Bonding equipment and bonding structure

Abstract

The utility model provides a bonding device and a bonding structure, and relates to the technical field of semiconductor packaging. The bonding equipment comprises a base, a transfer arm and a first optical camera device, one side, facing the transfer arm, of the base is used for arranging a driving chip; the transfer arm is provided with a transparent area, and the transparent area is used for arranging a micro LED chip; the first optical camera device is located on the side, opposite to the base, of the transparent area, bonding of the micro LED chip and the driving chip cannot be hindered, and meanwhile first alignment information is obtained through the transparent area in the bonding process and comprises position information of a first mark on the micro LED chip and position information of a second mark on the driving chip after primary bonding; therefore, the position of the base and the position of the transfer arm are adjusted based on the first alignment information, deviation is reduced, and the bonding yield is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor packaging, in particular to a bonding device and a bonding structure. Background Art

[0002] Micro-LED (Micro light emitting diode) usually refers to a micro device that arranges Micro-LED chips or chip arrays on a TFT board or CMOS board according to certain rules based on the traditional LED flip-chip structure, so that each chip can be addressed and driven individually to emit light, thereby achieving full-color display.

[0003] Existing Micro-LED bonding equipment usually has a low bonding yield problem due to large deviation. Utility Model Content

[0004] In order to solve the problems existing in the prior art, one of the purposes of the present invention is to provide a bonding device.

[0005] The utility model provides the following technical solutions:

[0006] A bonding device includes a base, a transfer arm, and a first optical camera device;

[0007] The side of the base facing the transfer arm is used to arrange a driving chip;

[0008] The transfer arm has a transparent area, and the transparent area is used to place the micro LED chip;

[0009] The first optical camera device is located on the side of the transparent area facing away from the base, and the first optical camera device is used to obtain first alignment information through the transparent area. The first alignment information includes position information of the first mark on the micro LED chip and the second mark on the driver chip after one bonding.

[0010] As a further optional solution for the bonding device, the base and the transfer arm are further used to perform secondary bonding on the micro LED chip and the driver chip after position adjustment based on the first alignment information.

[0011] As a further optional solution for the bonding device, the transparent area is provided with a transparent first adsorption member, and the first adsorption member is used to adsorb the micro LED chip.

[0012] As a further optional solution for the bonding device, the first optical camera device can move freely, and the moving range of the first optical camera device is not less than the range of the micro LED chip.

[0013] As a further optional solution for the bonding device, the bonding device also includes a second optical camera device, which is used to obtain second alignment information, and the second alignment information includes position information of the first mark and the second mark before one bonding.

[0014] As a further optional solution for the bonding device, the second optical camera device can move between the base and the transfer arm to obtain the second alignment information.

[0015] As a further optional solution for the bonding device, a second adsorption member is provided on a side of the base facing the transfer arm, and the second adsorption member is used to adsorb the driver chip.

[0016] Another object of the present invention is to provide a bonding structure.

[0017] The utility model provides the following technical solutions:

[0018] A bonding structure is formed by bonding using the above-mentioned bonding device, wherein the bonding structure includes a micro LED chip and a driver chip connected by a bonding layer, the micro LED chip is provided with a first mark, and the driver chip is provided with a second mark, the first mark is used to determine the position information of the micro LED chip during the bonding process, and the second mark is used to determine the position information of the driver chip during the bonding process.

[0019] As a further optional solution to the bonding structure, the micro LED chip has a display area, and a plurality of first marks are provided, and the plurality of first marks are distributed around the display area.

[0020] As a further optional solution to the bonding structure, the micro LED chip is arranged in a square shape, the first marks are respectively provided at the top corners of the micro LED chip, and the display area is located in the middle of the micro LED chip.

[0021] The embodiments of the present invention have the following beneficial effects:

[0022] In the aforementioned bonding device, at least a portion of the transfer arm is made of a transparent material, thereby forming a transparent area for positioning the micro-LED chip. Because the first optical camera is located on the side of the transparent area facing away from the base, it does not hinder the bonding of the micro-LED chip and the driver chip. Therefore, during the bonding process, the first optical camera can remain on the side of the transparent area facing away from the base. After a single bond, the first optical camera can capture first alignment information through the transparent area. This allows the base and transfer arm to adjust their positions based on this first alignment information, thereby reducing misalignment and improving bonding yield.

