JP2006130747A - Copper clad laminated sheet for cof and carrier tape for cof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper clad laminated sheet for COF which enables the formation of a fine pattern circuit and can prevent the sinking of a conductor at the eutectic time of Au-Sn into a polyimide layer. <P>SOLUTION: In the copper clad laminated sheet wherein the polyimide layer is provided on a copper foil, the polyimide layer has a thickness of 5-20 μm and is obtained by coating the copper foil with a polyimide in a solution state and drying and curing the coated copper foil. The polyimide layer shows non-thermoplastic characteristics at 350°C while the copper foil has a thickness of 5-50 μm and a surface roughness of 0.5-1.5 μm and has a metal treatment layer treated with at least one kind of a metal selected from Mo, Co, Ni and Zn, a chromate treatment layer and a silane coupling agent treatment layer. The 180° peel strength at the normal temperature between copper and the polyimide of the copper clad laminated sheet is 0.6 kN/m or above and a carrier tape for COF is obtained by processing the copper clad laminated sheet. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a copper clad laminate for COF (Chip on Film) and a carrier tape for COF obtained by processing the same.

  COF is a composite part in which a semiconductor IC is mounted on a film-like wiring board. In many cases, COF is used in connection with larger rigid wiring boards and display boards. And a film-like wiring board is made from the copper clad laminated board which laminated | stacked organic polymer films, such as a polyimide, and copper foil.

  A film-like wiring board is obtained by laminating a photosensitive resin layer on the copper foil surface of a copper-clad laminate, performing exposure corresponding to the desired wiring pattern, photocuring the photosensitive resin of the required part, and developing it. After removing the photosensitive resin in the unexposed portion, the coated copper layer of the substrate not covered with the cured resist is removed by etching, or the plating metal is deposited on the portion not covered with the cured resist by plating. Finally, a method is adopted in which the cured resist is removed by peeling to obtain a wiring board having a desired conductor pattern. As a method of laminating the photosensitive resin, there are a method of applying and drying a liquid resist and a method of laminating a photosensitive resin film.

  As a copper clad laminate for COF, a polyimide copper clad laminate obtained mainly by sputtering copper on a polyimide resin film has been used. In the case of the sputtering method, the yield is likely to deteriorate due to the pinhole of the metal layer, and therefore, a polyimide copper clad laminate having no pinhole is desired. As a copper clad laminated board without a pinhole, there exist what laminated | stacked the rolled copper foil, the electrolytic copper foil, and the polyimide. This laminate is obtained by laminating polyimide on a copper foil by casting or laminating methods, but there is also one in which a thermoplastic polyimide layer is formed on a metal foil in order to improve adhesive strength and the like.

  On the other hand, for chip mounting, there are methods for mounting at low temperatures such as ACF, NCP, and ultrasonic bonding, and methods for mounting at high temperatures of 300 ° C or higher such as Au-Au bonding and Au-Sn bonding. Au-Au junctions and Au-Sn junctions are often used from the viewpoint of mounting method and chip / wiring connection reliability.

JP 2004-207670 A JP 2004-153194 A JP 2004-128337 A JP 2004-31685 A JP 2001-315256 A Japanese Patent Laid-Open No. 2003-71984 JP 2003-23046 A

  Patent Document 1 discloses an example of a flexible printed wiring board for COF, in which a release agent layer such as a silane compound or silica sol is provided on the surface of the insulating layer opposite to the side on which the semiconductor chip is mounted. Are listed. Patent Document 2 describes a method of manufacturing a wiring board for COF, which includes a step of forming a release agent layer on an insulating layer after a photolithography step of patterning. In addition, it is described that the insulating layer is formed by a thermoplastic resin layer and an insulating film obtained by applying or thermocompression bonding a polyimide precursor resin solution to the conductor layer. It is also described that it is formed of a thermosetting resin layer and an insulating film.

