activated and a means for introducing microwaves, and a film deposition chamber having means for introducing a gas containing a main component element of the deposited film. A magnetic field generating device composed of a solenoid coil is installed on the outer periphery of the film deposition chamber, and means is provided for scanning the magnetic field of the film deposition chamber in a direction parallel to the surface of the substrate on which the film is deposited. Thin film deposition equipment using microwave plasma CVD method.