Liner for use in processing chamber

A container for use in a processing chamber to lessen the amount of contaminant particles found within the chamber after processing. The container fits closely within the chamber and includes ports for a gas conduit and a vacuum conduit. The container may be locked to the chamber through a locking mechanism and a recess in the container. The container may be guided into the chamber with a plurality of chamfers. The container may be used in inductively coupled plasma chambers, electron cyclotron resonance chambers, and chambers capable of receiving microwaves.

FIELD OF THE INVENTION

The present invention relates to the processing of work pieces used in semiconductor fabrication. More particularly, the present invention relates to a reusable container, or liner, for use in a work piece plasma processing chamber.

BACKGROUND OF THE INVENTION

A plasma is a collection of electrically charged and neutral particles. In a plasma, the density of negatively-charged particles (electrons and negative ions) is equal to the density of positively-charged particles (positive ions). Plasma generation may be conducted by applying power to electrodes in a chamber of a reactor. In diode or parallel plate reactors, power is applied to one electrode to generate a plasma. In triode reactors, power is typically applied to two of three electrodes to generate a plasma.

In radio frequency (RF) plasma generation, for a diode reactor, a sinusoidal signal is sent to an electrode of a pair of electrodes. Conventionally, a chuck or susceptor is the powered electrode. Examples of parallel plate reactors include the 5000MERIE from Applied Materials, Santa Clara, Calif.

A plasma source material, which typically includes one or more gases, such as, for example, argon, silane (SiH4), oxygen, TEOS, diethylsilane, and silicon tetrafluoride (SiF4), is directed to an interelectrode gap between the pair of electrodes. The amplitude of the RF signal must be sufficiently high for a breakdown of plasma source material. In this manner, electrons have sufficient energy to ionize the plasma source material and to replenish the supply of electrons to sustain a plasma. The ionization potential, the minimum energy needed to remove an electron from an atom or molecule, varies with different atoms or molecules.

In a typical triode reactor, three parallel plates or electrodes are used. The middle or intermediate electrode is conventionally located in between a top and bottom electrode, and thus two interelectrode cavities or regions are defined (one between top and middle electrode and one between middle and bottom electrode). The middle electrode typically has holes in it. Conventionally, both the top and bottom electrode are powered via RF sources, and the middle electrode is grounded. Examples of triode reactors are available from Lam Research, Fremont, Calif., and Tegal Corporation Ltd., San Diego, Calif.

Parallel plate and triode reactors generate capacitively coupled plasmas. These are conventionally “low density” plasmas (ion-electron density of less or equal to 1010ions-electrons per cm3) as compared with high-density (also known as “hi density”) plasmas which are generated by systems such as electron cyclotron resonance (ECR) and inductively coupled plasma (ICP). For ICP systems, an inductive coil (electrode) is conventionally driven at a high frequency using an RF supply. The inductive coil and RF supply provide a source power, or top power, for plasma generation. In ECR systems, a microwave power source (for example, a magnetron) is used to provide a top power. Both ICP and-ECR systems have a separate power supply known as bias power or bottom power, which may be employed for directing and accelerating ions from the plasma to a substrate assembly or other target. In either case, voltage that forms on a susceptor or chuck (also known as the direct current (DC) bias), is affected by the bottom power (RF bias); whereas, current is affected by the top power.

DESCRIPTION OF THE RELATED ART

It has been known that control of particulate contamination is imperative for cost effective, high-yielding manufacture of VLSI circuits. This control is by necessity increasing with increasingly smaller lines, feature sizes and critical dimensions being designed on such circuits. Contamination particles cause incomplete etching of work pieces such as reticules or wafers in spaces between lines, thus leading to an unwanted electrical bridge. Further, contamination particles may induce ionization or trapping centers in gate dielectrics or junctions or in reticule areas which will be used in semiconductor fabrication, leading to electrical failure of a fabricated part.

The major sources of contamination particles are personnel, equipment, and chemicals. For example, people, by shedding of skin flakes, create particles which are easily ionized and can cause defects. It is estimated that particles sized from less than 0.01 micrometers to 200 micrometers and above should be of concern during the processing of semiconductors. “Clean rooms” are typically used for semiconductor manufacture, and through filtering and other techniques, attempts are made to prevent entry of particles with sizes of 0.03 micrometers and larger. It is virtually impossible, however, to keep particles smaller than 0.03 micrometers out of a clean room.

To address the problem of semiconductor contamination, a Standard Mechanical Interface (SMIF) system was devised. The SMIF system provides a small volume of still, particle-free air, with no internal source of particles, for transporting wafers. SMIF designs are discussed in U.S. Pat. No. 5,752,796 (Muka) and U.S. Pat. No. 5,607,276 (Muka et al.).

