Methods for fusion bonding semiconductor devices to temporary carrier wafers with cavity regions for reduced bond strength, and semiconductor device assemblies formed by the same
12582001 ยท 2026-03-17
Assignee
Inventors
- Wei Zhou (Boise, ID, US)
- Bret K. Street (Meridian, ID, US)
- Terrence B. McDaniel (Boise, ID, US)
- Amy R. Griffin (Boise, ID, US)
- Kyle K. Kirby (Eagle, ID, US)
- Thiagarajan Raman (Boise, ID, US)
Cpc classification
H10W74/121
ELECTRICITY
H10W90/26
ELECTRICITY
H10W72/942
ELECTRICITY
H10W90/297
ELECTRICITY
H10B80/00
ELECTRICITY
H10W99/00
ELECTRICITY
H10W80/211
ELECTRICITY
H10P72/7434
ELECTRICITY
H10P72/744
ELECTRICITY
International classification
Abstract
Methods of making a semiconductor device assembly are provided. The methods can comprise providing a first semiconductor device having a first dielectric material at a first surface, providing a carrier wafer having a second dielectric material at a second surface, and forming a dielectric-dielectric bond between the first dielectric material and the second dielectric material. At least one of the first surface and the second surface includes a cavity configured to entrap a gas during the formation of the bond. The method can further include stacking one or more second semiconductor devices over the first semiconductor device to form the semiconductor device assembly, and removing the semiconductor device assembly from the carrier wafer.
Claims
1. A method of making a semiconductor device assembly, the method comprising: providing a first semiconductor device having a first dielectric material at a first surface; providing a carrier wafer having a second dielectric material at a second surface; forming a dielectric-dielectric bond between the first dielectric material and the second dielectric material, wherein the first surface includes a cavity configured to entrap a gas during the formation of the dielectric-dielectric bond; stacking one or more second semiconductor devices over the first semiconductor device to form the semiconductor device assembly; and removing the semiconductor device assembly from the carrier wafer.
2. The method of claim 1, wherein the first surface is an active surface of the first semiconductor device that further includes metal interconnects.
3. The method of claim 1, wherein the second surface includes a second cavity configured to entrap the gas during the formation of the dielectric-dielectric bond.
4. The method of claim 1, wherein the cavity has an area equal to at least 25% of a footprint of the first semiconductor device.
5. The method of claim 1, wherein the first surface further includes a second cavity.
6. A method of making a semiconductor device assembly, the method comprising: providing a first semiconductor device having a first dielectric material at a first surface; providing a carrier wafer having a second dielectric material at a second surface; forming a dielectric-dielectric bond between the first dielectric material and the second dielectric material, wherein at least one of the first surface and the second surface includes a cavity configured to entrap a gas during the formation of the dielectric-dielectric bond; stacking one or more second semiconductor devices over the first semiconductor device to form the semiconductor device assembly; and removing the semiconductor device assembly from the carrier wafer, wherein removing the semiconductor device assembly from the carrier wafer includes increasing a pressure of the entrapped gas in the cavity.
7. The method of claim 6, wherein increasing the pressure of the entrapped gas in the cavity includes heating the entrapped gas in the cavity.
8. The method of claim 7, wherein heating the entrapped gas in the cavity includes providing power to a heater adjacent the cavity.
9. The method of claim 8, wherein the heater is formed in the first semiconductor device.
10. The method of claim 8, wherein the heater is formed in the carrier wafer.
11. The method of claim 6, wherein: the second surface includes the cavity, a channel is formed through the carrier wafer, and the method further comprising introducing the gas into the cavity.
12. The method of claim 11, wherein increasing the pressure of the entrapped gas comprises introducing the gas into the cavity such that the pressure of the entrapped gas is greater than a pressure of gasses surrounding the first semiconductor device.
13. The method of claim 12, wherein increasing the pressure of the entrapped gas further comprises heating the entrapped gas in the cavity concurrently with introducing the gas into the cavity.
14. The method of claim 6, wherein respective dielectric materials at respective surfaces of the one or more second semiconductor devices exclude cavities configured to entrap gas.
15. The method of claim 6, wherein: the second surface includes the cavity, and the first surface includes a mechanically-altered region corresponding to a location of the cavity on the second surface.
16. A method of processing a semiconductor device, the method comprising: providing the semiconductor device having a first dielectric material at a first surface; providing a carrier wafer having a second dielectric material at a second surface; forming a dielectric-dielectric bond between the first dielectric material and the second dielectric material, wherein the first surface includes a cavity configured to entrap a gas during the formation of the dielectric-dielectric bond; performing wafer-level processing on the semiconductor device while the semiconductor device is bonded to the carrier wafer; and removing the semiconductor device from the carrier wafer.
