Abstract:
The invention shows a workpiece template and a number of additional elements for forming wafers of varying thicknesses=. The template is formed of a main disk including a plurality of cavities extending through a main plate with either a frictionless material or a backing plate forming the cavity base. The template shows additional elements to aid in the lapping/polishing abrasive fluid movement in the form of spiraling channels moving across the top surface of the template. The channels can extend through the template cavity walls. Also shown are the improvement previously stated applied to a template having notched gear-like teeth for another type of lapping/polishing machine.

Description:
REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation-in-part application of United States patent applications: 
     a. Ser. No. 09/840,506 filed Apr. 23, 2001 and U.S. Pat. No. 6,612,095 
     b. Ser. No. 09/908,013 filed Jul. 18, 2001 and 
     c. Ser. No. 09/962,897 filed Sep. 25, 2001 U.S. Pat. No. 6,645,049 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to workpiece templates and, more specifically, to workpiece templates used in lapping and polishing silicon wafers in either single or double sided polishing machines. The present invention is a template having a plurality of cavities within the body of the surface for inserting objects such as silicon wafers intended for lapping and polishing to a thickness equal to the depth of the template cavity. 
     In addition, the thickness of the intended object can be varied by inserting one or more shims into the workpiece cavity. 
     2. Description of the Prior Art 
     There are templates for lapping and polishing wafers to a desirable thickness determined by the depth of the template cavity. It has been found by the inventor that they contain one or more undesirable characteristics that render them unsuitable for repeated use. 
     The process of lapping and polishing wafers on a single side involves placing the workpiece or workpieces into a template and placing the template upside down between a rotating pneumatic head and a table having a controlled flow of abrasive slurry flowing onto the table surface during the pneumatic head rotation whereby the wafer blanks will be honed and polished to the thickness of the template. 
     There are a number of undesirable side effects that can occur in the prior art. As the wafers approach the thickness of the template cavity, the amount of fluid between the template and the lapping/polishing surface decreases causing spotted changes in the surface temperature of the template burnishing the template. 
     Another undesirable effect of this method relates to the cross sectional thickness of the, finished wafer. The wafers can rotate within the cavity causing the wafers to continuously butt up against the wall of the cavity and rise from the cavity base whereby the edge thickness can vary from the center thickness. This is especially undesirable in applications where tolerances are measure in microns. 
     An object of the present invention is to overcome these shortcomings within the prior art. The present invention also addresses another shortcoming within the prior art relating to the inordinate number of templates used because of the varied thicknesses required within the end product. The present invention addresses this need through the use of shims which can have a thickness imprinted on the shim or can be classified using a color code to indicate thickness. These shims can be permanently fixed to the workpiece cavity base having indicia indicating the thickness of the end product or a color code scheme can be used to indicate the thickness of the end product. In addition one or more shims could be removably inserted into one or more cavities to vary the thickness of the finished end product. 
     In addition the present invention addresses another shortcoming within the prior art related to lapping and polishing of non-standard shapes such as triangles, squares, rectangles, etc. The present invention overcomes the need for creating full sized templates for the aforementioned non-standard shapes by having smaller templates having cavities conforming to the desired non-standard shapes that are of substantially equal diameter to the cavities of the larger templates, thereby enabling lapping and/or polishing of silicon wafers of a non-standard size which also provides for the lapping and polishing of mixed wafer shapes by the selection and placements of smaller templates having the preselected shape or shapes placed within one or more cavities of the larger workpiece template. 
     Another additional element is provided for by the present invention in the form of channels etched into the top surface of the workpiece template for the purpose of channeling the abrasive and/or polishing fluid across the surface of the workpiece template during a lapping and/or polishing operation. Again returning to the problem of workpiece template burnishing due in some part to the lack of fluid between the workpiece template and the lapping/polishing surface, the present invention channels the lapping/polishing fluid across the entire surface of the workpiece template. Furthermore, the channels also serve to reduce hydrodynamic forces between the template and lapping/polishing operational surface caused by the rotational speed of the head, the lapping/polishing surface and the fluid therebetween by limiting the planar surface area between points of fluid transition which is currently the peripheral edge of the template. 
