TW201339241A - Polymer composition for microelectronic assembly - Google Patents

Abstract

Embodiments in accordance with the present invention encompass polymer compositions that are useful in the assembly of microelectronic components onto a variety of substrate materials. Such polymer compositions providing for both holding the microelectronic components at desired positions on a substrate, providing fluxing for the solder bonding of such components to the substrate and remaining in place as an underfill for such components.

Description

Polymer composition for microelectronic components

The present application is hereby incorporated by reference to U.S. Provisional Serial No. 61/416,508, entitled "Polymer Composition for Microelectronic Assembly", filed on November 23, 2010. This provisional patent is hereby incorporated by reference in its entirety.

Embodiments in accordance with the present invention generally relate to polymer compositions that are useful for mounting microelectronic components to a substrate, and more particularly to securing microelectronic components on a substrate at a desired location, providing assistance for soldering the component to the substrate. Melt and maintain the original position as the polymer composition of the underfill for this component.

When the assembled electronic circuit has been dramatically reduced in size, the use of soldering as a method of attaching electronic components to the substrate electrically and fixedly is still quite popular. However, this attachment must maintain the various components in the desired position prior to completion of the solder attachment described above, as well as the post-electric underfill connection. The underfill connection extends the thermal fatigue of the solder ball connection, protects the connection environmentally, and provides better mechanical shock and stability to the assembled electronic circuit.

A number of solutions have been successfully developed and used to maintain the components in their desired position. For example, when soldering or solder ball bonding is applied while heat is applied, the component can be temporarily fixed to the substrate using an adhesive. After this temporary connection is completed, the adhesive will remain as a contaminant/residue, so the assembly should accept additional processing steps designed to remove this contamination. For some of the above solutions, in addition to the adhesive, the flux is separately provided, for example The flux is applied as in a separate coating step than the coating of the adhesive. Other solutions provide a fluxing agent for the combination of adhesives, such as the use of solder paste as an adhesive and the addition or prior reaction of the flux.

In other solutions, (see U.S. Patent No. 5,177,134 or U.S. Patent Application Serial No. 2009/0294515, the '134 patent and the '515 application, respectively, incorporates an adhesive and a flux during welding). The adhesive vaporizes or decomposes. However, it has been found that the adhesive is vaporized or decomposed at or above the solder reflow temperature. As each of the above teachings, any solder reflow is limited, and a large amount of contamination from the adhesive may remain or require special Processing equipment.

Thus a new solution can provide a single material that maintains the component in the desired position prior to completion of solder attachment (eg, as an adhesive), providing any desired fluxing (eg, performance as a co-solvent) and also It is desirable to provide a post-electric underfill connection. Still further, it would be advantageous if the solution could eliminate the need for this particular device, as described above, and reduce or eliminate the problem of obtaining the desired solder reflow and/or any contamination associated with its results.

Specific embodiments in accordance with the present invention are disclosed below with reference to the embodiments and claims. Various modifications, adaptations, and variations of the exemplary embodiments disclosed herein will be apparent to those skilled in the art. It is to be understood that all such modifications, adaptations, and variations of the present invention are intended to be within the scope and spirit of the invention.

Used here, the number "one ("a", "an")" and "the" (the ")" The term includes plural referents unless otherwise explicitly and directly limited to one reference.

As used herein, the term ""group" or "groups") when used in reference to a chemical compound and/or chemical structure/chemical formula, means an arrangement of one or more atoms.

Used herein, the molecular weight of the polymer, such as a weight average molecular weight (M _w) and number average molecular weight (M _n), by gel permeation chromatography-based technique measured using polystyrene standards.

As used herein in the polydispersity index (PDI) represented by the value-based polymer of weight average molecular weight (M _w) ratio of the number average molecular weight (M _n) (i.e. M _w / M _n).

As used herein, unless otherwise indicated, the polymer glass transition temperature ( _Tg ) value is determined by the differential scanning thermal method according to ASTM method number D3418.

As used herein, unless otherwise indicated, the polymer decomposition temperature (T _d ) is the temperature determined by thermogravimetric analysis at a heating rate of 10 ° C / min, and the specific weight percentage (wt %) of the polymer needs to be decomposed. And measured. The terms T _d5 , T _d50 and T _d95 refer to temperatures which have been decomposed at 5 wt%, 50 wt% and 95 wt%.

All ranges or ratios disclosed herein are to be understood to include any and all sub-ranges or sub-ratio. For example, the range or ratio "1 to 10" shall be taken to include any and all sub-ranges between (from and including) the minimum value 1 to the maximum value 10; Minimum 1 starts or more to maximum 10 ends or less, such as but not limited to, 1 to 6.1, 3.5 To 7.8, and 5.5 to 10.

In the working examples, and unless otherwise indicated, all numbers used in the specification and the scope of the claims, the contents of the ingredients, the conditions of the reaction, etc., should be understood in all the examples. To determine the various uncertainties of these values.

Polymers, such as poly(propylene carbonate), are well known, and the '134 patents and the '515 application teach the use of such polymers as effective adhesives. However, the poly(propylene carbonate) is also widely known to be thermally decomposed under the temperature range of 200 ° C to 280 ° C, and in which the material is expected to be used as an adhesive, a flux and an underfill. Therefore, there may be doubts. This is particularly true when a lead-free solder is used to make solder interconnects because the lead-free solder typically has a melting point range of 30 to 40 ° C above the lead-containing solder used in general. For example, in the case of Sn99.3Cu0.7, the Sn60Pb40 solder alloy generally used has a melting point range of 183 to 190 ° C and is used in the following examples, and has a melting point of 227 ° C.

Some polymer embodiments in accordance with the present invention include polymers formed from stereospecific norcanediol and/or dimethanol monomers, while other polymer embodiments are derived from suitable alkyl carbonates. An ester monomer and the aforementioned norbornanediol and/or dimethanol monomer. Beneficially, some such polymer embodiments have a _Td50 greater than 280 °C, while other such polymer embodiments have a _Td50 greater than 310 °C, and still other such polymer embodiments have a T greater than 340 °C _D50 . In addition, some of the norbornanediol and/or dimethanol systems thus containing a specific embodiment of the polymer have a molecular weight (M _w ) ranging from 5,000 to 300,000, and in another embodiment, a M _w of from 25,000 to 200,000, and Still other such embodiments are 40,000 to 185,000.

