Chip on Film Package

Abstract

The present disclosure relates to a heat dissipation film chip package in which heat is dissipated through the rear surface of a base film having a chip mounted on its front surface. When a heat dissipation layer is formed on the rear surface of the base film, the heat dissipation film chip package can ensure improved heat dissipation efficiency.

Description

Technical Field

[0001] Various embodiments of the present disclosure generally relate to chip on film packages (hereinafter referred to as "COF packages"), and more particularly to heat dissipating chip on film packages in which heat is dissipated through a rear surface of a base film having a chip mounted on its front surface. Background Art

[0002] Related technologies

[0003] Recently, display panels such as LCD panels and LED panels include driver integrated circuits.

[0004] The driver integrated circuit has a function of processing display data provided from the outside and providing an image signal corresponding to the display data to the display panel. The display panel can output a screen through the image signal from the driver integrated circuit.

[0005] Typically, a driver integrated circuit is manufactured as a COF package and mounted on a display panel.

[0006] The driver integrated circuit may generate heat in the process of processing display data and outputting image signals at high speed. If the heat is excessively accumulated in the driver integrated circuit, the accumulated heat may cause physical deformation or changes in electrical characteristics in the driver integrated circuit, thereby reducing the reliability of the driver integrated circuit.

[0007] In most cases, the COF package is manufactured to have a structure in which a thermal interface material is dispensed on the top of the package to dissipate heat from a mounted driver integrated circuit. In the case of the above structure, the heat of the driver integrated circuit can be discharged through the thermal interface material dispensed on the top.

[0008] However, in the COF of the above structure, the allocated thermal interface material is formed to have a considerable thickness. Due to the presence of the thermal interface material, the COF has an increased total thickness. Due to the increased thickness, the above conventional COF may interfere with mechanical components when mounted on a display panel.

[0009] Furthermore, due to the load of the thermal interface material dispensed, sagging may occur in the COF transferred for mounting, which may be a factor that degrades the performance of the manufacturing process.

[0010] In addition, applying and curing the dispensed thermal interface material can take considerable time. Therefore, dispensing the thermal interface material can be a factor that increases the overall COF manufacturing time.

[0011] In addition, in order for COF to effectively dissipate heat, thermal interface materials need to be dispensed over a large area. However, due to the characteristics of the dispensing process, it is difficult to apply thermal interface materials over a large area. Summary of the invention

[0012] Various embodiments are directed to disclosing a heat spreader chip on film package that can reduce manufacturing time, can achieve improved heat dissipation efficiency due to application of thermal interface material over a large area, and can reduce thickness and load burden of the thermal interface material.

[0013] In one embodiment, a chip package on heat dissipation film may include: a base film having a chip mounted in a mounting area on one surface of the base film, and the base film is formed with a wiring line; and a heat dissipation layer formed by screen printing a thermal interface material on an opposite surface of the base film corresponding to the mounting area.

[0014] In one embodiment, a chip package on heat dissipation film may include: a base film, which is configured in a strip shape and defines a mounting area in each of at least two areas separated along the length of the base film, in which the chip is mounted and wiring lines are formed; and a heat dissipation layer, which is formed by screen printing a thermal interface material in at least two heat dissipation areas corresponding to the at least two mounting areas on opposite surfaces of the base film.

[0015] According to an embodiment of the present disclosure, a heat dissipation chip on film package includes a heat dissipation layer formed by screen-printing a thermal interface material on a rear surface of a base film having a front surface on which a chip is mounted and on which wiring lines are formed.

[0016] The heat dissipation layer formed by screen printing can have a small thickness and a small load, and can be applied to a large area.

[0017] Therefore, in the chip-on-heat-dissipation-film package according to the embodiment of the present invention, since the heat dissipation layer is formed to a small thickness, the package does not interfere with mechanical parts when mounted on the display panel. In addition, since the heat dissipation layer has a small load, it is possible to prevent the package from sagging when it is transferred for mounting, and the time required for applying and curing the thermal interface material can be reduced. In addition, since the heat dissipation layer can be formed over a large area, improved heat dissipation efficiency can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a side view showing an example representation of a heat dissipation chip-on-film package according to an embodiment of the present disclosure.

[0019] Figure 2 is a top view showing an example representation of a base film.

[0020] Figure 3 is a top view showing an example representation of a mesh plate.

