CN108091660B

CN108091660B - Image sensor

Info

Publication number: CN108091660B
Application number: CN201611159737.3A
Authority: CN
Inventors: 杨省枢; 张香鈜
Original assignee: Industrial Technology Research Institute ITRI
Current assignee: Industrial Technology Research Institute ITRI
Priority date: 2016-11-23
Filing date: 2016-12-15
Publication date: 2020-07-31
Anticipated expiration: 2036-12-15
Also published as: TW201820852A; TWI613915B; CN108091660A; CN108110020B; CN108110020A

Abstract

The invention discloses an image sensor, which comprises a substrate, an image sensing element and a glue layer. The substrate has a cambered surface. The image sensing element is arranged on the cambered surface, wherein the image sensing element bends along with the cambered surface. The adhesive layer is arranged on the cambered surface and covers the image sensing element.

Description

Image sensor

Technical Field

The present invention relates to an image sensor, and more particularly, to an image sensor including a curved image sensing element.

Background

In recent years, due to the rapid development of multimedia technology, digital images are used more frequently, and the demands of consumers for image processing devices are increasing. Many digital image products, such as web cameras (webcams), digital cameras (digital cameras), smart phones (smart phones), etc., capture images through an image sensor (image sensor).

For a complementary metal oxide semiconductor image sensing element (CMOS image sensing element), the CMOS image sensing element can be designed to be curved to change the optical properties thereof, so as to reduce the number of corresponding lenses required to achieve miniaturization of the image sensing module. Generally, an unbent image sensor is first placed on an arc surface of a substrate, the arc surface of the substrate has a through hole aligned with the image sensor, and then the image sensor is driven to bend downwards through the through hole in an air-extracting manner and attached to the arc surface of the substrate, so as to obtain a bent image sensor. However, this method requires the formation of the through hole for air extraction on the substrate, which makes the manufacturing process time-consuming, and the substrate has an incomplete structure due to the formation of the through hole, which cannot firmly support the image sensor, which may cause the image sensor to deform undesirably at the through hole. In addition, in a general image sensor module, the image sensor element is not covered by the colloid, so that foreign matters (such as dust in the environment) are easily attached to the image sensor element in the manufacturing process, thereby reducing the quality of the image sensor module.

Disclosure of Invention

The present invention is directed to an image sensor, which can save the manufacturing cost, stably support the image sensor, and prevent the foreign material from adhering to the image sensor during the manufacturing process.

The image sensor of the invention comprises a substrate, an image sensing element and an adhesive layer. The substrate has a cambered surface. The image sensing element is arranged on the cambered surface, wherein the image sensing element bends along with the cambered surface. The adhesive layer is arranged on the cambered surface and covers the image sensing element.

In view of the above, in the image sensor of the present invention, the arc surface of the substrate is provided with an adhesive layer for covering the image sensing element in addition to the image sensing element. Therefore, in the process of pressing the image sensing element and the adhesive layer onto the cambered surface of the substrate, the image sensing element can be bent along with the cambered surface by pushing the image sensing element through the adhesive layer. Because the image sensing element is not bent by air extraction as mentioned above, the invention does not need to form a through hole for air extraction at the cambered surface of the substrate as the traditional manufacturing process, thereby simplifying the manufacturing process and saving the manufacturing cost. In addition, the substrate of the present invention does not need to form a through hole as mentioned above, so the structure of the substrate is complete and the image sensing device can be stably supported. Furthermore, the image sensing element is coated by the adhesive layer, so that foreign matters can be prevented from being attached to the image sensing element in the manufacturing process.

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

FIG. 1A is a cross-sectional view of an image sensor according to an embodiment of the present invention;

FIG. 1B is a top view of a portion of the image sensor of FIG. 1A;

FIG. 2 is a cross-sectional view of an image sensor according to another embodiment of the present invention;

FIG. 3A is a cross-sectional view of an image sensor according to another embodiment of the present invention;

FIGS. 3B to 3E are flow charts of a method for fabricating an image sensor according to an embodiment of the present invention;

FIG. 3F is a graph showing the variation of ambient pressure, pressing force and temperature in the manufacturing process of the image sensor of FIG. 3A;

FIG. 4 is a cross-sectional view of an image sensor according to another embodiment of the present invention;

fig. 5 is a schematic view of a cover, an adhesive layer and an image sensor device according to another embodiment of the invention.

