Recoverable and reworkable polymers for electronic packaging

Abstract

A composition, method, and device are disclosed. The composition includes a polymer formed by reacting an epoxy compound with an amine curing agent. The epoxy compound includes a Diels-Alder dimer and an ester moiety. The method includes providing a polymer formed by reacting the epoxy compound with the amine curing agent. The device includes a material including the polymer.

Description

[Technical field]

[0001] The present disclosure relates to electronic packaging materials, and more particularly, to epoxy-based electronic packaging materials. [Background technology]

[0002] Various polymeric materials (e.g., adhesives, thermal interface materials, underfills) are used in the manufacture of semiconductor and microelectronic devices. For example, underfills can be used in electronic packaging at the connections between semiconductor chips and circuit boards. When a semiconductor chip is connected to a circuit board, electrical connections are made between electrical terminations on the chip and corresponding electrical terminations on the circuit board. For example, these connections can be made using metal or polymeric materials that are applied as bumps (e.g., solder bumps) to the chip or circuit board terminals. The solder bumps are then aligned and brought into contact. The resulting assembly can then be heated to reflow the metal or polymeric material and solidify the connections. Gaps between the printed wiring board and the connecting components can be filled with underfills that can strengthen the interconnects and absorb stress from mechanical shock. Summary of the Invention

[0003] Various embodiments relate to a composition comprising a polymer formed by reacting an epoxy compound with an amine hardener. The epoxy compound comprises a Diels-Alder dimer and an ester moiety. In some embodiments, the composition comprises filler particles, which may be 40 to 60 wt.% of the composition. The amine hardener may be 4,7,10-trioxatridecane-1,13-diamine or 4,4-methylenebis(2-ethylaniline). The polymer may be depolymerized by treatment with a solution of an amine and a protic solvent. The epoxy compound may be Thiele acid glycidyl ether. The dimer may be cyclopentadiene. The dimer may undergo reverse dimerization at temperatures of approximately 30° C. or greater. The composition may also include a radical inhibitor.

[0004] Further embodiments relate to methods, including providing a polymer formed by reacting an epoxy compound with an amine curing agent. The method may also further include forming a composite material having the polymer and 40 to 60 wt.% of filler particles. In some embodiments, the composite material is a capillary underfill or thermal interface material. The method may also further include providing an electronic package including the polymer.

[0005] Further embodiments relate to a device. The device comprises a material comprising the polymer. In some embodiments, the material also comprises 40 to 60 wt.% filler particles. The material may be a capillary underfill or a thermal interface material. The device may be a multi-chip module.

[0006] The drawings contained in this application are incorporated in and form a part of this specification. They illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. The drawings are only illustrative of certain embodiments and are not intended to limit the invention. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a chemical reaction diagram illustrating a process for forming an epoxy-based polymer according to some embodiments of the present invention. [Diagram 2] 1 is a proton nuclear magnetic resonance ( 1 H NMR) spectrum and corresponding chemical structure of Thiele acid glycidyl ether (TAGE). [Figure 3A] FIG. 2 is a chemical reaction diagram illustrating the reaction between TAGE and n-butylamine, according to some embodiments of the present invention. [Figure 3B] FIG. 3B is a set of 1H NMR spectra collected at five time intervals while monitoring the example experiment of the TAGE / n-butylamine reaction shown in FIG. 3A. [Figure 3C]3C is a chart showing integrated signal intensities of peaks from the NMR spectrum shown in FIG. 3B. [Figure 4] FIG. 1 is a chemical reaction diagram illustrating a process of heating a TAGE-amine polymer according to some embodiments of the present invention. [Diagram 5] FIG. 1 is a schematic illustrating a process for reconditioning a capillary underfill containing a TAGE-amine polymer according to some embodiments of the present invention. [Figure 6] FIG. 6 is a schematic illustrating a process 600 for repairing a multi-chip module by reworking an epoxy-based material containing TAGE-amine, according to some embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] While the invention is susceptible to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It is to be understood, however, that it is not intended to limit the invention to the particular embodiments described. Instead, it is intended to cover all modifications, equivalents and alternatives falling within the scope of the invention.

