JPS6333574A - Method for opening and closing shutter for controlling plasma flow - Google Patents

Abstract

PURPOSE:To project plasma uniformly and to form a thin film having excellent intra-surface uniformity by rotating a plate shutter which shuts off the flow passage of the plasma flow heading toward a target unidirectionally around the target, thereby opening and closing the shutter. CONSTITUTION:The plasma flow released from a plasma source is bombarded with an adequate energy to a sample 2 on a sample base 1 to form the thin film at an ordinary temp. on the sample 2. At least one panel-shaped shutter 3 which shuts off the flow passage of the plasma flow is disposed orthogonally with said flow passage. Further, the shutter 3 is rotated approximately around the sample 2 in the arrow direction to project the plasma flow to the sample 2 or to stop the projection. The plasma is thereby projected over the entire surface of the sample 2 in an equal time and the intra-surface uniformity of the thin film is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of opening and closing a shutter for plasma flow control.

[Conventional technology]

In recent years, with the rapid development of the semiconductor industry, equipment for semiconductor manufacturing processes has been actively developed. Among them, E
CR (Electron Cyclotron Res)
onance) There is a plasma deposition method. EC
In the R plasma deposition method, highly active plasma generated by an ECR ion source is extracted using a divergent magnetic field, and is made to collide with the sample surface with appropriate energy. As a result, a film formation reaction occurs efficiently on the sample surface due to the combined effect of highly activated plasma and bombardment of ions and electrons. This reaction is characterized by the fact that it does not require external heating, so a high-quality thin film can be obtained at room temperature. On the other hand, g C
The yD method and the plasma CVD method utilize high temperatures and are difficult to use for substrates with low heat resistance or for elements whose functionality and reliability deteriorate when exposed to high temperatures.

Therefore, low-temperature, high-quality thin film production technology is needed for VLSI, LSI
It has been strongly desired to improve the performance of semiconductor devices and increase the yield rate of highly integrated devices. In response to this, the ECR plasma deposition method was developed, and various thin films such as silicon nitride and silicon oxide obtained by this method are acid-resistant and dense, even though they are produced at room temperature without heating. It has been confirmed that it is of high quality, with excellent properties. In such ECR plasma deposition method, control of film thickness,
Improved in-plane uniformity.

The shutter plays a very important role in reproducibility. Conventionally, plasma was generated with the shutter closed, the shutter was opened when the plasma became stable, and the shutter was closed when the deposition was finished.

FIG. 3 shows a sectional view of an example of a thin film manufacturing apparatus.

A microwave waveguide 7 that inputs microwaves is connected to a plasma generation chamber 6 that stores plasma, and an air-core coil 5 is installed around the plasma generation chamber 6 to generate plasma and to Sending out plasma toward the sample 2 in the deposition chamber 8 from the outlet,
Collide with appropriate energy. It has a plate-shaped shutter 3 that stops or releases the flow of plasma. FIGS. 4(a) and 4(b) are a front view and a side view of a mechanism for rotating the shutter shown in FIG. 3. This shutter 3 is fixed to a stepping motor 9 with a support rod 10,
The motor 9 rotates the shutter 3 around the sample 2 and sample stage 1 in forward and reverse directions, thereby controlling the flow of plasma. Figure 5 (a), (b),
(c) is a diagram showing the operation of the conventional shutter 3. FIG. 5(a) shows the state where the shutter 3 is closed,
Sample 2 is placed on sample stage 1. As shown in FIG. 5(b), the shutter 3 is rotated in one direction to apply plasma to the surface of the sample 2. Then, as shown in Fig. 5(c), the shutter 3 is rotated in the opposite direction so that the plasma is transferred to the sample 2.
It has stopped hitting. As can be easily seen from Fig. 5, since the entrance and exit of the shutter 3 is done in one direction (from the lower end), as you go from the lower end of the sample 2 to the upper end,
Sample 2 was exposed to plasma for a long time, so sample 2
The thickness of the upper thin film increased from the lower end to the upper end.

