BACKGROUND OF THE INVENTION

1. Field of the Invention

This application relates to the general field of Integrated Circuit (IC) devices and fabrication methods, and more particularly to multilayer or Three Dimensional Integrated Circuit (3D-IC) devices and fabrication methods.

2. Discussion of Background Art

Over the past 40 years, there has been a dramatic increase in functionality and performance of Integrated Circuits (ICs). This has largely been due to the phenomenon of “scaling”; i.e., component sizes within ICs have been reduced (“scaled”) with every successive generation of technology. There are two main classes of components in Complementary Metal Oxide Semiconductor (CMOS) ICs, namely transistors and wires. With “scaling”, transistor performance and density typically improve and this has contributed to the previously-mentioned increases in IC performance and functionality. However, wires (interconnects) that connect together transistors degrade in performance with “scaling”. The situation today is that wires dominate the performance, functionality and power consumption of ICs.

3D stacking of semiconductor devices or chips is one avenue to tackle the wire issues. By arranging transistors in 3 dimensions instead of 2 dimensions (as was the case in the 1990s), the transistors in ICs can be placed closer to each other. This reduces wire lengths and keeps wiring delay low.

There are many techniques to construct 3D stacked integrated circuits or chips including:Monolithic 3D technology: With this approach, multiple layers of transistors and wires can be monolithically constructed. Some monolithic 3D and 3DIC approaches are described in U.S. Pat. Nos. 8,273,610, 8,298,875, 8,362,482, 8,378,715, 8,379,458, 8,450,804, 8,557,632, 8,574,929, 8,581,349, 8,642,416, 8,669,778, 8,674,470, 8,687,399, 8,742,476, 8,803,206, 8,836,073, 8,902,663, 8,994,404, 9,023,688, 9,029,173, 9,030,858, 9,117,749, 9,142,553, 9,219,005, 9,385,058, 9,406,670, 9,460,978, 9,509,313, 9,640,531, 9,691,760, 9,711,407, 9,721,927, 9,799,761, 9,871,034, 9,953,870, 9,953,994, 10,014,292, 10,014,318, 10,515,981, 10,892,016; and pending U.S. Patent Application Publications and applications, Ser. Nos. 14/642,724, 15/150,395, 15/173,686, 16/337,665, 16/558,304, 16/649,660, 16/836,659, 17/151,867, 62/651,722; 62/681,249, 62/713,345, 62/770,751, 62/952,222, 62/824,288, 63/075,067, 63/091,307, 63/115,000, 63/220,443, 2021/0242189, 2020/0013791, 16/558,304; and PCT Applications (and Publications): PCT/US2010/052093, PCT/US2011/042071 (WO2012/015550), PCT/US2016/52726 (WO2017053329), PCT/US2017/052359 (WO2018/071143), PCT/US2018/016759 (WO2018144957), PCT/US2018/52332 (WO 2019/060798), and PCT/US2021/44110. The entire contents of all of the foregoing patents, publications, and applications are incorporated herein by reference.Electro-Optics: There is also work done for integrated monolithic 3D including layers of different crystals, such as U.S. Pat. Nos. 8,283,215, 8,163,581, 8,753,913, 8,823,122, 9,197,804, 9,419,031, 9,941,319, 10,679,977, 10,943,934, 10,998,374, 11,063,071, and 11,133,344. The entire contents of the foregoing patents, publications, and applications are incorporated herein by reference.

