Layer transfer preparation of a semiconductor article by laser-induced defect generation

Abstract

Methods and systems for layer transfer preparation of a semiconductor article by laser-induced defect generation are described herein. One illustrative method is performed by positioning a laser to operate from a growth side of a semiconductor article that includes a starting substrate, a growth substrate layer deposited on the starting substrate, and an epitaxial layer deposited on the growth substrate layer, the growth side corresponding to the epitaxial layer; configuring the laser to emit light to a focal point within the growth substrate layer, the light having a photon energy less than a bandgap associated with the epitaxial layer; and operating the laser to generate a defect at the focal point within the growth substrate layer. This defect can be included in a pattern of defects induced by the laser. Corresponding methods and systems for completing the layer transfer after preparation of the semiconductor article are also disclosed.

Description

LAYER TRANSFER PREPARATION OF A SEMICONDUCTOR ARTICLE BY LASER- INDUCED DEFECT GENERATIONBACKGROUND

[0001] Semiconductor fabrication involves intricate processes of transforming raw materials into functional electronic components like transistors, integrated circuits, light emitting diodes (LEDs), and so forth. Fabrication of these semiconductor products may involve a series of precise steps, including depositing thin films of materials, patterning circuits using photolithography and etching techniques, and finally connecting everything through metallization.

[0002] For certain semiconductor products, it may be advantageous to fabricate a particular component (e.g., an LED) on one semiconductor article (e.g., one semiconductor wafer), and then, once the structure of the component is complete, to transfer the component onto a separate semiconductor article (e.g., a different wafer) where the component may be operated and used (e.g., a backplane with circuitry to drive the LED). This two-step fabrication process may facilitate fabrication efficiency and allow for strengths of different materials and processes to be leveraged while ultimately achieving a desired result on an optimal platform.SUMMARY

[0003] Methods and systems for layer transfer preparation of a semiconductor article by laser-induced defect generation are described herein. For various reasons, it may be desirable to fabricate certain electronic components on one wafer using one process and to then transfer these components to a different wafer that has been fabricated using another process. For example, it may be useful to densely fabricate a large number of microLEDs on one wafer and to then transfer these to a backplane fabricated on a different wafer and configured to host the microLEDs (perhaps at a lower density ) and facilitate driving them in accordance with a display controller. While the transfer process may be relatively straightforward when certain materials are used in the component fabrication (e.g., microLEDs fabricated on a sapphire substrate), certain challenges may arise when other materials are used (e.g., microLEDs fabricated on a silicon substrate). Methods and systemsdescribed herein facilitate layer transfer (i.e., the transfer of relevant semiconductor layers from a donor wafer to a receiver wafer) for straightforward and challenging cases alike by using a first laser from a first side of a donor wafer to introduce a pattern of defects into the wafer and then, leveraging this pattern of defects, using a second laser from the opposite side of the wafer to effectively and cleanly detach the relevant layer(s) and thereby complete the layer transfer.

[0004] To this end. one implementation described herein involves a method for layer transfer preparation that may be performed by a system such as a semiconductor fabrication system. This example method may include, for instance: 1) positioning a laser to operate from a growth side of a semiconductor article that includes a starting substrate, a growth substrate layer deposited on the starting substrate, and an epitaxial layer deposited on the growth substrate layer (where the growth side corresponds to the epitaxial layer and is opposite the starting substrate); 2) configuring the laser to emit light to a focal point within the growth substrate layer, the light having a photon energy less than a bandgap associated with the epitaxial layer (e.g.. so as to avoid impacting or damaging the delicate epitaxial layer by making the epitaxial layer transparent to the laser); and 3) operating the laser to generate a defect at the focal point within the grow th substrate layer.

[0005] The defect may be included in a pattern of defects induced by the laser and, as will further be described herein, may be used to help produce an effective layer transfer of the epitaxial layer (and at least a portion of the growth substrate layer) to an additional semiconductor article after the semiconductor article is prepared using the method above. For example, if the semiconductor article is a donor wafer on which microLEDs have been densely fabricated, the pattern of defects may facilitate an effective transfer of the microLEDs from the semiconductor article to an additional semiconductor article implementing, for example, a backplane configured to host the microLEDs (e.g., to carry the microLEDs at a desired pitch that may be greater than the dense pitch at which the microLEDs were fabricated, to provide circuitry to drive and control the microLEDs, etc.).

[0006] Another implementation described herein involves a semiconductor article comprising a starting substrate, a grow th substrate layer deposited on the starting substrate, an epitaxial layer deposited on the growth substrate layer, and a pattern of defects generated within the growth substrate layer. The pattern of defects may be induced by a laser operating from a growth side of the semiconductor article that corresponds to the epitaxial layer and is opposite the starting substrate. For example, the laser may be configured to emit light with a photon energy less than a bandgap associated with the epitaxial layer, the light being focusedto a focal point within the grow th substrate layer. Again, as described above, this semiconductor article and the pattern of defects introduced therein may be useful for transferring components such as microLEDs to a semiconductor article in accordance with various principles described herein.

[0007] Yet another implementation described herein involves a system (e.g., a semiconductor fabrication system) configured to perform methods such as the example method described above to produce semiconductor articles such as the semiconductor article described above. For example, the system may include: 1) a laser configured to emit light having a photon energy' less than a bandgap associated with an epitaxial layer of a semiconductor article that includes a starting substrate, a growth substrate layer deposited on the starting substrate, and the epitaxial layer deposited on the growth substrate layer; and 2) one or more processors communicatively coupled to a memory and configured to execute instructions stored w ithin the memory to perform a process. Like the method described above, this process performed by the one or more processor may include: 1) positioning the laser to operate from a growth side of the semiconductor article, the growth side corresponding to the epitaxial layer and being opposite the starting substrate; 2) configuring the laser to emit the light to a focal point within the growth substrate layer; and 3) operating the laser to generate a defect at the focal point within the growth substrate layer, the defect included in a pattern of defects induced by the laser. The system may also be configured to further process the semiconductor article, with its pattern of defects, to produce a layer transfer that, for example, detaches microLEDs fabricated on the semiconductor article and attaches the microLEDs to driver circuitry' implemented on an additional semiconductor article.

[0008] In still other implementations, any of these methods and / or processes may be embodied on non-transitory computer-readable media. For example, a non-transitory computer-readable medium may store instructions that, w hen executed, cause one or more processors of a fabrication system to perform processes described herein (e.g., methods including operations such as those described above).

[0009] Various additional operations may be added to these processes and methods as may serve a particular implementation, examples of which will be described in more detail below'. Additionally, it will be understood that each of the processes and operations described as being performed by different types of implementations in the examples above may additionally or alternatively be performed by other types of implementations as well. For example, a process described above as being embodied by a computer readable mediumcould be performed as a method and could be performed by a processor of a semiconductor fabrication system. Similarly, a method set forth above could be encoded in instructions stored by a computer readable medium or otherwise stored within the memory of a semiconductor fabrication system, and so forth.

[0010] The details of these and other implementations are set forth in the accompanying drawings and the description below. Other features will also be made apparent from the following description, drawings, and claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 shows illustrative aspects of an example implementation of a semiconductor article at different times during a process of layer transfer preparation of a semiconductor article by laser-induced defect generation and layer transfer of the prepared semiconductor article in accordance with principles described herein.

[0012] FIG. 2 shows an illustrative fabrication system configured to perform layer transfer preparation of a semiconductor article by laser-induced defect generation and layer transfer of the prepared semiconductor article in accordance with principles described herein.

[0013] FIG. 3A shows an illustrative method for layer transfer preparation of a semiconductor article by laser-induced defect generation in accordance with principles described herein.

[0014] FIG. 3B shows an illustrative method for layer transfer using a semiconductor article prepared in accordance with the method of FIG. 3A in accordance with principles described herein.

[0015] FIG. 4 shows illustrative defects that may be generated within a growth substrate layer of a semiconductor article in accordance with principles described herein.

[0016] FIG. 5 shows illustrative details of an epitaxial layer configured to undergo layer transfer after being prepared using laser-induced defect generation in accordance with principles described herein.

[0017] FIGS. 6A-6B show illustrative aspects of a localized layer transfer from one semiconductor article to an additional semiconductor article in accordance with principles described herein.

[0018] FIGS. 7A-7B show illustrative aspects of a full layer transfer from one semiconductor article to an additional semiconductor article in accordance with principles described herein.

[0019] FIG. 8 shows an illustrative computing system that may be used to implementvarious devices and / or systems described herein.DETAILED DESCRIPTION

[0020] Methods and systems for layer transfer preparation of semiconductor articles by laser-induced defect generation are described herein, as well as layer transfer completion using semiconductor articles prepared in these ways.

[0021] In the manufacture of certain types of electronic components or devices, it may be efficient, convenient, or even necessary for various reasons to fabricate certain parts of the component or device on a semiconductor article (e.g., a first wafer) using a first process, to fabricate other parts of the component on a second semiconductor article (e.g., a second wafer) using a second process, and to then combine these together to form the complete component or device (which may then undergo further processing, in some cases, to form the final product). In some cases, a subset of layers (i.e., certain layers but not including all the layers such as the starting substrate) from the first semiconductor article may be transferred to the second semiconductor article in a process referred to herein as a layer transfer. As used herein, layer transfer preparation therefore refers to techniques, processes, and / or operations that relate to preparing one or more layers on the first semiconductor article to be transferred properly to the second semiconductor article.

