CN115768233A - Chip support structure and preparation method thereof, pyroelectric sensor - Google Patents

Abstract

The application relates to a chip support structure, a preparation method thereof, and a pyroelectric sensor. The chip support structure includes: a base layer; a middle layer, which is arranged on the base layer; and a top layer, which is arranged on the middle layer, and the side of the top layer away from the base layer is provided with a plurality of columnar protrusion structures; each columnar protrusion A structure is used to support the heat sensitive element; wherein, the middle layer has a thermal conductivity much lower than that of the base layer and the top layer, and the top layer has a higher electrical conductivity than the middle layer. In this application, by setting the base layer, the middle layer, and the top layer, on the one hand, because the thermal conductivity of the middle layer is much lower than that of the base layer and the top layer, it is difficult for the thermal signal drawn from the top layer to pass through the middle layer with lower thermal conductivity. The heat loss is reduced accordingly, the response quality and efficiency are improved, and the detection rate and signal-to-noise ratio of the final product can also be improved; on the other hand, since the top layer has a higher conductivity than the middle layer, the top layer can conduct heat sensitive The lower electrode signal of the component.

Description

Chip support structure and preparation method thereof, pyroelectric sensor

technical field

The invention relates to the technical field of semiconductors, in particular to a chip support structure, a preparation method thereof, and a pyroelectric sensor.

Background technique

At present, the internal structure of infrared pyroelectric sensors generally includes sensitive elements, supporting structures, and PCB/ceramic substrates. The general supporting structure includes single-column support and multi-column support, and the material is generally metal, ceramic or silicon. The stability of the single support column structure is not good, and the noise interference is large; the multi-support column structure increases the contact area between the support structure and the sensitive element, resulting in a large heat loss and reducing the signal response of the sensor; in addition, the ceramic, metal or silicon As a support column, the material itself has a large thermal conductivity, which causes the heat radiation received by the pyroelectric sensor to be lost through heat conduction, reducing the signal response of the sensor.

Therefore, how to solve the above heat conduction loss is an urgent problem to be solved.

Contents of the invention

Based on this, it is necessary to provide a chip support structure to address the above problems. The chip support structure is used to support thermally sensitive components, including:

basal layer;

an intermediate layer disposed on the base layer; and

The top layer is arranged on the middle layer, and the side of the top layer facing away from the base layer is provided with a plurality of columnar protrusion structures; each of the columnar protrusion structures is used to support the heat sensitive element;

Wherein, the middle layer has a thermal conductivity much lower than that of the base layer and the top layer, and the top layer has a higher electrical conductivity than the middle layer.

The above-mentioned chip support structure, by setting the base layer, the middle layer and the top layer, on the one hand, because the thermal conductivity of the middle layer is much lower than that of the base layer and the top layer, it is difficult for the thermal signal drawn from the top layer to pass through the lower thermal conductivity. Conduction out of the middle layer with high conductivity, correspondingly reduces heat loss, improves response quality and efficiency, and can also improve the detection rate and signal-to-noise ratio of the final product; on the other hand, because the top layer has a higher conductivity than the middle layer, the top layer can be Conducting the lower electrode signal of the heat sensitive element.

In one of the embodiments, the material of the base layer is silicon.

In one embodiment, the material of the intermediate layer is silicon dioxide.

In one embodiment, the material of the top layer is highly doped silicon.

In one of the embodiments, it also includes:

The assembly hole penetrates the base layer from the surface of the middle layer.

In one of the embodiments, it also includes:

The circuit layer is disposed on the middle layer and is at least in contact with the assembly hole and/or the columnar protrusion structure.

Based on the same inventive concept, the present application also provides a chip support structure, including:

glass substrates; and

A plurality of columnar protruding structures arranged on the glass substrate; wherein, the material of the protruding structures is glass.

Based on the same inventive concept, the present application also provides a method for preparing a chip support structure, including:

providing a base layer;

forming an intermediate layer on the base layer;

forming a top layer on the middle layer; wherein the middle layer has a thermal conductivity much lower than that of the base layer and the top layer, and the top layer has a higher electrical conductivity than the middle layer;

Etching is performed on the top layer to form several columnar protrusion structures.

Based on the same inventive concept, the present application also provides a method for preparing a chip support structure, including:

providing a glass substrate, and polishing the surface of the glass substrate;

Evaporating a protective layer on the polished surface;

Coating a photoresist on the protective layer, and patterning the photoresist according to a preset pattern to expose the protective layer;

The exposed protective layer is etched, and the glass substrate is etched using the etched protective layer as a mask to form several columnar convex structures.

