Semiconductor assemblies and systems and methods for managing high die stack structures

Abstract

This application relates to semiconductor assemblies and systems and methods for managing high die stack structures. The semiconductor device includes a rigid-flexible circuit having a first rigid region and a second rigid region electrically connected by a flexible portion. A first die is mounted to a first side of the first rigid region. A second die is mounted to a second side of the second rigid region. The first and second sides are located on opposite sides of the rigid-flexible circuit. The flexible portion is bent to hold the first and second rigid regions substantially vertically aligned with each other.

Description

Technical Field

[0001] This invention relates to semiconductor device packaging. More specifically, some embodiments of this invention relate to structures and techniques for attaching high die stack structures to a substrate. Background Technology

[0002] For example, packaged semiconductor dies for memory chips, microprocessor chips, and imaging chips typically comprise semiconductor dies mounted on a substrate and encased in a protective covering. Semiconductor dies may contain functional features such as memory cells, processor circuitry, and imaging devices.

[0003] Market pressures are constantly driving semiconductor manufacturers to reduce the size of die packages to fit the space constraints of electronic devices, while simultaneously increasing the functional capacity of each package to meet operating parameters. One method to increase the processing power of a semiconductor package without substantially increasing the surface area covered by the package (i.e., the package's "coverage area") is to vertically stack multiple semiconductor dies on top of each other within a single package. Dies in such vertically stacked packages can be electrically coupled to each other and / or electrically coupled to the substrate via electrical connectors, interconnects, or other conductive structures. However, as the number of electrical connectors connecting the stacked dies to the substrate increases, the area required for attaching the connectors also increases, thus reducing the space available for other components and connections. Furthermore, keeping the connectors separate from each other can become increasingly difficult. Summary of the Invention

[0004] In one aspect, this disclosure relates to a semiconductor device comprising: a rigid-flexible circuit having a first rigid region and a second rigid region electrically connected by a flexible portion; a first die mounted to a first side of the first rigid region; and a second die mounted to a second side of the second rigid region, the first side and the second side being located on opposite sides of the rigid-flexible circuit, wherein the flexible portion is bent to hold the first rigid region and the second rigid region substantially vertically aligned with each other.

[0005] In another aspect, this disclosure relates to a semiconductor device comprising: a rigid-flexible circuit having a first rigid region and a second rigid region electrically connected by a flexible portion, each of the first rigid region and the second rigid region having at least one bonding pad thereon, wherein the flexible portion is configured to bend approximately 180 degrees to hold the first rigid region and the second rigid region substantially vertically aligned with each other; a first die mounted to a first side of the first rigid region, the first die being electrically connected to the at least one bonding pad on the first rigid region; a second die mounted to a second side of the second rigid region, the second die being electrically connected to the at least one bonding pad on the second rigid region, wherein the first side of the first rigid region and the second side of the second rigid region are located on opposite sides of the rigid-flexible circuit; a packaging substrate connected to the rigid-flexible circuit when the rigid-flexible circuit is bent to substantially vertically align the first die and the second die; and an electrical connector connecting the rigid-flexible circuit and the substrate.

[0006] In another aspect, this disclosure relates to a method for forming a semiconductor device, comprising: mounting a first die to a first side of a first rigid region of a rigid-flexible circuit; mounting a second die to a second side of a second rigid region of the rigid-flexible circuit opposite to the first side of the first rigid region; and bending a flexible portion by about 180 degrees to align the first rigid region and the second rigid region substantially vertically with each other, the flexible portion extending between the first rigid region and the second rigid region and electrically connecting the first rigid region and the second rigid region. Attached Figure Description

[0007] The following figures provide a better understanding of many aspects of the invention. The components in the figures are not necessarily drawn to scale. The focus is on illustrating the principles of the invention.

[0008] Figure 1A A cross-sectional view of a stack of multiple bare dies attached to a rigid-flexible circuit according to an embodiment of the present invention.

[0009] Figure 1B The embodiments of the present invention are described below. Figure 1A Top and bottom views of the rigid-flexible circuit components.

[0010] Figure 1C According to embodiments of the present invention, the blanks have been bent to vertically align the stacked blanks in a vertically aligned assembly. Figure 1A A cross-sectional view of the bare die stack assembly.

[0011] Figure 1D This illustrates an embodiment of the invention, encapsulated in molding material. Figure 1C A cross-sectional view of the bare die stack assembly.

[0012] Figure 2 This is a cross-sectional view of a rigid-flexible circuit according to an embodiment of the present invention.

[0013] Figure 3 This is another cross-sectional view of an assembly comprising a plurality of die stacks and a rigid-flexible circuit in vertical alignment, according to an embodiment of the present invention.

[0014] Figure 4A A cross-sectional view of a die stack and a controller die mounted on a rigid-flexible circuit according to an embodiment of the present invention.

[0015] Figure 4B According to an embodiment of the invention, the die has been bent to position the die stack above the controller die. Figure 4A A cross-sectional view of the assembly.

[0016] Figure 4C For embodiments of the present invention, already mounted on a substrate Figure 4B A cross-sectional view of the vertically aligned assembly.

[0017] Figure 4D For embodiments of the present invention, the installation on the opposite side of the rigid-flexible circuit is related to... Figure 4A The cross-sectional view of a component similar to the one used in the example.

[0018] Figure 5A A cross-sectional view illustrating the use of rigid-flexible circuitry in a side-by-side or adjacent die stack structure according to an embodiment of the present invention.

[0019] Figure 5B For embodiments of the present invention, the bent and attached substrate and another die stack Figure 5A A cross-sectional view of the bare die stack assembly.

[0020] Figure 5C The embodiments of the present invention are described below. Figure 5A Top and bottom views of the rigid-flexible circuit components.

[0021] Figures 6A to 6C A top-down view illustrating a process for manufacturing a stacked assembly of multiple bare dies according to an embodiment of the present invention.