Description of the symbols

100. 200, 300, 400: image sensor

110. 210, 310, 410: substrate

110a, 210a, 310a, 410 a: cambered surface

110b, 210b, 310b, 410 b: glue discharging groove

120. 220, 320, 420, 520: image sensing element

130. 230, 330 ', 430, 530': glue layer

140. 340, 440, 540: cover body

150. 250, 350: conductive structure

152. 252, 352: conductive circuit

154. 254, 354, 454: conductive vias

154a, 254a, 354a, 156, 256, 356, 456: connecting pad

160. 260, 360, 460, 560: conductive element

A1, a2, A3: line segment

D: direction of rotation

E1, E2, E3, E4: end tip

H: distance between two adjacent plates

h: height difference

R1, R2, R3, R4: flange

S1: upper side

S2: lower side

T: thickness of

t 1-t 7: time of day

Detailed Description

Fig. 1A is a cross-sectional view of an image sensor according to an embodiment of the invention. Referring to fig. 1A, the image sensor 100 of the present embodiment includes a substrate 110, an image sensing element 120, a glue layer 130, and a cover 140. The substrate 110 has a curved surface 110a, and the image sensor 120 is disposed on the curved surface 110a of the substrate 110, such that the image sensor 120 is curved along with the curved surface 110a of the substrate 110. The adhesive layer 130 is disposed on the arc surface 110a of the substrate 110 to cover the image sensor 120. The cover 140 is disposed on the substrate 110 to cover the image sensor 120 and the adhesive layer 130. In the present embodiment, the image sensing element 120 is, for example, a Complementary Metal Oxide Semiconductor (CMOS) image sensing element, but the invention is not limited thereto.

Specifically, the substrate 110 of the embodiment has an upper side S1 and a lower side S2 opposite to each other, the arc surface 110a is located on the upper side S1 of the substrate 110, and the arc surface 110a is a concave arc surface as shown in fig. 1A to form a groove on the substrate 110, the image sensor 120 is disposed in the groove, the adhesive layer 130 is filled in the groove, and the curvature of the image sensor 120 is the same as the curvature of the arc surface 110 a. In other embodiments, the arc surface 110a may also be a convex arc surface and the image sensor 120 is disposed on the convex arc surface, which is not limited in the present invention.

As described above, the arc surface 110a of the substrate 110 is provided with the image sensor 120 and the adhesive layer 130 for covering the image sensor 120. Therefore, in the process of pressing the image sensor 120 and the adhesive layer 130 onto the curved surface 110a of the substrate 110, the image sensor 120 can be bent along with the curved surface 110a by pushing the image sensor 120 by the adhesive layer 130. Since the image sensor 120 is not bent by pumping as described above, it is not necessary to form a through hole for pumping at the arc surface 110a of the substrate 110 as in the conventional manufacturing process, and the manufacturing process can be simplified to save the manufacturing cost. In addition, since the substrate 110 of the present embodiment has no through hole at the arc surface 110a, the structure of the substrate 110 is complete and the image sensor 120 can be stably supported. Furthermore, the image sensor 120 is covered by the adhesive layer 130, so that foreign materials can be prevented from adhering to the image sensor 120 during the manufacturing process.

Referring to fig. 1A, a maximum distance H between the top surface of the image sensor 120 and the cover 140 of the present embodiment is, for example, smaller than a thickness T of the cover 140. For example, the distance H is 12.5 to 100 microns, and the thickness T is 200 to 1000 microns. The height difference h of the top surface of the image sensor 120 in the vertical direction of fig. 1A is, for example, greater than 12.5 μm, but the invention is not limited thereto.

FIG. 1B is a top view of a portion of the image sensor of FIG. 1A. For clarity, the adhesive layer 130, the cover 140 and the conductive element 160 in fig. 1A are not shown in fig. 1B. Referring to fig. 1A and 1B, the substrate 110 of the present embodiment has at least one row of glue grooves 110B (shown as a plurality of grooves), and the glue grooves 110B extend from the periphery of the image sensor 120 to the edge of the arc surface 110a, so that the excess glue generated during the formation of the glue layer 130 can be discharged through the glue grooves 110B. Specifically, the arc surface 110a of the present embodiment has a plurality of flanges R1 surrounding the image sensor 120, and the flanges R1 are arranged at intervals to form the glue dispensing grooves 110 b. In addition, the ends E1 of the flanges R1 surround the image sensor 120 to form positioning recesses, so that the image sensor 120 is positioned in the positioning recesses formed by the ends E1 of the flanges R1.