     Basically, the channels provide an abundance of fluid across the non-channeled planar surface by providing channels where fluid can be transferred from or to depending on the dynamic fluid forces at any point on the non-channeled planar surface. 
     Therefore, because of the aforementioned problems and shortcomings of the prior art it is felt that a need exists for the present invention and while the prior art may be suitable for the purposes for which they were designed, they would not be as suitable for the purposes of the present invention, as hereinafter described. 
     SUMMARY OF THE PRESENT INVENTION 
     A primary object of the present invention is to provide a workpiece template for lapping and/or polishing silicon wafers. 
     Another object of the present invention is to provide a lapping/polishing workpiece template that can be repeatedly reused. 
     Yet another object of the present invention is to provide a lapping and polishing workpiece template having a main plate with at least one cavity therethrough for the placement of a workpiece, such as a silicon wafer, to be lapped and/or polished. 
     Still yet another object of the present invention is to provide a lapping/polishing workpiece template comprised of a main plate having a substantially smoothed edged circular configuration. 
     A further object of the present invention is to provide a lapping/polishing workpiece template having a main plate having an additional element in the form of a circumferentially notched gear-like periphery. 
     A yet further object of the present invention is to provide a lapping/polishing workpiece template having a main plate having a top surface and a bottom surface having a further additional element in the form of channels having a channel base and opposing channel walls placed within the top surface extending from a substantially central position to the periphery of said workpiece template. 
     A still yet further object of the present invention is to provide a lapping/polishing workpiece template substantially comprised of fiberglass-epoxy laminates. 
     Another object of the present invention is to provide a lapping/polishing workpiece template having a main plate comprising a fiberglass-epoxy laminate and having a frictionless material fixedly positioned to the bottom surface of the main plate. 
     Yet another object of the present invention is to provide a lapping and polishing workpiece template having a main plate comprising a fiberglass-epoxy laminate and having a Mylar backing adhesively affixed thereto. 
     Still yet another object of the present invention is to provide a lapping/polishing workpiece template having a main plate comprising a fiberglass-epoxy laminate and having a frictionless material fixedly positioned to the bottom surface of the main plate forming a frictionless work holder cavity base. 
     A further object of the present invention is to provide a lapping/polishing workpiece template having a main plate and a further additional element in the form of a backing plate being of substantially equal diameter affixed thereto. 
     A yet further object of the present invention is to provide a lapping/polishing workpiece template having a main plate, a backing plate with a top side and a bottom side with said top side fixedly positioned to said main plate and said bottom side having an adhesive layer. 
     A still yet further object of the present invention is to provide a lapping/polishing workpiece template having a main plate, a backing plate with a top side and a bottom side with said top side fixedly positioned to said main plate and said bottom side having an adhesive layer with a peelable removable covering thereon. 
     Another object of the present invention is to provide a lapping and polishing workpiece template having a main plate and a backing plate affixed thereto having at least one cavity positioned within said main plate. 
     Yet another object of the present invention is to provide a lapping/polishing workpiece template having a main plate comprising a fiberglass-epoxy laminate having a mylar backing adhesively affixed thereto whereby said mylar or other suitable frictionless material will cause the at least one wafer to rotate. 
     Still yet another object of the present invention is to provide a template cavity unit that will circumferentially conform to the workpiece template cavity whereby said template cavity unit can be inserted into the workpiece template cavity. 
     A further object of the present invention is to provide a template cavity unit having one or more cavities therein for inserting workpieces intended for lapping/polishing. 
     A yet further object of the present invention is to provide a plurality of shims for placement into the cavity or cavities of the workpiece template. 
     A still yet further of the present invention is to provide a lapping/polishing workpiece template having a shim that can be removably inserted into each of the plurality of cavities within said template. 
     Another object of the present invention is to provide a lapping/polishing workpiece template having a plurality of shims of varying thicknesses that can be removably inserted into each of the plurality of cavities within said template. 
