• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    A light emitting device die having a mesa configuration on the substrate and an electrode on the mesa phase is flip-chip configuration on the submount by forming a conductive die attach material of a predetermined pattern on at least one of the electrode and the submount and mounting the light emitting device die to the submount Is attached. The predetermined pattern of conductive die attach material is selected to prevent the conductive die attach material from contacting regions with opposite conductivity types when the light emitting element die is mounted to the submount. The conductive die attach material of the desired pattern can provide a volume of die attach material that is less than the volume defined by the distance between the electrode and the submount and the area of the electrode. A light emitting element die having a conductive die attach material of a predetermined pattern is also provided. A light emitting device having a gallium nitride-based light emitting region on a substrate such as a silicon carbide substrate has a flip-chip configuration by attaching an electrode of the gallium nitride-based light emitting region to a submount using a B-stage curable die epoxy. It may be mounted. Also provided is a light emitting device die having a B-stage curable die epoxy.
    公开号:KR20040029381A
    申请号:KR10-2004-7001063
    申请日:2002-07-22
    公开日:2004-04-06
    发明作者:데이비드 슬레이터；자예쉬 바라단；존 에드몬드；마크 라페토；앤워 모하메드；게리 네글레이；피터 앤드류스
    申请人:크리 인코포레이티드；크리 마이크로웨이브 인크.；
    IPC主号:
    专利说明:

    Flip chip bonding of light emitting devices and light emitting devices suitable for flip-chip bonding}
    [3] GaN based light emitting diodes (LEDs) typically have an insulating, semiconductor or conductor substrate, such as sapphire or SiC, on which a plurality of GaN based epitaxial layers are deposited. The epitaxial layers have an active region with a p-n junction that emits light when electricity is applied. A typical LED is mounted onto a submount with the substrate side down, which is referred to as a package or lead frame (hereinafter referred to as "submount"). 1 schematically shows a conventional LED, which is an n-type SiC substrate 10, a p-GaN base layer 16 grown on the substrate and patterned with mesas and an n-GaN base. It has an active region 12 having a layer 14 of. Metal p-electrode 18 is deposited on and electrically coupled to p-GaN layer 16 and wire bond connections 28 are made of bond pads 20 on p-electrode 18. The n-electrode 22 electrically connected thereto on the conductive substrate is attached to the metallic submount 24 using the conductive epoxy 26. In a conventional procedure, conductive epoxy 26 (typically silver epoxy) is deposited on the submount and the LED is pressed into the epoxy 26. The epoxy is then thermally cured and hardened, providing an electrically conductive and stable mounting for the LED chip. Light generated in the active region 12 is oriented above and outside the device. However, a substantial amount of light generated can be transferred into the substrate and partially absorbed by the epoxy 26.
    [4] Flip chip mounting of the LEDs includes mounting the LED to the submount with the substrate side up. Light is then extracted and irradiated through the transparent substrate. Flip chip mounting may be a particularly desirable technique for mounting LEDs, in particular SiC based. Since SiC has a higher refractive index than GaN, the light generated in the active region does not reflect internally at the GaN / SiC interface (ie, it is not reflected back into the GaN base layer). Flipchip mounting of SiC based LEDs can provide improved light extraction when employing certain chip shaping techniques known in the art. Flipchip packaging of LEDs of SiC may have other advantages, such as improved heat extraction / dissipation, which may be desirable depending on the particular application to the chip.
    [5] The problem of flip chip mounting is as shown in FIG. That is, when the chip is mounted in a flip chip manner on a conductive submount or package, conventional techniques may not be possible. Typically, conductive die attach material 26, such as silver epoxy, is deposited on the chip and / or submount 24, and the chip is pressed onto the submount 24. This causes the viscous conductive die attach material 26 to be squeezed out to contact the n-type layers 14, 10 in the device, thereby shunting the pn junction in the active region with predictably undesirable results. To form a Schottky diode connection. Therefore, new technology for flip chip mounting of LEDs may be needed.
    [1] The present invention claims the priority of US Provisional Application No. 60 / 307,311, "Flip Chip Bonding of Light Emitting Diodes," filed July 23, 2001, the disclosure of which is incorporated herein.
    [2] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly, to a semiconductor device mounted on a submount in a flip-chip configuration.
    [23] 1 is a schematic diagram of a conventional LED.
    [24] 2 is a schematic diagram of a flip-chip mounted LED using conventional techniques.
    [25] 3A, 3B, 3C, and 3D illustrate patterns of die attach material in accordance with various embodiments of the present invention.
    [26] 4 is a flow chart illustrating operation in accordance with embodiments of the present invention.
    [27] 5 illustrates an LED attached to a submount in accordance with embodiments of the present invention.
    [28] 6 is a plan view of an LED with a p-type electrode having a pump of die attach material in a pattern according to embodiments of the invention.
    [29] FIG. 7 is a side view of the LED of FIG. 6. FIG.
    [30] 8 is a side view of the LED of FIGS. 6 and 7 after being mounted to the submount.
    [6] Embodiments of the present invention provide a light emitting device having a gallium nitride based light emitting region by mounting an electrode of a gallium nitride based light emitting region to a submount using a B-stage curable die epoxy. It provides mounting in a flip-chip configuration on a silicon carbide substrate.
