JPH0536640A - Semiconductor manufacturing equipment - Google Patents

Abstract

PURPOSE:To make plasma density in a plasma reaction chamber uniform, in order to improve the uniformity of etch rate in a wafer surface, in a dry etching equipment and the like. CONSTITUTION:A microwave introducing window 110 of a ring type is installed on the wall periphery of a vacuum chamber 105, and a ring type waveguide 108 is arranged so as to surround said window 110. While travelling in the waveguide 108, microwave is gradually coupled with plasma. Thus the plasma is formed in a plasma reaction chamber 101, and a specimen is etched. Since the microwave can be introduced from the whole periphery of the wall surface of the vacuum chamber 105 toward the central part, intensive discharge is obtained in the peripheral part, and the ununiformity of plasma distribution caused by diffusion of plasma toward the wall of the vacuum chamber 105 can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus, and more particularly to a dry etching apparatus for etching using plasma in a semiconductor manufacturing process or a plasma CVD apparatus for forming a film by using plasma. Is.

[0002]

2. Description of the Related Art FIG. 9 is a schematic configuration diagram showing a conventional dry etching apparatus described in, for example, Japanese Patent Laid-Open No. 61-75527. In the figure, 1 is a plasma generating chamber for generating plasma, 5 (5A to 5C) is an ion extracting electrode plate for extracting ions from the plasma in the plasma generating chamber 1 to form a shower-like ion beam, and 6 is a shower-like ion beam. A sample chamber for irradiating the surface of the sample (wafer substrate) 8 with
7 is a sample table on which a sample (wafer substrate) 8 is mounted, 11 is a gas inlet, 12 is an exhaust system for evacuating the sample chamber 6, 13 is a microwave introducing window provided in the plasma generating chamber 1, and 14 is It is a rectangular waveguide for introducing microwaves and is connected to a microwave source (not shown). Reference numeral 15 is a magnetic coil provided on the outer periphery of the plasma generation chamber 1 for generating a magnetic field necessary for causing electron cyclotron resonance.

Next, the operation of the dry etching apparatus will be described. First, the plasma generation chamber 1 and the sample chamber 6 are evacuated, then a Freon-based or chlorine-based reactive gas is introduced from the gas introduction port 11 and set to a predetermined pressure, and a microwave is introduced into the microwave introduction window 13 Introduce more. When the frequency of the microwave is 2.45 GHz, the magnetic coil 15 generates a magnetic field of 875 Gauss necessary for causing electron cyclotron resonance in the plasma generation chamber 1 to generate plasma in the plasma generation chamber 1. After controlling the reactive species by the ion extraction electrode plate 5, the generated plasma is transported to the sample chamber 6 as a shower-like ion beam, and the sample (wafer substrate) 8 is etched.

[0004]

The conventional dry etching apparatus is configured as described above, and some of the plasma generated in the plasma generation chamber 1 is diffused to the side wall surface of the plasma generation chamber 1. Disappear by. Therefore, the plasma density in the peripheral portion is lower than that in the central portion of the plasma generating chamber 1. The energy distribution of the microwaves injected into the plasma reaction chamber 1 is also close to the microwave introduction window, that is, in the center of the plasma reaction chamber because the microwave introduction window 13 is smaller than the inner diameter of the plasma generation chamber 1. It becomes stronger and becomes a factor that makes the plasma density distribution non-uniform. That is, the radial plasma density of the plasma generation chamber 1 is high in the central portion and low in the peripheral portion, resulting in an uneven distribution.
The nonuniformity of the plasma density in the inner diameter direction of the plasma generation chamber 1 is reflected in the density distribution of the reactive species transported on the surface of the sample 8, so that the etching rate in the surface of the sample 8 becomes uneven. .

The present invention has been made in order to solve the above problems, and provides a semiconductor manufacturing apparatus for generating plasma having a uniform distribution density and performing etching or film forming processing with good uniformity. The purpose is to do.

[0006]

A semiconductor manufacturing apparatus according to the present invention is provided with a microwave introduction window for introducing microwaves on a peripheral wall of a plasma reaction chamber, and is arranged so as to surround the microwave introduction window. The microwave is introduced from the annular waveguide through the microwave introduction window, the reactive gas is further introduced, and plasma is generated by electron cyclotron resonance. Further, the microwave can be introduced from a plurality of microwave generators into the annular waveguide. Further, means for matching the microwaves introduced into the plasma reaction chamber was provided.