While the SMIF system is useful for preventing particle contamination during transport of the wafers, it is wholly ineffective at preventing contamination during processing of the wafers. The SMIF containers are used during the transport of the wafers, but are removed when the wafers are placed in processing chambers for wafer processing.

Particulate contamination builds up within work piece processing chambers, such as a plasma processing chamber. This build up of contaminants must be cleansed from the processing chambers periodically. This entails considerable time and effort and requires the removal of the processing chamber from a production line. This, in turn, causes lost production time and increases costs.

There is, thus, a need in the industry for a low cost and effective method and apparatus for reducing the need to periodically clean work piece processing chambers, such as a plasma processing chamber.

SUMMARY OF THE INVENTION

The present invention provides a removable container which is inserted into a processing chamber and in which the work piece processing is carried out. The container has at least one side and a base, as well as an ingress and egress for the work piece. The container further includes one or more ports located in the side which connect with ports of the processing chamber which provide gasses or other materials used in processing. The container is made of materials allowing the container to have an effective life at least as long as the required processing, preferably allowing the container to be reused a number of times. A locking mechanism may be included to lock the container within the chamber.

The present invention also provides a system for processing a semiconductor work piece. The system includes a processing chamber and a removable container having the characteristics noted in the preceding paragraph. In one aspect of the invention, the processing chamber is a plasma processing chamber.

The present invention further provides a method of processing a semiconductor work piece in which the work piece is provided within a container, the container being removably inserted in a work piece processing chamber, with the processing being accomplished inside the container.

The invention may be used to process any work piece associated with semiconductor fabrication including, but not limited to, reticules, masks, leads, wafers, and packages.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description, the invention is described in connection with a plasma processing chamber. However, this is merely illustrative of one environment of use for the invention and the invention is not to be considered as limited to that environment. Also, the invention can be used with other work piece processing chambers. In addition, the invention is described with reference to a reticule, which is but one example of a work piece which can be processed using the invention.

Referring now to the drawings, where like numerals designate like elements, there is shown inFIG. 1a reticule processing chamber10. The processing chamber10, which is shown as being generally cylindrical in shape, is an inductively coupled plasma processing chamber and includes an inductive coil16as an electrode wrapped around a side surface14thereof. The chamber10further includes a door18and an under surface19. The door18is conventionally made to allow ingress and egress of wafers, or other semiconductor work pieces or integrated circuit packages, to be processed within the chamber10. A gas port20and a vacuum port22are provided in the door18, as shown inFIG. 2. In addition, a guiding mechanism, specifically a plurality of chamfers15,FIG. 3, are located on an inner surface of the side14of the chamber10.

As noted above, in inductively coupled plasma systems, the inductive coil, here coil16, is driven at a high frequency using a radio frequency (RF) supply27. Together, the coil and the radio frequency supply provide a source of power for the plasma generation. As shown inFIGS. 1,3, a wafer, or RF, chuck26is provided through the under surface19of the chamber10. The RF supply27, in electrical connection to the chuck26, drives the coil16at a high frequency, thereby providing the source of power for the plasma generation within the chamber10.

With further reference toFIG. 3, which is a cross-sectional view that has been elongated for clarity of description of the invention, a removable container, or liner,30is encased within the processing chamber10. The generally cylindrical container30has a base32, an upper surface34, and a side36. The upper surface34acts as a door for ingress and egress for a work piece, which is illustrated as a reticule50. It is, however, to be understood that any type of semiconductor work piece may be used with the container30, such as wafers, lead frames, or integrated circuit packages. The chuck26extends through the base32, thereby placing a top surface of the chuck26(upon which a work piece to be processes will rest) within the chamber30.

The container30may be formed of any suitable material which is able to withstand the environment within the processing chamber30for at least as long as the processing step. For example, if a conductive material is necessary, the container30may be formed of a conductive material. Alternatively, the container may be formed of a dielectric material, a partially conducting material, an insulative material, or a combination of these. Additionally, the container30may be formed of a material which would allow it to be subjected to more than one processing of a work piece, prior to being cleaned or discarded.

The upper surface34of the container30includes a gas port38and a vacuum port40. The ports38,40align with the processing chamber ports20,22when the container30is positioned within the processing chamber10.

As shown inFIGS. 1–3, a gas conduit60extends from the port20of the chamber10. It is important that the gas ports20and38closely align. Port20is in sealing and fluid communication with the port38of the container30. Further, a vacuum conduit70extends from the port22of the chamber10. It is somewhat less important for the vacuum ports22,40to closely align. While close alignment of the vacuum ports22,40may be preferable, exerting a high speed vacuum in a closed system (the chamber10) will pump the gas out of the container30even if the ports22,40are not closely aligned. As shown inFIG. 3, the port22is closely aligned to the port40of the container30. Compliant sealing members62and72are placed between the container30and processing chamber10in a space82and around the ports20,38and22,40, respectively, to provide a seal preventing fluids which pass through the ports from escaping into the space82between the container30and the processing chamber10. The conduits60,70may be pipes, hoses, or any other suitable member defining an interior space.

