JP2000167979A - Flexible double-sided copper-clad board with adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a plate to be laminated with another printed wiring board after forming a circuit, and also enable semiconductor chips or electric and electronic parts to be adhesion secured thereto by laminating reinforcing copper foil via an adhesive layer on an insulation film of a single-sided copper-foiled flexible base material. SOLUTION: A polyamide acid resin solution is flow applied on a carrier film being a base material to be applied with a releasable insulation film resin to then be semi-dried in order to obtain a polyamide acid insulation film. Next, the polyamide acid film, as-attached with the carrier film, is heat press bonded thereto by having the polyamide acid film surface apposite to the copper foil, after that, the carrier film is released therefrom. The copper foil attached with the polyamide acid film is subjected to drying and annealing operation to permit the polyamide acid to be cyclized for polyimide resin, so that a single-sided copper-foiled flexible base material is obtained. Furthermore, an adhesive resin solution is flow applied on the polyimide resin layer, after that, reinforced copper foil is heat bonded on the adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, which is easy to handle in a manufacturing process, is capable of processing a single sheet such as a rigid printed wiring board, and is capable of laminating another printed wiring board or forming a semiconductor chip after forming a circuit. And a flexible double-sided copper-clad board with an adhesive capable of bonding and fixing electric and electronic components.

[0002]

2. Description of the Related Art As semiconductor chips become more highly integrated, a semiconductor package having a large number of input / output terminals is required. In general, there are a type in which the input / output terminals are arranged in a line around the package and a type in which the input / output terminals are arranged in a multi-line not only on the periphery but also on the entire package. The former is QFP (Quad Flat
Package) is typical, and is expected to continue to be mainstream in the future. However, in order to increase the number of terminals, the terminal pitch must be reduced, and in the region of 0.5 mm pitch or less, a high technology is required for bonding with a printed wiring board on which a semiconductor package is mounted. The latter array type is suitable for increasing the number of pins because terminals can be arranged at a relatively large pitch, and a BGA (Ball Grid A)
rray) has also been developed.

[0003] The BGA is classified into a ceramic type, a printed wiring board type, a tape type and the like. Among them, the ceramic type has a shorter distance between the motherboard and the package as compared with a conventional PGA (Pin Grid Array) having connection pins, so that the package is warped due to a difference in thermal stress between the motherboard and the package. There's a problem. Also, the printed wiring board type has problems such as the board thickness being large in addition to the substrate warpage, moisture resistance, reliability, etc., and the BGA using the tape type flexible printed wiring board to which the TAB technology is applied. Is attracting attention. Further, development of a CSP (Chip Size Package) having almost the same size as a semiconductor chip has been actively developed in order to cope with a further reduction in package size. This CSP has a structure in which a semiconductor chip is mounted on a wiring board called an interposer in order to rearrange the electrodes of the semiconductor chip into an area type and to match the pitch with the wiring terminals of the mounting board. As the interposer, a rigid printed wiring board or a flexible printed wiring board is used. However, a flexible printed wiring board is often used due to a demand for a small and thin package and a fine wiring circuit.

Conventionally, as a flexible printed wiring board, a three-layer type in which a copper foil and an insulating film with an adhesive are adhered together by a method such as thermocompression bonding, or a polyamic acid resin solution is applied directly on the copper foil and dried to form an adhesive. A two-layer type for obtaining a polyimide resin flexible printed wiring board without a layer is manufactured. There is also a flexible printed wiring board with an adhesive in which an adhesive layer is provided on an insulating layer of the flexible printed wiring board. This is used for bonding to another printed wiring board or electronic component, or for bonding and fixing a semiconductor chip as an interposer as in the CSP.

However, manufacturing such a flexible printed wiring board with an adhesive has the following problems. When an adhesive layer is formed on an insulating film,
The curl is greatly curled with the adhesive layer inside, which hinders circuit processing and handling. In particular, flexible printed wiring boards used for interposers such as CSP
The purpose is to join the semiconductor chip and the mounting board, and to provide a connection function part at the desired part, remove the insulating film such as polyimide resin by performing laser processing,
It is necessary to provide a connection function by plating or conductive paste. Since most of these are processed by single-wafer processing, if the thickness of the insulating film is small, rigidity is lacking, and handling is significantly reduced. On the other hand, for laser processing or the like, the insulating film of the polyimide resin is preferably as thin as possible.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention has good handling in the manufacturing process, enables single-wafer processing like a rigid printed wiring board, and after forming a circuit, can be bonded to another printed wiring board. Another object of the present invention is to provide a flexible double-sided copper-clad board with an adhesive which can bond and fix a semiconductor chip and an electric / electronic component.

