Methods and apparatus for the chemical mechanical planarization of electronic devices
View Patent ↗Method and apparatus for chemically and mechanically planarizing the surface of a silicon wafer which includes a compressible non-cellualar lapping surface and a slurry disposed between the wafer and the lapping surface.
1. An apparatus for chemically and mechanically planarizing a surface of a workpiece comprising:
a non-cellular lapping surface;
workpiece mounting means for mounting said workpiece to expose said workpiece surface to said lapping surface;
an abrasive slurry disposed between said workpiece surface and said lapping surface; and
means for relatively moving said lapping surface and said workpiece mounting means such that said workpiece surface is contacted and planarized by said lapping surface.
2. An apparatus as claimed in claim 1 , wherein said lapping surface is made from a soft and pliable material that conforms to integrated circuit device layers formed on said workpiece surface and resists damage to said integrated circuit device layers.
3. An apparatus as claimed in claim 2 , wherein said lapping surface is made from fused polyethylene, flexibilized epoxy or non-cellular urethane.
4. An apparatus as claimed in claim 1 , wherein said abrasive slurry comprises:
about 5-20% by weight of a chemical agent having a particle size of about 10-200 nanometers and being selected from a group consisting of a hydroxide and potassium fluoride; and
a mechanical agent selected from a group consisting of colloidal silica, cerium oxide and alumina.
5. An apparatus as claimed in claim 4 , wherein said abrasive slurry comprises about 11% by weight of said chemical agent and said particle size is about 30-80 nanometers.
6. A method for chemically and mechanically planarizing a workpiece surface comprising the following steps:
providing a non-cellular lapping surface; and
effecting relative movement between said lapping surface and said workpiece surface in the presence of an abrasive slurry to planarize said workpiece surface.
7. A method as claimed in claim 6 , and further comprising the step of making said lapping surface from a soft and pliable material that will conform to integrated circuit device layers formed on said workpiece surface and resist damage to said integrated circuit device layers.