  Patent Document 3 discloses a method for manufacturing a COF, which includes a resin coating process in which an insulating resin is applied to the surface of an insulating tape, and a semiconductor in which a semiconductor element is pressed from above the insulating resin and pressed onto a wiring pattern. A method is described that includes an element pressing process and a resin curing process in which an insulating resin is cured and a semiconductor element is fixed on a wiring pattern in an electrically connected state by pressing. Patent Document 4 discloses a method for manufacturing a COF film carrier tape, in which a reinforcing film is pasted on the opposite side of the insulating layer from the conductive layer and thermocompression bonded, and sprocket holes are formed in regions on both sides in the width direction. Forming a wiring pattern by forming a resist pattern on the conductive layer and etching, and forming a dummy wiring around a plurality of sprocket holes; and a step of performing thermocompression bonding between the reinforcing film and the insulating layer again. A method comprising the steps is described.

  Patent Document 5 discloses a flexible metal foil-clad laminate used for HDD, COF, and the like, which includes a metal foil, a thermoplastic polyimide layer, and a heat-resistant base film, and has a thermoplastic polyimide layer of 150 to 300. A thermoplastic polyimide film having a glass transition temperature of 1 ° C. or less and a water absorption of 1% or less, and a heat resistant base film having a glass transition temperature of 350 ° C. or more and a water absorption of 2% or less, respectively. The ones used are listed. Patent Document 6 discloses a polyimide copper-clad laminate in which a thermoplastic polyimide layer is formed on at least one surface of a non-thermoplastic polyimide layer, and a copper foil is laminated on the surface of the thermoplastic polyimide layer, and bonded to the thermoplastic polyimide. The polyimide copper clad laminated board whose thickness of the copper foil to be performed is 5 micrometers or less is described, and it describes that this is used for COF etc. Patent Document 7 describes a copper clad laminate for COF that is characterized by copper foil.

  In general, in the case of a polyimide laminate obtained by sputtering, a thermoplastic resin layer is not required, so that the phenomenon that metal wiring sinks into the polyimide layer does not occur when a chip is mounted at 300 ° C. or higher. There is a problem. When a polyimide layer is applied to a copper foil by lamination or pressure bonding, it is generally necessary to use a thermoplastic polyimide in order to increase the adhesion between the copper foil and the polyimide layer. is there. In particular, in the case of flip chip mounting using Au—Sn eutectic in the COF manufacturing process, since it is exposed to high temperature and high pressure, there has been a problem that thermal deformation occurs and the conductor sinks into the polyimide layer. Therefore, when a laminated sheet is produced by applying a polyimide resin or a precursor solution thereof using a coating method (also called a casting method), a copper foil is roughened to exert an anchor effect, and a thermoplastic polyimide is used. There has also been proposed a method for increasing the adhesive strength. However, this method has a problem in that the COF material is required to form a fine pattern circuit, but this is obstructed.

  An object of the present invention is to provide a copper clad laminate for COF that can form a circuit with a fine pattern and prevent the conductor from sinking into the polyimide layer during Au-Sn eutectic.

  The present invention is a copper clad laminate in which a polyimide layer is provided on a copper foil, and the polyimide layer is obtained by coating, drying and curing in a solution state on a copper foil, and is not heated at 350 ° C. It exhibits thermoplastic properties, and the surface roughness (Rz) of the polyimide laminate surface of the copper foil is in the range of 0.5 to 1.5 μm, and the 180 ° peel strength at room temperature between copper and polyimide is 0.6 kN / m or more. It is a copper clad laminate for COF characterized by being. The present invention also provides a carrier tape for COF obtained by processing the copper clad laminate for COF.