[0007]

Means for Solving the Problems In order to achieve the above-mentioned object, the present inventors have developed an adhesive bonding method in which a reinforcing copper foil is laminated via an adhesive layer on an insulating film of a single-sided copper foil flexible base material. A flexible double-sided copper-clad board with an agent was found, and the present invention was completed.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The flexible double-sided copper-clad board with an adhesive of the present invention is prepared by coating an adhesive on a single-sided copper foil flexible substrate insulating film manufactured by a known method by the method described below. The reinforcing copper foil is laminated via the adhesive layer, and the adhesive has adhesiveness even after the reinforcing copper foil is removed.

A method for producing a flexible double-sided copper-clad board with an adhesive according to the present invention will be described with reference to a typical example. First, in manufacturing a single-sided copper foil flexible base material, a polyamic acid resin (hereinafter abbreviated as polyamic acid) solution is cast onto a carrier film which is a base material to which a resin for an insulating film that can be released is applied, It is semi-dried to obtain a polyamic acid insulating film. Next, the polyamic acid film is thermocompression-bonded with the carrier film, with the polyamic acid film surface facing the copper foil, and then the carrier film is peeled off. The obtained copper foil with a polyamic acid film is dried and annealed to close the polyamic acid to form a polyimide resin to obtain a single-sided copper foil flexible substrate. Further, an adhesive resin solution is cast and applied on this polyimide resin layer, and a copper foil having an effect of reinforcement (reinforced copper foil) is thermocompression-bonded on the adhesive, and the flexible double-sided copper-clad board of the present invention is provided. Get.

A polyamic acid solution used for an insulating film of a single-sided copper foil flexible base material can be obtained by mixing and stirring an acid anhydride, which is a raw material of a polyimide resin, and a diamine in a known solvent. It is necessary that the coefficient of linear expansion of a polyimide resin obtained by heating and imidizing a polyamic acid be smaller than the coefficient of linear expansion of a copper foil. If the coefficient of linear expansion is larger than that of the copper foil, the copper foil is removed when the adhesive is applied, and curling occurs.

As a method for preparing a polyamic acid insulating film by applying a polyamic acid solution, a doctor blade, a knife coater, a bar coater, a curtain coater, a die coater, a roll coater, a reverse coater, or the like can be used.

A metal foil or a resin film can be used as the carrier film on which the polyamic acid used for preparing the insulating film is applied. However, the polyamide acid insulating film obtained here is imidized by high-temperature heating to form a polyimide resin insulating layer. However, it is not preferable that metal foreign matter is contained, and it is preferable to use a resin film. Since the polyamic acid insulating film is used in a semi-dried state, there is no need to apply a high temperature as in the production of a normal polyimide resin film, so that a resin film can be used.

The resin film includes a polyimide resin,
A film made of a resin such as a polyamideimide resin, a polyester resin, a polypropylene resin, or a polyethylene resin can be used. Various release treatments may be performed on the surface of the resin film.

The drying of the polyamic acid insulating film must be completed in a semi-dry state containing a solvent. The solvent content in the semi-dry insulating film is preferably 1 to 20%. If the solvent content is reduced to less than 1% due to excessive drying, sufficient adhesive strength cannot be obtained in the subsequent step of heat lamination with a copper foil, and a flexible printed board cannot be obtained. Insufficient drying and more than 20% of the remaining solvent is not preferable because foaming occurs during heat lamination or the resin flows to cause uneven thickness.

