CN117092045A - Micro spectrum sensor chip, preparation method thereof and micro spectrometer - Google Patents

Abstract

The application relates to the field of photonic devices, and particularly discloses a miniature spectrum sensor chip, a preparation method thereof and a miniature spectrometer. The micro spectrum sensor chip comprises an optical filter, an optical device and an electronic component, wherein the optical device is used for receiving light transmitted through the optical filter. Compared with the optical elements in the traditional spectrometer, the micro-spectrum sensor chip of the application adopts the semiconductor micro-nano processing technology to prepare the required super-surface optical filter, greatly reduces the volume of the micro-spectrum sensor chip, and also avoids a series of problems of increased device volume, high processing cost, errors caused by the cascade use of a plurality of optical elements, and the like.

Description

Micro spectrum sensor chip, preparation method thereof and micro spectrometer

Technical Field

The application belongs to the field of photonic devices, and particularly relates to a miniature spectrum sensor chip, a preparation method thereof and a miniature spectrometer.

Background

In recent years, spectrum detection technology has entered into daily life of people, and in many situations, spectrum detection can bring great convenience to life of people, for example, the spectrum detection technology can be integrated into a mobile phone to detect residues of laundry detergent on clothes, whether harmful chemical components are in food, color temperature balance during photographing, harmful gas residues in new houses and the like.

Multispectral detection also plays a vital role in many areas of professional technology, such as target identification in the military field, crop monitoring in the agricultural field, geological surveys, medical diagnostics, and so forth, relative to traditional spectroscopic detection techniques. Compared with the traditional spectrum detection, the multispectral detection data not only contains spectrum information, but also contains imaging information, and the multispectral detection data combines spectrum and image information, so that the multispectral detection data can cope with occasions with various different requirements.

With the continuous development of the spectroscopic technology, the spectrometers and the multispectral sensors are gradually developed to be miniaturized, and the development of the micro-lens technology greatly reduces the volume of the optical element, so that the desk type spectrometers are gradually developed into the handheld spectrometers with the sizes of the playing cards at present. In the same way, the current multispectral sensor acquires multispectral images mostly based on the mode of switching optical filters, but the acquisition mode of the multispectral images needs the matching use of a plurality of groups of optical filters, and meanwhile, the time-sharing acquisition mode can cause low definition and acquisition efficiency of the multispectral images. Disclosure of Invention

The application provides a miniature spectrum sensor chip, a preparation method thereof and a miniature spectrometer, which at least solve the technical problems in the prior art.

The application provides a miniature spectrum sensor chip which comprises an optical filter, an optical device and an electronic component, wherein the optical device is used for receiving light transmitted through the optical filter.

In one embodiment, the optical filter is comprised of a functional layer obtained by semiconductor processing techniques on a substrate transparent to the visible light band.

In one embodiment, the functional layer is a super surface structure or a photonic band gap structure or a refractive index adjustable phase change material or a multilayer thin film structure.

In one embodiment, the multi-layer thin film structure is formed by overlapping a tin indium oxide thin film and a phase change material thin film for a plurality of times; the functional layers of other structures except the multilayer thin film structure are made of one or more materials selected from silicon nitride, amorphous silicon, titanium dioxide and a chalcogenide material.

In one embodiment, the optical filter includes at least one set of filter groups, each set of filter groups containing therein an array of filters that allow the passage of a particular narrowband band.

In one embodiment, the micro-nano structure of the filter array of each of the filter banks selects a multiple rotational symmetry structure.

In one embodiment, the array of subsurface filters is an m n array, where m, n > 1, allowing electromagnetic waves of various bands in the 300nm-2000nm range to pass.

In one embodiment, the electronic components include a gain, a data selector, an analog-to-digital converter, transmit and receive buffers, an I2C interface, and pins.

The application also provides a preparation method of the micro spectrum sensor chip, which comprises the following preparation steps:

s1, growing a layer of transparent substrate at a preset selected wave band by adopting chemical vapor deposition above a photosensitive pixel of an optical device at a wafer level;

s2, etching a micro-nano structure with a specific size on a substrate by adopting a photoetching technology to manufacture an optical filter allowing specific wavelength to pass through;

and S3, thinning the substrate of the optical filter, and packaging the substrate, glass, the circuit structure and the wiring pins by using an adhesive to obtain the micro spectrum sensor chip.

The application also provides a micro spectrometer, which comprises any micro spectrum sensor chip.

