Flip chip packaging method and packaging device

Abstract

The invention belongs to the technical field of LED (light-emitting diode) packaging, and relates to a flip chip packaging method, which comprises the following steps of: S1, mounting a plurality of flip chips on a bracket to realize chip fixation; the electrode of the flip chip is connected with the metal sheet on the bracket in a reflow soldering manner; s2, the edge of the support is filled with reflective glue, and the reflective glue is cured and formed through baking; s3, placing red fluorescent powder on the upper surface of each flip chip; s4, mixing and stirring green fluorescent powder in transparent silica gel, and then coating the green fluorescent powder in the bowl cup of the bracket in a dispensing manner; the invention also relates to a flip chip packaging device. According to the invention, a discrete control type support design is adopted, and a flip packaging scheme can be supported to realize independent control of a single wafer so as to realize packaging intellectualization; red fluorescent powder is placed on the surface of the flip chip to reduce reabsorption of white light; and the proportion of the red fluorescent powder and the green fluorescent powder can be controlled to realize full color temperature adjustment.

Description

Technical Field

[0001] The invention belongs to the technical field of LED packaging, and in particular relates to a flip chip packaging method and a packaging device. Background Art

[0002] With the development of society, people's demands for lighting have become diversified. In addition to high requirements for luminous efficiency, people also hope that lighting has intelligent dimming capabilities, which poses a challenge to traditional outdoor lighting packaging devices. At present, outdoor lighting products generally use upright LED chip solutions. Since circuit connection requires metal bonding wires, it is impossible to achieve intelligent control of single chips. The voltage of upright chips increases significantly under high power, making it difficult to improve luminous efficiency. However, flip-chip chips can maintain lower voltage at high power due to their excellent droop effect, resulting in higher luminous efficiency.

[0003] At present, outdoor lighting mainly uses EMC / SMC / PCT packaging combined with upright chips, and conventional outdoor brackets cannot achieve independent control of a single chip. The packaging of flip-chip LED chips is mainly used in COB or CSP packaging forms. Currently, these two forms cannot be directly used in outdoor application scenarios, and there is no packaging and design of PLCC brackets based on EMC / SMC / PCT materials, so they cannot be directly used in outdoor high-power lighting.

[0004] In view of the above problems, it is urgent to improve the existing packaging process and structure. The present invention proposes a new LED packaging method and device. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a flip chip packaging method and packaging device, which adopts a discrete control bracket design, can support the flip chip packaging scheme to realize independent control of a single chip, so as to realize intelligent packaging; red phosphor is placed on the surface of the flip chip to reduce the reabsorption of white light, which can improve the light efficiency; and on the basis of independent control, the ratio of red phosphor and green phosphor can be flexibly controlled to realize full color temperature adjustment. The present invention is implemented by the following scheme:

[0006] A flip chip packaging method comprises the following steps:

[0007] Step S1: installing a plurality of flip-chips on a support to achieve die bonding; and connecting the electrodes of the flip-chips to the metal sheets on the support by reflow soldering to form a circuit;

[0008] Step S2: Filling the edge of the bracket with reflective glue and curing it by baking;

[0009] Step S3: placing red phosphor on the upper surface of each flip chip;

[0010] Step S4: After mixing and stirring the green fluorescent powder in the transparent silica gel, the mixture is applied to the bowl of the bracket by dispensing, and then cured by baking.

[0011] Preferably, the bracket adopts a discrete control type, and one side of the bracket includes a plurality of fixing positions, each of which includes a first groove and a second groove, and the first groove and the second groove are respectively used to accommodate the positive and negative poles of the flip chip; the other side is provided with a plurality of grooves, and each of the grooves is respectively installed with a solder pad.

[0012] Preferably, the number of the pads is the same as the number of the flip-chip chips, and further includes transition pads, which are common poles or non-common poles, and the pads are separated to achieve independent control of each flip-chip chip.

