Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W42/00—Arrangements for protection of devices
  • H10W42/40—Arrangements for protection of devices protecting against tampering, e.g. unauthorised inspection or reverse engineering
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W42/00—Arrangements for protection of devices
  • H10W42/40—Arrangements for protection of devices protecting against tampering, e.g. unauthorised inspection or reverse engineering
  • H10W42/405—Arrangements for protection of devices protecting against tampering, e.g. unauthorised inspection or reverse engineering using active circuits
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/90—Bond pads, in general
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/90—Bond pads, in general
  • H10W72/931—Shapes of bond pads
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W80/00—Direct bonding of chips, wafers or substrates
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W90/00—Package configurations
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W99/00—Subject matter not provided for in other groups of this subclass
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/90—Bond pads, in general
  • H10W72/921—Structures or relative sizes of bond pads
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/90—Bond pads, in general
  • H10W72/951—Materials of bond pads
  • H10W72/952—Materials of bond pads comprising metals or metalloids, e.g. PbSn, Ag or Cu
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W90/00—Package configurations
  • H10W90/701—Package configurations characterised by the relative positions of pads or connectors relative to package parts
  • H10W90/791—Package configurations characterised by the relative positions of pads or connectors relative to package parts of direct-bonded pads
  • H10W90/792—Package configurations characterised by the relative positions of pads or connectors relative to package parts of direct-bonded pads between multiple chips

Definitions

• the field relates to bonded structures comprising active and/or protective semiconductor elements and methods for forming the same.
• Semiconductor chips may include active circuitry containing security- sensitive components which contain valuable and/or proprietary information, structures or devices.
• security-sensitive components may include an entity’s intellectual property, software or hardware security (e.g., encryption) features, privacy data, or any other components or data that the entity may wish to remain secure and hidden from third parties.
• entity intellectual property
• software or hardware security e.g., encryption
• third party bad actors may utilize various techniques to attempt to access security- sensitive components for economic and/or geopolitical advantage. Accordingly, there remains a continuing need for improving the security of semiconductor chips from being accessed by third parties.
• Figure 1 is an example illustration of optical imaging of a semiconductor chip.
• Figure 2 is an example illustration of a focused ion beam (FIB) attack of a semiconductor chip.
• FIB focused ion beam
• Figure 3 is a schematic side sectional view showing an example solution to invasive chip attacks.
• Figure 4A is a schematic side sectional view showing an example illustration of a protective chip incorporating a protective layer.
• Figure 4B is a schematic side sectional view showing an example illustration of a protective chip incorporating a protective layer in conjunction with an obstructive layer.
• the third party may attempt to hack the security- sensitive components by pulsing electromagnetic (EM) waves onto active circuitry of the element, using fault injection techniques, employing near infrared (NIR) laser triggering or focused ion beam (FIB) modification of circuits, chemical etching techniques, and other physical, chemical, and/or electromagnetic hacking tools and even reverse engineering.
• NIR near infrared
• FIB focused ion beam
• These techniques can be used to physically access sensitive circuits of microdevices such as integrated circuits to directly read encrypted information, to trigger circuits to release information otherwise encrypted, to understand manufacturing processes, to extract enough information to be able to eventually replicate sensitive designs, or to completely bypass the security protocols to activate or use the chip without due permissions.
• Semiconductor chips face both hardware- and software-level attacks. In some cases, these can be combined in a single technique. For example, a hardware attack on a chip may be utilized to alter the logic of a software program by providing faulty data or affecting the logic circuits used to process data.
• the active circuitry 116 can be closer to the front side 114 of the semiconductor element than to the back side 112 of the element 100.
• the active circuitry 116 can be patterned at or near the front side 114 of the element 100.
• the optical probe 126 includes a laser source 122, a beam splitter 120, a detector 124, and an objective lens 118.
• the laser source 122 can create and direct a laser beam to the beam splitter 120, which can split the beam into a first component that is directed through the objective lens 118 to the semiconductor element 100 and a second component that is directed to a mirror 128 and the detector 124.
• Preventing optical intrusion is thus important to ensuring the security of semiconductor chips containing security-sensitive components.
• Conventional techniques may include packaging semiconductor elements with protective casings.
• conventional packaging may be susceptible to grinding, chemical etching, and other package decapping processes that are relatively unsophisticated, leaving the sensitive circuitry exposed and susceptible to optical probing. It may thus be desirable to include protection against optical intrusions by bonding one or more protective elements directly to a semiconductor element, e.g., an active chip having active circuitry 116 including sensitive circuitry.
