Apparatus for shaping the surface of chemical mechanical polishing pads

Abstract

The present invention provides apparati for pre-conditioning polymeric, preferably, porous polymeric, chemical mechanical (CMP) polishing pads or layers and polishing a substrate that comprise a rotary grinder assembly having a rotor with a grinding surface of a porous abrasive material, a flat bed platen for holding the CMP polishing pad or layer in place so that the grinding surface of the rotary grinder is disposed above and parallel to the surface of the flat bed platen to form an interface of the surface of the CMP polishing layer and the porous abrasive material, and a substrate holder located above and parallel to a top surface of the flat bed platen and to which a CMP substrate is attached, thereby creating a polishing interface between the surface of the substrate and the CMP polishing layer wherein the substrate holder rotates independently from the rotary grinder assembly and the flat bed platen.

We claim: 
     
         1 . An apparatus to provide pre-conditioned polymeric chemical mechanical (CMP) polishing pads or layers with a pad surface microtexture and to polish a substrate comprising a rotary grinder assembly having a wheel or rotor with a grinding surface of a porous abrasive material, a flat bed platen for holding the CMP polishing layer in place, the grinding surface of the rotary grinder disposed above and parallel to or substantially parallel to the surface of the flat bed platen to form an interface of the surface of the CMP polishing layer and the porous abrasive material, and a substrate holder located above and parallel to a top surface of the flat bed platen so as not to overlap with the area over which the rotary grinder assembly is disposed and to which a CMP substrate is attached, thereby creating a polishing interface between the surface of the substrate and the CMP polishing layer wherein the substrate holder rotates independently from the rotary grinder assembly and the flat bed platen. 
     
     
         2 . The apparatus of the present invention as claimed in  claim 1 , wherein the flat bed platen holds the CMP polishing layer in place by vacuum. 
     
     
         3 . The apparatus of the present invention as claimed in  claim 1 , wherein the CMP polishing layer has a radius extending from its center point to its outer periphery and the grinding surface of the wheel or rotor of the rotary grinder assembly has a diameter equal to or greater than the radius of the CMP polishing layer. 
     
     
         4 . The apparatus of the present invention as claimed in  claim 3 , wherein the diameter of the rotary grinder assembly is equal to the radius of the CMP polishing layer. 
     
     
         5 . The apparatus of the present invention as claimed in  claim 1 , wherein the wheel or rotor of the rotary grinder assembly is positioned so that the outer periphery of its grinding surface rests directly over the center of the CMP polishing layer during grinding. 
     
     
         6 . The apparatus of the present invention as claimed in  claim 1 , wherein the wheel or rotor of the rotary grinder assembly and the CMP polishing layer and flat bed platen each rotate during the grinding of the CMP polishing layer. 
     
     
         7 . The apparatus of the present invention as claimed in  claim 1 , wherein the rotary grinder assembly comprises a drive housing including a motor or rotary actuator and a vertically disposed axle connecting with and driven by the motor or rotary actuator which extends into a drive housing and connects at its lower end via a mechanical linkage to the wheel or rotor so that it spins at a desired rate of revolutions per minute (rpm). 
     
     
         8 . The apparatus of the present invention as claimed in  claim 1 , wherein the in the drive housing, the vertically disposed axle comprises a ball screw or secondary servo motor located where the axle connects to the motor or rotary actuator, at the mechanical linkage of the axle to the wheel or rotor, or both locations, whereby the wheel or rotor of the rotary grinder assembly can be fed downward at a set, incremental rate. 
     
     
         9 . The apparatus of the present invention as claimed in  claim 1 , further comprising a conduit, hose, nozzle or valve for blowing compressed inert gas or air intermittently or continuously, and positioned to blow the inert gas or air into the interface of the surface of the CMP polishing layer material and the porous abrasive material so as to impinge upon the porous abrasive material during grinding, and, separately, comprising a second conduit, hose or valve for blowing compressed inert gas or air upward from a point just below the periphery of the rotary grinder assembly so as to impinge upon the porous abrasive material during grinding. 
     
     
         10 . The apparatus of the present invention as claimed in  claim 1 , wherein the substrate holder has a diameter smaller than the radius of the CMP polishing layer or pad held on the flat bed platen and, further wherein, the substrate holder is mechanically linked to or mounted on a first actuator for rotating the grinder about a central axis; and a second actuator for pressing the substrate holder against the CMP polishing layer or pad. 
     
     
         11 . The apparatus of the present invention as claimed in  claim 1 , wherein the entire apparatus is enclosed inside an airtight enclosure.