System and method for stress and distortion improvement of stiffening ring packages with exposed die(s)

Abstract

System (90) which includes the following: a package (100) that includes the following: a substrate (104) with a first surface (118); a die (116) with a first surface (121), a second surface (122) and a side surface, wherein the first surface (121) and the second surface (122) are opposite each other and the second surface of the die is connected to the first surface (118) of the substrate (104); a stiffening element (124) with a first surface (125), wherein the first surface (125) of the stiffening element (124) is connected to the first surface (118) of the substrate (104) via a first interface; and Molding compound (132) with a first molding surface (140) arranged in a continuous mold on the first surface (118) of the substrate (104) and on the side surface (136) of the die (116), wherein a coefficient of thermal expansion (CTE) value of the molding compound (132) is greater than a CTE value of the die (116); wherein the first mold surface (140) of the molding compound (132) is coplanar with the first surface (121) of the die (116); further comprising a heat sink (148) which is connected to the first surface (121) of the die (116) and the first mold surface (140).

Description

BACKGROUND

[0001] Semiconductor packages with exposed dies are susceptible to damage when connected to heat sinks and other components, leading to device failures in the form of die cracking and peeling, especially at the corners and edges of the die. To reduce the distortion of large packages (e.g., larger than 45 mm x 45 mm) with exposed dies, a stiffening ring is often applied to the circumference of the package substrate. However, stiffening ring packages are often prone to high tensile or strain stresses at the interface between the stiffening ring and the package substrate because the coefficients of thermal expansion (CTE) of the die, substrate, and stiffening ring do not match. During package production and use, this thermal stress interaction can lead to the initiation and propagation of cracks in the substrate at or near the interface with the stiffening ring.Furthermore, stiffening rings lose their effectiveness in reducing package warpage as the package size increases (for example, larger than 65 mm x 65 mm). Accordingly, it is desirable to provide a solution that reduces warpage and prevents package failures for these larger packages due to temperature changes during the manufacturing process and in field use. Document DE 10 2021 102 836 A1 discloses a package structure and a method for forming it. The method includes forming first electrical connections and second electrical connections on a first side of an interposer wafer. An integrated circuit die is bonded to the first side of the interposer wafer using the first electrical connections. A stiffening structure is attached to the first side of the interposer wafer adjacent to the integrated circuit die.The stiffening structure covers the second electrical connections in the top view. The integrated circuit die and the stiffening structure are encapsulated with a first encapsulation material. The interposer wafer and the stiffening structure are singulated into a stacked structure. Document US 2020 / 0058570A1 discloses a semiconductor packaging comprising a semiconductor chip with an active side, a redistribution layer over the active side of the semiconductor chip, wherein the redistribution layer includes metal traces that electrically connect chip pads on the active side of the semiconductor chip to electrical contacts on an outer surface of the semiconductor packaging, and a layer shape that covers the semiconductor chip opposite the redistribution layer.The layer configuration comprises a first resin layer adjacent to the redistribution layer, a fiber layer adjacent to the first resin layer and opposite the redistribution layer, and a second resin layer adjacent to the fiber layer and opposite the redistribution layer. Document US 6,002,171A discloses a multi-part integrated heat spreader / stiffener assembly that, after electrical connection of the chip to the substrate, is joined to the substrate and the chip in a semiconductor package, a packaging method using the integrated heat spreader / stiffener, and a semiconductor package containing the integrated heat spreader / stiffener.In a preferred embodiment, the integrated heat spreader / stiffening assembly consists of two parts, both made of a high-modulus, high-thermal-conductivity material, shaped to be attached to each other and to a chip on the surface of a housing substrate. Document US 2023 / 0063295A1 discloses a housing structure and a method for its fabrication. The housing structure comprises a housing substrate, a first chip, and a stiffening ring. The first chip is mounted on the housing substrate and has a first side wall and a second side wall facing each other. The stiffening ring is mounted on the housing substrate to surround the first chip. The stiffening ring has an inner wall facing the first chip, and the inner wall has at least one inclined side wall facing the first side wall of the first chip. SUMMARY

[0002] A system is disclosed. In embodiments, the system comprises a package further comprising a substrate with a first surface and a die (chip) with opposing first and second surfaces. In embodiments, the second surface of the die is connected to the first surface of the substrate. In embodiments, the system comprises a stiffener element with a first surface and a side surface, wherein the first surface of the stiffener element is connected to the first surface of the substrate at a first interface. In embodiments, the system comprises molding material arranged on the first surface of the substrate and the side surface of the die. In embodiments, the coefficient of thermal expansion (CTE) of the molding material is greater than the CTE of the die.

[0003] A method is disclosed. In embodiments, the method comprises providing a die having a first surface and a second surface opposite the first surface. In embodiments, the method comprises joining a die to a first surface of a substrate. In embodiments, the method comprises joining a first stiffening element to the first surface of the substrate. In embodiments, the method further comprises applying or arranging molding compound on the first surface of the substrate, on at least one lateral side of the stiffening element, and on at least one lateral surface of the die. In embodiments, a first molding surface of the molding compound is substantially flush with the first surface of the die.