[0022] Figure 7 A flowchart illustrating a method for manufacturing a semiconductor device assembly according to an embodiment of the present invention.

[0023] Figure 8A schematic diagram illustrating a system comprising a semiconductor device assembly configured according to an embodiment of the present invention. Detailed Implementation

[0024] The following describes specific details of several embodiments of a semiconductor device. In some embodiments, multiple die stacks may be mounted (e.g., attached) to a rigid region of a rigid-flexible circuit. As described herein, a die stack may contain a single die or more than one die. The rigid-flexible circuit may be a laminated structure containing one or more inner layers capable of transmitting signals. Electrical connectors (e.g., bonding wires, solder interconnects, etc.) may connect some of the dies within the die stack to each other and to wires on the rigid-flexible circuit that communicate with appropriate signal transmission layers. The rigid region of the rigid-flexible circuit may alternate with flexible portions that allow the rigid-flexible circuit to bend, for example by bending the flexible portions approximately 180 degrees, so that at least some of the attached die stacks are substantially vertically aligned with each other. In some cases, spacers (e.g., attached to the die stack and / or the rigid-flexible circuit) may be used to separate the top side of the die stack or other components from the rigid-flexible circuit when the assembly is substantially or substantially vertically aligned. One of the rigid regions of any of the die stacks or the vertically aligned assembly may be attached to a substrate. Electrical connectors can connect rigid and flexible circuits and substrates to transmit signals associated with multiple die stacks to and / or from the substrate.

[0025] Using rigid-flex circuitry to form vertically aligned assemblies of die stacks allows for the use of shorter leads, which can contribute to cost-effectiveness. Shorter leads also reduce common wire sweep and / or short-circuit issues that can occur during the assembly process. Additionally, fewer individual electrical connectors are required to connect to the substrate. Therefore, less space is needed for electrical connections on the substrate, and more components can be included within the same coverage area. Additional benefits can be achieved by applying impedance control to differential / high-speed signals on the rigid-flex circuitry to improve signal integrity by reducing wire-to-wire crosstalk and interference.

[0026] In some cases, such as but not limited to, other components of the controller die, other than those of the controller die, may be mounted to the rigid region of the rigid-flexible circuit. The controller die may be molded or pre-molded after attachment. A vertically aligned assembly can be formed by bending one or more flexible portions to position the die stack attached to the rigid-flexible circuit above the controller die. In other embodiments, the rigid-flexible circuits may be used in a side-by-side configuration, wherein one or more die stacks attached to the rigid-flexible circuit may be positioned above a die stack or other components mounted on a substrate close to the rigid-flexible circuit. This can provide increased capacity within the same coverage area by utilizing the open space above the mounted components and / or increasing capacity while keeping the total height of the die stack and / or vertically aligned assembly within the desired limits and / or ranges.

[0027] In some embodiments, the die stack may be formed on the rigid-flexible circuit, while in other embodiments, the die stack may be pre-formed and subsequently mounted on the rigid-flexible circuit. Electrical connections between the dies, the die stack, and the rigid-flexible circuit may be implemented before bending the rigid-flexible circuit or, for example, iteratively between multiple bending operations. Some of the die stacks and / or components may be attached to a first side of the rigid-flexible circuit, and subsequently other die stacks and / or components may be attached to a second side of the rigid-flexible circuit. In this example, a clamp may be used to “flip” one or more rigid-flexible circuits from one side to the other.

[0028] Those skilled in the art will recognize that, unless the context otherwise indicates, conventional semiconductor manufacturing techniques can be used to form the structures disclosed herein. Materials can be deposited, for example, using chemical vapor deposition, physical vapor deposition, atomic layer deposition, plating, electroless plating, spin coating, and / or other suitable techniques. Similarly, materials can be removed, for example, using plasma etching, wet etching, chemical mechanical planarization, or other suitable techniques.

[0029] Numerous specific details are disclosed herein to provide a thorough and useful description of embodiments of the invention. However, those skilled in the art will understand that the technology may have additional embodiments, and that the technology may be described without further reference. Figures 1A to 6C The described embodiments are practiced in several details. For example, some details of semiconductor devices and / or packages well known in the art have been omitted to avoid obscuring the technical aspects of the invention. Generally, it should be understood that various other devices and systems besides the specific embodiments disclosed herein are within the scope of the invention.

[0030] As used herein, the terms “vertical,” “horizontal,” “upper,” “lower,” “above,” and “below” may refer to the relative orientation or position of a feature in a semiconductor device, given the orientation shown in the figures. For example, “upper” or “topmost” may refer to a feature positioned closer to the top of the page than another feature. However, these terms should be broadly understood to include semiconductor devices with other orientations, such as inverted or tilted orientations, where top / bottom, above / below, above / below, up / down, and left / right may be interchanged depending on the orientation.

[0031] Figures 1A to 1D This illustration shows a view of a semiconductor die attached to a rigid-flexible circuit according to an embodiment of the present invention. Specifically, Figure 1A This illustrates a side cross-sectional view of a stack of four bare dies attached to a rigid-flexible circuit (e.g., a rigid-flexible printed circuit board). Figure 1BShowing top and bottom views of a rigid-flexible circuit with attached components.

[0032] Figure 1C This illustration depicts a side cross-sectional view of a stack of bare wafers forming a vertically aligned assembly after the rigid-flexible circuit has been bent, according to an embodiment of the present invention. Figure 1D Showing individual dies attached to each rigid region of a rigid-flexible circuit.

