JP2000269141A - Plasma treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve uniformity of film formation, while simplifying the upper structure of the inside of a reaction chamber. SOLUTION: A plasma CVD device has a gas ring for supplying treatment gas from the periphery of a wafer W, arranged in parallel inside a reaction chamber 1 toward the center of the wafer. Two gas rings 25, 45 for supplying the same treatment gas into the reaction chamber 1 are arranged coaxially: one is the main gas ring 25 and the other is the supplementary gas ring 45 for correcting irregularities of film formation by the main gas ring 25. When viewed in the circumferential direction, the positions of nozzles 25a, 45a of the gas rings 25, 45 is set so that the nozzle 45a of the supplementary gas ring 45 is positioned in the middle of the nozzle 25a of the main gas ring 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plasma processing apparatus such as a plasma CVD apparatus used in a semiconductor manufacturing process or an LCD manufacturing process.

[0002]

2. Description of the Related Art As one of semiconductor manufacturing processes, plasma CVD (Chemical Chemistry) for forming a predetermined film on a wafer (substrate to be processed) is performed.
ical Vapor Deposition) There is a film forming process. In this method, a wafer is placed in a reaction chamber held in a vacuum, and high-frequency power is applied to a discharge coil while supplying a reaction gas to a nozzle provided in the reaction chamber to generate plasma. And causes a chemical reaction to form a thin film on the wafer surface.

Usually, film formation is performed while maintaining a constant pressure in a reaction chamber by an automatic pressure controller using feedback control (not shown). Plasma CVD shown in FIG.
In the apparatus, the reaction chamber 1 is composed of a lower structure 2 and an upper ceramic dome (dielectric dome) 3, and a turbo molecular pump 5 is provided in the lower structure 2.

[0004] Inside the reaction chamber 1, there is provided an electrostatic chuck 6 for holding and fixing a wafer, which also serves as an electrode for bias application, and the wafer W can be arranged on the electrostatic chuck 6. Monosilane (SiH
₄ ) The gas shower plate 15 placed on the ceiling of the ceramic dome 3 and the nozzle 25 of the first gas ring 25
a, oxygen (O ₂ ) is supplied from the nozzle 35 a of the second gas ring 35 into the reaction chamber 1. The arrangement of the nozzle 25a and the nozzle 35a is as shown in FIG. That is, the nozzles 25a and 35a of both gas rings 25 and 35 are 90
Four are arranged at equal intervals in the circumferential direction,
The position of the nozzle 35a of the second gas ring 35 is shifted by 45 degrees with respect to the nozzle 25a of the first gas ring 25. That is, when viewed from above, the nozzle 25a and the nozzle 35
a are alternately arranged at intervals of 45 degrees in the circumferential direction.

The gas shower plate 15 is connected to a monosilane gas supply pipe 17 having a gas flow controller 16. Further, the first gas ring 25 and the second gas ring 35 are arranged so as to be sandwiched between the joints between the lower structure 2 and the ceramic dome 3 so that gas can be blown toward the center of the wafer W. Has become. The first gas ring 25 is connected to a gas supply pipe 27 for monosilane provided with a gas flow control device 26, and the second gas ring 3
5 is connected to a gas supply pipe 37 for oxygen provided with a gas flow controller 36. Therefore, the same monosilane gas shower plate 15 and first gas ring 25 include:
Gas can be supplied at an independent flow rate by a separate system. In addition, each gas flow control device 16, 26, 36
Are mass flow controllers (MFC) 16a, 26
a, 36a and the valves 16b, 16c, 26 before and after it.
b, 26c, 36b, and 36c.

A coil 9 connected to a high frequency power supply 10 is arranged around the ceramic dome 3.
By inductively applying a high frequency to the reaction gas introduced into the reaction chamber 1 by the coil 9, high-density plasma is generated even at a low pressure (1 Pa) so that a predetermined film can be formed on the wafer W. It has become.

This apparatus further has a lower electrode 7 provided with a water-cooled jacket below the electrostatic chuck 6, and supplies 13.56 MHz high-frequency power to the lower electrode 7.
The plasma generated by the coil 9 is drawn onto the wafer W to realize sputter deposition.

[0008] This plasma CVD apparatus is distinguished from a parallel plate type plasma CVD apparatus.
lasma) -called a CVD apparatus. This device is S
A gas used for embedding STI (Shallow Trench Isolation) or gap fill with an iO2 film is SiH ₄ , O ₂ , or Ar. Ar is used to increase the sputtering effect, and by increasing the sputtering effect, the coverage of a fine pattern is improved.
However, at the same time, the film formation rate is reduced, so that adjustment with the sputtering effect is important.

