CN204538006U - The encapsulating structure of New Image process chip - Google Patents

Abstract

The utility model discloses a packaging structure of a novel image processing chip, which comprises an image sensing chip, a printed circuit support plate, a transparent cover plate and a PCB substrate; a raised portion is located in the middle of the inner side of the printed circuit support plate, and the periphery of the transparent cover plate The area is in contact with the raised part, and there are several blind holes distributed around the edge area of the upper surface of the image sensor chip. The bottom of the blind hole of the image sensor chip has an aluminum pad, which is located in the blind hole and has nickel on the upper surface of the aluminum pad in turn. Layer, protective metal layer; the metal conductive layer is electrically connected to the circuit on the lower surface of the raised portion of the printed circuit support plate through conductive glue, the image sensor chip is located between the raised portion and the PCB substrate, and the PCB substrate and the bottom of the printed circuit support plate The electrical connection is bonded by conductive glue, and the metal conductive layer is composed of a copper conductive layer and a tin conductive layer from bottom to top. The utility model has better thermal shock resistance and water vapor shock resistance performance, improves the optical performance of the module and reduces the production cost.

Description

Package structure of new image processing chip

technical field

The utility model relates to an image sensor package structure, which belongs to the technical field of semiconductor package.

Background technique

Image sensors have been widely used in digital devices such as digital cameras, camera phones, and the like. The image sensor module includes an image sensor for converting image information into electrical information. Specifically, an image sensor may include a semiconductor device capable of converting photons into electrons to display and store images. Examples of image sensors include Point and Coupled Devices (CCD), Complementary Metal Oxide Silicon (CMOS) Image Sensors (CIS), etc.

One packaging method of the existing image sensor is to make a dam cavity on the glass substrate and apply bonding glue, bond the wafer and the glass substrate together, and use through-silicon vias and rewiring technology to complete the wafer-level of the chip. Packaged and finally diced into single dies. But there are the following technical problems:

The main problems solved by this technology are as follows:

(1) The welding pad structure produced by the fab is made of aluminum, so the front side photolithography and development process of the wafer will corrode the aluminum metal welding pad. This technology electroless nickel-plates aluminum pads after wafer incoming to protect the aluminum pads from being corroded by alkaline developer.

(2) Use easy-to-remove special materials to protect the pixel area of the wafer, so as to ensure that the subsequent front-side process of the wafer will not affect the pixel area;

(3) Make a layer of pressure stress buffer layer under the wafer bumps to solve the problem of low reliability of the bumps.

(4) Wafer bumps are directly grown on the aluminum solder joints on the front of the wafer, which greatly reduces the line transmission distance and solves the problem of unstable signal transmission;

(5) Using wafer bump technology to achieve ultra-fine pitch packaging;

(6) Use the hollow printed circuit board in the middle, weld the chip and the printed circuit board with the flip-chip technology, and embed the chip into the printed circuit board to make the thickness of the packaging module thinner;

(7) The IR glass sheet is attached to the hollow part of the PCB to enhance the optical performance of the product.

(8) This technology solves the problem of product warping encountered in CSP processing of high-pixel, large-size image sensor products.

(9) This technology greatly simplifies the product packaging process, eliminating the need for dry etching in the TSV process, resulting in higher production efficiency and lower costs.

Contents of the invention

The purpose of the utility model is to provide a packaging structure of a novel image processing chip. The packaging structure of the novel image processing chip adopts front connection, the silicon layer under the metal pad is complete, and the supporting force is better than the previous technology. The point will not break, the product has better thermal shock and water vapor shock resistance, and the wafer bump is directly grown on the aluminum solder joint on the front of the wafer, which greatly reduces the line transmission distance and makes the signal transmission more stable.

In order to achieve the above purpose, the technical solution adopted by the utility model is: a new type of packaging structure for image processing chips, including image sensor chips, printed circuit support boards, transparent cover plates and PCB substrates, the center of the printed circuit support boards There is a hollow area, the transparent cover covers the hollow area, and the upper surface of the image sensor chip has a photosensitive area;

There is a raised portion located in the middle of the inner side of the printed circuit support plate, and the peripheral area of the transparent cover is in contact with the raised portion, thereby forming a cavity between the transparent cover and the image sensing chip;

A number of blind holes are distributed around the edge area of the upper surface of the image sensing chip, and the bottom of the blind hole of the image sensing chip has an aluminum pad, which is located in the blind hole and has a nickel layer and a protective metal layer on the upper surface of the aluminum pad. , located on the upper surface of the image sensing chip and has a pressure buffer layer around the blind hole, the bottom, side surface and upper surface of the pressure buffer layer of the blind hole have a titanium copper layer, and the blind hole is filled with a metal conductive layer , the height of the metal conductive layer is higher than the depth of the blind hole and extends to the surface of the titanium copper layer directly above the pressure buffer layer, so that the upper part of the metal conductive layer covers a part of the titanium copper layer directly above the pressure buffer layer, and the pressure The buffer layer is the developed photoresist layer;

The metal conductive layer is electrically connected to the circuit on the lower surface of the raised portion of the printed circuit support plate through conductive glue, the image sensing chip is located between the raised portion and the PCB substrate, and the PCB substrate and the bottom of the printed circuit support plate are electrically connected The adhesive is used for electrical connection, and the metal conductive layer is composed of a copper conductive layer and a tin conductive layer from bottom to top.

