Chemical mechanical polishing apparatus and chemical mechanical polishing method thereof

Abstract

A chemical mechanical polishing apparatus and a chemical mechanical polishing method thereof are provided. The chemical mechanical polishing method at least includes the following steps. In step a, a positive pressure is formed between a polishing pad and a wafer. In step b, the wafer is driven to revolve around a first central axis. In step c, a polishing slurry is injected between the polishing pad and the wafer. In step d, the positive pressure formed on the wafer by the polishing pad is adjusted for change the contacting modes of the polishing pad and the wafer as well as the wafer removal rate.

1 . A chemical mechanical polishing apparatus, comprising:
 a carrier used for carrying a wafer to revolve around a first central axis;   a polishing platen used for pasting a polishing pad thereon, wherein a positive pressure is applied between the polishing pad and the wafer, the polishing platen drives the polishing pad to revolve around a second central axis;   a polishing slurry injector for injecting a polishing slurry into the gap between the wafer and the polishing pad; and   a controlling unit used for changing the contacting modes of the polishing pad and the wafer as well as the removal rate of the wafer by adjusting the positive pressure formed on the wafer by the polishing pad.   
     
     
         2 . The chemical mechanical polishing apparatus according to  claim 1 , wherein the contacting modes of the polishing pad and the wafer comprise a hydrodynamic-contacting mode, a semi-contacting mode and a full-contacting mode;
 at the hydrodynamic-contacting mode, the polishing pad and the wafer do not have any contact and the wafer has a first removal rate;   at the semi-contacting mode, the polishing pad and the wafer have partial contact and the wafer has a second removal rate;   at the full-contacting mode, the polishing pad and the wafer have full contact and the wafer has a third removal rate, wherein the first removal rate is smaller than the second removal rate, and the second removal rate is smaller than the third removal rate.   
     
     
         3 . The chemical mechanical polishing apparatus according to  claim 1 , wherein the controlling unit is used for adjusting the positive pressure by adjusting the gap between the polishing platen and the carrier. 
     
     
         4 . The chemical mechanical polishing apparatus according to  claim 1 , wherein the carrier drives the wafer to revolve at a first rotation rate, the polishing platen drives the polishing pad to revolve at a second rotation rate, and the controlling unit adjusts the relative velocity by adjusting the first rotation rate or the second rotation rate. 
     
     
         5 . The chemical mechanical polishing apparatus according to  claim 1 , wherein a relative velocity is formed between the wafer and the polishing pad, the controlling unit adjusts and the relative velocity during the polishing process. 
     
     
         6 . The chemical mechanical polishing apparatus according to  claim 1 , wherein the wafer comprises an insulating layer made from a low-K material. 
     
     
         7 . The chemical mechanical polishing apparatus according to  claim 6 , wherein the K dielectric value of the low-K material is smaller than  5 . 
     
     
         8 . The chemical mechanical polishing apparatus according to  claim 1 , further comprising:
 a flatness sensor used for sensing the flatness of the wafer; and   at least a supplementary polishing platen used for pasting a supplementary polishing pad thereon, the supplementary polishing platen polishes the wafer for supplementation according to the flatness of the wafer.   
     
     
         9 . The chemical mechanical polishing apparatus according to  claim 1 , wherein the wafer adopts copper wire manufacturing process. 
     
     
         10 . A chemical mechanical polishing method for polishing a wafer, wherein the chemical mechanical polishing method comprises the following steps:
 (a) applying a positive pressure between the polishing pad and the wafer;   (b) driving the wafer to revolve around a first central axis and driving the polishing pad to revolve around a second central axis;   (c) injecting a polishing slurry into the gap between the polishing pad and the wafer; and   (d) adjusting the positive pressure formed on the wafer by the polishing pad and for changing the contacting modes of the polishing pad and the wafer as well as the removal rate of the wafer.   
     
     
         11 . The chemical mechanical polishing method according to  claim 10 , wherein the contacting modes of the polishing pad and the wafer comprises a hydrodynamic-contacting mode, a semi-contacting mode and a full-contacting mode;
 at the hydrodynamic-contacting mode, the polishing pad and the wafer do not have contact and the wafer has a first removal rate;   at the semi-contacting mode, the polishing pad and the wafer have partial contact and the wafer has a second removal rate;   at the full-contacting mode, the polishing pad and the wafer have full contact and the wafer has a third removal rate, wherein the first removal rate is smaller than the second removal rate, and the second removal rate is smaller than the third removal rate.   
     
