JPH0747717B2 - Adhesives on polyimide films and methods of making them - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to microelectronic circuit packages,
In particular, it relates to microelectronic circuit packages having a ductile, tear resistant, low dielectric constant polymer core. More particularly, the invention relates to circuit packages formed from organic polymer films sandwiched with a thermosetting insulating adhesive therebetween. This microelectronic circuit package is made from multiple thin insulating layers formed from a composite of thermosetting organic adhesive and organic polymer film.

Another aspect of the invention is a composite formed from a thermosetting organic adhesive and an organic polymer film. These thermosetting insulating adhesives can be used to (1) between multiple organic films within individual insulating layers of a circuit package, and (2) the insulating layer and its circuitry.
It is used to give adhesiveness between

These adhesive compositions cure at reduced temperatures resulting in (1) a low dielectric constant, (2) a high degradation temperature,
And (3) products such as composites bonded by adhesive can be produced, which are characterized by flame retardancy.

[0004]

BACKGROUND OF THE INVENTION General structures and manufacturing methods for electronic packages are described, for example, in Donald P. Seraphim, Ronald Las
ky, Che-Yo Li, Principles of Electronic Packa
ging , McGraw-Hill Book Company, New York, New York
(1988), and Rao R. Tummala and Eugene J. Ryma
szewski, Microelectronic Packaging Handbook , Van N
ostrand Reinhold, New York, New York (1988), both of which are incorporated herein by reference.

Electronic packages include integrated circuit chips,
Through modules, cards, and boards, it extends to gates and systems. An integrated circuit "chip" is called a "zero order package". The zero-order package enclosed inside this chip or its module is called the first level packaging. Integrated circuit chips provide circuit component to circuit component and circuit to circuit interconnection, heat dissipation, and mechanical integrity.

There is at least one other level of packaging. The second level packaging is the circuit card. The circuit card performs at least four functions. First, this circuit card is used because the total circuit or bit count required to perform the desired function exceeds the bit count of the first level package, i.e. the chip, so that this This is because multiple chips are needed to perform the function. Second, the circuit card provides signal interconnection with other circuit elements. Third, the second level package, i.e. the circuit card, provides sites for components that are not easily integrated in the first level package, i.e. the chip or module. These components include, for example, capacitors, precision resistors, inductors, electromechanical switches, optical couplers, and the like. Fourth, this second level package allows for thermal management, or heat dissipation. And now several cards can be mounted on one board.

The card and substrate may be polymer-based or ceramic-based. The basic method for polymer-based composite package manufacturing is described by Seraphim, Lasky, and Li, previously incorporated herein by reference.
Principles of Electronic Packaging , 334-371
“Polymers and Polymer Based Composites”
for Electronic Applications ”in George P. Schmit
t, Bernd K. Appelt and Jeffrey T. By Gotro
And Tummala and Rymaszewski, Microelectronics Packa , also previously incorporated herein by reference.
Ging Handbook , pp. 853-922, "Printed C"
Donald P. Seraphim, D in “ircuit Board Packaging”
onald E. Barr, William T. Chen, George P. Schmitt
And Rao R. The "prepreg" method described by Tummala.

In the "prepreg" process for making polymeric electronic circuit packages, fibrous objects, such as nonwoven mats or woven webs, are impregnated with a laminating resin, or adhesive. This step consists of coating the fibrous body with, for example, an epoxy resin solution, evaporating the solvent associated with the resin, and partially curing the resin. This partially cured resin is B-
Called stage resin. The body of fibrous material and the B-staged resin are prepregs. This prepreg, which is easy to handle and stable, may be cut into sheets for subsequent processing.

Typical resins used to make prepregs include epoxy resins, cyanate ester resins, polyimides, hydrocarbon-based resins, and fluoropolymers. One type of prepreg is FR-4 prepreg. FR-4 has an epoxy resin of 2,2 '
-A flame-retardant epoxy glass cloth material which is a diglycidyl ether of bis (4-hydroxyphenyl) propane. This epoxy resin is also known as the diglycidyl ether of bisphenol A (DGEBA). The flame retardancy of FR-4 prepreg is about 15-
Obtained by containing 20% by weight of bromine.
This is done by incorporating the appropriate amount of resin or other brominated compound.

