JPH0788583B2 - Plasma reactor - Google Patents

Description

The present invention relates to a plasma reactor used in a semiconductor manufacturing process.

[Prior Art] Conventionally, in an etching process or a deposition (deposition film formation) process in a semiconductor manufacturing process, a high electric field is applied to a required gas introduced into a depressurized reaction vessel to generate a plasma by glow discharge. There is used a plasma reaction apparatus configured to perform etching or deposition by utilizing a chemical reaction of active ions or radicals generated by the decomposition of gas in the plasma.

As an example of this plasma reactor, an electron cyclotron resonance (electron
A cycrotron resonance (ECR) plasma etching apparatus is known. That is, in this ECR plasma etching apparatus, the microwave M is introduced into the plasma generation chamber 1 under reduced pressure into which the gas G such as CF ₄ gas is introduced to generate plasma, and a magnetic field is applied to this to cause ECR. Thus, the plasma density is increased, and the densified plasma is introduced into the reaction chamber 2 to etch the semiconductor wafer W mounted on the sample table 3. In FIG. 2, reference numeral 4 is an inlet for gas G, 5 is an outlet of the reaction chamber 2 connected to a vacuum exhaust system (not shown), 6 is a magnetic coil, and 7 is a microwave waveguide. The tube, 8 is a microwave introduction window.

[Problems to be Solved by the Invention]

By the way, in the etching by the plasma reactor of the conventional configuration, the temperature of the ions (or radicals) generated in the plasma becomes high, and high-energy ions with a wide energy distribution are generated, so that the processing accuracy is deteriorated or the semiconductor There is an inconvenience that the wafer W is damaged.

The present invention has been devised in view of such inconvenience, it is possible to generate low energy ions having a good energy distribution, and it is possible to improve the etching characteristics for a semiconductor wafer, It is an object of the present invention to provide a plasma reactor having a structure that can be used for deposition of semiconductor wafers.

[Means for Solving the Problems]

The present invention, in order to achieve such an object, He gas
A reaction chamber filled with etching gas or deposition gas, equipped with a plasma generation chamber that generates He ions or radicals by ECR and generates He ions or radicals, and a sample stage set to a predetermined negative potential, and a plasma generation chamber and reaction chamber. A local evacuation chamber disposed between the plasma generation chamber and He ions or radicals introduced from the plasma generation chamber through the ion introduction slit of the local evacuation chamber excites the etching gas or deposition gas in the reaction chamber to generate excitation. It is characterized in that a semiconductor wafer mounted on a sample table is etched or deposited by ions.

[Action]

According to the above means, He gas with a light mass and generally difficult to ionize is introduced into the plasma generation chamber before ECR
Since it is turned into plasma by, He ions or radicals having a very high energy level are generated.
Then, since such He ions or radicals are introduced to excite the etching gas or deposition gas filled in the reaction chamber, the excited ions generated from these gases have a good energy distribution and are low energy ions. Becomes

At this time, the etching gas or deposition gas diffused from the reaction chamber is discharged to the outside through the local vacuum exhaust chamber.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional view showing a schematic configuration of a plasma reactor according to an embodiment of the present invention. In this figure, parts and portions which are the same as or correspond to those in FIG. 2 showing the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted here. In the following description, the semiconductor wafer W will be etched using this plasma reactor.

The plasma reactor according to this embodiment includes a plasma generating chamber 1 and a reaction chamber 2 which are separated from each other, and a local vacuum exhaust chamber 10 is provided between them. Then, an inlet 4 for introducing the He gas G1 into the plasma generation chamber 1
Is installed in the plasma generation chamber 1
He ions or radicals are generated by converting the He gas G1 introduced from the above into plasma by ECR.

Further, the reaction chamber 2 is provided with an inlet 11 for introducing a required etching gas G2, and an etching gas G2 such as Cl ₂ gas introduced from the inlet 11 is provided in the reaction chamber 2. It is full. The pressure inside the reaction chamber 2 is reduced by a vacuum exhaust system (not shown) to which the exhaust port 5 is connected. Furthermore, this reaction chamber 2
A sample table 3 for mounting a semiconductor wafer W and rotating is provided on the side wall of the sample table 3 via an insulating member 13, and a constant voltage source 14 for setting the sample table 3 to a predetermined negative potential is provided. It is connected. That is, the sample table 3 is set to be floating from the ground potential, and the semiconductor wafer W to be processed is mounted on the surface thereof. The reason why the sample table 3 is set to a negative potential is to improve the processing accuracy during etching.

