CN223346291U - Negative temperature coefficient thermistor temperature sensor and monocrystalline silicon substrate for preparing same - Google Patents

Abstract

The utility model discloses a negative temperature coefficient thermistor temperature sensor and a monocrystalline silicon substrate for preparing the same, belonging to the detection field, the thermistor temperature sensor comprises a monocrystalline silicon substrate block and a negative temperature coefficient thermosensitive film which is grown on a silicon dioxide layer of the monocrystalline silicon substrate block, wherein the negative temperature coefficient thermosensitive film is a Mn-Co-Ni-Cu-O thermosensitive film and has a spinel structure. According to the utility model, through pre-cutting with 1/3 thickness on the monocrystalline silicon substrate, in-plane residual stress of the thermosensitive film can be reduced in the preparation process, the Mn-Co-Ni-Cu-O thermosensitive film with the thickness of more than 7.7 mu m is prepared, the surface of the thermosensitive film is good and is well combined with a silicon dioxide layer, cracking and falling do not occur, the resistance is less than 500 omega, annealing heat treatment is not needed, and compared with the prior art, the monocrystalline silicon substrate can enable the production of the thermosensitive film to be simple and efficient, and the production efficiency and yield are very high.

Description

Negative temperature coefficient thermistor temperature sensor and monocrystalline silicon substrate for preparing same

Technical Field

The utility model relates to the field of detection, in particular to a negative temperature coefficient thermistor temperature sensor and a monocrystalline silicon substrate for preparing the same.

Background

The Negative Temperature Coefficient (NTC) thermistor temperature sensor has the advantages of high temperature measurement precision, high sensitivity, good stability, low price, long service life and the like, and has wide and important application in the fields of aerospace, marine environment, household appliances and the like. However, as integrated circuit process is smaller and smaller, wafer multiparameter, multi-module integration is higher and higher, requiring NTC thermistors with smaller dimensions, higher measurement accuracy, and less uncertainty.

At present, a plurality of block, flake and sphere thermistor temperature sensors exist in the market, but the problems of large volume, complex manufacturing process, large product batch performance difference, further improvement of measurement precision and accuracy and the like exist, and the requirements of the fields of integrated circuits, advanced manufacturing, micro-nano processing and the like on smaller size, higher measurement precision and smaller measurement uncertainty of the temperature sensors cannot be met.

Compared with block, slice and sphere thermosensitive temperature sensors, the negative temperature coefficient thermosensitive film has the most possible application requirements of integrated circuits, advanced manufacturing and micro-nano devices. At present, some research groups successfully prepare the negative temperature coefficient thermosensitive film through a magnetron sputtering method, a molecular beam epitaxy method, a pump laser deposition method or a chemical solution deposition method and the like. The method for preparing the thermosensitive film by magnetron sputtering is a main existing method, and the technical route is that firstly, the thermosensitive film is prepared on a monocrystalline silicon wafer with a silicon dioxide layer by magnetron sputtering, the thickness of the prepared thermosensitive film is usually tens to hundreds of nanometers, and the thickness of the prepared thermosensitive film cannot exceed 1 mu m because the brittle thermosensitive film is prepared on a (4-8) inch monocrystalline silicon wafer by magnetron sputtering. If the thickness of the brittle thermosensitive film exceeds 1. Mu.m, the in-plane residual stress thereof is large, which may cause cracking or peeling of the film from the substrate.

However, if the thickness of the thermosensitive film is too small (several tens to several hundreds nanometers), the resistance is very large, usually (100 to 1000) kΩ, and the resistance is too large, so that the temperature measurement accuracy and resolution of the thermosensitive film are poor. Therefore, in order to reduce the thermistor, the prepared thermosensitive film must be subjected to multiple annealing heat treatments, which can reduce the thermistor and release the residual stress in the surface of the thermosensitive film. After annealing heat treatment, an electrode is prepared on the surface of the thermosensitive film by using an evaporation coating or other technologies. After the electrode is prepared, a laser cutting machine is used for cutting the wafer in full thickness, and a separated single thermosensitive device is obtained. Because a large number of heat sensitive devices are arranged on a large wafer, the large wafer can be practically used after being cut and separated.

