BACKGROUND

Field

[0001] Implementations of the present disclosure relate to apparatus, systems, and methods of using a retaining device, for example in relation to light-emitting diode (LED) laser lift-off (LLO). In one aspect, a retaining device (e.g., docking device) may including a sealing ring and a compliant layer on a base plate, the compliant layer forming an area to securely retain a substrate with LEDs during LLO operations.

Description of the Related Art

[0002] Optical devices such as light-emitting diodes (LEDs) may be initially formed as a thin layer on a substrate (growth substrate), for example sapphire. The growth substrate with thin layer may be adhered to an interposer. Laser liftoff (LLO) is a process that can be used to separate the thin layers from the growth substrate, leaving the thin layer on another surface, such as the interposer (e.g., a polymer firm, stamp, or adhesive film). LLO may use a homogenized ultraviolet (UV) wavelength laser beam having a working wavelength (e.g., deep UV, such as a 248 nm wavelength laser). Typically, for LLO, the substrate is transparent to the working wavelength, and the target layer (e.g., gallium nitride (GaN)) is opaque to the working wavelength. During processing of the sample, the laser beam is directed towards the target layer, passing through the transparent support (e.g. sapphire, glass). Energy of the laser beam is absorbed in the opaque layer, creating a plasma at the interface, vaporizing the target layer at the interface, allow for clean debonding of the thin layer of devices from the grown substrate. The transparent substrate serves as a carrier, allowing easy and safe manipulation of the relatively fragile target layer to fabricate thin and complex structures, such as those used in LED displays (e.g., ultra LED displays).

[0003] However, the process of vaporing the target layer during LLO may cause undesirable shift, fly away, or other displacement of the thin layer and its optical devices. For example, vaporizing GaN during LLO generates nitrogen gas that could displace the detached optical devices by overcoming the adhesive force with the underlying interposer. Among other issues, such as potential damage to the fragile and brittle optical devices, displacement can impact the subsequent alignment of the optical devices to the backplanes of active displays. As such, during LLO, it is desirable to securely retain (e.g., dock, hold, grip, secure) the optical devices to reduce or eliminate potential displacement and damage. Accordingly, what is needed in the art are devices, systems, and methods for retaining a substrate, such as in relation to retaining optical devices in relation to LED LLO.

SUMMARY

[0004] Implementations of the present disclosure relate to apparatus, systems, and methods of using a retaining device, for example in relation to light-emitting diode (LED) laser lift-off (LLO). In one or more implementations, a retaining device includes a base plate; a sealing ring disposed on the base plate and defining a sealed area within the sealing ring, the sealing ring having a first surface on the base plate and second surface operable to contact a chuck to provide a holding force for a substrate to be retained; and a compliant layer disposed on the base plate within the sealed area, forming an area operable to receive the substrate that is adhered to an interposer disposed on the chuck, and operable to contact the interposer.

[0005] In one or more implementations, a system for LLO includes a chuck to retain a substrate that is adhered to an interposer, a retaining device comprising a base plate, a sealing ring, and a compliant layer, the sealing ring disposed on the base plate and defining a sealed area within the sealing ring, the sealing ring having a first surface on the base plate and second surface operable to contact the chuck to provide a holding force for the substrate, and the compliant layer disposed on the base plate within the sealed area, forming an area operable to receive the substrate, and operable to contact the interposer, and a laser light source configured to apply laser light to the substrate through the base plate to lift off one or more optical devices formed on the substrate.

[0006] In one or more implementations, a method for retaining a substrate includes disposing a work piece on a chuck, the work piece comprising the substrate adhered to an interposer, applying a retaining device to the work piece and chuck, the retaining device comprising a base plate, a sealing ring defining a sealed area and contacting the chuck, and a compliant layer within the sealed area, contacting the interposer, and the compliant layer forming an area operable to receive the substrate, and providing a holding force between the work piece and the retaining device to retain the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] So that the manner in which the above-recited features of the disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to implementations, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only common implementations of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective implementations.

