Embodiments of the disclosure are in the field of semiconductor packages and, in particular, the methods and systems a topological crack stop (TCS) passivation layer for integrated circuits.
For the past several decades, the scaling of features in integrated circuits has been a driving force behind an ever-growing semiconductor industry. Scaling to smaller and smaller features enables increased densities of functional units on the limited real estate of semiconductor chips. For example, shrinking transistor size allows for the incorporation of an increased number of memory or logic devices on a chip, lending to the fabrication of products with increased capacity. The drive for ever-more capacity, however, is not without issue. The necessity to optimize the performance of each device becomes increasingly significant.
Variability in conventional and state-of-the-art fabrication processes may limit the possibility to further extend them into the sub-10 nm range. Consequently, fabrication of the functional components needed for future technology nodes may require the introduction of new methodologies or the integration of new technologies in current fabrication processes or in place of current fabrication processes.
A topological crack stop (TCS) passivation layer for integrated circuits is described. In the following description, numerous specific details are set forth, such as specific material and tooling regimes, in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to one skilled in the art that embodiments of the present disclosure may be practiced without these specific details. In other instances, well-known features, such as single or dual damascene processing, are not described in detail in order to not unnecessarily obscure embodiments of the present disclosure. Furthermore, it is to be understood that the various embodiments shown in the Figures are illustrative representations and are not necessarily drawn to scale. In some cases, various operations will be described as multiple discrete operations, in turn, in a manner that is most helpful in understanding the present disclosure, however, the order of description should not be construed to imply that these operations are necessarily order dependent. In particular, these operations need not be performed in the order of presentation.
Certain terminology may also be used in the following description for the purpose of reference only, and thus are not intended to be limiting. For example, terms such as “upper”, “lower”, “above”, “below,” “bottom,” and “top” refer to directions in the drawings to which reference is made. Terms such as “front”, “back”, “rear”, and “side” describe the orientation and/or location of portions of the component within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the component under discussion. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import.
Embodiments described herein may be directed to front-end-of-line (FEOL) semiconductor processing and structures. FEOL is the first portion of integrated circuit (IC) fabrication where the individual devices (e.g., transistors, capacitors, resistors, etc.) are patterned in the semiconductor substrate or layer. FEOL generally covers everything up to (but not including) the deposition of metal interconnect layers. Following the last FEOL operation, the result is typically a wafer with isolated transistors (e.g., without any wires).
Embodiments described herein may be directed to back-end-of-line (BEOL) semiconductor processing and structures. BEOL is the second portion of IC fabrication where the individual devices (e.g., transistors, capacitors, resistors, etc.) are interconnected with wiring on the wafer, e.g., the metallization layer or layers. BEOL includes contacts, insulating layers (dielectrics), metal levels, and bonding sites for chip-to-package connections. In the BEOL part of the fabrication stage contacts (pads), interconnect wires, vias and dielectric structures are formed. For modern IC processes, more than 10 metal layers may be added in the BEOL.
Embodiments described below may be applicable to FEOL processing and structures, BEOL processing and structures, or both FEOL and BEOL processing and structures. In particular, although an exemplary processing scheme may be illustrated using a FEOL processing scenario, such approaches may also be applicable to BEOL processing. Likewise, although an exemplary processing scheme may be illustrated using a BEOL processing scenario, such approaches may also be applicable to FEOL processing.
One or more embodiments described herein are directed to structures and architectures for fabricating a topological crack stop (TCS) passivation layer for integrated circuits. Embodiments may include or pertain to integrated circuits and system-on-chip (SoC) technologies for applications including but not limited to, advanced driver-assistance systems (ADAS).
There is a need for advanced driver-assistance systems (ADAS) chips to have significant reliability capability. Integrated circuits have been influencing a revolution in the field of autonomous vehicles, and semiconductor chips have played central role in enabling this capability. For example, these chips are the brains behind AI that drives such autonomous vehicles. Since an average user utilizes a given vehicle for 10 years, it is pertinent that these chips deliver the performance during that lifetime, particularly with respect to thermal mechanical properties.
The reliability performance for an ADAS chip is tested using temperature cycling (TC) stress, which increases applied stress to the chip to accelerate to identify potential fail mechanisms. Typically, the ADAS chip is required last for at least PC (pre-conditioning) plus 1000 thermal cycles (TCB). However, actual reliability performance data on test vehicles that mimic such chips show fails occurring in the chips significantly before 1000 thermal cycles (e.g., at 150-450 cycles). These fails lead to electrical discontinuity in the integrated circuit rendering the product inoperable.