[0004] This summary serves only as an introduction to the subject matter, which is fully described in the detailed description and the drawings. The summary is not to be considered a description of essential features, nor does it serve to determine the scope of the claims. Furthermore, both the preceding summary and the following detailed description are merely exemplary and explanatory, and not necessarily limiting, to the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The detailed description is explained with reference to the accompanying figures. The use of the same reference drawings at different points in the description and in the figures may indicate similar or identical elements. Various embodiments or examples (“Examples”) of the present disclosure are disclosed in the following detailed description and the accompanying drawings. The drawings are not necessarily to scale. In general, the operations of the disclosed methods may be carried out in any order, unless otherwise specified in the claims. In the drawings: Fig. 1A is a drawing showing a cutaway side view of a system containing electronic components, according to one or more embodiments of the disclosure; Fig. 1B is a drawing showing a cutaway side view of the package according to one or more embodiments of the disclosure; Fig. 1C is a drawing showing a top view of the package according to one or more embodiments of the disclosure; Fig. 1D is a drawing showing a cutaway side view of the package containing a heat sink in one or more embodiments of the disclosure; Fig. 2A is a drawing showing a top view of the package according to one or more embodiments of the disclosure; Fig. 2B is a drawing showing a cutaway side view of the package according to one or more embodiments of the disclosure; Fig. 2C is a drawing showing a top view of the package according to one or more embodiments of the disclosure; Fig. Figures 3A-B are flowcharts that depict a method for manufacturing the package in accordance with one or more embodiments of the disclosure. Fig. 4A-B are drawings showing a cutaway side view of the package according to one or more embodiments of the disclosure; Fig. Figures 5A-C are drawings showing a cutaway side view of a package containing a chip-on-wafer-on-substrate package according to one or more embodiments of the disclosure; Fig. Drawings 6A-C show a cutaway side view of the package according to one or more embodiments of the disclosure; Fig. Drawings 7A-B show a cutaway side view of the package with different molded parts according to one or more embodiments of the disclosure. DETAILED DESCRIPTION

[0006] Before one or more embodiments of the disclosure are explained in detail, it should be understood that the embodiments are not limited in their application to the design details and the arrangement of components, or the steps or methods set forth in the following description or illustrated in the drawings. Numerous specific details may be presented in the following detailed description of the embodiments to facilitate a more comprehensive understanding of the disclosure. However, it will be clear to a person skilled in the art who is familiar with the present disclosure that the embodiments disclosed herein can also be carried out without some of these specific details. In other cases, known features cannot be described in detail in order to avoid unnecessarily complicating the present disclosure.

[0007] As used here, a letter following a reference numeral is intended to indicate an embodiment of the feature or element that may be similar to, but not necessarily identical with, a previously described element or feature bearing the same reference numeral (for example, 1, 1a, 1b). Such abbreviations are for convenience only and are not to be construed as limiting the disclosure in any way, unless expressly stated otherwise.

[0008] Unless explicitly stated otherwise, "or" refers to an inclusive or and not an exclusive or. For example, a condition A or B is satisfied if any of the following conditions are true: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0009] Furthermore, the use of "a" or "an" may be employed to describe elements and components of the embodiments disclosed herein. This is done solely for the sake of simplicity, and "a" and "an" are intended to include "one" or "at least one," with the singular also including the plural unless it is obvious that something else is meant.

[0010] As used here, directional terms such as "above", "below", "over", "under", "upwards" and "downwards" serve to describe relative positions and not to designate an absolute frame of reference. Various modifications of the described embodiments are obvious to the person skilled in the art, and the general principles defined here can also be applied to other embodiments.

[0011] It is important to understand that, conceptually, any arrangement of components intended to achieve the same functionality, goal, objective, result, or structure is effectively "connected" or "coupled" such that the desired functionality, common goal, objective, result, or structure is achieved. Therefore, any two components combined here to achieve a specific structure can be considered "coupled" to achieve the desired structure and / or functionality, regardless of the architecture or intermediary components.Similarly, two components connected in this way can be considered "connected" or "arranged" to achieve the desired functionality, and two components that can be connected in this way can also be considered "coupleable" to achieve the desired structure or functionality (for example, "functionally coupled"). Unless otherwise specified, the description that a component is "connected" to another component or between two components means that these components are functionally connected and not necessarily that these components are in physical contact. Rather, such components may be in physical contact or, alternatively, contain intermediate elements. The description that a particular component is manufactured "over" another component (alternatively "situated on," "arranged on," etc.) is also used.The symbol indicates a relative position of these components, but does not necessarily mean that these components are physically in contact. Such components can be in physical contact or alternatively contain intermediate elements.

[0012] Finally, any reference to “an embodiment” or “some embodiments,” as used herein, means that a particular element, feature, structure, or property described in connection with the embodiment is included in at least one embodiment disclosed herein. The phrase “in some embodiments” at various points in the description does not necessarily refer to the same embodiment, and the embodiments may include one or more of the features expressly described herein or inherently present, or any combination of subcombinations of two or more such features together with other features not necessarily expressly described or inherently present in this disclosure.

[0013] An electronic package containing a substrate, a die, a stiffening element, and a molding compound is disclosed. The molding compound is applied to the package such that the top surface of the die is essentially flush or coplanar with the molding compound. The molding compound protects the die from cracking when the die is connected to other components of the package, such as a heat sink. The molding compound also reduces stresses in the substrate and distortion at the interface between the substrate and the stiffening element. The molding compound is formulated to have coefficients of thermal expansion (CTE) that minimize package distortion and substrate stresses.

