Monolithic resistance-adjustable micro-heating film structure and preparation method thereof

Abstract

The application relates to a monolithic resistance-adjustable micro-heating film structure and a preparation method thereof. The application comprises a substrate, a passivation layer and a heating wire layer arranged in sequence from bottom to top, wherein the heating wire layer forms two independent loops with different lengths to provide different resistance values. In the preparation, the substrate is provided; a passivation photoetching layer is deposited on the surface of the substrate by using a PECVD process; photoresist is uniformly coated on the passivation photoetching layer, and photoetching and developing are carried out to transfer the pattern on a photoetching plate to the passivation photoetching layer; the deposition of metal layers of Ti, Pt and Au or the deposition of metal layers of Ti and Au is sequentially completed by using a magnetron sputtering mode; the metal in the line spacing is stripped by using ultrasonic cleaning to form a single-layer structure of the heating wire layer; and the micro-heating film after stripping is rapidly annealed by using an annealing device. The application can conveniently and quickly adjust the resistance value to adapt to different scenes, reduces the preparation cost and shortens the research and development cycle.

Description

Technical Field

[0001] This invention relates to the field of heating film technology, and in particular to a monolithic micro (micro-nano) heating film structure with adjustable resistance and its preparation method. Background Technology

[0002] Micro-heating films have advantages such as small size, light weight, uniform heating, fast response time, and good electrical insulation, and are widely used in many fields such as national defense, automotive industry, semiconductor laser packaging, environmental science, space science, and information technology.

[0003] Currently used micro-heating films mostly use silicon oxide wafers or ceramic wafers as substrates. The resistance value of the micro-heating film is its core technical indicator. Existing micro-heating film technologies mostly employ high-precision photolithography and nanoscale metal deposition processes to fabricate micro / nano metal wires, achieving precise control over the heating resistance value. However, due to the extremely high requirements for the resistance value and reliability of micro-heating films, the fabrication process requires high precision and is complex, resulting in significant research and development difficulties and long cycles. The required resistance value is difficult to achieve completely in a single process; it requires continuous adjustments to the heating wire layout and metal deposition thickness to change the resistance value. Furthermore, even if the target resistance value can be achieved in a single process, the resistance value of all micro-heating films produced on a single wafer is extremely fixed, making the applicable scenarios very limited, which may affect subsequent experimental progress.

[0004] With the continuous development of science and technology, the pursuit of reducing time and material costs has long been a research hotspot. Due to the highly customized nature of current micro heating films, and the fact that the Ti-Pt-Au used in micro heating films has extremely high purity and the target material is expensive, there is an urgent need to provide a micro heating film that can reduce costs, allows for convenient and rapid resistance adjustment, and is suitable for different scenarios. Summary of the Invention

[0005] Therefore, this invention provides a monolithic micro-heating thin film structure with adjustable resistance and its preparation method, which can conveniently and quickly adjust the resistance value to suit different scenarios, and can reduce the preparation cost and shorten the research and development cycle.

[0006] To address the aforementioned technical problems, this invention provides a monolithic micro-heating thin film structure with adjustable resistance, comprising a substrate, a passivation layer, and a heating wire layer arranged sequentially from bottom to top, wherein the heating wire layer forms two independent loops of different lengths to provide different resistance values.

[0007] In one embodiment of the present invention, the two independent loops of different lengths include a first loop and a second loop. The first loop includes a first transverse segment and a first longitudinal segment extending in the same direction from both ends of the first transverse segment. The first transverse segment and the first longitudinal segment each include two parallel first heating wires, wherein one of the first longitudinal segments includes two first connection ends for connecting pads.

[0008] The second circuit includes a second transverse segment and a second longitudinal segment extending in the same direction from both ends of the second transverse segment. The second transverse segment and the second longitudinal segment are respectively disposed outside the first transverse segment and outside the first longitudinal segment, and their respective lengths are shorter than the first transverse segment and the first longitudinal segment. The second transverse segment and the second longitudinal segment each include two parallel second heating wires, one of which includes two second connection ends for connecting the solder pads.

[0009] In one embodiment of the present invention, the line width of the first heating wire and / or the second heating wire is 80 μm.

[0010] In one embodiment of the present invention, the spacing between the two parallel first heating wires and / or the two parallel second heating wires is 80 μm.

[0011] In one embodiment of the present invention, a 22° rounded corner is provided at the vertical corner of the first circuit and the second circuit.

[0012] In one embodiment of the present invention, the heating wire layer is a single-layer structure, comprising a Ti metal layer, a Pt metal layer and an Au metal layer arranged sequentially from bottom to top; or a Ti metal layer and an Au metal layer arranged sequentially from bottom to top.

