METHOD FOR PRODUCING A DISTORTIONED CONTACT HILL CONNECTION STRUCTURE

Abstract

Method comprising the following steps: Determining positions for first electrical connectors (112, 214) of a first package component (100, 200) and for second electrical connectors (112, 214) of a second package component (100, 200), wherein the first electrical connectors (112, 214) and the second electrical connectors (112, 214) having the same positions are electrical connector pairs (112, 214); Determining estimated offset values ​​of the first and second electrical connectors (112, 214) in response to a melting process for bonding the first package component (100, 200) to the second package component (100, 200);Calculating offset values ​​for each of the electrical connection element pairs (112, 214) based on the estimated offset values, wherein for each of the electrical connection element pairs (112, 214) a corresponding offset value is calculated which is smaller than the corresponding estimated offset value, wherein the offset value for an electrical connection element pair (112, 214) specifies a displacement of the electrical connection element pair (112, 214) prior to the melting process for bonding the first package component (100, 200) to the second package component (100, 200); Modifying the positions of the first and second electrical connection elements (112, 214) to produce modified designs, wherein the positions of the first and second electrical connection elements (112, 214) in the same electrical connection element pairs (112, 214) are shifted from each other by the offset values;Manufacturing the first package component (100, 200) and the second package component (100, 200), wherein the first and second electrical connecting elements (112, 214) have the modified designs; and performing the melting process to bond the first package component (100, 200) to the second package component (100, 200).

Description

background Integrated circuit packages can contain multiple package components bonded together. Recent application developments have led to the fabrication of high-performance computing (HPC) packages, which typically feature very large package substrates and interposers. These substrates and interposers can have multiple layers. Combined with the significant structural and material differences between the substrate and interposer, and their large size, this resulted in a significant differential in thermal expansion between the substrate and the package components above it. This could lead to problems such as cold solder joints and bridging. DE 10 2013 019 277 A1 discloses an integrated circuit with a package and offset interconnects. US 2020 / 0 098 714 A1 discloses elongated bonded structures for a substrate and a package. Summary The present invention relates to a method according to claim 1. Claims 2 to 7 describe particularly advantageous implementations of the method according to claim 1. Brief description of the drawings Aspects of the present invention are best understood with reference to the detailed description below in conjunction with the accompanying drawings. It should be noted that, in accordance with common industry practice, various elements are not drawn to scale. Rather, for the sake of clarity of discussion, the dimensions of the various elements may be arbitrarily enlarged or reduced. Fig. 1 shows a first design of a first package component and a second package component, which, according to some embodiments, are to be bonded together. Figs. 2A and 2B show an expected misalignment of electrical connectors in the first package component and electrical connectors in the second package component in response to a melting process in some embodiments. Figs. 3A and 3B show a sectional view and a cross-sectional view, respectively.Figure 4A and Figure 4B show a sectional view and a top view, respectively, of an offset of electrical connectors in the first and second package components after a melting process according to some embodiments. Figure 5 shows an example of a heterogeneous package according to some embodiments. Figure 6 shows a top view of a pair of electrical connectors and a solder area on an outer side wall of an electrical connector according to some embodiments. Figure 7 shows a process flow for designing and manufacturing a package according to some embodiments. Detailed description The invention is defined by independent claim 1, which defines a method, independent claim 8, which defines a structure, and independent claim 15, which defines a structure. Embodiments of the invention are defined by the dependent claims. The following description provides many different embodiments or examples for implementing various features of the invention. Specific examples of components and arrangements are described below to simplify the present invention.For example, the fabrication of a first element over or on a second element in the following description may include embodiments in which the first and second elements are fabricated in direct contact, and it may also include embodiments in which additional elements can be fabricated between the first and second elements, so that the first and second elements are not in direct contact. Furthermore, reference numerals and / or letters may be repeated in the various examples in the present invention. This repetition serves for simplicity and clarity and does not in itself imply any relationship between the various embodiments and / or configurations discussed. According to some embodiments, a package with electrical connectors, which has offsets between the bonded electrical connectors, and a method for its fabrication are provided. In one exemplary method for fabricating the package, the expected offset values ​​between first electrical connectors in a first package component and second electrical connectors in a second package component are first determined. Some of the offset values ​​are provided as pre-offset values, and designs of the first and / or second package component are revised such that the first electrical connectors are pre-offset relative to the corresponding second electrical connectors. The "pre-offset" is so named because it occurs before the melting process for bonding the first and second package components together.Since the pre-displacement values ​​are smaller than the corresponding expected offset values, after the melting process the first electrical connectors of the first package component and the corresponding second electrical connectors of the second package component are still offset, which can help reduce mechanical stresses in soldered areas. For all connected first and second electrical connectors, the distance of the first electrical connector from a die center axis should be greater than the distance of the second electrical connector. Accordingly, solder covers part of one side of the first electrical connector in a contact bump distortion structure