[0009] FIELD OF THE DISCLOSURE Embodiments of the present invention relate generally to electronic packaging materials, and more particularly to epoxy-based underfill materials. Although the present invention is not necessarily limited to such applications, various aspects of the present invention may be understood by discussing examples using this context.

[0010] Various embodiments of the present invention are described herein with reference to the associated drawings, where like numerals refer to the same components. Alternative embodiments may be devised without departing from the scope of the present invention. It is noted that in the following description and drawings, various connections and positional relationships between elements are described (e.g., above, below, adjacent, etc.). These connections and / or positional relationships may be direct or indirect unless otherwise specified, and the present invention is not intended to be limited in this respect. Thus, the coupling of entities may refer to either direct or indirect coupling, and the positional relationship between entities may be direct or indirect. As an example of an indirect positional relationship, a reference herein to forming a layer "A" on a layer "B" includes the situation where there are one or more intermediate layers (e.g., layer "C") between layers "A" and "B", as long as the relevant characteristics and functionality of layers "A" and "B" are not substantially altered by the intermediate layers.

[0011] The following definitions and abbreviations are to be used in interpreting the claims and the specification. As used herein, the terms "comprises," "comprises," "includes," "includes," "has," "having," "containing," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, mixture, process, method, article, or device that includes recited elements is not necessarily limited to only those elements, and may include other elements not expressly recited or inherent to such composition, mixture, process, method, article, or device.

[0012] Hereinafter, for purposes of explanation, the terms "upper", "lower", "right", "left", "vertical", "parallel", "top", "bottom" and their derivatives refer to the described structures and methods as oriented in the drawings. The terms "overlying", "top", "overlying", "on top of", "located on" or "located on top of" mean that a first element, such as a first structure, is on a second element, such as a second structure, and there may be an intervening element, such as an interface structure, between the first and second elements. The term "direct contact" means that a first element, such as a first structure, and a second element, such as a second structure, are connected without any intermediate conductive, insulating or semiconducting layer at the interface of the two elements. It should be noted that the term "selective to", such as "a first element selective to a second element", means that the first element may be etched and the second element may act as an etch stop.

[0013] As used herein, the articles "a" and "an" preceding an element or component are not intended to be restrictive with respect to the number of instances (i.e., occurrences) of the element or component. Thus, "a" or "an" should be interpreted to include one or at least one, and the singular form of an element or component also includes the plural unless the number is clearly intended to be singular.

[0014] As used herein, the term "invention" or "the present invention" is an open-ended term and is not intended to refer to any single embodiment of a particular invention, but rather encompasses all possible embodiments described in the specification and claims.

[0015] Unless otherwise specified, ranges (e.g., time, concentration, temperature, etc.) set forth herein include both the endpoints and all numbers between the endpoints. Unless otherwise specified, the use of the tilde (~) or terms such as "about," "substantially," "approximately," "slightly less than," and variations thereof are intended to include the degree of error associated with the measurement of a particular quantity based on the equipment available at the time of filing this application. For example, "about" can include a range of ±8% or 5% or 2% of a given value, range of values, or one or more endpoints of a range of values. Unless otherwise specified, the use of such terms in conjunction with ranges applies to both ends of the range (e.g., "approximately 1 g to 5 g" should be interpreted as "approximately 1 g to approximately 5 g") and, in conjunction with the recited ranges, applies to each range within the recitation (e.g., "approximately 1 g to 5 g, 5 g to 10 g, etc." should be interpreted as "approximately 1 g to approximately 5 g, about 5 g to approximately 10 g, etc.").

[0016] For the sake of brevity, conventional techniques related to semiconductor device and integrated circuit (IC) manufacturing may or may not be described in detail herein. Additionally, various operations and process steps described herein may be incorporated into more comprehensive procedures or processes that include additional steps or functions not described in detail herein. In particular, the various steps in the manufacture of semiconductor devices and semiconductor-based ICs are well known, and thus, for the sake of brevity, many conventional steps are only briefly mentioned herein without providing well-known process details or are omitted entirely.

