A wafer-level pulsed laser deposition method and deposition device based on dynamic optical scanning

Abstract

The application relates to a wafer-level pulsed laser deposition method and a deposition device based on dynamic optical scanning, and belongs to the technical field of pulsed laser deposition. The method comprises the following steps: S1, fixing a target material and a substrate in a reaction cavity, and pumping the reaction cavity to vacuum; S2, heating the substrate to a predetermined temperature, and controlling self-rotation of the target material and the substrate; S3, emitting a laser beam into the reaction cavity by using a laser generating device, controlling the incident angle of the laser beam to the surface of the target material to remain constant, and reciprocating the light spot of the laser beam on the surface of the target material along the radial direction of the target material; and controlling the scanning speed of the laser beam, so that the source material of the target material is sputtered and uniformly deposited on the surface of the substrate. The laser beam adopts a two-section inverse speed dynamic optical scanning method, the scanning speed is independently and smoothly regulated in two sections, the energy density at an arbitrary position of the target surface is constant, and the uniformity of film growth is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of pulsed laser deposition technology, and in particular to a wafer-level pulsed laser deposition method and deposition apparatus based on dynamic optical scanning. Background Technology

[0002] Pulsed laser deposition (PLD) boasts advantages such as high consistency between film composition and target material, high crystallinity, and wide material adaptability, making it a core technology for preparing advanced functional thin films such as oxides, nitrides, high-temperature superconductors, piezoelectrics, and ferroelectrics. However, with the development of semiconductors, optoelectronics, and microwave devices towards wafer-level, large-size, and highly uniform designs, traditional PLD equipment and processes face a series of insurmountable technical bottlenecks. 1. Plasma plumes have natural spatial angular distribution characteristics. The larger the wafer diameter, the more obvious the difference in deposition rate between the center and the edge, and the more difficult it is to control the uniformity of film thickness and composition. 2. Traditional uniform linear scanning or simple reciprocating scanning will result in varying laser energy densities (J / cm²) at different radial positions on the target surface. 2 Inconsistency, resulting in over-etching at the center and insufficient etching at the edges, directly leads to the deterioration of film uniformity; 3. Traditional galvanometer / tilt mirror scanning is prone to causing spot distortion and feather shift; 4. Fixed light spot will cause local deep erosion of the target material, resulting in low effective material utilization and frequent target replacement, which reduces equipment efficiency.

[0003] Therefore, there is an urgent need for a wafer-level pulsed laser deposition method and deposition apparatus based on dynamic optical scanning to solve the above-mentioned technical problems. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide a wafer-level pulsed laser deposition method and deposition apparatus based on dynamic optical scanning, in order to solve one of the problems of poor uniformity, easy distortion of the laser spot, unstable energy density, and unreasonable rotation speed matching in the existing technology for large-size wafer PLD deposition.

[0005] In a first aspect, the present invention provides a wafer-level pulsed laser deposition method based on dynamic optical scanning, comprising the following steps: S1. Fix the target and substrate in the reaction chamber and evacuate the reaction chamber to a vacuum. S2. Heat the substrate to a predetermined temperature and control the rotation of the target and the substrate; S3, using a laser generator to emit a laser beam into the reaction chamber, wherein a light spot of the laser beam on the surface of the target reciprocates along the radial direction of the target; controlling the incident angle of the laser beam incident on the target surface to be constant, and regulating the scanning speed of the laser beam, so that the source material of the target is sputtered and uniformly deposited on the surface of the substrate; wherein the scanning speed of the laser beam satisfies the following formula: ; in the formula, : is the scanning speed of the laser beam at a surface position x of the target, with a unit of mm / s; : is the maximum scanning speed of the laser beam, with a value of 5~20 mm / s; : is the minimum scanning speed of the laser beam, with a value of 0.1~5 mm / s; : is the maximum half-distance of the scanning interval of the laser beam on the target surface; : is a speed coefficient; when x<Origin, take the value of Left Coefficient; when x>Origin, take the value of Right Coefficient; : is a critical radius; Origin is the coordinate of the selected scanning origin on the target, with a value of 0~2R; Right Limit is the right scanning boundary of the target, with a value of 0~2R; Left Limit is the left scanning boundary of the target, with a value of 0~2R; R is the radius of the target; Right Coefficient is a right-section speed coefficient, with a value of 1~60; Left Coefficient is a left-section speed coefficient, with a value of 1~60.

[0006] Further, .

[0007] Further, the diameter of the light spot of the laser beam on the target surface is 0.5~2 mm.

[0008] Further, the incident angle of the laser beam incident on the target surface is 30~60°.

[0009] Further, the rotation speed ratio of the target to the substrate is a non-integer ratio within the range of 1.1~1.8:1.

[0010] Furthermore, the substrate rotates at a speed of 0.5~12 r / min.

[0011] Furthermore, When the substrate size is 2 inches, the rotation speed is 5~12 r / min. When the substrate size is 4 inches, the rotation speed is 4~10 r / min; When the substrate size is 6 inches, the rotation speed is 3~8 r / min; When the substrate size is 8 inches, the rotation speed is 2~6 r / min; When the substrate size is 10 inches, the rotation speed is 1~4 r / min; When the substrate size is ≥12 inches, the rotation speed is 0.5~3 r / min.

[0012] Furthermore, the rotational speed of the target material is 0.6~12 r / min.

[0013] Furthermore, the surface of the target material is parallel to the surface of the substrate. When the target material and the substrate have the same size, they are coaxially arranged. Alternatively, when the diameter of the target material is equal to the radius of the substrate, the center point of the target material and the center point of the radius of the substrate are on the same axis. The vertical distance between the target material and the substrate is 50~150 mm.

[0014] Furthermore, the heating temperature of the substrate is 400~850 ℃.

