JPH03107481A - Plasma treating device - Google Patents

Abstract

PURPOSE:To uniformize a plasma distribution and to execute the plasma treatment uniformly at a high speed by enclosing the side between a counter electrode and a substrate electrode with a deposition preventive plate, ejecting gas from the ejection ports formed in the counter electrode and providing an annular discharge passage around the substrate electrode. CONSTITUTION:The etching gas is ejected from the ejection ports of the counter electrode 5 to a space 21. An electric current is passed to an inner electromagnet 18 and an outer electromagnet 19 to form axisymmetrical magnetic fields around the central axis of the substrate electrode 6. The high density plasma of the etching gas is formed in the space 21 when a high-frequency electric power is impressed from an RF power source 17 to the substrate electrode 6. The products generated by the etching and the etching gas which does not contribute to the etching are discharged through the annular discharge passage 23 around the substrate electrode 16 and are discharged through the clearance 28 with a baffle 27 of an annular chamber 25 from a discharge port 2. The space 21 is enclosed axisymmetrically by the deposition preventive plate 22 and the stable discharge is generated therein.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a plasma processing apparatus used as a dry etching apparatus, a plasma CVD apparatus, an ashing apparatus, and the like.

(Prior Art) Conventionally, as shown in FIGS. 1 and 2, in an etching chamber a, a flat counter electrode at an anis potential and a flat substrate electrode d connected to an RF power source C are connected to each other. A single-wafer type etching apparatus is known in which a counter electrode f is provided with a number of jetting ports arranged in parallel and jetting etching gas toward a substrate e to be etched, which is provided in front of the substrate electrode d.

The substrate electrode d is attached to the etching chamber a via a spacer shield g, and the substrate e is carried into the etching chamber a from the outside via a partition valve h. In this apparatus, after the etching chamber a is evacuated from the exhaust port i, a gas introduction valve j is opened to eject etching gas from the counter electrode, and high-frequency power is applied to the upstream substrate electrode d of the RF power source. When the etching gas is applied, the high-frequency power turns the etching gas into a plasma state between the picture electrodes and d, and the substrate e is etched by the activated ions and radicals. It is discharged from the exhaust port i. k is an annular adhesion prevention plate, I
is a sensor port where an emission spectrum monitor, vacuum gauge, etc. are installed.

Additionally, a magnetron etching device is known in which a magnet is provided behind the substrate electrode to generate a magnetic field in front of the substrate electrode (Japanese Patent Laid-Open No. 57-IL4935). Etching speed is improved because high-density plasma is generated in front of the substrate electrode.

Furthermore, there is also known a method in which a magnet is provided not behind the substrate electrode but behind the counter electrode, and high-density plasma is generated in front of the counter electrode, aiming at uniform etching of the substrate (Japanese Patent Application Laid-Open No. 1989-81). -43427).

Furthermore, in sputtering equipment, behind the target,
It has also been proposed to control film formation by providing a double ring-shaped electromagnet inside and outside (Japanese Patent Laid-Open No. 61-162866).

(Problem to be solved by the invention) In recent years, dry processes have been progressing in microfabrication for manufacturing highly integrated semiconductor devices, and etching, CVD
Processes that use plasma are increasingly being used for ashing, etc., and single-wafer processing, in which substrates are processed one by one, is used to improve etching characteristics such as pattern control accuracy, reproducibility, and uniformity. is increasingly being carried out. In order to improve the efficiency of this single leaf processing,
Speeding up plasma processing is essential.

Although a magnetic field can be used to speed up plasma processing, it has been extremely difficult to make the plasma distribution uniform by controlling only the magnetic field. The cause of this is, as shown in Figs. 1 and 2, the etching chamber a of the plasma processing equipment.
A vacuum processing chamber such as the one shown in FIG. It is necessary to form an opening m, and it is also necessary to form an opening m at a location corresponding to the exhaust port i of the adhesion prevention plate and the transfer port j of the substrate, and these openings m This is thought to be caused by the fact that when high-frequency power is applied to the substrate electrode d, the potential distribution becomes uneven, or the gas flow becomes uneven, resulting in local concentration of plasma. In this case, the in-plane uniformity of the substrate becomes extremely poor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma processing apparatus that can uniformize plasma distribution and perform plasma processing on a substrate quickly and uniformly.

