Developing method and preparation method for dry film microstructure

Abstract

The invention discloses a developing method and a preparation method for a dry film microstructure, and relates to the technical field of semiconductor integrated circuit manufacturing. The dry film microstructure comprises at least two dry film layers, each dry film layer is provided with a channel penetrating through the dry film layer in the thickness direction of the dry film layer, the channels in every two adjacent dry film layers are communicated, the pore diameters of the channels in the dry film layers are sequentially reduced from bottom to top, and the pore diameter ratio of every two adjacent channels is any value of 0.5-0.8. The developing method comprises the following steps: placing the dry film microstructure in a developing solution for ultrasonic treatment; carrying out cleaning treatment on the developed dry film microstructure; wherein the ultrasonic time of the ultrasonic treatment is any one value from 10 min to 60 min, the ultrasonic temperature is any one value from 23 DEG C to 40 DEG C, and the ultrasonic power is any one value from 40 W to 1500 W. According to the developing method, the developing residues left in the bottom layer dry film cavity and the falling upper layer dry film material can be effectively removed.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor integrated circuit manufacturing, and particularly relates to a developing method and a preparation method for a dry film microstructure. Background Art

[0002] Dry film photoresist is a negative photoresist different from conventional liquid photoresist. As a solid photoresist without solvent, it can be stacked in multiple layers and is gradually used as a material for building microfluidic channel microstructures in microfluidic chips in the manufacture of three-dimensional microstructures.

[0003] In the prior art, when constructing a microchannel by stacking multiple layers of dry film photoresist, a silicon wafer is usually placed on a hot plate to attach the first dry film. The first dry film is lithographically patterned and cured. Then, the silicon wafer with the first dry film is placed on a hot plate to attach the second dry film, and the second dry film is lithographically patterned and cured, and so on, repeating the steps multiple times to form a cavity and a channel structure. However, in the prior art during the development of the second dry film, developing residues and the dropped upper dry film materials will remain in the cavity of the bottom dry film, and the residues cannot be discharged, which will cover the bottom metal, affecting the transmission of electrical signals and resulting in the failure of product functions. Summary of the Invention

[0004] An object of the first aspect of the present invention is to provide a developing method for a dry film microstructure, which solves the technical problem that developing residues and the dropped upper dry film materials remain in the cavity of the bottom dry film and cannot be discharged during the development of multiple layers of dry film in the preparation process of the dry film microstructure in the prior art.

[0005] Another object of the first aspect of the present invention is to further improve the developing quality.

[0006] An object of the second aspect of the present invention is to provide a preparation method for a dry film microstructure including the above-mentioned developing method.

[0007] According to the object of the first aspect of the present invention, the present invention provides a developing method for a dry film microstructure. The dry film microstructure includes at least two dry film layers, and each dry film layer is formed with a channel penetrating along its thickness direction. The channels in adjacent two dry film layers are communicated. The channel pore diameters in each dry film layer are set to gradually decrease from bottom to top, and the ratio of the pore diameters of adjacent two channels is any value in the range of 0.5 - 0.8. The developing method includes:

[0008] Placing the dry film microstructure in a developing solution for ultrasonic treatment;

[0009] Performing a cleaning treatment on the developed dry film microstructure;

[0010] Among them, the ultrasonic time of the ultrasonic treatment is any value from 10 min to 60 min, the ultrasonic temperature is any value from 23 °C to 40 °C, and the ultrasonic power is any value from 40 W to 1500 W. The ultrasonic power is set to increase as the number of dry film layers increases.

[0011] Optionally, the dry film layer is a polyacrylate dry film or an epoxy photosensitive dry film.

[0012] Optionally, the material of the developer is a sodium carbonate solution or a potassium carbonate solution, and the mass fraction of the developer is any value from 1 wt% to 2 wt%.

[0013] Optionally, the thickness of each dry film layer is any value from 29 μm to 31 μm.

