WO2004088738A1 - Laminate - Google Patents

Abstract

A laminate comprising a conductive layer and an insulating layer and having an excellent electron migration resistance. The adhesion between the conductive and insulating layers is strong. When a driver IC chip is mounted on this laminate, the wiring of the driver IC chip can be recognized through the insulating layer. The laminate is characterized in that the heights of the insulating-layer-side surface of the conductive layer are measured as three-dimensional shape data, the data is subjected to two-dimensional Fourier transform expressed by equation (1) to obtain the power spectrum which is a function of a frequency, and the intensity of the frequency corresponding to 600 nm is the value or less corresponding to the height 1.6 μm before the transform. (1) where F(u, v) is the function (power spectrum) created by the transform, u and v are the wave numbers in the x and y directions respectively, f(x, y) is the function (three-dimensional data) to be transformed, and (x, y) are plane coordinates.

Description

 Technical Field The present invention is designed to mount electronic components such as ICs or LSIs.

The present invention relates to a copper-clad laminate for a board. TABE Kei Technology The TAB method (tape, automated bonding) in which a driver IC is mounted on a tape carrier has been used in the electronics industry using liquid crystal display devices (LCD).

 -Also, as a mounting method for higher density mounting in a smaller space, a chip-on-film (COF) in which a bare IC chip is directly mounted on a film carrier tape has been developed.

 The flexible printed circuit board (FPC) used for this COF does not have the device holes used in the TAB method, so when measuring the relative position when mounting the chip, it passes through the insulating layer and passes through the driver IC chip. It is necessary to recognize the wiring of.

As a laminate used for such an FPC for COF, there is a laminate in which an adhesion film such as a nickel film is sputtered on an insulating film such as a polyimide film and then copper plating is applied. In such a copper plating laminate, the polyimide film is relatively transparent, so alignment is easy when mounting the IC, but the adhesive force between the conductor and the insulator is low. There is a problem that it is inferior. As a laminate without such problems, there are a casting type in which a polyimide film is laminated on a copper foil by a coating method, and a thermocompression bonding type in which an insulated film is thermocompressed on a copper foil through a thermoplastic resin or thermosetting resin. There is a laminate.

 However, in the case of the casting type or thermo-compression type laminate, the surface of the insulating layer exposed when the copper foil is removed by etching reflects light irregularly, and penetrates the insulating layer to recognize the wiring of the driver IC chip. There was a problem that could not be done.

 Against this background, a method for producing a copper foil having a small roughness has been proposed. JP-A-2002-73188 discloses a method for polishing an electrolytic deposition surface. Japanese Patent Application Laid-Open No. 2002-021394 (USP 6495022B) discloses a method for producing a roughened layer of copper foil. Japanese Patent Application Laid-Open No. 09-143785 (EP851944) discloses a low-roughness copper foil having a small Rz by using a mercapto compound. Japanese Patent Application Laid-Open No. 2003-23046 discloses an insulator having a prescribed light transmittance.

In these technologies, the method for specifying the roughness of the copper foil surface is calculated by a stylus-type roughness meter, etc. Rz specified in the definition of roughness (Rz) is often used. However, this Rz was incomplete to define the correlation with optical characteristics such as optical scattering, and in some cases it was impossible to actually recognize the wiring of the driver IC chip. For this reason, there has been a demand for the development of a laminate having a conductor surface shape defined by optical characteristics in a low-roughness copper foil. DISCLOSURE OF THE INVENTION The present invention is capable of recognizing the wiring of a driver IC chip through an insulating layer, has a high adhesive force between a conductor and an insulator, and has an excellent electrification port migration resistance. It is intended to provide a laminate. The present inventors have studied to solve the above problems, and as a result, have found that the above problems can be solved by using a conductor layer such as a copper foil constituting a laminate having specific characteristics. The present invention has been completed.

 That is, the present invention provides a laminate in which a conductor layer and an insulating layer are laminated, and measures the surface of the conductor layer on the insulating layer side as three-dimensional shape data including height values at respective points, and obtains the following formula (1) The power spectrum, which is a function of frequency, is calculated by performing the two-dimensional Fourier transform shown in ()), and the intensity of the frequency equivalent to 60 O nm is less than the intensity equivalent to the surface height value of 1.6 m before conversion. It is characterized by being.

 oo oo

 F (U, V)

However,

 F (u, v): Function (power spectrum) obtained by conversion

u, V: wave numbers in X and y directions

ί (X, y): Function to be converted (3D shape data)

 (X, y): plane coordinates

 Here, 1) a laminate whose three-dimensional shape data was measured with an atomic force microscope, 2) a laminate whose three-dimensional shape data was measured at a full scale of 3 to 6 m, 3 ) The conductor layer is a copper foil, and the insulation layer is formed by applying a polyimide precursor resin solution, followed by drying and curing.4) The heat of the insulation layer being thermocompressed to the conductor layer. 5) The fact that the insulating layer is formed of a thermosetting resin layer and an insulating film that is thermocompression-bonded to the conductor layer must be formed by a plastic resin layer and an insulating film. This is a preferred embodiment of the present invention.

