JPH05209278A - Plasma vapor growth device - Google Patents

Abstract

PURPOSE:To reduce unevenness in the thickness of a grown film due to the distortion of a uniform heating plate when process gas is introduced into an airtight chamber and plasma is generated in the chamber to form a thin film on a wafer. CONSTITUTION:A heater is divided into a heater 5 and a heater 11, an automatic temp. regulator 6 and a thermocouple 9 are fitted to the heater 5 and an automatic temp. regulator 12 and a thermocouple 13 are fitted to the hater 11. A mechanism for separately controlling the heaters 5, 11 is disposed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma vapor deposition apparatus (hereinafter referred to as a plasma CVD apparatus), and more particularly to a temperature control mechanism for a substrate to be processed (hereinafter referred to as a wafer).

[0002]

2. Description of the Related Art A cross-sectional view of a conventional plasma CVD apparatus is shown in FIG. 3 (a), and a plan view of its heater portion is shown in FIG. 3 (b).
Shown in. The conventional plasma CVD apparatus includes a chamber 1, a shower electrode plate 2, a holder 3, a soaking plate 4, and a heater A.
5. It is composed of an automatic temperature controller A6. The shower electrode plate 2 is hollow and has a structure in which the process gas introduced from one end is ejected from a small hole opened at the other end. The holder 3 has a disk shape, and a plurality of holes for setting the wafer 7 are formed along the circumference. Further, a holder rotating shaft 8 is attached to the holder 3 so that the holder 3 can be rotated at an arbitrary speed. Also, FIG. 3 (b)
As shown in, a thermocouple A9 is connected to the automatic temperature controller A6, and while the temperature is monitored by the thermocouple A9, the current supplied to the heater A5 is automatically adjusted to bring the wafer 7 to a constant temperature. It is possible to hold.

When performing a film forming operation, first the wafer 7
To the holder 3. At this time, the surface of the wafer 7 is set to face the shower head electrode plate 2, that is, face downward. Next, the inside of the chamber 1 is evacuated using a vacuum pump, and the wafer 7 is heated to about 250 ° C. by the heater A5 while maintaining a reduced pressure state of about 0.35 Torr. Then, when the process gas is caused to flow while rotating the holder 3 and a voltage is applied to the shower head electrode plate 2 using the RF power source 10, plasma is generated between the shower head electrode plate 2 and the holder 3 to cause the process gas to react. Then, a thin film is formed on the wafer 7. S as process gas
If iH ₄ and N ₂ O are used, a plasma oxide film can be formed. Plasma oxide films are often used as interlayer insulating films for semiconductor devices.

[0004]

This conventional plasma C
The VD device has a structure in which a uniform heating plate is heated by one heater, and the wafer is heated by its radiant heat. However, if the same soaking plate is used for a long time, the soaking plate becomes distorted and it becomes impossible to uniformly heat the wafer, so that the temperature distribution in the wafer surface becomes non-uniform and the plasma oxide film grows. In-plane variation in film thickness becomes large. When the in-plane variation of the grown film thickness becomes large, etching failure occurs when performing etching for forming contact holes and the like,
This leads to a reduction in the manufacturing yield of semiconductor devices.

[0005]

Means for Solving the Problems Plasma CVD of the present invention
The apparatus has a heater divided into a plurality of zones, and has a mechanism for independently controlling the heater temperature of each zone.

[0006]

The present invention will be described below with reference to the drawings. FIG. 1A is a sectional view of a plasma CVD apparatus according to a first embodiment of the present invention, and FIG. 1B is a plan view of a heater portion thereof. The plasma CVD apparatus according to this embodiment includes a chamber 1,
Shower electrode plate 2, holder 3, soaking plate 4, heater A
5, heater B11, automatic temperature controller A6, automatic temperature controller B1
It consists of two. The shower electrode plate 2 is hollow and has a structure in which the process gas introduced from one end is ejected from a small hole formed in the surface of the other end. The holder 3 has a disk shape, and a plurality of holes for setting the wafer 7 are opened along the circumference. Further, a holder rotation shaft 8 is attached to the holder 3 so that the holder 3 can be rotated at an arbitrary speed. Further, as shown in FIG. 1B, in the plasma CVD apparatus according to the first embodiment, the heater is divided into a heater A5 and a heater B11 in a ring shape, and an automatic temperature controller A6 and a thermocouple are provided for each heater. A9,
Since the automatic temperature controller B12 and the thermocouple B13 are provided, the inside and the outside of the wafer 7 can be independently heated.

