WO1990012668A1 - Apparatus and method for fabricating printed circuit boards - Google Patents

Apparatus and method for fabricating printed circuit boards Download PDF

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Publication number
WO1990012668A1
WO1990012668A1 PCT/US1990/002139 US9002139W WO9012668A1 WO 1990012668 A1 WO1990012668 A1 WO 1990012668A1 US 9002139 W US9002139 W US 9002139W WO 9012668 A1 WO9012668 A1 WO 9012668A1
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WO
WIPO (PCT)
Prior art keywords
substrate surface
printed circuit
means
substrate
conductor
Prior art date
Application number
PCT/US1990/002139
Other languages
French (fr)
Inventor
George Anthony Salensky
Thomas Steven Thoman
Original Assignee
Amoco Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US34374689A priority Critical
Priority to US343,746 priority
Application filed by Amoco Corporation filed Critical Amoco Corporation
Publication of WO1990012668A1 publication Critical patent/WO1990012668A1/en

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Classifications

    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00Apparatus or processes for manufacturing printed circuits
    • H05K3/10Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
    • H05K3/20Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern by affixing prefabricated conductor pattern
    • H05K3/207Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern by affixing prefabricated conductor pattern using a prefabricated paste pattern, ink pattern or powder pattern
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B30PRESSES
    • B30BPRESSES IN GENERAL
    • B30B15/00Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/02Dies; Inserts therefor; Mounting thereof; Moulds
    • B30B15/022Moulds for compacting material in powder, granular of pasta form
    • B30B15/024Moulds for compacting material in powder, granular of pasta form using elastic mould parts
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B30PRESSES
    • B30BPRESSES IN GENERAL
    • B30B15/00Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/06Platens or press rams
    • B30B15/061Cushion plates
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/10Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the pressing technique, e.g. using action of vacuum or fluid pressure
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/14Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers
    • B32B37/26Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with at least one layer which influences the bonding during the lamination process, e.g. release layers or pressure equalising layers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00Ancillary operations in connection with laminating processes
    • B32B38/18Handling of layers or the laminate
    • B32B38/1825Handling of layers or the laminate characterised by the control or constructional features of devices for tensioning, stretching or registration
    • B32B38/1833Positioning, e.g. registration or centering
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29LINDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00Other particular articles
    • B29L2031/34Electrical apparatus, e.g. sparking plugs or parts thereof
    • B29L2031/3425Printed circuits
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/0284Details of three-dimensional rigid printed circuit boards
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/09Use of materials for the conductive, e.g. metallic pattern
    • H05K1/092Dispersed materials, e.g. conductive pastes or inks
    • H05K1/095Dispersed materials, e.g. conductive pastes or inks for polymer thick films, i.e. having a permanent organic polymeric binder
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/02Fillers; Particles; Fibers; Reinforcement materials
    • H05K2201/0275Fibers and reinforcement materials
    • H05K2201/0284Paper, e.g. as reinforcement
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09Shape and layout
    • H05K2201/09009Substrate related
    • H05K2201/09118Moulded substrate
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/06Lamination
    • H05K2203/068Features of the lamination press or of the lamination process, e.g. using special separator sheets
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00Apparatus or processes for manufacturing printed circuits
    • H05K3/38Improvement of the adhesion between the insulating substrate and the metal
    • H05K3/386Improvement of the adhesion between the insulating substrate and the metal by the use of an organic polymeric bonding layer, e.g. adhesive

Abstract

This invention relates to an apparatus and a process for uniformly laminating a conductor (18) to a substrate (15). The conductor can be a printed circuit; the substrate can be any dielectric. The apparatus comprises two platens (10, 11) containing cavities (12, 13). One of the cavities (13) contains a mold (14) which is the mirror image of a substrate surface. The other cavity (12) substantially contains the substrate (15). It can have two-dimensional or three-dimensional surfaces to which the printed circuit is laminated. The product results in a superior lamination of the printed circuit across the surface of the substrate.

Description

APPARATUS AND METHOD FOR FABRICATING PRINTED CIRCUIT BOARDS

Related Applications

This application is a continuation-in-part of Application Serial No. 214,380, filed July 1, 1988 entitled "Solderable Printed Circuits Formed Without Plating". The applications are commonly assigned. The parent application is incorporated by reference. Field of the Invention The present invention relates to a method and apparatus for transmitting uniformly applied pressure to a patterned release media to obtain a composite having a conductor, graphics and/or coating uniformly bonded to a substrate. This invention particularly relates to formation of a printed circuit board. Background of the Invention

The art area has been directed to forming circuit boards by techniques other than transferring a conductor to a substrate used to form the circuit board. The art area has been concerned principally with lamination of multilayered circuit boards.