[0022] Principles described herein may apply to a variety of types of electronic (e.g., semiconductor-related) products and devices that involve a manufacturing process in which one wafer (referred to herein as a growth wafer or a donor wafer) is used for fabricating or growing elements that then may undergo a layer transfer from that wafer to another wafer (referred to herein as a carrier wafer or a receiver wafer). For example, different aspects of a semiconductor product may be fabricated using different technologies or processes or may otherwise have different features (e.g., geometric features such as pixel pitch, which will be described for one example in more detail below) that make it convenient to bifurcate the fabrication process for the different parts of the end product. While these principles may apply to a variety of products and situations, however, the following description, for sake of clarity, focuses on a particular example of a particular type of semiconductor product. Specifically, the present disclosure will focus on microLED products (e.g., pixel panels and display devices using microLED technologies), which may be manufactured in a manner that separates the fabrication of the microLED components themselves (which may be convenient to pack together tightly and to manufacture using certain materials and / or technologies) and the fabrication of a backplane that will ultimately host the microLED components (whichmay host the microLED components at a less dense pitch and / or may be manufactured using other materials and / or technologies).

[0023] In these types of examples, microLEDs may be implemented by certain layers (e.g., epitaxial layers) grown on a first semiconductor article (e.g., a first wafer) and these layers may be layer transferred onto backplane or carrier circuitry fabricated on a second semiconductor article (e.g., a second wafer). As used herein, a semiconductor article may refer to a semiconductor wafer in any of various stages of fabrication (e.g.. before or after various layers have been grown on a starting substrate, etc ), any portion of such a wafer (e.g., a single die or a plurality of dies fabricated on the wafer, etc.), or another similar semiconductor product. In cases where aspects of tw o separate semiconductor articles are combined, both the donor and receiver articles, as well as the final product that includes aspects of both (i.e., the backplane hosting the microLEDs) may be referred to herein as semiconductor articles. For example, as described in various examples herein, a layer transfer of microLEDs fabricated on a donor or growth semiconductor article may be performed to transfer the microLEDs onto backplane circuitry of a receiver or carrier semiconductor article. After the layer transfer is complete, the combined semiconductor article would then include both the backplane circuitry and the microLEDs being hosted thereon.

[0024] As mentioned, in some cases, the desired density7or pixel pitch for the microLED components when implemented in the final product (e.g., the pixel panel that includes backplane elements such as controllers and pixel drivers and the microLEDs themselves) may be less than the density' or pitch with which the microLED components are fabricated on the first semiconductor article. As such, the layer transfer may involve a large number of transfer operations with respect to a large number of specific local areas (e.g., individual microLEDs or individual pixels with a small number of differently colored microLEDs) from a first semiconductor article (e.g., the microLED wafer) to corresponding parts of a second semiconductor article (e.g., the backplane wafer). In other examples, layers associated with larger portions of the first semiconductor article (e.g., up to the entire semiconductor article) may be transferred in a single transfer operation. In this case, the pitch or density would not change, as will be described and illustrated in more detail below.

[0025] When certain processes and / or materials are used in the fabrication process, layer transfer may be more straightforward than when other processes and / or materials are used. For example, a sapphire starting substrate may be used to grow a gallium nitride (GaN) growth substrate layer, which may then be used to grow one or more epitaxial layers (also referred to as epilayers or quantum layers) in which indium is added to the GaN at aparticular ratio (depending on what color of LED is being produced). In this way, an indium gallium nitride (InGaN) quantum well is created that can release energy in the form of a desired color of light. Because the bandgap of sapphire is such that sapphire is transparent to ultraviolet (UV) light, it may be relatively straightforward to invoke layer transfer from a microLED semiconductor article formed using a sapphire starting substrate (i.e., grown on a sapphire wafer). For example, a UV laser may be positioned on a substrate side of the semiconductor article (i.e.. behind the sapphire substrate) and used to shine through the sapphire material to invoke the GaN layer transfer as desired.

[0026] Certain technical problems may be encountered in the layer transfer process, however, when other types of materials are used to fabricate the microLED semiconductor article. In one example scenario, for instance, the semiconductor article containing the backplane or earner circuitry may be fabricated on silicon (Si) using a complementary metal- oxide-semiconductor (CMOS) technology. In this scenario, various complications may arise if sapphire-based LEDs are transferred onto the silicon-based backplane circuitry, at least because silicon and sapphire have different thermal expansion properties (e.g., different coefficients of thermal expansion (CTEs). etc.). For example, even if sapphire-based components are transferred to the silicon-based carrier circuitry at room temperature, significant issues could occur when further processing steps, testing, or operation of the semiconductor article involves heating the combined semiconductor article to a higher temperature. For example, as the hybrid semiconductor article is heated to 300° in a later processing step, the different thermal expansion properties of the silicon-based carrier circuitry and the sapphire-based LEDs could cause stress and strain on the hybrid circuit and, in the worst case, could lead to issues up to and including delamination of the layers. When delaminated, the applied microLEDs become unattached from the underlying carrier circuitry to render the circuit unusable.

[0027] At least one technical solution to the technical problem of mismatched CTEs of different semiconductor articles being combined is to avoid the mismatch altogether. For example, if the carrier circuitry’ is fabricated on silicon, one solution is to also fabricate the microLEDs on silicon (rather than sapphire) as well so that the CTEs and other thermal properties will match and problems associated with differing temperatures (e g., delamination, etc.) can be avoided. Unfortunately, an additional technical problem may arise when the microLEDs are fabricated using the silicon starting substrate rather than the sapphire substrate. Unlike sapphire, silicon is not transparent to UV light, so the UV laser cannot be used in the same straightforward manner to release (i.e., invoke the layer transfer)the microLEDs from the silicon-based semiconductor article.

[0028] To address this later technical problem (and to thereby also provide support for the solution to the former technical problem), methods and systems described herein facilitate layer transfer from a donor semiconductor article to a receiver semiconductor article even in challenging scenarios like the one described above involving releasing microLEDs from the (non-transparent-to-UV) silicon substrate. More particularly, methods and systems described herein provide at least one technical solution to this problem by facilitating layer transfer preparation of a semiconductor article (e.g., a silicon-based semiconductor article) by laser-induced defect generation. For example, as will be described in more detail below, a laser configured to produce light with one photon energy may be used from the front side (e.g., a growth side where epitaxial layers have been grown and opposite to the back side or substrate side where the starting substrate is) to introduce defects within a growth layer that make it easier and cleaner for this layer to be released or transferred. These defects may be analogous, for example, to small holes in a paper card that has a perforation and is intended to be cleanly and efficiently detached from a remainder of a sheet on which the card is printed. By preparing the semiconductor article with a pattern of defects in the ways described herein (e.g., using a laser from the growth side), the layer transfer may be effectively and efficiently performed by using another laser configured to produce light with a different photon energy- (e.g., an energy less than a bandgap of silicon so that silicon is transparent) from the substrate side.

[0029] While this two-stage process (e.g., preparing the semiconductor article and then performing the layer transfer) is slightly more involved than a one-stage layer transfer that may be possible with something like a sapphire-based semiconductor article, the technical effects of this solution include avoiding all of the potential problems and issues that have been described while not adding any major cost or complication to the process. Advantageously, methods and systems for layer transfer preparation by laser-induced defect generation may be employed to introduce a minimal amount of energy into the delicate growth layers of the semiconductor article while still having the technical effect of cleanly, efficiently, and gently releasing the desired layers involved in the layer transfer. Another technical effect of the finished product is then that any risk of delamination or other issues to which hybrid semiconductor articles (e.g., involving silicon-based and sapphire-based elements) are prone may be reduced or eliminated. Accordingly, various types of substrates with different transparency properties (e.g., sapphire, silicon, and / or other substrate material) may be selected for use as may best sen e a particular implementation, giving the fabricationprocess additional flexibility.

[0030] Various implementations will now be described in more detail with reference to the figures. It will be understood that particular implementations described below are provided as non-limiting examples and may be applied in various situations. Additionally, it will be understood that other implementations not explicitly described herein may also fall within the scope of the claims set forth below. Systems and methods described herein for layer transfer preparation of semiconductor articles by laser-induced defect generation may result in any or all of the technical effects mentioned above, as well as various additional effects and benefits that will be described and / or made apparent below.

[0031] FIG. 1 shows illustrative aspects of an example implementation of a semiconductor article 100 at different times ("Time TL” "‘Time T2,” and ‘Time T3”) during a process of layer transfer preparation and, then, layer transfer in accordance with principles described herein. In each of the illustrations of semiconductor article 100 in FIG. 1 (as well as in other figures below), a cross-section of several layers of semiconductor article 100 is shown in part. A broken-line effect on left and right edges of the cross-sectional views is shown to represent that the illustrated layers may continue to the right and / or to the left to constitute the entire semiconductor article 100, which may be, for instance, an entire w afer, a die or other portion of a w afer, or another suitable semiconductor article. It w ill be understood that principles illustrated and described in relation to the relatively small portion of semiconductor article 100 shown in each figure may also apply in a similar way to the remainder of the semiconductor article. It will also be understood that figures herein depicting the various layers and / or aspects thereof are not necessarily drawn to scale, nor is every layer that may be part of the semiconductor article necessarily shown.

