JP2003221456A - Highly adhesive liquid crystal polymer film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal polymer film having high adhesivity. <P>SOLUTION: The highly adhesive liquid crystal polymer film comprises a liquid crystal polymer and has nitrogen atoms on its surface of either one side or both sides wherein the density of the above nitrogen atoms is at least 2% measured by using X-ray photoelectron spectroscopy. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a highly adhesive liquid crystal polymer film, a circuit board using the same, a semiconductor package and a laminate.

[0002]

2. Description of the Related Art Conventionally, chromic acid mixed liquid treatment, corona discharge treatment and the like have been used as a method for improving the surface characteristics of polymer films, but it is highly effective for liquid crystal polymers having high chemical stability. The quality effect cannot be obtained. On the other hand, as a method for improving the surface characteristics of a liquid crystal polymer film, JP-A-10-316777 discloses a method of applying an adhesion-promoting coating on the surface of the film.
No. 24 and JP-A-1-236246,
A method of irradiating ultraviolet rays having a wavelength of 184.9 nm is disclosed in Japanese Patent Application Laid-Open No.
No. 000-49002 proposes a method of performing gas discharge plasma treatment in the presence of a gaseous oxygen atom-containing compound. The method of performing adhesion-promoting coating on the surface of a film described in JP-A-10-316777 is a liquid crystal polymer that is a base material such as acrylic, polyester, polyimide, polyurethane, and polyamide. Therefore, since it is inferior in terms of heat resistance and water absorption, the characteristics of the liquid crystal polymer cannot be utilized. Further, since the coating process is complicated, problems such as an increase in processing cost occur. JP-A-1
In the method of irradiating with ultraviolet rays having a wavelength of 184.9 nm described in JP-A-216824 and JP-A-1-236246, although the adhesiveness with a copper foil or the like is improved,
The adhesive force with the metal layer formed directly on the film by plating or sputtering does not improve so much. Similarly, the adhesive strength with an adhesive such as an epoxy resin or a resin for semiconductor encapsulation is not improved so much. Japanese Unexamined Patent Publication No. 2000-49002 proposes a method of performing gas discharge plasma treatment in the presence of a gaseous oxygen atom-containing compound so that the oxygen concentration on the surface is 1.2 times that of the inside. However, due to the increase in oxygen concentration on the surface, the adhesiveness with copper foil, etc. is improved, but also the adhesiveness with the metal layer directly formed on the film by plating and sputtering, the adhesive such as epoxy resin, and the semiconductor. The adhesive strength with the sealing resin does not improve so much.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal polymer film having high adhesiveness, and to provide a circuit board, a semiconductor package and a laminate using the film.

[0004]

The present inventors have completed the present invention as a result of intensive studies to solve the above problems. That is, according to the present invention, the following liquid crystal polymer film, circuit board, semiconductor package, and laminate are provided. (1) A film made of a liquid crystal polymer, wherein nitrogen atoms are present on one or both surfaces of the film, and the concentration of the nitrogen atoms measured by X-ray photoelectron spectroscopy analysis is 2% or more. Highly adhesive liquid crystal polymer film. (2) The highly adhesive liquid crystal polymer film as described in (1) above, wherein the nitrogen atom is present as an amino group or an amide group. (3) A circuit board comprising a laminate having a metal layer formed on the highly adhesive surface of the highly adhesive liquid crystal polymer film as described in (1) or (2), in which the nitrogen atom is present. . (4) The circuit board as described in (3) above, wherein the metal layer is formed by any method of adhesion, fusion bonding, sputtering, and electroless plating. (5) The circuit board according to (3) or (4), wherein the metal layer is copper. (6) In a semiconductor package having a circuit board in which a semiconductor is sealed with a sealing resin, the circuit board is formed of the circuit board according to any one of (3) to (5). package. (7) A highly adhesive liquid crystal polymer film having a metal layer formed on the highly adhesive surface of the highly adhesive liquid crystal polymer film according to (1) or (2), in which the nitrogen atom is present. / Metal layer laminate. (8) A method for treating a surface of a liquid crystal polymer film, which comprises irradiating the surface-treated surface of the liquid crystal polymer film with an aqueous ammonia solution or an aqueous hydrazine solution, and then irradiating the surface-treated surface with ultraviolet rays having a wavelength of 308 nm. (9) A surface treatment method for a liquid crystal polymer film, which comprises irradiating plasma on the surface-treated surface of the liquid crystal polymer film in an atmosphere of ammonia or hydrazine gas. (10) A highly adhesive liquid crystal polymer film, which is treated by the surface treatment method according to (8) or (9).

