阅读说明：本技术 一种流体检测芯片的封装结构及封装方法 (Packaging structure and packaging method of fluid detection chip ) 是由 李程远 李永智 吕军 金科 赖芳奇 于 2020-12-29 设计创作，主要内容包括：本发明涉及芯片封装技术领域,公开了一种流体检测芯片的封装结构及封装方法。流体检测芯片的封装结构包括透明盖板、晶圆片、围堰和焊球。透明盖板上垂直开设有通液孔。晶圆片包括相背设置的第一端面和第二端面,第一端面上设有感光检测区和焊垫,第二端面上设有刻蚀凹部,焊垫与刻蚀凹部正对设置。围堰首尾相连呈封闭状,且围堰的一端与透明盖板连接,另一端与晶圆片连接,以使透明盖板、晶圆片和围堰之间形成空腔,感光检测区置于空腔内,通液孔与空腔正对设置。焊球设置在第二端面上并与焊垫电连接。本发明提高了检测结果的准确性与可靠性,降低了生产难度和生产成本,提高了生产效率。(The invention relates to the technical field of chip packaging, and discloses a packaging structure and a packaging method of a fluid detection chip. The packaging structure of the fluid detection chip comprises a transparent cover plate, a wafer, a cofferdam and a welding ball. The transparent cover plate is vertically provided with a liquid through hole. The wafer comprises a first end face and a second end face which are arranged in an opposite mode, a photosensitive detection area and a welding pad are arranged on the first end face, an etching concave portion is arranged on the second end face, and the welding pad is arranged opposite to the etching concave portion. The cofferdam is in a closed shape in an end-to-end mode, one end of the cofferdam is connected with the transparent cover plate, the other end of the cofferdam is connected with the wafer, a cavity is formed among the transparent cover plate, the wafer and the cofferdam, the photosensitive detection area is arranged in the cavity, and the liquid through hole is opposite to the cavity. The solder balls are arranged on the second end surface and are electrically connected with the solder pads. The invention improves the accuracy and reliability of the detection result, reduces the production difficulty and the production cost and improves the production efficiency.)

1. A packaging structure of a fluid detection chip is characterized by comprising:

the liquid-permeable cover plate comprises a transparent cover plate (1), wherein a liquid-permeable hole (11) is vertically formed in the transparent cover plate;

the wafer (2) comprises a first end face and a second end face which are arranged in an opposite mode, wherein the first end face is provided with a photosensitive detection area (21) and a welding pad (23), the second end face is provided with an etching concave part (22), and the welding pad (23) is arranged opposite to the etching concave part (22);

the cofferdam (3) is connected end to form a closed shape, one end of the cofferdam (3) is connected with the transparent cover plate (1), the other end of the cofferdam is connected with the wafer (2), so that a cavity (31) is formed among the transparent cover plate (1), the wafer (2) and the cofferdam (3), the photosensitive detection area (21) is arranged in the cavity (31), and the liquid through hole (11) is arranged opposite to the cavity (31);

and the solder balls (6) are arranged on the second end face and are electrically connected with the welding pads (23).

2. The packaging structure of the fluid detection chip as claimed in claim 1, further comprising a metal conductive layer (5), wherein the metal conductive layer (5) is disposed on the second end surface and in the etched recess (22), and the metal conductive layer (5) is electrically connected to both the pad (23) and the solder ball (6).

3. The packaging structure of a fluid detection chip according to claim 2, further comprising a passivation layer (4), wherein the passivation layer (4) is disposed between the wafer (2) and the metal conductive layer (5).

4. The encapsulation structure of the fluid detection chip as claimed in claim 3, wherein the passivation layer (4) in the etched recess (22) has a laser hole, the laser hole is disposed opposite to the pad (23), and the metal conductive layer (5) is electrically connected to the pad (23) through the laser hole.

5. The packaging structure of the fluid detection chip as claimed in claim 2, further comprising a solder mask layer (8), wherein the solder mask layer (8) is disposed on a side of the metal conductive layer (5) opposite to the wafer (2); and an opening is formed in the solder mask layer (8), one end of the solder ball (6) is arranged in the opening and is electrically connected with the metal conducting layer (5), and the other end of the solder ball protrudes out of the opening.