The scheme of further improvement in above-mentioned technical scheme is as follows:

1. In the above solution, the raised portion is located in the middle of the inner side of the printed circuit support board.

2. In the above scheme, the protective metal layer is a nickel-gold layer or a nickel-palladium layer.

Due to the application of the above-mentioned technical solutions, the utility model has the following advantages and effects compared with the prior art:

1. The packaging structure of the new image processing chip of the utility model replaces the back connection method in the TSV (Through Silicon Via) process, adopts the front connection method, the silicon layer under the metal pad is complete, and the supporting force is higher than that of the previous technology Even better, the metal solder joints will not break, and the product has better thermal shock and water vapor impact performance. Wafer bumps are directly grown on the aluminum solder joints on the front of the wafer, which greatly reduces the line transmission distance and makes signal transmission easier. Stable; secondly, its metal conductive layer is composed of copper conductive layer and tin conductive layer from bottom to top, which is beneficial to further reduce contact resistance and response time; thirdly, printed circuit board and chip with hollow center Flip-chip welding greatly reduces the thickness of the chip module, greatly improves the optical performance of the module and reduces production costs.

2. The packaging structure of the image processing chip of the utility model has an aluminum pad at the bottom of the blind hole of the image sensing chip, which is located in the blind hole and has a nickel layer and a protective metal layer on the aluminum pad surface in turn for the aluminum of the wafer. For metal pads, the pads should be protected first to effectively prevent the influence of subsequent processes on them and improve product reliability.

3. The packaging structure of the image processing chip of the utility model, which is located on the upper surface of the image sensing chip and has a pressure buffer layer around the blind hole, the pressure buffer layer is a photoresist layer after development, metal bumps A stress buffer layer is made at the bottom to effectively improve the welding reliability of metal bumps.

Description of drawings

Accompanying drawing 1 is the structural representation of the image sensing chip in the package structure of the utility model image processing chip;

Accompanying drawing 2 is the enlarged schematic view of the local structure at A in the accompanying drawing 1;

Accompanying drawing 3 is the enlarged schematic view of the structure of the printed circuit support plate of the present invention;

Accompanying drawing 4 is a schematic diagram of the packaging structure of the new image processing chip of the present invention.

In the above drawings: 1. Image sensor chip; 2. Printed circuit support plate; 3. Transparent cover plate; 4. PCB substrate; 5. Hollow area; 6. Photosensitive area; ;9, blind hole; 10, aluminum pad; 11, nickel layer; 12, protective metal layer; 13, pressure buffer layer; 14, titanium copper layer; 15, metal conductive layer; 151, copper conductive layer; 152, Tin conductive layering; 16. Conductive glue; 17. V-shaped groove.

Detailed ways

Below in conjunction with embodiment the utility model is further described:

Embodiment: A packaging structure of a new type of image processing chip, including an image sensor chip 1, a printed circuit support plate 2, a transparent cover plate 3 and a PCB substrate 4, the center of the printed circuit support plate 2 has a hollow area 5, and the The transparent cover plate 3 covers the hollow area 5, and the upper surface of the image sensing chip 1 has a photosensitive area 6;

There is a raised part 7 located in the middle of the inner side of the printed circuit support board 2, and the peripheral area of the transparent cover 3 is in contact with the raised part 7, thereby forming a cavity between the transparent cover 3 and the image sensor chip 1 8;

There are several blind holes 9 distributed around the edge area of the upper surface of the image sensor chip 1, and the bottom of the blind holes 9 of the image sensor chip 1 has an aluminum pad 10, which is located in the blind hole 9 and on the upper surface of the aluminum pad 10. It has a nickel layer 11 and a protective metal layer 12 in sequence, and is located on the upper surface of the image sensor chip 1 and has a pressure buffer layer 13 around the blind hole 9. The bottom, side surface and upper surface of the pressure buffer layer of the blind hole 9 have a Titanium copper layer 14, the blind hole 9 is filled with a metal conductive layer 15, the metal conductive layer 15 is higher than the depth of the blind hole 9 and extends to the surface of the titanium copper layer 14 directly above the pressure buffer layer 13, so that The upper part of the metal conductive layer 15 covers a part of the titanium-copper layer 14 directly above the pressure buffer layer 13, which is a developed photoresist layer;

The metal conductive layer 15 is electrically connected to the lower surface circuit of the raised portion 7 of the printed circuit support plate 2 through the conductive glue 16, and the image sensor chip 1 is located between the raised portion and the PCB substrate 4, and the PCB substrate 4 It is electrically connected to the bottom of the printed circuit support board 2 through conductive glue 16 , and the metal conductive layer 15 is composed of a copper conductive layer 151 and a tin conductive layer 152 from bottom to top.