[0007]

In the semiconductor manufacturing apparatus of the present invention, since microwaves can be introduced from the peripheral wall of the plasma reaction chamber, plasma having a uniform density distribution can be formed in the plasma reaction chamber. Further, since microwaves can be introduced into the annular waveguide from a plurality of microwave generators, plasma with a more uniform density distribution can be formed. Further, by providing the microwave matching means, the coupling between the microwave and the plasma can be finely adjusted.

[0008]

EXAMPLES Example 1. A semiconductor manufacturing apparatus according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of a dry etching apparatus to which this embodiment is applied.
FIG. 2 shows a schematic external view of the dry etching apparatus of FIG. In the figure, 101 is a plasma reaction chamber, 102 is an exhaust port for exhausting the inside of a vacuum chamber 105, 104 is a sample (wafer substrate) placed on a sample stage 103, 106 is a magnetic field generating coil, and 107 is a gas inlet. Is. Reference numeral 110 denotes an annular microwave introduction window provided on the side wall surface of the vacuum chamber 105 in a direction perpendicular to the surface of the sample 104.
It is vacuum sealed with a ring or the like. A microwave transmitting material such as quartz or alumina is used as its material, and its size is almost the same as that of the vacuum chamber 105. Reference numeral 108 denotes an annular waveguide which is attached to the outer periphery of the vacuum chamber 105 so as to surround the annular microwave introduction window 110. In this waveguide 108, an E surface 111 of the illustrated waveguide (a surface parallel to an electric field in the waveguide is called an E surface) is constituted by a part of a wall of the vacuum chamber 105 and a microwave introduction window 110. And transmits microwaves in TE ₁₀ mode. Reference numeral 109 is a microwave generator connected to the annular waveguide 108.

In the dry etching apparatus configured as described above, the inside of the vacuum chamber 105 is evacuated to a predetermined vacuum pressure through the exhaust port 102 by the vacuum exhaust device (not shown), and then the gas introduction port is opened. An etching gas is introduced from 107. Then, the microwave generator 109
When the microwave is operated, the microwave propagates in the annular waveguide 108, and the plasma reaction chamber 101 passes through the microwave introduction window 110.
Is introduced into and discharges the etching gas. At this time, if the intensity of the magnetic field generated by the coil 106 is set to 875 Gauss in the vacuum chamber 105, plasma by electron cyclotron resonance can be formed in the plasma reaction chamber 101. Microwaves propagating in the waveguide 108 are gradually coupled to the microwave introduction window 110 while propagating in the waveguide 108 in an annular shape, and the plasma reaction chamber 1 from the entire circumference of the microwave introduction window 110.
Microwave energy is injected into 01. The combined state of the microwave and the plasma can be adjusted by changing the design of the thickness T of the microwave introduction window 110 in the vertical direction.

By the way, the plasma density distribution in the plasma reaction chamber 101 is generally determined by subtracting the plasma generated by the discharge and the plasma extinguished on the wall surface of the vacuum chamber 105. Since the microwave is injected from the peripheral portion of the plasma reaction chamber 101 toward the central portion, the plasma density generated in this embodiment has a strong distribution in the wall portion of the vacuum chamber 105 and a weak distribution in the central portion. On the other hand, the amount of plasma extinguished depends on the vacuum chamber as described in the explanation of the conventional example.
Increased at 105 walls. As a result, in the plasma reaction chamber 101 according to the present embodiment, a region in which a large amount of plasma is generated and a region in which plasma is extinguished overlap each other, and balance is achieved by canceling them, so that the plasma density distribution is made flat. The above-mentioned balance can be achieved by controlling the microwave power, and plasma with a uniform density distribution can be formed in the plasma reaction chamber 101.

As a concrete example, the inner diameter of the vacuum chamber is 300 mm,
As a result of measuring the plasma density distribution in the radial direction of the plasma reaction chamber by probe measurement under the conditions of an etching gas pressure of 0.5 Torr, a microwave frequency of 2.45 GHz, and a magnetic flux density of 875 Gauss in the plasma reaction chamber, By adjusting the wave power, plasma with good uniformity could be formed. Then, the plasma with good uniformity allows the etching process with good uniformity to be performed on the surface of the wafer substrate 104 as the sample.