6. A method for packaging a fluid detection chip, which is used for manufacturing the packaging structure of the fluid detection chip according to any one of claims 1 to 5, the method comprising:

s1, providing the transparent cover plate (1) with the liquid through hole (11);

s2, manufacturing the cofferdam (3) on the transparent cover plate (1) with the hole;

s3, providing the wafer (2), wherein the photosensitive detection area (21) and the welding pad (23) are arranged on the first end face of the wafer (2)

S4, bonding the transparent cover plate (1) with the cofferdam (3) and the first end face of the wafer (2);

s5, grinding the second end face of the wafer (2), and thinning the wafer (2) to a preset thickness;

s6, etching and forming the etching concave part (22) on the second end face after grinding;

s7, arranging the solder balls (6) on the second end face of the wafer (2);

and S8, cutting the wafer (2) to form single chips (10).

7. The method for packaging a fluid detection chip as claimed in claim 6, wherein after step S2, the method further comprises: s21, cleaning the transparent cover plate (1) with the cofferdam (3).

8. The method for packaging a fluid detection chip as claimed in claim 6, wherein in step S4, the dam (3) of the transparent cover plate (1) is bonded to the wafer (2) by a bonding adhesive layer (7).

9. The packaging method of the fluid detection chip as claimed in claim 6, wherein the packaging structure of the fluid detection chip further comprises a metal conductive layer (5) and a solder resist layer (8), the metal conductive layer (5) is disposed on the second end surface and in the etched recess (22), the solder resist layer (8) is disposed on a side of the metal conductive layer (5) opposite to the wafer (2) and electrically connected to the pad (23), and an opening is formed in the solder resist layer (8);

in step S7, the method specifically includes:

s71, arranging the metal conductive layer (5) on the wafer (2);

s72, arranging the solder mask layer (8) on the metal conducting layer (5);

s73, placing the solder balls (6) in the openings on the solder mask layer (8).

10. The packaging method of the fluid detection chip as claimed in claim 9, wherein the packaging structure of the fluid detection chip further comprises a passivation layer (4), the passivation layer (4) is disposed between the wafer (2) and the metal conductive layer (5), the passivation layer (4) in the etched recess (22) has a laser hole, the laser hole is disposed opposite to the pad (23), and the metal conductive layer (5) is electrically connected to the pad (23) through the laser hole;

in step S71, the method specifically includes:

s711, arranging the passivation layer (4) on the wafer (2);

s712, laser drilling is carried out on the passivation layer (4) in the etching concave part (22) to form the laser hole, so that the welding pad (23) is exposed from the laser hole;

s713, arranging the metal conducting layer (5) in one side of the passivation layer (4) opposite to the wafer (2) and in the laser hole.

Technical Field

The invention relates to the technical field of chip packaging, in particular to a packaging structure and a packaging method of a fluid detection chip.

Background

In recent years, the semiconductor industry has been rapidly developed, and semiconductor chips have advantages of small size, sensitivity, easy integration, and the like, and have been widely researched and applied in recent years. The microfluidic chip has the advantages of small size of functional units, high precision, rapid and convenient detection and the like, and has obvious advantages in cell analysis. The technology can integrate all the existing cell analysis steps and processes on one chip, realize the integration of analysis operation, reduce the damage and pollution to cell samples in the operation process, and is very suitable for the rapid and high-sensitivity detection of a small amount of cell characteristic parameters. The fluid detection chip provided by the invention is the microfluidic chip, a wafer of some fluid detection chips is generally concavely provided with a microchannel, the bottom of the microchannel is provided with a photosensitive detection area, liquid such as blood flows to the photosensitive detection area through the microchannel, and the photosensitive detection area is illuminated, so that the whole analysis process can be automatically completed. Among the prior art, in order to prevent fluid pollution, can cover one deck encapsulation apron above the sensitization detection zone, be connected through the glue film between wafer and the encapsulation apron, in order to guarantee the illumination among the testing process, generally set up the light trap on the glue film, the light trap is corresponding with the sensitization detection zone. The structure has the advantages of complex processing process, reduced production efficiency and increased production cost. And only set up the light trap on the glue film that corresponds the sensitization detection zone for other regions in the microchannel are invisible, can't get rid of the influence of other factors to the testing result.