Based on the same inventive concept, the present application also provides a pyroelectric sensor, including:

Substrate;

A chip support structure as described in any of the foregoing; and

A heat sensitive element; wherein, the heat sensitive element is disposed on a side of the chip supporting structure provided with a columnar protrusion structure.

Description of drawings

Fig. 1 is a cross-sectional view of a chip support structure in an embodiment;

Fig. 2 is a perspective view of the chip support structure in Fig. 1;

Fig. 3 is a perspective view of the chip support structure formed on the basis of Fig. 2;

4 is a cross-sectional view of a chip support structure in another embodiment;

5 is a flowchart of a method for preparing a chip support structure in an embodiment;

FIG. 6 is a flowchart of a method for manufacturing a chip support structure in another embodiment.

Detailed ways

In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the associated drawings. Preferred embodiments of the invention are shown in the accompanying drawings. However, the present invention can be embodied in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terminology used herein in the description of the present invention is only for the purpose of describing specific embodiments, and is not intended to limit the present invention.

As described in the background of this application, at present, the internal structure of an infrared pyroelectric sensor generally includes a sensitive element, a supporting structure, and a PCB/ceramic substrate. The general supporting structure includes single-column support and multi-column support, and the material is generally metal, ceramic or silicon. The stability of the single support column structure is not good, and the noise interference is large; the multi-support column structure increases the contact area between the support structure and the sensitive element, resulting in a large heat loss and reducing the signal response of the sensor; in addition, the ceramic, metal or silicon As a support column, the material itself has a large thermal conductivity, which causes the heat radiation received by the pyroelectric sensor to be lost through heat conduction, reducing the signal response of the sensor.

Therefore, how to solve the above heat conduction loss is an urgent problem to be solved.

Based on this, the present application hopes to provide a new solution to solve the above-mentioned technical problems, and its specific composition will be described in detail in the subsequent embodiments.

Referring first to FIG. 1 , it is a schematic cross-sectional view of a chip support structure provided by the present application. The chip support structure may include a glass substrate 100a; and a plurality of columnar protrusion structures 104a disposed on the glass substrate 100a; wherein, the material of the protrusion structures 104a is glass. In other words, the raised structure 104a and the glass substrate 100a of the present application are made of the same material, and since the thermal conductivity of the glass material is lower than that of metal, ceramics and silicon, the heat loss can be reduced, and the detection rate and signal can be improved. noise ratio. Further, the glass substrate 100a and the protruding structure 104a can be integrated, that is, the chip supporting structure of the present application is obtained by etching protruding structures of corresponding size and number on the glass substrate.

Exemplarily, referring to FIG. 2 , the number of raised structures 104a can be four, and the four raised structures 104a are regularly distributed on the surface of the glass ground 100a, and a plurality of raised structures 104a can increase chip support structure and heat dissipation. The contact area of the sensitive element will not increase the heat loss at the same time.

Further, please continue to refer to FIG. 1 and FIG. 2 . The chip supporting structure in this specific embodiment may further include assembly holes 102a, the assembly holes 102a penetrate the glass substrate 100a, and are arranged on the periphery of the columnar protrusion structures 104a. The function of these mounting holes 102a is to facilitate subsequent mounting of the chip support structure on the substrate of the pyroelectric sensor. Correspondingly, the number of the mounting holes 102a can be selected and adjusted according to the structure of the substrate and actual requirements, which is not limited in the present application. Exemplarily, the number of fitting holes 102a in this specific embodiment is four, and the diameters of the fitting holes 102a are not completely the same.

Further, referring to FIG. 3 , the chip supporting structure of the present application may further include a circuit layer 106a, which is disposed on the surface of the glass substrate 100a and is in contact with the assembly hole 102a and the protruding structure 104a respectively. The circuit layer 106a is mainly used for conducting electricity, so that the integrated design of the chip support structure and the circuit substrate can be completed. Compared with the traditional design in which the support structure and the circuit substrate are separated, the integrated support structure has higher stability, which can significantly reduce the noise signal, and through the integrated structural design, the assembly process of the support structure is simplified, and the reliability of the device is improved. Integration.