  Here, the fact that the polyimide layer is a single layer facilitates the production of a copper-clad laminate for COF. The copper foil is a non-roughened electrolytic copper foil, and the surface of the copper foil on the polyimide lamination side is treated with one or more metals selected from the group consisting of molybdenum, cobalt, nickel, and zinc. And having a chromate treatment layer and a silane coupling agent treatment layer is advantageous in order to increase the adhesive strength between the polyimide layer and the copper foil. And that the said metal treatment layer is an alloy layer which essentially requires zinc and nickel gives higher adhesive strength. Furthermore, when the thickness of the copper foil is in the range of 5 to 20 μm and the thickness of the polyimide layer is in the range of 5 to 50 μm, the usability as a carrier tape for COF is improved.

The present invention will be further described below.
The copper clad laminate for COF comprises a copper foil and a polyimide layer, and the copper foil may be on one side or both sides.

  The polyimide layer can be composed of a single layer or a plurality of layers, but if it is a single layer, its production is easy. When it consists of multiple layers, the structure which has the thin polyimide layer for raising the adhesive strength with copper foil on the adhesive surface side, and has the thick polyimide layer which shows high elasticity at high temperature on the surface side is preferable. The thickness ratio in this case is preferably in the range of 1: 2 to 1: 100. The polyimide layer exhibits non-thermoplastic properties at 350 ° C., preferably 400 ° C. In addition, when a polyimide layer consists of multiple layers, all the polyimide layers show the said characteristic. Here, the non-thermoplastic characteristics mean those having a storage elastic modulus of 0.5 GPa or more. If the storage elastic modulus is too high, a tendency of lowering the adhesiveness is seen, so that the one showing 3.0 GPa or less under the above conditions is desirable. Hereinafter, the polyimide (layer) having non-thermoplastic properties used in the present invention is also referred to as non-thermoplastic polyimide (layer) or simply polyimide (layer).

  The copper clad laminate for COF of the present invention is produced by applying a polyimide or polyimide precursor solution onto a copper foil, drying and curing to form a polyimide layer. The laminated board which has copper foil on both surfaces is manufactured by thermocompression-bonding copper foil (it may have a polyimide layer) to the surface of this polyimide layer.

  The non-thermoplastic polyimide forming the non-thermoplastic polyimide layer is not particularly limited, but a polyimide synthesized from a specific diamine and a specific tetracarboxylic dianhydride can be preferably used. Such diamines include o-phenylenediamine, p-phenylenediamine, m-phenylenediamine, 4,4'-diaminophenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diamino. -Biphenyl, 4,4'-diamino-2,2'-dimethylbiphenyl, 2,2-bis [4- (4-aminophenoxy) phenyl) propane, may have a substituent such as an alkyl group or an alkoxy group Good 4,4′-diamino-benzanilide and the like can be mentioned. These may be used alone or in combination of two or more. Further, although it can be used in combination with other diamines, the amount of the diamine component used is preferably 70 mol% or more.

  As such specific tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic acid Etc. These may be used alone or in combination of two or more. Further, although it can be used in combination with other tetracarboxylic dianhydrides, the amount of the specific tetracarboxylic dianhydride used is preferably 70 mol% or more.

  Furthermore, as the non-thermoplastic polyimide for forming the non-thermoplastic polyimide layer, a polyimide solution that is an intermediate of a commercially available non-thermoplastic polyimide film or a precursor solution thereof can be used. For example, Upilex (registered trademark) S, SGA, SN of Ube Industries, Ltd., Kapton (registered trademark) H, V, EN of Toray DuPont Co., Ltd., Apical (registered trademark) AH, NPI of Kaneka Corporation And intermediates such as HP.

  The thickness of the polyimide layer is not particularly limited, but 2 to 100 μm, preferably 5 to 50 μm is suitable.

  The copper foil used in the present invention is made of copper or a copper alloy containing 90% or more of copper, and the thickness thereof is not particularly limited, but 3 to 30 μm, preferably 5 to 20 μm is suitable. The copper foil may be an electrolytic copper foil or a rolled copper foil, but an electrolytic copper foil is preferably used. And this copper foil is not subjected to roughening treatment.

