A packaging structure
Patent Information
- Application Number
- CN202521552953.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-23
- Publication Date
- 2026-08-18
- Estimated Expiration
- 2035-07-23
AI Technical Summary
[0004]有鉴于此，本实用新型的目的在于提供一种封装结构，用于解决现有技术中存在的封装厚度大、散热性能差、可靠性低、成本高的问题
[0021] 1. Small package thickness: This package structure mainly relies on a glass substrate, on which a redistribution layer is made. By expanding the redistribution layer outward, the thickness of this package structure is equivalent to the original thickness of the wafer material of the optoelectronic sensor chip, which is much smaller than the thickness of the traditional iBGA package structure (about 1800μm). This effectively reduces the package volume, thus better meeting the high-density requirements for optomechanical space and volume.
Smart Images
Figure CN224653901U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of semiconductor technology, and in particular to a packaging structure. Background Technology
[0002] The traditional iBGA (Image sensor Ball Grid Array, an advanced packaging technology for image sensor chips) packaging structure mounts the photoelectric sensor chip on the surface of a resin encapsulation substrate, connects the pads of the photoelectric sensor chip to the pads of the resin encapsulation substrate through gold wires, and finally places a glass substrate on top of the photoelectric sensor chip to encapsulate the photosensitive area on the surface of the photoelectric sensor chip.
[0003] In this packaging structure, a packaging substrate is placed below the photoelectric sensor chip, and a glass substrate is placed above it, resulting in a large packaging thickness (approximately 1800 μm). The photoelectric sensor chip is encapsulated between the packaging substrate and the glass substrate, preventing heat dissipation and leading to poor heat dissipation performance. The packaging structure is prone to warping due to heat accumulation, significantly increasing the risk of reliability failure and resulting in low reliability. For example, lidar chips generate more heat during operation than other photoelectric sensor chips, which dissipates onto the substrate, creating significant internal stress and causing severe warping, further complicating the packaging process. The use of high-reliability precious metals for the electrical connections of the pads results in high costs due to the large amount of precious metals used. The complex packaging method and steps also contribute to high packaging costs. Therefore, a packaging structure is needed to address the problems of large packaging thickness, poor heat dissipation, low reliability, and high cost in existing technologies. Utility Model Content
[0004] In view of this, the purpose of this utility model is to provide a packaging structure to solve the problems of large packaging thickness, poor heat dissipation performance, low reliability and high cost in the prior art.
[0005] To solve the above-mentioned technical problems, this utility model provides a packaging structure, including: a photoelectric sensor chip and a glass substrate;
[0006] The upper surface of the photoelectric sensing chip is provided with a photosensitive area and at least two first pads surrounding the photosensitive area; the surface of the first pads is provided with conductive bumps.
[0007] The glass substrate is disposed above the upper surface of the photoelectric sensing chip; a redistribution layer is disposed on the lower surface of the glass substrate; the redistribution layer includes at least two second pads surrounding the photosensitive area; and solder balls electrically contacting the second pads are also disposed on the glass substrate.
[0008] The photoelectric sensing chip is electrically connected to the solder ball through the conductive bump and the second pad.
[0009] Optionally, an anti-glare film is disposed between the glass substrate and the redistribution layer, and the anti-glare film is located above the non-photosensitive area of the photoelectric sensor chip.
[0010] Optionally, a buffer layer is provided between the glass substrate and the redistribution layer.
[0011] Optionally, a solder mask layer is provided on the lower surface of the redistribution layer.
[0012] Optionally, the thickness of the glass substrate is 300μm-800μm, including the values at both ends.
[0013] Optionally, the number of rewiring layers is 1 to 4, and includes the values at both ends.
[0014] Optionally, the conductive bumps include gold bumps;
[0015] And / or, the height of the conductive bump is 10μm-25μm, including the values at both ends.
[0016] Optionally, the solder balls include tin balls.
[0017] Optionally, the thickness of the encapsulation structure is less than 900 μm.
[0018] Optionally, the gap between the photoelectric sensing chip and the glass substrate is filled with sealant, and the sealant covers all the conductive bumps;
[0019] The glass substrate, the photoelectric sensing chip, and the sealant enclose a sealed cavity; the photosensitive area is located within the sealed cavity.
[0020] As can be seen, the packaging structure provided by this utility model has the following advantages compared with the traditional iBGA packaging structure:
[0021] 1. Small package thickness: This package structure mainly relies on a glass substrate, on which a redistribution layer is made. By expanding the redistribution layer outward, the thickness of this package structure is equivalent to the original thickness of the wafer material of the optoelectronic sensor chip, which is much smaller than the thickness of the traditional iBGA package structure (about 1800μm). This effectively reduces the package volume, thus better meeting the high-density requirements for optomechanical space and volume.
