Semiconductor package with die mounting system and method for manufacturing a semiconductor package

Abstract

Semiconductor package (100) comprising: a semiconductor die (102); a substrate (104) for supporting the semiconductor die (102); an encapsulant (106) covering the semiconductor die (102) and at least a portion of the substrate (104); and a die attach material (108) that contacts and attaches the semiconductor die (102) to the substrate (104), the die attach material (108) comprising molecules having a first functional group with at least one lone pair of electrons and a second functional group that has or can react chemically with the encapsulant (106) in a manner that promotes adhesion to the encapsulant (106).

Description

[0001] The present application relates to semiconductor dies, in particular to systems and methods for attaching semiconductor dies to a substrate.

[0002] Semiconductor dies are often attached to a substrate such as a lead frame, printed circuit board (PCB), etc. using a die attach paste such as adhesive paste, solder paste, or sintering paste. With thinner semiconductor dies, creep of the die attach paste to the top surface becomes more likely, which can lead to electrical failure. In addition to avoiding such creep, acceptable wetting between the backside of the die and the substrate is also important. Wetting refers to the flow of die attach material along horizontal x and y directions of the substrate. The better the wetting, the easier the die attach process and the higher the probability of achieving a high level of die attach reliability during stress testing.Strong adhesion to an encapsulation material such as a mold composition surrounding the semiconductor die is another important consideration, particularly at the top of the die and at the internal leads before and after performing reliability stress tests.

[0003] Standard die attach processes that use conventional adhesive pastes, solder pastes, and sintering pastes, especially for thin dies, must be carefully metered to avoid creep of the die attach material to the top surface of the die during the die attach process. Standard die attach films can be used instead of pastes, and creep is not an issue. However, compared to adhesive pastes, solder pastes, and sintering pastes, die attach films are more expensive and have lower thermal and electrical performance. Another challenge is avoiding voids.

[0004] US 2004 / 0 075 161 A1 describes a method for attaching a silicon die to a metallic leadframe. The leadframe is coated with triazine or isocyanurate, and the silicon die is attached to the leadframe using an adhesive containing epoxy, acrylate, or bismaleide. The composition is then cured. Then, terminals of the chip are connected to terminals of the leadframe, and an encapsulation is applied and cured. Triazine or isocyanurate contain nitrogen with pairs of free electrons, and functional groups that can react with a resin bonded to the leadframe and form a chemical bond.

[0005] From US 2003 / 0 083 452 A1, compositions are known which contain at least one epoxy functionality and at least one vinylsilane functionality.

[0006] US 2017 / 0 005 062 A1 relates to the production of a film for bonding a die. The composition used to produce the film may contain a polymer component, a thermosetting component, a filler, an adhesion promoter, a crosslinking agent, a photopolymerization initiator, and general additives. The thermosetting component may contain an epoxy compound, a thermosetting agent, and a curing accelerator.

[0007] A molded semiconductor package known from US 2016 / 0 282 212 A1 includes a substrate having opposing first and second main surfaces, a semiconductor die attached to the first main surface, an adhesion adapter attached to the second main surface or to a surface of the semiconductor die facing away from the substrate, and a molding compound that encapsulates the semiconductor die, the adhesion adapter, and at least a portion of the substrate. The adhesion adapter is configured to adapt adhesion properties of the molding compound to adhesion properties of the substrate or the semiconductor die such that the molding compound adheres more strongly to the adhesion adapter than directly to the substrate or the semiconductor die.

[0008] From US 2015 / 0 155 267 A1 an electronic chip is known whose thickness - plus the chip attachment material - is 150 µm.

[0009] There is a need for a cost-effective die attachment system with good wettability to the substrate and good adhesion to the encapsulation material.

