The present disclosure generally relates to semiconductor device assemblies and more particularly relates to a conductive pad on a through-silicon via (TSV).
Microelectronic devices generally have a die (e.g., a chip) that includes integrated circuitry with a high density of very small components. Typically, dies include an array of bond pads electrically coupled to the integrated circuitry. The bond pads are external electrical contacts through which the supply voltage, signals, etc., are transmitted to and from the integrated circuitry. After dies are formed, they are “packaged” to couple the bond pads to a larger array of electrical terminals that can be more easily coupled to the various power supply lines, signal lines, and ground lines. Conventional processes for packaging dies include electrically coupling the bond pads on the dies to an array of leads, ball pads, or other types of electrical terminals and encapsulating the dies to protect them from environmental factors (e.g., moisture, particulates, static electricity, and physical impact).
Semiconductor devices are integrated in many devices to implement memory cells, processor circuits, imager devices, and other functional features. As more applications for semiconductor devices are discovered, designers are tasked with creating improved devices that can perform a greater number of operations per second, store greater amounts of data, or operate with a higher level of security. To accomplish this task, designers continue to develop new techniques to increase the number of circuit elements on a semiconductor device without simultaneously increasing the size of the device. This development, however, may not be sustainable due to various challenges that arise from designing semiconductor devices with high circuit density. Thus, additional techniques may be required to continue the growth in capability of semiconductor devices.
One such technique is to implement multiple circuit components within a single package. For example, stacked semiconductor devices enable multiple semiconductor dies to be stacked on top of one another to increase the number of circuit elements within a package without increasing its footprint. In some cases, individual semiconductor dies may be stacked on top of one another to produce a vertical stack of semiconductor dies. The semiconductor dies can include through-silicon vias (TSVs) that extend between a front side (e.g., active side at which circuitry is disposed) and a back side opposite the front side. Contact pads may be disposed at the back side of the semiconductor dies in contact with an exposed portion of the TSVs to enable an additional semiconductor die to be electrically coupled thereat. Various techniques exist for disposing contact pads at TSVs, however, some of these techniques may be overly time-consuming or produce semiconductor devices with reliability or cost concerns. An example semiconductor device is shown in
Various techniques may be used to dispose the contact pad 110 of the TSV 108. For example, initially, the TSV 108 may protrude beyond the back side of the substrate 104 (e.g., by more than three microns). A layer of silicon nitride 116 (e.g., low-temperature silicon nitride deposited at a temperature less than 200, 300, or 400 degrees Celsius) may be disposed at the back side of the substrate, along sidewalls of the TSV 108, and over top of the TSV 108. In some cases, the layer of silicon nitride is disposed with a thickness greater than one micron. A layer of oxide (not shown), such as a low-temperature oxide, may then be deposited at the back side of the semiconductor die 102 over the layer of silicon nitride 116. The layer of oxide may be disposed with a thickness of around 0.5 microns (e.g., within. 1 microns, within 0.2 microns, etc.). Material may then be removed from the backside of the semiconductor die 102 through chemical-mechanical planarization (CMP) to expose the TSV 108. For instance, the layer of oxide may be entirely removed and the layer of silicon nitride 116 may be thinned to around one micron (e.g., within 0.1 microns, within 0.2 microns, within 0.5 microns, etc.). In this way, a back side of the semiconductor die 102 may correspond to a planarized layer of silicon nitride 116 with the coupling surface 112 of the TSV 108 exposed.
A layer of silicon carbon nitride 118 (e.g., a high-temperature silicon carbon nitride) can then be disposed at the layer of silicon nitride 116 and over the coupling surface 112 of the TSV 108. The layer of oxide 114 can be disposed at the back side of the semiconductor die 102 over the layer of silicon carbon nitride 118. An additional layer of silicon carbon nitride 120 (e.g., high-temperature silicon carbon nitride) can then be disposed over the layer of oxide 114. The layer of silicon carbon nitride 118, the layer of oxide 114, and the layer of silicon carbon nitride 120 may be etched (e.g., dry etched) to expose the coupling surface 112 of the TSV 108. The contact pad 110 may then be disposed in the opening at the coupling surface 112 such that the contact pad 110 is exposed at the back side of the semiconductor die 102. In doing so, additional semiconductor dies may be stacked onto the semiconductor die 102 and electrically coupled at the contact pad 110.
