Packaging structure and packaging method of large-size image sensor

Abstract

The invention discloses a packaging structure of a large-size image sensor, belongs to the technical field of chip packaging, and the full-glass packaging structure can ensure good flatness and thermal matching. Good electric connection and signal transmission are realized through metalized layers arranged on the front and back surfaces of the glass substrate and through conductive through holes. Meanwhile, the arrangement of the glass cover plate and the glass supporting side wall provides protection for the image sensor chip, and the stability and reliability of the structure are enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of chip packaging, and in particular relates to a packaging structure and a packaging method for a large-size image sensor. Background Art

[0002] Image sensor chips usually use processes such as wire bonding, flip-chip bonding or direct wafer bonding to achieve signal interconnection. For large-size chips exceeding 50mm×50mm, direct wafer bonding has high packaging costs and insufficient reliability. Flip-chip bonding has the risk of solder joint failure and is not suitable for large-size chip interconnection. The traditional wire bonding method has high reliability and low implementation cost, and is a better process route. When large-size chips are bonded to the substrate, there are high requirements for the flatness of the substrate. Even if the ceramic shell is mechanically polished, the flatness can only reach about 50µm, which cannot meet the bonding requirements of large-size chips. The commonly used resin-based packaging substrate has insufficient thermal matching with silicon, and when the size is large, it is easy to have bonding failure caused by internal stress. Summary of the invention

[0003] The present invention provides a packaging structure and packaging method for a large-size image sensor, which solves the problem of insufficient thermal matching between a commonly used resin-based packaging substrate and silicon, and easy adhesion failure caused by thermal mismatch when the size is large.

[0004] To achieve the above object, the present invention provides the following technical solutions: A packaging structure for a large-size image sensor comprises a glass substrate, wherein metallization layers are arranged on both the front and back sides of the glass substrate, the metallization layers on the front and back sides are connected via conductive through holes penetrating the glass substrate, an image sensor chip and a glass cover plate are arranged on the front side of the glass substrate in sequence from bottom to top, a glass supporting side wall is arranged between the glass cover plate and the glass substrate, the glass supporting side wall is arranged around the glass substrate and the glass cover plate, and the sensor chip is connected to the metallization layer on the front side via bonding wires.

[0005] Preferably, the conductive via is formed by laser induced etching technology, and the conductive via is filled with metal.

[0006] Preferably, the area of ​​the back metallization layer is larger than the area of ​​the front metallization layer.

[0007] Preferably, the glass supporting sidewalls and the image sensor chip are fixed to the front surface of the glass substrate by adhesive.

[0008] Preferably, the size of the image sensor chip is not less than 50 mm×50 mm.

[0009] Preferably, the thickness of the glass supporting sidewall is greater than the thickness of the image sensor chip by more than 0.2 mm.

[0010] Preferably, the glass cover plate is made of sapphire glass.

[0011] Preferably, the optical glass cover plate is fixed to the glass supporting side wall by adhesive.

[0012] A packaging method for a large-size image sensor, comprising: A glass substrate with metallized layers on the front and back sides is used, and conductive through holes are provided to electrically connect the metallized layers on the front and back sides; The glass support side walls are fixed around the glass substrate using organic adhesive; The image sensor chip is fixed in the middle of the front side of the glass substrate using an organic adhesive; Connecting the sensor chip pad and the metallization layer on the front side of the glass substrate by wire bonding; Bond the optical glass cover plate to the glass support side wall.

[0013] Preferably, an inverted bonding method is used to achieve bonding and fixing of the glass supporting side wall on the glass substrate.

[0014] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a packaging structure of a large-size image sensor, which realizes good electrical connection and signal transmission through the metallization layer and the conductive through-holes arranged on the front and back sides of the glass substrate. At the same time, the arrangement of the glass cover plate and the glass supporting side wall provides protection for the image sensor chip, and enhances the stability and reliability of the structure.

[0015] Furthermore, the conductive vias are formed by laser induced etching technology and filled with metal, which can precisely control the shape and size of the vias, improve the conductivity and connection stability, and reduce the loss in signal transmission.

[0016] Furthermore, the area of ​​the back metallization layer is larger than that of the front metallization layer, which facilitates the welding of cables, and is particularly important for large-sized image sensor chips.

[0017] Furthermore, the thickness of the glass support side wall is greater than the thickness of the image sensor chip by more than 0.2 mm, leaving sufficient space for wire bonding to prevent stress from being transferred to the wire when subjected to external force.

[0018] Furthermore, sapphire glass is used as the glass cover. Sapphire glass has high hardness, high light transmittance and good wear resistance, and can effectively protect the image sensor chip while ensuring good optical performance.

[0019] Furthermore, the optical glass cover plate is fixed to the glass support side wall by adhesive, and the adhesive can provide a sealing effect to prevent external impurities from entering the interior of the packaging structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the packaging structure of a large-size image sensor of the present invention; Figure 2 This is a partial enlarged view of the packaging structure of a large-size image sensor of the present invention; Figure 3 It is a schematic diagram of inverted bonding of glass substrates; In the figure, 1, glass support side wall 2, conductive through hole 3, glass substrate 4, image sensor chip 5, metallization layer 6, adhesive 7, bonding wire 8, optical glass cover 9, positioning tooling DETAILED DESCRIPTION In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0023] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0024] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0025] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0027] like Figure 1 and 2 As shown, the present invention provides a packaging structure of a large-size image sensor, which mainly includes a glass substrate 3, a glass support side wall 1, an image sensor chip 4, and an optical glass cover plate 8. Among them: the glass support side wall 1 is bonded and fixed to the edge of the glass substrate 3 to form a glass shell, the image sensor chip 4 is bonded and fixed in the middle of the glass substrate 3, and the optical glass cover plate 8 is bonded and fixed above the glass support side wall 1 to protect the inside of the device.

