Exposure system and method

• US 7,301,603 B2
• Filed: 06/24/2004
• Issued: 11/27/2007
• Est. Priority Date: 06/24/2004
• Status: Expired due to Fees

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Chang, Yung-Chih, Hu, Chun-Ming, Chen, Kai-Hsiung
• Primary Examiner(s): Kim; Peter B.
• Application Number:
  US10/876,104
• Publication Number:
  US 20060008715A1
• Time in Patent Office: 1,251 Days
• Field of Search: 355/53, 355/72, 355/75, 355/77, 430/30, 430/22, 356/399, 356/400, 356/401, 700/114
• US Class Current: 355/53
• CPC Class Codes: G03F 7/70633 Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching

Abstract

An exposure system and method for use in an exposure tool. The system includes a compensation unit and an exposure unit. The compensation unit receives a fine-tuning value for an overlay correction parameter for a product in a first run. The compensation unit further receives an adjustment period for an exposure tool, an adjustment time for the exposure tool, and a process time for the product in a second run. The compensation unit also receives an equipment baseline offset of the exposure tool after adjustment, and compensates the fine-tuning value for the overlay correction parameter for the product accordingly. The exposure tool performs overlay processes on a wafer according to the compensated fine-tuning value for the overlay correction parameter.

Claims

1. An exposure system, comprising:

a compensation unit configured to;

receive a fine-tuning value for an overlay correction parameter for a product in a first run;

receive an adjustment period for an exposure tool;

receive an adjustment time for the exposure tool;

receive a process time for the product in a second run, the second run being subsequent to the first run;

receive an equipment baseline offset of the exposure tool after adjustment; and

compensate the fine-tuning value for the overlay correction parameter for the product according to;

the original fine-tuning value;

the equipment baseline offset;

the adjustment period;

the adjustment time; and

the process time; and

an exposure unit configured to perform overlay processes on a wafer according to the compensated fine-tuning value for the overlay correction parameter.

2. The exposure system of claim 1, wherein the compensation unit compensates the fine-tuning value according to:

CET′

(F_n-1)=CET(F_n-1)−

Δ

E_c;

wherein CET′

(F_n-1) is the compensated fine-tuning value;

wherein CET(F_n-1) is the fine-tuning value in the first run;

wherein

$\mathrm{\Delta <br><br>}<br><br><br><br>E_c=\mathrm{\Delta <br><br>}<br><br><br><br>\mathrm{MS}\times <br><br>\frac{T<br><br>\left(\mathrm{CET}<br><br>\left(F_{n-1}\right)\right)-T<br><br>\left({\mathrm{PM}}_{i-1}\right)}{T<br><br>\left(\mathrm{period}\right)};<br><br>$

wherein Δ

MS is the equipment baseline offset;

wherein T(CET(F_n-1)) is the process time for the product in the second run;

wherein T(PM_i-1) is the adjustment time for the exposure tool in a first preventative maintenance; and

wherein T(period) is the adjustment period for the exposure tool.

3. The exposure system of claim 1, wherein the compensation unit further compensates the fine-tuning value according to an adjustment of a pre-step'"'"'s equipment tool preceding the exposure tool in processing order.

4. The exposure system of claim 3, wherein the compensation unit compensates the fine-tuning value as a function of:

a fine-tuning value for the overlay correction parameter for the product in the second run on the pre-step'"'"'s equipment tool;

the equipment baseline offset;

the adjustment period;

an adjustment time for the pre-step'"'"'s equipment tool; and

a process time for the product in the second run on the pre-step'"'"'s equipment tool.

5. The exposure system of claim 4, wherein the compensation unit compensates the fine-tuning value according to:

PET(F_n-1)−

Δ

E_p;

wherein PET(F_n-1) is the fine-tuning value in the second run on the pre-step'"'"'s equipment tool;

wherein

$\mathrm{\Delta <br><br>}<br><br><br><br>E_p=\mathrm{\Delta <br><br>}<br><br><br><br>\mathrm{MS}\times <br><br>\frac{T<br><br>\left(\mathrm{PET}<br><br>\left(F_{n-1}\right)\right)-T<br><br>\left({\mathrm{PM}}_{j-1}\right)}{T<br><br>\left(\mathrm{period}\right)},$

wherein Δ

MS is the equipment baseline offset;

wherein T(PET(F_n-1)) is the process time for the product in the second run on the pre-step equipment tool;

wherein T(PM_j-1) is the adjustment time for the pre-step equipment tool; and

wherein T(period) is the adjustment period for the exposure tool.