For example. United States Patent No. 4,029,845 relates to a thermosetting resin in which heat and pressure are used to form a composite circuit board. The reference only discloses forming the base board and does not teach forming printed circuit elements on that baseboard. The reference refers to an additive process for manufacturing a printed circuit board without explanation of that teaching. United States Patent No. 4,180,608 teaches heat and pressure used to form a composite printed circuit board. However, the reference uses a carrier layer for resin but not a printed circuit as in the present invention. A lamination is formed as taught in the art.

As examples of methods and apparatus for molding structural parts, U.S. Patent No. 4,148,597 teaches an apparatus comprising a rigid container, pads of silicone rubber in the container used to exert pressure on the part to be formed and an expandable diaphragm which controls the pressure exerted on the part to be molded. The patent teaches such a method and apparatus useful to form complex-shaped parts from fiber reinforced plastic composite material.

U.S. Patent No. 4,243,368 also teaches a method and apparatus for making plastic articles from plastic particles utilizing heat and pressure applied using a flexible diaphragm to apply even fluid pressure. In operation, a layer of plastic particles is spread to a depth substantially equal to or slightly greater than that of a cavity formed on top of a platen. An air release means, which can be a wire cloth or screen, is located over the particles during compression.

U.S. Patent No. 4,670,084 teaches an apparatus for applying decorative images to members wherein sheets containing the images are overlaid on the members and maintained in pressurized engagement while the sheets* and the members are- heated. Vacuum is used to maintain the pressurized engagement.

U.S. Patent No. 4,636,275 teaches an integrated circuit package fabricated by assembling a stack comprising a plurality of thin flat epoxy glass layers, adhesive layers between those layers and a cavity. A conductor is not being transferred to a substrate. The stack is covered with an elastic bladder and is laminated by forcing fluid into the bladder at a temperature and pressure which causes the bladder to push against the surfaces of the cavity. This dams the adhesive from flowing into the bonding pads.

The preceding references are all incorporated by reference.

This invention overcomes disadvantages found in the prior art which relates to laminating conductor to substrates, particularly those substrates which have complex shapes. Summary of the Invention

This invention relates to a uniform pressure transmitting apparatus for uniformly laminating a conductor to an at least two-dimensional substrate surface comprising (a) a first platen means having a first cavity means, the first cavity means substantially confining a mold which is a mirror image of the at least two-dimensional substrate surface, (b) a second platen means containing a second cavity means which substantially confines the thickness of the substrate, (c) pressurization means for compressing a conductor positioned on the substrate surface using the first platen means, and (d) laminating means to bond the conductor to the substrate surface.

This invention also relates to a uniform pressure transmitting apparatus for uniformly laminating a printed circuit to an at least two-dimensional substrate surface composed of a polyarylsulfone polymer comprising (a) a first platen means having a first cavity means, the first cavity means substantially confining a mold which is a mirror image of the at least two- dimensional substrate surface, (b) a second platen means containing a second cavity means dimensioned to confine a substantial portion of the thickness of the substrate composed of polyarylsulfone polymer, (c) pressurization means for compressing a printed circuit positioned on the substrate surface using the first cavity means, and (d) laminating means to bond the printed circuit to the substrate surface to form a circuit board.

This invention further relates to a method for uniformly laminating a conductor to an at least two- dimensional substrate surface comprising inserting a substantial portion of the thickness of the substrate in a cavity means of a platen means, positioning a conductor on the at least two-dimensional substrate surface, applying a uniform pressure to the conductor and the substrate surface using another platen means containing another cavity means which substantially confines a mold which is a mirror image of the at least two-dimensional substrate surface, and laminating the conductor to the substrate surface.

