A microfluidic DNA synthesis chip and its manufacturing method

Abstract

The present invention provides a microfluidic DNA synthesis chip and a manufacturing method thereof, including an integrated circuit layer, a microfluidic layer, and a top layer stacked in sequence from bottom to top. The integrated circuit layer has a transistor array and an addressing and decoding circuit. The transistor has a metal electrode with a polymer self-assembled layer connected to its upper surface. The microfluidic layer has microcavities corresponding one by one to the metal electrodes. During the DNA synthesis process, under the control of the peripheral circuit, any number of metal electrodes are selected through the addressing and decoding circuit to generate the required stable voltage within a specified time period, causing the components in the solution introduced into the microfluidic layer to undergo an electrolysis reaction to generate hydrogen ions, and causing a deprotection reaction and a coupling reaction to occur in the solution. The structural design of the microfluidic layer can confine the hydrogen ions generated at each site, avoiding mutual interference between sites caused by the diffusion of hydrogen ions, and eliminating the need to take other measures to prevent the diffusion of hydrogen ions, effectively reducing the complexity and manufacturing cost of the chip, and achieving high density and high throughput.

Description

Technical Field

[0001] The present invention belongs to the technical fields of biology, microfluidics and integrated circuits, and relates to a microfluidic DNA synthesis chip and a manufacturing method thereof. Background Art

[0002] DNA is an essential unit for studying the genetic mechanism of living organisms, and the central dogma also intuitively expounds the core position of the genetic information of DNA in research such as life activities and biodiversity. DNA uses A / T / C / G bases as information carrier units and stores information through different arrangements of bases. Therefore, it is very necessary to study the combined base sequences rather than individual free bases, just like studying the 0 / 1 sequence combinations that form information-bearing files rather than individual bits. DNA synthesis technology is a means of developing free-combined free bases into DNA strands carrying information, and has very important scientific significance.

[0003] The application scope of DNA synthesis includes but is not limited to DNA data storage, synthetic biology, and disciplines related to life information such as transcriptomics and genomics. Among them, DNA data storage is a technology that uses bases as information units and combines bases in a certain order to store information. Human society has entered the big data era, with a huge amount of data showing an exponential growth trend. Compared with all known technical means, DNA data storage has key advantages such as high storage density and long data preservation time, and is of great significance for alleviating the pressure brought by the exponentially explosive growth of data volume. Therefore, DNA is considered to be a future storage medium with great potential.

[0004] In recent years, DNA data storage has shown a rapid development trend. However, compared with modern hard disk storage, the DNA data storage capacity is still a very low value. Therefore, DNA storage technology is still a long way from real practical applications. This is because the key steps in the DNA storage process, namely DNA synthesis and sequencing, are restricted by their own technical development levels, and their speeds and costs are much lower than existing storage technologies. Further comparing synthesis and sequencing technologies, the biggest bottleneck in DNA data storage lies in DNA synthesis. For DNA synthesis technology, the throughput index is very important because an increase in throughput represents a decrease in cost and an increase in speed. Therefore, the research and development of high-throughput DNA synthesis technology plays a fundamental promoting role in realizing DNA data storage.

[0005] The existing DNA synthesis technologies can be classified into the following several types: column-type oligonucleotide chemical synthesis method, inkjet printing method, photo-deprotection chemical synthesis method, electro-deprotection chemical synthesis method, and enzymatic synthesis method.

[0006] The columnar oligonucleotide chemical synthesis method is the most basic and traditional automated DNA synthesis technology. Its process is divided into four steps: deprotection, coupling, capping, and oxidation. However, due to its bulky synthesis instrument, huge raw material storage containers, and transportation pipelines, it is very difficult to achieve a very high throughput, and the highest throughput can only reach about one thousand.

[0007] The inkjet printing method is the most successful commercialized synthesis instrument at present. Its principle is similar to the columnar oligonucleotide chemical synthesis method. By using a large-scale nozzle droplet array to realize parallel transportation of raw materials, the synthesis throughput is greatly improved. However, due to the printing accuracy problem of its mechanical nozzle and the limitation of droplet size, it is very difficult to further increase the synthesis density.

[0008] The photo-deprotection chemical synthesis method uses a microlens array or a mask plate to deprotect photosensitive protecting groups. The other processes except deprotection are the same as those of the traditional synthesis method. Due to the complex manufacturing of the microlens array, the large number of mask plates used, the high cost, and being limited by light diffraction, scattering, and halos, etc., the potential for throughput improvement is limited. The latest optical devices have the possibility of higher density, but due to their great manufacturing difficulty, complex manufacturing, much higher cost than transistors, and the density improvement is not large compared to transistors.

[0009] Electrochemical deprotection is also only different from the traditional chemical synthesis method in the deprotection step, and the other steps are the same. The principle of electro-deprotection is to generate acid through an electrochemical reaction to remove the protecting group on the base, and then perform coupling, capping, and oxidation. Since the most important technical requirement is to control the voltage change in the synthesis environment, it has high compatibility with conventional integrated circuit design and manufacturing. However, the current existing technical level is still relatively limited in throughput, and at the same time, it is necessary to solve the problem of the mutual influence of reaction reagents between different synthesis units.

[0010] Therefore, how to provide a microfluidic DNA synthesis chip and its manufacturing method to achieve high throughput and high density while reducing the complexity of the control unit in the synthesis chip and reducing the manufacturing cost has become an important technical problem that needs to be solved urgently by those skilled in the art.

[0011] It should be noted that the above introduction of the technical background is only for the convenience of clearly and completely explaining the technical solution of the present application and facilitating the understanding of those skilled in the art. It cannot be considered that the above technical solutions are well-known to those skilled in the art just because these solutions are described in the background art part of the present application. Summary of the Invention

[0012] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a microfluidic DNA synthesis chip and a manufacturing method thereof, which are used to solve the problems that the existing DNA synthesis devices are complex, have high manufacturing costs, and cannot meet the performance requirements of high throughput and high density.

[0013] To achieve the above purpose and other related purposes, the present invention provides a microfluidic DNA synthesis chip, including:

[0014] A microfluidic layer, including a liquid inlet, a liquid inlet main channel, a capillary valve channel, a liquid outlet main channel, and a liquid outlet that are connected in sequence. The liquid inlet main channel and the liquid outlet main channel both extend in the Y direction and are spaced apart in the X direction. The capillary valve channel extends in the X direction. The number of the capillary valve channels is multiple, and the multiple capillary valve channels are arranged at intervals in the Y direction. The Y direction is perpendicular to the X direction. The capillary valve channel includes a first capillary valve unit and a second capillary valve unit that are alternately connected in the X direction. Both the first capillary valve unit and the second capillary valve unit include a main path, a microchamber, a capillary valve, and a bypass. In each capillary valve unit, the inlet of the microchamber is connected to the outlet of the main path, the outlet of the microchamber is connected to the inlet of the capillary valve, and the inlet of the bypass is connected to the side wall of the main path. The outlet of the bypass of the first capillary valve unit is connected to the inlet of the main path of the second capillary valve unit, and the outlet of the capillary valve of the first capillary valve unit is connected to the side wall of the bypass of the second capillary valve unit;

[0015] An integrated circuit layer, located below the microfluidic layer. The integrated circuit layer includes a transistor array and an addressing and decoding circuit connected to the transistor array. The transistor array includes a plurality of transistor units arranged in an array. Each transistor unit has a metal electrode, and the metal electrodes correspond to the microchambers one by one. Each metal electrode is exposed in the corresponding microchamber;

[0016] A top layer, located on the microfluidic layer and covering the liquid inlet main channel, the capillary valve channel, and the liquid outlet main channel. The top layer includes a liquid inlet through hole and a liquid outlet through hole. The liquid inlet through hole is connected to the liquid inlet, and the liquid outlet through hole is connected to the liquid outlet.

[0017] Optionally, the bypass includes a horizontal portion extending in the X direction and a vertical portion extending in the Y direction. In each capillary valve unit, the inlet of the vertical portion is connected to the side wall of the main path, and the inlet of the horizontal portion is connected to the outlet of the vertical portion.

[0018] Optionally, the axis of the main path in the X direction, the geometric center of the microchamber, and the axis of the capillary valve in the X direction are located on a straight line.

[0019] Optionally, the width of the main path is equal to that of the bypass path, and is 0.4 to 0.9 times the distance between the two farthest points of the microcavity in the Y direction; the length of the main path is 0.5 to 2 times the distance between the two farthest points of the microcavity in the X direction; the width of the capillary valve is less than 0.1 times the width of the main path; the length of the capillary valve is 0.5 to 2 times the distance between the two farthest points of the microcavity in the X direction.

[0020] Optionally, the bottom surface area of the microcavity is 1 to 10 times the cross-sectional area of the metal electrode.

[0021] Optionally, the transistor unit includes a substrate, a source electrode, a drain electrode, a gate electrode, an insulating layer, and a metal electrode. The source electrode and the drain electrode are located on the upper surface layer of the substrate. The gate electrode is located on the upper surface of the substrate. The insulating layer is located on the upper surface of the substrate and covers the gate electrode. The metal electrode is located on the upper surface of the insulating layer.

[0022] Optionally, the transistor unit includes a capacitive structure. One of the source electrode and the drain electrode and the gate electrode are electrically connected to the addressing and decoding circuit. The other of the source electrode and the drain electrode is electrically connected to the metal electrode. The metal electrode serves as one of the plates of the capacitive structure. The other plate of the capacitive structure includes the substrate or a metal layer parallel to the metal electrode and located in the insulating layer.

[0023] Optionally, the addressing and decoding circuit includes at least one of a two-dimensional addressing circuit and a multi-dimensional addressing circuit higher than two-dimensional.

[0024] Optionally, when the addressing and decoding circuit is two-dimensional, the addressing and decoding circuit includes a row addressing circuit and a column addressing circuit. The drain electrodes of the transistor units in the same row are connected in series and electrically connected to an output port of the row addressing circuit. The gate electrodes of the transistor units in the same column are connected in series and electrically connected to an output port of the column addressing circuit; or, the source electrodes of the transistor units in the same row are connected in series and electrically connected to an output port of the row addressing circuit. The gate electrodes of the transistor units in the same column are connected in series and electrically connected to an output port of the column addressing circuit; or, the drain electrodes of the transistor units in the same column are connected in series and electrically connected to an output port of the column addressing circuit. The gate electrodes of the transistor units in the same row are connected in series and electrically connected to an output port of the row addressing circuit; or, the source electrodes of the transistor units in the same column are connected in series and electrically connected to an output port of the column addressing circuit. The gate electrodes of the transistor units in the same row are connected in series and electrically connected to an output port of the row addressing circuit.

