Sawtooth bonding type light sensation packaging structure capable of directly receiving and emitting light
By using the design of the second chip and the third chip in the light sensing packaging structure, combining the through hole and the serrated side, the problems of large size, poor heat dissipation and light transmission in the prior art are solved, and the problem of large packaging structures is realized. Efficient heat dissipation and light transmission effect reduce cost and volume.
Patent Information
- Application Number
- CN202411350139.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2024-12-31
AI Technical Summary
The existing light sensing package has large structure size, poor heat dissipation function, and affected light transmission effect.
The second chip is used instead of the traditional substrate, and the third chip is used to replace the packaging glue. By opening a through-hole structure and a sawtooth connection on the third chip, combining PVD sputtered metal layer and metal pad to achieve electrical connection, reducing the thickness and cost of the packaging structure. , improve light transmittance and heat dissipation efficiency.
The volume reduction of the packaging structure, the light transmittance reaches 100%, and the heat dissipation efficiency is increased by more than 50%, avoiding the problems of cover warping and high wire arcing, and ensuring the high reliability and low cost of the packaging structure.
Smart Images
Figure CN119230538A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of optical sensing packaging technology, and more particularly to a serrated connection optical sensing packaging structure that directly emits and receives light. Background Technology
[0002] Existing optical sensor packaging structures include a substrate, a photosensitive chip, a light-emitting chip, a transparent packaging structure, and a light-shielding barrier. For example, Chinese patent CN117673062A discloses a light-shielding packaging structure and packaging method for an optical sensor. The photosensitive chip and the light-emitting chip are mounted on the substrate. A transparent molding layer is disposed on the upper surface of the substrate and covers the photosensitive chip and the light-emitting chip. The upper side of the transparent molding layer is also provided with a first protrusion corresponding to the upper and lower parts of the photosensitive chip and a second protrusion corresponding to the upper and lower parts of the light-emitting chip. The light-shielding barrier is located between the photosensitive chip and the light-emitting chip.
[0003] The existing optical sensor packaging structure has the following technical problems: 1. The photosensitive chip and the light-emitting chip are packaged in a transparent structure, which results in poor heat dissipation and affects the overall packaging quality and operational reliability of the optical sensor. Although the transparent packaging structure has light-transmitting properties, it still reduces the light transmission effect to some extent (the light transmittance is usually <90%).
[0004] 2. The transparent packaging structure has an outer shell, and the substrate and chip itself have a certain thickness, resulting in a large overall size of the packaging structure. The shell is also prone to warping and other deformations after being heated. At the same time, the photosensitive chip and the light-emitting chip are electrically connected to the substrate by wire bonding. The wire bonding has a certain arc height, about 75±25um, which further increases the size of the packaging structure.
[0005] Therefore, there is a need for a serrated bonding photosensitive packaging structure that can directly receive and emit light, which can solve the problems of large size, poor heat dissipation, and affected light transmission in existing photosensitive packaging structures. Summary of the Invention
[0006] The purpose of this invention is to provide a serrated bonding photosensitive packaging structure that directly receives and emits light, which can solve the problems of large size, poor heat dissipation, and affected light transmission in existing photosensitive packaging structures.
[0007] This invention is implemented as follows: A direct light-emitting serrated bonding photosensitive packaging structure includes a first chip, a second chip, a third chip, a serrated bonding surface, and an electrical connection structure. The third chip is disposed on the top surface of the second chip, and a first opening and a second opening are formed on the third chip at intervals. The first opening penetrates the third chip along its thickness direction, so that the light-emitting end of the second chip is located within the first opening. The first chip is disposed on the top surface of the second chip and embedded in the third chip, and the light-emitting end of the first chip is located within the second opening. The serrated bonding surface is disposed on the bottom surface of the second chip, so that the second chip is electrically connected to the product through the serrated bonding surface. The second chip, the first chip, and the third chip are connected by the electrical connection structure.
[0008] The sum of the thickness of the second chip and the depth of the second opening is the same as the thickness of the third chip, so that the second opening penetrates the third chip upwards.
[0009] Both the first and second openings are truncated cone structures that are wider at the top and narrower at the bottom.
[0010] The bottom surface of the second chip has a plurality of serrated portions spaced apart. The serrated bonding surface is made of conductive material and fills the gaps between adjacent serrated portions, forming a conductive connection surface on the bottom surface of the second chip.
[0011] The electrical connection structure includes a first electrical connection structure connecting the second chip and the third chip, and a second electrical connection structure connecting the first chip and the second chip.