[0021] Figure 4 is a representation of an illustrative example that aids in explaining a screen printing method for forming a heat dissipation layer.

[0022] Figure 5 is a top view showing an exemplary representation of a heat dissipation layer formed on the rear surface of the base film.

[0023] Figure 6 is a top view showing another example representation of a heat dissipation layer formed on the rear surface of the base film.

[0024] Figure 7 is a top view showing still another example representation of the heat dissipation layer formed on the rear surface of the base film.

[0025] Figure 8 is a top view showing still another example representation of the heat dissipation layer formed on the rear surface of the base film. DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Terms used herein and in the claims should not be interpreted as limited to general or dictionary meanings, and should be interpreted as meanings and concepts corresponding to the technical aspects of the present disclosure.

[0027] The embodiments described herein and the configurations shown in the accompanying drawings are preferred embodiments of the present disclosure, but do not represent all technical features of the present disclosure. Therefore, various equivalent substitutions and modifications may be made when the present application is filed.

[0028] Reference Figure 1 , a heat dissipation chip on film package (hereinafter referred to as “heat dissipation COF package”) 10 according to an embodiment of the present disclosure includes a base film 20 and a heat dissipation layer 30 .

[0029] The chip 12 is mounted on the front surface of the base film 20 , and the heat dissipation layer 30 is formed on the rear surface of the base film 20 .

[0030] The chip 12 may be understood as a driver integrated circuit. The chip 12 includes input pads (not shown) for receiving display data and voltage from the outside and output pads (not shown) for outputting source signals and voltage to a display panel (not shown).

[0031] The input pad and the output pad may be arranged on opposite sides of the bottom surface of the chip 12, and bumps 14 are formed on the input pad and the output pad, respectively. The bumps 14 may be understood as welding terminals formed to electrically connect the input pad and the output pad to the ends of the wiring lines 24 to be described below.

[0032] The base film 20 includes a film 22 made of polyimide, a wiring line 24 formed on the front surface of the film 22 , and a solder resist 26 coated on the wiring line 24 .

[0033] The mounting area 20b for mounting the chip 12 (see Figure 2 ) may be disposed on the front surface of the film 22. When the chip 12 is mounted, the bumps 14 may be located within the mounting region 20b on the front surface of the film 22.

[0034] Wiring lines 24 are formed on the front surface of the film 22, each of which has a predetermined pattern for electrical connection between the chip 12 and the display panel. One end of the wiring line 24 extends into the mounting area 20b to contact the bump 14, and the opposite end of the wiring line 24 opposite to the one end of the wiring line 24 extends to the side of the film 22 to be electrically connected to the display panel. The wiring line 24 can be formed of a conductive material such as copper (Cu).

[0035] Through the above configuration of the wiring lines 24 , each bump 14 of the chip 12 can be electrically connected to one end of the corresponding wiring line 24 .

[0036] The solder resist 26 is formed outside the region where the chip 12 is mounted and is coated on the wiring line 24 and the film 22. The solder resist 26 may be coated so that one end and the opposite end of the wiring line 24 are exposed. The solder resist 26 configured as described above serves as a protective film that protects the wiring line 24 below.

[0037] Filling resin 16 may be formed on the side surface of chip 12 mounted on the front surface of base film 20. Filling resin 16 may be understood as being configured to prevent moisture from passing through a gap between the lower end of the side surface of chip 12 and solder resist 26 and to securely fix chip 12.

[0038] The heat dissipation layer 30 is formed on the rear surface of the base film 20. More specifically, the heat dissipation layer 30 is formed by screen-printing a thermal interface material on the rear surface of the base film 20.

[0039] The following will refer to Figures 2 to 4 A method of forming the heat dissipation layer 30 by screen printing is described.

[0040] Figure 2 A base film 20 is shown. Figure 2 The base film 20 may be understood as the film 22 in a state where the chip 12 is not mounted and the wiring line 24 and the solder resist 26 are not formed.

[0041] Figure 2 The base film 20 is shown in a tape shape before being cut into package units.

[0042] The tape-shaped base film 20 may have a mounting region 20b defined in at least two regions separated along the length of the base film 20. A location 20c for mounting the chip 12 may be defined in each mounting region 20b.