[0025] Optionally, the material of the top layer includes at least one of polymethyl methacrylate, polydimethylsiloxane, and glass; the material of the microfluidic layer includes at least one of polymethyl methacrylate, polydimethylsiloxane, glass, and silicon; the material of the metal electrode includes at least one of gold and platinum.

[0026] Optionally, the integrated circuit layer includes a dynamic random access memory structure.

[0027] The present invention also provides a method for manufacturing a microfluidic DNA synthesis chip, including the following steps:

[0028] Provide a composite layer structure, the composite layer structure includes a microfluidic layer and a top layer located on the microfluidic layer;

[0029] Provide an integrated circuit layer;

[0030] Bond the side of the composite layer structure having the microfluidic layer to the integrated circuit layer;

[0031] Wherein, the microfluidic layer includes a liquid inlet, a liquid inlet main channel, a capillary valve channel, a liquid outlet main channel, and a liquid outlet that are connected in sequence. The liquid inlet main channel and the liquid outlet main channel both extend in the Y direction and are spaced apart in the X direction. The capillary valve channel extends in the X direction. The number of the capillary valve channels is multiple, and the multiple capillary valve channels are arranged at intervals in the Y direction. The Y direction is perpendicular to the X direction. The capillary valve channel includes a first capillary valve unit and a second capillary valve unit that are alternately connected in the X direction. The first capillary valve unit and the second capillary valve unit both include a main path, a microchamber, a capillary valve, and a bypass. In each capillary valve unit, the inlet of the microchamber is connected to the outlet of the main path, the outlet of the microchamber is connected to the inlet of the capillary valve, and the inlet of the bypass is connected to the side wall of the main path. The outlet of the bypass of the first capillary valve unit is connected to the inlet of the main path of the second capillary valve unit, and the outlet of the capillary valve of the first capillary valve unit is connected to the side wall of the bypass of the second capillary valve unit;

[0032] The integrated circuit layer includes a transistor array and an addressing and decoding circuit connected to the transistor array. The transistor array includes a plurality of transistor units arranged in an array. Each transistor unit has a metal electrode, and the metal electrodes correspond to the microchambers one by one. Each metal electrode is exposed in the corresponding microchamber;

[0033] The top layer covers the liquid inlet main channel, the capillary valve channel, and the liquid outlet main channel and includes a liquid inlet through hole and a liquid outlet through hole. The liquid inlet through hole is communicated with the liquid inlet, and the liquid outlet through hole is communicated with the liquid outlet.

[0034] Optionally, the formation of the composite layer structure includes the following steps:

[0035] Provide a substrate, the substrate including an upper surface and a lower surface which are oppositely arranged;

[0036] Pattern the substrate from the upper surface of the substrate to obtain the liquid inlet, the liquid inlet main channel, the capillary valve channel, the liquid outlet main channel and the liquid outlet;

[0037] Pattern the substrate from the lower surface of the substrate to obtain the liquid inlet through hole and the liquid outlet through hole;

[0038] Wherein, the layer of the substrate having the liquid inlet, the liquid inlet main channel, the capillary valve channel, the liquid outlet main channel and the liquid outlet is used as the microfluidic layer, and the layer of the substrate having the liquid inlet through hole and the liquid outlet through hole is used as the top layer.

[0039] Optionally, the formation of the composite layer structure includes the following steps:

[0040] Provide a carrier substrate, form a photoresist layer on the carrier substrate, and pattern the photoresist layer to obtain an opening with a preset shape;

[0041] Form a molding layer by an inverse molding method, the molding layer covering the photoresist layer and filling into the opening;

[0042] Planarize the upper surface of the molding layer and heat-cure the molding layer;

[0043] Peel the molding layer from the surfaces of the carrier substrate and the photoresist layer, wherein the side of the molding layer facing the photoresist layer is formed with the liquid inlet, the liquid inlet main channel, the capillary valve channel, the liquid outlet main channel and the liquid outlet;

[0044] Punch holes in the molding layer to obtain the liquid inlet through hole and the liquid outlet through hole;

[0045] Wherein, the layer of the molding layer having the liquid inlet, the liquid inlet main channel, the capillary valve channel, the liquid outlet main channel and the liquid outlet is used as the microfluidic layer, and the layer of the molding layer having the liquid inlet through hole and the liquid outlet through hole is used as the top layer.

[0046] Optionally, the formation of the composite layer structure includes the following steps:

[0047] Provide a substrate, the substrate including a stacked first substrate layer and a second substrate layer;

[0048] Pattern the first substrate layer from the surface of the first substrate layer far away from the second substrate layer to obtain the liquid inlet, the liquid inlet main channel, the capillary valve channel, the liquid outlet main channel and the liquid outlet;

[0049] Pattern the second substrate layer from the surface thereof away from the first substrate layer to obtain the liquid inlet through-holes and the liquid outlet through-holes;

[0050] Wherein, the first substrate layer serves as the microfluidic layer, and the second substrate layer serves as the top layer.

[0051] As described above, the microfluidic DNA synthesis chip and its manufacturing method of the present invention include an integrated circuit layer, a microfluidic layer and a top layer. The upper surface of the integrated circuit layer has an exposed metal electrode array. A polymer self-assembled layer is connected to the upper surface of the metal electrode. The synthesis chambers of the upper microfluidic DNA synthesis chip correspond to the metal electrodes one by one, and the metal electrodes are surrounded in the center of the chambers. During the DNA synthesis process, under the control of the peripheral circuit, through the integrated circuit, the addressing and decoding circuit of the chip is used to select any number of metal electrodes to generate the required stable voltage within a specified time period, so that the components in the solution introduced into the microfluidic layer undergo an electrolysis reaction to generate hydrogen ions, thereby causing a deprotection reaction and a coupling reaction to occur in the solution; the structure of the microfluidic layer can confine the hydrogen ions generated at each site, avoiding mutual interference between sites caused by the diffusion of hydrogen ions, and eliminating the need for an additional cathode protection circuit to reduce hydrogen ions to prevent diffusion, or adding an alkaline component to the synthesis raw material to neutralize hydrogen ions to prevent diffusion, greatly reducing the complexity and manufacturing cost of the synthesis chip, and further improving the synthesis density and throughput. The manufacturing method of the microfluidic DNA synthesis chip of the present invention can further reduce the device size, greatly increase the synthesis density, improve the utilization efficiency of the solution, reduce the DNA synthesis cost, realize high-throughput DNA synthesis, and has simple manufacturing process steps and can be mass-produced. Description of the Drawings

[0052] Figure 1 Shown is an exploded structural schematic diagram of the microfluidic DNA synthesis chip of the present invention.

[0053] Figure 2 Shown is a top view schematic diagram of the microfluidic layer in the microfluidic DNA synthesis chip of the present invention.

[0054] Figure 3 Shown is a top view schematic diagram of the capillary valve unit in the microfluidic layer of the microfluidic DNA synthesis chip of the present invention.

[0055] Figure 4 Shown is a three-dimensional structural schematic diagram of the integrated circuit layer in the microfluidic DNA synthesis chip of the present invention.

[0056] Figure 5 Shown is a cross-sectional schematic diagram of the transistor unit in the integrated circuit layer of the microfluidic DNA synthesis chip of the present invention.

[0057] Figure 6 Shown is a schematic circuit connection diagram of the integrated circuit layer in the microfluidic DNA synthesis chip of the present invention.

[0058] Figure 7 Shown is a top view schematic diagram of the microfluidic layer in the microfluidic DNA synthesis chip of the present invention after introducing an electrolyte through the liquid inlet during the electrochemically induced acidification process for DNA synthesis.

[0059] Figure 8 Shown is a top view schematic diagram of the microfluidic layer in the microfluidic DNA synthesis chip of the present invention during the process of introducing a protective gas through the liquid inlet during the electrochemically induced acidification process for DNA synthesis.

[0060] Figure 9 Shown is a top view schematic diagram of the microfluidic layer in the microfluidic DNA synthesis chip of the present invention after completely introducing a protective gas through the liquid inlet during the electrochemically induced acidification process for DNA synthesis.

[0061] Figure 10 Shown is a top view schematic diagram of the microfluidic layer in the microfluidic DNA synthesis chip of the present invention after introducing a protective gas through the liquid outlet after the completion of the electrochemically induced acidification process for DNA synthesis.

[0062] Figure 11 Shown is a cross-sectional schematic diagram of the structure obtained after forming the first photoresist layer in step A2 of Example 2 in the manufacturing method of the microfluidic DNA synthesis chip of the present invention.

[0063] Figure 12 Shown is a cross-sectional schematic diagram of the structure obtained after patterning the first photoresist layer in step A2 of Example 2 in the manufacturing method of the microfluidic DNA synthesis chip of the present invention.

[0064] Figure 13 Shown is a cross-sectional schematic diagram of the structure obtained after forming the microfluidic layer pattern in step A2 of Example 2 in the manufacturing method of the microfluidic DNA synthesis chip of the present invention.

[0065] Figure 14 Shown is a cross-sectional schematic diagram of the structure obtained after removing the first photoresist layer in step A2 of Example 2 in the manufacturing method of the microfluidic DNA synthesis chip of the present invention.

[0066] Figure 15 Shown is a cross-sectional schematic diagram of the structure obtained after forming the second photoresist layer in step A3 of Example 2 in the manufacturing method of the microfluidic DNA synthesis chip of the present invention.

[0067] Figure 16 Shown is a cross-sectional schematic diagram of the structure obtained after patterning the second photoresist layer to obtain the top layer pattern in step A3 of Example 2 in the manufacturing method of the microfluidic DNA synthesis chip of the present invention.

[0068] Figure 17 Schematic cross-sectional view of the structure obtained after forming the top layer pattern in step A3 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention in Example 2.

[0069] Figure 18 Schematic cross-sectional view of the structure obtained after removing the second photoresist layer in step A3 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention in Example 2.

[0070] Figure 19 Schematic cross-sectional view of the structure obtained after performing step S2 in Example 2 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention.

[0071] Figure 20 Schematic cross-sectional view of the structure obtained after performing step S3 in Example 2 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention.