[0022] 2. Excellent heat dissipation performance: Both this packaging structure and the traditional iBGA packaging structure enclose the photoelectric sensor chip in the packaging structure. However, this packaging structure directly exposes the back of the photoelectric sensor chip. The heat generated by the photoelectric sensor chip during operation can be dissipated directly through the back of the photoelectric sensor chip. The heat dissipation effect is much better than that of the traditional iBGA packaging structure.
[0023] 3. High reliability: This packaging structure uses a glass substrate as the packaging carrier. The thermal expansion coefficient of the glass substrate is extremely similar to that of the photoelectric sensor chip, which can reduce the warping problem caused by heat accumulation in the packaging structure and greatly reduce the risk of reliability failure. The smaller thermal expansion coefficient and warping of the glass substrate can meet more stringent reliability conditions and is suitable for high-end applications such as automobiles.
[0024] 4. Low cost: This packaging structure uses a glass substrate combined with a redistribution layer for wiring. Compared with traditional resin packaging substrates, the process is simpler and the cost of the glass substrate is lower, up to 50%. Replacing the traditional gold wires with redistribution layer wiring reduces the use of precious metals, further reducing costs. The glass substrate packaging method and fewer packaging steps also effectively reduce packaging costs. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0026] Figure 1 This is a schematic diagram of a packaging structure provided in an embodiment of the present utility model.
[0027] The annotations in the attached figures are explained as follows:
[0028] 1-Glass substrate; 2-Sealant; 3-Matte film; 4-Buffer layer; 5-Reconnection layer; 6-Solder resist layer; 7-Solder ball; 8-Conductive bump; 9-Photoelectric sensor chip; 91-First pad; 92-Photosensitive area; 93-Substrate. Detailed Implementation
[0029] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0030] Please refer to Figure 1 , Figure 1 This is a schematic diagram of a packaging structure provided in an embodiment of the present invention. The packaging structure may include: a photoelectric sensor chip 9 and a glass substrate 1;
[0031] The upper surface of the photoelectric sensor chip 9 is provided with a photosensitive area 92 and at least two first pads 91 surrounding the photosensitive area 92; the surface of the first pads 91 is provided with conductive bumps 8.
[0032] A glass substrate 1 is disposed above the upper surface of the photoelectric sensor chip 9; a redistribution layer 5 is disposed on the lower surface of the glass substrate 1; the redistribution layer 5 includes at least two second pads surrounding the photosensitive area 92; and solder balls 7 that are electrically in contact with the second pads are also disposed on the glass substrate 1.
[0033] The photoelectric sensor chip 9 is electrically connected to the solder ball 7 via the conductive bump 8 and the second pad.
[0034] It should be noted that this embodiment can be applied to any type of photoelectric sensor chip 9, including, but not limited to, SPAD (Single-Photon Avalanche Diode) lidar chips. The photoelectric sensor chip 9 in this embodiment includes a substrate 93, a photosensitive area 92 disposed on the upper surface of the substrate 93, and at least two first pads 91 surrounding the photosensitive area 92; wherein the substrate 93 can be, but is not limited to, a silicon substrate. Silicon is a common material in the prior art, and this embodiment does not limit the internal composition of the substrate 93, but directly uses a silicon substrate made of existing materials.
[0035] This embodiment does not limit the specific number of the first pad 91, which can be determined according to the actual needs of the product. It should be noted that in this embodiment, one end of the conductive bump 8 is in electrical contact with the first pad 91, and the other end is in electrical contact with the second pad. The second pad in electrical contact with the solder ball 7 is located on the side of the second pad in electrical contact with the conductive bump 8 that is away from the photosensitive area 92. The conductive bump 8 can be soldered to the second pad to achieve electrical contact.
[0036] This embodiment does not limit the specific shape of the conductive bump 8, as long as it can ensure that the electrical connection between the first pad 91 and the second pad can be achieved.
[0037] This embodiment does not limit the specific number of conductive bumps 8; the number of conductive bumps 8 is the same as the number of first pads 91.
[0038] This embodiment does not limit the specific type of conductive bump 8, as long as it can conduct electricity. For example, the conductive bump 8 may include gold bumps. It should be noted that gold is a common material in the prior art. This embodiment does not limit the internal composition of the conductive bump 8, but directly uses gold bumps made of existing materials.
[0039] This embodiment does not limit the specific height of the conductive bump 8, which can be determined according to the actual needs of the product. For example, the height of the conductive bump 8 can be 10μm-25μm, including the values at both ends.
[0040] It should be noted that in this embodiment, the use of glass substrate 1 can prevent dust, moisture, and direct external contact from contaminating the photosensitive area 92 of the photoelectric sensor chip 9, both during the packaging process and in the module manufacturing after packaging. Glass substrate 1 provides strong support and enhances processing strength during packaging, while also achieving a light transmittance of over 98%, meeting the detection requirements.