     Yet another object of the present invention is to provide a lapping/polishing workpiece template having a shim or shims affixed to the base of the plurality of cavities within said template. 
     Still yet another object of the present invention is to provide a lapping/polishing workpiece template having an affixed shim or shims of smaller diameter than the diameter of the workpiece cavity diameter of the plurality of workpiece cavities within said template. 
     A further object of the present invention is to provide a lapping/polishing workpiece template having an affixed shim of smaller diameter than the diameter of the workpiece cavity diameter of the plurality of workpiece cavities within said template whereby the periphery of the wafer inserted therein will extend beyond the circumference of said shim. 
     A yet further object of the present invention is to provide a lapping/polishing workpiece template having a shim of smaller diameter than the diameter of the workpiece cavity diameter whereby the periphery of the wafer contained therein will extend beyond the circumference of said shim to reduce tapering of said wafer. 
     A still yet further object of the present invention is to provide a lapping/polishing workpiece template having a plurality of shims manufactured from a suitable material such as polyurethane. 
     Another object of the present invention is to provide a lapping and polishing workpiece template having a plurality of shims color coded for various thicknesses that can be removably inserted into each of the plurality of cavities within said template whereby said template can be used to produce wafers of various thicknesses. 
     Yet another object of the present invention is to provide a lapping and polishing workpiece template wherein a plurality of color coded shims representative of various thicknesses can be inserted into one or more of the workpiece cavities to produce wafers of a calculated thickness equal to the total workpiece template cavity thickness minus the total of the shim or shims inserted therein. 
     Additional objects of the present invention will appear as the description proceeds. 
     The present invention overcomes the shortcomings of the prior art by providing a method and device whereby employing the reusable workpiece template and selectively inserting shims having means for identifying various thicknesses, will produce semiconductor wafers of varying thicknesses. 
     In addition, the workpiece template having one or more cavities with a shim centrally positioned therein and being of smaller diameter than the cavity base will reduce tapering of the wafer. Additionally, the shims manufactured from a suitable frictionless material, such as mylar, will induce rotation of the wafer further reducing tapering of said wafers. 
     Furthermore the workpiece template having channels formed therein provides means for the lapping/polishing material to circulate across the planar surface of the workpiece template eliminating burnishing of the template and unwanted hydrodynamic properties of the lapping/polishing material associated with a fluid compressed between the two planar surfaces of the workpiece template and the lapping/polishing surface. 
     The foregoing and other objects and advantages will appear from the description to follow. In the description reference is made to the accompanying drawing, which forms a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. In the accompanying drawing, like reference characters designate the same or similar parts throughout the several views. 
     The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims. 
     LIST OF REFERENCE NUMERALS UTILIZED IN THE DRAWINGS 
       10  workpiece holder 
       12  lapping/polishing machine 
       14  lapping/polishing surface 
       16  supply of abrasive material 
       18  abrasive material 
       20  rotating heads 
       22  main plate 
       24  main plate cavity 
       26  top surface of main plate 
       28  bottom surface of main plate 
       30  main plate exterior wall 
       32  workpiece template cavity wall 
       34  workpiece template cavity base 
       36  frictionless material 
       38  adhesive layer 
       40  removable protective layer 
       42  gear-like notches 
       44  workpiece surface channel 
       46  channel base 
       48  channel wall 
       50  backing plate 
       52  backing plate top surface 
       54  backing plate bottom surface 
       56  template cavity unit 
       58  template cavity unit exterior wall 
       60  template cavity unit top surface 
       62  template cavity unit bottom surface 
       64  template cavity unit cavity 
       66  shim 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     In order that the invention may be more fully understood, it will now be described, by way of example, with reference to the accompanying drawing in which: 
     FIG. 1 is a perspective view of the present invention in use. 
     FIG. 2 is a perspective view of a single sided workpiece template. 
     FIG. 3 is a perspective view of a single sided workpiece template having a notched gear-like periphery edge. 
