CN211557372U

CN211557372U - Image sensor

Info

Publication number: CN211557372U
Application number: CN202020330265.9U
Authority: CN
Inventors: 黄景煜; 郑铭媛; 王仲益; 林郁轩
Original assignee: Shenya Technology Co ltd
Current assignee: Egis Technology Inc
Priority date: 2019-08-22
Filing date: 2020-03-17
Publication date: 2020-09-22
Anticipated expiration: 2030-03-17
Also published as: WO2021031557A1; CN111246132A; TW202109859A

Abstract

The utility model provides an image sensor, including image sensing chip and first metal wiring layer. The image sensing chip has an upper surface including a sensing surface. The first metal connecting line layer is arranged on the upper surface and is used for electrically connecting the image sensing chip to the control circuit. The first metal connecting line layer is provided with at least one opening above the sensing surface to form a filter. A method for manufacturing the image sensor is also provided.

Description

Image sensor

Technical Field

The utility model relates to a sensor, and especially relate to an image sensor.

Background

The filter is one of the devices commonly used in image sensors, for example, the filter is applied to an image sensor chip to filter out background noise light (e.g., infrared light). Conventional optical filters are typically fabricated with multiple optical coatings. However, this process technology is costly, takes a long time to manufacture, and requires special equipment to complete.

Due to the development of smart phones and mobile devices, the use requirements of the image sensor are greatly increased. Generally, the yield of semiconductor processes for fabricating image sensor chips is much greater than that of conventional optical filters. Therefore, in the case where the manufacturing time of the conventional optical filter cannot be further shortened, the productivity of the filter is difficult to match the yield of the image sensor chip.

SUMMERY OF THE UTILITY MODEL

The utility model relates to an image sensor, it can shorten manufacturing time, and the cost is lower.

The utility model discloses an image sensor of an embodiment includes image sensing chip and first metal wiring layer. The image sensing chip has an upper surface including a sensing surface. The first metal connecting line layer is arranged on the upper surface and is used for electrically connecting the image sensing chip to the control circuit. The first metal connecting line layer is provided with at least one opening above the sensing surface to form a filter.

In an embodiment of the present invention, the image sensor further includes at least one second metal wiring layer disposed on the upper surface, wherein at least one of the second metal wiring layers is disposed between the image sensor chip and the first metal wiring layer.

In an embodiment of the present invention, the at least one opening is a slit.

In an embodiment of the present invention, the at least one opening is a plurality of openings, and the openings are parallel to each other.

In an embodiment of the present invention, the at least one opening is a hole.

In an embodiment of the present invention, the at least one opening is a plurality of openings, and the openings are arranged in an array.

In an embodiment of the present invention, the filter is a band pass filter, and the width of the at least one opening is less than or equal to half of the maximum value of the wavelength to be retained, and greater than or equal to half of the minimum value of the wavelength to be retained.

In an embodiment of the present invention, the filter is a short-pass filter, and the width of the at least one opening is less than or equal to half of a maximum value of the wavelength to be retained.

In an embodiment of the present invention, the first metal wiring layer and the second metal wiring layer are made of the same material.

In an embodiment of the present invention, the second metal wiring layer is disposed between the image sensor chip and the first metal wiring layer.

Based on the foregoing, because the utility model discloses image sensor directly forms first metal wiring layer on the sensing face of image sensing chip, consequently, the utility model discloses image sensor can shorten the manufacturing time, and the cost is lower, and is favorable to manufacturing in a large number and less not be limited to the problem that the productivity is not enough.

Drawings

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

Fig. 1 is a schematic cross-sectional view of an image sensor according to an embodiment of the present invention.

Fig. 2 is a partially enlarged view of the filter of fig. 1.

Fig. 3 is a graph of transmittance of the filter versus opening width at an optical wavelength of 500 nanometers (green light) and an incident angle of 0 degrees.

Fig. 4 is a graph of transmittance of the filter versus opening width at a light wavelength of 700 nanometers (red light) and an angle of incidence of 0 degrees.

Fig. 5 is a graph of the transmittance of the filter at 700 nm divided by the transmittance of the filter at 500 nm versus the angle of incidence for a first metal wiring layer having an opening width of 0.3 μm.

Fig. 6 is a flowchart of a method for manufacturing an image sensor according to an embodiment of the present invention.

Description of the reference numerals

10: image sensing chip

11: upper surface of

12: sensing surface

20: filter with a filter element having a plurality of filter elements

30: control circuit

40: transparent filler

100: metal connecting wire layer

101: first metal connecting line layer

102. 103, 104, 105: second metal wiring layer

A: region(s)

d 1: width of

d 2: distance between two adjacent plates

h: thickness of

O: opening of the container

P: pitch of

S100, S120: step (ii) of

Detailed Description

Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the description to refer to the same or like parts.