Some of the aforementioned stereospecific norbornanediol and/or dimethanol monosystems are represented by or are selected from the following chemical formulas A, B or C:

Wherein, for each of the chemical formulas A, B and C, n is independently 0, 1 or 2, and each of R ¹ , R ² , R ³ and R ⁴ is independently selected from hydrogen or contains, but is not limited to, 1 to 25 a hydrocarbon group of one carbon atom; each of R ⁵ and R ⁶ is independently selected from -(CH ₂ ) _p -OH, wherein p is 0, 1, 2 or 3, and each X and X' is independently selected from -CH ₂ -, -CH ₂ -CH ₂ - and -O-, wherein X', if present, is oriented in the same or opposite direction as X. For some embodiments in accordance with the invention, at least one of R ⁵ and R ⁶ is p, 1, 2 or 3.

The term "hydrocarbyl" as used herein, and similar terms, such as "hydrocarbon group", mean carbon containing carbon and, as the case may be, non-limiting examples of which are alkyl, cycloalkyl, polycycloalkyl, aryl. a group of an aralkyl group, an alkylaryl group, an alkenyl group, a cycloalkenyl group, a polycycloalkenyl group, an alkynyl group, a cycloalkynyl group, and a polycycloalkynyl group Free radicals. The term "halogenated hydrocarbon group" as used herein means a hydrocarbon group which is covalently bonded to at least one hydrogen of one carbon by one halogen. The term "perhalocarbyl" as used herein means a hydrocarbon group in which all of the hydrogen is replaced by a halogen. Also, as used herein, the term "heterohydrocarbyl" means a hydrocarbon radical wherein at least one carbon atom is replaced by a heteroatom such as oxygen, nitrogen and/or sulfur.

As used herein in the term "alkyl" means a linear or branched acyclic or cyclic from a C ₁ to C ₂₅ carbon chain length of the saturated hydrocarbon. Non-limiting examples of suitable alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, second butyl, tert-butyl, pentyl, neopentyl, hexyl, g. Base, octyl, decyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl , nonadecyl, isocanyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl. As used herein, the term "heterocycloalkyl" means a cycloalkyl group wherein one or more of the carbons of the cyclic ring are substituted with a heteroatom such as oxygen, nitrogen and/or sulfur. Representative heterocycloalkyl groups include, but are not limited to, tetrahydrofuranyl, tetrahydropyranyl, Alkyl and piperidinyl.

As used herein, the term "aryl" is intended to include, but is not limited to, phenyl, biphenyl, benzyl, xylyl, naphthyl, anthracenyl aromatic groups. As used herein, the term "heteroaryl" means that the carbon of one or more of the aromatic rings is replaced by a heteroatom, and the heteroaryl group of the aryl group such as oxygen, nitrogen and/or sulfur includes but not It is limited to furyl, piperanyl and pyridyl.

The use of the terms herein, "alkaryl" aryl group "lines may be interchanged, and means a linear or branched non-cyclic with at least one substituent of the aryl group, e.g., phenyl, and having a C ₁ to C ₂₅ carbon chain length of the alkyl group it should further be appreciated that the above-described non-cyclic alkyl or halogenated alkyl groups may be perhalogenated alkyl group.

As used herein, the term "alkenyl" means a hydrocarbon radical which is linear or branched acyclic or cyclic, having one or more double bonds and having an alkenyl group of C ₂ to C ₂₅ carbon bond length. Non-limiting examples of alkenyl groups include, among others, vinyl, allyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decene , undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecyl, hexadecenyl, heptadecenyl, octadecyl, pentadecenyl, hexadecene Isocenyl.

As used herein in the term "alkynyl" means a linear or branched acyclic or cyclic hydrocarbon group having one or more carbon triple bond and having C ₂ to C ₂₅ alkynyl group of key length. Representative alkynyl groups include, among others, ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, pentynyl, heptynyl, octyne Base, decynyl, decynyl, undecynyl, dodecynyl, tridecynyl, tetradecynyl, pentadecynyl, hexadecenyl, heptadecanyl, octadecynyl, Nineteen alkynyl, isocynyl.

As used herein, a reference to a "linear or branched" group, such as a linear or branched alkyl group, should be understood to include methylene, linear groups such as linear C ₂ -C ₂₅ alkyl, and suitable the branching groups, such as C ₃ -C ₂₅ branched alkyl.

For Chemical Formulas A, B, and C, the description of each X group will extend back from this page. Each of the descriptions of Chemical Formula A, R ⁵ and R ⁶ will extend rearward from this page, and such as, for example, cis- to corresponding and such as exo-relative to the X group. Chemical Formula A is therefore considered to be a polycyclic cis-exo 2,3-diol monomer. Each of the descriptions of Chemical Formula B, R ⁵ and R ⁶ will extend rearward from this page, and such as, for example, cis- to corresponding and such as internal-to-X groups. Chemical Formula B is therefore considered to be a polycyclic cis-internal 2,3-diol monomer. In the chemical formula C, the description of R ⁵ will extend backward from this page, and the outer-relative to the X group, the description of R ⁶ will extend backward from the page, the inner-relative to the X group, and the trans-relative to the corresponding . Chemical formula C is therefore considered to be a polycyclic inner/outer 2,3-diol monomer or a polycyclic trans 2,3-diol monomer.

For a further embodiment of the invention, for each of the chemical formulas A, B and C: n is 0; three of R ^{1 -} R ⁴ are hydrogen; and one of R ^{1 -} R ⁴ is independently selected from alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aryl, heteroaryl and aralkyl, and X is a relative system which is towards the outer (exo). To illustrate, when n = 0, X is -CH ₂ -, each of R ¹ , R ² and R ³ is hydrogen, R ⁴ is a non-hydrogen external group with respect to X, and each of R ⁵ and R ⁶ is -CH ₂ OH, Chemical Formulas A, B and C can be represented by the following chemical formulas A1, B1 and C1:

For each of Formulas A1, B1, and C1: R ⁴ may be selected from, for example, but not limited to, the hydrocarbyl groups of the foregoing classifications and examples herein, for example, see R ¹ -R ⁴ .

