Abstract:
In a first aspect, a method for cleaning a semiconductor fabrication chamber component having an orifice is provided. The method includes (A) placing the component into a bath having a cleaning solution; (B) flowing a fluid into the orifice thereby maintaining at least a first portion of the orifice free from cleaning solution while the cleaning solution cleans the component; and (C) withdrawing the fluid from the orifice such that cleaning solution enters into the first portion of the orifice and cleans the first portion of the orifice. Numerous other aspects are also provided.

Description:
[0001]    The present application claims priority to U.S. Provisional Patent Application Ser. No. 60/863,906, filed Nov. 1, 2006, which is hereby incorporated by reference herein in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to semiconductor device manufacturing, and more particularly to methods and apparatus for cleaning components of a chamber used during semiconductor device manufacturing. 
       BACKGROUND OF THE INVENTION 
       [0003]    A gas distribution system of a deposition chamber may include a face plate, gas distribution plate or another gas distribution element having one or more holes, openings and/or other orifices through which gases are flowed during semiconductor device processing. During deposition processes performed within the chamber, the orifices and other surfaces of a gas distribution element may become coated with material, such as deposition species, deposition by-products, etc., of the deposition process. 
         [0004]    To ensure proper operation of the deposition chamber and the gas distribution element, the gas distribution element may be periodically cleaned to remove any deposited material from the various surfaces and/or orifices of the gas distribution element. For example, the gas distribution element may be placed in cleaning solution, such as an acid bath, which etches any deposited material from the orifices and other surfaces of the gas distribution element. However, such a cleaning process may damage the gas distribution element and limit its useful lifetime. Accordingly, a need exits for improved methods for cleaning components of a chamber, such as a gas distribution element. 
       SUMMARY OF THE INVENTION 
       [0005]    In a first aspect of the present invention, a first method of cleaning a semiconductor fabrication chamber component having an orifice is provided. The method includes (A) placing the component into a bath having a cleaning solution; (B) flowing a fluid into the orifice thereby maintaining at least a first portion of the orifice free from cleaning solution while the cleaning solution cleans the component; and (C) withdrawing the fluid from the orifice such that cleaning solution enters into the first portion of the orifice and cleans the first portion of the orifice. 
         [0006]    In a second aspect of the present invention, a method of cleaning a semiconductor fabrication chamber component having an orifice is provided. The method comprises (A) placing the component into a bath having a cleaning solution; (B) flowing a fluid into the orifice thereby maintaining at least a first portion of the orifice free from cleaning solution while the cleaning solution cleans a second portion of the orifice; and (C) withdrawing the fluid from the orifice such that cleaning solution enters into the first portion of the orifice and cleans the first portion of the orifice. 
         [0007]    In a third aspect of the present invention, an apparatus for use during cleaning of a semiconductor device manufacturing component is provided. The apparatus includes (A) a jig having a surface adapted to couple to and form a fluid tight seal with the component; and (B) at least one inlet adapted to deliver a fluid to the component and apply a vacuum to the component during cleaning of the component with a cleaning solution. 
         [0008]    Other features and aspects of the present invention will become more fully apparent from the following detailed description, the appended claims and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0009]      FIG. 1A  is a side view of a chamber component, such as a face plate or other gas distribution element, having an orifice. 
           [0010]      FIG. 1B  is an exploded view of an exemplary embodiment of the orifice of  FIG. 1A . 
           [0011]      FIG. 2  is a side view of a component placed within a bath, in accordance with the invention. 
           [0012]      FIG. 3  is a side elevational view of an exemplary embodiment of an orifice of the component of  FIG. 2 . 
           [0013]      FIG. 4  illustrates a process of forming a cleaning solution in accordance with the present invention. 
           [0014]      FIG. 5  is a flowchart illustrating a process for cleaning a component in accordance with an embodiment of the present invention. 
           [0015]      FIG. 6  shows a cleaning solution within a first, narrow portion of an orifice at a point that indicates a top level of a cleaning solution within a bath. 
           [0016]      FIG. 7  illustrates a process for cleaning a component of a processing chamber in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    The present invention provides methods and apparatus for cleaning components of a chamber used during semiconductor device manufacturing. In particular, methods and apparatus are provided that allow chamber components to be cleaned while protecting small geometries of the components that may be damaged by the cleaning process. 
         [0018]    In addition, the present invention provides a method of preparing a cleaning solution and using the cleaning solution. The cleaning solution has a cleaning agent, such as an etchant, which removes residue from a component such as a gas distribution element. The cleaning solution may also have a passivator which interacts with the component being cleaned, such as to reduce corrosion of the component. 