This invention also further relates to a method for uniformly laminating a printed circuit to an at least two-dimensional substrate surface comprising inserting a substantial portion of the thickness of a substrate composed of polyarylsulfone polymer in a cavity means of a platen means, positioning a printed circuit on the at least two-dimensional substrate surface, applying a uniform pressure to the positioned printed circuit and the substrate surface using another platen means containing another cavity means which substantially confines a mold which is a mirror image of the at least two-dimensional substrate surface, and laminating the printed circuit to the substrate surface to form a printed circuit. Brief Description of the Drawings

This invention will now be described using drawings which depict certain embodiments of the present invention. The drawings are exemplary only; they are not considered to limit the invention:

Fig. 1 shows a schematic depiction of the uniform pressure apparatus of the present invention;

Fig. 2 shows a printed circuit on a substrate; Figs. 3A and 3B show applicants' earlier press and transfer method with Fig. 3B further showing use of pins to obtain registration of conductor on the substrate;

Fig. 4 shows results of adhesion tests performed on a conductive surface adhered to a substrate prepared using the earlier press and method of Figs. 3A and 3B;

Fig. 5 shows the press and transfer method of this invention; and

Fig. 6 shows the results of adhesion tests performed on a composite prepared according to the press and method of Fig. 5. Detailed Description of the Invention

This invention relates to a method and apparatus for uniformly applying pressure to at least' one side of a substrate or circuit board to laminate a conductor or printed circuit on it. The conductor can include a circuit alone or combined with other components, for example, adhesive, solder mask, graphics and/or transfer media. Laminating Conductor To Substrate

A release surface carrying at least a circuit covered by adhesive is contacted with a substrate such that the circuit is adjacent the substrate surface separated therefrom by adhesive. Sufficient heat and pressure are applied to form a composite structure, using the apparatus in Fig. 3 or Fig..5, whereby the adhesive is reacted. Thus, the circuit is transferred from the release surface and bonded to the substrate surface. In some cases, only partial curing and/or reaction need be obtained. The release surface is then separated from the composite structure.

The release surface and the substrate surface are contacted at a temperature of from about 100°C to about 230°C and preferably 140°C to 190°C. The surfaces are contacted at a pressure of from about 200 psi to about 1,200 psi and preferably 500 psi to 700 psi but not so great as to cause distortion of components. A pressure of 600 psi is preferred. Optionally, the substrate may be preheated to avoid distortion. Pressure can be applied for about 0.25 to 5 minutes, preferably 3 minutes.

In another embodiment, when the composite is formed, they are subjected to sufficient pressure during lamination to cause some compaction of the printed circuit. This causes further densification of the printed circuit, improving its conductive qualities. It has been noted that such compaction does not result in smearing of the electric circuit. Thus, the fine edges achieved in printing the electric circuit are maintained. Preferably, compaction of 25 to 40% of original printed electric pathway thickness is obtained. This invention overcomes many deficiencies in printed circuitry fabrication in terms of simplicity, ease of operation, functional utilization and performance. Substrate Surface The substrate may be any known dielectric, that is, insulating or non-conducting substrate. The related application referred to above provides a detailed list of suitable substrates which can be used in this invention. Suitable substrates include those fabricated from thermoset and thermoplastic materials and their mixtures. Preferred substrates will be taught below. They can have two or three dimensional surfaces. Thermoplastics, in general, exhibit a more complex range of chemical, thermal, and mechanical behavior than traditional thermoset printed circuit board laminates. This makes material selection for printed circuit uses even more critical. Current resin systems typically exhibit one or two desired characteristics but in general lack overall property balance to make them good printed circuit support candidates. Resin deficiencies become readily apparent during assembly operations where substrate warpage, bubbling, dimensional instability and printed circuit delamination are common occurrences.

To address this need, applicants use engineering resins called polyarylsulfone resins. These resins offer a highly desirable property balance for circuit board uses where excellent dimensional stability, warp resistance and bonding of circuit and substrate are requirements.

Polyarylsulfone resins are characterized by inherently high heat distortion temperatures, excellent dimensional stability, creep resistance, low loss AC dielectric properties, and high mechanical strength. Typical Properties of Polyarylsulfone Resins Property Units Typ¬ical Property Tensile Strength psi 13,400 Elongation to Break % 2.2 Tensile Modulus psi 892,000 Flexural Strength psi 19,300 Heat Deflection