In the present embodiment, the contour of the outer edge of the arc surface 110a is rectangular as shown in fig. 1B, and the positioning concave portion formed by the end E1 of the flanges R1 is rectangular as shown in fig. 1B, but the invention is not limited thereto. In other embodiments, the outer edge of the arc surface 110a may have a circular shape or other suitable shape, and the positioning recess formed by the end E1 of the flange R1 may have a circular shape or other suitable shape. In addition, in the embodiment, the arc surface 110a has a curvature only in the direction D, but the invention is not limited thereto, and in other embodiments, the arc surface 110a may also have curvatures in other directions to form a bowl-shaped groove.

As shown in fig. 1A and 1B, the image sensor 100 includes a conductive structure 150, wherein the conductive structure 150 is disposed on the substrate 110 and electrically connected to the image sensor 120, and extends from below the image sensor 120 to outside the arc surface 110a, so that the image sensor 120 can transmit signals through the conductive structure 150. Specifically, the image sensor 100 includes at least one conductive element 160 (two are shown), and the conductive structure 150 includes at least one conductive line 152 (two are shown), at least one conductive via 154 (two are shown, such as a Through Silicon Via (TSV)), and at least one pad 156 (two are shown). The conductive elements 160 are, for example, conductive bumps and disposed between the image sensor 120 and the curved surface 110a, and the two conductive elements 160 are electrically connected to the image sensor 120 and are electrically connected to the two pads 156 of the conductive structure 150, respectively. The two pads 156 are disposed on the arc surface 110a and respectively connected to the two conductive traces 152, the two conductive traces 152 extend from the inside of the arc surface 110a to the outside of the arc surface 110a along the upper side S1 of the substrate 110 and are respectively connected to the two conductive vias 154, and each conductive via 154 is connected to the corresponding conductive trace 152 by the pad 154a located on the upper side S1 of the substrate 110 and penetrates from the outside of the arc surface 110a to the lower side S2 of the substrate 110. In the present embodiment, each conductive trace 152 of the conductive structure 150 extends to the outside of the arc surface 110a along the glue discharging groove 110b, for example, but the invention is not limited thereto.

Fig. 2 is a cross-sectional view of an image sensor according to another embodiment of the invention. In the embodiment shown in fig. 2, the substrate 210, the arc surface 210a, the glue discharging groove 210b, the image sensing device 220, the glue layer 230, the conductive structure 250, the conductive trace 252, the conductive via 254, the pad 254a, the pad 256, the conductive element 260, the flange R2, and the end E2 are configured and operated in a manner similar to that of the substrate 110, the arc surface 110a, the glue discharging groove 110b, the image sensing device 120, the glue layer 130, the conductive structure 150, the conductive trace 152, the conductive via 154, the pad 154a, the pad 156, the conductive element 160, the flange R1, and the end E1 in fig. 1A, and are not repeated herein. The image sensor 200 is different from the image sensor 100 in that the image sensor 200 is not disposed with the cover 140 for covering the image sensing element 120 and the adhesive layer 130 as shown in fig. 1A.

Fig. 3A is a cross-sectional view of an image sensor according to another embodiment of the invention. In the embodiment shown in fig. 3A, the substrate 310, the arc surface 310a, the glue discharging groove 310b, the image sensing device 320, the glue layer 330, the cover 340, the conductive structure 350, the conductive trace 352, the conductive via 354, the pad 354a, the pad 356, the conductive element 360, the flange R3, and the terminal E3 are configured and operated in a manner similar to that of the substrate 110, the arc surface 110a, the glue discharging groove 110b, the image sensing device 120, the glue layer 130, the cover 140, the conductive structure 150, the conductive trace 152, the conductive via 154, the pad 154a, the pad 156, the conductive element 160, the flange R1, and the terminal E1 in fig. 1A, and thus, the configuration and operation thereof are not repeated herein. The difference between the image sensor 300 and the image sensor 100 is that the conductive element 360 is not a conductive bump as the conductive element 160 in fig. 1A, the conductive element 360 is Anisotropic Conductive Film (ACF), so that the two pads 356 are not electrically connected to each other due to the anisotropic conductive property, and the image sensor 300 is electrically connected to the two pads 356 through the anisotropic conductive film.