[0032] Semiconductor article 100 will be understood to represent a donor or growth article that may be used to fabricate (grow') components that are later to be transferred to a separate semiconductor article. For example, semiconductor article 100 may be a growth wafer configured for epitaxial fabrication of microLED components that are intended, ultimately, to be transferred to a receiver or carrier wafer that includes, for example, backplane circuitry for the microLED components. Certain features of semiconductor article 100 are illustrated at Time Tl, which will be understood to represent a snapshot of the cross section of the semiconductor article during layer transfer preparation that is being performed by laser-induced defect generation. More particularly, semiconductor article 100 is shown to include a starting substrate 102, a growth substrate layer 104 deposited on starting substrate 102, and an epitaxial layer 106 deposited on growth substrate layer 104.

[0033] As shown, the various layers of semiconductor article 100 are layered closely together in a serial fashion, one layer deposited directly on top of another, with the two sides of the article labeled in accordance with the function of that side. Specifically, a substrate side 108-S (‘S’ for substrate) is labeled on the bottom of the stack (given the way semiconductor article 100 is oriented in FIG. 1) or on what will be considered the backside of the article. Substrate side 108-S, as shown, corresponds to starting substrate 102. A growth side 108-G (‘G’ for growth) is then labeled on the top of the stack (in accordance with the orientation of semiconductor article 100 in FIG. 1) or on what will be considered the frontside of the article. Growth side 108-G, as shown, corresponds to the layers where lithographic processing may be performed and various layers of material may be grown, applied, or otherwise deposited.

[0034] As will be described in more detail below, starting substrate 102 could be a silicon substrate, growth substrate layer 104 could be grown on the silicon as a GaN growth substrate, and epitaxial layer 106 could be grown on the GaN grow th substrate as an InGaN layer with varying levels of indium doping to form LEDs of different colors (e.g., red, green, blue, etc.). As mentioned, additional layers not explicitly shown in FIG. 1 (e.g., a metal layer with interconnections for LEDs implemented by epitaxial layer 106, etc.) may also be included such as above epitaxial layer 106 on the growth side 108-G.

[0035] A laser 110-1 is shown at Time T1 to be focusing laser light 112 to generate a defect 114 at a focal point within growth substrate layer 104. This defect 114 is shown to be included in a pattern 116 of defects that laser 110-1 is in the middle of generating at Time T1. More particularly, as shown, the pattern 116 of defects being generated within grow th substrate layer 104 may be induced by laser 110-1 (and by laser light 112 in particular) as laser 110-1 operates from the growth side 108-G of semiconductor article 100 (that corresponds to epitaxial layer 106 and is opposite starting substrate 102 and substrate side 108-S).

[0036] To generate defect 114 and the other defects in pattern 116, laser 110-1 may be configured to emit light 112 with a photon energy less than a bandgap associated with epitaxial layer 106. For example, if epitaxial layer 106 is implemented by InGaN material, laser 110-1 may be implemented by a laser with a wavelength less than about 1030 nanometers (nm), for which the InGaN material would be effectively transparent (due to the bandgap of InGaN). In one example, laser 110-1 may have a wavelength of about 800 nm to penetrate through quantum (e.g.. InGaN) epilayers. With this photon energy, laser light 112 may also tend to pass through growth substrate layer 104 (e.g., a GaN layer in this example,which would also be transparent to light with this photon energy). In other examples, laser 110-1 could be a UV laser with an even shorter wavelength.

[0037] As used herein, the bandgap associated with epitaxial layer 106 (which the photon energy of laser light 112 may be less than so as to pass through epitaxial layer 106) may refer to any of several bandgaps that may be present in epitaxial layer 106 (e.g., depending on the amount of doping that has been performed at a local area within the layer). For example, as mentioned above and as will be shown and described in more detail below, the growth wafer of semiconductor article 100 may include an array of microLED components including: 1) red components formed within epitaxial layer 106 and associated with a first bandgap; 2) green components formed within epitaxial layer 106 and associated with a second bandgap; and 3) blue components formed within epitaxial layer 106 and associated with a third bandgap. In this example, the photon energy of laser light 112 may therefore be less than each of the first bandgap, the second bandgap, and the third bandgap. In this way, regardless of the color of a microLED component implemented at any local area of epitaxial layer 106, the growth layers of semiconductor article 100 (i.e. , both growth substrate layer 104 and epitaxial layer 106) may be transparent to laser light 112 so that laser 110-1 will not inadvertently damage or interact with the intricate structures implemented within the epitaxial layer 106.

[0038] Despite this transparency, however, light processing by optical devices or other suitable elements of a fabrication system (not explicitly shown) may operate laser 110-1 in a manner that focuses the energy of laser light 1 12 at a focal point within grow th substrate layer 104. In this way, the energy of laser light 112 may be directed (i.e., focused) to accumulate and / or become concentrated at predetermined focal points (e.g., points at a safe depth beyond epitaxial layer 106 and within growth substrate layer 104). This focusing of laser light 112 may allow the energy within the light to interact with the material (e.g., the GaN material in this example) to generate the pattern 116 of defects (including defect 114) even given the material’s bandgap and the low er photon energy of the laser.

[0039] While it may theoretically be possible to generate defects so close to one another within growth substrate layer 104 as to create a continuous plane of defects that would fully detach epitaxial layer 106 (and a portion of growth substrate layer 104) from the rest of growth substrate layer 104 and starting substrate 102, it may be generally preferable during layer transfer preparation to avoid this full separation. Rather, as shown by pattern 116, the pattern of defects may be specifically configured so that sufficient growth substrate material remains between defects of the pattern of defects to prevent detachment of epitaxiallayer 106 from starting substrate 102 during processing of semiconductor article 100 and prior to a layer transfer being purposefully invoked. In other words, as shown, it may be desirable for pattern 116 to position respective defects (such as defect 114) close enough to one another to facilitate a clean and efficient detachment when it comes time for the layer transfer (described below), while also being far enough from one another that there remains sufficient structure to hold the layers together during further processing of semiconductor article 100 (e.g., through stages of etching, metal deposition of electrical contacts, etc.) prior to layer transfer.

[0040] As mentioned above, principles of layer transfer preparation described herein may be thought of as a two-dimensional (planar) analog to a one-dimensional (linear) perforation that connects, for example, a card to a sheet from which it is intended to be tom away. Specifically, just as the example perforation may be configured to hold the card in place sufficiently that it does not become detached on its own (while still facilitating detachment of the card when it is intended to be detached), so too may the pattern 116 of defects induced by laser 110-1 be configured to hold epitaxial layer 106 in place sufficiently that it does not become delaminated or inadvertently detached before a layer transfer is to be performed (while still facilitating such a layer transfer when the time arrives that such is desired).

[0041] At Time T2, a snapshot is shown for when the layer transfer preparation by laser-induced defect generation is complete and an actual layer transfer of epitaxial layer 106 is underway. For example, as will be described in more detail below, subsequent to generating the pattern 116 of defects (including defect 114), semiconductor article 100 may be aligned with an additional semiconductor article (e.g., a microLED backplane wafer including circuitry configured to drive microLED components, not shown in FIG. 1) with growth side 108-G of semiconductor article 100 facing the additional semiconductor article. An additional laser 110-2 may then be positioned, as shown, to operate from substrate side 108-S of semiconductor article 100 (i.e., opposite grow th side 108-G where laser 110-1 was positioned). For example, additional laser 110-2 may be different from laser 110-1 since, rather than needing to pass through epitaxial layer 106 and growth substrate layer 104. laser light 118 from laser 110-2 may need to pass through starting substrate 102 and growth substrate layer 104 to introduce and expand a crack 120 that propagates through pattern 116 of defects to help detach epitaxial layer 106 from starting substrate 102 at a defect plane that has been prepared.

[0042] To this end, additional laser 110-2 may be configured to emit light 118 havingan additional photon energy that is different from the photon energy of light 112 emitted by laser 110-1. This additional photon energy may be less than a bandgap associated with starting substrate 102 so that light 118 may pass through starting substrate 102 (i.e., so that starting substrate 102 will be transparent to laser light 118). For example, laser 110-2 may employ a wavelength greater than about 1030 nm (e.g., an IR or near-IR (NIR) wavelength). With this wavelength, starting substrate 102 may be constructed from a material such as silicon (which is transparent to light with wavelengths longer than 1030 nm). and need not be limited to sapphire or other materials that may be associated with technical problems described above.