[0017] It should also be understood that compounds of materials are described in terms of the elements listed, for example, SiN or SiGe. These compounds include different percentages of the elements in the compound, for example, SiGe includes SixGe(1-x), where x is 1 or less, etc. Additionally, other elements may be included in the compound and still function according to the principles of the present invention. Compounds with additional elements are sometimes referred to herein as alloys.

[0018] Turning now to an overview of the technology more specifically related to the embodiments of the present invention, generally, electronic packaging components of semiconductor and microelectronic devices may include various polymeric materials, such as underfills, thermal interface materials (TIMs), adhesives, pastes, laminates, etc. For example, the gap between a printed wiring board and a connecting component (e.g., a semiconductor chip) may be filled with an underfill to strengthen the connection and absorb stress from mechanical shock. Epoxy-based polymeric materials are commonly used for these packaging materials. Epoxy-based materials, called two-part epoxies, include an epoxy compound / monomer (part A) mixed with a hardener or curing agent (part B), such as a primary amine. However, cracks may form in the underfill and other components, for example due to the action of high temperatures on materials with different coefficients of thermal expansion (CTE). These cracks may propagate into surrounding components, resulting in unreliability or failure of the device. For example, cracks in commonly used epoxy-based capillary underfills may reduce sidewall adhesion and propagate into the interlayer dielectric (ILD), solder, solder mask, etc. of the device.

[0019] Embodiments of the present invention may improve package yield and lifespan and may also enable scaling of MCMs. In some embodiments, an epoxy-based material (e.g., capillary underfill) is provided that includes a polymer that can be formed by reacting an epoxy compound (part A) having an ester moiety and a Diels-Alder dimer moiety (e.g., dicyclopentadiene moiety) with an amine curing agent (part B). For example, the epoxy compound may be Thiele acid diglycidyl ether (TAGE). The epoxy-based material may include a mixture of polymers and additional materials, such as fillers (e.g., silica particles), radical inhibitors, and the like. In some embodiments, the properties of the epoxy-based material may be tailored by the selection of the amine curing agent and / or filler (e.g., particle size and composition, weight percent (wt.%) of the filler in the composite).

[0020] The disclosed epoxy-based materials may be rehealable and reworkable. Healing of cracks, voids, and other defects in components such as TIMs, underfills, adhesives, etc., that contain epoxy-based materials may be accomplished by applying heat to the thermoreversible Diels-Alder dimer portion of the polymer. In some embodiments, depolymerization and removal of the material from the substrate may be accomplished by treatment with a solution containing an amine and a protic solvent. This mixture may react with the ester portion of the polymer, thereby depolymerizing the polymer so that the epoxy-based material can be washed away. This may allow for removal of defective chips without grinding or other methods that may damage the underlying laminate or other device components or both.

[0021] Referring now to the drawings, in which like numerals represent the same or similar elements, Figure 1 is a chemical reaction diagram illustrating a process 100 for forming an epoxy-based polymer, according to some embodiments of the present invention. In the process 100, an amine curing agent 110 is added to an epoxy compound 115 having an ester moiety and a thermally reversible Diels-Alder dimer moiety. In Figure 1 and other examples shown herein, this epoxy compound 115 is Thiele acid diglycidyl ether (TAGE).

[0022] TAGE can be formed by reacting Thiele acid (Formula 1) with glycidol (2,3-epoxy-1-propanol). Thiele acid (TA) is the Diels-Alder dimer of cyclopentadiene carboxylate. [ka]

[0023] However, other suitable epoxies may be used. For example, in some embodiments, the epoxy compound 115 may be a Diels-Alder dimer of 1,3-adamantanedicarboxylic acid.

[0024] The addition of curing agent 110 results in polymer 120 (also referred to herein as "TAGE-amine") that can be used in electronic packaging materials. Polymer 120 has ester moieties that can undergo catalytic depolymerization when mixed with protic solvents and amines. Polymer 120 also has thermally reversible dicyclopentadiene moieties that can allow for regeneration when a thermal stimulus is applied.

