Interconnect structure with redundant electrical connectors and related systems and methods
阅读说明:本技术 具有冗余电连接器的互连结构及相关系统与方法 (Interconnect structure with redundant electrical connectors and related systems and methods ) 是由 安尼库玛·查杜鲁 于 2015-05-22 设计创作,主要内容包括:本发明涉及具有冗余电连接器的互连结构及相关系统与方法。本发明揭示具有含冗余电连接器的互连结构的半导体裸片组合件。在一个实施例中,半导体裸片组合件包含第一半导体裸片、第二半导体裸片及介于所述第一半导体裸片与所述第二半导体裸片之间的互连结构。所述互连结构包含耦合到所述第一半导体裸片的第一导电膜及耦合到所述第二半导体裸片的第二导电膜。所述互连结构进一步包含在所述第一导电膜与所述第二导电膜之间延伸且经由所述第一导电膜而彼此电耦合的多个冗余电连接器。(The invention relates to an interconnection structure with redundant electrical connectors and related systems and methods. Semiconductor die assemblies having interconnect structures with redundant electrical connectors are disclosed. In one embodiment, a semiconductor die assembly includes a first semiconductor die, a second semiconductor die, and an interconnect structure between the first semiconductor die and the second semiconductor die. The interconnect structure includes a first conductive film coupled to the first semiconductor die and a second conductive film coupled to the second semiconductor die. The interconnect structure further includes a plurality of redundant electrical connectors extending between the first and second conductive films and electrically coupled to each other via the first conductive film.)
1. A semiconductor die assembly, comprising:
a first semiconductor die comprising a dielectric material, the dielectric material being located over the first semiconductor die;
a second semiconductor die; and
an interconnect structure coupling the first semiconductor die to the second semiconductor die, wherein the interconnect structure is between the first semiconductor die and the second semiconductor die, and wherein the interconnect structure comprises
A first conductive film coupled to the first semiconductor die,
a second conductive film coupled to the second semiconductor die, an
A plurality of redundant electrical connectors extending between the first and second conductive films and electrically coupled to each other via the first conductive film,
wherein each of the redundant electrical connectors comprises a continuous conductive pillar directly connected to the first conductive film and extending through a portion of the dielectric material to a location spaced from the portion of the dielectric material.
Technical Field
The disclosed embodiments relate to interconnect structures formed between stacked semiconductor dies in a semiconductor die assembly. In several embodiments, the present invention relates to an interconnect structure with redundant conductive connectors.
Background
Packaged semiconductor dies, which include memory chips, microprocessor chips, and imager chips, typically include a semiconductor die mounted on a substrate and enclosed in a plastic protective cover. The die includes functional features, such as memory cells, processor circuits, and imager devices, and bond pads electrically connected to the functional features. The bond pads may be electrically connected to terminals outside the protective cover to allow the die to be connected to external circuitry.
Within some die packages, semiconductor dies can be stacked on top of each other and electrically connected to each other by interconnects placed between adjacent dies. Metal solders may be used to connect interconnects to bond pads of adjacent dies. However, one challenge of metal solder bonding is: metal solders cannot always be properly bonded to interconnects and/or bond pads. As a result, the interconnects may be open-circuited, which may cause the die package to fail to function properly. This in turn can reduce process yield during manufacturing.
Disclosure of Invention
In one aspect, the present disclosure relates to a semiconductor die assembly comprising: a first semiconductor die; a second semiconductor die; and an interconnect structure coupling the first semiconductor die to the second semiconductor die, wherein the interconnect structure is between the first semiconductor die and the second semiconductor die, and wherein the interconnect structure includes-a first conductive film coupled to the first semiconductor die, a second conductive film coupled to the second semiconductor die, and a plurality of redundant electrical connectors extending between the first conductive film and the second conductive film and electrically coupled to each other via the first conductive film.
In another aspect, the present disclosure relates to a semiconductor die assembly comprising: a first semiconductor die having first conductive traces; a second semiconductor die having second conductive traces; and a plurality of redundant electrical connectors extending between the first conductive trace and the second conductive trace, wherein each of the redundant electrical connectors includes a conductive member coupled to the first conductive trace, wherein the conductive member includes an end portion, and a conductive bonding material between the conductive member and the second conductive trace, wherein the conductive bonding material is bonded to the end portion of the conductive member.
