CN207836769U - A kind of MEMS euthermic chips of integrated Pt temperature sensors - Google Patents

Abstract

The utility model discloses a MEMS electronic cigarette heating chip integrated with a Pt film resistance temperature sensor, comprising: a first substrate (1‑1), which is in the form of a sheet, and has a concave microcavity (2) on the front; the microcavity The body (2) has a micro-through hole (3) that runs through the first substrate (1-1); the second substrate (1-2) is in the form of a sheet, and its back has a micro-channel array perpendicular to its back (4), the front central area is provided with a porous structure (5) perpendicular to its front, and the microfluidic channel array (4) communicates with the porous structure (5); there are metal lead pads (6) on its front edge; its front surface There is a Pt thin film resistance temperature sensor (7); the front side of the first substrate (1‑1) is glued together with the back side of the second substrate (1‑2). The temperature of the electronic cigarette heating chip of the utility model can be measured in real time.

Description

A MEMS heating chip with integrated Pt temperature sensor

technical field

The utility model relates to the technical field of electronic cigarettes, in particular to a MEMS electronic cigarette heating chip integrated with a Pt film resistance temperature sensor.

Background technique

Most commercially available e-cigarettes use a heating wire as a heating element. In the power supply state, the heating wire heats the e-liquid through the high heat generated by electrothermal conversion to atomize it. Due to the spiral structure of the heating wire itself and the way the oil guide is wound on it, it is inevitable that the heating wire will experience local high temperature during operation. E-liquid components and oil-conducting materials will change in physical and chemical properties when the temperature of the e-cigarette is too high, and harmful cracking products may be produced; at high temperatures, some aroma components in the e-liquid will be destroyed, affecting the richness of the flavor; Excessively high smoke temperature will also cause excessively high temperature of the smoke generated by atomization, which may cause damage to the respiratory tract; in the case of insufficient supply of liquid smoke, the excessively high temperature will also burn the atomizing core (fuzzy core), resulting in paste. smell, and the vaping experience becomes worse.

In order to improve the above defects, in recent years, temperature control technology has appeared in electronic cigarettes. The basic principle of this temperature control technology is: the electronic cigarette temperature control chip monitors the temperature of the heating wire by reading the resistance of the heating wire. The heating wire is essentially a resistance wire. When the temperature of the heating wire rises, the number of collisions between metal ions inside the heating wire increases, and the resistivity of the metal changes with temperature. The temperature and resistance are related by the temperature coefficient of resistance. couplet. Specifically, the electronic cigarette has a built-in heating wire resistance detection circuit, which allows users to set the maximum temperature of the heating wire according to their own preferences. The reference resistance of the heating wire is measured at room temperature in order to determine the correct temperature related to the reference resistance value, and then, the operating temperature of the electronic cigarette is estimated by continuously measuring the resistance value when the electronic cigarette is started and applying the resistance-temperature formula. Through the specific algorithm of the temperature control chip, the output power of the battery is adjusted so that the resistance of the heating wire does not exceed the calculated value corresponding to the temperature set by the user. At present, the commonly used temperature control heating wire types mainly include nickel 200, titanium and 316 stainless steel wire. The advantage of this technology is that the heating wire will not be overheated or dry-burned, and it also avoids the odor and harmful substances produced by the high evaporation temperature of the e-liquid, which greatly improves the overall experience and safety of e-cigarettes.

At present, the "temperature control" applied to electronic cigarettes is actually based on the change of the resistance value of the metal to convert the corresponding temperature to realize the so-called "temperature control", which is finally realized based on the resistance change of the heating wire. This temperature control method does not use a temperature sensor to detect the temperature, but calculates the temperature information through the electronic cigarette host chip to calculate the change of the resistance of the heating wire. Therefore, in fact, the current temperature control of the electronic cigarette is based on the change of the resistance of the heating wire The basis is not judged by the actual temperature. As a result, the accuracy of the temperature is directly related to the accuracy of the resistance value. If the initial resistance value detected by the chip is not accurate, the temperature calculated according to the temperature coefficient of resistance will not be Exactly, if the base is wrong, the whole calculation is wrong. In addition, this temperature control method still has the following problems: the resistance value of the heating wire can only reflect the overall temperature situation, and when the local temperature is too high, it cannot be effectively monitored; secondly, during use, the heating wire will be aging due to high temperature, Oxidation and other reasons lead to changes in resistance, which will lead to larger and larger temperature measurement errors.