[0025] FIG. 2 shows the proton nuclear magnetic resonance (1H NMR) spectrum 200 and the corresponding chemical structure diagram 210 of TAGE. The TAGE sample from which the NMR spectrum 200 was collected was formed by mixing Thiele acid (TA) with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and dimethylaminopyridine (DMAP) in dichloromethane (DCM) at room temperature. In other embodiments, EDC may be replaced by another coupling agent, such as dicyclohexylcarbodiimide (DCC). The reaction mixture was stirred for about 2 hours. Glycidol was then added to obtain a crude mixture containing TAGE and about 5 to 10 mol % of impurities (e.g., mono-substituted glycidyl esters) as determined by proton NMR. The NMR spectrum of the crude product is not shown herein.

[0026] The monosubstituted impurity was removed by column chromatography using approximately 20 vol.% ethyl acetate in DCM. The NMR spectrum 200 shown was collected from a solution of the purified TAGE product in deuterated chloroform (CDCl3). The spectral peaks from the solvents (ethyl acetate, DCM and chloroform (CHCl3)) and the TAGE hydrogen atoms (a through j) are labeled at the appropriate positions in the NMR spectrum 200. The corresponding TAGE hydrogen atom positions (a through j) are labeled in the TAGE structural diagram 210.

[0027] Referring again to FIG. 1, the amine curing agent 110 includes two primary amine moieties (-NH2) attached to carbon atoms from the organic moieties that form the remainder of the molecular structure of the amine curing agent 110. These organic moieties are collectively represented as R in FIG. 1 and will depend on the type of curing agent used, as will be understood by those skilled in the art. The amine curing agent 110 may be any suitable curing / hardening agent for epoxy resins. In some embodiments, the amine curing agent 110 may be a curing agent commonly used in commercially available resins, such as, for example, Stycast® 1266 (manufactured by Henkel AG & Co., KGaA) (herein "Stycast 1266") or SUMIRESIN EXCEL® CRP-4160G (Sumitomo Bakelite Co., Ltd.) (herein "CRP-4160G"). The amine curing agents (part B) in Stycast® 1266 and CRP-4160G are referred to herein as StyB and 4160G. The structures of StyB (4,7,10-trioxatridecane-1,13-diamine) and 4160G (4,4-methylenebis(2-ethylaniline)) are shown in Formulas 2 and 3, respectively: [ka]

[0028] In some embodiments, the reaction to form the TAGE-amine (polymer 120) is substantially free of side reactions between amine moieties (e.g., derived from the amine curing agent 110) and cyclopentadiene moieties (derived from the TAGE). Side reactions between amine moieties and cyclopentadiene moieties may prevent proper formation of the TAGE-amine. For example, by-products and crosslinks formed by these side reactions may reduce or eliminate the recoverability and / or reprocessability of the TAGE-amine.

[0029] 3A is a chemical reaction diagram illustrating a reaction 300 between TAGE and an amine curing agent (n-butylamine) according to some embodiments of the present invention. In reaction 300, TAGE reacts with n-butylamine at room temperature (RT) to form a polymer ("TAGE-butylamine").

[0030] Figures 3B and 3C show the results of proton NMR (1H NMR) monitoring of an example reaction 300 between TAGE and n-butylamine. The monitored reaction 300 was carried out for about 168 hours in CDCl3. Hydrogen atom positions that can be used to follow the progress of the reaction by NMR are labeled "a," "b," and "c" in the depicted structures of TAGE and TAGE-butylamine. The NMR peaks (frequency (F1) or chemical shifts) corresponding to these positions are labeled accordingly in Figure 3B.

[0031] Figure 3B is a set of 1H NMR spectra 310 collected at five time intervals (t=0, 1 h, 18 h, 48 h, and 168 h) while monitoring the example experiment of the TAGE / n-butylamine reaction 300 shown in Figure 3A. The spectra show labeled peaks corresponding to the hydrogen atoms of the cyclopentadiene double bond (labeled "a" and "b"), the internal standard (dichloromethane, labeled "DCM"), and the hydroxyl hydrogen (labeled "c"), which is indicative of the formation of TAGE-butylamine.

