In-situ lithography pattern enhancement with localized stress treatment tuning using heat zones
Aspects of the present disclosure provide a method for optimizing wafer shape. For example, the method can include receiving a wafer having a working surface for one or more devices to be fabricated thereon and a backside surface opposite to the working surface, measuring the wafer to identify bow measurement of the wafer, and forming a stress-modification film on the backside surface of the wafer. The stress-modification film can be reactive to heat such that applied heat modifies an internal stress of the stress-modification film. The method can also include applying a pattern of heat onto the stress-modification film to modify the internal stress of the stress-modification film, the pattern of heat corresponding to the bow measurement.
1. A method, comprising:
receiving a wafer having a working surface for one or more devices to be fabricated thereon, and a backside surface opposite to the working surface;
measuring the wafer to identify bow measurement of the wafer;
forming a first stress-modification film on the working surface of the wafer, the first stress-modification film reactive to heat such that applied heat modifies an internal stress of the first stress-modification film;
forming a second stress-modification film on the backside surface of the wafer, the second stress-modification film reactive to heat such that applied heat modifies an internal stress of the second stress-modification film;
applying a first pattern of heat onto the first stress-modification film to modify the internal stress of the first stress-modification film; and
applying a second pattern of heat onto the second stress-modification film to modify the internal stress of the second stress-modification film,
wherein the first and second patterns of heat correspond to the bow measurement of the wafer.
2. The method of claim 1 , wherein at least one of the first and second patterns of heat is applied by a laser.
3. The method of claim 1 , wherein the bow measurement includes a plurality of first sub-bow measurements, and the first pattern of heat is applied by a plurality of heating units that correspond to the first sub-bow measurements.
4. The method of claim 3 , wherein the heating units are installed on a wafer chuck.
5. The method of claim 1 , wherein forming a first stress-modification film is performed prior to measuring the wafer to identify bow measurement of the wafer.
6. The method of claim 5 , wherein forming a second stress-modification film is performed prior to measuring the wafer to identify bow measurement of the wafer.
7. The method of claim 1 , wherein forming a first stress-modification film is performed subsequent to measuring the wafer to identify bow measurement of the wafer.
8. A system, comprising:
a bow measurement device configured to measure a wafer to identify bow measurement of the wafer, the wafer having a working surface for one or more devices to be fabricated thereon, and a backside surface opposite to the working surface;
a stress-modification film formation device configured to form first and second stress-modification films, the first and second stress-modification films reactive to heat such that applied heat modifies internal stresses of the first and second stress-modification films;
a heat generator configured to generate a pattern of heat; and
a controller coupled to the bow measurement device, the stress-modification film formation device and the heat generator, the controller configured to control the bow measurement device to measure the wafer to identify the bow measurement of the wafer, control the stress-modification film formation device to form the first and second stress-modification films on the backside surface and working surface of the wafer, respectively, and control the heat generator to generate and apply the pattern of heat onto the first stress-modification film and/or the first and second stress-modification films, the pattern of heat corresponding to the bow measurement.
9. The system of claim 8 , wherein the heat generator includes a laser.
10. The system of claim 8 , wherein the bow measurement includes a plurality of sub-bow measurements, and the heat generator includes a plurality of heating units that correspond to the sub-bow measurements.
11. The system of claim 10 , further comprising a wafer chuck, wherein the heating units are installed on the wafer chuck.