Example 2. In the above embodiment, the introduction of the microwave into the waveguide was performed from one place, but if it is performed from two places as shown in FIG. 3, a more uniform density plasma can be formed. That is, in the case of microwave feeding at one location, under the condition that the discharge gas pressure is relatively high, the coupling between the microwave propagating in the annular waveguide and the plasma becomes strong. Therefore, the coupling on the side closer to the microwave inlet becomes stronger, and the microwave cannot be propagated uniformly over the entire circumference, which makes it difficult to form a uniform plasma.
However, as shown in FIG. 3, a first microwave generation device 125 and a second microwave generation device 126 are connected to the first waveguide 121 and the second waveguide 122, respectively. When power is supplied, the microwave and plasma coupling is averaged,
A uniform plasma can be formed. In this case, a part of the E surface forming the second waveguide 122 is part of the first waveguide 121.
As a terminating plate of the second waveguide 122, a part of the E surface constituting the first waveguide 121 is used as a terminating plate of the second waveguide 122.

Embodiment 3. Further, in the above-mentioned embodiment, the microwave introduction direction is the tangential direction of the wall of the vacuum chamber 105, but it may be the direction shown in FIG. In this case, the linear waveguide 132 may be attached by cutting out an arbitrary position of the annular waveguide 131 which has been machined in advance, which simplifies the construction and manufacture of the device. 133 is a microwave end plate that smoothly guides the microwave.
It is inclined to propagate into 131.

Example 4. Further, in the above embodiment, the coupling between the microwave and the plasma is adjusted by changing the design of the thickness T of the microwave introduction window, but it may be performed by the post 142 as shown in FIG. In this case, the circular waveguide 1
41 H-plane 143 (The plane perpendicular to the electric field in the waveguide is called the H-plane)
A plurality of posts 142 are provided on the above, and the microwave matching is adjusted by the insertion degree of the posts 142. That is, the microwave impedance is adjusted by the insertion degree of the post 142.

Example 5. In addition to the fourth embodiment, as a means for adjusting the coupling between the microwave and the plasma, a metal matching plate 151 may be attached so as to surround the E surface 111 of the annular waveguide 108 as shown in FIG. In this case, the microwaves are matched with the plasma by adjusting the gap S in the range of S <T. Further, as described in the second embodiment, when the discharge gas pressure is relatively high, there is a problem that the microwave and plasma are strongly coupled and the microwave is easily absorbed in the vicinity of the microwave introduction port. If S is narrowed near the microwave introduction port to weaken the coupling with plasma and gradually widen along the transmission direction, microwaves are gradually fed to enable uniform discharge.

Example 6. In the above embodiment, the microwave introduction window is formed so as to be a part of the E surface of the waveguide, but as shown in FIG. 7, it is formed in a part of the H surface 161 of the annular waveguide 162. You may comprise so that it may become.

Embodiment 7. As shown in FIG. 1, in the semiconductor manufacturing apparatus according to the above-mentioned embodiment, the plasma reaction chamber 101 and the sample chamber are integrally formed. However, as shown in FIG. Ion extraction electrode 200 (20
0A, 200B, 200C) may be installed to extract ions from the plasma generated in the plasma reaction chamber 101 and irradiate the sample 104 in the sample chamber 201 as a shower-like ion beam. For example, of the three electrode plates of the ion extracting electrode 200, the uppermost electrode plate 200A is the plasma reaction chamber 10
The potential is the same as 1 so that a positive potential of 0 to 2 kV is applied to the ground potential. The lowermost electrode plate 200C has the ground potential and the same potential as the sample chamber 201. Middle electrode plate 200
B is applied with a negative potential of 0 to -300 V with respect to the ground potential to improve the parallelism of the shower-like ion beam,
Prevent electrons from entering from the sample chamber side. Here, the ions are the uppermost electrode plate 200A and the lowermost electrode plate 200C.
By the voltage of 0 to 2 kV applied between and, the plasma is extracted from the plasma reaction chamber 101 and accelerated to form a shower-like ion beam, which is irradiated on the sample 104.

Further, in the above embodiment, the microwave is introduced into the plasma reaction chamber 101 from the entire circumference of the vacuum chamber 105, but the present invention is not limited to this. As a result, the same effect as that of the above embodiment can be obtained. Further, although the dry etching apparatus has been described in the above embodiment, the same effect can be obtained even when applied to the plasma CVD apparatus. For example, when silane-based SiH ₄ is introduced as the CVD gas, the gas is decomposed by discharge and a silicon deposited film can be formed on the sample (wafer substrate).