Temperature °C 215 Density gm/cc 1.55 AC Dielectrics

Dielectric Constant 60 Hz 3.86 1 KHZ 3.85 Dissipation Factor 60 Hz 0.0042 1 KHZ 0.0035 Dielectric Strength 1/8" specimen Volts/mil 398-550 Volume resistivity at 50°C meg ohm-cm 0.41 x 10-*-•■- Injection Molding Polyarylsulfone resins are easily processed utilizing standard injection molding machinery and practice. Prior to molding, resins should be dried to obtain optimum performance in a dehumidified hopper drier or circulating air oven. Utilization of a hopper drier is preferred with an inlet air temperature in the 149- 163°C range and an outlet temperature not less than 135°C. When tray drying is utilized, pellets should be spread into a layer 1-2" in depth. It is important in all cases that the pellets reach and maintain a minimum temperature of 135°C for 3-4 hours. Dried resin should be molded promptly and handled carefully to preclude moisture reabsorption. The rheological characteristics of polyarylsulfone resins provide excellent flow for filling thin and intricate wall sections typically encountered in printed wiring boards, chip carriers, and related devices. The resins process readily at stock temperatures in the 360-382°C ranges (wave soldering grade). Mold temperatures of 110-157°C are used typically with the resin for wave solderable moldings. Clean polyarylsulfone resin scrap may be reground and utilized in fabrication, provided it is properly dried and kept free of contamination.

Polyarylsulfone produces warp-free moldings that are dimensionally stable both prior to and following the transfer process. Transferred circuitry exhibits tenacious adhesion to the resin as transferred, .and maintains its adhesion following wave soldering.

Additives which may be used with the thermoplastic and/or thermosetting resin for making the printed circuit board, include reinforcing and/or non- reinforcing fillers such as wollastonite, asbestos, talc, alumina, clay, mica, glass beads, fumed silica, gypsum and the like; and reinforcement fibers such as aramid, boron, carbon, graphite, and glass. Glass fiber is the most widely used reinforcement in the form of chopped or milled strands, ribbon, yarn, filaments, or woven mats. Mixtures of reinforcing and non-reinforcing fillers may be used, such as a mixture of glass fibers and talc or wollastonite. These reinforcing agents are used in amounts of from about 10 to about 80 weight percent, whereas the non-reinforcing fillers are used in amounts of up to 50 weight percent. Other additives include stabilizers, pigments, flame retardants, plasticizers, processing aids, coupling agents, lubricants, mold release agents, and the like. These additives are used in amounts which achieve the desired result.

Polyarylsulfone Polyarylsulfone is the preferred thermoplastic polymer substrate of the invention. It is an amorphous thermoplastic polymer containing units of the formula:

Figure imgf000012_0001

wherein R55 is independently hydrogen, C-_ to Cg alkyl to C4 to C8 cycloalkyl, X' is independently R56

C I

R57 wherein Rζζ and R57 are independently hydrogen or Ci to Cg alkyl, or

Figure imgf000012_0002

R59 wherein R58 and R59 are independently hydrogen or Ci to Cg alkyl, and a-[ is an integer of 3 to 8; -S-, -0-, or -fH+, a is an integer of 0 to 4 and n is independently an integer of 1 to 3 and wherein the ratio of unit (I) to the sum of units (II) and/or (III) is greater than 1. The units are attached to each other by an -0- bond.

A preferred polymer of this invention contains units of the formula:

Figure imgf000013_0001

Another preferred polyarylsulfone of this invention contains units of the formula:

Figure imgf000013_0002

These units are attached to each other by an -0- bond.- The polyarylsulfone may be random or may have an ordered structure. The polyarylsulfones of this invention have a reduced viscosity of from about 0.4 to greater than 2.5, as measured in N-methylpyrolidone, or other suitable solvent, at 25°C.

Laminating Apparatus Fig. 1 shows an apparatus for uniformly applying pressure to laminate a conductor or printed circuit to a substrate. The apparatus comprises heated platens 10 and 11, which may be differently disposed. Each of the platens has a cavity 12 and 13, respectively. The platens are heated in a conventional manner which is not shown. Platen 11 contains a mold 14 which is confined in the cavity 13. Mold 14 can be made of silicone rubber and is the mirror image of substrate 15 located in cavity 12 in platen 10. The mold can be made of other conventional high temperature elastomeric materials known in the art. The exposed surface of mold 14 preferably lies in the plane of the exposed surface of platen 11. The mold and substrate can be retained in their respective cavities using any conventional means. The surface of the substrate 15 can be two or three dimensional.