The application has the following advantages:

1. the requirements of larger detection scenes are met, the micro-nano processing technology is adopted, and the ultra-surface spectrometer is prepared and miniaturized to be integrated with a chip by utilizing the extremely large light field regulation capability and extremely small volume of the ultra-surface and the characteristics of compatible semiconductor technology;

2. compared with the optical elements in the traditional spectrometer, the volume of the ultra-surface lens is greatly reduced by adopting the semiconductor micro-nano processing technology, and a series of problems of increased device volume, high processing cost, errors caused by assembling instability and the like caused by cascade use of various optical elements are avoided.

Drawings

FIG. 1 is a structural frame diagram of a miniature spectrum sensor chip;

FIG. 2 is a cross-sectional view of a micro spectrum sensor chip in example 1;

FIG. 3 is a process flow diagram of the micro spectrum sensor chip of example 1;

FIG. 4 is a schematic diagram of three forms of functional layers in example 1;

FIG. 5 is a schematic diagram of the filtering effect of the cylindrical micro-nano structure in example 1;

FIG. 6 is a schematic diagram of the filtering effect of the cylindrical micro-nano structure in example 1;

FIG. 7 is a schematic diagram of the filtering effect of the cylindrical micro-nano structure in example 1;

FIG. 8 is a cross-sectional view of a micro spectrum sensor chip in example 2;

FIG. 9 is a cross-sectional view of a micro spectrum sensor chip in example 3;

in the figure: 11. glass; 12. an optical filter; 13. a photodetector; 14. a substrate; 15. an adhesive; 16. a wiring pin; 17. a super surface lens; 21. a cylindrical supersurface structure; 22. a cross-shaped supersurface structure; 23. a phase change material with an adjustable refractive index; 24. a multilayer film structure.

Detailed Description

The present application will be described in further detail with reference to the accompanying drawings.

With the continuous advancement of the spectrum detection field, in order to meet the requirement of larger detection scenes, the inventor adopts a micro-nano processing technology, utilizes the extremely large light field regulation capability and extremely small volume of the super surface and the characteristics of compatible semiconductor technology to prepare the super surface type spectrometer, and miniaturizes the super surface type spectrometer to be integrated with a chip, so that the formation of a brand new spectrum detection chip becomes possible. Meanwhile, the semiconductor micro-nano processing technology is adopted to prepare the required super-surface lens, compared with the optical elements in the traditional spectrometer, the volume of the super-surface lens is greatly reduced, and the problems of increased device volume, high processing cost, errors caused by assembling instability and the like caused by cascade use of various optical elements are avoided.

Referring to fig. 1, a micro spectrum sensor chip includes an optical filter, an optical device, and an electronic component.

Wherein the optical device is a photodetector Array (PD, array) or a CIS chip (CMOS image sensor), and the optical device is used for receiving the light transmitted through the super surface filter.

The electronic components include gain (gain), data selector (Mux, multiplexer), analog-to-digital converter (ADC, analog to Digital Converter), transmit buffer (FIFO Tx) and receive buffer (FIFO Rx), I2C interface (I2C interface), and other various electronic interfaces, pins (VDD refers to the operating voltage of the chip, SCL refers to Structured Control Language structured control language, SDA refers to the data signal line of the I2C bus, INT refers to input, GPIO refers to General-purpose input output General-purpose input/output, GND refers to ground), and the like.

The optical filter is composed of a functional layer obtained by adopting a semiconductor processing technology on a substrate transparent to the visible light wave band, and the functional layer can be any one of a super-surface structure, a photonic band gap structure, a phase change material with adjustable refractive index or a multilayer film structure. The multi-layer film structure is formed by overlapping a tin indium oxide film and a phase change material film for a plurality of times, and other functional layers except the multi-layer film structure are made of one or more materials selected from silicon nitride, amorphous silicon, titanium dioxide and a chalcogenide material.

The optical filter comprises at least one group of filter groups, each group of filter groups comprises a filter array which allows specific narrow-band wave bands to pass through, and commonly used arrays are 2 x 2,3 x 3,4 x 4 … … m n and the like, and one filter group is formed by narrow-band filter arrays of m rows and n columns and allows electromagnetic waves of various wave bands such as 300nm-2000nm to pass through. For monolithic filters, i.e. when the filter group has only one group, the micro-nano structure prepared thereon selects in principle multiple rotational symmetry structures, such as cylinders, rings, concentric rings, circular nanopores, square nanopores, cross nanopores, etc. in order to ensure that it is insensitive to the polarization of the external incident light, wherein the size of the micro-nano structure is determined by the selected transmission wavelength.

