Method and system for measuring critical dimension and monitoring fabrication uniformity
A method for measuring critical dimension (CD) includes steps of: scanning at least one area of interest of a die to obtain at least one scanned image; aligning the scanned image to at least one designed layout pattern to identify a plurality of borders within the scanned image; and averaging distances each measured from the border or the plurality of borders of a pattern associated with a specific type of CD corresponding to the designed layout pattern to obtain a value of CD of the die. The value of critical dimensions of dies can be obtained from the scanned image with lower resolution which is obtained by relatively higher scanning speed, so the above-mentioned method can obtain value of CD for every die within entire wafer to monitor the uniformity of the semiconductor manufacturing process within an acceptable inspection time.
1. A method for monitoring fabrication uniformity, comprising steps of:
scanning at least one area of interest of a wafer to obtain at least one scanned image;
aligning the scanned image to at least one designed layout pattern to identify a plurality of borders within the scanned image; and
averaging distances each measured from the border or the plurality of borders of a pattern associated with a specific type of critical dimension corresponding to the designed layout pattern to obtain the value of critical dimension for every die of the entire wafer.
2. A method for monitoring fabrication uniformity according to claim 1 , wherein the scanned image is obtained by using an E-beam inspection tool to scan a surface of the wafer.
3. A method for monitoring fabrication uniformity according to claim 1 , wherein the designed layout pattern comprises a Graphic Data System (GDS) or an Open Artwork System Interchange Standard (OASIS), or is drawn on the scanned image directly.
4. A method for monitoring fabrication uniformity according to claim 1 , wherein the borders comprise a plurality of border-pixels within a peripheral region of the scanned image, wherein the peripheral region is close to the designed layout pattern and comprises a plurality of pixels of which gray level is greater than a reference value, and the border-pixel is a specific pixel of which gray level is a peak, averaged value of gray level of the pixels or the reference value within the peripheral region, or a pixel shifted a predetermined value from the border-pixel.
5. A method for monitoring fabrication uniformity according to claim 1 , wherein the area of interest comprises various types of critical dimension to be measured.
6. A method for monitoring fabrication uniformity according to claim 1 , wherein the type of critical dimension is determined by the corresponding operator of the type.
7. A method for monitoring fabrication uniformity according to claim 1 , wherein the type of critical dimension comprises line width, line spacing, corner width of trace, short axis width of conductive contact, long axis width of conductive contact, diameter of conductive contact, spacing between conductive contacts, or spacing between trace and conductive contact.
8. A non-transitory computer readable medium encoded with a computer program implementing a method for monitoring fabrication uniformity, wherein the method comprises steps of:
scanning at least one area of interest of a wafer to obtain at least one scanned image;
aligning the scanned image to at least one designed layout pattern to identify a plurality of borders within the scanned image; and
averaging distances each measured from the border or the plurality of borders of a pattern associated with a specific type of critical dimension corresponding to the designed layout pattern to obtain the value of critical dimension for every die of the entire wafer.
9. The non-transitory computer readable medium according to claim 8 , wherein the scanned image is obtained by using an E-beam inspection tool to scan a surface of the wafer.
10. The non-transitory computer readable medium according to claim 8 , wherein the designed layout pattern comprises a Graphic Data System (GDS) or an Open Artwork System Interchange Standard (OASIS), or is drawn on the scanned image directly.
11. The non-transitory computer readable medium according to claim 8 , wherein the borders comprise a plurality of border-pixels within a peripheral region of the scanned image, wherein the peripheral region is close to the designed layout pattern and comprises a plurality of pixels of which gray level is greater than a reference value, and the border-pixel is a specific pixel of which gray level is a peak, averaged value of gray level of the pixels or the reference value within the peripheral region, or a pixel shifted a predetermined value from the border-pixel.
12. The non-transitory computer readable medium according to claim 8 , wherein the area of interest comprises various types of critical dimension to be measured.
13. The non-transitory computer readable medium according to claim 8 , wherein the type of critical dimension is determined by the corresponding operator of the type.
14. The non-transitory computer readable medium according to claim 8 , wherein the type of critical dimension comprises line width, line spacing, corner width of trace, short axis width of conductive contact, long axis width of conductive contact, diameter of conductive contact, spacing between conductive contacts, or spacing between trace and conductive contact.