The mold is located so that during compression, movement lateral to the normal direction of compression of the platens is avoided to the extent that uniform pressure is applied across the surface of the substrate, that is, the mold is substantially confined. A portion of the substrate should project beyond the upper surface of platen 10 to facilitate uniform transfer and to compensate for any misalignment of platens. Only as much of board as necessary need project so that the board cannot distort or move laterally during compression. Thus the cavity substantially confines the board.

Also shown, are registration pins 16 and attendant openings on the opposing platen which facili¬ tate aligning the opposing or upper mold with the sub- strate 15. Conventional pressurization means which cause platen movement and compression is used but not shown. In operation, the platens are spread apart with the platen 11 containing the' silicone rubber mold 14. A plastic substrate 15 is inserted into cavity 12 in platen 10. Thereafter a release or transfer paper 17, carrying a printed circuit and adhesive, is placed over the substrate 15. Conventional pressurization means causes at least one platen to move toward the other. The alignment of the platens is facilitated utilizing registration pins 16 on one platen which mates with a complementary apature on the opposing platen. Lamination occurs at conventional temperatures and pressures by heating the platens utilizing conventional heating means (not shown). Thereafter, the printed circuit, which is completely or partially laminated to the substrate, is removed as a product and the release or transfer paper removed.

The basic components carried by the release or transfer medium or paper are the conductor and adhesive. There are preferably more components. They include in the order applied to the release paper before transfer: graphics or legending, solder mask, printed circuit and adhesive. The first-mentioned component is informational or educational legends for the circuit board. This transfer medium facilitates manufacture of the circuit board in an expeditious manner. However, one or more components can be applied to the circuit board separately. For example, the legending can be applied directly to the board or multiple transfers of circuits can be done to the same circuit board. This apparatus has the advantage of uniformly applying pressure across the entire surface of the substrate, whether it is two-dimensional or three- dimensional in shape. That is, the surface upon which 14

the printed circuit is applied can be flat or three- dimensional. The confinement of the silicone rubber mold 14 in the cavity 13 restricts movement of the mold in the cavity and is a factor in promoting the uniform pressure 5 and superior lamination of the printed circuit across the surface of the substrate. The cavity 12 further promotes the uniform application of pressure because the substrate is substantially confined in the cavity 12 which precludes its movement, especially laterial

10 movement, and distortion of the upper surface of the substrate when pressure is applied to its upper surface. These cavities are critical to obtain the superior lamination of printed circuit to substrate and overcomes earlier disadvantages.

15 Intended Use

The transfer of circuitry can be made to take place over planar or three-dimensional substrates to the extent the surface is "developable". For example, a three-dimensional circuit can be transferred to an

20. injection molded substrate.

Uses for the process are aimed at such three- dimensional type devices in high volume where the speed of the printing process for the circuit and the efficiency of the use of injection molded substrate can

25 be utilized cost-effectively.

Specifically, planar or shallow three- dimensional circuit boards can be efficiently produced using the process. Also, with some process modification, a series of molded plastic chip carriers can be tooled

30 and produced. These plastic chip carriers utilize a pre- molded thermoplastic substrate and a transfer process to apply the conductors, which are subsequently plated, to accomodate wire bonding and soldering operations. These chip carriers are manufactured from the same resin system that is used in the circuit boards; and when they are used together, there is no thermal mismatch between the chip carrier and the circuit board. An automotive use includes molding a circuitry to the inside roof portion of an automobile having dome light circuitry.

Examples The invention will now be described with examples of the teachings set forth above. These examples are exemplary and not exclusive. They are not considered limiting. Concentrations are percent by weight unless otherwise indicated.

Example 1 The following ingredients in percent by weight are blended together at room temperature:

(I) 1.81 percent polyhydroxyether known as Phenoxy PKFE, (II) 2.75 percent 3,4 epoxy cyclohexyl methyl 3,4 epoxy cyclohexyl carboxylate known as epoxy

ERL-4221, and (III) 8.47 percent diethylene glycol monobutyl ether acetate known as butyl Carbitol acetate. To this mixture is added the following ingredients:

(IV) 82.62 percent of silver powder from Metz

Metallurgical Co. known as METZ EG200ED; and (V) 4.35 percent of silver flake also from Metz Metallurgical Co. known as METZ 50S. More particularly, the phenoxy resin is dissolved in diethylene glycol monobutyl ether acetate with agitation. The epoxy resin is added to this mixture while agitation is continued. Then, silver powder is added to the mixture under continued agitation until it is dispersed to a Hegman grind of six. Then, the silver flake is added until it is also dispersed to a grind of six or better. The viscosity of the mixture is 35,000 cps as determined with a Brooksfield RVT Viscometer at 24°C using a number six spindle at 20rpm. The 2.5/20rpm viscosity ratio is 4. The conductive metal and binder are mixed together until completely homogenized to form an ink. This conductive ink is screen printed (U.S.