[0013] In one embodiment of the present invention, the heating wire layer has a double-layer structure, including a first metal system layer, a silicon dioxide layer and a second metal system layer arranged sequentially from bottom to top; the first metal system layer includes a Ti metal layer and a Pt metal layer arranged sequentially from bottom to top, or a Ti metal layer and an Au metal layer; the second metal system layer includes a Ti metal layer, a Pt metal layer and an Au metal layer arranged sequentially from bottom to top, or a Ti metal layer and an Au metal layer.

[0014] In one embodiment of the present invention, the substrate is a silicon oxide wafer, and an oxide layer is disposed on the back side of the substrate. Both the oxide layer and the passivation layer are made of SiO2.

[0015] This invention also provides a method for preparing a monolithic resistivity adjustable micro-heating thin film structure, comprising:

[0016] Provide substrate;

[0017] A passivation photolithography layer is deposited on the surface of the substrate using a PECVD process;

[0018] Photoresist is uniformly coated on the passivation photolithography layer, and photolithography and development are performed to transfer the pattern on the photomask onto the passivation photolithography layer;

[0019] The deposition of Ti, Pt and Au metal layers, or Ti and Au metal layers, is completed sequentially by magnetron sputtering.

[0020] Ultrasonic cleaning is used to peel off the metal within the wire spacing to form a single-layer heating wire layer.

[0021] The peeled micro-heating film is rapidly annealed using annealing equipment.

[0022] This invention also provides a method for preparing a monolithic resistivity adjustable micro-heating thin film structure, comprising:

[0023] Provide substrate;

[0024] A passivation photolithography layer is deposited on the surface of the substrate using a PECVD process;

[0025] Photoresist is uniformly coated on the passivation photolithography layer, and photolithography and development are performed to transfer the first layer pattern on the photomask to the passivation photolithography layer;

[0026] The deposition of Ti and Pt metal layers, or Ti and Au metal layers, is completed sequentially by magnetron sputtering.

[0027] The metal within the line spacing is stripped using ultrasonic cleaning to form the first metal system layer;

[0028] An insulating photolithography layer was deposited on the first metal system layer using the PECVD process.

[0029] Photoresist is uniformly coated on the insulating photolithography layer, and a window is opened on the insulating photolithography layer to connect it to the first metal system layer. Photolithography and development are performed to transfer the second layer pattern on the photolithography plate to the insulating photolithography layer.

[0030] The deposition of Ti, Pt and Au metal layers, or Ti and Au metal layers, is completed sequentially by magnetron sputtering.

[0031] Ultrasonic cleaning is used to peel off the metal within the line spacing to form a second metal system layer;

[0032] The peeled micro-heating film is rapidly annealed using annealing equipment.

[0033] The technical solution of the present invention has the following advantages compared with the prior art:

[0034] The monolithic adjustable resistance micro heating thin film structure and its preparation method described in this invention can conveniently and quickly adjust the resistance value to suit different scenarios, and can reduce preparation costs and shorten the research and development cycle.

[0035] This invention utilizes two independent heating wire loops of different lengths, allowing for easy adjustment of the resistance value through series or parallel connection, thus providing greater flexibility to adapt to different heating requirements. Because the resistance can be precisely adjusted, the temperature of the heating film can be controlled more precisely, meeting the precise temperature requirements of specific applications. The micro-heating film structure leaves an intermediate area for encapsulating other components, improving device integration and cost-effectiveness. Furthermore, various metal layer material combinations, such as Ti / Pt / Au or Ti / Au, can be selected according to different temperature resistance and resistance requirements, providing greater design flexibility.

[0036] The choice of 80μm linewidth and line spacing in this invention not only facilitates the fabrication process and maintains the integrity of the traces, but also achieves the ideal resistance value with a relatively small metal deposition thickness, thus reducing processing costs.

[0037] The 22° rounded corner treatment at the loop corners of this invention reduces current loss and the risk of trace breakage, enhancing the durability of the micro-heating thin film structure. The double-layer trace structure design effectively counteracts the magnetic field generated by the current, preventing magnetic interference to other sensitive devices. Attached Figure Description

[0038] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0039] Figure 1 This is a schematic diagram of the monolithic adjustable resistance micro heating film structure (single-layer heating line layer) of the present invention.

[0040] Figure 2 This is a schematic diagram of the monolithic adjustable resistance micro heating film structure (double-layer heating line layer) of the present invention.

[0041] Figure 3 This is a schematic diagram of the (first circuit) structure of the heating wire layer of the present invention.

