TWI406806B - Method and apparatus for micromachining a material - Google Patents

Abstract

A method for micromachining a material, including configuring an optical system to provide illumination of an illumination wavelength to a site via a given element of the optical system, the illumination generating returning radiation from the site. The method further includes configuring the optical system to receive the returning radiation via the given element, and to form an image of the site therefrom, calculating an actual position of a location at the site from the image and outputting a signal indicative of the actual position of the location, generating a beam of micromachining radiation having a micromachining wavelength different from the illumination wavelength, positioning the beam to form an aligned beam with respect to the location in response to the signal, and conveying the aligned beam to the location via at least the given element of the optical system so as to perform a micromachining operation at the location.

Description

Method and apparatus for micromachining a material

Laser micromachining is especially useful for forming holes in printed circuit boards (PCBs). As the component size of the PCB shrinks, the requirements for the positioning and accuracy of laser processing continue to increase.

In an embodiment of the invention, there is provided a micromachining device for micromachining a location at a location, the portion typically comprising an object embedded in a circuit insulative substrate of a printed circuit board (PCB), such as a conductive solder pad. The apparatus includes an optical system that illuminates the portion with a source of radiation that receives return radiation from the portion as a function of illumination and transmits a micromachined beam from the source of the beam to the location. There is at least one common element in the optical system, such as a steerable mirror for all three functions. The source of radiation operates at a different wavelength than the beam source. The beam source is typically a laser. The source of radiation is typically a laser diode, although in some embodiments, the source of radiation may be a light emitting diode (LED).

An image sensor images the portion using return radiation, and a processor calculates an actual position of the location of the desired micromachining (eg, the center of the conductive pad) based on the image. The processor generates a signal indicative of the actual position and uses the signal to align the micromachined beam with respect to the position - typically by adjusting the steerable mirror. The processor then operates the beam source to micromachine the location using the aligned beam. The beam can be micromachined into a substantially arbitrary shape of the hole in the positioning. By using at least one common component for site illumination, site imaging, and beam transfer functions, the device is capable of providing local high intensity illumination to the site, thereby forming a good image of the site, and thus rapidly and accurately pairing the micromachined beam It is necessary to locate.

Typically, the device is used for micromachining in multiple locations in a PCB where each location has a different location. For each part, the processor can calculate the nominal coordinates of the positioning of the desired micromachining by, for example, analyzing a computer aided manufacturing (CAM) file of the circuit, and positioning the substrate using the nominal coordinates, thereby causing the portion to be Nominally aligned with the beam and illumination. At each location, the actual position of the beam is determined as described above. For at least some of the plurality of locations, the realignment of the beam between the various portions is performed by operating only the steerable mirror, thereby increasing the rate of micromachining of the PCB while maintaining the beam for all locations Exact alignment.

In one disclosed embodiment, the image sensor obtains a local image of the beam onto the location, typically by the processor having a low power below the ablation threshold of the portion. The beam source is operated to perform. The processor determines the offset to be applied to the beam based on the image of the portion and the localized image of the beam, thereby performing beam alignment as described above.

In some embodiments, the radiation source can generate fluorescent radiation as return radiation, and the image sensor forms an image of the portion and/or a calibration target based on the fluorescent radiation. The processor can typically adjust the wavelength and/or power of the radiation source based on the fluorescent characteristics of the portion. This adjustment can be implemented to cause radiation from the radiation source to penetrate the portion and/or the area surrounding the portion, thereby optimizing the image of the portion from the fluorescent radiation. The use of fluorescent radiation eliminates speckle problems if the source is a laser.

In an alternate embodiment of the invention, the radiation of the radiation source is linearly polarized and polarization analysis can be performed on the return radiation. For a portion containing the embedded conductive object, the return radiation from the object is typically at least partially depolarized due to the surface roughness of the object. Thus, the image sensor is capable of forming an image of a good contrast of the object relative to its surroundings, whose return radiation is typically not depolarized.

In still another alternative embodiment of the invention, the radiation source includes a laser that produces an associated beam of light having a short coherence length to substantially eliminate speckle effects. Alternatively, or in addition, the source of radiation includes other components for reducing and/or eliminating speckle, such as a plurality of fibers having different wavelengths of light.

In another disclosed embodiment, the source of radiation is used to illuminate the portion using structured illumination (e.g., by forming an object-centered ring at the location), and the substrate is diffusive. The combination of circular illumination and a diffusing substrate effectively "backlit" the object.

Thus, in accordance with an embodiment of the present invention, a method for micromachining a material is provided, comprising: configuring an optical system to provide an illumination of a portion of the material by a given component of the optical system a wavelength illumination that generates return radiation from the portion; the optical system configured to receive the return radiation by the given component and thereby form an image of the portion; and calculate a location at the location based on the image Actual position, and outputting a signal indicative of the actual position of the positioning; generating a micromachined radiation beam having a micromachining wavelength different from one of the illumination wavelengths; determining the position of the beam relative to the location in response to the signal, An alignment beam is formed; the alignment beam is delivered to the location via at least the given element of the optical system to perform a micromachining operation at the location.

Typically, the portion includes an object embedded in one or more of the insulative substrates, and providing illumination to the portion can include providing structured illumination that only illuminates an area surrounding the object. The structured illumination can be formed by a diffractive element.

In one embodiment, providing illumination to the portion includes selecting the illumination wavelength to be a wavelength that causes the portion to emit fluorescence, and the return radiation comprises fluorescent radiation generated at the portion in response to the provided illumination. The method can include filtering the fluorescent radiation to optimize the image of the portion.

In an alternate embodiment, providing illumination to the portion includes providing polarized illumination to the portion, and forming an image of the portion includes polarization analysis of return radiation from the portion.

In some embodiments, the given element includes a steerable mirror, the portion can include a plurality of different sub-portions in which micromachining is to be performed, and determining the position of the beam can include by only manipulating the mirror The beam is directed to the plurality of different sub-portions.

In yet another alternative embodiment, the given element includes a string of optical elements for focusing the beam and illumination to the location.

The location can include a location area, and providing illumination to the location can include providing illumination to the location area and to another area that is no greater than the location area and adjacent thereto. Typically, forming an image can include forming an image on an image sensor, and the illumination can have an intensity that produces an image on the image sensor in less than 3 milliseconds or less. Forming an image can include forming an image on an image sensor having a pixel array and selecting pixels from the array to analyze the image in response to the region and the other region.

The method also includes determining a nominal location of the location prior to providing illumination to the location and providing illumination in response to the nominal location.

In still another alternative embodiment, generating the micromachined radiation beam comprises: generating a low power beam having a power below an ablation threshold of the portion; transmitting the low power beam to the portion; The low power beam is imaged at one of the locations to determine an offset of the beam.

Typically, determining the position of the beam includes determining the position of the beam due to the amount of offset, and transmitting the beam of the determined position to the location includes setting the beam to have a power equal to or greater than one of the ablation thresholds .

The method can include configuring the illumination wavelength to have a value that renders the site non-absorbent.

In an alternate disclosed embodiment, the portion includes an outer surface, and providing illumination to the portion includes illuminating the portion with imaging radiation perpendicular to the outer surface.