[0012] The first electrical connection structure includes a first sputtered metal layer and a first metal pad; the first sputtered metal layer is formed by metal sputtering on the side of the second chip away from the first chip, and the first sputtered metal layer extends from the bottom of the second chip to the bonding surface between the second chip and the third chip and is electrically connected to the third chip through the first metal pad.
[0013] The second electrical connection structure includes a second sputtered metal layer and a second metal pad; the second sputtered metal layer is formed by metal sputtering on the side of the second chip close to the first chip, and the second sputtered metal layer extends from the bottom of the second chip through the bonding surface of the second chip and the third chip to the bonding surface of the first chip and the third chip, and is electrically connected to the first chip through the second metal pad.
[0014] Compared with the prior art, the present invention has the following advantages: 1. By using a second chip instead of a traditional substrate and a third chip instead of traditional encapsulating adhesive, the thickness of the encapsulation structure can be reduced. The first and second sputtered metal layers are formed by PVD sputtering instead of traditional wire bonding, which can be attached to the surface of the chip. While ensuring the conductivity effect, the size of the encapsulation structure is further reduced, and the encapsulation cost can be reduced.
[0015] 2. By opening the first and second openings on the third chip, the present invention ensures the direct emission and reception of the light beam through the through-hole structure, achieving a light transmittance of 100%. It also helps to improve the heat dissipation efficiency of the first and second chips. It eliminates the need for a transparent packaging structure, cover, and glass, further reducing packaging costs. It also avoids the problems of burrs and heat warping of the cover, ensuring the high reliability of the packaging structure.
[0016] 3. Because the present invention has a serrated bonding surface, the serrated structure formed by the serrated part at the bottom of the second chip can significantly increase the heat dissipation area at the bottom of the second chip, which can improve the heat dissipation efficiency by more than 50%. At the same time, the serrated bonding surface ensures the uniform distribution of conductive material, so that the bottom of the second chip can dissipate heat evenly and reliably conduct with the product, without the need for heat dissipation through the substrate, and can achieve the function of a traditional substrate. Attached Figure Description
[0018] Figure 1 This is a cross-sectional view of the serrated bonding type photosensitive packaging structure for direct light emission of the present invention.
[0019] In the figure, 1 is the first chip, 2 is the second chip, 201 is the serrated part, 3 is the third chip, 301 is the first opening, 302 is the second opening, 4 is the serrated bonding surface, 501 is the first electrical connection structure, 5011 is the first sputtered metal layer, 5012 is the first metal pad, 502 is the second electrical connection structure, 5021 is the second sputtered metal layer, and 5022 is the second metal pad. Detailed Implementation
[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0021] Please see the appendix Figure 1A direct light-emitting serrated bonding photosensitive packaging structure includes a first chip 1, a second chip 2, a third chip 3, a serrated bonding surface 4, and an electrical connection structure. The third chip 3 is disposed on the top surface of the second chip 2, and a first opening 301 and a second opening 302 are formed on the third chip 3 at intervals. The first opening 301 penetrates the third chip 3 along the thickness direction, so that the light-emitting end of the second chip 2 is located in the first opening 301. The first chip 1 is disposed on the top surface of the second chip 2 and embedded in the third chip 3, and the light-emitting end of the first chip 1 is located in the second opening 302. The serrated bonding surface 4 is disposed on the bottom surface of the second chip 2, so that the second chip 2 is electrically connected to the product through the serrated bonding surface 4. The second chip 2, the first chip 1, and the third chip 3 are connected by the electrical connection structure.
[0022] In this invention, a third chip 3 replaces the encapsulating adhesive, transparent glass, and cover. Holes 301 and 302 are formed on the third chip 3 by laser engraving or cutting through a mold groove, thus improving the problems of burrs and heat-induced warping deformation in traditional encapsulation structures. The first chip 1 and the second chip 2 can be photosensitive chips and light-emitting chips, respectively, fulfilling direct light emission and light absorption functions through the first and second openings 301 and 302. The third chip 3 can be a chip required for the encapsulation structure or the product itself, to achieve product functions such as optical sensing.
[0023] Since the first opening 301 and the second opening 302 are not filled with transparent encapsulation structures and glass covers, 100% light transmittance can be effectively guaranteed, ensuring that the light transmittance is not affected by the transparent encapsulation structure. This also saves on the amount of transparent encapsulation structure and glass used, reducing encapsulation costs. At the same time, since the first opening 301 and the second opening 302 are separated by the material of the third chip 3, they are opaque to each other, which avoids mutual interference between the light emission and light absorption functions.