    [7] In a particular embodiment of the invention, the electrode is mounted to a submount by forming a pattern of B-stage curable die epoxy on the electrode, the pattern covering only a portion of the electrode. Electrodes in the light emitting region of the gallium nitride base are attached to the submount using a predetermined pattern of B-stage curable die epoxy. Certain patterns of B-stage curable die epoxy may be provided by applying B-stage curable die epoxy to the electrodes by screen printing. Preferably, screen printing provides an application resolution of about 4 mils of B-stage curable die epoxy.
    [8] Certain patterns of B stage curable die epoxy may be provided by dispensing the B-stage epoxy to the desired locations of the electrode. Moreover, a predetermined pattern of B-stage curable die epoxy may be provided by coating the electrode with B stage epoxy and optionally removing the B-stage epoxy from the electrode to provide the desired pattern. The B-stage epoxy may optionally be provided by laser scribing the B-stage epoxy to provide the epoxy selectively to provide the desired pattern. If the B-stage epoxy is a photosensitive B-stage epoxy, the B-stage epoxy may be selectively removed using photolithography to provide the desired pattern. The predetermined pattern of B-stage curable die epoxy may be provided by pin transferring the B-stage epoxy to a location on the electrode to provide the desired pattern.
    [9] In another embodiment of the present invention, forming the desired pattern of B-stage curable die epoxy follows pre-curing the B-stage epoxy. Precure of the B-stage epoxy may be provided by precuring the B-stage epoxy using a temperature of about 50 to about 150 ° C. In particular, the B-stage epoxy may be pre-cured using a temperature of about 85 ° C. Moreover, the electrode of the light emitting region of the gallium-nitride base uses a predetermined pattern of B-stage curable die epoxy to place the light emitting element in the submount and B- to allow the B-stage epoxy to reflow. The stage epoxy can be attached to the submount by heating to the final curing temperature. The B-stage epoxy may be heated to a temperature of at least about 150 ° C.
    [10] In certain embodiments, the predetermined pattern is a single nodule of B-stage epoxy on an electrode. The predetermined pattern may also be a plurality of bumps of B-stage epoxy on the electrode. The predetermined pattern may also be multiple lines of B-stage epoxy on the electrode. The predetermined pattern may also be a criss-cross pattern of B-stage epoxy on the electrode.
    [11] In another embodiment of the present invention, a light emitting device having a mesa configuration on a substrate and an electrode on the mesa forms a conductive die attach material of a predetermined pattern on at least one of the submount and the electrode and submounts the light emitting device die. By attaching to it, it is attached to the submount in the configuration of a flip chip. The conductive die attach material of a predetermined pattern is selected to prevent the conductive die attach material from contacting the sidewalls of the mesa or the substrate when the light emitting element die is mounted to the submount. The conductive die attach material of the desired pattern can provide a volume of die attach material that is less than the volume defined by the distance between the electrode and the submount and the area of the electrode.
    [12] In another embodiment of the invention, the predetermined pattern is a single nodule's conductive die attach material on the electrode. The predetermined pattern may be a plurality of bumps of conductive die attach material on the electrode. The predetermined pattern may be a plurality of lines of conductive die attach material on the electrode. The predetermined pattern may be a crisscross pattern of die attach material on the electrode.
    [13] In another embodiment of the invention, the conductive die attach material is at least one of a B-stage curable die epoxy, a solder paste, a pattern of a solder pump, and / or conductive polymers. If the conductive die attach material is a solder paste, the predetermined pattern may be provided by forming the solder paste of the desired pattern by at least one of screen printing, dispensing and / or pin transferring. If the conductive die attach material is a solder bump, a predetermined pattern may be provided by forming the predetermined pattern of solder bumps by one of those that dispense and reflow solder paste, electroplate and / or dipping. Can be. If the conductive die attach material is a B-stage curable die epoxy and / or conductive polymer, it may be used for screen printing, dispensing, dispensing and reflow, layering and laser scribing, photolithography and / or fin transfer methods. The predetermined pattern can be provided by forming a B-stage curable die epoxy and / or conductive polymer.
    [14] In another embodiment of the present invention, a light emitting device die suitable for mounting on a submount includes a conductive substrate, such as a silicon carbide substrate, an active region of a gallium nitride base on a silicon carbide substrate, and an activity of a gallium nitride base opposite the substrate. A first electrode on the area is provided. In some embodiments, the active region of the first electrode and the gallium nitride base form a mesa having sidewalls. The second electrode is provided on a silicon carbide substrate opposite the gallium nitride active region. A predetermined pattern of conductive die attach material is provided on the first electrode opposite the gallium nitride active region to prevent the conductive die attach material from contacting the mesa and / or the sidewall of the substrate when the light emitting element is mounted to the submount.
    [15] The conductive die attach material of a predetermined pattern can provide a volume of die attach material that is less than the volume defined by the distance between the first electrode and the submount and the area of the first electrode. The predetermined pattern may be a single nodule of conductive die attach material on the first electrode. The predetermined pattern may be a plurality of bumps of conductive die attach material on the first electrode. The predetermined pattern may be a plurality of lines of conductive die attach material on the first electrode. The predetermined pattern may be a crisscross pattern of a conductive die attach material on the first electrode.
    [16] The conductive die attach material may be a B-stage curable die epoxy, a solder paste, a pattern of solder bumps, and / or a conductive polymer.
    [17] Submounts may be provided. In that case, the first electrode is mounted to the submount by a predetermined pattern of conductive die attach material.