[0014] Optionally, after the step of cleaning the developed dry film microstructure, the following is further included:

[0015] Baking the dry film microstructure after the cleaning treatment.

[0016] Optionally, the temperature of the baking treatment is any value from 90 °C to 120 °C, and the time of the baking treatment is any value from 30 min to 60 min.

[0017] Optionally, the solution for the cleaning treatment is an isopropyl alcohol solution or an ethanol solution.

[0018] According to the object of the second aspect of the present invention, the present invention further provides a method for preparing a dry film microstructure, including:

[0019] Pre-treating a silicon wafer including a metal film layer;

[0020] Placing the silicon wafer on a hot plate for preheating treatment, and attaching a first dry film layer on the metal film layer;

[0021] Sequentially performing exposure treatment, development treatment, and baking treatment on the first dry film layer to prepare the first dry film layer including a first channel;

[0022] Repeating the preheating treatment, the attaching, the exposure treatment, the development treatment, and the baking treatment steps to prepare the dry film microstructure including at least two dry film layers;

[0023] Among them, the development treatment of the dry film microstructure with the number of dry film layers greater than or equal to 2 is performed according to the development method described in any one of the above.

[0024] Optionally, the preheating temperature is any value from 55 °C to 65 °C.

[0025] Optionally, the metal film layer is made of any one of aluminum, platinum, titanium, and tungsten.

[0026] The present invention sets the aperture of the channels in the dry film microstructure to decrease layer by layer along the thickness direction, and combines the ultrasonic power with the number of dry film layers to enable the developer to flow smoothly from bottom to top and carry the residue to the upper layer. This effectively solves the problems of the bottom channel being easily blocked by particles falling off the upper layer, incomplete development, and structural collapse in the conventional multi-layer dry film structure. The development method is further combined with adjustable ultrasonic time and temperature settings to ensure the adequacy of the development effect and the integrity of the dry film structure, thereby improving the microstructure pattern transfer accuracy and the device finished product yield.

[0027] Furthermore, the material of the developer of the present invention is a sodium carbonate solution, and the mass fraction of the sodium carbonate solution is any value between 1wt% and 2wt%. By using a sodium carbonate solution with a mass fraction of sodium carbonate between 1wt% and 2wt% as the developer, the development rate and development depth of the uncross-linked area in the dry film layer are effectively regulated, while ensuring the adequacy of development, excessive corrosion and blurred graphics are avoided, and the microchannel structure has clear boundaries and uniform morphology, which helps to improve the development quality and structural yield.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0030] Figure 1 is a schematic flow chart of a developing method according to one embodiment of the present invention;

[0031] Figure 2 is a schematic flow chart of a method for preparing a dry film microstructure according to one embodiment of the present invention;

[0032] Figure 3 is a schematic structural diagram of a dry film microstructure according to one embodiment of the present invention;

[0033] Figure 4 FIG. 4 is a schematic structural diagram of a dry film microstructure according to another embodiment of the present invention.

[0034] Reference numerals:

[0035] 100 - Dry film microstructure, 10 - Metal film layer, 20 - Silicon wafer, 30 - First dry film layer, 31 - First channel, 40 - Second dry film layer, 41 - Second channel, 50 - Third dry film layer, 51 - Third channel. Detailed implementation manners

[0036] The following will further describe in detail the specific implementation manners of the present invention in conjunction with the accompanying drawings and embodiments. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0037] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will describe in detail the specific implementation manners of the present application in conjunction with the accompanying drawings. It can be understood that the specific embodiments described herein are only used to explain the present application, rather than limiting the present application. Additionally, it should be noted that for the sake of description, only parts related to the present application are shown in the accompanying drawings rather than all the structures. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.

[0038] The terms "including" and "having" and any variations thereof in the present application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or devices.

[0039] Referring to "embodiments" herein means that specific features, structures, or characteristics described in conjunction with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various positions in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments. [[ID=??]] [[ID=??]]

