Image sensor packaging structure

Abstract

The utility model discloses an image sensor packaging structure, which relates to the technical field of semiconductor packaging and comprises a substrate, an image sensor chip, a reverse lead, a supporting layer and a light-transmitting element. According to the image sensor packaging structure, the first bending part is arranged, so that the reverse bonding wire can fully extend in the vertical direction under the condition that the overall thickness is not influenced; through the arrangement of the second bending part, the plane included angle between the reverse bonding wire and the image sensor chip is reduced; the connection can be firmer by fixedly arranging the tail solder ball on the upper side of the second bonding pad and then performing solder ball bonding on the second end of the reverse bonding wire and the upper part of the tail solder ball. The image sensor packaging structure provided by the utility model can adapt to a harsh wiring strategy or space limitation, is convenient to process, and ensures small size and high stability of the whole.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor packaging, in particular to an image sensor packaging structure. Background Art

[0002] As a key component of digital imaging devices, image sensors are responsible for converting optical images into electrical signals for further processing. Image sensors, such as CMOS and CCD, need to be designed to be very thin to ensure that light can effectively penetrate the sensor surface material to reach the photosensitive unit, reducing light absorption and scattering, thereby maintaining high-quality imaging effects. At the same time, thinner sensors also facilitate the realization of smaller pixel sizes, allowing more pixels to be integrated in a limited space and improving resolution. In short, image sensors have increasingly higher requirements for thin designs. Therefore, the wires connecting the image sensor chip and the substrate in the image sensor need to meet specific wiring strategies or space limitations, which makes processing difficult and easily destroys the stability of the image sensor. Utility Model Content

[0003] In response to the above-mentioned problems, the present invention provides an image sensor packaging structure, which enables the wires in the image sensor packaging structure to adapt to smaller-sized image sensors, facilitates processing, and ensures overall stability.

[0004] In order to achieve the above purpose, the technical solution provided by the utility model is:

[0005] Image sensor packaging structure, including:

[0006] A substrate, the substrate comprising a first surface and a second surface, the second surface being opposite to the first surface, and the substrate being provided with a plurality of first solder pads;

[0007] an image sensor chip, the image sensor chip being fixedly mounted on the first surface of the substrate, the image sensor chip including a photosensitive area, the side of the image sensor chip on which the photosensitive area is disposed being the upper surface of the image sensor chip, the side opposite to the upper surface being the lower surface of the image sensor chip, and the image sensor chip being provided with a plurality of second bonding pads;

[0008] A back-punch wire comprises a first bend, a second bend, a first end, and a second end. The first end of the back-punch wire forms a head solder ball at the first pad. The back-punch wire extends upward from the first end, extends downward through the first bend to the second bend, and extends to form a second end after reducing the plane angle between the back-punch wire and the image sensor chip through the second bend, which is concave toward the substrate. The second end of the back-punch wire is bonded to the solder ball on the second pad. The back-punch wire as a whole extends toward the plane of the image sensor chip. The distance between the substrate and the first bend is the largest relative to the distance between the substrate and other parts of the back-punch wire. The method of first connecting to the first pad of the substrate and then connecting to the second pad of the image sensor chip is called a back-punch wire. This method can minimize the space occupied between the image sensor chip and the light-transmitting element.

[0009] A support layer, the support layer being arranged along the periphery of the photosensitive area and having a penetrating light-transmitting inner cavity in the vertical direction, and the support layer being arranged on the upper surface of the image sensor chip;

[0010] The light-transmitting element is arranged above the image sensor chip and supported by the supporting layer. The image sensor chip receives a sensing signal through the light-transmitting element and the light-transmitting inner cavity.

[0011] The image sensor packaging structure provided by the present invention preferably has a tail solder ball planted at the second solder pad, and the second end of the back-punch wire is bonded to the upper solder ball of the tail solder ball. The tail solder ball is first fixed on the upper side of the second solder pad, and then the second end of the back-punch wire is solder-bonded to the upper part of the tail solder ball. This can make the connection more secure, and at the same time, the size of the tail solder ball can be controlled in advance to meet height requirements, and it is also more convenient to process.

