Semiconductor device, optical receiver, and manufacturing method for photodetector

Abstract

A semiconductor device, an optical receiver, and a manufacturing method for a photodetector are disclosed. The semiconductor device comprises a photodetector die, and the photodetector die comprises a main body, a second electrode, and a protective layer. The main body comprises a first electrode, and the first electrode comprises a first surface. The second electrode is at least partially formed on the first surface of the first electrode, and the protective layer comprises a first part configured to at least partially cover the joint of the edge of the second electrode and the main body of the photodetector. The first part comprises a first opening to expose part of the area of the second electrode as a wire bonding area. According to the photodetector die structure of the semiconductor device, the isolation between a chip internal circuit and a chip wiring position and an external environment can be achieved, the stability of a wire bonding structure can be improved, the requirement of the automotive grade on the chip-level packaging process of a photodetector is reduced, and the packaging cost is reduced.

Description

Semiconductor device, optical receiver, and method for manufacturing photodetector Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and in particular to a method for manufacturing a semiconductor device, an optical receiver, and a photodetector. Background Art

[0002] Optical detection technology uses light as a medium to detect objects. It is finding applications in a growing number of fields, including intelligent driving, drones, robot recognition, geographic mapping, and environmental monitoring. During detection, a laser emits light. When the laser hits an object, it reflects off the surface, producing an echo. A photodetector receives the reflected echo and converts it into an electrical signal. This signal is processed to reveal information about the object, such as its distance, position, or velocity, as well as its three-dimensional structure.

[0003] The photodetector may be a semiconductor device, for example, a PIN photodiode (PINPD), an avalanche photodiode (APD), a single photon avalanche diode (SPAD), or a silicon photomultiplier (SiPM).

[0004] Currently, semiconductor devices such as photodetectors have the problem of high cost in optical detection applications. Summary of the Invention

[0005] The purpose of the present disclosure is to provide a method for manufacturing a semiconductor device, an optical receiver, and a photodetector, so as to reduce the cost of similar semiconductor devices such as photodetectors in optical detection applications.

[0006] In a first aspect, a semiconductor device is provided, comprising a photodetector die, the photodetector die comprising a main body, a second electrode and a protective layer: the main body comprises a first electrode, the first electrode comprises a first surface; the second electrode is at least partially formed on the first surface of the first electrode; the protective layer comprises a first portion, the first portion is configured to at least partially cover the junction of an edge of the second electrode and the main body of the photodetector, and the first portion comprises a first opening, the first opening exposes a partial area of ​​the second electrode as a bonding area.

[0007] Optionally, the protective layer includes an organic solid.

[0008] Optionally, the protective layer further includes a second portion, which is configured to be formed on the surface of the main body and includes an optical lens.

[0009] Optionally, the main body is formed with a groove, the first electrode is at least partially formed in the groove, the second electrode is at least partially formed in the groove and at least partially covers the first electrode; a portion of the protective layer is filled between the edge of the second electrode and the side wall of the groove.

[0010] Optionally, the photodetector die further includes a passivation layer, the passivation layer is configured to extend from the surface of the body to the first surface of the first electrode; the passivation layer includes a second opening, the second opening exposes a portion of the first surface for forming the second electrode.

[0011] Optionally, the second electrode at least partially covers the first electrode; and the first portion of the protective layer covers the junction between the edge of the second electrode and the main body.

[0012] Optionally, the first electrode includes an aluminum-based pad or a copper-based pad.

[0013] Optionally, the second electrode comprises a gold-based pad.

[0014] Optionally, the second electrode includes one or more of a nickel-palladium-gold electrode, a nickel-gold electrode, a copper-nickel-gold electrode, and a titanium-nickel-gold electrode.

[0015] Optionally, an isolation layer is formed between the first electrode and the second electrode.

[0016] Optionally, the photodetector die includes a single photon avalanche diode die or a silicon photomultiplier tube die.

[0017] Optionally, the semiconductor device includes a plurality of photodetector dies arranged in an array.

[0018] In a second aspect, an optical receiver is provided, comprising a carrier and a wiring pad; a semiconductor device according to any one of the first aspects, disposed on the carrier; and a wire connected between a bonding area of ​​the semiconductor device and the wiring pad.

[0019] In a third aspect, a method for manufacturing a photodetector die is provided, comprising:

[0020] forming a plurality of photodetector bodies on the surface of the wafer, wherein the photodetector bodies include a first electrode, and the first electrode includes a first surface;

[0021] growing a second electrode, wherein the second electrode is at least partially grown on the first surface of the first electrode;

[0022] growing a protective layer, the protective layer including a first portion, the first portion being configured to at least partially cover a junction of an edge of the second electrode and the first electrode or the photodetector body;

[0023] forming a first opening in the first portion of the protective layer to expose a portion of the second electrode as a bonding area;

[0024] The wafer is cut into a plurality of photodetector dies or at least one photodetector array.

[0025] Optionally, growing a protective layer includes: coating a protective material on the surface of the wafer;

[0026] Curing protective materials;

[0027] The first portion is formed by etching a portion of the protective material on the surface of the second electrode to form a first opening, and retaining a portion of the protective material at the junction of the edge of the second electrode and the photodetector body.

[0028] Optionally, the protective layer further includes a second part, which is configured to be formed on the surface of the photodetector body and includes an optical lens. Growing the protective layer also includes: preparing part of the protective material of the second part into an optical lens.

[0029] Optionally, the manufacturing method further includes: growing optical lens material, and preparing part of the optical lens material into an optical lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The following is an introduction to the drawings used in describing the embodiments of the present disclosure.

[0031] FIG1 shows a schematic structural diagram of an example semiconductor device provided by an embodiment of the present disclosure.

[0032] FIG2 shows a schematic structural diagram of another semiconductor device example provided by an embodiment of the present disclosure.

[0033] FIG3 shows a schematic structural diagram of another example of a semiconductor device provided by an embodiment of the present disclosure.