The existing technical route for preparing the thermosensitive film by magnetron sputtering has the problems that 1) the prepared thermosensitive film needs to be subjected to annealing heat treatment for multiple times to reduce resistance and in-plane residual stress, the technical route is long and operation is complex, 2) the thermosensitive film is easy to oxidize in the process of annealing heat treatment for multiple times to change the chemical composition of the thermosensitive film, 3) the electrode is prepared by using evaporation coating or other technologies, the complexity and operability of the technical route are increased, the electrode prepared by the technologies is easy to break and lose efficacy, and 4) finally, the thermosensitive device on a wafer is cut and separated, so that the thermosensitive device is easy to pollute and damage, and the yield is reduced. These problems have prevented the development and application of negative temperature coefficient thermosensitive film temperature sensors in the fields of integrated circuits and the like.

Disclosure of utility model

Object of the utility model

In order to overcome the defects, the utility model aims to provide a simple and efficient negative temperature coefficient thermistor temperature sensor with high production efficiency and yield and a monocrystalline silicon substrate for preparing the same.

Solution scheme

In order to achieve the purpose of the utility model, the technical scheme adopted by the utility model is as follows:

In a first aspect, the present utility model provides a negative temperature coefficient thermistor temperature sensor comprising a monocrystalline silicon substrate block and a negative temperature coefficient thermosensitive film grown on a silicon dioxide layer of the monocrystalline silicon substrate block, wherein the negative temperature coefficient thermosensitive film is a Mn-Co-Ni-Cu-O thermosensitive film, and has a spinel structure.

Further, the negative temperature coefficient thermosensitive film has a thickness of 7.5 μm or more, alternatively 7.7 μm or more.

Further, the negative temperature coefficient thermosensitive film has a resistance of less than 500 Ω.

Further, the size of the negative temperature coefficient thermosensitive film is (2-10) mm× (2-10) mm, optionally 5mm×5mm.

Further, the negative temperature coefficient thermosensitive film is formed by adopting an Mn-Co-Ni-Cu-O alloy target material to deposit for a plurality of times through a physical deposition coating method, wherein the physical deposition coating method comprises a magnetron sputtering method, a laser molecular beam epitaxy method or an electron beam evaporation method, and the deposition times are at least twice.

Further, in the negative temperature coefficient thermosensitive film, the mass ratio of Mn, co, ni, cu, O can be 30:30:15.5:0.5:24, and can be adjusted according to the requirement.

Further, the spinel structure unit cell has a structure of AB ₂O₄ in which a ions occupy oxygen tetrahedral voids composed of four oxygen atoms and B ions occupy oxygen octahedral voids composed of six oxygen atoms.

In a second aspect, there is provided a monocrystalline silicon substrate for preparing the negative temperature coefficient thermistor temperature sensor according to the first aspect, wherein grooves which are longitudinally and transversely interwoven are cut on the monocrystalline silicon substrate, and a plurality of small units are formed and used for being divided into a plurality of monocrystalline silicon substrate blocks along the grooves.

Further, the depth of the groove on the monocrystalline silicon substrate is 160-320 mu m, alternatively, the depth of the groove is 1/4-1/2 of the thickness of the monocrystalline silicon substrate, alternatively, 1/3;

further, the small units are square units, and the size of the square units is (2-10) mm, and 5mm×5mm.

Advantageous effects

According to the utility model, through pre-cutting with 1/3 thickness on the monocrystalline silicon substrate, in-plane residual stress of the thermosensitive film can be reduced in the preparation process, the Mn-Co-Ni-Cu-O thermosensitive film with the thickness of more than 7.7 mu m is prepared, the surface of the thermosensitive film is good and is well combined with a silicon dioxide layer, cracking and falling do not occur, the prepared thermosensitive film resistor is less than 500 omega, annealing heat treatment is not needed, and compared with the prior art, the monocrystalline silicon substrate can enable the production of the thermosensitive film to be simple and efficient, and the production efficiency and the yield are very high.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings. The word "exemplary" is used herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

FIG. 1 is a view of a single crystal silicon substrate of the present utility model pre-cut to 1/3 thickness.

FIG. 2 is a top view block diagram of one embodiment of a monocrystalline silicon substrate of a fabricated negative temperature coefficient thermistor temperature sensor of the present utility model.

FIG. 3 is a partial structure of an interface diagram of a monocrystalline silicon substrate of a fabricated NTC thermistor temperature sensor according to the present utility model.

FIG. 4 is an SEM image of a Mn-Co-Ni-Cu-O thermosensitive film prepared in example 1 of the present utility model.

FIG. 5 is an AFM image of a Mn-Co-Ni-Cu-O thermosensitive film prepared in example 1 of the present utility model.

