Apparatus and methods for aligning a center of mass with a rotational axis of a shaft or spindle

Abstract

Centering elements may effectively reduce the clearance between a shaft and a rotatable element, such as a blade-fixing flange of a dicing saw for use with semiconductor substrates or carrier substrates. Centering elements may be used to substantially align a center of mass of a rotatable element installed onto the shaft with the axis of rotation of the shaft. Centering element may position the center of mass of a rotatable element at a position that is in substantial alignment with the axis of rotation. Methods for modifying the balance of components of saw assemblies which methods employ the use of centering elements, are also disclosed. Multiple fixtures as well as multiple centering elements may be employed. In addition, one centering element may position more than one fixture.

1 . A centering element for aligning a center of mass of a rotatable element of a saw with an axis of rotation of a saw spindle, comprising at least one member configured to be located at least partially between the rotatable element and the saw spindle.  
   
   
       2 . The centering element of  claim 1 , wherein the at least one member is compressible and resilient.  
   
   
       3 . The centering element of  claim 1 , wherein the at least one member is configured to be pressed against at least one of the rotatable element and the saw spindle.  
   
   
       4 . The centering element of  claim 1 , wherein the at least one compressible, resilient member comprises an O-ring configured to be positioned adjacent to the inner edge of the rotatable element.  
   
   
       5 . The centering element of  claim 1 , wherein the at least one compressible, resilient member comprises an x-ring configured to be positioned adjacent to an inner edge of the rotatable element.  
   
   
       6 . The centering element of  claim 1 , wherein the at least one compressible, resilient member comprises a plurality of springs positioned relative to an inner edge of the rotatable element so as to contact an outer surface of the saw spindle at a corresponding plurality of discrete locations upon assembly of the rotatable element on the saw spindle.  
   
   
       7 . The centering element of  claim 6 , wherein each spring of the plurality of springs comprises a coiled spring.  
   
   
       8 . The centering element of  claim 1 , wherein the at least one compressible, resilient member is configured to be partially received by a recess formed in an outer surface of the saw spindle upon assembly of the rotatable element on the saw spindle.  
   
   
       9 . The centering element of  claim 1 , wherein the at least one compressible, resilient member is configured to transmit torque of the saw spindle during rotation thereof to the rotatable element.  
   
   
       10 . The centering element of  claim 1 , wherein the saw is configured for use in dicing semiconductor substrates or carrier substrates.  
   
   
       11 . A method for modifying the balance of components of a saw assembly, comprising: 
 assembling at least one rotatable element with a spindle of the saw assembly with at least one centering element located at least partially between the at least one rotatable element and the spindle so as to align a center of mass or a rotational axis of the at least one rotatable element with an axis of rotation of the spindle.    
   
   
       12 . The method of  claim 11 , wherein assembling includes assembling the at least one rotatable element and the spindle with at least one O-ring located at least partially therebetween.  
   
   
       13 . The method of  claim 11 , wherein assembling includes assembling the at least one rotatable element and the spindle with at least one spring located at least partially therebetween.  
   
   
       14 . The method of  claim 13 , wherein assembling comprises assembling the at least one rotatable element and the spindle with at least one coiled spring located at least partially therebetween.  
   
   
       15 . The method of  claim 11 , wherein assembling comprises assembling the at least one rotatable element and the spindle with a plurality of centering elements located at least partially therebetween.  
   
   
       16 . The method of  claim 15 , wherein assembling includes assembling with the spindle at least one rotatable element including the plurality of centering elements at different axial positions of the at least one rotatable element.  
   
   
       17 . The method of  claim 15 , wherein assembling includes assembling with the spindle at least one rotatable element including the plurality of centering elements at different radial positions of the at least one rotatable element.  
   
   
       18 . The method of  claim 11 , wherein assembling includes assembling with the spindle the at least one rotatable element with the at least one centering element positioned partially within at least one recess in an inner surface of the at least one rotatable element.  
   
   
       19 . The method of  claim 11 , wherein assembling includes assembling the at least one rotatable element with the spindle, the at least one centering element positioned partially within at least one recess in an outer surface of the spindle.  
   
   
       20 . The method of  claim 11 , further comprising: 
 measuring a clearance between the at least one rotatable element and the spindle before the at least one centering element is assembled with the spindle or the at least one rotatable element.    
   
   
       21 . The method of  claim 20 , further comprising: 
 selecting the at least one centering element based at least in part on the clearance.    
   
   
       22 . The method of  claim 11 , further comprising: 
 measuring a rotational balance of the at least one rotatable element during rotation of the spindle.    
   
   
       23 . The method of  claim 22 , further comprising: 
 repositioning the center of mass of the at least one rotatable element based on measuring the rotational balance.    
   
   
       24 . The method of  claim 11 , further comprising: 
 assembling at least another rotatable element on the spindle with a centering element located at least partially between the at least another rotatable element and the spindle.    
   
   
       25 . The method of  claim 24 , wherein assembling the at least another rotatable element comprises assembling the at least another rotatable element adjacent to the at least one rotatable element.  
   
   
       26 . The method of  claim 25 , wherein assembling the at least one rotatable element and assembling the at least another rotatable element comprise assembling a complementary pair of blade-securing flanges at axially adjacent positions along the spindle.  
   
   
       27 . The method of  claim 26 , further comprising: 
 assembling a dicing blade on the spindle, between the complementary pair of blade-securing flanges.    
   
   
       28 . The method of  claim 27 , further comprising: 
 centering the dicing blade between the complementary pair of blade-securing flanges.    
   
   
       29 . The method of  claim 24 , wherein assembling each of the at least one rotatable element and the at least another rotatable element with the spindle comprises assembling the at least one rotatable element and the at least another rotatable element, along with a common centering element, with the spindle.