6. The exposure system of claim 1, wherein the compensation unit further compensates the fine-tuning value according to a summation of the offset between compensated fine-tuning values in prior adjustments.

7. An exposure method, comprising the steps of:

receiving a fine-tuning value for an overlay correction parameter for a product in a first run;

receiving an adjustment period for an exposure tool;

receiving an adjustment time for the exposure tool;

receiving a process time for the product in a second run, the second run being subsequent to the first run;

receiving an equipment baseline offset of the exposure tool after adjustment;

compensating the fine-tuning value for the overlay correction parameter for the product according to;

the original fine-tuning value;

the equipment baseline offset;

the adjustment period;

the adjustment time; and

the process time; and

performing overlay processes on a wafer according to the compensated fine-tuning value for the overlay correction parameter.

8. The exposure method of claim 7, further comprising the step of compensating the fine-tuning value according to:

CET′

(F_n-1)=CET(F_n-1)−

Δ

E_c;

wherein CET′

(F_n-1) is the compensated fine-tuning value;

wherein CET(F_n-1) is the fine-tuning value in the first run;

wherein

$\mathrm{\Delta <br><br>}<br><br><br><br>E_c=\mathrm{\Delta <br><br>}<br><br><br><br>\mathrm{MS}\times <br><br>\frac{T<br><br>\left(\mathrm{CET}<br><br>\left(F_{n-1}\right)\right)-T<br><br>\left({\mathrm{PM}}_{i-1}\right)}{T<br><br>\left(\mathrm{period}\right)};<br><br>$

wherein Δ

MS is the equipment baseline offset;

wherein T(CET(F_n-1)) is the process time for the product in the second run;

wherein T(PM_i-1) is the adjustment time for the exposure tool in a first preventative maintenance; and

wherein T(period) is the adjustment period for the exposure tool.

9. The exposure method of claim 7, further comprising the step of compensating the fine-tuning value according to an adjustment of a pre-step'"'"'s equipment tool preceding the exposure tool in processing order.

10. The exposure method of claim 9, further comprising the step of compensating the fine-tuning value as a function of:

a fine-tuning value for the overlay correction parameter for the product in the second run on the pre-step'"'"'s equipment tool;

the equipment baseline offset;

the adjustment period;

an adjustment time for the pre-step'"'"'s equipment tool; and

a process time for the product in the second run on the pre-step'"'"'s equipment tool.

11. The exposure method of claim 10, further comprising the step of compensating the fine-tuning value according to:

PET(F_n-1)−

Δ

E_p;

wherein PET(F_n-1) is the fine-tuning value in the second run on the pre-step'"'"'s equipment tool;

wherein

$\mathrm{\Delta <br><br>}<br><br><br><br>E_p=\mathrm{\Delta <br><br>}<br><br><br><br>\mathrm{MS}\times <br><br>\frac{T<br><br>\left(\mathrm{PET}<br><br>\left(F_{n-1}\right)\right)-T<br><br>\left({\mathrm{PM}}_{j-1}\right)}{T<br><br>\left(\mathrm{period}\right)},$

wherein Δ

MS is the equipment baseline offset;

wherein T(PET(F_n-1)) is the process time for the product in the second run on the pre-step equipment tool;

wherein T(PM_j-1) is the adjustment time for the pre-step equipment tool; and

wherein T(period) is the adjustment period for the exposure tool.

12. The exposure method of claim 7, further comprising the step of compensating the fine-tuning value according to a summation of the offset between compensated fine-tuning values in prior adjustments.