[0042] Figure 4 This is a schematic diagram of the (second circuit) structure of the heating wire layer of the present invention.

[0043] Figure 5 This is a schematic diagram of the first and second circuits connected in series in the heating wire layer of the present invention.

[0044] Figure 6 This is a schematic diagram of the parallel connection of the first and second circuits in the heating wire layer of the present invention.

[0045] Explanation of reference numerals on the accompanying drawings:

[0046] 1. Substrate;

[0047] 2. Passivation layer;

[0048] 3. Heating wire layer; 31. First metal system layer; 32. Silicon dioxide layer; 33. Second metal system layer;

[0049] 4. First circuit; 41. First transverse section; 42. First longitudinal section; 43. First heating wire; 44. First connecting end;

[0050] 5. Second circuit; 51. Second transverse section; 52. Second longitudinal section; 53. Second heating wire; 54. Second connecting end;

[0051] 6. Oxide layer. Detailed Implementation

[0052] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0053] In this invention, when directions (up, down, left, right, front, and back) are described, it is only for the convenience of describing the technical solution of this invention, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0054] In this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number. In the description of this invention, the terms "first" and "second" are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0055] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; a fixed connection, a detachable connection, or an integrally formed connection; a mechanical connection, an electrical connection, or a connection capable of mutual communication; or the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention based on the specific content of the technical solution.

[0056] Example 1

[0057] Reference Figure 1 As shown, a monolithic adjustable resistance micro heating film structure includes a substrate 1, a passivation layer 2, and a heating line layer 3 arranged sequentially from bottom to top. The heating line layer 3 forms two independent loops of different lengths to provide different resistance values.

[0058] Specifically, refer to Figure 2 , Figure 3 As shown, the two independent loops of different lengths include a first loop 4 and a second loop 5. The first loop 4 includes a first transverse segment 41 and a first longitudinal segment 42 extending in the same direction from both ends of the first transverse segment 41. The first transverse segment 41 and the first longitudinal segment 42 each include two parallel first heating wires 43, wherein one of the first longitudinal segments 42 includes two first connection ends 44 for connecting the solder pads.

[0059] The second circuit 5 includes a second transverse segment 51 and a second longitudinal segment 52 extending in the same direction from both ends of the second transverse segment 51. The second transverse segment 51 and the second longitudinal segment 52 are respectively disposed outside the first transverse segment 41 and outside the first longitudinal segment 42, and their respective lengths are shorter than the first transverse segment 41 and the first longitudinal segment 42. The second transverse segment 51 and the second longitudinal segment 52 each include two parallel second heating wires 53, wherein one of the second longitudinal segments 52 includes two second connection ends 54 for connecting the solder pads.

[0060] With the above settings, refer to Figure 5 , Figure 6 As shown, the resistance value can be increased or decreased by connecting the first circuit 4 and the second circuit 5 in series or in parallel.

[0061] Since there are two independent loops, and each loop has a different length, according to the formula:

[0062]

[0063] It can be seen that, given the same resistivity ρ and cross-sectional area S of the grown metal, two different resistance values ​​R can be provided for the heating film due to the different lengths L, namely R_long and R_short.

[0064] Two independent circuits can be connected in series through solder pads. After being connected in series, a heating film structure with a larger resistance can be formed, i.e., Rtotal = Rlength + Rshort.

[0065] Similarly, two independent circuits can be connected in parallel via solder pads. After parallel connection, a heating film structure with lower resistance can be formed, i.e.:

[0066]

[0067] Specifically, in the micro-heating thin film structure of this embodiment, the linewidth of the first heating line 43 and / or the second heating line 53 is 80 μm; the line spacing between the two parallel first heating lines 43 and / or the two parallel second heating lines 53 is 80 μm. This embodiment, through calculation and numerous experiments, demonstrates that an 80 μm linewidth allows the metal deposition thickness to reach a resistance value below 100 Ω within a range not exceeding 1000 nm; while maintaining the same line spacing and linewidth facilitates the fabrication process and ensures the integrity of the wiring.

[0068] Specifically, in this embodiment, the vertical corners of the first circuit 4 and the second circuit 5 are provided with 22° rounded corners. The corners are treated with 22° arc-shaped traces. The 22° arc-shaped traces can reduce current loss at the corners, and compared with the sharpness of right-angle traces and the large arc of 45° traces, the 22° arc-shaped traces are less prone to breakage during the manufacturing process and use.

[0069] The middle area of ​​the micro heating film structure is left blank. Due to the advantage that the micro heating film is easy to integrate with other microelectronic devices, other components can be packaged as needed.