In the method of laminating a polyamic acid insulating film and a copper foil in the production of a single-sided copper foil flexible base material, a roll laminator capable of heating can be suitably used. Lamination may be performed by directly laminating the polyamic acid insulating film with the copper foil.However, the polyamic acid insulating film may be deformed when peeled off from the carrier film or a foreign substance may adhere due to static electricity. It is preferable that the polyamic acid insulating film is laminated with the surface of the polyamic acid insulating film facing the copper foil while the carrier film thus obtained is kept attached to the polyamic acid insulating film. By controlling the heating temperature, the laminating speed, and the laminating pressure, the polyamic acid insulating film and the copper foil are laminated while maintaining a uniform thickness while obtaining a sufficient adhesive strength. The heating temperature varies depending on the resin composition of the polyamic acid used, but is usually at a temperature of 80 ° C to 200 ° C. If the heating temperature is too high, the polyamic acid softens and flows, resulting in a non-uniform thickness, or the solvent component is rapidly vaporized and foamed. If the heating temperature is too low, sufficient adhesive strength will not be obtained, and peeling will occur in the step of heat imidization. The laminating speed is usually high when the heating temperature is high, and slow when the heating temperature is low. If the laminating pressure is too low, sufficient adhesive strength will not be obtained, and if the laminating pressure is too high, the polyamic acid insulating film will flow and thickness unevenness will occur.

The copper foil on which the polyamic acid insulating film is laminated is heated at a high temperature to close the polyamic acid to form a polyimide resin. The maximum heating temperature at this time varies depending on the resin structure of the polyamic acid to be used. However, in a composition having a coefficient of linear expansion smaller than that of a copper foil, heating is usually performed at a maximum temperature of 350 ° C. to 450 ° C. Heating is performed in multiple temperature steps. If the temperature is raised from the beginning, it is not preferable because the solvent component remaining in the polyamic acid insulating film is rapidly vaporized and foamed.

Next, the adhesive used in the present invention is applied to the polyimide resin surface of the obtained copper foil with a polyimide resin film. As a method of applying, the same method as the method of producing the insulating film of polyamic acid can be used.

As the adhesive resin used in the present invention, a thermoplastic resin, a thermosetting resin, or a mixture thereof can be used, but an epoxy resin, a phenoxy resin, a polyether sulfone resin, a polyimide resin, a polyamideimide resin, a polyether resin, An imide resin or the like can be suitably used. In particular, a resin obtained by mixing an epoxy resin with a silicone-modified polyimide resin can be bonded at a low temperature, has a high adhesive strength, and has a low moisture absorption rate, and thus has good moisture resistance reliability. In addition, re-adhesion after removal of the reinforcing copper foil is possible, and no decrease in performance is observed.

The silicone-modified polyimide resin used as the most preferred adhesive resin is characterized by having a polysiloxane structure in the main chain, and the repeating unit of this polysiloxane, -SiR ₁ R ₂ -O- (provided that ,
(R ₁ , R ₂ : monovalent aliphatic or aromatic hydrocarbon group having 6 or less carbon atoms) The repeating number n is preferably 5 to 15, and particularly the value of n is in the range of 6 to 10, the glass transition temperature, It is preferable from the viewpoint of adhesiveness and heat resistance. When n is 4 or less, a high temperature or a long time is required for the bonding step.
In the case described above, the compatibility with the epoxy resin decreases.

The polysiloxane structure is introduced by using a silicone diamine such as α, ω-bis (3-aminopropyl) polydimethylsiloxane and tetracarboxylic dianhydride as raw materials in producing a polyimide resin. As other aromatic diamines, for example, 2,2′-bis (4- (4-aminophenoxy) phenyl) propane, 1,3-bis (3-aminophenoxy) benzene, 2,2 ′ -Bis (4- (4-aminophenoxy) phenyl) hexafluoropropane,
One selected from 2,2′-bis (4-aminophenoxy) hexafluoropropane, bis-4- (4-aminophenoxy) phenylsulfone, bis-4- (3-aminophenoxy) phenylsulfone, and the like, or Two or more aromatic diamines can be used in combination.

The tetracarboxylic dianhydride includes 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and 3,3', 4,4'-benzophenonetetracarboxylic dianhydride. , 4,4'-oxydiphthalic dianhydride, ethylene glycol bistrimellitic dianhydride and the like are preferable. For the reaction of one or two or more tetracarboxylic dianhydrides selected from these groups with the diamine, a known method can be used in an aprotic polar solvent. The polyamic acid solution is heated and dehydrated and cyclized in an organic solvent to obtain an imidized compound, thereby obtaining a silicone-modified polyimide resin.