Further, the present invention is a COF film carrier tape characterized by using the above-mentioned laminate. Further, the present invention measures the surface of the conductor layer on the insulating layer side as a three-dimensional shape composed of height values at each point, and performs a two-dimensional Fourier transform represented by the above equation (1) to obtain a frequency. Calculate the power spectrum, which is a function of the above, and select a conductor layer whose strength at a specific frequency in the range of 500 to 70'0ηπι is less than the strength corresponding to the surface height value of 1.6 Am before conversion. And a method of manufacturing a laminate having a structure in which a conductor layer and an insulation layer are laminated, wherein an insulation layer is laminated on the conductor layer. Hereinafter, the present invention will be described in detail.

 The laminate of the present invention includes a conductor layer and an insulating layer. As the conductor layer, a copper foil layer is preferable, and the conductor layer may be represented by a copper foil layer in the following description. The conductor layer may be provided on only one side of the insulating layer, or may be provided on both sides. Examples of the conductive layer constituting the laminate include various conductive metal foils. In the case of a copper foil, a rolled copper foil or an electrolytic copper foil may be used.

 As a method of defining the conductor surface shape, three-dimensional shape data consisting of height values at each point on the insulating layer side surface of the conductor layer is measured. As a measuring method, a stylus method, a laser microscope, an atomic force microscope (AFΜ), or the like can be used. Of these, the method using AFM is most suitable for this purpose.

 If the full scale during measurement exceeds 6, it is not possible to measure the details of the surface shape. On the other hand, if it is less than 3 m, irregularities exceeding the full scale will increase, which is inappropriate. Therefore, by setting the full scale from 3 m to 6 m, 3D shape data suitable for subsequent processing can be obtained.

With respect to the three-dimensional shape data, a two-dimensional Fourier transform represented by the equation (1) is performed to calculate a frequency spectrum, which is a function of frequency. The power spectrum obtained by this conversion is obtained by decomposing the periodicity of the three-dimensional shape as a sine wave component and obtaining a two-dimensional image showing its wave number and directionality. In this 2D image, the distance from the center of the image is a sine wave Indicates the wave number, and the direction from the center of the image corresponds to the direction of the sine wave.

 The function Πχ, y) defined in the xy plane coordinate system, that is, the two-dimensional Fourier transform of the three-dimensional shape data is defined by equation (1). Here, u and V indicate the wave numbers in the X and y directions, respectively. F (u, V) indicates the spatial frequency component of f (x, y) corresponding to the wave vector (u, V), that is, the Fourier component.

 The two-dimensional Fourier transform can be performed with commercially available software. In this case, the image is not a continuous function such as Πχ. Y), but a digital data of NXN pixels (pixels) with finite resolution, and a finite sum is used instead of integration using a continuous function. Use the formula used. The digital data used in this case can be obtained by a digital camera, CCD camera, scanner, optical microscope, metallographic microscope, laser microscope, scanning electron microscope, atomic force microscope, or the like.

 In the power spectrum obtained by the two-dimensional Fourier transform, the center of the image is the origin of the uv coordinate system. The intensity at each point in the image corresponds to the magnitude of the Fourier component-components closer to the origin correspond to lower-frequency components, and components farther from the origin correspond to higher-frequency components. The wave number h (1 / m) at the corner farthest from the origin is given by the following equation (2).

h = N / (V ~ 2X Y) (2)

However,

h: wave number (1 / m)

 N: Number of pixels of image before conversion (1)

Y: Actual field of view of image before conversion (m)

当する。 この二次元画像において、可視光波長に対応する 3 8 O nm〜約 7 8 O nmの正弦波成 分の強度にて規定することができるが、 特に、 位置合わせ装置の光源に含まれる波長 であり、 ポリイミド等の高分子の吸収が少なく、 分散されにくい比較的長波長で、 か っ巿販 C C Dカメラの感度が良好である 5 0 O nn！〜 7 0 0 nm、 好ましくは 6 0 O nm に相当する周期性成分の強度をもって規定することで、実用的な透明性を規定できる ことを見出した。 For example, in a 512 × 512 pixel power spectrum obtained by imaging a range of 50 / imX 50 im with 512 pixels × 512 pixels and obtaining a two-dimensional Fourier transform, the four corner positions are at a wave number of 7.24 × 106, wavelength 0.14