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 A schematic diagram of a bonding alignment process in related art is shown;

[0026] Figure 2 A schematic structural diagram of a bonding device provided by an embodiment of the present utility model is shown;

[0027] Figure 3 A schematic structural diagram of a micro LED chip in a bonding structure provided by an embodiment of the present invention is shown;

[0028] Figure 4 A schematic structural diagram of a driver chip in a bonding structure provided by an embodiment of the present utility model is shown.

[0029] Description of main component symbols:

[0030] 100-base; 110-second adsorption member; 200-transfer arm; 210-transparent area; 220-first adsorption member; 300-first optical camera device; 400-second optical camera device; 500-driver chip; 510-second mark; 600-micro LED chip; 610-first mark; 620-display area; 700-optical camera. DETAILED DESCRIPTION

[0031] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0032] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. Conversely, when an element is referred to as being "directly on" another element, there is no intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only.

[0033] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, indirect connection through an intermediate medium, internal communication between two components, or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used in the template description herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0036] Micro-LED (micro light emitting diode) refers to a micro-device that reduces the size of LED chips to 100 microns or even less than 50 microns based on the traditional flip-chip LED structure. This miniaturization and arraying of RGB (red, green, and blue) micro-LED chips (or LED chip arrays) are arranged according to a specific pattern on a TFT or CMOS board, allowing each chip to be addressed and individually driven to emit light, thus achieving full-color display. Compared with current LED and OLED display devices, micro-LEDs offer advantages such as fast response, wide color gamut, high PPI, and low energy consumption. Their power consumption is approximately 10% of that of LEDs and 50% of that of OLEDs.

[0037] In related technologies, the Micro-LED bonding method is as follows:

[0038] See also Figure 1 A driver chip 500 (such as an IC chip or carrier chip) is attached to the upper surface of the base 100, while a micro LED chip 600 is attached to the lower surface of the transfer arm 200. An optical camera 700 is then moved between the base 100 and the transfer arm 200 to image the mark alignment points on the driver chip 500 and micro LED chip 600. The marks on the driver chip 500 and micro LED chip 600 are then moved to align them.

[0039] However, due to the limitations of the machine bonding method, mark alignment can only be performed before bonding. During the bonding process, the optical camera 700 needs to be moved, and the mark position cannot be monitored in real time. At the same time, factors such as the machine flatness, material warpage, and machine accuracy will cause the mark alignment position to change during bonding, resulting in larger deviations and the inability to ensure that the pixels of the micro LED chip 600 and the pixels of the driver chip 500 are accurately aligned (the accuracy is required to be around 0.5um). This will cause problems such as dense bad pixels, continuous bad pixels, uneven brightness, short circuits, and no lighting in the sample test after bonding, resulting in a low bonding yield.

[0040] For the above questions, please refer to Figure 2 This embodiment provides a bonding device for bonding a driver chip 500 to a micro LED chip 600 . The bonding device includes a base 100 , a transfer arm 200 , and a first optical camera device 300 .

[0041] Specifically, the side of the base 100 facing the transfer arm 200 is used to place the driving chip 500 .

[0042] The transfer arm 200 has a transparent area 210 , and the transparent area 210 is used to place the micro LED chip 600 .

[0043] In addition, the first optical camera device 300 is located on the side of the transparent area 210 facing away from the base 100. The first optical camera device 300 is used to obtain first alignment information through the transparent area 210. The first alignment information includes a first mark 610 on the micro LED chip 600 (see FIG. Figure 3 ) and the second mark 510 on the driver chip 500 (see Figure 4 ) position information after one bonding.

[0044] It can be understood that the micro LED chip 600 uses a sapphire substrate, so the first optical camera device 300 can not only identify the position information of the first mark 610 on the micro LED chip 600 through the transparent area 210 and the sapphire substrate, but also identify the position information of the second mark 510 on the driver chip 500 through the transparent area 210 and the sapphire substrate.

[0045] In the aforementioned bonding apparatus, at least a portion of the transfer arm 200 is made of a transparent material, thereby forming a transparent region 210 for positioning the micro LED chip 600. Because the first optical camera device 300 is located on the side of the transparent region 210 facing away from the base 100, it does not hinder the bonding of the micro LED chip 600 to the driver chip 500. Therefore, during the bonding process, the first optical camera device 300 can remain on the side of the transparent region 210 facing away from the base 100. After a single bonding operation, the first optical camera device 300 can capture first alignment information through the transparent region 210. This allows the base 100 and transfer arm 200 to adjust their positions based on this first alignment information, thereby reducing misalignment and improving bonding yield.

