Hybrid bonding substrates and related methods

Abstract

The present disclosure relates to hybrid bonding substrates and related methods. A particular implementation of an image sensor package can include an image sensor die including a via and a trench, both proximate to a seal ring, and a second die hybrid bonded to the image sensor die. The via can extend into a thickness of the second die to a bonding pad included in the second die, and the trench can extend into the thickness of the second die.

Description

Technical Field

[0001] This document covers various aspects of semiconductor devices, such as image sensor devices. Background Technology

[0002] Image sensor devices operate by converting electromagnetic radiation, received as photons, into electrons and holes in a semiconductor substrate. These electrons and holes are then collected and processed. The number of electrons and holes in each pixel of the pixel array produces an image of the electromagnetic radiation received by the image sensor device. Summary of the Invention

[0003] Specific implementations of an image sensor package may include: an image sensor die including vias and trenches, both adjacent to a sealing ring; and a second die bonded to the image sensor die by hybrid bonding, the second die including a bonding pad. The vias may extend into the thickness of the second die to reach the bonding pads, and the trenches may extend into the thickness of the second die.

[0004] Specific implementations of the image sensor package may include one, all, or any of the following:

[0005] The groove can be located between the scribed area of ​​the image sensor die and the sealing ring.

[0006] Through-holes can extend deeper into the thickness of the second die than through-holes.

[0007] The trench may be unfilled.

[0008] Microlens materials or planar materials can fill the grooves.

[0009] The image sensor die may also include a microlens array coupled to a color filter array coupled to a pixel array.

[0010] The groove can extend beyond the corners of the image sensor die.

[0011] A specific implementation of the method for forming an image sensor package may include: providing an image sensor die and a second die; co-bonding the image sensor die and the second die; forming a patterned layer on a pixel array included in the largest planar surface of the image sensor die; and simultaneously etching vias and trenches using the patterned layer, the vias and trenches being adjacent to a sealing ring, the vias and trenches extending through the thickness of the image sensor die and into the thickness of the second die.

[0012] Specific implementations of the method for forming an image sensor package may include one, all, or any of the following:

[0013] The method may include removing the patterned layer and isolating the image sensor die and the second die adjacent to the trench.

[0014] The method may also include monomerization using sawing.

[0015] The method may include stopping the etching of the via at the bonding pad included in the second die.

[0016] The method may include applying an over-etching time during etching to cause the trench to extend deeper than the through-hole through the thickness of the second die.

[0017] The method may include: forming a color filter array on a pixel array; and forming a microlens on the color filter array.

[0018] The method may include: forming a color filter array on a pixel array; forming microlenses on the color filter array using a microlens material; and filling grooves with the microlens material while forming the microlenses.

[0019] The method may include removing microlens material from the trench.

[0020] The method may include: forming a color filter array on a pixel array; forming microlenses on the color filter array using a microlens material without filling the grooves with the microlens material.

[0021] Specific implementations of the image sensor package may include: an image sensor die; a second die bonded to the image sensor die by hybrid bonding; and vias and trenches, both of which extend into the thickness of the second die by hybrid bonding. The trenches may extend into the thickness of the second die by hybrid bonding and extend completely around the periphery of the image sensor die.

[0022] Specific implementations of the image sensor package may include one, all, or any of the following:

[0023] The groove can be located between the scribed area of ​​the image sensor die and the sealing ring.

[0024] The trench may be unfilled.

[0025] Microlens materials or planar materials can fill the grooves.

[0026] The above and other aspects, features and advantages will become apparent to those skilled in the art from the detailed description and accompanying drawings, as well as from the claims. Attached Figure Description

[0027] Specific embodiments will be described below in conjunction with the accompanying drawings, in which similar reference numerals denote similar elements, and:

[0028] Figure 1 This is a cross-sectional view of a specific embodiment of an image sensor device, which includes an image sensor die hybridally bonded to a second die;

[0029] Figure 2 This is a cross-sectional view of another specific embodiment of an image sensor device, which includes an image sensor die hybridally bonded to a second die;

[0030] Figure 3 This is a cross-sectional view of another specific embodiment of the image sensor device, showing the scribing / die channel;