[0032] 3C is a chart 320 showing the integrated signal intensities of peaks a, b, and c from NMR spectra 310 collected from reaction 300 at five time intervals. The signal intensities of peaks a and b (representing the cyclopentadiene double bond) remain substantially the same throughout reaction 300, while the signal intensity of peak c (hydroxyl group) increases as the TAGE-butylamine polymer is formed. This indicates that the TAGE-amine (polymer 120) can be formed without substantial side reactions / by-products.

[0033] In some embodiments, the TAGE-amine is produced using conventional reaction conditions for epoxy resin formation. To form a composite, an amount of filler may be added to the TAGE-amine. For example, silica (SiO2) particles having an average or maximum circumference of about 1 μm or both may be added to form a composite containing TAGE-amine and up to about 90 wt.% of filler. In some embodiments, the amount of filler is about 40 to 50 wt.% or 50 to 60 wt.%. Other examples of fillers that may be used in some embodiments may include polyhedral oligomeric silsesquioxane (POSS) particles, SiO2 particles of other sizes (e.g., about 10 μm), etc.

[0034] The adhesion capability (peel strength) of TAGE-amine films formed by reacting TAGE with Stycast B and curing at about 60°C was tested according to the American Society for Testing and Materials (ASTM) D4541-17 standard, where "TAGE-StyB" indicates that the TAGE-amine was formed using Stycast B (4,7,10-trioxatridecane-1,13-diamine) as the amine curing agent 110. Tests with TAGE-StyB (15 wt.% amine) coated on SiO2 plates yielded peel strengths of 0.5216 megapascals (MPa) and 0.8012 MPa, respectively. Tests with TAGE-amine (25 wt.% amine) coated on SiO2 plates yielded peel strengths of 22.62 MPa and 15.62 MPa, respectively. Tests without TAGE, using Stycast 1266 (parts A and B) as a control, yielded peel strengths of approximately 1 to 2 MPa.

[0035] Table 1 summarizes the experimental details of dynamic mechanical analysis (DMA) of epoxy-amine composites. The storage (elastic) modulus E' was experimentally determined for the filler and epoxy-amine composites. The epoxy-amines include TAGE-StyB, TAGE-4160G, BPADE-StyB (BPADE is a diglycidyl ether of bisphenol A), and TAGE:BPADE-StyB (TAGE:BPADE is a 1:1 mixture of TAGE and BPADE). Composites with different filler contents and curing conditions were tested, as shown in Table 1. Additionally, Table 1 shows the coefficient of thermal expansion (CTE) and glass transition temperature (Tg) determined for the TAGE-StyB composites.

[0036] 4 is a chemical reaction diagram illustrating a process 400 for heating / rejuvenating TAGE-amine, according to some embodiments of the present invention. The TAGE-amine shown may be formed according to process 100 (FIG. 1). Increasing the temperature of the TAGE-amine (e.g., to about 120° C.) may cause de-dimerization of the cyclopentadiene moieties, thereby "softening" the polymer. Reducing the temperature may cause the cyclopentadiene moieties to dimerize again, thereby "rejuvenating" the polymer.

[0037] [Table 1]

[0038] In some embodiments, the rehealable TAGE-amine material may include a radical inhibitor (e.g., butylated hydroxytoluene (BHT), phenothiazine, etc.). This may prevent side reactions during process 400 that would prevent rehealing. In some embodiments, electronic packaging epoxy-based materials including TAGE-amine may be rehealed by application of a thermal stimulus as in process 400. For example, TIMs, underfills, adhesives, etc. may be prepared with TAGE-amine polymers, and in some embodiments, radical inhibitors. In some embodiments, the amount and composition of fillers added to the material may be adjusted to optimize the rehealing properties.

