JPH0244720A - Microwave plasma treatment device - Google Patents

Abstract

PURPOSE:To uniformly process a wafer having a large diameter by providing a plurality of microwave waveguides disposed relatively to a central position planely in parallel with a substrate to be treated from the side of a plasma generation chamber, disposing a magnet in a microwave inlet, and simultaneously irradiating them with microwaves. CONSTITUTION:4 microwave waveguides disposed relatively to a central position in a two-dimensional manner are provided in parallel with a substrate to be treated from the side of a polygonal plasma generating chamber 30 to the microwave generating chamber 30, and ringlike magnets M3-M6 are fitted to the inlets of the waveguides. Since magnetic field gradients (Miller magnetic field) are laterally generated from the four waveguides toward the center of the chamber 30 and longitudinally generated, even if the waveguides are laterally disposed, a wafer can be etched. Thus, the uniform magnetic field of large capacity is formed, and a wafer having a large diameter can be etched or grown uniformly and accurately in dimension.

Description

[Detailed Description of the Invention] [Summary] Regarding the improvement of microwave plasma processing equipment such as microwave plasma etching, a plasma generation chamber provided above a substrate to be processed is provided for the purpose of uniformly processing large diameter wafers. For,
from the side of the plasma generation chamber in parallel to the substrate to be processed,
In addition, a plurality of microwave waveguides are provided that are arranged relative to the center position in a plane, and a magnet is arranged in a portion where the microwaves are introduced from the plurality of microwave waveguides. The configuration is such that microwaves are simultaneously irradiated from the microwave waveguides.

In addition, one or more magnets are arranged to generate a magnetic field perpendicular to the substrate to be processed.

[Industrial Field of Application] The present invention relates to microwave plasma processing equipment such as microwave plasma etching, and particularly relates to improvement of plasma processing equipment for higher performance.

As a process technology for semiconductor manufacturing, dry processing has become a very important technology for miniaturization and high integration of semiconductor devices, and plasma processing using microwaves has recently been widely used, for example, for silicon substrates, It is used in the etching process of resist films and polycrystalline silicon films. This microwave (2.45 GH2) plasma processing has the advantage of higher excitation efficiency than conventional plasma processing using high frequency (13°56 MH2).

However, it is desired that such processing apparatuses be improved to cope with the increase in the size of substrates to be processed such as wafers.

[Prior art] Microwave plasma processing equipment connects a microwave power source and a plasma generation chamber with a waveguide. Generally, a method is adopted in which microwave power is introduced vertically into a plasma generation chamber through a microwave transmission window, and is irradiated vertically onto a wafer (substrate to be processed) placed in the plasma processing chamber. Here, the microwave-transmitting window is a window that transmits only microwaves while vacuum-sealing the inside of the plasma processing chamber, and quartz or alumina is considered to be a suitable material.

Figures 6(a) and 6(b) show schematic diagrams of conventional microwave plasma etching equipment. window, 3 is a plasma generation chamber, 4 is a plasma etching chamber, 5 is a wafer, 6 is a stage, 7 is a reaction gas inlet, 8 is an exhaust port, Ml, M2 are ring-shaped magnets.For example, in the plasma etching chamber 4 to 10' to 1
The vacuum level is 0-'Torr, and the magnet is old.

M2 forms a magnetic field as shown in Fig. 6 fb). The vertical axis of FIG. 6(b) is the distance, and the length corresponds to the dimension of FIG. 6(b) (al).

Due to the magnetic field gradient shown in Fig. 6, electrons are accelerated in the direction where the magnetic field becomes weaker (toward the wafer).
The wafer receives the electrons and charges up. Then, the electric field generated between the plasma potential and the wafer (
Ions are attracted to the wafer by the potential difference (potential difference), and an etching reaction occurs due to the ions.

[Problems to be Solved by the Invention] Now, when performing ECR (Electron Cyclotron Resonance) etching with low damage and good dimensional control using such a microwave plasma etching apparatus, for example, when the plasma source is TE1)3 mode, when the microwave frequency is 2.45 GH2, the inner diameter of the plasma source (plasma generation chamber) is limited to about 20 cIT1 from the point of view of excitation efficiency, and there is a problem that even if it is made larger than that, there is a large loss.

Therefore, in the conventional method as described above, the plasma source (plasma generation chamber) is small, and a large diameter wafer, for example, an 8-inch diameter wafer cannot be etched uniformly over the entire surface.

The present invention solves these problems and proposes a microwave plasma processing apparatus aimed at uniformly processing a large diameter wafer surface.