Illuminating the portion can include providing coherent imaging radiation at the location, the coherent imaging radiation having a coherence length equal to or less than twice the size of the portion.

In yet another alternative disclosed embodiment, calculating the actual position comprises: providing a theoretical relationship based on the expected image of the portion; determining an actual relationship based on the image; and fitting the actual relationship to the theoretical relationship.

Forming the image of the portion can include adjusting at least one of an illumination wavelength and a power of illumination to change a penetration depth of the illumination at the location.

In one embodiment, the portion includes an object embedded in a diffusing layer, and the method includes compensating for a deviation caused by an image formed by an object embedded in the diffusing layer.

In accordance with an embodiment of the present invention, a method for micromachining a material is provided, comprising: operating a source to provide a radiation beam to a portion of the material that includes a location, the radiation beam being at a material Generating the operating wavelength of the fluorescent light, and is insufficient to micro-process one of the beam powers to generate fluorescent radiation from the portion; forming an image of the portion due to the fluorescent radiation; determining the image relative to the positioning Positioning the beam; and operating the source to provide the radiation beam to the location, the radiation beam being at the operating wavelength and at a micromachining power sufficient to facilitate micromachining of the location.

Typically, operating the source at the beam power comprises providing the radiation beam to the portion via a beam directing optical system, and forming the image includes transmitting the fluorescent radiation to an image sensing via at least one component of the beam directing optical system Device. The method can include filtering the fluorescent radiation to optimize the image of the portion.

According to an embodiment of the present invention, there is further provided an apparatus for micromachining a material, comprising: a radiation source for providing illumination to a portion of the material by a given component of an optical system a wavelength illumination that produces return radiation from the portion; an image sensor for receiving the return radiation by the given component and thereby forming an image of the portion; a beam source for Generating a micromachined radiation beam having a micromachining wavelength different from one of the illumination wavelengths; and a processor for calculating an actual position of the location at the location based on the image and outputting an indication a signal of the actual position of the position, the position of the beam is determined relative to the position of the signal to form an alignment beam, and the beam source is operated to transmit the alignment beam to at least the given element via the optical system The positioning is performed by performing a micromachining operation at the location.

The device can include a set of filters for filtering the fluorescent radiation, and the processor can be used to select one of the groups to optimize the image of the portion.

The illumination can include polarized illumination, and the device can include a polarizing element that enables the image sensor to perform polarization analysis of the return radiation from the portion.

The given element can include a steerable mirror.

Alternatively, the given element can include a string of optical elements for focusing the beam and illumination to the location.

According to an embodiment of the present invention, there is further provided an apparatus for micromachining a material, comprising: a beam source for providing a radiation beam to a portion of the material including a location, the radiation beam being The material emits one of the operating wavelengths of the fluorescent light and is insufficient for one of the beam powers for micromachining to generate fluorescent radiation from the positioning; an image sensor for forming the portion in response to the fluorescent radiation An image; and a processor for determining a position of the light beam with respect to the positioning in response to the image, and operating the beam source to provide the radiation beam to the positioning at the operating wavelength and a micromachining power, The micromachining power is sufficient to facilitate micromachining of the positioning.

The apparatus can include a beam directing optical system, and operating the beam source at the beam power can include providing the radiation beam to the portion by the beam directing optical system, and forming the image can include directing the optical system by the beam At least one component transmits the fluorescent radiation to the image sensor.

The device can include a set of filters for filtering the fluorescent radiation, and the processor can be used to select one of the groups to optimize the image of the portion.

The invention will be more fully understood from the following detailed description of embodiments of the invention.

Referring now to Figure 1, a schematic diagram of a beam alignment device 20 in accordance with one embodiment of the present invention. The device 20 is used to micromachine a portion 43, hereinafter, for example, assuming that the portion 43 is contained in a printed circuit board (PCB) 24. The portion 43 typically comprises an insulating substrate material (eg, epoxy with glass beads and/or fibers) and/or a conductive material (eg, a copper pad or trace). Typically, although not necessarily, the portion 43 comprises a conductive material embedded in an insulating substrate material. Device 20 includes a beam source 22 that projects a beam of radiation 26 via a collimator 27. Light beam 26 is used to micromachine a hole in the location in location 43. In one embodiment, source 22 includes an ultraviolet (UV) laser that operates at a beam wavelength of about 350 nm. The UV laser can operate as a short pulse laser that uses a nonlinear interaction of short pulses to cause ablation, the length of which is on the order of femtoseconds. In an alternate embodiment, source 22 includes a carbon dioxide laser that operates at a beam wavelength of about 10 microns. However, device 20 can use any suitable source of radiation that can be configured to provide the radiant energy that portion 43 can absorb, the form and level of which can be used for micromachining. In the following, as an example, it is assumed that the source 22 comprises a laser, and thus the beam 26 is a laser beam of radiation. A set of 31 optical components includes a beam splitter 28, an optical element string 30, and a mirror 34 that acts as a beam steering system to deliver the beam to the PCB. Typically, mirror 34 is a front mirror and beam splitter 28 is a narrow band dichroic solid angle beam splitter that transmits the wavelength of the beam and reflects other wavelengths. The optical element string 30 and the PCB 24 are mounted on respective translation stages 33,45. The mirror 34 is mounted on a beam steering platform 35, which is typically based on a galvanometer control platform or a two-axis fast beam steering platform as described in U.S. Patent Application Serial No. 11/472,325. U.S. Patent Application Serial No. Ser. The laser beam 26 is transmitted to the string of optical elements by a beam splitter, guided by the string of optical elements and focused.

Device 20 is configured as a "post-scan" system in which no optical components are present between mirror 34 and PCB 24. In this configuration, the field of view of the mirror is typically about ±3°.

Unless otherwise indicated, the following description focuses on micromachining the PCB 24 using a laser beam. However, it should be understood that embodiments of the present invention can operate using substantially more than one laser beam simultaneously.

The operator 23 operates the device 20 using a workstation 21 that includes a memory 25 and a processing unit (PU) 32. The PU 32 uses the instructions stored in the memory 25 to control various components of the device 20, such as the laser 22 and the translation and beam steering platform. In addition to the operating platforms 33, 35, the PU 32 can also change the focus of the string of optical elements 30 when a particular hole is being machined in the portion 43. The holes are micromachined in selected regions 42 on top surface 36 of PCB 24. The inset 44 shows the portion 43 in more detail, which includes a region 42 and an area surrounding the region.

In some embodiments of the invention, an object 46 is located below the area 42 and the object is embedded in the PCB 24 such that there is a layer 38 on the substrate and a layer 40 below the object. In general, there are other embedded objects that are proximate to the object 46, and other layers may be included in the PCB 24, but for clarity, such other embedded objects and layers are not shown in FIG. Object 46 is typically part of a circuit and layers 38 and 40 are used as substrates on which the circuit is formed. In one embodiment, object 46 is a generally circular metal pad having a diameter of approximately 100 microns. Typically, layers 38 and 40 are dielectric and are made of filled epoxy. In certain disclosed embodiments, layers 38 and 40 are assumed to be made of one of various Ajinomoto cumulative films (ABF) manufactured by Ajinomoto Fine-Techno, Inc. of NJ, such Ajinomoto cumulative film (ABF) It is well known in the art and will be described below with reference to Figures 2 and 3. In one embodiment, layers 38 and 40 are constructed of GX3 type ABF and have a thickness of approximately 35 microns. However, it should be understood that layers 38 and 40 can be made of any material suitable for constructing a printed circuit board. For example, layer 38 can comprise an ABF material and layer 40 can comprise an FR4 material.

