Metal-less bond grinding stone, and electrolytic dressing grinding method and apparatus using the grinding stone

Abstract

There is here disclosed a metal-less bond grinding stone for protrusion of grains on the grinding stone by electrolytic dressing, comprising abrasive grains and a bond portion for holding the abrasive grains, wherein the bond portion comprises a carbon-containing nonmetallic material alone. Furthermore, this metal-less bond grinding stone is used, whereby a current which is allowed to flow between the grinding stone and the electrode is controlled within a desired range. In this way, environmental pollution with a waste liquid containing heavy metal ions and metal contamination of device wafers can be prevented, and a mirror-like high-quality level ground surface can be obtained with a satisfactory efficiency.

What is claimed is:  
     
         1 . A metal-less bond grinding stone for dressing a ground surface by electrolytic dressing, comprising: 
 abrasive grains and a bond portion for holding the abrasive grains, wherein the bond portion comprises a carbon-containing nonmetallic material alone.    
     
     
         2 . The metal-less bond grinding stone according to  claim 1 , which comprises a mixture of abrasive grains, carbon powder and resin powder and which is formed by sintering the mixture under pressure at a softening temperature lower than a resin melting temperature.  
     
     
         3 . The metal-less bond grinding stone according to  claim 2 , wherein a blend ratio of carbon to the resin is about 20% or more and about 30% or less.  
     
     
         4 . The metal-less bond grinding stone according to  claim 1 , which comprises a mixture of the abrasive grains and carbon-containing powder and which is obtained by sintering the mixture to impart conductivity and mechanical strength to the carbon-containing powder.  
     
     
         5 . The metal-less bond grinding stone according to  claim 1 , which comprises a mixture of the abrasive grains and resin powder and which is obtained by sintering the mixture to carbonize at least a part of the resin powder.  
     
     
         6 . An electrolytic in-process dressing grinding method comprising a step of applying a voltage between a metal-less bond grinding stone (1) having a bond portion comprising a carbon-containing nonmetallic material alone and an electrode (2) while a conductive grinding fluid (3) is allowed to flow between the metal-less bond grinding stone (1) and the electrode (2), and a step of grinding a work piece (4) while the grinding stone is subjected to electrolytic dressing, wherein a current which is allowed to flow between the grinding stone and the electrode is controlled within a desired range.  
     
     
         7 . An electrolytic dressing grinding apparatus using a metal-less bond grinding stone, which comprises a metal-less bond grinding stone (1) having a bond portion comprising a carbon-containing nonmetallic material alone, a carbon electrode (2) which is located at a distance from a grinding surface of the metal-less bond grinding stone (1) and at least whose side opposite to the grinding stone is made from a carbon material, a grinding fluid supply means (6) for causing a conductive grinding fluid (3) not containing any heavy metal ions to flow between the grinding stone and the electrode, and an power source unit (8) for electrolytic dressing which applies a voltage between the grinding stone and the electrode and which controls the current flowing between them within a predetermined range.