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The base film used in the present invention is
It is a hot-melt liquid crystal polymer and has an aromatic polyester structure. Its melting point is 230-380 ° C, preferably 250-350 ° C. Such a liquid crystal polymer has a conventionally known crankshaft unit II
I with mold or vent unit or with linear structure
Included are types of liquid crystal polymers. If the melting point of the liquid crystal polymer film is lower than the above range, it cannot withstand the heat of solder reflow, while if it is higher than the above range, extrusion molding becomes difficult and it becomes unsuitable for sheet formation. The molecular orientation of the film is preferably biaxial orientation,
The MD / TD strength ratio is preferably between 1/3 and 3/1, and more preferably between 1/2 and 2/1. If the strength ratio does not fall within the above range, it is easy to tear and the anisotropy of the coefficient of linear expansion (CTE) becomes strong, so that workability and reliability are deteriorated.

The highly adhesive liquid crystal polymer film of the present invention (hereinafter, also simply referred to as a film) can be produced by subjecting one side or both sides of the liquid crystal polymer film to a nitrogen treatment. The nitriding treatment in this case may be a method capable of immobilizing nitrogen atoms on the surface portion of the liquid crystal polymer film. In such a method, a gaseous or liquid compound having an NH bond at room temperature as a treating agent is used. The various methods used are included. For example, a method of irradiating the liquid crystal polymer film surface with ultraviolet rays in an atmosphere containing a treatment agent, a method of applying a liquid treatment agent to the surface of the liquid crystal polymer film and irradiating it with ultraviolet rays, A method such as plasma electric discharge machining is preferably adopted. When using these methods, if the surface-treated surface of the liquid crystal polymer film is previously irradiated with ultraviolet rays as a pretreatment, the adhesiveness of the liquid crystal polymer film can be further improved. When UV irradiation is performed, UV rays having a wavelength of preferably 308 nm or less, more preferably 254 nm or less, as a main component are used. When the wavelength of ultraviolet rays exceeds the above range, the effect of improving the adhesiveness of the liquid crystal polymer film cannot be sufficiently obtained. The illuminance is preferably 1 mW / cm ² or more at the central wavelength, and the irradiation time is preferably 1 second or more. If the illuminance or irradiation time is insufficient, the effect of improving the adhesiveness of the liquid crystal polymer film cannot be sufficiently obtained. The longer the irradiation time is, the better the adhesion improving effect is. However, considering the manufacturing cost, it is generally considered that the industrially producible time is 60 minutes or less. The distance between the lamp and the liquid crystal polymer film is preferably 5 mm or more and 500 mm or less. If the distance is too short, the film will be deformed by the heat of the lamp, and if the distance is too long, the effect of improving the adhesiveness of the liquid crystal polymer film cannot be sufficiently obtained.

As the compound having the NH bond, ammonia, hydrazine, hydroxylamine and the like are particularly preferably used.

When the liquid crystal polymer film is brought into contact with a treating agent, the concentration of the treating agent is 1 to 100% in the liquid,
Preferably in the range of 10-50%, in gas 1-100
It is preferable to define the amount in the range of mol%, preferably 10 to 100 mol%. The nitrogen atom immobilized in the liquid crystal polymer film is preferably in the form of an amino group and / or an amide group, more preferably in the form of a CNH bond (amino group).

In the present invention, the nitriding treatment is carried out so that the nitrogen atom concentration on the surface portion of the film is 2% (% by weight) or more, preferably 3% or more. The upper limit of the nitrogen atom concentration is not particularly limited, but is usually about 15%.

The nitrogen atom concentration on the film surface is
In X-ray photoelectron spectroscopy, C (Is) and O (I
It is obtained by performing the narrow scan measurement of s) and based on the measurement result of high resolution. In addition, the irradiation X-ray is Al
K _α was used. In this case, the film surface portion means a depth of about 50 to 100 angstroms from the surface of the film, as can be seen from the method for measuring the nitrogen atom concentration.

The highly adhesive film according to the present invention can be firmly adhered to a metal, a plastic film, a thermosetting resin or the like. One preferable product form of the present invention is a film / metal layer laminate in which a metal layer is laminated on the film. Such a laminated body can be manufactured by the following method. (1) Heat-fusion method This method is a method for obtaining a laminate by heat-sealing a metal foil and a film. Examples of the metal foil include various metal foils such as copper foil, aluminum foil, and gold foil. The thickness is usually 0.01 to 200 μm, preferably 0.1 to 50 μm. The heat fusion can be performed by a method such as a general heat press or a double belt press. The processing conditions for heat fusion are the type and thickness of thin metal,
The temperature may be 180 to 400 ° C. and the pressure may be 0.3 to 10 MPa / cm ² , although the temperature may be appropriately selected depending on the conditions such as the melting point and the thickness of the liquid crystal polymer film. (2) Sputtering method This method is a known method in the field of manufacturing electronic circuit boards and optical materials, and is a method of obtaining a laminate by sputtering a metal on a film. Examples of the metal for sputtering include copper, aluminum, gold, tin and chromium. (3) Electroless plating method This method is a known method in the field of manufacturing plated products using non-conductive materials such as plastics and ceramics,
It is a method of obtaining a laminate by depositing a metal on a film from a solution containing metal ions. As a metal,
Examples include copper, nickel, cobalt, gold, tin, and chromium. (4) Method using an adhesive This method is a method for obtaining a laminate by bonding a film and a metal film with an adhesive. As the adhesive, various types such as epoxy type, acrylic type and cyanate type can be used.