[0040] [[ID=??]] Figure 1 It is a schematic flowchart of a developing method according to an embodiment of the present invention, Figure 2 It is a schematic flowchart of a method for preparing a dry film microstructure according to an embodiment of the present invention, Figure 3 It is a schematic structural diagram of a dry film microstructure according to an embodiment of the present invention, Figure 4 It is a schematic structural diagram of a dry film microstructure according to another embodiment of the present invention.

[0041] It seems there are some tags with incorrect or unclear numbering in the original text (like the ones marked with "??" above). Please double-check the original text for accuracy.The dry film microstructure 100 includes at least two dry film layers. Each dry film layer is formed with channels penetrating along its thickness direction. The channels in adjacent two dry film layers are communicated. The pore diameters of the channels in each dry film layer are set to decrease successively from bottom to top, and the ratio of the pore diameters of adjacent two channels is any value in the range of 0.5 - 0.8, that is, the ratio of the pore diameters of adjacent two channels can be 0.5, 0.6, 0.7 or 0.8, or any value in the range of 0.5 - 0.8.

[0042] It should be noted that since the dry film microstructure 100 of the present application includes multiple stepped pore structures and the pore diameters of the multiple stepped pore structures gradually decrease from bottom to top. That is, when the second dry film layer, the third dry film layer, the fourth dry film layer or even more dry film layers are successively prepared on the top of the first dry film layer, the developed residues dissolved during the developing process will remain in the cavity etched at the bottom. And as the number of dry film layers increases, the pore diameter of the dry film layer closer to the top is smaller, and it is more difficult for the developed residues falling at the bottom cavity to be discharged outwards. Even after ultrasonic developing treatment after static developing, the developed residues falling on the bottom wall cannot be discharged in time, that is, the developed residues left in the bottom cavity during the developing process of the upper layer cannot be completely removed by subsequent ultrasonic treatment or cleaning treatment.

[0043] As Figure 1 shown, to solve the above problems, the present invention provides a developing method applicable to the multi-layer microchannel dry film microstructure 100. The developing method includes:

[0044] Step S100: Place the dry film microstructure 100 in a developing solution for ultrasonic treatment;

[0045] Step S200: Perform a cleaning treatment on the developed dry film microstructure 100;

[0046] Wherein, the ultrasonic time of the ultrasonic treatment is any value in the range of 10 min - 60 min, the ultrasonic temperature is any value in the range of 23°C - 40°C, the ultrasonic power is any value in the range of 40 W - 1500 W, and the ultrasonic power is set to increase as the number of dry film layers increases.

[0047] In this embodiment, in the developing method for preparing the dry film microstructure 100, at least two dry film layers in the dry film microstructure 100 are developed under ultrasonic treatment conditions, and after the developing treatment, the dry film microstructure 100 is cleaned to remove the developing solution and the residues of the developing solution. Here, the ultrasonic time for ultrasonic treatment of the dry film microstructure 100 can be 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min, or any value in the range of 10 min - 60 min. The ultrasonic temperature can be 23 °C, 25 °C, 27 °C, 29 °C, 30 °C, 32 °C, 34 °C, 36 °C, 38 °C or 40 °C, or any value in the range of 23 °C - 40 °C. The ultrasonic power can be 40 W, 60 W, 80 W,

[0048] 100 W, 200 W, 400 W, 600 W, 700 W, 900 W, 1000 W, 1100 W, 1200 W,

[0049] 1300 W, 1400 W or 1500 W, or any value in the range of 40 W - 1500 W.