• Semiconductor elements 100 such as integrated device dies or chips, may be mounted or stacked on other elements.
• a semiconductor element 100 can be mounted to a carrier, such as a package substrate, an interposer, a reconstituted wafer or element, etc.
• a semiconductor element 100 can be stacked on top of another semiconductor element 100, e.g., a first integrated device die can be stacked on a second integrated device die.
• a through-substrate via (TSV) can extend vertically through a thickness of the semiconductor element 100 to transfer electrical signals through the semiconductor element 100, e.g., from a first surface of the semiconductor element 100 to a second opposing surface of the semiconductor element 100.
• the FIB may be used to alter the function of active chips, by inducing current flows, severing or altering traces that connect elements of the sensitive circuit. This may allow an attacker to modify and/or bypass protective structures within the sensitive semiconductor layer. Further, an FIB or laser probe may be used subsequent to ablation to capture bitstream information or image sensitive circuit elements.
• hackers may access and directly monitor security critical nets of an IC and extract sensitive information. Attacks such as these typically happen on the front side of the chip but may also occur on the backside.
• FIG. 3 shows an illustrative example of protective measures employed to thwart imaging attacks of sensitive semiconductor chips.
• an active chip 310 may be bonded (e.g., directly bonded without an adhesive) to a protective chip 300 containing an obstructive layer 305.
• the protective chip 300 can be directly bonded to a back side 112 of the active chip 310 that is opposite the front side 114 (which can comprise an active side nearer to the active circuitry 116 than the back side 112).
• the obstructive layer 305 may be an optically-occlusive layer designed to prevent laser probing, FIB or other hacking techniques of the active circuit layer 116 of the active chip 310, such as described in U.S.
• Patent Application No. 17/812,675 filed July 14, 2022, the entire contents of which are hereby incorporated. As shown in Figure 2 above, this provides limited protection against FIB attacks.
• a motivated attacker may, for example, identify a target region 204 of the active chip 310 and employ an FIB attack to remove the portions of the obstructive layer 305 covering the target area 204 of the chip 310, leaving it exposed to probing.
• the obstructive layer 305 can comprise several layers, such as a plurality of metallized layers (e.g. 342A,B) spaced apart by an insulating material 343.
• the metallized layers 342A,B and intervening insulating material 343 form a capacitive circuit with positive and negative terminals respectively connected to the two illustrated through-substrate vias (TSVs) 330.
• TSVs through-substrate vias
• a bond interface 315 may comprise a bond between a bonding layer 340A of the protective chip 300 and a bonding layer 340B of the active chip 310.
• the direct bond may comprise a nonconductive non-adhesive bond in which nonconductive layer 341 A, 34 IB (e.g., dielectric materials) of the bonding layer 340A,B are directly bonded to one another.
• the protective chip 300 is bonded to the backside 312 of the active chip 310.
• the obstructive layer 305 is located near the bonding layer 340A of the protective chip 310.
• the direct bond may comprise a hybrid bond in which conductive contact features 350B of the active chip 310 are directly bonded to corresponding conductive contact features 350A of the protective chip 300, and in which nonconductive regions (e.g., nonconductive layer 34 IB) of the active chip 310 are directly bonded to corresponding nonconductive regions (e.g., a nonconductive layer 341 A) of the protective chip 300.
• the bonding layer 340A, 340B of each chip 300, 310 may comprise a plurality of conductive contact features 350A, B disposed in a nonconductive layers 341 A, 34 IB, such as a dielectric layer (e.g., silicon oxide, silicon nitride, silicon oxynitrocarbide, etc.)
• the conductive contact features 350A, B may comprise conductive material, e.g., a metal such as copper prepare for direct hybrid bonding.
• the conductive contact features 350A of the protective chip 300 may be configured to mirror and/or correspond to the conductive contact features 350B of the active chip 310.
• the pads may provide an electrical and/or mechanical connection between the protective and active chips.
• the pads can comprise exposed ends of through substrate vias (TSVs) 330 or vertical interconnects 330 (e.g., labeled as pad 350A) or discrete pads at least partially embedded in the field region (e.g., labeled as pad 350B).
• TSVs through substrate vias
• pad 350A vertical interconnects 330
• pad 350B discrete pads at least partially embedded in the field region
• an active chip 310 may be configured to detect alteration of a protective chip 300.
