WO2003057642A1

WO2003057642A1 - Processes for cleaning semiconductor equipment parts

Info

Publication number: WO2003057642A1
Application number: PCT/US2002/041427
Authority: WO
Inventors: Henry Peebles
Original assignee: Advanced Technology Materials Inc
Current assignee: Advanced Technology Materials Inc
Priority date: 2001-12-31
Filing date: 2002-12-27
Publication date: 2003-07-17
Anticipated expiration: 2004-06-30
Also published as: AU2002361866A1

Abstract

The present invention relates to a cleaning process for removing epoxy resin from ceramic substrates, the process includes: a) contacting the ceramic substrate with heated N-methylpyrrolidone for a sufficient time to swell and mechanically weaken the bonding of the epoxy resin to the ceramic substrate; b) wiping the weakened epoxy resin from the ceramic substrate; c) rinsing the ceramic substrate with at least one organic solvent; and d) vacuum baking the ceramic substrate at a sufficient temperature and time to remove solvent residues from the ceramic substrate. Another process provides for cleaning a contaminant-bearing quartz process chamber, in which the process includes the steps of: (a) contacting the quartz process chamber in a tank containing an aqueous acid solution; (b) removing the quartz process chamber from the acid tank; (c) rinsing the quartz process chamber in a rinse tank containing deionized water (d) draining and refilling the rinse tank at least one to facilitate effective fluid exchange in the interior of the quartz process chamber; (e) repeating steps a-d until residue is substantially removed from process chamber; and (f) drying the quartz process chamber with ionized clean dry air.

Description

PROCESSES FOR CLEANING SEMICONDUCTOR EQUIPMENT PARTS

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The priority of United States Provisional Application No. 60/346,025 filed December 31, 2001 is hereby expressly claimed.

BACKGROUND OF THE INVENTION

Field of the Invention

[0002] The present invention relates generally to processes for cleaning parts, and more particularly, to cleaning processes for cleaning semiconductor equipment parts without corroding or destroying the surfaces of the equipment parts.

Description of the Related Art

[0003] In the field of semiconductor manufacturing, the repetitive use of process equipment creates a corresponding need for cleaning surfaces of the equipment, to renew them for renewal of processing capability.

[0004] Virtually all equipment parts used in a semiconductor-processing tool require maintenance and cleaning to ensure proper performance of the tool. Because, the individual parts are fabricated from multiple types of materials, the composition, physical properties, and chemistry of each substrate must be considered in the cleaning and regenerating process. Hardness, porosity, thermal coefficient of expansion, conductivity, melting point, specific heat, the effect of embrittlement, chemical permeability and corrosion resistance must also be considered. Thus, each cleaning process should be tailor-made for the specific part, exposed surfaces and nature of contamination. [0005] In order to properly design a cleaning system and process, the composition of contamination on the material surface must be determined. Understanding that any particles or contamination left on the equipment part will affect the operation of the processing tool, the cleaning process must consider whether the contamination includes organic and/or inorganic particles. Further, the cleaning process must be sufficient to remove contamination without changing the chemical structure of the metallic or ceramic surface thereby avoiding any weakening of the structural integrity of the equipment part when reintroduced into the processing tool.

[0006] Multiple issues must be addressed in assessing a cleaning process, including, the ultimate cleanliness requirement of the surface, the compatibility of the cleaning process with the material/coating of the part, the length of cleaning process, the ease of installing or operating in situ cleaning versus removal of the part, and whether the cleaning process will affect subsequent operability of the cleaned part.

[0007] Thus, a principal object of the present invention is to provide effective methods of cleaning contaminants from equipment surfaces in the fabrication of integrated circuits without corroding or destroying the parts and surfaces of the equipment.

SUMMARY OF THE INVENTION

[0008] The present invention in one aspect relates to a cleaning process for a contaminant- bearing quartz process chamber, in which the cleaning process includes the steps of (a) contacting the quartz process chamber with an aqueous acid solution; (b) removing the quartz process chamber from the acid tank; (c) rinsing the quartz process chamber in a rinse tank containing deionized water; (d) draining and refilling the rinse tank at least once to facilitate effective fluid exchange in the interior of the quartz process chamber; (e) repeating steps a-d until residue is substantially removed from the quartz process chamber; (f) drying the quartz process chamber with ionized clean dry air; and (g) packaging and sealing the quartz process chamber in a poly bag.

[0009] Another aspect of the invention relates to a process for cleaning a quartz part, such as a quartz process chamber, comprising the steps of: (a) submerging and soaking the quartz part in an aqueous acid solution containing HF and HNO₃;

(b) rinsing the quartz part in a rinse tank containing deionized water;

(c) draining and refilling the rinse tank at least once to facilitate effective fluid exchange in any interior areas of the quartz part; and

(d) drying the quartz part with ionized clean dry air.