[0072] Figure 21 Schematic cross-sectional view of the structure obtained after forming the photoresist layer in step B1 of Example 3 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention.

[0073] Figure 22 Schematic cross-sectional view of the structure obtained after patterning the photoresist layer in step B1 of Example 3 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention.

[0074] Figure 23 Schematic cross-sectional view of the structure obtained after performing step B2 in Example 3 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention.

[0075] Figure 24 Schematic cross-sectional view of the structure obtained after performing step B4 in Example 3 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention.

[0076] Figure 25 Schematic cross-sectional view of the structure obtained after performing step B5 in Example 3 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention.

[0077] Figure 26 Schematic cross-sectional view of the structure obtained after performing step S3 in Example 3 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention.

[0078] Figure 27 Schematic cross-sectional view of the structure obtained after performing step C1 in Example 4 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention.

[0079] Figure 28Schematic cross-sectional view of the structure obtained after forming the first photoresist layer in step C2 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention in Example 4.

[0080] Figure 29 Schematic cross-sectional view of the structure obtained after patterning the first photoresist layer in step C2 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention in Example 4.

[0081] Figure 30 Schematic cross-sectional view of the structure obtained after forming the microfluidic layer pattern in step C2 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention in Example 4.

[0082] Figure 31 Schematic cross-sectional view of the structure obtained after removing the first photoresist layer in step C2 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention in Example 4.

[0083] Figure 32 Schematic cross-sectional view of the structure obtained after forming the second photoresist layer in step C3 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention in Example 4.

[0084] Figure 33 Schematic cross-sectional view of the structure obtained after patterning the second photoresist layer in step C3 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention in Example 4.

[0085] Figure 34 Schematic cross-sectional view of the structure obtained after forming the top layer pattern in step C3 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention in Example 4.

[0086] Figure 35 Schematic cross-sectional view of the structure obtained after removing the second photoresist layer in step C3 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention in Example 4.

[0087] Figure 36 Schematic cross-sectional view of the structure obtained after performing step S3 in Example 4 of the method for fabricating a microfluidic DNA synthesis chip according to the present invention.

[0088] Element number description

[0089] 1 Top layer

[0090] 11 Liquid inlet through hole

[0091] 12 Liquid outlet through hole

[0092] 2 Microfluidic layer

[0093] 21 Liquid inlet

[0094] 22 Liquid inlet main channel

[0095] 23 Capillary valve channel

[0096] 231 Capillary valve unit

[0097] 2311 Main path

[0098] 2312 Bypass path

[0099] 23121 Vertical part

[0100] 23122 Horizontal part

[0101] 2313 Microcavity

[0102] 2314 Capillary valve

[0103] 232 First capillary valve unit

[0104] 233 Second capillary valve unit

[0105] 24 Liquid outlet main channel

[0106] 25 Liquid outlet

[0107] 3 Integrated circuit layer

[0108] 31 Transistor array

[0109] 311 Transistor unit

[0110] 3111 Substrate

[0111] 3112 Source electrode

[0112] 3113 Drain electrode

[0113] 3114 Gate electrode

[0114] 3115 Insulating layer

[0115] 3116 Metal electrode

[0116] 3117 Metal layer

[0117] 32 Addressing and decoding circuit

[0118] 321 Row addressing circuit

[0119] 322 Column addressing circuit

[0120] 33 Output port of addressing and decoding circuit

[0121] 4 Base material

[0122] 51, 54 First photoresist layer

[0123] 52, 55 Second photoresist layer

[0124] 53 Photoresist layer

[0125] 6 Carrier substrate

[0126] 7 Molding layer

[0127] 8 Substrate

[0128] 81 First substrate layer

[0129] 82 Second substrate layer

[0130] W1 to W5 Widths

[0131] L1 to L5 Lengths Detailed implementation manners

[0132] The following uses specific specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0133] Please refer to Figures 1 to 36 . It should be noted that the illustrations provided in this embodiment only schematically illustrate the basic concept of the present invention. Therefore, only the components related to the present invention are shown in the drawings, rather than being drawn according to the number, shape, and size of the components in actual implementation. The types, quantities, and proportions of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0134] Embodiment 1

[0135] This embodiment provides a microfluidic DNA synthesis chip. Please refer to Figure 1 , which shows a schematic exploded view of the microfluidic DNA synthesis chip, including a top layer 1, a microfluidic layer 2, and an integrated circuit layer 3.

[0136] Specifically, please refer to Figure 2, which shows a top view schematic diagram of the microfluidic layer 2 structure of this embodiment. The microfluidic layer 2 includes a liquid inlet 21, a main liquid inlet channel 22, a capillary valve channel 23, a main liquid outlet channel 24, and a liquid outlet 25 that are connected in sequence. The main liquid inlet channel 22 and the main liquid outlet channel 24 both extend in the Y direction and are spaced apart in the X direction. The capillary valve channel 23 extends in the X direction. The number of the capillary valve channels 23 is multiple, and the multiple capillary valve channels 23 are arranged at intervals in the Y direction. The Y direction is perpendicular to the X direction; the capillary valve channel 23 includes a first capillary valve unit 232 and a second capillary valve unit 233 that are alternately connected in the X direction. Please refer to Figure 3 , which shows a top view schematic diagram of the capillary valve unit of this embodiment. The first capillary valve unit 232 and the second capillary valve unit 233 both include a main path 2311, a microchamber 2313, a capillary valve 2314, and a bypass 2312. Please also refer to Figure 2 and Figure 3 , within each capillary valve unit 231, the inlet of the microchamber 2313 is connected to the outlet of the main path 2311, the outlet of the microchamber 2313 is connected to the inlet of the capillary valve 2314, and the inlet of the bypass 2312 is connected to the side wall of the main path 2311; in two adjacent capillary valve unit structures, the outlet of the bypass of the first capillary valve unit 232 is connected to the inlet of the main path of the second capillary valve unit 233, and the outlet of the capillary valve of the first capillary valve unit 232 is connected to the side wall of the bypass of the second capillary valve unit 233. In this application document, the inlets and outlets mentioned are all in terms of the liquid inlet or gas inlet direction from the liquid inlet 21 flowing to the liquid outlet 25.

[0137] As an example, please also refer to Figure 3 , the bypass 2312 includes a horizontal portion 23122 extending in the X direction and a vertical portion 23121 extending in the Y direction. Within each capillary valve unit 231, the inlet of the vertical portion 23121 is connected to the side wall of the main path 2311, and the inlet of the horizontal portion 23122 is connected to the outlet of the vertical portion 23121.

[0138] As an example, in the capillary valve unit 231 closest to the main liquid inlet channel 22 in the capillary valve channel 23, the inlet of the main path 2311 extends in the direction towards the main liquid inlet channel 22 and is connected to the main liquid inlet channel 22; in the capillary valve unit 231 closest to the main liquid outlet channel 24 in the capillary valve channel 23, the bypass 2312 further includes an extension portion ( Figure 2(not marked in the figure), the extension part is in an "L" shape or an inverted "L" shape, that is, the horizontal part and the vertical part of the bypass 2312 are in an "L" shape, then the extension part is in an inverted "L" shape; the horizontal part and the vertical part of the bypass 2312 are in an inverted "L" shape, then the extension part is in an "L" shape. In this capillary valve unit, the capillary valve 2314 is connected to the vertical part of the extension part, the outlet of the horizontal part 23122 is connected to the vertical part of the extension part, and the horizontal part 23122 of the extension part is connected to the total liquid outlet channel 24.

[0139] As an example, the axis of the main channel 2311 in the X direction, the geometric center of the microchamber 2313, and the axis of the capillary valve 2314 in the X direction are located on a straight line. The bottom surface shape of the microchamber 2313 includes, but is not limited to, a circular shape, an oval shape, a rectangular shape, a polygonal shape, and other irregular shapes, etc. In this embodiment, the bottom surface shape of the microchamber 2313 is a rectangle.

[0140] As an example, the width (W1) of the main channel 2311 is equal to the width (W2) of the bypass channel 2312, and is 0.4 to 0.9 times the distance (W4) between the two points farthest apart in the Y direction of the microcavity 2313; the length (L1) of the main channel 2311 is 0.5 to 2 times the distance (L4) between the two points farthest apart in the X direction of the microcavity 2313; the width (W5) of the capillary valve 2314 is less than 0.1 times the width (W1) of the main channel 2311; the length (L5) of the capillary valve 2314 is 0.5 to 2 times the distance (L4) between the two points farthest apart in the X direction of the microcavity 2313. In addition, in the bypass channel 2312, the width (W2) of the vertical portion 23121 is also equal to the width (W3) of the horizontal portion 23122, and the sum of the length (L3) of the horizontal portion 23122 and the width (W2) of the vertical portion 23121 is equal to the overall length of the capillary valve unit 231, while the length (L2) of the vertical portion 23121 is determined according to the design density and process requirements of the actual capillary valve unit. In this embodiment, in view of the fact that the bottom surface shape of the microcavity 2313 is rectangular, the distance between the two points farthest apart in the Y direction of the microcavity 2313 is the width of the microcavity 2313, and the distance between the two points farthest apart in the X direction of the microcavity 2313 is the length of the microcavity 2313. That is, the widths of the main channel 2311 and the bypass channel 2312 are 0.4 to 0.9 times the width of the microcavity 2313, and can be 0.5 times, 0.6 times, 0.7 times, 0.8 times; the length of the main channel 2311 is 0.5 to 2 times the length of the microcavity 2313, and can be 0.8 times, 1 time, 1.5 times, 1.8 times; the length of the capillary valve 2314 is 0.5 to 2 times the length of the microcavity 2313, and can be 0.8 times, 1 time, 1.5 times, 1.8 times.

[0141] As an example, the material of the microfluidic layer 2 includes at least one of polymethyl methacrylate, polydimethylsiloxane, glass, and silicon; the thickness range of the microfluidic layer 2 is 10 μm to 100 μm, and can be 30 μm, 50 μm, 80 μm. In this embodiment, the material of the microfluidic layer 2 is polydimethylsiloxane, and the thickness is 60 μm. The purpose of selecting polydimethylsiloxane is that it has relatively high transparency, is convenient for observation, has no autofluorescence and will not interfere with observation, has good biocompatibility, will not affect the experimental results, and has low cost and is easy to process.