• a protective chip 300 may be electrically connected to the active circuitry 116 of an active chip 310 by through-substrate vias (TSVs) 330 that may enable the active chip 310 to sense changes to the properties of the protective chip 300 caused by removal of material from the obstructive layer 305.
• TSVs through-substrate vias
• the protective chip 300 may be electrically connected to the active chip 310 through a direct hybrid bond or other interconnect technology.
• the active chip 310 may be configured to measure the resistance or the capacitance of the obstructive layer 305 or other structures built within the protective chip.
• Embodiments of the present disclosure are directed at bonded structures including protective chips 300 comprising protective layers resistant to invasive attacks bonded directly to active chips 310 that may comprise securitysensitive circuitry or circuit elements.
• Figure 4A illustrates an example embodiment of the present disclosure directed at remedying the shortcomings of other solutions to protecting sensitive semiconductor chips 100 from sophisticated intrusions employing optical and/or invasive FIB attacks.
• embodiments of the present disclosure may include a protective chip 300 comprising a protective circuitry layer 410, the protective chip 300 directly bonded to the active chip 310 (e.g., to the back side 112 of the chip 310).
• the protective circuitry layer 410 can be configured to detect or disrupt external access to the protective element and/or the active circuitry of the semiconductor element.
• the disclosed embodiments can include an obstructive layer 305 and a separate protective circuitry layer 410, formed in the protective chip 300 which can be directly bonded to an active chip 310 (e.g. , the back side 112 of the chip 310) to protect an active circuitry 116 of the active chip 310.
• the active circuitry 116 is located near the front side 114 of the active chip 310 in the illustrated embodiment.
• non-bonded protective structures may be susceptible to removal via relatively easy removal techniques, such as grinding or etching. It may therefore be desirable to incorporate a protective chip 300 and active chip 310 into a bonded structure.
• a bond interface 315 may comprise a bond between a bonding layer 340 A of the protective chip 300 and a bonding layer 340B of the active chip 310, which in the illustrated embodiments may be formed at or at least partially define the back side 112 of the chip 310.
• the direct bond may comprise a nonconductive non-adhesive bond in which nonconductive material(s) (e.g., dielectric and/or semiconductor materials 341A,B) of the elements are directly bonded to one another.
• the direct bond may comprise a hybrid bond in which conductive contact features or pads 350A of the active chip 310 are also directly bonded to corresponding conductive contact features 350B of the protective chip 300, and in which nonconductive regions (e.g., a bonding layer 340B) of the active chip 310 are directly bonded to corresponding nonconductive regions (e.g., a bonding layer 340A) of the protective chip 300.
• the bonding layer 315 of each chip may comprise a plurality of contact pads 350 disposed in a nonconductive material, such as a nonconductive or dielectric layer 341 (e.g., silicon oxide, silicon nitride, silicon oxynitrocarbide, etc.).
• the contact pads 350 may comprise conductive material, e.g., a metal such as copper.
• the contact pads 350 of the protective chip 300 may be configured to mirror and/or correspond to the contact pads 350 of the active chip 310.
• the pads 350 may provide an electrical and/or mechanical connection between the protective 300 and active chips 310.
• the contact pads 350 of the bonding layer 315 of the active chip 350 may be connected to the active circuitry 116 of the active chip 310 through TSVs 330.
• the bonded structure may thus have an electrical connection between the active circuitry 116 of the active chip 310 and one or more layers of the protective chip 300.
• a protective chip 300 may have vertical connectors (e.g. vertical interconnects) 360 providing electrical connections between the protective circuitry layer 410 and the contact pads 350 of the bonding layer 315.
• the protective circuitry layer 410 of the protective chip 300 may then be configured to communicate through the TSVs 330 to the active layer 116 of the active chip 310 across the bond interface.
• the protective chip 300 may comprise a protective circuitry layer 410.
• the protective circuitry layer 410 described herein can be configured to detect or disrupt external access to at least one of the protective chip 300 and the active circuitry 116 of the active chip 310.
• the protective circuitry layer 410 may comprise circuitry, such as throw-away logic, that provides no functional processing to the active chip 310, but that may be configured to detect an intrusion by a hacker in order to protect the active circuitry 116 of the chip 310.
• the circuitry in the protective circuitry layer 410 may be configured to mimic the appearance of sensitive active circuitry.