[0008] Figure 1A is a schematic, cross-sectional view of a device according to one or more implementations.

[0009] Figure 1 B is a schematic, cross-sectional view of a device according to one or more implementations.

[0010] Figure 2A is a schematic, perspective view of a retaining device according to one or more implementations.

[0011] Figure 2B is a schematic, perspective view of a retaining device according to one or more implementations. [0012] Figure 3 is a schematic, cross-sectional view of a retaining device according to one or more implementations.

[0013] Figure 4 is a schematic, perspective view of a retaining device according to one or more implementations.

[0014] Figure 5 is a flow diagram of a method for retaining a substrate according to one or more implementations.

[0015] Figure 6A is a schematic, cross-sectional view of a device according to one or more implementations.

[0016] Figure 6B is a schematic, cross-sectional view of a device according to one or more implementations.

[0017] Figure 7A is a schematic, perspective view of a retaining device according to one or more implementations.

[0018] Figure 7B is a schematic, perspective view of a retaining device according to one or more implementations.

[0019] Figure 8 is a flow diagram of a method for retaining a substrate according to one or more implementations. To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one or more implementations may be beneficially utilized on other implementations without specific recitation.

DETAILED DESCRIPTION

[0020] Implementations of the present disclosure relate to apparatus, systems, and methods of using a retaining device, for example in relation to light-emitting diode (LED) laser lift-off (LLO). In one implementation, a retaining device may including a sealing ring and a compliant layer on a base plate, the compliant layer forming an area to securely retain a substrate with LEDs during LLO operations. [0021] In one or more implementations, a device includes a base plate; a sealing ring, and a compliant layer. The sealing ring is disposed on the base plate, defining a sealed area within the sealing ring. The sealing ring has a first surface on the base plate and second surface. The second surface is operable to contact a chuck to provide a holding force for a substrate to be retained. The compliant layer is disposed on the base plate within the sealed area. The compliant layer forms an area operable to receive the substrate that is adhered to an interposer disposed on the chuck, and operable to contact the interposer.

[0022] Another implementation includes a system for LLO. The system includes a chuck to retain a substrate that is adhered to an interposer. The system also includes a retaining device that includes a base plate, a sealing ring, and a compliant layer. The sealing ring is disposed on the base plate and defines a sealed area within the sealing ring. The sealing ring also has a first surface on the base plate and second surface operable to contact the chuck to provide a holding force for the substrate. The compliant layer is disposed on the base plate within the sealed area, forming an area operable to receive the substrate, and operable to contact the interposer. The system also includes a laser light source configured to apply laser light to the substrate through the base plate to lift off one or more optical devices formed on the substrate.

[0023] Figure 1A is a schematic, cross-sectional view of a device 101 according to one or more implementations. The device 101 includes both a retaining device 110 and a substrate assembly 120. The retaining device 110 includes a base plate 112, sealing ring 114, and compliant layer 116. The substrate assembly 120 includes interposer substrate 128, interposer 126, and substrate 122. A chuck 130, together with retaining device 110, may secure the substrate assembly 120. Optical devices 124 may be formed on the substrate 122.

[0024] The base plate 112 may be of a material that is transparent or substantially transparent to laser light, such as for frequencies of light used by a laser during LLO operations. In one or more implementations, the base plate 112 may be of a uniform thickness, for example at least over portions of base plate 112 that will be over substrate 122. The base plate may include one or more steps or other features configured to support or otherwise provide a mating surface for the sealing ring 114. In one or more implementations, the base plate 112 may be a quartz plate, and be about 0.5 mm to 1 mm in thickness.