    [18] Another embodiment of the invention provides a light emitting device suitable for mounting on a silicon carbide substrate, an active region of a gallium nitride base on the substrate, and a submount having a first electrode on an active region of the nitride base opposite the substrate do. The active region of the first electrode and the gallium nitride base form a mesa having sidewalls. The second electrode may be provided on the substrate opposite the gallium nitride active region. The B-stage conductive epoxy is provided on the first electrode opposite the gallium nitride active region.
    [19] B-stage conductive epoxy may be provided in a predetermined pattern. Certain patterns of B-stage conductive epoxy can provide a volume of B-stage conductive epoxy less than the volume defined by the distance between the first electrode and the submount and the area of the first electrode. The predetermined pattern may be a single nodule of B-stage conductive epoxy on the first electrode. The predetermined pattern may be a plurality of bumps of B-stage conductive epoxy on the first electrode. The predetermined pattern may further comprise a plurality of lines of B-stage conductive epoxy on the first electrode. The predetermined pattern may be a crisscross of B-stage doped epoxy on the first electrode.
    [20] Submounts may be provided. In such a case, the first electrode is mounted to the submount by a B-stage conductive epoxy.
    [21] In another embodiment of the invention, a light emitting device die has an active region of a gallium nitride base having at least one region of a first conductivity type and a first electrode electrically coupled to the active region of the gallium nitride base. do. The region of semiconductor material of the second conductivity type is electrically coupled to the active region of the gallium nitride base. The second conductivity type is opposite to the first conductivity type. The conductive die attach material of the predetermined pattern is used to substantially prevent the conductive die attach material from contacting the region of the semiconductor material of the second conductivity type when the light emitting element is mounted to the submount on the first electrode opposite the gallium nitride active region. It is composed.
    [22] The second electrode may be provided on the area of the semiconductor material of the second conductivity type. A substrate may be provided and an active region of gallium nitride base may be provided on the substrate. The first electrode and the second electrode may be on opposite sides of the substrate or may be on the same side of the substrate. The substrate may be insulating or conductive. In a particular embodiment of the invention, the substrate is a silicon carbide substrate.
    [31] The invention will be described in more detail hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. However, the invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. Moreover, the various layers and regions shown in the figures are schematically illustrated. As will be appreciated by those skilled in the art, reference herein to a layer formed “on” of a substrate or other layer may refer to a layer formed directly on top of the substrate or other layer, or another layer formed on or above the substrate or other layer, or It may refer to the layer involved. Accordingly, the present invention is not limited to the distances and relative sizes shown in the accompanying drawings.
    [32] Embodiments of the invention have a light emitting element, such as an LED die, using an electrode of a light emitting element such as a p-electrode and / or a die attach material that can be applied to the submount or package prior to packaging the light emitting element. It provides a connection of a light emitting device to a submount or package in a flip-chip configuration. The die attach material may be used to form a conductive bond between the light emitting element and the submount without forming a parasite diode that shunts the p-n diode of illumination. In some embodiments, shunted diodes can be avoided by preventing the conductive adhesive from substantially flowing during curing. In another embodiment, shunted diodes can be avoided by preventing the conductive adhesive from contacting a region of the device having a conductivity type that is opposite to the conductivity type of the region where the conductive adhesive provides contact. Thus, for example, if the conductive adhesive provides contact with respect to the P-type contact of the device, shunted diodes can be avoided by preventing the conductive adhesive from contacting the n-type region of the device. If the conductive adhesive provides contact for the n-type contact of the device, then shunted diodes can be avoided by preventing the conductive adhesive from contacting the p-type region of the device.
    [33] In another embodiment of the present invention wherein the conductive adhesive is a solder, the conductive adhesive may facilitate extracting heat from the device when the device is mounted in a flip-chip configuration. Such heat extraction may be beneficial for high power devices such as devices that may be suitable for use in white light applications. Moreover, although the present invention is described herein with reference to devices having contacts on basically opposite sides of the device, embodiments of the present invention may also be beneficial for devices having both contacts on the same side of the device. In such a case, the conductive adhesive can be provided in such a way that the conductive adhesive of the contact does not form a shunted diode by contacting the area of the device with the conductive type opposite to that of the contact being made. Moreover, the conductive adhesive of the two contacts does not contact each other.
    [34] Embodiments of the present invention herein reside on an n-type SiC substrate 10 and are electrically coupled to an n-type layer 14, a p-type layer 16, and a p-type layer. It is described with reference to a GaN-based LED having an electrode 18. However, the present invention should not be construed as limited to such a structure. Thus, reference herein to conductive die attach material that shorts the n-type regions 10, 14 is provided for illustrative purposes only. Thus, reference to shorting n-type regions 10 and 14 may be considered as reference to other layers in other device structures (eg, quantum wells and / or multiples). Accidental contact with a barrier layer die attach material in a quantum well device will result in damage to performance, reliability or other device characteristics.