• a protective chip 300 may incorporate a protective circuitry layer 410 comprising non-sensitive circuits to waste an attacker’s time and prolong the analysis required to identify the sensitive areas of the active chip 310, which can disrupt external access to the active circuitry 116 of the chip 310.
• the protective circuitry layer 410 of the protective chip 300 shown herein may comprise an active circuitry layer.
• the active protective circuitry layer 410 may comprise at least one transistor, e.g., a plurality of transistors.
• the protective circuitry layer 410 may contain circuits to provide additional, non-sensitive functionality to the active chip 310.
• the inexpensive active circuitry in the protective circuitry layer 410 on the protective chip 300 may provide misleading or confusing data to an optical attack as the laser probe is reflected not from the active chip 310 that is to be protected but by the inexpensive low-logic circuitry in the protective circuitry layer 410 on the protective chip 300, which can disrupt external access to the chip 310.
• an attacker employing FIB to drill down to the active chip 310 may cause the active chip 310 to disable or malfunction by ablating the intervening protective circuitry layer 410 of the protective chip 300. If one or more transistors of the protective circuitry layer 410 are destroyed or otherwise altered, the protective circuitry 410 can detect the external access and can transmit an alert to the active circuitry 116 of the chip 310 indicating an intrusion.
• the active chip 310 can disable the functionality of the chip 310, cause the active circuitry 116 to self-destruct or be inactive, or to otherwise prevent external access to the circuitry 116.
• the protective circuitry layer 410 may comprise active circuitry configured to provide a signal or feedback to the active circuitry 116 of the active chip 310. In these embodiments, any errors introduced into the protective layer 410 via ablation from an FIB may cause the signal from the protective layer 410 to cease or change, alerting the active chip 310 that the protective chip 300 has been tampered with.
• the protective layer 410 may comprise active circuitry configured to provide an encrypted timing signal to the active chip 310. If the encrypted timing signal is modified by an external intrusion attempt, the active chip 310 can be alerted to the external access.
• the active circuitry layer of the protective circuitry layer 410 of the protective element 300 or chip may comprise transistors using a legacy node process with larger feature sizes, such as 65nm and larger.
• the protective circuitry layer 410 can be disposed within (e.g., entirely within) the body of the protective element 300.
• the transistors in the protective element 300 may serve to provide a warning to the active chip 310 when the protective chip 300 has been tampered with.
• the active circuitry (e.g., including one or more transistors) in the protective circuitry layer 410 of the protective element 300 may initiate or cause the sensitive circuitry 116 of the active chip 310 to stop working or functioning in a normal manner.
• the protective circuitry 410 inhibits ablative attacks from an FIB.
• the protective materials used in the protective chip 300 may include but are not limited to the protective materials described in U.S. Patent Application No. 16/844,932, filed April 9, 2020, U.S. Patent Application No. 16/844941, filed April 9, 2020, U.S. Patent Application No. 16/881621, filed May 22, 2020, and U.S. Patent Application No. 16/846177, filed April 10, 2020, the entire contents of each of which are incorporated by reference herein in their entirety and for all purposes.
• the protective chip 300 may further comprise an obstructive layer 305 separate and spaced apart vertically from the protective circuitry layer 410.
• the obstructive layer 305 may comprise a plurality of metallization layers 342A,B, separated by an insulation layer 343, that renders the layer 305 opaque to the radiation of a laser probe.
• the obstructive layer 305 may comprise an optical filter.
• An optical filter may be used to alter the optical signal.
• an optical filter may comprise a refractive filter.
• the obstructive layer 305 may cause an attacker’s laser probe to generate inaccurate measurements.
• the obstructive layer can change the direction of an incoming or outgoing beam (e.g. refract), focus or de-focus (e.g. lensing) the beam, scatter the beam, diffuse the beam, diffract the beam (e.g., a grating), phase/wavelength shift the beam, etc.
• the metallization layers 342A,B refer to lightblocking or light-modifying materials that block or modify incident light utilized when attempting to hack sensitive circuitry.
• Figure 4B shows the obstructive layer 305 electrically connected to the circuitry 116 of the active chip 310 by way of the contact pads 350A, 350B and TSVs 330 formed in the active chip.
• the obstructive layer 305 may further comprise a detection circuit.
• the active chip 310 may be configured to respond to changes to one or more properties of the detection circuit in the obstructive layer 305 through the TSVs 330.