13. A machine-readable storage medium storing a computer program which, when executed, directs a computer to perform a method comprising the steps of:

receiving a fine-tuning value for an overlay correction parameter for a product in a first run;

receiving an adjustment period for an exposure tool;

receiving an adjustment time for the exposure tool;

receiving a process time for the product in a second run, the second run being subsequent to the first run;

receiving an equipment baseline offset of the exposure tool after adjustment;

compensating the fine-tuning value for the overlay correction parameter for the product according to;

the original fine-tuning value;

the equipment baseline offset;

the adjustment period;

the adjustment time; and

the process time; and

performing overlay processes on a wafer according to the compensated fine-tuning value for the overlay correction parameter.

14. The storage medium of claim 13, wherein the method further comprises the step of compensating the fine-tuning value according to:

CET′

(F_n-1)=CET(F_n-1)−

Δ

E_c;

wherein T′

(F_n-1) is the compensated fine-tuning value;

wherein CET(F_n-1) is the fine-tuning value in the first run;

wherein

$\mathrm{\Delta <br><br>}<br><br><br><br>E_c=\mathrm{\Delta <br><br>}<br><br><br><br>\mathrm{MS}\times <br><br>\frac{T<br><br>\left(\mathrm{CET}<br><br>\left(F_{n-1}\right)\right)-T<br><br>\left({\mathrm{PM}}_{i-1}\right)}{T<br><br>\left(\mathrm{period}\right)};<br><br>$

wherein Δ

MS is the equipment baseline offset;

wherein T(CET(F_n-1)) is the process time for the product in the second run;

wherein T(PM_i-1) is the adjustment time for the exposure tool in a first preventative maintenance; and

wherein T(period) is the adjustment period for the exposure tool.

15. The storage medium of claim 13, wherein the method further comprises the step of compensating the fine-tuning value according to an adjustment of a pre-step'"'"'s equipment tool preceding the exposure tool in processing order.

16. The storage medium of claim 15, wherein the method further comprises the step of compensating the fine-tuning value as a function of:

a fine-tuning value for the overlay correction parameter for the product in the second run on the pre-step'"'"'s equipment tool;

the equipment baseline offset;

the adjustment period;

an adjustment time for the pre-step'"'"'s equipment tool; and

a process time for the product in the second run on the pre-step'"'"'s equipment tool.

17. The storage medium of claim 16, wherein the method further comprises the step of compensating the fine-tuning value according to:

PET(F_n-1)−

Δ

E_p;

wherein PET(F_n-1) is the fine-tuning value in the second run on the pre-step'"'"'s equipment tool;

wherein

$\mathrm{\Delta <br><br>}<br><br><br><br>E_p=\mathrm{\Delta <br><br>}<br><br><br><br>\mathrm{MS}\times <br><br>\frac{T<br><br>\left(\mathrm{PET}<br><br>\left(F_{n-1}\right)\right)-T<br><br>\left({\mathrm{PM}}_{j-1}\right)}{T<br><br>\left(\mathrm{period}\right)},$

wherein Δ

MS is the equipment baseline offset;

wherein T(PET(F_n-1)) is the process time for the product in the second run on the pre-step equipment tool;

wherein T(PM_j-1) is the adjustment time for the pre-step equipment tool; and

wherein T(period) is the adjustment period for the exposure tool.

18. The storage medium of claim 13, wherein the method further comprises the step of compensating the fine-tuning value according to a summation of the offset between compensated fine-tuning values in prior adjustments.

19. In a semiconductor manufacturing process with a first run and a second run, a method comprising the steps of:

receiving a fine-tuning value, CET(F_n-1), for the first run;

receiving an equipment baseline offset, Δ

MS;

receiving a process time, T(CET(F_n-1)), for the second run;

receiving an adjustment time, T(PM_i-1), for a first preventative maintenance of an exposure tool;

receiving an adjustment period, T(period), for the exposure tool;

compensating the fine-tuning value according to

${\mathrm{CET}}^{\mathrm{\prime <br><br>}}<br><br>\left(F_{n-1}\right)=\mathrm{CET}<br><br>\left(F_{n-1}\right)-\left(\mathrm{\Delta <br><br>}<br><br><br><br>\mathrm{MS}\times <br><br>\frac{T<br><br>\left(\mathrm{CET}<br><br>\left(F_{n-1}\right)\right)-T<br><br>\left({\mathrm{PM}}_{i-1}\right)}{T<br><br>\left(\mathrm{period}\right)}\right).$