[0041] This embodiment does not limit the specific thickness of the glass substrate 1, which can be determined according to the actual needs of the product. For example, the thickness of the glass substrate 1 can be 300μm-800μm, including the values at both ends.
[0042] It should be noted that the thickness of the packaging structure in this embodiment can be less than 900μm, which is much smaller than the thickness of the traditional iBGA packaging structure (approximately 1800μm).
[0043] It should be noted that, in this embodiment, the redistribution layer 5 refers to all conductive lines disposed on the lower surface of the glass substrate 1. This embodiment does not limit the specific type of conductive lines, as long as they are conductive; for example, conductive lines can be metal lines. It should be noted that metal is a common material in the prior art, and this embodiment does not limit the internal composition of the conductive lines, but directly uses metal lines made of existing materials.
[0044] This embodiment does not limit the specific number of redistribution layers 5. It can be determined according to the actual needs of the product. For example, the number of redistribution layers 5 can be 1 to 4 layers, including the values at both ends.
[0045] This embodiment does not limit the specific number of the second pads, which can be determined based on the specific number of conductive bumps 8 and solder balls 7.
[0046] This embodiment does not limit the specific number of solder balls 7, which can be determined according to the actual needs of the product.
[0047] This embodiment does not limit the specific type of solder ball 7, as long as it can simultaneously achieve electrical and soldering connections with other external devices. For example, solder ball 7 may include tin balls. It should be noted that tin is a common material in the prior art, and this embodiment does not limit the internal composition of solder ball 7, but directly uses tin balls made of existing materials.
[0048] Furthermore, in this embodiment, an anti-glare film 3 may be disposed between the glass substrate 1 and the redistribution layer 5, and the anti-glare film 3 is located above the non-photosensitive area 92 of the photoelectric sensor chip 9. It should be noted that in this embodiment, the anti-glare film 3 can dissipate stray light in the packaging structure.
[0049] Furthermore, in this embodiment, a buffer layer 4 may be provided between the glass substrate 1 and the redistribution layer 5. It should be noted that in this embodiment, providing the buffer layer 4 can alleviate the stress between the redistribution layer 5 and the glass substrate 1 or the matte film 3.
[0050] Furthermore, in this embodiment, a solder mask layer 6 may be provided on the lower surface of the redistribution layer 5. It should be noted that, in this embodiment, the solder mask layer 6 has through-holes to expose the second pads. The solder mask layer 6 in this embodiment can prevent the redistribution layer 5 from being corroded.
[0051] Furthermore, in this embodiment, the gap between the photoelectric sensor chip 9 and the glass substrate 1 can be filled with sealant 2, which covers all the conductive bumps 8; the glass substrate 1, the photoelectric sensor chip 9, and the sealant 2 enclose a sealed cavity; the photosensitive area 92 is located within the sealed cavity. It should be noted that in this embodiment, the sealant 2 can improve the overall bonding strength. By using the glass substrate 1 instead of the traditional resin encapsulation substrate and directly bonding it to the photoelectric sensor chip 9, and completing the overall sealing and bonding by applying sealant around the photoelectric sensor chip 9, the photosensitive area 92 can form a sealed cavity, and the encapsulation structure can achieve a thinner and lighter effect.
[0052] This embodiment does not limit the specific type of sealant 2, as long as adhesion can be achieved. For example, sealant 2 may include underfill adhesive. It should be noted that underfill adhesive is a common material in the prior art. This embodiment does not limit the internal components of sealant 2, but directly uses underfill adhesive made of existing materials.
[0053] Based on the above embodiments, compared with the traditional iBGA packaging structure, the present invention has the following advantages:
[0054] 1. Small package thickness: This package structure mainly relies on a glass substrate, on which a redistribution layer is made. By expanding the redistribution layer outward, the thickness of this package structure is equivalent to the original thickness of the wafer material of the optoelectronic sensor chip, which is much smaller than the thickness of the traditional iBGA package structure (about 1800μm). This effectively reduces the package volume, thus better meeting the high-density requirements for optomechanical space and volume.
[0055] 2. Excellent heat dissipation performance: Both this packaging structure and the traditional iBGA packaging structure enclose the photoelectric sensor chip in the packaging structure. However, this packaging structure directly exposes the back of the photoelectric sensor chip. The heat generated by the photoelectric sensor chip during operation can be dissipated directly through the back of the photoelectric sensor chip. The heat dissipation effect is much better than that of the traditional iBGA packaging structure.