[0031] Figure 4 This is a top perspective view of a specific implementation of an image sensor device, showing the specific implementation of the trench;

[0032] Figure 5 yes Figure 4 A top view of a specific implementation of an image sensor device;

[0033] Figure 6 It is a cross-sectional view of the specific implementation of the image sensor device after the bonding and patterning operations;

[0034] Figure 7 yes Figure 6 The image sensor device is specifically implemented in a cross-sectional view after the etching operation;

[0035] Figure 8 yes Figure 7 The image sensor device is specifically implemented in a cross-sectional view after the pattern removal operation;

[0036] Figure 9 It is a cross-sectional view of an image sensor device after a color filter array and a microlens array have been formed on it; and

[0037] Figure 10 It is a cross-sectional view of the specific implementation of the image sensor device after a color filter array and a microlens array (where the grooves are filled with microlens material) have been formed on it. Detailed Implementation

[0038] This disclosure, its aspects, and specific embodiments are not limited to the specific components, assembly steps, or method elements disclosed herein. Many other components, assembly steps, and / or method elements known in the art that conform to the intended image sensor package will be readily apparent and can be used with specific embodiments of this disclosure. Therefore, for example, although specific embodiments are disclosed herein, such embodiments and implementation components may include any shape, size, style, type, model, version, measure, concentration, material, quantity, method element, step, etc., known in the art for such image sensor packages and implementation components and methods that conform to the intended operation and methods.

[0039] During the fabrication of an image sensor device, a first die (such as an image sensor die) may be bonded to a second die (or one or more additional dies). The second die can be any of a wide variety of semiconductor die types, including, as non-limiting examples, digital signal processors, microprocessors, field-programmable gate arrays (FPGAs), memories, random access memory, flash memory, electrically erasable programmable read-only memory (EEPROM), interpolator dies, or any other semiconductor device or die type. Hybrid bonding involves bonding the dielectric surface of the first die to the dielectric surface of the second die, and bonding metal embedded in the first die to metal embedded in the second die. The dielectric can be a semiconductor substrate material, such as silicon oxide, and the metal can be copper or other metals suitable for hybrid bonding techniques. The bonding of the embedded metal of the first die to the embedded metal of the second die forms a hybrid bonding metal interconnect. Embedded metal placed for hybrid bonding purposes may also be referred to herein as "hybrid bonding metal".

[0040] Following bonding and other processing, a single stacked die can include an array of image sensor devices, with image sensors in one die connected to electrical components on a second die. The image sensor devices can then be singulated from the array. When singulation is performed using mechanical processes (such as sawing or jet ablation), cracks can form in the hybrid bonding interface of the image sensor die, the second die, and / or adjacent to the blade / jettor. These cracks can propagate into the die or begin to break / delaminate the hybrid bond, resulting in immediate yield losses or potential reliability failures as the device is used under thermal or mechanical stress for extended periods.

[0041] In this document, the term "through-silicon via" is used. However, in various specific embodiments, the semiconductor substrate material used to form the image sensor die and the second die can be many other semiconductor substrate types, including, as non-limiting examples, silicon carbide, silicon-on-insulator, glass, silicon dioxide, gallium arsenide, ruby, sapphire, or any other semiconductor substrate type. Therefore, as used herein, for the sake of simplicity, the term "through-silicon via" also includes vias extending through the material of the particular semiconductor substrate type in which they are formed, including vias extending through interlayer dielectrics and other insulating materials, such as through-oxide vias.

[0042] While the principles described herein are set in the context of hybrid-bonded image sensor devices, the concepts can be applied to any hybrid-bonded semiconductor device. Therefore, by way of non-limiting example, the principles disclosed herein can be applied to microprocessors, microcontrollers, microprocessors and memory, power semiconductor devices, hybrid-bonded combinations of power semiconductor devices and memory, or any other combination of semiconductor device types. Those skilled in the art will readily understand how the principles disclosed herein can be used to help prevent crack propagation in various bonded semiconductor dies.