[Problem that the invention seeks to solve]

However, the conventional shutter described above has the following problems. In other words, the conventional shutter is a plate-shaped shutter, and by moving it in a certain direction, plasma begins to flow.When the deposition is completed, that is, when the plasma flow is stopped, the plate-shaped shutter is moved to allow the plasma to flow. I was moving it in the opposite direction from when I started. For this reason, there are parts of the same substrate that are exposed to the plasma for a long time and parts that are not exposed to the plasma for a long time, which poses a problem in terms of uniformity of the film thickness.

An object of the present invention is to provide a method for opening and closing a plasma flow control shutter that can form a uniform thin film within a plane on the same substrate.

[Means for solving problems]

The method for opening and closing a plasma flow control shutter according to the present invention includes at least one plate-shaped shutter that is orthogonal to a flow path through which a plasma flow emitted from a plasma source heads toward a target and blocks the flow path. The method is characterized in that the target is irradiated with the plasma flow and the irradiation is stopped by rotating the target in one direction.

〔Example〕

Next, the present invention will be explained using the drawings.

FIG. 1 (a>, (b), (c), (d) is the first embodiment of the present invention.
FIG. 3 is a schematic diagram showing the example in the order of shutter operation. FIG. 1(a) shows a state in which the shutter 3 is closed. A sample 2 is placed on a sample stage 1. In FIG. 1(b), the shutter is moved to irradiate the sample 2 with plasma. 1st
In Figure (C), the shutter 3 is moved while the deposition is being performed, that is, while the sample 2 is being irradiated with plasma. In FIG. 1(d), the flow of plasma is stopped by moving the shutter 3 in the same direction as when the shutter 3 was opened. In this way, the entire surface of the sample 2 is exposed to the plasma for an equal amount of time, and the in-plane uniformity of the thin film is greatly improved.

FIGS. 2(a), 2(b), and 2(c) show schematic diagrams of a second embodiment of the present invention in which there are two shutters.

In Figure 2 (a), the flow of plasma is stopped by the shutter 3. In Figure 2 (b), the shutter 3 is moved to irradiate the sample 2 on the sample stage 1 with plasma. In (C), shutter 4 is moved in the same direction as shutter 3 to stop the flow of plasma.The uniformity of the thin film is very good for the same reason as mentioned in Figure 1. .Silicon nitride film output 500
W, N225sec M, 5i8415sec M
When the film was deposited for 18 seconds, the film thickness was 100±5% within a 4-inch wafer, and the in-plane uniformity was good at ±5%. Note that when a film was formed using the conventional method under the same deposition conditions, the film thickness was 90 to 130, and the in-plane uniformity was 30% or less. From the above, it can be seen that the shutter of the present invention is very effective in forming a thin film with a thickness of about 100 mm uniformly within the surface.

〔Effect of the invention〕

The in-plane uniformity of the shutter of the present invention is extremely good at ±5% when forming a thin film of about 100 thin films, and compared to the in-plane uniformity of 30% or less obtained by conventional methods. It was also found that the shutter of the present invention is very effective.

[Brief explanation of the drawing]

FIGS. 1(a) to (d) are schematic diagrams showing the first embodiment of the present invention in the order of operation, and FIGS. 2(a) to (c) are schematic diagrams showing the second embodiment of the present invention.
3 is a cross-sectional view of an example of a thin film manufacturing apparatus, FIGS. 4(a) and 4(b) are front and side views of the mechanism for rotating the shutter, and FIG. 5( a) to (c) are schematic diagrams showing the operation of a conventional shutter. 1... Sample stage, 2... Sample, 3... Shutter,
4... Shutter, 5... Air core coil, 6... Plasma generation chamber, 7... Microwave waveguide, 8... Deposition chamber, 9... Stepping motor, 10...
・Support rod. No. i, l-b

Claims (1)

[Claims] By rotating at least one plate-shaped shutter in one direction approximately about the target, the shutter being orthogonal to the flow path of the plasma flow emitted from the plasma source toward the target and blocking the flow path. . A method for opening and closing a shutter for plasma flow control, comprising irradiating the target with the plasma flow and stopping the irradiation.