External light is incident to the filter group, specific spectrum filtered by the filter is incident to a designated area of the image sensor, electromagnetic waves of the specific spectrum are received by the image sensor and then converted into corresponding electric signals, the signals are amplified by a gain circuit, any circuit is selected according to requirements through a data selector (Mux), the selected analog signals are converted into digital signals through an analog-digital selector (ADC), and the digital spectrum signals are output by a transmitting buffer (FIFO Tx), a receiving buffer (FIFO Rx) and an I2C interface. The subsequent PD array or CIS chips and read circuitry described above may be fabricated and packaged on the same using well-established CMOS wafer processing techniques to form the micro-spectrum sensor chip.

Example 1

Referring to fig. 2, the micro spectrum sensor chip includes glass 11, an optical filter 12, a photodetector array 13, a substrate 14, an adhesive 15, and a wire lead 16, and the glass 11, the optical filter 12, the photodetector array 13, and the substrate 14 are fixed by the adhesive 15.

The preparation method of the micro spectrum sensor chip comprises the following steps:

above the photosensitive pixels of the wafer-level photodetector array 13, a layer of transparent substrate in a preset selected wave band is grown by chemical vapor deposition, the material of the substrate can be selected from visible light to near infrared transparent materials, such as silicon nitride, amorphous silicon, titanium dioxide, various chalcogenide materials and the like, a micro-nano structure with a specific size is etched on the substrate by adopting a photoetching technology to manufacture an optical filter 12 allowing specific wavelength to pass through, different arrangement modes of the micro-nano structure with different sizes result in that the filter arrays allowing different specific wave bands to pass through form a filter set, the wave band through which the whole filter set runs is 300-2000nm, and the wave band through which a single filter can allow to pass is determined by the array dimension of the filter. After the preparation of the optical filter array is completed, the substrate 14 is thinned, and then the prepared product, the glass 11, the circuit structure and the wiring pins 16 are packaged by using the adhesive 15 to form the micro spectrum sensor chip required by us, wherein the adhesive 15 can be glass adhesive.

In the micro-spectrum sensor chip, besides etching the micro-nano structure by using etching equipment, the optical filter array can also selectively deposit and grow phase change material with adjustable refractive index, or physical vapor deposition or spin coating multilayer film material, and the schematic diagram is shown in the following figure 4, wherein a cylindrical micro-nano structure array 21 and a cross micro-nano structure array 22 grow and etch on the photodetector array 13, and the range of the wave bands allowed to pass is adjusted by controlling the radius size of the cylinder or the size of the cross micro-nano structure; an index-adjustable phase change material 23 is deposited on the photodetector 13, which transmits a change through different doping concentrations or photo-induced material indices of refraction, adjusting the range of bands allowed to pass; a multilayer thin film structure 24 is deposited or spin coated on the photodetector array 13 that adjusts the range of bands allowed to pass through by controlling the thickness and material type of the different film layers. Under different structural situations, different filtering effects can be realized by adjusting the physical parameters, for example, fig. 5,6 and 7 are filter effect diagrams of single-chip filters in the filter set obtained by adjusting the cylindrical radius size of the cylindrical micro-nano structure, and the spectral detection effect is realized by forming the filter set by using a plurality of filters with different transmission curves.

Example 2

In the above-mentioned spectrum detection chip, the micro spectrum sensor chip may be manufactured by another method, that is, by manufacturing the filter group 12 on the glass 11, as shown in fig. 8. In the preparation process, the optical filter 12 is prepared on the glass 11 towards one side of the photodetector array 13 by micro-nano processing technology, and then is packaged with the photodetector array 13 to obtain the micro spectrum sensor chip.

Example 3

Referring to fig. 9, a layer of super surface lens 17 can be processed above the optical filter 12, the light collecting capability of the super surface lens 17 is utilized to improve the receiving capability of the spectrum sensor chip to the incident light, meanwhile, the ultra-thin characteristic of the super surface and the compatibility characteristic of the semiconductor material enable the super surface processing to be continuously deposited and etched after the preparation of the optical filter set is completed, and the super surface lens 17 with a preset focal length is prepared above the optical filter 12. The optical filter plate group and the super-surface lens are directly processed and prepared on the wafer-level image sensor to form an integral micro spectrum sensor chip.