20. The method of claim 19, further comprising the steps of:

receiving a fine-tuning value, PET(F_n-1), for the second run on a pre-step'"'"'s equipment tool preceding the exposure tool in processing order;

receiving a process time, T(PET(F_n-1)), for the second run on the pre-step'"'"'s equipment tool;

receiving an adjustment time, T(PM_j-1), for the pre-step'"'"'s equipment tool; and

compensating the fine-tuning value for the second run on the pre-step'"'"'s equipment tool according to

$\mathrm{PET}<br><br>\left(F_{n-1}\right)-\left(\mathrm{\Delta <br><br>}<br><br><br><br>\mathrm{MS}\times <br><br>\frac{T<br><br>\left(\mathrm{PET}<br><br>\left(F_{n-1}\right)\right)-T<br><br>\left({\mathrm{PM}}_{j-1}\right)}{T<br><br>\left(\mathrm{period}\right)}\right).$

21. In a semiconductor manufacturing process with a first run and a second run, an apparatus comprising:

means for receiving a fine-tuning value, CET(F_n-1), for the first run;

means for receiving an equipment baseline offset, Δ

MS;

means for receiving a process time, T(CET(F_n-1)), for the second run;

means for receiving an adjustment time, T(PM_i-1), for a first preventative maintenance of an exposure tool;

means for receiving an adjustment period, T(period), for the exposure tool;

means for compensating the fine-tuning value according to

${\mathrm{CET}}^{\mathrm{\prime <br><br>}}<br><br>\left(F_{n-1}\right)=\mathrm{CET}<br><br>\left(F_{n-1}\right)-\left(\mathrm{\Delta <br><br>}<br><br><br><br>\mathrm{MS}\times <br><br>\frac{T<br><br>\left(\mathrm{CET}<br><br>\left(F_{n-1}\right)\right)-T<br><br>\left({\mathrm{PM}}_{i-1}\right)}{T<br><br>\left(\mathrm{period}\right)}\right).$

22. The apparatus of claim 21, further comprising:

means for receiving a fine-tuning value, PET(F_n-1), for the second run on a pre-step'"'"'s equipment tool preceding the exposure tool in processing order;

means for receiving a process time, T(PET(F_n-1)), for the second run on the pre-step'"'"'s equipment tool;

means for receiving an adjustment time, T(PM_j-1), for the pre-step'"'"'s equipment tool; and

means for compensating the fine-tuning value for the second run on the pre-step'"'"'s equipment tool according to

$\mathrm{PET}<br><br>\left(F_{n-1}\right)-\left(\mathrm{\Delta <br><br>}<br><br><br><br>\mathrm{MS}\times <br><br>\frac{T<br><br>\left(\mathrm{PET}<br><br>\left(F_{n-1}\right)\right)-T<br><br>\left({\mathrm{PM}}_{j-1}\right)}{T<br><br>\left(\mathrm{period}\right)}\right).$

23. In a semiconductor manufacturing process with a first run and a second run, a compensation unit configured to receive a fine-tuning value for the first run, the compensation unit further being configured to receive an equipment baseline offset, the compensation unit further being configured to receive a process time for the second run, the compensation unit further being configured to receive an adjustment time for the second run, the compensation unit further being configured to receive an adjustment period for an exposure tool, the compensation unit further being configured to compensate the fine-tuning value according to

${\mathrm{CET}}^{\prime }$

⁡

( F n - 1 ) = CET ⁡

( F n - 1 ) - ( Δ

⁢

⁢

MS ×

T ⁡

( CET ⁡

( F n - 1 ) ) - T ⁡

( PM i - 1 ) T ⁡

( period ) ) ;

wherein CET′

(F_n-1) is the compensated fine-tuning value;

wherein CET(F_n-1) is the fine-tuning value for the first run;

wherein Δ

MS is the equipment baseline offset;

wherein T(CET(F_n-1)) is the process time for the second run;

wherein T(PM_i-1) is the adjustment time for a first preventative maintenance of the exposure tool; and

wherein T(period) is the adjustment period for the exposure tool.