JPH11168156A - Sealed flip-chip assembly, its manufacture and its reproducing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sealed flip-chip assembly which is easy to produce, can be reproduced easily and as well as will not breakdown, and is easily reproducible. SOLUTION: A binder which fills a gap in at least one semiconductor device attached by a plurality of solder connections from a support substrate while the gap is being formed in the support substrate, and which can be reworked thermally is constituted in as follows. At least one kind of filler which exists in an amount of 25 to 75 wt.% is contained on the basis of the amount of a cross-linking resin (A) which is prepared by the reaction of at least one kind of a dienophile, comprising one or more functional groups with at least one kind of a polymer containing 2,5-dialkyl-substituted furan and which can be reworked thermally and on the basis of a component (B). As a result, a flip-chip assembly which is sealed with the filler is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed flip chip assembly, a method for manufacturing the same, and a method for recycling the same. In one aspect, the present invention is directed to a thermoset binder suitable for sealing a gap between a flip chip and a substrate.

[0002]

2. Description of the Related Art Controlled collapse chip connection (C
4) Or flip-chip technology was introduced in the 1960's as a method of connecting a substrate to a protected semiconductor device, such as a ceramic carrier, by solder bumps (Microel).
ectronics Packaging Handbook, R. Tummala & EJ Rym
aszewski, VanNostrand Reinhold, NY1989). The high melting solder bumps on the device cause the solder on the substrate to flow along with the corresponding pads on the substrate to form a conductive bond between the device and the substrate. Subsequently, it was found that the presence of the binder (flip chip encapsulation), typically a filled thermoset binder, protects the device from moisture and the surrounding environment and enhances device fatigue life performance.

[0003] Flip chip technology requires high density in area and capacity, small footprint, high productivity, and the time and costly steps involved in current packaging technologies such as resin transfer molding for encapsulated chips. It is rapidly becoming popular for a number of reasons, such as omitting it. This technique uses chip carriers or substrates such as various ceramics (eg, alumina) and organics (eg, epoxy / fiberglass laminates). With the advent of multi-chip modules, narrow die-to-die spacing, and package configurations such as flip-chip placement on expensive multi-component boards, the repair or rebuild of defective flip-chips is of rapid interest. Typical flip chip processing is (Y. Tsukada,
Y. Mashimoto, N. Watanuki, Proceedings of the 43rd
Electronic Componentsand Technology Conference 199
3 IEEE, p199-204), forming solder bumps on carriers, applying solder paste, and SMT (Surface Mount Technology)
Install a flip chip with bumps together with other parts such as chips, resistors, etc. If the carrier is a multi-component board, re-irradiate infrared rays, inspect with X-rays, conduct an electrical test, After performing the sealing and post-curing, it involves performing a final inspection. If the flip chip is found to be defective in the electrical test, the chip is then heated and removed,
The bumps are fixed, the replacement tip is placed, and sent back to the above process. If the chip is found to be defective after the final inspection, shear with heat to break the crosslinked epoxy and remove the chip. This is followed by a cumbersome repositioning step due to the presence of cross-linking material, tip placement, IR re-irradiation and other subsequent steps in the process.

[0004] Conventional flip chip binders are thermoset systems and are irreversibly cross-linked after being applied under the chips. One example of a formulation is (DWWang, and KI Papatho
mas, IEEE Transaction on Components, Hybrids and Ma
nufacture Technology, 16 (8), December 1993, p 863-
867), liquid epoxy resins such as bisphenol A epoxy or cycloaliphatic epoxies, curing agents such as anhydrides with suitable accelerators, fillers such as silica and other additives.

[0005]

Regeneration of semiconductor devices is an expensive and time-consuming process. If the device needs to be replaced recently, the device must be removed in a destructive manner as described above. Accordingly, it is desirable to provide an easy and non-destructible reproducible method and flip chip assembly.

[0006]

According to the present invention, a support substrate; at least one of a plurality of solder connections extending from the support substrate and attached to the support substrate while forming a gap.
At least one dienophile comprising: a semiconductor device; and a thermally reworkable binder filling the gap, wherein the thermally reworkable binder has (a) a functionality greater than one. And a thermally reworkable crosslinked resin produced by the reaction of at least one 2,5-dialkyl-substituted furan-containing polymer; and (b)
25-75% by weight based on the amount of components (a) and (b)
A sealed flip-chip assembly is provided, which contains at least one filler present in an amount of 0.1 wt.

[0007]

DETAILED DESCRIPTION OF THE INVENTION There are several methods for producing thermally reworkable polymer chains of crosslinked resins. Thermally reworkable crosslinked resins can be made by a reaction in which at least one 2,5-dialkyl-substituted furan-containing polymer with more than one functionality is linked together by Diels-Alder addition. In one embodiment,
The 2,5-dialkyl substituted furan groups attach to the polymer chain or form part of the polymer. The reversible reaction of a dienophile with a furan to form a Diels-Alder adduct is represented as follows:

[0008]

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[0009] For thermally reworkable crosslinked resins,
All or a portion of the Diels-Alder adduct can be returned to the furan and dienophile by heating, such that the resin is liquid (flowable material).