[0043] The strip-shaped base film 20 may be taken from a reel to manufacture the strip-shaped base film 20 , and the strip-shaped base film 20 has through holes 20 a formed in rows on both sides of the strip-shaped base film 20 for feeding.

[0044] Figure 3 A mesh plate 40 is shown. The mesh plate 40 has meshes 42 formed in a frame.

[0045] Each mesh 42 may be understood as a screen formed with fine through holes, through which the thermal interface material on the mesh plate 40 passes and is supplied downward.

[0046] The meshes 42 are also formed in at least two areas separated along the length of the mesh plate 40 and have positions corresponding to the mounting area 20 b of the base film 20 .

[0047] In order to form the heat dissipation layer 30 according to the embodiment of the present disclosure, as Figure 4 As shown, Figure 3 The mesh plate 40 may be arranged and aligned on the rear surface of the base film 20 having a mounting area 20b defined on the front surface thereof, such as Figure 2 shown.

[0048] When the mesh plate 40 is Figure 4 When arranged and aligned as shown, each mesh 42 of the mesh plate 40 is positioned toward the rear surface of the base film 20.

[0049] like Figure 4 As shown, after the mesh plate 40 is arranged and aligned, the thermal interface material 32 is supplied onto the mesh plate 40. The thermal interface material 32 may pass through the mesh 42. As the thermal interface material 32, various materials may be used, each of which has adhesion to the rear surface of the base film 20, has a heat dissipation function, can be supplied in a gel state, can be cured after being supplied, and maintains flexibility even after being cured.

[0050] The squeezer 50 is disposed on the mesh plate 40. The squeezer 50 may include a blade having elasticity and a width greater than the mesh 42 at its lower portion. The squeezer 50 may be configured to reciprocate in directions M1 and M2 while contacting the top surface of the mesh plate 40 and the top surface of the mesh 42.

[0051] The thermal interface material 32 supplied onto the mesh plate 40 moves downward through the mesh 42 by being pressed by the pressurizer 50 moving in one direction.

[0052] Thus, the thermal interface material 32 is printed on the rear surface of the base film 20 to have a planar pattern determined by the meshes 42 and a uniform thin thickness.

[0053] When Figure 4 When the thermal interface material 32 is screen-printed on the rear surface of the base film 20 in the method, the heat dissipation layer 30 is formed at each position where each mesh 42 is formed (ie, at each position on the rear surface of the base film 20 corresponding to each mounting area 20b).

[0054] pass Figure 4 The heat dissipation layer 30 formed by the method may be formed to have each of various patterns corresponding to the shape of the mesh 42 at each position.

[0055] For example, the mesh 42 is formed as follows Figure 3 In the case of the rectangular shape shown, the heat dissipation layer 30 may be formed to have a rectangular pattern at each position. That is, the heat dissipation layer 30 is formed on the rear surface of the strip-shaped base film 20 to have a rectangular pattern at each position corresponding to each of the at least two mounting areas 20b.

[0056] Typically, an alignment key 20d is formed on the rear surface of the base film 20 for achieving alignment during the manufacturing process. One or more alignment keys 20d may be formed on the rear surface of the base film 20 corresponding to each mounting region 20b.

[0057] Therefore, the heat dissipation layer 30 may be formed not to overlap with the above-mentioned alignment key 20 d at each position corresponding to each mounting region 20 b .

[0058] To this end, the heat dissipation layer 30 is formed to have a heat dissipation layer 30 at each position corresponding to each mounting area 20b. Figure 5 or Figure 6 Rectangular pattern shown.

[0059] Figure 5 The heat dissipation layer 30 is shown formed to have a rectangular pattern which does not overlap with the alignment key 20 d formed on the rear surface of the base film 20 and has a length shorter than that of the corresponding mounting region 20 b .

[0060] Figure 6 The heat dissipation layer 30 is shown formed to have a rectangular pattern that does not overlap the alignment key 20d formed on the rear surface of the base film 20 and has a width smaller than that of the corresponding mounting region 20b.

[0061] Figure 5 and Figure 6 The heat dissipation layer 30 in each of the figures is formed so as to be confined within the range of the mounting area 20b at each position.

[0062] like Figure 5 and Figure 6As shown, the heat dissipation layer 30 is formed to have a rectangular pattern at each position corresponding to each mounting area 20b. Thereafter, the strip-shaped base film 20 is cut for each mounting area 20b. Figure 1 A separate heat sink COF package 10 is shown.