    [35] The light emitting device used in the embodiment of the present invention may be a gallium nitride based LED or laser fabricated on a silicon carbide substrate, such as those manufactured and marketed by Cree of Durham, NC. For example, the present invention is disclosed in U.S. Pat. It may be suitable for use with LEDs and / or lasers as disclosed in 5,338,944, 5,210,051, 5,027,168, 4,966,862, and / or 4,918,497, which are incorporated by reference as disclosed herein. Other suitable LEDs and / or lasers are described in US Patent Provisional Application No. 60,294,378 "Light Emitting Diode Structures with Superlattice Structures and Multi-Quantum Wells", US Patent Provisional Application No. 60 / 294,445 "Multi-Quantum Light Emitting Diode Structures", and US Patents Provisional Application No. 60 / 294,308 "Light Emitting Diode Structure with Superlattice Structure" (filed May 30, 2001, respectively) and US Patent Application No. 10 / 140,796 "Nitride base of group III with quantum wells and superlattice The light emitting diode structure, the quantum well structure of the nitride base of group III, and the superlattice structure of the nitride base of group III "(filed May 7, 2002), and US Patent Provisional Application No. 10 / 057,82" light extraction Light emitting diodes having modified substrates and methods for manufacturing the same "(July 23, 2001) and US Patent Application No. 10 / 057,82" Light emitting diodes having modified substrates for light extraction and manufacturing methods thereof " (25 January 2002 ) It is disclosed in, which are incorporated herein as if set forth herein.
    [36] In a particular embodiment of the invention, the light emitting device can have a p-electrode which provides a reflective layer for reflecting light generated in the active region back through the device. Structures related to reflective p-electrodes are disclosed in US patent application Ser. No. 10 / 057,82, "Light Emitting Diodes with Modified Substrates for Light Extraction, and Methods for Manufacturing the Same" (filed Jan. 25, 2002). , Which is incorporated herein by reference as disclosed herein.
    [37] The LEDs and / or lasers may be configured to operate in a configuration of “flip-chips” such that irradiation of light occurs through the substrate. In such embodiments, the substrate can be patterned to improve the light output of the device, for example, US Provisional Application No. 60 / 307,235 "light-emitting diodes in which the substrate is modified for light extraction, and methods of manufacturing the same. "(July 23, 2001) and US patent application Ser. No. 10 / 057,82" light-emitting diodes with modified substrates for light extraction and methods of making them "(January 25, 2002) same.
    [38] In a particular embodiment of the invention, the die attach material may be provided as a pattern on the p-electrode of a gallium nitride based light emitting element formed on a silicon carbide substrate. As used herein, the term pattern means covering a portion of the surface on which the die attach material is disposed rather than all of the surface. In such embodiments, the pattern can be selected to substantially prevent the conductive die attach material from flowing to the sidewall of the gallium nitride device to short-circuit the active region of the device. In other embodiments, the pattern may be selected to prevent the conductive adhesive from substantially flowing during curing. Examples of conductive die attach materials in suitable patterns are shown in FIGS. 3A-3D. As shown in FIG. 3A, a single nodule of die attach material 30 is provided on the p-electrode 18 of the light emitting element on the substrate 10. 3B shows die attach material 30 formed in an array of nodules on p-electrode 18. 3C shows die attach material 30 formed in an array of lines on p-electrode 18. FIG. 3D shows die attach material 30 formed in a crisscross or " X " pattern on p-electrode 18. FIG. Other patterns can be employed without departing from the invention. In some embodiments, the pattern of conductive die attach material provides less space for the die attach material than the space defined by the distance between the light emitting element and the submount and the area of the p-electrode of the light emitting element.
    [39] The particular technique for providing a pattern of conductive die attach material may depend on the conductive die attach material. Suitable die attach materials include B-stage curable die epoxy (or “B-stage epoxy”), solder pastes, patterns of solder bumps, and / or conductive polymers. Embodiments of the present invention include a method of applying a die attach material to an LED die or wafer and also include an LED die having a die attach material deposited thereon. Other embodiments include a method of patterning a die attach material over an LED die or applying the patterned die attach material to an LED die or wafer, further comprising an LED die resulting therefrom.
    [40] As described above, the die attach material may comprise a standard B-stage epoxy. Such epoxies are commercially available from, for example, Emerson Cumming, Abelstik, Dexter, Diemat, and Epotek. In particular Abelstick's RP333-3 epoxy, Dexter's BMI-519, and Emerson Cumming's LA-9843-28 epoxy are suitable B stage epoxies. In some embodiments of the invention, the epoxy has the following properties.
    [41] * B stage curable;
    [42] Electrically conductive;
    [43] * Can withstand water (during later saw cutting operations of the wafer);
    [44] * Physical stiffness sufficient to withstand subsequent processing operations (eg, mounted on and detached from the tape).
    [45] In one embodiment, the B-stage epoxy need not be electrically conductive, and a separate electrically conductive path can be provided. The die attach material may comprise a conductive polymer such as CB028 manufactured by DuPont.
    [46] The process of manufacturing the light emitting device according to the invention will now be described with reference to the flow chart of FIG. 4. As shown in FIG. 4, a GaN based light emitting device, as described above, is fabricated on a SiC substrate (block 100). In such fabrication, ohmic contacts are formed on the opposite side of the wafer after depositing the desired epitaxial layers on the SiC wafer prior to dicing. The wafer is patterned with LEDs, for example by etching to form a plurality of mesas. In some embodiments, a passivation layer is formed to protect the epitaxial layer, which is described in US Patent Application 60 / 352,941 "Method of LED Die Attachment and Resultant Structure," filed Jan. 30, 2002. And the disclosure is incorporated herein as disclosed herein. However, even in such embodiments using conventional methods, there may be a possibility that the die attach material may be in contact with the substrate, for example where the substrate has been cut or broken, thereby forming a segmented diode. . Likewise, if the passivation layer is somewhat damaged, for example in areas where the substrate is broken, accidental contact can be made at such sites.