Accordingly, there is a need for a fluid detection chip package structure and a method for packaging the same to solve the above-mentioned problems.

Disclosure of Invention

The invention aims to provide a packaging structure of a fluid detection chip, which improves the accuracy and reliability of a detection result, reduces the production difficulty and the production cost and improves the production efficiency.

In order to achieve the purpose, the invention adopts the following technical scheme:

a packaging structure of a fluid detection chip comprises:

the transparent cover plate is vertically provided with a liquid through hole;

the wafer comprises a first end face and a second end face which are arranged in an opposite mode, wherein the first end face is provided with a photosensitive detection area and a welding pad, the second end face is provided with an etching concave part, and the welding pad and the etching concave part are arranged in an opposite mode;

the cofferdam is connected end to form a closed shape, one end of the cofferdam is connected with the transparent cover plate, the other end of the cofferdam is connected with the wafer, so that a cavity is formed among the transparent cover plate, the wafer and the cofferdam, the photosensitive detection area is arranged in the cavity, and the liquid through hole is opposite to the cavity;

and the solder balls are arranged on the second end surface and are electrically connected with the solder pads.

Preferably, the package structure of the fluid detection chip further includes a metal conductive layer, the metal conductive layer is disposed on the second end surface and in the etching recess, and the metal conductive layer is electrically connected to the pad and the solder ball.

Preferably, the packaging structure of the fluid detection chip further includes a passivation layer disposed between the wafer and the metal conductive layer.

Preferably, the passivation layer in the etching concave part is provided with a laser hole, the laser hole is opposite to the welding pad, and the metal conducting layer is electrically connected to the welding pad through the laser hole.

Preferably, the packaging structure of the fluid detection chip further comprises a solder mask layer, and the solder mask layer is arranged on one side of the metal conductive layer, which is opposite to the wafer; and the solder mask is provided with an opening, one end of the solder ball is arranged in the opening and is electrically connected with the metal conducting layer, and the other end of the solder ball protrudes out of the opening.

Another objective of the present invention is to provide a method for packaging a fluid detection chip, which reduces the operation difficulty and the production cost of production and packaging, and improves the production efficiency.

In order to achieve the purpose, the invention adopts the following technical scheme:

a packaging method of a fluid detection chip is used for manufacturing the packaging structure of the fluid detection chip, and the method comprises the following steps:

s1, providing the transparent cover plate with the liquid through hole;

s2, manufacturing the cofferdam on the transparent cover plate with the hole;

s3, providing the wafer, wherein the photosensitive detection area and the welding pad are arranged on the first end face of the wafer

S4, bonding the transparent cover plate with the cofferdam with the first end face of the wafer;

s5, grinding the second end face of the wafer, and thinning the wafer to a preset thickness;

s6, etching the second end face after grinding to form the etched concave part;

s7, arranging the solder balls on the second end face of the wafer;

and S8, cutting the wafer to form single chips.

Preferably, after step S2, the method further includes: and S21, cleaning the transparent cover plate with the cofferdam.

Preferably, in step S4, the dam of the transparent cover plate is bonded to the wafer by a bonding glue layer.

Preferably, the packaging structure of the fluid detection chip further comprises a metal conductive layer and a solder resist layer, the metal conductive layer is arranged on the second end face and in the etching concave portion, the solder resist layer is arranged on one side, opposite to the wafer, of the metal conductive layer and is electrically connected with the solder pad, and an opening is formed in the solder resist layer;

in step S7, the method specifically includes:

s71, arranging the metal conducting layer on the wafer;

s72, arranging the solder mask layer on the metal conducting layer;

and S73, placing the solder balls in the openings on the solder mask layer.

Preferably, the packaging structure of the fluid detection chip further includes a passivation layer, the passivation layer is disposed between the wafer and the metal conductive layer, the passivation layer in the etching recess is provided with a laser hole, the laser hole is disposed opposite to the pad, and the metal conductive layer is electrically connected to the pad through the laser hole;

in step S71, the method specifically includes:

s711, arranging the passivation layer on the wafer;

s712, laser drilling is conducted on the passivation layer in the etching concave part to form the laser hole, so that the welding pad is exposed from the laser hole;

and S713, arranging the metal conducting layer on one side of the passivation layer opposite to the wafer and in the laser hole.