[0010] According to one embodiment of a semiconductor package, the semiconductor package comprises: a semiconductor die; a substrate for supporting the semiconductor die; an encapsulant covering the semiconductor die and at least a portion of the substrate; and a die attach material contacting and attaching the semiconductor die to the substrate. The die attach material comprises molecules having a first functional group with at least one lone pair of electrons and a second functional group that has chemically reacted or can react with the encapsulant in a manner that promotes adhesion to the encapsulant.

[0011] According to one embodiment of a method for manufacturing a semiconductor package, the method comprises: applying a die attach material to the substrate, the die attach material comprising molecules having a first functional group with at least one lone pair of electrons and a second functional group; placing a semiconductor die on the attach material; covering the semiconductor die and at least a portion of the substrate with an encapsulating material; and processing the substrate with the semiconductor die and the encapsulating material at an elevated temperature to cure the encapsulating material, solidify the die attach material, and chemically react the second functional group of at least some of the molecules with a precursor of the encapsulating material in a manner that promotes adhesion to the encapsulating material as the encapsulating material cures.

[0012] Those skilled in the art will recognize additional features and advantages upon reading the following detailed description and examining the accompanying drawings.

[0013] The elements of the drawings are not necessarily to scale relative to one another. Like reference numerals designate corresponding similar parts. The features of the various embodiments shown may be combined with one another, provided they are not mutually exclusive. Embodiments are illustrated in the drawings, and they are described in detail in the following description.

[0014] Fig. 1 shows a partial cross-sectional view of an embodiment of a semiconductor package with a multifunctional die attach material.

[0015] Fig. 2 shows a drawing of the Fig. 1 semiconductor packages shown from top to bottom.

[0016] Fig. 3 shows a partial cross-sectional view of another embodiment of a semiconductor package with a multifunctional die attach material.

[0017] The Fig. 4A to 4C show an embodiment of a method for producing the Fig. 1 to 3 shown semiconductor packages.

[0018] The embodiments described herein provide a semiconductor die attach system that avoids creep of the die attach material onto the top surface of the semiconductor die, has good wettability between the backside of the die and the substrate, and has increased adhesion to an encapsulant material covering the semiconductor die.

[0019] Fig. 1 shows a partial cross-sectional view of a semiconductor package 100. The semiconductor package 100 can be leadless or leaded. Leaded packages have legs or leads around the perimeter of the package that either extend through a PCB or other type of substrate and are soldered to the back of the substrate (through-hole), or directly to the front of the substrate (surface mount). Leadless packages save space by having contact points below the package rather than at the perimeter. In any case, the semiconductor package 100 can have any standard configuration, such as, but not limited to, through-hole, surface mount, chip carrier, pin grid array, ball grid array, multi-die package, etc.

[0020] The semiconductor package 100 includes a semiconductor die 102, a substrate 104 for supporting the semiconductor die 102, an encapsulant 106 covering the semiconductor die 102 and at least a portion of the substrate 104, and a die attach material 108 attaching the semiconductor die 102 to the substrate 104. For ease of illustration, Fig. 1 shows a semiconductor die 102.

[0021] Fig. 2 shows a top-down plan view of the semiconductor package without the encapsulant 106, so that the semiconductor die 102, the substrate 104, and the die attach material 108 are visible in the top-down plan view.

[0022] The die attach material 108 may include electrically conductive fillers such as Ag, Cu, etc. for electrically coupling an electrode on the backside 110 of the semiconductor die 102, such as a drain or collector electrode of a transistor or an anode or cathode electrode of a diode, to an electrically conductive portion of the substrate 104. For example, the die 102 may have a ground electrode on the backside 110 that is electrically connected to a corresponding ground trace of the substrate 104. Additionally or alternatively, the die attach material 108 may include thermally conductive fillers such as silicon oxide (silica), aluminum oxide (alumina), boron nitride, etc. for thermally coupling the backside 110 of the semiconductor die 102 to the substrate 104. In yet another embodiment, the die attach material 108 may be free of electrically and thermally conductive fillers.Electrical connections 113 may be provided between the substrate 104 and one or more electrodes on the top side 112 of the semiconductor die 102, e.g., by bonding wires, metal clips, metal ribbons, etc.