[0050] In this embodiment, by setting the pore diameter of the channels in the dry film microstructure 100 to gradually decrease along the thickness direction and matching the ultrasonic power to increase with the number of dry film layers, the developing solution can flow smoothly from bottom to top and carry the residues upward to the upper layer, effectively solving the problems such as the bottom channels in the conventional multi-layer dry film structure being easily blocked by the particles shed from the upper layer, incomplete development, and structural collapse. Moreover, the developing method is further combined with adjustable ultrasonic time and temperature settings, ensuring the sufficiency of the developing effect and the integrity of the dry film structure, and improving the microstructural pattern transfer accuracy and the device finished product yield.

[0051] In a preferred embodiment, the ultrasonic power is any value in the range of 400 W - 1000 W, that is, the ultrasonic power can be 400 W, 450 W, 500 W, 550 W, 600 W, 650 W, 700 W, 750 W, 800 W, 850 W, 900 W, 950 W or 1000 W, or any value in the range of 400 W - 1000 W. By setting the ultrasonic power to any value in the range of 400 W - 1000 W, it is possible to improve the efficiency of shaking off the residues inside the microchannels by the developing solution while avoiding the problems of dry film structure damage or edge collapse caused by excessive ultrasonic energy, thereby ensuring the thoroughness of development while guaranteeing the integrity of the microstructure, and further improving the process yield and functional stability of the microfluidic device.

[0052] In this embodiment, by setting the ultrasonic time of ultrasonic treatment to any value in the range of 10 min to 60 min, the duration of ultrasonic action can be flexibly adjusted according to the number of layers of the dry film structure, the film thickness and the channel complexity. While ensuring that the developing solution fully removes the uncrosslinked regions and residual impurities in the dry film, problems such as film layer damage and structure collapse caused by too long ultrasonic treatment time can be avoided, and the developing accuracy and structural stability of the multi-layer dry film microstructure 100 can be further improved. That is, when the ultrasonic time is in the range of 10 min to 20 min, it is suitable for the dry film microstructure 100 with 2 or 3 layers of dry film layers and the thickness of each dry film layer in the range of 29 μm to 31 μm, so as to facilitate rapid development, with high efficiency and low heat accumulation; when the ultrasonic time is in the range of 20 min to 60 min, it is suitable for the dry film microstructure 100 with the number of dry film layers greater than or equal to 4, thicker film layers or complex channel structures, which helps to fully remove the uncrosslinked regions and residual developing solution at the bottom layer.

[0053] In this embodiment, by setting the ultrasonic temperature to any value in the range of 23 °C to 40 °C, the diffusion and flow performance of the developing solution in the microstructure can be effectively improved, the removal efficiency of the uncrosslinked regions can be enhanced, and at the same time, problems such as softening, deformation or pattern edge collapse of the dry film structure caused by too high temperature can be avoided, so as to ensure the uniformity of the developing process and the integrity of the microstructure, and significantly improve the preparation yield of the dry film microstructure 100. Here, the temperature of the developing solution is controlled by using the cooling module of the lithography equipment.

[0054] In a further embodiment, the dry film layer is a polyacrylate dry film or an epoxy-based photosensitive dry film. Since the photosensitive dry film made of polyacrylic resin material has excellent photosensitive polymerization responsiveness, mechanical strength and interlayer adhesion performance, using polyacrylate-based photosensitive resin as the main base material of the dry film layer can meet the morphological retention and structural accuracy of the multi-layer dry film stacked microstructure during the processes of exposure, development and heat treatment, and significantly improve the process stability and structural integrity of the microfluidic device. In other embodiments, the material of the dry film layer can also be an epoxy-based photosensitive dry film.

[0055] In a further embodiment, the developing solution is made of a sodium carbonate solution or a potassium carbonate solution, and the mass fraction of the developing solution is any value from 1 wt% to 2 wt%. That is, the mass fraction of the sodium carbonate solution can be 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt% or 2 wt%, or can also be any value from 1 wt% to 2 wt%. By using a sodium carbonate solution with a mass fraction of sodium carbonate being any value from 1 wt% to 2 wt% as the developing solution, the developing rate and developing depth of the uncrosslinked region in the dry film layer are effectively regulated, avoiding over-corrosion and pattern blurring while ensuring sufficient development, achieving clear boundaries and uniform morphology of the microchannel structure, which helps to improve the developing quality and the structural yield. Here, the developing solution can also be a potassium carbonate solution.