An early work on monolithic 3D was presented in U.S. Pat. No. 7,052,941 and follow-on work in related patents includes U.S. Pat. No. 7,470,598. A technique which has been used over the last 20 years to build SOI wafers, called “Smart-Cut” or “Ion-Cut”, was presented in U.S. Pat. No. 7,470,598 as one of the options to perform layer transfer for the formation of a monolithic 3D device. Yet in a related patent disclosure, by the same inventor of 7,470,598, U.S. application Ser. No. 12/618,542 it states: “In one embodiment of the previous art, exfoliating implant method in which ion-implanting Hydrogen into the wafer surface is known. But this exfoliating implant method can destroy lattice structure of the doped layer400by heavy ion-implanting In this case, to recover the destroyed lattice structure, a long time thermal treatment in very high temperature is required. This long time/high temperature thermal treatment can severely deform the cell devices of the lower region.” Moreover, in U.S. application Ser. No. 12/635,496 by the same inventor is stated: [0034] Among the technologies to form the detaching layer, one of the well-known technologies is Hydrogen Exfoliating Implant. This method has a critical disadvantage which can destroy lattice structures of the substrate because it uses high amount of ion implantation. In order to recover the destroyed lattice structures, the substrate should be cured by heat treatment in very high temperature long time. This kind of high temperature heat treatment can damage cell devices in the lower regions.” Furthermore, in U.S. application Ser. No. 13/175,652 it is stated: “Among the technologies to form the detaching layer207, one technology is called as exfoliating implant in which gas phase ions such as hydrogen is implanted to form the detaching layer, but in this technology, the crystal lattice structure of the multiple doped layers201,203,205can be damaged. In order to recover the crystal lattice damage, a thermal treatment under very high temperature and longtime should be performed, and this can strongly damage the cell devices underneath.” In fact the Inventor had posted a video infomercial on his corporate website, and was up-loaded on YouTube on Jun. 1, 2011, clearly stating in reference to the Smart Cut process: “The wafer bonding and detaching method is well-known SOI or Semiconductor-On-Insulator technology. Compared to conventional bulk semiconductor substrates, SOI has been introduced to increase transistor performance. However, it is not designed for 3D IC either. Let me explain the reasons . . . . The dose of hydrogen is too high and, therefore, semiconductor crystalline lattices are demolished by the hydrogen ion bombardment during the hydrogen ion implantation Therefore, typically annealing at more than 1,100 Celsius is required for curing the lattice damage after wafer detaching. Such high temperature processing certainly destroys underlying devices and interconnect layers. Without high temperature annealing, the transferred layer should be the same as a highly defective amorphous layer. It seems that there is no way to cure the lattice damage at low temperatures. BeSang has disruptive 3D layer formation technology and it enables formation of defect-free single crystalline semiconductor layer at low temperatures . . . .”

In at least one embodiment presented herein, an innovative method to repair the crystal lattice damage caused by the hydrogen implant is described.

Regardless of the technique used to construct 3D stacked integrated circuits or chips, heat removal is a serious issue for this technology. For example, when a layer of circuits with power density P is stacked atop another layer with power density P, the net power density is 2P. Removing the heat produced due to this power density is a significant challenge. In addition, many heat producing regions in 3D stacked integrated circuits or chips have a high thermal resistance to the heat sink, and this makes heat removal even more difficult.

Several solutions have been proposed to tackle this issue of heat removal in 3D stacked integrated circuits and chips. These are described in the following paragraphs.

Publications have suggested passing liquid coolant through multiple device layers of a 3D-IC to remove heat. This is described in “Microchannel Cooled 3D Integrated Systems”, Proc. Intl. Interconnect Technology Conference, 2008 by D. C. Sekar, et al., and “Forced Convective Interlayer Cooling in Vertically Integrated Packages,” Proc. Intersoc. Conference on Thermal Management (ITHERM), 2008 by T. Brunschweiler, et al.

Thermal vias have been suggested as techniques to transfer heat from stacked device layers to the heat sink. Use of power and ground vias for thermal conduction in 3D-ICs has also been suggested. These techniques are described in “Allocating Power Ground Vias in 3D ICs for Simultaneous Power and Thermal Integrity” ACM Transactions on Design Automation of Electronic Systems (TODAES), May 2009 by Hao Yu, Joanna Ho and Lei He.

Other techniques to remove heat from 3D Integrated Circuits and Chips will be beneficial.

Additionally the 3D technology according to some embodiments of the invention may enable some very innovative IC alternatives with reduced development costs, increased yield, and other illustrative benefits.

SUMMARY

The invention may be directed to multilayer or Three Dimensional Integrated Circuit (3D IC) devices and fabrication methods.

In one aspect, a semiconductor device, the device including: a first silicon layer including a first single crystal silicon; a first metal layer over the first silicon layer; a second metal layer over the first metal layer; a first level including a plurality of transistors over the second metal layer, where the plurality of transistors include a second single crystal silicon; a third metal layer over the first level; a fourth metal layer over the third metal layer, where the fourth metal layer is aligned to the first metal layer with less than 40 nm alignment error; and a via disposed through the first level, where the via has a diameter of less than 450 nm.

In another aspect, a semiconductor device, the device including: a first silicon layer including first single crystal silicon; a first metal layer over the first silicon layer; a second metal layer over the first metal layer; a first level including a plurality of transistors over the second metal layer, where the plurality of transistors include second single crystal silicon; a third metal layer over the first level; a fourth metal layer over the third metal layer, where the fourth metal layer is aligned to the first metal layer with less than 40 nm alignment error; and a via disposed through the first level, where the via includes tungsten.

In another aspect, a 3D semiconductor device, the device including: a first level overlaid by a second level, the first level including first circuits, where the first circuits include single crystal first transistors and include first interconnections, where the second level includes second circuits, the second circuits include single crystal second transistors and include second interconnections, where the first circuit is aligned to the second circuit with less than 200 nm misalignment; and a Global Power distribution network, where the first level includes at least one Local Power distribution network, where the Global Power distribution network distributes power to the Local Power distribution network, where the Global Power distribution network includes wires including an at least 50% greater conductivity than wires of the Local Power distribution network.