[0014] Fig. Figure 1A is a drawing showing a cutaway side view of a system 90 containing a semiconductor chip with an integrated circuit (IC) and other electronic components according to one or more embodiments of the disclosure. The system 90 includes a package 100, also referred to as a semiconductor package, IC package, chip package, or electronic package. The package 100 organizes and provides the connectivity of the semiconductor chip (for example, integrated circuits) within the system 90. In some embodiments, the system 90 comprises only the package 100 and the semiconductor chip(s) within the package 100.

[0015] In embodiments, the package includes a substrate 104 configured to provide electrical connectivity and structural protection for the package elements. The substrate 104 can be of any type, including, but not limited to, an Ajinomoto build-up film (ABF) substrate, a BT (bismaleimide triazine) laminate substrate, a ceramic substrate, and the like. In embodiments, the system 90 further includes or is connected to a printed circuit board 108 (for example, a printed circuit board (PCB)). The printed circuit board 108 can itself be a component of a larger system that includes a user device, such as a mobile phone, smartwatch, gaming system, tablet, or computer.The substrate 104 can be connected to the printed circuit board 108 via solder balls 112 (for example, BGA balls) or another connection technology attached to a bottom surface (for example, a second surface 114) of the substrate 104. The substrate 104 can be configured for large packages. For example, the substrate 104 can have a dimension (for example, a length or a width) that is approximately equal to or greater than 45 mm. The substrate can, for example, have the approximate dimensions of a 45 mm x 45 mm square. In another example, the substrate can have a dimension that is approximately equal to or greater than 65 mm. Thus, the substrate can, for example, have the approximate dimensions of a 65 mm x 65 mm square.

[0016] In embodiments, the package 100 comprises at least one die 116 (for example, a semiconductor chip containing an integrated circuit) connected to a top surface (for example, a first surface 118) of the substrate 104. The die 116 comprises a first die surface 121 (for example, a first surface) and a second die surface 122 (for example, a second surface). The first die surface 121 and the second die surface 122 are opposite each other (for example, arranged opposite each other), with the second die surface 122 being connected to the first surface of the substrate 104. The die 116 can be configured as any type of semiconductor device(s), including, but not limited to, an IC chip, multiple semiconductor chips, a chip system in a packed module, integrated passive devices, or microelectromechanical systems (MEMS).The Die 116 can, for example, be configured as a chip on a TSV interposer (Through-Silicon-Via), as in the CoWoS package (Chip-on-Wafer-on-Substrate package or 2.5D package for integrated circuits) from Taiwan Semiconductor Manufacturing Company (TSMC).

[0017] The die 116 can be configured to connect to the substrate 104 via any type of connection element 120, including but not limited to flip-chip, surface-mount, or wire-mount package elements. For example, the die 116 can be configured to connect to the substrate 104 via a flip-chip die attachment method. The die 116 can be bound to the substrate 104 in any orientation or type of configuration. For example, the die 116 can be configured as a flip-chip and have flip-chip connections, also known as controlled collapse chip connections or C4. The flip-chip connections allow the die 116 to connect to the substrate 104 via solder bumps, copper pillars with solder caps, or other connection elements applied to connection pads on the die.In flip-chip assembly, the die 116 is flipped over, and the connecting elements 120 are aligned with the corresponding pads on the substrate 104. In this way, one side of the die 116, containing the integrated circuit, is oriented downwards as the second die surface 122, while the back of the die 116 is oriented upwards as the first die surface 121.

[0018] In some embodiments, the package further comprises a stiffening element 124. The stiffening element 124 has a first surface 125 which is connected to the first surface 118 of the substrate 104 via a stiffening adhesive 128 (for example, a first interface). The stiffening adhesive 128 may comprise a thermosetting resin / epoxy or another type of adhesive. The stiffening element 124 limits the deformation or distortion of the substrate 104 when the substrate 104 is heated (for example, by the heat generated during the manufacture of the package 100 or by the heat generated in the die 116 during use). Without the stiffening element 124, the substrate 104 can expand more than the die when its temperature rises due to the different coefficients of thermal expansion (CTE) between the two materials.This difference in the coefficients of thermal expansion (CTE) leads to differential expansion of the materials within the package, resulting in a warped appearance. This creates stresses on the die 116 and the substrate 104, potentially leading to cracks and failure of the die 116 or the substrate 104. Warping of the substrate 104 can also lead to improper connection of the package 100 to the printed circuit board 108, resulting in short circuits or open contacts. Connecting the stiffening element 124 to the substrate 104 partially reduces the warping of the substrate 104 and also dissipates heat from the substrate 104. The stiffening element 124 can be made of any type of material, including but not limited to metals such as copper, and can be of any size or shape. For example, the stiffening element 124 can be configured or shaped as a ring.The shape of the stiffening element 124 can also be configured as a cross, square, or rod, but is not limited to these. Furthermore, the stiffening element 124 can include cavities and / or slots to provide space for other surface-mountable components, such as capacitors, on the substrate surface 118 in the shadow of the first stiffening surface 125.

[0019] The CTE (coefficient of thermal expansion) is used to predict the linear expansion of a material when heated and can be determined using the following equation: WAKi=1xidxidT

[0020] X is X i the linear dimension (for example, a length or a width) of the material component i teand T is the temperature. CTE values ​​are usually given in ppm / °C. For a piece of copper one centimeter long, where copper has a CTE of approximately 16.6 ppm / °C, increasing the temperature of the copper from 0°C to 100°C would result in a predicted expansion of 1.67 µm of copper per 1 mm of length. The CTE of substrate 104, CTE Substrat , can be in the range of 10-17 ppm / °C. The CTE value of Dies 116, CTE Die , can range between 2-4 ppm / °C.