Sieve size 230), using conventional techniques, onto VNS Supermat release paper (obtained from S.D. Warren Co., Westbrook, Maine) to a thickness of approximately 1 mil after drying. The printed paper is dried in a forced convection oven at 96°C for ten minutes.

Separately, an adhesive containing the following ingredients is prepared:

TRADE NAME CHEMICAL NAME NEW (WT.%

PHENOXY PKFE POLYHYDROXY ETHER 18.99

RESIMENE 2040 MELAMINE FORMALDEHYDE 0.95

BUTYL CARBITOL DIETHYLENE GLYCOL MONO 75.96

ACETATE BUTYL ETHER ACETATE

BLACK SAPL NIGROSINE BLACK 0.19

BENZOIC ACID BENZOIC ACID 0.05

CABOSIL SILICA 3.86 Making The Adhesive

The polyhydroxyether or phenoxy resin is dissolved in the diethylene glycol monobutyl ether acetate using high speed mixing until all the resin particles are dissolved. The melamine formaldehyde resin is then added. The nigrosine black and benzoic acid are mixed together and then added with high shear agitation. The high surface area silica is then added with high shear mixing. The entrained air is removed with vacuum. The viscosity of the adhesive composition measured with an RVT Viscometer at 24°C using a number six spindle at 20 rpm is 35,000 cps with a 2.5/20rpm viscosity ratio of 4. The prepared adhesive is screen printed in registration on top of the conductor surface of the printed circuit which is already dried. Then, the adhesive coated circuit is placed in a forced convection oven at 96°C for 10 minutes until the adhesive coat is dry but not fully cured.

A substrate is molded from a composition containing 78 weight percent of a polymer containing the following unit:

Figure imgf000019_0001

having a reduced viscosity of 0.61 dl/g as measured in N- methyl-pyrrolidinone (0.2 g/100 ml) at 25°C. The composi¬ tion also contains 12 weight percent mica and 10 weight percent of chopped glass fibers obtained from Owens Corning.

The substrate composition is injection molded using conventional conditions. A 6 in. x 6 in. plaque which is 0.06 in. thick is molded. The melt temperature is 377°C, and the mold temperature is 151°C. The injection speed is 35mm/sec, and the injection molding pressure is 100 bars for 7 sec. The substrate sheet is vapor polished with methylene chloride for about one second.

The substrate is placed in a compression platen press as shown in Figures 3 and 5 with the release paper containing the conductor (1.0-1.2 mils dry film thickness) and the adhesive printed in the registration (0.6-0.8 mils dry film thickness). Then it is molded at 600 psi for 3 minutes at 177°C after the release paper is stripped away. The circuit board is then cured in an oven at 150°C for 30 minutes. After cure, the board can be soldered with a hand soldering iron or in a wave solder machine set at 246°C with a carrier speed of 6 ft/min. The electrical resistance of a square serpentine pattern was measured with a milliohm meter. Consistent values in the range of 5-10 milliohms/mil square are obtained.

Comparative tests are conducted using an earlier press shown in Figures 3A and 3B and a press according to the teachings of this invention shown in Figure 5. In each test, a substrate having a two-dimensional surface is placed on or in a platen. The thickness which protrudes is 20 mils. The release or transfer paper with printed circuit and adhesive components is placed on it. The board and transfer medium are compressed by closing the platens. Lamination is achieved using a pressure of 600 psi, a temperature of 177°C and a time of three minutes. Then, the release paper is removed, and the circuitized substrate is cured at 150°C for thirty minutes. After cure, the board can be soldered with a hand soldering iron or in a wave solder machine set at 246°C with a carrier speed of 6 ft/mm. For bond strength determination, copper wires

(.05/inch diameter) are soldered onto 1/4 inch diameter pads of the circuit board. After cooling, the wires are pulled from the boards clamped onto the base of a Chatillon tensile tester Model UTSM. The wires are hooked onto the end of a AMETEK ACCU Force Gage II. The circuit board is then lowered at the #1 setting of the Chattilon tester, and the maximum force is measured to break the bond between the wire and the 1/4 inch pad on a 1/16 inch substrate board. The sample obtained using the prior art press showed the non-uniform adhesion test results of Figure 4. Those obtained using the process of this invention showed the uniform results of Figure 6. Figure 4 shows an average tensile strength of 25.06 lbs. or in other words 510.4 psi with 13% of the failures in the substrate. However, Figure 6 shows an average tensile strength 48.1 lbs. or 980.6 psi with 91% of failures in the substrate.

