JP2006528840A - Mask cleaning - Google Patents

Abstract

A method and apparatus for cleaning a mask is described. In one embodiment, the present invention is a method of cleaning a mask. The method includes placing a mask in a cleaning solution. The method also includes stirring the clean solution for a predetermined time at a predetermined stirring level.
[Selection] Figure 5

Description

Field

  The present invention relates to the field of semiconductor processing. More particularly, the present invention relates to cleaning masks used in semiconductor processing.

background

  One form of semiconductor device uses C-bump technology to connect the semiconductor device and external circuitry. To form the conductor used in the C-bump technology, a mask is placed directly on the integrated circuit wafer and a conductive metal is deposited at a location determined by the mask on the integrated circuit. C-bump technology allows faster and more frequent connection of integrated circuits and external circuit components (such as other integrated circuits or other devices). However, C-bump technology requires a complex and tightly controlled manufacturing process to achieve these results.

  As expected, these masks have strict tolerances. In one process, the holes in the mask are defined to be 4 mils (101.6 μm) in diameter with 1% tolerance. Furthermore, each time the mask is used, it must be cleaned without changing the hole dimensions beyond process tolerances. Of course, mask cleaning is a troublesome problem.

  Furthermore, depending on the process, the mask must be used and cleaned multiple times, in some instances as many as 10 times / 1 mask. Therefore, a cleaning process that provides relatively small changes to the mask holes is beneficial. Furthermore, it is known that semiconductor manufacturing plants are operating 24 hours / day, 7 days / week. As a result, a quick cleaning process is beneficial. Furthermore, mask cleaning is an additional manufacturing expense. If the cleaning cost is too high compared to the mask replacement cost, cleaning is not cost effective. In some cases, cleaning the mask 10 times must be less expensive than the replacement cost of the mask being cleaned to be usable. As a result, an inexpensive cleaning process is beneficial.

  FIG. 1 is a diagram illustrating an embodiment of a prior art mask that may require cleaning. The mask 110 has a number of holes precisely positioned to allow conductive bumps to be formed at desired locations on the integrated circuit. In one embodiment, the mask 110 is fabricated from molybdenum, which is a relatively dense element. The holes 170 are arranged at predetermined positions on the mask 110 as a regular array or at irregular intervals. In one embodiment, the holes 170 are arranged as a regular array with a distance S between adjacent holes. In some embodiments, the distance S may be required to be about 120 μm, and each hole may be required to be about 101.6 μm in diameter. Thus, cleaning the mask 110 is a difficult and rigorous operation. FIG. 2 shows an embodiment of the prior art mask of FIG. 1 when viewed as a cross-sectional view along line AA, with no deposited material on the mask. The mask 110 shown in FIG. 2 is made by cleaning a previously deposited material, or is unused. In one embodiment, D1 after being cleaned must be within 1% of D1 before being cleaned, or 101.6 μm +/− 1 μm. Furthermore, in another embodiment, D1 after being cleaned is within 0.1% of D1 before being cleaned, or 101. Must be 6 μm +/− 0.1 μm. As shown, D2 is the outer diameter of the hole and may similarly have similar tolerances to changes in diameter.

  FIG. 3 shows an embodiment of a mask according to the prior art when viewed as a cross-sectional view along the line AA, with the deposited material on the mask. Mask 110 is a mask designed to contact a semiconductor device to pattern a conductor deposited on the semiconductor device. Although the drawing shown in FIG. 3 is not shown to scale, the mask 110 is a relatively thin disk-like having holes that penetrate it precisely with many regular spacings. It is required to be a plate.

  In FIG. 3, layers 120, 130, 140, and 150 are depicted as being deposited on mask 110. Layer 120 is a chromium (Cr) layer that is required to adhere well to the integrated circuit. Layer 130 is a copper (Cu) layer that is required to conduct electricity well. Similarly, layer 140 is a gold (Au) layer that is required to conduct electricity well. Layer 150 is a lead / tin (Pb / Sn) solder layer that is required to conduct electricity well and to bond well to the outer conductor.