[0021] In embodiments, the stiffening element 124 has a CTE value, CTE Versteifungselement , similar to the WAK Substrat For example, the stiffening element 124 can have a CTE (coefficient of thermal expansion). Versteifungselement -value of approximately 16 ppm / °C, and substrate 104 can have a CTE Substrat -value in the range of approximately 16 ppm / °C (for example, within the range of 10-17 ppm / °C). In another example, the ratio between the CTE Versteifungselement -value and the WAKSubstrat -value equal to or less than 1.6. For example, the CAC Versteifungselement -value a value of approximately 16 ppm / °C and the CEC Substrat -value should have a value of approximately 10 ppm / °C (for example, WAK) Versteifungselement WAK Substrat is approximately 1.6). In another case, the ratio CAC is Versteifungselement WAK Substrat equal to or less than 1.4. In another case, the ratio of CTE Versteifungselement WAK Substrat equal to or less than 1.2. In another case, the ratio of CTE Versteifungselemen t:WAK Substrat equal to or less than 1.0.

[0022] It should be understood that the CTE values ​​described here represent CTE values ​​at temperatures below the glass transition temperature (Tg). g ) for package components. For example, for a substrate 104 with a T g of 130°C the WAK used here Substrat -value a WAK SubstratThe value is for a temperature of less than 130°C. For example, the WAK used here Substrat -value for substrate 104 a CEK Substrat The value can be for a temperature within the range of 0°C to 120°C, 0°C to 100°C, 10°C to 100°C, 20°C to 100°C, 22°C (for example, room temperature) to 100°C, 30°C to 80°C, or 50°C to 70°C. In particular, the CTE can Substrat -value for the substrate used here 104 a CTE Substrat -Value for a temperature of approximately 0°C, approximately 20°C, approximately 22°C, approximately 25°C (for example, room temperature) or approximately 100°C.

[0023] Fig. Figure 1B is a drawing showing a cutaway side view of the package 100 according to one or more embodiments of the disclosure. In embodiments, the package 100 further comprises molding compound 132, which is applied or arranged both on the first surface 118 of the substrate 104 and on at least one lateral die surface 136 (for example, a lateral surface of the die 116). The molding compound 132 can be arranged in continuous form, as a single body, on the first surface 118 of the substrate 104 and on at least one lateral die surface 136 of the die 116. For example, a continuous line of molding compound 132 can be applied to the package 100, which contacts both the first surface 118 of the substrate 104 and a lateral die surface 136 of the die 116.In another example, a block of molding compound 132 can be applied to the package 100, contacting both the first surface 118 of the substrate 104 and a lateral die surface 136 of the die 116. For example, the block of molding compound 132 can have several openings or holes (for example, where the die 116 or other components of the package pass through the molding compound 132, or spaces where the first surface 118 of the substrate 104 is not covered), with a continuous portion of molding compound 132 connecting the first surface 118 of the substrate 104 to at least one lateral die surface 136 of the die 116. In addition to the continuous form or single body of the molding compound 132, which is arranged on the first surface 118 of the substrate 104 and the at least one lateral surface 136 of the die 116, the molding compound 132 can also be arranged on other parts of the package 104 in a continuous or discontinuous manner.

[0024] In embodiments, the molding compound 132 substantially covers the entirety of the lateral die surfaces 136 of the die 116, and a first molding surface 140 of the molding compound 132 (for example, a top surface of the molding compound) is substantially flush or coplanar with the first die surface 121 of the die. For example, the first molding surface 140 and the first die surface 121 may be within 1 mm of each other. In another example, the first molding surface 140 and the first die surface 121 may be within 1.0 mm of each other. In another example, the first molding surface 140 and the first die surface 121 may be within 0.1 mm of each other. In yet another example, the first molding surface 140 and the first die surface 121 may be within 0.01 mm of each other.In another example, the first mold surface 140 and the first die surface 121 can be within 0.001 mm of each other. The molding compound can comprise any type of molding compound, including but not limited to a remote bonding agent, a thermosetting resin, an epoxy, or an adhesive, and can be formulated to have a specific CTE value or a range of CTE values.

[0025] In some embodiments, the molding compound 132 contacts or bonds with a lateral surface 144 of the stiffening element 124 (for example, the body of the molding compound 132 contacts the stiffening element 124, the die 116, and the substrate 104 in a continuous manner). For example, in the case of a stiffening element 124 configured or shaped as a ring surrounding the die, the molding compound 132 can be applied such that it covers a portion of the substrate 104, has a first molded surface 140 that is substantially flush with the first die surface 121, and / or contacts the inner lateral surface 144 of the stiffening element, as shown in Fig. Figure 1B shows a top view of the package 100 with the die 116, the stiffening element 124 (for example, configured as a ring) and the substrate. Fig. Figure 1C illustrates this. The molding compound 132 reduces stresses along the substrate 104. For example, the molding compound 132 reduces the tensile stress on the substrate 104 at or near the stiffening element 124 by distributing a tensile stress that exists along the interface between the inner lateral surface 144 of the stiffening element 124 and the interface between the molding compound 132 and along the first surface 118 of the substrate 104, thus preventing cracks in the substrate 104 that may develop near the stiffening adhesive 128. It should be noted that in some cases the molding compound 132 does not come into contact with the stiffening element 124. Therefore, the above description should not be considered a limitation of the present disclosure, but rather an illustration.