On the other hand, the local evacuation chamber 10 communicates with the plasma generation chamber 1 and the reaction chamber 2 through the ion introduction slits 15 formed in the upper and lower walls of the local evacuation chamber 10, and the vacuum evacuation system (illustrated in FIG. Not) connected to. Therefore, the etching gas G2 diffused from the reaction chamber 2 to the local vacuum exhaust chamber 10 is sucked by the vacuum exhaust system, so that the separation between the reaction chamber 2 and the plasma generation chamber 1 is ensured.

That is, in the plasma reactor according to the present embodiment, the He gas introduced into the plasma generator 1 is ECR
Since it is turned into plasma by, He ions or radicals having a very high energy level are generated.
Then, an etching gas G such as Cl ₂ gas filled with He ions or radicals and filled in the reaction chamber 2
Since it excites 2, it is easy to remove C from this etching gas G2.
Excited ions such as l ₂ ions are generated, the energy distribution of the generated excited ions becomes good, and the energy becomes low.

By the way, in the present embodiment, the plasma reactor having the above configuration is used for etching the semiconductor wafer W.
It is needless to say that the present invention is not limited to this and can be applied to the deposition of the semiconductor wafer W. That is, the plasma generation chamber 1 that constitutes this plasma reactor
He gas is introduced into the reaction chamber 2 while deposition gas such as N ₂ and SiH ₄ gas is introduced into the reaction chamber 2 so that a Si ₃ N ₄ film or the like is formed on the surface of the semiconductor wafer W. A deposited film having excellent characteristics is formed.

〔The invention's effect〕

As described above, the plasma reaction apparatus according to the present invention includes the plasma generation chamber and the reaction chamber, and the local vacuum exhaust chamber arranged between them, and has a very high energy level generated in the plasma generation chamber. High He ions or radicals are introduced through the ion introduction slit of the local vacuum exhaust chamber, and the etching gas filled in the reaction chamber is excited, so the excited ions generated from these gases have a good energy distribution, and Become low-energy ions. Therefore, unlike the conventional example, the processing accuracy of the semiconductor wafer is not deteriorated or the semiconductor wafer is not damaged, and an excellent effect that the etching characteristics of the semiconductor wafer can be significantly improved is obtained. To be

Since the etching gas diffused from the reaction chamber at this time is released to the outside through the local vacuum exhaust chamber, the etching gas cannot enter the plasma generation chamber.

Further, by using the gas introduced into the reaction chamber as the deposition gas, there is an effect that the plasma reaction device according to the present invention can be used for the deposition of the semiconductor wafer.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a schematic configuration of a plasma reaction apparatus according to an embodiment of the present invention, and FIG. 2 is a vertical sectional view showing a schematic configuration of a plasma reaction apparatus according to a conventional example. In the figure, reference numeral 1 is a plasma generation chamber, 2 is a reaction chamber, 3 is a sample stage, G1 is a helium (He) gas, G2 is an etching gas, and W is a semiconductor wafer. In addition, the same reference numerals in the drawings indicate the same or corresponding parts and portions.

Claims (2)

[Claims] 1. A reaction in which a helium (He) gas is plasmatized by electron cyclotron resonance to generate He ions or radicals, and a sample stage set to a predetermined negative potential, and which is filled with an etching gas. Chamber and a local evacuation chamber located between the plasma generation chamber and the reaction chamber, and He gas or radicals introduced from the plasma generation chamber through the ion introduction slit of the local evacuation chamber excites the etching gas in the reaction chamber. Then, the plasma reaction apparatus is characterized in that the semiconductor wafer mounted on the sample stage is etched by the generated excited ions. 2. A deposition gas is filled with a plasma generation chamber for generating helium (He) gas into plasma by electric cyclotron resonance to generate He ions or radicals and a sample stage set to a predetermined negative potential. It is equipped with a reaction chamber and a local vacuum exhaust chamber that is located between the plasma generation chamber and the reaction chamber.Deposition gas in the reaction chamber is generated by He ions or radicals introduced from the plasma generation chamber through the ion introduction slit of the local vacuum exhaust chamber. A plasma reaction apparatus, wherein a semiconductor wafer mounted on a sample stage is deposited by exciting excited ions.