Among the many temperature measurement methods, the resistance temperature sensor (or resistance temperature detector, usually referred to as RTD) is one of the most accurate methods, and the advantage of the thin film resistance temperature sensor compared with the traditional RTD is high sensitivity and fast thermal response, which is Because of its smaller size reduces heat exchange between sensitive components and the environment. Platinum (Pt) metal is the material of choice for thin-film resistive temperature sensors due to its good response to heat, highly linear positive correlation between resistivity and temperature, and long-term chemical stability at high temperatures. At present, most Pt thin-film resistance temperature sensors can be prepared on silicon or metal substrates by CMOS (complementary metal oxide semiconductor) technology or MEMS (micro-electromechanical system) technology. The use of Pt in MEMS devices in particular allows the fabrication of structures that are highly resistant to plastic deformation at elevated temperatures.

Utility model content

The purpose of the utility model is to solve the problems existing in the existing electronic cigarette temperature control technology, and adopt advanced MEMS processing technology to design a MEMS electronic cigarette heating chip with an integrated temperature sensor and a manufacturing method thereof. Through the integrated Pt temperature sensor, the temperature of the MEMS heating chip can be accurately measured in real time, and with the external temperature controller, the accurate control of the MEMS heating chip can be realized, and the smoke liquid can be evenly atomized.

The first aspect of the utility model discloses a MEMS electronic cigarette heating chip integrated with a Pt thin film resistance temperature sensor, including:

The first substrate 1-1 is in the form of a sheet, and has a concave microcavity 2 on the front; the microcavity 2 has a micro through hole 3 that runs through the first substrate 1-1;

The second substrate 1-2 is in the shape of a sheet, and its back has a microfluidic channel array 4 perpendicular to its back, and the central area of the front is provided with a porous structure 5 perpendicular to its front, and the microfluidic channel array 4 is connected to the porous structure. 5 connected; there is a metal lead pad 6 on the front edge; there is a Pt thin film resistance temperature sensor 7 at the center of the front surface;

The front side of the first substrate 1-1 is bonded to the back side of the second substrate 1-2.

Preferably, the depth of the microcavity 2 is 1 mm to 5 mm; the diameter of the micro through hole 3 is 500 microns to 1 mm.

Preferably, there is a metal film on the front side of the second substrate 1-2, and the thickness of the metal film is 200-500nm; the material of the metal film is Ti/Pt/Au, TiW/Au, Al, Cr or One or more of Pt/Au.

Preferably, the diameter of the micro-channels of the micro-channel array 4 is 10 microns to 500 microns, and the depth of the micro-channels is 1/2˜3/4 of the height of the second substrate 1-2.

Preferably, the pore diameter of the porous structure 5 is 100 nm to 1000 nm.

Preferably, the first substrate is made of glass or high-resistance single-crystal silicon, and the resistivity of the high-resistance single-crystal silicon is greater than 10Ω·cm.

Preferably, the second substrate is made of low-resistance single-crystal silicon, and the resistivity of the low-resistance single-crystal silicon is less than 0.01Ω·cm.

The second aspect of the utility model discloses a method for preparing a MEMS electronic cigarette heating chip integrated with a Pt thin film resistance temperature sensor, including the following steps:

Preparation of the first substrate 1-1:

(1) Photolithographically form a microcavity pattern on the front surface of a glass sheet or a high-resistance single crystal silicon wafer with a resistivity greater than 10Ω·cm, and then use an etching solution to etch the microcavity 2;

(2) Photoetching the back of the glass sheet or high-resistance monocrystalline silicon wafer in step (1), and then using an etching solution to etch out the micro-through hole 3 that runs through the glass sheet or high-resistance monocrystalline silicon wafer; that is, obtain The first substrate 1-1;

Preparation of the second substrate 1-2:

(a) photoetching the back of a silicon wafer with a low resistivity of less than 0.01Ω·cm to form a microchannel array pattern;

(b) Etching the back side of the low-resistivity silicon wafer in step (a) by using a deep reactive ion etching process to form a microchannel array 4;

(c) using a low-pressure chemical vapor deposition process to deposit a layer of silicon nitride on the front side of the low-resistivity silicon wafer described in step (b);

(d) photolithography is carried out to the front side of the low-resistivity silicon wafer described in step (c), and the exposed silicon nitride layer in the middle is removed by a reactive ion etching process;