[0023] In general, the semiconductor package 100 may include one or more semiconductor dies 102 attached to the substrate 104. Any type of semiconductor die may be used, such as, but not limited to, logic dies, power transistor dies, power diode dies, memory dies, sensor dies, passive semiconductor dies such as capacitor and / or inductor dies, etc. The semiconductor die 102 may be made of any type of semiconductor material, including, but not limited to, single-element semiconductors (e.g., Si, Ge, etc.), silicon-on-insulator semiconductors, binary semiconductors (e.g., SiC, GaN, GaAs, etc.), ternary semiconductors, etc., with or without epitaxial layer(s). The semiconductor die 102 may be a lateral die, in which the main current path of the device is lateral near the top surface 112 of the die 102.For devices without vertical current flow, metallization on the backside 110 of the semiconductor die 102 may be omitted. The semiconductor die 102 may instead be a vertical die, in which the main current path between the top and bottom sides 110, 112 of the die 102 is vertical. The semiconductor die 102 may include a single device, such as a single power transistor or diode, or it may include more than one device. For example, power and logic devices may be integrated into the semiconductor die 102. Other die types, configurations, and semiconductor material systems are also contemplated.

[0024] Regardless of the type of semiconductor die 102, the die 102 may have a standard thickness 't', e.g., 700 micrometers thick, 800 micrometers thick, or even thicker. Instead, the semiconductor die 102 may be relatively thin, e.g., having a thickness 't' of less than 500 micrometers. In some cases, the semiconductor die 102 is ultra-thin, e.g., having a thickness 't' in a range of 50 micrometers to 100 micrometers, e.g., 20 micrometers to 300 micrometers, e.g., 50 micrometers to 150 micrometers. In any case, the die attach material 108 does not extend to the top side 112 of the semiconductor die 102, i.e., the surface facing away from the substrate 104.

[0025] The substrate 104 supports the semiconductor die 102. Any standard substrate type may be used, such as, but not limited to, a metal lead frame, a printed circuit board (PCB), a flexible substrate, a ceramic with metallized surfaces such as a DBC (direct copper bonded) substrate, an AMB (active metal brazed) substrate, an IMS (insulated metal substrate), or other types of substrates for supporting semiconductor dies.

[0026] Regardless of the type of substrate, the attach material 108 attaches the semiconductor die 102 to the substrate 104. The attach material 108 comprises organic molecules having a first functional group with at least one lone pair of electrons and a second functional group that has reacted, or is capable of reacting (i.e., capable of chemically reacting) with the encapsulant 106 in a manner that promotes adhesion to the encapsulant 106. Because the die attach material 108 has some non-negligible thickness, not every molecule of the die attach material 108 reacts with the encapsulant 106 during the manufacturing process. Therefore, the second functional groups of some of the molecules remain reactive with the encapsulant 106 after the manufacturing process and would therefore promote adhesion to the encapsulant 106 if they reacted with the encapsulant 106.Any standard semiconductor die encapsulant such as, but not limited to, epoxy mold compounds, laminate films, silicone glop tops, etc. may be used.