[0025] The compliant layer 116 may be formed on the base plate 112. The compliant layer 116 may be a patterned layer with an area (e.g., opening, slot, substrate area, window) sized or otherwise operable to receive a substrate 122. The compliant layer 116 may be a type of polymer, for example polydimethylsiloxane (PDMS) (which may also be referred to as dimethicone), a rubber, a perforated film, or a polyurethane (Pll). In one or more implementations, the compliant layer 116 may be separated into multiple (two or more) portions. Compliant layer 116 may be lithographically-patterned or formed on base plate 112. Separation between the portions of the compliant layer 116 may form one or more air channels that allow for the passage of gases, for example when a suction (vacuum) source is applied. The opening in compliant layer 116 that is sized to receive the substrate 122 may also be sized or otherwise operable to provide air channels around the edges of substrate 122 to allow for the passage of gases away from substrate 122, including when the laser light is applied during LLO. In one or more implementations, the compliant layer 116 may be of a substantially same thickness as substrate 122. In one or more implementations, the compliant layer 116 is between 100 percent and 101 percent a thickness of a stack height that includes the substrate 122.

[0026] In one or more implementations the compliant layer 116 may be of a relatively rigid material (e.g., relatively more rigid than the compliant layer formed of the type of polymer described above where the compliant layer 116 is between 100 percent and 101 percent a thickness of the stack height). In one or more implementations, the compliant layer 116 is between 99 percent and 100 percent a thickness of the stack height that includes the substrate 122.

[0027] The sealing ring 114 may be disposed or otherwise affixed to base plate 112. In one or more implementations, sealing ring 114 may bound (define, enclose) a sealing area that includes the compliant layer 116. The sealing ring 114 may an O-ring, though other sealing profiles and cross sections may be used consistent with the description herein. For example, the sealing ring 114 may have an x profile, square or rectangular profile, u profile, or triangular or knife profile. In one or more implementations, the sealing ring 114 may be a perfluoroelastomer (e.g., Kalrez®) or Polytetrafluoroethylene (PTFE) (e.g., Teflon®). In one or more implementations, the sealing ring 114 may be affixed to the base plate 112 using glue or other adhesive.

[0028] The substrate 122 may be, in one or more implementations, a semiconductor wafer or chip on which optical devices 124 may be formed. For example, the substrate 122 may be a sapphire substrate on which are formed LED devices. The optical devices may have a layer (target layer, opaque layer) at the interface between the substrate 122 and the optical devices 124 that is to be vaporized or others acted on to debond the optical devices 124 from the substrate 122 during the LLO process. In one or more implementations, the layer may be gallium nitride (GaN). The substrate 122 may be applied (physically adhered) to an interposer 126 that is in turn applied to (physically adhered to) an interposer substrate 128. A holding force may be applied to interposer substrate 128 to hold the interposer substrate 128 to a chuck 130. In one or more implementations, the holding force is a suction force (vacuum force) and the chuck 130 is a vacuum chuck in communication with a suction source (vacuum source). The interposer 126 and interposer substrate 128 may be an adhesive film on glass. One or both of the interposer 126 or the interposer substrate 128 may be or include a polymer film, stamp, or adhesive film.

[0029] Figure 1 B is a schematic, cross-sectional view of a device 102 according to one or more implementations. Similar to device 101 , the device 102 includes both a retaining device 110 and a substrate assembly 120. Device 102 shows the retaining device 110 applied to the substrate assembly 120.

[0030] Upon application of retaining device 110 to substrate assembly 120, sealing ring 114, which is at least partially compressible, may contact the chuck 130 and provide a seal. Where chuck 130 is a vacuum chuck and a suction is applied via the vacuum chuck, volume 140 is a low pressure volume, providing a holding force that holds (e.g., retains, fixes) the retaining device 110 to substrate assembly 120 and reducing or eliminating movement of substrate 122 relative to interposer 126 during application of laser light 150 during the LLO procedure to lift the optical devices 124 from substrate 122 and transfer (bond, adhere) the optical devices 124 to the interposer 126. Volume 140 includes volumes between the sealing ring 114, base plate 112, and substrate assembly 120, as well as volumes within the area operable to receive the substrate 122 generally within the compliant layer 116.