[0013] Preferably, in step S3, placing red phosphor on the upper surface of each flip chip is specifically:

[0014] The red fluorescent powder is mixed and stirred in transparent silica gel to form a thin film, which is then coated on the upper surface of each flip chip by dispensing.

[0015] Preferably, in step S3, placing red phosphor on the upper surface of each flip chip is specifically:

[0016] The red fluorescent powder is placed on the upper surface of each flip chip by spraying.

[0017] Preferably, the red phosphors placed on the flip chip have different concentrations to achieve full color temperature adjustment.

[0018] Preferably, when one or more of the flip-chips are turned off, the red phosphor and / or green phosphor on the surface thereof stops being excited, and the excitation ratio of the green phosphor to the red phosphor in the bracket bowl changes to achieve full color temperature regulation.

[0019] The present application also relates to a flip chip packaging device, which is manufactured using the above flip chip packaging method, and the flip chip packaging device comprises:

[0020] A support, wherein a bowl and a cup are formed in the support;

[0021] A plurality of flip chips mounted in the bowl of the support;

[0022] Reflective glue, which is filled between the inner wall of the bowl and the flip chip;

[0023] Red phosphor, which is placed on the upper surface of each flip chip;

[0024] The green fluorescent powder is coated on the bowl of the bracket in a dispensing manner.

[0025] Preferably, the bracket adopts a discrete control type, and one side of the bracket includes a plurality of fixing positions, each of which includes a first groove and a second groove, and the first groove and the second groove are respectively used to install the positive and negative poles of the flip chip; the other side is provided with a plurality of grooves, and each of the grooves is respectively installed with a solder pad.

[0026] Preferably, the number of the pads is the same as the number of the flip-chip chips, and also includes transition pads, which are common poles or non-common poles. Independent control of each flip-chip chip can be achieved through separate pads; the number of flip-chip chips on the bracket is 4 or 6.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The present invention adopts a discrete control bracket design, which can support the flip-chip packaging solution to realize independent control of a single chip, so as to realize intelligent packaging; through discrete control, the detection of a single chip can also be realized, solving the problem of the inability to detect leakage after polycrystalline series connection in the prior art, thereby improving product quality.

[0029] (2) The present invention can realize the square arrangement of flip-chip chips through a discrete control bracket, and can be compatible with a design of four or six chips in parallel, thereby achieving the characteristics of two voltage compatibility;

[0030] (3) The present invention reduces the reabsorption of white light by placing red phosphor on the surface of the flip chip, thereby reducing the loss of light efficiency and improving the light efficiency.

[0031] (4) The present invention places red phosphor on the surface of the flip chip, and the concentration of the red phosphor can be set to different levels. Green phosphor is further dispensed in the bowl of the bracket. Combined with the independent control of the chip by the discrete bracket, the color temperature can be effectively adjusted by adjusting the number of flip chip switches. When one or more flip chips are turned off, the red phosphor and / or green phosphor on its surface stops being excited, and the ratio of the green phosphor to the red phosphor in the bowl of the bracket changes to achieve full color temperature adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the solid crystal in step S1 of the present invention;

[0033] Figure 2 It is a schematic diagram of reflow soldering in step S1 of the present invention;

[0034] Figure 3 This is a schematic diagram of applying reflective glue in step S2 of the present invention;

[0035] Figure 4 This is a schematic diagram of baking reflective adhesive in step S2 of the present invention;

[0036] Figure 5 This is a schematic diagram of dispensing red fluorescent powder in step S3 of the present invention;

[0037] Figure 6 This is a schematic diagram of dispensing green phosphor in step S4 of the present invention;

[0038] Figure 7 This is a schematic diagram of the baking process in step S4 of the present invention;

[0039] Figure 8 It is one of the schematic diagrams of the packaging device of the present invention;

[0040] Fig. 9 It is a schematic diagram of placing red phosphors of different concentrations according to the present invention;

[0041] Fig.10 A schematic diagram of a conventional front-mount chip packaging structure;