Hit. In this two-dimensional image, the intensity of the sinusoidal component from 38 O nm to about 78 O nm corresponding to the wavelength of visible light can be specified, but especially the wavelength included in the light source of the alignment device. Yes, low absorption of high polymers such as polyimide, relatively long wavelength that is difficult to disperse, and good sensitivity of CCD camera. It has been found that practical transparency can be defined by defining the intensity of the periodic component corresponding to 7700 nm, preferably 60 O nm.

 In the laminate that allows the wiring of the driver IC chip to be recognized through the insulating layer, the intensity of the periodic component equivalent to 600 nm corresponds to the surface height value before conversion of 1.6 / m Strength Not more than. Further, it is more preferably 1.5 or less. Here, the intensity equivalent to a surface height value of 1.6 before conversion is 80% of the intensity after conversion and 80% of the intensity after conversion when the two-dimensional shape data before conversion is measured at a full scale of 2 m. When the scale is measured at 4 zm, the converted intensity is 40%, and when the full scale is measured at 6m, the converted intensity is 27%. The insulating layer constituting the laminate is formed by applying a polyimide precursor resin solution and then drying and curing, a thermoplastic resin layer and an insulating film, and a thermosetting resin layer. Any of those formed by using an insulating film may be used.

 Of the insulating layers constituting these laminates, those formed by applying a polyimide precursor resin solution, followed by drying and curing are most suitable, but the present invention is not limited thereto.

 The polyimide precursor resin solution can be produced by polymerizing a known diamine and an acid anhydride in the presence of a solvent.

Examples of diamines used include 4,4'-diaminodiphenyl ether, 2'-methoxy4,4'-diaminobenzanilide, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3 '-Dihydroxy-4,4, -diaminobiphenyl, 4,4' diaminobenzanilide and the like.

 Examples of the acid anhydride include pyromellitic anhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-diphenylsulfonetetracarboxylic acid Acid dianhydride; 4,4'-oxydiphthalic anhydride;

 Each of diamine and acid anhydride may be used alone or in combination of two or more.

 Examples of the solvent include dimethylacetamide, n-methylpyrrolidinone, 2-butanone, diglyme, xylene and the like, and one or more of them can be used in combination. The polyimide-based resin layer is preferably formed by directly applying it on the copper foil layer in a precursor state, and the viscosity of the polymerized resin is preferably in the range of 500 cps to 35,000 O cps. I like it. The applied resin solution is heat-treated, but heat-treated at 100 to 15 Ot for 2 to 4 minutes in the air, and then vacuum-heated to room temperature-340 ° C-room temperature treatment for about 9 hours It is better to do it. The polyimide resin layer may be formed of only a single layer, or may be formed of a plurality of layers. When a plurality of polyimide-based resin layers are used, they can be formed by sequentially applying another polyimide resin on a polyimide-based resin layer composed of different components. When the polyimide resin layer is composed of three or more layers, the same configuration of the polyimide resin may be used twice or more.

A copper-clad laminate, which is a typical example of the laminate of the present invention, can be manufactured by applying a polyimide resin on a copper foil as described above. It can also be manufactured by lamination. The copper-clad laminate thus manufactured may be a single-sided copper-clad laminate having a copper foil layer on only one side, or a double-sided copper-clad laminate having a copper foil layer on both sides. A double-sided copper-clad laminate is formed by forming a single-sided copper-clad laminate and then pressing the copper foil layer by hot pressing. A method in which a film is sandwiched and pressure-bonded by a hot press may be used. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to examples.

 In making the laminate, the following four types of copper foil were prepared.

 1) Copper foil 1: Electrolytic copper foil, Rz 1. O m

 2) Copper foil 2: Electrolytic copper foil, RzO.