Alternatively, with reference toFIG. 6, the gas conduit60and vacuum conduit70may only extend into the upper surface34of the container30. A mating gas conduit60′ is fit within the port38and is adapted to mate with the conduit60. The sealing member62is placed in position to seal the junction between the conduits60and60′. A mating vacuum conduit70′ is fit within the port40and is adapted to mate with the vacuum conduit70. The sealing member72is placed in position to seal the junction between the conduits70and70′. The compliant sealing members62,72may be any suitable seal, such as an O-ring or hose clamp. Further, the sealing members62,72may not be separate sealing devices, but instead may be devices built into the hoses. For example, sealing member62may be a push-fit seal positioned at an end of the conduit60such that the conduits60and60′ may mate with and be sealed together through pushing the conduit60′ into the sealing member62.

With reference toFIGS. 7,8, the container30is shown with another aspect of the invention. To more symmetrically pump the gas and non-volatile reaction products, and thereby more efficiently clean the interior of the container30, a plurality of vacuum ports40′ are located on the upper surface34of the container30. The ports40′ spread out the vacuuming throughout the space80within the container30. Thus, a more even vacuuming of the space80may be accomplished. The vacuum conduit70should be of sufficient size to encircle all of the ports40′. As illustrated, the vacuum conduit70is not sealed to the upper surface34around the ports40′. Alternatively, the vacuum conduit70may be sealed to the upper surface34.

It is required that gas pumping, or vacuuming, speeds must be relatively high, and thus, it is necessary to provide a sufficiently large opening through which to pump the gas. Preferably, the conduit70should be between six and twenty inches in diameter. The ports40′, as shown inFIG. 7, should number between ten to twenty ports, each being between 0.02 and 0.04 inches in diameter. Contrarily, the size of a single gas conduit60need not be as large as the vacuum conduit70. Preferably, the diameter of a single gas conduit60should be in the range of about 0.4 inches. The gas may be injected into the container30through a single gas port38, as shown inFIG. 3, or alternatively, the gas may be injected through a multiple of smaller gas ports, much like the multiple ports40′ shown inFIG. 7. The multiple gas ports, typically called a gas distribution system or a gas showerhead, may be used to obtain greater uniformity of gas distribution within the container30.

The container30may be manually placed within the chamber10. The chamfers15, which have an increasing radial height in a direction from the upper surface34to the under surface36, assist in aligning the container30properly within the chamber. Robotic systems may be used to mechanically place the container30in the chamber10. Examples of suitable robotic systems include those having robot arms which are pre-aligned during maintenance and those having robot arms which are self-aligning. An important aspect of the container30is that it protects the wafer or reticule50from particles contamination caused during insertion of the container30within the chamber10, such as, for example, by striking one of the chamfers15.

Next will be described an alternative embodiment of the chamber10and the container30whereby they are supported horizontally.FIG. 9shows a horizontal processing chamber310and a container330; specifically, lying on a chamber side314and a container side336with a door318, an under surface319, an upper surface334and a base332all in a vertically directed plane. The wafer chuck326and the RF supply27are positioned under the side314of the chamber310, and inductive coils316are positioned above the chuck326on the top side of the side314. The reticule50is positioned above the chuck326when the container330is placed within the chamber310.

A locking apparatus which releasably locks the container330to the chamber310is shown inFIGS. 9,10. The locking mechanism includes a hole323provided through the chamber side314and a recess342provided in the container side336. A biased locking pin55passes through the hole323. The pin55is spring loaded and biased upwardly toward the recess342. Further, the pin55has a rounded head56to facilitate locking. Alternatively, the pin55may have a tapered or angled head56. As the container330is placed in the chamber310, the container side336slides along the chamber side314. Alternatively, this embodiment may include the chamfers15, in which case the container side336would slide along the chamfers15. When a portion of the container side336reaches the pin55, it presses the pin55downwardly against the biasing force. When the recess342reaches the locking pin55, the pressure pushing the pin55downwardly is released, allowing the pin55to move upwardly into the recess342, thereby locking the container330into place within the chamber310. The pin55may be pulled down manually, or by other means, to later unlock and release the container330from the chamber side314. The recess342can be formed of a sufficient length to ensure that the recess342meets up with the pin55.

Although the apparatus for locking the container330to the chamber310is shown as a spring-loaded locking pin55and a recess342, it is to be understood that the container330may be locked into position within the chamber310in a variety of different ways. Further, although the locking mechanism has been described in terms of theFIG. 9embodiment, it is to be understood that the locking mechanism may be included in the embodiments shown inFIGS. 3,6,8,11, and12.