[0070] In this embodiment, refer to Figure 1 As shown, the heating wire layer 3 is a single-layer structure, comprising a Ti metal layer, a Pt metal layer, and an Au metal layer arranged sequentially from bottom to top; or a Ti metal layer and an Au metal layer arranged sequentially from bottom to top. Using a single-layer heating wire to fabricate micro (micro / nano) heating films offers a relatively simple fabrication process and easy adjustment of resistance values.

[0071] In other embodiments, refer to Figure 2As shown, the heating wire layer 3 has a double-layer structure, including a first metal system layer 31, a silicon dioxide layer 32, and a second metal system layer 33 arranged sequentially from bottom to top. The first metal system layer 31 includes a Ti metal layer and a Pt metal layer, or a Ti metal layer and an Au metal layer, arranged sequentially from bottom to top. The second metal system layer 33 includes a Ti metal layer, a Pt metal layer, and an Au metal layer, or a Ti metal layer and an Au metal layer, arranged sequentially from bottom to top. Using a double-layer heating wire structure, the resistance can still be adjusted. Furthermore, because it is a double-layer wiring, the currents can cancel each other out, achieving a non-magnetic effect. The silicon dioxide layer 32 improves the insulation performance of the heating film, ensuring that the circuit still has good electrical performance at high temperatures.

[0072] Specifically, the substrate 1 is a silicon oxide wafer, and an oxide layer 6 is disposed on the back side of the substrate 1. Both the oxide layer 6 and the passivation layer 2 are made of SiO2.

[0073] This monolithic adjustable resistor micro heating film structure changes the single layout of existing micro heating films, and can be used individually, in series or in parallel as needed to achieve a variety of resistance values.

[0074] Example 2

[0075] Reference Figure 1 As shown, this embodiment provides a method for fabricating a monolithic resistive adjustable micro-heating thin film structure, including:

[0076] Step S1: Provide substrate 1; In this embodiment, a 280um silicon oxide wafer is used as substrate 1. Compared with ceramic substrate, silicon oxide substrate is easier to cut to ensure the integrity of the pattern.

[0077] Step S2: A passivation photolithography layer is deposited on the surface of the substrate 1 using a PECVD process; the passivation photolithography layer is a 1000nm thick SiO2 passivation layer; used to improve the insulation performance of the heating film.

[0078] Step S3: Coat the passivation photoresist uniformly on the passivation photolithography layer, and perform photolithography and development to transfer the pattern on the photomask to the passivation photolithography layer;

[0079] Step S4: Deposit Ti, Pt and Au metal layers sequentially using magnetron sputtering (when a high resistance is required), or deposit Ti and Au metal layers sequentially (when a low resistance is required).

[0080] Step S5: Use ultrasonic cleaning to peel off the metal within the wire spacing to form a single-layer heating wire layer 3;

[0081] Step S6: Use an annealing device to perform rapid annealing on the peeled micro heating film to improve its performance.

[0082] Example 3

[0083] Reference Figure 2 As shown, this embodiment provides a method for fabricating a monolithic resistive adjustable micro-heating thin film structure, including:

[0084] Step S1: Provide substrate 1; In this embodiment, a 280um silicon oxide wafer is used as substrate 1;

[0085] Step S2: A passivation photolithography layer is deposited on the surface of the substrate 1 using a PECVD process; the passivation photolithography layer is a 1000nm thick SiO2 passivation layer; used to improve the insulation performance of the heating film;

[0086] Step S3: Uniformly coat photoresist on the passivation photolithography layer, and perform photolithography and development to transfer the first layer pattern on the photomask to the passivation photolithography layer;

[0087] Step S4: Sequentially deposit Ti and Pt metal layers (when high resistance is required) or Ti and Au metal layers (when low resistance is required) using magnetron sputtering.

[0088] Step S5: Use ultrasonic cleaning to peel off the metal within the line spacing to form the first metal system layer 31;

[0089] Step S6: Deposit an insulating photolithography layer on the first metal system layer 31 using PECVD process; the insulating photolithography layer is 500nm thick SiO2, which can prevent short circuits between the upper and lower layers.

[0090] Step S7: Uniformly coat the photoresist on the insulating photolithography layer, and open a window on the insulating photolithography layer to connect it to the first metal system layer 31, perform photolithography and development, and transfer the second layer pattern on the photolithography plate to the insulating photolithography layer.

[0091] Step S8: Deposit Ti, Pt and Au metal layers sequentially using magnetron sputtering, or deposit Ti and Au metal layers.

