KR101216701B1 - Apparatus for Dry Etching - Google Patents

Abstract

Dry etching apparatus is provided. The dry etching device includes a chamber, a chuck installed in the chamber, a focus ring surrounding the chuck, and a displacement device for changing the relative position of the focus ring with respect to the extended surface of the surface of the chuck.

Focus ring, plasma, dry etching device

Description

Dry etching apparatus {Apparatus for Dry Etching}

The present invention relates to a dry etching apparatus, and more particularly, to a dry etching apparatus including a focus ring.

Dry etching is mainly used to form fine patterns of highly integrated semiconductor devices. The dry etching apparatus includes a chamber, an electrostatic chuck installed in the chamber, and electrodes provided above and below the electrostatic chuck. The dry etching process may be performed by converting a source gas introduced into the chamber into a plasma by high frequency power applied between the electrodes and etching the wafer seated on the electrostatic chuck using the plasma. Specifically, radicals or ions constituting the plasma react with the material film on the wafer physically and chemically to etch the material film.

On the other hand, in the dry etching apparatus, since the plasma is generated by the electrodes provided above and below the electrostatic chuck, the plasma can be easily controlled up to the installation portion of the electrode, but the plasma peripheral control of the outer periphery of the electrostatic chuck is relatively difficult. For example, the amount of plasma generated in the outer periphery is relatively small, whereby the etch rate of the edge of the wafer may be somewhat lower than in the central region. As a result, it is difficult to achieve a uniform etch rate over the entire surface of the wafer.

In order to improve the etching uniformity of the wafer, a method of mounting a focus ring around the electrostatic chuck is adopted. Since the amount of plasma generation and its pattern change depending on the shape, height, and the like of the focus ring, fine adjustment of the plasma generates a more uniform plasma on the surface of the wafer so that the reaction ions uniformly reach the upper surface of the wafer.

However, since there are structural limitations in the fine adjustment of the shape and height of the focus ring, it is very difficult to reach the target precise plasma generation pattern control.

Further, when performing a dry etching process, not only the wafer and / or the structure thereon, but also the focus ring are etched together. When the focus ring is etched, its shape and height change, thereby changing the plasma generation pattern that was originally set. This makes it difficult to achieve the process goal of uniform etch rate across the wafer surface. To prevent this, the focus ring can be replaced after performing a predetermined number of etchings, but frequent replacement of the focus ring delays the processing time and increases the process cost.

The present invention has been conceived based on these points, and the problem to be solved by the present invention is to provide a dry etching apparatus capable of more precise plasma generation pattern control.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

Dry etching apparatus according to an embodiment of the present invention for solving the above problems the relative position of the focus ring with respect to the chamber, the chuck installed in the chamber, the focus ring surrounding the chuck, and the extended surface of the surface of the chuck. Includes a displacement device to change.

The displacement device may be a device for adjusting the position of the focus ring in the vertical direction.

The focus ring may be connected to a DC power source.

Furthermore, the focus ring may include an electrode inside or on the bottom surface.

In addition, the focus ring may be formed of a semiconductor.

The details of other embodiments are included in the detailed description and drawings.

According to embodiments of the present invention has at least the following effects.

That is, in the dry etching apparatus according to some embodiments of the present invention, since the relative position of the focus ring with respect to the extended surface of the chuck surface is easily controlled by the displacement device, there is a structural limitation in the shape design of the focus ring, or Even when partially etched, the shape and height of the substantial focus ring can be reset. Therefore, since a uniform etching rate can be achieved without replacing the focus ring, the process cost can be reduced and the process efficiency can be improved.

In addition, in the dry etching apparatus according to another exemplary embodiment of the present invention, DC power may be applied to the focus ring, thereby finely adjusting the plasma generation pattern of the wafer edge region. Therefore, more precise and wide etching rate control is possible.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

Advantages and features of the present invention, and methods of achieving the same will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

References to elements or layers "on" other elements or layers include all instances where another layer or other element is directly over or in the middle of another element. On the other hand, a device being referred to as "directly on" refers to not intervening another device or layer in the middle. Like reference numerals refer to like elements throughout. "And / or" include each and any combination of one or more of the mentioned items.

The spatially relative terms " below ", " beneath ", " lower ", " above ", " upper " It may be used to easily describe the correlation of a device or components with other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when flipping a device shown in the figure, a device described as "below" or "beneath" of another device may be placed "above" of another device. Thus, the exemplary term "below" can include both downward and upward directions. The device can also be oriented in other directions, so that spatially relative terms can be interpreted according to orientation.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention.

1 is a cross-sectional view of a dry etching apparatus according to an embodiment of the present invention.

