KR102448823B1 - Pre-coated COF manufacturing method and COF structure produced by the method - Google Patents

Abstract

The present invention relates to a pre-coated chip on film (COF) structure. A pre-coated COF structure and a manufacturing process of the COF structure are disclosed. In the above structure, a first adhesive is applied only on a wiring lead on a COF film. The conductive ball is fixed by B-stage curing of the first adhesive after transfer adhesion. Both the upper part of an area where the conductive ball is attached and the wiring lead is pressurized and filled with a second adhesive. The first adhesive and the second adhesive maintain the semi-cured state of a B-Stage.

Description

Pre-coated COF (Chip on film) manufacturing method and COF structure manufactured by the manufacturing method {Pre-coated COF manufacturing method and COF structure produced by the method}

The present invention relates to a method for manufacturing a pre-coated COF (Chip on Film) and a COF structure manufactured by the manufacturing method.

In the technology of bonding a semiconductor package to a substrate, a film-shaped ACF (An-isotropic Conductive Film) is applied as an adhesive by putting a filler (conductive ball; solder ball) in a resin such as epoxy so that the filler acts as an electrical connection terminal. Alternatively, there is a bonding technology that applies an ACP (An-isotropic Conductive Paste) of a paste type containing conductive balls to a gel-like resin. In addition, a film-shaped NCF (Non Conductive Film) or a paste-type NCP (Non Conductive Film) or paste-type NCP (Non Conductive Film) used for the purpose of improving bonding reliability by filling the space between the terminals like underfill between the external connection terminal of the semiconductor package and the substrate There is a bonding technology that forms a conductive paste). In the ACF or ACP, a conductive filler, that is, a conductive ball, serves to conduct electricity in a vertical direction between the semiconductor package and the substrate.

The process of bonding the COF to the display panel with the ACF adhesive is as shown in FIG. 11, preparing a display panel (P') having a pattern such as an ITO (Indium Tin Oxide) thin film, containing conductive balls, and protecting or The ACF supported by a cover film such as a release film is cut and aligned with the panel P', and the ACF is temporarily bonded to the panel P'. Then, the cover film is removed, for example, the COF made of polyimide (PI) with copper wiring (hereinafter, wiring or lead or wiring lead) formed on the lower surface is aligned and then thermocompression-bonded to the panel P'.

On the other hand, in the process of attaching the pre-coated COF to the panel P', as shown in FIG. 12, the conductive ball is fixed only on the wiring of the COF with the first adhesive and the second adhesive is the conductive ball is fixed. A display panel (P') on which an ITO thin film pattern is formed on a pre-coated COF in which an anisotropic conductive adhesive layer is formed in advance on the COF in a B-stage state and between the wires and between the wires. and a simpler process of aligning the two members with thermocompression bonding. That is, instead of forming an anisotropically conductive adhesive layer on the COF in advance, the process of temporarily bonding the ACF to the display panel is omitted.

In No. 10-2021-0047757, which was applied for a patent on April 13, 2021 as a manufacturing method of pre-coated COF, the applicant applied ACP (An- Isotropic Conductive Paste) Adhesive is applied first, and after temporary curing to the first B-stage state, NCP (Non-Conductive Paste), a B-stage epoxy for close contact that does not contain filler, is applied between the lead surface and between the leads. After secondary coating and adhesion, a process for making a B-stage cured epoxy was started.

The present invention is a further improvement of the above patent application.

In the present invention, the conductive ball is located only on the wiring lead and the rest of the space is filled with NCF or NCP in a semi-cured state, so that the overall physical properties of the COF are improved and a new pre-coated method that can replace all processes using the existing ACF. An object of the present invention is to provide a COF (Chip on Film) manufacturing method and a COF structure manufactured by the manufacturing method.

In order to achieve the above object, the present invention is a pre-coated COF (Chip on Film) structure, wherein the structure is formed by bonding and curing conductive balls through a first adhesive only on the wiring leads on the COF film. A second adhesive is applied and filled in both the upper part of the area to which the conductive ball is adhered and the wiring leads, and the second adhesive provides a pre-coated COF structure that maintains the semi-cured state of the B-Stage. .