The invention has the beneficial effects that:

the packaging structure of fluid detection chip that this embodiment provided adopts and sets up the through-liquid hole on transparent cover, and encloses into the cavity between transparent cover, wafer and the cofferdam, and sensitization detection zone and through-liquid hole correspond the setting in the cavity, and the cavity is as the miniflow way, and in fluid can directly get into the cavity through the through-liquid hole, and light can be through transparent cover direct irradiation to sensitization detection zone on. The packaging structure that this embodiment provided, transparent cover plate make the fluid all visible in each process after getting into the chip, can get rid of the influence of other factors to the testing result to improved the accuracy and the reliability of testing result, and simple structure has saved the process of processing the miniflow channel on the wafer, has reduced the production degree of difficulty and manufacturing cost, has improved production efficiency.

According to the packaging method of the fluid detection chip provided by the embodiment, the transparent cover plate and the wafer are connected through the cofferdam, a cavity is formed among the transparent cover plate, the wafer and the liquid as a micro-channel, and liquid can enter the micro-channel through the liquid through hole and flow to the photosensitive detection area, so that the liquid detection process is realized. The micro-channel is prevented from being arranged on the wafer, the operation difficulty and the production cost of production and packaging are reduced, and the production efficiency is improved. And the wafer is packaged firstly and then cut into a plurality of single chips, so that the processing precision is prevented from being reduced due to the undersize of the chips in the etching process, and the precision of etching the concave part is improved.

Drawings

FIG. 1 is a cross-sectional view of a package structure of a fluid detection chip provided by an embodiment of the invention;

FIG. 2 is an enlarged view of a portion of FIG. 1 at A;

FIG. 3 is a schematic structural view of a first cross-sectional shape of a cofferdam provided by an embodiment of the present invention;

FIG. 4 is a schematic structural view of a second cross-sectional shape of a cofferdam provided by an embodiment of the present invention;

FIG. 5 is a schematic structural view of a third cross-sectional shape of a cofferdam provided by an embodiment of the present invention;

FIG. 6 is a schematic structural view of a fourth cross-sectional shape of a cofferdam provided by an embodiment of the present invention;

FIG. 7 is a schematic structural view of a fifth cross-sectional shape of a cofferdam provided by an embodiment of the present invention;

FIG. 8 is a flowchart illustrating the main steps of a method for packaging a fluid detection chip according to an embodiment of the present invention;

FIG. 9 is a flowchart illustrating the steps of a method for packaging a fluid detection chip according to an embodiment of the present invention;

FIG. 10 is a schematic structural diagram of a transparent cover plate with liquid through holes provided with a cofferdam according to an embodiment of the present invention;

FIG. 11 is a schematic structural diagram illustrating bonding of a dam to a wafer according to an embodiment of the present invention;

FIG. 12 is a schematic structural diagram of a thinned wafer according to an embodiment of the present invention;

FIG. 13 is a schematic structural diagram illustrating a first form of etched recesses formed in a wafer according to an embodiment of the present invention;

FIG. 14 is a schematic structural diagram of a second type of etched recess formed in a wafer according to an embodiment of the present invention;

FIG. 15 is a schematic structural diagram illustrating a third form of etching recesses formed in a wafer according to an embodiment of the present invention;

fig. 16 is a schematic structural diagram after a passivation layer and a metal conductive layer are disposed on the passivation layer according to an embodiment of the present invention;

fig. 17 is a schematic structural diagram after a solder resist layer is disposed on a metal conductive layer according to an embodiment of the present invention;

fig. 18 is a schematic structural diagram of a wafer with individual chips separated according to an embodiment of the present invention.

In the figure:

10. a single chip;

1. a transparent cover plate; 11. a liquid through hole;

2. a wafer; 21. a photosensitive detection area; 22. etching a concave part; 23. a pad;

3. cofferdam; 31. a cavity; 4. a passivation layer; 5. a metal conductive layer;

6. a solder ball; 7. bonding the adhesive layer; 8. and a solder resist layer.