Referring to FIG. 1, a dry etching apparatus 1 according to an embodiment of the present invention may include a chamber 110, a susceptor 120, an electrostatic chuck 130, a focus ring 140, a displacement device, and a thermal medium flow path. 152, a gas flow path 154, a feed line 156, an exhaust ring 160, a shower head 170, and a magnetic field forming mechanism 180.

The chamber 110 is a space where a dry etching process is performed. When a dry etching apparatus is used for semiconductor wafer processing as in the example of FIG. 1, the chamber 110 may be cylindrical. However, when the dry etching apparatus is a substrate processing apparatus for a display device such as an LCD, the chamber 110 may have a rectangular parallelepiped or other shape.

The chamber 110 may be made of aluminum on the surface of which anodization film (aluminate) is formed, and the inside of the chamber 110 may be configured to be airtightly closed. In addition, the chamber 110 is connected to a ground potential, and a susceptor 120 serving as a lower electrode is provided inside the chamber 110. The susceptor 120 may be, for example, aluminum in which an anodized film (alumite) is formed.

An electrostatic chuck (ESC) 130 is provided on the wafer W mounting surface of the susceptor 120. The electrostatic chuck 130 may mainly use ceramic as a main material, and a DC power supply 132 is connected to the electrode for the electrostatic chuck of the electrostatic chuck 130.

Also, on the susceptor 120 and / or the electrostatic chuck 130, a focus ring 140 formed in an annular shape to surround the wafer W is provided. The focus ring is provided with a displacement device to adjust the position of the focus ring. In some embodiments, the focus ring is connected to a direct current power source. A more detailed description of the focus ring is described below.

Inside the susceptor 120, a thermal medium flow path 152 for circulating the insulating fluid for temperature control is installed. The susceptor 120 is controlled to a predetermined temperature by circulating the insulating fluid controlled to a predetermined temperature in the thermal medium flow path 152.

A gas flow path 154 for supplying a gas for temperature control such as helium gas to the back surface of the semiconductor wafer W is provided. Specifically, the gas for temperature control is supplied between the susceptor 120 and the back surface of the wafer W to promote heat exchange therebetween. Therefore, the precision of the semiconductor element manufactured by the wafer W can be made high, and it can control to predetermined temperature efficiently.

In addition, a feed line 156 for supplying high frequency power is connected to the center of the susceptor 120. The power supply line 156 is connected to a high frequency power source (RF power supply) 159 via a matching unit 158. The high frequency power supply 159 is supplied with a high frequency power of a predetermined frequency.

In addition, an exhaust ring 160 formed in an annular shape and having a plurality of exhaust holes is provided outside the susceptor 120. A vacuum pump of the exhaust system 164 connected to the exhaust port 162 via the exhaust ring 160 is configured to perform vacuum exhaust of the processing space in the reaction chamber 110.

On the other hand, the shower head 170 is provided in the ceiling wall portion of the reaction chamber 110 above the susceptor 120 to face the susceptor 120 in parallel. In particular, the shower head 170 is grounded so that the susceptor 120 and the shower head 170 function as a pair of electrodes (upper electrode and lower electrode).

The shower head 170 is provided with a plurality of gas discharge holes 171 at the lower surface thereof, has a gas introduction portion 172 at an upper portion thereof, and a gas diffusion cavity 174 therein. A gas supply pipe 175 is connected to the gas inlet 172, and a gas supply system 176 is connected to the other end of the gas supply pipe 175. The gas supply system 176 is composed of a Mass Flow Controller (MFC) 177 for controlling a gas flow rate, and a reactive gas supply source 178 for supplying a reactive gas, for example.

When power is applied to the susceptor 120 and the shower head 170, the source gas flows into the chamber 110 through the gas inlet 172, and the source gas flows into the susceptor 120 and the shower head 170. Can be excited with plasma in between. The source gas may be a fluorine-containing etching gas and may be a CF 4 gas. Radicals and ions constituting the plasma may etch the wafer W deposited on the electrostatic chuck 130. Reaction byproducts remaining after the etching process may be discharged to the outside of the chamber 110 through the exhaust system 164.

On the other hand, an annular magnetic field forming mechanism (ring magnet) 180 is disposed around the outer side of the reaction chamber 110 to form a magnetic field in the processing space between the susceptor 120 and the shower head 170. have. The magnetic field forming mechanism 180 is rotatable in its entirety by the rotation mechanism 182 at a predetermined rotational speed around the reaction chamber 110.

2 is a schematic view illustrating a focus ring 140 and a displacement device 190 of a dry etching apparatus according to an embodiment of the present invention. Referring to FIG. 2, the focus ring 140 is formed to surround the electrostatic chuck 130 to define a mounting margin of the wafer W. Referring to FIG. The inner diameter shape of the focus ring 140 is set to a shape suitable for improving the uniformity of the plasma.