• the detection circuit may be configured to enable detection of the resistance of the obstructive layer 305 or a part of the obstructive layer 305 of the protective chip 300.
• the detection circuit may be configured to enable detecting the capacitance of the obstructive layer 305 or a part of the obstructive layer 305 of the protective chip 300.
• the active chip 310 may be able to respond to removal of sufficiently large portions of the protective chip 300.
• an FIB probe may be used to ablate portions of the obstructive layer 305 of the protective chip 300 to expose the sensitive semiconductor layer of the active chip 310. By removing these portions of the protective chip 300, the FIB may alter the capacitance and/or resistance or impedance of the obstructive layer 305 of the protective chip 300 to a degree detectable by the detection circuits.
• the active chip 310 may be configured to shut down when it detects changes to the obstructive layer 305 of the protective chip 300. Additionally or alternatively, the active chip 310 may be configured to emit an alert signal when it detects changes to the obstructive layer 305 of the protective chip 300.
• the obstructive layer 305 of the protective chip 300 may be additionally or alternatively connected to the protective circuitry layer 410 of the protective chip 300 by additional vertical connectors 360.
• the protective layer 410 of the protective chip 300 may be further configured to respond to changes to the properties of the obstructive layer 305 of the protective chip 300.
• the protective circuitry layer 410 of the protective chip 300 may be configured to disable the active chip 310 when changes to the protective chip 300 are detected.
• the obstructive layer 305 of the protective chip 300 may be disposed between the protective layer 410 of the protective chip 300 and the active layer 116 of the active chip 310. It should be understood by one skilled in the art that this is for illustrative purposes only. In other embodiments, the protective layer 410 of the protective chip 300 may be between an obstructive layer 305 of the protective chip 300 and the active layer of the active chip 310. Further, in some embodiments the protective chip 300 may have multiple protective layers 410. Additionally or alternatively, the protective chip 300 may have multiple obstructive layers 305. In these embodiments, the layers may be disposed in the protective chip 300 in any order.
• the protective chip 300 is bonded to the backside 112 of the active chip 310.
• the protective circuitry layer 410 of the protective element 300 and the obstructive layer 305 of the protective element 300 are spaced apart (i.e. distance d) from one another along a direction transverse to the bonding interface 315.
• the obstruction layer 305 may be located on either the protective chip 300, the active chip 310, or both.
• the spacing or distance D between the obstructive layer 305 of the protective element 300 and the active circuitry 116 of the semiconductor element or active chip 310 is at least 20 micrometers. In some embodiments, the distance D can be between 20 micrometers and 100 micrometers, for example, between 50 micrometers and 100 micrometers. In some embodiments, the distance D can be between 100 micrometers and 500 micrometers.
• the protective chip 300 may also comprise a protective circuitry layer 410 comprising an active circuitry layer.
• the protective element 300 may be contain circuits to provide additional, non-sensitive functionality to the active chip 310.
• the protective chip 300 may comprise multiple obstructive layer 305s. In addition to adding distance between the top obstructive layer 305 and the active layer 116 of the active chip 310, in these embodiments an FIB attack would need to ablate through the multiple obstructive layers 305 in order to expose the sensitive semiconductor layer (e.g., active circuitry 116) of the active chip 310.
• the protective element 300 can additionally or alternatively be bonded to the front side 314 to provide front side protection of the circuitry.
• the bonded structure may include a second protective element 300 directly bonded to a front side of the semiconductor element 310 without an adhesive along a second bonding interface 315, the second protective element 300 including a second obstructive layer 305 configured to inhibit external access to at least the frontside 114 of the semiconductor element 310; and a second protective circuitry layer 410 disposed within the protective element 300, the protective circuit layer 410 configured to detect or disrupt external access to the front side 114 of the semiconductor element 300.
• Various embodiments disclosed herein relate to directly bonded structures in which two elements can be directly bonded to one another without an intervening adhesive.
• Two or more semiconductor elements such as integrated device dies, wafers, etc., e.g. elements 300, 310) may be stacked on or bonded to one another to form a bonded structure.
• Conductive contact features or pads (e.g. 350A,B) of one element may be electrically connected to corresponding conductive contact features (e.g. 350A,B) of another element. Any suitable number of elements can be stacked in the bonded structure.
• the elements are directly bonded to one another without an adhesive.