[0015] Furthermore, the energy density of the laser beam is 1.0~4.0 J / cm². 2 .

[0016] Furthermore, when depositing single-crystal oxide thin films, the energy density of the laser beam is 1.5~2.5 J / cm². 2 ; When depositing polycrystalline or amorphous oxide thin films, the energy density of the laser beam is 1.0~2.0 J / cm². 2 ; When depositing nitride thin films, the energy density of the laser beam is 1.5~4.0 J / cm². 2 More preferably, the energy density is 2.0~3.5 J / cm³. 2 .

[0017] Secondly, the present invention provides a pulsed laser deposition apparatus for implementing the above-mentioned wafer-level pulsed laser deposition method based on dynamic optical scanning, comprising a dynamic optical scanning device for adjusting the scanning speed of the laser beam.

[0018] Furthermore, the pulsed laser deposition apparatus further includes: The reaction chamber has a first window, and the interior of the reaction chamber is provided with a target stage for supporting the target material and a substrate stage for supporting the substrate. A laser generator used to produce a laser beam; The dynamic optical scanning device includes a translation stage and a translation drive device. The translation stage is provided with a first reflecting mirror, a second reflecting mirror, and a focusing lens. The laser beam passes through the first reflecting mirror, the second reflecting mirror, and the focusing lens in sequence, and then enters the target surface inside the reaction cavity through the first window. The translation drive device drives the translation stage to reciprocate along the X direction. The X direction is the optical axis direction of the laser beam incident on the first reflector.

[0019] Furthermore, the dynamic optical scanning device also includes a slide rail, the translation stage is slidably connected to the slide rail, and the driving end of the translation drive device is connected to the translation stage.

[0020] Furthermore, it also includes a first rotary drive device, the drive end of which is connected to the target platform.

[0021] Furthermore, the reaction chamber also includes a second window through which the drive end of the first rotary drive device extends into the interior of the reaction chamber.

[0022] Furthermore, it also includes a second rotary drive device, the drive end of which is connected to the substrate stage.

[0023] Furthermore, the reaction chamber also includes a third window through which the drive end of the second rotary drive device extends into the interior of the reaction chamber.

[0024] Furthermore, the end face of the target stage is parallel to the end face of the substrate stage; the target stage and the substrate stage are coaxially arranged, or the center point of the target stage and the center point of the radius of the substrate stage are on the same axis; the vertical distance between the target stage and the substrate stage is 50~150 mm.

[0025] Furthermore, the substrate stage also includes a heater for heating the substrate.

[0026] Furthermore, it also includes a vacuum device located outside the reaction chamber and connected to the reaction chamber, used to maintain a vacuum environment inside the reaction chamber.

[0027] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: 1. This invention dynamically controls the speed of a laser beam using a two-stage inverse speed dynamic optical scanning method. With the origin as the scanning point, the scanning speed is independently and smoothly controlled in two segments using the Left Coefficient and Right Coefficient respectively. A critical radius R is introduced. cn By avoiding singularities in the origin velocity, the laser beam achieves a smooth, non-abrupt velocity throughout its entire trajectory, free from mechanical impact. Simultaneously, by controlling the laser beam incident angle to maintain a constant energy density at any position on the target surface, the intensity and distribution of the plasma plume are uniform, resulting in a significant improvement in the consistency of the film thickness and performance.

[0028] 2. The rotation speed is matched to different wafer (substrate) diameters, with lower speeds for larger wafers. A staggered rotation mode between the substrate and target is employed to eliminate circumferential periodicity, balancing circumferential uniformity and thin film stress control. It supports thin film growth for standard 2-12 inch semiconductor wafers, offering strong compatibility.

[0029] 3. Identify the optimal energy density range for typical materials such as oxides and nitrides, distinguish between single-crystal, polycrystalline, and amorphous film formation conditions, and improve film formation quality and process repeatability.

[0030] 4. This invention breaks through the bottleneck of uneven film thickness caused by traditional fixed spot irradiation. Under the same crystal quality, the film growth rate is significantly improved compared with the traditional mode. It avoids the problems of temperature field disturbance and stress unevenness caused by high-speed movement of the sample stage. It only uses a single laser optical path, without the need for multiple laser arrays. The optical path structure is simple and the equipment cost is greatly reduced. It can achieve a wafer thickness uniformity of ≤3%, which meets the stringent requirements of semiconductor and optoelectronic devices.

[0031] 5. The scanning parameters, rotation speed, energy density, etc. of the pulsed laser deposition method of the present invention can be programmed and saved, supporting automated control and providing a reliable technical route for large-scale production line use.

[0032] 6. This invention adopts an overall translational scanning scheme of reflector-lens group. The installation angle of the reflector and lens is fixed throughout the process without angular offset. The entire optical assembly moves with the translation stage as a whole, controlling the laser incident angle and focusing focal length to remain constant. The spot shape is constant and without distortion, the feathering is not offset, and the plasma state is highly stable. This avoids the spot distortion and feathering offset caused by relying on lens angle deflection to achieve optical path scanning.

[0033] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained through the details specifically pointed out in the description and drawings. Attached Figure Description

[0034] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0035] Figure 1 This is a schematic diagram of the target scanning path in the pulsed laser deposition method of the present invention; Figure 2 This is a schematic diagram of the pulsed laser deposition apparatus of the present invention; Figure 3 This is a schematic diagram of the pulsed laser deposition apparatus of the present invention from another perspective; Figure 4 for Figure 3 Cross-sectional view at point AA; Figure 5 This is a partial enlarged view at point B of the second embodiment of the pulsed laser deposition apparatus of the present invention; Figure 6 This is a graph showing the scanning speed-position relationship of the laser beam spot on the target surface in Example 1. Figure 7 The target ablation status is shown after scanning in Example 1 and Comparative Example 1; Figure 8 This is a comparison diagram of the thickness uniformity of the films prepared in Example 1 and Comparative Example 1.

