Wafer level packaging method and packaging structure of OLED chip

Abstract

The application provides an OLED chip wafer-level packaging method and packaging structure, and relates to the technical field of semiconductor packaging. The OLED chip wafer-level packaging method comprises the following steps: providing a light-transmitting cover plate and a wafer; the wafer is provided with a plurality of light-emitting areas; the outer periphery of the light-emitting area is provided with an electrode; and a preset interval is arranged between the electrode and the light-emitting area. A plurality of grooves are formed on one side of the light-transmitting cover plate; the depth of the grooves is smaller than the thickness of the light-transmitting cover plate; and a mounting part is formed between the grooves. The wafer and the light-transmitting cover plate are bonded; the light-emitting area corresponds to the mounting part one by one and is pressed together. The light-transmitting cover plate is cut along the edge of the mounting part, the groove structure is removed, and a wafer with a light-transmitting patch is formed; the projection of the light-transmitting patch on the wafer does not overlap with the electrode. The wafer is singulated to form single chips. The method is beneficial to improving the packaging efficiency and the packaging yield.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor packaging, and in particular to a wafer-level packaging method and packaging structure of an OLED chip. BACKGROUND

[0002] In the prior art, the OLED chip is packaged in a single-chip packaging form. That is, a barrier wall is formed around the chip by using a dry film or a glue layer, and then a single glass sheet prepared in advance is attached to the chip by dispensing glue. This method has low packaging efficiency and the glue is easy to overflow and contaminate the electrodes on the chip during the attaching process, thereby affecting the packaging yield. SUMMARY

[0003] The present application aims to provide a wafer-level packaging method and packaging structure of an OLED chip, which can improve the packaging efficiency and yield.

[0004] In a first aspect, the present application provides a wafer-level packaging method of an OLED chip, comprising:

[0005] A light-transmitting cover plate and a wafer are provided respectively, wherein the wafer is provided with a plurality of light-emitting areas, and an electrode is provided around the light-emitting area, and a preset interval is provided between the electrode and the light-emitting area;

[0006] A plurality of grooves are formed on one side of the light-transmitting cover plate, and the depth of the grooves is less than the thickness of the light-transmitting cover plate; and an attaching part is formed between the grooves;

[0007] The wafer and the light-transmitting cover plate are bonded, wherein the light-emitting areas correspond to the attaching parts one by one and are pressed together;

[0008] The light-transmitting cover plate is cut along the edges of the attaching parts to remove the groove structure, thereby forming a wafer with light-transmitting patches, and the projection of the light-transmitting patches on the wafer does not overlap with the electrodes;

[0009] The wafer is cut to form single-chip wafers.

[0010] In an optional embodiment, the step of bonding the wafer and the light-transmitting cover plate comprises:

[0011] Light-transmitting glue is formed on the light-emitting areas of the wafer and / or the attaching parts;

[0012] The wafer and the light-transmitting cover plate are pressed together, wherein the wafer is on the top and the light-transmitting cover plate is on the bottom.

[0013] In an optional embodiment, the step of pressing the wafer and the light-transmitting cover plate comprises:

[0014] The wafer and the light-transmitting cover plate are pre-pressed at room temperature and normal pressure.

[0015] pressing the wafer and the light-transmitting cover plate under vacuum environment and under warm and pressurized conditions.

[0016] In an optional embodiment, the step of pressing the wafer and the light-transmitting cover plate under vacuum environment and under warm and pressurized conditions comprises:

[0017] pressing under the first temperature and the first pressure for a first preset time and keeping for a second preset time;

[0018] pressing under the second temperature and the second pressure for a third preset time and keeping for a fourth preset time;

[0019] the second temperature is greater than the first temperature; and the second pressure is greater than the first pressure.

[0020] In an optional embodiment, in the step of forming a plurality of grooves on one side of the light-transmitting cover plate, the grooves are formed by sandblasting or etching;

[0021] If the sandblasting method is used, the step comprises at least two sandblasting processes; wherein the first sandblasting forms the grooves, and the second sandblasting polishes and corrects the groove walls; wherein the correction comprises correcting the inclination angle of the groove walls and the depth of the grooves.

