US 12,142,535 B2
Method and apparatus to determine a patterning process parameter using a unit cell having geometric symmetry
Adriaan Johan Van Leest, Eindhoven (NL); Anagnostis Tsiatmas, Eindhoven (NL); Paul Christiaan Hinnen, Veldhoven (NL); Elliott Gerard McNamara, Eindhoven (NL); Alok Verma, Eindhoven (NL); Thomas Theeuwes, Veldhoven (NL); and Hugo Augustinus Joseph Cramer, Eindhoven (NL)
Assigned to ASML NETHERLANDS B.V., Veldhoven (NL)
Filed by ASML NETHERLANDS B.V., Veldhoven (NL)
Filed on Feb. 28, 2017, as Appl. No. 15/445,465.
Claims priority of provisional application 62/458,932, filed on Feb. 14, 2017.
Claims priority of provisional application 62/435,649, filed on Dec. 16, 2016.
Claims priority of provisional application 62/435,670, filed on Dec. 16, 2016.
Claims priority of provisional application 62/435,662, filed on Dec. 16, 2016.
Claims priority of provisional application 62/435,630, filed on Dec. 16, 2016.
Claims priority of provisional application 62/301,880, filed on Mar. 1, 2016.
Prior Publication US 2017/0256465 A1, Sep. 7, 2017
Int. Cl. G01N 21/95 (2006.01); G03F 7/00 (2006.01); G03F 9/00 (2006.01); H01L 21/66 (2006.01)
CPC H01L 22/12 (2013.01) [G01N 21/9501 (2013.01); G03F 7/70633 (2013.01); G03F 7/70683 (2013.01); G03F 9/7003 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A method comprising:
illuminating a substrate with a radiation beam such that a beam spot on the substrate is filled with one or more physical instances of a unit cell of the substrate, the unit cell having geometric symmetry at a nominal value of overlay;
detecting radiation redirected by the one or more physical instances of the unit cell using a detector of an optical measurement apparatus;
transforming electrical signals of the detected radiation, by a hardware computer system, into an overlay value by determining a non-nominal value of overlay of the unit cell from values of an optical characteristic of the detected radiation, the determining comprising assigning a different weighting to optical characteristic values from pixels of the detected radiation associated with greater sensitivity to overlay than to optical characteristic values from other pixels of the detected radiation associated with lower sensitivity to overlay; and
physically moving, based on the overlay value and by a semiconductor manufacturing apparatus, a semiconductor device pattern on the substrate or another substrate with respect to another pattern, or vice versa, to reduce overlay error.