     FIG. 4 is a perspective view of a single sided workpiece template having a plurality of spiraling channels. 
     FIG. 5 is a cross sectional view of the workpiece template. 
     FIG. 6 is a perspective view of the present invention having channels. 
     FIG. 7 is a cross sectional view of the channeled workpiece template. 
     FIG. 8 is a perspective view of the workpiece template having cavity channels. 
     FIG. 9 is a cross sectional view of the channeled workpiece cavities. 
     FIG. 10 is a perspective view of the workpiece template of the present invention having a backing plate. 
     FIG. 11 is a cross sectional view of the workpiece template having a backing plate. 
     FIG. 12 is a perspective view of the template cavity unit. 
     FIG. 13 is a perspective view of the template cavity unit installed in the workpiece template cavity. 
     FIG. 14 is a cross sectional view of the installed template cavity unit. 
     FIG. 15 is a perspective view of the workpiece template having a shim positioned within the template cavity. 
     FIG. 16 is a cross sectional view of the workpiece template having a cavity shim. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following discussion describes in detail one embodiment of the invention (and several variations of that embodiment). This discussion should not be construed, however, as limiting the invention to those particular embodiments, practitioners skilled in the art will recognize numerous other embodiments as well. For definition of the complete scope of the invention, the reader is directed to appended claims. 
     FIG. 1 is a perspective view of the present invention  10  in use on a lapping/polishing machine  12 . The machine  12  has a lapping/polishing surface  14  having a delivery system  16  providing a constant supply of lapping/polishing material  18  deposited on the planar worksurface  14  of the lapping/polishing machine  12 . The lapping/polishing workpiece template  10  of the present invention has a plurality of silicon wafers, not shown in this figure, positioned within the workpiece template  10 . The lapping/polishing machine has a plurality of rotating heads  20  having the workpiece template  10  positioned thereunder causing the workpiece template to rotate while engaging the lapping/polishing surface  14 . 
     FIG. 2 is a perspective view of the workpiece template of the present invention  10 . Shown is the workpiece template having a main plate  22  having a plurality of spaced apart cavities  24  used to separate brittle workpieces during the lapping/polishing operation. The workpiece template  10  has a top surface  26  and a bottom surface  28  with the cavities passing therethrough. The workpiece template  10  also has a frictionless material  36  bonded to the bottom surface  28  of the workpiece template forming a frictionless base  34  for the workpiece cavities  24 . Positioned on the opposing side of the frictionless material  34  is a peelably removable covering  40  engaging an adhesive layer  38  that is used to engage the rotating heads  20  of the lapping/polishing machine  12  during the lapping/polishing operation. As the wafers are rotated underneath the lapping/polishing heads  20  they will have a tendancy to rotate within the workpiece template cavity  24  which the frictionless material  36  will not inhibit. 
     FIG. 3 is a perspective view of the workpiece template  10  of the present invention having an additional element in the form of a circumferentially notched gear-like periphery  42 . The notches  42  are used in a particular type of lapping/polishing machine having a plurality of interiorly and exteriorly positioned posts for engaging the notched gear-like teeth  42  of the workpiece template  10  and holding it therebetween having the similar end result of lapping/polishing wafers positioned within the cavities  24  of the workpiece template  10 . Also shown is the workpiece template  10  having a main plate  22  with a plurality of spaced apart cavities  24  for the positioning therein of wafers intended for lapping and/or polishing. The workpiece template  10  is comprised of a main plate  22  having a layer of frictionless material  36  bonded to the main plate  22  and forming the base of the workpiece cavities  34 . The base of the cavities  34  being significantly frictionless will not inhibit the rotation of the wafers during the lapping/polishing operation. 