To align the PU 32 with the PCB 24, the PCB is illuminated by illumination from a source 50, which is typically a laser diode that provides imaging radiation at the wavelength of the imaging radiation. In some embodiments, source 50 comprises a light emitting diode (LED), typically a high brightness LED. If source 50 contains a laser diode, the source typically includes a spot removal system, such as a bundle of fibers. Alternatively, or in addition, the source can be selected to have a short coherence length as described below. Apparatus 20 includes a second dichroic beam splitter 52 that is transparent to the wavelength of the beam and used as a beam splitter at approximately one-half of the wavelength of the imaging radiation. In some embodiments of the invention as described below, the beam splitter mirror 52 includes a polarization beam splitter mirror. Imaging radiation is transmitted via a focusing lens system 49 via a beam splitter 52 to be generally coaxial with the beam 26. The imaging radiation is reflected from the mirror 34 whereby the imaging radiation at the PCB 24 is substantially perpendicular to the surface 36. The imaging radiation reaching the surface 36 is configured to illuminate a relatively small area that is circumferentially adjacent to the region 42 rather than an extended region on the surface that is typically about four times the area of the portion being micromachined. about. For example, for the 100 micron exemplary pad described above, the focusing lens system 49 can be configured to provide imaging radiation in a circle having a diameter of approximately 200 microns.

By aligning the imaging radiation to illuminate a relatively small area surrounding the location at which micromachining is to be performed, high intensity illumination radiation can be efficiently provided to the area, thereby producing a high quality image of the area. By directing the imaging radiation through elements of the device 20 that are also used to direct the micromachined beam 26 to the region being positively micromachined, high intensity illumination radiation is achieved when the device 20 is realigned to micromachine the new region. The new area will be automatically realigned. Moreover, as will be described below, the return radiation for imaging is also returned via the common element of device 20 that directs beam 26 and illumination radiation, thus when realigning device 20 to micromachine a new region, New area automatic imaging. As explained in more detail below, the combination of features described above enables embodiments of the present invention to substantially simultaneously align beam 26 with portions thereof, thereby providing an overall micromachining rate for PCB 24.

The return radiation from the portion 43 is reflected by the mirror 34 via the beam splitter 52 to the optical element string 30, as indicated by the arrow 54 and transmitted from the optical element string to the beam splitter 28. The string 30 is directed to the optical sensor 56 via the beam splitter 28 and the focusing lens 55 and optionally via a filter system 53. The filter system 53 typically includes a set of optional filters, including bandpasses. Filters and long pass filters. As described below, if the site 43 produces fluorescent radiation, such a filter system can be utilized. For objects present in the portion 43 (e.g., object 46), the sensor 56 is configured to provide a signal to the PU 32 based on the location of the object, and the processing unit uses the signals to properly align the beam 26 with respect to the PCB 24 and the object. And orientation. The operation of the sensor 56 will be described in more detail with reference to Figures 5A, 5B and 5C.

In some embodiments, source 50 is used to generate fluorescent return radiation from portion 43 to, in particular, inherently free of spots from the image formed by the return radiation. The production of fluorescent images is described in U.S. Patent Application Serial No. 10/793,224, the disclosure of which is incorporated herein by reference. In such cases, source 50 may preferably comprise a laser diode operating at approximately 405 nm, and generally does not require a speckle removal system. Additionally, beam splitter mirror 52 can preferably be configured as a dichroic beam splitter mirror that reflects radiation from source 50 and transmits beam 26 and fluorescent return radiation. Preferably, PU 32 can be used to adjust the wavelength and/or power of the imaging radiation produced by source 50. By adjusting the wavelength and/or power, the effective depth of imaging radiation into the site 43 can be varied to optimize the image produced by the fluorescent radiation. If the portion 43 contains an object that does not emit fluorescence, such as a metal pad, generating an image with fluorescent radiation enhances the contrast of the image. Since the portion 43 typically includes layers having different fluorescent characteristics, as explained below, the PU 32 and/or the operator 23 can select filters from the filter set 53 to optimize the image.

In some embodiments, source 50 is selected to have a working wavelength or range of wavelengths that are substantially transparent to the PCB, such as the wavelengths given below with reference to FIG. In such a case, typically for at least a portion of the mirrored object 46, the object can be imaged as a bright object against a relatively dark background. This type can be produced when a relatively long source wavelength (as given hereinafter in Figure 2) is used with materials that are relatively transparent to such wavelengths (for example, SH9K ABF resin, GX3 ABF resin or GX13 ABF resin). Type "bright field" imaging.

Typically, the PU 32 performs a coarse alignment of the PCB 24 using the translation stage 45 and performs fine alignment using the stages 33 and 35 such that the area 42 is at the desired location on the surface 36 and the beam 26 is in a position relative to the surface. Need to be oriented. However, the beam 26 can also be positioned and oriented using any other convenient combination of translational stages 33, 45 and operation of the beam steering platform 35.

To micromachine a hole in the PCB 24 using the beam 26, the material being processed needs to be at least partially effectively absorbed to absorb the energy of the beam. Such effective absorption may be by absorption of the beam by the PCB resin at the beam wavelength, or by absorption of the beam by an object (such as glass particles or fibers) contained in the resin, or by an object embedded in the PCB (eg, object 46). achieve. Alternatively, or in addition, in the case of the short pulse lasers mentioned above, the effective absorption of the beam can be achieved by a non-linear interaction of the short pulses with the PCB resin or the embedded object. In general, since micromachining works by ablating certain portions of the PCB, the efficiency of micromachining increases as the effective absorption of the beam increases.

A number of other factors can affect the ability of device 20 to efficiently perform micromachining in PCB 24: The effective absorption of the portion of the PCB to be micromachined at the beam wavelength limits the effective imaging of objects below surface 36 (e.g., object 46) at the wavelength of the beam.

. Certain optical components of device 20 simultaneously transmit beam radiation from source 22 and imaging radiation from source 50. In addition, if fluorescent radiation is generated, the optical elements can also transmit fluorescent radiation. The three types of radiation have different wavelengths, and some of the wavelengths can be different from each other. In such cases, the optical elements of device 20 may preferably be selected to include reflective elements, refractive elements, or combinations of the two types of elements, and/or other elements such as diffractive elements, to properly transmit different wavelengths. Component selection will be apparent to those of ordinary skill in the art.

. There are practical limits on the wavelengths that can be selected for the beam, and the wavelength or range of wavelengths that can be selected for imaging radiation and fluorescent radiation (if used).

The choice of beam and imaging radiation wavelengths will vary depending on these and other factors, including the components of the PCB 24 and the optical properties of the object 46. Thus, in certain embodiments of the invention, the beam wavelength is selected to be substantially the same as the imaging radiation wavelength. For these embodiments, the imaging radiation wavelength is separated from the beam wavelength by about 50 nanometers or less. In other embodiments, the two wavelengths are selected to be different from one another such that the imaging radiation wavelength is about 100 nanometers or more from the beam wavelength. For the case of fluorescent imaging, the wavelength of the imaging radiation is chosen to produce fluorescence, and the PCB resin inherently has local absorption for the imaging radiation.

