Abstract:
A host and ancillary tool interface methodology for distributed processing is described. The host tool manages a process, except for the generation of a product used in the process. To generate the product, the host tool provides an indication to an ancillary tool that the product is to be generated, and the ancillary tool generates the product after detection of the indication with no further intervention by the host tool. To provide the indication, the host tool preferably activates a control line whose voltage is monitored by the ancillary tool, or alternatively, sets one or more bits in a memory which is periodically checked by the ancillary tool.

Description:
FIELD OF THE INVENTION 
   The present invention generally relates to computer interface techniques and in particular, to a host and ancillary tool interface methodology for distributed processing. 
   BACKGROUND OF THE INVENTION 
   In the prior art system of  FIG. 1 , a host tool  10  includes a processor  11  managing a semiconductor process performed in a process chamber  30  on a semiconductor wafer  31  according to a process recipe stored in memory  12 . Although shown as separate items in the figure, the process chamber  30  is commonly integrated with or in the host tool  10 . Material sources  53  and  54  provide materials directly to the process chamber  30 . For these materials, the processor  11  causes main flow control valves  73  and  74  respectively in flow lines  63  and  64  to open by activating control lines  83  and  84  with appropriate signals through input/output (I/O) ports  16  and  17  at the appropriate times according to the process recipe. Precursor material sources  51  and  52 , on the other hand, provide precursor materials to a radio frequency (RF) inductively coupled plasma (ICP) torch  21  of an ancillary tool  20 . For these precursor materials, the processor  11  causes main flow control valves  71  and  72  in flow lines  61  and  62  to be opened by activating control lines  81  and  82  with appropriate signals through input/output (I/O) ports  14  and  15  at the appropriate times according to the process recipe, while providing controls through bus  40  to the ancillary tool  20  so that the RF ICP torch  21  generates a product such as a chemical species from the precursor materials and provides the product to the process chamber  30  through flow line  90  for processing the semiconductor wafer  31 . 
   In addition to managing the processing of the semiconductor wafer  31 , the host tool  10  may have other important tasks to perform. Therefore, it is useful to distribute the semiconductor processing so that the ancillary tool  20  generates the product and provides it to the process chamber  30  with minimal to no supervision from the host tool  10 , while at the same time, performing such function at the appropriate time according to the process recipe. When the ancillary tool  20  is manufactured and distributed by a different vendor than the host tool  10 , however, the two tools may be designed for different operating systems and/or communication protocols, thus complicating the task of interfacing the two tools with each other. 
   OBJECTS AND SUMMARY OF THE INVENTION 
   Accordingly, it is an object of the present invention to provide a host and ancillary tool interface methodology for distributed processing. 
   Another object is to provide a host and ancillary tool interface methodology that requires minimal host tool supervision of the ancillary tool&#39;s generation of a product. 
   Another object is to provide a host and ancillary tool interface methodology that provides ancillary tool generation of a product in a transparent manner to the host tool. 
   Still another object is to provide a host and ancillary tool interface methodology that does not require host and ancillary tools to have the same operating system or communication protocol. 
   These and additional objects are accomplished by the various aspects of the present invention, wherein briefly stated, one aspect is a method for interfacing host and ancillary tools, comprising: activating a control line of a host tool when a product is to be provided; and generating and providing the product when activation of the control line is detected by an ancillary tool. 
   Another aspect is an apparatus for generating and providing a product as part of a process, comprising: a host tool configured to manage a process and activate a control line when a product is to be provided as part of the process; and an ancillary tool configured to generate and provide the product when activation of the control line is detected. 
   Another aspect is an apparatus for generating and providing a product as part of a process, comprising an ancillary tool configured to generate a product when the ancillary tool detects activation of a control line activated by a host tool configured to activate the control line when the product is to be provided as part of a process managed by the host tool. 
   Another aspect is a system for semiconductor processing, comprising: a process chamber for housing at least one semiconductor wafer for semiconductor processing; a host tool configured to manage the semiconductor processing and activate a control line when a product is to be provided to the process chamber as part of the semiconductor processing; and an ancillary tool configured to generate and provide the product to the process chamber when activation of the control line is detected. 
   Still another aspect is an apparatus for generating a chemical species, comprising: a product generator unit; and a detection unit configured to detect an indication provided by a host tool to generate a product as part of a process being managed by the host tool, and to activate the product generator unit to generate the product upon detecting the indication. 
