US20030190870A1

US20030190870A1 - Cleaning ceramic surfaces

Info

Publication number: US20030190870A1
Application number: US10/115,682
Authority: US
Inventors: Hong Shih; Danny Lu; Nianci Han; Xikun Wang; Hui Chen; Hui Tang; Li Xu; Yang Zhang; Dan Wang
Original assignee: Applied Materials Inc
Current assignee: Applied Materials Inc
Priority date: 2002-04-03
Filing date: 2002-04-03
Publication date: 2003-10-09

Abstract

Method and apparatus for cleaning ceramic surfaces of parts used, for example, and without limitation, in semiconductor processing equipment. In particular, one embodiment of the present invention is a method for cleaning a ceramic part that includes steps of: (a) treating the surface using one or more first mechanical processes; (b) treating the surface using one or more chemical processes; (c) plasma conditioning the surface; and (d) treating the surface using one or more second mechanical processes.

Description

TECHNICAL FIELD OF THE INVENTION

One or more embodiments of the present invention pertain to method and apparatus for cleaning ceramic surfaces of parts used, for example, and without limitation, in semiconductor processing equipment.

BACKGROUND OF THE INVENTION

Because of the development of 300 mm semiconductor processing equipment (for example, and without limitation, etching equipment), and the shrinkage of device features to dimensions of 0.15 μm, or less, defect and particle performance of such semiconductor processing equipment becomes an important factor in achieving good production device yield. As is well known, to improve defect and particle performance (and hence yield), semiconductor processing equipment must be cleaned (prior to installation, and after use in production). At the same time, because the cost of semiconductor integrated circuit manufacturing factories (“fabs”) is going up, semiconductor processing equipment productivity is also important. However, time taken to clean equipment to improve yield tends to reduce productivity.

One way to achieve and maintain high productivity and high yield, among other things, is to increase mean wafers between clean (“MWBC”). To increase MWBC, it is well known to bead-blast ceramic surfaces of parts (such as, for example, and without limitation, a ceramic dome, a chamber lid, a focus ring, and other ceramic process kit parts) used in semiconductor processing equipment. It is believed that surface roughness improves the ability of process residues to adhere to the ceramic surfaces of the parts. It is also believed that this ability improves the defect and particle performance of the parts, and hence the defect and particle performance of the semiconductor processing equipment in which they are used. In addition to bead-blasting, wet cleaning methods have also been developed to eliminate defect and particle performance issues that arise with the use of parts having ceramic surfaces.

Although the above-described methods have been successfully applied in conjunction with parts having ceramic surfaces for use in 200 mm semiconductor processing equipment, defects and particles performance issues have arisen, among other places, in conjunction with parts having ceramic surfaces for use in 300 mm semiconductor processing equipment (and, in particular, with such parts for use in 300 mm semiconductor processing equipment used to etch small feature sizes).

In light of the above, there is a need in the art for method and apparatus for cleaning ceramic surfaces of parts used, for example, in semiconductor processing equipment.

SUMMARY OF THE INVENTION

One or more embodiments of the present invention advantageously satisfy the above-identified need in the art, and provide a method and apparatus for cleaning ceramic surfaces of parts used, for example, in semiconductor processing equipment. In particular, one embodiment of the present invention is a method for cleaning a ceramic part that comprises steps of: (a) treating the surface using one or more first mechanical processes; (b) treating the surface using one or more chemical processes; (c) plasma conditioning the surface; and (d) treating the surface using one or more second mechanical processes.

BRIEF DESCRIPTION OF THE FIGURE

FIG. 1 shows a block diagram of a cleaning method that is carried out in accordance with one embodiment of the present invention, which cleaning method is used to clean ceramic surfaces of new parts and used parts that require further bead-blasting; [0007]
FIG. 2 shows a block diagram of a cleaning method that is carried out in accordance with one embodiment of the present invention, which cleaning method is used to clean ceramic surfaces of parts having AlF[0008] ₃deposited thereon;
FIG. 3 shows a block diagram of a cleaning method that is carried out in accordance with one embodiment of the present invention, which cleaning method is used to clean ceramic surfaces of parts not having AlF[0009] ₃deposited thereon;
FIG. 4 shows a block diagram of a method that is carried out in accordance with one embodiment of the present invention, which method is used to handle parts having ceramic surfaces at a factory prior to installation; and [0010]
FIGS. [0011] 5-8 show pictorial representations of four embodiments of a plasma chamber used to provide plasma conditioning in accordance with one or more embodiments of the present invention.