[0010] Preferably, the quartz part is resubmersed in the rinse tank after the rinse tank has been completely drained and rinsed with deionized water and during which the rinse tank is isolated from ambient surroundings to reduce contamination of the water with air.

[0011] A still further aspect of the invention relates to a process for cleaning a ceramic material equipment part, such as MOER rings, the process comprising the steps of:

(a) air baking the ceramic material part for at a sufficient temperature and time to modify contaminant residue;

(b) contacting the ceramic material part with a cleaning solution comprising an oxidizing agent and a fluoride ion containing compound; and

(c) rinsing the ceramic material part at least once with deionized water; and

(d) vacuum baking the ceramic material part for a sufficient time to remove substantially all absorbed cleaning solution.

[0012] The contaminant of the ceramic material may include aluminum fluoride, silicon fluoride, tungsten fluoride, titanium fluoride and or the corresponding oxides and oxyfluorides.

[0013] In another aspect, the invention relates to a process of removing epoxy resin from ceramic substrates, the process comprising: a) contacting the ceramic substrate with heated N-methylpyrrolidone for a sufficient time to swell and weaken the bonding of the epoxy resin to the ceramic substrate;

b) wiping the weakened epoxy resin from the ceramic substrate;

c) rinsing the ceramic substrate with at least one organic solvent; and

d) vacuum baking the ceramic substrate at a sufficient temperature and time to remove solvent residues from the ceramic substrate.

[0014] In yet another aspect, the invention relates to a method of increasing the operating life of a semiconductor processing tool, in which the semiconductor manufacturing tool comprises a quartz substrate part that is contaminated with a contaminant species deriving from a semiconductor process, the method comprising:

(a) submerging the quartz substrate part in a tank containing an aqueous acid solution; (b) removing the quartz substrate part from the acid tank; (c) submerging the quartz substrate part in a rinse tank containing deionized water (d) draining and refilling the rinse tank at least once to facilitate effective fluid exchange in any interior area of the quartz substrate part; e) repeating steps a-d until residue is substantially removed from the quartz substrate; and f) drying the quartz substrate with ionized clean dry air.

[0015] Another aspect of the invention relates to a method of determining amenability of a ceramic surface of a semiconductor equipment part to soaking with a solvent treatment to remove epoxy resin, wherein the soaking treatment includes exposure of the ceramic surface to heated N-methylpyrrolidone (NMP), said method comprising: contacting the ceramic surface with heated NMP of at least the same strength as that involved in said soaking treatment followed by vacuum baking of the part, and determining whether ceramic surface releases NMP during the vacuum baking step, and contraindicating the surface as amenable to the soaking method of hot NMP treatment if evidence of absorption of NMP at depths greater than 60 A remains after vacuum baking. [0016] Other aspects, features and advantages of the invention will be more fully apparent from the ensuing disclosure and appended claims.

BRIEF DESCRIPTION OF THE DPAWINGS

[0017] FIGURES IA and IB show damage to a quartz substrate caused by a higher acid concentration relative to the concentration of the present invention.

FIGURES 2A shows surface treatment with acid solutions of the present invention and 2B show damage to a quartz substrate caused by a higher acid concentration relative to the concentration of the present invention.

FIGURES 3A and 3B show damage to a quartz substrate caused by extended soaking in the acid bath.

FIGURE 4A illustrates the epoxy residue observable as a brown strip down the middle of the substrate.

FIGURE 4B shows the pad of Figure 4A after the cleaning process using NMP.

FIGURE 5 is a graph illustrating transmission spectra of a treated window and three untreated windows at normal incidence using a double beam spectrometer.

FIGURE 6 is a plot of ion current as a function of sputter depth for mass 14 (nitrogen) for an as received coupon, NMP treated coupon, vacuum baked coupon, and vacuum baked control coupon.

FIGURE 7 is a plot of ion current as a function of sputter depth for mass 13 (carbon) for an as received coupon, NMP treated coupon, vacuum baked coupon, and vacuum baked control coupon. DETAILED DESCRIPTION OF THE INVENTION. AND PREFERRED EMBODIMENTS

THEREOF

[0018] The disclosure of United States Provisional Application No. No. 60/346,025 filed December 31, 2001 is hereby incorporated herein by reference in its entirety.

One aspect of the invention provides effective treatment of contaminant-bearing quartz equipment parts, such as processing chambers, to remove such contaminants, e.g., process- related contaminants such as reagent residues, and degradation and reaction byproducts of reagents used in the active processing carried out in the process system comprising the quartz chamber. The quartz chambers are specifically used for epitaxial deposition of silicon and germanium on semiconductor wafers. Thus, primary process contamination on the chambers includes partially fluorinated hydrocarbons, elemental silicon, elemental germanium, and the common air formed oxides of silicon and germanium. The contaminants may further comprise free iron, oxide scale, rust, grease, oil, carbonaceous and other residual chemical films, soil, particles, metal chips, and dirt.