Still other bisphenol A diglycidyl ether resins are used to make rigid circuit boards. Some resins used to make reinforced prepreg "prepregs" for circuit boards impart some degree of flame retardancy as disclosed by US Pat. No. 4,782,116. Including a resin bromine substituted for
There is a relatively low molecular weight bisphenol A diglycidyl ether epoxy resin. Such epoxy resin is
For example, using a non-brominated resin, one having a relatively low equivalent weight in the region of 180-200, so that the epoxy group content is relatively high, ie each relatively short repeating unit comprises two epoxy groups. , Which results in an increase in the dielectric constant of the composition after curing.

Other epoxy resin formulations useful in providing prepreg include high functionality resins such as epoxidized cresol novolacs, and epoxidized derivatives of tris (hydroxyphenyl) methane.
These multifunctional epoxy resins have a high glass transition temperature,
It is characterized by high thermal stability and low uptake of water.

Phenolic cured epoxies such as Ciba-Giegy RD86-170 ^{(TM )} , Ciba-Giegy RD
87-212 ^(TM) , Ciba-Giegy RD87-21
2 ^(TM) , DowQuatrex ^(R) 5010 ^(TM) , Shell Epon ^(R) 1
151 ^{(TM) and the} like are also used in the production of prepreg. These epoxies are a mixture of epoxies, each epoxy having at least two functional groups, a phenolic hardener having at least two functional groups, and an imidazole catalyst.

Cyanate ester resins are also used in making prepregs. One type of cyanate ester resin is dicyanate reacted with methylenedianiline bis-maleimide. This product can also be reacted with a compatible epoxide to form a three component laminate material. One such laminated material is 50: 45: 5 (parts by weight) epoxy: cyanate: maleimide. Typical examples of cyanate ester resins useful in making prepregs are the products of bisphenol A dicyanate and epoxy, which polymerize during lamination to form a crosslinked structure.

One polyimide used in adhesive-bearing films in film-adhesive systems is DIMENS.
IONALLY STABLE POLYIMIDE FILM AND PROCESS FOR PREP
Kiyoshi Kumagawa, Kenji K on ARATION THEREOF
Polyimides based on diphenylene dianhydride described in U.S. Pat. No. 4,725,484 to uniyasu, Toshiyuki Nishino and Yuji Matsui. This patent
3,3 ', commercially known as Upilex ^(R) S
Copolymers of 4,4'-biphenylenetetracarboxylic dianhydride and p-phenylenediamine are described.

One proposed adhesive mixture contains a significant amount of epoxy resin relative to the dicyanate polymer, which provides an even higher dielectric constant. Also in such compositions, the glass transition temperature and processing or curing temperature are generally reduced such that the thermal stability of the cured prepreg or laminate is insufficient for high temperature processing applications. .

However, the currently known film-adhesive systems and fiber-adhesive systems have drawbacks. For example, epoxy-glass systems have relatively high dielectric constants and relatively poor thermal stability, while polyimide-glass systems have poor copper peel strength. Attempts to replace polymer fibers or films instead of glass fibers have led to problems of microcracking and poor mechanical properties.

[0017]

OBJECTS OF THE INVENTION Thus, one object of the present invention is to provide an organic polymer film-adhesive composite for microelectronic circuit packages having a relatively low thermal constant while having relatively good thermal stability and mechanical properties. It is to provide things.

Another object of the present invention is to provide a thermally stable composite of dicyanate-diepoxy adhesive and polyimide having a low dielectric constant for microelectronic circuit packages.

[0019]

SUMMARY OF THE INVENTION The compositions and methods of the present invention alleviate the deficiencies of the prior art and achieve the objects of the invention. According to the present invention, a polymer film carrying a thin film adhesive resin is provided, wherein the resin and the polymer film interact synergistically to produce a low dielectric constant,
It provides high thermal stability and high mechanical strength.