to reduce stress.The present invention ensures improved CPI reliability (CPI: Chip-Package Interaction) that is better than that of contact bumps without distortion, since a larger solder volume on the high-voltage side can effectively reduce the stress to prevent contact bump breakage. The embodiments discussed herein are intended to provide examples to enable the manufacture or use of the subject matter of the present invention, and a person skilled in the art should readily recognize modifications that may be made within the intended scope of protection of other embodiments. In all illustrations and explanatory embodiments, similar reference numerals are used to denote similar elements. While some method embodiments may be discussed as being carried out in a particular sequence, other method embodiments may be carried out in any logical sequence. Figures 1, 2A, 2B, 3A, 3B, 4A, and 4B show sectional and top views of intermediate stages in the design and manufacture of a package according to some embodiments of the present invention. The corresponding steps are also schematically indicated in the process flow 400 shown in Figure 7. Fig. 1 shows a sectional view of package components according to some embodiments. The package components comprise a package component 100 and a package component 200, which are to be bonded together by solder bonding. It is understood that the package components 100 and 200 can be physical components that have already been manufactured or designs of these package components that have not yet been manufactured. In some embodiments of the present invention, the package components 100 and 200 are bonded together to create a high-performance computing (HPC) package that can be used in applications requiring high performance, such as in AI (artificial intelligence) applications. In some embodiments, the package component 100 is (or comprises) a package substrate, which may be a cored or coreless package substrate. The package component 100 may also be or comprise a printed circuit board, a package, or the like. If the package component 100 is or comprises a cored package substrate, it has a core 102 comprising a core dielectric 104, conductive traces 106 penetrating the core dielectric 104, and a dielectric filler 108 within the conductive traces 106. In some embodiments, the core dielectric 104 is made of one or more materials from the group consisting of epoxy, resin, glass fiber, prepreg (comprising an epoxy, a resin, and / or a glass fiber), glass, molding compound, and plastic, a combination thereof, and multilayers thereof.Distribution lines (DSLs) 110 are manufactured in dielectric layers 111 and are electrically connected to each other via the conductive lines 106. In some embodiments, the DSLs 110 are made of or incorporate copper, aluminum, titanium, nickel, gold, or the like, alloys thereof, or multilayers thereof. Electrical connectors 112 are fabricated on a top surface of the package component 100. In some embodiments, the electrical connectors 112 are bond pads. A dielectric layer 114 can be fabricated to cover peripheral portions of the electrical connectors 112 when the electrical connectors 112 are bond pads. Central portions of the electrical connectors 112 are exposed through openings in the dielectric layer 114. In alternative embodiments, the electrical connectors 112 are metal contact mounds that project above a top surface of the dielectric layer 114. The metal contact mounds can be made of copper and may (or may not) include layers made of one or more metals or metal alloys containing nickel, palladium, or the like.The dielectric layer 114 can be made from a solder mask or from polymers such as polybenzoxazole (PBO), a polyimide, benzocyclobutene (BCB), or the like. In some embodiments, solder areas (hereinafter also referred to as solder contact mounds) 116 are prefabricated for connection to the electrical connecting elements 112. The solder areas 116 are therefore hereinafter referred to as pre-solder areas 116. In some embodiments, electrical connection elements 120 are produced on an underside of the package component 100 and are electrically connected to the electrical connection elements 112 via the conductive lines 106 and the RDLs 110. A dielectric layer 122 can mask edge portions of the electrical connection elements 120. Solder areas 124 are produced to connect them to the electrical connection elements 120. In alternative embodiments, the package component 100 is a coreless package component that has no core but a plurality of redistribution lines (similar to the RDLs 110) that are made in a plurality of dielectric layers. Furthermore, a package component 200 is fabricated for bonding to the package component 100. In some embodiments, the package component 200 is (or comprises) an interposer, which may be a semiconductor interposer, an organic interposer, or the like. If the interposer is a semiconductor interposer, it may have a semiconductor substrate, such as a silicon substrate, and vias (occasionally referred to as silicon vias) penetrating the semiconductor substrate. On opposite sides of the semiconductor substrate, dielectric layers, metal conductors, and vias are fabricated, which are interconnected by the vias. The dielectric layers may be made of or comprise a low-k dielectric, silicon oxide, silicon nitride, silicon oxide nitride, or the like.If the package component 200 is an organic interposer, as schematically depicted in Fig. 1, it can have a plurality of dielectric layers 202 and redistribution lines 204 within the dielectric layers 202. In some embodiments, the dielectric layers 202 are made of organic materials such as a polyimide, PBO, BCB, or the like. In some embodiments, the package component 200 has electrical connecting elements 214, which may include sub-contact-bump metallizations (UBMs) 212 and conductive contact bumps 210. The UBMs 212 may have an adhesive layer, such as a titanium layer, a copper layer, or a composite layer with a copper layer on top of the titanium layer. The conductive contact bumps 210 may be made of copper, nickel, palladium, gold, combinations thereof, and multilayers thereof. Solder areas 216 may be formed on the electrical connecting elements 214. In some embodiments, the solder areas 216 may not extend onto the sidewalls of the electrical connecting elements 214. In some embodiments, one or more package components 300 are bonded to the package component 200 by solder areas 224. The package components 300 can comprise one or more packages manufactured by a packaging process, and the packages can include logic dies, such as compute dies, memory dies, such as DRAM dies (DRAM: dynamic random-access memory) or SRAM dies (SRAM: static random-access memory), photonic dies, packages (comprising device dies that have already been capped), I / O dies, digital dies, analog dies, passive surface-mount devices, or the like. The dies in the package components 