JPH0551952U - Plasma processing device - Google Patents

Abstract

(57) [Summary] [Objective] To improve the distribution of unreacted gas in a vacuum container and improve the in-batch uniformity and the in-plane uniformity of processing on a substrate. A gas flange 26 is provided on the upper portion of the vacuum container 2, and two gas nozzles 30 are attached to the gas flange 26 symmetrically with respect to the center of the vacuum container 2. The gas 22 is supplied to each gas nozzle unit 30. Each gas nozzle unit 30 is provided with three types of nozzle holes 32 of large, medium and small size, and each nozzle hole 32 is directed to the lower side along the central axis of the vacuum container 2.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a plasma processing apparatus, such as a plasma CVD apparatus or a plasma etching apparatus, which processes a substrate using plasma and uses so-called multi-stage parallel plate electrodes.

[0002]

[Prior Art]

 A conventional example of this type of plasma processing apparatus is shown in FIG. Two electrode support rods 10 are accommodated in a vacuum container 2 which is evacuated from the lower vacuum exhaust port 4 in a vacuum, suspended from an upper lid 6 thereof via an insulator 8. A gas flange 16 having two nozzle holes 18 facing each other in the horizontal direction is provided on the upper portion of the vacuum container 2, and from there, a gas 22 for a CVD source gas or an etching gas is provided in the vacuum container 2 as a gas 22. Are introduced. 20 is a gas introduction pipe.

A plurality of electrode plates 12 are attached to the electrode support rod 10 so as to be superposed alternately and at equal intervals between them in a multi-step manner.

Although not described in detail, a recess is provided on the upper surface of each electrode plate 12, and a substrate (eg, wafer) 14 to be processed is placed on the recess.

A heater 24 that heats each substrate 14 during processing is provided outside the vacuum container 2.

[0006] Explaining an operation example, while evacuating the inside of the vacuum vessel 2, a required gas 22 is introduced into the vacuum vessel 2 to bring the internal pressure into a predetermined range (for example, 10 ^-3 Torr to several tens Torr). When a high frequency voltage is supplied from the high frequency power supply 25 between the electrode supporting rods 10 and 10, it is applied between the odd-numbered electrode plates 12 and the even-numbered electrode plates 12, An electric discharge is generated between the plates 12 and 12 to form a plasma, whereby the gas 22 passes through the vacuum chamber 2 downwards and causes a plasma reaction (a chemical reaction excited by the plasma) in the vicinity of each substrate 14. Then, each substrate 14 is subjected to processing such as film formation and etching. At this time, part of the gas 22 is consumed.

[0007]

[Problems to be solved by the device]

 However, in the conventional multi-stage parallel plate electrode type plasma processing apparatus as described above, there is a problem that the in-batch uniformity and the in-plane uniformity of processing on each substrate 14 are not good. This is because when the gas flange 16 having the two facing nozzle holes 18 as described above is used, the gas 22 is introduced into the vacuum container 2 so as to face in the horizontal direction and collects in the central portion, and then the vacuum is generated. Since the gas 22 flows downward in the container 2, the distribution of the unreacted (ie, not yet consumed) gas 22 in the vacuum container 2 becomes non-uniform in the upper part and the lower part in the vacuum container 2, In addition, since it becomes non-uniform when viewed in the in-plane direction of each substrate 14, it is considered that the cause of the plasma reaction is also non-uniform in the batch and in the plane.

Therefore, the main object of the present invention is to improve the distribution of the unreacted gas in the vacuum container to improve the in-batch uniformity and the in-plane uniformity of the processing on the substrate.

[0009]

[Means for Solving the Problems]

 In order to achieve the above object, the plasma processing apparatus of the present invention introduces the gas into the vacuum container above the vacuum container, and has a size facing the lower side of the vacuum container. A plurality of gas nozzle portions each having a plurality of different nozzle holes are evenly arranged with respect to the center of the vacuum container.

[0010]

[Action]

 According to the above configuration, the plurality of gas nozzles are evenly arranged with respect to the center of the vacuum container, and the gas can be ejected into the vacuum container at different flow velocities from the nozzle holes having different sizes of each nozzle. Therefore, the unreacted gas can be evenly distributed in the vacuum container. As a result, the plasma reaction also becomes more uniform in the batch and in the plane, and the in-batch uniformity and the planar uniformity of the processing on the substrate are improved.

[0011]

【Example】

 FIG. 1 is a sectional view showing a plasma processing apparatus according to an embodiment of the present invention. FIG. 2 is a plan view showing the gas flange in FIG. 1 as viewed from below. The same or corresponding portions as those of the conventional example in FIG. 5 are designated by the same reference numerals, and the differences from the conventional example will be mainly described below.

