JP2001077085A - Sample surface treatment method - Google Patents

Abstract

(57) Abstract: To meet the demand for high-speed semiconductor devices, when performing processing such as etching on an organic low-dielectric-constant material, (CH3) 2 O , (NH
2) To provide a method for surface treatment of a sample in which etching treatment is performed with CO or CH3NH2 gas. A sample surface treatment apparatus for processing a fine pattern by plasma etching, comprising: a vacuum container;
A sample stage 108 for mounting a sample 107 to be subjected to surface treatment is provided in 104, processing gas supply means 100 for continuously supplying a processing gas for generating plasma into the vacuum container, Plasma generating means for generating plasma in the
Independently of the plasma generation, a device comprising a bias power supply for applying a bias voltage to the sample stage is used to apply (CH3) 2O, (NH2) C to the sample placed on the sample stage.
A surface treatment method for a sample in which a process such as etching is efficiently performed with O or CH3NH2 gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for surface treatment of a sample, and more particularly to a surface treatment method suitable for etching an organic low dielectric constant film using plasma.

[0002]

2. Description of the Related Art Conventionally, as means for treating the surface of a semiconductor device, an apparatus for etching a semiconductor device in plasma has been known. Here, a conventional technique will be described using an apparatus called an ECR (Electron Cyclotron Resonance) method as an example. In this method, plasma is generated by microwaves in a vacuum vessel to which a magnetic field is externally applied. Electrons move in a cyclotron due to the magnetic field, and a plasma can be generated efficiently by resonating this frequency with the frequency of the microwave. A high frequency voltage is applied to the sample to accelerate ions incident on the sample such as a semiconductor device. Further, a halogen gas such as chlorine or fluorine is used as a process gas to be plasma.

In such a conventional apparatus, a material mainly subjected to etching processing is a metal such as resist, polysilicon, and Al, and an oxide film. However, with an increase in the speed of a semiconductor device, an example of using an organic low dielectric constant film instead of an interlayer insulating film is increasing. A mixed gas of H2 and N2 has been reported as a gas used for etching with an organic low dielectric constant.

[0004]

By the way, with the miniaturization of semiconductor elements, the processing dimensions of lines and spaces corresponding to wirings and electrodes are in the region of 0.5 μm or less, preferably 0.2 μm or less. When etching an organic low-dielectric-constant film, in processing such a fine pattern, the line becomes gradually thicker, and the problem that the pattern cannot be processed to design dimensions becomes significant. Further, in addition to the difference in etching rate between a fine groove and a relatively wide portion, a difference in shape, that is, a so-called shape microloading becomes remarkable, which hinders processing. In addition, when etching an organic low dielectric constant film, there is an example in which a method of generating high-density plasma is adopted in order to improve an etching rate. Or a sub-trench at the bottom of the groove, which hinders subsequent processes.

Although the etching of an organic low dielectric constant film is a new technique, an etching apparatus which has been conventionally used for etching an insulating film is often diverted. The conventional etching apparatus was invented when the minimum processing size of the element was about 1 μm, and the etching material was also a metal material for wiring, a material such as polycrystalline silicon, or the like. In particular, the etching of the organic low dielectric constant film has not been conventionally performed, and the gas used for the etching itself is completely different from the gas used for the conventional etching. Also, in the processing of the organic low dielectric constant film, the etching characteristics are almost equal to the resist used as a mask material,
It is difficult to increase the selectivity. As a result, it is necessary to assemble precise process conditions based on the analysis of the relationship between the physical quantity of the plasma and the etching characteristics, and many manufacturers are currently spending much effort here.

An object of the present invention is to provide a method for treating a surface of a sample, which can efficiently perform a process such as etching of an organic low dielectric constant material.

[0007]

In order to achieve the above object, in the process of etching an organic low dielectric constant film, a plasma is generated in a processing chamber and the organic low dielectric constant film is formed by (CH3) 2O, (NH2) Processing such as etching is performed with CO or CH3NH2 gas.

As a result, the organic low dielectric constant film is changed into the form of CHN, H 2 O, etc. by the etching treatment, and is exhausted. In this etching using (CH3) 2O, (NH2) CO or CH3NH2, the generation of bowing and subtrench can be reduced because the etching gas contains C.