[0019] In one aspect, the cleaning procedure comprises acid soaking and multiple rinsing. The acid solution comprises at least one acid and may be employed in any suitable concentration that removes contaminants without causing damage to the quartz substrate. For the most preferred acid soaking solutions, the acid species is nitric acid with a concentration preferably in a range of from about 2% to about 5% by weight, based on the total weight of the aqueous acid solution, and more preferably from about 2% to about 3% by weight. The acid solution may further comprises hydrofluoric acid in a concentration from about 2% to about 5% by weight, and more preferably, from about 2% to about 3%. In a specific application of the cleaning process, the acid solution comprises about 2% of nitric acid and 2% HF.

[0020] It has been found that although the acid concentrations are low the acid soaking solution is sufficient to remove contamination from the quartz substrate without damaging the quartz surface. Preferably, the soaking period is from about 45 minutes to about 90 minutes, and more preferably, about 45 minutes to 60 minutes. Acid solutions of the prior art that include higher acid concentrations can cause damage to the quartz substrate as shown in Figures IB and 2B. Further, even at the lower concentrations recited in the present invention, the soaking time should be limited to less than 90 minutes thereby preventing any damage to the quartz substrate, as shown in Figure 3B, which is the results of soaking in the acid solution for the extended period of three hours.

[0021] The present invention includes one acid soak tank and two deionized (DI) water rinse tanks. Preferably, the tanks are fabricated from polypropylene and have sufficient dimensions to completely hold the quartz chamber and allowing for submerging thereof. More preferably, the dimensions of the tanks are about 32" in length, 22" in width, and of sufficient height to provide at least a 12" depth of any liquid therein.

[0022] The cleaning procedure for the quartz processing chambers, such as a quartz epitaxial deposition process chamber contaminated with elemental silicon and germanium, may include any or all of the following steps:

1) Initially the tanks are cleaned by wiping or rinsing the internal surfaces with 6% HNO₃. After the acid treatment, each tank is thoroughly rinsed with DI water at least time. Preferably at least 5 gallons of DI water is used for each rinse.

2) Filling the acid tank with 2% HF and 2% HNO₃ and the rinse tanks with DI water.

3) Soaking the quartz lenticular chamber in the 2% HF and 2% HNO acid tank at a temperature ranging from about 15°C to about 50°C for about between 60 to 120 minutes. Emptying all trapped air from inside the chamber to insure that the acid solution contacts all surfaces. Preferably, the acid soak is maintained at about 25°C for about 90 minutes.

4) Removing the quartz chamber from the acid tank and soaking same in rinse tank #1 for about 10 to 15 minutes. Again all trapped air should be removed from the internal area of the chamber to insure sufficient contact. Drain, clean and refill rinse tank # 1, and resubmerge the quartz chamber in the rinse tank at about several minutes' intervals, preferably about every 5 minutes, to facilitate effective fluid exchange in the interior of the chamber.

5) Repeat the above step 4 in rinse tank #2. 6) Inspecting the interior of the quartz-processing chamber for brown residue. In the event that any residue remains, the area is wiped with a DI water soaked polyester cloth wrapped about a rod to break-up any remaining deposits. The acid soak and rinsing steps are repeated until contaminants are substantially removed from the process chamber, and with the proviso that the quartz part may not be in contact with the acid solution for a time greater than six (6) cumulative hours. Substantially, as used herein mean at least 90% of residues are removed from the part, preferably more than 97%, and more preferably greater than 99% of residues are removed from the cleaned part.

7) Rinsing tanks #1 and #2 are completely drained and cleaned to insure that all further rinsing will be free of any metal contaminants. DI water that is used in all further rinsing is filtered to remove all particles down to 0.1 wm. All utensils that contact the rinse tanks and contents are rinsed with DI water.

8) Soaking the quartz chamber in rinse tank #1 for about 30 minutes. Preferably, the tanks are kept covered to prevent air particulates from contaminating the DI water. Again, assuring that all air is removed from the interior of the chamber. Drain and resubmerge the chamber in the rinse tank #1 at about 10 minute intervals.

9) Repeating the soaking in rinse tank #2 that is positioned in a clean room.

10) Rinsing the quartz processing chamber with isopropyl alcohol (IP A).

11) Blow drying the chamber with ionized clean dry air.

12) Packaging the cleaning chamber in a heat sealed poly bag.

