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US 7,031,794 B2Granted
Smart overlay control
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsKun-Pi Cheng, Hsin-Yuan Chen, Yo-Nien Lin, Feng-Cheng Chung
Life of this patent
Estimating the term…
Abstract
An automatic method to maintain and correct overlay in the fabrication of integrated circuits is described. An overlay control table is automatically generated for lots run through a process tool. An overlay correction is calculated from the overlay control table and sent to the process tool for real-time or manual overlay correction.
Claims19
An overlay control system comprising:
- a plurality of process machines;
- a data collection tool wherein said data collection tool measures overlay error from a run of a lot through a process machine and generates overlay error measurement data;
- a data processing tool for processing said overlay error measurement data, said processing including generating an overlay control table wherein said overlay control table comprises current layer overlay correction value, Cn, previous layer overlay correction value, Pn, overlay measurement error value, On, residual overlay error value, Rn, fine tuning value, Fn, and average process offset value, K for a lot n, wherein the data processing tool sends the overlay control table to an operator for use in manual overlay correction or to a smart overlay control servo for use in automatic overlay correction;
- and
- an in-line equipment servo wherein said in-line equipment servo obtains previous layer correction and fine tuning values from said smart overlay control servo for a lot on a process machine, calculates an overlay correction using said previous layer overlay correction and said fine tuning values, and sends said overlay correction to said process machine,
- wherein for said lot n, the overlay control table is generated using the following algorithm:
- Cn = Pn + Fn−1
- On
- Rn
- n = 1
- C1 = P1 + K
- O1
- R1 = K − O1
- n = 2
- C2 = P2 + F1
- O2
- R2 = F1 − O2
- n = 3
- C3 = P3 + F2
- O3
- R3 = F2 − O3
- n = 4
- C4 = P4 + F3
- O4
- R4 = F3 − O4
- n = 5
- C5 = P5 + F4
- O5
- R5 = F4 − O5
- n = 6
- C6 = P6 + F5
- O6
- R6 = F5 − O6
- n = k
- Ck = Pk + Fk−1
- Ok
- Rk = Fk−1 − Ok
- n = k + 1
- Ck+1 = Pk+1 + Fk
- Ok+1
- Rk+1 = Fk − Ok+1
- Fn
- n = 1
- F1 = R1
- n = 2
- F2 = ½ * (R1 + R2)
- n = 3
- F3 = ⅓ * (R1 + R2 + R3)
- n = 4
- F4 = ⅓ * (R2 + R3 + R4)
- n = 5
- F5 = ⅓ * (R3 + R4 + R5)
- n = 6
- F6 = ⅓ * (R4 + R5 + R6)
- n = k
- Fk = ⅓ * (Rk−2 + Rk−1 + Rk)
- n = k + 1
- Fk+1 = ⅓ * (Rk−1 + Rk + Rk+1)
- wherein said variables Cn, Pn, On, Rn, Fn, and K are defined as above and P1=0 and K value is supplied with initial data for n=1.
56 more elements
A method of overlay control comprising:
- automatically generating an overlay control table for lots run through a process tool, wherein for a lot n, said overlay control table is generated using the following algorithm:
- Cn = Pn + Fn−1
- On
- Rn
- n = 1
- C1 = P1 + K
- O1
- R1 = K − O1
- n = 2
- C2 = P2 + F1
- O2
- R2 = F1 − O2
- n = 3
- C3 = P3 + F2
- O3
- R3 = F2 − O3
- n = 4
- C4 = P4 + F3
- O4
- R4 = F3 − O4
- n = 5
- C5 = P5 + F4
- O5
- R5 = F4 − O5
- n = 6
- C6 = P6 + F5
- O6
- R6 = F5 − O6
- n = k
- Ck = Pk + Fk−1
- Ok
- Rk = Fk−1 − Ok
- n = k + 1
- Ck+1 = Pk+1 + Fk
- Ok+1
- Rk+1 = Fk − Ok+1
- Fn
- n = 1
- F1 = R1
- n = 2
- F2 = ½ * (R1 + R2)
- n = 3
- F3 = ⅓ * (R1 + R2 + R3)
- n = 4
- F4 = ⅓ * (R2 + R3 + R4)
- n = 5
- F5 = ⅓ * (R3 + R4 + R5)
- n = 6
- F6 = ⅓ * (R4 + R5 + R6)
- n = k
- Fk = ⅓ * (Rk−2 + Rk−1 + Rk)
- n = k + 1
- Fk+1 = ⅓ * (Rk−1 + Rk + Rk+1)
- wherein Cn is current layer overlay correction value Pn is previous layer overlay correction value where P1=0, On is overlay measurement error value, Rn is residual overlay error value Fn is fine tuning value, and K is average process offset value where K is supplied with initial data for n=1;
- and
- sending an overlay correction calculated from said overlay control table to an in-line equipment servo for automatic overlay correction of said process tool in real-time.
53 more elements
A method of overlay control comprising:
- automatically generating an overlay control table for lots run through a process tool, wherein for a lot n, said overlay control table is generated using the following algorithm:
- Cn = Pn + Fn−1
- On
- Rn
- n = 1
- C1 = P1 + K
- O1
- R1 = K − O1
- n = 2
- C2 = P2 + F1
- O2
- R2 = F1 − O2
- n = 3
- C3 = P3 + F2
- O3
- R3 = F2 − O3
- n = 4
- C4 = P4 + F3
- O4
- R4 = F3 − O4
- n = 5
- C5 = P5 + F4
- O5
- R5 = F4 − O5
- n = 6
- C6 = P6 + F5
- O6
- R6 = F5 − O6
- n = k
- Ck = Pk + Fk−1
- Ok
- Rk = Fk−1 − Ok
- n = k + 1
- Ck+1 = Pk+1 + Fk
- Ok+1
- Rk+1 = Fk − Ok+1
- Fn
- n = 1
- F1 = R1
- n = 2
- F2 = ½ * (R1 + R2)
- n = 3
- F3 = ⅓ * (R1 + R2 + R3)
- n = 4
- F4 = ⅓ * (R2 + R3 + R4)
- n = 5
- F5 = ⅓ * (R3 + R4 + R5)
- n = 6
- F6 = ⅓ * (R4 + R5 + R6)
- n = k
- Fk = ⅓ * (Rk−2 + Rk−1 + Rk)
- n = k + 1
- Fk+1 = ⅓ * (Rk−1 + Rk + Rk+1)
- wherein Cn is current layer overlay correction value, Pn is previous layer overlay correction value where P1=0, On is overlay measurement error value, Rn is residual overlay error value, Fn is fine tuning value, and K is average process offset value where K is supplied with initial data for n=1;
- and
- sending an overlay correction calculated from said overlay control table to a lot information servo for manual overlay correction of said process tool.
53 more elements
Dependencies are inferred from the claim text.