Conformal laser processing method for integrated skeleton coil of quartz flexible accelerometer

Abstract

The present invention discloses a conformal laser processing method for an integrated skeleton coil of a quartz flexible accelerometer, comprising step 1: depositing a composite metal film layer on the coil skeleton; step 2: shaping an ordinary femtosecond Gaussian beam into a double-pulse flat-top beam in the time and space domain; step 3: tightly focusing the femtosecond laser beam; step 4: processing a spiral coil with a sub-micron spacing using a tightly focused femtosecond laser; and step 5: conformally modifying the coated coil. The present invention can realize the integrated processing and forming of the skeleton coil, with small internal stress in the film layer, a more reliable structure of the skeleton coil, stronger impact resistance, smaller thermal gradient, and better chemical stability.

Description

Technical Field

[0001] The invention relates to the technical field of detection instruments, and in particular to a conformal laser processing method for an integrated skeleton coil of a quartz flexible accelerometer. Background Art

[0002] The sensitive element is both the core of the capacitive sensor and a part of the electromagnetic torquer. Its stability and reliability directly determine the performance of the quartz accelerometer and is the core component of the accelerometer. The original structure torquer uses multiple turns of copper wire to wind the metal wire. This method requires coil winding, fixing, bonding and other processes, which is relatively cumbersome.

[0003] The existing acceleration sensitive element film layer generally adopts a binary metal film system structure represented by the Cr+Au double-layer film system. This binary film system has insurmountable principle problems such as large internal stress in the film layer, long-term and slow diffusion of the Cr film and the Au film leading to changes in electrical properties, which affect the stability of the long-term mechanical structure and electrical properties of the film layer, and thus directly affect the long-term stability performance of the accelerometer.

[0004] Therefore, a conformal laser processing method for the integrated skeleton coil of a quartz flexible accelerometer is proposed. Summary of the invention

[0005] The embodiment of the present application provides a conformal laser processing method for an integrated skeleton and coil of a quartz flexible accelerometer. By designing the skeleton and the coil as one, the process flow is reduced, while the structural reliability, impact resistance, and chemical stability are improved and the thermal gradient is reduced.

[0006] The object of the present invention is to provide a conformal laser processing method for an integrated skeleton coil of a quartz flexible accelerometer, aiming to solve or improve at least one of the above-mentioned technical problems.

[0007] To achieve the above object, the present invention provides the following solution: The present invention provides a conformal laser processing method for an integrated skeleton coil of a quartz flexible accelerometer, comprising the following steps:

[0008] Step 1: depositing a composite metal film layer on the coil skeleton 1;

[0009] Step 2: Shape the ordinary femtosecond Gaussian beam into a double-pulse flat-top beam in the time and space domain;

[0010] Step 3: Tightly focus the femtosecond laser beam;

[0011] Step 4: Processing the helical coil 2 with sub-micron spacing using a tightly focused femtosecond laser;

[0012] Step 5: Conformally modify the coated coil.

[0013] According to the conformal laser processing method for the integrated skeleton coil of a quartz flexible accelerometer provided by the present invention, in step 1, the original binary gold / chromium metal film system is changed into a multi-layer metal film system by using the ultra-stable metal composite film system matching technology, and the film layer is plated on the skeleton. Using the principle of strain cancellation between different film layers, one or more layers of different stress characterization film layers are deposited between the Cr film and the Au film, so that the stress inside the film layer cancels each other, and the stress orientation of the entire film system is regulated as a whole according to the demand.

[0014] According to a conformal laser processing method for integrating a skeleton coil of a quartz flexible accelerometer provided by the present invention, in step one, the metal film layer is formed on the outer ring surface of the skeleton 1 by using a magnetron sputtering method.

[0015] According to a conformal laser processing method for integrating a skeleton coil of a quartz flexible accelerometer provided by the present invention, in step 2, an SLM beam shaper and a birefringent crystal are used to shape an ordinary femtosecond Gaussian beam into a double-pulse flat-top beam in the time and space domain.

[0016] According to the conformal laser processing method for skeleton coil integration of a quartz flexible accelerometer provided by the present invention, in step three, based on the principle of femtosecond laser collaborative shaping, the vector beam tight focusing and the coherent superposition super-oscillation principle are used to realize the extremely small space-time convergence light spot beyond the diffraction limit in the far field, and the diameter of the light spot after focusing can reach 1-2 microns.

[0017] According to the conformal laser processing method for the integrated skeleton coil of a quartz flexible accelerometer provided by the present invention, in step 5, a CCD image recognition system is used to determine the position to be modified and the amount to be removed, and iterative modification is performed through in-situ detection, and the coating that is not completely removed is processed again, thereby ensuring that the coating is completely removed and achieving conformal processing of the film layer conductor.

[0018] The present invention discloses the following technical effects:

[0019] The metal composite film matching technology of the quartz pendulum assembly of the present invention deposits one or more layers of different stress characterization films between the Cr film and the Au film, so that the stress inside the film layer cancels each other out. The stress inside the film layer is small, and there will be no change in electrical properties caused by the slow diffusion of the Cr film and the Au film.