The most preferred epoxy resin used for the adhesive resin is bisphenol A type, bisphenol F
Type, bisphenol S type, biphenol type, and tetramethyl biphenol type, and the like, and chain-extended epoxy resins. These can be used alone or in combination. The number average molecular weight of the chain-extended epoxy resin is
When the number average molecular weight is less than 2,000, a problem of gas generation occurs due to heating during thermocompression bonding, and when the number average molecular weight exceeds 10,000, the adhesive molding temperature of the adhesive resin increases. Therefore, workability is significantly reduced.

The most preferred adhesive resin used in the present invention is a mixture of the silicone-modified polyimide resin and the epoxy resin, and the mixing ratio thereof is 100 parts by weight of the silicone-modified polyimide resin and 100 parts by weight of the epoxy resin. It is preferably from 70 to 70 parts by weight, particularly preferably from 10 to 40 parts by weight. If the amount is less than 5 parts by weight, the effect of adding a chain-extended epoxy resin to lower the softening temperature of the adhesive resin and increase the low-temperature processability is unlikely to be exhibited. If the amount exceeds 70 parts by weight, the heat resistance of the polyimide resin of the insulating film is impaired. Is not preferred.

As the reinforcing copper foil to be laminated on the adhesive layer used in the present invention, a rolled copper foil, an electrolytic copper foil or the like can be used.
By the lamination of this reinforced copper foil, handling at the time of manufacturing a flexible printed wiring board with an adhesive is improved, and further,
Single-wafer processing of rigid printed wiring boards is also possible. Further, by etching the reinforcing copper foil at a desired position, the adhesive surface can be exposed without damaging the adhesive surface, and a flexible printed wiring board with an adhesive having a reinforcing frame without curl can be obtained. The thickness of the reinforcing copper foil to be used depends on the size of the work, but is preferably 35 to 500 μm. 3
If the thickness is less than 5 μm, the reinforcing effect is small and the rigid printed wiring board cannot be processed through a single-wafer processing step. Also,
If the thickness is more than 500 μm, the cost of etching a copper foil when forming a flexible printed wiring board with an adhesive increases.

As the method for laminating the reinforced copper foil of the present invention, the same method as the method for laminating the polyamic acid film on the copper foil can be used. Further, a lamination press may be used.

[0026]

Hereinafter, the present invention will be described with reference to examples.
It is not limited to these.

Synthesis Example 1 (Synthesis of Polyamic Acid) 450 g of dehydrated and purified NMP was placed in a four-necked flask equipped with a dry nitrogen gas inlet tube, a cooler, a thermometer, and a stirrer.
After vigorous stirring for 10 minutes while flowing nitrogen gas,
42.0 g of 2-bis (4- (4-aminophenoxy) phenyl) propane (BAPP) was added, and the mixture was stirred until it became uniform. While the system was cooled to 20 ° C. or lower in a water bath, 33.0 g of benzophenonetetracarboxylic acid was gradually added to cause a polymerization reaction to obtain a polyamic acid varnish.

Synthesis Example 2 (Synthesis of Silicone-Modified Polyimide Resin) 791 g of dehydrated and purified NMP was placed in a four-necked flask equipped with a dry nitrogen gas inlet tube, a cooler, a thermometer, and a stirrer.
After vigorously stirring for 10 minutes while flowing nitrogen gas, BA
73.9 g of PP, 17.5 g of 1,3-bis (3-aminophenoxy) benzene (APB) and 50.2 g of α, ω-bis (3-aminopropyl) polydimethylsiloxane (average molecular weight: 837) were added, and the system was charged. Was heated to 60 ° C. and stirred until uniform. The system is then cooled to below 5 ° C. in an ice water bath,
44.1 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 61.5 g of ethylene glycol bistrimellitic dianhydride (TMEG) were added in a powder state over 15 minutes, Thereafter, stirring was continued for 3 hours. During this time, the flask was kept at 5 ° C. or lower. Thereafter, the nitrogen gas inlet tube and the condenser were removed, a Dean-Stark tube filled with xylene was attached to the flask, and xylene 1 was added to the system.
98 g were added. The system was heated to about 175 ° C. in place of an oil bath, and generated water was removed from the system. After heating for 4 hours to stop the generation of water from the system, the system was cooled and the reaction solution was poured into a large amount of methanol to precipitate a silicone-modified polyimide resin. After the solid content was filtered, the residue was dried under reduced pressure at 80 ° C. for 12 hours to remove the solvent and 227.8 g (yield 9).
2.1%) of a solid resin. The obtained silicone-modified polyimide resin has a glass transition temperature of 148 ° C.,
It was confirmed that the compound was well dissolved in dimethylformamide (DMF) and 1,4-dioxane (1,4-DO).