17. The method of claim 16, wherein removing the semiconductor device from the carrier wafer includes heating the entrapped gas in the cavity.
18. The method of claim 17, wherein heating the entrapped gas in the cavity includes providing power to a heater adjacent the cavity.
19. The method of claim 18, wherein the heater is formed in the semiconductor device.
20. The method of claim 18, wherein the heater is formed in the carrier wafer.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
(7) The formation of many semiconductor device assemblies can involve temporarily bonding a chip to a carrier wafer (C2W) to enable wafer-level processing steps to be performed on semiconductor devices already singulated from another wafer (e.g., known good die) (KGD)). One challenge with temporarily bonding a semiconductor device is balancing the strength of the bond with the ease of subsequent removal. A bond that is too strong (e.g., a fusion or dielectric-dielectric bond between large facing regions of passivation material on surfaces of both the die and the carrier wafer) can interfere with removal of the die from the carrier wafer, potentially causing damage to the die, the carrier wafer, or both. A bond that is insufficiently strong (e.g., a temporary adhesive) can permit movement of the semiconductor device relative to the carrier wafer, potentially causing alignment issues or other processing challenges that can reduce yield. Moreover, adhesives can require subsequent cleaning steps that present their own challengescost, tooling compatibility, etc.
(8) To address these drawbacks and others, various embodiments of the present application provide improved approaches for temporarily bonding a semiconductor device to a carrier wafer. In this regard, embodiment of the present disclosure provide a method in which a dielectric-dielectric bond is formed between a first dielectric material at a first surface of a semiconductor device and a second dielectric material at a second surface of a carrier wafer, wherein at least one of the first surface and the second surface including a cavity configured to entrap a gas during the formation of the dielectric-dielectric bond. The cavity may be provided at the first surface of the semiconductor device, at the second surface of the carrier wafer, or both. The cavity reduces the area of the dielectric-dielectric bond between the semiconductor device and the carrier wafer, thereby reducing the force necessary to separate them.
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(10) Although in the foregoing example embodiment, the cavities 117 are illustrated and described as being formed at a surface of the semiconductor device 110, in other embodiments a carrier wafer may instead include similar cavities. One such arrangement is shown in
(11) As can be seen with reference to
(12) According to one aspect of the present disclosure, the relative area of the cavities to areas where a dielectric bond is formed (e.g., in a non-interconnect area excluding the area of any metal contact pads facing the carrier wafer) may be selected based on a desired bond strength between a semiconductor die and a carrier wafer. For example, in various embodiments, the non-interconnect area (e.g., the area of the footprint of the semiconductor device exclusive of the area of the contact pads of the semiconductor device) may comprise more than 25% cavities, more than 33% cavities, more than 50% cavities, or even more than 67% cavities.
(13) According to another aspect of the present disclosure, gas (e.g., atmospheric air, environmental gasses present during the fusion bonding process, etc.) may be entrapped within a cavity between a semiconductor device and a carrier wafer, and be intentionally expanded by the application of heat during a de-bonding process to facilitate the removal of the semiconductor device from the carrier wafer. For example, the debonding process can be accompanied by the external application of heat (e.g., by performing the operation in an oven, or with the carrier wafer on a heated surface), or in other embodiments by the internal generation of heat. For example, an electric heater (e.g., exploiting the Joule/resistive heating effect) can be included in a semiconductor device (or in a carrier wafer) and coupled to an external power source to heat and expand the entrapped gas in a cavity during a de-bonding operation to reduce the external force required to separate a semiconductor device and a carrier wafer.
(14) As can be seen with reference to
(15) Additionally or alternatively, in accordance with another aspect of the present disclosure, cavities in a semiconductor device or in a carrier wafer that reduce the bonding area between the semiconductor device and the carrier wafer can be further connected to an external source of pressurized gasses, to similarly reduce the external force required to separate a semiconductor device and a carrier wafer. For example,
(16) As can be seen with reference to
(17) According to one aspect of the present disclosure, the relative area of the cavities to areas where a dielectric bond is formed (e.g., in a non-interconnect area excluding the area of any metal contact pads facing the carrier wafer) may be selected based on a desired bond strength between a semiconductor die and a carrier wafer. For example, in various embodiments, the non-interconnect area (e.g., the area of the footprint of the semiconductor device exclusive of the area of the contact pads of the semiconductor device) may comprise more than 25% cavities, more than 33% cavities, more than 50% cavities, or even more than 67% cavities.