In this embodiment, a cross-linking agent containing two or more dienophiles in its molecular structure can be used. These dienophiles are linked together by chemical bonds or bridging groups. Accordingly, the present invention also contemplates a flip chip binder composition (sealing material) comprising a polymer containing a portion of a 2,5-dialkyl-substituted furan and a crosslinking agent containing two or more dienophiles in the molecular structure. doing. Also, the dienophile binds to or forms part of the polymer chain. Two or more 2,5 in the molecular structure
Crosslinkers containing dialkyl-substituted furan groups can also be used.

In another embodiment, the dienophile is attached to a polymer chain to which a 2,5-dialkyl-substituted furan group is attached, or the chain is 2,5 as a part of the polymer chain. -Contains a dialkyl-substituted furan group.
Thus, the 2,5-dialkyl-substituted furan-containing polymer can also contain a 2,5-dialkyl-substituted furan moiety and a dienophile moiety.

The 2,5-dialkyl-substituted furan has its 3-
And may be substituted or unsubstituted at the 4-position. Preferred substituents are those having up to 10 carbon atoms such as, for example, alkyl or alkoxy groups, typically methyl, ethyl, 1-propyl, methoxy and 1-hexyloxy groups. Resins having unsubstituted furans at the 2 and 5 positions are prone to side reactions that irreversibly gel and hinder their reversibility.

[0013] The 2,5-dialkyl-substituted furan group may be bonded to the polymer chain of the polymer serving as the base of the crosslinked resin. The furan group can be directly bonded to the polymer chain via a chemical bond or a divalent organic bridge group, and therefore, as a part of a furan substituent or a compound bonded at the 3- or 4-position of furan. Can work. The alkyl substituents at the 2- and 5-positions of the furan can be the same or different and typically have up to 10 carbon atoms. Suitable alkyl groups are methyl, ethyl, 1-propyl and 1-hexyl groups. A suitable furan group that can be attached to the polymer chain is 2,5-dimethylfur-
3-yl, 2,5-diethylfur-3-methyl-fur-
4-yl, 2,5-ethylfurfuryl or 5- (1-butyl) furfuryl group.

The type of polymer chain to which the 2,5-dialkyl-substituted furan group can be bound is not limited. The polymer chains are polyethylene, polypropylene, polystyrene,
Chains of polyolefins such as poly (acrylic acid) or copolymers of ethylene and acrylic acid or esters, random or alternating copolymers of carbon monoxide and ethylenically unsaturated compounds (the description of this copolymer is further described below) Or a chain having a heteroatom, such as a polyamide or polyester chain. Preferably, the 2,5-dialkyl-substituted furan itself forms the backbone of the polymer backbone. In such a case, it is particularly preferred that each of the 2,5-dialkyl substituents of the furan is an alkyl group that forms part of the polymer and may or may not be substituted.

Such a structure has 1,4 in the polymer.
It can be produced by furanizing a copolymer of carbon monoxide containing a dicarbonyl compound and an ethylenically unsaturated compound, that is, converting a 1,4-dicarbonyl compound into a furan moiety. Further, by reacting carbon monoxide with an ethylenically unsaturated compound in the presence of a strong acid, a 2,5-dialkyl-substituted furan-containing polymer can be directly produced.

[0016] Completely alternating copolymers of carbon monoxide and ethylenically unsaturated compounds containing a 1,4-dicarbonyl compound in the polymer are known. The copolymer is, for example, EP-A-
121965, EP-A-181014 and EP-A-
It can be produced by palladium catalyzed polymerization using the known method of 516238. The polymer thus produced is an alternating copolymer of carbon monoxide and an ethylenically unsaturated compound, i.e., the polymer chains are arranged in an alternating sequence, and the monomer units are formed from carbon monoxide. Since it is a copolymer containing (carbonyl group) and a monomer unit derived from an ethylenically unsaturated compound, a carbonyl group is present at every four carbons of the polymer chain. Other copolymers of carbon monoxide containing 1,4-dicarbonyl and ethylenically unsaturated compounds are random copolymers, that is, copolymers in which polymer chains contain monomer units in random order. There can be. The latter copolymer is described, for example, in US-A-249.
It can be prepared by radical-initiated polymerization using methods known from US Pat.

The furanation of a copolymer of carbon monoxide and an ethylenically unsaturated compound can be carried out by methods known in the art, for example, A. Sen et al., "J. Polym. Science, Part A. Polym. Chem.
32 (1994), p. 841 ", by applying phosphorus pentoxide as a dehydrating agent or in US-A-3979.
As described in 373, this can be done by heating in the presence of a strong acid such as p-toluenesulfonic acid. These methods convert 1,4-dicarbonyl moieties in the polymer chain to furan moieties at various conversion levels by selecting reaction conditions.

It is preferable to use an alternating copolymer of carbon monoxide and an ethylenically unsaturated compound for furanization, but this is because the content of 1,4-dicarbonyl groups in the polymer main chain is high. This is because furanization in which furan groups are introduced at a high level is efficiently achieved. Nevertheless,
If a low degree of furanation is desired, the conversion of carbonyl groups to furan groups can be kept low.