Other useful diol monomers include polycyclic diol monomers represented by the following chemical formulas D, E and F:

Independently, for each polycyclic diol monomer further represented by the following chemical formulas D, E and F: m system 0, 1 or 2; each Z and Z' system is independently selected from -CH ₂ - , -CH ₂ -CH ₂ - and -O-; Z ^* is -CH-; in each case R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are independently selected from hydrogen and hydrocarbyl; in each case R ¹¹ and R ¹² are independently selected from -(CH ₂ ) _p -OH, wherein in each of the examples, for R ¹¹ and R ¹² , the p is independently selected from 0, 1, 2 or 3; and each Z 'If present, they are oriented the same or opposite to the direction of Z or Z ^* , respectively.

For Chemical Formulas D, E, and F, the description of each Z group and Z ^* group will extend back from this page. In Formula D, if each Z' is present, each m has an independent orientation that is the same or opposite to the direction of Z. In Chemical Formulas E and F, if each Z' is present, each m has an independent orientation that is the same or opposite to the direction of Z ^* .

Each of the hydrocarbyl groups from R ^{7 to} R ¹⁰ may be independently selected from the group consisting of, but not limited to, the foregoing classifications and examples. For each of the formula DF, in a particular embodiment of the invention, at least one R ⁷ -R ¹⁰ is independently selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aryl, heteroaryl And a group of an aralkyl group, as well as other R ⁷ -R ¹⁰ groups, if any, are not selected from, for example, a non-hydrogen group, that is, hydrogen. Examples of each of the alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, aryl, heteroaryl and aralkyl groups from which R ⁷ -R ^{10 are} derived may be selected from, but not limited to, reference to R ^{1 -} R ^{4 are} listed in the foregoing classifications and examples.

In another embodiment, for each chemical formula DF: m is 0; three of R ^{7 -} R ¹⁰ are hydrogen; and one of R ^{7 -} R ¹⁰ is independently selected from alkyl, cycloalkyl, hetero alkyl, heterocycloalkyl, aryl, heteroaryl and arylalkyl, and which system relative to Z or Z ^* toward the outside. To illustrate, when m=0, Z is -CH ₂ -, each of R ⁷ , R ⁸ and R ⁹ is hydrogen, R ^{10 is a} non-hydrogen external group, and each of R ¹¹ and R ¹² is -CH for formula D. ₂ OH, and for the formulae E and F are -OH, the chemical formula DF can be represented by the following chemical formulas D1, E1 and F1. For further explanation, when m=0, Z is -CH ₂ -, each of R ⁸ , R ⁹ and R ¹⁰ is hydrogen, and R ^{7 is a} non-hydrogen external group, and each of R ¹¹ and R ^{12 is} for chemical formula D. -CH ₂ OH, and for the formulae E and F are -OH, the chemical formula DF can be represented by the following chemical formulas D1', E1' and F1'. It should be understood that all chemical formulae expressed herein include mirror images thereof and non-mirrored analogs, unless otherwise specified.

Still other diol monomers include polycyclic diol monomers represented by the following chemical formula G.

The polycyclic diol represented by the chemical formula G, each of Z, R ¹¹ and R ¹² is as described above with reference to the chemical formula EF.

Further diol monomers include the cyclic diol monomers represented by the following Chemical Formulas I to XII.

In Formulas X and XI, R ¹³ is independently selected from C ₁ -C ₆ alkyl such as, but not limited to, C ₁ -C ₆ linear alkyl or C ₃ -C ₆ alkyl.

Further optionally, the polyol monomer includes, but is not limited to, a hydrocarbon group having two or more hydroxyl groups such as, but not limited to, 2, 3 or 4 hydroxyl groups. Examples of selectively polyol monomers include, but are not limited to, C ₁ -C ₂₅ linear or branched alkenyl glycols such as 1,2-vinyl diol, 1,3-propenyl diol, and 1,2-propenyl glycol; and polyolefin-based glycols such as bis-, gin-, oxime- and higher glycols, bis-, gin-, oxime- and higher propylene glycols. The polyol monomer optionally having more than two hydroxyl groups is typically present in minor amounts such as, but not limited to, based on the total mole % of hydroxyl functional monomer, less than 10 mole percent, or less than 5 mole percent. Examples of polyol monomers having more than two hydroxyl groups include, but are not limited to, trimethylolpropane, neopentyl alcohol, and bis-trimethylolpropane. For certain embodiments, the polycarbonate polymer is not derived from a polyol monomer having more than two hydroxyl groups.

The polycyclic 2,3-diol monomers represented by Chemical Formulas A, B and C can be prepared by a general method, such as the synthetic schemes 1 to 6 shown below.

Non-limiting description: The polycyclic cis-exo 2,3-diol monomer represented by Chemical Formula A can be prepared according to the following Synthesis Scheme 1, wherein n is 0, and each R ¹ -R ⁴ is hydrogen. X-CH ₂ -, and each of R ⁵ and R ⁶ is -CH ₂ OH.

Synthesis flow chart 1

Referring to the synthesis scheme 1, endo-2,3-northene dicarboxylic anhydride (which may also be regarded as endo- nadic anhydride) (1a) is exposed to a temperature of 140 to 210 ° C for a sufficient period of time. Time, such as from 15 minutes to 24 hours after melting, followed by repeated recrystallization, such as two or more recrystallizations from ethyl acetate or toluene to form exo-2,3-nordecene dicarboxylic anhydride (Also considered as exo-nadic anhydride) (1b). Hydrogenation of cis-exo-nadic anhydride (1b) in the presence of hydrogen (H ₂ ), a palladium catalyst supported on porous carbon (Pd/C), and ethyl acetate (EtOAc) results in an external 2,3-norbornane dicarboxylic anhydride (1c). Reduction of exo-2,3-norbornane dicarboxylic anhydride (1c) in the presence of lithium aluminum hydride (LiAlH ₄ ) and diethyl ether (Et ₂ O), resulting in cis-exo-2,3-norbornane Dimethanol (A2).

Non-limiting description: Polycyclic cis-endo-2,3-diol monomer represented by Chemical Formula B can be prepared according to the following Synthesis Scheme 2, wherein n is 0, and each R ¹ -R ⁴ is hydrogen. X-CH ₂ -, and each of R ⁵ and R ⁶ is -CH ₂ OH.