[0033] refer to Figure 1A The rigid-flexible circuit 106a includes a plurality of rigid regions 120a to 120d alternating with one or more flexible portions 122a to 122c. Flexible portions 122 are electrically connected to adjacent rigid regions 120. The semiconductor device 100a is bendable to form a die stack assembly including a first die stack 102a and a third die stack 102c mounted or connected to a first side 104a of the rigid-flexible circuit 106a. A second die stack 102b and a fourth die stack 102d are mounted or connected to a second side 108a of the rigid-flexible circuit 106a. Die stacks 102 are mounted to rigid regions 120 of the rigid-flexible circuit 106a. Thus, as shown, adjacent die stacks 102 are attached to alternating or opposite sides of the rigid-flexible circuit 106a. Although four die stacks 102 are shown, it should be understood that more or fewer die stacks 102 may be attached to the rigid-flexible circuit 106a, such as two die stacks 102, three die stacks 102, or more than four die stacks 102.

[0034] In some embodiments, a die stack 102 can be formed on the rigid flexible circuit 106a by attaching a first die 110 to a rigid region 120 of the rigid flexible circuit 106a, attaching a second die 110 over at least a portion of the exposed side of the first die 110, etc. Die attachment films or other known materials and methods can be used. The first die stack 102a comprises individual semiconductor dies 110a to 110h vertically stacked in a shingled or stepped configuration, wherein each die 110 is horizontally offset from the adjacent die 110. For example, Figure 1AA die stack 102 is depicted in a configuration that may be referred to as "anti-shingled on shingled," wherein dies 110a to 110d are stepped in a first horizontal direction (e.g., first shingled), and dies 110e to 110h are stepped in a second horizontal direction opposite to the first horizontal direction (e.g., second shingled). It should be understood that the die stack 102 can be formed by aligning individual dies 110 such that none or some of the dies 110 are shingled relative to other dies 110 within the same die stack 102. The dies 110 may be memory dies, such as NAND dies, SRAM dies, or other semiconductor dies. Furthermore, although eight dies 110 are depicted in each of the die stacks 102, more or fewer dies 110 may be included based on system requirements. For example, as described below... Figure 1D As discussed herein, a single die 110 may be attached to each of the rigid regions 120. In some cases, not every rigid region may have a die 110 attached thereto.

[0035] A shingled or stepped configuration allows for electrical interconnection between adjacent dies 110 in the die stack 102, which shortens the electrical connector length and minimizes the number of electrical connections to the rigid-flexible circuit 106a or the substrate (both discussed further below). Therefore, two or more dies 110 in the die stack 102 can be electrically connected to each other via one or fewer electrical connectors and subsequently electrically connected to the rigid-flexible circuit 106a, thereby eliminating some bonding connections to the rigid-flexible circuit 106a (or the substrate). Bonding pads on the rigid-flexible circuit 106a ( Figure 2 (As shown in the figure) is connected to one or more communication layers within the rigid-flexible circuit 106a.

[0036] Multiple electrical connectors 112a to 112d (e.g., wire bonding) couple dies 110a to 110d to each other and to bonding pads (not shown for clarity) on the rigid-flexible circuit 106a to route signals (e.g., control signals, power signals, test signals, etc.) between these components. In some embodiments, the end of each electrical connector 112 is attached to a corresponding bonding pad (not shown for clarity) on the corresponding die 110. Thus, instead of requiring separate electrical connectors 112 to electrically connect each of the dies 110a to 110d to the rigid-flexible circuit 106a, a single electrical connector 112d transmits signals for all four dies 110a to 110d. The four dies 110e to 110h are similarly connected to electrical connectors 112f to 112i, with connector 112i extending from die 110e to the rigid-flexible circuit 106a. Die stacks 102b to 102d are similarly connected.

[0037] Each of the die stacks 102 has a top side 114 (e.g., an exposed side) and a bottom side 116. The surface of the die 110 attached to the rigid-flexible circuit 106a is the bottom side 116, and the surfaces of the dies 110 on opposite sides of the die stack 102 are the top sides 114. The top sides 114a to 114d and the bottom sides 116a to 116d of the die stacks 102a to 102d are indicated.

[0038] Inert spacers 118a to 118c may be attached to the rigid-flexible circuit 106a to provide mechanical and electrical separation between the rigid-flexible circuit 106a and the die stack 102 when the rigid-flexible circuit 106a is bent to position the die stack 102 in vertical alignment. Die attachment films and / or other known materials and methods may be used to attach the spacers. Spacers 118a and 118c are positioned on a second side 108a of the rigid-flexible circuit 106a, on a rigid region 120 opposite the first die stack 102a and the third die stack 102c, respectively. Spacer 118b is positioned on a first side 104a of the rigid-flexible circuit 106a, on a rigid region 120 opposite the second die stack 102b. In some embodiments, spacer 118 may be a “blank” substrate that does not contain semiconductor components and is formed of, for example, a substrate material (e.g., silicon, glass, ceramic, and / or other suitable materials).

[0039] Figure 1B exhibit Figure 1A Top view 130a and bottom view 132a of the semiconductor device 100a. Top view 130a and bottom view 132a correspond to the first side 104a and the second side 108a of the rigid-flexible circuit 106a, respectively. A rigid region 120 and a flexible portion 122 are indicated, as well as die stacks 102a to 102d and spacers 118a to 118c mounted or connected to the first side 104a and the second side 108a of the rigid region 120.

[0040] The rigid-flexible circuit 106a has length L1 and width W1 dimensions configured to accommodate the size and number of die stacks 102 and / or other components attached to the rigid region 120, and the length required to bend the flexible portion 122 when the die stacks 102 are vertically aligned. More die stacks 102 can be added to the same rigid-flexible circuit 106a by extending the alternating pattern of the rigid region 120 and the flexible portion 122. For example, as discussed below, an even number of die stacks 102 will be added to maintain the same scheme for folding and attaching the vertically aligned die stacks 102 to the substrate. In other instances, a non-even number of die stacks 102 may be added.