[0026] In some embodiments, the system 90 comprises a heat sink 148 configured to be connected to the first die surface 121 and the first mold surface 140, as shown in Fig. Figure 1D shows that the heat sink 148 also transfers heat away from the die 116 and the substrate 104, as shown in Figure 1. Fig. Figure 1D shows the heat sink 148 as a heat sink of any type, including but not limited to actively cooling heat sinks, passively cooling heat sinks, vapor chamber and heat tube heat sinks, fan-cooled heat sinks, thermoelectric heat sinks, and the like. For example, the heat sink 148 can be configured as a passive heat sink 148 having a heat sink base 152 connected to the first die surface 121 and the first mold surface 140 at a heat sink coupling surface 156 (for example, a first surface of the heat sink 148). The heat sink can also include one or more heat transfer elements 160. The heat transfer elements 160 can be of any type, size, shape, or number.

[0027] In embodiments, at least one dimension (for example, X or Y) of the heat sink coupling surface 156 is longer than at least one dimension of the first die surface 121, the heat sink coupling surface overlapping the first die surface 140. The overlap of the heat sink coupling surface 156 over the first die surface 121 maximizes heat dissipation from the die 116 through the heat sink 148. Because the first die surface 140 is flush or coplanar with the first die surface 121, it is prevented that the corners and edges of the die 116 contact the heat sink surface 156 at an angle that could lead to chipping and cracking at the corners and edges of the die.

[0028] Fig. Figure 2A shows a top view of the package 100 configured with a cross-shaped stiffening element 124, in accordance with one or more embodiments of the disclosure. In embodiments, the package 100 can comprise a plurality of dies 116a-j, wherein the molding compound 132 covers the entire area or substantially the entire area (for example, more than 90%) of the first surface 118 of the substrate 104 that is not coupled to package components (for example, all exposed surfaces of the substrate 104 that are not coupled to package components such as the stiffening element 124 and the plurality of dies 116a-j). In other words, the molding compound, the stiffening element, and the majority of the dies cover the entire or substantially the entire (for example, more than 90%) first surface 118 of the substrate 104. The lateral sides of each die 116 of the majority of dies 116a-j may be bounded by the molding compound 132. Fig. Figure 2B shows a cutaway side view of the package from Fig. 2A. As shown, the first mold surface 140 is essentially flush with the first die surfaces 121a-d.

[0029] The molding compound 132 can cover the entire first surface 118 of the substrate 104, as shown in Fig. 2A shown (first surface 118 not shown). The molding compound 132 can also partially cover the first surface 118 of the first substrate 104, with part of the first surface 118, for example at a perimeter 204 of the first surface 118, remaining uncovered or exposed, as in Fig. 2C is shown. For example, the package 100 may not require the molding compound 132 in parts of the package, such as at the edge where the substrate is under little stress. The perimeter 204 may comprise an area of ​​less than 10 percent, less than five percent, or less than one percent of the total area of ​​the first surface 118 of the substrate 104.

[0030] Fig. Figure 3A is a flowchart showing a method 300 for manufacturing the package 100 in accordance with one or more embodiments of the disclosure. The package 100 may comprise any type or size as described herein and any shape, size, or number of dies 116 and stiffening elements 124.

[0031] In embodiments, the method 300 comprises a step 302 of providing a die with a first die surface 121 (for example, an upper surface or first surface) and a second die surface 122 (for example, the lower surface or second surface). The die 116 can, for example, be configured as a flip-chip die that can be connected to the substrate 104 via controlled collapsing chip interconnects (for example, micro-solder bumps) arranged on the second die surface 122.

[0032] In embodiments, the method 300 comprises a step 304 of connecting a second die surface 122 (for example, the bottom) of the die 116 to the first surface 118 of the substrate 104. The die 116 can be any type of semiconductor chip containing an integrated circuit and can have any type of physical connection. For example, the die 116 can be configured as a flip-chip die with microbump connections that are connected to a corresponding arrangement of pads on the substrate 104.

[0033] In embodiments, the method 300 further comprises a step 308 of connecting the first surface 125 of a stiffening element 124 with the first surface 118 of the substrate 104. For example, the stiffening element 124 can be connected to the substrate 104 via the stiffening fastening adhesive 128, which contains an adhesive material.

[0034] In embodiments, the method 300 further comprises a step 312 of applying molding compound 132 to the first surface 118 of the substrate 104, at least one lateral surface 144 of the stiffening element 124, and at least one lateral die surface 136, wherein the first molding surface of the molding compound 132 is substantially flush with the first surface of the die 116. The molding compound 132 provides protection for the die by preventing cracking during the coupling of a heat sink 148 with the die 116, and also reduces local stresses on the substrate 104, such as stresses at the stiffening interface 128 due to the CTE value of the molding compound 132, as explained in more detail below. Method 300 can further comprise a step of attaching (coupling) a heat sink 148 to the first die surface 121 and the first mold surface 140, as shown in Fig. Shown in 1D.