The first adhesive is NCP (Non-Conductive Paste) on a gel that does not contain conductive balls, and the second adhesive is NCP (Non-Conductive Paste) or NCF (Non-Conductive Paste) that does not contain conductive balls. can

In addition, the present invention provides a manufacturing process of a pre-coated COF (Chip on Film) structure, the process comprising: preparing a COF film having wiring leads formed on its upper surface; coating the wiring leads by applying a first adhesive on a gel; transferring the conductive ball onto the first adhesive, provisionally curing (or curing to a B-stage state), and fixing the conductive ball; aligning with the COF film by preparing a second adhesive; and press-bonding the second adhesive by blanking and weak thermocompression bonding so as to cover the joint of the COF film to which the first adhesive is coated and the conductive ball is fixed, so that the second adhesive is also semi-cured (or to a B-stage state). curing) state, and allowing the second adhesive to closely fill the space between the wiring lead and the wiring lead, including the upper portion of the wiring lead to which the conductive ball is attached.

In the step of coating by applying the first adhesive on the gel on the wiring lead, after coating (or applying) the first adhesive to a certain thickness on the transfer tool, align and close it with the wiring lead of the COF film to attach it to the transfer tool. It may include a step of transferring the adhered adhesive onto the wiring to be transferred.
The wiring leads of COF, TCP (Tape Carrier Package), FPC (Flexible Printed Circuit) or PCB (Printed Circuit Board) having a pitch of 20-50um are formed on a resin substrate with a thickness of about 8-18um. The first adhesive transfer tool can be applied in various shapes, materials and devices, but it is important to design a transfer mechanism that makes parallel contact at the moment of close contact so that the adhesive is transferred only on the wiring and the adhesive does not stick between the wiring and the wiring. do.
Even when coating (or applying) the first adhesive to the transfer tool, it is important to coat the coated adhesive with a homogeneous thickness so that there is no clumping. It is important to select the adhesive viscosity and coating method.
In the present invention, good results were obtained in the case of manufacturing and applying a precision bar-shaped glass or metal having high horizontality, which will be described first.
A tool that uniformly coats (or applies) the first adhesive in gel to a thickness of several hundred nm to several um on the surface of the transfer tool is a quantitative dispensing device equipped with various shapes of syringes and dispensing tips or rolls. (roll) coating, ink stamping (ink stamping), such as a conventional gel (Gel) material or high-viscosity liquid material may be one of the thin film coating device. However, by applying the structure of the container and the discharge device that minimizes the exposure of the adhesive to the air, it is desirable to have a coating device structure that minimizes the deterioration of the adhesive or the change of the viscosity even for a long continuous operation.
The transfer tool is a quantitative dispensing device using a dispensing device connected to a syringe, or a needle or multi-daughter used for coating of uniform thickness and distribution, or a glass or metal bar or stamp ( Stamp) or a coating device using a roller, or a printing device including a screen mask.

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The conductive ball is a conductive powder material of several um or several tens of um in size, or an insulation layer coated powder material with a certain insulating film applied to the surface of the powder, or a non-conductive polymer, Teflon, silicone It may include a powder-shaped conductive ball coated with a metal film on a resin and a conductive ball having a non-conductive insulating film formed on the surface again.

In addition, the present invention provides a semiconductor device including the above pre-coated COF structure.

In addition, the present invention provides an electronic device including the above semiconductor device.

According to the present invention, productivity can be improved and costs can be reduced in a display panel manufacturing process. In other words, in the process of bonding COF to the display panel, the time and process of temporary bonding of ACF are omitted, thereby shortening the panel manufacturing time, increasing production per hour, and reducing investment costs when expanding new lines that cost tens or hundreds of billions of dollars. can do. It is beneficial to reduce the investment cost due to the improvement of panel assembly line productivity rather than the cost of manufacturing the pre-coated COF.

According to the present invention, bonding reliability due to low bonding resistance can be improved. That is, since the number of conductive balls disposed on the wiring can be dramatically increased, high reliability in junction resistance can be secured.
In the case of ACF, the conductive connection resistance can be reduced by increasing the number of conductive balls contained in the adhesive, but the risk of a short circuit between the wiring increases, which limits the content of the conductive balls and also limits the long-term reliability.
According to the present invention, it is possible to improve the straightness rate in the assembly process of connecting and bonding the COF to the display panel. In other words, in the case of ACF-applied panel and COF bonding, the conductive balls contained in ACF cause electrical short circuit (Electrical Bridging or Short) defects between wirings on the panel and between wirings on the COF. It cannot go straight and may be temporarily excluded, but in the case of pre-coated COF, since conductive balls are placed only on the wiring, the risk of short circuit between wiring is extremely reduced, resulting in reduction of short circuit defects, reduction of rework, improvement of straightness rate, and productivity. It is also improved.