[0034] FIG4 shows a schematic structural diagram of another example of a semiconductor device provided by an embodiment of the present disclosure.

[0035] FIG5 shows a schematic structural diagram of another example of a semiconductor device provided by an embodiment of the present disclosure.

[0036] FIG6 shows a schematic structural diagram of another example of a semiconductor device provided by an embodiment of the present disclosure.

[0037] FIG7 shows a schematic structural diagram of another example of a semiconductor device provided by an embodiment of the present disclosure.

[0038] FIG8 is a schematic flow chart showing an example of a method for manufacturing a photodetector according to an embodiment of the present disclosure.

[0039] FIG9 is a schematic diagram showing an example of a manufacturing stage of an example photodetector provided by an embodiment of the present disclosure.

[0040] FIG10 is a schematic diagram showing another example of a manufacturing stage of an example photodetector provided by an embodiment of the present disclosure.

[0041] FIG11 is a schematic diagram showing another example of a manufacturing stage of an example photodetector provided by an embodiment of the present disclosure.

[0042] FIG12 is a schematic diagram showing an example of a manufacturing stage of another example of a photodetector provided by an embodiment of the present disclosure.

[0043] FIG13 is a schematic diagram showing another example of a photodetector at another manufacturing stage according to an embodiment of the present disclosure.

[0044] FIG. 14 is a schematic diagram showing another example of a manufacturing stage of another example of a photodetector provided by an embodiment of the present disclosure.

[0045] FIG15 is a schematic diagram showing an example of a manufacturing stage of yet another example of a photodetector provided by an embodiment of the present disclosure.

[0046] FIG16 is a schematic diagram showing another example of a manufacturing stage of yet another example of a photodetector provided by an embodiment of the present disclosure.

[0047] FIG17 shows a schematic structural diagram of an optical receiver example provided by an embodiment of the present disclosure.

[0048] FIG18 is a schematic structural diagram showing an example of a photodetector die. DETAILED DESCRIPTION

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the specific embodiments of the present disclosure will be described below with reference to the accompanying drawings. The drawings described below are only some embodiments of the present disclosure. For those skilled in the art, other drawings and other embodiments can be obtained based on these drawings without any creative work. Adjustments and improvements made without departing from the concept of the present disclosure are all within the scope of protection of the present disclosure.

[0050] To simplify the drawings, the drawings in the embodiments of the present disclosure schematically illustrate only the portions relevant to the corresponding embodiments and do not represent the actual structure of the products. Furthermore, to simplify the drawings and facilitate understanding, some drawings schematically depict (or label) only some structures or components; in practice, more or fewer identical or similar structures or components may exist.

[0051] In the embodiments shown in the drawings, the directions (such as up, down, left, right, front, and back) used in describing the various structures are not absolute but relative and are not used to limit the directions of the products in actual use.

[0052] In this disclosure, unless otherwise expressly specified or limited, ordinal numbers such as "first" and "second" are used solely to distinguish and describe related objects and are not to be construed as indicating or implying the relative importance or order of the related objects. Furthermore, they do not represent the quantity of the related objects. "And / or" is used to describe the relationship between related objects, including any relationship between the related objects. For example, "a and / or b" includes "a alone," "b alone," or "a and b."

[0053] Optical detection technology, which uses light as a medium to detect objects, is finding applications in a growing number of fields, including intelligent driving (such as assisted and autonomous driving), drones, robot recognition, geographic mapping, and environmental monitoring. For example, the application of LiDAR in intelligent driving: LiDAR is installed on vehicles to sense the surrounding environment and provide input for intelligent driving decision-making and control.

[0054] Compared to consumer-grade chips, automotive-grade chips have higher requirements for safety, reliability, operating environment, and design lifespan. For example, vehicles and other transportation vehicles operate in harsher environments. For example, the engine compartment temperature range is -40°C to 150°C. Furthermore, vehicles experience more vibration and impact while driving. Furthermore, the interior environment can be subject to high humidity, dust, or corrosion, among other conditions. Therefore, automotive chips operate in a wider temperature range, a more complex, and unstable environment. Furthermore, the service life of a vehicle is much longer than that of consumer electronics, for example, around 15 years or 200,000 kilometers, or even longer. Therefore, automotive chips have even higher long-term reliability requirements. Therefore, automotive-grade electronic products must meet more stringent quality standards. When used in automotive electronics, automotive-grade chips must undergo quality testing, such as the Automotive Electronics Council (AECQ) quality standard. AEC-Q100, a sub-standard of AECQ, provides a reliability testing standard applicable to integrated circuits.

[0055] When LiDAR is used in vehicles, the chips within it, such as photodetectors, need to be packaged to protect the die and meet automotive-grade requirements. For example, photodetector chips such as single-photon avalanche diodes (SPADs) and silicon photomultipliers (SiPMs) need to be packaged to protect the die before use in LiDAR.

[0056] Without the protection of a packaging structure, designs that directly apply photodetector bare chips are generally considered unable to meet automotive-grade requirements, such as failing to pass the Automotive Electronics Council qualification (AECQ) test.

[0057] In the application of photodetector bare chips, environmental hazards primarily manifest in the following aspects: damage to the connecting structures, such as wire bonds (also known as wire bonding structures, bonding structures, or wire bonding pads), caused by environmental exposure (e.g., moisture, corrosive gases, etc.); and damage to the chip's internal circuitry, such as damage caused by environmental exposure (e.g., moisture, corrosive gases, etc.). Therefore, packaging processes can be used to protect the chip's connecting and internal structures.

[0058] The packaging process of photosensitive chips (such as photodetector chips) adopts chip-scale packaging technology, which increases the complexity of the entire chip application process and has high packaging costs.