[0041] Each of the rigid regions 120 has a length L2 and a width W2 (indicated on rigid region 120d). The length L2 and width W2 of the other rigid regions 120a to 120c may be the same as or different from that of rigid region 120d. The spacers 118a to 118c shown have a smaller coverage area than the width W2 and length L2 of their corresponding rigid regions 120a to 120c. The die stacks 102a to 102d also have a smaller coverage area than at least the length L2 of their corresponding rigid regions 120, thus leaving edge regions 134 (indicated as edge regions 134a and 134b on rigid region 120a). Edge regions 134 include a plurality of bonding pads 136 (indicated as bonding pads 136a to 136h on edge region 134a) for electrically connecting the electrical connector 112 from the die 110. Figure 1A (As shown in the diagram). Although the die stack 102 and spacer 118 are geometrically shown within the length L2 and width W2 dimensions of the rigid region 120, the components may extend beyond one or more edges of the rigid region 120.

[0042] Each of the flexible portions 122 has a length L3, which is based on the height of the die stack 102 and / or spacers 118 and / or assemblies extending alongside the flexible portion 122 when the rigid flexible circuit 106 is bent. Furthermore, the length L3 of the flexible portion 122 can vary.

[0043] Return to Figure 1AOnce the die stack 102 and spacer 118 are attached to the rigid-flexible circuit 106a and the electrical connector 112 is attached as needed, the rigid-flexible circuit 106a can be bent to substantially vertically align the die stack 102 to form a die stack assembly. For example, the flexible portion 122c of the rigid-flexible circuit 106a can be bent in the direction of arrow 124c to vertically align the die stack 102d with the die stack 102c. In other words, the flexible portion 122c can be bent approximately 180 degrees to keep the rigid regions 120c to 120d substantially vertically aligned with each other. The top side 114d (e.g., the exposed side) of the die stack 102d can be mechanically connected to (e.g., contacted and / or adhered to) the spacer 118c. The flexible portion 122b of the rigid-flexible circuit 106a can then be bent in the direction of arrow 124b to vertically align the die stacks 102c to 102d with the die stack 102b, thereby aligning with the rigid regions 120b to 120d. The top side 114c of the die stack 102c can be mechanically connected to the spacer 118b. The flexible portion 122a of the rigid-flexible circuit 106a can be bent in the direction of arrow 124a to vertically align the die stacks 102b to 102d with the die stack 102a, thereby also aligning with the rigid regions 120a to 120d. The top side 114b of the die stack 102b can be mechanically connected to the spacer 118a. It should be understood that the flexible portions 122a to 122c of the rigid-flexible circuit 106a can be bent in different sequences to align with the die stacks 102a to 102d.

[0044] Additionally, when the rigid regions 120 are generally kept vertically aligned with each other, space can be maintained between the top side 114 (e.g., the exposed side) of the die 110 or die stack 102 and the spacer 118 and / or rigid region 120. It should be understood that the embodiments discussed herein are not limited to all rigid regions 120 and die stacks 102 and / or dies 110 mounted thereon in a perfectly vertically aligned manner, and embodiments in which some offset may exist between these features are contemplated.

[0045] Vertically aligned die stacks 102a to 102d form a vertically aligned assembly 140a that can be attached to a substrate 142, such as Figure 1C As shown in the illustration. Substrate 142 may be a semiconductor substrate (e.g., a silicon substrate, a gallium arsenide substrate, an organic laminate substrate, etc.) or other suitable materials known in the art. In this example, as shown in... Figure 1B As seen in the top view 130a, the rigid region 120d is attached to the substrate 142, for example, by using a die attachment film or other known materials and methods. As seen in this side cross-sectional view, the length L2 of the rigid region 120 extends beyond the width of the die stack 102, and the length L3 of the flexible portion 122 extends approximately in relation to the height of the die stack 102 and the spacer 118.

[0046] After the vertically aligned assembly 140a is attached to the substrate 142, an electrical connection can be made between the rigid-flexible circuit 106a and the substrate 142. A wire bonding avoidance region 144 is displayed on the substrate 142 near the vertically aligned assembly 140a. An electrical connector 112e extends to the wire bonding connection point 146a, such as a ball grid array (BGA). After the electrical connection has been made between the vertically aligned assembly 140a and the substrate 142, an encapsulation or molding material 148 can then be formed around the die stack 102 of the vertically aligned assembly 140a and the electrical connector 112, such as... Figure 1D As shown, this provides structural integrity and environmental sealing. Multiple solder balls 150 may be formed on opposite sides 152 of the substrate 142. The solder balls 150 may connect to various conductive features (not shown) formed within the substrate 142, such as internal contacts, vias, and traces. For example, one or more of these conductive features may provide electrical connections (e.g., power, ground, and signal) to wire bonding connection points 146a.

[0047] Although the semiconductor device assembly has been described and depicted in the foregoing example embodiments as comprising a die stack 102 disposed over four rigid regions 120 of the rigid-flexible circuit 106, in other embodiments of the invention, a different number of dies (e.g., 1, 2, 3, 5, 6, 7, 8, etc.) may be disposed on each of any number of rigid regions 120 (e.g., 2, 3, 5, 6, 7, 8, etc.) of the rigid-flexible circuit 106.

[0048] When using rigid-flexible circuitry 106a to form a stacked die structure, such as a vertically aligned assembly 140a, technical advantages are achieved, for example, a smaller wire engagement avoidance area 144 and a shorter electrical connector 112. (See reference) Figure 1CIn the assembly 104a, a stack of bare dies 102a is formed, with electrical connectors 112f to 112h connecting dies 110e to 110h, and electrical connector 112i providing electrical connection for all dies 110e to 110h to the rigid-flexible circuit 106a. If the vertically aligned assembly 104a containing 32 dies 110 does not include the rigid-flexible circuit 106a, then the electrical connector 112i would instead extend from the dies 110e to the substrate 142. This results in long electrical connectors 112 that are difficult to attach to the substrate 142, and each electrical connector 112 requires space to attach without interference from other electrical connectors 112. Using the rigid-flexible circuit 106a minimizes the amount of space required to engage the electrical connectors 112 and increases the available space on the substrate 142 to allow for the mounting of additional passive and / or active components. In other words, when the rigid-flexible circuit 106a is used to form the vertically aligned assembly 140a, the required coverage area on the substrate 142 is reduced, while the capacity is increased.