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1 is a flow chart of the manufacturing process of the pre-coated COF of the present invention;
Figure 2 is a view showing the manufacturing process of the COF of the present invention to be easily understood;
3 is a photograph of observing the dispersion of conductive balls placed on and between wires after thermocompression bonding by applying commercial ACF to commercial COF of 28 μm pitch on transparent glass without electrodes;
4 is a conductive ball placed only on the wiring after thermocompression bonding the pre-coated COF made by applying the pre-coated manufacturing process of the present invention to the 28um pitch COF of FIG. 3 to the transparent glass without the electrode of FIG. A drawing of a photograph of the arrangement viewed from the transparent glass side;
5 is a graph showing an increase in contact resistance according to the content of conductive balls according to the reliability test time;
6 is a graph showing that the smaller the wiring pitch of the COF, the higher the rate of occurrence of an electrical short caused by the conductive ball.
7 is a photograph confirming that the conductive balls contained in the ACF are dispersed even between the wires and the wires when the commercial COF is bonded to the transparent glass with a commercial ACF adhesive and observed with a transmission microscope between the wires of the COF. drawing;
8 is a diagram showing the location of a conductive ball between the wiring and the wiring after thermocompression bonding the pre-coated COF manufactured by applying the pre-coated COF technology of the present invention to the commercial COF of FIG. 7 to transparent glass. A drawing of a photograph confirming that it is not;
9 is a view showing a process of applying a first adhesive; and
10 is a view of an actual photograph applied as one of the transfer tool shapes for application of the first adhesive;
11 is a view showing a process of bonding the ACF to the COF with an adhesive to the display panel; and
12 is a view showing a process of attaching the pre-coated COF to the panel (P').

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

The manufacturing process of the pre-coated COF of the present invention will be described.

1 is a flowchart illustrating a manufacturing process of a COF of the present invention, and FIG. 2 is a diagram illustrating the manufacturing process for easy understanding.

Referring to the two drawings, first, a COF film 1 having a conductive line 12 formed thereon is prepared (S10 and FIG. 2A). The COF film 1 having a thickness of several tens of um may be, for example, polyimide as a main component. The conductive line 12 may be a copper wire plated with tin or gold, but is not limited thereto.

Next, the first adhesive 20 on the gel is applied on the conductive line 12 and coated (S12 and FIG. 2B). The first adhesive 20 is preferably a B-stage epoxy resin that does not contain a conductive ball, and includes an insulating and bonding material commercially available under the name of NCP (Non Conductive Paste). The first adhesive 20 is not limited to an epoxy resin, and any single or composite resin material on a gel used as an adhesive that undergoes a complete curing process after semi-curing in the semiconductor package and mounting process may be used.

Next, the conductive ball 30 is transferred onto the first adhesive 20 (S14 and FIG. 2C). At this time, the conductive ball 30 is transferred and adhered to the first adhesive by the viscosity of the first adhesive on the surface of the transfer tool. ) and maintains a stably fixed state without being pushed aside in the process of applying the second adhesive (S16). By the above steps, the conductive ball 30 is present only in the upper portion of the conductive line 12 .

The conductive ball applied to the present invention is for electric conduction between the panel and the COF, and has a conductive powder shape of several um or several tens of um having conductivity, as well as a material having a certain insulating film applied to the conductive material (Insulation). Electrical connection of semiconductor packages and display panels, such as a powder-type conductive ball coated with a layer coated powder) or a non-conductive polymer, Teflon, silicone resin, etc. and a conductive ball with a non-conductive insulating film formed on the surface again It includes all conductive balls that are used for mounting work for current and play the role of anisotropic conductivity.