[0059] Taking the above issues into consideration, the disclosed embodiments design a wafer-level structure for a photosensitive die (e.g., a photodetector die). Within the semiconductor structure of the photodetector, an additional connection region (e.g., a second electrode) is provided at the connection region between the wire and the photodetector body (e.g., the first electrode of the photodetector). The junction between the second electrode and the photodetector body (excluding the electrical connection) is at least partially covered with a protective layer. This effectively isolates the chip's internal circuitry and the chip's wiring locations from the external environment, improves the stability of the wire bonding structure, reduces automotive regulations for the photodetector's chip-level packaging process, and thus reduces packaging costs.

[0060] The following description will be given with reference to the accompanying drawings.

[0061] Please refer to Figure 1, which shows a schematic diagram of the structure of an example semiconductor device provided by an embodiment of the present disclosure. As shown in Figure 1, the semiconductor device includes a photodetector die 100. The photodetector die 100 includes a photodetector body (hereinafter referred to as the body) 110 and a second electrode 120. The body 110 includes a first electrode 111, and the first electrode 111 includes a first surface S. The second electrode 120 is at least partially formed on the first surface S of the first electrode 111, and a portion of the second electrode 120 may be a bonding area.

[0062] The above-described semiconductor device directly utilizes a bare photodetector die, generating a second electrode on the first electrode originally intended for direct bonding. Bonding through the second electrode allows a wire to connect to the bonding area of ​​the second electrode, and thus to the first electrode. This allows for electrical connection between the bare photodetector die and other components without directly connecting the wires to the first electrode of the photodetector body. Furthermore, the first electrode need not be exposed, with the bonding area of ​​the second electrode exposed. This improves protection of the photodetector body and reduces environmental erosion (such as moisture and corrosive gases) on the chip's internal circuitry and the first electrode.

[0063] In some embodiments, the second electrode may be partially formed on the first surface of the first electrode. In other embodiments, the second electrode may be entirely formed on the first surface of the first electrode. For example, in the example shown in FIG1 , the second electrode 120 covers the first electrode 111, is partially formed on the first surface S, is partially formed on the side of the first electrode 111, and is in contact with the surface of the main body 110. The structure shown in FIG1 is only an example. In other embodiments, the second electrode may be entirely formed on the first surface of the first electrode; for example, please refer to FIG2 , which shows a schematic structural diagram of another semiconductor device example provided in an embodiment of the present disclosure. In the semiconductor device 200 shown in FIG2 , the second electrode 220 is entirely formed on the first surface S of the first electrode 111. In other embodiments, the second electrode may partially cover the first electrode; for example, please refer to FIG3 , which shows a schematic structural diagram of another semiconductor device example provided in an embodiment of the present disclosure. In the semiconductor device 300 shown in FIG3 , the second electrode 320 partially covers the first electrode 311 , and a gap is left between the second electrode 320 and the main body 310 . When the protective material is grown in a subsequent step, the gap between the second electrode 320 and the main body 310 is filled with the protective material.

[0064] In some embodiments of the present disclosure, the first electrode may include an aluminum-based pad or a copper-based pad. Taking the aluminum-based pad as an example, it may include a pure aluminum, aluminum alloy (for example, aluminum-silicon-copper, aluminum-copper, aluminum-silicon, etc.) pad. Aluminum alloys can be obtained by adding one or more materials such as copper and silicon to aluminum, and the content of copper and / or silicon added to aluminum varies from product to product, and the present disclosure does not limit this. For example, in the aluminum-silicon-copper pad, the silicon content is 0-1%, and the copper content is 0.25-2.5%, wherein when the silicon content is 0, the aluminum-silicon-copper pad is an aluminum-copper pad. For example, in the aluminum-silicon pad, the silicon content is 1-2%. For example, in the aluminum-copper pad, the copper content is 0.25-2.5%. The copper-based pad may include, for example, pure copper, a copper alloy pad (for example, other metal elements such as one or more of tin, nickel, zinc, etc. are added to pure copper), a copper-plated pad, or a copper-clad steel pad. The present disclosure does not limit the specific composition of the first electrode. The first electrode is used to connect the photodetector body to other components. For example, it can be prepared using a complementary metal oxide semiconductor (CMOS) fabrication process (Fab process). The present disclosure does not limit the shape of the first electrode. For example, the first electrode can be set in a rectangular shape and grown on the surface of the photodetector body; or it can be set in a cylindrical or truncated cone shape and grown on the surface of the photodetector body. In some embodiments, the surface of the body includes a plane. In other embodiments, the surface of the body includes a surface with a groove. For example, please refer to Figure 4, which shows a structural schematic diagram of another example of a semiconductor device provided by an embodiment of the present disclosure. The body 410 includes a groove C, and the first electrode 411 is formed on the surface of the groove C. The first electrode can be grown entirely on the surface of the photodetector body (as shown in Figures 1 to 4); or it can be partially placed inside the photodetector body and partially exposed on the surface of the photodetector body. For example, please refer to Figure 5, which shows a structural schematic diagram of another example of a semiconductor device provided by an embodiment of the present disclosure. The body 510 includes a groove C, the first electrode 511 is formed inside the body 510, and the first surface S is exposed to the body 510 through the groove C.

[0065] Refer to Figure 18, which shows a schematic diagram of the structure of an example photodetector die. When the wire 1830 connecting the photodetector die 1800 to other components is directly connected to the first electrode 1811 of the main body 1810, this bonding method, because the bonding point is exposed on the chip surface, can easily cause environmental corrosion into the chip interior. Corrosion of the first electrode can also cause instability in the connection.

[0066] The embodiment of the present disclosure additionally provides a second electrode, so that the second electrode is at least partially formed on the first surface of the first electrode, and a partial area of ​​the second electrode is used as a wiring area. The introduction of the second electrode can connect the wire to the wiring area of ​​the second electrode, and then electrically connect to the first electrode, so that the electrical connection between the photodetector die and other components can be achieved without the wiring being directly connected to the first electrode. In addition, the first electrode no longer needs to be exposed, and what is exposed is the wiring area of ​​the second electrode, so as to better protect the photodetector body and reduce the erosion of the external environment (such as moisture, corrosive gases, etc.) on the internal circuit of the chip and the first electrode. For automotive-grade applications, semiconductor devices face more complex, harsh, or long-term operating environments. The provision of the second electrode can reduce the possibility of the photodetector body being exposed to the operating environment, reduce the interference of the operating environment on the photodetector body, make the semiconductor device have better stability, and reduce the requirements of automotive regulations for the chip-level packaging process of the photodetector, thereby reducing the cost of packaging.

