Polishing method and polishing apparatus permitting control of polishing time at a high accuracy
AssigneeNEC Corporation
InventorShinichiro Kakita
Life of this patent
Estimating the term…
Abstract
A preceding wafer having an aluminum wiring and a silicon oxide film formed on an insulating film is chemico-mechanically polished. In the stage in which surface irregularities of the silicon oxide film are eliminated, polishing is discontinued. On the basis of the result, a polishing time is determined in accordance with the following formula: T=(D1−D2)/v+t1 where, D1 represents the thickness in the stage in which polishing is discontinued; D2, a target thickness; t1, a time required from the initial thickness to reach the thickness D1; and the polishing rate of the material of the silicon oxide film formed on a flat substrate is denoted as v.
Claims7
A polishing method of chemico-mechanically polishing a film formed on the surface of wafer having surface irregularities to a target thickness, said method comprising the steps of:
- determining a predicted required time for the former half of polishing by use of polishing data acquired upon polishing the preceding wafer of a type similar to that of the wafer to be polished;
- determining a predicted required time for the latter half of polishing by use of a polishing rate of the component materials of said film formed on a flat substrate;
- using a value obtained by summing up these predicted required times;
- and
- chemico-mechanically polishing a wafer to be polished.
A polishing method of chemico-mechanically polishing a film formed on the surface of a wafer having surface irregularities to a target thickness, said method comprising the steps of:
- acquiring a polishing rate v of component materials of said film formed on a flat substrate;
- chemico-mechanically polishing a preceding wafer of the same type as the wafer to be polished, discontinuing polishing in a stage prior to reaching said target thickness, and measuring the film thickness in this stage;
- calculating T as defined by the following formula (I):
- T=(D1−D2)/v+t1 (I)
- where, D1 represents the film thickness upon discontinuing polishing;
- D2 represents the target film thickness;
- and t1 represents the time required from the initial thickness to the thickness D1;
- and
- chemico-mechanically polishing the wafer to be polished, using a value obtained with reference to T as the polishing time.
A polishing apparatus for chemico-mechanically polishing a film formed on the surface of a wafer having surface irregularities to a target thickness, said apparatus comprising:
- a storage unit which stores polishing data acquired for a preceding wafer of the same type as the wafer to be polished and a polishing rate of component materials of said film formed on a flat substrate;
- a polishing time managing unit which determines a predicted required time for a former half by using said polishing data read out from said storage unit, determining a predicted required time for the latter half by using said polishing rate read out from said storage unit, and obtaining a polishing time by summing up these predicted required times;
- and
- a polishing unit which chemico-mechanically polishes the wafer for the polishing time obtained by said polishing time managing unit.
A polishing apparatus for chemical-mechanically polishing a film formed on the surface of a wafer having surface irregularities to a target thickness, said apparatus comprising:
- a polishing unit which chemico-mechanically polishes a wafer;
- a thickness control unit which controls the thickness of a film provided on the surface of the water;
- a thickness measuring unit which measures the thickness of the film provided on the surface of the wafer;
- a storage unit which stores data regarding polishing conditions;
- and
- a polishing time managing unit managing a polishing time for the wafer;
- when polishing of a preceding wafer arranged in said polishing unit is started, said thickness control unit requesting said polishing unit to discontinue polishing before reaching a target thickness D2;
- said thickness measuring unit measuring the thickness D1 of said film in a stage in which discontinuance of polishing is requested, and storing the thickness D1 and a polishing time t1 required before reaching the thickness D1;
- said polishing time managing unit reading out a polishing rate v of the material of the film formed on a flat substrate, the thickness D1 and the polishing time t1 required before reaching the thickness D1, stored previously in said storage unit from said storage unit, calculating a value of T defined by the following formula (I):
- T=(D1−D2)/v+t1 (I)
- where, D1 represents the thickness in the stage in which polishing is discontinued;
- D2, a target thickness;
- and t1, a time required before reaching the thickness D1 from the initial thickness, determining a polishing time of the wafer from this value, and storing the same in said storage unit;
- said polishing unit reading out, when a wafer to be polished is arranged on said polishing unit, said polishing time stored in said storage unit, and chemico-mechanically polishing the wafer to be polished for the read-out polishing time.
Dependencies are inferred from the claim text.