[0023] The primary constituents of the rinse baths may include F^', NO₃ ^", SiF₆ ^'2 and GeF₆ ^"2, and as such, acid bath solution and rinse water should be disposed in an environmentally safe method.

[0024] Notably, an advantage of using concentrations in the 2% range provides for the ability to conduct the above-described cleaning process without benefit of an exhaust hood. The concentrations of the HF and HNO₃ are low enough that hazardous vapors of HF, HNO₃, NO and/or NO₂ do not accumulate at normal room exhaust rates.

[0025] In another aspect, the present invention provides for cleaning ceramic parts, including Minimal Overlap Exclusion Rings (MOER) that are contaminated with residue from process- related contaminants such as reagent residues, and degradation and reaction byproducts of reagents used in the active processing chamber. Contaminants are primarily aluminum fluoride and oxyfluoride. Tungsten and titanium oxides, fluorides and oxyfluorides are also present.

[0026] Initially, X-ray Photoelecton Spectroscopy (XPS) is performed to identify the chemical composition of the contaminant film and then the results are compared to that of a new or thoroughly cleaned ceramic part so that the contaminants and bulk ceramic compositions may be characterized.

[0027] Representative elemental compositions are presented in Table 1 in atomic percent.

Table 1 Elemental Analysis in Atomic Percent

[0028] Analysis of the chemical shifts of the XPS peaks listed above in Table 1 indicates that the contaminant film is composed primarily of aluminum trifluoride (A1F₃) with small amounts of oxyfluorides present in the general form AlO_xFy. Carbon, nitrogen, silicon, titanium, iodine and tungsten are also included in the deposits. [0029] The contamination of the ceramic material is removed by using a strong oxidizing agent containing a low concentration of a fluoride ion to aid in the dissolution of aluminum fluoride (as A1F₆ ^"3), silica (as SiF₆ ^"2), tungsten (as WOF₄), and titanium (as TiOF₄ ^"2). Preferably, the strong oxidizing agent includes, but is not limited to, nitric acid, permanganate, periodate, peroxides, peroxydisulfate, etc.

[0030] The cleaning process includes:

(a) air baking the ceramic material part for at a sufficient temperature and time to modify contaminant residue. Preferably, the ceramic part is baked in a muffle furnace at temperatures ranging from about 700°C to about 900°C, and more preferably about 850°C for about 45 to 120 minutes. The heating and cooling process should be moved in increments of approximately 75°C per hour. Thus the heating and cooling of the ceramic part is time consuming but it has been found by this inventor that this baking process modifies the contaminants sufficiently to allow the subsequent cleaning process step to be more effective.

(b) contacting the ceramic material part with a cleaning solution comprising an oxidizing agent and a fluoride ion containing compound, preferably the cleaning solution comprises and aqueous acid solution including nitric acid and hydrogen fluoride in a volume ratio of 1 : 1 : 1.

(c) rinsing the ceramic material part at least once with deionized water, preferably at least three rinsings to ensure removal of all acid cleaning solution from the ceramic material part; and

[0031] Yet another aspect of the present invention provides for a stripping process using a hot organic solvent that removes epoxy resin from ceramic substrates, such as digital mirror devices.

[0032] In the stripping process, the stripping solution comprises any organic solvent heated sufficiently to weaken the bonds between the epoxy resin and underlying contacting surface. Preferably, the organic solvent is an amine containing solvent and more preferably, N- methylpyrrolidone (NMP) is used. [0033] In the NMP treatment system, a covered container of sufficient size to enclose the semiconductor equipment part is used. The container may be fabricated from any material that remains uncorroded in the presence of NMP, and preferably the container is fabricated of heat resistant glass or stainless steel.

[0034] The depth of the covered container is sufficient to provide for numerous layers of a soft cloth, such as a polyester cloth, positioned on the bottom of the container. The soft cloth is soaked with the NMP solvent and then the device that requires removal of an epoxy resin is placed epoxy face side down on the soaked cloth. By placing the epoxy-containing surface directly on the soaked NMP cloth, a pathway is provided for free exchange of fresh solvent to and from the epoxy surface by thermal convention.

[0035] The solvent is heated to a temperature that shortens the time required to swell and soften the epoxy resin material and weaken existing bonds with the underlying surface. Preferably, the amine solvent is heated to temperature between 60°C to about 85°C, depending on the solvent. More preferably, the solvent of choice is NMP that is heated to about 70°C. The contacting time of the ceramic substrate is inversely related to the temperature of the swelling solvent, the concentration of the swelling and softening solvent, and the nature and extent of the epoxy resin on the surface.