Referring to the synthesis scheme 2, cis-endo-2,3-nordecene dicarboxylic anhydride (which may also be regarded as endo-nadic anhydride) (1a) is hydrogen (H ₂ ), a palladium catalyst supported on porous carbon. Hydrogenation in the presence of (Pd/C), and ethyl acetate (EtOAc) afforded the product <RTI ID=0.0>> Reduction of endo-2,3-norbornane dicarboxylic anhydride (2a) in the presence of lithium aluminum hydride (LiAlH ₄ ) and diethyl ether (Et ₂ O), resulting in cis-endo-2,3-norbornane Dimethanol (B2).

The polycyclic internal-external-2,3-diol monomer represented by Chemical Formula C can be prepared according to the following Synthesis Scheme 3, which is not intended to be a limitation, wherein n is 0, and each R ¹ -R ⁴ is hydrogen, X is -CH ₂ -, and each of R ⁵ and R ⁶ is -CH ₂ OH.

Referring to the synthesis scheme 3, cyclopentadiene (3a) and diethyl fumarate (3b) are reacted together at a low temperature by a Di-A reaction, such as 0 ° C, to form an inner-outer-2 , 3-northene bis(ethyl carbonate) (3c). Hydrogenation of endo-exo-2,3-northene bis(ethyl carbonate) (3c) in hydrogen (H ₂ ), palladium catalyst (Pd/C) supported on porous carbon, and ethyl acetate In the presence of (EtOAc), the result is an internal-exo-2,3-norbornane bis(ethyl carbonate) (3d). Reduction of endo-exo-2,3-norbornane bis(ethyl carbonate) (3d) in the presence of lithium aluminum hydride (LiAlH ₄ ) and diethyl ether (Et ₂ O), resulting in exo-endo-2 , 3-norbornane dimethanol (C2).

The polycyclic cis-exo-2,3-diol monomer represented by Chemical Formula A can be prepared according to the following Synthesis Scheme 4, which is not intended to be a limitation, wherein n is 0, and each R ¹ -R ⁴ is hydrogen, X is -CH ₂ -, and R ⁵ is -OH and R ⁶ is -CH ₂ OH.

Referring to the synthesis scheme 4, hexahydro-4H-5,8-extended methylbenzo[d]-exo-[1,3] The alkane (4a) is converted to cis-exo-(3-acetoxynorridin-2-yl)acetate in the presence of acetic anhydride (Ac ₂ O) and a catalytic amount of sulfuric acid (H ₂ SO ₄ ). Ester (4b) and cis-exo-((3-acetoxyoxin-2-yl)methoxy)acetic acid methyl ester (4c). The intermediates (4b) and (4c) are converted to cis-exo-3-(hydroxymethyl)nordecan-2-yl (A3) in the presence of water and a catalytic amount of sodium hydroxide (NaOH).

The polycyclic cis-endo-2,3-diol monomer represented by Chemical Formula B can be prepared according to the following Synthesis Scheme 5, which is not intended to be a limitation, wherein n is 0, and each R ¹ -R ⁴ is hydrogen, X is -CH ₂ -, and R ⁵ is -OH and R ⁶ is -CH ₂ OH.

Referring to the synthesis scheme 5, hexahydro-4H-5,8-methylbenzo[d]-endo-[1,3] The alkane (5a) is converted to cis-endo-(3-acetoxyoxen-2-yl)acetate in the presence of acetic anhydride (Ac ₂ O) and a catalytic amount of sulfuric acid (H ₂ SO ₄ ) Ester (5b) and methyl cis-endo-((3-ethyloximeoxypurin-2-yl)methoxy)acetate (5c). The intermediates (5b) and (5c) are converted to cis-endo-3-(hydroxymethyl)nordecan-2-yl (R3) in the presence of water and a catalytic amount of sodium hydroxide (NaOH).

The selective polycyclic diols represented by Chemical D, E, F and G can be prepared according to the general art. Non-limiting description: The selective polycyclic diol represented by Chemical Formula F can be prepared according to the following Synthesis Scheme 6, which is not intended to be a limitation, wherein m is 0, and each R ⁷ -R ¹⁰ is hydrogen, Z is -CH ₂ -, and R ¹¹ is -OH and R ¹² is -CH ₂ OH.

Referring to the synthesis scheme 6, 2,3-northene (6a) is converted to (2-(methyloxy) in the presence of formic acid (HCOOH), sulfuric acid (H ₂ SO ₄ ) and formaldehyde (H ₂ CO). ) 莰-7-yl)-exo-methyl formate (6b). The intermediate product (6b) is converted to cis-endo-7-(hydroxymethyl)norborn-2-exo-alcohol (F1) in the presence of sodium hydroxide (NaOH) and methanol (MeOH).

Specific examples of polycarbonate polymers in accordance with the present invention can be prepared by conventional techniques including, but not limited to, polymer method embodiments 1-12, and can be selected from homopolymers, such as containing derivatives. a chemical formula A to G and/or I to XV or a random copolymer, or a block copolymer, or an alternating copolymer, which is selectively considered herein as a random copolymer, a block copolymer, and an alternating copolymer , a single type of homopolymer of repeating units. Particular embodiments of the random, block and alternating polycarbonate copolymers according to the present invention may comprise two or more types derived from at least one chemical formula A to G and optionally at least one repeating unit of formulas I to XV.

Particular embodiments of some polycarbonate polymers as described above may comprise repeating units derived from polycyclic 2,3-diols selected from each of Formulas A to G or selected from any one or both of such chemical formulas. .

Specific examples of such polycarbonate polymers include those derived from two polycyclic 2,3-diol monomers, for example, represented by or selected from Chemical Formula A, Chemical Formula B, and Chemical Formula C, Repeating units, the percentage of moles of such repeating units may be from 1 to 99, from 10 to 90, from 30 to 70, or any other sub-ratio of any of the listed ratios, which provides the total unit of the repeating units 100 mole percentage.

Specific examples of some of the polycarbonate polymers of the present invention include, for example, a monomer represented by or selected from the chemical formula A, formula B, and formula C, and the specific embodiments can be understood to include The percentage of moles, where any single mole percentage is 1, any single mole percentage is 98, and any other minor proportions thereof. Without any limitation, this percentage of moles includes from 1 to 1 to 98, from 10 to 10 to 80, from 33.33 to 33.33 to 33.33, and the total number of such repeat units provided is 100 mole percent.