[0043] When properly tuned to a suitable wavelength, laser light 118 of additional laser 110-2 may pass through a starting substrate 102 formed from silicon to then focus on a defect such as defect 114. For example, laser light 118 may be applied in short pulses and gentle bursts of pulses until heat introduced into a particular defect (e.g., defect 114) begins to cause a crack 120 to expand from defect to defect (as illustrated by the arrow under crack 120) along a predefined defect plane associated with pattern 116. When crack 120 expands over the entire predefined defect plane, epitaxial layer 106 and a part of grow th substrate layer 104 above the defect plane (i.e., above the pattern 116 of defects) may detach from starting substrate 102 and the remainder of growth substrate layer 104.

[0044] To illustrate, FIG. 1 show s, at Time T3, a detachment 122 of a transfer portion 124-1 of semiconductor article 100 from a substrate portion 124-2 of semiconductor article 100. More particularly, as shown, transfer portion 124-1 includes epitaxial layer 106 (where the microLEDs may be implemented, as will be described and illustrated in more detail below) and part of growth substrate layer 104 (e.g., enough of growth substrate layer 104 to ensure that epitaxial layer 106 is fully intact, though this portion of growth substrate layer 104 may later be removed after the layer transfer is complete). As further shown, substrate portion 124-2 includes the remainder of growth substrate layer 104 and starting substrate 102.

[0045] It will be understood that creating transfer portion 124-1 may have been the primary objective of fabricating semiconductor article 100, such that transfer portion 124-1 may be considered the main product of the fabrication with substrate portion 124-2 being considered a byproduct of the process. Indeed, in some examples, substrate portion 124-2 may be discarded after the layer transfer (including detachment 122) is complete. In other examples, however, substrate portion 124-2 may be retained and prepared for reuse (e.g., to grow another set of microLEDs on a new set of growth layers). For example, substrate portion 124-2 may go through a cleaning process to remove what is left of growth substratelayer 104 and prepare starting substrate 102 to be reused as a starting substrate for a new growth wafer like semiconductor article 100.

[0046] FIG. 2 shows an illustrative fabrication system 200 configured to perform layer transfer preparation of a semiconductor article by laser-induced defect generation and layer transfer of the prepared semiconductor article in accordance with principles described herein. For example, fabrication system 200 may be used to perform or facilitate the layer transfer preparation illustrated above with semiconductor article 100. as well as the layer transfer itself (in which the detached transfer portion 124-1 illustrated above is attached to an additional semiconductor article as described and illustrated in more detail below).

[0047] As shown, this implementation of fabrication system 200 may include the first laser 110-1, the additional laser 110-2. and one or more processors 202 that may be communicatively coupled to the lasers and to a memory' 204. Processors 202 may be configured to execute instructions 206 stored within memory 204 to perform any of a set of processes 208 encoded by instructions 206. As described above, laser 110-1 is shown to have a relatively short wavelength (“Shorter Wavelength”) so as to pass through epitaxial layer 106 and generate defects in growth substrate layer 104. For example, as mentioned, laser 110-1 may be configured to emit light (e.g., laser light 112) having a photon energy less than a bandgap associated with epitaxial layer 106 of semiconductor article 100. In contrast, additional laser 110-2 is shown to have a relatively long wavelength (“Longer Wavelength”) so as to pass through silicon of starting substrate 102 to generate and expand a crack that connects defects that were previously generated in growth substrate layer 104 using laser 110-1. For example, laser 110-2 may be configured to emit light (e.g., laser light 118) having an additional photon energy different from the photon energy of light emitted by laser 110-1 and less than a bandgap associated with starting substrate 102.

[0048] Processors 202 may represent any suitable general-purpose processors (e.g., central processing units (CPUs), microprocessors, etc.), special-purpose processors (e.g., field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.), or other suitable processing resources. Lasers 110-1 and 110-2 may be communicatively coupled to. and controlled by, processors 202 in various respects. For example, based on instructions 206 loaded from memory 204, processors 202 may control the positioning and / or alignment of lasers 110-1 and 110-2 with respect to a semiconductor article (e.g., to align and position laser 110-1 to generate a particular defect, to later align and position additional laser 110-2 to expand that particular defect, etc.). Additionally, based on the instructions 206, processors 202 may control operations of the lasers such as by pulsing the lasers on and off,focusing the lasers to concentrate their energy at certain focal points (e.g., a focal point of a particular defect, etc.), and so forth.

[0049] Along with exerting control and / or influence on lasers 110-1 and 110-2, fabrication system 200 (and processors 202 in particular) may also exert control and / or influence on the positioning of semiconductor articles such as semiconductor article 100 (serving as a donor article) and / or an additional semiconductor article (serving as a carrier or receiver article). For example, as will be described in more detail below, fabrication system 200 may be configured to align different semiconductor articles with one another as part of a layer transfer in which microLED components are transferred from a grow th wafer (e.g., semiconductor article 100) to one or more backplane wafers configured to host the microLED components.

[0050] To illustrate the types of processes 208 that processors 202 may perform, FIGS. 3A-3B show flow diagrams for two illustrative methods for a layer transfer between semiconductor articles in accordance with principles described herein. More particularly, FIG. 3A shows a method 300-A with operations 302-306 that implement layer transfer preparation of a growth semiconductor article such as semiconductor article 100, while FIG. 3B shows a method 300-B with operations 308-316 that use the prepared semiconductor article to complete the layer transfer from the growth semiconductor article to a carrier semiconductor article. It will be understood that methods 300-A and 300-B, as well as other similar methods described herein or that may implement variations in accordance with principles described herein may be encoded in instructions 206 to serve as processes 208 performed by fabrication system 200.

[0051] While FIGS. 3A-3B show' illustrative operations according to specific implementations, it will be understood that other implementations of these methods may omit, add to, reorder, and / or modify any of operations that are explicitly represented in FIGS. 3A-3B. Additionally, while operations shown in these figures are illustrated with arrows suggestive of a sequential order of operation, it will be understood that some or all of the operations of methods 300-A and 300-B may be performed concurrently (e.g., in parallel) with one another. Each of the operations of these methods will now be described in more detail as the operations may be performed by a system such as fabrication system 200. Additionally, further detail related to certain of the operations w ill be given w ith reference to FIGS. 4, 5, 6A-6B. and 7A-7B in the following description of methods 300-A and 300-B.

[0052] At operation 302 of method 300-A, the system may position a laser (e.g., laser 1 10-1) to operate from a growth side of a semiconductor article. For example, likesemiconductor article 100 illustrated above, the semiconductor article may include a starting substrate (e.g., starting substrate 102), a growth substrate layer deposited on the starting substrate (e.g., growth substrate layer 104), and an epitaxial layer deposited on the growth substrate layer (e.g., epitaxial layer 106). Accordingly, the growth side (e.g., growth side 108- G) at which the laser is positioned may correspond to the epitaxial layer and may be opposite the starting substrate (as shown, for example, at Time T1 in FIG. 1).

[0053] At operation 304 of method 300-A, the system may configure the laser to emit light (e.g., laser light 1 12) to a focal point within the growth substrate layer. As has been described, the light emitted by this laser may have a photon energy7less than a bandgap associated with the epitaxial layer. For example, different parts of the epitaxial layer may have different amounts of doping (e.g., different amounts of indium deposited within the gallium nitride to form quantum layers associated with different colors of LEDs), such that this bandgap that the photon energy is less than may refer to the lowest bandgap that the materials within the epitaxial layer may have. In this way, the light may pass through the epitaxial layer (regardless of what color of microLED may have been constructed at any given locality7where the laser is positioned) without interacting with delicate structures that have been grown within the layer.

[0054] At operation 306 of method 300-A, the system may operate the laser to generate a defect at the focal point within the growth substrate layer. For example, the system may cause the laser to be focused (e.g., using optics that are also under control of the system) to become concentrated at the focal point. In this way, even though the photon energy may be low enough that the epitaxial and grow th substrate layers are transparent to the laser light, the focusing of the laser may allow the energy to accumulate and build at one spot (i.e., at the focal point) to thereby interact with the growth substrate (e.g., GaN) and generate the defect.

[0055] To illustrate the types of defects that may be generated by the operation of the laser at operation 306, FIG. 4 shows illustrative defects that may be generated within a growth substrate layer of a semiconductor article in accordance with principles described herein. As show n in FIG. 4, this implementation of semiconductor article 100 includes a starting substrate 102 that is constructed of silicon (Si), a growth substrate layer 104 that is constructed of gallium nitride (GaN), and an epitaxial layer 106 that is constructed of indium gallium nitride (InGaN). In a breakout window 402, FIG. 4 shows two defects 114-1 and 114- 2 in closeup. As shown, the generating of defects 114-1 and 114-2 within the GaN material of growth substrate layer 104 may cause the GaN to separate into its gallium (Ga) and nitrogen (N2) constituents. It will be understood that defects 114-1 and 114-2 may be similar to theother defects of the pattern 116 of defects that may be introduced throughout a defect plane in the growth substrate layer 104.

[0056] As shown, this defect plane (including all the defects of pattern 116) may be created slightly below epitaxial layer 106 so that there may be minimal risk that any defect accidentally damages epitaxial layer 106 while also leaving a minimal amount of GaN material to remove or strip off after the layer transfer to expose the microLED components implemented within the epitaxial layer 106. For example, the defect plane of pattern 116 may be approximately 100 nm below epitaxial layer 106 in one example.