  The surface of the copper foil (referring to the surface in contact with the polyimide layer) is preferably subjected to a surface treatment in order to improve the adhesion with the polyimide layer. This surface treatment is preferably performed by sequentially providing a metal treatment layer, a chromate treatment layer and a silane coupling agent treatment layer on the surface of the copper foil.

In the method of providing the metal treatment layer, at least one metal selected from Mo, Co, Ni, and Zn, preferably a metal essentially containing both Zn and Ni, is attached to the surface of the copper foil. The coating weight, 1~50μg / cm ² as a metal, preferably 5-50 [mu] g / cm ² approximately. When both Zn and Ni are essential, Zn is preferably 1 to 5 μg / cm ² , Ni is 1 to 15 μg / cm ² , and the Ni / (Ni + Zn) ratio is preferably 0.70 or more. As a method for attaching the metal, a known method such as an electric or chemical plating method, a vacuum or a chemical vapor deposition method can be used.

  As a method for providing the chromate treatment layer, a known method such as cathodic treatment in which a copper foil provided with a metal treatment layer is immersed in a sodium dichromate solution and an electric current is passed can be used. A method for providing a silane coupling agent treatment layer is, for example, applying a silane coupling agent-containing solution such as 3-gridoxypropyltrimethoxysilane to a copper foil provided with a chromate treatment layer by a spray method or the like, and drying the solution. Known methods can be used.

  The surface of the copper foil used in the present invention (when surface-treated means the surface after the surface treatment) has a roughness (Rz) in the range of 0.5 to 1.5 μm. If the surface roughness (Rz) is smaller than this range, there is a problem that good adhesive strength cannot be obtained. If the surface roughness (Rz) is large, problems such as difficulty in forming fine wiring are likely to occur.

  The copper clad laminate for COF of the present invention can be produced by a method of applying a non-thermoplastic polyimide or precursor solution (hereinafter also referred to as varnish) to the copper foil surface, and drying and curing. As a method for applying the varnish, known methods such as a die coater, a comma coater, a roll coater, a gravure coater, a curtain coater, and a spray coater can be employed. In this case, it can be applied in multiple layers if necessary. As a method for drying and curing the applied varnish, a normal heating and drying furnace can be used. As the atmosphere of the drying furnace, air, inert gas (nitrogen, argon) or the like can be used. As the drying and curing temperature, a temperature range of about 60 to 400 ° C. is preferably used. Curing is performed until the polyimide precursor becomes polyimide. In addition, when it is necessary to make copper foil thickness thin, a part of copper foil is removed by uniform thickness by an etching process etc., and copper foil thickness is made into predetermined thickness.

  The copper-clad laminate for COF of the present invention thus obtained needs to have an adhesive strength between the copper-polyimide layers of 0.6 kN / m or more at room temperature and 180 ° peel strength. A preferred peel strength range is 0.8 to 2.0 kN / m. Such peel strength can be obtained by selecting an appropriate polyimide from the polyimides as described above, or by selecting an appropriate copper foil or processing conditions from the surface treatment conditions of the copper foil or copper foil. Here, the 180 ° peel strength is specifically measured under the conditions described in the examples.

  As a method for producing a film carrier tape for COF from a copper clad laminate for COF, a known method can be appropriately selected and used. For example, cut a copper-clad laminate for COF into a film of a predetermined width, and after providing sprockets on both sides of the film, provide a photosensitive resin layer on the copper foil surface side, and pass through a mask that provides a predetermined circuit It is exposed and then etched to remove either unexposed or exposed portions. Next, there is a method of forming a circuit pattern by etching the exposed copper foil using the remaining resin layer as a resist, and then removing the resist to obtain a COF film carrier tape.

  According to the present invention, it is possible to provide a copper-clad laminate for COF that has no pinholes and has little wiring displacement even when chip-mounted by Au-Au bonding or Au-Sn bonding. If necessary, a copper clad laminate for COF that can be filled with underfill can be provided.