In another aspect, the present disclosure relates to a semiconductor die assembly comprising: a first semiconductor die having conductive traces; a second semiconductor die; and a plurality of conductive members coupled to the conductive traces and extending vertically toward the second semiconductor die, wherein the conductive members are electrically coupled to each other via the conductive traces, and wherein at least one of the conductive members is coupled to the second semiconductor die.
In another aspect, the present disclosure relates to a method of forming a semiconductor die assembly, the method comprising: forming a first conductive film on the first semiconductor die; forming a second conductive film on the second semiconductor die; forming a plurality of redundant electrical connectors on the first conductive film; and coupling the redundant electrical connector to the second conductive film.
In another aspect, the present disclosure relates to a method of forming a semiconductor die assembly, comprising: forming a first conductive trace on a first semiconductor die; forming a plurality of conductive members on the first conductive traces protruding away from the first semiconductor die; disposing a conductive bonding material on each of the conductive members; and reflowing the conductive bonding material to couple individual ones of the plurality of conductive members to second conductive traces of a second semiconductor die.
Drawings
Figure 1 is a cross-sectional view of a semiconductor die assembly configured according to an embodiment of the invention.
Figure 2A is an enlarged cross-sectional view of a semiconductor device including an interconnect structure configured in accordance with an embodiment of the present invention.
Fig. 2B is a cross-sectional view illustrating certain failure modes of solder bonding that may occur during manufacturing.
Figure 3 is a top plan view showing an interconnect structure configured according to another embodiment of the present invention.
Figures 4A-4H are cross-sectional views illustrating a semiconductor device in various stages of a method for fabricating an interconnect structure according to selected embodiments of the invention.
Figure 5 is a schematic diagram of a system including a semiconductor die assembly configured according to an embodiment of the invention.
Detailed Description
Specific details of several embodiments of stacked semiconductor die assemblies having interconnect structures with redundant electrical connectors and related systems and methods are described below. The terms "semiconductor device" and "semiconductor die" generally refer to solid state devices, such as logic devices, memory devices, or other semiconductor circuits, components, and the like, that include semiconductor materials. Furthermore, the terms "semiconductor device" and "semiconductor die" may refer to an assembly or other structure in various stages of processing before, or to become, a finished device. The term "substrate" may refer to either a wafer level substrate or a singulated die level substrate, depending on the context in which the term is used. One skilled in the relevant art will recognize that suitable steps of the methods described herein may be performed at the wafer level or die level. Furthermore, conventional semiconductor fabrication techniques may be used to form the structures disclosed herein, if the context does not dictate otherwise. Materials may be deposited, for example, using chemical vapor deposition, physical vapor deposition, atomic layer deposition, spin-on coating, and/or other suitable techniques. Similarly, material may be removed, for example, using plasma etching, wet etching, chemical mechanical planarization, or other suitable techniques. One skilled in the relevant art will also appreciate that the invention can have additional embodiments, and that the invention can be practiced without several of the details of the embodiments described below with reference to fig. 1-5.
As used herein, the terms "vertical," "lateral," "up," and "down" may refer to the relative directions or positions of features in a semiconductor die assembly in view of the orientations shown in the figures. For example, "up" or "uppermost" may refer to a feature being positioned closer to the top of the page than another feature. However, these terms should be broadly construed to include semiconductor devices having other orientations.
Figure 1 is a cross-sectional view of a semiconductor die assembly 100 ("assembly 100") configured according to an embodiment of the invention. The assembly 100 includes a stack of first semiconductor dies 102a (collectively "semiconductor dies 102") carried by second semiconductor dies 102 b. The second semiconductor die 102b is in turn carried by the interposer 120. The interposer 120 may include, for example, a semiconductor die, a dielectric spacer, and/or another suitable substrate having electrical connectors (not shown), such as vias, metal traces, and the like, connected between the interposer 120 and the package substrate 125. The package substrate 125 may include, for example, an interposer, a printed circuit board, another logic die, or another suitable substrate that connects to package contacts 127 (e.g., bond pads) and electrical connectors 128 (e.g., solder balls) that electrically couple the assembly 100 to external circuitry (not shown). In some embodiments, the package substrate 125 and/or interposer 120 may be configured differently. For example, in some embodiments, the interposer 120 may be omitted and the second semiconductor die 102b may be directly connected to the package substrate 125.