[0022] In an optional embodiment, after the step of forming a plurality of grooves on one side of the light-transmitting cover plate, the method further comprises:

[0023] forming a drainage groove on the side wall of the groove.

[0024] In an optional embodiment, in the step of forming a plurality of grooves on one side of the light-transmitting cover plate, a positioning mark is formed on the side of the light-transmitting cover plate having the grooves.

[0025] In an optional embodiment, the step of bonding the wafer and the light-transmitting cover plate comprises:

[0026] forming a glue-containing groove on the mounting portion;

[0027] forming a light-transmitting glue on the mounting portion;

[0028] pressing the wafer and the light-transmitting cover plate.

[0029] In an optional embodiment, after the step of forming a glue-containing groove on the mounting portion, the method further comprises:

[0030] opening an overflow port on the groove wall of the glue-containing groove; the overflow port communicates the glue-containing groove and the groove.

[0031] In a second aspect, the present application provides a packaging structure made by the wafer level packaging method of the OLED chip as described in any of the preceding embodiments.

[0032] The wafer level packaging method of the OLED chip and the packaging structure provided by the embodiments of the present application have the following beneficial effects:

[0033] The wafer level packaging method of the OLED chip provided by the embodiments of the present application can bond a large piece of light-transmitting cover plate and a wafer, and can complete the bonding and mounting of the light-transmitting cover plate and multiple chips on the wafer at one time, thus being high in efficiency. In addition, a groove is formed on the light-transmitting cover plate before mounting, and the groove can accommodate excess glue during the mounting process, so as to avoid the diffusion of the excess glue to the edge of the light-emitting area of the chip and thus to avoid the pollution of the electrode. When the light-transmitting cover plate is cut, the electrode and the light-transmitting cover plate have a gap in the thickness direction due to the groove structure, so that the electrode is not damaged during the cutting process, and the cutting thickness is relatively thin, which is beneficial to improve the cutting efficiency and the fault tolerance of the cutting precision, and thus to improve the packaging yield.

[0034] The packaging structure provided by the embodiments of the present application is made by the wafer level packaging method of the OLED chip as described above, and is beneficial to improve the packaging efficiency and the packaging yield. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0036] Figure 1 The structure diagram of the light-transmitting cover plate in the wafer level packaging method of the OLED chip provided by the embodiments of the present application is shown in the following figure:

[0037] Figure 2 The structure diagram of the groove formed on the light-transmitting cover plate in the wafer level packaging method of the OLED chip provided by the embodiments of the present application is shown in the following figure:

[0038] Figure 3 The structure diagram of the groove formed on the light-transmitting cover plate in the wafer level packaging method of the OLED chip provided by the embodiments of the present application is shown in the following figure: Figure 2 The cross-sectional view of E-E in the figure is shown in the following figure:

[0039] Figure 4 The structure diagram of the side wall of the groove of the light-transmitting cover plate provided by the embodiments of the present application is shown in the following figure:

[0040] Figure 5 The structure diagram of the light-transmitting cover plate provided by the embodiments of the present application is shown in the following figure:

[0041] Figure 6 Structure diagram of the structure of the adhesive part of the light-transmitting cover plate provided in the embodiment of the present application, in which a glue accommodating groove is formed;

[0042] Figure 7 Structure diagram of the structure of the adhesive part of the light-transmitting cover plate provided in the embodiment of the present application, in which an overflow port is formed;

[0043] Figure 8 Structure diagram of the wafer in the wafer level packaging method of the OLED chip provided in the embodiment of the present application;

[0044] Figure 9 Structure diagram of the wafer in the wafer level packaging method of the OLED chip provided in the embodiment of the present application;

[0045] Figure 10 Structure diagram of the wafer in the wafer level packaging method of the OLED chip provided in the embodiment of the present application;

[0046] Figure 11 Structure diagram of the wafer in the wafer level packaging method of the OLED chip provided in the embodiment of the present application;

[0047] Figure 12 Structure diagram of the wafer in the wafer level packaging method of the OLED chip provided in the embodiment of the present application;

[0048] Figure 13 Structure diagram of the wafer in the wafer level packaging method of the OLED chip provided in the embodiment of the present application;

[0049] Figure 14 Structure diagram of the wafer in the wafer level packaging method of the OLED chip provided in the embodiment of the present application.