By the way, when a film is actually formed by using the above-described apparatus, the film formation distribution becomes as shown in FIG. 6, and if the distance between the nozzles of the gas rings 25 and 35, especially the nozzle 25a of SiH ₄ is wide, It can be seen that there is a place where the film thickness falls. FIG. 6 is a film thickness contour line, and a thin portion indicated by T corresponds to a position between the nozzles 25a.

As described above, experiments have shown that the phenomenon that the film thickness becomes thinner at a position distant from the nozzle 25a occurs, but this does not necessarily mean that it is sufficient to reduce the interval between the nozzles. For example, when the number of nozzles is increased by narrowing the interval between the nozzles, the amount of gas flowing out from each nozzle decreases, and the film thickness at the central portion of the wafer tends to decrease. Therefore, in order to correct the film thickness in this portion, in the above-described apparatus, the gas shower plate 15 is disposed above the ceramic dome 3, and the gas is also supplied from the gas shower plate 15.

[0011]

However, when the gas shower plate 15 is arranged on the upper part to improve the uniformity of the film thickness, the upper structure in the reaction chamber 1 becomes complicated,
It also includes the possibility of generating particles.

In consideration of the above circumstances, the present invention solves the complexity of the structure by adjusting the nozzle interval and introducing a gas for complementing the film thickness uniformity from above the dome, and secures uniform film formation with a simple structure. It is an object of the present invention to provide a plasma processing apparatus capable of performing the following.

[0013]

According to the present invention, there is provided a plasma processing apparatus having a gas ring for supplying a processing gas from a periphery of a substrate to be processed horizontally disposed in a reaction chamber toward a center of the substrate to be processed. Two gas rings for supplying the same processing gas into the reaction chamber are coaxially arranged, one is a main gas ring, and the other is a complementary gas ring for correcting non-uniformity of film formation by the main gas ring. The position of the gas ejection hole of the complementary gas ring is shifted from that of the gas ejection hole. Although the gas ejection hole may be a simple hole or a nozzle, it is preferable to provide a nozzle as compared with a case where a hole is simply provided, because the uniformity of the film thickness is further improved.

In this apparatus, the non-uniformity of the film thickness when the processing gas is blown out from the gas discharge holes of the main gas ring to form a film can be corrected by blowing out the processing gas from the complementary gas ring. By shifting the position of the gas ejection holes, the film thickness uniformity is improved.Furthermore, when viewed in the circumferential direction, when the gas ejection holes of the supplementary gas ring are located at approximately the middle position of the gas ejection holes of the main gas ring. Further, good film thickness uniformity can be obtained.

Further, even if the interval between the gas ejection holes of the main gas ring is not narrowed, the processing gas is supplied from the supplementary gas ring to the portion where the film thickness becomes thin (the portion corresponding to the space between the gas ejection holes of the main gas ring). Can be supplied, and a drop in film thickness can be eliminated.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a plasma CVD apparatus shown as a plasma processing apparatus of the embodiment.

In this plasma CVD apparatus, no gas shower plate is provided on the ceiling of the ceramic dome 3,
Instead, three-stage gas rings 25, 35, and 45 are provided so as to be sandwiched between the joints between the ceramic dome 3 and the lower structure 2. The first and second gas rings 25 and 35 in the lower two stages perform almost the same function as the conventional one, and the third gas ring 45 disposed at the top is a new gas ring instead of a gas shower plate. It is provided in. The other basic structure is the same as that of the conventional example shown in FIG. 4, so that the same elements are denoted by the same reference numerals and description thereof will be omitted.

First, second, and third gas rings 25, 3
Numerals 5 and 45 are arranged coaxially, and both are arranged so as to blow out gas from the nozzles 25a, 35a and 45a toward the center of the wafer W. The reason why the nozzles 25a, 35a, and 45a are provided instead of the mere holes is that the nozzles have more uniform film thickness. The first gas ring 25 is a main gas ring for blowing out monosilane, the third gas ring 45 is a complementary gas ring for blowing out monosilane, and the second gas ring 35 is a gas ring for blowing out oxygen.

As shown in FIGS. 2 and 3, each gas ring 2
5, 35, and 45 have gas flow controllers 26,
Independent gas supply pipes 27, 3 equipped with 36, 46
7, 47 are connected. Although the two gas supply pipes 27 and 47 for monosilane are originally connected to one main pipe, the flow rates of the gas rings 25 and 45 can be controlled independently of each other. . The third
Similarly, the gas flow control device 46 of the gas ring 45 includes a mass flow controller (MFC) 46a and valves 46b and 46c before and after the mass flow controller (MFC).