Next, prepare the second adhesive 40, the back of which is supported by the cover film 42, and align it with the COF film 1 that has been subjected to step S16 (S18 and FIG. 2D). The second adhesive 40 may be a B-stage epoxy resin, a phenol resin, or a composite resin in which a thermoplastic resin including a rubber material is mixed therein, and may be a different component from the first adhesive 20 , it does not contain conductive balls, so it has a B-stage curing characteristic among adhesives classified as normal NCF (Non Conductive Film) or NCP (Non Conductive Paste) applied to semiconductor packaging or SMT (Surface Mounting Technology) process. adhesives with
The process diagrams of FIGS. 1 and 2 described in the present invention show a process diagram of applying NCF with a cover film as the second adhesive, but when applying liquid NCP, it is generally known that only the application method needs to be changed. It can be applied to a material that is applied to a certain area with a certain width and thickness and maintains the B-stage state by temporary curing. However, in the present invention, it is preferable to punch and press-bond the NCF on the film rather than applying the NCP on the gel with the second adhesive, and it takes precedence when applying.

There are several reasons for prioritizing NCF, but the first is that, in the case of ACF applied to a fine pitch of several tens of um like recent COF, those with widths of 1.0, 1.2, and 1.5 mm are mainly used. In the case of alternative application, the method of forming and maintaining the width of the film is not easier than that of the film.

Second, although there are differences in the material properties of each material, NCF is applied to the panel by applying NCP on gel as a second adhesive to maintain it in a B-stage state. In the case of thermocompression bonding with the second adhesive, more bubbles may be generated.

Next, by blanking the second adhesive 40, heat and pressure are applied to the bonding portion of the COF film 1 on which the wiring leads are arranged, and press-bonding is applied (S20 and FIG. 2E). The second adhesive 40 fills the space between the conductive line 12 and the conductive line 12 including the conductive line 12 to which the conductive ball 30 is attached. When the second adhesive 40 is in the gel phase, it is applied to the junction of the COF in the pre-B-stage state and semi-cured to the B-stage state to complete the pre-coated COF. In the case of the ) phase, it is itself B-staged, and it is pressed and adhered to the junction of the COF to complete the commercialization of the pre-coated COF. A second adhesive with weak viscosity applied by these two methods is fully cured from B-stage to C-stage in a short time at high temperature when thermally compressed with a display panel will proceed with

Next, the cover film 42 is separated and removed from the product that has undergone step S20 (S22). Step S22 may be executed simultaneously with step S20.

As described above, in the present invention, the first adhesive (NCP) that does not contain conductive balls is applied only on the wiring leads, and the conductive balls are transferred and bonded only on this, and then temporarily cured (or B-) by thermal curing or UV irradiation. Temporary bonding by applying, semi-hardening, or weak heat between the wiring leads and the wiring leads, including the wiring leads to which conductive balls are fixed. The pre-coated COF preparation method is characterized by being brought to the state.

In the present invention, regardless of the shape of the conductive ball 30, the conductive ball 30 is not positioned between the conductive line 12 and the conductive line 12 because it is fixed only on the conductive line 12 of the COF. ), the electrical insulation is very good even if the insulating film coating or other insulating technology for maintaining the gap between the conductive balls 30 is not applied, and it is possible to manufacture and apply a conductive ball that is inexpensive compared to the manufacturing cost of the conventional insulating film coated conductive ball.

The present invention provides a way to mount a flip chip package on a PCB or FPCB board using ACF in addition to forming an anisotropic conductive junction on the package film wiring in advance after manufacturing a package such as COF, TCP, etc. for mounting the existing LDI (LCD Driver IC). When replacing the ACF and forming an anisotropic conductive adhesive layer so that conductive balls are placed only on the terminals of the board, the present technology can be applied. That is, the pre-coated COF of the present invention applies an anisotropic conductive conductive ball to semiconductor packages such as COF, TCP, FPCB IC, FC (Flip Chip) FPCB, and FC CSP (Chip Scale Package) to PCB, ITO (Indium Tin Oxide) In all processes of applying ACF or ACP in order to be electrically connected to a substrate such as glass, it can comprehensively replace the existing ACF, ACP coating, and coating processes, that is, a COF package with ITO Glass or Printed Circuit Board (PCB) ) When bonding to the substrate, ACP or ACF is applied to the lower connection terminal of the SMT-type semiconductor package and the bonding wiring part on the board, including the bonding method in which the conductive balls contained therein are energized only in an anisotropic manner by applying ACP or ACF adhesive. By applying and improving the method of making electrical connection only up and down anisotropy using the conductive balls contained therein, the conductive balls are arranged only on the lower terminal of the package, or the conductive balls are selectively placed only on the junction of the board for bonding, It can be applied and applied to most SMT (Surface Mounting Technology) type package mounting that conducts electricity.