[Means for Solving the Problems] The purpose is to generate a plasma in a plasma generation chamber provided above a substrate to be processed, from the side of the plasma generation chamber parallel to the substrate to be processed and two-dimensionally. A plurality of microwave waveguides are provided relative to the center position, and a magnet is provided at a portion where microwaves are introduced from the plurality of microwave waveguides. This is accomplished by a microwave plasma processing device configured to simultaneously irradiate microwaves.

Further, one or more magnets are arranged to generate a magnetic field perpendicular to the substrate to be processed.

[Operation] That is, the present invention forms horizontal and vertical magnetic fields by a magnet with good controllability, allows electrons to reach the wafer, charges amplifies them, and directs ions to the wafer by the electric field between the plasma generation chamber and the evaporator. to cause an etching reaction. In this way, by introducing multiple microwaves from the side, the problem of restricting the area of the plasma generation chamber depending on the frequency of the microwaves is alleviated, and it becomes possible to generate uniform high-density plasma with a large capacity. Therefore, large diameter wafers can be processed uniformly.

[Example] Hereinafter, embodiments will be described in detail with reference to the drawings.

FIGS. 1(a) and 1(b) show an embodiment (a) showing a plasma generating part of a microwave plasma etching apparatus according to the present invention.
I) Figure 1(a) is a plan sectional view of the plasma generation chamber;
Figure 1 (b) shows the AA cross section of figure fa), and the lower part of Figure 1 (the right side of bl is the magnetic field strength diagram at the longitudinal center of the plasma generation chamber, and the lower part of Figure 1 fb) is the plasma generation chamber. This is a magnetic field strength diagram at the center in the horizontal direction, and the distance between the magnetic field strength diagrams is set to a length that corresponds to the dimension fb) in the same figure. Figure 1(a).

In (b), old, M4. M5. M6 is a ring-shaped magnet.

13, 14.15.16 are microwave waveguides, 23.
24.25° 26 is a microwave transmission window, 30 is a plasma generation chamber, 40 is a plasma etching chamber, 50 is a wafer, 60 is a stage, and 70 is a reaction gas inlet.

That is, in this example, four microwave waveguides are provided for the polygonal plasma generation chamber 30, and a ring-shaped magnet M3. M4゜M5. M6
In this example, as shown in the magnetic field strength diagram,
Since a magnetic field gradient (mirror magnetic field) is generated in the horizontal direction from the four waveguides toward the center of the plasma generation chamber 30, and a magnetic field gradient is generated in the vertical direction, the waveguides are guided in the horizontal direction as shown in the figure. Wafers can be etched even if a tube is installed, and if the magnetic field strength is appropriately selected, uniform high-density plasma can be generated over a wide range, making it possible to evenly etch even large-diameter wafers. can.

Next, FIGS. 2(a) and 2(b) are diagrams of an embodiment (n) showing the plasma generation section of the microwave plasma etching apparatus according to the present invention, and FIG. 2(a) is a plan sectional view of the plasma generation chamber. FIG. 2 fbl shows a BB sectional view of FIG. 2 fa), and a magnetic field intensity diagram similar to FIG. 1 around FIG. 2 fb). The symbol in the figure is M7. M8 is a ring-shaped magnet, and the other symbols are the same parts as in FIG. 1 with the same symbols.

That is, in this example, instead of fitting a magnet into each inlet of the microwave waveguide as in the embodiment shown in FIG. 1, two magnets are placed above and below the plasma generation chamber 30, and the microwave waveguide A magnetic field gradient (divergent magnetic field) is generated from the introduction part toward the lower part of the plasma generation chamber (towards the wafer). In addition, in the magnetic field strength diagram in the horizontal direction of the plasma generation chamber shown in Figure 2 (lower part of BL), contrary to Figure 1, a magnetic field gradient (divergent magnetic field) is formed from the center to the periphery, but this is due to the large diameter wafer. This is to generate a widely uniform high-density plasma corresponding to the etching process.If the gradient of the horizontal magnetic field lines is adjusted appropriately, it is possible to generate a uniform high-density plasma over a wider area than the etching apparatus shown in Figure 1. can be generated and can handle large diameter wafers.

Next, FIGS. 3(a) and 3(b) are diagrams showing an embodiment (I[I) of the plasma generation section of the microwave plasma etching apparatus according to the present invention, and FIG. 3(a) shows the plasma generation chamber. The plan sectional view, Figure 3(b) is the CC sectional view of Figure 3(a), and the area around bl shows the same magnetic field intensity diagram as above. , the same parts as in Fig. 2 are given the same symbols, and the embodiment shown in Fig. 3 combines the magnets shown in Fig. 1 and the magnets shown in Fig. 2. By arranging many magnets, it becomes easy to control the magnetic field distribution, and - it is possible to generate a wide and uniform high-density plasma, and it is possible to generate magnetic fields corresponding to wafers of various sizes.However, Magnet M provided in this example
7°M8 is a magnet that generates only a magnetic field perpendicular to the wafer 50; The adjustment of the magnetic field by M8 is different from the magnetic field generation in the embodiment shown in FIG.