[0142] Specifically, the structural design of the capillary valve unit 231 in the microfluidic layer 2 of the microfluidic DNA synthesis chip of this embodiment is as Figure 2 and Figure 3As shown, that is, in the same capillary valve unit 231, the capillary valve 2314 communicates with the microchamber 2313, and in adjacent capillary valve units 231, the capillary valve 2314 communicates with the bypass 2312. The capillary valve 2314 can ensure that the aqueous reaction solution experiences a large capillary resistance when flowing through the capillary valve 2314, while the isolation oil (or protective gas) can pass through smoothly. Thus, when the reaction solution is fed into the microfluidic layer 2 in the forward direction (along the liquid inlet direction, that is, from the liquid inlet 21), after the reaction solution fills the microchamber 2313, it flows into the next capillary valve unit 231 from the bypass 2312; after the water-phase reaction solution fills the chip, when the isolation oil or protective gas is introduced, the reaction solution in the microchamber 2313 cannot be discharged, and the droplets in the main channel 2311 and the bypass 2312 are discharged smoothly, thereby forming independent droplets in the microchamber 2313; after independent droplets are formed in the microchamber 2313 and the microfluidic layer 2 is filled with other isolation oil or protective gas, when the isolation oil or protective gas is fed into the chip in the reverse direction (against the liquid inlet direction, that is, from the liquid outlet 25), the droplets in the microchamber 2313 can be discharged sequentially one by one. The structural design of the microfluidic layer 2 can further reduce the device size, greatly improve the synthesis density, increase the use efficiency of the solution, reduce the synthesis cost, and achieve ultra-high-throughput rapid DNA synthesis.

[0143] Specifically, please refer to Figure 1 again. The top layer 1 is located on the microfluidic layer 2 and covers the liquid inlet main channel 22, the capillary valve channel 23, and the liquid outlet main channel 24. The top layer 1 includes a liquid inlet through hole 11 and a liquid outlet through hole 12. The liquid inlet through hole 11 communicates with the liquid inlet 21, and the liquid outlet through hole 12 communicates with the liquid outlet 25. The top layer 1 and the microfluidic layer 2 are integrally formed or tightly bonded together to ensure airtightness so that each structure in the microfluidic layer 2 can function.

[0144] As an example, the material of the top layer 1 includes at least one of polymethyl methacrylate, polydimethylsiloxane, and glass, and can also be other suitable insulating transparent materials; the thickness range of the top layer 1 is 0.1 cm to 3 cm, and it can be 0.5 cm, 1 cm, 1.5 cm, 2 cm, 2.5 cm; the cross-sectional shape of the top layer 1 includes but is not limited to circular, rectangular, polygonal, elliptical, and irregular shapes. In this embodiment, the material of the top layer 1 is polydimethylsiloxane, the cross-sectional shape is rectangular, and the thickness is 1.8 cm.

[0145] Specifically, the integrated circuit layer 3 is located below the microfluidic layer 2. Please refer to Figure 4 and Figure 6 in combination. Among them, Figure 4 shows a three-dimensional structural schematic diagram of the integrated circuit layer 3 structure of this embodiment. Figure 6A circuit connection schematic diagram showing the integrated circuit layer structure of this embodiment. The integrated circuit layer 3 includes a transistor array 31 and an addressing and decoding circuit 32 connected to the transistor array 31. The transistor array 31 includes a plurality of transistor units 311 arranged in an array. Each transistor unit 311 has a metal electrode 3116, and the metal electrodes 3116 correspond to the microcavities 2313 one by one. Each metal electrode 3116 is exposed in the corresponding microcavity 2313.

[0146] As an example, the bottom area of the microcavity 2313 is 1 to 10 times the cross-sectional area of the metal electrode 3116. The chamber of the microcavity 2313 can surround the metal electrode 3116. This unique structure can greatly slow down or prevent the self-diffusion of hydrogen ions, thereby restricting hydrogen ions within the chamber area, preventing the synthesis raw materials at each metal electrode site from interfering with each other due to diffusion flow, and there is no need to take other measures to limit the diffusion of hydrogen ions, such as using an additional cathodic protection circuit to reduce hydrogen ions to prevent their diffusion, or adding an alkaline component to the synthesis raw materials to neutralize hydrogen ions to prevent their diffusion, which can greatly reduce the complexity and manufacturing cost of the integrated circuit control chip.

[0147] As an example, the material of the metal electrode 3116 includes at least one of gold and platinum. The material of the metal electrode 3116 may also include other suitable conductive materials that allow the self-assembly of long-chain mercapto linker arms. During the application to DNA synthesis, a polymer self-assembled layer is connected to the upper surface of the metal electrode 3116, and oligonucleotide chains are synthesized on this polymer self-assembled layer.

[0148] As an example, please refer to Figure 5 which shows Figure 4 a cross-sectional schematic diagram of the transistor unit shown in. The transistor unit 311 includes a substrate 3111, a source electrode 3112, a drain electrode 3113, a gate electrode 3114, an insulating layer 3115, and a metal electrode 3116. The source electrode 3112 and the drain electrode 3113 are located on the upper surface layer of the substrate 3111. The gate electrode 3114 is located on the upper surface of the substrate 3111. The insulating layer 3115 is located on the upper surface of the substrate 3111 and covers the gate electrode 3114. The metal electrode 3116 is located on the upper surface of the insulating layer 3115. The source electrode 3112 and the drain electrode 3113 can be formed by N-type doping or P-type doping. The positions of the source electrode 3112 and the drain electrode 3113 can be interchanged, not limited to Figure 5 as shown in.

[0149] As an example, the integrated circuit layer 3 includes a Dynamic Random Access Memory (DRAM) structure, which can provide a source of electrical potential for the electrochemical reaction during DNA synthesis in the synthesis chip and can achieve precise control of reaction sites.

[0150] As an example, the transistor unit 311 includes a capacitive structure. One of the source 3112 and the drain 3113 and the gate 3114 are electrically connected to the addressing and decoding circuit 32. The other of the source 3112 and the drain 3113 is electrically connected to the metal electrode 3116. The metal electrode 3116 serves as one of the plates of the capacitive structure. The other plate of the capacitive structure includes the substrate 3111 or a metal layer 3117 parallel to the metal electrode 3116 in the insulating layer 3115. In this embodiment, as Figure 5 shown in the transistor unit 311, the source 3112 is connected to the addressing and decoding address through a metal interconnect structure. The drain 3113 is connected to the metal electrode 3116 through a metal interconnect structure to serve as one of the plates of the capacitive structure, and the metal layer 3117 serves as the other plate of the capacitive structure. The capacitive structure as described above thus becomes a capacitor device controlled by a transistor, providing a source of electrical potential for the subsequent electrochemical reaction in the microfluidic DNA synthesis chip.

[0151] Specifically, the capacitance parameters are ensured to be able to provide a stable voltage for the electrochemical reaction. The parameter selection is completed by calculating the capacitance size, charge and discharge time, and the equivalent impedance of the electrochemical reaction. The capacitance parameter selection scheme is as follows: Two important means in the entire implementation scheme are integrated circuit simulation and calculation formula: V = V0×(1 - e (-t / RC) ). Where R is the equivalent resistance, which is related to the specific integrated circuit and can be obtained by simulation. C is the capacitance, which can be obtained by the process and is one of the most important parameters of the present invention. The specific calculation process is as follows:

[0152] First, the charging time t c for a single transistor to charge to a specified voltage is obtained through simulation, u and the discharge time t s for the capacitor to discharge to a tolerable voltage. Thus, the time for all sites to charge to the specified voltage is t c = s / a×t s ≤ t u, after the charging of the capacitors at all sites is completed, the same operation can be performed in this cycle, which is called the refreshing operation, to replenish the discharged charge. This enables the approximate continuous replenishment of the charge consumed in the electrochemical reaction, thereby keeping the voltage relatively stable and allowing the electrochemical reaction to proceed stably.

[0153] Then, according to t s ≤t u , calculate the capacitance value that can keep the voltage relatively constant, because t s and t u are both related to the equivalent resistance R and capacitance C. The specific relationships are: t c =-RC×ln(1 - V e / V0), t s =s / a×t c , t u =-RC×ln(V m / V e ). Therefore, when the maximum charging voltage V e and the minimum tolerable voltage V m after discharge are determined, the capacitance C can be determined, where the equivalent resistance can be approximately given by circuit simulation.

[0154] Finally, according to the calculated capacitance value, use the formula C = εS / d to determine the selection of the capacitance shape during the manufacturing process.

[0155] As an example, the capacitance shape includes but is not limited to parallel plates, embedded, trenches, etc. The requirement for the capacitance size is to ensure the balance of the charge and discharge time and the voltage magnitude, that is, to ensure that a relatively stable voltage can be maintained during the electrochemical reaction, such as ensuring that the voltage can be recharged in the next cycle when the voltage after discharge is above 90% of the original voltage. The exposed metal electrode 3116 is one plate of the capacitor, and its shape includes but is not limited to circular, elliptical, rectangular, polygonal, and other irregular shapes, etc. The shape is jointly determined by the capacitance value calculated above and the process adopted, and the size is determined by the number of DNA strands assembled and the requirement for the capacitance size.

[0156] As an example, the addressing and decoding circuit 32 includes at least one of a two-dimensional addressing circuit and a multi-dimensional addressing circuit higher than two dimensions. During application, it is connected to a certain dimension or optional multiple sub-columns of a two-dimensional or multi-dimensional array, and the input is the encoded address. Each dimension output can simultaneously select a certain path or multiple paths, thereby realizing the parallel control of multiple sites. For example, when a certain row is selected, there is no conflict between the columns, so multiple columns of a certain row can be selected simultaneously.

[0157] As an example, please refer to again Figure 6, when the addressing and decoding circuit 32 is two-dimensional, the addressing and decoding circuit 32 includes a row addressing circuit 321 and a column addressing circuit 322. Combining Figure 5 and Figure 6 , the connection manner between the transistor array 31 and the addressing and decoding circuit 32 includes: the drains 3113 of the transistor units 311 in the same row are connected in series and electrically connected to an output port of the row addressing circuit 321, and the gates 3114 of the transistor units 311 in the same column are connected in series and electrically connected to an output port of the column addressing circuit 322; or, the sources 3112 of the transistor units 311 in the same row are connected in series and electrically connected to an output port of the row addressing circuit 321, and the gates 3114 of the transistor units 311 in the same column are connected in series and electrically connected to an output port of the column addressing circuit 322; or, the drains 3113 of the transistor units 311 in the same column are connected in series and electrically connected to an output port of the column addressing circuit 322, and the gates 3114 of the transistor units 311 in the same row are connected in series and electrically connected to an output port of the row addressing circuit 321; or, the sources 3112 of the transistor units 311 in the same column are connected in series and electrically connected to an output port of the column addressing circuit 322, and the gates 3114 of the transistor units 311 in the same row are connected in series and electrically connected to an output port of the row addressing circuit 321. The two-dimensional structure described above can realize the control of a large-scale transistor array 31 by an addressing and decoding circuit 32 with fewer pin numbers.

