Micro-fluidic chip for efficient separation of miniature gas chromatograph

Abstract

The invention relates to a micro-fluidic chip for efficient separation of a micro gas chromatograph, the micro-fluidic chip for efficient separation of the micro gas chromatograph comprises a silicon wafer, a water cooling structure arranged above the silicon wafer and a heating element and a temperature measuring element arranged below the silicon wafer, and the water cooling structure is manufactured by adopting the micro-nano machining bonding process. And the water cooling structure is tightly connected with the upper part of the silicon wafer in an attached manner by adopting an anodic bonding mode. According to the micro-fluidic chip for efficient separation of the micro-gas chromatograph, the water cooling structure is prepared on the silicon wafer in a bonding manner, so that the micro-fluidic chip for efficient separation of the micro-gas chromatograph is applied to form a micro-chromatographic column through the water cooling structure after analysis is completed under the condition that the size of the chip is not increased; the cooling waiting time during continuous analysis can be greatly shortened, the power consumption is reduced, and the problem of high power consumption caused by poor cooling effect due to the fact that the power consumption is reduced by a natural cooling mode of an existing miniature gas chromatograph is solved.

Description

Technical Field

[0001] The present application relates to the technical field of chromatographic column integrated chips, and in particular to a microfluidic chip for efficient separation of micro gas chromatographs. Background Art

[0002] Gas chromatography is widely used, such as in medical research and pharmaceuticals, clinical applications, national defense, aviation, industrial online analysis, petrochemicals, environmental monitoring, food safety and other fields. Gas chromatography GC is the preferred method for analyzing volatile organic compounds (VOC) mixtures in the air. It uses carrier gas (such as nitrogen, hydrogen, etc.) as the mobile phase. When the components of the mixture sample flow through the stationary phase, the components in the mixed sample are separated due to the differences in boiling point, molecular size, polarity and adsorption properties.

[0003] Traditional gas chromatographs cannot meet the needs of on-site, real-time, and rapid detection due to their large size and high power consumption. Therefore, micro gas chromatographs have been favored by the market and are widely used. Under certain circumstances, micro gas chromatographs need to work continuously and continuously sample and analyze to obtain test results. Micro gas chromatographs are usually powered by batteries, so the power demand of the micro gas chromatograph is crucial. Without affecting the chromatographic resolution and detection effect, reducing the power consumption of the entire detection process is the main means to extend the working time of the micro gas chromatograph, and it is also a policy requirement for energy conservation and emission reduction.

[0004] At present, with the development of micromotor technology, micro-nano processing technology has reduced the size (mass) of related equipment components, so the heating power demand has been reduced accordingly. However, the power of gas chromatographs is still very high, which is a limiting factor in achieving high performance, miniaturization and long-term operation. Existing gas chromatographs have the defect of short sustainable working time.

[0005] The micro gas chromatography column is a key component of the gas chromatograph. The micro gas chromatography column includes a microchannel with a specific layout. The inner surface of the microchannel is coated (or filled with) with a material used as a stationary phase. The stationary phase adsorbs analytes of different components in the mixed gas to different degrees. The difference in adsorption will lead to inconsistent resolution rates of different analytes, resulting in different migration rates of different components to the end, which plays a separation role. Existing products heat the micro gas chromatography column to effectively separate the analytes of different components in the mixed gas. Since the micro chromatographic column itself is extremely small (usually micrometer-level), existing market products all use natural cooling to achieve the cooling of the micro chromatographic column. Summary of the invention

[0006] The present application provides a microfluidic chip for efficient separation in a micro gas chromatograph, which is used to solve the technical problem that the existing micro gas chromatograph reduces power consumption by natural cooling, but the cooling effect is poor, resulting in high power consumption.

[0007] In order to achieve the above objectives, this application provides the following technical solutions:

[0008] On the one hand, a microfluidic chip for efficient separation in a micro gas chromatograph is provided, comprising a silicon wafer, a water cooling structure disposed above the silicon wafer, and a heating element and a temperature measuring element disposed below the silicon wafer, wherein the water cooling structure is manufactured by a micro-nano machining bonding process, and the water cooling structure is tightly connected to the top of the silicon wafer by anodic bonding.