(18) According to another aspect of the present disclosure, gas (e.g., atmospheric air, environmental gasses present during the fusion bonding process, etc.) may be introduced to the cavities 403 between a semiconductor device and a carrier wafer by channels 404 provided through the carrier wafer 400. By pressurizing the gases thus introduced during a de-bonding process, the removal of the semiconductor device from the carrier wafer may be facilitated (e.g., either by pressure alone, or in combination with applied by heaters in the semiconductor device 410 such as are illustrated above with reference to
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(20) Turning to
(21) According to various aspects of the present disclosure, the controllable strength of the bond between a carrier wafer and a semiconductor device provided by the foregoing approaches can facilitate the manufacture of semiconductor device assemblies. For example,
(22) Alternatively, rather than removing the stack 750 as shown in
(23) Although in the foregoing examples, a second carrier wafer is described and illustrated as being attached to a semiconductor device by adhesive, in other embodiments a second carrier wafer could be bonded to a semiconductor device in a similar manner to that described above with reference to a first carrier wafernamely by a dielectric-dielectric bond mediated by one or more cavities on the second carrier wafer, the semiconductor device, or both.
(24) According to various aspects of the present disclosure, a semiconductor device may be bonded by a cavity-material-mediated dielectric-dielectric bond either at the active surface of the semiconductor device or at the back surface of the semiconductor device. For example,
(25) Although in the foregoing examples, semiconductor device assemblies have been illustrated and described as including an outermost semiconductor device with an exterior surface on which are formed one or more cavities in a layer of dielectric material, in other embodiments in which cavities are provided only on a carrier wafer (e.g., carrier wafer 200 in
(26) For example,
(27) Although the mechanically-altered regions of semiconductor device assembly 1500 are illustrated as laterally-spaced apart from interconnect structures and surrounded by portions of dielectric material 211 that are not mechanically-altered, in other embodiments of the present disclosure other arrangements of mechanically-altered regions with other positions, shapes, sizes, and spatial relationships to interconnects and die edges may be implemented. For example,
(28) In accordance with one aspect of the present disclosure, the semiconductor devices illustrated in the assemblies of
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(31) Any one of the semiconductor devices and semiconductor device assemblies described above with reference to
(32) Specific details of several embodiments of semiconductor devices, and associated systems and methods, are described above. A person skilled in the relevant art will recognize that suitable stages of the methods described herein can be performed at the wafer level or at the die level. Therefore, depending upon the context in which it is used, the term substrate can refer to a wafer-level substrate or to a singulated, die-level substrate. Furthermore, unless the context indicates otherwise, structures disclosed herein can be formed using conventional semiconductor-manufacturing techniques. Materials can be deposited, for example, using chemical vapor deposition, physical vapor deposition, atomic layer deposition, plating, electroless plating, spin coating, and/or other suitable techniques. Similarly, materials can be removed, for example, using plasma etching, wet etching, chemical-mechanical planarization, or other suitable techniques.
(33) The devices discussed herein, including a memory device, may be formed on a semiconductor substrate or die, such as silicon, germanium, silicon-germanium alloy, gallium arsenide, gallium nitride, etc. In some cases, the substrate is a semiconductor wafer. In other cases, the substrate may be a silicon-on-insulator (SOI) substrate, such as silicon-on-glass (SOG) or silicon-on-sapphire (SOP), or epitaxial layers of semiconductor materials on another substrate. The conductivity of the substrate, or sub-regions of the substrate, may be controlled through doping using various chemical species including, but not limited to, phosphorous, boron, or arsenic. Doping may be performed during the initial formation or growth of the substrate, by ion-implantation, or by any other doping means.
(34) The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. Other examples and implementations are within the scope of the disclosure and appended claims. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.
(35) As used herein, including in the claims, or as used in a list of items (for example, a list of items prefaced by a phrase such as at least one of or one or more of) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase based on shall not be construed as a reference to a closed set of conditions. For example, an exemplary step that is described as based on condition A may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase based on shall be construed in the same manner as the phrase based at least in part on.
(36) As used herein, the terms vertical, lateral, upper, lower, above, and below can refer to relative directions or positions of features in the semiconductor devices in view of the orientation shown in the Figures. For example, upper or uppermost can refer to a feature positioned closer to the top of a page than another feature. These terms, however, should be construed broadly to include semiconductor devices having other orientations, such as inverted or inclined orientations where top/bottom, over/under, above/below, up/down, and left/right can be interchanged depending on the orientation.
(37) It should be noted that the methods described above describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Furthermore, embodiments from two or more of the methods may be combined.
(38) From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the scope of the invention. Rather, in the foregoing description, numerous specific details are discussed to provide a thorough and enabling description for embodiments of the present technology. One skilled in the relevant art, however, will recognize that the disclosure can be practiced without one or more of the specific details. In other instances, well-known structures or operations often associated with memory systems and devices are not shown, or are not described in detail, to avoid obscuring other aspects of the technology. In general, it should be understood that various other devices, systems, and methods in addition to those specific embodiments disclosed herein may be within the scope of the present technology.