Detailed Description

In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

The embodiment provides a packaging structure of a fluid detection chip. Specifically, as shown in fig. 1-2, the package structure of the fluid detection chip includes a transparent cover plate 1, a wafer 2, a dam 3, and solder balls 6. The transparent cover plate is vertically provided with a liquid through hole 11. The wafer 2 comprises a first end face and a second end face which are arranged oppositely, a photosensitive detection area 21 and a welding pad 23 are arranged on the first end face, an etching concave part 22 is arranged on the second end face, and the welding pad 23 is arranged opposite to the etching concave part 22. Cofferdam 3 end to end is the closed form, and cofferdam 3's one end is connected with transparent cover 1, and the other end is connected with wafer 2 to form cavity 31 between transparent cover 1, wafer 2 and the cofferdam 3, in cavity 31 was arranged in to sensitization detection zone 21, liquid through hole 11 just set up with cavity 31. The solder balls 6 are disposed on the second end surface and electrically connected to the pads 23. The packaging structure of fluid detection chip that this embodiment provided adopts and sets up logical liquid hole 11 on transparent cover 1, and encloses into cavity 31 between transparent cover 1, wafer 2 and the cofferdam 3, and sensitization detection zone 21 corresponds with logical liquid hole 11 and sets up in cavity 31, and cavity 31 is as the miniflow channel, and in the fluid can directly get into cavity 31 through logical liquid hole 11, and light can directly shine to sensitization detection zone 21 through transparent cover 1 on. In the packaging structure provided by the embodiment, the transparent cover plate 1 enables each process of fluid after entering the chip to be visible, and the influence of other factors on the detection result can be eliminated, so that the accuracy and the reliability of the detection result are improved, the structure is simple, the process of processing a micro channel on the wafer 2 is omitted, the production difficulty and the production cost are reduced, and the production efficiency is improved.

In this embodiment, there are two liquid passing holes 11, one liquid passing hole 11 is used as a liquid inlet hole, and the other liquid passing hole is used as a liquid outlet hole. In other embodiments, the number of the liquid through holes 11 can also be adjusted adaptively, and is not limited herein.

In this embodiment, the bonding glue layer 7 is disposed between the wafer 2 and the cofferdam 3, so that the firmness of the bonding between the wafer 2 and the cofferdam 3 is ensured, and the structural strength and the practicability of the chip are improved. Specifically, the wafer 2 and the dam 3 are bonded by a bonding machine. In other embodiments, the wafer 2 and the dam 3 may not be directly bonded by the bonding glue layer 7, and the bonding is not limited herein.

As shown in fig. 3-7, five shapes of the cross-section of the cavity 31 are provided. Preferably, the cross-section of the cavity 31 is circular (fig. 3), oval (fig. 4), rectangular (fig. 5), U-shaped (fig. 6) or Z-shaped (fig. 7). The concrete actual shape can be adjusted according to the actual conditions, and the cavity 31 formed by the cofferdam 3 is used as the flow channel of the detected liquid, so that each liquid through hole 11 is ensured to be communicated with the cavity 31.

Preferably, the transparent cover plate 1 is made of glass. Glass's insulating nature, light transmissivity and thermal diffusivity are better, and have certain structural strength, can observe the process that liquid detected, have guaranteed the reliability that detects, have avoided the chip high temperature moreover, influence the testing process, have improved the practicality of chip, and the protection that also can be fine is detected liquid, has avoided the impurity in the air to influence the testing process, has improved the accuracy nature and the reliability of testing result. In other embodiments, the material of the transparent cover plate 1 may also be an organic thin film.

In the present embodiment, the etching recess 22 may be a straight hole, a TSV hole, or an oblique slot, and the specific actual shape may be adjusted according to the actual situation.

Specifically, the package structure of the fluid detection chip further includes a metal conductive layer 5. A metal conductive layer 5 is disposed on the second end surface and within the etched recess 22, the metal conductive layer 5 being electrically connected to both the pad 23 and the solder ball 6. Set up metal conducting layer 5 and can realize being connected pad 23 and solder ball 6 electricity, guarantee that solder ball 6 can be connected with wafer 2 electricity, be convenient for adopt solder ball 6 to test the chip or monitor fluid, and regard metal conducting layer 5 as rewiring layer, be convenient for lay wire according to actual demand on wafer 2, improved the practicality. In the present embodiment, the metal conductive layer 5 is processed on the wafer 2 by electroplating, and the material of the metal conductive layer 5 may be a conductive material such as copper.