  These layers are deposited on the backside of the semiconductor at locations defined by holes that penetrate the mask 110, such as the hole shown in the center of FIG. 2 or FIG. In one embodiment, the holes in the mask 110 are defined to be 101.6 μm wide with 1% tolerance (as indicated by D1 in FIG. 2). Shown in FIG. 4 is a cross-sectional view of a prior art mask along line AA after improperly cleaning mask 110. Due to over-etching, D1 'is too wide at this point, and D2' is too wide, so that the mask 110 exceeds the specified tolerances used in manufacturing. Become. Such inadequate cleaning makes the mask 110 unusable and in some cases the production line must create a new mask before resuming work.

  In general, cleaning or etching in semiconductor processes is performed using a variety of materials or solvents, including a variety of organic or inorganic acidic or alkaline solutions. Desirable etch rates that allow fabrication in a reasonable time to achieve the objective (such as actually cleaning the mask) without over-etching are difficult to predict without experimentation. Various acids or bases work well for some metals, but may not work well for other metals due to the reaction between the etching ions and the metal to be cleaned.

  In addition, in some cases, assisted etching may be used, but the energy applied during the assisted etching may generate higher energy atoms and turbulence at the surface of the etching bath, so that from the etching bath. It causes problems with the corrosive vapors that are generated and correspondingly increases the suspended matter from the etch bath. It should be noted that one process involves etching using an acid with an assisting electrolyte. Unfortunately, this requires caution in selecting the metal to etch because electroplating and exothermic reactions can occur depending on the relationships between the metals involved. Electroplating can enhance the bond that cleaning typically removes, and the exothermic reaction creates safety problems. Choosing the right kind of solvent and the right way to assist (if necessary) for a given etching process is not a simple or obvious task.

Overview

  A method and apparatus for cleaning a mask is described. In one embodiment, the present invention is a method of cleaning a mask. In some embodiments, the present invention includes placing the mask in an etching solution and agitating the solution to etch away the material deposited on the mask. In another embodiment, the present invention provides a first container comprising an etching solution, a second solution holding the first container in the second solution, and agitation coupled or connected to the second container. Including a bowl. In yet another embodiment, the present invention includes placing the mask in an etching solution to etch away the material deposited on the mask, and scrub the mask periodically. May be included.

  In one embodiment, the present invention is a method for cleaning a molybdenum mask having a series of metals deposited thereon. The method includes placing a molybdenum mask in a cleaning solution containing hydrochloric acid. The method also includes removing the molybdenum mask from the cleaning solution after a predetermined time. The molybdenum mask may have a set of through holes.

  In a further embodiment, the present invention is an apparatus for cleaning a mask. The apparatus includes a first container having an open top. The apparatus also includes a second container having an open top, the second container containing the first container. The apparatus further includes a stirrer in the second container. Alternatively, the agitator may be coupled to the second container or may be in contact with the outside of the second container.

  In another embodiment, the present invention is a method for cleaning a mask. The method includes placing a mask in a cleaning solution. The method also includes stirring the clean solution for a predetermined time at a predetermined stirring level.

  In yet another embodiment, the present invention is an apparatus for cleaning a mask. The apparatus includes a first means for cleaning the mask. The apparatus includes a second means for holding the mask. The apparatus also includes a third means for stirring the first means and the second means. The apparatus further includes fourth means for including the first means. The apparatus also includes a fifth means for surrounding the fourth means. The apparatus further includes sixth means for holding fifth means and third means.

  In yet another embodiment, the present invention is a method for cleaning a mask. The method includes placing a mask in a container. The method also includes placing the container in a cleaning solution. A cleaning solution is contained in the first container. The first container is accommodated in the second container. The second container includes an aqueous solution surrounding the first container.

  In yet another embodiment, the present invention is a method of cleaning a molybdenum mask having a series of metals deposited thereon. The present invention includes placing a molybdenum mask in a cleaning solution. The method also includes removing the molybdenum mask from the cleaning solution after a predetermined time. The method may further comprise agitating the cleaning solution for a predetermined time at a predetermined agitation level. The series of metals may include chromium, copper, gold, and lead / tin mixtures.