[0031] Upon application of retaining device 110 to substrate assembly 120, the compliant layer 116 may contact the interposer 126 to which the substrate 122 (and the optical devices 124) are adhered. The compliant layer 116 provides a surface against which the interposer 126 may provide a force (e.g., pressure) when the holding force is applied from the base plate 112 that is substantially even (which may be referred to as uniform, level, and/or continuous) with the pressure applied between the base plate 112 and the substrate 122 and the pressure applied between the substrate 122 and the interposer 126. This even pressure on the substrate 122 and the interposer 126 may reduce or eliminate undesirable shift of the substrate 122 relative to the interposer 126 (e.g., die shift) that can impact subsequent alignment of the optical devices in subsequent steps of processing (e.g., fabrication), for examples alignment of LEDs to an active display backplane.

[0032] In one or more implementations where the compliant layer 116 is of a relatively rigid material, the base plate 112 may be held against substrate 122 when the holding force is applied (e.g., from a suction or vacuum source), and at least a portion of the relatively rigid material of the compliant layer 116 may also contact the base plate 112. In one or more implementations, such contact may aid in securing the substrate 122 relative to the interposer 126 to reduce or eliminate undesirable shift of the substrate 122 relative to the interposer 126, for example during a LLO operation to transfer optical devices 124. In one or more implementations, laser light 150 may be UV laser light from a UV laser source (e.g., deep UV laser source of 248 nm wavelength), though other laser source types and wavelengths (or frequencies) may be used consistent with the techniques described herein.

[0033] Figure 2A is a schematic, perspective view of a retaining device 201 according to one or more implementations. The retaining device 201 may be an example of retaining device 110 and at least portions of substrate assembly 120. The retaining device 201 includes base plate 112, sealing ring 114, and compliant layer 116, and is shown retaining (holding, securing, affixing) a substrate 205 and device glass 210. Substrate 205 and device glass 210 may be examples of at least portions of substrate assembly 120. In one example, substrate 205 includes substrate 122 and optical devices 124, and device glass 210 may be or include the interposer substrate 128 and interposer 126 onto which the optical devices 124 are to be transferred via the LLO.

[0034] As shown for retaining device 201 , compliant layer 116 includes four portions, with an opening (slot, area, substrate area) operable to provide space for the substrate 205 to be retained (secured, held). Compliant layer 116 is formed to provide one or more volumes 140 (e.g., channels) that provide a path for gases to exit (or enter) the sealing area within the sealing ring 114 that is formed by the application of a suction (vacuum) source to the retaining device 201 , for example by the use of a vacuum chuck, such as chuck 130. Although compliant layer 116 is shown having four portions, a greater or fewer number of portions may be used, such as two, three, five, six, or eight. A greater number of portions may be used to provide a greater number of channels to allow a greater rate of gas exit (or entry) into the area around substrate 205. A greater number of portions for a same diameter (or other overall dimensions) of the compliant layer 116 will reduce the total area of the compliant layer 116, which may result in a less even application of pressure to the compliant layer 116 and substrate 205. A fewer number of portions may be used to provide a fewer number of channels for a slower rate of gas exit (or entry) into the area around substrate 205. A fewer number of portions for a same diameter (or other overall dimensions) of the compliant layer 116 will increase the total area of the compliant layer 116, which may result in a more even application of pressure to the compliant layer 116 and substrate 205.

[0035] Figure 2B is a schematic, perspective view of a retaining device 202 according to one or more implementations. The retaining device 202 is an example of an exploded view of retaining device 201 .

[0036] Figure 3 is a schematic, cross-sectional view of a retaining device assembly 300 according to one or more implementations, according to one or more implementations. Retaining device assembly 300 includes a base plate 112, sealing ring 114, and compliant layer 116. In one or more implementations, sealing ring 114 may be secured to base plate 112 with an adhesive 310 (e.g., glue). Retaining device assembly 300 can interface with a substrate 122 and device glass 210 (including interposer 126 and interposer substrate 128), for example during a LLO procedure. A total stack height for the retaining device assembly 300 under compression is height 308.