         [0019]    As stated, a gas distribution system of a deposition chamber may include a face plate, gas distribution plate or other gas distribution element having one or more holes, openings or other orifices through which gases are flowed during semiconductor device processing. During deposition processes performed within the chamber, the orifices and other surfaces of a gas distribution element may become coated with material, such as deposition species, deposition by-products, etc., of the deposition process. 
         [0020]    To ensure proper operation of the deposition chamber and the gas distribution element, the gas distribution element may be periodically cleaned to remove any deposited material from the gas distribution element. Typically, the gas distribution element is placed in cleaning solution, such as an acid bath, which etches any deposited material from the orifices and other surfaces of the gas distribution element. However, use of such an acid bath may over etch and/or damage the orifices and/or other small geometry features of the gas distribution element, as the large planar surfaces of the gas distribution element may have relatively thick deposited layers that take longer to remove than the layers formed within the orifices and/or on other small geometry features of the gas distribution element. Such aggressive cleaning of small geometry features of the gas distribution element limits the useful lifetime of the gas distribution element. 
         [0021]    Methods and apparatus of the present invention allow cleaning of chamber components, such as gas distribution elements, while protecting small geometries of the components that may be damaged by the cleaning process. For example, in some embodiments of the invention, a gas distribution element may include a major surface (e.g., which faces a substrate during processing) having one or more orifices formed within the major surface and that extend through the gas distribution element. To clean the major surface of the gas distribution element while protecting the orifice(s), the major surface may be placed in a cleaning solution while a gas is fed into the orifice(s). The gas fed into the orifice(s) prevents cleaning solution from entering the orifice(s), or limits entry of cleaning solution into the orifice(s), while the major surface is cleaned. 
         [0022]    After the major surface of the gas distribution element has been cleaned, the orifice(s) may be cleaned by reducing or eliminating the gas flow to the orifice(s) so as to allow the cleaning solution to enter the orifice(s). In some embodiments, a vacuum may be employed to draw cleaning solution through the orifice(s). 
         [0023]    In this manner, large, relatively etch-insensitive features such as the major surfaces of the gas distribution element may be cleaned during a first phase of cleaning, and small, relatively etch-sensitive features, such as holes or other orifices of the gas distribution element may be cleaned during a more controlled, second phase of cleaning. These and other embodiments of the invention may be employed to clean other chamber components. Exemplary embodiments of the invention are now described below with reference to  FIGS. 1A-7 . 
         [0024]      FIG. 1A  is a side view of a chamber component  100 , such as a face plate or other gas distribution element, having an orifice  102  (e.g., a hole or otherwise shaped opening that extends through the component  100 ). Although not shown, the component  100  may also include additional orifices similar to the orifice  102 . The component  100  may be used, for example, during a chemical vapor deposition or similar process where a gas passes through the component  100  and reacts and/or deposits onto a substrate (not shown), such as a semiconductor wafer. During use, the component  100  is exposed to deposition species, deposition by-products and the like (e.g., aluminum fluoride and silicon fluoride). As a result, residue from both deposition species and by-products may accumulate within the orifice  102  and on a front face  104  of the component  100 . When residue builds up in the orifice  102 , the flow rate of a gas through the orifice  102  may be adversely affected. More specifically, the flow rate may decrease, which may adversely affect deposition within the deposition chamber, such that the component  100  may become unreliable and/or unusable during deposition operations. 
         [0025]    The component  100  may be cleaned to remove residue from the orifice  102  and the face  104  of the component  100 . Typically, the component  100  is placed in a bath having a cleaning solution  106  which includes an etchant (e.g., an acid which breaks down the residue). The etchant etches residue from both the orifice  102  and the face  104 . However, the etchant may erode the component  100  such that the dimensions of the orifice  102  change, eventually rendering the component  100  unusable. 
         [0026]      FIG. 1B  is an exploded view of an exemplary embodiment of the orifice  102  of  FIG. 1A . Other orifice shapes and/or sizes may be used. The orifice  102  includes a narrow portion  102   a  having a width X 1  and a length Y 1 . 
         [0027]    During cleaning, the cleaning solution may etch the orifice  102  such that the orifice becomes wider and/or shorter. For example, the width X 1  of the portion  102   a  may increase to a width X 2  as a result of the etchant corroding the portion  102   a . Furthermore, the length Y 1  of the portion  102   a  may decrease to a length Y 2 . 