[0067] The embodiments of the present disclosure do not limit the specific location of the bonding area. For example, the bonding area can be set in the center of the surface of the second electrode away from the first electrode (for example, the top surface or the side surface); or the bonding area can be set to the left or right side of the surface of the second electrode away from the first electrode. The present disclosure does not limit the shape of the second electrode. The second electrode can be set on the surface of the first electrode, partially covering the first electrode. For example, the second electrode can be set to include a rectangular parallelepiped growing on the first surface of the first electrode; or it can be set to include a cylindrical or truncated cone growing on the first surface of the first electrode; or the second electrode can be set to include a cap shape that wraps at least the exposed portion of the first electrode, thereby protecting the first electrode.

[0068] For example, referring to FIG1 , the first electrode 111 is formed on the surface of the body 110, and the second electrode 120 covers the first electrode 111. For another example, in the semiconductor device 400 shown in FIG4 , the first electrode 411 is formed in the groove C of the body 410; the second electrode 420 covers the first electrode 411.

[0069] In wafer processing techniques (e.g., CMOS processes), a groove can be formed on the surface of the photodetector die when preparing the first electrode. In some embodiments of the present disclosure, the second electrode can also be partially formed within the groove and cover the first electrode. The provision of the groove can reduce the impact of the electrodes (e.g., the first electrode and / or the second electrode) on the chip thickness.

[0070] In some embodiments of the present disclosure, the second electrode can be a gold-based pad to improve the reliability of the bonding at the wire bonding point, improve the isolation effect from the external environment, and better protect the first electrode. Similarly, the wire connecting the photodetector die to other electronic components can include gold wire. The gold-based pad includes, for example, one or more of a nickel-palladium-gold electrode, a nickel-gold electrode, a copper-nickel-gold electrode, and a titanium-nickel-gold electrode. The gold-gold bond formed between the gold wire and the gold-based pad has a higher strength than the gold-aluminum bond, which can improve the connection strength between the pad and the gold wire. After the second electrode is introduced, the connection between the second electrode material and the wire is more stable and more resistant to interference from the external environment. AEC-Q100 includes multiple levels of standards divided by temperature range, among which the temperature range of Level 0 is, for example, -40°C to +150°C, the temperature range of Level 1 is, for example, -40°C to +125°C, the temperature range of Level 2 is, for example, -40°C to +105°C, and the temperature range of Level 4 is, for example, 0°C to +85°C. The second electrode can be a gold-based pad, and the conductive wire can include a gold wire. The gold-gold bond strength formed between the gold wire and the gold-based pad can meet the higher-level AEC-Q100 requirements. If the first electrode is directly connected to the conductive wire, the lower gold-aluminum bond strength may cause the connection between the first electrode and the conductive wire to become detached during high-temperature use or due to external contamination. The present disclosure does not limit the specific composition of the second electrode, and the selection can be based on the specifications and precision of the semiconductor device.

[0071] In some embodiments of the present disclosure, an isolation layer (or barrier layer) can be formed between the first electrode and the second electrode, so as to better adapt to the materials of the first electrode and the second electrode, reduce the mutual influence or reaction between the first electrode and the second electrode, and increase the connection strength.

[0072] In some embodiments of the present disclosure, the photodetector die 100 further includes a protective layer 130. The protective layer 130 includes a portion P1 (hereinafter referred to as a first portion for ease of description) that at least partially covers the junction of the edge of the second electrode 120 and the body 110. The first portion P1 has a first opening O1 that exposes a portion of the second electrode 120 for use as a bonding area. The present disclosure does not limit the size, shape, or position of the first opening, as long as it can subsequently be connected to an external wire.

[0073] The provision of the protective layer 130 can further enhance the isolation of the photodetector die from the environment. The present disclosure does not limit the specific coverage of the protective layer 130. The first portion P1 at least partially covering the junction between the edge of the second electrode 120 and the main body 110 may include: the first portion P1 covering the junction between the edge of the second electrode 120 and the main body 110; or, the first portion P1 partially covering the junction between the edge of the second electrode 120 and the main body 110. For example, in the example shown in FIG1 , the edge of the second electrode 120 is in contact with the surface of the main body 110, and the junction is shown as the portion circled by the dotted ellipse in FIG1 . The first portion P1 of the protective layer 130 covers the junction between the edge of the second electrode 120 and the main body 110. For another example, in the example shown in FIG2 , the edge of the second electrode 220 contacts the surface of the first electrode 111 of the body 110, and the first electrode 111 contacts the surface of the body 110, and the contact portion is shown in the dotted oval circle in FIG2 . The first portion P1 of the protective layer 230 covers the contact portion between the edge of the second electrode 120 and the first electrode 111, and the contact portion between the edge of the first electrode 111 and the surface of the body 110. For another example, in the example shown in FIG4 , the edge of the second electrode 420 contacts the surface of the body 410, and the contact portion is shown in the dotted oval circle in FIG4 . The first portion P1 of the protective layer 430 covers the contact portion between the edge of the second electrode 420 and the body 410. For another example, in the example shown in FIG5 , the edge of the second electrode 520 contacts the surface of the body 510, and the contact portion is shown in the dotted oval circle in FIG5 . The first portion P1 of the protective layer 530 covers the contact portion between the edge of the second electrode 520 and the body 510. For another example, in the example shown in Figure 3, the edge of the second electrode 320 is connected to the side of the first electrode 311, and the first electrode 311 is connected to the surface of the main body 310. The connection is shown in the part circled by the dotted ellipse in Figure 3. The first part P1 of the protective layer 330 covers the connection between the edge of the second electrode 320 and the first electrode 311, and covers the connection between the first electrode 311 and the surface of the main body 310.