In this embodiment, the following gas flange 26 is attached to the upper part of the vacuum container 2 instead of the conventional gas flange 16. That is, two gas nozzles 30 are attached to the gas flange 26 symmetrically with respect to the center of the vacuum container 2, and a gas hole 28 in the gas flange 26 communicates with each of them, and the gas nozzle 28 is connected to the gas hole 28. The gas introduction pipes 20 are connected to each other. The gas 22 described above is supplied to the gas introduction pipe 20.

Each gas nozzle portion 30 is, for example, welded to the gas flange 26, but instead of this, it may be bolted to a portion communicating with the gas hole 28 through a packing for sealing. It will be easier to remove.

In this example, each gas nozzle portion 30 is provided with three nozzle holes 32 of three types, large, medium and small, and two nozzle holes 32 in total, six in total. Each nozzle hole 32 communicates with the gas hole 28 of the gas flange 26. Further, the nozzle holes 32 of the two gas nozzle portions 30 are not opposed to each other as in the conventional example, but are all directed to the lower side of the vacuum container 2 and, in this example, along the central axis of the vacuum container 2. ing.

According to the above structure, the two gas nozzles 30 are arranged symmetrically, and the gas 22 is jetted into the vacuum container 2 at different flow velocities from the nozzle holes 32 having different sizes of each gas nozzle 30. Therefore, the gas 22 ejected from the large nozzle hole 32 has a small flow velocity and thus is supplied close to the gas 22, and the gas 22 ejected from the small nozzle hole 32 has a large flow velocity and thus is supplied to a long distance, whereby unreacted (ie The gas 22 (which has not been consumed yet) can be evenly distributed in the vacuum container 2. That is, the unreacted gas 22 can be supplied more uniformly from the upper electrode plate portion to the lower electrode plate portion, and the unreacted gas 22 can be supplied even when viewed in the in-plane direction of each substrate 14. It is possible to supply more uniformly, and as a result, the plasma reaction also becomes more uniform between the upper electrode plate portion and the lower electrode plate portion (that is, within the batch), and the surface of each substrate 14 It is also more uniform in the inward direction, which improves the in-batch uniformity and in-plane uniformity of processing such as film formation and etching on the substrate 14.

An example of the measurement result of the film thickness uniformity when SiN is formed by the plasma CVD method by the apparatus of the embodiment shown in FIG. 1 and the apparatus of the conventional example shown in FIG. And FIG. 4 respectively. The conditions at this time are as follows.

Raw material gas: SiH ₄ 0.3 liter / min NH ₃ 2.0 liter / min Substrate temperature during film formation: 300 ° C. High frequency output: 400 W Vacuum chamber pressure during film formation: 0.5 to 5 Torr

In the conventional example, as shown in FIG. 4, the in-batch uniformity on the substrate was ± 3 to ± 8%, and the in-plane uniformity was ± 3 to ± 6%. As shown in FIG. 3, the in-batch uniformity is ± 2% to ± 4%, and the in-plane uniformity is ± 2% to ± 3%, which are both significantly improved.

The number of nozzle holes 32 provided in the gas nozzle portion 30 is not limited to the number shown in the above example. Further, three or more such gas nozzle portions 30 may be evenly arranged, and by doing so, it becomes possible to further enhance the above-mentioned uniformity.

[0020]

[Effect of the device]

 As described above, according to the present invention, the unreacted gas can be evenly distributed in the vacuum container, so that the plasma reaction also becomes more uniform in the upper and lower parts of the vacuum container. In addition, it becomes more uniform in the in-plane direction of each substrate, thereby improving the in-batch uniformity and the in-plane uniformity of the processing on the substrate.

[Brief description of drawings]

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

FIG. 2 is a plan view showing the gas flange in FIG. 1 as viewed from below.

FIG. 3 is a graph showing an example of a film formation result by the plasma processing apparatus of FIG.

FIG. 4 is a graph showing an example of a film formation result by the plasma processing apparatus of FIG.

FIG. 5 is a sectional view showing an example of a conventional plasma processing apparatus.

[Explanation of symbols]

 2 vacuum container 12 electrode plate 14 substrate 22 gas 25 high frequency power supply 26 gas flange 30 gas nozzle part 32 nozzle hole

Claims (1)

[Scope of utility model registration request] 1. A plurality of electrode plates for mounting substrates, which are stacked in parallel with a space between each other, are housed in a vacuum container in which gas is introduced from the upper part and vacuum is exhausted from the lower part. In the plasma processing apparatus adapted to apply a high frequency voltage between the odd-numbered electrode plate and the even-numbered electrode plate, the gas is introduced into the vacuum container above the vacuum container. The plasma processing apparatus is characterized in that a plurality of gas nozzle portions each having a plurality of nozzle holes of different sizes facing the lower side of the vacuum container are evenly arranged with respect to the center of the vacuum container.