Micro-layer cmp polishing subpad

Abstract

The polishing pad has a polymeric matrix, a polishing surface useful for polishing at least one of semiconductor, magnetic and optical substrates and a bottom surface; a porous subpad adhered to the bottom surface of the polishing pad. The porous subpad includes a nonporous microlayer for securing the polishing pad to the porous subpad. The porous polymer network contains i) a single layer of closed cell micropores adjacent the nonporous microlayer for transitioning compressive forces from the bottom surface of the polishing pad to the porous subpad; and ii) a multilayer of closed cell, open cell or a mixture of closed and open cell micropores adjacent the single layer of closed cell micropores.

We claim: 
     
         1 . A chemical mechanical polishing pad comprising:
 a polishing pad having a polymeric matrix, a polishing surface useful for polishing at least one of semiconductor, magnetic and optical substrates and a bottom surface;   a porous subpad adhered to the bottom surface of the polishing pad, the porous subpad including:   a nonporous microlayer for securing the polishing pad to the porous subpad, the nonporous microlayer being flexible and forming a micro-scale conformal coating on the bottom surface of the polishing pad and the nonporous layer is contiguous with the bottom surface of the polishing pad;   a porous polymer network, the porous polymer network containing:   i) a single layer of closed cell micropores adjacent the nonporous microlayer for transitioning compressive forces from the bottom surface of the polishing pad to the porous subpad; and   ii) a multilayer of closed cell, open cell or a mixture of closed and open cell micropores adjacent the single layer of closed cell micropores wherein the multilayer of closed cell, open cell or a mixture of closed and open cell micropores are gas filled and the multilayer of closed cell, open cell or a mixture of closed and open cell micropores remains gas filled during an entire polishing life of the polishing pad.   
     
     
         2 . The polishing pad of  claim 1  wherein the nonporous microlayer has an average thickness of less than fifty percent of an average diameter of the multilayer micropores within the polymer network. 
     
     
         3 . The polishing pad of  claim 1  wherein the multilayer includes the mixture of closed cell and open cell micropores and the closed cells are spherical and the open cell pores include ovoid-shaped micropores. 
     
     
         4 . The polishing pad of  claim 1  wherein the multilayer includes a macro features that extend into the subpad for adjusting polishing profile of the chemical mechanical polishing pad. 
     
     
         5 . The polishing pad of  claim 1  wherein the polymer matrix includes closed cell micropores, the closed cells are micropores and a bottom surface of the polishing pad includes opened micropores and the nonporous microlayer is contiguous with the opened micropores to at least partially fill the opened micropores of the bottom surface of the polishing pad. 
     
     
         6 . A chemical mechanical polishing pad comprising:
 a polishing pad having a polymeric matrix, a polishing surface useful for polishing at least one of semiconductor, magnetic and optical substrates and a bottom surface;   a porous subpad adhered to the bottom surface of the polishing pad, the porous subpad including:   a nonporous microlayer for securing the polishing pad to the porous subpad, the nonporous microlayer being flexible and forming a micro-scale conformal coating on the bottom surface of the polishing pad and the nonporous layer is contiguous with the bottom surface of the polishing pad;   a porous polymer network, the porous polymer network containing:   i) a single layer of closed cell micropores adjacent the nonporous microlayer for transitioning compressive forces from the bottom surface of the polishing pad to the porous subpad; and   ii) a multilayer of closed cell, open cell or a mixture of closed and open cell micropores adjacent the single layer of closed cell micropores wherein the multilayer of closed cell, open cell or a mixture of closed and open cell micropores are gas filled and the multilayer of closed cell, open cell or a mixture of closed and open cell micropores remains gas filled during an entire polishing life of the polishing pad and the polishing pad has a porosity and the porous subpad has a porosity greater than the porosity of the polishing pad.   
     
     
         7 . The polishing pad of  claim 6  wherein the nonporous microlayer has an average thickness of less than fifty percent of an average diameter of the multilayer micropores within the polymer network. 
     
     
         8 . The polishing pad of  claim 6  wherein the multilayer includes the mixture of closed cell and open cell micropores and the closed cells are spherical and the open cell pores include ovoid-shaped micropores. 
     
     
         9 . The polishing pad of  claim 6  wherein the multilayer includes a series of macro features that extend into the subpad for adjusting polishing profile of the chemical mechanical polishing pad. 
     
     
         10 . The polishing pad of  claim 6  wherein the polishing layer has a bottom surface and the bottom surface includes annular grooves that extend into the polishing layer without piercing through the polishing surface of the polishing layer and the subpad fills the annular grooves.