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Since the pre-coated COF of the present invention is provided in a temporary bonding state, it can be combined with any semiconductor device or component of a package.

Table 1 below compares the physical properties of the COF package when the conventional ACF bonding method and the pre-coated COF of the present invention are applied. COF is the result of measurement and evaluation of 20um pitch FPC.

In Table 1, the physical properties of ACF reflect the published data for commercial ACF, and the mechanical and electrical property values for Pre-Coated COF, which is the present invention technology, are measured according to the measurement standards similar to methods known as commercially available methods for measuring properties of ACF. It is the measured value. Table 1 shows the measured level of the result, not the condition level for completing the result of this technology development.

characteristic item unit ACF Pre-coated COF Initial Shear Strength N/cm2 37 or more 45 or more Peel Strength kg/cm 1.0 1.2 initial contact resistance mΩ 500 or less 450 or less Electrical Insulation Characteristics Ω 10 ⁹ or more 10 ¹⁰ or more Applicable pitch um 25 or more 20 or more catch rate % 10 to 40 over 90

The first item, the initial shear strength, is the same as the technology applied to the pre-coated COF production on a certain area (25mmw x 12.5mml) of one PCB end by preparing two PCB boards with the size of 25mmw x 100mml x 0.7mmt. After applying the process, applying the first adhesive, conductive ball transfer, and applying the second adhesive, temporary curing, and thermocompression bonding with the end of another PCB, and then measuring the shear strength with a tensile strength tester. The applied standard is “KS M 3705:2020, General Test Method of Adhesive”.

In the case of the second item, Peel Strength, the pre-coated COF manufacturing process of the present invention is applied to the wiring joint of the FPC, and after applying the first adhesive and transferring the conductive ball, a second adhesive with a width of 1.2mm, a length of 40mm, and a thickness of 20um is applied. After temporary welding, prepare a sample that is thermocompressed on transparent glass under the compression condition of 290 degrees for 10 to 15 seconds, which is the main compression condition, and hold one side with a peel tester of Dage-4000 model to maintain a 90 degree angle. It is a value expressed by converting the tensile strength value pulled while making it into the peeling strength per length (Cm) of the width of the joint.

The initial contact resistance was measured by specially manufacturing a pattern in which one wire was split into two wires for measuring voltage and current characteristics for 4-point probing, and 20um pitch wires were applied to FPC and Glass respectively through photo processing and additive plating. After manufacturing with the process, our Pre-Coated COF process is applied to the FPC to apply and form the B-stage adhesive, and after thermocompression bonding with the glass, one wire of the FPC is compressed and energized with the wire of the lower glass and the conductive ball. It is a value obtained by performing a 4-pint probing test after connecting The electrical insulation value between two wires is measured.

The fourth item, the meaning of the application pitch of pre-coated COF, is that when the pre-coated COF process, which is the present invention technology, is applied and manufactured to FPC manufactured with a 20um pitch, and when it is thermocompressed with a glass pattern of 20um pitch, electrical and mechanical problems are eliminated. It means that good results were obtained without the need for a pitch.

The capture rate is the same as that of thermocompression bonding of commercial 30um pitch COF and transparent glass using commercial ACF. By applying the Pre-Coated COF technology of the present invention to 30um pitch COF, each sample that is thermocompression bonded to transparent glass is glass. Observed from the side, it is a value expressing the ratio of the number of conductive balls placed on the wiring to the number of conductive balls located in the space between the wiring in a certain area of 1500um ² including the gap between the wiring.

As shown in this result, it can be seen that in the pre-coated COF technology, the conductive balls are placed only on the wiring, so the catch rate of the conductive balls is significantly higher than in the commercial ACF.

3 is an observation from the transparent glass side of a commercial COF with a pitch of 28um, Line/Space = 10um/20um and a commercial ACF adhesive to the transparent glass. The number of conductive balls bonded on the wiring area of 1500um ² is 3- 4 were confirmed. The commercial ACF applied in this experiment has a width of 1.2mm and a thickness of 18um. The conductive balls contained in the ACF have an average diameter of 3um and are Ni/Au plated. known to be used.

