Microwave plasma processing apparatus

In accordance with example embodiments, a plasma processing apparatus includes a chamber configured to perform a plasma process, an upper plate on the chamber, an antenna under the upper plate and the antenna is configured to generate plasma in the chamber, an upper insulator between the upper plate and the antenna and the upper insulator covers a top of the antenna, a lower insulator covering a bottom of the antenna, an antenna support ring configured to fix the antenna to the upper plate, and a metal gasket adhered to the antenna support ring.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority under 35 U.S.C. §119 to the benefit of Korean Patent Application Nos. 2010-0063961 and 2011-0057331 filed on Jul. 2, 2010 and Jun. 14, 2011 in the Korean Intellectual Property Office, the entire disclosure of each of which is incorporated herein by reference.

BACKGROUND

Example embodiments relate to a plasma processing apparatus.

2. Description of the Related Art

A plasma processing apparatus, for example a plasma processing apparatus that generates plasma using a microwave, may be used to form an insulating film on a semiconductor wafer and/or etch a film on a semiconductor wafer.

In some plasma processing apparatuses, electric current may be transmitted to an antenna in order to generate a plasma. An antenna may be provided between an upper plate and a lower ring and the lower ring may be pressed by a bolt. The antenna may be a conductor. During operation, when electric current is transmitted to an antenna, the antenna may generate heat due to the resistance of the conductor.

Due to thermal expansion effects, a circular antenna may expand in a radial direction when heated.

However, when a bolt passes through the antenna, the bolt may limit the antenna from being lengthened in the radial direction. Instead, the antenna can swell upward.

The top of the antenna may be supported by the clamping force of the bolt. The thermal expansion of the antenna may exert a force on the antenna.

Over time, heating may deform the antenna. Deformation of the antenna may have negative effects on the plasma process in which the antenna is used and may cause a slot in the antenna to arch.

In order to limit the antenna from heating, a thickness of an upper insulator may be reduced and the temperature of cooling water may be lowered. As a result, plasma generation efficiency may deteriorate and condensation may occur near the upper plate. An additional apparatus to prevent condensation may be required.

Thermal expansion may also oxidize the surface of the antenna. In order to limit oxidation on the antenna surface, the antenna may be plated with gold. However, the gold-plated layer can be detached.

SUMMARY

Example embodiments relate to a plasma processing apparatus, a main part for a plasma processing apparatus, and/or an antenna for a plasma processing apparatus.

Example embodiments relate to a plasma processing apparatus including a chamber configured to perform a plasma process, an upper plate on the chamber, an antenna under the upper plate and the antenna is configured to generate a plasma in the chamber, an upper insulator between the upper plate and the antenna and the upper insulator covers a top of the antenna, a lower insulator covering a bottom of the antenna, an antenna support ring configured to fix the antenna to the upper plate, and a metal gasket adhered to the antenna support ring.

The antenna may be a flat plate antenna.

The antenna may include a plurality of slots including a variety of shapes, the plurality of slots defined by at least one inner surface of the antenna.

The antenna may include a circumferential surface, and a plurality of grooves defined by the circumferential surface.

The antenna support ring may include a plurality of protrusions along a circumferential surface of the antenna support ring.

The plasma processing apparatus may include a metal gasket that is configured to push the antenna up to maintain contact between the antenna and the upper plate.

The metal gasket may be configured to maintain electrical contact between the antenna and the antenna support ring.

The chamber of the plasma processing apparatus may include a susceptor that is configured to support a semiconductor wafer. The susceptor may be connected to at least one of a heater to heat the semiconductor wafer and an electrode configured to apply RF bias.

Example embodiments relate to a main part for a plasma processing apparatus including a chamber, an antenna support ring on the chamber, an antenna on the antenna support ring, an insulator covering the antenna, and an upper plate on the insulator. The antenna is configured to generate a plasma in the chamber. The antenna support ring may be configured to fix the upper plate to the antenna.