300 can be encapsulated in one or more capping materials, such as a molding compound, a backfill, an epoxy, a resin, or the like.In some embodiments of the present invention, the package components 300 comprise a system-on-chip (SoC) die, which is a package with device dies bonded together to form a system. The package components 300 may also comprise HBM stacks (HBM: high-bandwidth memory), wherein the HBM stacks each comprise a plurality of memory dies stacked on top of each other to form the memory stack. The memory dies may be DRAM dies, SRAM dies, or other types of memory dies. In some embodiments, one of the electrical connectors 214 is aligned with a central axis C100 of the package component 100, and this electrical connector 214 is referred to below as a central electrical connector 214. The central axis of the package component 200 may be aligned vertically with the central axis C100 or may be offset from it. There may be a package component 300 that has an electrical connector 214 which is electrically connected to the electrical connector 214. In alternative embodiments, there is no electrical connector 214 and / or no package component 300 aligned with the central axis C100. The package component 300 that is aligned with the central axis C100 is shown with dashed lines to indicate that it may or may not be present. In some embodiments, in initial designs of package components 100 and 200, the positions of the electrical connectors 214 are designed to be uniquely aligned with the corresponding electrical connectors 112. Throughout this description, the electrical connectors 112 and their corresponding electrical connectors 214 are to be bonded together, and they are collectively referred to as an electrical connector pair 112 / 214. Accordingly, package components 100 and 200 have a plurality of electrical connector pairs. Throughout this description, when used for electrical connectors, the terms "correspond" and "correspond" refer to electrical connectors that form a pair consisting of the electrical connector 112 and the electrical connector 214, which are to be bonded together.In other words, the electrical connecting elements 112 and 214 in the same pair are "corresponding" electrical connecting elements. Furthermore, the central axes of the electrical connecting elements 112 and 214 in the same pair of electrical connecting elements are referred to below as "corresponding" central axes. In the initial designs, the central axes 213 of the electrical connecting elements 214 are vertically and uniquely aligned with the central axes 113 of the corresponding electrical connecting elements 112. In the description, the term "corresponding" can be used interchangeably with the term "respective". When package components 100 and 200 are provided, the positions of each of the electrical connection element pairs 112 / 214 are first determined, for example by recording their x and y coordinates (as shown in Fig. 2B). The corresponding step is specified as step 402 in process flow 400, which is shown in Fig. 7. Fig. 2A shows the bonding of package component 200 to package component 100 by a melting process in which solder areas 116 and 216 (Fig. 1) are melted to create solder areas 16. This forms a package 10. In some embodiments, the coefficient of thermal expansion (CTE) CTE100 of package component 100 is greater than the total CTE CTE200 of package component 200 and the total CTE CTE300 of package component 300. For example, package component 100 may have a total CTE of about 12 ppm / K to about 20 ppm / K, and the total CTE CTE200 of package component 200 and the total CTE CTE300 of package component 300 may be about 3 ppm / K to about 10 ppm / K.It is understood that in the exemplary embodiments shown, it is assumed that CTE100 is, for example, larger than CTE200, while in other embodiments CTE100 may also be smaller than CTE200, and the principles of the present invention apply here as well. During the melting process, both package components 100 and 200 expand, and the electrical connecting elements 112 and 214 are laterally further away from the central axis C100 of package component 100 than before the melting process. Since CTE100 is larger than CTE200 in the exemplary embodiments, package component 100 expands more than package component 200. The central axes 113 of the electrical connecting elements 112 are therefore offset outwards (away from the central axis C100) from the corresponding central axes 213 with offset values ​​ΔS (which include ΔS1, ΔS2, etc.).It is understood that the offset values ​​ΔS are related to the positions of the corresponding connecting elements 112 and 214, and the further away from the central axis C100 the electrical connecting elements 112 and 214 are located, the higher the offset values ​​ΔS. For example, in Fig. 2, ΔS2 is greater than ΔS1. If there is a central electrical connecting element pair 112 / 214 on the central axis C100, then it is to be expected that the central axes 113 and 213 of the central electrical connecting element pair 112 / 214 have no offset. The offset value ΔS of each of the electrical connection element pairs 112 / 214 is then determined. The corresponding step is specified as step 404 in the process flow 400 shown in Fig. 7. The offset values ​​ΔS each have a component in the x-directions (Fig. 2B) and a component in the y-directions. Some of the offset values ​​ΔS may have the same magnitude, but when considering the directions +x, -x, +y, and -y, all offset values ​​are different from one another, since offset values ​​of the same magnitude have different directions. In some embodiments, the package components 100 and 200 are manufactured as physical package components, and therefore a real melting process is carried out, and the offset values ​​ΔS are determined by measurement on the already manufactured package 10. In alternative embodiments, the package components 100 and 200 are designs and have not yet been manufactured.Accordingly, the package 10 is simulated, and the offset values ​​ΔS of the electrical connection element pairs 112 / 214 are determined by simulation. For example, the materials, structures, and sizes of the package components 100 and 200 are used as input parameters for the simulation. Furthermore, the sizes and positions of the electrical connection element pairs 112 / 214 (such as their distances from the central axis C100) are also used in the simulation to determine the offset values ​​ΔS. In some embodiments, the package 10 includes the package component 300, and the offset values ​​ΔS are also influenced by the CTEs of package component 300. In alternative embodiments, the package 10 includes the package component 200 but not the package component 300. Accordingly, the offset values ​​ΔS are not influenced by the CTEs of package component 300. Fig. 2B shows a top view of the package 10 shown in Fig. 2A. For differentiation, in Fig. 2B and in subsequent