Further, the packaging structure of the fluid detection chip further includes a passivation layer 4. A passivation layer 4 is arranged between the wafer 2 and the metallic conductive layer 5. The insulativity between the wafer 2 and the metal conducting layer 5 is ensured, the wafer 2 is protected, and the durability and the practicability of the chip are improved. In this embodiment, the passivation layer 4 is made of polyamide (abbreviated as PA). In other embodiments, the passivation layer 4 may be made of other insulating materials, and is not limited herein.

In some embodiments, the metal conductive layer 5 is composed of a titanium layer, a copper layer, a nickel layer and a gold layer, which are sequentially stacked, the titanium layer being connected to the passivation layer 4. In other embodiments, the metal conductive layer 5 is composed of an aluminum layer, a nickel layer and a gold layer stacked in this order, the aluminum layer being connected to the passivation layer 4. It is understood that the material of the metal conductive layer 5 can also be adjusted according to actual requirements, and is not limited herein. The thickness of the metal conductive layer 5 is 2 to 20 μm.

Specifically, laser holes are opened on the passivation layer 4 in the etched concave portion 22. The laser hole is opposite to the welding pad 23, and the metal conducting layer 5 is electrically connected to the welding pad 23 through the laser hole. Laser holes are formed to facilitate electrical connection between the metal conductive layer 5 and the bonding pads 23, thereby achieving electrical connection between the solder balls 6 and the bonding pads 23. In this embodiment, the laser hole is formed by laser drilling, so that the pad 23 is exposed through the laser hole, and the metal conductive layer 5 directly extends onto the pad 23, thereby electrically connecting the pad 23 and the metal conductive layer 5. In other embodiments, holes may be formed through other processes to facilitate electrical connection between the metal conductive layer 5 and the bonding pads 23, which is not limited herein.

Preferably, the package structure of the fluid detection chip further includes a solder resist layer 8. The solder mask layer 8 is arranged on one side of the metal conducting layer 5 opposite to the wafer 2; and an opening is arranged on the solder mask layer 8, one end of the solder ball 6 is arranged in the opening and is electrically connected with the metal conducting layer 5, and the other end of the solder ball protrudes out of the opening. The solder mask layer 8 is arranged, so that the metal conducting layer 5 can be protected under the insulating effect, the metal conducting layer 5 is prevented from being corroded, and the durability and the practicability of the chip are improved. An opening is formed in the solder resist layer 8, so that the metal conductive layer 5 is exposed, and the solder ball 6 and the metal conductive layer 5 are electrically connected. Specifically, the solder resist layer 8 is made of an insulating material.

The embodiment also provides a packaging method of the fluid detection chip, which is used for manufacturing the packaging structure of the fluid detection chip. Specifically, as shown in fig. 8, the method includes:

s1, providing a transparent cover plate 1 with a liquid through hole 11;

s2, manufacturing a cofferdam 3 on the transparent cover plate 1 with the hole;

s3, providing a wafer 2, wherein a photosensitive detection area 21 and a welding pad 23 are arranged on a first end face of the wafer 2;

s4, bonding the transparent cover plate 1 with the cofferdam 3 with the first end face of the wafer 2;

s5, grinding the second end face of the wafer 2, and thinning the wafer 2 to a preset thickness;

s6, etching the ground second end face to form an etching concave part 22;

s7, providing solder balls 6 on the second end face of the wafer 2;

s8, the wafer 2 is diced to form individual chips 10.

In the method for encapsulating the fluid detection chip provided by the embodiment, the transparent cover plate 1 and the wafer 2 are connected through the cofferdam 3, a cavity 31 is formed among the three to serve as a micro channel, and liquid can enter the micro channel through the liquid through hole 11 and flow to the photosensitive detection area 21, so that the detection process of the liquid is realized. Avoiding the micro-channel from being arranged on the wafer 2, reducing the operation difficulty and the production cost of production and encapsulation and improving the production efficiency. And the wafer 2 is packaged and then cut to form a plurality of single chips 10, so that the processing precision is prevented from being reduced due to the undersize of the chips in the etching process, and the precision of etching the concave part 22 is improved.

Fig. 9 is a flowchart illustrating detailed steps of a method for packaging a fluid detection chip according to this embodiment, fig. 10-18 are step-by-step process diagrams illustrating the method for packaging a fluid detection chip according to this embodiment, and fig. 9-18 are referenced to describe the method for packaging a fluid detection chip in detail.