[0024] In this invention, a second chip 2 is used instead of a substrate. The serrated bonding surface 4 satisfies the electrical connection and heat dissipation requirements between the second chip 2 and the product, realizing the function of a traditional substrate. Thus, by eliminating the substrate, the thickness of the packaging structure can be reduced by at least 200um.
[0025] In this invention, an electrical connection structure is used instead of wire bonding to achieve electrical connection between the second chip 2, the first chip 1, and the third chip 3. While ensuring the reliability of the electrical connection, the problem of increased package thickness caused by wire bonding arc height is avoided, and the thickness of the package structure can be further reduced.
[0026] Meanwhile, the first opening 301 and the second opening 302 ensure efficient heat dissipation of the first chip 1 and the second chip 2, and the serrated bonding surface 4 further improves the heat dissipation efficiency of the second chip 2.
[0027] The sum of the thickness of the second chip 2 and the depth of the second opening 302 is the same as the thickness of the third chip 3, so that the second opening 302 penetrates the third chip 3 upwards, thus ensuring the light-receiving or light-emitting function of the second chip 2.
[0028] The first opening 301 and the second opening 302 are both truncated cone structures that are wider at the top and narrower at the bottom, which is beneficial for the emission and reception of light and further ensures the light transmittance.
[0029] Preferably, the dimensions of the first aperture 301 and the second aperture 302 can be adaptively adjusted according to the dimensions of the light-emitting and light-receiving ends and the emission and reflection range of light.
[0030] The bottom surface of the second chip 2 is provided with a plurality of serrated portions 201 spaced apart. The serrated bonding surface 4 is made of conductive material and fills the gap between adjacent serrated portions 201, forming a conductive connection surface on the bottom surface of the second chip 2.
[0031] Preferably, the conductive material can be a conductive silver paste, solder paste or other materials with good conductivity, so as to ensure the electrical connection of the second chip 2 on the product.
[0032] The serrated structure formed by several serrated portions 201 can increase the contact area between the conductive material and the second chip 2, which can significantly improve the heat dissipation efficiency (heat dissipation efficiency improvement > 50%), while also ensuring the reliability of the electrical connection between the second chip 2 and the product.
[0033] The electrical connection structure includes a first electrical connection structure 501 connecting the second chip 2 and the third chip 3 and a second electrical connection structure 502 connecting the first chip 1 and the second chip 2, ensuring the electrical connection requirements within the package structure.
[0034] The positions of the first electrical connection structure 501 and the second electrical connection structure 502 can be adaptively arranged according to the connection requirements of the chip.
[0035] The first electrical connection structure 501 includes a first sputtered metal layer 5011 and a first metal pad 5012; the first sputtered metal layer 5011 is formed by metal sputtering on the side of the second chip 2 away from the first chip 1, and the first sputtered metal layer 5011 extends from the bottom of the second chip 2 to the bonding surface between the second chip 2 and the third chip 3 and is electrically connected to the third chip 3 through the first metal pad 5012.
[0036] Preferably, the first sputtered metal layer 5011 can be formed by PVD (Physical Vapor Deposition) metal sputtering. The first sputtered metal layer 5011 can be attached to the surface of the chip, has a small thickness, and can ensure the conductivity reliability of electrical connection through the conductivity of metal. Compared with the traditional wire bonding method, it is more conducive to reducing the size of the package structure and the cost is also lower.
[0037] The second electrical connection structure 502 includes a second sputtered metal layer 5021 and a second metal pad 5022; the second sputtered metal layer 5021 is formed by metal sputtering on the side surface of the second chip 2 near the first chip 1, and the second sputtered metal layer 5021 extends from the bottom of the second chip 2 through the bonding surface of the second chip 2 and the third chip 3 to the bonding surface of the first chip 1 and the third chip 3, and is electrically connected to the first chip 1 through the second metal pad 5022.
[0038] Preferably, a second sputtered metal layer 5021 can be formed by PVD metal sputtering. The second sputtered metal layer 5021 can be attached to the surface of the chip, has a small thickness, and can ensure the conductivity reliability of the electrical connection through the conductivity of the metal. Compared with the traditional wire bonding method, it is more conducive to reducing the size of the package structure and the cost is also lower.
[0039] Please see the appendix Figure 1 The packaging method of the present invention is as follows: Using a second chip 2 (light-emitting chip) as a substrate, a serrated portion 201 is formed on the bottom surface of the second chip 2. A serrated bonding surface 4 of uniform thickness is formed in the gap of the serrated portion 201 and on the bottom surface of the second chip 2 by conductive silver paste or solder paste.