The following will describe a method for manufacturing an image sensor according to an embodiment of the present invention by taking the image sensor 300 shown in fig. 3A as an example. Fig. 3B to 3E are flow charts of a method for manufacturing an image sensor according to an embodiment of the invention. First, as shown in fig. 3B, a substrate 310 is provided, the substrate 310 having a curved surface 310 a. Next, as shown in fig. 3C, a cover 340, an adhesive layer 330 'and an image sensor 320 are provided, wherein the adhesive layer 330' is, for example, a non-conductive film (NCF), but the invention is not limited thereto. Then, as shown in fig. 3D, the adhesive layer 330' is bonded between the cover 340 and the image sensor 320.

Finally, as shown in fig. 3E, the combined cover 340, adhesive layer 330 ' and image sensor 320 are aligned on the substrate 310, and the cover 340, adhesive layer 330 ' and image sensor 320 are pressed onto the substrate 310 to form the state shown in fig. 3A, such that the image sensor 320 is bent along with the arc surface 310a of the substrate 310 by pushing the adhesive layer 330 ', and the adhesive layer 330 covers the image sensor 320. In this process, the image sensing device 320 is bent to make the curvature of the image sensing device 320 equal to the curvature of the arc surface 310a, the image sensing device 320 is positioned in the positioning recess formed by the end E3 of the flange R3, so that the bottom surface of the image sensing device 320 is completely supported by the arc surface 310a, the image sensing device 320 and the pad 356 of the conductive structure are electrically connected to each other through the conductive element 360, the adhesive layer 330 is filled in the groove of the substrate 310, and the image sensing device 320 and the adhesive layer 330 are covered by the cover 340. In addition, after the cover 340, the adhesive layer 330 and the image sensor 320 are pressed onto the substrate 310, the cover 340 may be removed, which is not limited in the present invention. The non-bonded adhesive layers in fig. 3C to 3E are denoted by reference numeral 330', and the adhesive layers in fig. 3A that are bonded and filled in the grooves of the substrate 310 are denoted by reference numeral 330. In the present embodiment, the material of the image sensor 320 may include silicon, the thickness of the image sensor 320 is less than 200 μm, and the bonding temperature of the image sensor 320 is 100 to 200 ℃, but the invention is not limited thereto.

Fig. 3F is a graph showing changes in ambient pressure, pressing force, and temperature in the manufacturing process of the image sensor of fig. 3A. In fig. 3F, the vertical axes of the line segments a1, a2, A3 represent ambient pressure, pressing force, and temperature, respectively, and the horizontal axis represents time. Referring to fig. 3F, in more detail, before the cover 340, the adhesive layer 330 and the image sensor 320 are bonded to the substrate 310, the operating environment is in a vacuum state at time t 1. Then, the cover 340, the adhesive layer 330' and the image sensor 320 start to contact the substrate 310 at time t2, and the pressing force is gradually increased. The temperature is raised at time t3 to heat the adhesive layer 330 'to melt and fill the grooves of the substrate 310, and the melted adhesive layer 330' is partially moved away from the curved surface 310a along the adhesive discharge groove 310 b. Further temperature increase is started at time t4 to heat the conductive element 360 (anisotropic conductive adhesive) to melt and electrically connect to the image sensor 320 and the conductive structure 350. At time t5, the process environment is returned from a vacuum state to a non-vacuum state. The temperature is decreased at time t6 to cool the molten adhesive layer 330 to solidify and cover the image sensing device 320. The application of the pressing force is stopped at time t7 to complete the fabrication of the image sensor 300.

Fig. 4 is a cross-sectional view of an image sensor according to another embodiment of the invention. In the embodiment shown in fig. 4, the substrate 410, the arc surface 410a, the glue discharging groove 410b, the image sensing device 420, the glue layer 430, the cover 440, the pad 456, the conductive device 460, the flange R4, and the end E4 are configured and operated in a manner similar to that of the substrate 110, the arc surface 110a, the glue discharging groove 110b, the image sensing device 120, the glue layer 130, the cover 140, the pad 156, the conductive device 160, the flange R1, and the end E1 shown in fig. 1A, and are not described herein again. The difference between the image sensor 400 and the image sensor 100 is that the two conductive vias 454 of the conductive structure are directly connected to the two pads 460 and penetrate from the inner side of the arc surface 410a to the lower side of the substrate 410, but the invention is not limited thereto.