S1, providing the transparent cover plate 1 with the liquid through hole 11.

In this embodiment, a glass plate having a liquid through hole 11 formed therein is used as the transparent cover plate 1. The glass sheet may be round or square.

S2, forming a cofferdam 3 on the transparent cover plate 1 with the hole.

Specifically, as shown in fig. 10, the banks 3 are fixed on the transparent cover plate 1 by a photolithography process, a photoresist is applied on the transparent cover plate 1, and a photoresist layer is formed on the transparent cover plate 1 as the banks 3 by using a photolithography apparatus. The cross-section of the cavity 31 that the cofferdam 3 can enclose may be circular, oval, rectangular, U-shaped or Z-shaped.

Specifically, after step S2, the method further includes: s21, cleaning the transparent cover plate 1 with the cofferdam 3.

Specifically, generally, the removal of pollutants at a molecular level is realized by bombarding the surface of a cleaned product with plasma, or the cleaning of the transparent cover plate 1 is realized by soaking the glass cover plate 1 with the cofferdam 3 in a liquid medicine, so that the cleaning of the transparent cover plate 1 is beneficial to improving the environment in the cavity 31 of the fluid detection chip after packaging, avoiding the impurities such as dust and photoresist from remaining in the cavity 31, avoiding other factors from influencing the test result, and ensuring the accuracy and reliability of the test result of the detection chip in the detection of liquid. In addition, after the transparent cover plate 1 is cleaned, the complete transparent cover plate 1 is selected for subsequent packaging steps, and the qualification rate of subsequent chip products is guaranteed.

And S3, providing the wafer 2, and arranging the photosensitive detection area 21 and the welding pad 23 on the first end surface of the wafer 2.

Specifically, a plurality of photosensitive test areas 21 and a plurality of bonding pads 23 are uniformly spaced on the wafer 2.

And S4, bonding the transparent cover plate 1 with the cofferdam 3 and the first end face of the wafer 2.

As shown in fig. 11, specifically, in the bonding process of step S4, in order to ensure that liquid can enter the cavity through the liquid through hole 11 and can complete the detection process in the cavity 31, it needs to ensure that the liquid through hole 11 on the transparent cover plate 1 is arranged corresponding to the photosensitive detection area 21 of the fluid detection chip, an alignment machine is used to perform alignment before bonding, it is ensured that the liquid through hole 11 on the transparent cover plate 1 and the photosensitive detection area 21 can be accurately matched after alignment, the functionality and the practicability of the fluid detection chip are ensured, and the visibility of the detection process is also ensured.

Further, after the transparent cover plate 1 and the cofferdam 3 are aligned, a bonding machine is used for bonding the aligned wafer 2 and the transparent cover plate 1 by giving a certain pressure and temperature in a sealed vacuum environment. The bonding process with high temperature and high pressure is avoided, the influence of the bonding process on the chip and the photosensitive detection area 21 is reduced, and the functionality and the practicability of the fluid detection chip are further ensured.

In this embodiment, in step S4, the dam 3 of the transparent cover plate 1 is bonded to the wafer 2 through the bonding adhesive layer 7. In other embodiments, the bonding structure between the transparent cover plate 1 and the dam 3 may be configured without the bonding glue layer 7, or the transparent cover plate 1 and the wafer 1 may be connected by other means, which is not limited herein.

And S5, grinding the second end face of the wafer 2, and thinning the wafer 2 to a preset thickness.

Specifically, as shown in fig. 12, the height of the wafer 2 is directly reduced by grinding according to the height requirement of the actual chip, and can be adaptively adjusted according to the actual requirement.

And S6, etching and forming the etching concave part 22 on the ground second end face.

Specifically, as shown in fig. 13-15, the etched recess 22 may be specifically selected as a TSV hole (fig. 13), a straight hole (fig. 14) or a bevel groove (fig. 15), and the cross-sectional shape of the etched recess 22 may be adjusted as required. And the etching concave part 22 is processed by using a dry etching process, so that the etching concave part 22 can be obtained and the surface stress of the wafer 2 can be removed.

S7, solder balls 6 are provided on the second end face of the wafer 2.

