This relates generally to integrated circuit packages, and more particularly, to integrated circuit packages with embedded multi-die interconnect bridges (EMIBs) that connect more than one integrated circuit die.
An integrated circuit package typically includes an integrated circuit die and a substrate on which the die is mounted. The die can be coupled to the substrate through bonding wires or solder bumps. Signals from the integrated circuit die may then travel through the bonding wires or solder bumps to the substrate.
As demands on integrated circuit technology continue to outstrip even the gains afforded by ever decreasing device dimensions, more and more applications demand a packaged solution with more integration than possible in one silicon die. In an effort to meet this need, more than one die may be placed within a single integrated circuit package (i.e., a multichip package). As different types of devices cater to different types of applications, more dies may be required in some systems to meet the requirements of high performance applications. Accordingly, to obtain better performance and higher density, an integrated circuit package may include multiple dies arranged laterally along the same plane.
EMIBs are small silicon dies that are sometimes embedded in the substrate of a multichip package and are used to interconnect integrated circuit dies within that multichip package. Traditionally, these EMIBS have limited power delivery capability compared to other interposer technologies such as silicon interposers.
It is within this context that the embodiments described herein arise.
An integrated circuit package may include a package substrate and one or more integrated circuit dies mounted on the package substrate. The package substrate may include an embedded multi-die interconnect bridge (EMIB) embedded within the package substrate. An EMIB is a silicon die that may be used to interconnect two integrated circuits in a multi-chip package. The integrated circuit dies mounted on the package substrate may communicate with one another through the EMIB. The EMIB may have a front side that faces the integrated circuit dies and a back side that opposes the front side. The package substrate may include a conductive path that is electrically coupled to the EMIB from the back side of the EMIB and that supplies power to the EMIB. The package substrate may be mounted on a printed circuit board that provides power to the EMIB through the conductive path.
The package substrate may also include a conductive layer (e.g., back side conductor) on which the EMIB is mounted. The conductive path may be connected to the conductive layer and may provide power to the EMIB through the conductive layer. A patterned adhesive layer may be applied to the conductive layer before the EMIB is mounted on the conductive layer and may include openings that accommodate conductive pads (e.g., contact pads) formed at the back side of the EMIB. In other words, once the EMIB is mounted on the conductive layer, the patterned adhesive layer may laterally surround the conductive pads formed at the back side of the EMIB. Additional contact pads may be formed at the front side of the EMIB.
The package substrate may include a first via directly connected to a contact pad formed at the front side of the EMIB, and may include a second via that is coupled to a contact pad formed at the back side of the EMIB through the conductive layer. The second via may have a diameter that is greater than a diameter of the first via.
The EMIB may include a conductive routing trace (e.g., interconnect) that is coupled to the integrated circuit dies. A microvia formed in the EMIB may be coupled between one of the conductive pads formed at the back side of the EMIB and the conductive routing trace. Power supply voltage signals or data signals may be provided to the conductive routing trace through the microvia.
The EMIB may include multiple through-silicon vias that extend from the back side of the EMIB to the front side of the EMIB. These through-silicon vias may be used to transfer power or data signals from the conductive path to the integrated circuit dies through the EMIB.
The conductive layer may include multiple conductive regions that are electrically isolated from one another. Each region of the conductive layer may receive a different power supply voltage signal or data signal from each other region of the conductive layer.
Fabricating an integrated circuit package may include multiple processing steps. A first dielectric layer may be formed. A via may be formed through the first dielectric layer. A conductive layer may be formed on the first dielectric layer in direct physical contact with the via. Forming the conductive layer may involve forming multiple conductive regions that are electrically isolated from one another. A silicon die (e.g., an EMIB) may be mounted on the conductive layer. Additional dielectric layers may be formed covering the silicon die. A first integrated circuit die may be mounted on the additional dielectric layers. A second integrated circuit die may be mounted on the additional dielectric layers. The silicon die may include a conductive routing trace that couples the first integrated circuit die to the second integrated circuit die.
Before forming the additional dielectric layer, a second dielectric layer may be formed on the first dielectric layer. A cavity may be formed in the second dielectric layer directly over the conductive layer. Mounting the silicon die on the conductive layer may include inserting the silicon die into the cavity. A patterned adhesive layer may be formed between the silicon die and the conductive layer. The patterned adhesive die may include a plurality of openings to accommodate contact pads formed on a bottom surface of the silicone die.
Further features of the present invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description.
Embodiments of the present invention relate to integrated circuits, and more particularly, to ways of improving power delivery through an embedded multi-die interconnect bridge in a multichip package.
As integrated circuit fabrication technology scales towards smaller process nodes, it becomes increasingly challenging to design an entire system on a single integrated circuit die (sometimes referred to as a system-on-chip). Designing analog and digital circuitry to support desired performance levels while minimizing leakage and power consumption can be extremely time consuming and costly.
