Atomic layer deposition equipment and method based on local direct writing technology

Abstract

The invention discloses atomic layer deposition equipment and method based on a local direct writing technology. The equipment comprises a deposition cavity for limiting a vacuum environment, a temperature-controllable precise displacement platform, a movable local reaction unit integrated with a micro reaction head array and a micro-area sealing structure, a three-dimensional micro-motion mechanism for driving the local reaction unit to do spatial motion, and a multi-source precursor conveying system. According to the method, the local closed or semi-closed reaction micro-area is formed on the surface of the substrate through the micro-area sealing structure, and the atomic-scale high-quality patterned film is directly drawn according to the preset path under the condition that mask and photoetching are not needed in combination with the alternating pulse time sequence of three-dimensional motion control and atomic layer deposition. According to the method, the flexibility of direct writing type printing is combined with the high-quality thin film growth capacity of atomic layer deposition, the problem that high-resolution and complex patterning deposition is difficult to achieve through a traditional ALD technology is effectively solved, and the method is particularly suitable for flexible manufacturing of multi-layer heterostructures and complex micro-nano devices.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing technology and relates to an atomic layer deposition device and method based on local direct writing technology. Specifically, it relates to a device and method that combines direct writing path control with the self-limiting reaction characteristics of atomic layer deposition (ALD) for maskless fabrication of high-resolution patterned thin films. Background Technology

[0002] Atomic layer deposition (ALD) technology has become a core process in the fields of semiconductors, photovoltaics, and nanotechnology due to its superior thickness control (atomic level), excellent uniformity, and conformal properties of high aspect ratio structures. However, traditional ALD processes typically involve full-coverage deposition on the entire substrate surface. To obtain specific thin film patterns, two main approaches are currently used: one is "post-processing," which involves full-film deposition followed by photolithography and etching to remove excess material. This process is lengthy, costly, and the etching solution may damage sensitive materials. The other is "physical masking," which uses a masking plate. However, mask preparation is expensive, alignment is difficult, and frequent mask changes require repeated disruption of the vacuum environment, easily introducing water and oxygen contamination, which severely affects the interface quality of thin films, especially two-dimensional material heterojunctions.

[0003] 3D printing technology, especially direct-write (DIW) printing, can achieve precise local deposition of materials by controlling the movement path of the printhead in three-dimensional space through programming, and has good flexibility in pattern design. However, traditional solution- or slurry-based DIW technology usually deposits films in an amorphous or polycrystalline state, and the crystal quality, density, and thickness uniformity are difficult to reach the level of ALD.

[0004] Therefore, developing a novel device and method that can integrate the high-quality growth characteristics of ALD thin films with the high-flexibility patterning capability of DIW technology, and achieve direct deposition of high-quality patterned thin films without the need for masks and photolithography, is of great significance for promoting innovative development in fields such as flexible electronics, micro-sensors, and integrated optoelectronic devices. Summary of the Invention

[0005] To address the aforementioned issues, this invention discloses an atomic layer deposition apparatus and method based on local direct writing technology. This method combines the high-quality film formation characteristics of ALD with the flexible patterning capabilities of direct writing technology, offering high feasibility. It not only achieves maskless patterning but also effectively prevents lateral diffusion of the precursor through pressure gradients, significantly improving the clarity of the pattern edges.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: An atomic layer deposition apparatus based on local direct-write technology, comprising: A deposition chamber, the interior of which is defined as a vacuum or low-pressure environment; and an internally equipped temperature-controlled precision displacement platform for supporting and heating the substrate; An integrated precursor supply unit is connected to the injection channel of a micro-reactor array via a heated flexible pipeline, and is used for pulsed delivery of two or more gaseous precursors and purge gases. A bypass differential exhaust system is connected to the tail gas suction channels of the deposition chamber and the micro-reaction head array, respectively, to establish the background vacuum of the chamber and directional exhaust of the local reaction zone; A movable local reaction unit, suspended above a temperature-controlled precision displacement platform, includes a micro-reaction head array and a micro-area sealing structure surrounding the array; the micro-reaction head array includes at least one set of independent coaxial precursor injection channels and exhaust gas suction channels. A three-dimensional micro-motion mechanism is connected to the movable local reaction unit and is used to drive it to move in the X, Y, and Z axis directions to adjust the relative position between the micro-reaction head array and the substrate. The control system is used to coordinate the path planning of the three-dimensional micro-motion mechanism, the pulse timing of the integrated precursor supply unit, and the temperature and position of the precision displacement platform.

[0007] Furthermore, the micro-area sealing structure adopts contact sealing or pneumatic non-contact sealing; when contact sealing is adopted, the lower end of the structure is provided with a high-temperature resistant elastic sealing ring, which forms physical isolation by pressing the substrate surface through Z-axis drive in the deposition state; when pneumatic non-contact sealing is adopted, the outer periphery of the structure is provided with an annular inert gas curtain channel, which uses airflow barrier to limit the diffusion of precursor.