[0043] refer to Figure 1 This illustration shows a specific embodiment of an image sensor device 2, which includes an image sensor die 4, which is hybrid-bonded to a second die 6 using complementary metal structures 8 and 10, respectively formed in both dies. The second die 6 can be any type of semiconductor device disclosed herein. The image sensor device 2 includes a through-silicon via 12 extending through the thickness 14 of the image sensor die 4 and down through the hybrid bonding 16 to a pad 18. As shown, a sealing ring structure 20 is formed by the metallization pattern of traces and vias in the die stack of the image sensor die 4. In this specific embodiment, the sealing ring structure does not extend down into the semiconductor substrate material of the image sensor die itself to reach the hybrid bonding 16, which allows cracks to propagate below the sealing ring. The through-silicon via 12 is adjacent to the sealing ring 20.

[0044] refer to Figure 1Also adjacent to the sealing ring 20 is the trench / via 22. As shown, the trench 22 extends through the thickness 14 of the image sensor die, through the hybrid bonding 16, and into the material of the second die 6. The end 24 of the trench 22 is within the material of the second die 6 because there is no pad at that location. Because no pad is used in this embodiment, the end 24 of the trench 22 can extend deeper into the thickness of the second die 6 than the through-silicon via 12, even if the through-silicon via 12 and the trench 22 are etched simultaneously, because there is no etch stop for the trench. In an alternative embodiment, if an etch stop is required for the trench 22, a pad can be formed in the semiconductor substrate material of the second die 6 to prevent further etching of the trench 22 beyond the pad.

[0045] To the right of the trench is the scribe line / die channel 26 of the image sensor device, in which another via 28 has been formed to allow access to the electronic test structure. In various specific embodiments, the structure in this scribe line may be substantially or completely removed during the monomerization of the image sensor device 2, thereby leaving the trench 22 intact or partially or completely removing one side of the so-called monomerized structure. Because the trench 22 extends through the thickness 14 of the image sensor die beyond the hybrid bond 16, any cracks formed in the material of the image sensor die or the second die during monomerization, or any delamination / separation of the hybrid bond 16, are mechanically terminated upon reaching the edge of the trench 22. The gap formed by the trench 22 in the material of the image sensor die 4 and the second die 6 prevents cracks caused by the monomerization operation from propagating into the image sensor die 4, the second die 6, or the hybrid bond 16.

[0046] refer to Figure 2 This illustrates another embodiment of the image sensor device 30, in which the depth of the trench 32 entering the thickness 44 of the second die 34 may be deeper than that of the through-silicon via 36, ​​because in this embodiment there is no etch stop (e.g., pad 38) for the trench 32 during the simultaneous etch process. In this way, the end 40 of the trench 32 can be configured to extend downwards to a sealing ring structure 42 in the die stack of the second die 34, which further prevents any cracks formed in the second die 34 from propagating into the material of the second die 34. An appropriate over-etch time can be set to allow the end 40 of the trench 32 to reach a desired location within the thickness 44 of the second die 34.

[0047] refer to Figure 3This diagram illustrates two semiconductor device embodiments 48, 50 bonded by a scribe line area 46. In this view, the locations of trenches 52, 54 adjacent to the scribe line area 46 prevent crack propagation into the material of the two image sensor dies 56, 58 or the two second dies 60, 62, or prevent delamination along the location of the mixed bond 64. The trenches 52, 54 act as voids to prevent crack propagation beyond the void location during monomerization within the scribe line area 46. During monomerization, the edges of the cut can keep the sides of the trenches 52, 54 intact because the width of the cut can generally correspond to the width indicated by the scribe line area 46. Alternatively, if the width of the cut is wider than the width of the scribe line area 46, depending on the blade's kerf width, the cut can remove some or all of the material from the trench.

[0048] Figure 3 The diagram also illustrates how, in some embodiments, both image sensor dies 56, 58 and second dies 60, 62 can be thinned prior to hybrid bonding. In other embodiments, thinning of image sensor dies 56, 58 and / or second dies 60, 62 can occur after bonding (if applicable). In all these configurations, trenches 52, 54 can be used to prevent cracking and delamination.