For specific embodiments of some of the polycarbonate polymers according to the present invention, each of R ⁵ and R ^{6 of} Formulas A through G can be independently selected from -(CH ₂ ) _p OH, wherein p is 0, 1, 2 or 3. For other such embodiments, for at least one of R ⁵ and R ⁶ , the p-system is independently 1, 2 or 3, for example, when p is 1, -CH ₂ OH is provided. In still another specific embodiment, for each of R ⁵ and R ⁶ , the p-system is independently 1, 2 or 3.

In the examples provided below, a general procedure is provided for polymer compositions of the formula according to the invention. Specific examples of such polymer compositions are here selectively considered to be TFU polymer compositions, including specific examples of polymers, carrier solvents, and fluxes such as formic acid (FA). It should be understood that each of the TFU polymer compositions mentioned has actually been manufactured and several evaluation reports have been generated, and the inventors believe that this provides a general procedure sufficient to operate the demonstration in accordance with the specific implementation of the present invention. The examples can be implemented as such, and are useful for providing microelectronic components during and after their components are placed on the substrate, as well as sufficient fluxing activity to provide superior soldering.

As used herein, "flux" is understood to mean a chemical cleaner that promotes soldering by removing the oxidation of the metal by bonding. Flux may include, but is not limited to, an acidic, neutral, or basic composition. Illustrative examples of fluxes include, but are not limited to, formaldehyde, formic acid, 2-nitrobenzoic acid, malonic acid, citric acid, malic acid, and succinic acid. Other exemplary fluxes include oxalic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, tartaric acid, lactic acid, mandelic acid, glyceric acid, valeric acid, Caproic acid, phenylacetic acid, benzoic acid, salicylic acid and amine benzoic acid. For ease of comparison and understanding, formic acid (FA) is used as a fluxing agent in the following examples, and the exemplary operation FA of such an embodiment provides excellent fluxing by the solder reflow data presented. In addition, storage stability data is provided to demonstrate storage of the polymer formulation specific embodiments of the present invention at elevated temperatures, in the presence of FA or other commonly used fluxes, and does not indicate any significant implementation. The M _w change of the polymer in the examples (see Tables 5 and 6 below).

As used herein, "carrier solvent" shall be taken to mean a solution for forming a selected embodiment of a polymer according to the present invention, and a selected flux to form a polymer composition of the present invention. Solvent. It will be further appreciated that the carrier solvent is such that it does not substantially react with the selected polymer embodiment and the selected flux. It can therefore be said that such polymer composition embodiments will exhibit the desired storage stability and also provide the desired adhesion, fluxing and underfill. Exemplary carrier solvents include, but are not limited to, cyclohexanone, cyclopentanone, diglyme, γ-butyrolactone (GBL), N,N-dimethylacetamide, N,N-dimethyl Carbenamide, anisole, methyl 3-methoxypropionate, tetrahydrofuran, and mixtures thereof.

Further, when the solder reflow data presented below is obtained using tin-copper eutectic solder balls (Sn99.3Cu0.7), other types of solders, especially lead-free solders, such as SAC305 (purchased from MG) Chemicals of Sn96.5Ag5Cu0.5) or K100 and K100LD (Sn99.4Cu0.6 and Sn99.5Cu0.5, respectively, available from Kester), need to be calibrated with or without any specific formulation. . Still further, it is to be understood that the inventors have exemplified the operation of the TFU polymer composition which does not have a single effective effect by the examples provided below, but rather the polymer specific embodiment, the carrier solvent and many formulations of the flux can be Made to work with a wide range of microelectronic component assemblies. That is, the polymer composition according to the present invention can be quickly adapted to the decomposition temperature, adhesion, _Mw, and fluxing activity to provide an excellent solution for a wide range of assembly processes.

In summary, a specific embodiment of the polymer composition of the present invention having a formic acid (FA) system used as a flux is prepared and evaluated to demonstrate the range of its fluxing activity. Referring to Table 3, Examples C1-C3 can be observed to demonstrate solder extension or reflow, such as a controlled solder sample having a diameter of about 1.6 times the extended solder sample, C4, the diameter of the original solder ball shown. When the FA is only a flux used in the foregoing reflow embodiment, it should be understood that other fluxes, such as the aforementioned fluxes, also fall within the specific embodiment of the TFU polymer composition of the present invention. range. Further, when solder fluxing embodiments C1-C3 are applied to the syringe application of the chemical formula of Examples B1-B3, any other suitable method for applying the formulation can be used. Thus, in addition to syringe applications, exemplary application methods include, among other things, spin coating, spray coating, dip coating, and knife coating.

In the examples and tables shown below, several trade names and/or abbreviations are used to distinguish the ingredients of the specific embodiments of the polymer compositions of the present invention. In most instances, such embodiments also provide the full name of the ingredient, and the chemical names of some of the ingredients may not be fully presented in the examples.

Example A. Synthetic polymer Polymerization of Example 1: cis-exo-2,3-norbornane dimethanol and cis-endo-2,3-norbornane dimethanol

22.5 g of cis-exo-2,3-norbornane dimethanol (144 mmol), 15 g of cis-endo-2,3-norbornane dimethanol (96 mmol), 51.3 g of diphenyl carbonate (240 mmol) And 12 mg of lithium hydride (1.5 mmol) were added to a multi-necked reaction vessel of suitable size and equipment. The contents of the vessel were heated to and maintained at 120 ° C, maintained under nitrogen for a period of time sufficient to form a reaction solution and then maintained at this temperature for two hours. Stable stirring was continued under nitrogen. The pressure in the reaction vessel was then isothermally lowered to 10 kPa and stirring was continued for another hour. The pressure of the vessel was further isothermally lowered to 0.5 kPa, and the stirring was again for another 1.5 hours, then the temperature of the reaction solution was increased to 180 ° C and the temperature was maintained and stirred for another 1.5 hours. The contents of the reaction vessel were cooled to room temperature, tetrahydrofuran (800 mL) was added and stirred, and the final solution was filtered. The filtrate was then added dropwise to 8 liters of a 9:1 methanol:water solution, which gave rise to the desired polymer. After separating the precipitate and washing the precipitate with an additional 4 liters of a 9:1 methanol:water solution, a polymer having a dry weight of 30.7 g of a certain weight was obtained. The polymer yield was 70%, its molecular weight ( _Mw ) was 41,000, and the polydispersity index (PDI) was 1.70.