In the above micro spectrum sensor chip, as shown in fig. 9, by preparing the super surface lens 17 on the glass 11, in the above preparation process, the glass window for encapsulation is replaced by the super surface lens, and the super surface lens 17 faces the optical filter 12, and in the design process, according to the focal length and phase distribution formula of the super surface:

wherein x and y are super atomic coordinates of the wide-angle super lens,for oblique incidence beam and incidence angles of x-axis and y-axis, f is focal length of designed wide-angle super lens, lambda is incident light wavelength, +.>，/>。

And calculating to obtain the phase distribution condition of each position of the super surface, and determining the size radius of the micro-nano structure of each position of the super surface structure by combining the corresponding relation between the micro-nano structure size and the phase. The ultra-surface structure is etched in materials (such as silicon nitride, amorphous silicon, titanium dioxide, various chalcogenide materials and the like) transparent to visible light and near infrared bands through a photoetching technology, and then the ultra-surface structure is packaged in a miniature spectrum sensor chip instead of a glass window in the packaging process, so that the spectrum detection capability is improved.

The preparation method of the micro spectrum sensor chip comprises the following steps:

s1, preparing a functional layer

Growing a layer of transparent substrate at a preset selected wave band above the photosensitive pixels of the wafer-level photoelectric detector by adopting chemical vapor deposition;

the material of the substrate can be selected from visible light to near infrared transparent materials, such as silicon nitride, amorphous silicon, titanium dioxide, various chalcogenide materials and the like;

s2, preparing an optical filter array

Etching a micro-nano structure with a specific size on the filter plate by adopting a photoetching technology to prepare an optical filter which allows specific wavelength to pass through;

because of different arrangement modes of the micro-nano structures with different sizes, the filter arrays with different allowed specific wave bands form a filter set, the wave band through which the filter set operates is 300-2000nm, and the wave band through which a single filter can pass is determined by the array dimension of the filter;

s3, preparing a miniature spectrum sensor chip

And thinning the substrate of the optical filter, and packaging the substrate, glass, a circuit structure and wiring pins by using an adhesive to obtain the micro spectrum sensor chip.

The application also provides a micro spectrometer, which comprises any micro spectrum sensor chip. Because the micro spectrometer adopts the micro-nano processing technology, the micro spectrometer is miniaturized to be integrated with a micro spectrum sensor chip by utilizing the extremely large light field regulation capability of the super surface, the extremely small volume and the characteristics of the compatible semiconductor technology, thereby meeting the requirement of larger detection scene.

In the description of the present specification, the descriptions of the terms "one embodiment," "some embodiments," "an implementation," "an example," "a particular example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

The foregoing is merely a specific embodiment of the disclosure, but the protection scope of the disclosure is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the disclosure, and it should be covered in the protection scope of the disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims (10)

1. A miniature spectrum sensor chip, characterized in that it comprises an optical filter, an optical device and an electronic component, wherein the optical device is used for receiving the light transmitted through the optical filter.

2. A miniature spectrum sensor chip according to claim 1, wherein: the optical filter is composed of a functional layer obtained by adopting a semiconductor processing technology on a substrate transparent to the visible light wave band.

3. A miniature spectrum sensor chip according to claim 2, characterized in that: the functional layer is a super-surface structure or a photonic band gap structure or a phase change material or a multilayer film structure with adjustable refractive index.

4. A miniature spectrum sensor chip according to claim 3, characterized in that: the multilayer film structure is formed by overlapping a tin indium oxide film and a phase change material film for a plurality of times;

the functional layers of other structures except the multilayer thin film structure are made of one or more materials selected from silicon nitride, amorphous silicon, titanium dioxide and a chalcogenide material.

5. A miniature spectrum sensor chip according to claim 1, wherein: the optical filter comprises at least one group of filter groups, and each group of filter groups comprises a filter array which allows a specific narrow-band wave band to pass through.

6. The miniature spectrum sensor chip of claim 5, wherein: the micro-nano structure prepared on the filter array of each group in the filter group selects a multiple rotation symmetry structure.

7. The miniature spectrum sensor chip of claim 5, wherein: the filter array is an m x n array, wherein m, n > 1, allowing electromagnetic waves of various wave bands in the range of 300nm-2000nm to pass.

8. A miniature spectrum sensor chip according to claim 1, wherein: the electronic components include gain, data selector, analog-to-digital converter, transmit and receive buffers, I2C interface and pins.

9. The preparation method of the micro spectrum sensor chip is characterized by comprising the following preparation steps:

s1, growing a layer of transparent substrate at a preset selected wave band by adopting chemical vapor deposition above a photosensitive pixel of an optical device at a wafer level;

s2, etching a micro-nano structure with a specific size on a substrate by adopting a photoetching technology to manufacture an optical filter allowing specific wavelength to pass through;

and S3, thinning the substrate of the optical filter, and packaging the substrate, glass, the circuit structure and the wiring pins by using an adhesive to obtain the micro spectrum sensor chip.

10. Miniature spectrum appearance, its characterized in that: comprising a miniature spectrum sensor chip of any one of 1-8.