FIG. 6 is a TEM image of a Mn-Co-Ni-Cu-O thermosensitive film prepared in example 1 of the present utility model.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions in the embodiments of the present utility model will be clearly and completely described below, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In addition, numerous specific details are set forth in the following description in order to provide a better illustration of the utility model. It will be understood by those skilled in the art that the present utility model may be practiced without some of these specific details. In some embodiments, materials, elements, methods, means, etc. well known to those skilled in the art are not described in detail in order to highlight the gist of the present utility model.

Throughout the specification and claims, unless explicitly stated otherwise, the term "comprise" or variations thereof such as "comprises" or "comprising", etc. will be understood to include the stated element or component without excluding other elements or components.

The utility model provides a negative temperature coefficient thermistor temperature sensor, as shown in figure 1, which comprises a monocrystalline silicon substrate block 1 'and a negative temperature coefficient thermosensitive film 3 grown on a silicon dioxide layer 10 of the monocrystalline silicon substrate block 1', wherein the negative temperature coefficient thermosensitive film 3 is a Mn-Co-Ni-Cu-O thermosensitive film and has a spinel structure.

The single crystal silicon substrate block 1' refers to a small block formed by dividing the single crystal silicon substrate block. When in use, 80 mu m diameter platinum wire is adhered on two sides of the negative temperature coefficient thermosensitive film by using silver colloid to form an electrode.

The thickness of the thermosensitive film of the present utility model can exceed 7.7 μm. And the thermosensitive film resistor is less than 500 omega.

Further, the size of the negative temperature coefficient thermosensitive film 3 is (2 to 10) mm× (2 to 10) mm, optionally 5mm×5mm.

Further, the negative temperature coefficient thermosensitive film 3 is formed by adopting an Mn-Co-Ni-Cu-O alloy target material to deposit for a plurality of times through a physical deposition coating method, wherein the physical deposition coating method comprises a magnetron sputtering method, a laser molecular beam epitaxy method or an electron beam evaporation method, and the deposition times are at least twice. The thickness of the thermosensitive film can be increased by multiple depositions.

Further, in the negative temperature coefficient thermosensitive film 3, the mass ratio of Mn, co, ni, cu, O can be 30:30:15.5:0.5:24, and can be adjusted according to the requirement.

Further, the spinel structure unit cell has a structure of AB ₂O₄ in which a ions occupy oxygen tetrahedral voids composed of four oxygen atoms and B ions occupy oxygen octahedral voids composed of six oxygen atoms.

In a second aspect, a monocrystalline silicon substrate 1 (see fig. 2 and 3) for preparing the negative temperature coefficient thermistor temperature sensor according to the first aspect is provided, grooves 2 are cut on the monocrystalline silicon substrate 1, and a plurality of small units (one small unit corresponds to one monocrystalline silicon substrate block 1 ') are formed by longitudinally and transversely interweaving the grooves 2, and are used for dividing the grooves 2 into a plurality of monocrystalline silicon substrate blocks 1'.

The single crystal silicon substrate 1/3 thickness pre-cut can reduce in-plane residual stress of the thermosensitive film, avoid cracking and falling of the film, optimize the technical route of preparing the thermosensitive film by magnetron sputtering, and improve production efficiency and yield.

Further, the depth of the groove 2 on the monocrystalline silicon substrate 1 is 160-320 μm, and optionally, the depth of the groove 2 is 1/4-1/2 of the thickness of the monocrystalline silicon substrate 1, and optionally, 1/3.

Further, the small units are square units, and the size of the square units is (2-10) mm, and 5mm×5mm.

One specific preparation method of the negative temperature coefficient thermistor temperature sensor of the utility model can be as follows:

1) Pre-treating a Mn-Co-Ni-Cu-O alloy target, namely preparing the Mn-Co-Ni-Cu-O alloy target by Mn, co, ni, cu and O elements according to the mass fraction ratio of 30:30:15.5:0.5:24, sequentially polishing the surface of the Mn-Co-Ni-Cu-O alloy target by using 300-mesh, 600-mesh, 1200-mesh and 1800-mesh silicon carbide sand paper, cleaning and drying after polishing, and removing a surface oxide layer to obtain the pretreated Mn-Co-Ni-Cu-O alloy target;

2) Cutting the monocrystalline silicon substrate 1/3, namely cutting the monocrystalline silicon substrate with the silicon dioxide layer 1/3 by using a silicon wafer laser cutting machine, carrying out longitudinal and transverse cutting on the surface of the silicon dioxide layer, interweaving transverse grooves and longitudinal grooves on the monocrystalline silicon substrate to form a plurality of square small blocks with the thickness of 5mm multiplied by 5mm, wherein the whole monocrystalline silicon substrate is still a complete monocrystalline silicon wafer, see fig. 2 and 3, and the 1/3 thickness precutting of the monocrystalline silicon substrate in the step can optimize the technical route of preparing the thermosensitive film by magnetron sputtering and improve the production efficiency and the yield.