The assembly 100 may further include a thermally conductive casing 110 ("casing 110"). The casing 110 can include a cover portion 112 and a wall portion 113 attached to the cover portion 112 or integrally formed with the cover portion 112. The lid portion 112 can be attached to the topmost first semiconductor die 102a by a first bonding material 114a (e.g., an adhesive). The wall portion 113 can extend vertically away from the lid portion 112 and be attached to the peripheral portion 106 of the first semiconductor die 102a (referred to by those skilled in the art as a "porch" or "pedestal") by a second bonding material 114b, such as an adhesive. In addition to providing a protective cover, the casing 110 can act as a heat sink to absorb thermal energy and dissipate the thermal energy from the semiconductor die 102. Accordingly, the casing 110 may be made of a thermally conductive material (e.g., nickel (Ni), copper (Cu), aluminum (Al), a ceramic material with high thermal conductivity (e.g., aluminum nitride), and/or other suitable thermally conductive materials).
In some embodiments, the first bonding material 114a and/or the second bonding material 114b may be made of a material known in the art as a "thermal bonding material" or "TIM" (which is designed to increase the contact thermal conductivity at a surface junction, such as between a die surface and a heat spreader). The TIM may comprise a silicone-based grease, gel, or adhesive doped with a conductive material (e.g., carbon nanotubes, solder material, diamond-like carbon (DLC), etc.) and a phase change material. In other embodiments, the first bonding material 114a and/or the second bonding material 114b may comprise other suitable materials, such as metals (e.g., copper) and/or other suitable thermally conductive materials.
Some or all of the first and/or second semiconductor dies 102 can be at least partially encapsulated in the dielectric underfill material 116. Underfill material 116 may be deposited or otherwise formed around some or all of the dies and/or between some or all of the dies to enhance mechanical connection with the dies and/or to provide electrical isolation between conductive features and/or structures, such as interconnects. The underfill material 116 may be a non-conductive epoxy paste, a capillary underfill material, a non-conductive film, a molded underfill material, and/or include other suitable electrically insulating materials. In several embodiments, the underfill material 116 can be selected based on the thermal conductivity of the underfill material 116 to enhance heat dissipation through the dies of the assembly 100. In some embodiments, the underfill material 116 can be used in place of the first bonding material 114a and/or the second bonding material 114b to attach the casing 110 to the topmost first semiconductor die 102 a.
The semiconductor dies 102 can each be formed from a semiconductor substrate, such as silicon, silicon-on-insulator, compound semiconductor (e.g., gallium nitride), or other suitable substrate. The semiconductor substrate may be cut or singulated into semiconductor dies having any of a variety of integrated circuit components or functional features, such as Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), flash memory, or other forms of integrated circuit devices, including memory, processing circuitry, imaging components, and/or other semiconductor devices. In selected embodiments, the assembly 100 can be configured as a Hybrid Memory Cube (HMC) in which the first semiconductor die 102a provides data storage (e.g., DRAM die) and the second semiconductor die 102b provides memory control (e.g., DRAM control) within the HMC. In some embodiments, the assembly 100 may include other semiconductor dies in addition to and/or in place of one or more of the semiconductor dies 102. Such semiconductor die may include, for example, integrated circuit components other than data storage and/or memory control components. Further, although the assembly 100 includes 9 dies stacked on the interposer 120, in other embodiments, the assembly 100 can include less than 9 dies (e.g., 6 dies) or more than 9 dies (e.g., 12 dies, 14 dies, 16 dies, 32 dies, etc.). For example, in an embodiment, the assembly 100 may include 4 memory dies stacked on 2 logic dies. Furthermore, in various embodiments, the semiconductor die 102 may have different dimensions. For example, in some embodiments, the second semiconductor die 102b can have the same footprint as at least one of the first semiconductor dies 102 a.