In another aspect, a semiconductor device, the device including: a first silicon layer including single crystal silicon; a first metal layer over the first silicon layer; second metal layer over the first metal layer; a first level including a plurality of transistors over the second metal layer, where the plurality of transistors include single crystal silicon; a third metal layer over the first level; a fourth metal layer over the third metal layer, where the fourth metal layer is aligned to the first metal layer with less than 40 nm alignment error; a global power distribution network and a local power distribution network, where the global power distribution network includes the fourth metal layer, and where the local power distribution network includes the third metal layer.

In another aspect, a method to form a 3D semiconductor device, the method including: providing a first level including first circuits, the first circuits including first transistors and first interconnection; preparing a second level including a silicon layer; forming second circuits over the second level, the second circuits including second transistors and second interconnection; transferring with bonding the second level on top of the first level; and then thinning the second level to a thickness of less than ten microns, where the device includes an upper most semiconductor level, where the upper most semiconductor level includes Input/Output (“I/O”) circuits designed to connect the device to external devices, and where the bonding is hybrid bonding.

In another aspect, a method to form a 3D semiconductor device, the method including: providing a first level including first circuits, the first circuits including first transistors and first interconnection; preparing a second level including a silicon layer; forming second circuits over the second level, the second circuits including second transistors and second interconnection; transferring with bonding the second level on top of the first level; and then thinning the second level to a thickness of less than ten microns; and forming heat removal paths designed to remove heat from the second circuits to an external surface of the 3D semiconductor device, where the bonding is hybrid bonding.

In another aspect, a method to form a 3D semiconductor device, the method including: providing a first level including first circuits, the first circuits including first transistors and first interconnection; preparing a second level including a silicon layer; forming second circuits over the second level, the second circuits including second transistors and second interconnection; transferring with bonding the second level on top of the first level; and then thinning the second level to a thickness of less than thirty microns, where the bonding includes oxide to oxide bonds, where the bonding includes metal to metal bonds, and where at least one of the metal to metal bond structures has a pitch of less than 1 micron from another of the metal to metal bond structures.

In another aspect, a method to form a 3D semiconductor device, the method including: providing a first level including first circuits, the first circuits including first transistors and first interconnection; preparing a second level including a silicon layer; forming second circuits over the second level, the second circuits including second transistors and second interconnection; transferring with bonding the second level on top of the first level; and then thinning the second level to a thickness of less than thirty microns, where the device includes an upper most semiconductor level, where the upper most semiconductor level includes Input/Output (“I/O”) circuits designed to connect the device to external devices, and where the bonding is hybrid bonding.

In another aspect, a method to form a 3D semiconductor device, the method including: providing a first level including first circuits, the first circuits including first transistors and first interconnection; preparing a second level including a silicon layer; forming second circuits over the second level, the second circuits including second transistors and second interconnection; transferring with bonding the second level on top of the first level; and then thinning the second level to a thickness of less than thirty microns; and forming heat removal paths designed to remove heat from the second circuits to an external surface of the 3D semiconductor device, where the bonding is hybrid bonding.

In another aspect, a semiconductor device, the device including: a first silicon layer including first single crystal silicon; a first metal layer disposed over the first silicon layer; a second metal layer disposed over the first metal layer; a first level including a plurality of transistors, the first level disposed over the second metal layer, where the plurality of transistors include second single crystal silicon; a third metal layer disposed over the first level; a fourth metal layer disposed over the third metal layer, where the fourth metal layer is aligned to the first metal layer with a less than 40 nm alignment error; a power distribution network, where the power distribution network includes the third metal layer, and a plurality of connection paths from the power distribution network to the plurality of transistors.

In another aspect, a semiconductor device, the device including: a first silicon layer including first single crystal silicon; a first metal layer disposed over the first silicon layer; a second metal layer disposed over the first metal layer; a first level including a plurality of transistors, the first level disposed over the second metal layer, where the plurality of transistors include second single crystal silicon; a third metal layer disposed over the first level; a fourth metal layer disposed over the third metal layer, where the fourth metal layer is aligned to the first metal layer with a less than 40 nm alignment error; a via disposed through the first level; and connection pads disposed over a portion of the fourth metal layer, where the connection pads are capable to include connection to external devices.

In another aspect, a semiconductor device, the device including: a first silicon layer including a first single crystal silicon; a first metal layer disposed over the first silicon layer; a second metal layer disposed over the first metal layer; a first level including a plurality of transistors, the first level disposed over the second metal layer, where the plurality of transistors include a second single crystal silicon; a third metal layer disposed over the first level; a fourth metal layer disposed over the third metal layer, where the fourth metal layer is aligned to the first metal layer with a less than 40 nm alignment error; and a via disposed through the first level, where the first level thickness is less than two microns.