3) Pre-treating a monocrystalline silicon substrate, namely immersing the cut monocrystalline silicon substrate in acetone, absolute ethyl alcohol, deionized water and absolute ethyl alcohol in sequence for ultrasonic washing for 2 times, wherein each washing time is 5 minutes, taking out the monocrystalline silicon substrate, and drying the surface of the monocrystalline silicon substrate by utilizing high-purity nitrogen to obtain the pre-treated monocrystalline silicon substrate;

4) Pre-sputtering the Mn-Co-Ni-Cu-O alloy target, namely mounting the Mn-Co-Ni-Cu-O alloy target subjected to pretreatment in the step 1) on a target position at the bottom of a cavity of a direct current magnetron sputtering instrument, mounting the monocrystalline silicon substrate subjected to pretreatment in the step 3) on a substrate table at the top of the cavity of the direct current magnetron sputtering instrument, closing a magnetron sputtering instrument cavity, starting a vacuum system to perform vacuum pumping, starting a molecular pump and closing the mechanical pump after the vacuum degree of the cavity is pumped to be less than 10 ^-2 Torr by a mechanical pump, setting Ar gas flow to be 50sccm after the vacuum degree of the cavity is pumped to be less than 10 ^-7 Torr, setting sputtering power of the alloy target to be 240W, and blocking the Mn-Co-Ni-Cu-O alloy target by a baffle plate extending above the target position to perform pre-sputtering for 30 minutes to remove pollutants and impurities on the surface of the alloy target;

5) The Mn-Co-Ni-Cu-O thermosensitive film is prepared by pre-sputtering an alloy target for 30min, withdrawing a baffle above the alloy target, starting to coat a film on monocrystalline silicon, keeping Ar gas flow at 50sccm, keeping power at 240W, turning off voltage and current after sputtering coating for 200min, cooling the whole magnetron sputtering system for 60min, then recovering the voltage and current, continuing sputtering coating for 300min, turning off the voltage and current after sputtering coating is finished, opening a cavity after cooling for 40min, and taking out the prepared Mn-Co-Ni-Cu-O thermosensitive film.

6) The Mn-Co-Ni-Cu-O thermosensitive film and the monocrystalline silicon substrate are broken along the grooves and divided into small blocks with the length of 5mm multiplied by 5mm (because of the longitudinal grooves and the transverse grooves on the monocrystalline silicon substrate, most sputtering materials enter the groove bottom during sputtering, and a small part of the sputtering materials are adhered between the small blocks with the length of 5mm multiplied by 5mm, namely, the small blocks with the length of 5mm multiplied by 5mm are connected with weak points and are easy to break off).

7) Then, liquid silver glue is dripped on two ends of each thermosensitive film small block, one end of a platinum wire with the length of 1.5cm and the diameter of 80 mu m is rapidly stretched into the silver glue solution drop by forceps, the silver glue is kept stable (20-30) s, after solidification, the forceps are loosened, 1-2 drops of silver glue are continuously dripped on the bonding end of the platinum wire, and the whole thermosensitive resistor device is placed at a ventilated drying position for drying (4-5) hours.

In the step 4), other physical deposition coating methods such as laser molecular beam epitaxy, electron beam evaporation and the like can be adopted to prepare the Mn-Co-Ni-Cu-O thermosensitive film.

The Mn-Co-Ni-Cu-O thermosensitive films prepared by the method are respectively shot by a scanning electron microscope (Scanning Electron Microscope, SEM), an atomic force microscope (Atomic Force Microscope, AFM) and a transmission electron microscope (Transmission Electron Microscope, TEM), the results are respectively shown in figures 4, 5 and 6, and the results show that the surfaces of the thermosensitive films are very flat, the roughness is (15-20) nm, the film thickness is 7.7 mu m, the thermosensitive films are formed by columnar crystals and densely grow, and the crystal structure is mainly a spinel structure.

And then detecting the resistance of the thermosensitive film of the thermosensitive resistor device by adopting an unbalanced bridge method to detect the resistance of each embodiment and the comparative example, simultaneously recording the output voltage of the unbalanced bridge and the resistance value of the thermosensitive resistor measured by the digital multimeter when the preset temperature is stable, and repeating the process at different temperatures to achieve enough measurement points. The resistance of the Mn-Co-Ni-Cu-O thermosensitive film prepared by the method is 420 omega.