DETAILED DESCRIPTION

FIG. 1 shows a block diagram of a cleaning method that is carried out in accordance with one embodiment of the present invention, which cleaning method is used to clean ceramic surfaces of new parts and used parts that require further bead-blasting. As shown at [0012] step 100 of FIG. 1, as-fired (i.e., new) parts having a ceramic surface, or used parts having a ceramic surface, are bead-blasted (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art) to provide a predetermined surface roughness. For example, in one embodiment, surface roughness may be in a range from about 20 R_ato about 120 R_a. In practice, the predetermined surface roughness may vary depending on particular processing conditions to which a part is exposed (for example, semiconductor processing conditions such as, without limitation, a type and thickness of residue deposited thereon). Appropriate ranges of values of surface roughness may be determined routinely by one of ordinary skill in the art without undue experimentation.
Next, as shown at [0013] step 110 of FIG. 1, the bead-blasted part may be rinsed, for example, using pressurized deionized water (“DI water”), to remove, for example, certain floating particles produced by the bead-blasting. The pressure used (for example, and without limitation, in one embodiment, about 50 psi) should be sufficient to enable removal of a predetermined amount of the floating particles without damaging the part. Appropriate ranges of pressure to use for such a rinse step may be determined routinely by one of ordinary skill in the art without undue experimentation. Next, as shown at step 120 of FIG. 1, the part may be dried (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art), for example, and without limitation, in one embodiment, using filtered air or N₂.
Next, as shown at [0014] step 130 of FIG. 1, in one embodiment, the ceramic surface of the part may be exposed to CO₂pellets that are propelled against the ceramic surface (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, and without limitation, in one embodiment, air may be used as a propellant. It is believed that this step removes particles by physical bombardment, and that it aids in removing polymer residues by a combination of thermal shock and physical bombardment. In particular, it is believed that the temperature of the surface of the part may be reduced (for example, to temperatures as low as −70° C.) by use of the CO₂pellets. Further, it is believed that the reduced temperature, and a thermal coefficient of expansion mismatch between the polymer residue and the ceramic surface, enables the residue to be removed by the bombardment. Appropriate ranges of values of: (a) the size of the CO₂pellets; and (b) the force at which they are propelled may be determined routinely by one of ordinary skill in the art without undue experimentation. Next, as shown at step 140 of FIG. 1, the part may be rinsed, for example, using DI water (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art).
Next, as shown at [0015] step 150 of FIG. 1, the part may be dipped in NH₄OH:H₂O₂:H₂O (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, in one embodiment, this step may: (a) use relative amounts of NH₄OH:H₂O₂:H₂O of (about 1):(about 1):(about 2) by weight; (b) be performed at a temperature below about 50° C.; and (c) last for about one (1) hour to about two (2) hours. Appropriate ranges of values of: (a) the relative amounts of NH₄OH, H₂O₂, and H₂O; (b) the temperature of the dip; and (c) the length of time of the dip may be determined routinely by one of ordinary skill in the art without undue experimentation. It is believed that NH₄OH may be useful in removing metal contaminants, and that H₂O₂may be useful in removing organic contaminants. Next, as shown at step 160 of FIG. 1, the part may be rinsed, for example, using DI water (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art).
Next, as shown at [0016] step 170 of FIG. 1, the part may be dipped in HF:HNO₃:H₂O (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, in one embodiment, this step may: (a) use relative amounts of HF:HNO₃:H₂O of (about 1):(about 1):(about 10) by weight; (b) be performed at a temperature of about 20° C.; and (c) last for about one (1) hour. Appropriate ranges of values of: (a) the relative amounts of HF, HNO₃, and H₂O; (b) the temperature of the dip; and (c) the length of time of the dip may be determined routinely by one of ordinary skill in the art without undue experimentation. It is believed that HF may be useful in removing silicon based materials (such as, for example, silicon oxide, glass, and so forth), and that HNO₃may be useful in removing metal oxides. Next, as shown at step 180 of FIG. 1, the part is rinsed, for example, in DI water (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art).
The inventors have discovered that so-called “dangling particles” produced by bead-blasting may be a source of defect and particle performance issues for parts having ceramic surfaces, especially when such parts are used in semiconductor processing equipment used to fabricate integrated circuits on 300 mm wafers. In addition, the inventors have discovered that these “dangling particles” may be removed by utilizing: (a) a chemically enhanced clean step; and/or (b) a plasma conditioning step that provides physical bombardment and/or a chemical reaction in a gas phase environment (for example, and without limitation, by utilizing a high density plasma). A chemically enhanced clean step in accordance with one embodiment of the present invention proceeds as follows. As shown at [0017] step 190 of FIG. 1, the part may be dipped in H₂SO₄:H₂O₂(in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, in one embodiment, this step may: (a) use relative amounts of H₂SO₄:H₂O₂of (about 1):(about 1) by weight; (b) be performed at a temperature of about 140° C.; and (c) last for about one (1) to about two (2) hours. Appropriate ranges of values of: (a) the relative amounts of H₂SO₄, and H₂O₂; (b) the temperature of the dip; and (c) the length of time of the dip may be determined routinely by one of ordinary skill in the art without undue experimentation. Next, as shown at step 200 of FIG. 1, the part is rinsed, for example, in DI water (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). Then, as shown in FIG. 1, processing continues at step 230.