[0035] Fig. Figure 3B is a flowchart illustrating a method 350 for manufacturing the package 100, in which the molding compound 132 does not contact the stiffening element 124, in accordance with one or more embodiments of the disclosure. The package 100 manufactured by this method 350 incorporates the protective aspects of the molding compound 132 but does not provide stress reduction at the stiffening interface 128. Similar to method 300, method 350 includes a step 352 of providing a die 116 with a first die surface 121 and a second die surface 122 facing the first die surface 121. Method 350 further includes a step 354 of joining the second die surface 122 to the first surface 118 of the substrate 104.Method 350 further comprises a step 358 of applying molding compound to the first surface 118 of the substrate 104 and to at least one lateral surface of the die 116, wherein the first molding surface 140 of the molding compound 132 is substantially flush with the first surface of the die 116. Method 350 further comprises a step 362 of joining the first surface 125 of the stiffening element 124 to the first surface 118 of the substrate 104.

[0036] In some embodiments, the stiffening element 124 is partially or completely covered by the molding compound 132, as in Fig. 4A-B shown, in accordance with one or more embodiments of the disclosure. For example, the height of the stiffening element 124 may be less than the height of the die 116, so that when the molding compound 132 is arranged on the substrate 104, the first mold surface 140 is substantially flush or coplanar with the first die surface 121. The molding compound 132 may also partially or completely cover an upper surface 404 of the stiffening element. As shown, for example, in Fig. Figure 4A shows a cutaway side view of the package 100 with a stiffening element 124 configured as a ring covering the boundary / edge of the first surface 118 of the substrate. The molding compound 132 covers more than half of the upper stiffening surface 404. In another example in Fig. Figure 4B, which shows a cutaway side view of a package 100 with a stiffening element 124 configured as a rod along a center of the package 100, the molding compound 132 covers the entire upper surface of the stiffening.

[0037] Fig. Figures 5A-C show a cutaway side view of a CoWoS (chip-on-wafer-on-substrate) package 200 containing a CoW (chip-on-wafer) 504 according to one or more embodiments of the disclosure. The CoWoS package 200 can contain one, more, or all of the components of the package 100, and vice versa. For example, the CoW 504 can contain an interposer 512 connected to the first surface 118 of the substrate 104, with the die 116, a memory stack 508, or other semiconductor components connected to the interposer 512. The CoW 504 can be assembled at a different manufacturing site before being placed on the substrate 104 to complete the assembly of the CoWoS package. The components on the top side of the interposer 512 are often encapsulated with a potting compound or encapsulation molding compound (EMC) 516, which protects the components and their interconnections with the interposer 512.stabilized.

[0038] In embodiments, one of the dies 116 of the CoW 504 comprises a die 116 with a first die surface 121 that is nearly or substantially flush with the first surface 140 of the molding compound 132. For example, the molding compound 132 can be introduced into the package 100 such that the first surface 140 is substantially flush with the first die surface 121 of the tallest die 116 in the CoW 504 or the CoWoS package 200. The stiffening element 124 can be higher than the first surface 140 of the molding compound 132. For example, the upper stiffening surface 404 can be higher than the first surface 140 of the molding compound 132, and the molding compound 132 can be applied such that no molding compound 132 covers the upper stiffening surface, as shown in Fig. 5A shown. In another example, the stiffening element 124 is shorter than the first die surface 121, and the molding compound 132 is applied such that the molding compound 132 partially or completely covers the upper stiffening surface 404, as shown in Fig. 5B is shown. In another example, the molding compound 132 does not touch the stiffening element 124, as shown in Fig. 5C is shown.

[0039] In some embodiments, the die 116 is configured as a chiplet module containing multiple chiplets. Chiplets are smaller than conventional dies, with several chiplets fitting into a conventional package 100. The package 100 can contain multiple chiplet modules and may include one or more dies 116 within a larger chiplet module.

[0040] Fig. Figures 6A-C are drawings showing a cutaway side view of the package 100 with an annular stiffening element 124 and several dies 116a-c according to one or more embodiments of the disclosure. In embodiments, the dies 116a-c have a similar height, and the molding compound 132 is applied to the package 100 such that the first mold surface 140 is substantially flush or coplanar with the first die surfaces 121a-c or two, more, or all of the dies 116a-c. In cases where the dies 116a-c are of different heights, the molding compound 132 can be applied to the package 100 such that one of the first die surfaces 121a-c (for example, the tallest die 116a-c) is substantially flush with the first mold surface 140. Fig. 6B, for example, has the first form surface 140, which is coplanar with the first die surface 121 of the tallest chip 116b. In some cases, the first form surface 140 is flush with the first die surface of a die 116 that is not the tallest chip or the tallest package component on the substrate 104. In another example, the package 100 can contain multiple first form surfaces 140 based on different areas of the package 100. For example, the package 100 can have multiple form surfaces 140 for the dies 116 with different heights.

[0041] Fig. Figures 6A-C also show different configurations of the stiffening element 124 and the molding compound 132. For example, the molding compound 132 can be applied such that it covers part of the lateral surface 144 of the stiffening element 124, as shown in Fig. 6A shown, or covering part or all of the upper stiffening surface 404, as shown in Fig. 6B shown. The molding compound 132 does not touch the stiffening element 124, as shown in Fig. 6C is shown.