[0036] The concentration of the hot N-methylpyrrolidone may be from about 75% to about 100%, and more preferably, about 100%. It should be noted that by maintaining a soaking process comprising 100% NMP at about 70°C, the time required to soften the epoxy resin is reduced from about 50 hours to about 60 minutes, relative to room temperature soaking.

[0037] The container may be heated by any known heating means including a resistance-heating device or a heating bath. Preferably, the heated container includes a thermocouple to monitor the temperature within the container and insure that the solvent is not heated to above the flash point of the solvent. For additional safety, a temperature controller may be connected to the thermocouple to automatically alert the user when a predetermined excess of temperature is sensed within the container.

[0038] In operation, the level of NMP solvent in the container is at least of sufficient quantity and depth to wet the surfaces having thereon an epoxy resin to be removed. In the alternative, the entire ceramic part may be in contact with the NMP solvent. Preferably, the ceramic part is soaked for about 30 to 90 minutes, and more preferably about 60 minutes. After a sufficient soaking period, the loosened epoxy film is wiped from the surface with a soft cloth. The process of the present invention provides for weakening of bonds between the epoxy resin and underlying surface and does not dissolve all the epoxy resin. However, because of the weakening of the epoxy bonds on the surface of the substrate, the epoxy resin is abraded from the ceramic substrate with the wiping process and introducing minimal damage to the wiped substrate.

[0039] After the ceramic substrate has cooled to room temperature, any residue of the NMP solvent remaining on the ceramic surface or within surface cervices is rinsed with a solvent that is compactable with NMP. NMP is a high boiling point liquid with a very low vapor pressure at room temperature, and as such, it will not evaporate from the surface of the cleaned and wiped surface in any reasonable time frame. A preferred solvent for NMP is acetone, because it has a high vapor pressure at room temperature and will rapidly exchange with NMP in the crevices of the cleaned ceramic substrate. However, it has been found that the solvent acetone can leaves stains on the cleaned ceramic substrate. As such, the acetone solvent is rinsed from the surface with a second solvent that does not suffer from the same staining forming problems as that of acetone. Preferably, the acetone rinsing is immediately followed by a rinsing with isopropyl alcohol IPA to eliminate the possible formation of any stains on the ceramic substrate and IPA evaporates rapidly leaving a stain free surface.

[0040] Preferably, the multiple solvent rinsings are performed using a spraying technique thereby washing contaminants away from the surface of the ceramic substrate, instead of soaking because soaking requires multiple rinse exchanges to prevent the retention of NMP residues on the surface of the ceramic substrate.

[0041] After the multiple rinsings, the ceramic equipment part is air dried or dried by a stream of clean dry air. To insure that any NMP solvent that may have been absorbed into the ceramic substrate is removed, the equipment part is vacuum baked at a sufficient temperature and vacuum to draw off any remaining NMP sequestered in the porous ceramic surface. Preferably, the part is placed in a vacuum oven and heated to temperature of about 90°C to about 120°C while maintaining the oven at a vacuum less than about 5 torr, and more preferably at a vacuum less that about 1 torr. The ceramic part is baked for a sufficient time to remove solvent residue from the pores of the ceramic material, preferably from about 45 to 90 minutes, and more preferably about 60 minutes. The cleaned part is subsequently cooled and prepared for packaging or reintroduction into the processing tool.

[0042] The features and advantages of the invention are more fully shown by the following non- limiting examples.

EXAMPLE 1

[0043] A ceramic 0.7 SVGA digital mirror device from Texas Instrument was cleaned by the process steps set out below.

1) The digital mirror device as shown in Figure 4 A illustrates the contact pad on the ceramic substrate wherein the epoxy bond pad is clearly observable as a brown strip down the middle of the substrate.

2) The device was soak, epoxy contaminated face down in a cloth soaked in 100% N- methylpyrrolidone at 70°C for 60 minutes.

3) The weakened epoxy residue was wiped off the substrate with a soft polyester cloth.

4) The device was thoroughly rinsed with acetone at ambient temperature, which as used herein is preferably room temperature, and then rinsed with isopropyl alcohol.

5) The device was air-dried and then baked under less than 1 torr vacuum pressure at 100°C for 60 minutes.

6) The device was cooled to room temperature.

[0044] After the device was cooled, the window and cleaned surface were inspected to determine the efficacy of the cleaning process. No visible epoxy residue remained on the surface of the substrate. The gold bond pads and other metal surfaces on the device showed no visible signs of corrosion or any chemical changes as shown in Figure 4B. No optical change was visible in the transparent window. [0045] To insure that the solvents used in the epoxy stripping process did not affect the antireflective coating on the window of the digital mirror device, the optical transmission of a test window was tested before and after exposure to the solvents. The parts used for this test were windows mounted in gold plated Kovar frames. One of the windows was soaked in NMP and then rinsed with acetone and IPA using the same exact process parameters as specified in the above epoxy removal procedure. All solvents were allowed to contact both sides of the window. Visible and ultraviolet transmission spectra were taken of the solvent treated window and three untreated windows at normal incidence using a double beam spectrometer.