Fig. 5 shows a cover, an adhesive layer and an image sensor device according to another embodiment of the invention. The configuration and operation of the cover 540, the adhesive layer 530, the image sensor 520 and the conductive element 560 shown in fig. 5 are similar to the configuration and operation of the cover 340, the adhesive layer 330, the image sensor 320 and the conductive element 360 shown in fig. 3D, and are not repeated herein. The embodiment shown in fig. 5 is different from the embodiment shown in fig. 3D in that the glue layer 530' not yet laminated to the substrate has a protruding portion 532 corresponding to the image sensor 520, so that the image sensor 520 is more reliably laminated to the substrate through the protruding portion 532.

In summary, in the image sensor of the present invention, the arc surface of the substrate is provided with an adhesive layer for covering the image sensing element in addition to the image sensing element. Therefore, in the process of pressing the image sensing element and the adhesive layer onto the cambered surface of the substrate, the image sensing element can be bent along with the cambered surface by pushing the image sensing element through the adhesive layer. Because the image sensing element is not bent by air extraction as mentioned above, the invention does not need to form a through hole for air extraction at the cambered surface of the substrate as the traditional manufacturing process, thereby simplifying the manufacturing process and saving the manufacturing cost. In addition, the substrate of the present invention does not need to form a through hole as mentioned above, so the structure of the substrate is complete and the image sensing device can be stably supported. Furthermore, the image sensing element is coated by the adhesive layer, so that foreign matters can be prevented from being attached to the image sensing element in the manufacturing process.

Although the present invention has been described with reference to the above embodiments, it should be understood that the invention is not limited thereto, and that various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. An image sensor, comprising:

a substrate having a curved surface;

the image sensing element is arranged on the cambered surface, wherein the image sensing element bends along with the cambered surface; and

a glue layer disposed on the arc surface and covering the image sensor,

the cambered surface is provided with a plurality of flanges surrounding the image sensing element, the tail ends of the flanges surround the image sensing element to form a positioning concave part, and the image sensing element is positioned in the positioning concave part.

2. The image sensor as claimed in claim 1, wherein the curvature of the image sensor element is the same as the curvature of the curved surface.

3. The image sensor as claimed in claim 1, comprising a cover, wherein the cover is disposed on the substrate and covers the image sensor and the adhesive layer.

4. The image sensor as claimed in claim 3, wherein the maximum distance between the top surface of the image sensor and the cover is smaller than the thickness of the cover.

5. The image sensor as claimed in claim 1, wherein the curved surface is a concave curved surface to form a groove on the substrate.

6. The image sensor as claimed in claim 5, wherein the adhesive layer is filled in the recess.

7. The image sensor as claimed in claim 1, wherein the substrate has no through-hole at the curved surface.

8. The image sensor as claimed in claim 1, wherein the substrate has at least one row of glue grooves extending from the periphery of the image sensor to the edge of the curved surface.

9. The image sensor as claimed in claim 8, wherein the at least one row of glue grooves is plural, and the plurality of flanges are arranged at intervals to form the plurality of rows of glue grooves.

10. The image sensor as claimed in claim 1, comprising a conductive structure, wherein the conductive structure is disposed on the substrate and electrically connected to the image sensor device, and extends from below the image sensor device to outside the arc surface.

11. The image sensor as claimed in claim 10, wherein the substrate has an upper side and a lower side opposite to each other, the arc is located on the upper side of the substrate, and the conductive structure penetrates from inside or outside the arc to the lower side of the substrate.

12. The image sensor of claim 10, wherein the conductive structure comprises at least one of a conductive via and a conductive trace.

13. The image sensor as claimed in claim 10, comprising at least one conductive element, wherein the conductive element is disposed between the image sensor and the curved surface and electrically connects the image sensor and the conductive structure.

14. The image sensor as claimed in claim 13, wherein the conductive element is a conductive bump or an anisotropic conductive adhesive.

15. The image sensor as claimed in claim 8, comprising a conductive structure, wherein the conductive structure extends along the glue discharging groove to outside the arc surface.