  The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the following description, serve to explain the principles of the invention. It should be understood that the drawings are for purposes of illustrating the invention rather than limiting the invention.

Detailed description

  A method and apparatus for cleaning a mask is described. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details. In other instances, structures and devices are shown in block diagram form in order to avoid obscuring the present invention.

  In some embodiments, the present invention includes placing the mask in an etching solution and stirring the solution to remove the material deposited on the mask by etching. In another embodiment, the present invention provides a first container comprising an etching solution, a second container that holds the first container in the second solution, and agitation coupled or connected to the second container. Including a bowl. In yet another embodiment, the present invention includes placing the mask in an etching solution to etch away the material deposited on the mask and periodically scrub the mask. May be included.

  In one embodiment, the present invention is a method for cleaning a molybdenum mask having a series of metals deposited thereon. The method includes placing a molybdenum mask in a cleaning solution containing hydrochloric acid. The method also includes removing the molybdenum mask from the cleaning solution after a predetermined period of time. The molybdenum mask may have a set of through holes.

  In another embodiment, the present invention is an apparatus for cleaning a mask. The apparatus includes a first container having an open top. The apparatus also includes a second container having an open top, the second container containing the first container. The apparatus further includes a stirrer in the second container. Alternatively, the agitator may be coupled to the second container or may be in contact with the outside of the second container.

  In another embodiment, the present invention is a method for cleaning a mask. The method includes placing a mask in the cleaning solution. The method also includes agitating the clean solution for a predetermined period of time at a predetermined agitation level.

  In yet another embodiment, the present invention is an apparatus for cleaning a mask. The apparatus includes a first means for cleaning the mask. The apparatus includes a second means for holding the mask. The apparatus also includes a third means for stirring the first means and the second means. The apparatus further includes a fourth means for housing the first means. The apparatus also includes a fifth means for surrounding the fourth means. The apparatus further includes sixth means for holding fifth means and third means.

  In yet another embodiment, the present invention is a method for cleaning a mask. The method includes placing a mask in a container. The method also includes placing a container in the cleaning solution. The cleaning solution is contained in the first container. The first container is accommodated in the second container. The second container contains an aqueous solution surrounding the first container.

  In yet another embodiment, the present invention is a method of cleaning a molybdenum mask having a series of metals deposited thereon. The present invention includes placing a molybdenum mask in the cleaning solution. The method also includes removing the molybdenum mask from the cleaning solution after a predetermined period of time. The method may further include agitating the cleaning solution for a predetermined period of time at a predetermined agitation level. The series of metals may include chromium, copper, gold, and lead / tin mixtures.

  FIG. 5 is an embodiment of a cleaning system. After some experiments, the mask 110 and similar masks may be cleaned using an etch solution, and assisted etching has been found to be beneficial. The first or internal container 310 contains the etching solution 320 and is covered by a cap 330. A wafer boat 340 is disposed in the inner container 310, and the wafer boat 340 holds a mask such as the mask 110. Preferably, the wafer boat 340 holds several masks simultaneously, allowing fluid to contact the mask surface.

  The inner container 310 is supported by a base 360 disposed on the bottom surface of the outer or second container 350. The container 350 contains the aqueous solution 370 and may be covered with a cap 380. The outer container 350 is supported by a stirrer 390, and the stirrer 390 may be, for example, a slab attached to a vibration mechanism. Accordingly, the etching solution or cleaning solution 320 may be agitated by using the agitator 390, and the vibration of the agitator is transmitted to the container 350, the base 360, and the container 310. The stirrer 390 may be evaluated based on the frequency of vibration or based on power output via vibration.