[0036] In the attached diagram: 100-reaction chamber, 11-first window, 12-second window, 13-third window, 200-laser generator, 21-laser beam, 300-dynamic optical scanning device, 31-translation stage, 311-first reflector, 312-second reflector, 313-focusing lens, 32-translation drive device, 33-slide rail, 400-target stage, 41-target material, 42-first rotation drive device, 500-substrate stage, 51-substrate, 52-second rotation drive device, 600-vacuum device. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] It should be noted that if the embodiments of the present invention involve directional indicators, such as up, down, left, right, front, back, etc., the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0039] Furthermore, if the embodiments of the present invention involve descriptions such as "first" or "second," such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0040] Furthermore, all raw materials mentioned below, unless otherwise specified, are commercially available products; and all process steps or preparation methods not mentioned in detail are process steps or preparation methods known to those skilled in the art.

[0041] This invention provides a wafer-level pulsed laser deposition method based on dynamic optical scanning, comprising the following steps: S1. Fix the target and substrate in the reaction chamber and evacuate the reaction chamber to a vacuum. S2. Heat the substrate to a predetermined temperature and control the rotation of the target and the substrate; S3. A laser beam is emitted into the reaction cavity using a laser generator. The spot of the laser beam on the target surface moves back and forth along the radial direction of the target. The incident angle of the laser beam on the target surface is controlled to be constant, and the scanning speed of the laser beam is adjusted so that the source material of the target is sputtered and uniformly deposited on the surface of the substrate. The scanning speed of the laser beam satisfies the following formula: ; In the formula, The scanning speed of the laser beam at position x on the surface of the target material is expressed in mm / s. The maximum scanning speed of the laser beam is 5~20 mm / s; The minimum scanning speed of the laser beam is 0.1~5 mm / s; : represents the maximum half-distance of the scanning interval of the laser beam on the surface of the target; : velocity coefficient; when x<Origin, the value of Left Coefficient is taken; when x>Origin, the value of RightCoefficient is taken; : critical radius; Origin is the coordinate of the selected scanning origin on the target, with a value ranging from 0 to 2R; Right Limit is the right scanning boundary of the target, with a value ranging from 0 to 2R; Left Limit is the left scanning boundary of the target, with a value ranging from 0 to 2R; R is the radius of the target; Right Coefficient is the right-section velocity coefficient, with a value ranging from 1 to 60; Left Coefficient is the left-section velocity coefficient, with a value ranging from 1 to 60.

[0042] It should be noted that, different from the conventional fixed constant velocity or single linear variable velocity scanning mode of equipment, the present invention controls the incident angle of the laser beam to be constant, dynamically regulates the velocity of the laser beam, adopts two-section asymmetric inverse velocity scanning with a critical radius, takes Origin as the origin (i.e., the boundary point), smoothly regulates the scanning velocity in left and right two sections, the scanning interval is (Left Limit, Right Limit), constant velocity is maintained within the critical radius, and the velocity changes according to the inverse velocity rule outside the critical radius, so as to keep the energy density of the target surface constant. Wherein, near Origin ( ) within the critical radius scanning interval, the velocity is locked , a flat-top region is formed, there is no mathematical singularity, and velocity divergence at the origin is avoided; in the scanning interval far from Origin and between the critical radius and the maximum half-distance ( ), the velocity decreases smoothly, and the left and right sections are independently regulated by different coefficients, so as to ensure constant energy density at any position on the target surface; the scanning interval beyond the maximum half-distance ( ) is automatically limited to , to control the lower limit of velocity. The scanning velocity smoothly falls back to the preset minimum velocity . During the whole scanning process, the movement of the laser beam in the scanning interval is continuous and smooth throughout the whole process, without impact and jump.

[0043] It should be noted that the maximum scanning velocity and the minimum scanning velocity are both preset velocity parameters. It can be understood that, in a specific embodiment, the maximum scanning velocity and minimum scan speed This is a preset fixed value used to limit the speed range of the reverse velocity scan, avoiding velocity divergence at the target origin and the risk of over-etching at the target boundary. The maximum scan speed is specified below. The target rotation period needs to be matched to ensure circumferential homogenization; optionally, it can be 5~20 mm / s. As an example, the maximum scanning speed... The minimum scan rate can be 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, or 20 mm / s, or a range between any two values. To compensate for the wafer edge film thickness, the plasma plume edge attenuation characteristics are matched, optionally ranging from 0.1 to 5 mm / s. As an example, the minimum scan speed... It can be 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 mm / s, or a range between any two values.

[0044] R u Let be the maximum half-distance of the laser beam scanning range on the target surface. Based on the Left Limit, Origin, and Right Limit of the scanning range, the left segment scanning length can be determined as... The right segment scan length is R u That is and The maximum value in the range is defined as follows: Left Limit is the left boundary of the scan, with a scan range of 0 to 2R; Right Limit is the right boundary of the scan, with a scan range of 0 to 2R; and R is the radius of the target material. For example, as shown... Figure 1 As shown, with the target center as the origin, Left Limit, Origin, and Right Limit are marked. The laser beam scans linearly along the target diameter, forming a uniform etching trajectory over the entire area in conjunction with the target's rotation. It can be understood that Left Limit, Origin, and Right Limit are all preset values, selected along the target diameter, with one end of the target diameter marked as 0 and the other end as 2R. Left Limit, Origin, and Right Limit are values ​​between 0 and 2R. Origin can be the center point of the target or a point off-center.