[0074] By providing a protective layer, the edge of the second electrode and the interface with the photodetector body are protected by the protective layer, further isolating the die from the external environment (such as moisture or corrosive gases). In some embodiments, the second electrode and protective layer can enhance the reliability of the photodetector die in various environments, helping it meet automotive-grade requirements with simplified or no subsequent chip-scale packaging, thereby effectively reducing the cost of independent packaging.

[0075] In some embodiments of the present disclosure, the protective layer may include an organic solid. This not only isolates the chip from the external environment (such as moisture or corrosive gases) and prevents the external environment from corroding the internal circuitry of the chip, but also has good fluidity, enabling it to fill the gap between the edge of the second electrode and the photodetector body. The organic solid may include, for example, an organic polymer material such as resin.

[0076] In some embodiments of the present disclosure, the semiconductor device includes a photosensitive device, such as a photodetector, and an optical lens can be formed above the photosensitive area of ​​the photodetector by a semiconductor process, thereby improving the light detection efficiency. The optical lens can be made of the same or different material as the protective layer, for example, it can be made of an organic curing material (for example, a resin). In some embodiments, the protective layer can have both the functions of protection and optical lens. For example, the first portion P1 of the protective layer 130, 230, 330, 430 or 530 can at least partially cover the junction of the edge of the second electrode 120, 220, 320, 420 or 520 and the main body 110, 410 or 510; the second portion P2 of the protective layer 130, 230, 330, 430 or 530 can be formed on the surface of the main body 110, 410 or 510 and include an optical lens. In this way, when forming a protective layer on the photodetector body, a single protective layer can be formed, and then a portion of the protective layer (e.g., the protective layer on the pixel area) can be fabricated into an optical lens, achieving an integrated design of protection and optical lens, simplifying the process. In some embodiments, the protective layer can be formed separately from the optical lens, i.e., a separate protective layer is formed at the edge of the electrode, and a separate optical lens is formed above the pixel area. In this case, the photodetector die 100, 200, 300, 400, or 500 further includes a lens layer 140, 240, 340, 440, or 540, and the lens layer 140, 240, 340, 440, or 540 includes an optical lens. The lens layer 140, 240, 340, 440, or 540 and the protective layer 130, 230, 330, 430, or 530 can be made of the same or different materials.

[0077] The wafer-level processing techniques employed in the disclosed embodiments impose no restrictions on the shape or structure of the photodetector die. For example, the photodetector die can be planar or non-planar. Forming the lens structure at the wafer level reduces the requirements for subsequent chip-scale packaging, minimizing impact or damage to the already formed lens structure and ensuring device detection efficiency.

[0078] In some embodiments of the present disclosure, when the photodetector die is a planar structure, please refer to Figures 1 and 2. The first electrode 111 is formed on the surface of the main body 110; the second electrode 120 or 220 at least partially covers the first electrode 111; and the first portion P1 of the protective layer 130 or 230 at least partially covers the junction between the edge of the second electrode 120 or 220 and the main body 110.

[0079] In some embodiments of the present disclosure, when the photodetector die has a non-planar structure, referring to Figures 4 and 5 , a groove C is formed in the main body 410 or 510. The first electrode 411 or 511 is at least partially formed in the groove C. The second electrode 420 or 520 is at least partially formed in the groove and at least partially covers the first electrode 411 or 511. A first portion P1 of the protective layer 430 or 530 fills the space between the edge of the second electrode 420 or 520 and the sidewall of the groove C.

[0080] In some embodiments of the present disclosure, the photodetector die further includes a passivation layer, which can prevent corrosion to the interior of the chip by moisture, corrosive elements, etc. In some embodiments, the passivation layer can extend from the second surface of the photodetector body to the first surface of the first electrode, so that the passivation layer covers as much area of ​​the photodetector die as possible. The passivation layer includes a second opening, which exposes a portion of the first surface for forming the second electrode. When the second electrode is grown on the first surface of the first electrode, the edge of the second electrode can be in contact with the passivation layer, and the first portion of the protective layer covers the junction between the edge of the second electrode and the surface of the passivation layer. For example, the cross-sectional area of ​​the portion of the second electrode close to the surface of the photodetector body can be smaller than the cross-sectional area of ​​the portion away from the surface of the photodetector body. The bottom of the second electrode cooperates with the second opening so that the edge of the second electrode is in contact with the passivation layer. When the protective layer fills the gap between the second electrode and the passivation layer, the effect of isolating the chip from the external environment can be further improved. For example, as shown in FIG6 , the photodetector die 100 ′ further includes a passivation layer 150 extending from the surface of the body 110 to the first surface S of the first electrode 111 and including a second opening O2, through which the first surface S is exposed to the body 110. Similarly, the photodetector die 200 shown in FIG2 may also be further provided with a passivation layer. This passivation layer may have a similar position, and the second opening is used to expose the first surface. The second electrode may be formed within or cover the second opening. Similarly, the photodetector die 400 shown in FIG4 may also be further provided with a passivation layer. This passivation layer may have a similar position. As shown in FIG7 , the photodetector die 400 ′ further includes a passivation layer 450 extending from the surface of the body 410 to the first surface S of the first electrode 411 and including a second opening O2, through which the first surface S is exposed to the body 410. Similarly, the photodetector die 500 shown in FIG5 may also be further provided with a passivation layer 550. This passivation layer may have a similar position.

[0081] The passivation layer may include, for example, an oxide or oxynitride layer. During chip wafer fabrication, after the upper metal wiring is completed, an oxide or oxynitride layer may be deposited, and a window (e.g., second opening O2) may be opened at the pad (first electrode) to provide electrical isolation, moisture resistance, contamination resistance, and anti-static protection, thereby protecting the internal circuitry.