[0008] Furthermore, the integrated precursor supply unit includes multiple independent precursor source bottles, a constant temperature heating jacket, a rapid atomic layer deposition valve, and a mass flow controller.

[0009] Furthermore, the micro-reaction head array adopts a modular design with a nozzle orifice diameter of 50-500μm and integrates a microfluidic heater to prevent the precursor from condensing before being ejected.

[0010] Furthermore, the device also includes an in-situ vision alignment system, which includes a high-resolution camera and a coaxial light source disposed outside the deposition chamber, for feedback control of the three-dimensional micro-motion mechanism to perform error compensation.

[0011] Secondly, the present invention also provides a method for preparing patterned thin films based on the above-mentioned atomic layer deposition equipment, comprising the following steps: S1: Install the substrate on a precision displacement platform inside the deposition chamber, evacuate the vacuum and heat the substrate to the preset reaction temperature; S2: The control system drives the movable local reaction unit to move to the first deposition coordinate point according to the preset patterned path data; S3: Drive the movable local reaction unit down along the Z-axis to form a locally closed or semi-closed reaction micro-region between the micro-region sealing structure and the substrate surface; S4: Within the reaction micro-region, the first precursor, purge gas, second precursor, and purge gas are alternately introduced according to the atomic layer deposition process sequence to complete N deposition cycles, where N≥1; S5: Drive the movable local reaction unit to rise along the Z-axis or maintain a micro-suspended state, and move it along a preset path to the next deposition coordinate point; S6: Repeat steps S3 to S5 until all path points are deposited to form a patterned thin film on the substrate; S7: After all patterned thin film layers have been deposited, the deposition chamber is purged and cooled before sampling.

[0012] Furthermore, in step S4, the single pulse time of the atomic layer deposition process sequence is 10ms-2s, the pressure in the local reaction micro-region is maintained at 10-1000Pa, and the background pressure of the deposition chamber is maintained at 1-50Pa, forming a pressure gradient to assist in the exhaust gas discharge.

[0013] Furthermore, the heating temperature of the deposition chamber is 25-800 ℃.

[0014] Furthermore, by changing the number of deposition cycles N at different coordinate points in step S4, three-dimensional relief structure films with thickness gradients are prepared in different regions of the substrate.

[0015] Furthermore, in step S6, the type of precursor in the integrated precursor supply unit is switched online by the control system, and heterogeneous thin film structures of different materials are directly "drawn" in different regions of the same substrate.

[0016] 1. This invention creatively employs a bypass differential exhaust system in conjunction with a micro-area sealing structure to construct a micron-level local reaction environment within a macroscopic vacuum chamber, effectively limiting the lateral diffusion of the precursor. High-resolution patterned deposition can be achieved without any photoresist or physical mask, greatly simplifying the process flow.

[0017] 2. This invention solves the deposition and bonding problem of ALD gaseous precursors during the transportation process by designing a micro-reaction head and its array with a coaxial precursor injection channel and exhaust gas suction channel. At the same time, it ensures the flexibility of the reaction unit movement, making it possible to "draw" patterned complex heterostructures on the same substrate.

[0018] 3. The innovative "step-deposition-movement" working mode of this invention constructs a stable static reaction environment at each coordinate point, effectively avoiding motion interference and ensuring the density and uniformity of the film; at the same time, by independently controlling the number of deposition cycles at each point through the program, a three-dimensional relief structure with a precise thickness gradient can be directly manufactured.

[0019] 4. The entire process is completed continuously in a vacuum environment, which completely avoids the interface contamination caused by repeated vacuum breaking and contact with chemical reagents in the traditional "post-patterning" process, and significantly improves the performance and yield of thin film devices. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the atomic layer deposition apparatus based on local direct writing technology described in this invention.

[0021] Figure 2 This is a bottom view of the movable local reaction unit in this invention.

[0022] Figure 3 This is a schematic diagram of the working state of the movable local reaction unit in this invention: (a) lifting and moving state, (b) pressing and depositing state.