  FIG. 6 is an embodiment of a wafer holder that holds a mask when viewed along line BB in FIG. The wafer holder 410 may be used as a part of the wafer boat 340 of FIG. 3, for example. Wafer holder 410 includes a protrusion 420, a latch 430, and a hinge portion 440. In one embodiment, the wafer holder 410 is manufactured from Teflon®. In another embodiment, the wafer holder 410 is made from high density polyethylene. In any embodiment, the wafer holder 410 may be required to have a groove (such as a v-shaped groove) into which the mask 110 can fit. Such grooves may exist along one or more inner surfaces of the wafer holder 410, allowing for a sliding fit and a tight seal of the mask to prevent the mask from bending.

  FIG. 7 is a further drawing illustrating an embodiment of the wafer holder when viewed along line CC in FIG. The groove 450 is shown as part of the inner surface of the wafer holder 410. FIG. 8 is yet another drawing showing the wafer holder embodiment in a perspective view. Wafer holder 410A (including protrusion 420A, latch 430A, and hinge 440A) is connected to second wafer holder 410B (including protrusion 420B, latch 430B, and hinge 440B). Wafer holders 410A and 410B together constitute a whole or part of a wafer boat such as wafer boat 340. It should be noted that the exact shape of the wafer holder 410 may vary widely within the spirit and scope of the wafer holder of the present invention.

  The cleaning system and wafer holder may be used in various ways. FIG. 9 is an embodiment of the process of the cleaning mask. At block 510, a mask to be cleaned is received from, for example, a production line. At block 520, the external container of the cleaning system or apparatus is filled with, for example, deionized water. At block 530, the inner container of the cleaning device is filled, for example, with an etching solution, and the inner container is placed in the outer container. At block 540, the mask is placed in a container such as a mask holder or wafer holder. At block 550, the container is placed in the inner container, thereby immersing the mask in the etching solution. At block 560, the inner vessel is capped, thereby reducing etch solution fumes or leaking molecules.

  In block 570, the cleaning system is agitated and incorporates energy into the system, potentially increasing the etch rate of the etching solution. After a predetermined time, at block 580, the container is removed from the inner container. At block 590, the mask is washed with deionized water. At block 595, the mask is dried with nitrogen. In this way, a mask having no material deposited on top is obtained.

  Note that agitation may not be used. FIG. 10 is a diagram illustrating another embodiment of a process for cleaning a mask. In block 610, the mask to be cleaned is received from, for example, a production line. At block 620, the outer container of the cleaning system or cleaning device is filled, for example, with deionized water. At block 630, the inner container of the cleaning system is filled with, for example, an etching solution. The inner container may be disposed in or attached to the outer container. At block 640, the mask is placed in a container such as a mask holder or wafer holder. At block 650, the container is placed in the inner container, thereby immersing the mask in the etching solution.

  At block 655, the inner container is capped, thereby reducing etch solution fumes or leaking molecules. After a predetermined time, at block 660, the inner container is opened or uncovered to allow access to the mask. At block 665, the container is removed from the inner container. At block 670, the mask is scrubbed to remove any film (such as a protective film or passivation film) that may have been formed. At block 675, a determination is made as to whether the mask is clean. If not, the process returns to block 650 and the container is again placed in the inner container.

  If the mask is clean, at block 680, the mask is washed with deionized water. At block 690, the mask is dried with nitrogen. In this way, a mask having no material deposited on top is obtained. Different etching solutions may or may not require scrubbing or agitation, and different times may be appropriate depending on the material deposited on the mask. Note that this is not possible.

  In one embodiment, an etching solution consisting of hydrochloric acid (HCl) was used. Various concentrations of hydrochloric acid ranging from about 10% to about 37% by weight were tested. A concentration of about 37% has been found to be particularly effective with agitation. Etching for about 20 minutes with a liquid with a concentration of 37% and a stirring power of about 25 W / gallon is deposited on the mask without much damage to the mask (within the range of +/− 0.1 μm). The material was removed quickly. The damage to the mask was examined with SEM (scanning electron microscope).