[0092] Step S9: Use ultrasonic cleaning to peel off the metal within the line spacing to form the second metal system layer 33;

[0093] Step S10: Use an annealing device to perform rapid annealing on the peeled micro heating film to improve its performance.

[0094] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A monolithic, resistance-adjustable micro-heating thin-film structure, characterized in that, It includes a substrate, a passivation layer and a heating wire layer arranged sequentially from bottom to top, wherein the heating wire layer forms two independent loops of different lengths to provide different resistance values; The two independent loops of different lengths include a first loop and a second loop. The first loop includes a first transverse segment and a first longitudinal segment extending in the same direction from both ends of the first transverse segment. The first transverse segment and the first longitudinal segment each include two parallel first heating wires, wherein one of the first longitudinal segments includes two first connection ends for connecting the solder pads. The second circuit includes a second transverse segment and a second longitudinal segment extending in the same direction from both ends of the second transverse segment. The second transverse segment and the second longitudinal segment are respectively disposed outside the first transverse segment and outside the first longitudinal segment, and their respective lengths are longer than the first transverse segment and the first longitudinal segment. The second transverse segment and the second longitudinal segment each include two parallel second heating wires, one of which includes two second connection ends for connecting the solder pads. The first circuit and the second circuit can be connected individually, in series, or in parallel through corresponding connection terminals to form a variety of selectable resistance values ​​on the same monolithic structure; The line width of the first heating wire and / or the second heating wire is 80 μm; The spacing between the two parallel first heating wires and / or the two parallel second heating wires is 80 μm; The vertical corners of the first circuit and the second circuit are provided with 22˚ rounded corners.

2. The monolithic resistance-adjustable micro-heating thin film structure according to claim 1, characterized in that, The heating wire layer is a single-layer structure, comprising a Ti metal layer, a Pt metal layer, and an Au metal layer arranged sequentially from bottom to top; or a Ti metal layer and an Au metal layer arranged sequentially from bottom to top.

3. The monolithic resistance-adjustable micro-heating thin film structure according to claim 1, characterized in that, The heating wire layer has a double-layer structure, including a first metal system layer, a silicon dioxide layer and a second metal system layer arranged sequentially from bottom to top; the first metal system layer includes a Ti metal layer and a Pt metal layer arranged sequentially from bottom to top, or a Ti metal layer and an Au metal layer; the second metal system layer includes a Ti metal layer, a Pt metal layer and an Au metal layer arranged sequentially from bottom to top, or a Ti metal layer and an Au metal layer.

4. The monolithic resistance-adjustable micro-heating thin film structure according to claim 1, characterized in that, The substrate is a silicon oxide wafer, and an oxide layer is disposed on the back side of the substrate. Both the oxide layer and the passivation layer are made of SiO2. 2。 5. A method for preparing a monolithic resistivity adjustable micro-heating thin film structure according to any one of claims 1-4, characterized in that, include: Provide substrate; A passivation photolithography layer is deposited on the surface of the substrate using a PECVD process; Photoresist is uniformly coated on the passivation photolithography layer, and photolithography and development are performed to transfer the pattern on the photomask onto the passivation photolithography layer; The deposition of Ti, Pt and Au metal layers, or Ti and Au metal layers, is completed sequentially by magnetron sputtering. Ultrasonic cleaning is used to peel off the metal within the wire spacing to form a single-layer heating wire layer. The peeled micro-heating film is rapidly annealed using annealing equipment.

6. A method for preparing a monolithic resistivity adjustable micro-heating thin film structure according to any one of claims 1-4, characterized in that, include: Provide substrate; A passivation photolithography layer is deposited on the surface of the substrate using a PECVD process; Photoresist is uniformly coated on the passivation photolithography layer, and photolithography and development are performed to transfer the first layer pattern on the photomask to the passivation photolithography layer; The deposition of Ti and Pt metal layers, or Ti and Au metal layers, is completed sequentially by magnetron sputtering. The metal within the line spacing is stripped using ultrasonic cleaning to form the first metal system layer; An insulating photolithography layer was deposited on the first metal system layer using the PECVD process. Photoresist is uniformly coated on the insulating photolithography layer, and a window is opened on the insulating photolithography layer to connect it to the first metal system layer. Photolithography and development are performed to transfer the second layer pattern on the photolithography plate to the insulating photolithography layer. The deposition of Ti, Pt and Au metal layers, or Ti and Au metal layers, is completed sequentially by magnetron sputtering. Ultrasonic cleaning is used to peel off the metal within the line spacing to form a second metal system layer; The peeled micro-heating film is rapidly annealed using annealing equipment.

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