The copolymer of carbon monoxide and the ethylenically unsaturated compound can be based on hydrocarbons as the ethylenically unsaturated compound. The copolymer can be based on ethylenic unsaturation, and α-olefins are suitable, especially α-olefins having up to 10 carbon atoms. Highly suitable are aliphatic α-olefins, especially those having 3 to 6 carbon atoms, more preferably those having straight-chain carbon atoms such as propene, 1-butene, 1-pentene and 1-hexene. . The copolymer can be regioregular or irregular, stereoregular or atactic.

The 2,5-dialkyl-substituted furan-containing polymer obtained by furanizing a polymer based on propene and carbon monoxide can be represented by the following formula:

[0021]

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The characteristic properties of the dienophile from which the Diels-Alder adduct is obtained are not limited, as long as the Diels-Alder adduct has the thermal stability such that the crosslinked resin can be reworked. Usually, the lowest temperature (above which temperature the reworkable crosslinked resin is reworked) depends on the highest temperature requirements of the semiconductor device used. Suitably the rework is performed at a temperature of about 100 ° C, preferably about 130 ° C to about 250 ° C, preferably about 200 ° C.

A suitable dienophile functional group is Y = Y (Y
Can be represented by C <, N- or -C≡C-). The dienophile is preferably an alkyne having an electron withdrawing group such as an ester or keto group on both sides of the ethyne moiety. For example, mono- and diesters of substituted but-2-ene-1,4-dione and butynedioic acid (ie, acetylenedicarboxylic acid). Other suitable dienophiles are compounds containing a but-2-1,4-dione moiety contained in a 5- or 6-membered ring, especially compounds having the general formula:

[0024]

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In the formula, X represents O, S, N, P or R;
R is alkylene, wherein at least one free valence is occupied by a bridging group connecting the dienophile to one or another dienophile chain of the polymer, and the remaining valences, if any, If so, it is occupied by a lower alkyl or acyl substituent or hydrogen, or preferably hydrogen. Suitably the lower alkyl substituent has up to 4 carbon atoms, for example a methyl or ethyl group. The dienophiles of the above general formula are cyclic derivatives of maleic anhydride, in particular maleimides (i.e. X represents O or especially N-). Examples of other suitable dienophiles include bis (triazolinedione), bis (phthalazinedione), quinone, bis (tricyanoethylene), bis (azodicarboxylate); diacrylate, maleate or fumarate polyester, There is acetylene dicarboxylate polyester.

As described above, in one specific use, a cross-linking agent containing two or more dienophiles in its molecular structure to obtain a Diels-Alder adduct is used. The dienophiles can be linked to one another by one or more bridging groups. For example, three dienophiles can be linked together by a trivalent bridge group. However, it is sufficient to use a crosslinker in which the two dienophiles are linked together by a divalent bridging group. The dienophiles may be linked to each other by chemical bonds.

The molecular weight and chemical nature of the bridge groups of the crosslinker can vary within wide limits. Such cross-linking agent modifications provide re-formable cross-linked resins that cover a wide range of mechanical properties. The bridge group can contain not only carbon atoms in the bridge, but also heteroatoms such as oxygen, silicon or nitrogen. The bridging group may be flexible or rigid.

For example, polymeric bridging groups having a flexible polymer chain, such as poly (alkylene oxide) or polysiloxane, and having a number average molecular weight of 300 or more provide a rubbery, reworkable crosslinked resin. When the polymer flexible chain has a number average molecular weight of 1500 to 5000 or more, a reworkable crosslinkable resin that can be replaced with a thermoplastic rubber can be obtained.

Thus, suitable crosslinkers of this type are poly (alkylene oxides), such as poly (ethylene oxide) or poly (propylene oxide), capped with bismaleimide, and bismaleimide-capped polysiloxanes, for example, Formula: H ₂ N—CH ₂ [—O—
_{SiR 2] n-O-CH} 2 -NH 2 (n is an average of 10 integer greater than, in particular the range of 20 to 70, R is independently, those with alkyl groups, in particular carbon atoms of up to 5,
Bismaleimide of a polysiloxane (preferably a methyl group). Bismaleimides of bisamino-capped poly (propene oxide), especially at least 300,
Particularly good results can be obtained by using those having a number average molecular weight in the range of 1500 to 5000.

It is also possible to use low molecular weight bridging groups, ie bridging groups typically having up to 20 carbon atoms in the bridge. Cycloaliphatic and aromatic bridge groups make the bridge groups rigid. The low molecular weight cycloaliphatic and aromatic bridging groups are hard and brittle, giving remoldable crosslinked resins having relatively high glass transition temperatures. Examples of low molecular weight alicyclic and aromatic bridge groups include a norbornane skeleton, a 1,3-phenylene group and the following formula: -f-
_{CH 2 -f -, - f-} O-f-O-f -, - f-O-f
-SO ₂ -f-O-f and -fC (CH ₃ ) ₂ -f-
(-F- represents a 1,4-phenylene group). Other suitable bridging groups are alkylene and oxycarbonyl (ester) groups, and combinations thereof. Suitable low molecular weight crosslinking agents include, for example, the following amines:
Bismaleimide, hydrazine, 2,4-diaminotoluene, hexamethylenediamine, dodecamethylenediamine, general formula:

[0031]

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Diamines and low molecular weight bisaminocapped (poly) siloxanes, for example of the general formula H ₂ N—CH ₂
[—O—SiR ₂ ] n—O—CH ₂ —NH ₂ (n is 1 on average)
-10, preferably 1-5, and R is preferably a methyl group). A mixture of isomers of the diamine of the above formula is commercially available from Hoechst. Very good results can be obtained with bis (4-maleimidophenyl) methane and dimethylbis [(N-maleimidomethyl) oxy] silane.