[0012] In the image sensor packaging structure provided by the present invention, preferably, an angle between the substrate and a straight line passing through the highest point of the first bending portion and the connection point between the first end and the first pad is an acute angle.

[0013] The image sensor packaging structure provided by the present invention preferably has a reverse-punch conductor further comprising a third bending portion disposed between the first end and the first bending portion. The reverse-punch conductor extends horizontally toward the side close to the second pad and vertically after passing through the third bending portion.

[0014] In the image sensor packaging structure provided by the present invention, preferably, the support layer covers a portion of the tail solder ball and the back-punched wire.

[0015] The image sensor packaging structure provided by the present invention preferably comprises a supporting layer including an inner concave portion and an outer protruding portion, wherein the inner concave portion is adjacent to the outer protruding portion, the inner concave portion is concave inwardly toward the outer surface of the supporting layer, and the outer protruding portion is away from the light-transmitting inner cavity relative to the inner concave portion and protrudes outwardly from the light-transmitting inner cavity.

[0016] The image sensor packaging structure provided by the present invention preferably further includes a sealing body, which covers the outer side surface of the light-transmitting element, the outer side surface of the support layer, the upper surface of the image sensor chip outside the support layer, the outer side surface of the image sensor chip, and the first surface of the substrate outside the image sensor chip, and wraps the back-punched wires and head solder balls.

[0017] The above technical solution has the following advantages or beneficial effects:

[0018] The image sensor packaging structure provided by the present invention can fully extend the back-punch wire in the vertical direction without affecting the overall thickness by setting the first bend portion, thereby being away from the substrate and reducing the difficulty of processing; by setting the second bend portion, the plane angle between the back-punch wire and the image sensor chip is reduced. When the overall thickness is extremely thin, the gap between the image sensor chip and the light-transmitting element is extremely small. The reduction of the angle can make the connection between the back-punch wire and the second solder pad more convenient; when the back-punch wire starts to extend from the head solder ball, the extension angle of the back-punch wire relative to the substrate is too small, which will increase the difficulty of processing. By setting the third bend portion, it can further meet specific wiring strategies or space restrictions when the above-mentioned extension angle is large; by using a method of first fixing the tail solder ball on the upper side of the second solder pad and then solder-bonding the second end of the back-punch wire to the upper part of the tail solder ball, the connection can be made more firm and more convenient to process. In summary, the image sensor packaging structure provided by the present invention is suitable for image sensors of smaller sizes, and is convenient to process and ensures overall stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a cross-sectional view of the image sensor packaging structure of Example 1 of the present utility model.

[0020] Figure 2 This utility model Figure 1 Magnified view of part I.

[0021] Figure 3 It is a cross-sectional view of the image sensor packaging structure provided with a third bending portion according to Example 1 of the present invention.

[0022] Figure 4 This utility model Figure 3 An enlarged view of part II. DETAILED DESCRIPTION

[0023] Example 1:

[0024] Reference Figure 1 and Figure 2 The image sensor packaging structure provided in Example 1 of the present utility model includes:

[0025] A substrate 1, comprising a first surface 11 and a second surface 12, wherein the second surface 12 is opposite to the first surface 11, and the substrate 1 is provided with a plurality of first solder pads 311;

[0026] An image sensor chip 2 is fixed to the first surface 11 of the substrate 1. The image sensor chip 2 includes a photosensitive area 21. The side of the image sensor chip 2 where the photosensitive area 21 is provided is the upper surface of the image sensor chip 2, and the side opposite to the upper surface is the lower surface of the image sensor chip 2. The image sensor chip 2 is provided with a plurality of second bonding pads 321.