(Means for Solving the Problems) In the present invention, a disk-shaped counter electrode at ground potential or float potential and a disk-shaped substrate electrode connected to an RF power source are provided in parallel with each other in a vacuum processing chamber. , in which a large number of jetting ports for ejecting gas toward the substrate provided on the surface of the substrate electrode are formed on the surface of the counter electrode, an annular axially symmetrical ring with double inner and outer layers is provided on the back of the counter electrode. An electromagnet is provided, the side of the space sandwiched between the counter electrode and the substrate electrode is surrounded by an annular adhesion prevention plate that prevents plasma diffusion, and the jet ports formed on the counter electrode surface are arranged axially symmetrically. The above object is achieved by forming an annular exhaust passage between the substrate electrode and the adhesion prevention plate.

In a preferred configuration of the present invention, an opening/closing opening for substrate transfer and/or a honeycomb-shaped small hole are formed in a part of the adhesion prevention plate, and the substrate electrode is provided so as to be able to move toward and away from the counter electrode. It will be done.

(Operation) A substrate is placed on the substrate electrode in the vacuum processing chamber, gas is ejected in a shower form from the outlet of the counter electrode, and an electromagnet behind the counter electrode is energized to generate a magnetic field in front of the counter electrode. In this state, connect the substrate electrode with l? Apply F power. As a result, the gas becomes a high-density plasma between the counter electrode and the substrate electrode even if the pressure inside the vacuum processing chamber is on the order of 10'' torr, and ions, radicals, etc. generated in the plasma rush into the substrate. The surface is etched or ashed, or a gas activated in plasma is attached to the surface of the substrate to form a thin film by CVD. Products and excess gas generated during etching or ashing are exhausted to the outside through the exhaust port.

Behind the counter electrode, an annular axially symmetrical electromagnet with two layers inside and outside is provided, so that the magnetic field distribution on the surface of the counter electrode has central axis symmetry, and the distance between the counter electrode and the substrate electrode is By surrounding the sides of the space between them with anti-adhesive plates, stable discharge can be obtained without causing abnormal discharge, and gas is uniformly blown out from the ejection ports arranged axially symmetrically on the opposing electrode, and the anti-adhesive plate connects to the substrate electrode. Since the exhaust gas is discharged from the annular exhaust passage between the substrates, the gas flow is not unevenly distributed, and evenly distributed plasma can be generated between the two electrodes, resulting in plasma processing with good in-plane uniformity of the substrate. can be done.

(Embodiment) To explain the case where the embodiment of the present invention is applied to the etching apparatus shown in FIGS. 3 and 4, the reference numeral (1) in these drawings is an exhaust port ( 2) and a substrate transfer port (4) equipped with a partition valve (3) that can be opened and closed.
(5) and (6) are circular vacuum processing chambers (5) and (6) having disk-shaped counter electrodes and substrate electrodes which are provided in parallel with each other at a distance above and below the vacuum processing chamber (1). show.

The counter electrode (5) is grounded or floated, and its surface is covered with an insulating surface electrode material (7) such as quartz, alumina, anodized aluminum, etc., and a spacer shield (8) is placed on the counter electrode (5).
) is attached to the vacuum processing chamber (1) via a gas pipe (IQ) equipped with a valve (9) for introducing gas outside the vacuum processing chamber (1) on the surface side of the counter electrode (5) A recess av to be connected is provided.A large number of jet ports (2) communicating with the recess (G1) are formed in the surface electrode material (7) in an axially symmetrical manner, and the gas is introduced via a gas pipe (a). The etching gas to be etched passed through a porous gas inlet buffer (131) provided in the recess (11) and was uniformly blown out from the ejection port (+21).

Further, the substrate electrode (6) is attached to a spacer shield (
+5), a surface electrode material qe of an insulating material such as quartz is applied to the surface of the substrate electrode (6), and a vacuum processing chamber (
1) External I? P power supply a7).