In the film / metal layer laminate, the thickness of the film is 10 to 500 μm, preferably 25.
Is about 200 μm. The thickness of the metal layer is 0.01 to 200
μm, preferably 0.1 to 50 μm.

According to the present invention, there is provided a circuit board comprising the film / metal layer laminate. In this case, as the metal, copper, aluminum, gold, tin, chromium or the like is preferably used. The thickness of the film is 10-200 μm,
The thickness is preferably 25 to 125 μm, and the thickness of the metal layer is 3
˜100 μm, preferably 5˜50 μm. In the circuit board of the present invention, the film forming the circuit board is made of a liquid crystal polymer having excellent mechanical strength and heat resistance and extremely low hygroscopicity, and further, the adhesive strength between the film and the metal layer is high. Therefore, it is a high quality product having excellent durability, heat resistance and use stability.

According to the present invention, there is provided a semiconductor package in which a semiconductor is sealed on the circuit board with a sealing resin.
In this case, examples of the sealing resin include epoxy resins of bisphenol type, cresol novolac type, biphenyl type, dicyclopentadiene type, naphthalene type, stilbene type and the like mixed with an inorganic filler. Since the semiconductor package of the present invention uses the circuit board, it is of high quality and excellent in durability, heat resistance and use stability.

[0015]

EXAMPLES Next, the present invention will be described in more detail by way of examples.

Example 1 A 10% aqueous solution of hydrazine was added to a liquid crystal polymer film (manufactured by Japan Gore-Tex, product name "BIAC BA").
50F "), a synthetic quartz plate having a thickness of 4 mm is superposed on the surface thereof to diffuse the aqueous solution on the film, and then the low-pressure mercury lamp PL3 manufactured by Sen Special Light Source Co. is passed through the quartz plate.
UV light having a wavelength of 254 nm was irradiated for 120 seconds using 0-200. The irradiation distance is 4 cm from the lamp
And the irradiation intensity at this time was measured to be 15 mW / c
It was m ² (254 nm).

Example 2 Bell jar type plasma device (PD-10- manufactured by Samco)
S), and a liquid crystal polymer film (manufactured by Japan Gore-Tex, product name “BIAC BA50” between the parallel electrodes.
F ”) is fixed and the inside of the apparatus is replaced with ammonia gas, the pressure is reduced to 0.1 Torr, a high frequency voltage of 13.56 MHz is applied to generate plasma, and the film is processed in a plasma atmosphere for 120 seconds. went.

Comparative Example 1 Sen special light source company low pressure mercury lamp PL30-200
Using the ultraviolet light centered at a wavelength of 254 nm in the air
Liquid crystal polymer film (made by Japan GORE-TEX,
Illuminate the product name "BIAC BA50F") for 120 seconds.
Shot The irradiation distance should be 4 cm from the lamp and
When the radiation intensity is measured, it is 15 mW / cm ²(254n
m).

Comparative Example 2 Bell jar type plasma device (PD-10- manufactured by Samco)
S) was used to fix the film between the parallel electrodes, the inside of the device was replaced with oxygen gas, and the pressure was reduced to 0.1 Torr.
A high-frequency voltage of 3.56 MHz is applied to generate plasma, and a liquid crystal polymer film (manufactured by Japan Gore-Tex, product name "BIAC" is used for 120 seconds in a plasma atmosphere.
BA50F ") was performed.

The properties of the liquid crystal polymer films obtained in the above Examples and Comparative Examples were evaluated. The results are shown in Table 1.

[0021]

[Table 1]

As shown in Table 1, it is understood that when the introduction amount of nitrogen is small, the adhesiveness with electroless plating, sputtering and sealing resin is not excellent.