Device 20 can be used to micromachine a plurality of holes in PCB 24, which are typically used for microvias and/or blind vias. The steps involved in micromachining a plurality of holes are to align beam 26 with region 42, through which the holes are micromachined and the beam realigned to a new portion of the region having the desired micromachining. Repeat the process over and over again. In order for this process to proceed efficiently, the alignment and realignment of the beam should be performed as quickly as possible. Or alternatively, multiple sets of devices 20 can be configured to micromachine a plurality of holes substantially simultaneously. In one embodiment of the invention, 18 sets of devices 20 are simultaneously operated on a PCB.

In some embodiments of the invention, device 20 includes an element 51. The function of the element 51 will be described below with reference to Fig. 8.

Figure 2 is a schematic plot of the percent transmission of different types of ABF resins at different wavelengths and with a resin thickness of 45 microns.

By examining the graph, it is found that at a wavelength of about 350 nm corresponding to the wavelength provided by the laser 22, the laser is now a UV laser, and the SH9K ABF resin is transmitted by about 20%, while the GX3 ABF resin has high absorbency. Thus, if layer 38 is a SH9K ABF resin, source 50 can have substantially the same wavelength as laser 22 and produce return radiation from object 46. If layer 38 comprises GX3 ABF resin', to obtain the same or more return radiation as in the case of SH9K, the source wavelength should be approximately 430 nm or more. In addition to the transmission factors given in the graph of Figure 2, other factors that affect the imaging of the PCB and object 46 include the diffusion of illumination radiation due to the glass beads used to fill the epoxy of the layers 38 and 40. The size and density vary.

The inventors of the present invention have found that both types of resins are substantially transparent at near infrared wavelengths of about 800 nm or more. The inventors of the present invention have also discovered that if the source 50 operates at the same wavelength, a good image of the embedded object (e.g., object 46) will be formed regardless of the diffusion caused by the beads embedded in layers 38 and 40. .

Figure 3 is a schematic plot of fluorescence for different resin types. The curves corresponding to the ABF resins GX3, SH9K, GX13, and FR4 materials show the relationship between the normalized fluorescence intensity and the fluorescence wavelength of each of the resin materials. These curves are produced at an excitation wavelength of approximately 300 nm, but the inventors have demonstrated that at other excitation wavelengths (including the 350 nm wavelength of the UV lasers exemplified above), The curve. Certain embodiments of the present invention operate the device 20 using the fluorescent characteristics shown by the curves in FIG. For example, if layer 40 (Fig. 1) contains FR4 resin and layer 38 comprises GX3 resin, a working band pass filter having a wavelength of about 450 nm or a long pass filter having a cutoff wavelength of about the same wavelength can be used. The film is a good part of the second layer. When observing the fluorescent light of the second layer, a shorter wavelength band pass or long pass filter can be used.

4 is a flow chart 60 showing the steps performed when operating device 20 in accordance with an embodiment of the present invention.

Prior to micromachining using device 20, the device is first calibrated relative to PCB 24. The initial calibration may be to mark a panel, such as a dedicated calibration panel (other than PCB 24), to image the markers using device 20, and to determine the calibration offset of the device based on the imaged markers. In some embodiments, a portion of the PCB 24 can be marked and calibrated using the markers.

Alternatively, or in addition, as will be explained in more detail below, the device 20 can be aligned using the fluorescent characteristics shown by the curves in FIG. The following description of the various steps in flowchart 60 describes a calibration process and a micromachining process.

In a first calibration step 62, the operator 23 positions a dedicated calibration panel or PCB 24 (to be calibrated using the PCB) on the platform 45. The operator provides the device 20 with calibration target coordinates (typically coordinates of 2 to 4 calibration targets) and shapes corresponding to the targets in the calibration panel or in the PCB 24. The operator can provide the target coordinates and shape from a computer-aided manufacturing (CAM) file or can be entered directly by the operator. As noted above, such targets can be configured to be non-destructive or lossy. Alternatively, the calibration panel or PCB 24 can be mechanically positioned, typically using a reference pin, a corner, or other mechanical reference zone in the panel or PCB.

In a second calibration step 64, the operator operates the alignment system of device 20 to illuminate and position the calibration target. Illumination can be from source 50, and as described above, the wavelength of the imaging radiation of source 50 can be preferably selected such that the return radiation is fluorescent radiation. As also described above, the PU 32 can adjust the wavelength and/or power of the source 50 to optimize the resulting image.

Alternatively, or in addition, if fluorescence of the calibration target is used, the region containing the targets can be illuminated by operating the laser 22 at a power below the ablation threshold power of the PCB. In such a case, the region can be illuminated typically by defocusing the beam 26 with the optical element string 30 and operating the laser 22 in a "area illumination" mode. Alternatively, the area illumination mode can be performed by scanning the mirror 34 using the beam steering platform 35 and thereby scanning the laser beam. The calibration target is imaged on sensor 56 and PU 32 calibrates device 20 using the target image formed on the sensor. If fluorescence is used, the PU 32 and/or the operator 23 may select one of the filters 53 to optimize the formed image - typically including layers 38 and 40, for example, as described above. In the case of different resins, and as illustrated in the description of Figure 3.

The following steps assume that the PCB 24 has been calibrated and that the PCB is in place in the device 20. In the following steps, by way of example, object 46 is assumed to be an isolated, approximately circular pad, and a hole is micromachined perpendicular to surface 36 through the center of the pad. One of ordinary skill in the art will be able to detail the steps in the flow chart for other types of objects 46 (e.g., a circular pad attached to a rectangular conductor or to a connected array of circular pads). Make the necessary corrections.

In a first micromachining step 65, the operator 23 loads the CAM files corresponding to the circuits built in the PCB 24 into the memory 25.

In a second micromachining step 66, the PU 32 uses the CAM archive to determine the shape and the nominal coordinates of the shape in which a hole is to be micromachined. In the following description, it is assumed that a hole is to be micromachined at the center of the object 46, and thus the nominal coordinates may be the nominal coordinates of the object 46 or the portion 43 containing the object. Alternatively, the nominal coordinates and shape of the object 46 can be obtained by analyzing the image of the circuit, which is performed by the operator 23 and/or the PU 32.

In a third micromachining step 68, the PU 32 provides a coarse adjustment control signal to each of the fixed PCB 24, optical element string 30, and/or mirror 34 motion stages using signals corresponding to one of the nominal coordinates to cause the object 46 to move in. Within the field of view of sensor 56. This positioning can be performed completely automatically by the processing unit. Alternatively, operator 23 can generally perform such positioning at least in part by providing nominal coordinates to PU 32.

Beginning at step 68, PU 32 follows one of the two possible paths. The first path 69 reaches the object illumination step 74 via beam alignment steps 70 and 72. The second path 71 then directly reaches the object illumination step 74. When the flowchart 60 is first operated and then the flowchart 60 is periodically operated, the PU 32 follows the first path 69, and thus the beam alignment performed in steps 70 and 72 is not performed for each object being micromachined. Rather, beam alignment is performed intermittently every t seconds, where t is the parameter selected by operator 23 and is typically about 10.

