Backside deposition tuning of stress to control wafer bow in semiconductor processing
A method of microfabrication is provided. A substrate having a working surface and having a backside surface opposite to the working surface is received. The substrate has an initial wafer bow resulting from one or more micro fabrication processing steps executed on the working surface of the substrate. The initial wafer bow of the substrate is measured and the initial wafer bow is used to generate an initial wafer bow value that identifies a degree of first order wafer bowing of the substrate. A correction film recipe based on the initial wafer bow value is identified. The correction film recipe specifies parameters of a correction film to be deposited on the backside surface of the substrate to change wafer bow of the substrate from the initial wafer bow to a modified wafer bow. The correction film on the backside surface of the substrate according to the correction film recipe is deposited. The correction film physically modifies internal stresses on the substrate and causes the substrate to have a modified bow with the predetermined wafer bow value.
1. A system for modifying wafer bow, the system comprising:
a metrology module included on a common platform configured to measure wafer bow of a substrate and generate an initial wafer bow value that identifies a degree of first order wafer bowing of the substrate, the substrate having a working surface and a backside surface opposite to the working surface, wherein the metrology module comprises a measurement arm including a sensor, and the measurement arm is configured to move when the sensor measures the wafer bow of the substrate;
a controller configured to receive the initial wafer bow value and identify parameters, based on the initial wafer bow value and a modified wafer bow value, a correction film recipe to change wafer bow of the substrate from an initial wafer bow to the modified wafer bow, the initial wafer bow resulting from one or more micro fabrication processing steps executed on the working surface of the substrate; and
a backside deposition module included on the common platform having a substrate holder, an automated substrate handling system configured to move the substrate from the metrology module after the initial wafer bow measurement to the backside deposition module, and substrate treatment components configured to deposit a correction film including alternating layers of different materials on the backside surface of the substrate according to the correction film recipe, wherein the parameters of the correction film recipe cause the deposition of the correction film to physically modify the internal stresses on the substrate to have the modified wafer bow having a modified wafer bow value of less than 300 microns in magnitude, and the correction film includes blanket films.
2. The system of claim 1 , wherein the correction film recipe identifies a thickness of material to be deposited on the backside surface of the substrate.
3. The system of claim 1 , wherein the correction film recipe identifies a type of material to be deposited on the backside surface of the substrate.
4. The system of claim 1 , wherein the correction film recipe identifies a deposition temperature of material to be deposited on the backside surface of the substrate.
5. The system of claim 1 , wherein the correction film recipe specifies parameters of the correction film to be deposited on the backside surface of the substrate.
6. The system of claim 1 , wherein the initial wafer bow value represents a substrate having a convex shape of the working surface, and wherein the modified wafer bow value of the modified wafer bow represents a concave shape of the working surface.
7. The system of claim 1 , wherein the correction film recipe identifies a number of atomic layer deposition cycles to execute using the backside deposition module.
8. The system of claim 1 , wherein the initial wafer bow has a value less than 100 microns in magnitude.
9. The system of claim 1 , wherein the backside deposition module uses chemical vapor deposition and wherein the correction film recipe includes an indication of a type of material, deposition temperature, and a final thickness of the correction film.
10. The system of claim 1 , wherein the metrology module measures z-height deviations across the backside surface of the substrate to generate the initial wafer bow value.
11. The system of claim 10 , wherein the metrology module measures z-height deviations using acoustic techniques.
12. The system of claim 1 , wherein deposition is executed on the backside surface while held with the working surface facing upwards.
13. The system of claim 1 , wherein the controller identifies the correction film recipe based on device parameters of the working surface of the substrate in addition to the initial wafer bow value.
14. The system of claim 1 , wherein the sensor is configured to measure the wafer bow of the substrate acoustically.
15. A system for modifying wafer bow, the system comprising:
a metrology module included on a common platform configured to measure wafer bow of a substrate and generate an initial wafer bow value that identifies a degree of first order wafer bowing of the substrate and includes z-height variation mapping, the substrate having a working surface and a backside surface opposite to the working surface, wherein the metrology module comprises a measurement arm including a sensor, and the measurement arm is configured to move when the sensor measures the wafer bow of the substrate;
a controller configured to receive the initial wafer bow value including the z-height variation mapping and identify parameters, based on the initial wafer bow value and a modified wafer bow value, a correction film recipe to change wafer bow of the substrate from an initial wafer bow to the modified wafer bow, the initial wafer bow resulting from one or more micro fabrication processing steps executed on the working surface of the substrate; and
a backside deposition module included on the common platform having a substrate holder, an automated substrate handling system configured to move the substrate from the metrology module after the initial wafer bow measurement to the backside deposition module, and substrate treatment components configured to deposit a correction film including alternating layers of different materials on the backside surface of the substrate according to the correction film recipe, wherein the correction film includes blanket films.
16. The system of claim 15 , wherein the parameters of the correction film recipe cause the deposition of the correction film to physically modify the internal stresses on the substrate to have the modified wafer bow having a modified wafer bow value of less than 300 microns in magnitude.
17. The system of claim 15 , wherein the correction film recipe identifies at least one selected from the group consisting of a thickness of material to be deposited on the backside surface of the substrate, a type of material to be deposited on the backside surface of the substrate and a deposition temperature of material to be deposited on the backside surface of the substrate.
18. The system of claim 15 , wherein the correction film recipe specifies parameters of the correction film to be deposited on the backside surface of the substrate.
19. The system of claim 15 , wherein the backside deposition module uses chemical vapor deposition, and the correction film recipe includes an indication of a type of material, deposition temperature, and a final thickness of the correction film.
20. The system of claim 15 , wherein the metrology module measures z-height deviations across the backside surface of the substrate to generate the initial wafer bow value.