A plasma conditioning step in accordance with one embodiment of the present invention proceeds as follows. As shown at [0018] step 210 of FIG. 1, the part is baked to remove water remaining from step 180 of FIG. 1 (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, in one embodiment, this step may: (a) entail baking the part in an oven; (b) be performed at a temperature of about 110° C.; and (c) last for about one (1) hour. Appropriate ranges of values of: (a) the temperature of the bake; and (b) the length of time of the bake may be determined routinely by one of ordinary skill in the art without undue experimentation. Next, as shown at step 220 of FIG. 1, the part is plasma conditioned in a plasma chamber (embodiments of which are described in detail below). In accordance with one embodiment of the present invention, the plasma chamber utilizes an RF source of electromagnetic energy to generate a plasma therein, for example, an inductively coupled plasma—typically a high density plasma. Further, as set forth below, such a plasma chamber can operate at a wide range of pressures, for example, and without limitation, pressures such as, for example, from about 100 mT to below about 50 mT. In addition, in accordance with one embodiment of the present invention, a plasma is formed using: (a) an inert gas such as, for example, and without limitation, argon (Ar) to provide a physical bombardment mechanism for cleaning; and/or (b) one or more reactive gases such as, for example, and without limitation, chlorine (Cl₂) or BCl₃to provide a chemically reactive mechanism for cleaning. The particular type of gas to provide the chemically reactive mechanism may be chosen depending on the type of ceramic surface to be cleaned, and the processes applications in which it is used. In addition, as will be explained below, it is advantageous for the plasma chamber to include adapters to enable plasma conditioning of parts used in both 200 mm and 300 mm processing chambers. In accordance with this embodiment, plasma conditioning step 220 can last for about thirty (30) minutes to about several hours, depending on the process applications and materials under treatment. Lastly, appropriate ranges of values of: (a) plasma chamber pressure; (b) gases used to form the plasma; (c) the length of time of plasma conditioning; (d) the energy and frequency of the source of electromagnetic energy used to create the plasma; and (e) plasma chamber temperature may be determined routinely by one of ordinary skill in the art without undue experimentation.
In accordance with another embodiment of the present invention, the plasma chamber utilizes an RF source of electromagnetic energy to generate a plasma therein, for example, a capacitively coupled plasma. Further, as set forth below, such a plasma chamber can operate at a wide range of pressures, for example, and without limitation, pressures such as, for example, from about 1 T to about 50 T. In addition, in accordance with one embodiment of the present invention, a plasma is formed using: (a) an inert gas such as, for example, and without limitation, argon (Ar) to provide a physical bombardment mechanism for cleaning; and/or (b) one or more reactive gases such as, for example, and without limitation, chlorine (Cl[0019] ₂) or BCl₃to provide a chemically reactive mechanism for cleaning. The particular type of gas to provide the chemically reactive mechanism may be chosen depending on the type of ceramic surface to be cleaned, and the processes applications in which it is used. In accordance with this embodiment, plasma conditioning step 220 can last for about thirty (30) minutes to about several hours, depending on the process applications and materials under treatment. Lastly, appropriate ranges of values of: (a) plasma chamber pressure; (b) gases used to form the plasma; (c) the length of time of plasma conditioning; (d) the energy and frequency of the source of electromagnetic energy used to create the plasma; and (e) plasma chamber temperature may be determined routinely by one of ordinary skill in the art without undue experimentation.
In accordance with yet another embodiment of the present invention, the plasma chamber utilizes a remote plasma generator to generate a plasma which then flows into the plasma chamber. Further, as set forth below, such a plasma chamber can operate at a wide range of pressures. In addition, in accordance with one embodiment of the present invention, a plasma is formed using one or more reactive gases such as, for example, and without limitation, chlorine (Cl[0020] ₂) or BCl₃to provide a chemically reactive mechanism for cleaning. The particular type of gas to provide the chemically reactive mechanism may be chosen depending on the type of ceramic surface to be cleaned, and the processes applications in which it is used. In accordance with this embodiment, plasma conditioning step 220 can last for about thirty (30) minutes to about several hours, depending on the process applications and materials under treatment. Lastly, appropriate ranges of values of: (a) plasma chamber pressure; (b) gases used to form the plasma; (c) the length of time of plasma conditioning; (d) the number distribution of various plasma species; and (e) plasma chamber temperature may be determined routinely by one of ordinary skill in the art without undue experimentation.
Next, as shown at [0021] step 230 of FIG. 1, the part may be exposed to a stream of, for example, filtered air or N₂(in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). This step may be used to remove excess water if the precursor step was step 200, and this step may be used to remove accumulated particles if the precursor step was step 220. Next, as shown at step 240 of FIG. 1, the part is transferred to a cleanroom, for example, and without limitation, a Class 100 cleanroom, for any further processing. Then, as further shown at step 240 of FIG. 1, small particles may be removed. For example, the part may be exposed to CO₂snow (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). Appropriate ranges of values of: (a) snow temperature; and (b) the force at which the snow is propelled may be determined routinely by one of ordinary skill in the art without undue experimentation. Us Next, as shown at step 250 of FIG. 1, the part may be rinsed, for example, in DI water (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). Then, the part may be exposed to a stream of, for example, filtered air or N₂to remove excess water. Next, as shown at step 260 of FIG. 1, a surface roughness measurement may be made in accordance with any one of a number of methods that are well known to those of ordinary skill in the art. If the surface does not have a predetermined degree of roughness (see above), then the part may be returned to step 100 of FIG. 1 for further bead-blasting.