While these results are very impressive, each figure shows the test results at different locations on a circuit board like that of Figure 2. Each of the sixteen circuits were tested. The tensile strength measurement for the adhesion bond of each circuit is shown with the bond strength determination for the soldered wire shown in the upper right hand corner. Failures are designated ιιpi. or ngii to indicate plug (plastic board) or snap (circuit interface) failures, respectively. In Figure 4, the earlier technique shows the least bond strength about the perimeter of the circuit board. However, Figure 5 according to this invention shows superior, uniform bond strength all over the circuit board compared to the results of Figure 4 tests. Example 2

Example 1 is repeated except that both sides of the circuit board are laminated with a printed circuit. Example 3 Example 1 is repeated except that the surface of the circuit board upon which circuitry is applied is three dimensional. Although the invention has been described in conjunction with specific embodiments, it is evident that many alternatives and variations will be apparent to those skilled in the art in light of the foregoing description. This may include optionally plating the printed circuit even though the circuit is solderable without this treatment. This may also include reversing the platen arrangement so that the substrate is above the platen housing the mold. Also the alignment pins can be attached to either platen. Further, both sides of the substrate may be processed. Accordingly, the invention is intended to embrace all of the alternatives and variations that fall within the spirit and scope of the appended claims.

Claims

1. A uniform pressure transmitting apparatus for uniformly laminating a conductor to an at least two- dimensional substrate surface comprising (a) a first platen means having a first cavity means, the first cavity means substantially confining a mold which is a mirror image of the at least two-dimensional substrate surface, (b) a second platen means containing a second cavity means which substantially confines the thickness of the substrate, (c) pressurization means for compressing a conductor positioned on the substrate surface using the first platen means, and (d) laminating means to bond the conductor to the substrate surface. . The apparatus according to claim 1, wherein the substrate is three-dimensional.
3. The apparatus according to claim 1, wherein the mold is a silicone rubber mold.
4. The apparatus according to claim 1, wherein the substrate is plastic. 5. The apparatus according to claim 4, wherein the plastic is a thermosplastic.
6. The apparatus according to claim 4, wherein the plastic is a polyarylsulfone polymer.
7. The apparatus according to claim 1, wherein a platen contains registration pins.
8. The apparatus according to claim 7, wherein the first platen contains registration pins.
9. The apparatus of claim 1, wherein the conductor is a printed circuit. 10. A uniform pressure transmitting apparatus for uniformly laminating a printed circuit to an at least two-dimensional substrate surface composed of a polyarylsulfone polymer comprising (a) a first platen means having a first cavity means, the first cavity means substantially confining a mold which is a mirror image of the at least two-dimensional substrate surface, (b) a second platen means containing a second cavity means dimensioned to confine a substantial portion of the thickness of the substrate composed of polyarylsulfone polymer, (c) pressurization means for compressing a printed circuit positioned on the substrate surface using the first cavity means, and (d) laminating means to bond the printed circuit to the substrate surface to form a circuit board.
11. A method for uniformly laminating a conductor to an at least two-dimensional substrate surface comprising inserting a substantial portion of the thickness of the substrate in a cavity means of a platen means, positioning a conductor on the at least two- dimensional substrate surface, applying a uniform pressure to the conductor and the substrate surface using another platen means containing another cavity means which substantially confines a mold which is a mirror image of the at least two-dimensional substrate surface, and laminating the conductor to the substrate surface.
12. The process according to claim 11, wherein the substrate surface is three-dimensional. 13. The method according to claim 11, further comprising laminating utilizing a conventional heating source.
14. The method according to claim 11, wherein the mold is a silicone rubber mold. 15. The method according to claim 11, wherein the substrate is plastic.
16. The method according to claim 15, wherein the plastic is a thermoplastic. 17. The method according to claim 15, wherein the plastic is a polyarylsulfone polymer.
18. The method according to claim 11, wherein one of the platens contains registration pins. 19. The method according to claim 11, wherein the substrate is preheated.
20. The method according to claim 11, wherein the conductor is a printed circuit.
21. The method according to claim 11, wherein lamination occurs between 100°C and 230°C.
22. The method according to claim 21, wherein lamination occurs between 140°C and 190°C.
23. The method according to claim 11, wherein the pressure is between 500 psi and 700 psi. 24. A method for uniformly laminating a printed circuit to an at least two-dimensional substrate surface comprising inserting a substantial portion of the thickness of a substrate composed of polyarylsulfone polymer in a cavity means of a platen means, positioning a printed circuit on the at least two-dimensional substrate surface, applying a uniform pressure to the positioned printed circuit and the substrate surface using another platen means containing another cavity means which substantially confines a mold which is a mirror image of the at least two-dimensional substrate surface, and laminating the printed circuit to the substrate surface to form a printed circuit.
PCT/US1990/002139 1989-04-27 1990-04-17 Apparatus and method for fabricating printed circuit boards WO1990012668A1 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5879502A (en) * 1994-05-27 1999-03-09 Gustafson; Ake Method for making an electronic module and electronic module obtained according to the method
EP1334820A2 (en) * 2002-02-07 2003-08-13 W.C. Heraeus GmbH & Co. KG Punch for a laminating press and use
WO2007009510A1 (en) * 2005-07-21 2007-01-25 Hirschmann Car Communication Gmbh Method for applying electrical conductor patterns to a target component of plastic

