Laser ablation

• US 20070012665A1
• Filed: 07/12/2005
• Published: 01/18/2007
• Est. Priority Date: 07/12/2005
• Status: Abandoned Application

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: French, Michael, Nelson, Curt
• Application Number:
  US11/179,173
• Publication Number:
  US 20070012665A1
• Time in Patent Office: Days
• US Class Current: 219/121.690
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: B23K 2103/172 wherein at least one of the layers is non-metallic
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: H05K 2201/10151 Sensor
• CPC Class Codes: H05K 2203/163 Monitoring a manufacturing process
• CPC Class Codes: H05K 3/0038 combined with laser drilling through a metal layer

Abstract

Thermal characteristics of a layer being ablated by a laser are sensed and used to adjust ablation by the laser.

Claims

1. A method comprising:

ablating a first layer with a laser;

sensing a thermal characteristic of the first layer; and

adjusting ablation by the laser based upon the sensed thermal characteristic of the first layer.

2. The method of claim 1, wherein adjusting ablation by the laser comprises adjusting a fluence of the laser.

3. The method of claim 1, wherein adjusting ablation by the laser comprises adjusting a frequency of laser pulses of the laser.

4. The method of claim 1, wherein adjusting ablation by the laser comprises adjusting a speed at which the layer and the laser are moved relative to one another.

5. The method of claim 4, wherein adjusting a speed comprises adjusting a speed at which a galvanometer is moved.

6. The method of claim 4, wherein adjusting a speed comprises adjusting a speed at which the layer is moved.

7. The method of claim 1, wherein adjusting ablation by the laser comprises ending ablation by the laser.

8. The method of claim 1, wherein adjusting ablation by the laser comprises slowing a rate of ablation by the laser.

9. The method of claim 1 further comprising identifying an extent of an ablation based upon the sensed thermal characteristic.

10. The method of claim 1 wherein the sensed thermal characteristic is a time during which emitted radiation exceeds a predetermined level.

11. The method of claim 1 wherein the thermal characteristic is a peak value for emitted radiation.

12. The method of claim 1, wherein ablating the first layer includes masking the laser to ablate a pattern on the first layer.

13. The method of claim 1, further comprising deriving one or more equations defining a relationship between the sensed thermal characteristic and extent of ablation.

14. The method of claim 1, wherein the first layer is a polymeric layer.

15. The method of claim 1, wherein the first layer is a metal layer.

16. The method of claim 1, wherein the first layer is semiconductive.

17. The method of claim 1 further comprising:

ablating a second layer adjacent the first layer with the laser;

sensing a thermal characteristic of the second layer; and

adjusting ablation of the second layer by the laser based upon the sensed thermal characteristic of the second layer.

18. The method of claim 1, wherein the first layer is adjacent a second layer and wherein the layer further comprises:

identifying a junction of the first layer and the second layer based upon a sensed thermal characteristic of at least one of the first layer and the second layer.

19. The method of claim 18 further comprising adjusting ablation by the laser based upon the identification of the junction.

20. The method of claim 19, wherein adjusting ablation by the laser includes terminating ablation by the laser.

21. The method of claim 19, wherein adjusting ablation by the laser includes adjusting a rate of ablation by the laser.

22. The method of claim 19, wherein adjusting ablation by the laser includes adjusting a rate at which energy is applied to the second layer by the laser.

23. A system comprising:

a laser;

a sensor configured to sense thermal characteristics of a layer being ablated by the laser; and

a controller configured to generate control signals based upon a sensed thermal characteristic of the layer being ablated, wherein the laser adjusts its operation in response to the control signals.

24. The system of claim 23, wherein the control signals are configured such that the laser stops irradiating the layer in response to the control signals.

25. The system of claim 23, wherein the control signals are configured such that a rate at which the laser ablates the layer is adjusted in response to the control signals.

26. The system of claim 23, wherein the control signals are configured such that a rate at which the laser applies energy to the layer is adjusted in response to the control signals.

27. The system of claim 23, wherein the control signals are configured such that a fluence of the laser is adjusted in response to the control signals.

28. The system of claim 23, wherein the controller is further configured to identify an extent of an ablation based upon the sensed thermal characteristic.

29. The system of claim 23, further comprising:

a stage supporting the layer being ablated; and

an actuator configured to move the stage, wherein a rate at which the actuator moves the stage and the layer being ablated relative to the laser is adjusted in response to the control signals.

30. The system of claim 23, further comprising:

a galvanometer, wherein a rate at which the galvanometer moves is adjusted in response to the control signals.

31. The system of claim 23 further comprising a laser mask through which energy is patterned upon the layer being ablated.

32. A computer readable medium comprising:

instructions to ablate a layer with a laser;

instructions to sense a thermal characteristic of the layer; and

instructions to adjust the laser based upon the sensed thermal characteristic of the layer.

33. A method comprising:

a step for determining an ablation depth in a layer based upon thermal characteristics of the layer; and

a step for controlling a laser based upon the determined ablation extent.