According to the present invention, in processing a fine pattern, (CH3) 2O, (NH2) CO or CH3NH2
When a process such as etching is performed with a process gas having the above-mentioned characteristic, the use of a gas containing C can reduce the occurrence of bowing and sub-trench. This makes it possible to uniformly and uniformly form an etched shape on the entire surface of the sample on which processing such as etching is performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. FIG. 1 is an overall configuration diagram of a plasma etching apparatus to which the present invention is applied. Microwaves are introduced into the vacuum chamber 104 from the magnetron 101 via the automatic matching unit 106, the waveguide 102, and the introduction window 103.
On the other hand, an etching gas such as halogen is introduced into the vacuum vessel 104 via the gas introduction means 100, and plasma of this gas is generated with the introduction of the microwave. The material of the introduction window 103 is a material that transmits microwaves (electromagnetic waves) such as quartz and ceramic.

An electromagnet 105 is provided around the vacuum vessel 104.
Is installed. The magnetic field strength of the electromagnet 105 is set so as to cause resonance with the frequency of the microwave. For example, if the frequency is 2.45 GHz, the magnetic field strength is 875 Gauss.

At this magnetic field strength, the cyclotron motion of the electrons in the plasma resonates with the frequency of the electromagnetic wave, so that microwave energy is efficiently supplied to the plasma,
High-density plasma can be generated.

The sample 107 is set on a sample stage 108. In order to accelerate ions incident on the sample, an rf (radio frequency) bias power supply 109 which is a high frequency power supply
Are connected to the sample stage 108 via a high-pass filter 111.

A DC power supply 112 is connected via a low-pass filter 113, and a voltage is applied to the sample stage 108, whereby the sample is held on the sample stage by electrostatic force.

In FIG. 1, the generated plasma is (CH
3) Of 2O, (NH2) CO or CH3NH2,
It contains at least one gas. As a result, it is possible to increase the coefficient of the surface reaction of the sample 107 on which the processing such as etching is performed. In sample 107, (C
The portion of the organic low dielectric constant film etched by H3) 2O, (NH2) CO or CH3NH2 is changed to CHN, H2O, or the like and evacuated. As a result, etching can be performed while controlling the etching shape of the sample.

FIG. 2 shows a comparison of side wall shapes when etching is performed with (CH3) 2O, (NH2) CO or CH3NH2 gas, and when etching is not performed. FIG. 2 relates to the improvement of the bowing shape. That is, (CH3) 2
When etching is performed with O, (NH2) CO or CH3NH2 gas, the side wall shape of the sample is good, and no shape defect such as bowing is observed. However, when etching is performed using a mixed gas of H 2 and N 2, since a gas having a depot property is not used, the side wall shape of the sample is etched, so that the groove has a bowing shape.

[0017]

According to the present invention, it is possible to provide a method for treating a surface of a semiconductor device, which enables an organic low-dielectric-constant film to be efficiently subjected to a treatment such as etching.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an etching apparatus according to an embodiment of the present invention.

FIG. 2 is an etching shape diagram in the etching of the present invention.

[Explanation of symbols]

100: gas introduction tube, 101: microwave power supply, 102: waveguide, 103: introduction window, 104: vacuum vessel, 105: magnet, 106: stub tuner, 107: sample, 108: sample stage, 109: high frequency voltage Power supply, 111 matching box, 112 DC power supply, 113 low-pass filter, 115 plasma, 116 resist
117: oxide film, 118: organic low dielectric constant film.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Katsuya Watanabe 502 Kandachi-cho, Tsuchiura-shi, Ibaraki F-term in Machinery Research Laboratory, Hitachi, Ltd. F-term (reference) 5F004 AA05 BA14 BB11 DA00 DB23 EB03

Claims (2)

[Claims] 1. A plasma generator, an etching chamber capable of reducing pressure, a gas supply device for supplying a gas to the etching chamber, a sample table for holding a sample to be subjected to plasma processing, and a sample table supported on the sample table. In a sample surface treatment method using a device for applying a high frequency to a sample and a plasma treatment device including a vacuum evacuation device and the like, when etching an organic low dielectric constant film, (CH3) 2O, (NH2) CO or C
A method for treating a surface of a sample, wherein at least one kind of gas is used among H3NH2. 2. The organic low dielectric constant film according to claim 1, wherein at least one of (CH3) 2O, (NH2) CO and CH3NH2 is mixed with another gas. A surface treatment method for a sample, characterized by performing a treatment such as etching on the sample.