Combination of inline metrology and on tool metrology for advanced packaging
Aspects of the present disclosure generally relate to a digital lithography system and methods for alignment resolution with the digital lithography system. The digital lithography system includes a metrology system configured to improve overlay alignment for different layers of the lithography process. The metrology system includes an inline metrology system (IMS) in combination with an on tool metrology system (OTM), which enable substrate overlay alignment and die placement correction. The inline metrology system may be positioned on an inline metrology tool and the on tool metrology system is positioned on a digital lithography tool. The inline metrology system facilitates measurement of high-throughput measurement inline metrology data for marks such as die marks and global alignment marks for verification of process stability and die placement data for digital data correction. This inline metrology data can be compared with a design file to determine offsets for the digital data correction.
1. A method for processing a substrate, comprising:
loading a substrate onto a stage of an inline metrology tool comprising at least one scanning device, wherein the substrate comprises:
one or more packages comprising one or more die having die marks formed on the one or more die; and
one or more global alignment marks formed on the substrate;
scanning the substrate with the at least one scanning device to obtain a first set of coordinate data, wherein the first set of coordinate data comprises an actual location of the one or more global alignment marks and an actual location of the die marks;
establishing general location information of the substrate based on the actual location of the one or more global alignment marks;
determining the actual location of the die marks relative to the general location information;
comparing the actual location of the die marks relative to the general location information with a design location of the die marks relative to the general location information to determine a correction factor;
loading the substrate onto a stage of a maskless lithography tool comprising at least one scanning device and at least one image projection system;
scanning the substrate with the at least one scanning device of the maskless lithography tool to establish the general location information of the substrate based on the actual location of the one or more global alignment marks; and
patterning subsequent layers onto the substrate using a digital correction mask and the at least one image projection system, wherein the digital correction mask is based, at least in part on the correction factor.
2. The method of claim 1 , wherein the one or more global alignment marks have a width in a range from about 50 microns to about 1000 microns.
3. The method of claim 2 , wherein the die marks have a width of 50 microns or less.
4. The method of claim 1 , wherein establishing the general location information of the substrate, comprises:
establishing a general coordinate system of the substrate using the actual location of the one or more global alignment marks.
5. The method of claim 4 , wherein comparing the actual location of the die marks relative to the general location information with the design location of the die marks relative to the general location information to determine the correction factor comprises comparing the actual location of the die marks relative to the general coordinate system to determine shifting and rotation of the one or more die relative to the general coordinate system.
6. The method of claim 1 , wherein the first set of coordinate data further comprises a Z-height of the substrate.
7. The method of claim 1 , wherein the first set of coordinate data further comprises the actual location of one or more mini-marks formed on the substrate, wherein the one or more mini-marks are distinguishable from the one or more global alignment marks in size, shape, or both size and shape.
8. The method of claim 7 , wherein at least a portion of the one or more mini-marks is positioned between adjacent packages of the one or more packages.
9. The method of claim 1 , wherein scanning the substrate with the at least one scanning device to obtain the first set of coordinate data comprises capturing images of the one or more global alignment marks and the die marks.
10. The method of claim 9 , wherein capturing images of the one or more global alignment marks and the die marks comprises:
moving a lens of the at least one scanning device vertically to adjust a focus of the lens on the substrate; and
providing illumination to the substrate via one or more LEDs and an illuminator, wherein the images are captured at different focuses by moving the lens vertically.
11. A method for processing a substrate, comprising:
loading a substrate onto a stage of an inline metrology system, wherein the substrate comprises:
one or more packages comprising one or more die having die marks formed on the one or more die;
global alignment marks formed on the substrate; and
one or more calibration marks formed on the substrate;
capturing images of the global alignment marks using at least one scanning device associated with the inline metrology system to establish a metrology coordinate system of the substrate;
capturing images of the die marks using the at least one scanning device;
determining a position of the die marks relative to the metrology coordinate system established by the global alignment marks;
comparing the position of the global alignment marks and the die marks with a design file to obtain correction data;
transferring the substrate onto a stage of a digital lithography system;
determining a position of the global alignment marks using at least one scanning device associated with the digital lithography system to determine positioning of the substrate; and
patterning subsequent layers onto the substrate using a digital correction mask and at least one image projection system, wherein the digital correction mask is based, at least in part on the correction data.
12. The method of claim 11 , wherein the global alignment marks have a width in a range from about 50 microns to about 1000 microns.
13. The method of claim 12 , wherein the die marks have a width of 50 microns or less.
14. The method of claim 12 , wherein patterning subsequent layers comprises forming connections between adjacent die of the one or more die.
15. The method of claim 11 , wherein capturing images of the global alignment marks and capturing images of the die marks comprises:
moving a lens of the at least one scanning device vertically to adjust a focus of the lens on the substrate; and
providing illumination to the substrate via one or more LEDs and an illuminator, wherein the images are captured at different focuses by moving the lens vertically.
16. The method of claim 11 , further comprising capturing images of one or more mini-marks formed on the substrate using the at least one scanning device, wherein the one or more mini-marks are distinguishable from the global alignment marks in size, shape, or both size and shape.
17. The method of claim 16 , wherein at least a portion of the one or more mini-marks is positioned between adjacent packages of the one or more packages.