[0039] 5 is a schematic diagram illustrating a process 500 for reconditioning a capillary underfill 505 containing TAGE-amine, according to some embodiments of the present invention. FIG. 5 shows a portion of an electronic packaging module (collectively, "module 510") before (510A) and after (510B) reconditioning. Module 510 includes chip 520, laminate 525, solder mask 530, and connectors 535 to solder balls 540. For purposes of illustration, additional components of module 510 are not shown. However, these components are known to those skilled in the art and may include, for example, additional connectors and solder balls, thermal interface material (TIM), additional chips on laminate 525, package lids, etc.

[0040] A damaged area 550 in the capillary underfill 505 of module 510A is illustrated by a solid line representing a sidewall delamination and a dashed line representing a crack propagating from the sidewall delamination into the bulk of the underfill 505. If the area 550 is not repaired, the crack may propagate further into the chip 520, the solder mask 530, the solder balls 540, etc. In the process 500, a thermal stimulus is applied to soften the bulk underfill 505, thereby re-healing the damaged area 550. The healed underfill 505 shown in module 510B may be cooled and thus re-solidified to be substantially free of the delamination and cracks of the damaged area 550.

[0041] In a profilometry measurement (not shown), a cracked film of TAGE-4160G was heated for about 30 minutes at 90° C. Profilometry before and after this re-healing cycle determined that the size of the cracks was reduced by about 99% (from 13 μm to about 180 nm).

[0042] The choice of amine curing agent can be used to tailor the properties of TAGE-amine. For example, the amount of softening in response to a thermal stimulus can vary. This can be demonstrated using DMA to measure the change in storage modulus. Experimental DMA results were obtained while applying a thermal stimulus to two example TAGE-amine films. One example film was formed using Stycast B as the amine curing agent ("TAGE-StyB"), and the other example film was formed using 4160B as the amine curing agent ("TAGE-4160B"). The thermal stimulus was applied by heating each film from 25°C to 120°C (5°C / min). When TAGE-StyB was subjected to a thermal stimulus, its storage modulus changed from 80 MPa to 11 MPa (86% softening). When TAGE-4160B was subjected to a thermal stimulus, its storage modulus changed from 447 MPa to 18 MPa (96% softening).

[0043] In some embodiments, cured TAGE-amine films and materials / composites containing TAGE-amine can be removed from a substrate using a mixture of a protic solvent and an amine catalyst (referred to herein as a "depolymerization mixture"). Examples of protic solvents that can be used can include methanol, ethanol, isopropanol, glycerol, and the like. In some embodiments, the depolymerization mixture can include an amine catalyst such as triethylamine (TEA) or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The depolymerization mixture can be reacted with the TAGE-amine with heating in a solvent such as N-methylpyrrolidone (NMP). In one example experiment, a TAGE-StyB film was removed by treating the film with a depolymerization mixture of methanol and TEA (e.g., about 16 wt.% TEA) in NMP at 50 to 60°C. In another example experiment, TAGE-StyB films were removed by treating the films with a depolymerizing mixture of glycerol and DBU (eg, about 2 wt.% DBU) at 175° C. for 20 to 30 minutes.

[0044] 6 is a schematic diagram illustrating a process 600 for repairing a multi-chip module 603 ("module 603") by reworking an epoxy-based material containing TAGE-amine, according to some embodiments of the present invention. In operation 605, it may be determined that module 603 contains a defective chip 606 (indicated by a "x" in FIG. 6) and a properly functioning chip 609 (indicated by a check mark in FIG. 6). Both chips 606 and 609 are connected to laminate 623 by layers of underfill 616 and 619 and solder balls (represented by grey spheres).

[0045] The defective chip 606 may be removed from the laminate 623. This is shown in operation 625. The underfill 616 under the defective chip may be a TAGE-amine and filler composite (e.g., TAGE-StyB with 50 to 60 wt.% about 1 μm SiO2 particle filler). The underfill 616 may be treated with a solution / bath containing a solvent / amine depolymerization mixture (e.g., methanol / TEA, glycerol / DBU, etc.) such as those discussed above. Additionally, heat may be applied while treating the underfill 616, as discussed above. After depolymerization of the underfill 616, the defective chip 606 may be removed from the module 603.