• a non-conductive or dielectric material (e.g. 341 A) of a first element e.g., a protective or occlusive element
• a corresponding non-conductive or dielectric field region (e.g. 341B) of a second element e.g., an active chip
• the non-conductive material can be referred to as a nonconductive bonding region or bonding layer of the first element.
• the non-conductive material of the first element can be directly bonded to the corresponding nonconductive material of the second element using dielectric-to-dielectric bonding techniques.
• hybrid direct bonds can be formed without an intervening adhesive.
• dielectric bonding surfaces can be polished to a high degree of smoothness.
• the bonding surfaces can be cleaned and exposed to a plasma and/or etchants to activate the surfaces.
• the surfaces can be terminated with a species after activation or during activation (e.g., during the plasma and/or etch processes).
• the activation process can be performed to break chemical bonds at the bonding surface, and the termination process can provide additional chemical species at the bonding surface that improves the bonding energy during direct bonding.
• the activation and termination are provided in the same step, e.g., a plasma or wet etchant to activate and terminate the surfaces.
• the bonding surface can be terminated in a separate treatment to provide the additional species for direct bonding.
• the terminating species can comprise nitrogen.
• the bonding surfaces can be exposed to fluorine. For example, there may be one or multiple fluorine peaks near layer and/or bonding interfaces. Thus, in the directly bonded structures, the bonding interface between two dielectric materials can comprise a very smooth interface with higher nitrogen content and/or fluorine peaks at the bonding interface. Additional examples of activation and/or termination treatments may be found throughout U.S. Patent Nos. 9,564,414; 9,391,143; and 10,434,749, the entire contents of each of which are incorporated by reference herein in their entirety and for all purposes.
• conductive contact pads of the first element can also be directly bonded to corresponding conductive contact pads of the second element.
• a hybrid bonding technique can be used to provide conductor-to-conductor direct bonds along a bond interface (e.g. 315) that includes covalently direct bonded dielectric-to- dielectric surfaces, prepared as described above.
• the conductor-to- conductor (e.g., contact pad to contact pad) direct bonds and the dielectric-to-dielectric hybrid bonds can be formed using the direct bonding techniques disclosed at least in U.S. Patent Nos. 9,716,033 and 9,852,988, the entire contents of each of which are incorporated by reference herein in their entirety and for all purposes.
• dielectric bonding surfaces can be prepared and directly bonded to one another without an intervening adhesive as explained above.
• Conductive contact pads (which may be surrounded by nonconductive dielectric field regions) may also directly bond to one another without an intervening adhesive.
• the respective contact pads can be recessed below exterior (e.g., upper) surfaces of the dielectric field or nonconductive bonding regions, for example, recessed by less than 30 nm, less than 20 nm, less than 15 nm, or less than 10 nm, for example, recessed in a range of 2 nm to 20 nm, or in a range of 4 nm to 10 nm.
• the ratio of the pitch of the bonding pads to one of the dimensions of the bonding pad is less than 5, or less than 3 and sometimes desirably less than 2.
• the width of the conductive traces embedded in the bonding surface of one of the bonded elements may range between 0.3 to 3 microns.
• the contact pads and/or traces can comprise copper, although other metals may be suitable.
• a first element can be directly bonded to a second element without an intervening adhesive.
• the first element can comprise a singulated element, such as a singulated integrated device die or singulated protective element.
• the first element can comprise a carrier or substrate (e.g., a wafer) that includes a plurality (e.g., tens, hundreds, or more) of device regions that, when singulated, form a plurality of integrated device dies.
• the second element can comprise a singulated element, such as a singulated integrated device die.
• the second element can comprise a carrier or substrate (e.g., a wafer).
• the first and second elements can be directly bonded to one another without an adhesive, which is different from a deposition process.
• a width of the first element in the bonded structure can be similar to a width of the second element.
• a width of the first element in the bonded structure can be different from a width of the second element.
• the width or area of the larger element in the bonded structure may be at least 10% larger than the width or area of the smaller element.
• the first and second elements can accordingly comprise non-deposited elements.
• directly bonded structures unlike deposited layers, can include a defect region along the bond interface in which nanovoids are present.
• the nanovoids may be formed due to activation of the bonding surfaces (e.g., exposure to a plasma).
• the bond interface can include concentration of materials from the activation and/or last chemical treatment processes.
• a nitrogen peak can be formed at the bond interface.
• an oxygen peak can be formed at the bond interface.