Other suitable crosslinkers based on maleic anhydride are compounds of the general formula:

[0034]

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Wherein A represents a bridge group as described above, in particular a bridge group having up to 20 carbon atoms in the bridge. In particular, the bridge group A is an alkylene group such as a hexamethylene group or -DO-CO-, or -CO-O-
A DO-CO- group (D represents a divalent hydrocarbyl group, for example, an alkylene group such as a hexamethylene group).

Furthermore, other suitable crosslinkers are butynedioic acids and diols such as ethylene glycol, poly (ethylene glycol), propylene glycol or polyesters based on poly (propylene glycol). These polyesters are low molecular weight crosslinking agents as described above, for example, 400 or more, 2000 to 6000.
Has a number average molecular weight in the range of

The present invention also relates to crosslinking agents such as bismaleimide-capped poly (alkylene oxide), especially bismaleimide-capped poly (propene oxide). At least 300 such crosslinking agents,
In particular, it has a number average molecular weight of 1500 to 5000. The bismaleimide of the polysiloxane has the general formula: H ₂ N—CH ₂
[—O—SiR ₂ ] n—O—CH ₂ —NH ₂ (n represents an integer of at least 1 and R independently represents an alkyl group, particularly one having up to 5 carbon atoms, preferably a methyl group ). Bismaleimide-capped polysiloxanes are N-hydroxymethylated maleimides with formaldehyde and then using generally known methods,
It can be produced by reacting with an appropriate dichlorodialkylsilane in the presence of a base and water.

As described above, one embodiment of the present invention relates to a crosslinking agent containing a 2,5-dialkylfuran moiety in its molecular structure. In this crosslinking agent,
The 2,5-dialkyl-substituted furan groups can be linked to each other via chemical bonds or bridge groups. The nature of the bridging group is generally the same as the bridging group of the crosslinker containing two or more dienophiles as described above. Examples of suitable crosslinking agents are bis (5-ethylfurfuryl) adipate, and the diamines and (5-
Ethylfurfuryl) bis-amide of acetic acid.

A 2,5-dialkyl-substituted furan moiety and / or
Alternatively, a portion of the dienophile can be linked to the polymer chain by a chemical bond or by a bridging group. This bridging group may be of the same type as the bridging group of the crosslinker. For example, the following can be mentioned. When the polymer is polystyrene, the maleimide as the dienophile can be linked to the polystyrene by tin (IV) chloride, which catalyzes the alkylation of polystyrene with N-chloromethylmaleimide, and the polymer is styrene / maleic anhydride. In the case of a copolymer, the 5-ethylfurfuryl group can be attached to polystyrene by esterifying the (styrene / maleic anhydride) copolymer with 5-ethylfurfuryl alcohol in pyridine. When the polymer is a copolymer of carbon monoxide containing a 1,4-dicarbonyl compound in the polymer chain and an olefinically unsaturated compound, 2,5-dialkylfuran and dienophile are, for example, US- A-3797374
Using a method known from
Can be bound by reacting with a secondary hydrocarbylamine. In this reaction, the 1,4-carbonyl form is converted to a pyrrole form which forms part of the polymer chain and is N-substituted by a substituted hydrocarbyl group. For example, a copolymer of carbon monoxide and an olefinically unsaturated compound containing a 1,4-dicarbonyl compound is reacted with maleic acid and a monoamide of hexamethylenediamine, or a copolymer of maleic acid and bis (4-aminophenyl) is used. Reaction with a methane monoamide can then be used to close the acid-amide moiety to the maleimide moiety. Thereby, N- (6
-Maleimidohexyl) pyrrole or N- ｛4-
A polymer having a [(4'-maleimidophenyl) methyl] phenyl dipyrrole moiety in the polymer chain results. 2,
If it is desired to use a polymer containing a 5-dialkyl substituted furan moiety and a dienophile moiety, the 1,4-dicarbonyl of the copolymer of carbon monoxide and the olefinically unsaturated compound is converted to a furan moiety and The other part of the 4,4-dicarbonyl form can be converted to an N-substituted pyrrole form whose N-substitution contains a dienophile.

The molecular weight of the reworkable crosslinked resin-based polymer can be varied within wide limits. The polymer has at least 500, preferably 700 to about 30,
Suitably it has a number average molecular weight in the range of 000, preferably up to about 20,000.

The amount of Diels-Alder adduct present in the thermally reworkable crosslinked resin depends on the amount of 2,5-dialkylfuran groups and dienophiles present in the composition from which the Diels-Alder adduct is formed. . One skilled in the art will recognize that for the crosslinker to be a solid material below the temperature at which the Diels-Alder adduct returns to the 2,5-dialkyl-substituted furan and dienophile, it is necessary to have some minimal amount of the Diels-Alder adduct present. Can understand.
The minimum amount depends on the type and molecular weight of the polymer on which the resin is based, and when a crosslinking agent is used, the number of dienophiles or 2,5-dialkylfuran groups per molecule of the crosslinking agent (functional number) Depends on. Low molecular weight polymers require large amounts of Diels-Alder adducts. If a crosslinker with higher functionality is used, the number of Diels-Alder adducts may be smaller.