In path 69, in the first beam alignment step 70, the laser 22 is operated at a low power below the ablation threshold and onto the site 43. The laser beam typically excites the phosphor at its location on the site 43 (here assumed to be region 42), in which case the return fluorescent radiation is focused on the sensor 56 to form a region on the sensor. Image of 42. Alternatively, instead of using the fluorescent light of the PCB, an ablation calibration plate has been previously attached to the portion 43.

In path 69, in a second beam alignment step 72, PU 32 records the position of the laser beam on sensor 56.

In the object illumination step 74, the PU 32 turns off the laser 22 and operates the source 50 to illuminate the object 46. Alternatively, or in addition, in step 74, the PU 32 may maintain the laser 22 at a low power and/or the area illumination mode described above. Typically, PU 32 uses the return fluorescent radiation generated from the PCB near object 46 to form the image described in the next step 76. Fluorescent radiation can be generated by radiation from the laser 22 and/or source 50. The image may be formed by returning fluorescent radiation alone or with return radiation at a wavelength of source 50. Typically, for example, for the examples of layers 38 and 40 comprising different resin types (e.g., ABF and FR4) as described above, PU 32 is selected from the filter set 53 in the case of returning fluorescent radiation. Filters to optimize the image.

In object recording step 76, PU 32 records the image of the object produced in sensor 56. The PU 32 analyzes the signal level from the sensor 56 to determine the signal corresponding to the actual center coordinates. An example of such an analysis will be described with reference to Figures 5B and 5C. If path 69 has been followed, the processing unit records and determines the offset between the actual coordinates of the center of the circular pad and the position of the beam obtained in step 72. If the path 71 has been followed, then the processing unit uses the offset obtained in the most recent execution of path 69.

In motion step 78, PU 32 adjusts the beam position relative to the center of object 46 using the offset determined in step 76. Typically, this adjustment is accomplished by operating the beam steering platform 35 to properly align the mirror 34.

In operating the laser step 80, the PU 32 switches the power of the source 22 above the ablation threshold to cause the beam to ablate the layer 38 and the object 46, and thereby at the actual coordinates of the center of the object 46. Make a hole. In some embodiments, during micromachining, the processing unit may also use the optical element string 30 to change the focus of the beam 26 as the micromachining proceeds.

In a first decision step 82, the PU 32 checks if further micromachining operations are to be performed on the PCB 24 for other portions of the PCB. If no other operations exist, flowchart 60 ends. If there are other operations - where it is assumed that the hole is to be machined at the center of the object substantially similar to object 46, then flow chart 60 proceeds to a second decision step 84.

In a second decision step 84, the PU 32 determines if the distance of the object 46 from the nominal position of an object to be processed is greater than a predetermined distance (typically about 10 mm). If the distance is greater than the preset distance, the counter N is set to 0, and the flow returns to step 66 to process the next object.

If the distance is less than or equal to the preset distance, then in a third decision step 86, the PU 32 checks if the offset recorded in step 76 is less than a predetermined value. If the offset is less than the preset value, then in step 88, the PU 32 operates the device 20 by performing steps 78 and 80 on the following N objects, where N is the counter mentioned above, and wherein N is set It is usually a predetermined value of about one of ten. The operator 23 can set the predetermined value N when loading the CAM file in step 65.

While performing step 88, the PU 32 checks whether the distance between the objects exceeds the preset distance after each processing operation. In this case, the flow returns to step 66, as indicated by the dashed line 67 in the flowchart. If the predetermined distance is not exceeded when the N objects are processed, the PU 32 completes processing the N objects, increments N, and then returns the flow to step 66.

If the offset is greater than or equal to the preset value in decision step 86, PU 32 decrements N to a minimum value of zero. In step 90, PU 32 operates the device by performing steps 78 and 80 on the following N (decreasing values) objects. While performing step 90, the PU 32 checks whether the distance between the objects exceeds the preset distance after each processing operation. In this case, the flow returns to step 66, as indicated by the dashed line 73 in the flowchart. . If the predetermined distance is not exceeded when the N objects are processed, the PU 32 completes processing of the N objects and then returns the flow to step 66.

Decision step 84 enables operator 23 to configure device 20 to process objects within a predetermined distance of an object that has been subjected to alignment steps 66-76 without performing a alignment step. In other words, the beam position is determined using a set of objects determined for a given object to be a group of objects that are close to the given object.

Decision step 86 enables the operator to configure the device such that the magnitude of the offset obtained in step 76 determines how many objects are in the group described above. Therefore, if the determined offset is lower than the preset offset, the value of N (the number of objects in the group) is incremented for a group of objects to be processed. And if the determined offset is greater than the preset offset, the value of N is decremented for a group of objects to be processed.

The operator typically enters a preset distance and a preset offset value in step 65.

The above description applies to micromachining a circular hole perpendicular to the surface 36 through the center of the circular pad. Device 20 can also perform other micromachining operations, such as non-perpendicular micromachining of a hole, and/or micromachining of a non-circular hole, such as a slit-shaped hole, and/or different from flow chart 60. Make sure that the hole is micromachined at the position corresponding to the actual coordinate. It should also be appreciated that micromachining may be used to form a hole that completely penetrates the PCB or does not completely penetrate the hole of the PCB. Those of ordinary skill in the art will be able to modify the above description for such other micromachining operations, typically by having the processing unit align the translation platform 33, translation platform 45, and/or beam steering platform 35 in steps 78 and 80. Perform further operations to achieve.

Typically, if the coarse alignment corresponding to step 68 is performed automatically, it takes approximately 1-3 milliseconds since the previous micromachined hole. If the beam steering platform 35 (Fig. 1) is based on a galvanometer, it is usually applied for a shorter period of time, and if the platform is a two-axis scanning system, it is usually applied for a longer period of time. Preferably, the fine alignment procedure described above in step 78 takes less than about 1 millisecond. The reason for achieving this time is mainly because the imaging radiation directed at each part of the micromachining has a high intensity.

The inventors have discovered that there is substantially no time loss when using process 60 to process a PCB compared to prior art systems that do not employ such steps in process 60. Additionally, steps such as decision steps 84 and 86 can be performed during processing of the PCB. Thus, process 60 can be implemented to operate substantially in real time. By operating at the stated time, relatively long-term adverse effects such as thermal drift can be eliminated. Moreover, by performing the alignment steps 70 and 72 only intermittently as described above, the total operation time is shortened without affecting the precision of the micromachining.

FIG. 5A shows a schematic diagram of one surface of an optical sensor 56 that can be used in device 20, in accordance with an embodiment of the present invention. Typically, to generate an alignment signal in the alignment time given above, the sensor 56 uses complementary metal oxide semiconductor (CMOS) technology. Alternatively, sensor 56 can include one or more CCDs (charge coupled devices), or other suitable sensing devices.