[0056] In this embodiment, the developing solution further includes an antifoaming agent, and the mass fraction of the antifoaming agent in the developing solution is any value from 0.05 wt% to 0.1 wt%. That is, the mass fraction of the antifoaming agent can be 0.05 wt%, 0.06 wt%,

[0057] 0.07 wt%, 0.08 wt%, 0.09 wt% or 0.1 wt%, or can also be any value from 0.05 wt% to 0.1 wt%. By adding the antifoaming agent with the above mass fraction to the developing solution, the generation of foam during the ultrasonic process can be avoided, improving the stability of the developing treatment.

[0058] In this embodiment, the cleaning difficulties presented by the stepped pore structure within the dry film microstructure 100 are addressed by creating a multi-layered structure with longitudinally connected channels and pore diameters that decrease from bottom to top. By synergistically optimizing the developer composition, ultrasonic temperature, and power, the developer significantly improves cleaning efficiency and structural integrity. Specifically, a sodium carbonate solution with a mass fraction of 1-2 wt% is selected as the developer, exhibiting excellent alkaline solubility and capable of rapidly dissolving the unexposed dry film. Simultaneously, the ultrasonic temperature is controlled between 23°C and 40°C to ensure the fluidity and stability of the developer in the microchannels, suppressing residual bubbles and deformation of the film structure. More crucially, the ultrasonic power is set between 400W and 1000W and increases with the number of dry film layers, thereby enhancing the vibration-induced stripping of particles within the gradually decreasing pores of the upper layer. The combined action of these three factors creates a dynamic development-precision penetration-step cleaning mechanism: sodium carbonate solution provides the basic chemical solubility for development, temperature regulation maintains the developer's penetration efficiency and the membrane material's flexibility, and the increasing power ensures that the ultrasonic energy can gradually penetrate the multi-layer structure and clean the topmost pores. In particular, in the deeply stepped pore structures formed by multiple layers of attached dry films, traditional development methods often face limitations due to the aperture of the upper channels, resulting in difficulty in effectively flushing the bottom cavity and impurity retention. The present invention significantly improves the efficiency of liquid circulation and particle removal through the synergistic effect of these three factors, effectively avoiding problems such as microchannel blockage and metal layer contamination, significantly improving the yield and reliability of microfluidic chips.

[0059] In a further embodiment, the thickness of each dry film layer is any value between 29 μm and 31 μm, i.e., the thickness of each dry film layer can be 29 μm, 29.2 μm, 29.4 μm, 29.6 μm, 29.8 μm, 30 μm, 30.2 μm, 30.4 μm, 30.6 μm, 30.8 μm, or 31 μm, or any value between 29 μm and 31 μm. By setting the thickness of each dry film layer within the above range, the mechanical strength and graphic accuracy of the dry film microstructure 100 can be simultaneously ensured. The height of a single channel layer can also be flexibly adjusted according to design requirements, enabling the precise construction of multi-scale channel structures. Furthermore, layers of different thicknesses can be stacked to form stepped, tapered, differential pressure controlled, and other microchannel systems, facilitating the construction of complex three-dimensional microstructures.

[0060] In a further embodiment, after step S200, the method further includes:

[0061] The cleaned dry film microstructure 100 is baked.

[0062] In this embodiment, by baking the dry film microstructure 100 after the cleaning process, the moisture and residual developer in the dry film layer during the development process and the cleaning process can be removed by the baking process, promoting further cross-linking of the photosensitive polymer chains, improving the mechanical strength of the dry film microstructure 100, and at the same time promoting the chain segment contraction and rearrangement of dry film materials such as polyacrylate, making the inner wall of the microchannel denser and smoother, which is beneficial to the flow consistency and anti-retention performance of the subsequent fluid in the channel.