figures, the electrical connecting elements 112 are shown, for example, with hexagonal top-view shapes, while the electrical connecting elements 214 are shown, for example, with circular top-view shapes. The electrical connecting elements 112 and 214 can also have other top-view shapes, including circles, hexagons, rectangles, ovals, octagons, etc. In some embodiments, the package components 100 and 200 are essentially homogeneous, meaning that the structural elements in different parts of the packages have similar properties, such as CTEs. Accordingly, the electrical connecting elements 112 are offset outwards from the respective bonded electrical connecting elements 214 in directions away from the central axis C100.In other words, in an electrical connection element pair 112 / 214, after melting, the corresponding central axes 213 and 113 can be aligned in a straight line extending from the central axis C100 to the central axes 213 and 113, and the central axis 113 is further away from the central axis C100 than the corresponding central axis 213. The displacement of the central axes 113 from the corresponding central axes 213 thus occurs in a radius structure, with the central axis C100 being the central axis of the radius structure. Furthermore, the offset values ​​ΔS of the electrical connecting element pairs 112 / 214 can be proportional to their distances from the central axis C100. For example, in Fig. 2B, a ratio ΔS2 / S2 is equal to a ratio ΔS1 / S1 and is equal to ratios ΔS3 / S3 and ΔS4 / S4. In some embodiments, the offset value ΔS of an electrical connecting element pair 112 / 214 can be determined from Equation 1 as follows: where S is the distance of the electrical connecting element pair 112 / 214 from the central axis C100 and ΔS is the offset value of the electrical connecting element pair 112 / 214 after remelting. The value TempR (with the unit "K") is an index that can be related to the temperature at which the solder areas 16 begin to resolidify after remelting. Based on the determined offset values ​​ΔS of the electrical connection element pairs 112 / 214, package component 100 and / or package component 200 are redesigned, and the positions of the electrical connection elements 112 and / or 214 are modified. Fig. 3A shows a sectional view of the redesigned package components 100 and 200. For example, the positions of the electrical connection elements 112 and 214 in the same electrical connection element pair are offset relative to each other by offset values ​​pre-S (which include pre-S1, pre-S2, etc.). The offset values ​​pre-S also each have components in the x-directions (in the +x and -x directions) and components in the y-directions (in the +y and -y directions), as shown in Fig. 3B. The term "pre-shift" indicates that a shift exists and is generated before the melting process for bonding the package components 100 and 200. First, the pre-separation value pre-S is determined for each of the electrical connection element pairs 112 / 214. The corresponding step is specified as step 406 in the process sequence 400 shown in Fig. 7. In some embodiments, the package components 100 and 200 are essentially homogeneous. As explained above and shown in Fig. 2B, the offset values ​​ΔS are therefore proportional to the distances of the corresponding electrical connection element pairs 112 / 214 from the central axis C100. The pre-separation values ​​pre-S are calculated as a part of the determined offset values ​​ΔS. For example, the following equation can be used to determine the pre-separation values ​​pre-S: where A is a pre-separation factor less than 1.0, ranging from approximately 0.5 to approximately 0.7. The significance of the pre-separation factor A is discussed in later paragraphs.The fact that the displacement factor A is less than 1 means that the displacement value is smaller than the corresponding offset value ΔS. It follows that, because the offset value ΔS has components in the directions +x / -x and +y / -y, the displacement values ​​pre-S also have components in the directions +x / -x and +y / -y. Accordingly, the displacement values ​​pre-S encompass not only the magnitude of the displacement but also its directions. Instead of keeping the pre-shift values ​​pre-S proportional to the offset values, in alternative embodiments the pre-shift values ​​pre-S are calculated such that post-melting offset values ​​post-M (Fig. 4A and Fig. 4B) can have a fixed predetermined value, which can be approximately 1 / 5 to approximately 1 / 4 of a critical dimension W1 (Fig. 4B) of the electrical connecting elements 214. Accordingly, the following equation is used to determine the pre-shift values ​​pre-S: It is understood that equation 3 applies to an electrical connection element pair 112 / 214 whose offset values ​​ΔS are equal to or greater than the specified value. For an electrical connection element pair 112 / 214 whose offset values ​​ΔS are less than the specified value, the forward offset values ​​of the corresponding electrical connection element pair 112 / 214 can be set to zero (no forward offset). Once the offset value for each of the electrical connector pairs 112 / 214 has been determined, the package components 100 and 200 are redesigned, and the positions of the electrical connectors 112 and / or 214 are modified to implement the offset values. The corresponding step is specified as step 408 in process flow 400, which is shown in Fig. 7. The corresponding package components 100 and 200 with the modified designs are shown in Fig. 3A and Fig. 3B. In some embodiments, the package component 100 is redesigned, and the positions of the electrical connectors 112 are modified, such that the center axes 113 of the electrical connectors 112 are shifted by the corresponding offset value pre-S relative to the center axis C100.This causes the central axes 113 of the electrical connecting elements 112 to be laterally spaced from the corresponding central axis 213 by the offset values ​​pre-S (which include pre-S1, pre-S2, etc.). In alternative embodiments, the package component 200 is redesigned such that the central axes 213 of the electrical connecting elements 214 with the offset values ​​pre-S (which include pre-S1, pre-S2, etc.) are displaced away from the central axis C100. This also laterally distances the central axes 213 of the electrical connecting elements 214 with the offset values ​​pre-S1, pre-S2, etc., from the central axes 113 of the corresponding electrical connecting elements 112. In further alternative embodiments, the package components 100 and 200 are redesigned to implement the offset values ​​pre-S, ΔS1, ΔS2, etc. It is understood that in the structure shown in Fig. 3A, the package component 200 is merely placed on the package component 100 and has not yet been bonded to the package component 100 by a melting process. Fig. 3B shows a two-dimensional representation (for example, a top view) of the redesigned package