JPH093622A - Device for forming thin film - Google Patents

Abstract

PURPOSE: To provide such a device for forming a thin film as is capable of uniformity in the film thickness. CONSTITUTION: The device is provided with a vacuum chamber 2, substrate holder 4 installed in this vacuum chamber 2, gas flow adjusting plate 6 which is provided with a gas inlet part 8' for introducing a reaction gas over the substrate holder 4 and which is faced parallelly with the substrate holder 4, and a ring-shaped gas cup 7 for forming a circumferential wall separating the circumference of a space 14 between the substrate holder 4 and the gas flow adjusting plate 6. Thus, the device is designed to form a satisfactory film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film forming apparatus used for manufacturing semiconductor devices and various sensors.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional example (JP-A-2-236283). That is, a substrate holder 53 heated by a heater 52 is arranged in a vacuum chamber 51 that is evacuated by a vacuum pump 50, and a substrate 54 to be formed with a film is fixed to the surface of the substrate holder 53. . Then, a space between the substrate holder 53 and the gas flow control plate 55 surrounds the substrate holder 53 and the gas flow control plate 55 together with a coolable gas cup 56, and a reaction gas from the gas cup 56 to the enclosed space. And a gas nozzle 57 for introducing

The gas flow control plate 55 and the gas cup 56 are formed in a hollow shape, and cooling water is flown inside,
These are cooled. Reference numerals 58 and 59 are insulators, 60 is a high frequency power source, and 61 is a matching circuit.

[0004]

However, in this conventional example, when supplying a reaction gas having a short life or supplying a highly reactive reaction gas, the gas supplied from the gas nozzle 57 of the gas cup 56 is In many cases, the reaction occurs in the space where it goes out, and in many cases, the gas that cannot use the carrier gas cannot reach the center of the substrate 54. As a result, there is a drawback that the film thickness of the substrate 54 is not uniform.

Therefore, an object of the present invention is to provide a thin film forming apparatus capable of achieving uniform film thickness.

[0006]

A thin film forming apparatus according to a first aspect of the present invention includes a vacuum chamber, a substrate holder installed in the vacuum chamber, and a gas introducing section for introducing a reaction gas onto the substrate holder. And a ring-shaped gas cup that forms a peripheral wall that partitions the space between the substrate holder and the gas flow adjusting plate.

According to a second aspect of the present invention, in the thin film forming apparatus according to the first aspect, at least one of the gas flow adjusting plate and the gas cup is rotatable about an axis parallel to the opposing direction of the substrate holder and the gas flow adjusting plate. It is configured in. The thin film forming apparatus of claim 3 is the same as that of claim 1.
Alternatively, in claim 2, a high frequency voltage can be applied to at least one of the gas flow adjusting plate and the substrate holder.

[0008]

According to the thin film forming apparatus of the first aspect, the reaction gas is introduced from the gas introducing portion into the space formed by the substrate holder, the gas flow adjusting plate and the gas cup, and the surface of the substrate holder is formed by the gas phase chemical reaction. A film is formed on the substrate provided on the substrate. In this case, since the gas was introduced from the gas introduction part of the gas flow adjusting plate, the easily reacting gas reacts near the surface of the substrate, resulting in a significant improvement in the film thickness uniformity, which was not obtained before. Membranes become possible.

According to the thin film forming apparatus of the second aspect, in the first aspect, at least one of the gas flow adjusting plate and the gas cup is provided around an axis parallel to the opposing direction of the substrate holder and the gas flow adjusting plate. Since it is configured to be rotatable, in addition to the function of claim 1, the gas is agitated in the space, so that the gas flow can be improved and the film thickness can be made more uniform.

According to the thin film forming apparatus of claim 3, since the high frequency voltage can be applied to at least one of the gas flow adjusting plate and the substrate holder in claim 1 or 2, Claim 2
In addition to the above action, the reaction on the substrate provided on the substrate holder is rate-determining, and low temperature film formation becomes possible.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIG.
That is, this thin film forming apparatus is a CVD apparatus that introduces a reaction gas between the substrate holder 4 and the gas flow adjusting plate 6 which are arranged in parallel in the vacuum chamber 2 to form a film on the substrate 5. is there. In such a thin film forming apparatus, in this embodiment, the gas cup 7 and the gas flow adjusting plate 6 are provided with the gas introducing portions 8 and 8 ', respectively, and the gas cup 7 and the gas flow adjusting plate 6 are formed by known means. It is configured to be rotatable (not shown) around an axis parallel to the opposing direction of the two.

The gas cup 7 is a ring-shaped peripheral wall which is arranged at the peripheral portions of the substrate holder 4 and the gas flow adjusting plate 6 and partitions the space 14 between the substrate holder 4 and the gas flow adjusting plate 6. Is formed. In this gas cup 7, one end in the ring-shaped axial direction, that is, the opposing direction of the gas cup 7 and the gas flow adjusting plate 6 is rotatably slidably contacted to the peripheral edge portion of the gas flow adjusting plate 6 via the insulator 23, and the other end. Is a gap 26 between the substrate holder 4 and
Is formed. In addition, a heating means 15 is provided inside the gas cup 7 as a heater for heating the gas cup 7.