   Yet another aspect is a method for interfacing host and ancillary tools for distributed processing of a semiconductor wafer, comprising: providing an indication to an ancillary tool when a product is to be generated and provided to a process chamber for processing a semiconductor wafer as a part of a process recipe being executed by a host tool; and automatically causing a product generator in the ancillary tool to generate and provide the product to the process chamber without further intervention from the host tool upon detecting the indication. 
   Additional objects, features and advantages of the various aspects of the present invention will become apparent from the following description of its preferred embodiment, which description should be taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a block diagram of a prior art semiconductor processing system. 
       FIG. 2  illustrates a block diagram of a first embodiment of a semiconductor processing system utilizing aspects of the present invention. 
       FIG. 3  illustrates a block diagram of a second embodiment of a semiconductor processing system utilizing aspects of the present invention. 
       FIG. 4  is a diagrammatic view of a chemical generator incorporating aspects of the invention. 
       FIG. 5  is a cross-sectional view taken along line  402 - 402  of  FIG. 4 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   In  FIGS. 1˜3 , items in the figures that are identified by the same reference number are functionally equivalent and similarly constructed. 
     FIG. 2  illustrates, as an example, a block diagram of a first and preferred embodiment of a semiconductor processing system. The application in this case is similar to that described in reference to  FIG. 1 , in that a host tool  210  includes a processor  11  managing a semiconductor process performed in a process chamber  30  on a semiconductor wafer  31  according to a process recipe stored in memory  212 . Although shown as separate items in the figures to simplify illustration of material flows, the process chamber  30  is preferably integrated with or in the host tool  210 . 
   The process recipe in this case, however, is a modified version of that described in reference to  FIG. 1 , because the processor  11  of the host tool  210  in this case does not control the generation of a product which is to be generated by an ancillary tool  220  and provided to the process chamber  30  as part of the process. Therefore, that portion of the process recipe has been deleted in the modified version of the process recipe, and the deleted portion (i.e., the “product recipe”) has instead been stored in a memory  202  of the ancillary tool  220  for execution by its processor  201 . Thus, although the timing of when the product is generated and provided to the process chamber  30  is still controlled by the processor  11  of the host tool  210  in accordance with the process recipe stored in its memory  212 , the actual generation and providing of the product to the process chamber  30  by the ancillary tool  220  is done transparently to the host tool  210 . 
   When it is time to provide the product to the process chamber  30  as part of the process according to the process recipe stored in memory  212 , the host tool  210  provides an indication to the ancillary tool  230  that the product is to be generated. The processor  11  provides the indication in this case by activating control line  81  with an appropriate signal passed through input/output (I/O) port  14 . Thus, it appears from the process recipe that the product is being provided just like any other material from a material source, such as material sources  53  and  54 , directly to the process chamber  30  for processing the semiconductor wafer  31 . 
   A detection circuit  203  in the ancillary tool  220  monitors the control line  81  and detects the indication that the product is to be generated by, for example, detecting a voltage magnitude such as 24.0 volts on the control line  81 . Upon such detection, the detection circuit  203  then notifies the processor  201  so that it causes the RF ICP torch  21  to generate the product according to the product recipe stored in memory  202  and consequently, provide the product to the process chamber  30  through flow line  90 . 
   In order to generate the product according to the product recipe, the processor  201  causes main flow control valves  71  and  72  in flow lines  61  and  62  to be opened by activating control lines  281  and  282  with appropriate signals at the appropriate times according to the product recipe so that precursor materials respectively from precursor material sources  51  and  52  are provided directly to the RF ICP torch  21 . 
   The product in this case is a chemical species formed from the precursor materials provided by precursor material sources  51  and  52 . Additional details in the generation of such chemical species using an RF ICP torch such the RF ICP torch  21  are included in commonly owned, U.S. patent application Ser. No. 10/404,216 entitled “Remote ICP Torch for Semiconductor Processing,” filed Mar. 31, 2003, which is incorporated herein by this reference. 
   Also to support the process recipe, material sources  53  and  54  provide materials directly to the process chamber  30  as the processor  11  causes main flow control valves  73  and  74  respectively in flow lines  63  and  64  to open by activating control lines  83  and  84  with appropriate signals through input/output (I/O) ports  16  and  17  at the appropriate times according to the process recipe. 
   Although this example depicts two precursor material sources,  51  and  52 , and two material sources,  53  and  54 , being used, it is to be appreciated that the number of such sources as well as the types of materials that they provide depends upon and varies with the process and product recipes being followed for the semiconductor processing. 