 3) Copper foil 3: Rolled copper foil, Rz2. O im

 4) Copper foil 4: Copper foil 3 immersed in 5% hydrochloric acid aqueous solution for 1 minute, Rz2. O m Synthesis example 1

 Put n-methylpyrrolidinone in a thermocouple, stirrer, or reaction vessel into which nitrogen can be introduced. After pouring the reaction vessel into the ice water contained therein, pyromellitic anhydride (PMDA) is charged into the reaction vessel, and then, 4,4'-diaminodiphenyl ether, (anhydro) and 2, -methoxy Introduced 4,4'-diaminobenzanilide (MABA). The total amount of monomer was 15 wt%, the molar ratio of each diamine was MABA: DAPE = 60: 40, and the molar ratio of acid anhydride to diamine was 0.98: 1.0. Thereafter, stirring was further continued, and when the temperature in the reaction vessel became within a range of ± 5 ° C from room temperature, the reaction vessel was removed from ice water, and stirring was continued at room temperature for 3 hours. The solution viscosity of the obtained polyamic acid was 15, OOOcps. Synthesis example 2

After immersing the reaction vessel containing n-methylpyrrolidinone in ice water, PMDA / 3, 3 ', 4, 4'-biphenyltetracarboxylic dianhydride (BTDA) was charged into the reaction vessel, and then 4,4 4 '-Diamino diphenyl ether (DAPE) was introduced. The total amount of monomer input is 15 wt%, The molar ratio of the acid anhydride was BTDA: PMDA = 70: 30, and the molar ratio between the acid anhydride and diamine was 1.03: 1.0. Thereafter, stirring was further continued. When the temperature in the reaction vessel became within ± 5 ° C from room temperature, the reaction vessel was removed from ice water, and stirring was continued at room temperature for 3 hours. The solution viscosity of the obtained polyamic acid was 3,200 cps. Synthesis example 3

 After immersing the reaction vessel containing n-methylpyrrolidinone in ice water, add 3,3'4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA) and PMM to the reaction vessel and then 1,3- Bis (4-aminophenoxy) benzene (TPE-I) was introduced. The total amount of the monomer was 15 wt%, the molar ratio of each acid anhydride was DSDA: DA = 90: 10, and the molar ratio of the acid anhydride to diamine was 1.03: 1.0. Thereafter, stirring was further continued, and when the temperature in the reaction vessel was in the range of from room temperature to 5 ° C in soil, the reaction vessel was removed from the ice water, and stirring was continued at room temperature for 3 hours. The solution viscosity of the obtained polyamic acid was 3J00 cps. Example 1

 (I) Copper foil 1 was used as the copper foil. The surface of this copper foil was shape-measured with an atomic force microscope (NanoScope, a scanning probe microscope manufactured by Digital Instruments) in a range of 50 / im square at a full scale of 4 mm and 256 gradations. One gradation corresponds to 0.0156 m. The obtained image was subjected to two-dimensional Fourier transform using commercially available general-purpose image processing software to obtain a power spectrum. From this power spectrum, the intensity F (U.V) at a position corresponding to a wavelength of 600 nm was measured. Out of 256 gradations, which corresponded to 93 gradations, and the intensity was 36%. This is equivalent to 1.45 xm because the full scale of the shape data before conversion is 4 mm.

The polyamic acid solution of Synthesis Examples 1 to 3 was applied and dried repeatedly on the electrolytic copper foil to obtain a laminate in which a polyimide precursor resin layer was formed on the copper foil layer. At 340 ° C, Heat treatment was performed for 8 hours to obtain a single-sided copper foil laminate having a polyimide thickness of 40 / zm. This laminate has a polyimide layer 3 m generated from the polyamic acid of Synthesis Example 1, a polyimide layer 34 generated from the polyamic acid of Synthesis Example 2, and a polyimide layer generated from the polyamic acid of Synthesis Example 2 on the electrolytic copper foil.

 The laminate was etched with an aqueous ferric chloride solution to obtain a 40 m insulating film. This film was held on the driver IC chip prepared for the test while maintaining a distance of lOO ^ m. The film was mounted on the ponder machine using a commercially available ponder machine (Shinkawa ILT-110). When a 200 m inspection pattern on the IC chip was observed through the film using a CCD camera for alignment, a good image was obtained.

 (II) Copper foil 1 was used as the copper foil. The surface shape was measured in the same manner as in (I) above, except that the target wavelength was set to 300ηιη. The intensity corresponding to the wavelength of 300nm was equivalent to 85 of 256 gradations, and the intensity was 33%. Was. This is equivalent to 1.32 m because the full scale of the shape before conversion is. Comparative Example 1

 (I) Copper foil 2 was used as the copper foil. When the surface shape was measured in the same manner as in Example 1, the intensity corresponding to the wavelength of 600MI was equivalent to 108 of 256 gradations, and the intensity was 42%. This is equivalent to 1.68% since the full scale of the shape data before conversion is 4, in.