A diagram 164 illustrates the surface of the sensor 56. The sensor 56 typically includes a rectangular array of detection elements 170. Some examples of suitable image sensors are described below. Micron Technology, Inc. of Boise, Idaho, provides an MTM001 CMOS 1.3 megapixel rectangular array sensor, and the inventors of the present invention have found that such a sensor is suitable. A programmable area of interest (AOI) can be used to limit the number of components addressed in the sensor, thereby enabling the array to be used for short acquisition times of around 1-3 milliseconds. Hamamatsu Photonics K.K. of Japan provides an array of 256 x 256 sensing elements S9132 that can be used as two one-dimensional arrays and gives a sum output, as will be explained in more detail below. Those of ordinary skill in the art will be familiar with other arrays suitable for use as sensor 56.

The PU 32 can advantageously use signals from the component 170 to accurately determine a particular location with respect to the object 46. Figures 5B and 5C show examples of images of object 46. For example, assume that object 46 includes a circular pad and that the center of the circular pad is to be micromachined. In Figure 5B, object 46 includes an isolated, approximately circular pad that produces image 166. In Figure 5C, object 46 includes an approximately circular pad attached to one of the rectangular conductors that produces an image 176 formed by a circular portion 178 coupled to a rectangular portion 180.

If the sensor 56 includes a rectangular array of individual pixels (such as the Micron array mentioned above), for the image 166, the PU 32 can reduce the number of pixels to be analyzed to one of the rectangular pixels 168 of the surrounding image 166. Reducing the number of pixels reduces the time it takes to capture images. The PU 32 can then fit all of the imaging pixels to a circle, typically using an edge detection algorithm to identify the center of the image 166 with sub-pixel precision.

For example, by using 100×100 pixels out of 1.3 megapixels, the image acquisition time can be improved by nearly 100 times compared to the nominal frame rate of 30 Hz, thereby providing sub-millisecond acquisition time. Such a short acquisition time requires a high image illumination intensity, which is provided by the illumination of the directional portion from source 50 via mirror 34 (Fig. 1).

For image 176, PU 32 may reduce the number of pixels to be analyzed to one of the rectangular pixel sets 179 of surrounding portion 178 (possibly removing some of the pixels in rectangular portion 180). With an edge detection algorithm, the PU 32 can then fit the imaging pixels that form a non-linear edge to a circle to identify the center of the circular portion 178 with sub-pixel precision. Alternatively, the PU 32 can fit all of the pixels to an expected theoretical edge using an edge detection algorithm that is created by a circle intersecting two parallel lines on one side of the circle.

In general, the pixels that PU 32 selects for analysis do not need to be a simple rectangular array. For example, the imaging site can include a small circular pad attached to a large circular pad, in which case the pixel selected by the PU 32 can be configured to encompass the generally irregular set of pixels selected for that portion. .

Sensor 56 can include an array that does not give an output for each pixel in the array, such as the Hamamatsu array mentioned above. In this case, PU 32 may apply a curve fit to the sum output of the array to find the centers of images 166 and 178.

Figure 6 is a schematic illustration of a beam alignment device 320 in accordance with an alternate embodiment of the present invention. Except for the differences described below, the operation of device 320 is generally similar to the operation of device 20 (Fig. 1), and the elements represented by the same reference numerals in devices 20 and 320 are generally similar in construction and operation.

Device 320 includes a beam splitter 326 with beam splitter 52 removed. Beam splitter mirror 326 is used to transmit imaging radiation from source 50 and to reflect radiation returning from portion 43 to sensor 56. If the return radiation has the same wavelength as the source 50, the beam splitter can be a 50/50 beam splitter. If the radiant radiation is returned, the beam splitter 326 can be configured as a dichroic beam splitter. Alternatively, as described below, the beam splitter 326 can be a polarizing beam splitter.

In device 320, optical element string 30 is separated into two sets of optical elements. The first set 324 typically includes movable optical elements that can be used to vary the magnification of the beam from source 22. The second set 322 typically includes a fixed optical component. By dividing the optical element string 30 into the two groups, the magnification of the beam from the source 22 can be adjusted without affecting the illumination and the imaging path between the beam splitter 28 and the mirror 34.

Elements 323 and 325 in device 320 will be described below.

If the normal imaging illumination provided in device 320 is substantially uniform over portion 43, i.e., if the illumination has little or no structure at all, the image obtained by specular object 46 is typically a contrast of the bright image of the object. A dark background image of the area of the object, and the two images have a good contrast.

After considering the devices 20 and 320, it will be discovered that optical elements such as the steerable mirror 34 and the optical element string 30 can deliver at least two different wavelengths, namely the beam wavelength of the beam 26 and the imaging radiation wavelength of the source 50. If fluorescent light is used, the optical elements can deliver three different wavelengths, namely the beam wavelength, the imaging radiation wavelength, and the fluorescent wavelength. Configuring the same components to deliver two or three different wavelengths significantly reduces the number of optical components that may be required if a separate set of components are used for different wavelengths.

Figure 7 is a schematic illustration of a beam alignment device 330 in accordance with yet another alternative embodiment of the present invention. The operation of device 330 is generally similar to the operation of device 20 (Fig. 1) and device 320 (Fig. 7), except for the differences described below, and the components represented by the same reference numerals in devices 20, 320 and 330 are The construction and operation are generally similar.

Device 330 includes a lens system 336 between mirror 34 and portion 43. Lens system 336 typically includes a telecentric lens that enables mirror 34 to have an FOV of about ±20°. Adding the lens system will configure device 330 as a "pre-scan" system. The larger the FOV of the mirror, as compared to the scanning system described above, enables the mirror to project the beam 26 onto the larger area of the PCB 24 and image the area.

The optical element sets 324 and 322 are typically reconfigured to include a first set 334 of movable elements and a second set 332 of fixed elements, respectively, the sets 334 and 332 being selected to accommodate the lens system 336.

The above description of devices 20, 320, and 330 assumes that the imaging illumination is generally perpendicular to surface 36 and is generally unstructured. In some embodiments of the invention described below, the imaging illumination can also be configured to have the illumination structured as described below.

Figure 8 illustrates an imaging radiation configuration 344 provided by source 50 in accordance with an embodiment of the present invention. The figure shows a cross-sectional view 340 and a top view 342 of the PCB 24 in the case of a radiation configuration 344. In configuration 344, the imaging radiation on surface 36 is structured into imaging radiation, for example, in the shape of a generally circular ring 346. The imaging radiation penetrates layers 38 and 40 and is also locally scattered within the layers due to diffusion within the layers, such as primarily due to the filler material contained in the layers. The combination of penetration and local scattering effectively "self-backlit" the object 46, as indicated by arrow 348, thereby forming a high contrast image on the sensor 56. Regardless of whether the object 46 is mirrored, a high contrast image is produced. In addition, high contrast images formed by backlighting can effectively compensate for image blurring that may be caused by radiation diffusion within the layers. If the backlight is not used, the image blur can cause deviations in the measured position of the image.

A radiation arrangement 344 can advantageously be provided in device 20 by placing an element 51 (Fig. 1) (typically a stop) between lens 49 and beam splitter 52. Although not shown in the figures for clarity, a configuration 344 can also be provided in device 320 by placing a suitable stop between lens 55 and beam splitter 28. Other methods for forming annular radiation in devices 20, 320, and 330 (e.g., using diffractive elements designed to achieve structured illumination) will be apparent to those of ordinary skill in the art and are believed to include Within the scope of the invention. For example, element 51 can comprise such a diffractive element. Source 50 can provide other forms of structured illumination that are typically structured according to the location being imaged. For example, a rectangular illumination can be used to illuminate an area around a generally linear trace. All such forms of structured illumination are considered to be still within the scope of the present invention.