When performing a film forming operation, first the wafer 7
To the holder 3. At this time, the surface of the wafer 7 is set to face the shower electrode plate 2, that is, face downward. Next, the inside of the chamber 1 is evacuated using a vacuum pump, and the wafer 7 is heated to 250 ° C. by the heater 5 while maintaining a reduced pressure state of 0.35 Torr. Then, while rotating the holder 3, the process gas is caused to flow,
When a voltage is applied to the shower head electrode plate 2 using the RF power source 10, plasma is generated between the shower head electrode plate 2 and the holder 3 to cause a reaction of the process gas, and a thin film is formed on the wafer 7. SiH ₄ as the process gas,
A plasma oxide film is formed using N ₂ O.

When the soaking plate is distorted due to long-term use and the in-plane variation of the grown film thickness becomes large, the temperature of the heater in the portion where the grown film thickness is thin is raised to increase the grown film thickness in that portion. Can be thickened. Conventional plasma CVD
In the apparatus, the in-plane variation of the grown film thickness when the soaking plate 4 was distorted was 8%, whereas in the plasma CVD apparatus of this embodiment, the variation was reduced to 5%.

FIG. 2A is a sectional view of a second embodiment of the present invention,
FIG. 2B is a plan view of the heater section. In the second embodiment, the heater is divided into three parts, a heater A5, a heater B11, and a heater C14, and an automatic temperature controller A6 and a thermocouple A9, an automatic temperature controller B12 and a thermocouple B, respectively.
13. Since the automatic temperature controller C15 and the thermocouple C16 are provided, the in-plane temperature distribution of the wafer 7 can be adjusted more accurately. In the plasma CVD apparatus of Example 2,
The in-plane variation of the grown film thickness wafer is reduced to 3%.

[0010]

As described above, the present invention is provided with a heater divided into a plurality of zones, and the temperature of each zone is controlled independently, so that the growth film of the plasma oxide film generated by the distortion of the soaking plate is formed. It is possible to reduce variations in the thickness of the wafer surface. Therefore, there is an effect that it is possible to prevent a reduction in manufacturing yield of semiconductor devices due to etching defects when forming contact holes and the like.

[Brief description of drawings]

1A and 1B are views showing a first embodiment of the present invention, in which FIG. 1A is a sectional view and FIG. 1B is a plan view of a heater portion thereof.

2A and 2B are views showing a second embodiment of the present invention, in which FIG. 2A is a sectional view and FIG. 2B is a plan view of a heater portion thereof.

3A and 3B are views showing a conventional plasma CVD apparatus, in which FIG. 3A is a sectional view and FIG. 3B is a plan view of a heater portion thereof.

[Explanation of symbols]

 1 Chamber 2 Shower Electrode Plate 3 Holder 4 Soaking Plate 5 Heater A 6 Automatic Temperature Controller A 7 Wafer 8 Holder Rotating Axis 9 Thermocouple A 10 RF Power Supply 11 Heater B 12 Automatic Temperature Controller B 13 Thermocouple B 14 Heater C 15 Automatic temperature controller C 16 Thermocouple C

Claims (1)

[Claims] 1. A plasma vapor phase growth apparatus in which a process gas is introduced into an airtight chamber and a plasma is generated therein to form a thin film on a substrate to be processed which is heated by a heater, and is divided into a plurality of zones. A plasma vapor deposition apparatus further comprising a mechanism for independently controlling the heater temperature.