[0027] The back-punch wire 30 has a first bend portion 303, a second bend portion 304, a first end 301, and a second end 302. The first end 301 of the back-punch wire 30 forms a head solder ball 31 at the first pad 311. The back-punch wire 30 extends upward from its first end 301, extends downward through the first bend portion 303 to the second bend portion 304, and extends to form a second bend portion 304 by the second bend portion 304 concave toward the substrate 1. The second end 302 of the back-punch wire 30 is solder-bonded to the second pad 321. The back-punch wire 30 extends toward the plane of the image sensor chip 2. The distance between the substrate 1 and the first bent portion 303 is the largest compared to the distance between the substrate 1 and the rest of the back-punch wire 30. The method of first connecting to the first pad 311 of the substrate 1 and then connecting to the second pad 321 of the image sensor chip 2 is called a back-punch wire. This method can minimize the space occupied between the image sensor chip 2 and the light-transmitting element 5.

[0028] A support layer 4 is provided along the periphery of the photosensitive area 21 and has a penetrating light-transmitting inner cavity 6 in the vertical direction. The support layer 4 is provided on the upper surface of the image sensor chip 2;

[0029] The light-transmitting element 5 is disposed above the image sensor chip 2 and supported by the supporting layer 4 . The image sensor chip 2 receives sensing signals through the light-transmitting element 5 and the light-transmitting inner cavity 6 .

[0030] Specifically, a tail solder ball 32 is planted at the second pad 321, and the second end 302 of the reverse wire 30 is bonded to the upper portion of the tail solder ball 32. The tail solder ball 32 is first fixed on the upper side of the second pad 321, and then the second end 301 of the reverse wire 30 is bonded to the upper portion of the tail solder ball 32. This makes the connection more secure, and the size of the tail solder ball 32 can be controlled in advance to meet height requirements, which is also more convenient for processing.

[0031] Specifically, an angle a1 between the substrate 1 and a straight line passing through the highest point of the first bent portion 303 and the connection point between the first end 301 and the first pad 311 is an acute angle.

[0032] Specifically, the reverse wire 30 further has a third bending portion 305 disposed between the first end 301 and the first bending portion 303 . The reverse wire 30 extends horizontally toward the second pad 321 and vertically after passing through the third bending portion 305 .

[0033] Specifically, the support layer 4 covers the tail solder ball 32 and a portion of the back-punch wire 30 .

[0034] Specifically, the supporting layer 4 includes an outward protrusion 4a and an inward concave portion 4b, wherein the inward concave portion 4b is adjacent to the outward protrusion 4a, and the inward concave portion 4b is concave inward toward the outer surface of the supporting layer 4, and the outward protrusion 4a is away from the light-transmitting inner cavity 6 relative to the inward concave portion 4b and protrudes outward from the light-transmitting inner cavity 6.

[0035] Specifically, it also includes a sealing body 7, which covers the outer side surface of the light-transmitting element 5, the outer side surface of the support layer 4, the upper surface of the image sensor chip 2 outside the support layer 4, the outer side surface of the image sensor chip 2, and the first surface 11 of the substrate outside the image sensor chip 2, and wraps the back-punched wire 30 and the head solder ball 31.

[0036] The image sensor package structure provided by the present invention utilizes a reverse-punch method for processing. A first bend 303 is provided to control the height of the reverse-punch conductor 30, allowing the reverse-punch conductor 30 to fully extend vertically without affecting the overall thickness. This allows the reverse-punch conductor 30 to be positioned away from the substrate 1, reducing processing difficulty and improving overall stability. A second bend 304 is also provided to reduce the planar angle between the reverse-punch conductor 30 and the image sensor chip 2, accommodating the distance between the image sensor chip 2 and the light-transmitting element 5. The reduced angle also allows the reverse-punch conductor 30 to adjust its relative position to the second pad 321, thereby reducing processing difficulty and meeting the requirements of demanding wiring strategies or space constraints. When extending from the head solder ball 31, the initial extension angle of the back-punch wire 30 relative to the substrate 1 is too small, which may affect the surrounding components and require high processing precision, thereby increasing the processing difficulty. By further providing the third bend 305, the initial extension angle can be set larger. Adjusting the curvature of the third bend 305 can easily adapt to the height and width restrictions of the back-punch wire 30, thereby further meeting the demanding wiring strategy or space restrictions with low processing difficulty. In summary, the image sensor packaging structure of the present invention can adapt to more demanding wiring strategies or space restrictions, while being easy to process and ensuring the overall small size and high stability.