[0049] Grooves 52 and 54 also help limit heat transfer during laser scribing. In some image sensor implementations, laser scribing can be used to scribing through at least some of the die stacks in the image sensor's die stack to prevent cracking of the interlayer dielectric material (especially in low-dielectric-constant materials, i.e., low-k materials) during subsequent sawing. Figure 3 The metal regions 66 and 68 shown are used to help absorb laser energy, thereby preventing the cut from extending beyond the scribed region 46. Because Figure 3 The trenches 52 and 54 are not filled with any material, thus reducing heat transfer to the die stack of image sensor dies 56 and 58 during laser operation. Reduced heat transfer helps prevent damage to the active circuitry in the die stack of image sensor dies 56 and 58.

[0050] In various structural and methodological implementations, the trench can extend along one or more sides of the image sensor device. For example... Figures 4 to 5As shown, the image sensor device may have four sides and be square or rectangular. In some embodiments, trenches may exist on all sides of the image sensor device, positioned adjacent to all scribe lines. In embodiments where trenches exist on both sides, the trenches may be adjacent to two parallel scribe lines (such as an X-scribe line or an adjacent Y-scribe line). In some embodiments, the trenches may be adjacent to alternating X-scribe lines, alternating Y-scribe lines, or both alternating X-scribe lines and alternating Y-scribe lines.

[0051] refer to Figure 4 A perspective top view of the image sensor device 70 is shown to illustrate the structure of the bonding and sealing structure; for clarity, details of the pixel array are omitted. In this embodiment, the placement of the hybrid bonding metal 72 within the rectangular image sensor device 70 is shown as extending along one side of the image sensor device 70 in the form of complementaryly arranged metal lines in the upper image sensor die and the lower second die. In other embodiments, the hybrid bonding metal may be located in many other locations, such as, by way of non-limiting example, opposite sides, three sides, all four sides, multiple lines, cross patterns, curved patterns, dot patterns, or any other desired configuration to achieve the desired amount of hybrid bonding between the image sensor die and the second die. Figure 4 The image also shows concentrically arranged sealing rings 74 and 76, with sealing ring 76 located within the periphery of sealing ring 74. Although in Figure 4 The specific implementation shows the use of two sealing rings, but in other image sensor device implementations, a single sealing ring or more than two sealing rings may be used. Furthermore, although the sealing rings are shown as continuous, in some implementations they may consist of discontinuous structures or partial segments. A groove 78 is also shown, and this groove is arranged concentrically around the sealing ring 74.

[0052] refer to Figure 5 A top view of the image sensor device 70 is shown, further illustrating the relative positioning of the hybrid bonding metal 72, sealing rings 74 and 76, and the groove 78. The spacing and proximity between the groove 78 and the sealing ring 74 can be seen here. Figures 4 to 5 In this specific implementation, the sealing rings 74, 76, and trench 78 all extend across the corners of the image sensor device 70, rather than extending outwards adjacent to the corners. Because the corner regions of the die are most prone to chip defects during monomerization via sawing, this extension of the trench 78 across the corners helps minimize the probability of the chip crossing the trench of any particular die. In other implementations of the image sensor device, the sealing rings 74, 76, and trench may extend to the corners, thereby maintaining equal spacing along all four sides of the image sensor device 70.

[0053] The spacing between the trench 78 and the sealing ring 74 can be determined by the desired trench width and / or the desired degree of crack mitigation. The trench 78 forms the first line of defense against cracking and chipping. The width of the trench 78 can vary based on available area, tooling etching limitations, substrate material, etc. A wider spacing between the trench 78 and the sealing ring 74 will provide additional margin, thus providing more protection, while a narrower spacing will provide less margin or less protection. Although Figures 4 to 5 The trench embodiment 78 shown is a continuous trench, but in other embodiments, the trench may have interruptions or intervals or may be formed as a set of spaced openings set at a desired distance to produce the desired crack and delamination mitigation.