The antenna may include a flat plate shape and a circumferential surface. The antenna may further include a plurality of grooves defined by the circumferential surface.

The antenna support ring may include a plurality of protrusions along a circumference of the antenna support ring. The plurality of protrusions may include a size that is smaller than a size of the plurality of grooves of the antenna. The plurality of protrusions each define a coupling hole. The main part may further include a plurality of coupling bolts inserted through the coupling holes and the plurality of protrusions, each coupling bolt coupled to the protrusions and configured to fix the antenna to the upper plate.

Each protrusion may be within each groove. A space may be provided between each protrusion in each groove, based on the size of the protrusions being smaller than the size of the grooves.

The antenna may include a plurality of slots including a variety of shapes, the plurality of slots defined by at least one inner surface of the antenna.

The main part of the plasma apparatus may further include at least one metal gasket adhered to the antenna support ring. The metal gasket may be configured to maintain electrical contact between the antenna and the antenna support ring.

Example embodiments relate to an antenna for a plasma processing apparatus, including a flat plate shape and a plurality of grooves defined by a circumferential surface of the antenna. The plurality of grooves may be distributed along a circumference of the antenna.

The antenna may further include a plurality of slots including a variety of shapes. The plurality of slots may be defined by at least one inner surface of the antenna.

The plurality of grooves may include a u-shape.

DETAILED DESCRIPTION

FIG. 1is a sectional view schematically illustrating a microwave plasma processing apparatus1according to example embodiments.

As shown inFIGS. 1 to 4, a microwave plasma processing apparatus1includes: a chamber10in which plasma processing is performed; an upper plate20provided on the top of the chamber10; an antenna30provided under the upper plate20to generate plasma in the chamber10; an upper insulator40provided between the upper plate20and the antenna30to cover the top of the antenna30; a lower insulator50provided under the antenna30to cover the bottom of the antenna30; an antenna support ring60provided under the antenna30to fix the antenna30to the upper plate20; and a gasket70adhered to the antenna support ring60. The gasket70may be a metal, but example embodiments are not limited thereto. Further, whileFIGS. 1 to 4discuss a microwave plasma processing apparatus, example embodiments may also relate to plasma processing apparatuses that generate frequencies at frequencies outside the microwave range. Plasma processing apparatuses according to example embodiments may be used to deposit thin films, such as insulating films, and/or to remove thin films by an etching and/or ashing process, but example embodiments are not limited thereto.

As shown inFIG. 1, the microwave plasma processing apparatus1is provided with a chamber10in which plasma processing is performed.

In the chamber10, electric current is transmitted along the surface of the antenna30and a gas which passes through the lower insulator50provided under the antenna30and is supplied thereto is converted into plasma to form an insulating film on a semiconductor wafer W (the wafer W is not shown inFIG. 1, but refer toFIGS. 5and/or6).

As shown inFIG. 1, the upper plate20is provided on the chamber10and may serve as a cooling plate.

The upper plate20may be provided with a channel (not shown inFIG. 1, but refer toFIG. 4for an illustration of the channel C) through which cooling water flows.

The antenna30may be made of a conductor. The antenna30may be provided under the upper plate20and the antenna30may generate plasma in the chamber10.

The antenna30may be a flat plate antenna to produce plasma at a uniform (or substantially uniform) density over a large area, but example embodiments are not limited thereto and the antenna may be other shapes.

As shown inFIG. 2, the lower insulator50, the antenna support ring60, the antenna30, and the upper insulator40may have a circular and/or flat plate shapes, but example embodiments are not limited thereto. The lower insulator50, the antenna support ring60, the antenna30, and the upper insulator40may be sequentially stacked. The antenna30includes a plurality of slots31which may have a variety of shapes, the slots31defined by inner surfaces of the antenna30.

Microwaves are irradiated into the chamber10through the slots31provided in the antenna30.