[0050] Icon: 110 - light-transmitting cover plate; 111 - groove; 1111 - side wall; 112 - adhesive part; 113 - drainage groove; 114 - positioning mark part; 115 - glue accommodating groove; 116 - overflow port; 117 - light-transmitting patch; 120 - wafer; 121 - light-emitting area; 122 - electrode; 130 - light-transmitting glue; 131 - overflow glue; 140 - first cutting piece; 150 - second cutting piece; 160 - substrate; 161 - pad; 162 - metal wire. DETAILED DESCRIPTION

[0051] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0052] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0053] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0054] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only used for differentiation and cannot be understood as indicating or implying relative importance.

[0055] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components must be absolutely horizontal or overhanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0056] In the description of the present application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0057] Some embodiments of the present application will be described in detail with reference to the drawings. The following embodiments and features of the embodiments described below can be combined with each other in the case of no conflict.

[0058] The wafer-level packaging method and packaging structure of the OLED chip provided by the embodiments of the present application can realize wafer-level packaging, greatly improving the efficiency compared with the single-chip packaging of the prior art. In addition, the overflow pollution of the electrodes in the bonding process of the light-transmitting cover plate and the wafer can be prevented, thereby improving the packaging yield.

[0059] The wafer-level packaging method of the OLED chip comprises the following steps.

[0060] Please refer to Figure 1 , step S1, providing a light-transmitting cover plate 110. The light-transmitting cover plate 110 can be a glass plate.

[0061] Optionally, a piece of white glass is prepared, and the dirt on the surface of the glass is removed by washing with alkaline medicine and hot water. According to the size of the wafer 120, the size of the white glass piece is approximately equal to the size of the wafer 120. Optionally, the round piece is 6 inches to 12 inches, and the thickness is 100 microns to 1000 microns.

[0062] In other embodiments, the light-transmitting cover plate 110 can also be made of other high-transparency materials, such as transparent polymer materials, transparent thin film composite materials, transparent ceramic materials, flexible ultra-thin glass or other emerging materials. Among them, the transparent polymer material includes but is not limited to at least one or more of polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and cyclic olefin polymer (COP). The transparent thin film composite material includes but is not limited to transparent polysiloxane or a multi-layer barrier thin film stacked by alternately stacking a polymer (such as PET) and an inorganic layer (aluminum oxide or silicon oxide). The transparent ceramic material includes but is not limited to sapphire (Al2O3 single crystal) or transparent aluminum oxide (polycrystalline Al2O3) and the like. Other emerging materials include but are not limited to graphene film or nanocellulose film and the like.

[0063] Please refer to Figure 2 and Figure 3 , step S2, forming a plurality of grooves 111 on one side of the light-transmitting cover plate 110, the depth of the grooves 111 being less than the thickness of the light-transmitting cover plate 110; and forming a mounting portion 112 between the plurality of grooves 111.

[0064] Optionally, the spacing between the plurality of grooves 111 is determined according to the distribution position of the chips on the wafer 120. The grooves 111 can be formed by sandblasting or etching. Of course, laser slotting or other methods can also be used, which are not limited here. In the present embodiment, the sandblasting method is used to form the grooves 111, which will be described below.

[0065] Optionally, a mask plate is prepared first, which is a steel plate designed with a specific pattern according to the distribution of the light-emitting area 121 of the chip on the wafer 120. The mask plate is placed on the light-transmitting cover plate 110, covering part of the area of the light-transmitting cover plate 110. The part of the light-transmitting cover plate 110 exposed from the mask plate is the sandblasting area. A large number of small steel balls are used to bombard the surface of the light-transmitting cover plate 110 to form the groove 111. During the bombardment process, the depth and angle of the groove 111 can be adjusted by adjusting the pressure and the number of steel balls. The mask plate can protect the non-sandblasting area of the light-transmitting cover plate 110. It can be understood that the non-sandblasting area includes the gap between the grooves 111, i.e., the formed mounting part 112.