     FIG. 4 is a perspective view of the present invention having an additional element in the form of channels  44  positioned within the top surface  26  of the main plate  22  of the workpiece template. The channels  42  have a channel base  46  and channel walls  48  extending from the exterior wall  30  of the main plate  22  across the top surface  28  providing means for the lapping/polishing material  18  to move freely between the workpiece cavities  24 . Also shown is the channeled workpiece template having a plurality of spaced apart cavities  24  passing therethrough that are used to hold wafers for the intended operation of lapping and/or polishing. The workpiece template  10  also has a frictionless material  36  bonded to the bottom surface  28  of the workpiece template forming a frictionless base  34  for the workpiece cavities  24 . Positioned on the opposing side of the frictionless material is a peelably removable covering  40  engaging an adhesive layer  38  that is used to engage the rotating heads  20  of the lapping/polishing machine  12  during the lapping/polishing operation. As the wafers are rotated underneath the lapping/polishing heads  20  they will have a tendancy to rotate within the workpiece template cavities  24  which the frictionless material  36  will not inhibit. The channels  44  are positioned to engage the lapping/polishing planar worksurface  14  having an amount of lapping/polishing material  16  thereon. In the prior illustrations the lapping/polishing material  16  has a largely planar surface with the workpieces extending from the workpiece template cavities  24 . As the wafers approach the thickness of the workpiece cavities  24  the fluid  16  between the workpiece template  10  and the lapping/polishing planar worksurface  14  diminishes causing the workpiece template  10  to burnish and/or the workpieces to ride out of the workpiece cavities  24 . Upon a cross sectional inspection of the processed wafers the edges are thinner than the center of the wafer. This also influences the rotational speed of the lapping/polishing operation and the number of wafers that can be placed in a template. The present invention overcomes these shortcomings by providing channels  44  that spiral in the same direction as the rotating heads  20 . Thereby causing the lapping/polishing material  16  into the channels  44  providing an abundance of lapping/polishing material  16  across the entire template surface  26 . 
     FIG. 5 is a cross sectional view of the workpiece template  10  of the present invention, taken from FIG. 2 as indicated. Shown is the workpiece template having a main plate  22  having a cavity  24  used to separate brittle workpieces during the lapping/polishing operation. The workpiece template  10  has a top surface  26  and a bottom surface  28  with the cavity  24  having a cavity wall  32  passing therethrough. The workpiece template  10  also has a frictionless material  36  bonded to the bottom surface  28  of the workpiece template by any means known within the art, such as adhesively. The frictionless material forms a frictionless cavity base  34  for the workpiece cavity  24 . Positioned on the opposing side of the frictionless material  36  is a peelably removable covering  40  engaging an adhesive layer  38  that is used to engage the rotating heads  20  of the lapping/polishing machine  12  during the lapping/polishing operation. As the wafers are rotated underneath the lapping/polishing heads  20  they will have a tendancy to rotate within the workpiece template cavity  24  which the frictionless material  36  will not inhibit. 
     FIG. 6 is a perspective view of the present invention wherein the spiraling channels  44  positioned within the top surface  26  of the main plate  22  of the workpiece template extend from the exterior wall  30  of the main plate  22  across the top surface  28  and through the workpiece template cavity walls  32  providing means for the lapping/polishing material  18  to move freely between and around the workpiece cavities  24  and workpiece cavity wall  32 . The workpiece template  10  also has a frictionless material  36  bonded to the bottom surface  28  of the workpiece template forming a frictionless base  34  for the workpiece cavities  24 . Positioned on the opposing side of the frictionless material is a peelably removable covering  40  engaging an adhesive layer  38  that is used to engage the rotating heads  20  of the lapping/polishing machine  12  during the lapping/polishing operation. As the wafers are rotated underneath the lapping/polishing heads  20  they will have a tendancy to rotate within the workpiece template cavities  24  which the frictionless material  36  will not inhibit. The channels  44  are positioned to engage the lapping/polishing planar worksurface  14  having an amount of lapping/polishing material  16  thereon. 