As mentioned above, the package structure of the fluid detection chip further includes the metal conductive layer 5 and the solder mask layer 8, the metal conductive layer 5 is disposed on the second end surface and in the etching recess 22, the solder mask layer 8 is disposed on the side of the metal conductive layer 5 opposite to the wafer 2 and electrically connected to the solder pad 23, and the solder mask layer 8 is provided with an opening.

Then, step S7 specifically includes:

s71, a metal conductive layer 5 is provided on the wafer 2.

The metal conductive layer 5 facilitates rewiring of the chip, and improves practicality.

And according to the foregoing description, the package structure of the fluid detection chip further includes a passivation layer 4, the passivation layer 4 is disposed between the wafer 2 and the metal conductive layer 5, the passivation layer 4 in the etching recess 22 is provided with a laser hole, the laser hole is disposed opposite to the pad 23, and the metal conductive layer 5 is electrically connected to the pad 23 through the laser hole.

Then, in step S71, as shown in fig. 16, the method specifically includes:

and S711, arranging a passivation layer 4 on the wafer 2.

Specifically, the passivation layer 4 may be applied to the wafer 2 by painting or spraying, so as to improve the insulating property between the second end surface of the wafer 2 and the metal conductive layer 5. In the process of spraying the passivation layer 4, a small number of spraying methods can be used, which facilitates the inspection of the spraying quality of each layer. In other embodiments, an insulating dielectric layer may be sputtered on the surface of the wafer 2 as the passivation layer 4 by PECVD (Plasma Enhanced Chemical Vapor Deposition); or after sputtering a layer of insulating medium by using a PECVD method, spraying a layer of PA on the insulating medium to be used as a passivation layer 4.

And S712, laser drilling is carried out on the passivation layer 4 in the etched concave part 22 to form a laser hole, so that the welding pad 23 is exposed from the laser hole.

Laser holes are formed in the passivation layer 4, so that conductive connection between the metal conducting layer 5 and the welding pads 23 is facilitated, and the use and quality inspection of a chip can be guaranteed through the solder balls 6 arranged on the metal conducting layer 5.

And S713, arranging a metal conducting layer 5 in the laser hole and on the side, opposite to the wafer 2, of the passivation layer 4.

Specifically, the metal conductive layer 5 is provided by electroplating, PVD (physical vapor deposition), or chemical plating, which facilitates the laying of rewiring on the wafer 2 of the chip. Further, firstly, a titanium layer and a copper layer or an aluminum layer are sputtered on the passivation layer 4, then photoresist is coated on the preset position of the copper layer or the aluminum layer, a photoetching instrument is used for carrying out exposure development and wet etching to obtain a required rewiring pattern, and the nickel layer and the gold layer are replaced on the copper layer or the aluminum layer through replacement reaction on the required rewiring pattern.

S72, solder resist layer 8 is provided on metal conductive layer 5.

As shown in fig. 17, the solder resist layer 8 is made of an insulating material, and is laid on the metal conductive layer 5 by spin coating or spray coating to protect the metal conductive layer 5, and a plurality of openings are formed in the solder resist layer 8 to facilitate the arrangement of solder balls 6. In the process of spraying the solder resist layer 8, a small number of spraying methods can be used, so that the spraying quality of each layer can be checked conveniently. And coating photoresist on the preset position of the solder mask layer 8, and exposing and developing to obtain the solder mask layer 8 with an opening.

S73, solder balls 6 are placed in the openings on the solder resist layer 8.

Specifically, the solder balls 6 are disposed in the openings on the solder resist layer 8 by a solder ball printing process or a ball mounting process to form the package structure of the chip in fig. 1. The solder ball 6 is made of tin or tin alloy, and the tin is in contact with the gold layer of the metal conductive layer 5, so that the electric connection can be realized.

S8, the wafer 2 is diced to form individual chips 10.

As shown in fig. 18, the wafer 2 is divided into a plurality of chip packages according to the plurality of photosensitive detection regions 21, and the whole packaged fluid detection wafer is cut into single fluid detection chips by mechanical cutting or laser cutting, so as to form the chip package structure shown in fig. 1. Qualified chips are convenient to select after cutting, and unqualified chips are prevented from flowing into the subsequent production and processing process.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.