[0066] Optionally, the angle of the groove 111 can be adjusted according to the product structure and space, which is generally 30° to 90°, and the preferred angle is 60°. The angle of the groove 111 refers to the angle formed by the side wall 1111 of the groove 111 and the surface of the light-transmitting cover plate 110, as shown by θ in Figure 3

[0067] Optionally, the depth of the groove 111 is L, which is greater than or equal to 5 microns and less than the thickness of the light-transmitting cover plate 110. In this way, it can be ensured that there is enough gap in the thickness direction between the electrode 122 and the light-transmitting cover plate 110 after mounting, which provides a safe cutting space for subsequent processes and prevents damage to the electrode 122 during cutting. It has a higher fault tolerance for cutting depth and is beneficial to improve the cutting yield.

[0068] In this embodiment, at least two sandblasting processes are included. The first sandblasting forms the groove 111, and the second sandblasting polishes and corrects the groove wall of the groove 111. The correction includes the correction of the inclination angle of the groove wall and the depth of the groove 111. The groove wall of the groove 111 includes the bottom wall and the side wall 1111. By polishing and correcting the bottom wall and the side wall 1111, the forming precision of the groove 111 can be improved, the form error can be reduced, the alignment accuracy in the subsequent bonding process can be improved, and the alignment offset between the electrode 122 and the groove 111 can be avoided. The amount is too large to damage the electrode 122 during cutting.

[0069] Please refer to Figure 4 ​Optionally, in the second sandblasting process or after the second sandblasting process, the micro-channel guide groove 113 can be formed on the side wall 1111 of the groove 111. The micro-channel guide groove 113 can play a role of guiding the overflowed glue, so that the overflowed glue flows along the guide groove 113 in the subsequent process, avoiding the pollution of the overflowed glue 131 to the electrode 122. In addition, the guide groove 113 adopts a micro-channel structure, has a certain capillary effect on the overflowed glue 131, can further improve the flowability of the overflowed glue 131 flowing into the groove 111, and has better guiding and directing effects, further avoiding the pollution of the overflowed glue 131 to the electrode 122, and improving the reliability of the electrode 122.

[0070] Please refer to Figure 5 Optionally, the positioning mark part 114 can also be formed in the sandblasting process, and serves as a positioning reference in the bonding process, improving the alignment accuracy in the subsequent bonding process, thereby improving the packaging yield. The positioning mark part 114 can be formed in the first or second sandblasting process, or can be formed in the first sandblasting and the second sandblasting respectively. The shape, size, number and distribution position of the positioning mark part 114 can be flexibly designed. In the embodiment, a corresponding positioning pattern can be designed on the mask plate, so that the positioning mark part 114 is formed in the process of forming the groove 111. The positioning mark part 114 can be a pit or a column different from the depth of the groove 111. Of course, the mask plate with the positioning pattern and the mask plate for forming the groove 111 pattern can be designed on the same mask plate body, or can be designed on two mask plates respectively, which is not limited here.

[0071] Please refer to Figure 6 Optionally, after the groove 111 is formed, the glue containing groove 115 is formed on the surface of the mounting part 112. The glue containing groove 115 can be an annular groove formed along the edge of each mounting part 112, or can be a pit or a plurality of strip grooves or a mesh groove arranged on the surface of the entire mounting part 112. The glue containing groove 115 has the functions of storing glue and preventing glue from overflowing, further preventing glue from overflowing. In addition, the glue containing groove 115 increases the contact area between the mounting part 112 and the glue, which is beneficial to improve the bonding force and the bonding reliability of the light-transmitting cover plate 110 and the wafer 120.

[0072] Please refer to Figure 7 Optionally, the groove wall of the glue containing groove 115 can be provided with an overflow port 116, so that the overflowed glue 131 flows out of the overflow port 116 and flows along the side wall 1111 of the groove 111, further avoiding the pollution of the overflowed glue 131 to the electrode 122 on the wafer 120. The overflow port 116 is lower than the groove opening of the glue containing groove 115, so that the excess overflowed glue 131 flows out of the overflow port 116 and does not spread from the groove opening of the glue containing groove 115 to the wafer 120 to pollute the electrode 122.

[0073] Step S3, providing a wafer 120. Please refer toFigure 8 The wafer 120 is provided with a plurality of light emitting areas 121, and the outer periphery of the light emitting area 121 is provided with an electrode 122, and there is a preset interval between the electrode 122 and the light emitting area 121.