  FIG. 1 is a conceptual diagram showing an example in which an IC chip is mounted on a COF film carrier tape. A circuit in which a gold-plated bump 2 of an IC chip 1 is formed on a polyimide layer 3 of a COF film carrier tape. 4 shows a state in which the copper foil of the copper clad laminate for COF is obtained by circuit processing and may be tin-plated. At this time, since the thermocompression bonding is performed at a high temperature of about 350 to 400 ° C., the thickness of the polyimide layer 3 in the crimping portion sinks from the initial thickness T1 to T2. It is desired to reduce this thickness difference T1-T2 as much as possible.

Hereinafter, the present invention will be described in more detail with reference to examples.
Abbreviations used in the examples are as follows.
PMDA: pyromellitic anhydride
BPDA: 3,3 ', 4,4'-biphenyltetracarboxylic acid
m-TB: 4,4'-Diamino-2,2'-dimethylbiphenyl
BAPP: 2,2-bis [4- (4-aminophenoxy) phenyl] propane
DAPE: 4,4'-diaminodiphenyl ether
MABA: 4,4'-diamino-2'-dimethoxy-benzanilide
DMAc: Dimethylacetamide

Synthesis example 1
The DMAc425g, the m-TB21.78g a (102.63 × 10 ^-3 mol) and DAPE13.70g (68.42 × 10 ^-3 mol) was dissolved with stirring in a separable flask 1L. Then on and ^{PMDA29.55g (135.49 × 10 -3 mol)} BPDA9.96g a (33.87 × 10 ^-3 mol) in portions to this solution, and the polymerization reaction, the polyimide precursor solution A high viscosity Obtained.

Synthesis example 2
MABA6651.3g (25.85mol) and DAPE3450.9g (17.23mol) were dissolved in 110.5kg of DMAc with stirring in a 130L stainless steel container. Next, PMDA9266.2g (42.48mol) was added little by little to this solution, and a polymerization reaction was performed to obtain a highly viscous polyimide precursor solution B.

Synthesis example 3
After dissolving BAPP1294.43 g (3.153 mol) in DMAc17386 g, PMDA708.49 g (3.248 mol) was added to this solution and a polymerization reaction was carried out to obtain a highly viscous polyimide precursor solution C.

  The polyimide precursor solution obtained in each synthesis example was bar-coated on a heat-resistant glass plate so that the film thickness after imide conversion was 40 μm, and dried at 130 ° C. for 5 minutes. Then, it was put into a vacuum thermostat, subjected to heat treatment at 200 ° C. for 30 min, 300 ° C. for 30 min, and 350 ° C. for 30 min, and peeled off from the glass plate to obtain a polyimide film having a thickness of 40 μm. Tg was measured by differential scanning calorimetry analysis (DSC) and thermomechanical analysis (TMA) of the obtained polyimide film, and viscoelasticity measurement was performed by dynamic mechanical analysis (Dynamic Mechanical Analysis).

Polyimide A obtained from the polyimide precursor solution A obtained in Synthesis Example 1 was a non-thermoplastic polyimide having no Tg observed and a storage elastic modulus at 350 ° C. of 1 GPa.
Polyimide B obtained from the polyimide precursor solution B obtained in Synthesis Example 2 was a non-thermoplastic polyimide having no Tg observed and a storage elastic modulus at 350 ° C. of 1 GPa.
In the polyimide C obtained from the polyimide precursor solution C obtained in Synthesis Example 3, Tg was observed between 300 ° C. and 350 ° C., and the storage elastic modulus at 350 ° C. was a thermoplastic polyimide of 0.1 GPa.

Processing example 1
An unroughened electrolytic copper foil with an average thickness of 18 μm was prepared, and the oil component and the oxide film on the surface were removed with diluted sulfuric acid at 30 ° C. on the surface. Furthermore, a nickel-zinc alloy layer was electrolyzed on the copper foil surface using a plating solution composed of nickel sulfate, zinc pyrophosphate, and potassium pyrophosphate.