In order to irradiate microwaves into the chamber10, electric current is transmitted to the antenna30, causing the antenna30to be heated.

The antenna30may heat up due to the resistance of the conductor when power is applied to the antenna30.

The antenna30can expand due to thermal expansion effects when the antenna30is heated. In particular, the antenna30including a circular shape may be thermally expanded and thus lengthened in a radial direction as represented by an arrow, when heated to several hundred degrees, as shown inFIG. 3.

When heated, the antenna30is not lengthened in the radial direction due to the clamped bolt and instead swells upward, since it passes through the bolt and thus comes in contact with the upper plate20.

For this reason, the antenna30is deformed, for example, distorted, over time, having an effect on the process, and in serious cases, causing the slots31of the antenna30to be arced.

In order to reduce thermal expansion of the antenna30in the radial direction caused by heating, the antenna30may be provided with a plurality of long grooves33along the circumferential surface thereof, as shown inFIG. 2.

Referring toFIGS. 2 and 4, a protrusion61formed along the circumferential surface of an antenna support ring60may be inserted into and coupled to the long groove33formed along the circumferential surface of the antenna30.

The protrusion61formed along the circumferential surface of the antenna support ring60is provided with a coupling hole63.

A bolt B, as shown inFIG. 4, may be inserted through the coupling hole63formed on the antenna support ring60and through the long groove33to fix the antenna30to the upper plate20.

As shown inFIG. 4, the long groove33formed along the circumferential surface of the antenna30is larger than the protrusion61formed along the circumferential surface of the antenna support ring60, thus providing a space between the long groove33and the protrusion61.

The space enables the antenna30to expand in a radial direction, when heated, and minimizes the effect of the bolt on the antenna30expanding in a radial direction.

Accordingly, in a case where the antenna30undergoes thermal expansion in a radial direction, the antenna30may expand more freely in a radial direction without being deformed. Further, the impact on the process from the antenna30being distorted may be reduced, and the antenna30may maintain contact with the upper plate20.

As shown inFIGS. 1,2, and4, upper and lower insulators40and50are provided over and below the antenna30, respectively.

The upper insulator40is provided between the upper plate20and the antenna30. The upper insulator40covers the top of the antenna30, and the upper insulator40insulates the antenna30from coming into contact with the upper plate20. Cooling water may flow in the upper plate20, and the cooling water can minimize the antenna30from being heated.

The lower insulator50is provided under the antenna30and covers the bottom of the antenna30. The lower insulator50insulates the antenna30. The lower insulator50may have a dome structure that can withstand vacuum, but example embodiments are not limited thereto.

As shown inFIGS. 1 to 4, the antenna support ring60is provided under the antenna30, to fix the antenna30to the upper plate20.

As mentioned above, the antenna support ring60is provided with the protrusions61along the circumferential surface thereof, and the protrusions61are provided with coupling holes63, through which bolts B may be coupled to the protrusion61.

The protrusion61may be formed along the circumferential surface of the antenna support ring60and inserted into and coupled to a long groove33of the antenna30. A long groove33of the antenna may be formed along a circumferential surface of the antenna30. A bolt B may be coupled through the long groove33and the coupling hole63provided in the protrusion61to fix the antenna30to the upper plate20.

As shown inFIGS. 2 and 3, a plurality of metal gaskets70serving as springs may be adhered to the antenna support ring60.

The metal gaskets70adhered to the top of the antenna support ring60push the antenna30up, like a spring, to maintain contact between the antenna30and the upper plate20by a desired (or alternatively predetermined) force.

When the antenna30heats up when power is applied, the antenna30can slide, but a friction force of the metal gasket70, serving as a spring, and is naturally expanded in the radial direction and maintains contact between the antenna30and the upper plate20.

Similar to that the space is formed between the long groove33formed along the circumferential surface of the antenna30and the protrusion61formed along the circumferential surface of the antenna support ring60to allow the antenna30to be lengthened in the radial direction by thermal expansion, the surrounding structure and the outer diameter of the antenna30may be spaced by a desired (or alternatively a predetermined) distance or more.