[0027] The bottom side 110 of the semiconductor die 102 has a metal / metal alloy or metal oxide surface. High reactivity / affinity between the metal / metal alloy or metal oxide bottom side 110 of the semiconductor die 102 and the die attach surface 114 of the substrate 104, which typically comprises metal or a metal alloy, is realized by ensuring that the first functional group of the molecules of the die attach material 108 has at least one lone pair of electrons. For example, if the substrate 104 is a lead frame, the die attach surface 114 may be a die pad. In another example, if the substrate 104 is a ceramic-based package, the die attach surface 114 may be a die pad patterned into a metallized surface of a ceramic.In yet another example, if the substrate 104 is a PCB, the die attach surface 114 may be a metal conductive trace patterned into a metal sheet. In each case and others, free electron functionalities are separated by interaction with the metal / metal alloy die attach surface 114 of the substrate 104. This results in a good reaction with the metallized die attach surface 114 of the substrate 104 through electron exchange, which ensures good wetting and adhesion of the metallized die attach surface 114. With such a high reactivity / affinity between the bottom side 110 of the semiconductor die 102 and the die attach surface 114 of the substrate 102, the die attach material 104 has good wetting of the substrate 104, i.e.it spreads well in both horizontal directions x and y, but it spreads less in the vertical direction z along the edge 116 of the semiconductor die 102. For example, the die attach material 108 may have a fillet 118 that creeps up the edge 116 of the semiconductor die 102 and has a creep height 'c' preferably < 50% of the thickness 't'.

[0028] The thickness 'b' of the die attach material 108 beneath the semiconductor die 102 is typically not uniform. Also, the creep height 'c' is typically higher than the center of the edge 116 compared to the die corner, and is thus a function of the distance from the corner. The creep height 'c' depends on the thickness 'b' of the die attach material 108 beneath the semiconductor die 102 and the die width 'a'. According to one embodiment, the total creep height 'c' for 0 <= x <= a / 2 is given by c(x, b, a) < t. The following are example value ranges for the creep height 'c' and the parameters that affect the creep height 'c': a = 0.5 - 10 mm; A (total die area) = 0.25 - 100 mm 2 , e.g. 1 - 25 mm 2 ; t = 20 - 450 µm, e.g. B. 50 - 300 µm; b = 5 - 80 µm, e.g. B. 10 - 40 µm; c = 5 - 90% t, e.g. B. 10 - 50% t.

[0029] The groove 118 in conjunction with the horizontal spreading 's', e.g., 50-1000 µm, caused by the first functional group of the die attach material molecules, results in good adhesion to the substrate 104, and the second functional group of the die attach material molecules results in good adhesion to the encapsulant 106.

[0030] In one embodiment, the first functional group of the die attach material molecules is an amino acid group. In another embodiment, the first functional group of the die attach material molecules is an amine group. In yet another embodiment, the functional group of the die attach material molecules is a silane group. In yet another embodiment, the first functional group of the die attach material group is a sulfur group.

[0031] The second functional group of the organic molecules of the die attach material 108 is selected to be chemically reactive with the encapsulant 106 during the manufacturing process to enhance adhesion between the die attach material 108 and the encapsulant 106 when the base material system for the encapsulant 106 undergoes a curing process. For example, the second functional group of at least some of the molecules of the die attach material 108 reacts with a precursor, such as a curing agent, such as unreacted epoxy functional groups of an epoxy-based encapsulant, in a manner that promotes adhesion to the encapsulant as the encapsulant cures to form the encapsulant 106. In one embodiment, the second functional group of molecules of the die attach material 108 is an epoxy group.In another embodiment, the second functional group is a glycidyl ether group.

[0032] A die attach material comprising the above-described organic molecules having the first and second functional groups prevents creep of the die attach material 108 onto the top surface 112 of the semiconductor die 102, has good wettability between the backside 110 of the die 102 and the substrate 104, and has increased adhesion to the encapsulant 106 covering the semiconductor die 102. In one embodiment, the multifunctional molecules included in the die attach material 108 are bis-amino molecules. In another embodiment, the multifunctional molecules included in the die attach material 108 comprise 1,6-diaminohexane. In yet another embodiment, the multifunctional molecules included in the die attach material 108 are bis-epoxy molecules. In one case, the bis-epoxide molecules comprise 1,6-bis(2,3-epoxypropoxy)hexane (1,6-hexanediol diglycidyl ether).

[0033] In one embodiment, the first functional group of the molecules of the die attach material 108 is an amino group and the second functional group is an epoxy group. For example, the molecules may be 1-amino-6-hexaneol glycidyl ether molecules. In another embodiment, the first functional group of the molecules is an amino group and the second functional group is a silane group. In yet another embodiment, the first functional group of the molecules is an epoxy group and the second functional group is a silane group.