Next, as shown at [0022] step 270 of FIG. 1, the part may be cleaned by high purity DI water ultrasonic cleaning (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, in one embodiment, this step may: (a) utilize DI water whose purity is such that it has a resistivity of about 12 MΩ or higher; (b) be performed at a temperature of about 50° C.; and (c) last for about two (2) hours. Appropriate ranges of values of: (a) the purity of the DI water; (b) the temperature of the cleaning step; and (c) the length of time of the cleaning step may be determined routinely by one of ordinary skill in the art without undue experimentation. In addition, in one embodiment, an endpoint for this cleaning step may be determined by using a liquid particle counter (“LPC”) measurement (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). The endpoint is signaled when the number of particles measured by LPC falls below a predetermined amount. Appropriate ranges of values of: (a) the temperature of the cleaning step; and (b) the length of time of the cleaning step may be determined routinely by one of ordinary skill in the art without undue experimentation.
Next, as shown at [0023] step 280 of FIG. 1, the part is rinsed, for example, in high purity DI water (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, in one embodiment, this step may utilize DI water whose purity is such that it has a resistivity of about 12 MΩ or higher. Then, the part may be exposed to a stream of, for example, N₂(in accordance with any one of a number of methods that are well known to those of ordinary skill in the art) to remove excess water. Appropriate ranges of values of the purity of the DI water may be determined routinely by one of ordinary skill in the art without undue experimentation. Next, as shown at step 290 of FIG. 1, the part is baked to remove water remaining after step 280 (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, in one embodiment, this step may: (a) entail baking the part in an oven; (b) be performed at a temperature of about 150° C.; and (c) last for about two (1) hours. Appropriate ranges of values of the temperature of the bake, and the length of time of the bake may be determined routinely by one of ordinary skill in the art without undue experimentation.
Next, as shown at [0024] step 300 of FIG. 1, a surface particle measurement is made after the part has cooled down to about room temperature (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art is made). For example, the measurement may be made using a QIII particle counter. For example, in one embodiment, this measurement detects particles of size about 0.3 μm or larger. If the number of particles is higher than a predetermined amount, then the part may be returned to step 180 of FIG. 1. Next, as shown at step 310 of FIG. 1, the part is exposed to a stream of filtered, pure, dry air or N₂(in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, in one embodiment, the purity of the air or N₂are such that any particles have a size of about <0.1 μm or smaller. Appropriate ranges of values of the purity of the air or N₂may be determined routinely by one of ordinary skill in the art without undue experimentation. Lastly, as shown at step 320 of FIG. 1, the part is vacuum sealed and packaged (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art).
As one can readily appreciate from the description above, steps [0025] 100, 110, 120, 130, 140, 160, 180, 200, 210, 230, 240, 250, 270, 280, 290, and 310 of FIG. 1 are mechanical processes, and steps 150, 170, and 190 of FIG. 1 are chemical processes. In further embodiments of the present invention, one or more of the above-described chemical steps may further include, or be replaced by, other chemical steps such as one or more of an H₂O₂dip (it is believed that this process step may be useful in removing organic contaminants); an HCl:H₂O₂dip (it is believed that this process step may be useful in removing metal contaminants), an HF dip (it is believed that this process step may be useful in removing silicon based materials—such as, for example, silicon oxide, glass, and so forth); an HNO₃:H₂O₂dip (it is believed that this process step may be useful in removing metal oxides and organic contaminants); an isopropyl alcohol (IPA) dip; and an acetone dip.
The above-described cleaning process may be used to process any number of types of parts having ceramic surfaces, including, without limitation, parts having surfaces comprised of alumina, YAG, Si, SiC, AlN, Si[0026] ₃N₄, Spinel, ZrO₂; and parts having chemical vapor deposited ceramic coatings, plasma spray ceramic coatings, and anodized ceramic coatings.
The process described above in conjunction with FIG. 1 may also be utilized to clean “used” parts having ceramic surfaces which do not require bead-blasting by omitting [0027] step 100 of FIG. 1. Here, the term “used” parts refers to parts that, for example, have been used to process wafers in a semiconductor processing equipment, by omitting step 100.
FIG. 2 shows a block diagram of a cleaning method that is carried out in accordance with one embodiment of the present invention, which cleaning method is used to clean ceramic surfaces of parts having AlF[0028] ₃deposited thereon. As one can readily appreciate from this, many of the steps of this cleaning process are the same as steps of the cleaning process shown in FIG. 1 and described above (and hence have the same numeric designations). As such, the following will only describe steps that are different from those shown in FIG. 1. As shown at step 400 of FIG. 2, the part may be dipped in H₂O₂:H₂O (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, in one embodiment, this step may: (a) use a concentration of H₂O₂:H₂O of about 30 wt % H₂O₂; (b) be performed at a temperature below about 50° C.; and (c) last for about one (1) hour. Appropriate ranges of values of: (a) the concentration of H₂O₂; (b) the temperature of the dip; and (c) the length of time of the dip may be determined routinely by one of ordinary skill in the art without undue experimentation. Next, as shown at step 410 of FIG. 2, the part may be rinsed, for example, in DI water (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). Then, the part may be exposed to a stream of air to remove excess water (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art).
Next, as shown at [0029] step 420 of FIG. 2, the part may be cleaned (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art) using, for example, acetone, isopropyl alcohol (IPA), and a brush, for example, a Scotch Brite™ brush (a brush that is sold by 3M Corporation) at about room temperature. Appropriate ranges of values of: (a) the temperature; and (b) the concentrations of the acetone and IPA may be determined routinely by one of ordinary skill in the art without undue experimentation.