[0023] List of identifiers in attached diagrams: 1-Deposition chamber; 2-Precision displacement platform; 3-Substrate; 4-Movable local reaction unit; 5-Three-dimensional micro-motion mechanism; 6-Micro-area sealing structure (6a-Sealing ring); 7-Micro-reaction head array (7a-Precursor input channel, 7b-Exhaust gas discharge channel); 8-Integrated precursor supply unit (8a, 8b-Precursor source bottle); 9-Vacuum system; 10-Control system; 11-In-situ vision alignment system (11a-CCD camera); 12-Heating device power interface. Detailed Implementation

[0024] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0025] Example 1: like Figure 1 As shown, this specific embodiment 1 provides an atomic layer deposition apparatus based on local direct-write technology, including: The deposition chamber 1 is made of 316L stainless steel and has a temperature-controlled precision displacement platform 2 inside, which is used to support and heat the substrate 3. The temperature control range is from room temperature to 800°C, which limits the vacuum or low-pressure environment for thin film deposition. The integrated precursor supply unit 8 includes four independent precursor source bottles (such as 8a, 8b, etc.) and their external constant temperature heating jacket, rapid atomic layer deposition valve and mass flow controller. It is connected to the injection channel of the local reaction unit 4 in the deposition chamber 1 through a heat-traced flexible pipeline for pulse delivery of two or more gaseous precursors and purge gas. Mobile local reaction unit 4, such as Figure 2 As shown, suspended above the precision displacement platform 2, the structure includes a micro-reaction head array 7 and a micro-area sealing structure 6 surrounding the array. The micro-reaction head array 7 includes at least one set of independent coaxial precursor injection channels 7a and exhaust gas discharge channels 7b, with a nozzle diameter of 100 μm; the micro-area sealing structure 6 adopts a contact sealing design, and a high-temperature resistant perfluoroether rubber (FFKM) elastic sealing ring is provided at the lower end; The three-dimensional micro-motion mechanism 5, which uses a precision electric slide and lead screw module, is connected to the movable local reaction unit 4 and is used to drive it to move with micron-level precision in the X, Y, and Z axis directions.

[0026] The bypass differential exhaust system is connected to the tail gas suction channels of the deposition chamber 1 and the micro-reaction head array, respectively, and is used to establish the background vacuum of the chamber and the directional exhaust of the local reaction zone.

[0027] The control system is electrically connected to the three-dimensional micro-motion mechanism 5, the integrated precursor supply unit 6, and the precision displacement platform 2 for coordinated control.

[0028] The in-situ vision alignment system includes a high-resolution camera (CCD camera) and a coaxial light source located outside the deposition chamber, which are used to provide feedback control for the three-dimensional micro-motion mechanism to perform error compensation.

[0029] In a specific embodiment 1 of the present invention, the bypass differential exhaust system is equipped with a dual-channel vacuum pump. One channel maintains the background pressure of the deposition chamber 1 below 10 Pa, while the other channel is specifically designed to pump air from the micro-region, maintaining the pressure within the micro-region at approximately 200 Pa to create a pressure gradient. The heat-tracing flexible pipeline uses a stainless steel corrugated pipe with an externally wrapped heating tape, and the heating temperature is set to 150°C to prevent precursor condensation.

[0030] However, it should be understood that the specific embodiments of the present invention are not limited thereto. In other specific embodiments, the micro-area sealing structure can be replaced with a pneumatic non-contact seal, utilizing an inert gas curtain to restrict precursor diffusion. The number of precursor source bottles can be expanded to six to accommodate the deposition requirements of complex multi-component compounds. Example

[0031] Specific embodiment 2 of the present invention provides a method for preparing patterned thin films based on the above-mentioned equipment, comprising the following steps: S1: Install a clean substrate 3 (such as a single crystal silicon wafer) on the precision displacement platform 2 inside the deposition chamber 1, start the bypass differential exhaust system to evacuate the vacuum, and heat the substrate to the preset reaction temperature (e.g., 150°C). S2: The control system drives the three-dimensional micro-motion mechanism 5 to move the movable local reaction unit 4 to the first deposition coordinate point according to the preset patterned path data (such as array dot matrix); S3: Drive the movable local reaction unit 4 down along the Z-axis, so that the elastic sealing ring 6a of the micro-area sealing structure contacts the substrate surface and generates a small amount of compression, forming a physically isolated local closed reaction micro-area. S4: Within the reaction micro-region, the first precursor, purge gas, second precursor, and purge gas are alternately introduced through the integrated precursor supply unit 8 according to the ALD process sequence to complete N deposition cycles (e.g., N=50). S5: Drive the movable local reaction unit 4 to rise along the Z-axis (e.g., rise 1 mm) and move along the preset path to the next deposition coordinate point; S6: Repeat steps S3 to S5 until all path points are deposited to form a patterned thin film on the substrate; S7: After all patterned thin film layers have been deposited, the deposition chamber 1 is purged with high-flow-rate nitrogen and cooled down, and then the sample is removed.

[0032] Specifically, this method utilizes a "step-deposition-movement" working mode, coupled with a bypass differential exhaust system, to consistently confine the chemical reaction to a micron-level localized space, while maintaining a high level of cleanliness in the deposition chamber background. This not only achieves maskless patterning but also effectively prevents the lateral diffusion of precursors through pressure gradients, significantly improving the clarity of pattern edges.

