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1. WO2002037085 - PROCESS CONTROL METHODS FOR USE WITH E-BEAM FABRICATION TECHNOLOGY

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

What is claimed is:

1. A method of process control for e-beam fabrication of a workpiece, said method including the steps of:
(a) impinging a surface of the workpiece with a e-beam during a manufacturing step in the manufacture thereof, and
(b) optically sensing the workpiece using thermal- wave imaging and/or ultrasound imaging techniques for process control,
wherein the e-beam impinging the workpiece in accordance with step (a) above provides substantially all the energy needed to be added to the workpiece to perform the optical sensing of step (b) above.

2. The method of claim 1 wherein the e-beam causes an exothermic chemical reaction to occur in the workpiece, which exothermic reaction generates energy, which contributes, in turn, to the energy needed to be added to the workpiece to perform the optical sensing of step (b) above.

3. The method of claims 1 or 2 wherein the e-beam comprises pulses of energy having a duration on the order of 10 nsec per pulse, an energy between 100 mj/cm2 and 100 J/cm2 and a spot size diameter at a surface of the workpiece of 1 to 10 mm.

4. The method of any one of claims 1 - 3 wherein the e-beam is controlled by a feedback loop based on data obtained during step (b) above.

5. The method of claim 4 wherein the optically sensing step (b) includes sensing infrared light emanating from the surface of the workpiece.

6. The method of claim 4 wherein the optically sensing step (b) includes:
(bl) illuminating at least a portion of the surface of the workpiece with a low power laser beam, the low power laser beam having a power output significantly less than the power of the e-beam; and
(b2) sensing reflected laser light from the surface of the workpiece.

7. The method of any one of claims 1 -6 wherein the step (b) of simultaneously optically sensing the workpiece occurs at a surface related to said workpiece.

8. The method of claim 7 wherein the related surface is the surface of a support structure which is transmissive of energy at a surface of the workpiece.

9. An apparatus for e-beam fabrication of a workpiece, said apparatus including:
an e-beam generator for generating an e-beam;
a direction control apparatus for directing the e-beam to impinge a surface of the workpiece with the e-beam;
an optical sensor for simultaneously optically sensing the workpiece; and
a feedback loop for controllably coupling the optical sensor to to e-beam generator and to the direction control apparatus for affecting where on the surface of the workpiece that the e-beam is directed,
wherein the e-beam impinging the workpiece provides substantially all the energy needed to be added to the workpiece to perform the optical sensing by the optical sensor.

10. The apparatus of claim 9 wherein the e-beam causes an exothermic chemical reaction to occur in the workpiece, which exothermic reaction generates energy which contributes to the energy needed to be added to the workpiece to perform the optical sensing by the optical sensor.

11. The apparatus of claims 9 or 10 wherein the e-beam generator generates pulses of energy having a duration on the order of 10 nsec per pulse, an energy between 100 mj/cm2 and 100 J/cm2 and a spot size diameter at a surface of the workpiece of 1 to 10 mm.

12. The apparatus of any one of claims 9 - 11 wherein the optical sensor includes a camera for sensing infrared light emanating from the surface of the workpiece.

13. The apparatus of any one of claims 9 - 12 wherein the optical sensor includes:
a low power laser for illuminating at least a portion of the surface of the workpiece with a low power laser beam, the low power laser beam having a power output significantly less than the power of the e-beam; and
a receiver for sensing laser light reflected from the surface of the workpiece.

14. The apparatus of claim 13 wherein the workpiece is supported by a support surface which is transmissive of optical energy having a wavelength of the laser beam emitted by said low power laser.

15. An apparatus for e-beam fabrication of a workpiece, said apparatus including:
an e-beam generator for generating an e-beam;
a direction control apparatus for directing the e-beam to impinge a surface of the workpiece with the e-beam;
an optical sensor for simultaneously optically sensing the workpiece, the optical sensor including (i) a low power laser for illuminating at least a portion of the surface of the workpiece with a low power laser beam or of a surface associated with the workpiece, the low power laser beam having a power output significantly less than the power of the e-beam and (ii) a receiver for sensing laser light reflected from the surface of the workpiece;
wherein the e-beam impinging the workpiece provides substantially all the energy needed to be added to the workpiece to perform the optical sensing by the optical sensor.

16. The apparatus of claim 15 wherein the workpiece is supported by a support surface which is transmissive of sonic energy, said support surface being associated with said workpiece for the transmission of sonic energy for detection by the receiver detecting the laser beam emitted by said low power laser, illuminating said support surface and reflected therefrom.