To provide further context,
Various solutions proposed to solve this issue include: i) use of PI (polyimide) as passivation material, ii) use of smaller die for the product, and iii) removal of a lid from the package. Each solution, however, has disadvantages. For example, the disadvantage of use of PI as passivation material is that current fabrication chemical disposal facilities are not compatible with PI, and it is prohibitively expensive to implement this solution path.
The use of smaller die for the product may reduce thermomechanical stress and hence provide better reliability performance, but typically means less number of features available for designers. Current ADAS chips require server like chips to process vehicle data in real-time, and hence less features makes smaller dies undesirable in ADAS products.
And although lidded products have higher thermomechanical stress than unlidded products because lids constrain the substrate and transfer stress to the die from the substrate, removal of the also leads to reduction in heat conduction from other parts. As a result, the parts runs hot and delivers very low performance.
In accordance with one or more embodiments described herein, integrated circuits suitable for ADAS applications are provided with a crack-arresting feature referred to herein as a topological crack stop (TCS) layer, which arrests crack propagation. The TCS effectively prevents via fails and enables the IC to increase reliability performance to greater than 1000 thermal cycles. Increased reliability performance enables the IC to be used in products in more demanding segments that need stringent reliability requirements such as ADAS, military, etc., while having lower defects per million (DPM). The TCS feature size, pitch and layout can all be tailored and optimized per the product’s BP pitch, circuit performance and reliability needs. Due to this high scalability/tunability of TCS features, the TCS can be integrated into any future technology nodes easily with minimal yield risk. In embodiments, the TCS features can be reused to create functional circuit elements (MIM capacitors, inductors, precision resistors) or process integration aiding features (alignment marks, PRS marks, catch-cups, adhesion improvement to passivation/UF layers).
In accordance with the disclosed embodiments, topological crack stop (TCS) features 216 are formed in the passivation layer 210 and on a top surface of the etch stop layer 208. The TCS features 216 function to arrest a die passivation crack 218 that enters the passivation layer 210 and prevent the die passivation crack 218 from propagating horizontally along the etch stop layer 208 into one of the vias 212. The TCS features 216 effectively prevents via fails and provides the IC 200 with increased reliability performance.
In one embodiment, the passivation layer 210 may comprise an inorganic dielectric materials nitride (e.g., SiN), and the TCS features 216 may comprise an oxide. In embodiments, the TCS features 216 can comprise various inorganic dielectric materials (e.g., SiN, SiC, SiO2, etc.), or the TCS features 216 can comprise organic materials (e.g., PI, PBO, WPR) or combination of thereof. In another embodiment, the TCS features 216 can comprise a metal material (e.g., Cu, Al, W, Ni, etc.) or a combination of metals.
In one embodiment, the height of the TCS features 316 is less than the height of the passivation layer 310. In another embodiment, the height of the TCS features 316 is approximately one-half the height of the passivation layer 310. In yet another embodiment, the height of the TCS features 316 is approximately equal to height of the passivation layer 310. In yet another embodiment, the TCS features 316 may span multiple layers of the IC 300, including extending below the etch stop layer 308 to the FLI 306.
It is to be appreciated that the structures resulting from the above exemplary processing schemes may be used in a same or similar form for subsequent processing operations to complete device fabrication, such as for an ADAS device. As an example of a completed device,
Referring to
In some embodiments, the circuit board 502 may be a printed circuit board (PCB) including multiple metal layers separated from one another by layers of dielectric material and interconnected by electrically conductive vias. Any one or more of the metal layers may be formed in a desired circuit pattern to route electrical signals (optionally in conjunction with other metal layers) between the components coupled to the circuit board 502. In other embodiments, the circuit board 502 may be a non-PCB substrate.
The IC device assembly 500 illustrated in
The package-on-interposer structure 536 may include an IC package 520 coupled to an interposer 504 by coupling components 518. The coupling components 518 may take any suitable form for the application, such as the forms discussed above with reference to the coupling components 516. Although a single IC package 520 is shown, multiple IC packages may be coupled to the interposer 504. It is to be appreciated that additional interposers may be coupled to the interposer 504. The interposer 504 may provide an intervening substrate used to bridge the circuit board 502 and the IC package 520. The IC package 520 may be or include, for example, a die, or any other suitable component. Generally, the interposer 504 may spread a connection to a wider pitch or reroute a connection to a different connection. For example, the interposer 504 may couple the IC package 520 (e.g., a die) to a ball grid array (BGA) of the coupling components 516 for coupling to the circuit board 502. In the embodiment illustrated in
The interposer 504 may be formed of an epoxy resin, a fiberglass-reinforced epoxy resin, a ceramic material, or a polymer material such as polyimide. In some implementations, the interposer 504 may be formed of alternate rigid or flexible materials that may include the same materials described above for use in a semiconductor substrate, such as silicon, germanium, and other group III-V and group IV materials. The interposer 504 may include metal interconnects 510 and vias 508, including but not limited to through-silicon vias (TSVs) 506. The interposer 504 may further include embedded devices, including both passive and active devices. Such devices may include, but are not limited to, capacitors, decoupling capacitors, resistors, inductors, fuses, diodes, transformers, sensors, electrostatic discharge (ESD) devices, and memory devices. More complex devices such as radio-frequency (RF) devices, power amplifiers, power management devices, antennas, arrays, sensors, and microelectromechanical systems (MEMS) devices may also be formed on the interposer 504. The package-on-interposer structure 536 may take the form of any of the package-on-interposer structures known in the art.