[0033] It should be noted that the above content merely illustrates the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, various improvements and modifications can be made without departing from the principle of the present invention, and all such improvements and modifications fall within the scope of protection of the claims of the present invention.

Claims

1. An atomic layer deposition apparatus based on local direct-write technology, characterized in that, include: A deposition chamber, the interior of which is defined as a vacuum or low-pressure environment, and is equipped with a temperature-controlled precision displacement platform for supporting and heating the substrate. An integrated precursor supply unit is connected to the injection channel of a micro-reactor array via a heated flexible pipeline, and is used for pulsed delivery of two or more gaseous precursors and purge gases. A bypass differential exhaust system is connected to the tail gas suction channels of the deposition chamber and the micro-reaction head array, respectively, to establish the background vacuum of the chamber and directional exhaust of the local reaction zone; A movable local reaction unit, suspended above the temperature-controlled precision displacement platform, includes a micro-reaction head array and a micro-area sealing structure surrounding the array; the micro-reaction head array includes at least one set of independent coaxial precursor injection channels and exhaust gas suction channels; A three-dimensional micro-motion mechanism is connected to the movable local reaction unit and is used to drive it to move in the X, Y, and Z axis directions to adjust the relative position between the micro-reaction head array and the substrate. The control system is used to coordinate the path planning of the three-dimensional micro-motion mechanism, the pulse timing of the integrated precursor supply unit, and the temperature and position of the precision displacement platform.

2. The device according to claim 1, characterized in that, The micro-area sealing structure adopts either contact sealing or pneumatic non-contact sealing. When contact sealing is adopted, a high-temperature resistant elastic sealing ring is provided at the lower end of the structure, which forms physical isolation by pressing the substrate surface through Z-axis drive in the deposition state. When pneumatic non-contact sealing is adopted, an annular inert gas curtain channel is provided around the structure to limit the diffusion of precursors by using airflow barriers.

3. The device according to claim 1, characterized in that, The integrated precursor supply unit includes multiple independent precursor source bottles, a constant temperature heating jacket, a rapid atomic layer deposition valve, and a mass flow controller.

4. The device according to claim 1, characterized in that, The micro-reaction head array adopts a modular design with a nozzle orifice diameter of 50-500μm and integrates a microchannel heater to prevent the precursor from condensing before being ejected.

5. The atomic layer deposition apparatus based on local direct-write technology according to claim 1, characterized in that, It also includes an in-situ visual alignment system, which includes a high-resolution camera and a coaxial light source located outside the deposition chamber. The system observes the alignment marks on the substrate surface through the chamber window and uses feedback to control the three-dimensional micro-motion mechanism for error compensation.

6. A method for preparing patterned thin films using the atomic layer deposition apparatus according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Install the substrate on a precision displacement platform inside the deposition chamber, evacuate the vacuum and heat the substrate to the preset reaction temperature; S2: The control system drives the movable local reaction unit to move to the first deposition coordinate point according to the preset patterned path data; S3: Drive the movable local reaction unit down along the Z-axis to form a locally closed or semi-closed reaction micro-region between the micro-region sealing structure and the substrate surface; S4: Within the reaction micro-region, the first precursor, purge gas, second precursor, and purge gas are alternately introduced according to the atomic layer deposition process sequence to complete N deposition cycles, where N≥1; S5: Drive the movable local reaction unit to rise along the Z-axis or maintain a micro-suspended state, and move it along a preset path to the next deposition coordinate point; S6: Repeat steps S3 to S5 until all path points are deposited to form a patterned thin film on the substrate; S7: After all patterned thin film layers have been deposited, the deposition chamber is purged and cooled before sampling.

7. The method for preparing patterned thin films according to claim 6, characterized in that, In step S4, the single pulse time of the atomic layer deposition process sequence is 10ms-2s, the pressure in the local reaction micro-region is maintained at 10-1000Pa, and the background pressure of the deposition chamber is maintained at 1-50Pa, forming a pressure gradient to assist in the exhaust gas discharge; the heating temperature of the deposition chamber is 25-800 ℃.

8. The method for preparing patterned thin films according to claim 6, characterized in that, By changing the number of deposition cycles N at different coordinate points in step S4, three-dimensional relief structures with thickness gradients can be prepared in different regions of the substrate.

9. The method for preparing patterned thin films according to claim 6, characterized in that, In step S6, the type of precursor in the integrated precursor supply unit is switched online by the control system, and heterogeneous thin film structures of different materials are directly "drawn" in different regions of the same substrate.

10. The method for preparing patterned thin films according to claim 6, characterized in that, The substrate includes, but is not limited to, monocrystalline silicon wafers, sapphire, flexible polyimide, glass, or the surface of microelectromechanical system devices with three-dimensional microstructures.

Images