Polymerization of Example 2: 1,3-cyclohexanediol and cis-exo-2,3-norbornane dimethanol

Using the procedure in Example 1, except 20.5 grams of 1,3-cyclohexanediol (176 mmols (TCI, Portland, OR)); 15.5 grams of cis-exo-2,3-norbornane II Methanol (99 mmols); 56.6 g of diphenyl carbonate (264 mmols), and 13.2 mg of lithium hydride (1.7 mmols) were charged to the reaction vessel. The yield of 28.1 grams of polymer was 69%. The polymer had a _Mw of 47,000 and a PDI of 1.75.

Polymerization of Example 3: 1,3-cyclohexanediol and cis-endo-2,3-norbornane dimethanol

Using the procedure in Example 1, except 19.2 grams of 1,3-cyclohexanediol (165 mmols, TCI USA); 14.5 grams of cis-endo-2,3-norbornane dimethanol (93 mmol); 53 grams Diphenyl carbonate (248 mmol) and 10.1 mg of lithium hydride (1.3 mmol) were charged into a reaction vessel. A polymer of 28.7 grams was obtained with a yield of 76%. The polymer had a _Mw of 38,000 and a PDI of 1.61.

The sum of the properties of the polycarbonates obtained from the polymerization examples 1-3 are summarized in Tables 1 and 2 below. In Table 2, the "terminal phenyl group" is based on the initial amount of the diphenyl carbonate feedstock and is not removed during the polymerization, indicating the chain-terminal phenyl percent molar value of the theoretical value of phenol;""Mole%" provides the value as determined by ¹ H NMR analysis as indicated in the polymer derived from cis-exo- or cis-endo-2,3-norbornane dimethanol monomer. Percentage of monomer units; and the column "soluble" is representative of the target resin content of the polymer (RC, 20 wt%) being soluble or insoluble in the quality of the specified solvent, where "A" is considered to be benzene Methyl ether and "G" are regarded as γ-butyrolactone.

Polymerization of Example 4: cis-exo-2,3-norbornane dimethanol terpolymer

Using the procedure of Example 1, except 25.0 g (160 mmol) of cis-exo-2,3-norbornane dimethanol and 34.3 g (185 mmol) of diphenyl carbonate and 6.4 mg (0.80 mmol) of lithium hydride were used. Into the reaction vessel. After initial polymer precipitation, the material was redissolved in tetrahydrofuran and precipitated again into pure methanol. After filtration through a power vacuum oven and drying, 23.5 g of a white polymer was obtained. The polymer properties are summarized as follows: M _w = 72,000, PDI = 3.0, T _g = 85 ° C, T _d50 = 313 ° C.

Polymerization of Example 5: 5-Exo-phenyl-cis-endo-2,3-norbornane dimethanol homopolymer

Using the procedure in Example 1 except 25.0 g (108 mmol) of 5-exo-phenyl-cis-endo-2,3-norbornane dimethanol and 23.1 g (108 mmol) of diphenyl carbonate and 58.0 mg ( 0.55 mmol) of sodium carbonate was charged into the reaction vessel. The polymer solution dissolved in tetrahydrofuran was added dropwise to the pure methanol during the precipitation. After filtration through a power vacuum oven and drying, 19.6 g of a white polymer was obtained. The polymer properties are summarized as follows: M _w = 63,000, PDI = 2.0, T _g = 114 ° C, T _d50 = 321 ° C.

Polymerization of Example 6: 5-Exo-phenyl-cis-exo-2,3-norbornane dimethanol homopolymer

Using the procedure of Example 1, except 10.0 g (43 mmol) of 5-exo-phenyl-cis-exo-2,3-norbornane dimethanol and 9.2 g (43 mmol) of diphenyl carbonate and 1.7 mg ( 0.22 mmol) of lithium hydride was charged into the reaction vessel. The polymer solution dissolved in a mixture of dichloromethane and tetrahydrofuran was added dropwise to the pure methanol during the precipitation. After filtration through a power vacuum oven and drying, 9.1 g of a white polymer was obtained. The polymer properties are summarized as follows: M _w = 49,000, PDI = 2.0, T _g = 115 ° C, T _d50 = 284 °C.

Polymerization of Example 7: trans-2,3-norbornane dimethanol homopolymer

Using the procedure of Example 1, except that 70.0 grams (448 mmol) of trans-2,3-norbornane dimethanol and 96.5 grams (450 mmol) of diphenyl carbonate and 238 mg (2.24 mmol) of sodium carbonate were charged. In the container. The polymer solution dissolved in tetrahydrofuran was added dropwise to the pure methanol during the precipitation. After filtration through a power vacuum oven and drying, 75.4 g of a white polymer was obtained. The polymer properties are summarized as follows: M _w = 177,000, PDI = 2.1, T _g = 81 ° C, T _d50 = 360 °C.

Polymerization of Example 8: isosorbide homopolymer

Using the procedure of Example 1, except 102.3 grams of isosorbide (0.7 mol, Cargill Corporation, Minneapolis, Minnesota); 149.95 grams of diphenyl carbonate (0.7 mol); and 3.0 mg of carbonic acid铯 (0.01 mmol) was charged into the reaction vessel. The crude polymer was dissolved in γ-butyrolactone (GBL). After precipitation in 7:3 isopropanol: water, filtration and hollow drying, about 119 g of poly(isosorbitol) isomer was obtained. The polymer properties are summarized as follows: M _w = 38,500, PDI = 2.61, T _g = 167 ° C, T _d50 = 376 ° C.

Polymerization of Example 9: isosorbide and trans-2,3-norbornane dimethanol

The following materials were added to a 250 mL round flask equipped with a magnetic stirrer of the appropriate size: 13.17 grams of isosorbide (90 mmol, Cargill), 14.09 grams of trans-2,3-norbornane dimethanol ( 90 mmol), 38.63 g of diphenyl carbonate (180 mmol), and 95.6 mg of sodium carbonate (9.0 mmol). The flask was vented to 1.3 kPa and refilled with nitrogen three times. When the flask was immersed in an oil bath at 120 ° C, the contents were maintained under a nitrogen atmosphere. The reaction was maintained at 120 ° C for two hours and under a nitrogen atmosphere. The contents of the flask were then depressurized to 10 kPa for one hour at 120 °C. Immediately thereafter, the oil bath temperature was gradually increased from 120 to 180 ° C at 10 kPa during which most of the phenol was distilled and collected in a liquid nitrogen cooling cylinder. The pressure was gradually reduced to 0.7 kPa and the reaction was maintained at 180 ° C for another two hours. The reactants in the flask were cooled to room temperature and dissolved in a suitable amount of tetrahydrofuran, such as 150 mL, with a rotary shock. The solution was further diluted to 500 mL with tetrahydrofuran and filtered. The filtered solution was added dropwise to 5 L of pure methanol. The white polymer (70 ° C, 29.4 Torr water vacuum) was collected by filtration in a vacuum oven for 18 hours and dried. The dry polymer weighed 30.2 grams. The properties of the polymer are summarized as follows: M _w = 32,000, PDI = 1.94, T _g = 116 ° C, T _d50 = 372 °C.