[0082] In some embodiments of the present disclosure, when photodetector dies are processed at the wafer level, multiple photodetector bodies can be processed simultaneously on the wafer, and then the wafer can be cut to obtain a finished semiconductor device, such as a photodetector die or a photodetector die array. The semiconductor device can include a single photodetector die or a plurality of photodetector dies arranged in an array. The arrayed photodetector dies can include photodetector dies arranged in multiple rows and columns, or photodetector dies arranged in a single row and multiple columns, or photodetector dies arranged in multiple rows and a single column.

[0083] The above processing method improves processing efficiency and can be used in applications (for example, automotive-grade applications) without subsequent chip-level packaging. The above processing process at least includes the formation of the second electrode and / or the formation of the protective layer.

[0084] A method for manufacturing a semiconductor device (eg, a photodetector) will be described below with reference to the accompanying drawings.

[0085] Please refer to Figure 8, which shows a flow chart of an example of a method for manufacturing a photodetector according to an embodiment of the present disclosure. As shown in Figure 8, the method includes at least the following steps:

[0086] S810: forming a plurality of photodetector bodies on a surface of the wafer, wherein the photodetector bodies include a first electrode, and the first electrode includes a first surface;

[0087] S820: growing a second electrode, where the second electrode is at least partially grown on the first surface of the first electrode;

[0088] S830: growing a protective layer, the protective layer including a first portion, the first portion being configured to at least partially cover a junction between an edge of the second electrode and the photodetector body;

[0089] S840: forming a first opening in the first portion of the protective layer to expose a portion of the second electrode as a bonding area;

[0090] S850: Cutting the wafer to form a plurality of photodetector dies or at least one photodetector die array.

[0091] The above-mentioned manufacturing method of the photodetector enables the design of the photodetector bare chip to be carried out at the wafer level. Compared with chip-level packaging, the method of the embodiment of the present disclosure can not only effectively reduce the corrosion of the external environment on the inside of the chip, so that the photodetector meets the automotive-grade requirements, but also reduce the packaging cost, which is conducive to improving the competitiveness of the product.

[0092] In some embodiments of the present disclosure, when growing the protective layer, a protective material can be coated on the surface of the wafer and cured; thereby forming a first portion of the protective layer. For example, a portion of the protective material on the surface of the second electrode is etched away by photolithography to form a first opening. A portion of the protective material is retained at the junction of the edge of the second electrode and the photodetector body, such that the retained protective material covers the junction of the edge of the second electrode and the photodetector body. The coating process may include, for example, spin coating, dip coating, or deposition.

[0093] In the process of growing the protective layer, in some embodiments, a protective material can be coated on the surface of the wafer to form an overall protective layer, and then part of the protective layer (the protective layer on the pixel area) is configured as an optical lens to achieve an integrated design of the protective layer and the optical lens, thereby simplifying the process flow. For example, the protective layer also includes a second part, and the second part can be formed on the surface of the photodetector body and includes an optical lens. And the process of growing the protective layer also includes: forming the second part. The formation process of the second part includes: preparing an optical lens on part of the protective material through etching and thermal reflow processes, and the part of the protective material is the protective material at the location of the optical lens. In other embodiments, a protective layer is formed at the edge of the electrode, and an optical lens is formed separately on the pixel area. For example, after the protective material is solidified and before etching, the optical lens material is grown, and the part of the optical lens material corresponding to the pixel area is prepared into an optical lens through a thermal reflow process.

[0094] The above manufacturing method will be described below with reference to the accompanying drawings, taking the structure of the semiconductor device shown in FIG. 1 as an example.

[0095] Please refer to Figure 9. A plurality of photodetector bodies are formed on the surface of the wafer. For ease of understanding, Figure 9 shows a photodetector body formed on the wafer, and the other photodetector bodies are similar. The photodetector body 110 includes a first electrode 111, and the first electrode 111 includes a first surface. The present disclosure does not limit other structures of the photodetector body. The other structures are the basic structures of the photodetector, such as PN junctions, intrinsic semiconductor layers (I layers), and / or N-type or P-type multiplication regions. The preparation process of the photodetector body 110 structure can be prepared using existing or future semiconductor processes, and the embodiments of the present disclosure are not related to the process. The first electrode 110 is grown on the surface of the body 110, for example, the first electrode is grown using a CMOS process. The first electrode 110 can be grown on the surface of the photodetector body 110, or can be partially embedded in the interior of the photodetector body 110.

[0096] Continuing with FIG10 , an optical lens material is grown on the surface of a wafer to form an optical lens 140, which may be a microlens (ML) structure. Growing the optical lens material may include growing an optical lens film, such as growing an ML film. A portion of the optical lens material is prepared into the optical lens 140. For example, the optical lens is prepared using a thermal reflow method. In the thermal reflow method, a columnar array structure is formed after photoresist exposure and development. The photoresist is heated to or above its Platonic transition temperature and then softened, forming a microlens array under the action of surface tension. For another example, a grayscale exposure method may be used to prepare the optical lens. A grayscale photolithography mask or a computer is used to control the laser beam or electron beam dose so that certain areas are blasted through and certain areas are partially exposed, thereby forming a microlens array with a 3D contour. The disclosed embodiments do not limit the preparation process of the optical lens.

[0097] Continuing with reference to FIG11 , a second electrode 120 is grown. The second electrode 120 is at least partially formed on the first surface S of the first electrode 111. The second electrode 120 shown in FIG11 wraps around the exposed portion of the first electrode 111. In other implementations, the second electrode 120 may also be arranged to partially cover the surface of the first electrode 111. Optionally, during the growth or preparation of the second electrode 120, an isolation layer (or barrier layer) may be formed on the first surface S of the first electrode 111, and then the second electrode 120 may be formed on the isolation layer. For example, during the growth or preparation of the second electrode, the surface of the first electrode may be cleaned first, and then the isolation layer may be deposited, and the second electrode may be grown using a deposition, electroplating, or chemical plating process. For example, if the first electrode is an aluminum-based pad and the second electrode is a gold-based pad, a gold-based pad is prepared on the aluminum-based pad. No gold-based pad will grow in the non-aluminum-based pad area, and the growth of the gold-based pad will not affect the chip surface. Gold-based pads can improve the reliability of bonding between wires and chip pads, and protect aluminum-based pads from corrosion by moisture or corrosive elements.