Further, the gas introduction portion 8 of the gas cup 7 is arranged near the peripheral portion of the gas flow adjusting plate 6 so that the space 1
4, the reaction gas is introduced, but penetrates the vacuum chamber 2 and the gas cup 7, and its discharge port is directed to the inner surface of the gas cup 7. The gas flow adjusting plate 6 also serves as a high-frequency electrode, is formed in a hollow shape, and has an opening in the surface facing the substrate holder 4 for discharging gas, which is provided in the vacuum chamber 2. Protruding portion 6 that rotatably penetrates through the insulator 22 and protrudes to the outside
a, and the gas introducing portion 8'is provided on the protruding portion 6a. Further, a heating means 21 such as a heater is provided inside the gas flow adjusting plate 6.

Further, the gas flow adjusting plate 6 together with the gas cup 7 is configured so as to be freely movable toward and away from the substrate holder 4,
Therefore, the gas flow adjusting plate 6 is attached to the gas cup 7
With this displacement, the size of the gap 26 can be changed to adjust the pressure of the space 14 surrounded by the gas cup 7, and the distance between the gas flow adjusting plate 6 and the substrate holder 4 can be adjusted. It is possible to adjust.

Reference numeral 1 is a vacuum pump for evacuating the vacuum chamber 2, 3 is a heater for heating the substrate holder 4, 24 is a matching circuit connected to the protrusion 6a of the gas flow adjusting plate 6, and 25 is a matching circuit 24. It is a connected high frequency power supply. In this thin film forming apparatus, the inside of the vacuum chamber 2 is evacuated by the vacuum pump 1, so that the inside of the gas cup 7 is evacuated through the gap 26 to reduce the pressure. In addition, the reaction gas is discharged from the gas introduction portions 8 and 8 ′ toward the inner side surface of the gas cup 7 and the upper surface of the substrate 5, and a film is deposited on the surface of the substrate 5 by the gas phase chemical reaction of the reaction gas. The gas diffused in the space 14 is exhausted through the gap 26.

Further, when a high frequency voltage is applied between the substrate holder 4 and the gas flow adjusting plate 6 from the high frequency power source 25 through the matching circuit 24, it is guided to the space 14 from the discharge port of the gas introducing section 8. Discharge of the reaction gas occurs, plasma is generated, the reaction gas is ionized and undergoes a gas phase chemical reaction,
A film is deposited on the surface of the substrate 5. The gas pressure in the space 14 surrounded by the gas cup 7 can be adjusted by displacing the gas cup 7 together with the gas flow adjusting plate 6 to change the size of the gap 26, and thereby the film formation rate can be improved. Adjustments are made. In addition, the high frequency electrode 6
The optimum condition for forming a uniform film over the entire surface of the substrate 5 is set by adjusting the distance between the substrate holder 4 and the substrate holder 4.

In the thin film forming apparatus having the above-mentioned structure, since the gas is introduced from the gas introduction portion 8'of the gas flow adjusting plate 6, the easily reacting gas reacts near the surface of the substrate 5, so that the film thickness is uniform. The property is greatly improved, and it is possible to form a good film that has not been obtained in the past. Further, when the gas flow adjusting plate 6 and the gas cup 7 are configured to be rotatable about an axis parallel to the facing direction of the substrate holder 4 and the gas flow adjusting plate 6, the gas is agitated in the space 14, so that the gas flow is improved. Therefore, the film thickness can be made more uniform.

Furthermore, when a high frequency voltage is applied to the gas flow adjusting plate 6, the reaction on the substrate 5 provided on the substrate holder 4 is rate-determined and low temperature film formation becomes possible. The high frequency voltage may be applied to the substrate holder 4 or may be applied to both the gas flow adjusting plate 6 and the substrate holder 4 to obtain the same effect as the above. Further, a gas introduction part 8 is provided near the edge of the gas flow adjustment plate 6 of the gas cup 7, and the discharge port of this gas introduction part 8 is provided by supplying high-frequency power between the gas flow adjustment plate 6 and the substrate holder 4. Since it is directed to the side opposite to the space 14 where the plasma is generated, it is possible to prevent a film from being formed at this discharge port, and therefore, the gas introduction part 8 is not clogged.

Moreover, it is the gas flow adjusting plate 6, the gas cup 7 and the substrate holder 4 that face the space 14 in which plasma is generated outside the substrate 5 which is the film formation target portion. Since the heating means 15 for heating is provided, the film adhesion can be reduced by heating the gas cup 7. Further, since the gas flow adjusting plate 6 is heated by the heating means 21, it is effective when supplying the gas of the liquid material, and reduces film adhesion to the gas flow adjusting plate 6 when supplying the high frequency power, Dirt can be reduced.