In general, the ratio of furan groups to keto groups is about 1:
Good results can be achieved by using a 16- to about 4: 1 2,5-dialkylfuran-containing polymer. The molar ratio of the 2,5-dialkyl-substituted furan group to the dienophile is typically from about 10: 1 to about 1: 5, preferably from about 5: 1 to about 1: 3.

The flip-chip assembly sealed between the semiconductor device and the support substrate mounts the semiconductor device on the support substrate while forming a gap by a plurality of solder connections extending from the support substrate; Provided by filling a flip chip binder containing the following (a) and (b), which can be specifically reworked: (a) at least one dienophile having a functionality of more than 1 and at least one 2,2 Thermally reworkable crosslinked resin produced by the reaction of a 5-dialkyl-substituted furan-containing polymer, and (b) present in an amount of 25-75% by weight based on the amount of components (a) and (b) At least one filler.

The gap between the support substrate and the semiconductor device mixes the components of the thermally reworkable composition and precisely adds the composition to one or more sides of the device to fill the gap. Filling with the thermally reworkable composition can be accomplished using standard equipment such as a motionless mixer or syringe.

Solder bumps, typically about 95 parts lead and 5 parts tin alloy, provide a means of chip attachment to a substrate for subsequent use and testing. For further details on the C4 connection of the face down connection of the semiconductor chip to the substrate see US Pat. Nos. 3,401,126 and 342,904.
See 0. Typical solder bumps are formed on the protected semiconductor device contact side while the low melting solder on the corresponding substrate pad flows and creates a conductive path between the device and the substrate.

Normally, the semiconductor device is mounted on a substrate made of the material of the device, ie a material having a coefficient of expansion different from that of silicon.

The thermally reworkable composition typically comprises from about 25%, preferably from about 40% to about 75%, by weight of the binder, based on the weight of the composition (resin and filler). %, Preferably about 65% by weight of filler. The filler may be any of inorganic fillers suitable for semiconductor encapsulation, such as high purity fused silica, amorphous silica, or commercially available synthetic glass fillers. The filler can optionally be treated with a coupling agent such as a silane.

Typically, the filler and resin are chloride,
It should be at least substantially free of ionic impurities such as sodium and potassium (less than 20 ppm each). The method of the present invention provides a method in which the ionic impurities found in conventional methods using epoxy resin-based binders have been largely eliminated.

Furthermore, the thermally reworkable composition in the gap may be used and / or reworked at a temperature at which the thermally reworkable composition melts. Typically, the reworkable composition may be used or reworked at a temperature ranging from about 100 ° C, preferably from about 130 ° C to about 250 ° C, preferably about 200 ° C. If the resin is heated at an elevated temperature for a long period of time, for example at 200 ° C. for 12 hours, the resin undergoes irreversible crosslinking and is no longer thermally reversible.

The thermally reworkable flip chip encapsulating composition also includes an ion scavenger (eg, tricalcium phosphate), a free radical inhibitor (eg, hydroquinone,
Phenothiazole), flexibilizer (eg, silicone)
And other conventional additives used in flip chip encapsulation compositions.
If the rework time is long, it is preferred to use an ion scavenger and / or a free radical inhibitor.

Flip chips are bonded to various substrates, such as ceramic or organic chip carriers and multi-part printed circuit board substrates. Also, the carrier can be a multi-chip module where several chips are closely spaced on a single carrier. In many cases,
The cost of the substrate and equipment is high, and if one or more defective flip chips are found during testing, the manufacturer cannot afford to eliminate the entire substrate. The present invention allows a user to easily replace a defective chip without having to discard the entire package. Also, the present invention allows the user to omit the testing steps typically performed prior to encapsulation, since the thermally reworkable flip chip encapsulation composition of the present invention allows for easy regeneration and repair. To

The encapsulated flip chip assembly between the substrate and the semiconductor device made by the method of the present invention melts or softens the solder joints and converts the thermally reworkable composition to a liquid state. The reworking can be accomplished by heating the thermally reworkable composition filled in the solder joints and gaps at a temperature high enough to provide a liquid composition. Next, the semiconductor device and the liquid composition are removed from the supporting substrate to obtain a device-removed support. If you want to install new equipment on the board,
After straightening of the installation (removal and re-application of solder and / or solder flux on the board pads, if necessary), another device can be formed while the gap is being formed by reflowing the solder over the board pads. Forming the conductive connection, and then filling the gap thus formed with a new thermally reworkable composition containing (i) and (ii) below, thereby removing the device. Attached to the support. (I) a thermally reworkable crosslinked resin produced by reacting at least one dienophile having more than one functionality with at least one 2,5-dialkyl-substituted furan-containing polymer; (Ii) at least one filler present from about 25% to about 75% by weight, based on the amounts of components (i) and (ii). The new reworkable composition that fills the gap is cooled to a temperature low enough to solidify the resin, giving a regenerated assembly.