In more detail, some radicals or ions constituting the plasma also impinge on the focus ring 140, of which some radicals and ions may be refracted toward the wafer W side. Thus, the amount of radicals and ions reaching the wafer W edge may increase. The amount of plasma that is concentrated toward the wafer W varies according to the inner diameter shape and the height of the focus ring 140. With precise control of this, the uniform etching rate can be realized by compensating for the amount of radicals and ions that reach the edge region of the wafer W where a relatively small amount of plasma is generated.

The displacement device 190 changes the position of the focus ring 140 relative to the extended surface of the surface of the electrostatic chuck 130. In some embodiments, the displacement device 190 is a device for adjusting the position of the focus ring 140 in the vertical direction. Even if the electrostatic chuck 130 is fixed by the displacement device 190, the relative position of the focus ring 140 with respect to the extended surface of the surface of the electrostatic chuck 130 is adjusted.

When the focus ring 140 is displaced in the vertical direction by the displacement device 190, substantially the same height as the height of the focus ring 140 may be achieved. Therefore, even if the focus ring 140 of a specific height is applied, the same effect as that of applying the focus ring 140 of a desired height can be obtained.

In addition, while performing a plurality of dry etching, the focus ring 140 may also be etched together so that the height and shape of the focus ring 140 may be deformed. In this case, the focus ring 140 may be substantially changed by the displacement device 190. ) Height can be adjusted. Therefore, the amount of radicals and ions reaching the edge of the wafer W can be finely adjusted without replacing the focus ring 140. That is, the replacement cycle of the focus ring 140 may be long. Therefore, while improving the etch rate uniformity, it is possible to reduce the process cost and improve the process efficiency.

In some other embodiments of the invention, the displacement device 190 may displace the focus ring 140 in the horizontal direction. Depending on the shape of the inner diameter of the focus ring 140, the horizontal displacement may bring about the effect of the height adjustment of the focus ring 140. In some embodiments, the displacement device 190 may displace the focus ring 140 in both the horizontal and vertical directions. In another alternative embodiment, the displacement device 190 may tilt the focus ring 140 at an angle.

The applicable displacement device 190 may include a lift module including a motor, a laminate structure, a fine screw adjustment structure, an elastic structure such as a spring, and the like, but is not limited thereto, and various displacement devices known in the art may be used. Can be applied.

3 is a schematic view for explaining a dry etching apparatus according to another embodiment of the present invention. Referring to FIG. 3, the focus ring 140 according to the present embodiment is connected to a DC power source 192, and a DC power source 192 is applied thereto. When a DC power source 192 is applied to the focus ring 140, an electric field may be generated between the focus ring 140 and the shower head 170. If the intensity of the DC power supply 192 is applied, the amount of plasma generated according to this may be adjusted. Therefore, since the plasma amount of the relatively small wafer W edge region can be amplified, it is easy to uniformly control the overall amount of lyric and ions reached throughout the wafer W surface. Therefore, there is a limitation of the structural shape of the focus ring 140, so that it is difficult to finely adjust only the shape, or even when the shape and / or the height is changed by the etching of the focus ring 140, the DC power applied to the focus ring 140 ( By controlling the intensity of 192, the etch rate uniformity may be realized. In addition to applying the DC power source 192 to the focus ring 140, it will be understood that more precise and wide etch rate control is possible by controlling the above-described displacement device 190 together.

In order to apply the DC power source 192 to the focus ring 140, a control electrode 194 may be installed. However, in this case, the control electrode 194 is preferably installed on the bottom surface of the focus ring 140 rather than being installed on the upper surface of the focus ring 140.

In some other embodiments, the focus ring 140 is made of a semiconductor instead of including a separate regulating electrode 194, which may itself be directly applied with a direct current power source 190.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may be embodied in other specific forms without changing the technical spirit or essential features of the present invention. I can understand that. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

1 is a cross-sectional view of a dry etching apparatus according to an embodiment of the present invention.

2 is a schematic diagram illustrating a focus ring and a displacement device of a dry etching apparatus according to an exemplary embodiment of the present invention.

3 is a schematic view for explaining a dry etching apparatus according to another embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

1: dry etching device

110: chamber

140: focus ring

190: displacement device

192: DC power

194: control electrode

Claims (5)

chamber; A chuck installed in the chamber; A focus ring surrounding the chuck; And A displacement device for changing the relative position of the focus ring with respect to the extended surface of the surface of the chuck, And the displacement device displaces the focus ring in the horizontal and vertical directions simultaneously, or tilts the lens at a predetermined angle to adjust the position of the focus ring. delete The method according to claim 1, And the focus ring is connected to a direct current power source. The method of claim 3, The focus ring is a dry etching apparatus is provided with a control electrode on the lower surface. The method of claim 3, The focus ring is a dry etching device consisting of a semiconductor.

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