In contrast, a photograph of a state viewed from the transparent glass side after applying the pre-coated COF manufacturing process of the present invention to the same COF and thermocompression bonding it to the transparent glass is shown in FIG. 4 . In the pre-coated COF before thermocompression bonding, the conductive ball is bonded only on the wiring, and the adhesive is applied on both the wiring and between the wirings.

If you observe the periphery of the wire where the COF pre-coated on the transparent glass is thermocompression bonded, it can be confirmed that a large number of conductive balls are placed only on the wire. The number of conductive balls joined to the wiring area of 1500um ² is 22~28, which shows the density of conductive balls 8 times higher than that of commercial ACF. The density of conductive balls can be adjusted in the COF manufacturing process. The transparent glass applied in the experiment is 0.7mm thick and has a thickness similar to the thickness of the display panel used in manufacturing LCD and OLED.

The second adhesive applied to the pre-coated COF had a film shape similar to that of ACF, and had the same width as ACF of 1.2 mm and a thickness of 20 μm, and a conductive ball was applied with a diameter of 3 μm. However, the inventors of the present inventors applied their own patented conductive ball that vacuum-deposited Ni on a 3um plastic core and plated Au on it. Compared to the Ni/Au electroless plating conductive ball applied to commercial ACF, It has very good adhesion with plastic powder and plastic core).
The thermocompression bonding conditions of the commercial ACF and the process of the present invention are the same, the setting temperature of the crimping tool is 290 degrees, and the thermocompression bonding time is 10 to 15 seconds. Despite the high density of conductive balls, the peel strength of the COF after thermocompression bonding was about 1 kg/Cm in the case of ACF bonding and 1.2 to 1.6 kg/Cm in the case of the present invention.

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Combining the above evaluation results, it can be confirmed that the pre-coated COF of the present invention is excellent in all aspects such as initial bonding strength, initial bonding resistance, application pitch, electrical insulation properties, and capture rate.

In particular, the difference in the capture rate is closely related to the initial contact resistance and reliability between the COF and the display panel, electrical short circuit, and the increase in the number of pixels of the display panel according to the narrow pitch, that is, the clarity of the screen.

5 shows that when the content of the conductive balls contained in the commercial ACF is small, the initial contact resistance is sharply increased compared to those with a high content of the conductive balls in the long-term reliability evaluation. Of course, there may be a way to lower the initial contact resistance and increase the reliability by increasing the content (%) of the conductive balls contained in the commercial ACF. There is a problem in that the risk of short circuit increases and the adhesive strength is weakened, so there is a limit in increasing the content.

In commercial ACF, if the content of conductive balls is increased, the adhesive content (volume specific gravity) decreases and the adhesive strength is weakened. Adhesive is closely adhered and filled, so it has the strength of not weakening the adhesive force.

6 shows that the smaller the wiring pitch of the COF, the higher the rate of occurrence of an electrical short between wires due to conductive balls. . That is, commercial ACF means that the risk of a short circuit remains because an insulating conductive ball is also located between the wiring and the wiring.

When applied to a display panel, the wiring pitch of COF is getting smaller as the number of pixels increases and density increases day by day, and this becomes one of the core display technologies. 5 and 6 show the limitations of the commercial ACF application technology in further reducing the current wiring pitch, whereas the Pre-Coated COF technology of the present invention arranges conductive balls only on the wiring. It can be seen that it will be more advantageous and effective for the COF application of

The filler content of ACF currently commercialized is around 10%, and the sample confirmed by the inventors after thermocompression bonding of commercial ACF bonding to glass showed a very low content within 5%. On the other hand, in the case of the pre-coated COF of the present invention, since almost all conductive balls are arranged in alignment with the line, the number (density) of the conductive balls disposed on the wiring is compared to the number in the commercial ACF in FIGS. 3 and 4 In the analysis results alone, it was found to be more than 8 times higher.

Therefore, through the graphs of FIGS. 5 and 6, the Pre-Coated COF applied with this developed technology can secure very high reliability not only in the initial contact resistance at a very low level compared to the commercial ACF applied bonding method, but also in the long-term reliability evaluation. sufficiently predictable.

7 and 8 are photos obtained under a microscope in transmission mode to observe conductive balls placed between wirings. It can be seen that this is dispersed. ACF is manufactured so that the conductive balls are uniformly dispersed throughout the film, so the same number of conductive balls are located between the wires as on the wires.