[0049] For example, a stacked die structure using 16 dies 110 without rigid flexible circuitry 106a may have a wire engagement avoidance area 144 of approximately 600 micrometers (e.g., micrometers) and an electrical connector 112 extending approximately 1.5 millimeters (mm). A stacked die structure using 32 dies 110 without rigid flexible circuitry 106a may have a wire engagement avoidance area 144 of approximately 1200 micrometers and an electrical connector 112 extending approximately 3 mm. In some embodiments, for a vertically aligned assembly 140a with 32 dies 110, Figure 1C The wire bonding avoidance area 144 can be approximately 600 micrometers, or about the same size as a stacked die structure using 16 dies 110. Additionally, the length of the electrical connector 112 can be reduced to approximately 1 mm. It should be understood that these measurements are merely examples, and many factors, such as the thickness and number of dies 110, can vary the length of the electrical connector 112.

[0050] Figure 2 A side cross-sectional view illustrating a multi-layered rigid-flexible circuit 106a according to an embodiment of the present invention is shown. A rigid region 120 and a flexible portion 122 are shown. The rigid-flexible circuit 106a is a stack and / or lamination of layers. Depending on the required functionality, the rigid and flexible portions 120, 122 may contain different layers.

[0051] Figure 2 The rigid-flexible circuit 106a shown is merely exemplary. The number and configuration of layers can be determined based on the application. The size or number of layers can be increased to increase signal capacity. The layers and communication capacity of the rigid-flexible circuit 106a can be customized for the application, allowing different rigid-flexible circuits 106a to be used in different applications.

[0052] As shown, the rigid-flexible circuit 106a includes solder mask layers 200a to 200b, copper layers 202a to 202d, FR4 layers 204a to 204b, prepreg layers 206a to 206b, and a polyimide core layer 208. The solder mask layers 200a to 200b provide rigidity to the rigid region 120. Additional and / or different layers may extend beyond the rigid region 120 to form the flexible portion 122. For example, polyamide cover layers 210a to 210b, cover layer adhesive 212a to 212b, copper layers 202e to 202f, and the polyimide core layer 208. The polyimide core layer 208 provides the structure while allowing the flexible portion 122 to bend.

[0053] In some embodiments, an opening 214 within the outer layer of, for example, solder mask 200a may expose bonding pads 136i or other connection points for bonding wires to the rigid-flexible circuit 106a. Bonding pads 136i may be connected, for example, via vias (not shown) to one or more of the copper layers 202e to 202f. Vias may extend from the outer layer to the inner layer and may allow communication between two or more layers. Copper layers 202e to 202f, or other suitable layers, may be referred to as interconnect layers. In some cases, copper layers 202e to 202f may be patterned with copper traces (or other conductive materials) separated from each other to maintain signal separation where appropriate. In other cases, some or all of copper layers 202e to 202f may form a ground plane. Copper layers 202e to 202f (e.g., interconnect layers) may transmit signals between die stack 102 and / or other components mounted to the rigid-flexible circuit 106 and / or collection areas (not shown) of the rigid-flexible circuit 106a. One or more electrical connectors may be connected to the collection area to transmit signals to and / or from the substrate 142. This provides the advantage of a reduced area size of the substrate 142 required to provide interconnection with the die stack 102.

[0054] Figure 3 This describes another vertically aligned assembly 140b formed according to an embodiment of the present invention. (As opposed to...) Figure 1A As discussed, die stacks 102e to 102g and spacers 118d to 118f are attached to a rigid-flexible circuit 106b to form a semiconductor device 100b. Therefore, the rigid-flexible circuit 106b transmits signals between the die stacks 102e to 102g and the substrate 142. Figure 1C In contrast, the rigid-flexible circuit 106b is not located between the fourth die stack 102h and the substrate 142, thus reducing the overall height of the vertically aligned assembly 140b. This provides the advantage of allowing one or more additional dies 110 to be added to the vertically aligned assembly 140b, thereby increasing the overall capacity of the semiconductor package.

[0055] The die stack 102h can be attached to the substrate 142, for example, using a die attachment film. In some embodiments, die 110i can be attached to the substrate 142 and subsequent dies 110 can be attached to form a reverse shingle on the shingled configuration of the die stack 102h. In other embodiments, the die stack 102h can be formed separately and then attached to the substrate 142. Once the die stack 102h is attached to the substrate 142, electrical connectors 112 can be connected between dies 110i to 110l and dies 110m to 110p. Electrical connector 112j is connected to the substrate 142 at wire bonding connection point 146b and transmits signals between the four dies 110m to 110p connected together and the substrate 142. Electrical connector 112k is connected to the substrate 142 at wire bonding connection point 146c and transmits signals between the four dies 110i to 110l connected together and the substrate 142.

[0056] The rigid-flexible circuit 106b may be positioned above the die stack 102h, such that the spacer 118f communicates with the top side of the die stack 102h. In some cases, the spacer 118f may be adhered to the die stack 102h. The rigid-flexible circuit 106b may have a connection pad 302 that connects one or more electrical connectors of the rigid-flexible circuit 106b to the substrate 142 at a wire bonding connection point 146d. In some cases, a reflow operation may be used to reflow solder that may be present on one or both of the connection pads 302 and the wire bonding connection points 146d to attach the rigid-flexible circuit 106b to the substrate 142.

[0057] In other embodiments, one or more different components (e.g., active and / or passive components, shorter or taller die stacks, etc.) may be attached to substrate 142 instead of die stack 102h. The die stack assembly may then be positioned over one or more different components.