To obtain configuration 344, source 50 can be selected as a laser emitter having a very short coherence length so that there are substantially no spots. The inventors have found that a laser having a coherence length of about 1-2 times the size of the object being processed (e.g., the diameter of a circular pad) is suitable for this.

Referring again to Figure 6, an alternative radiation configuration uses polarized illumination radiation. As shown in FIG. 6, a polarizer 323 can be placed after source 50 and an analyzer 325 placed in front of sensor 56. Alternatively, since source 50 typically provides polarized radiation, polarizer 323 may not be required. The orientation of polarizer 323, or the orientation of source 50 (if its radiation is polarized), and the orientation of analyzer 325 can be controlled by PU 32. Alternatively, the orientations can be preset by the operator 23 to a substantially fixed value. The reflection of the surface 36 and the intermediate surface of the PCB 24 (e.g., the interface between layer 38 and layer 40) is substantially the same as the incident polarization of the low incident angle. The backscattered radiation from layers 38 and 40 is relatively weak and is primarily polarized in the same direction as the incident polarized radiation. However, if the object 46 has even a partially roughened metal surface (as is often the case for improving the adhesion between the object and its embedded resin), the reflected radiation is substantially depolarized and thus has a 90° angle with the incident polarized radiation. The component of the angle. In an alternative configuration described herein, the PU 32 sets the polarizer 323 and analyzer 325 to have crossed polarizations, or the operator 23 presets the orientations such that the surfaces and layers 38 and 40 are inside. The specular reflection is absorbed and the depolarized radiation from object 46 is transmitted. The polarization of the intersection thus provides a good image of the object 46 with a high contrast to the material surrounding the object.

In an alternative embodiment for polarizing illumination radiation, neither polarizer 323 nor analyzer 325 is used. Rather, source 50 is constructed to provide polarized illumination, and beam splitter 326 is configured to be a polarizing beam splitter that transmits polarized illumination from the source. The polarizing beam splitter mirror is used to reflect the depolarized radiation (including radiation from object 46) to sensor 56, thereby forming a good image of the object as described above.

Referring again to FIG. 1, the beam splitter 52 can be configured as a polarizing beam splitter at the wavelength of the source 50 such that the image of the object 46 formed by the sensor 56 in the device 20 is substantially similar to that in the device 320. The image formed.

The polarization embodiment described above enables the sensor 56 to perform polarization analysis of the return radiation from the object 46 and its surroundings.

In each polarization embodiment, to reduce speckle, source 50 can include a laser emitter having a coherence length that is less than the size of the object being processed. For example, for a circular pad, the coherence length can be significantly less than the pad diameter. Other methods can also be used to reduce the spots, for example using the methods exemplified above.

The various embodiments described above relate to adjusting the actual micromachining position of the PCB using optical images of the PCB 24 and/or the embedded object 46. However, it should be understood that the PU 32 may also use the PCB and/or other types of images of the embedded object to determine the actual location desired. Moreover, it should be understood that embodiments of the present invention can also be used to image objects embedded in or on materials other than PCBs, such as ceramic or glass. Those of ordinary skill in the art will be able to adapt the above description to the changes required for other types of images without undue experimentation.

It is to be understood that the above-described embodiments are described by way of example, and the invention is not intended to Rather, the scope of the invention is to be construed as being inclusive of the various combinations and sub-combinations of the various features described above, as well as variations and modifications which are apparent to those skilled in the form.

20. . . Beam aligning device

twenty one. . . workstation

twenty two. . . Beam source

twenty three. . . operator

twenty four. . . Printed circuit board (PCB)

25. . . Memory

26. . . Radiation beam

27. . . Collimator

28. . . Beam splitter

30. . . Optical component string

31. . . a set of optical components

32. . . Processing unit (PU)

33. . . Translation platform

34. . . mirror

35. . . Beam steering platform

36. . . Top surface

38. . . Floor

40. . . Floor

42. . . Selected area

43. . . Part

44. . . illustration

45. . . Translation platform

46. . . object

49. . . Focusing lens system

50. . . Radiation source

51. . . element

52. . . Second dichroic beam splitter

53. . . Filter system

54. . . arrow

55. . . Focusing lens

56. . . Optical sensor

164. . . figure

166. . . image

168. . . Rectangular pixel set

170. . . Rectangular detection element array

176. . . image

178. . . Round part

179. . . Rectangular pixel set

180. . . Rectangular part

320. . . Beam aligning device

322. . . Second set of optical components

323. . . element

324. . . First set of optical components

325. . . element

326. . . Beam splitter

330. . . Beam aligning device

332. . . Second set of optical components

334. . . First set of optical components

336. . . Lens system

340. . . Sectional view

342. . . Top view

344. . . Radiation configuration

346. . . Generally annular shape imaging radiation

348. . . arrow

1 is a schematic view of a beam aligning device according to an embodiment of the present invention; and FIG. 2 is a graph showing a percentage transmission of different types of Ajinomoto Build-up Film (ABF) resin; A schematic graph of normalized fluorescence for different types of ABF resin and FR4 resin; FIG. 4 is a flow chart showing steps performed by operating the beam alignment device in accordance with an embodiment of the present invention; The figure shows a schematic view of one surface of an optical sensor according to an embodiment of the invention; FIGS. 5B and 5C show a schematic view of the image on the sensor shown in FIG. 5A according to an embodiment of the invention; A schematic diagram of a beam aligning device in accordance with an alternative embodiment of the present invention; FIG. 7 is a schematic diagram of a beam aligning device in accordance with yet another alternative embodiment of the present invention; and FIG. 8 illustrates an embodiment of the present invention in accordance with an embodiment of the present invention An imaging illumination arrangement provided by a source in the apparatus shown in Figures 1, 6, and/or 7.

20. . . Beam aligning device

twenty one. . . workstation

twenty two. . . Beam source

twenty three. . . operator

twenty four. . . Printed circuit board (PCB)

25. . . Memory

26. . . Radiation beam

27. . . Collimator

28. . . Beam splitter

30. . . Optical component string

31. . . a set of optical components

32. . . Processing unit (PU)

33. . . Translation platform

34. . . mirror

35. . . Beam steering platform

36. . . Top surface

38. . . Floor

40. . . Floor

42. . . Selected area

43. . . Part

44. . . illustration

45. . . Translation platform

46. . . object

49. . . Focusing lens system

50. . . Radiation source

51. . . element

52. . . Second dichroic beam splitter

53. . . Filter system

54. . . arrow

55. . . Focusing lens

56. . . Optical sensor

Claims (46)