The evaluation of the above properties was carried out by the following methods. (1) Determination of nitrogen content and form of nitrogen atom: Surface
Product made by Science Instruments, S-
From the spectrum obtained by wide scan measurement using Probe ESCA Model 2803,
After fixing the element, the narrow scan measurement of C (Is) and O (Is) was performed, and it was obtained based on the high-decomposition measurement result. AlK _α was used as the irradiation X-ray. (2) Copper foil adhesive strength (N / cm): manufactured by Nippon Denki Co., Ltd., US
LP-12 foil (electrolytic copper foil, thickness 12 μm, surface roughness of roughened surface: Rz = 1.5) was used for 325 using a vacuum press.
Laminated under press conditions of pressure, 4 MPa, 5 MPa,
A 180 ° peel test was conducted. Table 2 shows the peel test conditions.

[0024]

[Table 2]

(3) Electroless plating adhesive strength (N / c
m): Using the conditions in Table 3 below, after forming an electroless plating layer of copper having a thickness of 0.5 μm, the plating layer further has a thickness of 9 μm.
Copper was electrolytically plated at a current density of 2.5 A / dm ² under the conditions shown in Table 4 to a thickness, and a 180 ° peel test was performed. In addition, in Table 3, chemicals other than chemical substance names are product names of ATOTECH.

[0026]

[Table 3]

[0027]

[Table 4] (4) Sputtering copper adhesion strength (N / cm): After forming a 0.1 μm-thick copper layer on the film surface by sputtering, copper electroplating was further performed until the plating layer became 9 μm thick, and 180 ° peeling was performed. The test was conducted. (5) Sealing resin adhesive strength (MPa): A compound was prepared by mixing cresol novolac type epoxy resin with novolac phenol as a curing agent and fused silica as a filler, molded on a film by transfer molding, and then cured and sheared. The breaking strength was measured. The composition of the molding compound is shown in Table 5 below, and the transfer molding conditions are shown in Table 6. Also,
The conditions for measuring the shear strength are as shown in Table 7.

[0028]

[Table 5]

[0029]

[Table 6]

[0030]

[Table 7]

[0031]

Since the highly adhesive liquid crystal polymer film of the present invention has remarkably improved surface adhesiveness, it is firmly adhered to other materials (metal, plastic, ceramics, glass, etc.). be able to. The film / metal layer laminate in which the metal layer is formed on the film of the present invention is of high quality having excellent durability, heat resistance and use stability. Therefore, by using the laminate of the present invention, it is possible to obtain a high-quality circuit board and a semiconductor package which are excellent in durability, heat resistance, and use stability and have high reliability.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 23/14 H05K 1/03 610N H05K 1/03 610 C08L 101: 02 // C08L 101: 02 H01L 23 / 14 RF term (reference) 4F071 AA04 AA48 AA78 AF12 AF58 AG01 AG15 AG16 AH13 BC01 4F073 AA01 BA25 BB01 CA01 CA45 EA01 EA11 EA43 EA44 4F100 AB01B AB17B AB33B AK41A AS00A AT00A BA02 EC03 J61EJ43EJ58B58 EC03 EC54 E4366

Claims (10)

[Claims] 1. A film comprising a liquid crystal polymer, wherein nitrogen atoms are present on one or both surface portions of the film, and X
A highly adhesive liquid crystal polymer film having a concentration of the nitrogen atom of 2% or more measured by a line photoelectron spectroscopy analysis. 2. The highly adhesive liquid crystal polymer film according to claim 1, wherein the nitrogen atom is present as an amino group or an amide group. 3. A circuit board comprising a laminate having a metal layer formed on the highly adhesive surface of the highly adhesive liquid crystal polymer film according to claim 1 or 2, wherein the nitrogen atom is present. 4. The circuit board according to claim 3, wherein the metal layer is formed by any one of adhesion, fusion bonding, sputtering, and electroless plating. 5. The circuit board according to claim 3, wherein the metal layer is copper. 6. A semiconductor package having a circuit board in which a semiconductor is encapsulated by an encapsulating resin, wherein the circuit board comprises the circuit board according to any one of claims 3 to 5. . 7. A highly adhesive liquid crystal polymer film having a metal layer formed on the highly adhesive surface of the highly adhesive liquid crystal polymer film according to claim 1, wherein the nitrogen atom is present. Metal layer laminate. 8. A method for treating a surface of a liquid crystal polymer film, which comprises immersing the surface-treated surface of the liquid crystal polymer film in an aqueous ammonia solution or an aqueous solution of hydrazine, and then irradiating the surface-treated surface with ultraviolet rays having a wavelength of 308 nm. 9. A surface treatment method for a liquid crystal polymer film, which comprises irradiating plasma on the surface-treated surface of the liquid crystal polymer film in an atmosphere of ammonia or hydrazine gas. 10. A highly adhesive liquid crystal polymer film treated by the surface treatment method according to claim 8 or 9.