[0074] In step S4, the wafer 120 and the light-transmitting cover plate 110 are bonded; wherein the light emitting area 121 corresponds to the mounting portion 112 one by one and is pressed.

[0075] Optionally, please refer to Figure 9 The light-transmitting glue 130 is formed on the light emitting area 121 of the wafer 120 and / or the mounting portion 112. The light-transmitting glue 130 can be preset only on the light emitting area 121 of the wafer 120, or only on the mounting portion 112 of the light-transmitting cover plate 110, or the light-transmitting glue 130 is formed on the light emitting area 121 of the wafer 120 and the mounting portion 112 of the light-transmitting cover plate 110 respectively. In the embodiment, the light-transmitting glue 130 is formed on the mounting portion 112 in advance. A layer of high-transmittance bonding glue is coated on the surface of the mounting portion 112 by silk-screen printing or rolling glue, and the thickness of the bonding glue is 1-10um. By controlling the thickness of the light-transmitting glue 130, the overflow of the glue can be reduced.

[0076] Please refer to Figure 10 and Figure 11 The wafer 120 and the light-transmitting cover plate 110 are pressed. The wafer 120 is on the top, and the light-transmitting cover plate 110 is on the bottom. In this way, the glue containing effect of the groove 111 can be effectively played. Even if the light-transmitting glue 130 overflows, the overflowed glue will only flow downward under the action of gravity, flow to the bottom of the groove through the side wall 1111 of the groove 111, and will not overflow to the wafer 120 on the top and pollute the electrode 122.

[0077] It should be noted that in the bonding process, the positioning mark portion 114 is used to first accurately position the wafer 120 and the light-transmitting cover plate 110, and the positioning accuracy can be controlled within 20um. Then the permanent bonding is performed by a pressing machine. The pressing machine first pre-presses the light-transmitting cover plate 110 at normal temperature and pressure, and the pre-pressing process can discharge most of the gas in the light-transmitting glue 130. Due to the setting of the groove 111, the discharged gas can also be contained, and the residual gas in the light-transmitting glue 130 can be reduced. It should be noted that if the gas cannot be discharged, the gas residue is easy to form bubbles in the glue, which will cause the formation of cavities at the bonding position of the light-transmitting cover plate 110 and the wafer 120, and even cause the glue to be layered, affecting the packaging reliability and product light emitting quality.

[0078] After pre-pressing, the lamination is performed by increasing temperature and applying pressure in a vacuum environment, which can further expel air bubbles in the transparent adhesive 130 and reduce gas residues in the adhesive. The temperature and pressure can ensure the uniformity of the transparent adhesive 130 in the functional area of the chip, i.e., the light-emitting area 121, and effectively improve the light-emitting quality. During the lamination process, if there is excess adhesive 131, the excess adhesive 131 will flow to the groove 111 of the transparent cover plate 110 and will not contaminate the electrode 122. The groove 111 of the transparent cover plate 110 will be cut and removed later, and the presence of the excess adhesive 131 in the groove 111 will not affect the yield and light-emitting quality of the final packaging structure.

[0079] Optionally, the lamination is performed at the first temperature and the first pressure for a first preset time and maintained for a second preset time. The lamination is performed at the second temperature and the second pressure for a third preset time and maintained for a fourth preset time. The second temperature is greater than the first temperature, and the second pressure is greater than the first pressure.

[0080] Specifically, the lamination method in a vacuum environment is as follows:

[0081] 1. First, heat the upper and lower hot plates to 60-70°C, with a pressure of zero, and maintain for 3-5 min;

[0082] 2. Maintain the temperature of the upper and lower hot plates at 60-70°C, apply a first pressure of 200-500 mbar, and maintain for 3-5 min;

[0083] 3. Heat the upper and lower hot plates to about 80-90°C, apply a second pressure of 1000-1500 mbar, and maintain for 10-15 min;

[0084] 4. Gradually cool to room temperature 25°C, release the vacuum, and gradually reduce the pressure to zero to complete the lamination step in a vacuum environment.

[0085] Please refer to Figure 12 , step S5, cut the transparent cover plate 110 along the edge of the mounting portion 112 to remove the groove 111 structure and form a wafer 120 with transparent patches 117. The projection of the transparent patch 117 on the wafer 120 does not overlap the electrode 122.