[0045] C vThe velocity coefficient is divided into a left velocity coefficient and a right velocity coefficient, corresponding to the left and right segments of the scanning interval, respectively. These coefficients are used to control the scanning speed of the laser beam in the left and right segments, resulting in more uniform target ablation and thin film growth. Specifically, C... v The parameters are adjusted according to the needs of film thickness distribution, surface roughness, and film crystallinity during growth, with a selection range of 1 to 60. As an example, the left velocity coefficient can be 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or any range between two values. The right velocity coefficient can also be 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or any range between two values. It is understood that different left and right velocity coefficients need to be selected depending on the size of the wafer substrate and the thickness of the film to be grown. During the growth process on the same wafer substrate, the values ​​of the left and right velocity coefficients can also be different. In a specific embodiment, both the left and right velocity coefficients are preset fixed parameters.

[0046] In some implementations, a simplified method for determining the left and right segment velocity coefficients is provided. Once the value of the left or right segment velocity coefficient is determined, it can be referred to a formula. Calculate the corresponding right-segment velocity coefficient or left-segment velocity coefficient. It should be noted that this formula is only a simplified method for determining segmented velocity coefficients; not all left and right segment velocity coefficients need to be determined using this formula. In the actual thin film growth process, the left and right segment velocity coefficients can be adjusted separately according to the actual situation to achieve the best thin film growth effect.

[0047] Critical radius R cn To prevent the velocity from diverging at the origin, the calculation is performed segment by segment based on the velocity coefficients of the left and right segments. The critical radius of the left segment is as follows: Right segment critical radius It is understandable that when the velocity coefficients of the left and right segments are equal, This forms a symmetrical flat-top region; when the velocity coefficients of the left and right segments are not the same... This creates an asymmetric flat-top region, ensuring a smooth and continuous scanning speed throughout the entire process in both cases.

[0048] Understandably, the parameters mentioned above can be adjusted as needed to achieve uniform deposition across the entire target area. For example, when the film growth center is thicker, the laser beam should remain at the target edge for a longer period, which can be achieved by reducing... Alternatively, the Right Coefficient can be increased for adjustment; when the edge of the thin film is too thick, the dwell time of the laser beam at the edge of the target should be reduced, which can be achieved by increasing the Right Coefficient. Alternatively, adjust by reducing the Right Coefficient.

[0049] It should be noted that the aforementioned dynamic scanning control process can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. This computer-readable storage medium can be a disk, optical disk, read-only memory, or random access memory, etc.

[0050] The present invention employs the above-mentioned dynamic scanning method to adapt to wafer substrates of different sizes. For wafer substrates of different sizes, it is necessary to adjust various parameters such as maximum scanning speed, minimum scanning speed, scanning range, and left and right segment speed coefficients accordingly. The control logic is: as the wafer size increases, the control principle changes from symmetrical to asymmetrical scanning. Specifically, (1) small wafers (2 / 4 / 6 inches): the scanning range and left and right segment speed coefficients can be symmetrically configured, and uniform deposition is achieved by relying on symmetrical inverse speed; (2) medium-sized wafers (8 inches): fine-tuning the boundary point Origin and the left and right segment speed coefficients to compensate for the weak asymmetrical distribution of feathers; (3) large wafers (10 / 12 inches): adopting Origin eccentric setting and differentiated configuration of left and right segment speed coefficients to match the edge attenuation characteristics of large-diameter feathers and improve the uniformity of the whole area.

[0051] Specifically, the diameter of the laser beam spot on the target surface is 0.5~2 mm.

[0052] It should be noted that traditional galvanometer and tilting mirror scanning structures typically have a fixed optical base and rely on lens angle offset to achieve optical path scanning, which can easily cause spot distortion and feather deviation, leading to uncontrolled plasma state. This invention controls the laser beam incident angle to be constant at the target surface, ensuring that the laser incident angle and focusing focal length remain unchanged, resulting in a constant and distortion-free spot shape, significantly improving the long-term stability of the optical path and process repeatability. As an example, the diameter of the laser spot can be 0.5, 0.7, 0.9, 1, 1.2, 1.4, 1.6, 1.8, or 2 mm, or any range between two values. A flat-topped laser spot is preferred.

[0053] Specifically, the incident angle of the laser beam onto the target surface is 30° to 60°. As an example, the incident angle of the laser beam can be 30°, 35°, 40°, 45°, 50°, 55°, 60°, or any range between two values.

[0054] Specifically, the rotational speed ratio of the target to the substrate is a non-integer ratio within the range of 1.1 to 1.8:1. As an example, the rotational speed ratio of the target to the substrate can be 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, or a non-integer ratio within a defined range between any two values.

[0055] It should be noted that the target and substrate are rotated at different frequencies to eliminate circumferential periodicity, thus balancing circumferential uniformity and thin film stress control.

[0056] Specifically, the substrate rotation speed is 0.5~12 r / min.

[0057] It should be noted that this invention adjusts the rotation speed according to the substrate size, with the core principle being that the larger the substrate size, the lower the upper limit of the rotation speed. This balances centrifugal stress control and circumferential deposition uniformity, achieving uniform deposition across the entire substrate area. Specifically, when the substrate size is 2 inches, the rotation speed is 5~12 r / min; as an example, the rotation speed can be 5, 6, 7, 8, 9, 10, 11, 12 r / min, or any range between two values.

[0058] When the substrate size is 4 inches, the rotation speed is 4 to 10 r / min; as an example, the rotation speed can be 4, 5, 6, 7, 8, 9, 10 r / min, or any range between two values.

[0059] When the substrate size is 6 inches, the rotation speed is 3 to 8 r / min; as an example, the rotation speed can be 3, 4, 5, 6, 7, 8 r / min, or any range between two values.

[0060] When the substrate size is 8 inches, the rotation speed is 2 to 6 r / min; as an example, the rotation speed can be 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6 r / min, or any range between two values.

[0061] When the substrate size is 10 inches, the rotation speed is 1 to 4 r / min; as an example, the rotation speed can be 1, 1.5, 2, 2.5, 3, 3.5, 4 r / min, or any range between two values.