Based on the same inventive concept, please refer to FIG. 4 , which is a schematic cross-sectional view of a chip supporting structure in another embodiment provided by the present application. The chip supporting structure is used to support thermal sensitive elements (not shown), including a base layer 100b, a middle layer 104b and a top layer (not shown); wherein, the middle layer 104b and the top layer 1 are sequentially arranged on the base layer 100b. And the side of the top layer away from the base layer 100b is provided with several columnar protrusion structures 106b; each columnar protrusion structure 106b is used to support the thermal sensitive element;

Wherein, the middle layer 104b has a thermal conductivity much lower than that of the base layer 100b and the top layer, and the top layer has a higher electrical conductivity than the middle layer 104b.

The above-mentioned chip support structure, by setting the base layer, the middle layer and the top layer, on the one hand, because the thermal conductivity of the middle layer is much lower than that of the base layer and the top layer, it is difficult for the thermal signal drawn from the top layer to pass through the lower thermal conductivity. Conduction out of the middle layer with high conductivity, correspondingly reduces heat loss, improves response quality and efficiency, and can also improve the detection rate and signal-to-noise ratio of the final product; on the other hand, because the top layer has a higher conductivity than the middle layer, the top layer can be Conducting the lower electrode signal of the heat sensitive element.

In one embodiment, the material of the base layer 100b is silicon.

In one embodiment, the material of the intermediate layer 104b is silicon dioxide.

In one embodiment, the material of the top layer is highly doped silicon, specifically, the material of each columnar protrusion structure 106b is also highly doped silicon. It can be understood that, for the description of the arrangement positions and the arrangement quantity of the columnar protrusion structures 106b, reference may be made to the foregoing embodiments, which will not be repeated in this application.

In one embodiment, referring to FIG. 4 , the chip supporting structure of the present application may further include: an assembly hole 102 b penetrating through the base layer 100 b from the surface of the middle layer 104 b. It can be understood that the assembly holes 102b can be arranged on the periphery of the columnar protrusion structure 106b. The function of these mounting holes 102b is to facilitate subsequent mounting of the chip support structure on the substrate of the pyroelectric sensor. Correspondingly, the number of the mounting holes 102b can be selected and adjusted according to the structure of the substrate and actual requirements, which is not limited in the present application. Exemplarily, the number of fitting holes 102b in this specific embodiment is four, and the diameters of the fitting holes 102b are not completely the same.

In one embodiment, it further includes: a circuit layer (not shown in the figure), disposed on the intermediate layer 104b, and at least in contact with the assembly hole 102b and/or the columnar protrusion structure 106b. It can be understood that, for the description of the circuit layer in this specific embodiment, reference may be made to the circuit layer in the previous embodiment, and this application will not further elaborate on it.

Based on the same inventive concept, referring to FIG. 6 , the present application also provides a method for manufacturing a chip support structure, which may include steps S100b-S106b.

Step S100b, providing a base layer;

Step S102b, forming an intermediate layer on the base layer;

Step S104b, forming a top layer on the middle layer; wherein, the middle layer has a thermal conductivity much lower than that of the base layer and the top layer, and the top layer has a higher electrical conductivity than the middle layer ;

Step S106b, performing etching on the top layer to form several columnar protrusion structures.

Further, after the columnar protrusion structure is formed by etching, the above preparation method may further include the steps of:

Etching the middle layer and base layer by deep silicon etching process to obtain assembly holes;

According to the circuit design, the conductive metal is deposited on the surface of the intermediate layer to obtain the circuit layer.

Based on the same inventive concept, referring to FIG. 5 , the present application also provides a method for manufacturing a chip support structure, including steps S100a-S106a.

Step S100a, providing a glass substrate, and polishing the surface of the glass substrate;

Step S 102a, evaporating a protective layer on the polished surface;

Step S104a, coating a photoresist on the protection layer, and patterning the photoresist according to a preset pattern to expose the protection layer;

Step S106a, etching the exposed protective layer, and using the etched protective layer as a mask to etch the glass substrate to form several columnar protrusion structures.

Specifically, the above-mentioned preparation method is now described in detail:

A glass substrate with a certain thickness can be used as the substrate. The thickness of the glass substrate depends on the height of the support structure obtained by etching, and the chip support structure is prepared by a wet process;

First, the surface of the glass substrate is polished, and a protective layer is coated on the polished surface. The protective layer can be one of chromium layer, silicon nitride film or indium tin oxide, and then further protected by photoresist coating, and then Through pre-baking, exposure, development, and film hardening, the protective layer to be etched is exposed, and the etchant is prepared according to different protective layers for etching. The parameters of the etching process also vary with different etching film layers and depth requirements. And setting, after the etching is completed, clean the glass substrate and remove the photoresist;

After the protective layer is etched, the glass substrate is etched with a special glass substrate etching solution using the protective layer as a mask to form several columnar convex structures. It can be understood that the higher the concentration of the etching solution, the faster the etching speed, and the etching time depends on the etching depth. During the etching process, a water bath is used to maintain a constant temperature; for example, hydrofluoric acid, ammonium fluoride, or nitric acid and water can be used. Prepare an etching solution according to a certain concentration ratio.