[0058] exist Figure 1C and 3 In the two embodiments shown, the technical advantages are achieved because less space is required on substrate 142 to interconnect the die stack 102 with substrate 142, thereby saving space for additional components. Furthermore, fewer electrical connectors 112 are required, which increases the ease of attaching the electrical connectors 112 to substrate 142 and reduces the problem of interference between the electrical connectors 112.

[0059] In some cases, it may be necessary to reduce the height of one or more die stacks 102 because A) the die stacks 102 are too tall for the package, B) to more evenly balance the height of adjacent die stacks 102, C) to minimize signal communication in the substrate 142 and / or D) to incorporate additional components. Figure 4AA die stack 102i and a controller die 400a are shown, respectively attached or connected to rigid regions 120e and 120f of a rigid-flexible circuit 106c, according to an embodiment of the present invention. The controller die 400a (e.g., a microcontroller) may be configured to control the operation of at least die 110 of the die stack 102i via the rigid-flexible circuit 106c.

[0060] The rigid-flexible circuit 106c may include rigid regions 120e to 120g alternating with the flexible portions 122d to 122e. The rigid region 120f may be substantially or approximately the same length as the rigid regions 120e and 120g.

[0061] As previously discussed, die stack 102i can be mounted on rigid region 120e and attached to electrical connector 112, such that dies 110 are connected to each other. Electrical connector 112l and / or other connectors transmit signals to / from one of the dies 110 and rigid-flexible circuit 106c at wire engagement 146e.

[0062] The controller die 400a is mounted to the rigid region 120g of the rigid-flexible circuit 106c via an accessible wire bonding connection 146f, which communicates with one or more interconnect layers within the rigid-flexible circuit 106c that transmit signals. A molding material 404a may then be applied to cover the controller die 400a. Alternatively, the controller die 400a may be pre-molded with the molding material 404a prior to attachment to the rigid-flexible circuit 106c. In some cases, one or more electrical connectors may connect the controller die 400a to the wire bonding connection 146f. In other cases, the controller die 400a may be interconnected, for example, via vias (not shown) to one or more internal signal transmission layers (e.g., interconnect layers) in a layer stack within the rigid-flexible circuit 106c. Thus, in some embodiments, communication between the die 110 of the die stack 102i and the controller die 400a may be achieved through one or more layers of the rigid-flexible circuit 106c. This provides the advantage of freeing up space within substrate 142 that may have previously been used for signal routing between die stack 102i and controller die 400a.

[0063] Figure 4BA rigid-flexible circuit 106c, according to an embodiment of the invention, is bent to position a die stack 102i above a controller die 400a to form a generally vertically aligned assembly 140c. The rigid-flexible circuit 106c may be bent at a flexible portion 122e to extend substantially vertically in proximity to the molding material 404a. The flexible portion 122e may have a length that accommodates the height of the molding material 404a. The rigid-flexible circuit 106c bends to extend a rigid region 120f along the top surface of the molding material 404a. The rigid-flexible circuit 106c is again bent at a flexible portion 122d to position the rigid region 120e above the rigid region 120f.

[0064] Figure 4C This demonstrates an embodiment of the invention, mounted onto a substrate 142 of a stack 406 having other components. Figure 4B The vertically aligned assembly 140c. In some embodiments, stack 406 may include multiple DRAM dies, while die stack 102i includes NAND dies. Rigid-flexible circuit 106c transmits signals associated with die stack 102i and controller die 400a to / from wire bonding connection point 146f. Electrical connector 112m connects wire bonding connection point 146f on rigid-flexible circuit 106c to wire bonding connection point 146g on substrate 142.

[0065] Figure 4D A semiconductor device 100d according to an embodiment of the present invention is described, wherein a controller die 400b is mounted on the side of a rigid-flexible circuit 106d opposite to a die stack 102j. For example, the die stack 102j is mounted to a first side 104b of the rigid-flexible circuit 106d, and the controller die 400b is mounted to a second side 108b of the rigid-flexible circuit 106d. In this embodiment, the rigid-flexible circuit 106b may be shorter (compared to...). Figure 4A Compared to the rigid-flexible circuit 106c, it has fewer alternating rigid regions 120 and flexible portions 122. For example, the rigid-flexible circuit 106d may include two rigid regions 120i to 120j with a flexible portion 122f between them. The rigid-flexible circuit 106d can be bent in the direction of arrow 124d to vertically align the rigid regions 120i to 120j with each other, thereby forming a flexible portion 122f. Figure 4C The vertically aligned assembly 140c is similar to the vertically aligned assembly 140. The vertically aligned assembly 140 can be mounted on the substrate 142, such as... Figure 1C and 4C As discussed in the text.

[0066] Figure 5AThis describes a semiconductor device 100e according to an embodiment of the present invention, having three die stacks 102k to 102m mounted on alternating sides of a rigid-flexible circuit 106e. The three die stacks 102k to 102m are mounted on rigid regions 120 alternating with two flexible portions, as previously discussed. Spacers 118g to 118h are attached to the top sides 114d to 114e of the die stacks 102k to 102l, respectively. Spacer 118i is attached to the side of the rigid-flexible circuit 106e opposite to the die stack 102m. An electrical connector 112 may be attached between the die 110, the die stacks 102k to 102m, and the rigid-flexible circuit 106e, as previously described. Figure 1A As discussed in the text.

[0067] The rigid-flexible circuit 106e can be bent in the direction of arrow 124e to vertically align the die stacks 102k to 102l. When bent, the spacer 118h can be mechanically connected to the rigid-flexible circuit 106e.

[0068] The die stack 102n can be mounted on the substrate 142, and the electrical connector 112 can be attached between the die 110, the die stack 102n, and the substrate 142, such as... Figure 3 As discussed previously, the semiconductor device 100e can be attached to or mounted on the substrate 142, thereby positioning the spacer 118i for mechanical connection with the top side 114f of the die stack 102n, as described above. Figure 5B As shown in the diagram. When bent, the rigid-flexible circuit 106e forms a vertically aligned assembly 140d and is combined with the die stack 102n to form the vertically aligned assembly 140e. The rigid-flexible circuit 106e can be electrically connected to the substrate 142 via an electrical connector 112n.