8 is an observation photograph after applying the pre-coated COF of the present invention to the same panel and thermocompression bonding, and it can be seen that almost no conductive balls are disposed between the wiring and the wiring.

Next, as a method of applying the first adhesive 20 in gel form on the conductive line 12, as shown in FIG. 9, the width and length of the metal or glass rod are processed according to the area to be applied After applying the first adhesive 20 to the tool 100, it is preferable to use a method of aligning it to the bonding portion of the COF film 1 and transferring it.

10 is an actual photo of the transfer tool 100 for application, including a lower second glass holder 102 and an upper first glass holder 104, for adhesive transfer to the first glass holder 104 A rod 106 is installed.

The above is an example of the transfer tool 100, and the first adhesive transfer tool has a high level of horizontality so that the adhesive is transferred only on the wiring with a thickness of about 8 to 12 μm, and the adhesive is not attached between the wiring and the wiring, that is, it is not transferred. A tool that is in the shape of a glass or metal rod and uniformly coats (or applies) the first adhesive on the surface to a thickness of several hundred nm to several um. It may be a quantitative discharge device, or it may be one of a thin film coating device of a conventional gel material or a high-viscosity liquid material such as roll coating and ink stamping. However, it is desirable to have a structure of a container and a discharge device that minimizes the exposure of the adhesive to the air, and a coating device structure that minimizes the deterioration of the adhesive or the change in viscosity even for a long continuous operation.

Although the preferred embodiment of the present invention has been described above, various changes and modifications are possible with respect to the present invention, and it is obvious that the scope of the present invention extends to the same or equivalent scope as the claims described below.

Claims (11)

A pre-coated COF (Chip on Film) structure, wherein the conductive ball is adhered and cured only on the wiring lead on the COF film through the first adhesive, and between the upper portion of the area to which the conductive ball is fixed and the wiring lead All of them are filled with a second adhesive, and the second adhesive maintains the semi-cured state of the B-Stage, pre-coated COF structure. The method of claim 1,
The first adhesive is NCP (Non-Conductive Paste) that does not contain conductive balls, and the second adhesive is NCP or NCF (Non-Conductive Film) that does not contain conductive balls, pre-coated COF structure. A process for manufacturing a pre-coated chip on film (COF) structure, the process comprising:
preparing a COF film on which wiring leads are formed;
coating the wiring leads by applying a first adhesive on a gel;
transferring, semi-curing, and fixing the conductive ball on the first adhesive;
aligning with the COF film by preparing a second adhesive; and
The second adhesive is blanked so that the second adhesive covers the junction with the substrate including the area where the first adhesive and conductive ball are applied and adhered to the electrical connection of the COF and the joint wiring and press-bonded while applying heat and pressure. A process comprising: maintaining a semi-cured state of the first adhesive and the second adhesive, and allowing the second adhesive to fill the space between the wiring lead and the wiring lead, including the upper part of the wiring lead to which the conductive ball is attached 4. The method of claim 3,
B-stage curing or semi-curing of the first and second adhesives is by heat or a process that includes semi-curing by UV irradiation when the adhesive material is a UV-reactive material. 4. The method of claim 3,
The step of coating by applying the first adhesive on the gel on the wiring lead comprises applying the first adhesive to the transfer tool and then aligning it with the wiring lead of the COF film and transferring the same. delete 6. The method of claim 5,
The first adhesive transfer tool is in the shape of a hard glass or metal rod, and the tool that coats the first adhesive on the surface is a quantitative dispensing device equipped with various shapes of syringes and dispensing tips, or roll coating, ink A process that applies one of the thin film coating devices of common gel materials or high-viscosity liquid materials, such as ink stamping. The method of claim 1,
The conductive ball is in the shape of a conductive fine powder of several um or several tens of um, or a material in which a certain insulating film is applied on the conductive fine powder material (Insulation Layer Coated Powder), or in the form of a powder coated with a metal film on a non-conductive polymer, Teflon, or silicone resin A pre-coated COF structure comprising a conductive ball of or an insulating film applied thereon again. A semiconductor device comprising the precoated COF structure of claim 1 . An electronic device comprising the semiconductor device of claim 8 . A semiconductor package manufacturing process comprising the manufacturing process of the pre-coated COF structure of claim 3 .

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