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1806861A (en) * 1931-05-26 Apparatus for making composite glass
US2519661A (en) * 1948-02-14 1950-08-22 Onondaga Pottery Company Apparatus for fixing transfers
US3783073A (en) * 1971-05-19 1974-01-01 A Warnberg Method for transferring indicia to fabrics
US3940534A (en) * 1973-11-07 1976-02-24 G. T. Schjeldahl Company Electrical laminate
US4110139A (en) * 1974-03-13 1978-08-29 Nco Works Ltd. Process for preparing bands or belts, particularly suitable for use as watch bands
US4564408A (en) * 1983-05-25 1986-01-14 Saint-Gobain Vitrage Process and device for covering a lens preform with a protective sheet
US4594311A (en) * 1984-10-29 1986-06-10 Kollmorgen Technologies Corporation Process for the photoselective metallization on non-conductive plastic base materials
US4702787A (en) * 1983-06-10 1987-10-27 Agrifim Irrigation International Nv Process for making drip irrigation lines

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1806861A (en) * 1931-05-26 Apparatus for making composite glass
US2519661A (en) * 1948-02-14 1950-08-22 Onondaga Pottery Company Apparatus for fixing transfers
US3783073A (en) * 1971-05-19 1974-01-01 A Warnberg Method for transferring indicia to fabrics
US3940534A (en) * 1973-11-07 1976-02-24 G. T. Schjeldahl Company Electrical laminate
US4110139A (en) * 1974-03-13 1978-08-29 Nco Works Ltd. Process for preparing bands or belts, particularly suitable for use as watch bands
US4564408A (en) * 1983-05-25 1986-01-14 Saint-Gobain Vitrage Process and device for covering a lens preform with a protective sheet
US4702787A (en) * 1983-06-10 1987-10-27 Agrifim Irrigation International Nv Process for making drip irrigation lines
US4594311A (en) * 1984-10-29 1986-06-10 Kollmorgen Technologies Corporation Process for the photoselective metallization on non-conductive plastic base materials

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5879502A (en) * 1994-05-27 1999-03-09 Gustafson; Ake Method for making an electronic module and electronic module obtained according to the method
EP1334820A2 (en) * 2002-02-07 2003-08-13 W.C. Heraeus GmbH & Co. KG Punch for a laminating press and use
EP1334820A3 (en) * 2002-02-07 2005-04-13 W.C. Heraeus GmbH Punch for a laminating press and use
WO2007009510A1 (en) * 2005-07-21 2007-01-25 Hirschmann Car Communication Gmbh Method for applying electrical conductor patterns to a target component of plastic

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CA2031488A1 (en) 1990-10-28
JPH03506003A (en) 1991-12-26

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