[0042] Fig.11 is a schematic diagram of a separate bracket of the present invention;

[0043] Fig.12 It is a schematic diagram of the flip chip and the bracket being connected by soldering according to the present invention;

[0044] Fig.13 It is a schematic diagram of applying red fluorescent powder when using a discrete bracket of the present invention;

[0045] Fig.14 It is a schematic diagram of applying green fluorescent powder when using a discrete bracket of the present invention;

[0046] Fig.15 It is a schematic diagram of the pad arrangement of four parallel-connected crystals using a discrete support of the present invention;

[0047] Fig.16 It is a schematic diagram of the first circuit connection of four crystals in parallel using a discrete support of the present invention;

[0048] Fig.17 It is a schematic diagram of the pad arrangement of six parallel-connected crystals in a discrete support of the present invention;

[0049] Fig.18 It is a schematic diagram of the first circuit connection of the present invention using six crystals in parallel on a discrete support;

[0050] Fig.19 This is a schematic diagram of the second circuit connection of the present invention using six crystals in parallel on a discrete support.

[0051] The names corresponding to the reference numerals are:

[0052] 100 bracket, 200 flip chip, 300 reflective adhesive, 400 red phosphor, 500 green phosphor;

[0053] 101 fixed position, 1011 first groove, 1012 second groove, 102 groove;

[0054] 1 first pad, 2 second pad, 3 transition pad, 4 fourth pad, 5 fifth pad. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0056] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0057] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "mounted / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] Embodiment 1

[0059] This embodiment relates to a flip chip packaging method, such as Figure 1-8 As shown, the following steps are included:

[0060] Step S1: installing a plurality of flip-chips on a support to achieve die bonding; and connecting the electrodes of the flip-chips to the metal sheets on the support by reflow soldering to form a circuit;

[0061] Step S2: Filling the edge of the bracket with reflective glue and curing it by baking;

[0062] Step S3: placing red phosphor on the upper surface of each flip chip;

[0063] Step S4: After mixing and stirring the green fluorescent powder in the transparent silica gel, the mixture is applied to the bowl of the bracket by dispensing, and then cured by baking.

[0064] The present invention reduces the reabsorption of white light by placing red fluorescent powder on the surface of the flip chip, thereby reducing the problem of light efficiency loss and improving the light efficiency.

[0065] Furthermore, if Figure 11-14 As shown, the bracket adopts a discrete control type, and one side of the bracket includes a plurality of fixing positions, each of which includes a first groove and a second groove, and the first groove and the second groove are respectively used to accommodate the positive and negative poles of the flip chip; the other side is provided with a plurality of grooves, and each of the grooves is respectively installed with a solder pad.

[0066] In this way, the present invention adopts a discrete control bracket design, which can support the flip-chip packaging solution to realize independent control of a single chip to achieve intelligent packaging; through discrete control, the detection of a single chip can also be realized, solving the problem of the inability to detect leakage after polycrystalline series connection in the prior art, thereby improving product quality.

[0067] Furthermore, the number of the pads is the same as the number of the flip-chip chips, and also includes transition pads, through which the independent control of each flip-chip chip is achieved, that is, when the transition pads are included, the total number of all pads is one more than the total number of the flip-chip chips.

[0068] In one embodiment, if Figure 15-16 As shown, the number of flip-chips is equal to the sum of the number of left and right pads (first pad 1, fourth pad 4, second pad 2, fifth pad 5), and the middle part is the transition pad 3 which is not included. Specifically, it is the first circuit scheme of the present invention, in which the transition pad is set to a common polarity, and the independent control of the packaged chip can be achieved by separating the pads; Figure 15-16 As shown, by adopting the four-chip parallel connection mode and taking the transition pad 3 as the common pole, the independent control of the first pad 1, the fourth pad 4, the second pad 2 and the fifth pad 5 can be realized; specifically, during use, only the first pad 1 and the transition pad 3, the second pad 2 and the transition pad 3, the fourth pad 4 and the transition pad 3, the fifth pad 5 and the transition pad 3 can be connected, or the first pad 1, the fourth pad 4, the second pad 2, the fifth pad 5 and the transition pad 3 can be connected at the same time, so that the full parallel connection of the flip-chip and the flip-chip is realized so that the packaged device always maintains the voltage of a single chip.