One alternative to single-die packages is an arrangement in which multiple dies are placed within a single package. Such types of packages that contain multiple interconnected dies may sometimes be referred to as systems-in-package (SiPs), multi-chip modules (MCM), or multichip packages. Placing multiple chips (dies) into a single package may allow each die to be implemented using the most appropriate technology process (e.g., a memory chip may be implemented using the 28 nm technology node, whereas the radio-frequency analog chip may be implemented using the 45 nm technology node), may increase the performance of die-to-die interface (e.g., driving signals from one die to another within a single package is substantially easier than driving signals from one package to another, thereby reducing power consumption of associated input-output buffers), may free up input-output pins (e.g., input-output pins associated with die-to-die connections are much smaller than pins associated with package-to-board connections), and may help simplify printed circuit board (PCB) design (i.e., the design of the PCB on which the multi-chip package is mounted during normal system operation).
In order to facilitate communications between two chips on a multi-chip package, the package may include an embedded multi-die interconnect bridge (EMIB) that is designed and patented by INTEL Corporation. An EMIB is a small silicon die that is embedded in the underlying substrate of a multi-chip package and that offers dedicated ultra-high-density interconnection between dies within the package. EMIBs generally include wires of minimal length, which help to significantly reduce loading and directly boost performance.
EMIB solutions may be advantageous over other multi-chip packaging schemes that use a silicon interposer, which is prone to issues such as warpage and requires a comparatively large number of microbumps and through-silicon vias (TSVs) to be formed on and within the interposer, thereby reducing overall yield and increasing manufacturing complexity and cost. The number of dies that can be integrated using an interposer is also limited to that supported by EMIB technology.
The EMIB technology described above may be used as an interface between one or more integrated circuit dies in a system.
The electronic devices may be any suitable type of electronic device that communicates with other electronic devices. Examples of such electronic devices include basic electronic components and circuits such as analog circuits, digital circuits, mixed-signal circuits, circuits formed within a single package, circuits housed within different packages, circuits that are interconnected on a printed-circuit board (PCB), etc.
As shown in
An EMIB may be embedded in a multi-chip package to connect two adjacent integrated circuit dies on the package. As shown in
Main die 202 may be coupled to a secondary die 205 using EMIB 320 that is embedded in package substrate 300. Signals being passed between main die 202 and secondary die 205 may pass through interconnects (e.g., conductive paths) 322 and microbumps 305. EMIB 320 may have a front side that faces main die 202 and secondary die 205 and may have a back side that faces package substrate 300. An EMIB is traditionally formed on a solid, electrically floating conductive plate for structural support. It is therefore difficult to provide power to microbumps 305 that overlap with regions 203 and 207 of main die 202 and secondary die 205, as power cannot be delivered vertically from the PCB through the EMIB to regions 203 and 207 because back side routing is blocked by the conductive plate.
These power supply and common voltage signals may be delivered to peripheral microbumps in regions 203 and 207 without exceptional loss in power efficiency. For example, voltage signals Vss, Vcc1, and Vcc2 may be delivered to the microbumps at the edges of the microbump arrays of regions 203 and 207 using conductors (e.g., copper traces) formed in a top layer of the package substrate.
Additionally, microbumps in the center (e.g., not at the periphery) of the microbump arrays of regions 203 and 207 may have voltage signals Vss, Vcc1, and Vcc2 routed to them by forming conductors (e.g., copper traces) in a top layer of the package substrate arranged to extend vertically across a given microbump array. Only microbumps in the path of one of these conductors may receive respective voltage signal carried by that conductor. However, extending one of these conductors to cover the entire width of a microbump array may undesirably result in a loss in power efficiency. It would therefore be advantageous to provide alternate means of power delivery for microbumps in the center of the microbump arrays of regions 203 and 207.
One alternative to the topside microbump power delivery described above is to deliver power and ground signals to the microbumps from the PCB vertically through the package substrate and the EMIB from the back side. As shown in
Solder bumps 304 may be provided with signals (e.g., data signals or power supply voltage signals) from a printed circuit board (e.g., PCB 350 of
Microbumps 305 may be provided with signals (e.g., data signals or power supply voltage signals) from EMIB 320 through vias 505 and traces 503. The signals provided to microbumps 305 may be received from another chip coupled to EMIB 302 or from a PCB (e.g., PCB 350 of
EMIB 320 may be mounted on a back side conductor (e.g., conductive layer or copper conductive layer) 510 in layer 351-2 of package substrate 300 using an adhesive layer 514 during fabrication of package substrate 300. A cavity 512 may be included adjacent to EMIB 320 in order to account for differences between the coefficient of thermal expansion between EMIB 320 and package substrate 300, which may reduce thermal stresses placed on EMIB 320.