This resin is a polymer product of (a) diglycidyl bisphenol p-dialkylbenzene and (b) dicyanate diphenylhexafluoroisopropane. Preferably, the resin is about 5-40% by weight.
Diglycidyl bisphenol p-dialkylbenzene, and about 60-95% by weight dicyanate diphenylhexafluoroisopropane.

The resin is present as a thin film on top of the thin film of polymer to form an organic polymer insulating composite. The composite is a thin film of organic polymer polyimide, as well as (1) diglycidyl bisphenol p.
-Formed from an organic polymer adhesive reactant of dialkylbenzene and (2) dicyanate diphenylhexafluoroisopropane. This thin film of organic polymer
Acts as a backing layer, carries and reinforces a thin film of adhesive.

In the preferred illustration of the invention, the organic polymer film is a polyimide. Particularly preferred polyimide thin films are copolymers of 3,3 ', 4,4'-biphenylenetetracarboxylic dianhydride and diamines such as p-phenylenediamine, 4,4'-diaminophenyl oxide and mixtures thereof. .

The composite is particularly useful as a layer in electronic circuit packages, such as multilayer printed circuit cards or substrates. For example, the electronic circuit package can and does contain at least one microelectronic integrated circuit chip. This IC chip is
It has signal leads, power leads, and ground leads that communicate with corresponding circuit elements in the circuit package. The circuit package is a stack of individual cores, and at least one layer or core constitutes the substrate of the organic polymer insulating composite described above.

According to yet another illustration of the invention, there is provided a method of making a circuit board layer. The method comprises the steps of providing a thin film of polyimide, contacting and coating and / or impregnating the thin film of polyimide with the adhesive composition of the present invention. The thin film of polyimide thus treated, i.e. coated and / or impregnated, is subsequently partially cured to produce a film-based prepreg. This step, and subsequent steps, may be carried out in equipment used to produce conventional prepregs. Subsequent steps form a layer of adhesive-a thin film of polyimide-a few plies of adhesive to form a circuit board layer, circuitize this circuit board layer, and another circuit board layer. Laminating to a circuit board layer. Of course, it should be understood that the circuitization and stacking can be performed in various orders to form the power core, internal circuitization, external circuitization, and contacts, leads, and housing.

[0025]

DETAILED DESCRIPTION According to the present invention, a polymer film reinforcing resin, which resin and these polymer films interact synergistically to have a low dielectric constant, a high thermal stability, and a high mechanical strength. A resin having is provided.

This resin is (a)

[Chemical 1] Diglycidyl bisphenol p-dialkylbenzene having the formula represented by and (b)

[Chemical 2] Is a polymer product of dicyanate diphenylhexafluoroisopropane having a structural formula represented by:

Preferably, the resin comprises about 5-40% by weight diglycidyl bisphenol p-dialkylbenzene and about 60-95% by weight dicyanate diphenylhexafluoroisopropane.

The resin is supported and reinforced by a thin film of polymeric polyimide in an organic polymeric insulating composite. The composite comprises an organic polymer film as described in more detail herein below, and an organic polymer of (1) diglycidyl bisphenol p-dialkylbenzene and (2) dicyanate diphenylhexafluoroisopropane. Formed from an adhesive reactant. This thin film of organic polymer acts as a supporting and reinforcing layer for the adhesive.

In a preferred illustration of the invention, the thin film of organic polymer comprises polyimide. A particularly preferred polyimide film is a copolymer of 3,3 ', 4,4'-biphenylenetetracarboxylic dianhydride and 4,4'-diaminophenyl oxide or p-phenylenediamine. This copolymer

[Chemical 3] [Where R is

[Chemical 4] Or

[Chemical 5] And has a structural formula represented by

The composite is particularly useful as a layer in printed circuit cards or substrates used in electronic packaging. For example, a printed circuit board or card 1 shown in FIG. 1 and also referred to as an electronic circuit package, can and will contain at least one microelectronic integrated circuit chip 5. This I
The C-chip 5 communicates with the corresponding circuit elements in the circuit package 1 through the chip carrier 9 and has leads 7, for example signal leads 7a, power leads 7b, and ground leads 7c. The circuit package 1 is a stack of individual cores 11, and at least one layer or core 11 constitutes the substrate of the organic polymer insulating composite mentioned above. The individual layers 11 of the package 1 may be power cores, embedded signal circuitry or external signal circuitry 1.
7 can be carried.