The IC device assembly 500 may include an IC package 524 coupled to the first face 540 of the circuit board 502 by coupling components 522. The coupling components 522 may take the form of any of the embodiments discussed above with reference to the coupling components 516, and the IC package 524 may take the form of any of the embodiments discussed above with reference to the IC package 520.
The IC device assembly 500 illustrated in
Depending on its applications, computing device 600 may include other components that may or may not be physically and electrically coupled to the board 602. These other components include, but are not limited to, volatile memory (e.g., DRAM), non-volatile memory (e.g., ROM), flash memory, a graphics processor, a digital signal processor, a crypto processor, a chipset, an antenna, a display, a touchscreen display, a touchscreen controller, a battery, an audio codec, a video codec, a power amplifier, a global positioning system (GPS) device, a compass, an accelerometer, a gyroscope, a speaker, a camera, and a mass storage device (such as hard disk drive, compact disk (CD), digital versatile disk (DVD), and so forth).
The communication chip 606 enables wireless communications for the transfer of data to and from the computing device 600. The term “wireless” and its derivatives may be used to describe circuits, devices, systems, methods, techniques, communications channels, etc., that may communicate data through the use of modulated electromagnetic radiation through a non-solid medium. The term does not imply that the associated devices do not contain any wires, although in some embodiments they might not. The communication chip 606 may implement any of a number of wireless standards or protocols, including but not limited to Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE 802.20, long term evolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE, GSM, GPRS, CDMA, TDMA, DECT, Bluetooth, derivatives thereof, as well as any other wireless protocols that are designated as 3G, 4G, 5G, and beyond. The computing device 600 may include a plurality of communication chips 606. For instance, a first communication chip 606 may be dedicated to shorter range wireless communications such as Wi-Fi and Bluetooth and a second communication chip 606 may be dedicated to longer range wireless communications such as GPS, EDGE, GPRS, CDMA, WiMAX, LTE, Ev-DO, and others.
The processor 604 of the computing device 600 includes an integrated circuit die packaged within the processor 604. In some implementations of the disclosure, the integrated circuit die of the processor includes one or more transistor architectures utilizing IC structures with topological crack stop features, in accordance with implementations of embodiments of the disclosure. The term “processor” may refer to any device or portion of a device that processes electronic data from registers and/or memory to transform that electronic data into other electronic data that may be stored in registers and/or memory.
The communication chip 606 also includes an integrated circuit die packaged within the communication chip 606. In accordance with another implementation of embodiments of the disclosure, the integrated circuit die of the communication chip includes one or more transistor architectures utilizing IC structures with topological crack stop features, in accordance with implementations of embodiments of the disclosure.
In further implementations, another component housed within the computing device 600 may contain an integrated circuit die that includes one or more transistor architectures utilizing IC structures with topological crack stop features, in accordance with implementations of embodiments of the disclosure.
In various implementations, the computing device 600 may be a laptop, a netbook, a notebook, an ultrabook, a smartphone, a tablet, a personal digital assistant (PDA), an ultra mobile PC, a mobile phone, a desktop computer, a server, a printer, a scanner, a monitor, a set-top box, an entertainment control unit, a digital camera, a portable music player, or a digital video recorder. In further implementations, the computing device 600 may be any other electronic device that processes data.
Thus, embodiments described herein include architectures utilizing IC structures with topological crack stop features.
The above description of illustrated implementations of embodiments of the disclosure, including what is described in the Abstract, is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. While specific implementations of, and examples for, the disclosure are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the disclosure, as those skilled in the relevant art will recognize.
These modifications may be made to the disclosure in light of the above detailed description. The terms used in the following claims should not be construed to limit the disclosure to the specific implementations disclosed in the specification and the claims. Rather, the scope of the disclosure is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.