[0054] The various image sensor devices disclosed herein can be fabricated using various methods for forming image sensor packages. References Figure 6 A cross-sectional view is shown illustrating a specific implementation of the first stage in forming two image sensor devices 80 and 82. In this first stage, a wafer stack is shown comprising an image sensor die and a second die already bonded together, each die including a dielectric layer. Figure 6 The image shows a wafer stack after a patterned layer 84 has been formed thereon. The patterned layer can be formed using, as a non-limiting example, photolithography, screen printing, stencil printing, transfer printing, or another method capable of placing vias and trenches in desired locations. As shown, the patterned layer includes openings 86, 88 corresponding to the locations of the vias. The patterned layer also includes openings 90, 92 corresponding to the locations where trenches will be formed. The material of the patterned layer can be a material designed to protect the pixel array during etching and removable from the pixel array after or during etching. In some implementations, different removable materials can be used to protect the pixel array and any die pads to be used for electrical connections, while different non-removable materials (or permanent attachment materials) are used to form openings 86, 88, 90, 92. For example, because it may not be necessary to remove the patterned material around the vias and trenches, permanent attachment materials (such as polyimide, nitride, or oxide) can be used in such implementations. Where permanent attachment material requires etching to form openings therein, an additional patterning operation can be performed to form an additional patterned layer on top of the patterned layer 84 before etching the desired openings. This additional patterned layer is then removed after the etching process for openings 86, 88, 90, and 92.

[0055] refer to Figure 7 The image sensor devices 80 and 82 are shown at the second stage of the process. The second stage is shown in the formation through... Figure 6The wafer stack following the process of creating the through-silicon vias 94, 96 and trenches 98, 100. Because the patterned layer is designed to form the through-silicon vias 94, 96 and trenches 98, 100, they are formed simultaneously. In various specific embodiments, as a non-limiting example, the formation process can be etching, dry etching, wet etching, or laser action, or any other process capable of simultaneously forming the through-silicon vias and trenches in the material of the semiconductor substrate used in the image sensor dies 102, 104 and the second dies 106, 108. When the semiconductor substrate material is silicon, a deep reactive ion etching process can be used to form the through-silicon vias 94, 96 and trenches 98, 100. During the etching process, over-etching can be used, which can cause the ends 110, 112 of the trenches 98, 100 to extend deeper into the thickness of the second dies 106, 108, as previously described in this document. In alternative embodiments, through-silicon vias and trenches may not be formed simultaneously, but rather formed in the same process step using one or another of the methods described above (such as waterjet cutting or laser drilling).

[0056] refer to Figure 8 The image sensor devices 80 and 82 are shown at the third stage of the process. The third stage is shown after the removal of... Figure 7 The wafer stack following the patterned layer 84 is shown. As a non-limiting example, the removal process may include ashing, solvent stripping, washing, polishing, or any other removal process consistent with the material type. In the third stage, image sensor devices 80, 82 may be monomerized, followed by additional chip-level packaging processes to complete the process of forming them into an image sensor package. In other implementations, additional wafer-level processing may be employed to form additional structures on the image sensor devices in the third stage prior to monomerization, such as… Figures 9 to 10 As shown (discussed in further detail below). Additional wafer-level processing can prepare image sensor devices 80, 82 for additional chip-level packaging processes (e.g., glass attachment, wire bonding, molding, etc.), or complete or substantially complete wafer-level packaging for each image sensor device, followed by monomerization. In some implementations, additional wafer-level processing may include one or more wafer planarization processes prior to the formation of the color filter array and / or microlenses to help increase die strength.

[0057] refer to Figure 9 This illustrates an image sensor device 80, 82 in a fourth stage after the color filter arrays 114, 116 and microlens arrays 118, 120 are formed on the pixel array regions of the image sensor devices 80, 82. In some implementations, only microlenses may be formed and the color filter array may not be included. Note that... Figure 9Image sensor devices 80 and 82 have through-silicon vias 122 and 124 and trenches 126 and 128 that are free of material after the formation processes of color filter arrays 114 and 116 and microlenses 118 and 120. In this embodiment of the method, after the formation of microlenses, the material of the microlenses is not retained in the through-silicon vias 122 and 124 and trenches 126 and 128. One way to achieve this is to fill the through-silicon vias 122 and 124 and trenches 126 and 128 with a temporary material (such as a planarizing material) during the microlens formation process, and then remove the planarizing material after the microlens processing is completed. In such embodiments, the material of the microlenses never fills the trenches 126 and 128, thus keeping the trenches unfilled. In other implementations, planar materials may not be used, and the material of the microlens may fill or partially fill the grooves 126 and 128, but may be completely removed in the final processing step of the microlens process, thereby keeping the grooves 126 and 128 open.