Using these techniques to dispose a contact pad on a TSV may be suboptimal for any number of reasons. As discussed above, the process may involve multiple deposition steps to dispose various layers at the back side of the semiconductor die 102 (e.g., the layer of silicon nitride 116 or the layer of oxide that is later removed). As a result, implementation of the design process may require a large amount of time and have a large material cost. Moreover, the coupling surface 112 of the TSV 108 may be exposed through CMP, which can result in smearing of the conductive material within the TSV 108 across the back side of the semiconductor die 102 or fracture of the semiconductor die 102. In this way, the use of CMP may reduce the reliability of the semiconductor die 102 or reduce yield. In yet another aspect, the use of CMP in areas that do and do not include the TSV 108 can create topography (e.g., differences in height of up to 200 nanometers) on the back surface of the semiconductor die 102. The topography may result from a tendency of an area that includes the TSV 108 to resist CMP more than an area that does not include the TSV 108. In some cases, this topography can create vulnerabilities in the semiconductor die 102 or make it difficult to stack additional semiconductor dies on the semiconductor die 102. In aspects, the topography can reduce the reliability of metal-metal bonding at the TSV 108 (e.g., due to DC resistance yield). Thus, designing semiconductor devices using these techniques may create semiconductor devices with reliability concerns or require undue cost or manufacture time.
To address these drawbacks and others, various embodiments of the present technology provide semiconductor device assemblies that include a contact pad disposed at a TSV. The semiconductor device includes a substrate having a front side and a back side opposite the front side. A through via extends entirely through the substrate. The through via includes a protruding portion that extends beyond the back side of the substrate. A layer of silicon carbon nitride is disposed at the back side of the substrate and along sidewalls of the protruding portion of the through via. A layer of oxide is disposed at the back side of the substrate and at least partially surrounding the protruding portion of the through via. A conductive pad is disposed at a coupling surface of the through via and at least partially extending through the layer of oxide. As a result, a reliable and cost-efficient semiconductor device can be assembled, an example of which is shown in
In contrast to the semiconductor device assembly 100 illustrated in
The contact pad 210 may be disposed at the back side of the semiconductor die 202 on a coupling surface 212 of the TSV 208. In aspects, the contact pad 210 may be smaller than the coupling surface 212 of the TSV 208 such that the contact pad 210 contacts only a portion of the coupling surface 212. For example, a cross-sectional area of the contact pad 210 in a plane coplanar with the coupling surface 212 is smaller than the area of the coupling surface 212. A surface of the contact pad 210 may be disposed at the back side of the semiconductor die 202 to enable an additional semiconductor die to be stacked on the semiconductor die 202 and electrically coupled with the semiconductor die 202 at the contact pad 210.
Although illustrated and described as a semiconductor die, the semiconductor die 202 could be replaced with a wafer (e.g., semiconductor wafer) implementing multiple semiconductor dies. For example, the substrate 204 could be replaced with a wafer-level or panel-level substrate used to implement multiple semiconductor dies. Moreover, although described as a TSV, the TSV 208 may generally refer to a through-substrate via. As such, the TSV 208 may be implemented through a non-silicon substrate, for example, an organic substrate or other semiconductor substrate. In yet another aspect, although described with reference to particular materials, other materials may be used to form the various layers of the semiconductor die 202. In this way, the layer of oxide 214, the layer of silicon carbon nitride 216, or the layer of silicon carbon nitride 218 may instead include any other material, for example, a different dielectric material (e.g., silicon oxide, silicon nitride, silicon carbide, silicon carbon nitride, or the like).
This disclosure now turns to a series of steps for fabricating semiconductor device assemblies in accordance with embodiments of the present technology. Specifically,
Beginning with
A layer of oxide 214 (e.g., high-temperature silicon oxide) may be disposed at least partially around the protruded portion 220. For example, the layer of oxide 214 can be deposited such that the layer of oxide 214 extends more than 1 micron above the protruded portion 220. The layer of oxide 214 may be disposed at the layer of silicon carbon nitride 216 such that the layer of silicon carbon nitride 216 separates the substrate 204 and the TSV 208 from the layer of oxide 214. An additional layer of silicon carbon nitride 218 may then be disposed at the layer of oxide 214 opposite the layer of silicon carbon nitride 216 (e.g., opposite the substrate 204).