[0042] In some embodiments, the molding compound 132 is formulated such that it has a CTE value, CTE Mold , which serves to reduce local stresses at the interface between package components, such as the stiffening adhesive 128, or at the interface between the die 116 and the substrate 104. For example, the molding compound can be formulated to have a CTE Mold -value that lies between the values ​​of the WAK Versteifungselement -value and the WAK Die -value lies (for example, CAC) Die < WAK Mold < WAK Versteifungselement For example, the molding compound 132 can be formulated in such a way that it has a CTE (coefficient of thermal expansion). Mold -value of approximately 7 ppm / °C, a value that lies between the values ​​of WAK Die (for example, approximately 3 ppm / °C) and the values ​​of CEC Versteifungselement(for example, typically 10-16 ppm / °C). In another example, Package 100 can be a molding compound 132 with a CTE. Mold -value of approximately 10 ppm / °C, a Die 116 with a CTE Die -value of approximately 3 ppm / °C and a stiffening element with a CTE Versteifungselement -value of approximately 15 ppm / °C.

[0043] Fig. Drawings 7A-B show a cutaway side view of the package 100 with an annular stiffening element 124 and a die 116 together with molding compound 132, which is subdivided into molded parts 704a-b, according to one or more embodiments of the disclosure. In embodiments, the molded parts 704a-b (for example, the parts of the molding compound) have different CTE values. For example, the first molded part 704a can have a first molded part CTE value, CTE 100. Mold1 , and the second molded part 704b a second molded part CTE value, CTE Mold2, exhibit. Molded parts 704a-b with different CTE values ​​can then be applied to the package 100, so that package components with significantly different CTE values ​​(for example, the die 116 and the stiffening element 124) come into contact with molded parts 704 with similar CTE values. For example, and with reference to Fig. 7A the package 100 can be a stiffening element 124 with a CTE value of 15 ppm / °C in contact with a first molded part 704a with a CTE Mold1 A value of 10 ppm / °C and a second molded part 704b with a CTE Mold2 Contains a value of 7 ppm / °C, which in contact with a die 116 with a CTE Die -value of 3 ppm / °C (for example, WAK) Die < WAK Mold2 < WAK Mold1 < WAK VersteifungselementBy arranging materials with different CTE values ​​on the substrate 104, a stepwise gradient of CTE values ​​is created. This gradient of CTE values ​​reduces local stresses at the stiffening interface 128, resulting in less distortion.

[0044] The molded parts 704a-b can be added in any order. For example, molded part 704a can first be attached to the first surface 118 of the substrate 104 and the side die surface 136 of the die 116. The stiffening element 124 can then be connected to the first surface 118 of the substrate 104. Finally, molded part 704b can be added, filling a gap between the stiffening element 124 and molded part 704a. Other combinations of steps for adding molded parts 704a-b to the package 100 are possible.

[0045] The molded parts 704 can also be arranged vertically, as shown in Fig.Figure 7B shows, in accordance with one or more embodiments of the disclosure (for example, the third molded part 704c is arranged on the first surface 118 of the substrate 104, and the fourth molded part 704d is arranged on the third molded part 704c). For example, the package 100 can include a third molded part 704c with a CTE value, CTE Mold3 , contained, which is relatively close (for example, 80%-100%) or greater than CTE Substrat is the component that is first applied to or arranged on the first surface 118 of the substrate. The package can also include a fourth component 704d with a CTE value, CTE Mold4 , which is smaller than WAK Mold3 (for example WAK) Mold3 < WAK Mold4 ), which is located on top of the third molded part 704c. For example, the package 100 can contain a substrate 104 with a CTE. Substrat -value of 12 ppm / °C, a third molded part 704c with a CTE Mold3of 10 ppm / °C and a fourth molded part 704d with a CTE Mold4 exhibiting a permeability of 7 ppm / °C. The vertically stacked arrangement of the molded parts 704 serves to reduce local stresses in the substrate, for example at the stiffening interface 128. The molded parts 704 can also be applied in arrangements other than vertical or horizontal layering. For example, the molded parts can be arranged diagonally or in application-specific configurations for the system 90.

[0046] The package can contain any number of molded parts 704, each having different CTE values, including, but not limited to, two molded parts 704, three molded parts 704, four molded parts 704, five molded parts 704, or more than five molded parts 704. In some embodiments, the molding compound is formulated to have a gradient of CTE values ​​from one end of the first mold surface 140 to the other. This gradient of CTE values ​​can result in a molding compound 132 having a virtually unlimited number of molded parts 704 with corresponding CTE values. The CTE value of a molding compound 132 containing multiple molded parts 704 can be determined according to the following equation: WAK=∑(mi / m)(ρ / ρi)WAKi, where m and ρ are the mass and density of the total molding compound 132 and m, respectively. i and ρ i the respective mass and density components of the molded parts 704 are.

[0047] The molding compound 132 and the molded parts 704 can be formulated to have any CTE value within any range of CTE values. For example, the molding compound 132 and the molded parts 704 can have CTE values ​​in the range of 2 to 20 ppm / °C, 3 to 18 ppm / °C, 4 to 16 ppm / °C, or 5 to 14 ppm / °C. The molding compound can, for example, have any CTE value, including but not limited to approximately 3 ppm / °C, approximately 4 ppm / °C, approximately 5 ppm / °C, approximately 6 ppm / °C, approximately 7 ppm / °C, approximately 8 ppm / °C, approximately 9 ppm / °C, approximately 10 ppm / °C, approximately 11 ppm / °C, approximately 12 ppm / °C, approximately 13 ppm / °C, approximately 14 ppm / °C, approximately 15 ppm / °C, approximately 16 ppm / °C or approximately 15 ppm / °C.