In accordance with yet another example of the present invention, illustrated in the flow chart of FIG. 2, there is provided a method of making a circuit board layer, and a more complete circuit board or card. The method comprises the steps of providing a thin film of an organic polymer, i.e. a coated polyimide film.
This thin film is fed through a dip tank or bath of adhesive precursor. In the case of the present invention, this is 5-40% by weight of Shell Chemical Company RSL.
-1107 ^(TM) diglycidyl bisphenol p-dialkylbenzene, 60-95 wt% Hi-Tek Polymer
s, Inc. Dicyanate diphenylhexafluoroisopropane, and 0.1 parts by weight of resin as a catalyst.
A bath of 05 parts zinc octoate (8% by weight zinc in mineral oil spirits).

The next part of the impregnation process heats the wet film to drive off the solvent and then polymerize the adhesive.
Polymerization may be carried out by heating the moist film sufficiently hot to react the monomer components of the adhesive and produce a prepolymer, or B-staged resin. This is about 140 ° C. for about 5 minutes.

Alternatively, even pressing or lamination can be combined with polymerization. Thus, the prepolymer can be used to produce about 150 pounds per square inch
About 30 at a temperature of about 200 ° C. or higher in a laminating press with an applied pressure of about 300 pounds per square inch.
Allow to polymerize for minutes. Lamination and curing are in multiple stages, eg, 200 ° C. for 30 minutes, followed by 250-300.
Alternating can be carried out in a two-step process such as 30 minutes at ° C.

Subsequent steps include core stacking, power core circuitization, embedded signal circuitization, panel stacking, external circuitization, and contact application. It should, of course, be understood that the circuitization and lamination may be performed in various orders to form the power core, internal circuitization, external circuitization, and contacts, leads, and housing.

The present invention provides for the low dielectric constant adhesive reaction formation of certain high molecular weight epoxy resin precursors having epoxide equivalent weights of about 185 to about 260 with dicyanate diphenylhexafluoroisopropane monomer or prepolymer. And the reaction product synergistically interacts with the low dielectric constant polymer film to provide (1) thermal stability under microelectronic circuit package manufacturing conditions, as well as ( 2) Based on the discovery that low dielectric constant composites can be produced that provide thermal, adhesive and elastic properties that are neither brittle nor microcracked.

In a preferred illustration of the present invention, the novel dicyanate-epoxy blend composition of the present invention is cured in the presence of a polymeric film, such as a polyimide film, to give an organic polymeric circuit board having a low dielectric constant. However, it should be understood that the novel dicyanate-epoxy blend composition can also be used to provide adhesion to circuit board layers.

Aromatic fluorinated dicyanates are generally polymerized by cyclic trimerization to give a highly cross-linked, highly temperature stable, low dielectric constant, high glass transition temperature and flame retardant UL94 V-0 rating. To produce a heteropolymer.

The diepoxide compound and the prepolymer are
Generally, the epoxide groups are polymerized by ring opening to produce hydroxyl terminated polyether chains.

An aromatic dicyanate of the present invention and the formula:

[Chemical 6] Blends of a small amount of a mixture of aromatic epoxy prepolymers having R, wherein H is H or lower alkyl, preferably methyl, with from about 5% to about 40% by weight of epoxide groups It is believed to react with excess aromatic cyanate groups in the mixture to form a 5-membered ring oxazoline group during crosslinking or curing. The formation of these 5-membered rings either eliminates the number of hydroxy groups formed or substantially reduces it from the number normally formed during curing of the epoxy resin.

A preferred epoxy resin precursor is diglycidyl-α, α'-bis (4-hydroxyphenyl)-, having the formula given above herein, wherein each R is methyl. p-diisopropylbenzene or an oligomer thereof.