[0058] In other specific implementations, such as Figure 10 As shown, in the fourth stage, image sensor devices 80, 82 include filled trenches 126, 128. In specific embodiments of this method, the process may include filling trenches 126, 128 with the material of microlens 130 or with a planarized material different from the material of microlens 130 during the microlens fabrication process. The microlens material or planarized material in trenches 126, 128 may act as stress protectors and / or prevent particle accumulation in the trenches, which could reduce their effectiveness. To achieve open through-silicon vias 122, 124, removable material may fill through-silicon vias 122, 124 while leaving trenches 126, 128 exposed prior to the microlens formation process. In alternative embodiments, filling trenches 126, 128 with microlens material or planarized material may occur in a separate process after microlens formation. Those skilled in the art can conceive of various method embodiments using the principles disclosed in this document.

[0059] Where specific embodiments of the image sensor package and implementation components, sub-components, methods and sub-methods are mentioned in the above description, it should be apparent that various modifications can be made without departing from the spirit of the invention, and that these embodiments, implementation components, sub-components, methods and sub-methods can be applied to other image sensor packages.

Claims

1. An image sensor package, the image sensor package comprising: An image sensor die, the image sensor die including a through hole and a groove, both the through hole and the groove being adjacent to a sealing ring; and A second die, the second die being bonded to the image sensor die by hybrid bonding, the second die including bonding pads; The through-hole extends into the thickness of the second die to reach the bonding pad; and The groove extends into the thickness of the second die.

2. The image sensor package according to claim 1, wherein the groove is located between the scribed area of ​​the image sensor die and the sealing ring.

3. The image sensor package of claim 1, wherein the trench is deeper than the through-hole extends into the thickness of the second die.

4. The image sensor package of claim 1, wherein the trench is unfilled.

5. The image sensor package of claim 1, wherein the trench is filled with either a microlens material or a planarizing material.

6. The image sensor package according to claim 1, wherein the image sensor die further includes a microlens array coupled to a color filter array, and the color filter array coupled to a pixel array.

7. The image sensor package of claim 1, wherein the trench extends beyond the corner of the image sensor die.

8. A method for forming an image sensor package, the method comprising: Provides image sensor die and second die; The image sensor die and the second die are hybrid bonded together; A patterned layer is formed on the pixel array included in the largest planar surface of the image sensor die; as well as Using the patterned layer, vias and trenches are simultaneously etched, wherein the trenches are adjacent to the sealing ring and extend through the thickness of the image sensor die and into the thickness of the second die.

9. The method of claim 8, further comprising: Remove the patterned layer and isolate the image sensor die and the second die adjacent to the trench.

10. The method of claim 9, further comprising: Monomerization is achieved using sawing.

11. The method according to claim 8, further comprising: The etching of the via is stopped at the bonding pad included in the second die.

12. The method according to claim 11, further comprising: An over-etching time is applied during the etching process to make the trench extend deeper than the through-hole through the thickness of the second die.

13. The method according to claim 8, further comprising: A color filter array is formed on the pixel array; as well as Microlenses are formed on the color filter array.

14. The method according to claim 8, further comprising: A color filter array is formed on the pixel array; Microlenses are formed on the color filter array using a microlens material; as well as While forming the microlens, the groove is filled with the microlens material.

15. The method according to claim 14, further comprising: Remove the microlens material from the groove.

16. The method according to claim 8, further comprising: A color filter array is formed on the pixel array; Microlenses are formed on the color filter array using a microlens material, without filling the grooves with the microlens material.

17. An image sensor package, the image sensor package comprising: Image sensor chip; The second die is bonded to the image sensor die by hybrid bonding; A through-hole, which extends into the thickness of the second die through the hybrid bonding; and The trench extends into the thickness of the second die via the hybrid bonding and extends around the periphery of the image sensor die.

18. The image sensor package of claim 17, wherein the groove is located between the scribe area of ​​the image sensor die and the sealing ring.

19. The image sensor package of claim 17, wherein the trench is unfilled.

20. The image sensor package of claim 17, wherein one of a microlens material or a planarizing material fills the trench.

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