    [47] After fabrication of the light emitting device, the die attach material is formed in a predetermined pattern on the p-electrode of the LED (block 105). If a B-stage epoxy or conductive polymer is used, any of the following techniques may be used (or combination of techniques if necessary) to deposit it.
    [48] Screen printing: In these embodiments, a B-stage epoxy or polymer is applied on the p-electrode by screen printing using automated vision control. Screen printing and mechanical vision systems are known in the art and will therefore not be described herein any further. A suitable screen printing machine for this application is an SPM screen printer manufactured by MPM. If screen printing is used, the epoxy should be able to screen print to the appropriate dimensions. In some embodiments, the epoxy can be screen printed with a minimum feature size of about 4 mils.
    [49] * Distribution. In such embodiments, the B-stage epoxy is dispensed directly from the source to the desired location on the wafer or submount. Such embodiments may be used depending on the type of epoxy used and may include pneumatic distribution and / or positive displacement distribution through pin transfer, screw auger or piston action.
    [50] * Layer formation and laser scribing. In these embodiments, the side of the p-electrode of the wafer is coated with B-stage epoxy as a whole, and laser scribing is used to selectively remove unwanted epoxy.
    [51] Photolithography. In these embodiments, the photosensitive B-stage epoxy is applied to the p-electrode side of the wafer and photolithography techniques are used to selectively remove unwanted epoxy.
    [52] Other techniques for selectively providing a pattern of B-stage epoxy may also be used.
    [53] Once the B-stage epoxy has been deposited, it is pre-cure to solidify it. Typical heating ranges for precure are 50 to 150 ° C. Preferably, precure occurs at a temperature of 85 ° C. or less so as not to damage other materials used in the manufacturing process, such as mounting tape.
    [54] As mentioned above, other conductive die attach materials may be used in certain embodiments of the present invention. For example, solder paste can be used as the die attach material. Solder pastes generally comprise a solder metal or alloy such as Au / Ge, Pb / Sn, Au / Sn or In mixed with solvents and / or binders to form the paste. The solder paste may be applied by screen printing, dispensing or pin transfer as described above in connection with the epoxy. In certain embodiments of the invention where solder is used as the die attach material, pin transfer techniques can be used to provide solder dots as a pattern of die attach material. For example, about 0.2 mm of solder dots formed by pin transfer techniques can be used to attach the device to the submount.
    [55] Likewise, the die attach material may have solder bumps formed on the p-electrode. Solder bumps are generally provided with a binder or solvent free solder metal and can be deposited, for example, by dispensing the solder paste and subsequent reflow, electroplating and / or dipping.
    [56] In any case, after the conductive die attach material pattern is provided on the p-electrode of the device on the wafer, the wafer is cut and / or cut and broken using conventional techniques to separate into individual dies. (Block 110). Since sawing can be performed under a flow of deionized (DI) water, in some embodiments conductive die attach materials, such as B-stage epoxy, may contain water as well as mechanical stresses imposed from cutting and fracture. Withstand Individual dies may be secured to adhesive tape rolls to facilitate automated packaging. In addition, a group of dies in units can be provided, which is disclosed in US patent application Ser. No. 10 / 058,369, "Cluster Package of Light-Emitting Diode," filed Jan. 28, 2002, and the disclosures thereof. Is incorporated herein.
    [57] Individual dies may then be attached to the submount using conductive die attach material on the p-electrode. For example, when final packaging is performed on a die using a B-stage epoxy as the conductive die attach material (ie, when the die is mounted on a submount or package), the die is in place on the submount. It can be set and heated to the final curing temperature (typically above 150 ° C.). This causes the epoxy to reflow, creating a permanent connection between the LED chip and the submount. However, due to the conductive die attach material used, the pattern of the material on the p-electrode and / or the pressure used during bonding, the conductive material does not flow onto the sidewalls of the mesa and / or the substrate of the device, whereby the active area of the device Produces a shunted diode parallel to the. A wirebond connection is then made to the n-electrode.
    [58] While embodiments of the invention are shown in FIG. 4 in which the die attach material is provided on the p-electrode of the device, alternatively, the die attach material may be applied directly in the desired pattern on the package or submount or It can be applied directly to both the submount and p-electrode. In such embodiments, the submount is heated to the final curing temperature and the LED chip is pressed onto the submount. Since the B-stage epoxy is used in place of the less viscous conventional epoxy, the n-type layers of the active region of the device are less likely to contact the epoxy.
    [59] 5 shows an LED mounted according to embodiments of the present invention. As shown in FIG. 5, the epoxy 30 of the die attach material is disposed between the p-electrode 18 and the submount 24 but is not in contact with the n-type layer 14 or substrate 10 of the device. Do not. Thus, the volume of die attach material 30 is less than the volume defined by the distance between p-electrode 18 and submount 24 and the area of p-electrode 18.