[0062] When the substrate size is ≥12 inches, the rotation speed is 0.5~3 r / min; as an example, the rotation speed can be 0.5, 0.8, 1, 1.5, 2, 2.5, 3 r / min, or any range between two values.

[0063] Specifically, the rotational speed of the target material is 0.6 to 12 r / min. As an example, the rotational speed can be 0.6, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 r / min, or any range between two values.

[0064] Specifically, the surface of the target material is parallel to the surface of the substrate. When the target material and the substrate have the same size, they are coaxially arranged. Alternatively, when the diameter of the target material is equal to the radius of the substrate, the center point of the target material and the center point of the radius of the substrate are on the same axis. The vertical distance between the target material and the substrate is 50~150 mm. As an example, the vertical distance between the target material and the substrate can be 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150 mm, or any range between two values.

[0065] It should be noted that when applied to small-sized wafers, the substrate and target are positioned opposite each other and coaxially. When applied to large-sized wafers, since large-sized targets are difficult to obtain, a target with a diameter equal to the substrate radius can be used. The target is placed on one side of the wafer, specifically, the center point of the target is coaxial with the center point of the substrate radius. Using the laser optical path scanning of this invention, thin film growth on large-sized wafers can be achieved with good uniformity. Maintaining a suitable distance between the target and the substrate ensures more uniform energy distribution and reduces target spatter.

[0066] Specifically, the heating temperature of the substrate is 400~850 ℃. As an example, the heating temperature can be 400, 450, 500, 550, 600, 650, 700, 750, 800, 850 ℃, or any range between two values.

[0067] It should be noted that this invention defines the optimal energy density range for typical materials such as oxides and nitrides, and distinguishes between single-crystal, polycrystalline, and amorphous film formation conditions. This differentiated design helps improve film formation quality and process repeatability.

[0068] Specifically, the energy density of the laser beam is 1.0~4.0 J / cm². 2 .

[0069] When depositing single-crystal oxide thin films, the energy density of the laser beam is 1.5~2.5 J / cm². 2 For example, the energy density can be 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, or 2.5 J / cm³. 2 , or a range defined between any two values.

[0070] When depositing polycrystalline or amorphous oxide thin films, the energy density of the laser beam is 1.0~2.0 J / cm².2 For example, the energy density can be 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0 J / cm³. 2 , or a range defined between any two values.

[0071] When depositing nitride films, the energy density of the laser beam is 1.5~4.0 J / cm². 2 For example, the energy density could be 1.5, 1.8, 2.0, 2.5, 2.8, 3.0, 3.2, 3.5, or 4.0 J / cm³. 2 The energy density is either 2.0 to 3.5 J / cm³, or a range defined between any two values. More preferably, the energy density is 2.0 to 3.5 J / cm³. 2 .

[0072] like Figures 2 to 5 As shown, in order to realize the above-mentioned wafer-level pulsed laser deposition method based on dynamic optical scanning, the present invention also provides a pulsed laser deposition apparatus, including a dynamic optical scanning device 300, which is used to adjust the scanning speed of the laser beam 21.

[0073] Specifically, the pulsed laser deposition apparatus includes a reaction chamber 100, a laser generator 200, and a dynamic optical scanning device 300. The laser generator 200 is used to generate a laser beam 21. The wavelength, pulse width, repetition frequency, and single pulse energy of the laser generator 200 are continuously adjustable to adapt to the film deposition requirements of different materials such as oxides and nitrides.

[0074] The reaction chamber 100 has a first window 11. Inside the reaction chamber 100, there is a target stage 400 for supporting the target material 41 and a substrate stage 500 for supporting the substrate 51. In some specific embodiments, the reaction chamber 100 also includes a vacuum device 600, located outside the reaction chamber 100 and connected to the reaction chamber 100, for maintaining a vacuum environment inside the reaction chamber 100.

[0075] The dynamic optical scanning device 300 includes a translation stage 31 and a translation drive device 32. The translation stage 31 is equipped with a first reflecting mirror 311, a second reflecting mirror 312, and a focusing lens 313. The laser beam 21 passes sequentially through the first reflecting mirror 311, the second reflecting mirror 312, and the focusing lens 313 before entering the surface of the target material 41 inside the reaction cavity 100 through the first window 11. The translation drive device 32 drives the translation stage 31 to reciprocate along the X direction; the X direction is the optical axis direction of the laser beam 21 incident on the first reflecting mirror 311.

[0076] It should be noted that in existing technologies, scanning is typically performed by adjusting the movement trajectory of the laser beam by changing the angle of the reflector. However, due to the varying lengths of the laser beam 21 path, beam distortion occurs, along with uneven energy density and feather shift, resulting in poor ablation uniformity of the target material 41 and low target utilization. This invention integrates two reflectors and a focusing lens onto a linearly movable translation stage 31, completely abandoning the traditional methods of adjusting the reflector angle or moving the sample stage. The translation drive device 32 drives the translation stage 31 to reciprocate in the X direction, thereby translating the laser beam 21 and enabling the laser beam 21 to actively and linearly scan along the target diameter. Simultaneously, because the angles of the two reflectors are fixed, the incident angle and focal length of the laser beam 21 remain constant throughout the process, resulting in no beam distortion and no feather shift.