EMIB 320 may include through-silicon vias (TSVs) that extend vertically from the front side of EMIB 320 to the back side of EMIB 320 to connect contact pads 516 formed on the front side of EMIB 320 to contact pads 518 formed on the back side of EMIB 320. Adhesive layer 514 may be patterned to accommodate contact pads 518 to ensure that contact pads 518 are in electrical contact with back side conductor 510. In other words, adhesive layer 514 may laterally surround contact pads 518 of EMIB 320 without being interposed between contact pads 518 and back side conductor 510.
In accordance with an embodiment, back side conductor 510 may receive power supply voltage signals and/or data signals from a PCB (e.g., PCB 350 of
By providing signals to EMIB 320 from the PCB through back side conductor 510, vias 504′, and traces 502′, and providing power to one or both circuit dies through TSVs 520 in EMIB 320, vertical power distribution may be achieved through EMIB 320.
Conventional EMIB arrangements lack such back side vertical power distribution paths and instead are limited to passing power between chips connected by the EMIB over the EMIB itself or by routing power to these chips around the EMIB. Both of these conventional power distribution options disadvantageously reduce power efficiency of the system containing the EMIB by requiring smaller gauge traces or longer traces for power delivery compared to the vertical power distribution path coupled to EMIB 320.
Thus, the vertical power distribution path coupled between the PCB and the back side of EMIB 320 that includes back side conductor 510, vias 504′, and traces 502′ is advantageous over these conventional EMIB arrangements in terms of power efficiency.
Signals may also be provided from the PCB to internal interconnects of EMIB 320. As shown in
Microvia 608 may only extend from contact pad 518-2 to interconnect 604. Contact pad 518-2 may pass received signals to interconnect 604 through microvia 608. Optionally, an additional microvia 608′ may be interposed between interconnect 602 and interconnect 604 and/or may be interposed between contact pad 516-2 and interconnect 602. This arrangement allows for signals received by contact pad 518-2 to be passed to each of interconnects 602 and 604 and to contact pad 516-2 and thereby to any microbumps coupled to contact pad 516-2.
If desired, back side conductor 510 of
As shown in
As shown in
As shown in
The arrangements of back side conductor 510 shown in
At step 800, first dielectric layer 351-1 may be formed. Vias 504 and 504′ in layer 351-1 and traces 502 and 502′ may also be formed at this step.
At step 802, second dielectric layer 351-2 may be formed. Via 504, trace 502, and back side conductor 510 may also be formed in layer 351-2 at this step. As described in connection with
At step 804, third dielectric layer 351-3 may be formed. Via 504 and trace 502 may be formed in layer 351-3 at this step.
At step 806, a cavity may be formed in second dielectric layer 351-2 and third dielectric layer 351-3 (e.g., using photolithographic etching, lapping, or drilling). The cavity may overlap back side conductor 510 and may extend through layers 351-2 and 351-3 so as to expose back side conductor 510.
At step 808, adhesive layer 514 may be patterned within the cavity, such that openings are formed in adhesive layer 514 to accommodate contact pads 518 of EMIB 320.
At step 810, EMIB 320 may be placed on the patterned adhesive within the cavity, and may thereby be mounted on back side conductor 510. It should be noted that any TSVs or internal EMIB microvias may already be formed within EMIB 320 prior to the placement of EMIB 320 in the cavity (e.g., during fabrication of EMIB 320).
At step 812, remaining dielectric layers including dielectric layer 851-4 and the portion of dielectric layer 851-3 disposed over EMIB 320 may be formed. Vias 504 and 505 and traces (e.g., via pads) 502 and 503 may also be formed at this step.
Optionally, step 804 may be omitted and the entirety of layer 851-3 may be formed during step 812. In this optional case, the cavity only needs to be formed in second dielectric layer 851-2 during step 806.
The embodiments thus far have been described with respect to integrated circuits. The methods and apparatuses described herein may be incorporated into any suitable circuit. For example, they may be incorporated into numerous types of devices such as programmable logic devices, application specific standard products (ASSPs), and application specific integrated circuits (ASICs). Examples of programmable logic devices include programmable arrays logic (PALs), programmable logic arrays (PLAs), field programmable logic arrays (FPLAs), electrically programmable logic devices (EPLDs), electrically erasable programmable logic devices (EEPLDs), logic cell arrays (LCAs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs), just to name a few.
The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art. The foregoing embodiments may be implemented individually or in any combination.
This application is a continuation of U.S. patent application Ser. No. 17/716,928, filed Apr. 8, 2022, which is a continuation of U.S. patent application Ser. No. 17/581,751, filed Jan. 21, 2022, which is a continuation of U.S. patent application Ser. No. 15/439,118, filed on Feb. 22, 2017, the entire contents of which are hereby incorporated by reference herein.
Number | Date | Country | |
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Parent | 17716928 | Apr 2022 | US |
Child | 18128964 | US | |
Parent | 17581751 | Jan 2022 | US |
Child | 17716928 | US | |
Parent | 15439118 | Feb 2017 | US |
Child | 17581751 | US |