  Various different power settings of the agitator were tried, ranging from about 5 W / gallon liquid to about 50 W / gallon liquid. For example, stirring power at higher levels, such as 100 W / gallon, may be used. Similarly, the etch time was examined in the range of minutes to 40 minutes or more, and the temperature was examined in the range from about room temperature (25 ° C.) to about 40 ° C.

  In another embodiment, an etching solution consisting of hydrochloric acid was used. Hydrochloric acid was found to be most effective at about 37% by weight. Agitation was not used. The Pb / Sn layer has a tendency to bond with chloride, forming an insoluble material, so that the mask was found to take significantly more than 20 minutes to achieve a clean etch (in some cases, About 20 hours).

  In yet another embodiment, an etching solution consisting of hydrochloric acid was used. Hydrochloric acid has been found to be most effective at a weight concentration of about 37%. Agitation was not used. It has been found that the Pb / Sn layer tends to bond with chloride and forms an insoluble material, so that the mask must be repeatedly scrubbed to achieve a clean etch. The entire process took significantly longer than 20 minutes, but was still found to be 20 hours or less.

  In yet another embodiment, an etching solution consisting of hydrochloric acid and acetic acid was used. Hydrochloric acid was tested as low as 90% by weight (hydrochloric acid: acetic acid = 9: 1), but was found to be most effective at a weight concentration of about 99% of the total acid in the etching solution. Agitation was not used. It has been found that the Pb / Sn layer tends to bond with chloride, so that the mask takes significantly more than 20 minutes (in some cases about 20 hours) to achieve a clean etch.

Other examples

  Various other etching solutions have been tried. These included nitric acid (HNO3), phosphoric acid (H2PO4), hydrofluoric acid (HF), sodium hydroxide (NaOH), sulfuric acid (H2SO4), and hydrogen peroxide (H2O2). In addition, an electrolyte (using an electric field between the mask and the electrode in solution) was used with various bases. These acids and bases have different results for the specific combination of metals used, and some have shown the potential to be beneficial with various combinations of metals. Concentrations ranged from about 5% to about 99.9%, and various concentrations were tested for each acid. Several ranges of concentrations tested are listed in the following table.

  Each of these acids has been found to have varying degrees of effectiveness. It should be noted that agitation may be evaluated or set as a function of the frequency of vibration, and frequencies present in the range of 25-40 kHz have been found to be particularly effective. It should also be noted that wafer boats may be formed in a variety of ways, and both boat and top designs and clamshell designs are potentially useful. From the foregoing, it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without departing from the spirit and scope of the invention. In some instances, references have been made to features that may be present in various embodiments or some embodiments, but likewise, these features do not necessarily limit the spirit and scope of the present invention. Although structures are provided in the drawings and specification, the structures may be formed or assembled in other ways that are within the spirit and scope of the invention. Similarly, although the methods have been illustrated and described as linear processes, such methods may have rearranged operations or operations performed in parallel within the spirit and scope of the present invention. . Thus, the present invention is limited only by the accompanying claims.

1 is a diagram showing an embodiment of a mask according to the prior art. FIG. 2 is a cross-sectional view taken along line AA of the prior art mask embodiment shown in FIG. 1 and does not include a deposited material on top. FIG. 2 is another view showing the embodiment of the prior art mask shown in FIG. 1 in a cross-sectional view along line AA, with the material deposited on top. 2 is a cross-sectional view taken along line AA of the prior art mask embodiment shown in FIG. 1 after material has been inappropriately removed by cleaning. FIG. It is a figure which shows embodiment of the cleaning system. FIG. 6 is a view of an embodiment of a wafer holder holding a mask, taken along line BB in FIG. 5. FIG. 7 is another view of the wafer holder embodiment taken along line CC in FIG. 6. FIG. 5 is another view showing an embodiment of the wafer holder in a perspective view. 6 is a flowchart illustrating an embodiment of a process for cleaning a mask. 6 is another flowchart illustrating an embodiment of a process for cleaning a mask.