• the bond interface can comprise silicon oxynitride, silicon oxycarbonitride, or silicon carbonitride.
• the direct bond can comprise a covalent bond, which is stronger than van Der Waals bonds.
• the bonding layers can also comprise polished surfaces that are planarized to a high degree of smoothness.
• a bonded structure in one aspect, includes a semiconductor element, including active circuitry (e.g. 116).
• the bonded structure also includes a protective element directly bonded to the semiconductor element without an adhesive along a bonding interface.
• the protective element includes an obstructive layer (i.e. 305) configured to inhibit external access to at least a portion of the active circuitry.
• the protective element may also include, additionally or alternatively, a protective circuitry layer (e.g. 410) disposed within it, and the protective circuitry layer is configured to detect or disrupt external access to the protective element, the active circuitry of the semiconductor element, or both.
• the protective circuitry layer of the protective element is disposed between the obstructive layer of the protective element and the bond interface. In some embodiments, the obstructive layer of the protective element is disposed between the protective circuitry layer of the protective element and the bond interface. In some embodiments, the obstructive layer of the protective element includes an occlusive layer configured to occlude a predefined area of the semiconductor element in the plane parallel to the layer’s surface. In some embodiments, the protective element includes a bonding layer directly bonded to a bonding layer of the semiconductor element. In some embodiments, the bonding layer of the protective element is metallized in a pattern that matches at least a portion of a metallization pattern of a bonding layer of the protective element.
• the bonding layer of the semiconductor element includes a number of contact pads disposed in a nonconductive layer
• the bonding layer of the protective element includes a number of contact pads disposed in a nonconductive layer directly bonded to the contact pads of the semiconductor element.
• the bonding layer of the protective element and the protective circuitry layer of the protective element are connected through one or more vertical interconnects (e.g. 360).
• the obstructive layer of the protective element includes a detection circuit configured to detect external access of the protective element.
• the detection circuit includes a passive electronic circuit element configured to detect external access.
• the passive electronic circuit includes a capacitive circuit element, a resistive circuit element, or both.
• the protective circuitry layer of the protective element includes active circuitry.
• the active circuitry of the protective circuitry layer is configured to emit an encrypted timing signal.
• the active circuitry of the protective circuitry layer is configured to detect changes to the protective circuitry layer.
• the active circuitry of the protective circuitry layer is configured to disable the active circuitry of the semiconductor when it detects a change to the protective circuitry layer.
• the protective circuitry layer is configured to emit an alarm signal when the active circuitry of the protective circuitry layer detects a change to the protective circuitry layer.
• a vertical interconnect extends from the protective circuitry layer to a contact pad of the protective element.
• the protective element is directly bonded to a back side (e.g. 112) of the semiconductor element opposite an active side (e.g. 114), and a through semiconductor via (e.g. 330) extends from a contact pad at or near the active side of the semiconductor element to a contact pad of the protective element providing electrical communication between the semiconductor element and the protective circuitry layer of the protective element.
• the protective circuitry layer is completely embedded within the protective element.
• a method for forming a bonded structure.
• the method includes directly bonding a semiconductor element to a protective element without an adhesive.
• the semiconductor element includes active circuitry
• the protective element includes an obstructive layer configured to inhibit external access to a portion of the active circuitry and a protective layer configured to detect or disrupt external access to the protective element, the semiconductor element, or both.
• the method includes forming the protective element to include a bonding layer, forming the semiconductor element to include a bonding layer, and bonding the bonding layer of the protective element to the bonding layer of the semiconductor element.
• the method includes forming the protective element such that the bonding layer of the protective element is metallized to match a metallization pattern of the semiconductor element.
• the method includes forming the protective element such that the bonding layer of the protective element includes a number of contact pads disposed in a nonconductive layer configured to mirror a plurality of contact pads of the bonding layer of the semiconductor element.
• the method includes forming the protective element such that the obstructive layer includes a detection circuit configured to detect external access to the protective element.
• the method includes forming the protective element to include a vertical interconnect extending from the detection circuit to a contact pad of the protective element. In some embodiments, the method includes directly bonding the protective element to a back side of the semiconductor element that is directly opposite an active side of the semiconductor element, and forming the semiconductor element to include a through semiconductor via (TSV) extending from a contact pad at or near the active side of the semiconductor to a contact pad of the protective element such that the TSV provides electrical communication between the semiconductor element and the detection circuit. In some embodiments, the method includes forming the protective element to include a vertical interconnect extending from the detection circuit to the protective layer of the protective element, and a second vertical interconnect extending from the protective layer of the protective element to a contact pad of the protective element.