In addition, the metal gasket70maintains electrical contact between the antenna30and the antenna support ring60.

Referring toFIG. 5, a microwave plasma processing apparatus1may be configured to receive a semiconductor wafer W (or substrate). The wafer W may be loaded in the chamber10to be plasma processed. The wafer may be fixed on the susceptor80. The chamber10includes a gauge11(or alternatively a pressure sensor such as a manometer and/or pressure transducer, and the like) to measure an internal pressure of the chamber10when the semiconductor wafer W is plasma-processed and/or when the chamber10does not include a wafer W loaded therein. The microwave plasma processing apparatus1may include at least one gas nozzle13through which a gas is supplied to the chamber10. WhileFIG. 5discusses a microwave plasma processing apparatus, example embodiments are not limited thereto and may include a plasma processing apparatus that generates plasmas at other frequencies besides the microwave frequency range.

A support91to support the susceptor80, and a fixing unit90, on which the support91is fixed, are arranged under the susceptor80.

A pressure control valve93may be arranged under the fixing unit90, to automatically control and/or maintain the pressure in the chamber10. The pressure in the chamber10may be measured by the gauge11provided in the chamber10. A turbo pump95may be arranged under the pressure control valve93. The turbo pump may95remove gas from the chamber10, for example gas supplied supplied through the gas nozzle13provided in the chamber10.

The susceptor80may be provided with a heater81to heat the semiconductor wafer W in order to improve properties of the semiconductor wafer W during the plasma processing of the semiconductor wafer W, and an electrode83to apply radio frequency (RF) bias to the semiconductor wafer W.

AlthoughFIG. 5illustrates a configuration in which both the heater81and the electrode83are provided, example embodiments are not limited thereto. Either the heater81or electrode83may be provided separately and/or omitted without limitation.

The heater81and the electrode83provided in the susceptor80may be connected through an inner conductor85to an outer alternating current supply module87or RF module89.

The heater81receives alternating current from the alternating current supply module87connected through the conductor85and heats the semiconductor wafer W. The alternating current supply module87to supply alternating current to the heater81may be divided into two sections to separately control two regions of the susceptor80.

The electrode83receives an RF bias from the RF module89connected through the conductor85and applies the RF bias to the semiconductor wafer W. The RF module89is configured to apply an RF bias to the electrode83. The RF module includes an RF generator (not shown), an RF cable (not shown) and an RF matching network (not shown) to transfer RF power.

When the electrode83applies RF bias to the semiconductor wafer W, RF noise or leaked current may be transferred to the heater81due to an inner structure of the susceptor80. In order to prevent this phenemenon, the RF module89may include an RF filter (not shown).

FIG. 6illustrates another a microwave plasma processing apparatus1′, according to example embodiments, in which a gas present in a chamber of a microwave plasma processing apparatus1′ may be discharged.

As shown inFIG. 6, the microwave plasma processing apparatus1′ is designed such that an internal pressure thereof is controlled using a throttle valve97connected to a dry pump99through the discharge pipe P and at the same time, the inner gas of the chamber10is discharged through a discharge pipe P.

As apparent from the foregoing, in accordance with example embodiments, the antenna30can more freely expand through the long groove formed33along the circumferential surface of the antenna30and the protrusion61formed along the circumferential surface of the antenna support ring60.

In addition, the antenna can maintain electrical contact through the metal gasket70when the antenna30is thermally expanded.

In addition, based on the aforementioned configuration, close contact between the antenna30, and upper40and lower insulators50can be realized, more stable plasma processing can be maintained and a stable plasma state can be obtained.

Although example embodiments have been particularly shown and described, it will be appreciated by those skilled in the art that variations in form and detail may be made therein without departing from the spirit and scope of the claims and their equivalents.