The thickness of the thermosensitive film can exceed 7.7 mu m through multiple splashing, and the Mn-Co-Ni-Cu-O thermosensitive film grown by magnetron sputtering is formed into square small blocks with the area of 5mm multiplied by 5mm by pre-cutting 1/3 of the thickness on the monocrystalline silicon substrate, so that the residual stress generated in the growth process of the thermosensitive film can be reduced, the thermosensitive film is prevented from cracking and falling off, and the prepared thermosensitive film can be directly broken and segmented, so that the method is simple and efficient. Therefore, the thermosensitive film prepared by the utility model has good surface and good combination with the silicon dioxide layer on the monocrystalline silicon substrate, and does not crack or fall off. Compared with the prior art, the technical route is simple and efficient, and the production efficiency and the yield are very high.

The negative temperature coefficient thermosensitive film sensor comprises a platinum wire electrode, a Mn-Co-Ni-Cu-O thermosensitive film, insulating silicon dioxide and a monocrystalline substrate, wherein the Mn-Co-Ni-Cu-O thermosensitive film has a spinel structure which can be regarded as cubic close packing formed by oxygen ions, the unit cell structure is AB ₂O₄, wherein A ions occupy oxygen tetrahedral gaps formed by four oxygen atoms, B ions occupy oxygen octahedral gaps formed by six oxygen atoms, and the thermosensitive property of the spinel structure thermosensitive material is greatly dependent on jump conduction among variable valence cations in the oxygen octahedron in the crystal structure. The oxygen octahedral structure of the Mn-Co-Ni-Cu-O thermosensitive film can be separated to obtain oxygen vacancies with a certain concentration, and the oxygen vacancies can provide extra electrons, also cause deviation of stoichiometric ratio of materials, change of valence state of metal cations, oxygen octahedral distortion and the like, so that the physical properties of the materials are effectively improved and regulated, and the thermosensitive performance of the film is improved.

It should be noted that the above-mentioned embodiments are merely for illustrating the technical solution of the present utility model, and not for limiting the same, and although the present utility model has been described in detail with reference to the above-mentioned embodiments, it should be understood by those skilled in the art that the technical solution described in the above-mentioned embodiments may be modified or some technical features may be equivalently replaced, and these modifications or substitutions do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solution of the embodiments of the present utility model.

Claims (10)

1. A negative temperature coefficient thermistor temperature sensor, characterized in that it includes a single crystal silicon substrate block and a negative temperature coefficient thermistor film grown on a silicon dioxide layer of the single crystal silicon substrate block, wherein the negative temperature coefficient thermistor film is a Mn-Co-Ni-Cu-O thermistor film having a spinel structure. 2. The negative temperature coefficient thermistor temperature sensor according to claim 1, wherein the thickness of the negative temperature coefficient thermistor film is ≥7.5 μm; And/or, the resistance of the negative temperature coefficient thermistor film is less than 500Ω. 3 . The negative temperature coefficient thermistor temperature sensor according to claim 1 , wherein platinum wires are adhered to both sides of the negative temperature coefficient thermistor film. 4 . The negative temperature coefficient thermistor temperature sensor according to claim 1 , wherein the size of the negative temperature coefficient thermistor film is (2-10) mm×(2-10) mm. 5. The negative temperature coefficient thermistor temperature sensor according to any one of claims 1 to 4, characterized in that the negative temperature coefficient thermistor thin film is formed by multiple depositions using a Mn-Co-Ni-Cu-O alloy target by a physical deposition coating method. 6. The negative temperature coefficient thermistor temperature sensor according to any one of claims 1 to 4, characterized in that the negative temperature coefficient thermistor thin film is formed by depositing a Mn-Co-Ni-Cu-O alloy target twice by a physical deposition coating method. 7. A single crystal silicon substrate for preparing a negative temperature coefficient thermistor temperature sensor according to any one of claims 1 to 6, characterized in that the single crystal silicon substrate is cut with grooves interlaced vertically and horizontally to form a plurality of small units, which are used to be divided into a plurality of single crystal silicon substrate blocks along the grooves. 8 . The single crystal silicon substrate according to claim 7 , wherein the depth of the groove on the single crystal silicon substrate is 160 μm to 320 μm. 9 . The single crystal silicon substrate according to claim 7 , wherein the depth of the groove is 1/4 to 1/2 of the thickness of the single crystal silicon substrate. 10. The single crystal silicon substrate according to any one of claims 7 to 9, wherein the plurality of small units are a plurality of square units; And/or, the size of the small unit is (2-10) mm×(2-10) mm.