[0034] The multifunctional molecules of the die-bonding material 108 have a total weight percentage (wt%) in the range of 0.1 wt% to 20 wt%. In the case where the die-bonding material 108 has electrically conductive fillers such as Ag, Cu, etc. and / or thermally conductive fillers such as silicon oxide, aluminum oxide, boron nitride, etc., the multifunctional molecules of the die-bonding material 108 can have a total weight percentage of 2 wt% or less. If the die-bonding material 108 is free of electrically and thermally conductive additives, the multifunctional molecules of the die-bonding material can have a total weight percentage of 20 wt% or less, e.g., 10 wt% or less.

[0035] Fig. 3 shows a partial cross-sectional view of a semiconductor package 200 according to a further embodiment. The in Fig. The semiconductor package design shown in Figure 3 is similar to that shown in Fig. 1 and Fig. 2. Deviating from this, the semiconductor package 200 in Fig. 3, however, still a coating 302, which is applied to the semiconductor die 102 and contacts the encapsulant 106. The electrical connections 113 between the substrate 104 and the die 102 are located in Fig. 3 are out of view, but they could also be coated by the coating 302 depending on when the coating 302 is applied. The coating 302 comprises the same multifunctional molecules as the die attach material 108 to promote adhesion to the encapsulant 106 around the semiconductor die 102. That is, the coating 302 comprises molecules having a first functional group with at least one lone pair of electrons and a second functional group that has reacted or can react with the encapsulant 106 in a manner that promotes adhesion to the encapsulant 106 around the semiconductor die 102. The coating 302 can be applied, for example, by spray coating, dip coating, lamination, chemical vapor deposition, liquid deposition, etc.applied to the entire structure after the die attach process or after the electrical connections 113 to the top side 112 of the semiconductor die 102 are formed. The coating 302 provides improved and reliable adhesion of the encapsulant 106 and any coated interfaces. Any of the multifunctional molecule / group types described above in conjunction with the chip attach material 108 may be included in the coating 302.

[0036] The Fig. 4A to 4C illustrate an embodiment of a method for producing the Fig. 1 to 3 shown semiconductor packages 100, 200.

[0037] In Fig. 4A, the die attach material 108 is applied to a substrate 104. The substrate 104 is of the type described above in connection with the Fig. 1 to 3. The die attachment material 108 comprises multifunctional molecules of the type also described above in connection with the Fig. 1 to 3. That is, the molecules have a first functional group with at least one lone pair of electrons and a second functional group that promotes adhesion to an encapsulant to be applied later. In one embodiment, the die attach material 108 is a solder paste applied to a die attach surface 114 of the substrate 104, wherein the solder paste comprises multifunctional molecules of the type explained above. In another embodiment, the die attach material 108 is a sintering paste applied to the die attach surface 114 of the substrate 104, wherein the sintering paste comprises multifunctional molecules of the type explained above. In yet another embodiment, the die attach material 108 is a laminate film applied to the die attach surface 114 of the substrate 104, the laminate film comprising multifunctional molecules of the type discussed above.In yet another embodiment, the die attach material 108 is an adhesive applied to the die attach surface 114 of the substrate 104, the adhesive comprising multifunctional molecules of the type discussed above.

[0038] In Fig. 4B, a semiconductor die 102 is placed on the die attach material 108, and electrical connections such as, but not limited to, bond wires, metal clips, metal ribbons, etc. are created between the substrate 104 and one or more electrodes on the top side 112 of the semiconductor die 102. The semiconductor die 102 is of the type described above in connection with the Fig. 1 to 3. According to this method, more than one semiconductor die can be attached to the substrate 104 by the die attach material 108. For ease of illustration, one semiconductor die 102 is shown.