[0158] As an example, please refer to Figure 4 again. The integrated circuit layer 3 further includes a packaging structure ( Figure 4 not marked in the figure). The packaging structure packages the structural layer where the transistor array 31 is located and the addressing and decoding circuit 32 into a whole. The row addressing circuit 321 and the column addressing circuit 322 are led out through metal leads and connected to the output port 33 of the addressing and decoding circuit, and then connected to the PAD. Then, the various components in the integrated circuit layer 3 are packaged using the packaging structure to form the integrated circuit layer 3, which is subsequently installed on the designed PCB board. Then, the integrated circuit layer 3 is bonded to the microfluidic layer 2 to form a complete microfluidic DNA synthesis chip that can be controlled by an external computer or a single-chip microcomputer.

[0159] Specifically, the integrated circuit layer includes a transistor electrode array and an addressing and decoding circuit. The exposed metal electrodes above the transistor array are used to provide a potential for the electrochemical reaction. The addressing and decoding circuit can realize the addressability and controllability of the transistor electrode array. And due to the adoption of the structure of the DRAM integrated circuit, it can realize the precise control of the output of each electrode with fewer pin numbers. Due to the small size of the transistors and the mature design and manufacturing process, it can achieve the technical effect of relatively low-cost high-throughput.

[0160] Specifically, please refer to Figures 7 to 10 , which shows a schematic diagram of the DNA synthesis electroacidification process of the microfluidic DNA synthesis chip of this embodiment. The specific steps are as follows: As Figure 7 shown, an electrolyte solution is injected into the microfluidic layer from the liquid inlet 21 to fill the entire microfluidic layer; as Figure 8 shown, then air or a protective gas is introduced into the microfluidic layer from the liquid inlet 21; as Figure 9 shown, the electrolyte solution in the channel is discharged, so that the electrolyte solution only remains in the microcavities, forming mutually independent droplets. Under the control of the peripheral circuit, any specified multiple metal electrodes are selected and a stable voltage of 0.1V - 10V is generated within a specified time period, causing the components in the electrolyte solution to undergo an electrolysis reaction to generate hydrogen ions, thereby promoting a deprotection reaction in the solution. After the reaction lasts for a period of time, the power supply is stopped; as Figure 10 shown, a gas is introduced into the microfluidic layer from the liquid outlet 25, and the droplets are discharged in sequence. Then, acetonitrile is continuously injected into the chip from the liquid inlet 21 to rinse the entire microfluidic layer, and then other reaction solutions are introduced to carry out coupling, capping, and oxidation reactions.

[0161] The microfluidic DNA synthesis chip of the present invention realizes high throughput based on the confinement of the microfluidic structure and the control of the potential by the integrated circuit layer. It mainly realizes the generation of the required voltage (voltage range is 0.1V - 10V) on any multiple synthesis metal electrodes through the integrated circuit to regulate the addressing and decoding circuit of the chip, causing the components in the solution to undergo an electrolysis reaction to generate hydrogen ions, thereby enabling a deprotection reaction and a coupling reaction to occur in the solution. In this process, the structure in the microfluidic layer is used to confine the hydrogen ions generated at each site. When liquid is introduced, a protective gas is introduced to discharge the reaction solution in the passage. Due to the existence of the capillary valve, the reaction solution in the microcavities is retained to form independent droplets, thus confining the hydrogen ions generated by the electrolysis reaction of the reaction solution in the droplets and preventing interference with other sites. When changing the liquid, a protective gas can be introduced from the liquid outlet to discharge the reaction solution droplets in the microcavities into the channel and discharge them from the liquid inlet in sequence, avoiding the diffusion of hydrogen ions in the chip and interfering with other sites. The microfluidic DNA synthesis chip of the present invention can be applied to, but is not limited to, DNA synthesis devices such as DNA data storage, genomics, and transcriptomics. Compared with the prior art, in the present invention, the hydrogen ions are confined by the microfluidic structure. During the electrolysis reaction and liquid change processes, the droplets are independent of each other, completely avoiding the diffusion of hydrogen ions; there is no need to add alkaline components to the reaction solution or add an additional cathode to the integrated circuit regulated chip to neutralize (reduce) hydrogen ions, simplifying the complexity of the integrated circuit, reducing the equipment cost, and further improving the synthesis density and throughput.

[0162] Embodiment 2

[0163] This embodiment provides a method for fabricating a microfluidic DNA synthesis chip, which can be used to fabricate the microfluidic DNA synthesis chip described in Embodiment 1, and includes the following steps:

[0164] S1: Provide a composite layer structure, which includes a microfluidic layer and a top layer located on the microfluidic layer;

[0165] S2: Provide an integrated circuit layer;

[0166] S3: Bond the side of the composite layer structure having the microfluidic layer to the integrated circuit layer;

[0167] Wherein, the microfluidic layer includes a liquid inlet, a liquid inlet main channel, a capillary valve channel, a liquid outlet main channel and a liquid outlet which are connected in sequence. The liquid inlet main channel and the liquid outlet main channel both extend in the Y direction and are spaced apart in the X direction. The capillary valve channel extends in the X direction. The number of the capillary valve channels is multiple, and the multiple capillary valve channels are arranged at intervals in the Y direction. The Y direction is perpendicular to the X direction; the capillary valve channel includes a first capillary valve unit and a second capillary valve unit which are alternately connected in the X direction. Both the first capillary valve unit and the second capillary valve unit include a main path, a microchamber, a capillary valve and a bypass. In each capillary valve unit, the inlet of the microchamber is connected to the outlet of the main path, the outlet of the microchamber is connected to the inlet of the capillary valve, and the inlet of the bypass is connected to the side wall of the main path; the outlet of the bypass of the first capillary valve unit is connected to the inlet of the main path of the second capillary valve unit, and the outlet of the capillary valve of the first capillary valve unit is connected to the side wall of the bypass of the second capillary valve unit;

[0168] The integrated circuit layer includes a transistor array and an addressing and decoding circuit connected to the transistor array. The transistor array includes a plurality of transistor units arranged in an array. Each transistor unit has a metal electrode, and the metal electrodes correspond to the microchambers one by one, and each metal electrode is exposed in the corresponding microchamber.

[0169] The top layer covers the liquid inlet main channel, the capillary valve channel and the liquid outlet main channel and includes a liquid inlet through hole and a liquid outlet through hole. The liquid inlet through hole is communicated with the liquid inlet, and the liquid outlet through hole is communicated with the liquid outlet.

[0170] First, execute step S1 to provide a composite layer structure, which includes a microfluidic layer 2 and a top layer 1 located on the microfluidic layer 2.

[0171] As an example, please refer to Figures 11 to 18 , the formation of the composite layer structure includes steps A1 to A3:

[0172] Perform step A1 to provide a substrate 4, where the substrate 4 includes an upper surface and a lower surface that are oppositely arranged. The material of the substrate 4 includes glass and other suitable materials.

[0173] Perform step A2 to pattern the substrate 4 from the upper surface of the substrate 4 to obtain the liquid inlet 21, the liquid inlet main channel 22, the capillary valve channel 23, the liquid outlet main channel 24, and the liquid outlet 25. The specific process is as follows: As Figure 11 shown, spin-coat a first photoresist layer 51 on the upper surface (one side of the substrate 4) of the substrate 4 and then perform pre-baking; as Figure 12 shown, perform exposure and development based on the mask of the microfluidic layer 2 to pattern the first photoresist layer 51 to form the pattern of the microfluidic layer 2; as Figure 13 shown, perform the first etching to remove the substrate in a preset area to form the microfluidic layer 2; as Figure 14 shown, remove the first photoresist layer 51 after forming the microfluidic layer 2.

[0174] Perform step A3 to pattern the substrate 4 from the lower surface of the substrate 4 to obtain the liquid inlet through-hole 11 and the liquid outlet through-hole 12. The specific process is as follows: As Figure 15 shown, spin-coat a second photoresist layer 52 on the lower surface (i.e., the other side of the substrate 4) of the substrate 4 and then perform pre-baking; as Figure 16 shown, perform exposure and development based on the mask of the top layer 1 to pattern the second photoresist layer 52 to form the pattern of the top layer 1; as Figure 17 shown, perform the second etching to remove the substrate in a preset area to form the top layer 1; as Figure 18 shown, remove the second photoresist layer 52 after forming the top layer 1.

[0175] Among them, the layer of the substrate 4 that has the liquid inlet 21, the liquid inlet main channel 22, the capillary valve channel 23, the liquid outlet main channel 24, and the liquid outlet 25 serves as the microfluidic layer 2, and the layer of the substrate 4 that has the liquid inlet through-hole 11 and the liquid outlet through-hole 12 serves as the top layer 1.

[0176] Please refer to Figure 19 , perform step S2 to provide an integrated circuit layer 3. The integrated circuit layer 3 is prepared by using a conventional semiconductor manufacturing method.

[0177] Please refer to Figure 20 , perform step S3 to bond the side of the composite layer structure that has the microfluidic layer 2 to the integrated circuit layer 3.

[0178] The manufacturing method of the microfluidic DNA synthesis chip in this embodiment has a relatively mature manufacturing process and can achieve the technical effects of high-density and high-throughput of the microfluidic DNA synthesis chip at a relatively low manufacturing cost. In this embodiment, since the microfluidic layer and the top layer are formed by an integral molding method on the same substrate, good airtightness is ensured, which can ensure the data reliability and stability of the manufactured microfluidic DNA synthesis chip during the DNA synthesis process.

[0179] Embodiment III

[0180] This embodiment provides a manufacturing method of a microfluidic DNA synthesis chip. The difference from the manufacturing method in Embodiment II is that in this embodiment, the top layer and the microfluidic layer are mainly manufactured by an injection molding method, including the following steps:

[0181] S1: Provide a composite layer structure, where the composite layer structure includes a microfluidic layer and a top layer located on the microfluidic layer;

[0182] S2: Provide an integrated circuit layer;

[0183] S3: Bond the side of the composite layer structure with the microfluidic layer to the integrated circuit layer;

[0184] First, perform step S1 to provide a composite layer structure, where the composite layer structure includes a microfluidic layer 2 and a top layer 1 located on the microfluidic layer 2.