[0009] Preferably, the micro-nano machining bonding process includes:

[0010] Obtaining two pieces of glass to be manufactured and glass parameters, and making alignment marks on the two pieces of glass to be manufactured to obtain corresponding marked glass; the glass parameters include the pipe diameter;

[0011] Performing an alignment operation on the two pieces of the marked glass using a photolithography device according to the alignment mark to obtain a workpiece to be bonded;

[0012] Acquiring bonding parameters, and performing a bonding operation on the workpiece to be bonded using a bonding device according to the bonding parameters to obtain a bonded workpiece;

[0013] The pipeline is constructed on the bonded workpiece by sandblasting or chemical etching according to the pipeline diameter of the glass parameters to obtain a water-cooling structure containing a plurality of water-cooling pipelines.

[0014] Preferably, the bonding parameters include minimum temperature, minimum voltage, applied pressure and bonding time.

[0015] Preferably, the minimum temperature is 500° C.; and / or, the minimum voltage is 700 V; and / or, the applied pressure is 5000 N; and / or, the bonding time is 30 min.

[0016] Preferably, the pipe diameter is 300um~1000um.

[0017] Preferably, the thickness of each piece of glass to be manufactured is 300um~650um.

[0018] Preferably, a plurality of microchannels are provided on the silicon wafer.

[0019] Preferably, the length of each of the microchannels is 150um to 300um; and / or the thickness of the silicon wafer is 400um to 650um.

[0020] Preferably, the heating element and the temperature measuring element are both arranged under the silicon wafer by magnetron sputtering or electron beam evaporation; and / or, the heating element is a thermode for heating the silicon wafer, and the temperature measuring element is a thermistor for measuring the temperature of the silicon wafer in real time.

[0021] Preferably, the thermoelectrode and the thermal resistor are both made of aluminum, platinum or gold; and / or the thickness of the thermoelectrode and the thermal resistor are both 100um~500um.

[0022] The microfluidic chip for efficient separation of a micro gas chromatograph and the micro-nano machining bonding process include the following steps: obtaining two pieces of glass to be manufactured and glass parameters, making alignment marks on the two pieces of glass to be manufactured, and obtaining corresponding marked glass; the glass parameters include pipe diameters; performing an alignment operation on the two pieces of marked glass by using a photolithography device according to the alignment marks, and obtaining a workpiece to be bonded; obtaining bonding parameters, and performing a bonding operation on the workpiece to be bonded by using a bonding device according to the bonding parameters, and obtaining a bonded workpiece; and constructing a pipe on the bonded workpiece by sandblasting or chemical etching according to the pipe diameter of the glass parameters, and obtaining a water-cooling structure containing a plurality of water-cooling pipes.

[0023] The microfluidic chip for efficient separation of the micro gas chromatograph includes a silicon wafer, a water cooling structure disposed above the silicon wafer, and a heating element and a temperature measuring element disposed below the silicon wafer. The water cooling structure is manufactured by the above-mentioned micro-nano machining bonding process, and the water cooling structure is tightly connected to the top of the silicon wafer by anodic bonding.

[0024] It can be seen from the above technical scheme that the present application has the following advantages: the micro-chromatographic column chip integrated with the chip silicon wafer and the water-cooling structure constructed by the micro-nano processing bonding process can be cooled quickly, and the micro-chromatographic column chip is applied to a micro-gas chromatograph to improve the cooling effect of the micro-gas chromatograph, thereby solving the technical problem that the existing micro-gas chromatograph reduces power consumption through natural cooling, but the cooling effect is poor, resulting in high power consumption.

[0025] The microfluidic chip for efficient separation of the micro gas chromatograph prepares a water-cooling structure by bonding on a silicon wafer. Without increasing the volume of the chip, the chromatograph can achieve rapid cooling of the micro chromatographic column formed by the microfluidic chip for efficient separation of the micro gas chromatograph through the water-cooling structure after the analysis is completed, which can greatly shorten the cooling waiting time during continuous analysis and reduce power consumption. This solves the technical problem that the existing micro gas chromatograph reduces power consumption by natural cooling, but the cooling effect is poor, resulting in high power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0027] Figure 1 This is a schematic diagram of the structure of a microfluidic chip for efficient separation of a micro gas chromatograph as described in an embodiment of the present application;

[0028] Figure 2 This is a flow chart of the steps of the micro-nano machining bonding process described in an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to make the purpose, features, and advantages of the invention of this application more obvious and easy to understand, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described below are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] In the description of the embodiments of the present application, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0031] In the embodiments of the present application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0032] Explanation of patent terms:

[0033] A photolithography machine is a machine that prints target structure patterns onto a substrate such as a silicon wafer. Its mechanism is similar to the photo printing process.

[0034] A bonding machine is an instrument used in the field of micro-nano processing.