Example embodiment 1: An integrated circuit structure comprises one or more first level interconnects (FLIs) embedded in an underfill (UF) over a substrate. An etch stop layer is over the FLIs. A passivation layer is over the etch stop layer and a plurality of vias are through the passivation layer. A plurality of contacts are on the passivation layer in contact with the vias to connect with the FLI. A plurality of topological crack stop (TCS) features are formed in the passivation layer and on a top surface of the etch stop layer.
Example embodiment 2: The integrated circuit structure of embodiment 1, wherein there is a correlation between a pitch and location of the FLIs and a pitch and location of the TCS features.
Example embodiment 3: The integrated circuit structure of embodiment 1 or 2, wherein the TCS features have a shape that is square, rectangular, domed, saw-toothed, recess domed, trenched, or a combination thereof
Example embodiment 4: The integrated circuit structure of embodiment 1, 2 or 3, wherein at least a portion of the TCS features are spaced apart between neighboring sets of the plurality of vias.
Example embodiment 5: The integrated circuit structure of embodiment 1, 2, 3, or 4, wherein at least a portion of the TCS features are located adjacent to ones of the plurality of vias and directly under corresponding ones of the plurality of contacts.
Example embodiment 6: The integrated circuit structure of embodiment 1, 2, 3, or 4, wherein the passivation layer comprises a nitride and the TCS features comprise an oxide.
Example embodiment 7: The integrated circuit structure of embodiment 1, 2, 3, 4, 5, or 6, wherein at least one of the TCS features incorporates a metal insulator metal (MIM).
Example embodiment 8: The integrated circuit structure of embodiment 1, 2, 3, 4, 5, 6 or 7, wherein at least a portion of the TCS features comprise inductor elements that surround a base of one or more of the plurality of vias, and wherein a diameter of the at least a portion of the TCS features is greater than a diameter of the corresponding contacts located over the at least one of the plurality of vias.
Example embodiment 9: The integrated circuit structure of embodiment 1, 2, 3, 4, 5, 6, 7 or 8, wherein at least a portion of the TCS features are used as in-die alignment features.
Example embodiment 10: The integrated circuit structure of embodiment 1, 2, 3, 4, 5, 6, 7 8, or 9, wherein at least a portion of the TCS features are used as underfill adhesion promoters.
Example embodiment 11: A computing device, comprising a board, and a component coupled to the board. The component includes an integrated circuit structure comprising one or more first level interconnects (FLIs) embedded in an underfill (UF) over a substrate. An etch stop layer is over the FLIs. A passivation layer is over the etch stop layer and a plurality of vias are through the passivation layer. A plurality of contacts are on the passivation layer in contact with the vias to connect with the FLI. A plurality of topological crack stop (TCS) features are formed in the passivation layer and on a top surface of the etch stop layer.
Example embodiment 12: The computing device of embodiment 11, further comprising a memory coupled to the board, and a communication chip coupled to the board.
Example embodiment 13: The computing device of embodiment 11 or 12, further comprising a battery coupled to the board.
Example embodiment 14: The computing device of embodiment 11, 12 or 13, wherein the component is a packaged integrated circuit die.
Example embodiment 15: An integrated circuit structure comprises one or more first level interconnects (FLIs) embedded in an underfill (UF) over a substrate. A passivation layer is over the FLIs, and a plurality of vias are through the passivation layer. A plurality of contacts are on the passivation layer in contact with the plurality vias to connect with the FLI. A plurality of topological crack stop (TCS) features are formed in the passivation layer and on a top surface of the etch stop layer to arrest a die passivation cracks.
Example embodiment 16: The integrated circuit structure of embodiment 15, wherein the TCS features comprise an inorganic dielectric material.
Example embodiment 17: The integrated circuit structure of embodiment 15 or 16, wherein the TCS features comprise an organic dielectric material.
Example embodiment 18: The integrated circuit structure of embodiment 15, 16 or 17, wherein the TCS features comprise metal or a combination of metals.
Example embodiment 19: A method of fabricating topological crack stop (TCS) features on a structure comprising a first level interconnects embedded in an underfill over a substrate, and an etch stop layer over the first layer interconnect. The method comprises forming a TCS layer over the etch stop layer. A TSC layer pattern is formed on the TCS layer. Trenches are etched in the TCS layer within openings in the TSA layer pattern to form the TCS features. A passivation layer is patterned and deposited over the TCS layer and via trenches are etched in the passivation layer. Via metallization is performed in the via trenches to form vias and contact metallization performed over the vias to form contact.
Example embodiment 20: The method of embodiment 19, further comprising using a nitride as the TCS layer, and forming the TCS layer to a thickness of approximately 2 µm and forming the trenches in the TCS layer to a thickness of approximately 1.5 µm.