     FIG. 7 is a partial cross sectional view of the workpiece template  10  of the present invention, taken from FIG. 6 as indicated. Shown is the workpiece template having a main plate  22  having a cavity  24  used to separate brittle workpieces during the lapping/polishing operation. The workpiece template  10  has a top surface  26  and a bottom surface  28  with the cavity  24  having a cavity wall  32  passing therethrough. The top surface  26  of the main plate  22  has a channel  44  having a channel base  46  and channel wall  48  etched therein. The channel extends through the template cavity wall  32  whereby the abrasive material  18  will circulate freely around the wafers intended for lapping/polishing positioned within the workpiece cavity  24 . Also shown is the workpiece template  10  having a frictionless material  36  bonded to the bottom surface  28  of the workpiece template by any means known within the art, such as adhesively. The frictionless material forms a frictionless cavity base  34  for the workpiece cavity  24 . Positioned on the opposing side of the frictionless material  36  is a peelably removable covering  40  engaging an adhesive layer  38  that is used to engage the rotating heads  20  of the lapping/polishing machine  12  during the lapping/polishing operation. 
     FIG. 8 is a perspective view of the present invention wherein the spiraling channels  44  positioned within the top surface  26  of the main plate  22  of the workpiece template extend from the exterior wall  30  of the main plate  22  across the top surface  28  and through the workpiece template cavity walls  32  providing means for the lapping/polishing material  18  to move freely between and around the workpiece cavities  24  and workpiece cavity wall  32 . Also shown are channels  44  etched into the cavity base  34  of main plate  22 . Positioned on the bottom surface  28  is a peelably removable covering  40  engaging an adhesive layer  38  that is used to engage the rotating heads  20  of the lapping/polishing machine  12  during the lapping/polishing operation. FIG. 9 is a partial cross sectional view of the workpiece template  10  of the present invention, taken from FIG. 8 as indicated. Shown is the workpiece template having a main plate  22  having a cavity  24  used to separate brittle workpieces during the lapping/polishing operation that extends partially through main plate  22 . The workpiece template  10  has a top surface  26  and a bottom surface  28  with the cavity  24  having a cavity wall  32 . The top surface  26  of the main plate  22  has a channel  44  having a channel base  46  and channel wall  48  etched therein. The channel extends through the template cavity wall  32  whereby the abrasive material  18  will circulate freely around the wafers intended for lapping/polishing positioned within the workpiece cavity  24 . Positioned on the bottom surface of main plate  22  is a peelably removable covering  40  engaging an adhesive layer  38  that is used to engage the rotating heads  20  of the lapping/polishing machine  12  during the lapping/polishing operation. 
     FIG. 10 is a perspective view of the workpiece template of the present invention  10 . Shown is the workpiece template having a main plate  22  and a backing plate  50 . The main plate  22  has a plurality of spaced apart cavities  24  used to separate brittle workpieces during the lapping/polishing operation. The workpiece template  10  has a top surface  26  and a bottom surface  28  with the cavities passing therethrough with the backing plate top surface  52  forming the cavity base  34 . Positioned on the backing plate bottom surface  54  is a peelably removable covering  40  engaging an adhesive layer  38  that is used to engage the rotating heads  20  of the lapping/polishing machine  12  during the lapping/polishing operation. 
     FIG. 11 is a cross sectional view of the workpiece template  10  of the present invention, taken from FIG. 10 as indicated. Shown is the workpiece template having a main plate  22  having a cavity  24  used to separate brittle workpieces during the lapping/polishing operation. The workpiece template  10  has a top surface  26  and a bottom surface  28  with the cavity  24  having a cavity wall  32  passing therethrough. Engaging the bottom surface  28  of the main plate  22  is the top surface  52  of backing plate  50 . Positioned on the bottom surface  54  of backing plate  50  is a peelably removable covering  40  engaging an adhesive layer  38  that is used to engage the rotating heads  20  of the lapping/polishing machine  12  during the lapping/polishing operation. 
     FIG. 12 is a perspective view of an additional element of the present invention. Shown is the template cavity unit  56  having a diameter substantially equal to the main plate cavity  24  whereby non-standard workpieces having a template cavity unit  56  can be inserted into one or more of the main plate cavities  24  without having to create a specific template for the non-standard shapes. The template cavity unit top surface  60  coincides with the top surface of the main plate  26 . 