Although in the foregoing example embodiment semiconductor device assemblies have been illustrated and described as including a particular configuration of semiconductor dies, in other embodiments, assemblies can be provided with different configurations of semiconductor dies. For example, the semiconductor device assemblies illustrated in any of the foregoing examples could be implemented with a vertical stack of semiconductor dies (e.g., in accordance with the high bandwidth memory (HBM protocol), multiple stacks of semiconductor dies, a plurality of semiconductor dies, a single semiconductor die, mutatis mutandis.
In accordance with one aspect of the present disclosure, the semiconductor devices illustrated in the assemblies of
Any one of the semiconductor devices and semiconductor device assemblies described above with reference to
At 802, a substrate is provided. The substrate may include a front side, a back side opposite the front side, and a through via extending entirely through the substrate and having a protruding portion that extends beyond the back side of the substrate. At 804, a layer of silicon carbon nitride is disposed at the back side of the substrate and around the protruding portion of the through via. At 806, a layer of oxide is disposed at the back side of the substrate and at least partially surrounding the protruding portion of the through via. At 808, the layer of oxide and the layer of silicon carbon nitride are etched to expose a coupling surface of the through via. At 810, a conductive pad is disposed at the coupling surface of the through via and at least partially extending through the layer of oxide.
Specific details of several embodiments of semiconductor devices, and associated systems and methods, are described above. Depending upon the context in which it is used, the term “substrate” can refer to a wafer-level substrate or to a singulated, die-level substrate. Furthermore, unless the context indicates otherwise, structures disclosed herein can be formed using conventional semiconductor-manufacturing techniques. 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, CMP, or other suitable techniques.
The technology disclosed herein relates to semiconductor devices, systems with semiconductor devices, and related methods for manufacturing semiconductor devices. The term “semiconductor device” generally refers to a solid-state device that includes one or more semiconductor materials. Examples of semiconductor devices include logic devices, memory devices, and diodes, among others. Furthermore, the term “semiconductor device” can refer to a finished device or to an assembly or other structure at various stages of processing before becoming a finished device. Depending upon the context in which it is used, the term “substrate” can refer to a structure that supports electronic components (e.g., a die), such as a PCB or wafer-level substrate, a die-level substrate, or another die for die-stacking or three-dimensional integration (3DI) applications.
The devices discussed herein, including a memory device, may be formed on a semiconductor substrate or die, such as silicon, germanium, silicon-germanium alloy, gallium arsenide, gallium nitride, etc. In some cases, the substrate is a semiconductor wafer. In other cases, the substrate may be a silicon-on-insulator (SOI) substrate, such as silicon-on-glass (SOG) or silicon-on-sapphire (SOP), or epitaxial layers of semiconductor materials on another substrate. The conductivity of the substrate, or sub-regions of the substrate, may be controlled through doping using various chemical species including, but not limited to, phosphorus, boron, or arsenic. Doping may be performed during the initial formation or growth of the substrate by ion-implantation or by any other doping means.
The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. Other examples and implementations are within the scope of the disclosure and appended claims. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.
As used herein, including in the claims, “or” as used in a list of items (for example, a list of items prefaced by a phrase such as “at least one of” or “one or more of”) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an exemplary step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on.”
As used herein, the terms “vertical,” “lateral,” “upper,” “lower,” “above,” and “below” can refer to relative directions or positions of features in the semiconductor devices in view of the orientation shown in the Figures. For example, “upper” or “uppermost” can refer to a feature positioned closer to the top of a page than another feature. These terms, however, should be construed broadly to include semiconductor devices having other orientations, such as inverted or inclined orientations where top/bottom, over/under, above/below, up/down, and left/right can be interchanged depending on the orientation.
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 scope of the invention. Rather, in the foregoing description, numerous specific details are discussed to provide a thorough and enabling description for embodiments of the present technology. One skilled in the relevant art, however, will recognize that the disclosure can be practiced without one or more of the specific details. In other instances, well-known structures or operations often associated with memory systems and devices are not shown, or are not described in detail, to avoid obscuring other aspects of the technology. In general, it should be understood that various other devices, systems, and methods in addition to those specific embodiments disclosed herein may be within the scope of the present technology.
The present application claims priority to U.S. Provisional Patent Application No. 63/465,514, filed May 10, 2023, the disclosure of which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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63465514 | May 2023 | US |