Using such a thin film forming apparatus, a film was formed on the substrate 5 under a predetermined film forming condition and the film thickness uniformity of the substrate 5 was measured. That is, the substrate 5
Is 4 inches of A1 ₂ O ₃ (alumina), the film forming vacuum degree is 0.6 Torr, and the gas flow rate is 50 SCCM (bubbler temperature 20 ° C.), TMG (bubbled N ₂ amount)
H ₃ is set to 50 SCCM and a GaN film is formed on the substrate 5. Here, TMG trimethyl gallium, bubbling N ₂ amount in N ₂ blowing N ₂ in TMG liquid TMG
The amount of hump is the amount of steam on which the bubbler temperature is TMG.
This is the temperature that controls the vapor pressure of.

In this case, in Example 1, the film forming temperature was 100.
The temperature is set to 0 ° C., and NH ₃ is supplied from the gas introduction part 8 of the gas cup 7,
TMG was supplied from the gas introduction part 8 ′ of the gas flow adjusting plate 6. Further, since the gas is a liquid material, the gas cup 7 and the gas flow adjusting plate 6 are connected to the heating means 15, 21.
Heated by. The film formation result shows that the film formation rate is 2 μm / H,
The film thickness uniformity was ± 5%, and the crystallinity was a single crystal.

Here, as a comparison with the example, the film forming results were measured for the conventional example in which the conditions were the same as in the example 1 and all the gas was supplied from the gas introduction part 8 of the gas cup 7. As a result, the film formation rate was 1 μm / H, the film thickness uniformity was ± 10%, and the crystallinity was single crystal. Example 2 is
The film forming condition is that the film forming temperature is 800 ° C., the gas cup 7 is rotated at a rotation speed of 60 rpm, and the rotation speed of the gas flow adjusting plate 6 is 1000 r, as compared with the first embodiment.
Only pm is different. The results of film formation are a film formation rate of 2.5 μm / H, film thickness uniformity of ± 3%, and crystallinity of a single crystal.

In the third embodiment, as compared with the first embodiment, the film forming condition is that the film forming temperature is 300 ° C., and the high frequency power is 20 W.
The only difference is that (13.56 MHz) was supplied to the gas flow adjusting plate 6. The film formation result is 1 μm /
H, the film thickness uniformity was ± 5%, and the crystallinity was polycrystalline. Therefore, the film forming speed, the film thickness uniformity, the crystallinity, and the film forming speed are shown in the table below. Film formation speed (μm / H) Film thickness uniformity (±%) Crystallinity Film formation temperature (° C.) Conventional example 1 10 Single crystal 1000 Example 1 2 5 Single crystal 1000 Example 2 2.5 3 Single crystal 800 Implementation Example 3 15 Poly-Crystalline 300 From this table, in all of Examples 1 to 3, the film thickness uniformity was improved and the film formation rate was improved as compared with the conventional example, and when the high frequency power was supplied, the results were obtained. It can be seen that the film temperature can be lowered.

The gas introduction portion 8'of the gas cup 7 is 1
However, when supplying various gases, a plurality of gas introduction parts may be installed. Further, although both the gas cup 7 and the gas flow adjusting plate 6 are rotated, only one of them may be rotatable.

[0025]

According to the thin film forming apparatus of the first aspect of the present invention, since the gas is introduced from the gas introduction part of the gas flow adjusting plate, the easily reacting gas reacts near the surface of the substrate, so that the film thickness uniformity is greatly improved. The effect is that it is possible to form a good film that has not been obtained conventionally.

According to the thin film forming apparatus of claim 2, in claim 1, at least one of the gas flow adjusting plate and the gas cup is provided around an axis parallel to the opposing direction of the substrate holder and the gas flow adjusting plate. Since it is configured to be rotatable, in addition to the effect of claim 1, the gas is agitated in the space so that the gas flow can be improved and the film thickness can be made more uniform.

According to the thin film forming apparatus of claim 3, since the high frequency voltage can be applied to at least one of the gas flow adjusting plate and the substrate holder in claim 1 or 2, Claim 2
In addition to the above effect, the reaction on the substrate provided on the substrate holder is rate-determining, which enables low-temperature film formation.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 2 vacuum chamber 4 substrate holder 5 substrate 6 gas flow adjusting plate 7 gas cup 8, 8'gas introduction part

Claims (3)

[Claims] 1. A gas flow adjusting plate facing a substrate holder in parallel with a vacuum chamber, a substrate holder installed in the vacuum chamber, and a gas introducing section for introducing a reaction gas onto the substrate holder. And a ring-shaped gas cup that forms a peripheral wall that partitions a space between the substrate holder and the gas flow adjusting plate. 2. The thin film forming apparatus according to claim 1, wherein at least one of the gas flow adjusting plate and the gas cup is configured to be rotatable about an axis parallel to the facing direction of the substrate holder and the gas flow adjusting plate. 3. The thin film forming apparatus according to claim 1, wherein a high frequency voltage can be applied to at least one of the gas flow adjusting plate and the substrate holder.