    [60] FIG. 6 shows the substrate 10 and the p-electrode 18 of the light emitting device, on which rows of bumps of the conductive die attach material 30 were formed via deposition, patterning, plating and / or other techniques. FIG. 7 is a front view of the light emitting device of FIG. 6. After deposition of the bumps 30, the LED is placed on the submount and the device is heated at a temperature sufficient to reflow the bumps 30. In some embodiments, flux can be applied as part of the reflow process. The reflow temperature depends on the specific metal or alloy used. For example, an alloy containing a high percentage of Sn may have a melting point of less than 200 ° C., while an alloy with a low percentage of Sn has a melting point of 350 ° C. or more. In some embodiments, the bumps are at increased temperature, while the surface tension prevents the bumps from outflowing or wetting on the substrate 10 or n-type layer 14 of the LED. do. In other embodiments, non-wet patterns and / or solder dams may be used to control the outflow.
    [61] After the bumps are melted, the device is cooled, whereby the LED is bonded to the submount 24. 8 illustrates an LDE mounted in accordance with these embodiments of the present invention. As shown in FIG. 8, bumps of the die attach material epoxy 30 are disposed between the p-electrode 18 and the submount but do not contact the substrate 10 or the n-type layer 14 of the device. Thus, the volume of die attach material 30 (eg, solder bumps) is less than the volume defined by the distance between p-electrode 18 and submount 24 and the area of p-electrode 18. Thus, no Schottky diode is made between the n-type portions of the LED and the solder bumps.
    [62] In the drawings and specification, exemplary preferred embodiments of the invention have been disclosed, and specific terms have been employed, but they are used only in a generic and exemplary sense and are not for the purpose of limitation, the scope of the invention is the appended claims Is disclosed.
    [63] It can be applied in the field of LED of the present invention.
    权利要求:
    Claims (63)
    [1" claim-type="Currently amended] A method of mounting a light emitting device having a gallium nitride base light emitting region on a silicon carbide substrate in a flip-chip configuration,
    Mounting the electrode of the emissive region of the gallium nitride base to the submount using a B-stage curable die epoxy.
    [2" claim-type="Currently amended] The method of claim 1,
    The step of mounting,
    Forming a pattern of B-stage curable die epoxy on at least one electrode and / or submount; And,
    Attaching the electrodes and the submounts in the emissive region of the gallium nitride base to each other using a B-stage curable die epoxy.
    [3" claim-type="Currently amended] The method of claim 2,
    Forming a pattern of the B-stage curable die epoxy comprises applying the B-stage curable die epoxy to the electrode by screen printing.
    [4" claim-type="Currently amended] The method of claim 3, wherein
    Screen printing provides an application resolution of about 4 mils of B-stage curable die epoxy.
    [5" claim-type="Currently amended] The method of claim 2,
    Forming a predetermined pattern of B-stage curable die epoxy comprises dispensing the B-stage epoxy to desired locations of the electrode.
    [6" claim-type="Currently amended] The method of claim 2,
    Forming a predetermined pattern of B-stage curable die epoxy includes:
    Coating the electrode with B-stage epoxy; And,
    Selectively removing the B-stage epoxy from the electrode to provide the desired pattern.
    [7" claim-type="Currently amended] The method of claim 6,
    The optional removal step comprises laser scribing of the B-stage epoxy to selectively remove the epoxy to provide the desired pattern.
    [8" claim-type="Currently amended] The method of claim 6,
    The B-stage epoxy comprises a photosensitive B-stage epoxy, wherein forming the desired pattern of B-stage curable die epoxy comprises selectively removing the epoxy using photolithography to provide the desired pattern. How to feature.
    [9" claim-type="Currently amended] The method of claim 2,
    Forming a predetermined pattern of B-stage curable die epoxy comprises pin transferring the B-stage epoxy to locations on the electrode to provide the predetermined pattern.
    [10" claim-type="Currently amended] The method of claim 2,
    Forming a pattern of the B-stage curable die epoxy after the precuring the B-stage epoxy.
    [11" claim-type="Currently amended] The method of claim 10,
    Precuring the B-stage epoxy is characterized by precuring the B-stage epoxy using a temperature of about 50 to about 150 ° C.
    [12" claim-type="Currently amended] The method of claim 10,
    Pre-curing the B-stage epoxy comprises pre-curing the B-stage epoxy using a temperature of about 85 ° C.
    [13" claim-type="Currently amended] The method of claim 2,
    Attaching the light emitting regions and submounts of the gallium nitride base to each other using a predetermined pattern of B-stage curable die epoxy:
    Placing the light emitting element in a submount; And,
    Heating the B-stage epoxy to the final curing temperature so that the B-stage epoxy reflows.
    [14" claim-type="Currently amended] The method of claim 13,
    The heating step comprises heating the B-stage epoxy to a temperature of at least about 150 ° C.
    [15" claim-type="Currently amended] The method of claim 2,
    And wherein the predetermined pattern comprises a single nodule of B-stage epoxy on the electrode.
    [16" claim-type="Currently amended] The method of claim 2,
    And wherein the predetermined pattern comprises bumps of a plurality of B-stage epoxy on the electrode.
    [17" claim-type="Currently amended] The method of claim 2,
    And wherein the predetermined pattern comprises a plurality of lines of B-stage epoxy on the electrode.
    [18" claim-type="Currently amended] The method of claim 2,
    And the predetermined pattern comprises a crisscross pattern of B-stage epoxy on the electrode.
    [19" claim-type="Currently amended] A method of attaching a light emitting element die and a submount to each other in a flip-chip configuration, wherein the light emitting element die has an electrode on a mesa and a mesa configuration on a substrate.