components 100 and 200 and the positions of the electrical connecting elements 112 and 214 according to some embodiments. Assuming that the central axis C100 of package component 100 and the central axis of package component 200 are aligned with each other (overlapping), the central axes 113 of the electrical connecting elements 112 are shifted forward relative to the central axis C100 and the central axis 213 of the corresponding electrical connecting elements 214. In some embodiments, all electrical connection pairs 112 / 214 in the package components 100 and 200 are forward-shifted. However, if there is an electrical connection pair 112 / 214 directly on the central axis C100, no forward shift is performed on the central electrical connection pair 112 / 214. In alternative embodiments, the package component 100 has a central region 130 that contains the central axis C100. The central region 130 can also be symmetrical about the central axis C100. For example, the central region 130 can be a rectangular region whose width and length are less than approximately 25% (or approximately 20%) of the corresponding width and length of the package component 100.The central region 130 can also be a circular region centered on the central axis C100, the diameter of which is less than approximately 25% (or approximately 20%) of the larger of the width and length of the package component 100. In some embodiments, none of the electrical connection pairs 112 / 214 within the central region 130 are pre-shifted, while all electrical connection pairs 112 / 214 outside the central region 130 are pre-shifted. The reason the electrical connection pairs 112 / 214 are not pre-shifted in the central region 130 is that the offset values ​​ΔS in the central region 130 are too small to cause problems such as cold solder joints and bridging.In contrast, the fact that the electrical connecting element pairs 112 / 214 are not pre-displaced in the central area 130 can advantageously lead to the corresponding solder areas having larger post-displacement values ​​(which will be discussed in later paragraphs) and thus makes it more likely that the solder areas 16 will climb up the outer side walls of the electrical connecting elements 214. The redesigned package components, shown in Figures 3A and 3B, are then manufactured as physical components. This step is designated as step 410 in process flow 400, shown in Figure 7. Subsequently, the manufactured package components 100 and 200 are bonded together using a melting process. This step is designated as step 412 in process flow 400, shown in Figure 7. A resulting package 10' is shown in Figures 4A and 4B, which depict a sectional and a top view, respectively. The melting temperature is related to the material of the respective solder areas 216 and 116 (see Figure 3A) and can range from approximately 220 °C to approximately 255 °C. After the melting process, the temperature of package 10' is lowered, and the resulting solder areas 16, which include the melted solder areas 216 and 116, are solidified. Fig. 4A and Fig.Figure 4B shows the structure after solidification, for example when the package is 10' at room temperature (for example, about 19 °C to about 23 °C). The pre-displacement factor A of equation 2 is less than 1.0, which means that the pre-displacement values ​​pre-S (Fig. 2A and Fig. 2B) of the electrical connection pairs 112 / 214 are smaller than the offset values ​​ΔS (Fig. 3A and Fig. 3B) of the corresponding electrical connection pairs 112 / 214 and are therefore not large enough to compensate for these offset values ​​ΔS. As a result, as shown in Fig. 4A, after the melting process the central axes 113 are offset from the corresponding central axes 213. Furthermore, the central axis 113 is displaced beyond the corresponding central axis 213, towards an outer side (a side furthest from the central axis C100) of the corresponding central axis 213. In other words, the central axes 113 are farther from the central axis C100 than the corresponding central axis 213.Throughout this description, offset values ​​between the center axes 113 and 213 in the same electrical connection element pair 112 / 214 are referred to as post-melting offset values, designated post-M (specifically post-M1, post-M2, etc.). Again, the post-melting offset values ​​post-M each have a component in the +x or -x direction and a component in the +y or -y direction (Fig. 4B). As shown in Fig. 4A, the post-melting offset values ​​post-M can differ for different electrical connection element pairs 112 / 214. For example, the post-melting offset value post-M2 is larger than the post-melting offset value post-M1. Since the central axes 113 lie on the outer sides of the corresponding central axis 213, the solder regions 16 can climb up the outer side walls (the side walls facing away from the central axis C100) of the electrical connecting elements 214. However, no solder regions 16 climb up the inner side walls (the side walls facing the central axis C100) of the electrical connecting elements 214. In the top view shown in Fig. 4B, the outer side walls and the corresponding inner side walls are opposite each other and aligned with the line connecting the central axis C100 to the corresponding pair of electrical connecting elements 112 / 214. The formation of solder regions on the outer side walls, but not on the inner side walls, of the electrical connecting elements 214 has the advantage of reducing mechanical stress in the solder region 16 and the electrical connecting elements 112 and 214.The reason for this is that the outer surfaces of the electrical connecting elements 214 have higher stress values ​​than the respective inner surfaces, and increasing the solder volume on the outer surface can reduce the higher stress and help protect the solder area 16 and the electrical connecting elements 112 and 214 against cracking, delamination, etc. After the melting process, an underfill 18 is injected between package components 100 and 200. The underfill 18 is in contact with the inner sidewalls of the electrical connectors 214 and is separated from the outer sidewalls of the electrical connectors 214 by the solder area 16. Additionally, an underfill 20 can be distributed between package components 200 and 300. Fig. 6 shows a top view of an electrical connection element pair 112 / 214 according to some embodiments. For clarity, Fig. 6 shows the portions of the solder area 16 that are on the same plane (the plane considered in Fig. 4A) as the electrical connection element 214, while the portion of the solder area vertically between the electrical connection element 214 and the electrical connection element 112 below it (Fig. 4A) is not shown in Fig. 6. Fig. 6 shows that the solder area 16 is located on the outer side wall of the electrical connection element 214, which faces away from the central axis C100, while the inner side wall of the electrical connection element 