[0098] 1 , a protective layer 130 is grown. The protective layer 130 at least partially covers the junction between the edge of the second electrode 120 and the photodetector body 110 and has a first opening O1 for exposing a portion of the surface of the second electrode 120 as a bonding area.

[0099] The growth process of the protective layer 130 includes, for example, spin-coating a protective material (e.g., a polyimide (PI) material) on the wafer surface and curing the protective material. Forming the first portion of the protective layer 130 includes etching away a portion of the protective material on the surface of the second electrode to form a first opening O1, while retaining a portion of the protective material at the junction of the edge of the second electrode 120 and the photodetector body 110, such that the retained portion of the protective material covers the junction of the edge of the second electrode and the photodetector body.

[0100] Through the protection of the protective layer 130 and the second electrode 120, the external environment is unable to invade the interior of the chip or the area where the first electrode 110 is located, and the gap is isolated, so that the photodetector bare chip 100 can still meet the automotive-grade requirements without subsequent packaging, which is conducive to reducing costs.

[0101] In some embodiments, the optical lens 140 is prepared before the second electrode 120 to reduce the impact of the height of the second electrode 120 on the preparation process of the optical lens 140. The second electrode can be prepared by electroplating to reduce possible damage to the optical lens 140 caused by the preparation process of the second electrode.

[0102] In the above embodiments, the optical lens 140 and the protective layer 130 are prepared independently, and the materials of the optical lens 140 and the protective layer 130 can be the same or different. A protective layer is formed at the edge of the second electrode, and an optical lens is formed separately on the pixel area. In other embodiments, the materials of the optical lens 140 and the protective layer 130 can be the same, and can be prepared in an integrated process, for example, a protective material is coated on the surface of the wafer, and the protective material is solidified to form an overall protective layer, and then part of the protective layer (for example, the protective layer on the pixel area) is formed into an optical lens; for example, the protective layer also includes: a second part. Forming the second part includes: preparing part of the protective material into an optical lens, and the part of the protective material is the protective material at the location where the optical lens is located.

[0103] The manufacturing process of the photodetector die shown in FIG. 2 or FIG. 6 is similar to the above process.

[0104] The above manufacturing method will be described below with reference to the accompanying drawings, taking the structure of the semiconductor device shown in FIG. 5 as an example.

[0105] First, referring to FIG. 12 , multiple photodetector bodies are formed on the surface of a wafer. For ease of understanding, FIG. 12 illustrates one photodetector body; the other photodetector bodies are similar. The photodetector body 510 includes a first electrode 511 , which includes a first surface S. In this embodiment, the photodetector die 500 has a non-planar structure. A groove C is formed on the surface of the photodetector die 500 , and the first electrode 511 is at least partially formed within the groove C. The present disclosure does not limit the specific location of the first electrode 511 within the groove C. For example, the first electrode 511 may be disposed at the bottom of the groove C and partially located within the photodetector die 500 (as shown in FIG. 5 ), or may be disposed on the surface of the bottom of the groove C (as shown in FIG. 4 ). Furthermore, the photodetector body 510 also includes a passivation layer 550 . The remaining description of the photodetector body is the same as in the above embodiment.

[0106] Continuing with FIG13 , a second electrode 520 is grown. The second electrode 520 is at least partially formed within the groove C and at least partially covers the first electrode 510 . The shape of the second electrode 520 within the groove C is not limited and the second electrode 520 may be entirely or partially located within the groove C. The rest of the description regarding the second electrode is the same as in the above embodiment.

[0107] Continuing with FIG. 14 , a protective layer 530 is grown. A first portion P1 of the protective layer 530 may at least partially cover the junction between the edge of the second electrode 520 and the photodetector body 510. For example, the first portion of the protective layer 530 fills the space between the edge of the second electrode 520 and the sidewall of the groove C. In other words, the first portion P2 of the protective layer 530 fills the space or gap between the side surface of the second electrode 520 and the sidewall of the groove C. The first portion P2 of the protective layer 530 may be formed on the surface of the photodetector body 510 and include an optical lens.

[0108] During this preparation process, the second electrode 520 is formed in the groove, so that its height has little or no effect on the preparation of the optical lens. During the preparation of the protective layer 530, part of the protective layer can be configured as an optical lens, realizing an integrated design of protection and optical lens, simplifying the process flow. When preparing the optical lens, the second electrode can be formed first, and then the optical lens is prepared. In this way, the formation process of the second electrode will not affect or damage the optical lens. In some other embodiments, the protective layer 530 and the optical lens can also be prepared separately.

[0109] For example, referring to Figures 15 and 16 , differences from the above embodiments include growing a lens layer 540 before growing the second electrode 520, and then forming a portion of the lens layer 540 into an optical lens 541 (as shown in Figure 15 ). Next, a second electrode 570 is grown, with the edge of the second electrode 570 contacting the lens layer 560 and thereby indirectly contacting the body 510 (as shown in Figure 16 ). Afterwards, a protective layer 580 is grown. The growth of the second electrode 570 and protective layer 580 is similar to that described in the above embodiments.

[0110] The manufacturing process of the photodetector die shown in FIG. 4 or FIG. 7 is similar to the above process.