[0046] For example, the transfer arm 200 may be partially made of transparent glass to form the transparent area 210. Alternatively, the entire transfer arm 200 may be made of transparent glass, which is not limited in this embodiment.

[0047] Furthermore, after the base 100 and the transfer arm 200 are adjusted in position based on the first alignment information, they perform secondary bonding on the micro LED chip 600 and the driver chip 500 .

[0048] In other words, the bonding process of the driver chip 500 and the Micro LED chip 600 using the bonding equipment described above includes two steps: primary bonding and secondary bonding. After the primary bonding, the first optical camera 300 obtains first alignment information, and the base 100 and transfer arm 200 adjust their positions based on this first alignment information to eliminate any misalignment caused by the primary bonding process. Subsequently, the base 100 and transfer arm 200 perform a secondary bonding process on the Micro LED chip 600 and the driver chip 500.

[0049] In some embodiments, the transparent region 210 is provided with a transparent first adsorption member 220 , and the first adsorption member 220 is used to adsorb the micro LED chip 600 .

[0050] Exemplarily, one side of the first adsorption member 220 is adsorbed and fixed to the transparent region 210 of the transfer arm 200 , and the other side of the first adsorption member 220 is adsorbed and fixed to the micro LED chip 600 .

[0051] The micro LED chip 600 is fixed by the first adsorption member 220 in a vacuum adsorption manner, so that the micro LED chip 600 can be quickly fixed and the product can be quickly separated from the transfer arm 200 after the bonding is completed.

[0052] At the same time, the first adsorption component 220 is also made of transparent material, so the first optical camera device 300 can identify the position information of the first mark 610 on the micro LED chip 600 and the position information of the second mark 510 on the driver chip 500 through the transparent area 210 of the transfer arm 200, the first adsorption component 220 and the sapphire substrate.

[0053] The adsorption area of the vacuum hole on the first adsorption member 220 is 40%-50% of the area of the micro LED chip 600 .

[0054] In some embodiments, a second adsorption member 110 is provided on a side of the base 100 facing the transfer arm 200 , and the second adsorption member 110 is used to adsorb the driving chip 500 .

[0055] Exemplarily, one side of the second adsorption member 110 is adsorbed and fixed on the base 100 , and the other side of the second adsorption member 110 is adsorbed and fixed on the driving chip 500 .

[0056] The second adsorption member 110 is used to fix the driver chip 500 in a vacuum adsorption manner, so that the driver chip 500 can be quickly fixed and the product can be quickly separated from the base 100 after the bonding is completed.

[0057] The adsorption area of the vacuum holes on the second adsorption member 110 is 40%-50% of the area of the driving chip 500 .

[0058] In some embodiments, the bonding device further includes a second optical camera device 400, which is used to obtain second alignment information. The second alignment information includes position information of the first mark 610 and the second mark 510 before one bonding.

[0059] Specifically, when the driver chip 500 and the micro LED chip 600 are bonded using the above-mentioned bonding equipment, the base 100 vacuum-adsorbs the second adsorption component 110, and the second adsorption component 110 further adsorbs and fixes the driver chip 500. At the same time, the transfer arm 200 vacuum-adsorbs the first adsorption component 220, and the first adsorption component 220 further adsorbs and fixes the micro LED chip 600.

[0060] Subsequently, before primary bonding, the second optical camera device 400 identifies the positional information of the first mark 610 on the micro LED chip 600 and the positional information of the second mark 510 on the driver chip 500, thereby obtaining second alignment information. The base 100 and transfer arm 200 perform mark alignment based on the second alignment information obtained by the second optical camera device 400, and after alignment, primary bonding is performed.

[0061] For example, the base 100 is positioned below the transfer arm 200. With the top surface of the base 100 as the zero reference line, the height of the driver chip 500 is approximately 300 μm, the height of the second adsorbent 110 is approximately 50 μm, and the primary bonding height is set to 351-352 μm. During a primary bonding, the micro LED chip 600 contacts the driver chip 500. Furthermore, during a primary bonding, the temperature of the first adsorbent 220 is set to approximately 195°C, the temperature of the second adsorbent 110 is set to approximately 100°C, the pressing force is 10-20 N, and the pressing time is approximately 90 seconds.