214, which faces the central axis C100, does not have the solder area 16. Fig. 4B shows a two-dimensional representation (for example, a top view) of the package 10' shown in Fig. 4A. In some embodiments, the central axes 113 are displaced away from the central axis C100 with respect to their corresponding central axes 213. The post-melt dislocation has a radius structure, which means that the central axes 113 and 213 of each of the electrical connector pairs 112 / 214 can be aligned to form a straight line connecting the central axis C100 to the electrical connector pair 112 / 214. As shown in Fig. 4B, the pre-shift values ​​pre-S and the post-melting offset values ​​post-M each have a component in the x-direction and a component in the y-direction, and the components in the x-direction and the components in the y-direction together form the corresponding pre-shift values ​​pre-S and the corresponding post-melting offset values ​​post-M. As explained above and shown in Fig. 2B, in some embodiments the offset values ​​ΔS are proportional to the distances S of the corresponding electrical connection element pairs 112 / 214 from the central axis C100. Furthermore, the pre-displacement values ​​pre-S are equal to the offset values ​​ΔS multiplied by the pre-displacement factor A. Accordingly, the post-melting offset values ​​post-M can be equal to (1 - A) · ΔS, and they can also be proportional to the distances S of the corresponding electrical connection element pairs 112 / 214 from the central axis C100. If A is, for example, about 0.5 to 0.7, then the post-melting offset values ​​post-M are about 0.3 to 0.5 times the offset values ​​ΔS. In alternative embodiments where Equation 3 is used to calculate the pre-S offset values, the resulting post-M melting offset values ​​are the same for different electrical connector pairs 112 / 214, regardless of whether they have the same or different distances from the central axis C100. For example, except for the electrical connector pairs 112 / 214 whose offset values ​​ΔS are smaller than the specified post-M value (Equation 3), all electrical connector pairs 112 / 214 shown in Fig. 4B may be of the same size and may or may not be oriented in the same directions. Since these electrical connector pairs 112 / 214 [which can determine where region 130 (Fig. 3B) is located] cannot be pre-shifted, their post-M melting offset values ​​are equal to their offset values ​​ΔS. In other words, in area 130 (Fig.3B) All electrical connection element pairs 112 / 214 have post-melting offset values ​​post-M that are proportional to their distance from the central axis C100 and equal to their corresponding offset values ​​ΔS. Outside the area 130, however, all electrical connection element pairs 112 / 214 have the same post-melting offset values ​​post-M, which are equal to the specified post-M value (equation 3). The calculation of the offset values ​​ΔS and the resulting post-melting offset values ​​post-M can also be presented differently, as follows. In some embodiments discussed in the preceding paragraphs, after the offset values ​​ΔS have been determined, either experimentally using physical packages or by simulation, the offset values ​​ΔS are presented as two parts. One part is the pre-offset value pre-S, which is equal to A · ΔS. The other part is a target post-adjustment value post-M. Experimental results have shown that the post-adjustment value post-M must lie within a certain range. If the post-adjustment value post-M is too high, there is a risk of cold solder joints (no connection) in solder areas or unwanted bridging of solder areas with adjacent electrical connection elements.If the post-adjustment value (post-M) is too low, the reduction of mechanical stress in soldered areas will be insufficient. Therefore, the post-melt offset values ​​(post-M) of the electrical connector pairs 112 / 214 located in the outermost corners are designed to be approximately 1 / 5 to approximately 1 / 4 of the critical dimension (CD) (also shown as width W1 in Fig. 4B) of the electrical connectors 214 (Fig. 4A). Since the electrical connector pairs 112 / 214 located in the outermost corners are closest to the corners of the package component 100 and are thus subject to greater mechanical stress than other electrical connector pairs, using post-melt offset values ​​(post-M) of the electrical connector pairs 112 / 214 located in the outermost corners in the range of 1 / 5(W1) to 1 / 4(W1) maximizes the benefits and minimizes the problems. In the embodiments discussed above, the package 10' is substantially homogeneous, meaning that the CTE values ​​of different parts of the package components 100 and 200 are very close to each other, for example, with a deviation of less than about 10% of the CTEs of the respective package components 100 and 200. For example, if one or more package components 200 cover substantially the entire package component 100 and the materials and structures of the package components 100 and 200 are uniform, the package 10' is homogeneous. Accordingly, the pre-shift values ​​pre-S and the post-melt offset values ​​post-M can be calculated based on the distances between the electrical connection element pairs 112 / 214 and the CTEs CTE100 and CTE200. In other embodiments, the package 10' is heterogeneous. Fig.Figure 5 shows, for example, a package 10' with a package component 200 that covers part, but not all, of the package component 100, such that a significant portion (for example, more than 20% or 30%) of the package component 100 is not covered by the package component 200. Furthermore, the package component 200 is significantly offset from the central axis of the package component 100. Accordingly, the portion of the package 10' that includes the package component 200 has a different CTE than the portion of the package 10' that does not include the package component 200. In these embodiments, the manufacturing of the packages may comprise the following steps. First, the positions of the electrical connection element pairs 112 / 214 in the resulting package are determined, corresponding to the structure of Fig. 1, unless the package components 100 and 200 are heterogeneous. Then, a simulation is performed using finite element modeling. The structure, materials, and melting conditions are used as input parameters in the model. The offset values ​​ΔS (comprising the components in the x and y directions) of each of the electrical connection element pairs 112 / 214 are determined. In these embodiments, the offset cannot have a propagation pattern from the central axis C100. Then, based on the offset values ​​ΔS, the pre-displacement value pre-S for each of the electrical connection element pairs 112 / 214 is calculated.The calculation involves determining the target post-melt offset values ​​(post-M) and subtracting these values ​​from the simulated offset values ​​(ΔS) to generate pre-shift values ​​(pre-S, encompassing