[0048] It is understood that the arrangement of the molding compound 132 on the substrate 104, the die 116, or the stiffening element 124 may include one or more intermediate layers between the molding compound 132 and the substrate, the die 116, or the stiffening element 124. For example, the substrate 104, the die 116, and / or the stiffening element 124 may contain one or more coatings (for example, waterproof coatings, laminations, or conformal coatings such as acrylic resin, silicone resin, or urethane resin) that were applied prior to the application of the molding compound 132. Therefore, the above description should not be considered a limitation of the present disclosure, but rather an illustration.

[0049] It is understood that embodiments of the methods disclosed herein may include one or more of the steps described herein. Furthermore, these steps may be performed in any order, and two or more of the steps may be performed simultaneously. Two or more of the steps disclosed herein may be combined into a single step, and in some embodiments, one or more of the steps may be performed as two or more sub-steps. In addition, other steps or sub-steps may be performed in addition to or as a replacement for one or more of the steps disclosed herein.

[0050] Although the concepts according to the invention have been described with reference to the embodiments illustrated in the accompanying drawings, equivalents may be used and substitutions made without departing from the scope of the claims. The components shown and described here are merely examples of a system / device and components that can be used to implement embodiments of the concepts according to the invention and can be replaced by other devices and components without departing from the scope of the claims. Furthermore, all dimensions, degrees, and / or numerical ranges given here are to be understood as non-limiting examples unless otherwise specified in the claims.

Claims

[1] System (90) which includes the following: a package (100) that includes the following: a substrate (104) with a first surface (118); a die (116) with a first surface (121), a second surface (122) and a side surface, wherein the first surface (121) and the second surface (122) are opposite each other and the second surface of the die is connected to the first surface (118) of the substrate (104); a stiffening element (124) with a first surface (125), wherein the first surface (125) of the stiffening element (124) is connected to the first surface (118) of the substrate (104) via a first interface; and Molding compound (132) with a first molding surface (140) arranged in a continuous mold on the first surface (118) of the substrate (104) and on the side surface (136) of the die (116), wherein a coefficient of thermal expansion (CTE) value of the molding compound (132) is greater than a CTE value of the die (116); wherein the first mold surface (140) of the molding compound (132) is coplanar with the first surface (121) of the die (116); further comprising a heat sink (148) which is connected to the first surface (121) of the die (116) and the first mold surface (140). [2] System (90) according to claim 1, wherein the molding compound (132) is further arranged on a lateral surface (144) of the stiffening element (124). [3] System (90) according to one of claims 1 to 2, wherein the stiffening element (124) further comprises an upper stiffening surface (404), wherein the first mold surface (140) covers at least a part of the upper stiffening surface (404). [4] System (90) according to claim 3, wherein the first mold surface (140) covers the entire upper stiffening surface (404). [5] System (90) according to any one of claims 1 to 4, wherein the molding compound (132) comprises a plurality of molded parts (704a, 704b, 704c, 704d), wherein the plurality of molded parts (704a, 704b, 704c, 704d) comprises a first molded part (704a) with a first molded part CTE value and a second molded part (704b) with a second molded part CTE value, wherein the first molded part CTE value is greater than the second molded part CTE value. [6] System (90) according to claim 5, wherein the first molded part (704a) is in contact with the lateral surface (144) of the stiffening element (124), wherein the second molded part (704b) is in contact with a lateral surface (136) of the die (116). [7] System (90) according to claim 5 or 6, wherein the first molded part is formed on the first surface of the substrate (104), wherein the second molded part (704b) is formed on the first molded part (704a). [8] System (90) according to any one of claims 1 to 7, wherein the stiffening element (124) is shaped as a ring. [9] System (90) according to any one of claims 1 to 7, wherein the stiffening element (124) is shaped as a cross and / or a beam. [10] System (90) according to any one of claims 1 to 9, wherein the die (116) is configured as a chip-on-wafer-on-substrate (CoWoS). [11] System (90) according to any one of claims 1 to 10, wherein the system includes a printed circuit board (108) which is connected to the substrate (104) in an operational state. [12] System (90) according to claim 2, wherein the CTE value of the molding compound (132) is less than a CTE value of the stiffening element (124). [13] System (90) according to any one of claims 1 to 12, further comprising a plurality of dies (116), wherein the molding compound (132), the stiffening element (124) and the plurality of dies (116) cover more than 90% of the first surface (118) of the substrate (104). [14] System (90) according to any one of claims 1 to 13, wherein a circumference of the substrate (104) is not covered by the molding compound (132). [15] System (90) according to any one of claims 1 to 14, wherein the substrate (104) has a dimension of 45 mm or more. [16] System (90) according to any one of claims 1 to 15, wherein the substrate (104) has a dimension of 65 mm or more. [17] Method comprising the following: Providing a die (116) with a first surface (121) and a second surface (122) opposite the first surface (121); Connecting the second surface (122) of the die (116) to a first surface (118) of a substrate (104); Connecting a first surface (125) of a stiffening element (124) to the first surface (118) of the substrate (104); and Arranging molding compound (132) on: the first surface (121) of the substrate (104); at least one lateral side of the stiffening element (124); and at least one lateral surface (136) of the die (116), wherein a first mold surface (140) of the molding compound (132) is coplanar with the first surface (121) of the die (116); the method further comprises attaching a heat sink (148) to the first surface (121) of the die (116) and the first mold surface (140).

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