     FIG. 3  illustrates a block diagram of a second and embodiment of a semiconductor processing system. The application in this case is also similar to that described in reference to  FIG. 1  in that a host tool  310  includes a processor  11  managing a semiconductor process performed in a process chamber  30  on a semiconductor wafer  31  according to a process recipe stored in memory  312 . Although shown as separate items in the figures to simplify illustration of material flows, the process chamber  30  is preferably integrated with or in the host tool  310 . 
   The process recipe in this case, is also a modified version of that described in reference to  FIG. 1 , because the processor  11  in this case also does not control the generation of a product by an ancillary tool  320 . In this example, however, the host tool  310  provides a different type of indication to the ancillary tool  320  to generate the product. 
   The indication to generate the product in this case involves either the setting of one or more bits in a memory  302  of the ancillary tool  320  in a similar fashion as conventionally done to set bits in an interrupt flag field, or alternatively, the activation of an interrupt line coupled to the ancillary tool  320 . The ancillary tool  320  then detects the indication as it would a conventional interrupt provided in an interrupt flag field or on an interrupt line, and then generates and provides the product to the process chamber  30  upon detection of the indication. 
   The product and its generation in this example is the same as described in reference to  FIG. 2 . Also, the use of precursor materials respectively from the precursor material sources  51  and  52  for the product recipe, and the use of materials respectively from the material sources  53  and  54  for the process recipe are the same as described in reference to  FIG. 2 . 
     FIG. 4  is a diagrammatic view of a chemical generator incorporating aspects of the invention.  FIG. 5  is a cross-sectional view taken along line  402 - 402  of  FIG. 4 . As illustrated in  FIG. 4 , a chemical generator includes a free radical source  411  which has one or more chambers in which free radicals are created and delivered for recombination into stable species. In the embodiment illustrated, the source has three chambers which are formed by elongated, concentric tubes  412 - 414 . Those chambers include a first annular chamber  416  between the outermost tube  412  and the middle tube  413 , a second annular chamber  417  between middle tube  413  and the innermost tube  414 , and a third chamber  418  inside the innermost tube  414 . The tubes are fabricated of a material such as ceramic or quartz. 
   The number of tubes which are required in the generator is dependent upon the chemical species being generated and the reaction by which it is formed, with a separate chamber usually, but not necessarily, being provided for each type of free radical to be used in the process. 
   Gases or other precursor compounds from which the free radicals are formed are introduced into the chambers from sources  421 - 423  or by other suitable means. Such precursors can be in gaseous, liquid and/or solid form, or a combination thereof. 
   As previously explained, although a separate chamber may be used for providing each type of free radicals, it is also contemplated for certain chemical reactions such as described below that a single chamber may also be used for providing more than one type of free radicals. In such a case, gases or other precursor compounds from which the more than one type of free radicals are formed are introduced into the single chamber from corresponding sources. 
   A plasma is formed within the one or more chambers to create the free radicals, and in the embodiment illustrated, the means for generating the plasma includes an induction coil  426  disposed concentrically about the one or more tubes, a radio frequency (RF) power generator  427  connected to the coil by a matching network  428 , and a Tesla coil  429  for striking an arc to ignite the plasma. The plasma can, however, be formed by any other suitable means such as RF electrodes or microwaves. 
   In the embodiment illustrated, the free radicals are recombined to form the desired species downstream of the tubes. In this case, recombination takes place in a chamber  431  which is part of a reactor  432  in which a semiconductor wafer  433  is being processed. Recombination can be promoted by any suitable means such as by cooling  436  and/or by the use of a catalyst  437 . 
   Cooling can be effected in a number of ways, including the circulation of a coolant such as an inert gas, liquid nitrogen, liquid helium or cooled water through tubes or other suitable means in heat exchange relationship with the reacting gases. 
   A catalyst can be placed either in the cooling zone or downstream of it. It can, for example, be in the form of a thin film deposited on the wall of a chamber or tube through which the reacting gases pass, a gauze placed in the stream of gas, or a packed bed. The important thing is that the catalyst is situated in such a way that all of the gas is able to contact its surface and react with it. 
   If desired, monitoring equipment such as an optical emission spectrometer can be provided for monitoring parameters such as species profile and steam generation. 
   Although the various aspects of the present invention have been described with respect to a preferred embodiment, it will be understood that the invention is entitled to full protection within the full scope of the appended claims.