[0086] The cutting of the light-transmitting cover plate 110 can be performed by laser cutting, cutter cutting, etc. Alternatively, the first cutting member 140 is used to cut the light-transmitting cover plate 110 from the side surface of the wafer 120 away from the wafer 120. The first cutting member 140 can be a cutter wheel that cuts off the light-transmitting cover plate 110 above the electrode 122, so that the electrode 122 on the wafer 120 is exposed, facilitating the wire bonding of the electrode 122 in the subsequent process. It can be understood that the depth of the groove 111 is greater than or equal to 5 um, so that there is a sufficient safety distance between the cutting stop depth and the electrode 122, ensuring that the cutter wheel will not damage the electrode 122 on the wafer 120.

[0087] Specifically, the design of the cutting path on the light-transmitting cover plate 110 can be designed according to the cutting type and cutting width of the cutter wheel. For example, if the cutting width of the cutter is greater than the width of the groove bottom of the groove 111, the light-transmitting cover plate 110 between two adjacent mounting portions 112 can be cut off at one time. If the cutting width of the cutter is greater than the width of the groove bottom of the groove 111, the light-transmitting cover plate 110 between two adjacent mounting portions 112 can be cut off twice. After cutting, only the part of the light-transmitting cover plate 110 corresponding to the mounting portion 112 is left, which is a single light-transmitting patch 117. It can be easily understood that the projection of the light-transmitting patch 117 on the wafer 120 can completely cover the light-emitting area 121. That is, the width or diameter of the light-transmitting patch 117 is greater than or equal to the width or diameter of the light-emitting area 121. The edge of the projection of the light-transmitting patch 117 on the wafer 120 falls between the electrode 122 and the light-emitting area 121, which provides sufficient operation space for the wire bonding of the electrode 122.

[0088] Step S6, the wafer 120 is cut to form a single chip.

[0089] Please refer to Figure 13 The second cutting member 150 is used to cut the wafer 120 to form a single independent chip, including but not limited to cutter cutting, laser cutting or hidden cutting.

[0090] Step S7, the chip is attached to the substrate 160. Please refer to Figure 14 The substrate 160 is provided with a pad 161, and each chip is attached to the substrate 160. The electrode 122 on the chip and the pad 161 on the substrate 160 are connected by a metal wire 162, realizing the electrical connection between the chip and the substrate 160, and forming a packaging structure.

[0091] The embodiment of the present application also provides a packaging structure made by the wafer-level packaging method of the OLED chip. The packaging structure comprises a chip, a light-transmitting patch 117 and a substrate 160. The chip is provided with a light-emitting area 121 and an electrode 122 spaced apart from the light-emitting area 121. The light-transmitting patch 117 is bonded to the light-emitting area 121 by a light-transmitting adhesive 130, and the electrode 122 is electrically connected to the substrate 160.

[0092] In summary, the wafer-level packaging method and packaging structure of the OLED chip provided by the embodiments of the present application have the following beneficial effects, including:

[0093] The light-transmitting cover plate 110 with a size comparable to that of the wafer 120 is bonded on the wafer 120 at one time, and then cut and separated into single light-transmitting patches 117 after the bonding is completed. This full-process wafer-level packaging process replaces the traditional single-chip packaging, greatly improving the packaging efficiency and reducing the cost. The wafer 120 level bonding process is used to pre-press, and then to press in a vacuum environment with heating and pressurization, which can effectively reduce the bubbles in the light-transmitting adhesive 130, ensure the uniformity of the adhesive thickness after pressing, and improve the light-emitting quality and packaging yield. The wafer-level pressing method can effectively control the amount and thickness of the light-transmitting adhesive 130, thereby improving the uniformity of the pressing. The vacuum environment, temperature and high pressure are used in the process to effectively expel the bubbles in the adhesive, which can improve the light-emitting quality of the OLED from multiple aspects. Before the bonding process, the groove 111 is formed on the light-transmitting cover plate 110, and the overflowed light-transmitting adhesive 130 can flow into the groove 111 during the bonding process, preventing the overflowed adhesive 131 from contaminating the electrode 122. Moreover, the bubbles in the adhesive can also be discharged into the groove 111, reducing the residual gas. The groove 111 structure is removed by cutting in the subsequent process, which can release the gas remaining in the groove 111, and expose the electrode 122, facilitating the subsequent wire bonding operation. The wafer-level packaging method of the OLED chip provided by the embodiments of the present application is beneficial to improve the packaging efficiency and packaging yield. Of course, this method is not only suitable for the wafer-level packaging of the OLED chip, but also suitable for the packaging of other chips with similar structures.