In another aspect, a semiconductor device, the device including: a first silicon layer including a first single crystal silicon and plurality of first transistors; a first metal layer disposed over the first silicon layer; a second metal layer disposed over the first metal layer; a third metal layer disposed over the second metal layer, a second level including a plurality of second transistors, the first level disposed over the third metal layer; a fourth metal layer disposed over the second level; a fifth metal layer disposed over the fourth metal layer, where the fourth metal layer is aligned to the first metal layer with a less than 40 nm alignment error; and a via disposed through the second level, where the second level thickness is less than two microns, where the fifth metal layer includes a global power distribution grid, and where a typical thickness of the fifth metal layer is greater than the typical thickness of the second metal layer by at least 50%.

In another aspect, a semiconductor device, the device including: a first silicon layer including a first single crystal silicon and a plurality of first transistors; a first metal layer disposed over the first silicon layer; a second metal layer disposed over the first metal layer; a third metal layer disposed over the second metal layer, a second level including a plurality of second transistors, the first level disposed over the third metal layer; a fourth metal layer disposed over the second level; a fifth metal layer disposed over the fourth metal layer, where the fourth metal layer is aligned to the first metal layer with a less than 40 nm alignment error; and a via disposed through the second level, where the via has a diameter of less than 450 nm, where the fifth metal layer include global power distribution grid, and where a typical thickness of the fifth metal layer is greater than a typical thickness of the second metal layer by at least 50%.

In another aspect, a semiconductor device, the device including a first silicon layer including a first single crystal silicon and a plurality of first transistors; a first metal layer disposed over the first silicon layer; a second metal layer disposed over the first metal layer; a third metal layer disposed over the second metal layer; a second level including a plurality of second transistors, the first level disposed over the third metal layer, a fourth metal layer disposed over the second level; a fifth metal layer disposed over the fourth metal layer, where the fourth metal layer is aligned to the first metal layer with a less than 40 nm alignment error; and a via disposed through the second level, where the via has a diameter of less than 450 nm, where at least one of the plurality of second transistors includes a metal gate, where the fifth metal layer includes a global power distribution grid, and where a typical thickness of the fifth metal layer is greater than a typical thickness of the second metal layer by at least 50%.

In another aspect, a semiconductor device, the device including: a first silicon layer comprising a first single crystal silicon and a plurality of first transistors; a first metal layer disposed over the first silicon layer; a second metal layer disposed over the first metal layer; a third metal layer disposed over the second metal layer; a second level comprising a plurality of second transistors, the second level disposed over the third metal layer; a fourth metal layer disposed over the second level; a fifth metal layer disposed over the fourth metal layer, a connection path from the fifth metal layer to the second metal layer, where the connection path includes a via disposed through the second level, where the via has a diameter of less than 450 nm, where the fifth metal layer includes a global power distribution grid, and where a typical thickness of the fifth metal layer is greater than a typical thickness of the second metal layer by at least 50%.

In another aspect, a semiconductor device, the device including: a first silicon layer comprising a first single crystal silicon and a plurality of first transistors; a first metal layer disposed over the first silicon layer; a second metal layer disposed over the first metal layer; a third metal layer disposed over the second metal layer; a second level comprising a plurality of second transistors, the second level disposed over the third metal layer; a fourth metal layer disposed over the second level; a fifth metal layer disposed over the fourth metal layer; a connection path from the fifth metal layer to the second metal layer, where the connection path includes a via disposed through the second level, where the via has a diameter of less than 450 nm, where a typical thickness of the second metal layer is greater than a typical thickness of the third metal layer by at least 50%, where the fifth metal layer includes a global power distribution grid, and where a typical thickness of the fifth metal layer is greater than a typical thickness of the second metal layer by at least 50%.

In another aspect, a semiconductor device, the device including: a first silicon layer comprising a first single crystal silicon and a plurality of first transistors; a first metal layer disposed over the first silicon layer; a second metal layer disposed over the first metal layer; a third metal layer disposed over the second metal layer; a second level comprising a plurality of second transistors, the second level disposed over the third metal layer; a fourth metal layer disposed over the second level; a fifth metal layer disposed over the fourth metal layer; a connection path from the fifth metal layer to the second metal layer, where the connection path includes a via disposed through the second level, where the via has a diameter of less than 450 nm, where the second level includes an array of memory cells, where each of the memory cells includes at least one of the plurality of second transistors, where the fifth metal layer includes a global power distribution grid, and where a typical thickness of the fifth metal layer is greater than a typical thickness of the second metal layer by at least 50%.