[0057] These principles are further illustrated by FIG. 5, which shows illustrative details of epitaxial layer 106. As shown in a breakout window 502 that shows a portion of epitaxial layer 106 and its interface with growth substrate layer 104, the InGaN of epitaxial layer 106 may be deposited on the GaN of grow th substrate layer 104 by doping the GaN with a certain ratio of indium to gallium for different portions. For example, GaN above the dashed line in breakout window 502 may be doped, as shown, with different amounts of indium to form a red quantum well ( ( R)") associated with a red microLED component, a green quantum well ('‘(G)’’) associated with a green microLED component, and a blue quantum w ell (“(B)”) associated with a blue microLED component. In each of these cases, the InGaN of epitaxial layer 106 w ill be understood to be an alloy of the GaN of growth substrate layer 104 and indium nitride (InN) that is deposited thereon. However, the bandgap of the InGaN in these different areas (R), (G). and (B) may be tuned to produce the desired colors by changing the concentration of InN. For example, a higher indium concentration may result in a narrow er bandgap associated with light having a longer wavelength (e.g., red light), while a lower indium concentration may result in a wider bandgap associated with light having a shorter wavelength (e.g., green or blue light).

[0058] Along with layers 104 and 106, semiconductor article 100 may further include one or more additional layers that are incorporated into (or deposited above) epitaxial layer 106. For example, breakout window 502 in FIG. 5 further shows that an additional metal layer 504 may be deposited on epitaxial layer 106. While metal layer 504 is not drawn with great detail in FIG. 5, it will be understood that additional metal layer 504 may represent electrical contacts and other such functional aspects that are fabricated on the microLED components to prepare the components to integrate with the backplane circuitry' when the layer transfer is complete. As such, while metal layer 504 is shown to be on the very front (i.e., the growth side 108-G) of semiconductor article 100, it will be understood that, subsequent to the layer transfer and the removal of any remnants of growth substrate layer104, metal layer 504 may interact with circuitry of the backplane semiconductor article while the red. green, and blue portions of epitaxial layer 106 shown in breakout window 502 may be exposed (or perhaps covered with a transparent protective layer) to allow light to be emitted from the microLED components in the finished product.

[0059] Returning to FIG. 3A, along with focusing the laser to concentrate energy at the depth of the defect plane (and, more particularly, at a focal point associated with one of the defects such as defect 114-1 or 1 14-2), the operating of the laser at operation 306 may also involve powering the laser on at the appropriate time and then turning it back off before the defect grows larger than desired or unwanted damage is done. In other words, operation 306 may include pulsing the laser for a predetermined amount of time needed to generate the defect once the laser is properly positioned and focused. While operation 306 refers specifically to a particular defect that is generated at a particular focal point within the growth substrate layer, it will be understood that method 300-A may be performed repeatedly to fully prepare the semiconductor article for the layer transfer. As such, the particular defect referenced by operation 306 will be understood to be just one defect (e.g., defect 114-1 or 114-2) included in a pattern of defects (e.g.. pattern 116) induced by the laser.

[0060] Turning to FIG. 3B, method 300-B is shown to be performed after a semiconductor article (e.g., semiconductor article 100) has been prepared for a layer transfer, such as by performing method 300-A a number of times to generate the pattern of defects within the semiconductor article ("Perform Method 300-A”). After this layer transfer preparation by laser-induced defect generation is complete (i.e., subsequent to generating the pattern of defects by repeated performances of method 300-A), method 300-B shows that various operations 308-316 may be performed to complete the layer transfer.

[0061] At operation 308 of method 300-B, the system may align the semiconductor article with an additional semiconductor article. For example, a growth wafer configured for epitaxial fabrication of microLED components (e.g., semiconductor article 100) may be positioned, with respect to a microLED backplane wafer (e.g., the additional semiconductor article) that includes circuitry configured to drive the microLED components, to align one or more microLED components to the circuitry on the backplane wafer that is configured to drive the components. To this end, the growth side (e.g., growth side 108-G) of the semiconductor article may face the additional semiconductor article during the alignment at operation 308.

[0062] The alignment of operation 308 is illustrated for a first type of scenario in FIGS. 6A-6B and for a second type of scenario in FIGS. 7A-7B. More particularly, FIGS.6A-6B show illustrative aspects of a localized layer transfer from semiconductor article 100 to the additional semiconductor article, while FIGS. 7A-7B show illustrative aspects of a full layer transfer from semiconductor article 100 to the additional semiconductor article in accordance with principles described herein. FIGS. 6A and 7A illustrate their respective scenarios (the localized layer transfer and the full layer transfer, respectively) in a similar manner as described above at length in the example of FIG. 1. Specifically, each of these figures shows Times Tl. T2. and T3, where Time T1 represents the semiconductor article after layer transfer preparation (with the entire pattern 116 in place, in contrast to Time Tl in FIG. 1), Time T2 represents the semiconductor article when the second laser is being operated to help release the layers being transferred, and Time T3 represents the actual detachment of the layers. Due to space constraints, starting substrate 102 is labeled as SS 102 in FIGS. 6A and 7A, growth substrate layer 104 is labeled as GSL 104 (or, when split at Time T3, as GSL 104-1 and GSL 104-2), and epitaxial layer 106 is labeled as EL 106. FIGS. 6B and 7B then illustrate the respective detachments in the context of the additional semiconductor article to thereby illustrate the complete layer transfers.

[0063] The difference between the localized layer transfer scenario illustrated by FIGS. 6A-6B and the full layer transfer scenario illustrated by FIGS. 7A-7B is that the semiconductor article 100 in the localized layer transfer is shown to be etched such that individual components may be transferred into different locations, while the full layer transfer includes no such separation. More particularly, as shown in FIG. 6A. etching 602 has been performed (e.g., as part of the layer transfer preparation) so that localized components (e.g., individual microLED components or individual pixel components including small groups of microLEDs such as the red, green, and blue components used to form a white pixel) may be released and deposited separately from other components grown immediately adjacent. This would allow, for example, two microLED components that were grown immediately next to one another to be released from the growth wafer at different times so that the components could be installed at two non-adjacent locations on the backplane wafer. Like the example described above in relation to FIG. 1, the implementation of semiconductor article 100 in FIG. 7A is shown to include no such etchings, such that the full epitaxial layer 106 may be released at once and microLED components fabricated near one another ill continue to have the same relationship after being installed on the backplane wafer.

[0064] The alignment of operation 308 is illustrated in FIG. 6B for the localized layer transfer scenario. More particularly, FIG. 6B shows an alignment 600-1 of the semiconductor article 100 with an additional semiconductor article 610 that allows for a first microLEDcomponent 608-1 to be transferred to a first location 612-1 on additional semiconductor article 610 (e.g., a location where driver circuitry intended for the microLED component 608-1 has been fabricated). FIG. 6B further shows an alignment 600-2 of the semiconductor article 100 with additional semiconductor article 610 to allow for a second microLED component 608-2 to be transferred to a second location 612-2 on additional semiconductor article 610 (e.g., a location where driver circuitry intended for the microLED component 608-2 has been fabricated). FIG. 6B further shows an alignment 600-3 of the semiconductor article 100 with additional semiconductor article 610 to allow for a third microLED component 608-3 to be transferred to a third location 612-3 on additional semiconductor article 610 (e.g., a location where driver circuitry intended for the microLED component 608-3 has been fabricated).

[0065] The alignment of operation 308 is also illustrated in FIG. 7B for the full layer transfer scenario. More particularly, FIG. 7B shows an alignment 700 of the semiconductor article 100 with an additional semiconductor article 710 that allows for an array of nonseparated microLED components 708 (e.g., including, specifically, a microLED component 708-1, a microLED component 708-2. and a microLED component 708-3 in the portion show n in FIG. 7B) to be transferred to additional semiconductor article 710 such that respective locations 712-1, 712-2, and 712-3 on additional semiconductor article 710 (e.g., locations where driver circuitry intended for the respective microLED components 708 have been fabricated) align with the corresponding microLED components 708. Unlike with FIG. 6B, where the alignment changed prior to the layer transfer of each individual component, FIG. 7B shows that alignment 700 does not change since the entire layer is transferred in full, rather than in individual segments.

[0066] Returning to FIG. 3B, at operation 310 of method 300-B, the system may position an additional laser (e.g., additional laser 110-2) to operate from a substrate side (e.g., substrate side 108-S) of the semiconductor article opposite the growth side. This positioning will allow the growth side of the semiconductor article to be placed directly flush with the circuitry of the additional semiconductor article (without the laser in between, as the first laser 110-1 would be given its positioning at operation 302). In other words, after the pattern of defects has been generated, the first laser may be removed from the process so that the growth side of the semiconductor article may be applied directly to the additional semiconductor article for the layer transfer.

[0067] The positioning of the additional laser is shown in FIG. 6A at Time T1 for the localized layer transfer scenario, and in FIG. 7A at Time T1 for the full layer transferscenario. Similarly as described above in relation to FIG. 1, additional laser 110-2 is shown in both of these examples to be positioned on substrate side 108-S of semiconductor article 100 so that growth side 108-G may be attached to the additional semiconductor article (e.g., to additional semiconductor article 610 as shown in FIG. 6B and to additional semiconductor article 710 as shown in FIG. 7B).