[0077] Specifically, the first reflecting mirror 311, the second reflecting mirror 312, and the focusing lens 313 can be fixedly connected to the translation stage 31 using screws and nuts for easy disassembly and relocation. The laser beam 21 generated by the laser generator 200 first reaches the first reflecting mirror 311, is reflected by the first reflecting mirror 311, reaches the second reflecting mirror 312, is reflected by the second reflecting mirror 312, and is focused by the focusing lens 313 before entering the surface of the target material 41 inside the reaction cavity 100 through the first window 11. Since the translation stage 31 can be translated as a whole under the drive of the translation drive device 32, that is, it can make horizontal displacement movement along the X direction, so that the laser beam 21 can move horizontally along the X direction on the surface of the target material 41. Since the double reflecting mirrors and focusing lens are fixed, and the translation stage 31 moves as a whole, the incident angle of the laser beam 21 remains constant. Therefore, the energy density of the laser beam 21 on the surface of the target material 41 is kept constant, which makes the ablation degree of the laser beam 21 on the surface of the target material 41 the same, significantly improving the ablation uniformity of the target material 41 and thus improving the utilization rate of the target material.

[0078] In some specific embodiments, the dynamic optical scanning device 300 further includes a slide rail 33, with the translation stage 31 slidably connected to the slide rail 33, and the driving end of the translation drive device 32 connected to the translation stage 31. The translation drive device 32 can be a known drive motor, such as a pneumatic drive motor or an electric push rod. Optionally, the translation drive device 32 can be connected to an encoder to adjust the stroke and movement speed of the translation stage 31, thereby adjusting the stroke and scanning speed of the laser beam 21 spot to achieve the above-mentioned two-stage reverse speed scanning control method and improve the uniformity and consistency of thin film growth.

[0079] In some specific embodiments, a first rotary drive device 42 is also included, the drive end of which is connected to the target stage 400. The reaction chamber 100 also includes a second window 12, through which the drive end of the first rotary drive device 42 extends into the interior of the reaction chamber 100. The first rotary drive device 42 can be a known rotary motor, used to drive the target stage 400 to rotate clockwise or counterclockwise around the central axis.

[0080] In some specific embodiments, a second rotary drive device 52 is also included, the drive end of which is connected to the substrate stage 500. The reaction chamber 100 also includes a third window 13, through which the drive end of the second rotary drive device 52 extends into the interior of the reaction chamber 100. The second rotary drive device 52 can be a known rotary motor, used to drive the substrate stage 500 to rotate clockwise or counterclockwise along the central axis.

[0081] Inside the reaction chamber 100, the laser beam 21 enters through the first window 11 and irradiates the target material 41. Under sufficiently high energy density and a short pulse time, the target material 41 absorbs the energy of the laser beam 21, causing the temperature at the laser spot to rapidly rise above the evaporation temperature of the target material 41, resulting in high temperature and ablation. The area on the surface of the target material 41 that is hit instantly vaporizes and sputters, ejecting particles such as atoms, ions, electrons, and neutral groups in the form of tiny clusters, micron-sized droplets, and solid particles, forming plasma. The plasma expands along the normal direction of the target material 41 to form a plasma plume. Various particles (atoms, ions, molecular clusters, etc.) in the plume collide with the heated substrate 51 surface at very high speeds. They transfer kinetic energy to the substrate 51, and then physically or chemically adsorb onto the surface of the substrate 51, where they migrate and diffuse, forming small stable atomic clusters (nuclei). As more particles arrive, these nuclei continuously grow, connect with each other, and eventually merge to form a continuous and dense thin film. In some specific embodiments, the substrate stage 500 also includes a heater (not shown) for heating the substrate 51 to the reaction temperature.

[0082] In this embodiment, the laser beam 21 reciprocates radially along the surface of the target 41. It should be noted that the laser beam 21 reciprocates along the diameter of the target 41. For example, the laser beam 21 can start from the center of the target 41, move to the right along the diameter of the target 41, scan to a certain point on the right edge, then return to the left, return to the center of the target 41, continue moving to the left to a certain point on the left edge, then return to the right, return to the center of the target 41, and continue moving to the right, repeating this process. Specifically, in conjunction with the aforementioned pulsed laser deposition method, the laser beam 21 reciprocates radially along the target 41 within the scanning range of (Left Limit, Right Limit). Since the target 41 itself rotates clockwise or counterclockwise along its central axis, the entire surface of the target 41 can be scanned during the movement of the laser beam 21 on the target 41.

[0083] In some specific embodiments, the incident angle of the laser beam 21 onto the surface of the target 41 is 30° to 60°. As an example, the incident angle can be 30°, 35°, 40°, 45°, 50°, 55°, 60°, or any range between two values. More preferably, the sputtering effect of the laser beam 21 on the target 41 is optimal when the incident angle of the laser beam 21 onto the surface of the target 41 is 45°.

[0084] In some specific embodiments, the end face of the target stage 400 is parallel to the end face of the substrate stage 500, and the target stage 400 and the substrate stage 500 are coaxially arranged. To ensure that the laser beam 21 is not blocked by the substrate 51 during scanning, the target-substrate distance between the surface of the target 41 and the surface of the substrate 51 is not less than half the diameter of the substrate 51. Specifically, the vertical distance between the target stage 400 and the substrate stage 500 is 50~150 mm. As an example, the vertical distance can be 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150 mm, or any range between two values. The distance is selected according to the specific size of the substrate 51 to be prepared. By limiting the distance between the target stage 400 and the substrate stage 500, the distance between the target 41 and the substrate 51 is controlled within a suitable range, reducing target 41 spatter. The coaxial arrangement of the target stage 400 and the substrate stage 500 is typically suitable when the size of the substrate 51 is no larger than the size of the target 41. The target 41 and the substrate 51 are placed coaxially.

[0085] Due to the high difficulty in fabricating large-size target materials 41, it is difficult to use target materials 41 of the same size when the substrate 51 is a large-size wafer (e.g., a 12-inch standard wafer). Traditional pulsed laser deposition devices for large-area thin film deposition often use two-dimensional movement or revolution-rotation mode of the sample stage to control the scanning path of the laser beam 21. This method requires limiting the number of laser pulses and growth rate at a single point, which can easily cause temperature field fluctuations and uneven film stress. If a multi-laser array scheme is used, there are problems such as complex optical paths, difficulty in synchronizing multi-beam parameters, and high equipment costs. Therefore, the present invention provides another embodiment suitable for thin film growth on large-size wafers.