The complementary third gas ring 45 is for correcting non-uniform film formation when the film is formed only by the first gas ring 25 which is the main gas ring.
The first nozzle 45a is positioned at a position between the four nozzles 25a of the first gas ring 25,
On the gas ring 25. That is, the nozzles 25a, 45 of the first and third gas rings 25, 45
a are provided at equal intervals in the circumferential direction at intervals of 90 degrees, and four nozzles a are provided.
a, the nozzle 45a of the third gas ring 45
The position is shifted by 5 degrees. Therefore, when viewed from above, the nozzles 25a and the nozzles 45a are alternately arranged at intervals of 45 degrees in the circumferential direction. Further, a second gas ring 35 for supplying oxygen is provided.
Position of the nozzle 35a of the two gas rings 25,
It is set so as to deviate from the position of the 45 nozzles 25a and 45a.

As described above, the nozzle 2 of the main gas ring 25
Since the nozzle 45a of the supplementary gas ring 45 is disposed where the film thickness drops due to the large interval of 5a, the drop in the film thickness can be complemented and the film thickness in the wafer surface can be made uniform.

In this case, the two gas rings 25, 45 have separate gas supply pipes 27, which can control the flow rate independently.
Since the connection 47 is connected, the flow rate of the supplementary gas ring 45 is controlled in accordance with the degree of the decrease in the film thickness, whereby uniform film formation can be achieved with high accuracy.

The nozzle 45 of the complementary gas ring 45
By adjusting the length of a, the range in which the film thickness can be covered can be widened.

In the above embodiment, the main gas ring 2
In order to adjust the flow rate of the gas blown out from the gas ring 5 and the supplementary gas ring 45, the gas supply pipes 27 and 47 of different systems were connected, but the nozzles 25a and 45 of the gas rings 25 and 45 were connected.
By making the hole diameter of a different, even if the gas is supplied from a single gas supply pipe, the flow rate of the blown gas can be made different. For example, the gas flow rate can be controlled by setting the hole diameter of the nozzle 45a of the supplementary gas ring 45 to half the hole diameter of the nozzle 25a of the main gas ring 25.

[0025]

As described above, according to the present invention,
To correct unevenness in film thickness when film formation is performed by blowing processing gas from the gas outlet of the main gas ring by blowing processing gas from a newly provided supplementary gas ring instead of a gas shower plate. And the uniformity of film formation can be improved. Further, if the positions of the gas ejection holes of the main gas ring and the gas ejection holes of the supplementary gas ring are shifted, the film thickness uniformity is further improved. Furthermore, since the gas shower plate can be eliminated from the upper part of the reaction chamber, the upper structure in the reaction chamber can be simplified,
Eliminating gaps and steps reduces the generation of particles.

[Brief description of the drawings]

FIG. 1 is a sectional view of a plasma CVD apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view showing a configuration of each gas ring in the same device.

FIG. 3 is a perspective view showing a configuration of each gas ring in the device.

FIG. 4 is a sectional view of a conventional plasma CVD apparatus.

FIG. 5 is a plan view showing a configuration of each gas ring in the same device.

FIG. 6 is a diagram showing film thickness contour lines when a film is formed by the same apparatus.

[Explanation of symbols]

 W Wafer (substrate to be processed) 1 Reaction chamber 25 First gas ring (main gas ring) 45 Third gas ring (complementary gas ring) 25a, 45a Nozzle

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G075 AA24 BC04 BD01 BD14 CA25 CA47 DA02 EB01 EC01 FB01 FC13 4K030 AA06 AA14 CA12 EA05 EA06 FA01 FA04 KA20 5F045 AA08 AB32 AC01 AC11 BB02 BB15 EE04 EE12 EF04 EF08 E08

Claims (1)

[Claims] 1. A plasma processing apparatus having a gas ring for supplying a processing gas from a periphery of a substrate to be processed horizontally disposed in a reaction chamber toward a center of the substrate to be processed, wherein the same processing gas is introduced into the reaction chamber. Two gas rings to be supplied are arranged coaxially, one is a main gas ring, and the other is a supplementary gas ring for correcting non-uniformity of film formation by the main gas ring, and a gas ejection hole of the main gas ring and a supplementary gas A plasma processing apparatus, wherein the position of a gas outlet of a ring is shifted.