[0069] The technical advantage of the side-by-side embodiment is that the die stack 102, the controller die (not shown), and / or other components can be mounted to the rigid-flexible circuit 106 and subsequently attached to the die stack 102 (e.g., die stack 102n) or other components that do not communicate through the rigid-flexible circuit 106e, such as... Figure 5BAs shown in the diagram. Signals to / from die stacks 102k to 102m are transmitted to substrate 142 via rigid-flexible circuitry 106e and electrical connectors 112n, thereby providing the benefit of reducing the routing space on substrate 142 previously required for signals associated with die stacks 102k to 102m. Signals to / from die stack 102n are transmitted to substrate 142 via electrical connectors 112o to 112p, each of which transmits information for a plurality of dies 110 in die stack 102n. As with other embodiments herein, it should be understood that other numbers of dies 110 may be used to form die stack 102, and different numbers of die stacks 102 may be vertically aligned and / or positioned very close to each other. In addition, the rigid-flexible circuit 106 may be configured to mechanically interface with different numbers of die stacks 102 and / or other components mounted to the substrate 142 (e.g., two side-by-side die stacks 102 or die stacks 102 positioned close to the controller die 400).

[0070] Figure 5C Top view 130b and bottom view 132b show a rigid-flexible circuit 106e having die stacks 102k to 102m and attached spacers 118g to 118i. The die stacks 102k to 102m can be mounted to the rigid-flexible circuit 106e, as previously discussed. As shown, the spacers 118g to 118i are attached to the surface of the rigid region 120k of the rigid-flexible circuit 106e or to the top sides 114d to 114e of the die stacks 102k to 102l, as... Figure 5A As shown in the figure. It should be understood that spacer 118 can be mounted to any of the surfaces, including substrate 142, to provide mechanical separation of applicable components.

[0071] Figures 6A to 6C The embodiments of the present invention illustrate the use of jigs to assemble the semiconductor device 100. In some embodiments, strips of laminated material may be formed individually before the components are attached to the rigid-flexible circuit 106. Multiple individual strips of laminated material may be held in place by a single sheet of material.

[0072] Figure 6A Multiple semiconductor devices 100 are shown that can be held in place by support material 600. Individual dies 110, die stacks 102, spacers 118, and / or other components such as controller dies 400 may be attached to rigid-flexible circuitry 106. In some cases, die stacks 102 are formed on rigid-flexible circuitry 106, while in others, die stacks 102 are pre-formed individually and subsequently attached.

[0073] Figure 6A The bare die stack assembly shown corresponds to Figure 1AThe semiconductor device 100a has a first side 104a. Die stacks 102a and 102c are mounted on rigid regions 120a and 120c, respectively, and spacer 118b is mounted on rigid region 120b. Flexible portions 122a to 122c alternate with rigid regions 120a to 120d. In some cases, a die attachment tool may be used, for example, to mount the die 110 on the lower half of the die stacks 102a and 102c. A wire bonding tool may then attach an electrical connector 112 to the mounted die 110. This process may be repeated to mount the upper half of the die stacks 102a and 102c and attach the electrical connector 112. In other embodiments, the electrical connector may be attached after all components are attached to the first side of the rigid-flexible circuit 106. Therefore, the die stacks 102a and 102c can undergo parallel die attachment and wire bonding steps, thereby providing the advantage of minimizing the number of iterations required to assemble the die stack 102 onto the rigid-flexible circuit 106.

[0074] After the components and the required mechanical and electrical connections are completed, it can be used as follows: Figure 6B The fixture 602 shown is applied to material 600. Figure 6C The display has been rotated or flipped so that components (e.g., die stacks 102b and 102d and spacers 118a and 118c) can be mounted to the second side 108 of semiconductor device 100a along with interconnect connector 112, as discussed above. Figure 6A The assembly is complete. Once all components are in place and electrical / mechanical connections are established, the semiconductor device 100 can be separated from or monolithized from the material 600. It should be understood that other assembly processes are included, including assembling the semiconductor device 100 individually, manually, by machine, or in larger separable wafers, and the embodiments are not limited to this. Figures 6A to 6C The assembly / manufacturing process shown in the document.

[0075] Figure 7 This is a flowchart illustrating a method for manufacturing a semiconductor device. The method includes mounting a first die to a first side of a first rigid region of a rigid-flexible circuit (box 710). The method further includes mounting a second die to a second side of a second rigid region of the rigid-flexible circuit opposite to the first side of the first rigid region (box 720). The flexible portion of the rigid-flexible circuit is bent approximately 180 degrees so that the first and second rigid regions are substantially vertically aligned with each other (box 730).

[0076] The above reference Figures 1A to 7 Any of the described semiconductor devices, assemblies, and / or packages can be incorporated into any of numerous larger and / or more complex systems, with representative examples being... Figure 8System 800 is schematically shown. System 800 may include a semiconductor device assembly 810, a power supply 820, a driver 830, a processor 840, and / or other subsystems or components 850. Semiconductor device assembly 810 may include features substantially similar to those of the semiconductor device assembly described above. The resulting system 800 can perform any of a wide variety of functions, such as memory storage, data processing, and / or other suitable functions. Thus, representative system 800 may include, but is not limited to, handheld devices (e.g., mobile phones, tablet computers, digital readers, and digital audio players), computers, vehicles, and other machines and electrical appliances. The components of system 800 may be housed in a single unit or distributed above multiple interconnected units (e.g., via a communication network). The components of system 800 may also include remote devices and any of a wide variety of computer-readable media.