     
         12 . The chemical mechanical polishing method according to  claim 10 , wherein in the step (d), the positive pressure is adjusted by adjusting the gap between the polishing platen and the carrier. 
     
     
         13 . The chemical mechanical polishing method according to  claim 10 , wherein in the step (b), a relative velocity is formed between the wafer and the polishing pad, and in the step (d), the relative velocity is adjusted. 
     
     
         14 . The chemical mechanical polishing method according to  claim 10 , wherein in the step (d), the positive pressure and the relative velocity are adjusted at any time during the polishing process. 
     
     
         15 . The chemical mechanical polishing method according to  claim 10 ,  5  wherein the wafer has an insulating layer made from a low-K material. 
     
     
         16 . The chemical mechanical polishing method according to  claim 15 , wherein the K dielectric value of the low-K material is smaller than  5 . 
     
     
         17 . The chemical mechanical polishing method according to  claim 10 , further comprising:
 (e) sensing the flatness of the wafer; and   (f) polishing the wafer for supplementation according to the flatness of the wafer.   
     
     
         18 . The chemical mechanical polishing method according to  claim 10 , wherein the wafer adopts copper wire manufacturing process. 
     
     
         19 . A chemical mechanical polishing apparatus, comprising:
 a carrier for carrying a wafer, wherein the carrier drives the wafer to revolve around a first central axis, and the wafer has a plurality of wafer sub-regions each having a first thickness;   a poishing platen used for pasting a polishing pad thereon, wherein a positive pressure is applied between the polishing pad and each wafer sub-region, the poishing platen drives the polishing pad to revolve around a second central axis, and the polishing pad corresponding to each wafer sub-region has a second thickness which keeps changing along with the rotation of the wafer and the polishing pad;   a polishing slurry injector for injecting a polishing slurry between the wafer and the polishing pad; and   a controlling unit for adjusting the positive pressure applied to each wafer sub-region by the polishing pad according to the change relationship of between each first and second thickness corresponding to a wafer sub-region so as to change the contacting mode between the polishing pad and the wafer as well as the removal rate of the wafer.   
     
     
         20 . The chemical mechanical polishing apparatus according to  claim 19 , wherein the carrier drives the wafer to revolve around a first rotation rate, the poishing platen drives the polishing pad to revolve around a second rotation rate, and the controlling unit obtains the change relationship of the second thickness of each wafer sub-region according to the first rotation rate and the second rotation rate. 
     
     
         21 . A chemical mechanical polishing method for polishing a wafer, wherein the chemical mechanical polishing method at least comprises the following steps:
 (g) applying a positive pressure between a polishing pad and the wafer, wherein the wafer has a plurality of wafer sub-regions each having a first thickness;   (h) driving the wafer to revolve around a first central axis and driving the polishing pad t revolve around a second central axis, wherein the polishing pad corresponding to each wafer sub-region has a second thickness which keeps changing along with the rotation of the wafer and the polishing pad;   (i) injecting a polishing slurry between the polishing pad and the wafer; and   (j) adjusting the positive pressure applied to each wafer sub-region by the polishing pad according to the change relationship of between each first and second thickness corresponding to a wafer sub-region so as to change the contacting mode between the polishing pad and each wafer sub-region as well as the removal rate of each wafer sub-region.   
     
     
         22 . The chemical mechanical polishing method according to  claim 21 , wherein the step (h) drives the wafer to revolve around a first rotation rate and drives the polishing pad to revolve around a second rotation rate, and the step (j) obtains the change relationship of the second thickness of each wafer sub-region according to the first rotation rate and the second rotation rate. 
     
     
         23 . The chemical mechanical polishing method according to  claim 22 , wherein before the step (g), the chemical mechanical polishing method further comprises:
 (k) providing an all flat dummy wafer having a plurality of dummy sub-regions each corresponding to a wafer sub-region of the wafer respectively;   (l) disposing a plurality of gauges on each dummy sub-region respectively;   (m) driving the dummy wafer to revolve around the first central axis and driving the polishing pad to revolve around the second central axis, wherein the polishing pad corresponding to each dummy sub-region has the second thickness, which keeps changing along with the rotation of the dummy wafer and the polishing pad;   (n) measuring the change relationship of each second thickness by each gauge; and   (o) storing the change relationship of each second thickness.