[0046] Results are shown in Figure 5. The black line in the figure represents the transmission spectra of the NMP treated window. Figure 5 also shows that the transmission spectra of the NMP treated window are virtually identical to that of the untreated windows. Thus, it was shown that solvent exposure did not damage the antireflective coating on the window. Interestingly, it was found that at wavelengths between 700 and 950 nm, the transmission of the NMP treated window was up to 0.4% greater that the transmission of the untreated windows.

[0047] The equipment part is an aluminum oxide ceramic and known to have significant porosity. A possible consequence of this porosity is diffusion of NMP into the ceramic material during the epoxy stripping process. If the NMP is not subsequently removed, the NMP might then diffuse back into the substrate-epoxy interface as a function of time leading to premature weakening and possible failure of the epoxy bond. As such, tests were conducted to determine the extent of the solvent penetration into the pores of the ceramic and whether the vacuum baking removed the residual NMP solvent. To evaluate the extent of NMP penetration into the ceramic as a result of the epoxy removal process, a NMP substrate and an untreated substrate were examined using dynamic secondary ion mass spectroscopy (SIMS) which measures the relative composition of the material as a function of depth by sputtering a crater into the material with cesium ions and analyzing the ejected elemental and molecular ions by mass spectroscopy.

[0048] The test coupons used in the SIMS depth profile experiments were cut using a dry diamond saw from a digital mirror device that had not been previously exposed to the epoxy removing treatment of the present invention. After cutting, all the coupons were rinsed with solvent to remove all remaining debris. NMP treated coupons were soaked in hot NMP and then rinsed with acetone and IPA with the exact same parameters specified above. One control coupon and one NMP treated coupon were vacuum baked to determine the efficiency of the present process for the removal of residual solvent from the pores of the ceramic.

[0049] Plots of ion current as a function of sputter depth for mass 14 (nitrogen) as a function of depth are shown in Figure 6 for the as received, NMP treated, vacuum baked, and vacuum baked control coupons. As shown, after NMP treating, the amount of nitrogen present in the subsurface region increased by roughly a factor of eight. This increase is due to the absorption into the pores of the ceramic. Interestingly, the depth of the penetration of the NMP nitrogen appears to be only about 80 A. After vacuum bakeout, the subsurface nitrogen introduced by the NMP treatment was reduced to less than 0.1% of its original value. Even the residual nitrogen present on the as-received coupon was reduced to less than 1% of its initial value by the vacuum baking process.

[0050] Thus, it was shown that after NMP exposure, the amount of organic nitrogen increased by at least a factor of eight and advanced in depth from about 60 to about 80 A. It was further shown that by vacuum baking the device, the surface nitrogen was reduced to a value less than 0.1% of the amount introduced by the NMP treatment.

[0051] Ion current for mass 13 (CH⁺ hydrocarbon fragment) as a function of depth is shown in Figure 7 for the as received coupon, NMP treated coupon, vacuum baked coupon, and vacuum bake control coupon. This is the only ion fragment in addition to nitrogen at mass 14 that exhibited a large increase in ion current as a result of the NMP treatment. At depths less than 80 A, the results obtained at mass 13 are very similar to those obtained at mass 14, confirming that the nitrogen introduced into the ceramic as a result of the NMP treatment is organic nitrogen. However, above 80 A, the mass 13 ion current does not fall to zero as the mass 14 and other hydrocarbon ions do. On the NMP treated coupon, the mass 13 ion current persists at a low slowly decaying level out to about 950 A. It is possible that the persistent mass 13 ion signal is due to the penetration of some small hydrocarbon molecule deep within the pore structure of the ceramic. However, it is more likely that this residual mass 13 signal arises from the reaction of atomic hydrogen with carbidic impurities in the ceramic during the sputtering process. Such ion reactions are commonly observed in dynamic SIMS due to the high ion density present in the sputter crater. Atomic hydrogen has a much greater mobility in solid matrices than other molecular species and should move in and out of the ceramic to a much greater extent than other materials would. The observation of excess hydrogen only in the NMP treated coupon suggests that some NMP decomposition occurred in the pores of the ceramic during the hot solvent treatment. Whatever the cause, it is clear from Figure 7 that all this foreign material was eliminated from the ceramic during the vacuum bake step. In fact, baking under vacuum consistently produced a substantial decrease in ion current at every contaminant mass examined in this study.