Lastly, as shown at [0030] step 430 of FIG. 2, the part may be dipped (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art) in an NMD-3 solution (NMD-3 is a mixture of tetramethyl ammonium hydroxide [N(CH₃)₄OH] and water that is available from Tokyo Ohka Kogyo Co., Ltd. through, for example, Ohka America, Inc. of Milpitas, Calif., that is believed to remove AlF_x). For example, in one embodiment, this step may: (a) use an about 2.38 wt % NMD-3 solution; (b) be performed at a temperature of about room temperature or higher (for example, and without limitation, at a temperature of about 50° C.; and (c) last for about two (2) hours. Appropriate ranges of values of: (a) the concentration of NMD-3; (b) the temperature of the dip; and (c) the length of time of the dip may be determined routinely by one of ordinary skill in the art without undue experimentation. Alternatively, to remove AlF_x, step 430 of FIG. 2 may be replaced by a bake step (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, this step may use an oven bake above a temperature where AlF₃is volatile. Since AlF₃is volatile above about 550° C. to about 575° C., in one embodiment, one may use a bake temperature of about 800° C.
As one can readily appreciate from the description above, steps [0031] 110, 120, 410, 140, 160, 200, 230, 240, 250, 270, 280, 290, and 310 of FIG. 2 are mechanical processes, and steps 400, 420, 150, and 430 of FIG. 2 are chemical processes. In further embodiments of the present invention, the mechanical steps may include use of a CO₂ice pellet cleaning and/or a CO₂snow cleaning. In still further embodiments of the present invention, one or more of the above-described chemical steps may further include, or be replaced by, other chemical steps such as one or more of an HF:HNO₃:H₂O dip (it is believed that this process step may be useful in removing silicon based materials, and metal oxides); an H₂SO₄:H₂O₂dip; an HCl:H₂O₂dip (it is believed that this process step may be useful in removing metal contaminants), an HF dip (it is believed that this process step may be useful in removing silicon based materials—such as, for example, silicon oxide, glass, and so forth); and an HNO₃:H₂O₂dip (it is believed that this process step may be useful in removing metal oxides and organic contaminants).
FIG. 3 shows a block diagram of a cleaning method that is carried out in accordance with one embodiment of the present invention, which cleaning method is used to clean ceramic surfaces of parts not having AlF[0032] ₃deposited thereon. As one can readily appreciate from this, many of the steps of this cleaning process are the same as steps of the cleaning process shown in FIG. 1 and described above (and hence have the same numeric designations). As such, the following will only describe steps that are different from those shown in FIG. 1. As shown at step 500 of FIG. 3, the part may be dipped in H₂O₂:H₂O (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, in one embodiment, this step may: (a) use a concentration of H₂O₂:H₂O of about 30 wt % H₂O₂; (b) be performed at a temperature below about 50° C.; and (c) last for about one (1) hour. Appropriate ranges of values of: (a) the concentration of H₂O₂; (b) the temperature of the dip; and (c) the length of time of the dip may be determined routinely by one of ordinary skill in the art without undue experimentation. Next, as shown at step 510 of FIG. 3, the part may be rinsed, for example, in DI water (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). Then, the part may be exposed to a stream of air to remove excess water (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). Next, as shown at step 520 of FIG. 3, the part may be cleaned (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art) using, for example, acetone, IPA, and a brush, for example, a Scotch Brite™ brush at about room temperature. Appropriate ranges of values of: (a) the temperature; and (b) the concentrations of the acetone and IPA may be determined routinely by one of ordinary skill in the art without undue experimentation.
As one can readily appreciate from the description above, steps [0033] 110, 120, 510, 140, 160, 230, 240, 250, 270, 280, 290, and 310 of FIG. 3 are mechanical processes, and steps 500, 520, and 150 of FIG. 3 are chemical processes. In further embodiments of the present invention, the mechanical steps may include use of a CO₂ice pellet cleaning and/or a CO₂snow cleaning. In still further embodiments of the present invention, one or more of the above-described chemical steps may further include, or be replaced by, other chemical steps such as one or more of an HF:HNO₃:H₂O dip (it is believed that this process step may be useful in removing silicon based materials, and metal oxides); an H₂SO₄:H₂O₂dip; an HCl:H₂O₂dip (it is believed that this process step may be useful in removing metal contaminants), an HF dip (it is believed that this process step may be useful in removing silicon based materials—such as, for example, silicon oxide, glass, and so forth); and an HNO₃:H₂O₂dip (it is believed that this process step may be useful in removing metal oxides and organic contaminants).
FIG. 4 shows a block diagram of a method that is carried out in accordance with one embodiment of the present invention, which method is used to handle parts having ceramic surfaces at a factory prior to installation. As shown at [0034] step 600 of FIG. 4, a package of parts having a ceramic surface is opened in a cleanroom. Next, as shown at step 610 of FIG. 4, the part may be rinsed, for example, in DI water (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). Next, as shown at step 620 of FIG. 4, the part may be cleaned by a high purity DI water ultrasonic cleaning process (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, in one embodiment, this step may: (a) utilize DI water whose purity is such that it has a resistivity of about 12 MΩ or higher; (b) be performed at a temperature of about 50° C.; and (c) last for about two (2) hours. Appropriate ranges of values of: (a) the purity of the DI water; (b) the temperature of the cleaning step; and (c) the length of time of the cleaning step may be determined routinely by one of ordinary skill in the art without undue experimentation. Next, as shown at step 630 of FIG. 4, the part may be rinsed, for example, in high purity DI water (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). Then, the part may be exposed to a stream of, for