Polymerization of Example 10: isosorbide and 1,4-cyclohexanedimethanol

Using the procedure of Example 10, except that 29.04 grams of isosorbide (199 mmol, Cargill Corporation), 28.7 grams of 1,4-cyclohexanedimethanol (199 mmol), 85.2 grams of diphenyl carbonate (398 mmol): 211 mg of sodium carbonate (19.9 mmol) was charged into the reaction vessel. The dry polymer weighed 65.1 grams. The polymer properties are summarized as follows: M _w = 72,000, PDI = 2.84, T _g = 110 ° C, T _d50 = 373 ° C.

Polymerization of Example 11: cyclic norbornane spirocarbonate homopolymer

The second butyl lithium (0.21 mL in cyclohexanone, 1.4 M) was added to the snail [L-[2.2.1] heptane-2 dissolved in toluene (200 mL) at 0 ° C in a nitrogen blanket. , 5'-[1,3] two ]-2'-ketone (15 g, 82.3 mmol). The reaction mixture was stirred at 0 ° C for 5 hours and then gradually allowed to warm to room temperature. After the polymer was precipitated from methanol, it was continuously stirred at room temperature for another 12 hours, and dried under vacuum to obtain 9 g of a white polymer. The _Mw of the polymer was determined to be 32,000, while the PDI was 1.63 and _Td50 = 284 °C.

B. Flux Formulation Example Example B1: Formulation of polycarbonate from 1,3-cyclohexanediol and endo-endo-2,3-norbornane dimethanol with formic acid in GBL

The dry polymer (4.54 g) prepared by the following procedure in Polymer Example 3 was added with γ-butyrolactone (GBL) to give a polymer solution having a total weight of 12.8 g (35.3 wt% resin content). . Clarified, sticky The homogeneous, homogeneous polymer solution was mixed by roller for at least 12 hours. The viscous solution was filtered through a 1.0 μm disc filter made of PTFE, and the viscosity was 17500 cPs after testing at 25 ° C with a Brookfield viscometer (Model DV I Prime). Formic acid (0.67 g, 5 wt% of the total solution) was then added and a homogenous formulation was obtained after 8 hours of roll mixing.

Example B2: Formulation of polycarbonate from isosorbide and endo-exo-2,3-norbornane dimethanol and formic acid in GBL

A polycarbonate formulation according to a specific embodiment of the invention was prepared according to the procedure described in Example B1, which produced 15.0 grams of a matrix polymer solution (35.0% by weight of resin) with 5.25 grams of dry polymer from Polymer Example 9. Content)). The viscosity was tested to 4600 cPs. Formic acid was added to 0.78 grams.

Example B3: Formulation of polycarbonate from isosorbide and 1,4-cyclohexanedimethanol with formic acid in GBL

A polycarbonate formulation according to a specific embodiment of the present invention was prepared according to the procedure described in Example B1, which produced 10.0 grams of a matrix polymer solution (20.0% by weight of resin) with 2.00 grams of dry polymer from Polymer Example 10. Content)). The viscosity was 8000 cPs after testing. Formic acid was added to 0.52 g.

C. Solder flux formulation with formic acid in GBL

The formulations of Examples B1-B3 were used to provide data for the evaluation of C1-C3, respectively, as shown in Table 3. The procedure used in these examples was as follows: The formulation was injected onto a copper plate (1.7 cm x 3.4 cm) of a partially oxidized surface with a 27-dose injection as clearly spotted. Solder balls (Sn99.3 Cu0.7; 600 μm) were carefully transferred to each point on the copper plate. Entire version The device is placed on a device and then subjected to thermal reflow, such as through a reflow oven, by increasing the ambient temperature around the plate from room temperature to between 230 and 260 ° C within two minutes. The final temperature is then maintained for another two minutes before allowing the plate to return to room temperature. It can be observed that during the transfer of the plate carrying the placed solder balls, each point of the polymer composition maintains its placed solder balls in place, so after the solder material is reflowed, as determined, when compared to the control group (C4), compared to 930 to 990 μm, it showed excellent fluxing. The formulation of Control Group (C4) is Formulation B2 without formic acid. The solder reflow results of Examples C1-C4 are shown in Table 3 below.

D. Thermal stability example

D1: Isothermal thermogravimetric analysis of polycarbonate from isosorbide and endo-exo-2,3-norbornane dimethanol

The polymer composition was prepared from a polymer prepared by the method of Polymer Example 9 (M _w = 32,000) and an appropriate amount of γ-butyrolactone. The composition was spin-coated onto a four-ply substrate and baked at 120 ° C for 10 minutes to form a clear film. A sample of the film was peeled off from the substrate and analyzed by isothermal thermogravimetric analysis at 220 °C. After one hour, the weight loss was less than 2% compared to the initial membrane weight. The weight loss of similar samples at 260 ° C in less than one hour was less than 5%. It is conceivable that the material has thermal stability in the range of 200 ° C to 260 ° C.

D2: Film thickness evaluation during thermal reflow

The polymer composition was prepared from a polymer prepared by the method of Polymer Example 9 (M _w = 32,000) and an appropriate amount of γ-butyrolactone. The composition was spin-coated onto a four-ply substrate and baked at 120 ° C for 10 minutes to form a film having a suitable thickness of 2 μm. The tantalum substrate is heated in the reflow oven by increasing the ambient temperature around the plate within two minutes from room temperature to between 230 and 260 °C. The substrate was maintained at its temperature for another two minutes and then cooled to room temperature. The final film thickness was recorded and compared to the initial film thickness of the heated money. As shown in Table 4, the thickness variation system 1%, and typical film thickness measurement errors, and no deterioration in film quality was observed. All data indicate that the material is suitable for use as a durable material between 230 and 260 °C.