The thermally reworkable composition is post-cured,
Thermal and mechanical properties (eg, glass transition temperature and mechanical strength) can be increased. In order to prevent the thermal reversibility of the crosslinked resin, the thermally reworkable composition requires about 50
C., preferably at a temperature in the range of about 80.degree. C. to about 200.degree. C., preferably about 160.degree.
It can be heated after. If thermal reversibility is not required, the binder composition may be treated at a temperature in the range of about 150 ° C, preferably about 180 ° C to about 300 ° C, preferably about 250 ° C, for a period of up to about 4 hours, Curing can improve thermal properties.

Illustrative Embodiments The following illustrative embodiments describe the novel resins of the present invention, but are provided for illustrative purposes and do not limit the present invention. It doesn't make sense.

Example 1 In an autoclave, methanol and propene (approximately 1.
7: 1 by weight), heated to 90 ° C. and then supplied with carbon monoxide to a pressure of 72 bar. Palladium acetate, 1,3-bis (diethylphosphino) -propane, trifluoromethane (0.
6: 0.62: 1 and 0.3 pyridine by weight) and a methanol solution (15: 1 by volume) were injected and the reactor pressure during the reaction was increased to 72 by continuous feeding of carbon monoxide. Maintained at bar. The solvent was removed to obtain a propene / CO alternating copolymer having a number average molecular weight of 733.

Example 2 In an analogous manner to Example 1, an olefin / CO alternating copolymer having a number average molecular weight of 1472 (ethylene 27%; propylene 73%) was produced from propene and ethylene. The copolymer was dissolved in toluene and cyclized by heating under reflux in the presence of a catalytic amount of p-toluenesulfonic acid. The obtained polymer was analyzed by C-13 NMR. This analysis showed that 56% of the ketones in the starting polyketone had been cyclized to furan by the appearance of C-13 NMR signals (furan resonance) concentrated around 107, 114, 147 and 153 ppm. Was.

Example 3 A gel plate was set at 340 ° F. and the furanated polyketone prepared in Example 2 was applied to the plate. Theoretical amount of toluenediamine bismaleimide (Copimide Resin)
TDAB, Technochemie GmbH) was blended with the furanated polyketone until a homogeneous blend was obtained. The blend was removed from the gel plate and stored at room temperature.

Example 4 An ICI cone and plate viscometer was set at a temperature of 175 ° C. and stabilized at a set point. A small amount of the blend of Example 3 was placed on the plate and the temperature was increased. The cone was lowered and spun to get a good film between the cone and the plate. This was confirmed by lifting the cone to check for good film formation. The blend was then allowed to equilibrate for 90 seconds and the two viscosities were read while rotating the cone at a fixed speed.
The corn was lifted and the blend was removed from both the corn and the plate. The blend was cooled to room temperature to a crosslinked solid. The above sequence, i.e. loading the ICI cone and plate, measuring the viscosity at 175 C, removing the blend and cooling to room temperature, was repeated three times for the same blend. A continuous reading of the three viscosities is
3-5 poise, 3-5 poise and 3-5 poise. This experiment shows that the blend was in a cross-linked state at room
It shows that reversible alternating between low viscosity uncrosslinked liquid at 5 ° C. is possible.

Example 5 The furanated polyketone prepared in Example 2 was blended on a gel plate at 340 ° F. with a theoretical amount of TDAB. The blend was cooled to room temperature. The blend is further filled with silica filler (50% by weight of the total formulation) at 340 °.
F. The filled formulation was then removed from the plate and cooled to room temperature.

Example 6 An ICI cone and plate viscometer was set at a temperature of 175 ° C. and allowed to equilibrate to the set point. A small amount of the blend of Example 5 was placed on the plate and the temperature was increased. The cone was lowered and spun to get a good film between the cone and the plate. This was confirmed by lifting the cone for good film formation. Then
The blend was allowed to equilibrate for 90 seconds and the two viscosities were read while rotating the cone at a fixed speed. The corn was lifted and the blend was removed from both the corn and the plate. The blend was cooled to room temperature to a crosslinked solid. The above sequence, i.e. loading the ICI cone and plate, measuring the viscosity at 175 C, removing the blend and cooling to room temperature, was repeated three times for the same blend. Successive readings of the three viscosities were 20-25 poise, 20-25 poise and 25-30 poise. This experiment shows that the blend was in a cross-linked state at room
It shows that reversible alternating between low viscosity uncrosslinked liquid at 5 ° C. is possible.

Example 7 In an autoclave, methanol and propene (approximately 1.
7: 1 by weight), heated to 90 ° C. and then supplied with carbon monoxide to a pressure of 72 bar. Palladium acetate, 1,3-bis (di-o) in tetrahydrofuran
-Mitoxyphenylphosphino) -propane, a catalyst solution of trifluoromethanesulfonic acid (molar ratio of 1: 1.05: 2.1), and a methanol solution (15: 1 by volume) were injected twice and monoxide was added. The reactor pressure during the reaction was maintained at 72 bar by a continuous supply of carbon. The solvent was removed and the number average molecular weight was 1765 and the furan: ketone ratio was 0.1.
A 9: 1 propene / CO alternating copolymer was obtained.