A method for micromachining a material, comprising: configuring an optical system to provide illumination of an illumination wavelength at a portion of the material via a given component of the optical system, the illumination generating return radiation from the portion; The optical system receives the return radiation via the given component and forms an image of the portion according to the image; calculates an actual position of the location at the location according to the image, and outputs an actual position indicating the location Generating a micromachined radiation beam having a micromachined wavelength different from the illumination wavelength; determining the position of the beam relative to the location in response to the signal to form an alignment beam; and at least via the optical system The given element transmits the alignment beam to the location to perform a micromachining operation at the location. The method of claim 1, wherein the portion comprises an object embedded in the at least one insulating substrate. The method of claim 2, wherein providing illumination to the portion comprises providing structured illumination that only illuminates an area surrounding the object. The method of claim 3, wherein providing the structured illumination comprises forming the structured illumination with a diffractive element. The method of claim 1, wherein providing illumination to the portion comprises selecting the illumination wavelength to be a wavelength that causes the portion to emit fluorescence, and wherein the return radiation comprises a firefly generated at the portion due to illumination provided Light radiation. The method of claim 5, comprising filtering the fluorescent radiation to optimize imaging of the portion. The method of claim 1, wherein providing illumination to the portion comprises providing polarized illumination to the portion, and wherein the image forming the portion comprises polarization analysis of the returned radiation from the portion. The method of claim 1 wherein the given component comprises a steerable mirror. The method of claim 8, wherein the portion includes a plurality of different sub-portions in which micromachining is to be performed, and wherein determining the position of the beam comprises directing the beam to the plurality of different ones by merely manipulating the mirror Subpart. The method of claim 1, wherein the given element comprises a string of optical elements for focusing the beam and the illumination to the location. The method of claim 1, wherein the portion comprises a portion of the region, and wherein providing illumination to the portion comprises providing illumination to the portion of the portion and to another region that is no greater than and adjacent to the portion of the portion. The method of claim 11, wherein the forming the image comprises forming the image on an image sensor, and wherein the illumination has an intensity of the image generated on the image sensor within 3 milliseconds or less. . The method of claim 11, wherein forming the image comprises forming the image on an image sensor comprising an array of pixels, and selecting pixels from the array for analysis according to the region and the other region The image. The method of claim 1 , comprising determining a nominal location of the location prior to providing the illumination to the location, and providing the illumination in response to the nominal location. The method of claim 1, wherein generating the micromachined radiation beam comprises: Generating a low power beam having a power below an ablation threshold of the portion; transmitting the low power beam to the location; and determining the beam due to an image of the low power beam at the location An offset. The method of claim 15 wherein determining the position of the beam comprises determining the position of the beam due to the amount of offset. The method of claim 15, wherein the transmitting the beam of the determined position to the location comprises setting the beam to have a power equal to or greater than the ablation threshold. The method of claim 1, comprising configuring the illumination wavelength to have a value that renders the portion non-absorbent. The method of claim 1 wherein the portion comprises an outer surface, and wherein providing illumination to the portion comprises illuminating the portion with imaging radiation perpendicular to the outer surface. The method of claim 1 wherein providing illumination to the portion comprises providing coherent imaging radiation at the portion, the coherent imaging radiation having a coherence length equal to or less than twice the size of one of the portions. The method of claim 1, wherein calculating the actual location comprises: providing a theoretical relationship according to one of the expected images of the location; determining an actual relationship based on the image; and fitting the actual relationship to the theoretical relationship. The method of claim 1, wherein the image forming the portion includes an adjustment At least one of the illumination wavelength and one of the illumination powers to change a penetration depth of the illumination at the location. The method of claim 1 wherein the portion comprises an object embedded in a diffusing layer and comprising compensating for the image formed by the object embedded in the diffusing layer to cause a deviation. An apparatus for micromachining a material, comprising: a radiation source for providing illumination of an illumination wavelength at a portion of the material via a given component of an optical system, the illumination generating return radiation from the portion An image sensor for receiving the return radiation by the given component and thereby forming an image of the portion; a beam source for generating a micromachined radiation beam, the micromachined radiation beam Having a micromachining wavelength different from the illumination wavelength; and a processor for calculating an actual position of the location at the location based on the image and outputting a signal indicative of the actual location of the location, corresponding to the signal Determining a position of the beam relative to the location to form an alignment beam, and operating the beam source to deliver the alignment beam to the location via at least the given component of the optical system for execution at the location A micromachining operation. The device of claim 24, wherein the portion comprises an object embedded in the at least one insulating substrate. The device of claim 25, wherein providing illumination to the portion comprises providing structured illumination that only illuminates an area surrounding the object. The device of claim 26, comprising a diffractive element forming the structured illumination. The device of claim 24, wherein the illumination wavelength comprises causing the portion to emit a wavelength of fluorescence, and wherein the return radiation comprises fluorescent radiation generated at the portion due to illumination provided. The device of claim 28, comprising: a filter for filtering the fluorescent radiation, wherein the processor is configured to select one of the set of filters, and the image is optimized for the portion . The device of claim 24, wherein the illumination comprises polarized illumination and comprises a polarization element that enables the image sensor to perform polarization analysis of the return radiation from the portion. The device of claim 24, wherein the given component comprises a steerable mirror. The device of claim 31, wherein the portion includes a plurality of different sub-portions in which micromachining is to be performed, and wherein determining the position of the beam comprises directing the beam to the plurality of different ones by merely manipulating the mirror Subpart. The device of claim 24, wherein the given element comprises a string of optical elements for focusing the beam and the illumination to the location. The device of claim 24, wherein the portion comprises a portion of the region, and wherein providing illumination to the portion comprises providing illumination to the portion of the portion and to another region that is no greater than the portion of the portion and adjacent thereto. The device of claim 24, wherein the illumination has an intensity of the image produced on the image sensor within 3 milliseconds or less. The device of claim 24, wherein the image sensor comprises a pixel array a column, and wherein the processor is configured to select pixels from the array for analyzing the image in response to the region and the other region. The device of claim 24, wherein the processor is configured to determine a nominal location of the location before the source of illumination provides the illumination to the location, and wherein the processor is configured to instruct the source to provide the location based on the nominal location illumination. The apparatus of claim 24, wherein generating the micromachined radiation beam comprises generating a low power beam having a power below an ablation threshold of the portion, and wherein the processor is to use the low power The beam is transmitted to the location and an offset of the beam is determined based on an image of the low power beam at the location on the image sensor. The device of claim 38, wherein determining the position of the beam comprises determining the position of the beam due to the amount of offset. The apparatus of claim 39, wherein the transmitting the alignment beam to the location comprises setting the beam to a power having a threshold equal to or greater than the ablation threshold. The device of claim 24, comprising configuring the illumination wavelength to have a value that renders the portion non-absorbent. The device of claim 24, wherein the portion comprises an outer surface, and wherein providing illumination to the portion comprises illuminating the portion with imaging radiation perpendicular to the outer surface. The device of claim 24, wherein the source of radiation is to provide coherent imaging radiation at the location, the coherent imaging radiation having a coherence length that is once equal to or less than twice the size of one of the locations. The device of claim 24, wherein the processor is configured to: Receiving a theoretical relationship based on one of the expected images of the location; determining an actual relationship based on the image; and fitting the actual relationship to the theoretical relationship. The device of claim 24, wherein the processor is operative to adjust at least one of the illumination wavelength and the illumination power to change a penetration depth of the illumination at the location. The device of claim 24, wherein the portion comprises an object embedded in a diffusing layer, and wherein the processor is configured to compensate for a deviation caused by the image formed by the object embedded in the diffusing layer .