Laser processing apparatus, method for laser processing a workpiece, and related configurations

Abstract

To provide an apparatus and techniques for more easily laser-processing workpieces.SOLUTION: Workpieces are processed in a manner of enhancing accuracy, and throughput, etc. Realtime Z-height measurement is performed and, when suitable, compensation for certain Z-height deviations is performed. Further, scan patterns, and beam characteristics, etc. are modulated to facilitate feature formation, avoid undesirable heat accumulation, or enhance processing throughput.SELECTED DRAWING: Figure 1

Claims

1. An apparatus for processing a workpiece comprising a first layer and a second layer formed from a material different from the first layer, to form features on the workpiece, Acousto-optic deflector (AOD) system capable of deflecting a beam path along which laser energy, including multiple laser pulses, propagates within a two-dimensional scan field along which the device can project onto the workpiece, A first AOD capable of deflecting the beam path along the first axis of the two-dimensional scan field, A second AOD is positioned optically downstream of the first AOD and is capable of deflecting the beam path along the second axis of the two-dimensional scan field. AOD system including, A controller that is communicatively connected to the AOD system, During the first processing step of forming the feature, the AOD system is controlled to deflect the beam path within the two-dimensional scan field to form an opening that penetrates the first layer and exposes the second layer by indirect ablation of the first layer. The indirect ablation of the first layer includes irradiating the first layer with laser energy to generate heat within the first layer, transferring the heat from the first layer to the second layer to evaporate a region of the second layer adjacent to the first layer, and ejecting a portion of the first layer due to the pressure generated by the evaporation of the region of the second layer. After the first processing step, during the second processing step of forming the feature, the AOD system is controlled to deflect the beam path within the two-dimensional scan field to irradiate the second layer with laser energy through the aperture, and to extend the aperture to at least a portion of the second layer. The AOD system is controlled to attenuate the laser energy more significantly during the second processing step compared to during the first processing step. A controller that allows A device equipped with the following features.

2. The apparatus according to claim 1, further comprising a laser source capable of generating the aforementioned laser energy.

3. The apparatus according to claim 1, wherein the laser energy has a wavelength in the ultraviolet (UV) region of the electromagnetic spectrum.

4. The apparatus according to claim 1, wherein the laser energy has a wavelength in the green light region of the electromagnetic spectrum.

5. The apparatus according to claim 1, wherein the laser energy is expressed as a series of laser pulses generated at a pulse repetition rate of 100 kHz or higher.

6. The apparatus according to claim 5, wherein the laser energy is expressed as a series of laser pulses generated at a pulse repetition rate of 300 kHz or higher.

7. The apparatus according to claim 6, wherein the laser energy is expressed as a series of laser pulses generated at a pulse repetition rate of 500 kHz or higher.

8. The apparatus according to claim 1, wherein the laser energy is expressed as a series of laser pulses having a pulse duration of less than 1 μs.

9. The apparatus according to claim 8, wherein the laser energy is expressed as a series of laser pulses having a pulse duration of less than 100 ns.

10. The apparatus according to claim 8, wherein the laser energy is expressed as a series of laser pulses having a pulse duration greater than 10 ns.

11. The apparatus according to claim 1, further comprising at least one galvanometer mirror system positioned optically downstream of the AOD system and capable of deflecting the two-dimensional scan field projectable onto the workpiece.

12. An acousto-optic deflector (AOD) system included in an apparatus for processing a workpiece comprising a first layer and a second layer formed from a different material than the first layer to form features on the workpiece, the AOD system being capable of deflecting a beam path along which laser energy can propagate within a two-dimensional scan field, the AOD system comprising a first AOD capable of deflecting the beam path along a first axis of the two-dimensional scan field, and a second AOD positioned optically downstream of the first AOD and capable of deflecting the beam path along a second axis of the two-dimensional scan field, the controller for the AOD system, At least one processor, Computer memory accessible by the at least one processor, when executed by the at least one processor, During the first processing step, the AOD system is controlled to deflect the beam path within the two-dimensional scan field to form an opening that penetrates the first layer and exposes the second layer by indirect ablation of the first layer. The indirect ablation of the first layer includes irradiating the first layer with laser energy to generate heat within the first layer, transferring the heat from the first layer to the second layer to evaporate a region of the second layer adjacent to the first layer, and ejecting a portion of the first layer due to the pressure generated by the evaporation of the region of the second layer. The beam path is deflected within the two-dimensional scan field to irradiate the second layer with the laser energy through the aperture, the AOD system is controlled during the second processing step after the first processing step to extend the aperture to at least a portion of the second layer, and the laser energy output from the AOD system during the second processing step is attenuated relative to the laser energy output from the AOD system during the first processing step. A computer memory containing an instruction that commands the controller to output at least one control signal to the AOD system, A controller, including...

13. Non-transient computer-readable medium, included in an apparatus for processing a workpiece comprising a first layer and a second layer formed of a different material from the first layer, to form features on the workpiece, an acousto-optic deflector (AOD) system capable of deflecting a beam path along which laser energy can propagate within a two-dimensional scan field, the non-transient computer-readable medium being used with a controller configured to control an AOD system having a first AOD capable of deflecting the beam path along a first axis of the two-dimensional scan field, and a second AOD positioned optically downstream of the first AOD and capable of deflecting the beam path along a second axis of the two-dimensional scan field, When executed by the aforementioned controller, At least one control signal is output to control the AOD system during the first processing step so as to deflect the beam path within the two-dimensional scan field and form an opening that penetrates the first layer and exposes the second layer by indirect ablation of the first layer, The indirect ablation of the first layer includes irradiating the first layer with laser energy to generate heat within the first layer, transferring the heat from the first layer to the second layer to evaporate a region of the second layer adjacent to the first layer, and ejecting a portion of the first layer due to the pressure generated by the evaporation of the region of the second layer. The AOD system is controlled during the second processing step after the first processing step to deflect the beam path within the two-dimensional scan field and irradiate the second layer with the laser energy through the aperture, extend the aperture to at least a portion of the second layer, and outputs at least one control signal configured to attenuate the laser energy output from the AOD system during the second processing step relative to the laser energy output from the AOD system during the first processing step. The system stores an instruction that commands the controller to output one or more control signals to control the AOD system. Non-transient computer-readable media.

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