[0052] While the invention has been shown and described with reference to specific features, aspects and embodiments herein, it will be appreciated that the invention is susceptible of a wide variety of other embodiments, features and implementations consistent with the disclosure herein, and the invention and claims hereafter set forth are therefore to be broadly construed and interpreted, within the spirit and scope of the foregoing disclosure.

Claims

THE CLAIMSWhat is claimed is:

1. A cleaning process for a quartz process chamber to remove contaminant residue, the process comprising the steps of:

(a) contacting the quartz process chamber with an aqueous acid solution;

(b) removing the quartz process chamber from the aqueous acid solution;

(c) rinsing the quartz process chamber with deionized water

(d) repeating steps a-d until contaminant residue is substantially removed from process chamber; and

(e) drying the quartz process chamber.

2. The process of claim 1, wherein the aqueous acid solution of step (a) comprises hydrofluoric acid and nitric acid.

3. The process of claim 1 , wherein the quartz processing chamber is dried using ionized clean dry air.

4. The process of claim 2, wherein the amount of hydrofluoric acid in said solution is from about 2% to about 5% by weight, based on the total weight of the solution, and the amount of nitric acid in said solution is from about 2% to about 5% by weight, based on the total weight of the solution.

5. The process of claim 2, wherein the amount of hydrofluoric acid in said solution is about 2% by weight, based on the total weight of the solution, and the amount of nitric acid in said solution is about 2% by weight, based on the total weight of the solution.

6. The process of claim 1, wherein step (a) is carried out at temperature in the range of from about 15°C to about 50°C.

7. The process of claim 2, wherein step (a) is carried out at temperature 25°C.

8. The process of claim 2, wherein step (a) is carried out for a contacting time of from about 60 to 120 minutes.

9. The process of claim 2, wherein the contaminant on the quartz processing chamber comprises a contaminant species selected from the group consisting of partially fluorinated hydrocarbons, elemental silicon, elemental germanium, the common air formed oxides of silicon and germanium, free iron, oxide scale, rust, grease, oil, carbonaceous and other residual chemical films, soil, particles, metal chips, and dirt.

10. The process of claim 1, wherein the contacting step (a) is carried out for a contacting time of 90 minutes.

11. The process of claim 1 , wherein the contacting step (a) is carried out for not longer than six cumulative hours.

12. The process of claim 2, wherein the rinsing step (b) includes soaking of the quartz process chamber in a rinse tank for about 10 to about 15 minutes.

13. The process of claim 2, wherein the rinsing step further comprises multiple dippings in a drained, cleaned and refilled rinse tank.

14. The process of claim 2, wherein deionized water used for rinsing is filtered to substantially remove all particles down to 0.1 Mm.

15. The process of claim 1, wherein the cleaned quartz processing chamber is dried and packaged.

16. A process for cleaning a ceramic material part to remove contaminant residue, the process comprising the steps of

(a) air baking the ceramic material part for at a sufficient temperature and time to modify contaminant residue; (b) contacting the ceramic material part with a cleaning solution comprising an oxidizing agent and fluoride ion containing compound;

(c) rinsing the ceramic material part; and

17. The process according to claim 16, wherein the oxidizing agent is selected from the group consisting of nitric acid, permanganate, periodate, peroxides, and peroxydisulfate.

18. The process according to claim 16, wherein the fluoride ion containing compound is HF.

19. A process for removing epoxy resin from a ceramic substrate, the process comprising the steps of: a) contacting the ceramic substrate with heated N-methylpyrrolidone for a sufficient time to swell and mechanically weaken the bonding of the epoxy resin to the ceramic substrate;

b) wiping the epoxy resin from the ceramic substrate;

c) rinsing the ceramic substrate with at least one organic solvent; and

d) vacuum baking the ceramic substrate at a sufficient temperature and time period to remove substantially all solvent residues from the ceramic substrate.

20. The process of claim 19, wherein the heated N-methylpyrrolidone is at temperature in a range of from about 60°C to about 85°C.

21. The process of claim 19, wherein the heated N-methylpyrrolidone is at temperature of about 70°C.

22. The process of claim 19, wherein the ceramic substrate comprises a digital mirror device.

23. The process of claim 20, wherein the ceramic substrate is formed of a material comprising aluminum oxide.

24. The process of claim 22, wherein the heated N-methylpyrrolidone is applied to the ceramic substrate by contacting the substrate with an applicator soaked with the N-methylpyrrolidone.

25. The process of claim 23, wherein step (a) is carried out for a contacting time of from about 30 to about 90 minutes.

26. The process of claim 23, wherein step (a) is carried out for a contacting time of about 60 minutes.

27. The process of claim 19, wherein the concentration of the heated N-methylpyπolidone is about 75% to about 100%.

28. The process of claim 19, wherein the concentration of the heated N-methylpyrrolidone is about 100%).

29. The process of claim 19, wherein the rinsing step comprises rinsing with a first organic solvent that is compatible with the N-methylpynolidone and then rinsing with a second organic solvent.