[0056] 3. High reliability: This packaging structure uses a glass substrate as the packaging carrier. The thermal expansion coefficient of the glass substrate is extremely similar to that of the photoelectric sensor chip, which can reduce the warping problem caused by heat accumulation in the packaging structure and greatly reduce the risk of reliability failure. The smaller thermal expansion coefficient and warping of the glass substrate can meet more stringent reliability conditions and is suitable for high-end applications such as automobiles.
[0057] 4. Low cost: This packaging structure uses a glass substrate combined with a redistribution layer for wiring. Compared with traditional resin packaging substrates, the process is simpler and the cost of the glass substrate is 50% lower. Replacing the traditional gold wires with redistribution layer wiring reduces the use of precious metals, further reducing costs. The glass substrate packaging method and fewer packaging steps also effectively reduce packaging costs.
[0058] To facilitate understanding of this invention, this embodiment also provides a method for preparing a packaging structure. This method employs glass substrate 1 packaging technology and may specifically include:
[0059] Step 1: Apply matting film 3, buffer layer 4, redistribution layer 5 and solder resist layer 6 on a high-reflection glass substrate 1. The thickness of the glass substrate 1 can be selected from 300μm to 800μm, and the number of redistribution layers 5 can be selected from 1 to 4. Lead out the first pad 91 at the relative position of each pad area of the photoelectric sensor chip 9 to prepare for flip-chip bonding.
[0060] The second step is to create a conductive bump 8 (gold bump optional) on the first pad 91. The height of the conductive bump 8 can be selected from 10μm to 25μm.
[0061] The third step is to solder the photoelectric sensor chip 9 with conductive bumps 8 to the second pad in the redistribution layer 5 on the surface of the glass substrate 1. The conductive bumps 8 and the second pad are soldered by flip-chip thermoforming, thus completing the I / O (Input / Output) lead-out.
[0062] Step 4: Apply sealant 2 (optional bottom filler) to the gap between the photoelectric sensor chip 9 and the glass substrate 1 by dispensing around the flip-mounted photoelectric sensor chip 9, covering all the conductive bumps 8 to improve the overall bonding strength between the photoelectric sensor chip 9 and the glass substrate 1.
[0063] Step 5: Perform ball placement on the second pad in the redistribution layer 5 to complete the fabrication of SMT (Surface Mount Technology) solder balls 7 (optional solder balls). At this point, each I / O of the optoelectronic sensing wafer is connected and made conductive to each solder ball 7 through the redistribution layer process.
[0064] Step 6: After completing the relevant processes, the glass substrate 1 is cut to form a package structure of a single photoelectric sensor chip 9.
[0065] The above-mentioned packaging structure can be prepared by applying the preparation method of the packaging structure provided in the embodiments of this utility model.
[0066] The above provides a detailed description of the packaging structure provided by this utility model. For those skilled in the art, based on the ideas of the embodiments of this utility model, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this utility model.
Claims
1. A packaging structure, characterized in that, include: Optoelectronic sensor chips and glass substrates; The upper surface of the photoelectric sensing chip is provided with a photosensitive area and at least two first pads surrounding the photosensitive area; the surface of the first pads is provided with conductive bumps. The glass substrate is disposed above the upper surface of the photoelectric sensing chip; a redistribution layer is disposed on the lower surface of the glass substrate; the redistribution layer includes at least two second pads surrounding the photosensitive area; and solder balls electrically contacting the second pads are also disposed on the glass substrate. The photoelectric sensing chip is electrically connected to the solder ball through the conductive bump and the second pad.
2. The packaging structure according to claim 1, characterized in that, An anti-glare film is disposed between the glass substrate and the redistribution layer, and the anti-glare film is located above the non-photosensitive area of the photoelectric sensor chip.
3. The packaging structure according to claim 1, characterized in that, A buffer layer is provided between the glass substrate and the redistribution layer.
4. The packaging structure according to claim 1, characterized in that, A solder resist layer is provided on the lower surface of the rewiring layer.
5. The packaging structure according to claim 1, characterized in that, The thickness of the glass substrate is 300μm-800μm, including the values at both ends.
6. The packaging structure according to claim 1, characterized in that, The number of rewiring layers is 1 to 4, and includes the values at both ends.
7. The packaging structure according to claim 1, characterized in that, The conductive bumps include gold bumps; And / or, the height of the conductive bump is 10μm-25μm, including the values at both ends.
8. The packaging structure according to claim 1, characterized in that, The solder balls include tin balls.
9. The packaging structure according to claim 1, characterized in that, The thickness of the encapsulation structure is less than 900 μm.
10. The packaging structure according to any one of claims 1 to 9, characterized in that, The gap between the photoelectric sensing chip and the glass substrate is filled with sealant, and the sealant covers all the conductive bumps. The glass substrate, the photoelectric sensing chip, and the sealant enclose a sealed cavity; the photosensitive area is located within the sealed cavity.