[0035] Electron beam evaporation is a type of physical vapor deposition. Different from traditional evaporation methods, electron beam evaporation uses the coordination of electromagnetic fields to accurately bombard the target material in the crucible with high-energy electrons, causing it to melt and then deposit on the substrate.

[0036] Magnetron sputtering is a type of physical vapor deposition (PVD). The general sputtering method can be used to prepare metals, semiconductors, insulators and other materials, and has the advantages of simple equipment, easy control, large coating area and strong adhesion.

[0037] The embodiment of the present application provides a microfluidic chip for efficient separation in a micro gas chromatograph, which solves the technical problem that the existing micro gas chromatograph reduces power consumption by natural cooling, but the cooling effect is poor, resulting in high power consumption.

[0038] Figure 1 This is a schematic diagram of the structure of the microfluidic chip for efficient separation of the micro gas chromatograph described in the embodiment of the present application. Figure 1 21 is a water cooling pipe.

[0039] like Figure 1 As shown, an embodiment of the present application provides a microfluidic chip for efficient separation of a micro gas chromatograph, including a silicon wafer 10, a water-cooling structure 20 disposed above the silicon wafer 10, and a heating element 30 and a temperature measuring element 40 disposed below the silicon wafer 10. The water-cooling structure 20 is manufactured by a micro-nano machining bonding process, and the water-cooling structure 20 is tightly connected to the top of the silicon wafer 10 by an anodic bonding method.

[0040] It should be noted that the microfluidic chip for efficient separation of the micro gas chromatograph has a water cooling structure for rapid cooling made by micro-nano machining bonding process on top of the silicon wafer 10, which greatly shortens the waiting time for cooling the chromatographic column of the microfluidic chip for efficient separation of the micro gas chromatograph during continuous analysis, and at the same time can increase the theoretical plate number of the chromatographic column of the microfluidic chip for efficient separation of the micro gas chromatograph, further improve the separation capacity of the micro chromatographic column of the microfluidic chip for efficient separation of the micro gas chromatograph, and reduce energy consumption. The microfluidic chip for efficient separation of the micro gas chromatograph combines the micro-nano machining bonding process to overcome the high product process requirements. At the same time, in order to realize the water cooling solution, a large amount of experimental data analysis, verification, and adjustment of technical solutions have also been carried out.

[0041] In an embodiment of the present application, the microfluidic chip for efficient separation of the micro gas chromatograph is tightly connected to the water cooling structure by micro-nano-processed anodic bonding on the silicon wafer. Without increasing the volume of the chip, the chromatograph can achieve rapid cooling of the micro chromatographic column composed of the microfluidic chip for efficient separation of the micro gas chromatograph through the water cooling structure after the analysis is completed, which can greatly shorten the cooling waiting time during continuous analysis and reduce power consumption. At the same time, the water cooling structure can also increase the number of theoretical plates of the micro chromatographic column composed of the microfluidic chip for efficient separation of the micro gas chromatograph, thereby increasing the separation capacity of the micro chromatographic column.

[0042] The present application provides a microfluidic chip for efficient separation of a micro gas chromatograph, comprising a silicon wafer, a water cooling structure disposed above the silicon wafer, and a heating element and a temperature measuring element disposed below the silicon wafer, the water cooling structure being manufactured by the above-mentioned micro-nano machining bonding process, and the water cooling structure being closely connected to the top of the silicon wafer by an anodic bonding method. The micro gas chromatograph for efficient separation of the micro fluidic chip is prepared by bonding the water cooling structure on the silicon wafer, and without increasing the volume of the chip, the chromatograph can realize rapid cooling of the micro chromatographic column formed by the micro fluidic chip for efficient separation of the micro gas chromatograph through the water cooling structure after the analysis is completed, which can greatly shorten the waiting time for cooling during continuous analysis, realize power consumption reduction, and solve the technical problem that the existing micro gas chromatograph reduces power consumption by natural cooling, and the poor cooling effect leads to high power consumption.

[0043] like Figure 1 As shown, in one embodiment of the present application, a plurality of microchannels 11 are disposed on the silicon wafer 10 .

[0044] It should be noted that if the thickness of the silicon wafer 10 is less than 400um, the capillary of the microfluidic channel 11 cannot be connected. If the thickness of the microfluidic channel 11 exceeds 650um, the processing difficulty of the microfluidic channel 11 will increase. Therefore, the thickness of the silicon wafer can be selected as 400um~650um. In this embodiment, the silicon wafer 10 has a microfluidic channel 11 etched in a square, circular or diamond shape using a dry etching process. If the length of the microfluidic channel 11 is less than 150um, the flow rate of the gas molecules flowing into the microfluidic channel 11 is too fast, which will reduce the separation ability of the micro-chromatographic column. If the length of the microfluidic channel 11 is greater than 300um, the diameter of the microfluidic channel 11 and the capillary connected to the microfluidic channel 11 are quite different, which will cause a large flow rate difference of the gas molecules flowing into the microfluidic channel 11 under the same pressure, and will also affect the separation ability of the micro-chromatographic column. Therefore, the length of each microfluidic channel can be 150um~300um.