[0028] The front and back surfaces of the glass substrate 3 are both provided with metallization layers 5, and are connected through conductive through holes 2. The conductive through holes 2 need to be formed by laser induced etching technology, and metal is filled in the through holes to form a conductive path. The front metallization layer 5 is used as a bonding finger to form an electrical connection with the image sensor chip 4, and the back metallization layer 5 is used for welding cables or other forms of lead-out terminals. The area of ​​the back metallization layer should be larger than that of the front metallization layer.

[0029] The size of the image sensor chip 4 is not less than 50mm×50mm, the thickness of the glass support side wall 3 is more than 0.2mm larger than the chip thickness, leaving sufficient space between the bonding wire 7 and the optical glass cover plate 8, and the width of the glass support side wall 1 should be at least 4mm to ensure sufficient bonding area between it and the glass substrate 3 and the optical glass cover plate 8.

[0030] The glass support sidewall 1 and the image sensor chip 4 are fixed to the surface of the glass substrate 3 by means of adhesive 6. The adhesive 6 should be a low-stress adhesive or adhesive film, and usually an ultraviolet curing or room temperature curing adhesive material is selected.

[0031] The electrical signal of the image sensor chip 4 is led out to the metallization layer 5 on the front side of the glass substrate through the bonding wire 7 , and then led out to the outside of the device through the conductive through hole 2 of the glass substrate 3 .

[0032] The optical glass cover plate 8 is fixed to the glass supporting side wall 1 by means of adhesive 6, so as to protect the interior of the device and optimize the light.

[0033] The optical glass cover plate 8 may be sapphire glass, and an anti-reflection film may be coated on its surface to enhance its light transmittance according to product characteristics.

[0034] like Figure 3 As shown, this patent provides a method for bonding a long glass support side wall 1. The glass support side wall 1 is placed in a positioning tool 9. After glue is applied on the top of the side wall, the glass substrate 3 is bonded inverted on the top of the glass support side wall 1. By applying uniform pressure on the top of the substrate, the consistency of the thickness of the glue layer of the four glass support side walls 1 and the flatness of the surface of the formed sealing frame can be ensured, which can avoid the tilting problem or inconsistent orientation problem that often occurs during the bonding process of long objects. At the same time, through this inverted bonding method, the time for bonding the glass support side walls 1 one by one is reduced, which is convenient for improving production efficiency.

[0035] Finally, the large-size image sensor packaging structure can be fixed to the system components by dispensing glue on the edges. When high reliability is required, the bottom of the device can be directly bonded to a high-flatness structural substrate with a screw fixing structure.

[0036] Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments and application fields, and the above-mentioned specific embodiments are only illustrative and instructive, rather than restrictive. Under the guidance of the specification, a person skilled in the art can also make many forms without departing from the scope of protection of the claims of the present invention, all of which belong to the scope of protection of the present invention.

Claims

1. A packaging structure of a large-size image sensor, characterized in that: The invention comprises a glass substrate (3), wherein a metallization layer (5) is arranged on both the front and back surfaces of the glass substrate (3), the metallization layers on the front and back surfaces are connected via conductive through holes (2) penetrating the glass substrate (3), an image sensor chip (4) and a glass cover plate (8) are arranged on the front surface of the glass substrate (3) in order from bottom to top, a glass support side wall (1) is arranged between the glass cover plate (8) and the glass substrate (3), the glass support side wall (1) is arranged around the glass substrate (3) and the glass cover plate (8), and the sensor chip (4) is connected to the metallization layer (5) on the front surface via bonding wires (7).

2. The packaging structure of a large-size image sensor according to claim 1, characterized in that: The conductive through hole (2) is formed by laser induced etching technology, and the conductive through hole (2) is filled with metal.

3. The packaging structure of a large-size image sensor according to claim 1, characterized in that: The area of ​​the back metallization layer (5) is greater than the area of ​​the front metallization layer (5).

4. The packaging structure of a large-size image sensor according to claim 1, characterized in that: The glass supporting side wall (1) and the image sensor chip (4) are fixed to the front surface of the glass substrate (3) by means of adhesive (6).

5. The packaging structure of a large-size image sensor according to claim 1, characterized in that: The size of the image sensor chip (4) is not less than 50 mm×50 mm.

6. The packaging structure of a large-size image sensor according to claim 1, characterized in that: The thickness of the glass supporting side wall (3) is greater than the thickness of the image sensor chip (4) by more than 0.2 mm.

7. The packaging structure of a large-size image sensor according to claim 1, characterized in that: The glass cover plate (8) is made of sapphire glass.

8. The packaging structure of a large-size image sensor according to claim 1, characterized in that: The optical glass cover plate (8) is fixed to the glass supporting side wall (1) by means of adhesive (6).

9. A packaging method for a large-size image sensor, characterized in that: include: A glass substrate (3) having a metallized layer (5) on the front and back sides is used, and a conductive through hole (2) is provided to electrically connect the metallized layers (5) on the front and back sides; Using organic adhesive to fix the glass support side wall (1) around the glass substrate (3); Using organic adhesive to fix the image sensor chip (4) in the middle of the front side of the glass substrate (3); Connecting the sensor chip (4) pad and the metallization layer on the front side of the glass substrate (3) by wire bonding; An optical glass cover plate (8) is bonded onto the glass supporting side wall (1).

10. The packaging method of a large-size image sensor according to claim 9, characterized in that: The glass supporting side wall (1) is bonded and fixed on the glass substrate (3) by adopting an inverted bonding method.

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