Processing example 2
An unroughened electrolytic copper foil with an average thickness of 18 μm was prepared, and the oil component and the oxide film on the surface were removed with diluted sulfuric acid at 30 ° C. on the surface. Furthermore, a cobalt-nickel-zinc alloy layer was electrolyzed on the copper foil surface using a plating solution composed of nickel sulfate, zinc pyrophosphate, potassium pyrophosphate, and cobalt sulfate.

Processing example 3
A roughened electrolytic copper foil with an average thickness of 18 μm was prepared, and the oil component and the oxide film on the surface were removed from the surface with dilute sulfuric acid at 30 ° C. Furthermore, a nickel-zinc alloy layer was electrolyzed on the copper foil surface using a plating solution composed of nickel sulfate, zinc pyrophosphate, and potassium pyrophosphate.

Processing example 4
Further, the copper foil formed with the metal treatment layer obtained in treatment examples 1 to 3 was washed with water and an electrolytic solution having an anhydrous sodium chromate dihydrate of 2 g / l, a pH value of 4 and a bath temperature of 30 ° C. was used. Then, an electrolytic chromate treatment layer was formed at a current density of 1 A / dm ² for 5 seconds.

Processing example 5
The three types of chromate-treated copper foils obtained in Treatment Example 4 were washed with water, immersed in a 0.1 wt% γ-glycidoxypropyltrimethoxysilane aqueous solution as a silane coupling agent, and then immediately dried at 80 ° C. Then, a silane coupling agent treatment layer was formed. Since the obtained surface-treated copper foil was obtained from three types of copper foils on which the metal-treated layers obtained in treatment examples 1 to 3 were formed, the surface-treated copper foils 1, 2, and 3 were sequentially named. .

  For surface-treated copper foils 1 to 3, the surface roughness Rz is determined based on the definition of ten-point average roughness in JIS B 0601-1994 “Definition and display of surface roughness”. Measurement was performed with a P-15 manufactured by Tencor at a measurement length of 0.8 mm, a measurement speed of 20 μm / second, and a load of 2 g. As a result, the Rz of the surface-treated copper foils 1 and 2 was 0.8 μm, and the Rz of the surface-treated copper foil 3 was 2.5 μm.

Example 1
The polyimide precursor solution A was bar-coated on the surface-treated copper foil 1 so that the film thickness after imide conversion was 40 μm. Thereafter, it was dried at 130 ° C. for 5 minutes. Thereafter, this was put into a vacuum thermostat and subjected to heat treatment at 200 ° C. for 30 min, 300 ° C. for 30 min, and 350 ° C. for 30 min to obtain a copper clad laminate having a polyimide layer thickness of 40 μm. The copper foil surface of this copper clad laminate was observed with an optical microscope, and pinholes of 5 μm or more and surface depressions due to the pinholes were measured. As a result, the number of pinholes and depressions (referred to as the number of pinholes, etc.) was 0 / cm ² .
This copper clad laminate was uniformly showered for 1 minute with an etching solution of sulfuric acid concentration 5.0g / l, hydrogen peroxide 50g / l, copper concentration 20g / l, conductor thickness 8.0μm, polyimide layer A copper clad laminate for COF having a thickness of 40 μm was obtained.

The copper foil of the copper clad laminate for COF was processed into a 1 mm wide circuit, and the 180 ° peel strength from the polyimide was measured. As a result, it was 1.0 kN / m. Furthermore, even after this circuit was processed in a hot air oven at 150 ° C. for 168 hours, it was 0.5 kN / m, confirming that it was practical.