[0045] like Figure 1As shown, in one embodiment of the present application, the heating element 30 and the temperature measuring element 40 are both arranged under the silicon wafer 10 by magnetron sputtering or electron beam evaporation; and / or, the heating element 30 is a thermode for heating the silicon wafer 10, and the temperature measuring element 40 is a thermistor for measuring the temperature of the silicon wafer 10 in real time.

[0046] It should be noted that the thermocouple and the thermal resistor are both made of aluminum, platinum or gold. The thickness of the thermocouple and the thermal resistor can be 100um~500um. In the present embodiment, the thermocouple is used to realize the programmed temperature rise of the microfluidic chip for efficient separation of the micro gas chromatograph. The thermal resistor is used to realize the real-time temperature measurement of the silicon wafer 10. The thermocouple is a metal used in the commonly used micro-nano processing, and the thermocouple and the thermal resistor are arranged below the silicon wafer 10 through a processing technology (such as magnetron sputtering, electron beam evaporation, etc.). The materials for making the thermocouple and the thermal resistor include but are not limited to gold Au, platinum Pt, aluminum Al, etc.

[0047] Figure 2 This is a flow chart of the steps of the micro-nano machining bonding process described in an embodiment of the present application.

[0048] like Figure 2 As shown, in one embodiment of the present application, the micro-nano machining bonding process includes:

[0049] S1. Obtain two pieces of glass to be manufactured and glass parameters, perform alignment marking on the two pieces of glass to be manufactured, and obtain corresponding marked glass; the glass parameters include the pipe diameter.

[0050] It should be noted that in step S1, the first step is to obtain the water cooling structure construction materials and parameters, and the second step is to make alignment marks on the glass to be produced. The glass parameters include the pipe diameter of the water cooling pipe and the thickness of the glass to be produced.

[0051] In the embodiment of the present application, the diameter of the pipe can be selected to be 300um~1000um. The thickness of each piece of glass to be produced can be selected to be 300um~650um.

[0052] It should be noted that when the thickness of the glass to be produced is less than 300um, the diameter of the water cooling pipe of the water cooling structure is too small to achieve effective cooling. When the thickness of the glass to be produced exceeds 650um, the processing difficulty will increase.

[0053] S2. Align the two pieces of marked glass using a photolithography device according to the alignment marks to obtain workpieces to be bonded.

[0054] It should be noted that the photolithography equipment can be a photolithography machine. In step S2, the alignment mark of the marking glass obtained in step S1 is used to perform an alignment operation through the photolithography machine to obtain a workpiece to be bonded.

[0055] S3. Acquire bonding parameters, and perform bonding operations on the workpiece to be bonded using bonding equipment according to the bonding parameters to obtain a bonded workpiece.

[0056] It should be noted that the bonding device can be selected as a bonding machine. In step S3, the first step is to obtain bonding parameters, and the second step is to use a bonding machine to perform bonding operations on the workpieces to be bonded according to the bonding parameters to obtain bonded workpieces. In this embodiment, the bonding parameters include minimum temperature, minimum voltage, applied pressure and bonding time. Among them, the minimum temperature can be 500°C; the minimum voltage can be 700V; the applied pressure can be 5000N; and the bonding time can be 30min.

[0057] S4. According to the pipe diameter of the glass parameters, the bonded workpiece is pipe-constructed by sandblasting or chemical etching to obtain a water-cooling structure containing several water-cooling pipes.

[0058] It should be noted that in step S4, a plurality of water-cooling pipes are constructed on the bonded workpiece according to the pipe diameter obtained in step S1 to obtain a water-cooling structure.

[0059] In the embodiment of the present application, the micro-nano machining bonding process first makes alignment marks on two pieces of glass to be manufactured, and aligns one piece of glass to be manufactured with another piece of glass to be manufactured through a photolithography machine. Then, the bonding operation is performed on the bonding machine by raising the temperature to a minimum temperature of 500°C, applying a voltage to a minimum voltage of more than 700V, applying a pressure of 5000N, and pressing the key for 30 minutes, thereby achieving bonding between the two pieces of glass to be manufactured.