example, N₂(in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). This may be used to blow off excess water. Next, as shown at step 640 of FIG. 4, the part may be baked to remove water remaining after step 630 of FIG. 4 (in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, in one embodiment, this step may: (a) entail baking the part in an oven; (b) be performed at a temperature of about 150° C.; and (c) last for about two (1) hours. Appropriate ranges of values of: (a) the temperature of the bake; and (b) the length of time of the bake may be determined routinely by one of ordinary skill in the art without undue experimentation. Next, as shown at step 650 of FIG. 4, after the part has cooled down, it may be exposed to a stream of, for example, filtered, high purity N₂(in accordance with any one of a number of methods that are well known to those of ordinary skill in the art). For example, in one embodiment, the purity of the N₂is such that any particles have a size of about or <0.1 μm. This step may be used to remove accumulated particles. An appropriate range of values of the purity of the N₂may be determined routinely by one of ordinary skill in the art without undue experimentation. Next, as shown at step 660, the part is either vacuum sealed or transferred directly to the semiconductor processing equipment in which it is to be installed. Lastly, as shown at step 670, in one embodiment, the part may be exposed to a stream of, for example, N₂, and it may be wiped with IPA.
FIGS. 5 and 6 show pictorial representations of two embodiments of a plasma chamber used to provide plasma conditioning in accordance with one or more embodiments of the present invention. In particular, FIG. 5 shows [0035] chamber 700 used to plasma condition “shaped” ceramic dome 710. As shown in FIG. 5, plasma chamber 700 comprises cathode base structure 720, chamber body 730, pedestal 740, O-ring 750, adapter 760, O-ring 770, RF coil 780, O-ring 790, coil power supply 791, cathode power supply 792, and controller 795. Cathode base structure 720 provides a cathode in a manner that is well known to those of ordinary skill in the art, and supports parts having ceramic surfaces mounted on pedestal 740 thereon. O-ring 790 seals the interior of chamber 700, and such a seal may be fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art. O-rings 750 and 770 seal the interior of chamber 700, and are disposed between chamber body 730 and adapter 760, and between adapter 760 and ceramic dome 710, respectively. Adapter 760 is shaped to be used with both a dome from 200 mm semiconductor processing equipment and a dome from 300 mm semiconductor processing equipment. As such, for use with a dome from 200 mm equipment, adapter 760 will extend into the interior of chamber 700, since chamber 700 will ordinarily be sized for use with a dome from 300 mm equipment.
[0036] RF coil 780 is fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art to produce a substantially inductively coupled plasma, typically, a high density plasma, in chamber 700. Advantageously, the use of a high density plasma better enables control between amounts of physical bombardment and chemical reaction in the plasma conditioning process. Coil power supply 791 is fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art to cause RF coil 780 to generate a plasma in the interior of chamber 700. Appropriate ranges of frequency and power may be determined routinely by one or ordinary skill in the art without undue experimentation. Cathode power supply 792 is fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art to produce a bias voltage on pedestal 740. Coil power supply 791 and cathode power supply 792 operate in response to signals from controller 795. As is well known, various amounts of RF energy and cathode bias, as well as the particular gases and pressures thereof, and temperature within chamber 7000, control the amount of physical bombardment and chemical reaction occurring in chamber 700. Gas inlets (not shown) enable gas to flow into chamber 700. Controller 795 is also connected to gas input controllers (not shown, but fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art), and to a chamber exhaust mechanism (not shown, but fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art) to control the pressure inside chamber 700. In addition, controller 795 is also connected to a heating mechanism disposed, for example, in pedestal 740 (not shown, but fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art), to help control (along with a measure of the physical bombardment) the temperature inside chamber 700.
FIG. 6 shows [0037] chamber 800 used to plasma condition flat ceramic dome 810. As shown in FIG. 6, plasma chamber 800 is similar in all respects (other than dome 710) to chamber 700. In particular, chamber 800 comprises cathode base structure 820, chamber body 830, pedestal 840, O-ring 850, adapter 860, O-ring 870, RF coil 880, O-ring 890, coil power supply 891, cathode power supply 892, and controller 895. It should be appreciated by those of ordinary skill in the art that similarly number parts in FIGS. 5 and 6 provide similar functionality as that described above for chamber 700.
It should also be appreciated by those of ordinary skill in the art that [0038] chambers 700 and 800 shown in FIGS. 5 and 6, respectively, may also be used to plasma condition parts other than domes. Such parts may be placed on pedestals 740 and 840, respectively, or they may be disposed on appliances that may be fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art.
FIG. 7 shows [0039] chamber 1000 used to plasma condition parts disposed therein. As shown in FIG. 7, plasma chamber 1000 comprises cathode base structure 1020, chamber body 1030, pedestal 1040, O-ring 1090, top-plate power supply 1091, cathode power supply 1092, and controller 1095. Cathode base structure 1020 provides a cathode in a manner that is well known to those of ordinary skill in the art, and supports parts having ceramic surfaces mounted on pedestal 1040 therein. O-ring 1090 seals the interior of chamber 1000, and such a seal may be fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art.