Explanation of symbols

DESCRIPTION OF SYMBOLS 310 ... 1st container, 320 ... Etching solution, 330 ... Cap, 340 ... Wafer boat, 350 ... 2nd container, 360 ... Base, 370 ... Aqueous solution, 380 ... Cap, 390 ... Stirrer

Claims (115)

A method of cleaning a molybdenum mask having a series of metals deposited thereon,
Placing a molybdenum mask in a cleaning solution containing hydrochloric acid;
Removing the molybdenum mask from the cleaning solution after a predetermined time;
A method comprising:   The method of claim 1, further comprising agitating the cleaning solution for a predetermined amount of time at a predetermined agitation level. Further comprising the step of placing the molybdenum mask into the container;
The method of claim 2, wherein placing the molybdenum mask in the cleaning solution comprises placing a container in the cleaning solution.   The method of claim 3, further comprising the step of closing the container. A cleaning solution is contained in the first container;
A first container is contained in a second container;
The method of claim 4, wherein the second container further contains an aqueous solution surrounding the first container.   The method of claim 5, further comprising covering the first container with a lid.   The method of claim 6, further comprising the step of drying the mask with nitrogen.   The method of claim 7, further comprising the step of cleaning the mask with deionized water.   9. The method of claim 8, wherein the cleaning solution is a hydrochloric acid solution having an acid concentration of at least 5%.   The method of claim 9, wherein the cleaning solution is a hydrochloric acid solution having an acid concentration of at least 15%.   11. The method of claim 10, wherein the cleaning solution is a hydrochloric acid solution having an acid concentration that is at least 25% and at most 50%.   The method of claim 11, wherein the cleaning solution is a hydrochloric acid solution having an acid concentration of about 37%.   9. A method according to claim 8, wherein the predetermined time is at least 5 minutes and at most 300 minutes.   The method of claim 13, wherein the predetermined time is at least 10 minutes and at most 100 minutes.   15. A method according to claim 14, wherein the predetermined time is at least 15 minutes and at most 40 minutes.   16. The method of claim 15, wherein the predetermined time is at least 25 minutes and at most 30 minutes.   The method of claim 8, wherein the agitation level is quantified by agitation frequency.   The method of claim 17, wherein the agitation frequency is between 18 kHz and 2 MHz.   The method of claim 18, wherein the agitation frequency is between 20 kHz and 1 MHz.   The method of claim 19, wherein the agitation frequency is between 20 kHz and 100 kHz.   21. The method of claim 20, wherein the agitation frequency is between 25 kHz and 50 kHz.   The method of claim 8, wherein the agitation level is quantified by agitation power.   23. The method of claim 22, wherein the agitation power is between 1 W / gallon and 100 W / gallon.   24. The method of claim 23, wherein the agitation power is between 2 W / gallon and 50 W / gallon.   25. The method of claim 24, wherein the agitation power is between 5 W / gallon and 40 W / gallon.   26. The method of claim 25, wherein the agitation power is between 10 W / gallon and 30 W / gallon.   27. The method of claim 26, wherein the agitation power is between 20 W / gallon and 30 W / gallon.   28. The method of claim 27, wherein the stirring power is about 25 W / gallon.   The method of claim 1, wherein the predetermined time is at least 5 hours and at most 48 hours.   The method of claim 1, wherein the molybdenum mask has a set of through holes.   The method of claim 1, wherein the set of metals comprises chromium, copper, gold, and a lead / tin mixture. A method for cleaning a mask,
Placing a mask in the cleaning solution;
Agitating the cleaning solution for a predetermined time at a predetermined agitation level;
A method comprising: Further comprising the step of placing the mask in a container;
34. The method of claim 32, wherein placing the mask in the cleaning solution comprises placing the container in the cleaning solution.   34. The method of claim 33, further comprising closing the container.   35. The method of claim 34, further comprising receiving a mask.   The method of claim 32, wherein the mask is a molybdenum mask.   The method of claim 32, wherein the cleaning solution is a hydrochloric acid solution. A cleaning solution is contained in the first container;
A first container is contained in a second container;