[0040] The first chip 1 (light-receiving chip) is mounted onto the second chip 2. A first sputtered metal layer 5011 and a second sputtered metal layer 5021 are formed on both sides of the second chip 2 by PVD metal sputtering. The first sputtered metal layer 5011 extends to the top surface of the second chip 2, and the second sputtered metal layer 5021 extends to the top surface of the first chip 1.
[0041] A hole is made in the third chip 3 to form a first hole 301 and a second hole 302. The third chip 3 is then attached to the top surface of the second chip 2, so that the light-emitting end of the second chip 2 is located at the bottom of the first hole 301 and the light-receiving end of the first chip 1 is located at the bottom of the second hole 302. The third chip 3 and the second chip 2 are electrically connected through the first metal pad 5012, and the first chip 1 and the second chip 2 are electrically connected through the second metal pad 5022.
[0042] The second chip 2 is connected to the product requiring optical sensing functionality via the serrated interface 4. The light-emitting end of the second chip 2 emits light directly through the first opening 301 with 100% transmittance. The light is then reflected directly to the second opening 302 with 100% transmittance and received by the light-receiving end of the first chip 1, thus realizing the optical sensing function. Other functions of the package structure are implemented by the first chip 1, the second chip 2, and the third chip 3 according to the product's functional requirements, and will not be elaborated here.
[0043] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A sawtooth-bonded light-sensing packaging structure for directly receiving and emitting light, characterized by: The invention comprises a first chip (1), a second chip (2), a third chip (3), a sawtooth bonding surface (4) and an electrical connection structure; the third chip (3) is arranged on the top surface of the second chip (2); a first opening (301) and a second opening (302) are formed on the third chip (3) at intervals; the first opening (301) penetrates the third chip (3) along the thickness direction of the third chip (3), so that the light-emitting and light-emitting end of the second chip (2) is located in the first opening (301); the first chip (1) is arranged on the top surface of the second chip (2) and embedded in the third chip (3), and the light-emitting and light-emitting end of the first chip (1) is located in the second opening (302); the sawtooth bonding surface (4) is arranged on the bottom surface of the second chip (2), so that the second chip (2) is electrically connected to the product through the sawtooth bonding surface (4), and the second chip (2), the first chip (1) and the third chip (3) are electrically connected through the electrical connection structure.
2. The sawtooth-bonded light-sensing packaging structure for directly receiving and emitting light according to claim 1 is characterized in that: The sum of the thickness of the second chip (2) and the depth of the second opening (302) is consistent with the thickness of the third chip (3), so that the second opening (302) penetrates the third chip (3) upwards.
3. The sawtooth-bonded light-sensing packaging structure for directly receiving and emitting light according to claim 1 is characterized in that: The first opening (301) and the second opening (302) are both truncated cone structures that are wide at the top and narrow at the bottom.
4. The sawtooth-bonded light-sensing packaging structure for directly receiving and emitting light according to claim 1 is characterized in that: A plurality of sawtooth portions (201) are formed at intervals on the bottom surface of the second chip (2); the sawtooth connecting surface (4) is made of a conductive material; the sawtooth connecting surface (4) fills the gaps between adjacent sawtooth portions (201) and forms a conductive connection surface on the bottom surface of the second chip (2).
5. The sawtooth bonding type light sensing packaging structure for directly receiving and emitting light according to claim 1 is characterized in that: The electrical connection structure comprises a first electrical connection structure (501) connecting the second chip (2) and the third chip (3), and a second electrical connection structure (502) connecting the first chip (1) and the second chip (2).
6. The sawtooth-bonded light-sensing packaging structure for directly receiving and emitting light according to claim 5 is characterized in that: The first electrical connection structure (501) comprises a first sputtered metal layer (5011) and a first metal pad (5012); the first sputtered metal layer (5011) is formed by metal sputtering on a side surface of the second chip (2) away from the first chip (1), and the first sputtered metal layer (5011) extends from the bottom of the second chip (2) to between the bonding surfaces of the second chip (2) and the third chip (3) and is electrically connected to the third chip (3) through the first metal pad (5012).
7. The sawtooth-bonded light-sensing packaging structure for directly receiving and emitting light according to claim 5 is characterized in that: The second electrical connection structure (502) comprises a second sputtered metal layer (5021) and a second metal pad (5022); the second sputtered metal layer (5021) is formed by metal sputtering on a side surface of the second chip (2) close to the first chip (1), and the second sputtered metal layer (5021) extends from the bottom of the second chip (2) through the bonding surface of the second chip (2) and the third chip (3) to between the bonding surfaces of the first chip (1) and the third chip (3) and is electrically connected to the first chip (1) through the second metal pad (5022).