[0086] like Figure 5 As shown, in some specific embodiments, the center point of the target stage 400 and the center point of the radius of the substrate stage 500 are on the same axis. It should be noted that when the substrate 51 is a large-size wafer, a small-size target 41 with a diameter equal to the radius of the wafer (substrate 51) is selected. The small-size target 41 is placed on one side of the wafer (substrate 51), so that the center point of the target 41 and the center point of the radius of the wafer (substrate 51) are on the same axis. Since the laser beam 21 reciprocates along the diameter of the target 41, correspondingly, the movement of the laser beam 21 relative to the substrate 51 is reciprocating along the radius of the substrate 51. Because the substrate 51 itself moves clockwise or counterclockwise along its central axis, the plasma plume can perform global deposition on the substrate 51.

[0087] To more clearly describe the present invention, the following embodiments and comparative examples are provided for further illustration.

[0088] Example 1 Adopting such Figure 2 The pulsed laser deposition apparatus shown has the target stage and substrate stage arranged as described above. Figure 5 As shown. Controlling the movement speed of the translation stage in the X direction to control the scanning speed of the laser beam spot for pulsed laser deposition includes the following steps: S1. Fix the target (4-inch Zr) inside the reaction chamber. 0.92 Y 0.08 O 1.96 (YSZ) and a substrate (4-inch wafer), with the distance between the target and the substrate set to 60 mm, and the reaction chamber evacuated to ≤1×10 -6 mbar vacuum; S2. Heat the substrate to 700°C, control the rotation of the target and the substrate, and set the rotation speed of the target to 5 r / min and the rotation speed of the substrate to 7 r / min. S3. A laser beam is emitted into the reaction cavity using a laser generator, with a laser beam energy density of 1.5-2 J / cm². 2The laser beam spot (1.5 mm in diameter) on the target surface reciprocates radially along the target; the laser beam incident angle is 45°. The scanning speed of the laser beam is controlled by setting the following scanning parameters: Right Limit=60, Left Limit=15, Origin=45, Right Coefficient=8, Left Coefficient=22, V... max =10 mm / s, V min =0.5 mm / s. The source material of the target is sputtered and uniformly deposited on the surface of the substrate. The sample is removed after deposition.

[0089] like Figure 6 As shown, the horizontal axis represents the target position x, and the vertical axis represents the scanning speed. According to calculations, the left segment scan length Right segment scan length Therefore, the maximum half-distance R u =30 mm. Left segment critical radius Right segment critical radius Within the critical radius near the origin, the velocity V remains constant. max =10 mm / s, forming a flat-top region; outside the critical radius, the scanning speed changes smoothly in a two-stage inverse speed pattern.

[0090] Example 2 Adopting such Figure 2 The pulsed laser deposition apparatus shown has the target stage and substrate stage arranged as described above. Figure 5 As shown. Controlling the movement speed of the translation stage in the X direction to control the scanning speed of the laser beam spot for pulsed laser deposition includes the following steps: S1. Fix the target (4-inch Zr) inside the reaction chamber. 0.92 Y 0.08 O 1.96 (YSZ) and a substrate (8-inch wafer), with the distance between the target and the substrate set to 60 mm, and the reaction chamber evacuated to ≤1×10 -6 mbar vacuum; S2. Heat the substrate to 700°C, control the rotation of the target and the substrate, and set the rotation speed of the target to 2 r / min and the rotation speed of the substrate to 3 r / min. S3. A laser beam is emitted into the reaction cavity using a laser generator, with a laser beam energy density of 1.5-2 J / cm². 2The laser beam spot (2 mm in diameter) on the target surface reciprocates radially along the target; the laser beam incident angle is 45°. The scanning speed of the laser beam is controlled by setting the following scanning parameters: Right Limit=78, Left Limit=20, Origin=50, Right Coefficient=9, Left Coefficient=20, V... max =12 mm / s, V min =0.6 mm / s. The source material of the target is sputtered and uniformly deposited on the surface of the substrate. The sample is removed after deposition.

[0091] According to calculations, the left segment scan length Right segment scan length Therefore, the maximum half-distance R u =30 mm. Left segment critical radius Right segment critical radius Within the critical radius near the origin, the velocity V remains constant. max =12 mm / s, forming a flat-top region; outside the critical radius, the scanning speed changes smoothly in a two-stage inverse speed pattern.

[0092] Example 3 Adopting such Figure 2 The pulsed laser deposition apparatus shown has the target stage and substrate stage arranged as described above. Figure 4 As shown. Controlling the movement speed of the translation stage in the X direction to control the scanning speed of the laser beam spot for pulsed laser deposition includes the following steps: S1. Fix the target (2-inch Zr) inside the reaction chamber. 0.92 Y 0.08 O 1.96 (YSZ) and a substrate (2-inch wafer), with the distance between the target and the substrate set to 60 mm, and the reaction chamber evacuated to ≤1×10 -6 mbar vacuum; S2. Heat the substrate to 700°C, control the rotation of the target and the substrate, and set the rotation speed of the target to 4 r / min and the rotation speed of the substrate to 6 r / min. S3. A laser beam is emitted into the reaction cavity using a laser generator, with a laser beam energy density of 1.5-2 J / cm². 2The laser beam spot (1.2-1.5 mm in diameter) on the target surface reciprocates radially along the target; the laser beam incident angle is 45°. The scanning speed of the laser beam is controlled by setting the following scanning parameters: Right Limit=45, Left Limit=5, Origin=25, Right Coefficient=14, Left Coefficient=16, V... max =8 mm / s, V min =0.4 mm / s. The source material of the target is sputtered and uniformly deposited on the surface of the substrate. The sample is removed after deposition.