[0037] The following will be combined with the drawings of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described in this application are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

Claims

1. An image sensor packaging structure, characterized in that: include: A substrate (1), the substrate (1) comprising a first surface (11) and a second surface (12), the second surface (12) being opposite to the first surface (11), and the substrate (1) being provided with a plurality of first solder pads (311); An image sensor chip (2), the image sensor chip (2) being fixedly mounted on the first surface (11) of the substrate (1), the image sensor chip (2) comprising a photosensitive region (21), the side of the image sensor chip (2) on which the photosensitive region (21) is arranged being the upper surface of the image sensor chip (2), the side opposite to the upper surface being the lower surface of the image sensor chip (2), and the image sensor chip (2) being provided with a plurality of second bonding pads (321); The back-punch wire (30) comprises a first bending portion (303), a second bending portion (304), a first end (301) and a second end (302); the first end (301) of the back-punch wire (30) forms a head solder ball (31) at a first solder pad (311); the back-punch wire (30) extends upward from the first end (301), extends downward through the first bending portion (303) to the second bending portion (304), and passes through a second bending portion (304) that is concave toward the substrate (1). The second bending portion (304) is extended to form a second end (302) after reducing the plane angle between the back-punching wire (30) and the image sensor chip (2). The second end (302) of the back-punching wire (30) is bonded to the solder ball of the second pad (321). The back-punching wire (30) as a whole extends in a plane direction close to the image sensor chip (2). Compared with the spacing between the substrate (1) and other parts of the back-punching wire (30), the spacing between the substrate (1) and the first bending portion (303) is the largest. A support layer (4), the support layer (4) being arranged along the periphery of the photosensitive area (21) and having a penetrating light-transmitting inner cavity (6) in the vertical direction, and the support layer (4) being arranged on the upper surface of the image sensor chip (2); A light-transmitting element (5) is provided above the image sensor chip (2) and supported by the supporting layer (4); the image sensor chip (2) receives a sensing signal through the light-transmitting element (5) and the light-transmitting inner cavity (6).

2. The image sensor package structure according to claim 1, wherein: A tail solder ball (32) is planted at the second solder pad (321), and the second end (302) of the back-punched wire (30) is bonded to the upper solder ball of the tail solder ball (32).

3. The image sensor package structure according to claim 1, wherein: The angle (a1) between the straight line passing through the highest point of the first bending portion (303) and the connection point between the first end (301) and the first solder pad (311) and the substrate (1) is an acute angle.

4. The image sensor package structure according to any one of claims 1 to 3, wherein: The reverse-beating conductor (30) further comprises a third bending portion (305) provided between the first end (301) and the first bending portion (303); the reverse-beating conductor (30) extends horizontally toward a direction close to the second solder pad (321) after passing through the third bending portion (305), and extends vertically.

5. The image sensor package structure according to claim 1, wherein: The support layer (4) covers the tail solder ball (32) and a portion of the back-punch wire (30).

6. The image sensor packaging structure according to claim 1 or 5, wherein: The support layer (4) comprises an outer protruding portion (4a) and an inner concave portion (4b), wherein the inner concave portion (4b) is adjacent to the outer protruding portion (4a), the inner concave portion (4b) is concave inwardly toward the outer surface of the support layer (4), and the outer protruding portion (4a) is away from the light-transmitting inner cavity (6) relative to the inner concave portion (4b) and protrudes outward from the light-transmitting inner cavity (6).

7. The image sensor package structure according to claim 1, wherein: The invention also includes a sealing body (7), wherein the sealing body (7) covers the outer side surface of the light-transmitting element (5), the outer side surface of the support layer (4), the upper surface of the image sensor chip (2) outside the support layer (4), the outer side surface of the image sensor chip (2), and the first surface (11) of the substrate outside the image sensor chip (2), and wraps the back-punched wire (30) and the head solder ball (31).

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