[0019]

As described above, according to the first and second aspects of the present invention, the plasma reaction chamber is provided with the annular microwave introduction window and the annular waveguide along the side wall surface of the plasma reaction chamber. Since the microwave is introduced from the periphery of the chamber, it compensates for the decrease in plasma density on the side wall surface of the plasma reaction chamber and forms plasma throughout the plasma reaction chamber, enabling dry etching or film formation with good uniformity. become. Further, according to the invention of claim 3, since the microwave is fed from a plurality of locations, plasma having a uniform density distribution can be formed in the entire plasma reaction chamber. Further, according to the invention of claim 4, by providing the means for adjusting the coupling between the microwave and the plasma, there is an effect that the matching of the microwave can be performed in detail and the microwave can be efficiently introduced into the plasma reaction chamber.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a semiconductor manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a semiconductor manufacturing apparatus according to an embodiment of the present invention.

FIG. 3 is a plan sectional view showing a microwave waveguide portion of a semiconductor manufacturing apparatus according to another embodiment of the present invention.

FIG. 4 is a plan sectional view showing a microwave waveguide portion of a semiconductor manufacturing apparatus according to another embodiment of the present invention.

FIG. 5 is a side sectional view showing a microwave waveguide portion of a semiconductor manufacturing apparatus according to another embodiment of the present invention.

FIG. 6 is a side sectional view showing a microwave waveguide portion of a semiconductor manufacturing apparatus according to another embodiment of the present invention.

FIG. 7 is a side sectional view showing a microwave waveguide portion of a semiconductor manufacturing apparatus according to another embodiment of the present invention.

FIG. 8 is a side sectional view showing a semiconductor manufacturing apparatus according to another embodiment of the present invention.

FIG. 9 is a side sectional view showing a conventional semiconductor manufacturing apparatus.

[Explanation of symbols]

101 Plasma reaction chamber 102 exhaust port 103 sample table 104 samples 105 vacuum chamber 106 coils 107 gas inlet 108 Waveguide 109 microwave generator 110 microwave introduction window 111 Waveguide E side 121,122 Waveguide 123,124 End plate 125,126 Microwave generator 131 annular waveguide 132 Straight Waveguide 133 End plate 141 Waveguide 142 posts 143 Waveguide H-plane 151 Matching plate 161 Waveguide H-plane 162 Waveguide 200 ion extraction electrode 201 Sample chamber

Continued front page    (72) Inventor Akihiro Washiya             4-1-1 Mizuhara, Itami-shi Mitsubishi Electric Stock Exchange             Inside the company Kita Itami Works

Claims (4)

[Claims] 1. A plasma reaction chamber for generating plasma,
A sample stage on which a sample is placed, a gas introducing unit for introducing a gas such as reactivity, and a vacuum chamber having an exhaust unit for evacuating the chamber, and a magnetic field necessary for causing electron cyclotron resonance in the plasma reaction chamber. Magnetic field generating means for generating, a microwave introduction window provided on the peripheral wall of the plasma reaction chamber for introducing microwaves into the chamber, and an annular waveguide arranged so as to surround the microwave introduction window. A semiconductor manufacturing apparatus comprising: a microwave generator for introducing a microwave into the waveguide. 2. A plasma reaction chamber for generating plasma, gas introduction means for introducing a reactive gas or the like into the plasma reaction chamber, and a magnetic field required to cause electron cyclotron resonance in the plasma reaction chamber. A magnetic field generation means, a microwave introduction window provided on the peripheral wall of the plasma reaction chamber for introducing microwaves into the chamber, and arranged so as to surround the microwave introduction window, and are connected to the microwave generation device. And a ring-shaped waveguide and an ion extraction electrode for extracting reactive ions from the plasma generated in the plasma reaction chamber to a sample chamber in which a sample is placed. 3. The semiconductor manufacturing apparatus according to claim 1 or 2, wherein a plurality of microwave generating means are provided in a waveguide surrounding the microwave introduction window. 4. The semiconductor manufacturing apparatus according to claim 1, further comprising means for adjusting the coupling between the microwave introduced from the waveguide and the plasma generated in the plasma reaction chamber.