components in the x and y directions) for each of the electrical connection element pairs 112 / 214. After the pre-shift values ​​have been calculated, package component 100 and / or package component 200 are redesigned to implement the calculated pre-shift values. The redesigned package components 100 and 200 can then be fabricated and bonded together by melting. In the embodiments described above, some methods and structural elements according to some embodiments of the present invention for fabricating a three-dimensional package (3D package) are discussed. Other structural elements and methods can also be used. For example, test structures can be used to assist in the verification testing of a 3D encapsulation or 3DIC devices. The test structures can, for example, include test pads fabricated in a redistribution layer or on a substrate, enabling the testing of the 3D encapsulation or 3DIC devices, the use of probes and / or probe cards, and the like. The verification testing can be performed on intermediate structures as well as on final structures.Furthermore, the structures and procedures disclosed here can be used in conjunction with testing methodologies that include intermediate verification of proven good dies to increase yield and reduce costs. In the exemplary embodiments discussed, the CTE100 of package component 100 is larger than the CTE200 of package component 200. It is understood that the embodiments of the present invention can also apply to situations in which the CTE100 of package component 100 is smaller than the CTE200 of package component 200. The processes are similar to those discussed above, except that in these embodiments, the electrical connecting elements 112 are displaced away from the central axis C100 relative to the electrical connecting elements 214, and the post-melting displacement of the electrical connecting elements 112 towards the central axis C100 occurs relative to the corresponding electrical connecting elements 214. The embodiments of the present invention have several advantages. By determining the pre-displacement values ​​and the post-melting offset values, the mechanical stress applied to the solder areas / contact mounds can be reduced, and the problem of cold solder joints and the problem of bridging can also be mitigated. In some embodiments of the present invention, a method comprises the following steps: determining positions for first electrical connectors of a first package component and for second electrical connectors of a second package component, wherein the first electrical connectors and the second electrical connectors, which have the same positions, are electrical connector pairs; determining offset values ​​of the first and second electrical connectors in response to melting processes for bonding the first package component to the second package component; calculating forward offset values ​​for each of the electrical connector pairs based on the offset values; modifying the positions of the first and second electrical connectors to produce modified designs.wherein the positions of the first and second electrical connectors in the same electrical connector pairs are shifted from each other by the pre-shift values; fabricating the first and second package components, wherein the first and second electrical connectors have the modified designs; and performing a melting process to bond the first package component to the second package component. In one embodiment, a corresponding pre-shift value is calculated for each of the electrical connector pairs, which is less than a corresponding offset value. In one embodiment, after the melting process, the first electrical connectors are offset by a post-melt offset value of corresponding second electrical connectors in the same electrical connector pairs. In one embodiment, the post-melt offset value is in a rangewhich is greater than 1 / 5 of the width of the first electrical connectors and less than 1 / 4 of the width. In one embodiment, prior to the melting process, the first electrical connectors are closer to a central axis of the first package component than corresponding second electrical connectors in the same pairs of electrical connectors.After the melting process, the first electrical connectors are located further from the central axis of the first package component than the corresponding second electrical connectors in the same pairs. In one embodiment, the first electrical connectors are displaced from or to the central axis of the first package component relative to the corresponding second electrical connectors in the same pairs. In one embodiment, the first package component has a higher coefficient of thermal expansion than the second package component.wherein the first electrical connecting elements are displaced relative to the central axis of the first package component with respect to the corresponding second electrical connecting elements in the same pairs of connecting elements. In one embodiment, the forward displacement values ​​are calculated as the product of the offset values ​​and an index, where the index is greater than 0 and less than 1. In some embodiments of the present invention, a structure comprises: a first package component with a first electrical connector; a second package component with a second electrical connector; a first solder contact mound connecting the first electrical connector to the second electrical connector, wherein a first central axis of the first electrical connector is offset from a second central axis of the second electrical connector by a first post-melt offset value; a third electrical connector in the first package component; a fourth electrical connector in the second package component.wherein the third electrical connector and the fourth electrical connector are closer to a further central axis of the first package component than the first and second electrical connectors, and a third central axis of the third electrical connector is offset from a fourth central axis of the fourth electrical connector by a second post-melt offset value that is smaller than the first post-melt offset value; and a second solder contact mound connecting the third electrical connector to the fourth electrical connector. In one embodiment, the first electrical connector projects beyond a surface of the first package component, wherein the first electrical connector has: a first side wall that faces away from a central axis of the first package component,wherein the first solder contact mound contacts the first side wall; and a second side wall that points to the central axis of the first package component, wherein the first solder contact mound is spaced from the second side wall. In one embodiment, the structure further includes an underfill between the first package component and the second package component, wherein the underfill contacts the second side wall of the first electrical connector. In one