E. Storage stability example of formula with formic acid

For the following examples, a formulation with formic acid (FA) dissolved in γ-butyrolactone was prepared and stored at 65 ° C for one week, after which the final molecular weight M _w (final) was determined. The _Mw ratio of Table 5 was determined by evaluating the ratio of _Mw (final) / _Mw (initial), where _Mw (initial) was determined by measuring its molecular weight before heating to 65 °C. As shown, each sample indicates the stability of the current storage.

F. Storage stability examples of formulations with other acidic fluxes

For each of the known acidic fluxes listed in Table 6 below, the poly(propylene carbonate) (Novomer Company) dissolved in γ-butyrolactone was prepared using a flux of the specified loading. The initial Mw was measured and the samples were stored at 95 ° C for 48 hours, after which the final M _w and M _w ratios were determined by calculating the ratio of M _w (final) / M _w (initial). For these formulations, when the storage time is shorter than the storage stability examples of the formic acid formulations reported in Table 5, it is believed that these formulations are stored at higher temperatures, and the conditions for these storage stability examples will be at least with formic acid storage. The conditions of the stability examples are as stringent. Thus, as shown, for each of the formulations shown in Table 6, it indicates stability.

It should now be understood that the specific embodiment of the TFU polymer composition according to the present invention provides the ability to flux the type of solder reflow for the bonding of the microelectronic component to the substrate in this exemplary operation, and before and during the solder reflow process. The effect then acts as an underfill connection to maintain the ability of such components to be in their original position. Additionally, it should be understood that such a TFU composition can encompass a variety of polymer embodiments, wherein such polymer embodiments can be adapted by and by calibrating such polymers and/or compositions of such polymers. M _w has the desired T _d50 . Further, it should be understood that any one or more of the foregoing known fluxes incorporate any one or more of the foregoing polymer embodiments and any one or more of the foregoing carrier solvents to form a TFU polymer composition contemplated in accordance with the present invention. Further, it should be understood that when the formulation examples exemplify polymer weight percentages from 20 to 35 or more, the polymer weight percentages of certain TFU polymer composition embodiments range from 15 to 50 and Still other from 10 to 80; wherein such a plurality of wt% of the polymer is effective to select the desired viscosity of the TFU composition and its formation into the final underfill characteristics.

It should be further appreciated that the TFU polymer composition of the present invention is useful for forming a plurality of microelectronic device components, wherein the first substrate has a plurality of first contacts disposed on the first surface, such as a semiconductor die having electrical The contact pad is disposed on the first surface through the electrical contact pad, and is electrically or physically connected to the second substrate, and the second substrate has a plurality of second contact pads disposed on the second surface, the first contact pad and The second contact pads are at least substantially joined to each other. The electrical and physical properties are bonded to one or both of the TFU polymer composition by providing solder preforms, such as solder balls, to individual contacts of one or both of the first and second plurality of ground pads. The first and second surfaces are thus completed by sealing the solder preform with the TFU polymer composition. Further completing the physical and electrical connection, the first and second substrates are passed through the TFU polymer layer and are in contact with each other to form a pre-assembled structure, which is then heated to effectively allow the solder preform to form the first and second plurality The temperature of the contact electrical connection can also be effective for the TFU polymer sealing solder preform and the physical connection of the first substrate to the second substrate.

Claims (12)

A TFU polymer composition comprising: a polymer comprising a polycarbonate having a molecular weight ( _Mw ) of from 5,000 to 300,000; a carrier solvent; and a fluxing agent. The polymer composition of claim 1, wherein the fluxing agent is selected from the group consisting of formaldehyde, formic acid, 2-nitrobenzoic acid, malonic acid, citric acid, malic acid, and succinic acid. The polymer composition of claim 2, wherein the fluxing agent is formic acid. The polymer composition of claim 1, wherein the polycarbonate is selected from the group consisting of poly(alkylene carbonate) or a polymer formed from stereospecific norbornanediol and/or dimethanol monomer. . The polymer composition of claim 4, wherein the polymer formed from the stereospecific norbornanediol and/or the dimethanol monomer is exo-exo-2,3-polynorzane. Carbonate and endo-endo-2,3-polynorbornane dimethyl carbonate polymer, 1,3-polycyclohexyl carbonate and endo-exo-2,3-polynorbornane dimethyl carbonate One of an ester polymer, a poly(isosorbitol carbonate) and a trans-2,3-polynordecane dimethyl carbonate polymer. The polymer composition of claim 1, wherein the polymer comprises a repeating derivative of the norbornanediol monomer, the norbornane dimethanol monomer, and the diol monomer represented by the chemical formulas I to XV. unit. The polymer composition of claim 1, wherein the polymer It is 15 to 80% by weight of the polymer composition. The polymer composition of claim 7, wherein the formic acid comprises from 0.5 to 10.0% by weight of the composition based on the total weight of the polymer. The polymer composition of claim 1, wherein the carrier solvent is selected from the group consisting of cyclohexanone, cyclopentanone, diglyme, γ-butyrolactone (GBL), N,N-dimethyl Acetamide, N,N-dimethylformamide, anisole, methyl 3-methoxypropionate, tetrahydrofuran, and mixtures thereof. The polymer composition of claim 9, wherein the carrier solvent is GBL. A method of forming a microelectronic component assembly, comprising: providing a first substrate having a first contact region disposed on a first surface; providing a second substrate having a second contact region disposed on the second surface Providing a solder preform disposed in one or more first contact regions or one or more second contact regions; forming a TFU polymer layer covering and sealing the solder preform; contacting the first surface of the first substrate with the second a second surface of the substrate, wherein the TFU polymer layer is disposed between the two, the first contact region is coupled to the second contact region, and a pre-assembled structure is formed therein; and the pre-assembled structure is heated to Effective (1) to cause the solder preform to be physically and electrically bonded to the one or more first contact regions to the one or more second contact regions, and (2) to form a polymeric underfill material that is physically coupled to the first and second substrates temperature. The method of claim 11, wherein forming the TFU polymer layer covering and sealing the solder preform system comprises forming such a layer overlying an active surface of the microelectronic device having solder balls disposed on the contact pads.