 Using this electrolytic copper foil, a laminate was manufactured in the same manner as in Example 1, and an insulating layer film was obtained by etching. When the IC chip was observed through this film, no image could be recognized.

(II) When copper foil 2 was used as the copper foil and the surface shape was measured in the same manner as in (I) above, the intensity corresponding to a wavelength of 300 nm was equivalent to 85 out of 256 tones, and the intensity was Was 33%. Also, since the full scale of the shape data before conversion is 4 mm, 1.32 ffl equivalent <

Comparative Example 2

 When the surface shape was measured in the same manner as in Example 1 using copper foil 3 as the copper foil, the intensity corresponding to a wavelength of 600 nm was equivalent to 119 out of 256 gradations, and the intensity was 46%. It was hot. This is equivalent to 1.86 m because the full scale of the shape data before conversion is 4 m.

 Using this electrolytic copper foil, a laminate was manufactured in the same manner as in Example 1, and an insulating layer film was obtained by etching. When the IC chip was observed through this film, no image could be recognized.

Example 2

 The copper foil 4 was used as the copper foil, and the surface shape was measured in the same manner as in Example 1. The intensity corresponding to the wavelength of 600 im was equivalent to 90 of 256 gradations, and the intensity was 35%. there were. Also, this corresponds to 1.41, ηι since the full scale of the shape data before conversion is 4. "m. Using this pickled rolled copper foil 4, The laminated body was manufactured and etched to obtain an insulated layer film.When the IC chip was observed through this film, a good image was obtained.

 The results are summarized in Table 1. (table 1)

Copper foil 1 Copper foil 2 Copper foil 3 Copper foil 4

Rz (^ m) 1.0 0.8 2.0 2.0

600 nm Λ. Worth "36 36 46 35 Periodicity (%) 93/256 108/256 119/256 90/256 Equivalent height * (im) 1.45 1.69 1.86 1.41

300ηηι c. To Worth. Khutor 33 33

 Periodicity (%) 85/256 85/256

 Equivalent height * (m) 1.33 1.33

 IC chip wiring recognition 〇 X X 〇

* 4 4 for full scale

Industrial potential

The wiring of the driver IC chip can be recognized through the insulating layer, and the adhesion between the conductor and the insulator is high, and a laminate having excellent electromigration resistance can be manufactured.

Claims

The scope of the claims (1) Measure the surface of the conductor layer on the insulating layer side as three-dimensional shape data consisting of height values at each point, and perform a two-dimensional Fourier transform shown in the following equation (1) to obtain a function of frequency. The conductor layer and the insulating layer are characterized in that the intensity at a frequency corresponding to 60 O nm is less than or equal to the intensity corresponding to a surface height value of 1.6 zin before conversion. Laminated structure.  oo oo  F (u, V) -

F (u, v): Function (power spectrum) obtained by conversion u, V: wave numbers in X and y directions f (X, y): Function to be converted (3D shape data)  (X, y): plane coordinates  (2) The laminate according to claim 1, wherein the three-dimensional shape is measured with an atomic force microscope.  (3) The method according to claim 1 or 2, wherein the three-dimensional shape data is measured at a full scale of 3 to 6 m. (4) The conductive layer is a copper foil, and the insulating layer is formed by applying a polyimide precursor resin solution, followed by drying and curing. A laminate according to any one of the above.  (5) The laminate according to any one of claims 1 to 3, wherein the insulating layer is formed of a thermoplastic resin layer thermocompression-bonded to the conductor layer and an insulating film. (6) The laminate according to any one of claims 1 to 3, wherein the insulating layer is formed of a thermosetting resin layer thermocompression-bonded to the conductor layer and an insulating film. (7) A C〇F film carrier tape using the laminate according to any one of claims 1 to 6.  (8) Measure the surface of the conductor layer on the insulating layer side as three-dimensional shape data consisting of height values at each point, and perform a two-dimensional Fourier transform represented by the following equation (1) to obtain a function of frequency. Power spectrum, and select a conductor layer whose intensity at a specific frequency in the range of 500 to 700 nm is less than or equal to the surface height value of 1.6 m before conversion. A method for manufacturing a laminate having a structure in which a conductor layer and an insulating layer are laminated, wherein an insulating layer is laminated on the substrate.  oo CO  F (u, v)

F (u, V): Function (power spectrum) obtained by conversion u, V: wave numbers in X and y directions f (X, y): Function to be converted (3D shape data)  (X, y): plane coordinates