[0037] In one or more implementations, sealing ring 114 of retaining device assembly 300 may have a height 304 in the z-axis away from the base plate 112. Height 304 is greater than height 306, which is the height from the base of the sealing ring 114 to the top of the device glass 210 (and the interface with a chuck 130), including a height 314 of a step 312 of base plate 112 together with a height of the compliant layer 116 and device glass 210. The resulting height difference 302 allows for compression of sealing ring 114 when retaining device assembly 300 is pressed against a chuck 130 (not shown) (e.g., a vacuum chuck). In one or more implementation, when a section (vacuum) source is applied, a hold force may be applied, retaining (securing, holding) substrate 205 such that the LLO procedure may be conducted without movement of substrate 205 relative to device glass 210.

[0038] Figure 4 is a schematic, perspective view of a retaining device 400 according to one or more implementations. The retaining device 400 may be an example of retaining device 110 and at least portions of substrate assembly 120. The retaining device 400 includes base plate 112, sealing ring 114, and compliant layer 415, and is shown retaining (holding, securing, affixing) six substrates 420 and device glass 210. Substrates 420 and device glass 210 may be examples of at least portions of substrate assembly 120. Each substrate of substrates 420 may be an example of a substrate 205. In one example, each substrate of substrates 420 includes a substrate 122 and optical devices 124, and device glass 210 may be or include the interposer substrate 128 and interposer 126 onto which the optical devices 124 are to be transferred via the LLO from respective substrates of substrates 420.

[0039] As shown for retaining device 400, compliant layer 415 includes three portions, with areas (e.g., openings, slots, substrate areas, windows) operable to provide space for the substrates 420 to be retained (e.g., secured, held). Although shown with two areas in compliant layer 415, each area retaining three substrates of substrates 420, different configurations may be used consistent with the present disclosure.

[0040] Compliant layer 116 is formed to provide one or more volumes 140 (e.g., channels) that provide a path for gases to exit (or enter) the sealing area within the sealing ring 114 that is formed by the application of a suction (e.g., vacuum) source to the retaining device 400, for example by the use of a vacuum chuck, such as chuck 130. Although compliant layer 415 is shown having three portions, a greater or fewer number of portions may be used, such as two, four, five, six, or eight. In one or more implementations, a greater number of portions may be used to provide a greater number of channels to allow a greater rate of gas exit (or entry) into the area around substrates 420. A greater number of portions for a same diameter (or other overall dimensions) of the compliant layer 116 will reduce the total area of the compliant layer 116, which may result in a less even application of pressure to the compliant layer 116 and substrate 205. In one or more implementations, a fewer number of portions may be used to provide a fewer number of channels for a slower rate of gas exit (or entry) into the area around substrate 205. A fewer number of portions for a same diameter (or other overall dimensions) of the compliant layer 116 will increase the total area of the compliant layer 116, which may result in a more even application of pressure to the compliant layer 116 and substrate 205.

[0041] Figure 5 is a flow diagram of a method 500 of retaining a substrate.

[0042] Operation 505 of the method 500 includes disposing a substrate on a chuck. The substrate is adhered to an interposer. In one or more implementations, the substrate may be an example of substrate 122, substrate 205, and/or substrate 420, and the chuck may be an example of chuck 130. In one or more implementations, the interposer may be an example of interposer 126, and the interposer can include one or more different components or layers, such as an interposer substrate 128, between the substrate and the chuck.

[0043] Operation 510 of the method 500 includes applying a retaining device to the substrate and chuck. The retaining device is a base plate, a sealing ring defining a sealed area, and a compliant layer within the sealed area. The sealing ring defines a sealed area and is operable to contact the chuck. The compliant layer is operable to contact the interposer and form an area to receive the substrate. In one or more implementations, the retaining device may be an example of at least portions of retaining device 110, retaining device 201 , retaining device 202 retaining device assembly 300, and/or retaining device 400.

[0044] Operation 515 of the method 500 includes providing a holding force between the substrate and retaining device to retain the substrate.