[0063] like Figure 7 As shown, the heat dissipation layer 30 may be formed in a stripe-shaped pattern on the rear surface of the stripe-shaped base film 20 .

[0064] The stripe pattern may be understood as extending in the length direction to correspond to at least two mounting areas and having a predetermined width. The heat dissipation layer 30 having the stripe pattern does not overlap the alignment key 20d formed on the rear surface of the base film 20 and has a width smaller than the width of each of the at least two mounting areas 20b.

[0065] like Figure 7 As shown, the heat dissipation layer 30 is formed on the rear surface of the strip-shaped base film 20 to have a strip-shaped pattern. Thereafter, the base film 20 is cut for each mounting area 20b. Figure 1 A separate heat sink COF package 10 is shown.

[0066] The heat dissipation layer 30 may be Figure 8 The alignment key 20d is formed at each position corresponding to the mounting area 20b in such a manner as not to overlap with the alignment key 20d.

[0067] Figure 8 The heat dissipation layer 30 is formed to have a pattern corresponding to each of the at least two mounting regions 20 b , and each pattern is formed to expose the alignment key 20 d formed on the rear surface of the base film 20 .

[0068] In more detail, in the alignment key 20d, Figure 8 In the case where the mounting area 20b is located at two opposite corners, according to Figure 8 The heat dissipation layer 30 of the embodiment has a pattern in which the thermal interface material 32 is printed in the remaining area by excluding two small rectangular corner areas where the alignment key 20d is located from the rectangular area including the alignment key 20d.

[0069] and Figure 8 Unlike the embodiments, the alignment key 20d may be formed at various positions within the rectangular mounting area 20b, and correspondingly, the heat dissipation layer 30 implemented by the present disclosure may be modified into various patterns excluding the area where the alignment key 20d is located, thereby exposing the alignment key 20d.

[0070] Therefore, when the heat dissipation layer 30 is formed to have Figures 5 to 8When the pattern is shown, the embodiment of the present disclosure may provide the following advantage: a manufacturing process may be stably performed using the alignment key 20d.

[0071] As apparent from the above description, the heat dissipation COF package according to the embodiment of the present disclosure may provide an advantage in that heat dissipation may be reliably performed by including a heat dissipation layer formed by screen-printing a thermal interface material on the rear surface of a base film.

[0072] Furthermore, in the heat dissipation COF package according to the embodiment of the present disclosure, the heat dissipation layer can be formed to have a uniform thin thickness and a small load, and the heat dissipation layer can be formed over a desired large area by screen printing.

[0073] Therefore, the heat dissipation COF package according to the embodiment of the present disclosure will not interfere with mechanical components when installed on the display panel, can prevent sagging during transfer for installation, can reduce the time required for applying and curing the thermal interface material, and can achieve improved heat dissipation efficiency because a heat dissipation layer can be formed over a large area.

[0074] Although various embodiments have been described above, those skilled in the art will appreciate that the described embodiments are merely exemplary. Therefore, the disclosure described herein should not be limited based on the described embodiments.

Claims

1. A heat dissipation chip-on-film package, comprising: a base film configured in a tape shape, the base film having a chip mounted in a mounting area on one surface of the base film, and the base film having a wiring line formed thereon; as well as a heat dissipation layer formed by screen printing a thermal interface material on an opposite surface of the base film corresponding to the mounting area, wherein the base film has holes formed in rows on both sides of the base film, The alignment key is located in two opposite corners of the mounting area, and the heat dissipation layer has a pattern in which the thermal interface material is printed in a remaining area by excluding two small rectangular corner areas where the alignment key is located from a rectangular area including the alignment key.

2. A heat dissipation chip-on-film package, comprising: a base film configured in a strip shape and defining a mounting region in each of at least two regions separated along a length of the base film, in which a chip is mounted and in which a wiring line is formed; as well as a heat dissipation layer formed by screen printing a thermal interface material in at least two heat dissipation areas on opposite surfaces of the base film corresponding to at least two mounting areas, wherein the base film has holes formed in rows on both sides of the base film, The alignment key is located in two opposite corners of the mounting area, and the heat dissipation layer has a pattern in which the thermal interface material is printed in a remaining area by excluding two small rectangular corner areas where the alignment key is located from a rectangular area including the alignment key.

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