[0068] Returning to FIG. 3B, at operation 312 of method 300-B, the system may produce the layer transfer for a portion of the semiconductor article. This portion may be different in different scenarios, as has been described. For example, in the localized layer transfer scenario of FIGS. 6A-6B, the portion of the semiconductor article being transferred is limited to a local area between etchings 602 (e.g.. an individual microLED component; an individual pixel component that includes at least one red, one blue, and one green microLED component; etc.). In contrast, in the full layer transfer scenario of FIG. 7A-7B, the portion of the semiconductor article being transferred may cover the entirety of the semiconductor article (e.g., the full epitaxial layer 106 of the entire growth wafer or of at least of a particular die or other distinct portion of the growth wafer). As shown in FIG. 3B, operation 312 may include operations 314 and 316. or, in other words, may be achieved by performing operations 314 and 316.

[0069] At operation 314 of method 300-B, the system may operate the additional laser to expand the defect generated at operation 306 to detach, from the portion of the semiconductor article, the epitaxial layer and part of the growth substrate layer. To illustrate this operation for the localized layer transfer scenario, for instance, FIG. 6A shows, at Time T2, that additional laser 110-2 is operated to generate laser light 118 such that one defect is expanded to cause a crack 604 to connect the defect to additional defects of the pattern of defects within the portion of the semiconductor article. In other words, as shown in FIG. 6A. crack 604 may expand from defect to defect between the etchings 602 associated with the portion of the semiconductor article being transferred. As show n, while crack 604 may expand through each of the defects within this portion, however, the crack stops at etchings 602 so as to not disturb or release neighboring components. Indeed, at Time T3, FIG. 6A shows that a single microLED component 608 is released as part of a detachment 606 while other components remain attached to the semiconductor article 100.

[0070] To illustrate this operation for the full layer transfer scenario, FIG. 7A shows, at Time T2, that additional laser 110-2 is operated to generate laser light 118 such that one defect is expanded to cause a crack 704 to connect the defect to additional defects of the pattern of defects within the portion of the semiconductor article. In other words, as shown inFIG. 7A, crack 704 may expand from defect to defect throughout the full semiconductor article 100. Depending on the size of the semiconductor article and the pattern used for the defects (e.g., how close the defects are to one another etc.), it may be helpful to apply laser light 118 at several defects throughout the pattern to cause the full expansion of crack 704 to ultimately allow the entire epitaxial layer 106 (labeled as EL 106) and the corresponding part of the growth substrate layer 104 (labeled as GSL 104-1) to delaminate. Indeed, at Time T3, FIG. 7A shows that the full array of non-separated microLED components 708 is released as part of a detachment 706.

[0071] Returning to FIG. 3B, at operation 316 of method 300-B, the system may attach, to the additional semiconductor article, the epitaxial layer and the part of the growth substrate layer detached from the portion of the semiconductor article. Again, as mentioned above, this attachment may look different depending on what portion of the semiconductor article is at play (i.e., a localized portion or the full layer).

[0072] For the localized layer transfer scenario, FIG. 6B show s that the portion of the semiconductor article being attached for each alignment 600-1 through 600-3 includes an individual microLED component 608 (or an individual pixel containing multiple microLED components) fabricated on semiconductor article 100 at a particular pitch (i.e., the distance betw een elements or the inverse of the element density)- This particular pitch is shown to be significantly smaller than a final pitch used for the individual microLED component when attached to additional semiconductor article 610 (e.g.. the pitch of locations 612-1 through 612-3, which are shown to be farther apart than the microLED components 608-1 through 608-3 as fabricated on semiconductor article 100).

[0073] It is because of this pitch difference that distinct alignments 600-1 through 600-3 may be used for each layer transfer 614-1, 614-2 and 614-3 shown in FIG. 6B for each microLED component 608-1 through 608-3. Specifically, layer transfer 614-1 is shown to involve the detachment of microLED component 608-1 from semiconductor article 100 and its corresponding attachment to location 612-1 of additional semiconductor article 610. Layer transfer 614-2 is shown to involve the detachment of microLED component 608-2 from semiconductor article 100 and its corresponding attachment to location 612-2 of additional semiconductor article 610. Layer transfer 614-3 is shown to involve the detachment of microLED component 608-3 from semiconductor article 100 and its corresponding attachment to location 612-3 of additional semiconductor article 610.

[0074] While changing alignments are shown in FIG. 6B. however, it will be understood that many components 608 from the semiconductor article could be transferred tothe additional semiconductor article based on a single alignment. For instance, if the final pitch of the locations on the additional semiconductor article were ten times greater than the pitch of the components as fabricated on the semiconductor article, the articles could be aligned once and then every tenth component could be transferred across the entire article. A realignment could then be performed on the same or a different backplane semiconductor article (since the greater pitch may result in only one-tenth of the components fitting on a semiconductor article of the same size and the donor semiconductor article may therefore serve up to ten receiver semiconductor articles in this example).

[0075] In contrast, for the full layer transfer scenario, FIG. 7B shows that the full layers of semiconductor article 100 attached for alignment 700 include a plurality' of microLED components 708 fabricated on the semiconductor article at a particular pitch (i.e.. the distance between elements or the inverse of the element density). In this case, this particular pitch is shown to be equal to a final pitch used for the plurality of microLED components when attached to additional semiconductor article 610 (e.g., the pitch of locations 712-1 through 712-3, which are shown to be equally far apart as the microLED components 708-1 through 708-3 as fabricated on semiconductor article 100).

[0076] As a result of this pitch uniformity, FIG. 7B shows that the single alignment 700 is used for the single layer transfer 714 of microLED component 708 from semiconductor article 100 to additional semiconductor article 710. Specifically, layer transfer 714 is shown to involve the detachment of microLED component 708 from semiconductor article 100 and its corresponding attachment (with microLED components 708-1 through 708-3 aligning to their corresponding locations 712-1 through 712-3) to additional semiconductor article 710.

[0077] Various methods and processes described herein may be implemented at least in part as instructions embodied in a non-transitory computer-readable medium and executable by one or more computing devices. In general, a processor (e.g., a microprocessor) receives instructions, from a non-transitory computer-readable medium (e.g., a memory, etc.), and executes those instructions, thereby performing one or more operations such as the operations described herein. Such instructions may be stored and / or transmitted using any of a variety of known computer-readable media.

[0078] A computer-readable medium (also referred to as a processor-readable medium) includes any non- transitory' medium that participates in providing data (e.g., instructions) that may be read by a computer (e.g., by a processor of a computer). Such a medium may take many forms, including, but not limited to, non-volatile media, and / orvolatile media. Non-volatile media may include, for example, optical or magnetic disks and other persistent memory. Volatile media may include, for example, dynamic random-access memory (DRAM), which typically constitutes a main memory. Common forms of computer- readable media include, for example, a disk, hard disk, magnetic tape, any other magnetic medium, a compact disc read-only memory7(CD-ROM), a digital video disc (DVD), any other optical medium, random access memory (RAM), programmable read-only memory7(PROM), electrically erasable programmable read-only memory (EPROM), FLASH- EEPROM, any' other memory chip or cartridge, or any other tangible medium from which a computer can read.

[0079] FIG. 8 shows an illustrative computing system 800 that may be used to implement various devices and / or systems described herein. For example, computing system 800 may include or implement (or partially implement) systems such as fabrication system 200, any implementations thereof, any components thereof, and / or other devices used therewith.

[0080] As shown in FIG. 8, computing system 800 may include a communication interface 802, a processor 804, a storage device 806, and an input / output (I / O) module 808 communicatively connected via a communication infrastructure 810. While an illustrative computing system 800 is shown in FIG. 8, the components illustrated in FIG. 8 are not intended to be limiting. Additional or alternative components may be used in other embodiments. Components of computing system 800 shown in FIG. 8 will now be described in additional detail.

[0081] Communication interface 802 may be configured to communicate with one or more computing devices. Examples of communication interface 802 include, w ithout limitation, a wired network interface (such as a network interface card), a wireless network interface (such as a wireless network interface card), a modem, an audio / video connection, and any other suitable interface.

[0082] Processor 804 generally represents any ty pe or form of processing unit capable of processing data or interpreting, executing, and / or directing execution of one or more of the instructions, processes, and / or operations described herein. Processor 804 may direct execution of operations in accordance w ith one or more applications 812 or other computerexecutable instructions such as may be stored in storage device 806 or another computer- readable medium.

[0083] Storage device 806 may include one or more data storage media, devices, or configurations and may employ any ty pe, form, and combination of data storage mediaand / or device. For example, storage device 806 may include, but is not limited to, a hard drive, network drive, flash drive, magnetic disc, optical disc, RAM. dynamic RAM, other non-volatile and / or volatile data storage units, or a combination or sub-combination thereof. Electronic data, including data described herein, may be temporarily and / or permanently stored in storage device 806. For example, data representative of one or more executable applications 812 configured to direct processor 804 to perform any of the operations described herein may be stored within storage device 806. In some examples, data may be arranged in one or more databases residing within storage device 806.