[0063] In a further embodiment, the temperature of the baking process is any value between 90°C and 120°C, and the time of the baking process is any value between 30 min and 60 min. That is, the temperature of the baking process can be 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, which can be any value between 90°C and 120°C, and the time of the baking process can be 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min, or can also be any value between 30 min and 60 min. By setting the temperature of the baking process between 90°C and 120°C and the time between 30 min and 60 min, the dry film microstructure 100 can effectively remove the residual moisture, enhance the cross-linking density and mechanical strength after development and cleaning, and at the same time ensure firm adhesion between the dry film structures of each layer, and the microchannel structure is clearly formed, thereby improving the preparation yield and reliability of the microfluidic chip.

[0064] In a further embodiment, the solution for the cleaning process is an isopropyl alcohol solution or an ethanol solution. By using an isopropyl alcohol solution or an ethanol solution during the cleaning process, it is beneficial to quickly remove the residual impurities after development and replace the residual moisture in the channel, improving the drying rate and structural cleanliness, thereby ensuring the stability and reliability of the dry film microstructure 100 in the subsequent heat treatment and functional encapsulation steps.

[0065] As Figure 2 shown, the present invention also provides a preparation method for a dry film microstructure 100, and the preparation method includes:

[0066] Step S500: Pretreat the silicon wafer 20 including the metal film layer 10;

[0067] Step S600: Place the silicon wafer 20 on a hot plate for preheating treatment, and attach a first dry film layer 30 on the metal film layer 10;

[0068] Step S700: Perform exposure treatment, development treatment, and baking treatment on the first dry film layer 30 in sequence to prepare a first dry film layer 30 including a first channel 31 (refer to Figure 3 );

[0069] Step S800: Repeat the steps of preheating treatment, attachment, exposure treatment, development treatment, and baking treatment to obtain a dry film microstructure 100 including at least two dry film layers; wherein, the development treatment is performed according to the development method of any one of the above.

[0070] In this embodiment, when preparing the dry film microstructure 100, first, the silicon wafer 20 including the metal film layer 10 is pretreated, and then the pretreated silicon wafer 20 is placed on a hot plate for preheating treatment, and the first dry film layer 30 is attached to the metal film layer 10. After that, the first dry film layer 30 is sequentially subjected to exposure treatment, development treatment, and baking treatment to prepare the first channel 31 in the first dry film layer 30. Then continue with the steps of preheating treatment, attaching the second film layer, exposure treatment, development treatment, and baking treatment to form the second dry film layer 40 including the second channel 41 (refer to Figure 3 ), repeat the steps of continuing preheating treatment, attaching the third film layer, exposure treatment, development treatment, and baking treatment to form the third dry film layer 50 including the third channel 51 (refer to Figure 4 ), so as to prepare a dry film microstructure 100 including three dry film layers. Among them, the development treatment is performed according to the development method of any one of the above. Regarding the development method, it will not be elaborated here one by one.

[0071] In this embodiment, by combining the layer-by-layer attachment and patterning process to preheat and standardize the silicon wafer 20 of the metal film layer 10, and utilizing the stacking characteristics of the dry film photoresist, a high-fidelity construction of the multi-layer dry film microstructure 100 can be achieved. Moreover, in the development stage, combined with the ultrasonic development process, it effectively solves the problems such as the blockage of the flow channel by development residues, structural delamination, or functional failure in the traditional multi-layer dry film processing, significantly improving the structural accuracy, interface quality, and final yield of the microfluidic chip.

[0072] In this embodiment, the number of dry film layers of the dry film microstructure 100 is any value from 1 to 9 layers, that is, the number of dry film layers of the dry film microstructure 100 can be 1 layer, 2 layers, 3 layers, 4 layers, 5 layers, 6 layers, 7 layers, 8 layers, or 9 layers, or any value from 1 - 9 layers. That is, the number of dry film layers in the dry film microstructure 100 can be selectively prepared according to needs. Here, when preparing the first dry film layer 30, ultrasonic treatment may not be performed during the development treatment.