[0039] In Fig. 4C, the semiconductor die 102 and at least a portion of the substrate 104 are covered with an encapsulating material 300. The encapsulating material 300 is the starting material used to form the semiconductor die described above in connection with the Fig. 1 to 3. For example, in the case of a mold compound or other type of epoxy-based encapsulating material, the encapsulating material 300 may include an epoxy and a precursor, such as unreacted epoxy functional groups, as a hardener.

[0040] The substrate 104 with the semiconductor die 102 and the encapsulating material 300 is then processed at an elevated temperature to cure the encapsulating material 300, solidify the die attach material 108, and chemically react the second functional group of at least some of the multifunctional molecules of the die attach material 108 with the precursor of the encapsulating material 300 in a manner that promotes adhesion to the encapsulating material 300 as the encapsulating material cures. In one embodiment, the elevated processing temperature is in a range of 125°C to 300°C, e.g., 150°C to 200°C. The multifunctional molecules contained in the die attachment material 108 have a good and stable affinity to metal surfaces and a high reactivity with the encapsulating material 300. Accordingly, the second group of multifunctional molecules bleeds out.: “bleed-out” and acts as an adhesion promoter between the metallized die attach surface 114 of the substrate 104 and the encapsulating material 300 when the encapsulating material 300 cures.

[0041] The Fig. The method shown in Figures 4A to 4C can be modified to Fig. 3 by applying a coating to the semiconductor die 102 and the substrate 104 before covering the semiconductor die 102 with the encapsulating material 300. The coating comprises the same multifunctional molecules as the encapsulating material 300 described above in connection with Fig.3. In this way, the second functional group of at least some of the coating molecules chemically reacts with the precursor of the encapsulating material 300 during elevated temperature processing in a manner that promotes adhesion to the encapsulating material 300 as the encapsulating material 300 cures.

[0042] Terms such as "first," "second," and the like are used to describe different elements, areas, sections, etc., and are not intended to be limiting. Like terms refer to like elements throughout the description.

[0043] The terms "comprising," "containing," "including," "comprising," and the like, as used herein, are open-ended terms that indicate the presence of specified elements or features, but do not preclude additional elements or features. The articles "a," "an," and "the" are intended to include plural as well as singular forms unless the context clearly indicates otherwise.

[0044] It is understood that the features of the various embodiments described herein may be combined with one another unless expressly stated otherwise.

[0045] Although specific embodiments have been illustrated and described herein, those skilled in the art will recognize that a variety of alternative and / or equivalent implementations may be substituted for the specific embodiments shown and described.