         [0028]    The flow characteristics of the orifice  102  may be affected due to the changed width and/or height of the orifice  102 , thereby affecting the deposition capabilities of the component  100 . Furthermore, although not shown, the component  100  may include a number of orifices. In some instances, the cleaning solution may unevenly erode the orifices such that after cleaning, the orifices have different widths and/or lengths. In instances where the component  100  has orifices with different dimensions, the component will not uniformly distribute a gas over a substrate. Thus, deposition layers may be uneven and potentially out of tolerance. 
         [0029]    In accordance with the present invention, a method of uniformly cleaning a component is provided where contact between a portion of an orifice and a cleaning solution may be minimized during cleaning of the component.  FIG. 2  is a side view of the component  100  placed within a bath  204 , in accordance with the invention. The bath  204  comprises a cleaning solution which removes residue from the component  100 . As will be discussed in greater detail with reference to  FIG. 4 , the cleaning solution in the bath  204  may be formed in accordance with the cleaning requirements of the component  100 . 
         [0030]    With reference to  FIG. 2 , the component  100  is attached to a jig  206  which has a passage  210  configured to allow the flow of a fluid  208  into the jig  206 . In one embodiment, the jig  206  may be hollow and configured such that the component  100  has a fluid tight fit with the jig  206  when the component  100  is placed on the jig  206  (e.g., via one or more o-rings or other seals (not shown)). Furthermore, the jig  206  is configured such that the jig  206  may hold a pressure at an upper surface of the component  100 . The jig  206  may be constructed, for example, from a material which is non-reactive with an acid or other etchant, such as polyethylene or the like. 
         [0031]      FIG. 3  is a side elevational view of an exemplary embodiment of the orifice  102  of the component  100 . The orifice  102  includes a first, narrow portion  302 , a second portion  304 , and a third portion  305 . The first, narrow portion  302  has a width X 1  and a length Y 1  that, to a large extent, dictate the flow characteristics of a gas through the component  100 . In one embodiment of the present invention, the width X 1  is in a range of about 12 microns to about 20 microns and preferably is about 16 microns. However, the width X 1  of the first, narrow portion  302  may vary according to the application of the component  100 . For example, applications requiring high flow rates of gases from the component  100  may have wider orifices. Alternatively, applications requiring lower flow rates may have narrower orifices. 
         [0032]    In one embodiment, the length Y 1  is in a range of about 40 mils to about 45 mils and is preferably about 43 mils. It should be noted that the length of the first, narrow portion  302  may vary according to the application of the component  100 . To further illustrate, applications requiring a higher flow rate may have a shorter length. On the other hand, applications requiring a lower flow rate may have a longer length. For example, both the length of the first, narrow portion  302  and the width of the first, narrow portion  302  may be determined according to the following ratio: flow rate=(12.1*(X 1 ) 3 )/Y 1 . 
         [0033]    As will be described further below, in at least one embodiment, the first narrow portion  302  of the component  100  is protected as the front face  104  of the component  100  is cleaned with the cleaning solution in the bath  204 . As such, the first, narrow portion  302  is not damaged during cleaning of the component  100 . For example, the component  100  may be coupled to the jig  206 . Then, to clean the front face  104  of the component  100  while protecting the first, narrow portion  302  of the orifice  102 , the front face  104  may be placed in the cleaning solution of the bath  204  while a fluid (e.g., gas) is fed into the first, narrow portion  302  of the component  100  via the passage  210  of the jig  206 . After the front face  104  is cleaned, fluid flow to the first narrow portion  302  of the orifice  102  may be halted so as to allow cleaning solution to enter and clean the first, narrow portion  302 . For example, a vacuum may be applied to the first, narrow portion  302  via the passage  210  of the jig  206  so as to draw cleaning solution into the first, narrow portion  302  of the orifice  102  (as described further below). 
         [0034]      FIG. 4  illustrates a process  400  of forming a cleaning solution in accordance with the present invention. With reference to  FIG. 4 , in a step  402 , the cleaning requirements of a component, such as the component  100  are determined. For example, the amount of residue to be removed from the component  100  may be determined. Based on the cleaning requirements of the component  100 , a cleaning solution may be formed (in the step  404 ). 
