Polishing with enhanced uniformity
A polishing head is presented. The polishing head includes a housing having top and bottom surfaces. The housing is formed from a single piece of material. The polishing head includes grooves disposed on the bottom surface and an inlet in communication with the grooves for coupling to a pressure medium supply to supply a pressure medium to the grooves. The pressure medium when supplied to the grooves exerts pressure on a template when attached to the bottom surface to provide back side pressure on a back surface of an article when temporally attached to the template.
1. A polishing head comprising:
a housing having a top surface and a bottom surface, wherein the housing is formed from a single piece of material;
concentric continuous annular grooves disposed on the bottom surface of the housing, wherein the concentric continuous annular grooves comprise independent concentric continuous annular grooves;
a template disposed on the bottom surface of the housing, wherein the template is configured to contact a wafer to be polished when temporally attached to the template to prevent slippage of the wafer; and
an inlet in communication with the grooves for coupling to a pressure medium supply to supply a pressure medium to the grooves, the pressure medium when supplied to the grooves exerts pressure on the template to provide back side pressure on a back surface of the wafer when temporally attached to the template.
2. The polishing head of claim 1 wherein:
the independent concentric continuous annular grooves form independent concentric continuous annular pressure zones on the template; and
an independent groove comprises at least one pressure supply inlet.
3. The polishing head of claim 1 comprises a mounting unit for attaching a template to the bottom of the housing, wherein the template covers the grooves, the template provides a mating surface on which the wafer to be polished is temporally attached for polishing.
4. The polishing head of claim 3 wherein
an independent groove comprises at least one pressure supply inlet.
5. The polishing head of claim 3 wherein the mounting unit is disposed in a recess for accommodating the template, wherein the grooves are disposed in the recess.
6. The polishing head of claim 5 wherein
an independent groove comprises at least one pressure supply inlet.
7. The polishing head of claim 1 comprises stainless steel.
8. The polishing head of claim 7 wherein
an independent groove comprises at least one pressure supply inlet.
9. The polishing head of claim 1 wherein the template covers the grooves, the template provides a mating surface on which an article to be polished is temporally attached for polishing.
10. The polishing head of claim 9 wherein
an independent groove comprises at least one pressure supply inlet.
11. The polishing head of claim 1 wherein the housing comprises:
a mounting unit having a top mounting unit surface which forms the top surface of the housing, the top surface is configured to attach the polishing head to a carrier of a polishing system; and
a base unit having a base unit bottom surface which forms the bottom surface of the housing, the bottom surface comprises a recess to accommodate the template, wherein the grooves are disposed in the recess.
12. The polishing head of claim 11 wherein
an independent groove comprises at least one pressure supply inlet.
13. The polishing head of claim 12 wherein flow rate of pressure media is controlled to produce the desired pressure profile for polishing the wafer.
14. A polishing head comprising:
a head housing having a top surface and a bottom surface, wherein the housing is formed from a single piece of material;
a plurality of independent concentric continuous annular grooves disposed on the bottom surface of the housing to provide a plurality of independently controlled concentric continuous annular pressure zones;
a template disposed on the bottom surface of the housing, wherein the template covers the grooves, the template is configured to contact a wafer to be polished when temporally attached to the template to prevent slippage of the wafer; and
inlets in communication with the grooves for coupling to a pressure medium supply to supply a pressure medium to the plurality of grooves to independently control the pressure exerted in the pressure zones during polishing when the wafer is temporally attached to the template.
15. A method of fabricating a semiconductor device comprising:
providing a substrate prepared with a device layer for polishing;
setting a pressure profile in a polishing head, wherein the polishing head comprising
a housing having a top surface and a bottom surface, wherein the housing is formed from a single piece of material,
concentric continuous annular grooves disposed on the bottom surface of the housing, wherein the concentric annular grooves comprise independent concentric continuous annular grooves,
a template disposed on the bottom surface of the housing, wherein the template is configured to contact the substrate when temporally attached to the template to prevent slippage of the substrate, and
an inlet in communication with the grooves for coupling to a pressure medium supply to supply a pressure medium to the grooves, the pressure medium when supplied to the grooves exerts pressure on the template to provide back side pressure on a back surface of the substrate when temporally attached to the template; and
polishing the substrate based on the pressure profile.
16. A method of fabricating a semiconductor device comprising:
providing a substrate prepared with a device layer for polishing;
setting a pressure profile in a polishing head which includes a plurality of independently controllable pressure zones, wherein the polishing head comprising
a housing having a top surface and a bottom surface, wherein the housing is formed from a single piece of material,
concentric continuous annular grooves disposed on the bottom surface of the housing, wherein the concentric annular grooves comprise independent concentric continuous annular grooves,
a template disposed on the bottom surface of the housing, wherein the template is configured to contact the substrate when temporally attached to the template to prevent slippage of the substrate, and
an inlet in communication with the grooves for coupling to a pressure medium supply to supply a pressure medium to the grooves, the pressure medium when supplied to the grooves exerts pressure on the template to provide back side pressure on a back surface of the substrate when temporally attached to the template; and
polishing the substrate based on the pressure profile.
17. The polishing head in claim 1 comprises stainless steel.