(18G9) is the inner and outer 2 provided behind the counter electrode (5).
A heavy annular axially symmetrical electromagnet with an inner electromagnet (18
A yoke [phase] is provided between the inner and outer electromagnets ae (191) and the outer periphery of the outer electromagnet (+91), so that the current to each electromagnet aa agl can be controlled separately.

A space sandwiched between the counter electrode (5) and the substrate electrode (6) ■
The side of the electrode (5) (ω) is surrounded by an anti-adhesion plate (■) made of insulating material such as anodized aluminum in an annular shape, and the picture electrode (5) (ω) and the anti-adhesion plate (2) are divided into the vacuum processing chamber (1). circular space■
An annular exhaust passage (■) is formed between the substrate electrode (6) and the adhesion prevention plate (■), and the gas in the space (■) is exhausted to the outside from the exhaust port (2) via the exhaust passage (■). It was to so.

(2) is the outer circumferential shield of the substrate electrode (6), which is attached to the vacuum processing chamber (1) by appropriate means. The gas from within the space σ passes through the exhaust passage (■), flows into the annular chamber (■) formed around the outer periphery of the platform aΦ of the vacuum processing chamber (1), and is exhausted from the exhaust port (2). A plurality of screens ■, which can be moved up and down by loosening the screws ■ shown in Figures 5 and 6, are installed inside the chamber ■, and the gaps between the tips of the screens ■ and the wall of the vacuum processing chamber (1) are By adjusting (2), approximately the same amount of exhaust air is emitted from locations near and far from the exhaust port (2).

The part of the anti-adhesion plate (■) corresponding to the substrate transfer port (4) is constructed with an opening/closing plate Q attached to a lifting device ω introduced from outside the vacuum processing chamber (1), and the substrate (■) to be plasma processed is partitioned. Open the valve (3) and insert the substrate electrode (
6) When carrying in or out, when the opening/closing plate (■) is lowered by the lifting device ω, an opening/closing opening (■) for transportation is formed in the anti-adhesion plate (■), through which the substrate (■) can be taken in and taken out. During the plasma treatment, the opening/closing port (2) was closed to equalize the distance between the substrate electrode (6) and the adhesion prevention plate, thereby making the potential distribution uniform.

The situation during plasma processing in the space
) It is necessary to measure with a vacuum gauge, an end point detector to detect the end point of etching, or a film thickness meter installed at the sensor port ■ of the etching plate ■. Adhesion prevention plate ■ with a through hole ■ formed in the location corresponding to the sensor port ■ of the attachment plate ■, and a large number of small holes ■ with a hole diameter of 3 mm or less in a honeycomb shape that does not allow plasma etc. to pass through. Insert the sensor port cover ■ made of the same material as the sensor port ■ so that the situation inside space 0 can be measured through the small hole ■, maintain the axial symmetry of the anti-adhesion plate ■, and prevent abnormal discharge inside space 0. This makes it possible to perform stable discharge without any problems.

To explain its operation, the partition valve (3) and opening/closing port■
After opening the opening and carrying the substrate ■ onto the substrate electrode (6) from the outside, and closing the partition valve (3) and opening and closing port ■, the inside of the vacuum processing chamber (1) is evacuated from the exhaust port (2), and gas is introduced. The etching gas is ejected from the ejection port aD of the counter electrode (5) into the space (1) in the form of a shower, and the inside of the vacuum processing chamber (1) is adjusted to a level of 10-'torr. Then 4A to the inner electromagnet aε, 7A to the outer electromagnet (+9)
When a current of When is applied to the substrate electrode (6), a high-density plasma of etching gas is formed in the space Q.The etching gas is ionized into ions and radicals in the plasma, and these rush into the substrate The substrate (2) is etched at high speed. The products generated by etching and the etching gas that did not contribute to the etching pass through the annular exhaust passage (2) around the substrate (1) electrode ae, and are removed from the gap between the annular chamber (1) and the screen (2). (2) is exhausted to the outside from the exhaust port (2).