The raised portion 7 is located in the middle of the inner surface of the printed circuit support board 2 .

The above-mentioned protective metal layer 12 is a nickel-gold layer or a nickel-palladium layer.

When the package structure of the above-mentioned new image processing chip is adopted, it replaces the back connection method in the TSV (Through Silicon Via) process, and adopts the front connection method, the silicon layer under the metal pad is complete, and the supporting force is better than the previous process , the metal solder joints will not break, the product has better thermal shock and water vapor impact performance, and the wafer bumps are directly grown on the aluminum solder joints on the front of the wafer, which greatly reduces the line transmission distance and more stable signal transmission; Secondly, its metal conductive layer is composed of copper conductive layer and tin conductive layer from bottom to top, which is beneficial to further reduce contact resistance and response time; thirdly, the printed circuit board with hollow center and chip flip chip Welding greatly reduces the thickness of the chip module, greatly improves the optical performance of the module and reduces production costs; again, the bottom of the blind hole of the image sensor chip has an aluminum pad, which is located in the blind hole and on the aluminum pad The surface has a nickel layer and a protective metal layer in turn. For the aluminum metal pad of the wafer, the pad is first protected to effectively prevent the subsequent process from affecting it and improve product reliability; again, it is located on the upper surface of the image sensor chip and There is a pressure buffer layer around the blind hole, and the pressure buffer layer is a photoresist layer after development, and a stress buffer layer is made on the bottom of the metal bump to effectively improve the welding reliability of the metal bump.

The above-mentioned embodiments are only to illustrate the technical concept and characteristics of the present utility model, and its purpose is to enable those familiar with this technology to understand the content of the present utility model and implement it accordingly, and not to limit the protection scope of the present utility model. All equivalent changes or modifications made according to the spirit of the utility model shall fall within the protection scope of the utility model.

Claims (3)

1. A packaging structure for a novel image processing chip, characterized in that it includes an image sensor chip (1), a printed circuit support plate (2), a transparent cover plate (3) and a PCB substrate (4), and the printed circuit There is a hollow area (5) at the center of the support plate (2), the transparent cover plate (3) covers the hollow area (5), and the upper surface of the image sensing chip (1) has a photosensitive area (6); There is a raised part (7) located in the middle of the inner side of the printed circuit support board (2), and the peripheral area of the transparent cover (3) is in contact with the raised part (7), so that the transparent cover (3) and A cavity (8) is formed between the image sensing chips (1); There are several blind holes (9) distributed around the edge area around the upper surface of the image sensing chip (1), and the bottom of the blind holes (9) of the image sensing chip (1) has an aluminum pad (10), which is located in the blind hole A nickel layer (11) and a protective metal layer (12) are sequentially provided in (9) and on the upper surface of the aluminum pad (10), located on the upper surface of the image sensor chip (1) and around the blind hole (9). The pressure buffer layer (13), the bottom of the blind hole (9), the side surface and the upper surface of the pressure buffer layer have a titanium copper layer (14), and the blind hole (9) is filled with a metal conductive layer (15), The metal conductive layer (15) is higher than the depth of the blind hole (9) and extends to the surface of the titanium copper layer (14) directly above the pressure buffer layer (13), so that the upper part of the metal conductive layer (15) covers the A partial area of the titanium-copper layer (14) directly above the buffer layer (13), the pressure buffer layer (13) being a developed photoresist layer; The metal conductive layer (15) is electrically connected to the circuit on the lower surface of the raised portion (7) of the printed circuit support plate (2) through conductive glue (16), and the image sensor chip (1) is located between the raised portion and the PCB Between the substrates (4), the PCB substrate (4) is electrically connected to the bottom of the printed circuit support plate (2) through conductive glue (16), and the metal conductive layer (15) is composed of copper conductive layers from bottom to top. Layer (151) and tin conductive layer (152) are superimposed. 2. The package structure of the novel image processing chip according to claim 1, characterized in that: the raised portion (7) is located in the middle of the inner surface of the printed circuit support board (2). 3. The package structure of the novel image processing chip according to claim 1, characterized in that: the protective metal layer (12) is a nickel-gold layer or a nickel-palladium layer.