The presence of more epoxy functional groups than aromatic dicyanate functional groups, or the use of epoxide resins having an epoxide equivalent weight of less than about 200, results in the formation of a greater number of polar groups in the cured resin and dielectric. It results in a considerable and undesired increase in the constant. Polymers containing greater than about 40 wt% epoxy component have low dielectric constant and high thermal stability properties or UL94.
It is not satisfactory for polyimide film-containing prepregs and circuit boards that require V-0 or V-1 flame retardancy evaluation.

The preferred aromatic dicyanates used according to the invention are the fluorinated dicyanates disclosed in US Pat. No. 4,745,215, most particularly 6-F bisphenol A dicyanate. Such materials, when used alone, i.e. without epoxide functional groups, and when impregnated into conventional E-glass reinforced fabrics and cured at 250 ° C, have a glass transition temperature of about 240 ° C to 260 ° C, A thermal stability represented by a dielectric constant of about 3.3, a water absorption of 0.45% at room temperature and a weight loss (isothermal, 1 hour) of 1.0% at 350 ° C and 7.8% at 400 ° C; It has a heat degradation temperature of about 450 ° C. Furthermore, such materials are flame retardant and have a flammability rating of UL94 V-0.

For control, 0-40% by weight of diglycidyl bisphenol p-dialkylbenzene was blended with dicyanate diphenylhexafluoroisopropane and 3,3 ', 4,4'-biphenylene tetracarboxylic acid dicarboxylic acid. Ube I of anhydride and p-phenylenediamine
ndustries Ltd. When Upilex ^(R) impregnated coated on a thin film of R polyimide copolymers and / or within it to produce a composite of the present invention, the adhesive and the composite produced has properties in Table 1 .

[0044]

[Table 1]

Similar non-fluorinated aromatic dicyanates require the addition of conventional flame retardants such as brominated polyvinyl benzyl ether or brominated diphenyl, in order that they impart flame retardant properties, and such The additive substantially affects the dielectric constant and therefore cannot be used in accordance with the present invention. However, this does not preclude the use of non-fluorinated aromatic dicyanates such as bisphenol A dicyanate in admixture with fluorinated dicyanates.

In addition to the fluorinated dicyanate and epoxy resin precursors, the composition is also preferably by solution of a suitable conventional polymerization catalyst such as zinc, cobalt, copper, or manganese octoate or naphthenate, and nonylphenol. Includes octoates and naphthenates exemplified by the more latent acetylacetonates dissolved therein.

[0047]

Having described the basic concept of the invention, reference will now be made to the following example, which is provided by way of illustration and not by way of actual limitation of the invention. All parts and%
Is by weight unless otherwise noted.

Example 1 40 parts by weight of Shell Chemical Company RSL-110
7 ^(TM) diglycidyl bisphenol p-dialkylbenzene, 80 parts by weight of Hi-Tek Polymers, Inc. Aro
CY-40S ^(TM) dicyanate diphenylhexafluoroisopropane and a resin composition comprising 0.03 parts by weight zinc octoate (8% by weight zinc in mineral oil spirits) in 90 parts by weight methyl ethyl ketone are prepared. . This resin composition was manufactured by Ube Industries, Ltd. Upi
Apply to a 2 mil thick film of lex SGA ^(TM) .

The moist film is heated to 140 ° C. for 2-3 minutes to form the B-stage resin. In this way, a composite is obtained having an adhesive film of a thin film of epoxide-cyanate B-stage resin on a thin polyimide film. The composite structure is then placed in layers between sheets of 1 ounce copper foil, placed in a heated press, and 150-300 per square inch.
Heat to 200 ° C. for 30 minutes and then 250-300 ° C. for 30 minutes while maintaining pound pressure.

A cured laminate having an adhesive epoxide-cyanate film on a thin polyimide film is obtained.

Example 2 20 parts by weight of Shell Chemical Company RSL-110
7 ^(TM) diglycidyl bisphenol p-dialkylbenzene, 106.4 parts by weight of Hi-Tek Polymers, Inc. A
Produce a resin composition comprising rocy-40S ^(TM) dicyanate diphenylhexafluoroisopropane and 0.05 parts by weight zinc octoate (8% by weight zinc in mineral oil spirits) in 90 parts by weight methyl ethyl ketone. . This resin composition was manufactured by Ube Industries, Ltd. Up
Apply to ilex SGA ^(TM) 2 mil thick film.