As further shown in fig. 1, the assembly 100 further includes: a plurality of first conductive traces 140a ("first traces 140 a") located on a first side 109a (e.g., front side) of the semiconductor die 102; a plurality of second conductive traces 140b ("second traces 140 b") located on a second side 109b (e.g., a back side) of the semiconductor die 102; and a plurality of interconnect structures 130 that couple respective first traces 140a and respective second traces 140b to one another. Each of the first and second traces 140a, 140b can include, for example, a conductive line, conductive plate, or other conductive structure that extends laterally across a side of the semiconductor die 102. In the illustrated embodiment, the first and second wire traces 140a and 140b are coupled to corresponding Through Substrate Vias (TSVs) 142. The TSVs are configured to couple the first and second traces 140a, 140b at opposite sides of the semiconductor die 102 to one another. As shown in the figure, the TSV 142 can be disposed toward the center of the semiconductor die 102, and the first and second traces 140a and 140b can flare outward from the TSV 142 and toward the interconnect structure 130. However, in other embodiments, the TSVs 142, the first and second wire traces 140a, 140b, and/or the interconnect structure 130 may be arranged differently.
The interconnect structures 130 can each include a plurality of redundant electrical connectors 134 ("redundant connectors 134") coupled between individual first traces 140a and individual second traces 140b of adjacent semiconductor dies 102. Thus, the first and second traces 140a, 140b of each pair are electrically and thermally coupled together by a plurality of redundant connectors 134. In one aspect of this embodiment, the redundant connector 134 can improve process yield during manufacturing. For example, as described in more detail below, the individual structures 130 are less prone to open circuits relative to conventional interconnects or other electrical connectors because there are multiple redundant connectors spaced from each other along the traces 140a and 140 b. In another aspect of this embodiment, the redundant connector 134 can enhance thermal conduction through the stack of semiconductor dies 102 and toward the lid portion 112 of the casing 110. In particular, the redundant connectors 134 may provide multiple thermal transfer paths between adjacent semiconductor dies 102. In several embodiments, the redundant connectors 134 may be spaced apart from each other along the individual traces 140a and 140b to laterally dissipate heat across the semiconductor die 102. In additional or alternative embodiments, additional redundant electrical connectors 138 (shown in phantom) may extend between inner portions (e.g., between TSVs 142) and/or outer portions (e.g., toward the edge of die 102) of semiconductor die 102 to further dissipate heat.
Fig. 2A is an enlarged view of a semiconductor device 205 having an interconnect structure 230 configured in accordance with an embodiment of the invention. As shown in the figure, the interconnect structure 230 includes a plurality of redundant electrical connectors 234 ("redundant connectors 234") extending between a first semiconductor substrate 204a (e.g., a semiconductor wafer or die) and a second semiconductor substrate 204b (e.g., a semiconductor wafer or die). Each of the redundant connectors 234 includes a conductive member or post 232 coupled to a first conductive film or first trace 240a of the first substrate 204 a. The redundant connector 234 also includes a second conductive member or bond pad 233 (e.g., a bump bond pad) coupled to a second conductive film or second trace 240b on the second substrate 204 b. The conductive bonding material 235 may form a conductive joint coupling the bonding pad 233 to the end portion 237 of the corresponding pillar 232. The conductive bonding material 235 may comprise, for example, solder (e.g., metal solder), conductive epoxy, or conductive paste.
In general, one challenge with solder bonding materials is: it fails to properly bond the interconnects to the bond pads. For example, fig. 2B shows several failure modes of solder bonding material 295. First failure mode F1Occurs when the interconnects 292 have a height that is less than the height of adjacent interconnects (not shown). In this failure mode, the larger gap between the interconnects 292 and their corresponding bond pads 293 prevents the bonding material 295 from contacting the bond pads 293. Second failure mode F2Residual contaminants (not shown) that occur on the interconnects 292 and/or the bond pads 293 prevent the bonding material 295 from wetting to the interconnects 292 and/or the bond pads 293. Third failure mode F3Can be attributed to solder wicking that occurs during reflow or other heating processes. In particular, solder wicking occurs when surface tension attracts (heated) the bonding material 295 toward the sidewalls 296 of the interconnects 292 and away from the bond pads 293. Fourth failure mode F4Involving cracking or breaking of the bonding material 295 between the interconnects 292 and the bond pads 293. Cracking can occur, for example, when the solder material consumes (i.e., reacts with) certain materials of the interconnect, such as palladium (Pd), and causes the bonding material 295 to become brittle and prone to cracking.