[0046] After removal, a residue 629 may remain on the laminate 623. This residue 629 may contain TAGE-amine, filler particles, etc. However, removal of the residue 629 may be accomplished by further treatment with a depolymerization mixture, heat or solvent washing, or a combination thereof. This is shown in operation 635. In other embodiments, no residue may remain after removal of the defective chip 606. In these cases, the cleaning process in operation 635 may optionally be omitted.

[0047] After removal of the defective chip 606, a new chip 636 may be connected to the module 603. This is shown in operation 645. The new chip 636 may be connected with solder balls (grey spheres in FIG. 6) using any suitable technique known in the art. A new layer of capillary underfill 646 may then be added underneath the new chip 636 to surround the solder balls. This is shown in operation 655. In some embodiments, the new underfill layer 639 is a TAGE-amine composite. In these cases, if the new chip 636 fails in the future, the process 600 may be repeated. However, any suitable capillary underfill may be used. In operation 655, it may be determined that the new chip 636 and the remaining original chips 609 are functional (indicated by a check mark).

[0048] In some embodiments, a rework / depolymerization process such as process 600 can be performed on a multi-chip module having three or more chips. However, the protic solvent / amine depolymerization process to remove the chips can be used on any suitable packaged module that includes a TAGE-amine underfill. In further embodiments, the depolymerization process can be used to remove TAGE-amine materials other than the underfill (e.g., TIM, adhesives, etc.).

[0049] The description of various embodiments of the present invention is presented for illustrative purposes, but is not intended to be exhaustive or limited to the described embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope of the described embodiments. The terms used in this specification are selected to best explain the principles of the embodiments, practical applications, or technical improvements over the art found in the market, or to allow those skilled in the art to understand the embodiments described herein.

Claims

1. 1. A composition comprising a polymer formed by reacting an epoxy compound with an amine curing agent, the epoxy compound comprising: Diels-Alder Dimer, and Ester moiety A composition comprising:

2. The composition of claim 1 further comprising filler particles.

3. 3. The composition of claim 2, wherein the filler particles are 40 to 60 wt. % of the composition.

4. The composition of claim 1, wherein the amine curing agent is selected from the group consisting of 4,7,10-trioxatridecane-1,13-diamine and 4,4-methylenebis(2-ethylaniline).

5. The composition of claim 1 , wherein the polymer is depolymerized by treatment with a solution comprising an amine and a protic solvent.

6. The composition of claim 1 , wherein the epoxy compound is Thiele acid glycidyl ether.

7. 2. The composition of claim 1, wherein the Diels-Alder dimer portion comprises cyclopentadiene.

8. 2. The composition of claim 1, wherein the Diels-Alder dimer moiety undergoes reverse dimerization at a temperature of about 30° C. or greater.

9. The composition of claim 1 further comprising a radical inhibitor.

10. 1. A method comprising: providing a polymer formed by reacting an amine curing agent and an epoxy compound, the epoxy compound comprising: Diels-Alder Dimer, and Ester moiety A method comprising:

11. 11. The method of claim 10, further comprising providing a composite material containing the polymer and about 40 to 60 wt. % filler particles.

12. The method of claim 11 , wherein the composite material is selected from the group consisting of capillary underfill and thermal interface material.

13. The method of claim 10 , wherein the polymer is removable from the substrate by treatment with a solution comprising an amine and a protic solvent.

14. The method of claim 10 further comprising providing an electronic package comprising the polymer.

15. The method of claim 10, wherein the polymer is re-recoverable at a temperature of approximately 30° C. or greater.

16. The method of claim 10 further comprising mixing the polymer with a radical inhibitor.

17. A device comprising a material, the material comprising a composition according to any one of claims 1 to 9.

18. 20. The device of claim 17, wherein the material is selected from the group consisting of capillary underfill and thermal interface materials.

19. 20. The device of claim 17 which is a multi-chip module.

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