(e) using an electrochemical etching process to corrode the porous structure 5 on the front side of the low-resistivity silicon wafer obtained in step (d), so that the porous structure communicates with the microchannel array on the back;

(f) For the low-resistivity silicon wafer obtained in step (e), photolithography is carried out on the front side of the silicon wafer, and the Pt metal thin film is sputtered, and a Pt thin film resistance temperature sensor 7 is made by a stripping process;

(g) Reactive ion etching is used to remove the remaining silicon nitride on the front side of the low-resistivity silicon wafer described in step (e), and then the metal film is sputtered, and the metal pad 6 is made by a lift-off process, which is the first Two substrates 1-2;

Preparation of MEMS electronic cigarette heating chip integrated with Pt thin film resistance temperature sensor:

(A) The front side of the first substrate 1-1 is in close contact with the back side of the second substrate 1-2, and bonded together by bonding process;

(B) Using a dicing machine to scribe the chip obtained in step (A) to obtain the MEMS electronic cigarette chip with uniform heating.

Preferably, the etching solution described in step (1) or (2), wherein the etching solution for the glass sheet is hydrofluoric acid solution, and the etching solution for the high-resistance single crystal silicon wafer is potassium hydroxide solution or tetramethylammonium hydroxide One of the solutions.

Preferably, the material of the metal thin film sputtered in step (g) is one or more of Ti/Pt/Au, TiW/Au, Al, Cr or Pt/Au.

Beneficial results of the utility model:

(1) The utility model uses an integrated platinum resistance temperature sensor to measure the temperature of the heating chip of the electronic cigarette in real time. The temperature measurement is accurate, the sensor has a long service life, and the work is reliable, which effectively avoids the inaccurate temperature measurement of the heating element of the existing electronic cigarette. Aging leads to problems such as constant changes in temperature measuring resistance; at the same time, the temperature can be adjusted according to user needs, thereby changing the amount of atomization.

(2) The manufacturing process of the MEMS electronic cigarette heating chip integrated with the Pt thin film resistance temperature sensor of the utility model is simple, the process standard is suitable for mass production.

Description of drawings

Fig. 1 is a side sectional view of a MEMS electronic cigarette heating chip integrating a Pt thin film resistance temperature sensor of the present invention;

Fig. 2 is a side sectional view of the first substrate of the present invention;

Fig. 3 side sectional view of the second substrate;

Fig. 4 the front top view of the second substrate;

Fig. 5 is a top view of the back of the second substrate.

Reference numerals are: 1-1, first substrate; 2, microcavity; 3, micro through hole; 4, micro flow channel display; 5, porous structure; 6, metal pad; 7, Pt temperature sensor; 8. Silicon nitride layer

Detailed ways

A MEMS electronic cigarette heating chip integrated with a Pt thin film resistance temperature sensor of the utility model comprises:

The first substrate 1-1 is disc-shaped, and has a concave microcavity 2 on its front; the microcavity 2 has a micro through hole 3 that runs through the first substrate 1-1;

The second substrate 1-2 is in the shape of a disc, and its back has a microfluidic array 4 perpendicular to its back, and the central area of the front is provided with a porous structure 5 perpendicular to its front, and the microfluidic array 4 is connected to the porous The structure 5 is connected; the front edge has a metal lead pad 6; the center of the front surface has a Pt thin film resistance temperature sensor 7;

The front side of the first substrate 1-1 is bonded to the back side of the second substrate 1-2.

The depth of the microcavity 2 is selected as 3 mm; the diameter of the micro through hole 3 is selected as 750 microns.

There is a metal film on the front side of the second substrate 1-2, the thickness of the metal film is selected as 300nm; the material of the metal film is selected as Ti/Pt/Au.

The diameter of the micro-channels of the micro-channel array 4 is selected as 30 microns, and the depth of the micro-channels is selected as 1/2 of the height of the second substrate 1-2.

The pore diameter of the porous structure 5 is selected as 500 nanometers.

The first substrate is selected to be made of high-resistance single-crystal silicon, and the resistivity of the high-resistance single-crystal silicon is selected to be 20Ω·cm.

The second substrate is made of low-resistance single-crystal silicon, and the resistivity of the low-resistance single-crystal silicon is selected as 0.005Ω·cm.

The second aspect of the utility model discloses a method for preparing a MEMS electronic cigarette heating chip integrated with a Pt thin film resistance temperature sensor, including the following steps:

Preparation of the first substrate 1-1:

(1) Forming microcavity patterns by photolithography on the front side of a high-resistance monocrystalline silicon wafer with a resistivity of 20 Ω cm, and then using an etching solution potassium hydroxide solution to etch out the microcavity 2;

(2) Photoetching the back of the high-resistance single-crystal silicon wafer in step (1), and then using an etching solution as a potassium hydroxide solution to etch out micro-vias 3 that run through the high-resistance single-crystal silicon wafer; The first substrate 1-1 described above;

Preparation of the second substrate 1-2:

(a) photoetching the back of the silicon wafer with a low resistivity of 0.005Ω·cm to form a microchannel array pattern;

(b) Etching the back side of the low-resistivity silicon wafer in step (a) by using a deep reactive ion etching process to form a microchannel array 4;

(c) using a low-pressure chemical vapor deposition process to deposit a layer of silicon nitride on the front side of the low-resistivity silicon wafer described in step (b);

(d) photolithography is carried out to the front side of the low-resistivity silicon wafer described in step (c), and the exposed silicon nitride layer in the middle is removed by a reactive ion etching process;

(e) using an electrochemical etching process to corrode a porous structure (5) on the front side of the low-resistivity silicon wafer obtained in step (d), so that the porous structure communicates with the microchannel array on the back;

(f) For the low-resistivity silicon wafer obtained in step (e), photolithography is carried out on the front side of the silicon wafer, and the Pt metal thin film is sputtered, and a Pt thin film resistance temperature sensor 7 is made by a stripping process;

(g) Reactive ion etching is used to remove the remaining silicon nitride on the front side of the low-resistivity silicon wafer described in step (e), and then the sputtered metal film material is Ti/Pt/Au, and the stripping process is used to make metal solder disc 6, which is the second substrate 1-2;

Preparation of MEMS electronic cigarette heating chip integrated with Pt thin film resistance temperature sensor:

(A) The front side of the first substrate (1-1) is in close contact with the back side of the second substrate 1-2, and bonded together by bonding process;

(B) Using a dicing machine to scribe the chip obtained in step (A) to obtain the MEMS electronic cigarette chip with uniform heating.

Claims (7)

1. a kind of MEMS electronic cigarette euthermic chips of integrated Pt film resistor temperature sensors, which is characterized in that including：

First substrate (1-1), in the form of sheets, front have the microcavity body (2) of concave；Have in the microcavity body (2) through described the The micro through hole (3) of one substrate (1-1)；

Second substrate (1-2), in the form of sheets, the back side have the miniflow channel array (4) perpendicular to its back side, and front center region is equipped with Perpendicular to its positive porous structure (5), the miniflow channel array (4) is connected to porous structure (5)；Its front edge has metal Lead pad (6)；There are one Pt film resistor temperature sensors (7) for its front face surface；

The front of first substrate (1-1) is together with the back adhesive of second substrate (1-2).

2. the MEMS electronic cigarette euthermic chips of integrated Pt film resistor temperature sensors according to claim 1, feature It is, the depth of the microcavity body (2) is 1 millimeter to 5 millimeters；A diameter of 500 microns to 1 millimeter of the micro through hole (3).

3. the MEMS electronic cigarette euthermic chips of integrated Pt film resistor temperature sensors according to claim 1, feature It is, there is metallic film in the front of second substrate (1-2), and the thickness of the metallic film is 200~500nm；The gold The material for belonging to film is one or more of Ti/Pt/Au, TiW/Au, Al, Cr or Pt/Au.

4. the MEMS electronic cigarette euthermic chips of integrated Pt film resistor temperature sensors according to claim 1, feature It is, a diameter of 10 microns to 500 microns of the fluid channel of the miniflow channel array (4), the depth of the fluid channel is described The 1/2~3/4 of second substrate (1-2) height.

5. the MEMS electronic cigarette euthermic chips of integrated Pt film resistor temperature sensors according to claim 1, feature It is, the aperture of the porous structure (5) is 100 nanometers to 1000 nanometers.

6. the MEMS electronic cigarette euthermic chips of integrated Pt film resistor temperature sensors according to claim 1, feature It is, first substrate is made of glass or high resistant monocrystalline silicon, and the resistivity of the high resistant monocrystalline silicon is more than 10 Ω cm.

7. the MEMS electronic cigarette euthermic chips of integrated Pt film resistor temperature sensors according to claim 1, feature It is, second substrate is made of low-resistance single crystal silicon, and the resistivity of the low-resistance single crystal silicon is less than 0.01 Ω cm.