38. The method of claim 37, wherein the second container further contains an aqueous solution surrounding the first container.   40. The method of claim 38, further comprising covering the first container with a lid.   38. The method of claim 37, further comprising drying the mask with nitrogen.   41. The method of claim 40, further comprising the step of cleaning the mask with deionized water.   38. The method of claim 37, wherein the cleaning solution is a hydrochloric acid solution having an acid concentration of at least 5%.   43. The method of claim 42, wherein the cleaning solution is a hydrochloric acid solution having an acid concentration of at least 15%.   44. The method of claim 43, wherein the cleaning solution is a hydrochloric acid solution having an acid concentration that is at least 25% and at most 50%.   45. The method of claim 44, wherein the cleaning solution is a hydrochloric acid solution having an acid concentration of about 37%.   38. The method of claim 37, wherein the predetermined time is at least 5 minutes and at most 300 minutes.   47. The method of claim 46, wherein the predetermined time is at least 10 minutes and at most 100 minutes.   48. The method of claim 47, wherein the predetermined time is at least 15 minutes and at most 40 minutes.   49. The method of claim 48, wherein the predetermined time is at least 25 minutes and at most 30 minutes.   47. The method of claim 46, wherein the predetermined time is at least 10 minutes and at most 100 minutes.   38. The method of claim 37, wherein the agitation level is quantified by agitation frequency.   52. The method of claim 51, wherein the agitation frequency is between 18 kHz and 2 MHz.   53. The method of claim 52, wherein the agitation frequency is between 20 kHz and 1 MHz.   54. The method of claim 53, wherein the agitation frequency is between 20 kHz and 100 kHz.   55. The method of claim 54, wherein the agitation frequency is between 25 kHz and 50 kHz.   56. The method of claim 55, wherein the agitation frequency is between 25 kHz and 40 kHz.   38. The method of claim 37, wherein the agitation level is quantified by agitation power.   58. The method of claim 57, wherein the agitation power is between 1 W / gallon and 100 W / gallon.   59. The method of claim 58, wherein the agitation power is between 2 W / gallon and 50 W / gallon.   60. The method of claim 59, wherein the agitation power is between 5 W / gallon and 40 W / gallon.   61. The method of claim 60, wherein the agitation power is between 10 W / gallon and 30 W / gallon.   62. The method of claim 61, wherein the agitation power is between 20 W / gallon and 30 W / gallon.   58. The method of claim 57, wherein the agitation power is about 25 W / gallon.   38. The method of claim 37, wherein the container is manufactured from Teflon (R).   38. The method of claim 37, wherein the container is made from a material that is essentially inert to hydrochloric acid.   38. The method of claim 37, wherein the container is made from high density polyethylene.   38. The method of claim 37, wherein the method is performed in an environment having a temperature that exists between 20 <0> C and 70 <0> C.   68. The method of claim 67, wherein the method is performed in an environment having a temperature that exists between 20 <0> C and 50 <0> C.   69. The method of claim 68, wherein the method is performed in an environment having a temperature that exists between 25 <0> C and 40 <0> C.   69. The method of claim 68, wherein the method is performed in an environment having a temperature of about 25 ° C.   69. The method of claim 68, wherein the method is performed in an environment having a temperature of about 30 degrees Celsius.   69. The method of claim 68, wherein the method is performed in an environment having a temperature of about 40 degrees Celsius. A method for cleaning a mask,
Putting the mask into the container;
Placing the container in a cleaning solution; and
A cleaning solution is contained in the first container;
A first container is contained in a second container;
The method wherein the second container further contains an aqueous solution surrounding the first container.   75. The method of claim 73, further comprising closing the container.   75. The method of claim 74, further comprising covering the first container with a lid.   76. The method of claim 75, further comprising the step of cleaning the mask with deionized water.   77. The method of claim 76, further comprising the step of drying the mask with nitrogen.   78. The method of claim 77, further comprising receiving a mask.   74. The method of claim 73, wherein the cleaning solution is a hydrochloric acid solution.   80. The method of claim 79, wherein the mask is a molybdenum mask.   76. The method of claim 75, further comprising agitating the cleaning solution. An apparatus for cleaning a mask,
A first container having an open top;