[0111] In some embodiments of the present disclosure, please refer to FIG17 , which shows a schematic diagram of the structure of an example optical receiver provided by an embodiment of the present disclosure. As shown in FIG17 , the optical receiver 1700 includes a carrier 1710 and a semiconductor device 1720, wherein the semiconductor device is disposed on the carrier 1710. The carrier 1710 includes a wiring pad 1711, and a wire 1730 connects the wiring area of ​​the semiconductor device 1720 (e.g., located on the second electrode 1722) to the wiring pad 1711. That is, the wire 1730 is connected between the wiring area of ​​the semiconductor device 1720 and the wiring pad 1711. The carrier may include, for example, a circuit board or other chip-carrying structure.

[0112] The semiconductor device disclosed in the present invention can be used in an optical receiver. When in use, after the processed photodetector die is mounted on a carrier, the exposed bonding area of ​​the second electrode is connected to the wiring pad on the carrier by bonding to achieve electrical access to the semiconductor device on the carrier. The optical receiver can be used in various optical detection devices, such as laser radar. Compared with the photodetector die shown in Figure 18, the embodiment of the present invention generates a second electrode on the first electrode of the photodetector die, forms a protective layer at the junction of the edge of the second electrode and the photodetection body, and provides an opening on the protective layer to expose a portion of the second electrode as a bonding area. This can achieve isolation between the chip interior and the chip wiring position and the external environment, prevent damage to the chip by the external environment (such as water vapor, or corrosive gas, etc.), thereby reducing the requirements of the automotive regulations for the chip-level packaging process of the photodetector, making the optical receiver and the laser radar and other optical detection devices containing the optical receiver lower in cost. The processing of the photodetector die in the embodiment of the present invention can be completed at the wafer level, which is easier to implement and has lower cost than the more complex chip-level packaging.

[0113] In the above embodiments, the descriptions of each embodiment have their own emphasis. For parts that are not described or recorded in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. In addition, the above embodiments can be freely combined as needed. The above only shows some implementation methods of the present disclosure. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present disclosure. These improvements and modifications should also be considered as the scope of protection of the present disclosure.

Claims

1. A semiconductor device, characterized in that: comprising a photodetector die, the photodetector die comprising a body, a second electrode, and a protective layer; The body includes a first electrode, the first electrode including a first surface; The second electrode is at least partially formed on the first surface of the first electrode; The protection layer includes a first portion configured to at least partially cover a junction between an edge of the second electrode and the body of the photodetector, and the first portion includes a first opening exposing a portion of the second electrode as a bonding area.

2. The semiconductor device according to claim 1, wherein The protective layer further comprises: The second portion is configured to be formed on a surface of the main body and includes an optical lens.

3. The semiconductor device according to claim 1 or 2, wherein: The protective layer includes an organic cured material.

4. The semiconductor device according to any one of claims 1 to 3, wherein: The main body is formed with a groove, and the first electrode is at least partially formed in the groove; The second electrode is at least partially formed in the groove and at least partially covers the first electrode; The first portion of the protection layer is filled between the edge of the second electrode and the sidewall of the groove.

5. The semiconductor device according to any one of claims 1 to 3, wherein: The first electrode is formed on the surface of the body; The second electrode at least partially covers the first electrode; The first portion of the protection layer at least partially covers the junction between the edge of the second electrode and the main body.

6. The semiconductor device according to claim 4 or 5, characterized in that The second electrode covers the first electrode; and the first portion of the protection layer covers the junction between the edge of the second electrode and the main body.

7. The semiconductor device according to any one of claims 4 to 6, characterized in that: The photodetector die further includes a passivation layer configured to extend from the second surface of the body to the first surface of the first electrode; The passivation layer includes a second opening, and the second opening exposes a portion of the first surface for forming the second electrode.

8. The semiconductor device according to any one of claims 1 to 7, wherein: The first electrode includes an aluminum-based pad or a copper-based pad.

9. The semiconductor device according to any one of claims 1 to 8, wherein: The second electrode includes a gold-based pad. 10 . The semiconductor device according to claim 9 , wherein the second electrode comprises one or more of a nickel-palladium-gold electrode, a nickel-gold electrode, a copper-nickel-gold electrode, and a titanium-nickel-gold electrode.

11. The semiconductor device according to any one of claims 1 to 10, wherein: An isolation layer is formed between the first electrode and the second electrode.

12. The semiconductor device according to any one of claims 1 to 11, wherein: The photodetector die includes a single photon avalanche diode die or a silicon photomultiplier tube die.

13. The semiconductor device according to any one of claims 1 to 12, wherein: The semiconductor device includes a plurality of the photodetector dies arranged in an array.

14. An optical receiver, characterized in that: include: a carrier including a wiring tray; The semiconductor device according to any one of claims 1 to 13, arranged on the carrier, A wire is connected between the bonding area of ​​the semiconductor device and the wiring pad.

15. A method for manufacturing a photodetector, characterized in that: include: forming a plurality of photodetector bodies on a surface of the wafer, wherein the photodetector bodies include a first electrode, and the first electrode includes a first surface; growing a second electrode, wherein the second electrode is at least partially grown on the first surface of the first electrode; growing a protective layer, the protective layer comprising a first portion, the first portion being configured to at least partially cover a junction of an edge of the second electrode and the photodetector body; forming a first opening in the first portion of the protective layer to expose a portion of the second electrode as a bonding area; The wafer is cut into a plurality of photodetector dies or at least one photodetector array.

16. The manufacturing method according to claim 15, characterized in that: The growth protection layer comprises: coating a protective material on the surface of the wafer; curing the protective material; Forming the first portion includes: etching a portion of the protective material on the surface of the second electrode to form the first opening, and retaining a portion of the protective material at the junction of the edge of the second electrode and the photodetector body.

17. The manufacturing method according to claim 16, characterized in that: The protective layer further includes a second portion, the second portion being configured to be formed on a surface of the photodetector body and including an optical lens, and the growth protective layer further includes: Part of the second portion of the protective material is prepared into an optical lens.

18. The manufacturing method according to claim 16, characterized in that: Also includes: growing optical lens materials; Part of the optical lens material is prepared into an optical lens.

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