The wet film is heated to 140 ° C. for 2-3 minutes to form the B-staged resin. In this way, a composite is obtained having an adhesive film of a thin film of epoxide-cyanate B-stage resin on a thin polyimide film. The composite structure is then placed as a layer between multiple sheets of 1 ounce copper foil. The composite structure is then placed in a heated press and, while maintaining a pressure of 150-300 pounds per square inch, 2
3 minutes at 00 ° C for 30 minutes and then 250-300 ° C
Heat for 0 minutes.

A cured laminate having an adhesive epoxide-cyanate film on a thin polyimide film is obtained.

Although the present invention has been described in terms of preferred embodiments and illustrations, it is not intended to limit the scope of the invention thereto, but the invention is limited only by the claims appended hereto. To be done.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a microelectronic circuit package including an organic polymer insulating layer of the present invention.

FIG. 2 is a flow chart of a method for making a microelectronic circuit package including an organic polymer insulating layer of the present invention.

[Explanation of symbols]

 1 electronic circuit package 5 ultra-small electronic integrated circuit chip 7 lead wire 9 chip carrier 11 core 17 external signal circuit

Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09J 7/02 JLE H01L 23/12 23/14 H05K 3/38 E 7011-4E 3/46 Q 6921-4E / / C09J 163/02 JFL 179/04 JGC (72) Inventor Constantinos Papatomas New York, USA 13760. End cot. Coventry Road 75 (72) Inventor Lee Paul Springer New York, USA 13760. End cot. Grand View Place 2606 (72) Inventor William J. Joseph Suma 13760, New York, USA. Endwell. Elm Wood Drive 1022 (72) Inventor David Way One New York, USA 13850. Vestal. Oberbrutsk Drive 800

Claims (8)

[Claims] 1. An organic polymer film comprising (a) an organic polymer film and (b) (1) diglycidyl bisphenol p-dialkylbenzene and (2) dicyanate diphenylhexafluoroisopropane. An organic polymer insulating composite in which a film carries and reinforces the adhesive reactant. 2. The organic polymer adhesive reactant is about 5-4.
An organic polymer insulating composite according to claim 1 which comprises 0% by weight of diglycidyl bisphenol p-dialkylbenzene and about 60 to 95% by weight of dicyanate diphenylhexafluoroisopropane. 3. The organic polymer insulating composite according to claim 2, wherein the organic polymer film is made of polyimide. 4. The organic polymer film is (1) 3,
From a polyimide having a moiety of a diamine selected from the group consisting of 3 ', 4,4'-biphenylene tetracarboxylic dianhydride and (2) p-phenylenediamine, 4,4'-diaminophenyl oxide and mixtures thereof. The organic polymer insulating composite according to claim 3, which comprises: 5. An electronic circuit package adapted to accommodate at least one microelectronic circuit chip having a signal lead, a power lead, and a ground lead, the circuit package being a stack of individual cores. At least one core comprises (a) an organic polymer film and (b) (1) diglycidyl bisphenol p-dialkylbenzene and (2) an organic polymer adhesive reaction product of dicyanate diphenylhexafluoroisopropane. The organic film comprises a substrate of an organic polymer insulating composite carrying and reinforcing the adhesive reactant, and the inner core of the laminate has at least one surface on at least one surface thereof. A package with a Cu circuitization that allows it to cooperate with one of the leads. 6. The organic polymer adhesive reactant is about 5-4.
6. A composition comprising 0% by weight diglycidyl bisphenol p-dialkylbenzene and about 60-95% by weight dicyanate diphenylhexafluoroisopropane.
Electronic circuit package as described. 7. The electronic circuit package of claim 6, wherein the organic polymer film comprises polyimide. 8. The film comprises (1) 3, 3 ', 4,
4. A polyimide having a diamine moiety selected from the group consisting of 4'-biphenylene tetracarboxylic dianhydride and (2) p-phenylenediamine, 4,4'-diaminophenyl oxide, and mixtures thereof. 7. The electronic circuit package described in 7.