     FIG. 13 is a perspective view of the template cavity  56  positioned within the main plate cavity  24 . The template cavity unit exterior wall  58  engages the workpiece cavity wall  32  to prevent chattering of the unit  58 . The template cavity unit top surface  60  is in planar alignment with the top surface of main plate  26 . The template cavity unit bottom surface  62  engages the workpiece template cavity base  34 . The non-standard shape of the template cavity unit cavity  64  can be of any shape or any number of cavities that can be etched in the top surface of the template cavity unit  56 . 
     FIG. 14 is a cross sectional view of the template cavity unit positioned within the main plate cavity  24  of main plate  22 . The template cavity unit cavity  64  is contained within the template cavity unit. The template cavity unit bottom surface  62  engages the backing plate top surface  52 . The diameter of the template cavity unit  56  is substantially equivalent to the diameter of the main plate cavity  24  whereby the template cavity exterior wall  58  engages the workpiece template cavity wall  32 . In addition, once seated within the main plate cavity  24  the top surface of the template cavity unit  60  is in planar alignment with the top surface of the main plate  26 . Also shown is the workpiece holder  10  having a backing plate  50 . The backing plate  50  has an adhesive layer  38  with a protective element  40  whereby the workpiece holder  10  can be attached to the rotating heads  20  of the lapping/polishing machine  12 . 
     FIG. 15 is a perspective view of the workpiece template of the present invention  10 . Shown is the workpiece template having a main plate  22  and a backing plate  50 . The main plate  22  has a plurality of spaced apart cavities  24  used to separate brittle workpieces during the lapping/polishing operation having a shim  56  positioned at the base of cavity  24 . The workpiece template  10  has a top surface  26  and a bottom surface  28  with the cavities passing therethrough with the backing plate top surface  52  forming the cavity base  34  with shim  56  fixed thereto. Positioned on the backing plate bottom surface  54  is a peelably removable covering  40  engaging an adhesive layer  38  that is used to engage the rotating heads  20  of the lapping/polishing machine  12  during the lapping/polishing operation. 
     FIG. 16 is a cross sectional view of the workpiece template  10  of the present invention, taken from FIG. 15 as indicated. Shown is the workpiece template having a main plate  22  having a cavity  24  used to separate brittle workpieces during the lapping/polishing operation. The workpiece template  10  has a top surface  26  and a bottom surface  28  with the cavity  24  having a cavity wall  32  passing therethrough. Engaging the bottom surface  28  of the main plate  22  is the top surface  52  of backing plate  50 . Positioned on the bottom surface  54  of backing plate  50  is a peelably removable covering  40  engaging an adhesive layer  38  that is used to engage the rotating heads  20  of the lapping/polishing machine  12  during the lapping/polishing operation. 
     From the above description it can be seen that the method and apparatus for lapping and polishing silicon wafers of the present invention is able to overcome the shortcomings of prior art devices by providing a method and apparatus for lapping and polishing silicon wafers which is able to be used repeatedly to produce a plurality of silicon wafers. 
     The apparatus for lapping and polishing silicon wafers includes templates having a main disk substantially comprised of fiberglass-epoxy laminates and including cavities extending therein. A backing material adhesively affixed to the main disk and a layer formed of Mylar or other suitable frictionless material is affixed to the backing material. 
     A plurality of shims manufactured from a suitable material such as polyurethane may be affixed to the base of the cavities for adjusting the depth of the cavity. The shims are removably inserted into each of the plurality of cavities within the template. The plurality of shims are of various thickness=that can be removably inserted into each of the plurality of cavities within the template whereby the template can be used to produce wafers of various and/or calculated thickness=. 
     The method and apparatus for lapping and polishing silicon wafers is also able to reduce tapering of the wafer. Furthermore, the method and apparatus for lapping and polishing silicon wafers of the present invention is simple and easy to use and economical in cost to manufacture. 
     It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. 
     While certain novel features of this invention have been shown and described and are pointed out in the annexed claims, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention. 
     Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.