Synthesis Example 3 (Synthesis of chain-extended epoxy resin) In a flask equipped with a thermometer and a stirrer, 100.0 g of tetramethylbiphenol diglycidyl ether (YX4000H, manufactured by Yuka Shell Epoxy Co., Ltd.) was placed, and the temperature was raised to 130 ° C. After heating and melting, 48.4 g of bisphenol A (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred until uniform.
After that, triphenylphosphine (Wako Pure Chemical Industries, Ltd.)
1.00 g) at 130 ° C. for 3 hours and 180 ° C. for 1 hour.
After stirring for an hour, a chain-extended epoxy resin was obtained.

Example 1 On a 75 μm thick polyester resin film as a carrier film, a linear expansion coefficient after imidization was 10 ppm.
Was applied with a die coater and dried at 100 ° C. for 10 minutes to obtain a polyamic acid insulating film having a thickness of 50 μm. 18
The above polyamic acid film was superimposed on a rolled copper foil having a thickness of μm (manufactured by Nippon Mining Co., Ltd.), and heated and pressed at 140 ° C. with a roll laminator. The obtained polyamic acid film with copper foil was continuously heated at 150 ° C., 200 ° C. and 250 ° C. in a nitrogen dryer.
℃, 300 ℃, 350 ℃ for 15 minutes each, further 4
It was heated at 00 ° C. for 2 hours to perform imidization. The polyimide resin layer after imidization had a thickness of 25 μm and was curled with a radius of curvature of 50 cm with the copper foil inside. An NMP solution of an adhesive resin in which the silicone-modified polyimide resin of Synthesis Example 2 and the chain-extended epoxy resin of Synthesis Example 3 were mixed at a ratio of 4: 1 was cast and coated on the polyimide resin layer with a bar coater, and then heated at 80 ° C. , 150 ℃, dried at 220 ℃ 3 minutes each,
An adhesive layer of 10 μm was formed. The obtained flexible single-sided copper-clad board with adhesive is
The peel strength at the time of thermocompression bonding at 50 ° C. for 10 seconds is 1.
It was 5 kg / cm. An electrolytic copper foil having a thickness of 70 μm was laminated and pressed at a pressure of 30 kg / c at a temperature of 210 ° C. for 30 minutes on the adhesive surface of the flexible single-sided copper-clad board with an adhesive to obtain a flexible double-sided copper-clad board with an adhesive. The obtained flexible double-sided copper-clad board with an adhesive was capable of single-wafer processing without warpage. Also, after the reinforcing copper foil was etched, the peel strength when the semiconductor chip was heated and pressed at 250 ° C. for 10 seconds with the circuit surface of the semiconductor chip was unchanged at 1.5 kg / cm.

[0031]

According to the flexible double-sided copper-clad board of the present invention, a single-wafer processing such as a rigid printed wiring board can be performed with good handling. An element or an electric / electronic component can be adhered and fixed, and a flexible printed wiring board with an adhesive having no curl and excellent heat resistance can be obtained.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshitaka Okugawa 2-5-8 Higashishinagawa, Shinagawa-ku, Tokyo Sumitomo Bakelite Co., Ltd. F-term (reference) 4F100 AB17C AB33C AK41 AK46 AK49G AK52G AK53G AL05G AL06G AR00B AT00A BA03 BA07 BA10A BA10C BA31 CB00B GB43 JG04A JK17A JL01 JL05 JL11 JL11B

Claims (3)

[Claims] 1. A flexible double-sided copper-clad board with an adhesive in which a reinforcing copper foil is laminated on an insulating film of a single-sided copper foil flexible base material via an adhesive layer. 2. The flexible double-sided copper clad board with an adhesive according to claim 1, wherein the adhesive has an adhesive property even after removing the reinforcing copper foil on the adhesive side. 3. The flexible double-sided copper-clad board with an adhesive according to claim 1, wherein the resin of the adhesive is a mixture of a silicone-modified polyimide resin and an epoxy resin.