The glass substrate obtained by etching, according to the requirements of the subsequent assembly process, holes are opened in the appropriate position of the glass substrate to facilitate installation to the package base;

Finally, according to the circuit design, an immersion gold process is performed on the surface as a conductive line of the glass-based circuit substrate, thereby completing the preparation of the integrated structure of the chip support and the circuit substrate.

Based on the same inventive concept, the present application also provides a pyroelectric sensor, including a substrate arranged in sequence (not shown); a chip support structure as described above; and a thermal sensitive element (not shown); Wherein, the thermal sensitive element is arranged on the side of the chip supporting structure provided with the columnar protrusion structure.

In this specific embodiment, the pyroelectric sensor can be an infrared pyroelectric sensor, and the infrared pyroelectric sensor can be widely used in fire warning and alarm, gas detection and analysis, pollution monitoring and detection, temperature difference detection, industrial production, medical treatment, etc. Electronics, spectral analysis and other fields.

Specifically, the substrate is mainly used to support the chip support structure, and the chip support structure is mainly used to support the heat sensitive element. In addition, the infrared pyroelectric sensor may also include: infrared absorbing material for improving the absorption of infrared radiation; single crystal, polymer or ceramic with pyroelectric effect; upper and lower electrodes for forming pyroelectric current.

The above-mentioned pyroelectric sensor adopts the chip support structure described in the foregoing embodiments, and on the one hand, the chip support structure has a thermal conductivity much lower than that of the base layer and the top layer on the one hand, so that the thermal signal drawn from the top layer , it is difficult to conduct through the middle layer with lower thermal conductivity, correspondingly reducing heat loss, improving response quality and efficiency, and improving the detection rate and signal-to-noise ratio of the final product; on the other hand, because the top layer has a higher thermal conductivity than the middle layer Electrical conductivity, so that the top layer can conduct the signal of the lower electrode of the thermally sensitive element.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. A chip support structure for supporting a thermally sensitive component, comprising:

a base layer;

an intermediate layer disposed on the base layer; and

the top layer is arranged on the middle layer, and a plurality of columnar protruding structures are arranged on one side, away from the substrate layer, of the top layer; each columnar protruding structure is used for supporting the heat sensitive element;

wherein the intermediate layer has a thermal conductivity much lower than the substrate layer and the top layer, and the top layer has a higher electrical conductivity than the intermediate layer.

2. The chip support structure according to claim 1, wherein the material of the base layer is silicon.

3. The chip support structure according to claim 1, wherein the material of the intermediate layer is silicon dioxide.

4. The chip support structure according to claim 1, wherein the material of the top layer is highly doped silicon.

5. The chip support structure of claim 1, further comprising:

a mounting hole extending through the base layer from a surface of the intermediate layer.

6. The chip support structure of claim 1, further comprising:

and the circuit layer is arranged on the middle layer and at least contacts with the assembly hole and/or the columnar protruding structure.

7. A chip support structure, comprising:

a glass substrate; and

the columnar bulge structures are arranged on the glass substrate; wherein, the material of the protruding structure is glass.

8. A method of making a chip support structure according to any one of claims 1 to 6, comprising:

providing a substrate layer;

forming an intermediate layer on the base layer;

forming a top layer on the middle layer; wherein the intermediate layer has a thermal conductivity much lower than the substrate layer and the top layer, and the top layer has a higher electrical conductivity than the intermediate layer;

and etching the top layer to form a plurality of columnar protruding structures.

9. A method of making the chip support structure of claim 7, comprising:

providing a glass substrate, and polishing the surface of the glass substrate;

evaporating a protective layer on the polished surface;

coating a photoresist on the protective layer, and carrying out patterning treatment on the photoresist according to a preset pattern to expose the protective layer;

and etching the exposed protective layer, and etching the glass substrate by taking the etched protective layer as a mask to form a plurality of columnar protruding structures.

10. The pyroelectric sensor is characterized by comprising the following components in sequence:

a substrate;

the chip support structure of any one of claims 1-7; and

a heat sensitive element; the heat sensitive element is arranged on one side of the chip supporting structure, which is provided with the columnar protruding structure.

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