[0060] It should be noted that the micro-nano machining bonding process is compatible with conventional MEMS manufacturing processes, and can well realize the integration of water-cooling structure and chip silicon wafer microfluidic chip and mass-processing of microfluidic chip with this structure. The traditional water-cooling structure adopts a mechanical structure and cannot be mass-produced like chip silicon wafer integrated circuits. The bonding of the water-cooling structure and the chip usually uses thermal conductive glue to achieve heat conduction. If the bonding is not dense, it will affect its cooling performance. At the same time, the water cooling volume made by the mechanical structure is large, which will increase the volume of the chip, thereby increasing its power consumption.

[0061] The micro-nano machining bonding process provided by the embodiment of the present application includes: obtaining two pieces of glass to be manufactured and glass parameters, making alignment marks on the two pieces of glass to be manufactured, and obtaining corresponding marked glass; the glass parameters include pipe diameter; aligning the two pieces of marked glass through photolithography equipment according to the alignment marks to obtain a workpiece to be bonded; obtaining bonding parameters, using bonding equipment to perform bonding operations on the workpiece to be bonded according to the bonding parameters to obtain a bonded workpiece; constructing a pipe for the bonded workpiece through sandblasting or chemical corrosion according to the pipe diameter of the glass parameters to obtain a water-cooled structure containing several water-cooled pipes. The water-cooled structure constructed by the micro-nano machining bonding process and the micro-chromatographic column chip integrated with the chip silicon wafer can quickly cool down, and this micro-chromatographic column chip is applied to a micro gas chromatograph to improve the cooling effect of the micro gas chromatograph.

[0062] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A microfluidic chip for efficient separation of micro gas chromatograph, characterized in that: It includes a silicon wafer, a water cooling structure arranged above the silicon wafer, and a heating element and a temperature measuring element arranged below the silicon wafer. The water cooling structure is made by a micro-nano machining bonding process, and the water cooling structure is tightly connected to the top of the silicon wafer by an anodic bonding method.

2. The microfluidic chip for efficient separation of micro gas chromatograph according to claim 1, characterized in that: The micro-nano machining bonding process comprises: Obtaining two pieces of glass to be manufactured and glass parameters, and making alignment marks on the two pieces of glass to be manufactured to obtain corresponding marked glass; the glass parameters include the pipe diameter; Performing an alignment operation on the two pieces of the marked glass using a photolithography device according to the alignment mark to obtain a workpiece to be bonded; Acquiring bonding parameters, and performing a bonding operation on the workpiece to be bonded using a bonding device according to the bonding parameters to obtain a bonded workpiece; The pipeline is constructed on the bonded workpiece by sandblasting or chemical etching according to the pipeline diameter of the glass parameters to obtain a water-cooling structure containing a plurality of water-cooling pipelines.

3. The microfluidic chip for efficient separation of micro gas chromatograph according to claim 2, characterized in that: The bonding parameters include minimum temperature, minimum voltage, applied pressure and bonding time.

4. The microfluidic chip for efficient separation of micro gas chromatograph according to claim 3, characterized in that: The minimum temperature is 500° C.; and / or, the minimum voltage is 700 V; and / or, the applied pressure is 5000 N; and / or, the bonding time is 30 min.

5. The microfluidic chip for efficient separation of micro gas chromatograph according to claim 2, characterized in that: The thickness of each piece of glass to be manufactured is 300um~650um.

6. The microfluidic chip for efficient separation of micro gas chromatograph according to claim 2, characterized in that: The diameter of the pipeline is 300um~1000um.

7. The microfluidic chip for efficient separation of micro gas chromatograph according to claim 1, characterized in that: A plurality of microchannels are arranged on the silicon chip.

8. The microfluidic chip for efficient separation of micro gas chromatograph according to claim 7, characterized in that: The length of each of the microchannels is 150um to 300um; and / or the thickness of the silicon wafer is 400um to 650um.

9. The microfluidic chip for efficient separation of micro gas chromatograph according to claim 1, characterized in that: The heating element and the temperature measuring element are both arranged below the silicon wafer by magnetron sputtering or electron beam evaporation; and / or, the heating element is a thermode for heating the silicon wafer, and the temperature measuring element is a thermistor for measuring the temperature of the silicon wafer in real time.

10. The microfluidic chip for efficient separation of micro gas chromatograph according to claim 9, characterized in that: The thermode and the thermal resistor are both made of aluminum, platinum or gold; and / or the thickness of the thermode and the thermal resistor is 100um-500um.

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