[0073] In a further embodiment, the preheating temperature is any value within 55°C - 65°C, that is, the preheating temperature can be 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C or 65°C, or any value within 55°C - 65°C. By setting the preheating temperature of the metal film layer 10 within the above range, the adhesion between the dry film layer and the metal surface can be effectively improved, the bubble defects during the pasting process can be reduced, and the pattern clarity and structural integrity in the subsequent exposure and development steps can be improved, thereby significantly increasing the yield and reliability of the dry film microstructure 100.

[0074] In this embodiment, after the first dry film layer 30 is developed and baked, gentle preheating within the range of 55°C - 65°C is performed on its surface, which can effectively eliminate the residual stress and surface unevenness introduced in the previous process, and at the same time improve the conformability and alignment accuracy of the second dry film pasted subsequently in the microstructure area, thereby improving the adhesion strength and overall structural integrity between the multi-layer dry film structures, and avoiding defects such as interlayer warping, edge warping or development residues.

[0075] In a further embodiment, the material of the metal film layer 10 is any one of aluminum, platinum, titanium, and tungsten. That is, aluminum has good electrical conductivity, low cost, and excellent processing performance, and can be used as a wire, electrode, or micro-heater layer. Platinum has strong inertness, high chemical stability, and corrosion resistance, and can be used as an electrochemical electrode or a biosensing interface. Titanium has strong adhesion and corrosion resistance and can be used as an adhesion layer, a protective layer, or a microelectrode material. Tungsten has a high melting point and good thermal stability and can be used as a thermoelectric device or a high-temperature resistant metal layer.

[0076] In this embodiment, by setting the metal film layer 10 as any one of aluminum, titanium, platinum, or tungsten, good electrical conductivity, adhesion, corrosion resistance, and thermal stability can be provided respectively according to the requirements of the electrical, thermal, or chemical properties of the device. Moreover, these metal materials have good adhesion and interfacial stability to polyacrylate-based dry films, can improve the bonding strength between the dry film layer and the substrate, and reduce the possible interfacial delamination and functional failure problems during the subsequent development process, thereby significantly increasing the device yield and reliability.

[0077] The present application will be further described in detail below in conjunction with specific embodiments.

[0078] Example 1

[0079] The number of dry film layers of the dry film microstructure 100 is 2. During the development process of the second dry film layer 40, first place the dry film microstructure 100 in the developer for ultrasonic treatment, and after the ultrasonic treatment, perform cleaning treatment and baking treatment on the dry film microstructure 100. Among them, the material of the dry film layer is polyacrylate, the thickness of the dry film layer is 30μm, the developer is a sodium carbonate solution with a mass fraction of 1.5wt%, the mass fraction of the defoamer in the developer is 0.07wt%, the ultrasonic temperature is 30°C, the ultrasonic time is 30min, and the ultrasonic power is 600W.

[0080] Example 2

[0081] The difference between Example 2 and Example 1 is only that the number of dry film layers of the dry film microstructure 100 is 3, and ultrasonic development treatments are performed on both the second dry film layer 40 and the third dry film layer 50, with an ultrasonic power of 700W.

[0082] Example 3

[0083] The difference between Example 3 and Example 1 is only that the number of dry film layers of the dry film microstructure 100 is 4, and ultrasonic development treatments are performed on the second dry film layer 40, the third dry film layer 50, and the fourth dry film layer. The ultrasonic power for the development treatment of the fourth dry film layer is 750W.

[0084] The difference between Example 4 and Example 1 is only that the number of dry film layers of the dry film microstructure 100 is 7, and the ultrasonic power for the development treatment of the seventh dry film layer is 1200W.