[0062] After the first bonding is complete, the pressing is stopped and the first alignment information is acquired using the first optical camera device 300. The base 100 and the transfer arm 200 are adjusted based on the first alignment information acquired by the first optical camera device 300. After the mark alignment is completed again, a second bonding is performed. The height of the second bonding is set to approximately 350.5-351.5 μm, and the pressing force is 20-30 N.

[0063] Typically, the precision deviation after a single bonding step is 1-1.5μm. Since the micro LED chip 600 already touches the driver chip 500 after the primary bonding step, the bonding area between the micro LED chip 600 and the driver chip 500 is heated and melted during the secondary bonding step. The micro LED chip 600 is then fine-tuned to move it 0.5-1μm before further pressing. This completes the bonding between the micro LED chip 600 and the driver chip 500, keeping the deviation within the 0.5μm control line. During the secondary bonding process, there is no need to separate the micro LED chip 600 from the driver chip 500.

[0064] Exemplarily, both the first optical camera device 300 and the second optical camera device 400 utilize CCD cameras. For example, a commercially available CCD camera with a magnification of 200-500 times and 5-10 million pixels can be used. The CCD camera has an outer edge size of 2.5 cm in diameter and a height of 9 cm. It is easy to use and can be observed and controlled via software.

[0065] Furthermore, the bonding device further includes a first fixing device. A first optical camera device 300 is disposed on the first fixing device, and the first fixing device is used to drive the first optical camera device 300 to move freely, and the movement range of the first optical camera device 300 is not less than the range of the micro LED chip 600.

[0066] Exemplarily, the first optical camera device 300 moves along the first plane relative to the transfer arm 200 , and the range of the micro LED chip 600 specifically refers to the projection range of the micro LED chip 600 on the first plane.

[0067] The first plane is parallel to the surface of the transfer arm 200 facing the base 100 .

[0068] It can be understood that moving the first optical camera device 300 along the first plane relative to the transfer arm 200 is beneficial for the first optical camera device 300 to more accurately identify the position information of the first mark 610 and the position information of the second mark 510, and reduce the error caused by the angular deviation between the optical axis of the first optical camera device 300 and the first mark 610, and between the optical axis of the first optical camera device 300 and the second mark 510.

[0069] In addition, since the range of movement of the first optical camera device 300 along the first plane relative to the transfer arm 200 is not less than the projection range of the micro LED chip 600 on the first plane, the first optical camera device 300 is driven to move relative to the transfer arm 200 by the first fixing device, so that the first optical camera device 300 can be moved to face any first mark 610, thereby minimizing errors and improving accuracy.

[0070] Exemplarily, the projection range of the micro LED chip 600 on the first plane is the size of the micro LED chip 600 , which is approximately 2.8*2.0 cm, and the moving range of the first optical camera device 300 is approximately 5.0*5.0 cm.

[0071] In some embodiments, the transfer arm 200 is provided with a corresponding fixing device for driving the transfer arm 200 to move relative to the base 100 , and the fixing device of the transfer arm 200 and the first fixing device are separated from each other and do not interfere with each other.

[0072] In other embodiments, the first fixing device may also be provided on the transfer arm 200 , and the first optical camera device 300 may be encapsulated inside the transfer arm 200 or located on the surface of the transfer arm 200 facing away from the base 100 .

[0073] Furthermore, the bonding device further includes a second fixing device on which a second optical camera device 400 is disposed. The second fixing device is used to drive the second optical camera device 400 to move between the base 100 and the transfer arm 200 to obtain second alignment information.

[0074] It can be understood that before a bonding, the second fixing device drives the second optical camera device 400 to move between the base 100 and the transfer arm 200, which is conducive to the second optical device to more accurately identify the position information of the first mark 610 and the position information of the second mark 510, thereby improving the accuracy of the first mark alignment.

[0075] After the base 100 and the transfer arm 200 are mark-aligned based on the position information of the first mark 610 and the position information of the second mark 510 recognized by the second optical camera device 400, the second fixing device drives the second optical camera device 400 to move away from between the base 100 and the transfer arm 200, so as to prevent the second optical camera device 400 from obstructing the primary bonding of the micro LED chip 600 and the driver chip 500.