• TSV through semiconductor via
• the method includes forming the protective circuitry layer to include a passive electronic circuit configured to mimic the appearance of active circuitry. In some embodiments, the method includes forming the protective circuitry layer to include active circuitry. In some embodiments, the method includes configuring the active circuitry of the protective circuitry layer to emit an encrypted timing signal. In some embodiments, the method includes configuring the active circuitry of the protective circuitry layer to detect changes to the protective circuitry layer. In some embodiments, the method includes configuring the active circuitry of the protective circuitry layer to disable the active circuitry of the semiconductor element when the active circuitry of the protective circuitry layer detects a change to the protective circuitry layer.
• the method includes configuring the active circuitry of the protective circuitry layer to emit an alarm signal when the active circuitry of the protective circuitry layer detects a change to the protective circuitry layer.
• the method includes forming the protective element to include a vertical interconnect extending from the protective circuitry layer to a contact pad of the protective element.
• the method includes directly bonding the protective element to a back side of the semiconductor element that is directly opposite an active side of the semiconductor element, and forming the semiconductor element to include a through semiconductor via (TSV) extending from a contact pad at or near the active side of the semiconductor to a contact pad of the protective element such that the TSV provides electrical communication between the semiconductor element and the protective layer of the protective element.
• the method includes forming the protective element such that the protective circuitry layer is completely embedded within the protective element.
• a bonded structure in another aspect, includes a semiconductor element that includes active circuitry, and a protective element that is directly bonded to the semiconductor element without an adhesive along a bonding interface.
• the protective element includes a protective circuitry layer configured to detect or disrupt external access to the protective element, the active circuitry of the semiconductor element, or both.
• the protective layer of the protective element and the active circuitry of the semiconductor element are spaced apart from one another along a direction transverse to the bonding interface. In some embodiments, the spacing between the obstructive layer of the protective element and the active circuitry of the semiconductor element is at least 20 micrometers.
• the protective element includes a bonding layer, and the semiconductor element includes a bonding layer directly bonded to the bonding layer of the protective element. In some embodiments, the bonding layer of the protective element is metallized to match a metallization pattern of the semiconductor element.
• the bonding layer of the semiconductor element includes a number of contact pads disposed in a nonconductive layer
• the bonding layer of the protective element includes a number of contact pads disposed in a nonconductive layer directly bonded to the contact pads of the semiconductor element.
• the protective layer of the protective element includes a passive electronic circuit configured to mimic the appearance of active circuitry.
• the protective layer of the protective element includes active circuitry.
• the active circuitry of the protective circuitry layer is configured to emit an encrypted timing signal.
• the active circuitry of the protective circuitry layer is configured to detect changes to the protective element.
• the active circuitry of the protective circuitry layer is configured to disable the active circuitry of the semiconductor element when the active circuitry of the protective circuitry layer detects a change to the protective element.
• the protective circuitry layer is configured to emit an alarm signal when it detects a change to the protective element.
• the bonded structure includes a vertical interconnect extending from the protective layer of the protective element to a contact pad of the protective element.
• the protective element is directly bonded to a back side of the semiconductor element opposite an active side, and a through semiconductor via (TSV) extends from a contact pad at or near the active side of the semiconductor element to a contact pad of the protective element, such that the TSV provides electrical communication between the semiconductor element and the protective layer of the protective element.
• TSV through semiconductor via
• the protective circuitry layer of the protective element is completely embedded within the protective element.
• the words “herein,” “above,” “below,” and words of similar import when used in this application, shall refer to this application as a whole and not to any particular portions of this application.
• first element when a first element is described as being “on” or “over” a second element, the first element may be directly on or over the second element, such that the first and second elements directly contact, or the first element may be indirectly on or over the second element such that one or more elements intervene between the first and second elements.
• words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively.
• the word “or” in reference to a list of two or more items that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.
• conditional language used herein such as, among others, “can,” “could,” “might,” “may,” “e.g.,” “for example,” “such as” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments.

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• 2022
  • 2022-07-29 JP JP2024506506A patent/JP2024528964A/ja active Pending
  • 2022-07-29 US US17/816,346 patent/US12300634B2/en active Active
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• 2025
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