Feedforward and feedback control for conditioning of chemical mechanical polishing pad

• US 20060009129A1
• Filed: 09/06/2005
• Published: 01/12/2006
• Est. Priority Date: 06/19/2001
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Paik, Young Joseph
• Granted Patent: US 7,413,986 B2
• Time in Patent Office: Days
• US Class Current: 451/5
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• CPC Class Codes: B24B 37/042 operating processes therefor
• CPC Class Codes: B24B 49/03 according to the final size of the previously ground workpiece
• CPC Class Codes: B24B 49/18 taking regard of the presence of dressing tools
• CPC Class Codes: B24B 53/017 Devices or means for dressing, cleaning or otherwise conditioning lapping tools
• CPC Class Codes: G05B 19/00 Programme-control systems
• CPC Class Codes: G05B 19/19 characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path
• CPC Class Codes: G05B 19/41865 characterised by job scheduling, process planning, material flow
• CPC Class Codes: G05B 2219/32053 Adjust work parameter as function of other cell
• CPC Class Codes: G05B 2219/32065 Synchronise set points of processes
• CPC Class Codes: G05B 2219/45031 Manufacturing semiconductor wafers
• CPC Class Codes: H01L 21/31053 involving a dielectric removal step
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring
• CPC Class Codes: H01L 21/67276 Production flow monitoring, e.g. for increasing throughput program-control systems per se G05B19/00, e.g. total factory control G05B19/418
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps
• CPC Class Codes: Y02P 80/40 Minimising material used in manufacturing processes
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A method, apparatus and medium of conditioning a planarizing surface includes installing a wafer to be polished in a chemical mechanical polishing (CMP) apparatus having a polishing pad and a conditioning disk, polishing the wafer under a first set of pad conditioning parameters selected to maintain wafer material removal rates with preselected minimum and maximum removal rates, determining a wafer material removal rate occurring during the polishing step, calculating updated pad conditioning parameters to maintain wafer material removal rates within the maximum and minimum removal rates, and conditioning the polishing pad using the updated pad conditioning parameters, wherein the updated pad conditioning parameters are calculated using a pad wear and conditioning model that predicts the wafer material removal rate of the polishing pad based upon pad conditioning parameters, such as the conditioning down force and rotational speed of the conditioning disk.

Claims

1. An apparatus for conditioning polishing pads used to planarize substrates by the removal of material therefrom, comprising:

a carrier assembly having an arm positionable over a planarizing surface of a polishing pad;

a conditioning disk attached to the carrier assembly;

and an actuator capable of controlling an operating parameter of the conditioning disk;

a controller operatively coupled to the actuator, the controller operating the actuator to adjust the operating parameter of the conditioning disk as a function of a pad wear and conditioning model, the model defining a wafer material removal rate as a function of pad conditioning operating parameters, said operating parameters having minimum and maximum values.

2. The apparatus of claim 1, wherein the conditioning parameters comprise conditioning down force.

3. The apparatus of claim 2, wherein the conditioning parameters comprise rotational velocity of the conditioning disk.

4. The apparatus of claim 2, wherein the conditioning parameters comprise one or more parameters selected from the group consisting of rotational velocity of the disk, frequency of conditioning, duration of conditioning and translational speed of the conditioning disk.

5. The apparatus of claim 1, wherein the wafer material removal rate is determined according to the equation:

ŷ

<sub>i=ρ

i</sub>x_i+I_i,

where ŷ

_i is the wafer material removal rate for a conditioning parameter x_i, ρ

_ii, is the slope and I_i is the intercept of the curve of the defining the relationship between ŷ

_i and x_i.

6. The apparatus of claim 5, wherein the updated pad conditioning parameter, x_i+, is determined by solving the equation:

7. The apparatus of claim 1, wherein the controller comprises instructions for calculating adjusted operating parameters such that the updated operating parameter is within the maximum and minimum values.

8. The apparatus of claim 1, wherein the adjusted operating parameter is determined according to the equation k=(k₁)+g*(k−

(k₁)), where k is a measured wafer material removal rate, k−

1 is a calculated wafer material removal rate, g is the estimate gain, and (k−

(k₁)) is the prediction error.

9. The apparatus of claim 8, wherein the adjusted operating parameter is calculated by determining the difference between an output of the pad wear and conditioning model and a measured wafer material removal rate.

10. A computer readable medium comprising instructions being executed by a computer, the instructions including a computer-implemented software application for a chemical mechanical polishing process, the instructions for implementing the process comprising the steps of:

a) receiving data from a chemical mechanical polishing tool relating to the wafer removal rate of at least one wafer processed in the chemical mechanical polishing process; and

b) calculating, from the data of step (a), updated pad conditioning parameters within defined maximum and minimum values, wherein the updated pad conditioning parameters are calculated by determining the difference between an output of a pad wear and conditioning model that defines a wafer material removal rate as a function of at least one pad conditioning parameter having maximum and minimum values and the data of step (a).

11. The computer readable medium of claim 10, wherein the conditioning parameters comprise conditioning down force.

12. The computer readable medium of claim 11, wherein the conditioning parameters comprise rotational velocity of the conditioning disk.

13. The computer readable medium of claim 11, wherein the conditioning parameters comprise one or more parameters selected from the group consisting of rotational velocity of the disk, frequency of conditioning, duration of conditioning and translational speed of the conditioning disk.

14. The computer readable medium of claim 10, wherein said difference is adjusted using an estimate gain prior to calculating updated conditioning parameters.

15. The computer readable medium of claim 10, wherein the updated pad conditioning parameters are updated according to the equation k=(k₁)+g*(k−

(k₁)), where k is a measured wafer material removal rate, k₁ is a calculated wafer material removal rate, g is the estimate gain, and (k−

(k₁)) is the prediction error.

16. The computer readable medium of claim 10, wherein pad life is defined according to the equation:

PadLife=f(F_disk, ω

_disk, t_conditioning, f, T₂),

where F_disk is the down force applied by the conditioning disk to the CMP pad during conditioning, ω

_disk is the angular velocity of the conditioning disk during conditioning of the polishing pad, t is the time of conditioning, f is the frequency of condition and T₂ is the sweeping speed of the conditioning disk during conditioning.

17. The computer readable medium of claim 10, wherein the wafer material removal rate is defined by the equation

RemovalRate]^max_min=f(F_disk]^max_min,ω

_disk]^max_min,f]^max_min,t_conditioning]^max_minT₂]^max_min),

where F_disk is the down force applied by the conditioning disk to the CMP pad during conditioning, ω

_disk is the angular velocity of the conditioning disk during conditioning of the polishing pad, t is the time of conditioning, f is the frequency of condition, and T₂ is the sweeping speed of the conditioning disk during conditioning.

18. The computer readable medium of claim 10, wherein the wafer material removal rate is determined according to the equation:

ŷ

_i=ρ

_ix_i+I_i,

where ŷ

_i is the wafer material removal rate for a conditioning parameter x_i, ρ

_i is the slope and I_i is the intercept of the curve of the defining the relationship between ŷ

_i and x_i.

19. The computer readable medium of claim 19, wherein the updated pad conditioning parameter, x_i+, is determined by solving the equation: