TW200531124A - Sensor integrating with temperature, humidity and pressure, and manufacturing method thereof - Google Patents

Abstract

The present invention provides a sensor integrating with temperature, humidity and pressure, and the manufacturing method thereof. A silicon substrate is connected with a bottom plate, and the substrate is utilized to produce three sensing devices, that is, temperature, humidity and pressure sensors by a process of micro electromechanical system (MEMS). The temperature sensor employs a thermal-sensitive resistor to generate resistance variation due to a change of temperature to sense the temperature, or by the generating voltage from a thermal couple due to temperature variation. A separation space is established between the temperature sensor and the bottom plate for reducing thermal, and decreasing the heat conduction of the temperature sensor. The humidity sensor employs a polymer material to absorb the water, so that causes the dielectric change of the polymer material, and further employs the capacitance variation to measure the humidity. The pressure sensor employs the deformation of a thin film due to pressure change, and the voltage resistance on the thin film will be varied to sense the pressure. The temperature, humidity and pressure sensors could be fabricated in a continuous and integrated process, and this process could be associated with CMOS process, that is, the signal processing circuit will be fabricated by employing the CMOS process, and then the sensor will be directly produced on the signal processing circuit.

Description

200531124 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to an improvement in the structure and manufacturing method of a micro-sensor, particularly a sensor that integrates temperature, humidity, and pressure, and a method for manufacturing the same. Previous technology] With the development of science and technology, the research and development and breakthroughs of semiconductor technology have enabled an item to be miniaturized. For example, the original computer must have a processor that is large enough to occupy a large room. The transistors are composed one by one, and today's computer microprocessors only need an area of the size of a tea bag, and the operation speed is hundreds of thousands of times. The smallest unit of measurement has evolved from micrometers (μin) to nanometers. (Nm) or sub-nanometer (0.1 nm). Similarly, in many industries, it is gradually miniaturized, such as nano-coatings, bio-chemical products developed by nano-technology, etc .; similarly, the semiconductor manufacturing process Thanks to the emergence of Micro-ElectroMechanical System (MEMS) technology, as the name implies, it means that electromechanical components can be miniaturized, such as micromotors, micro Pumps or micro-sensors, etc., many scholars, experts and industries have invested a lot of money in research and development of related products, so you can often see relevant information in some journals, such as MEMS Journal (J urna 1 〇 f

MicroElectromechanical Systems) or journals published by the Institute of Electronic and Electrical Engineers (I EEE). In terms of existing information, most microsensors are mostly microsensors with a single function. Measure temperature or humidity, such as Mehment D 〇kmeei and K ha 1 i 1 N ajafi in the paper published in MEMS Journal in 2001, using MEMS manufacturing system

Page 5 Sex has always been tested in one device. Multiple and physical integration into one whole, less questions about the freshness of the sense of the way to the tester > technical and electrical multiple questions now to ask the current location of the operation decision system technical solution can be included as soon as possible Nakanetaka released and Cheng Ming wanted to combine the hair and make the hairpin, together [(Integral 200531124 V. Description of the invention (2) as a hygrometer, and in 2002, Celine Lavill e and C 1 aude P e 1 1 et also uses a micro-electro-mechanical process to make a medical humidity sensor. Rarely can it be found that integrating multiple sensors in one and contains a signal processing circuit. The applicant has carefully studied this to integrate multiple physical quantity sensors. "Technical means to solve the problem" The present invention uses a silicon-based substrate to connect a bottom plate, and uses the micro-electro-mechanical process to make three sensing elements, that is, temperature, humidity, and pressure sensors. The temperature sensing The device senses temperature by using a thermistor to generate resistance changes due to temperature changes, and a space is provided between the temperature sensor and the bottom plate. The space is mainly to prevent the temperature sensor from sensing the temperature. Temperature easily from temperature In the tester, the measured temperature is not accurate due to the decrease in heat conduction. The humidity sensor uses a polymer material to absorb water, which causes the dielectric value of the polymer material to change, and then uses the capacitance value. The humidity is changed to measure the humidity. The present invention is a capacitive humidity sensor. A polymer material is further spaced between the two electrodes. When the property of the polymer material is to absorb moisture, it will change.

Page 6 200531124 V. Description of the invention (3) Change the dielectric value, and set one electrode above and below the polymer material, and two electrodes like fences on the upper electrode, and then cooperate with the lower electrode to form The two capacitors are connected in series, and the upper electrode is designed in a grid shape, which mainly allows the polymer material to have more area to contact the outside environment, so as to increase the response speed of the humidity sensor.

The pressure sensor uses a piezoresistive change to sense the pressure. First, the pressure sensor is on a silicon substrate, and the doped portion is made into a semiconductor by ion doping. The semiconductor can be regarded as a pressure. Resistance, also uses the resistance change of the semiconductor to sense the pressure change, and a space is provided on the bottom surface of the pressure sensor, and then the space is sealed by the bottom plate, so that the pressure sensor has a reference pressure, and At this time, the piezoresistance has become a thin film. One side of the thin film piezoresistance is the reference pressure, and the other side is the external pressure. Therefore, when the external pressure is less than the reference pressure, the thin film piezoresistance will bulge outward. The film changes its resistance due to the pressure difference, so as to measure the pressure. The temperature, humidity, and pressure sensors can be completed in a consistent integrated process, and the process can be matched with the CMOS process, that is, the signal processing circuit is first produced by the CMOS process, and then directly produced by the signal processing circuit. Sensor.

"Effects on the previous technology" After the improvement of this creation, its advantages can be summarized as follows: 1. The present invention can use the consistent integration process to make three types of sensors, saving a lot of process time, cost and improving yield.

Page 7 200531124 V. Description of the invention (4) 2. The process of the present invention is compatible with the CMOS process, so the sensor can be directly manufactured after the signal processing circuit is completed to reduce the process and cost. 3. Because the present invention uses micro-electromechanical technology to make the sensor, its volume is quite small, the space occupied by it is very small, and the energy consumed is also relatively small. It can be used in general homes, companies and hospitals. The system can control the pressure, temperature and humidity in the room, and cooperate with the automatic control of the air-conditioning system, so that the environment can be adjusted to an environment with a small temperature gradient and appropriate pressure and humidity. 4. The invention can also be applied to medical treatment, because its volume is quite small, it can be directly made into a device, which can be directly used in the human body to measure blood pressure, pulse and temperature, and it can immediately directly monitor some changes in the human body to promptly remind The user pays attention to the physical condition, so the application of the invention is quite extensive. [Embodiment] The following description of the embodiment of the present invention will be made clear with reference to the drawings. A sensor integrating temperature, humidity and pressure, comprising: a silicon substrate 4 connected to a base plate 5 (such as glass), and using the micro-electro-mechanical process to produce three sensing elements on the substrate, namely temperature, humidity and pressure Sensors, and the present invention can use the consistent integration process to make three types of sensors, saving many process times, costs, and improving yield. Please refer to the first diagram and the second diagram, which are a structural diagram of the present invention and a combined diagram of a sensor and a signal processing circuit.

200531124 V. Description of Invention (5)

The temperature sensor 1 senses temperature by using a thermistor 11 to generate resistance changes due to temperature changes. As we know, general metals have the characteristics of thermal expansion and contraction. Therefore, as long as you understand the physical characteristics of the metal, Combined with a signal processing circuit a, it can be used as a sensor. For example, we use the characteristics of the metal's thermal expansion and contraction to affect the resistance of the metal to measure the temperature. However, different metals have different thermal expansion coefficients. Generally, metals with larger thermal expansion coefficients are used. When the metal's thermal expansion coefficient is large, the volume change of metal to temperature is more obvious. When the volume of metal changes, its resistance changes accordingly. In the example, nickel is used as the thermistor 11 of the temperature sensor 1. The recording resistance value is higher than that of general metals, and its sensitivity to heat is greater. The change in temperature changes its resistance value more than ordinary metals, and its price is cheap, and When the temperature sensor 1 senses temperature, the temperature sensor 1 should only consume a small amount of heat, and it must prevent the thermal conductivity of the temperature sensor 1 from affecting the measured data. Therefore, in the present invention, a space 12 is provided between the temperature sensor 1 and the bottom plate 5. The space 12 is mainly used to prevent the temperature from being easily transmitted from the temperature sensor due to heat conduction when the temperature sensor 1 senses the temperature. Lowered, resulting in inaccurate measured temperature.

In the present invention, in order to make the resistance sensitive to temperature changes, the thermistor 11 of the temperature sensor 1 uses a high thermal resistance coefficient (TCR). Another point is that if the length of the material is increased, the resistance value is also With the increase, when the temperature changes, increasing the length of the thermistor 11 can accumulate the amount of change in resistance. Therefore, the thermistor 11 of the present invention uses multiple folding methods to increase the length of the thermistor 11 , And can reduce the size. The humidity sensor 2 is made of polymer material 21 after absorbing water,

Page 9 200531124 V. Description of the invention (6)

The dielectric value of the polymer material 21 is changed, and then the capacitance value is used to measure humidity. The present invention is a capacitive humidity sensor 2, and a polymer material 21 is further spaced between the two electrodes. The characteristic of the polymer material 21 is that it will change the dielectric value when it absorbs moisture. In this embodiment, the polymer material 21 used is polyimide (P ο 1 y I mide). In addition, it can also be used Benzenecyclobutene (BCB, Benzocyclobutene), and an electrode is arranged above and below the polymer material 21, and two electrodes like a fence are provided on the upper electrode 22, and two electrodes are formed together with the lower electrode to form two The capacitors are connected in series, and the upper electrode 2 2 is designed in a grid shape, which mainly allows the polymer material 21 to have a larger area to contact the outside environment to increase the response speed of the humidity sensor 2.

The pressure sensor 3 senses pressure by using a change in piezoresistance 31. First, the pressure sensor 3 uses an ion doping on a silicon substrate 4 to make the doped portion a semiconductor. A semiconductor can be regarded as a piezoresistance. It also uses the resistance change of the semiconductor to sense the pressure change, but how can there be a reference pressure to compare the external pressure? Therefore, in the present invention, a space 32 is provided on the bottom surface of the pressure sensor 3, and then the space 5 is sealed by the bottom plate 5, so that the pressure sensor 3 has a reference pressure. At this time, one side of the film is used as a reference. Pressure, the other side is the external pressure, so when the external pressure is less than the reference pressure, the film shape will bulge outward, and the piezoresistance 31 on the film will be deformed to cause its resistance value to change. This is used to measure the pressure, and the piezoresistance 31 is designed to be located at the edge of the film, because when the external pressure changes, the film is deformed. At this time, the maximum stress occurs at the edge of the film, and the piezoresistance 3 1 at the edge of the film will produce Maximum resistance change.

Page 10 200531124 V. Description of the invention (7) The above-mentioned piezoresistance 3 1 is formed by re-doping silicon substrate 4 with ions. The silicon substrate 4 currently used is generally divided into N-type and P-type. (P-type), different materials doped with different ions, such as silicon material substrate 4 is N-type, the doped metal ions are hole-type ions, such as boron (B), etc., if the silicon material substrate 4 is P type, the metal ions doped are electronic type metal ions, such as phosphorus (P), Kun (As) or antimony (Sb).

The temperature, humidity and pressure sensor 3 can be completed in a consistent integrated process, and the process can be matched with the CMOS process, that is, the signal processing circuit a is first manufactured by the CMOS process, and then processed directly on the signal The circuit a makes a sensor. Please refer to the third diagrams (a) to (Q) for the process steps of the present invention. The following describes the manufacturing process of the sensor, including: Step 1: Use silicon substrate 4 to remove the surface pollution sources of the substrate using standard cleaning procedures. Generally, there are many sources of pollution in the air, such as human hair, dander, and dust in the air. All will be contaminated on the surface of the silicon substrate 4. If these pollution sources are not removed during the manufacturing process, the product yield will be seriously affected. Therefore, the surface must be cleaned by standard cleaning procedures during the initial steps of the process. Increase adhesion.

Step 2: Deposit (Deposition) silicon dioxide 4 1 on the shixi material substrate 4 as an insulating layer and a doping shield. The silicon dioxide 41 is mainly used to prevent the silicon substrate 4 from being doped. During the process, contamination with doped ions occurs at unnecessary doping positions. Step 3: open a hole in the deposited silicon dioxide 41, the position of the hole

Page 11 200531124 V. Description of the invention (8) This is the position to be doped. Generally, the opening is achieved by an etching process. Today's etching process is generally divided into wet etching and dry etching. The so-called wet etching uses chemical The solution reacts with the material to achieve the purpose of etching. Another dry etching method uses an ion beam and a gaseous chemical etchant to generate a chemical reaction on the material to consume the material to be etched.

Step 4: Doping ions at the openings to form the piezoresistance 31 of the pressure sensor 3. The piezoresistance 31 is formed by doping the silicon substrate 4 with ions. The silicon substrate 4 used today is generally divided into It is N-type and P-type. The ions doped with different materials are different. If the silicon substrate 4 is N-type, the doped metal ions are hole-type metal ions. For example, if boron (B) is used, if the silicon substrate 4 is P-type, the doped metal ions are electronic metal ions, such as phosphorus (P), arsenic (As), or antimony (Sb). Step 5: Deposit silicon nitride 42 as a protective layer in step 7 of the subsequent silicon etching process. Step 6: Make an etching hole on the back of the silicon substrate 4 as in the process of Step 3. Step 7: The silicon substrate 4 is etched to produce an isolation space 1 2 and 3 2 of the pressure sensor 3 and the temperature sensor 1. The isolation spaces 1 2 and 3 2 are reference pressures of the pressure sensor 3 and Thermally conductive isolated space of the temperature sensor 1.

Step 8: Remove the silicon nitride 4 2 and silicon dioxide 41 1 on the back surface to prepare an anode joint between the back surface of the silicon substrate 4 and the bottom plate 5. Step 9: Anodically bond the silicon substrate 4 to the bottom plate 5. The anodic bonding is traditionally used to join metal and glass substrates.

Page 12 200531124 V. Description of the invention (9) High temperature program (higher than 100 ° C) to form a mixture of metal oxide and glass on the interface, which can provide high-strength bonding effect; another way In order to use a large electric field instead of high temperature, the junction temperature can be reduced to about 400 ° C. The principle is that the positive ions in the glass are driven by the negative electrode, and a large electric field is formed on the interface, which promotes the formation of both sides. To connect, the general steps are: (1) placing the glass on silicon oxide (2) heating to about 400 degrees Celsius (t :) (3) adding a positive pressure of about 120 volts (V) to the silicon crystal On the circle. Step 10: Deposit metal 1 as the resistance material of the temperature sensor 1 and the lower electrode 2 3 of the humidity sensor 2. In this embodiment, nickel metal may be deposited, and the deposited metal may be electron-steamed. Plating or sputtering method. Step 11: Coating Photoresist 43. Step 12: The photoresist 4 3 above the piezoresistance 31 position develops an etching hole. Step 13: The silicon nitride 4 2 above the piezoresistance 31 is etched and removed, and after the etching is removed, the coated photoresist 43 is removed with a solvent. Step 14: Re-coat the polymer material 21. In this embodiment, the polymer material 21 is polyimide, and other polymer materials 21 such as phenylcyclobutene (BCB , Benzocyclobutene). Step 15: Develop the polymer material 21 as the sensor for the humidity sensor 2. The wet film and the thermistor 1 1 protective film for the temperature sensor 1. Step sixteen: deposit metal 244. In this embodiment, copper or gold may be deposited. Step 17: Etching the photoresist 4 3 and developing the etching hole, and then etching

200531124 V. Description of the invention (10) Metal 2 4 4 to form the upper electrode 2 2 of the humidity sensor, the measurement points of the temperature sensor 1 and the wires of the pressure sensor 3, because the material is copper or gold, Can reduce signal loss and reduce interference. The above-mentioned metal deposition is achieved by an electronic grab deposition method or a sputtering method. Therefore, the present invention can use the consistent integration process to produce three types of sensors, which saves a lot of process time and cost. The process of the present invention is compatible with the CMOS process. Therefore, after the signal processing circuit a is completed, Make sensors directly to reduce costs. Because the present invention uses micro-electromechanical technology to make the sensor, its volume is quite small, the space it takes up is very small, and the energy consumed is also relatively small. It can use air conditioning systems for general homes, companies, and hospitals. In order to control the pressure, temperature and humidity in the room, and to cooperate with the automatic control of the air-conditioning system, the environment can be adjusted to an environment with a small temperature gradient and appropriate pressure and humidity. If the present invention is applied to medical treatment, because its volume is quite small, it can be directly made into a device, which can be directly used in the human body to measure blood pressure, pulse and temperature. It can immediately directly monitor some changes in the human body to promptly use it People pay attention to their physical condition, so the application of the invention can be described as quite wide. The above are only used to explain the better implementation of this creation, and are not intended to restrict the creation in any form. Therefore, any modification or change related to this creation under the same spirit of creation, They should still be included in the scope of protection of this creative intention.

200531124 Brief description of the drawings The first diagram is a structural diagram showing the present invention. The second figure is a combination diagram of a sensor and a signal processing circuit of the present invention. The third figures (a) to (q) are diagrams showing the process steps of the present invention. [Description of component symbols] (1) Temperature sensor (1 1) Thermistor (1 2) Space (2) Humidity sensor

(21) Polymer material (22) Upper electrode (23) Lower electrode (3) Pressure sensor (31) Piezoresistance (3 2) Space (4) Silicon substrate (4 1) Silicon dioxide (4 2 ) Silicon Nitride (43) Photoresist (44) Metal II

(5) Backplane (a) Signal processing circuit

Page 15

Claims (1)