[0084] I / O module 808 may include one or more I / O modules configured to receive user input and provide user output. One or more I / O modules may be used to receive input for a single virtual experience. I / O module 808 may include any hardware, firmware, software, or combination thereof supportive of input and output capabilities. For example, I / O module 808 may include hardware and / or software for capturing user input, including, but not limited to, a keyboard or key pad, a touchscreen component (e.g., touchscreen display), a receiver (e.g., an RF or infrared receiver), motion sensors, and / or one or more input buttons.

[0085] I / O module 808 may include one or more devices for presenting output to a user, including, but not limited to, a graphics engine, a display (e.g., a display screen), one or more output drivers (e.g., display drivers), one or more audio speakers, and one or more audio drivers. In certain embodiments, I / O module 808 is configured to provide graphical data to a display for presentation to a user. The graphical data may be representative of one or more graphical user interfaces and / or any other graphical content as may serve a particular implementation.

[0086] The following examples describe implementations of lay er transfer preparation of a semiconductor article by laser-induced defect generation in accordance with principles described herein.

[0087] Example 1 : A method comprising: positioning a laser to operate from a growth side of a semiconductor article that includes a starting substrate, a growth substrate layer deposited on the starting substrate, and an epitaxial layer deposited on the growth substrate layer, the growth side corresponding to the epitaxial layer and being opposite the starting substrate; configuring the laser to emit light to a focal point within the growth substrate layer, the light having a photon energy less than a bandgap associated with the epitaxial layer; and operating the laser to generate a defect at the focal point within the growth substrate layer, the defect included in a pattern of defects induced by the laser.

[0088] Example 2: The method of any of the preceding examples, wherein thesemiconductor article is a grow th wafer configured for epitaxial fabrication of microLED components.

[0089] Example 3: The method of any of the preceding examples, wherein the growth wafer includes an array of microLED components including: red components formed within the epitaxial layer and associated with a first bandgap; green components formed within the epitaxial layer and associated with a second bandgap; and blue components formed within the epitaxial layer and associated with a third bandgap; wherein the photon energy is less than each of the first bandgap, the second bandgap, and the third bandgap.

[0090] Example 4: The method of any of the preceding examples, further comprising: aligning, subsequent to generating the partem of defects, the semiconductor article with an additional semiconductor article, the growth side of the semiconductor article facing the additional semiconductor article; positioning an additional laser to operate from a substrate side of the semiconductor article opposite the growth side; and producing a layer transfer for a portion of the semiconductor article by: operating the additional laser to expand the defect to detach, from the portion of the semiconductor article, the epitaxial layer and part of the growth substrate layer, and attaching, to the additional semiconductor article, the epitaxial layer and the part of the growth substrate layer detached from the portion of the semiconductor article.

[0091] Example 5: The method of any of the preceding examples, wherein the additional laser is configured to emit light having an additional photon energy, the additional photon energy being different from the photon energy of the light emitted by the laser and being less than a bandgap associated with the starting substrate.

[0092] Example 6: The method of any of the preceding examples, wherein the additional semiconductor article is a microLED backplane wafer including circuitry configured to drive microLED components.

[0093] Example 7: The method of any of the preceding examples, wherein: the portion of the semiconductor article includes a plurality of microLED components fabricated on the semiconductor article at a particular pitch; the operating the additional laser to expand the defect causes a crack to connect the defect to additional defects of the pattern of defects within the portion of the semiconductor article; and the particular pitch is equal to a final pitch used for the plurality of microLED components when attached to the additional semiconductor article.

[0094] Example 8: The method of any of the preceding examples, wherein: the portion of the semiconductor article includes an individual microLED component fabricatedon the semiconductor article at a particular pitch; the operating the additional laser to expand the defect causes a crack to connect the defect to additional defects of the pattern of defects within the portion of the semiconductor article; and the particular pitch is smaller than a final pitch used for the individual microLED component when attached to the additional semiconductor article.

[0095] Example 9: The method of any of the preceding examples, wherein: the starting substrate is constructed of silicon (Si); the growth substrate layer is constructed of gallium nitride (GaN); and the epitaxial layer is constructed of indium gallium nitride (InGaN).

[0096] Example 10: The method of any of the preceding examples, wherein the semiconductor article further includes an additional metal layer deposited on the epitaxial layer.

[0097] Example 11 : The method of any of the preceding examples, wherein the pattern of defects is configured so that sufficient growth substrate material remains between defects of the pattern of defects to prevent detachment of the epitaxial layer from the starting substrate during processing of the semiconductor article and prior to a layer transfer being produced.

[0098] Example 12: A semiconductor article comprising: a starting substrate; a growth substrate layer deposited on the starting substrate; an epitaxial layer deposited on the growth substrate layer; and a pattern of defects generated within the growth substrate layer, the pattern of defects induced by a laser operating from a growth side of the semiconductor article that corresponds to the epitaxial layer and is opposite the starting substrate; wherein the laser is configured to emit light with a photon energy' less than a bandgap associated with the epitaxial layer, the light being focused to a focal point within the growth substrate layer.

[0099] Example 13: The semiconductor article of any of the preceding examples, implemented as a growth wafer configured for epitaxial fabrication of microLED components.

[0100] Example 14: The semiconductor article of any of the preceding examples, w herein the growth wafer includes an array of microLED components including: red components formed within the epitaxial layer and associated with a first bandgap; green components formed within the epitaxial layer and associated with a second bandgap; and blue components formed within the epitaxial layer and associated with a third bandgap; wherein the photon energy is less than each of the first bandgap. the second bandgap, and the third bandgap.

[0101] Example 15: The semiconductor article of any of the preceding examples, wherein: the starting substrate is constructed of silicon (Si); the growth substrate layer is constructed of gallium nitride (GaN); and the epitaxial layer is constructed of indium gallium nitride (InGaN).

[0102] Example 16: The semiconductor article of any of the preceding examples, wherein the pattern of defects is configured so that sufficient growth substrate material remains between defects of the pattern of defects to prevent detachment of the epitaxial layer from the starting substrate during processing of the semiconductor article and prior to a layer transfer being produced.

[0103] Example 17: A system comprising: a laser configured to emit light having a photon energy less than a bandgap associated with an epitaxial layer of a semiconductor article that includes a starting substrate, a growth substrate layer deposited on the starting substrate, and the epitaxial layer deposited on the growth substrate layer; and one or more processors communicatively coupled to a memory and configured to execute instructions stored within the memory to perform a process comprising: positioning the laser to operate from a growth side of the semiconductor article, the growth side corresponding to the epitaxial layer and being opposite the starting substrate; configuring the laser to emit the light to a focal point within the grow th substrate layer; and operating the laser to generate a defect at the focal point within the growth substrate layer, the defect included in a pattern of defects induced by the laser.

[0104] Example 18: The system of any of the preceding examples, further comprising an additional laser and wherein the process further comprises: aligning, subsequent to generating the pattern of defects, the semiconductor article with an additional semiconductor article, the growth side of the semiconductor article facing the additional semiconductor article; positioning the additional laser to operate from a substrate side of the semiconductor article opposite the growth side; and producing a layer transfer for a portion of the semiconductor article by: operating the additional laser to expand the defect to detach, from the portion of the semiconductor article, the epitaxial layer and part of the growth substrate layer, and attaching, to the additional semiconductor article, the epitaxial layer and the part of the growth substrate layer detached from the portion of the semiconductor article.

[0105] Example 19: The system of any of the preceding examples, wherein: the additional laser is configured to emit light having an additional photon energy', the additional photon energy being different from the photon energy of the light emitted by the laser and being less than a bandgap associated with the starting substrate; the semiconductor article is agrowth wafer configured for epitaxial fabrication of an array of microLED components; and the additional semiconductor article is a microLED backplane wafer including circuitry configured to drive the array of microLED components.

[0106] Example 20: The system of any of the preceding examples, wherein: the portion of the semiconductor article includes an individual microLED component fabricated on the semiconductor article at a particular pitch; the operating the additional laser to expand the defect causes a crack to connect the defect to additional defects of the pattern of defects within the portion of the semiconductor article; and the particular pitch is smaller than a final pitch used for the individual microLED component when attached to the additional semiconductor article.

[0107] Various implementations of the systems and techniques described herein can be realized in digital electronic circuitry, integrated circuitry, specially designed ASICs (application specific integrated circuits), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which may be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0108] A number of implementations have been described. Nevertheless, it w ill be understood that various modifications may be made w ithout departing from the spirit and scope of the description and claims. In addition, the logic flows depicted in the figures do not require the particular order shown, or sequential order, to achieve desirable results. In addition, other steps may be provided, or steps may be eliminated, from the described flows, and other components may be added to, or removed from, the described systems. Accordingly, other implementations are within the scope of the following claims.

[0109] Specific structural and functional details disclosed herein are merely representative for purposes of describing example implementations. Example implementations, however, may be embodied in many alternate forms and should not be construed as limited to only the implementations set forth herein.