Example 8 The furanated polyketone prepared in the previous example was blended on a gel plate at 340 ° F. with a theoretical amount of TDAB and 2.4% by weight phenothiazine. The blend was removed from the gel plate and cooled to room temperature. The blend was reheated on a gel plate and mixed with silica filler (50% by weight of the total formulation). The filled formulation was then removed from the gel plate and cooled to room temperature.

Example 9 An 8-layer (epoxy-glass fiber) printed circuit board masked with solder was placed on the print at 340 ° F. and heated for 2 minutes. The flip chip was placed on the board and the filled blend made in the previous example was filled into the chip from two sides of the chip for 2-3 minutes. The board was removed from the hot surface and cooled to room temperature. The chip was adhered to the board with the cross-linking composition between the device and the board. The board was returned to the gel plate. The chip was released from the board within 40 seconds as the formulation changed from a cross-linked solid to a liquid. The chip was then glued back in place with the adhesive already in place. The board was removed from the gel plate and cooled to room temperature. The board was returned to the hot surface and the above removal and reconnection procedure was repeated two more times.

Example 10 Similar to Example 1 except that 1,3-bis (di-o-methoxyphenylphosphino) was used in the catalyst solution instead of 1,3-bis (diethylphosphino) propane. By the method, an olefin / CO alternating copolymer (54.4% head-to-tail) having a number average molecular weight of 1616 was produced from propylene and ethylene. The copolymer was dissolved in toluene and cyclized by heating under reflux in the presence of a catalytic amount of p-toluenesulfonic acid. The obtained polymer was C-13
Analyzed by NMR. This analysis indicated that 57% of the ketone in the starting polyketone was cyclized to furan (furan: ketone ratio 0.66: 1).

Example 11 The furanated polyketone prepared in Example 10 and a stoichiometric amount of TDAB were added together with 6.5% by weight of phenothiazine in 180
C., mixed and poured into 1/8 inch thick metal molds. The moldings were quickly cooled and the properties of the resulting castings were tested. The flexural modulus of the sample was 628 ksi, similar to a crosslinked epoxy made with bisphenol A epoxy cured with an anhydride hardener. The dielectric constant and the dielectric loss tangent were 3.17 and 0.013, respectively.

Example 12 The furanated polyketone prepared in Example 7 was mixed with a 2: 1 stoichiometric ratio of methylene dianiline (Compimide Resin MDAB, Techn.
ology Gmbh), 0.15 phenothiazine per mole of MDAB and 0.015 per g furanated polyketone
g of 2-hexanoic acid. A DSC scan was performed at a heating rate of 20 ° C./min. Glass transition temperature is 1
Started at 05 ° C.

Example 13 The furanized polyketone prepared in Example 4 was converted to a theoretical amount of TD
One mole of AB and TDAB phenothiazines were reacted at 340 on a gel plate. Crush this sample,
It was placed in a pressure vessel with water at a ratio of 10: 1 (water: sample). The pressure vessel was kept at 60 ° C. for 20 hours, and the ions of the water extract were analyzed by ion chromatography. Extract contains 14 ppm acetate; less than 3 p glycolate, formate, propionate; less than 0.25 ppm chloride; 1.7 ppm sulfate; 4.8 ppm sodium; 0.8 ppm magnesium;
Calcium; 2.0 ppm ammonium ion.

Claims (29)