30. The process of claim 29, wherein the first organic solvent comprises acetone and the second organic solvent comprises isopropyl alcohol.

31. The process of claim 30, wherein the acetone and isopropyl alcohol are used at room temperature.

32. The process of claim 19, wherein the weakened epoxy resin is wiped from the ceramic substrate by a cloth.

33. The process of claim 19, wherein the ceramic substrate comprises aluminum oxide.

34. The process of claim 19, further comprising air drying the ceramic substrate before vacuum baking.

35. The process of claim 19, wherein the ceramic substrate after step (d). is packaged.

36. The process of claim 34, wherein the ceramic substrate is packaged in a polymeric heat- sealed packaging.

37. The process of claim 19, wherein the ceramic substrate is cooled to ambient temperature prior to step (c).

38. The process of claim 19, wherein vacuum baking of the ceramic substrate is conducted at a vacuum pressure less than 5 torr.

39. The process of claim 19, wherein vacuum baking of the ceramic substrate is conducted at a vacuum pressure less than 1 torr.

40. The process of claim 19, wherein the ceramic substrate is placed in a vacuum oven maintained at temperature in a range of from about 90°C to about 120°C.

41. The process of claim 19, wherein the ceramic substrate is placed in a vacuum oven maintained at temperature of about 100°C.

42. The process of claim 40, wherein the ceramic substrate is placed in a vacuum oven for about 45 to about 90 minutes.

43. The process of claim 40, wherein the ceramic substrate is placed in a vacuum oven for about 60 minutes.

44. A method of increasing the operating life of a semiconductor processing tool, in which the semiconductor manufacturing tool comprises a quartz substrate part that is contaminated with contaminant species deriving from a semiconductor process, the method comprising:

(a) submerging the quartz substrate part in a tank containing an aqueous acid solution; (b) removing the quartz substrate part from the acid tank;

(c) submerging the quartz substrate part in a rinse tank containing deionized water;

(d) draining and refilling the rinse tank at least one to facilitate effective fluid exchange in any interior area of the quartz substrate part;

(e) repeating steps a-d until residue is substantially removed from the quartz substrate part; and

(f) drying the quartz substrate part.

45. The process of claim 43, wherein the amount of hydrofluoric acid in said solution is from about 2% to about 5% by weight, based on the total weight of the solution, and the amount of nitric acid in said solution is from about 2% to about 5% by weight, based on the total weight of the solution.

46. The process of claim 44, wherein the amount of hydrofluoric acid in said solution is about 2% by weight, based on the total weight of the solution, and the amount of nitric acid in said solution is about 2% by weight, based on the total weight of the solution.

47. The process of claim 43, wherein step (a) is carried out at temperature in a range of from about 15°C to about 50°C.

48. The process of claim 44, wherein step (a) is carried out at 25°C.

49. The process of claim 44, wherein step (a) is carried out for a contacting time of about 60 to 120 minutes.

50. The process of claim 44, wherein the contaminant on the quartz substrate part comprises a contaminant species selected from the group consisting of free iron, oxide scale, rust, grease, oil, carbonaceous and other residual chemical films, soil, particles, metal chips, and dirt.

51. The process of claim 143 wherein the contacting step (a) is carried out for a contacting time of 90 minutes.

52. The process of claim 43, wherein the contacting step (a) is carried out for not longer than six cumulative hours.

53. The process of claim 44, wherein the rinsing step (b) includes soaking of the quartz process chamber in a rinse tank for about 10 to about 15 minutes.

54. The process of claim 44, wherein the rinsing step further comprises multiple dippings in a drained, cleaned and refilled rinse tank.

55. The process of claim 44, wherein deionized water used for rinsing is filtered to remove substantially all particles down to 0.1 urn.

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56. The process of claim 43, wherein the cleaned quartz substrate part is dried and packaged.

57. The process of claim 43, wherein the cleaned quartz substrate part is dried with ionized clean dry air.

58. A method of determining amenability of a ceramic surface of a semiconductor equipment part to soaking with a solvent treatment to remove epoxy resin, wherein the soaking treatment includes exposure of the ceramic surface to N-methylpyrrolidone, said method comprising:

contacting the ceramic surface with N-methylpyrrolidone of at least the same strength as that involved in said soaking treatment followed by vacuum baking of the part;

determining whether ceramic surface releases N-methylpyrrolidone during the vacuum baking step; and

contraindicating the surface as amenable to the treatment with N-methylpyrrolidone if absorption of N-methylpyrrolidone remains at depths greater than 60 A after vacuum baking.