[0185] As an example, please refer to Figures 21 to 25 , the formation of the composite layer structure includes steps B1 to B5:

[0186] Perform step B1. As shown in Figure 21 , provide a carrier substrate 6 and form a photoresist layer 53 on the carrier substrate 6; as shown in Figure 22 , pattern the photoresist layer 53 to obtain an opening with a preset shape (the preset shape is set according to the pattern of the microfluidic layer). The material of the carrier substrate 6 includes but is not limited to silicon and glass. In this embodiment, the material of the carrier substrate 6 is silicon, and the model of the photoresist is SU-8. The structure composed of the carrier substrate 6 and the patterned photoresist layer 53 can be used as a mold for manufacturing the microfluidic layer 2. After the mold processing is completed, it can be reused, reducing the manufacturing cost.

[0187] Perform step B2. As shown in Figure 23 , use the injection molding method to form a molding layer 7. The molding layer 7 covers the photoresist layer 53 and fills into the opening. The material of the molding layer 7 includes but is not limited to polymethyl methacrylate, polydimethylsiloxane or other suitable materials. In this embodiment, the material of the molding layer 7 is polydimethylsiloxane.

[0188] Perform step B3 to flatten the upper surface of the molding layer 7 and heat-cure the molding layer 7.

[0189] Perform step B4, as Figure 24 shown, peel the molding layer 7 from the surface of the carrier substrate 6 and the photoresist layer 53, wherein a liquid inlet 21, a liquid inlet main channel 22, a capillary valve channel 23, a liquid outlet main channel 24, and a liquid outlet 25 are formed on one side of the molding layer 7 facing the photoresist layer 53.

[0190] Perform step B5, as Figure 25 shown, punch holes in the molding layer 7 to obtain the liquid inlet through hole 11 and the liquid outlet through hole 12.

[0191] Wherein, the layer of the molding layer 7 having the liquid inlet 21, the liquid inlet main channel 22, the capillary valve channel 23, the liquid outlet main channel 24, and the liquid outlet 25 serves as the microfluidic layer 2, and the layer of the molding layer 7 having the liquid inlet through hole 11 and the liquid outlet through hole 12 serves as the top layer 1.

[0192] Please refer to Figure 19 , perform step S2 to provide an integrated circuit layer 3. The integrated circuit layer 3 is prepared by a conventional semiconductor manufacturing method.

[0193] Please refer to Figure 26 , perform step S3 to bond the side of the composite layer structure having the microfluidic layer 2 to the integrated circuit layer 3.

[0194] The manufacturing method of the microfluidic DNA synthesis chip in this embodiment has a relatively mature manufacturing process and can achieve the technical effects of high-density and high-throughput of the microfluidic DNA synthesis chip at a relatively low manufacturing cost. In this embodiment, due to the use of the injection molding method to integrally form the microfluidics and the top layer, good airtightness is ensured, which can ensure the data reliability and stability of the manufactured microfluidic DNA synthesis chip during the DNA synthesis process; moreover, the processing process only requires one injection molding and there is no need for redundant alignment and lithography steps during the injection molding process, and the manufacturing process is simple and the yield is high.

[0195] Example 4

[0196] This embodiment provides a manufacturing method of a microfluidic DNA synthesis chip. The difference from the manufacturing methods in Embodiment 2 and Embodiment 3 is that the manufacturing method in this embodiment can manufacture top layers and microfluidic layers composed of different materials, including the following steps:

[0197] S1: Provide a composite layer structure, where the composite layer structure includes a microfluidic layer and a top layer located on the microfluidic layer;

[0198] S2: Provide an integrated circuit layer;

[0199] S3: Bond the side of the composite layer structure having the microfluidic layer to the integrated circuit layer;

[0200] First, perform step S1 to provide a composite layer structure, which includes a microfluidic layer 2 and a top layer 1 located on the microfluidic layer 2.

[0201] As an example, please refer to Figures 27 to 31 , the formation of the composite layer structure includes steps C1 to C3:

[0202] Perform step C1. As Figure 27 shown, provide a substrate 8, which includes a stacked first substrate layer 81 and a second substrate layer 82. The material of the first substrate layer 81 and the material of the second substrate layer 82 may be the same or different, and the materials include but are not limited to polymethyl methacrylate, polydimethylsiloxane, glass, etc. In this embodiment, the material of the first substrate layer 81 is different from the material of the second substrate layer 82. Among them, the material of the first substrate layer 81 is silicon, and the material of the second substrate layer 82 is glass. That is, the first substrate layer 81 is a silicon wafer, and the second substrate layer 82 is a glass wafer.

[0203] Perform step C2. Pattern the first substrate layer 81 from the surface of the first substrate layer 81 away from the second substrate layer 82 to obtain the liquid inlet 21, the liquid inlet main channel 22, the capillary valve channel 23, the liquid outlet main channel 24, and the liquid outlet 25. The specific process is as follows: As Figure 28 shown, spin-coat a first photoresist layer 54 on the surface of the first substrate layer 81 away from the second substrate layer 82 (i.e., the surface of the substrate 8 where the first substrate layer 81 is located), and then perform pre-baking. As Figure 29 shown, based on the mask of the microfluidic layer 2, perform exposure and development to pattern the first photoresist layer 54 to form the pattern of the microfluidic layer 2; as Figure 30 shown, perform the first etching to remove the first substrate layer 81 in a preset area to form the microfluidic layer 2; as Figure 31 shown, after forming the microfluidic layer 2, remove the first photoresist layer 81.

[0204] Perform step C3. Pattern the second substrate layer 82 from the surface of the second substrate layer 82 away from the first substrate layer 81 to obtain the liquid inlet through hole 11 and the liquid outlet through hole 12.

[0205] The specific process is as follows: As Figure 32As shown, after spin-coating a second photoresist layer 55 on the surface of the second substrate layer 82 away from the first substrate layer 81 (i.e., the surface of the substrate 8 where the second substrate layer 82 is located), pre-baking is performed; as Figure 33 shown, based on the top layer 1 mask, exposure and development are performed to pattern the second photoresist layer 55 to form the pattern of the top layer 1; as Figure 34 shown, a second etching is performed to remove the second substrate layer 82 in a preset area to form the top layer 1; as Figure 35 shown, after forming the top layer 1, the second photoresist layer 55 is removed. Among them, the first substrate layer 81 serves as the microfluidic layer 2, and the second substrate layer 82 serves as the top layer 1.

[0206] It should be noted that in this embodiment, after forming the substrate 8 from the first substrate layer 81 and the second substrate layer 82, patterning etching is sequentially performed on the upper surface and the lower surface of the substrate 8 to form the top layer 1 and the microfluidic layer 2. In other embodiments, the microfluidic layer 2 can be formed based on the first substrate layer 81, the top layer 1 can be formed based on the second substrate 82, and then the first substrate layer 81 and the second substrate layer 82 can be bonded.

[0207] Please refer to Figure 19 , perform step S2 to provide an integrated circuit layer 3. The integrated circuit layer 3 is prepared by using a conventional semiconductor manufacturing method.

[0208] Please refer to Figure 36 , perform step S3 to bond the side of the composite layer structure having the microfluidic layer 2 to the integrated circuit layer 3.

[0209] The manufacturing method of the microfluidic DNA synthesis chip in this embodiment has a relatively mature manufacturing process and can achieve the technical effects of high-density and high-throughput of the microfluidic DNA synthesis chip at a relatively low manufacturing cost. This embodiment can realize the manufacture of the top layer and the microfluidic layer of different materials, with a wider range of material selection, and can further reduce the manufacturing cost.

[0210] Embodiment Five

[0211] This embodiment provides a microfluidic layer 2 of one of the size specifications of the microfluidic DNA synthesis chip having the structure described in Embodiment One. The specific shape and size information are as follows:

[0212] The microfluidic layer 2 is a cuboid thin layer with a height of 60 μm. The microfluidic layer 2 has a liquid inlet 21 and a liquid outlet 25 that penetrate the microfluidic layer 2. Both the liquid inlet 21 and the liquid outlet 25 are circular, and the diameters of the liquid inlet 21 and the liquid outlet 25 are 480 μm.

[0213] Please refer toFigure 2 The liquid inlet main channel 22 and the liquid outlet main channel 24 extend along the Y direction from the liquid inlet 21 and the liquid outlet 25 respectively. The lengths of both the liquid inlet main channel 22 and the liquid outlet main channel 24 are 1000 μm, and the widths of both the liquid inlet main channel 22 and the liquid outlet main channel 24 are 240 μm. Between the liquid inlet main channel 22 and the liquid outlet main channel 24, 16 rows of capillary valve channels 23 are distributed in parallel at equal intervals. Each capillary valve channel 23 is composed of 8 groups of alternately connected first capillary valve units 231 and second capillary valve units 231, with a total of 16 capillary valve units 231. The shapes of the first capillary valve unit 231 and the second capillary valve unit 231 are mirror-symmetrical about the X direction (since the first capillary valve unit 231 and the second capillary valve unit 231 are alternately connected, it is not strictly mirror-symmetrical about the X direction. Here, the mirror symmetry only refers to the shape). The main path 2311 of the capillary valve unit 231 at the head of the capillary valve channel 23 (i.e., the capillary valve unit 231 closest to the liquid inlet main channel 22 in the capillary valve channel 23) extends towards the liquid inlet main channel 22 and is connected to the liquid inlet main channel 22. The capillary valve unit 231 at the tail of the capillary valve channel 23 (i.e., the capillary valve unit 231 closest to the liquid outlet main channel 24 in the capillary valve channel 23) is connected to the liquid outlet main channel 24 through the extension of the bypass 2312.

[0214] Each capillary valve unit 231 is composed of four parts: a main path 2311, a bypass 2312, a microchamber 2313, and a capillary valve 2314. The top view schematic diagram of the capillary valve unit 231 is as Figure 3 shown. In this embodiment, the microchamber 2313 is a square structure. The bypass 2312 includes a vertical part 23121 and a horizontal part 23122 that are interconnected. The vertical part 23121 and the horizontal part 23122 are in an "L" shape. Among them, the width (W1) of the main path 2311 is equal to the width (W2 or W3) of the bypass 2312, both being 15 μm. The length (L1) of the main path 2311 is 30 μm. The length (L2) of the vertical part 23121 is 30 μm. The width of the vertical part 23121 is equal to the width of the horizontal part 23122, both being 15 μm. The length (L3) of the horizontal part 23122 is 60 μm. The length (L4) and width (W4) of the microchamber 2313 are 30 μm. The width (W5) of the capillary valve 2314 is 1 μm. The length (L5) of the capillary valve 2314 is 15 μm.