[0094] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent replacements for part or all of the technical features; any modification, equivalent replacement, improvement, etc. should be included in the protection scope of the present application.

Claims

1. A wafer level packaging method of an OLED chip, characterized by, The application relates to an OLED chip wafer-level packaging method. The method comprises the following steps: Providing a light-transmitting cover plate and a wafer respectively; wherein the wafer is provided with a plurality of light-emitting areas, and an electrode is arranged on the outer periphery of the light-emitting area; and a preset interval is arranged between the electrode and the light-emitting area; A plurality of grooves are formed on one side of the light-transmitting cover plate, and the depth of the grooves is smaller than the thickness of the light-transmitting cover plate; and a mounting part is formed between the grooves; A drainage groove is formed on the side wall of the groove; The wafer and the light-transmitting cover plate are bonded; wherein the light-emitting area corresponds to the mounting part one by one and is pressed together; The light-transmitting cover plate is cut along the edge of the mounting part, and the groove structure is removed, so that a wafer with a light-transmitting patch is formed; and the projection of the light-transmitting patch on the wafer does not overlap with the electrode; 2.The OLED chip wafer level packaging method of claim 1, wherein, The wafer is cut to form a single chip. The step of bonding the wafer and the light-transmitting cover plate comprises the following steps: A light-transmitting glue is formed on the light-emitting area of the wafer and / or the mounting part; 3. The wafer level packaging method of OLED chips according to claim 2, wherein, The wafer and the light-transmitting cover plate are pressed together; wherein the wafer is arranged on the upper side, and the light-transmitting cover plate is arranged on the lower side. The step of pressing the wafer and the light-transmitting cover plate comprises the following steps: The wafer and the light-transmitting cover plate are pre-pressed under normal temperature and pressure; 4. The wafer level packaging method of OLED chips according to claim 3, wherein, The wafer and the light-transmitting cover plate are pressed together under vacuum environment and under the condition of heating and pressurization. The step of pressing the wafer and the light-transmitting cover plate under vacuum environment and under the condition of heating and pressurization comprises the following steps: The wafer and the light-transmitting cover plate are pressed together under the condition of a first temperature and a first pressure for a first preset time, and are kept for a second preset time; The wafer and the light-transmitting cover plate are pressed together under the condition of a second temperature and a second pressure for a third preset time, and are kept for a fourth preset time; 5. The wafer level packaging method of OLED chips according to claim 1, wherein, The second temperature is greater than the first temperature; and the second pressure is greater than the first pressure. In the step of forming a plurality of grooves on one side of the light-transmitting cover plate, the grooves are formed by adopting a sandblasting or etching mode; 6. The wafer level packaging method of OLED chips according to claim 2, wherein, If the sandblasting mode is adopted, the step comprises at least two sandblasting processes; wherein the first sandblasting forms the grooves, and the second sandblasting polishes and corrects the groove wall; wherein the correction comprises correcting the inclination angle of the groove wall and the depth of the groove. The step of forming a light-transmitting glue on the light-emitting area of the wafer and / or the mounting part comprises the following steps: A glue-containing groove is formed on the mounting part; 7. The wafer level packaging method of OLED chips according to claim 6, wherein, The light-transmitting glue is formed on the mounting part. After the step of forming the glue-containing groove on the mounting part, the following step is further included:

8. The wafer level packaging method of OLED chips according to any one of claims 1 to 7, wherein, An overflow port is arranged on the groove wall of the glue-containing groove; and the overflow port communicates the glue-containing groove and the groove. In the step of forming a plurality of grooves on one side of the light-transmitting cover plate, the following step is further included:

9. A package structure, characterized by, A positioning mark part is formed on the side of the light-transmitting cover plate provided with the grooves. The OLED chip wafer-level packaging method is made by adopting any one of the OLED chip wafer-level packaging methods in claims 1 to 8.

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