[Claims] A supporting substrate; a plurality of solder connections extending from the supporting substrate; a gap formed between the supporting substrate and the at least one semiconductor device; and a thermally filling the gap. A thermally processable binder comprising: (a) at least one dienophile having a functionality greater than 1 and at least one 2,5-dialkyl-substituted furan-containing polymer. And (b) at least one filler present in an amount of from 25 to 75% by weight, based on the amount of components (a) and (b). A sealed flip chip assembly. 2. The flip chip assembly according to claim 1, wherein said crosslinked resin is reworkable at a temperature in the range of 100 to 250 ° C. 3. The flip chip assembly according to claim 2, wherein the dienophile is an alkyne having electron withdrawing groups attached to both sides of an ethyne moiety. 4. The dienophile according to claim 1, wherein
The flip chip according to claim 3, which is selected from the group consisting of a compound containing a 2-ene-1,4-dione moiety and a compound containing a but-2-ene-1,4-dione moiety in a 6-membered ring. Assembly. 5. The flip chip assembly according to claim 2, wherein said dienophile is a cyclic derivative of maleic anhydride. 6. The thermally reworkable resin further comprises bismaleimide-capped poly (alkylene oxide), bismaleimide-capped polysiloxane, hydrazine bismaleimide, 2,4-diaminotoluene, hexa 3. The flip chip assembly according to claim 2, comprising a residue of a crosslinking agent selected from the group consisting of methylene diamine, dodecamethylene diamine, and substituted and unsubstituted diamines of the following formula. Embedded image 7. The flip-chip assembly according to claim 1, wherein the 2,5-dialkyl-substituted furan-containing polymer is produced by reacting carbon monoxide with at least one olefinically unsaturated compound. 8. The flip chip assembly according to claim 7, wherein said olefinically unsaturated compound is an aliphatic α-olefin. 9. The flip chip assembly according to claim 8, wherein said α-olefin is propene. 10. The polymer from which the crosslinked resin is made has a number average molecular weight of 500 to 30,000.
The flip chip assembly as described. 11. The flip chip assembly according to claim 4, wherein said 2,5-dialkyl-substituted furan-containing polymer has a ratio of furan groups to ketone groups of 1:16 to 4: 1. 12. The method according to claim 2, wherein the 2,5-dialkyl-substituted furan group and the dienophile in the 2,5-dialkyl-substituted furan-containing polymer are bonded in a ratio of 10: 1 to 1: 5. Flip chip assembly. 13. The flip chip assembly according to claim 2, wherein said dienophile is a crosslinking agent containing two or more dienophiles in its molecular structure. 14. The thermally reworkable crosslinked resin is prepared by reacting at least one dienophile having more than one functionality with two or more 2,5-dialkyl-substituted furan-containing polymers. 3. The flip chip assembly according to 2. 15. The thermally reworkable crosslinked resin comprises 2,5
3. The flip chip assembly according to claim 2, comprising a dialkyl-substituted furan moiety and a dienophile moiety. 16. The flip chip assembly according to claim 1, further comprising (c) a free radical initiator and / or an ion scavenger. 17. At least one semiconductor device is attached to the support substrate while forming a gap by a plurality of solder connections extending from the support substrate; and (a) and (b) capable of being thermally reworked into the gap. A) encapsulating flip-chip assembly method comprising the step of filling a flip-chip binder containing: (a) at least one dienophile having a functionality of more than 1 and at least one 2,5-dialkyl substitution A thermally reworkable crosslinked resin produced by the reaction of a furan-containing polymer; and (b) 25-75 based on the amounts of components (a) and (b).
At least one filler present in an amount of% by weight; 18. Heating the sealed flip-chip assembly at a temperature high enough to melt or soften the solder joints and convert the thermally reworkable composition to a liquid; 18. The method of claim 17 including the step of removing from the support substrate to provide a device removal substrate. 19. The apparatus for cleaning a removed support substrate to remove solder and thermally reworkable flip chip binder, thereby providing a cleaned support substrate; a plurality extending from the support substrate A second semiconductor device is attached to the cleaned support substrate while forming a gap between the support substrate and the support substrate by a solder connection; a new thermally reworkable (i) and (ii) ) Containing a flip-chip binder comprising: (i) a thermally reproducible polymer prepared by the reaction of at least one dienophile having a functionality greater than 1 with at least one 2,5-dialkyl-substituted furan-containing polymer; A processable crosslinked resin, and (ii) 25-75 based on the amounts of components (i) and (ii).
At least one filler present in an amount of weight percent; cooling the new thermally reworkable composition filled in the interstices to a temperature low enough for the resin to solidify, thereby providing a remanufactured assembly. Claim 18 comprising:
The described method. 20. The method of claim 18, wherein said crosslinked resin is heated to a temperature in the range of 100-250 ° C. 21. The flip chip according to claim 19, wherein the 2,5-dialkyl-substituted furan-containing polymer is produced by furanizing a copolymer of carbon monoxide and at least one olefinically unsaturated compound. Assembly. 22. The method according to claim 17, comprising heating the assembly to a temperature in the range of 70 to 200 ° C. for a time of up to 4 hours. 23. The method according to claim 17, comprising heating the assembly to a temperature in the range of 150 to 300 ° C. for a time of up to 4 hours. 24. The method of claim 17, wherein said 2,5-dialkyl-substituted furan-containing polymer is prepared by reacting carbon monoxide with at least one olefinically unsaturated compound. 25. The method according to claim 21, wherein said olefinically unsaturated compound is an aliphatic α-olefin. 26. The method according to claim 25, wherein said α-olefin is propene. 27. At least one of a plurality of solders extending from the support substrate and attached to the support substrate while forming a gap by a plurality of solder connections forming a gap between the support substrate and the semiconductor device.
Heating a sealed flip chip assembly containing two semiconductors and a thermally reworkable flip chip binder filling the gap, wherein the thermally reworkable flip chip binder comprises: A thermally reworkable crosslinked resin produced by the reaction of at least one dienophile having a high functionality with at least one 2,5-dialkyl-substituted furan-containing polymer; and (b) components (a) and ( containing at least one filler present in an amount of 25-75% by weight, based on the amount of b); the encapsulated process including removing the semiconductor device from a supporting substrate to provide a device-removed substrate. Reproduction method of flip chip assembly. 28. The apparatus further comprising cleaning the removed support substrate to remove solder and thermally reworkable flip chip binder, thereby providing the cleaned support substrate; extending from the support substrate. A second semiconductor device is attached to the cleaned support substrate while forming a gap between the support substrate and the plurality of solder connections; a new thermally reworkable (i) and Filling a flip-chip binder containing (ii): (i) Thermally prepared by reacting at least one dienophile having a functionality greater than 1 with at least one 2,5-dialkyl-substituted furan-containing polymer A cross-linkable resin which can be reworked into a mixture, and (ii) at least one filler present in an amount of from 25 to 75% by weight, based on the amount of components (i) and (ii); There thermally reworkable composition is cooled to a temperature low enough to the resin is solidified, whereby the method of claim 27 wherein including the step of providing a regeneration assembly. 29. The method of claim 28, wherein said 2,5-dialkyl-substituted furan-containing polymer is prepared by furanizing a copolymer of carbon monoxide and at least one olefinically unsaturated compound.