Fig. 1 is a schematic diagram of an image sensor according to an embodiment of the present invention. Referring to fig. 1, an image sensor according to an embodiment of the present invention includes an image sensor chip 10 and a metal interconnection layer 100. The image sensor chip 10 is, for example, a Complementary Metal Oxide Semiconductor (CMOS) image sensor chip, but the present invention is not limited thereto. In other embodiments, the image sensor chip 10 may also be a Charge Coupled Device (CCD) chip. The region a of the upper surface 11 of the image sensor chip 10 is a sensing surface 12. The metal wiring layer 100 is disposed on the upper surface 11 for electrically connecting the image sensor chip 10 to the control circuit 30. In the present embodiment, the metal wiring layer 100 includes a first metal wiring layer 101 and second

metal wiring layers

102, 103, 104, 105. Fig. 1 simply illustrates four second

metal wiring layers

102, 103, 104, 105, however, the number of the metal wiring layers 100 depends on the design requirement, and the invention is not limited thereto. The first metal wiring layer 101 has at least one opening O above the sensing surface 12 to form the filter 20.

That is, the image sensor chip 10 may be formed by a semiconductor process, and then the metal interconnection layer 100 may be formed on the sensing surface 12 of the image sensor chip 10 by a semiconductor process (e.g., a photolithography process). Therefore, in the embodiment of the present invention, the filter 20 can be formed by a semiconductor process using the same manufacturing equipment as the image sensor chip 10. Taking the photolithography process as an example, the production of the filter 20 according to the embodiment of the present invention is not limited by the problem of insufficient productivity because it is favorable for mass production.

In detail, at least one of the second metal wire layers 102, 103, 104, and 105 of the present embodiment is disposed between the image sensor chip 10 and the first metal wire layer 101. In fig. 1, the second metal wire layers 102, 103, 104, 105 are all disposed between the image sensor chip 10 and the first metal wire layer 101, and the first metal wire layer 101 forming the filter 20 is the one of the metal wire layers 100 that is farthest from the image sensor chip 10. The distance between the first metal wire layer 101 and the image sensor chip 10 is d2, and the distance d2 is equal to 5 micrometers, for example, but the invention is not limited thereto.

In addition, in the present embodiment, the first metal wiring layer 101 and the second metal wiring layers 102, 103, 104, and 105 may be made of the same material. However, the present invention is not limited thereto, and the material of each layer of the metal wiring layer 100 should be determined according to the design requirement.

Fig. 2 is a partially enlarged view of the filter of fig. 1. Referring to fig. 1 and fig. 2, in fig. 2, the openings O may be slits, and the openings O are parallel to each other. In one embodiment, the opening O may be a hole, and a plurality of openings O may be arranged in an array. In another embodiment, the filter 20 may have only one opening O. However, the present invention is not limited thereto, and the number and shape of the openings O are determined by the overall design of the image sensor.

In the present embodiment, when the filter 20 is designed as a Band-pass filter (Band-pass filter), the width d1 of the opening O can be designed to be less than or equal to half of the maximum value of the wavelength to be reserved and greater than or equal to half of the minimum value of the wavelength to be reserved. When the filter 20 is designed as a short (wavelength) pass filter (i.e. high frequency signal can pass), the width d1 of the opening O can be designed to be less than or equal to half of the maximum value of the reserved wavelength. For example, the width d1 of the opening O falls within the range of 0.1 to 1 micron, and the thickness h of the opening O (or each layer of the metal wiring layer 100) is equal to 0.5 micron. Further, the pitch P between the openings O is equal to 1.5 micrometers.

Besides, in the present embodiment, the transparent filler 40 may be disposed between the first metal wiring layer 101 and the image sensing chip 10, and similarly, the transparent filler 40 may be disposed between the first metal wiring layer 101 and the control circuit 30, or alternatively, the transparent filler 40 may be disposed between the image sensing chip 10 and the control circuit 30. The transparent filler 40 may be disposed between the adjacent first and second metal wiring layers 101, 102, 103, 104, 105 and within the opening O of the first metal wiring layer 101. The transparent filler 40 may be a transparent insulating material, such as Silicon dioxide (Silicon dioxide).