A second container having an open top, wherein the second container contains the first container;
A stirrer present in the second container;
A device comprising: An aqueous solution present in the second container;
A cleaning solution present in the first container;
The apparatus of claim 82, further comprising:   84. The apparatus of claim 83, further comprising a lid sized to cover the open top of the first container.   84. The apparatus of claim 83, further comprising a relatively inert container dimensioned to hold a plurality of masks and dimensioned to fit snugly within the first container.   The apparatus of claim 85, wherein the container has the form of a clamshell.   86. The apparatus of claim 85, wherein the container comprises a container container comprising an open top and a container lid having a dimension that covers the open top of the container container.   84. The apparatus of claim 83, wherein the cleaning solution is an acid.   90. The apparatus of claim 88, wherein the cleaning solution is hydrochloric acid.   84. The apparatus of claim 83, wherein the cleaning solution is a base.   The apparatus of claim 90, wherein the cleaning solution is sodium hydroxide. An apparatus for cleaning a mask,
A first means for cleaning the mask;
A second means for holding the mask;
A third means for stirring the first means and the second means;
A fourth means for accommodating the first means;
A fifth means for enclosing the fourth means;
Sixth means for holding the fifth means and the third means;
A device comprising: A method of cleaning a molybdenum mask having a series of metals deposited thereon,
Placing the molybdenum mask in a cleaning solution;
Removing the molybdenum mask from the cleaning solution after a predetermined time;
A method comprising:   94. The method of claim 93, further comprising agitating the cleaning solution for a predetermined amount of time at a predetermined agitation level. Further comprising the step of placing the molybdenum mask into the container;
95. The method of claim 94, wherein placing the molybdenum mask in the cleaning solution comprises placing a container in the cleaning solution.   96. The method of claim 95, further comprising closing the container.   99. The method of claim 96, further comprising receiving a mask.   94. The method of claim 93, wherein the cleaning solution is a hydrochloric acid solution. A cleaning solution is contained in the first container;
A first container is contained in a second container;
The second container further contains an aqueous solution surrounding the first container;
99. The method of claim 98.   100. The method of claim 99, further comprising covering the first container with a lid.   101. The method of claim 100, further comprising drying the mask with nitrogen.   102. The method of claim 101, further comprising the step of cleaning the mask with deionized water.   99. The method of claim 98, wherein the cleaning solution is a hydrochloric acid solution having an acid concentration of at least 5%.   94. The method of claim 93, wherein the set of metals comprises chromium, copper, gold, and a lead / tin mixture. A method for cleaning a molybdenum mask having a series of metals including chromium, copper, gold, and a lead / tin mixture deposited thereon,
Placing the molybdenum mask in a cleaning solution;
Removing the molybdenum mask from the cleaning solution after a predetermined time;
A method comprising:   106. The method of claim 105, further comprising agitating the cleaning solution for a predetermined amount of time at a predetermined agitation level. Further comprising the step of placing the molybdenum mask into the container;
107. The method of claim 106, wherein placing the molybdenum mask in the cleaning solution comprises placing a container in the cleaning solution.   108. The method of claim 107, further comprising receiving a mask.   106. The method of claim 105, wherein the cleaning solution is a hydrochloric acid solution. A cleaning solution is contained in the first container;
A first container is contained in a second container;
110. The method of claim 109, wherein the second container further contains an aqueous solution surrounding the first container.   111. The method of claim 110, further comprising covering the first container with a lid.   112. The method of claim 111, further comprising drying the mask with nitrogen.   113. The method of claim 112, further comprising the step of cleaning the mask with deionized water.   106. The method of claim 105, wherein the cleaning solution is a hydrochloric acid solution having an acid concentration of at least 5%.   114. The method of claim 113, wherein the cleaning solution is a hydrochloric acid solution having an acid concentration of at least 5%.

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