[0069] In another embodiment, if Figure 17-18 As shown, by adopting the six-crystal parallel connection method and taking the transition parallel pad 84 as the common pole, the independent control of the first parallel pad 81, the second parallel pad 82, the third parallel pad 83, the fifth parallel pad 85, the sixth parallel pad 86 and the seventh parallel pad 87 can be realized, and the details are not repeated here.

[0070] In this way, the present invention can realize the compatibility of two voltages by using a design of four or even six chips in parallel when the flip-chip chips are arranged in a square shape through a discrete control bracket.

[0071] In another embodiment, if Fig.19 As shown, it is the second circuit scheme of the present invention, the transition pad element 33 is not used as a common polarity, that is, during the use of the packaged device, only the first chip pad 11 and the second chip pad 22, the second chip pad 22 and the fifth chip pad 55 are connected, or the first chip pad 11, the fourth chip pad 44 and the second chip pad 22, the fifth chip pad 55 are connected at the same time, which can realize the series connection of flip chips and flip chips to increase the voltage (specifically twice the voltage of a single chip).

[0072] The first and second circuit schemes mentioned above always have isolated circuits of a single chip, so both can achieve independent testing of a single chip, thus avoiding the problem of being unable to test device leakage due to the circuit not being isolated after two chips are connected in series.

[0073] In addition, regardless of the first or second circuit solution, independent control of some or all chips in the packaged device can be achieved, thereby achieving the purpose of color temperature adjustment. Different choices of circuit solutions only affect the span and quantity of color temperature adjustment.

[0074] Further, in the step S3, placing the red phosphor on the upper surface of each flip chip is specifically: mixing the red phosphor in transparent silica gel to form a thin film, and then applying it to the upper surface of each flip chip by dispensing. Alternatively, in the step S3, placing the red phosphor on the upper surface of each flip chip is specifically: placing the red phosphor on the upper surface of each flip chip by spraying.

[0075] Furthermore, the red phosphors placed on the flip-chips have different concentrations to achieve full color temperature adjustment. For example, in theory, placing red phosphors with the same concentration can achieve the same number of color temperature combinations as the number of flip-chips, such as 6 chips to achieve 6 color temperature combinations, while placing red phosphors with different concentrations can achieve more color temperature combinations, such as 6 flip-chips can achieve 63 color temperature combinations (calculated by the combination formula).

[0076] In this way, the present invention places red phosphor on the surface of the flip chip, and the concentration of the red phosphor can be set to different levels, and further glues green phosphor in the bowl of the bracket. Combined with the independent control of the chip by the discrete bracket, the color temperature can be effectively adjusted by adjusting the number of flip chip switches;

[0077] Furthermore, when one or more of the flip-chips are closed, the red phosphor and / or green phosphor on the surface thereof stops being excited, and the excitation ratio of the green phosphor to the red phosphor in the bracket bowl changes to achieve full color temperature regulation.

[0078] Embodiment 2

[0079] The present application also relates to a flip chip packaging device, which is manufactured using the flip chip packaging method described in the first embodiment. Figure 11-18 As shown, the flip chip packaging device comprises:

[0080] A support 100, wherein a bowl is formed in the support;

[0081] A plurality of flip chips 200 mounted in the bowl of the support 100;

[0082] Reflective adhesive 300, which is filled between the inner wall of the bowl and the flip chip 200;

[0083] Red phosphor 400, which is placed on the upper surface of each flip chip;

[0084] The green phosphor 500 is applied to the bowl of the bracket 100 by dispensing.