[0076] In summary, when the aforementioned bonding equipment bonds the driver chip 500 to the micro-LED chip 600, it first performs mark alignment using the second optical camera device 400 to initiate a single bonding cycle. After the primary bonding cycle is complete, the first optical camera device 300 performs mark alignment and offset adjustment, followed by a secondary bonding cycle. This ensures that the mark alignment offset after bonding is less than 0.5 μm. Compared to conventional bonding methods, the aforementioned bonding equipment can monitor mark offset in real time, preventing excessive mark alignment offset after bonding. This can further prevent problems such as dense bad pixels, continuous bad pixels, uneven brightness, and short circuits, thereby improving the product's bonding yield.

[0077] Please also refer to Figure 3 and Figure 4 This embodiment also provides a bonding structure, which is bonded using the above-mentioned bonding device. The bonding structure includes a micro LED chip 600 and a driver chip 500 connected by a bonding layer.

[0078] The micro LED chip 600 is provided with a first mark 610, which is used to determine the position of the micro LED chip 600 during the bonding process. The driver chip 500 is provided with a second mark 510, which is used to determine the position of the driver chip 500 during the bonding process.

[0079] In some embodiments, the micro LED chip 600 has a display region 620. Pins are distributed in an array within the display region 620. The pins generally have a height of 1.4-1.6 μm and a diameter of 2.2-2.6 μm.

[0080] In addition, a plurality of first marks 610 are provided, and the plurality of first marks 610 are distributed around the display area 620. After the first optical camera device 300 and the second optical camera device 400 identify the position information of the first marks 610, the position of the display area 620 can be more accurately determined based on the position information of the first marks 610, thereby improving the bonding yield.

[0081] Exemplarily, the micro LED chip 600 is arranged in a square shape, and first marks 610 are respectively provided at the top corners of the micro LED chip 600 , and the display area 620 is located in the middle of the micro LED chip 600 .

[0082] Correspondingly, the driver chip 500 is also arranged in a square shape. The second mark 510 corresponds to the position of the first mark 610 and is respectively located at the top corner of the driver chip 500.

[0083] In all examples shown and described herein, any specific values should be interpreted as merely exemplary and not limiting, and thus other examples of the exemplary embodiments may have different values.

[0084] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0085] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the scope of the present invention, all of which fall within the scope of protection of the present invention.

Claims

1. A bonding device, characterized in that: It includes a base, a transfer arm and a first optical camera device; The side of the base facing the transfer arm is used to arrange a driving chip; The transfer arm has a transparent area, and the transparent area is used to place the micro LED chip; The first optical camera device is located on the side of the transparent area facing away from the base, and the first optical camera device is used to obtain first alignment information through the transparent area. The first alignment information includes position information of the first mark on the micro LED chip and the second mark on the driver chip after one bonding.

2. The bonding device according to claim 1, wherein The base and the transfer arm are further used to perform secondary bonding on the micro LED chip and the driver chip after position adjustment based on the first alignment information.

3. The bonding device according to claim 1, wherein: The transparent area is provided with a transparent first adsorption member, and the first adsorption member is used for adsorbing the micro LED chip.

4. The bonding device according to claim 1, wherein: The first optical camera device can move freely, and the moving range of the first optical camera device is not less than the range of the micro LED chip.

5. The bonding device according to any one of claims 1 to 4, characterized in that: The bonding equipment further includes a second optical camera device, which is used to obtain second alignment information, where the second alignment information includes position information of the first mark and the second mark before one bonding.

6. The bonding device according to claim 5, wherein: The second optical camera device can move between the base and the transfer arm to obtain the second alignment information.

7. The bonding device according to any one of claims 1 to 4, characterized in that: A second adsorption component is provided on a side of the base facing the transfer arm, and the second adsorption component is used to adsorb the driving chip.

8. A bonding structure, characterized in that The bonding structure is formed by bonding using the bonding equipment described in any one of claims 1 to 7, wherein the bonding structure includes a micro LED chip and a driver chip connected by a bonding layer, the micro LED chip is provided with a first mark, and the driver chip is provided with a second mark, the first mark is used to determine the position information of the micro LED chip during the bonding process, and the second mark is used to determine the position information of the driver chip during the bonding process.

9. The bonding structure according to claim 8, characterized in that The micro LED chip has a display area, and a plurality of first marks are provided, and the plurality of first marks are distributed around the display area.

10. The bonding structure according to claim 9, wherein: The micro LED chip is arranged in a square shape, the first marks are respectively arranged at the top corners of the micro LED chip, and the display area is located in the middle of the micro LED chip.

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