embodiment, the first post-melt offset value is in a range of about 1 / 5 to about 1 / 4 of a critical dimension of the first electrical connector. In one embodiment, the first central axis is offset from the second central axis in a directionwhich extends from the further central axis of the first package component to the first central axis. In one embodiment, the first package component has a higher coefficient of thermal expansion than the second package component, wherein the first central axis is located further from the further central axis of the first package component than the second central axis. In one embodiment, a first ratio of the first post-melting offset value to a first distance is equal to a second ratio of the second post-melting offset value to a second distance, wherein the first distance is a distance between the first electrical connecting element and the further central axis, and the second distance is a distance between the third electrical connecting element and the further central axis. According to some embodiments of the present invention, a structure comprises: a first package component with a first conductive pad; a second package component above the first package component, the second package component having a dielectric surface layer and a first conductive contact mound projecting lower than the dielectric surface layer, the first conductive contact mound having a first side wall pointing away from a central axis of the first package component and a second side wall pointing towards the central axis; a solder contact mound connecting the first conductive pad to the first conductive contact mound, the solder contact mound contacting the first side wall; and an underfill between the first package component and the second package component, the underfill contacting the second side wall.In one embodiment, a first central axis of the first conductive pad, with a first post-melt offset value, is located further from the central axis of the first package component than a second central axis of the first conductive contact mound. In another embodiment, the structure further comprises a second conductive pad in the first package component and a second conductive contact mound in the second package component, wherein the second conductive pad and the second conductive contact mound are closer to the central axis of the first package component than the first conductive pad and the first conductive contact mound, and a third central axis of the second conductive pad, with a second post-melt offset value that is smaller than the first post-melt offset value, is offset from a fourth central axis of the second conductive contact mound.In one embodiment, the first post-melting offset value is approximately 20% to approximately 25% of a critical dimension of the first conductive contact mound. In another embodiment, the second package component has a higher coefficient of thermal expansion than the first package component.

Claims

Method comprising the following steps: Determining positions for first electrical connectors (112, 214) of a first package component (100, 200) and for second electrical connectors (112, 214) of a second package component (100, 200), wherein the first electrical connectors (112, 214) and the second electrical connectors (112, 214) having the same positions are electrical connector pairs (112, 214); Determining estimated offset values ​​of the first and second electrical connectors (112, 214) in response to a melting process for bonding the first package component (100, 200) to the second package component (100, 200);Calculating offset values ​​for each of the electrical connection element pairs (112, 214) based on the estimated offset values, wherein for each of the electrical connection element pairs (112, 214) a corresponding offset value is calculated which is smaller than the corresponding estimated offset value, wherein the offset value for an electrical connection element pair (112, 214) specifies a displacement of the electrical connection element pair (112, 214) prior to the melting process for bonding the first package component (100, 200) to the second package component (100, 200); Modifying the positions of the first and second electrical connection elements (112, 214) to produce modified designs, wherein the positions of the first and second electrical connection elements (112, 214) in the same electrical connection element pairs (112, 214) are shifted from each other by the offset values;Manufacturing the first package component (100, 200) and the second package component (100, 200), wherein the first and second electrical connecting elements (112, 214) have the modified designs; and performing the melting process to bond the first package component (100, 200) to the second package component (100, 200). Method according to claim 1, wherein after the melting process the first electrical connecting elements (112, 214) are offset by a post-melting offset value of corresponding second electrical connecting elements (112, 214) in the same connecting element pairs (112, 214). Method according to claim 2, wherein the post-melting offset value is in a range (130) that is greater than 1 / 5 of the width of the first electrical connecting elements (112, 214) and less than 1 / 4 of the width. Method according to one of the preceding claims, wherein before the melting process the first electrical connecting elements (112, 214) are closer to a center of the first package component (100, 200) than corresponding second electrical connecting elements (112, 214) in the same electrical connecting element pairs (112, 214) and after the melting process the first electrical connecting elements (112, 214) are further away from the center of the first package component (100, 200) than the corresponding second electrical connecting elements (112, 214) in the same electrical connecting element pairs (112, 214). Method according to one of the preceding claims, wherein in the modified designs the first electrical connecting elements (112, 214) are displaced from or to a center of the first package component (100, 200) in relation to corresponding second electrical connecting elements (112, 214) in the same pairs of connecting elements (112, 214). Method according to claim 5, wherein the first package component (100, 200) has a higher coefficient of thermal expansion than the second package component (100, 200), wherein the first electrical connecting elements (112, 214) are displaced towards the center of the first package component (100, 200) in relation to the corresponding second electrical connecting elements (112, 214) in the same electrical connecting element pairs (112, 214). Method according to one of the preceding claims, wherein the offset values ​​are calculated as products of the estimated offset values ​​and an index, wherein the index is greater than 0 and less than 1.

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