Claims

[1] Semiconductor package (100) comprising: a semiconductor die (102); a substrate (104) for supporting the semiconductor die (102); an encapsulant (106) covering the semiconductor die (102) and at least a portion of the substrate (104); and a die attach material (108) that contacts and attaches the semiconductor die (102) to the substrate (104), the die attach material (108) comprising molecules having a first functional group with at least one lone pair of electrons and a second functional group that has or can react chemically with the encapsulant (106) in a manner that promotes adhesion to the encapsulant (106). [2] Semiconductor package (100) according to claim 1, wherein the semiconductor die (102) has a thickness (t) in a range of 20 µm to 300 µm or 50 µm to 150 µm and wherein the die attachment material (108) does not extend onto a main surface (112) of the semiconductor die (102) facing away from the substrate (104). [3] Semiconductor package (100) according to claim 1 or 2, wherein the molecules are bis-amino molecules. [4] The semiconductor package (100) of claim 3, wherein the bis-amino molecules comprise 1,6-diaminohexane. [5] Semiconductor package (100) according to claim 1 or 2, wherein the molecules are bis-epoxide molecules. [6] The semiconductor package (100) of claim 5, wherein the bis-epoxide molecules comprise 1,6-bis(2,3-epoxypropoxy)hexane. [7] Semiconductor package (100) according to one of the preceding claims, wherein the first functional group of the molecules is one of the following: an epoxy group; an amine group; an amino acid group; a silane group; or a sulfur group. [8] Semiconductor package (100) according to one of the preceding claims, wherein the second functional group of the molecules is one of the following: an epoxy group, a glycidyl ether group; or a silane group. [9] Semiconductor package (100) according to one of claims 1 to 6, wherein the first functional group of the molecules is an amino group and the second functional group is an epoxy group. [10] The semiconductor package (100) of claim 9, wherein the molecules are 1-amino-6-hexanol glycidyl ether molecules. [11] The semiconductor package (100) according to any one of claims 1 to 6, wherein the first functional group of the molecules is an amino group and the second functional group is a silane group. [12] The semiconductor package (100) according to any one of claims 1 to 6, wherein the first functional group of the molecules is an epoxy group and the second functional group is a silane group. [13] Semiconductor package (100) according to one of the preceding claims, wherein the molecules have a total weight fraction in a range of 0.1 wt% to 20 wt%. [14] Semiconductor package (100) according to one of claims 1 to 13, wherein the die attachment material (108) comprises electrically and / or thermally conductive additives and wherein the molecules have a total weight fraction of 2 wt% or less. [15] Semiconductor package (100) according to one of claims 1 to 13, wherein the die attachment material (108) is free of electrically and thermally conductive additives and wherein the molecules have a total weight fraction of 10 wt% or less. [16] The semiconductor package (100) of any preceding claim, further comprising a coating (302) applied to the semiconductor die (102) and contacting the encapsulant (106), the coating (302) comprising the same molecules as the die attach material (108) in a manner that promotes adhesion to the encapsulant (106). [17] Semiconductor package (100) according to one of the preceding claims, wherein the semiconductor die (102) is one of the following: a power transistor die; a logic die; a sensor die; a memory die; a passive die; or a power diode die. [18] A method of manufacturing a semiconductor package (100), the method comprising: Applying a die attach material (108) to a substrate (104), the die attach material (108) comprising molecules having a first functional group with at least one lone pair of electrons and a second functional group; Placing a semiconductor die (102) on the die attachment material (108); Covering the semiconductor die (102) and at least a portion of the substrate (104) with an encapsulating material (106); and Processing the substrate (104) with the semiconductor die (102) and the encapsulating material (106) at an elevated temperature to cure the encapsulating material (106), solidify the die attach material (108), and chemically react the second functional group of at least some of the molecules with unreacted epoxy functional groups of the encapsulating material in a manner that promotes adhesion to the encapsulating material (106) as the encapsulating material (106) cures. [19] The method of claim 18, wherein applying the die attach material (108) to the substrate (104) comprises one of the following: Applying an adhesive to a die attach surface of the substrate (104), the adhesive comprising the molecules; Applying a solder paste to a die attach surface of the substrate (104), the solder paste comprising the molecules; Applying a sintering paste to a die attachment surface of the substrate (104), the sintering paste comprising the molecules; and Applying a laminate film to a die attach surface of the substrate (104), the laminate film comprising the molecules. [20] The method of claim 18 or 19, wherein the die attach material (108) comprises a solder, and wherein the solder with the molecules is applied to the substrate (104) prior to covering the semiconductor die (102) and at least a portion of the substrate (104) with the encapsulating material. [21] A method according to any one of claims 18 to 20, further comprising: Applying a coating (302) to the semiconductor die (102) before covering the semiconductor die (102) and at least a portion of the substrate (104) with the encapsulating material, wherein the coating (302) has the same molecules as the die attach material (108), wherein the second functional group of at least some of the molecules of the coating (302) chemically reacts with the precursor of the encapsulating material (106) during processing at the elevated temperature in a manner that promotes adhesion to the encapsulating material (106) as the encapsulating material (106) cures. [22] A process according to any one of claims 18 to 21, wherein the elevated temperature is in a range of 125°C to 300°C or 150°C to 200°C.

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