Top-[0040] plate 1080 is fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art to produce a substantially capacitively coupled plasma in chamber 1000. For example, as shown in FIG. 7, gas flows from line 1057 into chamber 1000 through gas distribution box 1065. The gas may enter chamber 1000 through channels in top-plate 1080 (for example, top-plate 1080 may comprise a showerhead), or through gas inlets. Appropriate gas distribution mechanisms can be fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art. Top-plate power supply 1091 is fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art to cause top-plate 1080 to generate a plasma in the interior of chamber 1000. Appropriate ranges of frequency and power may be determined routinely by one or ordinary skill in the art without undue experimentation. Cathode power supply 1092 is fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art to produce a bias voltage on pedestal 1040. Appropriate ranges of frequency and power may be determined routinely by one or ordinary skill in the art without undue experimentation. Top-plate power supply 1091 and cathode power supply 1092 operate in response to signals from controller 1095. As is well known, various amounts of RF power and cathode bias, as well as particular gases and pressures thereof, and temperature within chamber 1000, control the amount of physical bombardment and chemical reaction occurring in chamber 1000. Controller 1095 is also connected to gas input controllers (not shown, but fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art), and to a chamber exhaust mechanism (not shown, but fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art) to control the pressure inside chamber 1000. In addition, controller 1095 is also connected to a heating mechanism disposed, for example, in pedestal 1040 (not shown, but fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art), to help control (along with a measure of the physical bombardment) the temperature inside chamber 1000. Lastly, parts to be conditioned may be placed on pedestal 1040, or they may be disposed on appliances that may be fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art.
FIG. 8 shows chamber [0041] 1100 used to plasma condition parts disposed therein. As shown in FIG. 8, plasma chamber 1100 comprises pedestal base structure 1120, chamber body 1130, pedestal 1140, O-ring 1190, remote plasma generator 1157, heater power supply 1177, and controller 1195. Pedestal base structure 1120 supports parts having ceramic surfaces mounted on pedestal 1140 thereon. O-ring 1190 seals the interior of chamber 1100, and such a seal may be fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art.
As shown in FIG. 8, [0042] remote plasma generator 1157 generates a plasma in accordance with any one of a number of methods that are well known to those of ordinary skill in the art. For example, in accordance with one embodiment of remote plasma generator 1157, a gas flows through a tube that is exposed to microwaves output from a microwave generator in accordance with any one of a number of methods that are well known to those of ordinary skill in the art. A plasma is formed which flows through gas line 1159 into chamber 1100 through gas distribution box 1153. The plasma may enter chamber 1000 through channels in top-plate 1180 (for example, top-plate 1180 may comprise a showerhead), or through gas inlets. Appropriate gas distribution mechanisms can be fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art. An appropriate distance between remote plasma generator 1157 and gas distribution box 1153 may be determined routinely by one of ordinary skill in the art without undue experimentation to enable a predetermined number distribution of various plasma species to be present inside chamber 1000. In addition, appropriate ranges of microwave frequency and power, and gas pressure in remote plasma generator 1157 may be determined routinely by one or ordinary skill in the art without undue experimentation.
In accordance with an alternative embodiment of [0043] remote plasma generator 1157, a gas flows into an entrance channel in a toroidal tube. A coil is wound about at least a portion of the tube, and the coil is energized by RF energy in accordance with any one of a number of methods that are well known to those of ordinary skill in the art to generate a plasma in the toroidal tube. The plasma gas flows out of an exit channel in the toroidal tube, through gas line 1159, and into chamber 1100 through gas distribution box 1153. Appropriate ranges of RF frequency and power, and gas pressure in remote plasma generator 1157 may be determined routinely by one or ordinary skill in the art without undue experimentation. As is well known, the number distribution of various plasma species, as well as the particular gases used and the pressures thereof, as well as temperature within chamber 1100, control the amount of chemical reaction occurring in chamber 1100.
[0044] Controller 1195 is also connected to gas input controllers for remote plasma generator 1157 (not shown, but fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art), and to a chamber exhaust mechanism (not shown, but fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art) to control the pressure inside chamber 1100. In addition, controller 1195 is also connected to heating power supply 1187 disposed, for example, in pedestal 1140 (not shown, but fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art), to help control the temperature inside chamber 1100. Lastly, parts to be conditioned may be placed on pedestal 1140, or they may be disposed on appliances that may be fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art without undue experimentation.
It should be understood by those of ordinary skill in the art that all the power supplies described above include apparatus to provide impedance matching in accordance with any one of a number of methods that are well known to those of ordinary skill in the art. [0045]
Those skilled in the art will recognize that the foregoing description has been presented for the sake of illustration and description only. As such, it is not intended to be exhaustive or to limit the embodiments of the present invention to the precise form disclosed. For example, further embodiments of the present invention exist wherein plasma conditioning is performed by use of plasma sprays or plasma guns that are fabricated in accordance with any one of a number of methods that are well known to those of ordinary skill in the art. In addition, although one or more embodiments of the present invention have been described in the context of parts used in semiconductor processing equipment, embodiments of the present invention are not limited to parts used in such equipment. Further, the term semiconductor processing equipment relates to equipment which processes semiconductor wafers or glass substrates, to equipment used to inspect wafers and/or substrates, and to equipment used to manufacture masks used to manufacture integrated circuits and/or optical components. [0046]