    Forming a predetermined pattern of conductive die attach material over at least one of the electrode and the submounts;
    Attaching the light emitting element die and the submount to each other with a conductive die attach material therebetween;
    Wherein a predetermined pattern of conductive die attach material is selected to prevent the conductive die attach material from contacting the sidewalls of the mesa during attaching.
    [20" claim-type="Currently amended] The method of claim 19,
    A conductive pattern of die attach material of a predetermined pattern provides a volume of die attach material less than the volume defined by the distance between the electrode and the submount and the area of the electrode.
    [21" claim-type="Currently amended] The method of claim 19,
    And the predetermined pattern comprises a single nodule of conductive die attach material on the electrode.
    [22" claim-type="Currently amended] The method of claim 19,
    And wherein the predetermined pattern comprises a plurality of bumps of conductive die attach material on the electrode.
    [23" claim-type="Currently amended] The method of claim 19,
    And wherein the predetermined pattern comprises a plurality of lines of conductive die attach material on the electrode.
    [24" claim-type="Currently amended] The method of claim 19,
    And wherein the predetermined pattern has a crisscross pattern of conductive die attach material on the electrode.
    [25" claim-type="Currently amended] The method of claim 19,
    The conductive die attach material comprises at least one of a B-stage curable die epoxy, a solder paste, a pattern of a solder pump, and / or conductive polymers.
    [26" claim-type="Currently amended] The method of claim 19,
    The conductive die attach material comprises a solder paste, and wherein forming the predetermined pattern comprises forming the predetermined pattern of solder paste by at least one of screen printing, dispensing and / or pin transfers. .
    [27" claim-type="Currently amended] The method of claim 19,
    The conductive die attach material has solder bumps, and the step of forming the predetermined pattern comprises the step of forming a solder bump of the desired pattern by dispensing and reflowing, electroplating and / or dipping. How to feature.
    [28" claim-type="Currently amended] The method of claim 19,
    The conductive die attach material comprises at least one of a B-stage curable die epoxy and / or conductive polymers, wherein forming the desired pattern includes screen printing, dispensing, layering and laser scribing, photolithography. And / or forming at least one predetermined pattern of B-stage curable die epoxy and / or conductive polymer by at least one of the pin transfers.
    [29" claim-type="Currently amended] Conductive substrates;
    An active region of gallium nitride base on the conductive substrate;
    CLAIMS 1. A first electrode on an active region of a nitride base opposite a conductive substrate, comprising: a first electrode forming a mesa having sidewalls between the first electrode and the gallium nitride base;
    A second electrode on the conductive substrate opposite the gallium nitride active region; And,
    Of a predetermined pattern on the first electrode opposite the active region of gallium nitride, which substantially prevents the conductive die attach material from contacting at least one of the sidewalls of the substrate and mesa when the light emitting element die is mounted to the submount. A light emitting element die comprising a conductive die attach material.
    [30" claim-type="Currently amended] The method of claim 29,
    And wherein the conductive substrate comprises a silicon carbide substrate.
    [31" claim-type="Currently amended] The method of claim 29,
    And wherein the predetermined pattern of conductive die attach material provides a volume of die attach material that is less than the volume defined by the distance between the first electrode and the submount and the area of the first electrode.
    [32" claim-type="Currently amended] The method of claim 29,
    And wherein the predetermined pattern comprises a single nodule of conductive die attach material on the first electrode.
    [33" claim-type="Currently amended] The method of claim 29,
    The predetermined pattern includes a plurality of bumps of a conductive die attach material on the first electrode.
    [34" claim-type="Currently amended] The method of claim 29,
    And wherein the predetermined pattern comprises a plurality of lines of conductive die attach material on the first electrode.
    [35" claim-type="Currently amended] The method of claim 29,
    And the predetermined pattern comprises a crisscross pattern of a conductive die attach material on the first electrode.
    [36" claim-type="Currently amended] The method of claim 29,
    And wherein the conductive die attach material comprises at least one of a B-stage curable die epoxy, a solder paste, a pattern of solder bumps, and / or conductive polymers.
    [37" claim-type="Currently amended] The method of claim 29,
    And further comprising a submount, wherein the first electrode is mounted to the submount by a predetermined pattern of conductive die attach material.
    [38" claim-type="Currently amended] Board;
    An active region of gallium nitride base on the substrate;
    A first electrode on the active region of the nitride base opposite the substrate;
    And a B-stage conductive epoxy on the first electrode opposite the gallium nitride active region.
    [39" claim-type="Currently amended] The method of claim 38,
    And wherein the active region of the first electrode and the gallium nitride base form a mesa with sidewalls.
    [40" claim-type="Currently amended] The method of claim 38,
    The substrate is a conductive substrate, and the die further includes a second electrode on the conductive substrate opposite the gallium nitride active region.
    [41" claim-type="Currently amended] The method of claim 38,
    The substrate is an insulating substrate, and the die further comprises a second electrode on the conductive substrate in terms of a substrate, such as a gallium nitride active region.
    [42" claim-type="Currently amended] The method of claim 38,
    And wherein the conductive substrate comprises a silicon carbide substrate.
    [43" claim-type="Currently amended] The method of claim 38,
    And wherein the B-stage conductive epoxy is on the first electrode in a predetermined pattern.
    [44" claim-type="Currently amended] The method of claim 43,
    And wherein the predetermined pattern of conductive die attach material provides a volume of die attach material that is less than the volume defined by the distance between the first electrode and the submount and the area of the first electrode.