In addition, although all of the above embodiments are provided with four microwave waveguides (microwave power sources), if these microwave waveguides can be arranged relative to each other on a two-dimensional plane, three, Similar effects can be achieved by arranging other quantities of microwave waveguides, such as six.

Next, an example of etching will be described.

FIG. 4 is a schematic diagram of a microwave plasma etching apparatus to which the present invention is applied, and is an apparatus to which the plasma ordering method described in FIG. 3 is applied. The same symbols are attached to the same parts as in FIG. 3, and the remaining numeral 80 is an exhaust port. In addition, the wafer 50 has a bias of 13.56M.
The H2O high frequency power source 80 is applied because this has the advantage of further increasing the etching speed and sharpening the etched shape.

Examples of etching performed using the etching apparatus shown in FIG. 4 are shown in FIGS.
Figure (al) shows an example of forming a three-layer resist film.The thick 0FPR-800 (resist) 52 on the substrate 51 is replaced with the thin 0FPR-800 (resist > 54.5i02 film 5).
This is the process of etching an 8-inch ψ wafer using oxygen as a mask, using oxygen as a reactive gas, micro-power IKW, high-frequency power of 100 W, and gas pressure of 3 x 10' Torr at an etching speed of 5,000 people/man.
It was possible to perform etching with uniformity within ±5%.

Further, FIG. 5(b) shows an example in which a polycrystalline silicon film is etched. A polycrystalline silicon film 55 is deposited on the substrate 51 via a 5i02 film 53, and this is 0FPR.
Etching is performed using -800 (resist) 54 as a mask. Using chlorine as a reaction gas, etching an 8-inch φ wafer at a rate of 4,000 people/man under the conditions of micro-powered IKW, high-frequency power of 10 W, and gas pressure of 8 x 10' Torr.
Etching was possible within ±5% uniformity.

FIG. 5fc) shows an embodiment in which grooves are formed in the substrate.

Enching is performed using 5i02 ff153 on the substrate sl as a mask, and the micro-powered I is etched using chlorine as a reaction gas.
KW, high frequency power 30W, gas pressure 5 x 1.0'T
It was possible to etch an 8-inch φ wafer at an etching rate of 5,000 people/min and with uniformity within ±5% under the conditions of 0.050 or more.

Others: tungsten, aluminum, its alloys, 5i
As a result of etching materials such as 02 film, both ±5
A uniformity within % was obtained.

Although the above embodiment is an example of an etching process, the present invention can be similarly applied to a film growth process to obtain a homogeneous and uniform deposited film.

[Effects of the Invention] As is clear from the above explanation, according to the present invention, the shape of the plasma generation chamber is not determined in order to introduce a plurality of microwaves, and a large-capacity uniform magnetic field cannot be formed. This has the great effect of allowing large-diameter wafers to be uniformly etched or grown with high dimensional accuracy.

[Brief explanation of the drawing]

1(a), (b), FIG. 2(a), (bl) and FIG. 3(a), (b) are views of embodiments (1 to ■) showing the plasma generation section according to the present invention, FIG. 4 is a schematic diagram of a microwave plasma etching apparatus to which the present invention is applied, FIGS. 5(a) to (C) are diagrams showing etching examples, and FIG. 6 is a schematic diagram of a conventional microwave plasma etching apparatus. In the figure, M1 to M8 are magnets, 1.13 to 16 are microwave waveguides, 2.23 to 26 are microwave transmission windows, 3.30 is a plasma generation chamber, 4.40 is a plasma etching chamber, 550 indicates the wafer 6.60 is the stage, 7.70 is the reaction gas inlet, 8.80 is the exhaust port, and 90 is the high frequency power supply. cloud chopsticks P
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Claims (2)

[Claims] (1) With respect to a plasma generation chamber provided above the substrate to be processed, a plurality of plasma generators are arranged parallel to the substrate from the side of the plasma generation chamber and relative to the center position in a plane. A microwave waveguide is provided, and a magnet is disposed at a portion where microwaves are introduced from the plurality of microwave waveguides,
A microwave plasma processing apparatus characterized in that it is configured to simultaneously irradiate microwaves from the plurality of microwave waveguides. (2) The microwave plasma processing apparatus according to claim 1, further comprising one or more magnets that generate a magnetic field perpendicular to the substrate to be processed.