         [0035]    As an example, one part of the cleaning solution may be an etchant (e.g. hydrofluoric acid (HF) or anything capable of removing residue) and a second part of the cleaning solution may be a passivator (e.g., nitric acid (HNO 3 ) or anything which prevents corrosion). In accordance with one embodiment of the present invention, a cleaning solution may be formed with about 10% HF and about 90% HNO 3 . However, the amount of etchant used and the amount of passivator used in the cleaning solution may vary depending on the etching requirements for the component being cleaned. To further illustrate, if greater etching is required, the cleaning solution may include about 15% HF and about 85% HNO 3 . If less etching is required, then a cleaning solution having about 5% HF and about 95% HNO 3  may be used. Other ratios of etchant to passivator and/or other cleaning solution chemistries may be used. After formation, the cleaning solution is placed in a bath in a step  406 , such as the bath  204 , for cleaning of a component, such as the component  100 . 
         [0036]      FIG. 5  is a flowchart illustrating a process  500  for cleaning a component in accordance with an embodiment of the present invention. In a step  502 , a chamber component having an orifice is inserted into a cleaning solution. For example, making reference to  FIG. 2 , the component  100 , having the orifice  102 , is inserted into the bath  204  having a cleaning solution. Once the component  100  is placed in the cleaning solution, the component  100  is cleaned in a step  504 . 
         [0037]    In the step  504 , at least a first portion of the orifice is maintained free of a cleaning solution while the component is cleaned. For example, as shown in  FIG. 3 , the first, narrow portion  302  of the orifice  102  may be maintained free of cleaning solution (as shown by the upper boundary  204   a  of the cleaning solution). In accordance with an embodiment of the present invention, a portion (or all) of an orifice of a component is maintained free of the cleaning solution by injecting a gas (e.g., air, oxygen, nitrogen, argon, xenon, or any other suitable gas) into the orifice during cleaning of the component. For example, making reference again to  FIG. 2 , when the component  100  is placed in the bath  204 , a gas may be injected into the jig  206  through the passage  210 . The gas may be injected into the component  100  at a pressure which prevents cleaning solution from entering into the first, narrow portion  302  ( FIG. 3 ) of the orifice  102 . In some embodiments, the gas may be injected at a pressure of about 1.1 atmospheres to about 1.5 atmospheres, although other pressures may be used. 
         [0038]    With reference to  FIG. 3 , when the gas is injected into the jig  206  via the passage  210 , the gas flows into the first, narrow portion  302  of the orifice  102 . As the gas flows into the first, narrow portion  302 , the cleaning solution  204  is maintained below an end  302   a  of the first, narrow portion  302  of the orifice  102 . The cleaning solution may be maintained at any other desired level, and may be excluded entirely from the orifice  102  by adjusting the pressure within the jig  206 . 
         [0039]    As previously mentioned, the dimensions X 1  and Y 1  of the first, narrow portion  302  of the orifice may be important to the functionality of the component  100 . The end  302   a  is the end point of the first, narrow portion  302 . Thus, if the cleaning solution rises above the end  302   a  during cleaning of the face  104  of the component  100 , the cleaning solution may erode the first, narrow portion  302 , thereby altering the dimensions X 1  and Y 1 . 
         [0040]    In the embodiment shown in  FIG. 3 , the face  104  of the component  100  is cleaned along with second and third portions  304  and  305  of the orifice  102  with the cleaning solution of the bath  204 . In some embodiments, the time for cleaning the face  104  and/or the second and third portions  304  and  305  can be in a range from about ten minutes to about five hours. Other cleaning times may be used. It should be noted that if the first, narrow portion  302  is exposed to the cleaning solution for the same period of time (e.g., ten minutes to five hours), the first, narrow portion  302  may erode (e.g., unacceptably). In general, the duration of cleaning depends on the type and amount of residue which has accumulated on the component  100 . For example, if the component  100  has been used in processes which have resulted in the build-up of carbon on the component  100 , cleaning may last up to five hours. 
         [0041]    In a step  506 , the first portion of the orifice of the component is cleaned. For example, gas flow to the orifice may be stopped to allow cleaning solution to enter the orifice. In at least one embodiment, a vacuum may be applied to the orifice. For example, in the embodiment of  FIG. 2 , a vacuum may be applied to the jig  206  that draws cleaning solution through the orifice  102  and out of the passage  210  of the jig  206 . In some embodiments, a vacuum in the range between about 250 mTorr and about 750 mTorr and more preferably about 500 mTorr may be applied to the jig  206  and/or the orifice  102 . When the vacuum is applied to the first, narrow portion  302  of the orifice  102 , the cleaning solution moves into the first, narrow portion  302  and cleans residue disposed therein. 