[0085] Specifically, the bracket adopts a discrete control type, one side of which includes a plurality of fixing positions, each of which includes a first groove 1011 and a second groove 1012, and the first groove 1011 and the second groove 1012 are respectively used to install the positive electrode and the negative electrode of the flip chip; the other side is provided with a plurality of grooves 102, each of which is respectively installed with a pad. Preferably, the bracket adopts EMC / SMC / PCT plastic packaging material.

[0086] Specifically, the number of pads is the same as the number of flip chips, and also includes transition pads 3; the pads are separated to achieve independent control of each flip chip. The number of flip chips on the bracket is 4 or 6, but not limited to 4 or 6, and the number of flip chips can be an even number, for example, 8 or 10, or more, so that more flip chips can be connected in parallel.

[0087] The above are only preferred specific implementations of the present invention; however, the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and improved concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A flip chip packaging method, characterized in that: The following steps are involved: Step S1: installing a plurality of flip-chips on a support to achieve die bonding; and connecting the electrodes of the flip-chips to the metal sheets on the support by reflow soldering to form a circuit; Step S2: Filling the edge of the bracket with reflective glue and curing it by baking; Step S3: placing red phosphor on the upper surface of each flip chip; Step S4: After mixing and stirring the green fluorescent powder in the transparent silica gel, the mixture is applied to the bowl of the bracket by dispensing, and then cured by baking.

2. The flip chip packaging method according to claim 1, characterized in that: The bracket adopts a discrete control type, and one side of the bracket includes a plurality of fixing positions, each of which includes a first groove and a second groove, and the first groove and the second groove are respectively used to accommodate the positive electrode and the negative electrode of the flip chip; the other side is provided with a plurality of grooves, and each of the grooves is respectively installed with a solder pad.

3. The flip chip packaging method according to claim 2, characterized in that: The number of the pads is the same as the number of the flip-chip chips, and the pads also include transition pads. The transition pads are common poles or non-common poles. The pads are separated to achieve independent control of each flip-chip chip.

4. The flip chip packaging method according to claim 1, characterized in that: In step S3, placing red phosphor on the upper surface of each flip chip is specifically: The red fluorescent powder is mixed and stirred in transparent silica gel to form a thin film, which is then coated on the upper surface of each flip chip by dispensing.

5. The flip chip packaging method according to claim 1, characterized in that: In step S3, placing red phosphor on the upper surface of each flip chip is specifically: The red fluorescent powder is placed on the upper surface of each flip chip by spraying.

6. The flip chip packaging method according to claim 1, characterized in that: The red phosphors placed on the flip chip have different concentrations to achieve full color temperature regulation.

7. The flip chip packaging method according to claim 3, characterized in that: When one or more of the flip chips are closed, the red phosphor and / or green phosphor on the surface thereof stops being excited, and the excitation ratio of the green phosphor to the red phosphor in the bracket bowl changes to achieve full color temperature regulation.

8. A flip chip packaging device, characterized in that: The flip chip packaging device is manufactured using the flip chip packaging method according to any one of claims 1 or 4-7, and the flip chip packaging device comprises: A support, wherein a bowl and a cup are formed in the support; A plurality of flip chips mounted in the bowl of the support; Reflective glue, which is filled between the inner wall of the bowl and the flip chip; Red phosphor, which is placed on the upper surface of each flip chip; The green fluorescent powder is coated on the bowl of the bracket in a dispensing manner.

9. The flip chip packaging device according to claim 8, characterized in that: The bracket adopts a discrete control type, and one side of it includes a plurality of fixing positions, each of which includes a first groove and a second groove, and the first groove and the second groove are respectively used to install the positive and negative electrodes of the flip chip; the other side is provided with a plurality of grooves, and each of the grooves is respectively installed with a solder pad.

10. The flip chip package device according to claim 9, characterized in that: The number of the pads is the same as the number of the flip-chip chips, and also includes transition pads, which are common poles or non-common poles. Independent control of each flip-chip chip can be achieved through separate pads; the number of flip-chip chips on the bracket is 4 or 6.

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