Based on the above, because the first metal wiring layer 101 of the embodiment of the present invention can be used as the connection line between the image sensor chip 10 and the control circuit 30, and the first metal wiring layer 101 has the opening O above the sensing surface 12. Therefore, the first metal wiring layer 101 can function as a filter by the design of the connection line. Compared with a filter which forms an optical film in a film coating mode, the image sensor provided by the embodiment of the utility model has the advantages of lower cost, and is beneficial to mass production and is not limited by the problem of insufficient productivity.

Fig. 3 is a graph of transmittance of the filter versus opening width at an optical wavelength of 500 nanometers (green light) and an incident angle of 0 degrees. In fig. 3, the horizontal axis represents the opening O width d1, and the vertical axis represents the transmittance. Referring to fig. 3, if the maximum value of the reserved wavelength is 500 nm, the width d1 of the opening O of the first metal wiring layer 101 is preferably less than or equal to 0.25 μm.

Fig. 4 is a graph of transmittance of the filter versus opening width at a light wavelength of 700 nanometers (red light) and an angle of incidence of 0 degrees. In fig. 4, the horizontal axis represents the opening O width d1, and the vertical axis represents the transmittance. Referring to fig. 4, if the maximum value of the reserved wavelength is 700 nm, the width d1 of the opening O of the first metal wiring layer 101 is preferably less than or equal to 0.35 μm.

Fig. 5 is a graph of the transmittance of the filter at 700 nm divided by the transmittance of the filter at 500 nm versus the angle of incidence for a first metal wiring layer having an opening width of 0.3 μm. As shown in fig. 5, when the width d1 of the opening O is 0.3 μm, the green light of 500 nm has better transmittance, and the transmittance of the red light of 700 nm is only 40% to 50% of the transmittance of the green light of 500 nm. Furthermore, referring to fig. 3, fig. 4 and fig. 5, when the wavelength of light is larger than 700 nm, such as infrared light, the transmittance is lower. In other words, when the width d1 of the opening O of the first metal wiring layer 101 is smaller than or equal to 0.3 μm, the filter 20 of the embodiment of the present invention can be used as an infrared cut filter.

Fig. 6 is a flowchart of a method for manufacturing an image sensor according to an embodiment of the present invention. Referring to fig. 1 and fig. 6, a method for manufacturing an image sensor according to an embodiment of the present invention includes the following steps. In step S100, the image sensor chip 10 is formed by a semiconductor process. Next, in step S120, a first metal interconnection layer 101 is formed on the upper surface 11 of the image sensing chip 10 by using a semiconductor process, and the image sensing chip 10 is electrically connected to the control circuit 30 through the first metal interconnection layer 101. The first metal interconnection layer 101 has at least one opening O above the sensing surface 12 included in the upper surface 11 of the image sensor chip 10 to form the filter 20.

In summary, since the image sensor and the manufacturing method thereof according to the embodiment of the present invention have the opening above the sensing surface on the first metal wiring layer, the first metal wiring layer can have the function of the filter. Furthermore, because the image sensor and the manufacturing method thereof according to the present invention directly form the first metal interconnection layer by the semiconductor process on the sensing surface of the image sensor chip, the image sensor and the manufacturing method thereof according to the present invention can shorten the manufacturing time, reduce the cost, and facilitate mass manufacturing without being limited by the problem of insufficient productivity.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims

1. An image sensor, comprising:

the image sensing chip is provided with an upper surface comprising a sensing surface; and

the first metal connecting line layer is configured on the upper surface and used for electrically connecting the image sensing chip to the control circuit, wherein the first metal connecting line layer is provided with at least one opening above the sensing surface to form a filter.

2. The image sensor of claim 1, further comprising at least one second metal wiring layer disposed on the top surface, at least one of the at least one second metal wiring layer being disposed between the image sensor chip and the first metal wiring layer.

3. The image sensor of claim 1, wherein the at least one opening is a slit.

4. The image sensor of claim 1, wherein the at least one opening is a plurality of openings, and the plurality of openings are parallel to each other.

5. The image sensor of claim 1, wherein the at least one opening is a hole.

6. The image sensor of claim 1, wherein the at least one opening is a plurality of openings arranged in an array.

7. The image sensor of claim 1, wherein the filter is a band-pass filter, and the width of the at least one opening is equal to or less than half of the maximum value of the wavelength to be retained and equal to or more than half of the minimum value of the wavelength to be retained.

8. The image sensor of claim 1, wherein the filter is a short pass filter and the width of the at least one opening is less than or equal to half of a maximum of a wavelength to be retained.

9. The image sensor of claim 2, wherein the first metal wiring layer and the at least one second metal wiring layer are made of the same material.

10. The image sensor of claim 2, wherein the at least one second metal wiring layer is disposed between the image sensor chip and the first metal wiring layer.