         [0042]    The first, narrow portion  302  of the orifice  102  may be, for example, continuously cleaned (e.g., the cleaning solution may be in continuous contact with the first portion of the orifice). In an alternative embodiment, the cleaning solution may be cycled into and out of the first portion of the orifice. In this embodiment, gas is repeatedly pumped into and out of the first portion (e.g., at regular intervals) such that the cleaning solution is drawn into and then out of the first, narrow portion  302  of the orifice  102 . When the gas is pumped into the first, narrow portion  302 , the gas forces the cleaning solution out of the first, narrow portion  302 . When the gas is pumped out of the first, narrow portion  302 , vacuum is again created and the cleaning solution moves back into the first, narrow portion  302  for cleaning of residue. In at least one embodiment, cleaning of the first portion of the orifice may be performed for about 5 minutes, although longer or shorter cleaning times may be used. 
         [0043]    To further illustrate,  FIG. 6  shows the cleaning solution within the first, narrow portion  302  of the orifice  102  at a point  204   a  that indicates a top level of the cleaning solution within the bath  204 . Initially, gas is pumped out of the first, narrow portion  302  of the orifice  102  to form a vacuum. When the gas is pumped out to form a vacuum, the cleaning solution moves into the first, narrow portion  302 . The cleaning solution may flow through the first, narrow portion  302  of the orifice  102 , or may be held within the first, narrow portion  302  for a suitable time period. 
         [0044]    Alternatively, gas may be pumped back into the first, narrow portion  302  of the orifice  102 , thereby forcing the cleaning solution out. After the cleaning solution is forced out of the first, narrow portion  302 , gas again may be pumped out of the orifice  102  so that cleaning solution from the bath  204  moves into the first, narrow portion  302  for further cleaning. This process may be repeated until the first portion is sufficiently clean. After the orifice is cleaned, the process  500  is complete. 
         [0045]      FIG. 7  illustrates a process  700  for cleaning a component of a processing chamber in accordance with an embodiment of the present invention. Initially, a component is removed from a process chamber in a step  702 . Once the component is removed from the process chamber, the component is inserted into a bath having a cleaning solution in a step  704 . When the component is inserted into the bath, the process  700  performs a step  706 . 
         [0046]    In the step  706 , a fluid (e.g., nitrogen or another gas such as an inert gas) is injected into a first portion of an orifice of the component. The fluid is injected to prevent the cleaning solution from entering the first portion of the orifice while a second portion of the orifice is cleaned. As such, the cleaning solution does not corrode the first portion of the orifice while the second portion of the orifice is cleaned in a step  708 . Therefore, the dimensions of the first portion are maintained during the cleaning process. 
         [0047]    During cleaning of the second portion of the orifice, the cleaning solution is maintained within the second portion of the orifice (step  710 ). For example, making reference again to  FIG. 3 , the fluid maintains the cleaning solution of the bath  204  below the point  302   a  of the first, narrow portion  302  of the orifice  102  during cleaning of the second portion  304 . Therefore, the first, narrow portion  302  remains free of the cleaning solution while the second portion  304  is cleaned. Once the second portion is cleaned, the process  700  performs step  712 . 
         [0048]    During the step  712 , a vacuum is formed in the first portion of the orifice. The vacuum is formed in the first portion of the orifice by pumping out the fluid in the orifice (which was supplied during step  708 ). In accordance with an embodiment of the present invention, a vacuum in a range between about 250 mTorr and about 750 mTorr and more preferably about 500 mTorr may be used. When the vacuum forms in the first portion of the orifice, cleaning solution enters the orifice and cleans the first portion (step  714 ). 
         [0049]    For example, making reference to  FIG. 6 , when a vacuum is formed in the first, narrow portion  302  of the orifice  102 , the cleaning solution in the bath  204  enters therein. As the cleaning solution enters the first, narrow portion  302 , the cleaning solution removes residue accumulated in the first, narrow portion  302 . In one embodiment, the cleaning solution remains in the first, narrow portion  302  of the orifice  102  for a period of about five minutes (although other cleaning times may be used). After the first portion of the orifice is cleaned, the component is removed from the solution in a step  716  and the process  700  is completed. 
         [0050]    The foregoing description discloses only exemplary embodiments of the invention. Modifications of the above disclosed apparatus and methods which fall within the scope of the invention will be readily apparent to those of ordinary skill in the art. For instance, the time in which a portion of an orifice is exposed to cleaning solution may vary depending upon the residue present therein. In addition, cleaning solutions having a variety of etchants and/or passivators may be used. As a result, the time of exposing an orifice may also depend on the cleaning solution that is used. 
         [0051]    Accordingly, while the present invention has been disclosed in connection with exemplary embodiments thereof, it should be understood that other embodiments may fall within the spirit and scope of the invention, as defined by the following claims.