    [45" claim-type="Currently amended] The method of claim 43,
    And wherein the predetermined pattern comprises a single nodule of B-stage conductive epoxy on the first electrode.
    [46" claim-type="Currently amended] The method of claim 43,
    And wherein the predetermined pattern comprises a plurality of bumps of B-stage conductive epoxy on the first electrode.
    [47" claim-type="Currently amended] The method of claim 43,
    And wherein the predetermined pattern comprises a plurality of lines of B-stage conductive epoxy on the first electrode.
    [48" claim-type="Currently amended] The method of claim 43,
    Wherein the predetermined pattern has a crisscross pattern of B-stage conductive epoxy on the first electrode.
    [49" claim-type="Currently amended] The method of claim 38,
    Further comprising a submount, wherein the first electrode is mounted to the submount by a B-stage conductive epoxy.
    [50" claim-type="Currently amended] An active region of gallium nitride base having at least one region of a first conductivity type;
    A first electrode electrically coupled to the active region of the gallium nitride base;
    A region of semiconductor material of a second conductivity type electrically coupled to an active region of a gallium nitride base, the second conductivity type being an area of the semiconductor material opposite to the first conductivity type;
    A predetermined pattern of conductive die attach material on a first electrode opposite the gallium nitride active region, wherein the predetermined pattern is such that the conductive die attach material is in contact with the region of the semiconductor material of the second conductive type when the light emitting element die is mounted to the submount. Conductive die attach material configured to substantially prevent the light emitting element die for flip-chip mounting.
    [51" claim-type="Currently amended] 51. The method of claim 50 wherein
    And further comprising a second electrode on a region of semiconductor material of a second conductivity type.
    [52" claim-type="Currently amended] The method of claim 51, wherein
    Further comprising a substrate, wherein the active region of the gallium nitride base is on the substrate.
    [53" claim-type="Currently amended] The method of claim 52, wherein
    And wherein the first and second electrodes are on opposite sides of the substrate.
    [54" claim-type="Currently amended] The method of claim 52, wherein
    And wherein the first electrode and the second electrode are on the same side of the substrate.
    [55" claim-type="Currently amended] The method of claim 52, wherein
    And the substrate comprises a silicon carbide substrate.
    [56" claim-type="Currently amended] 51. The method of claim 50 wherein
    And wherein the conductive die attach material of the predetermined pattern provides a volume of die attach material that is less than the volume defined by the distance between the first electrode and the submount and the area of the first electrode.
    [57" claim-type="Currently amended] 51. The method of claim 50 wherein
    And wherein the predetermined pattern comprises a single nodule of conductive die attach material on the first electrode.
    [58" claim-type="Currently amended] 51. The method of claim 50 wherein
    A conductive die attach material includes solder.
    [59" claim-type="Currently amended] 51. The method of claim 50 wherein
    And wherein the predetermined pattern includes a plurality of bumps of conductive die attach material on the first electrode.
    [60" claim-type="Currently amended] 51. The method of claim 50 wherein
    The predetermined pattern includes a plurality of lines of conductive die attach material on the first electrode.
    [61" claim-type="Currently amended] 51. The method of claim 50 wherein
    And wherein the predetermined pattern comprises a crisscross pattern of conductive die attach material on the first electrode.
    [62" claim-type="Currently amended] 51. The method of claim 50 wherein
    And wherein the conductive die attach material comprises at least one of a B-stage curable die epoxy, a solder paste, a pattern of solder bumps, and / or conductive polymers.
    [63" claim-type="Currently amended] 51. The method of claim 50 wherein
    And further comprising a submount, wherein the first electrode is mounted to the submount by a predetermined pattern of conductive die attach material.
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    同族专利:
    公开号 | 公开日
    EP1417722A2|2004-05-12|
    EP2262017A2|2010-12-15|
    US6888167B2|2005-05-03|
    CN1557025A|2004-12-22|
    US20050017256A1|2005-01-27|
    US7608860B2|2009-10-27|
    EP1417722B1|2011-10-05|
    WO2003010833A3|2004-03-11|
    US7259033B2|2007-08-21|
    CN100392874C|2008-06-04|
    EP2262017A3|2017-01-04|
    AT527698T|2011-10-15|
    CA2454797A1|2003-02-06|
    JP2005510043A|2005-04-14|
    US20030045015A1|2003-03-06|
    WO2003010833A2|2003-02-06|
    TW578276B|2004-03-01|
    US20070241360A1|2007-10-18|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2001-07-23|Priority to US30731101P
    2001-07-23|Priority to US60/307,311
    2002-06-27|Priority to US10/185,252
    2002-06-27|Priority to US10/185,252
    2002-07-22|Application filed by 크리 인코포레이티드, 크리 마이크로웨이브 인크.
    2002-07-22|Priority to PCT/US2002/023120
    2004-04-06|Publication of KR20040029381A
    优先权:
    申请号 | 申请日 | 专利标题
    US30731101P| true| 2001-07-23|2001-07-23|
    US60/307,311|2001-07-23|
    US10/185,252|US6888167B2|2001-07-23|2002-06-27|Flip-chip bonding of light emitting devices and light emitting devices suitable for flip-chip bonding|
    US10/185,252|2002-06-27|
    PCT/US2002/023120|WO2003010833A2|2001-07-23|2002-07-22|Flip chip bonding of light emitting devices and light emitting devices suitable for flip-chip bonding|
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