[0020] The present invention uses a tightly focused femtosecond laser with time-space shaping to process densely distributed spirally wound metal wires with sub-micron spacing on the surface of a heterogeneous film, and the obtained skeleton coil structure is more reliable, has stronger impact resistance, smaller thermal gradient, and better chemical stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention is further described below in conjunction with the accompanying drawings and embodiments:

[0022] Figure 1 It is a schematic diagram of the structure of the integrated element of the quartz accelerometer skeleton coil provided in the embodiment of the present application;

[0023] Figure 2 It is a schematic diagram of the manufacturing process flow of the quartz accelerometer skeleton coil integrated element provided in the embodiment of the present application;

[0024] The reference numerals are as follows:

[0025] 1-skeleton, 2-helical coil. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Reference Figure 1-2 The present invention provides a conformal laser processing method for an integrated skeleton coil of a quartz flexible accelerometer, comprising the following steps:

[0029] Step 1: depositing a composite metal film layer on the coil skeleton 1;

[0030] Step 2: Shape the ordinary femtosecond Gaussian beam into a double-pulse flat-top beam in the time and space domain;

[0031] Step 3: Tightly focus the femtosecond laser beam;

[0032] Step 4: Processing the helical coil 2 with sub-micron spacing using a tightly focused femtosecond laser;

[0033] Step 5: Conformally modify the coated coil.

[0034] To further optimize the solution, in step 1, the original binary gold / chromium metal film system is changed to a multi-layer metal film system using ultra-stable metal composite film system matching technology, and the film layer is plated on the skeleton. Using the principle of strain cancellation between different film layers, one or more layers of different stress characterization film layers are deposited between the Cr film and the Au film, and the Cu film is generally used as the stress characterization film. The stresses inside the film layers are offset against each other, and the thickness of the Cu film is changed according to demand, thereby regulating the stress orientation of the entire film system.

[0035] According to a further optimization scheme, in step one, the metal film layer is formed on the outer ring surface of the skeleton 1 by using a vacuum sputtering method.

[0036] To further optimize the scheme, in step 2, an SLM beam shaper and a birefringent crystal are used to shape the ordinary femtosecond Gaussian beam into a double-pulse flat-top beam in the spatiotemporal domain.

[0037] Compared with a single-pulse beam, a double-pulse beam can significantly increase the processing depth while improving the processing quality and accuracy. A flat-top beam can significantly reduce the inclination of the spiral microgroove after femtosecond laser processing.

[0038] To further optimize the solution, in step three, based on the principle of collaborative shaping of femtosecond lasers, the vector beam is tightly focused and the coherent superposition super-oscillation principle is used to realize the extremely small spatial and spatial convergence light spot beyond the diffraction limit in the far field. A metal film light-blocking disk is set in the center of the focusing lens to increase the axial polarization component and reduce the radial polarization component in the focused light field, thereby reducing the half-height full width of the focal spot. The diameter of the light spot after focusing reaches 1-2 microns, thereby ensuring that the line spacing of the spiral coil is less than 5 microns.

[0039] To further optimize the solution, in step 4, a rotating shaft and a stepper motor joint control system (not shown in the figure) are used to realize the processing of the ring spiral line. By adjusting the rotation speed of the rotating shaft and the movement speed of the stepper motor, the line width and line spacing of the spiral line can be accurately adjusted.

[0040] To further optimize the solution, in step five, the CCD image recognition system is used to determine the position to be modified and the amount to be removed, and iterative modification is performed through in-situ detection. The coating that has not been completely removed is processed again to ensure that the coating is completely removed.

[0041] The solution is further optimized. In step 2, an infrared femtosecond laser with a wavelength of 1030 nm is used. The 1030 nm infrared femtosecond laser causes less damage to the fused quartz substrate and is suitable for the removal of the composite metal film layer on the surface of the fused quartz substrate.

[0042] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0043] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A conformal laser processing method for the integrated skeleton coil of a quartz flexible accelerometer, characterized in that: The following steps are involved: Step 1: Using ultra-stable metal composite film matching technology, the original binary gold / chromium metal film system is changed into a multi-layer metal film system, and the film layer is plated on the skeleton. Using the principle of strain cancellation between different film layers, one or more layers of different stress characterization film layers are deposited between the Cr film and the Au film, so that the stress inside the film layer cancels each other out, and the stress orientation of the entire film system is regulated as a whole according to the needs; Step 2: Use the SLM beam shaper and birefringent crystal to shape the ordinary femtosecond Gaussian beam into a double-pulse flat-top beam in the time and space domain; Step 3: Based on the principle of collaborative shaping of femtosecond laser, the vector beam is tightly focused and the principle of coherent superposition super-oscillation is used to achieve super-diffraction-limited spot convergence, and the spot diameter after focusing reaches 1-2 microns; Step 4: Processing the helical coil with sub-micron pitch using tightly focused femtosecond laser; Step 5: Use the CCD image recognition system to determine the position to be modified and the amount to be removed, perform iterative modification through in-situ detection, and reprocess the coating that has not been completely removed to ensure that the coating is completely removed.

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