However, interconnect structures configured according to several embodiments of the present disclosure may address these and other limitations of conventional interconnects and related structures. Referring again to FIG. 2A, the redundant connectors 234 are configured such that even if some of the connectors 234 fail (e.g., by failure mode F)1To F4One of the other redundant connectors 234), the interconnect structure 230 will not fail as long as at least one of the other redundant connectors 234 remains connected to the first and second traces 240a, 240 b. In the embodiment shown in FIG. 2A, for example, up to 4 redundant connectors 234 may be disabled and the interconnect structure not disabled230 are open. In other embodiments, the interconnect structure 230 may have a different number of redundant connectors, such as more than 5 redundant connectors (e.g., 6, 8, 10, or more than 10 connectors) or less than 5 redundant connectors (e.g., 2, 3, or 4 connectors). In several embodiments, the number of redundant connectors can be selected to improve the expected process yield during manufacturing. For example, in some examples, an interconnect structure with 3 redundant connectors may increase process throughput by 0.5%, while 4 redundant connectors may only increase throughput by an additional 0.05%. In this scenario, the 3-connector configuration may be a more acceptable design than the 4-connector configuration because the expected difference in process yield is negligible.
Another advantage of the interconnect structure of various embodiments is that: the redundant electrical connector can reduce current density through the conductive joint (e.g., through the bonding material 235 of the redundant interconnect 234). For example, an interconnect structure with 10 redundant connectors may reduce the current density through each of its conductive contacts by a factor of about 10. The related advantages are that: lower current densities may reduce electromigration. For example, lower current densities may reduce electromigration through tin/silver-based (SnAg) solder joints, which are typically more susceptible to electromigration than other interconnect materials, such as copper. In some embodiments, the number of redundant electrical connectors may be selected to achieve some reduction in electromigration balanced with a potential increase in capacitance across the interconnect structure.
Further advantages of the interconnect structure of various embodiments are: the redundant electrical connectors may be closely packed. For example, fig. 3 is a top plan view showing a close-packed redundant electrical connector 334 ("redundant connector 334") of a corresponding interconnect structure 330 configured according to another embodiment of the invention. As shown in the figure, the redundant connectors 334 are each formed on a conductive trace 340 of a corresponding interconnect structure 330. The redundant connectors 334 each have a diameter d1And are spaced apart from each other by a spacing distance s1. In one embodiment, the diameter d1May be approximately the same size as the spacing distance s1. In another embodiment, the separation distance s1Can be smaller than the diameterd1. For example, the separation distance s1Can be less than d175% of (d) is less than150% of, or less than d125% of the total. In contrast, conventional interconnects cannot be close-packed in this manner because there is a risk that metal solder may bridge the interconnects and cause electrical shorting. However, because the redundant connectors 334 are electrically coupled to each other (i.e., via conductive traces 340), an electrical short does not pose such a risk.
Figures 4A-4H are partial cross-sectional views illustrating the
Figure 4B shows the
Fig. 4C shows the
Fig. 4D shows the
Fig. 4E shows the
Figure 4F shows the
Fig. 4G shows the
Fig. 4H shows the
Any of the interconnect structures and/or semiconductor die assemblies described above with reference to fig. 1-4H may be incorporated into any of a number of larger and/or more complex systems, representative examples of which are the
From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the invention. For example, although several of the embodiments of the semiconductor die assembly are described with respect to an HMC, in other embodiments, the semiconductor die assembly may be configured as other memory devices or other types of stacked die assemblies. Additionally, although certain features or components have been shown in the illustrated embodiments as having certain arrangements or configurations, other arrangements and configurations are possible. For example, although in the illustrated embodiment the TSVs 442 (fig. 4E) are formed after front-end metallization (i.e., after forming the substrate contacts 407), in other embodiments the
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