200531124 VI. Application Patent Scope 1. A sensor integrating temperature, humidity and pressure, comprising: a silicon substrate and a bottom plate, and three micro-electro-mechanical processes are used to make three sensing elements on the substrate, namely temperature and humidity And pressure sensor; the temperature sensor uses a thermistor to change the resistance due to temperature changes to sense the temperature, and the temperature sensor has a space from the bottom plate; the humidity sensor uses a polymer After the material absorbs moisture, the dielectric value of the polymer material changes, and then the capacitance value is used to measure the humidity; the pressure sensor uses a change in piezoresistance to sense pressure, and the pressure sensor and the The floor has a space. 2. The integrated temperature, humidity and pressure sensor according to item 1 of the scope of patent application, wherein the thermistor is a metal. 3. The integrated temperature, humidity and pressure sensor according to item 2 of the scope of patent application, wherein the metal is nickel. 4. The integrated temperature, humidity and pressure sensor according to item 1 of the scope of patent application, wherein the polymer material is polyimide. 5. According to the integrated temperature, humidity and pressure sensor described in item 1 of the scope of the patent application, wherein the southern molecular material is BCB 'Benzocyclobutene 〇6. According to the first scope of the patent application, An integrated temperature, humidity and pressure sensor, wherein the piezoresistance is doped with ions on a silicon substrate. 7. The integrated temperature, humidity and pressure sensor according to item 6 of the scope of the patent application, wherein the ion is a hole-type ion. 200531124 6. Scope of patent application 8. According to the integrated temperature, humidity and pressure sensor described in item 7 of the scope of patent application, the hole-type ion is boron. 9. The integrated temperature, humidity and pressure sensor according to item 6 of the scope of the patent application, wherein the ion is an electronic ion. I 0. The integrated temperature, humidity, and pressure sensor according to item 9 of the scope of the patent application, wherein the electron-type ion is phosphorus. II. The integrated temperature, humidity and pressure sensor according to item 9 of the scope of the patent application, wherein the electron-type ion is arsenic. 1 2. According to the integrated temperature, humidity and pressure sensor described in item 9 of the scope of the patent application, the electronic ion is antimony. 1 3. According to the integrated temperature, humidity and pressure sensor described in item 1 of the scope of patent application, wherein the bottom plate is glass. 1 4. A method of manufacturing a sensor that integrates temperature, humidity, and pressure, including: Step 1: Use a standard cleaning procedure to remove a source of surface contamination from the silicon substrate; Step 2: Deposit silicon dioxide on the silicon substrate As an insulating layer; step three: opening holes in the deposited silicon dioxide >; step four: doping metal ions at the opening positions to form a piezoresistance of the pressure sensor; Step 5: deposit silicon nitride; Step 6: open an etching hole on the back of the silicon substrate; Step 7: etch the substrate of the test material to create an isolation space between the pressure sensor and the temperature sensor; Page 17 200531124 6. Scope of patent application Step 8: Remove back silicon nitride and silicon dioxide; Step 9: Anodically bond the silicon substrate to the bottom plate; Step 10: Deposit metal 1 as the resistance of the temperature sensor Materials and electrodes under the humidity sensor; Step 11: Coating the photoresist; Step 12: Developing the etching hole on the photoresist above the piezoresistance position; Step 13: Etching the silicon nitride above the piezoresistance And after the etching is removed, the applied photoresist is removed; step 14: coating and molecular materials, Step 15: Develop the polymer material as the moisture-sensitive film of the humidity sensor and the thermistor protective film of the temperature sensor; Step 16: Deposit Metal II; Step 17: Apply photoresist and develop the remaining material After the hole is engraved, the second metal is engraved to form the electrode on the humidity sensor, the measurement point of the temperature sensor and the wire of the pressure sensor; the temperature, humidity and pressure sensor are processed in one process The process is completed and the process is matched with the C M 0 S process, that is, the signal processing circuit is first manufactured using the C M 0 S process, and then the sensor is directly manufactured in the signal processing circuit. 15. The manufacturing method of the integrated temperature, humidity and pressure sensor according to item 14 of the scope of the patent application, wherein the ion is a hole-type ion. 16. According to the method of the scope of the patent application, item 15 A method for manufacturing a sensor integrating temperature, humidity, and pressure, wherein the hole-type ion is boron. 1 7. According to the integrated temperature, humidity and pressure described in item 14 of the scope of patent application Page 18 200531124 VI. Application scope Patent manufacturing method of force sensor, in which the ion is an electronic ion. 18. The manufacturing method of the integrated temperature, humidity and pressure sensor according to item 17 in the scope of the patent application, wherein the electronic ion is phosphorus. 19. The manufacturing method of the integrated temperature, humidity and pressure sensor according to item 17 of the scope of the patent application, wherein the electronic ion is arsenic. 20. The method for manufacturing a sensor integrating temperature, humidity, and pressure according to item 17 of the scope of the patent application, wherein the electronic ion is antimony. 2 1. The method for manufacturing a sensor integrating temperature, humidity and pressure according to item 14 of the scope of the patent application, wherein the first metal is nickel. 2 2. The manufacturing method of the integrated temperature, humidity and pressure sensor according to item 14 of the scope of the patent application, wherein the second metal is copper. 2 3. The manufacturing method of the integrated temperature, humidity and pressure sensor according to item 14 of the scope of the patent application, wherein the metal 2 is gold. 2 4. The manufacturing method of the integrated temperature, humidity and pressure sensor according to item 14 of the scope of the patent application, wherein the polymer material is polyimide. 25. The manufacturing method of the integrated temperature, humidity and pressure sensor according to item 14 of the scope of the patent application, wherein the polymer material is BCB 5 Benzocyclobutene 〇 2 6. According to the patent application The manufacturing method of the integrated temperature, humidity, and pressure sensor described in the item 14 of the scope, wherein the bottom plate is glass. 27. The manufacturing method of the integrated temperature, humidity, and pressure sensor according to item 14 of the scope of the patent application, wherein the deposited metal is deposited by electronic deposition. Page 19 200531124 Page 20