The space (■) is surrounded by the anti-adhesion plate (■) axially symmetrically, and there are no openings that would affect the plasma or disturb the potential distribution of the substrate electrode (6). ,
A stable discharge occurs, and the etching gas flows uniformly from the axially symmetrical jet ports (121) of the counter electrode (5).
It flows into the annular exhaust passage (2), does not disturb the plasma distribution, and as shown by curve B in FIG. 8, the substrate (2) can be etched with good uniformity and at high speed. Curve C in FIG. 8 is the in-plane etching distribution of the substrate when etching is performed using the conventional apparatus shown in FIG.

By flowing an ashing gas through the gas pipe 00, uniform ashing can be performed on the substrate (2), and by flowing a CVD gas, a uniform film can be formed on the substrate (2) by plasma CVD.

Figure 9 shows the placement of the substrate electrode (6) in the vacuum processing chamber (1).
2. It can be raised and lowered by a lifting means to freely approach and move away from the counter electrode (5). In this case, the substrate transfer port (4) is provided at a location corresponding to the lowered position of the substrate electrode (6). , it becomes unnecessary to have an opening/closing opening for loading/unloading the board (2) as shown in the third figure on the adhesion prevention plate (2).

GD is Earth Shield.

(Effects of the Invention) As described above, the plasma processing apparatus of the present invention has an annular axially symmetrical electromagnet with double inner and outer layers behind the counter electrode. is surrounded by an axially symmetrical adhesion-prevention plate, and the gas is ejected from the axially symmetrical nozzles formed on the opposing electrode, and an annular exhaust passage is provided around the substrate electrode, making the gas flow uniform. At the same time, the discharge is stabilized, the plasma distribution is made uniform, and the substrate can be subjected to high-speed plasma processing with good uniformity.

[Brief explanation of drawings]

Fig. 1 is a cut side view of a conventional plasma processing apparatus, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, Fig. 3 is a cut side view of an embodiment of the plasma processing apparatus of the present invention, and Fig. 4 5 is a sectional view taken along the IV-IV line and v-v line in FIG. 3, and FIG.
FIG. 7 is a horizontal magnetic field distribution diagram on the substrate electrode, FIG. 8 is an in-plane etching distribution diagram of the substrate, and FIG. 9 is a cut side view of another embodiment of the present invention. It is a diagram. (1)...Vacuum processing chamber (6)...Substrate electrode (171...RF power source...Space...Exhaust passage (to)...Small hole (5)... Counter electrode ■... Ejection port aε (Ig)... Electromagnet... Anti-adhesive plate ■... Opening/closing mouth patent application filed by Akira Kitamura of Hito Nippon Vacuum Technology Co., Ltd. - Other 3 daughters

Claims (4)

[Claims] 1. In a vacuum processing chamber, a disk-shaped counter electrode at ground potential or float potential and a disk-shaped substrate electrode connected to an RF power source are provided in parallel with each other, and a gas is directed toward the substrate provided on the surface of the substrate electrode. In the case where a large number of ejection ports are formed on the surface of the counter electrode, a double ring-shaped axially symmetrical electromagnet is provided behind the counter electrode, and the electromagnet is sandwiched between the counter electrode and the substrate electrode. The side of the space is surrounded by an annular adhesion prevention plate that prevents plasma diffusion, the ejection ports formed on the opposing electrode surface are arranged axially symmetrically, and an annular exhaust gas is provided between the substrate electrode and the adhesion prevention plate. A plasma processing apparatus characterized in that a passage is formed. 2. 2. The plasma processing apparatus according to claim 1, wherein a part of the adhesion prevention plate is provided with an opening/closing opening for transporting the substrate. 3. In order to measure the state in the space sandwiched between the counter electrode and the substrate electrode from the outside of the deposition prevention plate, a honeycomb-shaped small hole was formed in a part of the deposition prevention plate to an extent that did not allow plasma to diffuse. The plasma processing apparatus according to claim 1, characterized in that: 4. 2. The plasma processing apparatus according to claim 1, wherein the substrate electrode is provided so as to be able to move toward and away from the counter electrode.