[0093] According to calculations, the left segment scan length Right segment scan length Therefore, the maximum half-distance R u =20 mm. Left segment critical radius. Right segment critical radius Within the critical radius near the origin, the velocity V remains constant. max =8 mm / s, forming a flat-top region; outside the critical radius, the scanning speed changes smoothly in two stages in reverse.

[0094] Comparative Example 1 Comparative Example 1 used the same target and substrate as Example 1. The difference was that the preparation process in Comparative Example 1 employed a conventional pulsed laser deposition apparatus and method. The laser beam position was adjusted by changing the angle of the tilting mirror, and the laser beam spot on the target surface reciprocated along the radial direction of the target at a constant speed of 2 mm / s. The sample was removed after deposition.

[0095] Collect the targets from Example 1 and Comparative Example 1 after deposition. Figure 7 As shown, Figure 7 In the figure, 'a' represents the target material after scanning in Comparative Example 1. The target material has a deep pit in the center and no ablation at the edges. Figure 7 In the diagram, 'b' represents the target material after scanning in Embodiment 1 of this invention, showing uniform ablation across the entire surface. This demonstrates that the pulsed laser deposition apparatus and method of this invention can effectively improve the ablation uniformity of the target material and increase its utilization rate.

[0096] The film thickness of the samples prepared in Example 1 and Comparative Example 1 was measured, and the results are as follows: Figure 8 As shown. The film prepared in Comparative Example 1 has a darker color in the center, poor thickness uniformity, and is thicker in the center and thinner at the edges. The film prepared using the present invention in Example 1 has a uniform thickness distribution, is flat throughout, and has a thickness uniformity of ≤3%.

[0097] In summary, this invention employs a two-segment asymmetric inverse velocity scanning method with a critical radius. Taking the origin as the origin, the scanning speed is smoothly controlled in two segments, left and right, with the scanning range being (Left Limit, Right Limit). Within the critical radius, the speed is constant, while outside the critical radius, it varies according to the inverse velocity law, maintaining a constant energy density on the target surface and ensuring smooth changes in scanning speed. This significantly improves the uniformity of the grown film and is applicable to 2-12 inch wafers, solving the technical bottleneck of high-quality growth of large-size wafers. It also has strong compatibility and a wide range of applications.

[0098] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A wafer-level pulsed laser deposition method based on dynamic optical scanning, characterized in that, Includes the following steps: S1. Fix the target and substrate in the reaction chamber and evacuate the reaction chamber to a vacuum. S2. Heat the substrate to a predetermined temperature and control the rotation of the target and the substrate; S3. A laser beam is emitted into the reaction cavity using a laser generator. The spot of the laser beam on the target surface moves back and forth along the radial direction of the target. The incident angle of the laser beam on the target surface is controlled to be constant, and the scanning speed of the laser beam is adjusted so that the source material of the target is sputtered and uniformly deposited on the surface of the substrate. The scanning speed of the laser beam satisfies the following formula: ； In the formula, The scanning speed of the laser beam at position x on the surface of the target material is expressed in mm / s. The maximum scanning speed of the laser beam is 5~20 mm / s; The minimum scanning speed of the laser beam is 0.1~5 mm / s; The maximum half-distance of the laser beam scanning range on the target surface; : Speed coefficient; when x<Origin, take the value of Left Coefficient; when x>Origin, take the value of RightCoefficient; Critical radius; Origin is the coordinate of the selected scanning origin on the target material, with a value ranging from 0 to 2R; Right Limit is the right boundary of the target material during scanning, with a value ranging from 0 to 2R; Left Limit is the left boundary of the target material during scanning, with a value ranging from 0 to 2R; R is the radius of the target material; The Right Coefficient is the right-side velocity coefficient, with a value ranging from 1 to 60. The Left Coefficient is the velocity coefficient for the left segment, with a value ranging from 1 to 60.

2. The wafer-level pulsed laser deposition method based on dynamic optical scanning according to claim 1, characterized in that, 。 3. The wafer-level pulsed laser deposition method based on dynamic optical scanning according to claim 1, characterized in that, The laser beam has a spot diameter of 0.5~2 mm on the target surface.

4. The wafer-level pulsed laser deposition method based on dynamic optical scanning according to claim 1, characterized in that, The rotational speed ratio between the target and the substrate is a non-integer ratio within the range of 1.1 to 1.8:

1.

5. A wafer-level pulsed laser deposition method based on dynamic optical scanning according to claim 1, characterized in that, The substrate rotates at a speed of 0.5~12 r / min.

6. A wafer-level pulsed laser deposition method based on dynamic optical scanning according to claim 1, characterized in that, The target rotation speed is 0.6~12 r / min.

7. A wafer-level pulsed laser deposition method based on dynamic optical scanning according to claim 1, characterized in that, The surface of the target material is parallel to the surface of the substrate. When the target material and the substrate have the same size, they are coaxially arranged. Alternatively, when the diameter of the target material is equal to the radius of the substrate, the center point of the target material and the center point of the radius of the substrate are on the same axis. The vertical distance between the target material and the substrate is 50~150mm.

8. A wafer-level pulsed laser deposition method based on dynamic optical scanning according to claim 1, characterized in that, The heating temperature of the substrate is 400~850 ℃.

9. A wafer-level pulsed laser deposition method based on dynamic optical scanning according to claim 1, characterized in that, The energy density of the laser beam is 1.0~4.0 J / cm². 2 .

10. A pulsed laser deposition apparatus for implementing the wafer-level pulsed laser deposition method based on dynamic optical scanning according to any one of claims 1 to 9, characterized in that, It includes a dynamic optical scanning device, which is used to adjust the scanning speed of the laser beam.

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