Next will be described the operation of the container30(FIG. 3) within the chamber10. The reticule50is placed within the container30, the latter of which is guided into place within the chamber10by the chamfers15. The gas conduit60and the vacuum conduit70each extend through the container30and are sealed thereto with, respectively, the sealing members62,72. Alternatively, the gas and vacuum conduits60,70are mated with, respectively, the conduits60′,70′, and sealed together with the sealing members62,72. Gas is introduced to a space80within the container30through the gas conduit60. Pressure within the container30may be equalized to the pressure in the space82through a plurality of pores44in a side36of the container30. The RF supply27then drives the inductive coil16. The amplitude of the RF signal from the RF supply27needs to be sufficiently high to interact and breakdown the gas, which acts as the plasma source material. Thus, the type of gas will have a bearing upon the amplitude of the RF signal necessary from the RF supply27. The manner of creating a plasma, including the necessary gas compositions and RF voltages needed for desired processing conditions are well known in the art and are not described in detail herein.

As the plasma generated species react in the space80with the materials on the reticule50, the vacuum introduced to the container30through the vacuum conduit70pulls volatile reaction products from the container30. The build up of non-volatile reaction products will occur on the interior walls of the container30.

By utilizing the container30, less defects are deposited on the work piece during the processing. Further, the chamber10is not exposed to as many contaminant particles during the processing. Thus, the chamber10need not be wet cleaned as frequently, thus eliminating many of the re-qualifications of the chamber10. The container30itself, provided it is in a good condition to be utilized again after the processing, may be cleaned and/or refurbished and used again. Otherwise, the container30may be discarded.

FIG. 11shows another preferred embodiment of the present invention. A chamber100and a container130are shown inFIG. 11. The chamber100is generally cylindrical and includes an upper section101having a dome portion102, and the generally cylindrical container130likewise includes a dome portion132which fits within the dome portion102. The upper section101of the chamber100may be lowered onto and secured to a lower section103after the container130is placed inside the chamber100. A space180is located within the dome portion132and in the upper reaches of the rectangular portion of the container130. The space180denotes an area within the container, like space80, within which plasma products are formed through a reaction between the RF signal from the RF supply27, the inductive coil16and the gas, which is introduced through the gas conduits60. Vacuum conduits70are positioned at a lower position of the chamber130. As with previously discussed embodiments, the conduits60,70may mate with conduits60′,70′, respectively, and be sealed with sealing members62,72. The container130may be guided into the chamber100through a guiding mechanism, such as the previously described chamfers15, or any other suitable guiding mechanism. The chamber100and the container130may be supported horizontally or vertically, and a releasable locking mechanism, such as the locking pin55, may be utilized to lock the container130into place within the chamber100.

Another preferred embodiment of the present invention is shown inFIG. 12. Here, a dome-shaped processing chamber200is shown encasing a dome-shaped removable container230. The chamber200is a microwave-generated plasma chamber. Alternatively, it may be an electron cyclotron resonance chamber. The chamber200is grounded by a pair of grounding plates90.

Unlike inductively coupled plasma chambers, such as chambers10,100, the chamber200does not utilize a coil in conjunction with an RF supply to produce plasma. Instead, the microwaves216, from a microwave power source218shown schematically, provide power to generate plasma within a space280within the container230. The microwave power source218may be any suitable source, such as, for example, a magnetron. In this embodiment, the container230is preferably formed of a dielectric material. The chamber200includes a top portion201which is detachable from and securable to a bottom portion203. The top portion201is removed, allowing the container230to be placed within the chamber200.

Modifications can be made to the invention and equivalents substituted for described and illustrated structures without departing from the spirit or scope of the invention. For example, although the container30has been discussed in terms of diode processing reactors, or chambers, it is to be understood that the container30may be used with triode reactors or any other form of chamber used to process semiconductor work pieces. Further, while certain methods of plasma generation have been discussed herein, such as inductively coupled plasma, electron cyclotron resonance, and microwave, other methods of plasma generation may be utilized in the invention, such as, for example, parallel plate etchers, diodes, magnetically enhanced reactive ion etching (MERIE), and surface wave plasma. Additionally, although two ports are shown for processing a plasma, more or less ports may be used depending on the type of processing which needs to be done. Further, although conduits60,60′,70, and70′ have been described for pumping gas in and out of the container30, it is to be understood that other apparatus may be used, such as, for example, a plate having a plurality of openings positioned on a wall of the container30which is mated to a conduit. Accordingly, the scope of the present invention is not to be considered as limited by the specifics of the particular structure which have been described and illustrated, but is only limited by the scope of the appended claims.