[0045] Figure 6A is a schematic, cross-sectional view of a device 601 according to one or more implementations. The device 601 includes both a retaining device 610 and a substrate assembly 120. The retaining device 110 includes a base plate 112 and sealing ring 114. The substrate assembly 120 includes interposer substrate 128, interposer 126, and substrate 122, and may be an example of substrate assembly 120 described herein.

[0046] The base plate 112 and the sealing ring 114 may be examples of base plate 112 and the sealing ring described herein, for example with reference to retaining device 110. Different from retaining device 110, in one or more implementations, retaining device 610 omits the compliant layer. The base plate 112 is held against substrate 122 when the holding force is applied (e.g., from a suction or vacuum source). Such contact may aid in securing the substrate 122 relative to the interposer 126 to reduce or eliminate undesirable shift of the substrate 122 relative to the interposer 126, for example during a LLO operation to transfer optical devices 124.

[0047] Figure 6B is a schematic, cross-sectional view of a device 602 according to one or more implementations. Similar to device 601 , the device 602 includes both a retaining device 610 and a substrate assembly 120. Device 602 shows the retaining device 610 applied to the substrate assembly 120 in the one or more implementations where the compliant layer is omitted.

[0048] Figure 7A is a schematic, perspective view of a retaining device 701 according to one or more implementations where a compliant layer is omitted. The retaining device 701 may be an example of retaining device 610 and at least portions of substrate assembly 120. The retaining device 601 includes base plate 112 and sealing ring 114, and is shown retaining a substrate 205 and device glass 210. Substrate 205 and device glass 210 may be examples of at least portions of substrate assembly 120. In one example, substrate 205 includes substrate 122 and optical devices 124, and device glass 210 may be or include the interposer substrate 128 and interposer 126 onto which the optical devices 124 are to be transferred via the LLO.

[0049] Figure 7B is a schematic, perspective view of a retaining device 702 according to one or more implementations. The retaining device 702 is an example of an exploded view of retaining device 701 .

[0050] Figure 8 is a flow diagram of a method 800 of retaining a substrate.

[0051] Operation 805 of the method 800 includes disposing a substrate on a chuck. The substrate is adhered to an interposer. In one or more implementations, the substrate may be an example of substrate 122, substrate 205, and/or substrate 420, and the chuck may be an example of chuck 130. In one or more implementations, the interposer may be an example of interposer 126, and the interposer can include one or more different components or layers, such as an interposer substrate 128, between the substrate and the chuck.

[0052] Operation 810 of the method 800 includes applying a retaining device to the substrate and chuck. The retaining device is a base plate and a sealing ring. The sealing ring defines a sealed area and is operable to contact the chuck. The sealing ring is further operable to support the base plate at a distance from a plane of the substrate in the absence of a holding force (e.g., a vacuum or suction source) provided between the substrate and the retaining device. In one or more implementations, the retaining device may be an example of at least portions of retaining device 610, retaining device 601 , retaining device 602 retaining device 701 , and/or retaining device 702.

[0053] Operation 815 of the method 800 includes providing the holding force between the substrate and retaining device to cause the base plate to contact the substrate and retain the substrate.

[0054] Benefits of the present disclosure include increased alignment and stability of optical devices (e.g., LEDs), for example during LLO, improved yield of optical devices to the interposer, reduced defects, reduced waste, reduced processing times, increased throughput, and/or reduced or eliminated errors and/or failures of LLO operations.

[0055] It is contemplated that various subject matter disclosed herein may be combined. As an example, one or more aspects, features, components, and/or properties of the device 101 , device 102, retaining device 201 , retaining device 202, retaining device assembly 300, retaining device 400, and/or method 500 may be combined. Moreover, it is contemplated that various subject matter disclosed herein may include some or all of the aforementioned benefits.

[0056] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The present disclosure also contemplates that one or more aspects of the embodiments described herein may be substituted in for one or more of the other aspects described. The scope of the disclosure is determined by the claims that follow.