[0215] It should be noted that Figure 2 the number of capillary valve channels 23 shown in Figure 2Mainly refer to Figure 2 the structure of the microfluidic layer 2 shown and the connection relationship between the structures for example.

[0216] Example Six

[0217] This example provides a specific structure of the integrated circuit layer in a microfluidic DNA synthesis chip. The structure of the integrated circuit layer is a DRAM-like integrated circuit. Please refer to Figures 4 to 6 , and the specific structure is as follows:

[0218] As Figure 4 and Figure 6 shown, in the DRAM integrated circuit layer, the number of transistor units that make up the transistor array is more than 10 million, and it is formed by a two-dimensional rectangular arrangement of 3163 rows and 3162 columns. Each row is connected one-to-one with each output port of the row addressing circuit. The number of input ports of the row addressing circuit is 12, and it can address and control 3163 output ports. Each column is connected one-to-one with each output port of the column addressing circuit. The number of input ports of the column addressing circuit is 134, and among them, 128-way parallel output control can be realized.

[0219] The specific transistor unit model, as Figure 5 shown, in which the metal electrode is a circular electrode with a thickness of several hundred nanometers, a radius of 4 μm, and a capacitance of 100 fF. In the two plates of the capacitor structure, silicon dioxide is used as the dielectric between the capacitor plates and the thickness of the silicon dioxide layer is 10 nm. Under these parameter conditions, the time for the capacitor structure of the transistor unit to be charged to the specified voltage is 79 ns, and the time for the entire array to be charged is 6 ms. During the 6 ms period, the discharge amount of the capacitor is less than 5% of the specified voltage, and a relatively stable voltage can be formed to ensure the progress of the electrochemical reaction.

[0220] It should be noted that the parameters used in this specific simulation are provided by the chip foundry, and the layout is drawn according to the calculated parameters. The layout design process adopts the most commonly used design process at present. During the design process, the code and layout design are respectively guided by pre-simulation and post-simulation to ensure that the requirements of the experiment can be achieved, and the manufacturing is the responsibility of the chip manufacturer.

[0221] Example Seven

[0222] This example provides a specific implementation process of the method for manufacturing the microfluidic DNA synthesis chip described in Example Three. The specific process is as follows:

[0223] (1) Lithography mask design and production

[0224] The pattern of the microfluidic layer 2 drawn using the L-Edit layout design software is printed out with high precision as multiple photomasks of the microfluidic layer 2. Each photomask has light-transmitting and light-impermeable patterns for forming the pattern of the microfluidic layer 2 in the exposure step.

[0225] (2) Mold processing

[0226] The mold required for fabricating the microfluidic layer 2 is prepared by lithographically processing a photoresist layer 53 on a carrier substrate 6. This mold can be reused after processing, and there is no need for an additional alignment lithography step during the mold casting process, making the manufacturing process simpler. The main steps include spin coating, soft bake, expose, post expose bake, develop, and hard bake on the carrier substrate 6 (the carrier substrate 7 in this embodiment is a silicon wafer) in sequence to obtain the photoresist layer 53 with a pattern complementary to that of the photomask. At this time, the combination of the photoresist layer 5 and the carrier substrate 6 constitutes the microfluidic layer mold. In this embodiment, the type of photoresist used for forming the photoresist layer 53 is SU-8, and the thickness of each structure in the corresponding microfluidic layer 2 in the microfluidic layer mold is 40 μm.

[0227] (3) Fabrication of the microfluidic layer and the top layer

[0228] The material for forming the microfluidic layer 2 is filled into the mold from the surface of the microfluidic layer mold with the pattern of the microfluidic layer 2 to obtain a molded layer 7. The upper surface of the molded layer 7 is planarized and the molded layer 7 is heated and cured. After the molded layer 7 is cured, the molded layer 7 is peeled off from the microfluidic layer mold. The side of the molded layer 7 facing the photoresist layer 53 has the structural pattern of the microfluidic layer 2, including the liquid inlet 21, the liquid inlet main channel 22, the capillary valve channel 23, the liquid outlet main channel 24, and the liquid outlet 25. At this time, the microfluidic layer 2 is basically formed. Then, holes are drilled in the molded layer based on the positions of the liquid inlet 21 and the liquid outlet 25 to obtain the liquid inlet through hole 11 and the liquid outlet through hole 12. The holes can be drilled from the surface where the liquid inlet 21 and the liquid outlet 25 are located, or on the opposite surface. In this embodiment, the filling material is preferably polydimethylsiloxane, and the thickness of the molded layer 7 is 1 cm.

[0229] (4) Overall device bonding

[0230] Bond the surface where the microfluidic layer 2 is located to the pre-fabricated integrated circuit layer 3. Use a plasma cleaner to perform plasma treatment on the surfaces of the two layers to be bonded, so that the microfluidic layer 2 and the integrated circuit layer 3 are bonded together. In this embodiment, SiO2-PDMS plasma bonding is adopted.

[0231] (5) Overall packaging of the device and connection of the device to the peripheral circuit

[0232] In actual application, the packaged device is soldered on the circuit board, and wires are led out from the chip pins and connected to the circuit control terminal. A level signal is output to the addressing and decoding circuit 32 through the control terminal, thereby controlling the DNA synthesis process.

[0233] Embodiment Eight

[0234] This embodiment provides an effect test on the actual implementation of oligonucleotide synthesis using a microfluidic DNA synthesis chip. The microfluidic DNA synthesis chip can be provided by any one of Embodiments 1 to 4. The specific steps are as follows:

[0235] (1) Connect the circuit

[0236] Solder the packaged chip on the circuit board, lead out wires from the chip pins, and connect them to control terminals such as Arduino. Write a single-chip microcomputer control program to convert the information to be synthesized into the site addresses that need to react, and output a level signal to the addressing and decoding circuit. The addressing and decoding circuit controls the sites to be synthesized to output a high level, so that the capacitive structure in the transistor unit is charged, providing a potential for the electrochemical reaction to generate acid. During this process, the hydrogen ions generated at the high-level sites will cause the protective group DMT to fall off, completing deprotection.

[0237] For example, first read the information to be stored, and divide the information according to the physical address of the designed integrated circuit. In this embodiment, it is divided into 10 million subsequence fragments or less; then, according to the base solvent introduced in this round, select the coding addresses where the subsequence fragments need to couple the same base and output a level. The addressing and decoding circuit will control the corresponding physical address sites to output a high level, charge the capacitor, and provide a potential for electro-generated acid.

[0238] (2) Prepare various solutions required for synthesizing oligonucleotides

[0239] The solutions required for synthesizing oligonucleotides include: piranha solution and an ethanol solution of 20 mM 6-mercapto-1-hexanol as the linker solution; acetonitrile solutions containing 0.10 M of each of the four phosphoramidite nucleotides A, T, C, G and 0.50 M ETT as the activation coupling solution; capping agents CAP A / CAP B; a 0.02 M iodine-water-pyridine-tetrahydrofuran oxidizing solution; an anhydrous acetonitrile solution containing 25 mM hydroquinone, 25 mM benzoquinone and 25 mM ammonium hexafluorophosphate as the electroacid solution; a 1:1 solution of anhydrous ethylenediamine and anhydrous ethanol as the ammonolysis solution.

[0240] (3) Oligonucleotide synthesis

[0241] In the first step, the exposed metal electrodes on the integrated circuit layer surface are treated with piranha solution, and the linker solution is introduced from the inlet to fill the entire chip. After incubating overnight, anhydrous ethanol solution and anhydrous acetonitrile solution are successively introduced from the inlet for rinsing.

[0242] In the second step, the activation coupling solution containing the phosphoramidite nucleotide corresponding to the synthesis sequence is introduced from the inlet, and the reaction is carried out for 120 s. Then, anhydrous acetonitrile solution is introduced from the inlet for rinsing.

[0243] In the third step, the capping agent is introduced from the inlet, and the reaction is carried out for 40 s. Then, anhydrous acetonitrile solution is introduced from the inlet for rinsing.

[0244] In the fourth step, the oxidizing solution is introduced from the inlet, and the reaction is carried out for 40 s. Then, anhydrous acetonitrile solution is introduced for rinsing.

[0245] In the fifth step, the electroacid solution is introduced from the inlet, and then nitrogen is introduced from the inlet to discharge the electroacid solution in the microcavities of the chip, forming droplets of the electroacid solution isolated from each other in each microcavity. The metal electrodes at the corresponding sites in the chip are selected by Arduino for power-on, with a voltage of 1.4 V. The power-on is stopped after 10 s of reaction.

[0246] In the sixth step, nitrogen is introduced from the outlet to discharge the droplets in the microcavities, and then anhydrous acetonitrile solution is introduced from the inlet for rinsing.

[0247] The above second to sixth steps are repeated until all oligonucleotide sequences are synthesized.

[0248] Finally, the ammonolysis solution is introduced from the inlet to cleave the oligonucleotide from the gold electrode and collect it at the outlet.