[0110] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. A first element could be termed a second element, and. similarly, a second element could be termed a first element, without departing from the scope of the implementations of the disclosure. As used herein.the term and / or includes any and all combinations of one or more of the associated listed items.

[0111] The terminology used herein is for the purpose of describing particular implementations only and is not intended to be limiting of the implementations. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and / or “including,” when used in this specification, specify the presence of the stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0112] It will be understood that when an element is referred to as being “coupled,” “connected,” or “responsive” to, or “on,” another element, it can be directly coupled, connected, or responsive to, or on, the other element, or intervening elements may also be present. In contrast, when an element is referred to as being “directly coupled,” “directly- connected,” or “directly responsive” to, or “directly on,” another element, there are no intervening elements present. As used herein the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0113] Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper.” and the like, may be used herein for ease of description to describe one element or feature in relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 130 degrees or at other orientations) and the spatially relative descriptors used herein may be interpreted accordingly.

[0114] Unless otherwise defined, the terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which these concepts belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and / or the present specification and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0115] Further to the descriptions above, a user may be provided with controls allowing the user to make an election as to both if and when systems, programs, or features described herein may enable collection of user information (e.g., information about a user's social network, social actions, or activities, profession, a user's preferences, or a user's current location), and if the user is sent content or communications from a server. In addition, certain data may be treated in one or more ways before it is stored or used, so that personally identifiable information is removed. For example, a user's identity may be treated so that no personally identifiable information can be determined for the user, or a user's geographic location may be generalized, or location information may be obtained (such as to a city, zip code, or state level), so that a particular location of a user cannot be determined. Thus, the user may have control over what information is collected about the user, how that information is used, and what information is provided to the user.

[0116] While certain features of the described implementations have been illustrated as described herein, many modifications, substitutions, changes, and equivalents may occur to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover such modifications and changes as fall within the scope of the implementations. It will be understood that they have been presented by way of example only, not limitation, and various changes in form and details may be made. Any portion of the apparatus and / or methods described herein may be combined in any combination, except mutually exclusive combinations. The implementations described herein can include various combinations and / or sub-combinations of the functions, components, and / or features of the different implementations described. As such, the scope of the present disclosure is not limited to the particular combinations hereafter claimed, but instead extends to encompass any combination of features or example implementations described herein irrespective of whether or not that particular combination has been specifically enumerated in the accompanying claims at this time.

Claims

WHAT IS CLAIMED IS:

1. A method comprising: positioning a laser to operate from a growth side of a semiconductor article that includes a starting substrate, a growth substrate layer deposited on the starting substrate, and an epitaxial layer deposited on the growth substrate layer, the growth side corresponding to the epitaxial layer and being opposite the starting substrate; configuring the laser to emit light to a focal point within the grow th substrate layer, the light having a photon energy less than a bandgap associated with the epitaxial layer; and operating the laser to generate a defect at the focal point within the growth substrate layer, the defect included in a pattern of defects induced by the laser.

2. The method of claim 1, wherein the semiconductor article is a growth w afer configured for epitaxial fabrication of microLED components.

3. The method of claim 2. wherein the growth wafer includes an array of microLED components including: red components formed within the epitaxial layer and associated with a first bandgap; green components formed within the epitaxial layer and associated with a second bandgap; and blue components formed within the epitaxial layer and associated with a third bandgap; wherein the photon energy is less than each of the first bandgap, the second bandgap. and the third bandgap.

4. The method of any of claims 1 to 3, further comprising: aligning, subsequent to generating the pattern of defects, the semiconductor article with an additional semiconductor article, the growth side of the semiconductor article facing the additional semiconductor article; positioning an additional laser to operate from a substrate side of the semiconductor article opposite the growth side; and producing a layer transfer for a portion of the semiconductor article by: operating the additional laser to expand the defect to detach, from the portion of the semiconductor article, the epitaxial layer and part of the growth substrate layer, andattaching, to the additional semiconductor article, the epitaxial layer and the part of the growth substrate layer detached from the portion of the semiconductor article.

5. The method of claim 4, wherein the additional laser is configured to emit light having an additional photon energy, the additional photon energy being different from the photon energy of the light emitted by the laser and being less than a bandgap associated with the starting substrate.

6. The method of any of claims 4 to 5, wherein the additional semiconductor article is a microLED backplane wafer including circuitry configured to drive microLED components.

7. The method of any of claims 4 to 6, wherein: the portion of the semiconductor article includes a plurality of microLED components fabricated on the semiconductor article at a particular pitch; the operating the additional laser to expand the defect causes a crack to connect the defect to additional defects of the pattern of defects within the portion of the semiconductor article; and the particular pitch is equal to a final pitch used for the plurality of microLED components when attached to the additional semiconductor article.

8. The method of any of claims 4 to 6, wherein: the portion of the semiconductor article includes an individual microLED component fabricated on the semiconductor article at a particular pitch; the operating the additional laser to expand the defect causes a crack to connect the defect to additional defects of the pattern of defects within the portion of the semiconductor article; and the particular pitch is smaller than a final pitch used for the individual microLED component when attached to the additional semiconductor article.

9. The method of any of claims 1 to 8, wherein: the starting substrate is constructed of silicon (Si); the growth substrate layer is constructed of gallium nitride (GaN); and the epitaxial layer is constructed of indium gallium nitride (InGaN).

10. The method of any of claims 1 to 9, wherein the semiconductor article further includes an additional metal layer deposited on the epitaxial layer.

11. The method of any of claims 1 to 10, wherein the pattern of defects is configured so that sufficient growth substrate material remains between defects of the pattern of defects to prevent detachment of the epitaxial layer from the starting substrate during processing of the semiconductor article and prior to a layer transfer being produced.

12. A semiconductor article comprising: a starting substrate: a growth substrate layer deposited on the starting substrate; an epitaxial layer deposited on the grow th substrate layer; and a pattern of defects generated within the grow th substrate layer, the pattern of defects induced by a laser operating from a growth side of the semiconductor article that corresponds to the epitaxial layer and is opposite the starting substrate; wherein the laser is configured to emit light w ith a photon energy less than a bandgap associated with the epitaxial layer, the light being focused to a focal point within the grow th substrate layer.

13. The semiconductor article of claim 12, w h erein the semiconductor article is implemented as a grow th w afer configured for epitaxial fabrication of microLED components.

14. The semiconductor article of claim 13, w herein the growth wafer includes an array of microLED components including: red components formed within the epitaxial layer and associated with a first bandgap; green components formed within the epitaxial layer and associated with a second bandgap; and blue components formed within the epitaxial layer and associated with a third bandgap; wherein the photon energy is less than each of the first bandgap, the second bandgap. and the third bandgap.

15. The semiconductor article of any of claims 12 to 14, wherein: the starting substrate is constructed of silicon (Si); the growth substrate layer is constructed of gallium nitride (GaN); and the epitaxial layer is constructed of indium gallium nitride (InGaN).

16. The semiconductor article of any of claims 12 to 15. wherein the pattern of defects is configured so that sufficient growth substrate material remains between defects of the pattern of defects to prevent detachment of the epitaxial layer from the starting substrate during processing of the semiconductor article and prior to a layer transfer being produced.

17. A system comprising: a laser configured to emit light having a photon energy less than a bandgap associated with an epitaxial layer of a semiconductor article that includes a starting substrate, a growth substrate layer deposited on the starting substrate, and the epitaxial layer deposited on the growth substrate layer; and one or more processors communicatively coupled to a memory and configured to execute instructions stored within the memory to perform a process comprising: positioning the laser to operate from a grow th side of the semiconductor article, the growth side corresponding to the epitaxial layer and being opposite the starting substrate; configuring the laser to emit the light to a focal point within the growth substrate layer; and operating the laser to generate a defect at the focal point within the growth substrate layer, the defect included in a pattern of defects induced by the laser.

18. The system of claim 17, further comprising an additional laser and wherein the process further comprises: aligning, subsequent to generating the pattern of defects, the semiconductor article with an additional semiconductor article, the growth side of the semiconductor article facing the additional semiconductor article; positioning the additional laser to operate from a substrate side of the semiconductor article opposite the growth side; and producing a layer transfer for a portion of the semiconductor article by:operating the additional laser to expand the defect to detach, from the portion of the semiconductor article, the epitaxial layer and part of the growth substrate layer, and attaching, to the additional semiconductor article, the epitaxial layer and the part of the growth substrate layer detached from the portion of the semiconductor article.

19. The system of claim 18, wherein: the additional laser is configured to emit light having an additional photon energy, the additional photon energy being different from the photon energy of the light emitted by the laser and being less than a bandgap associated with the starting substrate; the semiconductor article is a grow th wafer configured for epitaxial fabrication of an array of microLED components; and the additional semiconductor article is a microLED backplane wafer including circuitry configured to drive the array of microLED components.

20. The system of claim 19, wherein: the portion of the semiconductor article includes an individual microLED component fabricated on the semiconductor article at a particular pitch; the operating the additional laser to expand the defect causes a crack to connect the defect to additional defects of the pattern of defects within the portion of the semiconductor article; and the particular pitch is smaller than a final pitch used for the individual microLED component when attached to the additional semiconductor article.

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