[0077] It should be understood from the foregoing that specific embodiments of the present technology have been described herein for illustrative purposes, but various modifications may be made without departing from this disclosure. Therefore, the present technology is not limited to the appended claims. Furthermore, certain aspects of the new technology described in the context of specific embodiments may be combined or removed in other embodiments. Moreover, although advantages associated with certain embodiments of the new technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments are intended to exhibit such advantages to fall within the scope of the present technology. Therefore, this disclosure and related technologies may cover other embodiments not explicitly shown or described herein.

Claims

1. A semiconductor device comprising: A rigid-flexible circuit having a first rigid region and a second rigid region electrically connected by a flexible portion, wherein the first rigid region, the second rigid region and the flexible portion share a common continuous core layer and one or more common continuous conductive layers, and wherein each of the first rigid region and the second rigid region includes solder resist material on its opposite sides, and the flexible portion does not contain the solder resist material. The first bare plate is mounted to the first side of the first rigid region; as well as A second die is mounted to a second side of the second rigid region, the first side and the second side being located on opposite sides of the rigid-flexible circuit, wherein the flexible portion is bent to hold the first rigid region and the second rigid region in a generally vertically aligned manner with each other.

2. The semiconductor device of claim 1, wherein the first rigid region further comprises at least one bonding pad on the first side.

3. The semiconductor device of claim 1, further comprising a first electrical connector electrically coupling the first die to the rigid-flexible circuit within the first rigid region.

4. The semiconductor device according to claim 1, further comprising: A packaging substrate coupled to a first side of the second rigid region; as well as A second electrical connector electrically couples the packaging substrate to the rigid-flexible circuit within the second rigid region.

5. The semiconductor device of claim 1, further comprising a third die mounted above at least a portion of the exposed side of the first die.

6. The semiconductor device of claim 5, further comprising at least one electrical connector connecting the first die and the third die.

7. A semiconductor device comprising: A rigid-flexible circuit having a first rigid region and a second rigid region electrically connected by a flexible portion, wherein the first rigid region, the second rigid region and the flexible portion share a common continuous core layer and one or more common continuous conductive layers, and wherein each of the first rigid region and the second rigid region includes solder resist on its opposite sides, the flexible portion does not contain the solder resist, wherein each of the first rigid region and the second rigid region has at least one bonding pad thereon, and wherein the flexible portion is configured to bend about 180 degrees to hold the first rigid region and the second rigid region in a substantially vertical alignment with each other; A first die is mounted to a first side of the first rigid region, and the first die is electrically connected to the at least one bonding pad on the first rigid region. A second die is mounted to a second side of the second rigid region, and the second die is electrically connected to at least one bonding pad on the second rigid region, wherein the first side of the first rigid region and the second side of the second rigid region are located on opposite sides of the rigid-flexible circuit; A packaging substrate, which is connected to the rigid-flexible circuit when the rigid-flexible circuit is bent to make the first die and the second die substantially vertically aligned; and An electrical connector that connects the rigid-flexible circuit and the substrate.

8. The semiconductor device of claim 7, wherein the rigid-flexible circuit further includes a third rigid region and a second flexible portion electrically connecting the third rigid region to the second rigid region, wherein the second flexible portion is bent at approximately 180 degrees to keep the first rigid region, the second rigid region and the third rigid region substantially vertically aligned with each other.

9. The semiconductor device of claim 7, wherein the rigid-flexible circuit includes an interconnect layer extending along at least a portion of the length of the rigid-flexible circuit, at least a portion of the interconnect layer being electrically connected to at least one of the bonding pads.

10. The semiconductor device of claim 9, further comprising: A third die stack is mounted to the third rigid region of the rigid-flexible circuit; as well as At least one second electrical connector, which couples at least one die in the third die stack to the rigid-flexible circuit.

11. The semiconductor device of claim 7, further comprising at least a third die mounted over at least a portion of the first die to form a die stack.

12. The semiconductor device of claim 7, further comprising a spacer that separates the exposed side of the second die from the second side of the first rigid region when the rigid-flexible circuit is bent to hold the first rigid region and the second rigid region in a substantially vertically aligned manner with each other.

13. The semiconductor device of claim 12, wherein the spacer is mounted to the exposed side of the second die or to the rigid-flexible circuit.

14. The semiconductor device of claim 7, further comprising: A third die stack is mounted to the substrate, the third die stack comprising at least one die; as well as At least one second electrical connector couples at least some of the dies in the third die stack to the substrate, the third die stack being positioned between the substrate and at least a portion of the rigid-flexible circuit.

15. The semiconductor device of claim 7, further comprising: A plurality of dies are mounted on top of the first die to form a first die stack, and the first die and the plurality of dies are electrically connected to each other. as well as A second plurality of dies are mounted on top of the second die to form a second die stack, the second die and the second plurality of dies being electrically connected to each other.

16. The semiconductor device of claim 7, wherein the first die and the second die are each one of a semiconductor die, a controller die, a molded controller die, or a memory die.

17. A method for forming a semiconductor device, comprising: A rigid-flexible circuit is provided, having a first rigid region and a second rigid region electrically connected by a flexible portion, wherein the first rigid region, the second rigid region, and the flexible portion share a common continuous core layer and one or more common continuous conductive layers, and wherein each of the first rigid region and the second rigid region includes solder resist material on its opposite sides, while the flexible portion does not contain the solder resist material. The first bare die is mounted to the first side of the first rigid region of the rigid-flexible circuit; The second die is mounted to the second side of the second rigid region of the rigid-flexible circuit, opposite to the first side of the first rigid region; and The flexible portion is bent about 180 degrees so that the first rigid region and the second rigid region are substantially vertically aligned with each other, and the flexible portion extends between the first rigid region and the second rigid region.

18. The method of claim 17, further comprising electrically connecting the first die and the second die to the first rigid region and the second rigid region, respectively.

19. The method of claim 17, further comprising mounting a plurality of dies over at least a portion of the first die to form a die stack.

20. The method of claim 19, further comprising electrically connecting the plurality of dies and the first die together.

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