[0249] In summary, the microfluidic DNA synthesis chip and its manufacturing method of the present invention include an integrated circuit layer, a microfluidic layer, and a top layer. The upper surface of the integrated circuit layer has an exposed metal electrode array. The synthesis chambers of the upper microfluidic DNA synthesis chip correspond to the metal electrodes one by one, and the metal electrodes are surrounded in the center of the chambers. During the DNA synthesis process, under the control of the peripheral circuit, through the integrated circuit, the addressing and decoding circuit of the chip selects any number of metal electrodes to generate the required stable voltage within a specified time period, causing the components in the solution introduced into the microfluidic layer to undergo an electrolysis reaction to generate hydrogen ions, thereby causing a deprotection reaction and a coupling reaction in the solution. The structure of the microfluidic layer can confine the hydrogen ions generated at each site, avoiding mutual interference between sites caused by hydrogen ion diffusion, eliminating the need for an additional cathodic protection circuit to reduce hydrogen ions to prevent diffusion, or adding alkaline components to the synthesis raw materials to neutralize hydrogen ions to prevent diffusion, greatly reducing the complexity and manufacturing cost of the synthesis chip, and further improving the synthesis density and throughput. The manufacturing method of the microfluidic DNA synthesis chip of the present invention can further reduce the device size, greatly improve the synthesis density, improve the utilization efficiency of the solution, reduce the DNA synthesis cost, achieve high-throughput DNA synthesis, and has simple manufacturing process steps and can be mass-produced. Therefore, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0250] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A microfluidic DNA synthesis chip, characterized in that, Comprising: A microfluidic layer, including a liquid inlet, a main liquid inlet channel, a capillary valve channel, a main liquid outlet channel and a liquid outlet which are connected in sequence. The main liquid inlet channel and the main liquid outlet channel both extend in the Y direction and are spaced apart in the X direction. The capillary valve channel extends in the X direction. The number of the capillary valve channels is multiple, and the multiple capillary valve channels are arranged at intervals in the Y direction. The Y direction is perpendicular to the X direction. The capillary valve channel includes a first capillary valve unit and a second capillary valve unit which are alternately connected in the X direction. Both the first capillary valve unit and the second capillary valve unit include a main path, a microchamber, a capillary valve and a bypass. In each capillary valve unit, the inlet of the microchamber is connected to the outlet of the main path, the outlet of the microchamber is connected to the inlet of the capillary valve, and the inlet of the bypass is connected to the side wall of the main path. The outlet of the bypass of the first capillary valve unit is connected to the inlet of the main path of the second capillary valve unit, and the outlet of the capillary valve of the first capillary valve unit is connected to the side wall of the bypass of the second capillary valve unit. An integrated circuit layer, located below the microfluidic layer. The integrated circuit layer includes a transistor array and an addressing and decoding circuit connected to the transistor array. The transistor array includes a plurality of transistor units arranged in an array. Each transistor unit has a metal electrode, and the metal electrodes correspond to the microchambers one by one. Each metal electrode is exposed in the corresponding microchamber. A top layer, located on the microfluidic layer and covering the main liquid inlet channel, the capillary valve channel and the main liquid outlet channel. The top layer includes a liquid inlet through hole and a liquid outlet through hole. The liquid inlet through hole is communicated with the liquid inlet, and the liquid outlet through hole is communicated with the liquid outlet.

2. The microfluidic DNA synthesis chip according to claim 1, wherein: The bypass includes a horizontal portion extending in the X direction and a vertical portion extending in the Y direction. In each capillary valve unit, the inlet of the vertical portion is connected to the side wall of the main path, and the inlet of the horizontal portion is connected to the outlet of the vertical portion.

3. The microfluidic DNA synthesis chip according to claim 1, wherein: The axis of the main path in the X direction, the geometric center of the microchamber and the axis of the capillary valve in the X direction are located on a straight line.

4. The microfluidic DNA synthesis chip according to claim 1, wherein: The width of the main path is equal to the width of the bypass, and is 0.4 to 0.9 times the distance between the two points farthest apart in the Y direction of the microchamber. The length of the main path is 0.5 to 2 times the distance between the two points farthest apart in the X direction of the microchamber. The width of the capillary valve is less than 0.1 times the width of the main path. The length of the capillary valve is 0.5 to 2 times the distance between the two points farthest apart in the X direction of the microchamber.

5. The microfluidic DNA synthesis chip according to claim 1, wherein: The bottom area of the microchamber is 1 to 10 times the cross-sectional area of the metal electrode.

6. The microfluidic DNA synthesis chip according to claim 1, wherein: The transistor unit includes a substrate, a source electrode, a drain electrode, a gate electrode, an insulating layer and a metal electrode. The source electrode and the drain electrode are located on the upper surface layer of the substrate. The gate electrode is located on the upper surface of the substrate. The insulating layer is located on the upper surface of the substrate and covers the gate electrode. The metal electrode is located on the upper surface of the insulating layer.

7. The microfluidic DNA synthesis chip according to claim 6, wherein: The transistor unit includes a capacitive structure. One of the source and the drain and the gate are electrically connected to the addressing and decoding circuit. The other of the source and the drain is electrically connected to the metal electrode, and the metal electrode serves as one plate of the capacitive structure. The other plate of the capacitive structure includes the substrate or a metal layer parallel to the metal electrode in the insulating layer.

8. The microfluidic DNA synthesis chip according to claim 1, wherein: The addressing and decoding circuit includes at least one of a two-dimensional addressing circuit and a multi-dimensional addressing circuit higher than two dimensions.

9. The microfluidic DNA synthesis chip according to claim 8, wherein: When the addressing and decoding circuit is two-dimensional, the addressing and decoding circuit includes a row addressing circuit and a column addressing circuit. The drains of the transistor units in the same row are connected in series and electrically connected to an output port of the row addressing circuit, and the gates of the transistor units in the same column are connected in series and electrically connected to an output port of the column addressing circuit; or, the sources of the transistor units in the same row are connected in series and electrically connected to an output port of the row addressing circuit, and the gates of the transistor units in the same column are connected in series and electrically connected to an output port of the column addressing circuit; or, the drains of the transistor units in the same column are connected in series and electrically connected to an output port of the column addressing circuit, and the gates of the transistor units in the same row are connected in series and electrically connected to an output port of the row addressing circuit; or, the sources of the transistor units in the same column are connected in series and electrically connected to an output port of the column addressing circuit, and the gates of the transistor units in the same row are connected in series and electrically connected to an output port of the row addressing circuit.

10. The microfluidic DNA synthesis chip according to claim 1, wherein: The material of the top layer includes at least one of polymethyl methacrylate, polydimethylsiloxane, and glass; the material of the microfluidic layer includes at least one of polymethyl methacrylate, polydimethylsiloxane, glass, and silicon; the material of the metal electrode includes at least one of gold and platinum.

11. The microfluidic DNA synthesis chip according to claim 1, characterized in that: The integrated circuit layer includes a dynamic random access memory structure.

12. A method for fabricating a microfluidic DNA synthesis chip, characterized in that, Comprising the following steps: Providing a composite layer structure, the composite layer structure including a microfluidic layer and a top layer located on the microfluidic layer; Providing an integrated circuit layer; Bonding the side of the composite layer structure having the microfluidic layer to the integrated circuit layer; Wherein, the microfluidic layer includes a liquid inlet, a liquid inlet main channel, a capillary valve channel, a liquid outlet main channel and a liquid outlet which are sequentially connected. The liquid inlet main channel and the liquid outlet main channel both extend in the Y direction and are spaced apart in the X direction. The capillary valve channel extends in the X direction. The number of the capillary valve channels is multiple, and the multiple capillary valve channels are arranged at intervals in the Y direction. The Y direction is perpendicular to the X direction. The capillary valve channel includes a first capillary valve unit and a second capillary valve unit which are alternately connected in the X direction. Both the first capillary valve unit and the second capillary valve unit include a main path, a microcavity, a capillary valve and a bypass. In each capillary valve unit, the inlet of the microcavity is connected to the outlet of the main path, the outlet of the microcavity is connected to the inlet of the capillary valve, and the inlet of the bypass is connected to the side wall of the main path. The outlet of the bypass of the first capillary valve unit is connected to the inlet of the main path of the second capillary valve unit, and the outlet of the capillary valve of the first capillary valve unit is connected to the side wall of the bypass of the second capillary valve unit. The integrated circuit layer includes a transistor array and an addressing and decoding circuit connected to the transistor array. The transistor array includes a plurality of transistor units arranged in an array. Each transistor unit has a metal electrode, and the metal electrodes correspond to the microcavities one by one. Each metal electrode is exposed in the corresponding microcavity. The top layer covers the liquid inlet main channel, the capillary valve channel and the liquid outlet main channel and includes a liquid inlet through hole and a liquid outlet through hole. The liquid inlet through hole is communicated with the liquid inlet, and the liquid outlet through hole is communicated with the liquid outlet.

13. The manufacturing method of the microfluidic DNA synthesis chip according to claim 12, characterized in that, The formation of the composite layer structure includes the following steps: Provide a substrate, and the substrate includes an upper surface and a lower surface which are oppositely arranged; Pattern the substrate from the upper surface of the substrate to obtain the liquid inlet, the liquid inlet main channel, the capillary valve channel, the liquid outlet main channel and the liquid outlet; Pattern the substrate from the lower surface of the substrate to obtain the liquid inlet through hole and the liquid outlet through hole; Wherein, the layer of the substrate having the liquid inlet, the liquid inlet main channel, the capillary valve channel, the liquid outlet main channel and the liquid outlet serves as the microfluidic layer, and the layer of the substrate having the liquid inlet through hole and the liquid outlet through hole serves as the top layer.

14. The manufacturing method of the microfluidic DNA synthesis chip according to claim 12, wherein The formation of the composite layer structure includes the following steps: Provide a carrier substrate, form a photoresist layer on the carrier substrate, and pattern the photoresist layer to obtain an opening with a preset shape; Form a molding layer by an inverse molding method. The molding layer covers the photoresist layer and fills into the opening; Planarize the upper surface of the molding layer and heat-cure the molding layer; Peel the molding layer from the surfaces of the carrier substrate and the photoresist layer. Wherein, the side of the molding layer facing the photoresist layer is formed with the liquid inlet, the liquid inlet main channel, the capillary valve channel, the liquid outlet main channel and the liquid outlet; Punch holes in the molding layer to obtain the liquid inlet through hole and the liquid outlet through hole; Among them, the layer of the molding layer having the liquid inlet, the liquid inlet main channel, the capillary valve channel, the liquid outlet main channel and the liquid outlet is used as the microfluidic layer, and the layer of the molding layer having the liquid inlet through hole and the liquid outlet through hole is used as the top layer.

15. The manufacturing method of the microfluidic DNA synthesis chip according to claim 12, characterized in that, The formation of the composite layer structure includes the following steps: Providing a substrate, the substrate includes a stacked first substrate layer and a second substrate layer; Patterning the first substrate layer from the surface of the first substrate layer away from the second substrate layer to obtain the liquid inlet, the liquid inlet main channel, the capillary valve channel, the liquid outlet main channel and the liquid outlet; Patterning the second substrate layer from the surface of the second substrate layer away from the first substrate layer to obtain the liquid inlet through hole and the liquid outlet through hole; Among them, the first substrate layer is used as the microfluidic layer, and the second substrate layer is used as the top layer.

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