Claims

What is claimed is:

1. A method for cleaning a part having a ceramic surface which comprises steps of:

treating the surface using one or more first mechanical processes;

treating the surface using one or more chemical processes;

plasma conditioning the surface; and

treating the surface using one or more second mechanical processes.

2. The method of claim 1 wherein the step of treating the surface using one or more first mechanical processes includes bead-blasting.

3. The method of claim 1 wherein the step of plasma conditioning comprises inductively coupling energy to a plasma in a chamber and exposing the surface to the plasma in the chamber.

4. The method of claim 3 which further includes forming the plasma utilizing precursors that include an inert gas.

5. The method of claim 4 wherein the inert gas comprises Ar.

6. The method of claim 4 wherein the precursors further include a reactive chemical.

7. The method of claim 6 wherein the reactive chemical comprises Cl₂.

8. The method of claim 6 wherein the reactive chemical comprises BCl₃.

9. The method of claim 1 wherein the step of plasma conditioning comprises capacitively coupling energy to a plasma in a chamber and exposing the surface to the plasma in the chamber.

10. The method of claim 9 wherein the step of exposing comprises disposing the surface in a plasma chamber, and the step of capacitively coupling includes forming the plasma utilizing precursors that include an inert gas.

11. The method of claim 10 wherein the inert gas comprises Ar.

12. The method of claim 10 wherein the precursors further include a reactive chemical.

13. The method of claim 1 wherein the step of plasma conditioning comprises generating a plasma, flowing the plasma into a chamber, and exposing the surface to the plasma in the chamber.

14. The method of claim 13 wherein the step of generating includes exposing a gas to microwaves.

15. The method of claim 13 wherein the step of generating includes exposing a gas to RF energy.

16. The method of claim 1 wherein the step of treating the surface using one or more first mechanical processes comprises steps of:

rinsing the surface using pressurized deionized water; and

propelling CO₂pellets against the surface.

17. The method of claim 1 wherein the step of treating the surface using one or more chemical processes comprises steps of:

dipping the part in NH₄OH:H₂O₂:H₂O; and

dipping the part in HF:HNO₃:H₂O.

18. The method of claim 1 wherein the step of treating the surface using one or more second mechanical processes comprises steps of:

propelling CO₂snow against the surface; and

ultrasonically cleaning the surface using deionized water.

19. A method for cleaning a part having a ceramic surface which comprises steps of:

treating the surface using one or more first mechanical processes;

treating the surface using one or more chemical processes;

exposing the surface to H₂SO₄:H₂O₂; and

treating the surface using one or more second mechanical processes.

20. The method of claim 19 wherein the step of treating the surface using one or more first mechanical processes includes bead-blasting.

21. A method for cleaning a part having a ceramic surface which comprises steps of:

treating the surface using one or more first mechanical processes;

treating the surface using one or more chemical processes;

exposing the surface to NMD-3; and

treating the surface using one or more second mechanical processes.