Examples 2-3 and Comparative Examples 1-4
A copper clad laminate for COF was obtained in the same manner as in Example 1 except that the type of surface-treated copper foil and the type of polyimide precursor solution were as shown in Table 1. Table 1 shows the results of the same evaluation as in Example 1 for the obtained copper clad laminate for COF. In Table 1, the type of copper foil indicates the type of surface-treated copper foil, and the type of polyimide indicates the type of polyimide precursor solution. The peel strength before the heat treatment is shown before the peel strength, and the peel strength after the heat treatment at 150 ° C. for 168 hours is shown thereafter. In addition, the fine workability indicates the accuracy of 50 μm pitch processing. The amount of deformation indicates the amount tested by the method described later.

Comparative Example 5
Table 1 shows the results of evaluation similar to the above for a non-adhesive copper-clad laminate by a commercially available sputter plating method. The polyimide layer of this non-adhesive copper-clad laminate was immersed in a 70 ° C. aqueous solution consisting of 33.5 g of water, 33.5 g of potassium hydroxide, 11 g of ethylenediamine, and 22 g of ethylene glycol for 3 hours to obtain a conductor layer. The roughness Rz of the surface of the conductor layer that was the interface of was measured and found to be 0.8 μm.

Example 4
The three types of copper-clad laminates obtained in Examples 1 to 3 were slit into 35 mm widths, and then sprocket holes were formed by punching. Next, using a photolithography method, a negative photoresist is applied and dried, a photoresist layer is formed on the copper foil, exposed and developed through a 50 μm pitch COF photomask, and the photoresist layer is formed. Patterned. Subsequently, using the photoresist layer pattern as a mask, the copper foil layer was dissolved and removed with an aqueous ferric chloride solution to form a copper foil pattern. Further, the photoresist layer was removed with a basic aqueous solution. When the obtained conductor layer pattern was observed, a good film carrier tape free from short circuit, disconnection, peeling or the like was obtained. The obtained circuit was pickled with an aqueous sulfuric acid solution and then tin-plated with Tinposit LT-34 manufactured by Shipley Co., thereby obtaining a tin-plated film carrier tape.

  Thereafter, an IC having gold bumps was mounted on the inner lead portion of the film carrier tape. Mounting is done using flip chip bonder "TFC-2100" manufactured by Shibaura Mechatronics Co., Ltd., bonding head tool temperature is 400 ° C, stage temperature is 100 ° C, and bonding pressure is 20gf per bump. It was.

  Next, the cross section of the COF film carrier tape on which the IC was mounted was observed and measured as T1 (film thickness) −T2 (mounting part film thickness) = T3 (resin deformation amount due to mounting) shown in FIG. In this example, the deformation amount T3 was 1 μm, and the connection between the inner lead and the bump was good.

Conceptual diagram showing an example of mounting an IC chip on a film carrier tape for COF

Explanation of symbols

1: IC chip 1, 2: Bamboo, 3: Polyimide layer, 4: Circuit

Claims (6)

  A copper-clad laminate with a polyimide layer provided on a copper foil, the polyimide layer being obtained by applying, drying and curing in a solution state on a copper foil, and non-thermoplastic properties at 350 ° C In addition, the surface roughness (Rz) of the polyimide laminate surface of the copper foil is in the range of 0.5 to 1.5 μm, and the 180 ° peel strength between copper and polyimide at normal temperature is 0.6 kN / m or more. A copper clad laminate for COF.   The copper clad laminate for COF according to claim 1, wherein the polyimide layer is a single layer.   The copper foil is a non-roughened electrolytic copper foil, and the surface of the copper foil on the polyimide laminate side is treated with one or more metals selected from the group consisting of molybdenum, cobalt, nickel, and zinc; and The copper clad laminate for COF according to claim 1 or 2, further comprising a chromate treatment layer and a silane coupling agent treatment layer.   The copper-clad laminate for COF according to claim 3, wherein the metal treatment layer is an alloy layer in which zinc and nickel are essential.   The copper clad laminate for COF according to any one of claims 1 to 4, wherein the thickness of the copper foil is in the range of 5 to 20 µm and the thickness of the polyimide layer is in the range of 5 to 50 µm. A carrier tape for COF obtained by processing the copper clad laminate for COF according to claim 1.

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