[0085] Comparative Example 1

[0086] The difference between Comparative Example 1 and Example 1 is only that the development process includes static development and ultrasonic development, the static development time is 10min, and the ultrasonic development time is 20min.

[0087] Comparative Example 2

[0088] The difference between Comparative Example 2 and Example 1 is only that the development process includes static development and ultrasonic development, the static development time is 10min, and the ultrasonic development time is 30min.

[0089] Perform corresponding residue tests on the cavities of the dry film microstructure 100 after the development treatment in Examples 1 - 4 and Comparative Examples 1 - 2. It is found that there are no residues in the dry film microstructure 100 in Examples 1 - 4, while there are a small amount of development residues at the corners of the bottom cavity and on the bottom wall of the cavity of the dry film microstructure 100 in Comparative Example 1 and Comparative Example 2, indicating that continuous ultrasonic development treatment for a preset time, at a preset temperature, and with a preset power during the development treatment of the stepped dry film microstructure 100 can effectively remove the development residues at the bottom cavity of the dry film microstructure 100.

[0090] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0091] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A developing method for a dry film microstructure, characterized in that The dry film microstructure includes at least two dry film layers. Each dry film layer is formed with channels penetrating along its thickness direction, and the channels in adjacent two dry film layers are communicated. The pore diameters of the channels in each dry film layer are set to decrease successively from bottom to top, and the pore diameter ratio of adjacent two channels is any value in the range of 0.5 - 0.

8. The developing method includes: Placing the dry film microstructure in a developer solution for ultrasonic treatment; Performing a cleaning treatment on the developed dry film microstructure; Wherein, the ultrasonic time of the ultrasonic treatment is any value in the range of 10 min - 60 min, the ultrasonic temperature is any value in the range of 23 °C - 40 °C, and the ultrasonic power is any value in the range of 40 W - 1500 W. The ultrasonic power is set to increase as the thickness of the dry film microstructure increases.

2. The developing method according to claim 1, wherein The dry film layer is a polyacrylate dry film or an epoxy photosensitive dry film.

3. The developing method according to claim 2, wherein The developer solution is made of a sodium carbonate solution or a potassium carbonate solution, and the mass fraction of the developer solution is any value in the range of 1 wt% - 2 wt%.

4. The developing method according to claim 3, wherein The thickness of each dry film layer is any value in the range of 29 μm - 31 μm.

5. The developing method according to claim 4, characterized in that, After the step of performing a cleaning treatment on the developed dry film microstructure, it further includes: Performing a baking treatment on the dry film microstructure after the cleaning treatment.

6. The developing method according to claim 5, wherein The temperature of the baking treatment is any value in the range of 90 °C - 120 °C, and the time of the baking treatment is any value in the range of 30 min - 60 min.

7. The developing method according to any one of claims 1 - 6, wherein The solution for the cleaning treatment is an isopropyl alcohol solution or an ethanol solution.

8. A method for preparing a dry film microstructure, characterized in that, It includes: Performing a pretreatment on a silicon wafer including a metal film layer; Placing the silicon wafer on a hot plate for preheating treatment, and attaching a first dry film layer on the metal film layer; Successively performing an exposure treatment, a developing treatment, and a baking treatment on the first dry film layer to prepare the first dry film layer including a first channel; Repeating the preheating treatment, the attaching, the exposure treatment, the developing treatment, and the baking treatment steps to prepare the dry film microstructure including at least two dry film layers; Wherein, the developing treatment of the dry film microstructure with the number of dry film layers greater than or equal to 2 is performed according to the developing method according to any one of claims 1 - 7.

9. The method for preparing a dry film microstructure according to claim 8, wherein The preheating temperature is any value in the range of 55 °C - 65 °C.

10. The method for preparing a dry film microstructure according to claim 8, wherein The material of the metal film layer is any one of aluminum, platinum, titanium, and tungsten.

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